CS267311B1 - Non-dusting rubber chemicals granulate - Google Patents

Abstract

The aim of the solution is to improve the finalization and processing properties of granular chemicals while maintaining their very good dispersibility in rubber mixtures and at the same time simplify and economically benefit the finalization technology of these products. The stated purpose is achieved by adding a viscous, swelling or other modified starch or dextrin as a molding additive to powdered rubber chemicals in the presence of water with subsequent granulation by any of the known methods and drying the product

Description

EN 267 311 B1 1

The invention 8 relates to a non-dusting rubber chemical granulate with a very high dispersibility (agitation) in rubber mixtures and to a process for its preparation.

Tinalizing and epaerological properties (mainly dustiness, flow and handling properties) of rubber chemicals in powder form, such as thiazole and dithiocarbamate accelerators, vulcanization inhibitors, antidegradants, dyes and fillers, are improved by granulation but by powder coating. and the granular product. Suitable a-dies and their application methods are described for powder coating. For example, 2 to 5% by weight of rubber chemicals are recommended. mineral oils. Similar uses have silicone or alkylbenzenes. They are applied by adding to the suspension! product, by mechanical mixing with the powdered product, optionally by spraying. While these additives reduce the permeability of the products, they also enhance the adhesion of the products to metallic and other surfaces. This is removed by combining these additives with others such as tensides, higher fatty acids, or alkyl ether oils. Granulation of pulverulent rubber chemicals, for example by high pressure molding without additives, is not sufficiently effective by itself and is accompanied by the formation of a secondary dust-poor abrasive granulate. The dustiness of the thus prepared products is reduced by similar additions to those used for the powder finals of rubber chemicals, but they do not increase the mechanical strength of grandi. Better mechanical properties can be achieved by granulating rubber chemicals with the presence of binder additives. Several suitable additives with a binding effect and methods of their application are described. In particular, low molecular weight and high molecular weight substances, for example polyvinyl ethers in an amount of 1 to 20% by weight, are recommended. on the dry matter of a rubber chemical, wherein the applied chemical is dissolved in organic water-immiscible solvents to the aqueous suspension chemical. After separation of the water, the product is formed by some of the known methods. The disadvantage of this process is the use of organic solvents and the associated technological and economic demands. For similar use, aqueous emulsions of polyvinyl acetate and aqueous solutions of polyvinyl alcohols have been proposed. The disadvantage of these additives is the high economic demands and poor dispersibility of the prepared granules. These disadvantages are improved by combining said polymeric binders with aqueous dispersions of higher paraffinic hydrocarbons or fatty acid leaches prepared with heat in the presence of surfactants, thereby increasing the technological demands of the process. Additions of natural and synthetic latex latexes have also been proposed. The disadvantage of these additives is the susceptibility of the rubbers to oxidative degradation, which requires the addition of antioxidants. In general, the disadvantage of the additives used is that the effect achieved by them is complex, but will only address some of the product's processing and processing properties. For example, the oil additives reduce the permeability and improve the dispersibility, but do not have a binding effect in the granulation and enhance the adhesion of the products to the metal surfaces. Polymeric additives have suitable properties for grandi forming, but do not adversely affect dispersibility-products when mixed into rubber mixtures and their use is economically demanding. The higher paraffinic hydrocarbons and higher fatty acids have a good form-forming effect on granulation only when they are fired to the granular material, thereby reducing the active ingredient content of the final product and making the application process more technologically demanding.

The above mentioned drawbacks are solved by the solution according to the invention, in that the non-dusting rubber chemicals granules with very good dispersibility are obtained by molding from a powdered rubber chemical by one of the known granulation processes with the addition of 0.5 to 6.0% by weight. Starch to a rubber chemical and in the presence of water in an amount of 5 to 40% by weight. to a mixture of a mixture of rubber chemistry and starch. As starch, various types of native, swelling or other modified starch or dextrin can be used, which are applied by air-dry or dissolved in water (erased) by homogenization with a wet or dry chemical material prior to granulation. After maturation of the resulting mass, the granules are dried and dried to give a water content of 0.1 to 0.5% by weight. Maturation in the aging process of 5 to 15 minutes is mainly required for the application of airborne starch. Depending on the kind of modification, the degree of degradation of starch will be increased by the amount needed to form the grandi, for example, the same effect is achieved by using 2 wt. of swelling starch or-4% by weight of starch; dextrin.

The solution according to the invention is to form at least the amount of primary dust obtained in the granulate formation, the granulate obtained being elastic so that it is not crushed even under extreme conditions of handling and transport. The granulate has a high abrasion resistance, so that the formation of secondary dust is minimized and at the same time exhibits very good dispersibility when mixed into rubber mixtures. starch, as an additive to rubber chemicals, is more effective than other additives, for example, the properties of a granulate comparable to using 256 wt. of swelling starch by using 4 to 56 wt. higher paraffinic hydrocarbons may be fatty acids. This means that the use of starch minimizes the reduction of the active substance content in the final rubber chemicals form, the advantage of the present invention being that very little dissolution of the content of the granulate required by other additives is required.

The advantages of the described solution also include economic advantageousness, technological disadvantage of the preparation of the additive and its application, non-toxicity and work with the water environment. Example 1

25 kg of technical M-cyclohexyl-2-benzothiazolsulfonamide (Sulfenax CB / E) having a moisture content of 24 wt. While stirring, 430 g of air-swelling starch with a moisture content of 10% by weight are added. After 10 min. by homogenization, the resulting paste is pressed through the molding matrix and granulated in a rotating tilting drum. The resulting granulate, dried at 70-80 ° C, has a cylindrical particle diameter of 1.5 to 2.5 mm and a length of 3-4 mm and a moisture content of 0.3% by weight. The dust content of the granulate is below 1556 wt. and dispersibility very good. Example 2

19 kg of technical 2-mercaptobentiazole (PneumaxMBT) in a dry powder state is introduced into the homogenizer. A solution prepared from 950 g of dextrin by suSin90 56 wt. and 6,000 ml of water. After homogenization, the granulate is prepared as in Example 1. The dust content of the granulate is up to 15% by weight. and dispersibility very good. Example 3 9.5 kg of technical H-cyclohexylthiophthalimide (Duslin) with 9.5 kg of technical calcium carbonate are mixed in a homogenizer and 430 g are added under stirring.

Claims (1)

Non-dusting granulate of rubber chemicals with very good dispersibility, characterized in that it contains 93.5 to 99.4% by weight. rubber chemicals techniekej Purity 0.5 to 6.0% by weight. native, swellable or other modified starch or dextrin 0.1 to 0.5 wt. water.