Polyurethane wet resin for soft embossing-resistant clothing leather and preparation method of polyurethane wet resin

Abstract

The invention provides polyurethane wet resin for soft embossing-resistant clothing leather as well as a preparation method and application of the polyurethane wet resin. The preparation raw materials of the polyurethane wet resin comprise the following components in parts by weight: 0.002-0.004 part of inorganic acid; 165 to 251 parts of polyester polyol; 42 to 64 parts of isocyanate; 7-11 parts of small molecular alcohol; 24 to 37 parts of an auxiliary agent; 560 to 840 parts of a solvent; the polyester polyol simultaneously comprises polyester polyol of an adipic acid-ethylene glycol-1, 4-butanediol system, polyester polyol of an adipic acid-phthalic acid-ethylene glycol-1, 4-butanediol system, polyester polyol of an adipic acid-phthalic acid-ethylene glycol-1, 4- The polyester polyol is prepared from polyester polyol of a 1, 4-butanediol system, polyester polyol of an adipic acid-diethylene glycol-ethylene glycol system, polyester polyol of an adipic acid-diethylene glycol system and polyester polyol of an adipic acid-ethylene glycol system. The polyurethane wet resin disclosed by the invention has the characteristics of good finger-pressing resilience, thick and soft hand feeling, good black color developing property and the like, and the prepared synthetic leather keeps good high-temperature embossing resilience and combines the thick and soft hand feeling, so that the additional value of the product is obviously improved.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane materials, and in particular relates to a polyurethane wet-process resin for soft embossing-resistant clothing leather, a preparation method and an application thereof. Background Art

[0002] Wet resin for garment leather refers to a process in which the prepared wet resin is first passed through a scraper of fixed thickness of viscose cloth into water for solidification, washing, drying and other series of processes to form a wet base, and then a layer of dry fabric is attached to make garment leather, and then it is embossed with a specific pattern mold at high temperature to form synthetic leather.

[0003] Currently, there are two types of wet-process resins for soft embossing and medium-hard embossing. Soft embossing wet-process resins are produced by adding a heat-resistant additive or a hard wet-process resin to a soft embossing wet-process polyurethane resin, using a wet-process process for garment leather to create synthetic leather. However, this method has the disadvantage that the resulting synthetic leather often exhibits stiffness, poor rebound, and low thickness after embossing. Medium-hard embossing wet-process resins are produced by adding a large amount of softener or wood powder filler to a medium-hard embossing wet-process polyurethane resin, using a wet-process process for garment leather to create synthetic leather. However, this method also has the disadvantage that the resulting synthetic leather has unclear surface texture, low peel strength, and a hard feel after embossing. Currently available soft and medium-hard embossing wet-process resins fail to simultaneously achieve the desired properties of thick feel, clear texture, and moderate peel strength after embossing. Therefore, the development of a soft, emboss-resistant polyurethane wet-process resin for garment leather is highly desirable. Summary of the Invention

[0004] In view of the problems that existing synthetic leather tends to feel stiff and have poor temperature resistance after high-temperature embossing, the thickness retention rate of synthetic leather before and after embossing is low, and the clarity of the texture is affected by the use of too much filler in the product, the purpose of the present invention is to provide a polyurethane wet-process resin for soft embossing-resistant clothing leather, as well as its preparation method and application.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a polyurethane wet-process resin for soft embossing-resistant garment leather, wherein the raw materials for preparing the resin include the following components in parts by weight:

[0007] 0.002-0.004 parts of inorganic acid;

[0008] 165-251 parts of polyester polyol;

[0009] 42-64 parts of isocyanate;

[0010] 7-11 parts of small molecule alcohol;

[0011] 24-37 parts of additives;

[0012] 560-840 parts of solvent; the polyester polyol also includes: polyester polyol of adipic acid-ethylene glycol-1,4-butanediol system (PE-1), polyester polyol of adipic acid-phthalic acid-ethylene glycol-1,4-butanediol system (PE-2), polyester polyol of adipic acid-diethylene glycol-ethylene glycol system (PE-3), polyester polyol of adipic acid-diethylene glycol system (PE-4) and polyester polyol of adipic acid-ethylene glycol system (PE-5).

[0013] Preferably, the inorganic acid is concentrated phosphoric acid.

[0014] Preferably, the molecular weight of the polyester polyol of the adipic acid-ethylene glycol-1,4-butanediol system is 5800-6200, the molecular weight of the polyester polyol of the adipic acid-phthalic acid-ethylene glycol-1,4-butanediol system is 3800-4200, the molecular weight of the polyester polyol of the adipic acid-diethylene glycol system and the polyester polyol of the adipic acid-ethylene glycol-diethylene glycol system are both 1800-2200, and the molecular weight of the polyester polyol of the adipic acid-ethylene glycol system is 800-1200.

[0015] Preferably, the mass ratio of the polyester polyols of adipic acid-ethylene glycol-1,4-butanediol system, the polyester polyols of adipic acid-phthalic acid-ethylene glycol-1,4-butanediol system, the polyester polyols of adipic acid-diethylene glycol-ethylene glycol system, the polyester polyols of adipic acid-diethylene glycol system and the polyester polyols of adipic acid-ethylene glycol system in the polyester polyols is 40-48:20-30:15-20:5-10:3-7.

[0016] Preferably, the isocyanate is one or more of diphenylmethane diisocyanate, dimethyldiphenylmethane diisocyanate, and polymethylene polyphenyl isocyanate.

[0017] Preferably, the small molecule alcohol is one or more of ethylene glycol, 1,4-butanediol, diethylene glycol, and 1,3-butanediol.

[0018] Preferably, the solvent is N,N-dimethylformamide, and the auxiliary agent is one or more of a water-assisting agent, a stabilizer, and a capping agent.

[0019] Preferably, the water-assisting agent is polyether polyol and silicone-based auxiliary agent, the stabilizer is malic acid, and the end-capping agent is methanol.

[0020] In a second aspect, the present invention further provides a method for preparing the above-mentioned polyurethane wet resin for soft embossing-resistant garment leather, characterized in that it comprises the following steps:

[0021] First, prepare a polyurethane wet resin intermediate, and the preparation steps are as follows:

[0022] (1) mixing a polyester polyol of adipic acid-diethylene glycol-ethylene glycol system, a polyester polyol of adipic acid-diethylene glycol system, a hindered phenol antioxidant accounting for 40-60% (preferably 50%) of the total amount, an inorganic acid accounting for 40-60% (preferably 50%) of the total amount, and a solvent accounting for 4-6% (preferably 5%) of the total amount in the polyester polyol, and heating the mixture;

[0023] (2) adding 10-14% (preferably 12%) of isocyanate to the mixture treated in step (1) to carry out the reaction, maintaining the R value at 0.95-1.05, the reaction viscosity at 6-7 Pas / 70 degrees, and the solid content of the reaction liquid at 61%-62%;

[0024] (3) adding 4-6% (preferably 5%) of a solvent and 24-28% (preferably 26%) of a small molecule alcohol to the mixture after treatment in step (2), and treating at a constant temperature;

[0025] (4) adding 15-19% (preferably 17%) of isocyanate to the mixture after treatment in step (3) and treating at a constant temperature;

[0026] (5) adding 0.5-1.5% (preferably 1%) of isocyanate to the mixture after treatment in step (4) to carry out the reaction, maintaining the R value at 0.9-1.1, adding 10-16% of solvent to the reaction viscosity of 10-14 Pas / 25 degrees, and the solid content of the reaction liquid is 30%-31%, and then adding 40-60% (preferably 50%) of the blocking agent to stir and cool;

[0027] (6) Adding 40-60% (preferably 50%) of a stabilizer to the mixture after treatment in step (5) and stirring to obtain an intermediate of the polyurethane wet impregnation resin.

[0028] Then, prepare the polyurethane wet resin, and its preparation steps are as follows:

[0029] (a) mixing a polyester polyol of an adipic acid-ethylene glycol-1,4-butanediol system, a polyester polyol of an adipic acid-phthalic acid-ethylene glycol-1,4-butanediol system, a hindered phenol antioxidant accounting for 40-60% (preferably 50%) of the total amount, an inorganic acid accounting for 40-60% (preferably 50%) of the total amount, and a solvent accounting for 16-20% (preferably 18%) of the total amount, and heating the mixture;

[0030] (b) adding 10-12% (preferably 11%) of isocyanate to the mixture after treatment in step (a) to carry out reaction, maintaining the R value at 0.85-0.87 and the solid content of the reaction solution at 53%-54%, and treating at a constant temperature;

[0031] (c) adding 16-20% (preferably 18%) of a solvent and 70-78% (preferably 74%) of a low-molecular-weight alcohol to the mixture after treatment in step (b), and treating at a constant temperature;

[0032] (d) adding 40-60% (preferably 50%) of isocyanate to the mixture after treatment in step (c), and treating at a constant temperature;

[0033] (e) adding the remaining 5-13% (preferably 9%) of the isocyanate to the mixture after treatment in step (d) to carry out the reaction, maintaining the R value at 0.9-1.1, adding the remaining 40-42% (preferably 41%) of the solvent until the reaction viscosity reaches 24-28 Pas / 25 degrees and the solid content of the reaction solution reaches 30%-31%, and then adding 40-60% (preferably 50%) of the blocking agent, stirring, and cooling;

[0034] (f) adding 40-60% of a stabilizer, 20-28% (preferably 24%) of a polyurethane wet process resin intermediate, and a water-assistant to the mixture after treatment in step (e), and stirring to obtain the polyurethane wet process resin.

[0035] Preferably, the preparation of the polyurethane wet process resin intermediate is carried out in a reactor.

[0036] Preferably, in step (1), the temperature is raised to 40°C-50°C, and after the temperature is raised, the mixture is stirred at the constant temperature for 20-40 minutes. Preferably, based on the total mass of the solvent being 100%, the mass percentage of the solvent in step (1) is 5.2%.

[0037] Preferably, in step (2), the isothermal treatment is carried out at 70-75° C. with stirring for 1-3 hours. Preferably, the mass percentage of the isocyanate in step (2) is 12.5%, based on the total mass of the isocyanate being 100%.

[0038] Preferably, in step (3), the constant temperature treatment condition is stirring at 60°C-65°C for 20-40 minutes. Preferably, based on the total mass of the small molecule alcohol as 100%, in step (3), the mass percentage of the small molecule alcohol is 26%; and the amount of solvent added is 5.4% of the total amount of solvent.

[0039] Preferably, in step (4), the constant temperature treatment condition is stirring at 70° C.-75° C. for 1-3 hours; and the amount of isocyanate added is 17.8% of the total amount of isocyanate.

[0040] Preferably, in step (5), the temperature is controlled at 70° C.-75° C. during the addition of the remaining isocyanate.

[0041] Preferably, the preparation of the polyurethane wet resin is carried out in a reactor

[0042] Preferably, in step (a), the temperature is raised to 40°C-50°C, and after the temperature is raised, the temperature is maintained at a constant temperature with stirring for 20-40 minutes. Preferably, based on the total mass of the solvent being 100%, the mass percentage of the solvent in step (a) is 18.4%.

[0043] Preferably, in step (b), the isothermal treatment is carried out at 70-75° C. with stirring for 1-3 hours. Preferably, based on the total mass of the isocyanate being 100%, the mass percentage of the isocyanate in step (b) is 11.5%.

[0044] Preferably, in step (c), the constant temperature treatment condition is stirring at 60°C-65°C for 20-40 minutes. Preferably, based on the total mass of the small molecule alcohol as 100%, in step (c), the mass percentage of the small molecule alcohol is 74%; and the amount of solvent added is 11.5% of the total amount of solvent.

[0045] Preferably, in step (d), the constant temperature treatment condition is stirring at 70° C.-75° C. for 1-3 hours; and the amount of isocyanate added is 51% of the total amount of isocyanate.

[0046] Preferably, in step (e), the temperature is controlled at 70° C.-75° C. during the addition of the remaining isocyanate.

[0047] In a third aspect, the present invention further provides a synthetic leather, which is prepared using the above-mentioned polyurethane wet process resin for soft embossing-resistant clothing leather, or prepared using the above-mentioned method for preparing the polyurethane wet process resin for soft embossing-resistant clothing leather.

[0048] Beneficial effects: (1) The present invention improves the film-forming property and soft and thick feel of the surface of synthetic leather by compounding and selecting polyester polyols (PE1, PE2 and PE5) with different structures; improves the color development and thickness of the resin, which is easier to coordinate the changes in the main performance than using a single-structure polyester polyol; uses ethylene glycol as a chain extender to increase the resin solidification speed to make the resin more uniform while ensuring the improvement of the hand feel, and increases the modulus, temperature resistance and gloss of the resin by increasing the amount of chain extender, which is easier to adjust than using a chain extender with a side group; in the selection of auxiliary agents, an auxiliary agent that is conducive to uniform solidification, water-assisted washing and improves the gloss of synthetic leather is selected, which significantly improves the surface gloss, soft and thick feel and thickness of synthetic leather.

[0049] (2) In the preparation of the polyurethane wet-process resin of the present invention, by adjusting the ratio of conventional structure and special structure polyester polyols and combining them with chain extenders, additives, etc. and combining them with the improvement of new processes, the solidification speed, modulus, thickness and temperature resistance of the resin are significantly improved. In the preparation of the resin, the amount of polyester polyol with a special molecular weight of adipic acid-ethylene glycol-1,4-butanediol structure and polyester polyol with a conventional molecular weight of adipic acid-phthalic acid-ethylene glycol-1,4-butanediol structure is increased to reduce costs and increase added value; under the premise of using the same materials and the same synthetic leather base thickness in leather making, more materials can be saved to reduce costs and increase production speed.

[0050] (3) In the preparation of the polyurethane wet resin of the present invention, by first selecting a special structure polyester polyol PE-1 and PE-2, using a small amount of phthalic acid structure and selecting different molecular weights, the thickness and color development of the resin can be improved and the amount of chain extender and isocyanate can be reduced; then, when adding a specific amount of ethylene glycol, adding a small amount of PE-5 polyester polyol can improve the temperature resistance and peel strength of the resin, and combined with a specific process design, it plays a key role in the preparation of the polyurethane wet resin.

[0051] (4) In the preparation of the polyurethane wet resin of the present invention, a specific molecular weight of 2000 is selected and matched by selecting two polyester polyols of adipic acid-diethylene glycol-ethylene glycol structure and polyester polyols of adipic acid-diethylene glycol structure, and then synthesized as an intermediate by a special process to ensure the peel strength, water washing, color development, feel and thickness of the polyurethane wet resin.

[0052] (5) In the preparation of the polyurethane wet resin of the present invention, by selecting a combination of polyols with different structures in the first step, pre-polymerization is performed to increase the viscosity to 6-7pas / 70 degrees, and then ethylene glycol is added to continue to increase the viscosity according to the steps to the standard set viscosity and solid content to obtain an intermediate; combined with the different main processes, the washability and thickness of the polyurethane wet resin can be improved, which plays a decisive role in the smoothness and gloss of the surface of the corresponding synthetic leather. DETAILED DESCRIPTION

[0053] The technical solution of the present invention will be further described below through specific implementation methods.

[0054] The embodiments are only for helping to understand the present invention and should not be considered as limiting the present invention.

[0055] The raw materials used in the examples of the present invention and the comparative examples are as follows:

[0056] PE-1 (AA-EG-BG): molecular weight 6000;

[0057] PE-17 (AA-EG-BG): molecular weight 4000;

[0058] PE-2 (AA-PA-EG-BG): molecular weight 4000;

[0059] PE-3(AA-EG-DEG): molecular weight 2000;

[0060] PE-4 (AA-DEG): molecular weight 2000;

[0061] PE-5 (AA-EG): molecular weight is 1000;

[0062] PE-6 (AA-BG): molecular weight 1000;

[0063] Hindered phenol antioxidant: ROX-13TP (manufacturer: Double Bond Chemical Co., Ltd., model: Antioxidant 1330);

[0064] Water-assistant detergent polyether polyol: XP-555 (manufacturer: Polyether Department of Sinopec Tianjin Petrochemical Company, model: TMD-5000);

[0065] Water-assistant detergent silicone additive: XP-888 (manufacturer: Lishui Wanhong Polymer New Materials Co., Ltd., model: super soft softener 6062).

[0066] The PE raw materials used in the present invention are all synthesized in the laboratory, and the others are commercially available products.

[0067] Example 1

[0068] A polyurethane wet-process resin for soft, embossing-resistant garment leather, the raw materials for its preparation comprising the following components:

[0069] PE-1: 90g, PE-2: 54g, PE-3: 37g, PE-4: 16g, PE-5: 10g, hindered phenol antioxidant ROX-13TP: 0.2g, concentrated phosphoric acid: 0.003g, EG: 9.1g, DMF: 700g, MDI: 53g, methanol: 0.4g, benzoic acid: 0.4g, polyether polyol XP-555: 10g, silicone additive XP-888: 20g.

[0070] The above-mentioned polyurethane wet resin preparation method is as follows.

[0071] First, prepare a polyurethane wet resin intermediate, and the preparation steps are as follows:

[0072] (1) 37 g of polyester polyol PE-3 of adipic acid-diethylene glycol-ethylene glycol system, 16 g of polyester polyol PE-4 of adipic acid-diethylene glycol system, 0.1 g of hindered phenol antioxidant accounting for 50% (calculated as 100%) of the total amount, 0.0015 g of inorganic acid accounting for 50% (calculated as 100%) of the total amount, and 35 g of solvent accounting for 5% (calculated as 100%) of the total amount were mixed and heated;

[0073] (2) adding 6.36 g of isocyanate (12% of the total amount (calculated as 100%)) to the mixture treated in step (1) to carry out the reaction, maintaining the R value at 0.95-1.05, the reaction viscosity at 6-7 Pas / 70 degrees, and the solid content of the reaction liquid at 61%-62%;

[0074] (3) adding 35 g of solvent (5% of the total amount) and 2.36 g of low-molecular alcohol (26% of the total amount, calculated as 100%) to the mixture after treatment in step (2), and treating at a constant temperature;

[0075] (4) adding 9.01 g of isocyanate (accounting for 17% of the total amount) to the mixture after treatment in step (3) and treating at a constant temperature;

[0076] (5) Add 0.53 g of isocyanate (1% of the total amount) to the mixture treated in step (4) and react while maintaining the R value at 0.9-1.1. Add 91 g of solvent (13% of the total amount) until the reaction viscosity reaches 10-14 Pas / 25 degrees and the solid content of the reaction solution reaches 30%-31%. Then add 0.2 g of a blocking agent, stir, and cool.

[0077] (6) Add 0.2 g of stabilizer to the mixture treated in step (5) and stir to obtain an intermediate of the polyurethane wet process resin.

[0078] Then, prepare the polyurethane wet resin, and its preparation steps are as follows:

[0079] (a) 90 g of polyester polyol PE-1 of adipic acid-ethylene glycol-1,4-butanediol system, 54 g of polyester polyol PE-2 of adipic acid-phthalic acid-ethylene glycol-1,4-butanediol system, 0.1 g of hindered phenol antioxidant accounting for 50% of the total amount, 0.0015 g of inorganic acid accounting for 50% of the total amount, and 126 g of solvent accounting for 18% of the total amount were mixed and heated;

[0080] (b) adding 5.83 g of isocyanate (11% of the total amount) to the mixture after treatment in step (a) to carry out the reaction, maintaining the R value at 0.85-0.87 and the solid content of the reaction solution at 53%-54%, and treating at a constant temperature;

[0081] (c) adding 126 g of a solvent accounting for 18% of the total amount, 6.73 g of a small molecule alcohol accounting for 74% of the total amount, and 10 g of a polyester polyol PE-5 of adipic acid-ethylene glycol system to the mixture after treatment in step (b), and treating at a constant temperature;

[0082] (d) adding 26.5 g of isocyanate (50% of the total amount) to the mixture after treatment in step (c) and treating at a constant temperature;

[0083] (e) adding 4.77 g of isocyanate (9% of the total amount) to the mixture treated in step (d) to react while maintaining the R value at 0.9-1.1, adding 287 g of solvent (41% of the total amount) until the reaction viscosity reaches 24-28 Pas / 25 degrees and the solid content of the reaction solution reaches 30%-31%, and then adding 0.2 g of a blocking agent, stirring, and cooling;

[0084] (f) adding 0.2 g of a stabilizer, a polyurethane wet process resin intermediate accounting for 24% of the total amount of the resin, and water-assisting agents XP-555 and XP-888 to the mixture after treatment in step (e) and stirring to obtain the polyurethane wet process resin.

[0085] Example 2

[0086] A polyurethane wet-process resin for soft, embossing-resistant garment leather, the raw materials for its preparation comprising the following components:

[0087] PE-1: 54g, PE-2: 90g, PE-3: 37g, PE-4: 16g, PE-5: 10g, hindered phenol antioxidant ROX-13TP: 0.2g, concentrated phosphoric acid: 0.003g, EG: 9.1g, DMF: 700g, MDI: 53g, methanol: 0.4g, benzoic acid: 0.4g, polyether polyol XP-555: 10g, silicone additive XP-888: 20g.

[0088] The above-mentioned polyurethane wet resin preparation method is as follows.

[0089] First, prepare a polyurethane wet resin intermediate, and the preparation steps are as follows:

[0090] (1) 37 g of polyester polyol PE-3 of adipic acid-diethylene glycol-ethylene glycol system, 16 g of polyester polyol PE-4 of adipic acid-diethylene glycol system, 0.1 g of hindered phenol antioxidant accounting for 50% (calculated as 100%) of the total amount, 0.0015 g of inorganic acid accounting for 50% (calculated as 100%) of the total amount, and 35 g of solvent accounting for 5% (calculated as 100%) of the total amount were mixed and heated;

[0091] (2) adding 6.36 g of isocyanate (12% of the total amount (calculated as 100%)) to the mixture treated in step (1) to carry out the reaction, maintaining the R value at 0.95-1.05, the reaction viscosity at 6-7 Pas / 70 degrees, and the solid content of the reaction liquid at 61%-62%;

[0092] (3) adding 35 g of solvent (5% of the total amount) and 2.36 g of low-molecular alcohol (26% of the total amount, calculated as 100%) to the mixture after treatment in step (2), and treating at a constant temperature;

[0093] (4) adding 9.01 g of isocyanate (accounting for 17% of the total amount) to the mixture after treatment in step (3) and treating at a constant temperature;

[0094] (5) Add 0.53 g of isocyanate (1% of the total amount) to the mixture treated in step (4) and react while maintaining the R value at 0.9-1.1. Add 91 g of solvent (13% of the total amount) until the reaction viscosity reaches 10-14 Pas / 25 degrees and the solid content of the reaction solution reaches 30%-31%. Then add 0.2 g of a blocking agent, stir, and cool.

[0095] (6) Add 0.2 g of stabilizer to the mixture treated in step (5) and stir to obtain an intermediate of the polyurethane wet process resin.

[0096] Then, prepare the polyurethane wet resin, and its preparation steps are as follows:

[0097] (a) 54 g of polyester polyol PE-1 of adipic acid-ethylene glycol-1,4-butanediol system, 90 g of polyester polyol PE-2 of adipic acid-phthalic acid-ethylene glycol-1,4-butanediol system, 0.1 g of hindered phenol antioxidant accounting for 50% of the total amount, 0.0015 g of inorganic acid accounting for 50% of the total amount, and 126 g of solvent accounting for 18% of the total amount were mixed and heated;

[0098] (b) adding 5.83 g of isocyanate (11% of the total amount) to the mixture after treatment in step (a) to carry out the reaction, maintaining the R value at 0.85-0.87 and the solid content of the reaction solution at 53%-54%, and treating at a constant temperature;

[0099] (c) adding 126 g of a solvent accounting for 18% of the total amount, 6.73 g of a small molecule alcohol accounting for 74% of the total amount, and 10 g of a polyester polyol PE-5 of adipic acid-ethylene glycol system to the mixture after treatment in step (b), and treating at a constant temperature;

[0100] (d) adding 26.5 g of isocyanate (50% of the total amount) to the mixture after treatment in step (c) and treating at a constant temperature;

[0101] (e) adding 4.77 g of isocyanate (9% of the total amount) to the mixture treated in step (d) to react while maintaining the R value at 0.9-1.1, adding 287 g of solvent (41% of the total amount) until the reaction viscosity reaches 24-28 Pas / 25 degrees and the solid content of the reaction solution reaches 30%-31%, and then adding 0.2 g of a blocking agent, stirring, and cooling;

[0102] (f) adding 0.2 g of a stabilizer, a polyurethane wet process resin intermediate accounting for 24% of the total amount of the resin, and water-assisting agents XP-555 and XP-888 to the mixture after treatment in step (e) and stirring to obtain the polyurethane wet process resin.

[0103] Example 3

[0104] A polyurethane wet-process resin for soft, embossing-resistant garment leather, the raw materials for its preparation comprising the following components:

[0105] PE-1: 90g, PE-2: 54g, PE-3: 16g, PE-4: 37g, PE-5: 10g, hindered phenol antioxidant ROX-13TP: 0.2g, concentrated phosphoric acid: 0.003g, EG: 9.1g, DMF: 700g, MDI: 53g, methanol: 0.4g, benzoic acid: 0.4g, polyether polyol XP-555: 10g, silicone additive XP-888: 20g.

[0106] The above-mentioned polyurethane wet resin preparation method is as follows.

[0107] First, prepare a polyurethane wet resin intermediate, and the preparation steps are as follows:

[0108] (1) 16 g of polyester polyol PE-3 of adipic acid-diethylene glycol-ethylene glycol system, 37 g of polyester polyol PE-4 of adipic acid-diethylene glycol system, 0.1 g of hindered phenol antioxidant accounting for 50% of the total amount (calculated as 100%), 0.0015 g of inorganic acid accounting for 50% of the total amount (calculated as 100%), and 35 g of solvent accounting for 5% of the total amount (calculated as 100%) were mixed and heated;

[0109] (2) adding 6.36 g of isocyanate (12% of the total amount (calculated as 100%)) to the mixture treated in step (1) to carry out the reaction, maintaining the R value at 0.95-1.05, the reaction viscosity at 6-7 Pas / 70 degrees, and the solid content of the reaction liquid at 61%-62%;

[0110] (3) adding 35 g of solvent (5% of the total amount) and 2.36 g of low-molecular alcohol (26% of the total amount, calculated as 100%) to the mixture after treatment in step (2), and treating at a constant temperature;

[0111] (4) adding 9.01 g of isocyanate (accounting for 17% of the total amount) to the mixture after treatment in step (3) and treating at a constant temperature;

[0112] (5) Add 0.53 g of isocyanate (1% of the total amount) to the mixture treated in step (4) and react while maintaining the R value at 0.9-1.1. Add 91 g of solvent (13% of the total amount) until the reaction viscosity reaches 10-14 Pas / 25 degrees and the solid content of the reaction solution reaches 30%-31%. Then add 0.2 g of a blocking agent, stir, and cool.

[0113] (6) Add 0.2 g of stabilizer to the mixture treated in step (5) and stir to obtain an intermediate of the polyurethane wet process resin.

[0114] Then, prepare the polyurethane wet resin, and its preparation steps are as follows:

[0115] (a) 90 g of polyester polyol PE-1 of adipic acid-ethylene glycol-1,4-butanediol system, 54 g of polyester polyol PE-2 of adipic acid-phthalic acid-ethylene glycol-1,4-butanediol system, 0.1 g of hindered phenol antioxidant accounting for 50% of the total amount, 0.0015 g of inorganic acid accounting for 50% of the total amount, and 126 g of solvent accounting for 18% of the total amount were mixed and heated;

[0116] (b) adding 5.83 g of isocyanate (11% of the total amount) to the mixture after treatment in step (a) to carry out the reaction, maintaining the R value at 0.85-0.87 and the solid content of the reaction solution at 53%-54%, and treating at a constant temperature;

[0117] (c) adding 126 g of a solvent accounting for 18% of the total amount, 6.73 g of a small molecule alcohol accounting for 74% of the total amount, and 10 g of a polyester polyol PE-5 of adipic acid-ethylene glycol system to the mixture after treatment in step (b), and treating at a constant temperature;

[0118] (d) adding 26.5 g of isocyanate (50% of the total amount) to the mixture after treatment in step (c) and treating at a constant temperature;

[0119] (e) adding 4.77 g of isocyanate (9% of the total amount) to the mixture treated in step (d) to react while maintaining the R value at 0.9-1.1, adding 287 g of solvent (41% of the total amount) until the reaction viscosity reaches 24-28 Pas / 25 degrees and the solid content of the reaction solution reaches 30%-31%, and then adding 0.2 g of a blocking agent, stirring, and cooling;

[0120] (f) adding 0.2 g of a stabilizer, a polyurethane wet process resin intermediate accounting for 24% of the total amount of the resin, and water-assisting agents XP-555 and XP-888 to the mixture after treatment in step (e) and stirring to obtain the polyurethane wet process resin.

[0121] Comparative Example 1

[0122] The preparation process is basically the same as that of Example 1, except that 3.44 g of 1,4-butanediol (denoted as 1,4-BG) is used in the intermediate chain extender instead of 2.37 g of ethylene glycol.

[0123] Comparative Example 2

[0124] The preparation process is basically the same as that of Example 1, except that 4.05 g of diethylene glycol (denoted as DEG) is used instead of 2.37 g of ethylene glycol in the intermediate chain extender.

[0125] Comparative Example 3

[0126] The preparation process is basically the same as that of Example 1, except that 1000 molecular weight polyester polyol (PE-6) is used in place of 1000 molecular weight polyester polyol (PE-5).

[0127] Comparative Example 4

[0128] The preparation process is basically the same as that of Example 1, except that a polyester polyol with a molecular weight of 4000 (denoted as PE-17) is used in the polyester polyol instead of a polyester polyol with a molecular weight of 6000 (PE-1).

[0129] The raw materials and contents of the polyurethane wet-process resins of Examples 1-3 and Comparative Examples 1-4 are shown in Table 1, unit: g.

[0130] Table 1 Raw materials and contents of polyurethane wet resins of Examples 1-3 and Comparative Examples 1-4

[0131]

[0132]

[0133] The polyurethane wet process resins of Examples 1-3 and Comparative Examples 1-4 were prepared into synthetic leather according to the following steps: 100 g of the synthesized polyurethane resin was added to a plastic bottle, 40 g of white wood powder, 1 g of oily black pulp and 110 g of DMF solvent were added thereto, and the mixture was heated at 3000 r·min. -1 The mixture was uniformly dispersed at a high speed under stirring, then allowed to stand for degassing before use. A viscose base fabric for leather was soaked in a 20% DMF aqueous solution to remove surface impurities. The fabric was then pressurized with a water press and ironed until semi-dry. A 0.2 mm thick feeler gauge was then placed on the back of the base fabric. A small amount of the slurry to be used was poured onto the back of a hydrolysis-resistant fabric and scraped onto it. The fabric was then placed in water for full solidification, followed by washing and drying. The synthetic leathers of Examples 1-3 and Comparative Examples 1-4 were thus produced.

[0134] The following performance tests were performed on the synthetic leathers of Examples 1-3 and Comparative Examples 1-4, respectively, according to the following test evaluation standards:

[0135] Color development: If the color in the coating is evenly distributed and visibly bright, it is excellent; if there is visible white, it is poor.

[0136] Heat resistance: After passing 180℃ high temperature and high pressure, if the lines are full and three-dimensional, it is excellent; if the lines are unclear or there are no lines, it is poor.

[0137] Thickness: When the resin coating is spread according to 100 lines of a fixed caliper, a thickness of 0.3 mm or more is considered excellent, and less than 0.1 mm is considered poor.

[0138] Peel strength: After drying at 110°C, the peel strength reaches 5KG, which is excellent; if it does not reach 5KG, it is poor.

[0139] Feel: If the meat feels good after being dried at a high temperature of 110℃, it is excellent; if the meat does not feel good, it is poor.

[0140] Washing: After 15 passes through the washing roller, the surface is flat and good; if the surface is uneven, it is poor. The results are shown in Table 2.

[0141] Table 2 Performance test results of different embodiments and comparative examples

[0142]

[0143] It can be seen from Table 2 that Example 1 has good color development, thickness, heat resistance, peel strength, soft and thick feel, and water washing performance, and has excellent comprehensive performance.

[0144] By comparing Example 1 with the comparative example, it can be seen that by selecting two polyester polyols with different special structures and a molecular weight of 2000 as intermediates and then combining them with the main body, the peel strength, thickness and softness of the product can be improved, especially the water washing performance is more outstanding.

[0145] A comparison of Example 1 and Example 3 shows that by using a polyester polyol with an AA-EG-BG structure and a polyester polyol with an AA-PA-EG-BG structure of the same molecular weight of 4000, combined with a special process, synthetic leather products can achieve improved softness, thickness, and peel strength. A comparison of Example 1 and Comparative Example 4 shows that by selecting a polyester polyol with a specific molecular weight of 6000 and an AA-EG-BG structure, the film-forming properties and soft feel of the synthetic leather base surface can be improved, and the peel strength is particularly significantly improved.

[0146] The technologies not specifically mentioned above are all referenced to the existing technologies.

[0147] The technical means disclosed in the solutions of the present invention are not limited to the technical means disclosed in the above technical means, but also include technical solutions composed of any combination of the above technical features. The above is a specific embodiment of the present invention. It should be noted that for those skilled in the art, various improvements and modifications can be made without departing from the principles of the present invention, and such improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A polyurethane wet process resin for soft embossing-resistant garment leather, characterized in that: The raw materials for preparation include the following components in parts by weight: 0.002-0.004 parts of inorganic acid; 165-251 parts of polyester polyol; 42-64 parts of isocyanate; 7-11 parts of small molecule alcohol; 24-37 parts of additives; 560-840 parts of solvent; the polyester polyol also includes: polyester polyol of adipic acid-ethylene glycol-1,4-butanediol system, polyester polyol of adipic acid-phthalic acid-ethylene glycol-1,4-butanediol system, polyester polyol of adipic acid-diethylene glycol-ethylene glycol system, polyester polyol of adipic acid-diethylene glycol system and polyester polyol of adipic acid-ethylene glycol system.

2. The polyurethane wet-process resin for soft embossing-resistant garment leather according to claim 1, characterized in that: The inorganic acid is concentrated phosphoric acid.

3. The polyurethane wet-process resin for soft embossing-resistant garment leather according to claim 1, characterized in that: The molecular weight of the polyester polyols of the adipic acid-ethylene glycol-1,4-butanediol system is 5800-6200, the molecular weight of the polyester polyols of the adipic acid-phthalic acid-ethylene glycol-1,4-butanediol system is 3800-4200, the molecular weight of the polyester polyols of the adipic acid-diethylene glycol system and the polyester polyols of the adipic acid-ethylene glycol-diethylene glycol system are both 1800-2200, and the molecular weight of the polyester polyols of the adipic acid-ethylene glycol system is 800-1200.

4. The polyurethane wet-process resin for soft embossing-resistant garment leather according to claim 1, characterized in that: The mass ratio of the polyester polyols of the adipic acid-ethylene glycol-1,4-butanediol system, the polyester polyols of the adipic acid-phthalic acid-ethylene glycol-1,4-butanediol system, the polyester polyols of the adipic acid-diethylene glycol-ethylene glycol system, the polyester polyols of the adipic acid-diethylene glycol system and the polyester polyols of the adipic acid-ethylene glycol system in the polyester polyols is 40-48:20-30:15-20:5-10:3-7.

5. The polyurethane wet-process resin for soft embossing-resistant garment leather according to claim 1, characterized in that: The isocyanate is one or more of diphenylmethane diisocyanate, dimethyl diphenylmethane diisocyanate, and polymethylene polyphenyl isocyanate.

6. The polyurethane wet-process resin for soft embossing-resistant garment leather according to claim 1, characterized in that: The small molecule alcohol is one or more of ethylene glycol, 1,4-butanediol, diethylene glycol, and 1,3-butanediol.

7. The polyurethane wet-process resin for soft embossing-resistant garment leather according to claim 1, characterized in that: The solvent is N,N-dimethylformamide, and the auxiliary agent is one or more of a water-assisting agent, a stabilizer, and a capping agent.

8. The polyurethane wet-process resin for soft embossing-resistant garment leather according to claim 7, characterized in that: The water-assisting detergent is polyether polyol and organosilicon auxiliary agent, the stabilizer is malic acid, and the end-capping agent is methanol.

9. The method for preparing a polyurethane wet-process resin for soft embossing-resistant garment leather according to any one of claims 1 to 8, characterized in that: The steps include: First, prepare a polyurethane wet resin intermediate, and the preparation steps are as follows: (1) The polyester polyol of the adipic acid-diethylene glycol-ethylene glycol system, the polyester polyol of the adipic acid-diethylene glycol system, 40-60% of a hindered phenol antioxidant, 40-60% of an inorganic acid, and 4-6% of a solvent are mixed and heated; (2) adding 10-14% of the total amount of isocyanate to the mixture treated in step (1) for reaction, maintaining the R value at 0.95-1.05, the reaction viscosity at 6-7 Pas / 70 degrees, and the solid content of the reaction liquid at 61%-62%; (3) adding 4-6% of the total amount of solvent and 24-28% of the total amount of small molecular alcohol to the mixture after treatment in step (2), and treating at a constant temperature; (4) adding 15-19% of the total amount of isocyanate to the mixture after treatment in step (3) and treating at a constant temperature; (5) adding 0.5-1.5% of the total amount of isocyanate to the mixture after treatment in step (4) to carry out the reaction, and maintaining the R value at 0.9-1.1, adding 10-16% of the total amount of solvent until the reaction viscosity reaches 10-14 Pas / 25 degrees and the solid content of the reaction liquid reaches 30%-31%, and then adding 40-60% of the total amount of blocking agent, stirring, and cooling; (6) adding 40-60% of a stabilizer to the mixture after treatment in step (5) and stirring to obtain the intermediate of the polyurethane wet impregnation resin; Then, prepare the polyurethane wet resin, and its preparation steps are as follows: (a) mixing a polyester polyol of an adipic acid-ethylene glycol-1,4-butanediol system, a polyester polyol of an adipic acid-phthalic acid-ethylene glycol-1,4-butanediol system, 40-60% of a hindered phenol antioxidant, 40-60% of an inorganic acid, and 16-20% of a solvent, and heating the mixture; (b) adding 10-12% of the total amount of isocyanate to the mixture after treatment in step (a) to carry out reaction, maintaining the R value at 0.85-0.87 and the solid content of the reaction solution at 53%-54%, and treating at a constant temperature; (c) adding 16-20% of a solvent and 70-78% of a low-molecular-weight alcohol to the mixture after treatment in step (b), and treating at a constant temperature; (d) adding 40-60% of the total amount of isocyanate to the mixture after treatment in step (c), and treating at a constant temperature; (e) adding the remaining 5-13% of the isocyanate to the mixture after treatment in step (d) to carry out the reaction while maintaining the R value at 0.9-1.1, adding the remaining 40-42% of the solvent until the reaction viscosity reaches 24-28 Pas / 25 degrees and the solid content of the reaction solution reaches 30%-31%, and then adding 40-60% of the blocking agent, stirring, and cooling; (f) adding 40-60% of a stabilizer, 20-28% of a polyurethane wet process resin intermediate, and a water-detergent to the mixture after treatment in step (e), and stirring to obtain the polyurethane wet process resin.

10. A synthetic leather, characterized in that: The invention is prepared by using the polyurethane wet process resin for soft embossing-resistant garment leather according to any one of claims 1 to 8, or by using the preparation method of the polyurethane wet process resin for soft embossing-resistant garment leather according to claim 9.

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