DE1068012B - Process for the sulfochlorination of low-pressure polymers of ethylene - Google Patents

Description

GERMAN

The sulfochlorination or chlorosulfochlorination of High pressure polymers of ethylene with melting points from 100 to 120 ° C and molecular weights above 2000 is known. High-pressure polymers of ethylene are products that are around Dissolve 60 ° C in various solvents. Your sulfochlorination or chlorosulfochlorination is in solution has generally been described in carbon tetrachloride. It is also known, however, the process steps mentioned in chloroform, trichlorethylene, tetrachloroethane, etc. and, if a low-boiling one Solvent was used to work under pressure and thereby elevated temperatures.

By finding the so-called low-pressure polyethylene, for example manufactured according to the German Patent applications Z 3799 IVb / 39c, Z 3862 IVb / 39c, (German interpretation 1004 810), Z 3882 IVb / 39c, (German Auslegeschrift 1008 916), Z 3941 IVb / 39c, (German Auslegeschrift 1012 460), Z 3942 IVb / 39c, (German Auslegeschrift 1 016 022) and Belgian patent 530 617, a new type of polyethylene has become known, which differs from high pressure polyethylene by a different structure. Due to the lack of the the branches characteristic of high-pressure polyethylene have a much higher so-called crystalline part. One consequence of this is the completely different solubility properties of low-pressure polyethylene .

Because of the low solubility of the so-called low-pressure polyethylene, it has therefore been proposed the low pressure polyethylene as a powder, d. H. from the surface, e.g. B. in the fluidized bed process, too sulfochlorinate. However, this process leads to products which are not sufficiently thermally stable. the After being kept at higher temperatures for some time, products show strong discoloration and This releases considerable amounts of chlorine.

It has now been found that novel and technically valuable sulfochlorination products can be obtained from after the polymerization isolated low-pressure polyethylene can be prepared by having a solution or a initial suspension of low density polyethylene with a softening point of at least about 130 ° C, a crystallinity of at least about 80% and a content of less than three methyl groups per 100 methylene groups, optionally after prior chlorination, in relation to the reactants inert solvents, preferably halogenated hydrocarbons, subject to sulfochlorination, with the exception of a method that works first at elevated pressure and then at normal pressure. As a solvent are mentioned: z. B. halogenated hydrocarbons, such as carbon tetrachloride, chloroform, methylene chloride, Trichlorethylene, tetrachloroethane, dichlorobenzene, di-process for sulfochlorination

of low pressure polymers

of ethylene

Applicant:

Farbwerke Hoechst Aktiengesellschaft

formerly Master Lucius & Brüning,

Frankfurt / M., Brüningstr. 45

Dr. Ludwig Orthner, Frankfurt / M.-South,

and Dr. Horst Herzberg, Frankfurt / M.-Höchst,

have been named as inventors

fluorobenzenes tetrafluorodichloroethane. By sulfochlorination or chlorosulfochlorination of low-pressure polyethylene in solution results in sulfochlorination products, which differ from the products of surface sulfochlorination in a characteristic way and the sulfochlorination products of the corresponding high-pressure polyethylene due to their different structure are superior. Among other things, they have better processing properties.

If such solvents with a high boiling point, such as tetrachloroethane, dichlorobenzene, are used as the solvent medium, the polymer can be dissolved without pressure at temperatures above 100 ° C., preferably 110 ° C., and then treated with gaseous chlorine and a certain degree of anchlorination can be achieved; however, the request for protection does not extend to pure chlorination. As soon as a certain percentage of chlorine is introduced into the polymer, the temperature can be lowered and, at lower temperatures, e.g. B. at 20 to 50 ° C, sulfochlorinated in order to obtain good utilization of the gaseous reactants. If carbon tetrachloride is used as the solvent, the reaction must be carried out at temperatures increased by pressure in order to achieve a solution of the polymer. Here, too, the entire amount of chlorine and sulfur dioxide in the pressure vessel can advantageously be introduced at temperatures above 100 ° C., as a result of which extremely short reaction times can be achieved with almost quantitative utilization of chlorine. Under certain circumstances - without removing the reaction pressure - the temperature can be lowered after some time, thereby _{facilitating the introduction of SO 2} Cl groups into the polymer. In this case, however, it is desirable not to work at excessively high pressures so that the gaseous reactants do not liquefy.

909-640/440

Claims (1)

If chloroform is used as the solvent, it is advantageous to remove everything in the reaction space before the start of the chlorination to expel existing oxygen by inert gas. Instead of the gas mixture of chlorine and Sulfur dioxide, which can be in any proportion to one another, is also possible, sulfuryl chloride and to use chlorine, thionyl chloride and chlorine and the like for introducing the salt-forming group. The sulfochlorination process described, which can also be carried out continuously, can be used for low-pressure polyethylene of various molecular weights can be used. The sulfochlorination measures outlined can be catalyzed by using the usual reaction accelerators that enable or accelerate the introduction of halogen and sulfur dioxide into hydrocarbon chains, such as, for. B. heavy metal halides, per-oxygen compounds, organic azo or hydrazo compounds. You can also use high-energy light. The processing of the sulf ο chlorinated polyethylene solutions is carried out under certain circumstances after stabilization with the usual hydrochloric acid-binding agents, such as phenoxypropene oxide, organic tin stabilizers, by precipitation with methanol or driving out the solvent, possibly after emulsification with water using emulsifiers, including those that z . Example, be cleavable by p _H alteration, by means of superheated steam, by spraying the sulfochlorinated Polyäthylenlösungen or emulsions in hot inert gas atmosphere or in the presence of steam, under circumstances in vacuo. The sulfochlorinated Niederdruckpolyäthylene represent elastomeric or guttaperchaähnliche or solids that drafting machine in the usual manner to the plastic \ ^r, such as rolling, calendering, extrusion, can be processed. They have excellent film-forming properties and are therefore suitable for the production of foils, as intermediate layers for bonds, together with the usual fillers as floor coverings; they are also excellent plasticizers for other plastics. Particularly valuable and technically versatile plastics are obtained when the sulfochlorinated low pressure polyethylene together with polyvalent compounds such as metal oxides, e.g. B. Magnesium oxide, zinc oxide, lead oxide, or halides, e.g. B. calcium chloride, barium chloride, zinc chloride, aluminum chloride, Antimony chloride, or polyamines, e.g. B. ethylenediamine, propylenediamine, triethylenetetramine, Hexamethylenetetramine, according to the usual methods of peroxide, heavy metal, sulfur or amine hardening vulcanized together with suitable pigments. Vulcanized sulfochlorinated low-pressure polyethylenes are distinguished from vulcanized sulfochlorinated High pressure polyethylenes, ζ. Β. a sulfochlorinated one prepared according to the process of U.S. Pat. No. 2,640,048 High-pressure polyethylene is characterized by better tear strength. For example, one obtains from a Rolling mix, which consists of the following components: 200 g sulfochlorinated polyethylene, 6 g stearic acid,
80 g PbO,
4 g mercaptobenzothiazole, and on the one hand a sulfochlorinated high pressure polyethylene and on the other hand a sulfochlorinated low pressure polyethylene was used, after a vulcanization of 30 minutes at 160 ° C. Vulcanizates with the following Characteristics: ς Tear strength, kg / cm ² Sulfochlorinated Sulfochlorinated D. Rebound resilience ... High pressure Low pressure polyethylene polyethylene with 1.5% S. with 1.1 ° / ₀ p and 28.5% and 29.8% Total Cl Total Cl IO 66 123 19% 20% example 1 150 parts by weight of low-pressure polyethylene (η specIc = 1.12, measured at 130 ° C. as a 0.5% solution in tetrahydronaphthalene) are dissolved in 2000 parts by weight of tetrachloroethane at 110 ° C. and gassed with 4 parts by weight of chlorine per minute under UV radiation. After 90 minutes the reaction temperature is lowered to 50 ° C and the ratio of sulfur dioxide and chlorine is reduced 1: 2 initiated. The degree of sulfochlorination is monitored by ongoing sampling. Once the reaction product has a sulfur content of 1.6% and a Shows chlorine content of 25.5%, the reaction is terminated and after degassing with nitrogen the Rubber-elastic product isolated by precipitation and kneading with methanol. Example 2 In a leaded stirred autoclave, which is provided with a window through which UV light is radiated into the reaction chamber, 100 parts by weight of chlorine with 10 parts by weight are added to a suspension of 100 parts by weight of low-pressure polyethylene (η specjc = 1.17) in 3000 parts by weight of carbon tetrachloride Injected sulfur dioxide. It is then heated to 110 ° C., held at that temperature for 30 minutes, then slowly cooled to 40 ° C. and relaxed. After degassing with nitrogen, 1000 parts by weight of chloroform are added to the slightly lumpy reaction product, which dissolves it, then freed from solvents by passing in steam and rolled dry at 80.degree. The gutta-percha-like product has a Cl content of 44% and a sulfur content of 3.9%. Pat ϊ ·: ν τ α χ s ρ ρ. υ c η: Process for the sulfochlorination of low-pressure polyethylene isolated after the polymerization, characterized in that there is a solution or an initial suspension of low-pressure polyethylene having a softening point of at least about 130 ° C, a crystallinity of at least about 80% and a content of less than three methyl groups per 100 methylene groups, optionally after prior chlorination, in solvents which are indifferent to the reactants, preferably halogenated hydrocarbons subjected to sulfo-chlorination, a process described in two pressure stages works, is excluded. References considered: U.S. Patent No. 2,640,048; interpreted documents of Belgian patent 545 364.