CS240863B1 - ABS-based blend - Google Patents

Abstract

An ABS polymer-based mixture with improved processing properties and gloss while maintaining high Vicat heat resistance is obtained by adding an ethylene-vinyl acetate copolymer with a molecular weight of 10,000 - 500,000 at a concentration of 1 -25 parts by weight, preferably 5-10 parts by weight per 100 parts by weight of ABS.

Description

The invention relates to a mixture based on ABS polymers with improved processing properties and gloss while maintaining the high heat resistance of the plastic.

To improve the processing properties of ABS polymer mixtures, some low-molecular additives / so-called lubricants / are added, which reduce the internal friction of polymer molecules and at the same time reduce the friction between the polymer melt and the metal parts of the processing machine. These are substances based on hardened animal fat, dicarboxylic acid esters, stearic acid esters, phosphoric acid esters, etc. Since these mixtures contain a low-molecular substance in addition to the ABS polymer, during processing / due to the action of high temperature and shear forces / the interaction of both components occurs, and thus the viscosity of the melt changes and the heat resistance of the plastic decreases. In addition, these substances tend to sweat, which leads to a deterioration in the appearance of the products.

A partial solution to this problem is to reduce the molecular weight of the matrix or reduce the content of the elastomeric component. However, this results in a sharp decrease in the key mechanical properties of ABS - especially impact and notch toughness.

The mixture according to the invention does not have these drawbacks. The mixture according to the invention contains a copolymer of ethylene with a ethylene-ethylene-ethylene copolymer in a concentration of 1-25 parts by weight, preferably 5-10 parts by weight, per 100 parts by weight of ABS polymer.

By ABS polymer we mean a heterogeneous three-component system composed of butadiene, styrene and acrylonitrile, or in combination with alpha-ethylstyrene or paramethylstyrene, where the elastomer component can be butadiene, butadiene-styrene, nitrile rubber, or a mixture thereof.

- Λ240 863

Ethyl vinyl acetate copolymer is a preferred tert-butyl acetate copolymer containing 10-90% vinyl _acetate and having a molecular weight of 10,000-300,000.

The main effect of the mixture according to the invention is to achieve improved realagic properties and gloss while maintaining the high Vicat thermal stability. The copolymer can be added to the ABS powder polymer either in the form of powder or granules, so that the working process is simple and there is no deterioration of the working environment during handling. The following may also be present in the polymer mixture according to the invention: lubricants, plasticizers, flame retardants, antioxidants, antistatics, blowing agents,

UV stabilizers, pigments.

The favorable rheological, visual and thermal properties of the polymer mixture prepared according to the invention are demonstrated by the following examples:

Example 1

No modifying component was added to the powdered ABS polymer. The material was processed on a laboratory twin-screw extruder at a head temperature of 210^C. The obtained granulate was then used to evaluate the melt flow index / according to ČSN 640861 / and to prepare test specimens on an injection molding machine with screw pre-plasticization, intended for evaluating the Vicat heat resistance / on an air-tempered device according to ČSN 640521 / and surface gloss / according to the modified standard ŤGL 34087/06 - method b /. The material properties are given in the table.

Example 2

To 100 parts by weight of powdered ABS polymer, 2.5 parts by weight of n-butyl stearate and 0.5 parts by weight of Acrawax C were added. The mixture was homogenized in a Henschel high-speed mixer and processed in a laboratory twin-screw extruder at a head temperature of 210°C. Evaluation of selected properties of the mixture

3240 863 was carried out using a procedure identical to that of the example of l^SQiaÉnmali.' material are given in the table. ^A

Example 3

To 100 parts by weight of powdered ABS polymer were added 5 parts by weight of ethylene-vinyl acetate copolymer, containing 19% vinyl acetate, with a molecular weight of 15,600. The mixture was homogenized and its properties evaluated in accordance with the procedure described in Example 2. The properties of the material are given in the table.

Example 4

To 100 parts by weight of powdered ABS polymer were added 10 parts by weight of ethylene-vinyl acetate copolymer with a vinyl acetate content of 47% and a molecular weight of 102,000. The mixture was homogenized and its properties were evaluated using the same procedure as in Example 2. The properties of the material are given in the table.

Example 5

To 100 parts by weight of powdered ABS polymer was added 20 parts by weight of ethylene-vinyl acetate copolymer with a vinyl acetate content of 85% and a molecular weight of 256,000. The mixture was homogenized and its properties were evaluated using the same procedure as in Example 2. The properties of the material are given in the table.

Table

Example Melt Flow Index Vicat Heat Resistance Gloss /%/ /g/10 min./ , / ^w / 1 9.4 119 25 2 13.7 113.5 32 3 13.2 119 45 4 21.8 119 67 5 24.1 118.5 74

Note: The advantages of the mixture according to the invention are apparent from Examples 3-5.

Claims (1)

SUBJECT OF THE INVENTION. I ^{240 863} in νφ2ΜΙ6> βΉ & rj / n ^ J. It is based on an ABS polymers based on ethylene-vinyl acetate copolymer. haotnosti 10.000 - 300.000 in concentration 1-25 haot. parts / preferably 5-10 haot. parts per 100 haot. ABS polyaer parts.