CS268116B1 - Oxidant-proof durable plastic composition - Google Patents

Abstract

Composition suitable for sealing machine parts and apparatus intended for the production and processing of combustion initiators and oxygen. It concerns in particular the sealing of contact surfaces of divided machine housings, divided containers, flanged pipe joints and spindles of closing organs. The sealing composition contains 46 to 98 X by weight of polytetrafluoroethylene, 1 to 40 X polyhydric inorganic acids and up to 53 X by total weight of the active surface-active agent including added fillers.

Description

The invention relates to an oxidant-resistant sealing composition suitable for washing surfaces of machine parts, technological and other apparatuses which are exposed to oxidizing substances or work with combustion initiators.

Known, permanently plastic oxidizing-resistant sealants produced from unbaked polytetrafluoroethylene contain either liquid additives of halogen derivatives or transiently liquid solutions of inorganic salts. The compositions are formed into profiles, strands, foils and layers according to the arrangement of the sealed members.

The disadvantages of compositions which contain halogenated derivatives are, on the one hand, in their to-.

and on the one hand in the specific odor of irritating mucous membranes of handling persons.

Compositions that contain solutions of inorganic salts are less plastic and change their consistency depending on storage conditions.

These disadvantages are eliminated by the oxidant-resistant sealing composition according to the invention, which consists of a homogeneous mixture of 46 to 98% by weight, polytetrafluoroethylene, 1 to 40% by weight, polybasic inorganic acids or mixtures of acids optionally diluted with suitable volatile solvents. The composition is supplemented by up to 53% of the total weight of a non-flammable inorganic filler with an active surface, eg white soot, diatomaceous earth, ground glass frit, etc., including color pigments stable in an oxidizing environment.

The advantage of the composition according to the invention is in particular the possibility of its use in the environment of oxygen gas or other oxidizing agents in a wide range of operating temperatures from -60 ° C to + 180 ° C. The content of free polybasic inorganic acids is also suitable both for their passivating effects on the surfaces of ferrous components and for enhancing the plasticity of the composition when sealing apparatuses made of brittle material, e.g. glass.

The sealing composition is permanently plastic and thus suitable for sealing the contact surfaces of machine housings, flange connections and spindles of closing members used in the production and processing of oxygen or other oxidizing media.

The sealing composition according to the invention consists essentially of three basic components which, at room temperature, do not chemically react with each other in a highly plastic state. Polytetrafluoroethylene common to all of the following examples of blends allows the composition to be formed into the required profiles or shapes without molding technology adversely affecting the sealing properties.

Example 1; Composition suitable for forming into a profile 4 2.5 mm used to seal the dividing planes of the oxygen turbocharger housing with an internal working overpressure of 4 MPa component: polytetrafluoroethylene 65 X wt.

component: trihydrophosphoric acid 30 X wt.

component: silica 2 X wt.

component: ground colored glass 3 X wt.

Example 2: Composition for sealing rings of oxygen pipe flanges component: polytetrafluoroethylene 56 X wt.

component: pyrophosphoric acid solution in alcohol or ether 10 X wt.

3-component: bentonite 34 X wt.

EíllilžÉ-ž ^: Composition for sealing flanges of glass apparatus suitable for application by gravel

CS 268116 01 component: polytetrafluoroethylene component: sulfuric acid component: silica% wt.

% wt.

X wt.

Claims (1)

OBJECT OF THE INVENTION Permanently plastic composition resistant to oxidants, for the contact surfaces of machine parts and apparatus which are located in an oxidizing environment or which work with combustion initiators, especially for the contact surfaces of machine cabinets, flanged joints and fittings, consisting of a solid component which is organic fluoropolyer, from a liquid component for increasing the plasticity of the composition and for the function of the lubricant in forming sealing profiles or in self-sealing and for possible passivation of the surface of related metal parts and further from active substance or mixture of these substances or filler, that the liquid component to achieve the desired plasticity is an inorganic polybasic acid reacting with the surface of the sealed metal parts, the ratio being such that the composition contains 46 to 98% by weight of polytetrafluoroethylene, 1 to 40% of polybasic inorganic acid or mixtures thereof. 53 X total weight of inorganic substances is surface, stable in a voiding environment, including any fillers.