Preparation method of microfiber leather

Abstract

The present application relates to the field of superfine fiber synthetic leather, and provides a preparation method of superfine fiber leather imitation, which solves the defects of the existing technology, such as environmental protection, rough hand feeling of the prepared product, and the method comprises the following preparation steps: (1) preparing a base cloth layer; (2) preparing a two-component water-based functional slurry; (3) first coating; (4) second coating; (5) foaming and preliminary gelation treatment; (6) coagulation treatment; (7) hot water dissolution treatment; (8) washing and low-temperature setting; (9) drying and finishing.

Description

Technical Field

[0001] This invention relates to the field of microfiber synthetic leather, and more particularly to a method for preparing microfiber-like leather. Background Technology

[0002] Microfiber materials, with their excellent physical properties and texture and appearance similar to natural leather, are widely used in many fields, such as footwear, bags, automotive interiors, and furniture décor. However, the complex production process and high cost of microfiber materials limit their wider adoption. To meet the market demand for low-cost, high-performance microfiber-like materials, imitation microfiber materials have emerged.

[0003] Currently, existing methods for manufacturing imitation microfiber have many shortcomings. On the one hand, some imitation microfiber products still lag significantly behind genuine microfiber in terms of physical properties such as feel, softness, and abrasion resistance, making it difficult to meet the requirements of high-end applications. For example, some imitation microfiber materials feel stiff and lack the delicate, soft, and elastic touch of genuine microfiber, making them prone to wear and tear and breakage during use. On the other hand, existing manufacturing processes may suffer from significant environmental pollution and low production efficiency. Traditional processes often use large amounts of organic solvents, which not only threaten the health of operators but also pollute the environment. Furthermore, the lengthy process leads to long production cycles, failing to meet the rapidly growing market demand.

[0004] Therefore, developing a new method for manufacturing microfiber-like products to improve their quality while reducing production costs, increasing production efficiency, and reducing environmental pollution is of great practical significance. Summary of the Invention

[0005] Therefore, in view of the above problems, the present invention provides a method for preparing imitation microfiber leather, which solves the defects of the existing imitation microfiber leather preparation process being not environmentally friendly and the resulting product having a rough feel.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a method for preparing imitation microfiber leather, comprising the following preparation steps: (1) Preparation of the base fabric layer; (2) Prepare a two-component water-based functional slurry, wherein the two-component water-based functional slurry includes slurry A and slurry B. Slurry A is composed of the following raw materials in parts by weight: 100 parts of water-based anionic polyurethane dispersion, 15-25 parts of modified phase change microcapsules, 3-5 parts of nano titanium dioxide dispersion, 2-3 parts of azodicarbonamide, 0.3-0.8 parts of nonionic surfactant, 0.1-0.5 parts of leveling agent, and 5-20 parts of deionized water. The viscosity of slurry A is 3000-5000 cps. Slurry B is composed of the following raw materials in parts by weight: 100 parts of water-based aliphatic polyurethane, 5-8 parts of nano silica, 1-2 parts of silicone emulsion, and 0.5-2 parts of nonionic thickener. The viscosity of slurry B is 8000-12000 cps. (3) First coating: The A slurry is coated on the back of the base fabric layer by an impregnation extrusion roller or a doctor blade. By controlling the roller gap pressure, 70-80% of the slurry penetrates into the base fabric and 20-30% remains on the bottom surface of the base fabric. Then it enters the pre-coagulation zone (60-70℃ hot air, 1-2 minutes) to make the surface of the slurry initially gel. (4) Second coating: On the front side of the base fabric layer, the B slurry is applied by a doctor blade to form a uniform and independent coating on the front side of the base fabric. (5) Foaming and preliminary gelation treatment: The material coated in step (4) is introduced into the first zone and treated in a hot and humid environment with a temperature of 70-85℃ and a relative humidity of ≥85% for 2-4 minutes to decompose and foam the foaming agent in slurry A and to preliminarily gel the slurry system. (6) Coagulation treatment: The material after step (5) is introduced into the coagulation bath of the second zone. The coagulation bath is an ammonium sulfate aqueous solution with a concentration of 10-20%. It is treated at 30-40℃ for 3-5 minutes to cause phase separation and coagulation of polyurethane to form a porous elastic skeleton. (7) Hot water leaching treatment: The material after step (6) is introduced into the hot water bath in the third zone. The hot water bath is flowing deionized water. It is treated at 60-70℃ for 4-8 minutes to dissolve the water-soluble island fiber components in the base fabric. (8) Washing and low temperature setting: The material after step (7) is introduced into the cold water bath of the fourth zone and treated in flowing deionized water at 5-15℃ for 1-3 minutes for final setting and cleaning; (9) Drying and finishing: The material processed in step (8) is dried and embossed to obtain imitation microfiber leather.

[0007] Furthermore, the preparation process of the base fabric layer is as follows: polyester / polyvinyl alcohol island fiber and polyurethane elastic fiber are mixed at a mass ratio of 90-95:5-10, and then formed into a web by airflow and reinforced by needle punching to produce a product with a basis weight of 100-150 g / m².2 The nonwoven fabric base layer.

[0008] Furthermore, after needle-punching reinforcement, the base fabric layer is subjected to low-temperature hot rolling shaping treatment, wherein the temperature of the low-temperature hot rolling is 100-110℃.

[0009] Further: The modified phase change microcapsules in step (2) are composed of n-octadecane, polyurethane prepolymer and melamine-formaldehyde resin prepolymer in a weight ratio of 50:5:150, wherein n-octadecane is the core material and melamine-formaldehyde resin prepolymer and polyurethane prepolymer are the wall materials.

[0010] Furthermore, a waste gas condensation dehumidification and preheating recovery step is added between step (5) and step (9). The high temperature and high humidity waste gas generated in step (5) is discharged into a low temperature condenser for condensation treatment. Then, the latent heat released by the gas condensation is recovered and the latent heat is used to preheat the fresh air entering the drying step (9).

[0011] Furthermore, the B slurry also contains 0.5-2 parts by weight of thermally expanded microspheres, which expand under heat during the drying process in step (9) and form micro-random textures on the surface of the material.

[0012] Furthermore, the A slurry also contains 2-5 parts by weight of composite purification material.

[0013] Furthermore, the composite purification material is a composite powder formed by supporting nano-titanium dioxide on porous zeolite.

[0014] Furthermore, the composite purification material is a composite powder formed by supporting nano-titanium dioxide on a porous zeolite imidazole ester framework material.

[0015] By adopting the aforementioned technical solution, the beneficial effects of the present invention are as follows: 1. This application uses a sea island fiber base fabric layer combined with specific A slurry and B slurry. The A slurry is distributed and penetrated on the back of the base fabric layer, and the B slurry is coated on the front of the base fabric layer, forming a microfiber-like leather with a dense and wear-resistant surface, a porous and elastic middle layer, and a strong bond between the bottom layer and the fiber. The product has a full and soft feel.

[0016] 2. A slurry integrates multiple functions such as foaming, phase change temperature regulation, and photocatalysis. During the molding process, it simultaneously constructs a porous skeleton and fixes functional materials, realizing the integration of multiple functions such as lightweight, heat insulation, and intelligent temperature regulation, breaking through the limitations of the single function of traditional coatings.

[0017] 3. The preparation process of this application adopts an aqueous system, avoiding the use of toxic solvents such as DMF, and the PVA component is dissolved by hot water, making the process clean and environmentally friendly.

[0018] 4. The base fabric is made of polyester / polyvinyl alcohol island fiber, which provides a basis for the subsequent hot water dissolution of polyvinyl alcohol and the in-situ formation of an ultra-fine fiber network structure. The infiltration of polyurethane elastic fibers gives the base fabric better elasticity, so that the final product has better tensile recovery and flexibility, overcoming the shortcomings of traditional non-woven base fabric leather that is too hard and easily deformed.

[0019] 5. Furthermore, thermally expandable microspheres are added to slurry B. By utilizing their thermal expansion characteristics under high drying temperature, micro-stress is generated inside the skin layer of the material surface, thereby forming random and uneven micro-texture.

[0020] 6. Furthermore, by adding composite purification materials to slurry A, the resulting imitation microfiber leather can eliminate odors and volatile organic compounds in the environment, making it suitable for use in automotive interior leather. Detailed Implementation

[0021] Example 1

[0022] A method for preparing imitation microfiber leather includes the following preparation steps: (1) Preparation of the base fabric layer: Polyester / polyvinyl alcohol island fiber and polyurethane elastic fiber are mixed at a mass ratio of 90:10, and then formed into a web by air-flow and needle-punching to produce a fabric with a basis weight of 100g / m 2 The nonwoven fabric base layer; (2) Prepare a two-component water-based functional slurry, wherein the two-component water-based functional slurry includes slurry A and slurry B. Slurry A is composed of the following raw materials in parts by weight: 100 parts of water-based anionic polyurethane dispersion, 15 parts of modified phase change microcapsules, 3 parts of nano titanium dioxide dispersion, 2 parts of azodicarbonamide, 0.3 parts of nonionic surfactant, 0.1 parts of leveling agent, and 5 parts of deionized water. The viscosity of slurry A is 3000 cps. Slurry B is composed of the following raw materials in parts by weight: 100 parts of water-based aliphatic polyurethane, 5 parts of nano silica, 1 part of silicone emulsion, and 0.5 parts of nonionic thickener. The viscosity of slurry B is 8000 cps. The modified phase change microcapsules are composed of n-octadecane, polyurethane prepolymer, and melamine-formaldehyde resin prepolymer in a weight ratio of 50:5:150, wherein n-octadecane is the core material, and melamine-formaldehyde resin prepolymer and polyurethane prepolymer are the wall materials. (3) First coating: The A slurry is coated on the back of the base fabric layer by an impregnation extrusion roller or a doctor blade. By controlling the roller gap pressure, 70% of the slurry penetrates into the base fabric and 30% remains on the bottom surface of the base fabric. Then it enters the pre-coagulation zone (60°C hot air, 1 minute) to make the surface of the slurry initially gel. (4) Second coating: On the front side of the base fabric layer, the B slurry is applied by a doctor blade to form a uniform and independent coating on the front side of the base fabric. (5) Foaming and preliminary gelation treatment: The material coated in step (4) is introduced into the first zone and treated in a hot and humid air environment with a temperature of 70°C and a relative humidity of ≥85% for 2 minutes to decompose and foam the foaming agent in slurry A and to preliminarily gel the slurry system. (6) Coagulation treatment: The material after step (5) is introduced into the coagulation bath of the second zone. The coagulation bath is an aqueous solution of ammonium sulfate with a concentration of 10%. It is treated at 30°C for 3 minutes to cause phase separation and coagulation of polyurethane to form a porous elastic skeleton. (7) Hot water leaching treatment: The material after step (6) is introduced into the hot water bath in the third zone. The hot water bath is flowing deionized water. It is treated at 60°C for 4 minutes to dissolve the water-soluble island fiber components in the base fabric. (8) Washing and low temperature setting: The material after step (7) is introduced into the cold water bath of the fourth zone and treated in flowing deionized water at 5°C for 1 min for final setting and cleaning; (9) Drying and finishing: The material processed in step (8) is dried and embossed to obtain imitation microfiber leather.

[0023] Example 2 A method for preparing imitation microfiber leather includes the following preparation steps: (1) Preparation of base fabric layer: Polyester / polyvinyl alcohol island fiber and polyurethane elastic fiber are mixed at a mass ratio of 92:8, and then subjected to air-flow web formation, needle punching reinforcement, and low-temperature hot rolling and shaping treatment. The low-temperature hot rolling temperature is 105℃, and the resulting fabric has a basis weight of 125g / m 2 The nonwoven fabric base layer; (2) Prepare a two-component water-based functional slurry, wherein the two-component water-based functional slurry includes slurry A and slurry B. Slurry A is composed of the following raw materials in parts by weight: 100 parts of water-based anionic polyurethane dispersion, 20 parts of modified phase change microcapsules, 4 parts of nano titanium dioxide dispersion, 2.5 parts of azodicarbonamide, 0.5 parts of nonionic surfactant, 0.3 parts of leveling agent, 5 parts of composite purification material, and 15 parts of deionized water. The viscosity of slurry A is 4000 cps. The composite purification material is a composite powder formed by nano titanium dioxide loaded on porous zeolite. The B slurry is composed of the following raw materials in parts by weight: 100 parts of water-based aliphatic polyurethane, 7 parts of nano silica, 1.5 parts of organosilicon emulsion, 0.1 parts of nonionic thickener, and 1 part of thermally expandable microspheres. The viscosity of the B slurry is 10,000 cps. The modified phase change microcapsules are composed of n-octadecane, polyurethane prepolymer, and melamine-formaldehyde resin prepolymer in a weight ratio of 50:5:150, wherein n-octadecane is the core material, and melamine-formaldehyde resin prepolymer and polyurethane prepolymer are the wall materials. (3) First coating: The A slurry is coated on the back of the base fabric layer by an impregnation extrusion roller or a doctor blade. By controlling the roller gap pressure, 75% of the slurry penetrates into the base fabric and 25% remains on the bottom surface of the base fabric. Then, it enters the pre-coagulation zone (65°C hot air, 1.5 minutes) to allow the surface of the slurry to initially gel. (4) Second coating: On the front side of the base fabric layer, the B slurry is applied by a doctor blade to form a uniform and independent coating on the front side of the base fabric. (5) Foaming and preliminary gelation treatment: The material coated in step (4) is introduced into the first zone and treated in a hot and humid air environment with a temperature of 77°C and a relative humidity of ≥85% for 3 minutes to decompose and foam the foaming agent in slurry A and to preliminarily gel the slurry system. (6) Coagulation treatment: The material after step (5) is introduced into the coagulation bath of the second zone. The coagulation bath is an aqueous solution of ammonium sulfate with a concentration of 15%. It is treated at 35°C for 4 minutes to cause the polyurethane to undergo phase separation and coagulation, forming a porous elastic skeleton. (7) Hot water leaching treatment: The material after step (6) is introduced into the hot water bath in the third zone. The hot water bath is flowing deionized water. It is treated at 65°C for 6 minutes to dissolve the water-soluble island fiber components in the base fabric. (8) Washing and low temperature setting: The material after step (7) is introduced into the cold water bath of the fourth zone and treated in flowing deionized water at 10°C for 2 minutes for final setting and cleaning; (9) Drying and finishing: The material processed in step (8) is dried and embossed to obtain imitation microfiber leather. The thermally expanding microspheres are heated and expanded during the drying process in this step, and micro-random textures are formed on the surface of the material.

[0024] Example 3 A method for preparing imitation microfiber leather includes the following preparation steps: (1) Preparation of the base fabric layer: Polyester / polyvinyl alcohol island fiber and polyurethane elastic fiber are mixed at a mass ratio of 95:5, and then subjected to air-flow web formation, needle punching reinforcement, and low-temperature hot rolling and shaping treatment. The low-temperature hot rolling temperature is 110℃, and the resulting fabric has a basis weight of 150g / m². 2 The nonwoven fabric base layer; (2) Prepare a two-component water-based functional slurry, wherein the two-component water-based functional slurry includes slurry A and slurry B. Slurry A is composed of the following raw materials in parts by weight: 100 parts of water-based anionic polyurethane dispersion, 25 parts of modified phase change microcapsules, 5 parts of nano titanium dioxide dispersion, 3 parts of azodicarbonamide, 0.8 parts of nonionic surfactant, 0.5 parts of leveling agent, 5 parts of composite purification material, and 20 parts of deionized water. The viscosity of slurry A is 5000 cps. Slurry B is composed of the following raw materials in parts by weight: 100 parts of water-based aliphatic polyurethane, 8 parts of nano silica, 2 parts of organosilicon emulsion, 2 parts of nonionic thickener, and 2 parts of thermally expandable microspheres. The viscosity of slurry B is 12000 cps. The modified phase change microcapsules are composed of n-octadecane, polyurethane prepolymer, and melamine-formaldehyde resin prepolymer in a weight ratio of 50:5:150, wherein n-octadecane is the core material, and melamine-formaldehyde resin prepolymer and polyurethane prepolymer are the wall materials. The composite purification material is a composite powder formed by nano-titanium dioxide loaded on a porous zeolite imidazole ester framework material. (3) First coating: The A slurry is coated on the back of the base fabric layer by an impregnation extrusion roller or a doctor blade. By controlling the roller gap pressure, 80% of the slurry penetrates into the base fabric and 20% remains on the bottom surface of the base fabric. Then it enters the pre-coagulation zone (70°C hot air, 2 minutes) to allow the surface of the slurry to initially gel. (4) Second coating: On the front side of the base fabric layer, the B slurry is applied by a doctor blade to form a uniform and independent coating on the front side of the base fabric. (5) Foaming and preliminary gelation treatment: The material coated in step (4) is introduced into the first zone and treated in a hot and humid air environment with a temperature of 85℃ and a relative humidity of ≥85% for 4 minutes to decompose and foam the foaming agent in slurry A and to preliminarily gel the slurry system. (6) Coagulation treatment: The material after step (5) is introduced into the coagulation bath of the second zone. The coagulation bath is an aqueous solution of ammonium sulfate with a concentration of 20%. It is treated at 40°C for 5 minutes to cause phase separation and coagulation of polyurethane to form a porous elastic skeleton. (7) Hot water leaching treatment: The material after step (6) is introduced into the hot water bath in the third zone. The hot water bath is flowing deionized water. It is treated at 70°C for 8 minutes to dissolve the water-soluble island fiber components in the base fabric. (8) Washing and low temperature setting: The material after step (7) is introduced into the cold water bath of the fourth zone and treated in flowing deionized water at 15°C for 3 minutes for final setting and cleaning; (9) Drying and finishing: The material treated in step (8) is dried and embossed to obtain imitation microfiber leather. The thermally expanding microspheres expand under heat during the drying process in this step, causing micro-random textures to form on the surface of the material; A waste gas condensation dehumidification and preheating recovery step is added between step (5) and step (9). The high temperature and high humidity waste gas generated in step (5) is discharged into a low temperature condenser for condensation treatment. Then, the latent heat released by the gas condensation is recovered and the latent heat is used to preheat the fresh air entering the drying step (9).

[0025] The performance of the imitation microfiber leather obtained in Examples 1 to 3 of this application was tested, and the results are shown in the table below:

[0026] From Examples 1 to 3, while maintaining excellent basic performance, the products have achieved significant improvements in intelligent temperature control (significantly improved phase change enthalpy), air purification (highly efficient VOC removal rate), surface texture (random hydrophobic texture), and production process energy efficiency.

[0027] Although the invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the invention without departing from the spirit and scope of the invention as defined in the appended claims, all of which shall be within the scope of protection of the invention.

Claims

1. A method for preparing a microfiber-like leather, characterized in that, The preparation steps include the following: (1) Preparation of the base fabric layer; (2) Prepare a two-component water-based functional slurry, wherein the two-component water-based functional slurry includes slurry A and slurry B. Slurry A is composed of the following raw materials in parts by weight: 100 parts of water-based anionic polyurethane dispersion, 15-25 parts of modified phase change microcapsules, 3-5 parts of nano titanium dioxide dispersion, 2-3 parts of azodicarbonamide, 0.3-0.8 parts of nonionic surfactant, 0.1-0.5 parts of leveling agent, and 5-20 parts of deionized water. The viscosity of slurry A is 3000-5000 cps. Slurry B is composed of the following raw materials in parts by weight: 100 parts of water-based aliphatic polyurethane, 5-8 parts of nano silica, 1-2 parts of silicone emulsion, and 0.5-2 parts of nonionic thickener. The viscosity of slurry B is 8000-12000 cps. (3) First coating: The A slurry is coated on the back of the base fabric layer by an impregnation extrusion roller or a doctor blade. By controlling the roller gap pressure, 70-80% of the slurry penetrates into the base fabric and 20-30% remains on the bottom surface of the base fabric. Then it enters the pre-coagulation zone to allow the surface of the slurry to initially gel. (4) Second coating: On the front side of the base fabric layer, the B slurry is applied by a doctor blade to form a uniform and independent coating on the front side of the base fabric. (5) Foaming and preliminary gelation treatment: The material coated in step (4) is introduced into the first zone and treated in a hot and humid environment with a temperature of 70-85℃ and a relative humidity of ≥85% for 2-4 minutes to decompose and foam the foaming agent in slurry A and to preliminarily gel the slurry system. (6) Coagulation treatment: The material after step (5) is introduced into the coagulation bath of the second zone. The coagulation bath is an ammonium sulfate aqueous solution with a concentration of 10-20%. It is treated at 30-40℃ for 3-5 minutes to cause phase separation and coagulation of polyurethane to form a porous elastic skeleton. (7) Hot water leaching treatment: The material after step (6) is introduced into the hot water bath in the third zone. The hot water bath is flowing deionized water. It is treated at 60-70℃ for 4-8 minutes to dissolve the water-soluble island fiber components in the base fabric. (8) Washing and low temperature setting: The material after step (7) is introduced into the cold water bath of the fourth zone and treated in flowing deionized water at 5-15℃ for 1-3 minutes for final setting and cleaning; (9) Drying and finishing: The material processed in step (8) is dried and embossed to obtain imitation microfiber leather.

2. The method for preparing a microfiber-like leather according to claim 1, characterized in that, The preparation process of the base fabric layer is as follows: polyester / polyvinyl alcohol island fiber and polyurethane elastic fiber are mixed at a mass ratio of 90-95:5-10, and then formed into a web by air-flow and needle-punched reinforcement to produce a weight of 100-150 g / m². 2 The nonwoven fabric base layer.

3. The method for preparing a microfiber-like leather according to claim 2, characterized in that: After needle-punching reinforcement, the base fabric layer is subjected to low-temperature hot rolling shaping treatment, and the temperature of the low-temperature hot rolling is 100-110℃.

4. The method for preparing a microfiber-like leather according to claim 1, characterized in that: The modified phase change microcapsules described in step (2) are composed of n-octadecane, polyurethane prepolymer, and melamine-formaldehyde resin prepolymer in a weight ratio of 50:5:150, wherein n-octadecane is the core material, and melamine-formaldehyde resin prepolymer and polyurethane prepolymer are the wall materials.

5. The method for preparing a microfiber-like leather according to claim 1, characterized in that: A waste gas condensation dehumidification and preheating recovery step is added between step (5) and step (9). The high temperature and high humidity waste gas generated in step (5) is discharged into a low temperature condenser for condensation treatment. Then, the latent heat released by the gas condensation is recovered and the latent heat is used to preheat the fresh air entering the drying step (9).

6. The method for preparing a microfiber-like leather according to claim 1, characterized in that: The B slurry also contains 0.5-2 parts by weight of thermally expandable microspheres, which expand under heat during the drying process in step (9) and form micro-random textures on the surface of the material.

7. The method for preparing a microfiber-like leather according to claim 1, characterized in that: The A slurry also contains 2-5 parts by weight of composite purification material.

8. The method for preparing a microfiber-like leather according to claim 7, characterized in that: The composite purification material is a composite powder formed by nano-titanium dioxide loaded on porous zeolite.

9. The method for preparing a microfiber-like leather according to claim 7, characterized in that: The composite purification material is a composite powder formed by loading nano-titanium dioxide onto a porous zeolite imidazole ester framework material.

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