Foaming agent and preparation method thereof
By using low-boiling-point fluorinated olefins and auxiliary foaming agents with specific compositions, the problems of ozone layer depletion and foam defects caused by hydrochlorofluorocarbons were solved, thereby improving the stability and mechanical strength of polyurethane foam.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-23
- Publication Date
- 2026-04-14
AI Technical Summary
Existing polyurethane foam blowing agents containing hydrochlorofluorocarbons (HCFCs) contribute to ozone layer depletion and the greenhouse effect. Furthermore, they are prone to causing foam defects such as bubble collapse, macropore formation, and uneven cell distribution during the production process, which reduces mechanical strength.
Low-boiling-point fluorinated olefins are used as the main foaming agent, supplemented by auxiliary foaming agents composed of octameryl polysilsesquioxane, fluorinated acrylate, polyethylene glycol monoacrylate, vinyl silicone oil and styrene, etc. The foaming agent is prepared through a specific molar ratio and ultraviolet radiation reaction to form stable and uniform foam pores, thereby enhancing the strength and toughness of the foam.
It avoids ozone layer depletion, improves the mechanical strength and stability of foam, prevents foam collapse and macropore formation, and achieves uniform distribution of foam cells.
Smart Images
Figure SMS_1 
Figure SMS_2
Abstract
Description
Technical Field
[0001] This invention relates to the field of foaming agent technology, and more particularly to a foaming agent and its preparation method. Background Technology
[0002] Polyurethane foam, as an important thermal insulation material, is widely used in refrigeration, pipeline insulation, and transportation due to its low thermal conductivity, light weight, and good dimensional stability. In the preparation of polyurethane foam, the foaming agent is a key component. It introduces air bubbles into the reaction system of polyether polyol and isocyanate through physical or chemical means to form a foam structure, directly affecting the foam's density, cell morphology, and final properties.
[0003] In existing technologies, polyurethane foam commonly uses hydrochlorofluorocarbons (HCFCs) as blowing agents. HCFCs are incorporated into a mixture of polyols and isocyanates, and the reaction is exothermic, causing them to vaporize and thus driving the foaming process. However, HCFC blowing agents not only face bans or restrictions due to ozone depletion and the strong greenhouse effect, but also easily cause foam defects during actual production, such as bubble collapse, macropore formation, and uneven cell distribution, reducing the mechanical strength of the foam. Summary of the Invention
[0004] To improve the foam stabilizing effect of foaming agents, this application provides a foaming agent and its preparation method.
[0005] Firstly, this application provides a foaming agent that adopts the following technical solution: A foaming agent comprising the following raw materials in parts by weight: 25-50 parts of main foaming agent, 10-15 parts of auxiliary foaming agent; The main blowing agent is a fluorinated olefin, and the auxiliary blowing agent includes octameryl polysilsesquioxane, fluorinated acrylate, polyethylene glycol monoacrylate, vinyl silicone oil, monocyclic olefin, styrene, and an initiator in a molar ratio of 1:(0.5-1):(2-3):(1-1.5):(2-3):(0.8-1.2):(0.2-0.4).
[0006] By adopting the above technical solution, this application uses low-boiling-point fluoroolefins as the main blowing agent to replace hydrochlorofluorocarbons in the prior art, which can avoid the banning or restriction problems caused by ozone depletion and strong greenhouse effect, and achieve zero ozone destruction.
[0007] The blowing agent in this application is dissolved in the polymer matrix. When the thermodynamic equilibrium of the system is broken, the fluoroolefin escapes from the polymer solution, forming the initial microbubble nuclei. It continues to vaporize, diffuse and enter the bubble nuclei from the polymer phase, causing the bubbles to expand rapidly. At the same time, the polymer matrix itself undergoes a chemical reaction (such as the polymerization reaction of isocyanate and polyol in polyurethane), and the viscosity of the system increases. Under the action of the auxiliary blowing agent, the expanded bubble structure is finally fixed, forming stable and uniform foam pores.
[0008] Among them, the octamercaptopolysilsesquioxane auxiliary foaming agent has a unique cage-like structure, which can form a network structure in the foam system, enhance the strength and toughness of the foam liquid film, reduce liquid film rupture, and play a role in stabilizing the foam. At the same time, using octamercaptopolysilsesquioxane as a crosslinking point, the grafted fluorinated acrylate and vinyl silicone oil synergistically reduce the viscosity of the system and impart a certain degree of hydrophobicity to the system. In addition, the reduction in viscosity can generate more bubble nuclei, making the foam have a finer and denser cell structure, while the silicon-oxygen bond structure gives the system a certain degree of high and low temperature resistance. Polyethylene glycol monoacrylate contains hydrophilic polyethylene glycol segments, which can increase the hydrophilicity of the system, and its flexible chain structure helps to regulate the viscosity of the system, giving it good flowability. Monocyclic olefins and styrene have rigid structures, which can enhance the cohesive energy of the system and regulate the viscosity of the system to a certain extent, so that the viscosity of the system is not too thin. In combination with other components, they can regulate the hydrophilic and lipophilic balance of the system. Amphiphilic auxiliary foaming agents, possessing both hydrophilic and oleophilic properties, can stably exist at the bubble wall interface before foam formation and curing, providing uniform interfacial tension and thus stabilizing the bubbles. When the foaming agent of this application is used to prepare polyurethane foam, problems such as bubble collapse, macropore formation, and uneven cell distribution can be avoided, thereby improving the mechanical strength of the foam.
[0009] Preferably, the preparation method of the auxiliary foaming agent includes the following steps: Octadecyl polysilsesquioxane, fluorinated acrylate, polyethylene glycol monoacrylate, vinyl silicone oil, monocyclic olefin, and styrene were dissolved in an organic solvent. An initiator was added, and the mixture was stirred until homogeneous. The reaction was carried out under ultraviolet radiation at room temperature. After the reaction was completed, the solid product was obtained by filtration and washing. The solid product was washed several times with methanol and then dried under vacuum to obtain the auxiliary foaming agent.
[0010] By adopting the above technical solution, using a specific molar ratio of octameryl polysilsesquioxane, fluorinated acrylate, polyethylene glycol monoacrylate, vinyl silicone oil, monocyclic olefin, styrene, and initiator as auxiliary foaming agents, and by dissolving each raw material in an organic solvent, adding the initiator and stirring evenly, followed by ultraviolet radiation reaction, filtration and washing, multiple washing with methanol, and vacuum drying, the generation of foam defects in actual production can be reduced and the mechanical strength of the foam can be improved.
[0011] Preferably, the fluorinated acrylate includes one or more of trifluoroethyl methacrylate, octafluoropentyl acrylate, and hexafluorobutyl acrylate.
[0012] By adopting the above technical solution, the fluorinated acrylate molecule contains fluorine groups, which have low surface energy. During the foaming process, the low surface energy enables the fluorinated acrylate to effectively reduce the surface tension of the system, which helps to form and stabilize bubbles.
[0013] Preferably, the monocyclic olefin includes one or both of cyclohexene and cyclopentene.
[0014] By adopting the above technical solution, monocyclic olefins are grafted onto the side chains of octamercaptopolysilsesquioxane under the action of an initiator, which regulates the formation and growth of cells, making the cells more uniform and dense, avoiding problems such as cell collapse, macropore formation and uneven cell distribution, thereby improving the mechanical strength of polyurethane foam.
[0015] Preferably, the vinyl silicone oil includes one of terminal vinyl polydimethylsiloxane and terminal vinyl polymethylvinylsiloxane.
[0016] Preferably, the vinyl silicone oil is selected from vinyl-terminated polydimethylsiloxane.
[0017] By adopting the above technical solution, the vinyl silicone oil contains Si-OR bonds. When these bonds are grafted onto the side chain of octamercaptopolysilsesquioxane, they work synergistically with the Si-O-Si framework to reduce the surface tension of the system, thereby better encapsulating and stabilizing bubbles, reducing the occurrence of bubble collapse, and making the cell distribution more uniform.
[0018] Preferably, the initiator includes one or two of benzoin dimethyl ether and 2-methyl-1-(4-(methylthio)phenyl-2-(4-morpholinyl)-1-propanone.
[0019] Preferably, the fluoroolefin includes one or both of cis-1,1,1,4,4,4-hexafluoro-2-butene and trans-1,1,1,4,4,4-hexafluoro-2-butene.
[0020] By adopting the above technical solution, fluoroolefins, as physical foaming agents, generate bubbles through a liquid-gas phase change during the foaming process.
[0021] Secondly, this application provides a method for preparing a foaming agent, which adopts the following technical solution: A method for preparing a foaming agent includes the following steps: The main foaming agent and auxiliary foaming agent are put into a high-speed mixer and stirred until uniform to obtain the foaming agent.
[0022] Preferably, the stirring speed is 1400-1800 rpm and the stirring time is 5-10 min. By adopting the above technical solution, the main foaming agent and auxiliary foaming agent are put into a high-speed mixer and stirred evenly to prepare a foaming agent, which can ensure that the components are fully mixed and the performance of the foaming agent is stable.
[0023] This application has the following beneficial effects: This application uses low-boiling-point fluoroolefins as the main blowing agent, replacing hydrochlorofluorocarbons in the prior art, which can avoid the banning or restriction problems faced due to ozone depletion and strong greenhouse effect, and achieve zero ozone destruction.
[0024] The blowing agent in this application is dissolved in the polymer matrix. When the thermodynamic equilibrium of the system is broken, the fluoroolefin escapes from the polymer solution, forming the initial microbubble nuclei. It continues to vaporize, diffuse and enter the bubble nuclei from the polymer phase, causing the bubbles to expand rapidly. At the same time, the polymer matrix itself undergoes a chemical reaction (such as the polymerization reaction of isocyanate and polyol in polyurethane), and the viscosity of the system increases. Under the action of the auxiliary blowing agent, the expanded bubble structure is finally fixed, forming stable and uniform foam pores.
[0025] Among them, the octamercaptopolysilsesquioxane auxiliary foaming agent has a unique cage-like structure, which can form a network structure in the foam system, enhance the strength and toughness of the foam liquid film, reduce liquid film rupture, and play a role in stabilizing the foam. At the same time, using octamercaptopolysilsesquioxane as a crosslinking point, the grafted fluorinated acrylate and vinyl silicone oil synergistically reduce the viscosity of the system and impart a certain degree of hydrophobicity to the system. In addition, the reduction in viscosity can generate more bubble nuclei, making the foam have a finer and denser cell structure, while the silicon-oxygen bond structure gives the system a certain degree of high and low temperature resistance. Polyethylene glycol monoacrylate contains hydrophilic polyethylene glycol segments, which can increase the hydrophilicity of the system, and its flexible chain structure helps to regulate the viscosity of the system, giving it good flowability. Monocyclic olefins and styrene have rigid structures, which can enhance the cohesive energy of the system and regulate the viscosity of the system to a certain extent, so that the viscosity of the system is not too thin. In combination with other components, they can regulate the hydrophilic and lipophilic balance of the system. Amphiphilic auxiliary foaming agents, possessing both hydrophilic and oleophilic properties, can stably exist at the bubble wall interface before foam formation and curing, providing uniform interfacial tension and thus stabilizing the bubbles. When the foaming agent of this application is used to prepare polyurethane foam, problems such as bubble collapse, macropore formation, and uneven cell distribution can be avoided, thereby improving the mechanical strength of the foam. Detailed Implementation
[0026] The present application will be further described in detail below with reference to the embodiments.
[0027] Preparation Example 1 The preparation method of the auxiliary foaming agent includes the following steps: Weigh out octamercaptopolysilsesquioxane, fluorinated acrylate, polyethylene glycol monoacrylate, vinyl silicone oil, monocyclic olefin, styrene, and initiator according to a molar ratio of 1:0.5:2:1:2:0.8:0.2; weigh out an organic solvent, specifically dichloromethane, at 20 times the total mass of octamercaptopolysilsesquioxane; select hexafluorobutyl acrylate as the fluorinated acrylate; choose a commercially available product, specifically from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.; select vinyl-terminated polydimethylsiloxane as the vinyl silicone oil, sourced from Hubei Xinyuhong Biomedical Technology Co., Ltd.; select cyclopentene as the monocyclic olefin; and select benzoin dimethyl ether as the initiator. Weigh out dichloromethane at 10 times the total mass of benzoin dimethyl ether and dissolve the benzoin dimethyl ether in dichloromethane to obtain the initiator solution.
[0028] Octadecyl polysilsesquioxane, hexafluorobutyl acrylate, polyethylene glycol monoacrylate, vinyl-terminated polydimethylsiloxane, cyclopentene, and styrene were dissolved in dichloromethane. An initiator solution was added, and the mixture was stirred until homogeneous. The mixture was then subjected to ultraviolet radiation at room temperature for 3 hours. After the reaction was completed, the solid product was obtained by filtration and washing. The solid product was then washed three times with methanol and dried under vacuum to obtain the auxiliary foaming agent.
[0029] Preparation Example 2 The preparation method of the auxiliary foaming agent includes the following steps: Weigh out octamercaptopolysilsesquioxane, fluorinated acrylate, polyethylene glycol monoacrylate, vinyl silicone oil, monocyclic olefin, styrene, and initiator according to a molar ratio of 1:0.8:2.5:1.2:2.5:1:0.3; weigh out an organic solvent, specifically dichloromethane, at 20 times the total mass of octamercaptopolysilsesquioxane; select trifluoroethyl methacrylate as the fluorinated acrylate; choose a commercially available product, specifically from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.; select vinyl-terminated polydimethylsiloxane as the vinyl silicone oil, sourced from Hubei Xinyuhong Biomedical Technology Co., Ltd.; select cyclohexene as the monocyclic olefin; and select benzoin dimethyl ether as the initiator. Weigh out dichloromethane at 10 times the total mass of benzoin dimethyl ether and dissolve the benzoin dimethyl ether in dichloromethane to obtain the initiator solution.
[0030] Octadecyl polysilsesquioxane, trifluoroethyl methacrylate, polyethylene glycol monoacrylate, vinyl-terminated polydimethylsiloxane, cyclohexene, and styrene were dissolved in dichloromethane. An initiator solution was added, and the mixture was stirred until homogeneous. The mixture was then subjected to ultraviolet radiation at room temperature for 4 hours. After the reaction was completed, the solid product was obtained by filtration and washing. The solid product was then washed three times with methanol and dried under vacuum to obtain the auxiliary foaming agent.
[0031] Preparation Example 3 Weigh out octameryl polysilsesquioxane, fluorinated acrylate, polyethylene glycol monoacrylate, vinyl silicone oil, monocyclic olefin, styrene, and initiator according to a molar ratio of 1:1:3:1.5:3:1.2:0.4; weigh out an organic solvent, specifically dichloromethane, at 20 times the total mass of the octameryl polysilsesquioxane; select octafluoropentyl acrylate; choose a commercially available product, specifically from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd.; and select vinyl silicone oil, specifically vinyl-terminated polydimethylsiloxane. The alkyl group, terminal vinyl polydimethylsiloxane, was sourced from Hubei Xinyuhong Biomedical Technology Co., Ltd.; the monocyclic olefin was cyclopentene; the initiator was 2-methyl-l-(4-(methylthio)phenyl-2-(4-morpholinyl)-1-propanone, and dichloromethane was weighed at 10 times the total mass of 2-methyl-l-(4-(methylthio)phenyl-2-(4-morpholinyl)-1-propanone, and the initiator solution was obtained by dissolving 2-methyl-l-(4-(methylthio)phenyl-2-(4-morpholinyl)-1-propanone in dichloromethane.
[0032] Octaptyl polysilsesquioxane, octafluoropentyl acrylate, polyethylene glycol monoacrylate, vinyl-terminated polydimethylsiloxane, cyclopentene, and styrene were dissolved in dichloromethane. An initiator solution was added, and the mixture was stirred until homogeneous. The mixture was then subjected to ultraviolet radiation at room temperature for 5 hours. After the reaction was completed, the solid product was obtained by filtration and washing. The solid product was then washed three times with methanol and dried under vacuum to obtain the auxiliary foaming agent.
[0033] Preparation Example 4 The difference between this preparation example and preparation example 2 is that the vinyl silicone oil is replaced with end-vinyl polymethyl vinyl siloxane.
[0034] Preparation Example 5 The difference between this preparation example and preparation example 2 is that the fluorinated acrylate is replaced with dodecafluoroheptyl methacrylate.
[0035] Comparative Preparation Example 1 The difference between this comparative preparation example and preparation example 2 is that the fluorinated acrylate was replaced by butyl acrylate in equal mass.
[0036] Comparative Preparation Example 2 The difference between this comparative preparation example and preparation example 2 is that the monocyclic olefin was replaced by an equal mass of cyclohexane.
[0037] Comparative preparation example 3 The difference between this comparative preparation example and preparation example 2 is that polyethylene glycol monoacrylate was not added.
[0038] Comparative preparation example 4 The difference between this comparative preparation example and preparation example 2 is that vinyl silicone oil was not added.
[0039] Comparative preparation example 5 The difference between this comparative preparation example and preparation example 2 is that styrene was not added.
[0040] Example 1 The preparation method of the foaming agent includes the following steps: The raw materials were weighed according to the following proportions: 25 parts of main foaming agent and 10 parts of auxiliary foaming agent. The auxiliary foaming agent was prepared by Preparation Example 1. The main foaming agent was selected as cis-1,1,1,4,4,4-hexafluoro-2-butene.
[0041] Add the main foaming agent and auxiliary foaming agent into a high-speed mixer and stir at 1400 rpm for 5 minutes until they are evenly mixed to obtain the foaming agent.
[0042] Example 2 The preparation method of the foaming agent includes the following steps: The raw materials were weighed according to the following proportions: 35 parts of main foaming agent and 12 parts of auxiliary foaming agent. The auxiliary foaming agent was prepared by Preparation Example 2. The main foaming agent was selected as cis-1,1,1,4,4,4-hexafluoro-2-butene.
[0043] The main foaming agent and auxiliary foaming agent are put into a high-speed mixer and stirred at 1600 rpm for 8 minutes until they are uniformly mixed to obtain the foaming agent.
[0044] Example 3 The preparation method of the foaming agent includes the following steps: The raw materials were weighed according to the following proportions: 50 parts of main foaming agent and 15 parts of auxiliary foaming agent. The auxiliary foaming agent was prepared by Preparation Example 3. The main foaming agent was trans-1,1,1,4,4,4-hexafluoro-2-butene.
[0045] Add the main foaming agent and auxiliary foaming agent into a high-speed mixer and stir at 1800 rpm for 10 minutes until they are evenly mixed to obtain the foaming agent.
[0046] Example 4 The difference between this embodiment and Example 2 is that the auxiliary foaming agent prepared in Example 4 is used.
[0047] Example 5 The difference between this embodiment and Example 2 is that the auxiliary foaming agent prepared in Example 5 is used.
[0048] Comparative Example 1 The method for preparing the foaming agent differs from that in Example 2 in that the auxiliary foaming agent prepared in Comparative Preparation Example 1 is used.
[0049] Comparative Example 2 The method for preparing the foaming agent differs from that in Example 2 in that the auxiliary foaming agent prepared in Comparative Preparation Example 2 is used.
[0050] Comparative Example 3 The method for preparing the foaming agent differs from that in Example 2 in that the auxiliary foaming agent prepared in Comparative Preparation Example 3 is used.
[0051] Comparative Example 4 The method for preparing the foaming agent differs from that in Example 2 in that the auxiliary foaming agent prepared in Comparative Preparation Example 4 is used.
[0052] Comparative Example 5 The method for preparing the foaming agent differs from that in Example 2 in that the auxiliary foaming agent prepared in Comparative Preparation Example 5 is used.
[0053] Comparative Example 6 The preparation method of the foaming agent differs from that in Example 2 in that the auxiliary foaming agent is replaced by an equal mass of cis-1,1,1,4,4,4-hexafluoro-2-butene. Performance testing
[0054] Sample preparation The following are some of the sources of raw materials: Polyether polyol: YD-8239G, industrial grade, hydroxyl value (395±15)mgKOH / g, Hebei Yadong Chemical Group Co., Ltd.; Polyether polyol: Sa-380, industrial grade, hydroxyl value (375±20) mgKOH / g, Shandong Lanxing Dongda Chemical Co., Ltd.; Polyether polyol: Sa-460, industrial grade, hydroxyl value (460±15)mgKOH / g, Shandong Lanxing Dongda Chemical Co., Ltd.; Polyester polyol: PS-3152, industrial grade, hydroxyl value (315±15)mgKOH / g, Stepan Chemical (Nanjing) Co., Ltd.; Polymer MDI: Polymer MDI 44V20L, Hubei Maidehao Biotechnology Co., Ltd.; Catalysts: PC-5, PC-8, Evonik Specialty Chemicals (Shanghai) Co., Ltd.
[0055] Table 1 Formulation of Rigid Polyurethane Foam
[0056] Note: The polyol combination is composed of YD-8239G, Sa-380, Sa-460 and PS-3152 in a mass ratio of 5:3:1:1; the catalyst is composed of PC-5 and PC-8 in a mass ratio of 2:5.
[0057] According to the rigid polyurethane foam formulation in Table 1, 20 kg of white material was prepared for each example and comparative example. The mixture was stirred evenly and allowed to stand at room temperature for 12 hours to defoam. The black and white materials were then separately placed into black and white material storage tanks, with the material temperature controlled at 20°C and the mixing head pressure at 12 MPa. At an ambient temperature of 25°C, the material was poured into a mold using an injection molding machine, with the mold temperature set to 45°C. After a full reaction of 15 minutes, the rigid polyurethane foam was removed from the mold and cured at room temperature for 48 hours to prepare samples for performance testing.
[0058] 1. Compression strength test: The test shall be conducted in accordance with GB / T 8813-2008 standard, and the sample size shall be 50 mm × 50 mm × 50 mm.
[0059] 2. Closed-cell rate: Tested according to GB / T 10799-2008, with sample size of 25 mm × 25 mm × 25 mm.
[0060] 3. Apparent density: Apparent density was tested according to GB / T 6343-2009, and the sample size was 50 mm × 50 mm × 50 mm.
[0061] Table 2
[0062] Based on the comparison between Examples 2 and 5 and the data in Table 2, it can be seen that: acrylates with high fluorine content and highly branched structure may have excessively low surface free energy, leading to a decreasing viscosity of the system. However, when the viscosity decreases to a certain extent, a defoaming effect may occur, causing bubbles to easily coalesce, rupture, and escape into open pores, resulting in problems such as large pores and open pores in the foam. In contrast, Example 2 of this application uses trifluoroethyl methacrylate with a low fluorine content and branched structure, which has moderate viscosity, good foam stability, and is not easily ruptured.
[0063] Based on the comparison between Example 2 and Comparative Example 1 and the data in Table 2, it can be seen that the auxiliary foaming agent in Comparative Example 1 lacks CF bonds, resulting in excessively high system viscosity. The miscibility between the foaming agent and other components is worse than in Example 2, which may lead to foam collapse and is not conducive to the formation of continuous and uniform foam.
[0064] Based on the comparison between Example 2 and Comparative Example 2, and the data in Table 2, it can be seen that during the preparation of the auxiliary foaming agent, the double bond in the monocyclic olefin undergoes a "thiolene" click reaction with -SH, thereby forming a cyclic structure in the auxiliary foaming agent molecule, which synergistically regulates the hydrophilicity and hydrophobicity of the foaming agent with other groups. However, the cyclohexane in Comparative Example 2 does not contain a double bond and cannot combine with -SH, leading to an imbalance between the hydrophilicity and hydrophobicity of the foaming agent, thus affecting the foaming effect.
[0065] Based on the comparison between Example 2 and Comparative Example 3 and the data in Table 2, it can be seen that the auxiliary foaming agent of Comparative Example 3 lacks polyethylene glycol segments in its molecular structure, that is, it lacks hydrophilic groups, which affects the miscibility between components, and the emulsification performance of the foaming agent is poor, thus affecting the mechanical strength of the foam material.
[0066] Based on the comparison between Example 2 and Comparative Example 4, and the data in Table 2, it can be seen that the Si-O-Si segments in octamercaptopolysilsesquioxane and the Si-O segments in terminal vinyl polydimethylsiloxane have a synergistic effect in reducing the surface tension of the system. However, since the auxiliary foaming agent in Comparative Example 4 lacks the Si-O segments in terminal vinyl polydimethylsiloxane, the balance between surface tension and foam uniformity is disrupted, affecting the emulsifying performance of the foaming agent and thus the cell structure.
[0067] Based on the comparison between Example 2 and Comparative Example 5 and the data in Table 2, it can be seen that the auxiliary foaming agent of Comparative Example 5 lacks a benzene ring structure in its molecular structure, resulting in a lower system viscosity than that of Example 2. The bubbles are prone to coalescence and rupture, causing the phenomenon that affects the mechanical strength of the foam material.
[0068] Based on the comparison between Example 2 and Comparative Example 6, and the data in Table 2, it can be seen that Comparative Example 6 lacks an auxiliary foaming agent, which makes the material prone to phenomena such as collapsed bubbles, large pores, and uneven pores during the foaming process.
[0069] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this specific embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.
Claims
1. A foaming agent, characterized in that, Including the following parts by weight of raw materials: 25-50 parts of main foaming agent, 10-15 parts of auxiliary foaming agent; The main blowing agent is a fluorinated olefin, and the auxiliary blowing agent includes octameryl polysilsesquioxane, fluorinated acrylate, polyethylene glycol monoacrylate, vinyl silicone oil, monocyclic olefin, styrene, and an initiator in a molar ratio of 1:(0.5-1):(2-3):(1-1.5):(2-3):(0.8-1.2):(0.2-0.4).
2. The foaming agent according to claim 1, characterized in that, The preparation method of the auxiliary foaming agent includes the following steps: Octadecyl polysilsesquioxane, fluorinated acrylate, polyethylene glycol monoacrylate, vinyl silicone oil, monocyclic olefin, and styrene were dissolved in an organic solvent. An initiator was added, and the mixture was stirred until homogeneous. The reaction was carried out under ultraviolet radiation at room temperature. After the reaction was completed, the solid product was obtained by filtration and washing. The solid product was washed several times with methanol and then dried under vacuum to obtain the auxiliary foaming agent.
3. The foaming agent according to claim 1, characterized in that, The fluorinated acrylates include one or more of trifluoroethyl methacrylate, octafluoropentyl acrylate, and hexafluorobutyl acrylate.
4. The foaming agent according to claim 1, characterized in that, The monocyclic olefins include one or both of cyclohexene and cyclopentene.
5. A foaming agent according to claim 1, characterized in that, The vinyl silicone oil includes one of terminal vinyl polydimethylsiloxane and terminal vinyl polymethylvinylsiloxane.
6. The foaming agent according to claim 1, characterized in that, The vinyl silicone oil is selected from vinyl-terminated polydimethylsiloxane.
7. A foaming agent according to claim 1, characterized in that, The initiator includes one or two of benzoin dimethyl ether and 2-methyl-1-(4-(methylthio)phenyl-2-(4-morpholino)-1-propanone.
8. A foaming agent according to claim 1, characterized in that, The fluoroolefins include one or both of cis-1,1,1,4,4,4-hexafluoro-2-butene and trans-1,1,1,4,4,4-hexafluoro-2-butene.
9. A method for preparing a foaming agent according to any one of claims 1-8, characterized in that, Includes the following steps: The main foaming agent and auxiliary foaming agent are put into a high-speed mixer and stirred until uniform to obtain the foaming agent.
10. A method for preparing a foaming agent according to claim 9, characterized in that, The stirring speed is 1400-1800 rpm, and the stirring time is 5-10 min.