RO110243B1 - Rubber composition for antistatic and hard inflammable conveying belts plating on the nitrilic rubber basis - Google Patents

Abstract

The present invention relates to o composition for plating strips of transport, antistatic, highly flammable, based nitrile rubber and polybutadiene rubber.

Description

The present invention relates to a rubber composition, used in the manufacture of conveyor belts with textile insert, used in underground mining operations.

For the preparation of the conveyor belt with textile insertion, compositions having the part of polymers from combinations of nitrile, neoprene or methane rubber and polyalkylene glycol, alkyl phosphate and quaternary ammonium compounds and compositions for coating antistatic and hard flammable conveyor belts are known. containing chloroprene rubber and various fillers or compositions with polychloroprene rubber mixed with polybutadiene rubber.

Their disadvantage is an unsatisfactory workability, abrasion very close to the maximum permissible limit, a long duration of vulcanization, and to the gallery burning test at limit values.

The composition according to the invention removes the above disadvantages, in that it consists of polychloroprene rubber from 35 to 60 parts, nitrile rubber from 40 to 65 parts, polybutadiene rubber from 0 to 10 parts, so that the sum of the three polymers to be pure parts, black from active smoke from 30 to 60 parts, alumina from 25 to 50 parts, chloroparaffin K 71, obtained by chlorination of the paraffin fraction C 10-03 or of C7 -Cyl fatty alcohols, with 70% chlorine content from 15 to 30 parts, 0-3 to 15 parts stub trioxide, 5 to 15 parts medium aromatic oil (Teleajen), phenyl-iza-naphthyl-amine antioxidant or

N-isopropi-1 N'-phenyl-p-phenylenediamine from 0.5 to 2 parts, fatty acids or stearin from 1 to 2 parts, magnesium oxide 4 parts, zinc oxide from 3 to 5 parts , tetramethylthiuram monosulfide from 0.6 to 1 parts, diphenyl guanidine from 0.8 to 1.2 parts, sulfur from 1 to 1.5 parts, the parts being expressed by weight.

The composition according to the invention has the following advantages:

- very good workability in the mixer, rollers and calender;

- a very good abrasion, values below 150 mm cubes;

- very good behavior at the firing sample in the gallery;

- faster vulcanization is ensured.

The following is an example of making the composition according to the invention.

Weigh the following components: polychloroprene rubber 50 kg, nitrile rubber 55 kg, polybutadiene rubber 11 kg, active smoke black 45 kg, alumina 47 kg, chlorparaffin K 71 25 kg, styrene trioxide 6 kg, medium aromatic oil (celery) 10 kg , antioxidant phenylheia-naphthyl- amine or N-isopropyl- N'-phenyl-pphenylenediamine 2.3 kg fatty acids or stearin

1.7 kg, magnesium oxide 4.7 kg, zinc oxide

5.8 kg, tetramethylthiuram monosulfide 0.9 kg, diphenyl guanidine 0.9 kg, sulfur 1.4 kg.

The mixture is run in a mixer of

2301.

The physico-chemical characteristics of the composition according to the invention are shown in table 1.

Table 1

Characteristic Values imposed Values obtained Verification method 1. Breaking resistance, N / mm, min 15 17 STAS 3884-84 2. Elongation at break,% min 400 400 STAS 3884-84 3. Abrasion resistance, mm, max two hundred 150 STAS 6699-89 4. Resistance to accelerated aging in the oven: - variation of breaking resistance,% max - losses from elongation at break,% max - losses from adherence% max 25 25 25 24 24 25 STAS 5152-82 168hx70 C 5. Surface electrical resistance, ohms, max 3x10 3x10 STAS 8917-71

Tables 2 and 3 show the characteristics imposed on the mining bands and to which the rubber mixture subject to the invention must also correspond.

Table 2

Flame behavior

Characteristic Conditions of admissibility Verification method 1. testing in a free atmosphere Duration of flame persistence: - the sum for each group of 6 samples, s, max - for each test, s, max Flame recurrence 45 15 the flame should not reappear after the air flow is applied STAS 8893-86 2. burning test in the gallery - the appearance of the specimens after the exposure to burning in the gallery: To remain intact a portion of tape at least 25 cm and the length equal to the width of the specimen

Table 3 friction test on the drum

Characteristic Conditions of admissibility Verification method - the appearance of the flame during the test in the quiet atmosphere, and respectively in the current of Not allowed STAS 12775- air 89 - the occurrence and release of incandescent particles during the test or at Not allowed finally, in a quiet atmosphere and respectively in the air flow: - temperature of the surface of the drum during the test and at the end, ° C, max 300

Claim 15

Claims (1)

Rubber composition for coating flammable and hard flammable bands, based on nitrile rubber, characterized in that it consists of 20 polychloroprene rubber from 35 to 60 parts, nitrile rubber from 40 to 65 parts, polybutadiene rubber from 0 to 10 parts, so that the sum of the three polymers is fielOO parts, active smoke black from 30 to 60 25 parts, alumina from 25 to 50 parts, chlorparafine K 71 from 15 to 30 parts, trioxide from 0 to 15 parts, medium aromatic oil (Teleajen) from 5 to 15 parts, antioxidant phenyl-heftz-naphthyl, amine or N-isopropyl- N'-phenyl-p-phenylenediamine from 0.5 up to 2 parts, fatty acids or stearin from 1 to 2 parts, magnesium oxide 4 parts, zinc oxide from 3 to 5 parts, tetramethylthiuram monosulfide from 0.6 to 1 parts, diphen-1 guanidine to 0.8 to 1.2 parts, sulfur to 1 up to 1.5 parts, the parts being expressed by weight.