CS220074B1 - Process for the production of high impact polyvinyl chloride - Google Patents

Abstract

The essence of the invention consists in treating 40 to 100 parts by weight of polyvinyl chloride at 140 to 200 °C with a crosslinking system which contains 1 to 20 parts by weight of tetraalkylthiuram disulfide, 0.5 to 10 parts by weight of metal oxides from the second and fourth groups, for example zinc, cadmium, lead, 0.1 to 10 parts by weight of higher fatty acids with a number of carbon atoms of 10 to 20. Advantageously, this crosslinking system can be used to treat 40 to 100 parts by weight of polyvinyl chloride in the presence of 5 to 60 parts by weight of a copolymer of butadiene with acrylonitrile at a temperature of 140 to 200 °C.

Description

BACKGROUND OF THE INVENTION The present invention relates to a process for the production of a high impact polymer blend based on polyvinyl chloride.

From the economic point of view, the development of new materials focuses primarily on modifications to existing mass-produced polymers. A very simple modification method is based on the production of mixtures of two or more similar or different polymers. Today, this so-called mechanical modification is mainly used to produce tough plastics based on modification of polystyrene or polyvinyl chloride by elastomers.

Another modification of polymers is their cross-linking. It is the oldest and most common method of modification, which is a key operation in the rubber industry (vulcanization J and now extends to plastic processing. Crosslinked polymers have improved mechanical properties and resistance to elevated temperatures, since glass vitrification temperature.

Of the commonly produced polymers, a butadiene-acrylonitrile copolymer is used to modify polyvinyl chloride. These polymeric modifiers are better blended with the polymer and do not migrate to the surface of the product compared to traditional low molecular weight additives [Kroman A.G., Kargin V.A .: High Mol. Soed. 8, 1703 (1966). Akutin MS, Bunijat-Zade AA, Ermakova IS, Žitkov VI, Kerber ML, Kotrelev VN, Miller VK, Redchenko BN, Shabadash AN, ETdarov EG: Plastic Massy 1971 (1), 36. Kerber ML: Plastic Massy 1971 (5) 59. Berlin AA, Kronman BI, Fedosejev BI, Sumin IG: Plastic Massy 1971/3 /, 33], improve mechanical properties and processability of mixtures (Anatasova NK, Kerber ML, Akutin MS: Plastic Massy 1977/8 /, 13 ). The methods of polyvinyl chloride modification used hitherto by the addition of an elastomer or by crosslinking could not achieve higher notch toughness values.

This drawback is overcome by the process for producing high-impact polyvinyl chloride by cross-linking at 140 to 200 ° C according to the invention, which consists in the fact that 40 to 100 wt. parts of polyvinyl chloride are treated with a crosslinking system containing 1 to 20 wt. 0.5 parts by weight of tetraalkylthiuram disulfide; 0.1 parts by weight of parts of metal oxides from the second and fourth groups, for example zinc, cadmium, lead; Preferably, the crosslinking system can be applied to 40 to 100 wt. parts of polyvinyl chloride in the presence of 5 to 60 wt. % of a butadiene-acrylonitrile copolymer having an acrylonitrile content of 10 to 50 wt. The thermoplastic polymer blend of the above process may contain 0.1 to 5 wt. parts of a polyvinyl chloride stabilizer. The thermoplastic polymer composition produced in this way is virtually completely crosslinked and contains over 90% insoluble fraction. The thermoplastic polymer blends treated as described above have notched toughness of from 3 to 80 kJ / m ² .

The present invention describes a process for the production of modified polyvinyl chloride with butadiene acrylonitrile copolymers which, in contrast to other so-called mechanically modified polymers, has higher notch toughness. This is due to the cross-linking of the polymeric material in which virtually all macromolecules are connected by cross-links to the spatial network. The crosslinking system contains common, available raw materials.

Crosslinking of polymer blends, i.e. materials already mechanically modified, results in a further increase in notch toughness of the material with better shape stability at higher temperatures. By cross-linking the polymeric material, either the same notch toughness at a lower content of the modifying component can be achieved, or a higher notch toughness at the same content of the modifying component.

The subject of the invention is illustrated in greater detail by examples.

He did

100 wt. parts of polyvinyl chloride and 1 wt. a portion of stearic acid is mixed on a heated double-cylinder at 150 ° C and the other components of the crosslinking system, i.e. 5 wt. parts of zinc oxide and 5 wt. parts of tetramethylthiuram disulfide are added at 125 ° C. This mixture has a notched toughness of 4.2 kj / m ^{2 by} pressing it at 180 ° C and 20 MPa for 30 min. a notched material of 9.4 kj / m ^{2 is obtained} .

Example 2 wt. parts by weight of polyvinyl chloride, 1 wt. part of lauric acid and 15 wt. 34 parts by weight of acrylonitrile butadiene acrylonitrile are mixed on a heated double-cylinder at 140 ° C, followed by addition of the other components of the crosslinking system at 120 ° C, i.e. 5 wt. parts of zinc oxide and 4 wt. parts of tetramethylthiuram disulfide. The resulting mixture has a notched toughness of 9 kj / m ² and after pressing at 180 ° C and 20 MPa for 10 min. It provides a notched toughness of 18 kJ / m ² and 30 kj / m ² after 30 minutes.

Example 3

100 wt. parts of polyvinyl chloride and 1 wt. part of ethylcaproic acid and 1 wt. a portion of the organotin stabilizer is mixed at a temperature of 180 ° C and 6 wt. parts of tetramethyluram disulfide and 7 wt. parts of lead oxide are added at a temperature of 130 ° C, the mechanical properties of the resulting material are the same as in Example 1. However, the material is lighter, suitable for coloring with light colors.

Example 4

8U wt. parts of polyvinyl chloride and 1 wt. stearic acid, 20 wt. parts of butadiene acrylonitrile rubber with 34% acrylonitrile and 3 wt. parts of trioxide stearate are mixed at 180 ° C. At 130 ° C, 4 wt. parts by weight of tetramethylthiuram disulfide and 5 wt. parts of cadmium oxide. This mixture, after pressing for 3 minutes at 180 ° C and at a pressure of 20 MPa, provides a notched impact material of 27 kj / m ² .

These polymer blends can be used wherever tough polyvinyl chloride is used, but at a quantitatively higher level.

Example 5 wt. parts of polyvinyl chloride and 1 wt. part of lauric acid, 20 wt. parts of butadiene acrylonitrile rubber with 26% acrylonitrile are mixed at 130 ° C and 5 wt. parts of cadmium oxide and 5 wt. parts of tetramethylthiuram disulfide. This mixture after pressing for 3 min. at a temperature of 180 ° C and a pressure of 20 MPa gives a notched impact material of 10 kj / m ² and pressed for 10 minutes under the same conditions provides a notched impact material of 20 kj / m ² .

OBJECTS

Process for producing high-impact poly-

Claims (1)

A process for the production of high-impact polyvinylchloride by cross-linking at 140-200 ° C, characterized in that it is present at 40 to 100 wt. parts of polyvinyl chloride act as a crosslinking system containing 1 to 20 wt. 0.5 parts by weight of tetraalkylthiuram disulfide; parts of metal oxides from the second and fourth groups, ILLUSTRATE, for example, zinc, cadmium, lead, 0.1 to 10 wt. parts of a higher fatty acid having a carbon number of 10 to 20, wherein the crosslinking is optionally carried out in the presence of 5 to 60 wt. parts of a butadiene-acrylonitrile copolymer having an acrylonitrile content of 10 to 50% by weight.