U.S. patent application number 09/092307 was filed with the patent office on 2001-08-16 for phosphoric acid group-containing non-aqueous dispersion and a process for the application thereof.
Invention is credited to MASUDA, YUTAKA, NAKAHATA, AKIMASA, YUKAWA, YOSHIYUKI.
Application Number | 20010014713 09/092307 |
Document ID | / |
Family ID | 26487572 |
Filed Date | 2001-08-16 |
United States Patent
Application |
20010014713 |
Kind Code |
A1 |
YUKAWA, YOSHIYUKI ; et
al. |
August 16, 2001 |
PHOSPHORIC ACID GROUP-CONTAINING NON-AQUEOUS DISPERSION AND A
PROCESS FOR THE APPLICATION THEREOF
Abstract
This invention relates to a phosphoric acid group-containing
non-aqueous dispersion wherein polymer particles are dispersed in a
solution of a macromolecular dispersion stabilizer dissolved in an
organic solvent, said polymer particle being a particle of polymer
comprising a phosphoric acid group-containing polymerizable
unsaturated monomeric unit as a constituent component. With use of
said phosphoric acid group-containing non-aqueous dispersion, there
can be improved interlayer adhesivity between a metallic coating
film, which is formed from a leafing type aluminum flake pigment,
and another coating film adjacent thereto, without reducing the
excellent effects such as dense metallic feeling of the coated
surface, a chrome plating-like finish, and strong brightness
feeling and strong flip-flop perperties, which are produced by such
a metallic coating film.
Inventors: |
YUKAWA, YOSHIYUKI;
(HIRATSUKA-SHI, JP) ; MASUDA, YUTAKA;
(FUJISAWA-SHI, JP) ; NAKAHATA, AKIMASA;
(HIRATSUKA-SHI, JP) |
Correspondence
Address: |
WENDEROTH LIND AND PONACK
2033 K STREET N W SUITE 800
WASHINGTON
DC
20006
|
Family ID: |
26487572 |
Appl. No.: |
09/092307 |
Filed: |
June 5, 1998 |
Current U.S.
Class: |
524/547 ;
523/523 |
Current CPC
Class: |
C08F 230/02
20130101 |
Class at
Publication: |
524/547 ;
523/523 |
International
Class: |
C08K 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 5, 1997 |
JP |
163,441/97 |
Jun 18, 1997 |
JP |
161,415/97 |
Claims
1. A phosphoric acid group-containing non-aqueous dispersion which
comprises polymer particles dispersed in a solution of
macromolecular dispersion stabilizer dissolved in an organic
solvent, said polymer particle being a particle of polymer which is
composed of a phosphoric acid group-containing polymerizable
unsaturated monomeric unit as a constituent component.
2. A non-aqueous dispersion of claim 1 wherein the phosphoric acid
group-containing polymerizable unsaturated monomer is selected from
the group consisting of (i) a compound which contains, in one
molecule, both at least one phosphoric acid group having the
formula--O--PO(OH)(R.sub.1) wherein R.sub.1 is a hydroxyl group, a
phenyl group or an alkyl group having 1 to 20, in particular 2 to
10, carbon atoms, and at least one polymerizable unsaturated bond;
(ii) an equimolar adduct of glycidyl (meth)acrylate with a
mono-C.sub.1 20 alkyl phosphoric acid ester; and (iii) a compound
having the formulaCH.sub.2.dbd.CX--CO--(YO).sub.n--OPO(O- H).sub.2
wherein X denotes a hydrogen atom or a methyl group, Y denotes an
alkylene group having 2 to 4 carbon atoms, and n denotes an integer
of 3 to 30, in particular 3 to 20.
3. A non-aqueous dispersion of claim 1 wherein the phosphoric acid
group-containing polymerizable unsaturated monomer is
acid-phosphoxy-C.sub.2-10 alkyl (meth)acrylate.
4. A non-aqueous dispersion of claim 1 wherein the polymer
particles are formed either by the polymerization of a phosphoric
acid group-containing polymerizable unsaturated monomer, or by the
copolymerization of a phosphoric acid group-containing
polymerizable unsaturated monomer with another copolymerizable
monomer.
5. A non-aqueous dispersion of claim 4 wherein said another
copolymerizable monomer is a (meth)acrylic acid ester.
6. A non-aqueous dispersion of claim 4 wherein said
copolymerization is conducted between 0.5 to 50% by weight of
phosphoric acid group-containing polymerizable unsaturated monomer
and 99.5 to 50% by weight of another copolymerizable monomer, based
on the total amount of these two monomers.
7. A non-aqueous dispersion of claim 1 wherein said macromolecular
dispersion stabilizer is substantially incompatible with said
polymer particles although compatible with said organic
solvent.
8. A non-aqueous dispersion of claim 1 wherein said macromolecular
dispersion stabilizer has a weight average molecular weight ranging
from 1,000 to 50,000, a hydroxyl value ranging from 0.5 to 200 and
an acid value ranging from 0.5 to 100.
9. A non-aqueous dispersion of claim 1 wherein said macromolecular
dispersion stabilizer is an acrylic resin type dispersion
stabilizer which has an average of 0.2 to 1.2 polymerizable
unsaturated bonds per molecule.
10. A non-aqueous dispersion of claim 1 wherein said polymer
particles has an average particle size ranging from 0.01 to 1
.mu.m.
11. A non-aqueous dispersion of claim 1 which is produced by
subjecting monomeric components which contain a phosphoric acid
group-containing polymerizable unsaturated monomer to dispersion
polymerization in a solution of macromolecular dispersion
stabilizer dissolved in an organic solvent.
12. A non-aqueous dispersion of claim 11 wherein 0.1 to 70% of
macromolecular dispersion stabilizer and 99.9 to 30% of monomeric
components, based on the total weight of solid contents of both
macromolecular dispersion stabilizer and monomeric components, are
polymerized.
13. A non-aqueous dispersion of claim 11 wherein the concentration
of the total solid contents of both macromolecular dispersion
stabilizer and monomeric components ranges from 5 to 60% by
weight.
14. A method for forming a multi-layer coating film by applying a
leafing type aluminum flake-containing metallic coating (A), and,
after curing the same, applying a clear coating (B) on the coated
surface of said metallic coating (A), which method is characterized
by using, as said clear coating (B), a coating composition which
contains the phosphoric acid group-containing non-aqueous
dispersion of claim 1.
15. A method of claim 14 wherein said clear coating (B) contains 1
to 80% by weight (as solid contents) of phosphoric acid
group-containing non-aqueous dispersion, based on the total solid
contents.
16. A method for forming a multi-layer coating film which is
characterized by applying a base coating (C) which contains a
phosphoric acid group-containing resin composition, and, without
curing the same, applying a leafing type aluminum flake-containing
metallic composition (D), and, after curing both of said base
coating (C) and said metallic composition (D), applying, on the
coated surface of said metallic composition (D), a clear coating
(B) which contains the phosphoric acid group-containing non-aqueous
dispersion of claim 1.
17. A method of claim 16 wherein said phosphoric acid
group-containing resin composition is either (P-1) a polymer which
comprises, as constituent components, both phosphoric acid
group-containing unsaturated monomer and hydroxyl group-containing
unsaturated monomer, and which accordingly contains both phosphoric
acid group and hydroxyl group, or (P-2) the phosphoric acid
group-containing non-aqueous dispersion of claim 1.
18. A method of claim 16 wherein said metallic composition (D) is a
composition which contains both a leafing type aluminum flake and
an organic solvent.
19. A method of claim 18 wherein said organic solvent which is used
for the metallic composition (D) comprises an organic solvent which
has a surface tension of at least 27 dyn/cm.
20. A method of claim 16 wherein said clear coating (B) contains 1
to 80% by weight (as solid contents) of phosphoric acid
group-containing non-aqueous dispersion, based on the total solid
contents.
Description
[0001] This invention relates to a non-aqueous dispersion which
comprises, as dispersed particles, a phosphoric acid
group-containing polymer, and to a process for the formation of a
leafing type aluminum flake-containing metallic multi-layer coating
film which is formed with use of said non-aqueous dispersion.
[0002] There has already been known a technique to form, on a
substrate such as an automobile body panel, a multi-layer coating
film, by applying an aluminum flake pigment-containing metallic
coating on said substrate, and then applying, on the resultant
coated surface, a clear coating which is capable of forming a
transparent film.
[0003] The aluminum flake pigment to be compounded in a metallic
coating is classified into a leafing type one and a non-leafing
type one. In a metallic coating film which contains a leafing type
aluminum flake pigment, the aluminum flake pigment floats up to the
surface of said coating film (which phenomenon is called leafing)
to form a continuous and dense aluminum plane which is oriented
substantially parallel to the coated surface, resulting in the
achievement of special effects such as a chrome plating-like
finish, glittering brightness and strong flip-flop properties.
[0004] This metallic coating film per se is, however, inferior in
chemical resistance such as acid resistance since aluminum flake
pigment floats up to the surface of said coating film. In order to
overcome this defect, the coated surface of said metallic coating
film is usually coated with a clear coating. However, when a clear
coating is applied onto the coated surface of a metallic coating
film while the metallic coating is uncured, the orientation of
leafing type aluminum flake is disturbed, resulting in the
deterioration of a chrome plating-like finish (which phenomenon is
called mottling). On the other hand, when a clear coating is
applied after the metallic coating film is heat-cured, the
interlayer adhesivity between the metallic coating film and the
clear coating film is caused to be insufficient. Hence, it has been
impossible to fully produce the above-mentioned various
advantageous effects of a leafing type aluminum flake-containing
metallic coating film.
[0005] As for a non-leafing type aluminum flake, it is uniformly
dispersed in the whole of a coating film without causing leafing.
Hence, when a clear coating is applied onto the surface of a
metallic coating, there occurs neither mottling nor the reduction
in interlayer adhesivity. However, brightness feeling and flip-flop
effects are weak, and, moreover, it is difficult to achieve a
metallic coating film having a chrome plating-like finish.
[0006] In view of the above situation, the inventors of this
invention made an assiduous study on how to improve the interlayer
adhesivity between a metallic coating film and an adjacent film,
without causing reduction in the above-mentioned special effects
(e.g., dense metallic appearance of the coated surface, a chrome
plating-like finish, strong brightness and flip-flop effects)
possessed by a leafing type aluminum flake pigment-containing
metallic coating film.
[0007] As a result, the inventors have newly developed a phosphoric
acid group-containing non-aqueous dispersion, and have found out
that, when a clear coating which contains said non-aqueous
dispersion is applied on a metallic cured film which contains the
above-mentioned leafing type aluminum flake pigment, the interlayer
adhesivity between the metallic coating film and the clear coating
can be improved.
[0008] The inventors have further found out that the interlayer
adhesivity between a leafing type aluminum flake pigment-containing
metallic coating film and another coating film can be improved by
applying a base coating which contains a phosphoric acid
group-containing resin composition, and, without curing said base
coating, applying a leafing type aluminum flake pigment-containing
metallic composition on the coated surface of said base coating,
and, after curing these coatings, applying on the resultant coated
surface a clear coating which contains the above-mentioned
phosphoric acid group-containing non-aqueous dispersion.
[0009] Thus, this invention provides a non-aqueous dispersion
(hereinafter referred to as non-aqueous dispersion of this
invention) which comprises polymer particles dispersed in a
solution of macromolecular dispersion stabilizer dissolved in an
organic solvent, said polymer particles being particles of polymer
which comprises, as a constitutent component, a phosphoric acid
group-containing polymerizable unsaturated monomeric unit.
[0010] This invention also provides a process (hereinafter referred
to as Application Process I of this invention) for the formation of
a multi-layer coating film which process is characterized by using,
as a clear coating, a coating which contains the non-aqueous
dispersion of this invention, when forming a multi-layer coating
film by applying a leafing type aluminum flake-containing metallic
coating, and, after curing said coating, applying a clear coating
on the resultant coated surface.
[0011] This invention further provides a process (hereinafter
referred to as Application Process II of this invention) for the
formation of a multi-layer coating film which process is
characterized by applying a base coating which contains a
phosphoric acid group-containing resin composition, and, without
curing said base coating, applying a leafing type aluminum flake
pigment-containing metallic composition on the resultant coated
surface of said base coating, and, after curing these coatings,
applying on the resultant coated surface a clear coating which
contains the non-aqueous dispersion of this invention.
[0012] The following is a further detailed explanation of the
non-aqueous dispersion of this invention and the Application
Processes I and II of this invention.
[0013] Non-Aqueous Dispersion of This Invention
[0014] A non-aqueous dispersion which comprises polymer particles
dispersed in a solution of macromolecular dispersion stabilizer
dissolved in an organic solvent, said polymer particles being
produced by polymerizing monomeric unit which contains a phosphoric
acid group-containing polymerizable unsaturated monomer.
[0015] The polymer of the polymer particles in the non-aqueous
dispersion of this invention can be produced by polymerizing either
a phosphoric acid group-containing polymerizable unsaturated
monomer alone or a monomeric component which comprises a phosphoric
acid group-containing polymerizable unsaturated monomer and another
copolymerizable monomer.
[0016] Examples of said phosphoric acid group-containing
polymerizable unsaturated monomer include a compound which has, in
one molecule, both at least one phosphoric acid group represented
by formula
--OPO(OH)(R.sub.1) (1)
[0017] wherein R.sub.1 is a hydroxyl group, a phenyl group or an
alkyl group having 1 to 20, especially 2 to 10, carbon atoms
[0018] and at least one polymerizable unsaturated bond. Concretely,
there are mentioned acid-phosphoxy-C.sub.1-20 (especially
C.sub.2-10)alkyl (meth)acrylates such as acid-phosphoxyethyl
acrylate, acid-phosphoxyethyl methacrylate, acid-phosphoxypropyl
acrylate, acid-phosphoxypropyl methacrylate, acid-phosphoxydecyl
acrylate, acid-phosphoxydecyl methacrylate and the like.
[0019] As a phosphoric acid group-containing polymerizable
unsaturated monomer, there can also be used an equimolar adduct of
glycidyl (meth)acrylate with mono-C.sub. 1-20 alkylphosphoric acid
ester.
[0020] Furthermore, as a phosphoric acid group-containing
polymerizable unsaturated monomer, there can also be used compounds
represented by the formula
CH.sub.2.dbd.CX--CO--(YO).sub.n--OPO(OH).sub.2 (2)
[0021] wherein X denotes hydrogen atom or methyl group; Y denotes
alkylene group having 2 to 4 carbon atoms; and n denotes an integer
of 3 to 30, especially 3 to 20.
[0022] This monomer can be prepared for example by adding alkylene
oxide to (meth)acrylic acid to form polyalkylene glycol monoester,
which is then allowed to react with phosphorus oxychloride to form
phosphate monoester, which is then hydrolyzed. This phosphorus
oxychloride can be replaced with orthophosphoric acid,
metaphosphoric acid, phosphoric acid anhydride, phosphorus
trichloride or phosphorus pentachloride. The above-mentioned
alkylene oxide can be used in an amount of at least stoichiometric
amount in accordance with the number "n" in the above formula (2),
preferably for example, in an amount ranging from 3 to 60 moles per
mole of (meth)acrylic acid. Alkylene oxide has preferably 2 to 4
carbon atoms, and its examples include ethylene oxide, propylene
oxide and butylene oxide. The above-mentioned addition reaction can
be completed within 0.5 to 5 hours at a temperature of 40 to
200.degree. C. The reaction of monoesterification of phosphorus
oxychloride after the above addition reaction can be completed
within 0.5 to 5 hours at a temperature of 0 to 100.degree. C.
Phosphorus oxychloride may be used almost in a stoichiometric
amount. According to necessity, it may be used in an amount ranging
from 1 to 3 moles per mole of the adduct. Thereafter, the resultant
monoester is hydrolyzed by a usual method, and, thus, the compounds
of formula (2) are obtained. Examples of said compounds include
acid-phosphoxyhexa (or dodeca) (oxypropylene) monomethacrylate.
[0023] Among the above-mentioned phosphoric acid group-containing
polymerizable unsaturated monomers, acid-phosphoxy-C.sub.2-10 alkyl
(meth)acrylates are especially preferable.
[0024] These phosphoric acid group-containing polymerizable
unsaturated monomers may be used either alone or in combination of
two or more species.
[0025] As another monomeric unit which is copolymerizable with the
above-mentioned phosphoric acid group-containing polymerizable
unsaturated monomers, there can be used compounds which have at
least one polymerizable unsaturated bond in one molecule.
Concretely, the following can be mentioned:
[0026] a) Esters of (meth)acrylic acid
[0027] For example, C.sub.1-18 alkyl esters of (meth)acrylic acid
such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl
(meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate,
hexyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate
and stearyl (meth)acrylate; glycidyl ester such as glycidyl
(meth)acrylate; C.sub.2-8 alkenyl esters of (meth)acrylic acid such
as allyl (meth)acrylate; C.sub.2-8 hydroxyalkyl esters of
(meth)acrylic acid such as hydroxyethyl (meth)acrylate and
hydroxypropyl (meth)acrylate; C.sub.3-18 alkenyloxy alkyl esters of
(meth)acrylic acid such as allyloxyethyl (meth)acrylate; esters
between C.sub.2-8 hydroxyalkyl esters of (meth)acrylic acid and
caprolactone which are available under tradenames PLACCEL FA-1,
FA-2, FA-3, FA-4, FA-5, FM-1, FM-2, FM-3, FM-4, FM-5 and FM-6
(produced by Daicel Chemical Industries, Ltd.); diesters between
(meth)acrylic acid and glycols such as ethylene glycol and
propylene glycol.
[0028] b) Vinyl aromatic compounds
[0029] For example, styrene, .alpha.-methylstyrene, vinyl toluene,
p-chlorostyrene, vinylpyridine and divinyl benzene, and the
like.
[0030] c) .alpha.,.beta.-Ethylenically unsaturated acids
[0031] For example, (meth)acrylic acid, maleic acid and itaconic
acid
[0032] d) (Meth)acrylic acid amides
[0033] For example, (meth)acrylamide, n-butoxymethyl
(meth)acrylamide and n-methylol (meth)acrylamide.
[0034] e) Others
[0035] For example, (meth)acrylonitrile, methylisopropenyl ketone,
vinyl acetate, Veova monomer (tradename of a product produced by
Shell Chemical), vinyl propionate, vinyl pivalate, isocyanate ethyl
(meth)acrylate, perfluorocyclohexyl (meth)acrylate, p-styrene
sulfonamide, N-methyl-p-styrene sulfonamide and
.gamma.-methacryloxy propyltrimethoxy silane.
[0036] Among the above monomers, esters of (meth)acrylic acid are
preferably used. It is desirable that at least a part of the same
should be hydroxyl group-containing unsaturated monomers such as
C.sub.2-8 hydroxyalkyl esters of (meth)acrylic acid or esters
between C.sub.2-8 hydroxyalkyl esters of (meth)acrylic acid and
caprolactone.
[0037] The monomeric component from which to prepare the polymer of
polymer particles in the non-aqueous dispersion of this invention
comprises a phosphoric acid group-containing polymerizable
unsatureated monomer as an essential ingredient and, if necessary,
another copolymerizable monomer. The ratio of these monomers are
not specifically restricted, and may optionally be changed
according to objective. Generally, however, phosphoric acid
group-containing polymerizable unsatureated monomer accounts for
0.1-100% by weight, especially 0.5-50% by weight, most desirably
3-30% by weight based on the total of phosphoric acid
group-containing polymerizable unsatureated monomer and the other
monomer, and said other monomer accounts for 99.9-0% by weight,
especially 99.5-50% by weight, most preferably 97-70% by
weight.
[0038] As for the above-mentioned hydroxyl group-containing
unsaturated monomer, it is usable in an amount of 0-80% by weight,
especially 1-50% by weight, most desirably 5-40% by weight based on
the total monomers.
[0039] The non-aqueous dispersion of this invention can be prepared
by polymerizing the above-mentioned monomeric components into the
form of particles in a solution of macromolecular dispersion
stabilizer in an organic solvent. There can resultantly be obtained
a non-aqueous dispersion wherein polymer particles derived from the
above-mentioned monomeric components are dispersed in a solution of
macromolecular dispersion stabilizer dissolved in an organic
solvent.
[0040] The purpose of using a macromolecular dispersion stabilizer
is to disperse polymer particles stably in a dispersion. Usable
macromolecular dispersion stabilizer is compatible with organic
solvent in said dispersion, but is substantially incompatible with
coexistent particles of polymer which comprises, as a constituent
component, a phosphoric acid group-containing polymerizable
unsaturated monomer unit.
[0041] Examples of such a macromolecular dispersion stabilizer
include the followings, which may be used either alone or in
combination of two or more species.
[0042] 1) Polyester macromonomer (1a) which is produced by adding,
by esterification, a glycidyl ester of (meth)acrylic acid to a
carboxyl group of a self condensation polyester resin of a fatty
acid which has a hydroxyl group such as 12-hydroxystearic acid; and
Polymer (1b) which is produced by polymerizing a polymerizable
monomer with a polymerizable unsaturated bond in said polyester
macromonomer (1a).
[0043] 2) Polymer (2a) which is produced by polymerizing the
above-mentioned polyester macromonomer (1a) with a polymerizable
monomer which contains a glycidyl ester of (meth)acrylic acid, and
by further adding .alpha.,.beta.-ethylenically unsaturated acid to
glycidyl group in the resultant polymer so as to introduce
polymerizable unsaturated bond. Usually, the amount of said
polymerizable unsaturated bond to be introduced is preferably, on
average, 0.2 to 1.2 in number, especially 0.5 to 1 in number, per
molecule.
[0044] 3) Hydroxyl group-containing acrylic resin which is produced
by polymerizing a polymerizable monomeric component which contains
both C.sub.4-22 alkyl ester of (meth)acrylic acid and a hydroxyl
group-containing polymerizable monomer.
[0045] 4) Acrylic resin (4a) which is produced by introducing a
polymerizable unsaturated bond, by means of adding
.alpha.,.beta.-ethylenically unsaturated acid, into a glycidyl
group of a hydroxyl group-containing acrylic resin which is
produced by polymerizing a polymerizable monomeric component which
contains C.sub.4-22 alkyl ester of (meth)acrylic acid, a hydroxyl
group-containing polymerizable monomer such as C.sub.2-8
hydroxyalkyl esters of (meth)acrylic acid and glycidyl ester of
(meth)acrylic acid; and Acrylic resin (4b) which is produced by
introducing a polymerizable unsaturated bond, by means of adding
glycidyl ester of (meth)acrylic acid, into a carboxyl group of a
hydroxyl group-containing acrylic resin which is produced by
polymerizing a polymerizable monomeric component which contains
monoester between an alkyl having four or more carbon atoms and
(meth)acrylic acid, a hydroxyl group-containing polymerizable
monomer and .alpha.,.beta.-ethylenically unsaturated acid. In each
of these resins (4a) and (4b), usually 0.2 to 1.2 in number,
especially 0.5 to 1 in number, on average, of said polymerizable
unsaturated bond is preferably introduced per one molecule.
[0046] 5) Alkyl-etherified melamine resin which has a high
allowability for mineral spirit.
[0047] 6) Oil-modified alkyd resin having an oil length of at least
15% by weight, preferably 20 to 40% by weight. Or alkyd resin into
which a polymerizable unsaturated bond has been introduced by means
of adding glycidyl ester of (meth)acrylic acid to carboxyl group in
said oil-modified alkyd resin. On average, 0.2 to 1.2 in number,
especially 0.5 to 1 in number, of said polymerizable unsaturated
bond is preferably introduced into one molecule.
[0048] 7) Alkyd resin which is produced by adding, by urethane
formation, an equimolar reaction product between polyisocyanate and
a hydroxyl group-containing polymerizable monomer to hydroxyl group
of an oil-modified alkyd resin having at least 15% by weight,
preferably 20 to 40% by weight, of oil length so as to introduce a
polymerizable unsaturated bond. On average, 0.2 to 1.2 in number,
especially 0.5 to 1 in number, of said polymerizable unsaturated
bond is preferably introduced into one molecule.
[0049] 8) Cellulose acetate butyrate having a polymerizable
unsaturated bond which is prepared by subjecting a hydroxyl group
of cellulose acetate butyrate to a urethane reaction with a monomer
such as isocyanate ethyl(meth)acrylate and an equimolar adduct of
isophorone diisocyanate with hydroxyethyl acrylate, each of which
has both an isocyanate group and a polymerizable unsaturated bond.
On average, 0.2 to 1.2 in number, especially 0.5 to 1 in number, of
said polymerizable unsaturated bond is preferably introduced into
one molecule.
[0050] As for the glycidyl ester of (meth)acrylic acid,
polymerizable monomer, .alpha.,.beta.-ethylenically unsaturated
acid, C.sub.4-22 alkyl ester of (meth)acrylic acid, a hydroxyl
group-containing polymerizable monomer and C.sub.2-8 hydroxyalkyl
esters of (meth)acrylic acid in the above dispersion stabilizers,
there are usable one or more species which are selected from the
afore-mentioned examples.
[0051] Generally, the above-mentioned various dispersion
stabilizers have a weight average molecular weight ranging from
about 1,000 to about 50,000, preferably from about 2000 to about
35,000, and most desirably from about 3,000 to about 20,000.
[0052] Moreover, said dispersion stabilizers have a hydroxyl value
which ranges generally from 0.5 to 200, especially from 5 to 170,
and most desirably from 20 to 140, and have an acid value which
ranges generally from 0.5 to 100, especially from 3 to 60, and most
desirably from 5 to 40.
[0053] Especially preferable among the above dispersion stabilizers
are acrylic resins mentioned in the above 3) and 4) which are
easily dissolved in a low polarity organic solvent such as
aliphatic hydrocarbon, and which have good weatherability. Acrylic
resin type dispersion stabilizer which has preferably an average of
0.2 to 1.2 polymerizable unsaturated bonds per one molecule is most
desirable since it graft-polymerizes with polymer particles to
improve the stability of dispersion. Especially desirable is a
polymer (dispersion stabilizer) which is prepared with use of a low
polarity monomer, as a main component, such as C.sub.4-22 alkyl
ester of methacrylic acid like n-butyl methacrylate, 2-ethylhexyl
methacrylate, dodecyl methacrylate, lauryl methacrylate and stearyl
methacrylate, and, if necessary, together with styrene, methyl
(meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate,
(meth)acrylic acid, glycidyl (meth)acrylate and 2-hydroxyethyl
(meth)acrylate. To said polymer, furthermore, glycidyl
(meth)acrylate, (meth)acrylic acid or isocyanate ethylmethacrylate
is preferably added so as to introduce polymerizable double
bond.
[0054] Preferably used in the non-aqueous dispersion of this
invention is an organic solvent which dissolves macromolecular
dispersion sabilizer, and which is capable of dispersing polymer
particles without substantially dissolving the same, and which, in
particular, has a boiling point at most 150.degree. C. There are
concretely mentioned the followings, which may be employed either
alone or in combination of two or more species.
[0055] Hydrocarbon solvent such as heptane, octane, toluene, xylene
and mineral spirit; ester solvent such as ethyl acetate, n-butyl
acetate, isobutyl acetate, methyl Cellosolve acetate and butyl
Carbitol acetate; ketone solvent such as methylethyl ketone,
methylisobutyl ketone and diisobutyl ketone; alcohol solvent such
as methanol, ethanol, isopropanol, n-butanol and sec-butanol; ether
solvent such as n-butyl ether, dioxane, ethyleneglycol
monomethylether and ethyleneglycol monoethylether; SWASOL 310,
SWASOL 1000 and SWASOL 1500 which are tradenames of petroleum type
aromatic hydrocarbon solvent produced by Cosmo Oil Co.
[0056] The non-aqueous dispersion of this invention can be
produced, for example, by uniformly dissolving the above-mentioned
macromolecular dispersion stabilizer in an organic solvent, and
subsequently dispersion-polymerizing a monomeric component which
contains phosphoric acid group-containing polymerizable unsaturated
monomer. It is important that said monomeric component before the
dispersion-polymerization should be readily soluble in the solution
of macromolecular dispersion stabilizer dissolved in an organic
solvent, but that the polymer particles which are formed after the
dispersion-polymerization should substantially be insoluble in said
solution. In thus obtained non-aqueous dispersion of this
invention, the polymer which is derived from monomeric component
which comprises a phosphoric acid group-containing polymerizable
unsaturated monomer is dispersed, in the form of particles, in a
solution of organic solvent which contains a macromolecular
dispersion stabilizer dissolved therein. The average particle size
of the dispersed polymer particles preferably ranges from 0.01 to 1
.mu.m, especially from 0.05 to 0.6 .mu.m.
[0057] Dispersion polymerization of the monomeric component which
contains a phosphoric acid group-containing polymerizable
unsaturated monomer in a solution of a macromolecular dispersion
stabilizer dissolved in an organic solvent can easily be conducted
by a known method such as radical polymerization. The constituent
ratio of these components in the polymerization reaction is not
particularly restricted. As for the preferable ratio of
macromolecular dispersion stabilizer to monomeric component for
example, macromolecular dispersion stabilizer accounts for 3 to
90%, in particular 5 to 70%, while monomeric component accounts for
97 to 10%, in particular 95 to 30%, based on the total weight of
solid contents of these two components. On the basis of the total
weight of macromolecular dispersion stabilizer, monomeric component
and organic solvent, the total amount of macromolecular dispersion
stabilizer and monomeric component accounts for 5 to 70%, in
particular 10 to 60%, while organic solvent accounts for 95 to 30%,
in particular 90 to 40%.
[0058] When a crosslinkable functional group such as hydroxyl group
is existent in the molecule of macromolecular dispersion stabilizer
and/or polymer particles, a three-dimensionally crosslinked coating
film can be formed by means of compounding a crosslinking agent
with the non-aqueous dispersion of this invention.
[0059] It is also possible to cause crosslinkage in the interior of
polymer particle by means of using, as the other copolymerizable
monomer which is usable in combination with the phosphoric acid
group-containing polymerizable unsaturated monomer, a monomer
having at least two polymerizable unsaturated bonds in a molecule
such as divinyl benzene or diesters of glycol such as ethylene
glycol or propylene glycol with (meth)acrylic acid, in the
monomeric component with which to prepare the polymer particle.
Intraparticle-crosslinked polymer can be prepared also by using,
together with the above-mentioned monomer, another monomer which
has a self crosslinking reactive functional group such as
N-alkoxy-methylated acrylamide or
.gamma.-methacryloxytrialkoxysilane in dispersion
polymerization.
[0060] The non-aqueous dispersion of this invention is usable for a
coating composition or an adhesive. According to purpose, there may
be compounded an additive such as crosslinking agent, other polymer
particles, resin for coating composition, pigment, curing catalyst,
UV light absorber, painted surface adjustor, antioxidant, fluidity
adjustor, pigment dispersing agent and silane coupling agent.
[0061] Examples of crosslinking agent include melamine resin,
polyisocyanate compound which may be blocked, epoxy compound and
hydrolyzable alkoxysilyl compound.
[0062] As an example of said other polymer particles, there can be
mentioned both a powder which can be produced by separating
particles from an aqueous dispersion of polymer particles, and a
dispersion which can be produced by replacing water of said aqueous
dispersion of polymer particles with an organic solvent, said
aqueous dispersion of polymer particles being obtained by
subjecting a polymerizable monomeric component which contains a
small amount of monomer having, in one molecule, at least two
polymerizable unsaturated bonds to emulsion-polymerization in an
aqueous medium, with use of an anionic or nonionic surfactant.
Generally, said other polymer particles are preferably compounded
in a proportion of 0.1 to 30 parts by weight, in particular 1 to 20
parts by weight, on the basis of 100 parts by weight of solid
contents of the total of macromolecular dispersion stabilizer and
phosphoric acid group-containing polymer particles.
[0063] Examples of resin for coating composition include cellulose
acetate butyrate, epoxy resin, polyester resin, alkyd resin and
acrylic resin. These resins for coating composition preferably
account for 0.1 to 100 parts by weight, in particular 1 to 60 parts
by weight, based on 100 parts by weight of solid contents of the
total of macromolecular dispersion stabilizer and phosphoric acid
group-containing polymer particles.
[0064] As pigment, there are usable one, two or more species which
are selected from usual solid color pigment and metallic pigment
for paint. Examples of solid color pigment include quinacridone
type one such as quinacridone; azo type one such as pigment red;
phthalocyanine type one such as phthalocyanine blue and
phthalocyanine green; titanium white; barium sulfate; barium
carbonate; carbon black; baryta; clay; silica; chrome vermilion;
permanent red; perylene vermilion; titanium yellow; antimony
yellow; indanthrene type one; chrome green; ultramarine; cyanine
blue; cobalt violet; and quinacridone violet. Examples of metallic
pigment include flake pigment which gives metallic feeling or light
interference to a coating film, such as mica-like iron oxide, mica,
stainless steel, brass, titanium oxide-coated mica and iron
oxide-coated mica, which are not restrictive however.
[0065] A coating composition which contains the non-aqueous
dispersion of this invention can be applied to a material to be
coated such as metal (e.g., steel plate and surface-treated steel
plate) and plastic, as a primer, an intermediate coat or a top
coat. A film formed from the coating composition which contains the
non-aqueous dispersion of this invention is treated under a
condition which may appropriately be chosen according to the
species of crosslinking agent etc. which are contained according to
necessity. Hence, there can be employed normal temperature drying,
normal temperature curing, heat drying and heat curing. Thus formed
coating film is excellent in weatherability, interlayer adhesivity,
chipping resistance, and the like.
[0066] Application Process I of This Invention
[0067] A process to form a multi-layer coating film which is
characterized in that, when a leafing type aluminum
flake-containing metallic coating (A) is applied, and, after
curing, a clear coating is applied on the resultant coated surface,
there is used as said clear coating a coating (B) which contains
the non-aqueous dispersion of this invention.
[0068] A leafing type aluminum flake, as stated above, tends to
float up to the surface of a coating film which contains the same
(which phenomenon is called leafing), forming a continuous aluminum
plane which is oriented substantially parallel to the coated
surface in the surface layer of said coated surface. However, when
a clear coating is applied onto an uncured surface of a metallic
coating film, the orientation of aluminum flake which has floated
to the surface layer is disturbed, resulting in the occurrence of
mottling. On the other hand, when a clear coating is applied after
the metallic coating film is heat-cured, the interlayer adhesivity
between the metallic coating film and the clear coating film does
not become sufficient.
[0069] The application process of this invention has been developed
with a view to achieving, as a main object, the improvement of the
interlayer adhesivity between said two coating films in a system
wherein a clear coating is applied after a leafing type aluminum
flake-containing metallic coating film is heat-cured. This process
is characterized by using, as said clear coating, a coating
composition which contains the non-aqueous dispersion of this
invention.
[0070] For the metallic coating (A) which is used in the
application process of this invention, there can be employed a
liquid coating which comprises a vehicle component and a leafing
type aluminum flake metallic pigment.
[0071] For the above-mentioned vehicle component, there can be used
a known vehicle component for metallic coating, such as a vehicle
comprising a resin having a crosslinkable functional group such as
a hydroxyl group and a crosslinking agent. Examples of said
crosslinkable functional group-containing resin include an acrylic
resin, a polyester resin, an alkyd resin, etc. each of which has
two or more hydroxyl groups in one molecule. Of these resins, a
hydroxyl group-containing acrylic resin is particularly preferred.
As for crosslinking agent, there is suitably used a melamine resin
which is reactive with said crosslinkable functional group.
Concretely, there is preferably used a partially or fully
etherified methylol melamine resin having 1 to 5 triazine nuclei
wherein a part or the whole of the methylol groups of methylol
melamine has been etherified with a monohydric alcohol having 1 to
8 carbon atoms. An imino group-containing melamine resin or a
(blocked) polyisocyanate compound can also be used as a
crosslinking agent. As for the compounding ratio of the
crosslinkable functional group-containing resin to the crosslinking
agent, the crosslinkable functional group-containing resin accounts
for 50 to 90% by weight, particularly 65 to 80% by weight, while
the crosslinking agent accounts for 50 to 10% by weight,
particularly 45 to 20% by weight, based on the total of the solid
contents of these two components.
[0072] The aluminum of leafing type aluminum flake pigment which is
used for metallic coating (A) is, when mechanically ground,
preferably coated on its surface with a low surface tension
component such as stearic acid. Said leafing type aluminum flake
pigment appropriately has a lengthwise direction size of 2 to 50
.mu.m and a thickness of 0.1 to 2 .mu.m. When a coating composition
which contains such a leafing type aluminum flake pigment is
applied, the aluminum flake floats up to the surface layer of the
coated surface, and is oriented almost parallel to the coated
surface, and, thus, there can be formed a metallic coating film
having a high density, strong brightness and a chrome plating-like
finish.
[0073] In metallic coating (A), said leafing type aluminum flake
pigment is compounded preferably in a proportion of 1 to 50 parts
by weight, in particular 3 to 25 parts by weight, on the basis of
100 parts (solid) by weight of the above-mentioned vehicle
component (i.e., total amount of a crosslinkable functional
group-containing resin and a crosslinking agent).
[0074] The metallic coating (A) can be produced by mixing and
dispersing the above components in an organic solvent. If
necessary, a coloring pigment, an extender pigment, an
anti-settling agent, a UV light absorber, etc. may be further
compounded.
[0075] As for the organic solvent used for metallic coating (A),
any solvent for painting may be employed without special
restriction. Particularly preferable is a solvent for painting
which contains an organic solvent having a surface tension as high
as at least 27 dyn/cm, especially 30 dyn/cm. Examples of such
solvents include hydrocarbon type ones such as xylene, toluene,
tetralin and solvent naphtha; ester type ones such as Cellosolve
and butyl Cellosolve; alcohol type ones such as decanol, dodecanol
and benzylalcohol; ketone type ones such as cycloheptane and
cyclohexane.
[0076] The organic solvent used for metallic coating (A) may either
consist of the above-mentioned high surface tension organic solvent
alone or be a mixture system comprising said high surface tension
organic solvent and other organic solvent. In said mixture system,
the above-mentioned high surface tension organic solvent preferably
accounts for at least 50% by weight, in particular at least 60% by
weight, based on the total solvents in the mixture system.
[0077] As for the concentration of the solid content of metallic
coating (A) when applied, it may normally range from about 5% by
weight to about 60% by weight.
[0078] The metallic coating (A) can be applied onto a metallic or a
plastic substrate such as an automobile body panel, by
electrostatic coating, spray coating or the like, either directly
or after applying a primer (e.g., a cationic electrocoating) onto
the surface of said metallic or a plastic substrate, heat-curing
the resulting primer film, then applying an intermediate coating if
necessary, and appropriately heat-curing the resulting intermediate
coating film. Wet-on-wet application of the metallic coating (A) on
uncured film of intermediate coating, these two coatings
subsequently heat-cured, can effectively shorten the application
step. Generally, the film of the metallic coating (A) has
preferably a thickness ranging from 1 to 20 .mu.m, in particular
from 2 to 10 .mu.m, as a cured film. The film of metallic coating
(A) can be cured by heating at a temperature of about 100 to about
180.degree. C. for about 10 to 40 minutes.
[0079] Clear coating (B) which is to be applied on the heat-cured
coated surface of metallic coating (A) may form either a colorless
transparent coating film or a colored transparent coating film. As
clear coating (B), there is usable a non-aqueous dispersion type
liquid paint which contains the non-aqueous dispersion of this
invention (a non-aqueous dispersion wherein particles of polymer
which comprises phosphoric acid group-containing polymerizable
unsaturated monomer unit as a constituent component are dispersed
in a solution of macromolecular dispersion stabilizer dissolved in
an organic solvent), and which, if necessary, further comprises
other normal resin for paint, solid color pigment or metallic
pigment, UV light absorber, etc. mixed with an organic solvent, and
which is capable of forming a film which is clear at least to such
an extent that the metallic feeling of the metallic coating (A) can
be seen through.
[0080] In clear coating (B), the content (as solid) of the
non-aqueous dispersion of this invention may be varied in a wide
range. Generally, however, said content preferably ranges from 1 to
80% by weight, in particular from 3 to 50% by weight, most
desirably from 5 to 30% by weight, based on the total solid
contents.
[0081] Examples of other usual resin for paint which may be
compounded with clear coating (B) include acrylic resin, polyester
resin, alkyd resin, fluororesin, urethane resin and
silicon-containing resin, each of which has a crosslinkable
functional group such as hydroxyl group, epoxy group, carboxyl
group, silanol group or the like. Crosslinkable functional
group-containing acrylic resin is preferable in particular. A resin
which contains the above-mentioned crosslinkable functional group
may be used in combination with a crosslinking agent such as
melamine resin, urea resin, (blocked) polyisocyanate compound,
epoxy compound or resin, carboxyl group-containing compound or
resin, acid anhydride and alkoxysilane group-containing compound or
resin, each of which is reactive with the above-mentioned
functional group. As melamine resin, there is preferably used a
partially or fully etherified methylol melamine resin having 1 to 5
triazine nuclei wherein a part or the whole of the methylol groups
of methylol melamine has been etherified with a monohydric alcohol
having 1 to 8 carbon atoms. An imino group-containing melamine
resin is also usable. As for the compounding ratio of the
crosslinkable functional group-containing resin to the crosslinking
agent in said other usual resin for paint, the crosslinkable
functional group-containing resin accounts for 50 to 90% by weight,
particularly 65 to 80% by weight, while the crosslinking agent
accounts for 50 to 10% by weight, particularly 45 to 20% by weight,
based on the total of the solid contents of these two
components.
[0082] In clear coating (B), the constituent proportion of the
non-aqueous dispersion of this invention to said other usual resin
for paint (including crosslinking agent) may be optional depending
on the objective. Generally, however, the non-aqueous dispersion of
this invention accounts for 0.01 to 100% by weight (as solid), in
particular 2 to 20% by weight (as solid), further especially
desirably 3 to 15% by weight (as solid), while said other usual
resin for paint accounts for 99.99 to 0% by weight, in particular
98 to 80% by weight, and most desirably 97 to 85% by weight, based
on the total amount of solid contents of these two components.
[0083] As examples of organic solvent in clear coating (B), there
are mentioned solvents like hydrocarbon type ones such as hexane,
heptane, xylene, toluene and cyclohexane; ester type ones such as
methyl acetate, ethyl acetate, ethylene glycol acetate monomethyl
ether and diethylene glycol acetate monomethyl ether; ether type
ones such as isopropylether, ethylene glycol monomethyl ether and
diethylene glycol monobutyl ether; alcohol type ones such as ethyl
alcohol, butyl alcohol and hexyl alcohol; ketone type ones such as
methyl isobutyl ketone, methylethyl ketone, isophorone and
acetophenone.
[0084] In Application Process I of this invention, metallic coating
(A) is applied in the above-mentioned manner, and, after the
resulting coating film is heat-cured, clear coating (B) is
applied.
[0085] The concentration of solid content of clear coating (B) when
applied preferably ranges from about 30 to about 80% by weight.
This clear coating (B) is applied by electrostatic method or spray
method so that the thickness of film as cured may be 5 to 100
.mu.m, preferably 20 to 80 .mu.m, and, then, the film is cured.
[0086] In a multi-layer coating film composed of a leafing type
aluminum flake-containing metallic coating film and a clear coating
film, according to the above-mentioned Application Process I of
this invention, when a clear coating film is formed from a clear
coating composition which contains the non-aqueous dispersion of
this invention, there can be improved the interlayer adhesivity
between said metallic coating film and clear coating film without
decreasing the effects of a chrome plating-like finish with dense
and strongly bright coated surface which is derived from aluminum
plane which is continuously oriented in parallel to the surface
layer of the metallic coating film.
[0087] Moreover, thus formed multi-layer coating film has good heat
insulation as compared with other coating films. Therefore, in an
automobile whose body panel is coated with the multi-layer coating
film of this invention, the inside temperature is hard to be
affected by outdoor conditions.
[0088] The leafing aluminum flake which is oriented in parallel to
the surface layer of the metallic coating film has its surface
coated with stearic acid etc., and has a low surface tension.
Hence, when the coated surface of this leafing aluminum flake is
coated with clear coating, wettability sometimes decreases. By use
of a clear coating which contains the non-aqueous dispersion of
this invention, however, wettability is improved.
[0089] There is a further merit as follows. Even though a resin for
painting which comprises a functional group (e.g., epoxy group)
reactive with phosphoric acid group is contained in the non-aqueous
dispersion of this invention and in the clear coating (B) of
Application Process I of this invention, these two groups are
prevented from reacting with each other since phosphoric acid
group-containing polymer is protected with a dispersion stabilizer,
with the result that storage stability is not deteriorated.
[0090] Application Process II of This Invention
[0091] A process to form a multi-layer coating film which is
characterized by applying base coating (C) which contains a
phosphoric acid group-containing resin composition, and, without
curing this base coating (C), applying leafing type aluminum flake
pigment-containing metallic composition (D), and, after curing this
metallic composition (D), applying clear coating (B) which contains
the non-aqueous disperion of this invention on the coated surface
of said metallic composition (D).
[0092] Base Coating (C) which Contains Phosphoric Acid
Group-Containing Resin Composition
[0093] Base coating (C) is a paint which is to be applied on a
material to be coated, prior to the application of metallic
composition (D) which is mentioned later. By providing the coating
film of this base coating (C) in adjacent to, and just under the
coating film of said metallic composition (D), there can remarkably
be improved the adhesivity between metallic composition (D) and
intermediate coating or primer coating which is applied under the
metallic composition (D).
[0094] Base coating (C) is a paint which contains a phosphoric acid
group-containing resin composition. As said phosphoric acid
group-containing resin composition, one or more species may be
selected for use from the followings:
[0095] (P-1) Polymer containing a phosphoric acid group and a
hydroxyl group in one molecule, which is prepared with use of a
phosphoric acid group-containing unsaturated monomer and a hydroxyl
group-containing unsaturated monomer as constituent components.
[0096] (P-2) Phosphoric acid group-containing non-aqueous
dispersion, i.e., the non-aqueous dispersion of this invention,
which comprises polymer particles dispersed in a solution of
macromolecular dispersion stabilizer dissolved in an organic
solvent, polymer of said particles comprising a phosphoric acid
group-containing unsaturated monomer unit as a constituent
component.
[0097] As phosphoric acid group-containing unsaturated monomer
which is to be used for the preparation of polymer (P-1) containing
a phosphoric acid group and a hydroxyl group, there can be
mentioned the phosphoric acid group-containing unsaturated monomer
set forth above which constitutes, as monomeric component, the
polymer particles in the non-aqueous dispersion of this
invention.
[0098] The hydroxyl group-containing unsaturated monomer is a
compound having, in one molecule, a hydroxyl group and a
polymerizable unsaturated bond. Examples of said monomer include
C.sub.2-20, in particular C.sub.2-10 hydroxyalkyl (meth)acrylates
such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate,
hydroxybutyl (meth)acrylate and the like. Examples of this monomer
further include PLACCEL's FA-1, FA-2, FA-3, FA-4, FA-5, FM-1, FM-2,
FM-3, FM-4, FM-5 and FM-6 (trade names of the products of Daicel
Chemical Industries, Ltd.), which are each an ester of the
above-mentioned hydroxyalkyl (meth)acrylate and caprolactone.
[0099] The polymer (P-1) can be produced by copolymerizing the
phosphoric acid group-containing unsaturated monomer, the hydroxyl
group-containing unsaturated monomer, and, if necessary, an
N-alkoxymethylamide group-containing unsaturated monomer and/or
other unsaturated monomer.
[0100] The N-alkoxymethylamide group-containing unsaturated monomer
is a compound having an N-alkoxymethylamide group and a
polymerizable unsaturated bond in one molecule. Examples of said
compound include N-C.sub.1-6 alkoxymethyl (meth)acrylamides such as
N-methoxymethyl (meth)acrylamide, N-ethoxymethyl (meth)acrylamide,
N-butoxymethyl (meth)acrylamide, N-propoxymethyl (meth)acrylamide
and the like. Examples of said other unsaturated monomer include
C.sub.1-22 alkyl (meth)acrylates such as methyl (meth)acrylate,
ethyl (meth)acrylayte, propyl (meth)acrylate, butyl (meth)acrylate
and the like; vinyl aromatic compounds such as styrene,
vinyl-toluene and the like; vinyl monomers such as acrylonitrile,
vinyl acetate, vinyl chloride and the like; olefins such as
ethylene, propylene and the like; and carboxyl group-containing
unsaturated compounds such as (meth)acrylic acid, maleic acid,
maleic anhydride and the like.
[0101] As for the ratio of the phosphoric acid group-containing
monomer to the hydroxyl group-containing monomer in polymer (P-1),
the phosphoric acid group-containing monomer preferably accounts
for 1 to 50% by weight, in particular 5 to 30% by weight, while the
hydroxyl group-containing monomer accounts for 1 to 50% by weight,
in particular 5 to 30% by weight, based on the total monomers
constituting the polymer (P-1). N-alkoxymethylamide
group-containing unsaturated monomer preferably accounts for 30% by
weight or less, in particular 1 to 20% by weight, based on the
total monomers constituting the polymer (P-1). The remainder is the
other unsaturated monomer.
[0102] The copolymerization of these monomers is preferably
conducted by solution polymerization. The resulting polymer (P-1)
preferably has a hydroxyl value of 5 to 150 mg KOH/g, in particular
10 to 120 mg KOH/g, more desirably 30 to 110 mg KOH/g; an acid
value, based on the phosphoric acid group, of generally 10 to 150
mg KOH/g, in particular 20 to 130 mg KOH/g; and a number-average
molecular weight of 1,000 to 100,000, in particular 3,000 to
50,000, more desirably 5,000 to 30,000.
[0103] When comprising N-alkoxymethylamide group-containing monomer
unit, this polymer (P-1) becomes self crosslinkable.
[0104] Polymer (P-1), when free from any N-alkoxymethylamide
group-containing monomer unit, has no self-crosslinkability or
self-curability. When used in combination with an
N-alkoxymethylamide group-containing monomer, however, polymer
(P-1) can be subjected to crosslinking. When polymer (P-1) which is
free from any N-alkoxymethylamide group-containing monomer unit is
used in combination with a polymer having N-alkoxymethylamide
group-containing monomer units in base coating (C), the base
coating (C) becomes crosslinkable.
[0105] Base coating (C) can be prepared by dissolving or
dispersing, in an organic solvent, a phosphoric acid
group-containing resin composition such as the above-mentioned
polymer (P-1) and the non-aqueous dispersion of this invention
(P-2), together with, if necessary, resin for coating composition,
crosslinking agent, other polymer particles, extender pigment,
curing catalyst, UV light absorber, painted surface adjustor,
antioxidant, fluidity adjustor, pigment dispersing agent and silane
coupling agent.
[0106] Examples of resin for coating composition include polyester
resin, alkyd resin, acrylic resin, epoxy resin and cellulose
acetate butyrate. These resins for coating composition preferably
account for 0.1 to 100 parts by weight, in particular 1 to 60 parts
by weight, based on 100 parts by weight of solid content of the
phosphoric acid group-containing resin composition.
[0107] Examples of crosslinking agent include melamine resin,
polyisocyanate compound which may be blocked and epoxy
compound.
[0108] As an example of said other polymer particles, there can be
mentioned both a powder which can be produced by separating
particles from an aqueous dispersion of polymer particles, and a
dispersion which can be produced by replacing water of said aqueous
dispersion of polymer particles with an organic solvent, said
aqueous dispersion of polymer particles being obtained by
subjecting a polymerizable monomeric component which contains a
small amount of monomer having at least two polymerizable
unsaturated bonds to emulsion-polymerization in an aqueous medium
with use of an anionic or nonionic surfactant. Generally, said
other polymer particles compounded preferably account for 0.1 to 30
parts by weight, in particular 1 to 20 parts by weight, on the
basis of 100 parts by weight of solid contents of the phosphoric
acid group-containing resin composition.
[0109] In Application Process II, base coating (C) is to be applied
prior to the application of metallic composition (D) which is
mentioned later. Base coating (C) can be applied onto a metallic or
a plastic substrate such as an automobile body panel, either
directly or after coating said substrate with a primer (e.g., a
cationic electrocoating), heat-curing the primer, and, if
necessary, further applying an intermediate coating, and then
appropriately heat-curing the intermediate coating. Wet-on-wet
application of the base coating (C) on uncured film of intermediate
coating can effectively shorten the application step.
[0110] Base coating (C) is applied by air spray, airless spray or
electrostatic coating. Thus applied coating film has preferably a
thickness ranging from 5 to 20 .mu.m, in particular from 10 to 15
.mu.m, as a cured film.
[0111] The film of base coating (C) per se can be crosslinked and
cured either at a normal temperature or by heating. In this
Application Process II, however, base coating (C) is applied, and,
without crosslinking or curing the resulting coating film, metallic
composition (D) which is mentioned later is applied on the uncured
film of base coating (C).
[0112] Leafing Type Aluminum Flake-Containing Metallic Composition
(D)
[0113] A composition to be applied on uncured film of base coating
(C). This composition mainly comprises a leafing type aluminum
flake pigment and an organic solvent.
[0114] As for said leafing type aluminum flake pigment and organic
solvent, there can be employed the same as those which are
mentioned with respect to the leafing type aluminum
flake-containing metallic coating (A) used in Application Process I
of this invention.
[0115] As for the proportion of leafing type aluminum flake pigment
to organic solvent in metallic composition (D), the leafing type
aluminum flake pigment accounts for 1 to 10% by weight, in
particular 3 to 7% by weight, while the organic solvent accounts
for 99 to 90% by weight, in particular 97 to 93% by weight, on the
basis of the total amount of these two components.
[0116] The metallic composition (D) can be produced by mixing and
dispersing a leafing type aluminum flake pigment in an organic
solvent. With the resultant dispersion, if necessary, an
anti-settling agent, a UV light absorber, etc. may be further
compounded.
[0117] The metallic composition (D) can be applied on uncured
coated surface of base coating (C) by electrostatic coating, spray
coating or the like. Generally, the film of the metallic
composition (D) has preferably a thickness ranging from 0.5 to 5
.mu.m, in particular from 0.8 to 3 .mu.m, as a cured film (which is
composed of a leafing type aluminum flake pigment only, or may
sometimes contain other solid contents).
[0118] After the metallic composition (D) is applied, it is
preferably heated at a temperature of about 100 to about
180.degree. C. for about 10 to 40 minutes, so that the coating film
of base coating (C) may be cured, and that the base coating (C) and
the metallic composition (D) may be tightly adhered to each
other.
[0119] Clear Coating (B)
[0120] After metallic composition (D) is applied, and both coating
films of base coating (C) and metallic composition (D) are cured,
this clear coating (B) is applied on the cured surface of metallic
composition (D). The clear coating (B) which is used in Application
Process I of this invention can be employed as it is.
[0121] In this Application Process II, after base coating (C) and
metallic composition (D) are applied and heat-cured, clear coating
(B) whose sol id content concentration at the time of application
has been adjusted to about 30 to about 80% by weight is applied by
electrostatic coating, spray coating or the like, so that the cured
film may have a thickness ranging from 5 to 100 .mu.m, preferably
from 20 to 80 .mu.m, and, then, the applied coating is cured. How
to cure clear coating (B) may optionally be chosen according to its
composition. In the case of heat curing, the coating is preferably
heated at a temperature of about 100 to about 180.degree. C. for
about 10 to 40 minutes.
[0122] The above-mentioned Application Process II of this invention
gives the following effects:
[0123] {circumflex over (1)} In a three-layer coating film which
comprises base coating film, leafing type aluminum flake-containing
metallic coating film and clear coating, when the base coating film
and the clear coating film are made to contain a specific
phosphoric acid group-containing component, there can remarkably be
improved the interlayer adhesivity in said three-layer coating film
without decreasing the effects of a chrome plating-like finish with
dense and strongly bright coated surface which is derived from
leafing type aluminum plane.
[0124] {circumflex over (2)} Thus formed multi-layer coating film
has good heat insulation as compared with other coating films.
Therefore, in an automobile whose body panel is coated with the
multi-layer coating film of this invention, the inside temperature
is hard to be affected by outdoor conditions.
[0125] {circumflex over (3)} The leafing type aluminum flake has
its surface coated with stearic acid etc. and has low surface
tension. Hence, when the coated surface of this leafing type
aluminum flake is coated with clear coating, wettability sometimes
decreases. In this invention, however, wettability of clear coating
is improved.
[0126] This invention is described below in more detail by way of
Examples. Part and % used in the following each mean a value based
on weight.
[0127] 1. Sample Preparation
[0128] 1) Piece to Be Coated
[0129] Onto a zinc phosphate-treated dull-finish steel plate having
a thickness of 0.8 mm, there was applied a thermosetting epoxy
resin type cationic electrocoating [Elecron 9600 (trade name of a
product of Kansai Paint Co., Ltd.] so as to form a film of about 20
.mu.m in thickness as cured. After the applied coating was cured at
170.degree. C. for 30 minutes, there was air sprayed, on thus cured
coating film, an intermediate coating for automobile [TP-37 Primer
Surfacer (trade name of a thermosetting polyester resin melamine
resin type organic solvent of Kansai Paint Co., Ltd.)] so as to
form a film of about 25 .mu.m in thickness as cured. Thus coated
plate was then left to stand at room temperature for 3 minutes, and
was used for the test piece.
[0130] 2) Metallic coatings (A)
[0131] (A-i)
[0132] There were mixed and dispersed, in an organic solvent
(xylene/toluene=1/1 by weight), 65 parts by weight of a polyester
resin (*1), 35 parts by weight of a melamine resin (*2) and 5 parts
by weight of a leafing type aluminum flake (*3), and, then, the
viscosity of the resultant mixture was adjusted to 13 seconds
(20.degree. C.) by Ford Cup No. 4.
[0133] (*1) Polyester Resin
[0134] Polyester resin of phthalic anhydride-hexahydrophthalic
anhydride type, having a number-average molecular weight of about
3,500, a hydroxyl value of 82 mg KOH/g and an acid value of 8 mg
KOH/g.
[0135] (*2) Melamine Resin
[0136] UBAN 28-60 (trade name of a product of Mitsui Toatsu
Chemicals, Inc.)
[0137] (*3) Leafing Aluminum Flake
[0138] [0620MS] (trade name of a paste containing 32% of mineral
spirit, each flake having a lengthwise direction size of 13.6 .mu.m
and a thickness of 0.4 .mu.m; product of Toyo Aluminium K. K.)
[0139] (A-ii) (for comparison)
[0140] There were mixed and dispersed, in an organic solvent
(xylene/toluene=1/1 by weight), 65 parts by weight of a polyester
resin (*1), 35 parts by weight of a melamine resin (*2) and 5 parts
by weight of a non-leafing type aluminum flake (*4), and, then, the
viscosity of the resultant mixture was adjusted to 13 seconds
(20.degree. C.) by Ford Cup No. 4.
[0141] (*4) Non-Leafing Aluminum Flake
[0142] ALUMIPASTE 7640 NS (trade name of a paste containing 32% of
mineral spirit, each flake having a lengthwise direction size of 17
.mu.m and a thickness of 0.5 .mu.m; product of Toyo Aluminium
K.K.)
[0143] 3) Macromolecular Dispersion Stabilizer for Phosphoric Acid
Group-Containing Non-Aqueous Dispersion
[0144] Dispersion Stabilizer 1
[0145] Into a usual reactor for the production of acrylic resin
which was equipped with stirrer, thermometer, reflux condenser,
etc., there were introduced 52 parts of xylene and 10 parts of
n-butanol, which were then heated and stirred. When the temperature
reached 125.degree. C., a mixture of the following monomers was
added dropwise over a period of four hours.
[0146] Styrene 20 parts
[0147] n-Butylacrylate 17 parts
[0148] 2-Ethylhexyl methacrylate 47 parts
[0149] 2-Hydroxyethyl acrylate 10 parts
[0150] Methacrylic acid 6 parts
[0151] .alpha.,.alpha.'-Azobisisobutyronitrile 3 parts
[0152] After the dropwise addition of the above monomeric mixture
was over, the resultant mixture was kept at 125.degree. C. for 30
minutes. Then, to said mixture, there was added dropwise a mixture
of 0.5 part of azobisdimethyl valeronitrile and 5 parts of xylene
over a period of one hour. The resultant mixture was stirred, while
kept at 125.degree. C. for three hours. Thus obtained resin
solution had a solid content of 60% and an acid value of 86.5. To
this resin solution, 1.2 parts of glycidyl methacrylate was added,
and the resultant mixture was subjected to addition reaction at
120.degree. C. until acid value became 83, and, thus, dispersion
stabilizer 1 was produced. This dispersion stabilizer 1 had a
weight average molecular weight of 12,000, a hydroxyl value of
48.4, an acid value of 83 and a solid content of 60%.
[0153] Dispersion Stabilizer 2
[0154] Into a usual reactor for the production of acrylic resin
which was equipped with stirrer, thermometer, reflux condenser,
etc., there were introduced 52 parts of xylene and 10 parts of
n-butanol, which were then heated and stirred. When the temperature
reached 125.degree. C., a mixture of the following monomers was
added dropwise over a period of four hours.
[0155] Methyl methacrylate 30 parts
[0156] n-Butylacrylate 15 parts
[0157] 2-Ethylhexyl methacrylate 47 parts
[0158] 2-Hydroxyethyl methacrylate 15 parts
[0159] Methacrylic acid 3 parts
[0160] .alpha.,.alpha.'-Azobisisobutyronitrile 3 parts
[0161] After the dropwise addition of the above monomeric mixture
was over, the resultant mixture was kept at 125.degree. C. for 30
minutes. Then, to said mixture, there was added dropwise a mixture
of 0.5 part of azobisdimethyl valeronitrile and 5 parts of xylene
over a period of one hour. The resultant mixture was stirred, while
kept at 125.degree. C. for three hours. Thus obtained resin
solution had a solid content of 60% and an acid value of 19.2. To
this resin solution, 1.2 parts of glycidyl methacrylate was added,
and the resultant mixture was subjected to addition reaction at
120.degree. C. until acid value became 16, and, thus, dispersion
stabilizer 2 was produced. This dispersion stabilizer 2 had a
weight average molecular weight of 12,000, a hydroxyl value of
64.7, an acid value of 16 and a solid content of 60%.
[0162] Dispersion Stabilizer 3
[0163] Into a usual reactor for the production of polyester resin
which was equipped with stirrer, thermometer, fractionater, reflux
condenser, etc., there was introduced a mixture of the following
reaction components, which was then subjected to a general
dehydration-condensatio- n reaction, and, thus, condensation was
achieved until acid value became 4.
[0164] Trimethylol propane 46.5 parts
[0165] Hexahydrophthalic acid 23.6 parts
[0166] Isophthalic acid 25.5 parts
[0167] Coconut oil fatty acid 35.8 parts
[0168] To the resin solution which was obtained by the above
condensation, 1.2 parts of isocyanate ethylmethacrylate was added,
and the resultant mixture was subjected to addition reaction until
isocyanate value became 0.5 or lower, and, thus, dispersion
stabilizer 3 was produced. This dispersion stabilizer 3 had a
weight average molecular weight of 30,000, a hydroxyl value of 114,
an oil length of 30%, an acid value of 4 and a solid content of
60%.
[0169] 4) Non-Aqueous Dispersion of This Invention
[0170] Non-Aqueous Dispersion (i) of This Invention
[0171] Into a usual reactor for the production of acrylic resin
which was equipped with stirrer, thermometer, reflux condenser,
etc., there were introduced 120 parts of xylene, 64 parts of
heptane and 55 parts of dispersion stabilizer 1, which were then
heated and stirred. When the temperature reached 100.degree. C., a
mixture of the following monomers and dispersion stabilizer 1 was
added dropwise over a period of five hours.
[0172] Methyl methacrylate 55 parts
[0173] Methylacrylate 10 parts
[0174] 2-Hydroxyethyl acrylate 20 parts
[0175] Acid-phosphoxyethyl methacrylate 15 parts
[0176] Dispersion stabilizer 1) 55 parts
[0177] .alpha.,.alpha.'-Azobisisobutyronitrile 1 parts
[0178] After the dropwise addition of the above mixture was over,
the resultant mixture was kept at 100.degree. C. for further 30
minutes. Then, to said mixture, there was added dropwise a mixture
of 0.5 part of azobisdimethyl valeronitrile and 20 parts of xylene
over a period of one hour. The resultant mixture was stirred, while
kept at 100.degree. C. for two hours. Then, said mixture was
cooled, and, thus, there was produced non-aqueous dispersion (i) of
this invention. In this dispersion, solid content was 45%, acid
value was 70, and phosphoric acid group-containing polymer
particles had a particle size of 300 nm.
[0179] Non-Aqueous Dispersion (ii) of This Invention
[0180] Into a usual reactor for the production of acrylic resin
which was equipped with stirrer, thermometer, reflux condenser,
etc., there were introduced 120 parts of xylene, 64 parts of
heptane and 55 parts of dispersion stabilizer 2, which were then
heated and stirred. When the temperature reached 100.degree. C., a
mixture of the following monomers and dispersion stabilizer 2 was
added dropwise over a period of five hours.
[0181] Methyl methacrylate 53 parts
[0182] Glycidyl methacrylate 2 parts
[0183] Methyl acrylate 10 parts
[0184] 2-Hydroxyethyl acrylate 20 parts
[0185] Acid-phosphoxyethyl methacrylate 15 parts
[0186] Dispersion stabilizer 2) 55 parts
[0187] .alpha.,.alpha.'-Azobisisobutyronitrile 1 parts
[0188] After the dropwise addition of the above mixture was over,
the resultant mixture was kept at 100.degree. C. for further 30
minutes. Then, to said mixture, there was added dropwise a mixture
of 0.5 part of azobisdimethyl valeronitrile and 20 parts of xylene
over a period of one hour. The resultant mixture was stirred, while
kept at 100.degree. C. for two hours. Then, said mixture was
cooled, and, thus, there was produced non-aqueous dispersion (ii)
of this invention which contained intra-particle-crosslinked
polymer particles. In this dispersion (ii), solid content was 45%,
acid value was 44, and phosphoric acid group-containing polymer
particles had a particle size of 250 nm.
[0189] Non-Aqueous Dispersion (iii) of This Invention
[0190] Into a usual reactor for the production of acrylic resin
which was equipped with stirrer, thermometer, reflux condenser,
etc., there were introduced 120 parts of xylene, 64 parts of
heptane and 55 parts of dispersion stabilizer 3, which were then
heated and stirred. When the temperature reached 100.degree. C., a
mixture of the following monomers and dispersion stabilizer 3 was
added dropwise over a period of five hours.
[0191] Methyl methacrylate 55 parts
[0192] Methyl acrylate 10 parts
[0193] 2-Hydroxyethyl acrylate 20 parts
[0194] Acid-phosphoxyethyl methacrylate 15 parts
[0195] Dispersion stabilizer 3) 55 parts
[0196] .alpha.,.alpha.'-Azobisisobutyronitrile 1 parts
[0197] After the dropwise addition of the above mixture was over,
the resultant mixture was kept at 100.degree. C. for further 30
minutes. Then, to said mixture, there was added dropwise a mixture
of 0.5 part of azobisdimethyl valeronitrile and 20 parts of xylene
over a period of one hour. The resultant mixture was stirred, while
kept at 100.degree. C. for two hours. Then, said mixture was
cooled, and, thus, there was produced non-aqueous dispersion (iii)
of this invention. In this dispersion (iii), solid content was 45%,
acid value was 40, and phosphoric acid group-containing polymer
particles had a particle size of 320 nm.
[0198] Non-Aqueous Dispersion (iv) of This Invention
[0199] Into a usual reactor for the production of acrylic resin
which was equipped with stirrer, thermometer, reflux condenser,
etc., there were introduced 120 parts of xylene, 64 parts of
heptane and 55 parts of dispersion stabilizer 2, which were then
heated and stirred. When the temperature reached 100.degree. C., a
mixture of the following monomers and dispersion stabilizer 2 was
added dropwise over a period of five hours.
[0200] Methyl methacrylate 55 parts
[0201] Methyl acrylate 10 parts
[0202] 2-Hydroxyethyl acrylate 20 parts
[0203] Acid-phosphoxydecyl methacrylate 15 parts
[0204] Dispersion stabilizer 2) 55 parts
[0205] .alpha.,.alpha.'-Azobisisobutyronitrile 1 parts
[0206] After the dropwise addition of the above mixture was over,
the resultant mixture was kept at 100.degree. C. for further 30
minutes. Then, to said mixture, there was added dropwise a mixture
of 0.5 part of azobisdimethyl valeronitrile and 20 parts of xylene
over a period of one hour. The resultant mixture was stirred, while
kept at 100.degree. C. for two hours. Then, said mixture was
cooled, and, thus, there was produced non-aqueous dispersion (iv)
of this invention. In this dispersion (iv), solid content was 45%,
acid value was 32, and phosphoric acid group-containing polymer
particles had a particle size of 250 nm.
[0207] Non-Aqueous Dispersion (v) of This Invention
[0208] Into a usual reactor for the production of acrylic resin
which was equipped with stirrer, thermometer, reflux condenser,
etc., there were introduced 120 parts of xylene, 64 parts of
heptane and 55 parts of dispersion stabilizer 2, which were then
heated and stirred. When the temperature reached 100.degree. C., a
mixture of the following monomers and dispersion stabilizer 2 was
added dropwise over a period of five hours.
[0209] Methyl methacrylate 55 parts
[0210] Methyl acrylate 10 parts
[0211] 2-Hydroxyethyl acrylate 20 parts
[0212] Acid-phosphoxyhexa(oxypropylene) monomethacrylate 15
parts
[0213] Dispersion stabilizer 2) 55 parts
[0214] .alpha.,.alpha.'-Azobisisobutyronitrile 1 parts
[0215] After the dropwise addition of the above mixture was over,
the resultant mixture was kept at 100.degree. C. for further 30
minutes. Then, to said mixture, there was added dropwise a mixture
of 0.5 part of azobisdimethyl valeronitrile and 20 parts of xylene
over a period of one hour. The resultant mixture was stirred, while
kept at 100.degree. C. for two hours. Then, said mixture was
cooled, and, thus, there was produced non-aqueous dispersion (v) of
this invention. In this dispersion v), solid content was 45%, acid
value was 31, and phosphoric acid group-containing polymer
particles had a particle size of 230 nm.
[0216] 5) Clear Coatings (B)
[0217] (B-i)
[0218] In a hydrocarbon type solvent [SWASOL 1000 (trade name of a
product of Cosmo Oil Co., Ltd.)], there were mixed and dispersed 40
parts of a carboxyl group-containing acrylic resin (*5), 60 parts
of an epoxy group-containing acrylic resin (*6), 10 parts of the
non-aqueous dispersion (i) of this invention, 1 part of [TINUBIN
900] (trade name of an ultraviolet absorber of Ciba-Geigy), 2 parts
of an equal equivalent mixture of tetrabutylammonium bromide with
monobutylphosphoric acid, and 0.1 part of [BYK 300] (trade name of
a surface conditioner of BYK Chemie). The viscosity of the
resulting mixture was adjusted to 13 seconds by Ford Cup No. 4 at
20.degree. C.
[0219] (*5) Carboxyl Group-Containing Acrylic Resin
[0220] A polymer composed of 20% of methanol half ester of maleic
anhydride, 20% of 4-hydroxy n-butyl acrylate, 40% of n-butyl
acrylate and 20% of styrene, which has a number average molecular
weight of 3,500, an acid value of 86 mg KOH/g and a hydroxyl value
of 78 mg KOH/g.
[0221] (*6) Epoxy Group-Containing Acrylic Resin
[0222] A polymer composed of 30% of glycidyl methacrylate, 20% of
4-hydroxy n-butyl acrylate, 30% of n-butyl acrylate and 20% of
styrene, which has a number average molecular weight of 3,000, an
epoxy group content of 2.12 mmole/g and a hydroxyl value of 78 mg
KOH/g.
[0223] (B-ii)
[0224] In SWASOL 1000 (trade name of a hydrocarbon type solvent
produced by Cosmo Oil Co., Ltd.), there were mixed and dispersed 45
parts of a carboxyl group-containing acrylic resin (*7), 55 parts
of an epoxy group-containing acrylic resin (*6), 10 parts of the
non-aqueous dispersion (ii) of this invention, 1 part of TINUBIN
900 (trade name of an ultraviolet absorber of Ciba-Geigy), 2 parts
of an equal equivalent mixture of tetrabutylammonium bromide with
monobutylphosphoric acid, and 0.1 part of BYK 300 (trade name of a
surface conditioner of BYK Chemie). The viscosity of the resulting
mixture was adjusted to 13 seconds by Ford Cup No. 4 at 20.degree.
C.
[0225] (*7) Carboxyl Group-Containing Acrylic Resin
[0226] A polymer composed of 20% of methanol half ester of maleic
anhydride, 16% of 2-hydroxyethyl acrylate, 44% of n-butyl acrylate
and 20% of styrene, which has a number average molecular weight of
3,500, an acid value of 86 mg KOH/g and a hydroxyl value of 78 mg
KOH/g.
[0227] (B-iii)
[0228] In SWASOL 1000 (trade name of a hydrocarbon type solvent
produced by Cosmo Oil Co., Ltd.), there were mixed and dispersed 45
parts of a carboxyl group-containing acrylic resin (*7), 55 parts
of an epoxy group-containing acrylic resin (*6), 10 parts of the
non-aqueous dispersion (iii) of this invention, 1 part of a
phthalocyanine blue pigment (produced by Dainichi Seika Colour
& Chemicals MFG. CO., LTD.), 1 part of TINUBIN 900 (trade name
of an ultraviolet absorber of Ciba-Geigy), 2 parts of an equal
equivalent mixture of tetrabutylammonium bromide with
monobutylphosphoric acid, and 0.1 part of BYK 300 (trade name of a
surface conditioner of BYK Chemie). The viscosity of the resulting
mixture was adjusted to 13 seconds by Ford Cup No. 4 at 20.degree.
C.
[0229] (B-iv)
[0230] In SWASOL 1000 (trade name of a hydrocarbon type solvent
produced by Cosmo Oil Co., Ltd.), there were mixed and dispersed 45
parts of a carboxyl group-containing acrylic resin (*5), 55 parts
of an epoxy group-containing acrylic resin (*6), 10 parts of the
non-aqueous dispersion (iv) of this invention, 1 part of TINUBIN
900 (trade name of an ultraviolet absorber of Ciba-Geigy), 2 parts
of an equal equivalent mixture of tetrabutylammonium bromide with
monobutylphosphoric acid, and 0.1 part of BYK 300 (trade name of a
surface conditioner of BYK Chemie). The viscosity of the resulting
mixture was adjusted to 13 seconds by Ford Cup No. 4 at 20.degree.
C.
[0231] (B-v)
[0232] In SWASOL 1000 (trade name of a hydrocarbon type solvent
produced by Cosmo Oil Co., Ltd.), there were mixed and dispersed 45
parts of a carboxyl group-containing acrylic resin (*5), 55 parts
of an epoxy group-containing acrylic resin (*6), 10 parts of the
non-aqueous dispersion (v) of this invention, 1 part of TINUBIN 900
(trade name of an ultraviolet absorber of Ciba-Geigy), 2 parts of
an equal equivalent mixture of tetrabutylammonium bromide with
monobutylphosphoric acid, and 0.1 part of BYK 300 (trade name of a
surface conditioner of BYK Chemie). The viscosity of the resulting
mixture was adjusted to 13 seconds by Ford Cup No. 4 at 20.degree.
C.
[0233] (B-vi) (For Comparison; Without the Non-Aqueous Dispersion
of This Invention)
[0234] In SWASOL 1000 (trade name of a hydrocarbon type solvent
produced by Cosmo Oil Co., Ltd.), there were mixed and dispersed 40
parts of a carboxyl group-containing acrylic resin (*5), 60 parts
of an epoxy group-containing acrylic resin (*6), 1 part of TINUBIN
900 (trade name of an ultraviolet absorber of Ciba-Geigy), 2 parts
of an equal equivalent mixture of tetrabutylammonium bromide with
monobutylphosphoric acid, and 0.1 part of BYK 300 (trade name of a
surface conditioner of BYK Chemie). Then, the viscosity of the
resulting mixture was adjusted to 13 seconds by Ford Cup No. 4 at
20.degree. C.
[0235] 6) Base Coatings (C)
[0236] (C-i)
[0237] In a mixed organic solvent (xylene/toluene= 1/1 by weight),
there were mixed and dispersed 65 parts of a polyester resin (*8),
35 parts of a melamine resin (*9) and 10 parts of a resin
containing both phosphoric acid group and hydroxyl group (*10),
and, thus, the viscosity was adjusted to 13 seconds by Ford Cup No.
4 (20.degree. C.).
[0238] (*8) Polyester Resin
[0239] Phthalic anhydride-hexahydrophthalic anhydride type
polyester resin, having a number-average molecular weight of about
3,500, a hydroxyl value of 82 mg KOH/g and an acid value of 8 mg
KOH/g.
[0240] (9*) UBAN 28-60
[0241] Trade name of a melamine resin produced by Mitsui Toatsu
Chemicals, Inc.
[0242] (10*) Resin containing both phosphoric acid group and
hydroxyl group:
[0243] Prepared by mixing, in an organic solvent (xylene), a resin
containing phosphoric acid group, hydroxyl group and
alkoxymethylamide group, said resin having an acid value of 21 mg
KOH/g, a hydroxyl value of 72 mg KOH/g and a number average
molecular weight of 11,000, and the same resin being produced by
polymerizing 5 parts of acid-phosphoxyethyl methacrylate, 15 parts
of 2-hydroxyethyl methacrylate, 15 parts of
N-butoxymethylacrylamide, 20 parts of styrene, 15 parts of
butylmethacrylate and 30 parts of 2-ethylhexyl methacrylate in an
equal weight solvent mixture of xylene and butanol.
[0244] (C-ii)
[0245] In SWASOL 1000 (trade name of a hydrocarbon type solvent
produced by Cosmo Oil Co., Ltd.), there were mixed and dispersed 65
parts of a polyester resin (*8), 35 parts of a melamine resin (*9),
10 parts (solid) of the non-aqueous dispersion (i) of this
invention, 1 part of TINUBIN 900 (trade name of an ultraviolet
absorber of Ciba-Geigy), 2 parts of an equal equivalent mixture of
tetrabutylammonium bromide with monobutylphosphoric acid, and 0.1
part of BYK 300 (trade name of a surface conditioner of BYK
Chemie). Then, the viscosity of the resulting mixture was adjusted
to 13 seconds by Ford Cup No. 4 at 20.degree. C.
[0246] (C-iii)
[0247] In SWASOL 1000 (trade name of a hydrocarbon type solvent
produced by Cosmo Oil Co., Ltd.), there were mixed and dispersed 65
parts of a polyester resin (*8), 35 parts of a melamine resin (*9),
10 parts (solid) of the non-aqueous dispersion (ii) of this
invention, 1 part of TINUBIN 900 (trade name of an ultraviolet
absorber of Ciba-Geigy), 2 parts of an equal equivalent mixture of
tetrabutylammonium bromide with monobutylphosphoric acid, and 0.1
part of BYK 300 (trade name of a surface conditioner of BYK
Chemie). Then, the viscosity of the resulting mixture was adjusted
to 13 seconds by Ford Cup No. 4 at 20.degree. C.
[0248] (C-iv) (For Comparison)
[0249] There were mixed and dispersed, in an organic solvent
mixture (xylene/toluene=1/1 by weight), 65 parts of a polyester
resin (*8) and 35 parts of a melamine resin (*9). Then, the
viscosity of the resulting mixture was adjusted to 13 seconds by
Ford Cup No. 4 at 20.degree. C.
[0250] 7) Metallic Compositions (D)
[0251] (D-i)
[0252] A mixture of 5 parts of a leafing type aluminum flake (*3)
with 95 parts of an organic solvent (*11 ).
[0253] (*11) Organic Solvent
[0254] An equal-weight solvent mixture of toluene (surface tension:
30.9 dyn/cm) with m-xylene (surface tension: 31.23 dyn/cm)
[0255] (D-ii)
[0256] A mixture of 3 parts of a leafing type aluminum flake (*12)
with 97 parts of an organic solvent (*11).
[0257] (*12) Hi Print 60T
[0258] Trade name of a paste containing 32% of mineral spirit
produced by Toyo Aluminium K.K., each flake having a lengthwise
direction size of 4.4 .mu.m and a thickness of 0.2 .mu.m.
[0259] (D-iii) (For Comparison)
[0260] A mixture of 5 parts of a non-leafing type aluminum flake
(*4) with 95 parts of an organic solvent (*11).
2. EXAMPLES AND COMPARATIVE EXAMPLES
Examples 1 to 5 and Comparative Examples 1 to 3
[0261] Onto the uncured intermediate coating film which had been
applied on each piece to be coated, there was applied the metallic
coating (A-i) or (A-ii) so that the film might have a thickness of
5 .mu.m when cured. Then, after left to stand at room temperature
for 5 minutes, the piece was heated at 140.degree. C. for 30
minutes, and, thus, both the intermediate coating film and the
metallic coating film were cured. Subsequently, onto the metallic
coating film of each piece, there was applied one of the clear
coatings (B-i)-(B-vi) separately, so that the film of the clear
coating might have a thickness of 35 to 40 .mu.m when cured. Then,
after left to stand at room temperature for 5 minutes, each piece
was heated at 140.degree. C. for 30 minutes, and, thus, the clear
coating film was cured.
1 TABLE 1 Comparative Examples Examples 1 2 3 4 5 1 2 3 Metallic
A-i A-i A-i A-i A-i A-ii A-i A-ii coating Clear coating B-i B-ii
B-iii B-iv B-v B-i B-vi B-vi Results of Property Test Wettability
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .DELTA. .largecircle. (*1) Adhesivity
(*2) .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. X .largecircle. IV value (*3) 383 381
60 385 380 232 379 230 SV value (*4) 13.5 14 4.5 13.8 13.9 29.3 14
29.8 FF value(*5) 1.86 1.86 1.72 1.86 1.86 1.55 1.86 1.55 C* value
(*6) 1.9 1.7 83 2.2 1.5 2.9 2.2 3.1 Appearance .largecircle.
.largecircle. .circleincircle. .largecircle. .largecircle. X
.largecircle. X (*7)
[0262] Method of Property Test
[0263] (*1) Wettability
[0264] Clear coating was spray-applied on the surface of cured
metallic coating, and the degree of wetting was visually evaluated.
The mark .largecircle. shows good wetting, .DELTA. poor wetting,
and X very poor wetting.
[0265] (*2) Adhesivity
[0266] Cross-cut lines were made with a cutter so that the cutter
edge might reach the base plate through the multi-layer coating
film, and, thus, there were formed 100 squares each having a size
of 1 mm.times.1 mm. Next, Scotch tape was applied on the surface of
said squares, and, then, the tape was peeled off rapidly, and,
thus, the surface of the coated film was observed. The mark
.largecircle. shows that no square had been peeled off at all,
while X shows that 10 or more squares had been peeled off.
[0267] (*3) IV Value
[0268] Y value at the light-reception angle of 15.degree. was
measured with use of a portable goniophotometer MA 68 (produced by
X-Rite Co.). This IV value indicates the brightness of a coating
film, and shows the luminous feeling of highlight portion of
metallic coating film. This value means that, the larger it is, the
more luminous is the coating film.
[0269] (*4) SV Value
[0270] Y value at the light-reception angle of 45.degree. was
measured with use of MA 68. This SV value indicates the brightness
of coating film, and shows the frontal colour brightness of coating
film. The lower this value is, the darker is the coating film,
which means that aluminum flake is horizontally oriented to give
little diffuse light.
[0271] (*5) FF Value
[0272] Calculated from the equation:
FF=(IV-SV)/[(IV+SV)/2]
[0273] with use of the above-mentioned IV value and SV value
measured by MA 68. This FF value shows contrast between the
highlight luminance and the frontal brightness. The higher this FF
value is, the stronger is light-dark contrast feeling, which means
that a chrome plating-like finish has been achieved.
[0274] (*6) C* Value
[0275] CIE metric chroma at the light-reception angle of 15.degree.
was measured with use of MA 68. This C* value indicates chroma in
the highlight of coating film. The higher this value is, the more
vivid is the color of coating film.
[0276] (*7) Appearance
[0277] Results of visual evaluation of coating film. The mark
.largecircle. shows that a chrome plating-like finish has been
achieved. The mark .circleincircle. shows that a chrome
plating-like finish with candy tone has been achieved. The mark X
shows that not a chrome plating-like finish but an ordinary
metallic-feeling finish has been achieved.
Examples 6 to 8 and Comparative Examples 4 to 6
[0278] Onto the uncured intermediate coating which had been applied
on each piece to be coated, there was applied one of base coatings
(C-i) to (C-iv) separately. Then, on the uncured base coating,
there was applied one of metallic compositions (D-i) to (D-iii)
separately. After left to stand at room temperature for three
minutes, each piece was heated at 140.degree. C. for 30 minutes,
and, thus, each of the resultant multi-layer coatings was cured.
Subsequently, onto the metallic coating film of each piece, there
was applied one of the clear coatings (B-i), (B-ii) and (B-vi)
separately. Then, each piece was heated at 140.degree. C. for 30
minutes, and, thus, the clear coating film was cured.
[0279] Table 2 shows the results of property test of thus obtained
multi-layer coating films.
2 TABLE 2 Examples Comparative Examples 6 7 8 4 5 6 Base coating
Name c-i c-ii c-iii -- c-i c-iv Film thickness 10-15 .mu.m as a
cured film Drying Left at room temperature for 3 minutes (uncured)
Metallic composition Name D-i D-i D-ii D-i D-iii D-i Film thickness
1.3--2 .mu.m as a cured film Curing 140.degree. C. for 30 minutes
Clear coating Name B-i B-i B-ii B-vi B-i B-vi Film thickness 35-40
.mu.m as a cured film Curing 140.degree. C. for 30 minutes Results
of property Test Wettability (*1) .largecircle. .largecircle.
.largecircle. .DELTA. .largecircle. .DELTA. Adhesivity (*2)
.largecircle. .largecircle. .largecircle. X .largecircle. X IV
value (*3) 383 381 58 380 232 379 SV value (*4) 13.5 14.0 4.9 13.9
29.1 14.0 FF value (*5) 1.86 1.86 1.69 1.86 1.55 1.86 C* value (*6)
1.9 1.7 70 1.5 2.0 2.2 Appearance (*7) .largecircle. .largecircle.
.circleincircle. .largecircle. X .largecircle.
[0280] Property test was conducted in the same manner as in Table
1.
* * * * *