Method for manufacturing a belt webbing, and belt webbing

Abstract

The invention relates to a method for manufacturing a belt webbing (11) for a safety device in vehicles, in which method a multifilament yarn is woven into a fabric band (12) with warp and weft threads, and the woven band (12) undergoes a thermofixation process. The multifilament yarn is made of a thermoplastic polymer that is partially or entirely produced using recycled and / or renewable raw materials. The warp threads formed from the multifilament yarn have a yarn count of 750 dtex to 2000 dtex, the warp thread density of the woven band being in a range of 50 to 125 warp threads / cm. The fabric band (12) is cut to a defined length to form the belt webbing (11).

Description

[0001] Method for producing a webbing and webbing

[0002] The invention relates to a method for producing a belt strap for a safety system in vehicles and to a belt strap which is obtainable by the method.

[0003] A safety system in vehicles with a seat belt is designed to protect a vehicle occupant from injury in various types of accidents. The seat belt restrains the vehicle occupant during sudden deceleration, allowing the occupant to participate in the vehicle's deceleration as early as possible and preventing contact with objects in the vehicle, such as the steering wheel or dashboard.

[0004] A variety of plastics are used to manufacture the belt straps. However, the plastics used to date are petroleum-based and some cause significant greenhouse gas emissions along their value chain. The CO2 released through the value chain contributes to the greenhouse effect, which is responsible for global warming. Such greenhouse gas emissions are quantified using the Product Carbon Footprint (PCF), which is determined and defined by the standards DIN EN ISO 14067 and DIN EN ISO 14064-3. Product Carbon Footprint (PCF) refers to the greenhouse gas emissions generated during the production of products, from their use to their disposal. The goal is therefore to improve the environmentally friendly use of plastics, including in the area of ​​safety-relevant components, and to reduce the PCF. The production of bio-based or recycled plastics is already known.The use of bio-based or recycled plastics in vehicle safety devices has not yet been widely adopted due to the required reliability of the components. In particular, the mechanical properties of belt straps made of bio-based or recycled plastics can be subject to undesirable changes during the manufacturing process.

[0005] The invention is therefore based on the object of avoiding the above disadvantages and providing a manufacturing process for belt straps for safety systems based on sustainable raw materials.

[0006] This object is achieved by a method for producing a belt strap for a safety system in vehicles according to claim 1 and a belt strap according to claim 9.

[0007] Advantageous embodiments of the method according to the invention are specified in the subclaims, which can optionally be combined with one another.

[0008] The invention relates to a method for producing a belt strap for a safety device in vehicles, comprising the following steps:

[0009] Weaving a multifilament yarn into a fabric tape with warp threads and weft threads, wherein at least the warp threads are formed from the multifilament yarn; optionally dyeing the fabric tape;

[0010] Thermosetting the fabric tape in a heating device; optionally calendering the fabric tape; optionally applying a friction-reducing finish to the fabric tape; and

[0011] Cutting the fabric tape into a belt strap of defined length; wherein the multifilament yarn is formed from a thermoplastic polymer that is partially or completely produced using recycled and / or renewable raw materials, and wherein at least the warp threads have a yarn count of 750 dtex to 2000 dtex, and wherein the fabric tape is formed with a warp thread density of 50 to 125 warp threads / cm.

[0012] The use of recycled or renewable raw materials for the production of thermoplastic polymers and their subsequent processing into multifilament yarns enables the sustainable production of fabric-based components for vehicle safety systems with reduced PCF. This can make a significant contribution to the climate-friendly production of these components. Furthermore, the dependence on fossil raw materials for manufacturing can be further reduced. Separating from fossil raw materials in manufacturing can also reduce energy-intensive chemical reactions, thus contributing to making the proposed process more resource-efficient, sustainable, and environmentally friendly.

[0013] The invention is based on the discovery that recycled and renewable materials are also suitable for the production of safety-relevant components in a vehicle. Given the high demands placed on belt webbing, this is not a given. The inventors have recognized that thermoplastic polymers such as polyester made from renewable or recycled materials can be integrated into the production of belt webbing using the process according to the invention without compromising the safety-relevant properties of these components.

[0014] In particular, it has been recognized that the mechanical properties of webbing are subject to significant changes during the manufacturing process. For example, a woven webbing made of bio-based or recycled polyester exhibits a tensile strength in its raw state that is comparable to, or even better than, woven webbing made of petroleum-based polyesters with the same yarn count and warp thread density. However, after heat-setting, the tensile strength of woven webbing made of recycled or bio-based yarns can decrease significantly more than that of woven webbing made from petroleum-based multifilament yarns. This poses the risk that the manufacturer's specifications for the mechanical strength of the webbing cannot be reliably met when using multifilament yarns made from sustainable raw materials.

[0015] The method according to the invention therefore provides that, for the production of webbing from bio-based or recycled raw materials, the yarn count is increased by approximately 3 to 10% compared to conventional petroleum-based multifilament yarns. Alternatively or additionally, the warp thread density can also be increased by approximately 3 to 10% compared to conventional webbing. According to the invention, at least the warp threads running longitudinally in the finished webbing should have a count of between 750 dtex and 2000 dtex, and / or the warp thread density should be in a range of 50 to 125 warp threads / cm. This ensures that the manufacturer's specifications regarding the mechanical strength of the webbing can be met not only in the raw state, but also after all processing steps.

[0016] According to one embodiment, the multifilament yarn has a nominal yarn count of 830 dtex. "Nominal value" here and below refers to the target value of the manufacturer's specification and includes standard manufacturing tolerances. Manufacturing tolerances are usually approximately ± 1.5%. In this case, the increased warp thread density of the woven tape lies in a range from 103 to 121 warp threads / cm, preferably 112 to 121 warp threads / cm. When using a multifilament yarn with a fineness increased by approximately 3-10% from 855 to 915 dtex, the woven tape can be formed with a warp thread density of 100 to 110 warp threads / cm. A combination of increased yarn count and warp thread density also remains possible. In this way, a webbing made of fibers with reduced PCF can be obtained which, in the ready-to-install state, after completion of all manufacturing steps, has a breaking load of at least 23 kN, preferably at least 24 kN.The breaking load of the webbing can be determined according to FMVSS Regulation 209.

[0017] According to a further embodiment, the multifilament yarn has a nominal yarn count of 1100 dtex. The fabric belt can then be formed with an increased warp thread density of 77 to 101 warp threads / cm, preferably 92 to 101 warp threads / cm. When using a multifilament yarn with a count increased by approximately 3-10% from 1130 to 1210 dtex, the fabric belt can be formed with a warp thread density of 75 to 92 warp threads / cm. A combination of increased yarn count and warp thread density also remains possible. In this way, a webbing made of fibers with a reduced PCF can be obtained which, in the ready-to-install state, has a breaking load of at least 25 kN, preferably at least 27 kN.

[0018] In a further embodiment, the multifilament yarn has a nominal yarn count of 1670 dtex. In this case, the increased warp thread density of the woven tape is in a range from 56 to 75 warp threads / cm, preferably 70 to 75 warp threads / cm. When using a multifilament yarn with a count increased by approximately 3-10% from 1720 to 1840 dtex, the woven tape can be formed with a warp thread density of 54 to 68 warp threads / cm. A combination of increased yarn count and warp thread density also remains possible. In this way, a webbing made of fibers with a reduced PCF can be obtained which, in the ready-to-install state, has a breaking load of at least 25 kN, preferably at least 27 kN.

[0019] If the fabric tape is provided with a fabric edge, the specified warp thread density in the above embodiments is provided at least in a central region of the fabric tape in the transverse direction. However, the warp thread density can also be the same across the entire width of the fabric tape.

[0020] The weft threads of the fabric tape can be made of monofilament yarns and / or multifilament yarns. Fibers made from bio-based or recycled polymers can also be used for the weft threads. However, within the scope of the invention, it remains possible to form the weft threads from fibers obtained from petroleum-based raw materials.

[0021] The heat-setting of the fabric tape is preferably carried out at a maximum temperature of 225°C, particularly preferably in a range of 190°C to 220°C. The temperature used for heat-setting the fabric tape depends on the equipment used and the throughput speed of the fabric tape. To reduce the thermal stress on the webbing, a temperature approximately 5 to 10% lower than for the treatment of conventional webbing is selected, with the same throughput time. The lower heat-setting temperature results in a less pronounced drop in the breaking load of the fabric tape made of bio-based or recycled fibers.

[0022] Before heat-setting, the fabric tape can be piece-dyed. For this, the fabric tape is passed through a dye bath in a conventional dyeing device such as a padder and dyed to the desired depth of color.

[0023] To produce the fabric tape, a multifilament yarn can also be used that has already been dyed during the spinning process, for example, by adding color pigments such as carbon black particles to the polymer melt in the extruder. Using such spin-dyed yarns, dyeing the fabric tape is unnecessary.

[0024] Following heat-setting, the fabric tape can be subjected to a calendering stage, in which the fabric tape is passed between a pair of rollers and smoothed and optionally compacted. Through calendering, the thickness of the fabric tape is preferably adjusted to a range of 0.9 to 1.5 mm.

[0025] After heat-setting or calendering, the fabric tape can be treated with a friction-reducing finish. The friction-reducing finish can also be applied using a padder and with an oil pick-up (GPU) of 0.83 to 0.95 g / running meter, calculated for a mean (nominal) width of the fabric tape of 47 mm. Preferably, an application rate approximately 5 to 20% higher than for fabric tapes made from petroleum-based raw materials is used to reduce the mechanical stress on the webbing during its service life in the vehicle. The increased application rate of the friction-reducing finish can simultaneously reduce the stiffness of the webbing and the drop in breaking load compared to the raw fabric.

[0026] The fabric belt manufactured using multifilament fibers from bio-based and / or recycled raw materials can exhibit greater stiffness than comparable belts made from petroleum-based raw materials, which is further enhanced by the higher yarn count and / or the higher warp thread count. To reduce stiffness, additional mechanical processing can be performed at various stages of the manufacturing process. For this purpose, the fabric belt is guided over one or more rollers or rolls and bent, allowing the stiffness to be adjusted to a desired target value. The increased application of the friction-reducing treatment can also lead to reduced stiffness of the fabric belt.The thermoplastic polymer is preferably a thermoplastic polyester selected from the group consisting of a recycled polyester, a bio-based polyester, and combinations thereof, and optionally in combination with a petroleum-based polyester. Chemically and / or mechanically recycled polyesters can be used.

[0027] In particular, the polyester can be selected from the group consisting of a recycled polyethylene terephthalate (PET), a bio-based polyethylene terephthalate (PET) with a proportion of at least 30 wt.% monomers from renewable raw materials and a bio-based polyethylene terephthalate (PET) with a proportion of 100 wt.% monomers from renewable raw materials and combinations thereof.

[0028] The belt strap can preferably be coupled with a belt tensioner module, which can be activated mechanically, electrically or pyrotechnically in the event of an accident and can act on the belt strap.

[0029] The invention thus also relates to a belt webbing for use in a safety device in vehicles, which is obtainable by the method described above. In particular, the belt webbing is intended for use in a three-point belt.

[0030] Embodiments of the invention are described below, but should not be understood in a limiting sense.

[0031] Production of multifilament yarns from sustainable raw materials

[0032] To produce the fabric tape according to the invention, a multifilament yarn is provided that is formed from a thermoplastic polymer that is partially or completely produced using recycled and / or renewable raw materials. In principle, the invention is not limited to a specific thermoplastic polymer; rather, any thermoplastic polymer known in the art that is suitable as a component of a multifilament yarn for a webbing may be used.

[0033] According to the invention, the multifilament yarn is used to produce the warp threads of the fabric tape. Monofilament yarns and / or multifilament yarns made of the same thermoplastic polymer can be used to produce the weft threads. According to one aspect, the thermoplastic polymer is formed at least partially from a recycled polyester. Optionally, the thermoplastic polymer can also contain a portion of a petroleum-based polyester. Petroleum-based is understood below to mean a polyester produced from non-recycled starting materials and raw materials derived from petroleum or derivatives thereof.

[0034] According to a further aspect, the thermoplastic polymer can also be formed entirely from a recycled polyester.

[0035] The thermoplastic polymer can also be made from a bio-based polyester, i.e., a polyester made from renewable raw materials. Alternatively, the thermoplastic polymer can also contain a portion of a petroleum-based polyester.

[0036] According to a further aspect, the thermoplastic polymer can also be formed entirely from a bio-based polyester.

[0037] In addition, a three-component composition of the thermoplastic polymer is also conceivable, wherein the thermoplastic polymer comprises (A) a portion consisting of a bio-based polyester, (B) a portion consisting of a recycled polyester and (C) a portion consisting of a petroleum-based polyester.

[0038] Advantageously, the three-component composition comprises (A) a bio-based polyester in a proportion of 5 to 90 wt. %, (B) a recycled polyester in a proportion of 5 to 90 wt. %, and (C) a petroleum-based polyester in a proportion of 0 to 20 wt. %, each based on the total weight of the thermoplastic polymer, with components (A) to (C) together amounting to 100 wt. The use of raw materials from different sources offers the advantage that the PCF of the resulting thermoplastic polymer can be adjusted as required. A higher proportion of recycled polyester and / or bio-based polyester lowers the PCF, while an increase in the proportion of petroleum-based polyester leads to an increase in the PCF. The PCF of the thermoplastic polymer can be determined as described above.

[0039] Petroleum-based polyesters are already used to manufacture fabrics for webbing, so familiar specifications can be used.

[0040] According to another aspect, the recycled polyester is selected from the group consisting of a recycled polyethylene terephthalate (PET), polyethylene terephthalate (PET) with a content of at least 30 wt.% renewable raw materials and a polyethylene terephthalate (PET) with a content of 100 wt.% renewable raw materials and combinations thereof.

[0041] The recycled polyesters are preferably obtained from raw materials that can come from various sustainable sources. The raw materials preferably come from production waste, recycling systems, and / or residual waste.

[0042] For example, industrial production waste and packaging waste, such as from bottle return systems, can be used. From these wastes, almost pure raw materials can be obtained. However, it is also possible to use raw materials from tertiary waste, such as household waste, from which plastic waste can be separated using mechanical and chemical processes.

[0043] The recycled polyesters can be obtained from the above-mentioned sources through mechanical recycling.

[0044] In the following, material recycling refers to a process for recycling raw materials, especially plastics such as thermoplastic polymers, in which the polymer structure is retained during the recycling process. Material recycling comprises at least one step selected from the group consisting of sorting, comminution, washing, drying, post-polymerization, for example via solid-state polycondensation (SSP) and / or liquid-state polycondensation (LSP), extrusion, and regranulation.

[0045] The sorting of the raw materials to be recycled can be carried out either by the recycling system or by spectroscopic methods such as near-infrared spectroscopy (NIR). Spectroscopic analysis of the raw materials enables the separation of individual plastic types. The raw materials can be further separated using processes such as inductive and magnetic metal separation, air separation, and sieving. Depending on requirements, the separated plastic types can then be shredded. After shredding, wet mechanical processing follows, which consists of a multi-stage washing and separation process. This allows for the removal of foreign components such as food residues, minerals, and other organic residues. The individual target plastic types can be separated from one another based on their density in a tank or using sorting centrifuges.Similar methods for density separation are known from the prior art and can also be used. For plastics to be separated with similar density ranges, the aforementioned near-infrared spectroscopy can be used for targeted differentiation. The plastics can then be dried using mechanical and / or thermal processes. Vacuum drying is particularly suitable for this. The resulting single-grade recyclate can then be completely melted under pressure and temperature in an extruder. Finally, the melt is granulated and cooled.

[0046] Optionally, the thermoplastic polyesters can also be dissolved in a suitable solvent and freed from impurities, while preserving the molecular structure of the polymers. Using solvents specifically tailored to the specific plastic, the polymer can be dissolved while preserving its polymer structure. The resulting residue can be removed, for example, by filtration. After separation, the dissolved plastic can be precipitated, the solvent removed, and the plastic dried. The resulting plastics can then be granulated in an extruder.

[0047] The use of solvents offers the advantage that even heavily contaminated plastic waste can be recovered with a high quality. This allows for the removal of contaminants that would otherwise be difficult to separate from the plastic, as they do not dissolve in the solvent. Multilayer plastic laminates can also be separated. The choice of the appropriate solvent depends on the plastic to be recycled.

[0048] Another option for purifying and recycling thermoplastic polyesters is melt filtration. In this process, the raw material to be recycled is melted, and the resulting melt is filtered through a suitable filter element, thereby retaining impurities. The filter element can, in particular, be a metallic porous filter insert.

[0049] Melt filtration offers the technical advantage that impurities can be removed without the use of solvents to ensure the desired purity of the polymers.

[0050] Material recycling is particularly suitable for the processing of thermoplastic polymers such as polyesters from industrial production waste and packaging waste. Material recycling offers the advantage of the recycling process itself involving low processing effort. However, this is dependent on the appropriate quality of the input materials, which is ensured primarily by initial sorting.

[0051] To treat more heavily contaminated waste, raw material or chemical recycling processes can also be used. In these processes, the polymers, such as polyesters, are depolymerized using thermochemical or wet-chemical processes and broken down into their base monomers or other raw materials. Chemical recycling comprises at least one step from the group consisting of depolymerization, purification, polymerization, and regranulation. Solvolysis processes are particularly suitable, in which the polymers are converted into aqueous or organic solutions using suitable reagents such as acids, bases, alcohols, and amines, optionally at elevated temperature and pressure. The polymers are broken down into their base monomers or derivatives thereof, which can then be separated from the reaction mixture and purified separately. These can then be converted back into the desired polymers through polymerization.

[0052] The renewable raw materials are preferably monomers derived from biomass. These are referred to below as bio-based monomers.

[0053] In principle, the choice of bio-based monomer is not limited, and any known bio-based monomer that can be produced from biomass and is suitable for polymerization to form thermoplastic polymers such as polyester can be used. A thermoplastic polymer produced entirely or partially using bio-based monomers is therefore a bio-based thermoplastic polymer. The use of biomass to produce such polymers offers the advantage of being readily available, renewable, and sustainable under suitable cultivation conditions.

[0054] In an advantageous embodiment, the bio-based monomers are selected from the group consisting of aliphatic polycarboxylic acids, terephthalic acid, isophthalic acid and aliphatic polyols, in particular monoethylene glycol, and combinations thereof.

[0055] Other bio-based monomers that can be obtained from renewable raw materials include succinic acid from glucose through fermentation, valeric acid from the hydrolysis step of biogas plants, pimelic acid from castor oil, azelaic acid from oleic acid through oxidative conversion, and dodecanedioic acid from coconut oil or palm kernel oil and fermentation of capric acid. Starting from these monomers, the corresponding diols can be obtained through biotechnological processes and, optionally, further chemical conversion. Sugar-containing plants, starch-containing plants, lignocellulose, and / or agricultural waste are particularly suitable as biomass. Such plants are particularly suitable because they have a particularly high proportion of glycosidically linked sugar building blocks, such as starch.

[0056] Examples of suitable plants include potatoes, sugar beets, wheat and maize.

[0057] Also suitable are oil crops, including oilseeds and oil-containing plants and parts of plants.

[0058] Seeds of the castor oil plant, for example, are suitable as oil crops.

[0059] The starting raw materials polysaccharides, especially sugar and starch, lignin, cellulose, and / or vegetable oil, especially castor oil, can advantageously be obtained from the biomass, optionally by fermentation and / or catalytic processes. More specifically, the starch contained in the biomass can be converted into sugar. Sugars are understood to include, in particular, all types of pentoses such as ribose, arabinose, and xylose; hexoses such as fructose, glucose, mannose, galactose, fucose, and rhamnose; and derivatives thereof, such as derived amines, amides, esters, and deoxygenated compounds.

[0060] The starting raw materials in question here can be used for the production of the bio-based monomers.

[0061] The steps for producing thermoplastic bio-based polymers from renewable raw materials include in particular the formation of bio-based monomers from biomass by oxidation or reduction, fermentation, chemical conversion and / or hydrolysis, as well as polymerization of the monomers and granulation of the polymers produced therefrom.

[0062] In this way, for example, the alcohols and dicarboxylic acids required for the production of polyesters can be obtained.

[0063] In one aspect, the thermoplastic polymer is BioPET100%, which is provided by the following steps:

[0064] Hydrolyzing biomass to obtain a sugar-starch mixture; fermenting the sugar-starch mixture to form bioethanol;

[0065] Dehydrating bioethanol to obtain ethylene;

[0066] oxidizing ethylene with oxygen to obtain ethylene oxide;

[0067] Hydrolyzing ethylene oxide to obtain monoethylene glycol; optionally a) acid-catalyzed dehydration of sugars to (hydroxymethyl)furfural (HMF), followed by its hydrogenation to 2,5-dimethylfuran; addition of 2,5-dimethylfuran to ethylene and subsequent dehydration to obtain p-xylene; or b) catalytic hydrogenation of hydrolyzed biomass to obtain deoxygenated feedstock, which is subsequently converted into p-xylene by a refinery process; catalytic oxidation of p-xylene to terephthalic acid; and

[0068] Polycondensation of monoethylene glycol and terephthalic acid to obtain the thermoplastic polymer BioPET100%.

[0069] The resulting thermoplastic polymer, BioPET100%, consists essentially, i.e., 100%, of renewable raw materials, namely monoethylene glycol and terephthalic acid. BioPET100% can also be used directly in the production of webbing.

[0070] The thermoplastic polymer can also be BioPET30%, in which bio-based monoethylene glycol and terephthalic acid conventionally produced from petroleum-based raw materials are provided and reacted with each other in a subsequent step in a polycondensation to obtain BioPET30%.

[0071] The designation BioPET30% is merely the trivial name of the resulting thermoplastic PET polymer. Due to the stoichiometry of the polycondensation, the bio-based monoethylene glycol in the PET polymer is present in a proportion of 31.2 wt.% and the terephthalic acid in a proportion of 68.8 wt.%. The same process can be used to produce bio-based monoethylene glycol as described above for BioPET100%.

[0072] The process described below can be used to produce a multifilament yarn from recycled PET. The PET required to produce the multifilament yarn can be recycled using a material recycling process, so the polymer structure remains unchanged. PET bottles can be used as the starting raw material for the multifilament yarn.

[0073] In a first step, PET beverage bottles are removed from a collection system to remove film, metal, and other plastics, sorted, and then mechanically shredded into flakes. This is followed by a hot-washing process and subsequent vacuum drying. The resulting flakes are further sorted and then regranulated. The regranulate is finally spun into a multifilament yarn using a melt spinning process.

[0074] The multifilament yarn made from recycled PET has essentially the same properties as a multifilament yarn spun from non-recycled raw materials with a comparable fineness and the same number of filaments.

[0075] In general, bio-based polymers as well as recycled polymers can be post-polymerized to achieve a degree of polymerization suitable for an intended application.

[0076] The recycled and bio-based polymers produced from the process described above, especially polyester, can be used as base polymers in the production of webbing.

[0077] The resulting base polymers are melt-spun using known technical yarn production processes, as described, for example, in Ulmann's Encyclopedia of Industrial Chemistry, Vol. 13, pages 465 ff (2003). This produces multifilament yarns made entirely or partially from recycled or renewable raw materials. The multifilament yarn used for the warp threads in the process according to the invention has a yarn count of 750 dtex to 2000 dtex, preferably 800 dtex to 1900 dtex.

[0078] The tenacity of the multifilament yarn is preferably at least 60 cN / tex, and preferably in the range of 60 to 85 cN / tex. The breaking load used to calculate the tenacity of the yarn can be determined according to DIN EN ISO 2062, and the tenacity according to DIN EN ISO 2060.

[0079] The multifilament yarn produced in this way can be further processed for the subsequent weaving process, for example, by applying a protective coating or sizing. This can be achieved, in particular, by finishing the multifilament yarn.

[0080] Production of fabric tapes from sustainable raw materials

[0081] The method according to the invention is described in more detail below using exemplary embodiments with reference to the accompanying drawings. In the drawing, the sole example shows:

[0082] Fig. 1 schematically shows a device for carrying out the method according to the invention and producing a belt strap according to the invention.

[0083] Fig. 1 schematically illustrates a device 10 for producing a belt strap 11 for a safety system in vehicles.

[0084] First, a fabric tape 12 is woven from the multifilament yarn described above in a weaving device known per se and not shown in detail here. It then passes into a feed device 14, 16. The thickness of the fabric tape 12 can be influenced by the number of warp threads and the weft thread density. The higher the number of warp threads and the weft thread density, the thicker the fabric tape 12 becomes and the higher the breaking strength of the fabric tape 12. The weft thread density is typically in the range of 55 to 75 double threads / 10 cm.

[0085] At least the warp threads are preferably formed from a thermoplastic polyester, particularly preferably polyethylene terephthalate (PET), wherein the polyester was produced partially or entirely using recycled and / or renewable raw materials. The thermoplastic polyester is particularly preferably a recycled PET, a bio-based PET with a proportion of at least 30 wt.% monomers from renewable raw materials, and / or a bio-based PET with a proportion of 100 wt.% monomers from renewable raw materials.

[0086] After weaving, the fabric strip 12 can be dyed in a dyeing device 18. The dyeing device 18 itself is well known in the art. After dyeing, the fabric strip can be subjected to a first wash.

[0087] The fabric tape 12 then passes into a heating device 20, in which the fabric tape 12 is heated to a maximum temperature of 225°C for heat-setting. Specifically, the fabric tape 12 is heated to 190°C to 220°C for approximately 1 to 2 minutes. In the heating device 20, the fabric tape 12 can shrink or stretch, which can change the properties of the fabric tape 12, particularly the breaking load and elongation.

[0088] The fabric belt 12 then runs through a calender 24. The calender 24 comprises at least one pair of rollers consisting of two metal rollers 26, 28, between which the fabric belt 12 is passed.

[0089] In the calender 24, the fabric belt 12 is compressed to the desired thickness. This also smoothes the fabric belt 12. The thickness of the fabric belt 12 after calendering is, for example, between 0.9 mm and 1.5 mm.

[0090] After calendering, the fabric belt 12 is washed in a washing device 30 and then fed to an application device 32, in which a friction-reducing finish is applied to the surface of the fabric belt 12. The application device 32 as such is known in the art. The friction-reducing finish is preferably applied at an application rate (OPU) of 0.83 to 0.95 g / linear meter, calculated for a fabric belt width (nominal value) of 47 mm. The application rate (nominal value) of the friction-reducing finish for fabric belts made of petroleum-based fibers is approximately 0.79 g / linear meter. In comparison, the application rate for the fabric belts produced according to the invention using recycled or bio-based fibers is preferably increased by 5 to 20%. After the friction-reducing finish has been applied, the fabric belt 12 can be passed through a dryer 34.

[0091] To adjust the stiffness, the fabric belt can be mechanically processed. For example, a roller arrangement 29 can be provided downstream of the calender 24, where the belt is bent several times, thereby reducing the stiffness. The fabric belt 12 is typically manufactured as an endless body. To complete a belt 11, the fabric belt 12 is cut to the desired length.

[0092] The belt webbing 11 thus obtained can optionally be mounted with further components in a belt retractor housing (not shown) to obtain a three-point belt of a safety device.

Claims

Patent claims 1. A method for producing a belt strap (11) for a safety device in vehicles, the method comprising the following steps: Weaving a multifilament yarn into a fabric tape (12) with warp and weft threads made of the multifilament yarn, wherein at least the warp threads are formed from the multifilament yarn; Thermosetting the fabric tape (12) in a heating device (20); and Cutting the fabric tape (12) into a belt tape of defined length, wherein the multifilament yarn is formed from at least one thermoplastic polymer which is produced partially or completely using recycled and / or renewable raw materials and wherein the warp threads have a yarn count of 750 dtex to 2000 dtex, and / or wherein the fabric tape is formed with a warp thread density of 50 to 125 warp threads / cm.

2. Method according to claim 1, characterized in that the multifilament yarn has a yarn count with a nominal value of 830 dtex and a warp thread density in a range of 103 to 121 warp threads / cm, and / or a yarn count of 855 to 915 dtex with a warp thread density of 100 to 110 warp threads / cm.

3. Method according to claim 1, characterized in that the multifilament yarn has a yarn count with a nominal value of 1100 dtex and a warp thread density of 77 to 101 warp threads / cm, and / or a yarn count of 1130 to 1210 dtex and a warp thread density of 75 to 92 warp threads / cm.

4. The method according to claim 1, characterized in that the multifilament yarn has a yarn count with a nominal value of 1670 dtex and a warp thread density in a range of 56 to 75 warp threads / cm, and / or a yarn count of 1720 to 1840 dtex and a warp thread density of 54 to 68 warp threads / cm.

5. Method according to one of the preceding claims, characterized in that the heat-setting takes place at a temperature of at most 225 °C, preferably from 190 °C to 220 °C.

6. Method according to one of the preceding claims, characterized in that the multifilament yarn is provided with a friction-reducing finish, preferably with an application quantity of 0.83 to 0.95 g / running meter, calculated on a width of the fabric tape with a nominal value of 47 mm.

7. A method according to any one of the preceding claims, characterized in that the thermoplastic polymer is selected from the group consisting of a recycled polyester, a bio-based polyester and combinations thereof, and optionally in combination with a petroleum-based polyester.

8. The method according to claim 7, characterized in that the polyester is selected from the group consisting of a recycled polyethylene terephthalate, a bio-based polyethylene terephthalate with a proportion of at least 30 wt.% monomers from renewable raw materials and a bio-based polyethylene terephthalate with a proportion of 100 wt.% monomers from renewable raw materials and combinations thereof.

9. Webbing (11) obtainable by a process according to the preceding claims 1 to 8, wherein the webbing (11) has warp and weft threads, wherein at least the warp threads are formed from the multifilament yarn, wherein the multifilament yarn is formed from a thermoplastic polymer which is partially or completely produced using recycled and / or renewable raw materials, and wherein the warp threads have a yarn fineness of 750 dtex to 2000 dtex, and / or the webbing is formed with a warp thread density of 50 to 125 warp threads / cm.

10. Belt strap according to claim 9, characterized in that the warp threads (i) have a yarn count of 830 dtex and a warp thread density in the range of 103 to 121 warp threads / cm and / or a yarn count of 855 to 915 dtex with a warp thread density of 100 to 110 warp threads / cm and the breaking load of the webbing is at least 23 kN, or (ii) have a nominal yarn count of 1100 dtex and a warp thread density of 77 to 101 warp threads / cm and / or a yarn count of 1130 to 1210 dtex and a warp thread density of 75 to 92 warp threads / cm and the breaking load of the webbing is at least 25 kN, or (iii) have a yarn count of 1670 dtex and a warp thread density in a range of 56 to 75 warp threads / cm, and / or a yarn count of 1720 to 1840 dtex and a warp thread density of 54 to 68 warp threads / cm and the breaking load of the webbing is at least 25 kN.

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