Low-temperature-resistant automotive interior leather

Abstract

The invention provides low-temperature-resistant automotive interior leather which comprises a polyolefin base material layer, the polyolefin base material layer comprises a compact layer, the compact layer is composed of a polyolefin composition and an auxiliary agent, the auxiliary agent is dispersed in the polyolefin composition, the polyolefin composition is composed of an ethylene-alpha olefin copolymer serving as a continuous phase and ethylene propylene diene monomer serving as a dispersed phase, and the polyolefin base material layer comprises a low-temperature-resistant layer and a low-temperature-resistant layer. The compact layer has the crosslinking degree of more than or equal to 30%, the melting point of the ethylene-alpha olefin copolymer is less than or equal to 70 DEG C, the Mooney viscosity of the ethylene propylene diene monomer is more than or equal to 25 MU and less than or equal to 45 MU, and the compact layer has good application performance under the condition of normal temperature and has soft hand feeling and excellent folding resistance under the condition of low temperature; the problem that an existing leather product is rigid and prone to cracking at low temperature is solved.

Description

Technical Field

[0001] This invention relates to the field of automotive interior leather, and more specifically to a low-temperature resistant artificial leather for automotive interiors. Background Technology

[0002] Automotive interior leather is an important component of automotive interiors, widely used in seats, door panels, center consoles, and other areas. With the promotion and widespread application of new energy vehicles, the requirements for the environmental friendliness, comfort, and weather resistance of automotive interior leather are constantly increasing. Currently, commonly used artificial leather materials mainly include polyvinyl chloride (PVC) artificial leather, polyurethane (PU) artificial leather, and thermoplastic elastomer (TPO) artificial leather.

[0003] However, existing synthetic leather materials have certain shortcomings in low-temperature resistance. PVC synthetic leather, due to the use of large amounts of plasticizers, is prone to problems such as precipitation, hardening, and cracking in low-temperature environments. Although PU synthetic leather has good flexibility, it also cracks at extremely low temperatures. While TPO synthetic leather has environmental advantages, its flexibility and low-temperature flexural resistance need further improvement. Therefore, developing a new type of automotive interior leather material that can maintain good flexibility and flexural resistance in ultra-low temperature environments is urgently needed.

[0004] Various polyolefin compositions have been developed to improve the performance of automotive interior materials. For example, US10513601B2 uses blends of ethylene-propylene copolymers with varying degrees of crystallinity to balance flexibility and strength. US6020046A enhances the elastic recovery and flexibility of materials by introducing polyolefin compositions containing ethylene-α-olefin copolymers. However, these compositions often struggle to maintain sufficient flexibility at temperatures below -20°C, which is a critical requirement for vehicle operation in cold regions.

[0005] US5783629A attempts to improve low-temperature performance by adding thermoplastic polyolefin compositions. These elastomers typically contain ethylene-propylene-diene terpolymers (EPDM) to enhance flexibility. However, achieving the optimal balance between low-temperature flexibility, dimensional stability, and bond strength between multiple layers of automotive interior leather remains challenging. Furthermore, conventional polyolefin materials often suffer from insufficient cross-linking, impacting their overall durability and environmental resistance.

[0006] The applicant proposed a soft, environmentally friendly automotive interior leather in Chinese patent application CN119083189A. The leather base material is a mixture of 10-90 parts by weight of ethylene copolymer elastomer and 10-90 parts by weight of ethylene propylene diene monomer (EPDM) rubber. This base material is subjected to electron irradiation under the action of a crosslinking agent. This automotive interior leather is characterized by its softness and ease of processing. However, experiments have shown that this technical solution cannot fully meet the requirements of maintaining both good softness and folding resistance in automotive interior leather at -30°C.

[0007] In existing technologies, methods such as using adhesive layers or functionally modified polymers are used to address the bonding problems between layers of automotive interior leather. However, these methods are prone to insufficient bond strength at low temperatures, leading to delamination and premature failure of interior components.

[0008] Therefore, it is necessary to develop an automotive interior leather material that maintains excellent softness and elasticity at low temperatures, is resistant to folding, and has high interlayer bonding strength, in order to solve the problems of existing materials feeling stiff and easily becoming brittle and cracking in cold environments, extend the service life of interior parts, and broaden the applicable temperature range. Summary of the Invention

[0009] This invention provides a low-temperature resistant automotive interior leather, comprising a polyolefin substrate layer, the polyolefin substrate layer including a dense layer, the dense layer being composed of a polyolefin composition and additives, the additives being dispersed in the polyolefin composition, the polyolefin composition being composed of an ethylene-α-olefin copolymer as the continuous phase and ethylene propylene diene monomer (EPDM) rubber as the dispersed phase, the dense layer having a crosslinking degree of greater than or equal to 30%, the melting point of the ethylene-α-olefin copolymer being less than or equal to 70°C, and the Mooney viscosity of the EPDM rubber being greater than or equal to 25 MU and less than or equal to 45 MU.

[0010] Further, by weight, the dense layer comprises 100 parts of polyolefin composition and 0.1 to 10 parts of additives.

[0011] Further, by weight, the polyolefin composition comprises 40 to 80 parts of ethylene-α-olefin copolymer and 20 to 60 parts of ethylene propylene diene monomer (EPDM) rubber.

[0012] Furthermore, the additives include 0.01 to 0.5 parts of antioxidant, 0.01 to 0.5 parts of coupling agent, 0.08 to 5 parts of crosslinking agent, and 0 to 5 parts of polyethylene masterbatch.

[0013] Furthermore, EPDM rubber is a copolymer of ethylene, propylene and a small amount of non-conjugated diene, with the non-conjugated diene content in EPDM rubber being not less than 4%.

[0014] Furthermore, the low-temperature resistant automotive interior leather comprises a coating, a polyolefin substrate layer, and a base fabric layer stacked sequentially.

[0015] Furthermore, the polyolefin substrate layer includes a dense layer and an adhesive layer, the adhesive layer being tightly bonded to both the dense layer and the base fabric layer.

[0016] Furthermore, the polyolefin substrate layer also includes a foam layer, which forms a tight bond with the dense layer and the adhesive layer, respectively.

[0017] Furthermore, the adhesive layer comprises a functional group-grafted ethylene-α-olefin copolymer.

[0018] Furthermore, the functional group-grafted ethylene-α-olefin copolymer is a maleic anhydride-grafted ethylene-α-olefin copolymer, and the grafting rate of the maleic anhydride-grafted ethylene-α-olefin copolymer is greater than 1%.

[0019] This application includes at least one of the following beneficial technical effects:

[0020] 1. Using ethylene-α-olefin copolymer with a melting point of less than or equal to 70℃ as the continuous phase, it maintains high resilience at room temperature and has low crystallinity at low temperature, giving the leather a soft feel; it inhibits brittle fracture in low temperature environments (such as -30℃) and significantly improves folding resistance.

[0021] 2. Synergistic mechanism of EPDM toughening and crosslinking

[0022] The mechanical properties of EPDM can be enhanced by dispersing and incorporating it into the continuous phase of ethylene-α-olefins. This enhancement is mainly reflected in the following aspects: 1) Toughening effect: EPDM particles improve the low-temperature impact toughness of the material through stress dispersion and crack pinning effect; 2) Active crosslinking: Utilizing the double bond activity of the third monomer of EPDM, and in conjunction with a co-crosslinking agent, the co-crosslinking reaction between the branched alkanes of the copolymer and EPDM is triggered under electron beam irradiation to construct an interpenetrating network structure.

[0023] 3. It balances the relationship between raw material characteristics and product performance.

[0024] Select EPDM with a Mooney viscosity of 25-45 MU to ensure that it forms a submicron-scale uniform dispersion during the blending process; crosslinking homogenization: optimize the type / dosage of the co-crosslinking agent to match the crosslinking rate of the copolymer and EPDM and avoid local stress concentration; adjust the copolymer / EPDM mass ratio, the content of the third monomer, and the type and dosage of the co-crosslinking agent to ensure that the material can be bent hundreds of thousands of times at -30℃ without cracking.

[0025] In addition, using maleic anhydride-grafted polyolefin (such as MAH-g-POE) as an adhesive layer has good compatibility with the dense layer, and the polar groups (-COOH, anhydride) therein can form hydrogen bonds or covalent bonds with the polar base fabric of the adjacent layer. The adhesive layer melts and penetrates into the fiber pores of the base fabric, and forms a mechanical interlocking structure after curing, which enhances the adhesion under low temperature conditions. Detailed Implementation

[0026] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be described in detail below with reference to specific embodiments. It should be understood that the embodiments described in this specification are merely illustrative and not intended to limit the scope of the invention.

[0027] For simplicity, this paper only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an undefined range; and any lower limit can be combined with other lower limits to form an undefined range, just as any upper limit can be combined with any other upper limit to form an undefined range. Furthermore, although not explicitly stated, every point or individual value between the endpoints of a range is included within that range. Therefore, each point or individual value can serve as its own lower or upper limit and be combined with any other point or individual value, or with other lower or upper limits, to form an undefined range.

[0028] In this description, it should be noted that, unless otherwise stated, "above" and "below" include the stated number, and "multiple" in "one or more" means two or more.

[0029] The above description of the invention is not intended to describe every disclosed embodiment or implementation of the invention. Instead, the following description provides more specific examples of exemplary embodiments. Throughout this application, guidance is provided through a series of embodiments that can be used in various combinations. The examples listed are representative only and should not be construed as exhaustive.

[0030] This invention provides a low-temperature resistant automotive interior leather, comprising a polyolefin substrate layer, the polyolefin substrate layer including a dense layer, the dense layer being composed of a polyolefin composition and additives, the additives being dispersed in the polyolefin composition, the polyolefin composition being composed of an ethylene-alpha olefin copolymer and ethylene propylene diene monomer (EPDM) rubber, the EPDM rubber being dispersed as a dispersed phase within the continuous phase of the ethylene-alpha olefin copolymer, the dense layer having a crosslinking degree of greater than or equal to 30%, the melting point of the ethylene-alpha olefin copolymer being less than or equal to 70°C, and the Mooney viscosity of the EPDM rubber being greater than or equal to 25 MU and less than or equal to 45 MU.

[0031] The automotive interior leather provided by this invention uses polyolefin as the base material. Polyolefin materials produce very little odorous volatile matter. Compared with solvent-based PU automotive interior leather and PVC automotive interior leather with added plasticizers, the automotive interior leather produced by polyolefin has a lower odor and the production process has better environmental performance, thus meeting the requirements of occasions with higher odor and environmental protection requirements.

[0032] In some embodiments, the polyolefin substrate layer includes a dense layer with a thickness of 50 to 800 micrometers.

[0033] In some embodiments, the polyolefin substrate layer includes a dense layer and an adhesive layer, wherein the thickness of the dense layer is 50 to 500 micrometers and the thickness of the adhesive layer is 10 to 300 micrometers.

[0034] In some embodiments, the dense layer is composed of an ethylene-α-olefin copolymer, ethylene propylene diene monomer (EPDM) rubber, and additives.

[0035] In some embodiments, the ethylene-α-olefin copolymer is a copolymer prepared by coordination polymerization or metallocene-catalyzed polymerization of ethylene and α-olefins (such as 1-butene, 1-hexene, 1-octene, etc.). The short branches randomly distributed in the long chain of the copolymer suppress crystallinity and improve flexibility.

[0036] The ethylene-α-olefin copolymer used in this application is a polyolefin composition formed by copolymerizing ethylene with a high content (>20%) of α-olefin. The α-olefin content is generally between 20% and 40%. Its structural characteristics are that the crystalline regions of the polyethylene segments act as physical crosslinking points, and the longer branches introduced by the α-olefin cause the amorphous copolymer to form a rubber phase, thus possessing the characteristics of both plastics and rubber. Compared with propylene elastomers, ethylene elastomers have better overall strength and elongation properties, as well as better long-term heat resistance.

[0037] In some embodiments, ethylene-octene copolymers and ethylene-butene copolymers are preferred. Ethylene-octene copolymers and ethylene-butene copolymers have higher crosslinking activity during electron beam irradiation crosslinking, are less rigid, are less prone to crystallization, and have better low-temperature resistance.

[0038] In some embodiments, the EPDM rubber is a copolymer of ethylene, propylene, and a third monomer having a non-conjugated diene structure. The EPDM rubber contains a third monomer capable of participating in the polymerization reaction, providing crosslinking active sites for the irradiation crosslinking reaction. The third monomer includes ethylene-ide norbornene, dicyclopentadiene, and 1,4-hexadiene, with ethylene-ide norbornene being preferred. Using EPDM rubber with an appropriate content of the third monomer helps to improve the crosslinking density and crosslinking speed of the polyolefin substrate. A third monomer content greater than 4% in the EPDM rubber can provide appropriate crosslinking density and crosslinking speed.

[0039] Ethylene-α-olefin copolymer and ethylene propylene diene monomer (EPDM) rubber have similar polarity. By controlling the ratio of the two, melting and blending conditions, for example, 70 parts of ethylene-α-olefin copolymer and 30 parts of EPDM rubber, shear blending is carried out at the melting point temperature of ethylene-α-olefin copolymer to form a mixed system in which EPDM rubber is uniformly dispersed in the continuous phase of ethylene-α-olefin copolymer.

[0040] In some embodiments, 80 parts of ethylene-α-olefin copolymer and 20 parts of ethylene propylene diene monomer (EPDM) rubber are used.

[0041] In some embodiments, when the ethylene-α-olefin copolymer is less than 40 parts by weight, the ethylene-α-olefin and ethylene propylene diene monomer (EPDM) rubber form a bicontinuous phase structure. Under low-temperature conditions, due to the significant difference in crystallinity between the two phases, the phase interface region becomes a stress concentration source due to the abrupt change in modulus, leading to the initiation of interfacial microcracks.

[0042] In some implementations, when the ethylene-α-olefin copolymer is more than 80 parts by weight, the EPDM rubber cannot provide sufficient mechanical reinforcement and is prone to cracking under low-temperature conditions.

[0043] In some embodiments, irradiation crosslinking causes the third monomer in the EPDM rubber and the active groups of the crosslinking aid in the system to form active crosslinking points, thereby forming a network crosslinking within the ethylene-α olefin copolymer, within the EPDM rubber, and at the interface between the EPDM rubber and the ethylene-α olefin copolymer.

[0044] First, the formation of a cross-linked dense layer has the potential to meet the mechanical properties of automotive interior leather at low temperatures. The formation of cross-links inhibits the formation of low-temperature cracks and improves low-temperature folding resistance. At the same time, it has a soft feel due to the properties of the material itself.

[0045] In some embodiments, the ethylene-α-olefin copolymer has a melting point of less than or equal to 70°C, and the EPDM rubber has a Mooney viscosity of greater than or equal to 25 MU and less than or equal to 45 MU.

[0046] In some embodiments, the ethylene-α-olefin copolymer has a melting point greater than or equal to 50°C and less than or equal to 70°C, and the EPDM rubber has a Mooney viscosity greater than or equal to 30 MU and less than or equal to 45 MU.

[0047] In some embodiments, the ethylene-α-olefin copolymer has a melting point greater than or equal to 40°C and less than or equal to 50°C, and the EPDM rubber has a Mooney viscosity greater than or equal to 20 MU and less than or equal to 30 MU.

[0048] By adjusting the ratio of ethylene-α-olefin copolymer and EPDM rubber, and by controlling the content of the third monomer in EPDM rubber and the intensity of irradiation crosslinking, the mechanical properties of automotive interior leather at low temperatures can be further improved.

[0049] In some embodiments, the polyolefin composition comprises, by weight, 40 to 80 parts of the first ethylene-α-olefin copolymer and 20 to 60 parts of the EPDM rubber.

[0050] In some embodiments, the polyolefin composition comprises 60 to 80 parts of the first ethylene-α-olefin copolymer and 20 to 40 parts of the EPDM rubber.

[0051] In some embodiments, based on 100 parts by weight of the polyolefin composition, the dense layer further comprises 0.1 to 10 parts of an additive.

[0052] In some embodiments, based on 100 parts by weight of the polyolefin composition, the dense layer further contains 0.01 to 0.5 parts of an antioxidant.

[0053] In some embodiments, based on 100 parts by weight of the polyolefin composition, the dense layer further contains 0.01 to 0.5 parts of coupling agent.

[0054] In some embodiments, under irradiation, a crosslinked network can be formed within the continuous phase of the ethylene-α-olefin copolymer, at the interface between the ethylene-α-olefin copolymer and the EPDM rubber blend, and within the EPDM rubber. The amount of crosslinking aid added can be adjusted according to the actual situation.

[0055] In some embodiments, based on 100 parts by weight of the polyolefin composition, the dense layer further comprises 0.08 to 5 parts by weight of a crosslinking aid.

[0056] In some embodiments, based on 100 parts by weight of the polyolefin composition, the dense layer further comprises 1 to 3 parts of a crosslinking aid.

[0057] Examples of crosslinking aids include one or more of diallylamine, diallyl sulfide, N,N-dimethyl-bisacrylamide, ethylene glycol dimethacrylate, triallyl cyanurate, triallyl isocyanurate, trimethylolpropane trimethacrylate, tetramethylolmethane tetraacrylate, glycidyl (meth)acrylate, methyl (meth)acrylate, propoxyglycerol triacrylate, carboxyethyl acrylate, isobornyl (meth)acrylate, 2-hydroxyethyl methacrylate phosphate, and tripropylene glycol diacrylate.

[0058] In some embodiments, crosslinking aids with long carbon chains and multiple functional groups are preferred, such as one or more of trimethylolpropane trimethacrylate, triallyl isocyanurate, propoxyglycerol triacrylate, tetramethylolmethane tetraacrylate, and isoborneol (meth)acrylate. These crosslinking aids help to form interpenetrating networks with higher crosslinking density.

[0059] In some embodiments, the coating may be made of coating materials known in the art for leather, including one or more of polyurethane coatings, acrylic coatings, or silicone coatings. The coating typically possesses suitable abrasion resistance, gloss, and adhesion, which can be selected by those skilled in the art according to actual needs.

[0060] In some embodiments, the base fabric may be one of polyester fabric, nylon fabric, non-woven fabric, linen fabric or composite fabric, and the thickness of the base fabric is preferably 200 to 1000 μm.

[0061] In some embodiments, the adhesive layer is composed of an ethylene-α-olefin copolymer, a functional group-grafted ethylene-α-olefin copolymer, an antioxidant, an adhesive resin, and a filler.

[0062] In some embodiments, the functional group-grafted ethylene-α-olefin copolymer is a maleic anhydride-grafted ethylene-α-olefin copolymer. Using maleic anhydride-grafted polyolefin (such as MAH-g-POE) as the adhesive layer provides good compatibility with the dense layer, and the polar groups (-COOH, anhydride) therein can form hydrogen bonds or covalent bonds with the polar base fabric of adjacent layers. The adhesive layer melts and penetrates into the fiber pores of the base fabric, forming a mechanically interlocking structure after curing, which enhances the adhesion under low-temperature conditions.

[0063] In some embodiments, the grafting rate of maleic anhydride-grafted ethylene-α-olefin copolymer is greater than 1%.

[0064] In some embodiments, the antioxidant is one or more of phosphonates, hindered amines, or hindered phenols, and those skilled in the art can choose according to existing technology.

[0065] In some embodiments, the filler is an organic color masterbatch or an inorganic compound, which can be selected by those skilled in the art based on existing technology.

[0066] In some embodiments, the additives include flame retardants, which can be selected by those skilled in the art based on existing technology.

[0067] Those skilled in the art can prepare the above-mentioned low-temperature resistant automotive interior leather according to existing technology, and conduct sample testing according to the following performance testing methods.

[0068] Example

[0069] The following examples describe the disclosure of this invention in more detail. These examples are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of this disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are based on weight, and the reagents and instruments used in the examples are commercially available.

[0070] The substrate layer materials used in the following embodiments are selected from Table 1:

[0071] Table 1. Raw material grades and related properties used in the examples.

[0072]

[0073] Sample preparation:

[0074] Step 1: Blending and Granulation

[0075] Ethylene-α-olefin copolymer, EPDM, and additives are added to a twin-screw extruder. The temperature of each section is set according to the properties of the materials, as shown in the example below.

[0076] The ethylene-α-olefin copolymer is DF8200, 50 parts by weight; the EPDM is 3032PM, 50 parts by weight; the auxiliary agent is a crosslinking agent, which is trimethylolpropane trimethacrylate, 2 parts by weight.

[0077] Feeding section: 60℃

[0078] Melting section: 100℃

[0079] Nose section: 120℃

[0080] Screw speed: 250 rpm

[0081] Extrusion granulation, followed by cooling and drying of the granules, yields polyolefin composition masterbatch.

[0082] Step 2: Forming of dense layer

[0083] The masterbatch is added to a single-screw extruder and extruded into a film through a T-die. The extrusion temperature is set according to the melting point of the ethylene-α-olefin copolymer.

[0084] Step 3: Lamination and Post-processing

[0085] The base fabric layer and the dense layer are composited using a hot-pressing composite process;

[0086] The coating is applied to the free surface of the dense layer and then dried.

[0087] The dried coating is embossed, cooled and shaped, and then slit.

[0088] Depending on the different requirements of the product's layer structure, adhesive layers and foam layers are prepared.

[0089] The adhesive layer consists of the following components: 90 parts by weight of DF8200, 5 parts by weight of MC329G, 1 part by weight of antioxidant 1010, 1 part by weight of C5 petroleum resin, and 3 parts by weight of color masterbatch are mixed, melted, and extruded into a film, which is then bonded between the dense layer and the base fabric layer.

[0090] The method for preparing the foamed layer is described in the applicant's patent application WO2023279625A1.

[0091] The cross-linking reaction is carried out by electron beam irradiation, and the irradiation dose is set according to the required degree of cross-linking. Those skilled in the art can choose this method themselves.

[0092] Performance testing:

[0093] Tensile strength and elongation at break: GB / T 1040.1-2006 "Determination of tensile properties of plastics"

[0094] Tear strength: GB / T 16578.1-2008 "Plastic films and sheets - Determination of tear resistance"

[0095] Crosslinking degree: Tested by xylene extraction method as specified in GB / T29848-2018 "Ethylene-vinyl acetate copolymer (EVA) film for photovoltaic module encapsulation" (5.5.3).

[0096] Softness (flat pushing method): QB / T 5155-2017 "Test Methods for Artificial Leather and Synthetic Leather - Determination of Softness"

[0097] Low-temperature flexural strength (-30℃): QB-T 2714-2005 "Physical and mechanical tests on leather - Determination of flexural strength"

[0098] Grafting rate test method: NZG / FTIR

[0099] Examples 1-16

[0100] The low-temperature resistant automotive interior leather prepared in Examples 1-13 has a structure in which a base fabric, a dense layer, and a polyurethane coating are stacked sequentially. The base fabric is made of polyester with a thickness of 600 micrometers, the dense layer has a thickness of 500 micrometers, and the coating has a thickness of 50 micrometers. The component ratios of ethylene-α-olefin copolymer and EPDM rubber in the dense layer of each example are shown in Table 2. The difference between Example 13 and Example 6 is that 5 parts of PE masterbatch are added to the dense layer; the difference between Example 14 and Example 6 is that 0.05 parts of antioxidant and 0.05 parts of coupling agent are added to the dense layer; the difference between Example 15 and Example 6 is that a 100-micrometer-thick adhesive layer is sandwiched between the base fabric layer and the dense layer; the difference between Example 16 and Example 15 is that a 300-micrometer-thick foaming layer is sandwiched between the dense layer and the adhesive layer.

[0101] Table 2. Types and proportions of polyolefin substrate layer components in Examples 1-16

[0102]

[0103] Comparative Examples 1-10

[0104] The samples in the comparative examples were prepared according to the method of Example 6. The composition of the dense layer in each comparative example is shown in Table 3.

[0105] Table 3 shows the types and amounts of raw materials used in each comparative example.

[0106]

[0107] The performance of the samples obtained from each embodiment and comparative example was tested, and the results are shown in Table 4:

[0108] Table 4. Performance test results of the examples and comparative examples.

[0109]

[0110]

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the embodiments of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the embodiments described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding embodiments to deviate from the scope of the embodiments of the present invention.

Claims

1. A low-temperature resistant automotive interior leather, comprising a polyolefin substrate layer, the polyolefin substrate layer comprising a dense layer, the dense layer being composed of a polyolefin composition and additives, the additives being dispersed in the polyolefin composition, the polyolefin composition being composed of an ethylene-α-olefin copolymer as a continuous phase and ethylene propylene diene monomer (EPDM) rubber as a dispersed phase, characterized in that... The dense layer has a crosslinking degree of ≥30%, the melting point of the ethylene-α olefin copolymer is ≤70°C, and the Mooney viscosity of the EPDM rubber is ≥25MU and ≤45MU.

2. The low-temperature resistant automotive interior leather according to claim 1, characterized in that, The dense layer comprises 100 parts by weight of the polyolefin composition and 0.1 to 10 parts by weight of the additives.

3. The low-temperature resistant automotive interior leather according to claim 2, characterized in that, The polyolefin composition comprises, by weight, 40 to 80 parts of the ethylene-α-olefin copolymer and 20 to 60 parts of the ethylene propylene diene monomer (EPDM) rubber.

4. The low-temperature resistant automotive interior leather according to claim 2, characterized in that, The additives include 0.01 to 0.5 parts of antioxidant, 0.01 to 0.5 parts of coupling agent, 0.08 to 5 parts of crosslinking agent, and 0 to 5 parts of polyethylene masterbatch.

5. The low-temperature resistant automotive interior leather according to claim 1, characterized in that, The EPDM rubber is a copolymer of ethylene, propylene and a small amount of non-conjugated diene, wherein the content of the non-conjugated diene in the EPDM rubber is not less than 4%.

6. A low-temperature resistant automotive interior leather according to any one of claims 1 to 5, characterized in that, It includes a coating layer, a polyolefin substrate layer, and a base fabric that are stacked in sequence.

7. The low-temperature resistant automotive interior leather according to claim 6, characterized in that, The polyolefin substrate layer includes the dense layer and the adhesive layer, and the adhesive layer forms a tight bond with the dense layer and the base fabric layer respectively.

8. The low-temperature resistant automotive interior leather according to claim 7, characterized in that, The polyolefin substrate layer further includes a foamed layer, which forms a tight bond with the dense layer and the adhesive layer, respectively.

9. The low-temperature resistant automotive interior leather according to claim 7, characterized in that, The adhesive layer comprises a functional group-grafted ethylene-α-olefin copolymer.

10. The low-temperature resistant automotive interior leather according to claim 9, characterized in that, The functional group-grafted ethylene-α olefin copolymer is a maleic anhydride-grafted ethylene-α olefin copolymer, and the grafting rate of the maleic anhydride-grafted ethylene-α olefin copolymer is greater than 1%.

Images