U.S. patent application number 10/508999 was filed with the patent office on 2005-06-02 for metal soap-coated particle article made with the same process for production lubricating coating agent and lubricating film.
Invention is credited to Komiyama, Shinobu, Yamaguchi, Hidehiro, Yoshida, Masayuki.
Application Number | 20050119133 10/508999 |
Document ID | / |
Family ID | 28449192 |
Filed Date | 2005-06-02 |
United States Patent
Application |
20050119133 |
Kind Code |
A1 |
Komiyama, Shinobu ; et
al. |
June 2, 2005 |
Metal soap-coated particle article made with the same process for
production lubricating coating agent and lubricating film
Abstract
Particles each of which consists of an inorganic polyvalent
metal compound as a nucleus and a coating of a metallic soap of the
polyvalent metal coating the nucleus (coated particles); products
and preparation processes using the particles; a lubricating
coating forming agent wherein particles each of which consists of a
polyvalent metal salt of phosphoric acid as a nucleus and a coating
of a metallic soap of the polyvalent metal coating the surface of
the nucleus are suspended in an aqueous solution of a water soluble
inorganic salt and/or a water soluble organic acid salt; and a
lubricating coating. The coated particles are novel particles which
can be used as an ingredient of coating-type lubricating coating;
are excellent in seizure resistance; can inhibit wear of tools at
the time of plastic working since the friction coefficient of the
surface of the particles is low; and are slow to cause pollution of
working oils. Lubricating coating obtained by applying the
lubricating coating forming agent onto the surface of a metallic
material gives excellent cold plastic working properties, namely
lubricity and seizure resistance to the metallic material.
Inventors: |
Komiyama, Shinobu; (Tokyo,
JP) ; Yoshida, Masayuki; (Tokyo, JP) ;
Yamaguchi, Hidehiro; (Tokyo, JP) |
Correspondence
Address: |
NIXON & VANDERHYE, PC
1100 N GLEBE ROAD
8TH FLOOR
ARLINGTON
VA
22201-4714
US
|
Family ID: |
28449192 |
Appl. No.: |
10/508999 |
Filed: |
September 27, 2004 |
PCT Filed: |
March 24, 2003 |
PCT NO: |
PCT/JP03/03511 |
Current U.S.
Class: |
508/100 ;
508/108 |
Current CPC
Class: |
C10M 2207/1203 20130101;
C10M 2201/0853 20130101; C10N 2010/04 20130101; C10M 169/04
20130101; C10M 173/02 20130101; C10M 2207/12 20130101; C10N 2050/08
20130101; C10N 2030/06 20130101; C10N 2040/24 20130101; C10M
2207/1253 20130101; C10M 2201/0623 20130101; C10N 2020/061
20200501; C10M 2201/085 20130101; C10N 2040/243 20200501; C10M
2207/126 20130101; C10M 2201/085 20130101; C10M 2207/12 20130101;
C10M 2201/085 20130101; C10M 2207/125 20130101; C10M 2201/085
20130101; C10N 2010/04 20130101; C10M 2201/085 20130101; C10N
2010/04 20130101 |
Class at
Publication: |
508/100 ;
508/108 |
International
Class: |
C10M 169/04; C10M
173/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 25, 2002 |
JP |
2002-83906 |
Claims
1-25. (canceled)
26. Particles each of which consists of an inorganic polyvalent
metal compound as a nucleus and a coating of a metallic soap of the
polyvalent metal coating the surface of the nucleus, the inorganic
polyvalent metal compound being water sparingly soluble or water
insoluble and having reactivity with an alkali metal salt, ammonium
salt or water soluble ester of a fatty acid.
27. The particles according to claim 26 which has an average
particle size of 300 .mu.m or less and wherein the proportion of
all the metallic soap coatings to all the particles is 1 to 30% by
mass.
28. The particles according to claim 26 wherein the polyvalent
metal in the inorganic polyvalent metal compound is at least one
selected from Zn, Fe, Mn, Ni, Co, Ca, Mg, Ba, Al and Sn.
29. The particles according to claim 26 wherein the inorganic
polyvalent metal compound is an oxide, hydroxide, carbonate or
phosphate of the polyvalent metal.
30. The particles according to claim 26 wherein the inorganic
polyvalent metal compound is zinc oxide or zinc phosphate.
31. Particles each of which consists of each of the particles
according to claim 26 and a coating of an alkali metal salt,
ammonium salt or water soluble ester of a fatty acid coating the
surface of the particle.
32. The particles according to claim 31 which has an average
particle size of 300 .mu.m or less and wherein the proportion of
all the metallic soap coatings to all the particles is 1 to 30% by
mass and the proportion of all the coatings of the alkali metal
salt, ammonium salt or water soluble ester of the fatty acid to all
the particles is 0.1 to 5% by mass.
33. Powder consisting of the particles according to claim 26.
34. Powder consisting of the particles according to claim 31.
35. A suspension wherein the particles according to claim 26 are
suspended in water or an aqueous solution of an alkali metal salt,
ammonium salt or water soluble ester of a fatty acid, the average
particle size of particles of the inorganic polyvalent metal
compound being 20 .mu.m or less, the proportion of all the metallic
soap coatings to all the particles being 1 to 30% by mass.
36. A process for preparing the powder according to claim 34 which
comprises mixing an inorganic polyvalent metal compound with an
alkali metal salt, ammonium salt or water soluble ester of a fatty
acid in water at an elevated temperature, and then drying the
resulting suspension, the inorganic polyvalent metal compound being
water sparingly soluble or water insoluble and having reactivity
with the alkali metal salt, ammonium salt or water soluble ester of
the fatty acid.
37. A process for preparing the suspension according to claim 35
which comprises mixing an inorganic polyvalent metal compound with
an alkali metal salt, ammonium salt or water soluble ester of a
fatty acid in water at an elevated temperature, the inorganic
polyvalent metal compound being water sparingly soluble or water
insoluble and having reactivity with the alkali metal salt,
ammonium salt or water soluble ester of the fatty acid.
38. Lubricating coating containing the particles according to claim
26 in an amount of 1% by mass or more.
39. The lubricating coating according to claim 38 whose dry coating
thickness is 0.5 to 50 .mu.m.
40. Lubricating coating containing the particles according to claim
31 in an amount of 1% by mass or more.
41. The lubricating coating according to claim 40 whose dry coating
thickness is 0.5 to 50 .mu.m.
42. A lubricating coating forming agent wherein particles each of
which consists of a water sparingly soluble or water insoluble
polyvalent metal salt of phosphoric acid (hereinafter merely
referred to as polyvalent metal salt of phosphoric acid) as a
nucleus and a coating of a metallic soap of the polyvalent metal
coating the surface of the nucleus (the particles being hereinafter
referred to as particles of coated polyvalent metal salt of
phosphoric acid) are suspended in an aqueous solution of a water
soluble inorganic salt and/or a water soluble organic acid salt;
each of the water soluble inorganic salt and organic acid salt
having a property to form a firm coating when it is uniformly
dissolved in water and the resulting solution is applied onto a
metallic material and dried.
43. The lubricating coating forming agent according to claim 42
wherein the polyvalent metal of the polyvalent metal salt of
phosphoric acid is at least one selected from Zn, Fe, Mn, Ni, Co,
Ca, Al and Sn.
44. The lubricating coating forming agent according to claim 42
wherein the polyvalent metal salt of phosphoric acid is at least
one selected from zinc phosphate, zinc iron phosphate, iron
phosphate, calcium phosphate and calcium hydrogenphosphate.
45. The lubricating coating forming agent according to claim 42
wherein the average particle size of the particles of coated
polyvalent metal salt of phosphoric acid is 30 .mu.m or less, and
the average particle size of the polyvalent metal salt of
phosphoric acid is 20 .mu.m or less.
46. The lubricating coating forming agent according to claim 42
wherein the proportion of all the metallic soap coatings to all the
particles of coated polyvalent metal salt of phosphoric acid is 1
to 30% by mass.
47. The lubricating coating forming agent according to claim 42
wherein the water soluble inorganic salt is at least one selected
from an alkali metal salt of sulfuric acid, an alkali metal salt of
silicic acid and an alkali metal salt of boric acid.
48. The lubricating coating forming agent according to claim 42
wherein the water soluble organic acid salt is at least one
selected from an alkali metal salt of malic acid, an alkali metal
salt of succinic acid, an alkali metal salt of citric acid and an
alkali metal salt of tartaric acid.
49. The lubricating coating forming agent according to claim 42
wherein the proportion by mass of the total of the water soluble
inorganic salt and the water soluble organic acid salt (B) to the
particles of coated polyvalent metal salt of phosphoric acid (A),
namely (B)/(A), in terms of solid matter, is within the range of
0.01 to 20.0.
50. The lubricating coating forming agent according to claim 42
which contains a smectite clay mineral in such an amount that the
proportion by mass of the smectite clay mineral (C) to the
particles of coated polyvalent metal salt of phosphoric acid (A),
namely (C)/(A), in terms of solid matter, is within the range of
0.005 to 0.5.
51. The lubricating coating forming agent according to claim 42
which contains, as an auxiliary lubricating ingredient, at least
one selected from an oil, a soap, a metallic soap, a wax and
polytetrafluoroethylene in such an amount that the proportion by
mass of the auxiliary lubricating ingredient (D) to the particles
of coated polyvalent metal salt of phosphoric acid (A), namely
(D)/(A), in terms of solid matter, is within the range of 0.03 to
18.0.
52.The lubricating coating forming agent according to claim 42
which contains a water soluble or water dispersible organic
macromolecular compound having a molecular weight of 1,000 to
1,000,000 in such an amount that its content in the resulting
coating gets to be within 0.5 to 25% by mass based on the whole dry
coating.
53. Lubricating coating formed using the lubricating coating
forming agent according to claim 42.
Description
TECHNICAL FIELD
[0001] This invention is roughly classified into two relevant
inventions. One is an invention relating to particles of an
inorganic polyvalent metal compound coated with a metallic soap as
a fundamental invention, and their general utilization forms; and
the other is an invention relating to a plastic working lubricant
containing such coated particles as a more practical application
form of such coated particles.
[0002] The invention as a fundamental invention can be used in a
wide range, and relates to metallic soap-coated particles excellent
in seizure resistance and capable of preventing tools from wear and
working oil from pollution at the time of plastic working; powder
or suspension on such particles; a process for preparing the powder
or suspension; and lubricating coating.
[0003] The invention as a more practical applied invention relates
to a lubricating coating forming agent, and, in more detail,
relates to a lubricating coating forming agent giving excellent
workability, namely excellent lubricity and excellent seizure
resistance onto the surfaces of various metallic materials such as,
for example, iron materials, steel materials, stainless steel
materials, aluminum materials, magnesium materials, tin materials
and titanium materials which need to be subjected to cold plastic
working typically including forging, wire drawing, tube reducing
and sheet forming; and lubricating coating.
BACKGROUND ART
[0004] Background Art Particularly about the Present Invention as a
Fundamental Invention
[0005] Metallic soap widely used as various lubricants, etc. plays
an important role in the field of cold plastic working typically
including forging, wire drawing, tube drawing of pipes, sheet
forming, etc. of metallic materials. In this field, metallic soap
has been used from long ago as a lubricating ingredient to lower
the friction coefficient between materials to be wrought and tools
at the time of plastic working and thereby reduce working energy
drastically, and has greatly contributed to development of the cold
plastic working field. For example, as a direct use example of
metallic soap in the plastic working field, there can be mentioned
its utilization in auxiliary lubricants used at wire drawing
working. This is such a technology that when a carrier layer such
as borax coating, slaked lime coating or zinc phosphate coating is
provided on the surface of a wire rod and the rod is subjected to
wire drawing working, immediately before the material to be wrought
passes through the die, an auxiliary lubricant containing a large
amount of a metallic soap is made to adhere onto the material to
give or supplement lubricity; and is a case where powder of the
metallic soap is used in a large amount. In another case, a
coating-type lubricant in which lubricating particles containing a
metallic soap as a main ingredient are suspended in water or an
oil, etc. are used in many combinations with the above-mentioned
carrier layer; and so on, and thus there are many technologies
applying metallic soap in the cold plastic working field.
[0006] However, there are also problems in use of metallic soap. As
one of them, there can be mentioned a case of steel wire for header
working in which wire a carrier layer is provided by lime-type
coating forming treatment, an auxiliary lubricant containing a
metallic soap as a main ingredient is made to adhere thereon, and
lubricating coating is completed by carrying out skin pass wire
drawing working. The resulting lubricating coating-coated steel
wire is subjected to header working in a working oil, but at that
time, the metallic soap in the lubricating coating scraps peeling
off swells or is finely suspended in the working oil to pollute the
working oil extremely. This phenomenon is thought to occur because
adhesion between the carrier layer and the lubricating coating
layer is low.
[0007] On the other hand, as a lubricating coating forming
technology, which is somewhat different from the above technology
directly using metallic soap, but is very interesting in using
metallic soap and very fit for cold plastic working, "phosphating
treatment plus soap treatment" has generally been uses from long
ago in this field. This technology is such that a phosphate salt
coating layer is previously provided onto the surface of a material
to be wrought, the coating layer firmly adhering to the surface as
a reactive chemical conversion coating treatment layer, and then an
aqueous solution of a water soluble fatty acid salt is contacted
with the coating layer at an elevated temperature to form metallic
soap coating containing a reactive soap layer. Since the phosphate
salt coating surface is firmly coated with the metallic soap layer,
this technology has such advantages in comparison with the
above-mentioned "carrier layer plus auxiliary lubricant" that the
technology is fit for comparatively strong working since working
following properties of the lubricating ingredient are good, and
such a phenomenon is hard to cause that the soap and the metallic
soap are isolated from the lubricating coating scraps peeling off
at the time of working and pollute the working oil extremely; and
so on.
[0008] However, since both of the phosphating treatment and the
coating treatment with the metallic soap onto the resulting layer
are coating forming methods utilizing chemical reaction, control of
the chemical reactions and administration activity at the cold
plastic working site are complicated, and when waste water
treatment and plant and equipment investment are included, vast
costs are needed. Furthermore, since the performance of coating
formed greatly varies depending on kinds of steels, surface states
of steel, etc., labor for maintaining stable quality is very large,
and, furthermore, mass formation of industrial wastes is coming to
be a great anxiety on environmental load. Thus, in recent years,
development of a convenient and ecological coating forming process
has positively been attempted.
[0009] Lubricating coating comes in between the material to be
wrought and the tool at the time of plastic working to avoid direct
metal contact between the material to be wrought and the tool, and
such lubricating coating may be liquid or solid. However
practically, liquid lubricants represented by oil-type lubricants,
etc. are often unfit for severe plastic working. The reason is that
the lubricating coating preventing the material to be wrought and
the tool from their direct contact undergoes shear to cause
lubricating coating cutting, and thereby seizure occurs. Thus, even
when a liquid lubricant is used or a lubricating ingredient such as
metallic soap which melts and is liquidized with working heat is
used, it is general to use it in combination with carrier coating
such as phosphate salt coating or borax coating, and thereby, the
lubricating ingredient together with the carrier layer comes in
between the surface of the material to be wrought and the tool at
the time of working, and reduces working force and prevents
seizure. But strictly speaking, since, even in this situation,
lubrication coating cutting occurs between the carrier layer
surface and the tool surface, there sometimes arises a situation
that the tool surface undergoes wear little by little by the
carrier layer having a high friction coefficient and the life of
the tool gets short, which gets to be a problem.
[0010] Furthermore, recently, there is a tendency that by
shortening the step of cold plastic working for the purpose of
heightening productive efficiency, the degree of one working is
heightened, and, even in "phosphating treatment plus soap
treatment", it gets difficult to follow surface area enlargement
with sufficient lubricating layer held.
[0011] As a technology for forming cold plastic working lubricating
coating for solving these problems, a step shortening-type
lubricating coating forming agent, etc. are being developed. This
technology is one capable of giving high cold plastic working
performance by simple steps only to make a liquid coating forming
agent adhere onto the surface of a material to be wrought and dry
the agent. As such an invention, JP 2000-63880 A discloses a
lubricant composition for plastic working of metallic material
which comprises (A) a synthetic resin, (B) a water soluble
inorganic salt and water, (B)/(A) (ratio by weight in terms of
solid matter) being 0.25/1 to 9/1, the synthetic resin dissolving
or being dispersed. It is also disclosed that it is preferred to
further incorporate as a lubricant ingredient at least one selected
from the group consisting of a metallic soap, a wax,
polytetrafluoroethylene and an oil in an amount of 1 to 20% by
mass, and as the water soluble inorganic salt is preferred at least
one selected from the group consisting of a sulfate, a borate,
molybdate, a vanadate and a tungstate. Namely, this invention is
characterized in that a lubricating ingredient such as a metallic
soap or a wax is contained, in a dispersed state, in coating
ingredients capable of becoming a carrier, and is an excellent
technology capable of obtaining lubricating coating having high
working performance simply and with labor saving only by applying
the composition onto the surface of the material to be wrought.
Although metallic soap is often used as the lubricating ingredient,
it is mentioned that, since the metallic soap is immobilized in the
coating by the inorganic salt and/or the resin ingredient, adhesion
of the metallic soap is not influenced by adhesion between layers,
as is the case in "carrier layer plus auxiliary lubricant layer",
the possibility of peeling of the metallic soap alone at the time
of working is generally small. Furthermore, in comparison with the
coating of "phosphate salt plus soap treatment" which is
lubricating coating consisting of a comparatively large size of
crystals of the order of width 200 .mu.m, coating obtained from the
above invention has an advantage that it is possible to adjust the
surface area of the lubricant at will, e.g. by making lubricant
ingredients fine particles, and thus lubricating coating exerting
excellent performance even in strong working where enlargement of
surface area is large is being developed, and the technology
including the above invention is a prospective technology also in
the aspect of lubricating performance. However, even in the case of
the lubricating coating obtained by the above technology, there is
a tendency that the carrier layer of a high friction coefficient
exposed owing to the structure of the coating repeats contact with
the tool to give the tool life bad influence.
[0012] Under such a present state of things, lubricating coating
required in the cold plastic working field is considered to be
lubricating coating which has such fine particle structure that the
lubricant layer coats the carrier layer and strongly adheres to the
carrier layer, and can be obtained by coating-type treatment
without needing complicated treating steps. By this, it gets
possible to realize ecological treatment of shortened steps,
reduction of loads on the tool (i.e., reduction of tool wear),
reduction of pollution of the working oil by lubricating coating
scraps, etc. Development of such an ideal lubricant is a great
problem and is urgently needed.
[0013] Background Art Particularly about the Present Invention as a
More Practical Applied Invention
[0014] In plastic working of metallic material, lubricating coating
is formed on the surface of the material to be wrought, for
preventing seizure and galling formed by direct metal contact
between the material to be wrought and the tool. As lubricating
coating formed on the surface of the material to be wrought, there
are two types, one being lubricating coating formed by making a
lubricant physically adhere to the surface of the material to be
wrought, the other being lubricating coating formed by forming a
chemical conversion coating on the surface of the material to be
wrought through chemical reaction and then applying a
lubricant.
[0015] Lubricants made to adhere onto the surface of the material
to be wrought are inferior, in adhesion, to lubricants used after
formation of a chemical conversion coating on the material to be
wrought, and thus generally used in light working. In use of a
chemical conversion coating, a chemical conversion coating such as
a phosphate coating or an oxalate coating playing a role as a
carrier is formed on the material to be wrought, and then a
lubricant having good slipping properties is applied thereon. This
type of coating has two layer structure consisting of the
conversion coating as a carrier coating and the lubricant coating
and exerts very high seizure resistance, and thus has very widely
been used in the field of plastic working such as wire drawing,
tube reducing and forging. Particularly in a field of severe
working among the plastic working field, a method of using
phosphate coating or oxalate coating as undercoat and applying a
lubricant thereon is being frequently adopted.
[0016] Methods for forming a chemical conversion coating onto a
material to be wrought and applying a lubricant thereon are
classified broadly into two methods. One is a method of making a
lubricant physically adhere onto the chemical conversion coating,
and the other is a method of reacting a lubricant with the surface
of the chemical conversion coating to form lubricating coating.
[0017] As the lubricant of the former made to physically adhere,
there can be mentioned one obtained by adding an extreme pressure
additive into mineral oil, vegetable oil or synthetic oil as a base
oil; one obtained by dissolving or dispersing a solid lubricant
represented by graphite or molybdenum disulfide together with a
binder ingredient in water; etc. Such a lubricant is applied onto
the surface of a material to be wrought which was subjected in
advance to chemical conversion coating treatment, and, in the
application, the oil lubricant is used as such, and the aqueous
lubricant is used, followed by a drying step. These lubricants have
advantages that there is no restriction about their application
method and convenient spray coating or immersion coating can be
used; and complicated liquid control as in chemical conversion
coating treatment is almost unnecessary; etc., but these lubricants
are often used in comparatively light working because of low
lubricity.
[0018] On the other hand, as the lubricant of the latter to react
it with the chemical conversion coating, there can generally be
mentioned reactive soap. This method is a technology which has
generally been used from long ago as "phosphating treatment plus
soap treatment", and according to the method, a chemical conversion
coating is formed on the surface of material to be wrought, and
then an aqueous solution of a water soluble fatty acid salt is
contacted with the coating at elevated temperature to form, on the
coating, metallic soap coating containing the reactive soap. The
composite coating formed according to this method can be adapted to
from light working to comparatively strong working, and is used in
a very wide range of working including forging and tube
reducing.
[0019] However, as to reactive-type chemical conversion coating
treatment and reactive soap treatment, there are two problems in a
broad classification. One is that treatment steps for chemical
conversion coating treatment and soap treatment are complicated;
that very wide space is needed as the treatment space; and that
control of treating steps is very complicated, for example that
control of the concentration and ingredients of the treating
liquid, and temperature control for controlling the reaction are
needed because these treatments utilize chemical reactions. The
other is that the amount of industrial wastes and waste water is
very large, for example that since insoluble salts generally called
sludge are formed in the treating liquid as by-products of the
reactions, it is necessary to discharge them periodically from the
treating liquid, and that since when the treating liquid is used
successively, the ingredient balance of the treating liquid is
spoiled, disposal and renewal of the treating liquid, etc. get
necessary.
[0020] Detailed explanation is made bellow on the former. When
"phosphate treatment plus soap treatment" is taken up as an
example, a material to be wrought is first subjected to the
cleaning step and the descaling step, and then to phosphating
treatment and soap treatment. Since single or multi-stage water
washing steps are necessary among these steps, space of about 7 to
12 vessels gets necessary as treating vessel space. Furthermore,
control of the concentration and temperature of the treating liquid
is necessary on each of the treating steps, and, in the phosphating
step, free acid degree, total acid degree and accelerator
concentration in the treating liquid are measured by manual
operation according to a neutralization titration method and the
like, and insufficient ingredients are supplemented appropriately.
Furthermore, as to temperature, there are plural steps where the
treatment is made at 60 to 80.degree. C. and the heating is carried
out with steam piping or the like, and thus a large amount of
energy is used.
[0021] Detailed explanation is made bellow on the latter. When
steel or iron material to be wrought is subjected to phosphating
treatment, the surface of the material is etched in the phosphating
solution and iron ions are eluted into the solution. Transfer of
electrons occurs by this reaction and phosphate salt coating is
formed, but for acceleration of the reaction, it is needed to
deposit and precipitate the iron ions as an insoluble salt. This
insoluble salt is generally called sludge. The sludge needs to be
periodically discharged from the system. Furthermore, water
washings after the pretreatments prior to chemical conversion
coating treatment and after the chemical conversion coating
treatment are contaminated with the treating liquids of the
previous steps, respectively. Since the respective washings contain
various elements, appropriate waste water treatments get necessary.
Usually, these washings as waste water are discharged after
subjection to neutralization treatment, coagulating sedimentation
treatment, etc., but coagulating sedimentation sludge containing
phosphorus, etc. is dumped as industrial wastes as is the case with
the above-mentioned sludge.
[0022] In recent years, reduction of industrial wastes has been
aimed as a large problem for the protection of earthly environment.
Among such activities, chemical conversion coating treatment
forming a lot of industrial wastes as mentioned above is taken up
as one of large problems, and an alternative lubricant and/or an
alternative treating system each forming less industrial wastes
have/has strongly been desired.
[0023] For solving these problems, "a lubricating composition
wherein a water soluble macromolecule or an aqueous emulsion
thereof is used as a base material and a solid lubricant and a
chemical conversion coating forming agent are compounded" etc., are
disclosed in JP 52-20967 A, but coating equal to coating from
chemical conversion coating treatment is not obtained. Also as a
means for solving the above problems, there can, for example, be
mentioned the invention of "an aqueous lubricant for cold plastic
working of metallic material" disclosed in JP 10-8085 A and filed
by the present applicant. The invention relates to an aqueous
lubricant for cold forging working of metal which comprises (A) a
water soluble inorganic salt, (B) a solid lubricant, (C) a at least
one oil ingredient selected from mineral oil, vegetable or animal
oil and synthetic oil, (D) a surfactant and (E) water, and wherein
the solid lubricant and the oil are uniformly dispersed and
emulsified.
[0024] The invention relates to an aqueous non-reactive-type
lubricant, and, therein, it is aimed to shorten the three steps of
phosphating treatment-water washing-reactive-type soap treatment to
one step of lubrication treatment alone. Namely, the aqueous
non-reactive-type lubricant is contacted with a cleaned material to
be wrought by immersion or the like to coat the surface of the
material with the lubricant, and then dried (evaporation of water)
to form lubricating coating on the surface of the material. Such
type of lubricant is called one-step lubricant. However, the
lubricant of the above invention is too unstable to be used
industrially because it emulsifies an oil ingredient, and has not
exerted stable lubricity in cold forging of large working degree or
in tube drawing working where continuous heat load is imposed on
the lubricating coating.
[0025] As a further means for solving the above-mentioned problems,
there can, for example, be mentioned the invention of "a lubricant
composition for plastic working of metallic material" disclosed in
JP 2000-63880 A and made by the present applicant. The invention
relates to a lubricant composition for plastic working of metallic
material which comprises (A) a synthetic resin, (B) a water soluble
inorganic salt and water, and wherein the ratio by mass of (B)/(A)
in terms of solid matter is 0.25/1 to 9/1 and the synthetic resin
is dissolved or dispersed. However even in the invention, stable
lubricity has not been exerted in cold forging of large working
degree or in tube drawing working where continuous heat load is
imposed on the lubricating coating. Furthermore in the invention,
stable lubricity has not been exerted either in the cases where it
is difficult, in actual operation, to apply a lubricant uniformly,
for example in barrel treatment in cold forging, in bundled
treatment in tube reducing working or in coil treatment in wire
drawing working. Although it is indispensable to solve the above
problems in use of a coating-type lubricant, it is a present state
of things that an effective solution has not yet been found.
DISCLOSURE OF INVENTION
[0026] Problem 1
[0027] The present invention is for solving problems which prior
art (particularly prior art on the present invention as a
fundamental invention) has, and aims to provide novel particles, as
an ingredient used mainly in coating-type lubricating coating,
which are excellent in seizure resistance, and can inhibit wear of
tools at the time of plastic working due to a low friction
coefficient of their surfaces, and are slow to cause pollution of
working oil; such particles that, when the particles are
incorporated into a lubricant layer, the lubricant layer can make
itself firmly composite with the carrier layer so that the former
layer may coat the latter layer; powder consisting of the
particles; a suspension containing the particles; processes for
preparing the powder or suspension; and lubricating coating
containing the particles.
[0028] Means for Solving Problem 1
[0029] The present inventors have intensely studied for solving the
above problems (particularly Problem 1). As a result, they found
that particles each of which consists of an inorganic polyvalent
metal compound as a nucleus and a coating of a metallic soap of the
polyvalent metal coating the nucleus, the inorganic polyvalent
metal compound being water sparingly soluble or water insoluble and
having reactivity with an alkali metal salt, ammonium salt or water
soluble ester of a fatty acid; or particles each of which consists
of each of the particles defined above and a coating of an alkali
metal salt, ammonium salt or water soluble ester of a fatty acid
coating the particle, when used mainly as an ingredient in
coating-type lubricating coating, are very suitable as a material
which is excellent in seizure resistance, can inhibit wear of tools
at the time of plastic working due to a low friction coefficient of
their surfaces, and is slow to cause pollution of working oil; and
completed this invention.
[0030] Namely, the invention relates to particles each of which
consists of an inorganic polyvalent metal compound as a nucleus and
a coating of a metallic soap of the polyvalent metal coating the
surface of the nucleus, the inorganic polyvalent metal compound
being water sparingly soluble or water insoluble and having
reactivity with an alkali metal salt, ammonium salt or water
soluble ester of a fatty acid (hereinafter, the above particles are
sometimes referred to as two-layer particles); particles each of
which consists of each of the particles defined above and a coating
of an alkali metal salt, ammonium salt or water soluble ester of a
fatty acid (hereinafter, the "alkali metal salt, ammonium salt or
water soluble ester of a fatty acid" is sometimes referred to as
"alkali soap or the like") coating the surface of the particle
(hereinafter, the above particles are sometimes referred to as
three-layer particles); powder consisting of the particles; a
suspension wherein the above particles are suspended in water or an
aqueous solution of an alkali soap or the like, the average
particle size of particles of the inorganic polyvalent metal
compound being 20 .mu.m or less, the proportion of all the metallic
soap coatings to all the particles being 1 to 30% by mass; a
process for preparing the above powder or suspension; lubricating
coating containing the above particles in an amount of 1% by mass
or more. Hereinafter, the two-layer particles and/or three-layer
particles are sometimes referred to as coated particles.
[0031] Problem 2
[0032] The present invention is also for solving problems which
prior art (particularly prior art on the present invention as a
more practical applied invention) has. Namely, the invention aims
to provide such a lubricating coating forming agent that protection
of earthly environment is taken into consideration; convenient
treatment by a spraying method or immersion method is possible;
chemical conversion coating treatment is unnecessary; and resulting
coating has excellent working performance and excellent seizure
resistance equal to or more than those in chemical conversion
coating treatment method, and, even when uniform application is
difficult as mentioned above, exerts stable lubricating properties
owing to self-repairing effect.
[0033] Means for Solving Problem 2
[0034] The present invention have intensely studied for solving the
above problems (particularly Problem 2), and as a result, they
found that lubricating coating wherein cold forging working of
large working degree is possible and which exerts good lubricity
even in tube drawing working in which continuous heat load is
imposed on the coating, can be obtained by a convenient treating
method of applying, onto a material to be wrought, an aqueous
solution containing particles each of which consists of a
polyvalent metal salt of phosphoric acid as a nucleus and a coating
of a metallic soap of the polyvalent metal coating the surface of
the nucleus, and a water soluble inorganic salt and/or a water
soluble organic acid salt, and drying the resulting wet coating;
and further found that the above-mentioned particles have both
seizure resistance and lubricity, and, therefore, even in a case as
mentioned above where uniform coating is difficult, the particles
are introduced into the tool by melted ingredients in the coating
and exert self-repairing effect on the defect parts of the coating,
and, finally, the coating exerts stable lubricity; and completed
the present invention.
[0035] Namely, the invention relates to a lubricating coating
forming agent wherein particles each of which consists of a water
sparingly soluble or water insoluble polyvalent metal salt of
phosphoric acid (hereinafter merely referred to as polyvalent metal
salt of phosphoric acid) as a nucleus and a coating of a metallic
soap of the polyvalent metal coating the surface of the nucleus
(the particles being hereinafter referred to as particles of coated
polyvalent metal salt of phosphoric acid) are suspended in an
aqueous solution of a water soluble inorganic salt and/or a water
soluble organic acid salt; each of the water soluble inorganic salt
and organic acid salt having a property to form a firm coating when
it is uniformly dissolved in water and the resulting solution is
applied on a metallic material and dried.
[0036] The above particles of coated polyvalent metal salt of
phosphoric acid are included in the above-mentioned "two-layer
particles" in the present invention as a fundamental invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0037] The invention is described in detail below, and, first, the
invention as a fundamental invention is mainly described in detail,
and, then, the invention as a practical applied invention is mainly
described in detail.
[0038] Detailed Description Particularly on the Invention as a
Fundamental Invention
[0039] The inorganic polyvalent metal compound which is used for
preparing the coated particles of the invention, and is water
sparingly soluble or water insoluble and has reactivity with an
alkali soap or the like is an important ingredient as a nucleus
immobilizing the metallic soap layer in the coated particles of the
invention. The inorganic polyvalent metal compound used in the
invention is a granular substance usually supplied as powder or in
a state dispersed in water. The inorganic polyvalent metal compound
is not particularly limited, and includes oxides, hydroxides,
carbonates, phosphates, oxalates, etc. of polyvalent metals, and,
as the polyvalent metal, Zn, Fe, Mn, Ni, Co, Ca, Mg, Ba, Al and Sn
are preferred also in the aspect of the industrial cost, and Zn is
further preferred among them. As preferred specific examples of the
inorganic polyvalent metal compound, there can be mentioned zinc
phosphate, zinc oxide, iron zinc phosphate, iron phosphate (ferrous
phosphate, ferric phosphate), iron oxalate, manganese phosphate,
nickel phosphate, cobalt phosphate, calcium phosphate, calcium
hydrogenphosphate, calcium oxide, calcium hydroxide, etc., and
among them zinc phosphate and zinc oxide are particularly
preferably used.
[0040] The particle size of the inorganic polyvalent metal compound
is preferably as small as possible for making the coated particles
of lubricant use, and, specifically, is preferably 300 .mu.m or
less and more preferably 100 .mu.m or less. As to the lower limit,
there is no particular limitation, but from a limitation on
preparation, the order of 0.3 .mu.m is usually a limit. When it is
intended to obtain the coated particles of the invention in a state
suspended in water, the average particle size of the inorganic
polyvalent metal compound is preferably 20 .mu.m or less, and more
preferably 10 .mu.m or less. When the average particle size is more
than 20 .mu.m, it gets difficult to maintain stably the state
dispersed in water.
[0041] The metallic soap coating the inorganic polyvalent metal
compound in the invention is a salt between the polyvalent metal
and the fatty acid composing the alkali soap or the like, the salt
being formed by reaction of the inorganic polyvalent metal compound
with the alkali soap or the like. As the metallic soap, there can
be mentioned salts between a polyvalent metal such as Zn, Fe, Mn,
Ni, Co, Ca, Al or Sn and a saturated fatty acid or unsaturated
fatty acid having preferably 8 to 22, more preferably 16 to 20
carbon atoms (for example, palmitic acid, stearic acid, eicosanoic
acid, oleic acid, etc.), and zinc stearate is mentioned
representatively.
[0042] From the viewpoint of sufficiently coating the surfaces of
the nuclei, the proportion of the metallic soap coatings to all the
coated particles is preferably 1 to 30% by mass, and more
preferably 2 to 15% by mass.
[0043] The coated particles of the invention also include particles
each of which consists of a particle consisting of two layers of an
inorganic polyvalent metal compound and a metallic soap of the
polyvalent metal coating the metal compound, and a coating of an
alkali soap or the like coating the particle. In the particles
consisting of these three layers, the particles each of which
consists of the inorganic polyvalent metal compound and the
metallic soap of the polyvalent metal coating it may be the same as
those mentioned above. In the three-layer particles, the proportion
of the coatings of the alkali soap or the like to all the particles
is preferably 0.1 to 5% by mass, more preferably 0.1 to 3% by mass
in view of minimizing the amount of water soluble ingredients for
the purpose of heightening the heat resistance of the particles and
maintaining stable lubricating properties.
[0044] In the invention, the alkali soap or the like is not only
needed for preparing the two-layer particles, but itself forms the
outmost layer of the three-layer particles. The alkali soap or the
like used in the invention is an alkali metal salt, ammonium salt
or water soluble ester of a fatty acid. As the fatty acid,
saturated fatty acids or unsaturated fatty acids having 8 to 22,
particularly 16 to 20 carbon atoms are preferred, and there can
specifically mentioned octanoic acid, decanoic acid, lauric acid,
myristic acid, palmitic acid, stearic acid, eicosanoic acid, oleic
acid, etc. As the alkali metal, sodium, potassium and lithium are
preferred. As the water soluble ester, there can be mentioned an
ester obtained by ring-opening polymerizing ethylene oxide to the
carboxyl group of the above fatty acid, etc. As preferred specific
examples of the alkali soap or the like, there can be mentioned a
sodium or potassium salt of palmitic acid, stearic acid or
eicosanoic acid, and most preferred among them is sodium stearate.
Sodium stearate may include both pure one and one containing sodium
salts of other fatty acids. As the latter sodium stearate, sodium
stearate put on the market as C18 soap is mentioned, and its
composition is 95% or more of sodium stearate, less than 3% of
C.sub.16 fatty acids and less than 1% of mixed C.sub.15 and
C.sub.17 fatty acids.
[0045] The present invention also relates to powder consisting of
the above coated particles (namely, the above two-layer particles
or three-layer particles).
[0046] The present invention also relates to a suspension wherein
the above two-layer particles are suspended in water or an aqueous
solution of an alkali soap or the like, the average particle size
of the particles of the inorganic polyvalent metal compound being
20 .mu.m or less. The average particle size of the particles of the
inorganic polyvalent metal compound in the two-layer particles is
preferably 10 .mu.m or less when the average particle size is more
than 20 .mu.m, it gets difficult to maintain the water suspension
state stably. The proportion of metallic soap coatings to all the
two-layer particles in the suspension is preferably 1 to 30% by
mass, more preferably 2 to 15% by mass, as is the case of the
above-mentioned two-layer particles. It is possible to compound
into the suspension a surfactant, a dispersant, a water soluble
resin or the like in view of further heightening the stability of
the dispersoid. The proportion of the two-layer particles to the
whole suspension is not particularly limited so long as stable
suspension of the two-layer particles is maintained, but, usually,
is preferably on the order of 1 to 50% by mass, more preferably on
the order of 5 to 40% by mass.
[0047] Description is made bellow on processes for preparation of
the above powder and suspension of the invention.
[0048] The powder of the invention can be obtained by suspending
particles of the above inorganic polyvalent metal compound in an
aqueous solution of an alkali soap or the like, stirring the
resulting suspension under heating to form metallic soap coating on
the surfaces of the particles of the inorganic polyvalent metal
compound, and drying the suspension.
[0049] As to use amount of the alkali soap or the like to the
inorganic polyvalent metal compound, the alkali soap or the like
may be used so that the above-mentioned proportion of the metallic
soap to the coated particles may be obtained, but, specifically, it
is preferred that the mole ratio of the inorganic polyvalent metal
compound:the alkali soap or the like is the range of 100:0.05 to
100:25. When the amount of the alkali soap or the like is less than
100:0.05, the amount of the metallic soap layer gets extremely
small, and expected effect tends not to be exerted sufficiently.
When the amount of the alkali soap or the like is more than 100:25,
the efficiency of the coating reaction is extremely reduced to
bring about economical disadvantage. When the powder of the
invention is used in lubricant use, the mole ratio of the inorganic
polyvalent metal compound:the alkali soap or the like is preferably
in the range of 100:0.25 to 100:15. When the amount of the alkali
soap or the like is less than 100:0.25, sufficient lubrication
performance tends hard to obtain, and it is more than 100:15, such
problems tend to occur that the foaming properties of the
suspension gets high due to existence of a lot of unreacted alkali
soap or the like, and so on.
[0050] For accelerating reaction in preparation of the powder, it
is preferred to adjust the temperature of the suspension to
60.degree. C. or more, particularly 70 to 100.degree. C., and the
pH to 9 or more, particularly 10 to 12. As to the mechanism of the
reaction, it is presumed that, on particles of the inorganic
polyvalent metal compound, double decomposition reaction between
the inorganic polyvalent metal compound and the alkali soap or the
like takes place, and metallic soap layers coat the particles of
the inorganic polyvalent metal compound as nuclei. For making the
pH the above-mentioned alkali side, there can be used hydroxides
(sodium hydroxide, potassium hydroxide, etc.), carbonates (sodium
carbonate, potassium carbonate, etc.), bicarbonates (sodium
bicarbonate, potassium bicarbonate, etc.) of alkali metal, aqueous
ammonia, etc., and preferred among them is sodium hydroxide. After
surfaces of the particles of the inorganic polyvalent metal
compound are coated with a preferred amount of metallic soap
coatings, the suspension is dried into powder, and the method of
the drying may be a conventional one. For example, a method of
filtering the suspension and drying the resulting solid, a method
of spray drying the suspension, or the like can be adopted.
[0051] Powder obtained by the above-mentioned process for preparing
the powder of the invention is, usually, powder of three-layer
particles consisting of the inorganic polyvalent metal compound,
the metallic soap and the alkali soap or the like. Powder of
two-layer particles consisting of the inorganic polyvalent metal
compound and the metallic soap can be prepared by washing away the
alkali soap or the like composing the outermost layer of the
three-layer particles obtained in a way as mentioned above, with
hot water, aqueous alcohol solution or the like.
[0052] The suspension of the invention can be obtained by
suspending particles of the inorganic polyvalent metal compound in
an aqueous solution of an alkali soap or the like, and stirring the
suspension under heating to form metallic soap coating on the
surfaces of the particles of the inorganic polyvalent metal
compound. In this case, for suspending the particles of the
inorganic polyvalent metal compound stably, the particle size of
the particles of the inorganic polyvalent metal compound needs to
be adjusted to 20 .mu.m or less, and is preferably adjusted to 10
.mu.m or less. For further stabilizing the suspension state, it is
possible to compound a surfactant, a dispersant, a water soluble
resin or the like.
[0053] The use amount of the alkali soap or the like to the
inorganic polyvalent metal compound, the temperature and pH of the
suspension for accelerating the reaction, and additives for making
the pH the above-mentioned alkaline side may be the same as in the
case of the preparation of the powder of the invention.
[0054] The powder and suspension relating to the metallic soap of
the invention exert excellent performance as lubricants used in the
cold plastic working field, etc. Namely, coating formed by making
the powder or suspension of the invention adhering to the surface
of a material to be subjected to cold plastic working shows
excellent performance as lubricating coating for cold plastic
working. When the powder of suspension is used for forming
lubricating coating, the powder or suspension alone can be made
into coating, but it can also be made into coating together with
other general ingredients such as lubricating waxes, solid
lubricants, extremely pressure additives, coating forming resins
and/or viscosity adjusting agents. For example, by using the powder
or suspension together with a lubricating oil containing a mineral
oil or palm oil as a main ingredient, or a olefin wax or high
molecular wax which melts and is liquidized at the time of working,
it is possible to give the latter (i.e., the lubricating oil, etc.)
excellent seizure resistance.
[0055] When the powder or suspension of the invention is compounded
into a lubricating coating to give it seizure resistance, the
compounding is preferably made so that the content of the powder or
the solid matter in the suspension in the resulting coating may be
1% by mass or more, particularly 5% by mass or more. When the
compounding proportion of the powder or the solid matter in the
suspension is less than 1% by mass, it is impossible to give the
lubricating coating sufficient seizure resistance. Although the
conditions for the adhesion are not particularly limited, the dry
coating thickness of the lubricating coating is preferably made to
be in the range of 0.5 to 50 .mu.m, more preferably made to be in
the range of 1.0 to 30 .mu.m. When the coating thickness is less
than 0.5 .mu.m, there is an anxiety that, especially in the strong
working field, sufficient seizure resistance cannot be obtained to
cause poor working. Further, the coating thickness of more than 50
.mu.m is superfluous and only increases the amount of the coating
peeling away at introduction into the tool, and, thus, tends to
bring about economical disadvantage.
[0056] A method for forming, on the surface of a material to be
wrought, lubricating coating containing the powder or solid matter
in the suspension of the invention is not particularly limited, and
a conventional method can be adopted. For example, in the case of
the aqueous suspension, lubricating coating can be obtained by
making the aqueous suspension adhere onto the surface of the
material by immersion treatment, spraying, roll coater treatment or
the like, and then drying the resulting wet coating by natural
seasoning, compulsory hot air drying or the like. In this
operation, it is possible to mix a resin, an inorganic salt or the
like for heightening the adhesion of the powder or the solid matter
in the suspension, or an oil, a soap, a metallic soap, a wax or the
like for supplementing the lubricity of powder or the solid matter
in the suspension.
[0057] Further, as to a method for forming coating solely from the
powder in a dry state, the powder of the invention can be made to
adhere by a powder box method, an electrostatic coating method or
the like, and an electrostatic coating method is particularly
preferred because control of adhesion properties and adhesion
amount is easy and stable and uniform lubricating coating can be
obtained. It is also possible to mix a resin ingredient or wax
ingredient having a low melting point, when the powder is made to
adhere, for preventing peeling of the powder from the surface of
the material to be wrought, and then heat the material to be
wrought to immobilize the powder. It is also possible to mix powder
of soap, metallic soap, wax, resin or the like for supplement of
lubricity. Further, it is possible to obtain lubricating coating of
a continuous coating state, through working heat and pressure, by,
after making the powder of the invention adhere, subjecting the
material to be wrought to light plastic working of the order of
skin pass; and the operation is preferred since the resulting
coating is coating further excellent in lubrication performance and
barrier performance such as corrosion resistance. Particularly,
lubricating coating obtained by a combination of electrostatic
coating method and light plastic working of the order of skin pass
is equal to "coating of phosphating treatment plus soap treatment"
in all performance aspects. In this occasion, coating obtained
after mixing the powder with a high molecular synthetic wax in a
ratio by mass of preferably 1:9 to 9:1, more preferably 1:1 to 9:1
is excellent in lubricity, oil resistance, etc.
[0058] Detailed Description Particularly on the Invention as a More
Practical Applied Invention
[0059] The invention is described in detail below. The particles of
the invention each of which consists of a polyvalent metal salt of
phosphoric acid as a nucleus and a metallic soap of the polyvalent
metal coating the nucleus, namely particles of coated polyvalent
metal salt of phosphoric acid give the resulting coating heat
resistance and lubricity. It is necessary for a polyvalent metal
salt of phosphoric acid to be selected to be sparingly soluble or
insoluble in water. As preferred examples of the polyvalent metal
in the polyvalent metal salt of phosphoric acid, there can be
mentioned Zn, Fe, Mn, Ni, Co, Ca, Mg, Ba, Al and Sn, and further
preferred among them are Zn, Fe and Ca. As specific examples of the
polyvalent metal salt of phosphoric acid, there can be mentioned
zinc phosphate, iron zinc phosphate, iron phosphate (ferrous
phosphate, ferric phosphate), manganese phosphate, nickel
phosphate, cobalt phosphate, calcium phosphate, calcium
hydrogenphosphate, magnesium phosphate, magnesium
hydrogenphosphate, barium phosphate, barium hydrogenphosphate,
aluminum phosphate, tin phosphate, etc., and preferred among them
are zinc phosphate, iron zinc phosphate, iron phosphate (ferrous
phosphate, ferric phosphate), calcium phosphate and calcium
hydrogenphosphate. These can be used alone or in combination of two
or more.
[0060] The particles of the coated polyvalent metal salt of
phosphoric acid exist in coating obtained by applying the
lubricating coating forming agent of the invention onto a metallic
material to be subjected to cold plastic working, and give the
metallic material seizure resistance and lubricity; and, after
being introduced into a die by melted coating ingredients at the
time of working, exert an action to repair coating defects, namely
a self-repairing action. For these purposes, in a state suspended
in water or an aqueous solution of an alkali soap or the like, the
average particle size of the particles of the coated polyvalent
metal salt of phosphoric acid is preferably 30 .mu.m or less, more
preferably 0.3 to 30 .mu.m and still more preferably 0.5 to 20
.mu.m. The average particle size of the polyvalent metal salt of
phosphoric acid in the particles of the coated polyvalent metal
salt of phosphoric acid is preferably 20 .mu.m or less, more
preferably 0.2 to 20 .mu.m and still more preferably 0.4 to 10
.mu.m. Furthermore, for giving sufficient lubricity, the proportion
by mass of the metallic soap coatings to all the particles of the
coated polyvalent metal salt of phosphoric acid is preferably 1 to
30%, more preferably 2 to 15%.
[0061] The particles of the coated polyvalent metal salt of
phosphoric acid are included in "two-layer particles" in the
present invention particularly as a fundamental invention, and can
be prepared in a similar way as in the two-layer particles.
[0062] Next, the water soluble inorganic salt needs to have not
only a property to give the lubricating coating hardness but also a
property to immobilize the particles of the coated polyvalent metal
salt of phosphoric acid in the coating. A water soluble inorganic
salt selected therefor needs to have a property to dissolve in
water uniformly and, when the solution is applied onto a metallic
material and dried, form firm coating. It is preferred to use, as
the water soluble inorganic salt having such properties, at least
one selected from the group consisting of alkali metal salts of
sulfuric acid, alkali metal salts of silicic acid and alkali metal
salts of boric acid. As specific examples thereof, there can be
mentioned sodium sulfate, potassium sulfate, sodium silicate,
potassium silicate, sodium borate, potassium borate, etc., and
these can be used alone or in combination of two or more.
[0063] The water soluble organic acid salt needs to have a property
not only to give hardness to the lubricating coating, but to
immobilize the particles of the coated polyvalent metal salt of
phosphoric acid in the coating. A water soluble organic acid salt
selected therefor needs to have a property to dissolve in water
uniformly and, when the solution is applied onto a metallic
material and dried, form firm coating. It is preferred to use, as
the water soluble organic acid salt having such properties, at
least one selected from the group consisting of alkali metal salts
of malic acid, alkali metal salts of succinic acid, alkali metal
salts of citric acid and alkali metal salts of tartaric acid. As
more specific examples thereof, there can be mentioned sodium
malate, potassium malate, sodium succinate, potassium succinate,
sodium citrate, potassium citrate, sodium tartrate, potassium
tartrate, etc.
[0064] The compounding proportion between the particles of the
coated polyvalent metal salt of phosphoric acid (A) and the total
of the water soluble inorganic salt and the water soluble organic
acid salt (B) as a ratio by mass in solid matter of (B)/(A) is
preferably 0.01 to 20.0, more preferably 0.01 to 16.0 and still
more preferably 0.01 to 7.5. At less than 0.01, the particles of
the coated polyvalent metal salt of phosphoric acid are not
immobilized in the coating, the water soluble inorganic salt of the
lubricating coating is not drawn into the tool against shear onto
the coating at the time of working, and seizure resistance gets
insufficient. On the other hand, at more than 20.0, since a
probability that the water soluble inorganic salt having a high
friction coefficient exists on the coating surface gets extremely
high, the friction coefficient of the coating gets high, the
coating gets easy to break and seizure gets liable to occur.
[0065] The lubricating coating forming agent of the invention may
contain a smectite clay mineral according to necessity, and it is
usually preferred to incorporate it. The smectite clay mineral used
in the invention is a clay mineral having the following general
formula. ("Clay Handbook 2nd edition" edited by Japan Clay Society
and published by Gihodo Publishing CO., Ltd., pages 58-66, 1987 ):
X.sub.m(Y.sup.2+,
Y.sup.3+).sub.2-3Z.sub.4O.sub.10(OH).sub.2.nH.sub.2O wherein X is
at least one of K, Na, 1/2 Ca and 1/2 Mg, m is 0.25 to 0.6,
Y.sup.2+ is at least one of Mg.sup.2+, Fe.sup.2+, Mn.sup.2+,
Ni.sup.2+, Zn.sup.2+ and Li.sup.+, Y.sup.3+ is at least one of
Al.sup.3+, Fe.sup.3+, Mn.sup.3+ and Cr.sup.3+, Z is at least one of
Si and Al, and nH.sub.2O is water among layers. Y.sup.2+, Y.sup.3+
in (Y.sup.2+, Y.sup.3+) means Y.sup.2+ and/or Y.sup.3+. Further, in
the above, X represents a cation among the layers, Y is a cation of
the octahedron and Z is a cation of the tetrahedron.
[0066] The smectite clay mineral used in the invention needs to
have a property to give dispersion stability in liquid to the
particles of the coated polyvalent metal salt of phosphoric acid
and stabilize distribution of the particles in the coating.
Therefor, formation of stable sol in an aqueous phase and increase
of viscosity accompanying sharp increase of the concentrations of
the contained ingredients get necessary. Smectite clay minerals
generally show the above-mentioned properties when dispersed in an
aqueous phase, and as smectite clay minerals having such
properties, it is preferred to use at least one selected from the
group consisting of hectorite, montmorillonite, beidellite,
nontronite, saponite, iron saponite, stevensite and sauconite.
Smectite clay minerals can be obtained not only as natural
resources but as synthetic ones, and both can be used in the
invention.
[0067] The compounding proportion of the smectite clay mineral as s
a ratio by mass in terms of solid matter of (C)/(A) wherein (A) are
the particles of the coated polyvalent metal salt of phosphoric
acid and (C) is the smectite clay mineral is preferably 0.005 to
0.5, more preferably 0.01 to 0.4. At less than 0.005, an effect to
improve the dispersion stability of the particles of the coated
polyvalent metal salt of phosphoric acid in the liquid and an
effect to stabilize the distribution in the coating are not
sufficient, and at more than 0.5, the lubricating coating forming
agent gets a paste state to make its stable use difficult.
[0068] The lubricating coating forming agent of the invention may
contain an auxiliary lubricant according to necessity, and,
usually, it is preferred to incorporate it in the agent. The
auxiliary lubricant needs to have an action to lower the friction
coefficient of lubricating coating formed by the lubricating
coating forming agent of the invention, and, as a melt carrier
introducing the particles of the coated polyvalent metal salt of
phosphoric acid between the material to be wrought and the tool,
help the self-repairing effect of the coating. Therefor, the
auxiliary lubricant, as one which melts with heat generated at the
time of plastic working to give the coating slipping properties and
acts as a melt carrier, is preferably at least one selected from
the group consisting of oil, soap, metallic soap, wax and
polytetrafluoroethylene. As the oil, there can be used vegetable
oils, synthetic oils, mineral oils, etc., and there can, for
example, be mentioned palm oil, castor oil, rapeseed oil, machine
oil, turbine oil, spindle oil, ester oil, silicone oil, etc. The
soap is an alkali metal salt of a fatty acid, and there can, for
example, be mentioned sodium salts, potassium salts, etc. of
saturated or unsatureated fatty acids having 8 to 22 carbon atoms
such as octanoic acid, decanoic acid, lauric acid, myristic acid,
palmitic acid, stearic acid, eicosanoic acid and oleic acid. As the
metallic soap, there can be mentioned salts of polyvalent metals
such as calcium, zinc, magnesium and barium with the
above-mentioned fatty acids. As the wax, there can be mentioned
polyethylene wax, polypropylene wax, carnauba wax, paraffin wax,
etc. As the polytetrafluoroethylene, there can be mentioned
polytetrafluoroethylene having a molecular weight of the order of
1,000,000 to 10,000,000. It is preferred that such an auxiliary
lubricant is incorporated in the lubricating coating forming agent
by mixing it in the form of aqueous emulsion or aqueous dispersion
with other ingredients. The auxiliary lubricant is usually
dispersed or emulsified in the lubricating coating forming agent of
the invention.
[0069] The compounding proportion of the auxiliary lubricant as s a
ratio by mass in terms of solid matter of (D)/(A) wherein (A) are
the particles of the coated polyvalent metal salt of phosphoric
acid and (D) is the auxiliary lubricant is preferably 0.03 to 18.0,
more preferably 0.05 to 15.0 and still more preferably 0.5 to 5.0.
At less than 0.03, the friction coefficient of the lubricating
coating is increased and the effect to act as a melt carrier is not
sufficient, and at more than 18.0, the coating is softened, and the
coating tends to be broken because it gets incapable of
withstanding shearing force thereon at the time of working.
[0070] The lubricating coating forming agent of the invention may
contain an organic high molecular compound according to necessity.
It is preferred that the organic high molecular compound is water
soluble or water dispersible and has a weight average molecular
weight of 1,000 to 1,000,000. The organic high molecular compound
needs to have an action to give coating strength to lubricating
coating formed using the lubricating coating forming agent. The
organic high molecular compound is not particularly limited so long
as it has coating formability, and there can, for example, be
mentioned resin as a polymer of ethylenically unsaturated
monomer(s) (particularly, acrylic resin), urethane resin, epoxy
resin, phenol resin, hydroxymethylcellulose,
carboxymethylcellulose, etc. It is preferred that such an organic
high molecular compound is incorporated in the lubricating coating
forming agent by mixing it in the form of aqueous emulsion or
aqueous dispersion with other ingredients. In view of improving the
coating strength of coating formed by the lubricating coating
forming agent, the organic high molecular compound is added into
the lubricating coating forming agent so that its content can be
preferably 0.5 to 25% by mass, more preferably 1.0 to 15% by mass
based on the whole solid matter including itself.
[0071] In plastic working wherein the working is severe, it is
possible to further incorporate a solid lubricant in the
lubricating coating forming agent. As the solid lubricant in such a
case, one existing stably in the coating and capable of assisting
lubrication at a high load is preferred. As such solid lubricants,
there can be mentioned graphite, molybdenum disulfide, boron
nitride, fluorinated graphite, mica, etc.
[0072] In plastic working wherein the working is severer, it is
possible to incorporate an extremely pressure additive in the
lubricating coating forming agent. As the extremely pressure
additive in such a case, one existing stably in the coating and
capable of exerting extreme-pressure effect at the contact surface
between the tool and the metal is preferred. As such extremely
pressure additives, there can be mentioned sulfur containing
extremely pressure additives, organomolybdenum extremely pressure
additives, phosphorus containing extremely pressure additives and
chlorine containing extremely pressure additives such as sulfurized
olefins, sulfurized esters, sulfites, thiocarbonates, chlorinated
fatty acids, phosphoric esters, phosphorous esters, molybdenum
dithiocarbamate (MoDTC), molybdenum dithiophophate (MoDTP) and zinc
dithiophosphate (ZnDTP).
[0073] When a dispersant is necessary to disperse or emulsify the
particles of the coated polyvalent metal salt of phosphoric acid,
the auxiliary lubricant, and/or the solid lubricant and/or
extremely pressure additives, as such a dispersant, there can be
used a dispersant selected from nonionic surfactants, anionic
surfactants, amphoteric surfactants, cationic surfactants, water
soluble high molecular dispersants and so on.
[0074] There is no particular limitation on a process for preparing
the lubricating coating forming agent of the invention so long as a
lubricating coating forming agent prepared meets the
above-mentioned conditions. For example, the agent can be obtained
by adding particles of a coated polyvalent metal salt of phosphoric
acid, and, as optional ingredients, a smectite clay mineral, an
auxiliary lubricant, and/or a solid lubricant and/or an extremely
pressure additive, if necessary after being made into a dispersion
or emulsion using a dispersant and water, into an aqueous solution
of a water soluble inorganic salt and/or a water soluble organic
acid salt; and then stirring the resulting mixture. The solid
matter concentration of the lubricating coating forming agent is
not particularly limited so long as the lubricating coating forming
agent prepared meets the above-mentioned conditions, but, in view
of handling properties and stability of the lubricating coating
forming agent, the solid matter concentration is preferably 1 to
80% by mass, more preferably 10 to 60% by mass.
[0075] The lubricating coating forming agent of the invention can
be used as a lubricant used when a metallic material such as iron
or steel, stainless steel, plated steel (for example, steel
subjected to plating treatment such as electrogalvanizing, molten
zinc plating, aluminum zinc plating, aluminum plating or iron zinc
plating), aluminum or aluminum alloy, magnesium alloy, tin or tin
alloy, titanium or titanium alloy, or copper or copper alloy is
subjected to cold plastic working such as forging, wire drawing,
tube reducing or sheet forming. There is no particular limitation
on the shape of the metallic material.
[0076] For exerting good lubricity, it is preferred, prior to
applying the lubricating coating forming agent of the invention, to
pretreat a metallic material to be worked in order of cleaning
(usually, an alkali cleaner is used), water washing, descaling
(shot blasting or acid washing with hydrochloric acid or the like)
and water washing to clean the surface of the metallic material.
When oxidation scale does not adhere or the metallic material is
used in a use where oxidation scale is needed, descaling and
succeeding water washing can be omitted. These pretreatments can be
carried out by conventional ways.
[0077] The lubricating coating forming agent of the invention is
applied to the surface of a metallic material by a conventional
method such as immersion, spraying or . The application is carried
out until the metal surface is sufficiently coated with the
lubricating coating forming agent, and there is no particular
limitation on time of the application. After the application, the
lubricating coating forming agent needs to be dried. The drying may
be made by allowing the coating to stand at ordinary temperature,
but, usually, is preferably made at 60 to 150.degree. C. for 10 to
60 minutes. In view of preventing seizure, the coating mass of the
lubricating coating forming agent is preferably 1 g/m.sup.2 or
more, more preferably 3 to 30 g/m.sup.2.
[0078] Lubricating coating obtained from the lubricating coating
forming agent of the invention shows stable cold plastic working
performance because the particles of the coated polyvalent metal
salt of phosphoric acid having good seizure resistance and slipping
properties are uniformly held in the coating by immobilizing effect
of the water soluble inorganic salt and/or the water soluble
organic acid salt, and the smectite clay mineral. Furthermore,
since, because the auxiliary lubricant ingredient melting by heat
generation due to working acts as a melt carrier, and so on, the
particles of the coated polyvalent metal salt of phosphoric acid
are drawn into the die and exert a self-repairing action on coating
defect parts, the lubricating coating shows stable lubricity, even
in tube drawing working such as tube reducing or wire drawing
wherein lubricating coating forming treatment is, usually, carried
out in such a state such as a banded state or a coiled state that
the resulting coating is liable to be ununiform.
EXAMPLES
[0079] The present invention is further specifically described
below together with its effects, by giving examples of the
invention together with comparative examples.
I. Examples and Comparative Examples on the Invention as a
Fundamental Invention
[0080] 1. Preparation of Suspension and Powder of Metallic
Soap-Coated Particles
[0081] A suspension and powder of metallic soap-coated particles
were prepared according to the processes shown below. For
confirming that coated particles, wherein nuclei of the inorganic
polyvalent metal compound are coated with coatings of the metallic
soap, are prepared, soap ingredients in the powder prepared or soap
ingredients in the powder obtained by drying the suspension
prepared were separated into alkali soap or the like dissolving in
an aqueous ethanol solution and metallic soap not dissolving
therein, and the mass of each was measured, whereby formation of
metallic soap was confirmed. The above method is explained in more
detail below. One gram of a powder sample was stirred in aqueous
50% ethanol solution for 4 hours, and the mixture was filtered with
filter paper. Then, the filtrate and the residue were heated in 1N
hydrochloric acid, respectively, to decompose the soap ingredients
into fatty acid(s). Each of the mixtures was extracted with diethyl
ether, and the proportion of metallic soap formation=([(fatty
acid(s) from the metallic soap)/(fatty acid(s) from the alkali soap
or the like+fatty acid(s) from the metallic soap)].times.100) was
calculated. When the proportion of metallic soap formation is 50%
or more, it was judged that the nuclei surfaces were coated with a
sufficient amount of metallic soap layers.
[0082] (A1)
[0083] Ten grams of sodium stearate and 1 g of sodium hydroxide
were mixed with 100 g of particles of zinc phosphate having an
average particle size of 1 .mu.m and dispersed in 1 L of water, and
the mixture was stirred at a liquid temperature of 90 to 95.degree.
C. for 30 minutes to obtain a suspension of metallic soap-coated
particles.
[0084] Proportion of metallic soap formation=82% (this value
corresponds to about 8% as the proportion by mass of metallic soap
coatings based on all the two-layer particles)
[0085] (A2)
[0086] Two hundred grams of zinc phosphate powder, 30 g of
potassium stearate and 1 g of potassium hydroxide were dispersed
into 700 mL of water under stirring, and the mixture was stirred at
a liquid temperature of 70.degree. C. for 1 hour. Solid matter was
recovered by filtration, and stirred for 4 hours in aqueous 50%
ethanol solution, and, by second filtration, solid matter was
obtained. This was dried in an oven of 100.degree. C. to obtain dry
powder of metallic soap-coated particles containing no layer of the
alkali soap.
[0087] Proportion of metallic soap formation=78% (this value
corresponds to about 10% as the proportion by mass of metallic soap
coatings based on all the two-layer particles)
[0088] (A3)
[0089] Two hundred grams of zinc oxide, 10 g of sodium stearate and
3 g of sodium hydroxide were dispersed into 700 mL of water under
stirring, and the mixture was stirred at a liquid temperature of
90.degree. C. for 20 minutes. Then, solid matter was recovered by
filtration and dried in an oven of 100.degree. C. to obtain dry
powder of metallic soap-coated particles.
[0090] Proportion of metallic soap formation=53% (this value
corresponds to about 3% as the proportion by mass of metallic soap
coatings based on all the three-layer particles)
[0091] 2. Test on Resistance to Oil Pollution
[0092] As one of the problems which the powder of the metallic
soap-coated particles of the invention aims to solve, there is
resistance to pollution of oil. This aims to solve a pollution
phenomenon of working oil which metallic soap has as a drawback, by
using the above powder for lubricant use in place of conventional
metallic soap. A test method and evaluation criterion therefor are
given below. One gram of one of the prepared powders of metallic
soap-coated particles or 1 g of one of metallic soap powders on the
market shown below was added to 100 g of former oil on the market,
and the mixture was left alone in a stirring state at 60.degree. C.
Then, the stirring was stopped, and, under a suspension state of
the oil at 1 hour after, resistance to oil pollution was evaluated.
The sooner the suspended matter can be precipitated, the
better.
[0093] Evaluation criterion: A: the suspended matter is completely
precipitated, and the transparent layer occupies 95% or more of the
whole volume. B: the suspended matter is precipitated, and the
transparent layer of less than 95% of the whole volume can be
recognized. C: the oil is in a suspension state, and no transparent
layer can be recognized.
[0094] Evaluation results of the test on resistance to oil
pollution on Examples I-1 and I-2 of the invention and Comparative
examples I-1 and I-2 are shown in Table 1. The powders of metallic
soap-coated particles of the invention mentioned in the examples
were very excellent in resistance to oil pollution. The reason is
presumed to be that the metallic soap layers are immobilized on the
surfaces of the particles of the inorganic polyvalent metal
compound, and thus it gets hard for the metallic soap layers to
peel off into the oil. On the other hand, calcium stearate powder
(B3) and zinc stearate powder (B6) of the comparative examples are
metallic soap powders having no nucleus, and, thus, got to be in a
swollen state in the oil, and continued to be suspended in the oil
by being finely dispersed.
1 TABLE 1 Results of resistance to Sample powder oil pollution
Example I-1 A2 A Example I-1 A3 A Com. exam. I-1 B3 C Com. exam.
I-2 B6 C Note: Com. exam.: Comparative example
[0095] 3. Evaluation as Lubricating Coating Forming Material
[0096] The compositions of the lubricating coatings of Examples I-3
to I-9 obtained by using, as lubricating coating forming materials,
the suspension of the metallic soap-coated particles of the
invention prepared in the above or the powders of the metallic
soap-coated particles of the invention prepared in the above, and
the compositions of the lubricating coatings of Comparative
examples I-3 to I-7 not using suspension of metallic soap-coated
particles nor powder of metallic soap-coated particles of the
present invention are shown in Table 2.
[0097] 3.1. Lubricating Coating Forming Material
[0098] Lubricating coating forming materials used in the present
test are shown below.
[0099] (A1) The suspension of the metallic soap-coated particles of
the invention obtained in the above
[0100] (A2) The powder of the metallic soap-coated particles of the
invention obtained in the above
[0101] (A3) The powder of the metallic soap-coated particles of the
invention obtained in the above
[0102] (A4) Aqueous suspension of zinc phosphate particles having
an average particle size of 0.5 .mu.m
[0103] (A5) Zinc oxide powder having an average particle size of 50
.mu.m
[0104] (B1) Water-dispersed polyethylene wax
[0105] (B2) Water-dispersed olefin wax
[0106] (B3) Calcium stearate powder
[0107] (B4) Montanic acid wax powder
[0108] (B5) Oxidized polyethylene wax powder
[0109] (B6) Zinc stearate powder
[0110] (C1) Sodium polyacrylate (molecular weight 10,000)
[0111] (C2) Aqueous emulsion of urethane resin (polyester urethane
resin)
[0112] 3.2. Treating Method
[0113] For forming lubricating coating of an example of the
invention or a comparative example on the surface of a test
material, one of the following treating methods was used.
[0114] (a) Immersion Treatment Method
[0115] A test piece whose surface was cleaned was immersed in
lubricating coating forming suspension of ordinary temperature to
make the suspension adhere thereon, and was subjected to drying in
a hot air drying furnace of 100.degree. C. to form lubricating
coating on the surface of the test piece. The amount of the dry
coating adhering was about 15 g/m.sup.2.
[0116] (b) Electrostatic Coating Method
[0117] A test piece whose surface was cleaned was electrostatically
coated with lubricating coating forming powder to form lubricating
coating in a powder adhesion state on the surface of the test
piece. As an electrostatic powdering apparatus, GX300 made by Nihon
Parkerizing Co., Ltd was used, and the lubricating coating forming
powder was charged at a voltage of 60 kV. Adhesion of the charged
lubricating coating forming powder on the surface of the test piece
by an electrostatic coating method was carried out using an
electrostatic coating gun GX116 made by Nihon Parkerizing Co., Ltd.
Air pressures for supply of the powder in this operation were 98
kPa as the main air pressure and 196 kPa as the sub-air pressure.
The coating time was 1 second, and the amount of the powder coating
adhering was about 15 g/m.sup.2.
[0118] 3.3. Test Method and Evaluation Criterion
[0119] 3.3.1. Spike Test
[0120] Spike test working was made according to the method
disclosed in JP 5-7969 A, and lubricity was evaluated by the spike
height of the test piece after the working. The higher the spike
height is, the better the lubricity is.
[0121] Test piece: A material used for the test was annealed S45C
material which was made spherical and commercially available, and
the shape of the test piece was 25 mm .phi. in diameter and 30 mm
in height.
[0122] Evaluation criterion: A: Spike height was 13 mm or more
[0123] B: Spike height was 12 mm or more but less than 13 mm
[0124] C: Spike height was less than 12 mm
[0125] D: The material was seized onto the die, resulting in
molding being impossible
[0126] 3.3.2. Drawing Test
[0127] Steel wire as a test piece coated with a lubricating coating
was subjected to drawing working of the order of skin pass (first
drawing: reduction in area being 10.3%), and, then, subjected to
drawing working of reduction in area being 31.5% (second drawing),
using a draw bench drawing testing machine on the market.
[0128] Test piece: A material used for the test was SCr440 material
on the market, and the shape of the test piece was 9.5 mm .phi. in
diameter and 1 m in length.
[0129] Evaluation Criterion:
[0130] A: Seizure and flaws were not found up to the second
drawing
[0131] B: Seizure was not found up to the second drawing, but some
flaws were found.
[0132] C: Seizure and flaws were not found up to the first drawing,
but seizure occurred at the second drawing resulting in drawing
being impossible
[0133] D: Seizure occurred at the first drawing resulting in
drawing being impossible
2 TABLE 2 Composition of lubricating film Seizure Lubricant Other
resisting ingredient ingredient ingredient (com- (com- (compounding
pounding pounding Treating amount %) amount %) amount %) method
Example I-3 A1 (100) -- -- a I-4 A1 (50) B1 (45) C1 (5) a I-5 A1
(20) B2 (70) C2 (10) a I-6 A2 (100) -- -- b I-7 A2 (80) B4 (20) --
b I-8 A3 (50) B5 (50) -- b I-9 A3 (30) B4 (60) C1 (10) b Com. exam
I-3 A4 (100) -- -- a I-4 A4 (50) B1 (45) C1 (5) a I-5 A5 (100) --
-- b I-6 A5 (50) B3 (50) -- b I-7 A5 (30) B5 (70) -- b Note: The
compounding amount of each ingredient is compounding amount as
solid matter Com. exam.: Comparative example
[0134]
3 TABLE 3 Results of evaluation as lubricating film forming
material Spike test Drawing test Example I-3 B B I-4 A A I-5 A A
I-6 B B I-7 A A I-8 B B I-9 A B Com. exam. I-3 D D I-4 C C I-5 D D
I-6 C D I-7 C C Note: Com. exam.: Comparative example
[0135] As shown in the above results of evaluation (see Table 3),
each of the lubricating coatings of Examples I-3 to I-9 obtained by
using the metallic soap compositions of the invention which play a
role of seizure resisting ingredient and, at the same time, also
have lubricating performance, showed good lubricating performance.
On the other hand, in Comparative examples I-3 to I-7, because of
exposure of the seizure resisting ingredient having high friction
coefficient, the resulting lubricating coatings could not exert
sufficient performance as lubricating coating being subjected to
strong working, and, moreover, load to the tool is judged to be
high.
[0136] As apparent from the above explanation, the coated particles
of the invention consisting of an inorganic polyvalent metal
compound as a nucleus, and metallic soap coating or metallic soap
coating plus coating of alkali soap or the like on it coating the
nucleus, are mainly used as ingredients for coating type
lubricating coating, and are suitable as materials which are
excellent in seizure resistance, and, because of their low surface
friction coefficient, can inhibit wear of tools at the time of
plastic working, and do not easily cause pollution of working oil.
Therefore, the industrial utility value of the present invention is
extremely great.
II. Examples and Comparative Examples on the Invention as a
Particularly Practical Applied Invention
Examples II-1 to II-12 and Comparative examples II-1 to II-9
[0137] Lubricating coating forming agents of ingredients and their
compositions shown in Table 4 were prepared.
[0138] <Coating of Polyvalent Metal Salt of Phosphoric Acid with
Metallic Soap>
[0139] As to Examples II-1 to II-12 and Comparative examples II-1,
II-2, II-5 and II-6, coating of a polyvalent metal salt of
phosphoric acid [ingredient (A)] with metallic soap was carried out
(Table 4). Specifically, 90 g of a polyvalent metal salt of
phosphoric acid having an average particle size of 1 to 5 .mu.m
dispersed in 1L of water, 9 g of sodium stearate and 1 g of
potassium hydroxide were mixed and stirred at a liquid temperature
of 80 to 85.degree. C. for 30 minutes to obtain a suspension of
particles of coated polyvalent metal salt of phosphoric acid.
[0140] <Preparation of the Lubricating Coating Forming Agent of
Example II-1>
[0141] Preparation of a lubricating coating forming agent was made
so that the respective ingredients got to be the ratios of Table 4.
The procedure of the preparation is as follows. First, the water
soluble inorganic salt was dissolved in water, and then the
smectite clay mineral was incorporated in the solution and
uniformly dispersed. Thereafter, the above suspension of particles
of coated polyvalent metal salt of phosphoric acid was incorporated
in the suspension, and then the auxiliary lubricant was added, and
the mixture was stirred to prepare the lubricating coating forming
agent of Example II-1. As to starting materials used in Example
II-1, the polyvalent metal salt of phosphoric acid is zinc
phosphate (solid), the water soluble inorganic salt is aqueous 50%
by mass sodium silicate dispersion, and the smectite clay mineral
is montmorillonite (solid).
[0142] The lubricating coating forming agents of Examples II-2 to
II-12 and Comparative examples II-1 to II-7 were prepared in the
similar manner as above. The lubricating coating forming agents of
Comparative example II-8 is an existing coating-type lubricating
coating forming agent, and the lubricating coating forming agent of
Comparative example II-9 is a phosphate salt plus soap treating
agent on the market.
[0143] <Test Piece>
[0144] The following test pieces were used for the following
evaluations.
[0145] Friction coefficient measuring test: SPCC-SB 150 mm.times.70
mm.times.0.8 mmt (t is thickness)
[0146] Evaluation of forging properties: S45C annealed material
which was made spherical 30 mm.phi..times.18 to 40 mm
[0147] Tube reducing properties: STKM17A 25.4 mm.phi..times.2.5
mmt.times.2,000 mm
[0148] Wire drawing properties: S45C annealed material 3.0
mm.phi..times.50,000 mm
[0149] <Coating Forming Treatment>
[0150] coating forming treatment was made according to the
following steps.
[0151] In the cases of Examples II-1 to II-12 and Comparative
example II-1 to II-8
[0152] (1) Cleaning: a degreasing agent on the market (registered
trademark Fine Cleaner 4360, made by Nihon Parkerizing Co., Ltd.),
concentration 20 g/L, temperature 60.degree. C., immersion 10
minutes
[0153] (2) Water washing: tap water, room temperature, immersion 30
seconds
[0154] (3) Descaling: hydrochloric acid washing, concentration
17.5%, room temperature, immersion 10 minutes
[0155] (4) Water washing: tap water, room temperature, immersion 30
seconds
[0156] (5) Treatment: treating agent of an example or comparative
example, room temperature, immersion 10 seconds, targeted adhesion
amount 5 g/m.sup.2
[0157] (6) Drying: 80.degree. C., 5 minutes
[0158] In the case of Comparative example II-9
[0159] (1) Cleaning: a degreasing agent on the market (registered
trademark Fine Cleaner 4360, made by Nihon Parkerizing Co., Ltd.),
concentration 20 g/L, temperature 60.degree. C., immersion 10
minutes
[0160] (2) Water washing: tap water, room temperature, immersion 30
seconds
[0161] (3) Descaling: hydrochloric acid washing, concentration
17.5%, room temperature, immersion 10 minutes
[0162] (4) Water washing: tap water, room temperature, immersion 30
seconds
[0163] (5) Chemical conversion coating treatment: Zinc phosphate
chemical conversion coating agent on the market (registered
trademark Palbond 181X, made by Nihon Parkerizing Co., Ltd.),
concentration 90 g/L, temperature 80.degree. C., immersion 10
minutes
[0164] (6) Water washing: tap water, room temperature, immersion 30
seconds
[0165] (7) Soap treatment: reactive soap lubricant on the market
(registered trademark Palube 235, made by Nihon Parkerizing Co.,
Ltd.), concentration 70 g/L, temperature 80.degree. C., immersion 5
minutes
[0166] (8) Drying: 80.degree. C., 3 minutes
[0167] <Coating Performance Evaluation Test>
[0168] A friction coefficient measurement test was made, after the
above coating forming treatment, according to a Bowden test which
is the most standard friction coefficient measurement test. Since,
in the Bowden test, there is a stable stage of friction coefficient
after initial sliding, the friction coefficient at the stable stage
was regarded as the friction coefficient of the lubricating
coating. Measurement conditions in the test are as follows.
[0169] Sliding type: reciprocating sliding type
[0170] Steel sphere: 10 mm.phi.SUJ2 steel sphere
[0171] Vertical load: 50N
[0172] Sliding velocity: 10 mm/s
[0173] Temperature: 60.degree. C.
[0174] Sliding number of times: 200 times
[0175] A forging test was made by a backward piercing test. The
backward piercing test is such a test that cylindrical test pieces
are subjected to backward piercing working wherein punches are
knocked into the test pieces, the heights of the test pieces are
varied from 18 mm up to 40 mm by every 2 millimeters, and possible
working degree is determined. When seizure resistance is
insufficient, flaws due to seizure are formed on the internal
surfaces of the test pieces and on the punches. These flaws were
checked by visual observation, and the highest height of the test
pieces where no flaw is formed was evaluated as showing the
lubricity of a lubricating coating forming agent. The treatment was
carried out both by a method of treating test pieces separately one
by one (one piece treatment) and by a method of treating plural
pieces together in a rotary barrel (barrel treatment). Evaluation
criterion is shown below. A and B are practical levels.
[0176] A: The workable height of the test piece is 40 mm or
more.
[0177] B: The workable height of the test piece is 36 mm or more,
but less than 40 mm.
[0178] C: The workable height of the test piece is 32 mm or more,
but less than 36 mm.
[0179] D: The workable height of the test piece is less than 32
mm.
[0180] A tube reducing test was made by carrying out tube reducing
working under the following conditions and making evaluation by
such limiting reduction in area that no seizure was formed. The
limiting reduction in area was assumed to be such reduction in area
that three pipes were subjected to the tube reducing working and
all the three pipes could be worked. The treatment was carried out
both by a method of treating pipes separately one by one (one pipe
treatment) and by a method of treating three pipes in a bundled
state (bundle treatment). Evaluation criterion is shown below. A
and B are practical levels.
[0181] Die: R die
[0182] Plug: cylindrical plug
[0183] Tube reducing velocity: 15 m/min.
[0184] A: The limiting reduction in area is 50% or more.
[0185] B: The limiting reduction in area is 43% or more, but less
than 50%.
[0186] C: The limiting reduction in area is 38% or more, but less
than 43%.
[0187] D: The limiting reduction in area is less than 38%.
[0188] A wire drawing test was made by carrying out wire drawing
working under the following conditions and making evaluation by
such limiting wire drawing velocity that stable wire drawing was
possible. The coating treatment was carried out both by a method of
extremely loosing the bundled state of the wire rod coil so that
the wire rods could not contact mutually (a method of stretching
the coil into a spring state; one rod treatment) and by a method of
treating the wire rod coil in a bundled state so as to promote
contact among the wire rods (bundled treatment). Evaluation
criterion is shown below. A and B are practical levels.
[0189] Die: R die; 2.75 mm .phi.
[0190] Reduction in area: 15.0%
[0191] Wire drawing velocity: 10 to 100 m/min.
[0192] A: Limiting wire drawing velocity is 100 m/min or more.
[0193] B: Limiting wire drawing velocity is 80 m/min or more, but
less than 100 m/min.
[0194] C: Limiting wire drawing velocity is 60 m/min or more, but
less than 80 m/min.
[0195] D: Limiting wire drawing velocity is less than 60 m/min.
[0196] <Test Results>
[0197] Results of the above tests are shown in Table 5. As apparent
from Table 5, the lubricating coating forming agents of the
invention in Examples II-1 to II-12 showed good lubricity
irrespective of working forms, and also showed stable lubricity
even in the cases of barrel treatment and bundled treatment where
uniform treatment was difficult. On the other hand, the lubricating
coating forming agents of Comparative examples II-1 and II-2 which
contain metallic soap-coated particles but no water soluble
inorganic salt nor water soluble organic acid salt showed only low
lubricity even when they were applied uniformly. Further, in
Comparative examples II-3 and II-4 where the surfaces of particles
of the polyvalent metal salt of phosphoric acid were not coated
with metallic soap, since the friction coefficients of the
particles were high and the self-repairing effect of the resulting
coatings was not exerted, lubricity was not stable in the barrel
treatment and the bundled treatment. The lubricating coating
forming agents of Comparative examples II-5 and II-6 where calcium
hydroxide or iron oxalate poor in solubility in water was used in
place of a water soluble inorganic salt or a water soluble organic
acid salt could not form continuous coating, and the resulting
coatings are low in lubricity. In Comparative examples II-7 and
II-8 where particles of a coated polyvalent metal salt of
phosphoric acid are not contained, since the self-repairing effect
of the resulting coatings was not exerted, lubricity was not stable
in the barrel treatment and the bundled treatment. In the
phosphating treatment plus soap treatment of Comparative example
II-9, stable lubricity was exerted irrespective of treating
methods, but loads to the environment are large in view of
treatment of industrial wastes and waste water, control of treating
liquids, high energy consumption by high temperature treatment, and
so on. Thus, the lubricating coating forming agent of the
invention, because of containing particles of a coated polyvalent
metal salt of phosphoric acid and a water soluble inorganic salt,
can prevent lowering of lubricity owing to ununiform coating which
was the most difficult problem of coating-type lubricating coating
forming agent, and can realize stable lubricity.
4TABLE 4 Examples II-1 to II-12 and Comparative examples II-1 to
II-9 Ingredient*1 Ratio by mass as solid matter (A) (B) (C) (D)
(B)/(A) (C)/(A) (D)/(A) Example (II) 1 zinc phosphate sodium
silicate*2 montmorillonite -- 10.0 0.01 -- 2 zinc phosphate
potassium silicate*3 hectorite paraffin wax 2.0 0.05 1.5 3 zinc
phosphate potassium tetraborate -- polyethylene wax 0.02 -- 15.0 4
zinc iron phosphate sodium silicate*2 hectorite sodium stearate 0.5
0.25 0.5 5 zinc iron phosphate sodium citrate -- machine oil 0.01
0.005 1.0 6 zinc iron phosphate sodium sulfate nontronite -- 1.0
0.5 -- 7 iron phosphate sodium silicate + -- palm oil 16.0 -- 2.0
potassium sulfate*4 8 iron phosphate sodium tetraborate hectorite
paraffin wax 0.5 0.01 0.5 9 iron phosphate potassium sulfate +
sauconite paraffin wax 3.5 0.05 2.0 potassium silicate*5 10 calcium
phosphate sodium silicate*2 nontronite -- 10.0 0.3 -- 11 calcium
phosphate potassium sulfate + -- polyethylene wax 15.0 -- 0.05
potassium silicate*4 12 calcium phosphate sodium sulfate hectorite
palm oil 7.5 0.4 2.0 Comparative 1 zinc phosphate -- -- calcium
stearate -- 0.2 2.5 example (II) 2 zinc iron phosphate --
nontronite polyethylene wax -- 0.1 12.0 3 zinc phosphate*6 sodium
silicate*2 nontronite -- 0.1 0.05 -- 4 calcium phosphate*6 sodium
tetraborate -- palm oil 5.0 -- 5.0 5 iron phosphate calcium
hydroxide -- paraffin wax 2.0 -- 2.5 6 zinc iron phosphate iron
oxalate -- polyethylene wax 1.0 -- 0.5 7 -- potassium silicate*7 --
graphite*8 *9 8 Existing coating-type lubricating film forming
agent Proportion of ingredient as solid matter*10 (B) (D) (E) 35%
50% 15% 9 Phosphate salt treatment + soap treatment Adhesion mass
(g/m.sup.2) phosphate metallic unreacted salt soap soap 6.7 2.3 3.2
Notes of Table 4 *1 As to ingredients, (A) is a polyvalent metal
salt of phosphoric acid, (B) is a water soluble inorganic salt or
water soluble organic acid salt, (C) is a smectite clay mineral,
and (D) is an auxiliary lubricant. *2 SiO.sub.2:Na.sub.2O = 2:1 *3
SiO.sub.2:K.sub.2O = 3:1 *4 Sodium sulfate:sodium metasilicate =
7:3 *5 Sodium sulfate:potassium silicate (SiO.sub.2:K.sub.2O = 3:1)
= 7:3 *6 Zinc phosphate and calcium phosphate whose surfaces are
not coated with coating of metallic soap of these polyvalent metals
were used. *7 SiO.sub.2:K.sub.2O = 4:1 *8 In place of an auxiliary
lubricant, graphite was used as a solid lubricant. *9 Comparative
example 7 was carried out using potassium silicate
(SiO.sub.2:K.sub.2O = 4:1): graphite = 6:4. *10 In Comparative
example 8, Ingredient B is sodium tetraborate, Ingredient D is
calcium stearate, and Ingredient E is urethane resin (made by
Dai-ichi Kogyo Seiyaku Co., Ltd.; Superflex 110). *11 Furthermore,
as Ingredient (E), a phenol resin (made by Gunei Kagaku Co., Ltd.;
Resitop PL-6020) was used in Example 9, and an urethane resin (made
by Dai-ichi Kogyo Seiyaku Co., Ltd.; Superflex 110) in Example 12.
The # phenol resin and the urethane resin were used in amounts of
7.0% by mass and 8.5% by mass, respectively, based on the total of
Ingredients (A) to (E), in terms of solid matter.
[0198]
5TABLE 5 Results of evaluation (Examples II-1 to II-12 and
Comparative examples II-1 to II-9 Results of evaluation Forging
Tube reducing Wire drawing Friction properties properties
properties Load to coefficient one barrel one bandled one bandled
environment Example (II) 1 0.07 A A B B B B .largecircle. 2 0.06 A
A A A A A .largecircle. 3 0.05 A B B B B B .largecircle. 4 0.06 A A
A A A A .largecircle. 5 0.05 B B B B B B .largecircle. 6 0.07 B B B
B B B .largecircle. 7 0.07 A B A B A B .largecircle. 8 0.06 A A A A
A A .largecircle. 9 0.06 A A A A A A .largecircle. 10 0.07 B B B B
B B .largecircle. 11 0.06 A B A B A B .largecircle. 12 0.06 A A A A
A A .largecircle. Comparative 1 0.06 C D C D B D .largecircle.
examples (II) 2 0.05 C C C C B B .largecircle. 3 0.10 D D D D D D
.largecircle. 4 0.08 B C B D B C .largecircle. 5 0.08 B D B D B C
.largecircle. 6 0.06 B D B D B C .largecircle. 7 0.07 C D C D C C
.largecircle. 8 0.07 B D B D B C .largecircle. 9 0.06 B B A A A A
X
[0199] Lubricating coatings obtained by applying the lubricating
coating forming agent of the invention onto the surfaces of various
metallic materials give the metallic materials excellent cold
plastic working properties, namely excellent lubricity and
excellent seizure resistance. Particularly, the lubricating coating
forming agent of the invention can give metallic materials
excellent working performance even in barrel treatment and bundled
treatment where it has been difficult for conventional coating-type
lubricating coating forming agent to give stable working
performance.
* * * * *