A polyurethane composition for a polyurethane cushioning block, a polyurethane cushioning block, and a method for preparing and use thereof

Abstract

The present application relates to a kind of polyurethane composition for polyurethane cushion block and its preparation method and application.The polyurethane composition includes isocyanate component and isocyanate reactive component, the isocyanate reactive component includes polyether polyol 1, polyether polyol 2, polymer polyol, flame retardant, chain extender, crosslinking agent, catalyst, blowing agent, surfactant;Wherein, the polyether polyol 1, polyether polyol 2 and polymer polyol can accurately control the balance of strength and elastic performance of polyurethane cushion block by accurate collocation.The polyurethane cushion block of the present application can meet the complex performance requirements such as compression resistance and flame resistance of new energy vehicle battery side, can reduce the impact of vehicle collision on battery pack, greatly reduce the intrusion amount of impact on battery pack, and reduce the risk of thermal runaway when battery pack collides, for stable manufacturing of new energy vehicle battery pack side cushion block.

Description

Technical Field

[0001] This invention relates to the field of polyurethane materials, particularly polyurethane compositions for use in new energy battery buffer blocks, as well as polyurethane buffer blocks, their preparation methods, and applications. Background Technology

[0002] New energy is one of the strategic emerging industries planned by my country, and it is of great significance to my country's green and sustainable development. The prospects for new energy development are very promising.

[0003] Against the backdrop of new energy vehicles pursuing longer driving ranges and higher energy densities, fires caused by thermal runaway due to impact damage to power batteries are becoming increasingly frequent. On April 22, 2023, a new energy vehicle undergoing repairs at an auto service center caught fire. The vehicle had previously suffered a severe impact to its chassis, resulting in extensive deformation of the left rear outer casing and cooling plate of the power battery pack. Under this compressed state, the internal structure of the battery pack short-circuited after a period of time, ultimately igniting the fire.

[0004] Therefore, the impact load buffering performance and flame retardant performance of next-generation high-energy-density power batteries are key technical issues that urgently need to be addressed, limiting the development of new energy vehicles. In particular, the development of side impact buffer materials for battery packs should meet performance indicators such as high strength, high toughness, high flame retardancy, high inter-range strength, and high elasticity. It should also achieve rapid and automated risk mitigation to reduce the impact of vehicle collisions on the battery pack, significantly reduce the intrusion of impacts into the battery pack, reduce the risk of thermal runaway during a collision, improve side impact resistance, and thus further enhance the safety of new energy vehicles.

[0005] Currently, China lacks domestic technology for polyurethane buffer materials for new energy batteries. Existing patents such as CN202121961499.4 and CN201921870473.1 are improvements on macroscopic buffer structures, but lack enhancements to the material's intrinsic performance.

[0006] Based on a comprehensive analysis of the material performance requirements and lightweight demands of new energy batteries, the polyurethane buffer block material for new energy batteries should simultaneously possess the characteristics of rigid foam structure and elastomer. In other words, it must have a certain strength and compressive strength to resist impact loads, and also have a certain degree of deformability to absorb impact energy. This presents a significant contradiction with the performance characteristics of polyurethane foam material itself. Furthermore, it must also have high flame retardant properties. Summary of the Invention

[0007] To address the problems existing in the prior art, the present invention provides a polyurethane composition for polyurethane battery buffer blocks, and a polyurethane buffer block made therefrom. This polyurethane battery buffer block combines the characteristics of rigid foam and elastomer, exhibiting lightweight, excellent mechanical, and flame-retardant properties.

[0008] Another object of the present invention is to provide a method for preparing such a polyurethane buffer block and its application.

[0009] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0010] A polyurethane composition for a polyurethane cushioning block is obtained from an isocyanate component and an isocyanate reactive component, wherein the isocyanate reactive component comprises polyether polyol 1, polyether polyol 2, polymer polyol, flame retardant, chain extender, crosslinking agent, catalyst, foaming agent, and surfactant; wherein

[0011] The polyether polyol 1 has an average functionality of 2-5, preferably 3-4, and a hydroxyl value of 400-1100 mgKOH / g, for example, 400 mgKOH / g, 500 mgKOH / g, 00 mgKOH / g, 700 mgKOH / g, etc.

[0012] mgKOH / g, 800mgKOH / g, 900mgKOH / g, 1000mgKOH / g, 1100mgKOH / g, etc., preferably 500-900mgKOH / g; obtained by reacting ethylene oxide and optionally propylene oxide, wherein the ethylene oxide content is 70-100%, such as 70%, 75%, 80%, 82%, 85%, 90%, 95%, 100%, etc., preferably 80-100wt%, based on the total mass of propylene oxide and ethylene oxide as 100%. The polyether polyol 1 is a class of compounds formed by the polymerization of epoxides from polyols. Examples of initiators include, but are not limited to, ethylene glycol, propylene glycol, 1,4-butanediol, dipropylene glycol, diethylene glycol, triethylene glycol, bisphenol A, glycerol, trimethylolpropane, diethanolamine, triethanolamine, ethylenediamine, toluenediamine, pentaerythritol, sorbitol, xylitol, sucrose, or mixtures thereof. The epoxide monomer can be block addition or random addition, preferably random addition.

[0013] The polyether polyol 2 has an average functionality of 1.5 to 3.5, preferably 2, and a hydroxyl value of 30 to 200 mgKOH / g, such as 40 mgKOH / g, 50 mgKOH / g, 60 mgKOH / g, 70 mgKOH / g, 80 mgKOH / g, 90 mgKOH / g, 100 mgKOH / g, 130 mgKOH / g, 150 mgKOH / g, 180 mgKOH / g, 200 mgKOH / g, etc., preferably 50 to 100 mgKOH / g; it is formed by ring-opening copolymerization of tetrahydrofuran and propylene oxide.

[0014] The polymeric polyol, namely the graft copolymer polyether polyol, has an average functionality of 2 to 4.5, such as 2, 2.5, 3, 3.5, 4, 4.5, etc., preferably 3, and a hydroxyl value of 10 to 80 mgKOH / g, such as 10 mgKOH / g, 15 mgKOH / g, 20 mgKOH / g, 25 mgKOH / g, 30 mgKOH / g, 35 mgKOH / g, 40 mgKOH / g, 45 mgKOH / g, 50 mgKOH / g, 60 mgKOH / g, 70 mgKOH / g, 80 mgKOH / g, etc., preferably 15 to 50 mgKOH / g, and a solid content of 20 to 50 wt%, such as 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, etc., preferably 25 to 45 wt%. The polymer polyol refers to a type of graft copolymer polyol obtained by reacting polyether polyol and vinyl monomer. The polyether polyol can be polyoxyethylene polyol, polyoxypropylene polyol, polyoxyethylene-propylene oxide copolymer polyol, etc., which are commonly used in the art. The vinyl monomer can be acrylonitrile, styrene, vinylidene chloride, hydroxyalkyl acrylate and alkyl acrylate, etc., preferably acrylonitrile and / or styrene.

[0015] Based on the total mass of the isocyanate reactive components, the amount (A) of polyether polyol 1 is 15% to 25%, for example, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, etc.; the amount (B) of polyether polyol 2 is 20% to 41%, for example, 20%, 21%, 22%, 23%, 24%, 25%, 28%, 30%, 31%, 33%, 35%, 38%, 40%, 41%, etc.; and the amount (C) of polymer polyol is 8.7% to 16%, for example, 8.7%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, etc.

[0016] In a preferred embodiment, the amounts of polyether polyol 1 (A), polyether polyol 2 (B), and polymer polyol (C) simultaneously satisfy the following relationship:

[0017]

[0018] In some specific embodiments, the isocyanate component refers to a class of compounds having an isocyanate group, examples of which include, but are not limited to, toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), naphthalene diisocyanate (DI), terephthalic diisocyanate (PPDI), 1,4-cyclohexane diisocyanate (CHDI), phenylenediamine diisocyanate (XDI), cyclohexane diisocyanate (XDI), trimethyl-1,6-hexamethylene diisocyanate (TMHDI), tetramethyl-m-phenylenediamine diisocyanate (TMXDI), norbornane diisocyanate (NBDI), dimethylbiphenyl diisocyanate (TODI), methylcyclohexyl diisocyanate (HTDI), etc., as well as prepolymers, modified products, polymers, etc., of these monomers. These isocyanate compounds can be used alone or in combination. Preferably, the isocyanate component NCO content is 20-34 wt%, such as 20 wt%, 22 wt%, 25 wt%, 28 wt%, 30 wt%, 32 wt%, 34 wt%, etc., and more preferably 31 wt%.

[0019] In some specific embodiments, the catalyst is a class of compounds that are catalytically active to isocyanates and active hydrogen atoms. Examples include, but are not limited to, triethylamine, tributylamine, triethylenediamine, N-ethylmorpholine, N,N,N',N'-tetramethyl-ethylenediamine, pentamethyldiethylene-triamine, N,N-methylaniline, N,N-dimethylaniline, tin(II) acetate, tin(II) octoate, tin ethylhexanoate, tin laurate, dibutyltin oxide, dibutyltin dichloride, dibutyltin diacetate, dibutyltin maleate, dioctyltin diacetate, etc., which can be used alone or in combination.

[0020] In some specific implementations, the foaming agent may be selected from commonly used physical foaming agents and chemical foaming agents in the art, including but not limited to one or more of water, monochlorodifluoromethane, monochloromonofluoromethane, dichlorodifluoromethane, trichlorofluoromethane, butane, pentane, cyclopentane, hexane, cyclohexane, heptane, air, CO2 and N2, preferably water.

[0021] In some specific embodiments, the surfactant includes, but is not limited to, for example, a polysiloxane-olefin oxide block copolymer as its main structure, and can be used alone or in combination. For example, the surfactant has an AB-type linear block structure, an ABA-type linear block structure, etc.

[0022] In some specific implementations, the chain extender may be a chain extender commonly used in the art, such as diols, diamines, diphenols, etc. Examples include, but are not limited to, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, butanediol, cyclohexanediol, methylamine, ethylamine, hydrogenated bisphenol A, hydroquinone, etc. These chain extenders may be used alone or in combination.

[0023] In some specific implementations, the crosslinking agent can be a commonly used crosslinking agent in the art, such as polyols, polyamines, etc. Examples include, but are not limited to, trimethylolpropane, glycerol, pentaerythritol, diethanolamine, triethanolamine, ethylenediamine, phenylenediamine, sorbitol, etc. These crosslinking agents can be used alone or in combination.

[0024] In some specific implementation schemes, the flame retardant may include, but is not limited to, halogenated phosphate flame retardants, phosphate flame retardants, halogenated hydrocarbons and other halogenated flame retardants, melamine and its salts, reactive flame retardants, inorganic flame retardants, etc., and these flame retardants may be used alone or in combination.

[0025] In some specific embodiments, the molar ratio of isocyanate groups in the isocyanate component to active hydrogen atoms in the isocyanate reactive component is 90 to 120:100, such as 90:100, 95:100, 100:100, 105:100, 110:100, 115:100, 120:100, etc., preferably 95 to 110:100.

[0026] In a preferred embodiment, the mass percentage of each component, based on the total mass of the isocyanate reactive components, is as follows:

[0027] The amount of polyether polyol 1 used is 15-25%, such as 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, etc.

[0028] The amount of polyether polyol 2 used is 20% to 41%, for example, 20%, 21%, 22%, 23%, 24%, 25%, 28%, 30%, 33%, 35%, 37%, 40%, 41%, etc.;

[0029] The amount of polymer polyol used is 8.7% to 16%, such as 8.7%, 9%, 9.5%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, etc.;

[0030] The amount of foaming agent used is 0.1% to 1%, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc.;

[0031] Flame retardant dosage ranges from 10% to 36%, for example, 10%, 12%, 15%, 18%, 20%, 23%, 25%, 28%, 30%, 32%, 35%, 36%, etc.

[0032] The catalyst dosage is 0.1% to 0.8%, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, etc.;

[0033] The chain extender dosage is 5-10%, for example, 5%, 6%, 7%, 8%, 9%, 10%, etc.;

[0034] The crosslinking agent dosage is 1-8%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, etc.;

[0035] The amount of surfactant used is 0.1% to 0.8%, such as 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, etc.

[0036] In this invention, a polyurethane composition comprising the isocyanate component, polyether polyol 1, polyether polyol 2, polymer polyol, flame retardant, chain extender, crosslinking agent, catalyst, foaming agent, surfactant, etc., is used to prepare polyurethane foam. When used, it exhibits excellent flame retardant properties and meets the special compression resistance requirements of new energy vehicle battery packs. It can reduce the impact of vehicle collisions on the battery pack, greatly reduce the amount of impact intrusion into the battery pack, and reduce the risk of thermal runaway when the battery pack is involved in a collision.

[0037] In another aspect of the present invention, a method for using the polyurethane composition to prepare a polyurethane buffer block includes the following steps:

[0038] 1) Mix and stir the isocyanate components evenly and set aside; mix and stir the isocyanate reactive components evenly and set aside.

[0039] 2) The isocyanate component and the isocyanate reactive component are mixed evenly by the equipment and then injected into the buffer block mold for reaction. After the reaction is completed, the mold is opened to obtain the polyurethane buffer block.

[0040] In another aspect of the present invention, the polyurethane buffer block prepared by the aforementioned method has a density of 600–900 kg / m³. 3 Preferred weight: 700-800 kg / m³ 3 The pressure of the casting machine is 100-180 bar, preferably 130-170 bar; the mold temperature is 30-90℃, preferably 40-60℃; and the holding time is 3-20 minutes, preferably 5-15 minutes.

[0041] In another aspect of the present invention, the polyurethane buffer block prepared by the aforementioned method or the application of the aforementioned polyurethane buffer block in new energy vehicles, especially in power battery packaging materials.

[0042] Regarding the specific components involved in the polyurethane battery buffer block described in this invention, such as polyols and additives, unless otherwise specified, they can be used alone or in combination. Furthermore, the raw materials, processes, methods, parameters, etc., required for the preparation of each component, unless otherwise stated or described, can refer to commonly used techniques in the art without affecting the implementation of this invention. Examples include the preparation of polyether polyols, polyester polyols, polymer polyols, and polyurethane battery buffer blocks.

[0043] Unless otherwise specified, the term "hydroxyl value" in this invention refers to the average hydroxyl value of the component.

[0044] In this invention, polyether polyol 1 introduces hard segments into the molecular structure, providing strength to the polyurethane foam under low early deformation; polyether polyol 2 is a ring-opening polymerization product of tetrahydrofuran and propylene oxide, providing high elasticity to the polyurethane foam; the polymer polyol is glycerol-initiated, polymerized with propylene oxide, end-capped with ethylene oxide, and grafted with styrene and acrylonitrile, providing additional space for molecular chain movement and intermolecular interaction forces, thus improving both the elasticity and strength of the polyurethane foam.

[0045] Based on the specific mechanical performance requirements of battery buffer blocks for new energy vehicles: the compressive strength is 6-9 MPa under 10% deformation, 14-18 MPa under 30% deformation, and 30-36 MPa under 50% deformation. Although the individual strength values ​​are within the range of rigid foam, they are clearly different from the performance trends of conventional polyurethane rigid foam materials when considered together.

[0046] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0047] The polyurethane composition of this invention can be used to prepare polyurethane buffer blocks. By controlling the amount of each component, a balance between the strength and elastic properties of the polyurethane foam buffer block can be achieved, simultaneously and fully meeting the aforementioned mechanical performance requirements as well as complex performance requirements such as high flame retardancy. This reduces the impact of vehicle collisions on the battery pack, significantly reduces the intrusion of impact into the battery pack, and lowers the risk of thermal runaway during a collision. Detailed Implementation

[0048] The specific implementation scheme of this method is further illustrated below with examples. However, the present invention is not limited to the listed embodiments, but should also include any other well-known modifications within the scope of the claims of the present invention.

[0049] The raw materials used in the examples and comparative examples are as follows:

[0050] Isocyanate component, WANNATE 82681, NCO content is 31wt%, viscosity at 25℃ is 200mPa·s, Wanhua Chemical;

[0051] Polyether polyol 1-1, glycerol-based, homopolymerized with ethylene oxide, hydroxyl value 500 mg KOH / g;

[0052] Polyether polyols 1-2, pentaerythritol-based, random copolymerization of propylene oxide and ethylene oxide, ethylene oxide content 85wt%, hydroxyl value 700mgKOH / g;

[0053] Polyether polyol 1-3, average functionality 3.5, pentaerythritol and glycerol co-initiated, random copolymerization of propylene oxide and ethylene oxide, ethylene oxide content 80wt%, hydroxyl value 900mgKOH / g;

[0054] Polyether polyol 2-1, with an average functionality of 2, is formed by ring-opening copolymerization of tetrahydrofuran and propylene oxide, and has a hydroxyl value of 50 mgKOH / g.

[0055] Polyether polyol 2-2, with an average functionality of 2, is formed by ring-opening copolymerization of tetrahydrofuran and propylene oxide, and has a hydroxyl value of 70 mgKOH / g.

[0056] Polyether polyol 2-3, average functionality 2, is formed by ring-opening copolymerization of tetrahydrofuran and propylene oxide, hydroxyl value 100mgKOH / g;

[0057] Polymer polyol 1-1, starting with glycerol, hydroxyl value 15 mg KOH / g, solid content 25 wt%;

[0058] Polymer polyol 1-2, starting with trimethylolpropane, hydroxyl value 35 mgKOH / g, solid content 30 wt%;

[0059] Polymer polyols 1-3, starting with glycerol, hydroxyl value 50 mg KOH / g, solid content 45 wt%;

[0060] Flame retardant 1, TCPP, Jiahua Chemical;

[0061] Flame retardant 2, expanded graphite, and marine carbon materials;

[0062] Surfactant, BM023, Wanhua Chemical;

[0063] Catalyst, KC152, Wanhua Chemical;

[0064] Chain extender, ethylene glycol, CNOOC Shell;

[0065] Crosslinking agent, glycerin, Asahikawa Chemical;

[0066] Foaming agent, water.

[0067] Preparation methods of polyurethane buffer block samples in the examples and comparative examples:

[0068] Step 1: Control the temperature of the isocyanate component and the isocyanate reactive component to 25℃ respectively;

[0069] Step two: The isocyanate component and the isocyanate reactive component are injected into the buffer block mold using a high-pressure casting machine to react. After the reaction is complete, the mold is opened to obtain a polyurethane buffer block. The density of the buffer block is 750±5 kg / m³. 3 The pressure of the high-pressure casting machine is 150 bar, the mold temperature is 55℃, and the holding time is 6 minutes.

[0070] The raw materials used in the examples and comparative examples are listed in Tables 1 and 2.

[0071] Table 1 (Parts by weight)

[0072] Example 1 Example 2 Example 3 Example 4 Example 5 Polyether polyol 1-1 15 24 Polyether polyol 1-2 25 20 Polyether polyol 1-3 18.3 Polyether polyol 2-1 20 37 Polyether polyol 2-2 41 30 Polyether polyol 2-3 22 Polymer polyol 1-1 8.7 14.9 Polymer polyol 1-2 16 12.2 Polymer polyols 1-3 10 foaming agent 1 0.5 0.1 0.8 0.6 Flame retardant 1 30.7 7.3 30 1 18.6 Flame retardant 2 5 4 6 9 5 catalyst 0.8 0.1 0.6 0.7 0.4 Chain extender 10 5 6.3 7.25 8 Crosslinking agent 8 1 6 4.75 5 surfactants 0.8 0.1 0.7 0.6 0.2 Molar ratio of NCO to active hydrogen atoms 95：100 110：100 100：100 102.3：100 108.5：100

[0073] Table 2 (Parts by weight)

[0074]

[0075]

[0076] The following criteria were used to test the buffer blocks obtained in the examples and comparative examples:

[0077] Density testing standard: ISO 845;

[0078] Compression performance testing standard: GB / T 2569;

[0079] Flame retardant performance testing standard: UL94, thickness 4mm;

[0080] The buffer blocks obtained in the examples and comparative examples were tested, and the test results are listed in the table below.

[0081] Table 3 Performance of Examples and Comparative Examples

[0082]

[0083] As can be seen from the examples and comparative examples, the examples exhibit superior flame-retardant properties and meet the compression performance requirements of various levels of new energy vehicle battery packs. This reduces the impact of vehicle collisions on the battery pack, significantly decreases the intrusion of impacts into the battery pack, and reduces the risk of thermal runaway during a collision. The comparative examples, however, fail to meet these requirements.

[0084] The present invention has been illustrated with the above embodiments to explain the detailed method of the present invention. However, the present invention is not limited to the detailed method described above, that is, it does not mean that the present invention must rely on the detailed method described above to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A polyurethane composition for a polyurethane buffer block, comprising an isocyanate component and an isocyanate reactive component, characterized in that, The isocyanate reactive component comprises polyether polyol 1, polyether polyol 2, polymer polyol, flame retardant, chain extender, crosslinking agent, catalyst, foaming agent, and surfactant; wherein The polyether polyol 1 has an average functionality of 2-5 and a hydroxyl value of 400-1100 mgKOH / g; it is obtained by reacting ethylene oxide and optionally propylene oxide, with an ethylene oxide content of 70-100%, based on the total mass of propylene oxide and ethylene oxide being 100%. The polyether polyol 2 has an average functionality of 1.5~3.5 and a hydroxyl value of 30~200 mgKOH / g; it is formed by ring-opening copolymerization of tetrahydrofuran and propylene oxide. Polymer polyols, namely graft copolymer polyether polyols, have an average functionality of 2-4.5; a hydroxyl value of 10-80 mgKOH / g; and a solid content of 20-50 wt%. The amount of polyether polyol 1 used is A 15%~25%, the amount of polyether polyol 2 used is B 20%~41%, and the amount of polymer polyol used is C 8.7%~16%; The molar ratio of isocyanate groups in the isocyanate component to active hydrogen atoms in the isocyanate reactive component of the polyurethane composition is 90~120:

100.

2. The polyurethane composition for polyurethane buffer blocks according to claim 1, characterized in that, The polyether polyol 1 has an average functionality of 3-4 and a hydroxyl value of 500-900 mgKOH / g; it is obtained by reacting ethylene oxide and optionally propylene oxide, with an ethylene oxide content of 80-100 wt%, based on the total mass of propylene oxide and ethylene oxide being 100%. The polyether polyol 2 has an average functionality of 2 and a hydroxyl value of 50~100mgKOH / g; Polymer polyol, average functionality 3; hydroxyl value 15~50mgKOH / g; solid content 25~45wt%.

3. The polyurethane composition for polyurethane buffer blocks according to claim 1, characterized in that, The catalyst is a class of compounds that have catalytic activity towards isocyanates and active hydrogen atoms.

4. The polyurethane composition for polyurethane buffer blocks according to claim 3, characterized in that, The catalyst is selected from at least one of triethylamine, tributylamine, triethylenediamine, N-ethylmorpholine, N,N,N',N'-tetramethyl-ethylenediamine, pentamethyldiethylene-triamine, N,N-methylaniline, N,N-dimethylaniline, tin(II) acetate, tin(II) octoate, tin ethylhexanoate, tin laurate, dibutyltin oxide, dibutyltin dichloride, dibutyltin diacetate, dibutyltin maleate, and dioctyltin diacetate.

5. The polyurethane composition for polyurethane buffer blocks according to claim 1, characterized in that, The surfactant is selected from at least one of polysiloxane-oxidized olefin block copolymers.

6. The polyurethane composition for polyurethane buffer blocks according to claim 1, characterized in that, The foaming agent is either a physical foaming agent or a chemical foaming agent.

7. The polyurethane composition for polyurethane buffer blocks according to claim 6, characterized in that, The foaming agent is selected from one or more of water, monochlorofluoromethane, monochlorodifluoromethane, dichlorodifluoromethane, trichlorofluoromethane, butane, hexane, cyclohexane, pentane, cyclopentane, heptane, N2, CO2, and air.

8. The polyurethane composition for polyurethane buffer blocks according to claim 7, characterized in that, The foaming agent is water.

9. The polyurethane composition for polyurethane buffer blocks according to claim 1, characterized in that, The crosslinking agent is any one of polyols and polyamines; and / or The chain extender is at least one selected from diols, diamines, and diphenols; and / or The flame retardant is selected from at least one of the following: halogenated phosphate flame retardants, phosphate flame retardants, halogenated hydrocarbons and other halogenated flame retardants, melamine and its salts, reactive flame retardants, and inorganic flame retardants.

10. The polyurethane composition for a polyurethane buffer block according to claim 9, characterized in that, The crosslinking agent is selected from at least one of trimethylolpropane, glycerol, pentaerythritol, diethanolamine, triethanolamine, ethylenediamine, phenylenediamine, and sorbitol; and / or The chain extender is selected from at least one of ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, butanediol, cyclohexanediol, hydrogenated bisphenol A, and hydroquinone.

11. The polyurethane composition for polyurethane buffer blocks according to any one of claims 1 to 10, characterized in that, Based on the total mass of the isocyanate reactive component, the isocyanate reactive component comprises: Polyether polyol 115~25%; Polyether polyols 220~41%; Polymer polyols: 8.7-16%; Foaming agent 0.1~1%; Flame retardant 10~36%; Catalyst 0.1~0.8%; Chain extender 5-10%; Crosslinking agent 1~8%; Surfactant 0.1~0.8%.

12. The polyurethane composition for polyurethane buffer blocks according to claim 11, characterized in that, The molar ratio of isocyanate groups in the isocyanate component to active hydrogen atoms in the isocyanate reactive component of the polyurethane composition is 95~110:

100.

13. A method for preparing a polyurethane buffer block, characterized in that, Includes the following steps: 1) The polyurethane buffer block according to any one of claims 1 to 12 is mixed and stirred evenly with the isocyanate component and the isocyanate reactive component in the polyurethane composition and then set aside for later use. 2) The isocyanate component and the isocyanate reactive component are mixed evenly by the equipment and then injected into the buffer block mold for reaction. After the reaction is completed, the mold is opened to obtain the polyurethane buffer block.

14. A polyurethane buffer block prepared by the method of claim 13, characterized in that, The polyurethane buffer block has a density of 600~900 kg / m3, the casting machine pressure is 100~180 bar, the mold temperature is 30~90℃, and the holding time is 3~20 minutes.

15. The polyurethane buffer block according to claim 14, characterized in that, The polyurethane buffer block has a density of 700~800 kg / m3, the casting machine pressure is 130~170 bar, the mold temperature is 40~60℃, and the holding time is 5~15 minutes.

16. The application of the polyurethane buffer block prepared by the method of claim 13 or the polyurethane buffer block of claim 14 or 15 in new energy vehicles.

17. The application according to claim 16, characterized in that, Application in power battery packaging materials.

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