JPH093394A - Coating composition - Google Patents

Abstract

PURPOSE: To form a coating which is excellent in properties, such as transparency, gloss, apparent thickness, mechanical strength, acid resistance, and solvent resistance, and, when used outdoors for a long period of time, possesses long- term weatherability, such as gloss retention and fading resistance by incorporating a copolymer of a particular UV-absorbing monomer (A) with a particular cycloalkyl-contg. unsatd. monomer (B) and a hydroxyl-contg. monomer (C). CONSTITUTION: 0.1 to 30wt.% component (A) represented by the formula I (R<1> represent H or a 1-8C hydrocarbon radical; R<2> represents a 1-6C alkylene; R<3> represent H or methyl; and X represents H, a halogen, a 1-8C hydrocarbon radical, a 1-4C alkoxy, cyano, or nitro) is copolymerized with 5 to 98.9wt.% component (B) represented by the formula II (R<10> represents H or a 1-2C hydrocarbon radical; and Z represents an optionally substd. cycloalkyl) and 1 to 45wt.% component (C) (e.g. hydroxyethyl (meth)acrylate). The copolymn. temp. is pref. room temp. to 200 deg.C. Pref., the copolymer has a wt. average mol.wt. of 2,000 to 300,000.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention is excellent in transparency, gloss, durability, mechanical strength, acid resistance, solvent resistance and the like, and has gloss retention and discoloration resistance in long-term outdoor use. And a coating composition capable of forming a coating film having excellent long-term weather resistance.

[0002]

2. Description of the Related Art Heretofore, there has been known a coating composition comprising a hydroxyl group-containing polymerization composition and a crosslinking agent composed of a polyisocyanate compound capable of reacting with the hydroxyl group. This coating composition has good dryability, cures even at room temperature, and has excellent chemical properties such as acid resistance and solvent resistance. In addition, in particular, when an acrylic polyol is used as the polymerization composition containing a hydroxyl group, gloss,
It can form a coating film that has excellent aesthetics such as transparency and meat retention, and also has excellent chemical properties, and is often used outdoors as an automobile repair agent, building material, woodworking material, etc. .

Examples of such a coating composition include an unsaturated monomer containing a cycloalkyl group, an unsaturated monomer containing a hydroxyl group, an unsaturated monomer containing an acidic functional group, and A coating composition in which a polyisocyanate compound is mixed with a hydroxyl group-containing compound obtained by copolymerizing another unsaturated monomer has been reported (JP-A-5-28748).

However, the coating film formed from the above-mentioned conventional coating composition has a problem that it has poor weather resistance such as deterioration of gloss and transparency due to ultraviolet rays when used for a long period of time.

Therefore, in order to improve the above problems, a coating composition using a copolymer of an ultraviolet absorber or an ultraviolet stabilizer having a polymerizable skeleton and a hydroxyl group-containing monomer as a polymerization composition A composition has been used. As such a coating composition, for example, an ultraviolet stable monomer, an unsaturated monomer containing a cycloalkyl group, an unsaturated monomer containing a hydroxyl group, an ultraviolet absorbing monomer, and other In the hydroxyl group-containing compound obtained by copolymerizing the unsaturated monomer of
A coating composition containing a polyisocyanate compound has been reported (JP-A-6-207142).

[0006]

However, in the above-mentioned conventional coating composition, an acrylic acid ester of a benzophenone derivative is used as the ultraviolet absorbing monomer, and the ultraviolet absorbing copolymer obtained from this is used. Has a relatively short maximum absorption wavelength, and is therefore insufficient to absorb a long wavelength region (320 nm to 400 nm) in which the integrated energy is relatively large in the ultraviolet region of the sun's rays on the ground, A coating composition having sufficient long-term weather resistance cannot be obtained.

The present invention has been made in view of the above-mentioned conventional problems, and its objects are transparency, luster, durability and
It has excellent mechanical strength, acid resistance, solvent resistance, etc.
Provided is a coating composition capable of forming a coating film which is particularly excellent in ultraviolet absorption in the wavelength range of 300 nm to 400 nm and has excellent long-term weather resistance such as gloss retention and discoloration resistance in long-term outdoor use. Especially.

[0008]

Means for Solving the Problems The inventors of the present invention have made earnest studies on a coating composition in order to achieve the above object, and as a result, have found that the composition has an ultraviolet absorbing monomer having a specific structure and a specific structure. Cycloalkyl group-containing unsaturated monomer, a coating composition containing a copolymer obtained by copolymerizing a monomer composition containing a hydroxyl group-containing monomer, transparency, gloss, fleshiness, It has excellent mechanical strength, acid resistance, solvent resistance, etc., and also has excellent UV absorption ability in the wavelength range of 300 nm to 400 nm, and has long-term gloss retention and discoloration resistance for long-term outdoor use. The inventors have found that a coating film having excellent weather resistance can be formed, and completed the present invention.

That is, the coating composition of the invention according to claim 1 has the general formula (1) in order to solve the above problems.

[0010]

Embedded image

(Wherein R ¹ is a hydrogen atom or a group having 1 to 1 carbon atoms)
8 represents a hydrocarbon group, R ² represents a linear or branched alkylene group having 1 to 6 carbon atoms, R ³ represents a hydrogen atom or a methyl group, X represents a hydrogen atom or a halogen group. Represents a hydrocarbon group having 1 to 8 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group), and a general formula (2)

[0012]

[Chemical 6]

(In the formula, R ¹⁰ represents a hydrogen atom or a carbon number of 1 to
2 represents a hydrocarbon group, and Z represents a cycloalkyl group which may have a substituent), and a monomer containing a cycloalkyl group-containing unsaturated monomer and a hydroxyl group-containing monomer. It is characterized by including a copolymer obtained by copolymerizing a body composition.

In order to solve the above problems, the coating composition of the invention of claim 2 is the same as the coating composition of claim 1, wherein the monomer composition is represented by the general formula (3).

[0015]

[Chemical 7]

(Wherein R ⁶ represents a hydrogen atom or a cyano group, R ⁷ and R ⁸ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 2 carbon atoms, and R ⁹ represents a hydrogen atom or a carbon atom. Represents a hydrocarbon group of the number 1 to 18, Y represents an oxygen atom or an imino group) and / or a UV stable monomer represented by the general formula (4)

[0017]

Embedded image

(In the formula, R ⁶ represents a hydrogen atom or a cyano group, R ⁷ and R ⁸ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 2 carbon atoms, and Y represents an oxygen atom or an imino group. Which further comprises a UV-stable monomer.

In order to solve the above-mentioned problems, the coating composition of the invention according to claim 3 is the coating composition according to claim 1 or 2, wherein the copolymer has a hydroxyl group in one molecule. It is characterized in that a cross-linking agent having two or more reactive functional groups is blended.

In order to solve the above problems, the coating composition of the invention of claim 4 is the coating composition of claim 3, wherein the crosslinking agent is a polyisocyanate compound or a modified product thereof. It is characterized by that.

The present invention will be described in detail below. The copolymer according to the present invention comprises an ultraviolet absorbing monomer represented by the general formula (1), a cycloalkyl group-containing unsaturated monomer represented by the general formula (2), and a hydroxyl group-containing group. It is obtained by copolymerizing a monomer composition containing a monomer. The above-mentioned monomer composition, if necessary, contains the UV stable monomer represented by the general formula (3) and / or the UV stable monomer represented by the general formula (4). May be included. Furthermore,
It may contain a monomer other than the above monomers.

The ultraviolet absorbing monomer represented by the general formula (1) according to the present invention (hereinafter referred to as the ultraviolet absorbing monomer (1)) is a substituent represented by R ¹ in the formula. Is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and R ²
The substituent represented by is composed of a linear or branched alkylene group having 1 to 6 carbon atoms, the substituent represented by R ³ is composed of a hydrogen atom or a methyl group, and the substituent represented by X is substituted. A benzotriazole group whose group is a hydrogen atom, a halogen group, a hydrocarbon group having 1 to 8 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group.

Specific examples of the UV absorbing monomer (1) include 2- [2'-hydroxy-5 '-(methacryloyloxymethyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy-5 '-(methacryloyloxyethyl) phenyl] -2H-benzotriazole, 2-
[2'-Hydroxy-5 '-(methacryloyloxypropyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy-5'-(methacryloyloxyhexyl) phenyl] -2H-benzotriazole, 2- [2 '-Hydroxy-3'-
t-Butyl-5 '-(methacryloyloxyethyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy-5'-
t-Butyl-3 '-(methacryloyloxyethyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy-5'-
(Methacryloyloxyethyl) phenyl] -5-chloro
-2H-benzotriazole, 2- [2'-hydroxy-5 '-(methacryloyloxyethyl) phenyl] -5-methoxy-2
H-benzotriazole, 2- [2'-hydroxy-5 '-(methacryloyloxyethyl) phenyl] -5-cyano-2H-benzotriazole, 2- [2'-hydroxy-5'-(methacryloyloxyethyl) phenyl ] -5-t-Butyl-2H-benzotriazole, 2- [2'-hydroxy-5 '-(methacryloyloxyethyl) phenyl] -5-nitro-2H-benzotriazole and the like, but not limited to Not a thing. One of these ultraviolet absorbing monomers (1) may be used alone, or two or more thereof may be appropriately mixed and used.

The cycloalkyl group-containing unsaturated monomer represented by the general formula according to the present invention (2) (hereinafter, referred to as a cycloalkyl group-containing monomer (2)) are those wherein in R ¹⁰ The compound represented by the formula (1) is a hydrogen atom or a hydrocarbon group having 1 to 2 carbon atoms, and the substituent represented by Z is a cycloalkyl group which may have a substituent.

Specific examples of the cycloalkyl group-containing unsaturated monomer include cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate and cyclododecyl (meth). ) Acrylics and the like are mentioned, but not limited thereto. As the cycloalkyl group-containing monomer, only one type may be used, or two or more types may be appropriately mixed and used.

Specific examples of the hydroxyl group-containing monomer according to the present invention include hydroxyethyl (meth).
Acrylate, hydroxypropyl (meth) acrylate, caprolactone-modified hydroxy (meth) acrylate (for example, trade name Praxel FM, manufactured by Daicel Chemical Industries, Ltd.), mono (meth) acrylate of polyester diol obtained from phthalic acid and propylene glycol, etc. Examples thereof include, but are not limited to, monomers having a hydroxyl group. As the hydroxyl group-containing monomer, only one kind may be used, or two or more kinds may be appropriately mixed and used.

The UV stable monomer represented by the general formula (3) according to the present invention (hereinafter referred to as UV stable monomer (3)) is a substituent represented by R ⁶ in the formula. Is a hydrogen atom or a cyano group, and the substituents represented by R ⁷ and R ⁸ are each independently a hydrogen atom or a carbon number of 1 to 2.
And a substituent represented by R ⁹ is a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, and a substituent represented by Y is an oxygen atom or an imino group. Is. The substituents represented by R ⁷ and R ⁸ are, for example, a hydrogen atom, a methyl group or an ethyl group, and the substituent represented by R ⁹ is, for example, a methyl group. Group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group Group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group and the like.

Specific examples of the UV-stable monomer (3) include 4- (meth) acryloyloxy-2,2,6,6-tetramethylpiperidine and 4- (meth) acryloyl. Amino-2,2,6,6-tetramethylpiperidine, 4-
(Meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- (meth) acryloylamino-1,2,2,6,6
-Pentamethylpiperidine, 4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-
Examples thereof include crotonoyloxy-2,2,6,6-tetramethylpiperidine and 4-crotonoylamino-2,2,6,6-tetramethylpiperidine, but are not particularly limited. As the UV-stable monomer (3), only one kind may be used, or two or more kinds may be appropriately mixed and used.

The UV-stable monomer represented by the general formula (4) according to the present invention (hereinafter referred to as UV-stable monomer (4)) is a substituent represented by R ⁶ in the formula. Is a hydrogen atom or a cyano group, and the substituents represented by R ⁷ and R ⁸ are each independently a hydrogen atom or a carbon number of 1 to 2.
And a substituent represented by Y is composed of an oxygen atom or an imino group.

Specific examples of the above UV stable monomer (4) include 1- (meth) acryloyl-4-
(Meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1 -Crotonoyl-4-crotonoyloxy-2,2,6,6
Examples include, but are not limited to, tetramethylpiperidine and the like. As the UV-stable monomer (4), only one kind may be used, or two or more kinds may be appropriately mixed and used.

The above-mentioned monomers (that is, the ultraviolet absorbing monomer (1), the cycloalkyl group-containing monomer (2), the hydroxyl group-containing monomer, and the ultraviolet stable monomer (3).
Monomers other than (4)), that is, other monomers (hereinafter referred to as other monomers) that are optionally contained in the monomer composition, are used in the monomer composition. The coating composition containing the polymerized copolymer may be any compound that does not impair the required various physical properties.

Specific examples of the other monomers include carboxyl group-containing unsaturated monomers such as (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid and maleic anhydride; vinyl sulfone. Unsaturated monomers containing sulfonic acid groups such as acid, styrene sulfonic acid and sulfoethyl (meth) acrylate; 2- (meth) acryloyloxyethyl acid phosphate, 2- (meth) acryloyloxypropyl acid phosphate, 2- (meth) Acidic phosphoric acid ester unsaturated monomers such as acryloyloxy-3-chloropropyl acid phosphate, 2-methacryloyloxyethyl phenyl phosphoric acid; methyl (meth) acrylate, ethyl (meth) acrylate,
Propyl (meth) acrylate, isopropyl (meth)
(Meth) acrylic acid alkyl ester such as acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate Epoxy group-containing unsaturated monomers such as glycidyl (meth) acrylate; nitrogen-containing unsaturated monomers such as (meth) acrylamide, N, N'-dimethylaminoethyl (meth) acrylate, vinyl pyridine, vinyl imidazole; Halogen-containing unsaturated monomers such as vinyl chloride and vinylidene chloride; styrene,
Examples thereof include aromatic unsaturated monomers such as α-methylstyrene and vinyltoluene; vinyl esters such as vinyl acetate; vinyl ethers; unsaturated cyanide compounds such as (meth) acrylonitrile, etc., but are not particularly limited. As the other monomer, only one kind may be used as necessary, or two or more kinds may be appropriately mixed and used.

The content of each of the above-mentioned monomers in the monomer composition is not particularly limited, but the content of the ultraviolet absorbing monomer (1) is 0.1 to 30% by weight. The range is preferable, the range of 1% by weight to 20% by weight is more preferable, and the range of 2% by weight to 15% by weight is particularly preferable.

When the amount of the ultraviolet absorbing monomer (1) in the monomer composition is less than 0.1% by weight, the ultraviolet absorbing ability of the obtained coating composition becomes insufficient, which is not preferable. On the other hand, when the amount of the UV-absorbing monomer (1) is more than 30% by weight, the gloss and fleshness of the coating film formed from the coating composition are insufficient and the appearance becomes ugly. At the same time, the solvent resistance and chemical resistance are inferior, which is not preferable.

The content of the cycloalkyl group-containing monomer (2) in the monomer composition is preferably in the range of 5% by weight to 98.9% by weight, and more preferably in the range of 5% by weight to 80% by weight. More preferably, the range of 10% by weight to 70% by weight is particularly preferable.

When the amount of the cycloalkyl group-containing monomer (2) in the monomer composition is less than 5% by weight, the coating film formed from the coating composition may have a glossy or thick feeling. It is not preferable because it is insufficient or the synergistic effect with the ultraviolet absorbing monomer (1) is weakened and the weather resistance is not sufficiently exhibited. On the other hand, when the amount of the cycloalkyl group-containing monomer (2) is more than 98.9% by weight, the contents of the ultraviolet absorbing monomer (1) and the hydroxyl group-containing monomer become too small, and the coating composition The weather resistance of the coating film formed from the composition for use is insufficient, and the solvent resistance and chemical resistance are inferior, which is not preferable.

The content of the hydroxyl group-containing monomer in the monomer composition is preferably in the range of 1% by weight to 45% by weight, more preferably 2% by weight to 40% by weight.
Particularly preferably, it is within the range of 35% by weight to 35% by weight.

When the amount of the hydroxyl group-containing monomer in the monomer composition is less than 1% by weight, the number of active hydroxyl groups contained in the obtained copolymer is small and the crosslinking density is low. It is not preferable because the coating film performance cannot be obtained. On the other hand, when the amount of the hydroxyl group-containing monomer is more than 45% by weight, the polymerization stability becomes poor and the water resistance of the obtained coating film is lowered, which is not preferable. In addition, the storage stability after blending the polyisocyanate compound or its modified product is deteriorated, which is not preferable.

The amount of the ultraviolet absorbing monomer (1) and the amount of the cycloalkyl group-containing monomer (2) in the monomer composition,
By setting the amount of the hydroxyl group-containing monomer within the above range, the resulting coating composition may form a coating film having various physical properties such as mechanical properties and acid resistance and long-term weather resistance. it can.

The UV stable monomers (3) and (4) are used, if necessary, within a total content of 20% by weight or less in the monomer composition, but 0.1% by weight or more. By this, the UV stability of the resulting coating composition will be sufficient and long-term weather resistance will be realized. The weight ratio of the UV stable monomer (3) and the UV stable monomer (4) is not particularly limited, and both may be used, or only one may be used. It is particularly preferable to use only the UV stable monomer (3).

In obtaining the above monomer composition, an ultraviolet absorbing monomer (1), a cycloalkyl group-containing monomer (2),
Hydroxyl group-containing monomer, UV stable monomer (3)
The method of mixing (4) and other monomers is not particularly limited. That is, the method for preparing the monomer composition is not particularly limited.

The polymerization method for copolymerizing the monomer composition is not particularly limited, and various conventionally known polymerization methods such as solution polymerization method, emulsion polymerization method, suspension polymerization method, and bulk polymerization method can be used. Although a polymerization method or the like can be adopted, it is preferable to adopt a solution polymerization method.

Solvents that can be used when the monomer composition is copolymerized by employing the solution polymerization method include, for example, toluene, xylene, and other high boiling aromatic solvents; ethyl acetate, butyl acetate. , Ester solvents such as cellosolve acetate; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; aliphatic alcohol solvents such as isopropanol, n-butanol, iso-butanol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol mono Examples thereof include organic solvents such as alkylene glycol monoalkyl ether solvents such as ethyl ether, and water, but are not particularly limited. However, in the coating composition of the present invention, when the copolymer is mixed with a crosslinking agent composed of a polyisocyanate compound or a modified product thereof, among the above-mentioned solvents, an aliphatic alcohol solvent, an alkylene glycol monoalkyl Ether-based solvents or solvents that are active with respect to isocyanate groups such as water are not preferred. One of these solvents may be used alone, or two or more of them may be appropriately mixed and used. Further, the amount of the solvent used is not particularly limited.

When the monomer composition is copolymerized, a polymerization initiator can be used. Examples of the above-mentioned polymerization initiator include 2,2'-azobis- (2-methylbutyronitrile), t-butylperoxy-2-ethylhexanoate, 2,2'-azobisisobutyronitrile. Ordinary radical polymerization initiators such as benzoyl peroxide, di-t-butyl peroxide and the like can be mentioned, but not particularly limited. Further, the amount of the polymerization initiator used is not particularly limited.

When copolymerizing the monomer composition, the reaction temperature is not particularly limited, but is preferably room temperature to 200 ° C, more preferably 40 ° C to 140 ° C. . The reaction time may be appropriately set according to the reaction temperature, the composition of the monomer composition to be used, the type of the polymerization initiator, and the like so that the polymerization reaction is completed.

Further, when copolymerizing the monomer composition, lauryl mercaptan, 2-mercaptoethanol, carbon tetrachloride, for the purpose of adjusting the molecular weight, if necessary.
A chain transfer agent such as carbon tetrabromide or a regulator may be used. That is, the molecular weight of the obtained copolymer is the reaction time, the reaction temperature, or the composition of the monomer composition to be used, the type of the polymerization initiator, and the like, and if necessary, a chain transfer agent or a regulator is used in an appropriate amount. Can be adjusted. The weight average molecular weight (Mw) of the copolymer thus obtained is 2,000 to 30.
It is preferably 0,000, more preferably 8,000 to 100,000.

The crosslinking agent according to the present invention is not particularly limited as long as it is a compound having two or more functional groups capable of reacting with a hydroxyl group in one molecule, and only one kind may be used. Also, two or more kinds may be appropriately mixed and used. When a polyisocyanate compound having two or more isocyanate groups in one molecule or a modified product thereof is used as the above compound, a two-component crosslinkable room temperature curable coating composition that cures at room temperature or a relatively low heating temperature is obtained. It is preferably obtained.

The polyisocyanate compound or a modified product thereof is not particularly limited as long as it has two or more isocyanate groups in the molecule.
Trimethylene diisocyanate, 1,6-hexamethylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, xylylene diisocyanate, metaxylylene diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), and derivatives of these diisocyanates Examples thereof include adduct polyisocyanate compounds such as trimethylolpropane adduct, burette, and isocyanurate. Further, only one kind may be used, or two or more kinds may be appropriately mixed and used.

The compounding amount of the polyisocyanate compound or its modified product with respect to the copolymer in the coating composition of the present invention is not particularly limited.

Further, in the coating composition of the present invention, when a polyisocyanate compound or a modified product thereof is blended with the copolymer, in addition to the copolymer and the crosslinking agent, a hydroxyl group and an isocyanate group in the copolymer are added. Known catalysts for accelerating the urethanization reaction of (for example, dilauric acid di-
organotin compounds such as n-butyltin and tertiary amines),
Various coating additives such as an organic solvent, a filler, a leveling agent, a plasticizer, a stabilizer, a dye and a pigment may be appropriately contained.

As the above pigment, an inorganic pigment or an organic pigment can be used. Examples of the inorganic pigment include white pigments such as titanium oxide, antimony trioxide, zinc white, lithopone, and white lead; colored pigments such as carbon black, yellow lead, molybdenum red, red iron oxide, yellow iron oxide, and yellow flower. . Examples of organic pigments include azo compounds such as benzidine and Hansa Yellow; phthalocyanines such as phthalocyanine blue. Only one type of these pigments may be used, or two or more types may be appropriately mixed and used. The coating composition according to the present invention can have various pigments dispersed therein by a known pigment dispersion method to obtain a colored coating composition, and has excellent dispersibility of pigments such as carbon black. It is also excellent in color mixing stability in a composite pigment system.

The method of blending the copolymer, the cross-linking agent, and various additives when obtaining the coating composition of the present invention is not particularly limited.

As described above, the coating composition according to the present invention contains the ultraviolet absorbing monomer (1), the cycloalkyl group-containing monomer (2), and the hydroxyl group-containing monomer. It is a structure containing a copolymer obtained by copolymerizing a monomer composition.

As a result, it is excellent in transparency, gloss, durability, mechanical strength, acid resistance, solvent resistance, etc.
Especially excellent in ultraviolet absorption ability in the wavelength region of ~ 400 nm, coloring due to the ultraviolet absorbing monomer (1) hardly occurs,
Moreover, it is possible to provide a coating composition capable of forming a coating film excellent in long-term weather resistance such as gloss retention and discoloration resistance in long-term outdoor use.

Further, the coating composition according to the present invention comprises
The above monomer composition is the UV stable monomer (3) and /
Alternatively, the composition further contains an ultraviolet stable monomer (4). As a result, the UV absorbing ability and the UV stability are sufficiently expressed by the synergistic effect of the UV absorbing monomer (1) and the UV stable monomers (3) and (4).
It is possible to form a coating film having further excellent long-term weather resistance.

Furthermore, the coating composition according to the present invention comprises:
A cross-linking agent composed of a polyisocyanate compound or a modified product thereof is added to the above copolymer. This makes it possible to obtain a two-part crosslinkable room temperature curable coating composition having excellent drying properties and excellent coating workability.

The object to be coated with the above coating composition is not particularly limited. Examples of the object to be coated include various plastics such as ABS (acrylonitrile-butadiene-styrene) resin, FRP (fiber reinforced plastic), PET (polyethylene terephthalate), polystyrene, polypropylene, polycarbonate, acrylic resin; various metals; glass. Etc. By coating the coating composition of the present invention on the surface of the article to be coated to form a coating film, the article can be protected from ultraviolet rays. That is, the coating composition of the present invention is for plastic moldings, home appliances,
Widely used as a UV-absorbing coating agent for steel products, large structures, automobiles (for new cars and clear tops for solid color coatings and metallic color coatings for repairs), construction, construction materials, woodworking, etc. can do.

[0058]

[Function] According to the above constitution, it is excellent in transparency, gloss, durability, mechanical strength, acid resistance, solvent resistance and the like, and has an ultraviolet absorbing ability in the wavelength range of 300 nm to 400 nm. It is possible to provide a coating composition capable of forming a coating film which is particularly excellent and has excellent long-term weather resistance such as gloss retention in long-term outdoor use and discoloration resistance.

[0059]

The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these. In the Examples and Comparative Examples, “parts” means “parts by weight”, and “%” means “% by weight”.
Is shown.

Example 1 A four-necked flask equipped with a thermometer, a nitrogen gas introduction tube, a dropping funnel, a condenser and a stirrer was charged with 25 parts of xylene as a solvent and 25 parts of butyl acetate.
A part was charged and the temperature was raised to 100 ° C. On the other hand, 0.1 parts of 2- [2'-hydroxy-5 '-(methacryloyloxyethyl) phenyl] -2H-benzotriazole (hereinafter referred to as benzotriazole (A)) as an ultraviolet absorbing monomer (1), 46.9 parts of cyclohexyl methacrylate as a cycloalkyl group-containing monomer (2), 2.5 parts of hydroxyethyl methacrylate as a hydroxyl group-containing monomer, 0.5 part of methacrylic acid as another monomer, and 2, as a polymerization initiator. A mixed solution in which 0.5 part of 2'-azobisisobutyronitrile (hereinafter referred to as an initiator (a)) was mixed was put in a dropping funnel. Then, this mixed solution was added dropwise at 100 ° C over 2 hours with stirring under a nitrogen gas stream, and further 100 ° C.
The mixture was agitated for 4 hours while maintaining the above temperature to carry out copolymerization. The main reaction conditions are summarized in Table 1.

After completion of the reaction, the viscosity of the obtained copolymer solution was measured by a Gardner foam viscometer to find that Z
⁺ (Symbol of viscosity standard liquid) and nonvolatile content is 49.8
%Met. The weight average molecular weight (Mw) of the obtained copolymer was 15,000.

Then, this copolymer solution was added to a polyfunctional isocyanate (Sumijour N-320) as a crosslinking agent.
0; manufactured by Sumitomo Bayer Urethane Co., Ltd., the equivalent ratio of isocyanate groups to hydroxyl groups in the copolymer is 1: 1.
In an amount of ## EQU1 ## the mixture was weighed and blended to obtain a coating composition.

Further, the obtained coating composition was diluted by adding a thinner of xylene: butyl acetate = 1: 1,
The viscosity of the mixture was adjusted to a viscosity that allowed air spraying. As a result, clear paint was obtained.

The resulting clear paint was air-sprayed onto a white plate obtained by applying a two-component urethane resin enamel onto a zinc phosphate-treated steel plate, and the dry paint film thickness was about 30 μm. It was painted on the white plate surface. Then, this white plate was forcedly dried at 80 ° C. for 60 minutes to prepare a test piece for a fluorescent UV condensation test (QUV test).

Then, using this test piece, the 60 ° gloss value and the yellowing degree (hereinafter referred to as Δb value) were measured. The measurement was carried out based on JIS K 5400-1979, and as a measuring device, Toyo Seiki Seisakusho; Yubucon (UVCON) UC-1 type was used. As the measurement conditions, the cycle of irradiation 70 ° C. × 4 hours and wet 50 ° C. × 4 hours as one set was repeated, and the initial and QUV
After 2000 hours, the 60 ° gloss value and yellowing degree were measured, and the gloss retention rate (hereinafter referred to as GR) after 2000 hours of QUV was determined. As a result, the initial 60 ° gloss value is 93, QU
After 2000 hours, the GR was 93% and the Δb value was 8.

An acid resistance test is conducted as follows.
The evaluation was performed in four grades of "excellent"-"good"-"normal"-"poor". That is, a 5 w / v% sulfuric acid aqueous solution was spotted on the test piece, left at 60 ° C. for 30 minutes, and then visually observed. In this case, no abnormalities were observed in the coating film (four-level evaluation "excellent"). The results of these measurements are summarized in Table 2.

Example 2 The amount of benzotriazole (A) in Example 1 was changed from 0.1 part to 1.0 part, the amount of cyclohexyl methacrylate was changed from 46.9 parts to 28.5 parts, and the amount of hydroxyethyl methacrylate was changed from 2.5 parts to 20.0 parts. To
The same reaction and operation as in Example 1 were carried out except that each was changed to obtain a copolymer solution. The main reaction conditions are summarized in Table 1.

After the completion of the reaction, the viscosity of the obtained copolymer solution was measured by a Gardner foam viscometer to find that it was Z (viscosity standard liquid symbol), and the nonvolatile content was 50.1%. Further, the weight average molecular weight (M
w) was 14,000.

Then, the same operation as in Example 1 was carried out to obtain a coating composition. Further, the same operation as in Example 1 was performed to prepare a test piece, and the initial 60 ° gloss value, QUV 200
The measurement of Δb value and GR after 0 hours and the acid resistance test were performed. The results of these measurements are summarized in Table 2.

Example 3 A 4-necked flask similar to the 4-necked flask of Example 1 was charged with 25 parts of xylene and 25 parts of butyl acetate as a solvent, and the temperature was raised to 100 ° C. On the other hand, 15.0 parts of benzotriazole (A), 14.6 parts of cyclohexyl methacrylate, 8.0 parts of hydroxyethyl methacrylate, 0.5 part of initiator (a), and 0.5 parts of methacrylic acid as other monomer, n-butyl acrylate.
The mixed solution obtained by mixing 1.5 parts was placed in a dropping funnel. Then, while stirring this mixed solution under a nitrogen gas stream, 1
The solution was added dropwise at 00 ° C. over 2 hours, and the resulting solution was stirred for 4 hours while maintaining the temperature at 100 ° C. for copolymerization to obtain a copolymer solution. The main reaction conditions are summarized in Table 1.

After completion of the reaction, the viscosity of the obtained copolymer solution was measured by a Gardner foam viscometer to find Z2.
(Viscosity standard liquid symbol) and non-volatile content is 50.0%
Met. The weight average molecular weight (Mw) of the obtained copolymer was 13,000.

Then, the same operation as in Example 1 was carried out to obtain a coating composition. Further, the same operation as in Example 1 was performed to prepare a test piece, and the initial 60 ° gloss value, QUV 200
The measurement of Δb value and GR after 0 hours and the acid resistance test were performed. The results of these measurements are summarized in Table 2.

Example 4 A four-necked flask similar to the four-necked flask of Example 1 was charged with 25 parts of xylene and 25 parts of butyl acetate as solvents and heated to 100 ° C. On the other hand, benzotriazole (A) 5.0 parts, cyclohexyl methacrylate 34.5 parts, hydroxyethyl methacrylate 8.0 parts, and methacrylic acid 0.5 as other monomers.
Part, initiator (a) 0.5 part, and 4-methacryloyloxy-2,2,6,6-tetramethylpiperidine (hereinafter referred to as piperidine (C)) as an ultraviolet stable monomer (3)
The mixed solution prepared by mixing 2.0 parts was placed in a dropping funnel. Then, this mixture is stirred under a nitrogen gas stream while stirring at 100%.
The mixture was added dropwise at 2 ° C. over 2 hours, and then stirred at 4 ° C. for 4 hours for copolymerization to obtain a copolymer solution. The main reaction conditions are summarized in Table 1.

After completion of the reaction, the viscosity of the obtained copolymer solution was measured by a Gardner foam viscometer to find that Z1 ⁺
(Viscosity standard liquid symbol) and non-volatile content is 49.9%
Met. The weight average molecular weight (Mw) of the obtained copolymer was 14,000.

Then, the same operation as in Example 1 was carried out to obtain a coating composition. Further, the same operation as in Example 1 was performed to prepare a test piece, and the initial 60 ° gloss value, QUV 200
The measurement of Δb value and GR after 0 hours and the acid resistance test were performed. The results of these measurements are summarized in Table 2.

Example 5 A 4-necked flask similar to the 4-necked flask of Example 1 was charged with 25 parts of xylene and 25 parts of butyl acetate as solvents and heated to 100 ° C. On the other hand, a mixed solution obtained by mixing 1.0 part of benzotriazole (A), 29.0 parts of cyclohexyl methacrylate, 20.0 parts of hydroxyethyl methacrylate, and 0.5 part of the initiator (a) was put in a dropping funnel. Thereafter, this mixed solution was added dropwise at 100 ° C. over 2 hours while stirring under a nitrogen gas stream, and further, while maintaining the temperature at 100 ° C., stirring was performed for 4 hours for copolymerization to obtain a copolymer solution. The main reaction conditions are summarized in Table 1.

After completion of the reaction, the viscosity of the obtained copolymer solution was measured by a Gardner foam viscometer to find Z2.
(Viscosity standard liquid symbol) and non-volatile content is 49.9%
Met. The weight average molecular weight (Mw) of the obtained copolymer was 14,000.

Next, the same operation as in Example 1 was carried out to obtain a coating composition. Further, the same operation as in Example 1 was performed to prepare a test piece, and the initial 60 ° gloss value, QUV 200
The measurement of Δb value and GR after 0 hours and the acid resistance test were performed. The results of these measurements are summarized in Table 2.

[Example 6] A 4-necked flask similar to the 4-necked flask of Example 1 was charged with 25 parts of xylene and 25 parts of butyl acetate as a solvent, and the temperature was raised to 100 ° C. On the other hand, a mixed solution prepared by mixing 7.0 parts of benzotriazole (A), 23.0 parts of cyclohexyl methacrylate, 15.0 parts of hydroxyethyl methacrylate, 5.0 parts of piperidine (C), and 0.5 parts of the initiator (a) was put in a dropping funnel. Thereafter, this mixed solution was added dropwise at 100 ° C. over 2 hours while stirring under a nitrogen gas stream, and further, while maintaining the temperature at 100 ° C., stirring was performed for 4 hours for copolymerization to obtain a copolymer solution. The main reaction conditions are summarized in Table 1.

After completion of the reaction, the viscosity of the obtained copolymer solution was measured by a Gardner foam viscometer to find that Z2 ⁺
(Viscosity standard liquid symbol) and non-volatile content is 50.0%
Met. The weight average molecular weight (Mw) of the obtained copolymer was 15,000.

Next, the same operation as in Example 1 was carried out to obtain a coating composition. Further, the same operation as in Example 1 was performed to prepare a test piece, and the initial 60 ° gloss value, QUV 200
The measurement of Δb value and GR after 0 hours and the acid resistance test were performed. The results of these measurements are summarized in Table 2.

Comparative Example 1 A 4-necked flask similar to the 4-necked flask of Example 1 was charged with 25 parts of xylene and 25 parts of butyl acetate as solvents and heated to 100 ° C. On the other hand, instead of the benzotriazole (A) of Example 1, 2- [2′-hydroxy-5 ′-(β
-Methacryloyloxyethoxy) -3'-t-butylphenyl] -4-t-butyl-2H-benzotriazole (hereinafter referred to as benzotriazole (B)) 0.1 part, cyclohexyl methacrylate 46.9 parts, hydroxyethyl methacrylate
2.0 parts, methacrylic acid 0.4 parts, and initiator (a) 0.5
The mixed solution in which the parts were mixed was placed in a dropping funnel. afterwards,
This mixed solution was added dropwise at 100 ° C. over 2 hours while stirring under a nitrogen gas stream, and further, while maintaining the temperature at 100 ° C., stirring was carried out for 4 hours for copolymerization to obtain a copolymer solution. The main reaction conditions are summarized in Table 1.

After completion of the reaction, the viscosity of the obtained copolymer solution was measured by a Gardner foam viscometer to find that Z
⁺ (Symbol of viscosity standard liquid), and non-volatile content is 50.0
%Met. The weight average molecular weight (Mw) of the obtained copolymer was 15,000.

Then, the same operation as in Example 1 was carried out to obtain a coating composition for comparison. Further, the same operation as in Example 1 was performed to prepare a test piece, and the initial 60 ° gloss value, QU
After 2000 hours of V, Δb value and GR were measured and an acid resistance test was performed. The results of these measurements are summarized in Table 2.

Comparative Example 2 A 4-necked flask similar to the 4-necked flask of Example 1 was charged with 25 parts of xylene and 25 parts of butyl acetate as a solvent, and heated to 100 ° C. On the other hand, benzotriazole (B) 5.0 parts, cyclohexyl methacrylate 34.5 parts, hydroxyethyl methacrylate 10.0 parts, methacrylic acid 0.4 parts, piperidine (C) 2.0
And 0.5 part of the initiator (a) were mixed, and the mixture was put into a dropping funnel. Thereafter, this mixed solution was added dropwise at 100 ° C. over 2 hours while stirring under a nitrogen gas stream, and further, while maintaining the temperature at 100 ° C., stirring was performed for 4 hours for copolymerization to obtain a copolymer solution. The main reaction conditions are summarized in Table 1.

After completion of the reaction, the viscosity of the obtained copolymer solution was measured by a Gardner foam viscometer to find that Z1 ⁺
(Viscosity standard liquid symbol) and non-volatile content is 50.1%
Met. The weight average molecular weight (Mw) of the obtained copolymer was 14,000.

Then, the same operation as in Example 1 was carried out to obtain a coating composition for comparison. Further, the same operation as in Example 1 was performed to prepare a test piece, and the initial 60 ° gloss value, QU
After 2000 hours of V, Δb value and GR were measured and an acid resistance test was performed. The results of these measurements are summarized in Table 2.

[0088]

[Table 1]

[0089]

[Table 2]

As is clear from the results shown in Table 2,
The coating film formed from the coating composition of the present invention has a good gloss retention rate and hardly yellows even after 2000 hours of QUV. A coating film made of the coating composition of the present invention has excellent acid resistance. As a result, the coating composition of the present invention has excellent transparency, gloss, durability, mechanical strength, acid resistance, solvent resistance, etc. It is understood that it is possible to form a coating film which is particularly excellent in performance and has excellent long-term weather resistance such as gloss retention and discoloration resistance in long-term outdoor use.

[0091]

As described above, the coating composition of the present invention comprises the ultraviolet absorbing monomer represented by the general formula (1) and the cycloalkyl group represented by the general formula (2). It is a constitution including a copolymer obtained by copolymerizing a monomer composition containing a contained unsaturated monomer and a hydroxyl group-containing monomer.

As a result, it is excellent in transparency, gloss, durability, mechanical strength, acid resistance, solvent resistance, etc.
Particularly excellent in ultraviolet absorption in the wavelength range of 0 nm to 400 nm,
There is an effect that it is possible to provide a coating composition capable of forming a coating film having excellent long-term weather resistance such as gloss retention and discoloration resistance in long-term outdoor use.

Front page continuation (72) Inventor Naka ▲ Saki ▼ Mitsuo 5-8 Nishiomitabicho, Suita City, Osaka Prefecture Nippon Shokubai Co., Ltd.

Claims (4)

[Claims] 1. A compound of the general formula (1) (In the formula, R ¹ represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, R ² represents a linear or branched alkylene group having 1 to 6 carbon atoms, and R ³ represents hydrogen. Represents an atom or a methyl group, and X represents a hydrogen atom, a halogen group, a hydrocarbon group having 1 to 8 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group). A monomer and a general formula (2): (In the formula, R ¹⁰ represents a hydrogen atom or a hydrocarbon group having 1 to 2 carbon atoms, and Z represents a cycloalkyl group which may have a substituent). A coating composition comprising a copolymer obtained by copolymerizing a monomer composition containing a monomer and a hydroxyl group-containing monomer. 2. The above monomer composition has the general formula (3): (Wherein, R ⁶ represents a hydrogen atom or a cyano group, R ^7,
R ⁸ independently represents a hydrogen atom or a hydrocarbon group having 1 to 2 carbon atoms, and R ⁹ is a hydrogen atom or 1 to 18 carbon atoms.
Of the formula (4), wherein Y is an oxygen atom or an imino group) and / or a UV stable monomer represented by the general formula (4) (Wherein, R ⁶ represents a hydrogen atom or a cyano group, R ^7,
R ⁸ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 2 carbon atoms, and Y represents an oxygen atom or an imino group). The coating composition according to claim 1. 3. The coating composition according to claim 1 or 2, wherein the copolymer is blended with a crosslinking agent having two or more functional groups capable of reacting with a hydroxyl group in one molecule. . 4. The coating composition according to claim 3, wherein the crosslinking agent comprises a polyisocyanate compound or a modified product thereof.