SU443882A1 - Polymer composition - Google Patents

Description

one

This invention relates to the stabilization of polymer materials.

A polymeric comatosis based on a polyolefin and a stabilizing additive, 4,4-diaminodiphenyl disulfide (dithioaniline), is known. However, this composition, along with high rates, requires a significant concentration of stabilizer for a high degree of stabilization, which increases the coloring of the polymer.

In order to significantly increase the stabilization effect and reduce the durability of polyolefins, it is proposed to use a mixture of dithioaniline (4,4-diaminodiphenyl disulfide) with diphenylol prolane (4,4 dioxidiphenylpropane) in a molar ratio of 2: 1, respectively, in amounts up to 2% by weight.

The proposed mixture of compounds is a more effective thermostabilizer of polyolefins (high and low Density polyethylene and polypropylene) as compared with the Santonox used in the industry, as well as dithioaniline.

2

The effectiveness of these additives was investigated on powdered high-density polyethylene P-4020, low-density polyethylene 10702-020 and isotactic polypropylene.

The stabilizer (0.25% by weight) is introduced into high-density polyethylene and polypropylene in the form of an acetone solution, after which the solvent is removed by drying in a vacuum cabinet. A stabilizer is introduced into low density polyethylene on rollers at 150 ° C.

Films of a hydraulic pressure are made from stabilized polyethylene and polypropylene. 50 mg of polymer are cut out from the middle part of the film and placed in an oxidizing unit. The stabilizing effect of antioxidants is estimated by the iduccinic period of iri oxygen absorption and an oxygen pressure of 760 mm. Hg Art. The results of the experiments are given in table. one.

Periods of induction of the oxidation of polyolefins stabilized by individual antioxidants and synergistic mixtures at 160 ° C and P 760 mm. Hg Art.

Table 1

From tab. 1 shows that the mixture of dithioaniline + diphenylolpropane significantly exceeds the inhibitory efficacy in the same manner as dithioaniline.

In addition to determining the oxidation induction period, the inhibitory effect of these additives is determined during the thermomechanical degradation of polyethylene on rollers at 160 ° C for 6 hours. From rolled polyethylene. The effect of stabilizers on the resistance of polyethylene to thermo-oxidative degradation in the process of rolling.

within 6 hours at 160 ° C. To evaluate the effectiveness of a mixture of antioxidants against thermo-oxidative destruction of polypropylene, its low-weight and high-density thermostarena is carried out with additives of antioxidants. 0.2 mm thick films are made by pressing on a hydraulic press with heated plates. Samples in the form of double-sided spatulas are cut out of the films, mechanical tests are carried out in accordance with the requirements of GOST 270-64 on an RMI-60 tensile testing machine. The test results are shown in Table. 2

table 2

10 at 150 ° C in a heating cabinet until brittleness occurs.

The test results are shown in Table. 3. Thermostatic polypropylene in an oven at

Stabilizer

Without stabilizer

Dnioaniline (4,4-diaminodidenyldisulfide)

A mixture of dithioaniline + difennolol (4,4 dioxidiphenylpropane), 2: 1

The samples were subjected to aging - films with a thickness of 0.3 mm.

From the above data (See Tables 1-3), we conclude that the mixture of dithionyliline + diphenylolpropane (2: 1) significantly exceeds the individual dithioaniline in the inhibition performance under the same conditions. This mixture at a molar ratio of dithioaniline: diphenylolprol is 2: 1 with an addition of 0.2-0.3% by weight. does not stain the polymer. When large amounts are added, a light yellow tint appears. The mixture of antioxidants is not washed out with water and aggressive media, it is good to mix, it lasts Time before the onset ..

Lenp fragility,

hour

3

0.25

60 78 0.25

with polymer

Does not bleed out of it during storage.

Subject invention

Polymer composition based on polyolefin and stabilized, with 4,4-diaminodiphenyl disulfide additive, characterized in that, in order to improve the stability of the properties of the composition, 4,4-diaminodiphenyl disulfide is introduced into it together with diphenylol propane in a 1: 2 molar ratio - 2: 1, respectively, in an amount of 0.2-2% by weight of Polyolefin. Table 3 150 ° C before the onset of fragility