CS236331B1 - Mixture based on polyvinylaromatic matter - Google Patents

Abstract

The mixture based on polyvinyl aromatic material solves the problem of improving the strength, theological and appearance properties. The polymer mixture based on polyvinyl aromatic material contains as an internal lubricant a combination of isobutyl esters of C14, C16 and C18 fatty acids with saturated animal fats.

Description

The invention relates to a polymer mixture based on polyvinyl aromatic material, which exhibits improved mechanical, theological and aesthetic properties.

It is known that polyvinyl aromatic materials, if improved mechanical properties are required, must be prepared so that their molecular weight, or the components present that modify toughness, are significantly higher than in commonly used types, where the weight average molecular weight most often ranges from 200 to 400 thousand and the elastomer content fluctuates from 10 to 20% by weight. However, a higher molecular weight and an increase in the elastomer content have a negative impact on the processability, rheological properties and appearance of products prepared from these materials.

Good rheological, processing and appearance properties can be achieved by reducing the molecular weight or reducing the content of elastomers in the polymer. However, this results in a decrease in the strength characteristics of the produced material, especially impact strength. The same effect, i.e. in

Improvement of processing and rheological properties can be achieved by adding so-called lubricants.

There are a number of lubricants that regulate rheological properties, but do not meet other requirements of processors and demands arising from the application sphere. Thus, amines, amides, some metal salts and fatty acid esters cannot be used for a number of applications, because on the one hand they do not meet the requirements of health safety and on the other hand their presence in the polymer substrate results in a decrease in key strength characteristics. . Lubricants that contain unsaturated bonds

z. 236 331 in the chain, increase the susceptibility of the modified polymer to atmospheric aging* Some types of lubricants, due to limited compatibility with the polymer, migrate to the surface of the products, causing their stickiness and loss of attractiveness and competitiveness. In many cases, there is also a decrease in mechanical properties. It is obvious that achieving balanced properties by applying one type of lubricant is very difficult.

These shortcomings can be eliminated by preparing a polymer mixture based on the polyvinyl aromatic material according to the invention, which contains as an internal lubricant a combination of isobutyl esters of C-4, a fatty acids and hardened animal fat, the total concentration of these substances in the polymer mixture being 0.5 to 10 parts by weight based on 100 parts by weight of the polymer, and the ratio of the mixture of isobutyl esters of C-4, θΐ6 and C-48 fatty acids to hardened animal fat being 99:1 to 1:99.

UV stabilizers, pigments, antioxidants, flame retardants, blowing agents, and possibly other additives may be simultaneously present in the polymer mixture according to the invention.

Polyvinylaromatic materials are vinylaromatic polymers, especially standard polystyrene, a copolymer of styrene with acrylonitrile, or maleic anhydride.

Tough polyvinyl aromatic material means polystyrene that contains an elastomer as a modifying component.

Tough polyvinyl aromatic materials also include polymers whose basic structural units are simultaneously styrene, acrylonitrile and elastomer, most often polybutadiene or butadiene-styrene rubber. In some cases, part of the styrene may be replaced by alpha-methylstyrene or para-methylstyrene.

Hydrogenated animal fats are products produced by hydrogenation of beef tallow or pork lard followed by glycerolysis. The resulting product has a melting point in the range of 50 to 80 °C.

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A mixture of isobutyl esters is understood to mean a product formed by the esterification of C-^, C-^θ and C ₁₀ fatty acids with isobutanol, with the concentration of Cj.4 fatty acid isobutyl ester being 1 to 7% by weight, C^g fatty acid isobutyl ester being 15 to 65% by weight and C ₁₈ fatty acid isobutyl ester being 30 to 80% by weight.

A lubricating system containing a balanced mixture of isobutyl esters of C^, C-^ and C^g fatty acids and hydrogenated animal fats enables very good strength, rheological, appearance and processing characteristics to be achieved.

The very good properties of the polymer mixture based on vinyl aromatic material prepared according to the invention are demonstrated in the examples given. A summary of the achieved physical and mechanical characteristics is given in the table.

Example 1

No lubricant combination was added to the suspension prepared standard polystyrene intended for injection molding. The material was granulated on a laboratory extruder with a screw diameter of 45 mm and a screw length of 28 D. The temperatures in the individual zones of the extruder were:

1st zone 150 °C 3rd zone 180 °C

2nd zone 170 °C 4th zone 200 °G

The temperature at the extruder head was 180 °C,

Selected properties of the prepared material are listed in the table.

Example 2

3 parts by weight of medicinal oil were added to the suspension prepared standard polystyrene intended for injection. The mixture was homogenized in a high-speed mixer.

236 331 and granulated under the conditions given in Example 1. The results of the measurements of the monitored properties are given in the table.

Example 3

A combination of 1.5 parts by weight of a mixture of isobutyl esters of fatty acids C₁₀, and 1.5 parts by weight of hardened animal fat was added to the standard polystyrene prepared in suspension. After homogenization in a high-speed mixer, the mixture was granulated under conditions as in Example 1. The properties of the material thus prepared are given in the table.

Example 4

No lubricant was added to the suspension-prepared high-impact polystyrene intended for injection molding. The material was granulated under the conditions given in Example 1. The values of selected properties are given in the table.

Example 5

3 parts by weight of stearic acid amide were added to the suspension-prepared high-impact polystyrene intended for injection molding. After homogenization in a high-speed mixer, the mixture was granulated under the conditions given in Example 1. The values of the monitored properties are given in the table.

Example 6

A combination of 1.5 parts by weight of a mixture of isobutyl esters of C1, C2 fatty acids and 1.5 parts by weight of hardened animal fat was added to the suspension-prepared high-impact polystyrene intended for injection molding. After homogenization in a high-speed blender, the mixture was granulated under conditions as in Example 1. The values of the monitored properties are given in the table.

Example 7 236 331

No lubricant was added to the ABS polymer powder intended for injection molding. The polymer powder was granulated on a laboratory extruder with a screw diameter of 45 tur and a screw length of 28 D. The temperatures in the individual extruder zones were:

1st zone 160 °C 3rd zone 198 °C

2nd zone 180 °C 4th zone 220 °C

The extruder head temperature was 200 °C. The values of the monitored properties are given in the table.

Example 8

3 parts by weight of medicinal oil were added to the ABS polymer powder intended for injection molding. After homogenization in a high-speed mixer, the mixture was granulated under the conditions specified in Example 7. The properties of the obtained product are given in the table.

Example 9

2.5 parts by weight of a mixture of isobutyl esters of fatty acids ^14' ^16 ^and θ18 ^and a part by weight of hardened animal fat were added to the ABS polymer powder intended for injection molding.

After homogenization, the mixture was granulated under the conditions given in Example 7. The properties of the product obtained are given in the table.

Example 10

To the ABS polymer powder intended for injection molding, 2 parts by weight of hardened animal fat and 1 part by weight of a mixture of isobutyl esters of fatty acids G^, C-^ and 0 _1β were added. After homogenization, the mixture was granulated under conditions similar to those in example* 7. The properties of the material thus prepared are given in the table.

Example 11

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To the ABS polymer powder intended for injection molding, 0.4 parts by weight of hardened animal fat and 0.6 parts by weight of a mixture of isobutyl esters of C^, G-^g and Ο^θ fatty acids were added.

After homogenization, the mixture was granulated similarly to Example 7. The properties of the prepared material are given in the table.

Table

example no. impact strength (kJ.m ² ) melt flow index (g/10») gloss Ί0 1 15 8.2 2 17 12.4 - 3 25 14.8 - 4 60 4.5 6 5 75 6.2 8 6 90 7.1 15 7 105.5 11.9 37 8 100.5 12.8 40 9 124.5 19.1 58 10 125 20.8 65 11 110 14.1 55

Note:

Impact strength was determined according to ČSN 64 0612, melt flow index according to ČSN 64 0861, gloss according to the modified standard TGL 34087/06 - method C.

The very good properties of the mixtures prepared according to the invention are documented by the values of Examples 3, 6, 9, 10 and 11.

Claims (1)

Mixture based on polyvinyl materials, characterized in that the internal lubricant comprises a combination of a mixture of fatty acid isobutyl ^ C, ^ Ο- θ ^c iq ^and hydrogenated animal fat, wherein the sum concentration of these substances in the polymer composition is 0.5 to 10 parts by weight based per 100 parts by weight of polymer and the ratio of the mixture of isobutyl esters of fatty acid C ^, and _C18 to hardened animal fat is 99: 1 to 1: 99 ·