SU914584A1 - Composition for producing foamed plastic - Google Patents

Description

The invention relates to expandable compositions based on a copolymer of acrylic acid nitrile, polybutadiene and styrene (ABS copolymer), which can be used in the preparation of products that mimic wood.

Polymer compositions are known in which Ν, L'-dinitrosopentamethylenetetramine, 2,4,6-trihydrazine-1,3,5-triazine are used as a blowing agent [1].

However, the decomposition products of these compounds contain ammonia, which promotes the degradation of the polymer and causes corrosion of the metal parts of the equipment of the processing equipment.

Closest to the proposed composition and the achieved effect is a composition for the preparation of foam, including Acrylonitrile-butadiene styrene copolymer and a blowing agent, which contains azodicarbonamide as a blowing agent. Azodicarbonamide is administered in an amount up to 5 May. hours in different grades of copolymer ABC. Depending on the purpose of the composition, various types of plasticizers, stabilizers and fillers are used [2].

2

However, during the thermal decomposition of azodicarbonamide, cyanuric acid is released, which causes corrosion of the metal parts of the equipment of the processing equipment.

5 The aim of the invention is to reduce the toxicity of the composition and the intensification of the process.

This goal is achieved by the fact that in the composition to obtain a foam, including acrylonitrile-butadiene-styrene copolymer and a blowing agent, is introduced as a blowing agent 5-acetylaminetetrazol in the amount of 0.2—1.0 May. hours at 100 May. including polymer.

The proposed blowing agent has 15 the following structural formula:

(ΉιϋΟ-ΝΗ-С-ΝΗ II I N N

20 ^X

²⁰ N

It is obtained by acylation of 5-aminotetrazole with acetic acid in the presence of sodium acetate. The method of obtaining is technologically simple, based

3

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four

on the use of industrial raw materials aminoguanidine and acetic acid. The decomposition temperature of the specified blowing agent is 274 ° C. The decomposition of 1 g of the substance releases 202–210 ml of nitrogen.

Examples 1-4 (control). The components of the ABS copolymer (TU6–05–1587–74) and the blowing agent are mixed in an appropriate amount. The mixture is loaded into the hopper of the extruder laboratory machine and extruded under the following process parameters.

Speed of rotation of the screw, rpm 60

Cylinder temperature by zone, ° С

loading area 220

plasticization zone 240

extrusion zone 280

Indicators of the quality of the foam obtained are the apparent density (GOST 409-68) and the visual characteristics of the porous structure (Table 1).

As follows from the table. 1 data, with equal dosage of pore-forming agents, the apparent density is lower for the foam obtained with the use of 5-acetylaminotetrazole.

Examples 5-14 (control).

An ABS copolymer composition is prepared with an appropriate amount of a blowing agent by mixing the components in a mixer for 30 minutes (Table 2).

Foamed plastics with a size of 160 X 80 X 8 mm are made from the resulting composition by injection molding, after which the apparent density of the foam is determined (GOST — 409-68); breaking stress under tension (GOST 11262-76); breaking stress4 under compression (GOST 4651-68); impact strength (without notching) (GOST 4647-69); the nature of the porous structure (visually); color (visually) and smell of the sample (organoleptically).

₁ In table. 3 shows the quality indicators of the injection molded foam material.

Color samples light.

The data table. 3 show that the 5-acetyl "5 tilaminotetrazol exhibits blowing effect on the level of applied -to industry azodicarbonamide blowing agent, but in contrast to it practically causes no corrosion of the metal parts ²⁰ snap processing equ been concerned.

So, when using azodicarbonamide on the working parts of the equipment snap-in, after the first casting, a plaque is formed, which must be removed, as a rule, manually after each operation. With the use of 5-acetylaminotetrazole, the cleaning operation is carried out every 50 castings.

As a result of the tests, it was found that the new foaming agent is well combined with the polymer main one, does not affect its initial physicomechanical properties.

) Tabl and c a 1 Example No Composition The content of components, parts by weight Apparent density, kg / m ^ The nature of the porous structure one ABS-2 5-Acetylaminotetrazole 100 0.25 818 Uniform finely porous 2 ABS-2 100 5 * + 7 Also 5-Acetylaminotetrazole 0.5 3 ABS-2 100 900 - and _ Azodicarbonamide 0.25 four , ABS-2 100 615 - and- Aedicarbonamide 0.5

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table 2

Components The content of components in the compositions, parts by weight, according to examples ¹ 1 ² 3 four five 6 7 eight 9 ten ABS copolymer stamps ABS-2020 100 100 100 100 100 100 100 100 100 100 5-Acetyl Notetrazole 0.2 0.4 0.6 0.8 1.0 Azodicarbonamide ^ CHHZ-21) 0.2 0.4 0.6 0.8 1.0

Table 3

Indicators

Examples

one ² I 3 four five 6 | 7 eight 9 Apparent density, kg / m ³ 992 828 790 718 645 964 907 874 740 Destructive stress under tension, kgf / cm ² 336 235 197 168 129 zoo 298 250 170 Breaking stress in compression, kgf / cm ² 401 334 to 282 288 211 361 304 283 208 Impact strength, kgf cm / cm ² 34.0 26.7 22 18.7 16,1 30.5 27.9 26.1 20

ten

Character

structures

Sample odor

Fine-meshed

Moderate

Fine-meshed

Unpleasant

Claims (1)

Claims composition for foam, including acrylonitrile-butadiene-styrene- ⁵⁵ copolymer and a pore-forming agent, characterized in that, in order to reduce the toxicity of the composition and intensify the process, it contains 5-acetylaminotetrazol in the following ratio of components, May. including: Acrylonitrile-butadiene styrene copolymer 100 5-acetylaminotetrazole 0.2—1.0 7 914584 eight cl.