RU2486215C1 - Heat-shield material - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to heat-shield materials based on heat-resistant ethylene-propylene diene rubber, which can be used in aircraft and rocket production. The heat-shield material based on ethylene-propylene diene rubber, which contains a vulcanising group, filler and process additives, further contains a modifying additive - polyvinylidene chloride or adamantane.

EFFECT: low rate of heating of the heat-shield material based on ethylene-propylene diene rubber.

3 tbl, 9 ex

Description

The invention relates to heat-protective materials based on heat-resistant ethylene propylene diene rubbers that can be used in aircraft and rocket science.

Known heat-protective material AR-998 (TU 38.1051211-83), which is a composition comprising a reinforcing heat-resistant filler made of asbestos fabric with a double-sided lining with a rubber mixture based on synthetic ethylene propylene diene rubber.

A significant drawback of this material is that asbestos fabric has a higher coefficient of thermal conductivity than the rubber mixture, which in turn leads to an increase in the heating rate of the heat-shielding material and, as a consequence, to a decrease in its heat-shielding characteristics.

The closest is the heat-shielding material (Pat. 2404209 RF, IPC C08L 23/16, B32V 25/10, F16L 59/00, F02K 9/34, November 20, 2010) made of a formed layer of aramid fiber of a non-woven structure, laid between two layers of the rubber mixture brand 51-2110 (TU 38.10551177-88) based on ethylene propylene diene rubber with subsequent vulcanization as part of the product.

The disadvantage of this heat-shielding material is that during its operation, the rubber layer is destroyed and the substance is carried away from the surface of the heat-shielding material, which, in turn, leads to an increase in the heating rate of the heat-shielding material, a decrease in its heat-shielding characteristics, and a decrease in the service life of the product or unit in whole.

Thus, the known compositions do not allow to obtain materials with a high level of heat-shielding characteristics, which reduces their consumer and operational qualities.

The task of the invention is to obtain materials with high thermal characteristics.

The technical result of the claimed invention is to reduce the heating rate of a heat-shielding material based on ethylene propylene diene rubber while preserving the physico-mechanical and thermophysical characteristics at the level of the prototype.

The technical result is achieved in that the heat-shielding material based on ethylene propylene diene rubber, including a vulcanizing group, a filler and processing aids, additionally contains a modifying additive, polyvinylidene chloride or adamantane, in the following ratio, wt.h .:

Rubber SKEPT one hundred Sulfur 2.0 Dithiodimorpholine 1,5 Tiuram D 0.75 Altax 0.5 Zinc oxide 5,0 Stearin 1,0 Triethanolamine 2.0 Carbon black 2.0 Inden-Coumarone Resin 10.0 Pine Rosin 3.0 White soot 10-30 Specified Modifier 5-25

The essence of the invention lies in the fact that during the operation of the heat-shielding material, polyvinylidene chloride (or adamantane) is ablated, which occurs in the temperature range 150-200 ° C (for polyvinylidene chloride) or 150-300 ° C (for adamantane) with an endothermic effect. As a result of ablation, firstly, the thermal load on the heat-shielding material is reduced, since the process proceeds with an endothermic effect. Secondly, gaseous ablation products create a heat-insulating layer between the flame jet and the surface of the heat-shielding material. As a result of these two processes, the destruction of the rubber layer slows down, which, in turn, leads to a decrease in the heating rate of the heat-shielding material and an increase in its heat-shielding characteristics and, as a result, an increase in the service life of the product or unit as a whole.

The following components are used in the proposed material:

SKEPT-50 ethylene propylene diene rubber containing dicyclopentadiene dicyclopentadiene (TU 2294-022-05766801-2002) as a diene copolymer.

Vulcanizing group:

vulcanizing agents - sulfur (GOST 127-76), dithiodimorpholine (TU 2478-033-05807983-2002);

vulcanization accelerators - thiuram D (TU 6-14-943-79), altax (TU 6-14-851-86);

vulcanization activators - zinc oxide (GOST 202-84), stearin (GOST 6484-96), triethanolamine (TU 6-09-2448-91).

Filler - white soot BS-120 (GOST 18307-78).

As technological additives, inden-coumaron resin (TU 14-6-72-89), pine rosin (GOST 19113-84) and carbon black K-354 (GOST 7885-86) are used.

Polyvinylidene chloride (TU 2212-015-00203275-2003) or adamantane (TU 6-02-7-39-87) is used as a modifying additive.

Samples of heat-protective material based on ethylene propylene diene rubber are tested according to GOST 270-75 “Rubber. Method for determination of tensile strength properties ", GOST 263-75" Rubber. Shore A Hardness Test Method, GOST 267-73 Rubber. Methods for determining the density ", GOST 23630.2-79" Plastics. Method for determining thermal conductivity. "

The rate of heating of the heat-shielding material during high-temperature heating was estimated using a special device consisting of a base with a metal cup fixed to it with a water jacket and a gas-air burner. A sample of heat-shielding material, made in the form of a cylinder with a diameter of 30 mm and a height of 20 mm, was fixed in a glass and one of its surfaces was heated with a burner flame for 150 seconds. Using thermocouples embedded in the sample, the temperature inside the sample was determined as it was heated. The distance from the junction of the thermocouple to the heated surface was 5 mm. The rate of heating of the sample material was estimated from the time from the start of heating to reaching a temperature of 100 ° C in a layer with a thermocouple.

A heat-protective material based on ethylene propylene diene rubber, including a curing group, a filler, processing and modifying additives, is obtained in the following way. The manufacture of the rubber compound is carried out on rollers, for example, type LB 450 225/225. The mixing process on the rollers at the stage of preparing the rubber for mixing (dissolution) and the introduction of the ingredients is carried out for a period of at least 20 minutes. The input mode of the ingredients is presented in table 1. The vulcanization of the rubber mixture is carried out at a temperature of 150 ° C for 60 minutes. Then, the obtained samples are subjected to the necessary tests.

The invention is illustrated by the following examples:

Example 1. Prepare a rubber mixture of composition 1 (table 2). The mixture of rubber ingredients is produced on rollers LB 450 225/225. The input mode of the ingredients is presented in table 1. Then from the prepared rubber mixtures cured samples providing the appropriate tests. The vulcanization of the rubber mixture is carried out at a temperature of 150 ° C for 60 minutes. Physico-mechanical, thermophysical and heat-shielding properties of the proposed heat-shielding material are given in table 3.

Table 1 The mode of preparation of rubber compounds Technological operation Operation start time after the first boot, min Loading and dissolving rubber 0 Loading technological additives 5 Loading filler and modifying additive 8 Vulcanizing group loading eighteen Rubber compound removal twenty

The rubber mixtures according to examples 2-9 and the rubber mixture of the brand 51-2110 of the prototype, the compositions of which are given in table 2, are prepared analogously to example 1. Physico-mechanical, thermal and heat-shielding properties of rubber of the brand 51-2110 of the prototype and heat-shielding material according to examples 2-9 are given in table 3.

As can be seen from the data presented, the proposed heat-shielding materials, firstly, have a set of physicomechanical indicators comparable with the level of physicomechanical indicators of rubber grade 51-2110 of the prototype (with the exception of example 6). Secondly, the thermophysical characteristics of heat-shielding materials according to examples 1-9 are at the level of thermophysical properties of rubber of the brand 51-2110 of the prototype. Thirdly, the heat-shielding properties of the proposed materials, estimated by the time of heating to a temperature of 100 ° C (with the exception of examples 3, 6), are 10-20% higher than rubber grades 51-2110. The heat-shielding properties of the materials according to examples 1, 4, 9 are at the level of the prototype, which allows us to establish the optimal content of the modifying additive (for polyvinylidene chloride 5-25 parts by weight, for adamantane 5-15 parts by weight).

table 2 The compositions of the examples Names of components, parts by weight by examples Prototype (rubber brand 51-2110) one 2 3 four 5 6 7 8 9 Rubber SKEPT-50 one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred Sulfur 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Dithiodimorpholine 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 1,5 Tiuram D 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 Altax 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Zinc oxide 5,0 5,0 5,0 5,0 5,0 5,0 5,0 5,0 5,0 5,0 Stearin 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 1,0 Triethanolamine 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Carbon black K-354 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Inden-Coumarone Resin 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 Pine Rosin 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 White soot BS-120 10 thirty 10 thirty twenty 10 thirty twenty thirty thirty Polyvinylidene chloride 5 5 25 25 fifteen - - - - - Adamantan - - - - - 5 5 10 fifteen -

Table 3 Properties of heat-shielding materials Prototype (rubber brand 51-2110) by examples Names of indicators one 2 3 four 5 6 7 8 9 Conditional tensile strength, MPa 9.0 4.8 9.6 6.5 7.0 5.7 1.7 9.0 4.8 6.5 Elongation at break,% 420 770 830 690 510 940 240 670 650 600 Residual strain after rupture,% 25 33 thirty 60 twenty 65 0 16 42 thirty Shore A hardness, arb. 61 48 52 57 52 55 61 53 42 51 Density, kg / m ³ 1090 1160 1240 1130 1120 1210 1260 1160 1160 1150 The coefficient of thermal conductivity, W / (m · K) 0.23 0.20 0.23 0.19 0.22 0.21 0.20 0.23 0.21 0.22 Warming up time to a temperature of 100 ° C, s 122 127 144 115 126 134 121 146 137 128

Thus, the above information indicates the fulfillment of the following set of conditions when using the claimed invention:

теплозащитный материал на основе этиленпропилендиенового каучука, включающий вулканизующую группу, наполнитель, технологические добавки и модифицирующую добавку поливинилиденхлорид или адамантан, воплощающий заявленное изобретение при его осуществлении, обеспечивает повышение теплозащитных характеристик композиции за счет снижения скорости прогрева теплозащитного материала; $$$$

a heat-protective material based on ethylene-propylene diene rubber, including a vulcanizing group, a filler, processing aids and a modifying additive, polyvinylidene chloride or adamantane, embodying the claimed invention in its implementation, improves the heat-shielding characteristics of the composition by reducing the heating rate of the heat-shielding material;

the claimed invention allows to obtain heat-protective materials based on ethylene propylene diene rubber for use in aviation and rocket technology;

for the claimed invention, in the form described in the independent clause of the claims below, the possibility of its implementation using the means and methods described above or known prior to the priority date is confirmed;

means embodying the claimed invention in its implementation, is able to ensure the achievement of the perceived by the applicant technical result.

Therefore, the claimed invention meets the requirement of "industrial applicability" under applicable law.

Claims (1)

A heat-protective material based on ethylene-propylene diene rubber, including a curing group, a filler and processing aids, characterized in that it further comprises a modifying additive polyvinylidene chloride or adamantane in the following ratio of components, parts by weight:
Rubber SKEPT one hundred Sulfur 2.0 Dithiodimorpholine 1,5 Tiuram D 0.75 Altax 0.5 Zinc oxide 5,0 Stearin 1,0 Triethanolamine 2.0 Carbon black 2.0 Inden-Coumarone Resin 10.0 Pine Rosin 3.0 White soot 10-30 Specified Modifier 5-25