CS259929B1 - Copolymers of ethylene with propylene or butylene - Google Patents

Abstract

The present invention relates to ethylene copolymers with propylene or butene produced on carrier catalysts containing 0.001 to 5 mol% butene or propylene component, flow index 0.01 to 0.60 g / 10 min, stabilized 0.05 to 0.02% by weight of 2,6-di-tert-butyl-4-methylphenol, 0.05 to 0.12% by weight of tetrakis (methylene-3- (3 *, 5'-di-tert-butyl-4'-hydroxyphenylpropionate) or octadecyl ester beta- (3 ', 5' - di-tert-butyl-4'-hydroxyphenyl) propionic acid and 0.1 to 0.3% weight of trisnonylphenyl phosphite. Copolymers have very good processing properties, especially when blowing.

Description

The invention relates to ethylene copolymers intended for the production of films and possibly other blown products.

Ethylene copolymers, like other types of polyolefins, tend to undergo thermooxidative and photooxidative degradation during processing to final products and when applied at elevated temperatures in the presence of oxygen and sunlight. The higher the molecular weight of a polymer, the greater its stability requirements and the more difficult its processing. Therefore, high molecular weight types of linear ethylene copolymers intended for the production of thin films and the blowing of large-volume hollow articles need to be particularly well stabilized.

Up to now, granulates intended for these demanding technologies have been produced by stabilizing the ethylene powdered linear copolymers with a binary mixture of a phenolic non-volatile antioxidant, a sulfur compound or a phosphite in a concentration ratio of about 1: 1. The granulate prepared by extrusion of the powder mixture is then processed to a microtene film. Granules which do not conform to the foil quality are processed, for example, into large-volume containers, by mixing them with stabilizing concentrates containing components protecting the final product against the effects of sunlight before entering the extruder.

Phenolic antioxidants used to prepare these binary mixtures with phosphites such as 1,3,5-trimethyl-2,4,6-tris (3 ', 5'-di-tert-butyl-4'-hydroxybenzyl) benzene, 1,3-tris (2'-methyl-4'-hydroxy-5-tert-butylphenyl) butane, tetrakis [methylene-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl propionate) methane, bis [3, 3-bis- (3'-tert-buty-1-4'-hydroxyphenyl) butyl] succinate, bis (2,2'-methylene-bis (4-methyl-6-tert-butylphenyl) terephthalate .

These high molecular weight phenolic antioxidants, which are very difficult to synthesize, are very expensive and thus increase the stabilization costs of the granulation.

Since only high-molecular-weight types of ethylene copolymers, which often tend to cross-link, can be used for the production of films and hollow articles, the production and processing of these granules is always associated with a considerable degree of risk. With a small increase in the concentration of polymerization catalysts, the stabilizing system is not sufficient to block their catalytic effect during thermo-oxidation. This allows cross-linking reactions, which are manifested in the macroscale by a rapid decrease in the granulate flow index. The greatest difficulty arises during the production of the film itself, when the sieving often occurs to such an extent that the polymer melt is permeated by unprocessable macrogels, which cause perforations in the film blowing, air leakage from the blown sleeve, or even tearing. Therefore, more expensive special foil types of ethylene copolymers are used.

The present invention provides copolymers of ethylene with propylene or butene produced on supported catalysts containing 0.001 to 5 mole% butene or propylene component and having a flow index of 0.01 to 0.60 g / 10 min containing 0.05 to 0.2 % by weight of 2,6-di-tert-butyl-4-methylphenol, 0.05 to 0.12% by weight of tetrakis [pietylene-3- (3 ', 5'-di-tert, butyl-4'-hydroxyphenylpropionate)] methane or beta-octadecyl ester beta - (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionic acid and 0.1 to 0.3% by weight of tris-nonylphenyl phosphite.

Linear ethylene homopolymers are unsuitable materials for blowing films and large-volume containers. Especially in the production of films, the copolymerizing component guarantees better elongation and hence high draw-off speeds. These positive properties are particularly highly appreciated in the production of stretchable bands and microtene films.

In addition to the appropriate choice of copolymer component, an important value is the molecular weight of the copolymer, expressed as a melt flow index. The lower the flow index, the better the mechanical properties of the final products. This limiting value is usually around 0.01 g / 10 min. Below this value, said copolymers of ethylene with butene or propylene are unprocessable by blow molding. As the flow index increases, the performance of processing lines increases, but usually at the expense of good mechanical properties of the products. The maximum limiting flow index of the copolymers is 0.60 g / 10 min.

Systematic investigation of stabilization systems revealed that some binary mixtures composed of high molecular weight, structurally complex phenolic antioxidant and phosphite can be replaced by a three-member stabilization system composed of two phenolic antioxidants and phosphite. synergism of adducts of the -OH ..... PJ type, ie substances that form intermolecular hydrogen bridges between the phenolic and phosphite components of the stabilization system. These adducts are capable of producing synergetic effects at elevated processing temperatures which are so significant in intensity that they can compete in efficiency with binary stabilization systems made up of high molecular weight phenol and phosphite.

Such combinations are, for example, an adduct of 2,6-di-tert-butyl-4-methylphenol with trisonylphenyl phosphite, which constitutes one component of the stabilizing system, while the other component consists of an adduct of high molecular weight substituted phenol and trisnonylphenyl phosphite.

Surprisingly, a good stabilizing effect is achieved at substantially lower costs by maintaining the following technological process.

A powder stabilizer concentrate is first prepared from a powdered linear copolymer of ethylene with butylene or propylene and 2 types of phenolic antioxidants, which is dosed in a prescribed ratio into a powdered linear copolymer of ethylene with butylene or propylene.

In the last stage, liquid trisnonylphenyl phosphite is sprayed into the mixture before the kneader, the resulting mixture is extruded and granulated, and the granulate produced contains 2 types of adducts, free phenols, phosphite and oxidation products of all 3 primary components. Experiments carried out with different concentration ratios of these 3 components have shown that optimum results are obtained when the concentrations of primary products 2,6-di-tert-butyl-4-methylphenol: high molecular weight phenol: phosphite are in the range of concentration ratios (1 to 4). ) :( 1 to 2.5) :( 2 to 6) by weight. The granulate produced in the next stage is processed, for example, by blowing it to a microtene film thickness of 0.005 mm, to a film thickness of 0.030-0.050 mm, which are then cut into tapes which are woven on jet looms in the next stage of processing. In addition to foil processing, large-scale production of large-volume containers by blowing is very popular in that the granulate produced is mixed with various processing ingredients and, for example, on the Voith-Fischer line is processed into cans, barrels, cans and other hollow articles.

Experiments carried out at different concentration ratios of the ternary system indicated that optimum technological and economic results are obtained when the concentrations of the primary products 2,6-di-tert-butyl-4-methylphenol: high molecular weight phenol: phosphite are within the concentration range. ratios (1 to 4) :( 1 to (2.5) :( 2 to 6).

The following examples illustrate the invention. The percentages given in the examples are by weight unless otherwise indicated.

Additives used

1. 2,6-di-tert-butyl-4-methylphenol (ANTIOXIDANT 4K),

2. tetrakis Qnetylene-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenylpropionate)] - methane (IRGANOX 1 010);

3. beta- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionic acid octadeoyl ester (IRGANOX 1 076);

4. Trisnonylphenyl phosphite (IRGAFOS TNPP).

Used ethylene copolymers

Copolymer A

Ethylene-butene linear copolymer powder, containing 4.4 mole% butene component, prepared on supported catalysts with a flow index of 0.62 g / 10 min.

Copolymer Β

Ethylene-butene linear copolymer powder, containing 0.2 mol% butene component, prepared on supported catalysts with a flow index of 0.20 g / min.

Copolymer C

Ethylene-butene linear copolymer powder, containing 0.001 mole% butene component, prepared on supported catalysts, flow index 0.01 g / 10 min.

Copolymer D

Ethylene-propylene powdered linear copolymer containing 4.3 mol% propylene component, prepared on supported catalysts, flow index 0.58 g / 10 min.

Copolymer E

Ethylene-propylene powdered linear copolymer, containing 0.11 mol% propylene component, prepared on supported catalysts, flow index 0.41 g / 10 min.

Copolymer F

Ethylene-propylene linear copolymer powder, containing 0.001 mol% propylene component, prepared on supported catalysts, flow index 0.02 g / 10 min.

Copolymer G

Ethylene-butene powdered linear copolymer containing 0.2 mole% butene component, prepared with Ziegler-Natta catalysts, having a flow index of 0.31 g / 10 min.

Copolymer H

Ethylene-propylene linear copolymer powder, containing 0.1 mol% propylene component, prepared with Ziegler-Natta catalysts, having a flow index of 0.48 g / 10 min.

Example 1

A powder concentrate was prepared from powder copolymer A and additives 1 and 2, which was subsequently fed into the main stream of powder copolymer A in the next stage of the process, and the last additive was continuously fed into the main stream of powder copolymer A by stabilizer 4. The mixture of powder copolymer A before granulation was 0.1% of additive 1, 0.05% of additive 2 and 0.2% of additive 4. After extrusion and granulation, the granulate was processed in a Davo Visosystem on a 0.015 mm thick film. During the one-hour test, there were no macrogels, no film perforation, transverse film strength of 38.8 MPa, longitudinal strength of 47.2 MPa, impact strength of 51.2 g.

Example 2

A powder concentrate was prepared from powder copolymer B and additives 1 and 2, which was fed into the main stream of powder copolymer B 'in the next stage of the process, and the last additive was continuously fed into the main stream of powder polymer and dosing pump. The final blend of powdered copolymer A prior to granulation was 0.1% of additive 1, 0.05% of additive 2 and 0.2% of additive 4. After extrusion and granulation, the granulate was processed in a Davo Visosystem on a 0.015 mm thick film. Macrogels did not appear during the one-hour test, there was no perforation of the film, the transverse strength of the film was 39.1 MPa, the longitudinal strength of 46.1 MPa, the impact strength of 50.08 g.

Example 3

A powder concentrate was prepared from powder copolymer C and additives 1 and 3, which was subsequently fed into the main stream of powder copolymer C in the next stage of the process, and the stabilizer 4 was continuously fed into the main stream of powder copolymer C. of the powder copolymer C mixture prior to granulation was 0.15% of additive 1, 0.05% of additive 3 and 0.3% of additive 4. After extrusion and granulation, the granulate was blow molded into 501 liter drums on a Voith-Fischer line. The production did not cause any humiliation, a homogeneous thickness was found in a 501 liter barrel, the barrel showed the required weight, and a drop test showed good mechanical properties of the product.

He attaches

A powder concentrate was prepared from powder copolymer D and additives 1 and 2, which was fed into the main stream of powder copolymer D in the next stage of the process and additive 4 was continuously metered into the main stream of powder copolymer D as the last additive. The mixture of powder copolymer D before granulation was 0.2% of additive 1, 0.12% of additive 2 and 0.3% of additive 4. After extrusion and granulation, the granulate was blow molded to a stretch film of 0.40 mm in a Lenzing machine. No film breakage occurred during the five-hour test.

Example 5

A powder concentrate was prepared from powder copolymer E and additives 1 and 2, which was fed into the main stream of powder copolymer E in the next stage of the process and additive 4 was continuously fed into the main stream of powder copolymer Ε as the last additive. of the powder copolymer E prior to granulation was 0.1% of additive 1, 0.07% of additive 2 and 0.2% of additive 4. After extrusion and granulation, the granulate was blow molded to a 0.041 mm thick stretch film in a Lenzing machine. No film breakage occurred during the five-hour test.

Example 6

A powder concentrate was prepared from powder copolymer F and additives 1 and 2, which was fed into the main stream of powder copolymer F in the next stage of the process and the last additive was continuously fed into the main stream of powder copolymer F by a dosing pump. of the powder copolymer F prior to granulation was 0.15% of additive 1, 0.05% of additive 2 and 0.2% of additive 4. After extrusion and granulation, the granulate was blow molded into 501 liter drums on a Voith-Fischer line. The production did not cause any problems, a homogeneous thickness was secured in a 501 liter barrel, the barrel showed the required weight, and a drop test showed good mechanical properties of the product.

Example 7

A powder concentrate was prepared from powder copolymer A and additive 1, which was fed into the main stream of powder copolymer A in the next stage of the process, and the stabilizer 4 was continuously fed into the main stream of powder copolymer A by dosing pump. the granulation was 0.2% of additive 1 and 0.2% of additive 4. After extrusion and granulation, the granulate was processed in a Davo Visosystem. During the one-hour test it was possible to produce a minimum film thickness of 0.050 mm, there were 4 film breaks and 15 perforations. The film exhibited haze and considerable brittleness.

Example8

A powder concentrate was prepared from powder copolymers G and additives 1 and 2, which was fed into the main stream of powder copolymers G at the next stage of the process, and the last additive was continuously fed into the main stream of powder copolymers G by a dosing pump. before granulation, 0.1% of additive 1, 0.1% of additive 2 and 0.1% of additive 4. After extrusion and granulation, the granules were processed in a Davo Visosystem. During the one-hour test it was possible to produce a minimum film thickness of 0.045 mm, there were 3 breaks and 12 perforations of the film, which showed very low mechanical properties.

Example 9

A powder concentrate was prepared from powder copolymers H and additives 1 and 2, which was fed into the main stream of powder copolymers H in the next stage of the process and additive 4 was continuously fed into the main stream of copolymers H as a last additive. prior to granulation of the copolymers H, 0.1% of additive 1, 0.1% of additive 2, and 0.1% of additive 4 were obtained. After extrusion and granulation, the granulate was blow-blown into a stretch film of 0.039 mm thickness. During the test, the film cracked during stretching.

Claims (1)

SUBJECT OF THE INVENTION Copolymers of ethylene with propylene or butylene, prepared on supported catalysts, containing from 0.001 to 5 mol% of a butylene or propylene component and having a flow index of 0.01 to 0.60 g / 10 min, characterized in that they contain 0.05 to 0, 2% by weight of 2,6-di-tert-butyl-4-methylphenol, 0.05 to 0.12% by weight of tetrakis [methylene-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl-propionate) methane, or beta- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionic acid octadecyl ester and 0.1 to 0.3% by weight of trisnonylphenyl phosphite.