The application discloses a water-based polyurethane emulsion for direct foaming of sports shoe leather, and relates to the field of sports shoe leather materials.

Abstract

This invention discloses an aqueous polyurethane emulsion for direct coating and foaming of sports shoe leather. Its raw materials include: diisocyanate, polyol compound, chain extender, neutralizing agent, catalyst, and water. The chain extender includes: a Y-shaped single-terminated dihydroxyl polyether, a carboxyl-containing hydrophilic chain extender, a small molecule diol chain extender, an amine chain extender, and N,N-di(2-hydroxyethyl)-3-aminopropionylglycine. This invention also discloses a method for preparing the above-mentioned aqueous polyurethane emulsion for direct coating and foaming of sports shoe leather. This invention also discloses a sports shoe leather comprising: nonwoven fabric and a foaming emulsion, wherein the raw materials of the foaming emulsion include: a thickener, a foaming agent, a curing agent, and the above-mentioned aqueous polyurethane emulsion. This invention also discloses a method for preparing the above-mentioned sports shoe leather. This invention enables sports shoe leather to not only have good peel strength and room temperature folding resistance, but also to avoid drying cracking during production and processing.

Description

Technical Field

[0001] This invention relates to the field of microfiber leather technology, and more particularly to a water-based polyurethane emulsion for direct coating foaming of sports shoe leather. Background Technology

[0002] Since the 20th century, synthetic leather products have been widely used in civilian fields such as sofas, bags, shoe materials, electronic packaging, and home building materials due to their excellent physical and mechanical properties and colorful appearance and patterns. However, traditional synthetic leather products still use large amounts of toxic and harmful solvents such as DMF, methyl ethyl ketone, and ethyl acetate.

[0003] Against the backdrop of environmental protection and green manufacturing, the synthetic leather industry has also ushered in a new generation of environmentally friendly synthetic leather products. Currently, synthetic leather for sofas and furniture is produced using solvent-free methods, resulting in superior performance, low-temperature properties, and environmental friendliness. Leather for bags and clothing has lower material property requirements and is generally produced using water-based polyurethane foaming processes, achieving green and environmentally friendly production as well. Currently, only the sports shoe leather sector continues to use solvent-based polyurethane resins and wet processing techniques.

[0004] With increasing environmental concerns, solvent-free methods have been used to produce athletic shoe leather, but these methods suffer from issues related to later stages such as glue application and injection molding delamination. While waterborne polyurethane is used to produce athletic shoe leather, its lower molecular weight and strength make it difficult to achieve breakthroughs in peel strength and room-temperature flexural strength. Furthermore, the high coating thickness of athletic shoe leather makes it prone to cracking during drying. Therefore, the environmental friendliness of athletic shoe leather has progressed slowly. There is a need for an environmentally friendly waterborne polyurethane emulsion that meets the requirements for athletic shoe leather. Summary of the Invention

[0005] Based on the technical problems existing in the background technology, the present invention proposes a water-based polyurethane emulsion for direct coating foaming of sports shoe leather. The water-based polyurethane emulsion of the present invention is used to produce sports shoe leather using a direct coating foaming process, which makes the sports shoe leather not only have good peel strength and room temperature folding resistance, but also less prone to drying cracking during the production and processing.

[0006] This invention proposes an aqueous polyurethane emulsion for direct coating foaming of sports shoe leather, the raw materials of which include: diisocyanate, polyol compound, chain extender, neutralizer, catalyst and water;

[0007] Among them, chain extenders include: single-terminal dihydroxy polyethers with Y-shaped structures, hydrophilic chain extenders containing carboxyl groups, small molecule diol chain extenders, amine chain extenders, and N,N-di(2-hydroxyethyl)-3-aminopropionylglycine.

[0008] Preferably, the Y-type single-ended dihydroxy polyether is Ymer N120.

[0009] The aforementioned Y-shaped single-ended dihydroxyl polyether is a nonionic hydrophilic chain extender.

[0010] The aforementioned Ymer N120 was purchased from the Swedish Pastor Group.

[0011] Preferably, the carboxyl-containing hydrophilic chain extender is one or both of dimethylolpropionic acid and dihydroxybutyric acid.

[0012] Preferably, the amine chain extender is one or more of ethylenediamine, isophorone diamine, diethylenetriamine, and hydroxyethyl ethylenediamine.

[0013] Preferably, the amine chain extender is a mixture of ethylenediamine and hydroxyethyl ethylenediamine in a weight ratio of 3-4:1.

[0014] Preferably, the polyol compound is one or both of polytetrahydrofurandiol and adipic acid-based polyester polyols.

[0015] Preferably, the polyol compound is a mixture of polytetrahydrofuran diol and adipic acid-based polyester polyol in a weight ratio of 2-2.2:1.

[0016] Preferably, the diisocyanate is an aliphatic diisocyanate.

[0017] Preferably, the small molecule diol chain extender is one or more of ethylene glycol, 1,4-butanediol, and neopentyl glycol.

[0018] Preferably, the neutralizing agent is one or both of triethylamine and triethanolamine.

[0019] Preferably, the weight ratio of the Y-shaped single-ended dihydroxy polyether to the carboxyl-containing hydrophilic chain extender is 0.5-0.9:1.

[0020] Preferably, the weight ratio of the carboxyl-containing hydrophilic chain extender, amine chain extender, N,N-bis(2-hydroxyethyl)-3-aminopropionylglycine amide, and small molecule diol chain extender is 1:0.6-0.9:0.14-0.2:0.3-0.5.

[0021] Preferably, the weight ratio of diisocyanate to polyol compound is 6-9:17-27.

[0022] Preferably, the weight ratio of diisocyanate to chain extender is 6-9:1-2.1.

[0023] Preferably, the weight ratio of diisocyanate to catalyst is 6-9:0.002-0.005.

[0024] Preferably, the weight ratio of diisocyanate to water is 6-9:30-48.

[0025] Preferably, the weight ratio of diisocyanate to neutralizing agent is 6-9:0.2-0.5.

[0026] The raw materials for the above-mentioned water-based polyurethane emulsion for direct coating foaming of sports shoe leather may also include: antioxidants, etc., and the weight ratio of diisocyanate to antioxidant is 6-9:0.016-0.03.

[0027] The aforementioned aliphatic diisocyanate may be one or more of isophorone diisocyanate, hexamethylene diisocyanate, and dicyclohexylmethane diisocyanate. The aforementioned adipic acid-based polyester polyol may be adipic acid neopentyl glycol polyester polyol, etc.

[0028] The catalyst mentioned above can be the organobismuth catalyst MB20; the antioxidant mentioned above can be one or two of pentaerythritol tetrakis(β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) and 2,2'-methylenebis(4-methyl-6-tert-butylphenol).

[0029] The aforementioned N,N-di(2-hydroxyethyl)-3-aminopropionylglycine can be purchased commercially or prepared by a Michael addition reaction of acryloylglycine and diethanolamine. The specific preparation steps include: dissolving acryloylglycine in a mixed solvent of water and methanol, adding a methanol solution of diethanolamine, stirring at 35-45°C for 20-30 hours, removing water and methanol, washing the remaining solid with acetone until the pH is neutral, and drying to obtain N,N-di(2-hydroxyethyl)-3-aminopropionylglycine. Preferably, the molar ratio of acryloylglycine to diethanolamine is 1-1.2:1.

[0030] This invention also proposes a method for preparing the above-mentioned waterborne polyurethane emulsion for direct coating foaming of sports shoe leather, comprising the following steps: in an inert gas atmosphere, a polyol compound, a Y-shaped single-terminated dihydroxy polyether, a diisocyanate, and a catalyst are mixed and reacted once; then a hydrophilic chain extender containing a carboxyl group, a small molecule diol chain extender, and N,N-di(2-hydroxyethyl)-3-aminopropionylglycine are added for a second reaction; an organic solvent is added to reduce viscosity; a neutralizing agent is added for a neutralization reaction; water is added for emulsification; then an amine chain extender is added for a third reaction; the organic solvent is removed to obtain the waterborne polyurethane emulsion for direct coating foaming of sports shoe leather.

[0031] The diisocyanates, polyol compounds, chain extenders, catalysts, neutralizers, and antioxidants mentioned above are all dried and dehydrated before use.

[0032] Preferably, the reaction is carried out at 90-95℃ for 1.5-2.5 hours.

[0033] Preferably, the secondary reaction is carried out at 60-65℃ for 1.5-2.5 hours.

[0034] Preferably, the neutralization reaction is carried out at 20-40°C for 5-15 minutes.

[0035] Preferably, the reaction is carried out three times at 20-40℃ for 1.5-2.5 hours.

[0036] The present invention also proposes a sports shoe leather, comprising: non-woven fabric and foaming emulsion, wherein the raw materials of the foaming emulsion include: thickener, foaming agent, curing agent and the above-mentioned waterborne polyurethane emulsion.

[0037] Preferably, the weight ratio of the waterborne polyurethane emulsion, thickener, foaming agent, and curing agent is 100:0.3-0.5:3-5:0.8-1.2.

[0038] Preferably, the viscosity of the foaming emulsion at 25°C is 15,000-20,000 CPS.

[0039] Preferably, the curing agent is one or more of polymeric MDI curing agents, polymeric IPDI curing agents, and polymeric HDI curing agents.

[0040] The aforementioned foaming emulsion may also contain fillers, color pastes, etc.; the fillers may be kaolin, etc.; the weight ratio of waterborne polyurethane emulsion to filler may be 100:4-6; the amount of color paste added may be adjusted according to the color requirements of sports shoe leather.

[0041] The thickeners mentioned above can be associative waterborne polyurethane thickeners, etc., and the foaming agents can be stearate-type foaming agents, etc.

[0042] The present invention also proposes a method for preparing the above-mentioned sports shoe leather, comprising the following steps: mixing the raw materials of the foaming emulsion, coating it on the surface of a non-woven fabric, curing and drying it to obtain sports shoe leather.

[0043] Preferably, the curing and drying procedure is as follows: keep warm at 85-95℃ for 4-6 minutes, then keep warm at 105-115℃ for 4-6 minutes, and finally dry at 120-140℃.

[0044] 1. This invention uses a Y-shaped single-ended dihydroxyl polyether and a carboxyl-containing hydrophilic chain extender in combination. When the weight ratio of the two is 0.5-0.9:1, the problem of cracking in the emulsion during the drying process can be avoided. In addition, an appropriate amount of N,N-di(2-hydroxyethyl)-3-aminopropionylglycine is added as a chain extender to introduce aminopropionylglycine groups, which can form hydrogen bonds between polyurethane molecular chains, improve the crack resistance and adhesion of polyurethane, and avoid problems such as cracking, degumming, and low peel strength in sports shoe leather. Furthermore, the combination of the Y-shaped single-ended dihydroxyl polyether, the carboxyl-containing hydrophilic chain extender, and N,N-di(2-hydroxyethyl)-3-aminopropionylglycine can increase the initial drying temperature and relax the requirements of production operation during the preparation of sports shoe leather.

[0045] 2. This invention uses an amine chain extender with hydroxyl groups in combination with N,N-di(2-hydroxyethyl)-3-aminopropionylglycine, so that the polyurethane molecular chain contains a small amount of reactive hydroxyl and amino groups, which can react with the curing agent in the foaming emulsion to increase the crosslinking density of the polyurethane, thereby significantly improving the peel strength and room temperature folding resistance of the sports shoe leather; and the aminopropionylglycine group in N,N-di(2-hydroxyethyl)-3-aminopropionylglycine can react with the curing agent in the foaming emulsion to form urea groups, further improving the strength of hydrogen bonding, and further improving the crack resistance, peel strength and room temperature folding resistance.

[0046] The waterborne polyurethane emulsion described in this invention is used in the production of sports shoe leather using a direct coating foaming process. This results in sports shoe leather that not only has good peel strength and room temperature folding resistance, but also is less prone to drying cracking during the production and processing. Detailed Implementation

[0047] The technical solution of the present invention will now be described in detail through specific embodiments.

[0048] The raw material information is shown in Table 1.

[0049] Table 1 Raw Material Information

[0050]

[0051] Example 1

[0052] A water-based polyurethane emulsion for direct coating foaming of sports shoe leather, comprising the following raw materials by weight: HMDI 78g, IPDI 20g, PTMG-2000 200g, XCPP-2000N 95g, Ymer N120 5g, DMPA 7g, ethylene glycol 3g, ethylenediamine 4.2g, hydroxyethyl ethylenediamine 1.2g, N,N-di(2-hydroxyethyl)-3-aminopropionylglycine 1g, organic bismuth catalyst MB20 0.05g, antioxidant I-1010 0.3g, neutralizing agent triethylamine 5.27g, and deionized water 520g.

[0053] The preparation method of the above-mentioned water-based polyurethane emulsion for direct coating foaming of sports shoe leather includes the following steps:

[0054] Weigh each raw material according to the weight parts, add PTMG-2000, XCPP-2000N, Ymer N120 and antioxidant I-1010 into the reaction flask and dehydrate under reduced pressure at 110-120℃ for 1-2 hours, then cool to 50℃, and then add HMDI and IPDI under nitrogen protection, and carry out a single reaction at 90-95℃ for 2 hours. Organic bismuth catalyst MB20 is added during the reaction process.

[0055] Then, DMPA, ethylene glycol, and N,N-di(2-hydroxyethyl)-3-aminopropionylglycine were added, and a second reaction was carried out at 60-65℃ for 2 hours. After the time was up, a sample was taken, and the NCO% was determined by di-n-butylamine titration. When the NCO% was lower than the theoretical value, the reaction was stopped, and the temperature was lowered to 30-40℃. Then, 360g of acetone was added to reduce viscosity, and triethylamine was added as a neutralizing agent. The neutralization reaction was carried out at 30-40℃ for 10 minutes. Then, deionized water was added under high-speed stirring at 1000-1500rpm to emulsify and disperse the mixture to obtain an emulsion.

[0056] After adding ethylenediamine and hydroxyethyl ethylenediamine dropwise to the emulsion, the mixture was stirred at 30-40℃ for three reactions over 2 hours. Then, acetone was removed by vacuum distillation to obtain an aqueous polyurethane emulsion for direct coating foaming of sports shoe leather.

[0057] Example 2

[0058] A water-based polyurethane emulsion for direct coating foaming of sports shoe leather, comprising the following raw materials by weight: HMDI 78g, IPDI 20g, PTMG-2000 200g, XCPP-2000N 95g, Ymer N120 3.2g, DMPA 6g, ethylene glycol 3g, ethylenediamine 4.2g, hydroxyethyl ethylenediamine 1.2g, N,N-di(2-hydroxyethyl)-3-aminopropionylglycine 1g, organic bismuth catalyst MB20 0.05g, antioxidant I-1010 0.3g, neutralizing agent triethylamine 4.52g, and deionized water 520g.

[0059] The preparation method of the above-mentioned water-based polyurethane emulsion for direct coating foaming of sports shoe leather is the same as that in Example 1.

[0060] Example 3

[0061] A water-based polyurethane emulsion for direct coating foaming of sports shoe leather, comprising the following raw materials by weight: HMDI 88g, IPDI 15g, PTMG-2000 200g, XCPP-2000N 95g, Ymer N120 5.6g, DMPA 8g, ethylene glycol 3g, ethylenediamine 4.2g, hydroxyethyl ethylenediamine 1.2g, N,N-di(2-hydroxyethyl)-3-aminopropionylglycine 1.6g, organic bismuth catalyst MB20 0.05g, antioxidant I-1010 0.3g, neutralizing agent triethylamine 4.52g, and deionized water 520g.

[0062] The preparation method of the above-mentioned water-based polyurethane emulsion for direct coating foaming of sports shoe leather is the same as that in Example 1.

[0063] Comparative Example 1

[0064] Ymer N120 was 3g (i.e., the weight ratio of Y-shaped single-ended dihydroxy polyether to carboxyl-containing hydrophilic chain extender was 0.4:1), and other aspects were the same as in Example 1.

[0065] Comparative Example 2

[0066] Ymer N120 was 6g (i.e., the weight ratio of Y-shaped single-ended dihydroxy polyether to carboxyl-containing hydrophilic chain extender was 1:1), and other aspects were the same as in Example 2.

[0067] Comparative Example 3

[0068] It does not contain hydroxyethyl ethylenediamine, and is otherwise the same as in Example 2.

[0069] Comparative Example 4

[0070] It does not contain N,N-di(2-hydroxyethyl)-3-aminopropionylglycine, otherwise it is the same as in Example 2.

[0071] Comparative Example 5

[0072] It does not contain hydroxyethyl ethylenediamine and N,N-di(2-hydroxyethyl)-3-aminopropionylglycine, otherwise it is the same as in Example 2.

[0073] Examples 1-3 and Comparative Examples 1-5, as well as a commercially available waterborne polyurethane foaming emulsion for sports shoe leather (Wanhua Chemical waterborne polyurethane foaming emulsion, solid content 45%, referred to as Comparative Example 6), were prepared into a foaming emulsion using the same method. The viscosity of the foaming emulsion at 25°C was 15,000-20,000 CPS. The foaming emulsion was then coated onto the surface of a nonwoven fabric with a coating gap controlled at 130 mils. The fabric was then kept at 90°C for 4-6 minutes, then at 110°C for 5 minutes, and finally dried at 130°C to obtain the sports shoe leather.

[0074] The formula for the foaming emulsion is as follows: 100 parts of waterborne polyurethane emulsion, 0.4 parts of thickener, 4 parts of foaming agent, 5 parts of kaolin, 1 part of polymeric MDI curing agent, and 1 part of color paste.

[0075] According to the synthetic leather industry standard QB / T 1646-2007, the peel strength and room temperature flexural strength of the obtained sports shoe leather were tested. The test results are shown in Table 2.

[0076] Table 2 Test Results

[0077]

[0078] As can be seen from Table 2, the waterborne polyurethane emulsion described in this invention is used to produce sports shoe leather using a direct coating foaming process. It is not prone to cracking during high-temperature drying, has a peel strength greater than 100N / 3CM, and also has good folding resistance at room temperature, exceeding 100,000 cycles, thus meeting the requirements for sports shoe leather.

[0079] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A water-based polyurethane emulsion for direct coating and foaming of sports shoe leather, characterized in that, Its raw materials include: diisocyanate, polyol compound, chain extender, neutralizer, catalyst and water; Among them, chain extenders include: single-terminated dihydroxy polyethers with Y-shaped structures, hydrophilic chain extenders containing carboxyl groups, small molecule diol chain extenders, amine chain extenders, and N,N-di(2-hydroxyethyl)-3-aminopropionylglycine. The weight ratio of Y-shaped single-ended dihydroxyl polyether to carboxyl-containing hydrophilic chain extender is 0.5-0.9:1; Amine chain extenders are mixtures of ethylenediamine and hydroxyethyl ethylenediamine in a weight ratio of 3-4:1; The polyol compound is one or both of polytetrahydrofurandiol and adipic acid-based polyester polyols; The weight ratio of diisocyanate to polyol compound is 6-9:17-27; The weight ratio of diisocyanate to chain extender is 6-9:1-2.

1.

2. The water-based polyurethane emulsion for direct coating and foaming of sports shoe leather according to claim 1, characterized in that, The Y-type single-ended dihydroxy polyether is Ymer N120.

3. The water-based polyurethane emulsion for direct coating and foaming of sports shoe leather according to claim 1, characterized in that, The carboxyl-containing hydrophilic chain extender is one or both of dimethylolpropionic acid and dihydroxybutyric acid.

4. The water-based polyurethane emulsion for direct coating and foaming of sports shoe leather according to claim 1, characterized in that, The polyol compound is a mixture of polytetrahydrofuran diol and adipic acid-based polyester polyol in a weight ratio of 2-2.2:

1.

5. The water-based polyurethane emulsion for direct coating and foaming of sports shoe leather according to claim 1, characterized in that, Diisocyanates are aliphatic diisocyanates.

6. The water-based polyurethane emulsion for direct coating and foaming of sports shoe leather according to claim 1, characterized in that, Small molecule diol chain extenders are one or more of ethylene glycol, 1,4-butanediol, and neopentyl glycol.

7. The water-based polyurethane emulsion for direct coating and foaming of sports shoe leather according to claim 1, characterized in that, The neutralizing agent is one or both of triethylamine and triethanolamine.

8. The water-based polyurethane emulsion for direct coating and foaming of sports shoe leather according to claim 1, characterized in that, The weight ratio of carboxyl-containing hydrophilic chain extenders, amine chain extenders, N,N-bis(2-hydroxyethyl)-3-aminopropionylglycine amide, and small molecule diol chain extenders is 1:0.6-0.9:0.14-0.2:0.3-0.

5.

9. The water-based polyurethane emulsion for direct coating and foaming of sports shoe leather according to claim 1, characterized in that, The weight ratio of diisocyanate to catalyst is 6-9:0.002-0.

005.

10. The waterborne polyurethane emulsion for direct coating and foaming of sports shoe leather according to claim 1, characterized in that, The weight ratio of diisocyanate to water is 6-9:30-48.

11. The water-based polyurethane emulsion for direct coating and foaming of sports shoe leather according to claim 1, characterized in that, The weight ratio of diisocyanate to neutralizing agent is 6-9:0.2-0.

5.

12. A method for preparing an aqueous polyurethane emulsion for direct coating foaming of sports shoe leather as described in any one of claims 1-11, characterized in that, The process includes the following steps: In an inert gas atmosphere, a polyol compound, a Y-shaped single-terminated dihydroxy polyether, a diisocyanate, and a catalyst are mixed and reacted once. Then, a hydrophilic chain extender containing carboxyl groups, a small molecule diol chain extender, and N,N-di(2-hydroxyethyl)-3-aminopropionylglycine are added for a second reaction. An organic solvent is added to reduce viscosity, a neutralizing agent is added for neutralization, water is added for emulsification, and an amine chain extender is added for a third reaction. The organic solvent is then removed to obtain an aqueous polyurethane emulsion for direct coating foaming of sports shoe leather.

13. The method for preparing the water-based polyurethane emulsion for direct coating foaming of sports shoe leather according to claim 12, characterized in that, The reaction is carried out at 90-95℃ for 1.5-2.5 hours.

14. The method for preparing the water-based polyurethane emulsion for direct coating foaming of sports shoe leather according to claim 12, characterized in that, The secondary reaction was carried out at 60-65℃ for 1.5-2.5 hours.

15. The method for preparing the water-based polyurethane emulsion for direct coating foaming of sports shoe leather according to claim 12, characterized in that, The neutralization reaction is carried out at 20-40℃ for 5-15 minutes.

16. The method for preparing the water-based polyurethane emulsion for direct coating foaming of sports shoe leather according to claim 12, characterized in that, The reaction was carried out three times at 20-40℃ for 1.5-2.5 hours.

17. A type of sports shoe leather, characterized in that, include: Nonwoven fabric and foamed emulsion, wherein the raw materials of the foamed emulsion include: thickener, foaming agent, curing agent and waterborne polyurethane emulsion as described in any one of claims 1-11; The foaming agent is a stearate type foaming agent.

18. The sports shoe leather according to claim 17, characterized in that, The weight ratio of waterborne polyurethane emulsion, thickener, foaming agent, and curing agent is 100:0.3-0.5:3-5:0.8-1.

2.

19. The sports shoe leather according to claim 17, characterized in that, The viscosity of the foamed emulsion at 25°C is 15,000-20,000 CPS.

20. The sports shoe leather according to claim 17, characterized in that, The curing agent is one or more of the following: polymeric MDI curing agent, polymeric IPDI curing agent, and polymeric HDI curing agent.

21. A method for preparing sports shoe leather as described in any one of claims 17-20, characterized in that, The process includes the following steps: mixing the raw materials of the foaming emulsion, coating it onto the surface of the nonwoven fabric, curing and drying it to obtain sports shoe leather.

22. The method for preparing sports shoe leather according to claim 21, characterized in that, The curing and drying process is as follows: keep warm at 85-95℃ for 4-6 minutes, then keep warm at 105-115℃ for 4-6 minutes, and finally dry at 120-140℃.

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