U.S. patent application number 14/593536 was filed with the patent office on 2015-05-07 for cured product from a paint comprising an inorganic fine particle dispersant.
This patent application is currently assigned to DIC CORPORATION. The applicant listed for this patent is DIC CORPORATION. Invention is credited to Shinichi Kudo, Ryo Minakuchi, Tomoko Shishikura, Yasuhiro Takada.
Application Number | 20150126677 14/593536 |
Document ID | / |
Family ID | 45469413 |
Filed Date | 2015-05-07 |
United States Patent
Application |
20150126677 |
Kind Code |
A1 |
Takada; Yasuhiro ; et
al. |
May 7, 2015 |
CURED PRODUCT FROM A PAINT COMPRISING AN INORGANIC FINE PARTICLE
DISPERSANT
Abstract
Provided is a inorganic fine particle dispersant comprising, as
an essential component, a compound resin (A) in which a
polysiloxane segment (a1) having a structural unit represented by
general formula (1) and/or general formula (2) and a silanol group
and/or a hydrolyzable silyl group is bonded to a vinyl-based
polymer segment (a2) through a bond represented by general formula
(3). An inorganic fine particle dispersion liquid that contains the
inorganic fine particle dispersant and inorganic fine particles, an
inorganic fine particle dispersion containing the inorganic fine
particle dispersion liquid, a paint, and a cured product are also
provided.
Inventors: |
Takada; Yasuhiro;
(Sakura-shi, JP) ; Shishikura; Tomoko;
(Sakura-shi, JP) ; Minakuchi; Ryo; (Sakura-shi,
JP) ; Kudo; Shinichi; (Sakura-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DIC CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
DIC CORPORATION
Tokyo
JP
|
Family ID: |
45469413 |
Appl. No.: |
14/593536 |
Filed: |
January 9, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13810152 |
Mar 19, 2013 |
8962727 |
|
|
PCT/JP2011/065803 |
Jul 11, 2011 |
|
|
|
14593536 |
|
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Current U.S.
Class: |
524/588 |
Current CPC
Class: |
C08K 2003/2241 20130101;
C09D 7/45 20180101; B01F 17/0007 20130101; C08K 3/36 20130101; C09D
183/06 20130101; B01F 17/0071 20130101; C08G 77/16 20130101; C08G
77/18 20130101; C09D 7/61 20180101; C08K 5/10 20130101; C08K 3/22
20130101; C08G 77/20 20130101; C09D 183/06 20130101; C08K 3/36
20130101; C09D 183/06 20130101; C08K 3/22 20130101 |
Class at
Publication: |
524/588 |
International
Class: |
C09D 183/06 20060101
C09D183/06; C08K 3/22 20060101 C08K003/22; C08K 3/36 20060101
C08K003/36; C09D 7/12 20060101 C09D007/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 12, 2010 |
JP |
2010-157752 |
Claims
1. A cured product from a paint comprising an inorganic fine
particle dispersion, wherein the inorganic fine particle dispersant
uses an organic solvent or a liquid polymer as a dispersion medium,
wherein the inorganic fine particle dispersant comprises, as an
essential component, a compound resin (A) in which a polysiloxane
segment (a1) having a structural unit represented by general
formula (1) and/or general formula (2) and a silanol group and/or a
hydrolyzable silyl group is bonded to a vinyl-based polymer segment
(a2) through a bond represented by general formula (3), the bond
being formed as a result of a dehydration condensation reaction
between the silanol group and/or hydrolyzable silyl group of the
polysiloxane segment (a1) and a silanol group and/or hydrolyzable
silyl group of the vinyl-based polymer segment (a2): ##STR00006##
where in general formulae (1) and (2), R.sup.1, R.sup.2, and
R.sup.3 each independently represent a group having one
polymerizable double bond selected from the group consisting of
--R.sup.4--CH.dbd.CH.sub.2, --R.sup.4--C(CH.sub.3).dbd.CH.sub.2,
--R.sup.4--O--CO--C(CH.sub.3).dbd.CH.sub.2, and
--R.sup.4--O--CO--CH.dbd.CH.sub.2 (where R.sup.4 represents a
single bond or an alkylene group having 1 to 6 carbon atoms), an
alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3
to 8 carbon atoms, an aryl group, or an aralkyl group having 7 to
12 carbon atoms; and at least one selected from R.sup.1, R.sup.2,
and R.sup.3 is the group having a polymerizable double bond,
##STR00007## where in general formula (3), the carbon atom is part
of the vinyl-based polymer segment (a2) and the silicon atom bonded
only to the oxygen atom is part of the polysiloxane segment
(a1).
2. The cured product according to claim 1, wherein the vinyl-based
polymer segment (a2) has an alcoholic hydroxyl group.
3. The cured product according to claim 1, wherein the polysiloxane
segment (a1) content is 10 to 90 wt % relative to the total solid
content in the inorganic fine particle dispersant.
4. The cured product according to claim 1, wherein the inorganic
fine particles are silica fine particles or titanium oxide fine
particles.
5. An inorganic fine particle dispersion liquid comprising
inorganic fine particles and the inorganic fine particle dispersant
according to claim 1.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 13/810,152, filed on Mar. 19, 2013, which is a 371 of
International Application No. PCT/JP2011/065803, filed on Jul. 11,
2011, which is based upon and claims the benefit of priority from
the prior Japanese Patent Application No. 2010-157752, filed on
Jul. 12, 2010, the entire contents of which are incorporated herein
by reference.
TECHNICAL FIELD
[0002] The present invention relates to an inorganic fine particle
dispersant that can be used to disperse inorganic fine particles
such as silica fine particles in a dispersion medium and a reactive
compound and to an inorganic fine particle dispersion liquid and an
inorganic fine particle dispersion using the dispersant.
BACKGROUND ART
[0003] In order to achieve properties of organic polymers such as
formability and flexibility and properties of inorganic materials
such as heat resistance, wear resistance, and surface hardness,
studies on blending inorganic fine particles to organic polymers
have been widely conducted.
[0004] For example, according to a design that utilizes the
properties inherent to inorganic materials, a higher compounding
effect can be expected from blending inorganic fine particles
having smallest possible particle size at a high concentration.
This is because the smaller the particle size, the larger the
surface area of the inorganic fine particles per unit weight and
the wider the interface regions between organic polymers and
inorganic materials. When the concentration of the inorganic fine
particles is high, the properties of the inorganic materials can be
more strongly exhibited.
[0005] Most of such blend systems of organic polymers and inorganic
fine particles use liquid organic polymers, monomers which are
starting materials for organic polymers, organic solvents, and the
like, and are available as liquid products such as paints and inks
from the viewpoint of coating and handling ease. Meanwhile, it is
also known that when such inorganic fine particles are blended into
dispersion media at high concentrations, it is difficult to obtain
stable dispersion liquids and various problems arise during
manufacturing processes and adversely affect the value of products
obtained by the processes. In other words, inorganic fine particles
of extremely small particle size have high surface activity and
thus undergo secondary aggregation, resulting in problems such as
low dispersion stability due to the secondary aggregates and lack
of uniformity of properties such as coating film properties
differing among parts of coating films.
[0006] Examples of known techniques of dispersing inorganic fine
particles such as silica in organic polymers include a method with
which inorganic fine particles surface-treated with a coupling
agent are dispersed in a resin (refer to PTL 1), a method with
which inorganic fine particles are dispersed by using a surfactant
(refer to PTL 2), and a method with which inorganic fine particles
are dispersed by using a mixture of a lactone-modified
carboxyl-group-containing (meth)acrylate and caprolactone of
(meth)acrylic acid (refer to PTL 3).
[0007] PTL 1: Japanese Examined Patent Application Publication No.
7-98657
[0008] PTL 2: Japanese Examined Patent Application Publication No.
8-13938
[0009] PTL 3: Japanese Unexamined Patent Application Publication
No. 2000-281934
[0010] PTL 4: International publication No. 96/035755 pamphlet
[0011] PTL 5: Japanese Unexamined Patent Application Publication
No. 2006-328354
DISCLOSURE OF INVENTION
Problems to be Solved by the Invention
[0012] An object of the present invention is to provide an
inorganic fine particle dispersant capable of stably dispersing
inorganic fine particles such as silica fine particles in a
dispersion medium or a reactive compound at a high concentration,
an inorganic fine particle dispersion liquid having excellent
storage stability and fluidity, an inorganic fine particle
dispersion containing the inorganic fine particle dispersion
liquid, a paint that uses the dispersion, and a cured product
obtained by curing the paint.
Means for Solving Problems
[0013] The inventors of the present invention have found that a
compound resin that has a polysiloxane segment having a silanol
group and/or a hydrolyzable silyl group and a polymer segment other
than the polysiloxane can be used as an inorganic fine particle
dispersant capable of easily dispersing inorganic fine particles
such as silica fine particles and that an inorganic fine particle
dispersion liquid and an inorganic fine particle dispersion each in
which inorganic fine particles are dispersed by using the
dispersant have excellent storage stability and fluidity. It has
also been found that when the compound resin has a polymerizable
double bond, the inorganic fine particle dispersion becomes curable
by an active energy ray such as UV rays and the obtained coating
films have particularly excellent surface properties such as
weatherability and resistance to wear testing. In particular, it
has been found that when an acrylic monomer, a polyisocyanate, or
the like is used as the reactive compound, physical properties of a
coating film obtained by three-dimensional crosslinking between the
compound resin serving as a dispersant and the reactive compound
are particularly excellent.
[0014] A compound resin that has a polysiloxane segment having a
silanol group and/or a hydrolyzable silyl group and a polymer
segment other than the polysiloxane is the invention made by the
inventors (e.g., refer to PTL 4 and PTL 5). The compound resin is
developed as a curable paint. PTL 4 and PTL 5 describe that a
curable paint that uses the compound resin is particularly suitable
for use as paints for building exteriors and the like. However,
that this compound resin is useful as a dispersant for inorganic
fine particles has been completely unknown.
[0015] The present invention provides an inorganic fine particle
dispersant including, as an essential component, a compound resin
(A) in which a polysiloxane segment (a1) having a structural unit
represented by general formula (1) and/or general formula (2) and a
silanol group and/or a hydrolyzable silyl group is bonded to a
vinyl-based polymer segment (a2) through a bond represented by
general formula (3):
##STR00001##
(In general formulae (1) and (2), R.sup.1, R.sup.2, and R.sup.3
each independently represent a group having one polymerizable
double bond selected from the group consisting of
--R.sup.4--CH.dbd.CH.sub.2, --R.sup.4--C(CH.sub.3).dbd.CH.sub.2,
--R.sup.4--O--CO--C(CH.sub.3).dbd.CH.sub.2, and
--R.sup.4--O--CO--CH.dbd.CH.sub.2 (where R.sup.4 represents a
single bond or an alkylene group having 1 to 6 carbon atoms), an
alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3
to 8 carbon atoms, an aryl group, or an aralkyl group having 7 to
12 carbon atoms.)
##STR00002##
(In general formula (3), the carbon atom is part of the vinyl-based
polymer segment (a2) and the silicon atom bonded only to the oxygen
atom is part of the polysiloxane segment (a1).).
[0016] The present invention also provides an inorganic fine
particle dispersion liquid that contains the inorganic fine
particle dispersant and inorganic fine particles.
[0017] The present invention also provides an inorganic fine
particle dispersion in which inorganic fine particles and the
inorganic fine particle dispersant described above are dispersed in
a reactive compound.
Advantageous Effects of Invention
[0018] An inorganic fine particle dispersant according to the
present invention is capable of stably dispersing inorganic fine
particles such as silica fine particles and titanium oxide in a
reactive compound at a high concentration. The inorganic fine
particle dispersion obtained therefrom exhibits excellent storage
stability and fluidity. A paint that uses the dispersion is
particularly useful as building exterior paints required to have
long-term weatherability and paints for readily thermally
deformable substrates such as plastic when cured by heat or an
active energy ray, and has long-term outdoor weatherability (in
particular, crack resistance) and excellent wear resistance. In
particular, when the compound resin (A) has a polymerizable double
bond or an alcoholic hydroxyl group and an acrylic monomer,
polyisocyanate, or the like is used as the reactive compound,
three-dimensional crosslinking occurs between the compound resin
(A) serving as a dispersant and a reactive diluent and thus coating
films that have particularly high weatherability can be obtained.
Moreover, when the polysiloxane segment content in the compound
resin (A) serving as a dispersant is within a particular range and
a coating film is obtained by curing the resin with an active
energy ray such as a UV ray without conducting heating at high
temperature, the coating film can exhibit excellent wear resistance
and high adhesion to plastic substrates.
DESCRIPTION OF EMBODIMENTS
(Inorganic Fine Particle Dispersant--Compound Resin (A))
[0019] A compound resin (A) used in the present invention is a
compound resin in which a structural unit represented by general
formula (1) and/or (2) described above and a polysiloxane segment
(a1) having a silanol group and/or a hydrolyzable silyl group
(hereinafter simply referred to as polysiloxane segment (a1)) is
bonded to a vinyl-based polymer segment (a2) having an alcoholic
hydroxyl group (hereinafter simply referred to as vinyl-based
polymer segment (a2)) through a bond represented by general formula
(3) above.
[0020] A dehydration condensation reaction occurs between the
silanol group and/or hydrolyzable silyl group of the polysiloxane
segment (a1) described below and the silanol group and/or
hydrolyzable silyl group of the vinyl-based polymer segment (a2)
described below and a bond represented by general formula (3) above
is formed as a result. Accordingly, in general formula (3), the
carbon atom is part of the vinyl-based polymer segment (a2) and the
silicon atom bonded only to the oxygen atom is part of the
polysiloxane segment (a1).
[0021] Examples of the form of the compound resin (A) include a
compound resin having a graft structure in which the polysiloxane
segment (a1) is chemically bonded to the vinyl-based polymer
segment (a2) by forming a side chain and a compound resin having a
block structure in which the polymer segment (a2) and the
polysiloxane segment (a1) are chemically bonded.
(Compound Resin (A)--Polysiloxane Segment (a1))
[0022] The polysiloxane segment (a1) in the present invention is a
segment that has a structural unit represented by general formula
(1) and/or (2) and a silanol group and/or a hydrolyzable silyl
group.
(Structural Unit Represented by General Formula (1) and/or (2))
[0023] In particular, in general formulae (1) and (2), R.sup.1,
R.sup.2, and R.sup.3 each independently represent a group having
one polymerizable double bond selected from the group consisting of
--R.sup.4--CH.dbd.CH.sub.2, --R.sup.4--C(CH.sub.3).dbd.CH.sub.2,
--R.sup.4--O--CO--C(CH.sub.3).dbd.CH.sub.2, and
--R.sup.4--O--CO--CH.dbd.CH.sub.2 (where R.sup.4 represents a
single bond or an alkylene group having 1 to 6 carbon atoms), an
alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3
to 8 carbon atoms, an aryl group, or an aralkyl group having 7 to
12 carbon atoms.
[0024] Examples of the alkylene group having 1 to 6 carbon atoms
for by R.sup.4 include a methylene group, an ethylene group, a
propylene group, an isopropylene group, a butylene group, an
isobutylene group, a sec-butylene group, a tert-butylene group, a
pentylene group, an isopentylene group, a neopentylene group, a
tert-pentylene group, a 1 methylbutylene group, a 2-methylbutylene
group, a 1,2-dimethylpropylene group, a 1-ethylpropylene group, a
hexylene group, an isohexylene group, a 1-methylpentylene group, a
2-methylpentylene group, a 3-methylpentylene group, a
1,1-dimethylbutylene group, a 1,2-dimethylbutylene group, a
2,2-dimethylbutylene group, a 1-ethylbutylene group, a
1,1,2-trimethylpropylene group, a 1,2,2-trimethylpropylene group, a
1-ethyl-2-methylpropylene group, and a 1-ethyl-1-methylpropylene
group. In particular, R.sup.4 is preferably a single bond or an
alkylene group having 2 to 4 carbon atoms due to high availability
of the raw material.
[0025] Examples of the alkyl group having 1 to 6 carbon atoms
include a methyl group, an ethyl group, a propyl group, an
isopropyl group, a butyl group, an isobutyl group, a sec-butyl
group, a tert-butyl group, a pentyl group, an isopentyl group, a
neopentyl group, a tert-pentyl group, a 1-methylbutyl group, a
2-methylbutyl group, a 1,2-dimethylpropyl group, a 1-ethylpropyl
group, a hexyl group, an isohexyl group, a 1-methylpentyl group, a
2-methylpentyl group, a 3-methylpentyl group, a 1,1-dimethylbutyl
group, a 1,2-dimethylbutyl group, a 2,2-dimethylbutyl group, a 1
ethylbutyl group, a 1,1,2-trimethylpropyl group, a
1,2,2-trimethylpropyl group, a 1-ethyl-2-methylpropyl group, and a
1-ethyl-1-methylpropyl group.
[0026] Examples of the cycloalkyl group having 3 to 8 carbon atoms
include a cyclopropyl group, a cyclobutyl group, a cyclopentyl
group, and a cyclohexyl group.
[0027] Examples of the aryl group include a phenyl group, a
naphthyl group, a 2-methylphenyl group, a 3-methylphenyl group, a
4-methylphenyl group, a 4-vinylphenyl group, and a
3-isopropylphenyl group.
[0028] Examples of the aralkyl group having 7 to 12 carbon atoms
include a benzyl group, a diphenylmethyl group, and a
naphthylmethyl group.
[0029] When at least one of R.sup.1, R.sup.2, and R.sup.3 is a
group having a polymerizable double bond as described above, curing
can be conducted by an active energy ray or the like. Due to two
curing mechanisms, namely, an active energy ray and an improved
crosslinking density of a coating film caused by a condensation
reaction of a silanol group and/or a hydrolyzable silyl group, a
cured product having higher wear resistance, acid resistance,
alkali resistance, and solvent resistance can be formed and thus
the dispersant is suitable for use in paints for building exteriors
and for use with readily thermally deformable substrates, such as
plastic substrates, to which thermosetting resin compositions are
not suitable.
[0030] Two or more groups having a polymerizable double bond are
preferably present in a polysiloxane segment (a1) and more
preferably 3 to 200 and most preferably 3 to 50 such groups are
present since a coating film having a higher wear resistance can be
obtained. In particular, as long as the polymerizable double bond
content in the polysiloxane segment (a1) is 3 to 35 wt %, desired
wear resistance can be obtained. Note that a polymerizable double
bond referred here is a general name for groups that can undergo
free-radical propagation reaction selected from among a vinyl
group, a vinylidene group, and a vinylene group. The polymerizable
double bond content is in terms of percent by weight of the vinyl,
vinylene, or vinylene group in the polysiloxane segment.
[0031] All known functional groups each containing a vinyl group, a
vinylidene group, or a vinylene group can be used as the group
having a polymerizable double bond. Among these, a (meth)acryloyl
group represented by --R.sup.4--C(CH.sub.3).dbd.CH.sub.2 or
--R.sup.4--O--CO--C(CH.sub.3).dbd.CH.sub.2 exhibits high reactivity
during UV curing and good compatibility with the vinyl-based
polymer segment (a2) described below.
[0032] The structural unit represented by general formula (1)
and/or general formula (2) described above are three-dimensional
network polysiloxane structural unit in which two or three of
dangling bonds of the silicon atom are involved in crosslinking.
Although a three-dimensional network structure is formed, the
network structure is not dense and thus gelation or the like does
not occur and the storage stability is improved.
(Compound Resin (A)--Silanol Group and/or Hydrolyzable Silyl
Group)
[0033] In the present invention, a silanol group refers to a
silicon-containing group that has a hydroxyl group directly bonded
to a silicon atom. The silanol group is preferably a silanol group
generated when a hydrogen atom is bonded to the oxygen atom having
a dangling bond in the structural units represented by general
formula (1) and/or general formula (2) above.
[0034] In the present invention, a hydrolyzable silyl group refers
to a silicon-containing group having a hydrolyzable group directly
bonded to a silicon atom. Examples thereof include groups
represented by general formula (4):
##STR00003##
(In general formula (4), R.sup.5 represents a monovalent organic
group such as an alkyl group, an aryl group, or an aralkyl group
and R.sup.6 represents a hydrolyzable group selected from the group
consisting of a halogen atom, an alkoxy group, an acyloxy group, a
phenoxy group, an aryloxy group, a mercapto group, an amino group,
an amide group, an aminoxy group, an iminoxy group, and an
alkenyloxy group. Moreover, b represents an integer of 0 to 2.)
[0035] Examples of the alkyl group for R.sup.5 include a methyl
group, an ethyl group, a propyl group, an isopropyl group, a butyl
group, an isobutyl group, a sec-butyl group, a tert-butyl group, a
pentyl group, an isopentyl group, a neopentyl group, a tert-pentyl
group, a 1-methylbutyl group, a 2-methylbutyl group, a
1,2-dimethylpropyl group, a 1-ethylpropyl group, a hexyl group, an
isohexyl group, a 1-methylpentyl group, a 2-methylpentyl group, a
3-methylpentyl group, a 1,1-dimethylbutyl group, a
1,2-dimethylbutyl group, a 2,2-dimethylbutyl group, a 1-ethylbutyl
group, a 1,1,2-trimethylpropyl group, a 1,2,2-trimethylpropyl
group, a 1-ethyl-2-methylpropyl group, and a 1-ethyl-1-methylpropyl
group.
[0036] Examples of the aryl group include a phenyl group, a
naphthyl group, a 2-methylphenyl group, a 3-methylphenyl group, a
4-methylphenyl group, a 4-vinylphenyl group, and a
3-isopropylphenyl group.
[0037] Examples of the aralkyl group include a benzyl group, a
diphenylmethyl group, and a naphthylmethyl group.
[0038] Examples of the halogen atom for R.sup.6 include a fluorine
atom, a chlorine atom, a bromine atom, and an iodine atom.
[0039] Examples of the alkoxy group include a methoxy group, an
ethoxy group, a propoxy group, an isopropoxy group, a butoxy group,
a sec-butoxy group, and a tert-butoxy group.
[0040] Examples of the acyloxy group include formyloxy, acetoxy,
propanoyloxy, butanoyloxy, pivaloyloxy, pentanoyloxy,
phenylacetoxy, acetoacetoxy, benzoyloxy, and naphthoyloxy.
[0041] Examples of the aryloxy group include phenyloxy and
naphthyloxy.
[0042] Examples of the alkenyloxy group include a vinyloxy group,
an allyloxy group, a 1-propenyloxy group, an isopropenyloxy group,
a 2-butenyloxy group, a 3-butenyloxy group, a 2-pentenyloxy group,
a 3-methyl-3-butenyloxy group, and a 2-hexenyloxy group.
[0043] When the hydrolyzable group represented by R.sup.6 is
hydrolyzed, the hydrolyzable silyl group represented by general
formula (4) forms a silanol group. Among these, a methoxy group and
an ethoxy group are preferred since they have high
hydrolyzability.
[0044] In particular, the hydrolyzable silyl group is preferably a
hydrolyzable silyl group in which the oxygen atom having a dangling
bond in the structural unit represented by general formula (1)
and/or general formula (2) is bonded to or substituted with the
hydrolyzable group described above.
[0045] Regarding the silanol group and the hydrolyzable silyl group
described above, a hydrolytic condensation reaction proceeds among
the hydroxyl group in the silanol group and the hydrolyzable group
in the hydrolyzable silyl group; thus, the crosslinking density of
the polysiloxane structure of a cured product obtained is increased
and a cured product having excellent solvent resistance or the like
can be formed.
[0046] They are also used in bonding the polysiloxane segment (a1)
that contains a silanol group and/or a hydrolyzable silyl group and
the vinyl-based polymer segment (a2) described below through a bond
represented by general formula (3).
[0047] Examples of the polysiloxane segment (a1) having a structure
in which at least one of R.sup.1, R.sup.2, and R.sup.3 is a group
having a polymerizable double bond include the following
structures:
##STR00004## ##STR00005##
[0048] In the present invention, the polysiloxane segment (a1) is
preferably contained in an amount of 10 to 90 wt % relative to the
compound resin (A) which is the main component of the inorganic
fine particle dispersant. As a result, an antifouling property,
wear resistance, and weatherability can be achieved.
(Compound Resin (A)--Vinyl-Based Polymer Segment (a2))
[0049] A vinyl-based polymer segment (a2) in the present invention
is a vinyl polymer segment such as an acryl-based polymer, a
fluoroolefin-based polymer, a vinyl ester-based polymer, an
aromatic vinyl-based polymer, or a polyolefin-based polymer. These
may be appropriately selected according to the usage.
[0050] The acryl-based polymer segment is obtained by
polymerization or copolymerization of common (meth)acrylic
monomers. The (meth)acrylic monomers are not particularly limited
and vinyl monomers can also be copolymerized. Examples of the
monomers include alkyl(meth)acrylates each having an alkyl group
with 1 to 22 carbon atoms such as methyl(meth)acrylate,
ethyl(meth)acrylate, n-propyl(meth)acrylate, n-butyl(meth)acrylate,
isobutyl(meth)acrylate, tert-butyl(meth)acrylate,
2-ethylhexyl(meth)acrylate, and lauryl(meth)acrylate;
aralkyl(meth)acrylates such as benzyl(meth)acrylate and
2-phenylethyl(meth)acrylate; cycloalkyl(meth)acrylates such as
cyclohexyl(meth)acrylate and isobornyl(meth)acrylate;
.omega.-alkoxyalkyl(meth)acrylates such as
2-methoxyethyl(meth)acrylate and 4-methoxybutyl(meth)acrylate;
carboxylic acid vinyl esters such as vinyl acetates, vinyl
propionate, vinyl pivalate, and vinyl benzoate; alkyl esters of
crotonic acid such as methyl crotonate and ethyl crotonate; dialkyl
esters of unsaturated dibasic acids such as dimethyl maleate,
di-n-butyl maleate, dimethyl fumarate, and dimethyl itaconate;
.alpha.-olefins such as ethylene and propylene; fluoroolefins such
as vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene,
and chlorotrifluoroethylene; alkyl vinyl ethers such as ethyl vinyl
ether and n-butylvinyl ether; cycloalkyl vinyl ethers such as
cyclopentyl vinyl ether and cyclohexyl vinyl ether; and tertiary
amide-containing monomers such as N,N-dimethyl(meth)acrylamide,
N-(meth)acryloylmorpholine, N-(meth)acryloylpyrrolidine, and
N-vinylpyrrolidone.
[0051] There is no limit on the polymerization method, the solvent,
and the polymerization initiator used in copolymerizing the
monomers described above and the vinyl-based polymer segment (a2)
can be obtained by a known method. For example, a vinyl-based
polymer segment (a2) can be obtained by any of various
polymerization processes such as bulk radical polymerization,
solution radical polymerization, and non-aqueous dispersion radical
polymerization by using a polymerization initiator such as
2,2'-azobis(isobutyronitrile),
2,2'-azobis(2,4-dimethylvaleronitrile),
2,2'-azobis(2-methylbutyronitrile), tert-butylperoxy pivalate,
tert-butylperoxy benzoate, tert-butylperoxy-2-ethyl hexanoate,
di-tert-butyl peroxide, cumene hydroperoxide, or diisopropyl peroxy
carbonate.
[0052] The number-average molecular weight (hereinafter referred to
as Mn) of the vinyl-based polymer segment (a2) is preferably in the
range of 500 to 200,000 since thickening and gelation can be
prevented during production of the compound resin (A) and
durability can be improved. Mn is more preferably in the range of
700 to 100,000 and yet more preferably in the range of 1,000 to
50,000 since a satisfactory cured film can be formed on a
substrate.
[0053] The vinyl-based polymer segment (a2) has a silanol group
and/or a hydrolyzable silyl group directly bonded to the carbon
atom in the vinyl-based polymer segment (a2) in order to form the
compound resin (A) in which the vinyl-based polymer segment (a2) is
bonded to the polysiloxane segment (a1) through a bond represented
by general formula (3). The silanol group and/or hydrolyzable silyl
group is rarely present in the vinyl-based polymer segment (a2) of
the resulting final product, i.e., the compound resin (A), since
these groups form the bond represented by general formula (3)
during production of the compound resin (A) described below.
However, the silanol group and/or the hydrolyzable silyl group may
remain in the vinyl-based polymer segment (a2). During the
formation of a coating film by a curing reaction of the group
having a polymerizable double bond described above, the hydrolytic
condensation reaction proceeds between the hydroxyl groups in the
silanol group or the hydrolyzable groups in the hydrolyzable silyl
group simultaneously with the curing reaction. Thus, the
crosslinking density of the resulting cured product, i.e., the
polysiloxane structure, is increased and a cured product having
high solvent resistance and the like can be formed.
[0054] Specifically, a vinyl-based polymer segment (a2) having a
silanol group and/or a hydrolyzable silyl group directly bonded to
a carbon atom is obtained by copolymerizing the common monomer
described above and a vinyl-based monomer containing a silanol
group and/or a hydrolyzable silyl group directly bonded to a carbon
bond.
[0055] Examples of the silanol group and/or the hydrolyzable silyl
group directly bonded to a carbon atom include
vinyltrimethoxysilane, vinyltriethoxysilane,
vinylmethyldimethoxysilane, vinyltri(2-methoxyethoxy)silane,
vinyltriacetoxysilane, vinyltrichlorosilane,
2-trimethoxysilylethylvinyl ether,
3-(meth)acryloyloxypropyltrimethoxysilane, 3
(meth)acryloyloxypropyltriethoxysilane,
3-(meth)acryloyloxypropylmethyldimethoxysilane, and
3-(meth)acryloyloxypropyltrichlorosilane. Among these,
vinyltrimethoxysilane and 3-(meth)acryloyloxypropyltrimethoxysilane
are preferred since they allow smooth hydrolysis and by-products
after the reaction can be easily removed.
[0056] When a reactive compound such as a polyisocyanate described
below is to be contained, the vinyl-based polymer segment (a2)
preferably has a reactive functional group such as an alcoholic
hydroxyl group. For example, the vinyl-based polymer segment (a2)
having an alcoholic hydroxyl group can be obtained by
copolymerization with a (meth)acrylic monomer having an alcoholic
hydroxyl group. Specific examples of the (meth)acrylic monomer
having an alcoholic hydroxyl group include various hydroxyl alkyl
esters of .alpha.- and .beta.-ethylenically unsaturated carboxylic
acids and their adducts with .epsilon.-caprolactone, such as
2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate,
3-hydroxypropyl(meth)acrylate, 2-hydroxybutyl(meth)acrylate,
3-hydroxybutyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate,
3-chloro-2-hydroxypropyl(meth)acrylate, di-2-hydroxyethyl fumarate,
mono-2-hydroxyethyl monobutyl fumarate, polyethylene glycol
mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, and
"PLACCEL FM or PLACCEL FA" [caprolactone-added monomer produced by
Daicel Corporation].
[0057] Among these, 2-hydroxyethyl(meth)acrylate is preferred for
its ease of reaction.
[0058] The amount of the alcoholic hydroxyl groups is preferably
appropriately determined by calculation based on the amount of the
polyisocyanate added described below.
(Method for Producing Compound Resin (A))
[0059] In particular, the compound resin (A) used in the present
invention is produced by any of (Method 1) to (Method 3) described
below.
(Method 1) The common (meth)acrylic monomer and the like and a
vinyl-based monomer containing a silanol group and/or a
hydrolyzable silyl group directly bonded to the carbon bond are
copolymerized so as to obtain a vinyl-based polymer segment (a2)
having a silanol group and/or a hydrolyzable silyl group directly
bonded to the carbon bond. The vinyl-based polymer segment (a2) is
mixed with a silane compound to conduct a hydrolytic condensation
reaction. If there is a group to be introduced, a silane compound
having a group to be introduced is used. For example, when an aryl
group is to be introduced, an appropriate silane compound having an
aryl group and a silanol group and/or a hydrolyzable silyl group
may be used. In order to introduce a group having a polymerizable
double bond, a silane compound having a group having a
polymerizable double bond and a silanol group and/or hydrolyzable
silyl group may be used.
[0060] According to this method, a hydrolytic condensation reaction
occurs between the silanol group or hydrolyzable silyl group of the
silane compound and the silanol group and/or the hydrolyzable silyl
group of the vinyl-based polymer segment (a2) having the silanol
group and/or the hydrolyzable silyl group directly bonded to the
carbon bond so as to form a polysiloxane segment (a1) and to obtain
a compound resin (A) in which the polysiloxane segment (a1) is
compounded with the vinyl-based polymer segment (a2) through the
bond represented by general formula (3) above.
(Method 2) A vinyl-based polymer segment (a2) having a silanol
group and/or a hydrolyzable silyl group directly bonded to a carbon
bond is obtained as in Method 1.
[0061] A silane compound (when there is a group to be introduced, a
silane compound having the group to be introduced is used) is
subjected to a hydrolytic condensation reaction to obtain a
polysiloxane segment (a1). Then a hydrolytic condensation reaction
is induced between the silanol group and/or the hydrolyzable silyl
group of the vinyl-based polymer segment (a2) and the silanol group
and/or the hydrolyzable silyl group of the polysiloxane segment
(a1).
(Method 3) A vinyl-based polymer segment (a2) having a silanol
group and/or a hydrolyzable silyl group directly bonded to a carbon
bond is obtained as in Method 1. A polysiloxane segment (a1) is
obtained as in Method 2. Then a hydrolytic condensation reaction is
induced by mixing a silane compound or the like that has a group to
be introduced as needed.
[0062] Examples of the silane compound that has both a group having
a polymerizable double bond and a silanol group and/or a
hydrolyzable silyl group used in introducing the group having a
polymerizable double bond include vinyltrimethoxysilane,
vinyltriethoxysilane, vinylmethyldimethoxysilane,
vinyltri(2-methoxyethoxy)silane, vinyltriacetoxysilane,
vinyltrichlorosilane, 2-trimethoxysilylethylvinyl ether,
3-(meth)acryloyloxypropyltrimethoxysilane, 3
(meth)acryloyloxypropyltriethoxysilane,
3-(meth)acryloyloxypropylmethyldimethoxysilane, and
3-(meth)acryloyloxypropyltrichlorosilane. Among these,
vinyltrimethoxysilane and 3-(meth)acryloyloxypropyltrimethoxysilane
are preferred since the hydrolytic reaction can be smoothly carried
out and the by-products after the reaction can be easily
removed.
[0063] Examples of the common silane compound used in (Method 1) to
(Method 3) above include various organotrialkoxysilanes such as
methyltrimethoxysilane, methyltriethoxysilane,
methyltri-n-butoxysilane, ethyltrimethoxysilane,
n-propyltrimethoxysilane, iso-butyltrimethoxysilane, and
cyclohexyltrimethoxysilane; various diorganodialkoxysilanes such as
dimethyldimethoxysilane, dimethyldiethoxysilane,
dimethyldi-n-butoxysilane, dimethyldimethoxysilane, and
methylcyclohexyldimethoxysilane; and chlorosilanes such as
methyltrichlorosilane, ethyltrichlorosilane, vinyltrichlorosilane,
dimethyldichlorosilane, and dimethyldichlorosilane. Among these,
organotrialkoxysilanes and diorganodialkoxysilanes are preferred
since the hydrolytic reaction can be smoothly carried out and the
by-products after the reaction can be easily removed.
[0064] Tetrafunctional alkoxysilane compounds and partially
hydrolyzed condensates of the tetrafunctional alkoxysilane
compounds, such as tetramethoxysilane, tetraethoxysilane, and
tetra-n-propoxysilane, can be used in addition as long as the
effects of the present invention are not impaired. When a
tetrafunctional alkoxysilane compound or a partially hydrolyzed
condensate thereof is used in addition, the number of the silicon
atoms of the tetrafunctional alkoxysilane compound is preferably
not over 20 mol % relative to all silicon atoms in the polysiloxane
segment (a1).
[0065] A metal alkoxide compound of boron, titanium, zirconium,
aluminum, or the like, other than the silicon atom may be used in
combination with the silane compound as long as the effects of the
present invention are not impaired. For example, the number of the
metal atoms of the metal alkoxide compound relative to the number
of all silicon atoms in the polysiloxane segment (a1) is preferably
not over 25 mol %.
[0066] The hydrolytic condensation reaction in the (Method 1) to
(Method 3) described above refers to a condensation reaction that
occurs between hydroxyl groups formed by hydrolysis of some of the
hydrolyzable groups due to influence of water and the like or
between the hydroxyl groups and hydrolyzable groups. The hydrolytic
condensation reaction can be carried out by a known method but a
method with which the reaction is proceeded by supplying water and
a catalyst in the production process described above is convenient
and is thus preferred.
[0067] Examples of the catalyst used include inorganic acids such
as hydrochloric acid, sulfuric acid, and phosphoric acid; organic
acids such as p-toluene sulfonic acid, monoisopropyl phosphonate,
and acetic acid; inorganic bases such as sodium hydroxide and
potassium hydroxide; titanates such as tetraisopropyl titanate and
tetrabutyl titanate; compounds containing various basic nitrogen
atoms such as 1,8-diazabicyclo[5.4.0]undecene-7 (DBU),
1,5-diazabicyclo[4.3.0]nonene-5 (DBN),
1,4-diazabicyclo[2.2.2]octane (DABCO), tri-n-butylamine,
dimethylbenzylamine, monoethanolamine, imidazole, and
1-methylimidazole; quaternary ammonium salts having a chloride, a
bromide, a carboxylate, or a hydroxide as the counterion, such as
tetramethyl ammonium salts, tetrabutyl ammonium salts, and
dilauryldimethyl ammonium salts; and tin carboxylic acid salts such
as dibutyltin diacetate, dibutyltin dioctate, dibutyltin dilaurate,
dibutyltin diacetylacetonate, tin octylate, and tin stearate. These
catalysts may be used alone or in combination.
[0068] The amount of the catalyst added is not limited. In general,
the catalyst is preferably used in an amount in the range of 0.0001
to 10 wt %, more preferably 0.0005 to 3 wt %, and most preferably
0.001 to 1 wt % relative to the total amount of the compounds
having a silanol group or a hydrolyzable silyl group.
[0069] The amount of water supplied is preferably 0.05 mol or more,
more preferably 0.1 mol or more and particularly preferably 0.5 mol
or more per mole of silanol groups or hydrolyzable silyl groups of
the compounds having silanol groups or hydrolyzable silyl
groups.
[0070] These catalysts and water may be added in batch or
sequentially. A mixture of a catalyst and water prepared in advance
may also be supplied.
[0071] The reaction temperature during the hydrolytic condensation
reaction in (Method 1) to (Method 3) above is within the range of
0.degree. C. to 150.degree. C. and preferably 20.degree. C. to
100.degree. C. The condition of the reaction pressure may be any,
e.g., the pressure may be normal, high, or low. Alcohols and water
which are by-products of the hydrolytic condensation reaction may
be removed by distillation or the like as needed.
[0072] The feed ratios of the compounds used in (Method 1) to
(Method 3) described above are appropriately selected according to
the structure of the compound resin (A) desirably used in the
present invention. In particular, the compound resin (A) is
preferably obtained so that the polysiloxane segment (a1) content
is 10 to 90 wt % and more preferably 30 to 75 wt % since the
durability of the coating film obtained therefrom is high.
[0073] An example of a specific method for compounding a
polysiloxane segment and a vinyl-based polymer into a block
structure in the (Method 1) to (Method 3) above is a method with
which a vinyl-based polymer segment having a silanol group and/or a
hydrolyzable silyl group only at one or both termini of a polymer
chain is used as an intermediate and, in (Method 1) for example, a
silane compound is mixed with the vinyl-based polymer segment to
conduct a hydrolytic condensation reaction.
[0074] An example of a specific method for grafting a polysiloxane
segment to a vinyl-based polymer segment in
[0075] (Method 1) to (Method 3) above is a method with which a
vinyl-based polymer segment having a silanol group and/or a
hydrolyzable silyl group randomly distributed in the main chain of
the vinyl-based polymer segment is used as an intermediate and, in
(Method 2) for example, a hydrolytic condensation reaction is
carried out between the silane compound and the silanol group
and/or the hydrolyzable silyl group of the vinyl-based polymer
segment.
(Inorganic Fine Particles)
[0076] Inorganic fine particles used in the present invention are
preferably silica fine particles or titanium oxide fine particles
since the effects of the present invention can be maximized. Since
the compound resin (A) used in the present invention has a
polysiloxane segment, the compound resin (A) is highly compatible
with the inorganic components and inorganic fine particles can be
smoothly dispersed even when the amount added exceeds 50 wt %.
After dispersing, the inorganic fine particles do not precipitate
or harden but exhibit long-term storage stability. The vinyl-based
polymer segment is highly compatible with reactive compounds and
thus an inorganic fine particle dispersion liquid prepared by using
an inorganic fine particle dispersant containing the compound resin
(A) as an essential component satisfactorily disperses in a
reactive compound and gives a highly stable dispersion.
[0077] Silica fine particles are not particularly limited and known
silica fine particles such as powder silica and colloidal silica
can be used. Examples of commercially available powder silica fine
particles include AEROSIL 50 and 200 produced by Aerosil Japan,
SILDEX H31, H32, H51, H52, H121, and H122 produced by Asahi Glass
Co., Ltd., E220A and E220 produced by Nippon Silica Kogyo K.K.,
SYLYSIA 470 produced by Fuji Silysia Chemical Ltd., and SG flake
produced by Nippon Sheet Glass Co. Ltd.
[0078] Examples of commercially available colloidal silica include
methanol silica sol, IPA-ST, MEK-ST, NBA-ST, XBA-ST, DMAC-ST,
ST-UP, ST-OUP, ST-20, ST-40, ST-C, ST-N, ST-O, ST-50, and ST-OL
produced by Nissan Chemical Industries, Ltd.
[0079] Silica fine particles having dispersibility improved by a
known method may also be used. Examples of the silica fine
particles having improved dispersibility include those obtained by
surface-treating silica fine particles with a reactive silane
coupling agent having a hydrophobic group or by modification with a
compound having a (meth)acryloyl group. Examples of commercially
available powder silica modified with a compound having a
(meth)acryloyl group include AEROSIL RM 50 and R711 produced by
Aerosil Japan, and examples of commercially available colloidal
silica modified with a compound having an acryloyl group include
MIBK-SD produced by Nissan Chemical Industries, Ltd.
[0080] The shape of the silica fine particles is not particularly
limited and may be spherical, hollow, porous, rod-like, plate-like,
fibrous, or irregularly shaped. An example of commercially
available hollow silica fine particles is SiliNax produced by
Nittetsu Mining Co., Ltd.
[0081] The primary particle size is preferably in the range of 5 to
200 nm. If the size is less than 5 nm, inorganic fine particles do
not sufficiently disperse in the dispersion. At a size exceeding
200 nm, the cure product may not retain sufficient strength.
[0082] Not only extenders but also UV light responsive
photocatalysts can be used as the titanium oxide fine particles.
For example, anatase-type titanium oxide, rutile-type titanium
oxide, and brookite-type titanium oxide can be used. Furthermore,
particles designed to be responsive to visible light by doping
crystal structures of titanium oxide with different elements can
also be used. Preferred examples of the elements used as a dopant
for titanium oxide include anion elements such as nitrogen, sulfur,
carbon, fluorine, and phosphorus and cation elements such as
chromium, iron, cobalt, and manganese. As for the form, a powder or
a sol or slurry dispersed in an organic solvent or water may be
used. Examples of commercially available powder titanium oxide fine
particles include AEROSIL P-25 produced by Aerosil Japan, and
ATM-100 produced by Tayca Corporation. Examples of commercially
available slurry of titanium oxide fine particles include TKD-701
produced by Tayca Corporation.
[0083] In the inorganic fine particle dispersion liquid of the
present invention, 5 to 90 wt % of inorganic fine particles can be
blended relative to the solid content of the inorganic fine
particle dispersion liquid. In particular, in order to impart wear
resistance, the amount of the silica fine particles added is
preferably 5 to 80 wt % and more preferably 10 to 70 wt % relative
to the total solid content of the inorganic fine particle
dispersion liquid of the present invention. At a content of 5 wt %
or more, wear resistance is enhanced. However, at a content of 80
wt % or more, the cured product may not retain sufficient
strength.
[0084] In order to impart photocatalytic activity, the amount of
the titanium oxide fine particles relative to the total solid
content of the inorganic fine particle dispersion liquid of the
present invention is preferably 5 to 80 wt % and more preferably 30
to 70 wt %. At less than 5 wt %, the photocatalytic activity tends
to be poor and at exceeding 80 wt %, the cured product may not
retain sufficient strength.
[0085] The particle size of the inorganic particles dispersed in
the cured film is not particularly limited but is preferably 5 to
200 nm and more preferably 10 nm to 100 nm. Here, "particle size"
is measured by using a scanning electron microscope (TEM) or the
like.
(Inorganic Fine Particle Dispersion Liquid)
[0086] An inorganic fine particle dispersion liquid in the present
invention is a dispersion liquid that contains inorganic fine
particles and an inorganic fine particle dispersant.
[0087] The method for dispersing inorganic fine particles by using
the inorganic fine particle dispersant is not particularly limited
and any known dispersion method may be employed. Examples of the
mechanical means include a disper, a dispersion machine equipped
with a stirring blade such as a turbine blade, a paint shaker, a
roll mill, a ball mill, an attritor, a sand mill, and a bead mill.
In order to produce an inorganic fine particle dispersion so that
the resulting dispersion is used in a coating agent or the like,
dispersing is preferably conducted with a bead mill that uses
dispersion media such as glass beads and zirconia beads from the
viewpoint of coatability, coating stability, transparency of cured
products, etc.
[0088] Examples of the bead mill include Star Mill produced by
Ashizawa Finetech Ltd.; MSC-MILL, SC-MILL, and attritor MA01SC
produced by Mitsui Mining Co., Ltd.; nano grain mill, pico grain
mill, pure grain mill, mechagaper grain mill, cera power grain
mill, dual grain mill, AD mill, twin AD mill, basket mill, and twin
basket mill produced by Asada Iron Works Co., Ltd.; and aspek mill,
ultra aspek mill, and super aspek mill produced by Kotobuki
Industries Co., Ltd. Among these, ultra aspek mill is
preferred.
[0089] An inorganic fine particle dispersion liquid is
preliminarily prepared by dispersing the compound resin (A) and
inorganic fine particles used in the present invention by using a
bead mill, a roll mill, or the like so that the inorganic fine
particles are blended at a high concentration and the inorganic
fine particle dispersion liquid is dispersed in a reactive
compound, e.g., a reactive diluent such as polyisocyanate and an
active energy ray-curable monomer. In this manner, a paint can be
formed efficiently without risk of gelation. When the concentration
of the dispersed inorganic fine particles here is within the range
of 5 to 90 wt % relative to the total solid content of the
inorganic fine particle dispersion liquid, a dispersion liquid
having excellent storage stability capable of preventing
precipitation, solidification, and the like of inorganic fine
particles can be obtained.
[0090] The method for dispersing inorganic fine particles may be
any. For example, 10 to 95 parts by weight of the compound resin
(A) prepared by any of Methods 1 to 3 described above according to
the present invention and 90 to 5 parts by weight of inorganic fine
particles may be diluted with a dispersion medium so that the total
concentration of the compound resin (A) and the inorganic fine
particles is 1 to 50 wt % and the resulting mixture may be
dispersed through mechanical means.
[0091] The average particle size of inorganic particles in the
dispersion liquid prepared as such is not particularly limited but
is preferably 5 to 200 nm and more preferably 10 nm to 100 nm.
Here, the "average particle size" is calculated by using a particle
size distribution analyzer that employs a dynamic light scattering
method (ELS-Z produced by Otsuka Electronics Co., Ltd., cell width:
1 cm, diluting solvent: MEK) or the like.
[0092] A dispersion medium may be used in the inorganic fine
particle dispersion liquid of the present invention to adjust the
solid content and viscosity of the dispersion liquid.
[0093] The dispersion medium may be any liquid medium that does not
impair the effects of the present invention and examples thereof
include various organic solvents and liquid organic polymers.
[0094] Examples of the organic solvents include ketones such as
acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone
(MIBK), cyclic ethers such as tetrahydrofuran (THF) and dioxolane,
esters such as methyl acetate, ethyl acetate, and butyl acetate,
aromatic compounds such as toluene and xylene, and alcohols such as
carbitol, cellosolve, methanol, isopropanol, butanol, and propylene
glycol monomethyl ether. These may be used alone or in combination.
Among these, methyl ethyl ketone is preferred from the viewpoints
of volatility during coating and recovery of the solvent.
[0095] The liquid organic polymer mentioned above is a liquid
organic polymer not directly contributing to curing reaction.
Examples thereof include carboxyl-containing polymer modified
product (Flowlen G-900 and NC-500 produced by Kyoeisha Chemical
Co., Ltd.), acryl polymers (Flowlen WK-20 produced by Kyoeisha
Chemical Co., Ltd.), amine salts of specially modified phosphates
(HIPLAAD ED-251 produced by Kusumoto Chemicals, Ltd.), and modified
acryl-based block copolymers (DISPER BYK 2000 produced by
BYK-Chemie GmbH).
(Inorganic Fine Particle Dispersion)
[0096] In the present invention, an inorganic fine particle
dispersion refers to a dispersion that contains inorganic fine
particles, an inorganic fine particle dispersant, and a reactive
compound.
(Reactive Compound)
[0097] A polymer or monomer that has a reactive group directly
contributing to a curing reaction with the compound resin (A) can
be used as the reactive compound that can be used in the present
invention. In particular, a reactive diluent such as a
polyisocyanate and an active energy ray-curable monomer is
preferred.
[0098] According to an inorganic fine particle dispersion that uses
a reactive compound and the compound resin (A) into which a
reactive functional group is introduced, the compound resin (A)
serving as a dispersant and the reactive diluent undergo
three-dimensional crosslinking and thus the problems common to the
practice of using dispersants, i.e., bleeding out of the dispersant
and plasticization of cured products due to addition of
dispersants, can be avoided, and a cured product that has excellent
weatherability and wear resistance can be obtained.
[0099] When a polyisocyanate is used as the reactive compound, the
vinyl-based polymer segment (a2) in the compound resin (A)
preferably contains an alcoholic hydroxyl group. The polyisocyanate
content relative to the total amount of the inorganic fine particle
dispersion of the present invention is preferably 5 to 50 wt %.
When the polyisocyanate is contained within this range, a cured
product having particularly excellent long-term outdoor
weatherability (crack resistance to be more specific) is obtained.
This is presumably because hydroxyl groups (hydroxyl groups in the
vinyl-based polymer segment (a2) described above or hydroxyl groups
in the active energy ray-curable monomer having alcoholic hydroxyl
groups described below) in the system react with the polyisocyanate
to give urethane bonds, which are soft segments, and this leads to
reducing the stress concentration caused by curing through
polymerizable double bonds.
[0100] The polyisocyanate to be used is not particularly limited
and a known polyisocyanate can be used. However, aromatic
diisocyanates such as tolylene diisocyanate and
diphenylmethane-4,4'-diisocyanate, and polyisocyanates whose main
raw material is aralkyl diisocyanates such as meta-xylylene
diisocyanate and
.alpha.,.alpha.,.alpha.',.alpha.'-tetramethyl-meta-xylylene
diisocyanate are preferably used in as small quantities as possible
since yellowing of cured coatings occurs when the cured coatings
are exposed outdoors for long time.
[0101] From the viewpoint of long-term outdoor use, the
polyisocyanate used in the present invention is preferably an
aliphatic polyisocyanate mainly composed of an aliphatic
diisocyanate. Examples of the aliphatic diisocyanate include
tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate,
1,6-hexamethylene diisocyanate (hereinafter referred to as "HDI"),
2,2,4-(or 2,4,4-trimethyl-1,6-hexamethylene diisocyanate, lysine
isocyanate, isophorone diisocyanate, hydrogenated xylene
diisocyanate, hydrogenated diphenyl methane diisocyanate,
1,4-diisocyanate cyclohexane,
1,3-bis(diisocyanatemethyl)cyclohexane, and
4,4'-dicyclohexylmethane diisocyanate. Among these, HDI is
particularly preferred form the viewpoints of crack resistance and
cost.
[0102] Examples of the aliphatic polyisocyanate obtained from an
aliphatic diisocyanate include allophanate-type polyisocyanates,
biuret-type polyisocyanates, adduct-type polyisocyanates, and
isocyanurate-type polyisocyanates. All of these are preferred for
use.
[0103] A block polyisocyanate compound in which blocks are formed
by using any of various types of block agents may be used as the
polyisocyanate. Examples of the block agent include alcohols such
as methanol, ethanol, and lactates; phenolic hydroxyl
group-containing compounds such as phenol and salicylates; amides
such as .epsilon.-caprolactam and 2-pyrrolidone; oximes such as
acetone oxime and methyl ethyl ketoxime; and active methylene
compounds such as methyl acetoacetate, ethyl acetoacetate, and
acetyl acetone.
[0104] The isocyanate group content in the polyisocyanate is
preferably 3 to 30 wt % from the viewpoints of crack resistance and
wear resistance of a cured coating obtained from a paint. When the
isocyanate group content in the polyisocyanate is more than 30%,
the molecular weight of the polyisocyanate is decreased and the
crack resistance due to stress relaxation may not be exhibited.
[0105] The reaction between the polyisocyanate and hydroxyl groups
in the system (these hydroxyl groups are hydroxyl groups in the
vinyl-based polymer segment (a2) or hydroxyl groups in the active
energy ray-curable monomer having alcoholic hydroxyl groups
described below) does not require heating or the like and the
reaction gradually proceeds when the system is left at room
temperature. If needed, the system may be heated at 80.degree. C.
for several minutes to several hours (20 minutes to 4 hours) so as
to accelerate the reaction between the alcoholic hydroxyl groups
and the isocyanate. In such a case, a known urethanation catalyst
may be used as needed. The urethanation catalyst is appropriately
selected according to the desired reaction temperature.
[0106] When an active energy ray-curable monomer is used as the
reactive compound, a multifunctional (meth)acrylate is preferably
contained. The multifunctional (meth)acrylate is not particularly
limited and a known multifunctional (meth)acrylate can be used.
Examples thereof include multifunctional (meth)acrylates having two
or more polymerizable double bonds in a molecule, such as
1,2-ethanediol diacrylate, 1,2-propanediol diacrylate,
1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, dipropylene
glycol diacrylate, neopentyl glycol diacrylate, tripropylene glycol
diacrylate, trimethylolpropane diacrylate, trimethylolpropane
triacrylate, tris(2-acryloyloxy)isocyanurate, pentaerythritol
triacrylate, pentaerythritol tetraacrylate,
di(trimethylolpropane)tetraacrylate,
di(pentaerythritol)pentaacrylate, and di(pentaerythritol)
hexaacrylate. Urethane acrylate, polyester acrylate, epoxy
acrylate, and the like are also examples of the multifunctional
acrylate. These may be used alone or in combination.
[0107] For example, when the polyisocyanate described above is used
in combination, acrylates having hydroxyl groups such as
pentaerythritol triacrylate and dipentaerythritol pentaacrylate are
preferred. In order to further increase the crosslinking density,
use of (meth)acrylates having a high functionality, such as
di(pentaerythritol) pentaacrylate and di(pentaerythritol)
hexaacrylate, is also effective.
[0108] A monofunctional (meth)acrylate can also be used in
combination with the multifunctional (meth)acrylate. Examples
thereof include hydroxyl-group-containing (meth)acrylates such as
hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate,
hydroxybutyl(meth)acrylate, caprolactone-modified
hydroxy(meth)acrylate (e.g., "PLACCEL", trade name, produced by
Daicel Corporation), mono(meth)acrylate of a polyester diol
obtained from phthalic acid and propylene glycol,
mono(meth)acrylate of a polyester diol obtained from succinic acid
and propylene glycol, polyethylene glycol mono(meth)acrylate,
polypropylene glycol mono(meth)acrylate, pentaerythritol
tri(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl
(meth)acrylate, and (meth)acrylate adducts of various epoxy esters;
carboxyl-group-containing vinyl monomers such as (meth)acrylic
acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid;
sulfonic acid group-containing vinyl monomers such as vinyl
sulfonic acid, styrene sulfonic acid, and sulfoethyl(meth)acrylate;
acidic phosphate-based vinyl monomers such as
2-(meth)acryloyloxyethyl acid phosphate, 2 (meth)acryloyloxypropyl
acid phosphate, 2-(meth)acryloyloxy-3-chloro-propyl acid phosphate,
and 2-methacryloyloxyethylphenyl phosphoric acid; and
methylol-group-containing vinyl monomers such as
N-methylol(meth)acrylamide. These may be used alone or in
combination. Considering the reactivity to the isocyanate groups in
the polyfunctional isocyanate (b), the monomer (c) is preferably a
hydroxyl group-containing (meth)acrylic acid ester.
[0109] The amount of the multifunctional acrylate used is
preferably 1 to 85 wt % and more preferably 5 to 80 wt % relative
to the total solid content of the inorganic fine particle
dispersion. When the multifunctional acrylate is used within this
range, physical properties such as hardness of the resulting layer
can be improved.
[0110] As for the method for dispersing the reactive compound in a
dispersion liquid containing the compound resin (A) and the
inorganic fine particles, i.e., the inorganic fine particle
dispersion liquid, dispersing can be smoothly carried out by
stirring by hand or with a known stirring machine such as disper or
a homomixer. When the viscosity is high, a dispersion medium
described above may be appropriately added.
(Inorganic Fine Particle Dispersion--Other Blend Materials)
[0111] The inorganic fine particle dispersion of the present
invention may use a dispersion medium to adjust the solid content
and viscosity of the dispersion liquid. The dispersion medium may
be any liquid medium that does not impair the effects of the
present invention and examples thereof include the organic solvents
and liquid organic polymers described above.
[0112] The inorganic fine particle dispersion of the present
invention can be cured by an active energy ray if the compound
resin (A) contains a group having a polymerizable double bond
described above. Examples of the active energy ray include UV light
emitted from light sources such as a xenon lamp, a low-pressure
mercury lamp, a high-pressure mercury lamp, an ultrahigh pressure
mercury lamp, a metal halide lamp, a carbon arc lamp, and a
tungsten lamp, and an electron beam, an .alpha. ray, a .beta. ray,
and a .gamma. ray typically output from a particle accelerator at
20 to 2000 kV. In particular, UV light or an electron beam is
preferably used. UV light is particularly preferable. Examples of
the UV ray source include sunlight, a low-pressure mercury lamp, a
high-pressure mercury lamp, an ultrahigh pressure mercury lamp, a
carbon arc lamp, a metal halide lamp, a xenon lamp, an argon laser,
and a helium cadmium laser. A layer of the inorganic fine particle
dispersion formed by application can be cured by irradiation of a
UV ray having a wavelength of about 180 to 400 nm emitted from any
of these devices. The dose of the UV light is appropriately
selected according to the type and amount of the
photopolymerization initiator used.
[0113] Curing with an active energy ray is particularly effective
when the substrate is composed of a material such as plastic having
low heat resistance. In the case where heat is also used to an
extent that does not adversely affect the substrate, a known heat
source such as hot air or near infrared rays can be used.
[0114] When a UV ray is used to conduct curing, a
photopolymerization initiator is preferably used. A known
photopolymerization initiator may be used. For example, at least
one selected from the group consisting of an acetophenone, a benzyl
ketal, and a benzophenone is preferably used. Examples of the
acetophenone include diethoxy acetophenone,
2-hydroxy-2-methyl-1-phenylpropan-1-one,
1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, and
4-(2-hydroxyethoxyl)phenyl-(2-hydroxy-2-propyl) ketone. Examples of
the benzyl ketal include 1-hydroxycyclohexyl-phenyl ketone and
benzyl dimethyl ketal. Examples of the benzophenone include
benzophenone, and methyl o-benzoylbenzoate. Examples of the benzoin
include benzoin, benzoin methyl ether, and benzoin isopropyl ether.
The photopolymerization initiators (B) may be used alone or in
combination.
[0115] The amount of the photopolymerization initiator (B) is
preferably 1 to 15 wt % and more preferably 2 to 10 wt % relative
to 100 wt % of the compound resin (A).
[0116] When the inorganic fine particle dispersion of the present
invention is to be thermally cured, various catalysts are
preferably selected by considering the reaction temperature,
reaction time, etc., of the reaction of the polymerizable double
bonds in the composition and the urethanation reaction between
alcoholic hydroxyl groups and the isocyanate.
[0117] Moreover, it is possible to additionally use a thermosetting
resin. Examples of the thermosetting resin include vinyl-based
resins, unsaturated polyester resins, polyurethane resins, epoxy
resins, epoxy ester resins, acrylic resins, phenolic resins,
petroleum resins, ketone resins, silicone resins, and modified
resins of the foregoing.
[0118] In addition, if needed, various additives such as an
inorganic pigment, an organic pigment, an extender, a clay mineral,
a wax, a surfactant, a stabilizer, a flow controller, a dye, a
leveling agent, a rheology controller, a silane coupling agent, a
UV absorber, an antioxidant, and a plasticizer can be used.
[0119] The inorganic fine particle dispersion as is can be used as
a paint curable with a UV ray or the like. The inorganic fine
particle dispersion may be blended with an additive such as an
organic pigment or an inorganic pigment to prepare a paint. When
this paint is cured with a UV ray or the like, a cured product such
as a cured coating film or a laminate can be obtained.
[0120] When a cured film is formed by curing the inorganic fine
particle dispersion or paint of the present invention, the
thickness of the cured film is not particularly limited but is
preferably 0.1 to 300 .mu.m from the viewpoint of forming a cured
coating film having long-term outdoor weatherability and excellent
wear resistance. When the thickness of the cured coating film is
less than 0.1 .mu.m, weatherability and the wear resistance cannot
be imparted to the plastic material. If the thickness is more than
300 .mu.m, the interior of the coating film is not sufficiently
irradiated with the UV ray and curing failure may occur.
[0121] A coated product having a cured coating film having
excellent weatherability and wear resistance can be obtained by
applying the inorganic fine particle dispersion or paint of the
present invention containing a photopolymerization initiator and
the like and irradiating the applied dispersion or paint with a UV
ray.
[0122] A cured coating film having coating film properties similar
to when UV irradiation is conducted in the presence of a
photopolymerization initiator can be obtained by irradiation with
an intense energy ray such as an electron beam without using the
initiator.
[0123] Various substrates can be used as the substrate. For
example, a metal substrate, an inorganic substrate, a plastic
substrate, paper, or a wood substrate may be used.
[0124] For example, in order to form a layer formed of the
inorganic fine particle dispersion on a plastic substrate surface,
a coating method is typically employed although the method is not
limited to this. In particular, after applying the inorganic fine
particle dispersion to the plastic substrate surface, the applied
dispersion is irradiated with ultraviolet light. As a result, a
plastic formed body having a cured coating film with excellent
weatherability and wear resistance can be obtained.
[0125] In this case, in order to control rheology, the inorganic
fine particle dispersion is preferably appropriately diluted with a
solvent in addition to containing the additives described above.
Although the solvent is not particularly limited, use of aromatic
hydrocarbons such as toluene and xylene is preferably avoided
considering the working environment in plants during the
production.
[0126] The thickness of the film after coating is also not
particularly limited. From the viewpoint of forming a cured coating
film that has excellent long-term outdoor weatherability and
excellent wear resistance, the thickness if preferably 0.1 to 300
.mu.m. When the thickness of the cured coating film is less than
0.1 .mu.m, weatherability and wear resistance cannot be imparted to
the plastic material. If the thickness is more than 300 m, the
interior of the coating film may not be sufficiently irradiated
with UV light and curing failure may occur.
[0127] Examples of the material for the plastic substrate include
polyolefins such as polyethylene polypropylene, and
ethylene-propylene copolymers; polyesters such as polyethylene
isophthalate, polyethylene terephthalate, polyethylene naphthalate,
and polybutylene terephthalate; polyamides such as nylon 1, nylon
11, nylon 6, nylon 66, and nylon MX-D; styrene-based polymers such
as polystyrene, styrene-butadiene block copolymers,
styrene-acrylonitrile copolymers, and
styrene-butadiene-acrylonitrile copolymers (ABS resin); acrylic
polymers such as polymethyl methacrylate and methyl
methacrylate-ethyl acrylate copolymers; and polycarbonates. The
plastic substrate may be a single layer or have a multilayer
structure including two or more layers. These plastic substrates
may be unstretched, uniaxially stretched, or biaxially
stretched.
[0128] The plastic substrate may contain known additives such as
known an antistatic agent, an antifogging agent, an anti-blocking
agent, a UV absorber, an antioxidant, a photostabilizer, a
nucleating agent, and a lubricant as long as the effects of the
present invention are not obstructed.
[0129] The plastic substrate may have a surface treated by a known
surface treatment in order to further improve the adhesion to the
inorganic fine particle dispersion of the present invention.
Examples of the surface treatment include a corona discharge
treatment, a plasma treatment, a flame plasma treatment, an
electron beam irradiation treatment, and UV light irradiation
treatment. One of these treatments or a combination of two or more
of these treatments may be conducted.
[0130] The substrate may have any shape, for example, a
sheet-shape, a plate-shape, a spherical shape, or a film-shape or
the substrate may be a large building structure or an assembled
structure or formed structure having a complicated shape. The
surface of the substrate may be coated with an undercoat paint or
the like. It is possible to apply the inorganic fine particle
dispersion of the present invention even when the portions coated
as such are deteriorated.
[0131] A known water-soluble or water-dispersible paint or an
organic solvent-type or organic solvent dispersive-type paint or
powder paint can be used as the undercoat paint. In particular,
various types of undercoat paints such as acrylic resin-based
paints, polyester resin-based paints, alkyd resin-based paints,
epoxy resin-based paints, aliphatic acid-modified epoxy resin-based
paints, silicone resin paints, polyurethane resin-based paints,
fluoroolefin-based paints, and amine-modified epoxy resin paints
can be used. The undercoat paint may be a clear paint free of
pigments, an enamel paint containing a pigment, or a metallic paint
containing aluminum flakes or the like.
[0132] A commonly known coating method may be used as the method
for coating the substrate with the inorganic fine particle
dispersion or paint of the present invention. Examples thereof
include a brushing method, a roller coating method, a spray coating
method, a dip coating method, a flow coater method, a roll coater
method, and an electropainting method.
[0133] After the inorganic fine particle dispersion is applied to
the substrate surface by the coating method described above, the
coated surface is irradiated with UV light by the method described
above so as to obtain a coated product having a cured coating film
having excellent long-term outdoor weatherability, excellent wear
resistance, and high adhesion to plastic materials.
EXAMPLES
[0134] Next, the present invention is more specifically described
by using Examples and Comparative Examples. In the examples,
"parts" and "%" are on a weight basis unless otherwise noted.
Synthetic Example 1
Example of Preparing Polysiloxane
[0135] Into a reactor equipped with a stirrer, a thermometer, a
dropping funnel, a cooling tube, and a nitrogen gas inlet port, 415
parts of methyltrimethoxysilane (MTMS) and 756 parts of
3-methacryloyloxypropyltrimethoxysilane (MPTS) were charged, and
the resulting mixture was heated to 60.degree. C. under stirring
and a nitrogen gas stream. Thereto, a mixture of 0.1 parts of "A-3"
[iso-propyl acid phosphate produced by Sakai Chemical Industry Co.,
Ltd.] and 121 parts of deionized water was added dropwise for 5
minutes. After completion of the dropwise addition, the interior of
the reactor was heated to 80.degree. C. and stirring was conducted
for 4 hours to carry out a hydrolytic condensation reaction. As a
result, a reaction product was obtained.
[0136] Methanol and water contained in the reaction product were
removed under a reduced pressure of 1 to 30 kilopascal (kPa) under
a condition of 40 to 60.degree. C. As a result, 1000 parts of a
polysiloxane (a1) having a number-average molecular weight of 1000
and an active content of 75.0% was obtained.
[0137] Note that the "active content" is calculated by dividing the
theoretical yield (parts by weight) in the case where all of the
methoxy groups in the silane monomer used had undergone hydrolytic
condensation reactions by the actual yield (parts by weight) after
the hydrolytic condensation reaction, i.e., [theoretical yield
(parts by weight) in the case where all of the methoxy groups in
the silane monomer had undergone hydrolytic condensation
reactions/actual yield (parts by weight) after the hydrolytic
condensation reaction].
Synthetic Example 2
Example of Preparing Compound Resin (A-1)
[0138] Into a reactor the same as that in Synthetic Example 1, 20.1
parts of phenyltrimethoxysilane (PTMS), 24.4 parts of
dimethyldimethoxysilane (DMDMS), and 107.7 parts of n-butyl acetate
were charged and the resulting mixture was heated to 80.degree. C.
under stirring and a nitrogen gas stream. A mixture of 15 parts of
methyl methacrylate (MMA), 45 parts of n-butyl methacrylate (BMA),
39 parts of 2-ethylhexyl methacrylate (EHMA), 1.5 parts of acrylic
acid (AA), 4.5 parts of MPTS, 45 parts of 2-hydroxyethyl
methacrylate (HEMA), 15 parts of n-butyl acetate, and 15 parts of
tert-butylperoxy-2-ethylhexanoate (TBPEH) was added dropwise to the
reactor for 4 hours at the same temperature under stirring and a
nitrogen gas stream. After further conducting stirring for 2 hours
at the same temperature, a mixture of 0.05 parts of "A-3" and 12.8
parts of deionized water was added to the reactor dropwise for 5
minutes and stirring was conducted for 4 hours at the same
temperature to allow a hydrolytic condensation reaction to proceed
among PTMS, DMDMS, and MPTS. The reaction product was analyzed by
.sup.1H-NMR and it was found that nearly 100% of the
trimethoxysilyl groups of the silane monomer in the reactor had
hydrolyzed. Next, stirring was conducted for 10 hours at the same
temperature. As a result, a reaction product having a TBPEH
remaining amount of 0.1% or less was obtained. The amount of the
remaining TBPEH was measured by iodometry.
[0139] To the reaction product, 162.5 parts of polysiloxane (a1)
obtained in Synthetic Example 1 was added, the mixture was stirred
for 5 minutes, 27.5 parts of deionized water was added thereto, and
stirring was conducted for 4 hours at 80.degree. C. to allow a
hydrolytic condensation reaction to proceed between the reaction
product and the polysiloxane. The resulting reaction product was
distilled at a reduced pressure of 10 to 300 kPa under a condition
of 40 to 60.degree. C. to remove methanol and water generated, and
then 150 parts of methyl ethyl ketone (hereinafter referred to as
MEK) and 27.3 parts of n-butyl acetate were added thereto. As a
result, 600 parts (solid content: 50.0%) of a compound resin (A-1)
solution constituted by a polysiloxane segment and a vinyl polymer
segment in which the polysiloxane segment (a1) content was 50 wt %
was obtained.
Synthetic Example 3
Example of Preparing Compound Resin (A-2)
[0140] Into a reactor the same as that in Synthetic Example 1, 20.1
parts of PTMS, 24.4 parts of DMDMS, and 107.7 parts of n-butyl
acetate were charged and the resulting mixture was heated to
80.degree. C. under stirring and a nitrogen gas stream. Then a
mixture containing 15 parts of MMA, 45 parts of BMA, 39 parts of
EHMA, 1.5 parts of AA, 4.5 parts of MPTS, 45 parts of HEMA, 15
parts of n-butyl acetate, and 15 parts of TBPEH was added to the
reactor dropwise for 4 hours at the same temperature under stirring
and nitrogen gas stream. After further conducting stirring for 2
hours at the same temperature, a mixture of 0.05 parts of "A-3" and
12.8 parts of deionized water was added thereto dropwise for 5
minutes and stirring was conducted for 4 hours at the same
temperature to allow a hydrolytic condensation reaction to proceed
among PTMS, DMDMS, and MPTS. The reaction product was analyzed by
.sup.1H-NMR and it was found that nearly 100% of the
trimethoxysilyl groups of the silane monomer in the reactor had
hydrolyzed. Next, stirring was conducted for 10 hours at the same
temperature. As a result, a reaction product having a TBPEH
remaining amount of 0.1% or less was obtained. The amount of the
remaining TBPEH was measured by iodometry.
[0141] To the reaction product, 562.5 parts of the polysiloxane
(a1) obtained in Synthetic Example 1 was added, stirring was
conducted for 5 minutes, 80.0 parts of deionized water was added
thereto, and stirring was conducted for 4 hours at 80.degree. C. to
allow a hydrolytic condensation reaction to proceed between the
reaction product and the polysiloxane. The resulting reaction
product was distilled for 2 hours at a reduced pressure of 10 to
300 kPa under a condition of 40 to 60.degree. C. to remove methanol
and water generated, and then 128.6 parts of MEK and 5.8 parts of
n-butyl acetate were added. As a result, 857 parts of a compound
resin (A-2) having a polysiloxane segment (a1) content of 75 wt %
and a nonvolatile content of 70.0% and being constituted by a
polysiloxane segment and a vinyl polymer segment was obtained.
Synthetic Example 4
Example of Preparing Compound Resin (A-3)
[0142] Into a reactor the same as that in Synthetic Example 1, 17.6
parts of PTMS, 21.3 parts of DMDMS, and 129.0 parts of n-butyl
acetate were charged and the resulting mixture was heated to
80.degree. C. under stirring and a nitrogen gas stream. To the
reactor, a mixture of 21 parts of MMA, 63 parts of BMA, 54.6 parts
of EHMA, 2.1 parts of AA, 6.3 parts of MPTS, 63 parts of HEMA, 21
parts of n-butyl acetate, and 21 parts of TBPEH was added dropwise
for 4 hours at the same temperature under stirring and a nitrogen
gas stream. After further conducting stirring for 2 hours at the
same temperature, a mixture of 0.04 parts of "A-3" and 11.2 parts
of deionized water was added to the reactor dropwise for 5 minutes
and stirring was conducted for 4 hours at the same temperature to
allow a hydrolytic condensation reaction to proceed among PTMS,
DMDMS, and MPTS. The reaction product was analyzed by .sup.1H-NMR
and it was found that nearly 100% of the trimethoxysilyl groups of
the silane monomer in the reactor had hydrolyzed. Next, stirring
was conducted for 10 hours at the same temperature. As a result, a
reaction product having a TBPEH remaining amount of 0.1% or less
was obtained. The amount of the remaining TBPEH was measured by
iodometry.
[0143] To the reaction product, 87.3 parts of the polysiloxane (a1)
obtained in Synthetic Example 1 was added, the mixture was stirred
for 5 minutes, 12.6 parts of deionized water was added thereto, and
stirring was conducted for 4 hours at 80.degree. C. to allow a
hydrolytic condensation reaction to proceed between the reaction
product and the polysiloxane. The resulting reaction product was
distilled for 2 hours at a reduced pressure of 10 to 300 kPa under
a condition of 40 to 60.degree. C. to remove methanol and water
generated, and then 150 parts of MEK was added thereto. As a
result, 600 parts of a compound resin (A-3) having a polysiloxane
segment (a1) content of 30 wt % and a nonvolatile content of 50.0%
and being constituted by a polysiloxane segment and a vinyl polymer
segment was obtained.
Example 1
Inorganic Fine Particle Dispersion--Preparation of Dispersion
Liquid 1
[0144] The compound resin (A-1) solution (100 parts) (50 parts on a
solid basis) prepared in Synthetic Example 2, 50 parts of silica
fine particles (AEROSIL 50 produced by Aerosil Japan, average
primary particle size: about 30 nm), and 350 parts of methyl
isobutyl ketone (hereinafter referred to as MIBK) were blended.
[0145] The silica fine particles in the mixture were dispersed with
Ultra Apex Mill UAM 015 produced by Kotobuki Industries Co., Ltd.
In preparing the dispersion, zirconia beads having a diameter of 30
.mu.m were charged as the media in the mill so that the volume of
the zirconia beads was 50% of the volume of the mill.
Closed-circuit crushing was conducted on the mixture at a flow rate
of 1.5 L per minute. The closed-circuit crushing was conducted for
30 minutes. As a result, a dispersion liquid in which silica fine
particles were dispersed in the mixture of the compound resin (A-1)
and the dispersion medium was obtained. The obtained dispersion
liquid was discharged from the outlet of Ultra Apex Mill UAM 015,
the concentration of the dispersion medium was adjusted by using an
evaporator, and a dispersion liquid 1 (solid content: 50%) of the
silica fine particles was obtained.
[0146] The silica dispersion liquid 1 was stored at room
temperature (25.degree. C.) for 2 months. Precipitates were not
generated, the viscosity did not increase, and the storage
stability was high.
Examples 2 to 4
Inorganic Fine Particle Dispersion Liquid--Preparation of
Dispersion Liquids 2 to 4
[0147] Dispersion liquids 2 to 4 having a solid content of 50% were
obtained as in preparation of dispersion liquid 1 based on the
blend examples shown in Table 1.
[0148] The silica dispersion liquids 2 to 4 were stored at room
temperature (25.degree. C.) for 2 months. Precipitates were not
generated, the viscosity did not increase, and the storage
stability was high.
Example 5
Inorganic Fine Particle Dispersion Liquid--Preparation of
Dispersion Liquid 5
[0149] The compound resin (A) (100 parts) (50 parts on a solid
basis), 100 parts of titanium oxide fine particles (P-25 produced
by Aerosil Japan, anatase/rutile mixed crystal titanium oxide,
average primary particle size: about 12 nm) and 550 parts of
isopropyl alcohol (hereinafter referred to as IPA) were
blended.
[0150] The silica fine particles in the mixture were dispersed with
Ultra Apex Mill UAM 015 produced by Kotobuki Industries Co., Ltd.
In preparing the dispersion liquid, zirconia beads having a
diameter of 30 .mu.m were charged as the media in the mill so that
the volume of the zirconia beads was 50% of the volume of the mill.
Closed-circuit crushing was performed on the mixture at a flow rate
of 1.5 L per minute. The closed-circuit crushing was conducted for
30 minutes and a dispersion liquid in which the titanium oxide fine
particles were dispersed in the mixture of the compound resin (A-1)
and IPA was obtained. The obtained dispersion liquid was discharged
from the outlet of Ultra Apex Mill UAM 015, the dispersion medium
concentration was adjusted by using an evaporator, and a titanium
oxide dispersion liquid 5 having a solid content of 50% was
obtained as a result.
[0151] The titanium oxide dispersion liquid 5 was stored at room
temperature (25.degree. C.) for 2 months. Precipitates were not
generated, the viscosity did not increase, and the storage
stability was high.
Examples 6 and 7
Inorganic Fine Particle Dispersion Liquid--Preparation of
Dispersion Liquid 6 and Dispersion Liquid 7
[0152] Dispersion liquids 6 and 7 having a solid content of 50%
were obtained as in preparation of dispersion liquid 1 based on the
blend examples shown in Table 2.
[0153] The silica dispersion liquids 6 and 7 were stored at room
temperature (25.degree. C.) for 2 months. Precipitates were not
generated, the viscosity did not increase, and the storage
stability was high.
TABLE-US-00001 TABLE 1 Exam- Exam- Exam- ple 1 ple 2 ple 3 Disper-
Disper- Disper- Example 4 Example 5 sion sion sion Dispersion
Dispersion liquid 1 liquid 2 liquid 3 liquid 4 liquid 5 Compound
resin (A- 50 23 50 50 50 1) (solid basis) (MIBK) (350) (350) (350)
(350) (IPA) -- -- -- -- (550) Silica fine Aerosil 50 77 -- -- --
particles 50 Aerosil -- -- 50 -- -- 200 Aerosil -- -- -- 50 -- R711
Titanium P-25 -- -- -- -- 100 oxide fine particles Dispersibility
90 100 80 75 70 (average particle size, nm) Storage stability Good
Good Good Good Good (25.degree. C., 2 months)
TABLE-US-00002 TABLE 2 Example 6 Example 7 Dispersion Dispersion
liquid 6 liquid 7 Compound resin (A-2) (solid basis) 50 Compound
resin (A-3) (solid basis) 50 (MIBK) (350) (350) (IPA) -- -- Silica
fine Aerosil 50 50 50 particles Aerosil 200 -- -- Aerosil R711 --
-- Titanium oxide P-25 -- -- fine particles Dispersibility (average
particle size, nm) 80 100 Storage stability (25.degree. C., 2
months) Good Good
Legend in Tables 1 and 2
[0154] MIBK: methyl isobutyl ketone Aerosil 50: [silica fine
particles produced by Aerosil Japan, average primary particle size:
about 30 nm] Aerosil 200: [silica fine particles produced by
Aerosil Japan, average primary particle size: about 12 nm] Aerosil
R711: [methacryloyl-group-modified silica fine particles produced
by Aerosil Japan, average primary particle size: about 12 nm] P-25:
[titanium oxide fine particles produced by Aerosil Japan, average
primary particle size: about 12 nm]
Measurement of Dispersibility (Average Particle Size)
[0155] After the inorganic fine particle dispersion liquids were
prepared, the dispersibility was measured with a particle size
distribution analyzer employing a dynamic light scattering method
(ELS-Z produced by Otsuka Electronics Co., Ltd., cell width: 1 cm,
diluting solvent: MEK.
Example 8
Preparation of Paint 1
[0156] To 121.4 parts of the dispersion liquid 1, 24.3 parts of
pentaerythritol triacrylate (PETA) serving as a reactive compound,
15 parts of Burnock DN-902S [polyisocyanate produced by DIC
Corporation], 3.35 parts of Irgacure 184 [photopolymerization
initiator produced by Ciba Japan K.K.], 3.94 parts of Tinuvin 400
[hydroxyphenyl triazine-based UV absorber produced by Ciba Japan
K.K.], 1.0 parts of Tinuvin 123 [hindered amine-based light
stabilizer (HALS) produced by Ciba Japan K.K.], and 8.4 parts of
ethyl acetate were added to obtain an inorganic fine particle
dispersion 1 having a solid content of 60%. This inorganic fine
particle dispersion 1 was used as a paint 1. The paint 1 had good
fluidity.
Examples 9 to 12
Preparation of Paints 2 to 5
[0157] Inorganic fine particle dispersions 2 to 5 and paints 2 to 5
were obtained as in the preparation of the inorganic fine particle
dispersion 1 and the paint 1 based on the blend examples shown in
Table 3. The paints 2 to 5 exhibited good fluidity.
Example 13
Preparation of Paint 6
[0158] To 141.1 parts of the dispersion liquid 5, 14.3 parts of
pentaerythritol triacrylate (PETA) serving as a reactive compound,
3.35 parts of Irgacure 184 [photopolymerization initiator produced
by Ciba Japan K.K.], 3.94 parts of Tinuvin 400 [hydroxyphenyl
triazine-based UV absorber produced by Ciba Japan K.K.], and 1.0
parts of Tinuvin 123 [hindered amine-based light stabilizer (HALS)
produced by Ciba Japan K.K.] were added to obtain an inorganic fine
particle dispersion 6 having a solid content of 57%. The inorganic
fine particle dispersion 6 was used as a paint 6. The paint 6 had
good fluidity.
Comparative Example 1
Preparation of Comparative Paint, CP-1
[0159] To 90.6 parts of the compound resin (A-1) solution prepared
in Synthetic Example 2, 1.81 parts of Irgacure 184
[photopolymerization initiator produced by Ciba Japan K.K.], 2.19
parts of Tinuvin 400 [hydroxyphenyl triazine-based UV absorber
produced by Ciba Japan K.K.], 0.55 parts of Tinuvin 123 [hindered
amine-based light stabilizer (HALS) produced by Ciba Japan K.K.],
and 9.4 parts of Burnock DN-902S [polyisocyanate produced by DIC
Corporation] were added to obtain a comparative paint CP-1 (solid
content: 55%).
TABLE-US-00003 TABLE 3 Example Example Example Example Comparative
Example 8 Example 9 10 11 12 13 Example 1 Paint 1 Paint 2 Paint 3
Paint 4 Paint 5 Paint 6 CP-1 Dispersion 121.4 181.2 0 0 0 0 0
liquid 1 Dispersion 0 0 181.2 0 0 0 0 liquid 2 Dispersion 0 0 0
121.4 0 0 0 liquid 3 Dispersion 0 0 0 0 121.4 0 0 liquid 4
Dispersion 0 0 0 0 0 141.1 0 liquid 5 Compound 0 0 0 0 0 0 90.6
resin (A-1) solution PETA 24.3 0 0 24.3 24.3 14.3 0 I-184 3.35 3.35
3.35 3.35 3.35 3.35 1.81 Tinuvin 400 3.94 3.94 3.94 3.94 3.94 3.94
2.19 Tinuvin 123 1.00 1.00 1.00 1.00 1.00 1.00 0.55 Ethyl acetate
8.4 0 0 8.4 8.4 0 0 DN-902S 15 9.4 9.4 15 15 0 9.4 Silica fine 30
45.3 67.8 30 30 0 0 particle content (%) Titanium 0 0 0 0 0 47 0
oxide fine particle content (%)
Legend in Table 3
[0160] PETA: pentaerythritol triacrylate DN-902S: Burnock DN-901S
[polyisocyanate produced by DIC corporation] I-184: Irgacure 184
[photopolymerization initiator produced by Ciba Japan K.K.] Tinuvin
400: [hydroxyphenyl triazine-based UV absorber produced by Ciba
Japan K.K.] Tinuvin 123: [hindered amine-based light stabilizer
(HALS) produced by Ciba Japan K.K.]
Examples 14 to 19 and Comparative Example 2
Method for Forming a Cured Layer
[0161] Each of the paints 1 to 6 and the CP-1 prepared on the basis
of the blend examples shown in Table 3 was applied to a substrate
which was a PET film (haze: 0.5%) 210 mm.times.295 mm.times.0.125
mm in size so that the film thickness after drying was 10 .mu.m.
The applied paint was dried at 80.degree. C. for 4 minutes to form
a resin composition layer and then irradiated with a UV ray at
about 1000 mJ/cm2 dose using a mercury lamp having a lamp output of
1 kW. The resulting layer was left at 40.degree. C. for 3 days and
a cured layer was obtained as a result.
<Methods for Measuring Physical Properties>
[0162] [Surface Mechanical Properties. Crack Resistance (MW)]
[0163] An accelerated weathering test was conducted through a metal
weather test (MW) by using DMW produced by Daipla Wintes Co., Ltd.,
and unexposed specimens and specimens after 120 hours were compared
and evaluated by visual observation. Specimens which did not
undergo changes in surface conditions and the like were rated
"Good", specimens having cracks in some part were rated as "Fair",
and specimens having cracks in all parts of the surface were rated
"Poor". It should be noted that this evaluation method uses
conditions severer than those of the accelerated weathering test
that uses a sunshine weatherometer and is a test method for
substances that are intended for long-term outdoor use.
[Haze]
[0164] The degree of deterioration of a film having a cured layer
in the accelerated weathering test through metal weathering was
quantified into numbers in terms of haze. Typically, haze is
calculated from the following equation (unit is %) by measuring the
light transmittance of a test piece with a haze meter:
Th=Td/Tt [Math. 1]
(where Td represents diffuse light transmittance and Tt represents
total light transmittance)
[0165] The difference between the haze (%) of a film having a cured
layer after 120 hours and the haze (%) of an untested film having a
cured layer was indicated as the difference in haze AH (%). The
larger the difference, the severer the deterioration of the film
having a cured layer.
[Wear Resistance]
[0166] A surface of a film having a cured layer was rubbed in
accordance with JIS R3212 in a Taber's abrasion resistance test
(abrasive wheel: CS-10F, load: 500 g, number of rotations: 100).
The change in haze from the initial state, i.e., haze change
.DELTA.H (%) is measured. The smaller the difference, the higher
the wear resistance.
[Pencil Hardness]
[0167] A surface of a film having a cured layer was subjected to a
pencil scratch test under a 500 g load in accordance with JIS K
5400.
[Photocatalytic Activity Test (1): Measurement of Water Contact
Angle]
[0168] In accordance with a self-cleaning performance test set
forth in JIS R 1703-1 (2007), a test specimen without oleic acid
coating was irradiated with UV light and the limit contact angle of
the specimen before and after elapse of 3000 hours of sunshine
weatherometer testing was measured. The smaller the limit contact
angle, the higher the photocatalytic activity.
[Photocatalytic Activity Test (2): Decomposition of Wet Methylene
Blue]
[0169] The coefficient for decomposition of methylene blue was
calculated from a test specimen before and after 3000 hours of
sunshine weatherometer testing in accordance with JIS R 1703-2
(2007).
[0170] The larger the decomposition coefficient, the higher the
photocatalytic activity.
[0171] The results of evaluation of Examples 14 to 19 and
Comparative Example 2 are shown in Tables 4 and 5.
TABLE-US-00004 TABLE 4 Example Example Example Example Example
Example Comparative 14 15 16 17 18 19 Example 2 Name of paint Paint
1 Paint 2 Paint 3 Paint 4 Paint 5 Paint 6 Paint CP-1 Weathering
Crack Good Good Good Good Good Good Good test resistance Haze
(.DELTA.H) 0.8 0.7 1.0 0.9 0.6 1.0 0.8 Wear Wear 3.2 2.9 1.8 3.1
2.7 4.0 10.0 resistance resistance test (.DELTA.H) Surface Pencil
2H 2H 3H 2H 2H H F hardness hardness
TABLE-US-00005 TABLE 5 Comparative Example 18 Example 2 Name of
paint Paint 5 CP-1 Photo- Limit contact angle (.degree.) *3 5 87
catalytic Limit contact angle (.degree.) *4 8 70 activity
Decomposition 13 0 coefficient R *3 Decomposition 11 0 coefficient
R *4 *3 Value observed before sunshine weatherometer testing *4
Value observed after sunshine weatherometer testing
INDUSTRIAL APPLICABILITY
[0172] A inorganic fine particle dispersant according to the
present invention is capable of stably dispersing inorganic fine
particles such as silica fine particles or titanium oxide in a
reactive compound at a high concentration. The resulting inorganic
fine particle dispersion liquid has good storage stability and the
inorganic fine particle dispersion has good fluidity. A paint using
the dispersion is particularly useful as a paint for building
exterior required to achieve long-term weatherability and a paint
for a thermally deformable substrate such as plastic. A cured
product obtained by curing the paint has good long-term outdoor
weatherability and good wear resistance.
* * * * *