Preparation method of low-thermal-conductivity foaming composition for low-density quick release system

Abstract

The invention relates to the technical field of foaming compositions, and particularly discloses a low-thermal-conductivity foaming composition for a low-density quick release system and a preparation method of the low-thermal-conductivity foaming composition. The invention relates to a low-thermal-conductivity foaming composition for a low-density quick-release system. The low-thermal-conductivity foaming composition is prepared from the following raw materials in parts by weight: 13-14 parts of cyclopentane, 130-140 parts of polymethylene polyphenyl isocyanate, 50-60 parts of polycarbonate diol, 25-30 parts of o-xylene ammonium ether, 1.6-1.8 parts of deionized water, 3-4 parts of an emulsifier and 7-10 parts of modified composite fibers. The low-thermal-conductivity foaming composition for the low-density and quick-release system has the advantages of high foam closed cell rate and low thermal conductivity coefficient.

Description

Technical Field

[0001] The present application relates to the technical field of foaming compositions, and more particularly, to a method for preparing a low thermal conductivity foaming composition for a low-density, quick-release system. Background Art

[0002] With increasingly stringent global environmental regulations, particularly the EU's planned ban on refrigerators containing fluorinated foaming agents, effective January 1, 2026, the automotive refrigerator industry faces significant technical challenges. Traditional automotive refrigerators commonly use fluorinated foaming agents. While these agents offer low thermal conductivity and excellent insulation performance, they are environmentally hazardous and may not meet future environmental regulations. Therefore, developing a fluorine-free, low-thermal-conductivity, and high-closed-cell foaming composition has become a key area of ​​technological innovation for the industry.

[0003] Due to their unique operating environment, car refrigerators place higher demands on the performance of foam materials. First, due to the location of their installation within the vehicle, the foam layer is typically thin while maintaining sufficient volume, placing higher demands on the thermal insulation performance of the foam material. Second, car refrigerators must withstand complex mechanical environments such as vibration and impact during use, requiring the foam material to possess excellent mechanical strength and durability. Furthermore, with consumers' increasing concern for environmental performance, the development of foam materials that comply with environmental regulations has become an inevitable trend in the industry.

[0004] Currently, industry solutions primarily focus on optimizing the cell density and closed-cell ratio of foam materials. Cell density directly impacts the thermal conductivity of the foam material: the finer the cells, the lower the thermal conductivity and the better the insulation performance. The closed-cell ratio determines the thermal insulation performance of the foam material. A high closed-cell ratio can effectively reduce heat loss and improve insulation. However, traditional foam materials have deficiencies in cell density and closed-cell ratio, resulting in high thermal conductivity that makes them difficult to meet the stringent insulation requirements of in-car refrigerators.

[0005] A Chinese patent application document with application publication number CN101962474A discloses an environmentally friendly, highly flame-retardant rigid polyurethane foam, its preparation method, and application. This invention is obtained by mixing and reacting polymer polyols, water, flame retardants, modified hollow microspheres, and polyisocyanates in the presence of a foam leveler and / or catalyst. The foam can be preferably used in the insulation of building exterior walls, pipelines, and refrigeration equipment.

[0006] The aforementioned document states that during actual processing, hollow microspheres are susceptible to rupture due to mechanical agitation or shear forces during foaming, resulting in uneven dispersion within the foam matrix. Furthermore, ruptured hollow microspheres lose the insulating benefits of their hollow structure, further reducing their overall insulation effectiveness, failing to achieve the desired effect and, consequently, diminishing the thermal insulation performance of the polyurethane foam. Summary of the Invention

[0007] In order to further reduce the thermal conductivity of a low thermal conductivity foaming composition used in a low-density quick-release system and thereby improve its thermal insulation effect, the present application provides a low thermal conductivity foaming composition for a low-density quick-release system and a preparation method thereof.

[0008] In the first aspect, the present application provides a low thermal conductivity foaming composition for a low-density quick-release system, which adopts the following technical solution: A low thermal conductivity foaming composition for a low-density quick-release system is prepared from the following raw materials in parts by weight: 13-14 parts of cyclopentane, 130-140 parts of polymethylene polyphenyl isocyanate, 50-60 parts of polycarbonate diol, 25-30 parts of o-xylene ammonium ether, 1.6-1.8 parts of deionized water, 3-4 parts of an emulsifier, and 7-10 parts of modified composite fibers; The preparation method of the modified composite fiber comprises the following steps: (1) Soak chitosan in an acetic acid aqueous solution, add triethylamine, let it stand, filter, wash, add a mixed solution of cyclopentyl methyl ether and triethylamine and stir evenly, then add fatty acid chloride, pour into methanol after the reaction is completed, filter, wash, and dry to obtain modified chitosan; (2) uniformly mixing the modified chitosan, thermoplastic polyurethane and dimethylacetamide to obtain a spinning solution; (3) The spinning solution is injected into a syringe for electrospinning, and the fibers obtained by spinning are soaked in deionized water. The soaked fibers are then taken out, washed, dried, and crushed to obtain modified composite fibers.

[0009] By adopting the above technical solution, the prepared modified composite fiber has good dispersibility in the foaming composition matrix and good compatibility with the foaming composition matrix, so that the foaming composition has good dimensional stability. At the same time, the presence of the modified composite fiber makes the foam closed cell rate higher during the foaming process, thereby making the foaming composition have good thermal insulation performance.

[0010] Preferably, the preparation method of the emulsifier comprises the following steps: S1: Mix dodecylphenol polyoxyethylene ether and sulfuric acid evenly, heat to 70-85°C, add epichlorohydrin, and react for 12-15 hours to obtain an intermediate; S2: Evenly mix triethylenetetramine and ethylene glycol, raise the temperature to 50-70°C, add the intermediate and dimethylchlorosilane, then raise the temperature to 85-95°C, and react for 4-6 hours to obtain an emulsifier.

[0011] By adopting this technical solution, the various components of the emulsifier are adsorbed at the gas-liquid interface, increasing surface activity, more effectively reducing surface tension, and promoting the formation and stability of bubbles. This also promotes the formation of more bubble nuclei and inhibits excessive bubble growth and merging, resulting in smaller and more uniform cells and improved foam density, uniformity, and stability.

[0012] Preferably, in step (1), the soaking treatment time is 1-3 hours.

[0013] Preferably, in step (1), the fatty acid chloride is any two of hexanoyl chloride, stearoyl chloride and lauroyl chloride.

[0014] Preferably, in step (2), the mass ratio of modified chitosan, thermal polyurethane and dimethylacetamide is 1:(1.5-2):(8-9.5).

[0015] Preferably, in step (3), the process parameters of electrospinning are: voltage 20-30 kV, receiving distance 15-20 cm, feed rate 3-5 mL / h; the average length of the modified composite fiber after crushing is 0.8-1 cm.

[0016] Preferably, the soaking treatment in step (3) is carried out at a temperature of 40-50° C. and for a time of 0.5-1 h.

[0017] By soaking the fibers prepared by spinning, the long aliphatic chains on the fiber surface are exposed. During the formation of the foaming composition, they are inserted between the matrix molecular chains, increasing the flexibility and spacing of the molecular chains, reducing the effect of resistance on bubble formation, and thereby improving the pore density.

[0018] Preferably, the addition rate of epichlorohydrin in step S1 is 0.13-0.2 g / min.

[0019] Preferably, in step S2, the mass ratio of triethylenetetramine, ethylene glycol, intermediate and dimethylmonochlorosilane is 1:(1.7-2):(2-2.5):(0.3-0.5).

[0020] In a second aspect, the present application provides a method for preparing a low thermal conductivity foaming composition for a low-density quick-release system, comprising the following steps: a: Mix the modified composite fiber and deionized water, disperse them by ultrasonication, add polycarbonate diol, o-xylidine ether and emulsifier, mix and stir for 40-60 minutes, then add cyclopentane and mix evenly to obtain a composite polyether material; b: Mixing the combined polyether material and polymethylene polyphenyl isocyanate, pouring the mixture into a mold, foaming and molding, and demolding to obtain a low thermal conductivity foaming composition for a low-density quick-release system.

[0021] Preferably, the frequency of the ultrasonic dispersion is 30-60 kHz, and the time is 25-40 min.

[0022] In summary, this application has the following beneficial effects: 1. The polyurethane in the modified composite fiber has good compatibility in the foaming composition and is tightly combined with the foaming composition matrix, providing an additional support structure for the foaming composition, making the overall structure more stable and improving the ability of the foaming composition to resist external damage. At the same time, the addition of the modified composite fiber can limit the expansion and contraction of the polyurethane foam during the foaming process, making its size more stable.

[0023] 2. The modified chitosan is swellable in deionized water. The modified composite fiber obtained by immersion treatment has the long aliphatic chains on the surface modified chitosan stretched out. During the formation of the foaming composition, the long aliphatic chains are inserted between the molecular chains of the matrix, increasing the flexibility and spacing of the molecular chains. The flexible chain segments can undergo reversible deformation during the foaming expansion stage, avoiding the rupture of the bubble wall caused by stress concentration of the rigid chain, thereby reducing the rupture of the bubble cells and the fineness of the bubble cells. At the same time, the cross-linked network is formed to limit the diffusion of gas in the bubble cells and improve the closed cell rate.

[0024] 3. During the foaming process, the modified composite fiber acts as a heterogeneous nucleation site, promoting cell formation, increasing the number of cells and reducing their size. Furthermore, due to the good compatibility of the modified composite fiber with the foaming matrix, the modified composite fiber can be evenly dispersed in the system, thereby affecting the distribution of the foaming gas and making the cells more uniform throughout the foam, avoiding performance differences caused by localized excessive or insufficient cells. At the same time, the fiber tightly bonds with the pore walls of the closed cells, enhancing their structural strength and enabling them to better withstand external pressure and resist rupture, thereby reducing the thermal conductivity of the foamed composition and improving its thermal insulation properties. DETAILED DESCRIPTION

[0025] The present application is further described in detail below with reference to the embodiments.

[0026] Unless otherwise specified, the raw materials used in the examples and comparative examples of the present application are all commercially available.

[0027] Example 1 The low thermal conductivity foaming composition for the low-density quick-release system of this embodiment is made from the following raw materials: 14g of cyclopentane, 130g of polymethylene polyphenyl isocyanate, 50g of polycarbonate diol, 30g of o-xylene ammonium ether, 1.6g of deionized water, 3g of coconut diethanolamide, and 7g of modified composite fiber.

[0028] And it is prepared by the following preparation steps: 8g chitosan was soaked in 50g of 1% acetic acid aqueous solution by mass percentage for 1h, and then triethylamine was added to adjust the pH to 8, and the mixture was allowed to stand for 5min, filtered, washed, and 50g of cyclopentyl methyl ether and 15g of triethylamine were added and stirred evenly. The temperature was adjusted to 9°C, and then 1g of lauroyl chloride was added, the temperature was raised to 40°C, and the mixture was reacted for 6h. The mixture was cooled to room temperature, and then 0.5g of hexanoyl chloride was added and the mixture was reacted for 5h. After the reaction, the mixture was poured into 500mL of methanol, filtered, washed, and dried to obtain modified chitosan. 10g Modified chitosan, 15g of thermoplastic polyurethane and 80g of dimethylacetamide were mixed evenly to obtain a spinning solution, which was injected into a syringe for electrospinning. The electrospinning voltage was 20kV, the feed rate was 3mL / h, and the receiving distance was 15cm. The fibers obtained by spinning were soaked in deionized water at a temperature of 40°C for 1h. The soaked fibers were then taken out, washed, dried, and crushed into a state with a length of 0.8cm to obtain modified composite fibers.

[0029] 7 g of modified composite fiber and 1.6 g of deionized water were mixed, and ultrasonically dispersed at a frequency of 30 kHz for 40 minutes. 50 g of polycarbonate diol, 30 g of o-xylidine ether and 3 g of emulsifier were added and stirred for 40 minutes. 14 g of cyclopentane was then added and mixed evenly to obtain a combined polyether material. The combined polyether material and 130 g of polymethylene polyphenyl isocyanate were then put into a high-pressure foaming machine and mixed evenly. The mixture was poured into a mold, foamed and molded, and demolded to obtain a low thermal conductivity foaming composition for a low-density quick-release system.

[0030] Example 2 The low thermal conductivity foaming composition for the low-density quick-release system of this embodiment is made from the following raw materials: 13g of cyclopentane, 140g of polymethylene polyphenyl isocyanate, 60g of polycarbonate diol, 25g of o-xylene ammonium ether, 1.8g of deionized water, 4g of emulsifier, and 10g of modified composite fiber.

[0031] And it is prepared by the following preparation steps: 12g chitosan was soaked in 80g of 1% acetic acid aqueous solution by mass for 3h, and then triethylamine was added to adjust the pH to 9, and the mixture was allowed to stand for 10min, filtered, washed, and then 90g of cyclopentyl methyl ether and 22g of triethylamine were added and stirred evenly. The temperature was adjusted to 0℃, and then 1.2g of stearyl chloride was added, the temperature was raised to 45℃, and the mixture was reacted for 6h. The mixture was cooled to room temperature, and then 0.5g of hexanoyl chloride was added and the mixture was reacted for 4h. After the reaction, the mixture was poured into 500mL of methanol, filtered, washed, and dried to obtain modified chitosan. 0g modified chitosan, 20g thermoplastic polyurethane and 95g dimethylacetamide were mixed evenly to obtain a spinning solution, which was injected into a syringe for electrospinning. The electrospinning voltage was 30kV, the feed rate was 5mL / h, and the receiving distance was 20cm. The fibers obtained by spinning were soaked in deionized water at a temperature of 50°C for 0.5h. The soaked fibers were then taken out, washed, dried, and crushed into a state with a length of 1cm to obtain modified composite fibers.

[0032] Mix 65g of dodecylphenol polyoxyethylene ether and 0.4g of sulfuric acid, heat to 70°C, add 7.5g of epichlorohydrin at a rate of 0.13g / min, and react for 12h to obtain an intermediate; then mix 10g of triethylenetetramine and 20g of ethylene glycol, heat to 50°C, add 25g of the intermediate and 5g of dimethylmonochlorosilane, then heat to 85°C and react for 6h to obtain an emulsifier.

[0033] 10 g of modified composite fiber and 1.8 g of deionized water were mixed, and ultrasonically dispersed at a frequency of 60 kHz for 25 minutes. 60 g of polycarbonate diol, 25 g of o-xylidine ether, and 4 g of emulsifier were added and stirred for 60 minutes. 13 g of cyclopentane was then added and mixed evenly to obtain a combined polyether material. The combined polyether material and 140 g of polymethylene polyphenyl isocyanate were then mixed evenly, poured into a mold, foamed, and demolded to obtain a low thermal conductivity foaming composition for a low-density quick-release system.

[0034] Example 3 The low thermal conductivity foaming composition for the low-density quick-release system of this embodiment is made from the following raw materials: 13.7 g of cyclopentane, 135 g of polymethylene polyphenyl isocyanate, 52 g of polycarbonate diol, 26 g of o-xylene ammonium ether, 1.7 g of deionized water, 3.2 g of emulsifier, and 8 g of modified composite fiber.

[0035] And it is prepared by the following preparation steps: 10 g of chitosan was soaked in 70 g of 1% acetic acid aqueous solution for 2 h, and triethylamine was added to adjust the pH to 8.5. The mixture was allowed to stand for 5 min, filtered, washed, and 60 g of cyclopentyl methyl ether and 20 g of triethylamine were added and stirred evenly. The temperature was adjusted to 0 ° C. 1.1 g of lauroyl chloride was added, the temperature was raised to 43 ° C. and the reaction was continued for 6.5 h. The mixture was cooled to room temperature, and 0.3 g of stearoyl chloride was added and the reaction was continued for 5 h. After the reaction, the mixture was poured into 500 mL of methanol, filtered, washed, and dried to obtain modified chitosan. 10g modified chitosan, 17g thermoplastic polyurethane and 85g dimethylacetamide were mixed evenly to obtain a spinning solution, which was injected into a syringe for electrospinning. The electrospinning voltage was 25kV, the feed rate was 4mL / h, and the receiving distance was 17cm. The fibers obtained by spinning were soaked in deionized water at a temperature of 45°C for 0.6h. The soaked fibers were then taken out, washed, dried, and crushed to a length of 0.9cm to obtain modified composite fibers.

[0036] Mix 60g of dodecylphenol polyoxyethylene ether and 0.4g of sulfuric acid, heat to 85°C, add 8g of epichlorohydrin at a rate of 0.15g / min, and react for 15h to obtain an intermediate; then mix 10g of triethylenetetramine and 17g of ethylene glycol, heat to 70°C, add 20g of the intermediate and 3g of dimethylchlorosilane, then heat to 95°C and react for 4h to obtain an emulsifier.

[0037] 8 g of modified composite fiber and 1.7 g of deionized water were mixed, and ultrasonically dispersed at a frequency of 40 kHz for 30 minutes. 52 g of polycarbonate diol, 26 g of o-xylidine ether, and 3.2 g of emulsifier were added and stirred for 50 minutes. 13.7 g of cyclopentane was then added and mixed evenly to obtain a combined polyether material. The combined polyether material and 135 g of polymethylene polyphenyl isocyanate were then put into a high-pressure foaming machine and mixed evenly. The mixture was poured into a mold, foamed, and demolded to obtain a low thermal conductivity foaming composition for a low-density quick-release system.

[0038] Example 4 The low thermal conductivity foaming composition for the low-density quick-release system of this embodiment is made from the following raw materials: 13.5g of cyclopentane, 138g of polymethylene polyphenyl isocyanate, 57g of polycarbonate diol, 27g of o-xylene ammonium ether, 1.6g of deionized water, 3.5g of emulsifier, and 9g of modified composite fiber.

[0039] And it is prepared by the following preparation steps: 8g of chitosan was soaked in 50g of 1% acetic acid aqueous solution by mass for 2h, and then triethylamine was added to adjust the pH to 8, and the mixture was allowed to stand for 5min, filtered, washed, and 60g of cyclopentyl methyl ether and 15g of triethylamine were added and stirred evenly. The temperature was adjusted to 0℃, and then 1g of lauroyl chloride was added, the temperature was raised to 42℃, and the reaction was carried out for 6h. The mixture was cooled to room temperature, and then 0.5g of hexanoyl chloride was added and the reaction was carried out for 4h. After the reaction, the mixture was poured into 500mL of methanol, filtered, washed, and dried to obtain the modified chitosan. 10g of modified chitosan was added. Chitosan, 19g thermoplastic polyurethane and 90g dimethylacetamide were mixed evenly to obtain a spinning solution, which was injected into a syringe for electrospinning. The electrospinning voltage was 25kV, the feed rate was 3.5mL / h, and the receiving distance was 18cm. The fibers obtained by spinning were soaked in deionized water at a temperature of 48°C for 0.7h. The soaked fibers were then taken out, washed, dried, and crushed into a state with a length of 1cm to obtain modified composite fibers.

[0040] Mix 70g of dodecylphenol polyoxyethylene ether and 0.4g of sulfuric acid, heat to 80°C, add 8.2g of epichlorohydrin at a rate of 0.15g / min, and react for 13h to obtain an intermediate; then mix 10g of triethylenetetramine and 18g of ethylene glycol, heat to 60°C, add 24g of the intermediate and 4g of dimethylmonochlorosilane, then heat to 90°C and react for 5h to obtain an emulsifier.

[0041] 9 g of modified composite fiber and 1.6 g of deionized water were mixed, and ultrasonically dispersed at a frequency of 50 kHz for 35 minutes. 57 g of polycarbonate diol, 27 g of o-xylidine ether and 3.5 g of emulsifier were added and stirred for 55 minutes. 13.5 g of cyclopentane was then added and mixed evenly to obtain a combined polyether material. The combined polyether material and 138 g of polymethylene polyphenyl isocyanate were then put into a high-pressure foaming machine and mixed evenly. The mixture was poured into a mold, foamed and molded, and demolded to obtain a low thermal conductivity foaming composition for a low-density quick-release system.

[0042] Comparative Example 1 The modified composite fiber of this comparative example was prepared by the following steps: 10g of chitosan was soaked in 70g of 1% acetic acid aqueous solution by mass percentage for 2h, and then triethylamine was added to adjust the pH to 8.5. The mixture was allowed to stand for 5min, filtered, washed, 60g of cyclopentyl methyl ether and 20g of triethylamine were added and stirred evenly. The temperature was adjusted to 0°C, and 1.1g of lauroyl chloride was added. The temperature was raised to 43°C and the reaction was carried out for 6.5h. The mixture was cooled to room temperature, and 0.3g of stearyl chloride was added and the reaction was carried out for 5h. After the reaction, the mixture was poured into 500mL of methanol, filtered, washed, and dried to obtain modified chitosan. 10g of modified chitosan, 17g of thermoplastic polyurethane and 85g of dimethylacetamide were mixed evenly to obtain a spinning solution, which was injected into a syringe for electrospinning. The electrospinning voltage was 25kV, the feed rate was 4mL / h, and the receiving distance was 17cm. The fibers obtained by spinning were crushed into a state with a length of 0.9cm to obtain modified composite fibers.

[0043] The other preparation processes were consistent with those in Example 1, and a low thermal conductivity foaming composition for a low-density quick-release system was prepared.

[0044] Comparative Example 2 The modified composite fiber of this comparative example was prepared by the following steps: 10g chitosan, 17g thermoplastic polyurethane and 85g dimethylacetamide were mixed evenly to obtain a spinning solution, which was injected into a syringe for electrospinning. The electrospinning voltage was 25kV, the feed rate was 4mL / h, and the receiving distance was 17cm. The fibers obtained by spinning were soaked in deionized water at a temperature of 45°C for 0.6h. The soaked fibers were then taken out, washed, dried, and crushed into a state with a length of 0.9cm to obtain modified composite fibers.

[0045] The other preparation processes were consistent with those in Example 1, and a low thermal conductivity foaming composition for a low-density quick-release system was prepared.

[0046] Performance testing 1. Thermal conductivity: It is measured by a thermal conductivity tester using the transient plane heat source method. The test sample is 150 mm long, 150 mm wide, and 10 mm thick.

[0047] 2. Apparent density: Tested in accordance with GB / T6343-2009 “Determination of apparent density of foamed plastics and rubber”.

[0048] 3. Compression strength: Tested using a universal material testing machine in accordance with standard GB / T8813-2008. The specimen dimensions are 100 mm long × 100 mm wide × 50 mm thick.

[0049] 4. Dimensional stability: The test is carried out in accordance with the standard GB / T8811-2008 "Compression test method for dimensional stability of rigid foam plastics". The sample size is 100 mm long × 100 mm wide × 50 mm thick.

[0050] 5. Foam closed cell rate: tested in accordance with standard GB / T10799-2008.

[0051] Table 1 Test results

[0052] Analysis of Examples 1-4 and Table 1 shows that by modifying chitosan and compounding the modified chitosan with thermoplastic polyurethane to prepare a modified composite fiber, and adding this modified composite fiber to the preparation process of a low thermal conductivity foaming composition for a low-density quick-release system, the resulting low thermal conductivity foaming composition for a low-density quick-release system has a higher foam closed cell ratio and a lower thermal conductivity coefficient.

[0053] From the analysis of Comparative Example 1 and Comparative Example 2 and in combination with Table 1, it can be seen that in the preparation process of the modified composite fiber, if the fiber is not soaked, thereby failing to increase the fiber specific surface area, or if long fatty chains are not introduced, the closed-cell rate of the foamed composition will be reduced and the thermal conductivity will be increased.

[0054] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A low thermal conductivity foaming composition for a low-density quick-release system, characterized in that: The invention is prepared from the following raw materials in parts by weight: 13-14 parts of cyclopentane, 130-140 parts of polymethylene polyphenyl isocyanate, 50-60 parts of polycarbonate diol, 25-30 parts of o-xylene ammonium ether, 1.6-1.8 parts of deionized water, 3-4 parts of emulsifier, and 7-10 parts of modified composite fiber; The preparation method of the modified composite fiber comprises the following steps: (1) Soak chitosan in an acetic acid aqueous solution, add triethylamine, let it stand, filter, wash, add a mixed solution of cyclopentyl methyl ether and triethylamine and stir evenly, then add fatty acid chloride, pour into methanol after the reaction is completed, filter, wash, and dry to obtain modified chitosan; (2) uniformly mixing the modified chitosan, thermoplastic polyurethane and dimethylacetamide to obtain a spinning solution; (3) The spinning solution is injected into a syringe for electrospinning, and the fibers obtained by spinning are soaked in deionized water. The soaked fibers are then taken out, washed, dried, and crushed to obtain modified composite fibers.

2. The low thermal conductivity foaming composition for low-density quick-release system according to claim 1, characterized in that: The preparation method of the emulsifier comprises the following steps: S1: Mix dodecylphenol polyoxyethylene ether and sulfuric acid evenly, heat to 70-85°C, add epichlorohydrin, and react for 12-15 hours to obtain an intermediate; S2: Evenly mix triethylenetetramine and ethylene glycol, raise the temperature to 50-70°C, add the intermediate and dimethylchlorosilane, then raise the temperature to 85-95°C, and react for 4-6 hours to obtain an emulsifier.

3. The low thermal conductivity foaming composition for low-density quick-release system according to claim 1, characterized in that: In the step (1), the fatty acid chloride is any two of hexanoyl chloride, stearoyl chloride and lauroyl chloride.

4. The low thermal conductivity foaming composition for low-density quick-release system according to claim 1, characterized in that: In the step (2), the mass ratio of modified chitosan, thermoplastic polyurethane and dimethylacetamide is 1:(1.5-2):(8-9.5).

5. The low thermal conductivity foaming composition for low-density quick-release system according to claim 1, characterized in that: In the step (3), the process parameters of electrospinning are: voltage 20-30 kV, receiving distance 15-20 cm, feed rate 3-5 mL / h; the average length of the modified composite fiber after crushing is 0.8-1 cm.

6. The low thermal conductivity foaming composition for low-density quick-release system according to claim 1, characterized in that: The soaking treatment in step (3) is carried out at a temperature of 40-50° C. and for a time of 0.5-1 h.

7. The low thermal conductivity foaming composition for low-density quick-release system according to claim 2, characterized in that: The addition rate of epichlorohydrin in step S1 is 0.13-0.2 g / min.

8. The low thermal conductivity foaming composition for low-density quick-release system according to claim 2, characterized in that: In the step S2, the mass ratio of triethylenetetramine, ethylene glycol, intermediate and dimethyl monochlorosilane is 1:(1.7-2):(2-2.5):(0.3-0.5).

9. A method for preparing a low thermal conductivity foaming composition for a low-density quick-release system according to claim 1, characterized in that: The steps include: a. Mixing the modified composite fiber and deionized water, performing ultrasonic dispersion, adding polycarbonate diol, o-xylidine ether and an emulsifier, mixing and stirring, and then adding cyclopentane and mixing evenly to obtain a composite polyether material; b: Mixing the combined polyether material and polymethylene polyphenyl isocyanate, pouring the mixture into a mold, foaming and molding, and demolding to obtain a low thermal conductivity foaming composition for a low-density quick-release system.

10. The method for preparing a low thermal conductivity foaming composition for a low-density quick-release system according to claim 9, characterized in that: The frequency of the ultrasonic dispersion is 30-60 kHz, and the time is 25-40 min.

Images