Automotive polyurethane foam with high connection strength and preparation method thereof

Abstract

The invention relates to automotive polyurethane foam with high connection strength and a preparation method thereof, and relates to the technical field of foam, and the automotive polyurethane foam comprises the following components in parts by mass: 40-60 parts of polyether modified bio-based polyol, 30-50 parts of isocyanate, 8-12 parts of a chain extender, 3-5 parts of a compound foaming agent, 0.5-1.5 parts of a catalyst, 1-3 parts of a surfactant and 3-6 parts of water. The preparation method comprises the following steps: adding a surfactant, a chain extender and water into polyether modified bio-based polyol, and stirring to obtain a polyol premix; adding isocyanate into the polyol premix, and stirring to obtain a polyurethane prepolymer; and mixing the compound foaming agent and the catalyst, adding the mixture into the polyurethane prepolymer, stirring, pouring into a mold paved with a skin, and heating and curing to obtain the high-connection-strength vehicle polyurethane foam. The polyurethane foam has the effect of improving the connection strength, the flame retardant property and the impact resistance of the polyurethane foam.

Description

Technical Field

[0001] The present application relates to the technical field of foam materials, and in particular to a polyurethane foam for automobiles with high connection strength and a preparation method thereof. Background Art

[0002] With the booming modern automotive industry, automotive performance, comfort, and safety have become key concerns for consumers. As a key component that directly impacts the driving experience, the selection and performance of automotive interior materials are crucial. Polyurethane foam, thanks to its excellent elasticity, sound absorption, and cushioning properties, has found widespread application in automotive interior applications such as seat padding and sound insulation.

[0003] However, with the continuous advancement of automotive technology and the increasing demand for automotive interior quality, automotive polyurethane foam faces a series of technical challenges that need to be addressed. In actual use, the stability of the connection between polyurethane foam and other automotive components has become a prominent issue.

[0004] Existing automotive polyurethane foams lack sufficient connection strength. This can lead to loosening and even detachment of the connections between the foam and other components during driving, especially when exposed to vibration, impact, and temperature fluctuations caused by complex road conditions. This not only affects the overall aesthetics and stability of the vehicle interior, but can also pose a potential safety hazard to occupants due to component displacement, and thus needs improvement. Summary of the Invention

[0005] In order to improve the connection strength of polyurethane foam, the present application provides a high-connection-strength automotive polyurethane foam and a preparation method thereof.

[0006] The present application provides a polyurethane foam for automobiles with high connection strength and a preparation method thereof, which adopts the following technical solutions: In a first aspect, the present application provides a polyurethane foam for automobiles with high connection strength, which adopts the following technical solutions: A polyurethane foam for automobiles with high connection strength, comprising the following components in parts by mass: 40-60 parts of polyether-modified bio-based polyol 30-50 parts of isocyanate 8-12 parts of chain extender 3-5 parts of compound foaming agent 0.5-1.5 parts of catalyst 1-3 parts surfactant 3-6 parts water.

[0007] Polyether-modified bio-based polyols provide abundant hydroxyl functional groups, laying the foundation for the formation of stable chemical bonds. Reacting with chain extenders, they can lengthen the molecular chains and enhance the cohesion of the foam. Isocyanates undergo polymerization with polyols and chain extenders to build a high-strength polyurethane network structure, giving the foam excellent mechanical properties. Chain extenders further increase molecular chain length and crosslinking, making the foam's internal structure more compact and improving bond strength. The compounded foaming agent produces uniform and stable bubbles, forming a regular and tightly connected pore structure within the foam, reducing stress concentration points and facilitating uniform force distribution, thereby improving overall bond strength. Catalysts accelerate the reaction process between the components, ensuring sufficient reaction and making the foam structure more stable. Surfactants reduce surface tension and promote uniform mixing of the components, facilitating the formation of a regular pore structure and a stable molecular network, thereby enhancing the internal connection of the foam and other materials. Water reacts with isocyanates to produce carbon dioxide, which not only assists in foaming but also participates in the construction of the polyurethane network, working synergistically with the compounded foaming agent to further strengthen the overall structure and bond strength of the foam.

[0008] Preferably, the raw materials for preparing the polyether-modified bio-based polyol include bio-based polyol and a polyether modifier.

[0009] Bio-based polyols are rich in active groups such as hydroxyl groups and can react chemically with polyether modifiers. The polyether-modified bio-based polyols generated by the reaction of the two, when polymerized with components such as isocyanates and chain extenders, can construct a denser and more regular three-dimensional network structure, enhance the intermolecular force, and thus improve the overall connection strength of the foam; the molecular chain flexibility and rigidity of polyether-modified bio-based polyols are well balanced. When impacted, their unique molecular structure can effectively disperse and absorb impact energy, preventing the foam from excessive deformation or rupture under impact, thereby significantly improving the impact resistance of the foam.

[0010] Preferably, the raw materials for preparing the polyether modifier include propylene oxide, allyl glycidyl ether and tannic acid.

[0011] The polyether structure generated by the reaction of propylene oxide and allyl glycidyl ether has good flexibility and reactivity, and can act as a bridge in the polyurethane network, enhance the chemical bonding between the components, and improve the connection strength. At the same time, the flexible polyether chain can effectively buffer energy when impacted and improve impact resistance; the unsaturated double bonds in allyl glycidyl ether can further participate in the cross-linking reaction, build a denser network, and strengthen the overall structure of the foam; tannic acid contains a large number of phenolic hydroxyl groups, which can not only react chemically with polyether to further optimize the molecular structure and improve the connection strength, but also form a dense carbonized layer at high temperature to play a flame retardant role; the rigid part in the tannic acid structure cooperates with the flexibility of the polyether, so that the foam has better impact resistance while ensuring flexibility. When impacted by external force, the rigid structure can prevent the foam from excessive deformation, while the flexible structure absorbs the impact energy, thereby jointly improving the comprehensive performance of the foam.

[0012] Preferably, the mass ratio of propylene oxide, allyl glycidyl ether and tannic acid is 1:0.75:(0.4-0.6).

[0013] The polyether modifier prepared according to the above mass ratio can effectively modify the bio-based polyol and improve the connection strength, flame retardancy and impact resistance of the polyurethane foam.

[0014] Preferably, the isocyanate comprises tetramethyl-m-xylylene diisocyanate.

[0015] Tetramethyl-m-xylylene diisocyanate contains two isocyanate groups, which can fully react with polyether-modified bio-based polyols, chain extenders, etc. to form a highly cross-linked three-dimensional network structure. Due to the steric effect of the methyl group in its molecule, the generated polyurethane molecular chains are arranged more regularly and tightly, enhancing the intermolecular forces, thereby greatly improving the connection strength of the foam; the benzene ring structure in tetramethyl-m-xylylene diisocyanate can undergo a carbonization reaction at high temperatures to form a dense carbon layer. This carbon layer can effectively isolate oxygen and heat transfer, inhibit the spread of flames, and improve the flame retardant properties of the foam; the regular and highly cross-linked network structure formed with the participation of tetramethyl-m-xylylene diisocyanate gives the foam good elasticity and toughness. When the foam is impacted, this network structure can evenly disperse the stress. The rigid structure of the benzene ring and the strong intermolecular forces make the foam less likely to break and deform, thereby effectively absorbing impact energy and improving the impact resistance of the foam.

[0016] Preferably, the raw materials for preparing the chain extender include dimethyl chlorophosphite and long-chain diamine.

[0017] Long-chain diamines provide multiple active amino groups. After reacting with dimethyl chlorophosphite, the resulting chain extender has a long-chain structure and unique phosphorus-nitrogen bonds. In polyurethane synthesis, chain extenders can react with polyether-modified bio-based polyols, isocyanates, and other materials to effectively increase the length and crosslink density of the molecular chains, resulting in a denser three-dimensional network structure in the foam and enhancing the connectivity between the various components within the foam, thereby improving the connection strength. Under high temperature conditions, phosphorus can promote the formation of a dense carbonized layer on the surface of the polyurethane foam. This carbonized layer effectively isolates oxygen and heat, thereby preventing the spread of flames and improving the foam's flame retardancy. The long-chain structure formed by long-chain diamines gives the chain extender a certain degree of flexibility, while the presence of phosphorus-nitrogen bonds enhances the rigidity of the molecule. When the foam is impacted, the long-chain structure can buffer energy through its own deformation, while the phosphorus-nitrogen bonds ensure structural stability, preventing excessive deformation or rupture of the foam under impact. The synergistic effect of these two factors enhances the foam's impact resistance.

[0018] Preferably, the chain extender is prepared by the following steps: Under the protection of neutral gas, dimethyl chlorophosphite and long-chain diamine are dispersed in toluene, stirred for reaction, and the solvent is removed by reduced pressure distillation to obtain a chain extender.

[0019] The chain extender prepared according to the above steps has good reaction performance and can effectively improve the connection strength, flame retardancy and impact resistance of polyurethane foam.

[0020] Preferably, the compound foaming agent includes pentane, azodicarbonamide and sodium bicarbonate.

[0021] Pentane has a low boiling point and is easily volatile, producing gas that forms uniform, tiny bubbles inside the foam. This provides a three-dimensional spatial framework for the growth of polyurethane molecular chains, making the molecular chains more evenly and fully cross-linked and enhancing the overall connection. The gases produced by the decomposition of azodicarbonamide and sodium bicarbonate further refine the pore structure, increase the interaction force between the pore walls, and improve the connection strength. Through the synergistic action of these three foaming agents, a uniform and fine pore structure is formed. When impacted, it can effectively absorb energy through the elastic deformation of the pore walls, preventing stress concentration, so that the foam can still maintain structural integrity under impact, thereby improving impact resistance.

[0022] Preferably, the mass ratio of pentane, azodicarbonamide and sodium bicarbonate is (1-2):1:0.25.

[0023] Compounding the foaming agent according to the above mass ratio can effectively improve the uniformity and fineness of the pores of the polyurethane foam.

[0024] In a second aspect, the present application provides a method for preparing polyurethane foam for automobiles with high connection strength, which adopts the following technical solution: A method for preparing polyurethane foam for automobiles with high connection strength comprises the following steps: A surfactant, a chain extender and water are added to a polyether-modified bio-based polyol and stirred to obtain a polyol premix; isocyanate is added to the polyol premix and stirred to obtain a polyurethane prepolymer; a compounded foaming agent and a catalyst are mixed and added to the polyurethane prepolymer, stirred and poured into a mold provided with a surface, and heated and cured to obtain automotive polyurethane foam with high connection strength.

[0025] The polyurethane foam prepared according to the above steps has a uniform, dense and interconnected pore structure, high connection strength, good flame retardant properties and impact resistance.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. Polyether-modified bio-based polyols provide abundant hydroxyl functional groups, laying the foundation for the formation of stable chemical bonds. Reaction with chain extenders can lengthen the molecular chain and enhance the cohesion of the foam. Isocyanate undergoes polymerization with the polyol and chain extender to build a high-strength polyurethane network structure, giving the foam good mechanical properties. The chain extender further increases the molecular chain length and the degree of cross-linking, making the foam's internal structure more compact and improving the bond strength. The compounded blowing agent produces uniform and stable bubbles, forming a regular and tightly connected pore structure within the foam, reducing stress concentration points and facilitating the uniform distribution of force, thereby improving the overall bond strength. The catalyst accelerates the reaction process between the components, ensuring sufficient reaction and making the foam structure more stable. The surfactant reduces surface tension and promotes uniform mixing of the components, facilitating the formation of a regular pore structure and a stable molecular network, thereby enhancing the bonding ability within the foam and with other materials. The reaction of water with isocyanate produces carbon dioxide, which not only assists in foaming but also participates in the construction of the polyurethane network. It works synergistically with the compounded blowing agent to further strengthen the overall structure and bond strength of the foam.

[0027] 2. The polyether structure generated by the reaction of propylene oxide and allyl glycidyl ether has good flexibility and reactivity, and can act as a bridge in the polyurethane network, enhance the chemical bonding between the components, and improve the connection strength. At the same time, the flexible polyether chain can effectively buffer energy when impacted and improve impact resistance; the unsaturated double bonds in allyl glycidyl ether can further participate in the cross-linking reaction, build a denser network, and strengthen the overall structure of the foam; tannic acid contains a large number of phenolic hydroxyl groups, which can not only react chemically with polyether to further optimize the molecular structure and improve the connection strength, but also form a dense carbonized layer at high temperature to play a flame retardant role; the rigid part in the tannic acid structure cooperates with the flexibility of the polyether, so that the foam has better impact resistance while ensuring flexibility. When impacted by external force, the rigid structure can prevent the foam from excessive deformation, while the flexible structure absorbs the impact energy, thereby jointly improving the comprehensive performance of the foam.

[0028] 3. Long-chain diamines provide multiple active amino groups. After reacting with dimethyl chlorophosphite, the resulting chain extender has a long-chain structure and unique phosphorus-nitrogen bonds. In polyurethane synthesis, chain extenders can react with polyether-modified bio-based polyols, isocyanates, and other materials to effectively increase the length and crosslink density of the molecular chains, resulting in a denser three-dimensional network structure in the foam and enhancing the connectivity between the various components within the foam, thereby improving the connection strength. Under high temperature conditions, phosphorus can promote the formation of a dense carbonized layer on the surface of the polyurethane foam. This carbonized layer effectively isolates oxygen and heat, thereby preventing the spread of flames and improving the flame retardant properties of the foam. The long-chain structure formed by long-chain diamines gives the chain extender a certain degree of flexibility, while the presence of phosphorus-nitrogen bonds enhances the rigidity of the molecule. When the foam is impacted, the long-chain structure can buffer energy through its own deformation, while the phosphorus-nitrogen bonds ensure structural stability, preventing excessive deformation or rupture of the foam under impact. The synergistic effect of these two factors improves the foam's impact resistance. DETAILED DESCRIPTION

[0029] The present application discloses a polyurethane foam for automobiles with high connection strength and a preparation method thereof. The raw materials used in the present application can be obtained from commercially available raw materials unless otherwise specified. The present application is further described in detail in conjunction with the examples below: Raw materials: Propylene oxide (CAS No.: 75-56-9), allyl glycidyl ether (CAS No.: 106-92-3), tannic acid (CAS No.: 1401-55-4), p-toluenesulfonic acid (CAS No.: 104-15-4), bio-based polyol model FHB-25 02, purchased from Zhangjiagang Feihang Technology Co., Ltd., dimethyl chlorophosphite (CAS No.: 2524-03-0), long-chain diamine is nonanediamine (CAS No.: 646-24-2), dibutyltin dilaurate (CAS No.: 77-58-7), surfactant model is SH-431 foaming agent, isocyanate is tetramethyl-m-xylylene diisocyanate (CAS No.: 2778-42-9), azodicarbonamide (CAS No.: 123-77-3), and the catalyst is dibutyltin dilaurate.

[0030] Example 1 Preparation of polyether-modified bio-based polyols Mix 23.26g of propylene oxide, 17.44g of allyl glycidyl ether and 0.2g of potassium hydroxide, stir at a speed of 500rpm, heat to 80℃ and react for 8h to obtain polyether; disperse 9.3g of tannic acid in 100mL of ethanol to obtain a tannic acid solution; add the tannic acid solution to the polyether, and add 0.5g of p-toluenesulfonic acid as a catalyst, heat to 80℃, stir at a speed of 500rpm and react for 8h. After cooling to below 30℃, remove the solvent by distillation under reduced pressure to obtain a crude product, wash the crude product three times with ether, and vacuum dry at 60℃ to obtain a polyether modifier.

[0031] The bio-based polyol was vacuum dried at 100°C for 2 hours to obtain anhydrous bio-based polyol; 30g of polyether modifier was dissolved in 120mL of toluene to obtain a modifier solution; the modifier solution was added to 60g of anhydrous bio-based polyol, 0.2g of dibutyltin dilaurate was added, and the mixture was stirred at 400rpm under heating in an oil bath at 130°C for 6h. After cooling to 30°C, the solvent was removed by distillation under reduced pressure, and the mixture was washed with anhydrous ethanol and vacuum dried at 60°C to constant weight to obtain polyether-modified bio-based polyol.

[0032] Preparation of chain extenders Under nitrogen protection, 12.1 g of dimethyl chlorophosphite and 17.9 g of long-chain diamine were dispersed in 200 mL of toluene, stirred at 200 rpm at 25° C. for 4 h, and the solvent was removed by distillation under reduced pressure to obtain a chain extender.

[0033] Preparation of high-strength automotive polyurethane foam To 40 g of polyether-modified bio-based polyol, 1 g of surfactant, 8 g of chain extender and 3 g of water were added, and the mixture was stirred at 150 rpm for 20 min to obtain a polyol premix; 30 g of isocyanate was added to the polyol premix and stirred at 400 rpm for 5 min to obtain a polyurethane prepolymer; 3 g of a compound foaming agent and 0.5 g of a catalyst were mixed and added to the polyurethane prepolymer, where the mass ratio of pentane, azodicarbonamide and sodium bicarbonate in the compound foaming agent was 1:1:0.25. The mixture was stirred at 500 rpm for 1.5 min, poured into a mold provided with a surface, and cured at 70°C for 3 h to obtain automotive polyurethane foam with high connection strength.

[0034] Example 2 Preparation of polyether-modified bio-based polyols Mix 21.28g of propylene oxide, 15.96g of allyl glycidyl ether and 0.2g of potassium hydroxide, stir at a speed of 500rpm, heat to 80℃ and react for 8h to obtain polyether; disperse 12.76g of tannic acid in 100mL of ethanol to obtain a tannic acid solution; add the tannic acid solution to the polyether, and add 0.5g of p-toluenesulfonic acid as a catalyst, heat to 80℃, stir at a speed of 500rpm and react for 8h. After cooling to below 30℃, remove the solvent by distillation under reduced pressure to obtain a crude product, wash the crude product three times with ether, and vacuum dry at 60℃ to obtain a polyether modifier.

[0035] The bio-based polyol was vacuum dried at 100°C for 2 hours to obtain anhydrous bio-based polyol; 30g of polyether modifier was dissolved in 120mL of toluene to obtain a modifier solution; the modifier solution was added to 60g of anhydrous bio-based polyol, 0.2g of dibutyltin dilaurate was added, and the mixture was stirred at 400rpm under heating in an oil bath at 130°C for 6h. After cooling to 30°C, the solvent was removed by distillation under reduced pressure, and the mixture was washed with anhydrous ethanol and vacuum dried at 60°C to constant weight to obtain polyether-modified bio-based polyol.

[0036] Preparation of chain extenders Under nitrogen protection, 12.1 g of dimethyl chlorophosphite and 17.9 g of long-chain diamine were dispersed in 200 mL of toluene, stirred at 200 rpm at 25° C. for 4 h, and the solvent was removed by distillation under reduced pressure to obtain a chain extender.

[0037] Preparation of high-strength automotive polyurethane foam To 60 g of polyether-modified bio-based polyol, 3 g of surfactant, 12 g of chain extender and 6 g of water were added, and the mixture was stirred at 150 rpm for 20 min to obtain a polyol premix; 50 g of isocyanate was added to the polyol premix and stirred at 400 rpm for 5 min to obtain a polyurethane prepolymer; 5 g of a compound foaming agent and 1.5 g of a catalyst were mixed and added to the polyurethane prepolymer, where the mass ratio of pentane, azodicarbonamide and sodium bicarbonate in the compound foaming agent was 2:1:0.25. The mixture was stirred at 500 rpm for 1.5 min, poured into a mold provided with a surface, and cured at 70°C for 3 h to obtain automotive polyurethane foam with high connection strength.

[0038] Example 3 Preparation of polyether-modified bio-based polyols Mix 22.22g of propylene oxide, 16.67g of allyl glycidyl ether and 0.2g of potassium hydroxide, stir at a speed of 500rpm, heat to 80℃ and react for 8h to obtain polyether; disperse 11.11g of tannic acid in 100mL of ethanol to obtain a tannic acid solution; add the tannic acid solution to the polyether, and add 0.5g of p-toluenesulfonic acid as a catalyst, heat to 80℃, stir at a speed of 500rpm and react for 8h. After cooling to below 30℃, remove the solvent by distillation under reduced pressure to obtain a crude product, wash the crude product three times with ether, and vacuum dry at 60℃ to obtain a polyether modifier.

[0039] The bio-based polyol was vacuum dried at 100°C for 2 hours to obtain anhydrous bio-based polyol; 30g of polyether modifier was dissolved in 120mL of toluene to obtain a modifier solution; the modifier solution was added to 60g of anhydrous bio-based polyol, 0.2g of dibutyltin dilaurate was added, and the mixture was stirred at 400rpm under heating in an oil bath at 130°C for 6h. After cooling to 30°C, the solvent was removed by distillation under reduced pressure, and the mixture was washed with anhydrous ethanol and vacuum dried at 60°C to constant weight to obtain polyether-modified bio-based polyol.

[0040] Preparation of chain extenders Under nitrogen protection, 12.1 g of dimethyl chlorophosphite and 17.9 g of long-chain diamine were dispersed in 200 mL of toluene, stirred at 200 rpm at 25° C. for 4 h, and the solvent was removed by distillation under reduced pressure to obtain a chain extender.

[0041] Preparation of high-strength automotive polyurethane foam To 50 g of polyether-modified bio-based polyol, 2 g of surfactant, 10 g of chain extender and 4.5 g of water were added, and the mixture was stirred at 150 rpm for 20 min to obtain a polyol premix; 40 g of isocyanate was added to the polyol premix, and the mixture was stirred at 400 rpm for 5 min to obtain a polyurethane prepolymer; 4 g of a compound foaming agent and 1 g of a catalyst were mixed and added to the polyurethane prepolymer, where the mass ratio of pentane, azodicarbonamide and sodium bicarbonate in the compound foaming agent was 1.5:1:0.25. The mixture was stirred at 500 rpm for 1.5 min, poured into a mold provided with a surface, and cured at 70°C for 3 h to obtain automotive polyurethane foam with high connection strength.

[0042] Example 4 Example 4 is based on Example 3. The only difference between Example 4 and Example 3 is that in Example 4, the amount of propylene oxide used is 25.64 g, the amount of allyl glycidyl ether used is 19.23 g, and the amount of tannic acid used is 5.13 g.

[0043] Example 5 Example 5 is based on Example 3. The only difference between Example 5 and Example 3 is that in Example 5, the amount of propylene oxide used is 19.61 g, the amount of allyl glycidyl ether used is 14.71 g, and the amount of tannic acid used is 15.68 g.

[0044] Example 6 Example 6 is based on Example 3. The only difference between Example 6 and Example 3 is that allyl glycidyl ether is not added when preparing the polyether modifier in Example 6.

[0045] Example 7 Example 7 is based on Example 3. The only difference between Example 7 and Example 3 is that the chain extender is replaced by a long-chain diamine in Example 7.

[0046] Example 8 Example 8 is based on Example 3. The only difference between Example 8 and Example 3 is that the mass ratio of pentane, azodicarbonamide and sodium bicarbonate in Example 8 is 0.5:1:0.25.

[0047] Example 9 Example 9 is based on Example 3. The only difference between Example 9 and Example 3 is that the mass ratio of pentane, azodicarbonamide and sodium bicarbonate in Example 9 is 3:1:0.25.

[0048] Example 10 Example 10 is based on Example 3. The only difference between Example 10 and Example 3 is that sodium bicarbonate is not added to the compound foaming agent in Example 10.

[0049] Example 11 Example 11 is based on Example 3. The only difference between Example 11 and Example 3 is that pentane is not added to the compound foaming agent in Example 11.

[0050] Comparative Example 1 Comparative Example 1 is based on Example 3. The only difference between Comparative Example 1 and Example 3 is that in Comparative Example 1, the polyether-modified bio-based polyol is replaced by a bio-based polyol.

[0051] Performance testing (1) GB / T2792-2014 Test method for peel strength of adhesive tape was selected as the standard. The 180° peel strength of polyurethane foam was tested using a desktop tensile testing machine. Three samples were prepared for each test specimen. The average value was taken after measurement and the results were recorded in Table 1.

[0052] (2) GB / T 2406.2-2009 Plastics - Determination of Combustion Behavior by Oxygen Index Method - Part 2: Room Temperature Test was selected as the standard. The limiting oxygen index of the sample was tested using an oxygen index tester. Three samples were prepared for each sample. The average value was taken after measurement and the results were recorded in Table 1.

[0053] (3) Select "GB / T 1843-2008 Determination of Izod Impact Strength of Plastics" as the standard to test the impact strength of the specimens. Prepare three samples for each specimen, take the average value after measurement, and record the results in Table 1.

[0054] Table 1 Test results of polyurethane foam connection strength, flame retardancy and impact resistance Test results Peel force (N / 25mm) Limiting oxygen index (%) <![CDATA[Impact strength (kJ / m 2 )]]> Example 1 20.85 29.8 8.2 Example 2 20.93 30.1 8.3 Example 3 21.02 30.5 8.5 Example 4 19.36 28.9 7.5 Example 5 17.25 27.3 7.1 Example 6 17.09 27.1 7.0 Example 7 18.69 26.3 7.3 Example 8 19.64 29.1 7.6 Example 9 19.32 28.5 7.2 Example 10 18.43 28.1 6.8 Example 11 18.12 27.8 6.5 Comparative Example 1 16.24 26.2 6.1 As shown in Table 1, the peeling force of Examples 1-3 is greater than 20.85N / 25mm, the limiting oxygen index is greater than 29.8%, and the impact strength is greater than 8.2kJ / m 2 , which shows that the polyurethane foam prepared in this application has high connection strength, good flame retardant properties and impact resistance.

[0055] As can be seen from Table 1, the only difference between Examples 4, 5, and 6 and Example 3 is that in Example 4, the mass ratio of propylene oxide, allyl glycidyl ether, and tannic acid is 1:0.75:0.2, and in Example 5, the mass ratio of propylene oxide, allyl glycidyl ether, and tannic acid is 1:0.75:0.8. In Example 6, no allyl glycidyl ether is added when preparing the polyether modifier. Compared with Example 3, the connection strength, flame retardancy, and impact resistance of Examples 4, 5, and 6 are all reduced. This is because the ratio of the components in the polyether modifier is changed. Too much tannic acid will increase the rigidity of the molecular chain and cause excessive cross-linking. Too little tannic acid will only improve the modification effect to a limited extent. Without adding allyl glycidyl ether, there is a lack of active double bonds, and the flexibility and reactivity are reduced, thereby reducing the performance of the polyurethane foam.

[0056] As can be seen from Table 1, the only difference between Example 7 and Example 3 is that the chain extender is replaced by a long-chain diamine in Example 7. Compared with Example 3, Example 7 has decreased connection strength, flame retardancy and impact resistance. This is because the lack of the introduction of phosphite, the lack of the flame retardant effect of the phosphorus-nitrogen bond and the phosphorus element, the structural rigidity is reduced, and the flame retardancy deteriorates.

[0057] As can be seen from Table 1, the only difference between Examples 8, 9, 10, and 11 and Example 3 is that in Example 8, the mass ratio of pentane, azodicarbonamide, and sodium bicarbonate is 0.5:1:0.25, in Example 9, the mass ratio of pentane, azodicarbonamide, and sodium bicarbonate is 3:1:0.25, in Example 10, no sodium bicarbonate is added to the compound foaming agent, and in Example 11, no pentane is added to the compound foaming agent. Compared with Example 3, Examples 8, 9, 10, and 11 have decreased connection strength, flame retardant properties, and impact resistance. This is because changing the ratio and composition of the compound foaming agent affects the pore structure of the foam, and the uniformity and fineness of the foam are reduced, thereby reducing the connection strength, flame retardant properties, and impact resistance.

[0058] As can be seen from Table 1, the only difference between Comparative Example 1 and Example 3 is that the polyether-modified bio-based polyol is replaced by a bio-based polyol in Comparative Example 1. Compared with Example 3, the connection strength, flame retardancy, and impact resistance of Comparative Example 1 are reduced. This is because the polyether-modified bio-based polyol is replaced by a bio-based polyol, and the modification treatment of the polyether modifier is lacking, the cross-linking degree of the molecular chain is reduced, the structural stability is reduced, and the flame retardancy and impact resistance are also reduced.

[0059] This specific embodiment is merely an explanation of the present application and does not limit the present application. Based on the above description, relevant personnel can make various changes and modifications without departing from the technical scope of the present application. The technical scope of the present application is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A polyurethane foam for automobile with high connection strength, characterized in that: The composition includes the following components in parts by weight: 40-60 parts of polyether modified bio-based polyol Isocyanate 30-50 parts Chain extender 8-12 parts 3-5 parts of compound foaming agent Catalyst 0.5-1.5 parts Surfactant 1-3 parts 3-6 parts water.

2. The polyurethane foam for automobiles with high connection strength according to claim 1, characterized in that: The raw materials for preparing the polyether-modified bio-based polyol include bio-based polyol and a polyether modifier.

3. The polyurethane foam for automobiles with high connection strength according to claim 2, characterized in that: The raw materials for preparing the polyether modifier include propylene oxide, allyl glycidyl ether and tannic acid.

4. The polyurethane foam with high connection strength for vehicles according to claim 3, characterized in that: The mass ratio of propylene oxide, allyl glycidyl ether and tannic acid is 1:0.75:(0.4-0.6).

5. The polyurethane foam with high connection strength for vehicles according to claim 1, characterized in that: The isocyanate includes tetramethyl-meta-xylylene diisocyanate.

6. The polyurethane foam with high connection strength for vehicles according to claim 1, characterized in that: The raw materials for preparing the chain extender include dimethyl chlorophosphite and long-chain diamine.

7. The polyurethane foam with high connection strength for vehicles according to claim 6, characterized in that: The chain extender is prepared by the following steps: Under the protection of neutral gas, dimethyl chlorophosphite and long-chain diamine are dispersed in toluene, stirred for reaction, and the solvent is removed by reduced pressure distillation to obtain a chain extender.

8. The polyurethane foam with high connection strength for vehicles according to claim 1, characterized in that: The composite foaming agent comprises pentane, azodicarbonamide and sodium bicarbonate.

9. The polyurethane foam with high connection strength for vehicles according to claim 8, characterized in that: The mass ratio of pentane, azodicarbonamide and sodium bicarbonate is (1-2):1:0.

25.

10. A method for preparing a polyurethane foam for a vehicle with high connection strength as claimed in any one of claims 1 to 9, characterized in that: The following steps are involved: Add surfactant, chain extender and water to polyether modified bio-based polyol, stir to obtain polyol premix; add isocyanate to the polyol premix, stir to obtain polyurethane prepolymer; mix the compound blowing agent and catalyst and add to the polyurethane prepolymer, stir and pour into a mold with a surface, heat and cure to obtain automotive polyurethane foam with high connection strength.