A polyurethane foam and a method for its production and use

Abstract

This invention relates to the field of polymer materials technology, disclosing a polyurethane foam, its preparation method, and its applications. The polyurethane foam is obtained by reacting component A and component B. Component A includes a polyether polyol, a catalyst, and a blowing agent. The polyether polyol includes polyether polyol A1, which is polymerized using propylene oxide and ethylene oxide as monomers and terminated with ethylene oxide. The mass fraction of ethylene oxide in the polymer monomers is 20wt%~50wt%. Component B is an isocyanate component. This invention uses a polyether polyol with a specific structure to react with isocyanate, which can enhance the reactivity of the system and accelerate the maturation process, resulting in a more uniform and stable molding structure. While maintaining low density, the resulting material still possesses good mechanical properties and sound absorption capabilities, and can be widely used in acoustic components such as automotive sound insulation pads, carpets, and front panels, meeting the needs for lightweighting, noise reduction, and improved comfort.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a polyurethane foam, its preparation method, and its application. Background Technology

[0002] Polyurethane foam, a commonly used functional polymer material, is widely used in transportation equipment such as automobiles, high-speed trains, and aircraft. In automobile manufacturing, it is often used in acoustic components such as carpets, front panels, coat racks, and spare tire pads. It not only serves a decorative purpose but also performs functions such as sound absorption, noise reduction, and vibration damping, playing an important role in improving the overall comfort of the vehicle.

[0003] Currently, most automotive acoustic components are manufactured using modified diphenylmethane diisocyanate (MDI) systems. This system offers faster foaming and curing speeds and shorter demolding cycles, but its high raw material costs make it difficult to meet the automotive industry's increasing demands for lightweighting, cost optimization, and high-speed production. In contrast, modified toluene diisocyanate (TDI) systems offer advantages such as lower density and lower cost, making them more suitable for the manufacture of large-scale acoustic components; however, their curing speed is generally slower, making it difficult to meet the rapid molding requirements of components such as sound insulation pads.

[0004] Existing processes struggle to simultaneously achieve rapid curing and improved material properties within the toluene diisocyanate (TDI) system. This results in difficulties in obtaining the structural strength and sound absorption performance required for acoustic components such as sound insulation pads while maintaining low density and cost advantages. Therefore, the industry urgently needs a technical solution that can improve the reactivity of the TDI system, shorten curing time, and ensure the stability of the molded structure, in order to meet the demands of acoustic components for high-efficiency production and balanced overall performance. Summary of the Invention

[0005] This invention provides a polyurethane foam, its preparation method, and its application, to solve the problems in the prior art where polyurethane foam has a slow curing speed, significant fluctuations in material properties, and difficulty in simultaneously achieving good sound absorption performance and structural strength under low cost and low density conditions.

[0006] In a first aspect, the present invention provides a polyurethane foam obtained by reacting component A and component B;

[0007] Component A includes a polyether polyol, a catalyst, and a blowing agent. The polyether polyol comprises polyether polyol A1, which is formed by polymerizing propylene oxide and ethylene oxide as monomers and end-capping with ethylene oxide. The mass fraction of ethylene oxide in the monomers is 20wt%~50wt%; for example, the mass fraction of ethylene oxide in the monomers is 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, and 50wt%.

[0008] Component B is an isocyanate component.

[0009] This invention introduces a polyether polyol A1, composed of propylene oxide and ethylene oxide as monomers and capped with ethylene oxide, into component A. This results in a polyether polyol exhibiting higher end-group activity and stronger hydrophilicity compared to conventional polyether systems. On one hand, the ethylene oxide capping structure increases the reaction rate of the hydroxyl end groups, promoting crosslinking with isocyanate component B, thereby effectively shortening the curing time of the polyurethane system and significantly improving molding efficiency. On the other hand, an appropriate range of ethylene oxide content improves the nucleation process, making microbubbles easier to form and more uniformly distributed, ultimately resulting in a material with a fine and uniform pore structure.

[0010] Meanwhile, by selecting isocyanate component B and matching it with the aforementioned highly active polyether system, this invention achieves good crosslinking and structural stability while maintaining a low density. This results in a more balanced material in terms of tensile strength, tear resistance, and compressive strength, combining lightweight and durability. Furthermore, the fine and stable cell structure also enhances sound absorption performance, making the polyurethane foam of this invention more suitable for applications such as automotive sound insulation pads.

[0011] In one optional embodiment, the polyether polyol further includes polyether polyol A2, which is formed by using propylene oxide and ethylene oxide as polymerizing monomers and end-capping with ethylene oxide, wherein the mass fraction of ethylene oxide in the polymerizing monomers is 12wt%~18wt%; for example, the mass fraction of ethylene oxide in the polymerizing monomers is 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, or 18wt%.

[0012] In an optional embodiment, the polyether polyol further includes polyether polyol A3, which is formed by using propylene oxide and ethylene oxide as polymerizing monomers, grafting with styrene-acrylonitrile copolymer, and end-capping with ethylene oxide. The mass fraction of ethylene oxide in the polymerizing monomers is 8wt%~12wt%; for example, the mass fraction of ethylene oxide in the polymerizing monomers is 8wt%, 9wt%, 10wt%, 11wt%, or 12wt%.

[0013] By further introducing polyether polyols A2 and A3 into component A, fine-tuning of the foam structure and properties can be achieved while maintaining the system's reactivity. An appropriate amount of ethylene oxide in polyether polyol A2 enhances the hydrophilicity of the end groups, facilitating the reaction, shortening the curing time, and improving cell uniformity. Polyether polyol A3, due to its styrene-acrylonitrile copolymer graft structure, improves the material's mechanical strength, tear resistance, and structural stability, especially maintaining good deformation recovery under low-density conditions. The synergistic effect of these two components results in a better balance between rapid curing, mechanical properties, and sound absorption performance in the final material.

[0014] In one optional embodiment, the polyether polyol A1 has an average functionality of 3-4 and a hydroxyl value of 24-42 mgKOH / g. For example, the average functionality can be 3.0, 3.2, 3.5, 3.8, or 4.0, and the hydroxyl value can be 24 mgKOH / g, 28 mgKOH / g, 32 mgKOH / g, 36 mgKOH / g, 40 mgKOH / g, or 42 mgKOH / g.

[0015] In one optional embodiment, the polyether polyol A2 has an average functionality of 3-5 and a hydroxyl value of 24-42 mgKOH / g. For example, the average functionality can be 3.0, 3.5, 4.0, 4.5, or 5.0, and the hydroxyl value can be 24 mgKOH / g, 28 mgKOH / g, 32 mgKOH / g, 36 mgKOH / g, 40 mgKOH / g, or 42 mgKOH / g.

[0016] In one optional embodiment, the polyether polyol A3 has an average functionality of 3-5 and a hydroxyl value of 20-30 mgKOH / g. For example, the average functionality can be 3.0, 3.5, 4.0, 4.5, or 5.0, and the hydroxyl value can be 20 mgKOH / g, 22 mgKOH / g, 24 mgKOH / g, 26 mgKOH / g, 28 mgKOH / g, or 30 mgKOH / g.

[0017] In one optional embodiment, by weight, component A comprises 10-50 parts of polyether polyol A1, 30-60 parts of polyether polyol A2, 20-50 parts of polyether polyol A3, 1.3-1.7 parts of catalyst, and 3-6 parts of blowing agent. For example, the polyether polyol A1 can be 10 parts, 30 parts, or 50 parts; the polyether polyol A2 can be 30 parts, 45 parts, or 60 parts; the polyether polyol A3 can be 20 parts, 35 parts, or 50 parts; the catalyst can be 1.3 parts, 1.5 parts, or 1.7 parts; and the blowing agent can be 3 parts, 4.5 parts, or 6 parts.

[0018] In one optional embodiment, the catalyst comprises one or more of the following: bis(2-dimethylaminoethyl) ether (CAS No.: 3033-62-3), N,N,N'-trimethyl-N'-hydroxyethyl bisaminoethyl ether, dimethylaminopropylamine, N,N'-dimethylethanolamine, bis(3-dimethylaminopropyl)aminoisopropanol, tetramethyldipropylenetriamine, pentamethyldiethylenetriamine, triethylenediamine, and 3,3'-iminobis(N,N-dimethylpropylamine);

[0019] In one alternative embodiment, the foaming agent includes one or more of water, carbon dioxide, dichlorofluoroethane, butane, n-pentane, cyclopentane, and isopentane.

[0020] In one optional embodiment, component A further includes other adjuvants, including one or more of diethanolamine, triethanolamine, ethylene glycol, diethylene glycol, glycerol, dipropylene glycol, 1,4-butanediol, trimethylolpropane, and pentaerythritol.

[0021] This invention, by further adding additives such as diethanolamine, triethanolamine, ethylene glycol, diethylene glycol, glycerol, dipropylene glycol, 1,4-butanediol, trimethylolpropane, or pentaerythritol to component A, can regulate the hydrophilicity, reaction rate, and network crosslinking degree of the system during the foaming process, making the foam structure more stable. At the same time, these additives can improve the uniformity of cell structure, enhance the mechanical strength and compression recovery performance of the material, and further improve molding consistency, which is beneficial to obtaining a polyurethane foam material with more stable overall performance.

[0022] In one optional embodiment, the initiator of the polyether polyol is selected from small molecule alcohols with a functionality of 3 to 6;

[0023] Preferably, the initiator includes one or more of glycerol, trimethylolpropane, pentaerythritol, and sorbitol.

[0024] In one optional embodiment, the mass ratio of component A to component B is 100:30 to 70; for example, the mass ratio can be 100:30, 100:42, 100:50, 100:65, 100:60 or 100:70.

[0025] Preferably, the mass ratio of component A to component B is 100:42~65.

[0026] Secondly, the present invention provides a method for preparing polyurethane foam according to any of the above technical solutions, comprising: mixing component A and component B, injecting the mixture into a mold at a temperature of 50°C to 80°C and foaming for 60s to 100s to obtain the polyurethane foam; for example, the mold temperature can be 50°C, 60°C, 70°C or 80°C, and the foaming time can be 60s, 70s, 80s, 85s, 90s or 100s.

[0027] Preferably, component A and component B are mixed at a temperature of 20°C to 40°C; for example, the mixing temperature of component A and component B can be 20°C, 25°C, 30°C, 35°C or 40°C.

[0028] Preferably, the foaming time is 70s to 85s. For example, the foaming time can be 70s, 75s, 80s, or 85s.

[0029] By controlling the above process conditions, component A and component B can fully react at a suitable temperature, ensuring that the materials possess good flowability and reactivity. This facilitates rapid and stable foaming and molding in the mold. Further optimization of the mixing temperature and foaming time helps improve curing efficiency, enhance internal structural uniformity, and increase molding stability. The resulting polyurethane material maintains low density while possessing excellent comprehensive mechanical and acoustic properties, better meeting the requirements of acoustic components for efficient molding and stable quality.

[0030] Thirdly, the present invention provides an application of polyurethane foam as described in any of the above technical solutions in automotive parts.

[0031] The technical solution of this invention has the following advantages:

[0032] This invention utilizes propylene oxide and ethylene oxide as monomers, with a specific structure of polyether polyols capped with ethylene oxide as the core component, to react with isocyanate components. This significantly enhances the reactivity of the system, making it easier for the material to form a uniform and stable three-dimensional structure during molding. This not only effectively shortens curing time and improves production efficiency, but also maintains good mechanical properties and sound absorption performance under low-density conditions. The overall performance is superior to existing conventional systems, making it more suitable for the practical needs of lightweight and high-speed production of automotive acoustic components.

[0033] The preparation method of this invention enables component A and component B to react fully and successfully complete foaming under suitable temperature conditions, resulting in more uniform reaction and a more stable structure formation process. This facilitates the production of polyurethane materials with rapid curing speed, uniform cell structure, and stable physical properties. Furthermore, this method exhibits good process adaptability, meeting the comprehensive requirements of acoustic components for efficient production and high-quality molding.

[0034] The polyurethane foam obtained by this invention can be applied to acoustic structural components such as automotive carpets, front bulkheads, sound insulation pads, and spare tire pads. It still has good mechanical performance and sound absorption capacity under low density conditions, and can meet the comprehensive requirements of vehicle lightweighting, noise reduction and comfort improvement. Attached Figure Description

[0035] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 This is a graph showing the change in sound absorption coefficient of the embodiments and comparative examples of the present invention. Detailed Implementation

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] The raw materials involved in the embodiments and comparative examples of this invention are as follows:

[0039] Polyether polyol A 1-1Using glycerol as an initiator, propylene oxide and ethylene oxide were used as monomers for addition polymerization, followed by ethylene oxide end-capping treatment. This resulted in polyether segments containing both internal propylene oxide and internal ethylene oxide units, with ethylene oxide-terminated ends. The ethylene oxide mass fraction in the monomers was 28%, yielding polyether polyol A. 1-1 Of the hydroxyl end groups, primary hydroxyl groups account for 85% of the total number of hydroxyl groups, the hydroxyl value is 32 mgKOH / g, and the average functionality is 3.

[0040] Polyether polyol A 1-2 Using glycerol and sorbitol as initiators, and propylene oxide and ethylene oxide as monomers, addition polymerization was carried out, with ethylene oxide end-capping treatment to ensure that the polyether segments simultaneously contain internal propylene oxide units and internal ethylene oxide units, with ethylene oxide-terminated structures at the ends. The mass fraction of ethylene oxide in the monomers was 21%, resulting in polyether polyol A. 1-2 Of the hydroxyl end groups, primary hydroxyl groups account for 83% of the total number of hydroxyl groups, the hydroxyl value is 33 mg KOH / g, and the average functionality is 3.

[0041] Polyether polyol A 1-3 Using glycerol as an initiator, propylene oxide and ethylene oxide were used as monomers for addition polymerization, followed by ethylene oxide end-capping treatment. This resulted in polyether segments containing both internal propylene oxide and internal ethylene oxide units, with ethylene oxide-terminated ends. The ethylene oxide mass fraction in the monomers was 20%, yielding polyether polyol A. 1-3 In the hydroxyl terminal group, primary hydroxyl groups account for 80% of the total number of hydroxyl groups, the hydroxyl value is 24 mgKOH / g, and the average functionality is 3.

[0042] Polyether polyol A 1-4 Using glycerol and sorbitol as initiators, and propylene oxide and ethylene oxide as monomers, addition polymerization was carried out, with ethylene oxide end-capping treatment to ensure that the polyether segments simultaneously contain internal propylene oxide units and internal ethylene oxide units, with ethylene oxide-terminated structures at the ends. The mass fraction of ethylene oxide in the monomers was 50%, resulting in polyether polyol A. 1-4 Of the hydroxyl end groups, primary hydroxyl groups account for 81% of the total number of hydroxyl groups, the hydroxyl value is 42 mg KOH / g, and the average functionality is 4.

[0043] Polyether polyol A 2-1 Addition polymerization was carried out using glycerol as the initiator and propylene oxide and ethylene oxide as the monomers, followed by end-capping treatment with ethylene oxide. The mass fraction of ethylene oxide in the monomers was 15%. The resulting polyether polyol A 2-1 Of the hydroxyl end groups, primary hydroxyl groups account for 82% of the total number of hydroxyl groups, the hydroxyl value is 33 mgKOH / g, and the average functionality is 3.

[0044] Polyether polyol A 2-2 The polymerization was initiated with glycerol and carried out by addition polymerization using propylene oxide and ethylene oxide as monomers, followed by end-capping with ethylene oxide. The mass fraction of ethylene oxide in the monomers was 16%, resulting in polyether polyol A. 2-2 Of the hydroxyl end groups, primary hydroxyl groups account for 85% of the total number of hydroxyl groups, the hydroxyl value is 28 mgKOH / g, and the average functionality is 3.

[0045] Polyether polyol A 2-3 The polymerization was initiated with glycerol and carried out by addition polymerization using propylene oxide and ethylene oxide as monomers, followed by end-capping with ethylene oxide. The mass fraction of ethylene oxide in the monomers was 12%, resulting in polyether polyol A. 2-3 In the hydroxyl terminal group, primary hydroxyl groups account for 80% of the total number of hydroxyl groups, the hydroxyl value is 24 mgKOH / g, and the average functionality is 3.

[0046] Polyether polyol A 2-4 The polymerization was initiated with glycerol and carried out by addition polymerization using propylene oxide and ethylene oxide as monomers, followed by end-capping with ethylene oxide. The mass fraction of ethylene oxide in the monomers was 18%, resulting in polyether polyol A. 2-4 Of the hydroxyl end groups, primary hydroxyl groups account for 82% of the total number of hydroxyl groups, the hydroxyl value is 42 mg KOH / g, and the average functionality is 4.2.

[0047] Polymer polyol A 3-1 Using glycerol as an initiator and propylene oxide and ethylene oxide as monomers, addition polymerization was carried out. During polymerization, a styrene-acrylonitrile copolymer was introduced to form a graft structure, and the polymer was end-capped with ethylene oxide, resulting in polyether segments containing both internal propylene oxide and internal ethylene oxide units, with ethylene oxide-terminated ends. The mass fraction of ethylene oxide in the monomers was 11%, and the resulting polymer polyol A... 3-1 The hydroxyl value is 24 mgKOH / g, the average functionality is 3, and the grafted solids content is 30%; where the grafted solids content refers to the mass fraction of the grafted phase formed by the styrene-acrylonitrile copolymer in the polymer polyol.

[0048] Polymer polyol A 3-2 Using glycerol as an initiator and propylene oxide and ethylene oxide as monomers, addition polymerization was carried out. During polymerization, a styrene-acrylonitrile copolymer was introduced to form a graft structure, and ethylene oxide was used for end-capping treatment, resulting in polyether segments containing both internal propylene oxide and internal ethylene oxide units, with ethylene oxide-terminated ends. The mass fraction of ethylene oxide in the monomers was 10%, and the resulting polymer polyol A... 3-2The hydroxyl value is 22 mg KOH / g, the average functionality is 3, and the grafted solids content is 40%.

[0049] Polymer polyol A 3-3 Using glycerol as the initiator and propylene oxide and ethylene oxide as monomers, addition polymerization was carried out. During polymerization, a styrene-acrylonitrile copolymer was introduced to form a graft structure, and the polymer was end-capped with ethylene oxide, resulting in polyether segments containing both internal propylene oxide and internal ethylene oxide units, with ethylene oxide-terminated ends. The ethylene oxide mass fraction of the monomers was 8%, and the resulting polymer polyol A... 3-3 The hydroxyl value is 20 mg KOH / g, the average functionality is 3, and the grafted solids content is 42%.

[0050] Polymer polyol A 3-4 Using glycerol as an initiator and propylene oxide and ethylene oxide as monomers, addition polymerization was carried out. During polymerization, a styrene-acrylonitrile copolymer was introduced to form a graft structure, and ethylene oxide was used for end-capping treatment, resulting in polyether segments containing both internal propylene oxide and internal ethylene oxide units, with ethylene oxide-terminated ends. The mass fraction of ethylene oxide in the monomers was 12%, and the resulting polymer polyol A... 3-4 The hydroxyl value is 30 mg KOH / g, the average functionality is 3, and the grafted solids content is 15%.

[0051] Catalyst 1: bis(3-dimethylaminopropyl)aminoisopropanol;

[0052] Catalyst 2,3,3'-iminobis(N,N-dimethylpropylamine), CAS No. 6711-48-4;

[0053] Catalyst 3, N,N,N'-trimethyl-N'-hydroxyethyl diaminoethyl ether, CAS No. 83016-70-0;

[0054] Surfactant 1, Evonik B8734LF2;

[0055] Surfactant 2, Dow Chemical HR-8071;

[0056] A mixture of isocyanate B1, polymethylene polyphenyl polyisocyanate (CAS No. 9016-87-9) and toluene diisocyanate (including isomers), with an NCO content of 39.5%, commercially available, Wanhua WANNATE 7050;

[0057] A mixture of isocyanate B2, polymethylene polyphenyl polyisocyanate and toluene diisocyanate (including isomers), with an NCO content of 45.0%, commercially available, Wanhua WANNATE 7080;

[0058] Isocyanate B3, a mixture of polymethylene polyphenyl polyisocyanate, diphenylmethane-4,4'-diisocyanate and toluene diisocyanate (including isomers), with an NCO content of 36.8%, commercially available, WANNATE 7024.

[0059] Isocyanate B4 is a mixture of polymethylene polyphenyl polyisocyanate, diphenylmethane-4,4'-diisocyanate, polyol-modified isocyanate prepolymer and toluene diisocyanate (including isomers), with an NCO content of 36.3%, commercially available, Wanhua WANNATE 7065YF.

[0060] The detection methods involved in the embodiments and comparative examples of this invention are as follows:

[0061] The density test of polyurethane foam is conducted according to ISO 845-2006.

[0062] Tensile strength test and elongation at break test: The test standard adopted is ISO 1798-2008;

[0063] Tear strength test: The test standard used is ISO 8067-2018;

[0064] 40% compressive strength test: The standard used is ISO 3386-1:2025;

[0065] 50% compression set test: The standard used is ISO 1865-2018.

[0066] Sound absorption test: The test standard adopted is GB / T 18696.2. The test specimens are disc-shaped specimens with diameters of 99mm and 29mm and a thickness of (20±2)mm. The sound absorption requirements in "Q-JLYJ7110657C-2024 Foamed Polyurethane (PU) Material for Sound Insulation Pads of Passenger Cars" are the target.

[0067] For any experimental steps or conditions not specified in the following examples and comparative examples, the procedures and conditions described in the literature in this field can be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0068] The present invention will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed by the present invention.

[0069] Example

[0070] This embodiment provides polyurethane foam and its preparation method, wherein Examples 1 to 9 are prepared according to the formulation and process in Table 1, as detailed below:

[0071] The raw materials corresponding to component A are mixed uniformly at 25°C according to the mass proportions shown in Table 1. This mixture is then thoroughly mixed with component B, measured at the same temperature (25°C). After mixing, the resulting material is injected into a mold at 65°C for reaction and foaming. The formulations and curing times for each embodiment are shown in Table 1 below, where curing time refers to the foaming reaction time of the material in the mold.

[0072] After foaming is complete, open the mold and remove the foam to obtain polyurethane foam.

[0073] Table 1: Raw material ratios for Examples 1-9:

[0074]

[0075] (In the table, " / " indicates that the substance is not added.)

[0076] Comparative Example 1

[0077] The difference between this comparative example and Example 1 is that polyol A1 is not added to component A, resulting in an increased aging time; specifically, this comparative example uses 10 parts by weight of polyol A1 from Example 1. 1-1 and 50 parts by weight of polyol A 2-1 Replace with 60 parts by weight of polyol A 2-1 The curing time is 100 seconds.

[0078] Comparative Example 2

[0079] The difference between this comparative example and Example 1 is that component A in Example 1 is replaced with an equal mass of "combined polyether WANEFLEX". ® "532N", curing time is 90s, and other formulas and process parameters are consistent with those in Example 1.

[0080] Comparative Example 3

[0081] The difference between this comparative example and Example 1 is that component A in Example 1 is replaced with an equal mass of "combined polyether WANEFLEX". ® The curing time was 110 seconds, and the other formulas and process parameters remained the same as in Example 1.

[0082] Test Example 1

[0083] This test example tested the density, tensile strength, elongation at break, tear strength, 40% compressive strength, and 50% compression set of the foam materials obtained in Examples 1 to 9 and Comparative Examples 1 to 3. The test results are listed in Table 2.

[0084] Table 2: Physical and mechanical properties of foam materials from the embodiments and comparative examples of the present invention

[0085]

[0086] As can be seen from Table 2 above, Examples 1 to 9 of the present invention were all completed in a shorter curing time, which is significantly better than the curing efficiency of the comparative examples. Furthermore, even under rapid curing conditions, the foam obtained by the present invention still maintains good mechanical properties, including high tensile and tear strength, reasonable compression performance and small compression set, with balanced and stable overall performance.

[0087] Combination Figure 1 The trend of sound absorption coefficient shown demonstrates that the foam of this invention exhibits good sound absorption performance within the target frequency band, with the overall sound absorption curve exceeding the target requirements of "Q-JLYJ7110657C-2024 Foamed Polyurethane (PU) Material for Passenger Vehicle Sound Insulation Pads". This indicates that the present invention achieves both rapid curing and low-density molding while maintaining excellent mechanical properties and sound absorption performance. Its comprehensive performance is significantly superior to existing conventional systems, making it more suitable for meeting the dual demands of high-speed production and low cost for automotive sound insulation pads.

[0088] Comparing Example 1 and Comparative Example 1, it can be seen that component A in Comparative Example 1 did not contain polyether polyol A1, but was composed of polyether polyol A2 and polymer polyol A3. In the absence of polyether polyol A1, the reaction end group activity and hydrophilicity of the system are reduced, resulting in a significant slowdown in the foaming and curing process and a significantly prolonged curing time. Simultaneously, the structure formation process of the material obtained in Comparative Example 1 is less stable than that in Example 1, the uniformity and resilience of the three-dimensional network are affected, and its mechanical properties and compressive deformation are also weakened to varying degrees.

[0089] Therefore, it is evident that the introduction of polyether polyol A1 in this invention can effectively enhance the system reaction rate, improve nucleation conditions and structure formation quality, enabling the material to obtain a more uniform and stable internal structure within a shorter curing time. The comparative results of Comparative Example 1 further illustrate that the lack of polyether polyol A1 restricts the system reaction and structure building process, thereby affecting molding efficiency and final performance. This verifies the rationality of the polyol combination design in this invention.

[0090] Comparing the embodiments of the present invention with Comparative Examples 2 and 3, it can be seen that after replacing component A entirely with commercially available polyether composites, although other components and process parameters remain the same, the maturation time of Comparative Examples 2 and 3 is significantly prolonged. This reflects that the reactivity and nucleation ability of this type of commercial polyether composite under the TDI system are insufficient, making it difficult to achieve the rapid maturation effect of the system of the present invention.

[0091] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A polyurethane foam, characterized in that: It is obtained by reacting component A and component B, with the mass ratio of component A to component B being 100:30~70; By weight, component A comprises 10-50 parts of polyether polyol A1, 30-60 parts of polyether polyol A2, 20-50 parts of polyether polyol A3, 1.3-1.7 parts of catalyst, and 3-6 parts of foaming agent; Polyether polyol A1 uses propylene oxide and ethylene oxide as polymerizing monomers and is end-capped with ethylene oxide. The mass fraction of ethylene oxide in the polymerizing monomers is 20wt%~50wt%. The average functionality of polyether polyol A1 is 3~4 and the hydroxyl value is 24~42mgKOH / g. Polyether polyol A2 uses propylene oxide and ethylene oxide as polymer monomers and is end-capped with ethylene oxide. The mass fraction of ethylene oxide in the polymer monomers is 12wt%~18wt%. The average functionality of polyether polyol A2 is 3~5 and the hydroxyl value is 24~42mgKOH / g. Polyether polyol A3 uses propylene oxide and ethylene oxide as polymer monomers, grafts with styrene-acrylonitrile copolymer, and is end-capped with ethylene oxide. The mass fraction of ethylene oxide in the polymer monomers is 8wt%~12wt%, the average functionality of polyether polyol A3 is 3~5, and the hydroxyl value is 20~30mgKOH / g. Component B is selected from one of isocyanate B1, isocyanate B2, isocyanate B3, and isocyanate B4; Isocyanate B1 is a mixture of polymethylene polyphenyl polyisocyanate and toluene diisocyanate, with an NCO content of 39.5%. Isocyanate B2 is a mixture of polymethylene polyphenyl polyisocyanate and toluene diisocyanate, with an NCO content of 45.0%. Isocyanate B3 is a mixture of polymethylene polyphenyl polyisocyanate, diphenylmethane-4,4'-diisocyanate, and toluene diisocyanate, with an NCO content of 36.8%. Isocyanate B4 is a mixture of polymethylene polyphenyl polyisocyanate, diphenylmethane-4,4'-diisocyanate, polyol-modified isocyanate prepolymer and toluene diisocyanate, with an NCO content of 36.3%.

2. The polyurethane foam according to claim 1, characterized in that: The catalyst comprises one or more of the following: bis(2-dimethylaminoethyl) ether, N,N,N'-trimethyl-N'-hydroxyethyl bisaminoethyl ether, dimethylaminopropylamine, N,N'-dimethylethanolamine, bis(3-dimethylaminopropyl)aminoisopropanol, tetramethyldipropylenetriamine, pentamethyldiethylenetriamine, triethylenediamine, and 3,3'-iminobis(N,N-dimethylpropylamine); And / or, the foaming agent includes one or more of water, carbon dioxide, dichlorofluoroethane, butane, n-pentane, cyclopentane, and isopentane.

3. A polyurethane foam according to claim 1 or 2, characterized in that: Component A further includes other adjuvants, including one or more of diethanolamine, triethanolamine, ethylene glycol, diethylene glycol, glycerol, dipropylene glycol, 1,4-butanediol, trimethylolpropane, and pentaerythritol.

4. A polyurethane foam according to claim 1 or 2, characterized in that: The initiator of the polyether polyol is selected from small molecule alcohols with a functionality of 3 to 6.

5. A method for preparing polyurethane foam as described in any one of claims 1-4, characterized in that: include: Component A and component B are mixed and injected into a mold at a temperature of 50℃~80℃ for 60s~100s to obtain the polyurethane foam.

6. The application of a polyurethane foam as described in any one of claims 1-4 or a polyurethane foam prepared by the preparation method as described in claim 5 in automotive parts.

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