CZ236098A3 - Process for preparing curing compounds from devulcanized rubber and recycled polymers - Google Patents

Abstract

No information given.

Description

Process for the preparation of vulcanizing mixtures of devulcanized rubber and recycled polymers

Technical field

The ever-expanding production of polymeric materials brings both the producers and the companies the problem of their disposal after use. Waste produced during their production is also a problem. The prevailing methods of disposal of polymer waste by landfilling with other wastes or incineration create considerable environmental problems, since polymer substances are stable against spontaneous decomposition compared to natural substances in the long term and their lifetime is extended by landfilling. Incineration develops harmful exhalation, especially PVC. For this reason, extensive research into polymer chemistry has been expanded to include tasks that would solve the problem of plastic disposal, or even better, the problem of plastic reuse. One of the most studied areas of reuse of used polymers is the economic use of used tires.

BACKGROUND OF THE INVENTION

There are already a number of proposals to use used tires, either as fuel in cement plants or for the production of soot, liquid hydrocarbons and gas. Inert atmosphere pyrolysis has also been described. However, most has so far been obtained by grinding or crushing a deeply supercooled mass (cryogenic grinding) of rubber pulp, which can be added either to asphalts or as an addition to the original material for the manufacture of less demanding rubber products. Alternatively, the rubber crumb, including rubber tire particles, is added to polymeric materials such as polyurethane, polybutadienes, polyamides and the like.

Much attention has recently been paid to the preparation of rubber modified bitumen. Mostly, the rubber pulp is added to the asphalt and the product is made into pavements for pavements and similar purposes. For the preparation of sports grounds, playgrounds, hippodromes, etc., granules of recycled rubber with polymers are used with the addition of vaseline or glycerol, bitumen emulsion, sand, acrylic, polyurethanes, latex, etc. and oil at about 300 ° C. The literature also describes how to use rubber crumb from tires as an additive to concrete. This “rubber concrete” is used for the construction of barriers on highways, specialty crops, etc.

A mixture of hydrocarbon-based solvents using decomposition gases to heat the reactor was also used for the thermal decomposition of the vulcanized rubber. For the decomposition of rubber and other plastics wastes, the use of a high temperature silicon aluminum catalyst has also been described.

However, not all of the above procedures address the problem of reusing rubber as a vulcanizable raw material. Recently, however, information has emerged on processes which, together with higher temperatures and mechanical action with the addition of chemicals, disrupt intermolecular bridges. In this way, a recycled material approaching the properties of the butadiene-styrene copolymer starting material containing a filler addition can be obtained. However, it is not known that this process has already been used industrially somewhere.

When solving simple devulcanization, it must be taken into account that even the raw macromolecules of the raw rubber are relatively long intertwined and have a certain proportion of transverse chemical bonds between them. However, unlike vulcanized rubber, the starting raw rubber is well soluble in aromatic hydrocarbons such as benzene, toluene and the like. On the other hand, the rubber does not dissolve in any solvent, but only swells, which is used as one of the proofs of structure, respectively. degree of rubber vulcanization. Further evidence of the degree of vulcanization is the influence of heat. The devulcanised rubber is thermoplastic, softening as the temperature rises. Rubber, on the other hand, is not thermoplastic at all. The degree of devulcanization can also be inferred from the different behavior of the two materials during deformation.

The de-vulcanization of the rubber in which the sulfide crosslinks are cleaved can be carried out in the rubber suspension in the presence of a solvent in which the rubber swells (e.g. toluene) with an alkali metal such as sodium. The cleavage product is a polymer having approximately the same molecular weight as the polymer before vulcanization

Regeneration of the vulcanized rubber can also be carried out by kneading with regenerating agents containing disulfides (diphenylsulfide) and trivalent phosphorus compounds (triphenylphosphide) while heating to 150 ° C. Mixtures of zinc salts of dialkyldithiophosphimates and mercaptobenzothiazole dispersed in diols in the presence of zinc oxide and stearic acid were also used for rubber devulcanization.

The construction of a dynamic devulcanizer with direct heating by means of infrared radiation has also been described for the preparation of regenerated rubber. In addition to the physical vulcanized rubber regeneration processes including, but not limited to, thermal treatments for oil-based heating, a variety of chemical agents are used to recycle rubber, e.g. The process for devulcanizing waste rubber has also been patented by heating small pre-washed sliced rubber pieces to 110-138 ° C followed by calendering, mixing with 3% powdered natural resin and reheating to 115 ° C * 138 ° C at 3-6 kg / cm ² for 1.5 - 3 hfc |

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A mixture of polypropylene glycol with isophthaloyl chloride and polyurethane, optionally with benzoyl chloride and phenylphosphonyldichloride, was also used in the recycling of halide-containing rubber wastes. For recycling of tire powder, treatment of a mixture of ferric chloride, phenylhydrazine and thiophenol at 200 ° C for 20 hours has been described.

Enzymes from thiophilic microorganisms (Rhodococcus rhodochus, Sulfolobus acidocaldarius, Thiobacillus ferrooxidans, Thiobacillus thiooxidans) were also used to selectively cleave the transverse sulfide bonds of the vulcanized rubber surface layer.

The crosslinks between the rubber macromolecules need not only be sulfur, although in most cases this is the case. The rubber can be vulcanized, for example, by higher metal oxides, trivalent phenols such as pyirogaliol or fluorogtucine, or by the action of diisocyanates and other compounds having more than one group in the molecule capable of reacting with any part of the rubber molecule.

Sulfur vulcanization of rubber does not only result in bridges between macromolecules, but a significant amount of sulfur binds to the double bonds of the entire macromolecule's main chain and numerous side chains, creating strongly polar groups which are characterized by strong charge and hence strong attraction, especially among close macromolecules .

SUMMARY OF THE INVENTION

A solution to the above-mentioned problems related to rubber devulcanization is solved by a process for preparing vulcanizing mixtures of devulcanized rubber and recycled polymers characterized by heating the rubber crumb of used tires or other waste rubber F material in an autoclave, pressure press or extruder in the presence of lactams and / or carboxylic lactones. of acids and / or crude rosin at temperatures of 140 to 230 ° C, optionally at a temperature of 140 to 230 ° C. the presence of polyolefins and / or polyesters and / or polyamides and / or a polyurel mixture

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The polyol has a phthalting agent and / or vulcanizing and / or polyesters and / or polyamides and / or polymers and / or polyurethanes or other additives and / or standard vulcanization of the vulcanizing mixtures thus prepared. According to the invention, the ongoing devulcanization described in the examples is not only to abolish most of the transverse bonds but also to weaken the electrostatic cohesive forces. According to the process of the invention, a material having the properties of a starting rubber (or a mixture of rubber with added polymers) is obtained from the waste materials, in which virtually all additives, i.e. carbon black, sulfur, optionally also polymer additives, stabilizers, antioxidants and ev. other impurities such as oil and the like. The products obtained in the examples can be re-vulcanized, i.e., to produce rubber products of comparable properties to rubber materials made from standard vulcanization compositions.

The invention is illustrated by, but not limited to, exemplary embodiments.

DETAILED DESCRIPTION OF THE INVENTION

He did

50 parts by weight of butadiene styrene rubber from the treads of passenger car tires, particle size up to 5 mm, are treated with 15 parts by weight. parts by weight of 6-capro-4-lactam and 5 wt. parts of crude rosin (a mixture of abietic acid, pimaric acid and turpentine essential oils) in an autoclave at 180 ° C and a pressure of 5 atmospheres for 20 minutes. parts of the original vulcanizing compound for the production of passenger car tires and then vulcanizing in a standard manner at 145-165 ° C. The obtained material has comparable properties (strength, elasticity, abrasion, hardness) with products prepared from standard vulcanization mixtures.

Example 2

Per 100 wt. 20 parts by weight of rubber parts from truck tires having a particle size of up to 4 mm are treated. % butyrolactone and 5 wt. parts of rosin in an autoclave at 230 ° C and 10 atmospheres pressure for 15 minutes. The product obtained is subjected to standard vulcanization after the addition of vulcanizing agents. The product of this vulcanization is a material of comparable properties to rubber obtained from standard vulcanization mixtures.

Example 3

150 parts by weight of rubber butadiene styrene pulp (a mixture of wastes produced in the manufacture of rubber soles for footwear) is mixed with 30 parts by weight of natural essential oils containing 70% terpenic substances and 10 parts by weight of 12-laurolactam. The mixture was pressurized to 10 atmospheres at 160 ° C for 15 minutes in a heated press. The product obtained is added. The mass of parts of the vulcanizing composition for the production of shoe soles and after mixing are subjected to standard vulcanization. The obtained material has comparable properties (strength, elasticity, abrasion, hardness) with products prepared from standard vulcanizing mixtures for the production of shoe soles.

Example 4

150 parts by weight of butadiene styrene rubber powder (a mixture of wastes resulting from flooring production) are mixed with 10 parts by weight of essential oils containing 70% terpenic substances, 5 parts by weight of butyrolactone and 5 parts by weight of pyrrolidone. The mixture is treated in a heated press at 10 atmospheres at 180 ° C for 10 minutes. The product is re-vulcanized after addition of sulfur, paraffin and vulcanization accelerator, the product formed having rubber characteristics comparable to products prepared from standard vulcanization mixtures. for the production of flooring.

Example 5

500 Mass parts of rubber wanted (obtained from technical rubber for normal use) with an average particle size of 3-5 mm is mixed with 5 mass dfly raw rosin, 5 mass parts

% pyrrolidone and 25 wt. parts of 6-caprolactam. After homogenization, this mixture is extruded through a single screw extruder heated to 140 ° C. The extruded mass, after mixing with the vulcanizing agents, is subjected to standard vulcanization. The technical rubber obtained has comparable properties to a product prepared from standard vulcanizing compounds for technical rubber production.

Example 6

500 Weight parts of crushed particles (up to 5 mm in size) of butadiene styrene rubber from used passenger car tires containing, in addition to the admixtures, residual polyester cord fibers are homogenised with 50% by weight. parts by weight of 6-caprolactam and 5 wt. parts of butyrolactone. This mixture is then passed through a heated twin screw extruder at 220 ° C. The extruded mass (after passing through the extruder for 5 minutes), which does not show the presence of polyester fibers, is subjected to standard vulcanization after addition of the vulcanizing agents.

Example 7

500 Weight parts of butadiene styrene rubber, from the treads of passenger cars, of a particle size of up to 5 mm, are mixed with 100 wt. parts of waste polyamide of equal particle size, 50 wt. parts by weight of 6-caprolactam and 5 wt. parts of butyrolactone. This mixture is then passed through a heated single screw extruder at 200 ° C. The extruded mass (after passing through the extruder for 3 minutes) is subjected to standard vulcanization after addition of the curing agents.

Example8

200 wt. parts of butadiene styrene rubber of treads of passenger cars, of a particle size of up to 5 mm, 200% by weight parts of rubble (obtained from technical rubber for normal use) with an average particle size of 3-5 mm and 50 wt. parts of crushed waste polyurethane are mixed with 5 wt. parts by weight of rosin, 5 wt. parts by weight of pyrrolidone and 10 wt. parts of 6-caprolactam. After homogenization, this mixture is extruded through a single screw extruder heated to 180 ° C. The extruded mass, after mixing with the vulcanizing agents, is subjected to standard vulcanization.

Example 9

500 Weight parts of crushed particles (up to 5 mm in size) of the oil-free rubber are mixed with 5 wt. parts by weight of rosin, 5 wt. % butyrolactone and 15 wt. parts of 6-caprolactam. After homogenization, this mixture is extruded through a single screw extruder heated to 220 ° C. The extruded mass is subjected to standard vulcanization after scalding with the vulcanizing agents.

-6Example 10

K 500 wt. 25 parts by weight of granulated rubbers (obtained from technical rubber for normal use) having an average particle size of 3-5 mm are added. parts by weight of polyethylene terephthalate (PET) (equal particle size) and 50 wt. parts of polyethylene (PE) crumb. The resulting mixture is homogenized together with 5 wt. parts by weight of rosin, 5 wt. parts by weight of pyrrolidone, 5 wt. % butyrolactone and 10 wt. parts of 6-caprolactam. A single screw extruder heated to 200 ° C is then extruded. The extruded mass, after mixing with the vulcanizing agents, is subjected to standard vulcanization.

They did

500 Weight parts of rubble (obtained from technical rubber for normal use) with an average particle size of 3-5 mm are mixed with 5 wt. parts of crude rosin and 30 wt. parts of 6-caprolactam. This mixture is passed through a single screw extruder heated to 180 ° C. 10 wt. % waste pulp of polyurethane. After homogenization on a calender together with vulcanizing agents, the mass formed is subjected to standard vulcanization.

Industrial applicability

The process for the preparation of vulcanizing mixtures of devulcanized rubber and recycled polymers according to the invention is useful in processing waste rubber materials, especially used tires from cars and trucks, and other polymer waste into rubber products or mixed products of recycled polymers and rubber.

Claims (4)

Patent claims Method for preparing vulcanizing mixtures of devulcanised rubber and recycled polymers, characterized in that the rubber pulp of used tires or other waste rubber material is heated to a temperature of 140 to 230 ° C in the presence of lactams and / or lactones of organic acids and / or crude optionally further in the presence of polyolefins and / or polyesters and / or polyairtides and / or polyurethanes and subsequently mixed with vulcanizing agents and / or sictricarrizer ^- sm & f and / or polyolefins and / or polyesters and / or polyamides and / or or with polyurethanes. 2. A process according to claim 1, characterized in that the mixture is heated in an autoclave or pressure press at temperatures of from 160 to 230 [deg.] C. The process according to claim 1, characterized in that the mixture is passed through an extruder at temperatures of 140 to 220 ° C. The method of claim 1, wherein the lactams are selected from the group consisting of pyrrolidone, 6-caprolactam and 12-laurolactam.