Method for manufacturing a webbing and strap

Abstract

To manufacture a webbing (11) for a safety device in vehicles, a multifilament yarn is woven into a woven tape (12) with warp and weft threads, and the woven tape (12) is thermoset. The multifilament yarn is made of a thermoplastic polymer that is produced partially or entirely 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, with the warp thread density of the woven tape ranging from 50 to 125 warp threads / cm. The woven tape (12) is cut to form a webbing (11) of a defined length.

Description

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.A safety system in vehicles with a belt strap serves to protect a vehicle occupant from injuries in the event of accidents of a wide variety of types. The belt strap restrains the vehicle occupant in the event of severe decelerations, so that the vehicle occupant participates in the vehicle deceleration as early as possible and contact with objects in the vehicle, such as a steering wheel or a dashboard, is prevented.A number of plastics are used to produce the belt straps. However, the plastics used hitherto are petroleum-based and in some cases cause considerable greenhouse gas emissions along their value chain. The CO 2 released by the value chain contributes to the greenhouse effect responsible for the global climate heating. Such greenhouse gas emissions are quantified with 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) stands for those greenhouse gas emissions which arise during the production of products via their use until disposal. The aim is therefore to improve the environmentally compatible handling of plastics even in the area of safety-relevant components and to reduce the PCF.The production of bio-based or recycled plastics is already known per se. The use of bio-based or recycled plastics in safety devices for vehicles has not yet become established with regard to the required reliability of the components. In particular, the mechanical properties of belt straps made of bio-based or recycled plastics may be subject to undesired changes in the manufacturing process.The object of the invention is thus to avoid the above disadvantages and to provide a method for producing belt straps for safety systems based on lasting raw materials.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.Advantageous embodiments of the method according to the invention are specified in the dependent claims, which can be combined with one another as desired.The invention relates to a method for producing a belt strap for a safety device in vehicles, having the following steps:weaving a multifilament yarn into a woven tape having warp and weft yarns, at least the warp yarns being formed from the multifilament yarn;optionally dyeing the fabric tape;thermofixing the fabric ribbon in a heater;optionally calendering the fabric belt;optionally applying friction reducing finish to the fabric belt; andcutting the fabric strip into a belt strap of defined length;wherein the multifilament yarn is formed from a thermoplastic polymer partially or completely produced using recycled and / or renewable raw materials, and wherein at least the warp yarns have a yarn fineness of 750 dtex to 2000 dtex, and wherein the fabric band is formed with a warp yarn density of 50 to 125 warp yarns / cm.Recourse to recycled or renewable raw materials for the production of thermoplastic polymers and their subsequent processing into multifilament yarns makes it possible to produce fabric-based components of security systems in vehicles permanently and with reduced PCF. This makes it possible to make a substantial contribution to the climate-friendly production of these components. Moreover, the dependence of the production of fossil raw materials can be further reduced. The detachment of fossil starting materials in the production can also involve the reduction of energy-intensive chemical reactions and thus contribute to making the proposed method more resource-saving, durable and environmentally friendly.The invention is based on the finding that recycled and renewable materials are also suitable for producing safety-relevant components in a vehicle. This is not a matter of course in view of the high demands made on a webbing. The inventors herein have recognized that thermoplastic polymers such as polyesters made of renewable or recycled materials can be integrated into the production of belt straps with the aid of the method according to the invention without impairing the safety-relevant properties of these components.In particular, it has been recognized that the mechanical properties of the webbing are subject to more severe changes during the manufacturing process. For example, a raw state bio-based or recycled polyester fabric belt exhibits a tensile strength comparable or even improved with petroleum-based polyester fabric belts of equal yarn fineness and warp density. After heat setting, however, the tensile strength of the woven tape of recycled or bio-based yarns may drop far more than for woven tapes obtained from petroleum-based multifilament yarns. This gives rise to the risk that the manufacturer's specifications concerning the mechanical load-bearing capacity of the belt straps cannot be complied with reliably when using multifilament yarns made from sustainable raw materials.The method according to the invention therefore provides that, for producing belt straps from biobased or recycled raw materials, the yarn fineness is increased by about 3 to 10% compared to conventional petroleum-based multifilament yarns. Alternatively or additionally, the warp thread density can likewise be increased by approximately 3 to 10% compared to conventional belt straps. According to the invention, therefore, at least the warp threads which run in the longitudinal direction in the finished belt strap should have a fineness of between 750 dtex and 2000 dtex, and / or the warp thread density should lie in a range of 50 to 125 warp threads / cm. This ensures that the manufacturer specifications with respect to the mechanical load capacity of the belt straps can be fulfilled not only in the raw state, but also after all processing steps.According to one embodiment, the multifilament yarn has a yarn fineness with a nominal value of 830 dtex. "nominal value" here and hereinafter refers to the nominal value of the manufacturer specification and includes usual manufacturing tolerances. The manufacturing tolerances are usually about ±1.5%. In this case, the increased warp density of the fabric tape is in a range of 103 to 121 warp / cm, preferably 112 to 121 warp / cm. When using a multifilament yarn having a fineness of 855 to 915 dtex increased by about 3-10%, the woven fabric band can be formed with a warp density of 100 to 110 warp threads / cm. A combination of increased yarn fineness and warp thread density also remains possible. In this way, a belt strap of fibers with reduced PCF can be obtained which, in the ready-to-install state, after completion of all production 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 the FMVSS specification 209.According to a further embodiment, the multifilament yarn has a yarn fineness with a nominal value of 1100 dtex. The fabric tape can then be formed with an increased warp density of 77 to 101 warp yarns / cm, preferably 92 to 101 warp yarns / cm. When using a multifilament yarn having a fineness of 1130 to 1210 dtex increased by about 3-10%, the woven fabric band can be formed with a warp density of 75 to 92 warp threads / cm. A combination of increased yarn fineness and warp thread density also remains possible. In this way, a belt strap of fibers with 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.In a further embodiment, it is provided that the multifilament yarn has a yarn fineness with a nominal value of 1670 dtex. In this case, the increased warp density of the fabric tape is in a range of 56 to 75 warp yarns / cm, preferably 70 to 75 warp yarns / cm. When using a multifilament yarn having a fineness of 1720 to 1840 dtex increased by about 3-10%, the woven fabric band can be formed with a warp density of 54 to 68 warp yarns / cm. A combination of increased yarn fineness and warp thread density also remains possible. In this way, a belt strap of fibers with 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.In the above embodiments, if the fabric band is provided with a fabric edge, the indicated warp density is provided at least in a middle portion of the fabric band in the transverse direction. The warp thread density can, however, also be the same over the entire width of the fabric band.The weft threads of the fabric tape may be made of monofilament yarns and / or multifilament yarns. Fibers of bio-based or recycled polymers can also be used for the weft threads. However, it remains possible within the meaning of the invention to form the weft threads from fibers which have been obtained from petroleum-based raw materials.The heat-setting of the fabric tape is preferably carried out at a temperature of not more than 225° C., particularly preferably in a range from 190° C. to 220° C. The temperature used for heat-setting the fabric tape is dependent on the apparatus used and the throughput speed of the fabric tape. In order to reduce the thermal load on the belt strap, a temperature reduced by about 5 to 10% compared to the treatment of conventional belt straps is selected with the same cycle time. The lower temperature of heat setting causes a less severe drop in the breaking load of the bio-based or recycled fiber fabric tape.Before heat setting, the fabric tape can be subjected to piece dyeing. For this purpose, the fabric tape is passed through a dyeing bath in a dyeing apparatus known per se, such as a padding machine, and dyed to the desired depth of color.For producing the woven fabric tape, it is also possible to use a multifilament yarn which has already been dyed in the spinning process, for example by adding color pigments such as carbon black particles to the polymer melt in the extruder. When such spin-dyed yarns are used, the dyeing of the fabric tape can be omitted.Following heat-setting, the fabric belt can be subjected to a calendering stage in which the fabric belt is passed between a pair of rollers and smoothed and optionally compacted. By calendering, the thickness of the fabric tape is preferably adjusted to a range of 0.9 to 1.5 mm.After heat setting or calendering, the fabric belt can be provided with friction-reducing equipment. The application of the friction-reducing equipment can likewise be carried out in a paddy and can be carried out with an application quantity (oil pick-up; OPU) of 0.83 to 0.95 g / running meter, calculated to an average width (nominal value) of the fabric strip of 47 mm. Preferably, an application quantity increased by about 5 to 20% compared to fabric belts made of petroleum-based raw materials is provided in order to reduce the mechanical load on the belt belt belt during the use time in the vehicle. With the increased application rate of the friction-reducing equipment, the stiffness of the belt strap can be reduced at the same time and the breaking load drop can be reduced compared to the raw fabric.The fabric tape produced using multifilament fibers from bio-based and / or recycled raw materials can have a higher stiffness than comparable belt tapes from petroleum-based raw materials, which is even increased due to the higher yarn fineness and / or the higher warp thread count. To reduce the stiffness, additional mechanical processing can be carried out at various stages of the manufacturing process. For this purpose, the fabric strip is guided over one or more rollers and bent, whereby the stiffness can be adjusted to a desired set value. The increased application rate of the friction-reducing equipment can also lead to a 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 may be used.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.The belt strap can preferably be coupled to a belt tensioner module, which in the event of an accident can be activated mechanically, by electric motor or pyrotechnically and can act on the belt strap.The invention therefore also relates to a belt strap for use in a safety device in vehicles, which belt strap can be obtained by the method described above. In particular, the belt strap is provided for use in a three-point belt.Exemplary embodiments of the invention are described below, which, however, should not be understood in a limiting sense.Production of multifilament yarns from sustainable raw materialsTo produce the fabric tape according to the invention, a multifilament yarn is provided which is formed from a thermoplastic polymer which is produced partly or completely using recycled and / or renewable raw materials.In principle, the invention is not limited to a specific thermoplastic polymer, but any thermoplastic polymer known in the art which is suitable as a constituent of a multifilament yarn for a belt strap can be used.The multifilament yarn is used according to the invention for producing the warp threads of the fabric tape. Monofilament yarns and / or multifilament yarns made of the same thermoplastic polymer can be used for the production of the weft threads. In one aspect, the thermoplastic polymer is at least partially formed from a recycled polyester. Optionally, the thermoplastic polymer may also contain a portion of a petroleum-based polyester. In the following, petroleum-based is understood to mean a polyester which is produced from non-recycled starting materials and raw materials which originate from petroleum or derivatives thereof.According to a further aspect, however, the thermoplastic polymer can also be formed completely from a recycled polyester.The thermoplastic polymer can likewise be formed from a biobased polyester, i.e. from a polyester which has been produced from renewable raw materials. Optionally, the thermoplastic polymer may also contain a portion of a petroleum-based polyester.According to a further aspect, the thermoplastic polymer can, however, also be formed completely from a biobased polyester.In addition, a three-component composition of the thermoplastic polymer is also conceivable, wherein the thermoplastic polymer comprises (A) a fraction consisting of a bio-based polyester, (B) a fraction consisting of a recycled polyester and (C) a fraction consisting of a petroleum-based polyester.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 %, in each case based on the total weight of the thermoplastic polymer, wherein components (A) to (C) together make up 100 wt %.The use of raw materials from different sources offers the advantage that the PCF of the thermoplastic polymer formed therefrom 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 results in an increase in the PCF. The PCF of the thermoplastic polymer can be determined as described above.Petroleum-based polyesters are already used for the production of fabrics for belt straps, so that known specifications can be used.In another aspect, the recycled polyester is selected from the group consisting of a recycled polyethylene terephthalate (PET), polyethylene terephthalate (PET) having a proportion of at least 30 wt % renewable raw materials, and a polyethylene terephthalate (PET) having a proportion of 100 wt % renewable raw materials, and combinations thereof.Advantageously, the recycled polyesters are obtained from starting raw materials which may be derived from various sustainable sources. The starting raw materials advantageously originate from production waste, recycling systems and / or residual waste.For example, industrial production wastes and packaging wastes such as bottle retrieval systems can be used. From these waste materials, almost single-grade raw materials can be obtained. However, it is also possible to use starting raw materials from tertiary waste, such as domestic waste, from which waste plastics can be separated by mechanical and chemical methods.The recycled polyesters can be obtained from the above mentioned sources by material recycling.Material recycling is understood below to mean a method for recycling starting raw materials, in particular plastics such as thermoplastic polymers, in which the polymer structure is retained during the recycling process.Recycling of material comprises at least one step selected from the group consisting of sorting, comminution, washing, drying, postpolymerization, for example via solid state polycondensation (SSP) and / or liquid state polycondensation (LSP), extrusion and regranulating.The sorting of the starting raw materials to be recycled can be carried out either by the recycling system or by spectroscopic methods such as near infrared spectroscopy (NIR). The spectroscopic examination of the starting raw materials enables in particular a separation of the individual types of plastics from one another. The starting raw materials can be separated from one another in an assisting manner by processes of inductive and magnetic metal separation, wind classification and screening. Depending on requirements, the types of plastics separated from one another can now be comminuted. After comminution, wet-mechanical treatment is carried out, which is composed of a multistage washing and separation process. This allows foreign constituents such as food residues, minerals and other organic residues to be removed in particular. The individual types of target plastics can be separated from one another by means of their density in a basin or by sorting centrifuges. Similar methods of density separation are known in the art and may also be used. In the case of similar density ranges of the plastics to be separated, the aforementioned near infrared spectroscopy can be used for the targeted differentiation. The plastics can then be dried by mechanical and / or thermal methods. Vacuum drying is particularly suitable for this purpose. The pure-grade recyclate obtained in this way can now be completely melted under pressure and temperature in an extruder. Finally, the melt is granulated and cooled.Alternatively, the thermoplastic polyesters can also be dissolved in a suitable solvent and freed from impurities, while the molecular structure of the polymers is retained. By means of special solvents matched to the respective plastic, the latter can be brought into solution, the polymer structure being retained. The residue thus obtained can be removed, for example, by filtration. The solubilized plastic may be precipitated after separation, the solvent removed, and the plastic dried. The plastics obtained in this way can then be granulated in an extruder.The use of solvents offers the advantage that even heavily contaminated waste plastics can be recovered in a high quality. This allows impurities which are otherwise difficult to separate from the plastic to be removed, since these do not dissolve in the solvent. Multilayer plastic laminates can likewise be separated. The choice of the suitable solvent depends on the plastic to be recycled.A further possibility for purifying and recycling thermoplastic polyesters is melt filtration. In this case, the starting raw material to be recycled is melted and the melt formed is filtered by a suitable filter element, impurities being retained. The filter element can be, in particular, a metallic porous filter insert.Melt filtration offers the technical advantage that impurities can be removed even without the use of solvents in order to ensure the desired purity of the polymers.Recycling of the material is suitable in particular for processing thermoplastic polymers such as polyesters from industrial production waste and from packaging waste. Recycling of material offers the advantage that the recycling process per se involves low processing costs. However, this is linked to a corresponding quality of the starting materials, which is ensured in particular by the initial sorting.To process more heavily contaminated wastes, raw material or chemical recycling processes can also be used, in which the polymers, for example polyesters, are depolymerized by thermochemical or wet chemical processes and split into their base monomers or other base substances. The chemical recycling includes at least one step selected from the group consisting of depolymerization, purification, polymerization and regranulation.Especially suitable are solvolysis processes, in which the polymers are converted into aqueous or organic solutions with suitable reagents such as acids, bases, alcohols and amines, optionally under elevated temperature and pressure. The polymers are thereby broken down into their basic monomers or derivatives thereof, which can then be separated from the reaction mixture and purified separately. These can then be reacted again to give the desired polymers by polymerization.The renewable raw materials are advantageously monomers obtained from biomass. These are referred to below as biobased monomers.In principle, the selection of the bio-based monomer is not restricted and any known bio-based monomer can be used which can be produced from biomass and is suitable for the polymerization to form thermoplastic polymers such as polyesters. A thermoplastic polymer produced wholly or partly using bio-based monomers is thus a bio-based thermoplastic polymer. The use of biomass for the production of such polymers offers the advantage that it is available at will, renewable and lasting under suitable cultivation conditions.In an advantageous embodiment, the biobased 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.Further biobased monomers which can be obtained from renewable raw materials are succinic acid from glucose by fermentation, valeric acid from the hydrolysis step of biogas plants, pimelic acid from castor oil, azelaic acid from oleic acid by 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 by biotechnological processes and optionally further chemical reactions.Suitable biomasses are, in particular, sugar-containing plants, starch-containing plants, lignocellulose and / or agricultural waste. Such plants are particularly suitable since they have a particularly high proportion of sugar building blocks linked glycosidically to one another, such as starch, for example.Examples of suitable plants are potatoes, sugar beets, wheat and corn.Oil crops including oilseeds and oil-containing plants and plant parts are also suitable.Suitable oil fruits are, for example, seeds of the castor tree.The starting raw materials polysaccharides, in particular sugar and starch, lignin, cellulose and / or vegetable oil, in particular castor oil, can advantageously be obtained from the biomass, optionally by means of fermentation and / or catalytic processes. More specifically, the starch contained in the biomass can be converted to sugar. Sugars are understood in particular to mean 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.The starting raw materials in question here can be used for the preparation of the biobased monomers.The steps for producing the thermoplastic bio-based polymers from renewable raw materials comprise in particular the formation of bio-based monomers from biomass by oxidation or reduction, fermentation, chemical conversion and / or hydrolysis, and also polymerization of the monomers and granulation of the polymers produced therefrom.In this way, for example, the alcohols and dicarboxylic acids required for the preparation of polyesters can be obtained.In one aspect, the thermoplastic polymer is BioPET100%, provided by the following steps:hydrolyzing biomass to obtain a sugar-starch mixture;fermenting said sugar-starch mixture to form bioethanol;dehydrating bioethanol to obtain ethylene;oxidizing ethylene with oxygen to obtain ethylene oxide;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; adding 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 reacted in p-xylene by a refinery process;catalytically oxidizing p-xylene to terephthalic acid; andpolycondensing monoethylene glycol and terephthalic acid to obtain the thermoplastic polymer BioPET100%.The thermoplastic polymer BioPET100% obtained in this way consists essentially, i.e. to the extent of 100%, of renewable raw materials, namely monoethylene glycol and terephthalic acid. BioPET100% can also be used directly in the manufacture of straps.The thermoplastic polymer can also be BioPET30%, in which biobased monoethylene glycol and terephthalic acid conventionally produced from petroleum-based raw materials are provided and react with one another in a polycondensation in a subsequent step to obtain BioPET30%.The term BioPET30% is only the common name of the thermoplastic PET polymer obtained. Due to the stoichiometry of the polycondensation, the biobased monoethylene glycol is present in the PET polymer in a proportion of 31.2% by weight and the terephthalic acid in a proportion of 68.8% by weight.For the preparation of biobased monoethylene glycol, the same process as described above for BioTM100% can be used.For producing a multifilament yarn from recycled PET, the method described below can be used. The PET required for producing the multifilament yarn can be recycled by means of a material recycling process, so that the polymer structure is not changed. As starting raw material for the multifilament yarn, PET bottles can be used.In a first step, PET beverage bottles are freed from foils, metals and other plastics from a collection system, sorted and subsequently mechanically comminuted to flakes. This is followed by a hot washing process with subsequent vacuum drying. The flakes obtained are re-sorted again and then re-granulated. The regranules are finally spun in a melt spinning process to form a multifilament yarn.The multifilament yarn produced from recycled PET has essentially the same properties as a multifilament yarn spun with comparable fineness and the same filament number from non-recycled starting raw materials.Generally, the bio-based polymers as well as the recycled polymers may still be post-polymerized to achieve a degree of polymerization suitable for an intended application.The recycled and bio-based polymers, in particular polyesters, produced from the above-described process can be used as base polymers in the production of belt straps.The melt spinning of the base polymers obtained in this way is carried out by known industrial processes for yarn production, as described, for example, in Ulmann's Encyclopedia of Industrial Chemistry, Vol. 13, pages 465 et seq. (2003). In this way multifilament yarns are obtained which are wholly or partly made from recycled or renewable raw materials.The multifilament yarn used for the warp yarns in the method according to the invention has a yarn fineness of 750 dtex to 2000 dtex, preferably of 800 dtex to 1900 dtex.The fineness (tenacity) of the multifilament yarn is preferably at least 60 cN / tex, and is preferably in a range of 60 to 85 cN / tex. The breaking load of the yarn used to calculate the fineness of the yarn can be determined according to the standard DIN EN ISO 2062 and the fineness according to the standard DIN EN ISO 2060.The multifilament yarn produced in this way can be processed for the later weaving process, for example by applying a protective layer or sizing. This can be effected in particular by avivating of the multifilament yarn.Production of Fabric Tapes from Sustainable Raw MaterialsThe method according to the invention is described in more detail below with reference to exemplary embodiments with reference to the attached drawing. The only figure shows:FIG. 1 schematically shows a device for carrying out the method according to the invention and producing a belt strap according to the invention.FIG. 1 schematically illustrates a device 10 for manufacturing a belt strap 11 for a safety system in vehicles.First, a woven tape 12 is woven from the above-described multifilament yarn in a weaving device known per se and not shown in detail here and then reaches a feeding device 14, 16. The higher the number of warp yarns and the weft yarn density, the thicker the fabric tape 12 and the higher the breaking strength of the fabric tape 12, the weft yarn density is usually in a range of 55 to 75 double yarns / 10 cm.At least the warp threads are preferably formed from a thermoplastic polyester, particularly preferably polyethylene terephthalate (PET), wherein the polyester has been partially or completely produced 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% by weight of monomers from renewable raw materials and / or a bio-based PET with a proportion of 100% by weight of monomers from renewable raw materials.After weaving, the fabric tape 12 can be dyed in a dyeing apparatus 18. The dyeing apparatus 18 per se is sufficiently known from the prior art. After dyeing, the fabric tape can be subjected to a first wash.The fabric belt 12 then runs into a heating device 20, in which the fabric belt 12 is heated to a temperature of at most 225° C. for heat setting. In particular, the fabric belt 12 is heated to 190° C. to 220° C. for approximately 1 to 2 min. In the heating device 20, the fabric band 12 can shrink or stretch, as a result of which the properties of the fabric band 12, in particular the breaking load and the stretching, can change.The fabric belt 12 then passes 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.In calender 24, the fabric belt 12 is compressed to the desired thickness. In this way, a smoothing of the fabric band 12 is also achieved. The thickness of the fabric strip 12 after calendering is, for example, between 0.9 mm and 1.5 mm.After calendering, the fabric tape 12 is washed in a washer 30 and then fed to an applicator 32 in which friction reducing finish is applied to the surface of the fabric tape 12. The applicator 32 as such is known in the art. The application of the friction-reducing equipment is preferably carried out with an application quantity (OPU) of 0.83 to 0.95 g / pass meter, calculated to a width (nominal value) of the fabric band of 47 mm. The application rate (nominal value) of the friction-reducing equipment is about 0.79 g / LaMeter for petroleum-based fibre fabric belts. In comparison, the application rate for the fabric tapes produced according to the invention using recycled or bio-based fibers is preferably increased by 5 to 20%. After application of the anti-friction finish, the fabric belt 12 may be passed through a dryer 34.To adjust the stiffness, the fabric tape can be mechanically worked. For example, a roll arrangement 29 can be provided after the calender 24, on which the belt strap is bent several times and the stiffness is thereby reduced.The fabric belt 12 is usually manufactured as an endless body. To complete a belt strap 11, the fabric strap 12 is cut to the desired length.The webbing 11 thus obtained may be selectively mounted with other components in a webbing retractor housing (not shown) to obtain a three-point webbing of a safety device.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Cited Non-Patent LiteratureUlmann's Encyclopedia of Industrial Chemistry, Vol. 13, pages 465 et seq. (2003

[0074]

Claims

A method for manufacturing a webbing (11) for a safety device in vehicles, the method comprising the steps of: weaving a multifilament yarn into a fabric band (12) with warp and weft yarns from the multifilament yarn, wherein at least the warp yarns are formed from the multifilament yarn; heat-setting the fabric band (12) in a heating device (20); and cutting the fabric band (12) into a webbing of defined length, wherein the multifilament yarn is formed at least from a thermoplastic polymer which is partially or completely manufactured using recycled and / or renewable raw materials and wherein the warp yarns have a yarn fineness of 750 dtex to 2000 dtex, and / or wherein the fabric band is formed with a warp yarn density of 50 to 125 warp yarns / cm.Method according to claim 1, characterized in that the multifilament yarn has a yarn fineness 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 fineness of 855 to 915 dtex with a warp thread density of 100 to 110 warp threads / cm.Method according to claim 1, characterized in that the multifilament yarn has a yarn fineness with a nominal value of 1100 dtex and a warp thread density of 77 to 101 warp threads / cm, and / or a yarn fineness of 1130 to 1210 dtex and a warp thread density of 75 to 92 warp threads / cm.Method according to claim 1, characterized in that the multifilament yarn has a yarn fineness 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 fineness of 1720 to 1840 dtex and a warp thread density of 54 to 68 warp threads / cm.Method according to one of the preceding claims, characterized in that the heat-setting is carried out at a temperature of not more than 225°C, preferably from 190°C to 220°C.Method according to one of the preceding claims, characterized in that the multifilament yarn is provided with friction-reducing equipment, preferably with an application quantity of 0.83 to 0.95 g / passmeter, calculated on a width of the fabric band with a nominal value of 47 mm.The method according to any 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.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.Belt strap (11) obtainable according to a method according to the preceding claims 1 to 8, wherein the belt strap (11) comprises warp and weft yarns, wherein at least the warp yarns 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 yarns have a yarn fineness of 750 dtex to 2000 dtex, and / or the belt strap is formed with a warp yarn density of 50 to 125 warp yarns / cm.Belt strap according to claim 9, characterized in that the warp threads have (i) a yarn fineness 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 fineness of 855 to 915 dtex with a warp thread density of 100 to 110 warp threads / cm and the breaking load of the belt strap is at least 23 kN, or (ii) a yarn fineness with a nominal value of 1100 dtex and a warp thread density of 77 to 101 warp threads / cm and / or a yarn fineness of 1130 to 1210 dtex and a warp thread density of 75 to 92 warp threads / cm and the breaking load of the belt strap is at least 25 kN, or (iii) have a yarn fineness of 1670 dtex nominal and a warp density in a range of 56 to 75 warp yarns / cm, and / or a yarn fineness of 1720 to 1840 dtex and a warp density of 54 to 68 warp yarns / cm, and the breaking load of the belt strap is at least 25 kN.

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