CS240626B1 - ABS-based blend - Google Patents

Abstract

A mixture based on ABS polymer with increased toughness, good processability while maintaining Vicat heat resistance is obtained by adding a block styrene-butadiene-styrene copolymer with a molecular weight of 50,000 to 270,000 in a concentration of 1 to 20 parts by weight, preferably 5 to 10 parts by weight per 100 parts by weight of ABS polymer.

Description

The present invention relates to a blend based on ABS polymers with improved toughness and good processability while maintaining high heat resistance of the plastic.

It is known that increasing the toughness of ABS polymers can be achieved by increasing the content of the elastomeric component or by increasing the molecular weight of the matrix (SAN copolymer).

In the first case, as the content of the rubber phase increases, the toughness of the polymer also increases. At the same time, however, the rheological properties and heat resistance of the material deteriorate. In addition, when the preparation of the ABS polymer with an increased elastomer content is carried out by emulsion polymerization, there is an increased risk of oxidation of the elastomeric component during drying of the ABS, and thus of a dryer fire.

By using ABS polymer with increased molecular weight of SAN copolymer we obtain materials with increased toughness and worse processing properties. This can be compensated by increased lubricant concentration? however, their addition radically reduces one of the key properties of ABS polymer - the heat resistance of Vicat. Furthermore, the application of these lubricants increases the risk of blooming or swelling of lubricants, thereby deteriorating the visual properties of the products.

The aforementioned drawbacks have no ABS polymer blend according to the invention. The composition according to the invention contains a thermoplastic elastomer in a concentration of 1 to 20 wt. parts, preferably 5 to 10 wt. parts per 100 wt. ABS parts.

By ABS polymer is meant a heterogeneous plastic based on acrylonitrile, butadiene and styrene / optionally in combination with alphamethylstyrene or paramylstyrene, wherein the elastomeric component may be butadiene, butadiene styrene or nitrile rubber or a mixture thereof.

By thermoplastic elastomer is meant a block styrene-butadiene-styrene copolymer linear or branched having a molecular weight of 50,000 to 270,000.

Since the thermoplastic elastomer is added to the ABS polymer only at the ready-made stage, the safety of the manufacturing process is not adversely affected. Since the thermoplastic elastomer turns _{into a} polymer melt at processing temperatures, its addition has no significant impact on the rheological properties of the composition. A further advantage of the proposed process is the use of a thermoplastic elastomer in the form of granules or discrete particles so that the working environment does not deteriorate during handling.

Other additives such as antioxidants, UV stabilizers, pigments, antistatic agents, flame retardants, lubricants, fillers, blowing agents and the like may also be present in the polymer composition of the invention.

The advantageous properties of the compositions prepared according to the invention are illustrated by the following examples.

Example 1

The thermoplastic elastomer was not added to the ABS powder polymer. The material was processed on a granulation line consisting of an extruder, a cooling tub and a mower at an extruder head temperature of 210 ° C. From the obtained granulate, test specimens were prepared on an injection molding machine with worm preplastication. Selected physical-mechanical and rheological properties were evaluated by standardized procedures:

impact strength according to ČSN 640 612, melt flow index according to ČSN 640 861 and thermal resistance Vicat on the device with air tempering according to ČSN 640 521.

Example 2

Ke 100 wt. 2 parts by weight of ABS polymer powder were added. parts of a block of styrene-butadiene-styrene copolymer weighing 69,000 (linear type). After homogenization of the mixture in a rapid mixer, the mixture was processed and evaluated for its properties in accordance with the procedure of Example 1. The results are shown in the table.

Example 3

To 100 parts by weight of ABS polymer powder was added 5 parts by weight. parts of a linear styrene-butadiene-styrene copolymer of mol. After homogenizing the mixture in a high speed mixer, the mixture was processed and evaluated for its properties according to the procedure of Example 1. The results are shown in the table.

Example 4

Ke 100 wt. 10 parts by weight of ABS polymer powder were added. parts of a linear block styrene-butadiene-styrene copolymer of mol. After homogenization of the mixture in a high speed mixer, the mixture was processed and its properties evaluated according to the procedure of Example 1. The properties of the obtained material are given in the table.

Example 5

Ke 100 wt. 18 parts by weight of ABS polymer powder were added. parts of a branched styrene-butadiene-styrene block copolymer of mol. After homogenizing the mixture in a quick mixer, the mixture was processed and evaluated for its properties in accordance with the procedure of Example 1. The material properties are given in the table.

Table

Example Impact toughness (kJ / m ² ) Melt flow index (g / 10 min) Vicat (° C) 1 103 9.2 119 2 115 9.0 119 3 142 8.4 119 4 unbreakableIny 6.7 119 5 invincible 5.9 118.5

Note that the advantages of the composition according to the invention are apparent from Examples 2 to 5.

Claims (1)

ABS-polymer blend, characterized in that it contains a styrene-butadiene-styrene block copolymer with a mole content of modifying additive. 50,000 to 270,000 in a concentration of 1 to 20 wt. parts, preferably 5 to 1Ό wt. parts per 100 wt. ABS polymer parts.