Polyurethane foam stabilizer and preparation method thereof
By introducing Diels-Alder dynamic covalent bond structural units into the polysiloxane backbone, the problem of insufficient stability of polyurethane foam was solved, and better cell structure and mechanical stability were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ANHUI MAICHEN TECHNOLOGY CO LTD
- Filing Date
- 2026-02-28
- Publication Date
- 2026-05-12
AI Technical Summary
Existing polyurethane foams lack stability, are prone to collapse, and have poor cell uniformity. Traditional foam stabilizers are not compatible with oil-phase raw materials and cannot effectively stabilize the cell walls.
Polyether-grafted polysiloxanes are generated by reacting allyl polyethers containing Diels-Alder bonds with low-hydrogen silicone oils under a platinum catalyst. By introducing Diels-Alder dynamic covalent bond structural units into the polysiloxane backbone, the compatibility with aromatic oil phase raw materials is enhanced, and a close directional arrangement is achieved.
It improves the emulsification effect and cell structure integrity of polyurethane foam, promotes the formation of uniform and fine cells, and significantly enhances the mechanical stability of foam products.
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Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of polyurethane foam stabilizers, specifically relating to a polyurethane foam stabilizer and its preparation method. Background Technology
[0002] Polyurethane foam is a material formed from multiple raw materials through complex chemical reactions in a very short time, transforming from a liquid to a colloid and finally into a polymer. This process encompasses several key stages, including foaming and curing, where the stability and uniformity of the system are crucial. During this process, foam stabilizers (also known as foam levelers) play an irreplaceable regulatory role. They ensure uniform foaming and structurally stable foam products by reducing the surface tension of the system, emulsifying the components, stabilizing bubble growth, and controlling the final cell structure. Without the regulation of foam stabilizers, the foam is highly susceptible to defects such as collapse, coarse pores, and cracking.
[0003] Currently, the most widely used foam stabilizers in the polyurethane industry are polyether-modified polysiloxane surfactants. These molecules typically consist of a hydrophobic polysiloxane backbone and hydrophilic polyether side chains. By precisely designing the type, length, number, and connection method of these two chain segments, their hydrophilic-lipophilic balance can be adjusted to adapt to different foaming systems. For example, in the production of flexible foam, an ideal foam stabilizer needs to fully emulsify the raw materials and stabilize the newly formed cells in the early stages of foaming, and promote timely "cell opening" in the later stages to ensure the softness and air permeability of the foam.
[0004] For optimizing the performance of foam levelers, most existing technologies focus on modifying and adjusting polyether segments. For example, some patented technologies utilize the different hydrophilic-lipophilic balance values of two polyether-modified polysiloxane components with different degrees of polymerization and molecular weights to improve overall emulsification performance. Other technologies emphasize increasing the end-capping rate of polyether segments and controlling the narrowness of their molecular weight distribution, aiming to eliminate the influence of residual hydroxyl groups and enhance the chemical stability of the foam leveler itself, thereby improving the foam leveling effect. Furthermore, precisely controlling the molecular weight ratio of hydrogen-containing silicone oil and allyl polyether, as well as the conversion rate of the hydrosilylation reaction, has also become an effective means of designing general-purpose foam levelers.
[0005] While the aforementioned techniques based on polyether segment modification have made some progress, significant limitations remain. These improvements primarily focus on the polyether segments as hydrophilic groups, aiming to enhance their ability to solubilize and emulsify aqueous phases or polar components, but generally neglect targeted functionalization modifications to the polysiloxane backbone as a lipophilic group. The oil-phase raw materials of polyurethane flexible foam, such as toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and their modified forms, are all aromatic compounds containing benzene rings and possess specific polarity. However, the polysiloxane backbone (Si-O-Si structure) of traditional foam stabilizers is inherently more compatible with non-polar alkanes, and its compatibility with the aforementioned aromatic oil-phase raw materials is generally poor. This insufficient compatibility makes it difficult for foam stabilizer molecules to achieve the most effective directional adsorption and close arrangement at the oil-water (or oil-solid) interface of the foaming system, thereby weakening its core functions of reducing interfacial tension and stabilizing cell walls, resulting in emulsification and foam stabilization effects failing to meet expectations.
[0006] This defect is further amplified in the complex foaming environment of flexible foam. The flexible foam reaction produces a large number of insoluble substituted urea particles. If the hydrophobic segments of the foam stabilizer have poor compatibility with these particles, they cannot effectively wet and disperse them, causing them to accumulate locally on the cell walls, disrupting the continuity of the film, and ultimately leading to cell rupture and overall collapse.
[0007] Therefore, there is an urgent need in this field for a new type of foam leveling agent to solve the problems of insufficient stability, easy collapse, and poor cell uniformity of polyurethane foam in the prior art. Summary of the Invention
[0008] The purpose of this invention is to provide a polyurethane foam stabilizer and its preparation method to solve the problems of insufficient stability, easy collapse, and poor cell uniformity of polyurethane foam.
[0009] The objective of this invention can be achieved through the following technical solutions: The first aspect of the present invention provides a polyurethane foam stabilizer, wherein the polyurethane foam stabilizer is a polyether-grafted polysiloxane generated by reacting an allyl polyether containing Diels-Alder bonds with a low-hydrogen silicone oil under the catalysis of a platinum catalyst.
[0010] Furthermore, the allyl polyether containing Diels-Alder bonds is prepared by the Diels-Alder reaction using allyl-furfuryl glycerol ether and multifunctional maleimide as reactants to obtain an allyl polyether containing double bonds with Diels-Alder bonds.
[0011] Furthermore, the allyl polyether containing Diels-Alder bonds is prepared by the following steps: Step S1: Mix furfuryl alcohol, sodium hydroxide, and water. Under nitrogen protection, heat to 85-90℃ and add allyl glycidyl ether dropwise. After the addition is complete, keep the temperature constant and continue stirring for 3-4 hours. After the reaction is complete, add cation exchange resin to neutralize the reaction until neutral. Filter and distill the filtrate under reduced pressure to remove water and unreacted substances. Cool to room temperature to obtain allyl-furfuryl ether. Under alkaline conditions, furfuryl alcohol and allyl glycidyl ether form a stable ether bond through a ring-opening reaction to obtain allyl-furfuryl ether.
[0012] Step S2: Allyl-furfuryl glycerol ether and polyfunctional maleimide are added to chloroform and stirred at 60-70℃ for 12-24 h to obtain allyl polyether containing Diels-Alder bonds.
[0013] Furthermore, the multifunctional maleimide is at least one of 4,4'-bismaleimide diphenylmethane and tris(2-maleimide ethyl)amine.
[0014] Furthermore, the mass ratio of allyl-furfuryl glycerol ether to multifunctional maleimide is 3.5:3.8-7. Without significantly increasing the system viscosity, the mixed use of maleimides with different functionalities allows the trifunctional component to act as a dynamic crosslinking point, contributing to the construction of a stable and repairable network framework; the bifunctional component acts as a flexible connecting chain, endowing the network with suitable elasticity. Under the action of foaming heat, this hybrid network exhibits superior dynamic reversibility, effectively repairing cell wall defects and guiding the formation of a three-dimensional cell structure with more complete pore walls and more uniform dimensions.
[0015] Furthermore, the mass ratio of allyl-furfuryl glycerol ether to 4,4'-bismaleimide diphenylmethane is 3.5:5.8-6.
[0016] Furthermore, the mass ratio of allyl-furfuryl glycerol ether to tris(2-maleimide ethyl)amine is 3.5:3.8-4.
[0017] Further, in step S1, the molar ratio of furfuryl alcohol to allyl glycidyl ether is 1:1; the ratio of furfuryl alcohol, sodium hydroxide and water is 2.5-3g:0.1g:10mL; and in step S2, the ratio of allyl-furfuryl ether to chloroform is 1g:10-15mL.
[0018] Furthermore, the hydrogen content of the low-hydrogen silicone oil is 0.1%–0.3% by mass, and the viscosity is 20–100 mPa·s.
[0019] The low-hydrogen-content silicone oil is prepared through the following steps: High-hydrogen-content silicone oil, octamethylcyclotetrasiloxane, hexamethyldisiloxane, and concentrated sulfuric acid were mixed and reacted at 40-60℃ for 6-8 hours. After the reaction was complete, water was added for two separate-phase washings to remove the acidic water. Sodium bicarbonate powder was slowly added, and the acid was neutralized at 40-50℃ (until pH paper showed neutrality). The mixture was filtered to remove insoluble sodium bicarbonate and sodium sulfate, and washed again with water. After washing, the mixture was distilled under vacuum at 120℃ to remove low-boiling-point substances. Finally, the mixture was filtered to obtain low-hydrogen-content silicone oil. The high-hydrogen-content silicone oil has a mass fraction of 1.6%, and the mass ratio of the high-hydrogen-content silicone oil, octamethylcyclotetrasiloxane, hexamethyldisiloxane, and concentrated sulfuric acid is 30:170:10-30:1. The lower the amount of hexamethyldisiloxane used, the higher the viscosity and the larger the molecular weight. This method is not suitable for the preparation of foam levelers.
[0020] This invention provides a method for preparing a polyurethane foam stabilizer, comprising the following steps: Allyl polyether containing Diels-Alder bonds is added to an organic solvent. Under nitrogen protection, a platinum catalyst is added, the temperature is raised to 50-52℃, and the mixture is stirred for 30-60 minutes. Then, low-hydrogen silicone oil is added. After the addition is complete, the temperature is set to 60-70℃, and the mixture is stirred for 24-36 hours. After the reaction is complete, toluene is removed by rotary evaporation to obtain a polyurethane foam stabilizer.
[0021] Furthermore, the amount of platinum catalyst added is 30-40 ppm of the total mass of allyl polyether containing Diels-Alder bonds and low-hydrogen silicone oil; the mass ratio of allyl polyether containing Diels-Alder bonds to low-hydrogen silicone oil is 60-70:100; and the organic solvent is toluene.
[0022] The beneficial effects of this invention are: The beneficial effects provided by this invention are as follows: This invention provides a polyurethane foam stabilizer, which is a polyether-grafted polysiloxane generated by reacting an allyl polyether containing Diels-Alder bonds with a low-hydrogen silicone oil under the catalysis of a platinum catalyst. By innovatively introducing Diels-Alder dynamic covalent bond structural units into the hydrophobic backbone of the polysiloxane, the hydrophobic properties of the foam stabilizer molecule are fundamentally altered. The introduced aromatic components, such as the benzene ring in the furan and multifunctional maleimide structures, significantly enhance the compatibility and affinity of the foam stabilizer with aromatic oil-phase raw materials (such as TDI and MDI) in the polyurethane flexible foam system. This solves the problem of generally poor compatibility between traditional polysiloxane chains and oil-phase raw materials, enabling the foam stabilizer molecules to achieve a tighter and more efficient directional arrangement at the oil-water and oil-solid interfaces of the foaming system, thereby providing superior initial interface stability.
[0023] The foam stabilizer described in this invention not only more effectively emulsifies raw materials and stabilizes initial bubbles, but also actively maintains the integrity of the cell structure through dynamic chemical action throughout the foaming process. Its ultimate effect is that, in the production of flexible polyurethane foam, it promotes the formation of a more uniform and delicate cell structure and significantly improves the mechanical stability of the foam product. Detailed Implementation
[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0025] Obviously, the following description is merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios without any inventive effort. Furthermore, it is understood that although the effort involved in such development may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.
[0026] However, there may be instances where unnecessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of essentially the same structure may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to enable those skilled in the art to fully understand this application and is not intended to limit the subject matter of the claims.
[0027] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions, and all technical features and optional technical features of this application can be combined to form new technical solutions.
[0028] The following is a detailed description of a polyurethane foam stabilizer and its preparation method according to an embodiment of this application.
[0029] The following is a detailed description with reference to specific examples.
[0030] Example 1
[0031] This embodiment provides a polyurethane foam stabilizer, which is a polyether-grafted polysiloxane generated by reacting allyl polyether containing Diels-Alder bonds with low-hydrogen silicone oil under the catalysis of a platinum catalyst.
[0032] The allyl polyether containing Diels-Alder bonds is prepared through the following steps: Step S1: Mix furfuryl alcohol, sodium hydroxide, and water. Under nitrogen protection, heat to 90°C and add allyl glycidyl ether dropwise. After the addition is complete, keep the temperature constant and continue stirring for 3 hours. After the reaction is complete, add cation exchange resin to neutralize the reaction until neutral. Filter and distill the filtrate under reduced pressure to remove water and unreacted substances. Cool to room temperature to obtain allyl-furfuryl ether. The molar ratio of furfuryl alcohol to allyl glycidyl ether is 1:1; the molar ratio of furfuryl alcohol, sodium hydroxide, and water is 2.5g:0.1g:10mL. Step S2: Allyl-furfuryl glycerol ether and polyfunctional maleimide were added to chloroform and stirred at 65°C for 20 h to obtain allyl polyether containing Diels-Alder bonds. The ratio of allyl-furfuryl glycerol ether to chloroform was 1 g: 10 mL.
[0033] The multifunctional maleimide is 4,4'-bismaleimide diphenylmethane and tris(2-maleimide ethyl)amine. The mass ratio of allyl-furfuryl glycerol ether, 4,4'-bismaleimide diphenylmethane and tris(2-maleimide ethyl)amine is 3.5:3:3.5.
[0034] The low-hydrogen-content silicone oil is prepared through the following steps: High-hydrogen-content silicone oil, octamethylcyclotetrasiloxane, hexamethyldisiloxane, and concentrated sulfuric acid were mixed and reacted at 50°C for 7 hours. After the reaction was completed, water was added for two separate washings to remove the acidic water. Sodium bicarbonate powder was slowly added, and the acid was neutralized at 40-50°C (until pH paper showed neutrality). The mixture was filtered to remove insoluble sodium bicarbonate and sodium sulfate, and washed again with water. After washing, the mixture was distilled under vacuum at 120°C to remove low-boiling-point substances, and finally filtered to obtain low-hydrogen-content silicone oil. The high-hydrogen-content silicone oil had a mass fraction of 1.6%, and the mass ratio of high-hydrogen-content silicone oil, octamethylcyclotetrasiloxane, hexamethyldisiloxane, and concentrated sulfuric acid was 30:170:2:1. The low-hydrogen-content silicone oil had a hydrogen mass fraction of 0.2% and a viscosity of 48 mPa·s.
[0035] The preparation method of this polyurethane foam stabilizer includes the following steps: The above-mentioned allyl polyether containing Diels-Alder bonds was added to toluene. Under nitrogen protection, a platinum catalyst was added, the temperature was raised to 50°C, and the mixture was stirred for 60 min. Then, the above-mentioned low-hydrogen silicone oil was added. After the addition was complete, the temperature was set to 62°C, and the mixture was stirred for 30 h. After the reaction was completed, the toluene was removed by rotary evaporation to obtain a polyurethane foam stabilizer. The amount of platinum catalyst added was 30 ppm of the total mass of the allyl polyether containing Diels-Alder bonds and the low-hydrogen silicone oil. The mass ratio of the allyl polyether containing Diels-Alder bonds to the low-hydrogen silicone oil was 65:100.
[0036] Example 2
[0037] This embodiment provides a polyurethane foam stabilizer, which is a polyether-grafted polysiloxane generated by reacting allyl polyether containing Diels-Alder bonds with low-hydrogen silicone oil under the catalysis of a platinum catalyst.
[0038] The allyl polyether containing Diels-Alder bonds is prepared through the following steps: Step S1: Mix furfuryl alcohol, sodium hydroxide, and water. Under nitrogen protection, heat to 90°C and add allyl glycidyl ether dropwise. After the addition is complete, keep the temperature constant and continue stirring for 3 hours. After the reaction is complete, add cation exchange resin to neutralize the reaction until neutral. Filter and distill the filtrate under reduced pressure to remove water and unreacted substances. Cool to room temperature to obtain allyl-furfuryl ether. The molar ratio of furfuryl alcohol to allyl glycidyl ether is 1:1; the molar ratio of furfuryl alcohol, sodium hydroxide, and water is 2.5g:0.1g:10mL. Step S2: Allyl-furfuryl glycerol ether and polyfunctional maleimide were added to chloroform and stirred at 65°C for 20 h to obtain allyl polyether containing Diels-Alder bonds. The ratio of allyl-furfuryl glycerol ether to chloroform was 1 g: 10 mL.
[0039] The multifunctional maleimide is 4,4'-bismaleimide diphenylmethane and tris(2-maleimide ethyl)amine. The mass ratio of allyl-furfuryl glycerol ether, 4,4'-bismaleimide diphenylmethane and tris(2-maleimide ethyl)amine is 3.5:1.5:5.2:.
[0040] The low-hydrogen-content silicone oil is prepared through the following steps: High-hydrogen-content silicone oil, octamethylcyclotetrasiloxane, hexamethyldisiloxane, and concentrated sulfuric acid were mixed and reacted at 50°C for 7 hours. After the reaction was completed, water was added for two separate washings to remove the acidic water. Sodium bicarbonate powder was slowly added, and the acid was neutralized at 40-50°C (until pH paper showed neutrality). The mixture was filtered to remove insoluble sodium bicarbonate and sodium sulfate, and washed again with water. After washing, the mixture was distilled under vacuum at 120°C to remove low-boiling-point substances, and finally filtered to obtain low-hydrogen-content silicone oil. The high-hydrogen-content silicone oil had a mass fraction of 1.6%, and the mass ratio of high-hydrogen-content silicone oil, octamethylcyclotetrasiloxane, hexamethyldisiloxane, and concentrated sulfuric acid was 30:170:2:1. The low-hydrogen-content silicone oil had a hydrogen mass fraction of 0.2% and a viscosity of 48 mPa·s.
[0041] The preparation method of this polyurethane foam stabilizer includes the following steps: The above-mentioned allyl polyether containing Diels-Alder bonds was added to toluene. Under nitrogen protection, a platinum catalyst was added, the temperature was raised to 50°C, and the mixture was stirred for 60 min. Then, the above-mentioned low-hydrogen silicone oil was added. After the addition was complete, the temperature was set to 62°C, and the mixture was stirred for 30 h. After the reaction was completed, the toluene was removed by rotary evaporation to obtain a polyurethane foam stabilizer. The amount of platinum catalyst added was 30 ppm of the total mass of the allyl polyether containing Diels-Alder bonds and the low-hydrogen silicone oil. The mass ratio of the allyl polyether containing Diels-Alder bonds to the low-hydrogen silicone oil was 65:100.
[0042] Example 3
[0043] This embodiment provides a polyurethane foam stabilizer, which is a polyether-grafted polysiloxane generated by reacting allyl polyether containing Diels-Alder bonds with low-hydrogen silicone oil under the catalysis of a platinum catalyst.
[0044] The allyl polyether containing Diels-Alder bonds is prepared through the following steps: Step S1: Mix furfuryl alcohol, sodium hydroxide, and water. Under nitrogen protection, heat to 90°C and add allyl glycidyl ether dropwise. After the addition is complete, keep the temperature constant and continue stirring for 3 hours. After the reaction is complete, add cation exchange resin to neutralize the reaction until neutral. Filter and distill the filtrate under reduced pressure to remove water and unreacted substances. Cool to room temperature to obtain allyl-furfuryl ether. The molar ratio of furfuryl alcohol to allyl glycidyl ether is 1:1; the molar ratio of furfuryl alcohol, sodium hydroxide, and water is 2.5g:0.1g:10mL. Step S2: Allyl-furfuryl glycerol ether and polyfunctional maleimide were added to chloroform and stirred at 65°C for 20 h to obtain allyl polyether containing Diels-Alder bonds. The ratio of allyl-furfuryl glycerol ether to chloroform was 1 g: 10 mL.
[0045] The multifunctional maleimide is 4,4'-bismaleimide diphenylmethane. The mass ratio of allyl-furfuryl glycerol ether to 4,4'-bismaleimide diphenylmethane is 3.5:5.8.
[0046] The low-hydrogen silicone oil used is the same as in Example 1.
[0047] The preparation method of this polyurethane foam stabilizer includes the following steps: The above-mentioned allyl polyether containing Diels-Alder bonds was added to toluene. Under nitrogen protection, a platinum catalyst was added, the temperature was raised to 50°C, and the mixture was stirred for 60 min. Then, the above-mentioned low-hydrogen silicone oil was added. After the addition was complete, the temperature was set to 62°C, and the mixture was stirred for 30 h. After the reaction was completed, the toluene was removed by rotary evaporation to obtain a polyurethane foam stabilizer. The amount of platinum catalyst added was 30 ppm of the total mass of the allyl polyether containing Diels-Alder bonds and the low-hydrogen silicone oil. The mass ratio of the allyl polyether containing Diels-Alder bonds to the low-hydrogen silicone oil was 70:100.
[0048] Example 4
[0049] This embodiment provides a polyurethane foam stabilizer, which is a polyether-grafted polysiloxane generated by reacting allyl polyether containing Diels-Alder bonds with low-hydrogen silicone oil under the catalysis of a platinum catalyst.
[0050] The allyl polyether containing Diels-Alder bonds is prepared through the following steps: Step S1: Mix furfuryl alcohol, sodium hydroxide, and water. Under nitrogen protection, heat to 85°C and add allyl glycidyl ether dropwise. After the addition is complete, keep the temperature constant and continue stirring for 3 hours. After the reaction is complete, add cation exchange resin to neutralize the reaction until neutral. Filter and distill the filtrate under reduced pressure to remove water and unreacted substances. Cool to room temperature to obtain allyl-furfuryl ether. The molar ratio of furfuryl alcohol to allyl glycidyl ether is 1:1; the molar ratio of furfuryl alcohol, sodium hydroxide, and water is 2.5g:0.1g:10mL. Step S2: Allyl-furfuryl glycerol ether and polyfunctional maleimide were added to chloroform and stirred at 65°C for 20 h to obtain allyl polyether containing Diels-Alder bonds. The ratio of allyl-furfuryl glycerol ether to chloroform was 1 g: 15 mL.
[0051] The multifunctional maleimide is tris(2-maleimide ethyl)amine. The mass ratio of allyl-furfuryl glycerol ether to tris(2-maleimide ethyl)amine is 3.5:3.8.
[0052] The low-hydrogen silicone oil is the same as in Example 1.
[0053] The preparation method of this polyurethane foam stabilizer includes the following steps: The above-mentioned allyl polyether containing Diels-Alder bonds was added to toluene. Under nitrogen protection, a platinum catalyst was added, the temperature was raised to 50°C, and the mixture was stirred for 60 min. Then, the above-mentioned low-hydrogen silicone oil was added. After the addition was complete, the temperature was set to 65°C, and the mixture was stirred for 30 h. After the reaction was completed, the toluene was removed by rotary evaporation to obtain a polyurethane foam stabilizer. The amount of platinum catalyst added was 30 ppm of the total mass of the allyl polyether containing Diels-Alder bonds and the low-hydrogen silicone oil. The mass ratio of the allyl polyether containing Diels-Alder bonds to the low-hydrogen silicone oil was 60:100.
[0054] Example 5
[0055] This embodiment provides a polyurethane foam stabilizer, which is a polyether-grafted polysiloxane generated by reacting an allyl polyether containing Diels-Alder bonds with a low-hydrogen silicone oil under the catalysis of a platinum catalyst. The difference between this embodiment and Example 1 lies in the low-hydrogen silicone oil, which is prepared through the following steps: High-hydrogen-content silicone oil, octamethylcyclotetrasiloxane, hexamethyldisiloxane, and concentrated sulfuric acid were mixed and reacted at 50°C for 7 hours. After the reaction was completed, water was added for two separate washings to remove the acidic water. Sodium bicarbonate powder was slowly added, and the acid was neutralized at 40-50°C (until pH paper showed neutrality). The mixture was filtered to remove insoluble sodium bicarbonate and sodium sulfate, and washed again with water. After washing, the mixture was distilled under vacuum at 120°C to remove low-boiling-point substances, and finally filtered to obtain low-hydrogen-content silicone oil. The high-hydrogen-content silicone oil had a mass fraction of 1.6%, and the mass ratio of high-hydrogen-content silicone oil, octamethylcyclotetrasiloxane, hexamethyldisiloxane, and concentrated sulfuric acid was 30:170:30:1. The low-hydrogen-content silicone oil had a hydrogen mass fraction of 0.2% and a viscosity of 24 mPa·s.
[0056] The remaining raw materials and preparation process are the same as in Example 5.
[0057] Example 6
[0058] This embodiment provides a polyurethane foam stabilizer, which is a polyether-grafted polysiloxane generated by reacting an allyl polyether containing Diels-Alder bonds with a low-hydrogen silicone oil under the catalysis of a platinum catalyst. The difference between this embodiment and Example 1 lies in the low-hydrogen silicone oil, which is prepared through the following steps: High-hydrogen-content silicone oil, octamethylcyclotetrasiloxane, hexamethyldisiloxane, and concentrated sulfuric acid were mixed and reacted at 5°C for 7 hours. After the reaction was completed, water was added for two separate washings to remove the acidic water. Sodium bicarbonate powder was slowly added, and the acid was neutralized at 40-50°C (until pH paper showed neutrality). The mixture was filtered to remove insoluble sodium bicarbonate and sodium sulfate, and washed again with water. After washing, the mixture was distilled under vacuum at 120°C to remove low-boiling-point substances, and finally filtered to obtain low-hydrogen-content silicone oil. The high-hydrogen-content silicone oil had a mass fraction of 1.6%, and the mass ratio of high-hydrogen-content silicone oil, octamethylcyclotetrasiloxane, hexamethyldisiloxane, and concentrated sulfuric acid was 30:170:10:1. The low-hydrogen-content silicone oil had a hydrogen mass fraction of 0.2% and a viscosity of 75 mPa·s.
[0059] The remaining raw materials and preparation process are the same as in Example 5.
[0060] Example 7
[0061] This embodiment provides a polyurethane foam stabilizer, the preparation method of which includes the following steps: Allyl polyether containing Diels-Alder bonds (same as in Example 1) was added to toluene. Under nitrogen protection, a platinum catalyst was added, the temperature was raised to 50°C, and the mixture was stirred for 50 min. Then, the above-mentioned low-hydrogen silicone oil (same as in Example 1) was added. After the addition was complete, the temperature was set to 60°C, and the mixture was stirred for 24 h. After the reaction was completed, the toluene was removed by rotary evaporation to obtain a polyurethane foam stabilizer. The amount of platinum catalyst added was 40 ppm of the total mass of the allyl polyether containing Diels-Alder bonds and the low-hydrogen silicone oil. The mass ratio of the allyl polyether containing Diels-Alder bonds to the low-hydrogen silicone oil was 65:100.
[0062] Example 8
[0063] This embodiment provides a polyurethane foam stabilizer, the preparation method of which includes the following steps: Allyl polyether containing Diels-Alder bonds (same as in Example 1) was added to toluene. Under nitrogen protection, a platinum catalyst was added, the temperature was raised to 52°C, and the mixture was stirred for 30 min. Then, the above-mentioned low-hydrogen silicone oil (same as in Example 1) was added. After the addition was complete, the temperature was set to 70°C, and the mixture was stirred for 24 h. After the reaction was completed, the toluene was removed by rotary evaporation to obtain a polyurethane foam stabilizer. The amount of platinum catalyst added was 35 ppm of the total mass of the allyl polyether containing Diels-Alder bonds and the low-hydrogen silicone oil. The mass ratio of the allyl polyether containing Diels-Alder bonds to the low-hydrogen silicone oil was 65:100.
[0064] Comparative Example 1
[0065] Compared to Example 1, this comparative example replaces the allyl polyether containing Diels-Alder bonds with allyl polyether (F-6), with a molecular weight of 1200, hydroxyl value of 45±8 mgKOH / g, and acid value of 0.3 mg≤KOH / g. The polyether is grafted onto polysiloxane and reacted with low-hydrogen silicone oil under a platinum catalyst. The preparation method of this polyurethane foam stabilizer includes the following steps: Allyl polyether (F-6) was added to toluene. Under nitrogen protection, a platinum catalyst was added, the temperature was raised to 50°C, and the mixture was stirred for 60 min. Then, the aforementioned low-hydrogen silicone oil was added. After the addition was complete, the temperature was set to 62°C, and the mixture was stirred for 30 h. After the reaction was completed, toluene was removed by rotary evaporation to obtain a polyurethane foam stabilizer. The amount of platinum catalyst added was 30 ppm of the total mass of allyl polyether (F-6) and low-hydrogen silicone oil. The mass ratio of allyl polyether (F-6) to low-hydrogen silicone oil was 240:100.
[0066] The remaining raw materials and preparation process are the same as in Example 1.
[0067] Comparative Example 2
[0068] Commercially available foam leveling agent: Silicone oil GSYPU G-580 polyurethane flexible foam leveling agent.
[0069] Comparative Example 3
[0070] Commercially available foam leveler: OFX-5043 polyether modified silicone oil.
[0071] Test case
[0072] The foaming agents prepared in Examples 1-8 and Comparative Examples 1-3 were tested; test samples were prepared: Add polyether polyol (hydroxyl value 56), distilled water, foam stabilizer, tertiary amine catalyst, and stannous octoate to a three-necked flask in a mass ratio of 100:4:1:0.2:0.4. Stir at high speed for 1 minute, add dichloromethane (8% of the polyether polyol mass), stir for 30 seconds, add TDI (46% of the polyether polyol mass), stir for another 10 seconds, and quickly pour into a mold. After the foam has stabilized for 1 hour, conduct the test. Compression set was tested according to Method A of GB / T 6669—2008; Surface defect test: After foaming with the above formula in a stainless steel mold with fixed dimensions of 60cm x 40cm x 20cm, count the number of surface defects with diameters exceeding 2cm x 2cm on each of the six sides of the foam, and set up six parallel groups to take the average value.
[0073] The results are shown in Table 1: Table 1
[0074] As shown in Table 1, the number of surface defects in Examples 1-8 of this invention is lower than that of commercially available products. A comparison with Examples 1 and Comparative Examples 1-3 reveals that the Diels-Alder bonds introduced in these examples can undergo reversible breakage and recombination at the high temperatures (typically 110°C-140°C) generated during polyurethane foaming. This characteristic enables the foam stabilizer and its stable foam system to possess a certain degree of in-situ self-healing ability during the foaming process. When microscopic defects occur in the cell walls due to stress or other reasons, this dynamic network can repair them through bond recombination, effectively inhibiting defect expansion and significantly improving the overall stability of the foam during complex nucleation, growth, and curing stages, thus significantly reducing the risk of foam collapse. In Comparative Example 1, conventional allyl polyether was used, which does not possess the above-mentioned effects, resulting in a relatively poor foam stabilization effect. The ability to promptly repair microscopic defects in the cell walls promotes the formation of a more complete and uniform three-dimensional cell network, helping to reduce defects such as cell merging and rupture, and forming a more complete foam skeleton. This type of skeleton has a stronger elastic recovery ability after compression deformation, thereby effectively reducing the compression set rate and improving the durability and shape retention of the foam.
[0075] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0076] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A polyurethane foam stabilizer, characterized in that, The polyurethane foam stabilizer is a polyether-grafted polysiloxane generated by reacting allyl polyether containing Diels-Alder bonds with low-hydrogen silicone oil under the catalysis of a platinum catalyst.
2. The polyurethane foam stabilizer according to claim 1, characterized in that, Allyl polyethers containing Diels-Alder bonds are prepared by the Diels-Alder reaction using allyl-furfuryl glycerol ether and multifunctional maleimide as reactants to obtain allyl polyethers containing Diels-Alder bonds with double bonds.
3. The polyurethane foam stabilizer according to claim 2, characterized in that, The allyl polyether containing Diels-Alder bonds is prepared by the following steps: Step S1: Mix furfuryl alcohol, sodium hydroxide and water, heat to 85-90℃ under nitrogen protection, add allyl glycidyl ether dropwise, keep the temperature constant after addition, and continue stirring for 3-4 hours to obtain allyl-furfuryl ether. Step S2: Allyl-furfuryl glycerol ether and polyfunctional maleimide are added to chloroform and stirred at 60-70℃ for 12-24 h to obtain allyl polyether containing Diels-Alder bonds.
4. The polyurethane foam stabilizer according to claim 3, characterized in that, The multifunctional maleimide is at least one of 4,4'-bismaleimide diphenylmethane and tris(2-maleimide ethyl)amine.
5. A polyurethane foam stabilizer according to claim 4, characterized in that, The mass ratio of allyl-furfuryl glycerol ether to polyfunctional maleimide is 3.5:3.8-7.
6. The polyurethane foam stabilizer according to claim 4, characterized in that, The mass ratio of allyl-furfuryl glycerol ether to 4,4'-bismaleimide diphenylmethane is 3.5:5.8-6.
7. A polyurethane foam stabilizer according to claim 4, characterized in that, The mass ratio of allyl-furfuryl glycerol ether to tris(2-maleimide ethyl)amine is 3.5:3.8-4.
8. The polyurethane foam stabilizer according to claim 1, characterized in that, The hydrogen content of the low-hydrogen silicone oil is 0.1%–0.3% by mass, and the viscosity is 20–100 mPa·s; the mass ratio of allyl polyether containing Diels-Alder bonds to the low-hydrogen silicone oil is 60–70:
100.
9. A method for preparing a polyurethane foam stabilizer, used to prepare the polyurethane foam stabilizer according to any one of claims 1-8, characterized in that, Includes the following steps: Allyl polyether containing Diels-Alder bonds is added to an organic solvent. Under nitrogen protection, a platinum catalyst is added, the temperature is raised to 50-52℃, and the mixture is stirred for 30-60 minutes. Then, low-hydrogen silicone oil is added. After the addition is complete, the temperature is set to 60-70℃, and the mixture is stirred for 24-36 hours. After the reaction is complete, toluene is removed by rotary evaporation to obtain a polyurethane foam stabilizer.
10. A method for preparing a polyurethane foam stabilizer according to claim 9, characterized in that, The amount of platinum catalyst added is 30-40 ppm of the total mass of allyl polyether containing Diels-Alder bonds and low-hydrogen silicone oil; the organic solvent is toluene.