CH687374A5 - Process for recycling Folienabfaellen, recycled material and its use. - Google Patents

Description

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description

The invention relates to a method for recycling film waste made of thermoplastic plastics of the formula -CRH-CH2- provided with pressure-sensitive adhesives, where R = H, -CH3 or phenyl, in particular waste of self-adhesive films free of protective paper. Such film material is in particular in the form of waste material from the production of self-adhesive labels. The waste material can be printed in one or more colors and optionally also be provided with a sealing cover layer.

The film material of self-adhesive films of good quality usually consists of polyethylene, in particular LD polyethylene. It can also consist of polypropylene or polystyrene. The self-adhesive films are usually supplied by the manufacturer in roll form, the adhesive side of the self-adhesive film being covered with a removable protective paper, for example silicone paper. The label manufacturer rejects the adhesive-repellent side of the film and cuts it to form the label. After the protective paper has been removed and the labels removed from the film web, there is then a lattice waste made of self-adhesive film which has been freed from the protective paper and is wound up on a roll core. Such wraps of film waste can also consist at least in part of full-area film material, for example defective material, e.g. due to misprinting or other errors in one of the layers must be discarded.

Although polyolefins and polystyrene, unlike other plastics, are considered “environmentally friendly”, there are problems with their removal. Burning is ecologically and economically undesirable. Storage in landfills means postponing disposal.

Attempts to reprocess the self-adhesive film material have shown considerable problems. Detaching the adhesive coating in organic solvents is expensive and is ruled out for ecological reasons. Because of the high proportion of adhesive, such film wraps are very difficult to shred, the cutting tools being stuck to film remnants and losing their functionality. Melting the entire film roll is complicated and leads to unusable melts.

The invention is therefore based on the object of developing a method for recycling polyolefins provided with elastic adhesives and of creating new uses for the recycling material.

This object is achieved by a process for recycling film waste provided with pressure-sensitive adhesives, in particular waste from self-adhesive films free of protective paper, which is characterized in that the adhesive-containing waste of the film material is comminuted in the presence of essentially non-adhesive waste, which essentially consists of consist of the same plastic or have the same properties,

and that the adhesive and the non-adhesive plastic parts are mixed during shredding. The invention relates in particular to a method for recycling lattice waste that is produced in the production of self-adhesive labels. The invention further relates to reusable recycling material obtained using the plastics provided with pressure sensitive adhesive material, and to products made therefrom.

The waste of self-adhesive films intended for recycling can be used in particular in the form of rolls or coils. The roll core can advantageously consist essentially of the same or a similar plastic as the film waste wound thereon, so that the roll core can also be comminuted and processed during the processing of the wound material. This procedure eliminates the work steps for detaching the wound film material from the roll core and the separate disposal of the roll core. It is possible to use roll cores made from recycled material, which is preferably obtained using the recycling process described here. The method according to the invention thus allows a polyolefin or polystyrene to be prepared and reused several times in the recycling process.

Another advantage of the joint processing of film material and roll core results from the fact that the material used for the roll core contains no or only a small proportion of adhesive substances. When crushing adhesive polymer material, there is normally blockage and obstruction in the course of the work process due to adhesive material on the cutting tools, which make it necessary to stop the machines and clean the cutting tools and sieving units. This is avoided according to the invention by the adhesive, i.e. A sufficient amount of non-adhesive polymer material is mixed with the permanently adhesive adhesive-provided polymer material during comminution, so that sticking of adhesive material to the comminution tools is prevented and, in particular, the tools are freed of any adhesive material that may be adhering. This reduces the forced downtimes of the shredders, which has an advantageous effect on the effectiveness of the recycling system. At least 1 part by weight, preferably 3 to 10 parts by weight, of essentially non-adhesive polymer can be mixed in per part by weight of self-adhesive film. When film rolls and their roll cores are processed together, the roll cores can make up a proportion of the non-adhesive material.

Further polymer waste of the same or similar polymer can thus be mixed into the adhesive film material to be processed and can be recovered together by the recycling method of the invention. Such additional material can be in particular in the form of packaging material such as containers or wrapping films, for example from industry and trade, film material from the field of agriculture such as agricultural films,

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or molded parts such as pipes, cable sheathing or components. A similar polymer material is one that has similar or compatible properties and does not impair the desired properties of the recycling product. This also includes copolymers of the polymers mentioned.

The polymer materials from wastes of various origins are in a grinding plant, crushed into particles a few millimeters in diameter. In the course of the shredding process, materials from different origins are mixed intensively, so that particles of adhesive and non-sticky polymer can then be removed as a uniform mixture from the shredding system. The composition of this recycling raw material, in particular the proportion of adhesive polymers to non-adhesive and the composition of the non-adhesive components, determines the properties and thus the possible uses of the recycling material. The content of adhesive material in the recycling raw material can be regulated by appropriate selection and metering of the polymer material fed to the comminution system and the separate feed from a neutral mixing silo. The method according to the invention thus allows sticky polymer wastes to be converted into usable products.

To ensure that the recycling process runs smoothly and that the product is perfect, it is important that the various polymer materials, in particular polyethylene (PE), polypropylene (PP) and polystyrene, are collected and processed separately. All of the polymer material used for recycling is preferably free of paper residues. Recycling material made of thermoplastic polymer according to the present invention, in particular from the processing of polyethylene or polypropylene, therefore consists essentially of only one polymer and contains a proportion of polymer derived from self-adhesive films and its adhesive material. The proportion of self-adhesive films preferably comes at least predominantly from waste generated in the manufacture of labels, in particular lattice waste. The polymer material for self-adhesive films is usually made of LD (low density) polyethylene.

The polyolefin recycling material according to the invention can essentially consist of LD polyethylene. A proportion of HD (high density) polyethylene does not have a disruptive effect within certain limits depending on the application. The polyolefin recycling material made of LD polyethylene can contain HD polyethylene, in particular in an amount of 0.5-10% by weight, in particular 1-5% by weight, in particular if it is desired to have a plasticizing effect on the To compensate for glue.

In addition to the polymer film, a self-adhesive film, in particular for labels, is generally composed of adhesive material, colorants of the print and, if appropriate, a lacquer seal on the surface. The adhesive material can consist, for example, of an acrylate adhesive or a rubber adhesive. Hot melt pressure sensitive adhesives are also suitable. As coloring substances e.g. Acrylic paints, possibly UV-cured, should be available. A lacquer seal can e.g. be applied in the form of a UV-cured polyurethane. Surprisingly, it was found that these substances do not have a negative effect on the recycling product. These components are usually only present in small quantities in the recycling product and behave in a comparable way to fillers. The adhesive originating from the self-adhesive film can in particular be present in a proportion of approximately 0.5-5% by weight, in particular 1-3% by weight. Volatile adhesives and other components can be largely removed from the polymer melt by degassing, in particular in a vacuum.

Advantageously, the polyolefin particles comminuted in a cutting system are washed before further processing, e.g. to remove any residues of content products that may be present by adding packaging material. If necessary, polymers which are not the same or of the same type can also be separated off in a separation plant. Washing is preferably carried out with water at ambient temperature, followed by e.g. in a hot air stream, is dried. The cleaned dry polymer particles are for an optional intermediate storage, e.g. in a silo or appropriate container.

The mixture of polymer particles can be melted, especially in an extruder such as e.g. a single screw extruder, and optionally filtered. The extrudate can then be shaped in a suitable manner, preferably pelletized. As mentioned, the polymer is preferably carefully degassed during and / or after melting, volatile constituents being removed. Commercial additives and additives and optionally dyes can advantageously be mixed into the polyolefin mixture before and / or after melting.

The recycling polymer present in the form of particles, in particular in the form of granules, after the melting process can now be further processed like corresponding virgin polymer material. The granulated recycling polymer is characterized by good miscibility with new granulated material. Therefore, depending on the desired properties and intended use of the product to be manufactured, mixtures of recycled material and virgin material can be used. Products made from recycled polymer have good mechanical properties so that they are competitive with corresponding products made from virgin material. The advantageous properties of the recycling polymer obtained by the process according to the invention make it possible to produce products made entirely from recycling material.

The polymer granules are preferably melted with the aid of an extruder and into the ge5

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desired shape extruded. In particular, injection molding processes, extrusion or film extrusion processes and co-extrusion coating processes can be used. In this way it is possible to manufacture products from polymer recycling material, which in particular in the form of molded parts such as injection molded parts or continuous cast parts e.g. for use as components for vehicles. The recyclate can be produced in the form of tubes or channels with particular advantage. As an endlessly manufactured pipe, the polymer material can then serve as a receiving pipe for lines and cables. Such a recycled polymer tube can be cut into correspondingly long pieces e.g. can also be used as a core for a film wrap. In this way, the recycled polymer material can be recycled when recycling the film material, e.g. litter waste from label production can be recovered.

Preferably the recovered polymer is in the form of composite films, composite film tubes or other coextruded film products, e.g. as packaging and cover films, rubbish bags, agricultural films etc. In a further preferred form, the recycling polymer is in the form of a cable sheathing, e.g. for cables in electrical engineering.

The recycling material can be used in connection with virgin material of the same olefin for the production of composite bodies, in particular with common thermoplastic deformation. The polymer recyclate can be used to produce a composite material which has a core of recycling material and at least one layer, in particular a surface layer, e.g. has virgin material.

Further features of the invention result from the following description of preferred embodiments in connection with the subclaims. Here, the individual features can be implemented individually or in combination with one another in the individual embodiments.

example 1

Polyethylene (LD-PE) waste intended for recycling consists of 20% by weight of self-adhesive films and 80% by weight of other non-adhesive PE waste. They are placed in a shredding plant, e.g. crushed in a mill. The adhesive film waste is applied together with non-adhesive material to prevent the cutting tools and sieve units from sticking together due to excessive amounts of adhesive material. The polyethylene is crushed to a particle size of approximately 12 mm in diameter, the polymer particles originating from different starting products being mixed. Before further processing, the ground particles are washed if necessary to remove adhering contaminants as well as product residues or foreign material from the previous use of the PE material. For this, the material is e.g. in a so-called floating sinking

drive or hydrocyclone process with water at room temperature. It is then dried in a hot air stream. The dry particles are fed into an extruder and melted, if appropriate after admixing further particle material from other grinding batches. For example, a single screw extruder with an L: D ratio of 1:37 can be used for this purpose. During the extrusion process, the polyethylene matrix is degassed in a degassing zone by means of vacuum, so that at least some of the adhesives, paint and other volatile accompanying substances are removed. The polymer is fed through a filter unit to a hot granulating device and then cooled. This recycled granulate can be processed like new material granulate.

Example 2

PE waste consisting of lattice waste from self-adhesive films and PE film waste from industry and trade are processed together into granules according to Example 1. This is fed into an extruder without the addition of further polymer material and extruded in the form of an endless tube. This pipe is made entirely from recycled materials. It can be used for pipelines or for the production of film winding cores.

To achieve virgin material values on the pipe surface, a coextrusion process can be used to produce a composite material. For this purpose, a core is formed from recycling material, which is coextruded with at least one surface layer of virgin material.

Example 3

Self-adhesive film waste made of LD polyethylene is in the form of wraps of misprinted label adhesive film that are up to approx. 1 m in diameter. The winding cores are also made of LD polyethylene, with the PE winding core accounting for approx. 1% of the weight of the entire winding. Containers of cleaning and cosmetic products as well as used buckets and other related molded parts, which were collected separately and separated from other types of polymer, are mixed in a proportion of 70% by weight as adhesive-free PE waste. The film windings are shredded together with the PE winding cores, the PE containers being fed in and shredded at the same time as described in Example 1. Foil adhesive labels on the containers make up about 1 to 1.5% by weight of the PE waste, which is free of adhesive material. After leaving the cutting system, the PE particles are washed, melted and granulated as described in Example 1.

Example 4

Waste of PE self-adhesive film on PE wrapping

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Core are processed together with molded parts made of PE to granulate according to Example 3. Using the coextrusion method, the recycling material is melted by means of a melt extruder and fed to the film molding tool, at the same time virgin polymer is fed to the same molding tool by two other melt extruders in order to produce a so-called sandwich film product, i.e. two thin layers of virgin material and the middle layer of recycled material. The foil thus extruded can be used for garbage bags, cover foils and hoods, e.g. Agricultural film or pallet shrink hoods can be used.

Example 5

Polystyrene waste consisting of lattice waste from self-adhesive films and polystyrene waste from industry and trade are processed together according to Example 1 and by adding additives to granulate. This is fed to an injection molding system without the addition of further polymer material. The granulate is processed into hangers, flower pots, flower bowls and various covers for industry at cycle-dependent intervals. With regard to its mechanical and optical properties and its production costs, it corresponds in part to the articles made from virgin material.

Claims (10)

Claims 1. A process for recycling film waste made of thermoplastic plastics of the formula -CRH-CH2-, provided with pressure-sensitive adhesives, where R = H, -CH3 or phenyl, in particular waste of self-adhesive films free of protective paper, such as lattice waste arising in the manufacture of labels, characterized in that the adhesive-containing film waste is crushed in the presence of substantially non-adhesive waste, which consist essentially of the same or similar properties in plastic, and that the adhesive and the non-adhesive plastic parts are mixed together during shredding. 2. The method according to claim 1, characterized in that the waste of the films provided with pressure-sensitive adhesives are used in the form of rolls or coils wound on a core, and that the core of the roll consists essentially of the same or similar properties of plastic like the film waste wound on it, and that the roll core is also crushed and processed when the winding material is shredded. 3. The method according to claim 1 or 2, characterized in that roller cores are used, which in turn consist of recycling material, in particular from recycling material obtained by the method according to claim 1 or 2. 4. The method according to any one of claims 1-3, characterized in that the adhesive film waste is admixed with such an amount of non-adhesive material during crushing that is sufficient to prevent sticking of crushing tools and, in particular, to free the tools from any adhesive material that is adhering to them. 5. The method according to any one of claims 1-4, characterized in that at least 1 part by weight, preferably 3-10 parts by weight of essentially non-adhesive waste are mixed in per part by weight of adhesive film waste material. 6. The method according to any one of claims 1-5, characterized in that the comminuted mixture of adhesive and non-adhesive plastic waste, in particular in an extruder, is melted and homogenized and then preferably pelletized. 7. The method according to claim 6, characterized in that the plastic mixture is degassed during melting. 8. The method according to any one of claims 6 or 7, characterized in that additives and additives and optionally dyes are added to the plastic mixture before and / or after melting. 9. The method according to any one of claims 6-8, characterized in that the crushed plastic material is washed and dried before melting. 10. winding from waste self-adhesive films made of thermoplastic materials on a Wik core, in particular winding from lattice waste from the production of self-adhesive labels for carrying out the method according to any one of claims 1-9, characterized in that the winding core made of essentially the same or similar Like the film material, plastic consists in particular of a recyclate obtained using the film material. 5 10th 15 20th 25th 30th 35 40 45 50 55 60 65 5