RU2489459C1 - Polyvinyl chloride-based composition for insulation and sheaths of wires and cables - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to processing plastic, particularly polyvinyl chloride-based polymer compositions, which are used in various industries, including for making insulation and sheaths of wires and cables. The composition contains 100 pts.wt polyvinyl chloride, 40-80 pts.wt plasticiser, 3-15 pts.wt heat stabiliser and 0.1-8.0 pts.wt filler, which is chemically deposited calcium carbonate with surface treatment with fatty acids with particle size of 15-70 nm.

EFFECT: introduction of said filler into the polyvinyl chloride-based composition reduces viscosity of the molten composition and increases frost-resistance thereof while preserving physical and mechanical properties.

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Description

The invention relates to the field of plastics processing, in particular, to polymeric compositions based on polyvinyl chloride (PVC), which are used for the manufacture of insulation and shells of wires and cables.

The task was to develop a plasticized composition based on PVC, which has improved processability and high frost resistance while maintaining physical and mechanical properties.

Improvement of processability was evaluated by a decrease in melt viscosity and was characterized by a relative viscosity, which was calculated as the ratio of the viscosity of the filled composition to the unfilled.

The prototype of the invention is a polyvinyl chloride composition used in the cable industry, containing PVC, plasticizer, stabilizer and filler - white soot with a specific surface area of 20-40 m ² / g in an amount of 2-15 wt.h. per 100 parts by weight PVC (USSR Author's Certificate No. 469827, C08F 29/18, publ. 30.04.75). The introduction of white carbon black into the composition of a PVC composition reduces the melt viscosity of the composition while maintaining good physical and mechanical properties. The frost resistance of the plastic compound given in the copyright certificate is minus 55 - minus 60 ° C. According to the author’s certificate, the melt viscosity at 170 ° C is 1.25 · 10 ³ - 6.3 · 10 ² P. Reproduction of this composition and testing it according to the methods available to the authors showed that with the introduction of white carbon in the amount of 2-15 parts by weight per 100 parts by weight PVC, the relative viscosity of the composition is 0.74 - 0.87, and frost resistance decreases from minus 65 ° C to minus 45 - minus 60 ° C.

The aim of the invention is to reduce the melt viscosity of the plasticized composition based on PVC and increase its frost resistance while maintaining physical and mechanical properties.

To achieve this goal, a PVC-based composition, including a plasticizer, a heat stabilizer and a filler, as the last one contains chemically precipitated calcium carbonate with a surface treatment with fatty acids with a particle size of 15-70 nm in the following ratio of the components of the composition, parts by weight:

PVC one hundred Plasticizer 40-80 Thermal stabilizer 3-15 Chemically precipitated carbonate calcium with a particle size of 15-70 nm 0.1-8.0

As a chemically precipitated carbonate with a surface treatment with fatty acids, Socal 312 V (60 nm) (F. Solvay, Belgium), Shengke - 206 S (40-70 nm), Shengke - 206 T (40-70 nm), Shengke - 505 A (15-30 nm) (F. Shengda Tech Inc, China), Calcium carbonate nanoparticle (75-105 nm) from PlasmaChem Gmbh et al.

As a plasticizer, you can use dioctyl sebacinate (DOS), dioctyl phthalate (DOP), trioctyltrimellitate (TOTM), or mixtures thereof and others.

As a thermal stabilizer, tribasic lead sulfate (TOSS), dibasic lead phthalate (DOPTS), dibasic lead stearate (DOSS), etc. can be used.

The composition may additionally contain targeted additives, such as antioxidants, lubricants, stabilizers, flame retardants, pigments, etc.

For comparative tests on the prototype used white soot according to GOST 18307-78 brand BS-30 (60-108 nm).

The following are examples illustrating the invention.

Example No. 1

In a heated mixer of Henshel company with a volume of 10 l at a temperature of 40 ° C load 100 wt.h PVC, 5 wt.h. temperature stabilizer TOSS, 0.1 wt.h. chemically precipitated calcium carbonate Socal 312 V, with a particle size of 60 nm, is stirred to a temperature of 60 ° C for 15 minutes Then, 50 parts by weight are added to the mixer. plasticizer DOS and continue mixing the mixture to a temperature of 100 ° C for 15 minutes. Then the mixture was cooled to room temperature. The powder mixture is rolled on oil-heated rollers at a temperature of 165 ° C for 5 minutes. The obtained samples determine the frost resistance of plastic compounds in accordance with GOST 5960-72 on three samples with a size of 130 × 10 mm and a thickness of (1 ± 0.1) mm. The brittle temperature is taken to be the minimum temperature at which all samples maintained their integrity during bending by 180 °.

Tensile strength and elongation at break were determined according to GOST 11262-80 at a temperature of (20 ± 2) ° C.

The melt viscosity of the plastic compounds was determined using an Instron model 3211 capillary rheometer with a capillary diameter of 0.127 cm and a length of 2.55 cm at 165 ° C and a shear rate of 3.79 s ^-1 .

Relative viscosity (η _rel ) is calculated as the ratio of the viscosity of the filled composition (η _n ) to unfilled (η ₀ ):

$${\eta }_{\mathrm{about}tn}=\frac{{\eta }_n}{{\eta }_0}$$

The properties of the plastic are shown in the table.

Examples No. 2-11 (according to the invention)

The method of obtaining the composition and testing methods of plastic compounds in example 1. The composition and properties of the compositions are shown in the table.

Example No. 12 (based on the prototype - USSR copyright certificate No. 469827)

Examples No. 13-17 (prototype)

The method of obtaining the composition and testing methods of plastic compounds in example 1. The composition and properties of the compositions are shown in the table.

Examples No. 18-25 (for comparison)

The method of obtaining the composition and testing methods of plastic compounds in example 1. The composition and properties of the compositions are shown in the table.

From the data in the table it follows that the introduction into the composition of the claimed plasticized PVC composition of chemically precipitated calcium carbonate with a surface treatment with fatty acids with a particle size of 15-70 nm in an amount of 0.1-8.0 wt.h. per 100 parts by weight PVC can significantly reduce the melt viscosity of the composition (the relative melt viscosity is 0.48-0.71) and increase frost resistance, which is minus 50 ° C - minus 70 ° C. These indicators are significantly higher than the parameters of the prototype described in the description of the author's certificate of the USSR No. 468927, and obtained by reproducing this invention using 2-15 parts by weight of soot with a particle size of 60-108 nm. The relative viscosity of the melt according to the prototype is 0.71-0.87, and frost resistance minus 45 ° C - minus 60 ° C (see examples No. 1-11 in comparison with No. 12-17).

The table shows examples illustrating a decrease in melt viscosity and an increase in frost resistance with the introduction of nanoparticles (15-70 nm) of chemically precipitated calcium carbonate in compositions containing various plasticizers in different amounts within the claimed range. Since the frost resistance of a plastic compound also depends on the selected plasticizer and its amount, it is necessary to compare examples No. 1-7 with No. 13, No. 8 with No. 14, No. 9 with No. 15, No. 10 with No. 16, No. 11 with No. 17 . In this comparison, it follows that the frost resistance of the claimed composition is increased in comparison with the prototype by 5-10 ° C.

The introduction into the composition of the claimed composition of precipitated calcium carbonate in the claimed amount, but with a particle size of 75-105 nm or more, does not significantly reduce the melt viscosity and worsens the frost resistance of the compositions (see examples No. 18-23 in comparison with No. 1-7).

The use of precipitated calcium carbonate with a particle size of 15-70 nm in amounts outside the claimed also does not significantly reduce the melt viscosity (see examples No. 24-25).

Tensile strength and elongation at break of the claimed composition are 14.5-22.0 MPa and 300-400%, which is at the level of the prototype, where the strength and elongation are 14.0-19.7 MPa and 315-370% respectively.

Claims (1)

A composition based on polyvinyl chloride for insulation and shells of wires and cables, including a plasticizer, a heat stabilizer and a filler, characterized in that it contains chemically precipitated calcium carbonate with a surface treatment with fatty acids with a particle size of 15-70 nm, in the following ratio of the components of the composition wt.h .:
polyvinyl chloride one hundred plasticizer 40-80 thermostabilizer 3-15 chemically precipitated calcium carbonate with a particle size of 15-70 nm 0.1-8.0