Cold-resistant synthetic leather for bags and handbags and preparation method of cold-resistant synthetic leather

Abstract

The invention provides cold-resistant synthetic leather for bags and handbags and a preparation method of the cold-resistant synthetic leather, the cold-resistant synthetic leather comprises a foaming layer and a dry-process veneering layer which are sequentially arranged from bottom to top, and the dry-process veneering layer comprises a dry-process inner layer and a dry-process outer layer which are sequentially arranged from bottom to top. The nano rubber particles with certain cold resistance and low hardness are selected as a foam stabilizer of the foaming layer and filler of the dry-process veneering layer, and the luggage and handbag leather prepared through design is not prone to stripping in a low-temperature environment and meanwhile has good cold resistance and wear resistance.

Description

Technical Field

[0001] The present invention relates to the field of synthetic leather, and in particular to cold-resistant synthetic leather for luggage and handbags and a preparation method thereof. Background Art

[0002] With the continuous development of science and technology, polyurethane synthetic leather has become one of the alternative materials to animal leather and has been widely used in luggage and handbags. However, in cold northern regions or in severe cold weather, luggage and handbag leather often loses its flexibility due to poor cold resistance, resulting in hardening, cracking or damage. Therefore, improving the cold resistance of polyurethane is crucial. Currently, the market adopts the method of modifying polyurethane raw materials to enhance the cold resistance of leather, but this increases the production cost of synthetic leather. In addition, some people choose to add cold-resistant agents to the polyurethane slurry, but this may cause the mechanical properties of polyurethane to deteriorate and fail to meet the wear resistance requirements of leather. Therefore, it is necessary to develop new methods to improve the cold resistance of leather to avoid these problems.

[0003] Due to the demand for softness, luggage and handbag leather typically incorporates a polyurethane foam layer as the inner layer. Uniform foaming of the polyurethane can improve its cold resistance to a certain extent. Compared to chemical foaming, mechanical agitation foaming reduces costs and environmental impact. However, a single agitation foaming process can easily cause slurry discharge, resulting in foam rupture and compromised leather performance. While the addition of solid nanoparticles can stabilize the foam, commonly used nanoparticles (such as nano-silica and nano-calcium carbonate) are relatively hard and have high surface energy, making them prone to self-aggregation around the foam, leading to foam rupture and uneven distribution, thus reducing the cold resistance of synthetic leather.

[0004] Furthermore, to meet usage requirements, luggage and handbag leather typically features a wear-resistant top layer. However, this highly wear-resistant top layer typically has poor cold resistance. If the cold resistance of the top layer differs significantly from that of the foam layer, the top layer may harden and separate from the foam layer in cold environments. How to ensure that the top layer is both wear-resistant and cold-resistant while also resisting separation from the foam layer remains an unresolved challenge in the luggage and handbag leather industry.

[0005] In view of the above problems, the present invention prepares a cold-resistant synthetic leather for luggage and handbags, which has good wear resistance and cold resistance. Summary of the Invention

[0006] In view of the above problems in the prior art, the present invention provides a cold-resistant synthetic leather for luggage and handbags and a preparation method thereof, which is not easy to peel off in a low temperature environment and has good cold resistance and wear resistance.

[0007] To achieve the above object, the present invention adopts the following technical solutions: The present invention provides a cold-resistant synthetic leather for luggage and handbags and a preparation method thereof. The cold-resistant synthetic leather for luggage and handbags comprises a foaming layer and a dry veneer layer arranged in sequence from bottom to top; The foaming layer comprises the following components in parts by weight: 5 to 7 parts of nano rubber particles, 80 to 95 parts of water-based soft polyurethane, 10 to 20 parts of water-based color paste, and 0.3 to 0.8 parts of thickener; The dry-process veneer layer includes a dry-process inner layer and a dry-process outer layer arranged in sequence from bottom to top, wherein the dry-process inner layer includes the following components in parts by weight: 80-90 parts of waterborne polyurethane resin, 0.02-0.01 parts of leveling agent, 0.05-0.2 parts of waterborne color paste, 0.1-0.3 parts of defoaming agent, 3-7 parts of cold-resistant agent and 5-10 parts of nano-rubber particles; the dry-process outer layer includes the following components in parts by weight: 80-90 parts of waterborne polyurethane resin, 0.02-0.1 parts of leveling agent, 0.05-0.2 parts of waterborne color paste, 0.1-0.3 parts of defoaming agent, 3-7 parts of cold-resistant agent and 15-25 parts of nano-rubber particles.

[0008] Preferably, the preparation of cold-resistant synthetic leather for luggage and handbags includes the following steps: (1) Soak the synthetic leather base fabric in the impregnation solution at 15-20°C for 20-40 minutes, then iron and dry it with an ironing roller at 125-135°C; (2) Adding nano rubber particles to water-based soft polyurethane, mechanically stirring the mixture at 400-600 rpm for 1-2 min, and mechanically stirring the mixture at 900-1100 rpm for 4-6 min, then adding water-based color paste and thickener, and mechanically stirring the mixture at 400-600 rpm for 1-2 min to obtain a foaming layer slurry, which is evenly coated on the pretreated base fabric with a scraping thickness of 1-2 mm, and dried at 80-100 °C for 10-20 min to obtain a foaming layer; (3) Adding nano rubber particles to waterborne polyurethane resin, mechanically stirring at 900-1100 rpm for 1-3 min, then adding leveling agent, waterborne color paste, defoaming agent and cold resistant agent, mechanically stirring at 400-600 rpm for 1-2 min, respectively, to prepare dry inner and outer layer slurries; scraping the dry outer layer slurry onto release paper by roller coating, with a coating thickness of 0.3-0.5 mm, drying at 80-100 ° C for 10-20 min to a semi-dry state, and cooling to obtain a dry outer layer; scraping the dry inner layer slurry onto the dry outer layer by roller coating, with a coating thickness of 1-1.5 mm, drying at 80-100 ° C for 5-15 min to a semi-dry state, and cooling to obtain a dry veneer layer; (4) The dry inner layer of the dry veneer layer is laminated to the foam layer and ironed with an ironing roller at 100-120°C for 1-2 minutes, followed by drying in an oven at 130-140°C for 10-20 minutes. After cooling, the release paper is peeled off, and then the finished leather is obtained by printing and embossing.

[0009] Preferably, the nano rubber particles in the foaming layer and the dry veneer layer are nitrile rubber nano powders with an acrylonitrile content of 25-27% and a particle size of 50-100 nm.

[0010] Preferably, the solid content of the water-based soft polyurethane resin in the foaming layer is 30-40%, the viscosity is 3000-5000 Pa·s, and the elongation at break is ≥500%; the water-based color paste is a commonly used water-based color paste in this field; and the thickener is a non-ionic water-based polyurethane thickener.

[0011] Preferably, the waterborne polyurethane resin in the dry veneer layer is a commonly used waterborne polyurethane resin in the art, more preferably a polycarbonate waterborne polyurethane resin; the leveling agent is a silicone leveling agent; the defoaming agent is a waterborne defoaming agent; and the cold-resistant agent is γ-butyrolactone.

[0012] Preferably, in step (1), the synthetic leather base fabric is a woven fabric or a knitted fabric, the hair effect on the back of the synthetic leather base fabric is hairless or slightly hairy, and the impregnation liquid is a 0.5-1% fluorine-free waterproofing agent, wherein the fluorine-free waterproofing agent is one of a silicone-based fluorine-free waterproofing agent, a fluorine-free water-based polyurethane waterproofing agent, and an acrylic ester-based fluorine-free water repellent.

[0013] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention selects nano rubber particles with certain cold resistance and low hardness as foam stabilizers. By designing the addition amount of nano rubber and combining it with a simple mechanical foaming method, the stability and uniformity of the foam during the foaming process are effectively improved, thereby improving the cold resistance of the foaming layer.

[0014] (2) The dry veneer layer of the present invention is divided into two layers, the inner and outer layers. Through the limited slurry composition design, the wear resistance of the dry veneer layer is gradually enhanced from the inner to the outer layer, effectively preventing the dry veneer layer from peeling off from the foam layer due to the decrease in cold resistance under low temperature conditions. In addition, the nano rubber itself has a certain degree of cold resistance, which further achieves a balance between cold resistance and wear resistance of the dry veneer layer.

[0015] Other advantages, objectives and features of the present invention will be reflected in part from the following description and will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] none DETAILED DESCRIPTION The present invention is described in detail below by way of examples, which are only used to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. It should be understood that after reading the contents of the present invention, those skilled in the art may make various changes or modifications to the present invention, and such equivalent forms also fall within the scope defined by the claims appended hereto.

[0017] Example 1 (1) Soak the synthetic leather woven fabric in 0.8% silicone-based fluorine-free waterproofing agent at 18°C for 30 minutes, then iron it with an ironing roller at 130°C and dry it; (2) 6 parts of nitrile rubber nanopowder were added to 90 parts of water-based soft polyurethane, and the mixture was mechanically stirred at 500 rpm for 2 minutes and at 1000 rpm for 5 minutes. Subsequently, 15 parts of water-based color paste and 0.5 parts of non-ionic water-based polyurethane thickener were added, and the mixture was mechanically stirred at 500 rpm for 2 minutes to prepare a foaming layer slurry, which was evenly coated on the pretreated base fabric with a scraping thickness of 1.5 mm and dried at 90°C for 15 minutes to prepare a foaming layer. (3) 7 parts of nitrile rubber nanopowder were added to 85 parts of polycarbonate type waterborne polyurethane resin, and mechanically stirred at 1000 rpm for 2 minutes, followed by adding 0.05 parts of silicone leveling agent, 0.1 parts of waterborne color paste, 0.2 parts of waterborne defoaming agent and 5 parts of γ-butyrolactone, and mechanically stirred at 500 rpm for 2 minutes to prepare dry inner layer slurry; 20 parts of nitrile rubber nanopowder were added to 85 parts of polycarbonate type waterborne polyurethane resin, and mechanically stirred at 1000 rpm for 2 minutes, and then added 0.05 parts of A silicone leveling agent, 0.1 parts of water-based color paste, 0.2 parts of water-based defoaming agent and 5 parts of γ-butyrolactone were mechanically stirred at 500 rpm for 2 minutes to prepare a dry outer layer slurry; the dry outer layer slurry was scraped onto the release paper by roller coating to a thickness of 0.4 mm, dried at 90°C for 15 minutes until semi-dry, and cooled to obtain a dry outer layer; then, the dry inner layer slurry was scraped onto the dry outer layer by roller coating to a thickness of 1.3 mm, dried at 90°C for 10 minutes until semi-dry, and cooled to obtain a dry veneer layer; (4) The dry inner layer of the dry veneer layer is laminated to the foam layer and ironed with an ironing roller at 110°C for 2 minutes, followed by drying in an oven at 135°C for 15 minutes. After cooling, the release paper is peeled off, and then the finished leather is obtained by printing and embossing.

[0018] Example 2 (1) Soak the synthetic leather knitted fabric in 0.5% fluorine-free water-based polyurethane waterproofing agent at 15°C for 40 minutes, then iron it with an ironing roller at 135°C and dry it; (2) 7 parts of nitrile rubber nanopowder were added to 80 parts of water-based soft polyurethane, and the mixture was mechanically stirred at 400 rpm for 1 min and at 900 rpm for 4 min. Subsequently, 10 parts of water-based color paste and 0.3 parts of non-ionic water-based polyurethane thickener were added, and the mixture was mechanically stirred at 400 rpm for 1 min to prepare a foaming layer slurry, which was evenly coated on the pretreated base fabric with a scraping thickness of 1 mm and dried at 80°C for 10 min to prepare a foaming layer. (3) Add 10 parts of nitrile rubber nanopowder to 80 parts of polycarbonate type waterborne polyurethane resin, stir mechanically at 900 rpm for 1 min, then add 0.02 parts of silicone leveling agent, 0.05 parts of waterborne color paste, 0.1 parts of waterborne defoamer and 3 parts of γ-butyrolactone, stir mechanically at 400 rpm for 1 min to prepare dry inner layer slurry; add 15 parts of nitrile rubber nanopowder to 80 parts of polycarbonate type waterborne polyurethane resin, stir mechanically at 900 rpm for 1 min, then add 0.02 parts of A silicone leveling agent, 0.05 parts of water-based color paste, 0.1 parts of water-based defoaming agent and 3 parts of γ-butyrolactone were mechanically stirred at 400 rpm for 1 minute to prepare a dry outer layer slurry; the dry outer layer slurry was scraped onto the release paper by roller coating to a thickness of 0.3 mm, dried at 80°C for 10 minutes until semi-dry, and cooled to obtain a dry outer layer; then, the dry inner layer slurry was scraped onto the dry outer layer by roller coating to a thickness of 1.5 mm, dried at 80°C for 5 minutes until semi-dry, and cooled to obtain a dry veneer layer; (4) The dry inner layer of the dry veneer layer is laminated to the foam layer and ironed with an ironing roller at 100°C for 1 minute, followed by drying in an oven at 130°C for 10 minutes. After cooling, the release paper is peeled off, and then the finished leather is obtained by printing and embossing.

[0019] Example 3 (1) Soak the synthetic leather woven fabric in 1% acrylic fluorine-free water repellent at 20°C for 20 minutes, then iron it with an ironing roller at 135°C and dry it; (2) Add 5 parts of nitrile rubber nanopowder to 95 parts of water-based soft polyurethane, mix and mechanically stir at 600 rpm for 2 minutes, and mechanically stir at 1100 rpm for 6 minutes, then add 20 parts of water-based color paste and 0.8 parts of non-ionic water-based polyurethane thickener, and mechanically stir at 600 rpm for 2 minutes to prepare a foaming layer slurry, which is evenly coated on the pretreated base fabric with a scraping thickness of 2 mm, and dried at 100 ° C for 20 minutes to prepare a foaming layer; (3) Add 5 parts of nitrile rubber nanopowder to 90 parts of polycarbonate type waterborne polyurethane resin, stir mechanically at 1100 rpm for 3 minutes, then add 0.1 parts of silicone leveling agent, 0.2 parts of waterborne color paste, 0.3 parts of waterborne defoaming agent and 7 parts of γ-butyrolactone, stir mechanically at 600 rpm for 2 minutes to prepare dry inner layer slurry; add 25 parts of nitrile rubber nanopowder to 90 parts of polycarbonate type waterborne polyurethane resin, stir mechanically at 1100 rpm for 3 minutes, then add 0.1 parts of organic solvent. A silicone leveling agent, 0.2 parts of water-based color paste, 0.3 parts of water-based defoaming agent and 7 parts of gamma-butyrolactone were mechanically stirred at 600 rpm for 2 minutes to prepare a dry outer layer slurry; the dry outer layer slurry was scraped onto the release paper by roller coating to a thickness of 0.5 mm, dried at 100°C for 20 minutes until semi-dry, and cooled to obtain a dry outer layer; then, the dry inner layer slurry was scraped onto the dry outer layer by roller coating to a thickness of 1 mm, dried at 100°C for 15 minutes until semi-dry, and cooled to obtain a dry veneer layer; (4) The dry inner layer of the dry veneer layer is laminated to the foam layer and ironed with an ironing roller at 120°C for 2 minutes, followed by drying in an oven at 140°C for 20 minutes. After cooling, the release paper is peeled off, and then the finished leather is obtained by printing and embossing.

[0020] Comparative Example 1 The cold-resistant synthetic leather for luggage and handbags is different from Example 1 only in that nano-silicon dioxide particles are added instead of nitrile rubber nanopowder during the preparation of the foaming layer, and the remaining preparation steps are the same as Example 1.

[0021] Comparative Example 2 The cold-resistant synthetic leather for luggage and handbags is different from Example 1 only in that nano-silicon dioxide particles are added instead of nitrile rubber nanopowder during the preparation of the dry inner and outer layers. The remaining preparation steps are the same as Example 1.

[0022] Comparative Example 3 The cold-resistant synthetic leather for luggage and handbags is different from that of Example 1 only in that the dry inner layer is replaced by a dry outer layer of the same thickness during the preparation of the dry veneer layer, and the remaining preparation steps are the same as those of Example 1.

[0023] Test methods and results 1. Glass transition temperature (Tg): The glass transition temperature (Tg) of the samples was measured using a TA Q200 thermogravimetric analyzer from the United States. Nitrogen protection was used, the sample mass was 5-10 mg, the heating rate was 10°C / min, and the temperature range was -70-100°C.

[0024] 2. Low-Temperature Impact: Refer to GB / T 38465-2020 standard, and perform low-temperature impact testing on samples using a low-temperature impact tester, set at -20°C or -30°C. Note: Low-temperature impact resistance: Grades 1 to 5 range from poor to excellent. Grade 1 is very poor, with synthetic leather breaking at -20°C; Grades 3 or higher are qualified, with synthetic leather showing no cracks at -20°C and severe cracks at -30°C; and Grade 5 is very good, with synthetic leather showing no cracks at -30°C.

[0025] 3. Mechanical properties: Refer to GB / T 8949-2008 standard and use an electronic universal material testing machine to test the tensile strength and elongation at break of the samples.

[0026] 4. Peel Strength: Peel strength tests were conducted on samples using an MXL-5 tensile testing machine in accordance with GB / T 8949-2008. The tensile rate was set to 100 mm / min. The peel strength between the foam layer and the dry-process veneer layer was tested five times at -20°C, and the average value was taken.

[0027] 5. Wear resistance: With reference to QB / T 2726-2005 standard, use MK-5135 Taber abrasion tester, select H-18 grinding head, 1000g weight, set the rotation speed to 2000 or 3000 rpm to test the wear resistance of the samples.

[0028] 6. Softness: Refer to GB / T 39371-2020 standard and use a softness tester to test the softness of samples at -20°C.

[0029] The test results are shown in Tables 1 to 3.

[0030] Table 1 Low temperature impact test results of the foam layer of Examples 1 to 3 and Comparative Examples 1 and 2 Table 1 shows the low-temperature impact test results of the foamed layers of Examples 1-3 and Comparative Examples 1 and 2. The results show that the foamed layers of Examples 1-3 and Comparative Example 2 have good cold resistance, reaching a low-temperature impact rating of 5, meaning they are crack-free at -30°C. This is presumably because the foamed layers of Examples 1-3 and Comparative Example 2 contain nano-rubber, which has a certain degree of cold resistance, as a foam stabilizer. Due to its soft material and low surface energy, the agglomeration force between the particles is weak, allowing them to better adhere to the gas-liquid interface of the foaming slurry, inhibiting slurry discharge and bubble aggregation, improving the stability and uniformity of the foam, and thus increasing the cold resistance of the foamed layer. Comparative Example 1, on the other hand, only achieved a low-temperature impact rating of 3. Although it showed no cracks at -20°C, it exhibited severe cracking at -30°C. This is likely because the nano-silica particles have a high hardness and high surface energy, which easily form large particle aggregates around each bubble, reducing foam stability and ultimately affecting the cold resistance of the foamed layer. Therefore, the foamed layer prepared by the present invention has good cold resistance.

[0031] Table 2 Test results of various properties of dry veneer layer in Examples 1 to 3 and Comparative Example 2 Table 2 shows the performance test results of the dry-process veneer layers of Examples 1-3 and Comparative Example 2. The lower the glass transition temperature, the better the cold resistance of the sample. By observing the glass transition temperature and low-temperature impact test results of each example and comparative example in the table, Examples 1-3 exhibit relatively good cold resistance, presumably due to the added nano-rubber particles' moderate cold resistance. Furthermore, the data in the table shows that the dry-process inner layers of Examples 1-3 exhibit lower glass transition temperatures than the dry-process outer layers, and their low-temperature impact test results reach level 5, indicating that the dry-process inner layers exhibit relatively good cold resistance, comparable to the foamed layer. In addition, the wear resistance test results show that the dry-process inner layer of Examples 1 to 3 showed no obvious surface wear after 2000 revolutions, and showed some wear at 3000 revolutions. The dry-process outer layer of Examples 1 to 3 and the dry-process inner and outer layers of Comparative Example 2 showed no obvious surface wear after 3000 revolutions, indicating that the wear resistance of the dry-process veneer layer of Examples 1 to 3 gradually increases from the inside to the outside. Compared with nano-silicon dioxide, the addition of nano-rubber does not affect the wear resistance of the dry-process outer layer, and can still meet the wear resistance requirements of the synthetic leather surface layer. In summary, the dry-process veneer layer designed in a limited manner in the present invention has good cold resistance and wear resistance.

[0032] Table 3 Test results of various properties of synthetic leather in Examples 1 to 3 and Comparative Examples 1 to 3 Table 3 shows the test results for various properties of the synthetic leathers of Examples 1-3 and Comparative Examples 1-3. Compared to Comparative Examples 1-3, Examples 1-3 exhibited greater tensile strength and elongation at break, demonstrating the superior flexibility of the luggage leathers prepared according to the present invention. Compared to Comparative Examples 1-3, Examples 1-3 achieved a low-temperature impact energy rating of Level 5 and exhibited excellent softness at -20°C, demonstrating the superior cold resistance of the luggage leathers prepared according to the present invention. Furthermore, compared to Comparative Examples 2 and 3, the peel strength of the foam layer and dry-process veneer layer of Examples 1-3 at -20°C was greater. This, combined with Tables 1 and 2, demonstrates that increased wear resistance of the dry-process veneer layer can affect its adhesion to the foam layer at low temperatures. Specifically, in Comparative Examples 2 and 3, while the wear resistance of the dry-process veneer layer increased, its cold resistance decreased. This resulted in a certain difference in cold resistance between the surface layer and the foam layer (different low-temperature impact ratings), leading to a poor peel resistance at -20°C for both layers. Similarly, the cold resistance of Comparative Example 3 is better than that of Comparative Example 2, and thus the peel strength between the surface layer and the foam layer of Comparative Example 3 is greater. Therefore, the luggage leather prepared by the present invention has good flexibility and both good cold resistance and wear resistance.

[0033] The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent replacements, or modifications based on the present invention to solve substantially the same technical problems and achieve substantially the same technical effects are all included in the scope of protection of the present invention.

Claims

1. A cold-resistant synthetic leather for bags and handbags and a preparation method thereof, wherein the cold-resistant synthetic leather for bags and handbags comprises a foaming layer and a dry-process veneer layer arranged in sequence from bottom to top; The foaming layer comprises the following components in parts by weight: 5 to 7 parts of nano rubber particles, 80 to 95 parts of water-based soft polyurethane, 10 to 20 parts of water-based color paste, and 0.3 to 0.8 parts of thickener; The dry veneer layer includes a dry inner layer and a dry outer layer arranged in sequence from bottom to top, wherein: The dry process inner layer includes the following components in parts by weight: 80-90 parts of waterborne polyurethane resin, 0.02-0.1 parts of leveling agent, 0.05-0.2 parts of waterborne color paste, 0.1-0.3 parts of defoaming agent, 3-7 parts of cold-resistant agent and 5-10 parts of nano rubber particles; the dry process outer layer includes the following components in parts by weight: 80-90 parts of waterborne polyurethane resin, 0.02-0.1 parts of leveling agent, 0.05-0.2 parts of waterborne color paste, 0.1-0.3 parts of defoaming agent, 3-7 parts of cold-resistant agent and 15-25 parts of nano rubber particles.

2. The cold-resistant synthetic leather for luggage and handbags and the preparation method thereof according to claim 1, characterized in that: The preparation includes the following steps: (1) Soak the synthetic leather base fabric in the impregnation solution at 15-20°C for 20-40 minutes, then iron and dry it with an ironing roller at 125-135°C; (2) Adding nano rubber particles to water-based soft polyurethane, mechanically stirring the mixture at 400-600 rpm for 1-2 min, and mechanically stirring the mixture at 900-1100 rpm for 4-6 min, then adding water-based color paste and thickener, and mechanically stirring the mixture at 400-600 rpm for 1-2 min to obtain a foaming layer slurry, which is evenly coated on the pretreated base fabric with a scraping thickness of 1-2 mm, and dried at 80-100 °C for 10-20 min to obtain a foaming layer; (3) Adding nano rubber particles to waterborne polyurethane resin, mechanically stirring at 900-1100 rpm for 1-3 min, then adding leveling agent, waterborne color paste, defoaming agent and cold resistant agent, mechanically stirring at 400-600 rpm for 1-2 min, respectively, to prepare dry inner and outer layer slurries; scraping the dry outer layer slurry onto release paper by roller coating, with a coating thickness of 0.3-0.5 mm, drying at 80-100 ° C for 10-20 min to a semi-dry state, and cooling to obtain a dry outer layer; scraping the dry inner layer slurry onto the dry outer layer by roller coating, with a coating thickness of 1-1.5 mm, drying at 80-100 ° C for 5-15 min to a semi-dry state, and cooling to obtain a dry veneer layer; (4) The dry inner layer of the dry veneer layer is laminated to the foam layer and ironed with an ironing roller at 100-120°C for 1-2 minutes, followed by drying in an oven at 130-140°C for 10-20 minutes. After cooling, the release paper is peeled off, and then the finished leather is obtained by printing and embossing.

3. The cold-resistant synthetic leather for luggage and handbags and the preparation method thereof according to claim 1, characterized in that: The nano rubber particles in the foaming layer and the dry veneer layer are nitrile rubber nano powders with an acrylonitrile content of 25-27% and a particle size of 50-100 nm.

4. The cold-resistant synthetic leather for luggage and handbags and the preparation method thereof according to claim 1, characterized in that: The solid content of the water-based soft polyurethane resin in the foaming layer is 30-40%, the viscosity is 3000-5000 Pa·s, and the elongation at break is ≥500%; the thickener is a non-ionic water-based polyurethane thickener.

5. The cold-resistant synthetic leather for luggage and handbags and the preparation method thereof according to claim 1, characterized in that: The leveling agent in the dry veneer layer is an organic silicon leveling agent; the defoaming agent is a water-based defoaming agent; and the cold-resistant agent is gamma-butyrolactone.

6. The cold-resistant synthetic leather for luggage and handbags and the preparation method thereof according to claim 2, characterized in that: In the step (1), the synthetic leather base fabric is a woven fabric or a knitted fabric, the back of which has a hairless or slightly hairy state, and the impregnation liquid is a 0.5-1% fluorine-free waterproofing agent, wherein the fluorine-free waterproofing agent is one of a silicone-based fluorine-free waterproofing agent, a fluorine-free water-based polyurethane waterproofing agent, and an acrylic ester-based fluorine-free water repellent.

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