Flame-retardant polyolefin elastomer as well as preparation method and application thereof

Abstract

The invention provides a flame-retardant polyolefin elastomer as well as a preparation method and application thereof. The flame-retardant polyolefin elastomer comprises the following components in percentage by mass: 55-75% of an ethylene structural unit, 20-40% of an alpha-olefin structural unit and 1-5% of a phosphorus group-containing structural unit. The flame-retardant polyolefin elastomer has relatively good flame retardant property and mechanical property.

Description

Technical Field

[0001] This invention relates to the field of polyolefin materials technology, specifically to a flame-retardant polyolefin elastomer, its preparation method, and its application. Background Technology

[0002] With the development trends of lightweight, intelligent, and low-carbon vehicles, traditional interior materials face multiple challenges in terms of environmental protection, functionality, and cost control. Automotive interior materials must meet stringent flame-retardant performance standards while maintaining their mechanical properties.

[0003] Polyolefin elastomers (POEs), as an emerging environmentally friendly material, have attracted widespread attention due to their halogen-free, plasticizer-free, and recyclable characteristics. They possess excellent elasticity, flexibility, weather resistance, low-temperature resistance, and chemical corrosion resistance, and the lack of unsaturated double bonds in their molecular structure gives them outstanding aging resistance. However, traditional POE materials do not inherently possess flame retardancy, requiring flame-retardant modification before use in automotive interiors.

[0004] Therefore, how to make polyolefin elastomers possess both good flame retardant and mechanical properties so that they can be used in automotive interior materials is a research hotspot in the field. Summary of the Invention

[0005] This invention provides a flame-retardant polyolefin elastomer, its preparation method, and its application. The flame-retardant polyolefin elastomer has both good flame-retardant properties and mechanical properties.

[0006] The present invention provides a flame-retardant polyolefin elastomer comprising, by mass percentage, 55% to 75% ethylene structural units, 20% to 40% α-olefin structural units, and 1% to 5% phosphorus-containing structural units.

[0007] Optionally, in the flame-retardant polyolefin elastomer, the mass percentage of the ethylene structural unit is 55% to 70%; and / or, the mass percentage of the α-olefin structural unit is 25% to 40%; and / or, the mass percentage of the phosphorus-containing structural unit is 2% to 5%.

[0008] Optionally, the phosphorus-containing structural unit includes one or more of vinylphosphonic acid structural units, divinylphenylphosphine oxide structural units, acryloyloxyethyl dimethyl phosphate structural units, allyl diphenylphosphine oxide structural units, and vinyl diethyl phosphate structural units; and / or, the α-olefin structural unit includes one or more of butene structural units, hexene structural units, and octene structural units.

[0009] Optionally, the weight-average molecular weight of the flame-retardant polyolefin elastomer is 50,000 to 150,000; and / or, at 190°C and a load of 2.16 kg, the melt mass flow rate of the flame-retardant polyolefin elastomer is 0.5 g / 10 min to 30 g / 10 min, preferably 1 g / 10 min to 13 g / 10 min.

[0010] The present invention provides a method for preparing the flame-retardant polyolefin elastomer as described above, comprising: copolymerizing a raw material system including ethylene, α-olefin and a monomer containing phosphorus groups under the action of a catalyst system to obtain the flame-retardant polyolefin elastomer.

[0011] Optionally, the catalyst system includes a main catalyst and a co-catalyst; wherein the main catalyst includes nickel bis(trifluoromethanesulfonyl)imine, [1,3-bis(2,6-diisopropylphenyl)imidazol-2-yl]palladium, [1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylyl](3-chloropyridinyl)palladium dichloride, bis(di-tert-butylphenylphosphine)palladium dichloride, diphenylmethylene(cyclopentadiene)(9-fluorenyl)zirconium dichloride, dimethyldimethylsilylbis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride, (bis(methylcyclopentadiene)zirconium dichloride), and diphenylsilyl(cyclopentadiene). One or more of the following: (9-fluorenyl)zirconia, diphenylmethylenecyclopentadiene(2,7-di-tert-butyl-fluorenyl)zirconia, di-p-tolymethylenecyclopentadiene(2,7-di-tert-butyl-fluorenyl)zirconia, dimethylsilylbis(2-methyl-4-phenylindinyl)zirconia, dimethsilyl(N-tert-butylamino)(tetramethylcyclopentadienyl)titanium dichloride, dimethsilyl(N-tert-butylamino)(tetramethylcyclopentadienyl)dimethyltitanium, dimethsilyl(N-tert-butylamino)(fluorenyl)titanium dichloride, and (pentamethylcyclopentadienyl)trimethoxytitanium; the co-catalyst comprises at least one of alkylaluminum, organoboron compounds, and alkylaluminoxanes, preferably one or more of methylaluminoxane, modified methylaluminoxane, ethylaluminoxane, trimethylaluminum, triethylaluminum, triisobutylaluminum, and tri(pentafluorophenyl)boron.

[0012] Optionally, the phosphorus-containing monomer includes one or more of vinylphosphonic acid, divinylphenylphosphine oxide, acryloyloxyethyl dimethyl phosphate, allyl diphenylphosphine oxide, and vinyl diethyl phosphate; and / or, the α-olefin includes one or more of butene, hexene, and octene.

[0013] The present invention provides a leather, wherein the raw material of the leather includes the flame-retardant polyolefin elastomer as described above or the flame-retardant polyolefin elastomer obtained according to the preparation method described above.

[0014] Optionally, the raw material of the leather further includes one or more of the following: a crosslinking agent, an inorganic metal oxide, and an antioxidant; preferably, the mass ratio of the flame-retardant polyolefin elastomer to the crosslinking agent is 100:(0.1~5); the mass ratio of the flame-retardant polyolefin elastomer to the inorganic metal oxide is 100:(0.01~1); the mass ratio of the flame-retardant polyolefin elastomer to the antioxidant is 100:(0.01~1); preferably, the crosslinking agent includes 2-hydroxyethyl methacrylate phosphate, tetraphenyl bisphenol A diphosphate, bisphenol A bis(diphenyl) phosphate, triallyl isocyanurate, trimethyl diphenyl phosphate, and 2-ethylhexyl diphenyl phosphate. The antioxidant comprises one or more of the following: ester, isodecanyl diphenyl phosphate, tributoxyethyl phosphate, and tetraphenyl-resorcinol diphosphate; the inorganic metal oxide comprises one or more of the following: zinc oxide, magnesium oxide, and aluminum oxide; the antioxidant comprises one or more of the following: β-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,2-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine, 2,2'-oxamido-bis[ethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)]propionate, and tris[2,4-di-tert-butylphenyl]phosphite.

[0015] The present invention provides a method for preparing leather as described above, comprising: mixing the raw materials of the leather, forming a film by casting, and then subjecting the film to electron beam irradiation crosslinking to obtain the leather.

[0016] This invention provides a flame-retardant polyolefin elastomer, its preparation method, and its applications. By rationally controlling the ratio of ethylene structural units to α-olefin structural units, it achieves excellent mechanical properties, specifically high tensile strength and superior tear resistance. Simultaneously, phosphorus-containing structural units are introduced into the molecular structure of the flame-retardant polyolefin elastomer, thereby imparting significant flame-retardant properties. The automotive interior leather layer prepared based on the above-mentioned flame-retardant polyolefin elastomer not only retains the inherent advantages of polyolefin materials, such as environmental friendliness, recyclability, aging resistance, and comfortable feel, but also achieves a good balance between flame retardancy and mechanical properties: on the one hand, it has a high flame-retardant rating, meeting the fire safety requirements of automotive interior materials; on the other hand, it still possesses superior tensile and tear properties, ensuring its durability and structural integrity during long-term use. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below. The specific embodiments listed below are merely descriptions of the principles and features of the present invention, and the examples are only for explaining the present invention and are not intended to limit the scope of the present invention. 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.

[0018] As the automotive industry undergoes profound transformation towards lightweighting, intelligentization, and low-carbonization, automotive interior materials face new performance and environmental requirements. Traditional automotive interior synthetic leathers mostly use solvent-based polyurethane (PU) systems, which release large amounts of volatile organic compounds during production and use, posing a significant threat to the environment and the health of drivers and passengers. Furthermore, these materials often fall short of natural leather in terms of abrasion resistance, scratch resistance, breathability, and softness. While natural leather boasts superior performance, its scarcity and high cost make it difficult to meet the demands of large-scale automotive manufacturing. Against this backdrop, the market urgently needs an alternative interior leather material that combines environmental friendliness, excellent overall performance, and high cost-effectiveness.

[0019] Polyolefin elastomers (POEs), as an emerging environmentally friendly material, have attracted widespread attention due to their halogen-free, plasticizer-free, and recyclable characteristics. They possess excellent elasticity, flexibility, weather resistance, low-temperature resistance, and chemical corrosion resistance, and the lack of unsaturated double bonds in their molecular structure gives them outstanding aging resistance. However, traditional POE materials do not inherently possess flame retardancy, requiring flame-retardant modification for use in automotive interiors. Currently, the industry is gradually phasing out halogenated flame retardants that produce toxic substances, while halogen-free flame retardants, although environmentally friendly, typically require large amounts to meet flame-retardant standards, often resulting in a noticeably harder feel and reduced comfort. Furthermore, existing flame-retardant modification methods mostly employ physical blending or post-treatment, leading to complex processes that increase production costs and processing difficulty.

[0020] Therefore, achieving flame-retardant properties in POE interior leather in a more economical and efficient manner, while ensuring a comfortable feel and meeting environmental requirements, has become a key technological breakthrough in the industry. This invention aims to achieve integrated control of the material's flame-retardant and mechanical properties by introducing specific flame-retardant monomers during the POE synthesis stage, starting from polymer molecular structure design. This avoids the need for large amounts of subsequent flame retardant additions, simplifies the processing flow, and provides a high-performance, environmentally friendly, and feasible leather layer solution for automotive interiors.

[0021] Based on this, embodiments of the present invention provide a flame-retardant polyolefin elastomer, comprising, by mass percentage, 55%~75% ethylene structural units, 20%~40% α-olefin structural units, and 1%~5% phosphorus-containing structural units.

[0022] According to research and analysis, the flame-retardant polyolefin elastomer of this invention, by rationally controlling the ratio of ethylene structural units to α-olefin structural units, possesses excellent mechanical properties, specifically high tensile strength and excellent tear resistance. Simultaneously, phosphorus-containing structural units are introduced into the molecular structure of the flame-retardant polyolefin elastomer, thereby achieving significant flame-retardant properties. The automotive interior leather layer prepared based on the above-mentioned flame-retardant polyolefin elastomer not only maintains the inherent advantages of polyolefin materials such as environmental friendliness, recyclability, aging resistance, and comfortable feel, but also achieves a good balance between flame retardancy and mechanical properties: on the one hand, it has a high flame-retardant rating, meeting the fire safety requirements of automotive interior materials; on the other hand, it still possesses superior tensile and tear properties, ensuring its durability and structural integrity during long-term use.

[0023] For example, in the flame-retardant polyolefin elastomer, the mass percentage of ethylene structural units can be 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, or any combination thereof; the mass percentage of α-olefin structural units can be 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, or any combination thereof; and the mass percentage of phosphorus-containing structural units can be 1%, 2%, 3%, 4%, 5%, or any combination thereof.

[0024] Preferably, in the flame-retardant polyolefin elastomer, the mass percentage of ethylene structural units can be 55% to 70%; the mass percentage of α-olefin structural units can be 25% to 40%; and the mass percentage of phosphorus-containing structural units can be 2% to 5%.

[0025] The aforementioned flame-retardant polyolefin elastomer can be a random copolymer.

[0026] In some embodiments, the phosphorus-containing structural units include one or more of vinylphosphonic acid structural units, divinylphenylphosphine oxide structural units, acryloyloxyethyl dimethyl phosphate structural units, allyl diphenylphosphine oxide structural units, and vinyl diethyl phosphate structural units. Introducing these phosphorus-containing structural units into the molecular structure of flame-retardant polyolefin elastomers results in significant flame-retardant properties.

[0027] The structural formula of the vinylphosphonic acid structural unit is shown in Formula 1.

[0028] Formula 1

[0029] In some embodiments, the α-olefin structural unit includes one or more of butene, hexene, and octene structural units. By introducing the above-mentioned α-olefin structural units, the flame-retardant polyolefin elastomer possesses excellent mechanical properties, specifically high tensile strength and excellent tear resistance.

[0030] In one specific embodiment, the structural formula of the above-mentioned flame-retardant polyolefin elastomer is shown in Formula 2.

[0031] Formula 2

[0032] In Equation 2, x is greater than 0, y is greater than 0, and z is greater than 0.

[0033] In some embodiments, the weight-average molecular weight of the flame-retardant polyolefin elastomer is 50,000 to 200,000.

[0034] For example, the weight-average molecular weight (M) of the above-mentioned flame-retardant polyolefin elastomer W The range can be 50000, 55000, 60000, 65000, 70000, 75000, 80000, 85000, 90000, 95000, 100000, 105000, 110000, 115000, 120000, 125000, 130000, 135000, 140000, 145000, 150000, 155000, 160000, 165000, 170000, 175000, 180000, 185000, 190000, 195000, 200000, or any combination thereof.

[0035] The weight-average molecular weight of flame-retardant polyolefin elastomers is controlled within the range of 50,000 to 200,000. This ensures suitable processing flowability and film-forming stability while imparting good tensile and tear strength, resulting in excellent mechanical durability. Within this molecular weight range, the flame-retardant structural units introduced through copolymerization can be effectively dispersed and function, achieving a balance between flame-retardant performance and material feel, ensuring that the polyolefin elastomer possesses both a high flame-retardant rating and a comfortable, soft touch.

[0036] In some embodiments, at 190°C and a load of 2.16 kg, the melt mass flow rate (MFR) of the flame-retardant polyolefin elastomer is 1 g / 10 min to 50 g / 10 min.

[0037] For example, at 190°C and a load of 2.16 kg, the melt mass flow rate of the flame-retardant polyolefin elastomer can be a range of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50 (all in g / 10 min) or any combination thereof.

[0038] Flame-retardant polyolefin elastomers with melt flow rates meeting the above-mentioned range exhibit good processing and mechanical properties. When the melt flow rate is not less than 1 g / 10 min, the flame-retardant polyolefin elastomer has sufficient fluidity during melt processing (such as casting), ensuring smooth processing and a uniform leather surface. When the melt flow rate is not higher than 30 g / 10 min, the flame-retardant polyolefin elastomer can maintain sufficient melt strength, preventing the film from sagging or tearing during molding, thereby ensuring that the final leather product has good tensile strength, tear resistance, and dimensional stability.

[0039] This invention also provides a method for preparing a flame-retardant polyolefin elastomer, comprising: copolymerizing a raw material system including ethylene, α-olefin and a phosphorus-containing monomer under the action of a catalyst system to obtain a flame-retardant polyolefin elastomer.

[0040] This invention introduces a phosphorus-containing third monomer (i.e., a phosphorus-based monomer or a phosphorus-based flame-retardant monomer) into the polymerization stage of the polyolefin elastomer for copolymerization, thereby achieving flame-retardant properties at the resin matrix end. This eliminates the need for post-processing steps involving the addition and blending of flame retardants required in traditional leather manufacturing. This simplifies the processing flow and avoids problems such as decreased mechanical properties, hardened feel, and reduced comfort caused by the addition of inorganic flame retardants or large amounts of halogen-free flame retardants. The final product is a flame-retardant polyolefin elastomer with excellent flame retardancy, mechanical properties, and a soft feel, which can be used in automotive interior leather layers. This preparation method is simple, suitable for large-scale production, and can directly provide downstream leather manufacturers with polyolefin elastomer raw material particles with differentiated flame-retardant properties.

[0041] In some embodiments, the phosphorus-containing monomers include one or more of vinylphosphonic acid, divinylphenylphosphine oxide, acryloyloxyethyl dimethyl phosphate, allyl diphenylphosphine oxide, and vinyl diethyl phosphate.

[0042] The structural formula of vinylphosphonic acid is shown in Formula 3.

[0043] Formula 3

[0044] In some embodiments, α-olefins include one or more of butene, hexene, and octene.

[0045] The catalyst system described above may include a main catalyst and a co-catalyst.

[0046] Specifically, the main catalyst may include nickel di(trifluoromethanesulfonyl)imine, [1,3-bis(2,6-diisopropylphenyl)imidazol-2-yl]palladium, [1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylyl](3-chloropyridinyl)palladium dichloride, bis(di-tert-butylphenylphosphine)palladium dichloride, diphenylmethylene(cyclopentadiene)(9-fluorenyl)zirconium dichloride, dimethyldimethylsilylbis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride, (bis(methylcyclopentadiene)zirconium dichloride), and diphenylsilyl(cyclopentadiene). One or more of the following: (9-fluorenyl)zirconia, diphenylmethylenecyclopentadiene(2,7-di-tert-butyl-fluorenyl)zirconia, di-p-tolymethylenecyclopentadiene(2,7-di-tert-butyl-fluorenyl)zirconia, dimethylsilylbis(2-methyl-4-phenylindinyl)zirconia, dimethsilyl(N-tert-butylamino)(tetramethylcyclopentadienyl)titanium dichloride, dimethsilyl(N-tert-butylamino)(tetramethylcyclopentadienyl)dimethyltitanium, dimethsilyl(N-tert-butylamino)(fluorenyl)titanium dichloride, and (pentamethylcyclopentadienyl)trimethoxytitanium.

[0047] The cocatalyst may include at least one of alkylaluminum, organoboron compounds, and alkylaluminoxanes, preferably one or more of methylaluminoxane, modified methylaluminoxane, ethylaluminoxane, trimethylaluminum, triethylaluminum, triisobutylaluminum, and tris(pentafluorophenyl)boron.

[0048] The embodiments of the present invention do not impose any particular limitation on the amount of the main catalyst and the co-catalyst described above.

[0049] The temperature for the above copolymerization reaction can be 150℃-180℃.

[0050] In this embodiment of the invention, the time for the above copolymerization reaction is not particularly limited; for example, it can be 5-30 minutes.

[0051] In specific implementation, the above preparation method may include: mixing ethylene, α-olefin and an inert organic solvent, then controlling the temperature to the expected temperature of the copolymerization reaction, then introducing ethylene gas and controlling the pressure of the reaction system to be appropriate, then adding the main catalyst and co-catalyst, and carrying out the copolymerization reaction under stirring to obtain a solution containing the reactants; after quenching the copolymerization reaction, cooling, filtering and drying the reaction system to obtain a flame-retardant polyolefin elastomer.

[0052] The aforementioned inert organic solvents may include C8-C9 isoalkane solvents such as Isopar E.

[0053] The pressure of the reaction system can be 1.5-3.0 MPa.

[0054] The process of quenching the copolymerization reaction may include mixing a mixture of water and 3-methyl-2,4-nonanedione with a solution containing the reactants to quench the copolymerization reaction. Specifically, the mass ratio of water to 3-methyl-2,4-nonanedione may be (1-1.5):1.

[0055] In this embodiment of the invention, the amount of the mixture of water and 3-methyl-2,4-nonanedione is not particularly limited.

[0056] For example, the above preparation method may include: adding ethylene and α-olefin to an inert organic solvent, then controlling the temperature to the expected temperature of the copolymerization reaction, then introducing ethylene gas and controlling the pressure of the reaction system appropriately, then adding the main catalyst and co-catalyst, and then carrying out the copolymerization reaction under stirring to obtain a solution containing the reactants; after quenching the copolymerization reaction, cooling, filtering and drying the reaction system to obtain a flame-retardant polyolefin elastomer.

[0057] The above-mentioned method of adding the co-catalyst may include preparing a toluene solution containing the co-catalyst, and then adding the toluene solution containing the co-catalyst and the main catalyst into the system. In this embodiment of the invention, the mass percentage of the co-catalyst in the toluene solution containing the co-catalyst is not particularly limited, for example, it can be 3-9%.

[0058] This invention provides a type of leather, the raw material of which includes the above-mentioned flame-retardant polyolefin elastomer or the flame-retardant polyolefin elastomer obtained by the above preparation method.

[0059] Based on this flame-retardant polyolefin elastomer, the aforementioned leather has advantages such as being environmentally friendly, recyclable, aging-resistant, and having a comfortable feel. Furthermore, it achieves a good balance between flame retardancy and mechanical properties: on the one hand, it has a high flame retardancy rating, which can meet the fire safety requirements of automotive interior materials; on the other hand, it still has excellent tensile and tear properties, ensuring its durability and structural integrity in long-term use.

[0060] Specifically, the raw materials for the aforementioned leather may also include one or more of the following: cross-linking agents, inorganic metal oxides, and antioxidants.

[0061] Furthermore, the mass ratio of flame-retardant polyolefin elastomer to co-crosslinking agent can be 100:(0.1~5), for example, 100:0.1, 100:0.5, 100:1, 100:1.5, 100:2, 100:2.5, 100:3, 100:3.5, 100:4, 100:4.5, 100:5 or any combination thereof.

[0062] The mass ratio of flame-retardant polyolefin elastomer to inorganic metal oxide can be 100:(0.01~1), for example, 100:0.01, 100:0.05, 100:0.1, 100:0.2, 100:0.3, 100:0.4, 100:0.5, 100:0.6, 100:0.7, 100:0.8, 100:0.9, 100:1 or any combination thereof.

[0063] The mass ratio of flame-retardant polyolefin elastomer to antioxidant can be 100:(0.01~1), for example, 100:0.01, 100:0.05, 100:0.1, 100:0.2, 100:0.3, 100:0.4, 100:0.5, 100:0.6, 100:0.7, 100:0.8, 100:0.9, 100:1 or any combination thereof.

[0064] In addition, the crosslinking agent may include one or more of the following: 2-hydroxyethyl methacrylate phosphate, tetraphenyl bisphenol A diphosphate, bisphenol A bis(diphenyl) phosphate, triallyl isocyanurate, trimethyl diphenyl phosphate, 2-ethylhexyl diphenyl phosphate, isodecyl diphenyl phosphate, tributoxyethyl phosphate, and tetraphenyl resorcinol diphosphate.

[0065] Inorganic metal oxides may include one or more of zinc oxide, magnesium oxide, and aluminum oxide.

[0066] Antioxidants may include one or more of the following: β-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,2-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine, 2,2'-oxamido-bis[ethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)]propionate, and tris[2,4-di-tert-butylphenyl]phosphite.

[0067] The present invention also provides a method for preparing the above-mentioned leather, comprising: mixing the raw materials of leather, forming a film by casting, and then subjecting the film to electron beam irradiation crosslinking to obtain leather.

[0068] It is understood that the raw materials for the leather mentioned above include the flame-retardant polyolefin elastomer of the present invention.

[0069] The above preparation method can produce a type of leather that has advantages such as being environmentally friendly, recyclable, resistant to aging, and comfortable to the touch. It also achieves a good balance between flame retardancy and mechanical properties: on the one hand, it has a high flame retardancy rating, which can meet the fire safety requirements of automotive interior materials; on the other hand, it still has excellent tensile and tear properties, ensuring its durability and structural integrity in long-term use.

[0070] The dose of electron beam irradiation can be 30-80 kGy.

[0071] In this embodiment of the invention, electron beam irradiation typically refers to beta-ray irradiation.

[0072] In specific implementation, the above-mentioned leather preparation method includes: mixing the raw materials of leather, forming a film material by casting, cooling and winding, and then subjecting the film material to electron beam irradiation crosslinking to obtain leather with a crosslinking degree of at least 40%.

[0073] According to the GB / T 5455-2014 (vertical method) test, the vertical burning time of the leather in this embodiment of the invention is ≤250s, and according to the GB / T 8332-2008 (horizontal method) test, the horizontal burning speed of the leather in this embodiment of the invention is ≤30mm / min.

[0074] According to the test method of GB / T 528, the elongation at break of the leather in the embodiment of the present invention is ≥800%, and the tensile strength is ≥9MPa.

[0075] The present invention will be further described below through specific embodiments and comparative examples. Unless otherwise specified, the reagents, materials and instruments used below are all conventional reagents, materials and instruments, all of which are commercially available, and the reagents and materials involved can also be synthesized by conventional synthetic methods.

[0076] 2(trifluoromethylsulfonyl)imine nickel, Shanghai Maclean Biochemical Technology Co., Ltd.

[0077] Dimethylsilyl bis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride, Wuxi Yaodexin Chemical Products Co., Ltd.

[0078] Methylaluminoxane, Nourion Chemicals Ltd.

[0079] Triallyl isocyanurate, Hefei Anbang Chemical Co., Ltd.

[0080] β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate n-octadecyl alcohol ester (antioxidant 1076), Lianlong New Materials Co., Ltd.

[0081] Tris[2,4-di-tert-butylphenyl]phosphite (antioxidant 168), Lianlong New Materials Co., Ltd.

[0082] Zinc oxide, Aladdin Biochemical Technology Co., Ltd.

[0083] Diethylaluminum hypophosphite, Shouguang Puer Chemical Co., Ltd.

[0084] Melamine cyanuric acid, Shouguang Puer Chemical Co., Ltd.

[0085] Isopar E, ExxonMobil.

[0086] Example 1

[0087] 1) Preparation of flame-retardant polyolefin elastomers.

[0088] 180g of octene and 15g of vinylphosphonic acid were added to 1L of Isopar E to prepare a solution, which was then added to a reaction vessel. The temperature was raised to 155℃, ethylene gas was introduced, and the pressure inside the vessel was controlled at 2.7MPa. Then, 1mg of the main catalyst, nickel di(trifluoromethanesulfonyl)imide, and 5ml of the co-catalyst, a 10wt% methylaluminoxane toluene solution, were added to the reaction vessel and stirred for copolymerization for 15min to obtain a solution containing the reactants. Then, water and 3-methyl-2,4-nonanedione were mixed at a mass ratio of 1:1 to obtain a mixed solution. 600mg of the mixed solution was fully reacted with the solution containing the reactants to quench the copolymerization reaction. The obtained product was then cooled, filtered, and dried to obtain flame-retardant polyolefin elastomer A or ethylene-octene-phosphorus copolymer A.

[0089] 2) Leather preparation.

[0090] Add triallyl isocyanurate, zinc oxide, and antioxidant to ethylene-octene-phosphorus copolymer A to obtain leather raw material. Then heat the leather raw material, cast it into a film, cool and roll it up, and irradiate it with 50KGY of β rays to obtain leather, namely the leather layer in automotive interior leather.

[0091] The mass ratio of ethylene-octene-phosphorus copolymer A to triallyl isocyanurate is 100:0.5, the mass ratio of ethylene-octene-phosphorus copolymer A to zinc oxide is 100:0.01, the antioxidants include antioxidant 1076 and antioxidant 168 in a mass ratio of 1:1, and the mass ratio of ethylene-octene-phosphorus copolymer A to antioxidants is 100:0.2.

[0092] Example 2

[0093] This embodiment is basically the same as Embodiment 1, except that:

[0094] 1) During the preparation of flame-retardant polyolefin elastomer, the mass of octene was adjusted to 165g, the mass of vinylphosphonic acid was adjusted to 22g, and the pressure inside the reactor was adjusted to 2.8MPa; other conditions remained unchanged.

[0095] The flame-retardant polyolefin elastomer of Example 2 is designated as flame-retardant polyolefin elastomer B or ethylene-octene-phosphorus copolymer B.

[0096] Example 3

[0097] This embodiment is basically the same as Embodiment 1, except that:

[0098] 1) In the preparation of flame-retardant polyolefin elastomer, the mass of octene was adjusted to 160g, the mass of vinylphosphonic acid was adjusted to 40g, the temperature of the copolymerization reaction was adjusted from 155℃ to 160℃, the pressure inside the reactor was adjusted to 2.8MPa, and the polymerization reaction time was extended to 20min; other conditions remained unchanged.

[0099] The flame-retardant polyolefin elastomer of Example 3 is denoted as Flame-retardant Polyolefin Elastomer C or Ethylene-Octene-Phosphorus Copolymer C.

[0100] Example 4

[0101] This embodiment is basically the same as Embodiment 1, except that:

[0102] 1) In the preparation of flame-retardant polyolefin elastomer, butene is replaced with octene, the mass of butene is adjusted to 160g, the mass of vinylphosphonic acid is adjusted to 40g, the temperature of the copolymerization reaction is adjusted from 155℃ to 150℃, the pressure inside the reactor is adjusted to 3.0MPa, and other conditions remain unchanged.

[0103] The flame-retardant polyolefin elastomer of Example 4 is designated as flame-retardant polyolefin elastomer D or ethylene-butene-phosphorus copolymer D.

[0104] 2) During the leather preparation process, the mass ratio of ethylene-butene-phosphorus copolymer D to triallyl isocyanurate was adjusted to 100:0.1, the mass ratio of ethylene-butene-phosphorus copolymer D to zinc oxide was 100:0.1, the antioxidants included antioxidant 1076 and antioxidant 168 in a mass ratio of 1:1, and the mass ratio of ethylene-butene-phosphorus copolymer D to antioxidants was 100:0.01. Other conditions remained unchanged.

[0105] Example 5

[0106] This embodiment is basically the same as Embodiment 1, except that:

[0107] 1) In the preparation of flame-retardant polyolefin elastomer, octene was replaced with hexene, the mass of hexene was adjusted to 160g, the mass of vinylphosphonic acid was adjusted to 40g, the temperature of the copolymerization reaction remained unchanged, and the pressure inside the reactor was adjusted to 2.8MPa; other conditions remained unchanged.

[0108] The flame-retardant polyolefin elastomer of Example 5 is denoted as flame-retardant polyolefin elastomer E or ethylene-hexene-phosphorus copolymer E.

[0109] 2) The mass ratio of ethylene-hexene-phosphorus copolymer E to triallyl isocyanurate is 100:5, the mass ratio of ethylene-hexene-phosphorus copolymer E to zinc oxide is 100:1, and the antioxidants include antioxidant 1076 and antioxidant 168 in a mass ratio of 1:1. The mass ratio of ethylene-hexene-phosphorus copolymer E to antioxidants is 100:1. Other conditions remain unchanged.

[0110] Example 6

[0111] This embodiment is basically the same as Embodiment 1, except that:

[0112] 1) During the preparation of flame-retardant polyolefin elastomer, the mass of octene was adjusted to 135g, the mass of vinylphosphonic acid was adjusted to 40g, the pressure inside the reactor was adjusted to 3.0MPa, the polymerization reaction time was extended to 25min, and other conditions remained unchanged.

[0113] The flame-retardant polyolefin elastomer of Example 6 is designated as flame-retardant polyolefin elastomer F or ethylene-octene-phosphorus copolymer F.

[0114] Example 7

[0115] This embodiment is basically the same as Embodiment 1, except that:

[0116] 1) During the preparation of flame-retardant polyolefin elastomer, the mass of octene was adjusted to 195g, the mass of vinylphosphonic acid was adjusted to 40g, the pressure inside the reactor was adjusted to 2.5MPa, the polymerization reaction time was shortened to 12min, and other conditions remained unchanged.

[0117] The flame-retardant polyolefin elastomer of Example 7 is designated as flame-retardant polyolefin elastomer G or ethylene-octene-phosphorus copolymer G.

[0118] Comparative Example 1

[0119] This comparative example is basically the same as Example 1, except that: 1) the preparation of the flame-retardant polyolefin elastomer is different; other conditions remain unchanged. The specific preparation process of the flame-retardant polyolefin elastomer in this comparative example includes: using cationic metallocene coordination polymerization, 200g of octene is added to 1L of Isopar E to form a solution, which is then added to a reactor. The temperature is raised to 150°C, ethylene gas is introduced, and the pressure inside the reactor is controlled at 2.5MPa. 1mg of the main catalyst, dimethylsilylbis(2-methyl-4-phenylindidine)zirconia dichloride, and 5ml of the co-catalyst, a 10wt% methylaluminoxane toluene solution, are added to the reactor and stirred for 15min to obtain a reactant solution. Water and 3-methyl-2,4-nonanedione are mixed at a mass ratio of 1:1, and the total mass of the mixture (900mg) reacts fully with the reactant solution. The obtained product is cooled, filtered, and dried to obtain ethylene-octene copolymer H.

[0120] Comparative Example 2

[0121] This comparative example is basically the same as Comparative Example 1, except that the leather preparation process is different, while other conditions remain unchanged. The specific leather preparation process of this comparative example includes: adding 5g of aluminum diethylphosphite, 10g of melamine cyanurate, 0.05g of antioxidant 1076, and 0.05g of antioxidant 168 to 100g of ethylene-octene copolymer H to obtain raw materials; mixing these raw materials evenly using a high-speed mixer and then granulating them using a twin-screw extruder to obtain mixture M; adding 0.5g of triallyl isocyanurate, 0.01g of zinc oxide, 0.1g of antioxidant 1076, and 0.1g of antioxidant 168 to 100g of mixture M; then heating and mixing, casting into a film, cooling and winding; and finally irradiating with 50KGY of β rays to obtain leather, i.e., the leather layer in automotive interior leather.

[0122] Test case

[0123] The following parameters of the flame-retardant polyolefin elastomers and leathers of each embodiment and comparative example were tested:

[0124] (1) Flame-retardant polyolefin elastomer.

[0125] a. Mass percentage of each structural unit of the flame-retardant polyolefin elastomer: determined by nuclear magnetic resonance hydrogen spectroscopy, with the test standard referring to ASTM D5017.

[0126] b. Weight-average molecular weight of flame-retardant polyolefin elastomer: determined by gel permeation chromatography, using polystyrene as a standard and trichlorobenzene as a solvent, at 150°C.

[0127] c. Melt mass flow rate of flame-retardant polyolefin elastomer at 190°C and 2.16 kg load: determined according to ASTM D1238 or GB / T 3682.1 standard methods.

[0128] (2) Leather.

[0129] a. Tensile strength and elongation at break of leather: Tensile test shall be performed using dumbbell-shaped specimens at a rate of (500±50) mm / min, in accordance with GB / T 1040.3-2006 standard.

[0130] b. Tear strength of leather: In accordance with GB / T 529-2008 standard, an uncut right-angled specimen was used for tear testing at a rate of (100±10) mm / min.

[0131] c. Vertical burning time of leather: Flame retardant performance test shall be conducted in accordance with GB / T 5455-2014 (vertical method).

[0132] d. Horizontal burning rate of leather: Flame retardant performance test shall be conducted in accordance with GB / T 8332-2008 (horizontal method).

[0133] The test results are shown in Tables 1 and 2.

[0134] Table 1 Parameters of Flame-Retardant Polyolefin Elastomers

[0135]

[0136] Table 2 Parameters of Leather

[0137]

[0138] The flame-retardant polyolefin elastomer and the leather or leather layer made therefrom provided in this invention start from the synthesis stage of the flame-retardant polyolefin elastomer, introducing phosphorus-containing structural units or phosphorus-based flame-retardant components in the form of monomers, thereby significantly improving the flame-retardant properties of the flame-retardant polyolefin elastomer. Furthermore, compared with externally added flame retardants, the flame-retardant polyolefin elastomer used in this invention does not cause a significant reduction in the mechanical properties of the leather. By adjusting the proportion of phosphorus-containing structural unit flame-retardant monomers, the flame-retardant and mechanical properties of the flame-retardant polyolefin elastomer can be controlled, avoiding the large-scale use of flame retardants while simplifying the processing flow, which is beneficial for large-scale production.

[0139] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; 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 technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flame-retardant polyolefin elastomer, characterized in that, The weight percentage includes 55% to 75% ethylene structural units, 20% to 40% α-olefin structural units, and 1% to 5% phosphorus-containing structural units.

2. The flame-retardant polyolefin elastomer according to claim 1, characterized in that, In the flame-retardant polyolefin elastomer, the ethylene structural unit has a mass percentage content of 55% to 70%. And / or, the α-olefin structural unit has a mass percentage content of 25% to 40%; And / or, the mass percentage of the phosphorus-containing structural unit is 2% to 5%.

3. The flame-retardant polyolefin elastomer according to claim 1 or 2, characterized in that, The phosphorus-containing structural unit includes one or more of the following: vinylphosphonic acid structural unit, divinylphenylphosphine oxide structural unit, acryloyloxyethyl dimethyl phosphate structural unit, allyl diphenylphosphine oxide structural unit, and vinyl diethyl phosphate structural unit. And / or, the α-olefin structural unit includes one or more of butene structural units, hexene structural units, and octene structural units.

4. The flame-retardant polyolefin elastomer according to any one of claims 1-3, characterized in that, The weight-average molecular weight of the flame-retardant polyolefin elastomer is 50,000 to 150,000. And / or, at 190°C and a load of 2.16 kg, the melt mass flow rate of the flame-retardant polyolefin elastomer is 0.5 g / 10 min to 30 g / 10 min, preferably 1 g / 10 min to 13 g / 10 min.

5. A method for preparing the flame-retardant polyolefin elastomer according to any one of claims 1-4, characterized in that, include: Under the action of a catalyst system, a raw material system including ethylene, α-olefin and phosphorus-containing monomers is copolymerized to obtain the flame-retardant polyolefin elastomer.

6. The method for preparing the flame-retardant polyolefin elastomer according to claim 5, characterized in that, The catalyst system includes a main catalyst and a co-catalyst; The main catalysts include nickel bis(trifluoromethanesulfonyl)imine, [1,3-bis(2,6-diisopropylphenyl)imidazol-2-yl]palladium, [1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylyl](3-chloropyridinyl)palladium dichloride, bis(di-tert-butylphenylphosphine)palladium dichloride, diphenylmethylene(cyclopentadiene)(9-fluorenyl)zirconium dichloride, dimethyldimethylsilylbis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride, (bis(methylcyclopentadiene)zirconium dichloride), and diphenylsilyl(cyclopentadiene). One or more of the following: (9-fluorenyl)zirconia, diphenylmethylenecyclopentadiene(2,7-di-tert-butyl-fluorenyl)zirconia, di-p-tolymethylenecyclopentadiene(2,7-di-tert-butyl-fluorenyl)zirconia, dimethylsilylbis(2-methyl-4-phenylindinyl)zirconia, dimethsilyl(N-tert-butylamino)(tetramethylcyclopentadienyl)titanium dichloride, dimethsilyl(N-tert-butylamino)(tetramethylcyclopentadienyl)dimethyltitanium, dimethsilyl(N-tert-butylamino)(fluorenyl)titanium dichloride, and (pentamethylcyclopentadienyl)trimethoxytitanium; The cocatalyst includes at least one of alkylaluminum, organoboron compounds, and alkylaluminoxanes, preferably one or more of methylaluminoxane, modified methylaluminoxane, ethylaluminoxane, trimethylaluminum, triethylaluminum, triisobutylaluminum, and tris(pentafluorophenyl)boron.

7. The method for preparing the flame-retardant polyolefin elastomer according to claim 5 or 6, characterized in that, The phosphorus-containing monomers include one or more of vinylphosphonic acid, divinylphenylphosphine oxide, acryloyloxyethyl dimethyl phosphate, allyl diphenylphosphine oxide, and vinyl diethyl phosphate. And / or, the α-olefin includes one or more of butene, hexene, and octene.

8. A type of leather, characterized in that, The raw material for the leather includes the flame-retardant polyolefin elastomer as described in any one of claims 1-4 or the flame-retardant polyolefin elastomer obtained by the preparation method described in any one of claims 5-7.

9. The leather according to claim 8, characterized in that, The raw materials for the leather also include one or more of the following: cross-linking agents, inorganic metal oxides, and antioxidants; Preferably, the mass ratio of the flame-retardant polyolefin elastomer to the crosslinking agent is 100:(0.1~5); the mass ratio of the flame-retardant polyolefin elastomer to the inorganic metal oxide is 100:(0.01~1); and the mass ratio of the flame-retardant polyolefin elastomer to the antioxidant is 100:(0.01~1). Preferably, the crosslinking agent comprises one or more of 2-hydroxyethyl methacrylate phosphate, tetraphenylbisphenol A diphosphate, bisphenol A bis(diphenyl) phosphate, triallyl isocyanate, trimethyl diphenyl phosphate, 2-ethylhexyl diphenyl phosphate, isodecyl diphenyl phosphate, tributoxyethyl phosphate, and tetraphenyl resorcinol diphosphate; the inorganic metal oxide comprises one or more of zinc oxide, magnesium oxide, and aluminum oxide; and the antioxidant comprises one or more of β-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate n-octadecyl alcohol, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1,2-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine, 2,2'-oxamido-bis[ethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)]propionate, and tris[2,4-di-tert-butylphenyl]phosphite.

10. A method for preparing leather according to claim 8 or 9, characterized in that, include: The raw materials for the leather are mixed and then cast to form a film. The film is then cross-linked by electron beam irradiation to obtain the leather.

Images