CS273221B1 - Composition for hydrosilylation curable polymer production - Google Patents

Abstract

A composition for hydrosilylation curable polymer production formed by polysiloxanes containing vinyl substituents, preferably in the form of dimethylvinylsiloxy, methylphenylvinylsiloxy, or methylvinylsiloxy groups, further cross-linking methyl(hydrogen)dimethyl siloxane copolymer, carbon blacks with increased electrical conduction, whose mass in the composition does not exceed 5 %, possibly containing a filler, preferably silicon oxide which, as a catalyst of hydrosilylation vulcanisation, contains complexes of rhodium, preferably dicyclooctadien-μ,μ'-dichloro-thiocyanogen complex, tetracarbonyl- μμ'-dichloro-thiocyanogen complex or tetracyclo-octene-μ,μ'-dichloro-thiocyanogen complex. The composition is prepared by mixing the two components A and B, of which both can contain the abovementioned components with the exception of methyl(hydrogen)dimethyl siloxane copolymer and a hydrosilylation catalyst, which are present only in one of the components A and B. The cured polymers are particularly suitable as a second protective layer for passivation of electrotechnical components.

Description

A composition for the production of a hydrosilylating vulcanizable polymer consisting of polysiloxanes containing vinyl substituents, preferably in the form of dimethylvinylsiloxy-, methylphenylvinylsiloxy- or methylvinylsiloxy groups, and a sieving methyl (hydrogen) dimethylsiloxane copolymer, optionally containing preferably silica which contains rhodium complexes as the hydrosilylation vulcanization catalyst, preferably dicyclooctadiene (γ, γ-dichloride), tetracarbonyl (γ), ich-dichlorodifluoride complex, or terracyclooctenten (,) -dichlorodioxide complex. The composition is prepared by mixing two components A and B, both of which may contain the above components except the methyl (hydrogen) dimethylsiloxane copolymer and the hydrosilylation catalyst, which are present in only one of components A and B.

Vulcanized polymers are particularly suitable as a second protective layer for passivation of electrical components.

273 221 (11) B1 (51) Int. Cl. ⁵

OJ C 08 L 83/07

CS 273 221 B1

The invention relates to a composition for the manufacture of a hydrosilylation-curable polymer for the passivation of electrical components.

In technical practice, passive electrical components are used because the hole and electron transition of power silicon semiconductor elements is exposed to the outside (oxygen, humidity, etc.). Therefore, various recombination centers may be formed on their surface, and thus the equilibrium transition state may be disturbed, causing instability of the electrical parameters of the semiconductor devices.

Therefore, these components are protected by polymers of high purity and high specific electrical resistance. A disadvantage of these polymers is their susceptibility to being easily charged by surface charges. Therefore, a solution in the form of a two-layer protection has been proposed in which the passivation layer of high surface resistivity is covered by a second passivation layer with a specific surface resistance in the range of 1.10 to 1.10 _.

The realization of this solution is hampered by the fact that the prior art silicone polymers based on so-called cold one- or two-component silicone rubbers filled with electro-conductive carbon black are not very suitable for this purpose, since curing residues can adversely affect the electrical properties of the passivated component.

Addition silicone polymers, although satisfactory in terms of purity, of their platinum-based cure catalysts, fail in the presence of a plurality of electroconductive carbon blacks. These drawbacks are solved by the invention, which is based on a composition for the production of a hydrosilylation-vulcanizable polymer for the passivation of electrotechnical components, consisting of polysiloxanes containing vinyl substituents, preferably in the form of dimethylvinylsiloxy, methylphenylvinylsiloxy, a conductivity of not more than 5% in the composition, optionally containing a filler, preferably silica which contains rhodium complexes as the hydrosilylation curing catalyst, preferably dicyclooctadiene, [beta] -dichlorodirodium complex, tetracarbonyl-yu, [beta] -dichlorodirodium complex, or tetracycllookten- [U, yu] -dichlorodirodium complex. This composition can be prepared by mixing two components A and B, both of which may contain the above components except the methyl (hydrogen) dimethylsiloxane copolymer and the hydrosilylation catalyst, which are present in only one of components A and B.

The composition of the invention has a long pot life of uncured 3m 3 · 3 at room temperature and usually does not need to be extended by adding inhibitor. The vulcanization is usually carried out at temperatures above 100 ° C, preferably above 120 ° C, but higher temperatures can also be used. The vulcanization time depends on both the catalyst concentration and the vulcanization temperature and is usually chosen within a few minutes to several hours. The vulcanizate has advantageous mechanical properties and according to the quality and the proportion of electroconductive carbon black can be selected its surface resistivity in the range of 1.10 to 1.10 ^ ^ 2 Λ_, preferably 1.10 to 1.10 ^{11 8} her.

All the ingredients required for the preparation of these compositions are readily available, since both the vinyl-containing polysiloxanes and the cross-linking methyl (hydrogen) dimethyldisiloxane copolymer are produced for the preparation of hydrosilylation-crosslinked rubbers, fillers and electro-conductive carbon black are common commercial products and finally the complexes are substances used in organometallic chemistry and homogeneous coordination catalysis.

The following examples illustrate the invention without limiting or limiting it.

CS 273 221 B1

Example 1

A hydrosilylation-curable polymer composition comprising 100 parts of dimethyl vinyl siloxane terminated polyidyl methyl siloxane and having an average molecular weight of 2,3.10, 13 parts of a methyl (hydrogen) dimethylsiloxane copolymer having a hydrogen content in the form of Si-H bonds of 0.2 wt. 25 parts of modified branched polysiloxane formed by the acid-catalyzed reaction of branched etoxypolysiloxane and tetramethyldivinyldisiloxane, 7 parts of chemazorh carbon black with increased electrical conductivity and 1.10 parts of dioyclooctadiene, yu'-dichlorodirhodic complex were subjected to 155 volts after curing. black vulcanizate with no apparent defects of specific surface resistance 1.10 ^ 32. .

Example 2

A hydrosilylating vulcanizable polymer composition comprising 50 parts of methylphenylvinylsiloxy terminated polyidimethylsiloxane having a mean molecular weight of 5.10, 10 parts of a methyl (hydrogen) dimethylsiloxane copolymer having a hydrogen content of 0.6 wt. %, 10 parts silica, 0.2 parts carbon black

1.10 ³ parts of a tetracarhonyl-γu, γu'-dichlorodirodium complex was cured at 120 ° C for 25 h. A flexible elastomer with a smooth surface without vision was obtained.

Possible faults with specific surface resistance 1.10 1.10.

Example 3

Kqmposice hydrosilylation curable polymer comprising 100 parts of poly (di- methyl siloxane) endcapped dimetylvinylsiloxanovými moieties having average molecular weight of 4.10 ^3, 1 part of methyl vinyl dimetylsiloxanového copolymer, 5 parts of methyl (hydrogen) dimetylsiloxanového copolymer of the hydrogen content in, the form of Si-H bonds 0 1 wt. %, 2 parts of carbon black, and 2.1 parts of ³ parts of the tetracycllookten-yu, yu'-dichlorodirodium complex was vulcanized at 140 ° C for 5 h.

Q with a non-sticky surface without visible defects 3 with a specific surface resistance of 1.10 JL.

Claims (2)

SUBJECT OF THE INVENTION A composition for the production of a hydrosilylating vulcanizable polymer, consisting of polysiloxanes containing vinyl substituents, preferably in the form of dimethylvinylsiloxy-, methylphenylvinyl3iloxy- or methylvinylsiloxy groups, further comprising a sieving methyl (hydrogen) dimethylsiloxane copolymer having an optional water content of 5%. containing a filler, preferably silicon dioxide, characterized in that it contains rhodium complexes, preferably dicyclooctadiene-yu, yu'-dichlorodirodium complex, tetracarbonyl-yu, uu-dichlorodirodium complex, or tetracycloctenten-yu, yu-dichlorododioxide complex as the hydrosilylation vulcanization catalyst . 2. A composition according to claim 1, characterized in that it is divided into two components A and B, both of which may contain the aforementioned components except for the methyl (hydrogen) dimethylsiloxane copolymer and the hydrosilylation catalyst which are present in only one of the components A and B.