Wear-resistant floor mat for cab and preparation method of wear-resistant floor mat

Abstract

The invention relates to the technical field of high polymer materials, and discloses a wear-resistant floor mat for a cab and a preparation method of the wear-resistant floor mat. 20 to 30 parts of a metallocene polyolefin elastomer; 25 to 35 parts of modified ultra-high molecular weight polyethylene powder; 40 to 50 parts of calcined kaolin; 3 to 4 parts of nano zinc oxide; 0.5 to 0.8 part of stearic acid; 0.5 to 0.8 part of an anti-aging agent; 1.5 to 2.0 parts of a crosslinking auxiliary agent; 2.0 to 2.5 parts of a first peroxide cross-linking agent; and 0.5 to 0.8 part of a second peroxide cross-linking agent. The method comprises the following steps: mixing raw materials to obtain a rubber compound; adding a cross-linking agent and flaking; a particle interface is locked through first-stage vulcanization, and deep curing is performed through second-stage vulcanization. Through interface chemical bonding and gradient vulcanization, the floor mat has the characteristics of high wear resistance, skid resistance and low odor, and the problems that the floor mat of the cab is easy to wear and fall scraps and has heavy peculiar smell are solved.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a wear-resistant floor mat for a driver's cab and its preparation method. Background Technology

[0002] The cab floor mat is a key interior component laid at the bottom of the vehicle cab. It is mainly used to cover the metal floor of the vehicle body and plays a role in sound insulation, noise reduction, shock absorption, and anti-slip protection. Its performance directly affects the safety of driving operations and the comfort of the interior environment.

[0003] In existing technologies, cab floor mats typically use natural rubber, styrene-butadiene rubber, or EPDM rubber as the base material. In terms of manufacturing processes, sulfur vulcanization systems are commonly used for cross-linking, and carbon black or conventional inorganic fillers are added to enhance the material's physical and mechanical strength, thereby meeting basic usage requirements.

[0004] However, the aforementioned existing technologies have significant shortcomings in practical applications. First, the driver's heel contact area is subjected to high-frequency friction and shear force for extended periods. Ordinary rubber matrices lack sufficient wear resistance, easily leading to localized wear, chipping, and even perforation. Simply increasing the hardness of the matrix to enhance wear resistance would reduce the surface friction coefficient of the floor mat, resulting in poorer anti-slip performance, making it difficult to balance wear resistance and anti-slip properties. Second, some technologies attempt to introduce wear-resistant particles such as ultra-high molecular weight polyethylene, but due to their high surface chemical inertness and weak interfacial bonding with the rubber matrix, particles are prone to peeling and detachment during use. Furthermore, traditional sulfur vulcanization systems release volatile organic compounds such as sulfides during production and use, resulting in a strong odor that fails to meet the environmental protection requirements for air quality in modern enclosed driving cabins.

[0005] Therefore, this invention proposes a wear-resistant floor mat for a driver's cab and its preparation method to overcome the shortcomings of the prior art. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a wear-resistant floor mat for driver's cabs and its preparation method, solving the problems of existing rubber floor mats having difficulty in achieving both wear resistance and anti-slip properties, weak interfacial bonding of wear-resistant particles that are prone to falling off, and a strong odor in the product.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] In a first aspect, the present invention provides a wear-resistant floor mat for a driver's cab, employing the following technical solution.

[0009] A wear-resistant floor mat for a driver's cab, made from raw materials comprising the following parts by weight:

[0010] EPDM rubber: 100 parts; metallocene polyolefin elastomer: 20-30 parts; modified ultra-high molecular weight polyethylene powder: 25-35 parts; calcined kaolin: 40-50 parts; nano zinc oxide: 3-4 parts; stearic acid: 0.5-0.8 parts; antioxidant: 0.5-0.8 parts; crosslinking aid: 1.5-2.0 parts; first peroxide crosslinking agent: 2.0-2.5 parts; second peroxide crosslinking agent: 0.5-0.8 parts.

[0011] By adopting the above technical solution, this invention utilizes EPDM rubber as the continuous phase matrix, metallocene polyolefin elastomer as the toughening phase, and modified ultra-high molecular weight polyethylene powder as the wear-resistant dispersed phase. EPDM rubber provides weather resistance and basic elasticity; metallocene polyolefin elastomer improves the processing fluidity of the rubber compound and enhances low-temperature toughness. The modified ultra-high molecular weight polyethylene powder dispersed in the matrix utilizes its low coefficient of friction and high wear resistance to bear the main external friction load, reducing matrix wear. Calcined kaolin is used as a reinforcing filler to increase the tensile stress of the rubber compound, and the calcination treatment reduces adsorbed water and organic impurities, thus reducing odor sources. A peroxide crosslinking system is used instead of the traditional sulfur vulcanization system, avoiding the odor generated by the decomposition of thioether bonds, meeting the requirements of low odor and low volatile organic compounds in the cab. This technical solution achieves a unity of high wear resistance, excellent anti-slip properties, and low odor characteristics.

[0012] Preferably, the ethylene unit content of the EPDM rubber is 65%-70%; the metallocene polyolefin elastomer is an ethylene-octene copolymer with a density of 0.860 g / cm³. 3 -0.870g / cm 3 The first peroxide crosslinking agent is bis-tert-butylperoxyisopropylbenzene, and the second peroxide crosslinking agent is tert-butyl peroxide-2-ethylhexanoate.

[0013] By employing the above technical solutions, EPDM rubber with high ethylene content exhibits higher raw rubber strength and filler powder capacity. Low-density ethylene-octene copolymers show good compatibility with EPDM rubber, forming a co-continuous structure in the blend, which can hinder microcrack propagation. A gradient crosslinking system is constructed using bis(tert-butylperoxyisopropylbenzene) and tert-butyl peroxide-2-ethylhexanoate, which have different decomposition temperatures. The lower decomposition temperature of tert-butyl peroxide-2-ethylhexanoate initiates the interfacial pre-reaction, while the higher decomposition temperature of bis(tert-butylperoxyisopropylbenzene) enables deep matrix crosslinking, achieving a staged, controlled reaction.

[0014] Preferably, the modified ultra-high molecular weight polyethylene powder is prepared from the following components in parts by weight: ultra-high molecular weight polyethylene micro powder: 100 parts; reactive liquid polyolefin: 50-85 parts; vinyltrimethoxysilane: 3-5 parts.

[0015] By adopting the above technical solution, the problem of poor adhesion between ultra-high molecular weight polyethylene (UHMWPE) and the rubber matrix due to surface inertness was solved. The modification mechanism and process are as follows: 1. Physical wetting and modulus transition: During mixing, reactive liquid polyolefin coats the surface of UHMWPE micropowder and penetrates into the amorphous regions of the powder surface, forming a physical entanglement layer. This flexible transition layer improves the interfacial compatibility between high-modulus plastic particles and low-modulus rubber matrix, alleviating stress concentration at the interface. 2. Chemical grafting to introduce active sites: Vinyltrimethoxysilane, under thermomechanical force, binds to the surface of UHMWPE powder through hydrolysis condensation or free radical grafting reaction, thereby introducing reactive vinyl double bonds onto the powder surface. 3. Interfacial co-crosslinking: During the vulcanization process of the floor mat, the double bonds of vinyl and liquid polyolefin introduced on the powder surface and the double bonds of the EPDM rubber matrix undergo a copolymerization reaction under the action of a peroxide initiator, forming chemical bonds. This synergistic effect of chemical bonding and physical entanglement enhances the interfacial bonding strength and prevents ultra-high molecular weight polyethylene particles from peeling off from the rubber matrix under frictional shear force.

[0016] Preferably, the reactive liquid polyolefin is selected from liquid ethylene propylene diene monomer (EPDM) rubber or high-vinyl liquid polybutadiene.

[0017] By adopting the above technical solution, the molecular chain structure of liquid EPDM rubber is similar to that of the matrix rubber, and it has thermodynamic compatibility, which helps to carry silane coupling agents to spread on the powder surface; the high vinyl liquid polybutadiene contains a high proportion of side-attached vinyl groups, which has high reactivity and can improve the crosslinking density of the interface.

[0018] Preferably, the crosslinking aid is triallyl isocyanurate.

[0019] By adopting the above technical solution, triallyl isocyanurate, as a co-crosslinking agent, can inhibit the breakage of the rubber backbone during the peroxide vulcanization process and improve the crosslinking efficiency; at the same time, the three allyl functional groups it contains can form a dense three-dimensional network structure with vinyl silane and rubber double bonds in the system, thereby improving the heat resistance and compression set resistance of the material.

[0020] A method for preparing a wear-resistant cab floor mat includes the following steps:

[0021] (1) Premix EPDM rubber and metallocene polyolefin elastomer in a mixer to obtain a premixed rubber compound; (2) Add modified ultra-high molecular weight polyethylene powder, nano zinc oxide, stearic acid and antioxidant to the premixed rubber compound and mix it. Then add calcined kaolin and mix it to a specified temperature before discharging to obtain a compounded rubber compound; (3) Transfer the compounded rubber compound to a two-roll mill, add crosslinking aid, first peroxide crosslinking agent and second peroxide crosslinking agent, and after thinning and sheeting, obtain a rubber sheet to be vulcanized; (4) Vulcanize the rubber sheet to be vulcanized in a first flat vulcanizing mill to pre-crosslink and lock the interface of ultra-high molecular weight polyethylene particles to obtain a shaped semi-finished product; (5) Transfer the shaped semi-finished product to a second flat vulcanizing mill to vulcanize in a second stage to deeply vulcanize the rubber sheet matrix to obtain the wear-resistant cab floor mat.

[0022] By employing the above technical solution, this method utilizes a segmented mixing process to prioritize the blending morphology of EPDM rubber and metallocene polyolefin elastomer, forming a uniform polymer matrix. Subsequently, modified powders and inorganic fillers are added, reducing the interference of fillers on polymer compatibility. A low-temperature vulcanization process using an open mill avoids early decomposition (scorching) of the dual peroxide system during the mixing stage. The core of this method lies in establishing a graded vulcanization control system, utilizing the differences in decomposition temperatures of different peroxides to regulate the sequence of interfacial reactions and matrix crosslinking, ensuring the orderly formation of the composite material's microstructure.

[0023] Preferably, the process control in steps (1) and (2) is as follows:

[0024] In step (1), the preheating temperature of the internal mixer cavity is 85℃-95℃, and the mixing time is 50-70 seconds; in step (2), the calcined kaolin is added in two batches, and the discharge temperature is controlled at 112℃-118℃. The modified ultra-high molecular weight polyethylene powder is prepared in advance by the following method: S1, ultra-high molecular weight polyethylene micro powder is stirred at high speed under heating conditions of 80℃-85℃ to obtain preheated powder; S2, reactive liquid polyolefin and vinyltrimethoxysilane are mixed evenly at 50℃-60℃ to obtain homogeneous modified liquid; S3, the stirring speed is increased, and the homogeneous modified liquid is atomized and sprayed into the preheated powder. After spraying, high-speed stirring is continued, and the powder is cooled to obtain the final product.

[0025] By adopting the above technical solutions, the mixing temperature and discharge temperature are controlled below 118℃, effectively preventing the active groups on the surface of the modified powder from undergoing thermal cross-linking during the mixing stage and preserving their reactivity. The step-by-step addition process of calcined kaolin improves the wetting and dispersion effect of the filler in the rubber compound and reduces agglomeration. In the pre-preparation of the modified powder, heating and high-speed stirring remove adsorbed water from the powder surface and fluidize the powder particles. Combined with the atomization spraying process, uniform coating of liquid modifier on the micron-sized powder surface is achieved, providing uniform binding sites for subsequent interfacial reactions.

[0026] Preferably, in step (4), the conditions for the first stage of vulcanization are: temperature 120℃-130℃, pressure 14MPa-16MPa, and time 120 seconds-180 seconds. In step (5), the conditions for the second stage of vulcanization are: temperature 165℃-175℃, pressure 14MPa-16MPa, and time 480 seconds-600 seconds; and the transfer time from opening the mold in step (4) to closing the mold and applying pressure in step (5) is controlled within 25 seconds.

[0027] By adopting the above technical solution, a gradient sulfidation mechanism based on the difference in peroxide half-life was constructed:

[0028] The first stage (interfacial pre-reaction and shaping): Within a temperature range of 120℃ to 130℃, the second peroxide crosslinking agent (tert-butyl peroxide-2-ethylhexanoate), which has a relatively low decomposition temperature, rapidly decomposes to generate free radicals, preferentially initiating a grafting reaction between the active vinyl groups on the modified powder surface and the rubber molecular chains. This process establishes interfacial chemical bonds without causing overall curing of the rubber matrix, anchoring the hard particles in the matrix and completing the preliminary shaping of the semi-finished product.

[0029] The second stage (deep cross-linking of the matrix): In the temperature range of 165℃ to 175℃, the first peroxide cross-linking agent (di-tert-butylperoxyisopropylbenzene), which has a high decomposition temperature, decomposes in large quantities, triggering the cross-linking reaction of the EPDM rubber matrix, forming a dense three-dimensional network structure, and giving the floor mat the final mechanical properties and heat resistance.

[0030] Thermal transfer control: The transfer time between the two vulcanization stages is controlled within 25 seconds, maintaining the thermal motion state of the polymer chain segments and avoiding interfacial stress shrinkage and decreased interlayer bonding due to temperature drop.

[0031] This invention provides a wear-resistant floor mat for a driver's cab and its preparation method. It has the following beneficial effects:

[0032] 1. This invention introduces ultra-high molecular weight polyethylene powder modified with liquid polyolefin and silane coupling agent into EPDM rubber, utilizing the double bond reaction between components to form chemical bonds at the phase interface. This structure enhances interfacial bonding, preventing particles from detaching under frictional shearing, significantly improving the wear resistance of cab floor mats while solving the problems of flaking and localized wear caused by poor interfacial bonding in traditional materials.

[0033] 2. This invention eliminates the odor generated by the decomposition of sulfide bonds by using a dual peroxide system instead of the traditional sulfur sulfidation system; combined with calcined kaolin treated at high temperatures, it effectively removes organic impurities and volatiles from the filler. This formulation system reduces the content of volatile organic compounds at the source, enabling the resulting cab floor mat to meet the stringent standards for low odor and air quality in enclosed driving spaces.

[0034] 3. This invention improves the processing flowability and low-temperature toughness of the rubber compound by introducing a metallocene polyolefin elastomer and EPDM rubber to construct a co-continuous phase structure. This soft-hard matrix design ensures high wear resistance for the cab floor mat while retaining the excellent anti-slip properties and elastic feel of the rubber material, overcoming the shortcomings of traditional technologies that simply increase hardness, leading to a decrease in anti-slip performance. Attached Figure Description

[0035] Figure 1 These are comparison diagrams of the mechanical properties of the present invention; wherein, (a) is a comparison diagram of right-angle tear strength; (b) is a comparison diagram of tensile strength; and (c) is a comparison diagram of elongation at break.

[0036] Figure 2 This is a comparison chart of the hot air aging performance of the present invention; wherein, (a) is a comparison chart of the reduction rate of tensile strength after aging; and (b) is a comparison chart of the reduction rate of elongation at break after aging.

[0037] Figure 3 This is a comparison chart of the combustion speed of the present invention. Detailed Implementation

[0038] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0040] Ethylene propylene diene monomer (EPDM) rubber is made from ethylene-propylene-diolefin terpolymer, CAS number 25038-36-2, with ethylene unit content of 65% to 70%, ENB content of 4.5% to 5.5%, and Mooney viscosity ML(1+4)@125℃ of 50 to 60.

[0041] The metallocene polyolefin elastomer (POE) is an ethylene-octene copolymer, CAS number 26221-73-8, with a 1-octene content of 20% to 35% and a density of 0.860 g / cm³. 3 Up to 0.870 g / cm 3 The melt flow rate (190℃, 2.16kg) is 0.5g / 10min to 1.0g / 10min.

[0042] The ultra-high molecular weight polyethylene (UHMWPE) micro powder is made from linear ethylene homopolymer, with CAS number 9002-88-4, a viscosity-average molecular weight greater than 3 million, an average particle size of 74μm to 100μm, and a melting point of 133℃ to 138℃.

[0043] The reactive liquid polyolefin is selected from low molecular weight liquid ethylene propylene diene monomer (EPDM) rubber, CAS number 25038-36-2, with a number average molecular weight (Mn) of 2000 to 5000, an iodine value of 15 g / 100 g to 25 g / 100 g, and a Brookfield viscosity of 10 Pa·s to 20 Pa·s at 75°C; or high vinyl liquid polybutadiene, CAS number 9003-17-2, with a number average molecular weight (Mn) of 2000 to 4000 and a 1,2-vinyl structure content greater than 85%.

[0044] Other functional additives are commercially available industrial-grade products, including tert-butyl peroxide-2-ethylhexanoate (TBEC, CAS No. 3006-82-4), bis-tert-butylperoxyisopropylbenzene (BIBP, CAS No. 25155-25-3), triallyl isocyanurate (TAIC, CAS No. 1025-15-6), vinyltrimethoxysilane (CAS No. 2768-02-7), 2-mercaptobenzimidazole (antioxidant MB, CAS No. 583-39-1), calcined kaolin (CAS No. 92704-41-1, modified with vinylsilane, particle size 2μm to 4μm), nano zinc oxide (CAS No. 1314-13-2), and stearic acid (CAS No. 57-11-4).

[0045] Preparation Example 1: This preparation example provides a method for preparing modified ultra-high molecular weight polyethylene powder (denoted as modified powder A), including the following steps:

[0046] (1) Add 100 parts by weight of ultra-high molecular weight polyethylene (UHMWPE) micro powder to a high-speed mixer with a heating jacket, set the heating temperature to 85°C, and stir at 400 rpm for 5 minutes to obtain surface-activated and moisture-removed preheated UHMWPE powder.

[0047] (2) Add 70 parts by weight of reactive liquid polyolefin (liquid ethylene propylene diene rubber) and 4 parts by weight of vinyltrimethoxysilane into an independent stirring container, and mix at 200 rpm for 3 minutes at 50°C to 60°C to obtain a homogeneous modified liquid.

[0048] (3) Increase the speed of the high-speed mixer to 1600 rpm, and spray the homogeneous modified liquid obtained in step (2) into the preheated UHMWPE powder obtained in step (1) at a rate of 20 parts by weight / minute through the atomizing nozzle. After spraying, continue to stir at high speed for 6 minutes, discharge the material and cool it naturally to room temperature to obtain modified powder A in the form of wet sand.

[0049] Preparation Example 2: This preparation example provides a method for preparing modified ultra-high molecular weight polyethylene powder (denoted as modified powder B), including the following steps:

[0050] (1) Add 100 parts by weight of ultra-high molecular weight polyethylene (UHMWPE) micro powder to a high-speed mixer with a heating jacket, set the heating temperature to 80°C, and stir at 350 rpm for 4 minutes to obtain surface-activated and moisture-removed preheated UHMWPE powder.

[0051] (2) Add 60 parts by weight of reactive liquid polyolefin (high vinyl liquid polybutadiene) and 3 parts by weight of vinyltrimethoxysilane into an independent stirring container, and mix at 200 rpm for 2 minutes at 50°C to 60°C to obtain a homogeneous modified liquid.

[0052] (3) Increase the speed of the high-speed mixer to 1500 rpm, and spray the homogeneous modified liquid obtained in step (2) into the preheated UHMWPE powder obtained in step (1) at a rate of 15 parts by weight / minute through the atomizing nozzle. After spraying, continue to stir at high speed for 5 minutes, discharge the material and cool it naturally to room temperature to obtain modified powder B in the form of wet sand.

[0053] Preparation Example 3: This preparation example provides a method for preparing modified ultra-high molecular weight polyethylene powder (denoted as modified powder C), including the following steps:

[0054] (1) Add 100 parts by weight of ultra-high molecular weight polyethylene (UHMWPE) micro powder to a high-speed mixer with a heating jacket, set the heating temperature to 82°C, and stir at 400 rpm for 4 minutes to obtain surface-activated and moisture-removed preheated UHMWPE powder.

[0055] (2) Add 50 parts by weight of reactive liquid polyolefin (liquid ethylene propylene diene rubber) and 3 parts by weight of vinyltrimethoxysilane into an independent stirring container, and mix at 200 rpm for 2 minutes at 50°C to 60°C to obtain a homogeneous modified liquid.

[0056] (3) Increase the speed of the high-speed mixer to 1500 rpm, and spray the homogeneous modified liquid obtained in step (2) into the preheated UHMWPE powder obtained in step (1) at a rate of 15 parts by weight / minute through the atomizing nozzle. After spraying, continue to stir at high speed for 5 minutes, discharge the material and cool it naturally to room temperature to obtain modified powder C in the form of wet sand.

[0057] Preparation Example 4: This preparation example provides a method for preparing modified ultra-high molecular weight polyethylene powder (denoted as modified powder D), including the following steps:

[0058] (1) Add 100 parts by weight of ultra-high molecular weight polyethylene (UHMWPE) micro powder to a high-speed mixer with a heating jacket, set the heating temperature to 85°C, and stir at 450 rpm for 5 minutes to obtain surface-activated and moisture-removed preheated UHMWPE powder.

[0059] (2) Add 85 parts by weight of reactive liquid polyolefin (liquid ethylene propylene diene rubber) and 5 parts by weight of vinyltrimethoxysilane into an independent stirring container, and mix at 200 rpm for 3 minutes at 50°C to 60°C to obtain a homogeneous modified liquid.

[0060] (3) Increase the speed of the high-speed mixer to 1800 rpm, and spray the homogeneous modified liquid obtained in step (2) into the preheated UHMWPE powder obtained in step (1) at a rate of 20 parts by weight / minute through the atomizing nozzle. After spraying, continue to stir at high speed for 8 minutes, discharge the material and cool it naturally to room temperature to obtain modified powder D in the form of wet sand.

[0061] Example 1: This example provides a method for preparing a wear-resistant cab floor mat, including the following steps:

[0062] (1) Preheat the cavity of the internal mixer to 90°C, set the rotor speed to 60 rpm, set the pressure of the top bolt to 0.60 MPa, add 100 parts by weight of EPDM rubber and 25 parts by weight of metallocene polyolefin elastomer, mix for 60 seconds to obtain premixed rubber.

[0063] (2) Add 30 parts by weight of modified powder A prepared in Preparation Example 1, 4 parts by weight of nano zinc oxide, 0.8 parts by weight of stearic acid and 0.8 parts by weight of 2-mercaptobenzimidazole to the premixed rubber obtained in step (1), continue to mix for 100 seconds, and then add a total of 45 parts by weight of calcined kaolin in two equal portions, with an interval of 40 seconds between each addition. When the temperature of the rubber reaches 115°C, discharge the rubber to obtain the mixed rubber.

[0064] (3) Transfer the compound obtained in step (2) to the open mill, control the roller surface temperature to 45°C, add 1.8 parts by weight of triallyl isocyanurate, 2.2 parts by weight of di-tert-butylperoxyisopropylbenzene and 0.6 parts by weight of tert-butyl peroxide-2-ethylhexanoate, cut the left and right blades 4 times each and make a triangular wrapping thin pass 5 times, and cut the sheet to obtain a 6 mm thick rubber sheet to be vulcanized, and let it stand for 10 hours;

[0065] (4) Place the film to be vulcanized obtained in step (3) into the mold of the first flat vulcanizing machine at a temperature of 125°C, close the mold with a pressure of 15.0 MPa for 150 seconds to pre-crosslink and lock the interface of the ultra-high molecular weight polyethylene particles in the film, and open the mold to obtain the shaped semi-finished product.

[0066] (5) Transfer the shaped semi-finished product obtained in step (4) to the mold of the second flat vulcanizing machine at a temperature of 170°C within 23 seconds, close the mold with a pressure of 15.0 MPa for 540 seconds to make the film substrate deeply vulcanized, open the mold and trim the flash to obtain the wear-resistant cab floor mat.

[0067] Example 2: This example provides a method for preparing a wear-resistant cab floor mat, including the following steps:

[0068] (1) Preheat the cavity of the internal mixer to 95°C, set the rotor speed to 65 rpm, set the pressure of the top bolt to 0.70 MPa, add 100 parts by weight of EPDM rubber and 20 parts by weight of metallocene polyolefin elastomer, mix for 70 seconds to obtain premixed rubber.

[0069] (2) Add 35 parts by weight of modified powder A prepared in Preparation Example 1, 4 parts by weight of nano zinc oxide, 0.8 parts by weight of stearic acid and 0.8 parts by weight of 2-mercaptobenzimidazole to the premixed rubber obtained in step (1), continue to mix for 110 seconds, and then add a total of 40 parts by weight of calcined kaolin in two equal portions, with an interval of 45 seconds between each addition. When the temperature of the rubber reaches 118°C, discharge the rubber to obtain the mixed rubber.

[0070] (3) Transfer the compound obtained in step (2) to the open mill, control the roller surface temperature to 50°C, add 2.0 parts by weight of triallyl isocyanurate, 2.5 parts by weight of di-tert-butylperoxyisopropylbenzene and 0.7 parts by weight of tert-butyl peroxide-2-ethylhexanoate, cut the left and right blades 4 times each and make a triangular wrapping 6 times to get a 6 mm thick rubber sheet to be vulcanized, and let it stand for 12 hours;

[0071] (4) Place the film to be vulcanized obtained in step (3) into the mold of the first flat vulcanizing machine at a temperature of 130°C, and pressurize it with a pressure of 16.0 MPa for 180 seconds to make the interface of ultra-high molecular weight polyethylene particles in the film pre-crosslinked and locked, and open the mold to obtain the shaped semi-finished product.

[0072] (5) Transfer the shaped semi-finished product obtained in step (4) to the mold of the second flat vulcanizing machine at a temperature of 175°C within 25 seconds, close the mold with a pressure of 16.0 MPa for 600 seconds to make the film substrate deeply vulcanized, open the mold and trim the flash to obtain the wear-resistant cab floor mat.

[0073] Example 3: This example provides a method for preparing a wear-resistant cab floor mat, including the following steps:

[0074] (1) Preheat the cavity of the internal mixer to 85°C, set the rotor speed to 55 rpm, set the pressure of the top bolt to 0.50 MPa, add 100 parts by weight of EPDM rubber and 30 parts by weight of metallocene polyolefin elastomer, mix for 50 seconds to obtain premixed rubber.

[0075] (2) Add 25 parts by weight of modified powder C prepared in Preparation Example 3, 3 parts by weight of nano zinc oxide, 0.5 parts by weight of stearic acid and 0.5 parts by weight of 2-mercaptobenzimidazole to the premixed rubber obtained in step (1), continue to mix for 90 seconds, and then add a total of 50 parts by weight of calcined kaolin in two equal portions, with an interval of 30 seconds between each addition. When the rubber temperature reaches 112°C, discharge the rubber to obtain the mixed rubber.

[0076] (3) Transfer the compound obtained in step (2) to the open mill, control the roller surface temperature to 40°C, add 1.5 parts by weight of triallyl isocyanurate, 2.0 parts by weight of di-tert-butylperoxyisopropylbenzene and 0.5 parts by weight of tert-butyl peroxide-2-ethylhexanoate, cut the left and right blades 3 times each and make a triangular wrapping 4 times to get a 6 mm thick rubber sheet to be vulcanized, and let it stand for 8 hours;

[0077] (4) Place the film to be vulcanized obtained in step (3) into the mold of the first flat vulcanizing machine at a temperature of 120°C, close the mold with a pressure of 14.0 MPa for 120 seconds to cause pre-crosslinking and locking at the interface of ultra-high molecular weight polyethylene particles in the film, and open the mold to obtain the shaped semi-finished product.

[0078] (5) Transfer the shaped semi-finished product obtained in step (4) to the mold of the second flat vulcanizing machine at a temperature of 165°C within 20 seconds, close the mold with a pressure of 14.0 MPa for 480 seconds to make the film substrate deeply vulcanized, open the mold and trim the flash to obtain the wear-resistant cab floor mat.

[0079] Example 4: This example provides a method for preparing a wear-resistant cab floor mat, including the following steps:

[0080] (1) Preheat the cavity of the internal mixer to 88°C, set the rotor speed to 58 rpm, set the pressure of the top plug to 0.55 MPa, add 100 parts by weight of EPDM rubber and 25 parts by weight of metallocene polyolefin elastomer, mix for 55 seconds to obtain premixed rubber.

[0081] (2) Add 30 parts by weight of modified powder B prepared in Preparation Example 2, 4 parts by weight of nano zinc oxide, 0.8 parts by weight of stearic acid and 0.8 parts by weight of 2-mercaptobenzimidazole to the premixed rubber obtained in step (1), continue to mix for 95 seconds, and then add a total of 45 parts by weight of calcined kaolin in two equal portions, with an interval of 35 seconds between each addition. When the temperature of the rubber reaches 114°C, discharge the rubber to obtain the mixed rubber.

[0082] (3) Transfer the compound obtained in step (2) to the open mill, control the roller surface temperature to 42°C, add 1.8 parts by weight of triallyl isocyanurate, 2.2 parts by weight of di-tert-butylperoxyisopropylbenzene and 0.8 parts by weight of tert-butyl peroxide-2-ethylhexanoate, cut the left and right blades 4 times each and make a triangular wrapping thin pass 5 times, and cut the sheet to obtain a 6 mm thick rubber sheet to be vulcanized, and let it stand for 9 hours;

[0083] (4) Place the film to be vulcanized obtained in step (3) into the mold of the first flat vulcanizing machine at a temperature of 122°C, and close the mold with a pressure of 14.5 MPa for 135 seconds to make the interface of ultra-high molecular weight polyethylene particles in the film undergo rapid pre-crosslinking and locking, and open the mold to obtain the shaped semi-finished product.

[0084] (5) Transfer the shaped semi-finished product obtained in step (4) to the mold of the second flat vulcanizing machine at a temperature of 168°C within 22 seconds, close the mold with a pressure of 14.5 MPa for 510 seconds to make the film substrate deeply vulcanized, open the mold and trim the flash to obtain the wear-resistant cab floor mat.

[0085] Example 5: This example provides a method for preparing a wear-resistant cab floor mat, including the following steps:

[0086] (1) Preheat the cavity of the internal mixer to 92°C, set the rotor speed to 62 rpm, set the pressure of the top bolt to 0.65 MPa, add 100 parts by weight of EPDM rubber and 25 parts by weight of metallocene polyolefin elastomer, mix for 65 seconds to obtain premixed rubber.

[0087] (2) Add 30 parts by weight of modified powder D prepared in Preparation Example 4, 4 parts by weight of nano zinc oxide, 0.8 parts by weight of stearic acid and 0.8 parts by weight of 2-mercaptobenzimidazole to the premixed rubber obtained in step (1), continue to mix for 105 seconds, and then add a total of 45 parts by weight of calcined kaolin in two equal portions, with an interval of 42 seconds between each addition. When the temperature of the rubber reaches 116°C, discharge the rubber to obtain the mixed rubber.

[0088] (3) Transfer the compound obtained in step (2) to the open mill, control the roller surface temperature to 48°C, add 1.8 parts by weight of triallyl isocyanurate, 2.2 parts by weight of di-tert-butylperoxyisopropylbenzene and 0.6 parts by weight of tert-butyl peroxide-2-ethylhexanoate, cut the left and right blades 4 times each and make a triangular wrapping 5 times to get a 6 mm thick rubber sheet to be vulcanized, and let it stand for 11 hours;

[0089] (4) Place the film to be vulcanized obtained in step (3) into the mold of the first flat vulcanizing machine at a temperature of 128°C, and pressurize it with a pressure of 15.5 MPa for 165 seconds to make the interface of ultra-high molecular weight polyethylene particles in the film pre-crosslinked and locked, and open the mold to obtain the shaped semi-finished product.

[0090] (5) Transfer the shaped semi-finished product obtained in step (4) to the mold of the second flat vulcanizing machine at a temperature of 172°C within 24 seconds, close the mold with a pressure of 15.5 MPa for 570 seconds to make the film substrate deeply vulcanized, open the mold and trim the flash to obtain the wear-resistant cab floor mat.

[0091] Comparative Example 1: Compared with Example 1, the difference is that in step (2) of preparation Example 1, an equal part by weight of paraffin oil (CAS No.: 8012-95-1) was used to replace the reactive liquid polyolefin (liquid EPDM rubber), and all other aspects were the same.

[0092] Comparative Example 2: Compared with Example 1, the difference is that tert-butyl peroxide-2-ethylhexanoate was not added in step (3), and the mold temperature in step (4) was adjusted to 170°C (i.e., the 125°C pre-locking was canceled, and vulcanization was carried out directly at high temperature), while the rest were the same.

[0093] Comparative Example 3: Compared with Example 1, the difference is that the 125°C pre-crosslinking locking process described in step (4) is cancelled, and the film to be vulcanized obtained in step (3) is directly placed into a mold at 170°C for one-time vulcanization. The pressure time is extended to 690 seconds, and the rest are the same.

[0094] Comparative Example 4: Compared with Example 1, the difference is that in step (2), the modified powder A obtained in Preparation Example 1 is not used. Instead, 17.2 parts by weight of unmodified UHMWPE micro powder, 12.1 parts by weight of liquid EPDM rubber and 0.7 parts by weight of vinyltrimethoxysilane (i.e., the effective content of each component in 30 parts of modified powder A) are directly added to the internal mixer and mixed with the premixed rubber compound. The rest are the same.

[0095] Test Example 1:

[0096] 1. Experimental Instructions and Procedures

[0097] This test example selects the final products prepared by Example 1, Comparative Example 1 and Comparative Example 4, and wear-resistant cab floor mat (specification: 5mm thick sheet) as the test sample.

[0098] (1) Sample preparation and conditioning

[0099] From the vulcanized rubber sheets (floor mats) prepared in the above examples, cut the test samples using a standard cutter.

[0100] Tear strength test specimen: Use a right-angle cutter to cut a specimen to a right angle shape conforming to GB / T 529-2008, with a cut depth of 1.0 mm ± 0.2 mm and a thickness ground to 2.0 mm ± 0.2 mm.

[0101] Tensile property test specimens: Dumbbell-shaped specimens conforming to GB / T 528-2009 were prepared using a dumbbell-shaped cutter (Type I). The narrow parallel section was 6.0 mm wide, the total length was 115 mm, and the thickness was ground to 2.0 mm ± 0.2 mm.

[0102] Odor-based test samples: Cut square test blocks with dimensions of 100mm×100mm×5mm directly.

[0103] Aging performance test specimen: same as tensile performance test specimen.

[0104] Before testing, all cut samples were conditioned for 24 hours in a standard laboratory environment with a temperature of 23±2℃ and a relative humidity of 50±5%.

[0105] (2) Tear strength test

[0106] The procedure is performed according to GB / T 529-2008 standard. Measure the actual thickness of the specimen at the notch (accurate to 0.01 mm). Clamp the specimen in the upper and lower grips of the electronic tensile testing machine, keeping the specimen perpendicular, with the notch located on the line connecting the centers of the two grips. Start the testing machine and apply tension at a tensile speed of 500 mm / min until the specimen is completely torn. Record the maximum force (N) during the fracture process and calculate the fracture value according to the formula... Calculate the tear strength (where: For tear strength, To maximize force, (This refers to the sample thickness). Five samples were tested in each group, and the arithmetic mean was taken.

[0107] (3) Tensile property test

[0108] Performed according to GB / T 528-2009 standard. Draw two markings on the narrow parallel section of the specimen, with a gauge length of... The gauge length is 25 mm. Measure the thickness and width within the gauge length. Symmetrically clamp the specimen into the tensile testing machine fixture and stretch it at a speed of 500 mm / min. Record the maximum force at fracture and the distance between the gauge marks at the moment of fracture. Calculation formula: Tensile strength (TS): (In the formula: This is the maximum force value, in N; Width of the parallel section, in mm; Elongation at break (Eb) (for thickness, in mm): (In the formula: The gauge length at break, in mm; (Initial gauge length, unit: mm)

[0109] (4) Odor evaluation

[0110] The procedure was performed according to VDA 270 (Determination of Odor Characteristics of Automotive Interior Materials) standard, variant C3 (3-liter glass bottle method). Odorless glass desiccators were cleaned and dried. The sample was suspended inside the bottle, the cap was tightened, and the bottle was heated in an oven at 80℃±2℃ for 2 hours. After heating, the sample was removed and cooled to 60℃ for hot olfaction (or cooled to room temperature for room temperature olfaction; this experiment uniformly used olfaction after cooling to 23℃). Seven evaluators with normal olfaction were selected to open the bottle caps and smell the sample sequentially, using the VDA 270 6-point scale (Level 1: Odorless; Level 2: Detectable but not interfering; Level 3: Noticeably detectable but not interfering; Level 4: Interfering odor; Level 5: Strongly interfering odor; Level 6: Unbearable). The highest and lowest scores were removed, and the arithmetic mean of the remaining five scores was taken.

[0111] (5) Hot air aging test:

[0112] The aging process was conducted according to GB / T 3512 standard. The samples were suspended in a forced-ventilation hot air aging chamber, set at 125℃ for 70 hours. After aging, the samples were removed and placed under standard conditions for 16 hours. The hardness, tensile strength, and elongation at break were measured before and after aging. Calculation formula:

[0113] Changes in hardness after aging:

[0114] (In the formula: Hardness after aging; (This represents the hardness before aging; the result should be rounded to the nearest integer).

[0115] Reduction in tensile strength after aging:

[0116] (In the formula: Tensile strength before aging; (Tensile strength after aging).

[0117] Reduction in elongation at break after aging:

[0118] (In the formula: Elongation before aging; (Elongation after aging).

[0119] 2. Experimental results data (see Table 1)

[0120] Table 1: Summary of Interfacial Bonding Strength and Reaction Stability Test Data

[0121] Test Project unit Example 1 Comparative Example 1 Comparative Example 4 Tear strength (right angle) KN / m 48.52 36.47 31.54 Tensile strength MPa 15.24 11.53 10.82 Elongation at break % 460 390 360 Odor rating class 2.0 3.5 2.4 Changes in hardness after aging Shore A hardness (HA) +3 +6 +4 Reduction in tensile strength after aging % 8.5 22.4 14.2 Reduction in elongation at break after aging % 11.2 24.1 18.6

[0122] 3. Results Analysis and Conclusions

[0123] Table 1 shows that the tear strength of Example 1 is 48.52 KN / m, which is higher than that of Comparative Example 1 (36.47 KN / m) and Comparative Example 4 (31.54 KN / m). Example 1 uses reactive liquid EPDM rubber as a medium. During vulcanization, under the action of the initiator, the vinyl or double bond structure of the liquid rubber co-crosslinks with the surface of UHMWPE particles and the EPDM matrix, forming a chemically bonded interface, which improves the stress transfer ability of the material during tearing. Comparative Example 1 uses chemically inert paraffin oil, which only provides physical lubrication and filling for the powder. The UHMWPE and the matrix are physically adsorbed, resulting in weak interfacial bonding and easy interfacial slippage under stress. Comparative Example 4 did not undergo pre-wetting treatment. When the UHMWPE micropowder is mixed with the high-viscosity matrix, it is difficult to disperse sufficiently, easily forming agglomerates and causing stress concentration, resulting in the lowest tensile and tear strengths.

[0124] Regarding odor and aging resistance, Example 1 had an odor rating of 2.0 and a tensile strength reduction rate of 8.5% after hot air aging; while Comparative Example 1 had an odor rating of 3.5, a tensile strength reduction rate of 22.4% after aging, and a significant increase in hardness (+6HA). The difference lies in the fact that the reactive liquid polyolefin participated in the vulcanization reaction and was fixed within the cross-linked network, reducing the presence of free small molecules, thus exhibiting better thermal stability and lower odor. The paraffin oil in Comparative Example 1 did not participate in the chemical reaction and easily migrated to the surface and volatilized at high temperatures, leading to material volume shrinkage, increased hardness, and performance degradation. Simultaneously, the volatiles caused an increase in the odor rating.

[0125] In summary, pre-wetting modification of UHMWPE using reactive liquid polyolefins can improve the dispersion of micropowders in the matrix and enhance the mechanical properties, aging resistance, and environmental characteristics of the material by forming a chemical cross-linking interface.

[0126] Test Example 2:

[0127] 1. Experimental Instructions and Procedures

[0128] This test example selects the finished cab floor mats (specifications: 500mm×500mm×5mm) prepared in Example 1, Comparative Example 2 and Comparative Example 3 as test samples.

[0129] (1) Sample selection and site marking

[0130] Three floor mats were randomly selected from the finished products prepared by each group. Five fixed test positions were marked on the surface of each floor mat: the geometric center point and the area points 50 mm away from the four corner vertices, which were marked as test points 1 to 5.

[0131] (2) Hardness data collection and statistical analysis

[0132] Lay the floor mat flat on a rigid, level surface, ensuring there is no gap underneath. Following GB / T 531.1 standard, use a Shore A hardness tester to vertically press into each marked point, holding for 3 seconds before reading the value.

[0133] Average hardness: (In the formula: For the first Hardness readings at each measuring point; (This represents the total number of measurement points, which is 5 in this case).

[0134] Hardness standard deviation (SD): (In the formula: For the first Hardness readings at each measuring point; This represents the average hardness. This represents the total number of measurement points. This value reflects the dispersion of hardness distribution in different areas of the sample surface; a larger value indicates a more uneven mixing within the material.

[0135] (3) Statistics on product surface quality and defects

[0136] Under a standard light source of 1000 Lux, the observer visually inspects the sample from a distance of 50 cm, and then evaluates it by touch.

[0137] Surface sensory evaluation: Wearing cotton gloves, smoothly stroke the sample surface with 5N pressure and record the tactile characteristics (such as "smooth", "rough", "resistive", "blooming or powdering").

[0138] Number of protrusions with a diameter greater than 0.5 mm: Use a graduated magnifying glass to measure the visible particles on the surface and count the total number of protrusions or bubbles with a diameter greater than 0.5 mm on the surface of a single sample.

[0139] Overall judgment: If the sample surface is smooth and there are no defects with a diameter > 0.5 mm, it is judged as qualified; otherwise, it is unqualified.

[0140] (4) Thickness measurement and range calculation

[0141] The thickness values ​​of the above 5 marked points were measured using a digital thickness gauge with an accuracy of 0.01 mm.

[0142] Thickness variation: (In the formula: The maximum thickness value among the 5 measuring points; (This is the minimum thickness value among the five measuring points). This indicator reflects the stability of the rubber compound flow and the accuracy of the molding dimensions during vulcanization.

[0143] 2. Experimental results data (see Table 2)

[0144] Table 2: Data on the Influence of Process Parameters on Product Molding Quality and Uniformity

[0145] Test Project Statistics / Units Example 1 Comparative Example 2 Comparative Example 3 Hardness at test point 1 HA 61 55 58 Test point 2 hardness HA 61 63 57 Test point 3 hardness HA 60 54 62 Test point 4 hardness HA 62 59 56 Test point 5 hardness HA 61 65 63 Average hardness HA 61.0 59.2 59.2 Standard deviation of hardness (SD) - 0.71 4.82 3.11 Surface sensory evaluation - Smooth, without grainy texture Rough, grainy Flow marks were present in some areas. Number of protrusions with a diameter > 0.5mm 1 / sample 0 18 7 Thickness difference mm 0.06 0.35 0.22 Comprehensive judgment - qualified Unqualified Unqualified

[0146] 3. Results Analysis and Conclusions

[0147] Table 2 shows that the standard deviation of hardness for sample 1 was 0.71, the thickness range was 0.06 mm, and no defects larger than 0.5 mm in diameter were found on the surface. In contrast, the standard deviation of hardness for Comparative Example 2 reached 4.82, the thickness range increased to 0.35 mm, and 18 visible protrusions were present on the surface; the standard deviation of hardness for Comparative Example 3 was 3.11, and flow marks and 7 visible protrusions were present on the surface.

[0148] The physical mechanism underlying the data discrepancies lies in the matching of vulcanization kinetics and phase control. The melting point of UHMWPE is approximately 136°C. Example 1 employed a 125°C isothermal pre-vulcanization process, where the system temperature is below the melting point of UHMWPE. At this temperature, the TBEC initiator has a shorter half-life, enabling it to preferentially initiate local cross-linking reactions at the interface between the EPDM matrix and the modified powder. The cross-linked network formed in this stage restricts the thermal motion and volume expansion of UHMWPE particles in the subsequent high-temperature stages, preventing particle contact and aggregation.

[0149] Comparative Example 2 used only a high-temperature initiator and directly heated the vulcanization process. When the temperature reached above 136°C, the cross-linking network of the EPDM matrix was not effectively established, while the UHMWPE particles had already melted. Molten polyethylene droplets migrated and aggregated under shear force or thermal motion, and upon cooling, crystallized to form larger agglomerates. These agglomerates resulted in locally higher hardness (e.g., 65 HA at measuring point 5) and lower hardness in areas of low hardness (e.g., 54 HA at measuring point 3), macroscopically manifesting as a rough surface and "blooming" particles.

[0150] Although Comparative Example 3 used dual initiators, it did not establish a constant temperature platform of 125°C. Because rubber is a poor conductor of heat, direct heating resulted in a large temperature difference between the inside and outside of the product, and the excessively rapid heating rate caused the system temperature to exceed the melting point of UHMWPE before TBEC could fully induce the formation of the pre-crosslinked network. Some UHMWPE particles melted and flowed unconfined, causing localized phase separation and dimensional deformation (thickness difference of 0.22 mm).

[0151] In summary, pre-crosslinking and locking within a temperature range below the melting point of UHMWPE is a necessary process control measure to ensure uniform dispersion of UHMWPE microcrystals in the rubber matrix, eliminate surface defects, and obtain uniform mechanical properties.

[0152] Test Example 3:

[0153] 1. Experimental Instructions and Procedures

[0154] This test example selects the finished cab floor mats (specifications: 5mm thick sheet material) prepared in Examples 1 to 5 and Comparative Examples 1 to 4 as test samples. The focus is on examining the comprehensive performance of the materials under low temperature, ozone corrosion, light radiation, and combustion conditions.

[0155] (1) Brittleness temperature test (low temperature performance)

[0156] According to GB / T 1682-2014 standard, type B specimens (32.0mm × 6.0mm × 2.0mm) were cut using a punching machine. The specimens were clamped in the fixtures of a brittle temperature testing machine and immersed in a freezing medium prepared from ethanol and liquid nitrogen. The temperature was lowered starting from -30℃, and the specimens were subjected to a cantilever beam impact every 2℃ at an impact velocity of 2.0m / s.

[0157] Brittleness temperature determination: Observe whether visible cracks, fractures, or holes appear on the surface of the sample after impact. Statistically record the highest temperature at which 50% of the samples fail as the brittleness temperature of the material.

[0158] (2) Ozone resistance aging test

[0159] The specimens were prepared according to GB / T 7762-2014 standard. The specimens were stretched to 20% of their static strain rate and fixed in stainless steel clamps. They were then placed in an ozone aging test chamber, with the test conditions set as follows: temperature 40℃±1℃, ozone concentration 100±10pphm (high concentration accelerates aging). The specimens were removed after 72 hours of testing.

[0160] Crack grade determination: Observe the tensile surface of the sample using a 10x magnifying glass and grade it according to GB / T 11206 standard:

[0161] Grade 0: No cracks;

[0162] Level 1: Minor cracks are visible under a magnifying glass, but not to the naked eye;

[0163] Level 2: Cracks are clearly visible to the naked eye;

[0164] Level 3: The crack is deep and long (greater than 1 mm).

[0165] (3) Light aging test (xenon arc lamp method)

[0166] The procedure was performed according to GB / T 16422.2-2014 standard. The blackboard temperature was set at 63℃±3℃, relative humidity at (50±5)%, and irradiance at 0.51W / (m²). 2 •nm)@340nm. The operating mode adopts a cycle of continuous light exposure for 102 minutes and water spray for 18 minutes, with a cumulative test time of 1000 hours.

[0167] Photoaging and discoloration level determination: After the test, according to GB / T 250 standard, under D65 standard light source, the discoloration of the sample is compared with the gray scale and rated (level 1 represents severe discoloration, level 5 represents no discoloration).

[0168] (4) Combustion performance test

[0169] According to GB 8410-2006 "Combustion Characteristics of Automotive Interior Materials" standard, a rectangular specimen with dimensions of 100mm × 355mm × 5mm was cut. The specimen was horizontally clamped on a U-shaped bracket, and a gas lamp was lit with a flame height of 38mm. The flame was applied to the free end of the specimen for 15 seconds and then removed.

[0170] Data Records:

[0171] Combustion distance ( ): The length of the flame that spreads and causes damage to the sample surface, in mm.

[0172] Burning time ( ): The time it takes for the flame to burn that distance, in seconds.

[0173] Combustion phenomena: Observe and record whether there are drips, black smoke concentration and flame shape during the combustion process.

[0174] Combustion rate calculation: ; (where: (This refers to the burning rate, measured in mm / min; a lower value indicates better flame retardancy and safety).

[0175] 2. Experimental results data (see Table 3)

[0176] Table 3: Test data on comprehensive environmental adaptability and combustion performance

[0177] Group Brittleness temperature (°C) Ozone resistant (100pphm / 72h) Light aging resistance (1000h / gray card grade) Combustion rate (mm / min) Description of combustion phenomena Example 1 -53 Level 0 4-5 37.5 The flame is steady and there are no drips. Example 2 -52 Level 0 4-5 38.1 The flame is steady and there are no drips. Example 3 -48 Level 0 4-5 34.8 Small flame, prone to self-extinguishing Example 4 -51 Level 1 4 39.2 Surface microcracks, flame wisps of smoke Example 5 -55 Level 0 4 42.1 Burning continued without dripping. Comparative Example 1 -38 Level 2 3 72.4 The flames were large, the black smoke was thick, and there was dripping smoke. Comparative Example 2 -45 Level 1 4 48.3 Rapid localized combustion, surface micro-cracks Comparative Example 3 -47 Level 1 4 46.9 Unstable flame Comparative Example 4 -44 Level 1-2 3-4 56.1 It burns quickly and produces a lot of smoke.

[0178] 3. Results Analysis and Conclusions

[0179] The test results in Table 3 show that Example 1 achieved the best balance in all aspects of performance: its brittle temperature was as low as -53°C, and it exhibited excellent performance in terms of burning speed (37.5 mm / min) and aging resistance (ozone level 0, light aging level 4-5). In contrast, Comparative Example 1, which used a physical plasticizer, performed the worst, while other examples and comparative examples showed different performance patterns due to differences in formulation or process. The fundamental reason for these differences lies in the chemical properties of the modified medium and its microscopic binding state in the matrix.

[0180] The differences in low-temperature performance mainly depend on the bonding strength of the interface and the flexibility of the system. Examples 1 to 5 all used reactive liquid rubber, a medium that not only wets the UHMWPE micropowder but also co-crosslinks with the EPDM matrix during vulcanization. This chemically bonded interface effectively transfers stress during low-temperature shrinkage, preventing microcracks caused by interfacial peeling. In Example 5, with the increase in the amount of liquid rubber (corresponding to 85 parts of Preparation Example 4), the system's flexibility further increased, resulting in the lowest brittle temperature (-55°C). Conversely, in Example 3, due to the lower liquid rubber content in the modified powder (corresponding to 50 parts of Preparation Example 3), the low-temperature toughness decreased slightly (-48°C), but was still superior to the comparative example. Although paraffin oil was added to Comparative Example 1, the viscosity of paraffin oil increased dramatically at low temperatures and was inconsistent with the rubber shrinkage rate, easily forming voids at the interface. Comparative Example 4, lacking a liquid medium for transition, had poor bonding between UHMWPE and the matrix, resulting in lower cold resistance than the examples.

[0181] In terms of ozone and photo-aging resistance, the molecular structure of the modified medium plays a decisive role. Example 1 used a main-chain saturated liquid EPDM rubber, whose chemical structure is naturally inert to ozone and ultraviolet light, thus exhibiting optimal weather resistance (Level 0, no cracking). While the liquid rubber used in Example 4 (the high-vinyl liquid polybutadiene in Preparation Example 2) is also reactive, its molecular chain contains a certain amount of unsaturated double bonds. Under prolonged exposure to high-concentration ozone (100 pphm), these double bonds become weak points, leading to micro-cracks on the surface (Level 1). The failure mechanism of Comparative Example 1 is completely different. Paraffin oil, being a non-reactive small molecule, migrates to the material surface under heat and light (blooming). The precipitated oil film adsorbs dust and undergoes oxidation and discoloration (Gray Card Level 3). Simultaneously, the microporous channels left after oil precipitation accelerate the penetration of ozone into the material's interior, resulting in severe cracking (Level 2).

[0182] The impact of process control on environmental adaptability is also significant. Although Comparative Examples 2 and 3 used the same reactive media as the examples, the lack of a pre-vulcanization locking process led to partial melting and agglomeration of the UHMWPE powder at high temperatures. These agglomerates resulted in uneven stress distribution within the material, becoming inducing points for aging. Therefore, even with the same chemical formulation, their ozone resistance (Level 1) was inferior to that of Example 1 (Level 0) with a well-developed process.

[0183] Finally, in terms of combustion safety, reactive media exhibited significant flame-retardant advantages. Paraffin oil (Comparative Example 1), as a flammable small-molecule hydrocarbon, rapidly volatilizes and supports combustion when heated, resulting in extremely fast combustion accompanied by a large amount of black smoke and dripping. In contrast, the liquid rubber in the examples participated in the cross-linked network, restricting molecular movement during thermal decomposition and preventing the release of free matter, thus making combustion more prone to charring and self-extinguishing. It is worth noting that Example 3, due to its lower organic liquid rubber content, had the slowest combustion speed (34.8 mm / min), indicating that reducing the total amount of organic matter is beneficial to improving flame retardancy, but this comes at the cost of sacrificing some low-temperature performance, while Example 1 found the optimal balance between the two.

[0184] In summary, by using reactive liquid rubber with a saturated structure to replace traditional physical plasticizers, and in conjunction with a step-locking vulcanization process, the risk of small molecule migration can be eliminated at the molecular level, and interfacial bonding can be strengthened, thereby significantly improving the overall service performance of materials in extreme environments.

[0185] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A wear-resistant floor mat for a driver's cab, characterized in that, Made from the following ingredients in parts by weight: EPDM rubber: 100 parts; Metallocene polyolefin elastomer: 20-30 parts; Modified ultra-high molecular weight polyethylene powder: 25-35 parts; Calcinated kaolin: 40-50 parts; Nano zinc oxide: 3-4 parts; Stearic acid: 0.5-0.8 parts; Anti-aging agent: 0.5-0.8 parts; Crosslinking aid: 1.5-2.0 parts; First peroxide crosslinking agent: 2.0-2.5 parts; Second peroxide crosslinking agent: 0.5-0.8 parts.

2. The wear-resistant floor mat for a driver's cab according to claim 1, characterized in that, The ethylene unit content of the EPDM rubber is 65%-70%; The metallocene polyolefin elastomer is an ethylene-octene copolymer with a density of 0.860 g / cm³. 3 -0.870g / cm 3 ; The first peroxide crosslinking agent is bis-tert-butylperoxyisopropylbenzene, and the second peroxide crosslinking agent is tert-butyl peroxide-2-ethylhexanoate.

3. The wear-resistant floor mat for a driver's cab according to claim 1, characterized in that, The modified ultra-high molecular weight polyethylene powder is prepared from components comprising the following parts by weight: Ultra-high molecular weight polyethylene micro powder: 100 parts; Reactive liquid polyolefins: 50-85 parts; Vinyltrimethoxysilane: 3-5 parts.

4. The wear-resistant floor mat for a driver's cab according to claim 3, characterized in that, The reactive liquid polyolefin is selected from liquid ethylene propylene diene monomer (EPDM) rubber or high-vinyl liquid polybutadiene.

5. The wear-resistant floor mat for a driver's cab according to claim 1, characterized in that, The crosslinking aid is triallyl isocyanurate.

6. A method for preparing a wear-resistant cab floor mat, used to prepare a wear-resistant cab floor mat as described in any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Premix EPDM rubber and metallocene polyolefin elastomer in an internal mixer to obtain a premixed rubber compound; (2) Add modified ultra-high molecular weight polyethylene powder, nano zinc oxide, stearic acid and antioxidant to the premixed rubber compound and mix them. Then add calcined kaolin and mix until the specified temperature is reached before discharging the rubber compound to obtain the mixed rubber compound. (3) Transfer the mixed rubber compound to a two-roll mill, add crosslinking aid, first peroxide crosslinking agent and second peroxide crosslinking agent, and obtain the rubber sheet to be vulcanized after thinning and sheeting. (4) The film to be vulcanized is vulcanized in the first flat vulcanizing machine to pre-crosslink and lock the interface of ultra-high molecular weight polyethylene particles to obtain a shaped semi-finished product. (5) Transfer the shaped semi-finished product to the second flat vulcanizing machine for the second stage of vulcanization, so that the film substrate undergoes deep vulcanization, thus obtaining the wear-resistant cab floor mat.

7. The method for preparing a wear-resistant cab floor mat according to claim 6, characterized in that, The process control in steps (1) and (2) is as follows: In step (1), the preheating temperature of the internal mixer cavity is 85℃-95℃, and the mixing time is 50-70 seconds; In step (2), the calcined kaolin is added in equal amounts in two separate steps, and the discharge temperature is controlled at 112℃-118℃.

8. The method for preparing a wear-resistant cab floor mat according to claim 6, characterized in that, In step (4), the conditions for the first stage of vulcanization are: temperature 120℃-130℃, pressure 14MPa-16MPa, and time 120 seconds-180 seconds.

9. The method for preparing a wear-resistant cab floor mat according to claim 6, characterized in that, In step (5), the conditions for the second stage of vulcanization are: temperature 165℃-175℃, pressure 14MPa-16MPa, and time 480 seconds-600 seconds; and the transfer time from opening the mold in step (4) to closing the mold and applying pressure in step (5) is controlled within 25 seconds.

10. The method for preparing a wear-resistant cab floor mat according to claim 6, characterized in that, In step (2), the modified ultra-high molecular weight polyethylene powder is prepared in advance by the following method: S1. The ultra-high molecular weight polyethylene micro powder is stirred at high speed under heating conditions of 80℃-85℃ to obtain preheated powder. S2. The reactive liquid polyolefin and vinyltrimethoxysilane are mixed evenly at 50℃-60℃ to obtain a homogeneous modified liquid; S3. Increase the stirring speed and atomize the homogeneous modified liquid into the preheated powder. Continue stirring after spraying and cool to obtain the final product.

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