RU2688738C1 - Sealing padding material - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to chemical industry, in particular to production of Sealing padding materials – paronites, and can be used in chemical, petrochemical, automotive, shipbuilding and other industries of national economy for sealing of flat fixed surfaces, during operation of which the material is exposed to variable thermal and mechanical loads, as well as to action of organic oils and fuel at high temperatures. Sealing padding material includes several matched layers of polymer composite, matrix of which is made from rubber vulcanisate. Composition contains: butadiene-nitrile rubber, dispersed (powdery) and fibrous fillers. Besides, the composition of the polymer composite additionally exceeds 100 wt%, an organoboron polymer of the class of polymethylene ethers of phenols and boric acid is introduced.

EFFECT: invention increases specific breaking strength, sealing capacity of the sealing material, thermal stability and fungicidal properties, reduces swelling capacity of the sealing material in organic oils and fuels.

1 cl, 2 tbl

Description

The present invention relates to the chemical industry, in particular to sealing gasket materials based on rubbers and mineral fillers, which are designed to provide the required tightness in sealing assemblies with flat fixed sealing surfaces, during operation of which the gasket materials are subjected to chemical, thermal and mechanical loads, exposure to aggressive media (organic oils, gasolines, acids, alkalis, solvents, etc.).

Due to the high rates of industrial development, there is a tightening of requirements for sealing gasket materials that can work when interacting with aggressive media. Currently, Russian and foreign scientists are actively working to develop new materials that provide the required sealing capacity when exposed to chemical, thermal and mechanical loads. However, this is a very expensive and time-consuming process, so the issue of creating high-quality and cheap materials is important for both the manufacturer and the consumer. The proposed, less expensive and more effective, composition of the sealing material is a modification of already known materials with the improvement of individual characteristics.

Known sealing gasket material - paronite [1], comprising several layers of polymer composite with a polymer matrix of rubber vulcanizate, the content of which is 12.2 wt. %, the content of fillers - barite in the amount of 7.8 wt. % and asbestos in the amount of 80.0 wt. % Significant disadvantages of analogue are low strength properties, as well as the ability of the material to swell and partially decompose in organic oils and fuels, which leads to a restriction of its use, up to the impossibility of its use.

A known composition for the production of sheet materials intended for the manufacture of these sealing seals fixed flange connections [2]. The composition of the material includes a large number of different components: as a fibrous filler, basalt wool (8.0-10.0 wt.%), Aramid or polyoxadiazole fibers (13.0-15.0 wt.%) Are used; as dispersed fillers - vermiculite, chalk, kaolin, alumina; technological additives - carbon black, amine, colloidal silicic acid, polyvinyl alcohol. Significant disadvantages of the composition are the high cost, low sealing ability, as well as relatively low values of conventional strength at break sealing gasket material.

Another analogue of [3] is a laminated sealing material for gaskets (paronite), consisting of 22 layers (laminates), which are made of a polymer composite of the following composition: a matrix based on rubber (NK and SKI-3 or SKI-3 and SKMS-30ARK or SKS-30AKO) - 11-17 wt. %; dispersed fillers (minium, barite, kaolin, graphite, technical carbon) - 6-24 wt. %; fibrous filler (asbestos) up to 75 wt. % The disadvantages of this composition are low strength characteristics, as well as the ability of the material to swell in organic oils and fuels.

The authors of the technical solution of the patent [4] propose to use organic and / or inorganic asbestos-free inorganic fiber in the amount of 10 to 45 wt.% As a fibrous filler. % The disadvantage of this sealing material is high cost due to the use of expensive components, as well as poor resistance to corrosive environments.

The closest in technical essence and the achieved result can be called oil-resistant paronite [5, prototype], consisting of several combined layers of a polymer composite, the polymer matrix of which is made of nitrile rubber vulcanizate and its content in the composite is 15.0-18.0 wt. % The composition of the polymer matrix, in addition, introduced a liquid substance (ethyl acetate) that is not miscible with oil and gasoline, with a ratio of rubber vulcanizate and liquid substance 1.00: 0.03 ÷ 0.10. The dispersed filler is made of alumina and its content in the composite is 19.0-21.0 wt. % The fibrous filler is made of asbestos and its content in the composite is 60.0-63.0 wt. % Pigment (copper phthalocyanine), whose content in the composite is 0.2-0.4 wt. % and antioxidant in an amount of 0.1-0.6 wt. % Significant disadvantages of the prototype include: the use of copper phthalocyanine, which leads to the catalytic oxidation of hydrocarbons, which negatively affects the compacted metal surfaces, especially when water enters the densified medium; low thermal stability and the ability of the polymer matrix of paronite to swell in corrosive environments, which also dramatically reduces its performance characteristics, in particular, mechanical strength and oil and petrol resistance. The above drawbacks limit the possibility of widespread industrial use of this composition and necessitate the creation of a new composition with improved performance characteristics.

The problem to which the proposed technical solution is directed is: firstly, increasing the specific strength at break of the sealing material; secondly, an increase in the sealing ability of the gasket material; thirdly, an increase in thermal stability and fungicidal properties; fourth, reducing the possibility of swelling of the sealing material in organic oils and fuels.

The task is achieved by using for the first time as a modifier sealing gasket material, without changing the basic known technology of their manufacture, organoboron polymer belonging to the class of polymethylene esters of phenols and boric acid [6] of the following structure:

where n> 1.

The presence of a boron atom in the polymer structure increases the adhesion interaction of mineral fillers with a polymer matrix [7], increases the strength and thermomechanical characteristics of polymer compositions based on rubbers [8, 9], and also increases the thermal stability and fungicidal properties of materials based on elastomers and polyimides [10 , 11], which significantly expands the areas of application of modified gasket materials in areas with any climatic conditions. At the same time, the modified organo boric polymer sealing material has a low ability to swell in organic oils and fuels.

The proposed composition of the sealing gasket material includes: several layers of a polymer composite, a polymer matrix (its content may be in the range from 15.0 to 20.0 wt.%) Made of vulcanizate of nitrile-butadiene rubber plasticized with ethyl acetate; dispersed (powdered) filler - alumina 17.0 ÷ 20.0 wt. %; fibrous filler - asbestos 55.0 ÷ 65.0 wt. %; and additionally, in excess of 100 wt. %, introduced organoboron polymer class polymethylene esters of phenols and boric acid in the amount of 1.0 ÷ 5.0 wt. %

The proposed sealing gasket material was manufactured using a well-known standard paronite production technology on rollers with preliminary preparation of a paronite mass in a Z-shaped mixer without changing the main process procedure. Sealing gasket material contains 22 combined layers of polymer composite, the prescription of which is presented in Table 1.

The results of physico-mechanical tests of the prototype and the proposed composition (three options) are presented in table 2.

эфира борной кислоты), однако, введение борорганического полимера в состав полимерного композита снижает реологические характеристики материала в процессе его изготовления на паронитовых вальцах. Применение борорганического полимера в количестве более 5 мас. % не целесообразно, так как материал становится хрупким и не технологичным.Comparative analysis of the results of the data presented in table 2 shows that the most optimal from the point of view of physico-mechanical characteristics is example No. 3 (containing 5 wt.%

boric acid ester), however, the introduction of an organic boron polymer into the composition of the polymer composite reduces the rheological characteristics of the material during its manufacture on the paronite rollers. The use of organoboron polymer in the amount of more than 5 wt. % is not advisable, since the material becomes brittle and not technological.

The technical result is an increase in the density and conditional strength at break of the sealing material, a decrease in the ability of the material to swell under the action of organic oils and fuels, an increase in resistance to heat aging, an increase in the sealing ability, and an increase in the fungicidal properties of the material.

The proposed sealing gasket material was developed by the Department of Chemical Technology of energy-saturated materials and products of the engineering special department of the Biysk Technological Institute (branch) of the Altai State Technical University named after I.I. Polzunova. Sealing gasket material successfully passed all technological tests. Currently, the specified cushioning material proposed in industrial use as a sealing material of the flat fixed surfaces of the elements of technological devices.

Bibliography:

1. Poroshin, G.V. Paronite production / G.V. Poroshin, V.B. Novoseltseva. - M: Chemistry, 1978. - 72 p.

2. RF patent №2103308 dated 1/27/1998

3. RF patent №2227150 of 04/20/2004

4. JP patent No. 20020196714 of July 5, 2002

5. RF patent №2597922 dated 09/20/2016 (prototype)

6. RF patent №2318005 dated February 27, 2008

7. Korshak, V.V. Organ boric polymers / V.V. Korshak, V.A. Zamyatina, N.I. Bekasov. - M .: Science, 1975. - 255 p.

эфиром борной кислоты / Д.В. Корабельников, М.А. Ленский, М.С. Некрасов, Р.Н. Кондратьев, И.Е. Картавых // Пластические массы. - 2011. - №10. - С. 39-42.8. Korabelnikov, D.V. Increase in durability and wear resistance of friction composite materials by modification

ester of boric acid / D.V. Korabelnikov, M.A. Lensky, M.S. Nekrasov, R.N. Kondratyev, I.E. Burring // Plastics. - 2011. - №10. - pp. 39-42.

эфира борной кислоты в полимерных композиционных материалах на основе каучуков ч. III / Д.В. Корабельников, М.А. Ленский, А.В. Ожогин, А.С. Нартов, Е.С. Ананьева // Каучук и резина. - 2015. - №4. - С. 42-45.9. Korabelnikov, D.V. Study of the modifying effect of additives

boric acid ester in polymeric composite materials based on rubbers. Part III / D.V. Korabelnikov, M.A. Lensky, A.V. Ozhogin, A.S. Nartov, E.S. Ananeva // Rubber and rubber. - 2015. - №4. - pp. 42-45.

10. Grachek, V.I. Esters of boric acid - heat stabilizers and fungicidal additives of natural rubber elastomers / V.I. Grachek, A.N. Lukashik // FPA. - 2006. - T. 79. - №5. - p. 830-834.

11. Grachek, V.I. Thermal stabilization of polyimides with boric acid esters / V.I. Grachek, E.T. Krutko, L.Yu. Osmolovskaya, A.I. Globa // FPA. - 2011. - V. 84. - Vol. 9. - p. 1533-1536.

Claims (2)

Sealing gasket material comprising several combined layers of polymer composite, the polymer matrix of which is made of synthetic rubber vulcanized plasticized with ethyl acetate, containing dispersed (powdered) and fibrous fillers, characterized in that the polymethylene n-triphenyl ether of boric acid is introduced as a modifier, in the following ratio, wt. %: nitrile butadiene rubber 16,0 alumina 20.0 asbestos 64.0 polymethylene n-triphenyl ester of boric acid 1,0 ÷ 5,0 (in excess of 100 wt.% polymer composite)