JP2007009219A - Coating composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating composition having excellent scratch resistance, causing neither chipping nor crack, and excellent in weather resistance, stain resistance and adhesiveness. <P>SOLUTION: The coating composition comprises a polydimethylsiloxane-based copolymer, caprolactone and siloxane as essential ingredients, wherein the siloxane is introduced in the skeleton of the polydimethylsiloxane-based copolymer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention mainly includes resin molded products indoors and outdoors; automobile bodies; woodwork products such as stairs, floors, and furniture; products such as aluminum wheels and door mirrors that have been subjected to treatments such as plating, vapor deposition, and sputtering; range hoods, The present invention relates to a coating composition used in a field where scratch resistance is required, such as metal products such as kitchen panels for kitchens, stainless steel sinks and bathtubs; inorganic building materials such as ceramics wall materials and entrance floors.

  Since resin molded products such as polycarbonate and acrylic plates lack various physical properties such as hardness, weather resistance, stain resistance, and solvent resistance, surface treatment is usually applied to supplement these physical properties. Such surface treatment includes metal mirror surface treatment such as plating, vapor deposition, and sputtering. However, when the metal mirror surface treatment is performed, the treated film is easily scratched, and the scratch is easily noticeable.

  In addition, range hoods, kitchen panels for kitchens, stainless steel sinks, bathtubs, etc. are easily stained and scratched, and woodwork products such as stairs, floors, furniture, etc. are very easily scratched. On the other hand, for automobile topcoats, in recent years, the trend toward high durability has been increasing so as to maintain the paint appearance of new cars for a long period of time, so scratch resistance that is not damaged by car wash machines or dust is required. ing.

  Conventionally known as scratch-resistant paints are ultraviolet (UV) curable paints, electron beam energy (EB) curable paints, silica-based hard coat agents, two-component acrylic urethane-based soft paints, and the like. Yes.

  However, in the UV curable paint, EB curable paint, and silica-based hard coat agent, the use of a hard monomer for increasing the hardness and the increase in strain at the time of curing shrinkage by increasing the crosslink density, Problems such as poor adhesion and cracking are likely to occur.

  On the other hand, the above-mentioned two-component acrylic urethane-based soft paint has no problems of chipping and cracking, but often has a tacky feeling and has a disadvantage that it is inferior in weather resistance and stain resistance. In order to improve the tackiness, it is conceivable to add polydimethylsiloxane oil to the two-component acrylic urethane-based soft paint. However, the stain resistance cannot be improved, and the adhesion to the substrate is not possible. This causes the problem of lowering.

  Accordingly, an object of the present invention is to provide a coating composition that has excellent scratch resistance, does not cause chipping, cracks, and the like, and is excellent in weather resistance, stain resistance, adhesion, and the like.

  In order to solve the above problems, the present invention provides a coating composition characterized by containing a polydimethylsiloxane copolymer in which polysiloxane is introduced into the skeleton and polycaprolactone. Furthermore, the present invention provides a paint comprising the paint composition and a urethane crosslinking agent and / or a melamine crosslinking agent.

  According to the coating composition of the present invention, a coating film excellent in various physical properties such as stain resistance and weather resistance and particularly excellent in scratch resistance can be obtained.

Hereinafter, the present invention will be described in detail.
The coating composition of the present invention comprises a polydimethylsiloxane copolymer (A), a caprolactone component (B), and a siloxane component (C) as essential components. The siloxane component (C) is introduced into the skeleton of the polydimethylsiloxane copolymer (A).

(A) Polydimethylsiloxane-based copolymer The polydimethylsiloxane-based copolymer (A) in the present invention is a copolymer having a polydimethylsiloxane portion and a polymer chain portion of a vinyl monomer. It may be a coalescence or a graft copolymer.

  The synthesis of the polydimethylsiloxane block copolymer can be performed by (1) living polymerization method, (2) polymer initiator method or (3) polymer chain transfer method. It is preferably carried out by 2) a polymer initiator method or (3) a polymer chain transfer method.

のごとき高分子アゾ系ラジカル重合開始剤を使用してビニルモノマーと共重合させることにより、効率よくブロック共重合体を合成することができる。また、ペルオキシモノマーと不飽和基を有するポリジメチルシロキサンとを低温で共重合させて、過酸化物基を側鎖に導入したプレポリマーを合成し、該プレポリマーをビニルモノマーと共重合させる二段階の重合を行うこともできる。 (2) In the polymer initiator method, for example,

A block copolymer can be efficiently synthesized by copolymerizing with a vinyl monomer using a polymer azo radical polymerization initiator such as Also, a two-stage process in which a peroxy monomer and polydimethylsiloxane having an unsaturated group are copolymerized at a low temperature to synthesize a prepolymer having a peroxide group introduced into a side chain, and the prepolymer is copolymerized with a vinyl monomer. The polymerization can also be carried out.

のごときシリコーンオイルに、ＨＳ−ＣＨ₂ＣＯＯＨや、
ＨＳ−ＣＨ₂ＣＨ₂ＣＯＯＨ等を付加してＳＨ基を有するシリコーン化合物とした後、該ＳＨ基の連鎖移動を利用して該シリコーン化合物とビニルモノマーとを共重合させることにより、ブロック共重合体を合成することができる。 (3) In the polymer chain transfer method, for example,

To silicone oil, such as HS-CH ₂ COOH,
A block copolymer is obtained by adding a HS-CH ₂ CH ₂ COOH or the like to form a silicone compound having an SH group, and then copolymerizing the silicone compound and a vinyl monomer using chain transfer of the SH group. Can be synthesized.

のごときポリジメチルシロキサンのメタクリルエステル等とビニルモノマーとを共重合させることにより、容易にかつ収率良くグラフト共重合体を合成することができる。 On the other hand, for polydimethylsiloxane graft copolymers, for example,

By copolymerizing a methacrylic ester of polydimethylsiloxane and the like with a vinyl monomer, a graft copolymer can be synthesized easily and with a high yield.

Examples of vinyl monomers used in the copolymer with polydimethylsiloxane include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, octyl acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, methyl methacrylate, ethyl methacrylate, n -Butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, styrene, α-methyl styrene, acrylonitrile, methacrylonitrile, Vinyl acetate, vinyl chloride, vinylidene chloride, vinyl Vinyl chloride, vinylidene fluoride, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, maleic anhydride, citraconic acid, acrylamide, methacrylamide, N-methylolacrylamide, N , N-dimethylacrylamide, N, N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate, diacetone acrylamide and the like.
Also, vinyl monomers having an OH group such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, and allyl alcohol can be used. A reaction product with acid, itaconic acid, crotonic acid, maleic acid or the like can also be used.
In addition, the above illustration does not limit the present invention.

のごとき２官能カプロラクトンジオール類や、

のごとき３官能カプロラクトントリオール類、その他４官能カプロラクトンポリオール等を使用することができる。
該カプロラクトン成分（Ｂ）をポリジメチルシロキサン系共重合体（Ａ）の骨格に導入する場合には、ラクトン変成ヒドロキシエチル（メタ）アクリレート類を使用するのが好ましく、例えば、

の構造式で示されるラジカル重合性ポリカプロラクトンが挙げられる。 (B) Caprolactone component As the caprolactone component (B) in the present invention, for example,

Bifunctional caprolactone diols such as

Trifunctional caprolactone triols, other tetrafunctional caprolactone polyols, etc. can be used.
When introducing the caprolactone component (B) into the skeleton of the polydimethylsiloxane copolymer (A), it is preferable to use lactone-modified hydroxyethyl (meth) acrylates.

And radically polymerizable polycaprolactone represented by the structural formula:

(C) Siloxane Component Examples of the siloxane component (C) in the present invention include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltoxioxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, and γ-glycidoxy. Propyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyl Triethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropylmethyldi Hydrolysis products of silane compounds having hydrolyzable silyl groups such as toxisilane, organosilica sols in which fine particles of silicic anhydride are stably dispersed in an organic solvent, or the above hydrolysis having radical polymerizability in the organosilica sol A product obtained by adding a partial hydrolyzate of a silane compound having a functional silyl group can be used. In addition, the above illustration does not limit the present invention.
The siloxane component (C) plays an important role in imparting heat resistance, stain resistance and the like to the resulting coating composition and improving the surface hardness of the coating film.

The polydimethylsiloxane copolymer (A) in the present invention is usually produced by solution polymerization. In this solution polymerization, aromatic hydrocarbon solvents such as toluene and xylene, ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, ester solvents such as ethyl acetate, propyl acetate, isobutyl acetate, and butyl acetate, ethanol, isopropanol Alcohol solvents such as butanol and isobutanol are used alone or as a mixed solvent. If desired, oil-soluble polymerization initiators such as benzoyl peroxide, lauryl peroxide, cumene hydroperoxide, and azobisisobutyronitrile are used. Is used.
The reaction temperature of the solution polymerization is preferably 50 to 150 ° C., and the reaction time is preferably 3 to 12 hours.

  When the siloxane component (C) is introduced into the skeleton of the polydimethylsiloxane copolymer (A), the siloxane component (C) is polymerized when the polydimethylsiloxane copolymer (A) is polymerized. ) May be added for copolymerization.

The amount of the polydimethylsiloxane portion in the polydimethylsiloxane copolymer (A) in which the siloxane component (C) is introduced into the skeleton in the present invention is preferably 1 to 30% by weight, particularly 1 to 20%. It is preferable that it is weight%. This polydimethylsiloxane part has a function of imparting lubricity to the coating film surface and imparting scratch resistance by lowering the coefficient of friction, but if the amount of the polydimethylsiloxane part is less than 1% by weight, such an effect is exerted. On the other hand, if the amount of the polydimethylsiloxane portion exceeds 30% by weight, the stain resistance of the coating film decreases.
The molecular weight of the polydimethylsiloxane portion is preferably about 1000 to 30000, and the molecular weight that is effectively oriented on the surface of the coating film and imparts lubricity is particularly preferably about 5000 to 20000.

  The caprolactone component (B) present individually in the coating composition in the present invention is preferably 5 to 50% by weight in the solid content of the coating. This caprolactone component (B) imparts high rebound resilience and good adhesion to the coating film, and has a function of absorbing the rubbing force by energy elastic deformation when the rubbing force is exerted. When the amount of (B) is less than 5% by weight, the scratch resistance and chipping resistance of the coating film are lowered. On the other hand, when the amount of the caprolactone component (B) exceeds 50% by weight, the stain resistance of the coating film is reduced. Decreases.

  The siloxane component (C) introduced into the skeleton of the polydimethylsiloxane copolymer (A) in the present invention is preferably 1 to 20% by weight in the solid content of the paint. The siloxane component (C) has a function of imparting stain resistance, weather resistance, and heat resistance to the coating film and improving the surface hardness of the coating film, but the amount of the siloxane component (C) is 1 weight. If the amount of siloxane component (C) exceeds 20% by weight, the scratch resistance of the coating film decreases.

In order to cure the coating composition of the present invention, the polydimethylsiloxane copolymer (A) in which the siloxane component (C) is introduced into the skeleton is preferably subjected to urethane crosslinking and / or melamine crosslinking.
In order to urethane-crosslink the polydimethylsiloxane copolymer (A), methylenebis-4-cyclohexylisocyanate, trimethylol of tolylene diisocyanate is added to the polydimethylsiloxane copolymer (A) having an OH group. Propane adduct, hexamethylene diisocyanate trimethylolpropane adduct, isophorone diisocyanate trimethylolpropane adduct, tolylene diisocyanate isocyanurate, hexamethylene diisocyanate isocyanurate, isophorone diisocyanate isocyanurate, hexamethylene diisocyanate Use urethane crosslinkers such as polyisocyanates such as biuret bodies or block isocyanates of the above polyisocyanates It can be.
On the other hand, in order to melamine crosslink the polydimethylsiloxane copolymer (A), a melamine crosslinking agent such as alkoxymethylol melamine can be used.

The coating film obtained by curing the coating composition of the present invention has excellent adhesion to various materials, retains a predetermined surface hardness, and is resistant to scratches, and further self-healing when scratches occur. Also excellent. Moreover, this coating film is excellent also in stain resistance, a weather resistance, heat resistance, etc.
Such coating compositions include resin molded products indoors and outdoors; automobile bodies; woodwork products such as stairs, floors and furniture; products such as aluminum wheels and door mirrors that have been subjected to plating, vapor deposition, sputtering, etc .; range hoods It is suitable as a paint for use in fields where scratch resistance is required, such as metal products such as kitchen panels for kitchens, stainless steel sinks and bathtubs; ceramic building wall materials, inorganic building materials such as entrance floors, and the like.

EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further more concretely, the scope of the present invention is not limited to these Examples.
[Synthesis Example 1]
Synthesis of Siloxane Component B In a 500 ml flask equipped with a stirrer, thermometer, condenser and nitrogen gas introduction tube, 106 parts by weight of ethanol (hereinafter simply referred to as “parts”), 270 parts of methyltrimethoxysilane, γ- Polysiloxane was synthesized by charging 23 parts of methacryloxypropylmethyldimethoxylane, 100 parts of deionized water, 1 part of 1% hydrochloric acid and 0.1 part of hydroquinone monomethyl ether. This was adjusted to 50% with methyl isobutyl ketone to obtain siloxane component B (for copolymerization).

[Synthesis Example 2]
Synthesis of Siloxane Component C Using the same equipment as in Synthesis Example 1, 100 parts of organosilica sol (dispersion medium: methyl isobutyl ketone, solid content: 30%), 1.5 parts of γ-methacryloxypropylmethyldimethoxylane, hydroquinone monomethyl ether 0.01 part and 0.01 part formic acid were charged and reacted at 80 ° C. for 3 hours to obtain a siloxane component C (for copolymerization).

[Synthesis Example 3]
Synthesis of Polydimethylsiloxane Graft Copolymer D Using the same equipment as in Synthesis Example 1, 50 parts of toluene and 50 parts of methyl isobutyl ketone were charged and heated to 80 ° C. Separately, 30 parts of methyl methacrylate, 26 parts of butyl methacrylate, 23 parts of 2-hydroxyethyl methacrylate, 1 part of methacrylic acid and methacrylic modified polydimethylsiloxane (Shin-Etsu Chemical Co., Ltd., X-22-174DX, molecular weight: 5000) 20 parts and 1 part of azobis-2-methylbutyronitrile (manufactured by Nippon Hydrazine Kogyo Co., Ltd., ABN-E) are mixed, and this mixed monomer is dropped into the above mixed solution of toluene and methyl isobutyl ketone over 3 hours. did. Thereafter, the reaction was performed for 6 hours to obtain a polydimethylsiloxane-based graft copolymer D. The obtained graft copolymer D had a solid content of 50% and a viscosity W (Gardner Holtz).

[Synthesis Example 4]
Synthesis of Polydimethylsiloxane Graft Copolymer E The monomer composition is 20 parts methyl methacrylate, 26 parts butyl methacrylate, 23 parts 2-hydroxyethyl methacrylate, 10 parts siloxane component B, 1 part methacrylic acid and one-end methacryl-modified polydimethyl. A polydimethylsiloxane graft copolymer E was synthesized in the same manner as in Synthesis Example 3 except that 20 parts of siloxane (Shin-Etsu Chemical Co., Ltd., X-22-174DX, molecular weight: 5000) was used. The obtained graft copolymer E had a solid content of 50% and a viscosity U (Gardner Holtz).

[Synthesis Example 5]
Synthesis of Polydimethylsiloxane Graft Copolymer F Polydimethylsiloxane graft copolymer F was synthesized in the same manner as in Synthesis Example 4 except that siloxane component C was used instead of siloxane component B. The obtained graft copolymer F had a solid content of 50% and a viscosity T (Gardner Holtz).

[Synthesis Example 6]
Synthesis of Polydimethylsiloxane Graft Copolymer G Using the same equipment as in Synthesis Example 1, 50 parts of toluene and 50 parts of methyl isobutyl ketone were charged and heated to 80 ° C. Separately, methyl methacrylate 27 parts, polycaprolactone methacrylic ester (manufactured by Daicel Chemical Industries, Plaxel FM-5), single-end methacryl-modified polydimethylsiloxane (manufactured by Shin-Etsu Chemical Co., Ltd., X-22-174DX, molecular weight: 5000 ) 20 parts, 17 parts of 2-hydroxyethyl methacrylate, 1 part of methacrylic acid and 1 part of azobis-2-methylbutyronitrile (manufactured by Nippon Hydrazine Kogyo Co., Ltd., ABN-E). The mixture was added dropwise over 2 hours to a mixture of methyl isobutyl ketone. Thereafter, the reaction was performed for 6 hours to obtain a polydimethylsiloxane-based graft copolymer G. The obtained graft copolymer G had a solid content of 50% and a viscosity Y (Gardner Holtz).

The components of the above polydimethylsiloxane block and graft copolymers D to G are shown in Table 1.

[Example 1]
E85 parts of the polydimethylsiloxane block copolymer E obtained in Synthesis Example 4 and 15 parts of a tetrafunctional caprolactone polyol (manufactured by Daicel Chemical Industries, Plaxel 410D, molecular weight: 1000, OH value: 220) are blended and crosslinked. 36 parts of HMDI isocyanurate (Takenate D-170N, solid content: 100%, NCO%: 20.7) was added as an agent, and the resulting paint was polished and dried on mild steel plate and glass plate The film was coated so that the film thickness was 25-30 μm.
The obtained coated plate was dried at 60 ° C. for 1 hour and then allowed to stand at room temperature for 1 week, which was used as a test plate.

[Example 2]
In addition to blending 85 parts of the polydimethylsiloxane block copolymer F obtained in Synthesis Example 5 and 15 parts of the same tetrafunctional caprolactone polyol as in Example 1, HMDI trimethylolpropane adduct (Dainippon Ink Chemical Co., Ltd.) was used as a crosslinking agent. Barnock DN-950 manufactured by Co., Ltd., 62 parts of solid content: 75%, NCO%: 12) is added, and the resulting paint is polished so that the film thickness when dried on a mild steel plate and glass plate is 25-30 μm Painted on.
The obtained coated plate was dried at 60 ° C. for 1 hour and then allowed to stand at room temperature for 1 week, which was used as a test plate.

[Comparative Example 1]
Blended with 85 parts of the polydimethylsiloxane block copolymer D85 obtained in Synthesis Example 3 and 15 parts of polycaprolactone triol (manufactured by Daicel Chemical Industries, Plaxel 308, molecular weight: 850, OH number (KOHmg / g): 195) In addition, 36 parts of the same HMDI isocyanurate body as in Example 1 was added as a cross-linking agent, and the obtained paint was polished and coated on a mild steel plate and a glass plate so that the film thickness when dried was 25 to 30 μm.
The obtained coated plate was dried at 60 ° C. for 1 hour and then allowed to stand at room temperature for 1 week, which was used as a test plate.

[Comparative Example 2]
62 parts of the same HMDI trimethylolpropane adduct as in Example 2 was added as a cross-linking agent to 100 parts of the polydimethylsiloxane block copolymer E100 obtained in Synthesis Example 4, and the resulting paint was polished to a mild steel plate and glass. The plate was painted so that the film thickness upon drying was 25-30 μm.
The obtained coated plate was dried at 60 ° C. for 1 hour and then allowed to stand at room temperature for 1 week, which was used as a test plate.

[Comparative Example 3]
36 parts of the same HMDI isocyanurate body as in Example 1 was added as a cross-linking agent to F100 parts of the polydimethylsiloxane block copolymer F100 obtained in Synthesis Example 5, and the resulting paint was polished to a mild steel plate and glass plate. The coating was performed so that the film thickness during drying was 25 to 30 μm.
The obtained coated plate was dried at 60 ° C. for 1 hour and then allowed to stand at room temperature for 1 week, which was used as a test plate.

[Comparative Example 4]
To 100 parts of the polydimethylsiloxane block copolymer G100 obtained in Synthesis Example 6, 20 parts of a methoxylated methylol melamine (Mitsui Cytec Co., Ltd., Cymel 303, solid content: 100%) as a crosslinking agent was added and obtained. The paint was polished and coated on a mild steel plate and a glass plate so that the film thickness upon drying was 25 to 30 μm.
The obtained coated plate was dried at 150 ° C. for 30 minutes, and this was used as a test plate.

[Comparative Example 5]
Tested in the same manner as in Comparative Example 4 except that 122 parts of IPDI trimethylolpropane adduct block isocyanate (Mitsubishi Chemical Corporation, Mytec BL-280, solid content: 59.4%, NCO%: 6.1) was used as a crosslinking agent. A plate was prepared.

Table 2 shows the constituent components of the paints in Examples 1 and 2 and Comparative Examples 1 to 5 described above.

[Test example]
About the test plates obtained in Examples 1 and 2 and Comparative Examples 1 to 5, adhesion, water resistance, alkali resistance, acid resistance, solvent resistance, impact resistance, flex resistance, scratch resistance, stain resistance The weather resistance and salt water resistance were evaluated. A glass plate test plate was used only for the scratch resistance, and a polished mild steel plate test plate was used for the others.

Adhesion was evaluated by a cross cut cell tape peeling test. The water resistance was evaluated by immersing in water at 40 ° C. for 96 hours. The alkali resistance was evaluated by performing a spot test for 24 hours at 20 ° C. using 0.1 N NaOH. The acid resistance was evaluated by performing a 24 hour spot test at 20 ° C. using 0.1 N H ₂ SO ₄ . Solvent resistance was evaluated by rubbing xylene 100 times. The impact resistance was evaluated by testing using a DuPont impact tester under the conditions of 1/4 φ, 500 g × 50 cm. The bending resistance was evaluated by performing a bending test using a 3 mmφ bar. The scratch resistance was evaluated based on the haze value (%) after rubbing 50 times with a load of 500 g using # 000 steel wool. Contamination resistance was evaluated by exposing the test plate outdoors for 6 months. The weather resistance was evaluated by using a sunshine weatherometer for 2000 hours. The salt water resistance was evaluated by continuously spraying 5% saline at 35 ° C. for 240 hours. The results are shown in Table 3.

  As is clear from Table 3, the coating film of the coating composition of the present invention has adhesion, water resistance, alkali resistance, acid resistance, solvent resistance, impact resistance, flex resistance, scratch resistance, and stain resistance. Excellent in all of weather resistance and salt water resistance.

  The coating composition of the present invention is industrially applicable because it is particularly useful in fields where scratch resistance is required.

Claims (2)

  A coating composition comprising a polydimethylsiloxane copolymer having a siloxane component introduced into a skeleton and a caprolactone component.   A coating composition comprising the coating composition according to claim 1 and a urethane crosslinking agent and / or a melamine crosslinking agent.