JPS6081256A - Coating composition - Google Patents

Abstract

PURPOSE:A coating composition, obtained by incorporating a mixture of an ethyltrialkoxysilane with a trialkoxysilane, etc. or further a cohydrolyzate thereof with silicic acid anhydride in a specific proportion, capable of giving films having improved abrasion and weather resistance and flexibility, and useful for molded plastic articles. CONSTITUTION:A coating composition obtained by incorporating (A) 100pts.wt. mixture consisting of (i) 100-30wt% ethyltrialkoxysilane of the formula C2H5Si(OR<1>)3 (R<1> is 1-4C alkyl) with (ii) 70-0wt% trialkoxysilane of the formula R<2>Si(OR<1>)3 (R<2> is H, methyl, vinyl or phenyl) and (iii) 30-0wt% organosilicon compound of the formula [R<3> and R<4> are alkyl; R<5> and R<6> are (substituted) monofunctional hydrocarbon; A is bifunctional hydrocarbon or a bifunctional organic group containing oxygen or sulfur; a and b are 2 or 3] or a cohydrolyzate thereof with (B) 200-50pts.wt. colloidal silica containing 10-50wt% silicic acid anhydride.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a coating composition, particularly a coating silicone composition that provides a coating with excellent toughness, weather resistance, and flexibility, and is suitable as a surface coating material for various plastic molded products. It is about things.

Although plastic molded products are currently widely used for various applications, they have low hardness.

It has the disadvantage that its wear resistance is low, so it is easily scratched, and its weather resistance is also poor, which limits its uses. Therefore, for this type of molded product, there is a method of treating the surface of the product with a coating agent in which colloidal N9 is dispersed in a lower aliphatic alcohol solution of a partial condensate of methyltrialcoquine silane [JP-A-51-1993]. No. 2736 @] has been proposed, but the film obtained by this method cracks when immersed in hot water, is susceptible to heat shock, and cracks when heated for a long time.

As an improvement method for this, a method of introducing phenyltrialkoxysilane in the above-mentioned method [JP-A-53-1999
130732 @], and a method of introducing dimethyldialkoxysilane [see especially i3fM Publication No. 53-92844] has also been proposed, but this former method is difficult because phenyltrialkoxysilane is a trifunctional silane. Essentially, no major modification effect can be obtained, and although increasing the amount of dimethyldialkoxysilane added can prevent cracking, in this case, the adhesion to the substrate changes and the hardness decreases. There were drawbacks.

The present invention relates to a coating composition which solves these disadvantages, and which comprises an ethertrialkoxy compound represented by the formula C2H551(OR1)3 (wherein R1 is an alkyl group having 1 to 4 carbon atoms). Silane 100-30 tonne% 11) Trialkoxysilane represented by the formula R25i(OR')3 (where R1 is the same as above, R2 is a hydrogen atom, methyl group, vinyl group or phenyl group) 70-0 weight % 1) I) General formula (R30) aS IA S l (O
R') b, (2R, R are the same or different alkyl groups, R5 and R6 are the same or different unsubstituted or substituted monovalent hydrocarbon groups, A is a divalent hydrocarbon group or an oxygen atom or a sulfur atom or a co-hydrolyzate thereof:
r part 1'J! It is characterized in that I' is comprised of 200 to 50 parts of colloidal silica containing 710 to 51% of silicic acid and 14%.

this? To be clear, the present inventors conducted various studies on coating compositions for surface modification of plastic molded products, and as a result, specifically selected ethyltrialkoxysilane Y iM as the trialkoxysilane, and added the above-mentioned A)
-iii) Special organosilicon compound as a component and B]
When a plastic molded product is coated with a composition containing colloidal silica as an ingredient, the film has excellent flexibility, RT01 weatherability, and adhesion.
Having discovered that the drawbacks of conventional products such as cracking and poor adhesion can be solved, the present invention was completed by carrying out research on each of these components and their addition amounts.

This is a diagram of the acid component (A) that constitutes the coating composition of the present invention.

Component I) is of the formula C2H551(oRl)3.

R is an alkyl group having 1 to 4 carbon atoms, such as one selected from ethyltriorganosilanes such as ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, and ethyltriisobutoxysilane. is a mixture of two #111 or more, II)
The components are represented by the formula R'5l(OR')3,
R is an alkyl thread having 1 to 4 carbon atoms, R is a hydrogen atom, a methyl group, a vinyl group, or a phenyl group, such as trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxy One or more alkoxysilanes selected from silane, vinyltriethoxyv-ray, phenyltrimethoxysilane, phenyltriethoxysilane, and the like. moreover,! 11) The component is an alkyl group in which R and R are the same or different.

Preferably, an alkyl group having 1 to 4 carbon atoms, R5 and R6 are the same, F or I is a face-pressed non-II monosubstituted or direct monovalent hydrocarbon, and A is preferably a divalent hydrocarbon having 2 to 6 carbon atoms. carbon, preferably containing an oxygen atom or a sulfur atom
3~] 0 divalent] is considered to be ↓, and for this person, methylene group, ethylene group, propylene J, % 7
j Which alkylene group or aryl group such as phenylene group
Examples include groups such as Lenz, %, groups in which the hydrogen atoms of these groups are partially substituted with halogen atoms, alkyl groups, etc., and groups such as the formula % and the formula %. Note that a and b are 2 or 3
The compounds represented by formula 111) are exemplified below.

(OH30)28i-OH20H2-8i (002H
5) 21(CH30)3Si-CH20H2-8i(O
CH3) 3゜OH3 (OH30)2Si-OH2CH2-8i (OCH3)
3゜OH3CH3 1 (OH30)2Si-OH20H2-8-OH20H2
0H2-8i (OCH3)2゜OH3CH3 1 (OH30)2Si-OH20H20H2-0-CH2
0H20H2-3i (O0H3)2゜(OH30)3
Si-OH20H20H2-8-OH20H20H2-
8i (OCH3)3゜The above-mentioned organosilicon compound as the component (11) can be synthesized by various conventionally known methods, such as (RO)aSi-Y (where Y is di- or trialkoxysilane represented by a halogen atom or alkoxy group) and X -Mg-A-
A method of reacting a Grignard compound represented by Mg -X (where X is a halogen atom) with the formula R3-a Akebono < R30) and an alkoxymonohydrodiene silane represented by Si -H and the formula R3-b < R40) b S x R7 (here R7 is a monovalent hydrocarbon group containing an aliphatic unsaturated bond)
A method of addition-reacting an alkoxysilane represented by R,a in the presence of a platinum-based catalyst with an alkoxysilane containing an unsaturated bond-containing monovalent hydrocarbon group under ultraviolet irradiation or in the presence of an organic peroxide. Addition reaction method, furthermore, the alkoxymonohydrodiene silane shown in the above formula and the formula R-D-R10 (where R and R are monovalent hydrocarbon groups containing an aliphatic unsaturated bond, and D is a divalent hydrocarbon group) or a divalent organic group containing an oxygen atom)! It can be synthesized by an addition reaction method in the presence of a platinum-based catalyst.

This person] Component Z must contain at least % by weight of the components 1), I+), and 111). it ), fil
) The ingredients are.

Component 11) is used to increase the hardness of the film, although it is not necessarily essential for this composition.
If the lijiJ% is too high, the resulting film will be brittle and prone to cracking, and the 111) component will be
It is added to give flexibility to the film. If this component exceeds 30% by weight, the resulting film will have too low elasticity and its adhesion will decrease, so it should be kept at 30% by weight or less. It is. For the above reasons, l), li),
It is more preferable to use component 1il) in combination.

Next, the colloidal silica as the acid component (B), which constitutes the entire composition of the present invention, contains silicic anhydride at 10 to 50 F, 1%
The commonly available commercial products Ludotux (trade name manufactured by Shubon, USA), Cyton (trade name manufactured by Monnant Corporation, USA), Nalcoke (trade name manufactured by Nalco, USA), and Snorax (trade name manufactured by Nissan Chemical Co., Ltd.) company product name), etc. If the amount of colloidal silica added is 50 parts by weight per 100 parts by weight of component A, the film will become softer in terms of hardness and cracks will be more likely to occur in the heat shock test. ,
If the coating layer has a coating density of 200 layers or more, a clouding phenomenon will be observed in the appearance of the film, and transparency will be lost. In addition, as the water contained in colloidal silica as a coating agent increases, the life of the liquid becomes shorter.
However, since this stabilizes the composition of the present invention and improves the physical properties of the film obtained from it, the particle size should be within the range of 7 to 50.
Preferably, the thickness is in the μm range.

The composition of the present invention comprises the above-mentioned A] acid components 1) and II).
, 1) and B) may be simply mixed with the total phosphorus, but preferably A] acid component f4 I), I
I), In) components are partially condensed, and then B]
It is adjusted by adding an acid component. Although this partial condensation reaction differs slightly depending on the particle size of the colloidal silica, which is the acid component (B) added next, it is usually carried out at room temperature.
It may be heated for 10 to 15 hours at 40 to 60°C for one day to one week. In addition, for the purpose of preventing gelation and obtaining a film 7 with excellent properties, the composition has a pH of 3.0 to 7.
It is preferable to use a silicic acid such as formic acid, propionic acid, propionic acid, maleic acid, etc. for this pH adjustment of 21°. In addition, this composition is said to contain alcohol, which is a by-product of the condensation reaction, but if necessary, it may be dissolved or dispersed in any organic solvent, water, or a mixture thereof. Examples of solvents include lower fatty acid alcohols such as methanol, ethanol, n-propanol, and isobutyl alcohol, polyhydric alcohols such as ethylene glycol, methyl cellosolve, and ethyl cellosolve, or their esters, ethers, acetone,
Examples include water-soluble solvents such as methyl ethyl ketone, tetrahydrofuran, and dioxane. Among these, lower fatty acid alcohols, glycol monoesters, or mixtures thereof are preferred, but two or more of these are used in combination. In this case, it is preferable to use a lower fatty acid alcohol containing 20 to 75% by weight of siloxanol to ensure its dissolution. This composition also contains various surfactants, such as polyoxyalkylene glycol-dimethylsiloxitin copolymer KR-341, for the purpose of completely improving the smoothness of the film formed on the substrate by this composition. [: Shin-Etsu Chemical Co., Ltd., trade name], fluorinated alkyl surfactant Flochy) FO-340 (Ryoe Chemical Co., Ltd., trade name) etc. is added in an amount of 0.02 to 0.1% by weight to this composition. In addition, an ultraviolet absorber may be added to this composition, so that, for example, when this composition is applied to a polycarbonate surface, it completely prevents discoloration of the surface. As this ultraviolet absorber, benzophenone type, triazole type, salicylic acid type, etc. are used.
From the viewpoint of compatibility with the composition of the present invention, this is preferably dihydroxybenzophenone, which may be added in an amount of 0.2 to 2.0% by weight based on the composition.

The composition of the present invention is applied to the surface of the target substrate by brush coating, dip coating, spin coating, spray coating, flow coating, roller coating, etc., and then heated at 60 to 150°C.
When heated for 30 to 120 minutes at a temperature of 11
This application (t means that the thickness of the film after drying is 1.0 to 10 μm).
What is necessary is to make it m. This film is heated as described above to undergo six-layer heating, which is caused by alkali metal salts of fatty acids,
A known condensation catalyst such as a quaternary ammonium salt or quaternary ammonium hydrooxide may be added, but the above-mentioned colloidal silica may be used as a stabilizer.
20 'a:' If it contains, this is A] It reacts with the organic acid used as a pH 8 adjusting agent when mixing the acid components to form sodium acetate, etc., which acts as a curing catalyst, so in this case, There is no particular need to add this.

The film formed on the substrate surface by the composition of the present invention is A]
It has an acid component ethyl group, especially A 3-11.
+) Because of the added ingredients, it has excellent flexibility, so it can be bent and processed.
This composition also has a crack-preventing effect and has excellent heat resistance, so this composition can be used for transparent plastic plates made of polymethacrylate resin, polycarbonate resin, polyvinyl chloride resin, polystyrene resin, etc. It is said to be useful as a surface modification material for plastic lenses or plastic films, but if the composition, film formation conditions, and pretreatment conditions for the base material such as primer treatment are appropriately selected, it can be used as a surface modification material for aluminum, iron, steel, etc. It also shows remarkable effects on metal surface treatment.

Next, examples of the present invention will be given. The parts in the examples show the treated parts, and the physical properties of the films in the examples show the results of measurements by the following method.

1)l! 1) Steel wool test Surface resistance of the film obtained by applying the coating composition to the substrate surface #○
I rubbed it hard with ○○○ steel wool and checked the extent of the scratches.

a...No scratches b...Slight scratches C...Significant damage +1') Taber 1 Sakai abrasion test Using Taber abrasion tester (newly manufactured by Toyo Seiki Seisakusho) 7, load 5
After rotating the 00 g abrasion wheel (8-10) 100 times, the haze was measured using a haze meter (newly manufactured by Toyo Seiki Seisakusho).

2) Adhesion (burlap test) On the film formed by applying the coating composition, 7100 squares with one side of 1 mj++ were made by making 11 scratches vertically and horizontally at IH intervals, and the adhesive was applied on top of the scratches. A tape (manufactured by Chiban Co., Ltd., trade name) was adhered to the tape/cellotape, and the number of squares (Z) that did not peel off was counted by peeling it off.

3) Weather resistance test Using Atlas Yufucon (manufactured by Toyo Sei In Seisakusho, trade name) 7, UV exposure time 10°C, 8 hours, wet 1b dew time 1
One cycle is 4 hours at 0℃, and a test is performed to determine if the film has deteriorated, and the time until peeling is determined! It was measured.

4) Bending workability Primer PO-4 (part name manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to a polyh-board board of 200B x 100M x 1wIL, and after air drying for 10 minutes, the coating composition was applied. Coat it and heat it at 120'C for 60 minutes to form a film, then heat it at 170°C for 120 seconds, then bend it along a cylindrical round bar (wooden) with a diameter of 100mm. The occurrence of crank was observed.

Example: Ethyltrimethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane from the companies shown in Table 1, organosilicon compounds A, B, c, and D4tLf shown below and 1.6 parts of acetic acid. After mixing and cooling in a water bath, the temperature was maintained at 0 to 10°C without stirring, and colloidal silica-Snorax (mentioned above, average particle size 5 to 10 mμ) was gradually added dropwise to the mixture until the temperature reached the end of the dropwise addition. 'i'IO'C and stirred for 4.5 hours, then 100 parts of Impropatool, 2.3 parts of acetic acid and polyoxyethylene glycol/dimethylsiloxitin copolymer KR-341 (
After adding 0.08 parts (as mentioned above), let it cool to room temperature for 7
The coated compositions 1 to 17 were prepared by leaving to mature for several days.

For further comparison, coating compositions 18-26 were prepared above without the addition of ethyltrimethoxine and/or organosilicon compounds.

(Organosilicon compound) 00H3002H6 O0H300H3 00H300H3°H30H3 1 00H300H3 Next, the coating composition obtained above was applied to the temporary surface of Polymethyl Methacrylate Plug Glass A (manufactured by Asahi Kasei Co., Ltd., trade name) by a dipping method.

This was heated at 80° C. for 120 minutes to make it afh, and when one sample of this ()-use compound was tested, the results shown in Table 2 were obtained.

Claims (1)

[Scope of Claims] 1. A) l) xf trialkoxysilane 100 to 30 [; 1% II ) Trialkoxysilane represented by the formula R2Si (OR' )3 (where R1 is the same as above, R2 is a hydrogen atom, a methyl group, a vinyl group or a phenyl group) 70
~0 East4i, E%11ri General formula (R30)aSi
-A-3i (OR')b (where R3 and R4 are the same or different alkyl groups, R5 and R6 are the same or different unsubstituted or substituted monovalent hydrocarbon groups, A is a divalent hydrocarbon group, or A divalent organic group containing an oxygen atom or a sulfur atom, a and b are 2 or 3), an organosilicon compound represented by 30 to 0% by weight, or a cohydrolyzate thereof 100 @
t'i Part B] A coating composition comprising 200 to 50 parts of colloidal silica containing 710 to 50% by weight of silicic anhydride.