U.S. patent application number 13/461334 was filed with the patent office on 2012-09-06 for surface treated metal materials, method of treating the surfaces thereof, resin coated metal materials, cans and can lids.
This patent application is currently assigned to TOYO KOHAN CO., LTD.. Invention is credited to Mitsuhide AIHARA, Masatoshi ISHIDA, Wataru KUROKAWA, Norimasa MAIDA, Masanobu MATSUBARA, Hiroshi MATSUBAYASHI, Shigeya TAKAHASHI.
Application Number | 20120222963 13/461334 |
Document ID | / |
Family ID | 35509693 |
Filed Date | 2012-09-06 |
United States Patent
Application |
20120222963 |
Kind Code |
A1 |
ISHIDA; Masatoshi ; et
al. |
September 6, 2012 |
Surface Treated Metal Materials, Method of Treating the Surfaces
Thereof, Resin Coated Metal Materials, Cans and Can Lids
Abstract
A surface-treated metal material having, formed on the surface
of a metal base member, an inorganic surface-treating layer that
contains inorganic components or, further having an organic
surface-treating layer formed on the inorganic surface-treating
layer, the inorganic surface-treating layer containing at least M
(M is at least one of Ti, Zr and Al), O and F. The organic
surface-treating layer contains a silane coupling agent containing
Si in an amount of 0.8 to 30 mg/m.sup.2 or a phenol-type
water-soluble organic compound.
Inventors: |
ISHIDA; Masatoshi;
(Kudomatsu-shi, JP) ; MAIDA; Norimasa;
(Kudomatsu-shi, JP) ; KUROKAWA; Wataru;
(Yokohama-shi, JP) ; MATSUBAYASHI; Hiroshi;
(Yokohama-shi, JP) ; AIHARA; Mitsuhide;
(Yokohama-shi, JP) ; TAKAHASHI; Shigeya;
(Yokohama-shi, JP) ; MATSUBARA; Masanobu;
(Yokohama-shi, JP) |
Assignee: |
TOYO KOHAN CO., LTD.
Tokyo
JP
TOYO SEIKAN KAISHA, LTD.
Tokyo
JP
|
Family ID: |
35509693 |
Appl. No.: |
13/461334 |
Filed: |
May 1, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11571133 |
Dec 21, 2006 |
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PCT/JP2005/011877 |
Jun 22, 2004 |
|
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13461334 |
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Current U.S.
Class: |
205/316 |
Current CPC
Class: |
C25D 11/00 20130101;
Y10T 428/1266 20150115 |
Class at
Publication: |
205/316 |
International
Class: |
C25D 9/08 20060101
C25D009/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 22, 2004 |
JP |
2004-183516 |
Jun 22, 2004 |
JP |
2004-183544 |
Claims
1. A method of treating the surfaces of a metal base member by
forming an inorganic coating on the surfaces of the metal base
member by intermittently conducting a cathodic electrolytic
treatment in an aqueous solution containing Ti and F, and having a
phosphoric acid ion concentration calculated as PO.sub.4 of smaller
than 0.003 mols/liter.
2. The method of treating the surfaces according to claim 1,
wherein said aqueous solution contains Zr.
3. The method of treating the surfaces according to claim 1,
wherein said aqueous solution contains M (M is Ti or Ti and Zr) in
an amount of 0.010 to 0.050 mols/liter and F in an amount of 0.03
to 0.35 mols/liter as bath concentrations.
4. The method of treating the surfaces according to claim 1,
wherein said aqueous solution contains water-dispersing silica.
5. A method of treating the surfaces of a metal base member by
forming an inorganic coating on the surfaces of the metal base
member by intermittently conducting a cathodic electrolytic
treatment in an aqueous solution containing Zr, F and
water-dispersing silica, and having a phosphoric acid ion
concentration calculated as PO.sub.4 of smaller than 0.003
mols/liter.
6. The method of treating the surfaces according to claim 5,
wherein said aqueous solution contains Zr in an amount of 0.010 to
0.050 mols/liter and F in an amount of 0.03 to 0.35 mols/liter as
bath concentrations.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 11/571,133 filed Dec. 21, 2006, which is a 371 of
PCT/JP2005/011877 filed Jun. 22, 2005, which claims priority of
Japanese Application Nos. 2004-183544 filed Jun. 22, 2004 and
2004-183516 filed Jun. 22, 2004; the above noted applications are
incorporated herein by reference in their entirety.
TECHNICAL FIELD
[0002] The present invention relates to surface-treated metal
materials and to a method of treating the surfaces thereof. More
specifically, the invention relates to surface-treated metal
materials which do not use chromium featuring excellent
environmental friendliness and having excellent properties such as
close adhesion to an organic resin coating, adhesive property,
corrosion resistance, dent resistance and wear resistance, to a
method of treating the surfaces of the surface-treated metal
materials, to resin-coated metal materials obtained by coating the
surface-treated metal materials with a resin, to metal cans and can
lids formed by using these resin-coated metal materials.
BACKGROUND ART
[0003] There have heretofore been known a chromate treatment, a
phosphate treatment, a treatment with a silane coupling agent and
an anodic oxidation treatment as treatments for improving close
adhesion of an organic film to metal materials such as steel sheet,
zinc-plated steel sheet, aluminum-plated steel sheet, zinc alloy
sheet, tin-plated steel sheet, aluminum foil, aluminum alloy sheet
and magnesium alloy sheet, and as treatments for joining a metal
material to a metal material of the same kind or of a different
kind by using an adhesive.
[0004] The metal materials utilizing these treatments have been
widely used in such fields as household electric appliances,
building materials, vehicles, aircraft and containers. Among them,
those treated with chromate have been most widely used owing to
their excellent corrosion resistance and close adhesion.
[0005] From the standpoint of treating methods, the chromate
treatments can be roughly divided into those of the formation type
(reaction type, application type) and those of the electrolytic
type. From the standpoint of the formed coatings, on the other
hand, the chromate treatments can be roughly divided into those of
the type which permit trace amounts of hexavalent chromium to
remain in the final products to efficiently utilize the
self-restoring effect and those of the type that do not permit
hexavalent chromium to remain in the final products.
[0006] Concerning the chromate treatments of the type that permit
trace amounts of hexavalent chromium to remain in the final
products, it has been pointed out that hexavalent chromium is
highly probable to elute out into the environment such as the soil
after the disposal. Therefore, it is the trend chiefly in European
countries to ban the chromate treatments. Further, in the chromate
treatments of either type, the treating solution contains
hexavalent chromium which is a toxic substance arousing various
environmental problems. Namely, it becomes necessary to perfectly
treat the drain water of the hexavalent chromium-containing
treating solution and the vented air thereof so will not to be
drained to the exterior. Therefore, a huge sum of cost is necessary
for constructing the facilities for treating the drain water and
the vented air, and for the disposal treatment. Besides, the
regulations have been tightened on transporting the sludge of drain
water and on the vented air. Therefore, it has been urged to
develop a non-chromium surface treatment to substitute for the
traditional chromate treatments.
[0007] A metal sheet for metal containers has, as a matter of
course, been subjected to the chromate treatment of the type that
does not permit hexavalent chromium to remain in the final products
and has, further, been coated with an organic resin or the like.
For example, there have been used a tin-plated steel sheet which is
subjected to the cathodic electrolysis in an aqueous solution of
sodium dichromate, a steel sheet which is subjected to the cathodic
treatment in a fluoride-containing aqueous solution of anhydrous
chromic acid, and an aluminum alloy which is treated with the
chromic phosphate is further coated with an organic resin.
[0008] As a non-chromium surface treatment for a metal sheet of the
type of aluminum alloy, a coating has, in practice, been formed
comprising chiefly an oxide of zirconium and/or titanium on the
surface by using an acidic treating solution containing zirconium,
titanium or a compound thereof as well as phosphate and a fluoride
and having a pH of about 1.0 to 4.0. There has further been placed
in practical use the non-chromium surface treatment without at all
forming the coating depending upon the compatibility with the
organic resin (see JP-A-52-131937).
[0009] In recent years, a precoated material coated with a
polyester resin has been widely used from the standpoint of
sanitation of the metal containers and flavor-retaining property.
When the polyester resin is used, however, water permeates through
as compared with the conventionally used epoxyphenol coating or the
acrylic epoxy coating. Besides, the precoating of the polyester
resin imposes limitation on the content concerning close adhesion
and corrosion resistance unless the chromate treatment is
conducted. Further, when aluminum coated with the polyester resin
is used as an aluminum lid material, there still remains a problem
in that adhesion is not satisfactory despite the chromate treatment
is effected.
[0010] That is, the cans and can lids coated with the polyester
resin, which are examples of the worked products of precoated
materials, offer an advantage of utilizing the precoated metal
sheet as a starting material accompanied, however, by such problems
as a decrease in the close adhesion of the polyester resin at the
highly worked portions such as can wall portions and score portions
of can lids, corrosion starting with the portions where the
polyester resin is cracked due to a shock such as when the can has
fallen, a decrease in the close adhesion during the retort
sterilisation, and inducing corrosion due to permeation of ions
depending upon the components of the content though the polyester
coating itself has no defect, which are different from the problems
of the traditional production method according to which the
surfaces were treated after the can has been formed, and were
post-coated with the coating material.
[0011] On the other hand, metal lids such as can lids are, so far,
using a precoated material obtained by coil-coating the coating
material. From the standpoint of retaining flavor of the content
and sanitation, however, studies have been vigorously conducted in
an attempt to utilize the precoated material which is coated with
the polyester resin. Easy-to-open can lids coated with the
polyester resin permit the occurrence of delamination, i.e.,
exfoliation of the resin from the metal near the score opening due
to a decrease in the adhesion to the polyester resin and drawing of
the resin, i.e., feathering of the resin at the opening being
induced thereby. In particular, the can lid immediately after the
retort sterilization is accompanied by a problem of defective
opening due to a decrease in the adhesion to the resin.
[0012] From the above point of view, there have further been
proposed non-chromium surface treatments of the aluminum alloy-type
metal sheets, such as a method of forming an organic/inorganic
composite coating containing an organic compound using carbon as a
chief component, a phosphorus compound and a zirconium or titanium
compound (JP-A-11-229156), a method of forming a surf ace-treating
layer chiefly comprising an inorganic material on the surface of an
aluminum base member and forming thereon an organic
surface-treating layer comprising chiefly an aqueous phenol resin
(JP-A-2001-121648), and anodic oxidation treatments from the
standpoint of chiefly using as lid members (JP-A-11-91034,
JP-A-2002-266099, JP-A-2005-059471, JP-A-2005-059472. There have
further been proposed treatments by using a polyacrylic acid and a
Zirconium compound (JP-A-06-3225.52 and a journal "Light Metals",
1990, pp. 298-304).
[0013] There has been further proposed a method of forming a
titanium oxide coating by effecting the electrolytic precipitation
on a base sheet in an aqueous solution containing nitric acid ions,
a peroxide and complexing agent and having a pH of larger than 3.0
(JP-A-11-153691).
[0014] On the other hand, many of the non-chromium surface
treatments of the steel sheets have been proposed for the steel
sheets for automobiles and steel sheets for household appliances,
and studies have been conducted concerning vanadate coating,
tungstate Coating, zirconate coating, tannate coating and silicate
coating (journal "Material Stage", 2004, Vol. 4, No. 7, pp. 4-38).
Most of the non-chromium treatments for the steel sheets for
containers are those using the tin-plated steel sheet as an
underlying material. For example, there have been proposed a steel
sheet coated with a layer of a silane coupling agent after the tin
plating and a resin-coated steel sheet (JP-A-2002-11380.9,
JP-A-2002-285354, JP-A-2003-231989, JP-A-2004-345214), a coating
comprising chiefly any one of Ti, Mo or V and a substance stemming
from phosphoric acid and/or a phosphate after having been plated
with tin (JP-A-2001-73185), and a method of forming a composite
oxide film of tungsten and tin by subjecting a base member of tin
to a cathodic periodical electrolysis in a sodium tungstate
solution (journal "Thin Solid Films", 72, 2, 1980, pp. 237-246). As
a non-chromium treatment that can be applied to the aluminum sheet
as well as to the steel sheet and that can be utilized for the
containers, there has been proposed a surface-treated metal
material containing Zr, O and F as chief components but without
containing phosphoric acid ions (JP-A-2005-9771.2).
DISCLOSURE OF THE INVENTION
[0015] According to the method of forming an organic/inorganic
composite coating containing an organic compound having carbon as a
chief component, a phosphorus compound and a zirconium or titanium
compound, the close adhesion improves to some extent but the
corrosion resistance is not sufficient. According to the method of
forming a surface-treating layer comprising chiefly an inorganic
material on the surface of the aluminum base material and forming
an organic surface-treating layer comprising chiefly an aqueous
phenol resin thereon, the close adhesion and corrosion resistance
are both improved to some extent accompanied, however, by such
problems as an increased number of steps and complex treatment of
waste liquor after the chemical solution was used.
[0016] According to the method that utilizes the anodic oxidation
treatment, further, the primary close adhesion is favorable but the
close adhesion drops due to the retort sterilization treatment
after the food or the beverage is packed. Besides, there remain
such problems as an increased cost for the heat-exchanging facility
for cooling the treating solution and for a power source of a large
capacity, and requiring a high running cost consuming large amounts
of electric power for the treatment.
[0017] Further, when the thickness of the base member itself is
small like an aluminum foil, the base member dissolves during the
anodic oxidation treatment or the anodic oxide film which can be
poorly worked occupies an increased proportion causing a decrease
in the flexibility of the foil.
[0018] In treating the aluminum material with a polyacrylic acid
and a zirconium compound, the formed coating is an
organic/inorganic composite coating, and the treating method is
basically the application-type treatment, leaving a problem with
respect to wettability and close adhesion to the metallic base
member during the high-speed treatment.
[0019] Further, many of the prior arts use metal sheets which are
limited to aluminum alloy sheets, and are not capable of solving
the problems of metal materials as a whole.
[0020] When the titanium oxide coating is formed by the cathodic
electrolysis as disclosed in the above JP-A-11-158691, the coating
can be formed at a higher speed than that of the conventional
formation treatment developing, however, the polarization of
concentration near the cathode. As a result, therefore, the
precipitation is impaired making it difficult to efficiently form
the titanium oxide coating.
[0021] A conventional method of forming Al.sub.2O.sub.3 or
ZrO.sub.2 on the surface of the metal material by PVD or CVD can be
employed from the standpoint of treating a variety kinds of
materials. However, the above method must establish a vacuum
condition requiring an increased facility cost and, besides, making
it difficult to conduct the treatment at a high speed resulting in
a further increased cost. It is, further, difficult to maintain the
close adhesion between the metal sheet and the treated film or to
maintain the corrosion resistance after the working. Similarly,
even by using the method, of forming an oxide film by heat-drying
after the organic zirconium compound is applied by the wet method,
it is difficult to maintain the close adhesion between the metal
sheet and the treated film or to maintain the corrosion resistance
after the working.
[0022] The surface treatment comprising Zr, O and F as chief
components but without containing phosphoric acid ions, can be used
for both the aluminum sheet and the steel sheet. When applied to
the tin-plated steel sheet, however, a tin oxide film readily grows
causing discoloration accompanying the passage of time after the
treatment and due to heating.
[0023] It is, therefore, an object of the present invention to
provide a surface-treated metal material which does not use
chromium featuring excellent environmental friendliness, which can
be applied to various materials features excellent discoloration
resistance even when the metal material is a tin-plated steel sheet
and, further, featuring excellent properties such as the close
adhesion to an organic resin coating, adhesive property, corrosion
resistance and dent resistance, and a method of treating the
surfaces of the above surface-treated metal materials.
[0024] Another object of the present invention is to provide a
method of treating the surfaces easily and at a decreased cost
relying upon a high-speed treatment using an aqueous solution.
[0025] A further object of the present invention is to provide
metal cans and can lids featuring excellent close adhesion,
corrosion resistance and dent resistance resulting from the use Of
a resin-coated metal material obtained by coating the above
surface-treated metal material with an organic resin and,
particularly, a polyester resin.
[0026] A still further object of the present invention is to
provide a method of treatment which forms a coating comprising
chiefly Al and O, and can be utilized for iron and aluminum which
are metals much used as structural materials, featuring excellent
environmental friendliness from the standpoint of both quality and
quantity.
[0027] According to the present invention, there is provided a
surface-treated metal material having, formed on the surface of a
metal base member, a surface-treating layer that contains inorganic
components, the inorganic surface-treating layer containing at
least Ti, O and F but without containing phosphoric acid ions.
[0028] In the surface-treated metal material according to a first
aspect of the invention, it is desired that:
1. The surface-treating layer contains Zr; 2. The atomic ratio of P
and M (M is Ti or Ti and Zr) contained in the most surface portion
of the surface-treating layer is 0.ltoreq.P/M<0.6; 3. The atomic
ratio of 0 and M (M is Ti or Ti and Zr) contained in the most
surface portion, of the surface-treating layer is 1<O/M<10;
and 4, The atomic ratio of F and M (M is Ti or Ti and Zr) contained
in the most surface portion of the surface-treating layer is
0.1<F/M<2.5.
[0029] According to the present invention, there is provided a
surface-treated metal material having, formed on the surface of a
metal base member, a surface-treating layer that contains inorganic
components, the Inorganic surface-treating layer containing at
least Ti and/or Zr, O and F and, further containing SiO.sub.2
particles but without containing phosphoric acid ions.
[0030] According to the present invention, there is provided a
surface-treated metal material having, formed on the surface of a
metal base member, a surface-treating layer (A) that contains
inorganic components and an organic surface-treating layer (B) that
contains organic components, the inorganic surface-treating layer
(A) containing M (M is Ti and/or Zr), O and F.
[0031] In the surface-treated metal material according to a third
aspect of the invention, it is desired that:
1. The inorganic surface-treating layer (A) contains no phosphoric
acid ion; 2. The atomic ratio of P and M (M is Ti and/or Zr)
contained in the most surface portion of the inorganic
surface-treating layer (A) is 0.ltoreq.P/M<0.6; 3. The atomic
ratio of 0 and M (M is Ti and/or Zr) contained in the most surface
portion of the inorganic surface-treating layer (A) is
1<O/M<10; 4. The atomic ratio of F and M (M is Ti and/or Zr)
contained in the most surface portion of the inorganic
surface-treating layer (A) is 0.1<F/M<2.5; 5. The inorganic
surface-treating layer (A) contains SiO.sub.2 particles; 6. The
organic surface-treating layer (B) is a silane coupling agent
treating, layer containing Si in an amount of 0.8 to 30 mg/m.sup.2;
and 7. The organic surface-treating layer (B) is an organic
surface-treating layer comprising a phenol-type water-soluble
organic compound.
[0032] According to the present invention, there is provided a
method of treating the surfaces of a metal base member by forming
an inorganic coating on the surfaces of the metal base member by
the cathodic treatment in an aqueous solution containing Ti and F,
and having a phosphoric acid ion concentration calculated as
PO.sub.4 of smaller than 0.003 mols/liter.
[0033] According to a first method of treating the surfaces of the
invention, it is desired that:
1. The aqueous solution contains Zr; 2. The aqueous solution
contains M (M is Ti or Ti and Zr) in an amount of 0.010 to 0.050
mols/liter and F in an amount of 0.03 to 0.35 mols/liter as bath
concentrations; 3. The aqueous solution contains water-dispersing
silica; and 4. The cathodic treatment is intermittently
conducted.
[0034] According to the present invention, further, there is
provided a method of treating the surfaces of a metal base member
by forming an inorganic coating on the surfaces, of the metal base
member by the cathodic treatment in an aqueous solution containing
Zr, F and water-dispersing silica, and having a phosphoric acid ion
concentration calculated as PO.sub.4 of smaller than 0.003
mols/liter.
[0035] According to a second method of treating the surfaces of the
invention, it is desired that:
1. The aqueous solution contains Zr in an amount of 0.010 to 0.050
mols/liter and F in an amount of 0.03 to 0.35 mols/liter as bath
concentrations; and 2, The cathodic treatment is intermittently
conducted. According to the present invention, there is further
[0036] provided a surface-treated metal material having, formed on
the surface of a metal base member (excluding the case When the
metal base member is Al), an inorganic surface-treating layer that
contains at least Al and D.
[0037] In the surface-treated metal material according to a fourth
aspect of the present invention, it is desired that:
1. The inorganic surface-treating layer contains a hydroxide of
aluminum or an oxyhydroxide thereof; 2. the inorganic
surface-treating layer contains at least one of Zr or Ti; 3. The
atomic ratio of 0 and M (M is Al or Al and at least one of Ti or
Zr) contained in the most surface portion of the inorganic
surface-treating layer is 0.1<O/M<5.5; 4. The atomic ratio of
F and M (M is Al or Al and at least one of Ti or Zr) contained in
the most surface portion of the inorganic surface-treating layer is
F/M<2.5; 5. The atomic ratio of (P+S) and M (M is Al or Al and
at least one of Ti or Zr) contained in the most surface portion of
the inorganic surface-treating layer is (P+S)/M<0.25; 6. The
inorganic surface-treating layer has a thickness, calculated as a
weight film thickness of Al, of 5 to 100 mg/m.sup.2; 7. The metal
base member is a surface-treated steel sheet having a plated layer
containing one or more of tin, nickel, zinc and iron; 8. The metal
base member has a surface exposure ratio of chief elements of
smaller than 5%; 9. An organic surface treating layer comprising
chiefly a silane coupling agent is formed in an amount calculated
as Si of 0.8 to 30 mg/m.sup.2 on the inorganic surface-treating
layer; and 10. An organic surface-treating layer comprising chiefly
a phenol-type water-soluble organic compound is formed on the
inorganic surface-treating layer.
[0038] According to the present invention, there is further
provided a surface-treated metal material having an inorganic
surface-treating layer formed on the surface of a metal base member
relying upon the precipitation from an aqueous solution by cathodic
electrolysis, the inorganic surf ace-treating layer containing at
least Al, O and F, and the atomic ratio of F and M (M is Al or Al
and at least one of Ti or Zr) contained in the most surface portion
of the inorganic surface-treating layer being 0.1<F/M.
[0039] According to the present invention, there is further
provided a method of treating the surfaces of a metal base member
by forming a coating containing a hydroxide of aluminum or an
oxyhydroxide thereof on the surface of the metal base member by the
cathodic treatment in an aqueous solution having an Al ion
concentration in a range of 0.001 to 0.05 mols/liter. According to
the third method of treating the surfaces, it is desired that the
aqueous solution contains F ions.
[0040] According to the present invention, further, there is
provided a resin-coated metal material obtained by coating at least
one surface of a surface-treated metal material with an organic
resin, the surface-treated metal material having, formed on the
surface of a metal base member, an inorganic surface-treating layer
containing Ti and/or Al, O and F in the resin-coated metal material
of the first aspect, the inorganic surface-treating layer may
further contain Zr.
[0041] According to the present invention, there is further
provided a resin-coated metal material obtained by coating at least
one surface of a surface-treated metal material with an organic
resin, the surface-treated metal material having an inorganic
surface-treating layer containing at least any one of Ti, Zr or Al,
as well as 0 and F, and having an organic surface-treating layer
comprising chiefly a silane coupling agent formed in an amount,
calculated the amount of Si, of 0.8 to 30 mg/m.sup.2 on the
inorganic surface-treating layer or having an organic
surface-treating layer comprising chiefly a phenol-type
water-soluble organic compound formed on the inorganic
surface-treating layer.
[0042] According to the present invention, there are provided a
metal can and a can lid formed by using the above resin-coated
metal material.
[0043] According to the formation treatment and the anodic
oxidation treatment which are the conventional methods of treating
the surfaces of metal materials, sulfuric acid ions and phosphoric
acid ions tend to be contained in the film due to the mechanism of
forming the coating, and become constituent components in the
formation treatment. It has been known that anions having large
ionic radii such as anions in the film and, particularly,
phosphoric acid ions tend to elute out under high-temperature and
high-humidity conditions such as in the retort sterilization
treatment. Anions that elute out from the coating cause a decrease
in the close adhesion and adhesive property of the resin coating
formed on the surface-treated metal material.
[0044] According to the present invention, the amount of ions,
particularly, phosphoric acid ions and sulfuric acid ions in the
Inorganic surface-treating layer is controlled, or the atomic ratio
of (P+S)/(Ti+Zr+Al) is controlled to effectively suppress the
elution of anions from the treated coating even when subjected to
the retort sterilization or even when preserved under
high-temperature and high-humidity conditions. This effectively
prevents a decrease in the close adhesion and adhesive property of
the resin coating.
[0045] In the surface-treated metal material of the present
invention, further, the inorganic surface-treating layer contains M
(where M is at least any one of Ti, Zr or Al), O and F as chief
constituent components making it possible to maintain the surface
state of the treated layer and to maintain stability on the surface
even under high-temperature and high-humidity environmental
conditions. As a result, the corrosion resistance is maintained
while suppressing a decrease in the close adhesion or adhesive
property of the resin coating.
[0046] That is, when the inorganic surface-treating layer contains
M and O as Chief constituent components but does not contain F, it
is presumed that the treating film has a structure MOx(OH)y.
[0047] Under high-temperature and high-humidity conditions,
however, the hydroxyl groups are likely to be hydrated inducing a
change in the structure of the treating layer to adversely affect
various properties. When F is contained in a suitable amount,
however, the hydroxyl groups are at least partly substituted with F
to form a stable structure like MOx (OH) y-zFz, suppressing a
change in the structure of the treating layer in a high-temperature
and high-humidity environment and maintaining further improved
stability on the surface.
[0048] According to the present invention, if the most surface
portion of the inorganic surface-treating layer is analyzed by the
X-ray photoelectric spectrometry (XPS) that will be described
later, peaks N1s or F1s, S1s and P1s are often detected. This means
the presence of anionic components such as of nitric acid,
fluorine, sulfuric acid and phosphoric acid. From the results of
analysis, it has been known that phosphoric acid ions and sulfuric
acid ions are easily taken in by the coating components and,
particularly, phosphoric acid is present in large amounts. In
preparing the treating bath, therefore, it is desired to give
attention such as decreasing the ratio of the phosphoric acid-type
agent and mixing other agents. According to the present invention
as described above, phosphoric acid ions and sulfuric acid ions
which are anions having large ionic radii are controlled to
effectively suppress the elution of ions from the treated coating
even when subjected to the retort sterilization or preserved under
high-temperature and high-humidity conditions and, therefore,
effectively preventing a decrease in the close adhesion or adhesive
property of the resin coating.
[0049] In the surface-treated metal material of the present
invention, further, it is desired that an organic surface-treating
layer (B) and, particularly, an organic surface-treating layer
(B-1) comprising chiefly a phenol-type water-soluble organic
compound or a silane coupling agent treating layer (B-2) containing
Si in an amount of 0.8 to 30 mg/m.sup.2, is formed on the inorganic
surface-treating layer (A).
[0050] The above inorganic surface-treating layer contributes
chiefly to improving the corrosion resistance of the metal material
while the organic surface-treating layer contributes chiefly to
improving the close adhesion to the organic coating such as of a
polyester resin. When these surface-treating layers are laminated
in this order, excellent close adhesion to the organic resin
coating and corrosion resistance are exhibited even when the metal
can is subjected to severe working such as necking or riveting of
the can lid.
[0051] When a container is formed by using the resin-coated metal
material which has the silane coupling agent layer formed on the
surface of the metal material and a polyester film formed on the
phenol-type organic surface-treating layer, the most conspicuous
effect is that in the step of heat-setting after forming, the
silane coupling agent layer and the phenol-type organic
surface-treating layer become compatible again with the polyester
making it possible to obtain a re-adhering effect. That is, though
the closely adhering force in the interface of the polyester and
the metal drops due to the forming, the silane coupling agent layer
and the phenol-type organic surface-treating layer become
compatible with the polyester in the step of heat-setting without
the need of heating to higher than the melting point of the
polyester, and the closely adhering force is recovered.
[0052] If there is no inorganic surface-treating layer, it is
difficult to suppress a change on the surface of the metal base
member during the retorting, which is not desirable, either, from
the standpoint of corrosion resistance. When there is formed the
organic surface-treating layer comprising chiefly the phenol-type
water-soluble organic compound or the silane coupling agent
treating layer, there are obtained the effect for improving the
close adhesion to the organic coating such as of a polyester resin
and the effect for recovering the closely adhering force owing to
the organic surface-treating layer, and the surface-treated metal
material can be used even if anions having large ionic radii are
eluted out under high-temperature and high-humidity conditions. It
is, however, most desired that the inorganic surface-treating layer
contains none of anions having large ionic radii, such as sulfuric
acid ions or phosphoric ions, as a matter of course.
[0053] In the surface-treated metal material of the invention,
further, the inorganic surface-treating layer may be formed on the
organic surface-treating layer comprising chiefly the phenol-type
water-soluble organic Compound.
[0054] Since the closely adhering force is recovered by the
above-mentioned mechanism, the inorganic surface-treating layer
does not necessarily have to be under the organic surface-treating
layer. Namely, it is considered that when the inorganic
surface-treating layer is formed on the organic surface-treating
layer, the organic surface-treating layer appears through those
portions of the inorganic surface-treating layer that are cracked
during the forming, and the same effect is exhibited at the time of
heat-set. However, if the inorganic surface-treating layer is
formed on the organic surface-treating layer, it becomes necessary
to form by electrolysis the inorganic surface-treating layer that
exhibits excellent close adhesion under wet condition. Therefore,
the electric conduction of the underlying organic surface-treating
layer plays an important role. Concerning this point, the electric
conduction can be easily maintained by forming a thin film by
treating the phenol-type organic surface-treating layer by using a
formation-treating agent such as phosphoric acid or hydrofluoric
acid. The silane coupling agent layer, however, is difficult to
control its thickness and, besides, it fails to exhibit its
performance to a sufficient degree if its thickness is small. As
the organic surface-treating layer formed under the inorganic
surface-treating layer, therefore, there can be suitably used an
organic coating comprising chiefly the phenol-type water-soluble
organic compound.
[0055] In this case, the most surface portion becomes the inorganic
surface-treating layer. The interior of the surface-treating layer
close to the metal base member, however, contains the inorganic
treating layer that has electrolytically precipitated into
defective portions in the organic surface-treating layer or onto
the coating having a small thickness, forming a portion where
organic and inorganic matters are mixed together. Therefore, the
inorganic surface-treating layer covers defective portions in the
organic surface-treating layer contributing to improving the
corrosion resistance of the metal material. If the inorganic
surface-treating layer in the surface is cracked due to the
working, the underlying organic surface-treating layer works to
improve the close adhesion to the organic coating such as of the
polyester resin. Therefore, excellent working adhesion to the
organic resin coating and excellent corrosion resistance of the
inorganic treating layer are exhibited even when the
surface-treated metal material is subjected to the severe working
such as necking of metal Cans and riveting of can lids.
[0056] When the metal cans and can lids are formed by using the
surface-treated metal material of the invention or by using the
resin-coated metal material which is obtained by coating the
surface-treated metal material with an organic resin and,
particularly, a polyester resin, the close working adhesion of the
polyester resin coating is maintained at the highly worked
portions, the corrosion resistance (dent resistance) is improved
despite the polyester resin coating is cracked due to shocks, the
close adhesion is improved during the retort sterilization owing to
the use of the resin-coated metal material which features excellent
close adhesion and corrosion resistance. Besides, the corrosion
caused by permeating ions is suppressed, and the easy-to-open can
lid can be opened in an improved manner.
[0057] According to the method of treating the surfaces of the
present invention, it is important to conduct the cathodic
treatment in an aqueous solution containing Ti and/or Zr and F,
having a phosphoric acid ion concentration calculated as PO.sub.4
of smaller than 0.003 mols/liter and, more preferably, without
containing phosphoric acid ions, or to conduct the cathodic
treatment in an aqueous solution having an Al ion concentration in
a range of 0.001 to 0.05 mols/liter and, preferably, containing F
ions.
[0058] Relying upon the cathodic treatment, the coating can be
quickly formed and the range of controlling the coating thickness
can be greatly broadened, as compared to forming the coating by the
reaction-type method. Thus, it becomes possible to form the coating
that meets the use. According to the conventional formation
treatment based on the chemical reaction of the treating solution
composition, on the other hand, limitation is imposed on the rate
of forming the coating and, therefore, the coating thickness is
limited when the treatment is conducted at an increased rate.
However, the cathodic treatment that utilizes the electrolytic
reaction makes it possible to form the coating at an increased
rate.
[0059] According to the formation treatment and the anodic
oxidation treatment, further, sulfuric acid ions and phosphoric
acid ions tend to be introduced into the coating due to the
mechanism of forming the coating, and turn into constituent
components if the formation treatment is employed making it
difficult to control the amount of anions as described above.
[0060] On the other hand, the cathodic treatment makes it possible
to select various aqueous solutions and to use an aqueous solution
of a fluoride or nitrate and, therefore, to form a coating
controlling the amount of anions having large ionic radii, such as
sulfuric acid ions or phosphoric acid ions.
[0061] According to the formation treatment and anodic oxidation
treatment, further, metal elements of base member that is to be
treated tend to be introduced into the coating due to the mechanism
of forming the coating, which turn into constituent components if
the formation treatment of the reaction type is employed.
Therefore, the composition solution must be studied for every base
member and must often be greatly varied depending upon the cases.
According to the cathodic treatment, on the other hand, the bath
composition may be varied to a minimum degree, and a wide range of
adjustment is realized depending upon the electrolytic conditions
making it possible to treat a variety of base members.
[0062] That is, the present invention can be applied to even such
surface-treated steel sheets as tin-plated steel sheet and
zinc-plated steel sheet in addition to aluminum sheet and steel
sheet. By applying the invention to, for example, the zinc-plated
steel sheet and the tin-plated steel sheet, there can be obtained
such synergistic effects as preventing the corrosion of zinc and
tin, the close adhesion and the corrosion resistance in the
non-chromium surface treatment. The invention is capable of
treating various kinds of base members to provide surface-treated
steel sheets that can be used in a wider range of applications. In
particular, when Al and O are contained as chief components, the
tin oxide film does not grow even when the tin-plated steel sheet
is treated and the color does not change even after the passage of
time from the treatment or even through the heating, and the thus
treated steel sheet can be used for obtaining metal sheets and
metal cans having the above-mentioned properties and for obtaining
can lids, as a matter of course.
[0063] By conducting the same surface treatment, further, it is
allowed to avoid such a problem as galvanic corrosion that is often
reported when different kinds of metal sheets such as aluminum and
steel are used in combination (e.g., a combination of an aluminum
lid and a steel can wall of a metal can).
[0064] According to the method of treating surfaces of a metal
material of the invention, further, it is desired to intermittently
conduct the cathodic treatment. That is, the electrolysis is not
continuously conducted but, instead, a halting time is provided on
the way of electrolysis and the O/M ratio in the surface-treating
layer is controlled to more increase the precipitation efficiency
than when the electrolysis is continuously controlled in order to
accomplish the treatment maintaining a high quality and an
increased rate.
[0065] In the method of treating the surfaces of metal materials of
the invention, further, the electrolysis is conducted while
stirring the bath and, particularly, blowing bubbles containing
oxygen onto the surface of the cathode at a rate of 20 to 300
ml/min-cm to thereby improve uniformity in the coating thickness
and to obtain a uniformly precipitated state over whole cathode
surface without irregularity. That is, by conducting the
electrolysis while blowing Oxygen-containing bubbles onto the
surface of the cathode, local polarization of concentration is
suppressed and, at the same time, the O/M ratio in the
surface-treating layer is controlled by bubbles containing oxygen
to accomplish a uniform treatment maintaining a high quality.
[0066] In the present invention, the inorganic surface-treating
layer contains any one of Ti, Zr or Al as well as 0 and F as chief
constituent components (here, however, F may be arbitrarily used
when the metal material is Al), but may contain any combination of
Ti+Zr, Al+Zr, Al+Ti or Al+Zr+Ti as constituent components. That is,
they are capable of assuming a stable structure like
MOx(GH).sub.y-zFz and can hold a stable surface like Ti, When Ti,
Zr and Al are contained in the above-mentioned combination, the
atomic ratio of P and Ti, atomic ratio of 0 and Ti, atomic ratio of
F and Ti and the concentration of Ti of the aqueous solution in the
cathodic treatment, are all on the basis of the sum of Ti and Zr.
Hereinafter, Ti, Zr and Al contained alone or contained in
combination are often expressed as M,
BRIEF DESCRIPTION OF THE DRAWINGS
[0067] FIG. 1 is a view measuring an inorganic surface-treating
layer of a surface-treated metal material of the invention for its
peaks O1s, Al2p and F1s by XPS;
[0068] FIG. 2 is a view measuring the inorganic surface-treating
layer of the surface-treated metal material of the invention for
its peak Al2p by XPS;
[0069] FIG. 3 is a diagram comparing a peak S is by XPS of the
inorganic surface-treating layer of the surface-treated metal sheet
of the invention with a peak S is by XPS of alumite anodically
oxidized with sulfuric acid;
[0070] FIG. 4 is a diagram measuring the surface of the
surface-treated metal material forming an organic surface-treating
layer of the invention for its peak N1s by XPS;
[0071] FIG. 5 is a view illustrating a sectional structure of a
surface-treated metal material of the invention;
[0072] FIG. 6 is a view illustrating another sectional structure of
the surface-treated metal material of the invention;
[0073] FIG. 7 is a view illustrating a further sectional structure
of the surface-treated metal material of the invention;
[0074] FIG. 8 is a view Illustrating a still further sectional
structure of the surface-treated metal material of the
invention;
[0075] FIG. 9 is a diagram illustrating a relationship between the
total electrolysis time and the weight film thickness of Ti;
[0076] FIG. 10 is a diagram Illustrating a relationship between the
total electrolysis time and the weight film thickness of Zr;
[0077] FIG. 11 is a diagram illustrating a relationship between the
total electrolysis time and the weight film thickness of Al;
[0078] FIG. 12 is a view illustrating a sectional structure of a
resin-coated metal material of the invention;
[0079] FIG. 13 is a view illustrating another sectional Structure
of the resin-coated metal material of the invention;
[0080] FIG. 14 is a side view illustrating a metal can of the
invention;
[0081] FIG. 15 is a top view of an easy-to-open can lid of the
invention; and
[0082] FIG. 16 is a sectional view of the easy-to-open can lid
shown in FIG. 15.
BEST MODE FOR CARRYING OUT THE INVENTION
(Surface-Treated Metal Materials)
[0083] <Inorganic surface-treating layers containing at least
one of Ti or Zr>
[0084] In the surface-treated metal material containing at least
one of Ti or Zr of the invention as described above, one of the
important features is that the inorganic surface-treating layer of
the surface-treated metal material does not contain phosphoric
acid. In the surf ace-treated metal material of the present
invention as will become obvious from the results of Examples
appearing later, no peak P2p due to phosphoric acid is recognized
from the inorganic surface-treating layer as measured by using an
X-ray photoelectric spectrometer (Examples 1 to 7, 10 to 13, 15 and
16).
[0085] In the surface-treated metal material of the invention,
further, an important feature resides in that an atomic ratio of P
and M (M is Ti and/or Zr) contained in the most surface portion of
the inorganic surface-treating layer of the surface-treated metal
material is in a range of 0.ltoreq.P/M<0.6 and, more preferably,
0.ltoreq.P/M<0.1, If P/M is not smaller than the above range,
the coating contains much phosphoric acid or P as impurity
component, and the close adhesion is not obtained to a sufficient
degree.
[0086] It is, further, desired that the inorganic surface-treating
layer of the surface-treated metal material of the invention
contains Ti and/or Zr, O and F as chief constituent components and,
particularly, the surface layer has a value O/M (M is Ti and/or Zr)
in a range of 1 to 10 and, particularly, 1 to 5 in terms of an
atomic ratio If the value O/M is smaller than the above range, it
becomes difficult to form the coating. If the value O/M exceeds the
above range, on the other hand, the close adhesion is not obtained
to a sufficient degree.
[0087] In the surface-treated metal material of the present
invention, further, it is desired that a value of F/M (M is Ti
and/or Zr) contained in the most surface portion of the inorganic
surface-treating layer of the surface-treated metal material is in
a range of 0.1 to 2.5 and, particularly, 0.5 to 2.0 in terms of an
atomic ratio. If the value F/M is smaller than the above range,
stable structures like TiOx (OH) y-zFz and ZrOx (OH) y-zFz
described above are not assumed, and the adhesive property
decreases in a high-temperature and high-humidity environment. If
the value F/M is lager than the above range, on the other hand, the
amount of anions becomes too large relative to M though their ionic
radii may be small and, therefore, the adhesive property
decreases.
[0088] In the surface-treated metal material of the present
invention, further, it is desired that the inorganic
surface-treating layer contains SiO.sub.2 particles. It has
heretofore been known that silica works to form a barrier coating
against the Invasion of corrosive factors and to retard the rate of
corrosion of the steel sheets by holding the corrosive environment
on the alkali side. In the present invention, further,
water-dispersing silica is contained in the inorganic
surface-treating, layer so as to be bonded to oxygen atoms in the
inorganic surface-treating layer and to stay therein as a
chemically stable amorphous silicon oxide. Thus, a dense mesh
structure of siloxane bonds can be formed in the inorganic
surface-treating layer making it possible to form a stable
coating.
[0089] When SiO.sub.2 particles are contained in the inorganic
surface-treating layer, it is desired that the surface covering
ratio of Si contained in the most surface portion of the inorganic
surface-treating layer of the surface-treated metal material is in
a range of 0.10 to 30% and, particularly, 15 to 30% in terms of an
atomic ratio. If the surface covering ratio of Si is smaller than
the above range, it becomes difficult to form the coating. If the
atomic concentration of Si exceeds the above range, on the other
hand, the effect of forming the coating maintaining stability is
not obtained to a sufficient degree despite the water-dispersing
silica is blended.
[0090] Concerning the surface covering ratio of Si, principal
elements serving as constituent components are measured by XPS like
the measurement of the atomic ratio, and the atomic concentration
of Si2p of when the whole components are set to be 100% is defined
to be the surface covering ratio. Here, however, the concentration
must be found after the contaminated layer is lightly removed by Ar
sputtering until the atomic concentration of C becomes not larger
than 10% like in the case of measuring the atomic ratio.
[0091] The atomic ratios of P/M, O/M and F/M can be found from the
atomic concentrations obtained by using an analytical software by
measuring peaks P2p, D1s, F1s, Ti3d and Zr3d by XPS. In the
silica-dispersed samples, however, a dense silica film is formed on
the most surface portion. To find the atomic ratio of O/M (M is Ti
and/or Zr), therefore, a peak Si2p is measured at the same time, a
concentration of O corresponding to SiO.sub.2 is found from the
atomic concentration of Si, the atomic concentrations of elements
are calculated again by excluding the SiO.sub.2 component from the
whole components, and the atomic ratio of O/M (M is Ti and/or Zr)
must be found again.
[0092] The surface-treated metal material used for the measurement
is analyzed for its surface in its form if the surface thereof is
clean if the organic resin has been adhered or melt-adhered, the
surface-treated metal material is immersed in boiled hydrogen
peroxide water for several minutes to remove the organic resin
layer.
[0093] As for a sample which is not clean or a sample from which
the organic resin layer is removed as described above, the layer of
C due to organic matters is subjected to the Ar sputtering to
lightly remove the contaminated layer until the atomic
concentration of C becomes net larger than 10% with respect to when
the sum of principal elements such as C, O, F and M (M is Ti and/or
Zr) is set to be 100% and, thereafter, the ratios P/M, O/M and F/M
can be found. Further, after the background is removed, the peak
areas may be found concerning the elements P, O, F and M (M is Ti
and/or Zr) by an established method and, thereafter, the atomic
concentrations of the elements are found by using relative
sensitivity coefficients of the measuring device to thereby find
P/M, O/M and F/M by calculation.
[0094] It is desired that the film thickness is from 5 to 300
mg/m.sup.2 in terms of the weight film thickness of M (M is Ti or
Ti and Zr). If the film thickness is smaller than 5 mg/m.sup.2, it
becomes difficult to form a uniform coating and the covering ratio
is not sufficient. If the film thickness exceeds 300 mg/m.sup.2,
the adhesive property decreases through the working and is not
desirable.
[0095] The film thickness of M (M is Ti and/or Zr) is determined by
using a fluorescent X-ray analyzer placed in the market. First, a
calibration curve representing a relationship between the film
thickness of Ti and the X-ray intensity of Ti is formed from a
plurality of samples of which the weight film thicknesses of Ti
have been known. Thereafter, the X-ray intensity of Ti measured by
using an unknown sample is converted into a weight film thickness
based on the calibration curve. If Zr alone is contained, too, a
calibration curve of Zr is formed in the same manner and from which
the weight film thickness is calculated. Or, if Zr is contained
together with Ti, the weight film thicknesses of Ti and Zr are
added up together.
[0096] In the surface-treated metal material of the present
invention, when the metal base material to be treated is an
aluminum alloy-coated or aluminum-coated steel sheet which is
subject to be easily scratched, fine particles of sizes of 10 to
10.0 nm may be precipitated on the surfaces to cover the surfaces
of the metal material. The fine particles are considered to be fine
oxide particles of chiefly M (M is Ti or Ti and Zr) which work to
reform the surfaces of aluminum by cathodic electrolysis without
requiring any particular pretreatment offering an effect of
improving the scratch resistance and the wear resistance.
<Inorganic Surf Ace-Treating Layer Containing Al>
[0097] In the surface-treated metal material containing Al of the
present invention as described above, one of the important features
is that the inorganic surface-treating layer of the surface-treated
metal material contains at least Al and O and, more desirably,
contains F, too.
[0098] FIG. 1 shows a peak 2 of O1s, a peak 3 of Al2p and a peak 4
of F1s of the inorganic surface-treating layer 1 containing Al and
O formed by the cathodic electrolysis according to the invention as
measured by using an X-ray photoelectric spectrometer (XPS). Here,
the inorganic surface-treating layer contains F in addition to Al
and O.
[0099] Another important feature is that the surface-treated metal
material contains a hydroxide or an oxyhydroxide of aluminum.
[0100] Described below are examples of the inorganic
surface-treating layers containing a hydroxide or an oxyhydroxide
of aluminum of the invention. First, the surface of the inorganic
surface-treating layer is measured by XPS for its O1s, Al2p and C1s
due to contamination of the sample, to find peaks 11 and 12 of O1s
and Al2p as shown in FIG. 1. Next, bound energy positions 111 and
121 of O1s and Al2p are so corrected that the bound energy position
of C1s due to contamination of the sample becomes constant to
thereby find normal bound energy positions.
[0101] By using the samples of steel sheets plated with tin in an
amount of 1.3 g/m.sup.2, ref low-treated, and coated with inorganic
surface-treating layers maintaining weight film thicknesses of Al
of 30, 40 and 80 mg/m.sup.2 and the samples of an alumina sintered
body and a rolled aluminum sheet as comparative examples, the bound
energy positions of O1s and Al2p were found by the above method.
Among them, the sample of Al 40 mg/m.sup.2 was cathodically
electrolyzed by using an aluminum nitrate bath while other samples
were cathodically electrolyzed by using an aluminum sulfate bath.
As for the comparative examples, the alumina sintered body is
Al.sub.2O.sub.3 and it is considered that the surfaces of the
rolled aluminum sheet are turning into an aluminum oxide. Here, in
order to avoid the effect of adsorbed water, the comparative
samples were heat-treated at 300.degree. C. for one hour prior to
taking measurements. The results were as shown in Table 1. The
bound energy positions have been corrected by using a peak of C1s
due to contamination of the sample. Table 1.
TABLE-US-00001 TABLE 1 Bound energy measured by XPS O1s (eV) Al2p
(eV) Materials of Al 30 mg/m.sup.2 532.1 74.9 the invention
Materials of Al 40 mg/m.sup.2 531.8 75.4 the invention Materials of
Al 80 mg/m.sup.2 532.3 75.0 the invention Comparative Alumina
sintred 531.5 74.4 materials body Comparative Rolled Al sheet 531.7
74.5 materials
[0102] As shown in Table 1, the materials of the present invention
have O1s which is higher by 0.1 to 0.8 eV than that of the
comparative samples, and have Al2p which is shifted toward the high
energy side by 0.4 to 1.0 eV, from which it is learned that the
materials of the present invention do not contain an oxide but
contain a hydroxide or an oxyhydroxide.
[0103] In the surface-treated metal material containing Al of the
present invention, further, an important feature is that the atomic
ratio of 0 and M (M is Al or Al and at least one of Ti and Zr)
contained in the most surface portion of the inorganic
surface-treating layer is 1<O/M<5.5 and, more preferably,
1<O/M<3.5. It is difficult to form the inorganic
surface-treating film having O/M which is not larger than the above
range, i.e., which is not larger than 1.
[0104] If anionic components of large ionic radii are not almost
contained, the ratio O/M lies in a range of 1<O/M<2.5. If the
ratio is lying in a range of 2.5.ltoreq.O/M<3.5, it is
considered that anionic components such as phosphoric acid and
sulfuric acid having large ionic radii are contained in the coating
to some extent and if the ratio is lying in a range of
3.5.ltoreq.O/M<5.5, the anionic components are contained in
considerable amounts. Therefore, to maintain the adhesive property
after the retort treatment when the ratio is lying in the range of
3.5.ltoreq.O/M<5.5, it is desired to form the organic
surface-treating layer such as the coupling agent treating layer on
the inorganic surface-treating layer. Further, if 5.5<O/M which
is beyond the above range, it is considered that the base material
components are oxidized in addition to the elements included in M.
That is, the tin layer on the surface of the tin sheet is oxidized
eventually causing O/M to increase, in this case, the cohesive
force is weak since the surface of tin itself has been oxidized,
and the close adhesion is not obtained to a sufficient degree
despite the organic surface-treating layer is provided.
[0105] In the surface-treated metal material of the present
invention, further, it is desired that an atomic ratio of F and M
(M is Al or Al and at least one of Ti and Zr) contained in the most
surface portion of the inorganic surface-treating layer is smaller
than 2.5 and, particularly, is not larger than 2.0.
[0106] If F/M is not smaller than 2.5, the amount of anions becomes
too great relative to M though F may have a small ionic radius,
causing a decrease in the close adhesion.
[0107] The atomic ratios O/M and F/M can be found from the atomic
concentrations obtained by using an analytical software by
measuring peaks present in the surface such as of C1s, O1s, F1s,
Al2p, Ti3d and Zr3d by XPS.
[0108] The surface-treated metal material used for the measurement
is analyzed for its surface in its form if the surface thereof is
clean. If the organic resin has been adhered or melt-adhered, the
surface-treated metal material is immersed in boiled hydrogen
peroxide water for several minutes to remove the organic resin
layer.
[0109] As for a sample which is not clean or a sample from which
the organic resin layer is removed as described above, the
contaminated layer is lightly removed by Ar sputtering until the
atomic concentration of C1s becomes not larger than 0.101 with
respect to the sum of principal elements constituting the surface
such as C, O, F, Al, Zr, Ti and metal base material elements, that
is set to be 100% and, thereafter, the atomic ratios O/M and F/M
are found. Further, after the background is removed, the peak areas
may be found concerning the elements O, F and Al, Zr and Ti by an
established method and, thereafter, the atomic concentrations of
the elements are found by using relative sensitivity coefficients
of the measuring device to thereby find O/M and F/M by
calculation.
[0110] FIG. 2 shows a peak 2 of Al2p, A range surrounded by a
reference line 21 of background and a peak 22 is a peak area 23.
Here, attention must be given in drawing the background since the
atomic ratio varies depending upon the manner of drawing the
background, as a matter of course.
[0111] In its most desired form, further, the inorganic
surface-treating layer of the Invention does not contain anionic
component having large ionic radius, such as phosphoric acid or
sulfuric acid like the inorganic surface-treating layer comprising
chiefly Ti and Zr. One of the features of the invention is that the
atomic ratio of (P+S) and M (M is Al or Al and at least one of Ti
or Zr) contained in the most surface portion of the inorganic
surface-treating layer is controlled to be (P+S)/M<0.25 and,
more preferably, (P+S)/M<0.05.
[0112] FIG. 3 compares a peak 31 of S is in the most surface
portion of alumite anodically oxidized with sulfuric acid as
measured by XPS with a peak 32 of S is in the most surface portion
of the inorganic surface-treating layer of the invention.
Similarly, a peak P2p and peaks present in the surface such as C1s,
O1s, F1s, Al2p, Ti3d and Zr3d, are measured, and (P+S)/M is found
from the atomic concentrations obtained by using the analytical
software. In the samples of FIG. 3, a value of (P+S)/M is 0.0 in
the present invention while it is 0.1 with the anodically oxidized
alumite.
[0113] As for the film thickness, it is desired that the weight
film thickness of Al is in a range of 5 to 100 mg/m.sup.2. If the
weight film thickness is smaller than 5 mg/m.sup.2, it becomes
difficult to form a uniform coating and the covering ratio is not
sufficient. If the weight film thickness exceeds 100 mg/m.sup.2,
the close adhesion decreases through the working and is not
desirable.
[0114] As for the method of measuring the weight film thickness,
the film thickness can be determined by using a fluorescent X-ray
analyzer placed in the market when Al is not the chief component of
the metal base member, in this case, first, a calibration curve
representing a relationship between the weight film thickness Of Al
and the X-ray intensity of Al is formed from a plurality of samples
of which the weight film thicknesses of Al have been known.
Thereafter, the X-ray intensity of Al measured by using an unknown
sample is converted into a weight film thickness based on the
calibration curve.
[0115] When the metal base member chiefly comprises Al, the metal
base member is dissolved in an acid to extract the inorganic
surface-treating layer. Thereafter, by using an energy
dispersion-type X-ray analyzer attached to a transmission-type
electron microscope, the weight film thickness is found from the
calibration curve formed by using the X-ray intensity and a
standard sample.
[0116] If the inorganic surface-treating layer contains at least
one of Zr or Ti in addition to Al, the respective elements have
different densities. It is, therefore, desired that the total
weight film thickness of Al, Zr and Ti lies in a range of 5 to 300
mg/m.sup.2,
[0117] in the present invention, further, when the metal base
member having a plated layer is to be treated for its surfaces, it
is desired that the surface exposure ratio of chief elements in the
metal base member is less than 5% and, preferably, less than
3%.
[0118] If the exposure ratio of chief elements in the metal base
member is larger than the above value, the corrosion resistance and
the close adhesion are not satisfactory. In particular, in treating
the surfaces on where metal tin is present, such as of tin plate,
steel sheet thinly plated with tin or steel sheet very thinly
plated with tin, if the surface exposure ratio of tin is not
smaller than 5%, problems arouse concerning the corrosion
resistance, close adhesion, resistance against acids and
discoloration with the passage of time, exhibiting inferior
appearance. The surface exposure ratio can be found from an atomic
concentration obtained by using the analytical software by
measuring peaks of principal elements present in the surface, such
as C1s, P2p, O1s, F1s, S is, Al2p, Ti3d, Zr3d, Sn2d and Fe2p by
using XPS. Hers, however, the peak Fe2p may often be overlapped on
the peak Sn. In this case, the peaks must be separated.
<Organic Surface-Treating Layers>
[0119] In the surface-treated metal material of the present
invention, the organic-surface treating layer present together with
the inorganic surface-treating layer is an organic coating
comprising chiefly an organic component and, particularly, (i) a
silane coupling agent treating layer containing Si in an amount of
0.8 to 30 mg/m.sup.2 or (ii) a layer comprising chiefly a
phenol-type water-soluble organic compound.
(i) Silane Coupling Agent Treating Layer.
[0120] In the surface-treated metal material of the present
invention, it is particularly desired that a silane coupling agent
treating layer containing Si in an amount of 0.8 to 30 mg/m.sup.2
is further formed on the inorganic surface-treating layer.
[0121] The silane coupling agent forming the silane coupling agent
treating layer has a reaction group that chemically bonds to a
thermoplastic polyester resin and a reaction group that chemically
bonds to the inorganic surface-treating layer. There can be used an
organosilane having a reaction group such as amino group, epoxy
group, methacryloxy group or mercapto group, and a hydrolyzing
alkoxyl group such as methoxy group or ethoxy group, or a silane
having an organic substituent such as methyl group, phenyl group,
epoxy group or mercapto group, and a hydrolyzing alkoxy group.
[0122] Concrete examples of the silane coupling agent that can be
preferably used in the invention include .gamma.-APS
(.gamma.-aminopropyltrimethoxysilane, .gamma.-GPS
(.gamma.-glycidoxypropyltrimethoxysilane), BTSPA
(bistrimethoxysilylpropylaminosilane), and N-.beta. (aminoethyl)
.gamma.-aminopropyltrimethoxysilane.
[0123] It is desired that the silane coupling agent treating layer
contains Si in an amount of 0.8 to 30 mg/m.sup.2 and, particularly,
3 to 15 mg/m.sup.2. If the amount of Si is smaller than the above
range, the effect of the organic surface-treating layer is poor,
i.e., the effect is poor for improving the corrosion resistance and
close adhesion. If the amount of Si is not smaller than the above
range, the unreacted silane coupling agent undergoes the
self-condensation, and the close work adhesion and corrosion
resistance are not obtained to a sufficient degree.
[0124] It is particularly desired that the organic surface-treating
layer which is the silane coupling agent treating layer is formed
on the Inorganic surface-treating layer that contains SiO.sub.2
particles. In this case, it is desired that the surface covering
ratio of Si contained in the most surface portion of the inorganic
surface-treating layer of the surface-treated metal material is in
a range of 0.10 to 30% and, particularly, 15 to 30% in terms of an
atomic ratio. If the surface covering ratio of Si is smaller than
the above range, it becomes difficult to form the coating. If the
atomic concentration of Si exceeds the above range, on the other
hand, the effect of forming the coating maintaining stability is
not obtained to a sufficient degree despite the water-dispersing
silica is blended.
[0125] Concerning the surface covering ratio of Si, principal
elements serving as constituent components are measured by XPS like
the measurement of the atomic ratio, and the atomic concentration
of Si2p of when the whole components are set to be 100% is defined
to be the surface covering ratio. Here, however, the concentration
must be found after the contaminating layer is lightly removed by
Ar sputtering until the atomic concentration of C becomes not
larger than 10% like in the case of measuring the atomic ratio,
(ii) Layer Comprising Chiefly a Phenol-Type Water-Soluble Organic
Compound.
[0126] In the surface-treated metal material of the present
invention, it is particularly desired that a layer comprising
chiefly a phenol-type water-soluble organic compound is present on
the inorganic surface-treating layer.
[0127] It is desired that the phenol-type water-soluble organic
compound is a phenol resin comprising recurring units represented
by the following formula (1),
##STR00001## [0128] wherein .phi. is a benzene ring, X is a
hydrogen atom or Z represented by the following formula (2),
[0128] ##STR00002## [0129] wherein R.sub.1 and R.sub.2 are alkyl
groups with not more than 10 carbon atoms or hydroxyalkyl groups
with not more than 10 carbon atoms, the introduction ratio of the
group Z is desirable as repetition units of phenoric resin being
0.2 to 1.0 per a benzene ring.
[0130] Another example of the phenol-type water-soluble organic
compound is a tannin. The tannin is also called tannic acid and
stands for aromatic Compounds of complex structures having a
phenolic hydroxyl group in general.
[0131] As the tannin, there can be exemplified hamamelitannin,
persimmon tannin, tea tannin, Chinese tannin, Turkish tannin,
myrobalan tannin, divi-divi tannin, algarobillatannin, valonia
tannin and catechin tannin. It is desired that the tannin has a
number average molecular weight of not smaller than 200.
[0132] In the organic surface-treating layer comprising chiefly the
phenol-type water-soluble organic compound, it is desired that the
organic surface-treating layer contains the phenol-type
water-soluble organic compound in an amount of 3 to 75 mg/m.sup.2
and, particularly, 6 to 30 mg/m.sup.2 calculated as carbon atoms.
If the amount is smaller than the above range, the organic
surface-treating coating exhibits Inferior adhesion. If the amount
is larger than the above range, on the other hand, the thickness of
the organic surface-treating coating becomes unnecessarily large
deteriorating the close adhesion and corrosion resistance.
[0133] Further, the organic surface-treating layer comprising
chiefly the phenol-type water-soluble organic compound may be an
organic/Inorganic composite layer formed by using an organic
compound comprising chiefly carbon and a surface-treating agent
containing a phosphorous compound and a zirconium or titanium
compound.
[0134] In the surface-treated metal material forming the organic
surface-treating layer of the invention, further, it is desired
that the most surface layer contains N.
[0135] FIG. 4 shows a peak 41 N1s of the most surface layer of the
surfaces-treated metal material having the silane coupling agent
treating layer formed on the surface thereof as measured by XPS. As
shown in FIG. 4, N is detected, N is similarly detected from the
phenol-type water-soluble organic compound, too.
<Metal Base Members>
[0136] As the metal base member used in the invention, there can be
used various surface-treated steel sheets and light metal sheets
such as of aluminum. As the surface-treated steel sheet, there can
be used a cold rolled steel sheet that is annealed followed by the
secondary cold rolling and one or two or more kinds of surface
treatments such as zinc plating, tin plating, nickel plating and
aluminum plating. There can be further used an aluminum-clad steel
sheet.
[0137] The plated layer may comprise a metal layer containing one
or more of tin, nickel, zinc, iron and aluminum. Or, the plated
layer may comprise a metal layer containing one or more of tin,
nickel, zinc, iron and aluminum and an alloy layer containing two
or more of tin, nickel, zinc, aluminum and iron. Or, the plated
layer may comprise an alloy layer only containing two or more of
tin, nickel, zinc, iron and aluminum.
[0138] A metal is formed by plating or cladding on the surface side
of the metal base member in order to improve various properties
such as corrosion resistance, wear resistance and electric
conduction of the metal located on the center side, generally and
in most of the cases, to improve the corrosion resistance. As the
light metal sheet, an aluminum alloy is used in addition to the
so-called pure aluminum. There is no particular limitation on the
thickness of the metal plate. Though it may vary depending upon the
kind of the metal, use of the container and the size thereof, the
metal sheet, usually, has a thickness of 0.10 to 0.50 mm. In
particular, the surface-treated steel sheet has a thickness of 0.10
to 0.30 mm and the light metal sheet has a thickness of 0.15 to
0.40 mm.
<Structures of the Surface-Treated Metal Materials>
[0139] FIGS. 5 to 7 are sectional views illustrating the surf
ace-treated metal materials of the present invention. The
surface-treated metal material 5 shown in FIG. 5 includes a metal
base member 51 and Inorganic surface-treating layers 52 formed on
the surfaces of the base member and containing M fat least any one
of Ti, Zr or Al), O and F as essential components (here, however, F
may be arbitrarily contained when the metal base member is Al). In
an example of FIG. 6, organic surface-treating layers 53 comprising
chiefly organic components are formed on the inorganic
surface-treating layers 52 of FIG. 5.
[0140] The surface-treated metal material 5 shown in FIG. 7 is the
same as that of FIG. 5 with respect to having the inorganic
surface-treating layer 52 containing M (at least any one of Ti, Zr
or Al), O and F as essential components (here, however, F is
arbitrarily contained when the metal base member is Al), but the
metal base member 51 is constituted by a metal material 51a and
metal-plated layers 51b. The metal-plated layers 51b covering the
metal material 51a occupying most of the base member 51 are those
that play the role of enhancing the corrosion resistance of the
metal material 51a as will be described later,
[0141] The surface-treated metal material S shown in FIG. 8 has
inorganic surface-treating layers 52 containing M (at least any one
of Ti, Zr or Al), O and F as essential components (here, however, F
is arbitrarily contained when the metal base member is Al) formed
on the metal base member 51, the inorganic surface-treating layers
52 containing SiO.sub.2 particles 55,
(Method of Treating the Surfaces)
<Method of Treating the Surface of the Inorganic
Surface-Treating Layers Containing Ti and Zr>
[0142] In the method of treating the surfaces of a metal material
of the invention, it is an important feature to conduct the
cathodic treatment in an aqueous solution containing Ti and/or Zr
and F, having a phosphoric acid ion concentration calculated as
PO.sub.4 of smaller than 0.003 mols/liter and, preferably, without
containing phosphoric acid.
[0143] As described above, the cathodic treatment makes it possible
to greatly broaden the range of controlling the weight film
thickness of Ti and/or Zr per a unit time as compared to the
conventional formation-treated coatings, and makes it possible to
form a coating that meets the use.
[0144] In the method of treating the surfaces of the invention,
further, it is desired to conduct the cathodic treatment
intermittently, i.e., to intermittently conduct the electrolysis by
providing a halting time on the way of electrolysis and repeating
many times a cycle of flowing and halting an electric current in an
aqueous solution with stirring. FIGS. 9 and 10 illustrate
relationships between the total electrolysis time which is the sum
of current-flowing time and halting time and the weight film
thickness of Ti or the weight film thickness of Zr. As will be
obvious from FIGS. 9 and 10, it will be learned that the weight
film thickness of Ti or Zr grows faster when the cathodic
electrolysis is intermittently conducted than when the cathodic
electrolysis is continuously conducted.
[0145] This is because, if the electrolysis is continuously
conducted, the concentration is polarized near the cathode to
impair the precipitation. Upon intermittently conducting the
electrolysis, however, ions such as of Ti, O, OH and F are supplied
to near the cathode due to the stirring effect while the
electrolysis is being discontinued, and a film loosely formed on
the cathode, i.e., a film having a large ratio 0/Ti or O/Zr is
removed. As a result, the weight film thickness of Ti or the weight
film thickness of Zr grows faster, and a film of a high quality is
provided.
[0146] Though there is no limitation, the cycle of flowing the
current and halting the current is such that the flowing time is
0.1 to 0.8 seconds while the halting time is 0.3 to 1.5 seconds,
and 2 to 10 cycles are conducted.
[0147] It is desired that the aqueous solution used for the method
of treating the surfaces of the invention has a bath concentration,
calculated as M (M is Ti or Ti and Zr), in a range of 0.010 to
0.0.50 mols/liter and, particularly, 0.015 to 0.035 mols/liter. In
the cathodic treatment, the electrolysis locally concentrates when
the metal sheet having an oxide film densely formed on the surface
thereof is treated, making it difficult to form a uniform coating
unless a particular pretreatment is effected. According to the
present invention, however, the electrolytic treatment is conducted
in a bath of a low concentration in order to form a
surface-treating film which is as uniform as possible without
effecting any particular pretreatment. That is, if the bath
concentration is higher than the above range, nuclei are locally
formed and where the electrolysis concentrates predominantly,
resulting in the formation of a coating lacking, however,
uniformity. If the bath concentration is lower than the above
range, on the other hand, the electric conduction in the bath is
low and an increased amount of electric power is required for the
treatment, which is not desirable.
[0148] It is desired that the aqueous solution used for the surface
treatment has a pH of 3.0 to 8.0 and, more preferably, 3.5 to 6.5.
As a Ti agent used for the treating solution, there can be used
potassium titanium fluoride K.sub.2TiF.sub.6, ammonium titanium
fluoride (NH.sub.4).sub.2TiF.sub.6, and sodium titanium fluoride
Na.sub.2TiF.sub.6.
[0149] As the Zr agent, there can be used potassium zirconium
fluoride KZrf.sub.6, ammonium zirconium fluoride
(NH.sub.4).sub.2ZrF.sup.6 and ammonium zirconium carbonate solution
(NH.sub.4).sub.2ZrO(CO.sub.3).sub.2.
[0150] Further, the titanium ions, zirconium ions, and fluorine
ions can be supplied using different agents. As the Ti agent, there
can be used potassium titanium oxalate dihydrate
K.sub.2TiO(C.sub.2O.sub.4).sub.2.2H.sub.2O, titanium chloride (III)
solution TiCl.sub.3, and titanium chloride (IV) solution
TiCl.sub.4. As the Zr agent, there cay be used zirconium oxynitrate
ZrO(NO.sub.3).sub.2 and zirconium oxyacetate
ZrO(CH.sub.3COO).sub.2. As the F agent, there can be used sodium
fluoride NaF, potassium fluoride KF and ammonium fluoride
NH.sub.4F.
[0151] As for the F ion concentration in the bath, it is desired
that the F concentration is in a range of 0.03 mols/liter to 0.35
mols/liter. If the fluorine ion concentration is lower than the
above range, a gel-like substance is formed on the surface of the
metal which is the cathode impairing the handling during the
continuous production and causing properties in the surface to lose
the stability under high-temperature and high-humidity conditions
with the passage of time, which is not desirable. If the bath
concentration is higher than the above range, the precipitation
efficiency is impaired and precipitates form in the bath, which is
not desirable.
[0152] It is particularly desired that the aqueous solution used
for the surface treatment is blended with the water-dispersing
silica. The water-dispersing silica is for improving the corrosion
resistance and film formability as described above. Though there is
no particular limitation, there can be exemplified spherical
silica, chain-like silica and aluminum-modified silica. Concrete
examples of the spherical silica are colloidal silica such as
Snowtex N and Snowtex UP (both produced by Nissan Kagaku Kogyo Co.)
and fumed silica such as Aerosil (produced by Nihon Aerosil Co.),
As the chain-like silica, there can be used a silica gel such as
Snowtex PS (produced by Nissan Kagaku Kogyo Co.). As the
aluminum-modified silica, there can be used a commercially
available silica gel such as Adelite AT-20A (produced by Asahi
Denka Kogyo Co.). It is desired that the silica with which the
treating solution is blended has a particle size in a range of 4 to
80 nm and, particularly, 4 to 30 nm. Particles smaller than this
range are difficult to obtain whereas particles larger than this
range cause cracking during the working and are not desirable. The
blended amount of silica in the coating is desirably in a range of
3 to 100 mg/m.sup.2 and, particularly, 20 to 80 mg/m.sup.2
calculated as the amount of Si. If the amount is smaller than this
range, the effect of being blended with silica is small. If the
amount is larger than the above range, the film itself lacks
cohesive force, which is not desirable.
[0153] As required, further, nitric acid ions, peroxide and
complexing agent may be added to the aqueous solution used for the
surface treatment.
[0154] The nitric acid ions are effective in maintaining stability
in the state of precipitation when the electrolysis is conducted
for extended periods of time, and nitric acid, sodium nitrate,
potassium nitrate and ammonium nitrate can be used as ion sources.
A peroxide generates oxygen in an aqueous solution, is effective in
suppressing the polarization of concentration near the surface of
the cathode and is, particularly, effective when the bath is poorly
stirred. As the peroxide, there can be used hydrogen peroxide,
ammonium peroxodisulfate, potassium peroxodisulfate, sodium
peroxoborate, sodium peroxocarbonate or sodium peroxodisulfate. The
complexing agent works to suppress the formation of precipitates in
the bath, and there can be used ethylenediamine tetraacetate,
ethylenediamine sodium tetraacetate, citric acid, sodium citrate,
boric acid, nitrilo triacetate, nitrilosodium triacetate,
cyclohexanediamine tetraacetate and glycin. Too high concentrations
of nitric acid ions, peroxide and complexing agent tend to impair
the efficiency of precipitation. It is desired that the
concentrations of the nitric acid ions, peroxide and complexing
agent are not higher than 0.2 mols/liter, respectively.
[0155] The metal base member is pretreated according to an
established method, i.e., effecting the dewaxing, washing with
water and, as required, washing with an acid and washing with water
to clean the surfaces, subjecting the metal base member to the
cathodic electrolysis relying on the intermittent electrolytic
method in an aqueous solution maintained at a temperature of 30 to
65.degree. C. with stirring at a current density of 0.1 to 50
A/dm.sup.2 repeating the cycle of flowing a current and halting a
current for a total electrolysis time of 0.3 to 20 seconds and,
finally, effecting the washing with water to thereby obtain a
desirable surface structure.
[0156] As the opposing electrode sheet corresponding to the anode
side, a titanium sheet coated with iridium oxide is favorably used.
Desired conditions for the opposing electrode sheet are that the
opposing electrode material does not dissolve in the treating
solution during the electrolysis and that it works as an insoluble
anode having a small oxygen overvoltage.
<Method of Treating the Surface of the Inorganic
Surface-Treating Layer Containing Al>
[0157] In the method of treating, the surfaces of the metal sheet
of the invention, an important feature resides in the cathodic
treatment in an aqueous solution having an Al ion concentration in
a range of 0.001 to 0.05 mols/litter.
[0158] In the cathodic treatment, if electrolysis locally
concentrates, the coating becomes nonuniform like in the method of
treating the surfaces of the inorganic surface-treating layer
containing Ti and Zr. Therefore, attention must be given such that
the potential distribution becomes uniform. In particular, the
electrolysis locally concentrates when the metal sheet having an
oxide film densely formed on the surface thereof is treated or when
the metal sheet that easily dissolves in an acidic region is
treated, making it difficult to form a uniform coating. When, for
example, an aluminum sheet is to be treated, therefore, a
particular pretreatment is effected in many cases, such as a
treatment with the zincate.
[0159] According to the present invention, the electrolytic
treatment is conducted in a bath of a low concentration in order to
form a surface-treating film which is as uniform as possible
without effecting any particular pretreatment. That is, if the bath
concentration is higher than the above range, the concentration
tends to be polarized and the electrolysis concentrates
predominantly in the portions where the polarization resistance is
low, resulting in the formation of a coating lacking, however,
uniformity. If the bath concentration is lower than the above
range, on the other hand, the electric conduction in the bath is
low and an increased amount of electric power is required for the
treatment, which is not desirable.
[0160] In the method of treating the surfaces of the present
invention, it is desired that the aqueous solution further contains
F ions in addition to Al ions.
[0161] FIG. 11 compares the thicknesses of the Al-precipitated
films by using a bath without containing F ion and a bath
containing F ions in an amount of 0.024 mols/litter and conducting
the electrolysis under the same conditions by using a tin-plated
steel sheet as a cathode. The abscissa represents the total
electrolysis time which is the sum of the halting time and the
current-flowing time of when the electrolysis is intermittently
conducted by repeating the cycle of flowing the current and halting
the current a plural number of times. It will be learned from FIG.
11 that the Al film is formed faster when the F ions are
contained.
[0162] In the method of treating the surfaces of the invention, if
the current density is not lower than about 5 A/dm2, it is desired
to intermittently execute the cathodic treatment, i.e., to
intermittently execute the electrolysis by providing a halting time
on the way of electrolysis and repeating the cycle of flowing the
current and halting the current a plural number of times in an
aqueous solution with stirring though the range of current density
cannot be clearly specified since it varies depending upon the bath
concentration, bath composition and the material of the base
member. If the electrolysis continues, a loose film of a large O/Al
ratio precipitates like a gel on the surface of the cathode causing
the concentration to be polarized and impairing the formation of a
film of good quality. By intermittently conducting the
electrolysis, on the other hand, ions such as of Al, O, OH and F
are fed to the vicinity of the cathode due to the effect of
stirring while the electrolysis is halting, and the loose film,
i.e., the film having a large O/Al ratio formed on the cathode is
removed by stirring. As a result, the weight film thickness of Al
is quickly formed to provide a film of higher quality.
[0163] Though not limited thereto only, it is desired that the
cycle of flowing the current and halting the current is such that
the current-flowing time is 0.1 to 0.8 seconds and the halting time
is 0.3 to 1.5 seconds, and 2 to 30 cycles are carried out.
[0164] When the electrolysis is conducted at a low current density
of, for example, about 0.5 A/dm.sup.2, there is no difference in
the precipitation efficiency between the continuous electrolysis
and the intermittent electrolysis or the precipitation efficiency
is better in the case of the continuous electrolysis. When the
current density is low, the rate of precipitation is small and the
concentration is little polarized making no difference between the
continuous electrolysis and the intermittent electrolysis or,
conversely, a high precipitation efficiency is accomplished in the
case of the continuous electrolysis.
[0165] The aqueous solution used for the surface treatment has a pH
of 2.0 to 7.0 and, more preferably, a pH of 2.3 to 6.0, As the Al
agent used for the treating solution, there can be used aluminum
nitrate Al(NO.sub.3).sub.3.9H.sub.2O, as well as aluminum potassium
sulfate AlK(SO.sub.4).sub.2.12H.sub.2O, aluminum sulfate
Al2(SO.sub.4).sub.3. 13H.sub.2O, aluminum dihydrogenphosphate
solution Al(H.sub.2PO.sub.4).sub.3, aluminum phosphate AlPO.sub.4,
and aluminum lactate [CH.sub.3CH(OH)COO].sub.3Al.
[0166] When Zr and Ti are used together with Al, there can be used
the Ti agent, Zr agent or the F agent exemplified concerning the
method of treating the surfaces of the inorganic surface-treating
layer containing Ti and Zr.
[0167] Even when the Al agent is used without including Zr or Ti
agent, it is desired that the aqueous solution contains F from the
standpoint of precipitation efficiency. When Zr or Ti agent is used
together with Al, in particular, it is desired that the aqueous
solution contains F at a concentration in a range of 0.03
mols/liter to 0.35 mols/liter. If the fluorine ion concentration is
lower than the above range, the precipitation efficiency is low,
and properties on the surface lose stability in a high-temperature
and high-humidity environment with the passage of time, which is
not desirable. If the fluorine ion concentration is higher than the
above range, the precipitation efficiency is impaired and, besides,
precipitates form in the bath, which is not desirable.
[0168] Further, the aqueous solution used for the surface treatment
may contain, as required, nitric acid ions, peroxide and complexing
agent, described above concerning the method of treating the
surfaces of the inorganic surface-treating layer containing Ti and
Zr.
[0169] The method of pre-treating the metal base member and the
conditions for the opposing electrode sheet corresponding to the
anode side may be the same as those described above concerning the
method of treating the surfaces of the inorganic surf ace-treating
layer containing Ti and Zr.
<Formation of the Organic Coating>
[0170] According to the method of treating the surfaces of the
Invention, it is particularly desired to form the above inorganic
coating and, thereafter, apply the phenol-type water-soluble
organic compound or the silane coupling agent, followed by drying
to form an organic coating.
[0171] To form the organic coating on the inorganic
surface-treating layer, the above phenol-type water-soluble organic
compound or the silane coupling agent solution is applied onto the
inorganic surface-treating layer, or the surface-treated metal
material having the inorganic surface-treating layer formed thereon
is immersed in the phenol-type water-soluble organic compound or in
the silane coupling agent solution and, thereafter, an excess of
the solution is removed by using squeeze rolls, followed by heating
and drying under a condition of a temperature of 80 to 180.degree.
C.
(Resin-Coated Metal Materials)
[0172] The resin-coated metal material of the invention is coated
with an organic layer and, particularly, with a layer of a
polyester resin on at least one surface of the surface-treated
metal material. The surface-treated metal material features close
adhesion to the resin coating and excellent adhesive property and,
therefore, features excellent corrosion resistance and dent
resistance.
[0173] Referring to FIG. 12 which is a sectional view of a
resin-coated metal material of the invention, if the inner side of
the container (right side in the drawing) is viewed, the
resin-coated metal material 5 has a multi-layer structure including
a metal base member 51, an inorganic surface-treating layer 52
formed on the surface of the base member and containing M (M is at
least any one of Ti, Zr or Al), O and F as essential components
(here, however, F is arbitrarily contained when the metal base
member is Al), an organic surface-treating layer 53 formed on the
inorganic surface-treating layer 52, and a polyester resin coating
layer 54 formed thereon. In the example of FIG. 12, the container
has an outer resin protection layer 55 formed via the inorganic
surface-treating layer 52 on the outer surface side (left side In
the drawing). The outer resin protection layer 55 may be formed of
the same polyester resin as the polyester resin coating layer 54 or
may be formed of a different polyester resin, or may be formed of a
different resin.
[0174] Referring to FIG. 13 illustrating another resin-coated metal
material, the resin-coated metal material 5 is the same as the one
shown in FIG. 12 with regard to that it has the surface-treating
layer 52 containing M (M is at least any one of Ti, Zr or Al), O
and F as essential components (here, however, F is arbitrarily
contained when the metal base member is Al), an organic
surface-treating layer 53 formed on the base member 51 which is on
the inner surface side of the container, the polyester resin layer
54 and the outer resin protection layer 55 formed on the outer
side. Here, however, the base member 51 is constituted by a metal
sheet 51a and metal plated layers 51b, and the polyester resin
layer 54 has a laminated structure of a surface polyester resin
layer 54a and an underlying polyester resin layer 54b, It was
mentioned already that the metal plated layers 51b covering the
metal sheet 51a which occupies most of the base member 51 play the
role of enhancing the corrosion resistance of the metal sheet 51a.
It was further mentioned already that the underlying polyester
resin layer 54b is the one that excellently adheres to the metal
base member while the surface polyester resin layer 54a has
excellent resistance against the content.
(Organic Resin Coating Layer)
[0175] In the resin-coated metal material of the present invention,
there is no particular limitation on the organic resin formed on
the metal sheet, and there can be used various thermoplastic resins
and thermosetting or thermoplastic resins.
[0176] Organic resins may be olefin-type resin films such as
polyethylene, polypropylene, ethylene/propylene copolymer,
ethylene/vinyl acetate copolymer, ethylene/acrylic ester copolymer
and ionomer; polyester films such as polybutylene terephthalate and
the like; polyamide films such as nylon 6, nylon 6,6, nylon 1.1 and
nylon 12; or thermoplastic resin films such as polyvinyl chloride
film and polyvinylene chloride film, which may not be drawn or may
be biaxially drawn. As the adhesive used for laminating the layers,
there can be used an urethane-type adhesive, epoxy-type adhesive,
acid-modified olefin resin-type adhesive, copolyamide-type adhesive
or copolyester-type adhesive (thickness: 0.1 to 5.0 .mu.m).
Further, a thermosetting coating material may be applied onto the
side of the surface-treated metal material or onto the film side
maintaining a thickness of 0.05 to 2 .mu.m so as to work as an
adhesive.
[0177] As the organic resin, there can be used thermoplastic or
thermosetting coating materials such as modified epoxy coating
materials like phenol-epoxy and amino-epoxy; and synthetic
rubber-type coating materials like vinyl chloride/vinyl acetate
copolymer, saponified product of a vinyl chloride/vinyl acetate
copolymer, vinyl chloride/vinyl acetate/maleic anhydride copolymer,
epoxy-modified, epoxyamino-modified or epoxyphenol-modified vinyl
coating material, or modified vinyl coating material, acrylic
coating material and styrene/butadiene copolymer, which may be used
alone or in a combination of two or more kinds.
[0178] Among them, the polyester resin is most desired as a
material for containers. As the polyester resin, there can be
exemplified a thermoplastic polyester derived from an alcohol
component comprising chiefly ethylene glycol or butylene glycol and
an acid component such as an aromatic dibasic acid like
terephthalic acid, isophthalic acid or naphthalenedicarboxylic
acid.
[0179] As the polyester, a polyethylene terephthalate itself can be
used as a matter of course. From the standpoint of shock resistance
and workability, however, it is desired to lower the highest
crystallization degree of the film that can be reached. For this
purpose, it is desired to introduce a copolymerized ester unit
other than the ethylene terephthalate into the polyester. It is
particularly desired to use a copolymerized polyester comprising
chiefly ethylene terephthalate units or butylene terephthalate
units containing other ester units in small amounts and having a
melting point of 210 to 252.degree. C. The homopolyethylene
terephthalate has a melting point of, generally, 255 to 265.degree.
C.
[0180] Generally, it is desired that not less than 70 mol % and,
particularly, not less than 75 mol % of the dibasic acid component
in the copolymerized polyester comprises a terephthalic acid
component, not less than 70 mol % and, particularly, not less than
75 mol % of the diol component comprises ethylene glycol or
butylene glycol, and 1 to 30 mol % and, particularly, 5 to 25 mol %
of the dibasic acid component comprises a dibasic acid component
other than the terephthalic acid.
[0181] As the dibasic acid other than the terephthalic acid, there
can be exemplified aromatic dicarboxylic acids such as isophthalic
acid, phthalic acid and naphthalene dicarboxylic acid; alicyclic
dicarboxylic acids such as cyclohexanedicarboxylic acid; aliphatic
dicarboxylic acids such as succinic acid, adipic acid, sebacic acid
and dodecanedioic acid; which may be used in one kind or in a
combination of two or more kinds. As the diol components other than
the ethylene glycol or the butylene glycol, there can be
exemplified propylene glycol, diethylene glycol, 1,6-hexylene
glycol, cyclohexane dimethanol and ethylene oxide adduct of
bisphenol A, which may be used in one kind or in a combination of
two or more kinds. It is desired that the combination of these
comonomers is such that the melting point of the copolymerized
polyester lies in the above range, as a matter of course.
[0182] In order to improve melt-fluidizing properties at the time
of forming, the polyester can contain at least one kind of
branching or crosslinking component selected from the group
consisting of multibasic acids which are trifunctional or more
highly functional and polyhydric alcohols. It is desired that these
branching or crosslinking components are contained in amounts of
not larger than 3.0 mol % and, preferably, in a range of 0.05 to
3.0 mol %.
[0183] As the trifunctional or more highly functional polybasic
acid and polyhydric alcohol, there can be exemplified such
polybasic acids as trimellitic acid, pyromellitic acid,
hemimellitic acid, 1,1,2,2-ethanetetracarboxylic acid,
1,1,2-ethanetricarboxylic acid, 1,3,5-pentanetricarboxylic acid,
1,2,3,4-cyclopentanetetracarboxylic acid,
biphenyl-3,4,3',4'-tetracarboxylic acid, and such polyhydric
alcohols as pentaerythritol, glycerol, trimethylolpropane,
1,2,6-hexanetriol, sorbitol, and
1,1,4,4-tetrakis(hydroxymethyl)cyclohexane.
[0184] In the resin-coated metal material of the present invention,
the polyester resin which can be particularly preferably used for
the material for producing cans or can lids is represented by a
polyethylene terephthalate/isophthalate containing an isophthalic
acid component in an amount of 5 to 25 mol % and a
polyethylene/cyclohexylenedimethylene terephthalate containing a
cyclohexanedimethanol component in an amount of 0.1 to 10 mol
%.
[0185] The homopolyester or the copolymerized polyester must have a
molecular weight in a range for forming films, and the solvent has
an intrinsic viscosity [.eta.] in a range of 0.5 to 1-5 and,
particularly, 0.6 to 1.5 as measured by using a
phenol/tetrachloroethane mixed solvent.
[0186] The polyester resin layer used in the present invention may
be formed using the above polyester or the copolyester alone, may
be formed by using a blend of two or more kinds of polyesters or
copolyesters, or may be formed by using a blend of the polyester or
the copolyester and other thermoplastic resin. As the blend of two
or more kinds of polyesters or copolyesters, there can be
exemplified combinations of two or more kinds of polyethylene
terephthalate, polybutylene terephthalate, polyethylene
terephthalate/isophthalate, and
polyethylene/cyclohexylenedimethylene terephthalate, to which only,
however, the invention is not limited.
[0187] As other thermoplastic resins with which the polyester can
be blended, there can be exemplified an ethylene-type monomer,
thermoplastic elastomer, polyarylate and polycarbonate. Use of at
least one of these reforming resin components makes it possible to
further improve the resistance against high temperatures and high
humidities, and the shock resistance. Usually, the reforming resin
component is used in an amount of up to 50 parts by weight and,
particularly preferably, in an amount of 5 to 35 parts by weight
per 100 parts by weight of the polyester.
[0188] As the ethylene-type polymer, there can be exemplified low-,
intermediate- and high-density polyethylenes, linear low-density
polyethylene, linear ultra-low-density polyethylene,
ethylene/propylene copolymer, ethylene/butene-1 copolymer,
ethylene/propylene/butene-1 copolymer, ethylene/vinyl acetate
copolymer, ionicaily crosslinked olefin copolymer (ionomer) and
ethylene/acrylic acid ester copolymer. Among them, the ionomer is
preferred. As a base polymer of the ionomer, there can be used an
ethylene/(meth)acrylic acid copolymer and ethylene/(meth) acrylic
acid ester/(meth) acrylic acid copolymer. As the ion species, there
can be used Na, K, Zn, etc. As the thermoplastic elastomer, there
can be used styrene/butadiene/styrene block copolymer,
styrene/isoprene/styrene block copolymer, hydrogenated
styrene/butadiene/styrene block copolymer and hydrogenated
Styrene/isoprene/styrene block copolymer.
[0189] The polyarylate is defined as a polyester derived from a
divalent phenol and a dibasic acid. As the divalent phenol,
bisphenols can be used, such as 2,2'-bis(4-hydroxyphenyl)propane
(bisphenol A), 2,2'-bis(4-hydroxyphenyl)butane (bisphenol B),
1,1'-bis(4-hydroxyphenyl)ethane, bis(4-hydroxyphenyl)methane
(bisphenol F), 4-hydroxyphenyl ether, and p-(4-hydroxy)phenol.
Among them, bisphenol A and bisphenol B are preferred. As the
dibasic acid, there can be used terephthalic acid, isophthalic
acid, 2,2-(4-carboxyphenyl)propane, 4,4'-dicarboxydiphenyl ether,
and 4,4'-dicarboxybenzophenone. The polyacrylate may be a
hpmopolymer or a copolymer derived from the above monomer
components.
[0190] Or, the polyarylate may be a copolymer of an aliphatic
glycol and an ester unit derived from the dibasic acid in a range
in which the essential properties thereof are not impaired. The
polyacrylates are available as U-Series or AX-series of U-polymers
produced by Unitika Co., as Arde ID-100 produced by UCC Co., as APE
produced by Bayer Co., as Durel produced by Hoechst Co., as Arylon
produced by Du Pont Co., and as NAP resin produced by Kanegafuchi
Kagaku Co.
[0191] The polycarbonate is a carbonic acid ester resin derived
from bicyclic and dihydric phenols and phosgene, and features a
high glass transition point and heat resistance. The polycarbonate
is desirably a polycarbonate derived from bisphenols such as
2,2'-bis(4-hydroxyphenyl)propane (bisphenol A),
2,2'-bis(4-hydroxyphenyl)butane (bisphenol B),
1,1'-bis(4-hydroxyphenyl) ethane, bis(4-hydroxyphenyl)methane
(bisphenol F), 1,1-bis(4-hydroxyphenyl)cyclohexane,
1,1-bis(4-hydroxyphenyl)cyclopentane,
1,1-bis(4-hydroxyphenyl)-1-phenylmethane,
1,1-bis(4-hydroxyphenyl)-1-phenylethane and
1,2-bis(4-hydroxyphenyl)ethane.
[0192] The polyester resin layer used in the invention may be a
single resin layer or a multiplicity of resin layers formed by the
simultaneous extrusion. Use of the multiplicity of polyester resin
layers is advantageous since a polyester resin of a composition
having excellent adhesive property can be selected for the
underlying layer, i.e., can be selected on the side of the
surface-treated metal material, and a polyester resin of a
composition having excellent resistance against the content, i.e.,
having excellent anti-extracting property and property for not
adsorbing flavor components can be selected for the surface
layer.
[0193] Examples of the multiplicity of polyester resin layers
include, being expressed as the surface layer/lower layer,
polyethylene terephthalate/polyethylene terephthalate.
isophthalate, polyethylene terephthalate/polyethylene.
cyclohexylenedimethylene terephthalate, polyethylene terephthalate
containing isophthalate in a small amount.
isophthalate/polyethylene terephthalate containing isophthalate in
a large amount.isophthalate, polyethylene
terephthalate.isophthalate/[a blend of polyethylene
terephthalate.isophthalate and polybutylene terephthalate.
adipate], to which only, however, the invention is not limited. The
thickness ratio of the surface layer:lower layer is desirably in a
range of 5:95 to 95:5.
[0194] The polyester resin layer can be blended with known blending
agents for resins, such as an anti-blocking agent like amorphous
silica, inorganic filler, various antistatic agents, lubricant,
anti-oxidizing agent, and ultraviolet-ray absorber according to
known recipe.
[0195] Among them, it is desired to use a tocopherol (vitamin E).
It has heretofore been known that the tocopherol works as an
anti-oxidizing agent preventing a decrease in the molecular weight
due to degradation when the polyester resin is heat-treated to
improve dent resistance. In particular, if the polyester
composition of the polyester resin blended with the ethylene-type
polymer as a reforming resin component is, further, blended with
the tocopherol, there are obtained such effects that not only the
dent resistance is improved but also corrosion is prevented from
taking place through the cracks, and the corrosion resistance is
conspicuously improved even in case the coating is cracked as a
result of being subjected to severe conditions such as of the
retort sterilization and the hot bender.
[0196] It is desired that the tocopherol is blended in an amount of
0.0.5 to 3% by weight and, particularly, 0.1 to 2% by weight.
[0197] in the present invention, the thickness of the organic resin
layer is desirably in a range of 3 to 50 .mu.m and, particularly, 5
to 40 .mu.m. If the thickness is smaller than the above range, the
corrosion resistance is not sufficient. If the thickness is larger
than the above range, on the other hand, a problem arouses
concerning the workability,
(Production of the Resin-Coated Metal Material)
[0198] In the present invention, the polyester coating layer can be
formed on the surface-treated metal material by any means such as
extrusion coating method, cast film hot-adhesion method or
biaxially drawn film hot-adhesion method. In the case of the
extrusion coating method, the surface-treated metal material is
coated with the polyester resin that is extruded in a molten state,
and the polyester resin is heat-adhered thereto. That is, the
polyester resin is melt-kneaded in an extruder, extruded from a
T-die in the form of a thin film, and the extruded molten resin
film is passed together with the surface-treated metal material
through a pair of laminating rolls so as to be pressed and
integrated together while being cooled, followed by quick
quenching. When the multiplicity of polyester resin layers are to
be extrusion-coated, there are used an extruder for the surface
resin layer and an extruder for the lower resin layer. The resin
flows from the extruders meet together in a multi-layer die.
Thereafter, the extrusion-coating is effected in the same manner as
the case of the single resin layer. Further, the surface-treated
metal material is vertically passed through the pair of laminating
rollers, and molten resin webs are supplied to both sides thereof
in order to form coatings of the polyester resin on both surfaces
of the base member.
[0199] Concretely speaking, the resin-coated metal material is
produced by the extrusion coating method in a manner as described
below. The surface-treated metal material (hereinafter often simply
called metal sheet) is, as required, preheated through a heating
device and is fed to a nipping position between the pair of
laminating rolls. The polyester resin, on the other hand, is
extruded into the form of thin film through the die head of the
extruder, and is fed to among the laminating rolls and the metal
sheet so as to be press-adhered onto the metal sheet by the
laminating rolls. The laminating rolls are maintained at a
predetermined temperature and work to press-adhere thin films of a
thermoplastic resin such as the polyester onto the metal sheet to
heat-adhere them together and, thereafter, work to cool them from
both sides to obtain a resin-coated metal material. Generally, the
thin-coated metal material that is formed is further guided into a
water vessel for cooling in order to quickly quench it to prevent
crystallization due to the heat.
[0200] According to the extrusion coating method, the polyester
resin layers are suppressed to a crystallization degree of a low
level which is different from the amorphous density by not more
than 0.0-5 g/cm.sup.3 as a result of selecting the resin
composition and due to being quickly quenched by the rolls and by
the cooling vessel, and a sufficient degree of workability is
guaranteed in a subsequent working for producing cans and lids. The
quick quenching operation is not limited to the above example only,
and may be such that the cooling water is sprayed onto the
resin-coated metal material that is formed to quickly quench the
laminated sheet.
[0201] The polyester resin is heat-adhered to the metal sheet
relying upon a thermal capacity possessed by the molten resin
layers and upon a thermal capacity possessed by the metal sheet.
The heating temperature (T1) of the metal sheet is, usually,
90.degree. C. to 290.degree. C. and, particularly, 100.degree. C.
to 280.degree. C. while the temperature of the laminating rolls is
suitably in a range of 10.degree. C. to 150.degree. C.
[0202] The resin-coated metal material of the invention can be
further produced by heat-adhering a polyester resin film formed in
advance by a T-die method or an inflation film-forming method onto
the metal sheet. As the film, there can be used an undrawn film
obtained by quickly quenching the extruded film by a cast forming
method or a biaxially drawn film obtained by biaxially drawing the
above film successively or simultaneously at a drawing temperature
and heat-setting the film after it has been drawn.
[0203] In the present invention, a variety of constitutions can be
employed in addition to the above layer constitution. It is
allowable, as a matter of course, to provide a known primer for
adhesion between the surface-treated metal material and the
polyester layer though it is not particularly needed when the
organic surface-treating layer is formed. The adhesive primer
exhibits excellent adhesion property to both the metal blank and
the film. As the primer coating material featuring excellent
adhesion property and corrosion resistance, there can be
exemplified a phenol epoxy-type coating material comprising a
resol-type phenol-aldehyde resin derived from various phenols and a
formaldehyde, and a bisphenol-type epoxy resin, containing the
phenol resin and the epoxy resin at a weight ratio of 50:50 to 1:99
and, particularly, at a weight ratio of 40:60 to 5:95. The primer
layer for adhesion is, usually, formed maintaining a thickness of
0.01 to 10 .mu.m. The primer layer for adhesion may be formed on
the metal blank in advance or may be formed on the polyester
film.
(Metal can and its Production)
[0204] The metal can of the present invention may be produced by
any production method so far as it is formed by using the above
resin-coated metal material. The metal can may be a three-piece can
having seams in the side surface but is, usually, desired to be a
seamless can (two-piece can). The seamless can is produced through
known means such as draw/redraw working, bend-elongation
(stretching) based on draw/redraw working, bend-elongation/ironing
working based on the draw/redraw working, or draw-ironing in a
manner that the surface of the surface-treated metal material
coated with the polyester resin becomes the inside of the can. The
seamless can may be a two-piece can used by wrap-seaming the lid
after the neck is formed, or may be a bottle-type can used by
effecting the capping after a multi-step necking work/threading
work. Further, the bottle-type can may be a three-piece can having
a shell lid wrap-seamed at the bottom and having a cap at the upper
part of the can.
[0205] Referring to FIG. 14 showing a seamless can which is a metal
can of the present invention, the seamless can 111 is formed by
draw-ironing the resin-coated metal material, and includes a bottom
portion 112 and a can wall 113. The bottom portion 112 and the can
wall 113 are connected together seamlessly. The bottom portion 112
has a thickness at the central portion thereof substantially the
same as that of the resin-coated metal material that is used, but
the can wall 113 at least partly has a thickness that is reduced to
30% to 70% of the initial sheet thickness due to the working. The
can wall 113 has at an upper part thereof a flange portion 115 for
wrap-seaming with the can lid formed via a single-step or
multi-step neck portion 114.
[0206] As described above, the seamless can is produced by drawing
and ironing. Here, the drawing and the ironing may be
simultaneously executed in one stroke or may be separately executed
in separate strokes.
[0207] According to a preferred method of producing the seamless
can, for example, the resin-coated metal material is cut in a
circular shape, formed into a shallow-drawn cup by drawing using a
drawing die and a drawing punch in combination, and is subjected to
a step of effecting the drawing and the ironing simultaneously in
the same metal mold, the step being repeated a plural number of
times to form a cup having a small diameter and a large height.
According to this forming method, the deformation for reducing the
thickness is effected according to a combination of deformation
(bend-elongation) by the load in the direction of can axis
(direction of height) and deformation (ironing) by the load in the
direction of thickness of the can, and in this order, offering an
advantage of effectively imparting molecular orientation in the
direction of can axis. Thereafter, the cup is subjected to the
doming, heat treatment in order to remove residual distortion in
the coating resin caused by the working, trimming for the open end,
printing on the curved surface, necking and flanging to obtain a
can.
[0208] The metal can of the present invention can toe produced by a
conventional production method such as a draw/ironing method
disclosed in JP-A-4-231120 and a simultaneous draw/ironing method
disclosed in JP-A-9-253772.
(Can Lid and its Production)
[0209] The can lid of the present invention may be produced by any
known method so far as it is formed by using the above-mentioned
resin-coated metal material. Usually, the can lid will be an
easy-to-open can lid of the stay-on-tab type or an easy-to-open can
lid of the full-open type.
[0210] Referring to FIG. 15 which is a top view of the easy-to-open
can lid of the invention and FIG. 15 which is a sectional view
thereof on an enlarged scale, a lid 60 is formed by using the above
resin-coated metal material, has a sealing groove 62 on the outer
circumferential side via a ring-like rim portion (counter-sink) 61
to be fitted to the inner surface of the can wall, and a is formed
on the inside of the ring-like rim portion 61 over the whole
circumference to sectionalize a portion 63 that is to be opened. On
the inside of the portion 63 that is to be opened, there are formed
a recessed panel 65 of nearly a semicircular shape formed by
pushing in nearly the central portion thereof, formed by protruding
the lid member surrounding the recessed panel 65, and a formed by
protruding the lid member toward the outer surface side of the can
lid, and a tab 68 for opening is fixed by riveting by the rivet 67.
The tab 68 for opening has at an end thereof a for opening when it
is pushed and broken and has at the other end thereof a ring 70 for
holding. Near the on the side opposite to the score 64, a score 71
for initiating the breakage is formed being isolated from the score
64.
[0211] To open the lid, the of for opening is held and is lifted
up. Therefore, the for Initiating the breakage breaks, the for
opening of the for opening is pushed down relatively greatly, and
the starts to be partly broken.
[0212] Next, the is pulled up, and the remaining portion of the is
broken over the whole circumference and the lid is easily
opened.
[0213] The lid concretely described above is of the so-called
full-open type. The invention, however, can also be applied to the
easy-to-open lid of the stay-on-tab type, as a matter of
course.
[0214] According to a preferred method of producing the
easy-to-open can lid, the resin-coated metal material is punched
into a circular shape and into the shape of a lid through a step of
press-forming, passed through a lining step where the sealing
groove is lined with a compound followed by drying, passed through
a score-engraving step where the score is engraved from the outer
surface side of the lid so as to reach halfway the metal blank and,
thereafter, a rivet is formed, a tab is attached to the rivet, and
the tab is fixed by riveting to thereby form an easy-to-open can
lid. A suitable example of the easy-to-open can lid has been
disclosed in, for example, JP-A-2000-128168.
EXAMPLES
[0215] Next, the invention will be concretely described to clarify
the effect by way of Examples and Comparative Examples.
[0216] The metal container is placed in the severest environment
from the standpoint of working the surface-treated metal material
or the resin-coated metal material and the corrosion resistance.
Therefore, Examples deal with the metal cans and can lids to which
only, however, the invention is in no way limited, as a matter of
course.
[Preparation of the Treating Baths]
[0217] Treating baths were prepared by so adjusting the
concentrations of titanium ions, zirconium ions and fluorine ions
that the aqueous solutions acquired molar concentrations of Ti, Zr
and F as shown in Table 2. As the titanium agent, however, a
potassium titanium fluoride was used for the treating baths A, B, C
and D, and a potassium titanium oxalate dihydride was used for the
treating baths E and F. As the zirconium agent, a potassium
zirconium fluoride was used for the treating baths B, C and D.
[Formation of the Polyester Films]
[0218] Polyester resins of compositions shown in Table 3 were
melt-extruded from the two extruders through a two-layer T-die, and
were cooled by the cooling rolls. The thus obtained films were
taken up to obtain cast films (a), (b), (c), (d), (e), (f) and (g)
constituted as shown in Table 4.
[Measuring the Surface Atomic Ratios]
[0219] In taking a measurement of surface atomic ratios, the
inorganic surface-treated metal sheets of before being put to the
organic treatment were measured when the organic treatment such as
the treatment with a silane coupling agent or the treatment with a
phenol-type organic compound is to be executed after the inorganic
surface treatment. By using the X-ray photoelectric spectrometer
(XPS), the metal materials after the inorganic surface treatment
were measured for their peaks P2p, O1s, F1s, Ti3d, Zr3d and Al2p
under the following conditions, and the atomic ratios of (P or
P+S)/M, O/M and F/M (M is at least one or more of Ti, Zr and Al)
were found from the atomic concentrations obtained by using an
analytical software. In the case of the silica-dispersed samples,
however, a dense silica film was formed on the surfaces. To find
O/M, therefore, the peak Si2p was also measured simultaneously, the
concentration of O corresponding to SiO.sub.2 was found from the
atomic concentration of Si, the atomic concentrations of the
initial elements were calculated again excluding the SiO.sub.2
component from the whole components, and the atomic ratio of O/M
was found. Further, In the case of the chief element contained in
the surface of the base member, e.g., in the case of the aluminum
alloy base member, Al2p was also measured simultaneously with P2p,
O1s, F1s, Ti3d, Zr3d and Si2p, and the atomic concentration was
used when the contaminated layer was lightly removed by Ar
sputtering until the atomic concentration of C1s has decreased down
to 0.10% or smaller. Concerning the surface exposure ratio, when
the base member was, for example, a tin-plated steel sheet, peaks
of chief elements present in the surface, such as C1s, P2p, O1s,
F1s, S is, Al2p, Ti3d, Zr3d, Sn3d5 and Fe2p were measured, and the
atomic concentration of tin found by using the analytical software
was regarded to be the surface exposure ratio. [0220] Apparatus:
Quantum 2000 manufactured by PHI Co. [0221] Exciting X-ray source:
Al monochrometer 75W-17 kV [0222] Measuring diameter: .phi. 100
.mu.m [0223] Photoelectron take-out angle: 90.degree. (0.degree.
with respect to the normal of the sample) [0224] Analytical
software: MultiPak
[Evaluation of the Adhesive Property]
[0225] The surface-treated metal material was cut into a short
strip of a width of 5 mm and a length of 80 mm, and the cast film
(c) shown in Table 4 was cut into a short strip of a width of 5 mm
and a length of 80 mm. A cut piece of the above polyester film was
held between the two pieces of surface-treated short strips
obtained above, which was heated at 250.degree. C. for 3 seconds
under a pressure of 2.0 kg/cm.sup.2 to obtain a T-peel test piece.
Thereafter, a retort treatment was conducted at 110.degree. C. for
60 minutes. Immediately after the retort treatment, the test piece
was immersed in water, pulled out of water just prior to taking a
measurement by using a tension tester, and was measured for its
adhering strength at a tension speed of 10 mm/min.
Example 1
1. Formation of a Surface-Treated Metal Sheet
[0226] As a metal sheet, an aluminum alloy sheet, JIS 5021H18,
having a thickness of 0.25 mm was pretreated, i.e., treated with a
dewaxing agent 322N8 (produced by Nihon Paint Co.) according to an
established method in a bath maintained at 70.degree. C. for 10
seconds, and was washed with water, immersed in 1% sulfuric acid
maintained at 40.degree. C. for 5 seconds, washed with water and,
then, with pure water. Next, the cathodic electrolysis was
intermittently conducted in the treating bath A shown in Table 2
maintained at a bath temperature of 45.degree. C. with stirring,
using a titanium sheet coated with iridium oxide disposed at a
position maintaining an interelectrode distance of 17 mm as an
anode at a current density of 10 A/dm.sup.2 and flowing the current
for 0.4 seconds and halting the current for 0.6 seconds
repetitively 4 times. The aluminum alloy sheet was immediately
subjected to the after-treatment, i.e., washing with flowing water,
with pure water and drying to obtain a surface-treated aluminum
sheet.
2. Formation of a Resin-Coated Metal Sheet
[0227] From the thus obtained surface-treated metal sheet, a
resin-coated metal sheet for producing lids was formed in a manner
as described below. First, the lower layer side of the cast film
(b) shown in Table 4 was thermally press-adhered onto one surface
of the surface-treated metal sheet that has been heated at a
temperature of 250.degree. C. by using the laminating rolls, and
was immediately cooled with water so as to form the coating on one
surface. Next, an epoxyacrylic coating material was applied to the
another one surface of the metal sheet that became the outer
surface side of the lid by roll-coating, and was baked at
185.degree. C. for 10 minutes.
3. Evaluation of the Surface-Treated Metal Plate
[0228] Part of the obtained surface-treated metal sheet was
measured for its weight film thicknesses of Ti and Zr, and surface
atomic ratios and was evaluated for its adhesive property. The
results were as shown in Table 5.
[0229] In Table 5, the adhesive property was evaluated to be
.circleincircle. when a maximum tensile strength was not smaller
than 0.6 kg/5 mm, .largecircle. when the maximum tensile strength
was not smaller than 0.3 kg/5 mm but was smaller than 0.6 kg/5 mm,
and X when the maximum tensile strength was smaller than 0.3 kg/5
mm after the test pieces were exfoliated by more than 10 mm by
using the tension tester.
4. Evaluation of the Openability of Can Lids
[0230] From the obtained resin-coated metal sheet, full-open can
lids of a 301-diameter were formed according to an established
method, wrap-seamed with the can walls filled with water, put to
the retort sterilization treatment at 110.degree. C. for 60
minutes, cooled, and were immediately opened to observe the state
of exfoliation of resin in the opening portions around the score
portions to thereby evaluate the openability of the can lids. The
results were as shown in Table 5.
[0231] In Table 5, the openability of the can lids was evaluated by
observing the feathering around the opening portions, and was
evaluated to be .circleincircle. when the feathering was not
recognized at all, .largecircle. when the feathering was smaller
than 0.5 mm and the resin was not exfoliated, and X when the
feathering was not smaller than 0.5 mm.
Example 2
[0232] The surface was treated, coated with the resin, and the lids
were formed and evaluated in the same manner as in Example 1 but
setting the current density to be 5 A/dm.sup.2 and flowing the
current for 0.6 seconds and halting the current for 0.4 seconds
repetitively 8 times.
Example 3
[0233] The surface was treated, Coated with the resin, and the lids
were formed and evaluated in the same manner as in Example 1 but
using the treating bath B of Table 2 and setting the current
density to be 7 A/dm.sup.2.
Example 4
[0234] The surface was treated, coated with the resin, and the lids
were formed and evaluated in the same manner as in Example 0.1 but
using the treating bath B of Table 2 and setting the current
density to be 5 A/dm.sup.2.
Example 5
[0235] The surface was treated, coated with the resin, and the lids
were formed and evaluated in the same manner as in Example 1 but
using the treating bath C of Table 2 and setting the current
density to be 14 A/dm.sup.2.
Example 6
[0236] The surface was treated, coated with the resin, and the lids
were formed and evaluated in the same manner as in Example 1 but
using the treating bath D of Table 2 and setting the current
density to be 6 A/dm.sup.2.
Example 7
[0237] The surface was treated, coated with the resin, and the lids
were formed and evaluated in the same manner as in Example 1 but
adding Snowtex C (produced by Nissan Kagaku Kogyo Co.) in an amount
of 60 g/liter to the bath A of Table 2, setting the current density
to be 5 A/dm.sup.2, and flowing the current for 0.6 seconds and
halting the current for 0.4 seconds repetitively 6 times.
Example 8
1. Preparation of a Surface-Treating Agent Comprising Chiefly a
Phenol-Type Water-Soluble Organic Compound
[0238] The following components were used as the surface-treating
agent comprising chiefly the phenol-type water-soluble organic
compound.
TABLE-US-00002 Hydrofluoric acid (HF) 0.01 g/liter 75% Phosphoric
acid (H.sub.3PO.sub.4) 0.20 g/liter 20% zirconium hydrofluoride
(H.sub.2ZrF.sub.6) 1.30 g/litter Solid component of water-soluble
0.40 g/liter polymer of the folowing formula (I)
[0239] That is, a water-soluble polymer which is an aqueous phenol
resin comprising recurring units represented by the formula
(I),
##STR00003## [0240] wherein X is a hydrogen atom or a group Z
represented by the following formula (II),
[0240] ##STR00004## [0241] the group 2 being introduced at a rate
of 0.3 per a benzene ring.
2. Formation of the Surface-Treated Metal Sheet and Evaluation
[0242] The metal sheet was pretreated in the same manner as in
Example 1, and a surface-treating agent comprising chiefly the
phenol-type water-soluble organic compound prepared in 1. above was
sprayed thereon at 40.degree. C. for 20 seconds, followed by
washing with water and, then, with pure water. Thereafter, the
surface was treated, coated with the resin, lids were formed and
evaluated in the same manner as in Example 1 but using the treating
bath A shown in Table 2, setting the current density to be 5
A/dm.sup.2, and flowing the current for 0.6 seconds and halting the
current for 0.4 seconds repetitively 6 times.
Example 9
[0243] The surface was treated, coated with the resin, and the lids
were formed and evaluated in the same manner as in Example 1 but
adding potassium dihydrogenphosphate in an amount of 0.002
mols/liter to the bath A of Table 2 and flowing the Current for 0.6
seconds and halting the current 0.4 seconds repetitively 8
times.
Example 10
[0244] The metal sheet was treated for its surfaces in the same
manner as in Example 7, dipped in an aqueous solution containing 3%
of .gamma.-aminopropyltrimethoxysilane (product name; KBM903
produced by Shin-Etsu Kagaku Kogyo Co.), squeezed by the rolls, and
was dried at 12.01 for one minute to obtain a surface-treated metal
sheet having a silane coupling agent layer of a thickness of 5
mg/m.sup.2 calculated as Si on the inorganic treating layer. In
other respects, the surface was treated and coated with the resin,
and the lids were formed and evaluated in the same manner as in
Example 1, However, the surface atomic ratios were those values
obtained before the organic treatment was effected.
Example 11
[0245] The surface was treated, coated with the resin, and the lids
were formed and evaluated in the same manner as in Example 1 but
adding sodium fluoride in an amount of 0.05 mols/liter to the bath
E of Table 2, setting the current density to be 5 A/dm.sup.2 and
flowing the current for 0.6 seconds and halting the current 0.4
seconds repetitively 8 times,
Comparative Example 1
[0246] The metal sheet was pretreated in the same manner as in
Example 1, a bath was prepared according to an established method
by using a commercially available titanium-type formation-treating
solution (CT-K3795 produced by Nihon Perkalizing Co.) and was
sprayed thereon maintaining a solution temperature of 40.degree. C.
for 15 seconds immediately followed by the after-treatments such as
washing with water, then, with pure water and drying to obtain a
surface-treated aluminum sheet. In other respects, the
surface-treated aluminum sheet was coated with the resin, and the
lids were formed and evaluated in the same manner as in
Example.
Comparative Example 2
[0247] The surface was treated in the same manner as in Example 1
but adjusting the treating bath F of Table 2 with ammonia to
possess a pH of 2.3 and conducting the cathodic treatment at a
current density of 5 A/dm.sup.2 for 60 seconds without stirring.
The obtained coating was removed if it was washed with flowing
water. After the electrolysis, therefore, the surface-treated metal
sheet was calmly immersed in a pool of water and was dried. The
surf ace-treated metal sheet was coated with the resin, and the
lids were formed and evaluated in the same manner as in Example
1.
Comparative Example 3
[0248] The surface was treated in the same manner as in Comparative
Example 2 but adding sodium fluoride in an amount of 0.4 mols/liter
to the bath F of Table 2, setting the current density to be 5
A/dm.sup.2, and flowing the current for 0.6 seconds and halting the
current 0.4 seconds repetitively 4 times. The obtained coating was
removed if it was washed with flowing water. After the
electrolysis, therefore, the surface-treated metal sheet was calmly
immersed in a pool of water and was dried. The surface-treated
metal sheet was coated with the resin, and the lids were formed and
evaluated in the same manner as in Comparative Example 2.
Comparative Example 4
[0249] The surface was treated, coated with the resin, and the lids
were formed and evaluated in the same manner as in Example 1 but
conducting the cathodic electrolysis by adding potassium
dihydrogenphosphate in an amount of 0.005 mols/liter to the bath A
of Table 2, and flowing the current for 0.6 seconds and halting the
current 0.4 seconds repetitively 4 times.
Comparative Example 5
[0250] The metal sheet was treated for its surfaces in the same
manner as in Example 1, dipped in an aqueous solution containing
3.0% of .gamma.-aminopropyltrimethoxysilane (product name: KBM903
produced by Shin-Etsu Kagaku Kogyo Co.), squeezed by the rolls, and
was dried at 120.degree. C. for one minute to obtain a
surface-treated metal sheet having a silane coupling agent layer of
a thickness of 50 mg/m.sup.2 calculated as Si on the inorganic
treating layer. In other respects, the surface was treated and
coated with the resin, and the lids were formed and evaluated in
the same manner as in Example 1. However, the surface atomic ratios
were those values obtained before the organic treatment was
effected.
Example 12
1. Formation of a Surface-Treated Metal Sheet
[0251] As a metal sheet, an aluminum alloy sheet, JIS 3004H19,
having a thickness of 0.26 mm was used. In other respects, the
surface was treated in the same manner as in Example 1.
2. Formation of a Resin-Coated Metal Sheet
[0252] The thus obtained surface-treated metal sheet was, first,
heated at 250.degree. C. The lower layer side of the cast film (b)
shown in Table 4 was thermally press-adhered onto one surface of
the metal sheet and the cast film (a) shown in Table 4 was
thermally press-adhered onto the another one surface that became
the outer surface side of the can by using the laminating rolls so
as to cover the surfaces in a contacted manner. The cast films were
immediately cooled with water to obtain a resin-coated metal
sheet.
3. Formation of a Metal Can
[0253] A paraffin wax was electrostatically applied onto both
surfaces of the obtained resin-coated metal sheet which was, then,
punched into a circular shape of a diameter of 154 mm and from
which a shallowly drawn cup was formed relying on an established
method. The thus drawn cup was subjected to the simultaneous
draw/ironing working two times repetitively to form a cup having a
small diameter and a large height. The thus obtained cup possessed
the following characteristics.
TABLE-US-00003 Cup diameter 66 mm Cup height 128 mm Thickness of
can wall relative to the -60% initial sheet thickness
[0254] After subjected to the doming, the cup was heat-treated at
220.degree. C. for 60 seconds to remove distortion from the resin
film, followed by trimming for the opening end, printing on the
curved surface, necking for forming a 206-diameter, flanging and
re-flanging to obtain a 350-g seamless can.
4. Evaluation of the Surface-Treated Metal Sheet
[0255] Part of the obtained surface-treated metal sheet was
measured for its weight film thicknesses, surface atomic ratios and
was evaluated for its adhesive property in the same manner as in
Example 1. The results were as shown in Table 5.
5. Evaluation of Retort Close Adhesion of the Metal Can
[0256] The inner surface of the can after re-flanging was scratched
over the whole circumference thereof so as to reach the metal blank
at a portion 5 mm lower than the opening end. The can in an empty
state was held in the hot steam of 125.degree. C. for 30 minutes to
observe the degree of exfoliation of the coated resin on the inner
surface of the can near the scratch and to evaluate the retort
close adhesion. The results were as shown in Table 5.
[0257] In Table 5, the retort close adhesion of the metal cans was
evaluated to be .circleincircle. when no can has developed
exfoliation among 20 cans, .largecircle. when no can has developed
exfoliation on the inner surface side among 20 cans but when not
more than two cans have partly developed exfoliation on the outer
surface side of the cans, and X when the cans have developed
exfoliation on the inner surface side of the cans or when not less
than three cans have developed exfoliation on the outer surface
side of the cans.
6. Evaluation of Corrosion Resistance of the Metal Cans
[0258] Metal cans packed with carbonated water such that the
pressure in the cans at 25.degree. C. was 3.5 kg/cm.sup.2 were
preserved at 37.degree. C. for one week and, thereafter, the can
temperature was lowered down to 5.degree. C. The metal cans in an
erected state were allowed to fall on a steel plate of a thickness
of ID mm tilted by 15.degree. with respect to the horizontal
direction from a height of 50 cm, so that the bottom radius
portions were deformed. Thereafter, the bottom portions of the cans
inclusive of the bottom radius portions were cut out in the
circumferential direction, and were immersed in a 0.1% sodium
chloride aqueous solution maintained at 50.degree. C. for 2 weeks.
Thereafter, the portions near the deformed bottom radius portions
were observed for their corrosion to evaluate the corrosion
resistance. The results were as shown in Table 5. In Table 5, the
deformed bottom radius portions were observed through a
stereomicroscope, and the corrosion resistance of the metal cans
was evaluated to be .largecircle. when no corrosion was observed
and X when the metal cans were corroded even to a small extent.
Example 13
[0259] The surface was treated, Coated with the resin, and the lids
were formed and evaluated in the same manner as in Example 12 but
using the treating bath B of Table 2 and setting the current
density to be 7 A/dm.sup.2.
Example 14
[0260] The surface was treated in the same manner as in Example 8
but using an aluminum alloy sheet, JIS 3004H19 having a thickness
of 0.26 mm. Thereafter, the surface was treated, coated with the
resin, and the lids were formed and evaluated in the same manner as
in Example 12.
Example 15
[0261] The metal sheet was treated for its surfaces in the same
manner as in Example 1, dipped in an aqueous solution containing 3%
of .gamma.-aminopropyltrimethoxysilane (product name: KBH903
produced by Shin-Etsu Kagaku Kogyo Co.), squeezed by the rolls, and
was dried at 120.degree. C. for one minute to obtain a
surface-treated metal sheet having a silane coupling agent layer
formed on the inorganic treating layer. In other respects, the
surface was treated and coated with the resin, and the lids were
formed and evaluated in the same manner as in Example 1. However,
the surface atomic ratios were those values obtained before the
organic treatment was effected,
Example 16
[0262] A surface-treating agent was prepared by removing the
hydrofluoric acid from the surface-treating agent comprising
chiefly the phenol-type water-soluble organic compound used in
Example 8, The metal sheet of which the surfaces were treated in
the same manner as in Example 1 was dipped in the surface-treating
agent, squeezed by the rolls, and was dried at 120.degree. C. for
one minute to obtain a surface-treated metal sheet having an
organic surface-treating layer comprising chiefly the phenol-type
water-soluble organic compound on the inorganic treating layer. In
other respects, the surface was treated and coated with the resin,
and the lids were formed and evaluated in the same manner as in
Example 1. However, the surface atomic ratios were those values
obtained before the organic treatment was effected.
Comparative Example 6
[0263] The surface was treated in the same manner as in Comparative
Example 0.1 taut using an aluminum alloy sheet, JIS 3004H19 having
a thickness of 0.26 mm as the metal sheet. Thereafter, the surface
was coated with the resin, and the lids were formed and evaluated
in the same manner as in Example 12.
Example 17
1. Formation of a Surface-Treated Metal Sheet
[0264] As a metal sheet, a cold-rolled steel sheet having a
thickness of 0.22 mm and a tempering degree of DR8 was pre-treated,
i.e., electrolytically dewaxed, washed with an acid, washed with
water, and washed with pure water. Next, the steel sheet was
treated in the same manner as in Example 1 but conducting the
cathodic electrolysis in the treating bath A of Table 2 at a
current density of 1 A/dm.sup.2, and flowing the current 0.6
seconds and halting the current 0.4 seconds repetitively 12 times.
Thereafter, the steel sheet was dipped in an aqueous solution
containing 3-1 of .gamma.-aminopropyltrimethoxysilane (product
name: KBM903 produced by Shin-Etsu Kagaku Kogyo Co.), squeezed by
the rolls, and was dried at 120.degree. C. for one minute to obtain
a surface-treated metal sheet having s silane coupling agent layer
of a thickness of 5 mg/m.sup.2 calculated as Si on the inorganic
treating layer.
2. Formation of a Resin-Coated Metal Sheet
[0265] The thus obtained surface-treated metal sheet was, first,
heated at 250.degree. C. The lower layer side of the cast film (b)
shown in Table 4 was thermally press-adhered onto one surface of
the metal sheet and the cast film (d) shown in Table 4 was
thermally press-adhered onto the another one surface that became
the outer surface Side by using the laminating rolls. The cast
films were immediately cooled with water to obtain a resin-coated
metal sheet.
3. Formation of Can Walls and Can Lids
[0266] A lubricating agent for working was applied onto the
obtained resin-coated metal sheet which was, then, re-drawn
(drawing ratio of 2.5) to form a can wall of an Inner diameter of
65.3 mm. Thereafter, the Can wall was heat-treated at 220.degree.
C. for 60 seconds to remove distortion from the resin film,
followed by trimming for the opening end and flanging to obtain a
deeply drawn can having a height of 101.1 mm. Further, part of the
thus obtained resin-coated metal sheet was formed into a full-open
lid of a 211-diameter relying on an established method.
4. Content Filling Test
[0267] To test the thus formed can wall and can lid, the can wall
was filled with a meat sauce, the full-open lid was double-seamed
therewith, and the retort sterilization treatment was conducted at
120.degree. C. for 30 minutes.
5. Evaluation of the Surface-Treated Metal Sheet
[0268] Part of the obtained surface-treated metal sheet was
measured for its weight film thicknesses and surface atomic ratios
in the same manner as in Example 1. The results were as shown in
Table 6,
6. Evaluation of the Containers
[0269] After the containers were formed, the organic coating was
examined if there were abnormal conditions such as exfoliation and
pitting. After preserved at 37.degree. C. for 6 months, the
containers containing the content were opened and examined for
corrosion or floating of organic coating on the inner surface side
of the containers. The results were as shown in Table 6,
Example 18
1. Formation of a Surface-Treated Metal Sheet
[0270] As a metal sheet, a cold-rolled steel sheet having a
thickness of 0.17 mm and a tempering degree of DR8 was pre-treated,
i.e., electrolytically dewaxed, washed with an acid, washed with
water, and washed with pure water and was, then, plated with nickel
in an amount of 0.3 g/m.sup.2 on each surface, plated with tin in
an amount of 0.6 g/m.sup.2 on each surface, and was reflow-treated
to form a nickel-tin-iron alloy layer on each surface. Next, the
steel sheet was cathodically electrolyzed in the treating bath A of
Table 2 and was treated with the silane coupling agent in the same
manner as in Example 17 to obtain a surface-treated metal
sheet.
2. Formation of a Resin-Coated Metal Sheet
[0271] The thus obtained surface-treated metal sheet was
roll-coated on both surfaces thereof with an epoxyacryl-type
aqueous coating material in a manner that the thickness of coating
after baked was 10 .mu.m followed by baking at 200.degree. C. for
10 minutes to obtain a resin-coated metal sheet.
3. Formation of can Walls and can Lids
[0272] A lubricating agent for working was applied onto the
obtained resin-coated metal sheet which was, then, re-drawn
(drawing ratio of 1.3) to form a can wall of an inner diameter of
83.3 mm. The can wall was, thereafter, subjected to the trimming
for the opening end and flanging to obtain a drawn can having a
height of 45.5 mm. Further, part of the thus obtained resin-coated
metal sheet was formed into a full-open lid of a 307-diameter
relying on an established method.
4. Content Filling Test
[0273] To test the thus formed can wall and can lid, the can wall
was filled with a tuna pickle in oil, the full-open lid was
double-seamed therewith, and the retort sterilization treatment was
conducted at 115.degree. C. for 60 minutes.
5. Evaluation of the Surface-Treated Metal Sheet
[0274] The surface-treated metal sheet was measured for its weight
film thicknesses and surface atomic ratios in the same manner as in
Example 17.
6. Evaluation of the Containers
[0275] The containers were evaluated in the same manner as in
Example 17 but further checking any discoloration due to
vulcanization after the containers were opened
Example 19
1. Formation of a Surface-Treated Metal Sheet
[0276] As a metal sheet, a cold-rolled steel sheet having a
thickness of 0.22 mm and a tempering degree of T4 was pre-treated,
i.e., electrolytically dewaxed, washed with an acid, washed with
water, washed with pure water and was, then, plated with tin in an
amount of 2.0 g/m.sup.2 on each surface, and was reflow-treated,
followed by the cathodic electrolysis in the treating bath A of
Table 2 by setting the current density to be 0.6 A/dm.sup.2 and
flowing the current for 0.6 seconds and halting the current for 0.4
seconds repetitively 8 times. In other respects, the cathodic
treatment was conducted in the same manner as in Example 1 to
obtain the surface-treated metal sheet for producing can walls.
[0277] Further, a cold-rolled steel sheet having a thickness of
0.21 mm and a tempering degree of T4 was also treated in the same
manner as described above to obtain a surface-treated metal sheet
for producing can lids.
2. Formation of a Resin-Coated Metal Sheet, Can Walls and Can
Lids
[0278] The surface-treated metal sheet for producing can walls was
marginally coated with the epoxyacrylic aqueous Coating material
excluding those portions corresponding to the seam portions of the
can wall in a manner that the film thicknesses after baking were 5
.mu.m on the inner surface side and 3 .mu.m on the outer surface
side, and was cured by baking in a hot air drying furnace heated at
200.degree. C. for 10 minutes to obtain a resin-coated metal sheet.
The resin-coated metal sheet was cut into a blank which was welded
into a cylindrical shape by using a commercially available
electric-resistance welding machine that uses a wire electrode.
Next, the inner and outer surfaces of the weld-seamed portions of
the can wall were spray-coated With a solvent-type epoxyurea
repairing material in a manner that the film thickness when dried
was 40 .mu.m, followed by baking in the hot air drying furnace
heated at 250.degree. C. for 3 minutes in order to obtain a welded
can wall (can diameter of 65.4 mm and a can wall height of 122 mm)
coating the seamed portions.
[0279] The surface-treated metal sheet for producing can lids, on
the other hand, was roll-coated on both surfaces thereof with an
epoxyacryl-type aqueous coating material in a manner that the
thickness of coating after baked was 10 .mu.m followed by baking at
200.degree. C. for 10 minutes to form a shell lid having a
209-diameter relying on an established method.
[0280] One open end of the can wall was subjected to the flanging
and the necking, and the above lid of the 209-diameter was
wrap-seamed therewith while the other open end thereof was
subjected to the triple necking and flanging.
3. Content Filling Test
[0281] The can wall was filled with a coffer at 50.degree. C., a
206-diameter aluminum SOT lid placed in the market was
double-seamed therewith, and the retort sterilization treatment was
conducted at 125.degree. C. for 25 minutes.
4. Evaluation of the Surface-Treated Metal Sheet
[0282] The surface-treated metal sheet was measured for its weight
film thicknesses and surface atomic ratios in the same manner as in
Example 17.
6. Evaluation of the Containers
[0283] The containers were evaluated in the same manner as in
Example 17 but further measuring the amount of iron elution after
the containers were opened.
Example 20
1. Formation of a Surface-Treated Metal Sheet
[0284] As a metal sheet, a cold-rolled steel sheet having a
thickness of 0.22 mm and a tempering degree of T4 was pre-treated,
i.e., electrolytically dewaxed, washed with an acid, washed with
water, washed with pure water and was, then, plated with nickel in
an amount of 0.03 g/m.sup.2 on each surface, plated with tin in an
amount of 1.3 g/m.sup.2 on each surface and was reflow-treated,
followed by the cathodic treatment in the treating bath A of Table
2 in the same manner as in Example 19 to obtain a surface-treated
metal sheet for producing can walls.
[0285] Further, a cold-rolled steel sheet having a thickness of
0.21 mm and a tempering degree of T4, too, was treated in the same
manner as described above to obtain a surface-treated metal sheet
for producing can lids.
2. Formation of a Resin-Coated Metal Sheet, Can Walls and Can
Lids
[0286] The surface-treated metal sheet for producing can walls was
marginally coated with an epoxyphenol solvent-type coating material
excluding those portions corresponding to the seam portions of the
can wall In a manner that the film thicknesses after baking were
0.5 .mu.m on the inner surface side and 3 .mu.m on the outer
surface side, and was cured by baking in a hot air drying furnace
heated at 200.degree. C. for 10 minutes to obtain a resin-coated
metal sheet. The resin-coated metal sheet was cut into a blank
which was welded into a cylindrical shape by using a commercially
available electric-resistance welding machine that uses a wire
electrode. Next, the inner and outer surfaces of the weld-seamed
portions of the can wall were spray-coated with a solvent-type
epoxyurea repairing material in a manner that the film thickness
when dried was 40 .mu.m, followed by baking in the hot air drying
furnace heated at 250.degree. C. for 3 minutes in order to obtain a
welded can wall (can diameter of 65.4 mm and a can wall height of
122 mm) coating the seamed portions.
[0287] The surf ace-treated metal sheet for producing can lids, on
the other hand, was roll-coated on both surfaces thereof with an
epoxyphenol-type solvent-type coating material in a manner that the
thickness of coating after baked was 10 .mu.m followed by baking at
200.degree. C. for 10 minutes to form a shell lid having a
209-diameter relying on an established method.
[0288] One open end of the can wall was subjected to the flanging
and the necking, and the above lid of 209-diameter was wrap-seamed
therewith while the other open end thereof was subjected to the
triple necking and flanging.
3. Content Filling Test
[0289] The can wall was hot-packed with ah orange juice at
93.degree. C., and a 206-diameter aluminum SOT lid placed in the
market was double-seamed therewith to seal.
4. Evaluation of the Surface-Treated Metal Sheet
[0290] The surface-treated metal sheet was measured for its weight
film thicknesses and surface atomic ratios in the same manner as in
Example 17,
5. Evaluation of the Containers
[0291] The containers were evaluated in the same manner as in
Example 19.
Example 21
1. Formation of a Surface-Treated Metal Sheet
[0292] As a metal sheet, a cold-rolled steel sheet having a
thickness of 0.195 mm and a tempering degree of T3 was pre-treated,
i.e., electrolytically dewaxed, washed with an acid, washed with
water, washed with pure water and was, then, plated with tin in an
amount of 1.0 g/m/z on each surface followed by the cathodic
treatment in the treating bath A of Table 2 in the same manner as
in Example 19 to obtain a surface-treated metal sheet fox producing
can walls.
[0293] Further, as a metal sheet, ah aluminum alloy sheet, JIS
5182H19 having a thickness of 0.285 mm was also cathodically
electrolyzed in the treating bath A of FIG. 2 by setting the
current density to be 5 A/dm.sup.2 and flowing the current for 0.6
seconds and holding the current for 0.4 seconds repetitively 8
times. In other respects, the treatment was conducted in the same
manner as in Example 1 to obtain a surface-treated metal sheet for
obtaining can lids.
2. Formation of a Resin-Coated Metal Sheet
[0294] The thus obtained surface-treated metal sheet for producing
can walls and can lids was, first, heated at 250.degree. C. The
lower layer side of the cast film (e) shown in Table 4 was
thermally press-adhered onto one surface of the metal sheet and the
east film (d) shown in Table 4 was thermally press-adhered onto the
another one surface that became the outer surface side using the
laminating rolls. The cast films were immediately cooled with water
to obtain a resin-coated metal sheet.
3. Formation of Metal Cans and Can Lids
[0295] A paraffin wax was electrostatically applied onto both
surfaces of the resin-coated metal sheet for producing can walls
which was, then, punched into a circular shape of a diameter of 140
mm and from which a shallowly drawn cup was formed relying on an
established method. The thus drawn cup was subjected to the
simultaneous draw/ironing working two times repetitively to form a
deeply drawn and ironed cup having a small diameter and a large
height. The thus obtained cup possessed the following
characteristics.
TABLE-US-00004 Cup diameter 5.2 mm Cup height 138 mm Thickness of
can wall relative to the -50% initial sheet thickness
[0296] After subjected to the doming, the cup was heat-treated at
220.degree. C. for 60 seconds to remove distortion from the resin
film, followed by trimming for the opening end, printing on the
curved surface, necking for forming a 200-diameter, flanging and
re-flanging to obtain a 250-g seamless can.
[0297] From the resin-coated metal sheet for producing can lids,
further, SOT lids of a 200-diameter were formed.
4. Content Filling Test
[0298] The above 250-g can wall was cold-packed with a coke at
5.degree. C., and the above SOT lid was double-seamed therewith to
seal.
5. Evaluation of the Surface-Treated Metal Sheet
[0299] The surface-treated metal sheet was measured for its weight
film thicknesses and surface atomic ratios in the same manner as in
Example 17.
6. Evaluation of the Containers
[0300] The containers were evaluated in the same manner as in
Example 19
Example 22
1. Formation of a Surface-Treated Metal Sheet and a Resin-Coated
Metal Sheet
[0301] An aluminum alloy sheet, JJS 3004H19, having a thickness of
0.28 mm was used as a metal sheet for producing can walls and an
aluminum alloy sheet, JIS 5182H19, having a thickness of 0.25 mm
was used as a metal sheet for producing can lids. These aluminum
alloy sheets were pre-treated, treated for their surfaces and were
coated with the resin in the same manner as in Example 2 with the
exception of being coated on their both surfaces with the cast film
(a) of Table 4.
[0302] A paraffin wax was electrostatically applied onto both
surfaces of the resin-coated metal sheet for producing can walls
which was, then, punched into a circular shape of a diameter of 166
mm and from which a shallowly drawn cup was formed relying on an
established method. The thus drawn cup was subjected to the
redraw/ironing working and to the deep-draw/ironing working to form
a can body. The thus obtained can body possessed the following
characteristics.
TABLE-US-00005 Can body diameter 66 mm Can body height 128 mm
Thickness of can wall relative to the -63% initial sheet
thickness
[0303] After subjected to the doming, the can body was heat-treated
at 220.degree. C. for 60 seconds to remove distortion from the
resin film, followed by trimming for the opening end, printing on
the curved surface, necking for forming a 206-diameter, flanging
and re-flanging to obtain a 350-g seamless can according to the
established method. From the resin-coated metal sheet for producing
can lids, further, SOT lids of a 206-diameter were formed according
to the established method.
2. Content Filling Test
[0304] The above 350-g can was cold-packed with a beer at 5.degree.
C., and the above SOT lid was double-seamed therewith to seal.
3. Evaluation of the Surface-Treated Metal Sheet
[0305] The surface-treated metal sheet was measured for its weight
film thicknesses and surface atomic ratios in the same manner as in
Example 17.
4. Evaluation of the Containers
[0306] The containers were evaluated in the same manner as in
Example 17 but further measuring the amount of aluminum elution
after the containers were opened. Table 2.
TABLE-US-00006 TABLE 2 Treating Ti Zr F bath mol/l mol/l mo/l A
0.025 -- 0.15 B 0.011 0.011 0.132 C 0.022 0.011 0.198 D 0.011 0.003
0.084 E 0.003 0.025 0.168 F 0.011 -- 0
TABLE-US-00007 TABLE 3 Polyester component Ratio of Titanium co-
Ionomer Tocopherol dioxide Copolymer polymer Content Content
Content Content component (mol %) (wt %) (wt %) (wt %) (wt %) A
isophthalic 12 100 -- -- -- acid B isophthalic 5 100 -- -- -- acid
C isophthalic 5 84 15 1 -- acid D isophthalic 12 75 -- -- 25 acid E
isophthalic 15 84 15 1 -- acid F isophthalic 15 100 -- -- --
acid
TABLE-US-00008 TABLE 4 Surface layer Lower layer Resin Thickness
Resin Thickness composition (.mu.m) composition (.mu.m) (a) A 12 --
-- (b) B 5 C 25 (c) C 30 -- -- (d) A 5 D 10 (e) B 5 E 25 (f) B 5 E
10 (g) B 5 F 10
TABLE-US-00009 TABLE 5 Evaluation of surface-treated metal sheets
Sur- face Weight film cov- Ad- thickness Surface atomic ering
hesive (mg/m.sup.2) ratio ratio prop- Ti Zr Si C O/M F/M P/M of Si
erty Ex. 1 23 -- -- -- 2.68 0.23 0.00 -- .largecircle. Ex. 2 65 --
-- -- 2.37 0.36 0.00 -- .largecircle. Ex. 3 15 54 -- -- 2.37 0.37
0.00 -- .circleincircle. Ex. 4 14 59 -- -- 2.72 0.44 0.00 --
.circleincircle. Ex. 5 36 49 -- -- 2.76 0.47 0.00 --
.circleincircle. Ex. 6 18 7 -- -- 2.65 0.35 0.00 --
.circleincircle. Ex. 7 42 -- 33 -- 2.63 0.60 0.00 20 .largecircle.
Ex. 8 43 10 -- 20 3.05 0.46 0.14 -- .circleincircle. Ex. 9 52 -- --
-- 3.80 0.72 0.20 -- .largecircle. Ex. 10 40 -- 38 -- 2.72 0.80
0.00 20 .circleincircle. Ex. 11 78 -- -- -- 3.90 0.70 0.00 --
.largecircle. Ex. 12 27 -- -- -- 2.75 0.27 0.00 -- .largecircle.
Ex. 13 17 48 -- -- 2.42 0.38 0.00 -- .largecircle. Ex. 14 51 8 --
20 3.12 0.49 0.12 -- .largecircle. Ex. 15 22 -- 5 -- 2.68 0.23 0.00
-- .circleincircle. Ex. 16 20 -- -- 15 2.68 0.23 0.00 --
.circleincircle. Comp. Ex. 1 14 -- -- -- 12.3 0.42 1.20 -- X Comp.
Ex. 2 342 -- -- -- 19.0 0.00 0.00 -- X Comp. Ex. 3 28 -- -- -- 125
18.5 0.00 -- X Comp. Ex. 4 38 -- -- -- 4.52 1.48 1.20 -- X Comp.
Ex. 5 25 -- 50 -- 2.68 0.23 0.00 -- X Comp. Ex. 6 17 -- -- -- 11.2
0.38 1.23 -- X Evaluation of containers Can Lid Close Corrosion
openability adhesion resistance Ex. 1 .largecircle. -- -- Ex. 2
.largecircle. -- -- Ex. 3 .circleincircle. -- -- Ex. 4
.circleincircle. -- -- Ex. 5 .circleincircle. -- -- Ex. 6
.circleincircle. -- -- Ex. 7 .largecircle. -- -- Ex. 8
.circleincircle. -- -- Ex. 9 .largecircle. -- -- Ex. 10
.circleincircle. -- -- Ex. 11 -- .largecircle. .largecircle. Ex. 12
-- .largecircle. .largecircle. Ex. 13 -- .largecircle.
.largecircle. Ex. 14 -- .largecircle. .largecircle. Ex. 15 --
.circleincircle. .largecircle. Ex. 16 -- .circleincircle.
.largecircle. Comp. Ex. 1 X -- -- Comp. Ex. 2 X -- -- Comp. Ex. 3 X
-- -- Comp. Ex. 4 X -- -- Comp. Ex. 5 X -- -- Comp. Ex. 6 -- X
X
TABLE-US-00010 TABLE 6 Evaluation of Evaluation of metal sheet
container property Ti wt. Surface Container Inner surface of
container film atomic formability State Color of Metal thickness
ratio State of State of of org. inner elution Use (mg/m.sup.2) O/Ti
F/Ti P/Ti org. film corrosion film surface (ppm) Ex. 17 can wall,
35 1.7 1.2 0 normal normal normal -- -- lid Ex. 18 can wall, 33 2.1
0.7 0 normal normal normal normal -- lid Ex. 19 wall 24 2.3 0.6 0
normal normal normal -- 0.00 lid 26 2.8 0.5 0 Ex. 20 wall 26 2.7
0.7 0 normal normal normal -- 0.12 lid 28 2.6 0.6 0 Ex. 21 wall 28
2.9 0.5 0 normal normal normal -- 0.03 lid 63 2.4 0.4 0 Ex. 22 wall
58 2.4 0.5 0 normal normal normal -- 0.00 lid 52 2.5 0.6 0
[Preparation of Treating Baths]
[0307] Treating baths were prepared by so adjusting the
concentrations of zirconium ions and fluorine ions as to obtain
aqueous solutions having the molar concentrations of Zr and F as
shown in Table 7, As the zirconium agent, however, a potassium
bromozirconate was used for the treating baths G and H, a zirconium
oxynitrate was used for the treating baths I and J, and an ammonium
fluorozirconate was used for the treating bath K. As the fluorine
agent, further, a sodium fluoride was used for part of the treating
bath H and for the whole of the treating baths I and J.
[Phenol-Type Aqueous Organic Compound]
[0308] The water-soluble polymer of the above formula (I) was used
as the phenol-type water-soluble organic compound.
[Formation of Polyester Films]
[0309] Polyester resins of compositions shown in Table 3 were
melt-extruded by using two extruders through a 2-layer T-die, were
cooled by the cooling rollers, and were taken up to obtain cast
films of constitutions shown in Table 4,
[0310] The surface-treated metal material was cut into a short
strip of a width of 5 mm and a length of 80 mm, and the cast film
(c) shown in Table 4 was cut into a short strip of a width of 5 mm
and a length of 80 mm. A cut piece of the above polyester film was
held between the two pieces of surface-treated short strips, which
was heated at 250.degree. C. for 3 seconds under a pressure of 2.0
kg/cm.sup.2 to obtain a T-peel test piece. Thereafter, a retort
treatment was conducted at 110.degree. C. for 60 minutes.
Immediately after the retort treatment, the test piece was immersed
in water, pulled out of water just prior to taking a measurement by
using a tension tester, and was measured for its adhering strength
at a tension speed of 10 mm/min.
Example 23
1. Formation of a Surface-Treated Metal Sheet
[0311] As a metal sheet, an aluminum alloy sheet, JIS 5021H18,
having a thickness of 0.25 mm was pretreated, i.e., treated with a
dewaxing agent 322N8 (produced by Nihon Paint Co.) according to an
established method in a bath maintained at 70.degree. C. for 10
seconds, and was washed with water, immersed in 1% sulfuric acid
maintained at 40.degree. C. for 5 seconds, washed with water and,
then, with pure water. Next, the cathodic electrolysis was
intermittently conducted in the treating bath G shown in Table 7
maintained at a bath temperature of 45.degree. C. with stirring,
using a titanium sheet coated with iridium oxide disposed at a
position maintaining an interelectrode distance of 17 mm as an
anode at a current density of 5 A/dm.sup.2 and flowing the current
for 0.4 seconds and halting the current for 0.6 seconds
repetitively 3 times. Immediately thereafter, the aluminum alloy
sheet was after-treated, i.e., washed with flowing water, then,
with pure water and was dried. Thereafter, the metal sheet was
dipped in an aqueous solution containing 3% of
.gamma.-aminopropyltrimethoxysilane (product name: KBM903 produced
by Shin-Etsu Kagaku Kogyo Co.), squeezed by the rolls, and was
dried at 120.degree. C. for one minute to obtain a surface-treated
metal sheet having a silane coupling agent layer formed on the
inorganic treating layer.
2. Formation of a Resin-Coated Metal Sheet
[0312] From the thus obtained surface-treated metal sheet, a
resin-coated metal sheet for producing lids was formed in a manner
as described below. First, the lower layer side of the cast film
(b) shown in Table 4 was thermally press-adhered onto one surface
of the surface-treated metal sheet that has been heated at a
temperature of 250.degree. C. by using the laminating rolls, and
was immediately cooled with water so as to form the coating on one
surface. Next, an epoxyacrylic coating material was applied to the
another one surface of the metal sheet that became the outer
surface side of the lid by roll-coating, and was baked at
185.degree. C. for 10 minutes.
3. Evaluation of the Surface-Treated Metal Sheet
[0313] Part of the obtained surface-treated metal sheet was
measured for its weight film thicknesses of Zr and the like, and
surface atomic ratios to the evaluate the adhesive property. The
results were as shown in Table 8.
[0314] In Table 8, the adhesive property was evaluated to be
.circleincircle. when a maximum tensile strength was not smaller
than 1.0 kg/5 mm, .largecircle. when the maximum tensile strength
was not smaller than 0.4 kg/5 mm but was smaller than 1.0 kg/5 mm,
and X when the maximum tensile strength was smaller than 0.4 kg/5
mm after the test pieces were exfoliated by more than 10 mm by
using the tension tester.
4. Evaluation of the Openability of Can Lids
[0315] From the obtained resin-coated metal sheet, full-open can
lids of a 301-diameter were formed according to an established
method, wrap-seamed with the can walls filled with water, put to
the retort sterilization treatment at 110.degree. C. for 60
minutes, cooled, and were immediately opened to observe the state
of exfoliation of resin in the opening portions around the score
portions to thereby evaluate the openability of the can lids. The
results were as shown in Table 8.
[0316] In Table 8, the openability of the can lids was examined by
observing the feathering around the opening portions, and was
evaluated to be .circleincircle. when the feathering was not
recognized at all, .largecircle. when the feathering was smaller
than 0.5 mm and the resin was not exfoliated, and X when the
feathering was not smaller than 0.5 mm.
Example 24
[0317] An inorganic coating was formed in the same manner as in
Example 23 but using a treating bath H of Table 7, setting the
current density to be 7 A/dm.sup.2, flowing the current for 0.6
seconds and halting the current for 0.4 seconds repetitively 4
times, and without conducting the treatment with the silane
coupling agent. Thereafter, the metal sheet was dipped in an
aqueous solution containing the solid component of the phenol-type
water-soluble polymer of the above formula (I) in an amount of 1
g/litter, squeezed by the roils and dried at 120.degree. C. for one
minute to obtain a surface-treated metal sheet having a phenol-type
organic surface-treating layer on the inorganic treating layer. The
surface-treated metal sheet was coated with the resin, and the lids
were formed and evaluated in the same manner as in Example 23.
Example 25
[0318] An aqueous solution containing:
TABLE-US-00011 Solid component of the phenol-type water-soluble 0.4
g/liter polymer of the above formula (I): Hydrofluoric acid (HF)
0.01 g/liter 75% Phosphoric acid (H.sub.3PO.sub.4) 0.20 g/liter 20%
Zirconium hydrogenfluoride (H.sub.2ZrF.sub.6) 1.3 g/liter
was prepared and used as the surface-treating agent.
[0319] The metal sheet was pretreated in the same manner as in
Example 23, was, thereafter, sprayed with the above
surface-treating agent at 40.degree. C. for 20 seconds, and was
washed with water and, then, with pure water. Thereafter, the metal
sheet was subjected to the inorganic surface treatment, coated with
the resin, and the lids were formed therefrom and evaluated in the
same manner as in Example 23 but without conducting the treatment
with the silane coupling agent.
Example 26
[0320] The metal sheet was treated with the silane coupling agent,
coated with the resin, and the lids were formed and evaluated in
the same manner as in Example 23 but conducting the inorganic
surface treatment by adding a potassium dihydrogenphosphate in an
amount of 0.001 mol/liter to the bath G of Table 7, setting the
current density to be 10 A/dm.sup.2 and flowing the current for 0.6
seconds and halting the current for 0.4 seconds repetitively 4
times.
Example 27
[0321] The metal sheet was treated with the silane coupling agent,
coated with the resin, and the lids were formed and evaluated in
the same manner as in Example 2.3 but using the treating bath J of
Table 7, setting the current density to be 10 A/dm.sup.2 and
flowing the current for 0.6 seconds and halting the current for 0.4
seconds repetitively 4 times.
Example 28
[0322] The metal sheet was subjected to the inorganic surface
treatment, to the treatment with the silane coupling agent, and was
coated with the resin, and the lids were formed and evaluated in
the same manner as in Example 23 but using a bath obtained by
adding the Snowtex C (produced by Nissan Kagaku Kogyo Co.) in an
amount of 60 g/liter to the bath G of Table 7.
Comparative Example 7
[0323] The metal sheet was subjected to the inorganic surface
treatment, was coated with the resin, and the lids were formed and
evaluated in the same manner as in Example 0.23 but conducting the
inorganic surface treatment at a current density of 2.5 A/dm.sup.2
and flowing the current for 0.6 seconds and halting the current for
0.4 seconds repetitively 5 times without conducting the treatment
with the silane coupling agent.
Comparative Example 8
[0324] The metal sheet was treated with the silane coupling agent,
coated with the resin, and the lids were formed and evaluated in
the same manner as in Example 23 but without conducting the
inorganic surface treatment after the metal sheet has been
pre-treated In the same manner as in Example 23.
Comparative Example 9
[0325] The metal sheet was coated with the resin, and the lids were
formed and evaluated in the same manner as in Example 25 by
pre-treating the metal sheet and treating the surfaces with the
phenol-type organic compound in the same manner as in Example 23
but without conducting the inorganic surface, treatment.
Comparative Example 10
[0326] The metal sheet was pretreated in the same manner as in
Example 23. Thereafter, a bath was prepared according to an
established method by using a commercially available zirconium-type
formation-treating solution (Alodine 404 manufactured by Ninon
Parkalizing Co.), and was sprayed thereon at a solution temperature
of 40.degree. C. for 15 seconds. Immediately thereafter, the metal
sheet was after-treated, i.e., washed with water and, then, with
pure water and was dried. Thereafter, the metal sheet was treated
with the salane coupling agent, coated with the resin, and the lids
were formed and evaluated in the same manner as in Example 23.
Comparative Example 11
[0327] The pretreatment and the inorganic surface treatment were
conducted in the same manner as in Comparative Example 10 but
spraying a commercially available zirconium-type formation-treating
solution (Alodine 404 manufactured by Ninon Parkalizing Co.) for 18
seconds. Thereafter, the metal sheet was subjected to the surface
treatment with the phenol-type organic compound, coated with the
resin, and the lids were formed and evaluated in the same manner as
in Example 24.
Comparative Example 12
[0328] The metal sheet was treated with the silane coupling agent,
coated with the resin, and the lids were formed and evaluated in
the same manner as in Example 23 but conducting the inorganic
surface treatment by using a treating bath I of Table 7 at a
current density of 10 A/dm.sup.2 and flowing the current for 0.6
seconds and halting the current for 0.4 seconds repetitively 4
times. However, the coating obtained by the inorganic surface
treatment was removed if it was washed with flowing water. After
the electrolysis, therefore, the surface-treated metal sheet was
Calmly immersed in a pool of water and was dried.
Comparative Example 13
[0329] The metal sheet was subjected to the inorganic surface
treatment, treated with the silane coupling agent, was coated with
the resin, and the lids were formed and evaluated in the same
manner as in Example 23 but conducting the cathodic electrolysis by
adding the potassium dihydrogenphosphate in an amount of 0.005
mols/liter to the bath G of Table 7, and flowing the current for
0.6 seconds and halting the current for 0.4 seconds repetitively 4
times.
Example 29
1. Formation of a Surface-Treated Metal Sheet and a Resin-Coated
Metal Sheet
[0330] An aluminum alloy sheet, JIS 3104H19, having a thickness of
0.28 mm was used as a metal sheet, and both surfaces thereof were
Coated with the lower layer sides of the cast films (g) and (f) of
Table 4. Thereafter, the metal sheet was subjected to the
pretreatment, inorganic surface treatment, treatment with the
silane coupling agent, and was coated with the resin in the same
manner as in Example 23.
[0331] A paraffin wax was electrostatically applied onto both
surfaces of the resin-coated metal sheet which was, then, punched
into a circular shape of a diameter of 166 mm and from which a
shallowly drawn cup was formed relying on an established method in
such a manner that the surface coated with the film (f) of Table 4
was on the inner surface side. Next, the shallowly drawn cup was
subjected to the redraw/ironing working to obtain a deeply drawn
and ironed can body. The thus obtained can body possessed the
following characteristics.
TABLE-US-00012 Can body diameter 66 mm Can body height 128 mm
Thickness of can wall relative to the -63% initial sheet
thickness
[0332] After subjected to the doming, the can body was heat-treated
at 220.degree. C. for 60 seconds to remove distortion from the
resin film, followed by trimming for the opening end, printing on
the curved surface, necking for forming a 206-diameter, flanging
and re-flanging to obtain a 350-g seamless can according to the
established method.
2. Evaluation of the Retort Close Adhesion of the Metal Can
[0333] The inner surface of the Can and the outer surface of the
can after re-flanging were scratched over the whole circumference
thereof so as to reach the metal blank at portions 5 mm lower than
the opening end. The can in an empty state was held in the hot
steam of 125.degree. C. for 30 minutes to observe the degree of
exfoliation of the coated resin on the inner and outer surfaces of
the can near the scratch and to evaluate the retort close adhesion.
The results were as shown in Table 8.
[0334] In Table 8, the retort close adhesion of the metal cans was
evaluated to be .circleincircle. when no can has developed
exfoliation among 20 cans, .largecircle. when no can has developed
exfoliation on the inner surface side among 20 cans but when not
more than two cans have partly developed exfoliation on the outer
surface side of the cans, and X when the cans have developed
exfoliation on the inner surface side of the cans or when not less
than three cans have developed exfoliation on the outer surface
side of the cans.
3. Evaluation of Corrosion Resistance of the Metal Cans
[0335] Metal cans packed with carbonated water such that the
pressure in the cans at 25.degree. C. was 3.5 kg/cm.sup.2 were
preserved at 37.degree. C. for one week and, thereafter, the can
temperature was lowered down to 5.degree. C. The metal cans in an
erected state were allowed to fall on a steel plate of a thickness
of 10 mm tilted by 15.degree. with respect to the horizontal
direction from a height of 50 cm, so that the bottom radius
portions were deformed. Thereafter, the bottom portions of the cans
inclusive of the bottom radius portions were cut out in the
circumferential direction, and were immersed in a 0.1% sodium
chloride aqueous solution maintained at 500 for 2 weeks.
Thereafter, the portions near the deformed bottom radius portions
were observed for their corrosion to evaluate the corrosion
resistance. The results were as shown in Table 8. In Table 8, the
deformed bottom radius portions were observed through a
stereomicroscope, and the corrosion resistance of the metal cans
was evaluated to be .largecircle. when no corrosion was observed
and X when the metal cans were corroded even to a small extent,
Example 30
[0336] A resin-coated metal sheet was prepared, the retort close
adhesion of the cans was evaluated and the corrosion resistance was
evaluated in the same manner as in Example 29 but conducting the
surface treatment in the same manner as in Example 24,
Example 31
[0337] A resin-coated metal sheet was prepared, the retort close
adhesion of the cans was evaluated and the corrosion resistance was
evaluated in the same manner as in Example 29 but conducting the
surface treatment in the same manner as in Example 25,
Example 32
[0338] A resin-coated metal sheet was prepared, the retort close
adhesion of the cans was evaluated and the corrosion resistance was
evaluated in the same manner as in Example 29 but conducting the
surface treatment in the same manner as in Example 28.
Example 33
[0339] A resin-coated metal sheet was formed, the retort close
adhesion of the cans was evaluated and the corrosion resistance was
evaluated in the same manner as in Example 0.29 tout conducting the
inorganic surface treatment by using a bath obtained by adding the
Snowtex C (produced by Nissan Kagaku Kogyo Co.) to the bath G of
Table 7, setting the current density to be 1 A/dm.sup.2, and
flowing the current for 0.6 seconds and halting the current for 0.4
seconds repetitively 3 times without conducting the organic
treatment.
Comparative Example 14
[0340] A resin-coated metal sheet was formed, the retort close
adhesion of the cans was evaluated and the corrosion resistance was
evaluated in the same manner as in Example 29 but conducting the
surface treatment in the same manner as in Comparative Example
7.
Comparative Example 15
[0341] A resin-coated metal sheet was formed, the retort close
adhesion of the cans was evaluated and the corrosion resistance was
evaluated in the same manner as in Example 29 but conducting the
surface treatment in the same manner as in Comparative Example
8.
Comparative Example 16
[0342] A resin-coated metal sheet was formed, the retort close
adhesion of the cans was evaluated and the corrosion resistance was
evaluated in the same manner as in Example 29 but conducting the
surface treatment in the same manner as in Comparative Example
9.
Example 34
1. Formation of a Surface-Treated Metal Sheet
[0343] As a metal sheet, a cold-rolled steel sheet having a
thickness of 0.195 mm and a tempering degree of T3 was pre-treated,
i.e., electrolytically dewaxed, washed with an acid, washed with
water, washed with pure water and was, then, plated with fin in an
amount of 1.0 g/m.sup.2 on each surface followed by the cathodic
treatment in the treating bath K of Table 7 at a current density of
0.6 A/dm.sup.2 flowing the current for 0.6 seconds and halting the
current for 0.4 seconds repetitively 8 times. In other respects,
the inorganic surface treatment was conducted followed by the
treatment with the silane coupling agent in the same manner as in
Example 23 to obtain a surface-treated metal sheet.
2. Formation of a Resin-Coated Metal Sheet
[0344] The thus obtained surf ace-treated metal sheet was, first,
heated at 250.degree. C. The lower layer side of the cast film (e)
shown in Table 4 was thermally press-adhered onto one surface of
the metal sheet and the cast film (d) shown in Table 4 was
thermally press-adhered onto the another one surface that became
the outer surface side using the laminating rolls. The cast films
were immediately cooled with water to obtain a resin-coated metal
sheet.
3. Formation of a Can Wall
[0345] A paraffin wax was electrostatically applied onto both
surfaces of the resin-coated metal sheet which was, then, punched
into a circular shape of a diameter of 140 mm and from which a
shallowly drawn Cup was formed relying on an established method.
The thus drawn cup was subjected to the redraw/ironing working two
times repetitively to form a deeply drawn and ironed cup having a
small diameter and a large height. The thus obtained cup possessed
the following characteristics.
TABLE-US-00013 Cup diameter 52 mm Cup height 138 mm Thickness of
can wall relative to the -50% initial sheet thickness
[0346] After subjected to the doming, the cup was heat-treated at
220.degree. C. for 60 seconds to remove distortion from the resin
film, followed by trimming for the opening end, printing on the
curved surface, necking for forming a 200-diameter, flanging and
re-flanging to obtain a 250-g seamless can.
4. Evaluation of the Surface-Treated Metal Sheet
[0347] The surface-treated metal sheet was measured for its weight
film thicknesses and surface atomic ratios in the same manner as in
Example 24,
5. Evaluation of the Close Adhesion at the Time of Forming
[0348] After the shallowly drawn cup was formed, the resin at the
end of the cup was observed for its follow-up state. The adhesion
was evaluated to be X when the resin was hanging down by more than
0.5 mm from the end of the cup, .DELTA. when the resin was hanging
down by not more than 0.5 mm but not less than 0.1 mm from the end
of the cup, and .largecircle. when the resin was hanging down by
less than 0-1 mm.
6. Evaluation of the Retort Close Adhesion
[0349] The outer surface of the can after re-flanging was scratched
over the whole circumference thereof so as to reach the metal blank
at a portion 5 mm lower than the opening end. The can in an empty
state was held in the hot steam of 125.degree. C. for 30 minutes to
observe the degree of exfoliation of the coated resin on the outer
surface of the can near the scratch and to evaluate the retort
close adhesion. The results were as shown in Table 9.
[0350] In Table 9, the retort close adhesion of the metal cans was
evaluated to be .largecircle. when there was no exfoliation at all,
.DELTA. when the coating was exfoliated partly, and X when the
coating was exfoliated over the whole circumference,
Example 35
[0351] The steel sheet was plated with tin in the same manner as in
Example 34, was subjected to the inorganic surface treatment by
using a bath obtained by adding the Snowtex C (produced by Nissan
Kagaku Kogyo Co.) in an amount of 60 g/liter to the bath K of Table
7 at a current density of 1 A/dm.sup.2 by flowing the current for
0.6 seconds and halting the current for 0.4 seconds repetitively 3
times, and was subjected to the treatment with the silane coupling
agent, coated with the resin, and the cans were formed and
evaluated in the same manner as in Example 0.34.
Example 36
[0352] The steel sheet same as that of Example 34 was plated with
tin, was subjected to the inorganic surface treatment by cathodic
electrolysis and was subjected to the surface treatment with the
phenol-type organic compound in the same manner as in Example 24 to
obtain a surface-treated metal sheet having an organic
surface-treating layer formed on the inorganic surface-treating
layer. Thereafter, the surface-treated metal sheet was coated with
the resin, and the cans were formed and evaluated in the same
manner as in Example 34.
Comparative Example 17
[0353] The steel sheet was subjected to the surface treatment,
coated with the resin, and the cans were formed and evaluated in
the same manner as in Example 34 but without conducting the
treatment with the silane coupling agent,
Comparative Example 18
[0354] After plated with tin, the steel sheet was subjected to the
surface treatment, coated with the resin, and the cans were formed
and evaluated in the same manner as in Example 34 but effecting
neither the inorganic surface treatment nor the treatment with the
silane coupling agent, i.e., coating the tin plating directly with
the resin.
Comparative Example 19
[0355] The steel sheet was plated with tin and was subjected to the
cathodic electrolysis in an aqueous solution containing sodium
dichromate in an amount of 30 g/liter to form an inorganic coating
of chromium oxide in an amount of 5 mg/m.sup.2 to thereby obtain a
surface-treated metal sheet which was, then coated with the resin,
and from which the cans were formed and evaluated in the same
manner as in Example 34.
Comparative Example 20
[0356] The steel sheet was plated with tin and was subjected to the
inorganic surface treatment in the same manner as in Example 34.
Thereafter, the metal sheet was dipped in an aqueous solution
containing 30% of .gamma.-aminopropyltrimethoxysilane (product
name: KBM903 produced by Shin-Etsu Kagaku Kogyo Co.), squeezed by
the rolls, and was dried at 120.degree. C. for one minute to obtain
a surface-treated metal sheet having a silane coupling agent layer
of a thickness of 50 mg/m.sup.2 calculated as Si on the inorganic
treating layer. Thereafter, the surface-treated metal sheet was
coated with the resin and from which the cans were formed and
evaluated in the same manner as in Example 34.
Comparative Example 21
[0357] The steel sheet was plated with tin and was subjected to the
inorganic surface treatment in the same manner as in Example 34,
Thereafter, the metal sheet was dipped in an aqueous solution
containing 0.5% of .gamma.-aminopropyltrimethoxysilane (product
name: KBM903 produced by Shin-Etsu Kagaku Kogyo Co.), squeezed by
the rolls, and was dried at 120.degree. C. for one minute to obtain
a surface-treated metal sheet having a silane coupling agent layer
of a thickness of 0.3 mg/m.sup.2 calculated as Si on the inorganic
treating layer. Thereafter, the surface-treated metal sheet was
coated with the resin and from which the cans were formed and
evaluated in the same manner as in Example 34.
Comparative Example 22
[0358] The steel sheet was plated with tin in the same manner as in
Example 34. Without conducting the inorganic surface treatment,
however, the steel sheet was subjected to the surface treatment
with the phenol-type organic compound in the same manner as in
Example 36 to obtain a surface-treated metal sheet. Thereafter, the
surf ace-treated metal sheet was coated with the resin and from
which the cans were formed and evaluated in the same manner as in
Example 34.
Example 37
1, Formation of a Surface-Treated Metal Sheet
[0359] As a metal sheet, a cold-rolled steel sheet having a
thickness of 0.17 mm and a tempering degree of DR8 was pre-treated,
i.e., electrolytically dewaxed, washed with an acid, washed with
water, washed with pure water and was, then, plated with nickel in
an amount of 0.3 g/m.sup.2 on each surface and with tin in an
amount of 0.6 g/m.sup.2 on each surface followed by the re-flow
treatment to form a nickel-tin-iron alloy layer on each surface.
Thereafter, the cathodic electrolysis was conducted in the treating
bath K of Table 7 followed by the treatment with the silane
coupling agent in the same manner as in Example 0.34 to obtain a
surface-treated metal sheet.
2, Formation of a Resin-Coated Metal Sheet
[0360] The thus obtained surface-treated metal sheet was
roll-coated on its both surfaces with an epoxyacrylic aqueous
coating material such that the film thickness after baking was 10
.mu.m, and was baked at 200.degree. C. for 10 minutes to obtain a
resin-coated metal sheet.
3. Formation of Can Walls and Can Lids
[0361] A lubricating agent for working was applied onto the
obtained resin-coated metal sheet which was, then, drawn (drawing
ratio of 1.3) to form a can wall of an inner diameter of 83.3 mm.
Next, the open end was trimmed, thereafter, the flanging was
effected to form a drawn can of a height of 4.5.5 mm. By using part
of the thus obtained resin-coated metal sheet, further, full-open
lids of a 307-diameter were formed according to the established
method.
4. Content Filling Test
[0362] To test the thus formed can wall and can lid, the can wall
was filled with a tuna pickle in oil, the full-open lid was
double-seamed therewith, and the retort sterilization treatment was
conducted at 115.degree. C. for 60 minutes.
5. Evaluation of the Vulcanization Resistance
[0363] After filled with the contents and retort-sterilized, the
containers were preserved at 37.degree. C. for 6 months, and were
opened to examine any discoloration by vulcanization on the inner
surface sides of the can wall and the can lid. The containers were
evaluated to be X when they had been discolored conspicuously, and
.largecircle. when they had not been greatly discolored. The
results were as shown in Table 9.
Comparative Example 23
[0364] The steel sheet was plated with nickel and with tin, and was
subjected to the reflow treatment to form a nickel-tin-iron alloy
layer in the same manner as in Example 37. The thus treated steel
sheet was, thereafter, treated with the silane coupling agent in
the same manner as in Example 37 without, however, conducting the
inorganic surface treatment to thereby obtain a surface-treated
metal sheet. Thereafter, the steel sheet was coated with the resin
and from which the can walls and can lids were formed and evaluated
in the same manner as in Example 37.
Example 38
1. Formation of a Surface-Treated Metal Sheet
[0365] As a metal sheet, a cold-rolled steel sheet having a
thickness of 0.22 mm and a tempering degree of T4 was pre-treated,
i.e., electrolytically dewaxed, washed with an acid, washed with
water, washed with pure water and was, then, plated with nickel in
an amount of 0.03 g/m.sup.2 on each surface, plated with tin in an
amount of 1.3 g/m.sup.2 on each surface and was ref low-treated,
followed by the Inorganic surface treatment and the treatment with
the silane coupling agent to obtain a surface-treated metal sheet
for producing can walls.
[0366] Further, a cold-rolled steel sheet having a thickness of
0.21 mm and a tempering degree of T4, too, was treated in the same
manner as described above to obtain a surf ace-treated metal sheet
for producing can lids.
2. Formation of a Resin-Coated Metal Sheet, Can Walls and Can
Lids
[0367] The surface-treated metal sheet for producing can walls was
marginally coated with an epoxyphenol solvent-type coating material
except those portions corresponding to the seam portions of the can
wall in a manner that the film thicknesses after baking were 5
.mu.m on the inner surface side and 3 .mu.m on the outer surface
side, and was cured by baking in a hot air drying furnace heated at
200.degree. C. for 10 minutes to obtain a resin-coated metal sheet.
The resin-coated metal sheet was cut into a blank which was welded
into a cylindrical shape by using a commercially available
electric-resistance Welding machine that uses a wire electrode.
Next, the inner and outer surfaces of the weld-seamed portions of
the can wall were spray-coated with a solvent-type epoxyurea
repairing material in a manner that the film thickness when dried
was 40 .mu.m, followed by baking in the hot air drying furnace
heated at 250.degree. C. for 3 minutes in order to obtain a welded
can wall (can diameter of 65.4 mm and a can wall height of 12.2 mm)
coating the seamed portions.
[0368] The surf ace-treated metal sheet for producing can lids, on
the other hand, was roll-coated on both surfaces thereof with an
epoxyphenol solvent-type coating material in a manner that the
thickness of coating after baked was 10 .mu.m followed by baking at
200.degree. C. for 10 minutes to form a shell lid having a
209-diameter relying on an established method.
[0369] One open end of the can wall was subjected to the flanging
and necking, and the above lid of the 209-diameter was wrap-seamed
therewith while the other open end thereof was subjected to the
triple necking and flanging.
3. Content Filling Test
[0370] The can wall was hot-packed with an orange juice at
93.degree. C., and a 206-diameter aluminum SOT lid placed in the
market was double-seamed therewith to seal.
4. Evaluation of the Corrosion Resistance
[0371] After filled with the contents, the containers were
preserved at 37.degree. C. for 6 months, and were opened to also
examine the amount of iron that has eluted out. The containers were
evaluated to be X when the amount of elution was not smaller than
0.2 ppm, .largecircle. when the amount of elution was not smaller
than 0.1 pp but was smaller than 0.2 ppm, and .circleincircle. when
the amount of elution was smaller than 0.1 ppm. The results were as
shown in Table 9.
Example 39
[0372] The steel sheet was plated with nickel and tin, and was
reflow-treated in the same manner as in Example 38. Thereafter, the
steel sheet was subjected to the inorganic surface treatment by
using a bath obtained by adding the Snowtex C (produced by Nissan
Kagaku Kogyo Co.) in an amount of 60-g/liter to the bath K of Table
7 at a current density of 5 A/dm.sup.2 by flowing the current for
0.6 seconds and halting the current for 0.4 seconds repetitively 3
times, and was subjected to the treatment with the silane coupling
agent, coated with the resin, and the cans and lids were formed and
evaluated in the same manner as in Example 38,
Comparative Example 24
[0373] The steel sheet was plated with nickel and tin, and was
reflow-treated in the same manner as in Example 38. Thereafter, the
steel sheet was subjected to the inorganic surface treatment by
using the bath K of Table 7, setting the current density to be 0.6
A/dm.sup.2 and flowing the current for 0.6 seconds and halting the
current for 0.4 seconds repetitively 8 times. Without conducting
the treatment with the silane coupling agent, however, the above
treated steel sheet was coated with the resin, and the cans and
lids were formed and evaluated in the same manner as in Example
38.
Example 40
1. Formation of a Surface-Treated Metal Sheet
[0374] As a metal sheet, a cold-rolled steel sheet having a
thickness of 0.22 mm and a tempering degree of DR8 was pre-treated,
i.e., electrolytically dewaxed, washed with an acid, washed with
water and washed with pure water. The thus treated steel sheet was
subjected to the inorganic surface treatment and to the treatment
with the silane coupling agent in the same manner as in Example 23
but conducting the cathodic electrolysis in the treating bath K of
Table 7 at a current density of 0.6 A/dm.sup.2 flowing the current
for 0.6 seconds and halting the current for 0.4 seconds
repetitively 8 times.
2. Formation of a Resin-Coated Metal Sheet
[0375] The thus obtained surface-treated metal sheet was, first,
heated at 250.degree. C. The lower layer side of the cast film (b)
shown in Table 4 was thermally press-adhered onto one surface of
the metal sheet and the cast film (d) shown in Table 4 was
thermally press-adhered onto the another one surface that became
the outer surface side using the laminating rolls. The cast films
were immediately cooled with water to obtain a resin-coated metal
sheet,
3. Formation of Can Walls and Can Lids
[0376] A lubricating agent for working was applied onto the
obtained resin-Coated metal sheet which was, then, redrawn (drawing
ratio of 2.5) to form a can wall of an inner diameter of 65.3 mm.
Next, the can wall was heat-treated at 22.013 for 60 seconds to
remove distortion from the resin film, followed by trimming for the
opening end and flanging to form a deeply drawn can having a height
of 10.1.1 mm. By using part of the thus obtained resin-coated metal
sheet, on the other hand, a full-open lid of a 211-diameter was
formed according to an established method.
4. Content Filling Test
[0377] To test the thus formed can wall and can lid, the can wall
was filled with a meat sauce, the full-open lid was double-seamed
therewith, and the retort sterilization treatment was conducted at
120.degree. C. for 30 minutes,
5. Evaluation of the Inner Surface State of the Containers
[0378] The containers that were formed were examined for their
state of organic coating to observe any abnormal condition such as
exfoliation and pitting. Further, after filled with the contents,
the containers were preserved stored at 37.degree. C. for 6 months,
and were opened to examine the corrosion and floating of the
organic coating on the inner surface side of the containers. The
results were as shown in Table 9.
TABLE-US-00014 TABLE 7 Treating Zr F bath mol/l mo/l G 0.022 0.132
H 0.011 0.090 I 0.100 0.400 J 0.020 0.050 K 0.022 0.132
TABLE-US-00015 TABLE 8 Evaluation of metal sheet Si sur- Wt. film
face thickness Surface cover- Ad- (mg/m.sup.2) atomic ratio ing
hesive Zr Si C O/Zr F/Zr P/Zr ratio property Ex. 23, 29 67 5 -- 2.4
0.4 0.0 -- .largecircle. Ex. 24, 30 42 -- 10 2.8 0.9 0.0 --
.largecircle. Ex. 25, 31 71 -- 12 3.1 0.5 0.2 -- .largecircle. Ex.
26 79 6 -- 2.8 1.1 0.2 -- .largecircle. Ex. 27 23 6 -- 3.8 0.7 0.0
-- .largecircle. Ex. 28, 32 74 30 -- 2.6 0.5 0.0 23
.circleincircle. Ex. 33 48 26 -- 5.5 1.0 0.0 25 -- Comp. ex. 7, 14
82 -- -- 2.6 1.3 0.0 -- .largecircle. Comp. ex. 8, 15 -- 5 -- -- --
-- -- X Comp. ex. 9, 16 5 -- 13 6.0 0.5 1.2 -- X Comp. Ex. 10 9 6
-- 9.1 0.5 1.1 -- X Comp. Ex. 11 13 -- 15 11 0.3 0.9 -- X Comp. Ex.
12 69 5 -- 593 22 0.0 -- X Comp. Ex. 13 70 5 -- 5.5 2.1 1.1 --
.largecircle. Evaluation of containers Can Lid Close Corrosion
openability adhesion resistance Ex. 23, 29 .circleincircle.
.circleincircle. .largecircle. Ex. 24, 30 .circleincircle.
.circleincircle. .largecircle. Ex. 25, 31 .circleincircle.
.circleincircle. .largecircle. Ex. 26 .circleincircle. -- -- Ex. 27
.circleincircle. -- -- Ex. 28, 32 .circleincircle. .circleincircle.
.largecircle. Ex. 33 -- .largecircle. .largecircle. Comp. ex. 7, 14
.largecircle. .largecircle. .largecircle. Comp. ex. 8, 15 X
.largecircle. X Comp. ex. 9, 16 X .largecircle. X Comp. Ex. 10 X --
-- Comp. Ex. 11 X -- -- Comp. Ex. 12 X -- -- Comp. Ex. 13
.largecircle. -- --
TABLE-US-00016 TABLE 9 Evaluation of metal sheet Wt. film thickness
Surface Si surface (mg/m.sup.2) atomic ratio covering Zr Si C O/Zr
F/Zr P/Zr ratio Ex. 34, 37, 38, 40 20 5 -- 3.7 0.4 0.0 -- Ex. 35,
39 33 52 -- 5.8 0.5 0.0 20 Ex. 36 24 -- 13 2.5 1.1 0.0 -- Comp. ex.
17, 24 54 -- -- 2.8 0.6 0.0 -- Comp. Ex. 18 -- -- -- -- -- -- --
Comp. Ex. 19 -- -- -- -- -- -- -- Comp. Ex. 20 29 50 -- 2.5 0.7 0.0
-- Comp. Ex. 21 20 0.3 -- 2.7 0.6 0.0 -- Comp. Ex. 22 -- -- 15 --
-- -- -- Comp. Ex. 23 -- 5 -- -- -- -- -- Evaluation of container
property Deep-draw/ironed can Deep-drawn can Close Close Welded
State of adhesion adhesion Drawn can can inner surface when when
Vulcanization Corrosion After After formed retorted resistance
resistance formed preserved Ex. 34, 37, 38, 40 .largecircle.
.largecircle. .largecircle. .largecircle. normal normal Ex. 35, 39
.largecircle. .largecircle. -- .circleincircle. -- -- Ex. 36
.largecircle. .largecircle. -- -- -- -- Comp. ex. 17, 24
.largecircle. .DELTA. -- .largecircle. -- -- Comp. Ex. 18 .DELTA. X
-- -- -- -- Comp. Ex. 19 .largecircle. .DELTA. -- -- -- -- Comp.
Ex. 20 .DELTA. .DELTA. -- -- -- -- Comp. Ex. 21 .largecircle.
.DELTA. -- -- -- -- Comp. Ex. 22 .DELTA. .DELTA. -- X -- -- Comp.
Ex. 23 .largecircle. -- X X -- --
[Preparation of the Treating Bath]
[0379] Treating baths were prepared by so adjusting the
concentrations of aluminum ions, titanium ions, zirconium ions and
fluorine ions that the aqueous solutions acquired molar
concentrations of Al, Ti, Zr and F as shown in Table 10. As the
aluminum agent, however, an aluminum nitrate
Al(NO.sub.3).sub.3.9H.sub.2O was used for the treating baths L, M,
N, O, P, Q, U, V, W, X, Y and Z, an aluminum sulfate
Al2(SO.sub.4).sub.3.13H2O was used for the treating bath R and an
aluminum dihydrogenphosphate solution Al(H2PO.sub.4).sub.3 was used
for the treating bath S. For the treating bath T, an agent was used
that was obtained by mixing the aluminum dihydrogenphosphate
solution Al(H2PO.sub.4).sub.3 and an aluminum dihydrogenphosphate
aluminum nitrate solution
Al(H2PO.sub.4).sub.3Al(NO.sub.3).sub.3.9H.sub.2O at a molar ratio
of 2 to 8. As the zirconium agent, an ammonium zirconium fluoride
(NH.sub.4).sub.2ZrF.sub.6 was used for the treating baths U and W.
As the titanium agent, an ammonium titanium fluoride
(NH.sub.4).sub.2TiF.sub.6 was used for the treating baths V and W.
As a fluorine source, further, a sodium fluoride NaF was used for
the treating baths M, O, Q, T and X, an ammonium fluoride NH.sub.4F
was used for the treating baths P and Z, and a boric acid
H.sub.3BO.sub.3 was used as a buffer agent for the treating baths M
and O.
[Formation of the Polyester Films]
[0380] Polyester resins of compositions shown in Table 11 were
melt-extruded from the two extruders through a two-layer T-die, and
were cooled by the cooling rolls. The thus obtained films were
taken up to obtain cast films (h), (i), (j), (k), (l), (m) and (n)
constituted as shown in Table 12.
<Evaluation of the Steel Members>
[Evaluation of the Adhesive Property]
[0381] The surface-treated metal material was cut into a short
strip of a width of 5 mm and a length of 80 mm, and the cast film
(n) shown in Table 12 was cut into a short strip of a width of 5 mm
and a length of 80 mm. A cut piece of the above polyester film was
held between the two pieces of surface-treated short strips, which
was heated at 220.degree. C. for 3 seconds under a pressure of 2.0
kg/cm.sup.2 to obtain a T-peel test piece. Thereafter, a retort
treatment was conducted at 110.degree. C. for 60 minutes.
Immediately after the retort treatment, the test piece was immersed
in water, pulled out of water just prior to taking a measurement by
using a tension tester, and was measured for its adhering strength
at a tension speed of 10 mm/min.
[Evaluation of the Corrosion Resistance]
[0382] The surface-treated metal material was cut into a short
strip of a width of 70 mm and a length of 150 mm, and the cut
portions were protected over a width of 3 mm with a tape. The
surface-treated metal material was sprayed with a 5% NaCl aqueous
solution maintained at 35.degree. C. for 6 hours to observe the
occurrence of iron rust.
[Evaluation of the Vulcanization Resistance]
[0383] The surface-treated metal material was cut into a square of
70 mm and was protruded by using the Erichsen tester. Next, the cut
portions were protected over a width of 3 mm with a tape, and the
surface-treated metal material was immersed in a model solution of
a mixture of 4.5 g/liter of a potassium dihydrogenphosphate
KH.sub.2PO.sub.4, 12 g/liter of a sodium hydrogenphosphate
Na.sub.2HPO.sub.4.12H.sub.2O and a 2 g/liter of an L-cystine
hydrochlorate monohydrate, and was retort-treated in a sealed
container at 115.degree. C. for 60 minutes.
[Evaluation of Discoloration]
[0384] The surface-treated metal material was cut into a square of
70 mm, heated at 200.degree. C. for one hour to compare the degree
of discoloration after having been heated.
Example 41
1. Formation of a Surface-Treated Metal Sheet
[0385] As a metal sheet, a cold-rolled steel sheet having a
thickness of 0.195 mm and a tempering degree of T3 was pre-treated,
i.e., eleetrolytically dewaxed, washed with an acid, washed with
water, washed with pure water and was, then, plated with tin in an
amount of 1.3 g/m.sup.2 on each surface, reflow-treated and was,
then, subjected to the cathodic electrolysis in the treating bath L
of Table 10 at a bath temperature of 45.degree. C. with stirring
using, as an anode, a titanium sheet coated with iridium oxide
disposed at a position of an interelectrode distance of 17 mm at a
current density of 2 A/dm.sup.2 for 12 seconds immediately followed
by the after-treatment, i.e., washing with flowing water, washing
with pure water and drying.
2. Evaluation of the Surface-Treated Metal Material
[0386] Part of the obtained surface-treated metal material was
measured for its weight film thicknesses such as of Al, Ti and Zr,
surface atomic ratios, surface exposure ratios, and was evaluated
for its corrosion resistance and adhesive property. The results
were as shown in Table 13.
[0387] In Table 13, the adhesive property was evaluated to be
.circleincircle. when a maximum tensile strength was not smaller
than 0.6 kg/5 mm, .largecircle. when the maximum tensile strength
was not smaller than 0.3 kg/5 mm but was smaller than 0.6 kg/5 mm,
.DELTA. when the maximum tensile strength was not smaller than 0.2
kg/5 mm but was smaller than 0.3 kg/5 mm and X when the maximum
tensile strength was smaller than 0.2 kg/5 mm after the test pieces
were exfoliated by more than 10 mm by using the tension tester.
[0388] Further, the corrosion resistance was evaluated to be
.circleincircle. when almost no rust was developing, .largecircle.
when rust was slightly recognized, .DELTA. when rust was developing
not less than 10% but less than 0.20% of the surface areas, and X
when rust was developing not less than 20% of the surface
areas.
[0389] Further, the vulcanization resistance was evaluated to be
.circleincircle. when the worked portions had not been discolored,
.largecircle. when the worked portions had been discolored not more
than 25% as the area ratio, and X when the worked portions had been
further discolored.
[0390] The discoloration was evaluated by eyes to be .largecircle.
when there was almost no discoloration or when the discolored
portions occupied less than 20% as the area ratio, and X when the
discolored portions occupied more than 20% as the area ratio.
Example 42
[0391] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
plating tin in an amount of 5.6 g/m.sup.2 and Intermittently
conducting the cathodic electrolysis in the treating bath M of
Table 10 at a current density of 2 A/dm.sup.2 and flowing the
current for 0.6 seconds and halting the current for 0.4 seconds
repetitively 8 times.
Example 43
[0392] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
conducting the cathodic electrolysis in the treating bath N in
Table 10 at a current density of 1 A/dm.sup.2 for 24 seconds.
Example 44
[0393] The inorganic surface-treating layer was formed in the same
manner as in Example 43 but plating tin in an amount of 0.4
g/m.sup.2, and forming an alloy layer by reflowing, so that there
was no free tin on the surfaces, and the surface-treated metal
material was evaluated in the same manner as in Example 40.
Example 45
[0394] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
conducting the cathodic electrolysis in the treating bath M in
Table 10 at a current density of 1 A/dm.sup.2 for 12 seconds.
Example 46
[0395] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
plating tin in an amount of 0.4 g/m.sup.2, forming an alloy layer
by reflowing, so that there was no free tin on the surfaces, and
conducting the cathodic electrolysis in the treating bath M of
Table 10 at a current density of 1 A/dm.sup.2 for 4 seconds.
Example 47
[0396] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
plating tin in an amount of 2.8 g/m.sup.2 and intermittently
conducting the cathodic electrolysis in the treating bath M of
Table 1.0 at a current density of 1.2 A/dm.sup.2 and flowing the
current for 0.6 seconds and halting the current for 0.4 seconds
repetitively 16 times.
Example 48
[0397] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
plating tin in the same amount as that of Example 41 without
conducting the reflow treatment, and conducting the cathodic
electrolysis in the treating bath .largecircle. of Table 10 at a
current density of 1 A/dm.sup.2 for 4 seconds.
Example 49
[0398] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
plating tin in an amount of 0.9 g/m.sup.2 and intermittently
conducting the cathodic electrolysis in the treating bath P of
Table 10 at a current density of 1 A/dm.sup.2 and flowing the
current for 0.6 seconds and halting the current for 0.4 seconds
repetitively 6 times.
Example 50
[0399] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
conducting the cathodic electrolysis in the treating bath Q of
Table 10 at a current density of 1 A/dm.sup.2 for 8 seconds.
Example 51
[0400] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
intermittently conducting the cathodic electrolysis in the treating
bath R of Table 10 at a current density of 2 A/dm.sup.2 and flowing
the current for 0.6 seconds and halting the current for 0.4 seconds
repetitively 8 times.
Example 52
[0401] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
conducting the cathodic electrolysis in the treating bath S of
Table 10 at a current density of 2 A/dm.sup.2 for 24 seconds.
Example 53
[0402] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
conducting the cathodic electrolysis in the treating bath T of
Table 10 at a current density of 1 A/dm.sup.2 for 8 seconds.
Example 54
[0403] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
plating tin in an amount of 0.7 g/m.sup.2 and intermittently
conducting the cathodic electrolysis in the treating bath U of
Table 10 at a current density of 1 A/dm.sup.2 and flowing the
current for 0.6 seconds and halting the current for 0.4 seconds
repetitively 8 times.
Example 55
[0404] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
plating tin in an amount of 2.8 mg/m.sup.2 without conducting the
reflow treatment, and conducting the cathodic electrolysis in the
treating bath V of Table 10 at a current density of 2 A/dm.sup.2
for 8 seconds.
Example 56
[0405] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
intermittently conducting the cathodic electrolysis in the treating
bath W of Table 10 at a current density of 2 A/dm.sup.2 flowing the
current for 0.6 seconds and halting the current for 0.4 seconds
repetitively 16 times.
Example 57
[0406] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
conducting the cathodic electrolysis in the treating bath X in
Table 10 at a current density of 2 A/dm.sup.2 for 8 seconds.
Example 58
[0407] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
plating tin in an amount of 11.2 g/m.sup.2 and intermittently
conducting the cathodic electrolysis in the treating bath P of
Table 10 at a current density of 1 A/dm.sup.2 flowing the current
for 0.6 seconds and halting the current for 0.4 seconds
repetitively 4 times.
Comparative Example 25
[0408] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
conducting the cathodic electrolysis in the treating bath Q in
Table 0.10 at a current density of 1 A/dm.sup.2 for 16 seconds.
Comparative Example 26
[0409] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
plating tin in an amount of 0.4 g/m.sup.2, forming an alloy layer
by reflowing, so that there was no free tin on the surfaces, and
intermittently conducting the cathodic electrolysis in the treating
bath S of Table 0.10 at a current density of 0.2 A/dm.sup.2 flowing
the current for 0.6 seconds and halting the current for 0.4 seconds
repetitively 4 times.
Comparative Example 27
[0410] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
conducting the cathodic electrolysis in the treating bath S in
Table 10 at a current density of 2 A/dm.sup.2 for 4 seconds.
Comparative Example 28
[0411] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
plating tin in an amount of 0.4 g/m.sup.2, forming an alloy layer
by reflowing, so that there was no free tin on the surfaces, and
intermittently conducting the cathodic electrolysis in the treating
bath 2 of Table 10 at a current density of 2 A/dm.sup.2 flowing the
current for 0.6 seconds and halting the current for 0.4 seconds
repetitively 4 times.
Comparative Example 29
[0412] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
plating tin in an amount of 2.8 g/m.sup.2, conducting the cathodic
treatment in an aqueous solution of sodium dichromate, and
conducting the chrome-type surface treatment using chromium oxide
in an amount of 3 mg/m.sup.2 relying on an established method.
Comparative Example 30
[0413] The evaluation was conducted in the same manner as in
Example 41 but using a surface-treated metal material obtained by
conducting the Cathodic treatment in an aqueous solution of
anhydrous chromic acid and sulfuric acid, and conducting the
chrome-type surface treatment using metal chromium in an amount of
7 mg/m.sup.2 and chromium oxide in an amount of 12 mg/m.sup.2
relying on an established method.
Comparative Example 31
[0414] A surface-treated metal material was Obtained by conducting
the plating with tin and ref low treatment in the same manner as in
Example 41, and intermittently conducting the cathodic electrolysis
in an aqueous solution Containing 0.025 mols/liter of ammonium
fluorozirconate and 6.005 mols/liter of potassium nitrate at a
current density of 7.5 A/dm.sup.2 flowing the current for 0.6
seconds and halting the current for 0.4 seconds repetitively 4
times. Discoloration occurred conspicuously with the passage of
time, and no other properties were evaluated except
discoloration.
Example 59
1. Preparation of a Surface-Treating Agent Comprising Chiefly a
Phenol-Type Water-Soluble Organic Compound
[0415] A compound of the formula (I) above was used as the
phenol-type water-soluble organic compound.
2, Formation of a Surface-Treated Metal Material and its
Evaluation
[0416] The surface-treating agent comprising chiefly the
phenol-type water-soluble organic compound prepared in 1. above was
sprayed at 40.degree. C. for 20 seconds onto the inorganic
surface-treating layer formed in Example 41, and was washed with
water and, then, with pure water to obtain a surface-treated metal
material having an organic surf ace-treating layer formed on the
inorganic surface-treating layer. The adhesive property, corrosion
resistance and vulcanization resistance were evaluated in the same
manner as in Example 41 to obtain results as shown in Table 14.
Example 60
[0417] The treatment and evaluation were conducted in the same
manner as in Example 0.59 but forming a phenol-type water-soluble
organic compound layer on the inorganic surface-treating layer
formed in Example 42. Further, the surfaces were analyzed by XPS
before and after the organic surface treatment. A peak N1s was
confirmed that was not existing before the organic surface
treatment.
Example 61
[0418] The treatment and evaluation were conducted in the same
manner as in Example 59 but forming the phenol-type water-soluble
organic compound layer on the inorganic surface-treating layer
formed in Example 43,
Example 62
[0419] The inorganic surface-treating layer formed in Example 41
was dipped in an aqueous solution of 3% of
.gamma.-aminopropyltrimethoxysilane (product name, KBM903, produced
by Shin-Etsu Kagaku Kogyo Co.), squeezed by the rolls, and was
dried at 120.degree. C. for one minute to obtain a surface-treated
metal material having a silane coupling agent layer of a film
thickness calculated as Si of 5 mg/m.sup.2 formed on the
inorganic-treating layer. The surface-treated metal material was
evaluated in the same manner as in Example 59,
Example 63
[0420] The treatment and evaluation were conducted in the same
manner as in Example 62 but forming a silane coupling agent layer
on the inorganic surface-treating layer formed in Example 42.
Further, the surfaces were analyzed by XPS before and after the
organic surface treatment. A peak N1s was confirmed that was not
existing before the organic surface treatment.
Example 64
[0421] The treatment and evaluation were conducted in the same
manner as in Example 62 but forming a silane coupling agent layer
on the inorganic surface-treating layer formed in Example 46.
Example 65
[0422] The treatment and evaluation were conducted in the same
manner as in Example 62 but forming a silane coupling agent layer
on the inorganic surface-treating layer formed in Example 51.
Further, the surfaces were analyzed by XPS before and after the
organic surface treatment. A peak N1s was confirmed that was not
existing before the organic surface treatment.
Example 66
[0423] The treatment and evaluation were conducted in the same
manner as in Example 62 but forming a silane coupling agent layer
on the inorganic surface-treating layer formed in Example 51.
Example 67
[0424] The treatment and evaluation were conducted in the same
manner as in Example 62 but forming a silane coupling agent layer
on the inorganic surface-treating layer formed in Comparative
Example 25.
Example 68
[0425] The treatment and evaluation were conducted in the same
manner as in Example 62 but forming a silane coupling agent layer
on the inorganic surface-treating layer formed in Comparative
Example 26.
Example 69
[0426] The treatment and evaluation were conducted in the same
manner as in Example 62 but forming a silane coupling agent layer
on the inorganic surface-treating layer formed in Comparative
Example 0.27.
Example 70
[0427] The treatment and evaluation were conducted in the same
manner as in Example 62 but forming a silane coupling agent layer
on the inorganic surface-treating layer formed in Comparative
Example 28.
Comparative Example 32
[0428] The Inorganic surface-treating layer formed in Example 41
was dipped in an aqueous solution of 30% of
.gamma.-aminopropyltrimethoxysilane (product name, KBM903, produced
by Shin-etsu Kagaku Kogyo Co.), squeezed by the rolls, and was
dried at 120.degree. C. for one minute to obtain a surface-treated
metal material having a silane coupling agent layer of a film
thickness calculated as Si of 50 mg/m.sup.2 formed on the
inorganic-treating layer. The surf ace-treated metal material was
evaluated in the same manner as in Example 59.
Evaluation of Aluminum Material
Example 71
[0429] 1, Formation of a surface-treated metal material.
[0430] As a metal sheet, an aluminum alloy sheet, JIS 5021H18,
having a thickness of 0.25 mm was pretreated, i.e., treated with a
dewaxing agent 322N8 (produced by Ninon Paint Co.) in a bath
maintained at 70.degree. C. for 10 seconds, and was washed with
water, immersed in 1% sulfuric acid maintained at 40.degree. C. for
5 seconds, washed with water and, then, with pure water according
to an established method. Next, in the treating bath Q shown in
Table 10, the aluminum alloy sheet was subjected to the
intermittent cathodic electrolysis at a current density of 7
A/dm.sup.2 flowing the current for 0.4 seconds and halting the
current for 0.6 seconds repetitively 4 times to thereby obtain a
surface-treated aluminum sheet.
2. Formation of a Resin-Coated Metal Material
[0431] From the thus obtained surface-treated metal material, a
resin-coated metal material for producing lids was formed in a
manner as described below. First, the lower layer side of the cast
film (h) shown in Table 12 was thermally press-adhered onto one
surface of the surface-treated metal material that has been heated
at a temperature of 250.degree. C. by using the laminating rolls,
and was immediately cooled with water so as to form the coating on
one surface. Next, an epoxyacrylic coating material was applied to
the another one surface of the metal sheet that became the outer
surface side of the lid by roll-coating, and was baked at
185.degree. C. for 10 minutes.
3. Evaluation of the Surface-Treated Metal Material
[0432] Part of the obtained inorganic surface-treated metal
material was measured for its weight film thicknesses, surface
atomic ratios and was evaluated for its adhesive property. The
results were as shown in Table 15,
[0433] The film (i) of Table 12 was press-adhered to the adhesion
test pieces at 250.degree. C. to obtain T-peel test pieces in the
same manner as in Example 41. The adhesive property was evaluated
to be .circleincircle. when a maximum tensile strength was not
smaller than 0.6 kg/5 mm, .largecircle. when the maximum tensile
strength was not smaller than 0.3 kg/5 mm but was smaller than 0.6
kg/5 mm, and X when the maximum tensile strength was smaller than
0.3 kg/5 mm after the test pieces were exfoliated by more than 10
mm by using the tension tester.
4. Evaluation of the Openability of Can Lids
[0434] From the obtained resin-coated metal material, full-open can
lids of a 301-diameter were formed according to an established
method, wrap-seamed with the can walls filled with water, put to
the retort sterilization treatment at 110.degree. C. for 60
minutes, cooled, and were immediately opened to observe the state
of exfoliation of resin in the opening portions around the score
portions to thereby evaluate the openability of the can lids. The
results were as shown in Table 15.
[0435] In Table 15, the openability of the can lids was examined by
observing the feathering around the opening portions, and was
evaluated to be .circleincircle. when the feathering was not
recognized at all, .largecircle. when the feathering was smaller
than 0.5 mm and the resin was not exfoliated, and X when the
feathering was not smaller than 0.5 mm.
Example 72
1. Formation of a Surface-Treated Metal Material
[0436] The surface was treated in the same manner as in Example 71
but using, as a metal sheet, an aluminum alloy sheet, JIS 3004H19,
having a thickness of 0.26 mm.
2. Formation of a Resin-Coated Metal Material
[0437] The thus obtained surface-treated metal material was heated
at 250.degree. C., the lower layer side of the cast film (h) shown
in Table 12 was thermally press-adhered onto one surface of the
metal sheet, the cast film (m) of Table 12 was thermally
press-adhered onto another one surface thereof that became the
outer surface side of the can by using the laminating rolls, and
the films were immediately cooled with water to obtain a
resin-coated metal material.
3. Formation of the Metal Cans
[0438] A paraffin wax was electrostatically applied onto both
surfaces of the resin-coated metal material which was, then,
punched into a circular shape of a diameter of 154 mm and from
which a shallowly drawn cup was formed relying on an established
method. The thus drawn, cup was subjected to the simultaneous
draw/ironing working two times repetitively to form a cup having a
small diameter and a large height. The thus obtained cup possessed
the following characteristics.
TABLE-US-00017 Cup diameter 66 mm Cup height 128 mm Thickness of
can wall relative to the -60% initial sheet thickness
[0439] After subjected to the doming, the cup was heat-treated at
220.degree. C. for 60 seconds to remove distortion from the resin
film, followed by trimming for the opening end, printing on the
curved surface, necking for forming a 206-diameter, flanging and
re-flanging to obtain a 350-g seamless can.
4. Evaluation of the Surface-Treated Metal Material
[0440] The thus obtained inorganic surface-treated metal sheet was
measured for its weight film thicknesses and surface atomic ratios
in the same manner as in Example 41 to obtain the results as shown
in Table 1.5.
5. Evaluation of the Retort Close Adhesion of the Metal Cans
[0441] The outer surface of the can after re-flanging was scratched
over the whole circumference thereof so as to reach the metal blank
at a portion 5 mm lower than the opening end. The can in an empty
state was held in the hot steam of for 30 minutes to observe the
degree of exfoliation of the coated resin on the inner surface side
of the can near the scratch and to evaluate the retort close
adhesion. The results were as shown in Table 15.
[0442] In Table 15, the retort close adhesion of the metal cans was
evaluated to be .largecircle. when quite no can developed
exfoliation even partly among 20 cans, and X when there was a can
that developed exfoliation even partly among 20 cans.
6. Evaluation of Corrosion Resistance of the Metal Cans
[0443] Metal cans packed with carbonated water such that the
pressure in the cans at 25.degree. C. was 3.5 kg/cm.sup.2 were
preserved at 37.degree. C. for one week and, thereafter, the can
temperature was lowered down to 5.degree. C. The metal cans in an
erected state were allowed to fall on a steel plate of a thickness
of 10 mm tilted by 15.degree. with respect to the horizontal
direction from a height of 50 cm, so that the bottom radius
portions were deformed. Thereafter, the bottom portions of the cans
inclusive of the bottom radius portions were cut out in the
circumferential direction, and were immersed in a 0.1% sodium
chloride aqueous solution maintained at 50.degree. C. for 2 weeks.
Thereafter, the portions near the deformed bottom radius portions
were observed for their corrosion to evaluate the corrosion
resistance. The results were as shown in Table 15.
[0444] In Table 15, the deformed bottom radius portions were
observed through a stereomicroscope, and the corrosion resistance
of the metal cans was evaluated to be .largecircle. when no
corrosion was observed and X when the metal cans were corroded even
to a small extent,
Example 73
[0445] The surface-treated metal material was coated with the
resin, and from which the lids were formed and evaluated in the
same manner as in Example 71 but treating the metal sheet and
forming the inorganic surface-treating layer thereon in the same
manner as in Example 71, and forming a silane coupling agent layer
having a thickness calculated as Si of 5 mg/m.sup.2 on the
inorganic-treating layer in the same manner as in Example 62
Example 74
[0446] The surface-treated metal material was coated with the
resin, and from which the lids were formed and evaluated in the
same manner as in Example 72 but treating the metal sheet and
forming the inorganic surface-treating layer thereon in the same
manner as in Example 72, and forming a silane coupling agent layer
having a thickness calculated as Si of 5 mg/m.sup.2 on the
inorganic-treating layer in the same manner as in Example 62.
Comparative Example 33
[0447] The aluminum alloy sheet, JIS 5021H18, having a thickness of
0.25 mm was pre-treated in the same manner as in Example 71 but was
not subjected to the inorganic surface treatment. The metal sheet
was, thereafter, subjected to the phenol-type organic surface
treatment in the same manner as in Example 59 and was, thereafter,
coated with the resin and from which the lids were formed and
evaluated in the same manner as in Example 71. The weight film
thickness formed by the organic surface treatment was 13 mg/m.sup.2
as calculated as the amount of C and was 5 mg/m.sup.2 as calculated
as the amount of Zr,
Comparative Example 34
[0448] The aluminum alloy sheet, JIS 5021H18, having a thickness of
0.25 mm was pre-treated in the same manner as in Example 71. A bath
was prepared according to an established method by using a
commercially available zirconium-type formation-treating solution
(Alodine 404, produced by Nihon Parkalizing Co.), was sprayed
thereon at a solution temperature of 40.degree. C. for 15 seconds,
and was, immediately thereafter, subjected to the after-treated,
i.e., washed with water, washed with pure water and was dried.
Thereafter, the surface-treated metal sheet was coated with the
resin, and from which the lids were formed and evaluated in the
same manner as in Example 71.
Comparative Example 35
[0449] The aluminum alloy sheet, JIS 3004H19, having a thickness of
0.26 mm was pre-treated in the same-manner as in Example 72,
subjected to the phenol-type organic surface treatment in the same
manner as in Example 59 and was, thereafter, coated with the resin
and from which the lids were formed and evaluated in the same
manner as in Example 72. Here, however, the surface-treated metal
material was evaluated after it has been subjected to the
phenol-type organic surface treatment.
Comparative Example 36
[0450] The aluminum alloy sheet, JIS 3004H19, having a thickness of
0.26 mm was pre-treated in the same manner as in Example 72,
subjected to the inorganic surface treatment in the same manner as
in Comparative Example 34 and was, thereafter, coated with the
resin and from which the lids were formed and evaluated in the same
manner as in Example 7.2.
Comparative Example 37
[0451] The metal material was coated with the resin and from which
the lids were formed and evaluated in the same manner as in Example
71 but using a surface-treated metal material obtained by
conducting the cathodic electrolysis in the treating bath Y of
Table 10 at a current density of 2 A/dm.sup.2 for 9 seconds.
Comparative Example 38
[0452] The metal material was coated with the resin and from which
the lids were formed and evaluated in the same manner as in Example
72 but using the surface-treated metal material obtained by
conducting the cathodic electrolysis in the treating bath Y of
Table 10 at a current density of 2 A/dm.sup.2 for 9 seconds.
Comparative Example 39
[0453] The surface-treated metal material was coated with the
resin, and from which the lids were formed and evaluated in the
same manner as in Example 71 but treating the metal sheet and
forming the inorganic surface-treating layer thereon in the same
manner as in Example 71, and forming a silane coupling agent layer
having a thickness calculated as Si of 50 mg/m.sup.2 on the
inorganic-treating layer in the same manner as in Comparative
Example 0.32.
Comparative Example 40
[0454] The surface-treated metal material was coated with the
resin, and from which the lids were formed and evaluated in the
same manner as in Example 72 but treating the metal sheet and
forming the inorganic surface-treating layer thereon in the same
manner as in Example 72, and forming a silane coupling agent layer
having a thickness calculated as Si of 50 mg/m.sup.2 on the
inorganic-treating layer in the same manner as in Comparative
Example 32.
Comparative Example 41
[0455] The metal sheet was coated with the resin and from which the
lids were formed and evaluated in the same manner as in Example 7.1
but forming an aqueous solution containing sulfuric acid in an
amount of 15% by weight, forming an opposing electrode by using an
aluminum sheet, conducting the anodic oxidation treatment at a
solution temperature of 40.degree. C. for 15 seconds maintaining a
voltage of 15 V, immediately followed by the after-treatment, i.e.,
washing with water, with pure water and drying.
Comparative Example 42
[0456] The surface-treated metal material was coated with the
resin, and from which the lids were formed and evaluated in the
same manner as in Example 72 but conducting the anodic oxidation
treatment in the same manner as in Comparative Example 41.
Evaluation of Real Cans
Example 75
1. Formation of a Surface-Treated Metal Material
[0457] As a metal sheet, a cold-rolled steel sheet having a
thickness of 0.22 mm and a tempering degree of DR8 was pretreated,
i.e., treated with an acid, washed with water and, then, with pure
water. The metal sheet was further treated in the same manner as in
Example 41 but conducting the cathodic electrolysis in a treating
bath O of Table 10 at a current density of 1 A/dm.sup.2 flowing the
current for 0.6 seconds and halting the current for 0.4 seconds
repetitively 12 times. Thereafter, the metal sheet was dipped in an
aqueous solution of 3% .gamma.-aminopropyltrimethoxysilane (product
name, KBM903, produced by Shin-Etsu Kagaku Kogyo Co.), squeezed by
using the rolls and was dried at 120.degree. C. for one minute to
obtain a surface-treated metal material having a silane coupling
agent layer of a thickness calculated as Si of 5 mg/m/z formed on
the inorganic-treating layer.
2. Formation of a Resin-Coated Metal Material
[0458] The thus obtained surface-treated metal material was heated
at 250.degree. C., the lower layer side of the cast film (h) shown
in Table 0.12 was thermally press-adhered onto one surface of the
metal sheet, the east film (j) of Table 12 was thermally
press-adhered onto another one surface thereof that became the
outer surface side by using the laminating rolls, and the films
were immediately cooled with water to obtain a resin-coated metal
material.
3. Formation of Can Walls and Can Lids
[0459] A lubricating agent for working was applied onto the
obtained resin-coated metal sheet which was, then, redrawn (drawing
ratio of 2.5) to form a can wall of an inner diameter of 65.3 mm,
Next, the can wall was heat-treated at 220.degree. C. for 60
seconds to remove distortion from the resin film, followed by
trimming for the opening end and flanging to form a deeply drawn
can having a height of 101.1 mm. By using part of the thus obtained
resin-coated metal sheet, on the other hand, a full-open lid of a
211-diameter was formed according to an established method.
4. Content Filling Test
[0460] To test the thus formed can wall and can lid, the can wail
was filled with a meat sauce, the full-open lid was double-seamed
therewith, and the retort sterilization treatment was conducted at
120.degree. C. for 30 minutes.
5. Evaluation of the Surface-Treated Metal Material
[0461] Part of the inorganic surface-treated metal material of
before being subjected to the organic surface treatment was
measured for its weight film thickness and surface atomic ratios in
the same manner as in Example 41. The results were as shown in
Table 0.16.
6. Evaluation of the Containers
[0462] The containers that were formed were examined for their
state of organic coating to observe any abnormal condition such as
exfoliation and pitting. Further, after filled with the contents,
the containers were preserved at 37.degree. C. for 6 months, and
were opened to examine the corrosion and floating of the organic
coating on the inner surface side of the containers. The results
were as shown in Table 16.
Example 76
1. Formation of a Surface-Treated Metal Material
[0463] As a metal sheet, a cold-rolled steel sheet having a
thickness of 0.17 mm and a tempering degree of DR8 was pretreated,
i.e., electrolytically dewaxed, washed with water and, then, with
pure water. The metal sheet was, then, plated with nickel in an
amount of 0.3 g/m.sup.2 on each surface, plated with tin in an
amount of 0.6 g/m.sup.2 on each surface, and was ref low-treated to
form a nickel-tin-iron alloy layer. Thereafter, the metal sheet was
subjected to the cathodic electrolysis in the treating bath O of
Table 10 and to the treatment with the silane coupling agent in the
same manner as in Example 75 to obtain a surface-treated metal
material,
2. Formation of a Resin-Coated Metal Material
[0464] The thus obtained surface-treated metal material was
roll-coated on both surfaces thereof with the epoxyacrylic aqueous
coating material in such a manner that the thickness of the coating
after baked was 10 .mu.m, and was baked at 200.degree. C. for 10
minutes to obtain a resin-coated metal material.
3. Formation of Can Walls and Can Lids
[0465] A lubricating agent for working was applied onto the
obtained resin-coated metal material which was, then, drawn
(drawing ratio of 1.3) to form a can wall of an inner diameter of
83.3 mm, which was, thereafter, followed by trimming for the
opening end and flanging to form a drawn can having a height of
45.5 mm. By using part of the thus obtained resin-coated metal
sheet, on the other hand, a full-open lid of a 307-diameter was
formed according to an established method.
4. Content Filling Test
[0466] To test the thus formed can wall and can lid, the can wall
was filled with a tuna pickle in oil, the full-open lid was
double-seamed therewith, and the retort sterilization treatment was
conducted at 115.degree. C. for 60 minutes.
5. Evaluation of the Surface-Treated Metal Material
[0467] The inorganic surface-treating layer was measured for its
weight film thickness and surface atomic ratios in the same manner
as In Example 75.
6. Evaluation of the Containers
[0468] The containers were evaluated in the same manner as in
Example 75 but, further, examining for their discoloration due to
vulcanization after the cans were opened.
Example 77
1. Formation of a Surface-Treated Metal Sheet
[0469] As a metal sheet, a cold-rolled steel sheet having a
thickness of 0.22 mm and a tempering degree of T4 was pre-treated,
i.e., electrolytically dewaxed, washed with an acid, washed with
water, washed with pure water and was, then, plated with tin in an
amount of 2.0 g/m.sup.2 on each surface and was ref low-treated,
followed by the cathodic treatment in the same manner as in Example
41 but conducting the cathodic electrolysis in the treating bath L
of Table 10 at a current density of 0.6 A/dm.sup.2 flowing the
current for 0.6 seconds and halting the current for 0.4 seconds
repetitively 0.16 times to thereby obtain a surface-treated metal
material for producing can walls.
[0470] Further, a cold-rolled steel sheet having a thickness of
0.21 mm and a tempering degree of T4, too, was treated in the same
manner as described above to obtain a surf ace-treated metal sheet
for producing can lids.
2. Formation of a Resin-Coated Metal Material, Can Walls and Can
Lids
[0471] The surface-treated metal sheet for producing can walls was
marginally coated with an epoxyacrylic aqueous coating material
except those portions corresponding to the seam portions of the can
wall in a manner that the film thicknesses after baking were 5
.mu.m on the inner surface side and 3 .mu.m on the outer surface
side, and was cured by baking in a hot air drying furnace for 10
minutes to obtain a resin-coated metal material. The resin-coated
metal material was cut into a blank which was welded into a
cylindrical shape by using a commercially available
electric-resistance welding machine that uses a wire electrode.
Next, the inner and outer surfaces of the weld-seamed portions of
the can wall were spray-coated with a solvent-type epoxyurea
repairing material in a manner that the film thickness after dried
was 40 .mu.m, followed by baking in the hot air drying furnace for
3 minutes in order to obtain a welded can wall (can diameter of
65.4 mm and a can wall height of 122 mm) coating the seamed
portions.
[0472] The surface-treated metal material for producing can lids,
on the other hand, was roll-coated on both surfaces thereof with an
epoxyacrylic aqueous coating material in a manner that the
thickness of coating after baked was 10 .mu.m followed by baking at
200.degree. C. for 10 minutes to form a shell lid having a
209-diameter relying on an established method.
[0473] One open end of the can wall was subjected to the flanging
and the necking, and the above lid of the 209-diameter was
wrap-seamed therewith while the other open end thereof was
subjected to the triple necking and flanging.
3. Content Filling Test
[0474] The can wall was filled with a coffee at 50.degree. C., and
a 206-diameter aluminum SOT lid was double-seamed therewith, and
the retort sterilization treatment was conducted at 125.degree. C.
for 25 minutes.
4. Evaluation of the Surface-Treated Metal Material
[0475] The surface-treated metal material was measured for its
weight film thicknesses and surface atomic ratios in the same
manner as in Example 75.
5. Evaluation of the Containers
[0476] The containers were evaluated in the same manner as in
Example 75 but, further, measuring the amount of iron elution after
the cans were opened.
Example 78
1. Formation of the Surface-Treated Metal Material
[0477] A surface-treated steel sheet for producing can walls was
obtained by treating the steel sheet in the same manner as in
Example 77 but plating tin in an amount of 11.2 g/m.sup.2 on each
surface and effecting the ref low-treatment. On the other hand, the
surface-treated metal material for producing can lids was the same
sheet as the sheet treated in Example 77.
2. Formation of a Resin-Coated Metal Material, Can Walls and Can
Lids
[0478] The surface-treated metal sheet for producing can walls was
cut into a blank without being coated. The blank was welded Into a
cylindrical shape by using a commercially available
electric-resistance welding machine that uses a wire electrode.
Next, the inner and outer surfaces of the weld-seamed portions of
the can wall were spray-coated with a solvent-type epoxyurea
repairing material in a manner that the film thickness after dried
was 40 .mu.m, followed by baking in the hot air drying furnace for
3 minutes in order to obtain a can wall (can diameter of 74.1 mm
and a can wall height of 81.2 mm) coating the seamed portions.
[0479] The surface-treated metal material for producing can lids,
on the other hand, was roll-coated on both surfaces thereof with an
epoxyacrylic aqueous coating material in a manner that the
thickness of coating after baked was 10 .mu.m followed by baking at
200.degree. C. for 10 minutes to form a shell lid having a
301-diameter relying on an established method.
[0480] One open end of the can wall was subjected to the flanging
and the necking, and the above lid of the 301-diameter was
wrap-seamed therewith while the other open end thereof was
subjected to the triple necking and flanging.
3. Content Filling Test
[0481] The can wall was hot-packed with an orange preserved in
syrup, and the 301-diameter lid was double-seamed therewith, and
the hot-water sterilization treatment was conducted.
4. Evaluation of the Surface-Treated Metal Material
[0482] The surface-treated metal material was measured for its
weight film thicknesses and surface atomic ratios in the same
manner as in Example 75.
5. Evaluation of the Containers
[0483] After preserved at 37.degree. C. for 6 months, the
Containers were evaluated in the same manner as in Example 75 but
further evaluating if the inner surfaces of the containers were
non-uniformly discolored and if the contents were turning into
brown color.
Example 79
1. Formation of a Surface-Treated Metal Sheet
[0484] As a metal sheet, a cold-rolled steel sheet having a
thickness of 0.22 mm and a tempering degree of T4 was pre-treated,
i.e., electrolytically dewaxed, washed with an acid, washed with
water, washed with pure water and was, then, plated with nickel in
an amount of 0.03 g/m.sup.2 on each surface, was plated with tin in
an amount of 1.3 g/m.sup.2 on each surface, and was reflow-treated,
followed by the cathodic treatment in the treating bath L of Table
10 in the same manner as in Example 77 to thereby obtain a
surface-treated metal material for producing can walls.
[0485] Further, a cold-rolled steel sheet having a thickness of
0.21 mm and a tempering degree of T4, too, was treated in the same
manner as described above to obtain a surface-treated metal sheet
for producing can lids.
2. Formation of a Resin-Coated Metal Material, Can Walls and Can
Lids
[0486] The surface-treated metal material for producing can walls
was marginally coated with an epoxyphenol solvent-type coating
material except those portions corresponding to the seam portions
of the can wall in a manner that the film thicknesses after baking
were 5 .mu.m on the inner surface side and 3 .mu.m on the outer
surface side, and was cured by baking in a hot air drying furnace
for 10 minutes to obtain a resin-coated metal material. The
resin-coated metal material was cut into a blank which was welded
into a cylindrical shape by using a commercially, available
electric-resistance welding machine that uses a wire electrode.
Next, the inner and outer surfaces of the weld-seamed portions of
the can wall were spray-coated with a solvent-type epoxyurea
repairing material in a manner that the film thickness after dried
was 40 .mu.m, followed toy baking in the hot air drying furnace for
3 minutes in order to obtain a welded can wall (can diameter of
65.4 mm and a can wall height of 122 mm) coating the seamed
portions.
[0487] The surface-treated metal material for producing can lids,
on the other hand, was roll-coated on both surfaces thereof with an
epoxyphenol solvent-type coating material in a manner that the
thickness of coating after baked was 10 .mu.m followed by baking at
200.degree. C. for 10 minutes to form a shell lid having a
209-diameter relying on an established method.
[0488] One open end of the can wall was subjected to the flanging
and the necking, and the above lid of the 209-diameter was
wrap-seamed therewith while the other open end thereof was
subjected to the triple necking and flanging.
3. Content Filling Test
[0489] The can wall was hot-packed with an orange juice at
93.degree. C., and a commercially available 206-diameter aluminum
SOT lid was double-seamed therewith to seal.
4. Evaluation of the Surface-Treated Metal Material
[0490] The surface-treated metal material was measured for its
weight film thicknesses and surface atomic ratios in the same
manner as in Example 75.
5. Evaluation of the Containers
[0491] The containers were evaluated in the same manner as in
Example 77.
Example 80
1. Formation of a Surface-Treated Metal Sheet
[0492] As a metal sheet, a cold-rolled steel sheet having a
thickness of 0.195 mm and a tempering degree of T3 was pre-treated,
i.e., eleetrolytically dewaxed, washed with an acid, washed with
water, washed with pure water and was, then, plated with tin in an
amount of 1.0 g/m.sup.2 on each surface, followed by the cathodic
treatment in the treating bath L of Table 10 in the same manner as
in Example 77 to thereby obtain a surface-treated metal material
for producing can walls.
[0493] Further, a surf ace-treated metal material for producing can
lids was obtained in the same manner as in Example 71 but using, as
a metal sheet, an aluminum alloy sheet, JIS 5182H19, having a
thickness of 0.285 mm and conducting the cathodic electrolysis in
the treating bath L of Table 10 at a current density of 5
A/dm.sup.2 flowing the current for 0.6 seconds and halting the
current for 0.4 seconds repetitively 0.8 times,
2. Formation of a Resin-Coated Metal Material
[0494] The thus obtained surface-treated metal material for
producing can walls and can lids was heated at 220.degree. C., the
lower layer side of the cast film (l) shown in Table 12 was
thermally press-adhered onto one surface of the metal material, the
cast film (k) of Table 12 was thermally press-adhered onto another
one surface thereof that became the outer surface side by using the
laminating rolls, and the films were immediately cooled with water
to obtain a resin-coated metal material.
3. Formation of the Can Walls and Can Lids
[0495] A paraffin wax was electrostatically applied onto both
surfaces of the resin-coated metal material for producing can
walls, which was, then, punched into a circular shape of a diameter
of 140 mm and from which a shallowly drawn cup was formed relying
on an established method. The thus drawn cup was subjected to the
redraw/ironing working two times repetitively to form a deeply
drawn and ironed cup having a small diameter and a large height,
the thus obtained cup possessed the following characteristics.
TABLE-US-00018 Cup diameter 52 mm Cup height 138 mm Thickness of
can wall relative to the -50% initial sheet thickness
[0496] After subjected to the doming, the cup was heat-treated at
220.degree. C. for 60 seconds to remove distortion from the resin
film, followed by trimming for the opening end, printing on the
curved surface, necking for forming a 200-diameter, flanging and
re-flanging to obtain a 250-g seamless can.
[0497] From the resin-coated metal material for producing can lids,
further, SOT lids of a 200-diameter were formed.
4. Content Filling Test
[0498] The above 250-g can was cold-packed with a coke at 5.degree.
C., and, immediately thereafter, the above SOT lid was
double-seamed therewith to seal.
5. Evaluation of the Surface-Treated Metal Material
[0499] The surface-treated metal material was measured for its
weight film thicknesses and surface atomic ratios in the same
manner as in Example 75.
5. Evaluation of the Containers
[0500] The containers were evaluated in the same manner as in
Example 77.
Example 81
1. Formation of a Surface-Treated Metal Material and a Resin-Coated
Metal Material
[0501] An aluminum alloy sheet, JIS 3004H19, having a thickness of
0.28 mm was used as a metal sheet for producing can walls and an
aluminum alloy sheet, JIS 5182H19, having a thickness of 0.25 mm
was used as a metal sheet for producing can lids. These aluminum
alloy sheets were pre-treated in the same manner as in Example 72
but intermittently conducting the cathodic electrolysis in the
treating bath L of Table 10 at a current density of 10 A/dm.sup.2
and flowing the current for 0.4 seconds and halting the current for
0.6 seconds repetitively 2 times to obtain a surface-treated
aluminum sheet. The resin coatings were formed in the same manner
as in Example 75 but coating both surfaces with the cast film (m)
of Table 12,
[0502] A paraffin wax was electrostatically applied onto both
surfaces of the resin-coated metal material for producing can
walls, which was, then, punched into a circular shape of a diameter
of 166 mm and from which a shallowly drawn cup was formed relying
on an established method. The thus shallowly drawn cup was
subjected to the redraw/ironing working and to the
deep-draw/ironing working to form a can body. The thus obtained can
body possessed the following characteristics.
TABLE-US-00019 Can body diameter 66 mm Can body height 128 mm
Thickness of can wall relative to the -63% initial sheet
thickness
[0503] After subjected to the doming, the can body was heat-treated
at 220.degree. C. for 60 seconds to remove distortion from the
resin film, followed by trimming for the opening end, printing on
the curved surface, necking for forming a 206-diameter, flanging
and re-flanging to obtain a 350-g seamless can according to an
established method. From the resin-coated metal material for
producing can lids, further, SOT lids of a 206-diameter were formed
according to an established method.
2. Content Filling Test
[0504] The above 350-g can was cold-packed with a beer at 5.degree.
C., and the above SOT was double-seamed therewith to seal,
3. Evaluation of the Surface-Treated Metal Material
[0505] The surface-treated metal material was measured for its
weight film thicknesses and surface atomic ratios in the same
manner, as in Example 75.
4. Evaluation of the Containers
[0506] The containers were evaluated in the same manner as in
Example 72 but further measuring the amount of aluminum elution
after the containers were opened. Table 10.
TABLE-US-00020 TABLE 10 Treating Al Zr Ti F B bath mol/l mol/l mo/l
mo/l mo/l L 0.02 -- -- -- -- M 0.02 -- -- 0.02 0.05 N 0.01 -- -- --
-- O 0.01 -- -- 0.02 0.05 P 0.01 -- -- 0.15 -- Q 0.01 -- -- 0.07 --
R 0.02 -- -- -- -- S 0.02 -- -- -- -- T 0.01 -- -- 0.01 -- U 0.01
0.003 -- -- -- V 0.01 -- 0.004 -- -- W 0.02 0.003 0.003 -- -- X
0.04 -- -- 0.01 -- Y 0.07 -- -- -- -- Z 0.01 -- -- 0.25 --
TABLE-US-00021 TABLE 11 Polyester component Titanium Copolymerized
Ionomer Tocopherol dioxide Copolymerrizable ratio Content, Content,
Content, Content, component mol % wt % wt % wt % wt % G isophthalic
12 100 -- -- -- acid H isophthalic 5 100 -- -- -- acid I
isophthalic 5 84 15 1 1 acid J isophthalic 12 75 -- -- -- acid K
isophthalic 15 84 15 1 1 acid L isophthalic 15 100 -- -- --
acid
TABLE-US-00022 TABLE 12 Surface layer Lower layer Resin Thickness
Resin Thickness composition (.mu.m) composition (.mu.m) (h) B 5 C
25 (i) C 30 -- -- (j) A 5 D 10 (k) B 5 E 25 (l) B 5 E 10 (m) B 5 F
10 (n) F 30 -- --
TABLE-US-00023 TABLE 13 Wt. film thickness Surface Surface
(mg/m.sup.2) atomic ratio exposure Al Zr Ti O/M F/M (P + S)/M ratio
(Sn %) Ex. 41 14 -- -- 2.23 0.11 0.00 1.5 Ex. 42 28 -- -- 1.80 0.60
0.00 1.2 Ex. 43 15 -- -- 2.36 0.06 0.00 1.3 Ex. 44 15 -- -- 2.25
0.06 0.00 0.5 Ex. 45 37 -- -- 1.90 1.02 0.00 0.3 Ex. 46 9 -- --
1.92 0.76 0.00 0.3 Ex. 47 42 -- -- 1.74 0.42 0.00 0.2 Ex. 48 14 --
-- 1.65 1.10 0.00 0.6 Ex. 49 42 -- -- 1.83 2.25 0.00 0.3 Ex. 50 75
-- -- 2.23 1.92 0.00 0.1 Ex. 51 30 -- -- 3.06 0.03 0.18 1.6 Ex. 52
50 -- -- 5.13 0.00 1.00 0.9 Ex. 53 25 -- -- 3.28 0.36 0.19 0.2 Ex.
54 12 6 -- 2.85 0.42 0.00 1.2 Ex. 55 18 -- 5 3.12 0.35 0.00 1.7 Ex.
56 26 10 8 3.32 0.56 0.00 0.8 Ex. 57 43 -- -- 4.25 0.32 0.00 3.5
Ex. 58 25 -- -- 1.76 1.92 0.00 0.8 Comp. Ex. 25 175 -- -- 3.22 1.85
0.00 0.1 Comp. Ex. 26 15 -- -- 5.73 0.00 1.19 7.0 Comp. Ex. 27 10
-- -- 6.07 0.02 1.30 5.5 Comp. Ex. 28 12 -- -- 2.85 3.33 0.00 4.5
Comp. Ex. 29 -- -- -- -- -- -- -- Comp. Ex. 30 -- -- -- -- -- -- --
Comp. Ex. 31 -- 26 -- 4.17 0.95 0.00 22.0 Properties Vulcan-
Adhesive Corrosion ization Kind of property resistance resistance
Color treatment Ex. 41 .largecircle. .largecircle. .largecircle.
.largecircle. non-chrome Ex. 42 .circleincircle. .circleincircle.
.largecircle. .largecircle. non-chrome Ex. 43 .largecircle.
.largecircle. .circleincircle. .largecircle. non-chrome Ex. 44
.largecircle. .largecircle. .circleincircle. .largecircle.
non-chrome Ex. 45 .circleincircle. .largecircle. .circleincircle.
.largecircle. non-chrome Ex. 46 .largecircle. .largecircle.
.circleincircle. .largecircle. non-chrome Ex. 47 .circleincircle.
.circleincircle. .largecircle. .largecircle. non-chrome Ex. 48
.circleincircle. .largecircle. .circleincircle. .largecircle.
non-chrome Ex. 49 .circleincircle. .largecircle. .circleincircle.
.largecircle. non-chrome Ex. 50 .largecircle. .largecircle.
.largecircle. .largecircle. non-chrome Ex. 51 .largecircle.
.largecircle. .largecircle. .largecircle. non-chrome Ex. 52
.largecircle. .largecircle. .largecircle. .largecircle. non-chrome
Ex. 53 .largecircle. .largecircle. .largecircle. .largecircle.
non-chrome Ex. 54 .largecircle. .largecircle. .largecircle.
.largecircle. non-chrome Ex. 55 .largecircle. .circleincircle.
.largecircle. .largecircle. non-chrome Ex. 56 .largecircle.
.largecircle. .largecircle. .largecircle. non-chrome Ex. 57 .DELTA.
.largecircle. .largecircle. .largecircle. non-chrome Ex. 58
.largecircle. .circleincircle. .largecircle. .largecircle.
non-chrome Comp. Ex. 25 .DELTA. .largecircle. .largecircle.
.largecircle. non-chrome Comp. Ex. 26 .DELTA. .DELTA. .largecircle.
.largecircle. non-chrome Comp. Ex. 27 .DELTA. .DELTA. .largecircle.
.largecircle. non-chrome Comp. Ex. 28 .DELTA. .DELTA. .largecircle.
.largecircle. non-chrome Comp. Ex. 29 .largecircle. .DELTA.
.largecircle. .largecircle. chrome Comp. Ex. 30 .largecircle.
.largecircle. .largecircle. .largecircle. chrome Comp. Ex. 31 -- --
-- X non-chrome
TABLE-US-00024 TABLE 14 Properties Adhesive Corrosion Vulcanization
property resistance resistance Ex. 59 .largecircle. .largecircle.
.circleincircle. Ex. 60 .circleincircle. .circleincircle.
.circleincircle. Ex. 61 .circleincircle. .circleincircle.
.circleincircle. Ex. 62 .largecircle. .largecircle.
.circleincircle. Ex. 63 .circleincircle. .circleincircle.
.circleincircle. Ex. 64 .circleincircle. .largecircle.
.circleincircle. Ex. 65 .circleincircle. .largecircle.
.circleincircle. Ex. 66 .circleincircle. .largecircle.
.circleincircle. Ex. 67 .largecircle. .largecircle.
.circleincircle. Ex. 68 .largecircle. .largecircle.
.circleincircle. Ex. 69 .largecircle. .largecircle.
.circleincircle. Ex. 70 .largecircle. .largecircle.
.circleincircle. Comp. ex. 32 .circleincircle. X .largecircle.
TABLE-US-00025 TABLE 15 Film thickness (mg/m.sup.2) Surface atomic
ratio Al Zr O/M F/M (P + S)/M Ex. 71, 72 32 -- 1.83 1.73 0.00 Ex.
73, 74 32 -- 1.83 1.73 0.00 Comp. Ex. 33, 35 -- 5 6.00 0.50 1.20
Comp. Ex. 34, 36 -- 9 9.10 0.50 1.10 Comp. Ex. 37, 38 55 -- 5.67
0.02 0.00 Comp. Ex. 39, 40 32 -- 1.83 1.73 0.00 Comp. Ex. 41, 42 23
-- 2.20 0.03 0.09 Properties Close adhesion Adhesive Lid in hot
water Corrosion property openability water resistance Ex. 71, 72
.largecircle. .largecircle. .circleincircle. .largecircle. Ex. 73,
74 .circleincircle. .circleincircle. .circleincircle. .largecircle.
Comp. Ex. 33, 35 X X X X Comp. Ex. 34, 36 X X X X Comp. Ex. 37, 38
X X X X Comp. Ex. 39, 40 .largecircle. X X .largecircle. Comp. Ex.
41, 42 X X X X M is an element (Al or Zr) representing the film
thickness.
TABLE-US-00026 TABLE 16 Al film Surface thickness atomic ratio Use
(mg/m.sup.2) O/Al F/Al (P + S)/Al Ex. 75 can wall, 42 1.54 1.06
0.00 lid Ex. 76 can wall, 35 1.66 1.16 0.00 lid Ex. 77 wall 22 2.08
0.12 0.00 lid 31 1.92 0.11 0.00 Ex. 78 wall 15 1.97 0.13 0.00 lid
31 1.92 0.11 0.00 Ex. 79 wall 35 2.33 0.15 0.00 lid 43 2.47 0.11
000 Ex. 80 wall 30 1.83 0.14 0.00 lid 45 2.26 0.12 0.00 Ex. 81 wall
21 2.45 0.14 0.00 lid 45 2.38 0.16 0.00 Evaluation of Container
container property form- Inner surface of container ability State
Color of Color Metal State of State of of org. inner of the elution
org. film corrosion film surface content (ppm) Ex. 75 normal normal
normal -- -- -- Ex. 76 normal normal normal normal -- -- Ex. 77
normal normal normal -- -- 0.00 Ex. 78 normal normal -- -- normal
-- Ex. 79 normal normal normal -- -- 0.05 Ex. 80 normal normal
normal -- -- 0.00 Ex. 81 normal normal normal -- -- 0.00
INDUSTRIAL APPLICABILITY
[0507] The surface-treated metal material and the resin-coated
metal material of the present invention can be effectively used,
particularly, for the metal cans and can lids, as well as for
automobiles, household electric appliances and building
materials.
[0508] The surface treating method of the invention can also be
applied to such surface-treated steel-sheets as tin-plated steel
sheets and zinc-plated steel sheets in addition to aluminum sheets
and steel sheets. By applying to, for example, the zinc-plated
steel sheets and the tin-plated steel sheets, for example, there
can be obtained such synergistic effects as preventing zinc and tin
from corroding while imparting close adhesion and corrosion
resistance due to the non-chrome surface treatment. Therefore, a
variety of kinds of base members can be treated to offer
surface-treated steel sheets that can be used in a wide range of
applications.
* * * * *