U.S. patent application number 11/246097 was filed with the patent office on 2006-03-09 for pigment dispersing resin.
Invention is credited to Yuko Hoshida, Isao Kamimori, Yoshio Nakajima, Akihiko Yamanouchi, Yoshiyuki Yukawa.
Application Number | 20060052514 11/246097 |
Document ID | / |
Family ID | 26602101 |
Filed Date | 2006-03-09 |
United States Patent
Application |
20060052514 |
Kind Code |
A1 |
Nakajima; Yoshio ; et
al. |
March 9, 2006 |
Pigment dispersing resin
Abstract
This invention relates to the use of a copolymer of
polymerizable unsaturated monomer containing at least one kind of
ionic functional group selected from the group consisting of
quaternary ammonium salt group and sulfonic acid group, nonionic
polymerizable unsaturated monomer having polyoxyalkylene chain, and
other ethylenically unsaturated monomer, as a pigment dispersing
resin for water-based paint or water-based ink.
Inventors: |
Nakajima; Yoshio;
(Yokohama-shi, JP) ; Yukawa; Yoshiyuki;
(Hiratsuka-shi, JP) ; Kamimori; Isao;
(Hiratsuka-shi, JP) ; Yamanouchi; Akihiko;
(Hiratsuka-shi, JP) ; Hoshida; Yuko;
(Hiratsuka-shi, JP) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
2033 K STREET N. W.
SUITE 800
WASHINGTON
DC
20006-1021
US
|
Family ID: |
26602101 |
Appl. No.: |
11/246097 |
Filed: |
October 11, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10149676 |
Jun 13, 2002 |
|
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PCT/JP01/08972 |
Oct 12, 2001 |
|
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11246097 |
Oct 11, 2005 |
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Current U.S.
Class: |
524/555 |
Current CPC
Class: |
C09D 7/45 20180101; C08F
290/06 20130101; C09D 5/027 20130101; C09B 67/0089 20130101; C09D
17/001 20130101; B41M 5/5245 20130101; C08F 290/061 20130101; C08F
290/14 20130101; C09D 11/326 20130101; C08F 290/062 20130101 |
Class at
Publication: |
524/555 |
International
Class: |
C08F 8/30 20060101
C08F008/30 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 13, 2000 |
JP |
2000-314381 |
Mar 22, 2001 |
JP |
2001-82740 |
Claims
1. A pigment dispersing resin which is a copolymer of: (A)
polymerizable unsaturated monomer containing at least one kind of
ionic functional group selected from the group consisting of
quaternary ammonium salt group and sulfonic acid group; (B)
nonionic polymerizable unsaturated monomer having polyoxyalkylene
chain; and (C) other ethylenically unsaturated monomer.
2. A pigment dispersing resin of claim 1 wherein the ionic
functional group-containing polymerizable unsaturated monomer (A)
is selected from the group consisting of 2-(methacryloyloxy)ethyl
trimethylammonium chloride, 2-(methacryloyloxy)ethyl
trimethylammonium bromide, (meth)acryloylaminopropyl
trimethylammonium chloride, (meth)acryloylaminopropyl
trimethylammonium bromide, tetrabutylammonium(meth)acrylate,
trimethylbenzylammonium (meth)acrylate, 2-(methacryloyloxy)ethyl
trimethylammonium dimethylphosphate,
2-acrylamide-2-methylpropanesulfonic acid and
2-sulfoethyl(meth)acrylate.
3. A pigment dispersing resin of claim 1 wherein the ionic
functional group-containing polymerizable unsaturated monomer (A)
is selected from the group consisting of
2-(methacryloyloxy)ethyltrimethylammonium chloride and
2-acrylamide-2-methylpropanesulfonic acid.
4. A pigment dispersing resin of claim 1 wherein the ionic
functional group-containing polymerizable unsaturated monomer (A)
comprises a combination of quaternary ammonium salt
group-containing polymerizable unsaturated monomer and tertiary
amino group-containing polymerizable unsaturated monomer.
5. A pigment dispersing resin of claim 4 wherein tertiary amino
group-containing polymerizable unsaturated monomer is selected from
the group consisting of N,N-dialkylaminoalkyl (meth)acrylate and
N,N-dialkylaminoalkyl (meth)acrylamide.
6. A pigment dispersing resin of claim 4 wherein the ionic
functional group-containing polymerizable unsaturated monomer (A)
comprises a combination of
2-(methacryloyloxy)ethyltrimethylammonium chloride and either
N,N-dimethylaminoethyl (meth)acrylate or N,N-diethylaminoethyl
(meth)acrylate.
7. A pigment dispersing resin of claim 1 wherein nonionic
polymerizable unsaturated monomer (B) is compound of the following
formula (1): ##STR2## in which R.sub.1 stands for hydrogen or
CH.sub.3, R.sub.2 stands for hydrogen or alkyl group having one to
four carbon atoms, m is an integer of 4-60, and n is an integer of
2 or 3, and wherein oxyalkylene units (C.sub.nH.sub.2nO) in the
number of m may be the same or different from each other.
8. A pigment dispersing resin of claim 1 wherein nonionic
polymerizable unsaturated monomer (B) is selected from the group
consisting of polyethylene glycol (meth)acrylate and polypropylene
glycol (meth) acrylate.
9. A pigment dispersing resin of claim 1 wherein other
ethylenically unsaturated monomer (C) contains a hydroxyl
group-containing polymerizable unsaturated monomer at least as a
part of its component.
10. A pigment dispersing resin of claim 1 wherein other
ethylenically unsaturated monomer (C) contains a carboxyl
group-containing polymerizable unsaturated monomer at least as a
part of its component.
11. A pigment dispersing resin of claim 1 wherein the copolymer has
a weight average molecular weight within a range of 500 to 100,000.
Description
[0001] This is a divisional of U.S. application Ser. No.
10/149,676, filed Jun. 13, 2002 which is a 371 of PCT/JP01/08972,
filed Oct. 12, 2001.
TECHNICAL FIELD
[0002] This invention relates to a pigment dispersing resin which
is suitably used for water-based paint or water-based ink, and to
aqueous pigment dispersions containing said pigment dispersing
resin which are especially suitable as water-based top-coating
paint for automobile and as ink-jet ink.
BACKGROUND ART
[0003] As top-coating paint for automotive finish, there have
heretofore been used those of solvent-based type in which a base
resin (base polymer) component such as acrylic resin, polyester
resin or alkyd resin having such functional groups as hydroxyl
group and carboxyl group is used together with a curing agent such
as amino resin, optionally-blocked polyisocyanate compound and
epoxy compound.
[0004] For the protection of terrestrial environment, paint of low
volatile organic matter content (VOC) has been demanded in these
years. In the field of paint for automotive finish, colored base
coating paint in particular has high discharge of VOC. It has
therefore been strongly required to switch colored base coating
paint to water-based type. It is now expected that, in future,
solvent-based coating type will be replaced with water-based
coating type.
[0005] Problems incidental to the switching of colored base coating
paint to water-based type are, for example: (1) pigment dispersing
resin blended in water-based paint is incompatible with the binder
component in water-based paint; (2) pigment dispersing resin or
dispersant fails to uniformly disperse the pigment, and invites
flocculation or agglomeration of pigment; and (3) pigment
dispersing resin or dispersant in the water-based paint composition
fails to cure under baking, and invites the degradation of coating
film performance.
[0006] Pigments which are used for colored base coating paint
generally have hydrophobic surfaces, and are difficult to be wetted
with water, while pigment dispersing resins which have
conventionally been used for solvent-based colored paint have low
solubility in water, and are inferior in dispersing stability in
aqueous media. Hence, it is important in designing a pigment
dispersing resin for water-based paint to secure satisfactory
levels of both wettability of pigment and dispersing stability of
pigment dispersing resin in an aqueous medium.
[0007] Besides, pigment is now being substituting for dye as a
color material for ink, in particular ink-jet ink, from the
viewpoint of water resistance and weatherability. However,
water-based pigment ink is still unsatisfactory in the print
density of printed image. Besides, pigment has a problem that, when
its dispersion stability is low, clogging occurs in head when it is
used for ink-jet ink. Hence, high-level pigment wettability and
pigment dispersion stability are required of said water-based
pigment ink.
[0008] Low viscosity and low molecular weight of pigment dispersing
resin are considered advantageous for wetting property of pigment;
and easy formation of steric repelling layer on the pigment
surfaces or good solubility of the pigment dispersing resin in the
continuous phase (aqueous medium) are considered advantageous for
the dispersing stability. Both the pigment-wetting property and the
dispersing stability of the pigment dispersing resin are considered
to participate in wetting of the pigment surface with the pigment
dispersing resin (a resin having a group capable of forming weak
flocculation in aqueous system such as alkyl-group is effective)
and in adsorption onto the pigment, which are attributable to the
interaction between hydrophobic part on the pigment surface and
that of pigment dispersing resin.
[0009] Past development of pigment dispersing resins or assistant
for water-based paint or water-based ink has been advanced based on
the foregoing viewpoints. For instance, Japanese Patent Application
Laid-Open No. 154328/1975 proposed use of a straight chain anionic
polymer containing acidic functional groups which is obtained
through polymerization of a monomer mixture containing as a part of
its monomer components an acidic functional group-containing,
polymerizable unsaturated monomer such as (meth)acrylic acid, as
the pigment dispersing resin. Said polymer, however, exhibits high
solubility in aqueous media and hence is unsatisfactory in respect
of dispersion stability of pigment dispersions. Furthermore,
pigment dispersions formed with the use of said polymer show
excessively high viscosity and are subject to a drawback of
difficult handling.
[0010] Japanese Patent Application Laid-Open No. 182304/1989,
Japanese Patent Application Laid-Open No. 316240/1995 and Japanese
Patent Application Laid-Open No. 502097/1998 disclosed, as the
pigment dispersing resin, a graft copolymer obtained through
copolymerization of carboxyl-containing macromonomers. Said graft
copolymer excels in pigment dispersing stability because its trunk
portion is hydrophobic and the branch portion is hydrophilic
whereas pigment dispersions formed with the use of said copolymer
show high viscosity, and the graft copolymer is far from being
satisfactory in view of the increasing demand for pigment
dispersions having high pigment concentration to save cost and to
reduce VOC.
[0011] Japanese Patent Application Laid-Open No. 255728/1997,
Japanese Patent Application Laid-Open No. 267034/1997 and Japanese
Patent Publication No. 19201/1996 disclose an idea of using, as
pigment dispersing agent, a nonionic surfactant having
polyoxyalkylene chain. Although capable of existing stably in
water-based pigment dispersions, said surfactant is unsatisfactory
in adsorption to pigment, and is in particular poor in let-down
stability, and, moreover, inferior in the appearance of resultant
coating film.
[0012] On the other hand, top-coating paint for automotive finish
are now required to have not only film performance such as high
durability, acid resistance, washability (scratch resistance) and
chipping resistance, but also still better appearance of coating
film in sharpness, transparency, color development, and the like,
than before.
[0013] An object of the present invention is to provide pigment
dispersing resins which excel in wetting property and dispersing
stability even at high pigment concentration, and which can provide
aqueous pigment dispersions having low viscosity, excellent in
color developing property and giving a coating film with good
appearance.
[0014] A further object of the present invention is to provide a
water-based pigment dispersion which has low viscosity and which
excels in color-developing property.
[0015] Another object of the invention is to provide a water-based
paint which excels in curability and which is capable of forming a
painted film of splendid finish appearance in sharpness,
transparency and color-developing property and weatherability.
[0016] Another object of the invention is to provide a water-based
ink composition which excels in sharpness, transparency,
color-developing property and weatherability.
[0017] Other objects and characteristics of the invention will
become apparent from the following descriptions.
DISCLOSURE OF INVENTION
[0018] After assiduous study to achieve the above-mentioned
objectives, the inventors of this invention have found out that a
pigment dispersing resin which is obtained by copolymerizing a
monomer having hydrophilic functional group which is a certain kind
of ionic group, a nonionic hydrophilic monomer having
polyoxyethylene chain and the like, and other ethylenically
unsaturated monomers in the presence of radical polymerization
initiator is quite suitable as a pigment dispersing resin for
water-based paint or water-based ink.
[0019] This invention provides a pigment dispersing resin which is
a copolymer of: [0020] (A) polymerizable unsaturated monomer
containing at least one kind of ionic functional group selected
from the group consisting of quaternary ammonium base and sulfonic
acid group; [0021] (B) nonionic polymerizable unsaturated monomer
having polyoxyalkylene chain; and [0022] (C) other ethylenically
unsaturated monomer.
[0023] This invention also provides an aqueous pigment dispersion
which comprises the above-mentioned pigment dispersing resin,
pigment, aqueous medium and, if necessary, dispersion adjuvant as
well.
[0024] This invention further provides a water-based paint
composition and a water-based ink composition each of which
comprises the above-mentioned aqueous pigment dispersion.
[0025] The following is a further detailed explanation about
pigment dispersing resin, aqueous pigment dispersion, water-based
paint composition and water-based ink composition of this
invention.
Pigment Dispersing Resin
[0026] The pigment dispersing resin which is provided by this
invention is a copolymer of (A) an ionic functional
group-containing polymerizable unsaturated monomer, (B) a nonionic
polymerizable unsaturated monomer, and (C) other ethylenically
unsaturated monomer, as follows.
Ionic Functional Group-Containing Polymerizable Unsaturated Monomer
(A):
[0027] Monomer (A) is a monomeric component by which to introduce a
specific ionic functional group into a pigment dispersing resin.
For this monomer (A), there is employed a polymerizable unsaturated
monomer having at least one kind of ionic functional group which is
selected from quaternary ammonium salt group and sulfonic acid
group.
[0028] Specific examples of monomer (A) include quaternary ammonium
salt-containing polymerizable unsaturated monomers like:
(meth)acryloyloxyalkyl trialkylammonium salt groups such as
2-(methacryloyloxy)ethyl trimethylammonium chloride,
2-(methacryloyloxy)ethyl trimethylammonium bromide and
2-(methacryloyloxy)ethyl trimethylammonium dimethylphosphate;
(meth)acryloylaminoalkyltrialkyl ammonium salt groups such as
(meth)acryloylaminopropyl trimethylammonium chloride and
(meth)acryloylaminopropyl trimethylammonium bromide;
tetraalkyl(meth)acrylate such as tetrabutylammonium(meth)acrylate;
and trialkylbenzylammonium (meth)acrylate such as
trimethylbenzylammonium (meth)acrylate; and sulfonic acid
group-containing polymerizable unsaturated monomers like:
(meth)acrylamide-alkanesulfonic acid such as
2-acrylamide-2-methylpropanesulfonic acid; and
sulfoalkyl(meth)acrylate such as 2-sulfoethyl(meth)acrylate. These
monomers may be used either singly or in combination of two or
more. Among the above-mentioned monomers,
2-(methacryloyloxy)ethyltrimethylammonium chloride and
2-acrylamide-2-methylpropanesulfonic acid are particularly suitable
as polymerizable unsaturated monomer (A).
[0029] The above-mentioned quaternary ammonium salt
group-containing polymerizable unsaturated monomer may be used
together with tertiary amino group-containing polymerizable
unsaturated monomer. For example,
2-(methacryloyloxy)ethyltrimethylammonium chloride is preferably
used together with N,N-dimethylaminoethyl(meth)acrylate and/or
N,N-diethylaminoethyl(meth)acrylate, which can broaden the range of
pigment to which the pigment dispersing resin of this invention is
applicable.
[0030] Examples of tertiary amino group-containing polymerizable
unsaturated monomer which can be used together include
N,N-dialkylaminoalkyl (meth)acrylates such as
N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl
(meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate,
N,N-di-t-butylaminoethyl (meth)acrylate and N,N-dimethylaminobutyl
(meth)acrylate; and N,N-dialkylaminoalkyl (meth)acrylamides such as
N,N-dimethylaminoethyl (meth)acrylamide, N,N-diethylaminoethyl
(meth)acrylamide and N,N-dimethylaminopropyl (meth)acrylamide;
[0031] In the case of said combined use, the weight ratio of (a)
quaternary ammonium salt group-containing polymerizable unsaturated
monomer to (b) tertiary amino group-containing polymerizable
unsaturated monomer is usually in a range of 10/1 to 1/20,
especially 5/1 to 1/10.
[0032] When quaternary ammonium salt group-containing polymerizable
unsaturated monomer is used as monomer (A), quaternary ammonium
salt group which is introduced into resin acts effectively
especially for the sake of dispersibility of acidic pigment or
neutral pigment. When, on the other hand, sulfonic acid
group-containing polymerizable unsaturated monomer is used as
monomer (A), sulfonic group which is introduced into resin acts
effectively especially for the sake of dispersibility of basic
pigment.
Nonionic Polymerizable Unsaturated Monomer (B) Containing
Polyoxyalkylene Chain:
[0033] Monomer (B) is a monomeric component which gives
hydrophilicity to the formed copolymer, and which contains
polyoxyalkylene chain and polymerizable unsaturated monomer in
molecule. Examples of said polyoxyalkylene chain include
polyoxyethylene chain, polyoxypropylene chain and
polyoxyethylene-polyoxypropylene block chain.
[0034] Polyoxyalkylene chain has preferably a molecular weight in a
range of 200 to 3,000, in particular 300 to 2,500.
[0035] Typical example of monomer (B) is represented by compounds
of the following formula (1): ##STR1##
[0036] in which
[0037] R.sub.1 stands for hydrogen or CH.sub.3,
[0038] R.sub.2 stands for hydrogen or C.sub.1 to C.sub.4 alkyl
group,
[0039] m is an integer of 4-60, in particular 6-50, and
[0040] n is an integer of 2-3, preferably 2, and
[0041] oxyalkylene units (C.sub.nH.sub.2nO) in the number of m may
be the same or different from each other.
[0042] Specific examples of such monomer (B) are as follows:
tetraethylene glycol (meth)acrylate, methoxytetraethylene glycol
(meth)acrylate, ethoxytetraethylene glycol (meth)acrylate,
n-butoxytetraethylene glycol (meth)acrylate, tetrapropylene glycol
(meth)acrylate, methoxytetrapropylene glycol (meth)acrylate,
ethoxytetrapropylene glycol (meth)acrylate, n-butoxytetrapropylene
glycol (meth)acrylate, polyethylene glycol (meth)acrylate,
polypropylene glycol (meth)acrylate, methoxypolyethylene glycol
(meth)acrylate and ethoxypolyethylene glycol (meth)acrylate, among
which polyethylene glycol (meth)acrylate and polypropylene glycol
(meth)acrylate are particularly suitable.
[0043] These monomers may be used either singly or in combination
of two or more.
Other Ethylenically Unsaturated Monomer (C):
[0044] Other ethylenically unsaturated monomer (C) is a
polymerizable unsaturated monomer other than the above monomers (A)
and (B), which is copolymerizable with said monomers (A) and (B),
and is suitably selected according to properties required of
pigment dispersing resins.
[0045] Concrete examples of such monomer (C) include C.sub.1 to
C.sub.24 straight chain- or cyclic-alkyl (meth)acrylate monomer
such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl
(meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate,
isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl
(meth)acrylate, n-octyl (meth)acrylate, lauryl (meth)acrylate,
stearyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl
(meth)acrylate and tridecyl (meth)acrylate; hydroxyl
group-containing polymerizable unsaturated monomer (typically
hydroxyalkyl (meth)acrylate monomer) such as 2-hydroxyethyl
(meth)acrylate, hydroxypropyl (meth)acrylate and hydroxybutyl
(meth)acrylate; carboxyl group-containing polymerizable unsaturated
monomer such as methacrylic acid and acrylic acid; acrylamide and
(meth)acrylamide; oxetane ring-containing (meth)acrylates such as
3-ethyl-3-(meth)acryloyloxymethyl oxetane,
3-methyl-3-(meth)acryloyloxymethyl oxetane and
3-butyl-3-(meth)acryloyloxymethyl oxetane; aromatic vinyl compounds
such as styrene, .alpha.-methyl styrene and vinyl toluene;
(meth)acrylonitrile; and vinyl acetate. These polymerizable
unsaturated monomers may be used either singly or in combination of
two or more.
[0046] The pigment dispersing resin which is provided by the
present invention is used, for example, for the preparation of
colored water-based base coating paint. Hence, the pigment
dispersing resin of the present invention desirably reacts with
curing agent component, e.g., amino resins or optionally-blocked
polyisocyanate compounds, to be incorporated into the crosslinked
paint film, for the sake of favorable paint film performance.
Therefore, monomer (C) desirably contains a hydroxyl
group-containing polymerizable unsaturated monomer at least as a
part of its component.
[0047] When used for water-based ink, monomer (C) desirably
contains a hydroxyl group-containing polymerizable unsaturated
monomer at least as a part of its component from a viewpoint of
wettability to printed surface, spreadability of ink and reactivity
with the above-mentioned curing agent component, and the like.
[0048] Specific examples of such hydroxyl group-containing
polymerizable unsaturated monomer include monoesters between
polyhydric alcohols and (meth)acrylic acid such as 2-hydroxyethyl
(meth)acrylate, hydroxypropyl (meth)acrylate, 2,3-dihydroxybutyl
(meth)acrylate, 4-hydroxybutyl (meth)acrylate, polyethylene glycol
mono(meth)acrylate and the like; and compounds formed by
ring-opening polymerization of said monoesters of polyhydric
alcohols and (meth)acrylic acid, with .epsilon.-caprolactone. In
particular, 4-hydroxybutyl (meth)acrylate, polyethylene glycol
mono(meth)acrylate and compounds formed by ring-opening
polymerization of said monoesters of polyhydric alcohols and
acrylic or methacrylic acid, with .epsilon.-caprolactone, show
favorable reactivity. The above-recited compounds may be used
either singly or in combination of two or more.
[0049] The use rate of the hydroxyl group-containing polymerizable
unsaturated monomers is normally 3-30% by weight, in particular
5-25% by weight, based on the total weight of the monomers (A), (B)
and (C).
[0050] The pigment dispersing resin of this invention is intended
to be used chiefly for aqueous system. With a view to keeping the
water dispersibility of said resin, there may be used, in addition
to the above-mentioned monomer (B), carboxyl group-containing
polymerizable unsaturated monomer at least as a part of the
above-mentioned other ethylenically unsaturated monomer (C), if
necessary.
Pigment Dispersing Resin
[0051] The pigment dispersing resin of this invention is produced
by the copolymerization of ionic functional group-containing
polymerizable unsaturated monomer (A), nonionic polymerizable
unsaturated monomer (B) and other ethylenically unsaturated monomer
(C). The proportion of monomers (A), (B) and (C) in
copolymerization is not strictly restricted, but may be varied
depending on the physical property required of formed copolymer,
and the like. Generally, however, the proportion may be set in the
following range on the basis of the total weight of monomers (A),
(B) and (C): [0052] Monomer (A): 1 to 15% by weight, preferably 2
to 10% by weight, much more desirably 3 to 8% by weight; [0053]
Monomer (B): 5 to 40% by weight, preferably 7 to 35% by weight,
much more desirably 10 to 30% by weight; [0054] Monomer (C): 45 to
94% by weight, preferably 55 to 91% by weight, much more desirably
62 to 87% by weight.
[0055] The copolymerization of monomers (A), (B) and (C) may be
conducted by any known method, for instance, by solution
polymerization in an organic solvent, emulsion polymerization in
water, or the like, among which solution polymerization is
suitable. In an example of copolymerization by solution
polymerization, a mixture of the above-mentioned monomers (A), (B)
and (C) and a radical polymerization initiator is dissolved or
dispersed in an organic solvent, and heated for polymerization at a
temperature of about 80.degree. C. to about 200.degree. C. with
stirring for 1 to 10 hours.
[0056] Examples of organic solvent which is usable for
copolymerization include hydrocarbon solvents such as heptane,
toluene, xylene, octane and mineral spirit; ester solvents such as
ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycol
monomethylether acetate and diethylene glycol monobutylether
acetate; ketone solvents such as methyl ethyl ketone, methyl
isobutyl ketone, diisobutyl ketone and cyclohexanone; alcohol
solvents such as methanol, ethanol, isopropanol, n-butanol,
sec-butanol and isobutanol; ether solvents such as n-butyl ether,
dioxane, ethylene glycol monomethyl ether and ethylene glycol
monoethyl ether and the like; and aromatic petroleum solvents such
as Swasol.TM. 310, Swasol.TM. 1000 and Swasol.TM. 1500 of Cosmo Oil
Co., Ltd. These organic solvents can be used either singly or in
combination of two or more. At the time of (co-)polymerization, the
organic solvent is normally used in an amount not more than 400
parts by weight based on 100 parts by weight of the monomer
components to be (co-)polymerized.
[0057] Examples of the above-mentioned radical polymerization
initiator include organic peroxide polymerization initiators like
ketone peroxides such as cyclohexanone peroxide,
3,3,5-trimethylcyclohexanone peroxide and methylcyclohexanone
peroxide; peroxyketals such as
1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane,
1,1-bis(tert-butylperoxy)cyclohexane and
n-butyl-4,4-bis(tert-butylperoxy)valerate; hydroperoxides such as
cumene hydroperoxide and 2,5-dimethylhexane-2,5-dihydroperoxide;
dialkylperoxides such as
1,3-bis(tert-butylperoxy-m-isopropyl)benzene,
2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, diisopropylbenzene
peroxide and tert-butylcumyl peroxide; diacyl peroxides such as
decanoyl peroxide, lauroyl peroxide, benzoyl peroxide and
2,4-dichlorobenzoyl peroxide; peroxycarbonates such as
bis(tert-butylcyclohexyl)peroxydicarbonate; and peroxy esters such
as tert-butylperoxybenzoate and
2,5-dimethyl-2,5-di(benzoylperoxy)hexane; and azo polymerization
initiators like 2,2'-azobisisobutyronitrile,
1,1-azobis(cyclohexane-1-carbonitrile),
azocumene-2,2'-azobismethylvaleronitrile and
4,4'-azobis(4-cyanovalerianic acid). The use rate of these
polymerization initiators is not critical. Normally, however, it is
desirably within a range of 0.1-15 parts by weight, in particular
0.3-10 parts by weight, per 100 parts by weight of the total of the
monomers to be copolymerized.
[0058] In the above-mentioned polymerization reaction, the method
of addition of the monomeric components or the polymerization
initiator is not critical. The polymerization initiator is,
however, conveniently added dropwise plural times by portions over
the time spun from the initial stage of polymerization to the
advanced stage, rather than added in a lump sum at the initial
stage, for the sake of effective temperature control during the
polymerization reaction and of the prevention of undesirable
cross-linked product such as gel from formed.
[0059] The molecular weight of thus produced copolymer is not in
particular restricted. Preferably, however, the weight average
molecular weight of copolymer is within a range of 500 to 100,000,
in particular 1,000 to 70,000, especially 3,000 to 50,000, from a
viewpoint of aqueous dispersion stability, pigment dispersibility,
viscosity, VOC and color number (degree of pigmentation).
[0060] The pigment dispersing resin of this invention which
comprises copolymer produced in the afore-mentioned manner is used
for the preparation of water-based pigment dispersion. The pigment
dispersion resin is therefore required to have both wettability
with regard to pigment and pigment dispersion stability. Monomer
(A) component which constitutes the pigment dispersing resin of
this invention is capable of improving the adsorption of pigment
dispersing resin to pigment, and thus acts advantageously for the
improvement both in wettability with regard to pigment and in the
dispersion stability of resin. Monomer (B) component which
constitutes the pigment dispersing resin of this invention
contributes to the improvement of pigment dispersing resin in the
solubility in continuous phase (aqueous medium), and acts
advantageously in particular for the improvement of pigment
dispersing resin in dispersion stability. Furthermore,
copolymerization with use of tertiary amino group-containing
polymerizable unsaturated monomer in combination with monomer (A)
provides a pigment dispersing resin which has remarkably improved
capability to disperse black (carbon black) pigment which is said
to be especially difficult to be dispersed.
[0061] Hence, the pigment dispersing resin of this invention is
quite useful for the preparation of water-based pigment dispersion
together with pigment and aqueous medium.
Water-Based Pigment Dispersion
[0062] The water-based pigment dispersion of this invention can be
prepared by blending, with the afore-mentioned pigment dispersing
resin of the invention, pigment, aqueous medium and, as
circumstances may demand, other pigment dispersing resins,
dispersing agent, basic neutralizer and other additives as
well.
[0063] Examples of pigment include: bright pigments such as
aluminum powder, copper powder, nickel powder, stainless steel
powder, chromium powder, micaceous iron oxide, titanium
dioxide-coated mica powder, iron oxide-coated mica powder and
bright graphite; organic red pigments such as Pink EB, azo- and
quinacridone-derived pigments; organic blue pigments such as cyanin
blue and cyanin green; organic yellow pigments such as
benzimidazolone-, isoindolin- and quinophthalone-derived pigments;
inorganic colored pigments such as titanium white, titanium yellow,
iron red, carbon black, chrome yellow, iron oxide and various
calcined pigments. Also extender pigment may be included.
[0064] These pigments may be subjected to any known treatment such
as acid base treatment, coupling agent treatment or
oxidation/reduction treatment.
[0065] Among the above pigments, concrete examples of pigments
which are used in particular for ink-jet ink include black pigment
like Raven 7000, Raven 5750, Raven 5250, Raven 5000 ULTRAII, Raven
3500, Raven 2000, Raven 1500, Raven 1250, Raven 1200, Raven 1190
ULTRAII, Raven 1170, Raven 1255, Raven 1080 and Raven 1060 (which
are manufactured by Columbian Carbon Co.); Regal400R, Regal330R,
Regal660R, Mogul L, Black Pearls L, Monarch 700, Monarch 800,
Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300
and Monarch 1400 (which are manufactured by Cabot Co.); Color Black
FW1, Color Black FW2, Color Black FW2V, Color Black 18, Color Black
FW200, Color Black S150, Color Black S160, Color Black S170,
Printex35, PrintexU, PrintexV, Printex140U, Printex140V, Special
Black 6, Special Black 5, Special Black 4A and Special Black 4
(which are manufactured by Degussa Co.); No. 25, No. 33, No. 40,
No. 47, No. 52, No. 900, No. 2300, MCF-88, MA600, MA7, MA8 and
MA100 (which are manufactured by Mitsubishi Chemical Corporation);
cyanic color pigment like C.I. Pigment Blue-1, C.I. Pigment Blue-2,
C.I. Pigment Blue-3, C.I. Pigment Blue-15, C.I. Pigment Blue-15:1,
C.I. Pigment Blue-15:3, C.I. Pigment Blue-15:34, C.I. Pigment
Blue-16, C.I. Pigment Blue-22 and C.I. Pigment Blue-60; magenta
color pigment like C.I. Pigment Red-5, C.I. Pigment Red-7, C.I.
Pigment Red-12, C.I. Pigment Red-48, C.I. Pigment Red-48:1, C.I.
Pigment Red-57, C.I. Pigment Red-112, C.I. Pigment Red-122, C.I.
Pigment Red-123, C.I. Pigment Red-146, C.I. Pigment Red-168, C.I.
Pigment Red-184 and C.I. Pigment Red-202; and yellow color pigment
like C.I. Pigment Yellow-1, C.I. Pigment Yellow-2, C.I. Pigment
Yellow-3, C.I. Pigment Yellow-12, C.I. Pigment Yellow-13, C.I.
Pigment Yellow-14, C.I. Pigment Yellow-16, C.I. Pigment Yellow-17,
C.I. Pigment Yellow-73, C.I. Pigment Yellow-74, C.I. Pigment
Yellow-75, C.I. Pigment Yellow-83, C.I. Pigment Yellow-93, C.I.
Pigment Yellow-95, C.I. Pigment Yellow-97, C.I. Pigment Yellow-98,
C.I. Pigment Yellow-114, C.I. Pigment Yellow-128, C.I. Pigment
Yellow-129, C.I. Pigment Yellow-151 and C.I. Pigment Yellow-154.
These are only examples, and not restrictive at all.
[0066] Blend ratios of these pigments are not subject to specific
limitations. Normally, however, they are within a range of
10-3,000, preferably 15-2,000, inter alia 15-1,500 parts by weight,
per 100 parts by weight of a pigment dispersing resin of the
present invention in consideration of pigment dispersing ability,
dispersion stability and color developing property of resulting
pigment dispersions.
[0067] Examples of useful aqueous medium include water and
water-organic solvent mixtures formed by dissolving organic solvent
such as water-soluble organic solvent in water. Useful organic
solvent in such mixtures include, for example, water-soluble
organic solvents such as methyl alcohol, ethyl alcohol, isopropyl
alcohol, propylpropylene glycol, butyl cellosolve, propylene glycol
monomethyl ether and 3-methyl-3-methoxybutanol; and
water-hardly-soluble or water-insoluble organic solvents such as
xylene, toluene, cyclohexanone, hexane and pentane. These organic
solvents may be used either singly or as a mixture of two or more.
Water-insoluble organic solvent may be concurrently used with
water-soluble organic solvent, in minor quantities. The mixing
ratio of water and organic solvent is not critical. It is
desirable, however, that the organic solvent content of the mixture
does not exceed 50%, in particular 35%, by weight. The blend ratio
of the aqueous medium is not critical. It is desirable, however,
that the ratio is within a range of 50-5,000, preferably 100-3,000,
inter alia 100-2,000, parts by weight per 100 parts by weight of a
pigment dispersing resin or resins of the present invention in
respect of viscosity in the occasion of dispersing the pigment,
pigment dispersing ability, dispersion stability and production
efficiency.
[0068] Examples of other pigment dispersing resins which are used
where necessary include acryilc resin which is produced by the
copolymerization of carboxylic group-containing polymerizable
unsaturated monomer such as (meth)acrylic acid with hydroxyl
group-containing polymerizable unsaturated monomer such as
2-hydroxyethyl (meth)acrylate and other polymerizable unsaturated
monomer in the presence of radical polymerization initiator. Such
an acrylic resin preferably has a weight average molecular weight
within a range of about 2,000 to 150,000, in particular 5,000 to
100,000, and an acid value in a range of 5 to 150, especially 15 to
80, and a hydroxyl value in a range of 10 to 160, in particular 30
to 120. Other pigment dispersing resins also include polyester
resin which is produced by condensation reaction between polyhydric
alcohol such as ethylene glycol, butylene glycol, 1,6-hexane diol,
trimethylol propane and pentaerythritol and polyvalent carboxylic
acid component such as adipic acid, isophthalic acid, terephthalic
acid, phthalic anhydride, hexahydrophthalic anhydride and
trimellitic acid anhydride. Such a polyester resin preferably has a
weight average molecular weight within a range of about 1,000 to
100,000, in particular 1,500 to 70,000, and an acid value in a
range of 5 to 150, especially 10 to 75, and a hydroxyl value in a
range of 10 to 160, in particular 30 to 120.
[0069] In the process of production of water-based pigment
dispersion of this invention, pigment and pigment dispersing resin
of this invention are usually diluted with other pigment dispersing
resin after dispersed in aqueous medium. Owing to this dilution,
the resultant dispersion has stability as enamel or long-term
storage stability, or becomes readily miscible with binder
component of paint etc.
[0070] As for the proportion of the pigment dispersing resin (I) of
this invention and other pigment dispersing resin (II), resin (II)
is suitably used in an amount of 5 to 300 parts by weight, in
particular 20 to 150 parts by weight, per 100 parts by weight of
resin (I).
[0071] As examples of dispersing agent to be used where necessary,
Disperbyk.TM. 184 or 190 (BYK-Chemie Co.) may be named. Other
usable additives include anti-foaming agent, antiseptic,
rust-proofing agent and plasticizing agent. It is desirable that
blend ratio of any of these additives does not exceed 50 parts by
weight per 100 parts by weight of the pigment dispersing resin of
the present invention in respect of pigment dispersing ability of
the resin, stability of the pigment paste, let-down stability or
coating film performance.
[0072] When other pigment dispersing resins have carboxyl groups,
basic neutralizer is used to neutralize the carboxyl groups and to
make said other pigment dispersing resins water-soluble or
water-dispersible. Specific examples of such a basic neutralizer
include inorganic bases such as ammonium hydroxide, sodium
hydroxide and potassium hydroxide; and amines such as aminomethyl
propanol, aminoethylpropanol, dimethylethanolamine, triethylamine,
diethylethanolamine, dimethylaminopropanol and aminomethylpropanol.
Such a basic neutralizer should be used in a sufficient rate to
render said other pigment dispersing resins water-soluble or
water-dispersible. Normally, therefore, basic neutralizer is used
at a rate sufficient to make the neutralization equivalent of
carboxyl group in said other pigment dispersing resins 0.3-1.5,
preferably 0.4-1.3.
[0073] In this invention, no basic neutralizer is desirably used
when pigment is to be dispersed with use of the pigment dispersing
resin of this invention. If a basic neutralizer is used, pigment
adsorbs the basic neutralizer before the pigment dispersing resin
of this invention is adsorbed on the pigment, with the result that
dispersibility may possibly be damaged. When, on the other hand,
pigment is dispersed by the pigment dispersing resin of this
invention and is then diluted with other pigment dispersing resins,
neutralization with basic neutralizer is desirable.
[0074] Water-based pigment dispersions can be formulated by
homogeneously mixing and dispersing the above-described components
with a dispersing machine such as paint shaker, Scandix, LMZ mill,
DCP pearl mill and the like.
Water-Based Paint Compositions
[0075] Thus prepared water-based pigment dispersion can be blended
with binder resin for paint and suitably with other additives such
as aqueous medium, fine polymer particles, curing catalyst, basic
neutralizer, ultraviolet absorber, ultraviolet stabilizer, paint
film surface regulating agent, antioxidant, flow property
regulator, silane coupling agent and the like, and stably dispersed
in aqueous medium to provide a water-based paint composition.
[0076] Useful paint binder resins include combination of base
resins which are normally used in the field of water-soluble or
water-dispersible paint, with curing agent. Examples of such base
resin include hydroxyl group-containing acrylic resin, hydroxyl
group-containing polyester resin, epoxy group-containing copolymer
resin and carboxyl group-containing high acid value resin. As
examples of useful curing agent, amino resins and
optionally-blocked polyisocyanate compounds can be named, which can
be used either singly or in combination.
[0077] As said hydroxyl group-containing acrylic resin, copolymers
having a weight-average molecular weight within a range of from
about 2,000 to about 100,000, in particular, from 5,000 to 50,000,
which are obtained by copolymerization of a hydroxyl
group-containing polymerizable unsaturated monomer such as
2-hydroxyethyl (meth)acrylate with other polymerizable unsaturated
monomer or monomers in the presence of a radical polymerization
initiator are preferred.
[0078] As hydroxyl group-containing polyester resin, those having a
weight-average molecular weight within a range of from about 1,000
to about 100,000, in particular, from 1,500 to 70,000, which are
obtained by condensation reaction between polyhydric alcohols such
as ethylene glycol, butylene glycol, 1,6-hexanediol,
trimethylolpropane and pentaerythritol, and polyvalent carboxylic
acids such as adipic acid, isophthalic acid, terephthalic acid,
phthalic anhydride, hexahydrophthalic anhydride and trimellitic
anhydride are preferred.
[0079] As amino resins which are used as curing agent, melamine
resins are used in general. In particular, methylolmelamine resins
and melamine resins whose methylol groups are at least partially
etherified with C.sub.1-C.sub.4 monohydric alcohols are suitable.
While it is preferred that they be water-soluble or
water-dispersible, water-insoluble ones can also be used.
[0080] As commercially available melamine resins useful for the
above purpose, the following may be named for example: butyl
etherified melamine resins such as U-Van.TM. 20SE-60 and 225
(Mitsui Chemicals, Inc.), Super Beckamine.TM. G840 and G821
(Dainippon Ink & Chemicals, Inc.); methyl etherified melamine
resins such as Sumimal.TM. M-100, M-40S and M-55 (Sumitomo Chemical
Co., Ltd.), Cymel.TM. 303, 325, 327, 350 and 370 (Mitsui Cytec Co.,
Ltd.), Nikalac.TM. MS17 and MS15 (Sanwa Chemical Co., Ltd.) and
Resimine.TM. 741 (Monsanto Co.); methyl- and iso-butyl-mixed
etherified melamine resins such as Cymel.TM. 235, 202, 238, 254,
272 and 1130 (Mitsui Cytec Co., Ltd.), and Sumimal.TM. M66B
(Sumitomo Chemical Co., Ltd.); and methyl- and n-butyl-mixed
etherified melamine resins such as Cymel.TM. XV805 (Mitsui Cytec
Co., Ltd.) and Nikalac.TM. MS95 (Sanwa Chemical Co., Ltd.).
[0081] Said optionally-blocked polyisocyanate compounds usable as
the curing agent include both of polyisocyanate compounds having
free isocyanate groups and those in which isocyanate groups are
blocked.
[0082] Examples of polyisocyanate compounds having free isocyanate
groups include organic polyisocyanates per se, e.g., aliphatic
diisocyanates such as hexamethylenediisocyanate and
trimethylhexamethylenediisocyanate; cycloaliphatic diisocyanates
such as hydrogenated xylylenediisocyanate and
isophoronediisocyanate; aromatic diisocyanates such as
tolylenediisocyanate and 4,4'-diphenylmethanediisocyanate; and
polyisocyanate compounds having not less than 3 isocyanate groups
such as triphenylmethane-4,4',4''-triisocyanate,
1,3,5-triisocyanatebenzene, 2,4,6-triisocyanatetoluene and
4,4'-dimethyldiphenylmethane-2,2',5,5'-tetraisocyanate. These
organic polyisocyanates may be used in such forms as adducts with
polyhydric alcohol, low molecular weight polyester resin, water or
the like; or cyclized polymers composed of these organic
polyisocyanates, or isocyanate biuret.
[0083] As commercially available polyisocyanate compounds having
free isocyanate groups, for example, Burnock.TM. D-750, -800,
DN-950, DN-970 and DN-15-455 (Dainippon Ink & Chemicals, Inc.);
Desmodur.TM. L, N, HL and N3390 (Sumitomo Bayer Urethane Co.,
Ltd.); Takenate.TM. D-102, -202, -110 and -123N (Takeda Chemical
Industries, Ltd.); Coronate.TM. EH, L, HL and 203 (Nippon
Polyurethane Industry Co., Ltd.); and Duranate.TM. 24A-90CX (Asahi
Chemical Industry Co., Ltd.) may be named.
[0084] As polyisocyanate compounds in which isocyanate groups are
blocked, those formed by blocking isocyanate groups in the
above-described polyisocyanate compounds having free isocyanate
groups, with a known blocking agent such as oxime, phenol, alcohol,
lactam, malonic acid ester or mercaptane can be used. Typical
commercially available polyisocyanate compounds whose isocyanate
groups are blocked include Burnock.TM. D-550 (Dainippon Ink &
Chemicals, Inc.), Takenate.TM. B-815-N (Takeda Chemical Industries,
Ltd.), Additol.TM. VXL-80 (Hoechst AG, Germany), Coronate.TM. 2507
(Nippon Polyurethane Industry Co., Ltd.) and Desmodur.TM. N3500
(Sumitomo Bayer Urethane Co., Ltd.).
[0085] The aqueous medium which is used when necessity arises can
be suitably selected from those useful for preparing the pigment
dispersions as earlier explained.
[0086] The fine polymer particles are provided by a polymer which
does not dissolve in water-based paint compositions of the present
invention but disperses as fine particles. Suitable average
particle size normally is within a range of 0.01-1 .mu.m,
preferably 0.05-0.8 .mu.m. Inside of the particles may either be
crosslinked or not, the former being preferred. As such fine
polymer particles, those known per se as flow property regulator in
the field of paint can be used.
[0087] Where an optionally-blocked polyisocyanate compound is used
as the curing agent, organometal catalysts such as dibutyltin
diacetate, dibutyltin dioctate, dibutyltin dilaurate and the like;
and amines such as triethylamine, diethanolamine and the like can
be conveniently used as the curing catalyst. When an amino resin
such as melamine resin is used as the curing agent, such curing
catalyst as sulfonic acid compound, e.g., paratoluenesulfonic acid,
dodecylbenzensulfonic acid and dinonylnaphthalenesulfonic acid; or
amine-neutralization products of these sulfonic acid compounds are
conveniently used.
[0088] As examples of ultraviolet absorber, benzophenone,
benzotriazole, cyanoacrylate, salicylate and oxalic acid anilide
compounds may be named. As the ultraviolet stabilizer, hindered
amine compounds can be used.
[0089] The water-based paint compositions according to the
invention are useful as coloring paint compositions (including
metallic paint and iridescent paint) into which various pigments
such as coloring pigments, metallic pigments and iridescent
pigments are blended. In particular, they can be conveniently used
as top coating paint (coloring base coat) for automotive
finish.
[0090] The paint compositions according to the invention can be
applied onto various substrate, following the practice known per
se, and can form cured coating film when baked normally at
temperatures of from about 80.degree. C. to about 180.degree. C.,
for about 10-60 minutes. Where a short time baking is desired, for
example, a cured coating film can be formed by baking under such
conditions as will attain the highest temperature of from about
180.degree. C. to about 250.degree. C. of the material being baked,
for about 20-about 60 seconds.
[0091] Substrate to be coated with the paint compositions of the
present invention are subject to no specific limitation, examples
of which include metallic substrate such as steel sheet, aluminum,
tin and the like; other substrate such as of mortar, cement,
plastics, glass and the like; and these substrates which have been
subjected to surface treatment and/or coating film formation. In
particular, metallic substrates and plastic substrates are suitable
for use.
[0092] Examples of steel sheet include cold-rolled steel sheet,
molten galvanized steel sheet, electrogalvanized steel sheet,
aluminum plated steel sheet, stainless steel sheet, copper plated
steel sheet, tin plated steel sheet, lead-tin alloy plated steel
sheet (ternesheet); steel sheet plated with zinc alloy such as
iron-zinc, aluminum-zinc, nickel-zinc alloys and the like. As
surface-treated steel sheet, for example, steel sheet which is
given a chemical treatment such as phosphate treatment, chromate
treatment and the like may be named.
[0093] As the substrate on which coating film has been formed, a
substrate which has been optionally surface treated and thereafter
primer-coated, or said substrate which is further coated with an
inter-coat can be used.
[0094] When a paint composition according to the present invention
is used for automotive finish, typical substrates include: a
chemically treated steel sheet which is further
electrodeposition-coated with primer and optionally coated with an
inter coat thereon; various plastic substrates (which have been
optionally surface treated, primer-coated or further coated with an
inter coat); and composite members which are combination of the
foregoing.
[0095] The electrodepositing paint for electrodeposition coating
may be anionic or cationic, cationic type being preferred because
of good corrosion resistance. As cationic electrodeposition paint,
any of those known per se can be used. For example, those
containing as the resin component a base resin having hydroxyl
groups and cationic groups and as the curing agent a blocked
polyisocyanate compound can be conveniently used.
[0096] The water-based paint compositions according to the present
invention are conveniently used for colored coating film-forming
compositions for 1-coat-1-bake finish of substrates, and for top
coating colored base paint compositions in 2-coat-1-bake (2C1B),
2-coat-2-bake (2C2B), 3-coat-1-bake (3C1B), 3-coat-2-bake (3C2B),
or 3-coat-3-bake (3C3B) systems.
[0097] Where the paint compositions according to the present
invention are used for colored top coating for automobiles, the top
coat can be formed through the steps of, applying the paint
composition onto a primer film such as an electrodeposited coating
film or onto an uncured or cured inter coat applied onto such a
primer film, by such means as electrostatic atomizing coating
(bell-type or the like) or aerosol coating, to a dry film thickness
of normally from about 10 to about 60 .mu.m; and allowing it to
stand for several minutes at room temperature, or forcedly drying
the film for several minutes at temperatures ranging from about 50
to about 80.degree. C.; thereafter applying a clear top coat paint
thereon; and baking the same at temperatures of from about 120 to
about 180.degree. C. normally for about 10-about 60 minutes. It is
also possible to apply a clear top coating paint onto the uncured
or cured colored top coat film, by such means as electrostatic
atomizing coating (bell-type or the like) or aerosol coating, to a
dry film thickness of normally from about 20 to about 100 .mu.m
followed by curing, to form multi-layered top coating film.
[0098] As such clear top coating paint to be applied onto the
above-described colored top coat, those conveniently used are clear
top coating paints comprising at least one base resin having a
crosslinkable functional group (e.g., hydroxyl, epoxy, carboxyl,
alkoxysilane group and the like) such as acrylic, vinyl, polyester,
alkyd and urethane resins; and at least one crosslinking agent for
crosslinking and curing the base resin, such as alkyletherified
melamine resin, urea resin, guanamine resin, optionally-blocked
polyisocyanate compound, epoxy resin and carboxyl-containing
compound. In such clear top coating paint, convenient blend ratio
of the base resin and the crosslinking agent is, based on the sum
of the two components, normally 50-90% by weight of the base resin
component and 10-50% by weight of the cross-linking agent
component. The form of such clear top coating paint is subject to
no specific limitation, and it can take any desired form such as
organic solvent type, non-aqueous liquid dispersion type, aqueous
solution type, aqueous dispersion (slurry) type, high solid type or
powder type.
Water-Based Ink Composition
[0099] According to this invention, water-based ink composition can
be prepared from the above-mentioned water-based pigment dispersion
as it is, or from said water-based pigment dispersion and, added
thereto if necessary, additives such as aqueous medium, water
soluble resin, thickening agent, fluidity adjustor, film forming
assistant, surfactant, pH adjustor, mildew-proofing agent,
antioxidant, ultraviolet absorbing agent, ultraviolet stabilizing
agent and chelating agent and dye stuffs as well.
[0100] As aqueous medium, anyone may be selected for use from those
explained above as ones which are usable where necessary for the
production of the water-based pigment dispersion of this
invention.
[0101] As water soluble resin, there may be used, from the
viewpoint of ink property control, polyethylene imine, polyamines,
polyvinyl pyrrolidone, cellulose derivative, polysaccharides,
acrylic emulsion or polyurethane emulsion.
[0102] Dispersed particles which are contained in the water-based
ink composition of this invention have preferably an average
particle size in a range of 1 to 300 nm, in particular 1 to 200 nm.
The viscosity of ink liquid is preferably within a range of 1.0 to
10 mPas, in particular 1.5 to 7 mPas.
[0103] The water-based ink composition of this invention is in
particular suitable as ink-jet ink, and is used for ink-jet drawing
by usual ink-jet drawing system. Ink-jet drawing system may be any
of piezo ink-jet type, thermal ink-jet type or any other known
type. The water-based ink composition of this invention may be
applied not only to normal ink-jet drawing device but also to a
drawing device which is equipped with heater or the like with which
to control ink drying; to a recording device which is equipped with
intermediate transfer mechanism by which to print recording
material on an intermediate medium and then to transfer the
resultant print on recording medium such as paper; and to automatic
drawing device by which to directly paint wall, outdoor sign board
or automobile body.
[0104] Substrate on which the ink composition of this invention is
to be applied is not restricted in particular. There may be
mentioned base material such as paper, metal or plastics; base
material such as mortar or slate; or these base materials which
have been subjected to surface treatment and/or coating film
formation.
EXAMPLES
[0105] Hereinafter the invention is explained in further details,
referring to production examples, working examples and comparative
examples, in which parts and percentages are by weight unless
otherwise specified.
Preparation of Pigment Dispersing Resins
Example 1
[0106] An ordinary reaction vessel for producing acrylic resins,
equipped with a stirrer, thermometer and a reflux condenser was
charged with 45 parts of ethylene glycol monobutyl ether. The
content in the vessel was heated under stirring, and maintained at
110.degree. C. Into the system, a mixture of 10 parts of styrene,
40 parts of methyl methacrylate, 25 parts of n-butyl methacrylate,
10 parts of 2-hydroxyethyl methacrylate, 3 parts of methacrylic
acid, 7 parts of 2-(methacryloyloxy)ethyltrimethyl ammonium
chloride, 5 parts of "NF BISOMER.TM. PEM6E" (trademark of
polyethylene glycol monomethacrylate having a molecular weight of
about 350, manufactured by Dai-ich Kogyo Seiyaku Co., Ltd.,), 4
parts of azobisisobutyronitrile and 15 parts of isobutyl alcohol
was added dropwise over a period of 3 hours, followed by 30
minutes' aging at 110.degree. C. Then an additional catalytic
liquid mixture of 20 parts of ethylene glycol monobutyl ether and
0.5 part of azobisisobutyronitrile was added dropwise over a period
of 1 hour, followed by an hour's aging at 110.degree. C. and
cooling. Thus, a pigment dispersing resin (A-1) solution having a
solid content of 55% was obtained.
Examples 2-9 and Comparative Examples 1-11
[0107] Example 1 was repeated except that the formulation of the
used components was varied for each run as shown in the following
Tables 1 and 2, to provide solutions of pigment dispersing resins
(A-2) to (A-9), and solutions of pigment dispersing resins (AC-1)
to (AC-11). The solid contents of these solutions, and resin acid
values of these resins are as shown in the same Tables 1 and 2. The
note (*1) in Tables 1 and 2 means as follows Incidentally, the
amount of NF BISOMER.TM. S20W in Table 1 is shown by solid content.
TABLE-US-00001 TABLE 1 Examples 1 2 3 4 5 6 7 8 9 Solution of
pigment-dispersing resin A-1 A-2 A-3 A-4 A-5 A-6 A-7 A-8 A-9
Ethylene glycol monobutyl ether 45 35 38 38 38 38 38 38 38 Isobutyl
alcohol 32 32 32 32 32 32 32 Styrene 10 10 Methyl methacrylate 40
40 50 48 40 40 50 48 40 n-Butyl acrylate 20 20 20 20 20 20 20
n-Butyl methacrylate 25 25 2-Ethylhexyl methacrylate Isostearyl
acrylate 10 10 Lauryl methacrylate 2-Hydroxyethyl methacrylate 10
10 2-Hydroxyethyl acrylate 5 5 5 5 5 5 5 Methacrylic acid 3
Dimethylaminoethyl methacrylate 10 Methacryloyloxyethyl trimethyl 7
5 7 5 5 ammonium chloride 2-Acrylamide-2-methylsulfonic acid 5 5 7
5 NF BISOMER .TM. PEM6E 5 10 NF BISOMER .TM. S20W (*1) 20 20 20 20
20 20 20 Deionized water 10 Azobisisobutyronitrile 4 4 1 1 1 1 1 1
1 Isobutylalcohol 15 20 Additional Ethyleneglicol 20 15 10 10 10 10
10 10 10 catalytic monobutyl ether mixture Azobisisobutyronitrile
0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Special Solid content (%) 55 55
50 50 50 50 50 50 50 value Resin acid value (mgKOH/g) 19.6 5 -- --
-- -- 38 50 38 Hydroxyl value (mgKOH/g) 43 43 24 24 24 24 24 24 24
Weight average molecular weight 20000 20000 35000 35000 35000 35000
35000 35000 35000 Note (*1) NF BISOMER .TM. S20W: Trademark of 50%
water-diluted methoxy polyethylene glycol monomethacrylate having a
molecular weight of about 2080, manufactured by Dai-ichi Kogyo
Seiyaku Co., Ltd.)
[0108] TABLE-US-00002 TABLE 2 Examples 1 2 3 4 5 6 7 8 9 10 11
Solution of pigment-dispersing resin AC-1 AC-2 AC-3 AC-4 AC-5 AC-6
AC-7 AC-8 AC-9 AC-10 AC-11 Ethylene glycol monobutyl ether 55 55 55
55 55 55 65 25 38 50 33 Isobutyl alcohol 32 20 32 Styrene 10 10 10
10 10 Methyl methacrylate 40 40 30 36 33 32 32 32 55 44 60 n-Butyl
acrylate 20 20 25 n-Butyl methacrylate 39 30 20 20 20 20 20
2-Ethylhexyl methacrylate 20 20 20 20 20 Lauryl methacrylate 10
2-Hydroxyethyl methacrylate 10 5 13 10 10 10 10 10 10
2-Hydroxyethyl acrylate 5 5 Methacrylic acid 6 5 7 6 5 8 8 8 Acryl
acid 6 Dimethylaminoethyl methacrylate 5 20 Methacryloyloxyethyl
trimethyl 8 ammonium chloride 2-Acrylamide-2-methylsulfonic acid 2
5 NF BISOMER .TM. PEM6E 10 Deionized water 5 Azobisisobutyronitrile
4 4 4 4 8 4 1 8 1 1 1 Isobutylalcohol 5 5 5 5 5 5 15 20 Additional
Ethyleneglicol monobutyl 20 20 Gelatinized 20 15 20 20 20 10 10 10
catalytic ether mixture Azobisisobutyronitrile 0.5 0.5 0.5 0.5 0.5
0.5 0.5 0.5 0.5 0.5 Special Solid content (%) 55 55 55 55 55 50 60
50 50 50 value Resin acid value 39 32 39 34 52 52 52 -- 47 38
(mgKOH/g) Hydroxyl value 43 21.5 43 43 43 43 43 24 43 24 (mgKOH/g)
Weight average molecular 20000 20000 20000 20000 20000 40000 15000
35000 40000 35000 weight
Synthesis Example 1
[0109] A reaction vessel equipped with a stirrer, thermometer,
rectification column and nitrogen inlet pipe was charged with 208.8
parts of isophthalic acid, 387.5 parts of hexahydrophthalic acid,
275.5 parts of adipic acid, 198.1 parts of neopentyl glycol, 371.1
parts of 1,6-hexanediol and 171.1 parts of trimethylolpropane,
which were heated under stirring while nitrogen gas was introduced.
After the temperature reached 160.degree. C., the system was
gradually heated to 235.degree. C. over a period of 3 hours,
followed by 1.5 hours' aging. Thereafter the rectification column
was switched to reflux condenser, and the reaction was conducted
after introduction of 100 parts of toluene, under reflux. The
reaction was continued for 6 hours at 235.degree. C., and
thereafter the toluene was removed under reduced pressure. The
system was cooled to 170.degree. C., followed by the addition of
120.8 parts of trimellitic anhydride and 30 minutes' aging at
170.degree. C. Then, 322 parts of butyl cellosolve was added, and
the system was thereafter cooled to 80.degree. C. Subsequently, 4
parts of N,N-dimethylaminoethanol was added, and the system was
allowed to stand at 80.degree. C. for 30 minutes, and was then
cooled to 50.degree. C. Subsequently, 2600 parts of deionized water
was added, and the resultant mixture was stirred for 30 minutes.
Thus, a polyester resin (PP-1) solution having a solid
concentration of 35% was obtained. Thus obtained resin had an acid
value of 90 mgKOH/g, a hydroxyl value of 55 mgKOH/g and a weight
average molecular weight of 28,000.
Preparation of Water-Based Pigment Dispersions
Examples 10 to 17 and Comparative Examples 12 to 21
[0110] A wide-mouthed glass bottle of 225 cc in capacity was fed
with those pigment dispersing resin solutions which had been
produced in the above Examples 1 to 2 and Comparative Examples 1 to
8, pigment, and, if necessary, with neutralizing amine
(N,N-dimethylamino ethanol) as well, and further with deionized
water at the compositional formulation as shown by Tables 3 and 4
below, and was further fed with glass beads of about 1.3 mm in
diameter as a dispersing medium. The bottle was then sealed, and
the content was dispersed with a paint shaker for 4 hours to give
water-based pigment dispersions (B-1) to (B-8) and (BC-1) to
(BC-10).
Preparation of Water-Based Ink
Examples 18 to 42 and Comparative Examples 22 to 36
[0111] A wide-mouthed glass bottle of 225 cc in capacity was fed
with those pigment dispersing resin solutions which had been
produced in the above Examples 3 to 9 and Comparative Examples 9 to
11, the polyester resin solution which had been prepared in the
above-mentioned Synthesis Example 1, pigment, and, if necessary,
with neutralizing amine (N,N-dimethylamino ethanol) as well, and
further with deionized water at the compositional formulation as
shown by Tables 5 and 6 below, and was further fed with glass beads
of about 1.3 mm in diameter as a dispersing medium. The bottle was
then sealed, and the content was dispersed with a paint shaker for
4 hours to give water-based ink. In the above, acrylic resin
solution (AC-10) and polyester resin solution (PP-1) each for
dilution, and neutralizing amine were added after pigment
dispersing resin solutions and pigments had been sufficiently
dispersed.
[0112] The following are explanations of notes in Tables 3 to 6.
TABLE-US-00003 (NOTE 1) RT 355D: an organic red pigment
manufactured by Ciba Specialty Chemicals, Inc., under tradename of
"Cinquasia Magenta RT 355D" (NOTE 2) G 314: an organic blue pigment
manufactured by Sanyo Color Works, Ltd., under tradename of "Cyanin
Blue G314" (NOTE 3) MT500HD: tradename of an inorganic white
pigment manufactured by TAYCA Corporation (NOTE 4) Raven 5000 UIII:
tradename of carbon black pigment manufactured by Columbia Carbon
Co., Ltd. (NOTE 5) Disper BYK-192: tradename of wetting-dispersing
agent manufactured by BYK-Chemie Co. (NOTE 6) TG730: tradename of
wetting-dispersing agent manufactured by Kyoei Kagaku K.K. (NOTE 7)
Disper BYK-182: tradename of wetting-dispersing agent manufactured
by BYK-Chemie Co. (NOTE 8) Disper BYK-191: tradename of
wetting-dispersing agent manufactured by BYK-Chemie Co. (NOTE 9)
S#2000: tradename of wetting-dispersing agent manufactured by
Avecia Ltd. (NOTE 10) BYK-028: trademark of anti-foaming agent
manufactured by BYK-Chemie Co.
Performance Test
[0113] Water-based pigment dispersions which had been obtained in
the above Examples 10 to 17 and Comparative Examples 12 to 21 were
subjected to performance test by the following test method. Results
are shown in Tables 3 and 4 which are mentioned later. Besides,
each of water-based ink which had been obtained in the above
Examples 18 to 42 and Comparative Examples 22 to 36 was also
subjected to performance test by the following test method. Results
are shown in Tables 5 and 6 which are mentioned later.
Performance Test Method
Appearance of Coating Film:
[0114] Each of the pigment dispersion paste was applied onto a
100.times.200 mm transparent PET film with a bar coater to a dry
film thickness of 15 .mu.m, and baked at 140.degree. C. for 15
minutes. The extent of turbidity of the coating on the PET film was
visually evaluated according to the following grading standard:
[0115] .smallcircle.: Uniform and perfectly free of turbidity.
[0116] .DELTA.: Slightly turbid. [0117] x: Considerably turbid.
State of Paste:
[0118] The state of each water-based ink in glass container was
visually observed according to the following criteria. [0119]
.smallcircle.: Uniform, and perfectly free of precipitate and foam.
[0120] .DELTA.: A small amount of precipitate and foam is observed.
[0121] x: A considerable amount of precipitate and foam is
observed. Gloss:
[0122] Each pigment dispersion was applied onto PET film with a
doctor blade so that coating film thickness might be 100 .mu.m.
Water-based ink was applied onto PET film with a doctor blade so
that coating film thickness might be 50 .mu.m. The gloss of dried
coating films of pigment dispersion and of water-based ink was
determined by the measurement of 60.degree. mirror surface
reflectivity in accordance with JIS K5400 7.6 (1990).
Light Transmission:
[0123] Each pigment dispersion was applied onto PET film with a
doctor blade so that coating film thickness might be 100 .mu.m.
Water-based ink was applied onto PET film with a doctor blade so
that coating film thickness might be 50 .mu.m. The light
transmission (%) of dried coating films of pigment dispersion and
of water-based ink was determined with a turbidimeter (COH-300) in
accordance with the equation below, and, thus, transparency was
evaluated: Light .times. .times. transmission .times. .times. ( % )
= 100 .times. [ 1 - ( scattered light intensity radiated light
intensity ) ] ##EQU1## Viscoelasticity Characteristics:
[0124] Viscosity [Pascalsec (Pasec.)] and yield point
(dyn/cm.sup.2) were measured with a dynamic viscoelasticity
measuring apparatus, MR-300 (Rheology Co.).
Blackness:
[0125] Water-based ink which had been prepared in Examples 18 to 24
and Comparative Examples 22 to 26 were each applied onto PET film
with a doctor blade so that coating film thickness might be 50
.mu.m. The blackness of dried coating film was evaluated by BI
value. "BI value", which is an abbreviation of Blackness Index, is
expressed by the following equation: BI
value=(1-L*/3.5).times.100
[0126] L* is the index of brightness as shown by JIS Z-8105. The
higher BI value means the better blackness. [0127] BI value is 100:
Perfect blackness [0128] BI value is 0: Marginal blackness which is
recognized by human eye as such [0129] BI value is less than 0:
Gray Hue--Coloring Power:
[0130] Each of water-based ink which had been prepared in Examples
32 to 42 and Comparative Examples 33 to 36 was applied onto black
and white PET films with a doctor blade so that coating film
thickness might be 50 .mu.m. L*, a* and b* of dried coating film
was measured with a spectrocolorimeter (made by BYK-Chemie Co.),
and, thus, hue and coloring power were evaluated. It was known from
the results of L*, a* and b* that Examples showed strong coloring
power and improved chroma. TABLE-US-00004 TABLE 3 Example 10 11 12
13 14 15 16 17 Pigment dispersion B-1 B-2 B-3 B-4 B-5 B-6 B-7 B-8
Resin solution for Kind A-1 A-1 A-1 A-1 A-2 A-2 A-2 A-2 dispersing
pigment Amount 181.8 181.8 181.8 181.8 181.8 181.8 181.8 181.8
Pigment RT 355D (Note 1) 100 100 G 314 (Note 2) 100 100 MT500HD
(Note 3) 200 200 Raven 5000 UIII (Note 4) 20 20
N,N-dimethylaminoethanol 0 0 0 0 1.1 1.1 1.1 1.1 Deionized water
327.2 327.2 327.2 327.2 327.2 327.2 327.2 327.2 Test result Coating
film appearance .smallcircle. .smallcircle. .smallcircle.
.smallcircle. .smallcircle. .smallcircle. .smallcircle.
.smallcircle. Gloss (60.degree.) 92 94 88 89 91 93 85 88 Light
transmission (%) 90 92 85 -- 91 91 78 -- Viscosity (Pa sec) 1.3 1.5
1.2 1.5 1.3 1.6 1.4 1.2 Yield point (dyn/cm.sup.2) 4.2 3.5 2.4 5.3
3.1 2.9 3.5 3.5
[0131] TABLE-US-00005 TABLE 4 Example 12 13 14 15 16 17 18 19 20 21
Pigment dispersion BC-1 BC-2 BC-3 BC-4 BC-5 BC-6 BC-7 BC-8 BC-9
BC-10 Resin solution for Kind AC-1 AC-2 AC-4 AC-5 AC-6 AC-6 AC-6
AC-6 AC-7 AC-8 dispersing pigment Amount 181.8 181.8 181.8 181.8
181.8 181.8 181.8 181.8 200 166.7 Pigment RT 355D (Note 1) 100 G
314 (Note 2) 100 MT500HD (Note 3) 200 Raven 5000 UIII (Note 4) 20
20 20 20 20 20 20 N,N-dimethylaminoethanol 3.1 2.5 3.1 2.6 4.1 4.1
4.1 4.1 4.1 4.1 Deionized water 327.2 327.2 327.2 327.2 327.2 327.2
327.2 327.2 309 342.3 Test result Coating film appearance X .DELTA.
.DELTA. .DELTA. .DELTA. .DELTA. .DELTA. .DELTA. .DELTA. X Gloss
(60.degree.) 71 76 78 74 84 82 72 78 83 72 Light transmission (%)
-- -- -- -- 86 85 70 -- -- -- Viscosity (Pa sec) 1.5 1.3 1.4 1.5
2.5 2.1 2.9 5.5 11.2 1.8 Yield point (dyn/cm.sup.2) 5.8 4.2 3.9 5.9
8.5 7.9 8.5 11.5 39.1 3.9
[0132] TABLE-US-00006 TABLE 5 Example Comparative Example 18 19 20
21 22 23 24 22 23 24 25 26 Resin solution for Kind A-3 A-4 A-5 A-6
A-7 A-8 A-9 AC-9 AC-10 AC-11 BYK-192 TG-730 dispersing pigment
Amount 14.8 14.8 14.8 14.8 14.8 14.8 14.8 14.8 14.8 14.8 7.4 18.5
Pigment; C.I. Pigment Black 7 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3 4.3
4.3 4.3 4.3 Deionized water 70.9 70.9 70.9 70.9 70.9 70.9 70.9 70.9
70.9 70.9 78.3 67.2 Test State of paste .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .DELTA. .DELTA. .DELTA. X X result Viscosity (Pa sec)
0.044 0.07 0.06 0.04 0.055 0.07 0.08 0.08 0.12 0.09 0.37 0.43 Yield
point (dyn/cm.sup.2) 1.7 3.5 3.5 1.5 1.7 3.2 3.6 4.6 5.2 3.7 4.9
5.3 Blackness; B1 value 50.3 48.1 48.5 52.3 46.6 46.2 46.5 10 0 0
21 15 Gloss (60.degree.) 91 90 90 92 90 90 89 80 25 60 89 85
Example Comparative Example 25 26 27 28 29 30 31 27 28 29 30 31 32
Resin solution Kind A-3 A-4 A-5 A-6 A-7 A-8 A-9 AC-9 AC-10 AC-11
BYK-182 BYK-191 S#20000 for dispersing Amount 8.6 8.6 8.6 8.6 10 10
10 8.6 8.6 8.6 11.6 5 5 pigment Pigment; C.I. Pigment 8.5 8.5 8.5
8.5 8.5 8.5 8.5 Blue 15:3 Pigment; C.I. Pigment 10 10 10 10 10 10
Red 122 BYK-028 1.2 1.2 1.2 1.2 1.2 1.2 Deionized water 82.9 82.9
82.9 82.9 40 40 40 82.9 82.9 82.9 38.4 45 45 Test State of paste
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .DELTA. .DELTA. .DELTA.
.DELTA. .DELTA. .DELTA. result Viscosity 0.012 0.015 0.02 0.018
0.03 0.035 0.06 0.084 0.032 0.035 0.083 0.08 0.13 (Pa sec) Yield
point 1.3 1.3 1.5 1.7 2.2 2.2 7.1 1.96 10.5 1.8 8.1 7.3 57.4
(dyn/cm.sup.2) Gloss (60.degree.) 60.5 60.2 59.6 58.9 99 99 98 52.8
54 20.4 98 98 97
[0133] TABLE-US-00007 TABLE 6 Example Comparative Example 32 33 34
35 36 37 38 39 40 41 42 33 34 35 36 Resin solution Kind A-3 A-4 A-5
A-6 A-7 A-8 A-9 A-3 A-4 A-5 A-6 S#20000 BYK191 A-3 A-3 for
dispersing Amount 10 10 10 10 10 10 10 10 10 10 10 5 5 10 10
pigment Pigment; G-314 10 10 10 10 10 10 10 10 10 10 10 10 10 10 10
AC-10 30 30 30 30 30 30 30 30 30 30 30 30 30 PP-1 42.8 4.28
Aminomethyl propanol 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9
Deionized water 57.3 57.3 57.3 57.3 57.3 57.3 57.3 92.5 79.6 92.5
92.5 57.3 57.3 92.5 79.6 Test State of paste .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. X .DELTA. X X result Light transmission
(%) 100 100 100 100 100 100 100 98.5 98.4 97.8 98.2 84.7 80.4 85.3
81.9 L* 2.1 2.2 2.5 2 2.6 2.6 2.8 2.8 2.9 3.2 2.9 6.2 5 5 6.2 a*
7.3 7.3 7.8 7.1 8.6 8.5 8.9 9 8.7 9.1 9.2 16.4 15.5 10.5 15.3 b*
-19.1 -19.6 -20.3 -19.5 -21.6 -21.2 -22.3 -21.7 -22.3 -23.5 -20.5
-29.8 -29.9 -27.4 -30.5
Synthesis of Base Resin for Paint
Synthesis Example 2
[0134] A reaction vessel for producing acrylic resins, equipped
with a stirrer, thermometer and a reflux condenser was charged with
40 parts of ethylene glycol monobutyl ether and 30 parts of
isobutyl alcohol, which were heated under stirring. When the
temperature of the system reached 100.degree. C., a mixture of the
following monomers was added to the system dropwise, over a period
of 3 hours: TABLE-US-00008 Styrene 10 parts Methyl methacrylate 38
parts n-Butyl acrylate 25 parts 2-Hydroxyethyl methacrylate 20
parts Acrylic acid 7 parts 2,2'-Azobisisobutyronitrile 1 part
[0135] After the dropwise addition was completed, the system was
maintained at 100.degree. C. for further 30 minutes, and thereafter
an additional catalytic solution which was a mixture of 0.5 part of
2,2'-azobisisobutyronitrile and 10 parts of ethylene glycol
monobutyl ether was added dropwise, consuming an hour, followed by
further an hour's stirring at 100.degree. C. and cooling.
Subsequently, 15 parts of isobutylalcohol was added, and, when the
temperature of the resulting mixture became 75.degree. C., 4 parts
of N,N-dimethylamino ethanol was added, and the resultant mixture
was stirred for 30 minutes to give an acrylic resin solution (AP-1)
having a solid concentration of 50%. The obtained resin had an acid
value of 54 mgKOH/g, a hydroxyl value of 86 mgKOH/g and a weight
average molecular weight of 32,000.
Synthesis Example 3
[0136] A reaction vessel equipped with a stirrer, thermometer,
rectification column and nitrogen inlet pipe was charged with 317.8
parts of isophthalic acid, 196.5 parts of hexahydrophthalic acid,
372.6 parts of adipic acid, 268 parts of neopentyl glycol, 217.8
parts of 1,6-hexanediol and 263.5 parts of trimethylolpropane,
which were heated under stirring while nitrogen gas was introduced.
After the temperature reached 160.degree. C., the system was
gradually heated to 235.degree. C. over a period of 3 hours,
followed by 1.5 hours' aging. Thereafter the rectification column
was switched to reflux condenser, and the reaction was conducted
after introduction of 100 parts of toluene, under reflux. The
reaction was continued for 6 hours at 235.degree. C., and
thereafter the toluene was removed under reduced pressure. The
system was cooled to 170.degree. C., followed by addition of 122.5
parts of trimellitic anhydride and 30 minutes' aging at 170.degree.
C. Further 322 parts of butyl cellosolve was added, and the system
was thereafter cooled to 80.degree. C., 4 parts of
N,N-dimethylaminoethanol was added, and the system was allowed to
stand at 80.degree. C. for 30 minutes, followed by cooling to
50.degree. C., addition of 2600 parts of deionized water and 30
minutes' stirring. Thus a polyester resin (PP-2) solution having a
solid concentration of 50% was obtained. The obtained resin had an
acid value of 56 mgKOH/g, a hydroxyl value of 90 mgKOH/g and a
weight average molecular weight of 25,000.
Synthesis Example 4
[0137] A reaction vessel for producing acrylic resins, equipped
with a stirrer, thermometer and a reflux condenser was charged with
400 parts of deionized water and 2.4 parts of Newcol.TM. 562SF
(Nippon Nyukazai Co., Ltd., a surfactant), which were heated under
stirring. When the temperature reached 82.degree. C., a
pre-emulsion forming mixture was charged, which had been prepared
by mixing 6 parts of styrene, 8.5 parts of n-butyl acrylate, 0.5
part of allyl methacrylate, 0.175 part of Newcol.TM. 562SF and 7.5
parts of deionized water and stirring the mixture with disper at
about 1000 r.p.m. for 10 minutes. Twenty (20) minutes after
charging said pre-emulsion forming mixture, 15 parts of deionized
water and 0.54 part of potassium persulfate were added. After
further 10 minutes, while the system was still maintained at
82.degree. C., a first monomeric mixture formed by mixing 114 parts
of styrene, 161.5 parts of n-butyl acrylate, 9.5 parts of allyl
methacrylate, 3.325 parts of Newcol.TM. 562SF and 142.5 parts of
deionized water, stirring the mixture with a disper at about 1,000
r.p.m. for 10 minutes and adding thereto 15 parts of deionized
water and 0.54 part of potassium persulfate, was added dropwise
over a period of 3 hours. Then after intervening standing at
82.degree. C. for 30 minutes, a second monomeric mixture formed by
mixing 50 parts of styrene, 23 parts of n-butyl acrylate, 10 parts
of 2-hydroxyethyl acrylate, 5 parts of methacrylic acid, 1.6 parts
of Newcol.TM. 562SF and 60 parts of deionized water, stirring the
mixture with a disper at about 1,000 r.p.m. for 10 minutes and
adding thereto 15 parts of deionized water and 0.54 part of
potassium persulfate, was added dropwise over a period of 1.5
hours. After the addition, the system was maintained at 82.degree.
C. for 30 minutes, cooled, and when the temperature dropped to
75.degree. C., a mixture of 7 parts of N,N-dimethylamionoethanol
and 280 parts of deionized water was added dropwise over 15
minutes, followed by 15 minutes' standing at 75.degree. C. Upon
further cooling, an acrylic emulsion having a solid concentration
of 30% was synthesized.
Preparation of Colored Paint Composition
Example 43
[0138] There were mixed 132.2 parts water-based pigment dispersion
(B-1) as a pigment dispersion paste (30 parts as solid) which had
been prepared in Example 10, 30 parts (15 parts as solid) of the
acrylic polymer (AP-1) solution formed in Synthesis Example 2, 42.9
parts (15 parts as solid) of the polyester polymer (PP-2) formed in
Synthesis Example 3, 37.5 parts (30 parts as solid) of Cymel.TM.
325 (Mitsui Cytec Co., Ltd., a methyl etherified melamine resin
solution having a solid content of about 80%), 50 parts (15 parts
as solid) of the acrylic emulsion formed in Synthesis Example 4,
and further 1 part of 28% Primal.TM. ASE (which had been formed by
diluting "gPrimal.TM. ASE-60", a thickener manufactured by Japan
Acryl Chemicals Co., Ltd., with water to a solid content of 28%),
0.8 part of dimethylethanol amine, 230 parts of deionized water and
30 parts of 2-ethylhexyl alcohol, and, thus, there was obtained a
colored paint composition having a viscosity of 500 mPas. (measured
with B-type viscometer at 60 r.p.m.) and a pH of about 8.5.
Examples 44 to 45 and Comparative Examples 37 to 43
[0139] Example 43 was repeated except that the formulation of
components was varied for each run as shown in Table 7 which is
mentioned later, and, thus, there were obtained colored paint
compositions.
[0140] Using those paint compositions obtained in Examples 43 to 45
and Comparative Examples 37 to 43, test panels were prepared by the
following method.
Preparation of Test Panels
[0141] A 0.8 mm-thick cold rolled dull steel sheet which had been
chemically treated with zinc phosphate was applied with an epoxy
resin-based cationic electrodeposition paint to a dry film
thickness of about 20 .mu.m which was subsequently baked. Onto this
electrodeposited paint film, automotive polyester resin-based inter
coating paint was applied to a dry film thickness of about 20 .mu.m
and baked. This coated steel sheet was wet-sanded with #400 sand
paper, dried off and degreased with petroleum benzin. Onto so
degreased coat surface, each of the coloring paint compositions
whose viscosity had been adjusted to 500 mPas (measured with B-type
viscometer at 60 r.p.m.) was applied with minibell rotation type
electrostatic coater at a booth humidity of 70%, to a dry film
thickness of about 15 .mu.m, and allowed to stand at room
temperature for about 5 minutes for setting. Each of the paint film
was baked with an electric hot air dryer at 80.degree. C. for 10
minutes to evaporate off most of volatile components. Then, the
film was left to stand still in room to be cooled, and,
subsequently, was coated with an automotive acrylic resin-based
clear paint, "Magicron.TM. TC71" (manufactured by Kansai Paint Co.,
Ltd.) to a dry film thickness of about 40 .mu.m, followed by baking
with an electric hot air dryer at 140.degree. C. for 30 minutes,
and, thus, test panels were prepared.
[0142] Thus prepared test panels were subjected to various
performance tests by the following test methods, with the results
as given in Table 7 which is mentioned later.
Test Methods
Appearance of Coat Finish:
[0143] The appearance of coat finish was synthetically examined in
respect of gloss and fatness, and evaluated according to the
following criteria:
[0144] .smallcircle.: good; .DELTA.: poor; x: very poor.
Gloss:
[0145] Following JIS K5400 7.6 (1990), 60.degree.-specular gloss of
each coated film was measured.
Sharpness:
[0146] Sharpness was measured with a portable gloss distinctness
meter P.G.D-IV (Japan Color Research Institute). The higher the
measured value is, the better is the sharpness.
Intimate Adhesion:
[0147] Following JIS K-5400 8.5.2 (1990) lattice pattern tape
method, each eleven parallel straight lines were orthogonally drawn
vertically and horizontally at 1 mm intervals on the top coat film
surface on each test panel, to form one hundred 1 mm.times.1 mm
squares. Onto the same surface cellophane adhesive tape was applied
intimately. The tape was then rapidly peeled off, and the extent of
peeling of the squares was observed. Evaluation of adhesion was
made according to the following criteria: [0148] .smallcircle.: at
least 90 squares of the coat film remained unpeeled; [0149]
.DELTA.: no less than 50 but less than 90 squares emained unpeeled;
[0150] x: less than 50 squares remained unpeeled. Acid
Resistance:
[0151] An artificial rain (0.5 cc) of the following composition was
dropped onto each of the test panels which were heated on
80.degree. C. hot plate for 30 minutes and then washed with water.
The coated surfaces were visually examined and evaluated according
to the following grading standards: [0152] .smallcircle.: no change
observed on the coated surface; [0153] .DELTA.: no whitening or
swelling observed on the coated surface, but difference in level
was recognized at the boundaries; [0154] x: whitening or swelling
observed on the coated surface.
[0155] The artificial rain used was a blend of 19.6 g of 1 mg/g
aqueous solution of NaNO.sub.3; 5.2 g of 1 mg/g aqueous KNO.sub.3
solution,; 3.7 g of 1 mg/g aqueous solution of
CaCl.sub.2.2H.sub.2O,; 8.2 g of 1 mg/g aqueous solution of
MgSO.sub.4.7H.sub.2O; 73.3 g of 1 mg/g aqueous solution of
(NH.sub.4).sub.2 SO.sub.4,; 30.0 g of 0.1 N aqueous solution of
H.sub.2SO.sub.4; 20.0 g of 0.1 N aqueous solution of HNO.sub.3;
10.0 g of 0.05N aqueous solution of HCl, and 4.7 g of 1 mg/g
aqueous solution of NaF. The pH of the blend was adjusted to 1.0
with H.sub.2SO.sub.4.
Solvent Resistance:
[0156] In a 20.degree. C. room, each test panel surface was rubbed
with a piece of cotton gauze soaked with methyl ethyl ketone under
about 1 kg/cm.sup.2 load over a length of about 5 cm. After 50
times reciprocal rubbing, the surface condition of the test panel
was visually graded according to the following standard: [0157]
.smallcircle.: no change observed on the coated surface; [0158]
.DELTA.: scratches observed on the coated surface; and [0159] x:
whitening or swelling observed on the coated surface. Impact
Resistance:
[0160] Following JIS K-5400 8.3.2 (1990) DuPont impact resistance
test, a weight of 500 g with its hitting front end having a
diameter of about 12.7 mm was dropped on the coated film surface
facing upward, and, thus, the maximum height of weight was measured
as far as no damage was made on the coating film. The maximal value
is 50 cm. TABLE-US-00009 TABLE 7 Example Comparative Example 43 44
45 37 38 39 40 41 42 43 Pigment Kind B-1 B-4 B-8 BC-1 BC-2 BC-3
BC-4 BC-8 BC-9 BC-10 dispersing paste Amount 132.2 132.2 Acryl
polymer Kind AP-1 AP-1 AP-1 AP-1 AP-1 AP-1 AP-1 AP-1 AP-1 AP-1
solution Amount 30 30 Polyester polymer Kind PP-2 PP-2 PP-2 PP-2
PP-2 PP-2 PP-2 PP-2 PP-2 PP-2 solution Amount 42.9 42.9 Acryl
emulsion of Synthesis Example 4 66.7 66.7 Cymel 325 37.5 37.5 28%
Primal ASE-60 1.0 1.0 N,N-dimethylamino ethanol 0.8 0.8 Dionized
water 213.9 213.9 Coating film Coating film appearance
.largecircle. .largecircle. .largecircle. X X X X .DELTA. .DELTA. X
performance 60.degree. Gloss 87 84 85 62 66 69 67 72 72 64
Sharpness 1.2 1.2 1.2 0.5 0.7 0.7 0.8 0.9 0.9 0.7 Intimate adhesion
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.DELTA. .DELTA. .DELTA. .DELTA. Acid resistance .largecircle.
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.DELTA. .DELTA. Solvent resistance .largecircle. .largecircle.
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.DELTA. Impact resistance 50 50 50 30 35 35 30 35 30 30
INDUSTRIAL APPLICABILITY
[0161] The use of the water-based pigment dispersing resins of this
invention provides water-based pigment dispersions which excel in
wetting property and dispersing stability even at high pigment
concentration, and which have low viscosity and are excellent in
color developing property and weatherability. The use of said
water-based pigment dispersions in turn gives a coating composition
which excels not only in pigment color-developing property and in
coating film performance such as coating film appearance,
weatherability and physical properties, but also in pigment
dispersing stability, and which can be made to contain pigment at a
high concentration. The use of said water-based pigment dispersions
also gives a water-based ink composition which is excellent not
only in pigment color-developing property and dispersing stability
but also in sharpness, transparency and color developing
property.
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