Polyurethane resin, synthetic leather and preparation method and application thereof

Abstract

The present application relates to a kind of polyurethane resin, synthetic leather and its preparation method and application, it is related to polyurethane technical field, the preparation raw material of the polyurethane resin includes bio-based polyester polyol, polyolefin polyol, isocyanate, chain extender, pore forming agent and solvent;The preparation raw material of the bio-based polyester polyol includes bio-based dihydric alcohol, bio-based diacid and small molecule branched dihydric alcohol.The polyurethane resin provided in the present application has high bio-based content, by introducing small molecule branched dihydric alcohol into bio-based polyester polyol, branched structure provides scratch resistance for synthetic leather with polyurethane resin as coating layer, the crystallinity of polyurethane resin is reduced by compounding polyolefin polyol, to give the soft hand feeling of the above-mentioned synthetic leather, the addition of chain extender and pore forming agent makes polyurethane have excellent foaming property, to give the excellent water absorption of the above-mentioned synthetic leather and further improve its hand feeling.

Description

Technical Field

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

[0002] Synthetic leather made from polyurethane resin has excellent properties such as simulation, breathability, and softness, making it one of the most ideal alternatives to natural leather. It is widely used in clothing, home furnishings, sporting goods, electronic devices, and other fields.

[0003] Currently, most synthetic leather used for grips focuses on improving its grip (anti-slip properties), wrinkle resistance, and water absorption. However, as market demands continue to rise, the performance requirements for grip leather are also gradually increasing, especially requiring grip leather to have scratch resistance, softness, and water absorption, and preferably be made of environmentally friendly materials.

[0004] CN108485242A discloses a polyurethane synthetic leather with a wrinkled feel, its preparation method and application. Although the synthetic leather has the advantages of being soft, having a strong surface roughness and a certain water absorption capacity, its water absorption speed and water absorption effect are poor, and no attention has been paid to how to improve the scratch resistance of the synthetic leather.

[0005] CN104480731A discloses a breathable polyurethane synthetic leather that utilizes hydrogel technology to give the synthetic leather superior water absorption. However, the addition of water-absorbing materials such as lignocellulose, while giving the synthetic leather excellent water absorption, affects its overall scratch resistance. Furthermore, soft, highly absorbent polyurethane materials cannot simultaneously possess scratch resistance.

[0006] Therefore, how to provide an environmentally friendly synthetic leather that combines softness, scratch resistance, and water absorption has become an urgent problem to be solved. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a polyurethane resin, synthetic leather, and a method for preparing the same. By designing the raw materials and formulations for preparing bio-based polyester polyol and polyurethane resin, the synthetic leather using the polyurethane resin provided by this invention as a coating layer possesses both a soft feel and excellent scratch resistance and water absorption.

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

[0009] In a first aspect, the present invention provides a polyurethane resin, wherein the raw materials for preparing the polyurethane resin include bio-based polyester polyol, polyolefin polyol, isocyanate, chain extender, pore-forming agent and solvent.

[0010] The raw materials for preparing the bio-based polyester polyol include bio-based diols, bio-based dicarboxylic acids, and small-molecule branched diols.

[0011] This invention reduces the crystallinity of bio-based polyester polyols by introducing small-molecule branched diols into them. The branched structure provides hardness to the polyurethane resin, giving the synthetic leather with polyurethane resin as the coating layer excellent scratch resistance. The resulting bio-based polyester polyol compounded with polyolefin polyols further reduces the crystallinity of the polyurethane resin, giving the synthetic leather with polyurethane resin as the coating layer a soft feel. The addition of chain extenders and pore-forming agents gives the polyurethane excellent foaming properties, resulting in excellent water absorption and further improving the feel of the synthetic leather.

[0012] Preferably, the raw materials for preparing the bio-based polyester polyol include the following components by mass percentage:

[0013] Bio-based diols 32-52%;

[0014] Bio-based dicarboxylic acids 47-66%;

[0015] Small molecules containing 0.5-3% branched diols.

[0016] Among them, 32-52% can be, for example, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50%, or 52%; 47-66% can be, for example, 47%, 49%, 50%, 52%, 54%, 56%, 58%, 60%, 62%, 64%, or 66%; 0.5-3% can be, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, or 3%.

[0017] Preferably, the molar ratio of the bio-based diol to the small-molecule branched diol is (26-33):1, for example, it can be 26:1, 27:1, 28:1, 29:1, 30:1, 31:1, 32:1, or 33:1. If too much small-molecule branched diol is added, the resulting synthetic leather will be too soft and have poor scratch resistance; if too little is added, the resulting synthetic leather will feel too hard.

[0018] Preferably, the bio-based diol includes bio-based 1,5-pentanediol and / or bio-based 1,3-butanediol.

[0019] Preferably, the bio-based dicarboxylic acid includes bio-based 1,4-succinic acid and / or bio-based sebacic acid.

[0020] Preferably, the small molecule branched diol includes 2-butyl-2-ethyl-1,3-propanediol and / or 2,4-diethyl-1,5-pentanediol.

[0021] Preferably, based on the total mass of the raw materials for preparing bio-based polyester polyols as 100%, the raw materials for preparing bio-based polyester polyols also include 0.005-0.01% catalyst, for example, it can be 0.005%, 0.006%, 0.007%, 0.008%, 0.009% or 0.01%, etc.

[0022] Preferably, the catalyst comprises any one or a combination of at least two of p-toluenesulfonic acid, stannous octanoate, or bismuth carboxylate.

[0023] Preferably, the bio-based polyester polyol is prepared by the following method, which includes the following steps:

[0024] (S1) A mixture of bio-based diols, bio-based dicarboxylic acids, and small-molecule branched diols is reacted.

[0025] (S2) Vacuum treatment is performed on the reaction system obtained in step (1);

[0026] (S3) Add a catalyst to the reaction system obtained in step (2) and continue the reaction to obtain the bio-based polyester polyol.

[0027] Preferably, the reaction temperature in step (S1) is 135-235℃, for example, it can be 135℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃, 230℃ or 235℃, etc., and the reaction time is 7-10h, for example, it can be 7h, 8h, 9h or 10h, etc.

[0028] Preferably, step (S1) is performed under an inert gas flow.

[0029] Preferably, the inert gas includes nitrogen.

[0030] Preferably, the flow rate of the inert gas is 0.3-0.6 L / min, for example, it can be 0.3 L / min, 0.4 L / min, 0.5 L / min or 0.6 L / min, etc.

[0031] Preferably, the vacuum degree of the vacuum treatment in step (S2) is -0.05 to -0.08 MPa, for example, it can be -0.05 MPa, -0.06 MPa, -0.07 MPa or -0.08 MPa, and the vacuum treatment time is 8-13 h, for example, it can be 8 h, 9 h, 10 h, 11 h, 12 h or 13 h.

[0032] Preferably, the acid value of the reaction system after vacuum treatment in step (S2) is 25-35 mgKOH / g, for example, it can be 25 mgKOH / g, 26 mgKOH / g, 28 mgKOH / g, 30 mgKOH / g, 32 mgKOH / g, 34 mgKOH / g or 35 mgKOH / g, etc.

[0033] Preferably, the reaction in step (S3) is carried out under vacuum, with a vacuum degree of -0.06 to -0.10 MPa, such as -0.06 MPa, -0.07 MPa, -0.08 MPa, -0.09 MPa, or -0.10 MPa.

[0034] Preferably, the reaction temperature in step (S3) is 230-235°C, for example, it can be 230°C, 231°C, 232°C, 233°C, 234°C or 235°C.

[0035] Preferably, in step (S3), the acid value of the reaction system is 0.2-0.8 mgKOH / g, for example, 0.2 mgKOH / g, 0.3 mgKOH / g, 0.4 mgKOH / g, 0.5 mgKOH / g, 0.6 mgKOH / g, 0.7 mgKOH / g, or 0.8 mgKOH / g, and the hydroxyl value is 35-39 mgKOH / g, for example, 35 mgKOH / g, 36 mgKOH / g, 37 mgKOH / g, 38 mgKOH / g, or 39 mgKOH / g.

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

[0037] Bio-based polyester polyols 11-15%;

[0038] Polyolefin polyols 1-6%;

[0039] Isocyanates 4-10%;

[0040] 1-4% pore-forming agent;

[0041] Chain extender 1-4%;

[0042] Solvent content: 65-80%.

[0043] Among them, 11-15% can be, for example, 11%, 12%, 13%, 14%, or 15%; 1-6% can be, for example, 1%, 2%, 3%, 4%, 5%, or 6%; 4-10% can be, for example, 4%, 5%, 6%, 7%, 8%, 9%, or 10%; 1-4% can be, for example, 1%, 2%, 3%, or 4%; 65-80% can be, for example, 65%, 66%, 68%, 70%, 72%, 74%, 75%, 76%, 78%, or 80%.

[0044] This invention adds a pore-forming agent to the raw materials for preparing polyurethane resin. The pore-forming agent decomposes and volatilizes during the preparation of synthetic leather, forming fine micropores on the surface of the synthetic leather, which gives the synthetic leather excellent water absorption properties without affecting its scratch resistance.

[0045] Preferably, the polyolefin polyol comprises hydroxyl-terminated polybutadiene and / or hydrogenated hydroxyl-terminated polybutadiene.

[0046] Preferably, the weight-average molecular weight of the polyolefin polyol is 2200-2500, for example, it can be 2200, 2300, 2400 or 2500.

[0047] Preferably, the isocyanate includes toluene diisocyanate and / or diphenylmethane diisocyanate.

[0048] Preferably, the pore-forming agent comprises tributyl citrate and / or acetyltributyl citrate.

[0049] Preferably, the chain extender includes an amine chain extender, and more preferably succinamide.

[0050] This invention uses amine chain extenders. Compared with alcohol chain extenders, which have obvious crystallinity, polyurethane resin containing amine chain extenders has weaker crystallinity and better foaming performance. This is reflected in the preparation process, where the less crystallized polyurethane resin has a slower curing speed, resulting in synthetic leather with uniform thickness, softer feel, and better water absorption.

[0051] Preferably, the solvent includes N,N -Dimethylformamide.

[0052] Preferably, the raw materials for preparing the polyurethane resin further include any one or a combination of at least two of the following: a terminator, an antioxidant, a polymerization inhibitor, a foaming agent, or an anti-tack and anti-blocking agent.

[0053] Preferably, based on the total mass of the raw materials for preparing polyurethane resin as 100%, the content of the terminator in the raw materials for preparing polyurethane resin is 0.01-0.03%, for example, it can be 0.01%, 0.015%, 0.02%, 0.025% or 0.03%, etc.

[0054] Preferably, based on the total mass of the raw materials for preparing polyurethane resin as 100%, the content of antioxidant in the raw materials for preparing polyurethane resin is 0.007-0.009%, for example, it can be 0.007%, 0.0075%, 0.008%, 0.0085% or 0.009%, etc.

[0055] Preferably, based on the total mass of the raw materials for preparing polyurethane resin as 100%, the content of the polymerization inhibitor in the raw materials for preparing polyurethane resin is 0.001-0.003%, for example, it can be 0.001%, 0.0015%, 0.002%, 0.0025% or 0.003%, etc.

[0056] Preferably, based on the total mass of the raw materials for preparing polyurethane resin as 100%, the content of foaming agent in the raw materials for preparing polyurethane resin is 1-4%, for example, it can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5% or 4%, etc.

[0057] Preferably, based on the total mass of the raw materials for preparing polyurethane resin as 100%, the content of the anti-tack and anti-blocking agent in the raw materials for preparing polyurethane resin is 0.01-0.03%, for example, it can be 0.01%, 0.015%, 0.02%, 0.025% or 0.03%, etc.

[0058] Preferably, the terminating agent comprises methanol.

[0059] Preferably, the antioxidant includes any one or a combination of at least two of hindered phenolic antioxidants, phosphite antioxidants, or thioester antioxidants.

[0060] Preferably, the polymerization inhibitor comprises phosphoric acid.

[0061] Preferably, the anti-tackifying agent comprises malic acid and / or phthalic anhydride.

[0062] Preferably, the foaming agent comprises glycerol polyether.

[0063] Preferably, the weight-average molecular weight of the glycerol polyether is 5000-7000, for example, it can be 5000, 5500, 6000, 6500 or 7000.

[0064] Preferably, the polyurethane resin is prepared by the following method, which includes the following steps:

[0065] (A) A mixture of bio-based polyester polyol, polyolefin polyol, antioxidant, phosphoric acid, a portion of isocyanate, and a portion of solvent is mixed and reacted.

[0066] (B) Add a chain extender, another portion of solvent, and another portion of isocyanate to the reaction system obtained in step (A) and carry out the reaction;

[0067] (C) Add a terminator, glycerol polyether, tributyl citrate and anti-tack additive to the reaction system obtained in step (B) and react to obtain the polyurethane resin.

[0068] Preferably, the reaction temperature in step (A) is 65-75°C, for example, it can be 65°C, 66°C, 68°C, 70°C, 72°C, 74°C or 75°C.

[0069] Preferably, the prepolymer viscosity of the reaction system in step (A) is 10-13 cps / 65°C, for example, it can be 10 cps / 65°C, 11 cps / 65°C, 12 cps / 65°C or 13 cps / 65°C, etc.

[0070] Preferably, the reaction temperature in step (B) is 65-75°C, for example, it can be 65°C, 66°C, 68°C, 70°C, 72°C, 74°C or 75°C.

[0071] Preferably, the viscosity of the reaction system in step (B) is 30-40 cps / 25°C, for example, it can be 30 cps / 25°C, 32 cps / 25°C, 34 cps / 25°C, 35 cps / 25°C, 36 cps / 25°C, 38 cps / 25°C or 40 cps / 25°C, etc.

[0072] Preferably, the reaction temperature in step (C) is 20-30°C, for example, it can be 20°C, 22°C, 24°C, 25°C, 26°C, 28°C or 30°C.

[0073] Preferably, the solid content of the reaction system in step (C) is 25-35%, for example, it can be 25%, 26%, 28%, 30%, 32%, 34% or 35%, etc., and the viscosity is 22-28 cps / 25℃, for example, it can be 22 cps / 25℃, 23 cps / 25℃, 24 cps / 25℃, 25 cps / 25℃, 26 cps / 25℃, 27 cps / 25℃ or 28 cps / 25℃, etc.

[0074] In a second aspect, the present invention provides a synthetic leather comprising a polyurethane coating layer containing the polyurethane resin described in the first aspect and a base fabric.

[0075] Preferably, the polyurethane coating layer comprises, by weight, 95-105 parts of the polyurethane resin described in the first aspect, 1-3 parts of color paste, 0.1-0.2 parts of leveling agent, and 50-70 parts of solvent.

[0076] Among them, 95-105 portions can be, for example, 95 portions, 96 portions, 97 portions, 98 portions, 99 portions, 100 portions, 101 portions, 102 portions, 103 portions, 104 portions, or 105 portions, etc.; 1-3 portions can be, for example, 1 portion, 1.5 portions, 2 portions, 2.5 portions, or 3 portions, etc.; 0.1-0.2 portions can be, for example, 0.1 portions, 0.12 portions, 0.14 portions, 0.15 portions, 0.16 portions, 0.18 portions, or 0.2 portions, etc.; 50-70 portions can be, for example, 50 portions, 55 portions, 60 portions, 65 portions, or 70 portions, etc.

[0077] Preferably, the leveling agent comprises a polyurethane leveling agent.

[0078] Preferably, the solvent includes N,N -Dimethylformamide.

[0079] This invention does not limit the selection of color pastes; different colors of color pastes can be added according to the synthetic leather colors required by the market.

[0080] Thirdly, the present invention provides a method for preparing synthetic leather as described in the second aspect, the method comprising the following steps:

[0081] (1) Mix polyurethane resin, color paste, leveling agent and solvent in proportion by weight to obtain polyurethane coating for later use;

[0082] The base fabric is pre-impregnated and then cured for later use;

[0083] (2) Apply polyurethane coating to the surface of the base fabric and cure it to obtain the synthetic leather.

[0084] Preferably, the prepreg treatment in step (1) involves coating the prepreg onto the surface of the base fabric and then pressing the surface of the base fabric with rollers.

[0085] Preferably, the prepreg treated with the prepreg includes Asahikawa Chemical's DX-30DP resin.

[0086] This invention pre-treats the base fabric by rolling it with pre-impregnated resin, which then enters the fibers of the base fabric and neutralizes the resin, giving the base fabric good elasticity and a fleshy feel.

[0087] Preferably, the curing in step (1) involves immersing the pre-impregnated base fabric in a solution containing 15-17% (e.g., 15%, 15.5%, 16%, 16.5%, or 17% by mass) of [a specific substance / material]. N,N The curing process is carried out in an aqueous solution of dimethylformamide for 10-20 minutes, such as 10 minutes, 12 minutes, 14 minutes, 16 minutes, 18 minutes, or 20 minutes.

[0088] Preferably, after curing in step (1), the process further includes pressing and ironing.

[0089] Preferably, the moisture content of the base fabric after compression and ironing is 40-50%, for example, it can be 40%, 42%, 44%, 46%, 48% or 50%, etc.

[0090] Preferably, the coating thickness in step (2) is 1-4 mm, for example, it can be 1 mm, 2 mm, 3 mm or 4 mm, etc.

[0091] Preferably, the curing in step (2) involves immersing the side of the base fabric coated with polyurethane paint in a solution containing 15-17% (e.g., 15%, 15.5%, 16%, 16.5%, or 17% by mass) of a solution. N,N The curing process is carried out in an aqueous solution of dimethylformamide for 10-20 minutes, such as 10 minutes, 12 minutes, 14 minutes, 16 minutes, 18 minutes, or 20 minutes.

[0092] This invention employs a curing method that slowly solidifies synthetic leather on the surface of a solution, by limiting... N,N The concentration of dimethylformamide aqueous solution results in synthetic leather with a uniform thickness, a softer feel, and superior foaming and water absorption properties.

[0093] Preferably, step (2) further includes pressing, washing and drying after curing.

[0094] Preferably, the drying temperature is 120-140℃, for example, it can be 120℃, 125℃, 130℃, 135℃ or 140℃, and the drying time is 15-20 min.

[0095] Thirdly, the present invention provides an application of synthetic leather as described in the second aspect as grip leather.

[0096] Compared with the prior art, the present invention has at least the following beneficial effects:

[0097] (1) The present invention designs the raw materials for the preparation of bio-based polyester polyol and polyurethane resin. Bio-based diol and bio-based dicarboxylic acid are used as raw materials. The prepared synthetic leather has a high bio-based content and good application prospects. By introducing small molecule branched diol into bio-based polyester polyol, the branched structure provides scratch resistance to the synthetic leather with polyurethane resin as the coating layer. The compounded polyolefin polyol reduces the crystallinity of polyurethane resin and gives the above synthetic leather a soft feel.

[0098] (2) In this invention, a pore-forming agent is added to the raw materials for preparing polyurethane resin. By decomposing and volatilizing the pore-forming agent during the preparation of synthetic leather, fine micropores are formed on the surface of synthetic leather, which further improves the water absorption performance of synthetic leather without affecting its scratch resistance.

[0099] (3) The preferred technical solution of the present invention uses amine chain extenders. Compared with alcohol chain extenders with obvious crystallinity, polyurethane resin containing amine chain extenders has weaker crystallinity and better foaming performance. In the preparation process, the polyurethane resin with weaker crystallinity has a slower curing speed, and the resulting synthetic leather has a uniform thickness, a softer feel, and better water absorption.

[0100] (4) The present invention uses a specific synthetic leather preparation method, which is simple, low in cost and energy consumption, and further improves product performance. Attached Figure Description

[0101] Figures 1 - 6 The figures show the water absorption properties of the synthetic leather prepared using Examples 1-6, respectively.

[0102] Figures 7 - 9 The figures show the water absorption performance test results of the synthetic leather prepared in Comparative Application Examples 2-3 and 5, respectively. Detailed Implementation

[0103] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following embodiments and application examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0104] The specific information of the materials used in the following specific embodiments of the present invention is as follows:

[0105] Hydroxyl-terminated polybutadiene diol was purchased from Wuxi Liten Chemical Co., Ltd., with a weight-average molecular weight of 2200-2500.

[0106] Glyceryl polyether, grade 3602, with a weight-average molecular weight of 3000~3400;

[0107] Colorant, blue pigment, purchased from Jiangxi Sanyue New Materials Co., Ltd.

[0108] Leveling agent, polyurethane leveling agent, brand name 9565, purchased from Jiangxi Sanyue New Materials Co., Ltd.

[0109] Antioxidant, brand name 1010, purchased from BASF Shanghai;

[0110] Prepreg, DX-30DP, purchased from Asahikawa Chemical.

[0111] Preparation Example 1

[0112] This preparation example provides a polyurethane resin and its preparation method. The raw materials for preparing the polyurethane resin include bio-based polyester polyol, hydroxyl-terminated polybutadiene diol, diphenylmethane diisocyanate, toluene diisocyanate, tri-n-butyl citrate, glycerol polyether, succinamide, malic acid, phosphoric acid, methanol, antioxidant 1010, and... N,N -Dimethylformamide.

[0113] The raw materials for preparing the bio-based polyester polyol include bio-based 1,5-pentanediol, bio-based 1,4-succinic acid, 2-butyl-2-ethyl-1,3-propanediol, and p-toluenesulfonic acid.

[0114] The preparation method of the bio-based polyester polyol includes the following steps:

[0115] (S1) Bio-based 1,5-pentanediol (2339 g), bio-based 1,4-succinic acid (2546 g) and 2-butyl-2-ethyl-1,3-propanediol (115 g) were mixed and reacted at 135 °C for 9 h under a nitrogen atmosphere of 0.3 L / min, and then the temperature was raised to 230 °C for 1 h.

[0116] (S2) The reaction system obtained in step (S1) was vacuum-treated at a vacuum degree of -0.05 MPa for 4 h, and then vacuum-treated at a vacuum degree of -0.08 MPa for 7 h until the acid value of the reaction system was 30 mg KOH / g.

[0117] (S3) Add 0.5 g of p-toluenesulfonic acid to the reaction system obtained in step (S2), and continue the reaction at 230°C and under a vacuum of -0.08 MPa until the acid value of the reaction system is 0.2 mgKOH / g and the hydroxyl value is 35 mgKOH / g. Stop the reaction, and then cool and filter to obtain the bio-based polyester polyol.

[0118] The preparation method of the polyurethane resin includes the following steps:

[0119] (A) The above-prepared bio-based polyester polyol (137 g), hydroxyl-terminated polybutadiene diol (50 g, weight average molecular weight 2200), antioxidant 1010 (0.1 g), phosphoric acid (0.02 g) and N,N Mix dimethylformamide (132 g) and then add toluene diisocyanate (11.5 g), and react at 70°C until the viscosity of the reaction system is 12 cps / 65°C;

[0120] (B) Add to the reaction system of step (A) N,NDimethylformamide (646 g), succinamide (25.5 g), and diphenylmethane diisocyanate (55 g) were reacted at 70 °C until the viscosity of the reaction system was 35 cps / 25 °C.

[0121] (C) Add methanol (0.3 g), tributyl citrate (17 g), glycerol polyether (37 g) and malic acid (0.3 g) to the reaction system obtained in step (B), and react at 25°C until the solid content of the reaction system is 30% and the viscosity is 25 cps / 25°C. Continue stirring for 1 h to obtain the polyurethane resin.

[0122] Preparation Example 2

[0123] This preparation example provides a polyurethane resin and its preparation method. The raw materials for preparing the polyurethane resin include bio-based polyester polyol, hydroxyl-terminated polybutadiene diol, diphenylmethane diisocyanate, tri-n-butyl citrate, succinamide, phthalic anhydride, phosphoric acid, methanol, antioxidant 1010, and... N,N -Dimethylformamide.

[0124] The raw materials for preparing the bio-based polyester polyol include bio-based 1,3-butanediol, bio-based sebacic acid, 2,4-diethyl-1,5-pentanediol, and stannous octoate.

[0125] The preparation method of the bio-based polyester polyol includes the following steps:

[0126] (S1) Bio-based 1,3-butanediol (1599 g), bio-based sebacic acid (3306 g) and 2,4-diethyl-1,5-pentanediol (94.6 g) were mixed and reacted at 140 °C for 7.5 h under a nitrogen atmosphere of 0.4 L / min, and then the temperature was raised to 230 °C for 1 h.

[0127] (S2) The reaction system obtained in step (S1) was vacuum-treated at a vacuum degree of -0.05 MPa for 4 h, and then vacuum-treated at a vacuum degree of -0.08 MPa for 7 h until the acid value of the reaction system was 30 mg KOH / g.

[0128] (S3) Add 0.35 g of stannous octoate to the reaction system obtained in step (S2), and continue the reaction at 230°C and under a vacuum of -0.08 MPa until the acid value of the reaction system is 0.4 mgKOH / g and the hydroxyl value is 37 mgKOH / g. Stop the reaction, and then cool and filter to obtain the bio-based polyester polyol.

[0129] The preparation method of the polyurethane resin includes the following steps:

[0130] (A) The above-prepared bio-based polyester polyol (147 g), hydroxyl-terminated polybutadiene diol (40 g, weight average molecular weight 2300), antioxidant 1010 (0.1 g), phosphoric acid (0.02 g) and N,N Mix dimethylformamide (136 g) and then add diphenylmethane diisocyanate (16.6 g), and react at 70°C until the viscosity of the reaction system is 13 cps / 65°C;

[0131] (B) Add to the reaction system of step (A) N,N Dimethylformamide (643 g), succinamide (24 g), and diphenylmethane diisocyanate (51.6 g) were reacted at 70 °C until the viscosity of the reaction system was 39 cps / 25 °C.

[0132] (C) Add methanol (0.3 g), tributyl citrate (37 g), glycerol polyether (17 g) and phthalic anhydride (0.3 g) to the reaction system obtained in step (B) and react at 25°C until the solid content of the reaction system is 30% and the viscosity is 28 cps / 25°C. Continue stirring for 1 h to obtain the polyurethane resin.

[0133] Preparation Example 3

[0134] This preparation example provides a polyurethane resin and its preparation method. The raw materials for preparing the polyurethane resin include bio-based polyester polyol, hydroxyl-terminated polybutadiene diol, diphenylmethane diisocyanate, tri-n-butyl citrate, succinamide, phthalic anhydride, phosphoric acid, methanol, antioxidant 1010, and... N,N- Dimethylformamide.

[0135] The raw materials for preparing the bio-based polyester polyol include bio-based 1,5-pentanediol, bio-based 1,3-butanediol, bio-based 1,4-succinic acid, bio-based sebacic acid, 2-butyl-2-ethyl-1,3-propanediol, and stannous octoate.

[0136] The preparation method of the bio-based polyester polyol includes the following steps:

[0137] (S1) Bio-based 1,5-pentanediol (885 g), bio-based 1,3-butanediol (766 g), bio-based 1,4-succinic acid (887 g), bio-based sebacic acid (1520 g) and 2-butyl-2-ethyl-1,3-propanediol (94.2 g) were mixed and reacted at 145 °C for 6 h under a nitrogen atmosphere of 0.6 L / min, and then the temperature was raised to 235 °C for 1 h.

[0138] (S2) The reaction system obtained in step (S1) was vacuum-treated at a vacuum degree of -0.05 MPa for 4 h, and then vacuum-treated at a vacuum degree of -0.08 MPa for 7 h until the acid value of the reaction system was 30 mg KOH / g.

[0139] (S3) Add 0.25 g of stannous octoate to the reaction system obtained in step (S2), and continue the reaction at 235°C and -0.08 MPa vacuum until the acid value of the reaction system is 0.8 mgKOH / g and the hydroxyl value is 39 mgKOH / g. Stop the reaction, and then cool and filter to obtain the bio-based polyester polyol.

[0140] The preparation method of the polyurethane resin includes the following steps:

[0141] (A) The above-prepared bio-based polyester polyol (157 g), hydroxyl-terminated polybutadiene diol (30 g, weight average molecular weight 2500), antioxidant 1010 (0.1 g), phosphoric acid (0.02 g) and N,N Mix dimethylformamide (136 g) and then add diphenylmethane diisocyanate (16.9 g), and react at 70°C until the viscosity of the reaction system is 11 cps / 65°C;

[0142] (B) Add to the reaction system of step (A) N,N Dimethylformamide (643 g), succinamide (24 g), and diphenylmethane diisocyanate (51.6 g) were reacted at 70 °C until the viscosity of the reaction system was 32 cps / 25 °C.

[0143] (C) Add methanol (0.3 g), tributyl citrate (27 g), glycerol polyether (27 g) and phthalic anhydride (0.3 g) to the reaction system obtained in step (B) and react at 25°C until the solid content of the reaction system is 30% and the viscosity is 22 cps / 25°C. Continue stirring for 1 h to obtain the polyurethane resin.

[0144] Preparation Example 4

[0145] This preparation example provides a polyurethane resin and its preparation method. The raw materials for preparing the polyurethane resin include bio-based polyester polyol, hydroxyl-terminated polybutadiene diol, diphenylmethane diisocyanate, toluene diisocyanate, tri-n-butyl citrate, glycerol polyether succinate, malic acid, phosphoric acid, methanol, antioxidant 1010, and... N,N -Dimethylformamide.

[0146] The raw materials for preparing the bio-based polyester polyol include bio-based 1,5-pentanediol, bio-based 1,4-succinic acid, 2-butyl-2-ethyl-1,3-propanediol, and p-toluenesulfonic acid.

[0147] The preparation method of the bio-based polyester polyol includes the following steps:

[0148] (S1) Bio-based 1,5-pentanediol (2580 g), bio-based 1,4-succinic acid (2383 g) and 2-butyl-2-ethyl-1,3-propanediol (37 g) were mixed and reacted at 135 °C for 9 h under a nitrogen atmosphere of 0.3 L / min, and then the temperature was raised to 230 °C for 1 h.

[0149] (S2) The reaction system obtained in step (S1) was vacuum-treated at a vacuum degree of -0.05 MPa for 4 h, and then vacuum-treated at a vacuum degree of -0.08 MPa for 7 h until the acid value of the reaction system was 30 mgKOH / g.

[0150] (S3) Add 0.5 g of p-toluenesulfonic acid to the reaction system obtained in step (S2), and continue the reaction at 230°C and under a vacuum of -0.08 MPa until the acid value of the reaction system is 0.2 mgKOH / g and the hydroxyl value is 35 mgKOH / g. Stop the reaction, and then cool and filter to obtain the bio-based polyester polyol.

[0151] The preparation method of the polyurethane resin includes the following steps:

[0152] (A) The above-prepared bio-based polyester polyol (137 g), hydroxyl-terminated polybutadiene diol (50 g, weight average molecular weight 2200), antioxidant 1010 (0.1 g), phosphoric acid (0.02 g) and N,N Mix dimethylformamide (132 g) and then add toluene diisocyanate (11.5 g), and react at 70°C until the viscosity of the reaction system is 12 cps / 65°C;

[0153] (B) Add to the reaction system of step (A) N,N Dimethylformamide (646 g), succinamide (25.5 g), and diphenylmethane diisocyanate (54.8 g) were reacted at 70 °C until the viscosity of the reaction system was 35 cps / 25 °C.

[0154] (C) Add methanol (0.3 g), tributyl citrate (17 g), glycerol polyether (37 g) and malic acid (0.3 g) to the reaction system obtained in step (B) and react at 25°C until the solid content of the reaction system is 30% and the viscosity is 25 cps / 25°C. Continue stirring for 1 h to obtain the polyurethane resin.

[0155] Preparation Example 5

[0156] This preparation example provides a polyurethane resin and its preparation method. The difference between this preparation example and Preparation Example 3 is that:

[0157] The preparation method of the polyurethane resin includes the following steps:

[0158] (A) The bio-based polyester polyol (125 g), hydroxyl-terminated polybutadiene diol (12 g, weight average molecular weight 2500), antioxidant 1010 (0.1 g), phosphoric acid (0.02 g), and... N,N Mix dimethylformamide (99.6 g) and then add toluene diisocyanate (12.3 g), and react at 70°C until the viscosity of the reaction system is 12 cps / 65°C;

[0159] (B) Add to the reaction system of step (A) N,N Dimethylformamide (678 g), succinamide (44.5 g), and diphenylmethane diisocyanate (95.8 g) were reacted at 70°C until the viscosity of the reaction system was 35 cps / 25°C.

[0160] (C) Add methanol (0.3 g), tributyl citrate (20 g), glycerol polyether (22 g) and malic acid (0.3 g) to the reaction system obtained in step (B) and react at 25°C until the solid content of the reaction system is 30% and the viscosity is 25 cps / 25°C. Continue stirring for 1 h to obtain the polyurethane resin.

[0161] Preparation Example 6

[0162] This preparation example provides a polyurethane resin and its preparation method. The difference between this preparation example and Preparation Example 3 is that:

[0163] The preparation method of the polyurethane resin includes the following steps:

[0164] (A) The bio-based polyester polyol (165 g), hydroxyl-terminated polybutadiene diol (66 g, weight average molecular weight 2500), antioxidant 1010 (0.1 g), phosphoric acid (0.02 g), and... N,NMix dimethylformamide (168 g) and then add toluene diisocyanate (21.2 g), and react at 70°C until the viscosity of the reaction system is 12 cps / 65°C;

[0165] (B) Add to the reaction system of step (A) N,N Dimethylformamide (610 g), succinamide (12 g), and diphenylmethane diisocyanate (25.8 g) were reacted at 70 °C until the viscosity of the reaction system was 35 cps / 25 °C.

[0166] (C) Add methanol (0.3 g), tributyl citrate (20 g), glycerol polyether (22 g) and malic acid (0.3 g) to the reaction system obtained in step (B) and react at 25°C until the solid content of the reaction system is 30% and the viscosity is 25 cps / 25°C. Continue stirring for 1 h to obtain the polyurethane resin.

[0167] Preparation Example 7

[0168] This preparation example provides a polyurethane resin and its preparation method, which differs from Preparation Example 1 in that: the chain extender succinamide is replaced with the chain extender ethylene glycol in an equal molar amount, while the amount of other components remains unchanged.

[0169] Preparation Example 8

[0170] This preparation example provides a polyurethane resin and its preparation method, which differs from Preparation Example 1 in that: in the preparation method of the bio-based polyester polyol, the amount of bio-based 1,5-pentanediol added is 2270 g, the amount of bio-based 1,4-succinic acid added is 2480 g, and the amount of 2-butyl-2-ethyl-1,3-propanediol added is 250 g, while the amount of other components remains unchanged.

[0171] Preparation Example 9

[0172] This preparation example provides a polyurethane resin and its preparation method, which differs from Preparation Example 1 in that: in the preparation method of the bio-based polyester polyol, the amount of bio-based 1,5-pentanediol added is 2387 g, the amount of bio-based 1,4-succinic acid added is 2598 g, and the amount of 2-butyl-2-ethyl-1,3-propanediol added is 15 g, while the amount of other components remains unchanged.

[0173] Comparative Preparation Example 1

[0174] This comparative preparation example provides a polyurethane resin and its preparation method, which differs from Preparation Example 1 in that: in the preparation method of the bio-based polyester polyol, 2-butyl-2-ethyl-1,3-propanediol is replaced with bio-based 1,3-butanediol in equal molar amounts, while the addition amounts of the remaining components remain unchanged.

[0175] Comparative Preparation Example 2

[0176] This comparative preparation example provides a polyurethane resin and its preparation method, which differs from Preparation Example 1 in that: in the preparation method of the bio-based polyester polyol, 2-butyl-2-ethyl-1,3-propanediol is replaced with bio-based 1,5-pentanediol in equal molar amounts, while the addition amounts of the remaining components remain unchanged.

[0177] Comparative preparation example 3

[0178] This comparative preparation example provides a polyurethane resin and its preparation method, which differs from Preparation Example 1 in that: in the preparation method of the polyurethane resin, the equimolar amount of terminal hydroxyl polybutadiene diol is replaced with the bio-based polyester polyol obtained in Preparation Example 1, while the amount of other components added remains unchanged.

[0179] Comparative preparation example 4

[0180] This comparative preparation example provides a polyurethane resin and its preparation method, which differs from Preparation Example 1 in that the raw materials for preparing the polyurethane resin do not contain tributyl citrate.

[0181] Application Example 1

[0182] This application example provides a synthetic leather and a method for preparing the same, the synthetic leather comprising a polyurethane coating layer containing the polyurethane resin obtained in Preparation Example 1 and a base fabric.

[0183] The polyurethane coating layer comprises, by weight, 100 parts of the polyurethane resin obtained in Preparation Example 1, 2 parts of color paste, 0.1 parts of leveling agent, and... N,N 60 parts of dimethylformamide.

[0184] The method for preparing the synthetic leather includes the following steps:

[0185] (1) Mix polyurethane resin, color paste, leveling agent and solvent in proportion by weight to obtain polyurethane coating for later use;

[0186] Take a 0.4 mm thick base fabric, immerse it in DX-30DP resin for pre-impregnation, and then place the pre-impregnated base fabric in a solution containing 17%... N,N The base fabric is cured in an aqueous solution of dimethylformamide for 15 minutes. After curing, the base fabric is then squeezed and ironed to achieve a moisture content of 45% before use.

[0187] (2) Apply polyurethane coating to the surface of the base fabric with a coating thickness of 2 mm, and place the coated base fabric on a substrate containing 17% polyurethane. N,NThe synthetic leather is cured in an aqueous solution of dimethylformamide for 15 minutes, followed by extrusion, washing, and drying at 120°C for 20 minutes to obtain the synthetic leather.

[0188] Application Example 2

[0189] This application example provides a synthetic leather and a method for preparing the same, the synthetic leather comprising a polyurethane coating layer containing the polyurethane resin obtained in Preparation Example 2 and a base fabric.

[0190] The polyurethane coating layer comprises, by weight, 100 parts of the polyurethane resin obtained in Preparation Example 2, 2 parts of color paste, 0.1 parts of leveling agent, and... N,N 60 parts of dimethylformamide.

[0191] The method for preparing the synthetic leather includes the following steps:

[0192] (1) Mix polyurethane resin, color paste, leveling agent and solvent in proportion by weight to obtain polyurethane coating for later use;

[0193] Take a 0.4 mm thick base fabric, immerse it in DX-30DP resin for prepreg treatment, and then place the prepreg base fabric in a solution containing 16%... N,N The base fabric is cured in an aqueous solution of dimethylformamide for 15 minutes. After curing, the base fabric is then squeezed and ironed to achieve a moisture content of 45% before use.

[0194] (2) Apply polyurethane coating to the surface of the base fabric with a coating thickness of 2 mm, and place the coated base fabric on a substrate containing 16% polyurethane. N,N The synthetic leather is cured in an aqueous solution of dimethylformamide for 15 minutes, followed by extrusion, washing, and drying at 130°C for 18 minutes to obtain the synthetic leather.

[0195] Application Example 3

[0196] This application example provides a synthetic leather and a method for preparing the same, the synthetic leather comprising a polyurethane coating layer containing the polyurethane resin obtained in Preparation Example 3 and a base fabric.

[0197] The polyurethane coating layer comprises, by weight, 100 parts of the polyurethane resin obtained in Preparation Example 3, 2 parts of color paste, 0.1 parts of leveling agent, and... N,N 60 parts of dimethylformamide.

[0198] The method for preparing the synthetic leather includes the following steps:

[0199] (1) Mix polyurethane resin, color paste, leveling agent and solvent in proportion by weight to obtain polyurethane coating for later use;

[0200] Take a 0.4 mm thick base fabric, immerse it in DX-30DP resin for pre-impregnation, and then place the pre-impregnated base fabric in a solution containing 17%... N,N The base fabric is cured in an aqueous solution of dimethylformamide for 15 minutes. After curing, the base fabric is then squeezed and ironed to achieve a moisture content of 45% before use.

[0201] (2) Apply polyurethane coating to the surface of the base fabric with a coating thickness of 2 mm, and place the coated base fabric on a substrate containing 17% polyurethane. N,N The synthetic leather is cured in an aqueous solution of dimethylformamide for 15 minutes. After curing, it is extruded, washed with water, and then dried at 140°C for 15 minutes to obtain the synthetic leather.

[0202] Application Example 4-9 and Comparative Application Example 1-4

[0203] Application Examples 4-9 and Comparative Application Examples 1-4 respectively provide a synthetic leather and its preparation method. The difference from Application Example 1 is that the polyurethane resin obtained in Preparation Example 1 is replaced with the polyurethane resin obtained in Preparation Examples 4-9 and Comparative Preparation Examples 1-4 in equal parts by weight.

[0204] Comparative Application Example 5

[0205] This comparative application example provides a synthetic leather and a method for preparing the same, the synthetic leather comprising a polyurethane coating layer containing the polyurethane resin obtained in Preparation Example 1 and a base fabric.

[0206] The polyurethane coating layer comprises, by weight, 100 parts of the polyurethane resin obtained in Preparation Example 1, 2 parts of color paste, 0.1 parts of leveling agent, and... N,N 60 parts of dimethylformamide.

[0207] The method for preparing the synthetic leather includes the following steps:

[0208] (1) Mix polyurethane resin, color paste, leveling agent and solvent in proportion by weight to obtain polyurethane coating for later use;

[0209] Take a 0.4 mm thick base fabric, immerse it in DX-30DP resin for pre-impregnation, and then place the pre-impregnated base fabric in a solution containing 20%... N,N The base fabric is cured in an aqueous solution of dimethylformamide for 15 minutes. After curing, the base fabric is then squeezed and ironed to achieve a moisture content of 45% before use.

[0210] (2) Apply polyurethane coating to the surface of the base fabric with a coating thickness of 2 mm, and place the coated base fabric on a substrate containing 20% ​​polyurethane. N,NThe synthetic leather is cured in an aqueous solution of dimethylformamide for 15 minutes, followed by extrusion, washing, and drying at 120°C for 20 minutes to obtain the synthetic leather.

[0211] Test methods

[0212] (1) Softness: The softness and hardness of synthetic leather were tested using a synthetic leather hardness and softness tester. The instrument was purchased from Dongguan Dazhong Instrument Co., Ltd., model DZ-326. The higher the reading on the instrument, the softer the synthetic leather feels.

[0213] (2) Scratch resistance, tested according to the national standard GB / T 44507-2024. The higher the scratch resistance rating, the worse the scratch resistance.

[0214] (3) Water absorption test: Use a straw to drop a drop of water on the surface of synthetic leather and record the time it takes for the water to penetrate into the synthetic leather. The longer the time, the worse the water absorption performance.

[0215] (4) Moisture content, calculated based on (wet cloth mass - dry cloth mass) / wet cloth mass;

[0216] (5) Both acid value and hydroxyl value were obtained by titration.

[0217] (6) Solid content, the test method refers to GB1725-1979;

[0218] (7) The molecular weight of bio-based polyols is calculated based on the hydroxyl value and acid value:

[0219] M=56.1×1000×(nCOOH+mOH) / (AV+OHV);

[0220] Hydroxyl value (OHV): The number of milligrams of KOH required to acetylate 1 gram of hydroxyl groups (-OH) in a sample, reflecting the hydroxyl content;

[0221] Acid value (AV): The number of milligrams of KOH required to neutralize free acid in 1 gram of sample, reflecting the content of carboxyl groups (-COOH).

[0222] nCOOH: The number of -COOH groups in a bio-based polyol;

[0223] mOH: The number of -OH groups in a bio-based polyol.

[0224] Test Results

[0225] Performance tests were conducted on the synthetic leather provided in corresponding use cases 1-9 and comparative application examples 1-5. The test results are shown in Table 1 below.

[0226] Table 1

[0227]

[0228] The test results show that:

[0229] (1) As can be seen from Application Examples 1 to 9, the synthetic leather prepared by the present invention can have at least two of the following properties: hand feel, scratch resistance and excellent water absorption. The appropriate product can be selected according to the needs of actual application.

[0230] (2) As can be seen from Application Examples 1 to 3, the synthetic leather provided by the preferred embodiment of the present invention has a good feel, scratch resistance and excellent water absorption. It is soft to the touch, has excellent scratch resistance and can complete the water absorption effect within 10 seconds.

[0231] (3) As can be seen from Application Example 1 and Application Example 4, when the amount of small molecule branched diol added in the present invention is too small, the polyurethane resin has strong crystallinity and the resulting synthetic leather is too hard.

[0232] (4) As can be seen from Application Example 1 and Application Examples 5-6, when the present invention limits the amount of amine chain extender added, the more chain extender there is, the stronger the crystallinity of the polyurethane resin, and the harder the synthetic leather is; the less chain extender there is, the poor foaming property of the polyurethane resin, and the poor hand feel and water absorption performance.

[0233] (5) As can be seen from Application Example 1 and Application Example 7, when the present invention uses succinamide chain extender, although the crystallinity of ethylene glycol is significantly weaker than that of amine chain extenders, the prepared synthetic leather has a soft feel and absorbs water quickly, but its weak crystallinity makes the synthetic leather less scratch-resistant.

[0234] (6) As can be seen from Application Examples 1 and 8-9, when the amount of small-molecule branched diols added in this invention is too large, the crystallinity of the synthetic leather is completely broken, making the prepared synthetic leather very soft, but at the same time, its scratch resistance is also poor. Conversely, as can be seen from Application Example 9, when the amount of small-molecule branched diols added is too small, the crystallinity of the synthetic leather is very strong, making the prepared synthetic leather very hard, and at the same time, its scratch resistance is also good, but its water absorption is poor.

[0235] (7) As can be seen from Application Example 1 and Comparative Application Examples 1-3, the present invention introduces small molecule branched diols and polyolefin polyols to give synthetic leather a softer feel and excellent scratch resistance.

[0236] (8) As can be seen from Application Example 1 and Comparative Application Example 4, when the polyurethane resin provided by the present invention does not contain a pore-forming agent, the polyurethane resin synthesis does not release gas during the drying process because there are no substances that decompose under heat. The resulting synthetic leather has a dense surface, a hard feel, good scratch resistance, but poor water absorption.

[0237] (10) As can be seen from Application Example 1 and Comparative Application Example 5, the present invention limits... N,N- The concentration of dimethylformamide aqueous solution is too high. Too high a concentration will cause the synthetic leather to have poor foaming properties, small pores, and a thicker epidermis. As a result, it will feel harder, have good scratch resistance, and poor water absorption.

[0238] Figures 1 - 6 The figures show the water absorption performance test results of the synthetic leather prepared in Examples 1-6. As can be seen from the figures, the synthetic leather provided by Examples 1-6 of the present invention has excellent water absorption performance, can absorb water within 10 seconds, and the water droplets do not smudge or spread.

[0239] Figures 7 - 9 The figures show the water absorption performance test results of the synthetic leather prepared in Comparative Application Examples 2-3 and 5, respectively. It can be seen from the figures that the synthetic leather provided by Comparative Application Examples 2-3 and 5 of the present invention has poor water absorption, takes a long time to absorb water, and the water droplets are significantly enlarged or smudged.

[0240] The applicant declares that 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 by, The raw materials for preparing the polyurethane resin include a bio-based polyester polyol, a polyolefin polyol, an isocyanate, a chain extender, a pore-forming agent, and a solvent; The raw materials for preparing the bio-based polyester polyol include the following components in percentage by mass: Bio-based dihydric alcohol 32-52%; Bio-based dihydric acid 47-66%; Small-molecule branched dihydric alcohol 0.5-3%; The molar ratio of the bio-based dihydric alcohol to the small-molecule branched dihydric alcohol is (26-33):1; The bio-based dihydric alcohol includes bio-based 1,5-pentanediol and / or bio-based 1,3-butanediol; The bio-based dihydric acid includes bio-based 1,4-succinic acid and / or bio-based sebacic acid; The small-molecule branched dihydric alcohol includes 2-butyl-2-ethyl-1,3-propanediol and / or 2,4-diethyl-1,5-pentanediol; The pore-forming agent includes tri-n-butyl citrate.

2. The polyurethane resin according to claim 1, characterized in that, The raw materials for preparing the bio-based polyester polyol further include a catalyst 0.005-0.01% in percentage by mass, based on the total mass of the raw materials for preparing the bio-based polyester polyol being 100%; The catalyst includes any one or a combination of at least two of p-toluenesulfonic acid, stannous octoate, or bismuth carboxylate.

3. The polyurethane resin according to claim 1 or 2, characterized in that, The raw materials for preparing the polyurethane resin include the following components in percentage by mass: Bio-based polyester polyol 11-15%; Polyolefin polyol 1-6%; Isocyanate 4-10%; Pore-forming agent 1-4%; Chain extender 1-4%; Solvent 65-80%; The polyolefin polyol includes hydroxyl-terminated polybutadiene and / or hydrogenated hydroxyl-terminated polybutadiene; The polyolefin polyol has a weight average molecular weight of 2200-2500; The isocyanate includes toluene diisocyanate and / or diphenylmethane diisocyanate; The chain extender includes an amine chain extender; The solvent comprises N,N dimethylformamide.

4. The polyurethane resin according to claim 3, characterized in that, The raw materials for preparing the polyurethane resin further include any one or a combination of at least two of a terminator, an antioxidant, a polymerization inhibitor, a blowing agent, or an anti-viscosity-reducing aid; And / or, the content of the terminator in the raw materials for preparing the polyurethane resin is 0.01-0.03% in percentage by mass, based on the total mass of the raw materials for preparing the polyurethane resin being 100%; And / or, the content of the antioxidant in the raw materials for preparing the polyurethane resin is 0.007-0.009% in percentage by mass, based on the total mass of the raw materials for preparing the polyurethane resin being 100%; And / or, the content of the polymerization inhibitor in the raw materials for preparing the polyurethane resin is 0.001-0.003% in percentage by mass, based on the total mass of the raw materials for preparing the polyurethane resin being 100%; And / or, the content of the blowing agent in the raw materials for preparing the polyurethane resin is 1-4% in percentage by mass, based on the total mass of the raw materials for preparing the polyurethane resin being 100%; And / or, the content of the anti-viscosity-reducing aid in the raw materials for preparing the polyurethane resin is 0.01-0.03% in percentage by mass, based on the total mass of the raw materials for preparing the polyurethane resin being 100%.

5. The polyurethane resin according to claim 4, characterized in that, The terminator includes methanol; The antioxidant includes any one or a combination of at least two of a hindered phenolic antioxidant, a phosphite antioxidant, or a thioester antioxidant; The polymerization inhibitor includes phosphoric acid; The anti-viscosity-reducing aid includes malic acid and / or phthalic anhydride; The blowing agent includes glycerol polyether. The weight average molecular weight of the glycerol polyether is 5000-7000.

6. A synthetic leather, characterized by, The synthetic leather comprises a polyurethane coating layer comprising the polyurethane resin of any one of claims 1-5 and a base fabric.

7. The synthetic leather according to claim 6, characterized in that, The polyurethane coating layer comprises the polyurethane resin of any one of claims 1-5 95-105 parts by weight, color paste 1-3 parts, leveling agent 0.1-0.2 parts, and solvent 50-70 parts; The leveling agent comprises a polyurethane leveling agent; The solvent comprises N,N dimethylformamide.

8. A method for producing the synthetic leather according to claim 7, characterized by, The preparation method of the synthetic leather comprises the following steps: (1) mixing the polyurethane resin, color paste, leveling agent and solvent according to the weight ratio to obtain a polyurethane coating, ready for use; After the base fabric is pre-impregnated, it is cured and ready for use; (2) coating the polyurethane coating on the surface of the base fabric, curing to obtain the synthetic leather; The solidification in step (1) is to immerse the pre-impregnated base fabric in a solution containing 15-17% by mass of N,N dimethylformamide water solution, and the solidification time is 10-20 min. The solidification in step (2) is carried out by immersing the one side of the base fabric coated with polyurethane coating in a solution containing 15-17% by mass of N,N - dimethylformamide water solution for 10-20 min.

9. The production method according to claim 8, characterized by, The pre-impregnation treatment in step (1) is to coat the prepreg on the surface of the base fabric, and then press the surface of the base fabric; After curing, step (1) further comprises the steps of extrusion and ironing; The moisture content of the base fabric after extrusion and ironing is 40-50%; The thickness of the coating in step (2) is 1-4 mm; After curing, step (2) further comprises the steps of extrusion, water washing and drying; The drying temperature is 120-140℃, and the drying time is 15-20 min.

10. Use of the synthetic leather of claim 6 as a handle leather.

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