A polyurethane skin material and a method for producing the same

Abstract

The application discloses a polyurethane skin material and a preparation method thereof. The skin material comprises the following components: (A) an isocyanate component, (B) an isocyanate-reactive component, wherein the surface tension of the isocyanate-reactive component is 20-35 mN / m. The skin material of the application is not prone to generating bubbles, and the prepared decorative skin has a good appearance and can be used in many fields such as automobile interior and exterior decoration, composite materials, seat imitation leather and the like.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane technology, specifically relating to a polyurethane skin material that can overcome surface defects caused by process bubbles and its preparation method. Background Technology

[0002] Traditional genuine leather products are widely used in footwear, home furnishings, automotive interiors and exteriors, and clothing due to their unique texture and aesthetics. However, their high price, limited styles, and complex maintenance procedures significantly restrict their application. In contrast, polyurethane leather materials offer advantages such as low cost, diverse styles, easy maintenance, and water and stain resistance, making them increasingly popular in the market.

[0003] However, existing polyurethane skin materials still have some problems in actual production. First, for two-component polyurethane systems, physical and mechanical bubbles inevitably mix into the polyurethane composition during the mixing reaction, or trace amounts of moisture in the polyurethane composition itself cause the gas generated during foaming to coalesce and float to the surface, which can cause defects such as bubbles and pinholes on the surface of the skin material, seriously affecting the production and application of decorative skin materials.

[0004] There are generally two existing solutions for improving the appearance defects of polyurethane skins: one is to use defoamers for physical defoaming, and the other is to accelerate the reaction process of the polyurethane system to suppress the rise of bubbles. However, both have their shortcomings. For the former, the defoamer takes too long to work, usually several hours, which greatly reduces production efficiency. For the latter, accelerating the reaction process of the polyurethane system speeds up the curing process and greatly shortens the process operation period, which limits the production of large-size skin products.

[0005] Therefore, how to create a polyurethane skin material and its preparation method that can effectively prevent bubbles and pinhole defects caused by mechanical foaming and floating in polyurethane systems, and improve the process tolerance and process stability of industrial production, has become a key research focus in the industry. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a polyurethane skin material and its preparation method, which can overcome surface defects caused by process bubbles, rapidly increase viscosity, has high foam stability, and greatly improves the process tolerance and process stability of industrial production of polyurethane skin.

[0007] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0008] A polyurethane skin material comprising the following components:

[0009] (A) Isocyanate component,

[0010] (B) Isocyanate reactive component,

[0011] The surface tension of the isocyanate reactive component is 20-35 mN / m;

[0012] Preferably, the isocyanate component is a compound containing isocyanate end groups in its molecular structure, including one or more of aromatic isocyanates, alicyclic isocyanates, and aliphatic isocyanates. Aromatic isocyanates offer high strength and toughness, and are readily available and inexpensive, making them widely used in industry. However, these aromatic isocyanates typically suffer from yellowing after prolonged exposure to light. Alicyclic and aliphatic isocyanates, on the other hand, are non-yellowing isocyanates, suitable for environments requiring high resistance to yellowing in the decorative surface. Those skilled in the art can choose according to their needs.

[0013] Preferably, the isocyanate component includes, but is not limited to: toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, naphthalene diisocyanate, terephthalic diisocyanate, 1,4-cyclohexane diisocyanate, phenylenediamine diisocyanate, cyclohexane diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, tetramethyl-m-phenylenediamine diisocyanate, norbornene diisocyanate, dimethylbiphenyl diisocyanate, methylcyclohexyl diisocyanate, tetramethylene diisocyanate, 2-methylpentamethylene diisocyanate, dodecamethyl diisocyanate, etc. Isocyanates, 4,4'-diisocyanate-3,3'-dimethyldicyclohexylmethane, 4,4'-diisocyanate-2,2-dicyclohexylpropane, poly(hexamethylene diisocyanate), octamethylene diisocyanate, toluene-α,4-diisocyanate, 2,4,6-trimethyl-1,3-phenylene diisocyanate, 4-chloro-6-methyl-1,3-phenylene diisocyanate, 1,4-butane diisocyanate, 1,8-octane diisocyanate, and other isocyanate derivatives such as modified isocyanates, prepolymers, dimers, and polymers (including trimerized or higher polymers), can be used alone or in combination.

[0014] In a preferred embodiment, component A is preferably a polyether-modified isocyanate, and preferably, the polyether-modified isocyanate has an NCO content of 15–31 wt% and a viscosity of 50–1000 mPa·s (25°C).

[0015] The isocyanate reactive component comprises the following components by mass fraction:

[0016] Polyol component 70wt.%-90wt.%

[0017] Chain extender 5 wt.% - 20 wt.%

[0018] Catalyst 0.01-1 wt.%

[0019] Thickener 0.2–2 wt.%

[0020] Surfactant 0.2-4 wt.%

[0021] Other additives: 0-10 wt.%.

[0022] Preferably, the polyol component includes polyether polyol and polyester polyol, and in this invention, the polyester polyol includes polyether carbonate polyol and polycarbonate polyol.

[0023] Preferably, the polyol component is a polyether polyol, such as a polyether polyol with a functionality of 2. Preferred initiators include ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, diethylene glycol, neopentyl glycol, etc.; for polyether polyols with a functionality of 3, preferred initiators include glycerol, trimethylolpropane, etc. The polyether polyol is preferably formed by ring-opening homopolymerization or copolymerization using propylene oxide, ethylene oxide, or a combination of both as monomers.

[0024] To obtain the appropriate surface tension range of the isocyanate reactive component required by the present invention, the addition of the polyol component can be adjusted by mixing various polyol components to achieve the appropriate surface tension.

[0025] In a preferred embodiment, the polyol component comprises polyether polyol 1 with an average functionality of 2-3 and a number-average molecular weight of 1000-8000 g / mol, and its amount is 70 wt.%-90 wt.% of the total mass of the isocyanate reactive component.

[0026] In a preferred embodiment, the isocyanate reactive component further comprises polyether polyol 2, with an average functionality of 2-3 and a number average molecular weight of 200-500 g / mol, and its amount is 0 wt.%-20 wt.% of the total mass of the isocyanate reactive component.

[0027] Preferably, the chain extender is a small molecule polyol with an average functionality of 2-3 and a molecular weight of 60-180 g / mol. Preferred examples include, but are not limited to, ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-pentanediol, hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, diethylene glycol, neopentyl glycol, glycerol, trimethylolpropane, etc. Such small molecule polyols can be used alone or in combination.

[0028] The catalyst comprises an organometallic catalyst and / or an amine catalyst, preferably selected from one or more of the following: triethylamine, tributylamine, triethylenediamine, N-ethylmorpholine, N,N,N',N'-tetramethyl-ethylenediamine, pentamethyldiethylene-triamine, N,N-methylaniline, N,N-dimethylaniline, tin(II) acetate, tin(II) octanoate, tin ethylhexanoate, tin laurate, dibutyltin oxide, dibutyltin dichloride, dibutyltin diacetate, dibutyltin maleate, dioctyltin diacetate, zinc isooctanoate, dibutyltin diacetate, dibutyltin maleate and dioctyltin diacetate, bismuth neodecanoate, bismuth 2-ethylhexanoate, and bismuth octanoate.

[0029] The thickener is a physical thickener or a chemical thickener. Preferred examples of physical thickeners include, but are not limited to, one or more of fumed silica, bentonite, and hydrogenated castor oil. Their function is to generate intermolecular forces such as hydrogen bonds in the polyurethane system, forming a three-dimensional network structure, increasing the viscosity of the system by several to tens of times. When an external force is applied to the system, the three-dimensional network structure is destroyed, causing the polyurethane system to become fluid to meet the requirements of the production process.

[0030] The chemical thickener is selected from active chain extenders having at least one free primary -NH2 group that can react with isocyanate, preferably an aromatic diamine. Preferred examples of the chemical thickener include, but are not limited to, one or more of diethyltoluenediamine, 4,4'-methylenebis(2-ethyl-6-methylaniline), and 4,4'-methylenebis(2,6-diethylaniline), with diethyltoluenediamine being particularly preferred. The function of the chemical thickener is to rapidly react with the isocyanate component to extend the chain, thereby rapidly increasing the viscosity of the polyurethane system.

[0031] It should be noted that at 25°C, the viscosity of the isocyanate reactive component and the isocyanate component after mechanical mixing for 10 seconds can reach 2000-8000 mPa·s. This viscosity range can suppress the movement of bubbles in the polyurethane composition while taking into account the flowability of the raw materials, which is mainly achieved through the action of thickener.

[0032] Specifically, adjusting the amount of catalyst, such as increasing the amount of catalyst, can help adjust the viscosity of the mixture of isocyanate reactive component and isocyanate component. To prevent the polyurethane composition from rapidly gelling and solidifying, thus losing its fluidity, the amount of catalyst used needs to be controlled so that, at 25°C, the gelation time after thorough mechanical mixing of the isocyanate component and isocyanate reactive component should be 15-60 seconds.

[0033] The surfactant comprises non-silicone surfactants and silicone surfactants, preferably silicone surfactants, and particularly preferably polyether-modified silicone surfactants. The surfactants are commercially available or can be prepared by known methods. Preferably, the amount used is 0.2-4 wt.% of the total weight of the isocyanate reactive components, more preferably 0.4-2 wt.%.

[0034] The addition of surfactants can effectively regulate the surface tension of isocyanate reactive components. The surface tension of isocyanate reactive components can be further regulated within the range of the present invention by adjusting the type and amount of surfactants added, so as to help prevent mechanical polymerization in the polyurethane composition.

[0035] The other additives are selected from one or more of the following: internal release agent, flame retardant, filler, pigment, antioxidant, light stabilizer, auxiliary antioxidant, hydrolytic stabilizer, bactericide and mildew inhibitor, leveling agent, wetting agent, reactive diluent, coupling agent, color paste, and dehydrating agent. Preferably, the amount of the additives is 4-10 wt% of the total weight of the isocyanate reactive components.

[0036] In this invention, the surface tension of the isocyanate reactive component is the result of mixing multiple components, and can be achieved by adjusting the content and type of the added components.

[0037] To achieve a decorative effect, the thickness of the polyurethane skin material prepared from it should be 0.5-3 mm.

[0038] Preferably, the isocyanate group to hydroxyl equivalent ratio in the isocyanate component and the isocyanate reactive component is 0.95-1.15, more preferably 0.98-1.08.

[0039] The present invention also provides a method for preparing the polyurethane skin material: mixing the isocyanate component and the isocyanate reactive component and reacting them to obtain the polyurethane skin material;

[0040] Preferably, the isocyanate component and the isocyanate reactive component are mixed using a high-pressure foaming machine. The mixing pressure of the high-pressure foaming machine is preferably 100-140 bar, and the dispensing rate is preferably 150-350 g / s. Using the mixing pressure and dispensing rate of this invention helps the isocyanate component and the isocyanate reactive component to react completely, facilitating thorough curing and maintaining the properties of the skin material.

[0041] The mold temperature is preferably 50-100℃, the material temperature is 25-40℃, and the reaction time is preferably 1-5 min.

[0042] The beneficial effects of this invention are as follows:

[0043] A rapid thickening and highly stable polyurethane system is provided. By controlling the surface tension of the isocyanate reactive component and the initial viscosity of the polyurethane reaction mixture, the two work together to uniformly and stably disperse the gas originally present in the system or the mechanical bubbles introduced by the process, without breaking and agglomerating to form large cavities or floating to form surface defects. This greatly improves the process tolerance and process stability of the industrial production of polyurethane skin materials. Detailed Implementation

[0044] To facilitate understanding of the present invention, the following description, in conjunction with embodiments, will further illustrate the invention. It should be understood that the following embodiments are merely for a better understanding of the invention and do not imply that the invention is limited to these embodiments.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The term "and / or" may be used herein to include any and all combinations of one or more of the associated listed items.

[0046] Main raw material sources

[0047] The raw materials used in the specific embodiments are as follows:

[0048] Isocyanate 1-1, WANNATE 8629, NCO 26wt%, Wanhua Chemical;

[0049] Isocyanate 1-2, WANNATE 8617, NCO 23wt%, Wanhua Chemical;

[0050] Polyether polyol 2-1, with a functionality of triglyceride, is polymerized from propylene oxide and ethylene oxide, with an ethylene oxide content of 90% and a number average molecular weight of 1000. Wanhua Chemical.

[0051] Polyether polyol 2-2, with a functionality of di, started by propylene glycol, ring-opening polymerization of propylene oxide, and end-capped by ethylene oxide, with a number average molecular weight of 8000, Wanhua Chemical.

[0052] Polyether polyol 2-3, functionality is tri, starting with glycerol, polymerized from propylene oxide and ethylene oxide, ethylene oxide content 65%, number average molecular weight 4000, Wanhua Chemical.

[0053] Polyether polyol 2-4, functionality is di, glycerol-initiated, propylene oxide polymerized, ethylene oxide-terminated, number average molecular weight 3000, Wanhua Chemical;

[0054] Polyester polyol 2-5, with a functionality of two, is obtained by polycondensation of adipic acid and ethylene glycol, with a number average molecular weight of 2000. Yantai Huada Chemical.

[0055] Polyester polyol 2-6, with a functionality of two, is obtained by polycondensation of adipic acid and 1,4-butanediol, with a number average molecular weight of 4000. Yantai Huada Chemical.

[0056] Polyether polyol 2-7, functionality is tri-, starting with glycerol, polymerized from propylene oxide and ethylene oxide, ethylene oxide content 60%, number average molecular weight 280, Jiahua Chemical;

[0057] Polyether polyol 2-8, functionality is tri-, starting with glycerol, polymerized with propylene oxide, number average molecular weight 400, Lanxing Dongda Chemical.

[0058] Polyester polyol 2-9, with a functionality of two, is obtained by polycondensation of adipic acid and ethylene glycol. The number average molecular weight is 450. It is commercially available from Yantai Huada Chemical.

[0059] Small molecule polyol 3-1, ethylene glycol, Henan Wanhai Chemical Co., Ltd.

[0060] Small molecule polyol 3-2,1,4-butanediol, Wanhua Chemical;

[0061] Small molecule polyols 3-3, glycerol, Yijia Chemical;

[0062] Thickener 1, diethyltoluenediamine, Yari Chemical;

[0063] Thickener 2, fumed silica, Delan Chemical;

[0064] Surfactant 1, B8002, Evonik;

[0065] Surfactant 2, B8409, Evonik;

[0066] Catalyst, Fomrez UL-29, Momentive;

[0067] Black paste, plus new materials.

[0068] Main testing methods

[0069] Surface tension test standard: GB / T 22237-2008.

[0070] Viscosity test: GB / T 12008.7-2010.

[0071] Gel test: Start timing from when the raw material is ejected from the nozzle of the high-pressure foaming machine. Gently touch the surface of the raw material with the end of a plastic dropper until the surface of the raw material no longer sticks to the dropper. This time is calibrated as the gel time of the raw material.

[0072] Appearance assessment: The appearance of polyurethane skin products is assessed by observing their outer surface.

[0073] Example

[0074] The formulation components and dosages of the examples are listed in Table 1, by weight.

[0075] Table 1. Formulations of the Examples (parts by weight)

[0076]

[0077]

[0078] Comparative Example

[0079] The components and dosages of the comparative formulation are listed in Table 2, by weight.

[0080] Table 2 Comparative Formulations (parts by weight)

[0081]

[0082]

[0083] After thoroughly mixing each unit of component B listed in Tables 1 and 2, the isocyanate reactive component was obtained. The weight ratio of the isocyanate component to the isocyanate component was calculated according to a hydroxyl equivalent ratio of 1.03. The mixture was then applied to a metal mold pre-coated with a release agent using a high-pressure spraying system. The mold temperature was set to 70°C, and the mold was opened and sampled after holding the pressure for 3 minutes to obtain the polyurethane skin. The appearance of the product was judged by observing its outer surface. The appearance results of the polyurethane skin products of the examples and comparative examples are listed in Tables 3 and 4, respectively.

[0084] Table 3 Appearance results of the epidermal products in the examples.

[0085]

[0086] Table 4. Appearance results of comparative example skin products

[0087] Skin thickness, mm 0.3 4.5 1.5 1.2 1.3 bubble many none less More none pinhole many none less none none filling good Difference good good good Is the surface oily? no no no no yes

[0088] It is readily understood that the above embodiments are merely illustrative examples for clear explanation and do not imply that the invention is limited thereto. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom remain within the scope of protection of this invention.

Claims

1. A polyurethane skin material, characterized in that, Includes the following components: (A) Isocyanate component, (B) Isocyanate reactive component, The surface tension of the isocyanate reactive component is 20-35 mN / m; The isocyanate reactive component comprises the following components by mass fraction: Polyol component 70wt.%-90wt.% Chain extender 5wt.%-20wt.% Catalyst 0.01-1wt%, Thickener 0.2~2wt%, Surfactant 0.2-4wt%, Other adjuvants: 0-10 wt%; At 25°C, the viscosity of the isocyanate reactive component and the isocyanate component after mechanical mixing can reach 2000-8000 mPa·s after 10 seconds of testing. At 25°C, the gelation time of the isocyanate component and the isocyanate reactive component after thorough mechanical mixing should be 15-60 seconds.

2. The polyurethane skin material according to claim 1, characterized in that, The isocyanate component comprises one or more of aromatic isocyanates, alicyclic isocyanates, and aliphatic isocyanates.

3. The polyurethane skin material according to claim 2, characterized in that, The isocyanate component is an aromatic isocyanate.

4. The polyurethane skin material according to claim 1, characterized in that, The isocyanate components include: toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, naphthalene diisocyanate, terephthalic diisocyanate, 1,4-cyclohexane diisocyanate, phenylenediamine diisocyanate, cyclohexane diisocyanate, trimethyl-1,6-hexamethylene diisocyanate, tetramethyl-m-phenylenediamine diisocyanate, norbornene diisocyanate, dimethylbiphenyl diisocyanate, methylcyclohexyl diisocyanate, tetramethylene diisocyanate, and 2-methylpentamethylene diisocyanate. The isocyanates, dodecyl diisocyanate, 4,4'-diisocyanate-3,3'-dimethyldicyclohexylmethane, 4,4'-diisocyanate-2,2-dicyclohexylpropane, poly(hexamethylene diisocyanate), octamethylene diisocyanate, toluene-α,4-diisocyanate, 2,4,6-trimethyl-1,3-phenylene diisocyanate, 4-chloro-6-methyl-1,3-phenylene diisocyanate, 1,4-butane diisocyanate, 1,8-octane diisocyanate, and one or more of the modified, prepolymer, dimer, and polymeric isocyanate derivatives of the above isocyanates.

5. The polyurethane skin material according to claim 4, characterized in that, Component A is a polyether-modified isocyanate.

6. The polyurethane skin material according to claim 5, characterized in that, The polyether-modified isocyanate has an NCO content of 15-31 wt% and a viscosity of 50-1000 mPa·s at 25°C.

7. The polyurethane skin material according to claim 1, characterized in that, The polyol components include polyether polyols and polyester polyols.

8. The polyurethane skin material according to claim 1, characterized in that, The polyol component is a polyether polyol.

9. The polyurethane skin material according to claim 8, characterized in that, The initiator of the polyether polyol is selected from one or more of ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, diethylene glycol, neopentyl glycol, glycerol, and trimethylolpropane.

10. The polyurethane skin material according to claim 1, characterized in that, The polyol component includes polyether polyol 1, with an average functionality of 2-3 and a number-average molecular weight of 1000-8000 g / mol, and its amount is 70 wt.%-90 wt.% of the total mass of the isocyanate reactive component.

11. The polyurethane skin material according to claim 10, characterized in that, The isocyanate reactive component further includes polyether polyol 2, with an average functionality of 2-3 and a number average molecular weight of 200-500 g / mol, and its amount is 0 wt.%-20 wt.% of the total mass of the isocyanate reactive component.

12. The polyurethane skin material according to claim 1, characterized in that, The chain extender is a small molecule polyol with an average functionality of 2-3 and a molecular weight of 60-180 g / mol.

13. The polyurethane skin material according to claim 1, characterized in that, The chain extender is one or more of the following: ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-pentanediol, hexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, diethylene glycol, neopentanediol, glycerol, and trimethylolpropane.

14. The polyurethane skin material according to claim 1, characterized in that, The catalyst comprises organometallic catalysts and / or amine catalysts.

15. The polyurethane skin material according to claim 14, characterized in that, The catalyst is selected from one or more of the following: triethylamine, tributylamine, triethylenediamine, N-ethylmorpholine, N,N,N',N'-tetramethyl-ethylenediamine, pentamethyldiethylene-triamine, N,N-methylaniline, N,N-dimethylaniline, tin(II) acetate, tin(II) octanoate, tin ethylhexanoate, tin laurate, dibutyltin oxide, dibutyltin dichloride, dibutyltin diacetate, dibutyltin maleate, dioctyltin diacetate, zinc isooctanoate, dibutyltin diacetate, dibutyltin maleate and dioctyltin diacetate, bismuth neodecanoate, bismuth 2-ethylhexanoate, and bismuth octanoate.

16. The polyurethane skin material according to claim 1, characterized in that, The thickener is a physical thickener or a chemical thickener.

17. The polyurethane skin material according to claim 16, characterized in that, Physical thickeners include one or more of fumed silica, bentonite, and hydrogenated castor oil.

18. The polyurethane skin material according to claim 16, characterized in that, The chemical thickener is selected from active chain extenders having at least one free primary amino group.

19. The polyurethane skin material according to claim 16, characterized in that, The chemical thickener is an aromatic diamine.

20. The polyurethane skin material according to claim 19, characterized in that, The chemical thickener includes one or more of diethyltoluenediamine, 4,4'-methylenebis(2-ethyl-6-methylaniline), and 4,4'-methylenebis(2,6-diethylaniline).

21. The polyurethane skin material according to claim 20, characterized in that, The chemical thickener is diethyltoluenediamine.

22. The polyurethane skin material according to claim 1, characterized in that, The surfactants include non-silicone surfactants and organosilicon surfactants.

23. The polyurethane skin material according to claim 22, characterized in that, The surfactant is an organosilicon surfactant.

24. The polyurethane skin material according to claim 23, characterized in that, The surfactant is a polyether-modified organosilicon surfactant.

25. The polyurethane skin material according to claim 1, characterized in that, The amount of the surfactant used is 0.4-2 wt% of the total weight of the isocyanate reactive components.

26. The polyurethane skin material according to claim 1, characterized in that, The other additives are selected from one or more of the following: internal release agent, flame retardant, filler, pigment, antioxidant, light stabilizer, auxiliary antioxidant, hydrolytic stabilizer, bactericide and mildew inhibitor, leveling agent, wetting agent, reactive diluent, coupling agent, color paste, and dehydrating agent.

27. The polyurethane skin material according to claim 1, characterized in that, The amount of the other additives is 4-10 wt% of the total weight of the isocyanate reactive components.

28. The polyurethane skin material according to claim 1, characterized in that, The thickness of the skin prepared by the polyurethane skin material is 0.5-3 mm.

29. The polyurethane skin material according to claim 1, characterized in that, The isocyanate component and the isocyanate reactive component have an isocyanate group to hydroxyl equivalent ratio of 0.95-1.

15.

30. The polyurethane skin material according to claim 29, characterized in that, The isocyanate component and the isocyanate reactive component have an isocyanate group to hydroxyl equivalent ratio of 0.98-1.

08.

31. The method for preparing the polyurethane skin material according to any one of claims 1-30, characterized in that, The isocyanate component and the isocyanate reactive component are mixed and reacted to obtain the polyurethane skin material.

32. The preparation method according to claim 31, characterized in that, The isocyanate component and the isocyanate reactive component are mixed by a high-pressure foaming machine, wherein the mixing pressure of the high-pressure foaming machine is 100-140 bar and the dispensing rate is 150-350 g / s.

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