JPH07196975A - Weather-resistant coating composition - Google Patents

Abstract

PURPOSE:To provide a new coating composition excellent in weather resistance, durable water repellency, ultraviolet resistance and antistaining properties by adding a copolymer prepared from a specific long-chain dimethylpolysiloxine to an acrylic resin. CONSTITUTION:The composition is mainly composed of a mixture of (A) 100 pts.wt., on the solid basis, of an acrylic resin and (B) 10 to 200 pts.wt., on the solid basis of a copolymer from an organo-polysiloxane of the formula (R<1> is H, methyl; R<2> is a 1 to 12C difunctional hydrocarbon; R<3> is a 1 to 6C monofunctional hydrocarbon; m is 1 to 3; n is 3 to 200) and other radical- copolymerizable monomers, suitably a monomer mainly bearing (meth)acrylate group such as methyl (meth)acrylate. The component A is preferably a moisture- curing acrylic resin bearing 1 to 30wt.% of hydrolyzable silyl groups such as a dimethylsilyl group. The component B is preferably prepared by the solution polymerization.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a weather resistant coating composition having improved water repellency, stain resistance and acid resistance.

[0002]

2. Description of the Related Art As a coating composition, a coating material which is curable at room temperature and has high weather resistance is required in order to save energy and rationalize a coating process. Further, in recent years, the coating film is apt to become dirty due to air pollution, and the deterioration of the coating film due to acid rain has been pointed out, and acid-resistant and stain-resistant coating materials have been earnestly desired.

[0003]

Generally, an acrylic resin is used as a paint having excellent weather resistance, and is applied over a wide range such as automobiles, building exteriors and bridges. These acrylic paints are crosslinked with an isocyanate compound or a melamine resin to have durability, but isocyanate is being withheld due to reasons such as irritation to the skin, and melamine is triazine due to acid rain. It is not preferable because it is cleaved to reduce gloss. Environment issues,
Water-based acrylic paints are also widely used from the viewpoint of air pollution and safety, but the hardness of the coating film is low and stains easily occur,
It also has poor decontamination properties and long-term weather resistance cannot be expected.
In order to solve the above problems, a method of using a copolymer of γ-methacryloxypropyltrimethoxysilane and another radically polymerizable monomer has been proposed (JP-A-57).
-36109 and JP-A-58-155666), but this is not sufficiently satisfactory in water repellency, acid rain resistance, etc. due to the small number of siloxane bonds, and the disadvantage that the gloss reduction is large due to long-term UV exposure. there were. Fluorine-containing copolymers have been proposed (see Japanese Patent Application Laid-Open No. 57-34107), which show little decrease in gloss against long-term exposure to ultraviolet rays, but use of an isocyanate compound or melamine resin as a cross-linking agent. From the above, it is pointed out that not only the above-mentioned problems have not been completely solved, but also that the coating film hardness is lower than that of other acrylic paints, and that they are easily stained.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to a weather-resistant coating composition which solves the above disadvantages, which is an organopolysiloxane compound having a structure of the following general formula (1) in an acrylic resin. And a blend of a copolymer obtained by polymerizing the organopolysiloxane with another radically polymerizable monomer which is copolymerizable, as a main resin component.

[Chemical 2] (R ¹ is hydrogen or a methyl group, R ² is a divalent hydrocarbon group having 1 to 12 carbon atoms which may be interrupted by an oxygen atom, and R ³ is 1 carbon atom.
6 monovalent hydrocarbon groups, m is 1, 2 or 3 and n is 3 to
It is an integer of 200. )

That is, the inventors of the present invention have weather resistance, water repellency,
As a result of various studies on the acquisition of a coating composition having excellent stain resistance, acrylic resin, especially hydrolyzable silyl group
A copolymer obtained by copolymerizing a long-chain dimethylpolysiloxane compound represented by the general formula (1) with another radically polymerizable monomer in a moisture-curable acrylic resin or water-based acrylic resin emulsion containing two or more molecules in a molecule. It has been found that the object of the present invention can be achieved by applying a coating composition containing a polymer as a main resin component to a substrate and curing it, and the cured coating film has excellent weather resistance. Since it has long-chain dimethylpolysiloxane in the surface layer, it has high UV resistance and high gloss retention, and also has stain resistance, stain removal, water repellency, waterproofness, anti-icing property, and acid resistance. I found that Furthermore, since it has particularly high weather resistance and water repellency, and is most suitable as an outdoor paint, it can be used for construction, automobiles, railroad cars, aircraft, ships, bridges, plants, and even electricity. It was confirmed to be useful for products, and the present invention was completed by conducting research on the type, compounding ratio, reaction conditions, etc. of this siloxane-containing copolymer.

The acrylic resin which is the basic resin constituting the weather resistant coating composition of the present invention includes acrylate and / or
Alternatively, a homopolymer or copolymer of a radical-polymerizable monomer mainly containing methacrylate is used, and solution polymerization,
There is no particular limitation as long as it is polymerized by a method such as solid phase polymerization or emulsion polymerization. However, a moisture-curable acrylic resin containing two or more hydrolyzable silyl groups in one molecule is particularly preferable. The upper limit of the hydrolyzable silyl group in one molecule is not particularly limited, but a hydrolyzable silyl group such as a dimethoxysilyl group or a trimethoxysilyl group at the end of the molecular chain and / or the side chain of the molecule may be added to 1 to 1 of the polymer units. An acrylic resin containing about 30 mol% is preferable. That is, the alkoxysilane compound having a radically polymerizable group represented by the general formula (2) or (3) is used as a copolymerization component.

[0007]

[Chemical 3] (X is a radically polymerizable group, R ² is a divalent hydrocarbon group having 1 to 12 carbon atoms which may be interrupted by an oxygen atom, R ⁵ and R ⁶ are each a monovalent hydrocarbon group having 1 to 6 carbon atoms, k represents an integer of 1 to 3.)

As a specific example of X, CH ₂ = CHCOO-, CH ₂ = C
_{(CH 3) COO-, CH 2} = CHOOC-, CH 2 = CHO-, CH 2 = CH-,

[Chemical 4] Etc. Specific examples of R ² include -CH ₂ -,-(CH ₂ ) _{3
-, - (CH 2) 4} -, -CH 2 CH 2 O (CH 2) 3 -, - (CH 2 CH 2 O) 2 (CH 2) 3 -
Etc., specific examples of R ⁵ and R ⁶ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group,
Examples thereof include a phenyl group.

Specific examples of the alkoxysilane compound having a radical polymerizable group include the following. CH ₂ = CHCOOC ₃ H ₆ Si (OCH ₃ ) ₃ , CH ₂ = C (CH ₃ ) COOC ₃ H ₆ Si (OC
_{H 3) 3, CH 2 =} C (CH 3) COOC 3 H 6 Si (CH 3) (OCH 3) 2, CH 2 = C (CH 3) CO
_{OC 3 H 6 Si (CH 3} ) 2 OCH 3, CH 2 = C (CH 3) COOC 2 H 4 OC 3 H 6 Si (OCH 3) 3,
CH ₂ = C (CH ₃ ) COOC ₁₂ H ₂₄ Si (OCH ₃ ) ₃ , CH ₂ = CHOC ₃ H ₆ Si (CH ₃ ) (O
C ₂ H ₅ ) ₂ , CH ₂ = CHSi (OCH ₃ ) _3, CH ₂ = CHSi (OC ₂ H ₅ ) _3, CH ₂ = CHSi
(C ₄ H ₉ ) (OC ₄ H ₉ ) ₂ ,

[Chemical 5]

Examples of the acrylate and / or methacrylate with which the alkoxysilane is copolymerized include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate and butyl (meth) acrylate. These can be copolymerized in combination with the monomers shown below. 2-hydroxyethyl (meth) acrylate as a monomer that can be used in combination,
(Meth) acrylamide, N-methylol (meth) acrylamide, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, (meth) acrylic acid, vinylpyrrolidone, vinylpyridine, vinyl acetate, styrene, α-methylstyrene , Maleic anhydride, etc. are exemplified. Note that (meth) acrylic is a general term for acrylic and methacrylic.

Next, an organopolysiloxane compound, which is added to the acrylic resin and imparts weather resistance, water repellency, stain resistance, and the like, and another radically polymerizable monomer copolymerizable with the organopolysiloxane are added. A copolymer obtained by radical polymerization is a copolymer obtained by radically copolymerizing an organopolysiloxane compound having one radical-polymerizable group in one molecule with another radical-polymerizable monomer. It is a silicone-based graft copolymer. 1
As the organopolysiloxane compound having one radical-polymerizable group in the molecule, a radical-polymerizable silicone macromer having the structure of the following general formula (1) is used. Hereinafter, the compound represented by the general formula (1) is simply referred to as a silicone macromer.

[Chemical 6] (R ¹ is hydrogen or a methyl group, R ² is a divalent hydrocarbon group having 1 to 12 carbon atoms which may be interrupted by an oxygen atom, and R ³ is 1 carbon atom.
~ 6 monovalent hydrocarbon groups, m is an integer of 1, 2 or 3. n represents an integer of 3 to 200. )

Specific examples of R ² include -CH ₂ -,-[CH ₂ CH (CH ₃ )]
-,-(CH ₂ ) ₃ -,-CH ₂ CH (CH ₃ ) CH ₂ -,-(CH ₂ ) ₆ -,-(CH ₂ ) ₁₂ -,-
(CH ₂ ) ₂ -O- (CH ₂ ) ₃ -,-(CH ₂ ) ₂ -O- (CH ₂ ) ₂ -O- (CH ₂ ) _3- and the like are exemplified, and specific examples of R ³ and R ⁴ are given. For example, -CH ₃ ,, CH ₂ CH ₃ , -CH
₂ CH ₂ CH ₃ , -CH ₂ CH ₂ CH ₂ CH _{3 and the} like are exemplified. n is 3 to 200
, Preferably an integer of 6 to 100. When n is less than 3, sufficient water repellency cannot be obtained, and when n exceeds 200, the film forming property of the coating composition using the resulting copolymer is poor and the durability of water repellency is poor.

In this silicone macromer, a (meth) acrylate-substituted chlorosilane compound represented by the following formula (4) and a terminal hydroxyl group-containing dimethylpolysiloxane compound represented by the following formula (5) are subjected to dehydrochlorination reaction according to a conventional method. Alternatively, it can be obtained by subjecting the compound represented by the above (4) and a dimethylpolysiloxane compound represented by the following formula (6) containing Li at the terminal to a dechlorination reaction according to a conventional method. . In addition, the side chain has Si-H
It can also be obtained by an addition reaction (in the presence of a Pt catalyst) of allyl (meth) acrylate with an organohydrogenpolysiloxane having one bond.

[0014]

[Chemical 7]

Specific examples of the silicone macromer represented by the general formula (1) include the following.

[Chemical 8]

[0016]

[Chemical 9]

The other radically polymerizable monomer copolymerized with the silicone macromer is preferably composed mainly of acrylate and / or methacrylate. Specific examples of acrylate and methacrylate include methyl (meth) acrylate, ethyl (meth) acrylate, and n-.
Alkyl (meth) acrylates such as butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-
Hydroxyalkyl (meth) acrylates such as hydroxypropyl (meth) acrylate and 2-hydroxybutyl (meth) acrylate; trifluoropropyl (meth) acrylate, perfluorobutylethyl (meth) acrylate, perfluorooctylethyl (meth) acrylate And fluorine-substituted alkyl (meth) acrylates; epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate and 3,4 epoxycyclohexylmethyl (meth) acrylate.

In the present invention, the main component being acrylate and / or methacrylate means that the total amount of the above-mentioned acrylate and / or methacrylate in the radical polymerizable monomer copolymerized with the silicone macromer is the radical polymerizable monomer. It means that it accounts for 50% by weight or more of the whole. This is because when the amount of acrylate and / or methacrylate is less than 50% by weight, the film forming property becomes insufficient and the durability of water repellency deteriorates.

Compounds other than the acrylate and / or methacrylate radical-polymerizable monomers copolymerized with the silicone macromer include (meth) acrylic acid; acrylamide; styrene; styrene derivatives; fumaric acid;
Maleic acid, derivatives thereof; acrylonitrile; vinylpyrrolidone; vinyl acetate; vinyl alkyl ethers; radical polymerizable macromers such as polyoxyalkylene and polycaprolactone having one radical polymerizable group in the molecule are exemplified. .

The copolymer used in the present invention, which is obtained by radically copolymerizing a silicone macromer and another radically polymerizable monomer copolymerizable with the silicone macromer, is further represented by the following general formulas (2) and (3). By using an alkoxysilane compound having a radically polymerizable group as a copolymerization component, durability and water repellency are further improved.

[Chemical 10] (X is a radically polymerizable group, R ² is a divalent hydrocarbon group having 1 to 12 carbon atoms which may be interrupted by an oxygen atom, R ⁵ and R ⁶ are each a monovalent hydrocarbon group having 1 to 4 carbon atoms, k represents an integer of 1 to 3.) Specific examples of the formulas (2) and (3) include radically polymerizable silanes which are exactly the same as those described above.

Including the case where the above-mentioned alkoxysilane compound having a radical-polymerizable group is copolymerized with the radical-polymerizable monomer mainly composed of silicone macromer and acrylate and / or methacrylate, the copolymerization ratio is 5 by weight. It is good to set it to -80 / 20-95 / 0-30, Preferably it is 10-50 / 30-85 / 5-20. When the silicone macromer is less than 5, sufficient water repellency cannot be obtained, and when it exceeds 80, the film-forming property is deteriorated and the durability of water repellency is deteriorated.
If the radical-polymerizable monomer mainly containing acrylate and / or methacrylate is less than 20, the film-forming property is deteriorated and the durability of water repellency is deteriorated, and if it exceeds 95, sufficient water repellency cannot be obtained. An alkoxysilane having a radically polymerizable group has an effect of improving the durability of water repellency, but even if it exceeds 30, not only can no further effect be expected, but also the stability of the copolymer is deteriorated. 30 or less.

With respect to 100 parts by weight of the acrylic resin solid matter, the compounding amount of the solid matter of the copolymer obtained by radical copolymerizing the silicone macromer and the radical polymerizable monomer copolymerizable with the silicone macromer is 10 ˜200 parts by weight, particularly preferably 20 to 100 parts by weight. When the amount of the latter compounded is less than 10 parts by weight, water repellency and weather resistance are poor, and
If it exceeds the weight part, the hardness of the coating film becomes low, which is economically disadvantageous.

Copolymerization is carried out by using organic peroxides such as benzoyl peroxide, dicumyl peroxide and lauroyl peroxide; 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobisiso. It is carried out in the presence of a usual radical polymerization initiator such as an azo compound such as butyronitrile, and any of the solution polymerization method and the bulk polymerization method can be applied. In this case, butyl mercaptan, dodecyl mercaptan, γ
Chain transfer agents such as -mercaptopropyltrimethoxysilane, carbon tetrachloride, α-methylstyrene dimer may also be used. In particular, the solution polymerization method is preferable because it is easy to adjust the molecular weight of the copolymer of the silicone macromer and the other radically polymerizable monomer 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, isopropanol, n
-Alcohols such as butanol and isobutanol, and the like, or a mixture of two or more kinds.

The polymerization temperature is preferably in the range of 50 to 180 ° C., particularly 60 to 120 ° C. Under this temperature condition, the polymerization reaction can be completed in about 5 to 10 hours.

The weight average molecular weight of the thus-produced copolymer obtained by radically copolymerizing the silicone macromer and another radical-polymerizable monomer copolymerizable with the silicone macromer, in terms of polystyrene by GPC, is It is preferably in the range of 5,000 to 500,000, particularly 10,000 to 100,000. If the weight average molecular weight is less than 5,000, the film-forming property becomes insufficient, resulting in poor water repellency, and if it exceeds 500,000, the compatibility with the acrylic resin becomes poor.

Further, a copolymer obtained by radically copolymerizing a silicone macromer and another radically polymerizable monomer copolymerizable with the silicone macromer can be compounded in an aqueous acrylic emulsion paint. The above copolymer is obtained by suspension polymerization of a silicone macromer and another copolymerizable monomer in an aqueous medium, or by emulsion-dispersing in an aqueous medium in the presence of a surfactant and then copolymerizing with a radical initiator. Is advantageous. In this way, it can be used in the state of being dispersed in water after the copolymerization. The blending amount of the obtained copolymer emulsion is 10 to 200 parts by weight based on 100 parts by weight of the resin solid component of the water-based acrylic emulsion paint.

A copolymer emulsion of a silicone macromer and another copolymerizable monomer is prepared by adding 0.1 to 10 parts by weight of a surfactant to 100 parts by weight of a mixture of the above-mentioned polymerizable monomer and silicone macromer, and then adding an aqueous medium. It is obtained by preparing an emulsion dispersion liquid therein, and subsequently performing emulsion polymerization using a water-soluble radical polymerization initiator. Known surfactants are used for preparing the emulsified dispersion liquid, and alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate, alkylnaphthalene sulfonates, polyoxyethylene alkyl allyl ether sulfonate monoester sodium are used. , Sodium lauryl sulfate, etc. are exemplified. As a water-soluble radical polymerization initiator used for emulsion polymerization, inorganic peroxides such as potassium persulfate, sodium persulfate and ammonium persulfate, t-
Butyl peroxymaleic acid, succinic acid peroxide,
organic peroxides such as t-butyl hydroperoxide,
2,2'-azobis [2- (N-benzylamidino) propane] hydrochloride, 2,2'-azobis [2- (N-2-
Hydroxyethylamidino) propane] hydrochloride, 2,
2'-azobis (2-methyl-N-hydroxyethyl)
Examples thereof include azobis compounds such as propionamide. Furthermore, acrylic acid or methacrylic acid is contained as a part of the other polymerizable monomer and neutralized with a tertiary amine such as triethanolamine to prepare an emulsion dispersion, followed by emulsification with a water-soluble radical polymerization initiator. A copolymer emulsion can also be obtained by polymerizing.

In preparing the copolymer emulsion, the silicone macromer and the radical-polymerizable monomer mainly containing acrylate and / or methacrylate are copolymerized with the alkoxysilane compound having the radical-polymerizable group. The polymerization ratio is 5 to 80 by weight.
/ 20-95 / 0-10, preferably 10-50 / 30
It is ~ 85 / 0-5. The mixing ratio of the silicone macromer and the radically polymerizable monomer mainly containing acrylate and / or methacrylate is the same as above, but if the mixing ratio of the alkoxysilane compound exceeds 10, gelation may occur during emulsion polymerization. It is not preferable.

If desired, the composition of the present invention may contain colorants, stabilizers, fats and oils, waxes, fillers and the like. Further, a curing catalyst of an alkoxysilyl group or silanol, such as an organic metal salt, a metal alkoxide, a metal chelate, an organic amine, a quaternary ammonium salt, etc., is added to the composition of the present invention within a range that does not impair its stability. However, the addition of these has the effect of promoting the hydrolysis, polycondensation and reaction with the inorganic surface of the composition in the pores of the object to be treated.

The weather resistant coating composition of the present invention comprises cement concrete, mortar, block, slate, brick,
It is applied to porous inorganic materials such as tiles, roof tiles and stones, and metal substrates such as iron plates and aluminum plates. Further, it is also useful as a top-coating paint for structures and undercoating of organic paints such as epoxy-based paints, acrylic-based paints, alkyd-based paints and the like. When the composition of the present invention is applied to these materials, it can be applied by brush coating, roller coating, flow coating, dip coating, or spray coating on the surface of the object to be treated. In this case, the coating amount is 1 to 1,000 g, more preferably about 10 to 200 g, per 1 m ^{2 of the} object to be treated.

[0032]

EXAMPLES Next, examples of the present invention will be described. In addition, the part in an example represents a weight part. Preparation Example 1 100 parts of xylene, 82 parts of methyl methacrylate, 11 parts of butyl acrylate, 7 parts of γ-methacryloxypropyltrimethoxysilane and azobisisobutyronitrile (AI
BN) 2 parts of the mixture was added dropwise under N ₂ aeration at 80 to 90 ° C. for 2 hours, and aged at 80 to 90 ° C. for 8 hours after the completion of the addition. The polystyrene reduced molecular weight was 45,000, the viscosity was 300 cS, and the nonvolatile content was
A 51% copolymer solution was obtained. This copolymer solution 100
White enamel A was prepared by adding 20 parts of titanium oxide and 0.5 part of dibutyltin dioctoate to the above parts and mixing with a ball mill.

Preparation Example 2 100 parts of toluene and 50 parts of methyl methacrylate,

[Chemical 11] A mixture of 30 parts, butyl methacrylate 12 parts, γ-methacryloxypropyltrimethoxysilane 8 parts and AIBN 2 parts was added dropwise under N ₂ aeration at 80 to 90 ° C for 2 hours, and after completion of the addition, aged at 80 to 90 ° C for 5 hours. Then, the polystyrene equivalent molecular weight
Copolymer solution B with 58,000, viscosity of 350 cS and non-volatile content of 51%-
Got 1.

Preparation Example 3 100 parts of toluene and 50 parts of methyl methacrylate,

[Chemical 12] A mixture of 30 parts, butyl methacrylate 20 parts and AIBN 2 parts was added dropwise under N ₂ aeration at 80 to 90 ° C for 2 hours, and after the addition was aged at 80 to 90 ° C for 5 hours, the polystyrene reduced molecular weight was 52,000 and the viscosity was 300 cS. A copolymer solution B-2 having a nonvolatile content of 50% was obtained.

Preparation Example 4 In a mixed solution of 69 parts of butyl methacrylate and 1 part of methacrylic acid

[Chemical 13] 30 parts was dissolved, and 2 parts of sodium lauryl sulfate and 50 parts of deionized water were added to the resulting mixed solution and emulsified and dispersed. In a separate flask, maintain a mixture of 70 parts deionized water and 10 parts 10% by weight aqueous ammonium persulfate solution at 80-85 ° C. under N ₂ aeration,
Emulsified dispersion of the above monomer mixture with stirring 150
Parts were added dropwise over 5 hours. 80 ~ 85 hours for 2 hours after the dropping
Aged at ℃, polystyrene equivalent molecular weight 200,000, nonvolatile content 42
% Copolymer emulsion B-3 was obtained.

Example 1 To 100 parts of white enamel A, 50 parts of copolymer solution B-1 was added and mixed well, and then polished on a mild steel plate (thickness: 0.3 mm) to give a dry film thickness of 30 μm.
After spray-coating so as to achieve the following, and drying for one week at room temperature, the coating film physical properties were measured, and the results are shown in Table 1.

Example 2 To 100 parts of white enamel A, 50 parts of copolymer solution B-2 was added and mixed well to prepare a test piece in the same manner as in Example 1. The coating film physical properties are shown in Table 1. did.

Example 3 80 parts of the copolymer emulsion B-3 was added to 100 parts of an aqueous acrylic paint [Emulsion white paint, non-volatile content 40%, manufactured by Atom Kagaku Paint Co., Ltd.] and mixed well, 1
A test piece was prepared in the same manner as in, and the physical properties of the coating film are shown in Table 1.

Comparative Example 1 A test piece was prepared in the same manner as in Example 1 using only white enamel A, and the coating film physical properties are shown in Table 1.

Comparative Example 2 A test piece was prepared in the same manner as in Example 1 using only the water-based acrylic paint (same as above), and the coating film had the first physical property.
It is noted in the table.

[0041]

[Table 1]

The viscosity in the above examples is the value measured at 25 ° C., and the physical property values in the examples are the values measured by the following methods. [Pencil hardness] Measured according to the pencil scratch test according to JIS K5400, item 6 and 14. [Cross-cut adhesion] In accordance with the cross-cut test of JIS K5400 Nos. 6 and 15, when 6 cuts are made with a cutter knife at intervals of 2 mm with a cutter knife, the cellophane tape is adhered to the coating film, and then peeled off with great force. I read the number of grids of the remaining paint film. [Water contact angle] Drop 5 μL of pure water on the test piece and apply Co.
It was measured using ntact Angle Meter CA-A [manufactured by Kyowa Kagaku Co., Ltd.]. [Water resistance] The appearance of the coating film after immersing the test piece in water for one week was visually judged. ◯: No abnormality △: Partially wet pattern X: Large wet pattern [Stain resistance] Mark on the cured coating with a black ink pen [Magic Ink manufactured by Pentel Co., Ltd.], air-dry for 10 minutes, and then isopropyl alcohol It was wiped with absorbent cotton impregnated with and visually determined according to the following criteria. ◯: No marking remained x: Marking remained [Accelerated weathering (QUV test)] Atlas Yubucon [trade name of Toyo Seiki Seisakusho Co., Ltd.] was used to irradiate ultraviolet rays, and the temperature was 70 ° C for 8 hours. Wet 50 ℃ x 4 hours cycle
After exposure for 1,000 hours, the gloss retention (%) and the contact angle of water (water repellency persistence) at that time were measured.

[0043]

INDUSTRIAL APPLICABILITY The composition of the present invention has a radical-polymerizable silicone macromer and another radical-polymerizable monomer copolymerizable with this macromer, which are radically added to an acrylic resin, particularly a hydrolyzable silyl group-containing acrylic resin. It is obtained by blending a copolymer formed by copolymerization, and this composition exhibits excellent properties as a weather resistant coating composition having improved water repellency, stain resistance and acid resistance. By adding an emulsion of a radical-polymerizable silicone macromer and a copolymer of a radical-polymerizable monomer copolymerizable with this macromer to an emulsion paint, stain resistance, stain-removing property and water repellency are imparted. The cured products of acrylic emulsion paints up to now tend to get water stains and smoke due to the influence of the surfactant.
Although it was difficult to remove, dimethylpolysiloxane can be fixed to the surface layer in the present invention, and the stain resistance is improved.
Moisture-curing (silane-crosslinking) acrylic paints have reduced gloss due to long-term UV irradiation, but a radical-polymerizable silicone macromer and a copolymer of this macromer with another radical-polymerizable monomer are blended and By curing, the gloss retention can be improved and the water repellency can be maintained for a long period of time.

Claims (4)

[Claims] 1. A radical of an organopolysiloxane compound having a structure of the following general formula (1) and another radical-polymerizable monomer copolymerizable with the organopolysiloxane to 100 parts by weight of the acrylic resin solid content. A weather-resistant coating composition, characterized in that a main resin component is obtained by mixing 10 to 200 parts by weight of a solid content of a copolymer obtained by polymerization. [Chemical 1] (R ¹ is hydrogen or a methyl group, R ² is a divalent hydrocarbon group having 1 to 12 carbon atoms which may be interrupted by an oxygen atom, R ³ is a monovalent hydrocarbon group having 1 to 6 carbon atoms, and m is 1 2 or 3 and n
Represents an integer of 3 to 200. ) 2. The weather resistant coating composition according to claim 1, wherein the acrylic resin contains two or more hydrolyzable silyl groups in one molecule. 3. The weather resistant coating composition according to claim 1, wherein the acrylic resin is a water-based acrylic emulsion. 4. A mixture of an organopolysiloxane compound of the general formula (1) and another radical-polymerizable monomer copolymerizable with the organopolysiloxane in an aqueous medium in the presence of a surfactant, to an aqueous acrylic emulsion. 4. The weather-resistant coating composition according to claim 1, which comprises a copolymer obtained by emulsion-dispersing and radical-polymerizing with a water-soluble radical polymerization initiator.