One-shot polyurethane synthetic leather and polyurethane topcoat resin therefor

Abstract

The application discloses a one-step forming polyurethane synthetic leather and a polyurethane surface layer resin thereof, and belongs to the field of polyurethane synthetic leather. The polyurethane surface layer resin comprises the following raw materials: polyester polyol, polyether polyol PPG, polyether polyol PTMG, ethylene glycol, 1,4-butanediol, trimethylolpropane, toluene diisocyanate, diphenyl methane diisocyanate, modified glue particle, solvent and additive. The application limits the composition of the raw materials of the polyurethane synthetic leather and adopts a specific forming process, so that the prepared polyurethane synthetic leather is smooth in surface and free of defects such as fish eyes and pinholes, and has excellent softness and wear resistance. In the application, the raw material composition of the solid glue particle is limited, the polyurethane surface layer resin is modified, the prepared polyurethane synthetic leather does not need to be combined with other coating layers, and excellent softness and wear resistance can be achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of polyurethane synthetic leather preparation, and particularly relates to one-step forming polyurethane synthetic leather and a polyurethane surface layer resin thereof. BACKGROUND

[0002] The current production process of artificial synthetic leather is roughly as follows: after polyurethane resin fabric is prepared, the polyurethane resin fabric is coated on release paper, and then sent into an oven to dry the polyurethane resin fabric; the polyurethane adhesive resin is coated on the dried fabric, and according to the defined fastness requirements and the softness and hardness of the hand feeling, the polyurethane adhesive resin is semi-dried, then the base material is attached on the polyurethane adhesive resin, and then the release paper is completely dried and peeled off, and wound to obtain the required artificial synthetic leather; the artificial synthetic leather obtained by the above method has a complex operation process and high labor cost, and needs to be further improved. SUMMARY

[0003] The present application aims to overcome the shortcomings of the prior art, and provides a one-step forming polyurethane synthetic leather polyurethane surface layer resin, and another object is to provide a polyurethane synthetic leather prepared by using the above polyurethane surface layer resin.

[0004] The present application adopts the following technical scheme:

[0005] The one-step forming polyurethane synthetic leather polyurethane surface layer resin comprises the following raw materials in parts by weight: 20-40 parts of polyester polyol, 10-25 parts of polyether polyol PPG, 5-20 parts of polyether polyol PTMG, 0.5-5 parts of ethylene glycol, 0.5-5 parts of 1,4-butanediol, 0.05-0.3 parts of trimethylolpropane, 5-10 parts of toluene diisocyanate, 5-20 parts of diphenylmethane diisocyanate, 4-10 parts of modified rubber particles, 25-40 parts of solvent, and 0.3-3 parts of auxiliary.

[0006] Further, the modified rubber particles are composed of the following raw materials in parts by weight: 50 parts of thermoplastic polyurethane elastomer, 35-40 parts of styrene-acrylonitrile copolymer, 18-22 parts of epoxy resin, 3-7 parts of ABS compatibilizer, 2-4 parts of styrene-maleic anhydride graft copolymer, 0.3-0.7 parts of stearic acid, 1-1.5 parts of barium stearate, 1-2 parts of polyethylene wax, and 5-10 parts of calcined kaolin.

[0007] Further, the preparation method of the modified rubber particles comprises the following steps:

[0008] Step one, the required parts by weight of thermoplastic polyurethane elastomer, styrene-acrylonitrile copolymer and epoxy resin are pre-mixed in a high-speed mixer for 15 minutes to obtain a pre-mixture;

[0009] Step two, add the premix prepared in step one and the remaining raw materials into the internal mixer, mix and knead, discharge at 118℃, and stand at room temperature for more than 24 hours;

[0010] Step three, mix and knead the mixture after internal mixing on an open mill, and granulate to obtain the modified rubber particles.

[0011] Further, the solvent is one or more of N,N-dimethylformamide, dimethyl carbonate, and butanone.

[0012] Further, the auxiliary agent is composed of fluorine-based polyether modified polysiloxane, antioxidant, catalyst, and cellulose acetate in a mass ratio of 1:1.2-1.5:0.2-0.4:1-2.

[0013] Further, the viscosity of the polyurethane topcoat resin is 20,000-40,000 cps / 25℃, and the solid content is 60-75%.

[0014] The one-step formed polyurethane synthetic leather includes a base cloth and a polyurethane topcoat resin as described in any one of the above.

[0015] Further, the preparation method thereof includes the following steps:

[0016] Step one, preparing a polyurethane topcoat resin;

[0017] Step two, performing corona treatment on the surface of a release paper, then spraying an infiltration solution, and then coating the polyurethane topcoat resin prepared in step one;

[0018] Step three, laminating a base cloth on the top surface of the polyurethane topcoat resin, then sending it into an oven for drying at 120-130℃, and then peeling off the release paper to obtain the polyurethane synthetic leather.

[0019] Further, the infiltration solution is composed of the following raw materials in parts by weight: cellulose acetate 10-15 parts, fluorine-based polyether modified polysiloxane 5-8 parts, and butanone 80-90 parts.

[0020] Further, the preparation method of the polyurethane topcoat resin includes the following steps:

[0021] (1) Add polyester polyol, polyether polyol PPG, polyether polyol PTMG, and half of the solvent into a reaction kettle, stir at 50-60℃ until completely dissolved, then add toluene diisocyanate, heat to 75-85℃, and perform pre-polymerization for 0.5-1h;

[0022] (2) Add ethylene glycol, 1,4-butanediol and trimethylolpropane to the reactor, lower the temperature to 55°C, stir for 20-30 min, add modified colloids, diphenylmethane diisocyanate, additives and the remaining solvent, heat to 75-85°C and continue to react for 0.5-1 h; then lower the temperature to 50°C and stir for 1-2 h to obtain the polyurethane surface resin.

[0023] As can be seen from the above description of the present invention, compared with the prior art, the beneficial effects of the present invention are: the present invention, by limiting the composition of polyurethane synthetic leather raw materials and combining them with a specific molding process, makes the prepared polyurethane synthetic leather surface smooth and free of defects such as fish eyes and pinholes, while possessing excellent softness and wear resistance; wherein, by limiting the raw material composition of solid adhesive particles and modifying the polyurethane surface resin, the prepared polyurethane synthetic leather can achieve excellent softness and wear resistance without the need for other coatings.

[0024] The preparation method of polyurethane synthetic leather is specifically defined. Before coating the polyurethane surface layer resin, the release paper is first moistened by spraying an impregnation solution, and then the polyurethane surface layer resin is applied to ensure that the surface of the formed polyurethane synthetic leather is smooth and free from defects such as fish eyes and pinholes, thereby improving the yield. The raw material composition of the impregnation solution is specifically defined, along with the additives used in the polyurethane surface layer resin, to ensure that the polyurethane surface layer resin can be stably adhered to the release paper and does not affect subsequent peeling. Detailed Implementation

[0025] The present invention will be further described below through specific embodiments.

[0026] One-piece molded polyurethane synthetic leather, comprising a base fabric and a polyurethane surface resin coated on the base fabric; specifically, the viscosity of the polyurethane surface resin is 20,000-40,000 cps / 25℃; comprising the following raw materials in parts by weight: 20-40 parts polyester polyol, 10-25 parts polyether polyol PPG, 5-20 parts polyether polyol PTMG, 0.5-5 parts ethylene glycol, 0.5-5 parts 1,4-butanediol, 0.05-0.3 parts trimethylolpropane, 5-10 parts toluene diisocyanate, and diphenyl... The composition includes 5-20 parts methane diisocyanate, 4-10 parts modified granules, 25-40 parts solvent, and 0.3-3 parts additives. Among these, the molecular weight of the polyester polyol is 1000-4000 g / mol, specifically composed of polyester polyol PBA, polyester polyol PEA, or polyester polyol PBA and polyester polyol PEA in a mass ratio of 1:1; the molecular weight of polyether polyol PPG is 1000-3000 g / mol, and the molecular weight of polyether polyol PTMG is 2000 g / mol.

[0027] The modified granules are composed of the following raw materials in parts by weight: 50 parts thermoplastic polyurethane elastomer, 35-40 parts styrene-acrylonitrile copolymer, 18-22 parts epoxy resin, 3-7 parts ABS compatibilizer, 2-4 parts styrene-maleic anhydride graft copolymer, 0.3-0.7 parts stearic acid, 1-1.5 parts barium stearate, 1-2 parts polyethylene wax, and 5-10 parts calcined kaolin.

[0028] The solvent is one or more of N,N-dimethylformamide, dimethyl carbonate, and butanone.

[0029] The additives consist of fluoropolyether-modified polysiloxane, antioxidants, catalysts, and cellulose acetate in a mass ratio of 1:1.2-1.5:0.2-0.4:1-2.

[0030] Furthermore, the preparation method of modified colloidal particles includes the following steps:

[0031] Step 1: Premix the required weight parts of thermoplastic polyurethane elastomer, styrene-acrylonitrile copolymer, and epoxy resin in a high-speed mixer for 15 minutes to obtain a premix.

[0032] Step 2: Add the premix prepared in Step 1 and the remaining raw materials to the internal mixer and mix for 8 minutes. Then adjust the mixing temperature to 89°C, maintain it for 3 minutes, and turn the material over once. When the mixing temperature rises to 95°C, turn the material over a second time. When the mixing temperature rises to 102°C, turn the material over a third time. When the mixing temperature rises to 110°C, turn the material over a fourth time. When the mixing temperature rises to 118°C, turn the material over a fifth time, mix for another 1 minute, drain the adhesive, and let it stand at room temperature for at least 24 hours.

[0033] Step 3: The internally mixed mixture is then granulated on a two-roll mill to obtain the modified rubber granules.

[0034] A method for preparing one-piece molded polyurethane synthetic leather includes the following steps:

[0035] Step 1: Prepare the polyurethane surface layer resin;

[0036] Step 2: Perform corona treatment on the surface of the release paper, then spray with an impregnation solution, and then coat with the polyurethane surface resin prepared in Step 1.

[0037] Step 3: Lay the base fabric onto the top surface of the polyurethane surface resin, then put it into an oven and dry it at 120-130℃, and then peel off the release paper to obtain the polyurethane synthetic leather.

[0038] The preparation method of the polyurethane surface layer resin includes the following steps:

[0039] (1) Add polyester polyol, polyether polyol PPG, polyether polyol PTMG and half of the solvent into the reactor, stir at 50-60℃ until completely dissolved, add toluene diisocyanate, heat to 75-85℃, and carry out prepolymerization reaction for 0.5-1h.

[0040] (2) Add ethylene glycol, 1,4-butanediol and trimethylolpropane to the reactor, lower the temperature to 55°C, stir for 20-30 min, add modified colloids, diphenylmethane diisocyanate, additives and the remaining solvent, heat to 75-85°C and continue to react for 0.5-1 h; then lower the temperature to 50°C and stir for 1-2 h to obtain the polyurethane surface resin.

[0041] The impregnation solution is composed of the following raw materials in parts by weight: 10-15 parts cellulose acetate, 5-8 parts fluoropolyether modified polysiloxane, and 80-90 parts methyl ethyl ketone.

[0042] Example 1

[0043] One-piece molded polyurethane synthetic leather includes a base fabric and a polyurethane surface resin coated on the base fabric; specifically, the viscosity of the polyurethane surface resin is 20000 cps / 25℃; it includes the following raw materials in parts by weight: 20 parts polyester polyol, 25 parts polyether polyol PPG, 5 parts polyether polyol PTMG, 0.5 parts ethylene glycol, 5 parts 1,4-butanediol, 0.05 parts trimethylolpropane, 10 parts toluene diisocyanate, 5 parts diphenylmethane diisocyanate, 4 parts modified granules, 25 parts solvent, and 0.3 parts additives; wherein, the molecular weight of the polyester polyol is 1000 g / mol, specifically composed of polyester polyol PBA, polyester polyol PEA, or polyester polyol PBA and polyester polyol PEA in a 1:1 mass ratio; the molecular weight of polyether polyol PPG is 3000 g / mol, and the molecular weight of polyether polyol PTMG is 2000 g / mol.

[0044] The modified granules are composed of the following raw materials in parts by weight: 50 parts thermoplastic polyurethane elastomer, 35 parts styrene-acrylonitrile copolymer, 22 parts epoxy resin, 3 parts ABS compatibilizer, 4 parts styrene-maleic anhydride graft copolymer, 0.3 parts stearic acid, 1.5 parts barium stearate, 1 part polyethylene wax, and 10 parts calcined kaolin.

[0045] The solvent is N,N-dimethylformamide.

[0046] The additives consist of fluoropolyether-modified polysiloxane, antioxidant, catalyst, and cellulose acetate in a mass ratio of 1:1.2:0.4:1.

[0047] Furthermore, the preparation method of modified colloidal particles includes the following steps:

[0048] Step 1: Premix the required weight parts of thermoplastic polyurethane elastomer, styrene-acrylonitrile copolymer, and epoxy resin in a high-speed mixer for 15 minutes to obtain a premix.

[0049] Step 2: Add the premix prepared in Step 1 and the remaining raw materials to the internal mixer and mix for 8 minutes. Then adjust the mixing temperature to 89°C, maintain it for 3 minutes, and turn the material over once. When the mixing temperature rises to 95°C, turn the material over a second time. When the mixing temperature rises to 102°C, turn the material over a third time. When the mixing temperature rises to 110°C, turn the material over a fourth time. When the mixing temperature rises to 118°C, turn the material over a fifth time, mix for another 1 minute, drain the adhesive, and let it stand at room temperature for at least 24 hours.

[0050] Step 3: The internally mixed mixture is then granulated on a two-roll mill to obtain the modified rubber granules.

[0051] A method for preparing one-piece molded polyurethane synthetic leather includes the following steps:

[0052] Step 1: Prepare the polyurethane surface layer resin;

[0053] Step 2: Perform corona treatment on the surface of the release paper, then spray with an impregnation solution, and then coat with the polyurethane surface resin prepared in Step 1.

[0054] Step 3: Lay the base fabric onto the top surface of the polyurethane surface resin, then put it into an oven and dry it at 120°C. Finally, peel off the release paper to obtain the polyurethane synthetic leather.

[0055] The preparation method of the polyurethane surface layer resin includes the following steps:

[0056] (1) Add polyester polyol, polyether polyol PPG, polyether polyol PTMG and half of the solvent into the reactor, stir at 50°C until completely dissolved, add toluene diisocyanate, heat to 75°C, and carry out prepolymerization reaction for 1 hour.

[0057] (2) Add ethylene glycol, 1,4-butanediol and trimethylolpropane to the reactor, lower the temperature to 55°C, stir for 20 min, add modified colloids, diphenylmethane diisocyanate, additives and the remaining solvent, heat to 75°C and continue to react for 1 h; then lower the temperature to 50°C and stir for 2 h to obtain the polyurethane surface resin.

[0058] The impregnation solution is composed of the following raw materials in parts by weight: 10 parts cellulose acetate, 8 parts fluoropolyether modified polysiloxane, and 80 parts methyl ethyl ketone.

[0059] Example 2

[0060] One-piece molded polyurethane synthetic leather includes a base fabric and a polyurethane surface resin coated on the base fabric; specifically, the viscosity of the polyurethane surface resin is 40000 cps / 25℃; it includes the following raw materials in parts by weight: 40 parts polyester polyol, 10 parts polyether polyol PPG, 20 parts polyether polyol PTMG, 5 parts ethylene glycol, 0.5 parts 1,4-butanediol, 0.3 parts trimethylolpropane, 5 parts toluene diisocyanate, 20 parts diphenylmethane diisocyanate, 10 parts modified granules, 40 parts solvent, and 3 parts additives; wherein, the molecular weight of the polyester polyol is 4000 g / mol, specifically composed of polyester polyol PBA, polyester polyol PEA, or polyester polyol PBA and polyester polyol PEA in a 1:1 mass ratio; the molecular weight of polyether polyol PPG is 1000 g / mol, and the molecular weight of polyether polyol PTMG is 2000 g / mol.

[0061] The modified granules are composed of the following raw materials in parts by weight: 50 parts thermoplastic polyurethane elastomer, 40 parts styrene-acrylonitrile copolymer, 18 parts epoxy resin, 7 parts ABS compatibilizer, 2 parts styrene-maleic anhydride graft copolymer, 0.7 parts stearic acid, 1 part barium stearate, 2 parts polyethylene wax, and 5 parts calcined kaolin.

[0062] The solvent is butanone.

[0063] The additives consist of fluoropolyether-modified polysiloxane, antioxidant, catalyst, and cellulose acetate in a mass ratio of 1:1.5:0.2:2.

[0064] Furthermore, the preparation method of modified colloidal particles includes the following steps:

[0065] Step 1: Premix the required weight parts of thermoplastic polyurethane elastomer, styrene-acrylonitrile copolymer, and epoxy resin in a high-speed mixer for 15 minutes to obtain a premix.

[0066] Step 2: Add the premix prepared in Step 1 and the remaining raw materials to the internal mixer and mix for 8 minutes. Then adjust the mixing temperature to 89°C, maintain it for 3 minutes, and turn the material over once. When the mixing temperature rises to 95°C, turn the material over a second time. When the mixing temperature rises to 102°C, turn the material over a third time. When the mixing temperature rises to 110°C, turn the material over a fourth time. When the mixing temperature rises to 118°C, turn the material over a fifth time, mix for another 1 minute, drain the adhesive, and let it stand at room temperature for at least 24 hours.

[0067] Step 3: The internally mixed mixture is then granulated on a two-roll mill to obtain the modified rubber granules.

[0068] A method for preparing one-piece molded polyurethane synthetic leather includes the following steps:

[0069] Step 1: Prepare the polyurethane surface layer resin;

[0070] Step 2: Perform corona treatment on the surface of the release paper, then spray with an impregnation solution, and then coat with the polyurethane surface resin prepared in Step 1.

[0071] Step 3: Lay the base fabric onto the top surface of the polyurethane surface resin, then put it into an oven and dry it at 130°C. Finally, peel off the release paper to obtain the polyurethane synthetic leather.

[0072] The preparation method of the polyurethane surface layer resin includes the following steps:

[0073] (1) Add polyester polyol, polyether polyol PPG, polyether polyol PTMG and half of the solvent into the reactor, stir at 60°C until completely dissolved, add toluene diisocyanate, heat to 85°C, and carry out prepolymerization reaction for 0.5h.

[0074] (2) Add ethylene glycol, 1,4-butanediol and trimethylolpropane to the reactor, lower the temperature to 55°C, stir for 30 min, add modified colloids, diphenylmethane diisocyanate, additives and the remaining solvent, heat to 85°C and continue to react for 0.5 h; then lower the temperature to 50°C and stir for 1 h to obtain the polyurethane surface resin.

[0075] The impregnation solution is composed of the following raw materials in parts by weight: 15 parts cellulose acetate, 5 parts fluoropolyether modified polysiloxane, and 90 parts methyl ethyl ketone.

[0076] Example 3

[0077] One-piece molded polyurethane synthetic leather includes a base fabric and a polyurethane surface resin coated on the base fabric; specifically, the viscosity of the polyurethane surface resin is 30000 cps / 25℃; it includes the following raw materials in parts by weight: 30 parts polyester polyol, 18 parts polyether polyol PPG, 12 parts polyether polyol PTMG, 3.2 parts ethylene glycol, 2.7 parts 1,4-butanediol, 0.16 parts trimethylolpropane, 7 parts toluene diisocyanate, 12 parts diphenylmethane diisocyanate, 7 parts modified granules, 32 parts solvent, and 1.8 parts additives; wherein, the molecular weight of the polyester polyol is 2000 g / mol, specifically composed of polyester polyol PBA, polyester polyol PEA, or polyester polyol PBA and polyester polyol PEA in a 1:1 mass ratio; the molecular weight of polyether polyol PPG is 2000 g / mol, and the molecular weight of polyether polyol PTMG is 2000 g / mol.

[0078] The modified granules are composed of the following raw materials in parts by weight: 50 parts thermoplastic polyurethane elastomer, 37 parts styrene-acrylonitrile copolymer, 20 parts epoxy resin, 5 parts ABS compatibilizer, 3 parts styrene-maleic anhydride graft copolymer, 0.5 parts stearic acid, 1.2 parts barium stearate, 1.5 parts polyethylene wax, and 7 parts calcined kaolin.

[0079] The solvent is composed of N,N-dimethylformamide and dimethyl carbonate in a volume ratio of 1:1.

[0080] The additives consist of fluoropolyether-modified polysiloxane, antioxidant, catalyst, and cellulose acetate in a mass ratio of 1:1.3:0.3:1.5.

[0081] Furthermore, the preparation method of modified colloidal particles includes the following steps:

[0082] Step 1: Premix the required weight parts of thermoplastic polyurethane elastomer, styrene-acrylonitrile copolymer, and epoxy resin in a high-speed mixer for 15 minutes to obtain a premix.

[0083] Step 2: Add the premix prepared in Step 1 and the remaining raw materials to the internal mixer and mix for 8 minutes. Then adjust the mixing temperature to 89°C, maintain it for 3 minutes, and turn the material over once. When the mixing temperature rises to 95°C, turn the material over a second time. When the mixing temperature rises to 102°C, turn the material over a third time. When the mixing temperature rises to 110°C, turn the material over a fourth time. When the mixing temperature rises to 118°C, turn the material over a fifth time, mix for another 1 minute, drain the adhesive, and let it stand at room temperature for at least 24 hours.

[0084] Step 3: The internally mixed mixture is then granulated on a two-roll mill to obtain the modified rubber granules.

[0085] A method for preparing one-piece molded polyurethane synthetic leather includes the following steps:

[0086] Step 1: Prepare the polyurethane surface layer resin;

[0087] Step 2: Perform corona treatment on the surface of the release paper, then spray with an impregnation solution, and then coat with the polyurethane surface resin prepared in Step 1.

[0088] Step 3: Lay the base fabric onto the top surface of the polyurethane surface resin, then put it into an oven and dry it at 125°C. Finally, peel off the release paper to obtain the polyurethane synthetic leather.

[0089] The preparation method of the polyurethane surface layer resin includes the following steps:

[0090] (1) Add polyester polyol, polyether polyol PPG, polyether polyol PTMG and half of the solvent into the reactor, stir at 55°C until completely dissolved, add toluene diisocyanate, heat to 80°C, and carry out prepolymerization reaction for 0.8h.

[0091] (2) Add ethylene glycol, 1,4-butanediol and trimethylolpropane to the reactor, lower the temperature to 55°C, stir for 25 min, add modified colloids, diphenylmethane diisocyanate, additives and the remaining solvent, heat to 80°C and continue to react for 0.7 h; then lower the temperature to 50°C and stir for 1.5 h to obtain the polyurethane surface resin.

[0092] The impregnation solution is composed of the following raw materials in parts by weight: 12 parts cellulose acetate, 6 parts fluoropolyether modified polysiloxane, and 85 parts methyl ethyl ketone.

[0093] Comparative Example 1

[0094] Its raw material composition and preparation method are basically the same as those in Example 3, except that the polyurethane surface resin does not contain solid particles.

[0095] Comparative Example 2

[0096] Its raw material composition and preparation method are basically the same as those in Example 3, the difference being: the preparation method of one-time molding polyurethane synthetic leather includes the following steps:

[0097] Step 1: Prepare the polyurethane surface layer resin;

[0098] Step 2: Perform corona treatment on the surface of the release paper, and then coat it with the polyurethane surface layer resin prepared in Step 1.

[0099] Step 3: Lay the base fabric onto the top surface of the polyurethane surface resin, then put it into an oven and dry it at 125°C. Finally, peel off the release paper to obtain the polyurethane synthetic leather.

[0100] Comparative Example 3

[0101] Commercially available polyurethane synthetic leather is used, comprising, from top to bottom, a base fabric, a polyurethane adhesive resin, and a polyurethane surface resin.

[0102] Polyurethane synthetic leather was obtained from Examples 1-3 and Comparative Examples 1-3, and the following data were obtained through corresponding tests:

[0103] Among them, abrasion resistance: the synthetic leather samples were subjected to Taber abrasion resistance test under test conditions of 1KG pressure and H-18 grinding wheel.

[0104] Table 1 Test Data for Each Embodiment

[0105]

[0106] As can be seen from the table above, this invention, by limiting the raw materials of polyurethane synthetic leather and combining them with a specific molding process, makes the prepared polyurethane synthetic leather have a smooth surface, free from defects such as fish eyes and pinholes, while possessing excellent softness and wear resistance. In particular, by limiting the raw material composition of solid adhesive particles and modifying the polyurethane surface resin, the prepared polyurethane synthetic leather can achieve excellent softness and wear resistance without the need for other coatings.

[0107] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent application and the contents of the specification of the present invention should still fall within the scope of the patent of the present invention.

Claims

1. A one-piece molded polyurethane synthetic leather, characterized in that: Its preparation method includes the following steps: Step 1: Prepare the polyurethane surface layer resin; Step 2: Perform corona treatment on the surface of the release paper, then spray with an impregnation solution, and then coat with the polyurethane surface resin prepared in Step 1. Step 3: Lay the base fabric onto the top surface of the polyurethane surface resin, then put it into an oven and dry it at 120-130℃, and then peel off the release paper to obtain the polyurethane synthetic leather. The polyurethane surface resin comprises the following raw materials in parts by weight: 20-40 parts polyester polyol, 10-25 parts polyether polyol PPG, 5-20 parts polyether polyol PTMG, 0.5-5 parts ethylene glycol, 0.5-5 parts 1,4-butanediol, 0.05-0.3 parts trimethylolpropane, 5-10 parts toluene diisocyanate, 5-20 parts diphenylmethane diisocyanate, 4-10 parts modified granules, 25-40 parts solvent, and 0.3-3 parts additives; The modified granules are composed of the following raw materials in parts by weight: 50 parts thermoplastic polyurethane elastomer, 35-40 parts styrene-acrylonitrile copolymer, 18-22 parts epoxy resin, 3-7 parts ABS compatibilizer, 2-4 parts styrene-maleic anhydride graft copolymer, 0.3-0.7 parts stearic acid, 1-1.5 parts barium stearate, 1-2 parts polyethylene wax, and 5-10 parts calcined kaolin. The additive is composed of fluoropolyether-modified polysiloxane, antioxidant, catalyst, and cellulose acetate in a mass ratio of 1:1.2-1.5:0.2-0.4:1-2. The impregnation solution is composed of the following raw materials in parts by weight: 10-15 parts cellulose acetate, 5-8 parts fluoropolyether modified polysiloxane, and 80-90 parts methyl ethyl ketone.

2. The one-piece molded polyurethane synthetic leather according to claim 1, characterized in that: The method for preparing the modified colloidal particles includes the following steps: Step 1: Premix the required weight parts of thermoplastic polyurethane elastomer, styrene-acrylonitrile copolymer, and epoxy resin in a high-speed mixer for 15 minutes to obtain a premix. Step 2: Add the premix prepared in Step 1 and the remaining raw materials to the internal mixer, mix and knead, remove the glue at 118°C, and let stand at room temperature for more than 24 hours. Step 3: The internally mixed mixture is then granulated on a two-roll mill to obtain the modified rubber granules.

3. The one-piece molded polyurethane synthetic leather according to claim 1, characterized in that: The solvent is one or more of N,N-dimethylformamide, dimethyl carbonate, and butanone.

4. The one-piece molded polyurethane synthetic leather according to claim 1, characterized in that: The viscosity of the polyurethane surface resin is 20,000-40,000 cps / 25℃, and the solid content is 60-75%.

5. The one-piece molded polyurethane synthetic leather according to claim 1, characterized in that: The preparation method of the polyurethane surface layer resin includes the following steps: (1) Add polyester polyol, polyether polyol PPG, polyether polyol PTMG and half of the solvent into the reactor, stir at 50-60℃ until completely dissolved, add toluene diisocyanate, heat to 75-85℃, and carry out prepolymerization reaction for 0.5-1h. (2) Add ethylene glycol, 1,4-butanediol and trimethylolpropane to the reactor, lower the temperature to 55°C, stir for 20-30 min, add modified colloids, diphenylmethane diisocyanate, additives and the remaining solvent, heat to 75-85°C and continue to react for 0.5-1 h; then lower the temperature to 50°C and stir for 1-2 h to obtain the polyurethane surface resin.

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