JPS58222160A - Coating composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. capable of forming coating films with high adhesive strength on the surface of moldings such as metals, said films being excellent in resistance to mar and abrasion and having good colorability, by incorporating a disilane compd. contg. a particular epoxy group as a constituent. CONSTITUTION:A coating compsn. contg. as a constituent, a compnd. of formula I [wherein A is a divalent functional group in which an epoxy group is contained, and the main chain consists of 6 or more atoms in a straight-chain (e.g., a group of formula II or III); R<1>, R<2> are alkyl, alkoxyalkyl; R<3>, R<4> are alkyl; l, m are 0,1]. Said coating compsn. is capable of forming coating films with high adhesive strength on the surface of moldings such as metals, which films being excellent in resistance to mar and abrasion and having good colorability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention makes it possible to form a coating film with high adhesion on the surface of molded products such as plastics and metals, which has excellent scratch resistance and abrasion resistance, and has good dyeability. The present invention relates to a coating composition.

Generally plastic molded products or aluminum.

Zinc metal molded product d: Due to its low surface hardness, it has drawbacks such as being easily scratched and easily abraded. In order to improve these problems, a method of forming a coating film of a curable substance on the surface of the molded article has been carried out, and various coating compositions have been proposed for forming the coating film.

For example, JP-A-53-78273, JP-A-48-55
No. 884 and US Pat. No. 4,027,073 disclose a coating composition comprising an alkyltrialkoxysilane or a mixture thereof with a tetraalkoxysilane or colloidal silica. However, the coating film obtained by heating and curing the coating composition after hydrolyzing it has excellent scratch resistance, but has poor adhesion to the surface of the molded product or flexibility of the coating film itself. Due to its poor adhesion, it peels off and cracks in hot water. Therefore, a method of providing an undercoat layer (amino acrylate thread) when coating with the coating composition has been disclosed (Japanese Patent Application Laid-Open No. 56-13847<S), but although the adhesion is improved by this method, it cannot be obtained. The coated film lacks smoothness, making it difficult to uniformly dye it with, for example, a disperse dye. On the other hand, coating compositions mainly composed of organoalkoxysilanes and epoxy resins containing epoxy groups have excellent adhesion and dyeability, but have low surface hardness, and in order to increase this, the mixing ratio of curing agents and crosslinking agents is When this value is increased, the dyeability and adhesion, which were originally good, become poor.

Therefore, the present inventors conducted intensive research to develop a coating composition that can form a coating film with excellent scratch resistance, abrasion resistance, and dyeing properties on the surface of plastic molded products with high adhesion. The inventors have now completed the present invention by discovering that a coating film obtained from a coating composition containing a specific group-containing disilane compound as a constituent satisfies all of these properties.

That is, the present invention provides a disilane compound containing an epoxy group represented by the general formula (wherein A is a divalent atomic group containing an epoxy group and having a main chain of at least 6 or more atoms in a straight chain). R1 and R2 are the same or different alkyl groups or alkoxyalkyl groups, R5 and R4 are the same or different alkyl groups,
and m is 0 or 1. ) is a coating composition.

The greatest feature of the present invention is that, as mentioned above, whereas conventional coating compositions contain only monosilane compounds as a constituent component, a disilane compound containing an epoxy group is used. The disilane compound (
5) Since the compound has 4 I and 6 alkoxy groups at both ends per molecule, the coat film formed by the polycondensation reaction of its hydrolyzate has a high crosslinking density and high surface hardness. It is thought that it has excellent scratch resistance, abrasion resistance, and solvent resistance. In addition, since the functional groups between 81 and 81 have a certain distance from each other, they are easily stained with molded products, and the coating film itself is elastic and has excellent flexibility, so it can be used to mold products using heat. It can respond to expansion and contraction, and exhibits excellent adhesion. Furthermore, since it has an epoxy group in its molecule, the adhesion of the coat film to the molded article is further improved, and the dyeability with disperse dyes is also good, making it easy to dye using ordinary dyeing methods.

Hereinafter, the coating composition of the present invention will be explained in detail.

In the disilane compound containing an epoxy group represented by the general formula (1), Hl; R2 is the same or different alkyl group or alkoxyalkyl (6) group, and the alkyl group has 1 to 6 carbon atoms, especially 1 to 3 carbon atoms. or an alkoxyalkyl group having 1 to 6 carbon atoms, especially 1 to 5 carbon atoms, bonded to an alkoxy group having 1 to 6 carbon atoms, especially 1 to 3 carbon atoms. Specifically, the methyl group.

Common examples include ethyl group, propyl group, and methoxyethyl group. Furthermore, R5 and R4 are the same or different alkyl groups, preferably having 1 to 4 carbon atoms. Specific examples include methyl group, ethyl group, and propyl group.

A contains an epoxy group, and the main chain is linear and has at least 6
A divalent functional group consisting of 1 or more atoms, exemplified by the following.

These disilane compounds containing an epoxy group represented by the general formula (1) can be synthesized by various conventionally known methods. That is, it can be synthesized by having a substituent having a double bond that can be added at both ends thereof, and further adding an epoxy group or a functional group xysilane such as an epoxidizable double bond inside the substituent. Alternatively, it may be trivial to carry out an addition reaction with a chlorosilane to be substituted for the alkoxyrane, and then perform alkoxylation with an alcohol represented by RiOH or R2oH. The above reaction conditions are not particularly limited, but are generally -20 to 160°C at normal pressure.
benzene if necessary.

The above reaction may be carried out in a polar non-aqueous solvent such as toluene or dimethyl ether. Further, it is preferable to use platinum black as the platinum catalyst since a colorless and transparent product can be obtained. For example, diallyl epoxysuccinate can be reacted with triethoxysilane under a platinum catalyst, hexatriene can be reacted similarly with jetoxymethylsilane under a platinum catalyst, and then the epoxy can be obtained by converting

In the present invention, it is preferable that the coating composition containing the epoxy group-containing disilane compound as a constituent component undergoes hydrolysis of the disilane compound prior to coating the molded article. It is preferable to use it in a polycondensed form (9) to exert a favorable effect. Hydrolysis of the disilane compound may be carried out by adding and stirring a weakly acidic aqueous solution containing an inorganic acid such as hydrochloric acid or sulfuric acid or an organic acid such as formic acid or acetic acid.

However, due to the heat generated by hydrolysis, polycondensation may proceed excessively, resulting in solidification of the reaction solution and shortening the life of the prepared coating composition. therefore,
The disilane compound is mixed with an appropriate solvent, preferably at a concentration (hereinafter referred to as converted concentration) of 60% by weight or less when the disilane compound is completely hydrolyzed and polycondensed, and then gradually It is desirable to hydrolyze it. In addition, in order to ensure that the hydrolysis reaction and subsequent partial polycondensation reaction proceed and to obtain reproducible and stable membrane performance, it is desirable to leave the reaction solution to mature. Appropriately, the period is about 1 to 2 days at room temperature.

The coating composition of the present invention contains alcohol which is produced as a by-product through the above-mentioned hydrolysis during use.

(lO) Alkoxy alcohol, unreacted water or solvent may be included, but these can be removed by distilling off the above components under heating and/or reduced pressure after hydrolysis; It is preferred to replace the solvent by adding a suitable solvent to the solution. The final coating composition has an equivalent concentration of 20 to 403ii
The amount percentage is too light and heavy; if it is less than this, it is difficult to obtain sufficient scratch resistance and abrasion resistance for the coated film that is formed, and if it is more than this, the viscosity increases and it is difficult to apply it uniformly to the surface to be coated. becomes. Suitable solvents for replacing the solvent include lower alcohols having 1 to 4 carbon atoms such as methanol, ethanol, propatool, and butanol; lower carboxylic acids or alkyl esters thereof such as acetic acid and methyl acetate; and ethers such as Serunlube. One or more of ketones such as acetone; logenated hydrocarbons such as methylene chloride; and aromatic hydrocarbons such as toluene and toluene.

As explained above, the coating composition containing the disilane compound represented by the general formula (1) as a component can form a coating film with excellent properties. The present invention also provides a coating composition that can improve the surface hardness of the resulting coat film by adding a specific compound to the compound.

That is, the present invention relates to a disilane compound containing an epoxy group represented by the general formula R1 and R2 are the same or different alkyl groups or alkoxyalkyl groups.

R3 and R4 are the same, and t3 is a different alkyl group.

and m is 0 or 1) and]
is a vinyl group, methacryloxy group.

A hydrocarbon group, an alkyl group, or an aryl group having one of a mercapto group, an epoxy group, and an amino group as a functional group, and an R6 haalkyl group where n is 0 or 1. R
7 is an alkyl group or an alkoxyalkyl group. )
.

General formula 8i (OR8) 4 -・・・・・・(3)
A tetraalkoxysilane compound represented by (however, R
8 is a furkyl group or an alkoxyalkyl group.

), colloidal silica, epoxy compounds, and at least one additive selected from melamine derivatives.

Among the above additives, the organoalkoxysilane compound represented by the general formula (2) is particularly suitable for R6 having 1 to 4 carbon atoms.
Those in which R7 has 1 to 4 carbon atoms are generally used. Specifically, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, ethyl (1rS
) trimethoxysilane, phenyltrimethoxy'/77
, polytriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrismethoxyethoxysilane, γ
- Glycidoxypropyltrimethoxysilane, r-glycidoxymethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane.

r-Mercaptopropyltrimethoxysilane.

Examples include β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and r-aminopropyltriethoxysilane. In addition, as for the tetraalkoxysilane compound represented by the general formula (3), one in which R8 has 1 to 4 carbon atoms is generally used. Specifically, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane,
Examples include tetrabutoxysilane. The above general formula (2
) and (3) are prepared using the same method as for disilane compounds (in this case, the alkoxysilane compounds shown in (3) are hydrated (
14) It is recommended that the product be used after being hydrolyzed (it is also possible to decompose it). For example, the alkoxysilane compound may be hydrolyzed and then added to the hydrolyzate solution of the disilane compound, or it may be hydrolyzed simultaneously with the disilane compound.

As colloidal silica, fine silica powder having a particle size of 1 to 100 mμ, which is produced by various conventionally known methods, can be used as it is or in the form of a colloidal solution obtained by dispersing it in a polar solvent. As for the composition of the present invention, a colloidal solution prepared by dispersing the colloidal silica in a polar solvent, for example, water or an alcoholic solvent such as impropatol, is preferably adjusted to be slightly acidic.

Epoxy compounds are manufactured by various conventionally known methods, and include "1" resin, alicyclic epoxy resin, epoxy novolac resin, polyglycidyl ether of polyhydric alcohol, etc. .

Melamine derivatives are commercially available mixtures of alkyl etherified methylolmelamine such as hexamethoxymethylmelamine with nitrified cotton, or! A precondensate with a polyhydric alcohol such as -1:1,4-butanediol can be prepared and used by a conventionally known method.

The total amount of the above additives is preferably in the range of 10 to 900 parts by weight, preferably 5 to 200 parts by weight, based on 100 parts by weight of the disilane compound.

The coating composition of the present invention uses known compounds such as hydrochloric acid and sulfuric acid as a curing catalyst in order to lower the curing temperature and shorten the curing time.

Acetic acid/acetic acid) IJium mixture, tin chloride, perchloric acid,
Aluminum acetylacetonate.

Naphthenic acid metal salt, :P-)luenesulfonic acid.

Benzoic acid, alkali metal phosphate, thiothia□,,.

It is preferable to use sodium chloride or the like.

The amount used is preferably 0.1 to 2 percent by weight based on the amount converted into a completely polycondensed state of the polycondensable components in the coating composition (hereinafter referred to as "converted amount"). Of course, the use of a curing catalyst is not essential.

Further, a silicone-based or fluorine-based surfactant can be added to the coating composition of the present invention for the purpose of further improving the smoothness of the coated film. In addition, various other additives such as ultraviolet absorbers, antioxidants, dyes and pigments, and organic carboxylic acids such as formic acid and acetic acid as gelling inhibitors can also be used.

In the present invention, there are no particular restrictions on the objects to be coated, and the objects are generally molded products with low surface hardness and poor scratch resistance and wear resistance, particularly plastic molded products.

For example, polymethyl methacrylate, polymethacrylate, polyethylene terephthalate.

Polyunsaturated esters such as polyacrylate and polymethyl acrylate; polystyrenes: polyvinyl chloride; epoxy resins; polyamides; polycarbonates; polyallyl carbonates such as recall bisallyl carbonate; cellulose acetate Examples include molded articles made of polymers such as plastics, or copolymers of monomers forming these polymers or copolymers of the monomers and other monomers. Among them, polymethacrylic acid esters.

For plastic molded products with excellent transparency made of polymers such as polyacrylic acid esters, polycarbonates, polyallyl carbonates, etc., the coating film obtained from the coating composition of the present invention has high transparency and a good appearance. It is particularly effective in that it does not lose its optical properties. Please note that the surface condition of plastic molded products greatly affects the properties of the resulting coating film.
It is preferable to clean the surface by degreasing and washing with a solvent. In addition, if the adhesion of the coating composition of the present invention is insufficient depending on the plastic fabric, for example, for (18) plastic molded products such as polycarbonates and styrene thread polymers, aqueous sodium hydroxide solution 1 potassium dichromate/potassium dichromate/ Reagent treatment with sulfuric acid solution, etc.
Known methods such as plasma discharge treatment or primer coating are effective for improving the adhesion between the plastic molded product and the coating film. It is further preferred that the discharge treated surface substantially dissolves the plastic and dissolves the layer modified by the treatment with a solvent.

＼. 9) The method of applying the coating composition of the present invention to the surface of a glass molded article can be used without any particular restrictions. For example, a method in which a molded article is immersed in a solution of a coating composition, a method in which the solution is applied by a spray, a brush, a roller, etc. are generally employed. After coating, the coating is cured by drying in dry air or air, and usually by heat treatment to form coat IIU. The heating temperature varies depending on the molded product, but is preferably 50° C. or higher, preferably OC, or a temperature at which the molded product does not undergo thermal change, generally 750° C. or lower.

The curing time is approximately 7 hours at a heating temperature of /300, 70-1
A rough guideline is approximately 2 to 9 hours at 0°C.

The coat film formed by curing can have a thickness of about 0.7μ to SOμ, but a thickness of /μ to 20μ is particularly suitable.

The coat, Group 5, formed from the coating composition of the present invention in this way has excellent surface properties such as scratch resistance, abrasion resistance, dyeability, hot water resistance, and heat resistance. EXAMPLES Hereinafter, practical examples will be shown to specifically explain the present invention, but the present invention is not limited to these examples. Performance evaluation of the coated film was carried out by the following method.

0) Adhesion test: After making 700 /×/■ squares on the sample surface with a cutter knife with a sharp tip, apply commercially available cellophane tape and quickly peel it off to determine the number of squares remaining. It was displayed in

(2) Scratch resistance test; Attach steel wool of OOOθ to a scratch resistance tester made by Fukuda Kikai Kogyo ■, /~
After reciprocating the surface of the test piece 10 times under a load of - Evaluated at S stage of E.

(3) Heat resistance test: The coated film was left in an air oven set at 730° C. for 3 hours, and the appearance of the coated film was visually observed. If the coat film had no cracks, peeling, blistering, whitening, etc. and had a good appearance, it was rated as ○, and if it was poor, it was rated as ×.

(4) Hot water resistance test: The coated film was left in boiling water (for polymethyl methacrylate, hot water at gθ°C was used) for a period of time, and the appearance of the coated film was visually observed.

If the coat group had no peeling, blistering, cracking, whitening, etc. and had a good appearance, it was rated ○, and if it was poor, it was rated ×.

(5) Dyeability test: 0.5 parts by weight of disperse dye (manufactured by Nippon Shigyo Co., Ltd., Kayalon Polyester, PlowyAF) in 1 part of water.
The dyeing bath in which 00 parts by weight was dispersed and dissolved was kept at gθ℃, and 1
Stained for 0 minutes. A1 is the case where the dyeing is as good as or better than that of polydiethylene glycol bisallyl carbonate, which shows good stainability, and C is the case where it is not dyed to the same level or worse than polymethyl methacrylate, which has poor stainability, and A- Evaluation was made on a three-level scale of C.

Example: A commercially available polymethyl methacrylate plate was used as a plastic molded article. After washing with methanol and thoroughly air-drying it to a clear state, it was coated with a coating composition having the composition shown in Table 1. After soaking and thoroughly air-drying at room temperature, gθ
It was cured by heating at .degree. C. for 3 hours to obtain Coat III. The coating composition has a concentration equivalent to that of the composition shown in Table 1.
Amounts of each phase were mixed and dissolved in isonorobyl alcohol as a solvent so that the concentration was 0.0 cm, and then an equivalent amount of O,OS normal sulfuric acid necessary for hydrolysis of the alkoxy group with the above composition was added at room temperature. After addition and aging for 7 days, sodium acetate/acetic acid (rice bundle weight ratio) was added as a curing catalyst in an amount of 2% by weight based on the amount of A/A. The same colloidal silica is 0SCAL (product name: S10□ 3) made by Catalysts and Chemicals.
0 wt-m-percent, particle size 10-λθmμ, solvent (isopropyl alcohol) was used. Table 2 also shows the evaluation results of the coating films obtained from each coating solution. In either case, the coating film thickness was approximately S to 70μ.

EXAMPLE A polyethylene glycol bisallyl carbonate plate produced by green mold polymerization was used as a coplastic molded article. First, as a pretreatment, the plate was washed with acetone and thoroughly dried with KK to make it clear.
mln / / 0ynl/mln) Pressure Q, '
Processed under the conditions of 7 Torr, output 200 W, and processing time 7 minutes, and then an ultrasonic cleaner using acetone as a solvent for 5 minutes! It was washed with il- and air-dried again.

The above-treated plate-like bodies were immersed in coating compositions prepared in exactly the same manner as in Example A/~// except that no curing catalyst was added, and then sufficiently air-dried at room temperature and heated to 100°C for 2 hours. The coated film was obtained by heating and curing for a period of time. Table 2 shows the evaluation results for coat i obtained from each coating composition. In either case, the coating film thickness was approximately S to 70μ.

(2 ke 2 Table - (λL) Application examples/Example ko/~//, Corbis (4z-(i
t-methacryloxy)-ethoxy-3,3-dibromophenyl cupropane and styrene copolymer (hereinafter referred to as T
Coat Mh was obtained by pretreatment and coating treatment in the same manner except that a plate-like body made of B-styrene copolymer (referred to as B-styrene copolymer) with a TB/styrene shearing ratio was used. Evaluation of the Samurai coating film from each coating composition.
7 baths on the clothes.

In either case, yJN is approximately 5.about.10μ and fc.

(-') Table 3 Example q In the plate S of Example /, glycol diglycidyl ether (Kyoeisha Yushi Co., Ltd., Epoliteco θQE) or hexamethoxymethylmelamine sown part and /, 4-butanediol! It is produced by cast polymerization using a coating composition to which the same amount of a precondensate consisting of rOM and a precondensate is added. A plate-shaped body of a combination of polyl diethylene glycol bisallyl carbonate and TB/styrene was pretreated and coated in the same manner as in Example C to obtain a coated film. In either case, the adhesion of the coating film <100/10θ), the scratch resistance (A
l, heat resistance (O), hot water resistance f! (0), and the stainability (A) was good.

Example S A plate of polyethylene glycol bisallyl carzenate produced by cast polymerization and a TB/styrene copolymer was pretreated in the same manner as in Example A, and the same preparation method as in Example After being immersed in a coating composition having the various compositions shown in Table 9, it was sufficiently air-dried at room temperature, and then heated and cured at 10OC for 2 hours to obtain a coat film. In either case, adhesion (/θ0/100) and scratch resistance (A
) Heat resistance, hot water resistance, and dyeability (A) were good.

\ Application example = After cleaning an aluminum plate with acetone and air-drying it to a clear state, it was coated by dipping it in the coating solution A5 shown in Table 1. After being air-dried with light at room temperature, it was heated and cured at 730°C for 7 hours. . The obtained coat film has adhesion (/00//θ
0), Scratch resistance (A), Heat resistance (0), Hot water resistance (0)
is good and rare.

Example 6 A coating composition was prepared in the same manner as in Example A3 except that the following disilane compound having the atomic group (-A-) shown in Table 5 was used as the disilane compound)
did.

(OEt) 2Si-A-3i (OEt) 2 Using the coating composition, coating was carried out in the same manner as in Example to form a coated film. The evaluation results of the coated film are also shown in Table 5.

(3λ) (33)

Claims (1)

[Claims] A disilane compound containing an epoxy group (provided that
A: A divalent atomic group containing an epoxy group and having a linear main chain of at least 6 atoms + R' and R2 are the same or different alkyl groups or alkoxyalkyl groups H5 and R4 are the same or different an alkyl group, and m
is 0 or 1) is a disilane compound containing an epoxy group (however,
A is a divalent functional group containing an epoxy group and having a linear main chain of at least 6 or more atoms, R1 and R4 are the same or different alkyl groups, and m is O or 1). 〒n An organoalkoxysilane compound represented by the general formula R5-81(OR7)3-n (However, R5 is a vinyl group,
Methacryloxy group, mercapto group. Hydrocarbon group, alkyl group, or aryl group having one of epoxy group and amine group as a functional group
R6 is an alkyl group and n is 0- or 1. R7 is an alkyl group or an alkoxyalkyl group. ), at least one additive selected from tetraalkoxysilane compounds represented by the general formula S (OR8)4 (wherein R8 is an alkyl group or an alkoxyalkyl group), colloidal silica, epoxy compounds, and melamine derivatives. A coating composition comprising