RU2321911C2 - Electric insulating composition - Google Patents

Abstract

FIELD: cable engineering.

SUBSTANCE: proposed smoke-emitting plasticized PVC based polymeric composition used for manufacturing insulation and cable sheaths has following ingredients, mass by part: suspension polyvinyl chloride, 100; ester plasticizer, 40-90; lead stabilizer, 2-8; antimony trioxide, 2-10; zinc oxide, 2-4; boron acid, 2-5; ocher, 10-70; calcium stearate, 1-3; diphenylolpropane, 0.1-0.4.

EFFECT: enhanced heat resistance of composition, its compliance with requirements to smoking under conditions of burning, smoldering, and hydrogen chloride emission in burning.

1 cl, 2 tbl

Description

The invention relates to cable technology, namely to polymer compositions based on plasticized polyvinyl chloride (PVC) with reduced combustibility, smoke emission under combustion and smoldering conditions and hydrogen chloride during combustion, designed to insulate the inner and outer shells of wires and cables in fire safety conditions.

Wires and cables often cause a fire and flame to spread. In this regard, their polymer components - insulation, inner and outer shells - traditionally had high demands on incombustibility. Recently, the requirements for fire safety characteristics have expanded significantly, in particular, to reduce the emission of corrosive gases during combustion, as well as smoke formation, which is a negative factor in the event of a fire in residential, domestic and industrial premises, both in flaming and flameless burning (decay).

In addition, the requirements for physical and mechanical characteristics and their preservation at a certain level in the conditions of operation of cable products in a wide temperature range are imposed on polymeric materials according to normative and technical documentation, which allows us to judge their reliability and service life.

To reduce the combustibility of PVC compositions, flame retardants, for example, antimony trioxide, are usually introduced into their composition, smoke absorbers, for example, carbonate fillers, to reduce smoke emission (Kodolov V.I. Retarders of the burning of polymeric materials. M .: Chemistry, 1980, pp. 7-25) .

To impart incombustibility and reduce smoke generation during the burning of plasticized PVC as a flame retardant, smoke suppressors are a combination of antimony trioxide, chlorinated paraffin, calcium carbonate and molybdenum oxide (US patent No. 4098748, 1978)

However, the degree of increase of incombustibility by the indicated means is not high.

A known PVC composition containing a combination of flame retardants-suppressants, including antimony trioxide, zinc oxide, boric acid, chalk and aluminum hydroxide (ed. Certificate of the USSR No. 1646278, 1995).

However, the level of reduction in smoke and hydrogen chloride during combustion is not high enough.

Also known is an electrical insulating composition containing polyvinyl chloride, an ester plasticizer, a lead stabilizer, antimony trioxide, zinc oxide, boric acid, calcium carbonate, aluminum oxide trihydrate and aerosil (ed. Certificate. USSR 1832700, 1996).

However, the level of reduction in the release of hydrogen chloride during combustion and smoke under conditions of combustion and decay is not high enough.

Closest to the proposed combination of known features is an insulating composition containing, by weight: suspension polyvinyl chloride 100, ester plasticizer 40-80, lead stabilizer 3-7, calcium carbonate 30-500, alumina trihydrate 10-100, antimony trioxide 4-7.5, zinc oxide 0.7-1.9, boric acid 0.4-0.6, ionol 0.1-0.6 and diphenylol propane 0.1-0.6 (US Pat. RF No. 2195729, 2001).

The specified composition meets the requirements for the level of smoke formation under conditions of combustion and decay and hydrogen chloride evolution during combustion, however, it has insufficiently high heat resistance, which reduces the life of cable products and limits the scope.

The task was to develop an insulating composition with high heat resistance while maintaining a low level of smoke during combustion and decay and the release of hydrogen chloride during combustion.

The technical result is achieved in that the electrical insulating composition containing suspension polyvinyl chloride, an ester plasticizer, a lead stabilizer, antimony trioxide, zinc oxide, boric acid, diphenylol propane, additionally contains ocher with a content of Fe ₂ O _{3 of} 12-15 wt.% And calcium stearate in the following the ratio of components, parts by weight: suspension polyvinyl chloride 100, ester plasticizer 40-90, lead stabilizer 2-8, antimony trioxide 2-10, zinc oxide 2-4, boric acid 2-5, ocher with a content of Fe ₂ O ₃ 12 -15 wt.% 10-70, s calcium tearate 1-3, diphenylolpropane 0.1-0.4.

The proposed composition may contain the following components: suspension polyvinyl chloride grade C70 according to GOST 14332-78, well-known ester plasticizers, such as dioctyl phthalate (DOP) and diisononyl phthalate (DINP) according to GOST 8728-77, dioctyl phthalates (DAP 789, DAP 810) according to GOST 8728 77, known lead stabilizers, such as tribasic lead sulfate (TOSS) according to TU 6-09-098-75, dibasic lead phthalate (DOPTS) according to TU 6-09-098-76, antimony trioxide (Sb ₂ O ₃ ) according to TU 6-09-3267-84, zinc oxide (ZnO) according to TU 48-7-17-82, boric acid (H ₃ VO ₃ ) according to GOST 18704-78, calcium stearate TU 6-09-4233-76, ocher T U 301-10-019-90 amended. No. 1. In addition to the listed components, the insulating composition may also contain other known target additives, in particular, dye concentrates in the dosages adopted for them.

Example: Suspended polyvinyl chloride, ester plasticizer, lead stabilizer, antimony trioxide, zinc oxide, boric acid, diphenylolpropane, ocher, calcium stearate are sequentially loaded into a working turbo mixer, sequentially, in the amounts prescribed by the formulation (table 1). After the temperature in the turbo mixer reaches 90 ° C, the mixture is discharged into a cooler, where it is cooled to 30 ° C, after which the mixture is extruded and granulated on an extruder at a temperature of 140 ° C-160 ° C.

Test samples are made from the obtained granulate. Heat resistance is determined in accordance with GOST 5960-72, the oxygen index (KI) is determined according to GOST 12.1.044-89, the maximum smoke density (Dm) under combustion and smoldering conditions is determined according to GOST 24632-81, the release of hydrogen chloride (L _HCl %) determined according to GOST R IEC 60754-1-99.

The composition of the composition according to the examples is shown in table 1, the properties are shown in table 2.

As follows from the data presented, the proposed electrical insulating composition has a higher heat resistance than the known one, with equal performance with it in terms of smoke generation during combustion and decay and hydrogen chloride evolution.

Table 1.
The composition of the polyvinyl chloride compositions (examples 1-8 according to the invention, 9-11 are comparative, 12 is a prototype) №№ one 2 3 four 5 6 7 8 9 10 eleven 12 prototype one 2 one. Suspension Polyvinyl Chloride one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred 2. Ester plasticizer 40 fifty 65 80 90 60 60 60 35 95 80 fifty 3. Lead stabilizer 2 four 6 8 four four 5 6 1,5 9 6 four four. Antimony trioxide 2 four 6 8 10 3 5 7 1,5 5 eleven 7 5. Zinc oxide 2 2 2 2 2 2 2 2 2 2 2 1.9 6. Boric acid 2 2 2 2 2 2 2 2 2 2 2 0.6 7. Ocher with a content of Fe ₂ O ₃ 12-15 wt.% 10 25 fifty 70 40 fifty 55 60 thirty 80 5 0 8. Calcium stearate one 1,5 2 3 2 2 2 2,5 one four 0.5 0 9. Chalk, CaCO ₃ 0 0 0 0 0 0 0 0 0 0 0 40 10. Aluminum trihydrate 0 0 0 0 0 0 0 0 0 0 0 60 eleven. Ionol 0 0 0 0 0 0 0 0 0 0 0 0.2 12. Definylolpropane 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3

Table 2.
Properties of polyvinyl chloride compositions (examples 1-8 according to the invention, 9-11 are comparative, 12 is a prototype) one 2 3 four 5 6 7 8 9 10 eleven 12 Preservation of the relative elongation of 7 days at 100 ° C,% 93 94 98 95 93 90 96 95 82 78 80 83 Dm - burning 210 202 204 198 212 206 205 209 208 207 208 205 Dm - smoldering 173 182 179 186 178 181 183 176 183 184 182 180 L _HCl % 9,4 9.2 9.3 9.3 9.6 9.2 9.2 9.1 8.9 9.2 9.2 9.1 KI,% 32,5 33.1 32.9 33.3 32.9 32.8 33,2 33.6 33.0 33.1 32.9 33

Claims (1)

An electrical insulating composition containing suspension polyvinyl chloride, an ester plasticizer, antimony trioxide, zinc oxide, boric acid, calcium stearate, diphenylol propane, characterized in that it additionally contains ocher containing 12-15 wt.% Fe ₂ O ₃ and calcium stearate in the following ratio of components wt.h .: Suspension Polyvinyl Chloride one hundred Ester plasticizer 40-90 Lead stabilizer 2-8 Antimony trioxide 2-10 Zinc oxide 2-4 Boric acid 2-5 Ocher with a content of Fe ₂ About ₃ 12-15 wt.% 10-70 Calcium stearate 1-3 Diphenylolpropane 0.1-0.4