Ultra-fine leather with good air permeability and production process

Abstract

The present invention relates to a microfiber leather with good air permeability and a production process, belonging to the technical field of synthetic leather. The microfiber leather is composited by a microfiber base cloth and a polyurethane slurry, wherein the polyurethane slurry comprises, by weight, 40-50 parts of modified polyurethane, 2.8-3.5 parts of light calcium powder, 0.25-0.35 parts of defoamer, 0.05-0.08 parts of light stabilizer and 50-60 parts of ethyl acetate; the modified polyurethane is reacted by diallylamine and trimethoxysilyl chloride to form a silicon nitrogen compound, i.e., an intermediate, and then mercaptoethanol is added to the double bond in the intermediate by clicking to introduce a terminal hydroxyl group, i.e., a modified monomer is obtained, which is copolymerized with polypropylene glycol and isophorone diisocyanate, and is introduced into a polyurethane macromolecular chain by block, and interacts with the light calcium powder to form uniform microscopic gaps, greatly increasing the air permeability of the leather.

Description

Technical Field

[0001] The invention belongs to the technical field of synthetic leather, and in particular relates to a microfiber leather with good air permeability and a production process. Background Art

[0002] Ultrafine leather, also known as ultrafine fiber leather or microfiber leather, is a high-performance artificial leather material. It is made of ultrafine fibers through a special non-woven process and has many properties similar to natural leather. It is superior to natural leather in terms of mechanical strength, chemical corrosion resistance, biological resistance, quality uniformity, and adaptability to automated cutting and processing. At the same time, it has the advantages of high strength, light weight, and good shape retention over natural leather. It is an ideal substitute for natural leather and can be widely used in industrial, civil, military and other fields.

[0003] The production process of microfiber leather is to impregnate polyurethane emulsion into the gaps of the base fabric and use the adhesion structure of polyurethane to obtain a texture similar to natural leather. However, traditional polyurethane resins are prone to closure of the gaps constructed by microfibers after impregnation, resulting in insufficient air permeability of the microfiber leather, which seriously affects the comfort of the microfiber leather. Summary of the invention

[0004] In order to solve the technical problems mentioned in the background technology, the purpose of the present invention is to provide a microfiber leather with good air permeability and a production process.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A microfiber leather with good air permeability is composited by a microfiber base cloth and polyurethane slurry, wherein the polyurethane slurry comprises, by weight, 40-50 parts of modified polyurethane, 2.8-3.5 parts of light calcium powder, 0.25-0.35 parts of defoaming agent, 0.05-0.08 parts of light stabilizer and 50-60 parts of ethyl acetate.

[0007] The modified polyurethane is prepared by the following method:

[0008] Step A1: diallylamine, triethylamine and anhydrous tetrahydrofuran are mixed, dry nitrogen is introduced for protection, trimethoxysilyl chloride is added and mixed, the temperature is raised to 55-65° C., stirring is applied at 120-180 rpm, the reaction is carried out for 3-4 hours, and then tetrahydrofuran is removed by rotary evaporation to obtain an intermediate;

[0009] Furthermore, the dosage ratio of diallylamine, trimethoxysilyl chloride, triethylamine and anhydrous tetrahydrofuran is 0.1 mol: 0.1 mol: 6-10 mL: 20-30 mL. Under the promotion of triethylamine, diallylamine and trimethoxysilyl chloride react to form a silicon nitrogen compound.

[0010] Step A2: The intermediate, mercaptoethanol, dimethylphenylphosphine and acetone were mixed, nitrogen was introduced for protection, and stirring was performed at 30-50 rpm and 150-200 W / m at room temperature. 2 UV irradiation, reaction for 6-8h, then evaporation of acetone under reduced pressure to obtain a modified monomer;

[0011] Furthermore, the usage ratio of the intermediate, mercaptoethanol, dimethylphenylphosphine and acetone is 0.1 mol: 0.2 mol: 20-30 mg: 60-80 mL. Under the initiation of dimethylphenylphosphine and ultraviolet radiation, mercaptoethanol clicks and adds to the double bond in the intermediate to introduce terminal hydroxyl modification.

[0012] Step A3: isophorone diisocyanate and polypropylene glycol are mixed and charged as substrates, dibutyltin dilaurate is added, the temperature is raised to 80-90° C., stirring is applied at 40-60 rpm, the reaction is carried out for 1.5-2 hours, and then the modified monomer is added to continue the reaction for 2-3 hours, and then methanol is added, mixed and the temperature is lowered to below 50° C. to obtain a modified polyurethane;

[0013] Further, the molar ratio of isocyanate group to hydroxyl group of isophorone diisocyanate and polypropylene glycol is 1:0.68-0.85, the amount of modified monomer is 12-18wt% of the substrate, the amount of dibutyltin dilaurate is 1-1.5‰ of the substrate, isophorone diisocyanate and polypropylene glycol are prepolymerized, and then the modified blocks are copolymerized to form a block copolymer modified polyurethane;

[0014] Furthermore, the number average molecular weight of the polypropylene glycol is 2000-3000.

[0015] Furthermore, the fineness of the light calcium powder is not less than 800 mesh.

[0016] A production process of microfiber leather with good air permeability, comprising the following steps:

[0017] Step S1: premixing light calcium powder, defoaming agent, light stabilizer and ethyl acetate, and then adding modified polyurethane and mixing to obtain polyurethane slurry;

[0018] Step S2: repeatedly impregnating the microfiber base fabric in the polyurethane slurry and drying the microfiber base fabric, and controlling the dry weight increment to be 15±0.5wt% to obtain a composite leather;

[0019] Step S3: The composite leather is immersed and rolled twice in an alkali solution, then washed with water until the washing liquid is neutral, and dried to obtain a microfiber leather with good air permeability.

[0020] Furthermore, the alkali solution is a 10% sodium hydroxide aqueous solution, and the alkali solution temperature is 80°C.

[0021] Beneficial effects of the present invention:

[0022] The invention discloses a modified polyurethane, which is applied in the imitation cortex layer slurry of microfiber leather as a matrix to give the leather good mechanical properties and excellent air permeability. The modified polyurethane is prepared by reacting diallylamine and trimethoxychlorosilane to form a silicon nitrogen compound, i.e. an intermediate, and then a terminal hydroxyl group is introduced by click addition of mercaptoethanol and a double bond in the intermediate to obtain a modified monomer, which is copolymerized with polypropylene glycol and isophorone diisocyanate and introduced into a polyurethane macromolecular chain by blocks. During the polyurethane slurry blending process, sulfur and nitrogen elements in the modified monomer chain segments form a chelating effect, and light calcium powder particles are enriched at the block position, and the particles form initial internal stress at the block position. During the alkali solution leaching process, the silicon nitrogen structure in the modified monomer chain segment is hydrolyzed, so that the stress at the block position is preferentially released to form uniform microscopic gaps, which greatly increases the air permeability of the leather. The detached siloxane structure is in-situ loaded on the surface of the light calcium powder for surface modification, so that the compatibility of the light calcium powder with the polymer is improved, and the leather maintains good mechanical properties. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1, preparing microfiber leather with good air permeability, the specific implementation process is as follows:

[0025] 1. Preparation of modified polyurethane

[0026] Step A1: Mix diallylamine, triethylamine and anhydrous tetrahydrofuran, introduce dry nitrogen protection, then add trimethoxysilyl chloride and mix well, heat to 65°C, stir at 180rpm, and react for 3h, wherein the amount ratio of diallylamine, trimethoxysilyl chloride, triethylamine and anhydrous tetrahydrofuran is 0.1mol:0.1mol:10mL:30mL, then remove tetrahydrofuran by rotary evaporation to obtain an intermediate.

[0027] Step A2: Mix the intermediate, mercaptoethanol, dimethylphenylphosphine and acetone, introduce nitrogen protection, and apply stirring at 50 rpm and 200 W / m at room temperature. 2 The reaction was carried out under ultraviolet irradiation for 6 hours, wherein the usage ratio of the intermediate, mercaptoethanol, dimethylphenylphosphine and acetone was 0.1 mol: 0.2 mol: 30 mg: 80 mL, and then the acetone was evaporated under reduced pressure to obtain a modified monomer.

[0028] Step A3: Take isophorone diisocyanate and polypropylene glycol (Mn=3000) as a substrate, add dibutyltin dilaurate, heat to 90°C, stir at 60rpm, react for 1.5h, then add modified monomer and continue to react for 2h, wherein the molar ratio of isocyanate group and hydroxyl group of isophorone diisocyanate and polypropylene glycol is 1:0.85, the amount of modified monomer is 12wt% of the substrate, the amount of dibutyltin dilaurate is 1.5‰ of the substrate, then add 10wt% of methanol to mix, and cool the reactants to below 50°C to obtain modified polyurethane.

[0029] 2. Preparation of microfiber leather

[0030] Step S1: Take the raw materials according to weight parts, 40 parts of modified polyurethane, which is homemade in this embodiment; 2.8 parts of light calcium powder, commercially available 1000 mesh micropowder; 0.25 parts of defoamer, JY-800 type silicone defoamer; 0.08 parts of light stabilizer, selected from liquid light stabilizer 292; 50 parts of ethyl acetate, industrial grade raw material; first premix the light calcium powder, defoamer, light stabilizer and ethyl acetate in a disperser at 1200 rpm for 10 minutes, then add the modified polyurethane and mix well to obtain a polyurethane slurry.

[0031] Step S2: repeatedly impregnating and drying the microfiber base in the polyurethane slurry, and controlling the dry weight increment to be 15±0.5wt%, to obtain a composite leather.

[0032] Step S3: prepare a sodium hydroxide aqueous solution with a mass fraction of 10% as an alkali solution, immerse and roll the composite leather twice in the alkali solution, the temperature of the alkali solution is 80° C., then wash with water until the washing liquid is neutral, and dry to obtain a microfiber leather with good air permeability.

[0033] Example 2, preparing microfiber leather with good air permeability, the specific implementation process is as follows:

[0034] 1. Preparation of modified polyurethane

[0035] Step A1: Mix diallylamine, triethylamine and anhydrous tetrahydrofuran, introduce dry nitrogen protection, then add trimethoxysilyl chloride and mix well, heat to 55°C, stir at 120rpm, and react for 4h, wherein the amount ratio of diallylamine, trimethoxysilyl chloride, triethylamine and anhydrous tetrahydrofuran is 0.1mol:0.1mol:6mL:20mL, then remove tetrahydrofuran by rotary evaporation to obtain an intermediate.

[0036] Step A2: Mix the intermediate, mercaptoethanol, dimethylphenylphosphine and acetone, introduce nitrogen protection, and apply stirring at 30 rpm and 150 W / m at room temperature. 2The reaction was carried out under ultraviolet irradiation for 8 hours, wherein the usage ratio of the intermediate, mercaptoethanol, dimethylphenylphosphine and acetone was 0.1 mol: 0.2 mol: 20 mg: 60 mL, and then the acetone was evaporated under reduced pressure to obtain a modified monomer.

[0037] Step A3: Take isophorone diisocyanate and polypropylene glycol (Mn=2000) as a substrate, add dibutyltin dilaurate, heat to 80°C, stir at 40rpm, react for 2h, then add modified monomer and continue to react for 3h, wherein the molar ratio of isocyanate group and hydroxyl group of isophorone diisocyanate and polypropylene glycol is 1:0.68, the amount of modified monomer is 18wt% of the substrate, the amount of dibutyltin dilaurate is 1‰ of the substrate, then add 10wt% of the substrate methanol to mix, and cool the reactants to below 50°C to obtain modified polyurethane.

[0038] 2. Preparation of microfiber leather

[0039] Step S1: Take the raw materials according to weight parts, 50 parts of modified polyurethane, which is homemade in this embodiment; 3.5 parts of light calcium powder, commercially available 1000 mesh micropowder; 0.35 parts of defoamer, JY-800 type silicone defoamer; 0.05 parts of light stabilizer, selected from liquid light stabilizer 292; 60 parts of ethyl acetate, industrial grade raw material; first premix the light calcium powder, defoamer, light stabilizer and ethyl acetate in a disperser at 1200 rpm for 13 minutes, then add the modified polyurethane and mix well to obtain a polyurethane slurry.

[0040] Step S2: repeatedly impregnating and drying the microfiber base in the polyurethane slurry, and controlling the dry weight increment to be 15±0.5wt%, to obtain a composite leather.

[0041] Step S3: prepare a sodium hydroxide aqueous solution with a mass fraction of 10% as an alkali solution, immerse and roll the composite leather twice in the alkali solution, the temperature of the alkali solution is 80° C., then wash with water until the washing liquid is neutral, and dry to obtain a microfiber leather with good air permeability.

[0042] Example 3, preparing microfiber leather with good air permeability, the specific implementation process is as follows:

[0043] 1. Preparation of modified polyurethane

[0044] Step A1: Mix diallylamine, triethylamine and anhydrous tetrahydrofuran, introduce dry nitrogen protection, then add trimethoxysilyl chloride and mix well, heat to 60°C, stir at 180rpm, and react for 3.5h, wherein the amount ratio of diallylamine, trimethoxysilyl chloride, triethylamine and anhydrous tetrahydrofuran is 0.1mol: 0.1mol: 8mL: 25mL, then remove tetrahydrofuran by rotary evaporation to obtain an intermediate.

[0045] Step A2: Mix the intermediate, mercaptoethanol, dimethylphenylphosphine and acetone, introduce nitrogen protection, and apply stirring at 40 rpm and 180 W / m at room temperature. 2 The reaction was carried out under ultraviolet irradiation for 7 hours, wherein the usage ratio of the intermediate, mercaptoethanol, dimethylphenylphosphine and acetone was 0.1 mol: 0.2 mol: 25 mg: 70 mL, and then the acetone was evaporated under reduced pressure to obtain a modified monomer.

[0046] Step A3: Take isophorone diisocyanate and polypropylene glycol (Mn=3000) as a substrate, add dibutyltin dilaurate, heat to 85°C, stir at 60rpm, react for 1.7h, then add modified monomer and continue to react for 2.2h, wherein the molar ratio of isocyanate group and hydroxyl group of isophorone diisocyanate and polypropylene glycol is 1:0.75, the amount of modified monomer is 15wt% of the substrate, the amount of dibutyltin dilaurate is 1.2‰ of the substrate, then add 10wt% of the substrate methanol to mix, and cool the reactants to below 50°C to obtain modified polyurethane.

[0047] 2. Preparation of microfiber leather

[0048] Step S1: Take the raw materials according to weight parts, 44 parts of modified polyurethane, which is self-made in this embodiment; 3 parts of light calcium powder, commercially available 1000 mesh micropowder; 0.3 parts of defoamer, JY-800 type silicone defoamer; 0.08 parts of light stabilizer, selected from liquid light stabilizer 292; 55 parts of ethyl acetate, industrial grade raw material; first premix the light calcium powder, defoamer, light stabilizer and ethyl acetate in a disperser at 1200 rpm for 10 minutes, then add the modified polyurethane and mix well to obtain a polyurethane slurry.

[0049] Step S2: repeatedly impregnating and drying the microfiber base in the polyurethane slurry, and controlling the dry weight increment to be 15±0.5wt%, to obtain a composite leather.

[0050] Step S3: prepare a sodium hydroxide aqueous solution with a mass fraction of 10% as an alkali solution, immerse and roll the composite leather twice in the alkali solution, the temperature of the alkali solution is 80° C., then wash with water until the washing liquid is neutral, and dry to obtain a microfiber leather with good air permeability.

[0051] Example 4, preparing microfiber leather with good air permeability, the specific implementation process is as follows:

[0052] 1. Preparation of modified polyurethane

[0053] Step A1: Mix diallylamine, triethylamine and anhydrous tetrahydrofuran, introduce dry nitrogen protection, then add trimethoxysilyl chloride and mix well, heat to 60°C, stir at 180rpm, and react for 3.8h, wherein the amount ratio of diallylamine, trimethoxysilyl chloride, triethylamine and anhydrous tetrahydrofuran is 0.1mol: 0.1mol: 7mL: 30mL, then remove tetrahydrofuran by rotary evaporation to obtain an intermediate.

[0054] Step A2: Mix the intermediate, mercaptoethanol, dimethylphenylphosphine and acetone, introduce nitrogen protection, and apply stirring at 40 rpm and 200 W / m at room temperature. 2 The reaction was carried out under ultraviolet irradiation for 6.5 hours, wherein the usage ratio of the intermediate, mercaptoethanol, dimethylphenylphosphine and acetone was 0.1 mol: 0.2 mol: 30 mg: 70 mL, and then the acetone was evaporated under reduced pressure to obtain a modified monomer.

[0055] Step A3: Take isophorone diisocyanate and polypropylene glycol (Mn=3000) as a substrate, add dibutyltin dilaurate, heat to 80°C, stir at 60rpm, react for 1.8h, then add modified monomer and continue to react for 2.5h, wherein the molar ratio of isocyanate group and hydroxyl group of isophorone diisocyanate and polypropylene glycol is 1:0.72, the amount of modified monomer is 16wt% of the substrate, the amount of dibutyltin dilaurate is 1.4‰ of the substrate, then add 10wt% of methanol to mix, and cool the reactants to below 50°C to obtain modified polyurethane.

[0056] 2. Preparation of microfiber leather

[0057] Step S1: Take the raw materials according to weight parts, 48 ​​parts of modified polyurethane, which is self-made in this embodiment; 3.2 parts of light calcium powder, commercially available 1000 mesh micropowder; 0.3 parts of defoamer, JY-800 type silicone defoamer; 0.08 parts of light stabilizer, selected from liquid light stabilizer 292; 60 parts of ethyl acetate, industrial grade raw material; first premix the light calcium powder, defoamer, light stabilizer and ethyl acetate in a disperser at 1200 rpm for 12 minutes, then add the modified polyurethane and mix well to obtain a polyurethane slurry.

[0058] Step S2: repeatedly impregnating and drying the microfiber base in the polyurethane slurry, and controlling the dry weight increment to be 15±0.5wt%, to obtain a composite leather.

[0059] Step S3: prepare a sodium hydroxide aqueous solution with a mass fraction of 10% as an alkali solution, immerse and roll the composite leather twice in the alkali solution, the temperature of the alkali solution is 80° C., then wash with water until the washing liquid is neutral, and dry to obtain a microfiber leather with good air permeability.

[0060] Comparative Example 1

[0061] In this comparative example, CRISVON SPM-12 polyurethane produced by DIC Corporation is used to replace modified polyurethane to prepare microfiber leather, and the specific implementation process is the same as that in Example 4.

[0062] Comparative Example 2

[0063] This comparative example is the 134-grain microfiber leather produced by Jiangsu Kemei New Materials Co., Ltd.

[0064] Samples were taken from the prepared microfiber leather, and the thickness of the samples was measured according to the QB / T 3812.4-1999 standard; the mechanical properties of the samples were tested according to the QB / T 3812.5-1999 standard; the folding resistance of the samples was tested according to the GB / T3819-1997 standard; the air permeability of the samples was tested according to the GB / T 5453-1997 standard; the specific test data are shown in the following table:

[0065]

[0066]

[0067] It can be seen from the test results in the above table that the microfiber leather prepared in the embodiment has good mechanical properties and bending resistance, so that the leather has good durability and meets the use requirements of most artificial leather products. The air permeability reaches more than 300 mm / s, and has excellent air permeability.

[0068] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0069] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A microfiber leather with good air permeability, which is composited by a microfiber base cloth and a polyurethane slurry, characterized in that: The polyurethane slurry comprises, by weight: 40-50 parts of modified polyurethane, 2.8-3.5 parts of light calcium powder, 0.25-0.35 parts of defoamer, 0.05-0.08 parts of light stabilizer and 50-60 parts of ethyl acetate; The modified polyurethane is prepared by the following method: Step A1: diallylamine, triethylamine and anhydrous tetrahydrofuran are mixed, dry nitrogen is introduced for protection, trimethoxysilyl chloride is added and mixed, the temperature is raised to 55-65° C., stirred for reaction for 3-4 hours, and then tetrahydrofuran is removed by rotary evaporation to obtain an intermediate; Step A2: The intermediate, mercaptoethanol, dimethylphenylphosphine and acetone were mixed, nitrogen was introduced for protection, and the mixture was stirred at room temperature and 150-200 W / m 2 UV irradiation, reaction for 6-8h, then evaporation of acetone under reduced pressure to obtain a modified monomer; Step A3: Mix isophorone diisocyanate and polypropylene glycol as substrates, add dibutyltin dilaurate, heat to 80-90°C, stir and react for 1.5-2h, then add modified monomer and continue to react for 2-3h, then add methanol, mix and cool to below 50°C to obtain modified polyurethane.

2. The microfiber leather with good air permeability according to claim 1, characterized in that: The usage ratio of diallylamine, trimethoxysilyl chloride, triethylamine and anhydrous tetrahydrofuran is 0.1 mol: 0.1 mol: 6-10 mL: 20-30 mL.

3. The microfiber leather with good air permeability according to claim 2, characterized in that: The usage ratio of the intermediate, mercaptoethanol, dimethylphenylphosphine and acetone is 0.1 mol: 0.2 mol: 20-30 mg: 60-80 mL.

4. The microfiber leather with good air permeability according to claim 3, characterized in that: The molar ratio of isocyanate group to hydroxyl group of isophorone diisocyanate and polypropylene glycol is 1:0.68-0.85, the amount of the modified monomer is 12-18wt% of the substrate, and the amount of dibutyltin dilaurate is 1-1.5‰ of the substrate.

5. The microfiber leather with good air permeability according to claim 4, characterized in that: The number average molecular weight of polypropylene glycol is 2000-3000.

6. The microfiber leather with good air permeability according to claim 1, characterized in that: The fineness of light calcium powder shall not be less than 800 mesh.

7. The production process of microfiber leather with good air permeability according to any one of claims 1 to 6, characterized in that: Including the following processes: Step S1: premixing light calcium powder, defoaming agent, light stabilizer and ethyl acetate, and then adding modified polyurethane and mixing to obtain polyurethane slurry; Step S2: repeatedly impregnating the microfiber base fabric in the polyurethane slurry and drying the microfiber base fabric, controlling the dry weight increment to be 15±0.5wt% to obtain a composite leather; Step S3: The composite leather is immersed and rolled twice in an alkali solution, then washed with water until the washing liquid is neutral, and dried to obtain a microfiber leather with good air permeability.

8. The production process of a microfiber leather with good air permeability according to claim 7, characterized in that: The alkali solution is a 10% sodium hydroxide aqueous solution, and the alkali solution temperature is 80°C.

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