Polyurethane composition as well as preparation method and application thereof

Abstract

The invention provides a polyurethane composition. The polyurethane composition comprises the following raw materials: a component A: 70-90 parts of polyether polyol, 10-30 parts of polyester polyol, 5-10 parts of a chain extender, 2.5-4.5 parts of a catalyst, 2-5 parts of a foam stabilizer and 15.5-36 parts of a foaming agent; the component B comprises the following components in parts by weight: 145-147 parts of isocyanate; the chain extender comprises a first chain extender and a second chain extender, the first chain extender is a compound as shown in a structural formula 1: # imgabs 0 #, and the second chain extender is a compound as shown in a structural formula 2: # imgabs 1 #. The polyurethane composition provided by the invention is high in compression strength and hydrophobicity, and good in heat resistance.

Description

Technical Field

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

[0002] Polyurethane insulation material is a synthetic material with excellent performance, high specific strength, low thermal conductivity and other advantages. It is mainly used as thermal insulation material. Polyurethane, also known as carbamate, is a polymer compound characterized by containing many repeated carbamate groups on the main chain. Polyurethane is obtained by the gradual reaction and addition of polyisocyanate and polyhydroxy compound. By changing the number and type of functional groups, polyurethane materials with different properties and forms can be obtained.

[0003] The preparation of polyurethane is usually prepared by polymerization reaction of polyether diol or polyester diol and isocyanate and other raw materials. The polyurethane insulation material prepared with polyether diol as raw material has the effects of hydrolysis resistance and low water absorption, but its compressive strength is low. The polyurethane insulation material prepared with polyester diol as raw material has high compressive strength, but is easy to hydrolyze and has high water absorption. In order to solve the above problems, polyurethane is prepared with polyether diol, polyester diol and isocyanate as raw materials, and chain extenders are added. Commonly used chain extenders include fluorine-containing chain extenders. Fluorine-containing chain extenders are used because they contain fluorine-carbon chains with low surface energy and strong hydrophobicity. They have weak interactions with other components in polyurethane such as polyether polyols and polyester polyols at the molecular level, resulting in poor compatibility when the fluorine-containing chain extender reacts with other components, affecting the formation of bubbles and resulting in reduced mechanical properties; the obtained polyurethane composition cannot achieve strong compressive strength, low water absorption and good heat resistance. Summary of the invention

[0004] In view of the problem that the existing polyurethane preparation uses polyester diol, polyether diol and isocyanate as raw materials, and the polyurethane composition obtained by adding a fluorine-containing chain extender has reduced mechanical properties and cannot achieve strong compressive strength, low water absorption and good heat resistance, the present application provides a polyurethane composition and a preparation method and application thereof.

[0005] In a first aspect, the present invention provides a polyurethane composition comprising the following raw materials: Component A: 70-90 parts of polyether polyol, 10-30 parts of polyester polyol, 5-10 parts of chain extender, 2.5-4.5 parts of catalyst, 2-5 parts of foaming agent, 15.5-36 parts of foaming agent; Component B: 145-147 parts of isocyanate; The chain extender includes a first chain extender and a second chain extender, wherein the first chain extender is a compound shown in structural formula 1: wherein R1, R2, R3, R4, and R5 are each independently selected from at least one of an alkyl group in which at least one hydrogen atom is substituted by fluorine, an alkyl chain terminated by a hydroxyl group, and an alkyl group, and at least one of R3 and R4 is selected from an alkyl chain terminated by a hydroxyl group; The second chain extender is a compound represented by structural formula 2: Among them, R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 Each independently selected from alkyl; R6 and R7 are selected from at least one of a hydroxyl-terminated alkyl chain and an alkyl group, and at least one of R6 and R7 is selected from a hydroxyl-terminated alkyl chain.

[0006] Preferably, R1, R2, R3, R4, and R5 are each independently selected from at least one of a C3-C15 alkyl group in which at least one hydrogen atom is substituted by fluorine, a C1-C5 alkyl chain terminated with a hydroxyl group, and a C1-C5 alkyl group, and at least one of R3 and R4 is selected from a C1-C5 alkyl chain terminated with a hydroxyl group; R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 Selected from C1~C5 alkyl; R6 and R7 are selected from at least one of a hydroxyl-terminated C1-C5 alkyl chain and a C1-C5 alkyl group, and at least one of R6 and R7 is selected from a hydroxyl-terminated C1-C5 alkyl chain.

[0007] Preferably, the mass ratio of the first chain extender to the second chain extender is 1:(0.1-0.3).

[0008] Preferably, R5 is selected from a C6-C12 perfluoroalkyl group.

[0009] Preferably, the polyether polyol includes polyether polyol I having a hydroxyl value of 440-460 mgKOH / g and polyether polyol II having a hydroxyl value of 745-775 mgKOH / g; In the polyurethane composition, the amount of the polyether polyol I is 40-50 parts, and the amount of the polyether polyol II is 30-40 parts; the mass ratio of the polyether polyol I, the polyether polyol II and the polyester polyol is (1.2-5): (1-4): 1; And / or, the hydroxyl value of the polyester polyol is 230-250 mgKOH / g.

[0010] Preferably, the catalyst includes at least one of an organic salt catalyst and a tertiary amine catalyst; The organic salt catalyst includes one or more of dibutyltin dilaurate, potassium acetate, potassium isooctanoate, potassium oleate, stannous octoate, and dibutyltin dilaurate acetate; The tertiary amine catalyst includes one or more of triethylenediamine, triethylenediamine, dimethylcyclohexylamine, triethanolamine, triethylamine, trimethylbenzylamine, and dimethylethanolamine; The foam leveling agent includes one or more of silicone oil, bis-(γ-triethoxysilylpropyl) tetrasulfide, γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, vinyltriethoxysilane, and γ-methacryloxypropyltrimethoxysilane; The foaming agent includes one or two of water and monofluorodichloroethane; The isocyanate includes one or more of diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, toluene diisocyanate, dicyclohexylmethane diisocyanate, diphenylmethane-4,4-diisocyanate, xylylene diisocyanate, naphthalene-1,5-diisocyanate, p-phenylene diisocyanate, and tetramethylxylylene diisocyanate.

[0011] In a second aspect, the present application provides a method for preparing the polyurethane composition described above, comprising the following steps: Prepare the component A and the component B according to parts by weight; The component A and the component B are uniformly mixed to obtain the polyurethane composition.

[0012] Preferably, the preparation method of the first chain extender comprises the following steps: Under a protective atmosphere, compound 1, compound 2 and a first solvent are uniformly mixed, and a first heating reaction is performed to obtain a first mixture, and the first mixture is extracted and distilled under reduced pressure to obtain the first chain extender; The reaction temperature in the first heating reaction is 60-80°C, and the reaction time is 12-24h; The compound 1 is a compound represented by structural formula 3, and the compound 2 is a compound represented by structural formula 4. , wherein R3 and R4 are independently selected from alkyl and alkyl chains terminated with hydroxyl groups; and at least one of R3 and R4 is selected from alkyl chains terminated with hydroxyl groups; R2' is selected from alkenyl groups; R1 is selected from alkyl groups, and R5 is selected from alkyl groups in which at least one hydrogen atom is substituted with fluorine; The molar ratio of the compound 1 to the compound 2 is 1:(1.1-1.3); The first solvent includes one or more of an alcohol solvent, ethyl acetate, N-methylpyrrolidone, and dipropylene glycol dimethyl ether.

[0013] Preferably, the preparation method of the second chain extender comprises the following steps: Under a protective atmosphere, compound 3, compound 4 and a second solvent are uniformly mixed, a second heating reaction is performed to obtain a second mixture, and the second mixture is extracted and distilled under reduced pressure to obtain the second chain extender; The reaction temperature in the second heating reaction is 60-80°C, and the reaction time is 12-24h; The compound 3 is a compound represented by structural formula 5, and the compound 4 is a compound represented by structural formula 6. , wherein R6 and R7 are independently selected from alkyl groups and alkyl chains terminated with hydroxyl groups; and at least one of R6 and R7 is selected from alkyl chains terminated with hydroxyl groups; R2 is selected from alkenyl groups; R1 is selected from alkyl groups, and R5 is selected from alkyl groups in which at least one hydrogen atom is substituted with fluorine; R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 Each independently selected from alkyl; R 21 ', R 22 ', R 23 ', R 24 ', R 25 ', R26 ', R 27 ', R 28 ' are each independently selected from alkenyl; The molar ratio of the compound 3 to the compound 4 is 1:(8.2-8.5); The second solvent includes one or more of an alcohol solvent, ethyl acetate, N-methylpyrrolidone, and dipropylene glycol dimethyl ether.

[0014] In a third aspect, the present application provides an application of the polyurethane composition described above or a polyurethane composition prepared by the method for preparing the polyurethane composition described above in thermal insulation materials.

[0015] The polyurethane composition provided in this application has the following effects: 1) Adding 70-90 parts of polyether polyol and 10-30 parts of polyester polyol is conducive to obtaining a polyurethane composition having the characteristics of compressive strength, low water absorption and heat resistance; 2) Adding the first chain extender and the second chain extender increases the compatibility of the system. The two chain extenders work together to react with the isocyanate groups in the polyurethane prepolymer. The first chain extender and the second chain extender are introduced into the polyurethane molecular chain, and the molecular chain is extended, which is beneficial to improving the strength of the polyurethane foam cells, making the foam cells in the polyurethane composition less susceptible to external influences and compression, optimizing the best hydrophobic performance, and the polyurethane composition has strong hydrophobicity and can still maintain a low water absorption rate even in a humid environment; 3) The polyurethane composition provided in the present application has strong compressive strength, good hydrophobicity, and can effectively maintain continuous thermal insulation function. The polyurethane composition has low thermal conductivity and good heat resistance. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0017] In order to illustrate the technical solution of the present invention, specific embodiments are provided below for illustration.

[0018] In a first aspect, in one embodiment of the present invention, a polyurethane composition is provided, comprising the following raw materials: Component A: 70-90 parts of polyether polyol, 10-30 parts of polyester polyol, 5-10 parts of chain extender, 2.5-4.5 parts of catalyst, 2-5 parts of foaming agent, 15.5-36 parts of foaming agent; Component B: 145-147 parts of isocyanate; The chain extender includes a first chain extender and a second chain extender, wherein the first chain extender is a compound shown in structural formula 1: wherein R1, R2, R3, R4, and R5 are each independently selected from at least one of an alkyl group in which at least one hydrogen atom is substituted by fluorine, an alkyl chain terminated by a hydroxyl group, and an alkyl group, and at least one of R3 and R4 is selected from an alkyl chain terminated by a hydroxyl group; The second chain extender is a compound represented by structural formula 2: Among them, R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 Each independently selected from alkyl; R6 and R7 are selected from at least one of a hydroxyl-terminated alkyl chain and an alkyl group, and at least one of R6 and R7 is selected from a hydroxyl-terminated alkyl chain.

[0019] Specifically, the alkyl group includes a straight-chain alkyl group or an alkyl group containing a branch, such as a straight-chain alkyl group such as a methyl group, an ethyl group, a propyl group, or an alkyl group containing a branch such as an isobutyl group, an isopropyl group.

[0020] At least one of R3 and R4 is selected from a hydroxyl-terminated alkyl chain, which means that R3 or R4 is selected from a hydroxyl-terminated alkyl chain, or both R3 and R4 are selected from a hydroxyl-terminated alkyl chain.

[0021] R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 Each independently selected from an alkyl group, it is understood that R11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 The groups selected may be the same or different.

[0022] At least one of R6 and R7 is selected from a hydroxyl-terminated alkyl chain, which means that R6 or R7 is selected from a hydroxyl-terminated alkyl chain, or both R6 and R7 are selected from a hydroxyl-terminated alkyl chain.

[0023] Specifically, the polyurethane thermal insulation material prepared by reacting polyether polyol and isocyanate alone contains a polyether segment, and the polyurethane thermal insulation material has low water absorption, but also low compressive strength; the polyurethane thermal insulation material prepared by reacting polyester polyol and isocyanate alone has high compressive strength, but high water absorption due to easy hydrolysis; 70 to 90 parts of polyether polyol and 10 to 30 parts of polyester polyol are added to the polyurethane composition provided in the present application, and the polyether polyol and polyester polyol are used in combination, which is beneficial for the obtained polyurethane composition to have the characteristics of compressive strength, low water absorption and heat resistance.

[0024] The first chain extender is a fluorine-containing chain extender. Due to the small radius and high electronegativity of the fluorine atom and the large bond energy of the carbon-fluorine bond, the formed pores are more difficult to be compressed; the fluorocarbon chain can also significantly reduce the surface tension of water. By adjusting the proportion of the chain extender, the polyurethane polymer can have a carbon-fluorine enriched surface layer, and the formed carbon-fluorine surface layer has strong hydrophobicity. However, the inventors found that when the first chain extender is added alone during the preparation of the polyurethane composition, the first chain extender has low surface energy and strong hydrophobicity due to the fluorocarbon chain, and the interaction with other components in the polyurethane such as polyether polyols, polyester polyols, isocyanates, etc. at the molecular level is weak, resulting in poor compatibility when the first chain extender reacts with other components, affecting the formation of pores, resulting in reduced mechanical properties of the polyurethane composition. The compound shown in structural formula 2 has a unique cage-type silicone framework structure. The cage-type structure composed of silicon-oxygen bonds can effectively block water vapor molecules and also form a dense barrier layer on the surface of the polyurethane composition. If the second chain extender is added alone, the unique cage-type structure has a hydrophobic area with a rigid core, which will also make the polyurethane molecules too rigid and reduce the mechanical properties of the polyurethane composition.

[0025] In view of the above problems, the inventors found that a first chain extender and a second chain extender are added in the process of preparing a polyurethane composition, the structures of the first chain extender and the second chain extender are similar, the main structure of the second chain extender includes an organosilicon structure, which is a flexible segment and has good compatibility with polyurethane, and can reduce the rigidity of the second chain extender in synergy with the first chain extender. The second chain extender contains the same amino alcohol segment as the first chain extender, which can improve the compatibility of the first chain extender. Therefore, the second chain extender and the first chain extender system can increase the compatibility of the system, and the first chain extender and the second chain extender play their respective advantages under the synergistic effect, which can improve the strength of the polyurethane foam cells and optimize the optimal hydrophobic performance. The obtained polyurethane composition has strong compressive strength and hydrophobicity, and at the same time improves the heat resistance of the polyurethane composition, and is not easy to decompose or deteriorate at high temperatures.

[0026] The polyurethane composition provided in this application has the following effects: 1) Adding 70-90 parts of polyether polyol and 10-30 parts of polyester polyol is conducive to obtaining a polyurethane composition having the characteristics of compressive strength, low water absorption and heat resistance; 2) Adding the first chain extender and the second chain extender increases the compatibility of the system. The two chain extenders work together to react with the isocyanate groups in the polyurethane prepolymer. The first chain extender and the second chain extender are introduced into the polyurethane molecular chain, and the molecular chain is extended, which is beneficial to improving the strength of the polyurethane foam cells, making the foam cells in the polyurethane composition less susceptible to external influences and compression, optimizing the best hydrophobic performance, and the polyurethane composition has strong hydrophobicity and can still maintain a low water absorption rate even in a humid environment; 3) The polyurethane composition provided in the present application has strong compressive strength, good hydrophobicity, and can effectively maintain continuous thermal insulation function. The polyurethane composition has low thermal conductivity and good heat resistance.

[0027] In some embodiments, R1, R2, R3, R4, and R5 are each independently selected from at least one of a C3-C15 alkyl group in which at least one hydrogen atom is substituted by fluorine, a C1-C5 alkyl chain terminated with a hydroxyl group, and a C1-C5 alkyl group, and at least one of R3 and R4 is selected from a C1-C5 alkyl chain terminated with a hydroxyl group.

[0028] Specifically, the hydroxyl-terminated C1~C5 alkyl chain may be, for example, a -CH2CH(CH3)OH group, -CH2CH2CH2OH, -CH2CH(CH2CH3)CH2OH, or the like.

[0029] The first chain extender and the second chain extender both contain -OH and -NH- groups. The first chain extender and the second chain extender work together to increase the compatibility of the system, so that the first chain extender and the second chain extender can react with the isocyanate group well, consume part of the isocyanate, and shift the original reaction balance of the polyether polyol, polyester polyol and isocyanate, so as to promote the reaction to generate a polyurethane with a longer molecular chain; the molecular chain structure is adjusted, so that the entanglement and interaction force between the polyurethane molecular chains are enhanced, and the mechanical properties of the polyurethane composition are improved.

[0030] In some preferred embodiments, R3 and R4 are selected from C2~C4 alkyl chains terminated with hydroxyl groups, R2 is selected from C2~C4 alkyl groups, R1 is selected from C2~C4 alkyl groups, and R5 is selected from C5~C10 alkyl groups in which at least one hydrogen atom is replaced by fluorine.

[0031] R1, R2, R3, R4, and R5 in the first chain extender are each selected from the above-mentioned groups, and contain more hydroxyl groups, so that more hydroxyl groups can react with isocyanate groups. At the same time, the overall molecular structure of the chain extender is relatively compact, the molecular distance is relatively small, and the interaction force is enhanced. It cooperates with the second chain extender to help improve the hardness of the polyurethane combination and improve the mechanical properties.

[0032] In some preferred embodiments, R5 is selected from a C6-C12 perfluoroalkyl group, which contains more fluorine elements, which is beneficial to improving the hydrophobic properties of the polyurethane composition.

[0033] In some embodiments, R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 is selected from C1~C5 alkyl; R6 and R7 are selected from at least one of hydroxyl-terminated C1~C5 alkyl chains and C1~C5 alkyl groups. Specifically, the second chain extender is selected from the above groups, and the molecular chain is short, and the intermolecular force between the second chain extender and the first chain extender is enhanced, which is more conducive to increasing the compatibility of the system, increasing the hardness of the polyurethane composition, and improving the mechanical properties of the polyurethane composition.

[0034] In some preferred embodiments, R6 and R7 are selected from hydroxyl-terminated C1~C5 alkyl chains.

[0035] Specifically, R6 and R7 are both selected from hydroxyl-terminated C1~C5 alkyl chains. The second chain extender contains more hydroxyl groups, which increases the compatibility of the reaction system, can react with more isocyanate groups, and more polyurethane prepolymer molecules are connected, synergistically improving the mechanical properties of the polyurethane composition with the first chain extender.

[0036] In some embodiments, the mass ratio of the first chain extender to the second chain extender is 1:(0.1-0.3).

[0037] Specifically, the mass ratio of the first chain extender to the second chain extender is in the range of 1:(0.1-0.3), and the amount of the second chain extender used is small, which reduces the rigidity of the polyurethane composition and can also increase the compatibility of the system, which is conducive to the first chain extender and the second chain extender to better play a synergistic role, improve the mechanical properties and hydrophobic properties of the polyurethane composition, and improve the heat resistance of the polyurethane composition, so that the polyurethane composition is not easy to decompose or deteriorate at high temperatures.

[0038] Specifically, the mass ratio of the first chain extender to the second chain extender can be 1:0.1, 1:0.15, 1:0.18, 1:0.2, 1:0.25, 1:0.3, etc., as long as the mass ratio of the first chain extender to the second chain extender is within the range of 1:(0.1-0.3).

[0039] If the mass ratio of the first chain extender to the second chain extender added to the polyurethane composition is lower than 1: (0.1-0.3), the content of the second chain extender is too high, the rigidity of the polyurethane is strong, and the mechanical properties of the polyurethane are reduced; if the mass ratio of the first chain extender to the second chain extender is higher than 1: (0.1-0.3), the content of the second chain extender is low, the compatibility of the first chain extender with components such as isocyanate is poor, the formation of bubbles is affected, and the compatibility of the polyurethane composition is reduced.

[0040] In some embodiments, the polyether polyol includes polyether polyol I having a hydroxyl value of 440-460 mgKOH / g and polyether polyol II having a hydroxyl value of 745-775 mgKOH / g; In the polyurethane composition, the proportion of the polyether polyol I is 40-50 parts, and the proportion of the polyether polyol II is 30-40 parts; the mass ratio of the polyether polyol I, the polyether polyol II and the polyester polyol is (1.2-5):(1-4):1.

[0041] Specifically, in the polyurethane composition, the polyether polyol I accounts for 40 to 50 parts, and the polyether polyol II accounts for 30 to 40 parts. In the polyurethane composition, the mass ratio of the polyether polyol I, the polyether polyol II and the polyester polyol is (1.2 to 5): (1 to 4): 1, which can better control the reaction speed and the molecular weight of the generated polyurethane, adjust the hardness and flexibility balance of the polyurethane composition, and ensure good water resistance and heat resistance.

[0042] In some embodiments, the polyester polyol has a hydroxyl value of 230-250 mgKOH / g.

[0043] Similarly, limiting the hydroxyl value of the polyester polyol to the range of 230~250mgKOH / g is conducive to regulating the reaction rate, controlling the molecular weight of the generated polyurethane, and ensuring that the obtained polyurethane composition has the characteristics of compressive strength, low water absorption and heat resistance.

[0044] In some embodiments, the catalyst includes at least one of an organic salt catalyst and a tertiary amine catalyst; The organic salt catalyst includes one or more of dibutyltin dilaurate, potassium acetate, potassium isooctanoate, potassium oleate, stannous octoate, and dibutyltin dilaurate acetate; The tertiary amine catalyst includes one or more of triethylenediamine, triethylenediamine, dimethylcyclohexylamine, triethanolamine, triethylamine, trimethylbenzylamine, and dimethylethanolamine.

[0045] The catalyst is selected from at least one of an organic salt catalyst and a tertiary amine catalyst, which is beneficial to improving the reaction rate.

[0046] The foam leveling agent includes one or more of silicone oil, bis-(γ-triethoxysilylpropyl) tetrasulfide, γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, vinyltriethoxysilane, and γ-methacryloxypropyltrimethoxysilane.

[0047] Specifically, the foam leveling agent is selected from at least one of the above types, which is beneficial to improving the pore structure, making the pores more uniform and dense, and improving the foam stability.

[0048] In some embodiments, the blowing agent includes one or both of water and monofluorodichloroethane.

[0049] Specifically, the foaming agent is selected from at least one of the above types. The foaming agent generates gas during the preparation of the polyurethane composition, and the generated gas forms cells in the polyurethane.

[0050] In some embodiments, the isocyanate includes one or more of diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, toluene diisocyanate, dicyclohexylmethane diisocyanate, diphenylmethane-4,4,-diisocyanate, xylylene diisocyanate, naphthalene-1,5-diisocyanate, p-phenylene diisocyanate, and tetramethylxylylene diisocyanate.

[0051] In a second aspect, the present application provides a method for preparing the polyurethane composition described above, comprising the following steps: Prepare the component A and the component B according to parts by weight; The component A and the component B are uniformly mixed to obtain the polyurethane composition.

[0052] The polyurethane composition provided in the present application is obtained by directly mixing component A and component B. The preparation method is simple. The obtained polyurethane composition has strong compressive strength and hydrophobicity, and can effectively maintain continuous thermal insulation function. The polyurethane composition has low thermal conductivity and good heat resistance.

[0053] The specific preparation method of the polyurethane composition is as follows: Prepare component A and component B according to parts by weight; Component A: 70-90 parts of polyether polyol, 10-30 parts of polyester polyol, 5-10 parts of chain extender, 2.5-4.5 parts of catalyst, 2-5 parts of foam leveler, 15.5-36 parts of foaming agent; the chain extender includes a first chain extender and a second chain extender; Component B: 145-147 parts of isocyanate; The polyurethane composition is obtained by uniformly mixing the A component and the B component.

[0054] Specifically, in the polyurethane composition, the amount of polyether polyol can be 70 parts, 72 parts, 75 parts, 78 parts, 80 parts, 83 parts, 85 parts, 87 parts, 90 parts, etc., as long as the polyether polyol is in the range of 70 to 90 parts. In the polyurethane composition, the amount of polyester polyol can be 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 23 parts, 26 parts, 29 parts, 30 parts, etc., as long as the polyester polyol is in the range of 10 to 30 parts. In the polyurethane composition, the amount of chain extender can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc., as long as the amount of chain extender is in the range of 10 to 30 parts. In the polyurethane composition, the amount of the catalyst can be 2.5 parts, 2.8 parts, 3.0 parts, 3.2 parts, 3.5 parts, 3.7 parts, 3.9 parts, 4.0 parts, 4.2 parts, 4.5 parts, etc., as long as the amount of the catalyst is within the range of 2.5 to 4.5 parts.

[0055] In the polyurethane composition, the number of parts of isocyanate is 145, 146, 147, etc.

[0056] In the polyurethane composition, the amount of the foaming agent can be 2 parts, 2.3 parts, 2.5 parts, 2.8 parts, 3.0 parts, 3.3 parts, 3.5 parts, 4.0 parts, 4.3 parts, 4.5 parts, 5.0 parts, etc., as long as the amount of the foaming agent is within the range of 2 to 5 parts. In the polyurethane composition, the amount of the foaming agent can be 15.5, 17, 17.5, 18, 19, 20, 23, 25, 26, 28, 30, 32, 35, 36 parts, etc., as long as the amount of the foaming agent is within the range of 15.5 to 36 parts.

[0057] In some embodiments, the method for preparing the first chain extender comprises the following steps: Under a protective atmosphere, compound 1, compound 2 and a first solvent are uniformly mixed, and a first heating reaction is performed to obtain a first mixture, and the first mixture is extracted and distilled under reduced pressure to obtain the first chain extender; The compound 1 is a compound represented by structural formula 3, and the compound 2 is a compound represented by structural formula 4. , Among them, R3 and R4 are independently selected from alkyl and hydroxyl-terminated alkyl chains; and at least one of R3 and R4 is selected from hydroxyl-terminated alkyl chains; R2' is selected from alkenyl; R1 is selected from alkyl, and R5 is selected from alkyl in which at least one hydrogen atom is substituted by fluorine.

[0058] Specifically, the protective atmosphere refers to a protective gas filled in a vacuum state, and the protective gas includes one of a rare gas and nitrogen. The rare gas includes helium, argon, etc.

[0059] Compound 1 is a compound shown in structural formula 3, and compound 2 is a compound shown in structural formula 4. In the compound shown in structural formula 4, R2 is selected from an alkenyl group and contains a carbon-carbon double bond. When compound 1 and compound 2 react, the carbon-carbon double bond reacts with the amine group in compound 1 to generate the compound shown in structural formula 1.

[0060] After the first heating reaction is completed, a first mixture is obtained, and the first mixture is extracted with distilled water or deionized water to remove unreacted reactant compound 1 and the first solvent. The number of extractions is greater than or equal to 1, and the number of extractions is preferably greater than 1. After the extraction is completed, the excess compound 2 and water are removed by vacuum distillation to obtain a first chain extender.

[0061] In some embodiments, the reaction temperature in the first heating reaction is 60-80° C., and the reaction time is 12-24 hours.

[0062] Specifically, the reaction temperature in the first heating reaction can be 60°C, 62°C, 65°C, 67°C, 68°C, 70°C, 73°C, 75°C, 77°C, 79°C, 80°C, etc., as long as the reaction temperature of the first heating reaction is within the range of 60°C to 80°C. If the reaction temperature of the first heating reaction is lower than 60°C, compound 1 and compound 2 cannot react effectively; if the reaction temperature of the first heating reaction is higher than 80°C, the reaction temperature is too high and the reaction by-products increase.

[0063] In some embodiments, the molar ratio of compound 1 to compound 2 is 1:(1.1-1.3).

[0064] Specifically, the molar ratio of compound 1 to compound 2 is within the range of 1:(1.1-1.3), which can generate the compound shown in structural formula 1 at a lower cost.

[0065] In some embodiments, the first solvent includes one or more of an alcohol solvent, ethyl acetate, N-methylpyrrolidone, and dipropylene glycol dimethyl ether.

[0066] Alcohol solvents include methanol, ethanol, isopropanol, etc.

[0067] In some preferred embodiments, compound 1 is diisopropanolamine, and compound 2 is perfluorooctyl ethyl acrylate.

[0068] It should be noted that, under a protective atmosphere, compound 1 and compound 2 are mixed uniformly; at the same time, under a protective atmosphere, the mixture is heated to 60-80° C. for reaction.

[0069] In some embodiments, the method for preparing the second chain extender comprises the following steps: Under a protective atmosphere, compound 3, compound 4 and a second solvent are uniformly mixed, a second heating reaction is performed to obtain a second mixture, and the second mixture is extracted and distilled under reduced pressure to obtain the second chain extender; The compound 3 is a compound represented by structural formula 5, and the compound 4 is a compound represented by structural formula 6. , wherein R6 and R7 are independently selected from alkyl groups and alkyl chains terminated with hydroxyl groups; and at least one of R6 and R7 is selected from alkyl chains terminated with hydroxyl groups; R2 is selected from alkenyl groups; R1 is selected from alkyl groups, and R5 is selected from alkyl groups in which at least one hydrogen atom is substituted with fluorine; R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R17 , R 18 Each independently selected from alkyl; R 21 ', R 22 ', R 23 ', R 24 ', R 25 ', R 26 ', R 27 ', R 28 ' are each independently selected from alkenyl.

[0070] Specifically, R 21 ', R 22 ', R 23 ', R 24 ', R 25 ', R 26 ', R 27 ', R 28 ' are independently selected from alkenyl groups, contain carbon-carbon double bonds, and structural formula 5 contains amine groups. The amine groups in compound 3 react with the carbon-carbon double bonds in compound 4 to generate the compound shown in structural formula 2. Similarly, the second mixture is extracted to remove the unreacted reactant compound 3 and the second solvent at the same time. The number of extractions is greater than or equal to 1, and the number of extractions is preferably greater than 1; after the extraction, the excess compound 4 and water are removed by vacuum distillation to obtain the second chain extender.

[0071] In some embodiments, the reaction temperature in the second heating reaction is 60-80° C., and the reaction time is 12-24 hours.

[0072] Specifically, the reaction temperature in the second heating reaction can be 60°C, 62°C, 65°C, 67°C, 68°C, 70°C, 73°C, 75°C, 77°C, 79°C, 80°C, etc., as long as the reaction temperature of the second heating reaction is within the range of 60°C to 80°C. If the reaction temperature of the second heating reaction is lower than 60°C, compound 3 and compound 4 cannot react effectively; if the reaction temperature of the second heating reaction is higher than 80°C, the reaction temperature is too high and the reaction by-products increase.

[0073] In some embodiments, the molar ratio of the compound 3 to the compound 4 is 1:(8.2~8.5).

[0074] Specifically, the molar ratio of compound 3 to compound 4 is within the range of 1:(8.2-8.5), which can generate the compound shown in structural formula 2 at a lower cost.

[0075] In some embodiments, the second solvent includes one or more of an alcohol solvent, ethyl acetate, N-methylpyrrolidone, and dipropylene glycol dimethyl ether.

[0076] Specifically, alcohol solvents include methanol, ethanol, isopropanol, and the like.

[0077] In some preferred embodiments, compound 3 is diisopropanolamine. 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 Each independently selected from ethyl, R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 Each is independently selected from vinyl.

[0078] It should be noted that, under a protective atmosphere, compound 3 and compound 4 are mixed uniformly; at the same time, under a protective atmosphere, the mixture is heated to 60-80° C. for reaction.

[0079] In a third aspect, the present application provides an application of the polyurethane composition described above or a polyurethane composition prepared by the method for preparing the polyurethane composition described above in thermal insulation materials.

[0080] The polyurethane composition provided in the present application can be used as thermal insulation materials, such as thermal insulation in the construction field, industrial thermal insulation field, cold chain logistics field, etc.

[0081] Further preferably, the polyurethane composition is used as a thermal insulation material in the construction field, such as injecting the polyurethane composition into the interlayer between the working pipe and the outer protective pipe for use as a thermal insulation material.

[0082] The present invention is further described below by way of examples.

[0083] Example 1 S1 Preparation of the first chain extender: Raw materials: compound 1 is diisopropanolamine, compound 2 is perfluorooctyl ethyl acrylate; the first solvent is methanol; Preparation: Add 100g of perfluorooctyl ethyl acrylate, 30g of diisopropanolamine, and 800mL of methanol into a clean three-necked flask, stir evenly in a nitrogen atmosphere, and then transfer to a 60°C oil bath. After reacting for 12 hours, cool to room temperature, extract with distilled water several times to remove methanol and unreacted diisopropanolamine, and then remove excess perfluorooctyl ethyl acrylate and deionized water by reduced pressure distillation to finally obtain the product first chain extender.

[0084] S2: Preparation of the second chain extender: Raw materials: Compound 3 is diisopropanolamine, R in compound 4 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 Each independently selected from ethyl, R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 Each is independently selected from vinyl. The second solvent is isopropanol.

[0085] Preparation: Add 100g of the above compound 4, 83.6g of diisopropanolamine, and 700mL of isopropanol into a clean three-necked flask, stir evenly in a nitrogen atmosphere, and then transfer to an 80°C oil bath. After reacting for 24 hours, cool to room temperature, extract with distilled water several times to remove the solvent isopropanol and unreacted diisopropanolamine, and then remove excess compound 4 and deionized water by reduced pressure distillation to obtain the product second chain extender.

[0086] S3: Preparation of polyurethane S31: Raw materials: Polyether polyol I is a product of Bluestar Dongda DV-125, with a hydroxyl value of 440~460KOH / g. Polyether polyol II is a product of Jining Lido 403, with a hydroxyl value of 745~775KOH / g. Polyester polyol is a product of Jining Lido NLD-240B, with a hydroxyl value of 230~250KOH / g. The organic salt catalyst is dibutyltin dilaurate, which is a product of Jinan Dahui Chemical T-2; the tertiary amine catalyst is triethylenediamine, which is a product of Henan Bangrun Chemical TEDA; the first chain extender prepared in step S1 and the second chain extender prepared in step S2; the foaming agent is water and monofluorodichloroethane, and monofluorodichloroethane is purchased from Jinan Decheng Chemical; the foaming agent is purchased from Jiangsu Meside Company.

[0087] The isocyanate is polymethylene polyphenyl polyisocyanate, Wanhua PM-200 product.

[0088] S32: Preparation Component A: 45 parts of polyether polyol I, 35 parts of polyether polyol II, 20 parts of polyester polyol, 8 parts of chain extender, 2.5 parts of dibutyltin dilaurate, 1 part of triethylenediamine, 0.8 parts of water, 25 parts of monofluorodichloroethane, 3 parts of foaming agent; the mass ratio of the first chain extender to the second chain extender in the chain extender is 1:0.2.

[0089] Component B: 150 parts of polymethylene polyphenyl polyisocyanate.

[0090] The component A and the component B are mixed evenly to obtain the polyurethane composition, which is poured into the interlayer between the working pipe and the outer protective pipe for use as a heat-insulating material.

[0091] Examples 2 to 14 and Comparative Examples 1 to 7 The steps of Examples 2 to 14 and Comparative Examples 1 to 7 are similar to those of Example 1, except that the number of components of polyether polyol I, polyether polyol II, polyester polyol, chain extender, dibutyltin dilaurate, triethylenediamine, water, monofluorodichloroethane, foam leveler, and polymethylene polyphenyl polyisocyanate is different; and the mass ratio of the first chain extender to the second chain extender is different. See Table 1 for details.

[0092] Table 1 Comparative Example 8 Most of the steps of this comparative example are the same as those of Example 1, except that the second chain extender does not conform to the compound shown in Structural Formula 2, and the second chain extender is The rest is the same as Example 1.

[0093] Performance Testing The polyurethane compositions prepared in the above embodiments and comparative examples were used to prepare test samples and the following tests were performed.

[0094] 1. Compression strength The sample size is 50 mm×50 mm×50 mm. Measure the sample size to 0.05 mm, measure at least three points, and take the average value. Place the sample between the platens and apply the compressive load at the speed specified in GB / T8813-2018. The relative deformation must be at least 10%. After the sample is destroyed, record the load number.

[0095] 2. Density A rectangular parallelepiped with a regular shape is cut out of the polyurethane composition, the volume is calculated, and then it is placed on a balance to be weighed to prevent the pressure around the sample from affecting the measurement result; density = mass / volume.

[0096] 3. Water absorption The polyurethane foam prepared from the polyurethane composition was immersed in normal pressure boiling water for 90 minutes, and the mass difference before and after was calculated. The water absorption rate = mass difference / original mass.

[0097] 4. Thermal conductivity The heat flow meter method is a comparative method based on the principle of one-dimensional steady-state thermal conductivity. The sample is inserted between two plates, and a constant unidirectional heat flow is passed in the vertical direction. The heat flow through the sample is measured using a calibrated heat flow sensor, which is in contact with the sample between the plate and the sample. The heat flow method is suitable for low thermal conductivity materials. During the test, the sample is clamped between two heat flow sensors. After the temperature gradient stabilizes, the thickness of the sample, the temperature gradient between the upper and lower plates, and the heat flow through the sample are measured to calculate the absolute value of the thermal conductivity. It is suitable for testing materials with a thermal conductivity range of 0.001~50W / m•K. Test the thermal conductivity of the sample at 50°C.

[0098] 5. Heat resistance test The size of the polyurethane composition sample obtained was 100*100*50 mm. After the polyurethane foam was prepared, it was placed in a 200°C oven and stored for 120 hours before testing the heat resistance.

[0099] The above test results are shown in Table 2. It should be noted that the requirements in Table 2 are based on the requirements for thermal insulation materials in the construction field.

[0100] Table 2 It can be seen from Tables 1 and 2 that, in comparison between Example 1 and Comparative Examples 1-3, there is no first chain extender and second chain extender in Comparative Example 1, and the compressive strength is low, the water absorption rate is high, and the heat resistance is poor; in Comparative Example 2, only polyether polyol is added, and a large amount of polyether polyol is added. Although the content of polyether polyol is greater than 70-90 parts, the thermal conductivity of the polyurethane composition increases, the heat resistance is poor, and the compressive strength is low; in Comparative Example 3, the content of polyester polyol added is greater than 10-30 parts, and the polyether polyol is in the range of 70-90 parts. Although the obtained polyurethane composition has high compressive strength, it has poor water absorption, large thermal conductivity, and poor thermal insulation performance; Comparison between Example 1 and Comparative Examples 1-3 shows that 70-90 parts of polyether polyol, 10-30 parts of polyester polyol, and 145-147 parts of isocyanate are added to the polyurethane composition, and the polyurethane composition obtained under the action of the catalyst, the first chain extender, the second chain extender, the uniform foaming agent, and the foaming agent has high compressive strength and a density of ≥60kg / m 3 , low water absorption, small thermal conductivity, good thermal insulation performance and good heat resistance.

[0101] Comparison of Examples 1-3 and Comparative Examples 4-7 shows that the first chain extender or the second chain extender is added alone in Comparative Examples 6 and 7, and the compressive strength is slightly low and the water absorption rate is high; the total number of chain extenders added in Comparative Example 4 is less than 5-10 parts, and it is speculated that the chain extender contained is small, the system compatibility is poor, and the obtained polyurethane composition has high water absorption rate, poor heat resistance, and low compressive strength; the total number of chain extenders added in Comparative Example 5 is higher than 5-10 parts, and it is speculated that because there are too many chain extenders, the stacking mode of the molecular chains is changed, the free volume is reduced, and the thermal insulation effect is weakened, and the obtained polyurethane composition has high thermal conductivity and poor thermal insulation effect; Comparison of Example 1 and Comparative Examples 4-7 shows that the total number of chain extenders in the polyurethane composition is 5-10 parts, and the chain extender includes the first chain extender shown in Structural Formula 1 and the second chain extender shown in Structural Formula 2, and the obtained polyurethane composition has high compressive strength, high water absorption rate, good heat resistance, small thermal conductivity, and good thermal insulation effect.

[0102] By comparing Examples 1, 4-8 with Examples 11 and 12, the proportion of polyester polyol and the proportion of isocyanate are adjusted according to the polyether polyol, indicating that the proportion of polyether polyol I is 40-50 parts, and the proportion of polyether polyol II is 30-40 parts; the mass ratio of polyether polyol I, the polyether polyol II and the polyester polyol is in the range of (1.2-5): (1-4): 1, and the obtained polyurethane composition has high compressive strength, high water absorption, good heat resistance, small thermal conductivity and good thermal insulation effect.

[0103] Comparing Example 1, Example 9, Example 10 with Example 13, Example 14, the mass ratio of the first chain extender to the second chain extender is lower than 1:0.1, the second chain extender contained is less, the system incompatibility problem still exists, the compressive strength of the polyurethane is low, and the water absorption rate is high; the mass ratio of the first chain extender to the second chain extender is higher than 1:0.3, the content of the second chain extender contained is high, the rigidity is strong, and the mechanical properties of the obtained polyurethane composition are poor; It indicates that when the mass ratio of the first chain extender to the second chain extender is within the range of 1: (0.1~0.3), the obtained polyurethane composition has better mechanical properties.

[0104] Comparing Example 1 with Comparative Example 8, the second chain extender added in Comparative Example 8 does not satisfy the compound shown in Structural Formula 2. Although it also contains a cage structure composed of a silicon-oxygen bond, it does not satisfy the compound shown in Structural Formula 2. The two chain extenders in Comparative Example 8 cannot achieve a good synergistic effect, the chain extender has poor compatibility with the components, high compression strength, and high water absorption. This indicates that the added second chain extender satisfies the compound shown in Structural Formula 2, and the first chain extender satisfies the compound shown in Structural Formula 1. The first chain extender and the second chain extender work together to improve the strength of the polyurethane foam cells and optimize the optimal hydrophobic performance. The obtained polyurethane composition has strong compression strength and good hydrophobicity, and can effectively maintain continuous thermal insulation function. The polyurethane composition has low thermal conductivity and good heat resistance.

[0105] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the technical solutions described in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A polyurethane composition, characterized in that Including the following ingredients: Component A: 70-90 parts of polyether polyol, 10-30 parts of polyester polyol, 5-10 parts of chain extender, 2.5-4.5 parts of catalyst, 2-5 parts of foaming agent, 15.5-36 parts of foaming agent; Component B: 145-147 parts of isocyanate; The chain extender includes a first chain extender and a second chain extender, wherein the first chain extender is a compound shown in structural formula 1: wherein R1, R2, R3, R4, and R5 are each independently selected from at least one of an alkyl group in which at least one hydrogen atom is substituted by fluorine, an alkyl chain terminated by a hydroxyl group, and an alkyl group, and at least one of R3 and R4 is selected from an alkyl chain terminated by a hydroxyl group; The second chain extender is a compound represented by structural formula 2: Among them, R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 Each independently selected from alkyl; R6 and R7 are selected from at least one of a hydroxyl-terminated alkyl chain and an alkyl group, and at least one of R6 and R7 is selected from a hydroxyl-terminated alkyl chain.

2. The polyurethane composition according to claim 1, characterized in that R1, R2, R3, R4, and R5 are each independently selected from at least one of a C3-C15 alkyl group in which at least one hydrogen atom is substituted by fluorine, a C1-C5 alkyl chain terminated with a hydroxyl group, and a C1-C5 alkyl group, and at least one of R3 and R4 is selected from a C1-C5 alkyl chain terminated with a hydroxyl group; R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 , R 21 , R 22 , R 23 , R 24 , R 25 , R 26 , R 27 , R 28 Selected from C1~C5 alkyl; R6 and R7 are selected from at least one of a hydroxyl-terminated C1-C5 alkyl chain and a C1-C5 alkyl group, and at least one of R6 and R7 is selected from a hydroxyl-terminated C1-C5 alkyl chain.

3. The polyurethane composition according to claim 1 or 2, characterized in that The mass ratio of the first chain extender to the second chain extender is 1:(0.1-0.3).

4. The polyurethane composition according to claim 3, characterized in that R5 is selected from a C6-C12 perfluoroalkyl group.

5. The polyurethane composition according to claim 1, characterized in that The polyether polyols include polyether polyol I with a hydroxyl value of 440-460 mgKOH / g and polyether polyol II with a hydroxyl value of 745-775 mgKOH / g; In the polyurethane composition, the amount of the polyether polyol I is 40-50 parts, and the amount of the polyether polyol II is 30-40 parts; the mass ratio of the polyether polyol I, the polyether polyol II and the polyester polyol is (1.2-5): (1-4): 1; And / or, the hydroxyl value of the polyester polyol is 230-250 mgKOH / g.

6. The polyurethane composition according to claim 1, characterized in that The catalyst comprises at least one of an organic salt catalyst and a tertiary amine catalyst; The organic salt catalyst includes one or more of dibutyltin dilaurate, potassium acetate, potassium isooctanoate, potassium oleate, stannous octoate, and dibutyltin dilaurate acetate; The tertiary amine catalyst includes one or more of triethylenediamine, triethylenediamine, dimethylcyclohexylamine, triethanolamine, triethylamine, trimethylbenzylamine, and dimethylethanolamine; The foam leveling agent includes one or more of silicone oil, bis-(γ-triethoxysilylpropyl) tetrasulfide, γ-aminopropyltriethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, vinyltriethoxysilane, and γ-methacryloxypropyltrimethoxysilane; The foaming agent includes one or two of water and monofluorodichloroethane; The isocyanate includes one or more of diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, toluene diisocyanate, dicyclohexylmethane diisocyanate, diphenylmethane-4,4-diisocyanate, xylylene diisocyanate, naphthalene-1,5-diisocyanate, p-phenylene diisocyanate, and tetramethylxylylene diisocyanate.

7. A method for preparing a polyurethane composition according to any one of claims 1 to 6, characterized in that: The following steps are involved: Prepare the component A and the component B according to parts by weight; The component A and the component B are uniformly mixed to obtain the polyurethane composition.

8. The method for preparing the polyurethane composition according to claim 7, characterized in that: The preparation method of the first chain extender comprises the following steps: Under a protective atmosphere, compound 1, compound 2 and a first solvent are uniformly mixed, and a first heating reaction is performed to obtain a first mixture, and the first mixture is extracted and distilled under reduced pressure to obtain the first chain extender; The reaction temperature in the first heating reaction is 60-80°C, and the reaction time is 12-24h; The compound 1 is a compound represented by structural formula 3, and the compound 2 is a compound represented by structural formula 4. 、 wherein R3 and R4 are independently selected from alkyl and alkyl chains terminated with hydroxyl groups; and at least one of R3 and R4 is selected from alkyl chains terminated with hydroxyl groups; R2' is selected from alkenyl groups; R1 is selected from alkyl groups, and R5 is selected from alkyl groups in which at least one hydrogen atom is substituted with fluorine; The molar ratio of the compound 1 to the compound 2 is 1:(1.1-1.3); The first solvent includes one or more of an alcohol solvent, ethyl acetate, N-methylpyrrolidone, and dipropylene glycol dimethyl ether.

9. The method for preparing the polyurethane composition according to claim 7, characterized in that: The preparation method of the second chain extender comprises the following steps: Under a protective atmosphere, compound 3, compound 4 and a second solvent are uniformly mixed, a second heating reaction is performed to obtain a second mixture, and the second mixture is extracted and distilled under reduced pressure to obtain the second chain extender; The reaction temperature in the second heating reaction is 60-80°C, and the reaction time is 12-24h; The compound 3 is a compound represented by structural formula 5, and the compound 4 is a compound represented by structural formula 6. 、 wherein R6 and R7 are independently selected from alkyl groups and alkyl chains terminated with hydroxyl groups; and at least one of R6 and R7 is selected from alkyl chains terminated with hydroxyl groups; R2 is selected from alkenyl groups; R1 is selected from alkyl groups, and R5 is selected from alkyl groups in which at least one hydrogen atom is substituted with fluorine; R 11 , R 12 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 Each independently selected from alkyl; R 21 ', R 22 ', R 23 ', R 24 ', R 25 ', R 26 ', R 27 ', R 28 ' are each independently selected from alkenyl; The molar ratio of the compound 3 to the compound 4 is 1:(8.2-8.5); The second solvent includes one or more of an alcohol solvent, ethyl acetate, N-methylpyrrolidone, and dipropylene glycol dimethyl ether.

10. Use of a polyurethane composition as claimed in any one of claims 1 to 6 or a polyurethane composition prepared by the method for preparing the polyurethane composition as claimed in any one of claims 7 to 9 in thermal insulation materials.

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