Breathable and moisture-permeable solvent-free polyurethane synthetic leather and preparation method thereof

Abstract

The invention belongs to the technical field of synthetic leather, and particularly discloses breathable and moisture-permeable solvent-free polyurethane synthetic leather and a preparation method thereof.The breathable and moisture-permeable solvent-free polyurethane synthetic leather comprises base cloth, a solvent-free foaming layer and a solvent-free surface layer, foaming slurry adopted by the solvent-free foaming layer is composed of a polyether polyester mixed type A material prepolymer, a polyether type B material prepolymer, long-chain alkyl siloxane, 2-methyl-1-[4-(methylthio) phenyl]-2-(4-morpholinyl)-1-acetone, color paste and filler. Surface layer slurry adopted by the solvent-free surface layer is composed of a POSS modified polyether mixed type A material prepolymer, a polybutadiene modified polyether type B material prepolymer, a flatting agent, color paste and nano kaolin. According to the invention, 2-methyl-1-[4-(methylthio) phenyl]-2-(4-morpholinyl)-1-acetone is introduced and is decomposed by illumination to generate Lewis base, long-chain alkyl siloxane is catalyzed to generate hydrolytic polycondensation reaction, hydrophobic long-chain organopolysiloxane is formed, micro-nano pores are generated in the polyester synthetic leather, and the breathable and moisture permeable functions are realized.

Description

Technical Field

[0001] The invention belongs to the technical field of synthetic leather, and particularly relates to an air-permeable, moisture-permeable, solvent-free polyurethane synthetic leather and a preparation method thereof. Background Art

[0002] Polyurethane synthetic leather has the advantages of soft hand feel, resistance to bending, wear and cold, easy production, and high cost performance. It is the most ideal substitute for natural leather and has broad application prospects in the fields of footwear, clothing, luggage, etc. Traditional solvent-based polyurethane synthetic leather replaces the dimethylformamide (DMF) solvent in the solvent-based polyurethane resin with water, so that the polyurethane coating has continuous pores, so that the prepared synthetic leather has certain moisture permeability and air permeability. However, during the production process of solvent-based polyurethane synthetic leather, a large amount of DMF waste liquid and waste gas will be generated, which pollutes the environment, causing many countries to begin to restrict the production and application of solvent-based polyurethane synthetic leather.

[0003] Solvent-free polyurethane synthetic leather is a new type of environmentally friendly product developed in recent years based on a clean production process. Compared with traditional solvent-based polyurethane synthetic leather, it has less pollution and has excellent properties such as good mechanical properties, high wear resistance, excellent aging resistance, and strong reprocessability. However, solvent-free polyurethane synthetic leather has poor air and moisture permeability and requires additional punching process to achieve air permeability, which limits its application range. Summary of the invention

[0004] In view of the deficiencies in the prior art, the object of the present invention is to provide a breathable and moisture-permeable solvent-free polyurethane synthetic leather and a preparation method thereof. The present invention introduces long-chain alkyl siloxane and 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone into a foaming slurry, and the photoinitiator 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone is decomposed by light to produce a Lewis base, which can catalyze the siloxane in the long-chain alkyl siloxane to undergo an in-situ hydrolysis and polycondensation reaction to form a hydrophobic long-chain organic polysiloxane, resulting in the phase separation of the hydrophobic long-chain organic polysiloxane from the polyurethane molecular chain, and generating regular breathable and moisture-permeable micro-nano pores in the polyurethane synthetic leather, thereby realizing the breathable and moisture-permeable function of the polyurethane synthetic leather, and effectively solving the problems in the background technology.

[0005] The present invention is achieved through the following technical solutions: A breathable and moisture-permeable solvent-free polyurethane synthetic leather comprises a base fabric, and a solvent-free foaming layer and a solvent-free surface layer which are sequentially arranged on the base fabric. The foaming slurry used in the solvent-free foaming layer consists of a polyether polyester mixed type A material prepolymer, a polyether type B material prepolymer, a long-chain alkyl siloxane, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone, a color paste and a filler; the surface layer slurry used in the solvent-free surface layer consists of a POSS-modified polyether mixed type A material prepolymer, a polybutadiene-modified polyether type B material prepolymer, a leveling agent, a color paste and nano-kaolin.

[0006] A further improvement of the present invention is: The foaming slurry is composed of the following raw materials in parts by weight: 40-60 parts of polyether polyester mixed type A material prepolymer; 15-20 parts of polyether type B material prepolymer; 2-5 parts of long chain alkyl siloxane; 0.1-0.4 parts of 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone; 1-2 parts of color paste; 20-25 servings of filling.

[0007] Furthermore, the filler consists of nano kaolin, attapulgite clay, ultrafine dolomite and barium sulfate.

[0008] A further improvement of the present invention is: The surface slurry is composed of the following raw materials in parts by weight: 30-40 parts of POSS modified polyether mixed type A prepolymer; 15-20 parts of polybutadiene modified polyether type B material prepolymer; 0.1 part of leveling agent; 1-3 parts of color paste; 4-8 parts of nano kaolin; Mesoporous nano zinc oxide 2-4 parts; 2 parts of dispersant.

[0009] A further improvement of the present invention is: The base fabric is one of woven fabric and non-woven fabric.

[0010] A further improvement of the present invention is: A method for preparing breathable and moisture-permeable solvent-free polyurethane synthetic leather comprises the following steps: S1. Mix polyether polyester mixed type A material prepolymer, long-chain alkyl siloxane, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone and color paste, stir for 10 minutes, add filler, continue stirring for 10 minutes, add polyether type B material prepolymer, stir at high speed for 10 seconds, and obtain foaming slurry; S2, POSS modified polyether mixed type A material prepolymer, water-based color paste, leveling agent are mixed, stirred for 5min, nano kaolin, mesoporous nano zinc oxide, dispersant are added, stirring is continued for 10min, polybutadiene modified polyether type B material prepolymer is added, and high-speed stirring is performed for 10s to obtain a surface layer slurry; S3, coating the surface layer slurry on release paper, and aging in an oven at a step temperature of 90-130° C. at a speed of 8-12 m / min to obtain a solvent-free surface layer; S4, further coating the foaming slurry on the solvent-free surface layer, irradiating with high-pressure mercury lamp for 2-5 seconds, and baking at 100° C. for 50-55 seconds to obtain a solvent-free polyurethane semi-finished product; S5, hot-pressing and laminating the base fabric with the solvent-free polyurethane semi-finished product through a two-roll calender, baking at 130° C. for 5 min, and separating the release paper after cooling to obtain a breathable and moisture-permeable solvent-free polyurethane synthetic leather. Beneficial Effects

[0011] Compared with the prior art, the present invention has the following obvious advantages: 1. The present invention introduces long-chain alkyl siloxane and 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone into the foaming slurry. The photoinitiator 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone is decomposed by light to produce a Lewis base, which can catalyze the in-situ hydrolysis and polycondensation reaction of the siloxane in the long-chain alkyl siloxane to form a hydrophobic long-chain organopolysiloxane, resulting in the phase separation of the hydrophobic long-chain organopolysiloxane from the polyurethane molecular chain, and the formation of regular air-permeable and moisture-permeable micro-nanopores in the polyurethane synthetic leather, thereby realizing the air-permeable and moisture-permeable functions of the polyurethane synthetic leather.

[0012] 2. The present invention uses a polyether mixed type A material prepolymer in the surface slurry, and introduces a POSS cage structure into the polyurethane prepolymer molecular chain, so that the prepared polyurethane synthetic leather surface layer also has intrinsic nanopores, thereby improving its air permeability and moisture permeability.

[0013] 3. The polyether type B material prepolymer used in the surface layer slurry of the present invention introduces polybutadiene into the molecular chain of the polyurethane prepolymer, so that the prepared polyurethane synthetic leather surface layer has better elasticity and improves its mechanical properties. DETAILED DESCRIPTION

[0014] The present invention is described in detail below in conjunction with embodiments. Example 1

[0015] (1) Preparation of solvent-free polyurethane foaming slurry Calculated by weight, 50 parts of polyether polyester mixed type A material prepolymer, 2 parts of long-chain alkyl siloxane, 0.1 parts of 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone, and 1 part of color paste were mixed, stirred for 10 minutes, 20 parts of filler were added, and stirring was continued for 10 minutes, and finally 15 parts of polyether type B material prepolymer were added, and stirred at high speed for 10 seconds to obtain a foaming slurry; (2) Preparation of solvent-free polyurethane surface slurry Calculated by weight, 40 parts of POSS modified polyether mixed type A material prepolymer, 2 parts of water-based color paste, and 0.1 parts of leveling agent were mixed and stirred for 5 minutes, 5 parts of nano kaolin, 2 parts of mesoporous nano zinc oxide, and 2 parts of dispersant were added and stirred for 10 minutes, and finally 20 parts of polybutadiene modified polyether type B material prepolymer were added, and stirred at high speed for 10 seconds to obtain a surface layer slurry; (3) Production of solvent-free polyurethane synthetic leather The surface layer slurry is coated on the release paper, and matured in a step temperature oven at 90-130°C at a speed of 8-12m / min. After drying, the foaming slurry is further coated, irradiated with a high-pressure mercury lamp for 2s, and baked at 100°C for 50-55s. The base fabric is then hot-pressed and laminated with the base fabric through a two-roll calender, baked at 130°C for 5min, and separated from the release paper after cooling to obtain a breathable, moisture-permeable, solvent-free polyurethane synthetic leather. Example 2

[0016] (1) Preparation of solvent-free polyurethane foaming slurry Calculated by weight, 50 parts of polyether polyester mixed type A material prepolymer, 5 parts of long-chain alkyl siloxane, 0.3 parts of 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone, and 1 part of color paste were mixed, stirred for 10 minutes, and then 20 parts of filler were added. After continuing to stir for 10 minutes, 15 parts of polyether type B material prepolymer were finally added, and stirred at high speed for 10 seconds to obtain a foaming slurry; (2) Preparation of solvent-free polyurethane surface slurry Calculated by weight, 40 parts of POSS modified polyether mixed type A material prepolymer, 2 parts of water-based color paste, and 0.1 parts of leveling agent were mixed and stirred for 5 minutes, 5 parts of nano kaolin, 2 parts of mesoporous nano zinc oxide, and 2 parts of dispersant were added and stirred for 10 minutes, and finally 20 parts of polybutadiene modified polyether type B material prepolymer were added, and stirred at high speed for 10 seconds to obtain a surface layer slurry; (3) Production of solvent-free polyurethane synthetic leather The surface layer slurry is coated on the release paper, and matured in a step temperature oven at 90-130°C at a speed of 8-12m / min. After drying, the foaming slurry is further coated, irradiated with a high-pressure mercury lamp for 5s, and baked at 100°C for 50-55s. The base fabric is then hot-pressed and laminated with the base fabric through a two-roll calender, baked at 130°C for 5min, and separated from the release paper after cooling to obtain a breathable, moisture-permeable, solvent-free polyurethane synthetic leather. Example 3

[0017] (1) Preparation of solvent-free polyurethane foaming slurry Calculated by weight, 50 parts of polyether polyester mixed type A material prepolymer, 2 parts of long-chain alkyl siloxane, 0.1 parts of 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone, and 1 part of color paste were mixed, stirred for 10 minutes, 20 parts of filler were added, and stirring was continued for 10 minutes, and finally 15 parts of polyether type B material prepolymer were added, and stirred at high speed for 10 seconds to obtain a foaming slurry; (2) Preparation of solvent-free polyurethane surface slurry Calculated by weight, 40 parts of POSS modified polyether mixed type A material prepolymer, 2 parts of water-based color paste, and 0.1 parts of leveling agent were mixed and stirred for 5 minutes, 8 parts of nano kaolin, 4 parts of mesoporous nano zinc oxide, and 2 parts of dispersant were added and stirred for 10 minutes, and finally 20 parts of polybutadiene modified polyether type B material prepolymer were added, and stirred at high speed for 10 seconds to obtain a surface layer slurry; (3) Production of solvent-free polyurethane synthetic leather The surface layer slurry is coated on the release paper, and matured in a step temperature oven at 90-130°C at a speed of 8-12m / min. After drying, the foaming slurry is further coated, irradiated with a high-pressure mercury lamp for 2s, and baked at 100°C for 50-55s. The base fabric is then hot-pressed and laminated with the base fabric through a two-roll calender, baked at 130°C for 5min, and separated from the release paper after cooling to obtain a breathable, moisture-permeable, solvent-free polyurethane synthetic leather.

[0018] The breathable and moisture permeable solvent-free polyurethane synthetic leathers prepared in Examples 1 to 3 were tested for moisture permeability, air permeability, wear resistance and bending resistance, respectively, using the following methods: Moisture permeability: Test according to the requirements of GB / T 12704-1991.

[0019] Air permeability: Test according to GB / T 5453-1997.

[0020] Abrasion resistance: The prepared breathable, moisture-permeable, solvent-free polyurethane synthetic leather was tested on a TABER friction tester using an H22 grinding wheel to test the number of circles at which the surface of the material began to wear.

[0021] Folding fastness: Test according to the provisions of QB / T 2714-2018.

[0022] The test results are shown in Table 1: Table 1

[0023] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A breathable and moisture-permeable solvent-free polyurethane synthetic leather, comprising a base fabric, and a solvent-free foaming layer and a solvent-free surface layer sequentially arranged on the base fabric, characterized in that: The foaming slurry used in the solvent-free foaming layer consists of a polyether polyester mixed type A material prepolymer, a polyether type B material prepolymer, a long-chain alkyl siloxane, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone, a color paste and a filler; the surface layer slurry used in the solvent-free surface layer consists of a POSS-modified polyether mixed type A material prepolymer, a polybutadiene-modified polyether type B material prepolymer, a leveling agent, a color paste and nano-kaolin.

2. The breathable, moisture-permeable, solvent-free polyurethane synthetic leather according to claim 1, characterized in that: The foaming slurry is composed of the following raw materials in parts by weight: 40-60 parts of polyether polyester mixed type A material prepolymer; 15-20 parts of polyether type B material prepolymer; 2-5 parts of long chain alkyl siloxane; 0.1-0.4 parts of 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone; 1-2 parts of color paste; 20-25 servings of filling.

3. The breathable, moisture-permeable, solvent-free polyurethane synthetic leather according to claim 2, characterized in that: The filler consists of nano kaolin, attapulgite clay, ultrafine dolomite and barium sulfate.

4. The breathable, moisture-permeable, solvent-free polyurethane synthetic leather according to claim 1, characterized in that: The surface slurry is composed of the following raw materials in parts by weight: 30-40 parts of POSS modified polyether mixed type A prepolymer; 15-20 parts of polybutadiene modified polyether type B material prepolymer; 0.1 part of leveling agent; 1-3 parts of color paste; 4-8 parts of nano kaolin; Mesoporous nano zinc oxide 2-4 parts; 2 parts of dispersant.

5. The breathable, moisture-permeable, solvent-free polyurethane synthetic leather according to claim 1, characterized in that: The base fabric is one of woven fabric and non-woven fabric.

6. The method for preparing a breathable and moisture-permeable solvent-free polyurethane synthetic leather according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Mix polyether polyester mixed type A material prepolymer, long-chain alkyl siloxane, 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone and color paste, stir for 10 minutes, add filler, continue stirring for 10 minutes, add polyether type B material prepolymer, stir at high speed for 10 seconds, and obtain foaming slurry; S2, POSS modified polyether mixed type A material prepolymer, water-based color paste, leveling agent are mixed, stirred for 5min, nano kaolin, mesoporous nano zinc oxide, dispersant are added, stirring is continued for 10min, polybutadiene modified polyether type B material prepolymer is added, and high-speed stirring is performed for 10s to obtain a surface layer slurry; S3, coating the surface layer slurry on release paper, and aging in an oven at a step temperature of 90-130° C. at a speed of 8-12 m / min to obtain a solvent-free surface layer; S4, further coating the foaming slurry on the solvent-free surface layer, irradiating with high-pressure mercury lamp for 2-5 seconds, and baking at 100° C. for 50-55 seconds to obtain a solvent-free polyurethane semi-finished product; S5, hot-pressing and laminating the base fabric with the solvent-free polyurethane semi-finished product through a two-roll calender, baking at 130° C. for 5 min, and separating the release paper after cooling to obtain a breathable and moisture-permeable solvent-free polyurethane synthetic leather.

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