Rubberized reinforcing member, method for producing the same, and vehicle tire comprising the same

Abstract

The present invention relates to a rubberized reinforcing member for elastomeric products, in particular vehicle tires, wherein the reinforcing member comprises at least one first yarn; to a method for producing the rubberized reinforcing member; and to a motor vehicle tire comprising at least one rubberized reinforcing member. According to the invention, the first yarn is a HMLS-PET yarn comprising recycled PET.

Description

Technical Field

[0001] The present invention relates to: a rubberized reinforcing member for elastomer products, particularly vehicle tires, wherein the reinforcing member comprises at least one first yarn; a method for producing the rubberized reinforcing member; and a motor vehicle tire comprising at least one rubberized reinforcing member. Background Technology

[0002] Reinforcing members used to strengthen various elastomer products are well known. Regarding vehicle tires, it is known that they typically have various reinforcing members in various components, each of which is surrounded by a rubber compound (also called a rubberized compound). Therefore, reinforcing members exist in vehicle tires as rubberized reinforcing members.

[0003] In those components that use fabric reinforcement members, the material used for the (fabric) reinforcement members is typically polyethylene terephthalate (PET).

[0004] It is also known that PET with specific properties can be used, such as the so-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 to optimize flat spot characteristics (reversible plastic flattening in the contact area with the ground when parked) and avoid extensive sidewall shrinkage.

[0006] Another objective is to address, or at least improve, the trade-off between sustainability and performance requirements in the selection of materials for elastomer products (such as vehicle tires).

[0007] DE 102010017107 A1 discloses reinforced cords comprising yarns of at least one type of recycled PET. The recycled PET may be derived, in particular, from PET beverage bottles.

[0008] However, the use of recycled PET is limited due to its inherent characteristics. For example, recycled PET from bottles contains additives that impair crystallization during processing operations, particularly during the spinning process to obtain industrial yarns. This deteriorates physical properties compared to conventional PET (i.e., PET from virgin production, not recycled PET). This is particularly evident in cases involving PET with high requirements for shrinkage, deformability, elongation, and strength. Summary of the Invention

[0009] Therefore, the object of the present invention is to provide a rubberized reinforcing member for elastomer products (especially vehicle tires), wherein the reinforcing member comprises at least one first yarn having high strength and high ductility and being produced with maximum resource conservation, maximum sustainability and minimal environmental impact.

[0010] This objective is achieved by using HMLS-PET yarn containing recycled PET as the first yarn.

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

[0012] In the context of this invention, a first HMLS-PET yarn comprising recycled PET, preferably 10% to 100% by weight of recycled PET, is also referred to as a "first yarn".

[0013] Surprisingly, it is possible to provide a rubberized reinforcing member comprising at least one PET yarn, wherein the yarn contains recycled PET (preferably 10% to 100% by weight) and simultaneously has high modulus and therefore high strength as well as low shrinkage, and thus can be classified as HMLS-PET yarn.

[0014] The reinforcing member of the present invention has the following advantages: it can be produced in a more resource-efficient and environmentally friendly manner than virgin PET, while still meeting high performance requirements, especially for elastomer products such as carcass ply for vehicle tires.

[0015] The weight percentages (by weight %) are based on unrubberized and untreated (i.e., especially unimpregnated) yarns.

[0016] In the context of this invention, "recycled PET" should be understood to mean PET obtained from, for example, used PET products (such as PET bottles) or other PET articles (such as clothing).

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

[0018] Preferred methods for obtaining recycled PET with HMLS properties are described in detail below.

[0019] Further advantages and features of the reinforcing member of the invention become apparent from the dependent claims relating to advantageous configurations of the invention, and therefore should not be interpreted in a restrictive manner. The invention also covers combinations of features from technically possible different dependent claims, even if these dependent claims are unrelated to each other or belong to different claim classes. The same applies to individual features of the working examples discussed below, to the point that those skilled in the art would not recognize that these features necessarily belong together. The invention also covers combinations of features deemed preferred, particularly preferred, etc., for example, a first feature deemed "preferred" may be combined with another second feature deemed "particularly preferred," unless the contrary is clearly apparent from the content or for technical reasons.

[0020] If the reinforcing member contains less than 100% recycled PET by weight (i.e., for example, and especially 10% to <100% recycled PET by weight), the remaining components are virgin PET that has not undergone any recycling process and is derived from mineral oil (petrochemical) or renewable feedstock.

[0021] With the content of recycled PET in the first yarn ranging from 10% to 100% by weight, the cost and CO2 load of producing the rubberized reinforcing member and motor vehicle tire of the present invention can be adjusted individually.

[0022] The basic objective of this invention is achieved particularly efficiently through a higher proportion of recycled PET, but even a proportion of, for example, 10% recycled PET by weight helps to save resources and reduce CO2 load.

[0023] In an advantageous embodiment, the first HMLS-PET yarn comprises 20% to 100% recycled PET by weight.

[0024] In an advantageous embodiment, the first HMLS-PET yarn comprises 30% to 100% recycled PET by weight.

[0025] In an advantageous embodiment, the first HMLS-PET yarn comprises 40% to 100% recycled PET by weight.

[0026] In an advantageous embodiment, the first HMLS-PET yarn comprises 50% to 100% recycled PET by weight.

[0027] In an advantageous embodiment, the first HMLS-PET yarn comprises 60% to 100% recycled PET by weight.

[0028] In an advantageous embodiment, the first HMLS-PET yarn comprises 70% to 100% recycled PET by weight.

[0029] In an advantageous embodiment, the first HMLS-PET yarn comprises 80% to 100% recycled PET by weight.

[0030] In an advantageous embodiment, the first HMLS-PET yarn comprises 90% to 100% recycled PET by weight.

[0031] In an advantageous embodiment, the first HMLS-PET yarn comprises 100% recycled PET by weight.

[0032] Particularly preferred is that the HMLS-PET yarn contains 30% to 100% by weight, more preferably 50% to 100% by weight, of recycled PET.

[0033] The difference between recycled PET and virgin PET lies in the amount of additives, particularly isophthalic acid (IPA). These additives (especially IPA) are present, for example, and specifically in PET bottles.

[0034] Although virgin PET has 0% isophthalic acid content by weight, recycled PET can have up to 5% IPA content by weight.

[0035] More specifically, in the context of this invention, the recycled PET contains, for example and particularly, 1.2% to 2.2% by weight.

[0036] The weight percentages (by weight %) are based on PET, and therefore in the reinforcing members of the present invention, they are based on unrubberized and untreated (i.e., especially unimpregnated) yarns.

[0037] In the case of 10% recycled PET and 90% virgin mineral oil-based PET by weight, the isophthalic acid content is therefore 0.12% to 0.5% by weight, preferably 0.12% to 0.22% by weight.

[0038] Therefore, the first HMLS-PET yarn preferably has an isophthalic acid (IPA) content of 0.12% to 5% by weight, for example and preferably 0.12% to 2.2% by weight.

[0039] "HMLS yarn" should be understood here as referring to high modulus, low shrinkage yarn.

[0040] The first HMLS-PET yarn here particularly and preferably has a heat shrinkage rate of less than 8%, more preferably 4% to 8%, and an elongation at 45N of less than 0.0056% / den (percentage / denier), more preferably 0.002 to 0.0056% / den, and a filament fineness of less than 5den, more preferably 3 to 5den.

[0041] These values ​​are particularly suitable for describing the first HMLS-PET yarn as an HMLS yarn.

[0042] The first yarn of the reinforcing member of the present invention preferably has a breaking strength of 7.0 to 9.0 g / den.

[0043] The first yarn of the reinforcing member of the present invention preferably has an elongation at break of 10.2% to 15.5%.

[0044] The first yarn is, in particular and preferably, a continuous multifilament yarn and therefore preferably not a monofilament yarn and preferably not a staple fiber yarn.

[0045] The first yarn of the reinforcing member of the present invention preferably comprises filaments with a filament fineness of less than 5 denier, which means that each filament of the yarn is preferably finer than 5 denier. More preferably, the first yarn has a filament fineness of 3 to 5 denier.

[0046] Preferably, the first yarn has an elongation of less than 0.0056% / den at a force of 45N.

[0047] In the context of this invention, tensile strength, elongation at 45 N, and elongation at break were determined according to ASTM D885 using an Instron tensile testing machine: Instron 5564 instrument, clamp: C-type clamp, 2714-004 pneumatically activated, load capacity 1 kN (1 kilonewton), test conditions: gauge length 250 mm, crosshead speed 300 mm / min, preload 0.05 gf / den (grams / denier), air pressure 0.4 to 0.6 MPa, sample conditioning before testing: 24 ± (plus / min) 2 °C, 55 ± 5% humidity for 24 hours.

[0048] The first yarn of the reinforcing member of the present invention preferably has a heat shrinkage rate of 3.2% to 5.2% at 177°C.

[0049] In the context of this invention, the heat shrinkage rate of the yarn was determined by the heat shrinkage method according to ASTM D885. The test conditions were: temperature 177°C, load 0.05 g / den, duration 10 min.

[0050] The first HMLS-PET yarn preferably has a crystallinity level of 45% to 53.5%.

[0051] The crystallinity level was determined according to ASTM D1505 as follows: First, the yarn density was determined using a density gradient column. Then, the crystallinity level was calculated by interpolation using literature values ​​for the densities of 100% amorphous and 100% crystalline PET, as specified below. The density of 100% amorphous PET is 1.333 g / cm³. 3 The density of 100% crystalline PET is 1.455 g / cm³. 3 .

[0052] At this level of crystallization, the yarns of the present invention, and thus the reinforcing members, are producible and simultaneously possess the necessary properties in terms of high required elongation and shrinkage characteristics, especially in the case of carcass ply for vehicle tires.

[0053] Preferably, the first HMLS-PET yarn has a fineness of 300 to 4000 denier, more preferably 300 to 3100 denier, more preferably 300 to 2000 denier, and most preferably 900 to 2000 denier.

[0054] In a first embodiment, the first yarn is twisted and further processed as described below. In this embodiment, the reinforcing member of the present invention comprises twisted rubberized yarn.

[0055] In another advantageous embodiment, one or more yarns may be twisted to form a cord. In each case, the first yarn, as described in the invention, is preferably an HMLS-PET yarn containing 10% to 100% recycled PET by weight.

[0056] In a particularly preferred embodiment, at least one additional (second) yarn is also an HMLS-PET yarn, which contains

[0057] Preferably, the recycled PET comprises 10% to 100% by weight, such that in this embodiment, at least two of these HMLS-PET yarns are twisted together to form a cord.

[0058] In an advantageous embodiment of the invention, the first yarn is twisted into a x2 cord, wherein the cord has a twist coefficient of 150 to 250, preferably 170 to 230, and a breaking strength of at least 6.3 g / den, preferably 6.3 to 10 g / den, and has 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 term "x2 cord" refers to two yarns twisted together.

[0060] In the embodiment described, a first yarn—such as an HMLS-PET yarn containing recycled PET according to the present invention—is preferably twisted with a second additional HMLS-PET yarn containing recycled PET to obtain a cord.

[0061] In the context of this invention, the heat shrinkage rate of the cord was determined according to ASTM D885 by the heat shrinkage method at 180°C. The test conditions were: temperature 180°C, load 0.05 g / den, duration 10 min.

[0062] In a further preferred embodiment, it is alternatively conceivable that at least one additional yarn is a different yarn and therefore the reinforcing member of the invention is a hybrid cord comprising HLMS-PET yarn preferably containing 10% to 100% recycled PET by weight and at least one additional yarn. This at least one additional yarn is preferably a non-metallic material or composed of non-metallic materials. The non-metallic material is preferably selected from the group consisting of: polyamide (PA) and / or aramid and / or polyetherketone (PEK) and / or polyketone (POK) and / or polyethylene naphthalate (PEN) and / or rayon and / or cellulose adhesive and / or natural fibers and / or glass fibers.

[0063] In a preferred embodiment, the yarn and / or the cord are woven to form a fabric layer, which is then further processed by activated adhesion and rubberization with a rubberizing mixture.

[0064] The present invention further provides a reinforcing member layer composed of a plurality of rubberized reinforcing members of the present invention.

[0065] The present invention further provides a vehicle tire comprising at least one rubberized reinforcing member of the present invention.

[0066] In an advantageous embodiment of the invention, the vehicle tire includes a plurality of the rubberized reinforcing members of the invention in the reinforcing member layer.

[0067] The reinforcing member layer is preferably a carcass ply and / or belt ply and / or hoop ply and / or bead reinforcement, more preferably at least a carcass ply.

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

[0069] In an advantageous embodiment of the invention, the reinforcing member layer is at least a carcass ply, wherein the carcass ply is rolled up once (single-layer construction) or twice (double-layer construction) around the bead, wherein the ends of the one or more carcass ply are located between the core and the edge of the belt.

[0070] In this way, vehicle tires can achieve their required load-bearing capacity (taking into account the corresponding load index).

[0071] In an advantageous development of this embodiment, in addition to one or two carcass ply layers surrounding the bead, another reinforcing member layer including the reinforcing member of the present invention is arranged in the sidewall up to or below the bead.

[0072] This further improves the load-bearing capacity of the vehicle's tires.

[0073] A particularly preferred method is described below for obtaining a first yarn for a rubberized reinforcing member. As described, the yarn is produced as a continuous multifilament yarn. Unless otherwise stated, the method steps described in detail are carried out using equipment known to those skilled in the art.

[0074] a) Provide PET chips containing 100% recycled PET from PET bottles or other PET products by weight, and optionally provide virgin PET chips;

[0075] b) Pre-crystallize, crystallize and solid-state polymerize (SSP) the PET chips from step a) to obtain high-viscosity PET chips with an intrinsic viscosity of 0.85 to 1.15 dl / g.

[0076] c) Drying, optionally mixing recycled PET chips with virgin PET chips to obtain PET chips—which comprise up to 10% to 100% by weight chips from recycled PET.

[0077] These PET chips are melted and extruded for spinning, then spun through a spinneret including a reheater with a buffer, and the unstretched yarn is gradually cooled, wherein the moisture content of these chips after drying is less than 30 ppm, the temperature of the reheater below the spinneret is 280°C to 350°C, and the length of the buffer below the reheater during the gradual cooling is 20 to 100 mm.

[0078] d) After the gradual cooling in step c), oiling, stretching, heat setting and winding are performed to obtain HMLS-PET yarn.

[0079] Those skilled in the art are aware of the fact that recycled PET can be provided in the form of chips. Chips can also be referred to as "granules".

[0080] "PET chips containing 100% by weight recycled PET from PET bottles or other PET products" are also referred to herein as "recycled PET chips".

[0081] In the context of this invention, the intrinsic viscosity is determined by an Ubbelohde capillary viscometer according to ASTM D4603.

[0082] If the yarn contains less than 100% recycled PET by weight (i.e., especially 10% to <100% recycled PET by weight), the remaining components are virgin PET that has not undergone any recycling process and is derived from mineral oil (petrochemical) or renewable feedstock.

[0083] In this case, in an additional process step—referred to above as “optional mixing”—recycled PET chips and virgin PET chips are mixed together before the spinning process. This mixing is preferably carried out in a single-screw conveyor system after the drying step.

[0084] If 100% recycled PET by weight is used, the additional mixing step is unnecessary and the slices are dried and extruded directly.

[0085] Additives present in recycled PET, such as alternative monomers to terephthalic acid (e.g., IPA), impair PET's ability to crystallize during the spinning process. This complicates spinning and stretching to form yarn, resulting in yarn with deteriorated properties compared to virgin PET yarn.

[0086] The pre-crystallization, crystallization, and solid-state polymerization (SSP) in step b) enables further polymerization and thus reduces the proportion of shorter polymer molecules, resulting in molecular chain growth. This leads to an increase in intrinsic viscosity. This improves the stretchability of the material, and also improves the tensile stiffness and modulus (stiffness) of the yarn.

[0087] By combining pre-crystallization and crystallization with the temperature of the reheater below the spinneret at 280°C to 350°C in step c) and the length of the buffer zone below the reheater during the gradual cooling period of 20 to 100 mm, the crystallization rate can be adjusted in a way that allows for the selection of high spinning speed and high stretching rate during the spinning process.

[0088] In addition, the frequency of filament and yarn breakage is reduced, which results in yarns with high tensile stiffness and high modulus.

[0089] Solid-state polymerization (SSP) is a method in which coarse PET chips are placed in a reactor and heated to polymerize. This increases the molecular chain length and intrinsic viscosity. The intrinsic viscosity of recycled PET chips is 0.55 to 0.75 dl / g.

[0090] Solid-state polymerization is also known as solid-phase condensation because the expulsion of water leads to condensation.

[0091] More preferably, these original slices, which still have relatively low viscosity, are treated as follows:

[0092] Preferably, the original PET chips are pre-crystallized at 150°C to 180°C for 0.5 to 1.5 hours, then crystallized at 200°C to 230°C for 4 to 6 hours, and finally reacted in an SSP reactor with a wall temperature of 200°C to 220°C for 30 to 35 hours.

[0093] The entire equipment system operates in a nitrogen atmosphere, wherein the oxygen content of the nitrogen is maintained at 30 to 70 ppm and the dew point is preferably below -70°C (below -70°C).

[0094] The intrinsic viscosity of the original PET chips is increased to 0.85 to 1.15 dl / g, resulting in high-viscosity chips.

[0095] Preferably, drying is carried out under nitrogen in step c), wherein the drying temperature is preferably between 120°C and 160°C and the drying time is preferably greater than 8 hours. This reduces the water content of the high-viscosity chips to less than 30 ppm.

[0096] Preferably, in step c), the high-viscosity PET chips are melted and extruded in a screw extruder via melt extrusion, wherein the temperature in the feed zone of the screw extruder is 300°C to 330°C, the temperature in the compression zone is 290°C to 320°C, and the temperature in the metering zone (discharge zone) is 280°C to 310°C, and the pressure at the extruder head is 14 to 18 MPa. This provides the melt.

[0097] Melt extrusion can also improve the melt viscosity and flowability of high-viscosity chips, further reduce the adverse effects caused by IPA content, and thus further improve stretchability.

[0098] If the high-viscosity chips from recycled PET have been pre-mixed with the virgin PET chips, the extrusion step further improves the homogeneity of the mixture of recycled and virgin PET.

[0099] Spinning (in step c) is preferably carried out through a spinneret, wherein in an advantageous embodiment, the length-to-diameter ratio (L / D) of the spinneret orifice is 1.2 to 3.0.

[0100] In an advantageous embodiment, the spinneret includes 180 to 480 holes and produces yarn with a denier of 1,000 to 1,500.

[0101] In a further advantageous embodiment, yarns with deniers of 300 to 4000, preferably 300 to 3100, more preferably 300 to 2000, and even more preferably 900 to 2000, such as and especially 500, 2000, or 4000 denier, can be obtained. If a fineness greater than 1500 denier is selected, the number of spinnerets can be greater than 480.

[0102] Preferably, a yarn having filaments with a fineness of less than 5 denier is obtained. More preferably, a yarn having filaments with a fineness of 3 to 5 denier is obtained.

[0103] The purpose of gradual cooling in step c) is to solidify the melt of the unstretched yarn.

[0104] Preferably, the gradual cooling in step c) includes an annular quench system downstream of the buffer zone, wherein cooling air is blown into the inner ring from the outside at a pressure of 15 to 50 Pa and a temperature of 22°C to 65°C.

[0105] This prevents the adhesion of unstretched yarn, which simplifies or does not complicate the downstream stretching process in step d). Optimal parameters for the blowing air pressure and temperature prevent excessively fast or slow cooling, which in turn prevents the adhesion of unstretched yarn and the deterioration of its physical properties.

[0106] If the unstretched yarn cools too quickly, stretching (especially during spinning) becomes more difficult.

[0107] If unstretched yarn cools too slowly, there is a particular risk of increased adhesion and deterioration of physical properties.

[0108] For the reasons mentioned above, it is particularly advantageous to reheat the unstretched yarn after melt spinning, gradually cool it through an annular quenching system downstream of the buffer zone, and then cool it with cooling air.

[0109] The oiling in step d) has the advantage of increasing the cohesion of the unstretched yarn, as well as reducing friction and static charge. This also facilitates downstream stretching processes and reduces the frequency of filament and yarn breakage. Furthermore, it is advantageous for downstream processing steps that produce rubberized reinforcing members or braided layers (i.e., especially for twisting and braiding), as the yarn becomes smoother due to the oiling.

[0110] Preferably, the oil is used in the form of an emulsion, and based on the yarn, the oil absorption rate is preferably 0.3% to 0.9% by weight.

[0111] The stretching in step d) is preferably performed by a guide roller configuration, wherein the first guide roller pair (GR1) operates at a temperature of 60°C to 80°C at a speed of 2700 to 3200 m / min, the second guide roller pair (GR2) operates at a temperature of 70°C to 90°C at a speed of 3800 to 5000 m / min, and the third guide roller pair (GR3) operates at a temperature of 210°C to 260°C at a speed of 5800 to 6200 m / min, and the stretching rate is preferably 1.81% to 2.30%.

[0112] In this way, the optimal properties of the produced yarn can be achieved, such as optimized breaking strength and elongation at break, as well as optimized heat shrinkage and modulus.

[0113] Preferably, the heat setting that occurs here after stretching is carried out by the fourth guide roller pair (GR4) at a temperature of 210°C to 260°C and a speed of 5800 to 6200 m / min, the downstream fifth guide roller pair (GR5) at a temperature of 210°C to 260°C and a speed of 5600 to 6200 m / min, and the downstream sixth guide roller pair (GR6) at a temperature of 100°C to 150°C and a speed of 5450 to 6000 m / min, wherein the relaxation rate is 2.5% to 6.0%.

[0114] In this way, optimal crystallization, stable microstructure, optimal breaking strength, optimal modulus, and reduced heat shrinkage can be achieved. Therefore, the yarn is optimally prepared for downstream winding and heat setting processes.

[0115] The winding in step d) is preferably performed at a winding speed of 5450 to 5950 m / min.

[0116] By means of steps a) to d), yarns with a breaking strength of 7.5 to 9.0 g / d, an elongation at break of 10.2% to 15.5%, a heat shrinkage of 3.2% to 5.2%, a crystallinity of 45% to 53.5%, and an IPA content of 0.12% to 5% by weight (especially 0.12% to 2.2% by weight) were obtained.

[0117] In addition, yarns with a fineness of 300 to 4000 denier can be obtained.

[0118] The resulting HMLS-PET yarn, containing 10% to 100% recycled PET by weight, is further processed, particularly and preferably, by at least the following steps, to obtain the rubberized reinforcing member of the present invention:

[0119] e) Twisting;

[0120] f) Weave as you please;

[0121] g) Modify adhesion by impregnation;

[0122] h) Rubberize with a rubberizing mixture.

[0123] In an advantageous embodiment of the invention, the yarn itself is first twisted, and then twisted together with another equally twisted yarn to form a cord.

[0124] The yarns used in the cord can each be formed from filaments twisted in the S or Z direction. Therefore, for example, HMLS-PET yarn containing recycled PET can be S- or Z-twisted.

[0125] The twisted yarns are then twisted in the S or Z direction to form a reinforcing cord. Advantageously, all the yarns of the reinforcing cord have the same direction of rotation, i.e., they are twisted in the S or Z direction. In this advantageous variant, the reinforcing cord has a direction of rotation opposite to that of the yarns. For example, an S-twisted HMLS-PET yarn containing recycled PET can ultimately be twisted in the Z direction with another S-twisted HMLS-PET yarn (containing recycled PET) to form a reinforcing cord.

[0126] Alternatively, it is conceivable to obtain corresponding hybrid cords, wherein, for example, an S-twisted HMLS-PET yarn containing recycled PET is ultimately twisted with other yarns. Illustrative and preferred materials for other yarns have been listed above.

[0127] In an advantageous embodiment of the invention, two yarns are twisted in a direct twisting machine to form a cord (x2 cord) from the two yarns.

[0128] In each case, the twist count (tpm "twist / meter") of the yarn and cord is preferably between 100 and 500 tpm.

[0129] The cord containing the first yarn preferably has a twist coefficient TF of 150 to 250. The twist coefficient is calculated using formula I) as follows:

[0130] I)TF=N*(K / 9000)^0.5

[0131] Where N is the twist count (in tpm) and K is the cord fineness, and ^0.5 should represent the square root (of the expression in parentheses), i.e.

[0132] TF = twist count (in tpm) * (multiple) [cord fineness (in denier) / 9000]^0.5 (powered by 0.5).

[0133] The following should preferably be noted during weaving (step f):

[0134] When arranging yarns on the packaging bobbin rack, the strain on each bundle of yarn is controlled by roller bearings and rubber belts to ensure uniform strain. During the weaving process, the yarns are guided by reeds adapted according to specifications and woven on an air-jet braiding machine. The woven cords then produce a fabric of a predetermined width, with the weft yarns being, in particular, yarns with a PET or nylon elastic core (e.g., wrapped with cotton).

[0135] The fabric obtained in step f) is then further processed in step g) by impregnation. Thus, the reinforcing components (especially yarns or cords) are endowed with desirable physical properties and optimized adhesion to the subsequently applied rubberized compound.

[0136] More specifically, impregnation may include pre-impregnation and RFL (resorcinol-formaldehyde latex) impregnation known in the art or RFL-free alternatives that are harmless to the environment and health, such as those described, for example, in DE 102014211362 A1 or WO 2019015792A1.

[0137] Therefore, the alteration of adhesion by impregnation in step g) can in particular include the 1-bath or 2-bath (pre-impregnation and impregnation) methods known in the art.

[0138] During the impregnation process, apparatus and conditions known in the art, such as impregnation solution baths, stretching zones, and ovens, are used sequentially. This stretches the fabric or cord (depending on whether it is woven according to step f) by 0% to 8%, particularly 0% to 3%.

[0139] The rubberization in subsequent step h) is carried out in a manner known to those skilled in the art using a rubberizing mixture and equipment known to those skilled in the art. This may include drying at high temperatures (especially above 100°C) prior to rubberization.

[0140] Rubberized mixtures can be those known to those skilled in the art for covering reinforcing members, especially

[0141] Any suitable rubberized compound for fabric-reinforced components.

[0142] The rubberized mixture preferably contains at least one diene rubber.

[0143] Diene rubber is a rubber formed by the polymerization or copolymerization of dienes and / or cyclic olefins, and therefore has C=C double bonds in the main chain or side groups.

[0144] In an advantageous embodiment, 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).

[0145] In an advantageous embodiment, the rubberized mixture contains at least one type of carbon black as a non-polar filler.

[0146] Carbon black is preferably used in the rubberized compound in an amount of 0.1 to 100 phr, more preferably 40 to 100 phr, and most preferably 40 to 80 phr. It is particularly preferred that the rubber compound contains at least one type of carbon black at 57 to 67 phr. In this way, particularly good compound properties in terms of tear resistance are achieved.

[0147] The present invention further provides a method comprising at least steps a) to h). The reinforcing member of the present invention is preferably produced by this method. Therefore, the present invention further provides a reinforcing member obtained by said method. Detailed Implementation

[0148] The invention will now be described in detail through some working examples. In this regard, firstly, Table 1 provides an overview of the yarns used in the reinforcing members of the invention by way of example and their production parameters.

[0149] Except for the specifically specified parameters, the above description also applies here. More specifically, in all examples E1 to E6, the method according to steps a) to d) is carried out, including solid-state polymerization as described above. The original PET chips are pre-crystallized at a temperature of 150°C to 180°C for 0.5 to 1.5 hours and then crystallized at a temperature of 200°C to 230°C for 4 to 6 hours, and finally reacted in an SSP reactor with a wall temperature of 200°C to 220°C for 30 to 35 hours.

[0150] The entire equipment system operates in a nitrogen atmosphere, wherein the oxygen content of the nitrogen is maintained at 30 to 70 ppm and the dew point is preferably below -70°C (below -70°C).

[0151] Table 1

[0152]

[0153]

[0154] exist Figure 1 The diagram shows bar graphs depicting the proportions of Examples E1 to E6 relative to recycled PET, where the height of the bars represents CO2 emissions (kg CO2 / kg product). These figures are based on PET chip production and do not include contributions to monomer production such as monoethylene glycol (MEG) and PTA (purified terephthalic acid). Subsequent processes, starting from yarn production, are considered independent of CO2 emissions from PET raw materials.

[0155] The bar on the left represents the CO2 emissions of raw PET, while the two bars on the right represent the CO2 emissions of bio-based PET (the ethylene glycol monomer is obtained from corn, making approximately 30% of the raw material by weight from renewable sources) and HIPS (high-impact polystyrene).

[0156] As from Figure 1 Clearly, the lowest CO2 emissions are achieved using PET produced from 100% recycled PET by weight. For example, the CO2 balance of the recycled material only begins after it is used as a PET bottle.

[0157] The “primitive PET” and “bioPET” labels do not include CO2 emissions because the monomers are made from different raw materials. This means that these values ​​essentially include the condensation into PET chips.

[0158] In the case of 100% recycled PET, this value essentially includes crushing and remelting to obtain PET chips.

[0159] The value between the two (i.e., 10% to 90% PET) is calculated by proportionally combining the values ​​of “original PET” and 100% recycled PET.

[0160] In addition, further experiments were conducted, using 100% recycled PET (like E1) by weight in each experiment, but with different method steps adjusted in each case.

[0161] The procedure for comparative experiment V2 was the same as that for E1, except that the entire solid-state polymerization process was omitted.

[0162] The procedure for comparative experiment V3 was the same as that for E1, except that solid-state polymerization was carried out without pre-crystallization and crystallization steps.

[0163] The procedure for comparative experiment V4 was the same as that for E1, except that the unstretched yarn was cooled directly by cooling air after the spinning process without reheating in the buffer zone (see step c).

[0164] The procedure for comparative experiment V5 is the same as that for E3, except that the unstretched yarn is cooled directly by cooling air after the spinning process without reheating in the buffer zone (see step c).

[0165] Table 2 shows the effects of different processing methods on the physical properties of the corresponding yarns.

[0166] The characteristics are determined using the methods described above.

[0167] Another standard used is the filament breakage level during the yarn production process. For each yarn bobbin (9kg, 62km long, 1300den), the number of broken filaments must be less than 10 to be classified as acceptable (Q). Otherwise, the sample is rated as unacceptable (NQ).

[0168] Table 2

[0169]

[0170]

[0171] The data in Table 2 show that the yarns produced by the methods including steps a) to d) (including solid-state polymerization, spinning, cooling processes, and stretching processes) have properties comparable to conventionally produced yarns, such as breaking strength and elongation at break. Therefore, the rubberized reinforcing members of the present invention, and especially vehicle tires incorporating the rubberized reinforcing members in the reinforcing member layers, can be produced efficiently and with a low failure rate (<4%) using the yarns according to Examples E1 to E6, while ensuring that the corresponding usage requirements are met due to their high-quality properties.

[0172] Compared to V2, solid-state polymerization in E1 enables molecular chain growth and reduces the amount of additives present in recycled PET, such as alternative monomers for terephthalic acid, like IPA.

[0173] Compared to V3, pre-crystallization and crystallization in E1, as part of the solid-state polymerization process, improve the quality and processability of high-viscosity chips and reduce adverse effects in the SSP reactor, such as agglomeration and clumping. If these adverse effects occur, they lead to irregular discharge from the SSP reactor and increased differences in the intrinsic viscosity of the high-viscosity chips. Furthermore, this results in further adverse consequences, such as heterogeneous melting point, heterogeneous melting characteristics, and heterogeneous crystallization rate of the yarn. This increases the breakage frequency of filaments and yarns and generally makes yarn production significantly more difficult.

[0174] If pre-crystallization and crystallization are carried out as part of a solid-state polymerization process, the uniformity of viscosity, melting point, and crystallization rate of high-viscosity chips can be effectively controlled.

[0175] Without the SSP process, the breaking strength of the produced yarn will not meet the requirements, the breaking frequency of filaments and yarns will increase, and production efficiency will decrease.

[0176] Example V4 shows that, without reheating and buffering after spinning, the unstretched yarn cools too quickly and hardens and crystallizes prematurely, resulting in lower production efficiency and poorer physical properties.

[0177] Example V5 shows that, by omitting pre-crystallization and crystallization in the SSP process and omitting reheating and buffer after spinning, uniformity of high viscosity chip difference, rapid crystallization rate during spinning, and poor spinnability and low crystallization level of the finished yarn are achieved.

[0178] Therefore, pre-crystallization and crystallization should be combined with reheating and buffering as described above in order to slow down the crystallization rate and increase the level of crystallization.

[0179] The yarns listed above, E1 to E6 and V2 to V5, are each used to produce cords by twisting two yarns together, and these cords are woven and impregnated to obtain impregnated fabric.

[0180] Twisting is performed by twisting two yarns in a direct twisting machine to form a cord (x1x2 cord) from the two yarns.

[0181] The yarn is twisted in the S direction, while the cord is twisted in the Z direction.

[0182] The following conditions were observed during weaving:

[0183] When arranging the yarn on the packaging bobbin rack, the strain on each bundle of yarn is controlled by roller bearings and rubber belts to ensure uniform strain. During the weaving process, the yarn is guided by reeds adapted according to specifications and woven on an air-jet braiding machine. The cords are then woven to form a greige fabric of a preset width, and the weft yarns are 22.2 tex nylon core-spun yarns (the core consists of nylon monofilaments covered with short cotton fibers).

[0184] The resulting fabric is then further processed through impregnation. A two-bath impregnation method is used here. An epoxy compound (trade name: [trade name missing]) is provided in the first bath. G 1701 (from EMS-GRILTECH) and isocyanate compounds (trade name: IL-6 50%F (from EMS-GRILTECH) is used to impregnate the yarn and thus activate the filaments on its surface.

[0185] In the second bath, resorcinol-formaldehyde latex (a precondensed resin of resorcinol and formaldehyde in an aqueous dispersion, particularly mixed with formaldehyde and latex) is provided, and the fabric activated by the first bath is impregnated therein. During the impregnation process, apparatus and conditions known in the art, such as impregnation solution tanks, stretching zones, and ovens, are used successively.

[0186] In addition, hot stretching resulted in a net stretching rate of 0% to 1%.

[0187] Examine the characteristics of the obtained cords and summarize the results in Table 3.

[0188] Item 1500 / 2 should be read as 1500den / 2 and means twisting two yarns, each with a fineness of 1500den, together to form a cord. The same applies to item 1000 / 2.

[0189] The twist count per meter (tpm) in Table 3 is related to the corresponding cord.

[0190] Residual strength was determined by Goodrich fatigue testing under the following conditions: 1800 rpm, duration: 24 hours, 20% compression, 6.5% strain, at room temperature.

[0191] Table 3

[0192]

[0193] As is evident from Table 3, examples E1 to E6 can produce cords with properties that meet the requirements for rubberized reinforcing members used in the present invention (especially for vehicle tires). In contrast, comparative examples V2 to V5 show inferior properties and are therefore unsuitable. The major damage to the filaments during high-speed spinning particularly means that the fatigue resistance of the produced cords is significantly adversely affected. As is evident from example V2, the sample broke before the fatigue test was completed.

[0194] Therefore, as illustrated by Examples E1 to E6, the rubberized reinforcing members of the present invention can be provided for elastomer products (especially vehicle tires), which are produced in a particularly resource-saving and environmentally friendly manner and simultaneously possess good physical properties, enabling them to meet requirements, especially in the driving operation of vehicle tires. Furthermore, the vehicle tires of the present invention include rubberized reinforcing members at least in the carcass ply, and particularly in the respective reinforcing member layers forming the carcass ply, including multiple rubberized reinforcing members.

[0195] The illustrative composition of the rubberized mixture of the rubberized reinforcing member of the present invention is shown in Table 4.

[0196] Table 4

[0197]

[0198] a) Oil filled with 27.3% aromatic-free oil.

[0199] b) 65% on inorganic carriers

Claims

1. A rubberized reinforcing member for elastomer products, wherein the reinforcing member comprises at least one first yarn, characterized in that, The first yarn is a first HMLS-PET yarn comprising recycled PET, wherein the first HMLS-PET yarn contains 0.12% to 5% isophthalic acid by weight, and wherein the first HMLS-PET yarn has a crystallinity level of 45% to 53.5%, and wherein the first HMLS-PET yarn here has a heat shrinkage of less than 8% and an elongation at 45N of less than 0.0056% / den.

2. The rubberized reinforcing member as described in claim 1, characterized in that, The first HMLS-PET yarn contains 10% to 100% recycled PET by weight.

3. The rubberized reinforcing member as described in claim 2, characterized in that, The first HMLS-PET yarn contains 30% to 100% recycled PET by weight.

4. The rubberized reinforcing member as described in claim 3, characterized in that, The first HMLS-PET yarn contains 50% to 100% recycled PET by weight.

5. The rubberized reinforcing member as described in claim 1, characterized in that, The first HMLS-PET yarn contains 0.12% to 2.2% isophthalic acid by weight.

6. The rubberized reinforcing member as described in claim 1, characterized in that, The first HMLS-PET yarn has a fineness of 300 to 4000 denier.

7. The rubberized reinforcing member as described in claim 6, characterized in that, The first HMLS-PET yarn has a fineness of 300 to 3100 denier.

8. The rubberized reinforcing member as described in claim 6, characterized in that, The first HMLS-PET yarn has a fineness of 300 to 2000 denier.

9. The rubberized reinforcing member as described in claim 6, characterized in that, The first HMLS-PET yarn has a fineness of 900 to 2000 denier.

10. The rubberized reinforcing member as claimed in claim 1, characterized in that, With a filament fineness of less than 5 den, the first HMLS-PET yarn has a heat shrinkage rate of less than 8% and an elongation at 45 N of less than 0.0056% / den.

11. The rubberized reinforcing member as claimed in claim 1, characterized in that, The first yarn is twisted into x2 cords, wherein the cords have a twist coefficient of 150 to 250 and a breaking strength of at least 6.3 g / den, and have an elongation of less than 0.0056% / den at 45 N and a heat shrinkage of less than 3%.

12. The rubberized reinforcing member according to any one of claims 1 to 11, characterized in that, The elastomer product is a vehicle tire.

13. A method for producing a rubberized reinforcing member having at least one first HMLS-PET yarn comprising recycled PET, the method comprising at least the following steps: a) Provide PET chips containing 100% recycled PET from PET bottles or other PET products by weight, and optionally provide virgin PET chips; b) The PET from step a) is pre-crystallized, crystallized, and solid-state polymerized to obtain high-viscosity PET chips with an intrinsic viscosity of 0.85 to 1.15 dl / g; c) Drying: The recycled PET chips are mixed with virgin PET chips to obtain PET chips containing up to 10% to 100% by weight of chips from recycled PET. The PET chips are melted and extruded for spinning, then spun through a spinneret including a reheater with a buffer, and the unstretched yarn is gradually cooled. The moisture content of the dried chips is less than 30 ppm. The temperature of the reheater below the spinneret is 280°C to 350°C, and the length of the buffer below the reheater during the gradual cooling is 20 to 100 mm. d) After the gradual cooling in step c), oiling, stretching, heat setting, and winding are performed to obtain HMLS-PET yarn; e) Twisting; f) Weaving; g) Modify adhesion by impregnation; h) Rubberize with a rubberizing mixture.

14. A vehicle tire comprising at least one rubberized reinforcing member as claimed in any one of claims 1 to 12.

15. The vehicle tire as claimed in claim 14, characterized in that, The vehicle tire includes a plurality of rubberized reinforcing members as described in any one of claims 1 to 12 in the reinforcing member layer.

16. The vehicle tire as claimed in claim 15, characterized in that, The reinforcing member layer is at least a carcass ply and / or a belt hoop and / or a belt layer and / or a bead reinforcement.

17. The vehicle tire as claimed in claim 16, characterized in that, The reinforcing member layer is at least the carcass ply, wherein the carcass ply is rolled up once around the bead, i.e., a single-layer construction or twice, i.e., a double-layer construction, wherein the ends of the one or more carcass ply are located between the edges of the core and the belt.

Images