RU2220169C2 - Heat-shielding polymeric material and method for its preparing - Google Patents

Abstract

FIELD: polymers. SUBSTANCE: invention describes heat-shielding polymeric material comprising inorganic filling agent and polymeric matrix based on organosilicon block-copolymer and cross-linking agent wherein heat-shielding polymeric material comprises organosilicon block-copolymer as polymeric matrix of the general formula: OH{(C₆H₅SiO_1.5)_m[(CH₃)₂SiO]_n}H wherein m = 5-10; n = 15-25 in the following ratio of components, mass p. p.: inorganic filling agent, 17-56; organosilicon block-copolymer, 20- 60; tin diethylcaprylate, 1-4; oligoorganosiloxane, 10-30. Method for making heat-shielding polymeric material involves impregnation of inorganic solvent with polymeric matrix, drying, thermal treatment at temperature 50-80 C. Invention provides reducing density value and hardening temperature of heat-shielding material and possibility for its exploitation below temperature 400 C. EFFECT: improved preparing method, valuable properties of material. 4 cl, 2 tbl, 6 ex

Description

The invention relates to polymeric materials based on an organosilicon binder for thermal protection of aircraft products, rocket engineering, mechanical engineering and other equipment that can be operated up to a temperature of 400 ^o C.

Known heat-protective polymer material of the following composition, wt. hours:
SKTN-A polydimethylsiloxane rubber - 100
Ethylsilicate ETS-40 - 40
Ethylsiloxane oligomer PES-5 - 10
Tin diethyl dicaprylate - 1
Titanium Diboride or Aluminum Nitride Powder - 90 per 10 polymer binder
(RF patent 2165945)
A method of manufacturing a polymer material includes impregnation of fillers, drying and heat treatment of the material at a temperature of 900 ^o C for 30 minutes.

 The disadvantages of this material are high curing temperature and high density.

The closest analogue taken as a prototype is a heat-protective polymer material, including an inorganic filler and a polymer matrix based on an organosilicon resin and a crosslinking agent, characterized in that it contains an organosilicon block copolymer of the general formula
{Q _{x / 2} (C ₆ H ₅ ) ₃ SiO [Si (CH ₃ ) ₂ O] _n i (C ₆ Y ₅ ) ₃ O _{x / 2} } (C ₆ H ₅ SiO _1,5 ) _m
where x = 2-3;
n is 5-40;
m = 5-40,
in the following ratio of components, wt. hours:
Organosilicon block copolymer - 3-45
Crosslinking agent - 0.25-2.25
Inorganic Filler - 55-97
As an inorganic filler, a powder selected from the group consisting of beryllium oxide, silicon nitride, boron nitride, aluminum nitride or a mixture thereof can be used (RF patent 2129135).

A method of manufacturing a heat-resistant polymeric material includes impregnation of an inorganic filler with a polymer matrix with a crosslinking agent, drying, hot pressing and heat treatment at T = 260-400 ^o C.

 The disadvantages of the heat-protective material of the prototype and the method of its manufacture are high curing temperature and high density.

 An object of the invention is to reduce the density and curing temperature of the heat-protective polymer material.

The stated technical problem is achieved by the fact that the proposed heat-protective polymer material made of a composition comprising an inorganic filler and a polymer matrix based on an organosilicon block copolymer and a crosslinking agent, characterized in that the material contains an organosilicon block copolymer of the general formula
OH {[C ₆ H ₅ SiO _1,5 ] _m [(CH ₃ ) ₂ SiO] _n } H,
where m = 5-10;
n = 15-25,
and as a crosslinking agent, tin diethyl dicaprylate and oligoorganosiloxane in the following ratio of components, wt. hours:
Inorganic filler - 17-56
Organosilicon block copolymer - 20-60
Tin diethyl dicaprylate - 1-4
Oligoorganosiloxane (oligomethylphenylmethoxysiloxane) - 10-30
The heat-protective polymer material as an inorganic filler contains inorganic microspheres (from aluminoborosilicate, silica or quartz glass), expanded perlite, and polycrystalline alumina fibers or a mixture thereof.

Also proposed is a method of manufacturing a heat-protective polymer material, which consists in impregnating an inorganic filler with a polymer matrix based on an organosilicon block copolymer of the general formula
OH {[C ₆ H ₅ SiO _1,5 ] _m [(CH ₃ ) ₂ SiO] _n } N,
where m = 5-10;
n = 15-25,
followed by the introduction of a crosslinking agent consisting of tin diethyl dicaprylate and oligoorganosiloxane in the following ratio of components, wt. hours:
Inorganic filler - 17-56
Organosilicon block copolymer - 20-60
Tin diethyl dicaprylate - 1-4
Oligoorganosiloxane - 10-30,
and heat treatment of the obtained material at 50-80 ^o C.

 In the manufacture of a heat-protective polymer material, inorganic microspheres, expanded perlite and polycrystalline alumina fibers or a mixture thereof are used as an inorganic filler.

 The authors found that the proposed composition of the polymer matrix with the stated ratio of ingredients and the method of manufacturing the heat-shielding material can reduce the curing temperature of the heat-shielding polymeric material, and the use of inorganic microspheres, expanded perlite and polycrystalline alumina or a mixture thereof can reduce the density of the material.

Implementation example
Example 1. For the manufacture of heat-protective polymer material, a semi-finished product was first made by impregnating an inorganic filler with a polymer matrix without a crosslinking agent.

A crosslinking agent was added to the resulting mixture. A heat-shielding polymer material was applied to the prepared substrate from a fluoroplastic film, followed by heat treatment at 50-80 ^o C.

 The manufacturing technology of the heat-shielding material according to examples 2-6 is similar to example 1. The compositions of the proposed material and the prototype material are shown in table 1. Table 2 shows the data on the results of comparative tests of the set of characteristics obtained on the proposed composition of the heat-shielding polymer material and the prototype material.

From table 2 it is seen that the density of the proposed material is 2-4 times lower than that of the prototype material, and the curing temperature is reduced to 50-80 ^o C.

 Using the proposed heat-protective polymer material by reducing the density and curing temperature will reduce the mass of products, apply it to products of any configuration and reduce energy consumption in the manufacturing process of the material.

Claims (4)

1. Thermal protective polymer material made from a composition comprising an inorganic filler and a polymer matrix based on an organosilicon block copolymer and a crosslinking agent, characterized in that the material contains an organosilicon block copolymer of the general formula OH {[C ₆ H ₅ SiO _1,5 ] _m [(CH ₃ ) ₂ SiO] _n } H, where m = 5-10; n = 15-25, and as a crosslinking agent, tin diethyl dicaprylate and oligoorganosiloxane in the following ratio of components, parts by weight: Inorganic Filler 17-56 Organosilicon block copolymer 20-60 Tin diethyl dicaprylate 1-4 Oligoorganosiloxane 10-30 2. The material according to claim 1, characterized in that inorganic microspheres, expanded perlite and polycrystalline alumina fibers or a mixture thereof are used as an inorganic filler. 3. A method of manufacturing a heat-protective polymer material according to claims 1 and 2, which consists in impregnating an inorganic filler with a polymer matrix based on an organosilicon block copolymer of the general formula OH {[C ₆ H ₅ SiO _1,5 ] _m [(CH ₃ ) ₂ SiO] _n } H, where m = 5-10; n = 15-25, followed by the introduction of a crosslinking agent consisting of tin diethyl dicaprylate and oligoorganosiloxane, in the following ratio, wt.h: Inorganic Filler 17-56 Organosilicon block copolymer 20-60 Tin diethyl dicaprylate 1-4 Oligoorganosiloxane 10-30 and heat treatment of the obtained material at 50-80 ° C. 4. A method of manufacturing a heat-protective polymer material according to claim 3, characterized in that inorganic microspheres, expanded perlite and polycrystalline alumina fibers or a mixture thereof are used as an inorganic filler.

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