Moisture-curing reaction type polyurethane hot melt adhesive for shoes and preparation method of moisture-curing reaction type polyurethane hot melt adhesive

Abstract

The invention relates to the field of adhesives, and particularly discloses a moisture-curing reaction type polyurethane hot melt adhesive for shoes and a preparation method of the moisture-curing reaction type polyurethane hot melt adhesive. The moisture-curing reaction type polyurethane hot melt adhesive for the shoes is prepared from the following raw materials: polyester polyol, polyether polyol, isocyanate, composite coupling agent modified kaolin, a chain extender, an antioxidant and a catalyst. Wherein the composite coupling agent modified kaolin is prepared from the following raw materials: a titanate coupling agent, an aluminate coupling agent and nano kaolin, the nano kaolin can form a microscopic barrier structure in the hot melt adhesive, the porosity is reduced, the permeation of water is reduced, the erosion of water molecules to the internal structure of the adhesive is reduced, and through the modification effect of the composite coupling agent, the thermal conductivity of the adhesive is improved. The compatibility of the nano kaolin is improved, and a compact adhesive layer is formed, so that the water resistance of the hot melt adhesive is improved.

Description

Technical Field

[0001] The invention relates to the field of adhesives, and in particular to a moisture-curing reactive polyurethane hot melt adhesive for shoes and a preparation method thereof. Background Art

[0002] As a solvent-free and environmentally friendly adhesive, reactive polyurethane (PUR) hot melt adhesive has the advantages of excellent bonding performance, mechanical properties and low VOC emissions, and has been widely used in various industrial fields. Reactive polyurethane hot melt adhesive is heated and melted under the condition of inhibiting chemical reaction to form a fluid state that is easy to apply. Subsequently, when the two adherends are bonded, the adhesive layer will quickly condense and play a bonding role. Finally, by reacting with moisture in the air or attached to the surface of the adherend, chain extension is achieved to generate a high molecular polymer with high polymerization force, thereby significantly improving adhesion and heat resistance.

[0003] The main raw materials of polyurethane hot melt adhesive are polyisocyanate and polyol. Among them, polyester polyol contains a large number of ester bonds (-COO-), which have strong polarity, cohesive strength and crystallization properties, and the hot melt adhesive obtained often has good bonding properties. However, since the ester group is easily hydrolyzed at high temperatures, the bonding strength is reduced, especially in a humid environment, and its water resistance is poor. This problem is particularly prominent in footwear products, because shoes often need to withstand the test of humid environments such as washing during use, and are prone to debonding. Summary of the invention

[0004] In order to improve the problem of poor water resistance of polyurethane hot melt adhesive and extend the service life of the hot melt adhesive, the present application provides a moisture-curing reactive polyurethane hot melt adhesive for shoes and a preparation method thereof.

[0005] In the first aspect, the present application provides a moisture-curing reactive polyurethane hot melt adhesive for shoes, which adopts the following technical scheme: a moisture-curing reactive polyurethane hot melt adhesive for shoes, which is prepared from the following raw materials, in parts by weight: 20-30 parts of polyester polyol, 40-50 parts of polyether polyol, 25-35 parts of isocyanate, 10-20 parts of composite coupling agent modified kaolin, 2-4 parts of chain extender, 0.5-0.7 parts of antioxidant, and 0.02-0.04 parts of catalyst; The raw materials for preparing the composite coupling agent modified kaolin include titanate coupling agent, aluminate coupling agent and nano kaolin, and the weight ratio of the titanate coupling agent, aluminate coupling agent and nano kaolin is (0.3-0.5): (0.1-0.3): (8-10).

[0006] By adopting the above technical scheme, polyester polyol and polyether polyol are used as soft segments in polyurethane, and isocyanate is used as hard segment in polyurethane. Among them, polyester polyol contains a large number of ester groups, has strong polarity, relatively high cohesive energy, and good bonding performance. Polyether polyol contains a large number of ether bonds, which are not easy to hydrolyze, so polyester polyol and polyether polyol are compounded and used, so that the hot melt adhesive in this application has better adhesion and water resistance. There is an -NCO group at the end of the isocyanate molecular chain, and the -NCO group can react with moisture in the air and adsorbed water on the surface of the substrate to form a urea bond, produce cross-linking and curing, and the polar groups can also interact with each other to form strong hydrogen bonds, thereby improving the bonding strength of the hot melt adhesive. Nano-kaolin can form a microscopic barrier structure in the hot melt adhesive, reduce porosity, reduce water penetration, and reduce the erosion of water molecules on the internal structure of the adhesive. Nano-kaolin itself has good chemical stability and is not easy to react with water. It can slow down the chemical degradation of the hot melt adhesive in a humid environment. Under the modification of the composite coupling agent, the compatibility of nano-kaolin in the polyurethane hot melt adhesive is improved, making the internal structure of the hot melt adhesive less likely to be destroyed, thereby improving the hydrolysis stability of the hot melt adhesive.

[0007] Preferably, the titanate coupling agent is at least one of di(dioctyl pyrophosphate)hydroxyacetic acid titanate and dicarboxylic acylethylene diethylene titanate; the aluminate coupling agent is at least one of di(distearic acid glyceryl ester) isopropyl aluminate, di(stearic acid diethylene glycol ester) isopropyl aluminate and di(oleic acid diethylene glycol ester) isopropyl aluminate.

[0008] By adopting the above technical scheme, the alkoxy groups in the titanate coupling agent and the aluminate coupling agent are hydrolyzed and combined with the hydroxyl groups on the surface of kaolin to form an organic active monolayer on the surface of kaolin, which is beneficial to improve the compatibility of kaolin in the molten system. The barrier effect of nano-kaolin is further exerted, making the surface structure of the adhesive layer more compact, and it is difficult for moisture to diffuse into the interior of the adhesive layer, thereby playing a waterproof role and extending the service life of the hot melt adhesive.

[0009] Preferably, the isocyanate is at least one of isophorone diisocyanate, hexamethylene diisocyanate and dicyclohexylmethane diisocyanate.

[0010] By adopting the above technical solution, the hot melt adhesive prepared by using the above aliphatic isocyanate has good durability and light stability, so that the hot melt adhesive is not easy to yellow, has a long service life, and has less impact on the environment.

[0011] Preferably, the polyester polyol is at least one of polyethylene adipate glycol monopropylene glycol ester diol and polyethylene adipate glycol ether diol.

[0012] By adopting the above technical solution, the above polyester polyol and isocyanate have a good combination effect, strong cohesion and crystallization performance, and the prepared hot melt adhesive has a high bonding strength.

[0013] Preferably, the polyether polyol is at least one of polytetramethylene glycol and polyoxypropylene glycol.

[0014] By adopting the above technical solution, the hot melt adhesive prepared by using the above polyether polyol has a relatively low glass transition temperature, good flexibility, good compatibility with isocyanate and polyester polyol, and good processing performance.

[0015] Preferably, the chain extender is at least one of ethylenediamine, N,N-dihydroxy(diisopropyl)aniline, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, sorbitol and diethylaminoethanol.

[0016] By adopting the above technical solution, the chain extender reacts with the functional groups in the polyurethane prepolymer to increase the length of the molecular chain, thereby increasing the cohesive force of the hot melt adhesive and improving the bonding force between the polyurethane and the substrate. At the same time, the chain extender can affect the curing speed of the hot melt adhesive, thereby controlling the transition speed of the hot melt adhesive from liquid to solid.

[0017] Preferably, the antioxidant is at least one of antioxidant 264, antioxidant 1076, and antioxidant 1010.

[0018] By adopting the above technical solution, polyurethane is prone to thermal oxidation degradation and photodegradation under light and heat conditions, and the addition of antioxidants can improve the heat resistance of polyurethane, reduce the problem of polyurethane degradation in a thermal oxidation environment, and improve the stability of polyurethane. The mechanism of action of antioxidants is to reduce the breakage of carbon-hydrogen bonds in the molecular structure and prevent the oxidation reaction from proceeding, thereby achieving an antioxidant effect and helping to maintain the bonding strength and bonding performance of the hot melt adhesive.

[0019] Preferably, the catalyst is an organic zirconium catalyst.

[0020] By adopting the above technical scheme, the organic zirconium catalyst has a significant effect on the -NCO / -OH reaction, stabilizes the intermediates formed during the reaction, reduces the reaction activation energy, and promotes the formation of ion pairs, thereby accelerating the reaction rate, reducing the occurrence of side reactions, and reducing the generation of CO2, thereby reducing the generation of bubbles in the product and improving the mechanical properties of the hot melt adhesive.

[0021] In a second aspect, the present application provides a method for preparing a moisture-curing reactive polyurethane hot melt adhesive for shoes, which adopts the following technical solution: A method for preparing a moisture-curing reactive polyurethane hot melt adhesive for shoes comprises the following steps: The raw materials are weighed according to the component ratio, the polyester polyol and the polyether polyol are mixed under a vacuum environment, stirred and reacted at 120-130° C. for 30-40 minutes, and under the protection of nitrogen, the temperature is lowered to 80-90° C., isocyanate and chain extender are added, and the reaction is carried out for 1-2 hours. Then, composite coupling agent-modified kaolin, chain extender, antioxidant and catalyst are added, and the reaction is carried out at 65-75° C. for 2-3 hours to obtain a moisture-curing reactive polyurethane hot melt adhesive for shoes.

[0022] By adopting the above technical scheme, polyester polyol, polyether polyol and isocyanate are mixed, and then composite coupling agent modified kaolin is added. Under the reinforcing effect of composite coupling agent modified kaolin, the internal structure of the hot melt adhesive is stabilized to improve the water resistance of the hot melt adhesive.

[0023] Preferably, the preparation method of the composite coupling agent modified kaolin is: ① Place kaolin in a NaOH solution, stir at 45-55°C for 2-3h, then wash with deionized water and alcohol alternately, filter under reduced pressure to remove excess water, and dry to obtain pretreated kaolin; ② Mix the titanate coupling agent and the aluminate coupling agent to obtain a composite coupling agent, then add the composite coupling agent to an ethanol solution, adjust the pH to 6.5-7.5, hydrolyze for 1-2 hours to obtain a hydrolyzed coupling agent solution, then add the pretreated kaolin to the hydrolyzed coupling agent solution, stir at 50-60°C for 2-3 hours, then wash alternately with deionized water and alcohol, filter and dry to obtain composite coupling agent modified kaolin.

[0024] By adopting the above technical scheme, the composite coupling agent modified kaolin prepared by the above preparation method has the characteristics of structural stability and strong surface performance, which is conducive to giving full play to the hydrolysis stability of the composite coupling agent modified kaolin.

[0025] This application has the following beneficial effects: In this application, polyester polyol and polyether polyol are used as soft segments in polyurethane, and isocyanate is used as hard segment in polyurethane. Among them, polyester polyol contains a large number of ester groups, has strong polarity, relatively high cohesive energy, and good bonding performance. Polyether polyol contains a large number of ether bonds, which are not easy to hydrolyze, so polyester polyol and polyether polyol are compounded and used, so that the hot melt adhesive in this application has better adhesion and water resistance. There is an -NCO group at the end of the isocyanate molecular chain. The -NCO group can react with moisture in the air and adsorbed water on the surface of the substrate to form a urea bond, produce cross-linking and curing, and the polar groups can also interact with each other to form strong hydrogen bonds, thereby improving the bonding strength of the hot melt adhesive. Nano-kaolin can form a microscopic barrier structure in the hot melt adhesive, reduce porosity, reduce water penetration, and reduce the erosion of water molecules on the internal structure of the adhesive. Nano-kaolin itself has good chemical stability and is not easy to react with water. It can slow down the chemical degradation of the hot melt adhesive in a humid environment. Under the modification of the composite coupling agent, the compatibility of nano-kaolin in the polyurethane hot melt adhesive is improved, making the internal structure of the hot melt adhesive less likely to be destroyed, thereby improving the hydrolysis stability of the hot melt adhesive. DETAILED DESCRIPTION

[0026] Preparation Example Preparation Example 1 Preparation method of composite coupling agent modified kaolin: ① Place 8 kg of nano-kaolin in a NaOH solution, stir at 45°C for 2 h, remove excess water by vacuum filtration, and dry to obtain pretreated kaolin; ② Mix 0.3 kg of di(dioctyl pyrophosphate)hydroxyacetic acid titanate and 0.1 kg of di(distearic acid glyceryl)aluminate isopropyl to obtain a composite coupling agent, then add the composite coupling agent to an ethanol solution, adjust the pH to 6.5, hydrolyze for 1 hour to obtain a hydrolyzed coupling agent solution, then add the pretreated kaolin to the hydrolyzed coupling agent solution, stir at 50°C for 2 hours, filter and dry to obtain composite coupling agent modified kaolin.

[0027] Preparation Example 2 Preparation method of composite coupling agent modified kaolin: ① Place 9 kg of nano-kaolin in a NaOH solution, stir at 50°C for 2.5 h, remove excess water by vacuum filtration, and dry to obtain pretreated kaolin; ② Mix 0.4 kg of dicarboxylic acyl ethylene dititanate and 0.2 kg of isopropyl di(stearate glycol)aluminate to obtain a composite coupling agent, then add the composite coupling agent to an ethanol solution, adjust the pH to 7.0, hydrolyze for 1.5 h to obtain a hydrolyzed coupling agent solution, then add the pretreated kaolin to the hydrolyzed coupling agent solution, stir at 55 ° C for 2.5 h, filter and dry to obtain composite coupling agent modified kaolin.

[0028] Preparation Example 3 Preparation method of composite coupling agent modified kaolin: ① Place 10 kg of nano-kaolin in a NaOH solution, stir at 50°C for 3 h, remove excess water by vacuum filtration, and dry to obtain pretreated kaolin; ② Mix 0.5 kg of di(dioctyl pyrophosphate)hydroxyacetic acid titanate and 0.3 kg of di(diethylene glycol oleate) isopropyl aluminate to obtain a composite coupling agent, then add the composite coupling agent to an ethanol solution, adjust the pH to 7.5, hydrolyze for 2 hours to obtain a hydrolyzed coupling agent solution, then add the pretreated kaolin to the hydrolyzed coupling agent solution, stir at 60°C for 3 hours, filter and dry to obtain composite coupling agent modified kaolin. Example

[0029] Example 1 A moisture-curing reactive polyurethane hot melt adhesive for shoes comprises 20 kg of polyethylene adipate glycol monopropylene glycol ester diol (molecular weight 2000), 40 kg of polytetramethylene ether diol (molecular weight 2000), 25 kg of isophorone diisocyanate, 10 kg of composite coupling agent modified kaolin (prepared in Preparation Example 1), 2 kg of 1,4-butanediol, 0.5 kg of antioxidant 1076, and 0.02 kg of tetrabutyl zirconate.

[0030] The method for preparing the moisture-curing reactive polyurethane hot melt adhesive for shoes in this embodiment comprises the following steps: The raw materials were weighed according to the component ratio, polyethylene adipate glycol monopropylene glycol ester diol and polytetramethylene ether diol were mixed, and vacuum was drawn. The mixture was stirred and reacted at 120°C for 30 minutes. Under the protection of nitrogen, the temperature was lowered to 80°C, and isophorone diisocyanate and 1,4-butanediol were added. The mixture was reacted for 1 hour. Then, composite coupling agent modified kaolin, antioxidant 1076 and tetrabutyl zirconate were added. The mixture was reacted at 65°C for 2 hours to obtain a moisture-curing reactive polyurethane hot melt adhesive for shoes.

[0031] Example 2 A moisture-curing reactive polyurethane hot melt adhesive for shoes comprises 25kg of polyethylene adipate glycol (molecular weight 3000), 45kg of polyoxypropylene glycol (molecular weight 2000), 30kg of hexamethylene diisocyanate, 15kg of composite coupling agent modified kaolin (prepared in Preparation Example 2), 3kg of N,N-dihydroxy (diisopropyl) aniline, 0.6kg of antioxidant 1010, and 0.03kg of tetrabutyl zirconate.

[0032] The method for preparing the moisture-curing reactive polyurethane hot melt adhesive for shoes in this embodiment comprises the following steps: The raw materials were weighed according to the component ratio, poly(ethylene glycol adipate) glycol and poly(propylene oxide) glycol were mixed, and vacuum was drawn. The mixture was stirred and reacted at 125°C for 35 minutes. Under the protection of nitrogen, the mixture was cooled to 85°C, hexamethylene diisocyanate and N, N-dihydroxy (diisopropyl) aniline were added, and the reaction was carried out for 1.5 hours. Subsequently, composite coupling agent-modified kaolin, antioxidant 1010 and tetrabutyl zirconate were added, and the mixture was reacted at 70°C for 2.5 hours to obtain a moisture-curing reactive polyurethane hot melt adhesive for shoes.

[0033] Example 3 A moisture-curing reactive polyurethane hot melt adhesive for shoes comprises 30 kg of polyethylene adipate glycol (molecular weight 2000), 50 kg of polytetramethylene ether glycol (molecular weight 3000), 35 kg of dicyclohexylmethane diisocyanate, 20 kg of composite coupling agent modified kaolin (prepared in Preparation Example 3), 4 kg of ethylenediamine, 0.7 kg of antioxidant 264, and 0.04 kg of tetrabutyl zirconate.

[0034] The method for preparing the moisture-curing reactive polyurethane hot melt adhesive for shoes in this embodiment comprises the following steps: The raw materials were weighed according to the component ratio, poly(ethylene glycol adipate) diol and polytetramethylene glycol ether) diol were mixed, and vacuum was drawn. The mixture was stirred and reacted at 130°C for 40 minutes. Under the protection of nitrogen, the temperature was lowered to 90°C, dicyclohexylmethane diisocyanate and ethylenediamine were added, and the mixture was reacted for 2 hours. Subsequently, composite coupling agent modified kaolin, antioxidant 264 and tetrabutyl zirconate were added, and the mixture was reacted at 75°C for 3 hours to obtain a moisture-curing reactive polyurethane hot melt adhesive for shoes.

[0035] Example 4 A moisture-curing reactive polyurethane hot melt adhesive for shoes, which differs from Example 1 in that isophorone diisocyanate is replaced by an equal amount of diphenylmethane diisocyanate.

[0036] Comparative Example Comparative Example 1 A moisture-curing reactive polyurethane hot melt adhesive for shoes, which differs from Example 1 in that the composite coupling agent-modified kaolin is replaced by an equal amount of nano-kaolin.

[0037] Comparative Example 2 A moisture-curing reactive polyurethane hot melt adhesive for shoes, which differs from Example 1 in that the composite coupling agent-modified kaolin is replaced by an equal amount of titanate coupling agent-modified kaolin.

[0038] Comparative Example 3 A moisture-curing reactive polyurethane hot melt adhesive for shoes, which differs from Example 1 in that the composite coupling agent-modified kaolin is replaced by an equal amount of aluminate coupling agent-modified kaolin.

[0039] Comparative Example 4 A moisture-curing reactive polyurethane hot melt adhesive for shoes, which differs from Example 1 in that no composite coupling agent-modified kaolin is added.

[0040] Performance testing 1. Water resistance test: The samples bonded with the hot melt adhesive prepared in Examples 1-4 and Comparative Examples 1-4 were aged in air, hot water (80°C) and cold water (30°C) for 7 days, respectively, and then dried for 1 day in an environment of 25% and 50% relative humidity. Referring to QJ 1634A-96 "Adhesive Compression Shear Strength Test Method", the compression shear strength test of the bonded samples was carried out. The test results are shown in Table 1.

[0041] 2. Water absorption test: The samples bonded with the hot melt adhesive prepared in Examples 1-4 and Comparative Examples 1-4 were placed in an oven at 70°C and fully dried to constant weight, and their initial mass was recorded as m0. The samples were then immersed in deionized water at room temperature for 24 hours. After being taken out, the surface moisture was quickly absorbed with a paper towel and weighed. The mass was recorded as m1. The water absorption (η) of the samples after immersion for 24 hours was calculated according to formula (1): Water absorption rate can characterize the ability of water molecules to enter the adhesive. The greater the water absorption rate, the easier it is for water to erode the adhesive layer.

[0042] 3. Melt viscosity test: Refer to standard HG / T3660-1999 to measure the melt viscosity of the sample. Place the sealed hot melt adhesive sample in an oven and heat it for about 30 minutes until the sample becomes a molten fluid. Then, quickly pour it into the sleeve of the SNB-2 rotor viscometer, set the temperature and maintain it for about 20 minutes to make the internal temperature of the glue sample uniform, and finally measure the constant temperature melt viscosity of PURHMA.

[0043] Table 1 According to the comparison between Example 1 and Comparative Example 1 and the data in Table 1, it can be seen that when nano-kaolin is added directly to the raw material without modification, the cross-linked structure formed is not stable enough due to the poor compatibility of nano-kaolin with the molten system, making the hot melt adhesive prone to hydrolysis. On the contrary, by modifying nano-kaolin with a composite coupling agent, the compatibility of nano-kaolin in the polyurethane hot melt adhesive can be improved, making the internal structure of the hot melt adhesive less likely to be destroyed, thereby improving the hydrolysis stability of the hot melt adhesive.

[0044] According to the comparison between Example 1 and Comparative Examples 2-3 and the data in Table 1, it can be seen that the modification effect of nano-kaolin using a single coupling agent is not obvious. When the nano-kaolin is modified using a composite coupling agent, an organic active monolayer can be formed on the surface of the kaolin, which improves the compatibility of the nano-kaolin in the molten system, can form a microscopic barrier structure in the hot melt adhesive, reduce porosity, reduce water penetration, and reduce the erosion of water molecules on the internal structure of the adhesive, thereby improving the water resistance of the hot melt adhesive. At the same time, it also has a certain role in promoting the improvement of the bonding performance of the hot melt adhesive.

[0045] According to the comparison between Example 1 and Comparative Example 4 and the data in Table 1, it can be seen that when the composite coupling agent is not added to modify the kaolin, the water resistance of the hot melt adhesive is poor. On the contrary, after adding the composite coupling agent to modify the kaolin, the hydrolysis stability of the hot melt adhesive can be improved. Since the nano-kaolin forms a physical barrier in the hot melt adhesive, it slows down the penetration of water molecules and can also improve the stability of the cross-linked network structure of the hot melt adhesive and increase the bonding performance of the hot melt adhesive.

[0046] According to the comparison between Example 1 and Example 4 and the data in Table 1, it can be seen that compared with aliphatic isocyanates, aromatic isocyanates have poorer hydrolysis resistance, especially in a humid environment. Aliphatic isocyanates do not contain a benzene ring structure and thus exhibit better chemical stability.

[0047] This specific implementation manner 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 specific implementation manner as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A moisture-curing reactive polyurethane hot melt adhesive for shoes, characterized in that: The invention is prepared from the following raw materials by weight: 20-30 parts of polyester polyol, 40-50 parts of polyether polyol, 25-35 parts of isocyanate, 10-20 parts of composite coupling agent modified kaolin, 2-4 parts of chain extender, 0.5-0.7 parts of antioxidant, and 0.02-0.04 parts of catalyst; The raw materials for preparing the composite coupling agent modified kaolin include titanate coupling agent, aluminate coupling agent and nano kaolin, and the weight ratio of the titanate coupling agent, aluminate coupling agent and nano kaolin is (0.3-0.5): (0.1-0.3): (8-10).

2. A moisture-curing reactive polyurethane hot melt adhesive for shoes according to claim 1, characterized in that: The titanate coupling agent is at least one of di(dioctyl pyrophosphate)hydroxyacetic acid titanate and dicarboxylic acylethylene diethylene titanate; the aluminate coupling agent is at least one of di(distearic acid glyceryl ester) isopropyl aluminate, di(stearic acid diethylene glycol ester) isopropyl aluminate and di(oleic acid diethylene glycol ester) isopropyl aluminate.

3. A moisture-curing reactive polyurethane hot melt adhesive for shoes according to claim 1, characterized in that: The isocyanate is at least one of isophorone diisocyanate, hexamethylene diisocyanate and dicyclohexylmethane diisocyanate.

4. The moisture-curing reactive polyurethane hot melt adhesive for shoes according to claim 1, characterized in that: The polyester polyol is at least one of polyethylene adipate glycol monopropylene glycol ester diol and polyethylene adipate glycol ether diol.

5. The moisture-curing reactive polyurethane hot melt adhesive for shoes according to claim 1, characterized in that: The polyether polyol is at least one of polytetramethylene glycol and polyoxypropylene glycol.

6. The moisture-curing reactive polyurethane hot melt adhesive for shoes according to claim 1, characterized in that: The chain extender is at least one of ethylenediamine, N,N-dihydroxy (diisopropyl) aniline, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, sorbitol and diethylaminoethanol.

7. The moisture-curing reactive polyurethane hot melt adhesive for shoes according to claim 1, characterized in that: The antioxidant is at least one of antioxidant 264, antioxidant 1076, and antioxidant 1010.

8. The moisture-curing reactive polyurethane hot melt adhesive for shoes according to claim 1, characterized in that: The catalyst is an organic zirconium catalyst.

9. A method for preparing a moisture-curing reactive polyurethane hot melt adhesive for shoes according to any one of claims 1 to 8, characterized in that: The following steps are involved: The raw materials are weighed according to the component ratio, the polyester polyol and the polyether polyol are mixed under a vacuum environment, stirred and reacted at 120-130° C. for 30-40 minutes, and under the protection of nitrogen, the temperature is lowered to 80-90° C., isocyanate and chain extender are added, and the reaction is carried out for 1-2 hours. Then, composite coupling agent-modified kaolin, chain extender, antioxidant and catalyst are added, and the reaction is carried out at 65-75° C. for 2-3 hours to obtain a moisture-curing reactive polyurethane hot melt adhesive for shoes.

10. The method for preparing a moisture-curing reactive polyurethane hot melt adhesive for shoes according to claim 9, characterized in that: The preparation method of the composite coupling agent modified kaolin is: ① Place kaolin in NaOH solution, stir at 45-55°C for 2-3h, remove excess water by vacuum filtration, and dry to obtain pretreated kaolin; ② Mix the titanate coupling agent and the aluminate coupling agent to obtain a composite coupling agent, then add the composite coupling agent to an ethanol solution, adjust the pH to 6.5-7.5, hydrolyze for 1-2 hours to obtain a hydrolyzed coupling agent solution, then add the pretreated kaolin to the hydrolyzed coupling agent solution, stir at 50-60°C for 2-3 hours, filter and dry to obtain composite coupling agent modified kaolin.

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