An elastomeric product, in particular a strength member comprising at least one first yarn coated with rubber for a vehicle tire, a method for manufacturing a rubber-coated strength member, and a vehicle tire having at least one rubber-coated strength member

Abstract

The present invention relates to an elastomeric product, particularly a strength member for a vehicle tire, comprising at least one rubber-coated first yarn, a method for producing the rubber-coated strength member, and a vehicle tire having at least one rubber-coated strength member, wherein the first yarn is a HMLS-PET yarn containing recycled PET.

Description

Technical Field

[0001] The present invention relates to an elastomeric product, in particular a strength member comprising at least one first yarn coated with rubber for a vehicle tire, a process for manufacturing such a rubber-coated strength member, and an automotive tire comprising at least one rubber-coated strength member.

Background Art

[0002] Strength members for reinforcing various elastomeric products are known. In the case of vehicle tires, it is known that they usually have various strength members among their various components, each of which is coated with a rubber mixture (which is also called a rubberization mixture). Thus, those strength members exist as rubber-coated strength members in vehicle tires.

[0003] Among those components in which fabric strength members are used, the material used for that (fabric) strength member is often polyethylene terephthalate (PET).

[0004] It is also similarly known that it is possible to use a PET having specific properties, such as that called HMLS-PET. HMLS-PET is High Modulus Low Shrinkage polyethylene terephthalate (HMLS-PET).

[0005] HMLS-PET is used, in particular, in the carcass ply of vehicle tires in order to optimize the flat spot characteristics (= reversible plastic flattening in the road surface contact area when parked) and to avoid excessive compression of the sidewall.

[0006] A further object is to solve, or at least improve, the trade-off relationship between sustainability and performance requirements that exists when selecting materials for elastomeric products such as vehicle tires.

[0007] German Patent Application Publication No. 102010017107 A1 discloses a reinforcing cord comprising at least one yarn of recycled PET. The recycled PET may in particular be derived from PET beverage bottles.

[0008] However, the use of recycled PET has limitations due to its properties. For example, recycled PET from bottles contains contaminants that impair its crystallization during its processing operations, in particular during the spinning process for obtaining industrial yarns. This deteriorates the physical properties compared to conventional PET, i.e., PET from virgin products that are not recycled PET. This is particularly evident in the case of PET where high demands are made in terms of shrinkage, deformability, and elongation, as well as strength. SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0009] Accordingly, an object of the present invention is to provide a rubber-coated strength member for an elastomeric product, particularly for a vehicle tire, wherein the strength member comprises at least one first yarn having high strength and high extensibility and at the same time enabling maximum resource conservation, maximum sustainability, and minimum environmental impact. MEANS FOR SOLVING THE PROBLEM

[0010] This object is achieved in that the first yarn is a yarn of HMLS-PET containing recycled PET.

[0011] The first yarn preferably contains 10% to 100% by weight of recycled PET.

[0012] The first yarn of HMLS-PET containing recycled PET, preferably 10% to 100% by weight of recycled PET, is also referred to as the "first yarn" in the context of the present invention.

[0013] Surprisingly, the yarn contains preferably 10% to 100% by weight of recycled PET, and at the same time, in combination with low shrinkage, has a high modulus and thus high strength, so that it was possible to provide a rubber-coated strength member containing at least one kind of PET yarn that can be classified as an HMLS-PET yarn.

[0014] The strength member of the present invention has the advantage that it is manufactured in a resource-saving and environmentally friendly manner compared to virgin PET, and nevertheless meets the high required performance for use in elastomer products, especially in the carcass ply of vehicle tires.

[0015] The numerical values of weight in percent (weight%) are based on the yarn that is not rubber-coated and not pretreated, i.e., not particularly dip-treated.

[0016] "Recycled PET" is to be understood as meaning PET obtained from used PET products such as PET bottles or other PET articles such as clothing in the context of the present invention.

[0017] The direct starting material for recycled PET is not mineral oil but PET bottles or other articles.

[0018] A preferred process for obtaining recycled PET having HMLS performance will be described in detail below.

[0019] Further advantages and features of the strength member of the present invention are also apparent from the dependent claims related to the advantageous configurations of the present invention and should not be construed as limiting. The present invention further includes combinations of features of different dependent claims, even if they are not related to each other or belong to different claim categories, provided that this is technically possible. This also applies to the individual features of the working examples described later in this specification to the extent that a person skilled in the art cannot recognize that they necessarily belong together. The present invention similarly includes combinations of features recognized as "preferred", "particularly preferred", etc., and it is possible, for example, to combine a first feature recognized as "preferred" with a further second feature recognized as "particularly preferred", unless it is clearly evident from the content or for technical reasons that this is not the case.

[0020] If the strength member contains less than 100% by weight of recycled PET, i.e., for example and specifically, if it contains 10% to less than 100% by weight of recycled PET, the remaining components are virgin PET derived from mineral oil-based (petrochemical) or renewable raw materials without undergoing any recycling process.

[0021] If the recycled PET content in the first yarn is 10% to 100% by weight, the costs and CO2 load in the production of the rubber-coated strength member and the automotive tire of the present invention can be adjusted individually.

[0022] The object underlying the present invention is particularly preferably achieved the higher the proportion of recycled PET. However, for example, even if the proportion of recycled PET is 10% by weight, it contributes to resource conservation and a reduction in CO2 load.

Brief Description of the Drawings

[0023]

Figure 1

Mode for Carrying Out the Invention

[0024] In an advantageous embodiment, the first HMLS-PET yarn contains 20 wt% to 100 wt% of recycled PET.

[0025] In an advantageous embodiment, the first HMLS-PET yarn contains 30 wt% to 100 wt% of recycled PET.

[0026] In an advantageous embodiment, the first HMLS-PET yarn contains 40 wt% to 100 wt% of recycled PET.

[0027] In an advantageous embodiment, the first HMLS-PET yarn contains 50 wt% to 100 wt% of recycled PET.

[0028] In an advantageous embodiment, the first HMLS-PET yarn contains 60 wt% to 100 wt% of recycled PET.

[0029] In an advantageous embodiment, the first HMLS-PET yarn contains 70 wt% to 100 wt% of recycled PET.

[0030] In an advantageous embodiment, the first HMLS-PET yarn contains 80 wt% to 100 wt% of recycled PET.

[0031] In an advantageous embodiment, the first HMLS-PET yarn contains 90 wt% to 100 wt% of recycled PET.

[0032] In an advantageous embodiment, the first HMLS-PET yarn contains 100 wt% of recycled PET.

[0033] Particularly preferably, the HMLS-PET yarn contains 30% to 100% by weight, more preferably 50% to 100% by weight, of recycled PET.

[0034] Recycled PET differs from virgin PET in terms of contaminants, particularly in terms of the content of isophthalic acid (IPA). These contaminants, particularly IPA, are present, for example and in particular, in PET bottles.

[0035] While virgin PET has an isophthalic acid content of 0% by weight, the IPA content in recycled PET can be up to 5% by weight.

[0036] More specifically, among the recycled PET used in the context of the present invention, it is, for example and in particular, 1.2% to 2.2% by weight.

[0037] The numerical values of weight percentages (wt%) are, in this case, based on PET, and thus, in the strength members of the present invention, on yarns that are not rubber-coated and have not been pretreated, i.e., in particular, not immersed.

[0038] In the case of a ratio of 10% by weight of recycled PET and 90% by weight of virgin mineral oil-based PET, the isophthalic acid content is thus 0.12% to 0.5% by weight, preferably 0.12% to 0.22% by weight.

[0039] Thus, the first HMLS-PET yarn preferably has an isophthalic acid (IPA) content of, for example, 0.12% to 5% by weight, preferably 0.12% to 2.2% by weight.

[0040] It should be understood that "HMLS yarn" in this case means a high modulus and low shrinkage yarn.

[0041] In this case, the yarn of the first HMLS-PET is specifically and preferably less than 8%, more preferably 4% - 8% heat shrinkage, and elongation at 45N of 0.0056% / den (percent per denier), more preferably 0.002 - 0.0056% / den, and together with these, it has a filament fineness of less than 5 den, more preferably 3 - 5 den.

[0042] These numbers are particularly suitable for determining the characteristics of the yarn of the first HMLS-PET as an HMLS yarn.

[0043] Preferably, the first yarn of the strength member of the present invention has a breaking strength of 7.0 - 9.0 g / den (grams per denier).

[0044] Preferably, the first yarn of the strength member of the present invention has an elongation at break of 10.2% - 15.5%.

[0045] The first yarn is particularly and preferably a continuous multi-yarn, and thus, preferably not a monofilament yarn and preferably not a staple fiber yarn.

[0046] Preferably, the first yarn of the strength member of the present invention contains filaments having a filament fineness of less than 5 den, which means that each filament of the yarn is preferably thinner than 5 den. More preferably, the first yarn has a filament fineness of 3 - 5 den.

[0047] Preferably, the first yarn has an elongation at a force of 45N of less than 0.0056% / den.

[0048] Tensile strength, elongation at 45 N, and elongation at break are measured by an Instron tensile tester in accordance with ASTM D885 in the context of the present invention: Instron 5564 device (clamp; C-clamp, 2714-004 (pneumatic operation), load capacity; 1 kN (1 kilonewton)), test conditions: gauge length; 250 mm, crosshead speed; 300 mm / min, pre-tension; 0.05 gf / den (grams of weight per denier), air pressure; 0.4 - 0.6 MPa, conditioning of the sample before testing: 24 ± (plus / minus) 2 °C, 55 ± 5% atmospheric humidity for 24 hours.

[0049] Preferably, the first yarn of the strength member of the present invention has a heat shrinkage of 3.2% - 5.2% at 177 °C.

[0050] The heat shrinkage of the yarn is measured by means of the heat shrinkage method in accordance with ASTM D885 in the context of the present invention. The test conditions are as follows: temperature 177 °C, load 0.05 g / den, time 10 minutes.

[0051] Preferably, the first HMLS-PET yarn has a crystallization level of 45% - 53.5%.

[0052] The crystallization level is measured as follows in accordance with ASTM D1505: First, the density of the yarn is examined using a density gradient column. Then, the crystallization level is calculated by interpolation using the literature values for the density of 100% amorphous PET and 100% crystalline PET (described later). The density of 100% amorphous PET is 1.333 g / cm 3 and, in contrast, the density of 100% crystalline PET is 1.455 g / cm 3 is.

[0053] With such a crystallization level, the yarn, and thus the strength member of the present invention, can be manufactured and, at the same time, has the required performance in terms of elongation and shrinkage characteristics, which are highly demanded particularly when used in the carcass ply of vehicle tires.

[0054] Preferably, the yarn of the first HMLS-PET has a fineness of 300 to 4000 denier (den), preferably 300 to 3100 den, more preferably 300 to 2000 den, and most preferably 900 to 2000 den.

[0055] In the first embodiment, the first yarn is twisted and further processed as follows. In this embodiment, the strength member of the present invention includes a twisted and rubber-coated yarn.

[0056] In a further advantageous embodiment, it is also possible to twist one or more yarns to form a cord. In each case, the first yarn is preferably an HMLS-PET yarn containing 10% to 100% by weight of recycled PET, as described in the present invention.

[0057] In a particularly preferred embodiment, at least one additional (second) yarn is also preferably an HMLS-PET yarn containing 10% to 100% by weight of recycled PET, so that in this embodiment, at least the two described HMLS-PET yarns are twisted together to form a single cord.

[0058] In an advantageous embodiment of the present invention, the first yarn is twisted into the form of a "×2 cord", where the cord has a twist factor of 150 to 250, preferably 170 to 230, and a breaking force of at least 6.3 g / den, preferably 6.3 to 10 g / den, and an elongation at 45 N of less than 0.0056% / den, preferably 0.0005% to 0.0040% / den, and a heat shrinkage of less than 3%, preferably 1% to 3%, more preferably 1.5% to 2.5%.

[0059] The expression "×2 cord" means that two yarns are twisted together.

[0060] In the embodiments described, the first yarn (as described in the present invention, an HMLS-PET yarn containing recycled PET) is preferably twisted together with a second, additional HMLS-PET yarn containing recycled PET to provide a single cord.

[0061] The heat shrinkage of the cord is measured in the context of the present invention by means of a heat shrinkage method at 180 °C according to ASTM D885. The test conditions are as follows: temperature 180 °C, load 0.05 g / den, time 10 minutes.

[0062] In a further preferred embodiment, alternatively, at least one of the additional yarns is a different type of yarn, so that the strength member of the present invention is preferably a hybrid cord comprising an HMLS-PET yarn containing 10 wt% to 100 wt% recycled PET and at least one additional yarn. The at least one additional yarn is, in this case, preferably a non-metallic material (consisting of a non-metallic material). The non-metallic material is preferably selected from the group comprising: polyamide (PA) and / or aramid and / or polyether ketone (PEK) and / or polyketone (POK) and / or polyethylene naphthalate (PEN) and / or rayon and / or viscose and / or natural fiber and / or glass fiber.

[0063] The described yarn and / or the described cord is, in a preferred embodiment, woven to form a textile ply, which is then further processed by adhesion using a rubber coating mixture and activation of the rubber coating.

[0064] The present invention further provides a strength member ply composed of a plurality of rubber-coated strength members of the present invention.

[0065] The present invention further provides a vehicle tire comprising at least one rubber-coated strength member of the present invention.

[0066] In an advantageous embodiment of the present invention, the vehicle tire includes, within the carcass ply, a plurality of the rubber-coated strength members of the present invention.

[0067] The carcass ply preferably includes a carcass ply and / or a belt ply and / or a bandage ply and / or a bead reinforcement, more preferably at least a carcass ply.

[0068] Therefore, the vehicle tire of the present invention may further include the strength member of the present invention in one or more components, preferably at least in the carcass ply.

[0069] In an advantageous embodiment of the present invention, the carcass ply is at least a carcass ply, where the carcass ply is wound around the bead once (1-ply construction) or twice (2-ply construction) in a folded state, and in this case, the ends of these plies are located between the ends of the core and the belt.

[0070] In this way, the vehicle tire can meet its required load-bearing capacity (taking into account each load index).

[0071] In an advantageous development of this embodiment, in addition to the one or two carcass plies wound around the bead, a further carcass ply including the strength member of the present invention is arranged in the sidewall above or below the bead.

[0072] Thereby, the vehicle tire is further improved in terms of load-bearing capacity.

[0073] The following describes a particularly preferred process by which it is possible to obtain a first yarn of a rubber-coated strength member. The yarns are manufactured as continuous multi-yarns as described above. The processing steps described in detail are carried out using equipment known to those skilled in the art, unless otherwise stated. a) Providing PET chips comprising 100% by weight of recycled PET from PET bottles or other PET products, and optionally virgin PET chips; b) Pre-crystallizing, crystallizing, and solid-state polymerizing (SSP) the PET chips from step a) to obtain high-viscosity PET chips having an intrinsic viscosity of 0.85 to 1.15 dl / g (deciliters per gram); c) A drying step, optionally mixing the recycled PET chips with virgin PET chips to obtain PET chips containing chips from recycled PET from 10% to 100% by weight, melting and extruding the PET chips for spinning the yarn, and subsequently spinning the yarn by means of a spinneret comprising a heater with a buffer zone, and stepwise cooling the undrawn yarn (where the moisture content of the chips after drying is less than 30 ppm, the temperature of the heater under the spinneret is 280 to 350 °C, and the length of the buffer zone under the heater during the stepwise cooling is 20 to 100 mm); d) After the stepwise cooling in step c), oiling, drawing, heat setting, and winding to obtain HMLS-PET yarns.

[0074] The fact that it is possible to obtain recycled PET in the form of chips is known to those skilled in the art. These chips can also be called "granules".

[0075] "PET chips comprising 100% by weight of recycled PET from PET bottles or other PET products" are also referred to herein as "chips of recycled PET".

[0076] The inherent viscosity is measured by means of an Ubbelohde capillary viscometer in accordance with ASTM D4603 in the context of the present invention.

[0077] When the yarn contains less than 100% by weight of recycled PET, i.e., in particular when it contains from 10% to less than 100% by weight of recycled PET, the remaining components are virgin PET derived from mineral oil-based (petrochemical) or renewable raw materials without undergoing any recycling process.

[0078] In this case, in an additional processing step (referred to above as "optionally mixing step"), the chips of recycled PET and the chips of virgin PET are mixed with each other before the spinning process. This mixing is preferably carried out in a single-screw conveying system after the drying step.

[0079] If 100% by weight of recycled PET is used, an additional mixing step is not required and the chips are directly dried and extruded.

[0080] Impurities present in recycled PET, such as monomers replacing p-terephthalic acid, such as IPA, weaken the ability of PET to crystallize during the spinning process. This complicates the spinning and drawing for forming the yarn and deteriorates their properties compared to the yarns of virgin PET.

[0081] In pre-crystallization, crystallization, and solid state polymerization (SSP) in step b), further polymerization is achieved, whereby the ratio of shorter polymer molecules decreases, whereby the molecular chains grow. As a result, the inherent viscosity increases. Thereby, the drawability of the material is improved, and at the same time the tensile rigidity and modulus (rigidity) of the yarn are similarly improved.

[0082] Preliminary crystallization and crystallization, In step c), the temperature of the heater under the spinneret is 280 - 350 °C and The length of the buffer zone under the heater during stepwise cooling shall be 20 to 100 mm and By combining these, in the spinning process, a high spinning speed and a high drawing speed can be selected, and it becomes possible to adjust the crystallization rate

[0083] Furthermore, the frequency of filament and yarn breakage decreases, and as a result, a yarn having high tensile rigidity and high modulus can be obtained

[0084] Solid state polymerization (SSP) is a process in which crude PET chips as raw materials are put into a reactor, heated and polymerized. By this, the molecular chain length is extended and the intrinsic viscosity increases. The intrinsic viscosity of recycled PET chips is 0.55 to 0.75 dl / g

[0085] Solid state polymerization is also called solid state condensation because condensation is brought about by removing water

[0086] It is more preferable to process those crude raw material chips, which still have a relatively low viscosity, as follows

[0087] The crude PET chips as raw materials are preferably pre-crystallized at a temperature of 150 to 180 °C for 0.5 to 1.5 hours, then crystallized at a temperature of 200 to 230 °C for 4 to 6 hours, and finally reacted in an SSP reactor with a wall temperature of 200 to 220 °C for 30 to 35 hours

[0088] The entire system of the apparatus is operated in a nitrogen atmosphere, and at that time, the oxygen content of the nitrogen is maintained at 30 to 70 ppm, and the dew point is preferably less than -70 °C (less than minus 70 °C)

[0089] Here, the intrinsic viscosity of the crude PET chips as raw materials increases to 0.85 to 1.15 dl / g, and high-viscosity chips are obtained

[0090] In step c), it is preferable to dry under nitrogen. In that case, the drying temperature is preferably 120 to 160 °C, and the drying time is preferably longer than 8 hours. Thereby, the moisture content of the high-viscosity chip is reduced to less than 30 ppm.

[0091] In step c), it is preferable to carry out melting and extrusion processing of the high-viscosity PET chip in the form of melt extrusion in a screw extruder. In this case, the temperature in the feed zone of the screw extruder is 300 to 330 °C, the temperature in the compression zone is 290 to 320 °C, and the temperature in the metering zone (discharge zone) is 280 to 310 °C, and the pressure at the extruder head is 14 to 18 MPa (megapascal). Thereby, a melt is obtained.

[0092] This melt extrusion further improves the melt viscosity and fluidity of the high-viscosity chip, and furthermore reduces the adverse effects caused by including IPA, thereby further improving the drawability.

[0093] When the high-viscosity recycled PET chips are premixed with virgin PET chips, the extrusion step further improves the homogeneity of the mixture of recycled PET and virgin PET.

[0094] (In step c) Spinning is preferably carried out by means of a spinning jet method such that the ratio of the length to the diameter (L / D) of the holes of the spinneret in an advantageous embodiment is 1.2 to 3.0.

[0095] In an advantageous embodiment, the spinneret contains 180 to 480 holes, and a yarn of 1000 to 1500 denier is obtained.

[0096] In a further advantageous embodiment, it is possible to obtain yarns of 300 to 4000 denier (den), preferably 300 to 3100 den, more preferably 300 to 2000 den, even more preferably 900 to 2000 den, for example, in particular 500 denier, 2000 denier, or 4000 denier. When selecting a fineness higher than 1500 denier, the number of holes in the spinneret can exceed 480.

[0097] It is preferred if a yarn having filaments with a filament fineness of less than 5 denier (den) is obtained. It is more preferred if a yarn having filaments with a filament fineness of 3 to 5 den is obtained.

[0098] The stepwise cooling in step c) aims to solidify the melt of the undrawn yarn.

[0099] Preferably, the stepwise cooling in step c) includes an annular quenching system downstream of the buffer zone. In this case, the cooling air is blown from the outer ring to the inner ring, and the blowing pressure in that case is 15 to 50 Pa, and the blowing temperature is 22 to 65 °C.

[0100] Thereby, the fusion of the undrawn yarn is prevented, and the stretching process in the downstream step d) is simplified, that is, it does not become complicated. By setting the blowing pressure and temperature of the blown air to suitable parameters, excessive rapid cooling and excessive slow cooling can be avoided, thereby preventing the fusion of the undrawn yarn and the deterioration of physical properties.

[0101] If the undrawn yarn is cooled too rapidly, in particular, stretching in the spinning operation becomes more difficult.

[0102] If the undrawn yarn is cooled too slowly, there are specific risks of increased fusion and deterioration in physical properties.

[0103] For the reasons stated above, it is particularly advantageous if, after melt spinning, the undrawn yarn is reheated and cooled step by step by means of an annular quenching system downstream of the buffer zone and then cooled using cooling air.

[0104] Oiling in step d) has the advantage that the cohesion of the undrawn yarn is increased and the frictional force and electrostatic charge are reduced. This likewise facilitates the downstream drawing process and reduces the breakage frequency of the filaments and yarns. Furthermore, this is also advantageous for downstream processing steps, since the yarn is made slippery as a result of the oiling, so that a rubber-coated strength member can be obtained, i.e., in particular, a ply of the fabric can be obtained in twisting and weaving.

[0105] Preferably, the oil is used in the form of an emulsion, and the exhaustion rate of the oil is preferably 0.3% to 0.9% by weight, based on the yarn.

[0106] The drawing in step d) is preferably carried out by means of a godet roll configuration, in which case a first pair of godet rolls (GR1) (speed 2700 to 3200 m / min, temperature 60 to 80 °C), a second pair of godet rolls (GR2) (speed 3800 to 5000 m / min, temperature 70 to 90 °C), and a third pair of godet rolls (GR3) (speed 5800 to 6200 m / min, temperature 210 to 260 °C) are operated, and the draw ratio is preferably 1.81% to 2.30%.

[0107] By doing so, it becomes possible to achieve the optimum properties of the produced yarn, such as optimized breaking strength and elongation at break, as well as optimized heat shrinkage and modulus.

[0108] Preferably, in this case, the thermosetting carried out after stretching is carried out by means of a fourth godet roll pair (GR4) (speed 5800 - 6200 m / min, temperature 210 - 260 °C), a fifth godet roll pair (GR5) downstream (speed 5600 - 6200 m / min, temperature 210 - 260 °C), and a sixth godet roll pair (GR6) downstream (speed 5450 - 6000 m / min, temperature 100 - 150 °C), where the relaxation rate is 2.5% - 6.0%.

[0109] By doing so, it becomes possible to achieve optimal crystallization, a stable microstructure, optimal breaking strength, and optimal modulus, as well as reduction of thermal shrinkage. In this way, the yarn is optimally prepared for the downstream winding process and thermosetting.

[0110] The winding in step d) is preferably carried out at a winding speed of 5450 - 5950 m / min.

[0111] By the processing steps a) - d) described, a yarn is obtained, which has a breaking strength of 7.5 - 9.0 g / d, an elongation at break of 10.2% - 15.5%, a thermal shrinkage of 3.2% - 5.2%, a crystallization level of 45% - 53.5%, and an IPA content of 0.12 wt% - 5 wt%, particularly 0.12 wt% - 2.2 wt%.

[0112] In addition, it is also possible to obtain a yarn having a fineness of 300 - 4000 denier.

[0113] The HMLS - PET yarn thus obtained, containing 10 wt% - 100 wt% recycled PET, is further processed, particularly and preferably, for the purpose of obtaining the rubber - coated strength member of the present invention, by at least the following processing steps: e) Twisting step; f) Optionally, weaving step; g) Step of modifying adhesiveness using dipping treatment; h) Step of rubber - coating using a rubber - coating mixture.

[0114] In an advantageous embodiment of the invention, the yarn is first twisted on its own and then twisted using a similarly twisted yarn to form a cord.

[0115] Each of the yarns used in the cord may preferably be formed from filaments twisted in the S and Z directions. Thus, for example, it is possible to twist an HMLS-PET yarn containing recycled PET in the S or Z direction.

[0116] The twisted yarn is then twisted in the S or Z direction to form a reinforcing cord. It is advantageous if all the yarns of the reinforcing cord have the same direction of twist, i.e., they are twisted either in the S or Z direction. In this advantageous variant, the reinforcing cord has a direction of twist opposite to that of the yarns. For example, an HMLS-PET yarn containing recycled PET, twisted in the S direction, may finally be further twisted in the Z direction using a further HMLS-PET yarn (containing recycled PET) twisted in the S direction to form a reinforcing cord.

[0117] Alternatively, a corresponding hybrid cord is included, where, for example, it is also conceivable that an HMLS-PET yarn containing recycled PET, twisted in the S direction, is finally twisted together with a further yarn. Explanatory and suitable materials for the further yarn have been described above.

[0118] In an advantageous embodiment of the invention, two yarns are twisted on a direct cabling machine to form a cord from the two yarns (a "×2 cord").

[0119] The twist number of the yarn and the cord (tpm, "turns per meter") is preferably 100 - 500 tpm in each case.

[0120] The cord containing the first yarn preferably has a twist factor TF of 150 to 250. The twist factor is calculated according to Equation I): I) TF = N * (K / 9000)^0.5 [where N is the number of twists (unit: tpm), K is the fineness of the cord, and ^0.5 is considered to represent the square root (of the expression in parentheses), that is, TF = number of twists (unit: tpm) * × [cord fineness (unit: denier) / 9000]^0.5 (to the power of 0.5).]

[0121] In weaving (step f), the following should preferably be noted.

[0122] In the arrangement of the yarn on the package creel, the distortion applied to each yarn package is controlled by roller bearings and rubber belts to ensure uniform distortion. During the weaving process, the yarn is introduced through a reed adjusted according to the specification and woven on an air jet loom. Then, the cord is woven to obtain a greige cloth with a preset width, and the weft yarns are, in particular, yarns having an elastic core of, for example, PET or nylon, wound with, for example, cotton.

[0123] The greige cloth obtained in step f) is then further processed by means of the dipping treatment in step g). As a result, the strength member, in particular the yarn or cord, is given ideal physical properties and an optimized adhesion ability to the rubber coating mixture to be applied later.

[0124] More specifically, the dipping treatment may include a preliminary dipping treatment and an RFL (resorcinol-formaldehyde-latex) dipping treatment or an RFL-free alternative treatment known to those skilled in the art (which is environmentally and health-friendly and is described, for example, in German Patent Application Publication No. 102014211362A1 or International Publication Pamphlet No. 2019015792A1).

[0125] Therefore, the modification of adhesion by means of the dipping treatment in step g) may particularly include a one-bath method or a two-bath method (preliminary dipping treatment and dipping treatment) known to those skilled in the art.

[0126] During the dipping method, devices and conditions known to those skilled in the art, such as a dipping treatment solution tank, a tension zone, and an oven, are used skillfully. Here, the fabric or cord is stretched by 0% to 8%, particularly 0% to 3% (which depends on whether the weaving in step f) is carried out).

[0127] The subsequent rubber coating in step h) is carried out by means of a rubber coating mixture and a device known to those skilled in the art in a method known to those skilled in the art. This may include drying at a high temperature exceeding 100°C, particularly before the rubber coating.

[0128] The rubber coating mixture may be various suitable rubber coating mixtures known to those skilled in the art for covering the strength member, particularly the fabric strength member.

[0129] Preferably, at least one diene rubber is included in the rubber coating mixture.

[0130] A diene rubber is a rubber formed by polymerizing or copolymerizing a diene and / or a cycloalkene, and for this purpose, it has a C=C double bond in either the main chain or the side group.

[0131] In advantageous embodiments, the diene rubber is selected from the group consisting of natural polyisoprene (NR), synthetic polyisoprene (IR), butadiene rubber (BR), solution-polymerized styrene-butadiene rubber (SSBR), and emulsion-polymerized styrene-butadiene rubber (ESBR).

[0132] In advantageous embodiments, the rubber coating mixture contains at least one carbon black as a nonpolar filler.

[0133] The carbon black is preferably used in an amount of 0.1 to 100 phr, more preferably 40 to 100 phr, and most preferably 40 to 80 phr in the rubber coating mixture. As a result, it is particularly preferred if at least one carbon black in an amount of 57 to 67 phr is used in the rubber mixture. By doing so, particularly good mixture performance regarding tear performance is achieved.

[0134] The present invention further provides the above-described process, which includes at least steps a) to h). Preferably, the strength member of the present invention is manufactured by this method. Accordingly, the present invention further provides a strength member obtained by means of the above-described process. Note that this application relates to the invention described in the claims, but may also include the following as other aspects. 1. A rubber-coated strength member for an elastomer product, particularly for a vehicle tire, wherein the strength member includes at least one first yarn, and the first yarn is a yarn of HMLS-PET containing recycled PET. 2. The rubber-coated strength member according to 1 above, wherein the first yarn of HMLS-PET contains 10% to 100% by weight, preferably 30% to 100% by weight, more preferably 50% to 100% by weight of recycled PET. 3. The rubber-coated strength member according to 1 or 2 above, wherein the first yarn of HMLS-PET contains 0.12% to 5% by weight, particularly 0.12% to 2.2% by weight of isophthalic acid (IPA). 4. The rubber-coated strength member according to any one of 1 to 3 above, wherein the first yarn of HMLS-PET has a crystallization level of 45% to 53.5%. 5. The rubber-coated strength member according to any one of 1 to 4 above, wherein the first yarn of HMLS-PET has a fineness of 300 to 4000 denier (den), preferably 300 to 3100 den, more preferably 300 to 2000 den, and most preferably 900 to 2000 den. 6. The rubber-coated strength member according to any one of 1 to 5 above, wherein when the filament fineness of the first yarn of HMLS-PET is less than 5 den, it has a heat shrinkage of less than 8% and an elongation at 45 N of less than 0.0056% / den. 7. The rubber-coated strength member according to any one of 1 to 6 above, wherein the first yarn is twisted into "×2 cord", and the cord has a twist coefficient of 150 to 250 and a breaking force of at least 6.3 g / den, an elongation at 45 N of less than 0.0056% / den, and a heat shrinkage of less than 3%. 8. A process for manufacturing the rubber-coated strength member according to 1 above, including at least the following a) steps of providing PET chips containing 100% by weight of recycled PET from PET bottles or other PET products, and optionally chips of virgin PET; b) steps of pre - crystallizing, crystallizing, and solid - state polymerizing the PET from step a) to obtain high - viscosity PET chips having an intrinsic viscosity of 0.85 - 1.15 dl / g; c) a drying step, optionally mixing the chips of the recycled PET with chips of virgin PET to obtain PET chips containing chips from recycled PET from 10% to 100% by weight, melting and extruding the PET chips using the high - viscosity PET chips from step b) for spinning yarn, and then spinning the yarn by means of a spinneret including a heater having a buffer zone, and step of gradually cooling the undrawn yarn, wherein the moisture content of the chips after drying is less than 30 ppm, the temperature of the heater under the spinneret is 280 - 350 °C, and the length of the buffer zone under the heater during the step of gradual cooling is 20 - 100 mm; d) steps of oiling, stretching, heat - curing, and winding after the step of gradual cooling in step c) to obtain HMLS - PET yarn; e) a twisting step; f) optionally, a weaving step; g) steps of modifying the adhesiveness using dipping treatment; h) steps of rubber - coating using a rubber - coating mixture; The process includes the processing steps as above. 9. A vehicle tire, comprising at least one rubber - coated strength member according to any one of items 1 - 7 above. 10. The vehicle tire according to item 9 above, characterized in that it comprises a plurality of rubber - coated strength members according to any one of items 1 - 7 above in the form of a strength member ply. 11. The vehicle tire according to item 10 above, characterized in that the strength member ply is at least a carcass ply and / or a belt bandage and / or a belt ply and / or a bead reinforcement. 12. The strength member ply is at least the carcass ply, and the carcass ply is wound around the bead once (1-ply construction) or twice (2-ply construction) in a folded state, and the end of the ply is located between the ends of the core and the belt. The vehicle tire according to 11 above, characterized in that.

[0135] Hereinafter, the present invention will be described in detail with reference to several working examples. In this regard, first, Table 1 shows an overview of the yarns used as examples and their manufacturing parameters in the strength member of the present invention.

[0136] In addition to the specifically specified parameters, the above-mentioned overview can be applied here. More specifically, in all of Examples E1 to E6, a process according to steps a) to d) was carried out, including the solid-phase polymerization mentioned above. The crude PET chips were pre-crystallized at a temperature of 150 to 180 °C for 0.5 to 1.5 hours, then crystallized at a temperature of 200 to 230 °C for 4 to 6 hours, and finally reacted in an SSP reactor with a wall temperature of 200 to 220 °C for 30 to 35 hours.

[0137] The entire system of the apparatus was operated in a nitrogen atmosphere. At that time, the oxygen content of the nitrogen was maintained at 1,30 to 70 ppm, and its dew point was preferably less than -70 °C (less than minus 70 °C).

[0138] [Table 1]

[0139] [Table 2]

[0140] In Figure 1, Examples E1 - E6 are plotted in the form of a bar graph against the ratio of recycled PET, where the height of the bar represents the CO2 emissions (CO2 (kg) / product (kg)). The numbers are based on subtracting the contributions in the production of monomers such as monoethylene glycol (MEG) and PTA (purified terephthalic acid) from PET chip production. The processes starting from yarn production and subsequent processes are considered independent of the PET raw material with respect to CO2 emissions.

[0141] The left - hand bar graph shows the CO2 emissions of virgin PET, while the two right - hand bar graphs show the CO2 emissions of bio - based PET (about 30 wt% of its raw material is derived from renewable raw materials as its ethylene glycol monomer is obtained from corn) and HIPS (high impact polystyrene).

[0142] As is clear from Figure 1, using PET made from 100 wt% recycled PET achieves the lowest CO2 emissions. The CO2 balance of recycled products only starts, for example, after being used as a PET bottle.

[0143] The bar graphs of "virgin PET" and "bio - PET" do not include the CO2 emissions from monomers produced from other raw materials. This means that these numerical values substantially include the polycondensation into PET chips.

[0144] In the case of 100% recycled PET, the numerical value substantially includes the grinding and remelting to obtain PET chips.

[0145] The numerical values for those in between (i.e., 10% - 90% PET) are calculated by proportional distribution from the numerical values of "virgin PET" and "100% recycled PET".

[0146] In addition, further experiments were carried out, in which 100% by weight of recycled PET (for example, E1) was used, and in each case, different processing steps were applied.

[0147] The procedure in Comparative Experiment V2 is the same as that for E1, except that the entire process of solid-state polymerization was omitted.

[0148] The procedure in Comparative Experiment V3 is the same as that for E1, except that solid-state polymerization was carried out without pre-crystallization and crystallization steps.

[0149] The procedure in Comparative Experiment V4 is the same as that for E1, except that the undrawn yarn after the spinning process was directly cooled by means of cooling air without reheating using a buffer zone (see Step c).

[0150] The procedure in Comparative Experiment V5 is the same as that for E3, except that the undrawn yarn after the spinning process was directly cooled by means of cooling air without reheating using a buffer zone (see Step c).

[0151] Table 2 shows the influence of various different types of processes on the physical properties of each of those yarns.

[0152] Those properties were measured by the means of the method described above.

[0153] A further criterion used was the level of filament breakage in the yarn manufacturing process. For each bobbin (9 kg, length 62 km, 1300 den), it was stipulated that the number of filament breaks must be less than 10 in order to be classified as qualified (qualified = Q). Otherwise, the sample was evaluated as inadequate (inadequate = NQ).

[0154]

Table 3

[0155] The data in Table 2 indicate that the yarns produced by the process including steps a) to d), including solid-phase polymerization, spinning, cooling process, and stretching process, have properties comparable to those of the yarns produced by the conventional method, such as breaking strength and elongation at break. Therefore, by using the yarns according to Examples E1 to E6, it is possible to efficiently manufacture vehicle tires containing the rubber-coated strength member of the present invention and its rubber-coated strength member, particularly in the form of a strength member ply, with a low defect rate (less than 4%), and at the same time, due to its high-quality properties, the corresponding requirements during use are satisfied.

[0156] Compared with V2, the solid-phase polymerization in E1 achieves growth of molecular chains and reduction of contaminants present in recycled PET, such as monomers replacing p-terephthalic acid, such as IPA.

[0157] Compared with V3, the pre-crystallization and crystallization as part of the solid-phase polymerization process in E1 achieve improved quality and processability of high-viscosity chips, and suppress adverse effects in the SSP reactor, such as cementation and agglomeration. When these adverse effects occur, irregular discharge of the SSP reactor is required, and the dispersion of the intrinsic viscosity of the high-viscosity chips becomes high. Furthermore, this results in further unfavorable consequences, such as non-uniform melting points, non-uniform melting characteristics, and non-uniform crystallization rates of the yarns. This increases the frequency of filament and yarn breakage and generally makes yarn production significantly difficult.

[0158] When pre-crystallization and crystallization are carried out as part of the solid-phase polymerization process, the homogeneity of the viscosity, melting point, and crystallization rate of the high-viscosity chips can be effectively controlled.

[0159] When the SSP process is not carried out, the breaking strength of the produced yarn does not meet the requirements, the frequency of filament and yarn breakage increases, and the production efficiency decreases.

[0160] Comparative Example V4 shows that when reheating after spinning and the buffer zone are omitted, the cooling of the undrawn yarn is too fast, resulting in premature hardening and crystallization, thus reducing production efficiency and physical properties.

[0161] Comparative Example V5 shows that when pre-crystallization and crystallization are omitted in the SSP process and reheating after spinning and the buffer zone are also omitted, the homogeneity of the high-viscosity chip decreases, the crystallization rate in spinning increases, the drawability deteriorates, and the crystallization level of the final yarn decreases.

[0162] Therefore, in order to slow down the crystallization rate and increase the crystallization level, pre-crystallization and crystallization should be combined with reheating and the buffer zone as described above.

[0163] Using the yarns of Examples E1 to E6 and Comparative Examples V2 to V5 listed above, cords were produced by twisting two yarns, and these cords were woven and subjected to dipping treatment to obtain dipped fabrics.

[0164] The twisting was carried out by directly twisting two yarns on a twisting machine to produce one cord from two yarns (×1×2 cord).

[0165] Those yarns were twisted in the S direction, while the cord was twisted in the Z direction.

[0166] In the weaving, the following conditions were observed.

[0167] In the arrangement of the yarns on the package creel, the distortion applied to the packages of the respective yarns was controlled by roller bearings and rubber belts to ensure uniform distortion. During the weaving process, the yarns were introduced through reeds adjusted according to the specifications and woven on an air jet loom. Then, the cords were woven to form a greige fabric with a preset width, and the weft yarns were 22.2 tex core-core spun yarns (cores composed of nylon monofilaments and covered with cotton staple fibers).

[0168] Next, the greige fabric thus obtained was further processed by means of a dipping treatment. In this case, a two-bath dipping treatment was adopted. An epoxy compound (trade name: Grilbond® G1701, manufactured by EMS-GRIL TECH) and an isocyanate compound (trade name: Grilbond® IL-6 50%F, manufactured by EMS-GRIL TECH) were prepared in the first bath, and the yarns were immersed therein, thereby activating their superficial filaments.

[0169] In the second bath, resorcinol formaldehyde latex (a resin obtained by pre-condensing resorcinol and formaldehyde in the form of an aqueous dispersion and mixed with formaldehyde, especially latex) was prepared, and the fabric activated by the means of the first bath was immersed therein. During the dipping process, devices and conditions known to those skilled in the art, such as a dipping treatment solution tank, a tension zone, and an oven, were skillfully used.

[0170] In addition, heat stretching was carried out to set the net stretching to 0% to 1%.

[0171] Regarding the cords thus obtained, their properties were examined and the results were listed in Table 3.

[0172] The notation "1500 / 2" should be read as 1500 den / 2, meaning that two yarns each having a fineness of 1500 den were twisted to form a cord. The same applies to the notation "1000 / 2".

[0173] The number of twists per meter (tpm) in Table 3 is related to each cord.

[0174] The residual strength was measured by means of a Goodrich fatigue test under the following conditions: 1800 rpm (revolutions per minute), 24 hours, 20% compression, 6.5% strain, room temperature.

[0175] [Table 4]

[0176] As is also clear from Table 3, according to Examples E1 to E6, it was possible to produce cords having properties that meet the requirements for use in the rubber-coated strength members of the present invention, particularly for vehicle tires. In contrast, Comparative Examples V2 to V5 showed poorer properties and were therefore unsuitable. In particular, the significant damage to the filaments in high-speed spinning means that the fatigue resistance of the cords produced in this way is significantly adversely affected. As is clear from Comparative Example V2, its sample broke before the fatigue test was completed.

[0177] Therefore, as seen in Examples E1 to E6, it has become possible to obtain the rubber-coated strength members of the present invention for elastomeric products, particularly for vehicle tires, which are produced in a particularly resource-saving and environmentally friendly manner and at the same time have good physical properties such as to meet the requirements in the driving operation of vehicle tires. At the same time, the vehicle tires of the present invention include at least a rubber-coated strength member in the form of a carcass ply, and particularly a plurality of rubber-coated strength members in the corresponding strength member plies forming the carcass ply.

[0178] An exemplary composition of the rubber coating mixture of the rubber-coated strength member of the present invention is shown in Table 4.

[0179] [Table 5]

Claims

1. A rubber-coated strength member for an elastomer product, wherein the strength member comprises at least one first yarn, the first yarn is a yarn of HM-LS-PET containing recycled PET, the first yarn is twisted into a "×2 cord", the cord has a twist coefficient of 150 to 250 and a breaking force of at least 6.3 g / den, an elongation at 45 N of less than 0.0056% / den, and a heat shrinkage of less than 3%, and the first yarn of HM-LS-PET has a crystallization level of 45% to 53.5%. A rubber-coated strength member characterized by that.

2. The rubber-coated strength member according to claim 1, wherein the first yarn of HM-LS-PET contains 10% to 100% by weight of recycled PET.

3. The rubber-coated strength member according to claim 1 or 2, wherein the first yarn of HM-LS-PET contains 0.12% to 5% by weight of isophthalic acid (IPA).

4. The rubber-coated strength member according to any one of claims 1 to 3, wherein the first yarn of HM-LS-PET has a fineness of 300 to 4000 denier (den).

5. The rubber-coated strength member according to any one of claims 1 to 4, wherein the first yarn of HM-LS-PET has a filament fineness of less than 5 den, and a heat shrinkage of less than 8% and an elongation at 45 N of less than 0.0056% / den.

6. A process for manufacturing the rubber-coated strength member according to claim 1, comprising at least the following, a) a step of providing PET chips containing 100% by weight of recycled PET from PET bottles or other PET products; b) subjecting the PET obtained in step a) to pre-crystallization, crystallization, and solid-phase polymerization to obtain a high-viscosity PET chip having an intrinsic viscosity of 0.85 to 1.15 dl / g, wherein the pre-crystallization is carried out at a temperature of 150 to 180°C for 0.5 to 1.5 hours, and the crystallization is carried out at a temperature of 200 to 230°C for 4 to 6 hours; c) a drying step, using the high-viscosity PET chip obtained in step b), melting and extruding the PET chip for spinning yarn, and then spinning the yarn by means of a spinneret including a heater having a buffer zone, and a step of gradually cooling the undrawn yarn, wherein the moisture content of the chip after drying is less than 30 ppm, the temperature of the heater under the spinneret is 280 to 350°C, and the length of the buffer zone under the heater during the stepwise cooling is 20 to 100 mm; d) after the stepwise cooling in step c), oiling, drawing, heat setting, and winding to obtain an HM-LS-PET yarn; e) a twisting step; g) a step of modifying the adhesiveness using a dipping treatment; h) a step of rubber coating using a rubber coating mixture; A process comprising the processing steps.

7. The process according to claim 6, characterized in that step a) further comprises a step of providing chips of virgin PET.

8. The process according to claim 6 or 7, characterized in that step c) further comprises a step of mixing the recycled PET chips with virgin PET chips to obtain PET chips containing chips from recycled PET of 10% to less than 100% by weight.

9. The following: f) a weaving step; The process according to any one of claims 6 to 8, further comprising the following:

10. In step b), the solid-phase polymerization is carried out for 30 to 35 hours in a solid-phase polymerization reactor having a wall temperature of 200 to 220°C, the process according to any one of claims 6 to 9.

11. A vehicle tire comprising at least one rubber-coated strength member according to any one of claims 1 to 5.

12. The vehicle tire according to claim 11, characterized in that it comprises a plurality of rubber-coated strength members according to any one of claims 1 to 5 in the form of a strength member ply.

13. The vehicle tire according to claim 12, characterized in that the strength member ply is at least a carcass ply and / or a belt bandage and / or a belt ply and / or a bead reinforcement.

14. The vehicle tire according to claim 13, characterized in that the strength member ply is at least the carcass ply, and the carcass ply is wound once (1-ply configuration) or twice (2-ply configuration) around the bead in a folded state, and the end of the ply is located between the ends of the core and the belt.

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