Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Patent
1996-11-08
1999-03-23
Foelak, Morton
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
521 92, 521 93, 521122, 521123, 521124, 521134, 521154, C08J 908
Patent
active
058860606
DESCRIPTION:
BRIEF SUMMARY
This application is based on International Application PCT/RU96/00193, filed Jul. 16, 1996.
The present invention relates to the chemical technology, and in particular to the methods for obtaining the organosilicon compositions being foamed at the expense of gases liberated at chemical reactions of mixture components; the present invention may be used for production of elastomer foams having improved radiation resistance.
PRIOR AMOUNT
The methods for obtaining foamed organosilicon compositions are well known in the art (U.S. Pat. No. 5,238,967).
Such known methods involved obtaining foamed organosilicon compositions by means of mixing the polymer base, comprising the ".alpha.", ".omega."-dihydroxypolydiorganoisiloxanes and foaming agents.
The organosilicon composites obtained by means of the known method are consolidated at room temperature, yet featuring insufficient mechanical strength and thermal resistance.
Such other methods for obtaining hi-strength thermal resistive elastomer materials on the basis of block-copolymers having linear/ladder structure (see High Molecular Compositions, V. XXX, #9, Moscow, 1988, pp. 1832-1836).
Yet the known amount of art does not comprise any data on usage of block-copolymers having linear/ladder structure as a polymer base of foamed organosilicon compositions.
The most close to the present invention is the method for obtaining the foamed organosilicon compositions, involving the mixing of organosiloxane rubber, organosilicon joining agent and modifier (JP, A, 2-47158).
The known prior method involves usage of: vinyl containing poly organosiloxane as a organosiloxane rubber; polyorganohydridesiloxane with 0.3%-1.6% contents of SiH groups as a joining agent; and compositions containing hydroxyl groups as a modifier.
The known method provides to obtain the foamed organosilicon compositions having improved strength capacity. Yet the material produced according to the known method have high gassing rating at radiation exposure.
It is the basis of the present invention to resolve a problem to produce light weight and strong organosilicon material resistive to the long-term radiation exposure.
The technical result of the present Invention lies in decrease of radiation gassing of foamed organosilicon compositions, obtained by means of mixing of organosiloxane rubber, organosilicon joining agent and modifier.
To the accomplishment of foregoing technical result and related ends the present Invention, then, consists in that in the method for production of foamed organosilicon compositions, involving the mixing of organosiloxane rubber; organosilicon joining agent and modifier, the polyorganosiloxane block-copolymers are used as organosiloxane rubber, having general formula as follows: SiO!.sub.c }.sub.n, R.sup.3 R.sup.4 SiO monomeric units to R.sup.1 SiO.sub.1.5 falling within the range 0.850-10,000, correspondingly, where: R.sup.1 R.sup.2 R.sup.3 R.sup.4 are aliphatic, aromatic radicals having from 1 to 6 atoms carbon; n is an integer from 30 to 360; c=1; a is selected from the 0.019-3.760 interval; b is selected from the 0.008-0.240 interval; or the mixture of the above block-copolymer with the ".alpha.", ".omega."-dihydroxypolydiorganosiloxane in the ratio of (0.05-0.5); 1, respectively; while the individual compositions or mixtures of polyorganohydridesiloxanes act as organosilicon joining agent, having general formula as follows: (0.35-1.80)%; average numeric value of M molecular mass limited by 50-200, where: R, R.sup.1 is the lowest alkyl radical having from 1 to 6 atoms carbon; m is an integer from 1 to 20; n is an integer from 0 to 19; (m+n) sum equals 20, or at least one substance from the compositions having general formula as follows: --OH.dbd.C(CH.sub.3).sub.2, --OC(O)--CH.sub.3, follows: .dbd.CH.sub.3 --, C.sub.2 H.sub.5 --; n is an integer from 0 to 3, or the mixture of sodium bicarbonate with zinc oxide, or non-organic compound of cobalt with 34% cobalt content,
Various modifications may be made in performance of the method, provided the reasonable efforts are
REFERENCES:
patent: 3539530 (1970-11-01), Karstedt
patent: 4695597 (1987-09-01), Sejno
patent: 4705810 (1987-11-01), Millet
patent: 4987155 (1991-01-01), Inoue
patent: 5216037 (1993-06-01), Miyoshi
patent: 5238967 (1993-08-01), Okawa
patent: 5356940 (1994-10-01), Giesen
High Polymer Compositions By Svernyi V.Y. et al Published 1988 vol. 30.
Belyaev Spartak Timofeevich
Gulko Piter
Kozodaeva Marina Mikhailovna
Kozodaeva Natalia Mikhailovna
Makarenko Igor Anatol'evich
Foelak Morton
Garrison David L.
Marquardt Matthew J.
Obschestvennoe Ob'Edinente "Euro-Asian Physical Society"
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