CS241865B1 - A mixture of linear and branched polyethylene - Google Patents

Abstract

The invention relates to a mixture of linear and branched polyethylene suitable in particular for the production of floor coverings in sports areas. The mixtures contain 15 to 49% by weight of linear polyethylene with a flow index of 5 to 7 g/10 min. at 190 °C, 50 to 85% by weight of branched polyethylene with a flow index of 6 to 8 g/10 min. at Ϊ90 °C, 0.Q5 to 0.2% of a phenolic antioxidant of the general formula HO c(ch5)5 — \\. - (CH2)2C00R c(ch5)5 where R is hexadecyl to octadecyl or symmetrically substituted pentaerythrityl, 0.05 to 0.5% by weight of triphenylphosphite and 0.05 to 0.5% by weight of tetramethylpiperidine derivatives, pigments and optionally other processing additives. Stabilizers must be mixed into the mixture in the form of a concentrate in linear polyethylene, then the floors have a good service life.

Description

Mixture of linear and branched polyethylene

The invention relates to a mixture of linear and branched polyethylene suitable in particular for the production of floor coverings in sports facilities. The blends contain 15 to 49% by weight of linear polyethylene having a flow index of 5 to 7 g / 10 min. at 190 ° C, up to 85% by weight of branched polyethylene with a flow index of 6 to 8 g / 10 min. at Ϊ90 ° C, 0, Q5 to 0.2% of the phenolic antioxidant of formula

HO c (ch ₅ ) ₅ -

\\.

- (CH ₂₎ C00R ₂ C (CH _{5) 5} wherein R is hexadecyl and octadecyl or a symmetrically substituted pentaerythrityl, 0.05 to 0.5% by weight of triphenyl phosphite and 0.05 to 0.5% by weight of derivatives of tetramethylpiperidine, pigments and optionally other processing ingredients. The stabilizers must be mixed into the mixture in the form of a concentrate in linear polyethylene, after which the floors have a good durability.

241,865 (51) Int Cl *

OJ C 08 L 25/06

241 865

The invention relates to stabilized mixtures of linear and branched polyethylene. These mixtures are used in particular for the production of floor coverings.

Recently, higher demands have been placed on sports floor coverings, produced as a perfect replacement for the natural surfaces of tennis courts, playgrounds and social areas of residential houses and recreational facilities. Coverings shall be made of materials which, in terms of mechanical properties, are closest to the ideal requirements for ball reflection, mobility of the player on the playing field, taking into account the dilatation ratios of the playing surface when changing outside temperature. Last but not least, these are the durability issues of these floor coverings. The assembled surfaces are relatively expensive and their potential failure also carries a high risk of injury. Therefore, the degraded parts of the playing area must be replaced in whole or in part in time to reduce the risk of parts cracking at the time of application.

Currently, tennis court floor coverings are produced from a mixture of branched polyethylene with a flow index of 6 to 8 and linear polyethylene with a flow index of 5 to 6 g / 10 min. Both polymers are stabilized with a conventional phenolic antioxidant of very low concentration.

The mixture, consisting of about 80% by weight of branched and 20% by weight of linear polyethylene, is first homogenized and individual parts of the floor covering are manufactured in the injection molding machine, which are mounted in place on the playing field. If these playing areas are mounted inside enclosed areas, the area is not exposed to sunlight and normal climatic conditions, the service life of these areas is considerably high. However, if such a playing surface is exposed to direct sunlight, a rapid photooxidation occurs under these conditions

241 865 degradation of the covering surface. In addition, photooxidation is catalysed by impurities that diffuse from the surface to the polyethylene parts in the rain, which further complicates the degradation processes in the polymeric material with metal catalyzed photooxidation degradation.

However, the deterioration of good performance of polyolefins over time is a characteristic of these polymers.

For example, linear, branched polyethylene products and mixtures thereof are known to be exposed to elevated temperatures, oxygen and sunlight and undergo rapid oxidation, accompanied by deterioration of mechanical properties to the extent that the products become brittle, crack and lose their original good mechanical properties .

In order to prevent these undesirable effects, a number of methods are used to protect them. The shielding principle is based on the homogenization of said polymeric materials with substances capable of absorbing the entire ultraviolet, visible and near infrared region of the spectrum. For example, carbon blacks and oxides of some transition metal valency metals are commonly used for this purpose. Polymers containing these substances in a higher concentration behave as permanently stored in the dark, which has a favorable effect on their photooxidation stability.

Various phenolic antioxidants, amines, phosphites, thiodipropionic acid esters are used to protect polyolefins against the effects of elevated temperatures and oxygen. The purpose of these substances is to protect polymers against undesired thermo-oxidative degradation in the preparation of the granulate and its processing into the final product and in the application of the final products at elevated temperatures. Protection of polyolefins against the effects of solar radiation is provided by two basic groups of substances. They are ultraviolet absorbers, such as benzophenone derivatives, benzotriazole and salicylic acid esters, which absorb the shortwave region of ultraviolet radiation and convert it into radiation at larger wavelengths whose energy is lower than that of the weakest bonds occurring in the polymer system. Among the most effective substances recently used to inhibit photooxidative degradation of polyolefins are

241,865 a group of HALS, i.e., piperidine and piperezine derivatives.

However, it has been shown that stabilizing mixtures effective either in linear polyethylene or in branched polyethylene do not guarantee sufficient stabilization of the mixtures of both types of polyethylene used for floor coverings. This is due to the different requirements of the two types of polyethylene on the properties of the stabilizers, the specific requirements for use on floor coverings and, in particular, the method of preparing the mixture and mixing the stabilizing ingredients.

The present invention relates to mixtures of linear and branched polyethylene with additives of pigments, phenolic, phosphite and piperidine stabilizers and optionally other processing additives which contain 15 to 49% by weight of linear polyethylene having a flow index of 5 to 7 g / 10 min. at 190 ° C, 50 to 85% by weight of branched polyethylene with a flow index of 6 to 8 g / min. at 190 ° C, 0.03 to 0.2% by weight of the phenolic antioxidant of the formula I.

(ch ₂ ) ₂ COOR wherein R is hexadecyl to octadecyl or symmetrically substituted pentaeritrityl, 0.05 to 0.3% by weight of triphenylphosphites, the phenolic groups of which may be substituted with 6 to 12 carbon atoms or styryl and 0.05 to 0, 3% by weight of tetramethylpiperidine derivatives, wherein the stabilizers are mixed into the mixture in the form of a concentrate in linear polyethylene.

In a linear polyethylene-branched polyethylene mixture, the low molecular weight component of linear polyethylene greatly affects the final stability of the final product. This low molecular weight moiety is the most sensitive component in terms of product stability. In this part of the polymer system, degradation products formed in the primary stage of thermo-oxidative degradation accumulate, i.e. at the time of preparation of the granulate and its processing into the final product. These low molecular weight polymers cannot be polymerized

241 865 of the system, and therefore, methods must be used which allow a perfect stabilization of these low molecular weight parts and thus of the entire polymer system.

A detailed examination of the solubility of the various stabilizing components in the low molecular weight fraction of linear polyethylene has shown that optimum results are obtained using a ternary stabilization system composed of a phosphite, phenolic and piperidine component, which is added to the mixture as a concentrate in linear polyethylene.

It is a ternary system composed of: a piperidine component characterized by a structural formula

wherein X is oxygen or nitrogen and R is a group having a molecular weight of at least 120, _R2 is hydrogen .or phenolic compounds characterized by the structural formulas

wherein X is tert-butyl and R is hexadecyl or octadecyl or symmetrically substituted pentaeritrityl and phosphite components characterized by a structural formula of the type

wherein Y is octyl to decyl or styryl

The production of mixtures of linear and branched roofing can be organized according to the appropriate method.

polyethylene for use in accordance with the present invention

241 865

Manufacturers of linear and branched polyethylene will only prepare granulates with basic stabilization against teraoxidative destruction. These granulates are mixed in a prescribed batch and additive to the stabilizing concentrate * in linear polyethylene which adjusts the level of the stabilizing ingredients in the polymer mixture to the desired level. A floor covering is made from a mixture of granulates and concentrate on an injection molding machine. This production arrangement offers great advantages over the * other * production * organization in that way. The floor coverings can thus be produced from granulates which produce petrochemical products in mass production for conventional applications. By concentrating the stabilizing components in the stabilizing concentrates, the properties of the resulting materials from which the coverings are made can be smoothly controlled. As a stabilizer concentrate using linear polyethylene as a carrier is used for the additive, it is possible to control not only the concentration of stabilizing components in the linear-branched polyethylene mixture, but also the concentration ratio of the two types of polymers by concentrating the additive mixture. , which in various cases contains lower or higher concentrations of the polymeric carrier. This prepared stabilizing concentrate is perfectly homogenized with linear * polyethylene * forming a constituent of the base polymer blend and, in the next stage of the injection process, with branched polyethylene *. This progressive * mixing * achieved the best melt homogeneity, which was confirmed both by stability tests and microscopically.

The following examples illustrate the invention. % in the examples given are by weight.

Used polymers

I. Branched natural polyethylene Bralen Z 2001 RA-7-20.

II. Branched polyethylene red pigmented Bralen Z 2001-101

III. Branched polyethylene white pigmented Bralen Z 1201

IV. Branched polyethylene yellow pigmented Bralen Z 1901

V. Branched polyethylene green pigaented Bralen Z 2001-502

VI. Linen polyethylene Liten MB 62 in natural color.

Used stabilizing additives

/ 6 - (3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid octadecyl ester (eg Irganox 1076)

B-tetrakis (methylene-3- (3,5 * 5-di-tert-butyl-4-hydroxyphenyl) propionate methane (for example Irganox 1010 or Fenozan 23)

C - polymeric HALS type

CK ₃ oo ^ch 3 0¾

- · ° - Η / H - (OH ₂ ) ₂ - O - C - (CH ₂ ) ₂ - C - O (CH ₂ ) ₂ - / KO ^ 3

CH ₃ CH ₃ h CH ₃ CH ₃ eg Tinuvin 622

- o - c - (ch ₂ ) ₂ - C - where n is more than 5 D - bis 2,2,6,6 tetramethyl-4 piperidinyl sebacate (eg Tinuvin E - polymeric HALS type 77Q)

CH

CH.

CHCH ₃ _2 ^^ ^N \ ZL_ CH:

N

<CH ₂ ) ₆

Uh.

^C ? 3 ₉ - v - vH _? for example, Chimasorb 944 ci.

3 3 3

F - tetramethyl piperidinyl stearate (eg Dastib 845) G - piperidine derivative with structural configuration

for example Diacetam 5

241 865

Tr - tris - nonylphenyl phosphite (eg Irgafos TNPP or Weston 399)

CH - tris - styrylphenyl phosphite (eg Antioxidant 6)

Example 1

From a mixture of granulates containing 79.5% type II polymer. 20% of Type VI., 0.1% of antioxidant A, 0.2% of antioxidant C and 0.2% of antioxidant H as a concentrate in linear polyethylene were manufactured floor covering parts on an injection molding machine. A portion of the covering was pressed onto a 0.5 mm sheet and irradiated in the Xenotest 450 until the ductility dropped to half its original value. The time required to reach this value was 4,100 hours. Example 2

From a mixture of granulates containing 79% type I polymer, 20% type VI., 0.1% antioxidant B, 0.2% antioxidant E, 0.2% antioxidant H, 0.48% chromium oxide and 0.02% carbon black As a concentrate in linear polyethylene, floor covering parts were produced on an injection molding machine. A portion of the covering was crimped onto a 0.5-sheet film and irradiated in the Xenotest 450 until the ductility dropped to half its original value.

The time needed to reach this value was 3.950 hours.

Example 3

From a mixture of granulates containing 79.5% type III polymer, 20% type VI, 0.1% antioxidant A, 0.2% antioxidant F, and 0.2% antioxidant CH as a concentrate in linear polyethylene, they were made on an injection molding machine floor coverings. A portion of the covering was pressed onto a foil of 0.5 aa thickness and exposed in the Xenotest 450 until the ductility decreased to half its original value. The time required to reach this value was 3,690 hours.

Example 4

Floor and flooring granules containing 49.5% of polyaera IV, 50% of polymer VI, 0.1% of antioxidant A, 0.2% of antioxidant G, 0.2% of antioxidant H as a concentrate in linear polyethylene coverings. A portion of the covering would be pressed onto a 0.5 mm sheet and exposed in the Xenotest 450 until the ductility dropped to half its original value. The time required to reach this value was 3,530 hours.

From a mixture of granulates reaching 79.5% polymer II., 20% polymer VI., 0.1% antioxidant A, 0.1% antioxidant C, 0.1% antioxidant D, 0.1% antioxidant H, and 0.1% The antioxidant CH, as a concentrate in linear polyethylene, was made of floor covering parts on an injection molding machine, part of the covering was pressed onto a 0.5 mm thick film and exposed in the Xenotest 450 until the ductility dropped to half its original value.

The time required to reach this value was 3.980 hours.

Example 6

From a mixture of granulates containing 79.55% polymer II. 20% of polymer VI, 0.05% of antioxidant A, 0.3% of antioxidant C and 0.1% of antioxidant H as a concentrate in linear polyethylene, floor covering parts were made on an injection molding machine. A portion of the covering was pressed onto a 0.5 mm sheet and exposed in the Xenotest 450 until the ductility dropped to half its original value. The time required to reach this value was 4,230 hours.

Example 7

From a mixture of granulates containing 84.35% polymer II., 15% polymer VI., 0.05% antioxidant B, 0.1% di-tert-butyl p-cresol, 0.1% antioxidant E, 0.1% antioxidant G, 0.3% of the antioxidant CH, as a concentrate in linear polyethylene, were made on the injection molding machine with floor covering parts, a portion of the covering was pressed onto a 0.5 mm thick film and exposed in the Xenotest 450 until the ductility decreased to half its original value. The time required to reach this value was 4,060 hours.

Example 8

From a mixture of granulates containing 49.6% polymer II., 50% polymer VI., 0.05% antioxidant A, 0.05% antioxidant B, 0.1% antioxidant C, 0.1% antioxidant D, 0.1% antioxidant £,

0.2% of the antioxidant H, as a concentrate in linear polyethylene, were made on the injection molding machine floor covering parts.

A portion of the covering was pressed onto a foil of 0.5 mm thickness and irradiated in the Xenotest 450 until the ductility dropped to po10.

241 865 of the original value. The time required to reach this value was 3,930 hours.

Example 9

From the granulate blend containing 79.5% polymer V, 20% polymer VI, 0.1% antioxidant A, 0.2% antioxidant C, 0.2% antioxidant H as a concentrate in linear polyethylene, floor parts were made on an injection molding machine coverings. A portion of the covering was pressed onto a 0.5 mm sheet and irradiated in the Xenotest 450 until the ductility dropped to half its original value. The time required to reach this value was 4,080 hours.

Example 10

From a mixture of granulates containing 79.9% polymer II. 19.95% of polymer VI., 0.1% di-tert. butyl p. cresol, 0.05% of antioxidant B were manufactured on the injection molding machine with floor covering parts. A portion of the covering was crimped onto a 0.5 mm sheet and exposed in the Xenotest 450 until the ductility dropped to half its original value. The time required to reach this value was 480 hours.

Example 11

From a mixture of granulates containing 79.55% polymer V., 20% polymer VI., 0.1% di-tert. butyl p. cresol, 0.05% antioxidant B, 0.3% 2 hydroxy-4-octyloxybenzophenone were manufactured on the injection molding machine with floor covering parts. A portion of the covering was crimped onto a 0.5 mm sheet and irradiated in the Xenotest until the ductility dropped to half its original value. The time required to achieve this was 930 hours.

Example 12

From a mixture of granulates containing 79.5% type II polymer, 20% type VI., 0.1% antioxidant A, 0.2% antioxidant C and 0.2% antioxidant H (the stabilizing ingredients were blended into branched polyethylene ) the floor covering parts were made on the injection molding machine. A portion of the covering was pressed onto a sheet of 0.5 ® thickness and irradiated in the Xenotest 450 until the ductility dropped to half its original value. The time required to reach this value was 2.050 hours. The result indicates poor homogeneity of the resulting material.

Claims (1)

SUBJECT OF THE INVENTION 241 865 Mixture of linear and branched polyethylene with additives of pigments, phenolic, phosphite and piperidine stabilizers and optionally other processing additives, characterized in that it contains 15 to 49% by weight of linear polyethylene with a flow index of 5 to 7 g / 10 min. at 190 ° C, 50 to 85% by weight of branched polyethylene with a flow index of 6 to 8 g / 10 min. at 190 ° C, 0.03-0.2% by weight of the phenolic antioxidant of formula. HIM C (CH ₃ ) ₃ wherein R is hexadecyl to octadecyl or symmetrically substituted pentaeritrityl, 0.05 to 0.3% by weight of triphenylphosphites whose phenolic groups may be substituted with 6 to 12 carbon atoms or styryl and 0.05 to 0 3% by weight of tetramethylpiperidine derivatives, wherein the stabilizers are mixed into the mixture as a concentrate in linear polyethylene.