SU870414A1 - Stabilizer of thermooxidative destrucion of ethylene homo- or copolymers - Google Patents

Description

(54) STABILIZER OF THERMAL-OXIDATIVE DESTRUCTION OF HOMO OR COPOLYMERS OF ETHYLENE

one

The invention relates to the stabilization of HOMO or copolymers of ethylene and products from it by preventing thermal oxidative degradation by the addition of an antioxidant.

At elevated temperatures in the presence of oxygen, the properties of polyolefins and products from them. deteriorate due to thermo-oxidative degradation, namely: the molecular weight of the polymer decreases, the content of carboxyl groups in it increases, the physicomechanical indicators deteriorate, as a result, the service life of polymer products is reduced.

To stabilize polyolefins, it is known to use as antioxidants:.

2,2-methylene bis- (4-methyl-6) -1-methylcyclohexyl) -phenol I.

4,4-thio-bis- (6-tert-butyl-3-methylphenol (Santonoks)

tetra- (methylene-3,3,5-di-tert-butyl-4-hydroxyphenyLpropionate) methane

Irganox 1010 3

However, they all have a low resistance to polymer and thermal oxidative degradation.

The aim of the invention is to increase the resistance of ethylene homopolymer or copolymer to thermo-oxidative degradation and to expand the range of effective stabilizers.

The goal is achieved by using phosphorylated pyrazolinyl derivatives of the general formula

ten

,

R-CH I

and H "

OP (OR) 2 S-

with where R is 2,5-dimethoxyphenyl, anthracil; indolyl; ot-naphthyl; phenyl; isopropylphenyl; methoxyphenyl;

R is a methyl or ethyl group;

 phenyl; p-tolyl; 0, p-chlorophenyl,

20

as stabilizers thermo-oxidative degradation of polyolefins. The following compounds are used as heat stabilizers:

1. Dimethyl 2,5-dimethoxy25 phenyl- (1-phenyl-3-methyl-5-pyrazolinyl 4) methylphosphonic acid.

2. 2,5-Dimethoxyphenyl- {1-phenyl-3-methyl-5-pyrazol30 NIL-4) -methylphosphonic acid diethyl ester. 3. 2,5-Dimethoxy phenyl- (1-n-tolyl-3-methyl-5-pyrazolinyl-4) methylphosphonic acid dimethyl ester 4. 9-anthracyl- (ln-tolyl-3-methyl-5-pyrosolinyl diethyl ether -4J-methylphosphonate acid 5.Dimethyl ester of 3-indolyl- (l-phenyl-3-methyl-5-pyrazolinyl-4) methylphosphonic acid. 6. Diethyl ester of 3-indolyl- (1-O-chlorophenyl-3-methyl -5-pyrazolinyl-4) methylphosphonic acid, 7.Diethyl ether-C-naphthyl- (1-phenyl-3-methyl-5-pyrazolinyl-4) -methyl-phosphonic acid, 8. Dimethyl ether-C-naphthyl- (ln-tolyl- 3-methyl-5-pyrazolinyl-4) methylphosphonic acid. 9. Dioletic ester-n-methyl- (10-1 g 1-tolyl-3-methyl-5-piraeolinyl-4) -methylphosphonic acid 10 Dimethyl ester of phenyl- (1-m-tolyl-3-methyl-5-pyrazolinyl-4) methylphosphonic acid 11. Phenyl dimethyl ester (l - i-chlorophenyl-3-methyl-5-pyrazolinyl-4) methylphosphonic acid 12. P-isopropylphenyl- (1-phenyl-3-methyl-5-pyrazolinyl-4) methylphosphonic acid dimethyl ester 13. Dimethyl ether p-Isopropyl phenyl- (1-p-chlorophenyl-3-methyl-5-pyrazolinyl-4) -methylphosphonic acid 14. Dimethyl ester i-methoxyphenyl- (1-m-chlorophenyl-3-megyl-5-pyrazolinyl-4) -methylphosphonic acid. The amount of stabilizer necessary for the effective stabilization of a polymer depends on a number of factors, such as the properties of the polymer, its use, the duration and intensity of exposure to heat and oxygen of the air. Usually, it is sufficient to use 0.1-0.8%, preferably 0.10, 6%, of a stabilizer from polymer load. Stabilizers are easily introduced into the polymer by conventional methods to obtain molded products from them. For example, the stabilizer and the polymer are combined in a melt mixer. or dry. In addition, the solution or stabilizer slurry in an appropriate solvent or dispersing solvent or dispersing agent (for example, methanol, ethanol or acetone) is added to the polymer powder, followed by blending. Examples 1-16. Let us determine the displacement temperature of the onset of oxidation of high-pressure polyethylene (LDPE) from various co-compounds (1-14). Mixtures of 99.9-92.0 wt.% High-pressure polyethylene are prepared with a melt flow indicator 2.0 g / 10 m and the stabilizer indicated in Table. 1, as well as for the control of Irganox 1010 and Santonox, the content of which is 0.1-8.0 May. % The components are mixed on rollers at 130 ± 5 ° C for 1015 minutes. The friction of the zalets is 1: 1.12. Samples are tested by differential thermal analysis. The stabilizing activity of the compound is evaluated by the shift in the onset of the oxidation of the polymer to higher temperatures. The test results are summarized in table. 1. As can be seen from the above data, the greatest shift in the onset of oxidation is observed at 0.1-0.6 May. % heat stabilizer. A further increase in the heat stabilizer content, although leading to an increase in the shift in the onset of oxidation, but with a significantly lower efficiency per unit mass of the stabilizer. The introduction of heat stabilizers above 8.0 wt.% Practically does not lead to a further displacement of the onset of oxidation of high-pressure polyethylene. Examples 17-32, Determination of the temperature displacement of the onset of oxidation of low pressure polyethylene (HDPE) with various amounts of compounds (1-14). Mixtures of 99.9-92.0 wt.% Of low-pressure polyethylene ||| are prepared and with a melt flow rate of 4, O g / Ju min and. stabilizer listed in table. 2, as well as the control santonox and irganox 1010, the content of which is 0.1-8.0 May. % The polymer is displaced on rollers at ISOiS C for 10-15 minutes. The roll friction is 1: 1.12. The stabilizing activity of the compounds is estimated by the shift of the onset of the oxidation of the polymer to higher temperatures. The test results are summarized in table. 2. As follows from the above data, the greatest displacement of the oxidation channel is observed at a content of 0.1-0.6 May. % of heat stabilizers. The introduction of heat stabilizers above 8.0 wt.% Practically does not lead to further displacement of the onset of oxidation of low-pressure polyethylene. Examples 33-60. Determination of the physicomechanical characteristics of high pressure polyethylene and stabilizer compositions before and after aging. Mixtures of 99.9-99.4% by weight of high-pressure polyethylene and the stabilizer indicated in Table 2 are prepared. 3, and for the control of -antonox, the content of which is 0.1-0.6 May. %, as well as the sample without stabilizer. Samples for physico-mechanical tests were prepared by pressing (GOST 16337-77). Destructive stress at stretching is determined by GOST

12262-76. The heat resistance test (aging of the samples) was carried out in a thermometer to a screen at 160 ° C for 8 hours. The test results before and after aging are given in Table. 3

As can be seen from the above data, the physicomechanical properties of high-pressure polyethylene remain practically unchanged during the aging process, while the 4 prototype samples (Example 60) are significantly deteriorating. Thus, the elongation at break decreases from 540 to 400%, the depletion stress at break is reduced almost 1.5 times, and the yield strength decreases by 15%.

Examples 61-88. Determination of the physicomechanical characteristics of low-pressure polyethylene and stabilizer compositions before and after aging.

Mixtures of 99.9-99.4% by weight of low-pressure polyethylene and the stabilizer indicated in Table 2 are prepared. 4 and for the control of santonox, the content of which is 0.1-0.6 wt.%. A sample without a stabilizer is also prepared. Samples for physico-mechanical tests are prepared by pressing. The test is carried out according to GOST 163338-77. Thermal stability tests (aging of samples) were conducted in a heating cabinet at 160 s for 8 hours. The test results are given in Table. four.

As can be seen from the above data, the prototype of the sample (example 88} properties deteriorate significantly during the aging process. Thus, the elongation at break decreases from 400 to 320%, and the yield strength from 228 to 187 kg-s / cm as polymer samples stabilized

Stabilizer number Example number

1 2 3 4 5 6 7 8

1 2 3 4

5 6 7 8

The proposed compounds practically do not change their properties during the aging process, which indicates their high efficiency.

Examples 89-116. Determination of the physicomechanical characteristics of the compositions of a copolymer of ethylene with vinyl acetate and a stabilizer before and after aging.

Prepare mixtures from 99.9-99.4 May. % copolymer of ethylene with vinyl acetate,

0 containing 20% vinyl acetate, while the melt flow is 30 g / 10 min and the stabilizer listed in Table. 5, for control — from Santonox (0.1–0.6 May.%) And the sample without

S stabilizer. The components are mixed on rollers at 90-100 seconds for 10-15 minutes. Samples for physicomechanical tests gotov t by pressing at, time

0 exposure under pressure 5 min. Per 1 mm sample thickness. Destructive stress during stretching is determined according to GOST 12262-76. The tests for heat resistance (aging) are carried out in a heating cabinet at 160 ° C for 8 hours. The results of the tests are given in Table. five.

 -.

As can be seen from the above data, the sample stabilized by the Santonox prototype (example 116),

0 their physicomechanical deteriorates; Stva in the process of thermal aging. Relative elongation at break decreases from Soo to 600%, breaking stress at stretching reduces 5 s by 20%. Samples of ethylene-vinyl acetate copolymer, stabilized by the proposed stabilizers, practically retain their properties after thermal aging, which indicates their high efficiency.

Table 1

The shift in the onset temperature of LDPE oxidation, C, with stabilizer content, May. %

 Г 0,2 1 0,4 Т 0,6 Т 1, оТ 3,0 Г 5,0 Т 8,0

Continued table. one

Table 3

: Table 4

Table 5

Claims (3)

1. Japanese patent W 26194, cl. 25 N 611, published. 1969. 2. Japanese patent 4631, cl. 25 N 61, published. 1970. 3. Patent of Great Britain W 768684, cl. 2/6 / P, publ. 1956