Wet-process polyurethane resin composition, mirror-surface wet-process base, mirror-surface polyurethane synthetic leather and preparation method of mirror-surface polyurethane synthetic leather

Abstract

The invention relates to the technical field of polyurethane, in particular to a wet-process polyurethane resin composition, a mirror-surface wet-process base, mirror-surface polyurethane synthetic leather and a preparation method of the mirror-surface polyurethane synthetic leather. The wet-process polyurethane resin composition comprises a main material and a cell regulator, the main material comprises 60-95% by mass of a component A and 5-40% by mass of a component B, and the cell regulator is alkane with a boiling point of 80-140 DEG C; the component A and the component B are respectively prepared from the following raw materials: polyether glycol, polyester glycol, a chain extender, an antioxidant, inorganic acid, a catalyst, diisocyanate, a solvent and an end-capping reagent. According to the wet-process polyurethane resin composition disclosed by the invention, the component A and the component B which meet a certain proportioning requirement are compounded, and mirror-surface polyurethane synthetic leather with hydrolysis resistance, good water washing performance, fine creases, low risk of separating out fog and good peeling strength can be obtained under the condition that silicone oil or other types of water promoting agents are not adopted.

Description

Technical Field

[0001] This invention relates to the field of polyurethane technology, and in particular to a wet-process polyurethane resin composition, a mirror-finish wet-process base coat, a mirror-finish polyurethane synthetic leather, and a method for preparing the same. Background Technology

[0002] Mirror-finish polyurethane synthetic leather is a type of synthetic leather with a mirror-like smooth surface and a smooth feel, widely used in bags, footwear, and other fields. Its multi-layered composite structure consists of, from the inside out, a base fabric, a wet-process resin layer, a dry-process adhesive layer, and a dry-process mirror layer. The wet-process resin layer, formed by the solidification of wet-process polyurethane slurry, is the core structure of the mirror-finish leather; the dry-process mirror layer is a mirror film with excellent color development and a crystal-like texture; the dry-process adhesive layer is used to bond the wet-process resin layer and the dry-process mirror layer.

[0003] To meet the stringent requirements of mirror-finish polyurethane synthetic leather applications, it needs to possess characteristics such as fine creases, high elasticity, high surface smoothness, good hydrolysis resistance, and low risk of fogging. Among these, the wet-process resin layer has a crucial impact on these properties. On one hand, the cell size of the wet-process resin layer directly affects the creases; generally, smaller cells result in finer creases in the synthetic leather. On the other hand, the DMF removal capability of the wet-process resin layer affects the elasticity, surface smoothness, and risk of fogging in the synthetic leather. However, when the cell size decreases, the exchange between DMF and water becomes more difficult, leading to a decrease in DMF removal capability, resulting in impaired elasticity, poorer surface smoothness, and a greater risk of fogging. Therefore, achieving mirror-finish polyurethane synthetic leather with excellent comprehensive performance has become a key technical challenge that the industry urgently needs to overcome.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a wet-process polyurethane resin composition, a mirror-finish wet-process base coat, a mirror-finish polyurethane synthetic leather, and a method for preparing the same. By controlling the composition of the wet-process polyurethane resin composition, this invention can obtain a mirror-finish polyurethane synthetic leather that combines hydrolysis resistance, good washability, fine creases, low risk of precipitation and fogging, and good peel strength.

[0006] To achieve the above-mentioned objectives of the present invention, a first aspect of the present invention provides a wet-process polyurethane resin composition comprising a main material and a cell regulator, wherein the main material comprises 60% to 95% component A and 5% to 40% component B by mass percentage; and the cell regulator is an alkane with a boiling point of 80 to 140°C.

[0007] The raw materials for component A include the following components in parts by weight: 320-400 parts of polyether diol; 0-80 parts of polyester diol; Chain extender 20-35 parts; Antioxidant 0.5 to 1 part; Inorganic acid 0-0.02 parts; Catalyst 0.02–0.04 parts; 100-180 parts of diisocyanate; Solvent: 950–1900 parts; 0-2 parts of capping agent; The raw materials for component B include the following components in parts by weight: 240-300 parts of polyether diol; 0-60 parts of polyester diol; Chain extender 40-70 parts; Antioxidant 0-2 parts; Inorganic acid 0-0.05 parts; Catalyst 0-0.08 parts; 200-260 parts of diisocyanate; Solvent: 1250–1600 parts; 0-2 parts of capping agent.

[0008] Furthermore, the 100% modulus of component A is 3.0 to 4.0 MPa.

[0009] Furthermore, the 100% modulus of component B is 8.0 to 10.0 MPa.

[0010] Furthermore, in component A, the amount of the polyester diol accounts for 5% to 15% of the total mass of the polyester diol and the polyether diol.

[0011] Furthermore, in component B, the amount of the polyester diol accounts for 5% to 15% of the total mass of the polyester diol and the polyether diol.

[0012] Furthermore, the number-average molecular weights of the polyester diols in component A and component B are each independently between 1000 and 3000.

[0013] Furthermore, the polyester diols in component A and component B are each independently selected from at least one of sebacic acid polyester diol and sebacic acid polyester diol.

[0014] Furthermore, the polyether diols in component A and component B are each independently selected from at least one of polytetrahydrofuran diol, polypropylene glycol, and ethylene glycol.

[0015] Furthermore, the number-average molecular weights of the polyether diols in component A and component B are each independently between 1000 and 4000.

[0016] Furthermore, in component A, the polyoxypropylene glycol accounts for 70% to 100% of the total mass of the polyether diol, preferably 80% to 100%.

[0017] Furthermore, in component B, the polyoxypropylene glycol accounts for 60% to 100% of the total mass of the polyether diol, preferably 80% to 100%.

[0018] Furthermore, the diisocyanates in component A and component B are each independently selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, and carbodiimide-modified diisocyanate.

[0019] Furthermore, the chain extenders in component A and component B are each independently selected from at least one of ethylene glycol, 1,4-butanediol, and diethylene glycol.

[0020] Furthermore, the solvent in component A and component B is N,N-dimethylformamide.

[0021] Furthermore, the capping agents in component A and component B are each independently selected from at least one of methanol, ethanol, and isopropanol.

[0022] Furthermore, the pore-conditioning agent includes at least one of n-heptane and n-octane.

[0023] Furthermore, the amount of the pore regulator is 0.5% to 3% of the total mass of component A and component B.

[0024] The second aspect of the present invention provides a method for preparing the wet-process polyurethane resin composition of the first aspect of the present invention, comprising the following steps: mixing and stirring component A, component B and a cell regulator at 70-80°C; The preparation of component A includes: (a1) A polyether diol, a portion of an optional polyester diol (e.g., 50% to 80% of the total mass of the polyester diol), an optional inorganic acid, an antioxidant, and a portion of a solvent are mixed together, and a portion of a diisocyanate is added to the mixture to carry out a polymerization reaction. (a2) Mix the materials from the polymerization reaction in step (a1), the chain extender, and part of the solvent, and carry out the polymerization reaction; (a3) Add some diisocyanate to the material after the polymerization reaction in step (a2) and carry out the polymerization reaction; (a4) The material after the polymerization reaction in step (a3), the remaining optional polyester diol, the remaining diisocyanate, the catalyst and the remaining solvent are mixed and subjected to polymerization reaction. When the viscosity of the system reaches the standard, an end-capping agent is optionally added for end-capping to obtain component A. The preparation of component B includes: (b1) A polyether diol, a portion of a chain extender, an optional inorganic acid, an optional antioxidant, and a portion of a solvent are mixed together, and a portion of a diisocyanate is added and mixed to carry out a polymerization reaction; (b2) The material after the polymerization reaction in step (b1), optional polyester diol, remaining chain extender and part of solvent are mixed and subjected to polymerization reaction; (b3) The material after polymerization reaction in step (b2), the remaining diisocyanate, the optional catalyst and the remaining solvent are mixed and subjected to polymerization reaction. When the viscosity of the system reaches the target, an end-capping agent is optionally added to end-cap the system to obtain component B.

[0025] Further, in step (a1), the addition of a portion of diisocyanate mixes the system to make the isocyanate index 1.8 to 2.2.

[0026] Further, in step (a3), the addition of a portion of diisocyanate makes the isocyanate index in the system 0.90 to 0.95.

[0027] Further, in step (b1), the addition of a portion of diisocyanate mixes the system to make the isocyanate index 1.5 to 1.7.

[0028] Furthermore, in step (b1), the amount of chain extender used is 18% to 22% of the total amount of chain extender.

[0029] Further, in step (a1), the polymerization reaction temperature is 70-80°C, and the polymerization reaction time is 1-2 hours.

[0030] Further, in step (a2), the polymerization reaction temperature is 70-80°C, and the polymerization reaction time is 0.4-0.6 h.

[0031] Furthermore, in step (a3), the polymerization reaction temperature is 70–80°C, and the polymerization reaction time is 1–2 hours.

[0032] Furthermore, in step (a4), the temperature of the polymerization reaction is 70–80°C.

[0033] Furthermore, in step (a4), the viscosity of the system after the polymerization reaction is 240–300 Pa·s / 25°C, and the solid content is 25%–35%.

[0034] Further, in step (b1), the polymerization reaction temperature is 70-80°C, and the polymerization reaction time is 1-2 hours.

[0035] Further, in step (b2), the polymerization reaction temperature is 70-80°C, and the polymerization reaction time is 0.4-0.6 h.

[0036] Furthermore, in step (b3), the polymerization reaction is carried out at a temperature of 70–80°C.

[0037] Furthermore, in step (b3), the viscosity of the system after the polymerization reaction is 100-160 Pa·s / 25℃, and the solid content is 25%-35%.

[0038] A third aspect of the present invention provides a mirror-finish wet-process base fabric, comprising a base fabric and a wet-process resin layer; the wet-process resin layer is mainly made of wet-process slurry; The wet slurry comprises the following components by weight: 100 parts of the wet-process polyurethane resin composition of the first aspect of the present invention; 50-70 parts of filler; 0-2 parts of color paste; Solvent 60-80 parts.

[0039] The fourth aspect of the present invention provides a method for preparing a mirror wet-process base coat according to the third aspect of the present invention, comprising the following steps: coating a wet slurry onto the surface of a pretreated base fabric, then coagulating it in a coagulation bath, and then washing and drying it to obtain the mirror wet-process base coat.

[0040] Furthermore, the coagulation bath is a DMF aqueous solution with a sugar content of 14% to 18%.

[0041] The fifth aspect of the present invention provides a mirror-finish polyurethane synthetic leather, comprising, in sequence, a mirror-finish wet-laid base layer, an adhesive layer, and a mirror layer; The mirror wet base layer is made from the mirror wet base provided in the third aspect of the present invention.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows: The wet-process polyurethane resin composition of the present invention uses a compound of component A and component B in a certain ratio, and introduces a cell regulator to adjust the interaction between component A and component B, further improving coagulation uniformity and peel strength. Without using silicone oil or other types of wash-promoting agents, a mirror-finish polyurethane synthetic leather with hydrolysis resistance, good washability, fine creases, low risk of precipitation fogging, and good peel strength can be obtained. Attached Figure Description

[0043] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0044] Figure 1 This is an optical microscope image of the crease of a mirror-finished polyurethane synthetic leather sample after folding, according to Example 1 of the present invention. Figure 2 This is an optical microscope image of the crease of a mirror-finished polyurethane synthetic leather sample after folding, as described in Example 4 of this invention. Figure 3 This is an optical microscope image of the crease of a mirror-finished polyurethane synthetic leather sample after folding, as described in Example 10 of the present invention. Detailed Implementation

[0045] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0046] The first aspect of the present invention provides a wet-process polyurethane resin composition comprising a main ingredient and a cell regulator, wherein the main ingredient comprises 60% to 95% by mass of component A and 5% to 40% by mass of component B; and the cell regulator is an alkane with a boiling point of 80 to 140°C.

[0047] The raw materials for component A include the following components by weight: 320-400 parts of polyether diol; 0-80 parts of polyester diol; Chain extender 20-35 parts; Antioxidant 0.5 to 1 part; Inorganic acid 0-0.02 parts; Catalyst 0.02–0.04 parts; 100-180 parts of diisocyanate; Solvent: 950–1900 parts; 0-2 parts of capping agent; The raw materials for component B include the following components by weight: 240-300 parts of polyether diol; 0-60 parts of polyester diol; Chain extender 40-70 parts; Antioxidant 0-2 parts; Inorganic acid 0-0.05 parts; Catalyst 0-0.08 parts; 200-260 parts of diisocyanate; Solvent: 1250–1600 parts; 0-2 parts of capping agent.

[0048] The wet-process polyurethane resin composition of the present invention uses a compound of component A and component B in a certain ratio, and introduces a cell regulator to adjust the interaction between component A and component B, further improving coagulation uniformity and peel strength. Without using silicone oil or other types of wash-promoting agents, a mirror-finish polyurethane synthetic leather with hydrolysis resistance, good washability, fine creases, low risk of precipitation fogging, and good peel strength can be obtained.

[0049] The washability of polyurethane mainly depends on water diffusion and the cohesive force of polyurethane. Component B of this invention has a high modulus; when compounded with component A, which has a low modulus, it increases the cohesive force of the polyurethane and enhances the cohesive force, making the polyurethane-water-DMF three-phase separation easier and the DMF easier to remove. Furthermore, the introduction of component B provides more coagulation nucleation sites, improving coagulation uniformity, resulting in more complete and uniform coagulation of the mixed resin. This effectively enhances the DMF removal capability, accelerates the coagulation rate, controls the cell size to be small, improves surface smoothness, and enhances support. Due to the improved DMF removal capability, coagulation can be accelerated and water washing enhanced without the use of a water-washing accelerator, reducing the risk of precipitation and fogging. In addition, the requirements for component A in terms of DMF removal capability and coagulation rate performance can be reduced, thereby broadening the selection range of component A.

[0050] The wet-process polyurethane resin composition also includes a cell regulator, which is an alkane with a boiling point of 80–140°C. Specifically, the boiling point of the cell regulator can be within the range of 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, or any combination thereof. The cell regulator introduced into the resin composition by this invention has hydrophobic properties, which can coordinate the interaction between component A and component B, improving solidification uniformity and peel strength. Furthermore, the boiling point of the cell regulator is lower than the temperature during resin drying, allowing it to be fully removed during the drying process and preventing later precipitation.

[0051] In different embodiments, the amount of component A in the wet-process polyurethane resin composition, by mass percentage, can be 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or any combination thereof; the amount of component B can be 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, or any combination thereof. Adjusting the amounts of components A and B within the above ranges can balance their DMF removal ability and cell size, improve the surface smoothness, elasticity, and support of the resin layer, and prevent fogging. When the content of component B is too high, the cell size is too large; when the content of component B is too low, the improvement in DMF removal ability is insufficient, easily leading to fogging and unevenness of the resin layer, and poor elasticity.

[0052] In a specific embodiment of the present invention, the 100% modulus of component A is 3.0 to 4.0 MPa, such as a range of 3.0 MPa, 3.2 MPa, 3.5 MPa, 3.8 MPa, 4.0 MPa, or any two of them.

[0053] In a specific embodiment of the present invention, the 100% modulus of component B is 8.0 to 10.0 MPa, such as a range of 8.0 MPa, 8.2 MPa, 8.5 MPa, 8.8 MPa, 9.0 MPa, 9.2 MPa, 9.5 MPa, 9.8 MPa, 10.0 MPa, or any combination thereof.

[0054] In a specific embodiment of the present invention, in component A, the amount of polyether diol is 320 to 400 parts by weight, specifically 320 parts, 340 parts, 360 parts, 380 parts, 400 parts, or any combination thereof; the amount of polyester diol is 0 to 80 parts, specifically 0 parts, 20 parts, 40 parts, 60 parts, 80 parts, or any combination thereof.

[0055] In a specific embodiment of the present invention, in component B, the amount of polyether diol is 240 to 300 parts by weight, specifically 240 parts, 250 parts, 260 parts, 270 parts, 280 parts, 290 parts, 300 parts, or any combination thereof; the amount of polyester diol is 0 to 60 parts, specifically 0 parts, 10 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, or any combination thereof.

[0056] In a specific embodiment of the present invention, in component A, the amount of polyester diol accounts for 5% to 15% of the total mass of polyester diol and polyether diol, specifically it can be 5%, 8%, 10%, 12%, 15% or any combination thereof.

[0057] In a specific embodiment of the present invention, in component B, the amount of polyester diol accounts for 5% to 15% of the total mass of polyester diol and polyether diol, specifically it can be 5%, 8%, 10%, 12%, 15% or any combination thereof.

[0058] The appropriate introduction of polyester diol into component A and / or component B is beneficial to improving the resin's DMF removal ability and solidification uniformity, and avoiding excessively large cells. Excessive introduction of polyester diol will reduce the resin's hydrolysis resistance; insufficient polyester diol will reduce both the resin's DMF removal ability and solidification uniformity.

[0059] In a specific embodiment of the present invention, the number average molecular weight of the polyester diols in component A and component B is independently 1000 to 3000, such as 1000, 1200, 1500, 1800, 2000, 2200, 2500, 2800, 3000 or any combination thereof.

[0060] In a specific embodiment of the present invention, the polyester diols in component A and component B are each independently selected from at least one of sebacic acid polyester diol and sebacic acid polyester diol.

[0061] The polyester diols used include, but are not limited to, one or more of ethylene glycol, 1,4-butanediol, 1,3-propanediol, diethylene glycol, neopentyl glycol, and 1,6-hexanediol. For example, the polyester diols in components A and B are each independently selected from polybutylene adipate diol, polyhexyl adipate diol, polyhexyl sebacate diol, and polyneoprene adipate diol. Furthermore, using crystalline polyester polyols is more beneficial for improving the resin's coagulation kinetics, promoting internal coagulation, and enhancing coagulation uniformity.

[0062] In a specific embodiment of the present invention, the polyether diols in component A and component B are each independently selected from at least one of polytetrahydrofuran diol, polypropylene glycol, and ethylene glycol.

[0063] In a specific embodiment of the present invention, the number average molecular weight of the polyether diols in component A and component B is independently 1000 to 4000, such as 1000, 1500, 2000, 2500, 3000, 3500, 4000 or any combination thereof.

[0064] In a specific embodiment of the present invention, in component A, polyoxypropylene glycol accounts for 70% to 100% of the total mass of the polyether diol, such as a range of 70%, 75%, 80%, 85%, 90%, 95%, 100% or any two thereof, preferably 80% to 100%.

[0065] In a specific embodiment of the present invention, in component B, polyoxypropylene glycol accounts for 60% to 100% of the total mass of polyether diol, such as 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100% or any two of these ranges, preferably 80% to 100%.

[0066] Polypropylene oxide glycol has weak crystallinity and weak solidification kinetics. Adjusting the proportion of polypropylene oxide glycol in polyether diols in component A and / or component B helps to stabilize the cell structure.

[0067] In a specific embodiment of the present invention, the amount of diisocyanate in component A is 100 to 180 parts by weight, specifically 100 parts, 120 parts, 140 parts, 160 parts, 180 parts, or any combination thereof.

[0068] In a specific embodiment of the present invention, the amount of diisocyanate in component B, by weight, is 200 to 260 parts, specifically 200 parts, 210 parts, 220 parts, 230 parts, 240 parts, 250 parts, 260 parts, or any combination thereof.

[0069] In a specific embodiment of the present invention, the diisocyanates in component A and component B are each independently selected from at least one of toluene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), and carbodiimide-modified diisocyanate.

[0070] In a specific embodiment of the present invention, the amount of chain extender in component A, by weight, is 20 to 35 parts, specifically 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts, or any combination thereof.

[0071] In a specific embodiment of the present invention, the amount of chain extender in component B, by weight, is 40 to 70 parts, specifically 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, or any combination thereof.

[0072] In a specific embodiment of the present invention, the chain extenders in component A and component B are each independently selected from at least one of ethylene glycol, 1,4-butanediol and diethylene glycol.

[0073] In a specific embodiment of the present invention, the amount of solvent in component A, by weight, is 950 to 1900 parts, specifically 950 parts, 1000 parts, 1100 parts, 1200 parts, 1250 parts, 1300 parts, 1350 parts, 1400 parts, 1500 parts, 1600 parts, 1700 parts, 1800 parts, 1900 parts, or any combination thereof.

[0074] In a specific embodiment of the present invention, the amount of solvent used in component B, by weight, is 1250 to 1600 parts, specifically 1250 parts, 1300 parts, 1350 parts, 1400 parts, 1450 parts, 1500 parts, 1600 parts, or any combination thereof.

[0075] In a specific embodiment of the present invention, the solvent in components A and B is N,N-dimethylformamide.

[0076] In a specific embodiment of the present invention, the amount of capping agent in component A, by weight, is 0 to 2 parts, specifically 0 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, or any combination thereof, preferably 0.1 to 0.5 parts.

[0077] In a specific embodiment of the present invention, the amount of the capping agent in component B, by weight, is 0 to 2 parts, specifically 0 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, or any combination thereof, preferably 0.2 to 0.8 parts.

[0078] In a specific embodiment of the present invention, the capping agents in component A and component B are each independently selected from at least one of methanol, ethanol and isopropanol.

[0079] In a specific embodiment of the present invention, in component A, the amount of antioxidant is 0.5 to 1 part by weight, specifically 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, or any combination thereof; the amount of inorganic acid is 0 to 0.02 parts, specifically 0 parts, 0.01 parts, 0.015 parts, 0.02 parts, or any combination thereof, preferably 0.003 to 0.008 parts.

[0080] In a specific embodiment of the present invention, in component B, the amount of antioxidant is 0 to 2 parts by weight, specifically 0 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, or any combination thereof, preferably 0.5 to 1 part; the amount of inorganic acid is 0 to 0.05 parts, specifically 0 parts, 0.01 parts, 0.02 parts, 0.03 parts, 0.04 parts, 0.05 parts, or any combination thereof, preferably 0.01 to 0.02 parts.

[0081] In a specific embodiment of the present invention, the antioxidants in component A and component B are each independently selected from at least one of antioxidant 1790, antioxidant 1135, antioxidant 1010 and antioxidant 168; the inorganic acid in component A and component B is a polymerization inhibitor (such as phosphoric acid).

[0082] In a specific embodiment of the present invention, the amount of catalyst in component A is 0.02 to 0.04 parts by weight, specifically 0.02 parts, 0.025 parts, 0.03 parts, 0.035 parts, 0.04 parts, or any combination thereof.

[0083] In a specific embodiment of the present invention, the amount of catalyst in component B, by weight, is 0 to 0.08 parts, specifically 0 parts, 0.02 parts, 0.04 parts, 0.06 parts, 0.08 parts, or any combination thereof, preferably 0.01 to 0.02 parts.

[0084] In a specific embodiment of the present invention, the catalysts in component A and component B are organic bismuth polyurethane catalysts, such as, but not limited to, BiCAT 8108.

[0085] It should be noted that the antioxidants, polymerization inhibitors (such as phosphoric acid), catalysts, and end-capping agents used in this invention are all common knowledge and existing technologies in the field. For example, antioxidants are used in the polyurethane field to inhibit oxidative yellowing of materials (such as antioxidant 168), polymerization inhibitors (such as phosphoric acid) are used to control the reaction process, and catalysts are used to promote chain extension reactions. The selection and application of such additives have been widely described in domestic and international published technical literature. Those skilled in the art can reasonably select the type, ratio, and stage of use of additives based on conventional knowledge, and their application will not have a substantial impact on the innovative core process of this invention.

[0086] In a specific embodiment of the present invention, the pore-conditioning agent includes at least one of n-heptane and n-octane, preferably n-heptane.

[0087] In a specific embodiment of the present invention, the amount of the bubble conditioner is 0.5% to 3% of the total mass of component A and component B, specifically 0.5%, 1%, 1.5%, 2%, 2.5%, 3% or any combination thereof.

[0088] The second aspect of the present invention provides a method for preparing a wet-process polyurethane resin composition according to the first aspect of the present invention, comprising the following steps: mixing and stirring component A, component B and a cell regulator at 70-80°C.

[0089] In a specific embodiment of the present invention, component B is prepared first. After the viscosity of the system of component A reaches the standard, component A is left in the reaction vessel, component B is added directly to the reaction vessel, and then a bubble conditioner is added to carry out the reaction.

[0090] In a specific embodiment of the present invention, the preparation of component A includes: (a1) A polyether diol, a portion of an optional polyester diol, an optional inorganic acid, an antioxidant, and a portion of a solvent are mixed together, and a portion of a diisocyanate is added and mixed to carry out a polymerization reaction; (a2) Mix the materials from the polymerization reaction in step (a1), the chain extender, and part of the solvent, and carry out the polymerization reaction; (a3) Add some diisocyanate to the material after the polymerization reaction in step (a2) and carry out the polymerization reaction; (a4) The material after the polymerization reaction in step (a3), the remaining optional polyester diol, the remaining diisocyanate, the catalyst and the remaining solvent are mixed and subjected to polymerization reaction. When the viscosity of the system reaches the standard, an end-capping agent is optionally added to end-cap the system to obtain component A.

[0091] The preparation of component A in this invention employs a three-step method, combining an excess method (where the isocyanate index is greater than 1) and a deficient method (where the isocyanate index is less than 1) to achieve more uniform resin coagulation, more regular cell structure, and superior washability. Specifically, the first step uses an excess method with a high isocyanate index (i.e., maintaining an isocyanate index of 1.8–2.2 in step a1) to ensure uniform distribution of the polyol and chain extender, thereby providing uniform coagulation kinetics in each region. The second step uses a deficient method with a high isocyanate index for prepolymerization (i.e., maintaining an isocyanate index of 0.90–0.95 in step a3), using polyester polyol to connect and extend the chain, promoting coagulation and washability in each region. The third step yields component A with an isocyanate index of approximately 1, uniform coagulation, and a certain degree of washability.

[0092] In a specific embodiment of the present invention, in step (a1), a portion of diisocyanate is added to mix the system so that the isocyanate index is 1.8 to 2.2.

[0093] In a specific embodiment of the present invention, in step (a3), a portion of diisocyanate is added to make the isocyanate index in the system 0.90 to 0.95.

[0094] In a specific embodiment of the present invention, in step (a1), the polymerization temperature is 70-80°C and the polymerization time is 1-2 hours.

[0095] In a specific embodiment of the present invention, in step (a2), the polymerization temperature is 70-80°C and the polymerization time is 0.4-0.6 h.

[0096] In a specific embodiment of the present invention, in step (a3), the polymerization temperature is 70-80°C and the polymerization time is 1-2 hours.

[0097] In a specific embodiment of the present invention, in step (a4), the temperature of the polymerization reaction is 70-80°C.

[0098] In a specific embodiment of the present invention, in step (a4), the viscosity of the system after the polymerization reaction is 240-300 Pa·s / 25℃, and the solid content is 25%-35%.

[0099] In a specific embodiment of the present invention, the preparation of component B includes: (b1) A polyether diol, a portion of a chain extender, an optional inorganic acid, an optional antioxidant, and a portion of a solvent are mixed together, and a portion of a diisocyanate is added and mixed to carry out a polymerization reaction; (b2) The material after the polymerization reaction in step (b1), optional polyester diol, remaining chain extender and part of solvent are mixed and subjected to polymerization reaction; (b3) The material after polymerization reaction in step (b2), the remaining diisocyanate, the optional catalyst and the remaining solvent are mixed and subjected to polymerization reaction. When the viscosity of the system reaches the target, an end-capping agent is optionally added to end-cap the system to obtain component B.

[0100] Component B employs an excess method with a low isocyanate index (i.e., an isocyanate index of 1.5–1.7 in step b1). The higher prepolymerization degree results in a more concentrated soft and hard segment of the resin, and the microphase separation provides better coagulation kinetics and washability. Simultaneously, a portion of the chain extender is added to the early prepolymerization stage and the polyester polyol in the second step. Small amounts of hard and soft segments are then incorporated into the concentrated soft and hard segments respectively, coarsening the overall coagulation and preventing excessively rapid coagulation that would lead to overly large cells and coarse creases.

[0101] In a specific embodiment of the present invention, in step (b1), a portion of diisocyanate is added to mix the system so that the isocyanate index is 1.5 to 1.7.

[0102] In a specific embodiment of the present invention, in step (b1), the amount of a portion of the chain extender is 18% to 22% of the total amount of the chain extender.

[0103] In a specific embodiment of the present invention, in step (b1), the polymerization temperature is 70-80°C and the polymerization time is 1-2 hours.

[0104] In a specific embodiment of the present invention, in step (b2), the polymerization temperature is 70-80°C and the polymerization time is 0.4-0.6 h.

[0105] In a specific embodiment of the present invention, in step (b3), the polymerization reaction temperature is 70-80°C.

[0106] In a specific embodiment of the present invention, in step (b3), the viscosity of the system after the polymerization reaction is 100-160 Pa·s / 25℃, and the solid content is 25%-35%.

[0107] A third aspect of the present invention provides a mirror-finish wet-process base fabric, comprising a base fabric and a wet-process resin layer; the wet-process resin layer is mainly made of wet-process slurry; Wet slurry comprises the following components by weight: 100 parts of the wet-process polyurethane resin composition of the first aspect of the present invention; 50-70 parts of filler; 0-2 parts of color paste; Solvent 60-80 parts.

[0108] In different embodiments, relative to 100 parts by weight of the wet-process polyurethane resin composition, the amount of filler can be 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, or any combination thereof; the amount of color paste can be 0 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, or any combination thereof; and the amount of solvent can be 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, or any combination thereof.

[0109] The fourth aspect of the present invention provides a method for preparing a mirror wet-process base coat according to the third aspect of the present invention, comprising the following steps: coating a wet slurry onto the surface of a pretreated base fabric, then coagulating it in a coagulation bath, and then washing and drying it to obtain a mirror wet-process base coat.

[0110] In a specific embodiment of the present invention, the coagulation bath is a DMF aqueous solution with a sugar content of 14% to 18%, such as a sugar content of 14%, 15%, 16%, 17%, 18%, or any combination thereof. The sugar content is measured by a handheld refractometer (saccharimeter). A specific testing method may include: after cleaning the refractometer prism, adding 0.2 to 0.3 mL of the liquid to be tested, closing the cover and allowing it to stand for 10 to 20 seconds to stabilize the temperature, observing the blue-white boundary line through the eyepiece; the scale value is the sugar content.

[0111] In a specific embodiment of the present invention, the pretreatment of the base fabric includes: immersing the base fabric in a DMF aqueous solution with a sugar content of 14% to 18%, and then squeezing out the excess solution using a pressure roller; then drying the base fabric in an oven at 130 to 150°C for 10 to 20 seconds.

[0112] In practice, the coating method of the present invention is not limited and can be roller coating, blade coating or dip coating, etc.

[0113] The fifth aspect of the present invention provides a mirror-finish polyurethane synthetic leather, comprising, in sequence, a mirror-finish wet-laid base layer, an adhesive layer, and a mirror layer; The mirror wet-laid base layer is made from the mirror wet-laid base layer provided in the third aspect of the present invention.

[0114] In a specific embodiment of the invention, the mirror layer is mainly made of dry-process mirror surface layer slurry. Specifically, the dry-process mirror surface layer slurry is coated onto mirror release paper according to the required coating thickness, and baked at 120-140°C for 3-5 minutes to obtain the mirror layer. Further, after coating the mirror layer with adhesive slurry, it is attached to the mirror wet-process base layer, baked at 120-140°C for 5-8 minutes, and the release paper is removed to obtain mirror polyurethane synthetic leather.

[0115] In a specific embodiment of the invention, the dry-process mirror surface layer slurry comprises the following components by weight: 100 parts dry-process mirror resin, 80-100 parts DMF, and 4-8 parts carbon black. Further, the preparation of the dry-process mirror surface layer slurry includes: mixing the dry-process mirror resin, DMF, and carbon black in proportion, dispersing them uniformly at high speed using a bench drill, and then degassing.

[0116] In a specific embodiment of the present invention, the adhesive layer slurry comprises the following components by weight: 100 parts of dry adhesive layer resin, 80-100 parts of DMF, and 4-8 parts of carbon black. Further, the preparation of the adhesive layer slurry includes: mixing the dry adhesive layer resin, DMF, and carbon black in proportion, dispersing them uniformly at high speed using a bench drill, and then degassing.

[0117] Source of raw materials The specific sources of raw materials in the examples are as follows; those not mentioned are all conventional products in the polyurethane industry: Polypropylene glycol, number average molecular weight 1000 g / mol, Dow Chemical (China) Co., Ltd. Polypropylene glycol, number average molecular weight 2000 g / mol, Dow Chemical (China) Co., Ltd. Polypropylene glycol, number average molecular weight 4000 g / mol, Jiahe Chemical Co., Ltd.; Polytetrahydrofuran diol, number average molecular weight 1000 g / mol, BASF (China) Co., Ltd. Polytetrahydrofuran diol, number average molecular weight 2000 g / mol, BASF (China) Co., Ltd. Polyhexanediol adipate and polybutylene adipate both originate from Zhejiang Huafeng New Materials Co., Ltd. Phosphoric acid is 85 wt%, industrial grade phosphoric acid.

[0118] The test method for the 100% modulus of components A and B in the following examples includes: the components to be tested are made into films on mirror release paper using a 15-filament film maker, cured in an oven at 135-145°C (e.g., 140°C) for 5 minutes, peeled off from the release paper, and left at room temperature for 24 hours. The 100% modulus is then tested according to standard GB / T1040.3-2006.

[0119] Examples 1-11 The method for preparing the wet-process polyurethane resin composition of the embodiment includes the following steps: (1) Preparation of component A: Mix 66% of the total mass of polyether diol and polyester diol, inorganic acid, antioxidant and part of solvent evenly, add part of isocyanate, control the isocyanate index to 2.0, and keep warm at 75±2℃ for 1.5 hours. Add chain extender and part of solvent, and keep warm at 75±2℃ for 30 minutes; Add a portion of isocyanate, control the isocyanate index to 0.95, and keep warm at 75±2℃ for 1.5 hours; The remaining polyester diol and remaining isocyanate were added, along with a catalyst. The mixture was allowed to expand and thicken at 75±2℃. The viscosity of the reaction solution was adjusted to 270±30 Pa·s / 25℃ by continuously adding the remaining solvent. The solid content of the reaction solution was 30%±1%. After adding the end-capping agent and stirring, component A was obtained.

[0120] (2) Preparation of component B: Mix polyether diol, 20% of the weight of chain extender, inorganic acid, antioxidant and part of solvent evenly, add part of isocyanate, control the isocyanate index to 1.6, and keep warm at 75±2℃ for 1.5 hours. Add polyester diol, the remaining chain extender, and part of the solvent, and keep warm at 75±2℃ for 30 minutes; Add the remaining isocyanate and catalyst, and allow it to expand and thicken at 75±2℃. Adjust the viscosity of the reaction solution to 130±30Pa·s / 25℃ by continuously adding the remaining solvent. The solid content of the reaction solution is 30%±1%. After adding the end-capping agent and stirring, component B is obtained.

[0121] (3) Preparation of wet-process polyurethane resin composition: After the preparation of component A is completed, it remains in the reactor at 75±2℃. Component B is added in proportion and stirred for 30 minutes. Then, a cell conditioner is added, and the mixture is stirred at 75±2℃ for 30 minutes to obtain a wet-process polyurethane resin composition with a viscosity of 160~300Pa·s / 25℃.

[0122] The method for preparing the mirror-finish wet-laid bass in this embodiment includes the following steps: Take 100g of the above-synthesized polyurethane resin composition and add it to a plastic bottle. Add 60g of calcium carbonate, 1g of oily black paste and 70g of solvent DMF. Disperse the mixture evenly at high speed using a bench drill and degas it for 3 minutes using a degassing machine to obtain a wet slurry.

[0123] The base fabric was soaked in a 16% sugar concentration DMF aqueous solution to moisten it, and then the excess solution was squeezed out using a pressure roller. The base fabric was then dried at 140°C for 15 seconds. A wet slurry was applied to the base fabric using a 100-filament coating rod, and then placed in a 16% sugar concentration DMF aqueous solution to solidify for 8 minutes. After solidification, the fabric was removed, washed with water, and dried to obtain a mirror-finish wet-process base layer. The drying conditions were 140°C for 20 minutes.

[0124] The method for preparing mirror-finish polyurethane synthetic leather in this embodiment includes the following steps: A dry-process mirror surface layer slurry is coated onto a mirror release paper with a coating thickness of 15 mils. The mixture is then baked at 130°C for 4 minutes to obtain a mirror layer. A dry-process adhesive layer slurry is then coated onto the mirror layer with a coating thickness of 15 mils. The mixture is then attached to the aforementioned wet-process mirror base layer and baked at 135°C for 6 minutes. The release paper is then removed to obtain mirror polyurethane synthetic leather.

[0125] The dry-process mirror finish slurry was prepared by mixing 100g of dry-process mirror resin, 90g of DMF, and 5g of carbon black, dispersing the mixture evenly using a bench drill at high speed, and then degassing it for 3 minutes using a degassing machine. The dry-process mirror resin was JF-S-8118 from Zhejiang Huafeng Synthetic Resin Co., Ltd.

[0126] The dry bonding layer slurry was prepared by mixing 100g of dry bonding layer resin, 90g of DMF, and 5g of carbon black, dispersing the mixture evenly using a bench drill at high speed, and then degassing it for 3 minutes using a degassing machine. The dry bonding layer resin was JF-A-5052 from Zhejiang Huafeng Synthetic Resin Co., Ltd.

[0127] The raw material composition information of the wet-process polyurethane resin compositions of Examples 1 to 11 is shown in Tables 1 to 2.

[0128] Table 1. Information on each component in Examples 1-6 (measured in g).

[0129] Note: If the corresponding substance is not present, it can be omitted from the preparation method.

[0130] Table 2. Information on each component in Examples 7-11 (measured in g).

[0131] Example 12 Example 12 refers to the preparation method of the wet polyurethane resin composition, mirror wet-process base and mirror polyurethane synthetic leather of Example 1, the only difference being that the mass ratio of component A to component B in the wet polyurethane resin composition is different, and the rest is the same as in Example 1.

[0132] In this embodiment, the mass ratio of component A to component B is 60:40.

[0133] Example 13 Example 13 refers to the preparation method of the wet-process polyurethane resin composition, mirror wet-process base and mirror polyurethane synthetic leather of Example 1, the only difference being that the mass ratio of component A to component B in the wet-process polyurethane resin composition is different, and the rest is the same as in Example 1.

[0134] In this embodiment, the mass ratio of component A to component B is 95:5.

[0135] Comparative Examples 1-6 The preparation methods of the wet-process polyurethane resin composition, mirror wet-process base, and mirror polyurethane synthetic leather in Comparative Examples 1 to 6 refer to Example 1, differing only in the raw material component information of the wet-process polyurethane resin composition.

[0136] The raw material composition information of the wet-process polyurethane resin compositions of Comparative Examples 1 to 6 is shown in Table 3.

[0137] Table 3 Information on each component of Comparative Examples 1–6 (amount in g).

[0138] Comparative Example 7 Comparative Example 7 refers to the preparation methods of the wet-process polyurethane resin composition, mirror wet-process base, and mirror polyurethane synthetic leather in Example 1, the only difference being that no cell regulator is added in the preparation of the wet-process polyurethane resin composition.

[0139] Comparative Example 8 Comparative Example 8 refers to the preparation methods of the wet-process polyurethane resin composition, mirror wet-process base, and mirror polyurethane synthetic leather of Example 1. The only difference is that the mass ratio of component A to component B in the wet-process polyurethane resin composition is different, and all other aspects are the same as in Example 1.

[0140] In this comparative example, the mass ratio of component A to component B is 55:45.

[0141] Comparative Example 9 Comparative Example 9 refers to the preparation methods of the wet-process polyurethane resin composition, mirror wet-process base, and mirror polyurethane synthetic leather of Example 1. The only difference is that the mass ratio of component A to component B in the wet-process polyurethane resin composition is different, and all other aspects are the same as in Example 1.

[0142] In this comparative example, the mass ratio of component A to component B is 97:3.

[0143] Experimental Example The samples prepared in different embodiments and comparative examples were tested as follows, and the test results are shown in Table 4.

[0144] 1. Bubble test Take a sample of the mirror-finished wet-process base layer and observe the cross-section of the wet-process base layer using an optical microscope. Randomly select 20 cells within the same area and measure the cell diameter (the maximum distance between two points from the center of the cell to the edge of the cell). Take the average value as the average cell size D. If the average cell size D satisfies D < 30 μm, it is rated as excellent. If the average cell size D satisfies 30 μm ≤ D < 30 μm < 40 μm, it is rated as medium. If the average cell size D satisfies D > 40 μm, it is rated as poor.

[0145] 2. Smoothness after washing Take a sample of the mirror-finish wet-process base layer, squeeze and wash it 15 times with water using a pressure roller, then place it in a 140℃ oven for 20 minutes and observe the base surface with the naked eye; if the surface is flat, it is recorded as excellent; if the surface is slightly uneven, it is recorded as medium; if the surface is uneven, it is recorded as poor.

[0146] 3. Peel strength Take a sample of the mirror-finished wet-laid base layer and test the peel strength X of the 3cm wide wet-laid base layer using a tensile testing machine. If X satisfies X≥4kg / 3cm, it is recorded as excellent; if X satisfies 3kg / 3cm≤X<4kg / 3cm, it is recorded as average; if X satisfies X<3kg / 3cm, it is recorded as poor.

[0147] 4. Hydrolysis resistance Take a sample of the mirror-finished wet-process base layer and test the initial peel strength X according to the method in section 3. Then, soak the sample in a 10wt% NaOH aqueous solution at 25℃ for 24 hours. Take out the sample, repeatedly wash and squeeze it with water to remove the NaOH, and then dry it. Test the peel strength X' after washing according to the method in section 3. Calculate the peel strength attenuation rate α according to (X-X') / X. If α satisfies α<10%, it is recorded as excellent; if α satisfies 10%≤α<20%, ​​it is recorded as medium; if α satisfies α≥20%, it is recorded as poor.

[0148] 5. Crease test Take a sample of mirror-finish polyurethane synthetic leather, fold the dry mirror-finish side of the sample inwards, and unfold it. If the creases are fine and shallow, it indicates good crease resistance; if the creases are sparse and deep, it indicates poor crease resistance. In general, this can be observed with the naked eye or detected using a digital optical microscope (Keyence-VHX, 20x). Specifically, in this invention, the maximum crease width is characterized in the optical microscope image; a maximum crease width less than or equal to 300 μm is considered excellent, a maximum crease width greater than 300 μm and less than or equal to 450 μm is considered average, and a maximum crease width greater than 450 μm is considered poor.

[0149] For example, Figure 1 , Figure 2 and Figure 3 The images are optical microscope images of mirror polyurethane synthetic leather samples from Examples 1, 4, and 10 after folding. The maximum scar width in Example 1 is 250 μm, in Example 4 it is 400 μm, and in Example 10 it is 600 μm.

[0150] 6. Fogging situation Take a sample of mirror-finished polyurethane synthetic leather and place it in a constant temperature and humidity chamber at 70℃ and 95% humidity for 3 months. After taking it out, observe the surface of the mirror layer with your eyes to see if there is white frost (if there is precipitation and fogging, there will be obvious white frost); no white frost is recorded as excellent, and white frost is recorded as poor.

[0151] Table 4 Test results of different embodiments and comparative examples

[0152] The test results above show that the wet-process polyurethane resin composition of the present invention, by compounding component A and component B in a certain ratio, can produce mirror-finish polyurethane synthetic leather with hydrolysis resistance, good washability, fine creases, low risk of precipitation fogging, and good peel strength without the use of silicone oil or other types of water-accelerating agents.

[0153] Specifically, the test results of Example 3 and Comparative Example 1 show that when the amount of chain extender and diisocyanate in component A is too low, the 100% modulus of component A is too low, resulting in reduced smoothness and peel strength of the corresponding mirror-finish wet-process base layer after washing; the mirror-finish polyurethane synthetic leather exhibits poor crease resistance and noticeable fogging. The test results of Example 2 and Comparative Example 2 show that when the amount of chain extender and diisocyanate in component A is too high, the 100% modulus of component A is too high, resulting in larger pores in the corresponding mirror-finish wet-process base layer, reduced smoothness and peel strength after washing; and poorer crease resistance of the mirror-finish polyurethane synthetic leather.

[0154] The test results of Example 3 and Comparative Example 3 show that when the amount of chain extender and diisocyanate in component B is too low, the 100% modulus of component B is too low, resulting in significantly worse smoothness and reduced peel strength in the corresponding mirror-finish wet-process base layer after washing; the crease resistance of the mirror-finish polyurethane synthetic leather is reduced, and the fogging is more obvious. The test results of Example 2 and Comparative Example 4 show that when the amount of chain extender and diisocyanate in component B is too high, the 100% modulus of component B is too high, resulting in significantly larger pores in the corresponding mirror-finish wet-process base layer, reduced smoothness after washing; and worsened crease resistance of the mirror-finish polyurethane synthetic leather.

[0155] Comparing the test results of Examples 1, 4-5 and Comparative Example 5, and the test results of Examples 1, 6-7 and Comparative Example 6, the appropriate introduction of polyester diol into component A and / or component B is beneficial to improving the resin's DMF removal ability and avoiding excessively large cells; when polyester diol is not present, the cell size increases and the crease resistance weakens; when the content of polyester diol is too high, the hydrolysis resistance of the material deteriorates.

[0156] The test results of Example 1 and Comparative Example 7 show that Example 1 introduces an appropriate amount of cell regulator based on Comparative Example 7, which can regulate the interaction between component A and component B, further improve coagulation uniformity and peel strength. Without using silicone oil or other types of water-washing agents, a mirror polyurethane synthetic leather with hydrolysis resistance, good water washing performance, fine creases, low risk of precipitation fogging, and good peel strength can be obtained.

[0157] The test results of Examples 1, 12-13 and Comparative Examples 8-9 show that in Comparative Example 8, the amount of component B was too large, the cell size was too large, and the hydrolysis resistance of the resin layer was poor. In Comparative Example 9, when the content of component B was too small, the improvement of the DMF removal ability was insufficient, which easily led to the resin layer becoming foggy and uneven.

[0158] The test results of Examples 1 and 8-11 show that polypropylene glycol has weak crystallinity and weak solidification kinetics. In component A and / or component B, controlling the proportion of polypropylene glycol in polyether diol within a certain range helps to stabilize the cell structure. When the proportion of polypropylene glycol in polyether diol is too low, the cell structure becomes significantly larger, and the crease resistance and peel strength deteriorate.

[0159] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wet-process polyurethane resin composition, characterized in that, Includes main ingredients and cell conditioner; The main material comprises component A (60%–95%) and component B (5%–40%) by mass percentage; the cell regulator is an alkane with a boiling point of 80–140°C. The raw materials for component A include the following components in parts by weight: 320-400 parts of polyether diol; 0-80 parts of polyester diol; Chain extender 20-35 parts; Antioxidant 0.5 to 1 part; Inorganic acid 0-0.02 parts; Catalyst 0.02–0.04 parts; 100-180 parts of diisocyanate; Solvent: 950–1900 parts; 0-2 parts of capping agent; The raw materials for component B include the following components in parts by weight: 240-300 parts of polyether diol; 0-60 parts of polyester diol; Chain extender 40-70 parts; Antioxidant 0-2 parts; Inorganic acid 0-0.05 parts; Catalyst 0-0.08 parts; 200-260 parts of diisocyanate; Solvent: 1250–1600 parts; 0-2 parts of capping agent.

2. The wet-process polyurethane resin composition according to claim 1, characterized in that, The 100% modulus of component A is 3.0–4.0 MPa; the 100% modulus of component B is 8.0–10.0 MPa.

3. The wet-process polyurethane resin composition according to claim 1, characterized in that, In component A, the amount of the polyester diol accounts for 5% to 15% of the total mass of the polyester diol and the polyether diol; In component B, the amount of the polyester diol accounts for 5% to 15% of the total mass of the polyester diol and the polyether diol; Preferably, the number-average molecular weights of the polyester diols in component A and component B are each independently 1000 to 3000; Preferably, the polyester diols in component A and component B are each independently selected from at least one of sebacic acid polyester diol and sebacic acid polyester diol; Preferably, the polyether diols in component A and component B are each independently selected from at least one of polytetrahydrofuran diol, polypropylene glycol, and ethylene glycol. Preferably, the number-average molecular weights of the polyether diols in component A and component B are each independently 1000 to 4000; Preferably, in component A, the polyoxypropylene glycol accounts for 70% to 100% of the total mass of the polyether diol, more preferably 80% to 100%. Preferably, in component B, the polyoxypropylene glycol accounts for 60% to 100% of the total mass of the polyether diol, more preferably 80% to 100%.

4. The wet-process polyurethane resin composition according to claim 1, characterized in that, The diisocyanates in component A and component B are each independently selected from at least one of toluene diisocyanate, diphenylmethane diisocyanate, and carbodiimide-modified diisocyanate; Preferably, the chain extenders in component A and component B are each independently selected from at least one of ethylene glycol, 1,4-butanediol, and diethylene glycol; Preferably, the solvent in component A and component B is N,N-dimethylformamide; Preferably, the capping agents in component A and component B are each independently selected from at least one of methanol, ethanol and isopropanol.

5. The wet-process polyurethane resin composition according to claim 1, characterized in that, The pore-conditioning agent includes at least one of n-heptane and n-octane; Preferably, the amount of the foam regulator is 0.5% to 3% of the mass of the main material.

6. The method for preparing the wet-process polyurethane resin composition according to any one of claims 1 to 5, characterized in that, The process includes the following steps: mixing and stirring component A, component B, and the bubble conditioner at 70–80°C; The preparation of component A includes: (a1) A polyether diol, a portion of an optional polyester diol, an optional inorganic acid, an antioxidant, and a portion of a solvent are mixed together, and a portion of a diisocyanate is added and mixed to carry out a polymerization reaction; (a2) Mix the materials from the polymerization reaction in step (a1), the chain extender, and part of the solvent, and carry out the polymerization reaction; (a3) Add some diisocyanate to the material after the polymerization reaction in step (a2) and carry out the polymerization reaction; (a4) The material after the polymerization reaction in step (a3), the remaining optional polyester diol, the remaining diisocyanate, the catalyst and the remaining solvent are mixed and subjected to polymerization reaction. When the viscosity of the system reaches the standard, an end-capping agent is optionally added for end-capping to obtain component A. The preparation of component B includes: (b1) A polyether diol, a portion of a chain extender, an optional inorganic acid, an optional antioxidant, and a portion of a solvent are mixed together, and a portion of a diisocyanate is added and mixed to carry out a polymerization reaction; (b2) The material after the polymerization reaction in step (b1), optional polyester diol, remaining chain extender and part of solvent are mixed and subjected to polymerization reaction; (b3) The material after polymerization reaction in step (b2), the remaining diisocyanate, the optional catalyst and the remaining solvent are mixed and subjected to polymerization reaction. When the viscosity of the system reaches the target, an end-capping agent is optionally added to end-cap the system to obtain component B.

7. The preparation method according to claim 6, characterized in that, It has at least one of the following characteristics: (1) In step (a1), the addition of a portion of diisocyanate to mix the system makes the isocyanate index 1.8 to 2.2; (2) In step (a3), the addition of a portion of diisocyanate makes the isocyanate index in the system 0.90 to 0.95; (3) In step (b1), the addition of a portion of diisocyanate to mix the system makes the isocyanate index 1.5 to 1.7; (4) In step (b1), the amount of chain extender used is 18% to 22% of the total amount of chain extender; (5) In step (a1), the temperature of the polymerization reaction is 70-80°C and the time of the polymerization reaction is 1-2 hours; (6) In step (a2), the temperature of the polymerization reaction is 70-80°C and the time of the polymerization reaction is 0.4-0.6 h; (7) In step (a3), the temperature of the polymerization reaction is 70-80°C and the time of the polymerization reaction is 1-2 hours; (8) In step (a4), the temperature of the polymerization reaction is 70-80°C; (9) In step (a4), the viscosity of the system after the polymerization reaction is 240-300 Pa·s / 25℃, and the solid content is 25%-35%; (10) In step (b1), the temperature of the polymerization reaction is 70-80°C and the time of the polymerization reaction is 1-2 hours; (11) In step (b2), the temperature of the polymerization reaction is 70-80°C and the time of the polymerization reaction is 0.4-0.6 h; (12) In step (b3), the temperature of the polymerization reaction is 70-80°C; (13) In step (b3), the viscosity of the system after the polymerization reaction is 100 to 160 Pa·s / 25℃ and the solid content is 25% to 35%.

8. A mirror-finish wet-laid bass, characterized in that, It includes a base fabric and a wet-process resin layer; the wet-process resin layer is mainly made of wet-process slurry; The wet slurry comprises the following components by weight: 100 parts of the wet-process polyurethane resin composition according to any one of claims 1 to 5; 50-70 parts of filler; 0-2 parts of color paste; Solvent 60-80 parts.

9. The method for preparing a mirror-finish wet-process bass as described in claim 8, characterized in that, The process includes the following steps: applying a wet slurry to the surface of a pretreated base fabric, then coagulating it in a coagulation bath, followed by washing and drying to obtain the mirror-finish wet base fabric. Preferably, the coagulation bath is a DMF aqueous solution with a sugar content of 14% to 18%.

10. A mirror-finish polyurethane synthetic leather, characterized in that, It consists of, in sequence, a mirror wet-laid base layer, an adhesive layer, and a mirror layer; The mirror wet base layer is made from the mirror wet base layer as described in claim 8.

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