RU2500047C1 - Electroconductive peroxide cross-linkable composition - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: electroconductive peroxide cross-linkable composition comprises, wt %: polyolefin 49-62, benzopropionic acid 3,5-bis(1,1-dimethylethyl)-4-hydroxy-2-[3-[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]-1-oxopropyl] hydrazide -0.05-0.20, tetra-bis-methylene-(3-(3,5-di-tret-butyl-4-hydroxyphenyl) propionate)-0.05-0.20, organic peroxide-0.2-1.9, electroconductive technical carbon with specific volume resistance p=10±6 Ohm*cm - 29-34, technical carbon with specific volume resistance p=5±3 Ohm*cm - 2.5-5, 4,4'-thiabis(6-tret-butyl-m-cresol) - 0.05-0.25, zinc stearate - 0.15-1.0, polyethylene wax - 3-9. The composition of the specified compound is not exposed to substantial thermal-oxidative ageing and premature cross-linking during superimposition, and items from it have smooth surface.

EFFECT: improved physical and mechanical properties of cable products made with application of the proposed composition, and its manufacturability and stability.

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Description

The invention relates to the field of electrical engineering, namely cable technology, and can be used for screens of power cables of medium voltage up to 35 kV.

The production of medium-voltage power cables (6-35 kV) in recent years has tended to displace paper-impregnated cables with polymer-insulated cables.

The design of such cables provides for the presence of three layers superimposed on a conductive core - an electrically conductive polymer screen, polymer insulation and a second electrically conductive polymer screen.

The presence of an electrically conductive screen is due to the need to create an equipotential surface designed to significantly reduce the likelihood of breakdown of insulation in a certain area of space, where the electric field strength in the absence of such a screen could be excessively high.

Known electrical insulation composition (RF patent No. 2394292 "Electrical insulation composition", publ. 07/10/2010) containing a copolymer of ethylene with vinyl acetate, aluminum hydroxide (Al (OH) ₃ or magnesium Mg (OH) ₂ , additionally contains high density polyethylene modified with maleic anhydride, polyethylene wax, nanoclay, 3,5-ditret-butyl-4-hydroxy-phenylpropionic acid ester and pentaerythritol (Irganox 1010) or 1,3,5-trimethyl-2,4,6-tris (3,5-di tert-butyl-4-hydroxybenzyl) benzene (Irganox 1330), benzo-propionic acid 3,5-bis (1,1-dimethiethyl) -4-hydrox and-2- [3- [3,5-bis (1,1-dimethyethyl) -4-hydroxyphenyl] -1-oxopropyl] hydrazide (Irganox MD 1024) in the following ratio, wt.h .:

Ethylene Vinyl Acetate Copolymer 60-85 Aluminum or magnesium hydroxide 130-170 High density polyethylene, modified with maleic anhydride 15-35 Polyethylene wax 0.1-5 Ether of 3,5-di-tert-butyl-4-hydroxy-phenylpropionic acids and pentaerythritol - Irganox 1010 or 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4- hydroxybenzyl) benzene - Irganox 1330 0.05-0.7 Benzopropionic acid 3,5-bis (1,1-dimethiethyl) -4- hydroxy-2- [3- [3,5-bis (1,1-dimethyethyl) -4-hydroxyphenyl] -1-oxopropyl] hydrazide - Irganox MD 1024 0.05-0.3 Nanoclay 10-20

A disadvantage of the known composition is the insufficient value of strength and elongation at break.

Known crosslinkable electrical insulation composition (RF patent No. 2440633 "Electrical insulating crosslinkable composition", publ. 01/20/2012), including polyolefin, vinyltrimethoxysilane or vinyltriethoxysilane, organic peroxide and a crosslinking catalyst, contains synergists - tetra-bis-methylene- (3- (3 5-di-tert-butyl-4-hydroxyphenyl) propionate, benzo-propionic acid 3,5-bis (1,1-dimethylethyl) -4-hydroxy-2- [3- [3,5-bis (1,1 -dimethylethyl) -4-hydroxyphenyl] -1-oxopropyl] hydrazide and poly - [[6 - [(1,1,3,3-tetramethyl-4-piperidinyl) imino] -1,6-hexanediyl [(2 , 2,6,6-tetramethyl-4-piperidinyl) im foreign]]) in the following ratio of components, wt.%:

Vinyltrimethoxysilane or Vinyltriethoxysilane 1.0-3.0 Organic peroxide 0.1-0.4 Tetra bis-methylene- (3- (3,5-di-tert-butyl- -4-hydroxyphenyl) propionate 0.05-0.3 Benzopropionic acid 3,5-bis (1,1- dimethylethyl) - -4-hydroxy-2- [3- [3,5-bis (1,1-dimethiethyl) -4- -hydroxyphenyl] -1-oxopropyl] hydrazide 0.1-0.5 Poly - [[6 - [(1,1,3,3-tetramethyl-4- piperidinyl) imino] -1,6-hexanediyl [(2,2,6,6-tetramethyl-4- piperidinyl) imino]]) 0.1-5.0 Crosslinking Catalyst 0.05-1.0 Polyolefin rest

This polymer composition has insulating properties, while weak electrically conductive properties are required to create equipotential surfaces. The tensile strength does not reach the values required for the shields of medium-voltage cables.

The disadvantages of the known crosslinkable electrical insulating composition, therefore, include insufficiently high mechanical strength and the inability to use as an electrically conductive screen.

The task was to develop an electrically conductive composition of peroxide crosslinking, which will improve the reliability of electrical networks and reduce the cost of their maintenance and maintenance when switching to medium-voltage cables with cross-linked polyethylene insulation.

The polymer composition should be suitable for processing on existing production lines of cable plants, have high mechanical properties, have a specific volume resistance sufficient for low electrical conductivity, have a smooth surface, have good adhesion to other materials, not undergo significant thermal oxidative aging and premature cross-linking when applied . As a conductive filler, a material should be used that will ensure optimal physical properties of the final composition. Such a filler should be commercially available and inexpensive.

The technical result is achieved in that the electrically conductive peroxide crosslinkable composition comprising a polyolefin, benzopropionic acid 3,5-bis (1,1-dimethylethyl) -4-hydroxy-2- [3- [3,5-bis (1,1-dimethiethyl) -4-hydroxyphenyl] -1-oxopropyl] hydrazide, tetra-bis-methylene- (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), organic peroxide, additionally contains a conductive carbon black with a specific volume resistance when the content in the polymer ρ = 10 ± 6 Ohm * cm, carbon black with a specific volume resistance when contained in the polymer ρ = 5 ± 3 ohm * cm, 4,4'-tiabis (6-tert-butyl-m-cresol), zinc stearate, polyethylene wax, wt.%:

Polyolefin 49-62 Carbon black with specific volume resistance at the content in the polymer ρ = 10 ± 6 Ohm * cm 29-34 Carbon black with specific volume resistance at the content in the polymer ρ = 5 ± 3 Ohm * cm 2,5-5 4,4'-thiabis (6-tert-butyl-m-cresol) 0.05-0.25 Tetra bis-methylene- (3- (3,5-di-tert-butyl-4- hydroxyphenyl) propionate) 0.05-0.20 3,5-bis (1,1-dimethylethyl) -4-hydroxy- benzopropionic acid 2- [3- [3,5-bis (1,1-dimethiethyl) -4-hydroxyphenyl] -1- oxopropyl] hydrazide 0.05-0.20 Zinc stearate 0.15-1.0 Organic peroxide 0.2-1.9 Polyethylene wax 3-9

According to the invention, it is necessary to use a polyolefin, for example, ethylene vinyl acetate or high pressure polyethylene, as the polymer base. Such polymers are produced both by Russian and foreign industry.

Organic peroxide is used as a crosslinking initiator; some types of such compounds (for example, dicumyl peroxide) are produced by Russian industry. The produced peroxides provide the required high and stable quality of crosslinking of the material.

Carbon black of two types used as a filler provides the polymer with the required value of specific volume resistance (<100 Ohm * cm at 23 ° С). It should be noted that the electrically conductive properties of carbon black are determined at different filling in the polymer. The first carbon black should provide a specific volume resistance of ρ = 10 ± 6 Ohm * cm at 35% content in the polymer, and the second with the same content - ρ = 5 ± 3 Ohm * cm.

Carbon black with such characteristics is produced by domestic industry.

Zinc stearate, used as a lubricant in the processing of materials, is also produced by Russian industry.

Polyethylene wax is produced in the CIS, it is necessary as an external lubricating component.

These three types of antioxidants are used to prevent undesirable chemical processes and material destruction both during production and processing, as well as during further operation as part of cables. Materials are known and mass-produced by the chemical industry of the countries of the world.

The invention is illustrated by the following example.

Table 1 Composition Components, wt.% No. 1 Number 2 Number 3 No. 4 (famous) Polyolefin 50,4 54,4 60 93.95 Carbon black (ρ = 10 ± 6 Ohm * cm) 36.1 31.1 24.4 - Carbon black (ρ = 5 ± 3 Ohm * cm) 4.1 5.18 7.06 - 4,4'-thiabis (6-tert-butyl-m-cresol) 0.09 0.13 0.13 - tetra-bis-methylene- (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate) 0,07 0.06 0.06 0.1 benzopropionic acid 3,5-bis (1,1-dimethylethyl) -4-hydroxy-2- [3- [3,5-bis (1,1-dimethiethyl) -4-hydroxyphenyl] -1-oxopropyl] hydrazide 0.1 0.1 0.1 0.5 Zinc stearate 0.24 0.26 0.25 - Polyethylene wax 7.9 7.77 7 - Organic peroxide 1,0 1,0 1,0 2.0

table 2 Song Properties Name of parameters No. 1 Number 2 Number 3 No. 4 (famous) Thermal strain,% 65 25 51 60 Tensile strength, MPa 18.1 20.9 19.7 14.2 Elongation at break,% 212 276.6 255.4 650 Change in physico-mechanical parameters after heat aging at 135 ° C for 168 h, tensile strength,% 7.7 4.4 6.3 8 Change in physico-mechanical parameters after heat aging at 135 ° C for 168 h, tensile strength,% 5.1 2,5 4.4 12 The surface quality of the extrudable sample The surface is flat, smooth The surface is flat, smooth The surface is flat, smooth The surface is flat, smooth Volume resistivity at a temperature of 20 ° C (requires <100 Ohm * cm) 6.9 11.6 9.1 ≥100 (insulator)

These ranges of component content should be considered optimal. It is within these limits that the best quality of the composition is achieved both in terms of physical properties and in terms of their stability and reproducibility (see table No. 2).

The proposed conductive peroxide crosslinkable composition is suitable for processing on existing production lines of cable plants.

Compared to analogs, the electrically conductive peroxide-crosslinkable composition has high mechanical properties and a sufficient value of specific volume resistance for the poor conductivity of cable shields, good adhesion to other materials, it does not undergo significant thermo-oxidative aging and premature cross-linking when applied, and also has a smooth surface.

The proposed electrically conductive peroxide-crosslinkable composition used as a conductive filler allows to provide optimal physical properties of the final composition and is technologically advanced and inexpensive.

In general, the use of the proposed electrically conductive peroxide-crosslinkable composition in the production of medium voltage cables with cross-linked polyethylene insulation will significantly increase the reliability of electric networks and reduce the cost of their maintenance and maintenance.

Claims (1)

An electrically conductive peroxide crosslinkable composition comprising a polyolefin of benzopropionic acid 3,5-bis (1,1-dimethylethyl) -4-hydroxy -2- [3- [3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] - 1-oxopropyl] hydrazide, tetra-bis-methylene- (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), an organic peroxide, characterized in that it further comprises an electrically conductive carbon black with a specific volume resistance at the content in the polymer ρ = 10 ± 6 Ohm · cm, carbon black with a specific volume resistance when the content in the polymer ρ = 5 ± 3 Ohm · cm, 4,4'-thiabi s (6-tert-butyl-m-cresol), zinc stearate, polyethylene wax, with the following components, wt.%:
polyolefin 49-62 volumetric carbon black resistance ρ = 10 ± Ohm · cm 29-34 volumetric carbon black resistance ρ = 5 ± 3 Ohm · cm 2,5-5 4,4'-thiabis (6-tert-butyl-m-cresol) 0.05-0.25 tetra-bis-methylene- (3- (3,5-di-tert-butyl-4- hydroxyphenyl) propionate) 0.05-0.20 benzopropionic acid 3,5-bis (1,1-dimethylethyl) - 4-hydroxy-2- [3- [3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] - 1-oxopropyl] hydrazide 0.05-0.20 zinc stearate 0.15-1.0 organic peroxide 0.2-1.9 polyethylene wax 3-9