A polyurethane resin, a polyurethane synthetic leather, and a preparation method and application thereof

Abstract

The application belongs to the technical field of polyurethane resin, and provides a polyurethane resin, a polyurethane synthetic leather and a preparation method and application thereof, raw materials for preparing the polyurethane resin include the following components: 9-23% of first bio-based polyol, 3-18% of polyurethane intermediate, 0.005-0.02% of first antioxidant, 0.001-0.003% of first catalyst, 3-6% of first isocyanate, 0.5-2% of first chain extender, 0.01-0.05% of first terminating agent, 0.01-0.05% of first anti-viscosity aid, 0.7-2.2% of astringency aid, 0.5-3% of polyether aid and 50-70% of first solvent, and the first bio-based polyol includes bio-based polytrimethylene ether glycol and bio-based polycarbonate glycol. The raw materials in the application are all derived from bio-based, the polyurethane synthetic leather is soft, has good astringency, excellent strength and hydrolysis resistance.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane resin technology, and particularly relates to a polyurethane resin, polyurethane synthetic leather, its preparation method and application. Background Technology

[0002] While natural leather, as a traditional material for ball manufacturing, possesses unique texture and performance, its inherent defects limit its widespread application in modern industrial production. Firstly, natural leather is expensive and its supply is limited, making it difficult to promote to a broad consumer base. Secondly, the material itself has poor resistance to mold and mildew, easily deforming, molding, and deteriorating in humid environments, severely impacting product lifespan. Furthermore, due to individual animal variations, the physical properties of natural leather (such as thickness, density, and tensile strength) are difficult to maintain uniformity, resulting in inconsistent final product quality that fails to meet the requirements of standardized competition balls.

[0003] To overcome the aforementioned shortcomings, artificial leather technology, especially polyurethane synthetic leather technology, has been rapidly developed and widely applied. Polyurethane artificial leather, due to its significant advantages such as controllable production costs, strong performance designability, and uniform quality, has become the mainstream material in the manufacture of balls (such as volleyballs, handballs, soccer balls, and basketballs).

[0004] CN114645470A discloses an environmentally friendly volleyball leather and its preparation method. The volleyball leather includes a base fabric layer, a solvent-free foam layer, and a wear-resistant surface layer, which are sequentially bonded and adhered along the thickness direction. The solvent-free polyurethane foam is a cured product of solvent-free polyurethane foam. The wear-resistant surface layer is a cured product of an oil-based fabric, which includes the following components by weight: 90-110 parts of matrix resin, 80-100 parts of solvent, 0.3-0.7 parts of leveling agent, 5-12 parts of color paste, and 20-40 parts of anti-wear agent. The color paste is an epoxy resin color paste, and the anti-wear agent is an inorganic powder with organic segments grafted onto its surface, the organic segments containing isocyanate groups. This invention forms a cross-linked structure between the anti-wear agent particles and the epoxy resin in the wear-resistant surface layer, reducing the possibility of color fading in the volleyball and improving the wear resistance of the surface layer, thus helping to extend the service life of the volleyball.

[0005] CN112933559A discloses a dry manufacturing process for PU-coated volleyballs, which includes the following components: modified PU leather, novel EVA, and inner bladder; the modified PU leather is composed of polyurethane resin, nylon-66 salt, curing agent, filler, and solvent. In the dry manufacturing process of this PU-coated volleyball, a multi-layer film prepared by the dry manufacturing process of polyurethane resin and nylon-66 salt is combined with a base fabric to manufacture modified PU leather, which has the characteristics of strong leather feel, good hand feel, softness and wear resistance, anti-drop, and easier ball grip and control. Adding filler to polyurethane resin can not only save production costs, but also improve the wear resistance of the finished product.

[0006] CN211215279U discloses a volleyball with a long service life, comprising a ball and a spherical structure. The spherical structure is adhered to the outer surface of the ball. The spherical structure includes an outer layer, an inner layer covered with a reinforcing fabric, an inner layer covered with a sandwich, an inner layer covered with a base fabric, and a skeleton covered with a frame. An elastic support rod is fixedly connected to the inner side of the skeleton, and a reinforcing inner bladder is fixedly installed on the inner side of the elastic support rod. The outer surface of the outer layer is coated with a polyurethane waterproof layer. The reinforcing fabric is made of polyamide fiber, the sandwich is made of leather, and the skeleton is made of butadiene rubber. This volleyball is not easily damaged or scratched, has a long service life, and can evenly absorb impact, preventing the ball from denting. Currently, research on synthetic leather for balls mainly focuses on abrasion resistance, feel, cost reduction, and service life, with less research on the hydrolysis resistance and grip of polyurethane synthetic leather used in balls.

[0007] Therefore, developing a soft polyurethane synthetic leather with good abrasiveness, excellent peel strength, and hydrolysis resistance is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a polyurethane resin, a polyurethane synthetic leather, a preparation method thereof, and its application. The raw materials for preparing the polyurethane resin and the polyurethane synthetic leather are both derived from bio-based sources, meeting EU export requirements. The resulting polyurethane synthetic leather is soft, has a good astringent feel, and possesses excellent peel strength and hydrolysis resistance.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a polyurethane resin, wherein the raw materials for preparing the polyurethane resin comprise the following components by mass fraction:

[0011] First bio-based polyols: 9%-23%;

[0012] Polyurethane intermediates: 3%-18%;

[0013] First antioxidant: 0.005%-0.02%;

[0014] The first catalyst is 0.001%-0.003%;

[0015] First isocyanate 3%-6%;

[0016] First chain extender: 0.5%-2%;

[0017] First terminator: 0.01%-0.05%;

[0018] First anti-tack and anti-blocking agent: 0.01%-0.05%;

[0019] Astringency enhancers: 0.7%-2.2%;

[0020] Polyether additives 0.5%-3%;

[0021] The first solvent is 50%-70%;

[0022] The first bio-based polyol includes a first bio-based polytrimethylene glycol and a first bio-based polycarbonate glycol.

[0023] The bio-based polyol used in this invention has good hydrolysis resistance. By adding astringency-enhancing agents, the astringency is improved without reducing hydrolysis resistance. The polyurethane intermediate not only adjusts the softness but also promotes washing during the preparation of polyurethane synthetic leather, preventing residual organic solvents from causing pitting on the polyurethane synthetic leather. This invention uses bio-based polyol, polyurethane intermediate, and other components in specific amounts to prepare polyurethane synthetic leather with good astringency, softness, excellent peel strength, and hydrolysis resistance.

[0024] The amount of the first bio-based polyol can be 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, or 23%, etc.

[0025] The amount of the polyurethane intermediate can be 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, or 18%, etc.

[0026] The amount of the first antioxidant can be 0.005%, 0.01%, 0.015%, or 0.02%, etc.

[0027] The amount of the first catalyst can be 0.001%, 0.002%, or 0.003%, etc.

[0028] The amount of the first isocyanate can be 3%, 4%, 5% or 6%, etc.

[0029] The amount of the first chain extender can be 0.5%, 1%, 1.5% or 2%, etc.

[0030] The amount of the first terminator can be 0.01%, 0.02%, 0.03%, 0.04%, or 0.05%, etc.

[0031] The amount of the first anti-tack and anti-blocking agent can be 0.01%, 0.02%, 0.03%, 0.04%, or 0.05%, etc.

[0032] The amount of the astringency aid can be 0.7%, 1%, 1.5%, 2% or 2.2%, etc.

[0033] The amount of the polyether additive can be 0.5%, 1%, 1.5%, 2%, 2.5%, or 3%, etc.

[0034] The amount of the first solvent can be 50%, 52%, 54%, 56%, 58%, 60%, 62%, 64%, 66%, 68%, or 70%, etc.

[0035] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0036] Preferably, the raw materials for preparing the polyurethane intermediate include the following components by mass fraction:

[0037] Second bio-based polyols: 8%-24%;

[0038] Second antioxidant 0.005%-0.02%;

[0039] The second catalyst is 0.001%-0.003%;

[0040] Second isocyanate 5%-8%;

[0041] Second chain extender: 0.5%-3%;

[0042] Second terminator: 0.03%-0.06%;

[0043] Second anti-tack and anti-blocking agent: 0.03%-0.06%;

[0044] The second solvent accounts for 70%-81%.

[0045] Preferably, the second bio-based polyol comprises a second bio-based polytrimethylene ether glycol and a second bio-based polycarbonate glycol.

[0046] In this invention, if too much polyurethane intermediate is used, although it can make the polyurethane synthetic leather softer, it will also reduce the peel strength. If too little polyurethane intermediate is used, it will be difficult to remove the organic solvent by washing during the preparation of polyurethane synthetic leather, resulting in a pitted surface on the polyurethane synthetic leather.

[0047] The amount of the second bio-based polyol can be 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, or 24%, etc.

[0048] The amount of the second antioxidant can be 0.005%, 0.01%, 0.015%, or 0.02%, etc.

[0049] The amount of the second catalyst can be 0.001%, 0.002%, or 0.003%, etc.

[0050] The amount of the second isocyanate can be 5%, 6%, 7% or 8%, etc.

[0051] The amount of the second chain extender can be 0.5%, 1%, 1.5%, 2%, 2.5% or 3%, etc.

[0052] The amount of the second terminator can be 0.03%, 0.04%, 0.05%, or 0.06%, etc.

[0053] The amount of the second anti-tack additive can be 0.03%, 0.04%, 0.05%, or 0.06%, etc.

[0054] The amount of the second solvent can be 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, or 81%, etc.

[0055] Preferably, based on the mass of the first bio-based polyol as 100%, the mass percentage of the first bio-based polycarbonate diol is 25%-55%, such as 25%, 27%, 29%, 31%, 33%, 35%, 37%, 39%, 41%, 43%, 45%, 47%, 49%, 51%, 53%, or 55%.

[0056] Preferably, based on the mass of the second bio-based polyol as 100%, the mass percentage of the second bio-based polycarbonate diol is 30%-70%, such as 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, 60%, 62%, 64%, 66%, 68%, or 70%.

[0057] Preferably, the weight-average molecular weight of the first bio-based polyol and the second bio-based polyol is independently 1500-3500, such as 1500, 1700, 1900, 2100, 2300, 2500, 2700, 2900, 3100, 3300 or 3500.

[0058] Preferably, the antioxidant comprises any one or a combination of at least two of the following: pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1076), 4,4'-thiobis(6-tert-butyl-3-methylphenol) (antioxidant 300), 1,2-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine (antioxidant 1024), N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide] (antioxidant 1098), or tris(2,4-di-tert-butylphenyl) phosphite (antioxidant B215).

[0059] Preferably, the first catalyst and the second catalyst comprise phosphoric acid.

[0060] Preferably, the first isocyanate and the second isocyanate each independently comprise toluene diisocyanate and / or 4,4'-diphenyl diisocyanate.

[0061] Preferably, the first chain extender and the second chain extender each independently comprise any one or a combination of at least two of ethylene glycol, 1,4-butanediol, or neopentyl glycol.

[0062] Preferably, the first terminator and the second terminator each independently comprise ethylene glycol.

[0063] Preferably, the first and second anti-tack additives comprise malic acid.

[0064] Preferably, the first solvent and the second solvent comprise N,N-dimethylformamide.

[0065] Preferably, the astringency aid comprises pentaerythritol rosin.

[0066] Conventional astringency additives are not resistant to hydrolysis. In this invention, pentaerythritol rosin is selected, which can improve the astringency of polyurethane synthetic leather without reducing its hydrolysis resistance.

[0067] Preferably, the polyether additive comprises a polyether polyol.

[0068] Preferably, the solid content of the polyurethane resin is 29wt%-31wt%, such as 29wt%, 29.5wt%, 30wt%, 30.5wt%, or 31wt%.

[0069] Preferably, the viscosity of the polyurethane resin at 25°C is 220,000-280,000 cps, such as 220,000 cps, 225,000 cps, 230,000 cps, 235,000 cps, 240,000 cps, 245,000 cps, 250,000 cps, 255,000 cps, 260,000 cps, 270,000 cps, 275,000 cps, or 280,000 cps.

[0070] Preferably, the method for preparing the polyurethane intermediate includes the following steps:

[0071] (1) Mix the second bio-based polyol, the second antioxidant, the second catalyst, a portion of the second isocyanate, and a portion of the second solvent, and react them;

[0072] (2) Add the remaining second solvent, the second chain extender, and the remaining second isocyanate, and react;

[0073] (3) Add a second terminator and a second anti-tack agent to obtain the polyurethane intermediate.

[0074] Preferably, in step (1), the molar ratio of the isocyanate group in the second isocyanate to the hydroxyl group in the second bio-based polyol is (0.35-0.9):1, for example, 0.35:1, 0.4:1, 0.45:1, 0.5:1, 0.55:1, 0.6:1, 0.65:1, 0.7:1, 0.75:1, 0.8:1, 0.85:1, or 0.9:1, etc. Within this range, the polyurethane resin can have suitable foaming properties, thereby achieving a balance between softness and peel strength in the polyurethane synthetic leather.

[0075] Preferably, the solid content of the polyurethane intermediate is 24wt%-26wt%, such as 24wt%, 24.5wt%, 25wt%, 25.5wt%, or 26wt%.

[0076] Preferably, the viscosity of the polyurethane intermediate at 25°C is 220,000-280,000 cps, such as 220,000 cps, 225,000 cps, 230,000 cps, 235,000 cps, 240,000 cps, 245,000 cps, 250,000 cps, 255,000 cps, 260,000 cps, 270,000 cps, 275,000 cps, or 280,000 cps.

[0077] Preferably, in step (1), the reaction temperature is 70-80℃, such as 70℃, 71℃, 72℃, 73℃, 74℃, 75℃, 76℃, 77℃, 78℃, 79℃ or 80℃.

[0078] Preferably, in step (1), the reaction time is 1-2 hours, for example, 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours or 2 hours.

[0079] In a second aspect, the present invention provides a method for preparing a polyurethane resin as described in the first aspect, the method comprising the following steps:

[0080] (1) Mix the first bio-based polyol, the first antioxidant, the first catalyst, a portion of the first isocyanate and a portion of the first solvent, and react them;

[0081] (2) Add part of the first solvent, the first chain extender and the remaining first isocyanate, and continue the reaction;

[0082] (3) Dilute with the remaining first solvent;

[0083] (4) Add the first terminator, the first anti-tack agent, the astringency agent and the polyether agent to obtain the polyurethane resin.

[0084] Preferably, in step (1), the reaction temperature is 70-80℃, such as 70℃, 71℃, 72℃, 73℃, 74℃, 75℃, 76℃, 77℃, 78℃, 79℃ or 80℃.

[0085] Preferably, in step (1), the viscosity of the mixture obtained by the reaction at 70°C is 20,000-40,000 cps, for example, 20,000 cps, 25,000 cps, 30,000 cps, 35,000 cps or 40,000 cps.

[0086] Thirdly, the present invention provides a polyurethane synthetic leather, wherein the polyurethane synthetic leather comprises the polyurethane resin described in the first aspect.

[0087] Preferably, the raw materials for preparing the polyurethane synthetic leather include the following components by weight:

[0088] 100 parts of polyurethane resin;

[0089] 1-3 parts calcium carbonate;

[0090] 40-50 parts of the third solvent;

[0091] 0.2-0.5 parts of color powder.

[0092] Preferably, the calcium carbonate comprises light calcium carbonate.

[0093] Preferably, the third solvent comprises N,N-dimethylformamide.

[0094] Preferably, the color powder includes brown powder.

[0095] The amount of calcium carbonate used can be 1 part, 2 parts, or 3 parts, etc.

[0096] The amount of the third solvent can be 40 parts, 42 parts, 44 parts, 46 parts, 48 ​​parts, or 50 parts, etc.

[0097] The amount of pigment used can be 0.2 parts, 0.3 parts, 0.4 parts, or 0.5 parts, etc.

[0098] Fourthly, the present invention provides a method for preparing polyurethane synthetic leather as described in the third aspect, the method comprising the following steps:

[0099] (1) Mix polyurethane resin, calcium carbonate, solvent and colorant to obtain a mixed solution;

[0100] (2) Immerse the substrate in mixed solvent A and heat it;

[0101] (3) The mixed solution is coated on the heated substrate surface, solidified, and dried to obtain the polyurethane synthetic leather.

[0102] Preferably, the substrate comprises needle-punched nonwoven fabric.

[0103] Preferably, the thickness of the substrate is 3-4 mm, such as 3 mm, 3.5 mm or 4 mm.

[0104] Preferably, the coating thickness is 2-3 mm, such as 2 mm, 2.5 mm or 3 mm.

[0105] Preferably, the coating process further includes a settling period.

[0106] Preferably, the settling time is 10-15 seconds, such as 10 seconds, 11 seconds, 12 seconds, 13 seconds, 14 seconds, or 15 seconds.

[0107] Preferably, the mixed solvent A comprises an aqueous solution of N,N-dimethylformamide with a mass fraction of 45%-55% (e.g., 45%, 47%, 49%, 51%, 53%, or 55%).

[0108] Preferably, the soaking time is 15-20 minutes, such as 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes, or 20 minutes.

[0109] Preferably, the heating temperature is 115-125℃, such as 115℃, 116℃, 117℃, 118℃, 119℃, 120℃, 121℃, 122℃, 123℃, 124℃ or 125℃.

[0110] Preferably, the heating time is 20-30 seconds, such as 20 seconds, 22 seconds, 24 seconds, 26 seconds, 28 seconds, or 30 seconds.

[0111] Preferably, after heating, the moisture content of the substrate is 35%-50%, such as 35%, 37%, 39%, 41%, 43%, 45%, 47%, 49%, or 50%.

[0112] Preferably, the solidification includes bringing one side of the substrate coated with the mixed solution close to the mixed solvent B.

[0113] Preferably, the mixed solvent B comprises an aqueous solution of N,N-dimethylformamide with a mass fraction of 15%-20% (e.g., 15%, 16%, 17%, 18%, 19% or 20%).

[0114] Preferably, the solidification time is 15-20 minutes, such as 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes, or 20 minutes.

[0115] Preferably, the solidification process further includes water washing.

[0116] Preferably, the drying temperature is 110-120℃, such as 110℃, 111℃, 112℃, 113℃, 114℃, 115℃, 116℃, 117℃, 118℃, 119℃ or 120℃.

[0117] Preferably, the drying time is 20-30 minutes, such as 20 minutes, 22 minutes, 24 minutes, 26 minutes, 28 minutes, or 30 minutes.

[0118] The preparation method specifically includes the following steps:

[0119] (1) Mix polyurethane resin, calcium carbonate, solvent and colorant, centrifuge to remove bubbles, and obtain a mixed solution;

[0120] (2) Immerse the substrate in a DMF aqueous solution with a mass fraction of 45%-55%, and heat the substrate at 115-125℃ for 20-30 seconds;

[0121] (3) The mixed solution is coated on the heated substrate surface, placed in a 15%-20% DMF aqueous solution, solidified for 15-20 min, washed with water to remove DMF using a squeezing roller, and dried at 110-120℃ for 20-30 min to obtain the polyurethane synthetic leather.

[0122] The polyurethane synthetic leather of this invention can be used for volleyball leather.

[0123] Compared with the prior art, the present invention has the following beneficial effects:

[0124] This invention uses bio-based polyols, polyurethane intermediates, and other components in specific amounts to prepare polyurethane synthetic leather with good astringency, a smoothness grade of 1, softness above 3.8, excellent peel strength (≥80N / 3cm), and hydrolysis resistance, making it suitable for volleyball leather. Detailed Implementation

[0125] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0126] The information sources for some raw materials in the preparation examples and embodiments of this invention are as follows:

[0127] Bio-based polycarbonate diol: TBE2000 from Anhui Huaihai Biotechnology Co., Ltd.

[0128] Bio-based polytrimethylene ether glycol: H2000 from Guangzhou Haoyi New Material Technology Co., Ltd.

[0129] Polyether additive A: Ningbo Guodu Chemical KP-3361R;

[0130] Polyether additive B: Ningbo Guodu Chemical KP-6000E;

[0131] Bio-based polytetrahydrofuran ether diol: BIO PTMEG 2000 from Guangzhou Haoyi New Material Technology Co., Ltd.

[0132] Brown powder: Jiangxi Sanyue New Materials Co., Ltd. PU8003;

[0133] Rosin pentaerythritol ester: Jiangxi Huajin New Materials Co., Ltd. 145 rosin resin;

[0134] Rosin resin: GH-D185 from Gaohe (Guangzhou) New Materials Co., Ltd.;

[0135] Light calcium carbonate: Xufeng Powder Co., Ltd. NC-60A.

[0136] Preparation Example 1

[0137] This preparation example provides a polyurethane intermediate and its preparation method. The raw materials for preparing the polyurethane intermediate include the following components by weight:

[0138] Bio-based polycarbonate diol: 50 parts;

[0139] Bio-based polytrimethylene ether glycol: 100 parts;

[0140] Antioxidant 1076: 0.1 parts;

[0141] Phosphoric acid: 0.02 parts;

[0142] MDI: 67.1 units;

[0143] Chain extender ethylene glycol: 12 parts;

[0144] Terminating agent ethylene glycol: 0.5 parts;

[0145] Malic acid: 0.5 parts;

[0146] DMF: 690.5 copies;

[0147] The preparation method of the polyurethane intermediate specifically includes the following steps:

[0148] (1) According to the above formula dosage, add bio-based polycarbonate diol, bio-based polytrimethylene ether diol, antioxidant 1076, phosphoric acid and 166 parts of DMF into the reaction flask, stir evenly, add 15.9 parts of MDI, and react at 70°C for 1 hour.

[0149] (2) Add 63 parts of DMF for dilution, add chain extender ethylene glycol, continue to stir evenly, and then add the remaining 51.2 parts of MDI to react and thicken;

[0150] (3) Add the remaining 461.5 parts of DMF for dilution, add ethylene glycol as a terminator to terminate the reaction, then add malic acid, continue stirring for 40 min, control the viscosity of the polyurethane intermediate at 25°C to be 250,000 cps and the solid content to be 25 wt%, cool, and obtain polyurethane intermediate A.

[0151] Preparation Example 2

[0152] This preparation example provides a polyurethane intermediate and its preparation method. The raw materials for preparing the polyurethane intermediate include the following components by weight:

[0153] Bio-based polycarbonate diol: 96.5 parts;

[0154] Bio-based polytrimethylene ether glycol: 50 parts;

[0155] Antioxidant 1010: 0.1 parts;

[0156] Phosphoric acid: 0.02 parts;

[0157] MDI: 65.5 servings;

[0158] Chain extender 1,4-butanediol: 17 parts;

[0159] Terminating agent ethylene glycol: 0.5 parts;

[0160] Malic acid: 0.5 parts;

[0161] DMF: 690.5 copies;

[0162] The preparation method of the polyurethane intermediate specifically includes the following steps:

[0163] (1) According to the above formula dosage, add bio-based polycarbonate diol, bio-based polytrimethylene ether diol, antioxidant 1010, phosphoric acid and 166 parts of DMF into the reaction flask, stir evenly, add 15.5 parts of MDI, and react at 70°C for 1 hour.

[0164] (2) Add 63 parts of DMF for dilution, add chain extender 1,4-butanediol, continue to stir evenly, and then add the remaining 50 parts of MDI to react and thicken;

[0165] (3) Add the remaining 461.5 parts of DMF for dilution, add ethylene glycol as a terminator to terminate the reaction, then add malic acid, continue stirring for 40 min, control the viscosity of the polyurethane intermediate at 25°C to be 250,000 cps and the solid content to be 25 wt%, cool, and obtain polyurethane intermediate B.

[0166] Preparation Example 3

[0167] This preparation example provides a polyurethane intermediate and its preparation method. The raw materials for preparing the polyurethane intermediate include the following components by weight:

[0168] Bio-based polycarbonate diol: 50 parts;

[0169] Bio-based polytrimethylene ether glycol: 100 parts;

[0170] Antioxidant 300: 0.1 parts;

[0171] Phosphoric acid: 0.02 parts;

[0172] MDI: 67.1 units;

[0173] Chain extender ethylene glycol: 12 parts;

[0174] Terminating agent ethylene glycol: 0.5 parts;

[0175] Malic acid: 0.5 parts;

[0176] DMF: 690.5 copies;

[0177] The preparation method of the polyurethane intermediate specifically includes the following steps:

[0178] (1) According to the above formula dosage, add bio-based polycarbonate diol, bio-based polytrimethylene ether diol, antioxidant 300, phosphoric acid and 166 parts of DMF into the reaction flask, stir evenly, add 7.5 parts of MDI, and react at 75°C for 1 hour;

[0179] (2) Add 63 parts of DMF for dilution, add chain extender ethylene glycol, continue stirring until uniform, and then add the remaining 59.6 parts of MDI to react and thicken;

[0180] (3) Add the remaining 461.5 parts of DMF for dilution, add ethylene glycol as a terminator to terminate the reaction, then add malic acid, continue stirring for 40 min, control the viscosity of the polyurethane intermediate at 25°C to be 250,000 cps and the solid content to be 25 wt%, cool, and obtain polyurethane intermediate C.

[0181] Preparation Example 4

[0182] This preparation example provides a polyurethane intermediate and its preparation method. The raw materials for preparing the polyurethane intermediate include the following components by weight:

[0183] Bio-based polycarbonate diol: 50 parts;

[0184] Bio-based polytrimethylene ether glycol: 97 parts;

[0185] Antioxidant 1076: 0.1 parts;

[0186] Phosphoric acid: 0.02 parts;

[0187] TDI: 61.98 units;

[0188] Chain extender neopentyl glycol: 20.15 parts;

[0189] Terminating agent ethylene glycol: 0.5 parts;

[0190] Malic acid: 0.5 parts;

[0191] DMF: 690.8 copies;

[0192] The preparation method of the polyurethane intermediate specifically includes the following steps:

[0193] (1) According to the above formula dosage, add bio-based polycarbonate diol, bio-based polytrimethylene ether diol, antioxidant 1076, phosphoric acid and 166 parts of DMF into the reaction flask, stir evenly, add 10.88 parts of TDI, and react at 80°C for 1 hour.

[0194] (2) Add 63 parts of DMF for dilution, add the chain extender neopentyl glycol, continue to stir evenly, and then add the remaining 51.1 parts of TDI to react and thicken;

[0195] (3) Add the remaining 461.8 parts of DMF for dilution, add ethylene glycol as a terminator to terminate the reaction, then add malic acid, continue stirring for 40 min, control the viscosity of the polyurethane intermediate at 25°C to be 250,000 cps and the solid content to be 25 wt%, cool, and obtain polyurethane intermediate D.

[0196] Preparation Example 5

[0197] The only difference from Preparation Example 1 is that the amount of bio-based polycarbonate diol is 20 parts and the amount of bio-based polytrimethylene ether diol is 130 parts. The amounts of the remaining components and the preparation method are the same as in Preparation Example 1, and polyurethane intermediate E is obtained.

[0198] Preparation Example 6

[0199] The only difference from Preparation Example 1 is that the amount of bio-based polycarbonate diol is 130 parts, the amount of bio-based polytrimethylene ether diol is 20 parts, and the amount of other components and the preparation method are the same as in Preparation Example 1, thus obtaining polyurethane intermediate F.

[0200] Preparation Example 7

[0201] The only difference from Preparation Example 1 is that 3.75 parts of MDI were added in step (1); the remaining 63.38 parts of MDI were added in step (2) to react and thicken; the amounts of the other components and the preparation methods were the same as in Preparation Example 1, and polyurethane intermediate G was obtained.

[0202] Example 1

[0203] This embodiment provides a polyurethane resin, polyurethane synthetic leather, and a method for preparing the same. The raw materials for preparing the polyurethane resin include the following components by weight:

[0204] Bio-based polycarbonate diol: 75 parts;

[0205] Bio-based polytrimethylene ether glycol: 75 parts;

[0206] Polyurethane intermediate A: 150.3 parts;

[0207] Antioxidant 1076: 0.1 parts;

[0208] Phosphoric acid: 0.02 parts;

[0209] MDI: 50.95 servings;

[0210] Chain extender ethylene glycol: 8 parts;

[0211] Terminating agent ethylene glycol: 0.3 parts;

[0212] Malic acid: 0.3 parts;

[0213] Rosin pentaerythritol ester: 9 parts;

[0214] Polyether additive A: 18 parts;

[0215] DMF: 526.07 copies;

[0216] The method for preparing the polyurethane resin includes the following steps:

[0217] (1) According to the above formula dosage, bio-based polycarbonate diol, bio-based polytrimethylene ether diol, antioxidant 1076, phosphoric acid and 168.87 parts of DMF were put into the reaction bottle, stirred evenly, and 18.75 parts of MDI were added. The reaction was carried out at 70°C to increase viscosity. The viscosity at 70°C was 20,000 cps.

[0218] (2) Add 40.2 parts DMF to dilute, then add chain extender ethylene glycol and 32.2 parts MDI, and continue the reaction;

[0219] (3) Add 317 parts DMF for dilution;

[0220] (4) Add ethylene glycol as a terminator to terminate the reaction. Add malic acid, polyurethane intermediate A, rosin pentaerythritol ester and polyether additive A. Control the viscosity of polyurethane resin at 25°C to 250,000 cps and the solid content to 30 wt%. Cool to obtain polyurethane resin A.

[0221] The raw materials for preparing the polyurethane synthetic leather include the following components by weight:

[0222] Polyurethane resin A: 100 parts;

[0223] Light calcium carbonate: 1 part;

[0224] DMF: 50 copies;

[0225] Brown powder: 0.3 parts;

[0226] The preparation method of the polyurethane synthetic leather specifically includes the following steps:

[0227] (1) According to the above formula dosage, mix polyurethane resin A, light calcium carbonate, DMF and brown powder evenly, centrifuge to remove bubbles, and obtain a mixed solution;

[0228] (2) Weigh the 3mm thick needle-punched nonwoven fabric, then soak it in 50% DMF aqueous solution for 20 minutes, then put it in a 120℃ oven for 25 seconds, weigh it, and keep the moisture content of the final needle-punched nonwoven fabric at 45%;

[0229] (3) Coat the surface of a 3mm thick needle-punched nonwoven fabric with a coating thickness of 2mm and let it stand for 10s; immerse the needle-punched nonwoven fabric coated with the mixed solution in a 15% DMF aqueous solution, with the coated side close to the solvent and the uncoated side on top of the solvent, and let it solidify for 15min; wash with water using a squeeze roller to remove DMF, and dry at 120℃ for 20min to obtain the polyurethane synthetic leather.

[0230] Example 2

[0231] This embodiment provides a polyurethane resin, polyurethane synthetic leather, and a method for preparing the same. The raw materials for preparing the polyurethane resin include the following components by weight:

[0232] Bio-based polycarbonate diol: 40 parts;

[0233] Bio-based polytrimethylene ether glycol: 110 parts;

[0234] Polyurethane intermediate B: 150.3 parts;

[0235] Antioxidant 1010: 0.1 parts;

[0236] Phosphoric acid: 0.02 parts;

[0237] TDI: 45.46 units;

[0238] Chain extender neopentyl glycol: 13.5 parts;

[0239] Terminating agent ethylene glycol: 0.3 parts;

[0240] Malic acid: 0.3 parts;

[0241] Rosin pentaerythritol ester: 9 parts;

[0242] Polyether additive A: 18 parts;

[0243] DMF: 526.07 copies;

[0244] The method for preparing the polyurethane resin includes the following steps:

[0245] (1) According to the above formula dosage, bio-based polycarbonate diol, bio-based polytrimethylene ether diol, antioxidant 1010, phosphoric acid and 168.87 parts of DMF were put into the reaction bottle, stirred evenly, and 13.06 parts of TDI were added. The reaction was carried out at 80°C to increase viscosity. The viscosity at 70°C was 30,000 cps.

[0246] (2) Add 40.2 parts DMF for dilution, then add the chain extender neopentyl glycol and 32.4 parts TDI, and continue the reaction;

[0247] (3) Add 317 parts DMF for dilution;

[0248] (4) Add ethylene glycol as a terminator to terminate the reaction. Add malic acid, polyurethane intermediate B, rosin pentaerythritol ester and polyether additive A. Control the viscosity of polyurethane resin at 25°C to 250,000 cps and the solid content to 30 wt%. Cool to obtain polyurethane resin B.

[0249] The raw materials for preparing the polyurethane synthetic leather include the following components by weight:

[0250] Polyurethane resin B: 100 parts;

[0251] Light calcium carbonate: 2 parts;

[0252] DMF: 45 copies;

[0253] Brown powder: 0.3 parts;

[0254] The preparation method of the polyurethane synthetic leather specifically includes the following steps:

[0255] (1) According to the above formula dosage, mix polyurethane resin B, light calcium carbonate, DMF and brown powder evenly, centrifuge to remove bubbles, and obtain a mixed solution;

[0256] (2) Weigh the 3mm thick needle-punched nonwoven fabric, then soak it in 50% DMF aqueous solution for 20min, then put it in a 120℃ oven for 20s, weigh it, and keep the moisture content of the final needle-punched nonwoven fabric at 43%;

[0257] (3) Coat the surface of a 3mm thick needle-punched nonwoven fabric with the mixed solution, and let it stand for 12s; put the needle-punched nonwoven fabric coated with the mixed solution into a 17% DMF aqueous solution, with the coated side close to the solvent and the uncoated side on the solvent, and let it solidify for 20min; wash with water using a squeeze roller to remove DMF, and dry at 110℃ for 30min to obtain the polyurethane synthetic leather.

[0258] Example 3

[0259] This embodiment provides a polyurethane resin, polyurethane synthetic leather, and a method for preparing the same. The raw materials for preparing the polyurethane resin include the following components by weight:

[0260] Bio-based polycarbonate diol: 45 parts;

[0261] Bio-based polytrimethylene ether glycol: 124 parts;

[0262] Polyurethane intermediate C: 150.3 parts;

[0263] Antioxidant 300: 0.1 parts;

[0264] Phosphoric acid: 0.02 parts;

[0265] TDI: 51.28 units;

[0266] Chain extender neopentyl glycol: 15.24 parts;

[0267] Terminating agent ethylene glycol: 0.3 parts;

[0268] Malic acid: 0.3 parts;

[0269] Rosin pentaerythritol ester: 9 parts;

[0270] Polyether additive B: 18 parts;

[0271] DMF: 606.6 copies;

[0272] The method for preparing the polyurethane resin includes the following steps:

[0273] (1) According to the above formula dosage, put bio-based polycarbonate diol, bio-based polytrimethylene ether diol, antioxidant 300, phosphoric acid and 184 parts of DMF into the reaction bottle, stir evenly, add 14.7 parts of TDI, react at 80°C to increase viscosity, and the viscosity at 70°C is 40,000 cps.

[0274] (2) Add 51.6 parts of DMF for dilution, then add the chain extender neopentyl glycol and 36.58 parts of TDI, and continue the reaction;

[0275] (3) Add 371 parts DMF for dilution;

[0276] (4) Add ethylene glycol as a terminator to terminate the reaction, add malic acid, polyurethane intermediate C, rosin pentaerythritol ester and polyether additive B, control the viscosity of polyurethane resin at 25°C to be 250,000 cps and the solid content to be 30 wt%, cool to obtain polyurethane resin C.

[0277] The raw materials for preparing the polyurethane synthetic leather include the following components by weight:

[0278] Polyurethane resin C: 100 parts;

[0279] Light calcium carbonate: 3 parts;

[0280] DMF: 40 copies;

[0281] 0.3 parts brown powder;

[0282] The preparation method of the polyurethane synthetic leather specifically includes the following steps:

[0283] (1) According to the above formula dosage, mix polyurethane resin C, light calcium carbonate, DMF and brown powder evenly, centrifuge to remove bubbles, and obtain a mixed solution;

[0284] (2) Weigh the 3mm thick needle-punched nonwoven fabric, then soak it in 45% DMF aqueous solution for 20 minutes, then put it in a 120℃ oven for 30 seconds, weigh it, and keep the moisture content of the final needle-punched nonwoven fabric at 40%;

[0285] (3) Coat the surface of a 3mm thick needle-punched nonwoven fabric with a coating thickness of 2mm and let it stand for 15s; immerse the needle-punched nonwoven fabric coated with the mixed solution in a 20% DMF aqueous solution, with the coated side close to the solvent and the uncoated side on top of the solvent, and let it solidify for 18min; wash with water using a squeeze roller to remove DMF, and dry at 115℃ for 25min to obtain the polyurethane synthetic leather.

[0286] Example 4

[0287] This embodiment provides a polyurethane resin, polyurethane synthetic leather, and a method for preparing the same. The raw materials for preparing the polyurethane resin include the following components by weight:

[0288] Bio-based polycarbonate diol: 75 parts;

[0289] Bio-based polytrimethylene ether glycol: 75 parts;

[0290] Polyurethane intermediate D: 150.3 parts;

[0291] Antioxidant 1098: 0.1 parts;

[0292] Phosphoric acid: 0.02 parts;

[0293] MDI: 50.95 servings;

[0294] Chain extender ethylene glycol: 8 parts;

[0295] Terminating agent ethylene glycol: 0.3 parts;

[0296] Malic acid: 0.3 parts;

[0297] Rosin pentaerythritol ester: 18 parts;

[0298] Polyether additive A: 9 parts;

[0299] DMF: 526.07 copies;

[0300] The method for preparing the polyurethane resin includes the following steps:

[0301] (1) According to the above formula dosage, bio-based polycarbonate diol, bio-based polytrimethylene ether diol, antioxidant 1098, phosphoric acid and 168.87 parts of DMF were put into the reaction bottle, stirred evenly, and 18.75 parts of MDI were added. The reaction was carried out at 70°C to increase viscosity. The viscosity at 70°C was 30,000 cps.

[0302] (2) Add 40.2 parts DMF to dilute, then add chain extender ethylene glycol and 32.2 parts MDI, and continue the reaction;

[0303] (3) Add 317 parts DMF for dilution;

[0304] (4) Add ethylene glycol as a terminator to terminate the reaction, add malic acid, polyurethane intermediate D, rosin pentaerythritol ester and polyether additive A, control the viscosity of polyurethane resin at 25°C to be 250,000 cps and the solid content to be 30 wt%, cool to obtain polyurethane resin D.

[0305] The raw materials for preparing the polyurethane synthetic leather include the following components by weight:

[0306] Polyurethane resin D: 100 parts;

[0307] Light calcium carbonate: 3 parts;

[0308] DMF: 50 copies;

[0309] Brown powder: 0.3 parts;

[0310] The preparation method of the polyurethane synthetic leather specifically includes the following steps:

[0311] (1) According to the above formula dosage, mix polyurethane resin D, light calcium carbonate, DMF and brown powder evenly, centrifuge to remove bubbles, and obtain a mixed solution;

[0312] (2) Weigh the 3mm thick needle-punched nonwoven fabric, then soak it in 55% DMF aqueous solution for 20 minutes, then put it in a 120℃ oven for 30 seconds, weigh it, and keep the moisture content of the final needle-punched nonwoven fabric at 40%;

[0313] (3) Coat the surface of a 3mm thick needle-punched nonwoven fabric with a coating thickness of 2mm and let it stand for 15s; immerse the needle-punched nonwoven fabric coated with the mixed solution in a 15% DMF aqueous solution, with the coated side close to the solvent and the uncoated side on top of the solvent, and let it solidify for 15min; wash with water using a squeeze roller to remove DMF, and dry at 120℃ for 20min to obtain the polyurethane synthetic leather.

[0314] Comparative Example 1

[0315] The only difference from Example 1 is that the polyurethane intermediate E obtained in Preparation Example 5 is used to prepare polyurethane resin, and then polyurethane synthetic leather is prepared. The other components and preparation methods are the same as in Example 1.

[0316] Comparative Example 2

[0317] The only difference from Example 1 is that the polyurethane intermediate F obtained in Preparation Example 6 is used to prepare polyurethane resin, and then polyurethane synthetic leather is prepared. The other components and preparation methods are the same as in Example 1.

[0318] Comparative Example 3

[0319] The only difference from Example 1 is that the polyurethane intermediate G obtained in Preparation Example 7 is used to prepare polyurethane resin, and then polyurethane synthetic leather is prepared. The other components and preparation methods are the same as in Example 1.

[0320] Comparative Example 4

[0321] The only difference from Example 1 is that in step (1) of the preparation method of the polyurethane resin, the reaction is carried out at 70°C to increase viscosity, and the viscosity at 70°C is 70,000 cps. The other components and preparation methods are the same as in Example 1.

[0322] Comparative Example 5

[0323] The only difference from Example 1 is that the pentaerythritol rosin is replaced with an equal mass of rosin resin, while the other components and preparation methods are the same as in Example 1.

[0324] Comparative Example 6

[0325] The only difference from Example 1 is that the raw materials for preparing the polyurethane resin do not contain polyurethane intermediates, while the other components and preparation methods are the same as in Example 1.

[0326] Comparative Example 7

[0327] The only difference from Example 1 is that the amount of polyurethane intermediate A is 300.6 parts (accounting for 58.3%), while the other components and preparation methods are the same as in Example 1.

[0328] Comparative Example 8

[0329] The only difference from Example 1 is that bio-based polytrimethylene ether glycol is replaced with an equimolar amount of bio-based polytetrahydrofuran ether glycol, while the other components and preparation methods are the same as in Example 1.

[0330] Performance testing

[0331] (1) Softness: Tested according to QB / T 5515-2017 standard. The higher the value, the softer the material.

[0332] (2) Smoothness rating: Tested according to QB / T 5352-2018 standard. The higher the smoothness rating, the worse the astringency effect.

[0333] (3) Peel strength: Tested in accordance with GB / T 38612-2020 standard.

[0334] (4) Hydrolysis resistance: The hydrolysis resistance of polyurethane synthetic leather was tested according to the standard QB / T 4671-2014, using the room temperature alkaline solution accelerated method.

[0335] Following the above testing methods, the performance of the polyurethane synthetic leather provided in the examples and comparative examples was tested, and the results are shown in Table 1:

[0336] Table 1

[0337]

[0338] As shown in Table 1, the polyurethane synthetic leather prepared by this invention has good astringency, with a smoothness grade of 1, softness of 3.8 or higher, excellent peel strength (≥80N / 3cm), and hydrolysis resistance (peel strength decreases by ≤4% after 24h alkali soaking).

[0339] As can be seen from the comparison between Example 1 and Comparative Examples 1-2, the amounts of the two bio-based polyols used in the preparation of polyurethane intermediates both exceeded the limits of the present invention. Therefore, the softness and peel strength of the polyurethane synthetic leather decreased.

[0340] As can be seen from the comparison between Example 1 and Comparative Example 3, in the preparation of polyurethane intermediates, the molar ratio of isocyanate group to hydroxyl group in step (1) is 0.2:1, which is lower than the (0.35-0.9) of the present invention, resulting in poor foaming properties of polyurethane resin and a decrease in softness and peel strength.

[0341] As can be seen from the comparison between Example 1 and Comparative Example 4, in the preparation process of polyurethane resin, the prepolymer viscosity in step (1) reaches 70,000 cps (70°C). The excessively high viscosity causes the polyurethane resin to solidify faster, and the surface of the polyurethane synthetic leather is damaged, making it impossible to conduct performance tests.

[0342] As can be seen from the comparison between Example 1 and Comparative Example 5, when rosin resin is used instead of pentaerythritol rosin in this invention, the hydrolysis resistance of polyurethane synthetic leather is significantly reduced due to the poor hydrolysis resistance of rosin resin.

[0343] As can be seen from the comparison between Example 1 and Comparative Example 6, the raw materials for preparing polyurethane resin in Comparative Example 6 do not contain polyurethane intermediates, which leads to a decrease in the softness of polyurethane synthetic leather. At the same time, during the water washing process in the preparation of polyurethane synthetic leather, DMF is not completely removed. After drying, the surface of polyurethane synthetic leather is corroded by the DMF that is not left behind, resulting in a pitted surface.

[0344] As can be seen from the comparison between Example 1 and Comparative Example 7, if too much polyurethane intermediate is added, although it can improve the softness of polyurethane synthetic leather, it will lead to a significant decrease in peel strength.

[0345] As can be seen from the comparison between Example 1 and Comparative Example 8, when bio-based polytrimethylene ether glycol is replaced with bio-based polytetrahydrofuran ether glycol, bio-based polytetrahydrofuran ether glycol has a more regular chemical structure than bio-based polytrimethylene ether glycol, resulting in higher crystallinity and thus higher peel strength, but the feel is significantly harder.

[0346] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A polyurethane resin, characterized in that, The raw materials for preparing the polyurethane resin include the following components by mass fraction: First bio-based polyols: 9%-23%; Polyurethane intermediates: 3%-18%; First antioxidant: 0.005%-0.02%; The first catalyst is 0.001%-0.003%; First isocyanate 3%-6%; First chain extender: 0.5%-2%; First terminator: 0.01%-0.05%; First anti-tack and anti-blocking agent: 0.01%-0.05%; Astringency enhancers: 0.7%-2.2%; Polyether additives 0.5%-3%; The first solvent is 50%-70%; The first bio-based polyol includes a first bio-based polytrimethylene ether glycol and a first bio-based polycarbonate glycol; The raw materials for preparing the polyurethane intermediate include the following components by mass fraction: Second bio-based polyols: 8%-24%; Second antioxidant 0.005%-0.02%; The second catalyst is 0.001%-0.003%; Second isocyanate 5%-8%; Second chain extender: 0.5%-3%; Second terminator: 0.03%-0.06%; Second anti-tack and anti-blocking agent: 0.03%-0.06%; The second solvent accounts for 70%-81%; The second bio-based polyol comprises a second bio-based polytrimethylene ether glycol and a second bio-based polycarbonate glycol; based on the mass of the second bio-based polyol being 100%, the mass percentage of the second bio-based polycarbonate glycol is 30%-70%; The astringency enhancer includes pentaerythritol rosin; The method for preparing the polyurethane intermediate includes the following steps: (1) Mix the second bio-based polyol, the second antioxidant, the second catalyst, part of the second isocyanate and part of the second solvent, and react; the molar ratio of isocyanate groups in the second isocyanate to hydroxyl groups in the second bio-based polyol is (0.35-0.9):1; The method for preparing the polyurethane resin includes the following steps: (1) Mix the first bio-based polyol, the first antioxidant, the first catalyst, part of the first isocyanate and part of the first solvent and react them; the resulting mixture has a viscosity of 20,000-40,000 cps at 70°C.

2. The polyurethane resin according to claim 1, characterized in that, Based on the mass of the first bio-based polyol being 100%, the mass percentage of the first bio-based polycarbonate diol is 25%-55%; And / or, the weight-average molecular weight of the first bio-based polyol and the second bio-based polyol are each independently 1500-3500; And / or, the first antioxidant and the second antioxidant each independently comprise any one or a combination of at least two of the following: pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 4,4'-thiobis(6-tert-butyl-3-methylphenol), 1,2-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine, N,N'-(hexane-1,6-diyl)bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide] or tris(2,4-di-tert-butylphenyl) phosphite; And / or, the first catalyst and the second catalyst comprise phosphoric acid; And / or, the first isocyanate and the second isocyanate each independently comprise toluene diisocyanate and / or 4,4'-diphenyl diisocyanate; And / or, the first chain extender and the second chain extender each independently comprise any one or a combination of at least two of ethylene glycol, 1,4-butanediol or neopentyl glycol; And / or, the first terminator and the second terminator each independently comprise ethylene glycol; And / or, the first anti-tack and the second anti-tack additive include malic acid; And / or, the first solvent and the second solvent comprise N,N-dimethylformamide.

3. The polyurethane resin according to claim 1, characterized in that, The polyether additives include polyether polyols; And / or, the solid content of the polyurethane resin is 29wt%-31wt%; And / or, the viscosity of the polyurethane resin at 25°C is 220,000-280,000 cps; And / or, the method for preparing the polyurethane intermediate includes the following steps: (1) Mix the second bio-based polyol, the second antioxidant, the second catalyst, a portion of the second isocyanate, and a portion of the second solvent, and react them; (2) Add the remaining second solvent, the second chain extender, and the remaining second isocyanate, and react; (3) Add a second terminator and a second anti-tack agent to obtain the polyurethane intermediate; And / or, the solid content of the polyurethane intermediate is 24wt%-26wt%; And / or, the viscosity of the polyurethane intermediate at 25°C is 220,000-280,000 cps; And / or, in step (1), the reaction temperature is 70-80°C; And / or, in step (1), the reaction time is 1-2 hours.

4. The method for preparing polyurethane resin according to any one of claims 1-3, characterized in that, The preparation method includes the following steps: (1) Mix the first bio-based polyol, the first antioxidant, the first catalyst, a portion of the first isocyanate and a portion of the first solvent, and react them; (2) Add part of the first solvent, the first chain extender and the remaining first isocyanate, and continue the reaction; (3) Dilute with the remaining first solvent; (4) Add the first terminator, the first anti-tack and anti-tack agent, the astringency agent, the pentaerythritol rosin and the polyether agent to obtain the polyurethane resin.

5. The preparation method according to claim 4, characterized in that, In step (1), the reaction temperature is 70-80℃; And / or, in step (1), the viscosity of the mixture obtained from the reaction is 20,000-40,000 cps at 70°C.

6. A polyurethane synthetic leather, characterized in that, The polyurethane synthetic leather comprises the polyurethane resin according to any one of claims 1-3.

7. The polyurethane synthetic leather according to claim 6, characterized in that, The raw materials for preparing the polyurethane synthetic leather include the following components by weight: 100 parts of polyurethane resin; 1-3 parts calcium carbonate; 40-50 parts of the third solvent; Color powder 0.2-0.5 parts; And / or, the calcium carbonate includes light calcium carbonate; And / or, the third solvent includes N,N-dimethylformamide; And / or, the pigment includes brown pigment.

8. A method for preparing polyurethane synthetic leather as described in claim 6 or 7, characterized in that, The preparation method includes the following steps: (1) Mix polyurethane resin, calcium carbonate, solvent and colorant to obtain a mixed solution; (2) Immerse the substrate in mixed solvent A and heat it; (3) The mixed solution is coated on the heated substrate surface, solidified, and dried to obtain the polyurethane synthetic leather.

9. The preparation method according to claim 8, characterized in that, The substrate includes needle-punched nonwoven fabric; And / or, the thickness of the substrate is 3-4 mm; And / or, the coating thickness is 2-3 mm; And / or, the coating process further includes a settling period; And / or, the settling time is 10-15 seconds; And / or, the mixed solvent A comprises an aqueous solution of N,N-dimethylformamide with a mass fraction of 45%-55%; And / or, the soaking time is 15-20 minutes; And / or, the heating temperature is 115-125°C; And / or, the heating time is 20-30 seconds; And / or, after heating, the moisture content of the substrate is 35%-50%; And / or, the solidification includes bringing one side of the substrate coated with the mixed solution close to the mixed solvent B; And / or, the mixed solvent B comprises an aqueous solution of N,N-dimethylformamide with a mass fraction of 15%-20%; And / or, the solidification time is 15-20 min; And / or, the solidification process further includes water washing; And / or, the drying temperature is 110-120°C; And / or, the drying time is 20-30 minutes.

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