CS266130B1 - Modificator-stability and extract of gaseous effluents - Google Patents

Abstract

The solution is aimed at influencing the physicochemical characteristics of mixtures containing active components of blowing agents I, II or III. The essence is the use of hollow glass beads characterized by a diameter of 0.1 to 500 µm, as modifiers of thermal stability and the extraction of gaseous products, in an amount of 0.5 to 98.0% by weight. per weight of the relevant active component. The solution can be used in the production of blowing agents, or in their application in the production of lightweight rubber and plastic materials.

Description

The invention relates to the use of hollow glass beads as modifiers for the thermal stability and the yield of flue gases in mixtures containing the active ingredients of blowing agents.

Chemical blowing agents, as thermodynamically unstable substances, tend to undergo uncontrollable explosive transformations. Blowing agents based on 1,5-methano-3,7-dinitrose-1,3,5,7-tetraazacyclooctane (codenamed DNPT), depending on the requirements of the production technologies of the rubber industry and the plastics industry, contain 40 to 90% by weight. DNPT. The concentrated blowing agent contains some mineral or other oil or other phlegmatizer to reduce dust and sensitivity to impact. Increasing safety during transport and storage and improving the incorporation into the blended mixture and thus the porous structure of bleached products is achieved by diluting the active ingredient with a neutral inorganic additive such as kaolin, micronized limestone, zeolite, hydrated borax, magnesium oxide, sodium sulfate, hydrated aluminum oxide, hydrated aluminum oxide. urea-formaldehyde condensates and the like.

To eliminate the unpleasant odor produced by thermolysis of DNPT in the process of lightening, especially rubber products, deodorants such as mixtures of methylolureas with methylenebisurea, or also polyols (glycol, glycerin, etc.), or biuret derivatives, vodonone are added to the active blowing agent components. , in particular cross - linked urea - formaldehyde condensates or urea thermolysis products and others. It is possible to use other types of compounds as deodorants, but these cannot be added to DNPT before their use in the coating process, as they have a significant negative effect on the stability of such resulting mixtures, which reduces work safety and increases the risk of fire during storage and use. This also applies to the oldest and so far the most used deodorant when blowing with blowing agents based on DNPT, which is fine-grained urea, respectively. its mixture with polyols and other additives, which is added to the blended mixture separately. When using urea deodorant, urea also diffuses (sweats) to the surface of the product, which negatively affects the aesthetic appearance of the product.

When using azodicarbonamide blowing agents, especially in the rubber industry, or when lightening ethylene-vinyl acetate copolymers, it is desirable to influence the decomposition temperature of this azo compound. This is achieved by the addition of various modifiers, in particular salts of zinc, cadmium and other metals, hexamethylenetetramine, biuret, but also water-insoluble derivatives of urea, 1,5-methane-3,7-dinitrose-1,3,5,7-tetraazacyclooctane, organic phosphates. etc. In addition, technical azodicarbonamide has a negative tendency to agglomerate during storage due to its applicability in the lightening process.

The present invention relates to the use of hollow glass beads characterized by a diameter of 0.1 to 500 [mu] m as modifiers of the thermal stability and flue gas yield of azodicarbonamide, 1,5-methano-3,7-di-nitroso-1,3,5,7- tetraazacyclooctane, 1,3,5-trinitrose-1,3,5-triazacyclohexane, and / or mixtures containing these blowing agent active ingredients, in an amount of 0.5 to 98.0% by weight, based on the weight of the respective active ingredient.

An advantage of the present invention is the technical and economic availability of hollow glass beads. The application of by-product fractions of the balls will increase the economic efficiency of this production due to the advantageous use of the balls, which are a burden for other processing. Other advantages are in particular in increasing the yields of gaseous gases and the thermal stability of the active ingredient of the blowing agent in the polymer mixture, which is important in its pre-processing also in the transmission of low bulk density, which is reflected in the improvement of the porous structure of the layered material, in the reduction of transport costs and in the reduction of the labor in the processing of the blowing agent.

As the modifier, glass beads with a diameter of 0.1 to 500 μm, preferably 20 to 120 μm, and wall depths of 0.1 to 10 μm, preferably 0.5 to 5 μm can be used. The presence of the solid bead fraction does not reduce the desired effect of the modifier. The amount of glass beads applied is usually in the range of 0.5 to 60% by weight, based on the weight of the resulting mixture, and is only

It is exceptionally necessary to cross this limit. The effect of the modifier can be influenced and controlled by the surface treatment of the beads e.g. hydrophilic, conductive, etc.

The invention is further illustrated by the following examples, which, however, do not limit or exhaust the scope.

Example 1

An aqueous solution of water glass and trihydroboric acid is prepared in such a ratio that, after melting, a glass having a composition of 75% by weight of silica, 22.4% by weight of sodium oxide and 2.6% by weight of boric oxide is formed. The solution thus prepared is pneumatically sprayed and conveyed to the burner flame, where at a temperature of 300 DEG C. and a residence time of 0.1 to 0.3 s, the entire process of forming hollow glass beads takes place. The mixture of flue gases and microspheres is separated on a filter device. Beads in the size range of 1 to 150 [mu] m are obtained with a predominance of 20 to 60 [mu] m in size and a wall thickness of 1 [mu] m (bulk density 95 kg.m).

Example 2

Technical 1,5-methano-3,7-dinitrose-1,3,5,7-tetraazacyclooctane (DNPT) with a content of 4.9% by weight is available. 1,3,5-trinitrose-1,3,5-triazacyclohexane (TMTA), azodicarbonamide (ADC), hollow glass beads with hydrophilic treatment in the size range of 20 to 120 μm with a predominance of 70 μm and a wall thickness of 3 to 5 [mu] m (bulk density 90 to 110 kg / m) designated PQ 400 and by-fraction from the production of ethylbenzene (EDE 20). Four samples are prepared from these raw materials.

no. 1 DNPT (anhydrous)

no. 2 DNPT + beads according to Example 1 + EDE 20 (mixed in a weight ratio of 6.5: 2.5: 1) no. 3 DNPT + PQ 400 + EDE 20 beads (mixed in the same ratio as in sample no. 2).

no. 4 ADC + beads according to Example 1 (mixed in a weight ratio of 1: 1).

A modified thermal explosion methodology according to H. Henkin and R: Mc Gill (Ind. Eng. 'Chem. 1952, 44, No. 06 1391 to 95) is DNPT and its mixtures Specified by induction periods of air in the temperature range 190 to 210 ° C. From the values thus obtained, the air energies (E), the extrapolated induction period of the excitation for 150 ° C (Tau lg) and the averaged induction period of air for 190 ° C (Tau _lgQ ) are calculated.

All samples are Specified by Gas Number. The measured and calculated values are represented in Table 1.

Tabulkal ·

Sample no. Activating energy Induction period £ s] Gas number ^Tau 150 ^Tau 190 ⁹ (extra- (spriemero-half)) 1 59.5 213.2 49.5 283.5 2 87.9 3 89.9 636.5 73.6 190.2 668.8 73.7 186.4 4 - - - 166.1

The invention can be used in the production of blowing agents, resp. directly in the production of lightweight rubber and plastic materials. _r

Claims (1)

Use of hollow glass beads characterized by a diameter of 0.1 to 500 .mu.m as modifiers of thermal stability and flue gas yield of azodicarbonamide, 1,5-methano-3,7-dinitrose-1,3,5,7-tetraazacyclooctane or 1 , 3,5-trinitro-1,3,5-triazacyclohexane, and / or mixtures containing these active ingredients blowing agents in an amount of 0.5 to 98.0% by weight, based on the weight of the respective active ingredient.