DE746081C - Process for improving the heat resistance of high-polymer substances containing halogen - Google Patents

Description

Process for improving the heat resistance of high polymers Halogen-containing substances It is well known that high-polymer substances containing halogen have a tendency the heat easily to split off hydrogen halide. This causes discoloration of the fabrics one, and the hydrogen halide attacks metals that are involved in the processing of the substances can be used, e.g. B. rolling or pressing, and also metal parts in finished moldings at. ° To prevent this elimination of hydrogen halide in the heat, one has already proposed to use lead compounds as a heat stabilizer. Unsatisfactory but is, however, the toxicity of lead compounds and their tendency, in particular to discolor even in the presence of small amounts of hydrogen sulfide.

It is also known to use alkaline substances, e.g. B. alkali salts of weak organic acids, carbonates or Hy droxes of alkali or alkaline earth metals or weakly alkaline nitrogen-containing organic compounds such as guanidine, diphenylguanidine, triethanolamine and mono- and dibenzylamine to use as stabilizers. These substances immediately absorb the hydrogen halide that is split off in the heat and neutralize it. At the same time, however, they have an effect on processing. many high-polymer substances containing halogens in the heat due to their alkaline reaction acceleration of the hydrogen halide release so that in these cases' tAht succeeds completely colorless moldings herzü * elxeri. Remote urea and ThidiariAstri & as Suggested stabilizers. Aü # 9i this verse ties do not prevent themselves on their own a brown coloration when the high-polymer, halogen-containing substances are processed in the heat.

It has now been found that there is a substantial improvement in the Heat resistance of high-polymer halogen-containing substances achieved when alkaline acting agents and also amines or carbamides, which are mobile, by alkali have replaceable N \ Tasserstofiatom, added as a stabilizing agent.

Alkali and alkaline earth hydrides are considered to be alkaline agents and carbonates and salts of weak acids, especially organic acids or boric acid, also called basic salts of phosphoric acid.

Suitable amines or carbamides with at least one alkali metal Replaceable hydrogen atoms are, for example, diarylamines, such as diphenylamine, also Thiourea and especially arylthioureas, e.g. B. phenyl, diphenyl, dichlorodiphenyl, Ditolyl and Dinaphtüclthioureas and also aryl ureas and t_ "reide.

High polymer halogen-containing substances, which are stabilized according to the invention are, for example, chlorinated rubber, polyvinyl chloride, chlorinated Polyvinyl chloride, Polt 'dichlorethylene, polychloroacrylic compounds and 1lisclipolymerisate from the monomeric compounds on which these polymers are based or with other polymerizable substances. ., Even when mixed with plasticizers The beneficial stabilizing effect of the mixture of polymers expresses itself alkaline substances with the amines or carbamides mentioned.

The halogen-containing high polymer stabilized according to the invention Fabrics are also quite resistant to long exposure to heat. The alkaline ones Means also take the hydrogen halide which is split off in the heat and neutralize it, but at the same time becomes evident through the addition of a Ainins or carbamides of the type mentioned reduce the alkaline effect of these agents.

The amount of alkaline agents and amines or carbamides can vary within wide limits. In general, additions of o, i are recommended up to 1 °, (o in alkaline agents and those from o, oi to .1. ° # 'p in amines or carbamides. There is a specific one for every high polymer substance containing halogen Ratio of stabilizing agents in which they have the most lasting effect. This relationship can easily be established through experiments.

The stabilizing agents can be in solution or suspension or else added as a powder to the high-polymer substances containing halogens «-erden. these can present in dispersed or solid form. Mostly it is expedient for a distribution that is as even as possible before the high polymers are processed To take care of halogen-containing substances, but the stabilizers can also only during this processing, for example when four-rolling or 'blackmailing or other processing in the heat. You can also use the stabilizers even during the production of the halogen-containing, high-polymer substances such. B. at the polymerization, add.

Due to the improvement in durability achieved according to the invention of high-polymer halogen-containing substances against the effects of heat, it is possible now to produce completely colorless objects from these materials by heat deformation, while so far only more or less discolored moldings were obtained from them. Example 1 100 parts each of a polyvinyl chloride with a high degree of polymerization, obtained by emulsion polymerization are, after precipitation with Washed soda solutions of various concentrations, so that the Polvinerisat each Contains the desired amount of soda specified in the table below. The dried one Polyinerisat "ground on this about i °, @ o` dachs as a lubricant and various Amounts of diphenylthiourea added in the ball mill. The individual samples are rolled for 1/4 hour at 165 'and finally to an o.i mm thick film moved out. This is then heated to 155 'in a heating cabinet for 2 or 1 hours. The resulting coloration gives a measure of the heat resistance of the film.

The test results compiled in the following table show the effect of different amounts added. The numbers in columns to f correspond to the color of the 8-fold folded foils and mean: i = completely colorless, 2 = discoloration just visible, 3 = slightly light brown or light yellow, i.e. = light brown, stronger brown, ö = strong brown, = almost dark brown, dark brown. 9 = black-brown. The designation clear in the table means that the films have a particularly beautiful clarity and the clarity of the other films abcdef Additions in% of discoloration of the foils after Approach diphenyl rollers at and storage at i55 ° Soda thiourine 105 '-----, - Fabric i5 minutes z hours, 4 hours I less than 0.03 0/0 0 3 to 4 7 7 to 8 0.03 0/0 0.03 3 to 4 7 to 8 8 3 0.030 /, I, 0 4 7 to 8 o, o8 0 / ö 0.0o6 2 6 to 7 7 5 o, o8 0/0 o, oi I 6 to 7 7 6 0.080 /, 0.03 I (clear) 6 7 to 8 7 0.080 / 0 . 0, I5 I (clear) 7 8 8 o, o8% 1, 0 I 8 9 9 0.2 0/0 0 3 6 6 to 7 I 0 0.2 0/0 0.03 I to 2 4 5 1I 0.2 0/0 0, I5 I (clear) 2 5 I2 0.2 / o I, 0 I 2 5 I3 0.4% 0 3 to 4 5 5 to 6 I4 0.4 0/0 0.03 I to 2 5 to 6 6 I5 '0.4 0/0 0, I5 I (clear) 3 to 4 6 16 0.4 0/0 1.0 II to -2 yellowish 5 17 0.4 0/0 3.0 I to 2 2 yellowish 3 to 4. yellowish 18 0.4 0/0 5.0 I to 2 I 2 to 3 yellowish 3 to 4 yellowish The table shows the influence of the additives alone and together. The effect of the two additives is not purely additive, but the effect of the soda additive is greatly increased by the addition of diphenylthiourea. For example, in batch 5 with 0.08 010 soda, the addition of 0.0 oz 0/0 diphenylthiourea achieves a far more favorable effect than with batch 3 by adding a larger amount of diphenylthiourea because there is less, namely only 0.03 'f' 0 soda are added. The table further shows that β for each amount of soda the best effect and greatest clarity is achieved with a certain amount of diphenylthiourea, and that a further increase brings about a significant deterioration in stability. For example, batch 6 with 0.08.0% soda content tends to have the best effect at 0.030-0.0 diphenylthiourea, which worsens again when 1% diphenylthiourea is added (test S).

In contrast, samples 16 and 17 are in the series with 0.4% soda content with r up to 3 0, (o Addition of diphenylthiourea the best. Samples according to approach 16, which even after 2 hours of storage up to 155 °, practically none including the without diphenyl thiourea additive. Show discoloration are suitable particularly suitable for the production of colorless moldings during or after their production are subjected to a particularly strong action of heat.

The diphenylthiourea can also be added instead of in powder form in the form of solutions, e.g. B. in methanol, or in aqueous suspension. So can e.g. B. the precipitated polyvinyl chloride can be washed with a soda solution, which is saturated with diphenylthiourea. In this case too, one obtains after a colorless film for more than 15 minutes of rolling at r65 °. Here is the distribution of the stabilizer particularly evenly, which has the effect that one A beautiful, uniform film is obtained after r to 2 rolling passes. Similar to the diphenylthiourea also have a number of other arylated thioureas, so z. B. dinaphthyl, ditolyl, dichlorodiphenyl and phenylthiourea. The phenylthiourea Due to its easy solubility in water, it is special for addition in aqueous solution suitable.

A similarly beneficial effect is also evident in the case of copolymers Vinyl chloride and maleic acid esters or acrylic acid esters or at Mixtures of these copolymers with polyvinyl chloride with the addition of o, 2 to O.4% soda and o, a5 to i, o ° / ° diphenylthiourea achieved.

EXAMPLE 2 100 parts of the polyvinyl chloride used according to Example 1 are washed out with aqueous solutions of soda and thiourea which are so concentrated that, after drying, the polyvinyl chloride contains the amounts of these substances given below. The polyvinyl chloride is then rolled into a film according to Example i and tested for its heat resistance. The results are compiled in the following table: abcdef Additions in °; o from discoloration of the foils after approach Soda Thiourine_ Rolling at and storage at 1.55 ' fabric 5 IS minutes 2 hours 4 hours 1 less than o, o3 ° 1 ° 0 4 to 5 7 7 to 8 2 0.03 ° f0 o, oo6 4th to 5 i 7 to 8 7 to 8 3 0.0311 / 0 o, OI 4 7 to 8 7 to 8 4 0.03%; 0.03 2 to 3 a6 to 7 7 5 0.03 0/0 0, 1 5 3 7 8 6 0.03 °% 1 , 0 3 to 4 8 9 7 0.080 / 0 0 3 6 7 8 0.080 /, o, oo6 i to z 6 7 9 0.080 /, o, oi 1 5 - io, 0.080 / 0 0.03 1: (clear) 4-7 11 0.08% 0 °, 1 1 5 (clear) 7 8 12 0.08 ° /, 1, 0 ! 8 9 13 0.2 0/0 0, 006 1 to 2 _ 6! 6th 14 0.2 °% 0.01 1 I 6 6 to 7 i5 0.2 °% 0.03 1 (clear) 3 7 16 0.2 ° / 0 o, is z (clear) 6 to 7 8 17 012 0/0 1, 0 1 6 to 7 8 to 9 18 0,4 ° / oo, oo6 1 6! 6 to 7 z9 0> 4 ° / oo, oi i (6 7 20 0.4 ° / ° 0.03 1 2 3 to 4 2z 0.4 ° / 0 0, i5 i (clear). "2 j 22 0, -1 0/0 1, 0 1 to z I 3 The table shows that the thiourea has a similar effect in terms of initial stability as approximately the fold amount of diplienylthiolarea, while the long-term stability achievable with thiourea is somewhat lower than that with diphenylthiolarea.

Example 3 100 parts of the polyvinyl chloride used according to Example 1 be with a solution of 2.6 parts of a mixture of secondary and tertiary Sodium phosphate made into a paste in 30o parts of water, the p $ i of which is. After your suction, the poly viny lchlorir_i is dried, with i part wax and 0.15 parts of thiourea mixed in a ball mill and then mixed at 165 ° to one Pre-rolled foil. The film is completely colorless after more than 15 minutes of rolling, while a film without thiourea shows a red-brown coloration. An addition of 0.5 parts of diphenylthiourea instead of thiourea gives a similar result favorable effect.

Example 4 100 parts of the polyvinyl chloride used according to Example i are mixed with i part sodium stearate and i part diphenylthiourea and pre-rolled at 165 ° to form a film. The film obtained in this way is practically colorless and results even after further heating at z55 ° a less brown coloration as a film produced in the same way. without added diphenylthiourea shows after 1% 4 hours of rolling.

Claims (1)

PATENT CLAIM: Process for improving heat resistance of high-polymer halogen-containing substances, characterized in that they are small amounts of an alkaline substance and an amine or carbamide with a mobile hydrogen atom, which can be replaced by alkali, as a stabilizing agent clogs. To distinguish the subject of the application from the state of the art, im No pamphlets were taken into account. `