WO2012091178A1 - Additive for a coating agent and coating agent containing same - Google Patents

Abstract

This invention relates to an additive for coating agents, wherein the additive contains (A) a copolymer that contains the hydroxyl group and a group having a prescribed carbosiloxane dendrimer structure. Also, a coating agent that contains this additive for coating agents. Even at very small amounts of addition, the additive of the present invention impart an excellent uniformity, transparency, solvent resistance, staining/soiling resistance, and water repellency to a cured coating layer.

Description

DESCRIPTION

Title of Invention ADDI TI VE FOR A COATING AGENT AND COAT ING AGENT CONTAI NING SAME

Technical Field

[0001] Priority is claimed on Japanese Patent Application No. 2010-291 659, filed on December 28, 2010, the content of which is incorporated herein by reference.

[0002] The present invention relates to an additive for a coating agent (also referred to hereafter as a coating agent additive) wherein the additive exhibits an excellent compatibil ity with resins— and particularly with acryl ic resins that are cured by an isocyanate-based curing agent— and, even when added in a very small amount, imparts an excel lent uniformity, transparency, solvent resistance, staining/soiling resistance, and water repellency to the cured coating layer. The invention of the present application further relates to a coating agent that contains this coating agent additive.

Background Art

[0003] Silicone-modified vinyl resins comprising a vinyl polymer having a straight chain polyorganosiloxane group in side chain position are known. These resins are obtained by the copolymerization of a vinylic compound with a straight chain

polyorganosiloxane having a polymerizable group at one terminal (Patent Document 1 ). Due to the effect of the polyorganosiloxane group in side chain position, these silicone- modified vinyl resins exhibit an excellent staining/soiling resistance and water repellency and are incorporated in diverse coating agents in order to impart these functionalities. [0004] However, when a vinylic compound is polymerized in solution with a straight chain polyorganosiloxane having a polymerizable group at one terminal and the polyorganosiloxane used has a high molecular weight, the polymerizability of the straight chain organopolysiloxane having a polymerizable group at one terminal is diminished, which has caused the problem of impaired incorporation into the main chain structure, and problems have also arisen from a use standpoint and from the standpoint of property variability because the post-polymerization resin solution is cloudy and takes the form of a nonun iform resin solution. In addition, when a polyorganosiloxane is used that has a low molecular weight, the post-polymerization resin solution is transparent, but because organosiloxane exhibits a low compatibility with various materials, the problem has arisen of poor incorporation into cured systems, and a coating agent that uses such a silicone-modified vinyl resin provides, after application, a film with an unsatisfactory staining/soiling resistance and an unsatisfactory water repellency.

[0005] On the other hand, Patent Documents 2 to 6 examine the use of vinyl polymers containing a carbosiloxane dendrimer structure as additives in coating agents, but in these instances integration into a desired cured system cannot be achieved due to the absence of functional groups and the solvent resistance has been low as a result.

[Patent Document 1 ] JP 61 -078806 A

[Patent Document 2] JP 2000- 160025 A

[Patent Document 3] JP 2000- 198939 A

[Patent Document 4] JP 2001 - 192424 A

[Patent Document 5] JP 2000- 1 1 935 1 A

[Patent Document 6] JP 2002-256034 A

Disclosure of Invention

Technical Problems to be Solved [0006] An object of the present invention is to provide a coating agent additive that exhibits an excellent compatibility with various types of curable resin solutions and that provides the cured coating layer with an excellent uniformity, transparency, solvent resistance, staining/soi l ing resistance, and water repel lency. A further object of the present invention is to provide a coating agent.

Solution to Problems

[0007] The present inventors achieved the present invention as a result of intensive investigations in order to solve the problems identified above. The problems identified for the present invention are solved by a coating agent additive that contains a copolymer (A) that has in the molecule a hydroxyl group and a special carbosi loxane dendrimer structure and are solved by a coating agent that contains this additive. This copolymer (A) can be obtained by a copolymerization reaction among an unsaturated monomer containing a carbosi loxane dendrimer structure, a hydroxyl group-containing unsaturated monomer, and optionally an unsaturated monomer that does not contain the hydroxyl group.

[0008] This copolymer (A) molecule has a hydroxyl group, which is reactive with curable resins, and also has a carbosiloxane dendrimer structure that exhibits an excellent compatibility with curable resin solutions. Due to this, the use of this copolymer (A) as a coating agent additive not only makes possible the efficient introduction into a cured resin system, but even at very small amounts of addition can impart a satisfactory compatibility, solvent resistance, staining/soiling resistance, and water resistance, which originate with the carbosiloxane dendrimer structure, to the cured coating layer.

[0009] Thus, the aforementioned objects can be achieved by

" [ 1 ] An additive for a coating agent wherein the additive comprises (A) a copolymer that contains in the molecule a hydroxyl group and a group having a carbosiloxane dendrimer structure given by the fol lowing formula ( 1 )

[0010]

-(Z

wherein

Z is a divalent organic group,

p is 0 or 1 ,

1 2

R and R are each independently a C i _ i o alkyl group, an aryl group, or an aralkyi group, and

L ¹ is a silylalkyl group represented by the following structural formula (2) when i = 1

[0011]

wherein

Z and p are defined as above,

1 2

R and R are defined as above,

i is an integer from 1 to 10 that indicates the total number of generations of the silylalkyl group, and

L' ' is a group selected from the group consisting of the hydrogen atom, C J . J O alkyl groups, aryl groups, aralkyi groups, and the aforementioned silylalkyl group, wherein when i = c with c being an integer from 1 to 10 that indicates the generation of the silylalkyl group, is the hydrogen atom, a C j . i o alkyl group, an aryl group, or an aralkyl group, and when i < c, L^{i+ 1} is the aforementioned silylalkyl group, and a' is an integer from 0 to 3.

[2] The additive for a coating agent according to [ 1 ], wherein the copolymer (A) is a copolymer provided by the copolymerization of at least one or more selections from each of the following unsaturated monomers (al ) and (a2):

(al ) unsaturated monomers that have at least one hydroxyl group in the molecule and (a2) radically polymerizable unsaturated monomers given by the following formula ( )

[0012]

wherein

Y is a group that contains radically polymerizable unsaturation and

1 2 1 i

Z, p, R , R , L , and a are as defined above.

[3] The additive for a coating agent according to [2], wherein the group Y that contains radically polymerizable unsaturation in the radically polymerizable unsaturated monomer given by formula ( ) is a group selected from the group consisting of

acrylic group-containing organic groups and methacrylic group-containing organic groups given by the following general formulas

[0013] R⁴ O

CH₂— ""0 C """"""" O""— p5^„ wherein

4

R is the hydrogen atom or a methyl group and R⁵ is a Cj_io alkylene group

[0014]

wherein

4 5

R and R are defined as above,

alkenylaryl group-containing organic groups given by the following general formula

[0015]

wherein

R is the hydrogen atom or a methyl group,

7

R is a Cj.io alkyl group, R is a C 1 _ 10 alkylene group,

b is an integer from 0 to 4, and

c is 0 or 1 , and C2- 1 0 alkenyl groups.

[4] The additive for a coating agent according to [2] , wherein the copolymer (A) is a copolymer provided by the copolymerization additionally of at least one or more (a3) unsaturated monomer that does not contain the hydroxyl group in the molecule.

[5] The additive for a coating agent according to any one of [2] to [4], characterized in that the copolymer (A) is a copolymer provided by the copolymerization of the aforementioned unsaturated monomers (a l ) and (a2) and optional (a3) as constituent units thereof, wherein their mass ratios, taking the sum of the masses of the unsaturated monomers (a l ) to (a3) constituting the copolymer to be 100 mass parts, are in the range (a l ) : (a2) : (a3) = 0.5 - 50.0 : 0.5 - 50.0 : 0 - 99.0.

[6] The additive for a coating agent according to any one of [ 1 ] to [5], wherein the unsaturated monomer (a l ) constituting the copolymer (A) is at least one unsaturated monomer containing the hydroxyl group and selected from the group consisting of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, and hydroxypropyl methacrylate.

[7] A coating agent that contains the additive for a coating agent according to any one of [ l ] to [6] .

[8] A coating agent comprising the additive for a coating agent according to any one of [ 1 ] to [6], an acrylic resin wherein this acrylic resin does not contain a carbosiloxane dendrimer structure in its side chains, and a curing agent.

[9] The coating agent according to [8], wherein the acrylic resin contains at least two hydroxyl groups in each molecule.

[ 10] The coating agent according to [8], wherein the curing agent is an isocyanate group- containing compound .

[ 1 1 ] A coating agent comprising an additive for a coating agent according to any one of [ 1 ] to [6], an acrylic resin wherein this acryl ic resin does not contain a carbosiloxane dendrimer structure in its side chains, and a curing agent comprising an isocyanate group-containing compound, wherein the molar equivalent for the NCO group in the isocyanate compound, expressed per 1 equivalent of hydroxyl groups in the coating agent, is in the range from 0. 1 to 2.O." .

Advantageous Effects of Invention

[0016] The present invention provides a coating agent additive that exhibits an excellent compatibility with various types of curable resin solutions and that provides the cured coating layer with an excellent uniformity, transparency, solvent resistance, staining/soiling resistance, and water repellency. The present invention also provides a coating agent.

Description of the Invention

[0017] The coating agent additive of the present invention and the coating agent of the present invention are described in detail herebelow.

[0018] The coating agent additive according to the product of the present invention characteristically contains a copolymer (A) that contains in the molecule a hydroxyl group and a specific carbosiloxane dendrimer structure. This copolymer (A) is a copolymer obtained by the copolymerization of an unsaturated monomer having the hydroxyl group in the molecule and an unsaturated monomer having the carbosiloxane dendrimer structure in the molecule, and vinyl polymers are a favorable example of the copolymer (A). Here, a hydroxyl group-containing functional group and a group having a carbosiloxane dendrimer structure are introduced into side chain position on a chain- form molecular main chain composed of polymerized unsaturated units. The coating agent additive according to the present invention is preferably a vinyl copolymer having the carbosiloxane dendrimer structure and the hydroxyl group in side chain position on a main chain of polymerized vinyl units. [0019] A first characteristic feature of the copolymer (A) according to the product of the present invention is that it contains a group that has a carbosiloxane dendrimer structure. This carbosiloxane dendrimer structure denotes a high molecular weight group that is highly regularly branched in a radiating manner from a single core or nucleus. A highly branched siloxane · silalkylene copolymer is an example of a carbosiloxane dendrimer having such a structure; refer in this regard to JP 1 1 -001 530 A. The carbosiloxane dendrimer structure in the vinyl polymer in the present invention is a group given by the following formula ( 1 ).

formula ( 1 ):

[0020] Z in formula ( 1 ) is a divalent organic group, and the number of repeat units p thereof is 0 or 1 . The divalent organic group Z is not particularly limited, but can be exemplified by alkylene groups, arylene groups, aralkylene groups, ester-containing divalent organic groups, ether-containing divalent organic groups, ketone-containing divalent organic groups, and amide group-containing divalent organic groups. Organic groups preferred among the preceding are given by the following formulas.

0021 ]

[0022] R in the preceding formulas is a CJ.JO alkylene group, for example, methylene, ethylene, propylene, and butylene. Methylene and propylene are preferred among the preceding. R¹⁰ is a C\.\Q alkyl group, for example, methyl, ethyl, propyl, and butyl.

Methyl is preferred among the preceding. R¹¹ is a Cj.io alkylene group, for example, an alkylene group such as methylene, ethylene, propylene, and butylene. Ethylene is preferred among the preceding, d is an integer from 0 to 4, and e is 0 or 1.

1 2

[0023] R and R are independently a CJ.JO alkyl group, an aryl group, or an aralkyl group, for example, a C1.30 straight-chain or branched-chain alkyl group such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, and so forth; a C3.10 cyclic alkyl group such as cyclopentyl, cyclohexyl, and so forth; a Cg.jo aryl group such as phenyl, tolyl, xylyl, and so forth; a C7.10 aralkyl group such as benzyl; and groups provided by at least partially replacing the carbon-bonded hydrogen in the preceding groups with a halogen atom, e.g., fluorine, or with an organic group that contains, e.g., a carbinol group, epoxy group, glycidyl group, acyl group, carboxyl group, amino group, methacryl group, mercapto group, amide group, or oxyalkylene group. The alkyl group, aryl group, or aralkyl group is preferably an unsubstituted C 1 _ 10 alkyl group, aryl group, or aralkyl group; is more preferably an unsubstituted C j _6 alkyl group or aryl group; and particularly preferably is methyl, ethyl, or phenyl.

[0024] L is the silylalkyl group given by the following formula (2) when i = 1 .

[0025

2

Z and p in the formula are defined as above, and R and R are defined as above, i in the preceding formula is an integer from 1 to 10 that indicates the total number of

generations of the silylalkyl group, and is preferably from 1 to 5 from the perspective of synthesis and more preferably is from 1 to 3. On the other hand, i is preferably at least 2 from the standpoint of properties such as the hardness, solvent resistance,

staining/soiling resistance, water repeliency, and so forth of the cured layer provided by the cure of a curable composition according to the present invention, and second generation and third generation carbosiloxane dendrimer structures, in which i is 2 and 3, are included in the particularly favorable embodiments of the present invention.

[0026] L^{i+ 1} is a group selected from the group consisting of the hydrogen atom, C ] _ i o alkyl groups, aryl groups, aralkyl groups, and the aforementioned silylalkyl group, wherein when i = c— with c being an integer from 1 to 10 that indicates the generation of the silylalkyl group and is preferably 1 to 5, more preferably 1 to 3, and even more preferably 1 or 2— is the hydrogen atom, a C j . i o alkyl group, an aryl group, or an aralkyl group, and when i < c, L is the aforementioned silylalkyl group. integer from 0 to 3 and is preferably 0 to 2, more preferably 0 or 1 , and even more preferably 0.

[0027] The aforementioned carbosiloxane dendrimer structure is a chemical structure that is highly branched in a radiative configuration from a single silicon atom, and i, which indicates the total number of generations for this silylalkyl group, indicates the degree of branching. For example, when the total number of generations i is 1 and L' is, for example, the methyl group, the aforementioned carbosiloxane dendrimer structure denotes the following structure

[0028]

2

wherein Z, p, R , and R are defined as above and a is an integer from 0 to 3.

[0029] Similarly, when the generation i is 2 and is, for example, the methyl group, the aforementioned carbosiloxane dendrimer structure denotes the structure given below for p = 1 . The carbosiloxane dendrimer structure indicated by the following structure is called a "second generation type", and the copolymer (A) according to the present invention particularly preferably has a group that has this carbosiloxane dendrimer structure

[0030]

wherein Z, R , and R are defined as above and a and a are integers from 0 to 3.

[0031] When the generation i is 3 and is, for example, the methyl group, the aforementioned carbosi loxane dendrimer structure denotes the structure given below for p = 1 . The carbosiloxane dendrimer structure indicated by the following structure is called a "third generation type", and the copolymer (A) according to the present invention particularly preferably has a group that has this carbosiloxane dendrimer structure

[0032]

wherein Z, R , and R are defined as above and a , a , and a are integers from 0 to 3.

[0033] The following are preferred for the aforementioned carbosiloxane dendrimer structure. The carbosi loxane dendrimer structure given by formula (2-5) is particularly preferred from the standpoint of the properties of the coating layer, e.g., the hardness, solvent resistance, staining/soiling resistance, water repellency, and so forth.

[0034]

wherein Z and R are defined as above

[0035]

( 2 - 5 ) wherein Z and R are defined as above

[0036] Since the carbosiloxane unit broadens out into a dendrimer shape, a group having the carbosi loxane dendrimer structure described above is a functional group that, in comparison to a chain-form polysi loxane unit or a simple branched polysiloxane unit, exhibits a better compatibility with curable resins, can impart a higher water repellency (water resistance) to a coating layer, and can prevent the surface of the coating film from becoming extremely smooth. In addition, a group having the previously described carbosi loxane dendrim er structure is chemically stable and as a consequence can be used in combination with a wide range of coating agents.

[0037] A group having the carbosiloxane dendrimer structure described above can be introduced into the copolymer by the copolymerization with the other unsaturated monomer of (a2) a radically copolymerizable unsaturated monomer given by the following formula ( ) [0038]

2 wherein Y is a group containing radical ly polymerizable unsaturation and Z, p, R , R , L ¹ , and a' are defined as above.

[0039] The unsaturation-containing group has a radically polymerizable unsaturated bond but is not otherwise particularly limited, and can be exemplified by the vinyl grou allyl group, (meth)acryl group, and so forth.

[0040] Y in formula ( ) preferably has a group selected from the group consisting of acryl ic group-containing organic groups and methacrylic group-containing organic groups given by the fol lowing general formulas

[0041]

wherein

R is the hydrogen atom or a methyl group and

R i s a C i _ i o alkylene group

[0042]

wherein and R are defined as above,

alkenylaryl group-containing organic groups given by the following general formula

[0043]

wherein

R⁶ is the hydrogen atom or a methyl group,

7

R is a Ci_io alkyl group, R is a Ci_io alkylene group,

b is an integer from 0 to 4, and

c is 0 or 1 , and

C2-10 alkenyl groups.

[0044] This component (a2) can be exemplified by the following formulas.

[0046]

CH₃ CH_g

CH₂-CH-Si[OSi~C₂H₄-Si-(OSi-~H)₃}₃

I I

,CH₃ CH₃ [0047] These carbosiioxane dendrimer structure-containing unsaturated monomers can be produced, for example, according to the method for producing branched siloxane · silalkylene copolymers described in JP 1 1 -001 530 A (Japanese Patent Application 09- 1 71 1 54).

[0048] A second characteristic feature of the copolymer (A) according to the product of the present invention is that it has, in addition to the carbosiioxane dendrimer structure, the hydroxyl group in its molecu le. The hydroxyl group (-OH) is a component that is reactive with resins and particularly with acryl ic resins that are cured by an isocyanate- type curing agent, and, when the curable resin undergoes curing mainly by a

condensation reaction, the copolymer (A) is then efficiently incorporated into the cured resin system. As a result, the copolymer (A) according to the product of the present invention exhibits an improved affinity for curable resins, and the compatibility during curing and the transparency (uniformity) of the coating layer are improved.

[0049] Th is hydroxyl group (-OH) may be directly bonded to the main chain of the copolymer (A) or may be bonded to the main chain of the copolymer (A) across a divalent organic group (Z) as -Z-OH. This Z can be exemplified by the same divalent organic groups as already described above.

[0050] This hydroxyl group is introduced into the copolymer by the copolymerization with the other unsaturated monomer of (a l ) an unsaturated monomer that contains at least one hydroxyl group in the molecule. This component (a l ) can be exemplified by vinyl monomers that have the hydroxyl group in the molecule, for example, acrylate esters that have the hydroxyl group in the molecule, methacrylate esters that have the hydroxyl group in the molecule, allyl compounds that have the hydroxyl group in the molecule, vinyl ether compounds that have the hydroxyl group in the molecule, unsaturated carboxamide compounds that have the hydroxyl group in the molecule, unsaturated fatty acids that have the hydroxyl group in the molecule, unsaturated fatty acid esters that have the hydroxyl group in the molecule, and monomers obtained by addition reacting various hydroxyl group-containing monomers with an ε-caprolactone adduct. A single one of the preceding may be used or two or more may be used in combination.

[0051] Component (a l ) can be specifical ly exemplified by the following:

(meth)acrylate esters such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl

(meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4- hydroxybutyl (meth)acrylate, methyl 2-(hydroxymethyl)acrylate, ethyl 2- (hydroxymethyl)acrylate, butyl 2-(hydroxymethyl)acrylate, (4- hydroxymethylcyclohexyl)methyl (meth)acrylate, glycerol mono(meth)acrylate, 2- (meth)acryloyloxyethyl 2-hydroxypropyl phthalate, 2-hydroxy-3-phenoxypropyl

(meth)acrylate, and so forth; allyl compounds such as allyl alcohol, 2-hydroxyethyl allyl ether, and so forth; vinyl ether compounds such as 2-hydroxyethyl vinyl ether, 4- hydroxybutyl vinyl ether, 6-hydroxyhexyl vinyl ether, and so forth; unsaturated carboxamide compounds such as N-methylol(meth)acrylamide, N-methylolcrotonamide, and so forth; hydroxyl group-containing unsaturated fatty acids such as ricinoleic acid and so forth; hydroxyl group-containing unsaturated fatty acid esters such as alkyl ricinoleate and so forth; and monomers obtained by addition reacting these hydroxyl group-containing monomers with an ε-caprolactone adduct.

[0052] Particularly favorable examples of component (a l ) are acrylate esters and methacrylate esters, in each case having a hydroxyalkyl group in the molecule, and these can be more specifically exemplified by hydroxyl group-containing vinyl monomers such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, and 2-hydroxypropyl methacrylate.

[0053] The copolymer (A) according to the product of the present invention contains the hydroxyl group and the previously described carbosiloxane dendrimer structure in its molecule and is obtained by the copolymerizati on of the previously described components (a l ) and (a2), but may also optionally be a copolymer obtained using (a3) an unsaturated monomer that does not contain the hydroxyl group in the molecule. In particular, the component (a3) unsaturated monomer favorably forms a portion of the main chain of the copolymer (A) and is advantageously used as desired as a means for introducing different types of functional groups into the copolymer (A) according to the product of the present invention. In addition, the co-use of these monomers makes it possible to obtain the copolymer in an economically advantageous manner while imparting desired properties, such as blocking resistance or a leveling property, to the coating layer. It may also be possible to obtain additional improvements in properties such as the solubil ity through the selection of a unsaturated monomer.

[0054] The component (a3) unsaturated monomer can be favorably exempl ified by vinyl monomers that do not have a hydroxyl group. Specific examples are as follows: lower alkyl acrylates and lower alkyl methacrylates such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, and isopropyl methacrylate; glycidyl acrylate and glycidyl methacrylate; lower acrylates and methacrylates that have a C i _6 lower alkyl group, such as n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, tert- butyl acrylate, tert-butyl methacrylate, n-hexyl acrylate, n-hexyl methacrylate,

cyclohexyl acrylate, and cyclohexyl methacrylate; higher acrylates and methacrylates such as 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, octyl acrylate, octyl

methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, and stearyl

methacrylate; the vinyl esters of lower fatty acids, such as vinyl acetate and vinyl propionate; esters of h igher fatty acids, such as vinyl butyrate, vinyl caproate, vinyl 2- ethylhexanoate, vinyl laurate, and vinyl stearate; aromatic vinyl monomers such as styrene, vinyltoluene, benzyl acrylate, benzyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, and vinylpyrrolidone; amino group-containing vinyl monomers such as dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, and diethylaminoethyl methacrylate; amide group-containing vinyl monomers such as acrylamide, methacrylamide, N-methylolacrylamide, N- methylolmethacrylamide, N-methylolacrylamide, N-methoxymethylmethacrylamide, isobutoxymethoxyacrylamide, isobutoxymethoxymethacrylamide, N,N- dimethylacrylamide, and Ν,Ν-dimethylmethacrylamide; carboxylic acid-containing vinyl monomers such as acrylic acid, methacryl ic acid, itaconic acid, crotonic acid, fumaric acid, and maleic acid; ether bond-containing vinyl monomers such as tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, butoxyethyl acrylate, butoxyethyl methacrylate, cetyl vinyl ether, and 2-ethylhexyl vinyl ether; unsaturated group-containing silicone compounds such as a polydimethylsiloxane containing the acrylic group or methacryl ic group at one terminal and a polydimethylsiloxane containing an alkenylaryl group at one terminal ; butadiene; vinyl chloride; vinylidene chloride; acrylonitrile; methacrylonitrile; dibutyl fumarate; maleic anhydride; dodecylsuccinic anhydride; acryl glycidyl ether; methacryl glycidyl ether; 3 ,4-epoxycyclohexylmethyl acrylate; 3 ,4- epoxycyclohexylmethyl methacrylate; the alkali metal salts, ammonium salts, and organic amine salts of radically polymerizable unsaturated carboxyl ic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, fumaric acid, and maleic acid; radically polymerizable unsaturated monomers that have the sulfonic acid group, such as styrenesulfonic acid, as well as their alkali metal salts, ammonium salts, and organic amine salts; quaternary ammonium salts derived from acrylic acid or methacrylic acid, such as 3-methacryloxypropyltrimethylammonium chloride; and the methacryl ic acid esters of alcohols that have a tertiary amine group, such as a diethylamine ester of methacrylic acid, as well as their quaternary ammonium salts. Lower acrylates and methacrylates that have a C i _6 lower alkyl group are preferred. [0055] Component (a3) may also be an unsaturated monomer that has a silicon-bonded alkoxy group, and specific examples in this regard are

methacryloxypropyltriethoxysilane, acryloxypropyltriethoxysilane,

methacryloxypropyltrimethoxysilane, acryloxypropyltrimethoxysilane,

vinyltriethoxysi lane, vinyltrimethoxysilane, and vinyltris(2-methoxyethoxy)si lane.

[0056] Multifunctional vinyl monomers may also be used as component (a3), for example, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1 ,4-butanediol diacrylate, 1 ,4- butanediol dimethacrylate, 1 ,6-hexanediol diacrylate, 1 ,6-hexanediol dimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trioxyethylacrylate, trimethylolpropane trioxyethylmethacrylate, and unsaturated group- containing silicone compounds such as a polydimethylsiloxane endblocked by an alkenylaryl group at both molecular chain terminals.

[0057] A vinyl monomer containing a fluorinated organic group may also be used as component (a3). This vinyl monomer containing a fluorinated organic group is preferably given by the general formula CH2=CR ^{1 5}COOR^f, wherein R ^{1 5} is the hydrogen

f

atom or a methyl group and R is a fluorinated organic group and can be exemplified by the fluoroalkyl groups described above and fluoroalkyioxyfluoroalkylene groups. The compounds given by the following formulas, in which z is an integer from 1 to 4, are specific examples of this component (a3): CH2=CCH₃COO-CF₃ , CH₂=CCH₃COO-C2F₅, CH₂=CCH₃COO-nC₃F₇, CH₂=CCH₃COO-CF(CF₃)₂, CH2=CCH₃COO-nC₄F₉, CH₂=CCH₃COO-CF₂CF(CF₃)₂, CH₂=CCH₃COO-nC₅F _{1 1 ;} CH₂=CCH₃COO-nC₆F _{1 3}, CH₂=CCH₃COO-nC₈F i ₇, CH₂=CCH₃COO-CH₂CF₃ , CH₂=CCH₃COO-CH(CF₃)₂, CH₂=CCH₃COO-CH₂CH(CF₃)2, CH₂=CCH₃COO-CH₂(CF₂)2F, CH₂=CCH₃COO- CH₂(CF₂)₃F, CH₂=CCH₃COO-CH2(CF2)4F, CH₂= CH₃COO-CH₂(CF₂)₆F,

CH2=CCH₃COO-CH2(CF₂)8F, CH₂=CCH₃COO-CH₂CH₂CF₃, CH₂=CCH₃COO- CH₂CH2(CF₂)₂F, CH2=CCH₃COO-CH₂CH2(CF₂)₃F, CH₂=CCH₃COO- CH₂CH₂(CF₂)4F, CH2=CCH₃COO-CH₂CH2(CF2)6F, CH₂=CCH₃COO- CH₂CH₂(CF₂)₈F, CH₂=CCH₃COO-CH₂CH₂(CF2) i oF, CH₂=CCH₃COO- CH₂CH₂(CF₂) i 2F, CH₂=CCH₃COO-CH2CH2(CF2) i 4F, CH₂=CCH₃COO- CH₂CH₂(CF₂) i 6F, CH₂=CCH₃COO-CH2CH2CH₂CF3 , CH₂=CCH₃COO- CH₂CH₂CH2(CF₂)2F, CH₂=CCH₃COO-CH₂CH₂CH₂(CF₂)₂H, CH₂=CCH₃COO- CH₂(CF₂)4H, CH₂=CCH₃COO-CH₂CH₂(CF₂)₃H, CH₂=CCH₃COO-CH₂CH₂CF(CF₃)- [OCF₂CF(CF₃)]_z-OC₃F₇, CH₂=CCH₃COO-CH₂CH2CF2CF2-[OCF₂CF(CF3)]_z-

OC₃F₇CH₂=CHCOO-CF₃, CH₂=CHCOO-C₂F₅, CH₂=CHCOO-nC₃F₇, CH₂=CHCOO- CF(CF₃)₂, CH₂=CHCOO-nC₄F₉, CH₂=CHCOO-CF₂CF(CF₃)₂, CH₂=CHCOO-nC₅F _n , CH₂=CHCOO-nC₆F i ₃, CH₂=CHCOO-nC₈F _{1 7}, CH₂=CHCOO-CH₂CF₃, CH₂=CHCOO- CH(CF₃)₂, CH₂=CHCOO-CH₂CH(CF₃)₂, CH₂=CHCOO-CH₂(CF₂)2F, CH₂=CHCOO- CH₂(CF₂)₃F, CH₂=CHCOO-CH₂(CF₂)₄F, CH₂=CHCOO-CH₂(CF₂)6F, CH₂=CHCOO- CH₂(CF₂)8F, CH₂=CHCOO-CH₂CH₂CF₃, CH2=CHCOO-CH₂CH2(CF₂)2F,

CH2=CHCOO-CH₂CH₂(CF2)₃F, CH2=CHCOO-CH₂CH₂(CF2)4F, CH₂=CHCOO- CH₂CH₂(CF₂)₆F, CH₂=CHCOO-CH₂CH₂(CF₂)8F, CH₂=CHCOO-CH₂CH2(CF2) i oF, CH2=CHCOO-CH₂CH₂(CF₂) _{1 2}F, CH2=CHCOO-CH₂CH2(CF₂)i4F, CH₂=CHCOO- CH₂CH₂(CF₂) i 6F, CH2=CHCOO-CH₂CH₂CH2CF₃, CH₂=CHCOO- CH₂CH₂CH2(CF2)2F, CH₂=CHCOO-CH2CH₂CH₂(CF2)₂H, CH₂=CHCOO- CH₂(CF₂)₄H, CH2=CHCOO-CH₂CH₂(CF2)3H, CH2=CHCOO-CH₂CH₂CF(CF3)- [OCF₂CF(CF3)]_z-OC₃F7, and CH₂=CHCOO-CH2CH2CF₂CF2-[OCF2CF(CF₃)]_z- OC3F7.

[0058] Vinyl monomers given by the fol lowing formulas are preferred among the preceding: CH₂=CHCOO-CH₂CH2(CF₂)6F, CH₂=CHCOO-CH₂CH2(CF2)8F,

CH2=CCH₃COO-CH₂CH2(CF2)6F, CH2=CCH₃COO-CH2CH₂(CF2)8F, CH₂=CHCOO-

CH₂CF₃ and CH2=CCH₃COO-CH₂CF3. Vinyl monomers given by the following formulas are particularly preferred : CH₂^CHCOO-CH₂CF₃ and CH₂=CCH₃COO- CH₂CF₃.

[0059] Copolymer (A) is a copolymer provided by the copolymerization of the previously described unsaturated monomers (a l ), (a2), and optional (a3). Any ratio can be used in this copolymerization; however, letting 1 00 mass parts be the mass of all the unsaturated monomers, i .e. , the sum of the masses of the unsaturated monomers (a l ) to (a3), the mass ratios for the individual components can be established as suitable in the range of (a l ) : (a2) : (a3) = 0. 1 to 99.9 : 0. 1 to 99.9 : 0 to 99.8, preferably in the range of (a l ) : (a2) : (a3) = 0.5 to 50.0 : 0.5 to 80.0 : 0 to 99.0, more preferably in the range of (a l ) : (a2) : (a3) = 3.0 to 30.0 : 2.0 to 70.0 : 0 to 95.0, and particularly preferably in the range of (al ) : (a2) : (a3) = 5.0 to 20.0 : 7.0 to 60.0 : 20 to 88.0. In addition, a copolymer (A) that satisfies the condition {mass of component (a2) } > { mass of component (a l )} is particularly preferred.

[0060] The copolymer (A) obtained using the previously described polymerization ratios, due to the introduction of the hydroxyl group and a group having the carbosiloxane dendrimer structure in prescribed ratios in the main chain, exhibits a particularly good solubility in curable resins; is transparent and free of cloudiness when its synthesis is carried out in a solvent; and i s useful in that the coating agent additive has a particularly good timewise stability and a particu larly good blending stabi lity in al l types of coating agents. In addition, even at very small amounts of addition, the copolymer (A) offers the advantage of being able to provide a cured coating layer with a better uniformity, transparency, solvent resistance, staining/soiling resistance, and water repellency than does a copolymer lacking the hydroxyl group and the carbosiloxane dendrimer structure.

[0061 ] Radical polymerization methods and ionic polymerization methods can be used for the copolymerization method, but radical polymerization methods are preferred therebetween and the use of solution polymerization methods is particularly favorable. This solution polymerization is carried out by reacting the previously described unsaturated monomers in a solvent for 3 to 20 hours at a temperature of 50 to 1 50°C in the presence of a radical initiator. The solvent used here can be exemplified by aliphatic hydrocarbons such as hexane, octane, decane, cyclohexane, and so forth; aromatic hydrocarbons such as benzene, toluene, xylene, and so forth; ethers such as diethyl ether, dibutyl ether, tetrahydrofuran, dioxane, and so forth; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, and so forth ; esters such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, and so forth; alcohols such as methanol, ethanol , isopropyl alcohol, butanol, and so forth; and organosiloxane oligomers such as octamethylcyclotetrasi loxane, decamethylcyclopentasiloxane, hexamethyldisiloxane, octamethyltrisiloxane, and so forth. The heretofore known compounds typically used in radical polymerization methods can be used as the radical initiator, and specific examples are azobis compounds such as 2,2'- azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitri le), 2,2'-azobis(2,4- dimethylvaleronitrile), dimethyl 2,2'-azobis(2-methylpropionate), and so forth, and organic peroxides such as benzoyl peroxide, lauroyl peroxide, tert-butylperoxy benzoate, tert-butylperoxy 2-ethylhexanoate, and so forth. A single radical initiator may be used by itself, or two or more may be used in combination. The amount of radical initiator used is preferably in the range from 0. 1 to 5 mass parts per 1 00 mass parts for the total of components (a l ) to (a3). A chain transfer agent may also be added to the polymerization. This chain transfer agent can be specifically exemplified by mercapto compounds such as 2-mercaptoethanol, butyl mercaptan, n-dodecyl mercaptan, 3- mercaptopropyltrimethoxysilane, a polydimethylsiloxane that has the mercaptopropyl group, and so forth, and by halides such as methylene chloride, chloroform, carbon tetrachloride, butyl bromide, 3-chloropropyltrimethoxysi lane, and so forth .

[0062] After the polymerization, purification can be carried out by a method in which the unreacted residual vinyl monomer is removed by treatment under reduced pressure with heating, or by a method in which a deodorization treatment is carried out by running a hydrogenation reaction in the presence of a hydrogenation catalyst in the presence or absence of a solvent and the light components are distilled off under reduced pressure while in contact with nitrogen gas. A purified product is particularly preferably used in the case of use in topical applications where low odor and compatibility with other cosmetic components are required. The solvents, reaction conditions, low pressure conditions, and so forth that are used in the purification of known organopolysiloxane copolymers can be used and selected without particular limitation in and for the hydrogenation reaction and stripping step under consideration.

[0063] Viewed from the perspective of the ease of blending as a starting material for a coating agent, the number-average molecular weight of the copolymer (A) used in the present invention is preferably from 3,000 to 2,000,000 and more preferably is from 5,000 to 800,000. Its state can be exemplified by liquid, gum, paste, bulk solid, and powder, and it is preferably a dispersion or solution provided by dilution with a solvent.

[0064] The coating agent additive according to the present invention can be

incorporated into a desired coating agent. The main component of the coating agent is composed of a curing agent and an organic resin that can be used in a paint or coating agent and that can be cured by heating or can be cured at room temperature, while a curing catalyst may be added as necessary. More specifical ly, the organic resin can be exemplified by organic resins that do not correspond to the copolymer (A) used in the present invention and that are selected from alkyd resins, acrylic resins, polyester resins, polyurethane resins, and their mixtures.

[0065] When blended into a coating agent that contains an acrylic resin, the coating agent additive according to the present invention provides a particularly substantial improvement in compatibility and a particularly substantial improvement in the uniformity, transparency, solvent resistance, staining/soiling resistance, and water repellency of the cured coating layer. The acryl ic resin that is the base of the coating agent is an acrylic resin that does not correspond to the copolymer (A) used in the present invention and that does not contain a carbosiloxane dendrimer structure in side chain position.

[0066] The coating agent according to the present invention favorably contains an acrylic resin, a curing agent, and the previously described coating agent additive containing the copolymer (A), and may also incorporate a curing catalyst on an optional basis. Two or more components may be used in combination for the copolymer (A), for the acrylic resin, and for the curing agent.

[0067] A favorable acrylic resin is obtained by the polymerization, among the unsaturated monomers described above, of primarily an acrylate ester or acrylate ester monomer and favorably contains at least two hydroxyl groups in each molecule. Such an acrylic resin can be obtained by the polymerization, among the unsaturated monomers described above, of an acrylate ester or acrylate ester monomer and an unsaturated monomer that has the hydroxyl group in the molecule, for example, an acrylate ester that has the hydroxyl group in the molecule or a methacrylate ester that has the hydroxyl group in the molecule. These hydroxyl-functional acrylic resins are known as "acryl ic polyol resins" and are commercially available as, for example, "Burnock" (trademark) and "Acrydic" (trademark) from Dainippon Ink and Chemicals, Incorporated. A single species of such an acrylic resin may be used by itself or two or more species may also be used in combination.

[0068] The curing agent can be exempl ified by isocyanate compounds and melamine compounds. The isocyanate compounds can be specifically exemplified by

polyisocyanate compounds, e.g., aliphatic types such as xylene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate and their polyhydric alcohol adducts, biuret types, and trimer types, and aromatic types such as tolylene diisocyanate and diphenylmethane diisocyanate, and can be further exemplified by blocked isocyanate compounds. Commercially available isocyanate compound products can be exempl ified by "Burnock" (trademark) from Dainippon Ink and Chemicals, Incorporated, "Sumidur" (trademark) from Sumitomo Bayer Urethane, Ltd., "Takenate" (trademark) from Takeda Chemical Industries, Ltd., "Coronate" (trademark) from Nippon Polyurethane Industry Co., Ltd., and "Duranate" (trademark) from Asahi Kasei Chemicals. A single species of isocyanate compound may be used by itself, or two or more species may also be used in combination.

[0069J The melamine compound can be specifical ly exempl ified by

dimethylolmelamine, trimethylolmelamine, tetramethylolmelamine,

pentamethylolmelamine, hexamethylolmelamine, isobutyl ether-type melamine, n-butyl ether-type melamine, and so forth. A single species of these melamine compounds can be used by itself or two or more species can be used in combination . The amount of use of the melamine compound is preferably from 1 to 30 mass parts per 100 mass parts of the resin component in the coating agent.

[0070] The coating agent of the present invention particularly preferably contains an isocyanate group-containing compound as the aforementioned curing agent. The reason for this is as follows : the copolymer (A), because it contains the hydroxyl group, exhibits an excellent reactivity with the isocyanate group and through its reaction with the curing agent is then efficiently incorporated into the cured coating agent system . The isocyanate compounds described above are favorable curing agents.

[0071] The amount of use of the curing agent in the coating agent of the present invention can be selected as desired. When the curing agent is an isocyanate group- containing compound, the molar equivalent for the isocyanate (-NCO) group in the isocyanate compound is preferably in the range from 0. 1 to 2.0 per 1 equivalent of the hydroxyl group (-OH) in the coating agent. Here, the hydroxyl group in the coating agent is primarily the sum of the hydroxyl groups present in the hydroxyl-functional acrylic resin and the hydroxyl groups present in copolymer (A), i.e., the coating agent additive according to the present invention. A range that provides from 0.5 to 1 .5 equivalents of isocyanate groups per 1 equivalent of hydroxyl groups in the coating agent, i .e., a -OH/-NCO equivalent ratio in the range from 1 .0/0.5 to 1 .0/ 1 .5 , is particularly preferred. The range of 1 /0.7 to 1 .2 for the equivalent ratio is more preferred . Within this range, the acryl ic resin-containing coating agent can undergo a stable cure without foaming or the generation of cure defects. When, on the other hand, the isocyanate group is used at less than 0. 1 mole per 1 mole hydroxyl group, the cured coating layer may not exhibit a satisfactory staining/soiling resistance, water repellency, and non-stickiness. The cured coating layer may have a poor workability when the isocyanate group is used at more than 2 moles per 1 mole hydroxyl group. The respective amounts of use can be calculated by the usual methods from the hydroxyl value of the copolymer (A), the hydroxyl value of the acrylic resin, and the isocyanate group content of the isocyanate compound.

[0072] A curing catalyst may be incorporated on an optional basis, and the curing catalyst can be exemplified by organometal compounds, amine compounds, and acidic compounds. The organometal compounds can be specifically exemplified by organotin compounds such as tin octylate, di-n-butyltin dioctate, di-n-butyltin dilaurate, di-n- octyltin bis(isooctyl thioglycolate), di-n-butyltin sulfide, and di-n-octyltin oxide;

organotitanium compounds such as tetraisopropoxytitanium, tetra-n-butoxytitanium, isopropyl triisostearoyltitanate, and isopropyl tris(dioctyl pyrophospate)titanate;

organoaluminum compounds such as aluminum isopropylate and aluminum

tris(acetylacetonate); as well as by zinc octylate and magnesium naphthenate. The amine compounds can be exemplified by triethylamine, ethylenediamine, diethylenetriamine, dimethylaminoethanol, and isophoronediamine. The acidic compounds can be

exemplified by para-toluenesulfonic acid, dodecylbenzenesulfonic acid, phthalic acid, phthalic anhydride, phosphoric acid, monoalkyl phosphates, dialkyl phosphates, and organic amine blocked compounds of the preceding. A single one or two or more of these curing catalysts may be used on an optional basis. The amount of use for the curing catalyst is preferably from 0.001 to 5 mass parts per 100 mass parts of the resin component of the coating agent.

[0073] Additives can be exemplified by dehydrating agents, pigments, dispersing agents, defoamants, thickeners, settling inhibitors, sagging inhibitors, leveling agents, matting agents, anti-scratching agents, ultraviolet absorbers, photostabilizers, oxidation inhibitors, antimicrobials, and so forth; one or more of these can be used.

[0074] The dehydrating agent can be exemplified by dimethoxymethane, 1 , 1 - dimethoxyethane, 1 , 1 -dimethoxypropane, 1 , 1 -dimethoxybutane, and 1 , 1 - dimethoxycyclohexane and by hydrolyzable esters such as ethyl orthoformate, methyl orthoacetate, ethyl orthoacetate, dimethyldimethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ- methacryloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ- aminopropyltriethoxysi lane, methyl silicate, ethyl si licate, and so forth. The moisture fraction in the system can be removed by the addition of this dehydrating agent, which can bring about even further improvement in the storage stabil ity. The amount of use of the dehydrating agent is preferably from 0. 1 to 50 mass parts per 100 mass parts of the resin component in the coating agent.

[0075] The quantity of use of the other additives is not particularly limited, and these additives can be added and used in the quantities of use known for the usual additives for curable resin coating agents in conformity with the particular application.

[0076] The usual coating methods known for curable resin coating agents can be selected without particular lim itation, in accordance with the shape of the substrate and the purpose of the coating, for the method of applying the coating agent of the present invention to a substrate. In specific terms, any of the following may be used: bar coating methods, roll coating methods, blade coating methods, gravure coating methods, bead coating methods, curtain flow coating methods, immersion coating methods, and spray coating methods. Coating can be carried out on only one side or on both sides of a substrate and can be carried out on a portion of a substrate or over the entire substrate.

[0077] After appl ication, curing can be performed at any temperature from ambient temperature to 300°C; however, drying is preferably performed for 5 seconds to 60 minutes by heating at a temperature of 60 to 250°C in order to promote solvent evaporation and accelerate the crosslinking reaction. Higher curing temperatures provide shorter curing times, and the curing time can be further shortened by the co-use of a curing catalyst. After the coating has been dried in order to accelerate the crossl inking reaction, the coating can also be aged or matured for 1 to 7 days at a temperature of 30 to 120°C.

[0078] The thickness of the coating film provided by application of the coating agent of the present invention can be selected without particular limitation in accordance with the shape of the substrate and the purpose of the coating, but is typically in the range from 0. 1 to 100 μπι and preferably is 0.5 to 50 μπι.

[0079] Materials that may be coated with the coating agent of the present invention can be exemplified by metals, inorganic materials, plastics, and composite materials. The metals can be exemplified by stainless steel, aluminum, tin plate, galvanized plate, mild steel sheet and plate, copper, brass, various types of plated steel sheet and plate, titanium, and so forth. The coating agent of the present invention can also be advantageously used on metal substrates that have been subjected to a surface treatment such as a conversion treatment or an alumite treatment. The inorganic material can be exemplified by glass, mortar, slate, concrete, roof tile, and so forth. The plastics can be exempl ified by moldings of, e.g., surface-treated polypropylene, polyethylene, acrylic, polycarbonate, polystyrene, polyethylene terephthalate, nylon, polyester, rubber, elastomers, and so forth and by products provided by processing the preceding into a film . The composite materials can be exemplified by fiber-reinforced thermosetting plastics (FRP), fiber- reinforced thermoplastic plastics (FRTP), laminates, sandwich materials provided by the press bonding of a metal with an organic material, and plastics bearing a vapor-deposited metal film.

[0080] The coating layer provided by the cure of the coating agent of the present invention exhibits an excellent uniformity, transparency, solvent resistance,

staining/soiling resistance, and water repellency and is therefore effective, for example, for blocking greasy contaminants, dust and dirt borne in the air, and the contaminants admixed in exhaust gas and rainwater; for blocking various types of il licit materials such as graffiti, posters, bills, and stickers; and for preventing snow accretion, icing, and the attachment of aquatic microorganisms. Specific applications can be exemplified by blocking greasy contaminants, such as around kitchen stoves, on the doors of storage cabinets, at exhaust fans, on lighting covers, and so forth; preventing the soi ling of exterior walls, such as concrete and tile; preventing staining due to exhaust gases, e.g., of roadway tunnels and freeway sound-deadening wal ls; preventing the attachment of graffiti, posters, bi l ls, and stickers to exterior wal ls, public phone booths, utility poles, public toilets, and so forth; preventing snow accretion and icing on roofs and power lines; and preventing the attachment of barnacles that attach to the hulls of ships and vessels.

Examples

[0081 ] The present invention is specifical ly described by the practical examples and comparative examples given below, but the present invention is not limited to the following examples. The viscosity is the value measured at 25 °C. The properties of the copolymer (A) were measured using the following methods.

[0082]

Method for measuring the viscosity of the copolymer

The kinematic viscosity of the copolymer was measured by a capi llary viscosity measurement procedure using a Ubbelohde vi scometer.

Method for measuring the molecular weight and dispersitv of the copolymer

The molecular weight and dispersity of the copolymer were measured by gel permeation chromatography (GPC). The molecular weight obtained for the copolymer is reported as the number-average molecular weight as polystyrene. Method for measuring the solids fraction concentration of the copolymer

1 g of the silicone-modified vinyl copolymer obtained in the particular example was weighed into an aluminum dish and then heated for 2 hours in a 150°C oven. The solids fraction concentration was calculated from the amount of solvent evaporation (g).

[0083] [Practical Example 1 ]

355 g of butyl acetate was introduced into a 1000-mL four-neck flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen introduction tube and was stirred and heated to 70°C under a nitrogen atmosphere.

The following were added dropwise to this butyl acetate over 2 hours:

(a-3 - 1 ) 102.5 g of methyl methacrylate,

(a-3-2) 22.5 g of n-butyl acrylate,

(a- 1 - 1 ) 25 g of 2-hydroxyethyl methacrylate,

(a-2- 1 ) 1 00 g of the carbosiloxane dendrimer structure-containing vinyl monomer with the following formula,

and 2.5 g of the radical polymerization initiator V-601 from Wako Pure Chemical Industries, Ltd.

After the completion of the dropwise addition, a reaction was run for 6 hours at 70°C to obtain a coating agent additive containing a sil icone-modified vinyl copolymer (A l ) with a number-average molecular weight as polystyrene of 8,200, a dispersity of

2

9.24, a kinematic viscosity of 108.26 mm /s, and a solids fraction concentration of 36.9%.

[0084] [Practical Example 2] A coating agent additive containing a silicone-modified vinyl copolymer (A2) with a number-average molecular weight as polystyrene of 25,300, a dispersity of 6.92, a

2

kinematic viscosity of 422.69 mm /s, and a solids fraction concentration of 40.4% was obtained proceeding as in Practical Example 1 , but using

(a-2-2) a carbosiloxane dendrimer structure-containing vinyl monomer with the following formula

in place of the component (a-2- 1 ) used in Practical Example 1 .

[0085] [Comparative Example 1 ]

A coating agent additive containing a silicone-modified vinyl copolymer (B l ) with a number-average molecular weight as polystyrene of 12,900, a dispersity of 9.04,

2

kinematic viscosity of 404.93 mm /s, and a solids fraction concentration of 39. 1 %) was obtained proceeding as in Practical Example 1 , but using a straight chain polysiloxane structure-containing vinyl monomer with the following formula

in place of the component (a-2- 1 ) used in Practical Example 1 .

[0086] [Comparative Example 2] A cloudy white coating agent additive containing a sil icone-modified vinyl copolymer (B2) with a number-average molecular weight as polystyrene of 2,700, a

2

dispersity of 9.94, a kinematic viscosity of 21 .67 mm /s, and a solids fraction concentration of 3 1 .7% was obtained proceeding as in Practical Example 1 , but using a straight chain polysiloxane structure-containing vinyl monomer with the following formula

in place of the component (a-2- 1 ) used in Practical Example 1 .

[0087] [Comparative Example 3]

A cloudy white coating agent additive containing a silicone-modified vinyl polymer (B3) with a number-average molecular weight as polystyrene of 6,900, a

2

dispersity of 7.63, a kinematic viscosity of 2052.79 mm /s, and a solids fraction concentration of 37.8% was obtained proceeding as in Practical Example 1 , but using a straight chain polysiloxane structure-containing vinyl monomer with the following formula

in place of the component (a-2- 1 ) used in Practical Example 1 .

[0088] Coating agents containing the sil icone-modified vinyl polymers obtained in Examples 1 and 2 and Comparative Examples 1 to 3 were evaluated as described below. In each experiment, the si licone-modified vinyl polymer was added in an amount that provided 1 mol% with reference to the total molar for the hydroxyl group (referred to below as the "total polyol") in the acryl ic polyol resin.

[0089]

Evaluation of the coating agents

A coating agent containing a silicone-modified vinyl copolymer and having an

NCO/OH molar ratio = 1 .5 was obtained by mixing the following by stirring: 16. 1 g, i .e., the amount that provided 1 mol% with reference to the total polyol, of the coating agent additive, which had an OH value of 43.2 and had been adjusted to a concentration of 3 wt% using butyl acetate; 78.3 g of the acryl ic polyol resin "Acryd ic (trademark) A-829" from Dainippon Ink and Chemicals, Incorporated, which had an OH value of 44 and a solids fraction concentration of 60 wt%; 25.0 g of the polyisocyanate compound

"Burnock (trademark) D-950" from Dainippon Ink and Chemicals, Incorporated, which had an NCO content of 12.5% and a solids fraction concentration of 75%; and 101 .3 g butyl acetate as a diluent solvent.

[0090] The coating agent was coated using a Mayer bar on an aluminum plate (JIS H 4000, 5 x 50 x 1 50 mm) and was cured by heating for 1 5 minutes at 1 50°C to yield a coated aluminum plate having a dry film thickness of 10 μπι for the coating layer, i .e., the coating film. The thusly obtained coated aluminum plate was used to evaluate various properties according to the following criteria. The results are given in Table 1 .

[0091]

Appearance

The appearance of the resulting coating film was visually inspected and was evaluated using the fol lowing criteria.

O : The coating film is transparent.

Δ : The coating film presents a very slight cloudiness or unevenness.

x : The coating film presents white cloudiness. Solvent resistance

A xylene-impregnated felt was installed in a rubbing tester from Taihei Rika Kogyo Kabushiki Kaisha; a 1 .2 kg load was applied; the surface of the coating film was subjected to 100 back-and-forth excursions; and the status of the coating film was then visually inspected and evaluated using the following criteria.

O : no change in the appearance of the surface

Δ : minor change in the appearance of the surface

x : the appearance of the surface is changed

Staining/soiling resistance

The cured coating film was marked with a Magic Ink blue ink pen from Pentel Co., Ltd., and was air-dried for 1 0 minutes and was then wiped with a KimWipe. The status of crawl ing by the Magic Ink when marking was performed and the status of the wiping- off effort were visually inspected and evaluated using the following criteria.

O : The Magic Ink underwent crawling and could be easily wiped off.

x : The Magic Ink did not undergo crawling and it was difficult to wipe off the text.

The contact an le with water

A water droplet was placed on the cured coating film and the contact angle with the water was measured using a DM-700 contact angle meter from Kyowa Interface Science Co., Ltd.

Pencil hardness

The measurement was performed using a method in accordance with the pencil scratch test of JI S K 5400-6- 1 4. Coefficient of friction

The measurement was carried out under the following conditions using a Heid Type 14 friction tester from Shinto Scientific Co., Ltd. : 100 x 1 5 mm SUS cylinder, g load, and 100 mm/minute pull rate.

[0092] [Table 1 .]

[0093] Even at very small amounts of addition, i .e., 1 mol% with reference to the total polyol, the conventional coating agent additive containing a strai ght chain polysiloxane results in a white cloudy appearance for the coating film and thus does not yield a uniform coating fi lm. The coating agent additive of the present invention, on the other hand, was characterized by an excellent compatibil ity with the curable resin component that was the base of the coating agent and thus characteristically yielded a uniform and transparent coating film . In addition, the use of the sil icone-modified vinyl copolymer (A l ), which had the second generation carbosiloxane dendrimer structure shown in Practical Example 1 , not only provided these same properties, but was observed to provide a coating agent that also exhibited excellent coating layer properties such as staining/soiling resistance, water repellency, and so forth.

[0094] [Industrial Applicability]

The coating agent additive of the present invention is a copolymer that has the hydroxyl group and a carbosiloxane dendrimer structure in side chain position and can provide a transparent resin solution. In addition, due to the effect of the carbosiloxane dendrimer structure, a coating agent that incorporates the coating agent additive of the present invention provides, even at very small amounts of addition, a cured coating layer, i.e., a cured coating film, that is endowed with solvent resistance, staining/soiling resistance, water repellency, and so forth. Due to th is, the coating agent of the present invention, through its application on any of a variety of articles, can function as a surface protectant and can impart staining/soiling resistance and thus can be used to counter a broad range of stains, dirt, and contaminants, such as oily or greasy contam inants and stains, the dust and dirt borne in the air, and the contaminants admixed in exhaust gas and rainwater. The coating agent additive according to the present invention is also useful as a component for incorporation in paints and coating agents in general and is also effective when it is desired to restrain the smoothness of silicones while conferring their other properties, such as water repellency, for example, in the painting of gymnasium floors.

Claims

An additive for a coating agent wherein the additive comprises

(A) a copolymer that contains in the molecule a hydroxyl group and a group having a carbosiloxane dendrimer structure given by the following formula ( 1 )

wherein

Z is a divalent organic group,

p is 0 or 1 ,

1 2

R and R are each independently a C \ . \ Q alkyl group, an aryl group, or an aralkyl group, and

L ¹ is a silylalkyl group represented by the following structural formula (2) when i

wherein

and p are defined as above,

R and R are defined as above, i is an integer from 1 to 10 that indicates the total number of generations of the silylalkyl group, and

L^{,+ 1} is a group selected from the group consisting of the hydrogen atom, C ] _ ] o alkyl groups, aryl groups, aralkyl groups, and the aforementioned silylalkyl group, wherein when i = c with c being an integer from 1 to 10 that indicates the generation of the silylalkyl group, is the hydrogen atom, a C \ . \ Q alkyl group, an aryl group, or an aralkyl group, and when i < c, is the aforementioned silylalkyl group, and a' is an integer from 0 to 3.

The additive for a coating agent according to claim 1 , wherein the copolymer (A) is a copolymer provided by the copolymerization of at least one or more selections from each of the following unsaturated monomers (a l ) and (a2) : (a l ) unsaturated monomers that have at least one hydroxyl group in the molecule and

(a2) radically polymerizable unsaturated monomers given by the following formula ( Γ)

wherein

Y is a group that contains radical ly polymerizable unsaturation and

1 2 1 l

Z, p, R , R , L , and a are as defined above. The additive for a coating agent according to claim 2, wherein the group Y that contains radically polymerizable unsaturation in the radically polymerizable unsaturated monomer given by formula ( ) is a group selected from the group consisting of

acryl ic group-containing organic groups and methacrylic group-contain ing organic groups given by the following general formulas

wherein

R is the hydrogen atom or a methyl group and R⁵ is a C i _ i o alkylene group

wherein

4 5

R and R are defined as above,

alkenylaryl group-containing organic groups given by the following general formula

wherein

R is the hydrogen atom or a methyl group,

R is a C j . i o alkyl group, R is a C i _ i o alkylene group,

b is an integer from 0 to 4, and

c is 0 or 1 , and

C2- 10 alkenyl groups.

The additive for a coating agent according to claim 2, wherein the copolymer (A) is a copolymer provided by the copolymerization additionally of at least one or more (a3) unsaturated monomer that does not contain the hydroxyl group in the molecule.

The additive for a coating agent according to any one of claims 2 to 4, characterized in that the copolymer (A) is a copolymer provided by the

copolymerization of the aforementioned unsaturated monomers (a l ) and (a2) and optional (a3) as constituent units thereof, wherein their mass ratios, taking the sum of the masses of the unsaturated monomers (a l ) to (a3) constituting the copolymer to be 100 mass parts, are in the range

(a l ) : (a2) : (a3) = 0.5 - 50.0 : 0.5 - 50.0 : 0 - 99.0.

The additive for a coating agent according to any one of claims 1 to 5, wherein the unsaturated monomer (a l ) constituting the copolymer (A) is at least one unsaturated monomer containing the hydroxyl group and selected from the group consisting of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, and hydroxypropyl methacrylate.

A coating agent that contains the additive for a coating agent according to any one of claims 1 to 6. A coating agent comprising the additive for a coating agent according to any one of claims 1 to 6, an acryl ic resin wherein this acrylic resin does not contain a carbosiloxane dendrimer structure in its side chains, and a curing agent.

The coating agent according to claim 8, wherein the acrylic resin contains at least two hydroxyl groups in each molecule.

The coating agent according to claim 8, wherein the curing agent is an isocyanate group-containing compound.

A coating agent comprising an additive for a coating agent according to an one of claims 1 to 6, an acryl ic resin wherein this acrylic resin does not contain a carbosiloxane dendrimer structure in its side chains, and a curing agent comprising an isocyanate group-containing compound, wherein the molar equivalent for the NCO group in the isocyanate compound, expressed per 1 equivalent of hydroxyl groups in the coating agent, is in the range from 0.1 to 2.0.