U.S. patent application number 11/531786 was filed with the patent office on 2007-01-18 for environmentally pollution-free anti-corrosion pigment composition.
This patent application is currently assigned to DAI NIPPON TORYO CO., LTD.. Invention is credited to Takashi MATSUDA, Osamu OGAWA, Toru TAKI.
Application Number | 20070012220 11/531786 |
Document ID | / |
Family ID | 34994127 |
Filed Date | 2007-01-18 |
United States Patent
Application |
20070012220 |
Kind Code |
A1 |
MATSUDA; Takashi ; et
al. |
January 18, 2007 |
Environmentally Pollution-Free Anti-Corrosion Pigment
Composition
Abstract
The present invention provides an environmentally
pollution-free, anti-corrosive pigment composition which is free of
any heavy metal such as lead and/or chromium, which is free of zinc
and/or water-soluble ions and which is excellent in the
anti-corrosive effect. The anti-corrosive pigment composition
comprises condensed calcium phosphate prepared by firing a mixture
which comprises a calcium-containing component and a
phosphorus-containing component and in which the molar ratio
(Ca/P=m) of calcium to phosphorus present in these components falls
within the following range: 0.50<m<1.00, at a temperature
ranging from 180 to 350.degree. C.
Inventors: |
MATSUDA; Takashi; (Tochigi,
JP) ; OGAWA; Osamu; (Tochigi, JP) ; TAKI;
Toru; (Tochigi, JP) |
Correspondence
Address: |
NORRIS, MCLAUGHLIN & MARCUS, P.A.
875 THIRD AVE
18TH FLOOR
NEW YORK
NY
10022
US
|
Assignee: |
DAI NIPPON TORYO CO., LTD.
1-124, Nishikujo 6-chome, Konohana-ku, Osaka-shi
Osaka
JP
|
Family ID: |
34994127 |
Appl. No.: |
11/531786 |
Filed: |
September 14, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP02/05594 |
Mar 18, 2005 |
|
|
|
11531786 |
Sep 14, 2006 |
|
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Current U.S.
Class: |
106/462 ;
106/470; 106/471; 252/387; 423/305; 423/306 |
Current CPC
Class: |
C09D 5/084 20130101;
C09D 17/004 20130101 |
Class at
Publication: |
106/462 ;
106/471; 106/470; 423/305; 423/306; 252/387 |
International
Class: |
C01B 15/16 20060101
C01B015/16; C01B 25/26 20060101 C01B025/26 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 18, 2004 |
JP |
2004 078019 |
Claims
1. An environmentally pollution-free, anti-corrosive pigment
composition free of any heavy metal, characterized in that it
comprises condensed calcium phosphate prepared by firing a mixture
which comprises a calcium-containing component and a
phosphorus-containing component and in which the molar ratio
(Ca/P=m) of calcium to phosphorus present in these components falls
within the following range: 0.50<m<1.00, at a temperature
ranging from 180 to 350.degree. C.
2. The environmentally pollution-free, anti-corrosive pigment
composition as set forth in claim 1, wherein the condensed calcium
phosphate is a compound represented by the following general
formula (1): Ca.sub.xH.sub.y(P.sub.nO.sub.3n+1).sub.z (1) wherein,
x represents a real number ranging from 1 to 4, y represents a real
number ranging from 0 to 2, z represents a real number ranging from
1 to 2 and n is an integer ranging from 2 to 6, provided that these
symbols should satisfy the following relation: 2x+y=(n+2)z.
3. The environmentally pollution-free, anti-corrosive pigment
composition as set forth in claim 1, wherein the molar ratio
(Ca/P=m) falls within the following range: 0.60<m<0.80.
4. The environmentally pollution-free, anti-corrosive pigment
composition as set forth in claim 1, wherein the condensed calcium
phosphate is selected from the group consisting of
CaH.sub.2P.sub.2O.sub.7, Ca.sub.2P.sub.2O.sub.7,
Ca.sub.3H.sub.2(P.sub.2O.sub.7).sub.2,
Ca.sub.4H.sub.2(P.sub.3O.sub.10).sub.2, Ca.sub.4P.sub.6O.sub.19 and
a mixture thereof.
5. The environmentally pollution-free, anti-corrosive pigment
composition as set forth in claim 1, wherein the calcium-containing
component is selected from the group consisting of elemental
calcium, calcium oxide, calcium hydroxide, calcium carbonate,
calcium monohydrogen phosphate, calcium dihydrogen phosphate,
tricalcium phosphate, calcium pyrophosphate and calcium dihydrogen
pyrophosphate.
6. The environmentally pollution-free, anti-corrosive pigment
composition as set forth in claim 1, wherein the
phosphorus-containing component is selected from the group
consisting of phosphoric acid, polyphosphoric acid, phosphorous
acid and diphosphorus pentaoxide.
7. The environmentally pollution-free, anti-corrosive pigment
composition as set forth in claim 1, wherein the mixture is fired
at a temperature ranging from 200 to 290.degree. C.
8. The environmentally pollution-free, anti-corrosive pigment
composition as set forth in claim 1, wherein it further comprises
an alkaline earth metal compound.
9. The environmentally pollution-free, anti-corrosive pigment
composition as set forth in claim 8, wherein the alkaline earth
metal compound is selected from the group consisting of oxides,
hydroxides, silicates, carbonates and mixtures of calcium,
magnesium and strontium.
10. The environmentally pollution-free, anti-corrosive pigment
composition as set forth in claim 8, wherein the alkaline earth
metal compound is incorporated into the environmentally
pollution-free anti-corrosive pigment composition in an amount
ranging from 0.1 to 60% by mass on the basis of the total mass of
the pigment composition.
11. The environmentally pollution-free, anti-corrosive pigment
composition as set forth in claim 1, wherein it further comprises a
chelated compound selected from the group consisting of organic
phosphonic acids, carboxylic acids each possessing a chelating
ability and neutralized salts thereof.
12. The environmentally pollution-free, anti-corrosive pigment
composition as set forth in claim 11, wherein the organic
phosphonic acid is selected from the group consisting of
nitrilo-trimethylene phosphonic acid, nitrilo-triethylene
phosphonic acid, nitrilo-tripropylene phosphonic acid,
nitrilo-tris-diethyl methylene phosphonic acid,
ethylenediamine-tetramethylene phosphonic acid,
ethylenediamine-tetra-ethylene phosphonic acid,
ethylenediamine-tetra-propylene phosphonic acid,
methane-1-hydroxy-1,1-diphosphonic acid,
ethane-1-hydroxy-1,1-diphosphonic acid,
propane-1-hydroxy-1,1-diphosphonic acid and 2-hydroxy
phosphono-acetic acid.
13. The environmentally pollution-free, anti-corrosive pigment
composition as set forth in claim 11, wherein the organic
carboxylic acid is selected from the group consisting of citric
acid, malic acid, oxalic acid, malonic acid, succinic acid,
itaconic acid, maleic acid, glycolic acid, thio-glycolic acid,
salicylic acid, sulfo-salicylic acid, anthranilic acid,
N-methyl-anthranilic acid, 3-amino-2- naphthoic acid,
1-amino-2-naphthoic acid, 2-amino-1-naphthoic acid,
1-amino-anthraquinone-2-carboxylic acid, tannic acid and gallic
acid.
14. The environmentally pollution-free, anti-corrosive pigment
composition as set forth in claim 11, wherein the neutralized salt
is selected from the group consisting of alkali metal salts,
alkaline earth metal salts, aluminum salts and ammonium salts of
the foregoing organic phosphonic acids and organic carboxylic
acids.
15. The environmentally pollution-free, anti-corrosive pigment
composition as set forth in claim 1, wherein the condensed calcium
phosphate is surface-treated.
16. An environmentally pollution-free, anti-corrosive paint
composition characterized in that it comprises the environmentally
pollution-free, anti-corrosive pigment composition as set forth in
claim 1.
Description
TECHNICAL FIELD
[0001] The present invention relates to an anti-corrosive pigment
composition which can be incorporated into, for instance,
anti-corrosive paints and, more particularly, to an environmentally
pollution-free anti-corrosive pigment composition which is free of
any heavy metal such as lead, chromium and/or zinc, which can be
applied to, for instance, a variety of anti-corrosive paints and
anti-corrosive oils, which has a wide variety of applications and
which is excellent in the anti-corrosive effect.
BACKGROUND ARTS
[0002] Until now, as anti-corrosive pigments, there have widely
been used lead-containing anti-corrosive pigments such as red lead,
lead cyanamide and lead suboxide; and chromate-containing
anti-corrosive pigments such as zinc chromate and strontium
chromate.
[0003] These lead-containing and chromate-containing anti-corrosive
pigments have excellent anti-corrosive characteristics, but the use
thereof has gradually been regulated while taking into
consideration, for instance, safety, hygiene, and environmental
pollution. More specifically, it is apprehended that they may hurt
the human health.
[0004] On the other hand, there have likewise been proposed
phosphoric acid salt-containing pigments, molybdate-containing
pigments, organic phosphonic acid salt-containing pigments and
borate-containing pigments as environmentally pollution-free
anti-corrosive pigments.
[0005] These environmentally pollution-free anti-corrosive pigments
are much less problem concerning the safety and hygiene, but the
anti-corrosive properties thereof are in general inferior to those
observed for the lead-containing and chromate-containing
anti-corrosive pigments. Furthermore, these environmentally
pollution-free pigments cause various problems, for example, in
that they require a high production cost and further they are
deteriorated in their physical properties, dispersibility and
storage stability.
[0006] These environmentally pollution-free pigments in general
comprise, as the principal components, solid acids easily dissolved
out and accordingly, they likewise comprise, as secondary
components, solid base components in order to control any excess
dissolution of such acidic components and to maintain the pH value
of the resulting coated film at the neutral level. For this reason,
most of the environmentally pollution-free pigments currently put
on the market comprise zinc oxide as such a solid base
component.
[0007] Nevertheless, it has been considered questionable whether
zinc-containing compounds, in particular, zinc oxide used as a
pigment component is safe or not mainly in the United States and
Europe, along with the recent intensified regulation of the
environmental pollution. This is because, it has been proved that
zinc oxide may adversely affect the oceanic life or the marine
animals and accordingly, there have been such a tendency to start
self-controlling of the use of zinc oxide in the coating or
painting of, for instance, containers for transporting foods, not
to mention the use thereof in the places where it may have a bad
influence.
[0008] In addition, when incorporating such a zinc oxide-containing
anti-corrosive pigment into an oily vehicle such as boiled oil or
an oily varnish, the zinc oxide reacts with the vehicle to thus
cause a phenomenon or cohesion of pigment components called
"seeding" and this in turn becomes a cause of a problem such as the
development of insufficient appearance of the resulting coated film
and the reduction of the physical properties of the same, as has
been described in JIS K5621. Moreover, the coated film containing
such a zinc oxide-containing anti-corrosive pigment causes a
problem in that it is liable to develop white rust on a zinc-plated
plate.
[0009] Thus, there have been developed environmentally
pollution-free, anti-corrosive pigments, which do not contain zinc
oxide at all (see, for instance, Japanese Un-Examined Patent
Publication (hereunder referred to as "J.P. KOKAI") Nos. Hei
8-283619, Hei 11-049979 and 2003-113482).
[0010] However, these environmentally pollution-free,
anti-corrosive pigments are still insufficient in both
anti-corrosive properties and wide-spread applicability.
[0011] For instance, J.P. KOKAI 2003-113482 proposes a method for
preparing an anti-corrosive pigment composition starting from
precipitates obtained through a reaction of sodium tripolyphosphate
with a water-soluble alkaline earth metal compound under wet
conditions. However, the anti-corrosive pigment composition thus
prepared never ensures the desired long-lasting anti-corrosive
properties since it comprises a large amount of water-soluble ions
such as Na.sup.+, NO.sub.3.sup.- and Cl.sup.-.
DISCLOSURE OF THE INVENTION
[0012] The present invention has been developed while taking into
consideration the foregoing existing condition of the
environmentally pollution-free, anti-corrosive pigment composition
and accordingly, it is an object of the present invention to
provide an environmentally pollution-free anti-corrosive pigment
composition which is free of any heavy metal such as lead and/or
chromium, which is likewise free of zinc and/or water-soluble ions
and which is excellent in the anti-corrosive effect.
[0013] The inventors of this invention have conducted various
studies to achieve the foregoing object of the present invention,
have found that the foregoing object can be accomplished by
providing a pigment composition having the following constitution
and have thus completed the present invention.
[0014] According to the present invention, there is thus provided
an environmentally pollution-free, anti-corrosive pigment
composition free of any heavy metal, characterized in that it
comprises the condensed calcium phosphate prepared by firing a
mixture which comprises a calcium-containing component and a
phosphorus-containing component and in which the molar ratio
(Ca/P=m) of calcium to phosphorus present in these components falls
within the following range: 0.50<m<1.00, at a temperature
ranging from 180 to 350.degree. C.
EFFECTS OF THE INVENTION
[0015] The environmentally pollution-free, anti-corrosive pigment
composition according to the present invention is free of any
environmental pollution since it never comprises any harmful heavy
metal element such as lead and/or chromium as well as zinc and thus
shows an excellent anti-corrosive effect. This anti-corrosive
pigment composition can be incorporated into various kinds of
resin-containing paints and therefore, it is quite useful as a
pigment used in anti-corrosive paints for a variety of metal
materials.
[0016] Further, the anti-corrosive pigment composition of the
present invention can be used according to the methods identical to
those applied to other anti-corrosive materials or in various
applications similar to those for the anti-corrosive pigments, for
instance, the composition of the present invention can be added to
anti-corrosive oils and the composition can likewise be used in the
method of using the same as an inhibitor.
MODE FOR CARRYING OUT THE INVENTION
[0017] The present invention will hereunder be described in more
detail.
[0018] The detailed mechanism of the anti-corrosive action of the
condensed calcium phosphate as a component of the anti-corrosive
pigment composition of the present invention has not yet been
clearly elucidated, but it would be considered that the condensed
calcium phosphate is slightly dissolved in water under a corrosive
atmosphere and it has thus a quite strong ability of chelating
metals and it can form a passive film on an iron surface to thus
prevent the generation of any rust.
[0019] It is essential that the condensed calcium phosphate used in
the present invention is a mixture which comprises a
calcium-containing component and a phosphorus-containing component
and in which the molar ratio (Ca/P=m) of calcium to phosphorus
present in these components falls within the following range:
0.50<m<1.00 and preferably, it is desirable to use such a
mixture whose molar ratio m of calcium to phosphorus present in the
mixture desirably falls within the range: 0.60<m<0.80.
[0020] This is because, if the molar ratio of calcium to phosphorus
present in the mixture (Ca/P=m) falls within the range:
m.ltoreq.0.50, an excess of the condensed phosphate ions is
dissolved out, the resulting coated film in turn undergoes
blistering and results in the reduction of the anti-corrosive
effect. On the other hand, if the molar ratio m falls within the
range: m.gtoreq.1.00, the amount of the condensed phosphate ions
dissolves out, which is required for the formation of a passive
film, is too low and it would be difficult to form condensed
calcium phosphate.
[0021] The condensed calcium phosphate used in the present
invention is desirably a compound represented by the following
general formula (1): Ca.sub.xH.sub.y(P.sub.nO.sub.3n+1).sub.z (1)
[0022] wherein, x represents a real number ranging from 1 to 4, y
represents a real number ranging from 0 to 2, z represents a real
number ranging from 1 to 2 and n is an integer ranging from 2 to 6,
provided that these symbols should satisfy the following relation:
2x+y=(n+2)z.
[0023] In this respect, however, the condensed calcium phosphate
represented by Formula (1) may include compounds each having an
arbitrary number of water of crystallization.
[0024] Typical examples of the condensed calcium phosphate
represented by Formula (1) include CaH.sub.2P.sub.2O.sub.7,
Ca.sub.2P.sub.2O.sub.7, Ca.sub.3H.sub.2(P.sub.2O.sub.7).sub.2,
Ca.sub.4H.sub.2(P.sub.3O.sub.10).sub.2, and
Ca.sub.4P.sub.6O.sub.19, which may desirably be used alone or in
the form of a mixture thereof.
[0025] The condensed calcium phosphate represented by Formula (1)
may principally be analyzed according to the X-ray diffractometry
and can be identified by the determination of, for instance, peaks
obtained by an X-ray diffraction device.
[0026] The condensed calcium phosphate used in the present
invention may be in a single crystalline state or a mixture of
various kinds of crystalline states (including amorphous
state).
[0027] The condensed calcium phosphate serving as a constituent of
the anti-corrosive pigment composition of the present invention is
desirably prepared by firing a mixture of the foregoing
calcium-containing component and phosphorus-containing component at
a temperature ranging from 180 to 350.degree. C. and preferably 200
to 290.degree. C. If the firing temperature is less than
180.degree. C., phosphoric acid never undergoes any condensation
and accordingly, any condensed calcium phosphate cannot be
prepared. On the other hand, if the firing temperature exceeds
350.degree. C., most part of the resulting condensed calcium
phosphate is converted into calcium metaphosphate
[Ca(PO.sub.3).sub.2] and therefore, the resulting product is not
condensed calcium phosphate having a desired anti-corrosive
effect.
[0028] The time required for firing the mixture of the foregoing
calcium-containing component and phosphorus-containing component is
not restricted to any particular range, but it preferably falls
within the range of from 1 to 30 hours. In addition, the condensed
calcium phosphate obtained after the firing may optionally be
subjected to a post-treatment such as pulverization and/or
classification depending on, for instance, particular
applications.
[0029] Examples of the phosphorus-containing components preferably
used herein are ortho-phosphoric acid, polyphosphoric acid,
phosphorous acid, diphosphorus pentaoxide. Moreover, examples of
the calcium-containing components preferably used herein are
elemental calcium, calcium oxide, calcium hydroxide, calcium
carbonate, calcium mono-hydrogen phosphate, calcium dihydrogen
phosphate, tricalcium phosphate, calcium pyrophosphate, and calcium
dihydrogen pyrophosphate. In this connection, when using calcium
nitrate, calcium acetate and calcium chloride as such
calcium-containing components, there is such a tendency that
water-soluble calcium ions remain in the resulting fired product
and the resulting anti-corrosive pigment composition has an
impaired anti-corrosive effect.
[0030] Subsequently, the inventors of this invention have searched
for the solid base to be combined with the condensed calcium
phosphate for the development of an environmentally pollution-free
anti-corrosive pigment which is also free of any zinc component and
have found that certain alkaline earth metal compounds show an
excellent effect of improving the anti-corrosive properties of the
resulting pigment composition. Specific examples of such alkaline
earth metal compounds are, for instance, oxides, hydroxides,
silicates and carbonates of, for instance, calcium, magnesium and
strontium. All of these compounds ensure excellent anti-corrosive
properties, but it is desirable to use, in particular, magnesium
compounds.
[0031] The amount of the alkaline earth metal compound to be
incorporated into the environmentally pollution-free anti-corrosive
pigment composition ranges from 0 to 90% by mass and more
preferably 0.1 to 60% by mass on the basis of the total mass of the
pigment composition. In this case, the amount of the condensed
calcium phosphate accordingly ranges from 10 to 100% by mass and
more preferably 40 to 99.9% by mass on the basis of the total mass
of the pigment composition. In particular, when using strongly
basic oxides or hydroxides as such alkaline earth metal compounds,
the amount of the compound to be incorporated into the
environmentally pollution-free anti-corrosive pigment composition
desirably ranges from 0.5 to 20% by mass on the basis of the total
mass of the pigment composition. In this respect, these alkaline
earth metal compounds may be used, in the present composition,
alone or in any combination of at least two of them.
[0032] If the rate of the condensed calcium phosphate incorporated
into the composition is lower than the lower limit specified above,
the amount of the condensed phosphate ions dissolved out is
reduced, which serves as a principal factor of the composition for
the development of the desired anti-corrosive effect and
accordingly, the resulting pigment composition possesses an
insufficient anti-corrosive effect, while, when the rate thereof
exceeds the upper limit specified above, the acidic properties of
the condensed calcium phosphate in its solid state cannot be
neutralized because of the corresponding reduction of the amount of
the alkaline earth metal compound and consequently, the
anti-corrosive effect originated from the condensed calcium
phosphate is liable to be reduced.
[0033] The alkaline earth metal compound can be used after mixing
the same with the condensed calcium phosphate or after further
firing the mixture.
[0034] The environmentally pollution-free anti-corrosive pigment
composition according to the present invention, which comprises the
foregoing condensed calcium phosphate alone or a mixture of the
condensed calcium phosphate with the foregoing alkaline earth metal
compound, may further comprise a silicon-containing compound as an
optional component. The incorporation of such a silicon-containing
compound into the pigment composition would permit the fixation of
any product formed through the corrosion of a basis metallic
material and thus the use thereof is quite favorable for the
improvement of the desired anti-corrosive effect. The
silicon-containing compound is not restricted to any specific one
and usable herein in general include, for instance, colloidal
silica, silica products prepared according to the wet methods and
the vapor phase processes, or naturally occurring minerals
containing silica in the form of silicon dioxide. The amount of the
silicon atom-containing compound to be incorporated into the
environmentally pollution-free anti-corrosive pigment composition
in general ranges from 0 to 80% by mass and preferably 0.5 to 50%
by mass on the basis of the total mass of the pigment
composition.
[0035] The environmentally pollution-free anti-corrosive pigment
composition according to the present invention, which comprises the
condensed calcium phosphate alone or a mixture of the condensed
calcium phosphate with the alkaline earth metal compound, may show
a satisfactory anti-corrosive effect, but the anti-corrosive effect
of the pigment composition would further be improved when
incorporating, into the composition, an organic phosphonic acid or
carboxylic acid possessing a chelating ability and/or a neutralized
salt thereof (a chelated compound), because of the synergistic
effect of these components.
[0036] Examples of organic phosphonic acids having a chelating
ability and used in the environmentally pollution-free
anti-corrosive pigment composition according to the present
invention are amino-alkylene phosphonic acids such as
nitrilo-tri-methylene phosphonic acid, nitrilo-triethylene
phosphonic acid, nitrilo-tri-propylene phosphonic acid and
nitrilo-tris-diethyl methylene phosphonic acid;
ethylenediamine-tetra-alkylene phosphonic acids such as
ethylenediamine-tetra-methylene phosphonic acid,
ethylenediamine-tetra-ethylene phosphonic acid and
ethylenediamine-tetra-propylene phosphonic acid;
alkylmethane-1-hydroxy-1,1-di-phosphonic acids such as
methane-1-hydroxy-1,1-diphosphonic acid,
ethane-1-hydroxy-1,1-diphosphonic acid and
propane-1-hydroxy-1,1-diphosphonic acid; and 2-hydroxy
phosphono-acetic acid. In addition, examples of carboxylic acid
possessing a chelating ability are organic carboxylic acids such as
citric acid, malic acid, oxalic acid, malonic acid, succinic acid,
itaconic acid, maleic acid, glycolic acid, thio-glycolic acid,
salicylic acid, sulfo-salicylic acid, anthranilic acid,
N-methyl-anthranilic acid, 3-amino-2-naphthoic acid,
1-amino-2-naphthoic acid, 2-amino-1-naphthoic acid,
1-aminoanthraquinone-2-carboxylic acid, tannic acid and gallic
acid.
[0037] Moreover, examples of neutralized salts of these carboxylic
acids are carboxylic acids partially or completely neutralized
with, for instance, the alkali metals of the foregoing compounds,
alkaline earth metals, aluminum and ammonium ions (including
primary, secondary, tertiary and quaternary ammonium ions replaced
with substituents on the nitrogen atom).
[0038] In this respect, the amount of the organic phosphonic acid
or carboxylic acid possessing a chelating ability and/or a
neutralized salt thereof to be incorporated into the
environmentally pollution-free anti-corrosive pigment composition
is not restricted to any specific range, but it in general ranges
from 0 to 20% by mass and preferably 2 to 15% by mass on the basis
of the total mass of the pigment composition.
[0039] The foregoing condensed calcium phosphate can be mixed with
an alkaline earth metal compound, an organic phosphonic acid or a
carboxylic acid possessing a chelating ability and/or a neutralized
salt thereof according to either the dry mixing technique or the
wet mixing technique. In particular, when the environmentally
pollution-free anti-corrosive pigment composition is applied to an
anti-corrosive paint and it is apprehended that the alkaline
component present in the alkaline earth metal compound reacts with
resins to thus cause gelation or an increase in viscosity, these
components are reacted, under wet conditions, with one another in
advance according to the wet mixing technique and the resulting
product may be used after drying the same and then firing or
pulverizing it.
[0040] The environmentally pollution-free anti-corrosive pigment
composition according to the present invention may, if necessary,
be subjected to a surface-treatment while taking into consideration
the dispersibility of the anti-corrosive pigment particles which
mainly comprise condensed calcium phosphate or the miscibility
thereof with vehicles used when used as an anti-corrosive paint.
The surface-treatment may be any known one ordinary used for
accomplishing the foregoing purpose and specific examples of such
surface-treated composition include those surface-treated with at
least one member selected from the group consisting of higher fatty
acids or derivatives thereof, acidic phosphoric acid esters or
derivatives thereof, rhodinic acid or derivatives thereof, or
silane coupling agents.
[0041] Examples of the foregoing higher fatty acids or derivatives
thereof include capric acid, lauric acid, myristic acid, palmitic
acid, stearic acid, oleic acid, linoleic acid, linolenic acid, or
metal salts thereof or amides thereof, examples of the foregoing
acidic phosphoric acid esters or derivatives thereof are monomethyl
acidic phosphate, dimethyl acidic phosphate, diethyl acidic
phosphate, methyl ethyl acidic phosphate, n-propyl acidic
phosphate, isopropyl acidic phosphate, n-butyl acidic phosphate and
isobutyl acidic phosphate; examples of the foregoing rhodinic acid
or derivatives thereof are rhodinic acid, naturally occurring rosin
or metal salts thereof or amides thereof, and examples of the
foregoing silane coupling agents include vinyl trichloro-silane and
vinyl tris(.beta.-methoxy-ethoxy) silane.
[0042] When using the environmentally pollution-free anti-corrosive
pigment composition according to the present invention by
incorporating it into an anti-corrosive paint, the anti-corrosive
pigment composition can be applied to not only the conventionally
used solvent type paints, but also water-based paints which have
attracted much attention with respect to the recent problems of
environmental pollution (such as water-soluble resin-containing
paints, dispersion type ones, emulsion type ones), as well as
powdery paints. Binders for paints usable herein are not restricted
to specific ones, may be a variety of resins and specific examples
thereof include boiled oils, oily varnishes; various kinds of
synthetic resins for paints such as phenolic resins, amino resins,
epoxy resins, urethane resins, vinyl resins, acrylic resins,
fluorine plastics, silicone resins and polyester resins; rubber
derivatives such as chlorinated rubber and cyclized rubber; and
other fibrin or cellulose derivatives, which may be used alone or
in any combination thereof. Moreover, when the environmentally
pollution-free anti-corrosive pigment composition according to the
present invention is dispersed in the foregoing resin for paints,
the condensed calcium phosphate, the alkaline earth metal compound,
the organic phosphonic acid or carboxylic acid and/or the neutral
salt thereof may be separately added to the resin for paints
without mixing these component in advance and the resulting mixture
is kneaded together to thus form an anti-corrosive paint, in situ,
which is excellent in the anti-corrosive effect.
[0043] When the environmentally pollution-free anti-corrosive
pigment composition according to the present invention is used in
an anti-corrosive paint, it is desirable to used the pigment
composition of the present invention alone, but the pigment
composition of the present invention may be used in combination
with other kinds of anti-corrosive paints.
[0044] In addition to the foregoing applications of the
environmentally pollution-free anti-corrosive pigment composition
according to the present invention to the anti-corrosive paints,
the paint composition of the invention may likewise be used in the
applications in which it serves as an inhibitor, and the
applications as an anti-corrosive pigment, for instance, the
addition thereof to anti-corrosive oils, the incorporation thereof
into plastic products which are used together with metals in one
united body and accordingly, the application of the composition is
not restricted to any specific one.
EXAMPLES
[0045] The present invention will hereunder be described in more
detail with reference to the following Working Examples and
Comparative Examples, but the scope of the present invention is not
restricted to these specific Examples and Comparative Examples at
all. In the following Examples and Comparative Examples, the terms
"%" and "part" used for specifying the concentrations and contents
therein means "% by mass" and "part by mass", unless otherwise
specified.
1. Synthesis of Condensed Calcium Phosphate A
[0046] To a flask, there were added 100 g of calcium carbonate and
173 g of commercially available 85% phosphoric acid (molar ratio:
Ca/P:0.67), followed by the reaction of these substances at
80.degree. C. for 3 hours with stirring. After allowing the
reaction solution to cool, it was fired for 30 hours in a dryer
maintained at a temperature of 250.degree. C. to thus form
condensed calcium phosphate A. This condensed calcium phosphate A
is a mixture of, for instance, CaH.sub.2P.sub.2O.sub.7 and
Ca.sub.4H.sub.2(P.sub.3O.sub.10).sub.2.
2. Synthesis of Condensed Calcium Phosphate B
[0047] To a flask, there were added 100 g of calcium carbonate and
154 g of commercially available 85% phosphoric acid (molar ratio:
Ca/P:0.75), followed by the reaction of these substances at
80.degree. C. for 3 hours with stirring. After allowing the
reaction solution to cool, it was fired for 30 hours in a dryer
maintained at a temperature of 250.degree. C. to thus form
condensed calcium phosphate B. This condensed calcium phosphate B
is a mixture of, for instance, CaH.sub.2P.sub.2O.sub.7,
Ca.sub.3H.sub.2(P.sub.2O.sub.7).sub.2 and
Ca.sub.4H.sub.2(P.sub.3O.sub.10).sub.2.
3. Synthesis of Condensed Calcium Phosphate C
[0048] To a flask, there were added 100 g of calcium carbonate and
113.7 g of polyphosphoric acid (molar ratio: Ca/P:0.74), followed
by the reaction of these substances at 80.degree. C. for 3 hours
with stirring. After allowing the reaction solution to cool, it was
fired for 30 hours in a dryer maintained at a temperature of
230.degree. C. to thus form condensed calcium phosphate C. This
condensed calcium phosphate C is a mixture of, for instance,
Ca.sub.2P.sub.2O.sub.7 and CaH.sub.2P.sub.2O.sub.7.
Examples 1 to 10 and Comparative Examples 1 to 6
[0049] The condensed calcium phosphates A to C prepared above,
alkaline earth metal compounds, and/or organic phosphonic acids or
carboxylic acids and/or neutral salts thereof were mixed together,
under dry conditions, in the mixing ratios specified in the
following Table 1 to thus form environmentally pollution-free,
anti-corrosive pigment compositions of Examples 1 to 10,
respectively.
[0050] Separately, there were admixed together, under dry
conditions, calcium metaphosphate (different from condensed calcium
phosphate) and magnesium oxide (Comparative Example 1); and
aluminum tripolyphosphate ("K-FRESH" available from TEIKA Co.,
Ltd.) (aluminum tripolyphosphate corresponding to a compound
represented by the foregoing Formula (1) wherein z=3) and calcium
metaphosphate (Comparative Example 2), in the mixing ratios
specified in the following Table 1 to thus form anti-corrosive
pigments, respectively. In addition, there were used, as
anti-corrosive pigments, zinc phosphate-containing aluminum
tripolyphosphate ("K-WHITE AZP500" available from TEIKA Co., Ltd.)
(Comparative Example 3), calcium-modified aluminum tripolyphosphate
("K-WHITE Ca650" available from TEIKA Co., Ltd.) (Comparative
Example 4), zinc oxide-modified aluminum tripolyphosphate ("K-WHITE
#105" available from TEIKA Co., Ltd.) (Comparative Example 5) and
zinc phosphate ("ZPF" available from Sakai Chemical Industry Co.,
Ltd.) (Comparative Example 6). More specifically, samples used in
Comparative Examples 3 to 6 were commercially available
anti-corrosive pigments. TABLE-US-00001 TABLE 1 Compositions of
Anti-Corrosive Pigment Compositions Sample No. Examples 1 2 3 4 5 6
Phosphoric acid salt Condensed calcium phosphate A 100 85 90
Condensed calcium phosphate B 95 70 Condensed calcium phosphate C
65 Alkaline earth metal compound Calcium oxide 15 Magnesium oxide
10 5 Calcium metasilicate 30 35 Compositions of Anti-Corrosive
Pigments (or Pigment Compositions) Sample No. Ex. Comp. Ex. 7 8 9
10 1 2 Phosphoric acid salt Condensed calcium phosphate A 80
Condensed calcium phosphate B 86 88 Condensed calcium phosphate C
97 Calcium metaphosphate 95 Aluminum tripolyphosphate 80 Alkaline
earth metal compound Calcium oxide 17 11 9 Magnesium oxide 5
Calcium metasilicate 20 Organic phosphonic acid or carboxylic acid
and/or neutral salt thereof 2-Hydroxy phosphono-acetic acid 3
Citric acid 3 Calcium citrate 3 Tannic acid 3
Test 1: Evaluation of Environmentally Pollution-Free,
Anti-Corrosive Pigment Compositions When Using the Same in Air
Drying Type Epoxy Resin-Based Paint or Coating
[0051] Each of the anti-corrosive pigments prepared in Examples 1
to 10 and Comparative Examples 1 to 6 was incorporated into an
epoxy resin-based paint and each resulting anti-corrosive paint was
inspected for the anti-corrosive effect.
Preparation of Air Drying Type Epoxy Resin-Based Paint
[0052] There were dispersed and admixed together, 4 parts of each
of the foregoing anti-corrosive pigments, 26 parts of an epoxy
resin solution (available from Mitsui Petrochemical Industries,
Ltd., having a xylene content of 75%), 5 parts of titanium oxide,
15 parts of talc, 25 parts of calcium carbonate, 2 parts of an
anti-sagging agent, 2 parts of an anti-settling agent, one part of
anti-foaming agent, 12 parts of xylene and 8 parts of isopropyl
alcohol to thus prepare each corresponding base paint material.
Regarding the hardener therefor, to 68 parts of polyamide resin,
there was added 32 parts of xylene, followed by the sufficient
mixing of these ingredients for the dissolution of the former into
the latter to thus give a desired hardener. Then each paint sample
was prepared by sufficiently blending 80 parts of each base paint
material and 20 parts of the hardener prepared above.
Preparation of Test Plate
[0053] Each paint thus prepared was coated on a cold-rolled steel
plate: JIS G3141 SPCC-SB (150.times.70.times.1.0 mm; available from
Nippon TACT Co., Ltd.) using a brush in a film thickness of 40
.mu.m as determined after drying the coated film. Then the coated
film was dried at room temperature over 2 weeks.
Method of Salt Spray Test
[0054] After making a crosscut pattern, which arrived even at the
surface of the basis material or the steel plate, the test plate
was placed within a salt spray test device maintained at a
temperature of 35.degree. C., while the coated paint film was
sprayed with a 5% aqueous sodium chloride solution at a rate of 1
kg/cm.sup.2/hour over 500 hours to thus inspect the test plate for
the rust and blistering observed or generated on the flat portions
of the coated film, and the width of the rust (hereunder referred
to as "corrosion width") determined from the center line of the
crosscut portion.
Evaluation Method and Evaluation Criteria
[0055] Both flat and crosscut portions on each coated steel plate
obtained after the foregoing salt spray test procedures were
inspected for the anti-corrosive effect in this salt spray
test.
[0056] In respect of the flat portion, the anti-corrosive effect
was evaluated on the basis of the size of the area of the portion
on which rust and blistering were generated. On the other hand, the
anti-corrosive effect on the crosscut portion was evaluated by
determining the length of the rust and blistering from the center
line of the cut portion, which was herein defined to be "corrosion
width". The results of the anti-corrosive effect thus evaluated are
shown in the following Table 2 according to the evaluation scores
ranging from 0 to 5.
[0057] In this connection, the anti-corrosive effect on the flat
portions is evaluated on the basis of the criteria according to
ASTM D610-68 (1970) for the rust generation-inhibitory effect and
on the basis of the criteria according to ASTM D714-59 (1965) for
the blistering-inhibitory effect, respectively. As will be seen
from the data listed in Table 2, the greater the score of the test
sample, the higher the anti-corrosive effect. TABLE-US-00002 TABLE
2 Flat Portion Rust-Generation Blistered Crosscut Portion Score
Area Area Corrosion Width 5 Less than 0.03% 0% Less than 1 mm 4
0.03%.about.less 0%.about.less 1 mm.about.less than 0.3% than 0.2%
than 2 mm 3 0.3%.about.less 0.2%.about.less 2 mm.about.less than
1.0% than 0.5% than 4 mm 2 1.0%.about.less 0.5%.about.less 4
mm.about.less than 3.0% than 1.0% than 7 mm 1 3.0%.about.less
1.0%.about.less 7 mm.about.less than 10% than 3.0% than 10 mm 0 Not
less than Not less than Not less than 10% 3.0% 10 mm
Results of Test 1
[0058] As will be seen from the data as shown in the following
Table 3, the environmentally pollution-free anti-corrosive pigment
compositions according to the present invention (Examples 1 to 10)
show excellent anti-corrosive effect as compared with those
observed for the anti-corrosive compositions of Comparative
Examples 1 and 2 and the commercially available ones (Comparative
Examples 3 to 6). TABLE-US-00003 TABLE 3 Anti-Corrosive Effect Flat
Portion Crosscut Portion Sample No. Rust Blistering Corrosion
Example 1 5 4 4 Example 2 5 5 5 Example 3 5 5 5 Example 4 5 5 5
Example 5 5 5 4 Example 6 5 5 5 Example 7 5 5 5 Example 8 5 5 5
Example 9 5 5 5 Example 10 5 5 5 Comp. Ex. 1 4 4 3 Comp. Ex. 2 4 3
3 Comp. Ex. 3 4 2 3 Comp. Ex. 4 4 3 3 Comp. Ex. 5 4 4 3 Comp. Ex. 6
4 3 3
Test 2: Evaluation of Anti-Corrosive Pigment Compositions When
Using the Same in Air Drying Type Medium Oil Alkyd Resin-Based
Paint or Coating
[0059] Each of the anti-corrosive pigments prepared in Examples 1
to 10 and Comparative Examples 1 to 6 according to the foregoing
methods was incorporated into an alkyd resin-based paint and each
resulting anti-corrosive paint was inspected for the anti-corrosive
effect and the storage stability.
Preparation of Air Drying Type Medium Oil Alkyd Resin-Based
Paint
[0060] There were dispersed and admixed together, 8 parts of each
of the foregoing anti-corrosive pigments, 30 parts of a medium oil
alkyd resin solution (TERPEN: 50%), 11 parts of talc, 40 parts of
calcium carbonate, 1 parts of an anti-sagging agent, 0.5 part of an
anti-skinning agent, one part of a dryer and 8.5 parts of mineral
spirit to thus prepare each corresponding paint.
Preparation of Test Plate
[0061] Each paint thus prepared was coated twice on a cold-rolled
steel plate: JIS G3141 SPCC-SB (150.times.70.times.1.0 mm;
available from Nippon TACT Co., Ltd.) using a brush in a film
thickness of 70 .mu.m as determined after drying the coated film.
Then, the coated film was dried at room temperature over 2
weeks.
Salt Spray Test and Method for Evaluation
[0062] Salt spray tests were carried out by repeating the same
procedures used in the foregoing Test 1 and each test plate (both
flat and crosscut portions) was inspected for the anti-corrosive
effect by the salt spray test according to the same evaluation
method and evaluated on the same evaluation criteria, shown in the
foregoing Table 2, like Test 1.
Storage Stability Test and Method for Evaluation
[0063] Each paint prepared according to the foregoing method was
introduced into a 250 ml volume mayonnaise bottle, followed by
tightly stoppering the bottle, maintaining the bottle in a
thermostatic chamber maintained at a temperature of 50.degree. C.
for 30 days for the evaluation of the storage stability of these
paints.
[0064] The viscosity of each sample paint was determined before and
after the completion of the storage stability test using a
Brookfield type viscometer and further the particle size thereof
was likewise determined before and after the completion of the
storage stability test using a fineness gauge. Each paint was
evaluated according to the following criteria: .largecircle.: The
difference between the viscosities observed before and after the
storage stability test is less than 10% and there was not observed
any change in the particle size; .chi.: The paint shows not less
than 10% of the viscosity change (thickening) or it shows an
increase of the particle size.
Results of Test 2
[0065] As will be seen from the data as shown in the following
Table 4, the environmentally pollution-free anti-corrosive pigment
compositions according to the present invention (Examples 1 to 10)
show excellent anti-corrosive effect as compared with those
observed for the anti-corrosive compositions of Comparative
Examples 1 and 2 and the commercially available ones (Comparative
Examples 3 to 6). In addition, with respect to the storage
stability, the anti-corrosive paints of Comparative Examples 3, 5
and 6 which comprise zinc components have particularly low storage
stabilities due to the occurrence of seeding, but the
anti-corrosive pigments of Examples 1 to 10 which are free of any
zinc component show excellent storage stabilities. TABLE-US-00004
TABLE 4 Anti-Corrosive Effect Paint Flat Portion Crosscut Portion
Storage Sample No. Rust Blistering Corrosion Stability Example 1 5
4 4 .largecircle. Example 2 5 5 5 .largecircle. Example 3 5 5 5
.largecircle. Example 4 5 5 5 .largecircle. Example 5 5 5 4
.largecircle. Example 6 5 5 5 .largecircle. Example 7 5 5 5
.largecircle. Example 8 5 5 5 .largecircle. Example 9 5 5 5
.largecircle. Example 10 5 5 5 .largecircle. Comp. Ex. 1 4 3 3
.largecircle. Comp. Ex. 2 4 3 3 .largecircle. Comp. Ex. 3 4 3 2 X
Comp. Ex. 4 4 3 3 .largecircle. Comp. Ex. 5 4 4 3 X Comp. Ex. 6 3 3
3 X
INDUSTRIAL APPLICABILITY
[0066] The present invention can herein provide an anti-corrosive
pigment composition which is free of any environmental pollution
since it never comprises any harmful heavy metal element such as
lead and/or chromium as well as zinc and thus shows an excellent
anti-corrosive effect. This anti-corrosive pigment composition can
be incorporated into various kinds of paints and it is quite useful
as an anti-corrosive material for a variety of metal materials.
[0067] Further, the anti-corrosive pigment composition can be used
according to the methods identical to those applied to other
anti-corrosive materials or in various applications similar to
those for the anti-corrosive pigments, for instance, the
composition can be added to anti-corrosive oils and the composition
can likewise be used in the method of using the same as an
inhibitor.
* * * * *