JPH09241538A - Powder coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a powder coating material which is excellent in flowability, levelling properties, surface lubricity, scratch resistance, and weathering resistance to conventional acrylic powder coating materials and which is useful in applications such as a car body, a car part, a general building materials a steel pipe. and various electric home appliances. SOLUTION: This coating material mainly comprises a silicone-acryl copolymer which is a graft or block copolymer formed from an organopolysiloxane and an acrylic polymer having at least one kind of group selected from among epoxy, hydroxyl, and carboxyl groups attached to side chains and which has a glass transition point of 45 deg.C or higher.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a powder coating material.

[0002]

2. Description of the Related Art Since powder coating does not use a solvent as compared with a solvent-based coating that uses a solvent, there is little risk of environmental pollution or fire, good storage stability, and easy handling such as storage and transportation. It is a coating material whose use amount has been rapidly increasing in recent years because of its possible advantages. Typical powder coatings include three types, polyester type, epoxy type, and acrylic type, which are used properly by taking advantage of their respective characteristics. Among them, JP-B-45-18786 and JP-A-49 Since the acrylic powder coating known in Japanese Patent Publication No. -21448 has the advantages of good weather resistance and high hardness, it is expected to be applied to a coating for passenger car bodies. However, the conventional acrylic powder coating materials have the drawbacks that they have no leveling property and scratch resistance because they are solvent-free, and their improvement has been desired.

[0003]

The silicone of the present invention /
Acrylic-powder coating containing a copolymer as a main component has problems of conventional powder coating, such as fluidity at melting, leveling property,
It is a powder coating that improves the lack of scratch resistance and is useful for applications such as passenger car bodies, passenger car parts, general building materials, steel pipes, and various household electric appliances.

[0004]

The present invention provides a copolymer in which an organopolysiloxane and an acrylic polymer are bonded in a graft or block form, wherein the side chain of the acrylic polymer in the copolymer is Mainly composed of a silicone / acryl-copolymer containing one or more groups selected from an epoxy group, a hydroxyl group and a carboxyl group and having a glass transition temperature of 45 ° C. or higher It concerns powder coatings.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Among the silicone / acryl copolymers of the present invention, the silicone / acryl graft copolymer in which the acrylic polymer is the main chain and the organopolysiloxane is graft-bonded is (A ) 1 in 1 molecule
Organopolysiloxane having one radical-polymerizable group, (B) Epoxy group, radical-polymerizable monomer containing one or more groups selected from hydroxyl group and carboxyl group, and (C) (meth) acryl It can be obtained by radical copolymerizing a radically polymerizable monomer mainly containing an acid ester compound.
[The compound name including the expression (meth) acrylic acid ... Described in the specification of the present invention is methacrylic acid ...
Alternatively, the compound name including the indication of acrylic acid ... The component (A), which is an organopolysiloxane having one radical-polymerizable group in one molecule, is a radical such as an acrylic group, a methacrylic group, a styryl group, a cinnamic acid ester group, a vinyl group or an allyl group. There is no particular limitation except that it has one polymerizable group in one molecule, but it is easy to react when it is copolymerized with the component (B) and the component (C), Considering the ease of synthesis of the organopolysiloxane itself and the performance of the powder coating composition of the present invention, it is a radical polymerizable silicone macromonomer represented by the following general formula (Formula 1) or (Formula 2). Is preferred.

[0006]

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[0007]

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(Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a divalent hydrocarbon group having 1 to 12 carbon atoms and may contain an oxygen atom in the middle, R ³ is a methyl group or trimethylsiloxy) Group, R ⁴ is a monovalent hydrocarbon group having 1 to ⁴ carbon atoms, n is an integer of 3 to 200, and m is an integer of 1 to 3.) Specific examples of R ² are -CH ₂ -,-. (CH ₂ ) ₂ -,-(CH ₂ ) _3- , -C
H ₂ CH (CH ₃ ) CH ₂ -,-(CH ₂ ) ₆ -,-(CH ₂ ) ₁₂ -,-(CH ₂ ) ₂ -O- (C
_{H 2) 3 -, - (} CH 2) 2 -O- (CH 2) 2 -O- (CH 2) 3 - and the like.
Specific examples of R ⁴ include -CH ₃ , -CH ₂ CH ₃ , -CH ₂ CH ₂ CH ₃ ,
Etc. -CH ₂ CH ₂ CH ₂ CH ₃ are exemplified. n represents an integer of 3 to 200, preferably 6 to 100. When n is less than 3, the leveling property and scratch resistance are insufficient, and when it exceeds 200, the transparency of the copolymer and the adhesion to the substrate are deteriorated.

Specific examples of the radically polymerizable silicone macromonomer represented by the above (Chemical formula 1) and (Chemical formula 2) include the compounds represented by the following (Chemical formula 3) to (Chemical formula 10).

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[Chemical 6]

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Further, the leveling property of the powder coating material of the present invention,
A part of the methyl group bonded to the silicon atom in (Chemical Formula 3) to (Chemical Formula 10) is a phenyl group, a vinyl group, a long-chain alkyl group, or fluorine, to the extent that performances such as scratch resistance and weather resistance are not impaired. Those substituted with a substituted alkyl group or the like can also be used.

The radical polymerizable monomer (B) containing one or more groups selected from epoxy groups, hydroxyl groups and carboxyl groups is glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, (meth) acrylic acid, fumaric acid, maleic acid , Succinic acid 2-
(Meth) acryloyloxyethyl, maleic acid 2-
Examples include (meth) acryloyloxyethyl, 2- (meth) acryloyloxyethyl phthalate, and 2- (meth) acryloyloxyethyl hexahydrophthalate. It also includes t-butyl (meth) acrylate that produces a carboxyl group by heating. Two or more of these may be used.

The radical-polymerizable monomer (C) mainly composed of (meth) acrylic acid ester is methyl (meth) acrylate, ethyl (meth) acrylate, n-
Butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, isobornyl (meth) acrylate, trifluoropropyl (meth) Acrylate, perfluorobutylethyl (meth) acrylate, perfluorooctylethyl (meth)
(Meth) acrylic acid ester compounds such as acrylates; styrene or styrene derivatives; acrylamides such as acrylamide, N, N-dimethylacrylamide, N, N-dimethylaminopropylacrylamide, N-isopropylacrylamide, N, N-diethylacrylamide Kinds; vinyltrimethoxysilane, γ-
Radical-polymerizable organic silicon compounds such as (meth) acryloxypropyltrimethoxysilane; acrylonitrile; vinylpyrrolidone; vinyl acetate; radicals such as polyoxyalkylene and polycaprolactone having one radical-polymerizable group in one molecule Polymerizable macromonomers are exemplified, but in consideration of performance such as hardness and scratch resistance of the coating film obtained by the powder coating composition of the present invention, it contains 50% by weight or more of (meth) acrylic acid ester compounds. Preferably. An example of a silicone / acrylic-copolymer in which the acrylic polymer obtained as described above has a main chain and an organopolysiloxane is graft-bonded thereto is represented by the following general formula (formula 11) or (formula 12). Indicate.

[0013]

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Embedded image [Wherein R ¹ is hydrogen or a methyl group, R ² is an alkyl group,
X is hydrogen, hydroxyl group-containing organic group, one of: epoxy-containing organic group, R ³ is a methyl group or trimethylsiloxy group, R ⁴ is a monovalent hydrocarbon group having 1 to 4 carbon atoms, M _e is methyl, n is an integer of 3 to 200, m is an integer of 1 to 3,
Expressing the ratio between x, y, and z as a percentage, x is 0 to 90%,
y is 5 to 50% and z is 5 to 50%. ]

Next, organopolysiloxane is the main chain,
A silicone / acryl-block or graft copolymer in which an acrylic polymer is bonded in a block or graft form is prepared by reacting an epoxy group, a hydroxyl group and a carboxyl group in the presence of an organopolysiloxane (D) having an SH group. By radical-copolymerizing a radical-polymerizable monomer (B) containing one or more groups selected from the group and a radical-polymerizable monomer (C) mainly composed of an ester compound of (meth) acrylic acid Obtainable. Here, the organopolysiloxane (D) having an SH group is not particularly limited in structure as long as it has one or more SH groups in one molecule, but it is easy to synthesize the organopolysiloxane itself and the organopolysiloxane of the present invention. Considering the performance of the powder coating, the following general formula (Formula 13)
It is preferable that the organopolysiloxane represented by

[0015]

Embedded image [Wherein, X and Y are each a methyl group or -C ₃ H ₆ S
H, k is an integer of 3 to 200, L is an integer of 0 to 20, at least 1 X, for Y when L is 0 represents -C ₃ H ₆ SH. ] Here, k represents an integer of 3 to 200, preferably 6 to 100 as described above. When k is less than 3, the leveling property and scratch resistance are insufficient, and when k is more than 200, the transparency and the adhesion to the base material when the powder coating material of the present invention is prepared using the copolymer. Deteriorate. L is 0 to 20 as described above, preferably 0 to
It is an integer of 10, and when L 2 exceeds 20, the leveling property and scratch resistance of the powder coating material of the present invention are insufficient.

Specific examples of the SH group-containing organopolysiloxane represented by the above (Chemical formula 13) include the following (Chemical formula 14) to
The compound shown in (Chemical Formula 20) may be mentioned.

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Further, the leveling property of the powder coating material of the present invention,
A part of the methyl group bonded to the silicon atom of the above (Chemical formula 14) to (Chemical formula 20) is a phenyl group, a vinyl group, a long chain alkyl group, to the extent that performances such as scratch resistance and weather resistance are not impaired.
Those substituted with a fluorine-substituted alkyl group can also be used. However, as shown in (Chemical formula 14) to (Chemical formula 17), S is added to the end.
When it has an H group, it becomes a silicone / acrylic-block copolymer, and when it has an SH group in the side chain as shown in (Chemical Formula 18) to (Chemical Formula 20), the organopolysiloxane is an acrylic polymer having a main chain. To form a graft copolymer in which they are bonded in a graft form. The components (B) and (C) are the same as above. If necessary, the component (A) may be added as a radically polymerizable monomer and copolymerized.
Examples of the silicone / acryl-copolymers obtained as described above, in which the organopolysiloxane is the main chain and the acrylic polymer is polymerized in the form of block or graft, are represented by the following general formulas (Formula 21) to ( 23).

[0018]

[Chemical 21]

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Embedded image [Wherein R ¹ is hydrogen or a methyl group, R ² is an alkyl group,
X represents hydrogen, hydroxyl group-containing organic group, one of: epoxy-containing organic group, M _e is methyl radical, n is an integer of 3 to 200, k is an integer of 3 to 200, L is an integer of from 1 to 20 , X, y is expressed as a percentage, the total value of x in each formula is 0 to 90.
%, The total value of y in each formula is 5 to 50%, and the remaining% value is the number of siloxane units. ]

The silicone / acrylic copolymer of the present invention has a glass transition point because it is used as a powder coating material.
It must be 45 ° C or higher. Glass transition point is 45 ℃
If the amount is less than the range, not only is it difficult to form a powder, but also the storage stability when used as a paint, the fluidity of the powder during coating, and the like deteriorate. The glass transition point of the copolymer can be generally calculated by the following formula, but the glass transition point of the silicone / acryl-copolymer can be calculated by using the component (A) or the component (B) other than the organopolysiloxane (D). Since the glass transition point of the copolymer of the component (C) substantially coincides with that of the copolymer, the components (B) and (C) may be selected so that the glass transition point is 45 ° C. or higher according to the following formula. _{1 / Tg = W 1 / Tg} 1 + W 2 / Tg 2 + W 3 / Tg 3 + W 4 / Tg 4 + ······ [ wherein, Tg monomer 1, monomer 2, monomer 3,
Is a glass transition point (unit: ° K) of the copolymer consisting of W ₁ , W ₂ , W _3, ... And Tg ₁ , Tg ₂ , Tg ₃ ,
Indicates the weight ratio of each monomer in the copolymer (represented by a decimal number) and the glass transition point of each monomer homopolymer. ]

The copolymerization reaction in the present invention includes benzoyl peroxide for both graft copolymerization and block copolymerization.
Organic peroxides such as dicumyl peroxide and lauroyl peroxide; normal azo compounds such as 2,2′-azobis (2-methylbutyronitrile) and 2,2′-azobisisobutyronitrile It is carried out in the presence of a radical polymerization initiator, and any method of solution polymerization, emulsion polymerization, suspension polymerization, and bulk polymerization can be applied.
In the case of an organopolysiloxane having one radical-polymerizable group in one molecule, a chain of butyl mercaptan, dodecyl mercaptan, γ-mercaptopropyltrimethoxysilane, carbon tetrachloride, α-methylstyrene dimer, etc. is used as a molecular weight regulator. A transfer agent may be used.

In the present invention, of these polymerization methods, the solution polymerization method is particularly preferable from the viewpoint that it is easy to adjust the molecular weight of the obtained silicone / acryl-copolymer to the optimum range. As the solvent used in this case, aromatic hydrocarbons such as benzene, toluene and xylene; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate, n-butyl acetate and isobutyl acetate; ethanol. , And a mixture of two or more selected from alcohols such as isopropanol, n-butanol, and isobutanol. Polymerization temperature is 50-180 ℃, especially 60-1
The temperature is preferably in the range of 20 ° C, and under this temperature condition, the polymerization reaction can be completed in about 5 to 10 hours. The method for taking out the copolymer from the copolymer solution is not particularly limited, but a method for evaporating the solvent, water for the copolymer solution,
Examples include a method of adding a poor solvent such as methanol to precipitate a copolymer and drying.

In the copolymerization, the ratio of the component (A), the component (B) and the component (C) or the ratio of the component (D), the component (B) and the component (C) is 5 to 50/5 by weight. ~ 50/0
Is 90 to 90, preferably 10 to 40/10 to 40/20 to 80. If the amount of the component (A) or the component (D) is less than 5, the resulting powder coating will have insufficient leveling properties, scratch resistance, weather resistance, etc., and if it exceeds 50, the hardness will be low and the scratch resistance will be poor. . If the amount of component (B) is less than 5, the crosslink density during curing will be low, and the scratch resistance and weather resistance of the resulting powder coating will be insufficient. If it exceeds 50, the leveling property will be poor. The weight average molecular weight of the silicone / acryl-copolymer in terms of polystyrene by GPC is 3,000 to 100,000, and particularly preferably 5,000 to 50,000. If the weight average molecular weight is less than 3,000, the film-forming property becomes insufficient, so that the scratch resistance is poor, and if it exceeds 100,000, the leveling property becomes poor.

The powder coating composition of the present invention is completed by adding and blending a curing agent to the silicone / acrylic copolymer obtained above. Hardener is Silicone / Acrylic-
Epoxy group of the copolymer, to react with one or more groups selected from the hydroxyl group and the carboxyl group, to be compounded for crosslinking, for example sebacic acid in the case of an epoxy group, 1,10 -Decanedicarboxylic acid, phthalic acid, isophthalic acid, adipic acid, and other dibasic acids having hydroxyl groups, melamine resins, blocked isocyanates, acid anhydrides, and carboxyl groups having bisoxazoline and epoxy resins. Are preferably used.
In the case of a radical-polymerizable monomer which reacts with each other, for example, a silicone / acrylic copolymer obtained by copolymerizing a radical-polymerizable monomer containing an epoxy group and a carboxyl group or a hydroxyl group and a carboxyl group, it is not necessary to use a curing agent. The compounding amount of the curing agent is such that the molar ratio of the reactive group of the silicone / acrylic copolymer to the reactive group of the curing agent is 1 / 0.6 to 1 /.
The amount may be 2.0, preferably 1 / 0.8 to 1 / 1.5.

The powder coating composition of the present invention may further contain, if necessary,
It is also possible to mix pigments, fillers and the like. Examples of the pigment include titanium oxide, zinc oxide, iron oxide, carbon black, chromium oxide green, phthalocyanine green, phthalocyanine blue, phthalonitrile blue,
Ultramarine blue, cadmium pigment, chrome pigment and the like can be mentioned. Examples of the filler include clay, silica, talc, mica, wollastonite and the like.

In the powder coating material of the present invention, the mixture of the silicone / acrylic copolymer, the curing agent, the pigment, the filler, etc. obtained above is premixed with a Henschel mixer or the like and kneaded with an extruder or a cokneader. 100 ~ depending on the machine
It can be melt-kneaded at a temperature around 140 ° C., cooled, finely pulverized by a pulverizer, and classified according to the use to obtain a powder coating having a particle size of 100 to 200 mesh. A known method can be applied to the coating method of the powder coating material, and examples thereof include a thermal spraying method, a fluidized immersion method, an electrostatic fluidized immersion method, and an electrostatic spraying method. The curing conditions vary depending on the combination with the curing agent, but usually 120-
Cured at 200 ° C for 5 to 60 minutes.

[0026]

The present invention will be described in more detail with reference to the following examples. (Synthesis Example 1) 100 parts by weight of methyl ethyl ketone was charged into a glass reactor equipped with a stirrer, a thermometer, a condenser, and a dropping device, heated to 80 ° C., and then radically polymerizable silicone macromonomer 10 represented by the following chemical formula 10 Parts by weight,
35 parts by weight of glycidyl methacrylate, 28 parts by weight of methyl methacrylate, 27 parts by weight of butyl methacrylate,
A mixture of 4 parts by weight of 2,2′-azobisisobutyronitrile and 50 parts by weight of methyl ethyl ketone was added dropwise under aeration of nitrogen over 4 hours. After 2 hours of polymerization at 80 ℃,
Add 1 part by weight of 2'-azobisisobutyronitrile and add 2
Polymerization was carried out for hours. After the polymerization solution was cooled, it was poured into 2,000 parts by weight of water to precipitate the polymer, which was then dried in a vacuum drier at 100 ° C./5 mmHg to obtain a silicone / acryl-graft copolymer. The polystyrene equivalent weight average molecular weight by GPC is 14,000 and the epoxy equivalent is 408
(g / mol), glass transition point by DSC was 49 ° C, and softening point by ring and ball method was 105 ° C.

[0027]

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(Synthesis Example 2) In each raw material of Synthesis Example 1,
10 parts by weight of the radical-polymerizable silicone macromonomer is added to 30 parts by weight of the radical-polymerizable silicone macromonomer represented by the following (Chemical Formula 25), and glycidyl methacrylate.
35 parts by weight to 23 parts by weight, methyl methacrylate 28 parts by weight to 25 parts by weight, butyl methacrylate 27 parts by weight to 22 parts by weight
A silicone / acrylic-graft copolymer was obtained in the same manner as in Synthesis Example 1 except that the amount was changed to parts by weight. GPC
The polystyrene-equivalent weight average molecular weight was 31,000, the epoxy equivalent was 621 (g / mol), the glass transition point was 52 ° C, and the softening point was 103 ° C.

[0029]

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(Synthesis Example 3) In each raw material of Synthesis Example 1,
10 parts by weight of radically polymerizable silicone macromonomer to 30 parts by weight of SH group-containing organopolysiloxane represented by the following (formula 26), 23 parts by weight of glycidyl methacrylate to 23 parts by weight, and 28 parts by weight of methyl methacrylate to 25 parts by weight.
A silicone / acrylic-block copolymer was obtained in the same manner as in Synthesis Example 1 except that 27 parts by weight of butyl methacrylate was changed to 22 parts by weight. The polystyrene-equivalent weight average molecular weight by GPC is 11,500, the epoxy equivalent is 628 (g / mol), the glass transition point is 53 ° C, and the softening point is 95.
° C.

[0031]

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(Synthesis Example 4) In each raw material of Synthesis Example 3,
30 parts by weight of SH group-containing organopolysiloxane are represented by the following chemical formula 27
To 20 parts by weight, add 30 parts by weight of glycidyl methacrylate to 30 parts by weight.
The same procedure as in Synthesis Example 3 was repeated except that 25 parts by weight of methyl methacrylate, 27 parts by weight of methyl methacrylate and 22 parts by weight of butyl methacrylate were changed to 23 parts by weight to obtain a silicone / acryl-graft copolymer. It was The polystyrene equivalent weight average molecular weight by GPC is 29,000, and the epoxy equivalent is
The glass transition point was 480 (g / mol), the glass transition point was 50 ° C, and the softening point was 115 ° C.

[0033]

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(Synthesis Example 5) In each raw material of Synthesis Example 1,
Glycidyl methacrylate 35 parts by weight to 2-hydroxyethyl methacrylate 10 parts by weight, methyl methacrylate 28 parts by weight to 40 parts by weight, butyl methacrylate
A silicone / acrylic-graft copolymer was obtained in the same manner as in Synthesis Example 1 except that 27 parts by weight was changed to 40 parts by weight. G
Polystyrene equivalent weight average molecular weight by PC is 18,00
0, hydroxyl equivalent is 1,380 (g / mol), glass transition point is 55
The softening point was 100 ° C.

(Synthesis Example 6) In each raw material of Synthesis Example 3,
23 parts by weight of glycidyl methacrylate to 10 parts by weight of 2-hydroxyethyl methacrylate, 25 parts by weight of methyl methacrylate to 30 parts by weight, butyl methacrylate
A silicone / acrylic-block copolymer was obtained in the same manner as in Synthesis Example 3 except that 22 parts by weight was changed to 30 parts by weight. G
Polystyrene-equivalent weight average molecular weight of 12,00
0, hydroxyl equivalent is 1,405 (g / mol), glass transition point is 52
The softening point was 98 ° C.

(Synthesis Example 7) 35 parts by weight of glycidyl methacrylate of Synthesis Example 1 was changed to 8 parts by weight of acrylic acid, 28 parts by weight of methyl methacrylate was changed to 40 parts by weight, and 27 parts by weight of butyl methacrylate was changed to 42 parts by weight. A silicone / acrylic-graft copolymer was obtained in the same manner as in Synthesis Example 1 except for the above. The polystyrene-converted weight average molecular weight by GPC was 16,500, the carboxy equivalent was 932 (g / mol), the glass transition point was 58 ° C., and the softening point was 116 ° C.

(Synthesis Example 8) 23 parts by weight of glycidyl methacrylate of Synthesis Example 3 was changed to 10 parts by weight of acrylic acid, 25 parts by weight of methyl methacrylate was changed to 20 parts by weight, and 22 parts by weight of butyl methacrylate was changed to 40 parts by weight. A silicone / acrylic-block copolymer was obtained in the same manner as in Synthesis Example 3 except for the above. The polystyrene-converted weight average molecular weight by GPC was 13,000, the carboxy equivalent was 728 (g / mol), the glass transition point was 48 ° C., and the softening point was 110 ° C.

(Epoxy Equivalent Measuring Method) About 2 g of a sample was accurately weighed and placed in a 100 ml stoppered flask, and 10 ml of hydrochloric acid-
Dioxane solution (1.5 ml of concentrated hydrochloric acid just before use was diluted with 100 ml of purified dioxane) was added, dissolved and allowed to stand for 10 minutes. About 20 to 30 ml of neutral ethyl alcohol was added, and excess hydrochloric acid was added to phenolphthalene. As an indicator,
Titrate with 0.1N caustic soda solution. Separately, perform a blank test in the same manner. Epoxy equivalent (g / mol) = 10,000 W / F × (B + AW-T) W: g number of sample weighed A: ml number of 0.1N caustic soda solution required to neutralize 1 g sample B: blank test Number of ml of 0.1N caustic soda solution required T: Number of ml of 0.1N caustic soda solution used for back titration F: Factor of 0.1N caustic soda solution

(Hydroxyl equivalent measuring method) Calculated by the following formula from the hydroxyl value of JIS K0070. Hydroxyl equivalent (g / mol) = 56,100 / hydroxyl value

(Carboxy equivalent measurement method) (1): Weigh 30 ml of a 2: 1 (volume ratio) mixture of toluene: ethanol in a clean Meyer flask (volume 100 ml), and titrate with 0.5N ethanol potassium hydroxide solution. . (2): Accurately weigh about 4 g of the sample in a clean Meyer flask (volume 100 ml), add 30 ml of a 2: 1 (volume ratio) mixture of toluene: ethanol, and stir it sufficiently.
Next, titrate with 0.5N ethanol potassium hydroxide solution,
It is calculated by the following equation. Carboxy equivalent (g / mol) = W × 1,000 / 0.5 × F × [BA] A: Number of ml of 0.5N ethanol potassium hydroxide solution required for blank test B: Required for neutralizing about 4 g of sample Number of ml of 0.5N ethanol potassium hydroxide solution W: Number of g of sample weighed F: Factor of 0.5N ethanol potassium hydroxide solution

Comparative Synthesis Example 1 Without using the radically polymerizable silicone macromonomer of Synthesis Example 1, methyl methacrylate was changed from 28 parts by weight to 35 parts by weight, and butyl methacrylate was changed from 27 parts by weight to 30 parts by weight. Acrylic copolymers were obtained in the same manner as in Synthesis Example 1 except for the above. GP
The polystyrene-converted weight average molecular weight by C is 9,200,
The epoxy equivalent was 405 (g / mol), the glass transition point was 53 ° C, and the softening point was 100 ° C.

COMPARATIVE SYNTHESIS EXAMPLE 2 Methyl methacrylate was changed from 40 parts by weight to 45 parts by weight and butyl methacrylate was changed from 40 parts by weight to 45 parts by weight without using the radical-polymerizable silicone macromonomer of Synthesis example 5. An acrylic copolymer was obtained in the same manner as in Synthesis Example 5 except for the above. The polystyrene-equivalent weight average molecular weight by GPC was 13,000, the hydroxyl equivalent was 1,360 (g / mol), the glass transition point was 58 ° C, and the softening point was 96 ° C.

COMPARATIVE SYNTHESIS EXAMPLE 3 Without using the radical-polymerizable silicone macromonomer of Synthesis Example 7, methyl methacrylate was changed from 40 parts by weight to 45 parts by weight, and butyl methacrylate was changed from 42 parts by weight to 47 parts by weight. Acrylic copolymers were obtained in the same manner as in Synthesis Example 7 except for the above. GPC
The polystyrene-equivalent weight average molecular weight was 11,000, the carboxy equivalent was 920 (g / mol), the glass transition point was 60 ° C, and the softening point was 108 ° C.

The raw material composition (parts by weight), the weight average molecular weight, and the reactive group equivalent of the silicone / acrylic copolymers obtained in each synthesis example and the acrylic copolymer obtained in the comparative synthesis example,
The glass transition point and the softening point are shown in each (Table 1).

Example 1 100 parts by weight of the silicone / acrylic copolymer obtained in Synthesis Example 1, 28 parts by weight of 1,10-decanedicarboxylic acid and 100 parts of titanium dioxide (rutile type).
After preliminarily mixing parts by weight with a Henschel mixer, the mixture was kneaded at 120 ° C. in an extruder, cooled, pulverized with a high-speed rotary pulverizer, and further classified to obtain a 150-mesh pass powder coating. Next, this powder coating was adhered to a zinc phosphate-treated iron plate by a fluidized-bed method, and then baked at 180 ° C. for 20 minutes. The raw material composition of the powder coating material and the physical properties of the coating film obtained are shown in Table 2. The source of the used curing agent and the method for measuring the physical properties of the powder coating material are described in paragraph [0050].

(Examples 2-8) Silicone of Synthesis Example 1 /
The acrylic-copolymer and the curing agent were changed as shown in (Table 2), and the raw material composition of the powder coating material and the physical properties of the obtained coating film were measured in the same manner as in Example 1 and the results are shown in the same manner (Table 2). 2). The silicone used in each example /
The acrylic-copolymer used had the number of each synthesis example corresponding to the example number. Similarly, as the acrylic copolymer used in Comparative Examples, those having the numbers of the respective Comparative Synthesis Examples corresponding to the respective Comparative Example numbers were used.

Comparative Examples 1 to 3 Silicone of Example 1 /
Powder coatings were obtained in the same manner as in Example 1 except that the acrylic copolymers were changed to the acrylic copolymers of Comparative Synthesis Examples 1 to 3. The raw material compositions of these powder coatings and the results of the tests conducted in the same manner as in Example 1 are shown in (Table 2).

[0048]

[Table 1]

[0049]

[Table 2]

(Curing agent) 1,10-decanedicarboxylic acid: Enter (a) in (Table 2). Millionate MS-50: manufactured by Nippon Polyurethane Industry Co., Ltd. MDI block isocyanate, effective NC
O (%) 15.1-17.1; Enter (b) in (Table 2). Epicron N-695: Dainippon Ink and Chemicals, Inc. epoxy resin, epoxy equivalent 210-250;
In Table 2, enter (c). (Physical property measuring method) Water repellency: The contact angle (degree) of water evaluated. Scratch resistance: Tissue paper was rolled, and the surface condition when rubbed with a load of about 500 g was observed and evaluated according to the following criteria. No scratches 〇 Slightly scratches △ Scratches × Leveling property: evaluated according to the following criteria. No unevenness on the surface 〇 Slightly unevenness △ There is unevenness × Weather resistance: Sunshine weather meter (JIS B-7753)
The 60-degree specular gloss value after exposure for 500 hours was measured by the above, and the gloss retention rate was calculated from this and the initial gloss value.

[0051]

Industrial Applicability The present invention is a powder coating material containing a silicone / acrylic copolymer in which an organopolysiloxane and an acrylic polymer are bonded in a graft or block form as a main component. Is superior in leveling property, scratch resistance, and weather resistance to

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[Procedure amendment]

[Submission date] January 31, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Among the silicone / acryl copolymers of the present invention, the silicone / acryl graft copolymer in which the acrylic polymer is the main chain and the organopolysiloxane is graft-bonded is (A ) 1 in 1 molecule
Organopolysiloxane having one radical-polymerizable group, (B) Epoxy group, radical-polymerizable monomer containing one or more groups selected from hydroxyl group and carboxyl group, and (C) (meth) acryl It can be obtained by radical copolymerizing a radically polymerizable monomer mainly containing an acid ester compound.
[The compound name including the expression (meth) acrylic acid ... Described in the specification of the present invention is methacrylic acid ...
Alternatively, the compound name including the indication of acrylic acid ... The component (A), which is an organopolysiloxane having one radical-polymerizable group in one molecule, is an acrylic group, a methacrylic group, or 4-vinylphenyl.
Group , a cinnamic acid ester group, a vinyl group, an allyl group, and the like, but not particularly limited to those having one radically polymerizable group in one molecule, but these are the (B) component and the (C) component. Considering the easiness of reaction in the case of copolymerization with the organopolysiloxane itself as the component (A), the performance of the powder coating composition of the present invention, and the like, the following general formula (Formula 1)
Alternatively, the radical-polymerizable silicone macromonomer represented by (Chemical Formula 2) is preferable.

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Further, the leveling property of the powder coating material of the present invention,
A part of the methyl group bonded to the silicon atom of (Chemical Formula 3) to (Chemical Formula 10) is a phenyl group, a long-chain alkyl group, or a fluorine-substituted alkyl group so long as the performance such as scratch resistance and weather resistance is not impaired. It is also possible to use the one replaced with.

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[0013]

Embedded image

Embedded image [Wherein R ¹ is hydrogen or a methyl group, R ⁵ is an alkyl group,
X is hydrogen, hydroxyl group-containing organic group, one of: epoxy-containing organic group, R ³ is a methyl group or trimethylsiloxy group, R ⁴ is a monovalent hydrocarbon group having 1 to 4 carbon atoms, M _e is methyl, n is an integer of 3 to 200, m is an integer of 1 to 3,
Expressing the ratio between x, y, and z as a percentage, x is 0 to 90%,
y is 5 to 50% and z is 5 to 50%. ]

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Embedded image [Wherein Y and Z are each a methyl group or -C ₃ H ₆ S
H, k is an integer of 3 to 200, L is an integer of 0 to 20, at least 1 Y, and Z when the L 0 represents -C ₃ H ₆ SH. ] Here, k represents an integer of 3 to 200, preferably 6 to 100 as described above. When k is less than 3, the leveling property and scratch resistance are insufficient, and when k is more than 200, the transparency and the adhesion to the base material when the powder coating material of the present invention is prepared using the copolymer. Deteriorate. L is 0 to 20 as described above, preferably 0 to
It is an integer of 10, and when L 2 exceeds 20, the leveling property and scratch resistance of the powder coating material of the present invention are insufficient.

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Further, the leveling property of the powder coating material of the present invention,
A part of the methyl group bonded to the silicon atom in the above (Chemical formula 14) to (Chemical formula 20) is a phenyl group, a long chain alkyl group, or a fluorine-substituted alkyl group to the extent that the performance such as scratch resistance and weather resistance is not impaired. It is also possible to use the one replaced with. However, in the case where the compound has an SH group at the terminal as in (Chemical formula 14) to (Chemical formula 17), it becomes a silicone / acryl-block copolymer, and an SH group is added to the side chain as in (Chemical formula 18) to (Chemical formula 20). When it has, it becomes a graft copolymer in which an organopolysiloxane is a main chain and an acrylic polymer is bonded in a graft form. The components (B) and (C) are the same as above. If necessary, the component (A) may be added as a radically polymerizable monomer and copolymerized. Examples of the silicone / acryl-copolymers obtained as described above, in which the organopolysiloxane is the main chain and the acrylic polymer is polymerized in the form of block or graft, are represented by the following general formulas (Formula 21) to ( 23).

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[Chemical 21]

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Embedded image [Wherein R ¹ is hydrogen or a methyl group, R ⁵ is an alkyl group,
X represents hydrogen, hydroxyl group-containing organic group, one of: epoxy-containing organic group, M _e is methyl radical, n is an integer of 3 to 200, k is an integer of 3 to 200, L is an integer of from 1 to 20 , X, y is expressed as a percentage, the total value of x in each formula is 0 to 90.
%, The total value of y in each formula is 5 to 50%, and x + y ≦ 95
It is . The residual% value is the number of siloxane units. ]

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(Epoxy Equivalent Measuring Method) About 2 g of a sample was accurately weighed and placed in a 100 ml stoppered flask, and 10 ml of hydrochloric acid-
Dioxane solution (1.5 ml of concentrated hydrochloric acid just before use was diluted with 100 ml of purified dioxane) was added, dissolved and allowed to stand for 10 minutes. About 20 to 30 ml of neutral ethyl alcohol was added, and excess hydrochloric acid was added to phenolphthalene. As an indicator,
Titrate with 0.1N caustic soda solution. Separately, perform a blank test in the same manner. Epoxy equivalent (g / mol) = 10,000 W / F × (B + WT) W: g number of sample weighed B: ml number of 0.1N caustic soda solution required for blank test T: 0.1N caustic soda used for back titration Number of ml of solution F: Factor of 0.1N caustic soda solution

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COMPARATIVE SYNTHESIS EXAMPLE 3 Without using the radical-polymerizable silicone macromonomer of Synthesis Example 7, methyl methacrylate was changed from 40 parts by weight to 45 parts by weight, and butyl methacrylate was changed from 42 parts by weight to 47 parts by weight. Acrylic copolymers were obtained in the same manner as in Synthesis Example 7 except for the above. GPC
The polystyrene-equivalent weight average molecular weight was 11,000, the carboxy equivalent was 920 (g / mol), the glass transition point was 60 ° C, and the softening point was 108 ° C. (Comparative Synthesis Example 4) The methyl methacrylate of Synthesis Example 1 was
From 28 parts by weight to 12 parts by weight, 27 parts of butylmethacrylate are added.
Same as Synthesis Example 1 except that the weight part was changed to 43 parts by weight.
Then, an acrylic copolymer was obtained. Police by GPC
The weight average molecular weight in terms of ethylene is 15,300, and the epoxy equivalent is
402 (g / mol), glass transition point 39 ° C, softening point 80 ° C
Was.

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[Table 1]

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─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location C09D 151/00 PGX C09D 151/00 PGX 153/00 PGY 153/00 PGY 183/10 PMS 183/10 PMS (72) Inventor Mitsuhiro Takarada 1 Hitomi, Oita, Matsuida-cho, Usui-gun, Gunma 10 Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Technology Laboratory

Claims (3)

[Claims] 1. A copolymer in which an organopolysiloxane and an acrylic polymer are bonded in a graft form or a block form, wherein the side chain of the acrylic polymer in the copolymer contains an epoxy group, a hydroxyl group and a carboxyl group. It contains one or more groups selected from the group, and has a glass transition point
A powder coating containing a silicone / acrylic copolymer as a main component, which has a temperature of 45 ° C. or higher. 2. A silicone / acrylic copolymer selected from (A) an organopolysiloxane having one radical-polymerizable group in one molecule, (B) an epoxy group, a hydroxyl group and a carboxyl group. Alternatively, it is a silicone / acrylic-graft copolymer obtained by radical-polymerizing a radical-polymerizable monomer having two or more kinds of groups and a radical-polymerizable monomer mainly containing an ester compound of (C) (meth) acrylic acid. The powder coating material according to claim 1. 3. A silicone / acryl copolymer in the presence of (D) an organopolysiloxane having an SH group, (B) one or more groups selected from an epoxy group, a hydroxyl group and a carboxyl group. A radical-polymerizable monomer containing (C) and a radical-polymerizable monomer containing (C) an ester compound of (meth) acrylic acid as a main component, which is a silicone / acrylic block or graft copolymer. The powder coating material according to claim 1.