JP3126394B2 - Solvent for crosslinked and cured silicone rubber composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dissolving agent which uniformly dissolves and decomposes a crosslinked and cured silicone rubber molded product, and more particularly to a silicone rubber gel-like crosslinked and cured product adhered or adhered on various materials. It relates to a dissolving agent that is dissolved and removed.

[0002]

2. Description of the Related Art As a method for dissolving and decomposing a crosslinked and cured silicone rubber composition, there are known a method of decomposing with a strong alkaline aqueous solution such as potassium hydroxide and a method of decomposing with an amine compound such as tetramethylguanidine or ethylenediamine. However, in the former method, a heating device is required to decompose by heating in a strong alkali, and there is a tendency that there is an operational danger due to heating of a strongly alkaline substance.

[0003] The latter method of decomposing with an amine compound can be carried out even at room temperature, but requires a high concentration of the amine compound and requires a long time for dissolution and decomposition. Further, both are alkaline compounds, and particularly when the silicone rubber composition bonded and molded to a metal material having a high ionization tendency such as aluminum or zinc is peeled and dissolved, etc., these metal materials are corroded and dissolved by the alkaline compound. In many cases, there is no effective peeling / dissolving method.

The greatest disadvantage of these decomposers known in the prior art is that, in particular, a silanol-terminated organopolysiloxane is subjected to a condensation crosslinking reaction curing with an organotrialkoxysilane or tetraalkoxysilane.
It is effective in dissolving and decomposing a so-called condensation type crosslinked silicone rubber composition, but a millable reaction type in which vinyl groups directly bonded to Si atoms or a vinyl group and a methyl group directly bonded to Si atoms are crosslinked and cured using a peroxide as a catalyst. It is not possible to dissolve and decompose silicone rubber compositions or addition-reaction-type silicone rubber compositions in which vinyl groups and hydrogen groups directly bonded to Si atoms are cross-linked and cured using a platinum compound as a catalyst. The fact is that the dissolution and decomposition of the silicone rubber composition has not been developed yet.

[0005]

Therefore, in the present invention,
In order to overcome the drawbacks of the prior art, it is possible to uniformly dissolve a silicone rubber composition crosslinked and cured by various types of reaction at room temperature in a short time, and to remove metals having high ionization tendency such as aluminum and zinc. It is an object of the present invention to provide a novel dissolvable composition of a silicone rubber molded product which does not easily cause corrosion.

[0006]

That SUMMARY OF THE INVENTION The present invention is charcoal
Hydrogen, halogenated hydrocarbon, ketone, organic acid ester
An organic solvent having a property of swelling at least one kind of crosslinked and cured silicone rubber selected from the group consisting of trihalogenated acetic acid and / or trihalogenated acetic anhydride;
Substance, trihalogenated acetyl chloride, trihalogenated
At least one selected from the group consisting of ethyl acetate
It comprises a dissolving agent for uniformly dissolving a crosslinked and cured silicone rubber composition essentially consisting of a kind of trihalogenated acetic acid derivative compound.

The organic solvent having a property of swelling the crosslinked and cured silicone rubber used in the present invention has a property of effectively swelling and decomposing the crosslinked silicone rubber composition, and dissolves the decomposed product uniformly. It is selected from those that have such properties.

As a solvent having such properties, a compound comprising at least one organic solvent selected from the group consisting of hydrocarbons, halogenated hydrocarbons, ketones and organic acid esters is used. Examples thereof include hydrocarbons such as benzene, toluene, xylene and white gasoline, halogenated hydrocarbons such as trichloroethane, ketones such as methyl ethyl ketone and cyclohexanone, and organic acid esters such as butyl acetate.

An important component which effectively dissolves and decomposes a silicone rubber molded article in combination with an organic solvent which swells the crosslinked and cured silicone rubber composition is trihalogenated acetic acid and / or a derivative thereof. Almost all kinds of organic carboxylic acids were tested. As a result, trihalogenated acetic acid and / or its derivative compound was used in combination with the above-mentioned organic solvent to effectively dissolve and decompose the silicone rubber molded product that was effectively cured by various curing reaction mechanisms. The present invention was completed because it was found to have the property. Of course, it was found that the silicone rubber molded product could be uniformly dissolved and decomposed by using only the trihalogenated acetic acid and / or its derivative compound. However, this compound has a serious smoke emission due to water absorption and has a difficulty in handling. The present invention has been completed by using in combination with an organic solvent.

The amount of the trihalogenated acetic acid and / or a derivative thereof used in combination with the organic solvent is not particularly limited depending on the type of the organic solvent and the degree of crosslinking of the silicone rubber molded product to be dissolved. Usually, about 2.5 to 30% by weight of trihalogenated acetic acid and / or a derivative thereof is preferable to the above-mentioned organic solvent.

The silicone rubber molded product in which the dissolving agent of the present invention can be dissolved is an addition type silicone rubber molded product in which a vinyl group directly bonded to a silicon atom and a hydrogen group are cross-linked by addition reaction with a platinum compound catalyst or the like. Millable silicone rubber molded products in which vinyl groups directly bonded to each other, or a vinyl group and a methyl group are crosslinked by a catalyst such as peroxide, and silanol hydroxyl groups directly bonded to silicon atoms such as alkoxysilane, oximesilane, aminoxysilane, etc. Any curing reaction mechanism such as a condensation-type silicone rubber molded article which is cross-linked and cured by a condensation reaction reagent may be used, and all of them can be uniformly dissolved in a relatively short time at room temperature. Further, a silicone resin composition, a silicone grease composition and the like can be dissolved.

In order to enhance the decomposition and dissolution effect of the novel uniform dissolving agent for silicone rubber molded articles according to the present invention,
Surfactants such as anionic surfactants and nonionic surfactants, and highly polar solvents such as dimethylformamide and dimethylsulfoxide can be used in combination, and furthermore, dyes, pigments, flow regulators for imparting thixotropic properties, etc. Can be used in combination.

As described above, since the solubilizer obtained by the present invention contains, as a main component, an organic weak acid such as trihalogenated acetic acid and / or a derivative thereof, the silicone rubber composition adhered to various metal surfaces can be used. Since peeling and dissolution can be performed without causing corrosion, it can be used very effectively, and uniform dissolution of the molded silicone rubber can be achieved only by immersion at room temperature. Specific examples of the trihalogenated acetic acid used in the present invention include trifluoroacetic acid, trichloroacetic acid, and tribromoacetic acid. As the trihalogenated acetic acid derivative compound used in the present invention, trihalogenated acetic anhydride, for example, trifluoroacetic anhydride, trihalogenated acetyl chloride, for example, trifluoroacetyl chloride, trihalogenated acetic acid ethyl ester, for example, trifluoroacetic acid Ethyl acetate and the like can be mentioned. Incidentally, trihalogenated acetic acid and its derivative compound can be used alone, respectively,
They can be used together.

Further, since the cured silicone rubber composition, which has been conventionally disposed of by embedding or incineration, is uniformly dissolved in a solvent, it can be reused as an effective silicone rubber composition. Thus, it is believed that the cured silicone rubber composition as waste can be reused as a useful resource, and can contribute to a wide range of industries.

[0015]

The present invention will be described below with reference to examples and comparative examples. Example 1 20 g of a millable reaction-curable silicone rubber cured piece cut by a combination of 100 parts by weight of trichloroethane and 5 parts by weight of trifluoroacetic acid (manufactured by Shin-Etsu Chemical Co., Ltd.)
KE860) was observed to dissolve after immersion at 20 ° C. for 48 hours. The results are shown in Table 1.

Example 2 The same test as in Example 1 was performed using trichloroacetic acid instead of trifluoroacetic acid. The results are shown in Table 1.

Comparative Examples 1 to 5 Instead of trifluoroacetic acid, monochloroacetic acid, formic acid,
The same test as in Example 1 was performed using acetic acid, propionic acid or phenoxyacetic acid. The results are shown in Table 1.

[0018]

[Table 1]

Example 3 Example 1 using xylene instead of trichloroethane
The same test was performed. The results are shown in Table 2.

Example 4 A test similar to that of Example 3 was performed using trichloroacetic acid instead of trifluoroacetic acid. The results are shown in Table 2.

Comparative Examples 6 to 10 Instead of trifluoroacetic acid, monochloroacetic acid, formic acid,
The same test as in Example 3 was performed using acetic acid, propionic acid or phenoxyacetic acid. The results are shown in Table 2.

[0022]

[Table 2]

Example 5 By combining 90 parts by weight of toluene, 10 parts by weight of methyl ethyl ketone and 5 parts by weight of trifluoroacetic acid,
20 g of the shredded condensation reaction type silicone rubber cured piece (KE20RTV manufactured by Shin-Etsu Chemical Co., Ltd.) was immersed at 20 ° C. for 72 hours to observe the tendency to dissolve. Table 3 shows the results.

Example 6 A test similar to that of Example 5 was performed using trichloroacetic acid instead of trifluoroacetic acid. Table 3 shows the results.

Comparative Examples 11 to 15 Instead of trifluoroacetic acid, monochloroacetic acid, formic acid,
The same test as in Example 5 was performed using acetic acid, phenoxyacetic acid or xylenoxyacetic acid. Table 3 shows the results.

[0026]

[Table 3]

Example 7 An addition-type curable silicone shredded with a combination of 90 parts by weight of toluene, 10 parts by weight of butyl acetate, 0.5 parts by weight of a nonionic surfactant, and 7 parts by weight of trifluoroacetic acid. 20 g of a cured piece of rubber (TSE340RTV manufactured by Toshiba Silicone Co., Ltd.) was immersed in the heat at 70 ° C. for 4 hours.
Dissolution tendency was observed. Table 4 shows the results.

Example 8 A test similar to that of Example 7 was performed using trichloroacetic acid instead of trifluoroacetic acid. Table 4 shows the results.

Comparative Examples 16 to 20 Instead of trifluoroacetic acid, monochloroacetic acid, formic acid,
The same test as in Example 7 was performed using acetic acid, chlorphenoxyacetic acid or xylenoxyacetic acid. Table 4 shows the results.

[0030]

[Table 4]

Example 9 A solution 1 was prepared by combining 90 parts by weight of xylene, 5 parts by weight of dimethylformamide, and 5 parts by weight of trifluoroacetic acid.
Fine fragments 10 of a completely cured deacetic acid type RTV silicone rubber (KE42 manufactured by Shin-Etsu Chemical Co., Ltd.) per 100 g
g and immersion at 20 ° C. for 24 hours, the dissolution tendency of the silicone rubber was observed. Table 5 shows the results.

Example 10 A test similar to that of Example 9 was performed using trifluoroacetic anhydride instead of trifluoroacetic acid. Table 5 shows the results.
It was shown to.

Example 11 The same test as in Example 9 was performed using trichloroacetic acid instead of trifluoroacetic acid. Table 5 shows the results.

Example 12 The same test as in Example 9 was performed using tribromoacetic acid instead of trifluoroacetic acid. Table 5 shows the results.

Comparative Examples 21 to 26 Instead of trifluoroacetic acid, monochloroacetic acid, formic acid,
The same test as in Example 9 was performed using acetic acid, acetic acid cloid, phenoxyacetic acid or xylenoxyacetic acid. Table 5 shows the results.

[0036]

[Table 5]

Example 13 80 parts by weight of xylene, 20 parts by weight of butyl acetate, 5 parts by weight of trifluoroacetic acid, and 1 part by weight of trifluoroacetyl chloride were combined to obtain a cured silicone rubber and silicone resin per 100 g of solution. 15 g of the mixed glass cloth tape adhesive was added, immersed in heat at 50 ° C., and the dissolution tendency of the silicone compound was observed after 48 hours. Table 6 shows the results.

Example 14 A test similar to that of Example 13 was carried out using ethyl trifluoroacetate instead of trifluoroacetyl chloride. Table 6 shows the results.

Example 15 The same test as in Example 13 was carried out using 6 parts by weight of trichloroacetic acid instead of the combination of trifluoroacetic acid and trifluoroacetyl chloride and the combination of trifluoroacetic acid and ethyl trifluoroacetate. Was. Table 6 shows the results.

Comparative Examples 27-31 Instead of the combination of trifluoroacetic acid and trifluoroacetyl chloride and the combination of trifluoroacetic acid and ethyl trifluoroacetate, dichloroacetic acid, monochloroacetic acid, formic acid, acetic acid or chlorphenoxyacetic acid 6 The same test as in Example 13 was performed using parts by weight. Table 6 shows the results.

[0041]

[Table 6]

[0042]

As described above, according to the present invention, it is possible to dissolve a silicone composition crosslinked and cured at room temperature by various reaction modes in a short time and uniformly, and to dissolve aluminum, zinc or the like. This has a great effect that corrosion does not easily occur even for metals having a high ionization tendency.

Claims (1)

(57) [Claims] 1. Hydrocarbon, halogenated hydrocarbon, keto
At least one selected from the group consisting of organic acid esters
An organic solvent having the property of swelling a kind of crosslinked and cured silicone rubber, and trihalogenated acetic acid and / or trihalide.
Logenated acetic anhydride, trihalogenated acetyl chloride
From the group consisting of
A dissolving agent for uniformly dissolving a crosslinked and cured silicone rubber composition essentially consisting of at least one selected trihalogenated acetic acid derivative compound.