HU203379B - Foil composition dispersible in caoutchouc mixtures for packing additives for rubber industry - Google Patents

Abstract

Additives packaging foils readily dispersed in rubber mixes contain 0-95 wt.% LDPE, 100-5 wt.wt.% amorphous thermoplastic elastomer and copolymers of ethylene and polar monomers and polyethylene grafted with polar monomers and 0-45% customary plastics and rubber additives.

Description

BACKGROUND OF THE INVENTION The present invention relates to a film for melting or melting of rubber caffeine for the packaging of rubber additives.

Nowadays, natural and artificial rubber bales are usually provided with low density polyethylene (KSPE) protective film. designed to eliminate certain adverse environmental effects (gelling, dusting, contamination by ultraviolet light, etc.). Other constituents of rubber mixtures (accelerators, curing agents, lubricants, carbon black, and other fillers) are increasingly being formulated and measured in PE bags. In most cases, these packagings may not be incorporated into the rubber mixture for any of the following reasons:

- the temperature of the mixes prepared in the internal mixer is not sufficient to melt and thus disperse the KSPE film, or because of the sensitivity of certain components of the mixture or the risk of the finished mixture burning:

- mixtures containing polar rubbers are incompatible with PE and the potential distribution of PE results in a significant deterioration of the physical-mechanical properties of the rubber of the mixture,

the distribution of the polyethylene film requires a 2080% extension of the mixing time beyond the high temperature of the material in the mixing chamber.

It is therefore understandable that rubber processors strictly require that no PE film be incorporated into the blend. However, this is extremely detrimental to certain products in the form of powders which are harmful to health and the environment (such as anti-aging agents, soot, fillers, etc.) and thus directly expose the worker to packaging and significant loss of time and consequent loss of production. means.

The KSPE film incorporated into the rubber blends must meet the following requirements:

- processability by extrusion technology, film blasting;

-jóhegeszthetőség;

- high throughput, - break in and out;

Melting point lower than -100 'C;

-polar character.

In order to increase the toughness of the KSPE films, i.e., the break-through, break-in and break-out strength, various rubbers are used as additives in ethylene / vinyl acetate (E / VAC) and linear KSPE. KSPE is very poorly compatible with rubbers, partially compatible with linear KSPE and E / VAC.

[P. Filzek, W.Wicke, Kunststoffe 73 (8), 427 (1983)].

It may not be used as an additive in rubber caffeine films due to its linear low density polyethylene melting point watering.

Among the rubbers, ethylene / propylene / diene terpolymers (EPDM) have been the most widespread since it has been recognized that the incorporation of partially crystalline EPDM types into KSPE can also form high tensile blends and thus films.

(G.A. Lindsay, G, J. Singleton, C.J. Carman, R.W.

Smith: Advances in Chemistry Series No. 176. Multiphase Polymers, Am. Chem. Soc., Washington, 1979, p. 367; Nos. 3,919,358 and 3,941,859. U.S. Patent Nos. 1,524,986; British patent.)

A common feature of this blend is that the polyethylene segments crystallize in the high-ethylene EPDM used, and thus the "improved compatibility with KSPE is the guarantee of high tensile elongation and tensile strength. The film blown from the blend of well-compatible and extensible blends exhibits very good physical-mechanical properties, but is perpendicular to it - the greater the elongation rate in the production direction, according to the known relationship. This means that the film is fibrillated, its permeability, intestine, and tear strength are very poor, which makes it impossible to use rubber additives as packaging materials. In order to improve the above characteristics, amorphous and sufficiently compatible rubber with KSPE should be introduced.

Of the amorphous rubbers, the introduction of butyl rubber into the KSPE is very difficult due to its incompatibility and high viscosity, and its uneven distribution endangers the productivity of the film blasting.

The use of amorphous styrene / diene block copolymers has also been unsuccessful as it gels due to the heat sensitivity of the additive (which prevents film blowing) and is also expensive and in most cases oil-diluted rubbers (softener containing premixes, etc.). they also miss you.

The low melting point PEs have either insufficient strength or processability. In some cases, for example (bitumen packing), two layer low melting point PE - strength enhancing polyamide (PA) films are used (Canadian Patent No. 1,157,824). Because of its PA content, it is not suitable for use in rubber packaging.

So far, the thermoplastic E / VAC copolymers containing 1122% by weight of VAC (U.S. Patents 4,248,348 and 4,378,067) have been found to be most advantageous as packaging films in the rubber industry. The strength or manufacturability of films made from ethylene copolymers with a higher VC content has not been found to be satisfactory (U.S. Patent No. 4,248,348). However, such E / VAC films are much more expensive than those made from KSPE, which is a limitation of their use. The KSPE is often modified with E / VAC to improve the weldability, adhesion and coating of the film. However, the properties of semi-crystalline KSPE films with E / VAC content are subject to the rules established for crystalline EPDM contents.

It is also known in the literature that when used together with crystalline EPDM and crystalline E / VAC to modify KSPE, the film has a better tensile strength than expected according to the inventors (British Patent No. 1,524,986). Here, however, it is also true that a film with good breakthrough and tear strength can be achieved only by incorporating amorphous rubber which is excluded from co-crystallization with PE and is present as a fine dispersion in the PE matrix, similar to the toughness-enhancing additive of impact-resistant polyolefin systems.

Summarizing the state of the art, there is no known film for the packaging of rubber additives which is low melting point, sufficiently oil resistant, rupture, break and tear resistant, safely manufactured and inexpensive, and can be distributed in any rubber mixture without affecting the properties of the finished product. Our aim was to formulate a film composition as described above

We have found that all of the above applies

HU 203 379 Β film is obtained by processing extrusion technology for compositions which:

0-95% by weight low density polyethylene;

100-5% by weight of thermoplastic amorphous, atactic polypropylene and EP / D / M-containing dynamic vulcanizates (Component A) and copolymers of ethylene with polar monomers or Polyethylene grafted with polar monomers (Component B), wherein the weight ratio of Components A and B is: 1: 10 to 10: 1, in addition

It contains from 0 to 45% by weight of additives and excipients known per se in the plastics and / or rubber industry.

The properties of the film produced from the described composition are as follows:

Vicat softening point: below 80 'C

Breaking strength: above 2 g / jun

It is surprising to those skilled in the art that by mixing the amorphous dynamic vulcanizate, a film which is well-extrudable, extensible, and of favorable physical-mechanical properties can be produced. Based on the nature of dynamic vulcanization, the introduction of the amorphous polymer should result in blends which, due to its "lumpiness" (the presence of gel particles), cannot be blown into a film. It is also surprising that this dynamic vulcanizate-containing film can be dispersed in the rubber blends, as the dynamic vulcanization would result in the formation of insoluble and bulk particles which are no longer dispersible.

Accordingly, the present invention provides a film composition for rubber additives which is dispersible in rubber mixtures and which:

0-95% by weight of low density polyethylene,

100-5 wt.% As Compound A as an amorphous thermoplastic elastomer and as Component B copolymers of ethylene with polar monomers, and polyethylene grafted with polar monomers, and

0-45% by weight of other additives for the plastics and / or rubber industry known per se, characterized in that component A (30-70) is: (70-30) by weight of atactic polypropylene: ethylene / propylene co- and / or ethylene / propylene / diene terpolymer composition, dynamic polyolefin vulcanizate containing not more than 50 parts by weight of filler with a Mooney viscosity between 100 and 20 ° C at 100 ° C, of component B

Polyethylene containing from 1 to 50% by weight of polar co- or graft monomer, having a melt flow index between 0,2 and 30 dg / min at 190 ° C and having a weight ratio of component A: B (1:10) (10: 1) ).

Component A of the film composition of the present invention is prepared according to Hungarian Patent Application No. 189,266.

Component B is preferably ethylene / vinyl acetate, ethylene / alkyl acrylates, ethylene / ethyl acrylate, ethylene / butyl acrylate, ethylene / hexamaleate; and ethylene / vinyl alcohol, ethylene / acrylic copolymer, and polyethylene grafted with maleic anhydride, maleic acid

The composition of the present invention is conveniently prepared by melt-homogenizing a suitable mixture of component A and component B, sometimes with low density polyethylene and other additives, directly or indirectly into a film. In the former case, the homogenized mixture was converted into granules. The film may conveniently be formed by blowing or casting onto cold rolls.

The film composition according to the invention has the following advantages:

- dispersible in any rubber mixture without endangering its properties;

its distribution does not require an increase in the temperature or time of mixing;

- because of its safe distribution, the rubber additives could be packed in it in a pre-measured manner;

- its use as a packaging means to increase mixing productivity;

- easy to produce, easy to process (weld).

The following examples illustrate the formation of the film composition according to the invention.

Example 1

44.75% by weight of low density polyethylene (melt index 190 ° C at 21.2 N at 0.7 dg / min) was mechanically blended with component B 50% melt index 0 (2 dg / min). The component is 5% by weight of dynamic vulcanizates (70 parts by weight of atactic polypropylene, 30 parts by weight of ethylene / propylene copolymer, 50 parts by weight of dolomite and chalk, 20% Mooney viscosity at 100 ° C), 0.13% by weight (Crodamide OR). (product of Croda) 0.03% by weight of butyl hydroxytoluene antioxidant and 0.09% by weight of lubricant (Lubrol 12 A9, product of ICI). The mixture was homogenized in bulk and then granulated. The granulate was blown onto a 4: 1 screw extruder by adjusting the temperature to 125/165/165/165 'C. From a mixture having a melt index of 03 dg / min, 35 µm thick film can be safely made. The material of this film has a Vicát softening point of 67 'C and a breaking strength of 3.5 g / gm.

If component B was used instead of component A, the above characteristics were 74 'C, 2.3 g / Um, respectively.

The film of the composition of Example 1 was "melted" in a mixture of polychloroprene (CR) and styrene / butadiene (SBR) with a 90 ° C emptying temperature at the usual mixing time, and a 100 ° It had to be set to C. The presence of the film in the mixture was examined by ultraviolet scanning.

Example 2

In each of Example 1, the procedure is as below, except that the quality of Component A was changed. In this case, Component A used was 5% by weight of an unloaded dynamic polyolefin vulcanizate having 30 parts by weight of atactic polypropylene and 70 parts by weight of rubber (half ethylene / propylene / diene).

EN 203 379 Β terpolymer, half of which is ethylene / propylene copolymer), and Mooney has a viscosity of 60 ° C at 60 ° C. respectively.

The mixture was blown to produce 150 µm thick heavy bags which were used to package the carbon black. Introducing soot into the internal mixer in this form reduced the mixing time by an average of 10%.

Example 3

In all the procedures described in Example 1, only the weight ratio of components A and B was changed from 1 * 10 to 10: 1. The Vicata softening point of the mixers in this case proved to be 54 'C, the film breaking strength was 3.9 g / pm

The tear and tear resistance of the 25-30 µm thick film was 92 and 50 N / mm, respectively, while those of pure A were 75 and 38 N / mm, respectively.

Example 4

In the manner described in Example 1, mixtures and films having the following composition and properties were prepared.

Component A of these exemplary compositions was 45 parts by weight of atactic polypropylene thermoplastic dynamic polyolefin vulcanizate containing 55 parts by weight of ethylene / propylene / diene terpolymer and 30 parts by weight of dolomite flour (product of Tauropren PP, Taurus).

Recipe weight% THE B C D E Low Density Polyethylene (Same as Example 1) 95 40.5 Component A: (Tauropre PP, Taurus) 2.8 9 5 50 80 Component B. ethylene / vinyl acetate (comonomer content 33% by weight, melting index: 25 dg / min) 1.0 1.0 Ethylene / vinyl acetate (same as Example 1) - 90 10 4 Ethylene / ethyl acrylate (comonomer content 19% w / w, melt index) 0.6 dg / min) 30 Ethylene / hexa-maleate (comonomer content 10% by weight, melting index 4 dg / min) - 5 4 Ethylene / butyl acrylate (comonomer content 50% by weight, melt index) 1 dg / min) 1.0 9.3 Linear low density polyethylene grafted with maleic anhydride (grafted monomer content 1% w / w, melt index 3 dg / min) 4.5

continuation

Recipe weight% THE B C D E Total component B: 2 91 9.5 49.3 8 Phenolic antioxidant 0.1 - 0.2 0.1 slip 0.1 - 0.5 0.1 Ultraviolet stabilizer - - - - 0.8 Chalk - - 45 - 11 Vicka softening point 'C 85 76 74 55 44 Tensile strength g / pm 3.2 2.9 2.6 2.3 2

All of the films on the previous formulation were completely dispersed at 95-100 ° C under normal blending times in a variety of rubber compositions and polarities. Of these, it was also suitable for packing sulfur based on formula "D" even when sulfur was added within the last 1-2 minutes of mixing.

Claims (1)

Patent Claim Point A film composition for the packaging of rubber additives, which is dispersible in rubber mixtures, which: 0-95% by weight low density polyethylene; 100-5% by weight of copolymers of amorphous thermoplastic elastomer (component A) with polar monomers of ethylene and polyethylene (component B) grafted with polar monomers, and 0-45% by weight of other additives for the plastics and / or 4c rubber industry known per se, characterized in that component A is (30-70): (70-30) by weight of atactic polypropylene: ethylene / propylene co- and / or ethylene / propylene / diene terpolymer Dynamic polyolefin vulcanisate, containing by weight not more than 50 parts by weight of a filler, with a »Mooney viscosity at 100 ° C of 2060 and containing, by weight, in the case of component B, polyethylene with a melting index of 1 to 50% by weight At C, from 0.2 to 30 dg / min, wherein A; The weight ratio of component B is (1: 10) to (10: 1). 4 Published by the National Office for Inventions, Budapest Responsible for publishing: Gabriella Swoboda Head of Department Babits - Hungarian American Publishing Company, Szekszárd