JP3242442B2 - Composition for coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition, and more particularly, to a steel plate or a non-ferrous metal such as aluminum or stainless steel, an inorganic building material such as concrete or slate, or a surface of a plastic substrate or the like. The present invention relates to a coating composition that can be cured by being left at room temperature or being subjected to heat treatment at a low temperature, has high hardness, and can form a film having excellent heat resistance and weather resistance.

[0002]

2. Description of the Related Art Conventionally, as a coating agent capable of forming a durable coating for the purpose of protecting the surface of a steel plate or a non-ferrous metal such as aluminum or stainless steel, an inorganic building material such as concrete or slate, or a plastic substrate, etc. A coating agent obtained by hydrolyzing or partially hydrolyzing a degradable organosilane, or a coating agent obtained by mixing colloidal silica with the coating composition is known.

[0003] For example, JP-A-51-2736,
JP-A-51-2737, JP-A-53-13073
No. 2, JP-A-63-168470 discloses an organoalkoxysilane, a hydrolysis and / or a partial condensate of the organoalkoxysilane and colloidal silica, and the alkoxy group is converted to silanol with excess water. A coating agent has been proposed.
The films obtained with these coating agents have high hardness, good weather resistance and are excellent for protecting substrates.

[0004] However, the coating agents proposed in the above-mentioned publications require about 1 to obtain required film properties.
Baking by a heat treatment at a high temperature of 00 ° C. or more or for a long time was necessary, and there was an inconvenience that the method could not be applied depending on the molding method and dimensions of the substrate, heat resistance, or places such as outdoors. In addition, these coating compositions have a problem in that the activity of silanol obtained by hydrolysis of alkoxysilane is high, and their condensation reaction occurs gradually even at ordinary temperature to easily cause gelation, resulting in poor stability. In particular, when these coating compositions are used as a vehicle and a pigment is added to form a paint, stability is further deteriorated, and there is a drawback that a paint cannot be formed.

In Japanese Patent Application Laid-Open No. 64-168, a coating agent for converting an alkoxy group into silanol by adding water and a catalyst, called a curing agent, to a partial hydrolysis or partial condensate of an alkoxysilane immediately before coating is disclosed. Proposed. The coating agent obtained in this way has good storage stability,
Although it is relatively stable even if it is made into a paint by adding a pigment, baking by a high temperature of about 100 ° C. or more or a long-time heat treatment is necessary to obtain the required film properties. Not applicable depending on places such as heat resistance or outdoors.

For the purpose of overcoming such disadvantages, Japanese Patent Application Laid-Open No. 63-268772 proposes a coating agent comprising a prepolymer mainly composed of silicon alkoxide, a curing catalyst and water, which is cured at around room temperature. . On the other hand, silicone resins are known as vehicles for heat-resistant paints or weather-resistant paints. Many of these are composed of silanol group-containing polysiloxanes.In general, such silanol group-containing organopolysiloxanes often hydrolyze organochlorosilanes into a toluene or xylene solution, and use organoalkoxysilanes. Even though the hydrolyzate is dissolved in toluene or xylene, the silanol group is subjected to a condensation reaction. The thus obtained silicone resin solution has a good stability even when a pigment is kneaded into the paint.

[0007]

The above-mentioned coating agent which cures at around room temperature has drawbacks such as poor coatability, poor curing characteristics of the coating agent, and susceptibility of the curing characteristics of the coating agent to humidity. Coatings using the above silicone resin solution have the disadvantage that they must be treated at a high temperature for a long time to form a heat-cured coating, and there is a limit to increasing the coating hardness even after a long heating treatment. This is an insufficient property as a durable film.

According to the present invention, it is possible to cure and dry at room temperature at the same time as the curing by accelerated heating at a relatively low temperature, and to form a film having high hardness and excellent heat resistance. It is an object to provide a good coating composition.

[0009]

Means for Solving the Problems As a result of intensive studies on the solution of the above problems, the inventors have found that a silica-dispersed oligomer obtained by partially hydrolyzing alkoxysilane in colloidal silica dispersed in a solvent or water and a silanol group The present inventors have found that a coating composition comprising an organopolysiloxane and a catalyst exhibits excellent performance, and have completed the present invention.

That is, the present invention relates to (A) a compound represented by the general formula (I): R ¹ _n SiX _4-n (I) wherein R ¹ is the same or different alkyl group, cycloalkyl
Alkyl group, alkenyl group, halogen-substituted hydrocarbon group,
γ-methacryloxypropyl group, γ-glycidoxypro
Pill group, 3,4-epoxycyclohexylethyl group and
And selected from the group consisting of γ-mercaptopropyl groups,
A monovalent hydrocarbon group having 1 to 8 carbon atoms, n is an integer of 0 to 3, X is an alkoxy group, an acetoxy group, an oxime group,
From nonoxy, amino, aminoxy and amide groups
And a hydrolyzable group selected from the group consisting of In colloidal silica in which a hydrolyzable organosilane (also referred to as a hydrolyzable group-containing organosilane) represented by the following formula (1) is dispersed in an organic solvent or water:
It is partially hydrolyzed under conditions using 0.5 mol,
An organosilane silica-dispersed oligomer solution, (B) average composition formula (II) R ² _a Si (OH) _b O _{(4-ab) / 2} ... (II) (where R ² is the same or different alkyl, Group, cyclo
Alkyl group, alkenyl group, halogen-substituted hydrocarbon group,
γ-methacryloxypropyl group, γ-glycidoxypro
Pill group, 3,4-epoxycyclohexylethyl group and
And selected from the group consisting of γ-mercaptopropyl groups,
Represents a monovalent hydrocarbon group having 1 to 8 carbon atoms, wherein a and b are 0.2 ≦ a ≦ 2, 0.0001 ≦ b ≦ 3, and a + b, respectively.
It is a number that satisfies the relationship of <4. A) a polyorganosiloxane containing 1 to 30 mol% of a phenyl group in R ² of the component relative to all R ² groups, and (C) condensation of the components (A) and (B) The catalyst which promotes the reaction is an essential component, and the component (A) contains 5-95% by weight of silica as a solid content, and at least 50 mol% of the hydrolyzable organosilane is n = 1 organosilane. ,
Component (B) 99-1 based on 1-99 parts by weight of component (A)
Provide a coating composition in which parts by weight are blended.

The silica-dispersed oligomer of the component (A) used in the present invention is a main component of a base polymer having a hydrolyzable group as a functional group which participates in a curing reaction when forming a film. This is accomplished by adding one or more of hydrolyzable group-containing organosilanes represented by the general formula (I) to colloidal silica dispersed in an organic solvent or water,
With water in colloidal silica or water added separately,
It is obtained by partially hydrolyzing the hydrolyzable organosilane.

The group R ¹ in the hydrolyzable organosilane represented by the general formula (I) is an alkyl group, a cycloalkyl
Group, alkenyl group, halogen-substituted hydrocarbon group, γ-meta
Acryloxypropyl group, γ-glycidoxypropyl group,
3,4-epoxycyclohexylethyl group and γ-meth
1 carbon atom selected from the group consisting of a rucaptopropyl group
And represents an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group and an octyl group; and a cycloalkyl group such as a cyclopentyl group and a cyclohexyl group. Aralkyl groups such as 2-phenylethyl group and 3-phenylpropyl group; aryl groups such as phenyl group and tolyl group; alkenyl groups such as vinyl group and allyl group; chloromethyl group, γ-chloropropyl group; Halogen-substituted hydrocarbon groups such as 3,3,3-trifluoropropyl group and γ-methacryloxypropyl group, γ-glycidoxypropyl group, 3,4-epoxycyclohexylethyl group, γ
And substituted hydrocarbon groups such as -mercaptopropyl group. Among these, an alkyl group having 1 to 4 carbon atoms and a phenyl group are preferable in terms of ease of synthesis or availability.

X of the hydrolyzable group is a hydrolyzable group selected from the group consisting of an alkoxy group, an acetoxy group, an oxime group, an enoxy group, an amino group, an aminoxy group and an amide group.
It is . An alkoxy group is preferred because of its availability and ease of preparing a silica-dispersed oligomer solution.

Particularly, tetramethoxysilane, tetraethoxysilane and the like can be exemplified as n = 0 tetraalkoxysilane, and methyltrimethoxysilane, methyltriethoxysilane, methyltriisosilane can be exemplified as organotrialkoxysilane with n = 1. Propoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane,
3,3,3-trifluoropropyltrimethoxysilane can be exemplified. Examples of the diorganodialkoxysilane having n = 2 include dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and methylphenyldimethoxysilane, and the like. Examples thereof include trimethylmethoxysilane, trimethylethoxysilane, trimethylisopropoxysilane, and dimethylisobutylmethoxysilane. Further, an organosilane compound generally called a silane coupling agent is also included in the alkoxysilanes.

It is necessary that at least 50 mol% of the hydrolyzable organosilane represented by the general formula (I) is a trifunctional one represented by n = 1. They are more preferably at least 60 mol%, most preferably at least 70 mol%. If the content is less than 50 mol%, sufficient coating film hardness cannot be obtained, and dry curability tends to be poor.

The colloidal silica in the component (A) is essential for increasing the hardness of the cured film of the coating composition of the present invention. As such colloidal silica, water-dispersible or non-aqueous organic solvent-dispersible colloidal silica such as alcohol can be used. Generally, such colloidal silica has a silica content of 20%.
-50% by weight, and the silica content can be determined from this value. When water-dispersible colloidal silica is used, water present as a component other than the solid content can be used for hydrolysis of the organosilicon compound as the component (A). These are usually made from water glass, but such colloidal silica is readily available commercially. The organic solvent-dispersed colloidal silica can be easily prepared by replacing water of the water-dispersible colloidal silica with an organic solvent. Such an organic solvent-dispersed colloidal silica can be easily obtained as a commercial product similarly to the water-dispersed colloidal silica. The type of the organic solvent in which the colloidal silica is dispersed includes, for example, lower aliphatic alcohols such as methanol, ethanol, isopropanol, n-butanol, and isobutanol; ethylene glycol, ethylene glycol monobutyl ether, and ethylene glycol monoethyl acetate; And ethylene glycol derivatives; diethylene glycol derivatives such as diethylene glycol and diethylene glycol monobutyl ether; and diacetone alcohol. One or more selected from the group consisting of these can be used. In combination with these hydrophilic organic solvents, toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methyl ethyl ketoxime and the like can also be used.

In the component (A), colloidal silica is contained in a range of 5 to 95% by weight as a silica component. More preferably from 10 to 90% by weight, most preferably from 20 to 90% by weight.
It is in the range of 85% by weight. If the content is less than 5% by weight, the desired coating hardness cannot be obtained, and if it exceeds 95% by weight, it becomes difficult to uniformly disperse the silica, and the component (A) may cause inconvenience such as gelation. .

The silica-dispersed oligomer of component (A) can be usually obtained by partially hydrolyzing a hydrolyzable group-containing organosilane in water-dispersed colloidal silica or organic solvent-dispersed colloidal silica. The amount of water used with respect to the hydrolyzable organosilane is preferably 0.001 to 0.5 mol per 1 mol of the hydrolyzable group (X). If the ratio is less than 0.001 mol, a sufficient partial hydrolyzate cannot be obtained, and if it exceeds 0.5 mol, the stability of the partial hydrolyzate deteriorates. The method for performing the partial hydrolysis is not particularly limited, and the hydrolyzable organoalkoxysilane and colloidal silica may be mixed and a necessary amount of water may be added and blended. At this time, the partial hydrolysis reaction proceeds at room temperature. You may heat to 60-100 degreeC in order to accelerate a partial hydrolysis reaction.
In order to further promote the partial hydrolysis reaction, hydrochloric acid, acetic acid, halogenated silane, chloroacetic acid, citric acid, benzoic acid, dimethylmalonic acid, formic acid, propionic acid, glutaric acid, glycolic acid, maleic acid, malonic acid, toluene Organic acids such as sulfonic acid and oxalic acid and inorganic acids may be used as the catalyst.

The component (A) must have a pH of 2.0 to 7.0, preferably 2.
It is good to be 5-6.5, more preferably 3.0-6.0. When the pH is out of this range, the long-term performance of the component (A) is remarkably reduced particularly when the amount of water used is 0.3 mol or more per 1 mol of the group (X). When the pH of the component (A) is out of this range, it may be adjusted by adding a basic reagent such as ammonia or ethylenediamine as long as it is more acidic than this range. And an acidic reagent such as acetic acid. However, the adjustment method is not particularly limited.

Component (B), a silanol group-containing polyorganosiloxane, is an important component that characterizes the present invention.
Such component (B) in the average composition formula ^{_{R 2 a Si (OH) b}} O (4-ab) / 2 ... (II) ( wherein, R ² is identical or different, an alkyl group, a cycloalkyl
Alkyl group, alkenyl group, halogen-substituted hydrocarbon group,
γ-methacryloxypropyl group, γ-glycidoxypro
Pill group, 3,4-epoxycyclohexylethyl group and
And selected from the group consisting of γ-mercaptopropyl groups,
Represents a monovalent hydrocarbon group having 1 to 8 carbon atoms, wherein a and b are 0.2 ≦ a ≦ 2, 0.0001 ≦ b ≦ 3, and a + b, respectively.
It is a number that satisfies the relationship of <4. ).
In the formula, R ² below the phenyl group is the same as R ² in the above (I).
^{Although the} same as ¹ is exemplified, preferably, it has 1 to 1 carbon atoms.
And a substituted hydrocarbon group such as an alkyl group, a vinyl group, a γ-glycidoxypropyl group, a γ-methacryloxypropyl group, and a 3,3,3-trifluoropropyl group, and more preferably a methyl group. Further, in the formula, a and b are numbers satisfying the above relationship, and a is less than 0.2 or b
Exceeds 3, there are disadvantages such as cracks in the cured film, and when a is more than 2 and 4 or less, or when b is less than 0.0001, curing does not proceed well.

Further, when R ² contains 1 to 30 mol%, preferably 5 to 20 mol% of phenyl groups based on all R ² groups, a coating film having excellent gloss and leveling properties can be obtained. If the phenyl group content is less than 1 mol% based on all R ² groups, the desired gloss cannot be obtained, and if it is more than 30 mol%, the gloss is reduced and the coating film becomes soft.

Such a silanol group-containing polyorganosiloxane can be prepared by a known method using methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, or a mixture of two or more alkoxysilanes corresponding thereto. Can be obtained by hydrolysis with a large amount of water. When a silanol group-containing polyorganosiloxane is hydrolyzed by a known method using alkoxysilane, a small amount of an unhydrolyzed alkoxy group may remain. That is, a polyorganosiloxane in which a silanol group and a trace amount of an alkoxy group coexist may be obtained, but in the present invention, such a polyorganosiloxane may be used.

The curing catalyst which is the component (C) of the present invention promotes the condensation reaction between the components (A) and (B) as described above, and cures the coating. Examples of such a catalyst include metal salts of carboxylic acids such as alkyl titanates, tin octylate and dibutyltin dilaurate and dioctyltin dimaleate; amine salts such as dibutylamine-2-hexoate, dimethylamine acetate, and ethanolamine acetate; Carboxylic acid quaternary ammonium salts such as tetramethylammonium acetate; amines such as tetraethylpentamine; N-β-aminoethyl-γ-
Amine silane coupling agents such as aminopropyltrimethoxysilane and N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane; acids such as p-toluenesulfonic acid, phthalic acid and hydrochloric acid; aluminum alkoxides and aluminum chelates Alkaline catalysts such as aluminum compounds and potassium hydroxide; titanium compounds such as tetraisopropyl titanate, tetrabutyl titanate and titanium tetraacetylacetonate; halogenated silanes such as methyltrichlorosilane, dimethyldichlorosilane and trimethylmonochlorosilane;
There is no particular limitation as long as it is effective for the condensation reaction with the components (A) and (B) in addition to the catalyst.

The mixing ratio of the component (A) and the component (B) is such that the component (B) 99
To 1 part by weight, more preferably the component (A) is 5 to 95 parts by weight.
95 to 5 parts by weight of component (B), most preferably 10 to 90 parts by weight of component (A)
0 to 10 parts by weight (however, the total of the components (A) and (B) is 100 parts by weight). If the component (A) is less than 1 part by weight, the curability at room temperature is inferior, and sufficient coating hardness cannot be obtained. On the other hand, if it exceeds 99 parts by weight, the curability is unstable and a good coating film is obtained. There may not be.

The amount of the component (C) added is 0.0001 with respect to 100 parts by weight of the total of the components (A) and (B).
It is preferably from 10 to 10 parts by weight. It is more preferably 0.0005 to 8 parts by weight, most preferably 0.05 to 8 parts by weight.
007 to 5 parts by weight. If it is less than 0.0001 parts by weight, it will not cure at room temperature. If it exceeds 10 parts by weight, heat resistance and weather resistance deteriorate.

The coating composition of the present invention can be used after being diluted with various organic solvents for ease of handling. The type of the organic solvent can be selected depending on the type or molecular weight of the monovalent hydrocarbon group of the component (A) or the component (B). Examples of such organic solvents include lower aliphatic alcohols such as methanol, ethanol, isopropanol, n-butanol, and isobutanol, which are shown as dispersion solvents for colloidal silica; ethylene glycol, ethylene glycol monobutyl ether, and ethylene glycol monoethyl acetate. Ethylene glycol derivatives such as ethers; diethylene glycol derivatives such as diethylene glycol and diethylene glycol monobutyl ether; and diacetone alcohol; and one or more selected from the group consisting of these can be used. . Examples of solvents that can be used in combination with these hydrophilic organic solvents include toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, and methyl ethyl ketoxime.

As a method for storing the coating composition of the present invention, it is general to take a three-package form for storing the components (A), (B) and (C), respectively. Separate the mixed component of the component (C) and the component (B) into two packages, and mix them both at the time of use, or mix all the components and store them in one container in a single package. It is possible. However, when the component (A) and the component (C) are mixed and stored, it is preferable to add the component (C) after adjusting the pH of the component (A) to 2 to 7, and further to add the component (A).
Hydrolyzable group (X) of organoalkoxysilane of component
The amount of water used per mole is preferably 0.3 mol or less.

The coating composition of the present invention is made of plastics such as polycarbonate resin, acrylic resin and ABS resin, metals such as aluminum, stainless steel, copper, iron and duralumin, or paper, wood, glass, cement and gypsum. It can also be applied to the surface protection of wall materials and the like, as well as acrylic, alkyd, polyester, epoxy and urethane paints.

The thickness of the coating is not particularly limited.
The thickness is preferably from 1 to 100 μm, but is preferably from 1 to 80 μm in order to stabilize the adhesion of the coating film over a long period of time and prevent cracks and peeling. The coating composition of the present invention can be coated by a usual coating method, and various coating methods such as brushing, spraying, dipping, flow, roll, curtain, and knife coating can be selected. The dilution ratio in the organic solvent is not particularly limited, and the dilution ratio may be determined as needed.

The coating composition of the present invention may contain a leveling agent, a thickener, a pigment, a dye,
Aluminum paste, glass frit, metal powder, antioxidant,
An ultraviolet absorber or the like can be added within a range that does not affect the present invention.

[0031]

The hydrolyzable group contained in the silica-dispersed oligomer of the component (A) and the silanol group of the component (B) are:
In the presence of the curing catalyst of the component (C), a condensation reaction is caused by heating at room temperature or at a low temperature to form a cured film. Therefore, like a moisture-curing type coating composition,
The coating composition of the present invention is hardly affected by humidity even when cured at room temperature. In addition, a heat treatment can promote a condensation reaction to form a cured film.

[0032]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to specific examples and comparative examples, but the present invention is not limited to the following examples. Unless otherwise specified in the examples, all “parts” represent “parts by weight” and all “%” represent “% by weight”. First, an example of a method for preparing the component (A) will be described. (Preparation Example A-1) A methanol-dispersed colloidal silica sol MA-ST (particle diameter: 10 to 20 m) was placed in a flask equipped with a stirrer, a heating jacket, a condenser, and a thermometer.
μ, solid content 30%, manufactured by Nissan Chemical Industries, Ltd.) 100 parts, methyltrimethoxysilane 68 parts, and water 10.8 parts are charged, and the partial hydrolysis reaction is carried out at 65 ° C. for about 5 hours while stirring. The mixture was cooled to obtain the component (A). This one is
The solid content when left at room temperature for 48 hours was 36%. The component (A) obtained here is referred to as A-1. The conditions for preparing A-1 were as follows. Number of moles of water per mole of hydrolyzable group: 4 × 10 ^−1. Silica content of component (A): 47.3%. Mole% of n = 1 hydrolyzable organosilane: 100
(Preparation Example A-2) n-Butanol colloidal silica sol: NBA-ST (particle size: 10 to 2) in a flask equipped with a stirrer, a heating jacket, a condenser, and a thermometer.
0 mμ, solid content 20%, manufactured by Nissan Chemical Industries) 150 parts,
178 parts of methyltriethoxysilane, 21.4 parts of 3,3,3-trifluoropropyltrimethoxysilane, 12 parts of dimethyldimethoxysilane, 26 parts of water, 0.1 part of acetic anhydride.
Two parts were charged and a partial hydrolysis reaction was carried out at a temperature of 80 ° C. for about 8 hours while stirring, followed by cooling to obtain the component (A). This had a solid content of 31% when left at room temperature for 48 hours. The component (A) obtained here is referred to as A-2. The conditions for preparing A-2 were as follows. The number of moles of water per mole of the hydrolyzable group: 4 × 10 ^−1. The silica content of the component (A): 25.2%. The mole% of the n = 1 hydrolyzable organosilane: 92 mole%. (Preparation Example A-3) 100 parts of methyltris (methylethylketoxime) silane in a flask equipped with a stirrer, a heating jacket, a condenser and a thermometer, and then n-butanol silica sol NBA-ST (particle size: 10 to 10%)
A mixture of 100 parts (20 μm, solid content 20%, manufactured by Nissan Chemical Industries, Ltd.) and 9 parts of water was added with stirring, and a partial hydrolysis reaction was carried out at room temperature for about 8 hours, followed by cooling to obtain the component (A). This had a solid content of 31% when left at room temperature for 48 hours. The component (A) obtained here is referred to as A-3. The conditions for preparing A-3 were as follows. The number of moles of water per mole of the hydrolyzable group: 5 × 10 ^−1. The silica content of the component (A): 47.3%. The mole% of the n = 1 hydrolyzable organosilane: 100
(Preparation Example A-4) In a flask equipped with a stirrer, a heating jacket, a condenser and a thermometer, xylene n was added.
-Butanol-dispersed colloidal silica sol XBA-ST
(Particle size 10-20 μm, solid content 30%, H ₂ O 0.2
%, Manufactured by Nissan Chemical Industries, Ltd.) and 68 parts of methyltrimethoxysilane, and a partial hydrolysis reaction was carried out at a temperature of 65 ° C. for about 5 hours with stirring, followed by cooling to obtain the component (A). . This had a solid content of 36% when left at room temperature for 48 hours. The component (A) obtained here is represented by A-
No. 4. The conditions for preparing A-4 were as follows. Number of moles of water per mole of hydrolyzable group: 7 × 10 ^−3. Silica content of component (A): 47.2%. Mole% of n = 1 hydrolyzable organosilane: 100
(Preparation Example A-5) In a flask equipped with a stirrer, a heating jacket, a condenser, and a thermometer, isopropyl alcohol-dispersed colloidal silica sol IPA-ST (particle diameter: 10 to 20 mμ, solid content: 30%, H ₂ O.O. 5%,
100 parts, Nissan Chemical Industry Co., Ltd.) 100 parts, methyltrimethoxysilane 68 parts, dimethyldimethoxysilane 18 parts, water 2.7
And 0.1 part of acetic anhydride, and stirring
The partial hydrolysis reaction was performed at a temperature of about 3 hours for about 3 hours, and the mixture was cooled to obtain the component (A). This had a solid content of 36% when left at room temperature for 48 hours. The component (A) obtained here is referred to as A-5. The preparation conditions for A-5 were as follows. The number of moles of water based on 1 mole of the hydrolyzable group: 1 × 10 ^−1. The silica content of the component (A): 40.2%. The mole% of the n = 1 hydrolyzable organosilane: 77 mole%. (Preparation Example A-6) In a flask equipped with a stirrer, a heating jacket, a condenser, and a thermometer, isopropyl alcohol-dispersed colloidal silica sol IPA-ST (particle diameter: 10 to 20 mμ, solid content: 30%, H ₂ O: 0.5%) ,
Nissan Chemical Industries, Ltd.) 100 parts, methyltrimethoxysilane 68 parts, trimethylmethoxysilane 5 parts, water 2.3
And 0.1 part of acetic anhydride, and the mixture was subjected to a partial hydrolysis reaction at a temperature of 80 ° C. for about 3 hours while stirring, followed by cooling to obtain a component (A). This had a solid content of 36% when left at room temperature for 48 hours. The component (A) obtained here is referred to as A-6. The conditions for preparing A-6 were as follows. Number of moles of water per mole of hydrolyzable group: 1 × 10 ^−1. Silica content of component (A): 44.5%. Mole% of hydrolyzable organosilane with n = 1: 91.
Next, an example of a method for preparing the component (B) will be described. (Preparation Example B-1) A mixed solution of 220 parts (1 mol) of methyltriisopropoxysilane and 150 parts of toluene was weighed and placed in a flask equipped with a stirrer, a heating jacket, a condenser, a dropping funnel, and a thermometer. Hydrochloric acid aqueous solution 1
08 parts was added dropwise to the above mixture in 20 minutes to hydrolyze methyltriisopropoxysilane. After 40 minutes, the stirring was stopped, and the lower layer of water containing a small amount of hydrochloric acid separated into two layers
The mixed solution of isopropyl alcohol is separated, the hydrochloric acid in the remaining toluene resin solution is removed by washing with water, the toluene is further removed under reduced pressure, and the residue is diluted with isopropyl alcohol and silanol-containing organopolysiloxane having an average molecular weight of about 2,000. Of isopropyl alcohol was obtained. This is called B-1. The molecular weight was measured by GPC (gel permeation chromatography) using a calibration model name HLC-802UR (manufactured by Tosoh Corporation) to create a calibration curve with standard polystyrene. The subsequent molecular weight was measured in the same manner.

Preparation conditions for B-1: mol% of phenyl group = (mol number of phenyl group / mol number of all non-hydrolyzable groups R ² ) × 100 0% (Preparation Examples B-2 to B-) 5) Preparation Example B-1 except that a part of methyltriisopropoxysilane was changed to the hydrolyzable organosilane shown in Table 1, water and acetone were used instead of a 1% hydrochloric acid aqueous solution, and a toluene solution was further used. In the same manner as in the above, toluene solutions B-2 to B-5 of the silanol group-containing organopolysiloxane were obtained.

Table 1 also shows the number of moles of the phenyl group, the average molecular weight, and the concentration of the polyorganosiloxane.

[0035]

[Table 1]

Examples 1 to 8 The components shown in Tables 2 and 3 were mixed in the proportions shown in the same table to obtain the coating composition of the present invention. This was spray-coated on a test piece (Alstar: trade name of Nippon Test Panel Co., Ltd.), which was sprayed with aluminum, and the coating thickness was about 10 μm.
And cured at a curing temperature of 140 ° C. for 30 minutes to form a coating (coating) and a curing temperature of 80
The film was cured at 30 ° C. for 30 minutes to form a coating film (coating film), and the coating film characteristics (coating film characteristics) were tested.

The coating property test was based on the following evaluation method. Adhesion: The adhesion to the substrate was examined by a cross-cut cellophane adhesive tape (cellotape) peel test, and the number of cross-cuts remaining on the substrate out of 100 cross-cuts was shown. -Coating hardness: Pencil hardness test method (according to JIS K5400)-Solvent resistance: The coating film is slightly pressed with gauze containing toluene and rubbed 100 times reciprocally, and the state of the coating film at that time is observed. Those having no change were regarded as having good curability. -Boiling resistance: After boiled in tap water and tested for 16 hours, the test piece was allowed to stand for 1 hour and the state of the coating film was observed.・ Weather resistance: Sunshine weatherometer (JIS K
According to 5400. ) And irradiation for 2500 hours, the state of the coating film was observed. Gloss: Specular gloss measurement method (according to JIS K5400) 60 of color difference meter (Z- # 80 manufactured by Nippon Denshoku Industries Co., Ltd.)
Degree specular gloss.

Comparative Examples 1 to 4 Coating films were prepared in the same manner as in the examples, with the formulations shown in Table 4, and the coating film characteristics were tested. The results are shown in Table 4. Tables 2 to 4 summarize the compounding conditions of the coating compositions of the above Examples and Comparative Examples and the evaluation results of the film properties. Curing conditions 140
The film formed at 30 ° C for 30 minutes is also cured at 80 ° C for 30 minutes.
The same result was obtained for the coating formed in a minute.

[0039]

[Table 2]

[0040]

[Table 3]

[0041]

[Table 4]

As can be seen from Tables 2 to 4, the coating compositions of the examples were 80% cured at 140 ° C. for 30 minutes.
Even at 30 ° C. for 30 minutes, adhesion, coating hardness, solvent resistance (curability), boiling water resistance, weather resistance and gloss were all good.

[0043]

The coating composition according to the present invention comprises at least the above specific (A), (B) and (C)
It consists of components and has a fast drying property. The cured film has high hardness and excellent adhesion, solvent resistance (curability), boiling water resistance and weather resistance, and especially gloss and smoothness of the coating film. Improved. Furthermore, since the coating composition of the present invention can be cured by heating in addition to curing at room temperature, it can be used in a wide range of drying conditions (environment) or temperature. Therefore, since it can be applied to a substrate having no heat resistance and can be applied at a work site where heat is not applied, its industrial and industrial value is extremely large.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Minoru Inoue 1048 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Works, Ltd. (72) Inventor Hiroshi Kimura 6-31, Roppongi, Minato-ku, Tokyo Toshiba Silicone Corporation (72) Inventor Yasutoshi Nagano 6-2-31 Roppongi, Minato-ku, Tokyo Toshiba Silicone Co., Ltd. (56) References JP-A-3-231925 (JP, A) JP-A-61-16927 (JP, A) JP-A-4-323281 (JP, A) JP-A-61-16928 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09D 183/04

Claims (1)

(57) [Claims] (A) R ¹ _n SiX _4-n ... (I) wherein R ¹ is the same or different alkyl group, cycloalkyl
Alkyl group, alkenyl group, halogen-substituted hydrocarbon group,
γ-methacryloxypropyl group, γ-glycidoxypro
Pill group, 3,4-epoxycyclohexylethyl group and
And selected from the group consisting of γ-mercaptopropyl groups,
A monovalent hydrocarbon group having 1 to 8 carbon atoms, n is an integer of 0 to 3, X is an alkoxy group, an acetoxy group, an oxime group,
From nonoxy, amino, aminoxy and amide groups
And a hydrolyzable group selected from the group consisting of In colloidal silica obtained by dispersing the hydrolyzable organosilane represented by the formula
A silica-dispersed oligomer solution of an organosilane, which is partially hydrolyzed under the conditions of using from 0.01 to 0.5 mol; (B) average composition formula (II) R ² _a Si (OH) _b O _{(4-ab) / 2} ... (II) (wherein, R ² is identical or different, an alkyl group, a cycloalkyl
Alkyl group, alkenyl group, halogen-substituted hydrocarbon group,
γ-methacryloxypropyl group, γ-glycidoxypro
Pill group, 3,4-epoxycyclohexylethyl group and
And selected from the group consisting of γ-mercaptopropyl groups,
Represents a monovalent hydrocarbon group having 1 to 8 carbon atoms, wherein a and b are 0.2 ≦ a ≦ 2, 0.0001 ≦ b ≦ 3, and a + b, respectively.
It is a number that satisfies the relationship of <4. A) a polyorganosiloxane containing 1 to 30 mol% of a phenyl group in R ² of the component relative to all R ² groups, and (C) condensation of the components (A) and (B) The catalyst which promotes the reaction is an essential component, and the component (A) contains 5-95% by weight of silica as a solid content, and at least 50 mol% of the hydrolyzable organosilane is n = 1 organosilane. ,
Component (B) 99-1 based on 1-99 parts by weight of component (A)
A coating composition containing parts by weight.