Preparation method for preparing high-physical-property polyurethane synthetic leather with assistance of supercritical CO2 foaming method
The preparation of polyurethane synthetic leather through supercritical CO2 foaming method solves the problem of stiffness and rigidity of plastic and feel, and achieves the effect of softness and the stability of the auxiliary.
Patent Information
- Application Number
- CN202411585140.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-07
- Publication Date
- 2025-01-28
AI Technical Summary
The existing two-component solvent-free polyurethane synthetic leather has problems of plastic feeling and stiffness in the hand, which limits its development and promotion.
Using supercritical CO2 foaming method to assist preparation of high -object polyurethane synthesis leather, through the synergy of supercritical fluids to mix more uniform solvents A/B material, add additives such as flame retardants, light stabilizers, hydrolytic stabilizers to the supercritical to the supercritical In CO2, it is dissolved and stayed in the gas nucleus to avoid precipitating the auxiliary.
The sense of softness of polyurethane synthetic leather is achieved, and effectively prevents the additive from precipitating the surface of the synthetic leather, which improves the quality and stability of the synthetic leather.
Smart Images
Figure BDA0005124108510000051 
Figure BDA0005124108510000052
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of polyurethane synthetic leather, and particularly relates to a method for preparing high-property polyurethane synthetic leather by using a supercritical CO2 foaming method. Background Art
[0002] Supercritical fluid microporous foaming generally uses CO2 or N2 as a physical foaming agent. CO2 and N2 have stable chemical properties, low prices, are non-toxic and harmless, and are environmentally friendly; the critical pressure and temperature of supercritical CO2 and N2 are relatively mild and easy to achieve, and have good solubility in polymers, strong diffusion ability, and are easy to control. They can be mixed and dissolved with a variety of coating components, and the solubility and viscosity can be changed by adjusting the temperature and pressure; SCF foaming technology can make the gas dispersed evenly and produce uniform fine-porous structure foam, which can significantly improve mechanical properties and low density. It has the benefit of carbon synergistic emission reduction, and can use carbon dioxide in industrial waste gas as raw material to reduce greenhouse gas emissions.
[0003] Two-component solvent-free polyurethane synthetic leather has the advantages of strong leather feel and good durability, but its plastic feel and stiff feel have become important factors restricting its development and promotion. The supercritical fluid pressurization system can control the size of the foaming holes and the foaming ratio. The high temperature and high pressure system can make the two components evenly mixed, the film leveling is better, and the feel will be softer.
[0004] Most additives are added to materials or products during processing, but as additives, they often precipitate on the surface of synthetic leather in high temperature, humid environment, etc., which has a negative impact on the quality and storage stability of polyurethane synthetic leather. Adding additives such as flame retardants, light stabilizers, hydrolysis stabilizers, etc. into supercritical fluids causes bubble nucleation in a thermodynamically unstable state, and the additive microparticles can remain in the gas core. After rapid cooling, the bubbles are shaped, effectively preventing the additives from precipitating on the surface. Summary of the invention
[0005] In order to overcome the shortcomings of the above-mentioned prior art, the present invention provides a method for preparing high-property polyurethane synthetic leather assisted by supercritical CO2 foaming, and the synergistic effect of supercritical fluid is used to make the solvent-free A / B material mixing more uniform. The uniformly mixed homogeneous system is conducive to providing film forming and leveling, so that the prepared synthetic leather has a soft feel.
[0006] In order to achieve the above object, the present invention adopts the following technical solutions:
[0007] A method for preparing high-property polyurethane synthetic leather assisted by supercritical CO2 foaming method comprises the following steps:
[0008] Step (1), preparing polyurethane surface layer slurry: adding a certain proportion of solvent to water-based polyurethane surface layer resin, adjusting to a suitable viscosity range, adding leveling agent, defoaming agent, slip agent, halogen-free color paste, stirring evenly, filtering, and vacuum degassing to obtain the polyurethane surface layer slurry;
[0009] Step (2), preparing a high-solid polyurethane intermediate layer slurry: adding a certain proportion of solvent to the polyurethane intermediate layer resin, adjusting the viscosity to a suitable range, adding halogen-free color paste, stirring evenly, filtering, and vacuum degassing to obtain the high-solid polyurethane intermediate layer slurry;
[0010] Step (3), preparing a two-component polyurethane adhesive layer slurry: adding a solvent-free A component to an A material tank, adding fillers and catalysts, stirring inside to obtain an A material, adding a solvent-free B component to a B material tank, stirring inside to obtain a B material, and circulating the mixture until it enters a mixing head;
[0011] Step (4), adding the auxiliary agent into the autoclave, heating the autoclave to a temperature of 31.26° C., pumping CO2 into the autoclave, exhausting the internal air, controlling the pressure in the autoclave to 7.3 MPa, maintaining the temperature and pressure, and dissolving the auxiliary agent in the supercritical CO2 fluid;
[0012] Step (5), applying the polyurethane surface layer slurry on the surface of the release paper, heating and drying, to obtain the polyurethane surface layer;
[0013] Step (6), applying the high-solid polyurethane intermediate layer slurry on the polyurethane surface layer, heating and drying, to obtain a high-solid polyurethane intermediate layer;
[0014] Step (7), the material A and the material B are metered by the metering pump and then enter the mixing head from the material A tank and the material B tank for high-speed stirring and mixing. At the same time, the supercritical CO2 fluid that dissolves the additive is delivered to the head in a predetermined ratio, mixed evenly with the material A and the material B, applied to the high-solid polyurethane intermediate layer, and heated and dried to the required laminating dryness and wetness to obtain a two-component polyurethane adhesive layer;
[0015] Step (8), semi-dry laminating the two-component polyurethane adhesive layer to the base fabric, separating and rolling up after aging, so as to obtain synthetic leather.
[0016] In the above technical solution, in step (4), the auxiliary agent includes a flame retardant, a light stabilizer, and a hydrolysis stabilizer.
[0017] In the above technical scheme, in steps (1) and (2), the solvent is one of DMF, EA, and MEK.
[0018] In the above technical scheme, in step (1), the mass ratio of waterborne polyurethane surface layer resin, solvent, leveling agent, defoaming agent, slip agent and halogen-free color paste is 100:(0-70):(0.01-1):(0.01-1):(0.1-1):(1-10).
[0019] In the above technical solution, in step (2), the mass ratio of the polyurethane intermediate layer resin, the solvent, and the halogen-free color paste is 100:(20-50):(1-20).
[0020] In the above technical solution, in step (3), the mass ratio of solvent-free component A, solvent-free component B, filler and catalyst is 100:(50-120):(0-30):(0.01-1).
[0021] In the above technical solution, in step (1), the waterborne polyurethane surface layer resin is a polycarbonate type, aromatic polyurethane with a solid content of 30-40% and a 100% modulus of 100-200 kg / cm 2 .
[0022] In the above technical solution, in step (3), the solvent-free component A is a polyether polyol, and the solvent-free component B is an aromatic isocyanate.
[0023] In the above technical solution, in step (3), the filler is one or a mixture of two or more of matting powder, aluminum hydroxide, aluminum oxide, magnesium hydroxide, zinc borate, aluminum silicate, magnesium carbonate, glass microbeads, white carbon black, silicone resin powder, silicon dioxide, calcium carbonate or magnesium oxide.
[0024] The beneficial effects of the present invention are:
[0025] 1. The synergistic effect of supercritical fluid makes the solvent-free A / B material mixing more uniform. The uniformly mixed homogeneous system is conducive to providing film-forming leveling, thereby preparing synthetic leather with a soft feel.
[0026] 2. Add additives such as flame retardants, light stabilizers, hydrolysis stabilizers, etc. to the supercritical fluid, mix material A with material B and mix them evenly. When the die is sprayed out, the pressure drops to cause foaming. The additive microparticles can remain in the gas core, effectively avoiding problems such as the precipitation of additive particles on the surface. DETAILED DESCRIPTION
[0027] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. The present invention can be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that this disclosure will be thorough and complete, and the concept of the present invention will be fully conveyed to those skilled in the art, and the present invention will only be limited by the claims.
[0028] The present invention provides a method for preparing high-property polyurethane synthetic leather assisted by supercritical CO2 foaming method, wherein the synthetic leather comprises a surface layer, an intermediate layer, an adhesive layer and a base fabric layer from top to bottom, and the specific preparation method is as follows:
[0029] Step (1), preparing polyurethane surface layer slurry: adding a certain proportion of solvent to water-based polyurethane surface layer resin, adjusting to a suitable viscosity range, adding leveling agent, defoaming agent, slip agent, halogen-free color paste, stirring evenly and filtering, vacuum degassing, and obtaining polyurethane surface layer slurry.
[0030] Specifically, the waterborne polyurethane surface resin is a polycarbonate, aromatic polyurethane with a solid content of 30-40% and a 100% modulus of 100-200 kg / cm 2 .
[0031] The solvent is one of DMF, EA and MEK.
[0032] The leveling agent is preferably a silicone leveling agent, such as BYK-L-9565.
[0033] The defoamer is preferably a silicone-polyether copolymer defoamer, such as JN3-095.
[0034] The slip agent is preferably a silicone feel aid, such as JN3-018.
[0035] The halogen-free colorant is preferably SEIKABEAM BC series colorant.
[0036] The mass ratio of waterborne polyurethane surface layer resin, solvent, leveling agent, defoaming agent, slip agent and halogen-free color paste is 100:(0-70):(0.01-1):(0.01-1):(0.1-1):(1-10).
[0037] Step (2), preparing high-solid polyurethane intermediate layer slurry: adding a certain proportion of solvent to the polyurethane intermediate layer resin, adjusting to a suitable viscosity range, adding halogen-free color paste, stirring evenly, filtering, and vacuum degassing to obtain high-solid polyurethane intermediate layer slurry.
[0038] Specifically, the polyurethane intermediate layer resin is a polyester-type, aromatic high-solid polyurethane with a solid content of 50-90%.
[0039] The solvent is one of DMF, EA and MEK.
[0040] The halogen-free colorant is preferably SEIKABEAM BC series colorant.
[0041] The mass ratio of the polyurethane intermediate layer resin, the solvent and the halogen-free color paste is 100:(20-50):(1-20).
[0042] Step (3), preparing a two-component polyurethane adhesive layer slurry: adding the solvent-free A component to the A material tank, adding fillers and catalysts and stirring inside to obtain A material, adding the solvent-free B component to the B material tank and stirring to obtain B material, and circulating the slurry until it enters the mixing head.
[0043] Specifically, the mass ratio of the solvent-free A component, the solvent-free B component, the filler, and the catalyst is 100:(50-120):(0-30):(0.01-1).
[0044] The solvent-free A component is polyether polyol, and the solvent-free B component is aromatic isocyanate, such as Hexin Technology HX-NS-2003A / B, HX-NS-6006A / B, etc.
[0045] The filler is one or a mixture of two or more of matting powder, aluminum hydroxide, aluminum oxide, magnesium hydroxide, zinc borate, aluminum silicate, magnesium carbonate, glass microspheres, white carbon black, silicone resin micropowder, silicon dioxide, calcium carbonate or magnesium oxide. The filler particle content affects the cell size and cell density. The filler should be evenly dispersed without unevenness such as clumping.
[0046] The catalyst is preferably a metal or amine catalyst, such as HX-304, HX-513, etc. produced by Hexin Technology.
[0047] Step (4), adding the auxiliary agent into the high-pressure reactor, heating the reactor to a temperature of 31.26°C, pumping CO2 into the high-pressure reactor, exhausting the internal air, controlling the pressure in the reactor to 7.3 MPa, maintaining the temperature and pressure for a period of time, so that the auxiliary agent is dissolved in the supercritical CO2 fluid.
[0048] Specifically, the additives include flame retardants, light stabilizers, and hydrolysis stabilizers. The additives are dissolved in supercritical CO2, and the additive particles remain in the gas core during the foaming process, which is stable and will not precipitate. In addition, the process of fluid flow rate, pressure, etc. can adjust the open and closed cells of the foam, and the synthetic leather feels softer.
[0049] Step (5), applying the polyurethane surface layer slurry to the surface of the release paper, heating and drying, to obtain the polyurethane surface layer.
[0050] Step (6), applying the high-solid polyurethane intermediate layer slurry on the polyurethane surface layer, heating and drying, to obtain the high-solid polyurethane intermediate layer.
[0051] Step (7), after being metered by a metering pump, material A and material B enter the mixing head from the material tank A and the material tank B for high-speed stirring and mixing. At the same time, the supercritical CO2 fluid that dissolves the auxiliary agent is delivered to the head in a predetermined ratio, mixed evenly with material A and material B, and applied to the high-solid polyurethane intermediate layer. It is heated and baked to the required bonding wetness to obtain a two-component polyurethane adhesive layer.
[0052] Step (8), semi-dry laminating the two-component polyurethane adhesive layer to the base fabric, separating and rolling up after aging, and obtaining the synthetic leather.
[0053] Among them, resins with different solid contents are selected according to the grammage of the base fabric, and the base fabric can be non-woven fabric, woven fabric, knitted fabric, microfiber, etc.
[0054] After the synthetic leather was prepared by the preparation method of the present invention, performance tests were performed using the national standard and industry standard for synthetic leather. The test results are shown in Table 1.
[0055]
[0056] In addition, according to the effects of different additives dissolved in supercritical CO2, such as flame retardants, light stabilizers, and hydrolysis stabilizers, tests were conducted separately. The test results are shown in Table 2 below.
[0057] Table 2 Experimental test results
[0058]
[0059] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.
Claims
1. A method for preparing high-property polyurethane synthetic leather assisted by supercritical CO2 foaming, characterized in that: The following steps are involved: Step (1), preparing polyurethane surface layer slurry: adding a certain proportion of solvent to water-based polyurethane surface layer resin, adjusting to a suitable viscosity range, adding leveling agent, defoaming agent, slip agent, halogen-free color paste, stirring evenly, filtering, and vacuum degassing to obtain the polyurethane surface layer slurry; Step (2), preparing a high-solid polyurethane intermediate layer slurry: adding a certain proportion of solvent to the polyurethane intermediate layer resin, adjusting the viscosity to a suitable range, adding halogen-free color paste, stirring evenly, filtering, and vacuum degassing to obtain the high-solid polyurethane intermediate layer slurry; Step (3), preparing a two-component polyurethane adhesive layer slurry: adding a solvent-free A component to an A material tank, adding fillers and catalysts, stirring inside to obtain an A material, adding a solvent-free B component to a B material tank, stirring inside to obtain a B material, and circulating the mixture until it enters a mixing head; Step (4), adding the auxiliary agent into the autoclave, heating the autoclave to a temperature of 31.26° C., pumping CO2 into the autoclave, exhausting the internal air, controlling the pressure in the autoclave to 7.3 MPa, maintaining the temperature and pressure, and dissolving the auxiliary agent in the supercritical CO2 fluid; Step (5), applying the polyurethane surface layer slurry on the surface of the release paper, heating and drying, to obtain the polyurethane surface layer; Step (6), applying the high-solid polyurethane intermediate layer slurry on the polyurethane surface layer, heating and drying, to obtain a high-solid polyurethane intermediate layer; Step (7), the material A and the material B are metered by the metering pump and then enter the mixing head from the material A tank and the material B tank for high-speed stirring and mixing. At the same time, the supercritical CO2 fluid that dissolves the additive is delivered to the head in a predetermined ratio, mixed evenly with the material A and the material B, applied to the high-solid polyurethane intermediate layer, and heated and dried to the required laminating dryness and wetness to obtain a two-component polyurethane adhesive layer; Step (8), semi-dry laminating the two-component polyurethane adhesive layer to the base fabric, separating and rolling up after aging, so as to obtain synthetic leather.
2. The preparation method according to claim 1, characterized in that: In step (4), the auxiliary agents include flame retardants, light stabilizers, and hydrolysis stabilizers.
3. The preparation method according to claim 1, characterized in that: In steps (1) and (2), the solvent is one of DMF, EA, and MEK.
4. The preparation method according to claim 1, characterized in that: In step (1), the mass ratio of waterborne polyurethane surface layer resin, solvent, leveling agent, defoaming agent, slip agent and halogen-free color paste is 100:(0-70):(0.01-1):(0.01-1):(0.1-1):(1-10).
5. The preparation method according to claim 1, characterized in that: In step (2), the mass ratio of the polyurethane intermediate layer resin, the solvent, and the halogen-free color paste is 100:(20-50):(1-20).
6. The preparation method according to claim 1, characterized in that: In step (3), the mass ratio of solvent-free component A, solvent-free component B, filler and catalyst is 100:(50-120):(0-30):(0.01-1).
7. The preparation method according to claim 1, characterized in that: In step (1), the waterborne polyurethane surface layer resin is a polycarbonate type, aromatic polyurethane with a solid content of 30-40% and a 100% modulus of 100-200 kg / cm 2 .
8. The preparation method according to claim 1, characterized in that: In step (3), the solvent-free A component is a polyether polyol, and the solvent-free B component is an aromatic isocyanate.
9. The preparation method according to claim 1, characterized in that: In step (3), the filler is one or a mixture of two or more of matting powder, aluminum hydroxide, aluminum oxide, magnesium hydroxide, zinc borate, aluminum silicate, magnesium carbonate, glass microbeads, white carbon black, silicone resin powder, silicon dioxide, calcium carbonate or magnesium oxide.