JPS61221282A - Prevention of surface contamination - Google Patents

Abstract

PURPOSE:To prevent surface contamination of molded product caused by dust and oily components, by applying uniformly a solvent solution of alkyl silicate containing a specified trace amount of Si to the surface of molded product, followed by drying. CONSTITUTION:A solvent solution of 2-18C alkyl silicate having an Si content of 0.05-0.0003wt% is applied uniformly to the surface of molded product consisting of thermoplatic resin, thermosetting resin, metal and inorganic mate rial, followed by drying. Formed alkyl silicate film prevents surface contamina tion due to dust and oily components, etc. The alkyl group of the alkyl silicate should pref. be a secondary alkyl group. When two or more alkyl silicates are used, at least one of them should pref. have a secondary alkyl group. The treatment is done by coating or interweaving.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to the prevention of stains caused by dust, oily components, etc. generated on the surfaces of molded products made of thermoplastic resins, thermosetting resins, metals, and inorganic materials.

Conventional methods Usually, various types of dirt easily adhere to the surface of molded products, such as molded products made of thermoplastic resins, thermosetting resins, metal molded products, and inorganic molded products. This is a factor that significantly impairs the appearance and reduces the product value.

Conventional countermeasures include blowing away with a brush or wind, removing with corona discharge, and coating with various antifouling agents, but these methods are only temporary.

The durability of stain prevention was poor, and the product was not sufficient.

Most of the dirt on solid surfaces is caused by static electricity, such as dust. Therefore, the development of static electricity generation inhibitors was closely related to the stain prevention method.
5. Japanese Patent Publication No. 32-59.46 discloses a method in which a colloidal solution obtained by the reaction of silicon tetrachloride and a monovalent aliphatic alcohol is applied to the surface of a synthetic resin to impart antistatic properties.

Also, Polyfile 198
The April 2018 issue (published by Taiseisha) introduces the idea of adding conductivity to prevent static electricity and lowering the resistance value of plastic below a predetermined value.

As a common point among these, it is thought that a compound of Sl is effective in preventing staining, that is, preventing static electricity.

Purpose of the present application The present inventor has made extensive research into the effects of alkyl silicates as an extension of these ideas.

It has been found that the method of the present invention, which will be described in detail below, is extremely superior in practice.

The stain prevention method of the present invention involves applying an alkyl silicate to the surface of various molded products such as thermoplastic resin molded products, thermosetting resin molded products, metal molded products, and inorganic molded products to prevent stains. There are two methods: a coating method and a kneading method in which the thermoplastic resin is added to the thermoplastic resin and kneaded together with other commonly used compounding agents to prevent staining.

The alkyl silicate according to the present invention is composed of 4 moles of first and second monohydric alcohols having 2 to 18 carbon atoms and 1 silicon tetrachloride.
It is obtained by reacting moles.

The first and 1g2 monohydric alcohols are preferably a single alcohol or a mixture of two or more alcohols having a carbon number of 2 to 18.

The first 1 (i
-Hephthyl alcohol, n-octyl alcohol, 2-
Ethyl hesacyl alcohol, n-nonyl alcohol *n
- Decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, vinyl alcohol, allyl alcohol.

It refers to crotyl alcohol, allyl carbinol, oleyl alcohol, etc.

Further, the second monohydric alcohol includes isopropyl alcohol, 5ec-butyl alcohol, 2-pentanol, methylimpropylcarbinol, methylvinylcarbinol, and the like.

Both the first and second alkyl groups of the alkyl silicate are effective in preventing staining, but surprisingly it has been found that the second alkyl group is more effective than the first.

This phenomenon occurs when the alkyl group of the alkyl silicate is a secondary alkyl group, and the plume is rapidly hydrolyzed, so the hydrolyzed product is likely to trap and fall off from the surface of the molded article (peeling effect). Become. Therefore, the second
It is thought that the antistatic effect and release effect of silica act synergistically with furkyl silicate, and furthermore, the antifouling effect is exhibited. In addition, when one or more types of alkyl silicates are used as a mixture.

It is preferable that at least one of them is a secondary alkyl group, which provides long-lasting stain prevention.

Surface coating method In the case of stain prevention using the surface coating method of the present invention.

This method involves uniformly applying an alkyl silicate coating liquid prepared with a diluting solvent so that the Si content of the alkyl silicate is 0.05 to 0.0005 on the surface of various molded products.

The molded products mentioned here are phenol and urea.

Refers to thermosetting resin molded products such as melamine, polyester, and silicone, metal molded products, inorganic molded products such as glass and ceramic, and thermoplastic resin molded products.

The diluting solvent mentioned here is methyl alcohol, the same alcohol used to synthesize the alkyl silicate mentioned above.

Cyclohexanol, 2-methylcyclohexanol,
Alcohols such as benzyl alcohol, phenoxyethanol, methoxyethanol and methoxybutanol,
Ketone organic substances such as acetone, methyl acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl isobutyl ketone, ingropanolamine, N.

Nitrogen compounds such as N-dimethylformamide.

Ethylene glycol, diethylene glycol.

Glycols such as triethylene glycol and propylene glycol, ethylene glycol monomethyl ether,
Glycol ethers such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, methyl cellosolve, and ethyl cellosol butyl cellosolve.

n-hexane, n-hebutane, n-octane.

Petroleum ether, petroleum benzine, ligroin, gasoline,
Kerosene 9 Petroleum Spirit, Petroleum Naphtha.

Cyclohexane, methylcyclohexane, benzene, toluene, xylene, ethylbenzene.

Hydrocarbons such as diethylbenzene, trimethylbenzene, amylbenzene, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, acrylic (meth)acrylate (meth)acrylic acid esters such as

Surface coating methods include spraying, dipping, and brush coating, which are commonly used.
This is a method in which a coating solution prepared by adjusting an alkyl silicate with a solvent so as to have a weight percent of ~0,000% is spread evenly over a kilometer, and drying may be done by either natural drying or heat drying.

When an alkyl silicate coating liquid with an S1 content of 105% or more is applied uniformly,! ! ! After drying the cloth, the surface of the sheet and molded product becomes cloudy.

It damages the appearance of the product and significantly reduces the quality.

Further, when an alkyl silicate coating liquid containing S1 content of α0005 weight or less is uniformly applied, the effect is weak and it is not practical.

When an alkyl silicate coating liquid adjusted with a solvent to have an S1 content in the range of 0.05 to 0.0005% by weight is applied uniformly, the stain prevention effect is significantly improved without impairing the transparency or quality of the molded product itself. Ru.

kneading method In the case of stain prevention using the kneading method of the present invention.

Directly wire the alkyl silicate without diluting it with a diluting solvent. The above-mentioned alkyl silicate is added to 100 parts by weight of the thermoplastic resin so that the Si content is 11 to 0.0005 parts by weight, and the mixture is kneaded together with other commonly used compounding agents.

The thermoplastic resins mentioned here include polyolefins such as polyethylene, polybutene, polypropylene, poly-3-methylbutene, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, and copolymers thereof, polyvinyl chloride, and polypropylene. Vinyl bromide, poly(7) vinylide,
Polyvinylidene chloride, chlorinated polyethylene, chlorinated polypropylene, polyvinylidene fluoride, brominated polyethylene, chlorinated rubber, vinyl chloride-vinyl acetate copolymer, vinyl chloride-ethylene copolymer, vinyl chloride-propylene copolymer, vinyl chloride -Styrene copolymer, vinyl chloride-
Isobutylene copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-styrene-acrylonitrile copolymer, vinyl chloride-butadiene copolymer, vinyl chloride-
Imprene copolymer, vinyl chloride-chlorinated zuropyrene copolymer, vinyl chloride-acrylic ester copolymer, vinyl chloride-maleic ester copolymer, vinyl chloride-
Halogen-containing synthetic resins such as methacrylic acid ester copolymers, vinyl chloride-acrylonitrile copolymers, internally plasticized polyvinyl chloride, polystyrene, polyvinyl acetate, acrylic resins, styrene and other monomers (butadiene, acrylonitrile, anhydrous (maleic acid, etc.), acrylonitrile-butadiene-styrene copolymer, methacrylic ester-butadiene-styrene copolymer, acrylic ester-butadiene-styrene copolymer, methacrylic ester-butadiene-styrene copolymer Union,
methacrylate resins such as polymethyl methacrylate,
Polyvinyl alcohol, polyvinyl formal.

There are polyvinyl butyral, polycarbonate, etc., as well as imprene rubber and butadiene rubber.

Acrylonitrile-butadiene copolymer rubber, styrene-
Refers to rubbers such as butadiene copolymer rubber and blends of these resins.

This will be explained in more detail below using Examples.

Throughout the surface coating method and kneading method, the following method was used to adjust the alkyl silicate.

Preparation A: Synthesis of alkyl silicate 1 mole of silicon tetrachloride was gradually added dropwise to 4 moles of various alcohols using a dropping funnel.

The reaction was carried out for 2 hours at room temperature in a nitrogen atmosphere at 60 DEG C. under an aspirator vacuum of 50 mmHf for 5 hours and 9 hours, and the generated hydrochloric acid was completely removed to obtain various alkyl silicates. The pH of these products was neutral at zO.

B. Adjustment of alkyl silicate coating solution The alkyl silicate obtained above was diluted with a diluting solvent, and the Si content in the resulting solution was adjusted to a predetermined value.

The degree of staining was evaluated by visual observation after exposing the materials outdoors for one year using the JIS A 1410 outdoor exposure test method for plastic building materials.

Contamination is judged using the following evaluation criteria.

Evaluation 1: Not much at all 2: Somewhat 3: Somewhat a lot 4: A lot 5: Quite a lot 6: Remarkable Example 1. (Surface coating method) Ethyl alcohol was used as the alcohol to synthesize the alkyl silicate, and methyl alcohol was used as the diluting solvent to prepare the solution.

This coating solution was evenly applied to a commercially available 0.1 m soft vinyl chloride sheet using a bar coater and dried.

After being exposed outdoors for one year, the degree of staining was visually determined.

Table 1 Example 2 (Surface coating method) Various alcohols shown in the following table were used to synthesize alkyl silicate, and the coating liquid was prepared.

Application to the soft vinyl chloride sheet and determination of stains were conducted in accordance with Example 1.

Table 2 Example 3 (Surface coating method) A coating solution prepared by synthesizing the ethyl silicate as in Example 1 and adjusting it with methyl alcohol was applied uniformly to the surface of a plate glass, exposed outdoors for one year, and visually observed the degree of contamination. Judgment was made.

The test method and stain evaluation were based on Example 1.

Table 3 Example 4 (Surface Coating Method) Various alcohols listed in Table K below were used for the synthesis of alkyl silicate, and the coating liquid was prepared.

Application to the surface of a plate glass and determination of stains were conducted in accordance with Example 1.

Note to Table 4) Ethyl:isopropyl:lauryl silicates were mixed in a weight ratio of 1:t17:55 Example 5 (Kneading method) Using ethyl alcohol, the ethyl silicate obtained by method A was Thoroughly mix the sample according to the recipe,
The mixture was kneaded using a 16-inch test roll at 175° C. for 10 minutes to form a sheet with a thickness of 0.2 mm. This sheet was then exposed outdoors for one year, and the degree of staining was determined by visual pressure.

The test method and stain evaluation were based on Example 1. Also,
The S1 content (parts by weight) is the value calculated by converting the amount of Si in ethyl silicate to 100 parts by weight of vinyl chloride.

(Formulation) Hinyl chloride (polymerization [1500) 100 parts by weight Plasticizer DOP 45.01 TCP 7.0 1 Epoxidized soybean oil 2-OIBln liquid stabilizer (
LTL-! 101A) 5.0 z ゛ Ethyl silicate of the present application Predetermined amount (indication) No. 5
Table Example 6 (Kneading method) Various alcohols listed in the following table were used for the synthesis of alkyl silicate. Example 5 for kneading into vinyl chloride
In addition, the stain determination was conducted in accordance with Example 1.

Table 6 (note) Ethyl: inpropyl; lauryl silicates were mixed in a weight ratio of 1:t17:55.

Effects of the invention As seen in the results of Examples 1 to 6, when alkyl silicate was applied or kneaded.

In all cases, the products according to the invention exhibited excellent stain resistance.

Regarding the surface coating method, Example 1. As shown in Table 1, when the Si content in the coating liquid is 105~Q, 0005% by weight, the surface stain prevention effect - At IF te, I:, ru.

That is, when the Si content is 0.0005% or less (
In experiments 1 and 2), it is extremely impractical to have a dirty house after 2 months. Furthermore, when the Si content is higher than α05 weight (Experiment 7), the entire surface becomes white immediately after application, which significantly impairs the appearance. Therefore.

Practical solution concentration is 0.05 to α00 as S1 content
05 weight - is preferable.

Similar results apply to Example 5, Table 3.

Also, Example 2. In Table 2, there is a remarkable difference in the effect between the case where the first alcohol is used for the synthesis of the alkyl silicate and the case where the second alcohol is used for the synthesis of the alkyl silicate. That is, when using ethyl alcohol (Experiment 8) and when using secondary alcohol alone (Experiment 9.10)
There is also a noticeable difference in staining between the two cases (Experiment 11). In Experiment 8, the dirt index was 2 after 4 months.
However, in Experiment 9.10, the dirt reached 2 only after 9 months.

Therefore, the effects of primary alcohol and secondary alcohol cannot be ignored in practice.

Furthermore, secondary alcohol has a stain-preventing effect even when used in combination with other alcohols. That is, as seen in Experiment 11, the combined use of the first alcohol and the second alcohol is comparable to the performance when the second alcohol is used alone.

In the case of the kneading method, Example 5. As shown in Table 5, the S1 content relative to vinyl chloride.

When the amount is 01 to 0,005 parts by weight, the surface stain prevention effect is remarkable. That is, when the Si content is 0.0005 parts by weight or less (Experiment 25.24), staining after 2 months is extremely impractical. Also, the S1 content is 0
．． If it is more than 1 part by weight (Experiment 29), the kneaded sheet will completely devitrify, impeding transparency and significantly reducing the value of the molded product. Therefore, the practical S1 content is resin 1
It can be said that 0.1 to 0.00 parts by weight is preferably 0.1 to 0.00 parts by weight.

Also, Example 6. In Table 6, there is a remarkable difference in the effects when a primary alcohol is used for the synthesis of an alkyl silicate and when a secondary alcohol is used for the synthesis of an alkyl silicate.

That is, 9 cases using ethyl alcohol (Experiment 30)
There is a noticeable difference in staining between the two alcohols used alone (Experiments 51 and 52) or in combination (Experiment 53).

In Experiment 50, the dirt index reaches 2 after 4 months, but in Experiments 31 and 32, the dirt index reaches 2 only after 6 months. Therefore, the effects of the primary alcohol and the secondary alcohol cannot be ignored in practice.

Further, the secondary alcohol has a stain-preventing effect even when used in combination with other alcohols. That is, as shown in Experiment 33, the combined use of the first alcohol and the second alcohol is comparable to the performance when the second alcohol is used alone.

In both the surface application method and the kneading method, the alkyl silicate synthesized using secondary alcohol is more effective in preventing stains than 17A/coal.

Claims (6)

[Claims] (1) Si content on the surface of the molded product is 0.05 to 0.00
0.5% by weight, diluted with a solvent, carbon number 2-1
A method for preventing surface stains on molded products, which comprises uniformly applying the alkyl silicate of No. 8 and then drying it. (2) The method for preventing surface stains according to claim 1, wherein the alkyl group of the alkyl silicate is a secondary alkyl group. (3) Claims 1 and 2, characterized in that the alkyl silicate is a mixture of two or more types of alkyl silicate, at least one of which is an alkyl silicate having a secondary alkyl group. Section 2. Surface stain prevention method. (4) The number of carbon atoms is 2 to 100 parts by weight of thermoplastic resin.
18 alkyl silicate with Si content of 0.1~
A method for preventing surface staining of thermoplastic resin molded products, characterized by kneading 0.0005 parts by weight. (5) The method for preventing surface stains according to claim 4, wherein the alkyl group of the alkyl silicate is a secondary alkyl group. (6) Claims 4 and 5, characterized in that the alkyl silicate is a mixture of two or more types of alkyl silicate, at least one of which is an alkyl silicate having a secondary alkyl group. Section 5: Surface stain prevention method.