DD296323A5 - METHOD FOR STABILIZING POLYOXADIAZOL AGAINST PROMISES AND PROCEDURES - Google Patents

Abstract

The invention relates to a method for stabilizing polyoxadiazole Versproeden and Verfaerben. The process is used in the chemical and light industry for the stabilization of Polyoxadiazolfaser- and -formstoffen against the photolytically, oxidatively, photooxidatively, thermooxidatively acting Einfluszgroeszen triggered polymer degradation. The stabilization reactions are achieved by the use of * applied after preparation, before processing, or before use of the polyoxadiazole material. With the stabilization of the polyoxadiazole products, special properties for processing and applications are gradually and temporally improved, thus expanding the possibilities of use. {Chemical industry; Light industry; polyoxadiazole; embrittlement; discoloration; Stabilization process; stabilizers; Tetramethylpiperidine derivatives}

Description

Field of application of the invention

The invention relates to the stabilization of polymeric compositions based on polyoxadiazole and from these obtained fibers, silk, films and other moldings after their preparation, processing or prior to their application to inhibit or inhibit embrittlement and discoloration, so that the processing and To improve application behavior, to increase the utility of Polyoxadiazolmaterialien.

Characteristic of the known state of the art

As is known, polymeric materials of polyoxadiazole tend to degrade during storage, processing and application under the influence of light, with or without oxygen or other oxidants and heat. First, discoloration and embrittlement usually occur. This leads to a deterioration of the processing behavior and the application properties.

The decomposition effect to which the polyoxadiazole materials are subjected is usually limited by incorporation or application of low molecular weight or polymeric substances.

Known is the incorporation of low molecular weight compounds such as N-Salicylidensalicylsäurehydrazinderivaten in polyoxadiazole against degradation upon weathering, i. on exposure to light, air, water (JP-PS 48071455).

It has already been proposed a coating of protective layers of polymeric and low molecular weight substances, such as epoxy resin in combination with other organic components, of organic solvent on polyoxadiazole against degradation by light and oxidation (WP D06M / 3267163).

The above-mentioned substances, also their use in the form of suitable combinations with each other, allow the stabilization of the polyoxadiazole, which is also acceptable in practice, but can not fully satisfy, e.g. in terms of discoloration, migration and abrasion behavior of the stabilizers themselves or their reaction products. This limits the efficiency and the duration of action of the stabilizers and finally the stabilization of the polyoxadiazoles.

Object of the invention

The aim of the invention is the stabilization of Polyoxadiazolmassen and produced therefrom fibers, silks, films and other form bodies against embrittlement and discoloration during storage, processing and application.

Explanation of the essence of the invention

The object of the invention is the development of an economical and ecological process for the stabilization of polymer compositions based on polyoxadiazole and of fibers, silk, films and other molded articles obtained after their preparation, processing or prior to their application in order to inhibit embrittlement or discoloration or To inhibit and thereby obtain characteristic properties longer according to the conditions of processing and applications or to increase the utility value.

According to the invention the object is achieved in that 4-hydroxy-2.2.6.6-tetramethylpiperidine or its esters with mono- and dicarboxylic acids having 1 to 4 carbon atoms and / or 4-amino-2.2.6.6-tetramethylpiperidine or its amides with mono- and dicarboxylic acids with 1 to 4 carbon atoms, either in pure form or as mixtures as stabilizers.

Esters and amides of mono- or dicarboxylic acids having 1 to 4 carbon atoms are particularly effective. Preference is given to the amides or esters with acetic acid and oxalic acid.

Depending on the requirements of the technological conditions and the field of application, it may be expedient to apply the stabilizer or the stabilizer combination by powdering, spraying in a dipping or exhausting from aqueous phase at temperatures of 293 to 343 K without or with further processing aids. It is also possible to use colored polyoxadiazole materials.

The composition of the stabilizer combinations depends on the requirements of the polyoxadiazole materials.

The use concentrations of the stabilizers are 0.1 to 12 parts by weight in%.

embodiments

The invention will be explained in more detail with reference to exemplary embodiments.

example 1

A prepared polyoxadiazole silk 100000f 1000 is treated in an aqueous solution containing 10% by weight of 4-amino-2.2.6.6-tetramethylpiperidine in% as follows: "introduction of the silk into the solution at 293K; Heating the solution of undisturbed motion of the silk in 15 minutes to 338 K; another 15 minutes treatment of the moving silk in the solution at 338 K; Remove the silk from the solution and dry the silk in air at room temperature. The stability of the so treated silk is tested in a xenotester at 303K and 67% relative humidity. Table 1 shows the exposure tearing force ratio (ratio of the tearing strength of the unexposed silk to that of the exposed silk) f _{B of} the unstabilized compared to the stabilized silk after 20h exposure.

Table 1

Polyoxadiazole silk fine%

without stabilizer 18

with stabilizer 39

Example 2

An unprepared polyoxadiazole silk 10Otex f 1000 is treated in an aqueous solution containing 10% by weight of 4-hydroxy-2.2.6.6-tetramethylpiperidine in% as follows: "introduction of the silk into the solution at 298 K; Warm the solution with constant movement of the silk in 15 minutes to 343 K; Treating the silk under its constant motion for a period of 15 minutes with the solution at 343 K; Remove the silk from the solution and dry the silk in air at room temperature. "

The stability of the so treated silk is tested in a xenotester at 303K and 67% relative humidity. Table 2 shows the exposure tearing force ratio f _{B of} the unstabilized silk compared to the stabilized silk after 20h exposure.

Table 2

Polyoxadiazole silk f _B in%

without stabilizer 17

with stabilizer 41

Claims (7)

1. A method for stabilizing polyoxadiazole against embrittlement and discoloration, and from these obtained fibers, silk, films and other moldings after their preparation, processing or prior to their application, characterized in that as stabilizers 4-hydroxy-2,2,6,6-tetramethylpiperidine or its Esters with mono- and dicarboxylic acids having 1 to 4 carbon atoms and / or 4-amino-2.2.6.6-tetramethylpiperidine or its amides with mono- and dicarboxylic acids having 1 to 4 carbon atoms either used in pure form or as mixtures. 2. The method according to claim 1, characterized in that one works in an aqueous solution. 3. Process according to claims 1 and 2, characterized in that one works continuously in the dipping process. 4. Process according to claims 1 and 2, characterized in that it is carried out batchwise in the exhaust process. 5. Process according to claims 1 to 4, characterized in that is worked at 293 to 343 K. 6. Process according to claims 1 to 5, characterized in that colored polyoxadiazole materials are used. 7. Process according to claims 1 to 6, characterized in that the stabilizers are applied without or with further suitable auxiliaries, such as antistatic agents, complexing agents, quenchers and lubricants.