PL163320B1 - Method of obtaining burning retardation agents for use as additives to polystyrene and abs material - Google Patents

Abstract

Method of producing polystyrene flame retardant concentrates and acrylonitrile-butadiene-styrene terpolymer, characterized in that the flame retardant composition is in synergistic form a mixture of decabromodiphenyl ether and antimony trioxide, ranging from 20% to 70% by weight of the concentrate and the compatibilizing agent in the form of brominated aromatic compounds or cycloaliphatic compounds with a melting point below 200 ° C, such as tetrabromobisphenol A, octabromodiphenyl ether or hexabromocyclododecane, used in an amount from 0.5% to 3.5% of the concentrate weight is mixed in a mixer with the base material that is used is polystyrene or acrylonitrile butadiene styrene terpolymer used in a make up amount 100% by weight of the concentrate, and then the resulting mixture is carried out by heating into a homogeneous mass, which is then extruded and granulated.

Description

The object of the invention is precisely to solve the problem of obtaining a homogeneous concentrate of flame retardants being a synergistic mixture used for polystyrene and ABS material.

The method according to the invention consists in obtaining highly concentrated flame retardants in a base material, which may be polystyrene or ABS material.

The synergistic mixture can be used in various weight ratios of the components, the most preferred composition being a weight ratio of 2 to 4 parts decabromodiphenyl ether to 1 part antimony trioxide.

The flame retardants are mixed with the base material, heated and then extruded and granulated. The most serious difficulty of the process is to obtain a highly concentrated mixture with homogeneous properties, so that the obtained granulate does not break down into the starting components of the mixture and is easily further homogenized in the processed material.

It was surprisingly found that a small addition of aromatic or cycloaliphatic bromine derivatives with a melting point below 200 ° C, such as tetrabromobisphenol (mp 180 ° C) or octabromodiphenyl ether (mp 125-165 ° C) or hexabromocyclododecane (mp. 180-190 ° C), it fulfills the role of a binding agent, allowing to obtain concentrates containing up to 70% of flame retardant compositions.

The invention is illustrated without limiting its scope as follows:

EXAMPLE 1 A mixture of raw materials of a size is dosed into a Werner-Pfleiderer mixer

composed of: Polystyrene - 61.7 parts wt. Decabromodiphenyl ether -25.0 "" Antimony trioxide - 10.0 "" Tetrabromobisphenol A - 3.0 "" Calcium stearate - 0.3 ""

These raw materials are mixed for about 30 minutes, taking advantage of the electrification of polystyrene, which causes the flame retardants to stick to the polystyrene granules.

From the mixer, the raw materials are transported by pneumatic transport to the extruder hopper. Flame retardant concentrate granules are obtained in a one-stage technological process, using an extruder with a sufficiently long plasticization zone of the material, enabling the homogenization of molten polystyrene with flame retardants. The temperatures of the extruder heating zones are below 200 ° C.

The homogenized mass is extruded in the form of a bar, cooled in a stream of cold air, and then crushed in a granulator.

Example II. A mixture of raw materials composed of: ABS-tcrpolymer acrylonitrile /

Butadiene / styrene - 57.7 parts wt.

Decabromodiphenyl ether - 22.0 ""

Antimony Trioxide - 12.0 ""

Octabromoddenyl ether - 1.0 ""

Calcium stearate - 0, 3 ""

The mixer feed is mixed for about 30 minutes, then the raw materials are fed to the extruder hopper by means of a pneumatic conveyor. Homogenization and grinding of the obtained concentrate is performed as in Example 1.

Publishing Department of the UP RP. Circulation of 90 copies. Price: PLN 10,000

Claims (2)

Patent claims 1. The method of producing concentrates of polystyrene flame retardants and acrylonitrile-butadiene-styrene terpolymer, characterized in that the composition of flame retardants in the form of a synergistic mixture of decabromodiphenyl ether and antimony trioxide, constituting from 20% to 70% of the concentrate and brominated aromatic homogenizing agent or cycloaliphatic with a melting point below 200 ° C, such as tetrabromobisphenol A, octabromodiphenyl ether or hexabromocyclododecane, used in an amount of 0.5% to 3.5% of the concentrate mass, are mixed in a mixer with the base material, which is polystyrene or terpolymer Acrylonitrile-butadiene-styrene is used in an amount to make up 100% of the concentrate mass, and then the resulting mixture is heated into a homogeneous mass, which is then subjected to extrusion and granulation. 2. The method according to p. The process of claim 1, wherein the weight ratio of the components of the synergistic mixture is 2-4 parts decabromodiphenyl ether to 1 part antimony trioxide. In consumer products containing details of polystyrene and ABS (acrylonitrile-butadiene-styrene terpolymer), it is necessary to use these materials in a flame-retardant version. Polystyrene is one of the most easily flammable plastics. The oxygen index of this material is about 18% and the heat of combustion is approximately 4 × 10 ⁸ J / kg (for pine wood 20% and 1.8 × 108 J / kg, respectively). The oxygen index of ABS terpolymer, usually containing more than 50% of bound styrene, is 18.3-18.8%, depending on the copolymer content. Among the flame retardants used for polystyrene plastics, bromine-containing compounds are the most important. In order to obtain polystyrene with self-extinguishing properties, it is necessary to introduce such an amount of additives that the bromine concentration in the material is 4-10%. Bromoaromatic compounds are especially suitable for use as flame retardants in plastics processed at temperatures of 220-240 ° C. They are effective in the presence of antimony trioxide or organophosphorus compounds. Good flame retardant effects of polystyrene and ABS material are obtained when using a synergistic flame retardant composition consisting of a mixture of antimony trioxide and decabromodphenyl ether. The technical solution to the problem of reducing the flammability of polystyrene and ABS plastic can be achieved in two ways: - by introducing an appropriate amount of modifiers, i.e. flame retardants, at the stage of production of a polymeric material, thus achieving a certain class of its flammability, without the possibility of further affecting this property of the material, - by producing concentrates containing flame retardants in the base material in a concentration many times exceeding the amount needed to obtain the desired flammability class of the material. Such concentrates are mixed with a standard material in the processing process. The main advantage of the second method is the possibility of obtaining a material with a variable, desired flammability class by introducing an appropriate amount of the concentrate into the base material at the stage of feeding the processing equipment, while its disadvantage is the difficulty of obtaining a homogeneous concentrate with a high content of flame retardants, which will be easily further homogenized in the processed material. plastic. 163 320 It is difficult to obtain concentrates of this composition in polystyrene or ABS, in a concentration that justifies the name "concentrate, because the melt does not wet the flame retardant composition and the forcing process does not produce a homogeneous substance. For example, from the patent description of the Polish People's Republic No. 119 797, methods of obtaining concentrates of other additives to polymers, e.g. antistatic agents, are known, for which the base material is stearin or waxes with a low melting point and good wettability of the concentrated substance. However, in the case of preparation of flame retardant concentrates, this solution is practically impossible due to the increase in flammability resulting from the high flammability of stearin and waxes.