Polyurethane synthetic leather for vulcanized shoes and preparation method thereof

Abstract

The invention discloses polyurethane synthetic leather for vulcanized shoes and a preparation method of the polyurethane synthetic leather. The polyurethane synthetic leather sequentially comprises a cotton-velvet-like base cloth layer, a solvent-free bonding layer, a water-based dry-process middle layer and a water-based dry-process surface layer from inside to outside, the preparation method comprises the following steps: coating water-based dry-process surface layer slurry on release paper, and controlling gradient temperature for drying and curing to form a water-based dry-process surface layer; coating the inner side surface of the water-based dry-method surface layer with water-based intermediate layer slurry, and controlling gradient temperature for drying and curing to form a water-based intermediate layer; the water-based middle layer is coated with solvent-free A / B material resin slurry, and after a high-temperature reaction, the high-density knitted imitation lint base cloth is compounded through a pair roller; the preparation process provided by the invention is simple, green and environment-friendly, and the prepared polyurethane synthetic leather for the vulcanized shoes has high composite strength, high wear resistance and folding resistance, and is suitable for manufacturing the vulcanized shoe leather.

Description

Technical Field

[0001] The invention belongs to the technical field of vulcanized shoe leather materials, and particularly relates to a vulcanized polyurethane synthetic leather for shoes and a preparation method thereof. Background Art

[0003] The scale of the domestic men's and women's shoes and leather products supporting industry is huge. At present, vulcanized shoes have become a popular trend: 1) Young and fashionable, vulcanized shoes with their simple shape and strong elasticity, with jeans, casual pants, sports pants have become a classic, and vulcanized shoes are also easy to clean; 2) Lightweight, vulcanized shoes with their special materials and craftsmanship, will feel very light on the feet, plus the extremely tough rubber soles. As a new generation of environmentally friendly artificial synthetic leather materials, high-performance water-based polyurethane has excellent strength, scratch resistance, wear resistance and other advantages. It has become an indispensable material for high physical properties. The application of water-based environmentally friendly materials is conducive to ecological protection and reducing VOC emissions. Since consumer shoe leather products involve different areas of people's daily life, the project products have the characteristics of multi-field multi-function, with diverse colors, varied textures, comfortable touch, scratch resistance, wear resistance, yellowing resistance, and excellent bending resistance. At the same time, it meets the customer's high temperature processability, low shrinkage, and achieves pure green and pollution-free. It can be used for a variety of high-performance, complex-shaped vulcanized shoes, and is at the forefront of fashion, innovation, and environmental protection. Summary of the invention

[0004] In view of the problems of low adhesive strength, poor high temperature vulcanization processing, decreased peel strength after vulcanization and poor bending resistance of water-based solvent-free products, the purpose of the present invention is to provide a polyurethane synthetic leather for vulcanized shoes and a preparation method thereof. The polyurethane synthetic leather for vulcanized shoes adopts a water-based solvent-free online pasting process to prepare the product technology to meet the requirements of high physical properties, multi-functions and personalization, and the technical content and added value of the product will be higher. The patented product uses water-based polyurethane materials and solvent-free resins in the entire manufacturing process, does not use any organic solvents and restricted chemicals, and greatly reduces volatile organic compounds (VOCs) compared with traditional polyurethane synthetic leather. The technical level of the product of the present invention is leading in China, not only has the innovation of process and formula, but can also be widely used in the processing and production of vulcanized shoes, can meet the requirements of industrial mass production, replace genuine leather, imported synthetic leather, and traditional oily products, and can also meet consumers' requirements for product quality and appearance.

[0005] The preparation process provided by the invention is green, environmentally friendly and pollution-free, and the obtained product has excellent high-temperature resistant processing performance. The prepared polyurethane synthetic leather for vulcanized shoes is green, environmentally friendly and has high physical properties. When used as vulcanized shoes, it has excellent yellowing resistance and folding resistance and soft touch. It not only integrates fashion, beauty and durability, but also brings the concepts of green, environmental protection and health into the men's and women's vulcanized shoe market.

[0006] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0007] A vulcanized polyurethane synthetic leather for shoes, which comprises, from inside to outside, a cotton flannel-like base fabric layer, a solvent-free adhesive layer, a water-based dry-process middle layer and a water-based dry-process surface layer; the solvent-free adhesive layer makes the product have high peeling strength and good high temperature resistance and vulcanization resistance; the water-based dry-process surface layer and the dry-process middle layer can improve the wear resistance and folding resistance of the product and improve the surface color fastness; wherein:

[0008] The raw material of the imitation cotton velvet base fabric layer is high-density knitted imitation cotton velvet base fabric, and its gram weight is 230±10g / m 2 , thickness: 0.80±0.03mm;

[0009] The solvent-free adhesive layer is prepared by using a solvent-free A / B material resin slurry, and the solvent-free A / B material resin slurry is prepared by the following components in parts by weight:

[0010]

[0011] The water-based dry-process intermediate layer is prepared from a water-based dry-process intermediate layer slurry. The water-based dry-process intermediate layer slurry is used in combination with two types of sulfonic acid polyurethane resins with two moduli. The slurry is prepared from the following components in parts by weight:

[0012]

[0013] Among them: the elastic modulus of the water-based polyether sulfonic acid polyurethane resin is lower than 3MPa, and the elastic modulus of the water-based polyester sulfonic acid polyurethane resin is greater than 6MPa.

[0014] Since the traditional carboxylic acid type water-based resin introduces dimethylol propionic acid (DMPA), when the water-based polyurethane is dried to form a film, the polyurethane becomes weakly acidic, which will affect the molecular chain growth of the solvent-free adhesive layer. However, the sulfonic acid polyurethane resin synthesized by sulfonate polymer polyol will not become weakly acidic when dried to form a film, and the initial peel strength of the solvent-free adhesive layer is high. Therefore, the water-based dry process intermediate layer slurry of the present invention uses sulfonic acid polyurethane resin; in order to further improve the product performance, the present invention uses two sulfonic acid polyurethane resins with different elastic moduli for use.

[0015] The water-based dry surface layer is prepared from a water-based dry surface layer slurry, and two polyurethane resins with two elastic moduli are used in combination, and the water-based dry surface layer is prepared from the following components in parts by weight:

[0016]

[0017] Among them: the elastic modulus of water-based polyether sulfonic acid polyurethane resin is lower than 3MPa, and the elastic modulus of water-based polyester polyurethane resin is greater than 6MPa.

[0018] The present invention also discloses a method for preparing the vulcanized polyurethane synthetic leather for shoes as described above, comprising the following steps:

[0019] S1. Coating a water-based dry surface slurry on the release paper, controlling the gradient temperature to 90° C., 100° C., 110° C., 130° C., and 140° C. for drying and curing to form a water-based dry surface layer, wherein the thickness of the water-based dry surface layer is 0.04 to 0.06 mm;

[0020] S2, coating the water-based intermediate layer slurry on the inner side of the water-based dry surface layer, controlling the gradient temperature to 90°C, 100°C, 110°C, 130°C, and 140°C for drying and curing to form a water-based intermediate layer; the thickness of the water-based intermediate layer is 0.05-0.06mm;

[0021] S3, coating the solvent-free A / B material resin slurry on the water-based intermediate layer, and after high-temperature reaction, compounding the high-density knitted imitation cotton flannel base fabric through a pair of rollers; and then after high-temperature online reaction, aging at room temperature, peeling off the release paper to obtain the final product. The temperature of the high-temperature reaction is 100-120°C, the temperature of the high-temperature online reaction is 130-140°C, and the thickness of the solvent-free adhesive layer formed is 0.40-0.45mm;

[0022] Preferably, the high-density knitted cotton-like fleece is preheated before being laminated with the solvent-free A / B material resin slurry at high temperature, and the high-temperature laminating temperature of the high-density knitted cotton-like fleece and the solvent-free A / B material resin slurry is 100° C.; the room temperature aging time is 20 minutes.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1) The vulcanized polyurethane synthetic leather for shoes provided by the present invention adopts a fully aqueous solvent-free laminating process in preparation, which is green, environmentally friendly and pollution-free. The N,N-dimethylformamide (DMF) in the finished product of the vulcanized polyurethane synthetic leather for shoes can be lower than 5ppm, which is compared with the DMF content in traditional synthetic leather, thereby ensuring the chemical safety to the environment and human body.

[0025] 2) The dry surface layer and the middle layer of the vulcanized polyurethane synthetic leather for shoes provided by the present invention are matched with different modulus water-based resins during preparation to improve the performance of each layer. The principle is: high modulus resin can improve the stiffness and strength of the material, but the bending resistance is poor, and low modulus resin has good elongation and can improve the bending of the surface. The present invention balances the performance defects of each of the high modulus resin and the low modulus resin by using a specific type of high modulus resin and a low modulus resin in combination. The dry surface layer prepared by the present invention can meet the requirements of high wear resistance of the leather surface, and the middle layer can meet the high peeling combination with the solvent-free adhesive layer, and can achieve the physical property requirements of various complex patterns, high temperature resistance, yellowing resistance, and bending resistance, which meets the processing requirements of vulcanized polyurethane synthetic leather for shoes in men's and women's shoes.

[0026] 3) The vulcanized polyurethane synthetic leather for shoes of the present invention is designed according to the current strict control of restricted substances of environmentally friendly chemicals, and a high-performance polyurethane solvent-free A / B material resin formula is designed, and the use of organic tin catalysts is abandoned, and environmentally friendly amine and metal catalysts are used, so that the product has very high peel strength and product properties;

[0027] 4) The present invention designs a surface water-based formula based on the processing technology of vulcanized shoe leather products, and uses an open isocyanate cross-linking agent in the water-based dry surface layer to improve the bending resistance of the surface layer, so that the surface layer can be highly bonded with the shoe glue through chemical bonds, so that the product has excellent sole adhesive properties, while improving the product's high temperature resistance and bending resistance after high-temperature vulcanization; using a blocked isocyanate cross-linking agent in the water-based dry intermediate layer can improve the bonding strength between the water-based intermediate layer and the solvent-free adhesive layer. The principle is that the blocked isocyanate cross-linking agent deblocks the NCO functional group at high temperature to avoid premature self-cross-linking of the water-based intermediate layer, so that it can have a strong bond energy bond with the solvent-free adhesive layer, thereby improving the bonding strength between the two. DETAILED DESCRIPTION

[0028] The technical scheme of the present invention is further described in detail below in conjunction with the examples. The following examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods used in the following examples are conventional methods unless otherwise specified; the reagents and materials used are all commercially available unless otherwise specified.

[0029] The names, uses and specifications of some products used in the following examples are shown in Table 1;

[0030] Table 1 Product name, use and specification

[0031]

[0032]

[0033] The above are merely optional product specifications and purchasing manufacturers of the raw material components involved in the present invention, and the raw material components of the present invention are not limited to the above acquisition methods.

[0034] Example 1

[0035] A method for preparing vulcanized polyurethane synthetic leather for shoes comprises the following steps:

[0036] The following raw material components in parts by weight: 100 parts of polyester polyurethane resin JF-PDY-851MY, 10 parts of water-based color paste TSE LR01, 5 parts of water-based crosslinking agent Aquolin 166, 0.3 parts of water-based defoaming agent DF-2459, 0.10 parts of water-based leveling agent LA-91-120, and 1.0 parts of water-based thickener ALA were fully stirred in a stirring device for 20 minutes and then mixed to prepare a water-based dry surface slurry;

[0037] The water-based dry surface slurry was coated on the release paper, and the gradient temperature was controlled to be 90 / 100 / 110 / 130 / 140°C in five ovens for curing, and the thickness of the formed water-based dry surface layer was 0.06 mm;

[0038] The following raw material components in parts by weight: polyether sulfonic acid polyurethane resin 100 parts of 5215, 10 parts of water-based color paste TSE LR01, 3 parts of water-based crosslinking agent R-700, 0.3 parts of water-based defoaming agent DF-2459, 0.10 parts of water-based leveling agent LA-91-120, and 1.0 parts of water-based thickener ALA are mixed in a stirring device and stirred for 20 minutes to prepare a water-based intermediate layer slurry;

[0039] A water-based intermediate layer slurry is coated on the inner side of the water-based dry surface layer. The water-based intermediate layer slurry is cured in five ovens at a gradient temperature of 90 / 100 / 110 / 130 / 140°C. The thickness of the formed water-based intermediate layer is 0.06mm.

[0040] The following raw material components in parts by weight are weighed to prepare solvent-free A / B material resin slurry: 100 parts of polyether polyol resin CC6945 / 5310A; 125 parts of isocyanate resin AL-5040B; 0.02 parts of environmentally friendly amine catalyst CC 6945 / 92C-CC; 0.4 parts of environmentally friendly metal catalyst CC 6945 / 90C-CC; 30 parts of calcium carbonate filler; the solvent-free A / B material resin slurry is evenly mixed and coated on the surface of the aqueous intermediate layer, and subjected to high-temperature reaction in an environment of 120° C. After the high-temperature reaction, high-density knitted imitation cotton lint is compounded by rollers, and then subjected to high-temperature online reaction at 140° C., and the release paper is peeled off after aging at room temperature to obtain water-based solvent-free vulcanized polyurethane synthetic leather for shoes; wherein: the high-density knitted imitation cotton lint is preheated before being laminated with the solvent-free A / B material resin slurry at high temperature, and the thickness of the formed solvent-free bonding layer is 0.40 mm.

[0041] Example 2

[0042] A method for preparing vulcanized polyurethane synthetic leather for shoes comprises the following steps:

[0043] The following raw material components by mass: 20 parts of polyester polyurethane resin JF-PDY-851MY, polyether sulfonic acid polyurethane resin 5215 80 parts, water-based color paste TSE LR01 10 parts, water-based crosslinking agent Aquolin166 5 parts, water-based defoamer DF-2459 0.3 parts, water-based leveling agent LA-91-120 0.10 parts, water-based thickener ALA 1.0 parts, stir well in a stirring device for 20 minutes and then mix to form a water-based dry surface slurry;

[0044] Coat the release paper with water-based dry surface slurry, control the gradient temperature to 90 / 100 / 110 / 130 / 140°C for drying and curing, and the thickness of the formed water-based dry surface layer is 0.04mm;

[0045] The following raw material components in parts by weight: polyether sulfonic acid polyurethane resin 100 parts of 5215, 10 parts of water-based color paste TSE LR01, 3 parts of water-based crosslinking agent Impraifx R-700, 0.3 parts of water-based defoaming agent DF-2459, 0.10 parts of water-based leveling agent LA-91-120, and 1.0 parts of water-based thickener ALA are fully stirred in a stirring device for 20 minutes and then mixed to form a water-based intermediate layer slurry;

[0046] A water-based intermediate layer slurry is applied to the inner side of the water-based dry surface layer. The water-based intermediate layer slurry is dried and solidified at a gradient temperature of 90 / 100 / 110 / 130 / 140°C. The thickness of the formed water-based intermediate layer is 0.05mm.

[0047] The following raw material components in parts by weight are weighed to prepare solvent-free A / B material resin slurry: 100 parts of polyether polyol resin CC6945 / 5310A; 125 parts of isocyanate resin AL-5040B; 0.02 parts of environmentally friendly amine catalyst CC 6945 / 92C-CC; 0.4 parts of environmentally friendly metal catalyst CC 6945 / 90C-CC; 30 parts of calcium carbonate filler; the solvent-free A / B material resin slurry is evenly mixed and coated on the surface of the aqueous intermediate layer, and subjected to high-temperature reaction in an environment of 120° C. After the high-temperature reaction, high-density knitted imitation cotton lint is compounded by rollers, and then subjected to high-temperature online reaction at 140° C., and the release paper is peeled off after aging at room temperature to obtain water-based solvent-free vulcanized polyurethane synthetic leather for shoes; wherein: the high-density knitted imitation cotton lint is preheated before being laminated with the solvent-free A / B material resin slurry at high temperature, and the thickness of the formed solvent-free bonding layer is 0.40 mm.

[0048] Example 3

[0049] A method for preparing vulcanized polyurethane synthetic leather for shoes comprises the following steps:

[0050] The following raw material components by mass: 30 parts of polyester polyurethane resin JF-PDY-851MY, 30 parts of polyether sulfonic acid polyurethane resin 5215 70 parts, water-based color paste TSE LR01 10 parts, water-based crosslinking agent Aquolin166 5 parts, water-based defoamer DF-2459 0.3 parts, water-based leveling agent LA-91-120 0.10 parts, water-based thickener ALA 1.0 parts, stir well in a stirring device for 20 minutes and then mix to form a water-based dry surface slurry;

[0051] Coat the release paper with water-based dry surface slurry, control the gradient temperature to 90 / 100 / 110 / 130 / 140°C for drying and curing, and the thickness of the formed water-based dry surface layer is 0.04mm;

[0052] The following raw material components in parts by weight: polyether sulfonic acid polyurethane resin 5215 20 parts, polyester sulfonic acid polyurethane resin JF-PDY-877HY 80 parts, water-based color paste TSE LR01 10 parts, water-based crosslinking agent ImpraifxR-700 3 parts, water-based defoamer DF-2459 0.3 parts, water-based leveling agent LA-91-120 0.10 parts, water-based thickener ALA 1.0 parts, stir well in a stirring device for 20 minutes and then mix to form a water-based intermediate layer slurry;

[0053] A water-based intermediate layer slurry is coated on the inner side of the water-based dry surface layer. The water-based intermediate layer slurry is dried and solidified at a gradient temperature of 90 / 100 / 110 / 130 / 140°C to form a water-based intermediate layer with a thickness of 0.05 mm.

[0054] The following raw material components in parts by weight are weighed to prepare solvent-free A / B material resin slurry: 100 parts of polyether polyol resin CC6945 / 5310A; 125 parts of isocyanate resin AL-5040B; 0.02 parts of environmentally friendly amine catalyst CC 6945 / 92C-CC; 0.4 parts of environmentally friendly metal catalyst CC 6945 / 90C-CC; 30 parts of calcium carbonate filler; the solvent-free A / B material resin slurry is evenly mixed and coated on the surface of the aqueous intermediate layer, and a high-temperature reaction is carried out in an environment of 120° C. After the high-temperature reaction, it is compounded with high-density knitted imitation cotton lint by rollers, and then subjected to a high-temperature online reaction at 140° C., and the release paper is peeled off after aging at room temperature to obtain a water-based solvent-free vulcanized polyurethane synthetic leather for shoes; wherein: the high-density knitted imitation cotton lint is preheated before being laminated with the solvent-free A / B material resin slurry at high temperature, and the thickness of the formed solvent-free bonding layer is 0.40 mm.

[0055] Comparative Example 1

[0056] A method for preparing vulcanized polyurethane synthetic leather for shoes comprises the following steps:

[0057] The following raw material components by mass: 30 parts of polyester polyurethane resin JF-PDY-851MY, 30 parts of polyether sulfonic acid polyurethane resin 5215 70 parts, water-based color paste TSE LR01 10 parts, water-based crosslinking agent Aquolin166 5 parts, water-based defoamer DF-2459 0.3 parts, water-based leveling agent LA-91-120 0.10 parts, water-based thickener ALA 1.0 parts, stir well in a stirring device for 20 minutes and then mix to form a water-based dry surface slurry;

[0058] Coat the release paper with water-based dry surface slurry, control the gradient temperature to 90 / 100 / 110 / 130 / 140°C for drying and curing, and the thickness of the formed water-based dry surface layer is 0.04mm;

[0059] The following raw material components in parts by weight: polyether sulfonic acid polyurethane resin 5215 20 parts, polyester sulfonic acid polyurethane resin JF-PDY-877HY 80 parts, water-based color paste TSE LR01 10 parts, water-based crosslinking agent ImpraifxR-700 3 parts, water-based defoamer DF-2459 0.3 parts, water-based leveling agent LA-91-120 0.10 parts, water-based thickener ALA 1.0 parts, stir well in a stirring device for 20 minutes and then mix to form a water-based intermediate layer slurry;

[0060] A water-based intermediate layer slurry is coated on the inner side of the water-based dry surface layer. The water-based intermediate layer slurry is dried and solidified at a gradient temperature of 90 / 100 / 110 / 130 / 140°C to form a water-based intermediate layer with a thickness of 0.05 mm.

[0061] The following raw material components in parts by weight are weighed to prepare solvent-free A / B material resin slurry: 100 parts of polyether polyol resin CC6945 / 5310A; 125 parts of isocyanate resin AL-5040B; 0.04 parts of organic tin metal catalyst; 30 parts of calcium carbonate filler; the solvent-free A / B material resin slurry is evenly mixed and coated on the surface of the aqueous intermediate layer, and subjected to high-temperature reaction in an environment of 120° C. After the high-temperature reaction, it is compounded with high-density knitted imitation cotton lint by rollers, and then subjected to high-temperature online reaction at 140° C., and the release paper is peeled off after aging at room temperature to obtain water-based solvent-free vulcanized polyurethane synthetic leather for shoes; wherein: the high-density knitted imitation cotton lint is preheated before being laminated with the solvent-free A / B material resin slurry at high temperature, and the thickness of the formed solvent-free bonding layer is 0.40 mm.

[0062] Comparative Example 2

[0063] A method for preparing vulcanized polyurethane synthetic leather for shoes comprises the following steps:

[0064] The following raw material components by mass: 30 parts of polyester polyurethane resin JF-PDY-851MY, 30 parts of polyether sulfonic acid polyurethane resin 5215 70 parts, water-based color paste TSE LR01 10 parts, water-based crosslinking agent Impraifx R-7005 parts, water-based defoamer DF-2459 0.3 parts, water-based leveling agent LA-91-120 0.10 parts, water-based thickener ALA 1.0 parts, stir well in a stirring device for 20 minutes and then mix to form a water-based dry surface slurry;

[0065] Coat the release paper with water-based dry surface slurry, control the gradient temperature to 90 / 100 / 110 / 130 / 140°C for drying and curing, and the thickness of the formed water-based dry surface layer is 0.04mm;

[0066] The following raw material components in parts by weight: polyether sulfonic acid polyurethane resin 5215 20 parts, polyester sulfonic acid polyurethane resin JF-PDY-877HY 80 parts, water-based color paste TSE LR01 10 parts, water-based crosslinking agent Aquolin166 3 parts, water-based defoamer DF-2459 0.3 parts, water-based leveling agent LA-91-120 0.10 parts, water-based thickener ALA 1.0 parts, stir well in a stirring device for 20 minutes and then mix to form a water-based intermediate layer slurry;

[0067] A water-based intermediate layer slurry is coated on the inner side of the water-based dry surface layer. The water-based intermediate layer slurry is dried and solidified at a gradient temperature of 90 / 100 / 110 / 130 / 140°C to form a water-based intermediate layer with a thickness of 0.05 mm.

[0068] The following raw material components in parts by weight are weighed to prepare solvent-free A / B material resin slurry: 100 parts of polyether polyol resin CC6945 / 5310A; 125 parts of isocyanate resin AL-5040B; 0.02 parts of environmentally friendly amine catalyst CC 6945 / 92C-CC; 0.4 parts of environmentally friendly metal catalyst CC 6945 / 90C-CC; 30 parts of calcium carbonate filler; the solvent-free A / B material resin slurry is evenly mixed and coated on the surface of the aqueous intermediate layer, and a high-temperature reaction is carried out in an environment of 120° C. After the high-temperature reaction, it is compounded with high-density knitted imitation cotton lint by rollers, and then subjected to a high-temperature online reaction at 140° C., and the release paper is peeled off after aging at room temperature to obtain a water-based solvent-free vulcanized polyurethane synthetic leather for shoes; wherein: the high-density knitted imitation cotton lint is preheated before being laminated with the solvent-free A / B material resin slurry at high temperature, and the thickness of the formed solvent-free bonding layer is 0.40 mm.

[0069] After extensive research, polyurethane synthetic leather used for vulcanized shoes must basically have the product characteristics described in Table 2;

[0070] Table 2 Basic characteristics of vulcanized polyurethane synthetic leather for shoes

[0071]

[0072] Performance Testing:

[0073] The vulcanized polyurethane synthetic leather for shoes prepared in the above embodiments and comparative examples was subjected to performance tests, and the relevant performance test methods are as follows:

[0074] (1) Flexing resistance test: Flexing resistance is tested in accordance with ISO 5402-2002;

[0075] (2) Tensile strength: The tensile strength is tested according to ISO 13934-2, ASTM D5034;

[0076] (3) Tear strength: Tear strength is tested according to ASTM D2261 method / standard:

[0077] (4) Peel strength: Peel stiffness is tested according to GB / T 8949-2008 method / standard:

[0078] (5) Wear resistance (Martindale): Wear resistance test is carried out according to GB / T 19089-2003 method / standard

[0079] The measurement results of the vulcanized polyurethane synthetic leather for shoes prepared in Examples 1-3 and Comparative Example are shown in Table 3.

[0080] Table 3 Performance test results of vulcanized polyurethane synthetic leather for shoes prepared in Examples 1-3 and Comparative Examples

[0081]

[0082] It can be seen from the performance test results shown in Table 3 that the preparation technology of the present invention uses a fully aqueous solvent-free dry-paste process, which is green, environmentally friendly, and pollution-free, and the DMF in the finished product can be lower than 5ppm; the wet-process finished product selected for traditional vulcanized shoe leather has no strict control of restricted chemicals and DMF content, and cannot meet the increasingly stringent environmental protection requirements; therefore, the project design uses a water-based solvent-free technical solution, which strictly controls the raw materials and can fully meet the brand customers' requirements for the chemical control system of the product.

[0083] Due to the high performance requirements of vulcanized shoe leather, both the performance test standards of the product and the test standards of the finished shoes are very high. In order to achieve such high performance standards in a water-based solvent-free system, polyether polyol resins are selected for solvent-free polyurethane resins, and environmentally friendly amine and metal catalysts are selected instead of using the organic tin solvent-free catalysts currently on the market. The intermediate layer of sulfonic acid polyurethane resin is cross-linked and shaped after aging. After shaping and aging, it can withstand high-temperature processing to achieve the purpose of the whole shoe bending intact under high-temperature vulcanization conditions. The two-layer coating of the surface layer uses a suitable combination of different moduli to meet the high bending requirements of the surface products, which not only ensures the wear resistance of the product surface, but also has a high bonding strength with the bottom layer, making the product surface wear-resistant and scratch-resistant, and the overall formula has excellent yellowing resistance. In response to the problems of low adhesive strength, poor high-temperature vulcanization processing, decreased peel strength after vulcanization, and poor bending resistance of water-based solvent-free products, this patent uses 5215 and EX-RC-851MY have high temperature-resistant resin formulas. The softening point of the resin can reach above 180°C after adding the curing agent, and it can also have a peel strength of 2.0-3.0kgf / cm under the conditions of 120°C and 2h. The surface layer can be combined with the glue through chemical bonds and has good bonding strength with the sole. Through the water-based solvent-free process, the solvent-free online reaction has good peel strength and has high flex resistance after the shoe is manufactured.

[0084] Since consumer shoe leather products involve different areas of people's daily lives, patented products have the characteristics of multi-field and multi-functionality, with diverse colors, varied patterns, comfortable touch, scratch-resistant, wear-resistant, yellowing-resistant, and excellent bending resistance. At the same time, they meet customers' high-temperature processability and complex large-pattern requirements, are purely green and pollution-free, and can be used for a variety of high-performance, complex-shaped vulcanized shoes, leading the trend of fashion, innovation, and environmental protection.

[0085] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A vulcanized polyurethane synthetic leather for shoes, characterized in that: From the inside to the outside, it is composed of the imitation cotton velvet base fabric layer, the solvent-free adhesive layer, the water-based dry method middle layer and the water-based dry method surface layer, among which: The aqueous dry process intermediate layer is prepared from an aqueous dry process intermediate layer slurry, and the aqueous dry process intermediate layer slurry is prepared from the following components in parts by weight: The water-based dry surface layer is prepared from a water-based dry surface layer slurry, and the water-based dry surface layer slurry is prepared from the following components in parts by weight: The elastic modulus of the waterborne polyether sulfonic acid polyurethane resin is lower than 3 MPa, the elastic modulus of the waterborne polyester sulfonic acid polyurethane resin is greater than 6 MPa, and the elastic modulus of the waterborne polyester polyurethane resin is greater than 6 MPa.

2. The vulcanized polyurethane synthetic leather for shoes according to claim 1, characterized in that: The raw material of the imitation cotton velvet base fabric layer is a high-density knitted imitation cotton velvet base fabric with a gram weight of 230±10g / m 2 , thickness is 0.80±0.03mm.

3. The vulcanized polyurethane synthetic leather for shoes according to claim 1, characterized in that: The solvent-free adhesive layer is prepared by using solvent-free A / B material resin slurry, and the solvent-free A / B material resin slurry is prepared by the following components in parts by weight:

4. The method for preparing the vulcanized polyurethane synthetic leather for shoes according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Coating a water-based dry surface slurry on the release paper, and drying and curing under controlled gradient temperature to form a water-based dry surface layer; S2, coating the water-based intermediate layer slurry on the inner side of the water-based dry surface layer, controlling the gradient temperature to dry and solidify, and forming a water-based intermediate layer; S3, coating the solvent-free A / B material resin slurry on the aqueous intermediate layer, and after high-temperature reaction, compounding the high-density knitted imitation cotton flannel base cloth through rollers; and then after high-temperature online reaction, aging at room temperature, peeling off the release paper to obtain the final product.

5. The preparation method according to claim 4, characterized in that: In step S1, the gradient temperatures for controlling the gradient temperature drying and curing are: 90°C, 100°C, 110°C, 130°C, 140°C, and the thickness of the water-based dry surface layer is 0.04-0.06 mm.

6. The preparation method according to claim 4, characterized in that: In step S2, the gradient temperatures for controlling the gradient temperature drying and curing are: 90°C, 100°C, 110°C, 130°C, 140°C, and the thickness of the aqueous intermediate layer is 0.05-0.06 mm.

7. The preparation method according to claim 4, characterized in that: In step S3, the temperature of the high temperature reaction is 100-120°C, and the temperature of the high temperature online reaction is 130-140°C.

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