JP4283831B2 - Paint composition - Google Patents

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 to maintain the appearance of paints for new vehicles 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 cracks 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 a problem of lowering.

  Accordingly, an object of the present invention is to provide a coating composition which has excellent scratch resistance, is free from 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 is to provide a polydimethylsiloxane copolymer which polycaprolactone component is introduced in the backbone, a coating composition containing the polysiloxane component, more The present invention provides a paint comprising the above-mentioned 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 polycaprolactone component (B), and a polysiloxane component (C) as essential components. The polycaprolactone component (B) is introduced into the backbone 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 carried out by (1) living polymerization method, (2) polymer initiator method or (3) polymer chain transfer method, etc. It is preferably carried out by 2) a polymer initiator method or (3) a polymer chain transfer method.

(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.

(2) 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.

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.

(B) As the polycaprolactone component (B) in polycaprolactone component present invention, for example,

Bifunctional caprolactone diols such as

Trifunctional caprolactone triols, other tetrafunctional caprolactone polyols, etc. can be used.
The polycaprolactone component (B) to be introduced into the backbone of polydimethylsiloxane copolymer (A) is preferably to use a lactone-modified hydroxyethyl (meth) acrylates, e.g.,

And radically polymerizable polycaprolactone represented by the structural formula:

The polysiloxane component (C) in (C) polysiloxane component present invention, for example, tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyl Toki silane, dimethyl dimethoxy silane, dimethyl diethoxy silane, .gamma. Gris Sidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacrylic Roxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropyl A partially hydrolyzed product of a silane compound having a hydrolyzable silyl group such as tildimethoxysilane, an organosilica sol in which fine particles of silicic anhydride are stably dispersed in an organic solvent, or the above-mentioned organosilica sol having radical polymerizability The thing etc. which added the partial hydrolyzate of the silane compound which has a hydrolyzable silyl group can be used. In addition, the above illustration does not limit the present invention.
The polysiloxane component (C) is heat-resistant paint composition obtained by imparting stain resistance, etc., play an important role in 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.

The amount of the polydimethylsiloxane portion in the polycaprolactone component (B) is polydimethylsiloxane copolymer introduced into the skeleton in the present invention (A) is preferably from 1 to 30 wt%, especially 1 to It is preferably 20% by 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.

Skeleton introduced polycaprolactone component of polydimethylsiloxane copolymer (A) (B) in the present invention is preferably from 5 to 50 wt% in solid content. The polycaprolactone component (B), a high impact resilience and good adhesion to impart the coating film, the abrasion force is exerted, but has the function of absorbing the energy elastically deformed該擦excessive force, said poly the amount of caprolactone component (B) is less than 5 wt%, scratch resistance and chipping resistance of the coating film is lowered, whereas, if the amount of the polycaprolactone component (B) exceeds 50 wt%, of the coating Reduces contamination resistance.

Polysiloxane component that is present separately in the coating composition in the present invention (C) is preferably 1 to 20 wt% in solid content. The polysiloxane component (C) is stain resistance of the coating film, weather resistance, has a function of improving the surface hardness of the coating film as well as impart heat resistance, the amount of the polysiloxane component (C) not take effect is sufficiently exerted is less than 1 wt%, whereas, if the amount of the polysiloxane component (C) exceeds 20 wt%, scratch resistance of the paint film is reduced.

To cure the coating composition of the present invention, the above-mentioned polycaprolactone component (B) is a urethane crosslinking and / or melamine crosslinking introduced polydimethylsiloxane copolymer in the backbone of (A) is preferred.
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 paint 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 stirrer polysiloxane component A, a thermometer, the flask 500 ml of capacity equipped with a condenser and a nitrogen gas inlet tube, ethanol 106 parts by weight (hereinafter simply referred to as "parts".), 320 parts of tetraethoxysilane, deionized After 21 parts of water and 1 part of 1% hydrochloric acid were charged and maintained at 85 ° C. for 2 hours, ethanol was recovered while the temperature was raised and maintained at 180 ° C. for 30 minutes. After cooling to give viscous polysiloxane component A (external addition).

[Synthesis Example 2]
In the same manner as in Synthesis Example 1 of the polysiloxane component B, 106 parts of ethanol, 270 parts of methyl trimethoxy silane, .gamma.-methacryloxypropyl methyl dimethoxy run 23 parts, 100 parts of deionized water, 1% hydrochloric acid 1 parts of hydroquinone monomethyl Polysiloxane was synthesized by adding 0.1 part of ether. This was adjusted to 50% with methyl isobutyl ketone, and the polysiloxane component B (for copolymerization).

[Synthesis Example 3]
Using similar equipment as in Synthesis Example 1 of the polysiloxane component C, organosilica sol (dispersion medium: methyl isobutyl ketone, solids: 30%) 100 parts, .gamma.-methacryloxypropyl 1.5 parts dimethoxy run, hydroquinone monomethyl They were charged 0.01 parts of ether and 0.01 parts of formic acid, allowed to react for 3 hours at 80 ° C., to obtain polysiloxane component C (for copolymerization).

[Synthesis Example 4]
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 5]
20 parts of methyl methacrylate synthetic monomer composition of polydimethylsiloxane graft copolymer E, 26 parts of butyl methacrylate, 2-hydroxyethyl methacrylate 23 parts, B10 parts polysiloxane component, 1 part of methacrylic acid and one terminal methacrylic modified poly A polydimethylsiloxane graft copolymer E was synthesized in the same manner as in Synthesis Example 4 except that 20 parts of dimethylsiloxane (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 6]
Synthesis of polydimethylsiloxane graft copolymer F
Except using polysiloxane component C instead of the polysiloxane component B, it was synthesized polydimethylsiloxane graft copolymer F in the same manner as in Synthesis Example 5. The obtained graft copolymer F had a solid content of 50% and a viscosity T (Gardner Holtz).

[Synthesis Example 7]
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 (Daicel Chemical Industries, Plaxel FM-5) 35 parts, one-end methacryl-modified polydimethylsiloxane (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]
With blending A15 parts polysiloxane component obtained in the resulting polydimethylsiloxane block copolymer G85 parts and Synthesis Example 1 In Synthesis Example 7, HMDI isocyanurate (manufactured by Takeda Chemical Industries, Ltd. as a crosslinking agent, 36 parts of Tacnate D-170N, solid content: 100%, NCO%: 20.7) were added, and the obtained paint was polished and coated on a mild steel plate and a glass plate 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 1]
Contains 85 parts of the polydimethylsiloxane block copolymer D85 obtained in Synthesis Example 4 and 15 parts of polycaprolactone triol (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 crosslinking 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]
HMDI trimethylolpropane adduct as a crosslinking agent (Dainippon Ink & Chemicals, Vernock DN-950, solid content: 75%, NCO) was added to the polydimethylsiloxane block copolymer E100 part obtained in Synthesis Example 5 as a crosslinking agent. %: 12) 62 parts were added, and the obtained paint was polished and coated on a mild steel plate and a glass plate 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 crosslinking agent to the polydimethylsiloxane block copolymer F100 obtained in Synthesis Example 6, and the resulting paint was polished to a mild steel plate and glass plate. The coating was applied so that the film thickness during 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 4]
To 100 parts of the polydimethylsiloxane block copolymer G100 obtained in Synthesis Example 7, 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]
Comparative example except that 122 parts of IPDI trimethylolpropane adduct block isocyanate (Mitsubishi Chemical Corporation, Mytec BL-280, solid content: 59.4%, NCO%: 6.1) similar to Example 5 was used as a crosslinking agent. A test plate was prepared in the same manner as in No. 4.

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

[Test example]
For the test plates obtained in Example 1 and Comparative Examples 1 to 5, adhesion, water resistance, alkali resistance, acid resistance, solvent resistance, impact resistance, flex resistance, scratch resistance, stain resistance, weather resistance And the 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 weather resistance and salt water resistance.

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

Claims (2)

A coating composition comprising a polydimethylsiloxane copolymer in which a polycaprolactone component is introduced into a skeleton, and a polysiloxane component.   A coating composition comprising the coating composition according to claim 1 and a urethane crosslinking agent and / or a melamine crosslinking agent.