Polyurethane foam stabilizer and preparation method thereof

Abstract

The invention relates to the technical field of polyurethane foam, in particular to a polyurethane foam stabilizer and a preparation method thereof. The polyurethane foam stabilizer provided by the invention comprises the following materials in parts by weight: 50-70 parts of polyether modified polysiloxane, which is prepared from isocyanate-terminated unsaturated polyether and low-hydrogen silicone oil through hydrosilylation reaction; the auxiliary stable component is polyoxyethylene ether containing a furan ring, and the number-average molecular weight of the auxiliary stable component is 3000-5000; the functional additive is polyoxyethylene ether containing an azobenzene structure, and the number-average molecular weight of the functional additive is 1000-2000. According to the polyurethane foam obtained by the preparation method disclosed by the invention, the stability of the polyurethane foam can be effectively improved, and the thermal conductivity of the polyurethane foam can be reduced to a certain extent.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane foam, and in particular to a polyurethane foam stabilizer and a preparation method thereof. Background Art

[0002] Polyurethane foam stabilizer is a substance that can reduce the surface tension of polyurethane raw material mixture. During the period from foam rising to maturation, it prevents the thermodynamic instability of foam through surface tension, thereby promoting nucleation and stabilizing the raw materials in the pores and emulsification system, so that the obtained foam plastic products have excellent physical and mechanical properties.

[0003] The main functions of polyurethane foam stabilizers include emulsification, nucleation and stabilization. Emulsification refers to emulsifying the components into a uniform body to improve the stability and fluidity of the raw material system; nucleation refers to promoting the formation of bubbles during the foam formation process; stabilization is to adjust the size of the pores so that the foam has an ideal open-cell or closed-cell structure, thereby improving the mechanical properties, thermal insulation and sound insulation properties of the foam.

[0004] There are many types of existing polyurethane foam stabilizers, mainly including silicone foam stabilizers, non-silicone foam stabilizers and composite foam stabilizers. Among them, silicone foam stabilizers have polysiloxane as the main chain and copolyether as the side chain. They have strong emulsification and nucleation abilities and are widely used in the preparation of hard and soft polyurethane foams. The working principle of silicone foam stabilizers mainly depends on their special molecular structure. The polysiloxane main chain is hydrophobic and can reduce the surface tension of the system, while the copolyether side chain is hydrophilic and can enhance the interaction between the components, thereby improving the stability of the foam. However, the stability effect that can be achieved by existing polyurethane foam stabilizers is not good. Based on this, the present invention proposes a polyurethane foam stabilizer and a preparation method thereof. Summary of the invention

[0005] The purpose of the present invention is to provide a polyurethane foam stabilizer and a preparation method thereof. The stability of the polyurethane foam prepared by using the stabilizer is improved and the thermal conductivity of the polyurethane foam can be reduced to a certain extent.

[0006] In a first aspect, the present invention provides a polyurethane foam stabilizer, comprising the following raw materials in parts by weight: 50-70 parts of polyether-modified polysiloxane, prepared by hydrosilylation reaction of isocyanate-terminated unsaturated polyether and low-hydrogen silicone oil; 20-30 parts of auxiliary stabilizing component, which is polyoxyethylene ether containing furan ring and has a number average molecular weight of 3000-5000; The functional additive is 5-10 parts, which is a polyoxyethylene ether containing an azobenzene structure and has a number average molecular weight of 1000-2000.

[0007] Furthermore, the preparation method of the polyether-modified polysiloxane comprises: (1) Preparation of isocyanate-terminated unsaturated polyether: react allyl alcohol, ethylene oxide and propylene oxide in proportion under an alkaline catalyst at a temperature of 90-120°C and a pressure of ≤0.5 MPa to obtain an allyl-terminated polyether; add toluene diisocyanate for a capping reaction at a temperature of 60-80°C for 2-4 hours to generate an isocyanate-terminated polyether; (2) Preparation of low hydrogen silicone oil: Octamethylcyclotetrasiloxane, hexamethyldisiloxane and hydrogen silicone oil with a hydrogen content of ≥1% are reacted under the catalysis of an acidic ion exchange resin at a temperature of 50-70°C for 3-5 hours to obtain low hydrogen silicone oil with a hydrogen content of 0.3-0.8%; (3) Hydrosilylation: Mix the isocyanate-terminated unsaturated polyether and low-hydrogen silicone oil in a mass ratio of 4-6:1, add chloroplatinic acid catalyst, and react at 80-100°C for 2-4 hours to generate polyether-modified polysiloxane.

[0008] Furthermore, the alkaline catalyst is sodium hydroxide.

[0009] Furthermore, the weight ratio of allyl alcohol, ethylene oxide, propylene oxide, alkaline catalyst and toluene diisocyanate is (5-8): (15-20): (45-60): (0.5-1.5): (8-12).

[0010] Furthermore, the weight ratio of octamethylcyclotetrasiloxane, hexamethyldisiloxane, hydrogenated silicone oil and acidic ion exchange resin catalyst is (70-85): (10-15): (5-10): (2-3).

[0011] Furthermore, the acidic ion exchange resin includes any one of Amberlyst 15, Amberlyst 35 and D001.

[0012] Furthermore, the preparation method of the furan ring-containing polyoxyethylene ether comprises: adding furfurylamine and methyl acrylate to ethanol, heating to 60-70°C under nitrogen protection, dropping tetrabutylammonium bromide to react for 4-6 hours, removing ethanol by reduced pressure distillation to obtain a furan-acrylate intermediate, putting the intermediate and ethylene oxide into a high-pressure reactor at a molar ratio of 1:25-30, adding a KOH catalyst; gradually heating to 120-140°C, controlling the pressure to ≤0.8 MPa, reacting for 6-8 hours; filtering after neutralization, and dehydrating with a molecular sieve to obtain the product.

[0013] Furthermore, the weight ratio of furfurylamine, methyl acrylate, ethanol and tetrabutylammonium bromide is (10-15): (85-90): (280-320): (0.2-0.3).

[0014] Furthermore, the preparation method of the polyoxyethylene ether containing an azobenzene structure comprises: mixing 4-hydroxyazobenzene and metallic sodium in toluene, stirring at 70-80°C for 2-3 hours under nitrogen protection to generate a sodium salt active intermediate; transferring the active intermediate to an autoclave, slowly introducing ethylene oxide, controlling the temperature at 100-110°C and the pressure at ≤0.5 MPa, reacting for 3-4 hours, adding glacial acetic acid to neutralize to neutrality, and filtering to obtain the obtained product.

[0015] Furthermore, the weight ratio of the 4-hydroxyazobenzene, metallic sodium and toluene is (5-8):(0.1-0.3):100, and the molar ratio of the active intermediate to ethylene oxide is 1:15-20.

[0016] In a second aspect, the preparation method of the polyurethane foam stabilizer comprises the steps of mixing polyether-modified polysiloxane, furan ring-containing polyoxyethylene ether, and azobenzene polyoxyethylene ether in proportion to obtain a mixture, adding 0.5-1% triethylamine by weight relative to the mixture, and stirring at 60-70° C. for 2-3 hours to obtain the mixture.

[0017] The beneficial effects of the present invention are: The present invention prepares a polyether-modified polysiloxane with a special structure by carrying out a silylation reaction between an isocyanate-terminated unsaturated polyether and a low-hydrogen silicone oil. This structure not only improves the interface compatibility, but also significantly improves the uniformity of the pores; a polyoxyethylene ether containing a furan ring is introduced as an auxiliary stabilizing component, and the intermolecular cross-linking network is strengthened through π-π interaction, thereby enhancing the thermal stability; a polyoxyethylene ether containing an azobenzene structure is introduced as a functional additive, and the light response characteristics of the azobenzene group are utilized to achieve dynamic regulation of the pore structure; in addition, the stability and performance of the polyurethane foam are jointly improved through the synergistic effect of the polyether-modified polysiloxane, the polyoxyethylene ether containing a furan ring, and the polyoxyethylene ether containing an azobenzene structure.

[0018] The polyether-modified polysiloxane in the present invention combines the advantages of polyether and polysiloxane, has excellent flexibility and interface compatibility, and the isocyanate-terminated unsaturated polyether can react with the isocyanate group in the polyurethane system to form a chemical bond connection, thereby enhancing the interface bonding force. At the same time, the flexibility of the polysiloxane main chain helps to improve the uniformity of the pores and reduce the thermal conductivity.

[0019] The polyoxyethylene ether containing furan rings in the present invention forms a cross-linked network with other components in the polyurethane system through π-π interactions. This cross-linked structure can enhance the thermal stability of the foam and prevent the cells from collapsing or deforming at high temperatures. At the same time, the introduction of furan rings also helps to improve the weather resistance and aging resistance of the foam.

[0020] The azobenzene group in the present invention has a light-responsive property and can undergo conformational changes under light conditions. This conformational change can affect the structure and distribution of pores in the foam, thereby achieving dynamic regulation of the pores. By adjusting the light conditions and the content of the azobenzene group, the properties of the foam, such as density, hardness and thermal conductivity, can be precisely controlled.

[0021] In the present invention, the polyether-modified polysiloxane, the polyoxyethylene ether containing furan rings and the polyoxyethylene ether containing azobenzene structure have a synergistic effect. The polyether-modified polysiloxane provides main chain flexibility, which helps to improve the uniformity of the pores and reduce the thermal conductivity; the polyoxyethylene ether containing furan rings enhances thermal stability and prevents the collapse or deformation of the pores; and the polyoxyethylene ether containing azobenzene structure realizes dynamic regulation of the pores through light response characteristics. The three work together to make the polyurethane foam have excellent stability and performance. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that the hydrogen-containing silicone oil with a hydrogen content of ≥1% in the specific embodiment of the present invention is CR-F22H, produced by Hubei Kewode Chemical Co., Ltd.

[0024] Example 1 This embodiment provides a polyurethane foam stabilizer, including the following raw materials in parts by weight: 60 parts of polyether-modified polysiloxane, prepared by hydrosilylation reaction of isocyanate-terminated unsaturated polyether and low-hydrogen silicone oil; 25 parts of auxiliary stabilizing component, which is polyoxyethylene ether containing furan ring and has a number average molecular weight of 4000; 7 parts of functional additives, which are polyoxyethylene ether containing azobenzene structure and have a number average molecular weight of 1500; Wherein, the preparation method of polyether-modified polysiloxane comprises: (1) Preparation of isocyanate-terminated unsaturated polyether: Allyl alcohol, ethylene oxide and propylene oxide are reacted in proportion in the presence of an alkaline catalyst, sodium hydroxide, at a temperature of 105°C and a pressure of 0.5 MPa to obtain an allyl-terminated polyether; toluene diisocyanate is added for a capping reaction at a temperature of 70°C for 3 hours to generate an isocyanate-terminated polyether; the weight ratio of allyl alcohol, ethylene oxide, propylene oxide, alkaline catalyst and toluene diisocyanate is 6:17:48:1:10; (2) Preparation of low hydrogen silicone oil: Octamethylcyclotetrasiloxane, hexamethyldisiloxane and hydrogen silicone oil with a hydrogen content of ≥1% are reacted under the catalysis of an acidic ion exchange resin at a temperature of 60°C for 4 hours to obtain a low hydrogen silicone oil with a hydrogen content of 0.5%; the weight ratio of octamethylcyclotetrasiloxane, hexamethyldisiloxane, hydrogen silicone oil and acidic ion exchange resin catalyst is 80:12:7:2.5; the acidic ion exchange resin is D001 type; (3) Hydrosilylation: The isocyanate-terminated unsaturated polyether and low-hydrogen silicone oil were mixed in a mass ratio of 5:1, 0.21% of chloroplatinic acid catalyst was added relative to the total weight of the materials, and the mixture was reacted at 90°C for 3h to generate polyether-modified polysiloxane.

[0025] Among them, the preparation method of polyoxyethylene ether containing furan ring includes: adding furfurylamine and methyl acrylate to ethanol, heating to 65°C under nitrogen protection, adding tetrabutylammonium bromide dropwise to react for 5 hours, removing ethanol by reduced pressure distillation to obtain a furan-acrylate intermediate, putting the above intermediate and ethylene oxide into a high-pressure reactor at a molar ratio of 1:27, adding 0.3% KOH catalyst relative to the weight of the total material; gradually heating to 130°C, controlling the pressure to 0.8 MPa, and reacting for 7 hours; filtering after neutralization, and dehydrating with molecular sieves to obtain; the weight ratio of furfurylamine, methyl acrylate, ethanol and tetrabutylammonium bromide is 12:87:300:0.25.

[0026] The preparation method of the polyoxyethylene ether containing an azobenzene structure comprises: mixing 4-hydroxyazobenzene and metallic sodium in toluene, stirring at 75°C for 2.5 hours under nitrogen protection to generate a sodium salt active intermediate; transferring the active intermediate to an autoclave, slowly introducing ethylene oxide, controlling the temperature to 105°C and the pressure to 0.5 MPa, reacting for 3.5 hours, adding glacial acetic acid to neutralize to neutrality, and filtering to obtain the polyoxyethylene ether; the weight ratio of the 4-hydroxyazobenzene, metallic sodium and toluene is 6:0.2:100, and the molar ratio of the active intermediate to ethylene oxide is 1:17.

[0027] The preparation method of the polyurethane foam stabilizer comprises the steps of mixing polyether-modified polysiloxane, polyoxyethylene ether containing furan ring and azobenzene polyoxyethylene ether in proportion to obtain a mixture, adding 0.7% triethylamine relative to the weight of the mixture, and stirring at 65°C for 2.5 hours to obtain the mixture.

[0028] Example 2 This embodiment provides a polyurethane foam stabilizer, including the following raw materials in parts by weight: 50 parts of polyether-modified polysiloxane, prepared by hydrosilylation reaction of isocyanate-terminated unsaturated polyether and low-hydrogen silicone oil; 20 parts of auxiliary stabilizing component, which is polyoxyethylene ether containing furan ring and has a number average molecular weight of 3000; 5 parts of functional additives, which are polyoxyethylene ether containing azobenzene structure and have a number average molecular weight of 1000; Wherein, the preparation method of polyether-modified polysiloxane comprises: (1) Preparation of isocyanate-terminated unsaturated polyether: Allyl alcohol, ethylene oxide and propylene oxide are reacted in proportion in the presence of an alkaline catalyst, sodium hydroxide, at a temperature of 90°C and a pressure of 0.4 MPa to obtain an allyl-terminated polyether; toluene diisocyanate is added for a capping reaction at a temperature of 60°C for 2 hours to generate an isocyanate-terminated polyether; the weight ratio of allyl alcohol, ethylene oxide, propylene oxide, alkaline catalyst and toluene diisocyanate is 5:15:45:0.5:8; (2) Preparation of low hydrogen silicone oil: Octamethylcyclotetrasiloxane, hexamethyldisiloxane and hydrogen silicone oil with a hydrogen content of ≥1% were reacted under the catalysis of an acidic ion exchange resin at a temperature of 50°C for 3 hours to obtain low hydrogen silicone oil with a hydrogen content of 0.3%; the weight ratio of octamethylcyclotetrasiloxane, hexamethyldisiloxane, hydrogen silicone oil and acidic ion exchange resin catalyst was 70:10:5:2; the acidic ion exchange resin was Amberlyst 15; (3) Hydrosilylation: Mix the isocyanate-terminated unsaturated polyether and low-hydrogen silicone oil in a mass ratio of 4:1, add 0.21% of chloroplatinic acid catalyst relative to the total weight of the materials, and react at 80°C for 2h to generate polyether-modified polysiloxane; Among them, the preparation method of polyoxyethylene ether containing furan ring includes: adding furfurylamine and methyl acrylate to ethanol, heating to 60°C under nitrogen protection, adding tetrabutylammonium bromide dropwise for reaction for 4 hours, removing ethanol by reduced pressure distillation to obtain a furan-acrylate intermediate, putting the above intermediate and ethylene oxide into a high-pressure reactor at a molar ratio of 1:25, adding 0.3% KOH catalyst relative to the weight of the total material; gradually heating to 120°C, controlling the pressure to 0.8 MPa, and reacting for 6 hours; filtering after neutralization, and dehydrating with molecular sieves to obtain; the weight ratio of furfurylamine, methyl acrylate, ethanol and tetrabutylammonium bromide is 10:85:280:0.2.

[0029] The preparation method of the polyoxyethylene ether containing an azobenzene structure comprises: mixing 4-hydroxyazobenzene and metallic sodium in toluene, stirring at 70°C for 2 hours under nitrogen protection to generate a sodium salt active intermediate; transferring the active intermediate to an autoclave, slowly introducing ethylene oxide, controlling the temperature to 100°C and the pressure to 0.5 MPa, reacting for 3 hours, adding glacial acetic acid to neutralize to neutrality, and filtering to obtain the polyoxyethylene ether; the weight ratio of the 4-hydroxyazobenzene, metallic sodium and toluene is 5:0.1:100, and the molar ratio of the active intermediate to ethylene oxide is 1:15.

[0030] The preparation method of the polyurethane foam stabilizer comprises the steps of mixing polyether-modified polysiloxane, polyoxyethylene ether containing furan ring and azobenzene polyoxyethylene ether in proportion to obtain a mixture, adding 0.5% triethylamine by weight relative to the mixture, and stirring at 60°C for 2 hours to obtain the mixture.

[0031] Example 3 This embodiment provides a polyurethane foam stabilizer, including the following raw materials in parts by weight: 70 parts of polyether-modified polysiloxane, prepared by hydrosilylation reaction of isocyanate-terminated unsaturated polyether and low-hydrogen silicone oil; 30 parts of an auxiliary stabilizing component, which is a polyoxyethylene ether containing a furan ring and has a number average molecular weight of 5000; 10 parts of functional additives, which are polyoxyethylene ether containing azobenzene structure and have a number average molecular weight of 2000; Wherein, the preparation method of polyether-modified polysiloxane comprises: (1) Preparation of isocyanate-terminated unsaturated polyether: Allyl alcohol, ethylene oxide and propylene oxide are reacted in proportion in the presence of an alkaline catalyst, sodium hydroxide, at a temperature of 120°C and a pressure of 0.5 MPa to obtain an allyl-terminated polyether; toluene diisocyanate is added for a capping reaction at a temperature of 80°C for 4 hours to generate an isocyanate-terminated polyether; the weight ratio of allyl alcohol, ethylene oxide, propylene oxide, alkaline catalyst and toluene diisocyanate is 8:20:60:1.5:12; (2) Preparation of low hydrogen silicone oil: Octamethylcyclotetrasiloxane, hexamethyldisiloxane and hydrogen silicone oil with a hydrogen content of ≥1% were reacted under the catalysis of an acidic ion exchange resin at a temperature of 70°C for 5 hours to obtain low hydrogen silicone oil with a hydrogen content of 0.8%; the weight ratio of octamethylcyclotetrasiloxane, hexamethyldisiloxane, hydrogen silicone oil and acidic ion exchange resin catalyst was 85:15:10:3; the acidic ion exchange resin was Amberlyst 35; (3) Hydrosilylation: Mix the isocyanate-terminated unsaturated polyether and low-hydrogen silicone oil in a mass ratio of 6:1, add 0.21% chloroplatinic acid catalyst relative to the total weight of the materials, and react at 100°C for 4 hours to generate a polyether-modified polysiloxane; Among them, the preparation method of polyoxyethylene ether containing furan ring includes: adding furfurylamine and methyl acrylate to ethanol, heating to 70°C under nitrogen protection, adding tetrabutylammonium bromide dropwise to react for 6 hours, removing ethanol by reduced pressure distillation to obtain a furan-acrylate intermediate, putting the above intermediate and ethylene oxide into a high-pressure reactor at a molar ratio of 1:30, adding 0.3% KOH catalyst relative to the weight of the total material; gradually heating to 140°C, controlling the pressure to 0.7MPa, and reacting for 8 hours; filtering after neutralization, and dehydrating with molecular sieves to obtain; the weight ratio of furfurylamine, methyl acrylate, ethanol and tetrabutylammonium bromide is 15:90:320:0.3.

[0032] The preparation method of the polyoxyethylene ether containing an azobenzene structure comprises: mixing 4-hydroxyazobenzene and metallic sodium in toluene, stirring at 80°C for 3 hours under nitrogen protection to generate a sodium salt active intermediate; transferring the active intermediate to an autoclave, slowly introducing ethylene oxide, controlling the temperature to 110°C and the pressure to 0.5 MPa, reacting for 4 hours, adding glacial acetic acid to neutralize to neutrality, and filtering to obtain the polyoxyethylene ether; the weight ratio of the 4-hydroxyazobenzene, metallic sodium and toluene is 8:0.3:100, and the molar ratio of the active intermediate to ethylene oxide is 1:20.

[0033] The preparation method of the polyurethane foam stabilizer comprises the steps of mixing polyether-modified polysiloxane, polyoxyethylene ether containing furan ring and azobenzene polyoxyethylene ether in proportion to obtain a mixture, adding 1% triethylamine relative to the weight of the mixture, and stirring at 70°C for 3 hours to obtain the mixture.

[0034] Example 4 This embodiment provides a polyurethane foam stabilizer, including the following raw materials in parts by weight: 50 parts of polyether-modified polysiloxane, prepared by hydrosilylation reaction of isocyanate-terminated unsaturated polyether and low-hydrogen silicone oil; 30 parts of auxiliary stabilizing component, which is polyoxyethylene ether containing furan ring and has a number average molecular weight of 3000; 5 parts of functional additives, which are polyoxyethylene ether containing azobenzene structure and have a number average molecular weight of 2000; Wherein, the preparation method of polyether-modified polysiloxane comprises: (1) Preparation of isocyanate-terminated unsaturated polyether: Allyl alcohol, ethylene oxide and propylene oxide are reacted in proportion in the presence of an alkaline catalyst, sodium hydroxide, at a temperature of 90°C and a pressure of 0.5 MPa to obtain an allyl-terminated polyether; toluene diisocyanate is added for a capping reaction at a temperature of 80°C for 2 hours to generate an isocyanate-terminated polyether; the weight ratio of allyl alcohol, ethylene oxide, propylene oxide, alkaline catalyst and toluene diisocyanate is 8:15:60:1.5:12; (2) Preparation of low hydrogen silicone oil: Octamethylcyclotetrasiloxane, hexamethyldisiloxane and hydrogen silicone oil with a hydrogen content of ≥1% were reacted under the catalysis of an acidic ion exchange resin at a temperature of 70°C for 3 hours to obtain a low hydrogen silicone oil with a hydrogen content of 0.8%; the weight ratio of octamethylcyclotetrasiloxane, hexamethyldisiloxane, hydrogen silicone oil and acidic ion exchange resin catalyst was 70:10:10:3; the acidic ion exchange resin was Amberlyst 15; (3) Hydrosilylation: Mix the isocyanate-terminated unsaturated polyether and low-hydrogen silicone oil in a mass ratio of 4:1, add 0.21% of chloroplatinic acid catalyst relative to the total weight of the materials, and react at 100°C for 4 hours to generate a polyether-modified polysiloxane; Among them, the preparation method of polyoxyethylene ether containing furan ring includes: adding furfurylamine and methyl acrylate to ethanol, heating to 60°C under nitrogen protection, adding tetrabutylammonium bromide dropwise for reaction for 6 hours, removing ethanol by reduced pressure distillation to obtain a furan-acrylate intermediate, putting the above intermediate and ethylene oxide into a high-pressure reactor at a molar ratio of 1:25, adding 0.3% KOH catalyst relative to the weight of the total material; gradually heating to 140°C, controlling the pressure to 0.8 MPa, and reacting for 8 hours; filtering after neutralization, and dehydrating with molecular sieves to obtain; the weight ratio of furfurylamine, methyl acrylate, ethanol and tetrabutylammonium bromide is 15:85:320:0.2.

[0035] The preparation method of the polyoxyethylene ether containing an azobenzene structure comprises: mixing 4-hydroxyazobenzene and metallic sodium in toluene, stirring at 70°C for 3 hours under nitrogen protection to generate a sodium salt active intermediate; transferring the active intermediate to an autoclave, slowly introducing ethylene oxide, controlling the temperature to 100°C and the pressure to 0.5 MPa, reacting for 4 hours, adding glacial acetic acid to neutralize to neutrality, and filtering to obtain the polyoxyethylene ether; the weight ratio of the 4-hydroxyazobenzene, metallic sodium and toluene is 5:0.3:100, and the molar ratio of the active intermediate to ethylene oxide is 1:20.

[0036] The preparation method of the polyurethane foam stabilizer comprises the steps of mixing polyether-modified polysiloxane, polyoxyethylene ether containing furan ring and azobenzene polyoxyethylene ether in proportion to obtain a mixture, adding 0.5% triethylamine by weight relative to the mixture, and stirring at 70°C for 2 hours to obtain the mixture.

[0037] Comparative Example 1 Adjustments were made on the basis of Example 1. The difference from Example 1 was that the polyether-modified polysiloxane in Comparative Example 1 was replaced by ordinary polydimethylsiloxane, CAS No.: 156327-07-0, model P433351 (Aladdin Reagent Co., Ltd.).

[0038] Comparative Example 2 Adjustments were made on the basis of Example 1. The difference from Example 1 was that the auxiliary stabilizing component in Comparative Example 2 was replaced by common polyoxyethylene ether with a number average molecular weight of 4,000.

[0039] Comparative Example 3 Adjustments were made based on Example 1. The difference from Example 1 was that the auxiliary stabilizing component was eliminated in Comparative Example 3, and the remaining components were the same as those in Example 1.

[0040] Comparative Example 4 Adjustments were made on the basis of Example 1. The difference from Example 1 was that the functional additive in Comparative Example 4 was replaced by common polyoxyethylene ether with a number average molecular weight of 4000.

[0041] Comparative Example 5 Adjustments were made on the basis of Example 1. The difference from Example 1 was that the functional additives were eliminated in Comparative Example 5, and the remaining components were the same as those in Example 1.

[0042] Comparative Example 6 Adjustments were made on the basis of Example 1. The difference from Example 1 was that the auxiliary stabilizing component and the functional additive in Comparative Example 6 were replaced with common polyoxyethylene ether with a number average molecular weight of 4,000.

[0043] The performance tests of the polyurethane foams prepared in Examples 1-4 and Comparative Examples 1-6 are as follows: Polyurethane foam was prepared by the following polyurethane foaming formula in parts by weight: 80 parts of polyether polyol 4110 (Xuzhou Yihuiyang New Materials Co., Ltd.), 20 parts of polyether polyol 635 (Langfang Huayu Innovation Technology Co., Ltd.), 1.5 parts of water, 1.3 parts of DMP30, 1.5 parts of foam stabilizer, 13 parts of cyclopentane, and 143 parts of MDI; the foam stabilizer was the polyurethane foam stabilizer prepared in the examples and comparative examples.

[0044] Thermal conductivity: The above formula is mixed and injected into a 1100×300×50 mold through a high-pressure foaming machine for closed-mold foaming. The foam core density is 30kg / m 3 , measured using a thermal conductivity measuring device based on JIS A1412.

[0045] Stability: Mix the above formulas and place them aside to count whether the solution is stratified or turbid. Keep a timer and take the average value of 5 groups for each group.

[0046] The test results are shown in Table 1.

[0047] Table 1 Test results

[0048] According to the above content, after using ordinary polydimethylsiloxane in comparative example 1, the thermal conductivity increased by 13.6% and the emulsification time was shortened by 52.2%, indicating that the isocyanate-terminated polyether modified structure significantly improved the interfacial compatibility and pore uniformity. The thermal conductivity of comparative example 2 increased by 10.8%, and the emulsification time was shortened by 30.2%; the thermal conductivity of comparative example 3 increased by 18.2%, and the emulsification time was shortened by 64.9%, indicating that the polyoxyethylene ether containing furan ring strengthened the intermolecular cross-linking network through π-π interaction. The thermal conductivity of comparative example 4 increased by 8.5%, and the emulsification time was shortened by 18.5%; the thermal conductivity of comparative example 5 increased by 14.2%, and the emulsification time was shortened by 39.5%, proving that the light response characteristics of the azobenzene group can dynamically adjust the pore structure. The thermal conductivity of Comparative Example 6 increased by 29.0%, and the emulsification time was shortened by 72.7%, which verified the synergistic effect of the ternary system, in which the polyether-modified polysiloxane provided main chain flexibility, the furan ring auxiliary component enhanced thermal stability, and the azobenzene additive realized dynamic regulation of the pores.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. All technical solutions and improvements that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A polyurethane foam stabilizer, characterized in that It includes the following raw materials in parts by weight: 50-70 parts of polyether-modified polysiloxane, prepared by hydrosilylation reaction of isocyanate-terminated unsaturated polyether and low-hydrogen silicone oil; 20-30 parts of auxiliary stabilizing component, which is polyoxyethylene ether containing furan ring and has a number average molecular weight of 3000-5000; The functional additive is 5-10 parts, which is a polyoxyethylene ether containing an azobenzene structure and has a number average molecular weight of 1000-2000.

2. A polyurethane foam stabilizer according to claim 1, characterized in that: The preparation method of the polyether-modified polysiloxane comprises: (1) Preparation of isocyanate-terminated unsaturated polyether: allyl alcohol, ethylene oxide and propylene oxide are reacted in proportion under an alkaline catalyst to obtain an allyl-terminated polyether; toluene diisocyanate is added to carry out a capping reaction to generate an isocyanate-terminated polyether; (2) Preparation of low hydrogen silicone oil: Octamethylcyclotetrasiloxane, hexamethyldisiloxane and hydrogen silicone oil with a hydrogen content of ≥1% are reacted under the catalysis of an acidic ion exchange resin to obtain low hydrogen silicone oil; (3) Hydrosilylation: Mix the isocyanate-terminated unsaturated polyether and low-hydrogen silicone oil in a mass ratio of 4-6:1, add chloroplatinic acid catalyst to react, and generate polyether-modified polysiloxane.

3. A polyurethane foam stabilizer according to claim 2, characterized in that: The weight ratio of allyl alcohol, ethylene oxide, propylene oxide, alkaline catalyst and toluene diisocyanate is (5-8): (15-20): (45-60): (0.5-1.5): (8-12).

4. A polyurethane foam stabilizer according to claim 2, characterized in that: The weight ratio of octamethylcyclotetrasiloxane, hexamethyldisiloxane, hydrogenated silicone oil and acidic ion exchange resin catalyst is (70-85): (10-15): (5-10): (2-3).

5. A polyurethane foam stabilizer according to claim 2, characterized in that: The acidic ion exchange resin includes any one of Amberlyst 15, Amberlyst 35 and D001.

6. A polyurethane foam stabilizer according to claim 1, characterized in that: The preparation method of the furan ring-containing polyoxyethylene ether comprises: adding furfurylamine and methyl acrylate into ethanol, heating to 60-70°C under nitrogen protection, dropping tetrabutylammonium bromide for reaction for 4-6 hours, removing ethanol by reduced pressure distillation to obtain a furan-acrylate intermediate, adding the intermediate and ethylene oxide in a 1:25-30 molar ratio into a high-pressure reactor, adding a catalyst for reaction, filtering after neutralization, and dehydrating with a molecular sieve to obtain the polyoxyethylene ether.

7. A polyurethane foam stabilizer according to claim 6, characterized in that: The weight ratio of furfurylamine, methyl acrylate, ethanol and tetrabutylammonium bromide is (10-15): (85-90): (280-320): (0.2-0.3).

8. A polyurethane foam stabilizer according to claim 1, characterized in that: The preparation method of the polyoxyethylene ether containing an azobenzene structure comprises: mixing 4-hydroxyazobenzene and metallic sodium in toluene, stirring at 70-80° C. for 2-3 hours under nitrogen protection to generate a sodium salt active intermediate; transferring the active intermediate to an autoclave, slowly introducing ethylene oxide, controlling the temperature at 100-110° C. and the pressure at ≤0.5 MPa, reacting for 3-4 hours, adding glacial acetic acid to neutralize to neutrality, and filtering to obtain the polyoxyethylene ether.

9. A polyurethane foam stabilizer according to claim 8, characterized in that: The weight ratio of the 4-hydroxyazobenzene, metallic sodium and toluene is (5-8):(0.1-0.3):100, and the molar ratio of the active intermediate to ethylene oxide is 1:15-20.

10. A method for preparing the polyurethane foam stabilizer according to any one of claims 1 to 9, characterized in that: The steps include mixing polyether-modified polysiloxane, polyoxyethylene ether containing furan ring and azobenzene polyoxyethylene ether in proportion to obtain a mixture, adding 0.5-1% of triethylamine relative to the weight of the mixture, and stirring at 60-70°C for 2-3 hours to obtain the mixture.

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