tape

Abstract

Adhesive tape, in particular wrapping tape for wrapping cables in automobiles, with a textile carrier, and with an adhesive coating on at least one side of the carrier, wherein the textile carrier is at least partially made from a recycled plastic, and wherein the proportion of recycled fibers in the textile carrier is at least 50 wt.%, based on the basis weight of the carrier, characterized in that the recycled plastic is made from textile waste.

Description

[0001] The invention relates to an adhesive tape, in particular a wrapping tape for wrapping cables in automobiles, comprising a textile carrier and an adhesive coating on at least one side of the carrier, wherein the textile carrier is at least partially made of a recycled plastic, and wherein the proportion of recycled fibers in the textile carrier is at least 50% by weight, based on the basis weight of the textile carrier.

[0002] Plastic recyclates are increasingly being used to conserve resources and reduce the consumption of petroleum, which is normally used to produce plastics for fiber production.

[0003] In the generic prior art according to EP 4 092 092 A1, the fibers of the textile carrier material are obtained from recycled polyethylene terephthalate (PET) for this purpose. The recycled PET, in turn, results primarily from recycled PET bottles and, where appropriate, from recycled secondary products from the polyester industry, as explained in paragraph

[0069] therein. The PET bottles in question are mechanically washed and then shredded. This creates so-called "flakes," which are subsequently melted and processed into fibers.

[0004] Independently of this, the applicant's utility model DE 20 2019 100 588 U1 presents an alternative method for the resource-efficient production of such adhesive tapes, in which the textile carrier is at least partially manufactured using bio-based polymers. The bio-based polymers themselves can be produced from so-called "bioplastics," i.e., those that rely on raw materials that primarily contain starch and cellulose derived from biopolymers of sugar.

[0005] The state of the art has fundamentally proven itself in terms of the generally resource-efficient production of adhesive tapes, and in particular, cable wrapping tapes of the structure described above. However, the PET bottles used as raw materials in the generic state of the art according to EP 4 092 092 A1 are also used for other recycling purposes. Often, the bottles in question are even recycled entirely, so that as a result, a decreasing amount of suitable raw materials can be expected in the future. The invention aims to remedy this.

[0006] The invention is based on the technical problem of further developing such an adhesive tape and in particular wrapping tape for wrapping cables in automobiles in such a way that a plastic recyclate can be used in the production of the textile carrier, which completely or at least largely dispenses with PET bottles.

[0007] To solve this technical problem, a generic adhesive tape and in particular wrapping tape according to the preamble is characterized according to the invention in that the plastic recyclate is made from textile waste.

[0008] According to the invention, at least 50% by weight of the recycled fibers used in the production of the textile carrier come from textile waste. In addition, so-called virgin fibers from the respective plastic can also be used to produce the fibers used to create the textile carrier in question. Furthermore, it is conceivable that the textile carrier, in addition to the at least 50% by weight from textile waste, also uses recycled plastics from, for example, PET bottles (PET = polyethylene terephthalate) if the textile carrier is made of polyester, and in particular PET. This is usually the case because polyester or PET fibers are characterized by excellent mechanical properties, chemical stability, and a high melting point. Furthermore, most textile waste is made from such PET fibers.This makes the textile waste in question ideal for use in the production of a textile carrier in conjunction with an adhesive tape and, in particular, wrapping tape for wrapping cables in automobiles.

[0009] This also applies, in particular, given that polyester backings or PET backings in adhesive tapes generally have a high level of abrasion resistance and a low tendency towards flagging, as described in the prior art according to EP 4 092 092 A1. However, it has been found that such properties are also observed and present when the textile backing is made from at least 50% by weight, based on the basis weight of the backing, of recycled PET from textile waste. Comparable mechanical values ​​are observed for backings made from at least 50% by weight of recycled PET (from textile waste) as for textile backings made from virgin PET fibres (i.e. petroleum-based).

[0010] In fact, the textile carriers produced in this way, based on at least 50 wt.% PET recyclate from textile waste, are characterized by comparable tear strengths to those observed for textile carriers made from virgin PET fibers. This means a maximum tensile strength in the range of 30 N / cm to 40 N / cm, which also applies to PET carriers made from virgin fibers. Furthermore, the elongation at break, at 20% to 30%, is also in the same range as for a PET carrier made from virgin fibers. The same standards as in the prior art according to EP 4 092 092 A1 are used to measure the maximum tensile strength and elongation at break.

[0011] This means that, according to the invention, it has been found that, in particular, plastic recyclate, and particularly preferably PET recyclate from PET textile waste, can be used to obtain recycled fibers. These, in turn, can be advantageously used for the production of a textile carrier for an adhesive tape and, in particular, wrapping tape for wrapping cables in automobiles, because comparable mechanical values ​​are observed to those for textile carriers made from virgin PET fibers. The textile carrier can be designed in any way, for example, as a nonwoven, knitted fabric, and, in particular, woven fabric. Multilayer carriers are also conceivable in principle.

[0012] The adhesive coating, which is applied at least on one side, is generally based on an acrylic hotmelt pressure-sensitive adhesive. Of course, an adhesive made from synthetic rubber can also be used as an alternative.

[0013] There are basically two different ways to prepare the textile waste in question for the application according to the invention. In a first alternative, the invention provides that the plastic recyclate, and in particular PET recyclate, is obtained mechanically, for example, by shredding textile production waste and / or used textiles. This textile production waste and / or used textiles can be waste from textile production, but also used clothing, shoes, etc. Even seat covers from cars or railway carriages can be recycled in this context, as they are usually made of polyester fibers or PET fibers due to the necessary abrasion.

[0014] In this context, the invention generally relies on a shredder with at least one rotating drum with circumferential pins for the mechanical shredding of plastic recyclate, and in particular PET recyclate. The pins ensure that the textile waste fed in via an infeed belt is shredded. For this purpose, the drum with the circumferential pins generally interacts with an edge through which the textile waste is fed. The feeding of the textile waste to the edge and thus to the drum can be realized and implemented using an infeed belt, for example. In principle, two adjacent counter-rotating drums, each with interlocking pins, can also be used.

[0015] The recycled PET fibers obtained in this way using the shredder can then be separated into individual fractions with fibers of the same length and thickness range. For this purpose, well-known and established methods are used, such as screen separation. As a result, a fiber mixture is generally available at the output of the shredder in which at least 80% by weight, and in particular 90% by weight or more, of the recycled fibers or PET recyclate fibers have a length of approximately 55 mm to 75 mm. Their thickness can be approximately 3 dtex. Other thicknesses or finenesses from 2 to 10 dtex are also conceivable.

[0016] Such fibers with the specified lengths can easily be further processed into a textile substrate, either by using the recycled fibers or PET recyclate fibers to produce a nonwoven fabric and depositing them on a screen belt and, if necessary, compacting them. It is also possible, however, for the fiber mixture in question to be used to produce yarns. This means that, in this case of mechanical shredding of textile waste, the recycled fibers are typically in the form of staple fibers. In principle, however, these can also be further processed into continuous filaments or yarns, so that, in this way, fabrics can also be implemented and realized as textile substrates.

[0017] An alternative to the mechanical processing of textile waste involves obtaining the recycled plastic by melting textile production waste and / or used textiles. Of course, the described processes for producing the fibers, as well as the melting and resulting fiber or filament production, can also be combined.

[0018] In this context, as with other mechanical shredding processes, the plastic recyclate or textile waste is first collected before melting or mechanical shredding. Subsequently, the used textiles and / or textile production waste thus obtained, i.e., the textile waste as a whole, are always mechanically shredded, both when subsequent melting takes place and when the mechanically shredded fibers are subsequently used directly for the production of the textile substrate—without melting.

[0019] After the plastic recyclate has been mechanically shredded, usually in the shredder described above, impurities are removed. For this purpose, the mechanically shredded fibers are passed through a filter device, which helps to retain impurities from textile waste, foreign materials, etc., preventing them from being passed on for further processing.

[0020] The resulting shredded plastic recyclate, or in the example of the shredder, the fibers, is then melted. However, it is also possible to use other mechanical shredding methods instead of the shredder, for example, shredding the textile waste in a shredding machine.

[0021] Either way, within the second basic procedure, the shredded textile waste or the shredded plastic recyclate obtained in this way is melted down. This can be done in such a way that so-called "flakes" of the plastic recyclate or PET recyclate are available during or after shredding the textile waste, which are then melted down. It goes without saying that, if necessary, additional filtering devices can be installed upstream to remove not only inorganic contaminants, but also organic contaminants such as other plastics. In any case, the shredded plastic recyclate is then fed into a so-called compounder, i.e., a device in which the shredded plastic recyclate is mixed with additives.The compounder in question can in principle also be combined with a subsequently used extruder, in particular a twin-screw extruder.

[0022] In fact, the invention works by adding a so-called chain extender to the melt or shredded plastic recyclate to ensure subsequent processing by extrusion. The chain extender in question is advantageously carbonylbiscaprolactam (CBC), which is advantageously added in a grammage of 0.2 wt.% to 2 wt.%, based on 100 wt.% of the plastic recyclate. In addition, an additive with a low melting point is usually also used to ensure the overall extrusion capability of the melt. This additive in question is a copolyester, which is added in a grammage of 2 wt.% to 10 wt.%, based on 100 wt.% of the plastic recyclate. In principle, this copolyester is also unnecessary.

[0023] In addition to these one or both additives, it is of course also conceivable to add a dye to the shredded flakes of the recycled plastic or PET. The invention is based on the realization that textile waste can be colored in different ways, so a color mixture is to be expected during the subsequent production of the textile substrate. However, if carbon black or graphite is added to the mixing process, the desired color "black" can be achieved just as well as any other conceivable color of the textile substrate.

[0024] The melt is then produced either in a compounder or in a twin-screw extruder at a temperature of approximately 230°C to 270°C. As a result, the extruder in question, and especially the twin-screw extruder, produces filaments on the output side, which can subsequently be processed into the textile substrate. This also includes the possibility of shredding the filaments into staple fibers.

[0025] Surprisingly, comparable mechanical properties of an adhesive tape, and in particular of a wrapping tape, made from the textile carrier of the adhesive coating in question were observed, as are known for virgin fibers made from petroleum-based PET. This applies not only to the previously mentioned maximum tensile strength in the longitudinal direction in the range of 30 N / cm to 40 N / cm and also the observed elongation at break in the longitudinal direction in the range of 20% to 30%. In general, comparable abrasion resistance was also observed, which is particularly relevant for the intended application of wrapping cables. In fact, in this context, a nonwoven carrier with a basis weight of approximately 70 g / m 2consisting of PET fibers with a length of 60 mm to 65 mm and a thickness of 3 dtex and taking into account a PET sewing thread with a strength of 50 dtex (9 threads / cm fleece width), an abrasion resistance on a mandrel with a diameter of 5 mm in accordance with standard LV 312-1 "Protection systems for power sets in motor vehicles, adhesive tapes; test guideline" (10 / 2009) of regularly 5 double strokes to 10 double strokes.

[0026] The invention is explained in more detail below with reference to a drawing which merely represents an exemplary embodiment; in the drawings: Fig. 1 a shredder machine according to the invention for mechanically shredding textile waste and Fig. 2 schematically shows the production of the textile carrier from textile waste.

[0027] In the Fig. 1 shows a shredder 1, with the aid of which textile waste can be mechanically shredded. The shredder 1 in question is also used in the context of the Fig. The basic procedure shown in Figure 2 is used on the inlet side. This requires that the textile waste to be processed is first collected and then transferred to a rotating infeed belt 2 located there.

[0028] With the help of the infeed belt 2, the textile waste is Fig. 1, specifically toward a pre-press roller 3, which is also essentially unnecessary. Furthermore, the textile waste is fed to a pair of rollers 4, 5. Roller 4 has a smooth circumference and prevents individual pieces of textile waste from falling off. The additional feed roller 5, on the other hand, can be profiled in the casing area.

[0029] The feed roller 5 is covered in the upper area with a sealing part 6 and acts on the underside against a stationary trough 7, at the upper end of which an edge 8 is provided. The textile waste is guided over the edge 8 into a drum 9, which in turn is equipped with a plurality of pins 10 on its circumference or on its casing.

[0030] As a result, the respective workpiece or a part of a textile waste made of PET in the example can be torn open with the help of the pins 10 from the textile material brought forward in the area of ​​the stationary edge 8 and is then in the form of fibers or flakes and is taken along with the pins 10.

[0031] If the flakes or fibers have a significant mass on the circumference of the drum 9, they are collected in a separation chamber 11 on the underside of the drum 9 and can then be fed again on the circumference of the infeed belt 2. This is not shown in detail.

[0032] The shredded material carried by the pins 10 of the drum 9 also enters a channel 12 that can be identified. This causes the shredded material to be thrown into a receiving chamber 13, where it can then be collected and carried along on the periphery of a screen drum 14 that can be identified there. The screen drum 14 is equipped with a discharge roller 15 and an adjoining conveyor 16, with the aid of which the plastic recyclate fibers thus obtained, or recycled fibers made predominantly of PET, can subsequently be further processed. For this purpose, the conveyor 16 may be followed by a classification unit (not shown in detail), in which the fibers are separated according to a uniform length and thickness range.

[0033] For example, a fiber blend of recycled fibers is observed here, in which at least 80%, and in particular 90% or more, of the recycled fibers have a length of approximately 55 mm to 75 mm. The fiber fineness may be between 2 dtex and 10 dtex. This fiber blend can then be further processed, for example, into a stitchbonded nonwoven backing by depositing the fiber blend on a screen belt, compacting it, and then finishing it with the sewing threads. This is, of course, only an example and is by no means mandatory.

[0034] In the context of the variant according to the Fig. 2, the plastic recyclate is obtained by melting the textile waste or textile production waste and / or used textiles. In this case, the textile waste is collected again and mechanically shredded, for example, in the shredder 1. As an alternative to the shredder 1, one or more shredding machines can also be used at this point to prepare the textile waste for melting.

[0035] Following the shredder machine 1, which can be designed as an example and as shown in the Fig.As shown in Figure 1, the mechanically shredded textile waste, and in particular PET waste, is fed to a washing and / or filtering device 17. Here, the shredded textile waste is washed and freed of impurities. A filtering process can also be provided, for example, to remove overly large components of the plastic recyclate.

[0036] Following the washing and / or filtering device 17, the thus processed plastic recyclate is fed to a mixing chamber or compounder 18, in which the plastic recyclate is treated with additives 19. The additives 19 can be the CBC already mentioned above, the copolyester, and / or a color. In principle, however, the mixing chamber 18 can also be integrated into or combined with a subsequent extruder 20. For this purpose, the extruder 20 can be a twin-screw extruder 20. At the output side of the extruder 20, for example, continuous filaments from the molten plastic recyclate are then available, using the textile waste and, in particular, the PET recyclate.The continuous filaments can then be further processed into staple fibers or yarn, which can then be woven into a fabric as a textile carrier for the adhesive tape. Adhesive tape produced in this way is used primarily as wrapping tape for wrapping cables in automobiles. For this purpose, the wrapping tape in question is wrapped either spirally or longitudinally around the cables to be gathered together and bonded either to the cables or to itself, or to both. This is generally known. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 4 092 092 A1 [0003, 0005, 0009, 0010] DE 20 2019 100 588 U1

[0004]

Claims

[1] Adhesive tape, in particular wrapping tape for wrapping cables in automobiles, with a textile carrier, and with an adhesive coating on at least one side of the carrier, wherein the textile carrier is at least partially made of a recycled plastic, and wherein the proportion of recycled fibers in the textile carrier is at least 50% by weight, based on the basis weight of the carrier, characterized by that the plastic recyclate is made from textile waste. [2] Adhesive tape according to claim 1, characterized by that the plastic recyclate is obtained mechanically, for example by shredding from textile production waste and / or used textiles. [3] Adhesive tape according to claim 2, characterized by that a shredding machine (1) is provided with at least one rotating drum (9) with circumferential pins (10), which shreds the textile waste fed in via an infeed belt (2). [4] Adhesive tape according to claim 1, characterized bythat the drum (9) interacts with an edge (8) over which the textile waste is fed. [5] Adhesive tape according to one of claims 1 to 4, characterized by that the recycled fibers obtained are separated into individual fractions with fibers of the same length and thickness range. [6] Adhesive tape according to claim 5, characterized by that in the fiber mixture at least 80%, preferably 90% and more of the recycled fibers have a length of approximately 55 mm to 75 mm and preferably a thickness of, for example, 3 dtex. [7] Adhesive tape according to one of claims 1 to 6, characterized by that the plastic recyclate is obtained by melting textile production waste and / or old textiles. [8] Adhesive tape according to one of claims 1 to 7, characterized bythat the plastic recyclate is collected before melting and is first and preferably mechanically shredded in the shredder machine (1) and then any impurities are removed in a washing / filtering device (17). [9] Adhesive tape according to one of claims 1 to 8, characterized by that at least one chain extender is added to the shredded plastic recyclate. [10] Adhesive tape according to one of claims 1 to 9, characterized by that an additive with a low melting point is added to the shredded plastic recyclate to ensure the extrusion capability of the melt. [11] Adhesive tape according to one of claims 1 to 10, characterized by that the melt is produced in a compounder (18) at about 230°C to 270°C. [12] Adhesive tape according to claim 11, characterized by that the compounder (18) is a component of an extruder (20) and in particular a twin-screw extruder (20). [13] Adhesive tape according to one of claims 1 to 12, characterized by that the chain extender is present in a grammage of 0.5 wt.% to 2 wt.%, based on the weight of the shredded plastic recyclate. [14] Adhesive tape according to one of claims 1 to 13, characterized by that the additive with a low melting point is present in a grammage of 2 wt.% to 10 wt.%, based on the weight of the shredded plastic recyclate. [15] Adhesive tape according to one of claims 1 to 14, characterized by that the textile carrier or the adhesive tape has a maximum tensile strength of 30 N / cm to 40 N / cm and an elongation at break preferably of 20% to 30%.

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