JPS6234275B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a coating composition with excellent surface hardness, abrasion resistance, flexibility, dyeability, and durability. Conventionally, it has often been done to improve the properties of articles, particularly their surface properties and appearance quality, by coating them. Many attempts have been made to make fragile items non-scratchable. Furthermore, it is equally important to provide a simple method of coloring to already scratch-resistant objects, such as inorganic materials such as glass, ceramics, metals, etc., without compromising their scratch-resistant properties. As an example of the former, many proposals have been made for plastic articles. For example, silicon-based coating materials (Japanese Patent Publication No. 50-28446, Japanese Patent Publication No. 51-2343, etc.) and silicon-based coating materials containing silica particles (Japanese Patent Publication No. 53-5042) have been proposed. They have insufficient flexibility and, more importantly, they lack sufficient dyeability. On the other hand, a coating material made of a composite obtained by reacting a vinyl polymer, particularly an acrylic copolymer, with water-dispersible silica has also been proposed. (Tokuko Showa 54
−22230). However, the durability of the films obtained from these is poor, and the stability of the paints is also insufficient. Furthermore, as a dyeable and highly hardened coating material, a cured product of silane hydrolyzate using an aluminum catalyst has been proposed (Japanese Patent Application Laid-Open No. 111336/1983), but it has the disadvantage of insufficient paint stability and is costly. Leads to increase. As another known example, it is known that silica is added as a filler to a paint made of a vinyl resin having a silyl group (Japanese Patent Laid-Open No. 54-36395
Publication No.). However, such known art paints lack stability at room temperature (pot life) and have practical problems. The present inventors have already proposed a dyeable coating composition that improves these points (Japanese Patent Application No. 1983-6839), but the coating composition described in detail below has further improved durability. It is something that has been obtained. A coating composition comprising the following components A, B and C, characterized in that the B component is 50 to 250 parts by weight per 100 parts by weight of the A component. A Vinyl polymer having a group represented by the general formula R ¹ _n (R ² O) _3-n Si. (Here, R ¹ is a methyl group or an ethyl group, R ² is an alkyl group, an alkoxyalkyl group, or an acyl group having 4 or less carbon atoms, and silicon is bonded to the polymer via a Si-C bond, m is 0,
1 or 2. ) B Fine particulate silica with an average particle diameter of about 1 to 200 mμ. C. Alcoholic solvent substantially free of water. The polymer used as component A in the present invention has a group represented by the above general formula in its molecule. Such polymers can be produced, for example, by (1) a method in which an unsaturated monomer having a group represented by the above general formula is copolymerized alone or with other vinyl monomers; (2) It can be produced by using a method such as reacting a vinyl polymer having a reactive functional group with a compound having a group represented by the above general formula. Here, examples of unsaturated monomers having a group represented by the general formula R ¹ _n (R ² O) _3-n Si- include γ-(meth)acryloxypropyltrimethoxysilane, γ-(meth) Acryloxypropyltriethoxysilane, γ-(meth)acryloxypropylmethyldimethoxysilane, γ-(meth)acryloxypropylethyldimethoxysilane, γ
-(meth)acryloxypropylmethyldiethoxysilane, γ-(meth)acryloxypropyldimethylmethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltriethoxyethoxysilane, glycidyl (meth)acrylate and γ−
Reaction products between aminopropyltrimethoxysilane, (meth)acrylic acid and γ-glycidoxypropyltrimethoxysilane, (meth)acrylic acid and γ-glycidoxypropylmethyldiethoxysilane Mention may be made of reaction products. In addition, the unsaturated monomer having a group represented by the above general formula R ¹ _n (R ² O) _3-n Si- can be polymerized alone and exhibits certain physical properties, but it has various practical performances. It is possible to copolymerize with other unsaturated monomers for expression. Here, it is necessary to contain the unsaturated monomer in an amount of 5% by weight or more, and if the amount is less than this, curing will not be sufficient. Unsaturated monomers that can be copolymerized with the unsaturated monomer having a group represented by the general formula R ¹ _n (R ² O) _3-n Si- include various monomers used in ordinary vinyl polymerization. are applicable, including alkyl esters of (meth)acrylic acid or halogenated alkyl esters, glycidyl (meth)acrylate, styrene,
γ-methylstyrene, vinyltoluene, (meth)
Examples include acrylamide, vinyl chloride, and vinyl acetate acrylonitrile. Furthermore, a monomer having a hydroxyl group and an unsaturated group increases the hydroxyl value (OH value) of the resulting copolymer.
It can be used in such amounts as to make it less than 150. Here, the hydroxyl value is the number of mg of caustic potassium equivalent to the hydroxyl group contained in 1 g of the polymer. Examples of these monomers include the formula (Here, R ³ is hydrogen or a methyl group, R ⁴ is an alkylene group having 4 or less carbon atoms, and n is an integer from 1 to 20.) Acetone acrylamide, N
Examples include -methylol acrylamide and (meth)acrylic acid 2-hydroxy-3-chloropropyl ester. However, acidic monomers such as (meth)acrylic acid are used so that the acid value of the copolymer (the number of mg of caustic potassium required to neutralize 1 g of polymer) is 20 or less, preferably 10 or less. If this value is exceeded, the stability of the polymer and the coating composition containing it decreases rapidly. When polymerizing an unsaturated monomer containing a group represented by the general formula R ¹ _n (R ² O) _3-n Si or a mixture of this and other monomers, known radical polymerization methods can be used. is used. Although various polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization can be applied to the polymerization, solution polymerization is preferred for the purpose of the present invention. The solvent used here is required to be a solvent that can dissolve or stably disperse the (co)polymer obtained from the above monomers, and for this reason, it is necessary to use an alcoholic solvent that does not substantially contain water. is necessary. Examples of alcoholic solvents include aliphatic, alicyclic, or aromatic alcohols having 2 or more carbon atoms, monoalkyl (poly)ethylene glycol, phenyl ethers, diacetone alcohol, and the like.
In the polymerization, compounds known as radical initiators, such as azo compounds and peroxides, are used as polymerization catalysts. In addition, various compounds known as chain transfer agents such as dodecyl mercaptan, butyl mercaptan, thioglycol, etc. can also be used to adjust the molecular weight of the (co)polymer. The molecular weight of the resulting copolymer varies depending on the purpose of use and copolymer composition, but the number average molecular weight is 2000.
~200,000, preferably 5,000 to 100,000 are used. Examples of vinyl polymers produced by the method (2) above include (meth)acrylic acid copolymer and γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane. or a reaction product with an epoxy group-containing silane such as β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, or a reaction product between a glycidoxy(meth)acrylate copolymer and an amino group-containing silane such as γ-aminopropyltrimethoxysilane. The reaction products can be mentioned. When such a method is used to introduce a group into a polymer by reacting a vinyl polymer with a compound having a group represented by the general formula R ¹ _n (R ² O) _3-n Si, it is also possible to introduce the group into the polymer. 5% by weight of an unsaturated monomer containing the group
It is necessary that the amount contained in the polymer is at least the same as that obtained from the copolymer. The fine particulate silica mentioned as component B has an average particle diameter of about 1 to 200 m.mu., with 5 to 100 m.mu. being particularly preferred.
Further, it is provided in the form of a powder or dispersed in a solvent, and in any case, it can be dispersed in the solvent in which the composition of the present invention is dissolved or dispersed. Here, the solvent used is one or a mixture of substantially water-free solvents including the same alcoholic solvents as mentioned above as the solvent for the copolymer of component A. Although moisture cannot be avoided, even trace amounts of moisture contained in the adsorbed water contained in the silica fine particles and moisture absorbed by the solvent are preferably kept at 5% or less in the total solvent. If the water content exceeds this amount, the stability of the paint will decrease. Particulate silica may also include silica that has been surface-treated, surface-coated, or modified for the purpose of improving dispersibility in solvents or resins. Mix A component and B component as described above,
In order to obtain the composition of the present invention, in addition to simple mixing, a method of copolymerizing the A component in the presence of the B component is used to produce the A component and the A component and the B component. It is also possible to perform the mixing operation at the same time. The mixing ratio of component A and component B is component B per 100 parts by weight of each coating film forming component other than component B, which includes component A as a solid content.
50 to 250 parts by weight, preferably 70 to 200 parts by weight are used. If the B component is more than this, cracks will occur in the coating film, and if it is less than this, a decrease in hardness and poor curability will occur. When applying this composition to an object to be coated, in addition to component A and component B, a catalyst that can be dispersed or dissolved in the solvent used may be added to accelerate curing. Furthermore, various solvents, additives, and resins can be added as necessary to improve coating workability and coating film properties. As the solvent or diluent, various solvents commonly known as paint solvents can be used, such as various alcohols, ethers, ketones, esters, aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons. However, as a solvent when applying the composition, at least
It is necessary to contain 10% by weight or more of an alcohol-based solvent. Various surfactants can be used as additives for the purpose of improving surface smoothness, and examples include silicone surfactants, fluorine surfactants, and organic surfactants. Other UV absorbers, antioxidants, matting agents, etc. can also be added. Furthermore, as a coating film improving agent, thermoplastic acrylic resins, polyester resins, epoxy resins, cellulose resins, etc. can be mentioned as organic polymers having good compatibility with the composition of the present invention, and are represented by the following general formula. Silicon compounds can be preferably used. R ⁵ _a R ⁶ _b Si(OR ⁷ ) _4-(a+b) (where R ⁵ and R ⁶ are alkyl having 1 to 10 carbon atoms,
Allyl, halogenated alkyl, alkenyl, or an organic group having an epoxy group, a (meth)acryloxy group, or a cyano group, which is bonded to silicon through a Si-C bond, and R ⁷ has 1 to 8 carbon atoms. is an alkyl group, an alkoxyalkyl group or an acyl group. a and b are 0, 1 or 2 and a+b is 0, 1 or 2). Examples of these compounds include tetraalkoxysilanes such as methyl silicate, ethyl silicate, n-propyl silicate, i-propyl silicate, n-butyl silicate, sec-butyl silicate and t-butyl silicate, methyltrimethoxysilane, methyl Triethoxysilane, methyltrimethoxyethoxysilane, methyltriacetoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane , phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, γ-chloropropyltriacetoxysilane, 3,3,3-tri Fluoropropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-(β-glycidoxyethoxy)propyltrimethoxysilane,
β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltriethoxysilane, γ-
methacryloxypropyltrimethoxysilane,
Trialkoxy or triacyloxysilanes such as β-cyanoethyltriethoxysilane, dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldiethoxysilane, phenylmethyldiethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, Sidoxypropylmethyldiethoxysilane, γ-glycidoxypropylphenyldimethoxysilane, γ
-glycidoxypropylphenyldiethoxysilane, γ-chloropropylmethyldiethoxysilane, dimethyldiacetoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-
Examples include dialkoxysilanes or diacyloxysilanes such as methacryloxypropylmethyldiethoxysilane, methylvinyldimethoxysilane, and methylvinyldiethoxysilane. Components other than component A and component B improve the water resistance, weather resistance, dyeability, adhesion, or chemical resistance of the coating formed from the composition of the present invention, depending on the application. The composition of the present invention can be applied to various substrates, and is used by coating it on the substrate. In this case, the objects to be coated include plastics, painted objects, etc., which have low scratch resistance as they are, and objects such as inorganic glass, ceramics, and metals, which have high inherent hardness but for which there is no easy method for coloring the surface. When applied to, the characteristics of the composition of the present invention can be exhibited. The composition of the present invention can be applied to the object by various methods commonly known in the industry, such as brush painting, dip painting, spin painting, flow painting, spray painting, roll painting, and curtain flow painting. A method can be used. When applying the composition of the present invention, various physical and
Chemical pretreatment or primer application can be performed. In particular, when applying to ceramic articles such as ceramics and glass, and metals, etc., it is preferable to use a silane coupling agent or a silane coupling agent with an acrylic resin, epoxy resin, urethane resin, amino resin, etc. applied thereto. be able to. The composition applied to the object as described above is cured by heating after application. The heating temperature varies depending on the applied substrate, curing time, and composition content, but is preferably 80 to 300°C, preferably 100 to 300°C.
250℃ applies. Various embodiments are possible for coloring the composition of the present invention, and coloring agents such as pigments and dyes can be included in the composition. staining is possible. As a dyeing method, dyeing with disperse dyes, acid dyes, basic dyes, anionic dyes, cationic dyes, and chelate-bound dyes can be carried out in a water-based solvent bath. Painting can also be carried out using a viscous dye paste prepared by mixing a substance, a surfactant, or a mixture thereof with water. Furthermore, a method is used in which a transfer paper impregnated with a sublimable disperse dye is attached and the pattern on the transfer paper is transferred and printed. At this time, dyeing can be made more robust by heating. In this dyeing, if a material that is more easily dyed is used as the base material for the coating made of the composition of the present invention, the dyeing becomes easier, but in this case, the coating made of the composition of the present invention is It has the effect of increasing the fastness of dyeing. Furthermore, the paint of the present invention can be applied using conventional techniques (for example, Japanese Patent Application Laid-Open No. 54
The most distinctive feature compared to the technology disclosed in Japanese Patent Publication No. 36395) is that the pot life can be extended to more than half a year, whereas the conventional technology had a pot life of about one week. The present invention will be explained in more detail with reference to Examples below. In all of the paints of the following examples, the moisture content in the solvent was less than 1%, and the pot life was more than half a year. Example 1, Comparative Example 1 (1) Synthesis of silane copolymerized acrylic varnish 128 g of n-propanol was charged into a four-necked flask equipped with a reflux device and a thermometer.
Heat to internal temperature of 90±2℃. Next, 30 g of methyl methacrylate, 56 g of ethyl acrylate, 14 g of 2-hydroxyethyl methacrylate, 35 g of methacryloxypropyltrimethoxysilane, and 1.35 g of n-dodecylmercaptan as a polymerization degree regulator.
Then, 1.35 g of azobisisobutyronitrile was added as a polymerization catalyst, dissolved uniformly, and added dropwise over about 2 hours while controlling the internal temperature to 90±2°C. Add 0.27 g each of azobisisobutyronitrile three times every 30 minutes after the completion of dripping, and add 1
Stirring was continued for a period of time to complete the polymerization. The viscosity of the produced varnish was 4.56 poise, the solid content concentration was 50.8%,
The hydroxyl value was 45 (per solid content). (2) Preparation of paint Silane copolymerized acrylic varnish 16 synthesized in (1)
g and 40 g of n-propanol silica sol (average particle size 13 mμ) having a solid content concentration of 30% by weight were thoroughly mixed, and 24 g of n-propanol was further added to make the paint solid content concentration 25%. (3) Application and evaluation of coating film The coating prepared in (2) was applied to substrates A and B by a dipping method to a dry film thickness of approximately 1.5 μm, and baked in a hot air dryer at 180° C. for 1 hour. The results of the coating film test are shown in Table 1 in comparison with commercially available baked-on acrylic paints for home appliances. Here, substrate A is a 1.5 mm thick glass plate (slide glass) coated with a silane coupling agent (0.5% methanol/n-propanol solution of hydrolyzate of γ-glycidoxypropyltrimethoxysilane). Coat and further apply acrylic (Kotatux SA105 (manufactured by Toray Industries, Inc.)) / melamine (Supervetsucomin G821 (product of Dainippon Ink Co., Ltd.)) / epoxy (Epicoat 1001 (product of Ciel Chemical Co., Ltd.)) = 70 / A thermosetting clear paint formulated with 30/10 (solid content weight ratio) and prepared with thinner to a solid content concentration of 22.5% was applied by dipping and heated at 160°C.
It was baked for 20 minutes to give a coating thickness of 5μ. Also, base material B is Bonderite #144 treated 0.8mm
Thick mild steel plate (product of Nippon Test Panel Co., Ltd.), acrylic (Kotax SA105 (product of Toray Industries, Inc.)) / melamine (Super Betsucomin G821 (product of Dainippon Ink Co., Ltd.)) / epoxy (Epicoat 1001)
(Ciel Chemical Co., Ltd. product) = Varnish with a solid content weight ratio of 70/20/10 and titanium white RCR-3 (ICI product)
Spray coated with a thermosetting white paint prepared at P/V=1/1 and baked at 160℃ for 20 minutes, resulting in a film thickness of approximately 25cm.
μ. The method for evaluating the performance of the coating film is shown below. B. Adhesion Cross-cut, Sellotape peel test. A completely good score is 100/100. B. Steel wool hardness (SW hardness) Rub the painted surface with #0000 steel wool to determine the degree of scratches. The criteria for evaluation are: A: No scratches. R: Slight scars are observed. C...Abrasion marks are left on the entire surface to the same extent as normal organic plastics. C Erichsen value The extrusion width in mm that does not cause cracks in the coating film is expressed using an Erichsen tester. (d) Impact resistance Using a Dupont impact tester, drop a 500g weight onto a 1/2 inch diameter weight and express the drop height in cm without causing any cracks in the coating. E. Boiling water resistance The painted piece is immersed in boiling water for a specified period of time.
Examine the appearance and adhesion of the paint film for cracks, blisters, etc. Judgment criteria are: 〇...No change at all. △...Slight deterioration in appearance or adhesion is observed. ×...The appearance has changed significantly and the adhesion has deteriorated. F Dyeability Disperse dye (mixture of red, yellow, and blue colors) bath at 90℃
Dye for 15 minutes and check the degree of staining. G Stain resistance Apply lipstick, magic red, blue, and black to the painted surface.
After leaving it at 23°C for 24 hours, wipe it off with gauze soaked in n-butanol and evaluate the degree of removal. Judgment criteria are: 〇...No traces remain. △...A little trace remains. ×……It leaves quite a trace.

【table】

[Table] Example 2 (1) Synthesis of silane copolymerized acrylic varnish In the same manner as in Example 1, n-propanol 250
30 g of methyl methacrylate, 56 g of ethyl acrylate, 14 g of 2-hydroxyethyl methacrylate, 200 g of methacryloxypropyltrimethoxysilane, and 3 g of n-dodecylmercaptan, and further dissolved 3 g of azobisisobutyronitrile. The solution was added dropwise to polymerize. The viscosity of the produced varnish was 4.30 poise, the solid content concentration was 53.0%, and the hydroxyl value was 20 (per solid content). (2) Preparation of paint The same procedure as in Example 1 was carried out. (3) Application and evaluation of coating film The coating was applied to substrates A and C and baked in the same manner as in Example 1, and the coating film was evaluated.
Here, the substrate C is a 1.5 mm thick glass plate (slide glass) coated with a silane coupling agent (0.5% methanol/n-propanol solution of hydrolyzate of glycidoxypropyltrimethoxysilane). . As for the evaluation results of the coating film, both substrates A and C had good coating appearance, good adhesion, steel wool hardness B, and good dyeability. Example 3 Synthesis of silane copolyacrylic varnish 128 g of n-propanol was prepared in the same manner as in Example 1.
was prepared as a polymerization solvent, and methyl methacrylate 43
g, ethyl acrylate 14.3g, butyl acrylate
28.7g, 2-hydroxyethyl methacrylate 14
g, methacryloxypropyltrimethoxysilane
35 g of n-dodecyl mercaptan were mixed, and a solution of 1.35 g of azobisisobutyronitrile was added dropwise for polymerization. The viscosity of the produced varnish was 4.55 poise, the solid content concentration was 51.0%, and the hydroxyl value was 44 (per solid content). Example 4 Synthesis of silane copolymerized acrylic varnish 128 g of n-propanol was prepared in the same manner as in Example 1.
was prepared as a polymerization solvent, and methyl methacrylate 30
g, ethyl acrylate 56g, methacrylic acid-2-
14 g of hydroxyethyl and 35 g of methacryloxypropyltrimethoxysilane were mixed, and 1.35 g of azobisisobutyronitrile dissolved therein was added dropwise for polymerization. The viscosity of the produced varnish was 6.0 poise, the solid content concentration was 51.5%, and the hydroxyl value was 45.5 (per solid content). Example 5, Comparative Example 2 A paint was prepared in the same manner as in Example 1 using the silane copolymer varnish synthesized in Examples 3 and 4, and applied to substrates A and B in the same manner as in Example 1. Baking was performed and the coating film was evaluated. The results are shown in Table 2 for comparison, along with those of thermosetting acrylic paint for home appliances.

[Table] From the above results, it can be seen that both the paints using the varnishes synthesized in Examples 3 and 4 showed remarkable improvement in coating film surface hardness, improvement in stain resistance, and imparting dyeability. Example 6 (1) Synthesis of silane copolymerized acrylic varnish In the same manner as in Example 1, n-propanol 128
40g of methyl methacrylate, 60g of ethyl acrylate, 35g of methacryloxypropyltrimethoxysilane, 1.35g of n-dodecylmercaptan, and further azobisisobutyronitrile.
A mixture of 1.35 g and a solution was added dropwise to polymerize. The viscosity of the produced varnish was 4.40 poise, and the solid content concentration was 50%. (2) Preparation of paint The same procedure as in Example 1 was carried out. (3) Application and evaluation of coating film As a result of coating and baking on base material A in the same manner as in Example 1 and evaluating the coating film, the appearance,
Good adhesion, steel wool hardness B to C, boiling water resistance after immersion for 3 hours, and dyeability were good. The material applied to the base material B had a steel wool hardness of B. Example 7 Using the silane copolymerized acrylic varnish synthesized in Example 1, the mixing ratio with n-propanol silica sol was adjusted according to the solid content weight ratio as shown in the table below, and the mixture was applied to base material A in the same manner as in Example 1. Coating, baking, and evaluation were performed. The results are also shown in the table. The results show that the mixing ratios described in the specification are good.

[Table] Example 8 1.6 g of glycidoxypropylmethyldiethoxysilane was further added to the paint prepared in Example 1 (2) and mixed uniformly, and the mixture was applied to base material A in the same manner as in Example 1. As a result of evaluating the baked coating film, it was found that the coating film had good appearance, adhesion, steel wool hardness B, and dyeability.

Claims (1)

[Scope of Claims] 1 Consisting of the following components A, B and C, and A
A coating composition characterized in that component B is contained in an amount of 50 to 250 parts by weight based on 100 parts by weight of the component. A Vinyl polymer having a group represented by the general formula R ¹ _n (R ² O) _3-n Si-. (Here, R ¹ is a methyl group or an ethyl group, R ² is an alkyl group, an alkoxyalkyl group, or an acyl group having 4 or less carbon atoms, and silicon is bonded to the polymer via a Si-C bond, m is 0,
1 or 2. ) B Fine particulate silica with an average particle diameter of about 1 to 200 mμ. C. Alcoholic solvent substantially free of water. 2. The coating composition according to claim 1, wherein the water content of the alcoholic solvent as component C is 5% by weight or less based on the total solvent. 3. The coating composition according to claim 1, wherein the vinyl polymer as component A contains 5% by weight or more of an unsaturated monomer.