Thermoplastic polyurethane for waterproof moisture-permeable film as well as preparation method and application of thermoplastic polyurethane

Abstract

The invention provides thermoplastic polyurethane for a waterproof and moisture-permeable film and a preparation method and application thereof.The thermoplastic polyurethane for the waterproof and moisture-permeable film is obtained through a reaction of polymer polyol, isocyanate, a chain extender and small molecule ester, the polymer polyol is polyethylene glycol or a combination of polyethylene glycol and polyester polyol, and the isocyanate is a mixture of isocyanate, a chain extender and small molecule ester. The small molecule ester comprises aliphatic small molecule ester and / or alicyclic small molecule ester; the specific polymer polyol is selected, and the small molecule ester is added in the reaction process, so that the mechanical property and heat resistance of the thermoplastic polyurethane can be further effectively improved on the premise of ensuring that the obtained thermoplastic polyurethane has excellent waterproof and moisture permeable effects; the thermoplastic polyurethane for the waterproof and moisture-permeable film has excellent mechanical properties, heat resistance and waterproof and moisture-permeable properties, and can meet the use requirements of high-performance outdoor clothes.

Description

[0001] This application claims priority to patent application number 202411011333.4 (the earlier application was filed on July 26, 2024, and is entitled "A Thermoplastic Polyurethane for Waterproof and Breathable Membrane and Its Preparation Method and Application"). Technical Field

[0002] This invention belongs to the field of thermoplastic polyurethane technology, specifically relating to a thermoplastic polyurethane for waterproof and breathable membranes, its preparation method, and its application. Background Technology

[0003] Waterproof and breathable are basic functions of outdoor clothing. Generally speaking, waterproof and breathable clothing is mainly achieved by attaching a waterproof and breathable membrane to the surface of the fabric.

[0004] Currently, based on the materials used, commonly used waterproof and breathable membranes mainly include polyurethane (PU) waterproof and breathable membranes and thermoplastic polyurethane (TPU) waterproof and breathable membranes. Among them, TPU can be made into films through processes such as calendering, casting, blown film, and coating. No solvents are used in the film processing, making it more environmentally friendly than PU and the most commonly used material for waterproof and breathable membrane applications. For example, CN107987239A discloses a highly breathable TPU adhesive and its preparation method. The method involves mixing polyol, polyethylene glycol, Bian stone, and tourmaline using a polymer blending device; adding diisocyanate under a protective atmosphere and performing a prepolymerization reaction using the same device; after prepolymerization, adding a chain extender and extruding the mixture through a twin-screw extruder to obtain a waterproof and breathable TPU film material. This invention uses polyol and polyethylene glycol as polyols, which react with diisocyanate to generate polyurethane, introducing hydrophilic groups into the TPU film. The hydrophilic properties of these groups prevent water droplets from penetrating while allowing water vapor to pass through freely, ensuring the stability of the product's breathability and waterproof performance and the durability of its service life.

[0005] However, although the TPU waterproof and breathable membranes provided in the prior art, including the inventions mentioned above, have good waterproof and breathable properties, their heat resistance and mechanical properties are poor, making it difficult to meet the requirements of differentiated products.

[0006] Therefore, it is crucial to develop a thermoplastic polyurethane for waterproof and breathable membranes that combines excellent mechanical properties, heat resistance, and waterproof and breathable properties. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a thermoplastic polyurethane for waterproof and breathable membranes, its preparation method, and its application. The thermoplastic polyurethane for waterproof and breathable membranes is prepared by selecting specific polymeric polyols and adding small molecule esters during the reaction process. This results in a thermoplastic polyurethane that, while possessing good waterproof and breathable properties, also exhibits excellent mechanical and heat resistance properties, meeting the requirements for high-performance outdoor clothing.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a thermoplastic polyurethane for waterproof and breathable membranes, wherein the thermoplastic polyurethane for waterproof and breathable membranes is obtained by reacting polymeric polyols, isocyanates, chain extenders and small molecule esters;

[0010] The polymer polyol is polyethylene glycol (PEG), or a combination of polyethylene glycol and polyester polyol;

[0011] The small molecule esters include any one or a combination of at least two of aliphatic small molecule esters, alicyclic small molecule esters, or aromatic small molecule esters.

[0012] The thermoplastic polyurethane for waterproof and breathable membranes provided by this invention is obtained through the reaction of polymeric polyol, isocyanate, chain extender, and small molecule ester. The polymeric polyol is specifically defined as polyethylene glycol, or a combination of polyethylene glycol and polyester polyol, and the small molecule ester includes any one or a combination of at least two of aliphatic, alicyclic, or aromatic small molecule esters. On one hand, by selecting polyethylene glycol, or a combination of polyethylene glycol and polyester polyol, as the polymeric polyol, the resulting thermoplastic polyurethane exhibits excellent waterproof and breathable properties. On the other hand, by adding small molecule esters during the reaction process, the mechanical properties and heat resistance of the resulting thermoplastic polyurethane can be further effectively improved while ensuring its excellent waterproof and breathable properties. Finally, by selecting specific polymeric polyols and adding small molecule esters during the reaction process, the resulting thermoplastic polyurethane for waterproof and breathable membranes possesses excellent mechanical properties, heat resistance, and waterproof and breathable properties, meeting the requirements for high-performance outdoor clothing.

[0013] Preferably, based on the total mass of all raw materials of the thermoplastic polyurethane used in the waterproof and breathable membrane, the mass of the small molecule ester is ≤1%, for example, 1%, 0.8%, 0.6%, 0.4%, 0.3%, 0.25%, 0.2%, 0.15%, 0.1%, or 0.05%, more preferably ≥0.05% and ≤1%, and even more preferably ≥0.02% and ≤0.5%.

[0014] Preferably, the aliphatic small molecule ester includes any one or a combination of at least two of diethyl adipate (DEA), dioctyl adipate (DOA), dimethyl adipate (DMA), di-n-alkyl adipate, or diisononyl adipate.

[0015] Preferably, the alicyclic small molecule ester includes dioctyl cyclohexane 1,2-dicarboxylate and / or diisononyl cyclohexane 1,2-dicarboxylate.

[0016] Preferably, the number average molecular weight of the polyethylene glycol is ≥2000, such as 2000, 2200, 2400, 2600, 2800, 3000, 3200, 3400, 3600, 3800, 4000, 4500 or 5000, and more preferably 2000 to 4000.

[0017] The present invention further limits the number average molecular weight of the polyethylene glycol to within the above-mentioned range, which can ensure that the obtained waterproof and breathable thermoplastic polyurethane has better mechanical properties, heat resistance and waterproof and breathable properties. If the number average molecular weight of the polyethylene glycol is too low, the mechanical properties and heat resistance of the obtained thermoplastic polyurethane will be low. If the number average molecular weight of the polyethylene glycol is too high, it will be difficult to process.

[0018] Preferably, the polymer polyol is polyethylene glycol and polyester polyol in a mass ratio of (98-70):(2-30).

[0019] The mass ratio of polyethylene glycol to polyester polyol can be 98:2, 95:5, 90:10, 88:12, 85:15, 82:18, 80:20, 75:25, or 70:30, etc.

[0020] Preferably, the number average molecular weight of the polyester polyol is 3000 to 5000, such as 3000, 3200, 3400, 3600, 3800, 4000, 4200, 4400, 4600, 4800 or 5000.

[0021] Preferably, the polyester polyol is obtained by reacting a small molecule diacid with a small molecule diol.

[0022] Preferably, the small molecule dicarboxylic acid includes adipic acid.

[0023] Preferably, the number of carbon atoms in the small molecule diol is 2 to 10, such as 2, 3, 4, 5, 6, 7, 8, 9 or 10, and more preferably 4 to 10.

[0024] Preferably, the polyester polyol comprises any one or a combination of at least two of polyethylene adipate polyol (PEA), polyethylene butylene adipate polyol (PEBA), polybutylene adipate polyol (PBA), polyhexane adipate polyol (PHA), or polyhexane adipate polyol (PHBA), and more preferably any one or a combination of at least two of polybutylene adipate polyol (PBA), polyhexane adipate polyol (PHA), or polyhexane adipate polyol (PHBA).

[0025] Preferably, the isocyanate includes any one or a combination of at least two of methylene diphenyl diisocyanate (MDI), hexamethylene diisocyanate (HDI), or methylene dicyclohexyl diisocyanate (HMDI), and more preferably methylene diphenyl diisocyanate (MDI).

[0026] Preferably, the chain extender comprises aliphatic diols and / or alicyclic diols.

[0027] Preferably, the aliphatic diol includes any one or a combination of at least two of ethylene glycol (EG), 1,2-propanediol (MPG), 1,3-propanediol (PDO), butylene glycol (BDO), or hexanediol (HDO).

[0028] Preferably, the alicyclic diol includes cyclohexanediol (CHD).

[0029] Preferably, the molar ratio of the total hydroxyl groups in the polymer polyol and chain extender to the isocyanate groups in the isocyanate is 1:(0.9-1.05), for example, 1:0.91:1, 1:0.92, 1:0.93, 1:0.94, 1:0.95, 1:0.96, 1:0.97, 1:0.98, 1:0.99, 1:1, 1:1.02, or 1:1.04, etc.

[0030] Preferably, the molar ratio of the polymer polyol to the chain extender is (10-30):(90-70), such as 10:90, 15:85, 20:80, 25:75 or 30:70.

[0031] In a second aspect, the present invention provides a method for preparing a thermoplastic polyurethane for a waterproof and breathable membrane as described in the first aspect, the method comprising: reacting a polymeric polyol, an isocyanate, a chain extender and a small molecule ester to obtain the thermoplastic polyurethane for the waterproof and breathable membrane.

[0032] Preferably, the reaction temperature is 120–200°C, for example, 120°C, 140°C, 160°C, 180°C, or 200°C.

[0033] Preferably, the reaction time is 0.1 to 2 min, for example 0.1 min, 0.2 min, 0.4 min, 0.6 min, 0.8 min, 1 min, 1.2 min, 1.4 min, 1.6 min, 1.8 min or 2 min.

[0034] Thirdly, the present invention provides a waterproof and breathable membrane, wherein the waterproof and breathable membrane is prepared using thermoplastic polyurethane as described in the first aspect.

[0035] Preferably, the preparation process includes any one or a combination of at least two of calendering, casting, blown film, or coating.

[0036] Fourthly, the present invention provides the application of a thermoplastic polyurethane for a waterproof and breathable membrane as described in the first aspect or a waterproof and breathable membrane as described in the third aspect in outdoor clothing.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The thermoplastic polyurethane for waterproof and breathable membranes provided by this invention is obtained through the reaction of polymeric polyol, isocyanate, chain extender, and small molecule ester. The polymeric polyol is polyethylene glycol, or a combination of polyethylene glycol and polyester polyol. The small molecule ester includes aliphatic and / or alicyclic esters. By selecting specific polymeric polyols and adding small molecule esters during the reaction process, the mechanical properties and heat resistance of the thermoplastic polyurethane can be further effectively improved while ensuring its excellent waterproof and breathable properties. This results in a waterproof and breathable membrane thermoplastic polyurethane that combines excellent mechanical properties, heat resistance, and waterproof and breathable properties, meeting the requirements for high-performance outdoor clothing. Detailed Implementation

[0039] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0040] Unless otherwise specified, the raw materials used in the following examples and comparative examples are all existing materials and can be purchased from commercially available products.

[0041] Example 1

[0042] A thermoplastic polyurethane for waterproof and breathable membrane is obtained by reacting polyethylene glycol (number average molecular weight of 3000), polybutylene adipate diol (number average molecular weight of 4000), methylene diphenyl diisocyanate, ethylene glycol and diethyl adipate at 200°C for 1 min.

[0043] The molar ratio of -OH in polyethylene glycol, polybutylene adipate diol and ethylene glycol to -NCO in methylene diphenyl diisocyanate is 1:0.995;

[0044] The mass ratio of polyethylene glycol to polybutylene adipate diol is 95:5;

[0045] The total molar ratio of polyethylene glycol and polybutylene adipate diol to ethylene glycol is 12:88;

[0046] Diethyl adipate accounts for 0.2 wt% of the total mass of all reactants.

[0047] Example 2

[0048] A thermoplastic polyurethane for waterproof and breathable membrane is obtained by reacting polyethylene glycol (number average molecular weight of 4000), methylene diphenyl diisocyanate, 1,6-hexanediol and dioctyl adipate at 200°C for 1 min.

[0049] The molar ratio of -OH in polyethylene glycol and 1,6-hexanediol to -NCO in methylene diphenyl diisocyanate is 1:1.

[0050] The molar ratio of polyethylene glycol to 1,6-hexanediol is 16:84;

[0051] Dioctyl adipate accounts for 0.1 wt% of the total mass of all reactants.

[0052] Example 3

[0053] A thermoplastic polyurethane for waterproof and breathable membrane is obtained by reacting polyethylene glycol (number average molecular weight of 2000), polyhexane adipate diol (number average molecular weight of 3000), methylene diphenyl diisocyanate, 1,3-propanediol and dimethyl adipate at 200°C for 1 min.

[0054] The molar ratio of -OH in polyethylene glycol, polyhexamethylene adipate diol and 1,3-propanediol to -NCO in methylene diphenyl diisocyanate is 1:0.998.

[0055] The mass ratio of polyethylene glycol to polyhexyl adipate diol is 80:20;

[0056] The total molar ratio of polyethylene glycol and polyhexyl adipate diol to 1,3-propanediol is 20:80.

[0057] Dimethyl adipate accounts for 0.05 wt% of the total mass of all reactants.

[0058] Example 4

[0059] A thermoplastic polyurethane for waterproof and breathable membrane, which differs from Example 1 in that diisononyl cyclohexane 1,2-dicarboxylate is used instead of diethyl adipate, while other substances, amounts and parameters are the same as in Example 1.

[0060] Example 5

[0061] A thermoplastic polyurethane for waterproof and breathable membrane, which differs from Example 1 in that diethyl adipate accounts for 1.2 wt% of the total mass of all raw materials, while the other substances, amounts and parameters are the same as in Example 1.

[0062] Example 6

[0063] A thermoplastic polyurethane for waterproof and breathable membrane, which differs from Example 1 in that diethyl adipate accounts for 0.8 wt% of the total mass of all raw materials, while other substances, amounts and parameters are the same as in Example 1.

[0064] Example 7

[0065] A thermoplastic polyurethane for waterproof and breathable membrane, which differs from Example 1 in that diethyl adipate accounts for 0.01 wt% of the total mass of all raw materials, while other substances, amounts and parameters are the same as in Example 1.

[0066] Example 8

[0067] A thermoplastic polyurethane for waterproof and breathable membrane, which differs from Example 1 in that di(2-ethylhexyl) phthalate is used instead of diethyl adipate, while other substances, amounts and parameters are the same as in Example 1.

[0068] Example 9

[0069] A thermoplastic polyurethane for waterproof and breathable membrane, which differs from Example 1 in that the number average molecular weight of polyethylene glycol is 5000, while the other substances, amounts and parameters are the same as in Example 1.

[0070] Example 10

[0071] A thermoplastic polyurethane for waterproof and breathable membrane, which differs from Example 1 in that the number average molecular weight of polyethylene glycol is 1500, while the other substances, amounts and parameters are the same as in Example 1.

[0072] Example 11

[0073] A thermoplastic polyurethane for waterproof and breathable membrane, which differs from Example 1 in that polypropylene adipate diol (number average molecular weight 4000) replaces polybutylene adipate diol (number average molecular weight 4000), while other substances, amounts and parameters are the same as in Example 1.

[0074] Example 12

[0075] A thermoplastic polyurethane for waterproof and breathable membrane, which differs from Example 1 in that the mass ratio of polyethylene glycol to polybutylene adipate diol is 65:35, while the other substances, amounts and parameters are the same as in Example 1.

[0076] Comparative Example 1

[0077] A thermoplastic polyurethane for waterproof and breathable membrane, which differs from Example 1 in that diethyl adipate is not added, while other substances, amounts and parameters are the same as in Example 1.

[0078] Comparative Example 2

[0079] A thermoplastic polyurethane for waterproof and breathable membrane, which differs from Example 1 in that the preparation method is different, while the other substances, amounts and parameters are the same as in Example 1;

[0080] The method for preparing the thermoplastic polyurethane for waterproof and breathable membrane provided in this comparative example includes: reacting polyethylene glycol (number average molecular weight of 3000), polybutylene adipate diol (number average molecular weight of 4000), methylene diphenyl diisocyanate and ethylene glycol at 100°C for 1 min, and mixing with diethyl adipate after the reaction to obtain the thermoplastic polyurethane for waterproof and breathable membrane.

[0081] Comparative Example 3

[0082] A thermoplastic polyurethane for waterproof and breathable membrane, which differs from Example 1 in that polyethylene glycol is not added, while other substances, amounts and parameters are the same as in Example 1.

[0083] Comparative Example 4

[0084] A thermoplastic polyurethane for waterproof and breathable membrane, which differs from Example 1 in that an equimolar amount of polytetramethylene ether glycol (number average molecular weight of 3000) is used instead of polyethylene glycol, while other substances, amounts and parameters are the same as in Example 1.

[0085] Comparative Example 5

[0086] A thermoplastic polyurethane for waterproof and breathable membrane, which differs from Example 1 in that an equimolar amount of polypropylene glycol (number average molecular weight of 3000) is used instead of polyethylene glycol, while other substances, amounts and parameters are the same as in Example 1.

[0087] Performance testing:

[0088] (1) Waterproof and breathable properties: After the thermoplastic polyurethane is processed into a polyurethane film using a casting process, the film is tested according to the inverted cup method specified in standard ASTM E96, with a film thickness of 0.015 mm.

[0089] (2) Tensile strength: Tested according to the method specified in standard ASTM D412.

[0090] (3) Initial flow temperature (Tfb): The initial flow temperature of thermoplastic polyurethane was determined using the Shimadzu rheometer heating method at a heating rate of 5℃ / min and a test load of 10kg.

[0091] (4) Water pressure resistance: After the thermoplastic polyurethane is processed into a polyurethane film by casting process, it is tested according to the method specified in AATCC 127, and the film thickness is 0.015mm.

[0092] Thermoplastic polyurethane for waterproof and breathable membranes provided in Examples 1-12 and Comparative Examples 1-5 were tested according to the above test methods. The test results are shown in Table 1.

[0093] Table 1

[0094]

[0095]

[0096] According to the data in Table 1:

[0097] The thermoplastic polyurethanes provided in Examples 1 and 2 have excellent waterproof and breathable properties, high tensile strength, high initial flow temperature, and high water pressure resistance.

[0098] The thermoplastic polyurethane provided in Comparative Example 1, due to the absence of small molecule esters, exhibited a significant decrease in its waterproof and breathable properties, tensile strength, initial flow temperature, and water pressure resistance.

[0099] The thermoplastic polyurethane provided in Comparative Example 2 had small molecule esters added only after polymerization. Although the waterproof and breathable properties, tensile strength, initial flow temperature and water pressure resistance were improved compared to Comparative Example 1, the improvement was very limited and still far lower than that in Example 1.

[0100] The thermoplastic polyurethane provided in Comparative Example 3 uses only polybutylene adipate diol as the polymer polyol, without adding polyethylene glycol, resulting in very poor waterproof and breathable properties.

[0101] Comparative Examples 4 and 5, which replaced polyethylene glycol with polytetramethylene ether glycol and polypropylene glycol respectively, also failed to produce thermoplastic polyurethanes with excellent waterproof and breathable properties, mechanical properties, and heat resistance.

[0102] The applicant declares that this invention illustrates a thermoplastic polyurethane for waterproof and breathable membranes, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the product, additions of auxiliary components, and selection of specific methods all fall within the protection and disclosure scope of this invention.

Claims

1. A thermoplastic polyurethane for a waterproof and breathable membrane, characterized in that, The waterproof and breathable membrane is obtained by reacting thermoplastic polyurethane with polymer polyol, isocyanate, chain extender and small molecule ester; The polymer polyol is polyethylene glycol, or a combination of polyethylene glycol and polyester polyol; The small molecule esters include any one or a combination of at least two of aliphatic small molecule esters, alicyclic small molecule esters, or aromatic small molecule esters.

2. The thermoplastic polyurethane for waterproof and breathable membrane according to claim 1, characterized in that, The small molecule esters include aliphatic small molecule esters and / or alicyclic small molecule esters; Preferably, based on the mass of all raw materials of the thermoplastic polyurethane used in the waterproof and breathable membrane as 100%, the mass of the small molecule ester is ≤1%, more preferably ≥0.05% and ≤1%, and even more preferably ≥0.05% and ≤0.5%. Preferably, the aliphatic small molecule ester includes any one or a combination of at least two of diethyl adipate, dioctyl adipate, dimethyl adipate, di-n-alkyl adipate, or diisononyl adipate. Preferably, the alicyclic small molecule ester includes dioctyl cyclohexane-1,2-dicarboxylate and / or diisononyl cyclohexane-1,2-dicarboxylate.

3. The thermoplastic polyurethane for waterproof and breathable membranes according to claim 1 or 2, characterized in that, The number average molecular weight of the polyethylene glycol is ≥2000, preferably 2000-4000; Preferably, the polymer polyol is a combination of polyethylene glycol and polyester polyol in a mass ratio of (98-70):(2-30); Preferably, the number-average molecular weight of the polyester polyol is 3000-5000; Preferably, the polyester polyol is obtained by reacting a small molecule diacid with a small molecule diol; Preferably, the small molecule dicarboxylic acid includes adipic acid; Preferably, the small molecule diol has 2 to 10 carbon atoms, more preferably 4 to 10; Preferably, the polyester polyol comprises any one or a combination of at least two of polyethylene adipate polyol, polyethylene butylene adipate polyol, polybutylene adipate polyol, polyhexanediol adipate polyol, or polyhexanediol adipate polyol, and more preferably any one or a combination of at least two of polybutylene adipate polyol, polyhexanediol adipate polyol, or polyhexanediol adipate polyol.

4. The thermoplastic polyurethane for waterproof and breathable membranes according to any one of claims 1 to 3, characterized in that, The isocyanate includes any one or a combination of at least two of methylene diphenyl diisocyanate, hexamethylene diisocyanate, or methylene dicyclohexyl diisocyanate, preferably methylene diphenyl diisocyanate.

5. The thermoplastic polyurethane for waterproof and breathable membranes according to any one of claims 1 to 4, characterized in that, The chain extender includes aliphatic diols and / or alicyclic diols; Preferably, the aliphatic diol includes any one or a combination of at least two of ethylene glycol, 1,2-propanediol, 1,3-propanediol, butanediol, or hexanediol; Preferably, the alicyclic diol includes cyclohexanediol.

6. The thermoplastic polyurethane for waterproof and breathable membranes according to any one of claims 1 to 5, characterized in that, The molar ratio of the total hydroxyl groups in the polymer polyol and chain extender to the isocyanate groups in the isocyanate is 1:(0.9-1.05); Preferably, the molar ratio of the polymer polyol to the chain extender is (10-30):(90-70).

7. A method for preparing a thermoplastic polyurethane for a waterproof and breathable membrane as described in any one of claims 1 to 6, characterized in that, The preparation method includes reacting polymeric polyol, isocyanate, chain extender and small molecule ester to obtain the thermoplastic polyurethane for waterproof and breathable membrane.

8. A waterproof and breathable membrane, characterized in that, The waterproof and breathable membrane is prepared using thermoplastic polyurethane as described in any one of claims 1 to 6.

9. The waterproof and breathable membrane according to claim 8, characterized in that, The preparation process includes any one or a combination of at least two of calendering, casting, blown film, or coating.

10. The application of a thermoplastic polyurethane for a waterproof and breathable membrane as described in any one of claims 1 to 6, or the waterproof and breathable membrane as described in claim 9, in outdoor clothing.

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