Process for the processing of vehicle tires

Abstract

The invention relates to a method for processing vehicle tires which are formed at least from elastomer material with embedded reinforcements, comprising the steps of providing the vehicle tires to be processed, separating the reinforcements from the elastomer material by mechanically crushing the vehicle tires to particle sizes of 1 to 3 mm and subsequently classifying them using gravity and / or centrifugal force separation to separate them into separate fractions of the elastomer material and the reinforcements.

Description

The invention relates to a method for processing vehicle tires which are formed at least from elastomer material with embedded reinforcing members.Vehicle tires in the sense of the invention are, for example, bicycle tires, car tires and generally tires for single- and multi-track vehicles, both in the form of pneumatic vehicle tires and solid rubber tires including further components, such as hoses and, for example, metallic accessories, such as valves, which are also referred to below as accessories.In a large number of such vehicle tires, their function is achieved only by a material composite made of polymers, in particular elastomer material and embedded reinforcing members, which comprise, for example, yarns made of textile fibers, such as polyamide (nylon), polyester, cotton, rayon, or else yarns made of liquid crystal polymers or synthetic liquid crystal polymers, such as aramid fibers (Kevlar®) or fibers made of aromatic polyesters, such as Vectran®. If such reinforcing elements are embedded in the elastomer material, separation into recycling materials of the same type during the processing of the vehicle tires has not been possible up to now. This creates conflicts in goals, for example when developing readily recyclable composite materials, for example puncture protection inserts for bicycle tires.In addition, the production of high-quality products from recycled materials requires high demands on the recycled materials to be used, in particular their purity of grade. Only by high purity of the species is it possible to separate, for example, different material properties of hydrophobic or hydrophilic materials, since this would otherwise result in avoidable weak spots. Due to these high requirements for the purity of the type of recycled materials from the processing of vehicle tires of the type mentioned at the beginning, the potential and also the demand for elastomer-reinforcing composite materials is reduced. However, since regularities are increasingly to be expected in the future in the direction of establishing circulatory business, the need for action increases in order to work up established elastomer-reinforcing composite materials, such as puncture protection inserts and the like, and to take into account the workability already in the design and development phase.It is an object of the invention to propose a simple method for processing vehicle tires that can be operated with little effort and that enables a reliable separation of the provided vehicle tires into a fraction of the elastomer material and a further fraction of the reinforcing members without subjecting the elastomers or reinforcing members present in the fractions to an undesirably strong degradation.To achieve the object set, according to the invention, a method according to the features of claim 1 is proposed.Advantageous embodiments and developments of the invention are the subject matter of the dependent claims.The proposal according to the invention provides that the vehicle tires to be treated, including the existing accessories, are provided and, in a first step, are brought by mechanical precomminuting to a size which is easy to handle subsequently and which is guided by the existing machine specification. According to the invention, a separation of the elastomer materials from the embedded reinforcing members is subsequently effected, so that the reinforcing members and the elastomer material separated in this way can subsequently be subjected to a classification step in which the reinforcing members, on the one hand, and the elastomer material, on the other hand, are divided into separate fractions of high purity of grade. These separated fractions can then be separated further in subsequent further processing steps or can be fed directly to a recycling process.The essential advantage of the method according to the invention is that the elastomer material and the reinforcing members are separated from one another without excessively degrading the specific material properties thereof, so that the fractions obtained can be reused without any problem.According to one proposal of the invention, the fraction of the elastomer material is separated from the embedded reinforcing members by a fine comminution following the precomminution, in which the material originating from the precomminution is comminuted to particle sizes of 1 to 3 mm, the reinforcing members separating from the elastomer material. These can then be divided into separate fractions for separate further processing using the separation of heavy and / or centrifugal force.According to an alternative embodiment of the invention, in the case of a suitable elastomer material, e.g. based on thermoplastic elastomers, the separation of the reinforcing elements from the elastomer material can be effected by the elastomer material being dissolved in a solvent and / or melted by supplying heat after the pre-comminution, whereby thermoplastic materials contained in the elastomer material, in particular, which are used as rubber substitutes, for example inner layers or carcass elastics, can be separated and fed to a reuse in the same type. A depolymerization of polymers contained in the elastomer material is also suitable in order to effect a separation.If metal parts are also contained in the vehicle tire, for example wire inserts or also valves or valve seats, these can, according to a further proposal of the invention, be separated in a magnetic separator before or even after the strength members have been separated off, in order to feed them to a recycling of the same type. However, it is a prerequisite that these metal parts are produced from magnetizable metal materials.Non-magnetizable metallic materials are also separated out in the heavy and / or centrifugal separation carried out, since they usually have a large density difference from the elastomer material and can therefore easily be separated off. For example, typical elastomeric materials have a density in the range of 0.8 g / cm^3 to 1.2 g / cm^3, and metallic materials have a density greater than 3.5 g / cm^3.The mechanical pre- and / or fine comminution of the vehicle tires provided according to the invention can be effected according to a proposal of the invention by planing, shredding and / or wave shredding, so that low-cost standard processes can be used.The elastomer material contained in the vehicle tires can contain both synthetic and natural rubber and / or thermoplastic elastomers and polyolefin, such as polyethylene, and can be comminuted to granules having a particle size of between 1 and 3 mm.The reinforcing elements contained in the vehicle tires comprise fibrous yarns based on polyamide, polyester, cotton, rayon or else yarns made of liquid crystal polymers and / or aramids and / or aromatic polyesters. Aramid yarns are often used under the designation Kevlar® and aromatic polyester yarns are used under the designation Vectran® in vehicle tires.The classification provided according to the invention of the comminuted vehicle tires separated into elastomer material and reinforcing elements can be carried out according to a proposal of the invention in a air separator and / or by floating in a liquid, wherein combinations of the classification methods and / or the above-mentioned further methods for separating the elastomer material can also be used.With the invention described above, polymers or elastomer materials and embedded reinforcing members of vehicle tires and their optionally present further components are reliably separated into fractions of the same type without excessively degrading the separated materials, so that they are suitable for supply into technical processes of a circulatory business and enable sustained production and waste amounts which are produced are reduced.The method is advantageous for the preparation of pneumatic vehicle tires.The method has proven to be particularly advantageous for the processing of bicycle tires and / or motorcycle tires, preferably bicycle tires.

Claims

A method for processing vehicle tires formed at least from elastomeric material with embedded reinforcing members, comprising the steps of providing the vehicle tires to be processed, mechanically precomminuting the vehicle tires and separating the reinforcing members from the elastomeric material, and then classifying them into separate fractions of the elastomeric material and the reinforcing members.Method according to Claim 1, characterized in that the detachment of the reinforcing elements from the elastomer material is effected by fine comminution to particle sizes of 1 to 3 mm following the precomminuting, and the classification thereof is effected using separation by gravity and / or centrifugal force.Method according to Claim 1, characterized in that the bonding elements are separated from the elastomer material by dissolution of the elastomer material in a solvent following the precomminuting and / or melting and / or depolymerization.Method according to one of Claims 1 to 3, characterized in that the vehicle tyres contain metal parts which are separated in a magnetic separator before or after the strength members have been separated off.Method according to one of Claims 1 to 4, characterized in that the mechanical precomminuted and / or fine comminution is effected by planing, shredding and / or wave shredding.Method according to any one of claims 1 to 5, characterised in that the elastomer material comprises synthetic and / or natural rubber and / or thermoplastic elastomers.Method according to any one of claims 1 to 6, characterized in that the reinforcing elements comprise fibrous yarns based on polyamide, polyester, cotton or rayon and / or yarns made of liquid crystal polymers and / or aramids and / or aromatic polyesters.Method according to one of Claims 1 to 7, characterized in that the classification is carried out in a air separator, by floating in a liquid and / or by filtration.Method according to one of Claims 1 to 8, characterized in that the vehicle tyre is a pneumatic vehicle tyre.Method according to claim 9, characterised in that the pneumatic vehicle tyre is a bicycle tyre and / or a motorcycle tyre, preferably a bicycle tyre.