Gradient cross-linking foaming method based on high-performance polyurethane material

Abstract

The invention discloses a gradient cross-linking foaming method based on a high-performance polyurethane material. The gradient cross-linking foaming method comprises the following steps: S1, preparing raw materials; step S2, synthesizing a prepolymer; s3, gradient cross-linking foaming is carried out; step S4, carrying out post-treatment; the nano titanium dioxide and graphene composite material is added, so that the mechanical property and the thermal stability of the material are remarkably improved, meanwhile, the material is endowed with better aging resistance, and the service life is prolonged; through a staged heating foaming and curing process, gradient distribution of crosslinking density and a foam structure in the material is realized, and the gradient structure can remarkably improve the mechanical property and the heat insulation performance of the material, so that the material shows more excellent performance under complex working conditions, the tensile strength and the compression strength of the material are greatly improved, and the service life of the material is prolonged. The gradient cell structure obviously improves the heat insulation performance of the material, and the heat conductivity coefficient is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer material processing, and specifically relates to a gradient cross-linking foaming method based on high-performance polyurethane materials. Background Art

[0002] Polyurethane materials are widely used in various fields due to their excellent mechanical properties, wear resistance and chemical resistance. However, traditional polyurethane foam materials often have problems with uniform pore structure and single performance, making it difficult to meet the requirements of use under complex working conditions. In recent years, gradient structure materials have received widespread attention due to their unique performance distribution. Gradient cross-linking foaming technology can make the cross-linking density and pore structure inside the material show gradient changes, thereby giving the material better mechanical properties and functional characteristics. However, the existing technology lacks a polyurethane foaming method that can accurately control the formation of gradient structure.

[0003] Based on this, a gradient cross-linking foaming method based on high-performance polyurethane materials was designed. Summary of the Invention

[0004] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a gradient cross-linking foaming method based on high-performance polyurethane materials, which effectively solves the problems raised in the above background.

[0005] To achieve the above object, the present invention provides the following technical solution: a gradient cross-linking foaming method based on high-performance polyurethane material, comprising the following steps:

[0006] Step S1: Raw material preparation

[0007] Polyether polyol: 100 parts;

[0008] Polyisocyanate: 30-50 parts;

[0009] Chain extender: 5-15 parts;

[0010] Cross-linking agent: 2-8 parts;

[0011] Foaming agent: 5-15 parts;

[0012] Catalyst: 0.1-1 part;

[0013] Foam stabilizer: 0.5-2 parts;

[0014] Functional additives: 1-5 parts;

[0015] Step S2: Prepolymer synthesis

[0016] S2.1. Dehydrate the polyether polyol under vacuum at 100-120°C for 2-4 hours to remove moisture and prevent bubbles from forming during the foaming process;

[0017] S2.2. Cool the dehydrated polyether polyol to 50-80°C, add polyisocyanate, and stir to react for 1-3 hours to form a polyurethane prepolymer;

[0018] Step S3: Gradient cross-linking foaming

[0019] S3.1. Pour the prepolymer into a polytetrafluoroethylene mold and place it in an environmental chamber with a temperature of 60-80°C and a humidity of 50%-70%;

[0020] S3.2. Add chain extender, cross-linking agent, foaming agent, catalyst, foam stabilizer and functional additives to the mold, stir evenly and let it stand for 2-6 hours to allow the material to fully absorb water vapor from the environment;

[0021] S3.3. Place the mold into the foaming equipment and perform foaming according to the following gradient temperature increase program:

[0022] The first stage: heating to 100-120℃, keeping warm for 1-3 minutes to form the initial pore structure;

[0023] The second stage: heating to 130-150℃ and keeping warm for 2-5 minutes to further expand the pore structure and form a gradient distribution;

[0024] S3.4. Move the foamed mold to a vacuum oven at 100-180°C and cure according to the following gradient curing schedule:

[0025] The first stage: 100-120℃, keep warm for 2-4 hours, initial curing;

[0026] The second stage: 150-180℃, keep warm for 2-6 hours to complete cross-linking and curing to form a gradient cross-linking structure;

[0027] Step S4: Post-processing

[0028] S4.1. Remove the solidified foam material from the mold and cool it to room temperature;

[0029] S4.2. Perform surface treatment on the foam material to meet the requirements of different application scenarios.

[0030] Preferably, in step S1, the polyether polyol is one of polytetramethylene glycol and polypropylene glycol.

[0031] Preferably, in step S1, the polyisocyanate is one of toluene diisocyanate or diphenylmethane diisocyanate.

[0032] Preferably, in step S1, the chain extender is one of ethylene glycol and 1,4-butanediol.

[0033] Preferably, in step S1, the cross-linking agent is trimethylolpropane.

[0034] Preferably, in step S1, the foaming agent is a mixture of water and dichloromethane in a mass ratio of 1:3.

[0035] Preferably, in step S1, the catalyst is a mixture of triethylenediamine and amine ether in a mass ratio of 3:1.

[0036] Preferably, in step S1, the foam stabilizer is an organosilicon foam stabilizer.

[0037] Preferably, in step S1, the functional additive is a mixture of nano-scale titanium dioxide and graphene composite material, and the mass ratio of the nano-scale titanium dioxide to the graphene composite material is 1:1.

[0038] Preferably, in S2.2, the stirring reaction temperature is 60-80° C. and the stirring speed is 300-500 rpm to ensure uniform reaction.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The invention adds nano-scale titanium dioxide and graphene composite materials, which significantly improves the mechanical properties and thermal stability of the material, while giving the material better aging resistance and extending its service life;

[0041] Through a staged temperature-raising foaming and curing process, a gradient distribution of the material's internal cross-linking density and pore structure is achieved. This gradient structure can significantly improve the material's mechanical properties and thermal insulation properties, enabling it to exhibit better performance under complex working conditions, greatly improving the material's tensile strength and compressive strength. The gradient pore structure significantly improves the material's thermal insulation properties and reduces its thermal conductivity. DETAILED DESCRIPTION

[0042] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0043] The present invention provides a gradient cross-linking foaming method based on high-performance polyurethane material, comprising the following steps:

[0044] Step S1: Raw material preparation

[0045] Polyether polyol: 100 parts;

[0046] Polyisocyanate: 30-50 parts;

[0047] Chain extender: 5-15 parts;

[0048] Cross-linking agent: 2-8 parts;

[0049] Foaming agent: 5-15 parts;

[0050] Catalyst: 0.1-1 part;

[0051] Foam stabilizer: 0.5-2 parts;

[0052] Functional additives: 1-5 parts;

[0053] Step S2: Prepolymer synthesis

[0054] S2.1. Dehydrate the polyether polyol under vacuum at 100-120°C for 2-4 hours to remove moisture and prevent bubbles from forming during the foaming process;

[0055] S2.2. Cool the dehydrated polyether polyol to 50-80°C, add polyisocyanate, and stir to react for 1-3 hours to form a polyurethane prepolymer;

[0056] Step S3: Gradient cross-linking foaming

[0057] S3.1. Pour the prepolymer into a polytetrafluoroethylene mold and place it in an environmental chamber with a temperature of 60-80°C and a humidity of 50%-70%;

[0058] S3.2. Add chain extender, cross-linking agent, foaming agent, catalyst, foam stabilizer and functional additives to the mold, stir evenly and let it stand for 2-6 hours to allow the material to fully absorb water vapor from the environment;

[0059] S3.3. Place the mold into the foaming equipment and perform foaming according to the following gradient temperature increase program:

[0060] The first stage: heating to 100-120℃, keeping warm for 1-3 minutes to form the initial pore structure;

[0061] The second stage: heating to 130-150℃ and keeping warm for 2-5 minutes to further expand the pore structure and form a gradient distribution;

[0062] S3.4. Move the foamed mold to a vacuum oven at 100-180°C and cure according to the following gradient curing schedule:

[0063] The first stage: 100-120℃, keep warm for 2-4 hours, initial curing;

[0064] The second stage: 150-180℃, keep warm for 2-6 hours to complete cross-linking and curing to form a gradient cross-linking structure;

[0065] Step S4: Post-processing

[0066] S4.1. Remove the solidified foam material from the mold and cool it to room temperature;

[0067] S4.2. Perform surface treatment on the foam material to meet the requirements of different application scenarios.

[0068] In step S1 of this embodiment, the polyether polyol is one of polytetramethylene glycol and polypropylene glycol.

[0069] In step S1 of this embodiment, the polyisocyanate is one of toluene diisocyanate and diphenylmethane diisocyanate.

[0070] In step S1 of this embodiment, the chain extender is one of ethylene glycol and 1,4-butanediol.

[0071] In step S1 of this embodiment, the cross-linking agent is trimethylolpropane.

[0072] In step S1 of this embodiment, the foaming agent is a mixture of water and dichloromethane in a mass ratio of 1:3.

[0073] In step S1 of this embodiment, the catalyst is a mixture of triethylenediamine and amine ether in a mass ratio of 3:1.

[0074] In step S1 of this embodiment, the foam stabilizer is an organic silicon foam stabilizer.

[0075] In step S1 of this embodiment, the functional additive is a mixture of nano-scale titanium dioxide and graphene composite material, and the mass ratio of the nano-scale titanium dioxide to the graphene composite material is 1:1.

[0076] In S2.2 of this embodiment, the stirring reaction temperature is 60-80° C. and the stirring speed is 300-500 rpm to ensure uniform reaction.

[0077] Example 1:

[0078] A gradient cross-linking foaming method based on high-performance polyurethane material comprises the following steps:

[0079] Step S1: Raw material preparation

[0080] Polyether polyol: 100 parts;

[0081] Polyisocyanate: 30 parts;

[0082] Chain extender: 5 parts;

[0083] Cross-linking agent: 2 parts;

[0084] Foaming agent: 5 parts;

[0085] Catalyst: 0.1 part;

[0086] Foam stabilizer: 0.5 parts;

[0087] Functional additives: 1 part;

[0088] Step S2: Prepolymer synthesis

[0089] S2.1. Dehydrate the polyether polyol under vacuum at 100°C for 2 hours to remove moisture and prevent bubbles from forming during the foaming process.

[0090] S2.2. Cool the dehydrated polyether polyol to 50°C, add polyisocyanate, and stir to react for 1 hour to form a polyurethane prepolymer;

[0091] Step S3: Gradient cross-linking foaming

[0092] S3.1. Pour the prepolymer into a polytetrafluoroethylene mold and place it in an environmental chamber with a temperature of 60°C and a humidity of 50%;

[0093] S3.2. Add chain extender, cross-linking agent, foaming agent, catalyst, foam stabilizer and functional additives to the mold, stir evenly and let it stand for 2 hours to allow the material to fully absorb water vapor from the environment;

[0094] S3.3. Place the mold into the foaming equipment and perform foaming according to the following gradient temperature increase program:

[0095] The first stage: heating to 100°C and keeping warm for 1 minute to form the initial cellular structure;

[0096] The second stage: heating to 130°C and keeping it warm for 2 minutes to further expand the pore structure and form a gradient distribution;

[0097] S3.4. Move the foamed mold to a vacuum oven at 100°C and cure according to the following gradient curing schedule:

[0098] The first stage: 100℃, keep warm for 2 hours, initial curing;

[0099] The second stage: 150℃, keep warm for 2 hours to complete cross-linking and curing to form a gradient cross-linking structure;

[0100] Step S4: Post-processing

[0101] S4.1. Remove the solidified foam material from the mold and cool it to room temperature;

[0102] S4.2. Perform surface treatment on the foam material to meet the requirements of different application scenarios.

[0103] In step S1 of this embodiment, the polyether polyol is one of polytetramethylene glycol and polypropylene glycol.

[0104] In step S1 of this embodiment, the polyisocyanate is one of toluene diisocyanate and diphenylmethane diisocyanate.

[0105] In step S1 of this embodiment, the chain extender is one of ethylene glycol and 1,4-butanediol.

[0106] In step S1 of this embodiment, the cross-linking agent is trimethylolpropane.

[0107] In step S1 of this embodiment, the foaming agent is a mixture of water and dichloromethane in a mass ratio of 1:3.

[0108] In step S1 of this embodiment, the catalyst is a mixture of triethylenediamine and amine ether in a mass ratio of 3:1.

[0109] In step S1 of this embodiment, the foam stabilizer is an organic silicon foam stabilizer.

[0110] In step S1 of this embodiment, the functional additive is a mixture of nano-scale titanium dioxide and graphene composite material, and the mass ratio of the nano-scale titanium dioxide to the graphene composite material is 1:1.

[0111] In S2.2 of this embodiment, the stirring reaction temperature is 60° C. and the stirring speed is 300 rpm to ensure uniform reaction.

[0112] Example 2:

[0113] A gradient cross-linking foaming method based on high-performance polyurethane material comprises the following steps:

[0114] Step S1: Raw material preparation

[0115] Polyether polyol: 100 parts;

[0116] Polyisocyanate: 50 parts;

[0117] Chain extender: 15 parts;

[0118] Cross-linking agent: 8 parts;

[0119] Foaming agent: 15 parts;

[0120] Catalyst: 1 part;

[0121] Foam stabilizer: 2 parts;

[0122] Functional additives: 5 parts;

[0123] Step S2: Prepolymer synthesis

[0124] S2.1. Dehydrate the polyether polyol under vacuum at 120°C for 4 hours to remove moisture and prevent bubbles from forming during the foaming process.

[0125] S2.2. Cool the dehydrated polyether polyol to 80°C, add polyisocyanate, and stir to react for 3 hours to form a polyurethane prepolymer;

[0126] Step S3: Gradient cross-linking foaming

[0127] S3.1. Pour the prepolymer into a polytetrafluoroethylene mold and place it in an environmental chamber with a temperature of 80°C and a humidity of 70%;

[0128] S3.2. Add chain extender, cross-linking agent, foaming agent, catalyst, foam stabilizer and functional additives to the mold, stir evenly and let it stand for 6 hours to allow the material to fully absorb water vapor from the environment;

[0129] S3.3. Place the mold into the foaming equipment and perform foaming according to the following gradient temperature increase program:

[0130] The first stage: heating to 120℃ and keeping warm for 3 minutes to form the initial cellular structure;

[0131] The second stage: heating to 150°C and keeping it warm for 5 minutes to further expand the pore structure and form a gradient distribution;

[0132] S3.4. Move the foamed mold to a vacuum oven at 180°C and cure according to the following gradient curing schedule:

[0133] The first stage: 120℃, keep warm for 4 hours, initial curing;

[0134] The second stage: 180℃, keep warm for 6 hours to complete cross-linking and curing to form a gradient cross-linking structure;

[0135] Step S4: Post-processing

[0136] S4.1. Remove the solidified foam material from the mold and cool it to room temperature;

[0137] S4.2. Perform surface treatment on the foam material to meet the requirements of different application scenarios.

[0138] In step S1 of this embodiment, the polyether polyol is one of polytetramethylene glycol and polypropylene glycol.

[0139] In step S1 of this embodiment, the polyisocyanate is one of toluene diisocyanate and diphenylmethane diisocyanate.

[0140] In step S1 of this embodiment, the chain extender is one of ethylene glycol and 1,4-butanediol.

[0141] In step S1 of this embodiment, the cross-linking agent is trimethylolpropane.

[0142] In step S1 of this embodiment, the foaming agent is a mixture of water and dichloromethane in a mass ratio of 1:3.

[0143] In step S1 of this embodiment, the catalyst is a mixture of triethylenediamine and amine ether in a mass ratio of 3:1.

[0144] In step S1 of this embodiment, the foam stabilizer is an organic silicon foam stabilizer.

[0145] In step S1 of this embodiment, the functional additive is a mixture of nano-scale titanium dioxide and graphene composite material, and the mass ratio of the nano-scale titanium dioxide to the graphene composite material is 1:1.

[0146] In S2.2 of this embodiment, the stirring reaction temperature is 70° C. and the stirring speed is 400 rpm to ensure uniform reaction.

[0147] Example 3:

[0148] A gradient cross-linking foaming method based on high-performance polyurethane material comprises the following steps:

[0149] Step S1: Raw material preparation

[0150] Polyether polyol: 100 parts;

[0151] Polyisocyanate: 40 parts;

[0152] Chain extender: 10 parts;

[0153] Cross-linking agent: 5 parts;

[0154] Foaming agent: 10 parts;

[0155] Catalyst: 0.6 parts;

[0156] Foam stabilizer: 1.2 parts;

[0157] Functional additives: 3 parts;

[0158] Step S2: Prepolymer synthesis

[0159] S2.1. Dehydrate the polyether polyol under vacuum at 110°C for 3 hours to remove moisture and prevent bubbles from forming during the foaming process.

[0160] S2.2. Cool the dehydrated polyether polyol to 65°C, add polyisocyanate, and stir to react for 2 hours to form a polyurethane prepolymer;

[0161] Step S3: Gradient cross-linking foaming

[0162] S3.1. Pour the prepolymer into a polytetrafluoroethylene mold and place it in an environmental chamber with a temperature of 70°C and a humidity of 60%;

[0163] S3.2. Add chain extender, cross-linking agent, foaming agent, catalyst, foam stabilizer and functional additives to the mold, stir evenly and let it stand for 4 hours to allow the material to fully absorb water vapor from the environment;

[0164] S3.3. Place the mold into the foaming equipment and perform foaming according to the following gradient temperature increase program:

[0165] The first stage: heating to 110℃ and keeping warm for 2 minutes to form the initial cellular structure;

[0166] The second stage: heating to 140°C and keeping it warm for 3.5 minutes to further expand the pore structure and form a gradient distribution;

[0167] S3.4. Move the foamed mold to a vacuum oven at 140°C and cure according to the following gradient curing schedule:

[0168] The first stage: 110℃, keep warm for 3 hours, initial curing;

[0169] The second stage: 165℃, keep warm for 4 hours to complete cross-linking and curing to form a gradient cross-linking structure;

[0170] Step S4: Post-processing

[0171] S4.1. Remove the solidified foam material from the mold and cool it to room temperature;

[0172] S4.2. Perform surface treatment on the foam material to meet the requirements of different application scenarios.

[0173] In step S1 of this embodiment, the polyether polyol is one of polytetramethylene glycol and polypropylene glycol.

[0174] In step S1 of this embodiment, the polyisocyanate is one of toluene diisocyanate and diphenylmethane diisocyanate.

[0175] In step S1 of this embodiment, the chain extender is one of ethylene glycol and 1,4-butanediol.

[0176] In step S1 of this embodiment, the cross-linking agent is trimethylolpropane.

[0177] In step S1 of this embodiment, the foaming agent is a mixture of water and dichloromethane in a mass ratio of 1:3.

[0178] In step S1 of this embodiment, the catalyst is a mixture of triethylenediamine and amine ether in a mass ratio of 3:1.

[0179] In step S1 of this embodiment, the foam stabilizer is an organic silicon foam stabilizer.

[0180] In step S1 of this embodiment, the functional additive is a mixture of nano-scale titanium dioxide and graphene composite material, and the mass ratio of the nano-scale titanium dioxide to the graphene composite material is 1:1.

[0181] In S2.2 of this embodiment, the stirring reaction temperature is 70° C. and the stirring speed is 400 rpm to ensure uniform reaction.

[0182] Example 4:

[0183] A gradient cross-linking foaming method based on high-performance polyurethane material comprises the following steps:

[0184] Step S1: Raw material preparation

[0185] Polyether polyol: 100 parts;

[0186] Polyisocyanate: 35 parts;

[0187] Chain extender: 6 parts;

[0188] Cross-linking agent: 3 parts;

[0189] Foaming agent: 6 parts;

[0190] Catalyst: 0.3 parts;

[0191] Foam stabilizer: 0.8 parts;

[0192] Functional additives: 2 parts;

[0193] Step S2: Prepolymer synthesis

[0194] S2.1. Dehydrate the polyether polyol under vacuum at 105°C for 2.5 hours to remove moisture and prevent bubbles from forming during the foaming process.

[0195] S2.2. Cool the dehydrated polyether polyol to 55°C, add polyisocyanate, and stir to react for 1.5 hours to form a polyurethane prepolymer;

[0196] Step S3: Gradient cross-linking foaming

[0197] S3.1. Pour the prepolymer into a polytetrafluoroethylene mold and place it in an environmental chamber with a temperature of 65°C and a humidity of 55%.

[0198] S3.2. Add chain extender, cross-linking agent, foaming agent, catalyst, foam stabilizer and functional additives to the mold, stir evenly and let it stand for 3 hours to allow the material to fully absorb water vapor from the environment;

[0199] S3.3. Place the mold into the foaming equipment and perform foaming according to the following gradient temperature increase program:

[0200] The first stage: heating to 105°C and keeping warm for 2 minutes to form the initial cellular structure;

[0201] The second stage: heating to 135°C and keeping warm for 3 minutes to further expand the pore structure and form a gradient distribution;

[0202] S3.4. Move the foamed mold to a vacuum oven at 130°C and cure according to the following gradient curing schedule:

[0203] The first stage: 105℃, keep warm for 2.5 hours, initial curing;

[0204] The second stage: 155℃, keep warm for 3 hours to complete cross-linking and curing to form a gradient cross-linking structure;

[0205] Step S4: Post-processing

[0206] S4.1. Remove the solidified foam material from the mold and cool it to room temperature;

[0207] S4.2. Perform surface treatment on the foam material to meet the requirements of different application scenarios.

[0208] In step S1 of this embodiment, the polyether polyol is one of polytetramethylene glycol and polypropylene glycol.

[0209] In step S1 of this embodiment, the polyisocyanate is one of toluene diisocyanate and diphenylmethane diisocyanate.

[0210] In step S1 of this embodiment, the chain extender is one of ethylene glycol and 1,4-butanediol.

[0211] In step S1 of this embodiment, the cross-linking agent is trimethylolpropane.

[0212] In step S1 of this embodiment, the foaming agent is a mixture of water and dichloromethane in a mass ratio of 1:3.

[0213] In step S1 of this embodiment, the catalyst is a mixture of triethylenediamine and amine ether in a mass ratio of 3:1.

[0214] In step S1 of this embodiment, the foam stabilizer is an organic silicon foam stabilizer.

[0215] In step S1 of this embodiment, the functional additive is a mixture of nano-scale titanium dioxide and graphene composite material, and the mass ratio of the nano-scale titanium dioxide to the graphene composite material is 1:1.

[0216] In S2.2 of this embodiment, the stirring reaction temperature is 65° C. and the stirring speed is 350 rpm to ensure uniform reaction.

[0217] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0218] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A gradient cross-linking foaming method based on high-performance polyurethane materials, characterized in that: The following steps are involved: Step S1: Raw material preparation Polyether polyol: 100 parts; Polyisocyanate: 30-50 parts; Chain extender: 5-15 parts; Cross-linking agent: 2-8 parts; Foaming agent: 5-15 parts; Catalyst: 0.1-1 part; Foam stabilizer: 0.5-2 parts; Functional additives: 1-5 parts; Step S2: Prepolymer synthesis S2.

1. Dehydrate the polyether polyol under vacuum at 100-120°C for 2-4 hours to remove moisture and prevent bubbles from forming during the foaming process; S2.

2. Cool the dehydrated polyether polyol to 50-80°C, add polyisocyanate, and stir to react for 1-3 hours to form a polyurethane prepolymer; Step S3: Gradient cross-linking foaming S3.

1. Pour the prepolymer into a polytetrafluoroethylene mold and place it in an environmental chamber with a temperature of 60-80°C and a humidity of 50%-70%; S3.

2. Add chain extender, cross-linking agent, foaming agent, catalyst, foam stabilizer and functional additives to the mold, stir evenly and let it stand for 2-6 hours to allow the material to fully absorb water vapor from the environment; S3.

3. Place the mold into the foaming equipment and perform foaming according to the following gradient temperature increase program: The first stage: heating to 100-120℃, keeping warm for 1-3 minutes to form the initial pore structure; The second stage: heating to 130-150℃ and keeping warm for 2-5 minutes to further expand the pore structure and form a gradient distribution; S3.

4. Move the foamed mold to a vacuum oven at 100-180°C and cure according to the following gradient curing schedule: The first stage: 100-120℃, keep warm for 2-4 hours, initial curing; The second stage: 150-180℃, keep warm for 2-6 hours to complete cross-linking and curing to form a gradient cross-linking structure; Step S4: Post-processing S4.

1. Remove the solidified foam material from the mold and cool it to room temperature; S4.

2. Perform surface treatment on the foam material to meet the requirements of different application scenarios.

2. A gradient cross-linking foaming method based on high-performance polyurethane material according to claim 1, characterized in that: In the step S1, the polyether polyol is one of polytetramethylene glycol and polypropylene glycol.

3. The gradient cross-linking foaming method based on high-performance polyurethane material according to claim 1, characterized in that: In the step S1, the polyisocyanate is one of toluene diisocyanate and diphenylmethane diisocyanate.

4. The gradient cross-linking foaming method based on high-performance polyurethane material according to claim 1, characterized in that: In step S1, the chain extender is one of ethylene glycol and 1,4-butanediol.

5. The gradient cross-linking foaming method based on high-performance polyurethane material according to claim 1, characterized in that: In the step S1, the cross-linking agent is trimethylolpropane.

6. The gradient cross-linking foaming method based on high-performance polyurethane material according to claim 1, characterized in that: In step S1, the foaming agent is a mixture of water and dichloromethane in a mass ratio of 1:

3.

7. The gradient cross-linking foaming method based on high-performance polyurethane material according to claim 1, characterized in that: In step S1, the catalyst is a mixture of triethylenediamine and amine ether in a mass ratio of 3:

1.

8. The gradient cross-linking foaming method based on high-performance polyurethane material according to claim 1, characterized in that: In step S1, the foam stabilizer is an organic silicon foam stabilizer.

9. The gradient cross-linking foaming method based on high-performance polyurethane material according to claim 1, characterized in that: In step S1, the functional additive is a mixture of nano-scale titanium dioxide and graphene composite material, and the mass ratio of the nano-scale titanium dioxide to the graphene composite material is 1:

1.

10. The gradient cross-linking foaming method based on high-performance polyurethane material according to claim 1, characterized in that: In S2.2, the stirring reaction temperature is 60-80° C. and the stirring speed is 300-500 rpm to ensure uniform reaction.