DE1134201B - Process for the production of modified plastics - Google Patents

Description

Process for the manufacture of modified plastics The invention relates to the production of graft polymers by mechanochemical reactions.

There are a number of works on the production of block mixing and Graft polymers known mechanochemically by processes in which Due to intensive mechanical action, polymers break down with the formation of freer ones Macroradicals are caused, their interaction or reaction with others Molecules, e.g. B. monomers, the formation of new chemical bonds and thus lead to the representation of new types of polymers. So far, the following combinations have been made Components made by cold kneading graft polymers1): Polymers: More natural Rubber, neoprene, styrene rubber, nitrile rubber, butyl rubber, polyester amide rubber, Polymethyl methacrylate.

Monomers: methyl methacrylate, methyl acrylate, ethyl acrylate, styrene, Acrylonitrile, divinylbenzene, ethylvinylbenzene, acrylamide.

Block polymers were also made by cold kneading two-component systems, consisting of plastomers that are produced by increasing the temperature or by adding liquids were brought into a deformable state, and monomers - without the addition of elastomers received2).

A number of block copolymers were kneaded at room temperature based on nitrile rubber with phenol-formaldehyde novolaks, epoxy resins and refined hard coal pitch3).

A special rubber kneader was used for the work mentioned with vertically arranged, spiral-shaped snails of the Whitworth shape4) and a similarly constructed special kneader, the screws of which form Archimedean spirals3), used.

It has now been found that modified plastics are obtained by that one plastomers with 0.5 to 20% of previously in organic solvents and / or cold-kneaded elastomers swollen in polymerizable monomers.

Due to the associated heavy mechanical stress on the kneaded material macro radicals are formed, their interaction or reaction with other molecules, z. B. Monomers, under the given conditions to form new chemical bonds and thus lead to the preparation of new types of graft polymers. The plastomers, z. B. polyvinyl chloride, added proportions of elastomers (0.5 to 20010, preferably 1 to 50/0), e.g. B. polybutadiene, styrene rubber, nitrile rubber, etc., are before cold kneading in an excess of swelling agents, e.g. B. polymerizable compounds, such as styrene, or organic solvents such as benzene. When cold kneading at temperatures between -50 "C and + 80 ° C, preferably at -20" C to + 20 ° C part of the monomer added, for example, in the resulting graft polymers bound.

The cold kneading can be carried out in batches, e.g. B. in internal kneaders, or continuously, z. B. in high-speed extruders.

The procedure can be carried out in such a way that that the elastomers, optionally in the presence of the plastomer, initially at increased Temperature can be kneaded with the swelling agent, followed by kneading at lower Temperature is continued.

After cold kneading is complete, volatile swelling agents can be used continued kneading, optionally at elevated temperature, removed under vacuum will.

The modified plastics obtained according to the invention are elasticized Plastomers with improved properties, especially with increased toughness.

The following examples illustrate the invention.

Example 1 In an internal kneader for high mechanical loads are 100 parts of polyvinyl chloride with 5 parts of a rubber with increased styrene content, which was swollen in 50 parts of benzene, together with the swelling agent at temperatures from -5 to - 100 C intensively under dry ice kneaded.

The coarse-grained, moist granules obtained are crushed and the swelling agent is completely removed in the heat under vacuum.

The mechanical properties were tested on standard small bars (4 6 50 mm), which had been sawn out of 4 mm thick press plates, the test the electrical properties carried out on 0.5 mm thick press plates.

A comparison was made under the same manufacturing and test conditions on polyvinyl chloride semi-finished products (hard) on test specimens made from the modified plastic notched impact strength three times higher with a slightly higher bending stress limit, more constant Tensile strength, elongation at break and Brinell hardness as well as dimensional stability which drops by around 200/0 in the heat with the Vicat needle with a thermal stability increased by about 500/0 determined according to Meixner.

The electrical properties of press plates from the modified Plastics are at or slightly above the comparative values of semi-finished polyvinyl chloride products (hard).

Example 2 Under the conditions given in Example 1 are 100 parts of polyvinyl chloride with 2 parts of nitrile rubber, which is monomeric in 50 parts Styrene was swollen, cold kneaded together with the swelling agent.

The coarse-grained granules obtained are crushed and the unreacted Monomer removed with heat under vacuum.

The properties were tested using those listed in Example 1 Conditions.

There were more than five times for the modified plastic higher notched impact strength than comparative values of polyvinyl chloride semi-finished products (hard) with the other mechanical property values falling somewhat and remaining the same electrical key figures determined.

References 1) D. J. Angier, W. F. Watson, J. Polym. Sci., 18th, 129 to 140 (1955), 20th, 235 to 250 (1956), 25th, 1 to 18 (1957).

2) D. J. Angier, R. J. Ceresa, W. F. Watson, J. Polym. Sci., 34th, 699 to 708 (1959).

3) W. Kargin et al., Chim. Prom.

No. 2, pp. 13-15 (1957).

4) W.F.Watson, D.Wilson, J. Sci. Instrum., 31., 98-99 (1954).

Claims (1)

PATENT CLAIM: Process for the production of modified plastics, characterized in that plastomers with 0.5 to 20%, preferably with 1 to 50 / o, previously in organic solvents andX or in polymerizable monomers swollen elastomers are cold-kneaded. Publications considered: German Patent No. 751 708; German regulations No. 1 056 762, 1 058 249.