SU817033A1 - Polymeric composition - Google Patents

Description

- The invention relates to polyethylene-based polymeric compositions capable of crosslinking in a microwave electromagnetic field (microwave electromagnetic field) used in the electrical industry for the insulation of wires and cables and in other products for electrical purposes. Polyethylene-based compositions are known in which various fillers are introduced to impart the ability to heat in a microwave electromagnetic field: metal powder l carbon black 2, which increases the dielectric loss in an electromagnetic field with a frequency of 2000-3000 MHz. When crosslinking polyethylene with organics, remove peroxides in the microwave electromagnetic field, a fast uniform heating is achieved over the entire volume of the product being stitched, with the exception of the appearance of undovulcanised and perevulcanized areas. The closest to the technical essence of the present invention is a polyethylene polymer composition based on carbon black (5-40 wt.%), Organic peroxide (2 wt.%) And antioxidant (0.3-0.5 wt.%) F3 . Effective dielectric heating of this composition is achieved with a carbon black content of 30 wt.% Or more. However, the introduction of a significant amount of carbon black reduces the electrical insulation and elastic properties of the composition (Table 2, examples 1, 2). The purpose of the invention is to improve the electrical insulation and elastic properties of the composition capable of crosslinking in a microwave electromagnetic field. To achieve this goal, a polymer xxlogy containing polyethylene, carbon black, a crosslinked peroxide-type agent and a stabilizer additionally contains a copolymer of ethylene with vinyl acetate (EVA) with 15–35 wt.% Vinyl acetate content or chlorinated polyethylene with 35–45 wt.% Chlorine. oligoether acrylate selected from the group consisting of tri (oxyethylene glycol; dimethacrylate (TGM-3), methacrylate diethylene glycol phthalate (MDF-1), methacryl glycol phthalate (MGF-1); 7 Carbon and soot 10-20

Ethylene copolymer

with vinyl acetate

or chlorinated

polyethylene 10-35 Crosslinking agent 1-2,5

Oligoether 1-2-5

Stabilizer Else

Carbon blacks PM-70, PM-50, etc. are used as the conductive filler.

Dicumyl peroxide, 1,3-di (tert-butylperoxyisopropyl) benzene (Percadox 14P) and other organic peroxides used for crosslinking polyolefins are used as a crosslinking agent.

N / N-di-p-naphthyl-p-phenylenediamine (diafene HH), dimethyl-bis- (p-phenylamino-phenoxy) sylane (product C-1), etc. are used as an antioxidant.

Examples 1-2. An antioxidant is injected into the melt of polyethylene on microforms at 130-140 seconds, carbon blacks and rolls under continuous cutting of the sheet for 20-25 minutes. At the end of mixing at 115-120 seconds organic peroxide is added and the mixing is continued for another 2-3 minutes.

Examples 3-4. Oligoester acrylate (Example 3) or a polar polymer (Example 4), an antioxidant, carbon black, and rolls with continuous cutting of the web for 20-25 minutes are introduced into the melt of polyethylene on the microvests at 13O-14 ° C. At the end of mixing at 115- 120c is introduced Organic Peroxide and continue mixing for another 2-3 minutes.

Examples 5-17. In melting of polyethylene in microweaves at 130140 ° C, a polar polymer (copolymer of ethylene with vinyl acetate or chlorinated polyethylene), Oligoether acrylate, an antioxidant, carbon black, and rolls are added with continuous cutting of the web for 2025 minutes. At the end of the blending, organic peroxide is introduced at 115 IZOC and the mixing is continued for another 2–3 minutes.

Test specimens are made from rolled strip

(without stitching) with the following mode: temperature 120С / specific pressure 40 kgf / cm, time 5 min.

The stitching of the compositions pressed in the indicated mode is carried out in. electromagnetic field frequency 20003000 MHz or by pressing in the following mode: temperature ,, specific pressure 40 kgf / cm, time 30 min.

Formulations of compositions are given in

Table 1, the properties of the compositions in Table 2.

Destructive stress during stretching and elongation at break are determined according to GOST 11262-76 on type A blades on an RMI-60 tensile machine at a speed of movement

5 movable clamp 500-50 mm / min.

The degree of crosslinking (gel fraction) is determined by the method of selective extraction of a non-crosslinked portion of the polymer with solvents such as xylene or decol LINE at the boiling point of the solvent.

Dielectric loss tangent and dielectric constant

5 at a frequency of 2450 MHz and 20 ° C is determined according to GOST 10404-63.

The specific volume resistivity is determined according to GOST 20214-74 on samples of size lOOtlO l mm.

The electrical strength at alternating voltage with a frequency of 50 Hz is determined according to GOST 6433-3-7 in transformer oil on samples with a diameter of 100 and a thickness of 1 mm.

From a comparison of the physicomechanical and electrical properties of the proposed compositions with the control ones (Table 2), it follows that partial replacement of carbon black with a mixture of polar polymer and oligoester acrylate is essentially

0 increases the specific volume electrical resistance and dielectric strength without a noticeable change in the tangent of dielectric loss angle and dielectric constant. it

Claims (1)

5 provides effective dielectric heating when stitching compositions in a microwave electromagnetic field and increases the relative elongation at break by 1.5-2 times. 9 81703 claims Polymer composition containing polyethylene carbon black. a peroxide-type peroxidizing agent and a stabilizer, characterized in that, in order to improve the electrical insulation and elastic properties. it additionally contains a copolymer of ethylene with vinyl acetate with a vinyl acetate content of 15-35 wt.% or chloro. rirovanny polyethylene with a chlorine content of 35-45 wt.% and oligozfirakrylat selected from the group, including three. Nrxyethylene glycol) dimethacrylate, methacrylate diethylene glycol phthalate, in the following ratio of components, wt.% 15 Polyethylene 49,7-67,7 Carbon black 10 -20 10 Vin-copolymer ethylene copolymer or chlorinated polyethylene 10-35 Crosslinking agent 1-2,5 Oligoether acrylate 1- 2.5 Stabilizer Else Sources of information taken into account during the examination 1. US patent 3393287, cl. 264-27, published. 1968. 2, US Patent 3551199, cl. 117-227, publication 1970. 3. Firsov Yu.I. Prodon G.P. Filled polyethylene compositions for crosslinking. - Plastics, 1978, No. 4, p.53 (prototype).