A method for producing light and thin composite synthetic leather

Abstract

The present invention provides a method for producing light and thin composite synthetic leather, wherein the synthetic leather includes a space leather layer and a hot melt adhesive layer compounded on the back of the space leather layer; the production method includes selecting a suitable non-woven fabric, impregnating the non-woven fabric with PVA, adding an appropriate amount of softener, and obtaining a base fabric; unwinding the base fabric for impregnation, pre-solidification, and ironing, and then using a coating device to scrape the configured fabric onto the surface of the base fabric; sending the coated base fabric into a second coagulation tank for coagulation, a water washing tank for washing, a heating roller for heating, an oven for drying, a cooling roller for cooling, and winding to obtain a space leather layer; compounding a hot melt adhesive layer on the back of the space leather layer, and controlling the temperature during compounding at 150±1°C to obtain synthetic leather. The obtained product has strong processability, is light and thin, and has an overall gram weight of ≦230g / m 2 , truly lightweight, with a softness test value between 2.2-2.6; and while being overall light and thin, it can still maintain high tear strength, with a tear strength of up to 70N / 3cm.

Description

Technical field

[0001] The invention relates to the technical field of synthetic leather, and in particular to a method for producing light and thin composite synthetic leather. [Background Technology]

[0002] At present, synthetic leather products are used in all aspects of our lives, and the types and applications of their products are also rich and colorful.

[0003] TPU, with its excellent performance, is often used in shoes and shoe soles. However, traditional TPU shoemaking processes have certain limitations, such as limitations in grain and embossing. To overcome these limitations, we conducted research and experiments to address this issue.

[0004] First, a thin, lightweight, high-performance space leather was developed, and then 0.15mm hot melt adhesive was used for back lamination. The advantage of this product is that the surface can be developed with a variety of texture effects. The difficulties in this development are:

[0005] ① When producing light and thin space leather with high physical properties, the thickness of the product needs to be controlled at 0.55-0.65mm, the weight is below 230g / m2, and the tear strength is >65N / 3cm. How to solve the problem of excessive slurry penetration during production, resulting in high weight and ensuring qualified physical properties is a difficult point.

[0006] ②How to improve the composite strength between hot melt adhesive and the back of space leather. [Summary of the invention]

[0007] The present invention aims to solve the technical problems of excessive slurry penetration leading to high gram weight during the production of space leather, and how to improve the composite strength of space leather and hot melt adhesive. To address this problem, this case selects a suitable non-woven fabric, treats the non-woven fabric with PVA powder and adds a softener to make the required base fabric, and adjusts the machine process and the selection and combination of coating resins. Through a series of experimental improvements, a method for producing a thin and light composite synthetic leather with strong processability has been developed.

[0008] The present invention is achieved as follows: a method for producing a light and thin composite synthetic leather, wherein the synthetic leather comprises a space leather layer and a hot melt adhesive layer composited on the back of the space leather layer;

[0009] The production method comprises the following steps:

[0010] (1) Select a suitable non-woven fabric, impregnate the non-woven fabric with PVA, add an appropriate amount of softener, obtain the required base fabric, and roll it up;

[0011] (2) unwinding the base fabric into an impregnation tank for impregnation;

[0012] (3) sending the base fabric into a pre-coagulation tank for pre-coagulation, ironing the pre-coagulated base fabric, and then using a coating device to scrape the prepared fabric onto the surface of the base fabric;

[0013] (4) The coated base fabric is sequentially sent to the second coagulation tank for coagulation, washed in a water washing tank, heated by a heating roller, dried in an oven, cooled by a cooling roller, and rolled up to obtain a space leather layer;

[0014] (5) Compounding a hot melt adhesive layer on the back of the space leather layer, controlling the temperature during compounding at 150±1°C, to obtain synthetic leather.

[0015] Furthermore, in step (1), the thickness of the non-woven fabric is controlled to be 0.35-0.45 mm, and the weight is 120 g / m 2 , blasting is 14kgf / cm 2 , tensile strength in warp and weft directions>200N / 3cm, elongation at break in warp direction 30-90%, elongation at break in weft direction 50-150%, tear strength in warp and weft directions>60N / 3cm, nylon content is 70%.

[0016] Furthermore, in step (1), when the non-woven fabric is impregnated with PVA, PVA powder and water are first mixed evenly in a ratio of 3:100, the temperature is controlled at 90-95° C., and after complete mixing and dissolution, an appropriate amount of softener is added.

[0017] Furthermore, in step (2), the formula of the impregnation material in the impregnation tank includes impregnation resin, dimethylformamide, anti-tear aid, hydrolysis resistance aid, and color paste; the ratio of the impregnation resin, dimethylformamide, anti-tear aid, hydrolysis resistance aid, and color paste is 100:260:(5-10):2:15; the prepared impregnation liquid is stirred at room temperature at a stirring speed of 1000-1500r / min for 15-20 minutes until it is completely dissolved, and the viscosity of the impregnation material is controlled at 200-260cps.

[0018] Furthermore, the impregnation resin has a solid content of 30%, a 100% modulus of 20-30 kgf / cm, and a softening point of 140°C.

[0019] Furthermore, in step (3), the pressure of the hydraulic roller in the pre-coagulation tank is controlled to be 5-5.5 kg, and the sugar content of the pre-coagulation liquid in the pre-coagulation tank is 30-32%.

[0020] Furthermore, in step (3), the coating device controls the thickness of the coating by adjusting the gap between the coating knives, the coating gap is controlled between 90±5 silk, and the coating amount is 0.95±0.05kg / y.

[0021] Furthermore, in step (3), the fabric formula includes resin A, resin B, dimethylformamide, nonionic surfactant, hydrolysis-resistant additive, filler, and color paste; the ratio of resin A, resin B, dimethylformamide, nonionic surfactant, hydrolysis-resistant additive, filler, and color paste is (20-40): (60-80): 40: 0.5: 1: 1: 3;

[0022] The resin A has a solid content of 35%, a 100% modulus of 25-35 kgf / cm, a tensile strength of >40 MPa, and an elongation of ≥400%.

[0023] The resin B has a solid content of 35%, a 100% modulus of 80-90 kgf / cm, a tensile strength of >45 MPa, and an elongation of ≥350%;

[0024] The prepared fabric is stirred at a high speed of 1000-1500 r / min at room temperature for 30-35 minutes until it is completely and evenly dissolved, and the stirring speed is reduced to 300±50 r / min, and vacuum degassing is performed for 90 minutes. The viscosity of the fabric is controlled at 16000-17000 cps.

[0025] Furthermore, in step (4), the coagulation sugar content in the second coagulation tank is 17-21%, and the temperature is controlled at 30±2°C; after the coated base fabric comes out of the second coagulation tank, the surface of the synthetic leather is observed, and the thickness and width are measured. The thickness is controlled to be between 0.6-0.65mm, and the width is between 1.47-1.49m;

[0026] The water washing tanks include 15 groups of water washing tanks. The sugar content of the first six groups is controlled at 20-10%, the sugar content of the middle six groups is controlled at 10-0%, and the sugar content of the last three groups is 0%. The water washing temperature of the last three groups is controlled at 60±5℃.

[0027] The ovens include five groups, the oven temperature of the first group is 160° C., the oven temperature of the second to fourth groups is 170° C., and the oven temperature of the fifth group is 160° C. until the products are completely dried.

[0028] Furthermore, in step (5), the thickness of the hot melt adhesive layer is controlled to be 0.15-0.20 mm.

[0029] The advantages of the present invention are:

[0030] 1. The resin used in the fabric does not contain fluorine compounds, which meets environmental protection requirements.

[0031] 2. The method for producing light and thin composite synthetic leather of the present invention overcomes the limitations of traditional TPU shoemaking technology. The product produced has strong processability, is light and thin, and has an overall weight of ≦230g / m 2, truly lightweight, with a softness test value between 2.2-2.6; and while being overall light and thin, it can still maintain high tear strength, with a tear strength of up to 70N / 3cm.

[0032] 3. The composite strength of the light and thin space leather and the hot melt adhesive layer of the present invention is high.

Brief Description of the Drawings

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0034] Figure 1 It is a schematic structural diagram of the light and thin composite synthetic leather of the present invention.

[0035] Figure 2 It is a schematic diagram of the preparation principle of the base fabric in the present invention.

[0036] Figure 3 It is a schematic diagram of the preparation principle of the space leather layer in the present invention.

[0037] Space leather layer 1, base fabric 11, fabric 12, hot melt adhesive layer 2, non-woven fabric A, impregnation tank 3, pre-coagulation tank 4, coating device 5, second coagulation tank 6, washing tank 7, oven drying 8. [Specific implementation method]

[0038] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention for which protection is sought, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0039] The present invention provides a method for producing a light and thin composite synthetic leather. The synthetic leather comprises a space leather layer 1 and a hot melt adhesive layer 2 composited on the back of the space leather layer 1.

[0040] The method for producing light and thin composite synthetic leather comprises the following steps:

[0041] (1) Select a suitable non-woven fabric, impregnate the non-woven fabric with PVA (polyvinyl alcohol), add an appropriate amount of softener, obtain the required base fabric 11, and roll up the base fabric 11.

[0042] (2) unwinding the base fabric 11 into the impregnation tank 3 for impregnation;

[0043] (3) The base fabric 11 is fed into the pre-coagulation tank 4 for pre-coagulation, the pre-coagulated base fabric 11 is then ironed, and the prepared fabric 12 is then scraped onto the surface of the base fabric 11 using the coating device 5;

[0044] (4) The base fabric 11 coated with the fabric 12 is sequentially sent to 6 for coagulation, washed in a water washing tank 7, heated by a heating roller, dried in an oven 8, cooled by a cooling roller, and rolled up to obtain a space leather layer;

[0045] (5) Compounding a hot melt adhesive layer on the back of the space leather layer, controlling the temperature during compounding at 150±1°C, to obtain synthetic leather.

[0046] In step (1), non-woven fabric A produced by Jiangsu Shenlong Non-woven Fabric Co., Ltd. is selected. The thickness of non-woven fabric A is controlled at 0.35-0.45 mm and the weight is 120 g / m 2 , blasting is 14kgf / cm 2 , tensile strength in warp and weft directions>200N / 3cm, elongation at break in warp direction 30-90%, elongation at break in weft direction 50-150%, tear strength in warp and weft directions>60N / 3cm, nylon content is 70%.

[0047] The weight of non-woven fabric A meets the requirements and has few surface burrs. However, since the weight of non-woven fabric A is 120g / m 2 Because non-woven fabric A has a lower weight, the slurry easily penetrates excessively during production, resulting in a higher weight for the base fabric. To address this issue and ensure both good feel and good weight, non-woven fabric A was first impregnated with PVA (polyvinyl alcohol). The ratio of PVA powder to water was 3:100. To ensure the overall softness of non-woven fabric A, an appropriate amount of softener was added to the original PVA powder ratio. This PVA treatment slows the penetration of slurry, preventing a higher weight and maintaining the proper physical properties of non-woven fabric A.

[0048] In step (1), when treating the PVA (polyvinyl alcohol) base fabric, first mix the PVA powder and water in a large tank at a ratio of 3:100 and evenly stir them. The temperature is controlled at 90-95°C. After they are completely mixed and dissolved, an appropriate amount of softener is added. After testing different ratios of PVA powder and water, when the ratio is 4:100, the base fabric penetration effect will be poor, which will affect the gram weight and feel, and will not meet the product requirements. When the ratio is 2:100, the base fabric penetration effect is still good, but it also affects the gram weight and feel, and will not meet the product requirements. Finally, it was determined that the ratio of PVA powder and water is 3:100, which meets the product requirements.

[0049] In step (1), in order to improve the feel and tear strength of the subsequent product, an appropriate amount of softener is added to adjust the softness. Through comparative tests, when no softener is added, the softness value of the product is between 2.3-2.4. After adding softener, the softness value of the product can reach 2.6. By adding softener, the product quality is improved to a certain extent and meets the product requirements.

[0050] In step (2), when unwinding, the base cloth 11 first passes through the cloth storage rack at a speed of 15 m / min, and then passes through the impregnation tank 3. The pressure of the impregnation oil pressure roller in the impregnation tank 3 is controlled at 5-5.5 kg.

[0051] The formula of the impregnation material in the impregnation tank 3 includes impregnation resin, dimethylformamide, anti-tear aid, hydrolysis resistance aid, and color paste; the ratio of the impregnation resin, dimethylformamide, anti-tear aid, hydrolysis resistance aid, and color paste is 100:260:(5~10):2:15.

[0052] The impregnation resin used is the hydrolysis-resistant impregnation resin XCW-30DP produced by Asahikawa Corporation. The solid content of the hydrolysis-resistant impregnation resin is 30%, the 100% modulus is 20-30kgf / cm, and the softening point is 140°C. The hydrolysis-resistant impregnation resin solidifies slowly in a dimethylformamide (DMF) aqueous solution, consumes a large amount of material, and the folds are relatively fine. In order to ensure the fastness and stability of the subsequent composite hot melt adhesive on the back of each layer of the space, the hydrolysis-resistant impregnation resin has lowered its softening point (from 170°C to 140°C) on the original basis, and the overall solidification speed has decreased. The softening point temperature is higher than 140°C, and the solidification speed is too fast.

[0053] The tear-resistant additive used is 08WH additive produced by Asahikawa Company, which is used to improve the overall tear strength of the base fabric.

[0054] The hydrolysis-resistant additive used is 121 additive produced by Yisan Company, and its main function is to improve the hydrolysis resistance of the base fabric.

[0055] The amount of color paste added can be adjusted according to different color requirements.

[0056] The preparation process of the impregnated material comprises the following steps:

[0057] The prepared impregnation liquid is stirred at room temperature at a stirring speed of 1000-1500 r / min for 15-20 minutes until all materials are completely dissolved. The viscosity of the impregnation material is controlled at 200-260 cps.

[0058] In step (3), the pressure of the hydraulic roller in the pre-coagulation tank 4 is controlled at 5-5.5 kg, and the sugar content of the pre-coagulation liquid in the pre-coagulation tank 4 is 30-32% (the sugar content is the DMF concentration in the DMF aqueous solution, which is measured by Abbe refractometer. The following sugar content is obtained from this). The pressure of the hydraulic roller in the pre-coagulation tank 4 is also controlled at 5-5.5 kg.

[0059] The coating device 5 controls the coating thickness by adjusting the gap between the coating blades. It is used to scrape the prepared fabric 12 onto the base fabric 11, achieving properties such as easy peeling, high support, and skin-friendliness. The coating device 5 includes a coating blade that scrapes the fabric 12 onto the base fabric 11 as it passes through the coating device 5. To ensure a consistent coating thickness, the gap between the coating blade and the base fabric 11 is set at 90 ± 5 mm, and the coating rate is 0.95 ± 0.05 kg / yr.

[0060] The formula of the fabric 12 includes resin A, resin B, dimethylformamide, nonionic surfactant, hydrolysis-resistant additive, filler, and color paste; the ratio of resin A, resin B, dimethylformamide, nonionic surfactant, hydrolysis-resistant additive, filler, and color paste is (20-40): (60-80): 40: 0.5: 1: 1: 3.

[0061] The resin A has a solid content of 35%, a 100% modulus of 25-35 kgf / cm, a tensile strength greater than 40 MPa, and an elongation greater than or equal to 400%.

[0062] The resin B has a solid content of 35%, a 100% modulus of 80-90 kgf / cm, a tensile strength greater than 45 MPa, and an elongation greater than or equal to 350%.

[0063] Fabric 12 utilizes a combination of two hydrolysis-resistant polyurethane resins (Resin A and Resin B) manufactured by Asahikawa. These resins offer excellent resilience and high peel strength, and are fluorine-free, meeting environmental requirements. The combination of two resins with different moduli allows for greater flexibility in adjusting the hand feel.

[0064] The non-ionic surfactant is S-7 additive produced by Shanghai Riduo Company, which is mainly used to adjust the arrangement of bubbles and improve the water washing effect of the base fabric to a certain extent.

[0065] The hydrolysis resistance additive is 121 additive produced by No. 13 Company, and its main function is to improve the hydrolysis resistance.

[0066] The filler is HFD-780 wood flour, which mainly plays a certain fluffy role and can reduce the gram weight per unit volume to a certain extent.

[0067] Without adding filler, the overall weight of the base fabric is closer to the upper limit (the upper limit is 230g / m 2 ), the gram weight is between 220-240g, which cannot achieve the characteristic of being light and thin, so fillers are added to the fabric 12 to reduce the gram weight of the fabric 12.

[0068] The amount of color paste added can be adjusted according to different color requirements.

[0069] The configuration process of the fabric 12 includes the following steps: stirring the prepared fabric 12 at a high speed of 1000-1500 r / min for 30-35 minutes at room temperature. The high-speed stirring time of the fabric 12 is strictly controlled between 30-35 minutes. If the time is too short, the slurry may not be fully stirred. If the time is too long, the material temperature will be too high, resulting in dead material. Stir until various materials are completely and evenly dissolved, reduce the stirring speed to 300±50 r / min, and perform vacuum degassing for 90 minutes. The viscosity of the fabric 12 is controlled at 16000-17000 cps.

[0070] In step (4), the second coagulation tank 6 contains a coagulation liquid with a coagulation sugar content of 17-21% and a temperature controlled at 30±2°C; the second coagulation tank 6 is used to coagulate the bonded fabric 12 so that the fabric 12 penetrates into the base fabric 11.

[0071] Traditionally, a single-layer coagulation tank is usually used, which can meet the requirement that the base fabric 11 achieves penetration after pre-solidification. However, when using a single-layer coagulation tank, the coagulation speed is relatively fast, which causes the bubbles to increase accordingly, which has a certain impact on the peeling strength. The second coagulation tank 6 of the present invention has a coagulation oil pressure roller that realizes three folds from bottom to top. The coagulation oil pressure roller is used to press the fabric 12 into the second coagulation tank 6 for coagulation. There are two coagulation oil pressure rollers at both ends of the second coagulation tank 6, and the coagulation oil pressure rollers at both ends are staggered with each other, so that the surface layer can realize three folds from bottom to top in the second coagulation tank 6, so that the fabric 12 is more fully coagulated and the bubbles are finer; it can not only meet the penetration problem of the base fabric 11, but also solve the peeling strength problem through the second coagulation tank 6.

[0072] In order to make the fabric 12 coagulate more fully and ensure that the fabric 12 is fully permeated, the length of the second coagulation tank 6 is 30m.

[0073] After the coated surface layer base fabric 11 comes out of the second coagulation tank 6, the surface condition of the synthetic leather is observed, and the thickness and width are measured. The thickness is controlled between 0.6-0.65 mm and the width is between 1.47-1.49 mm.

[0074] The washing tank 7 includes 15 groups of washing tanks 7, the sugar content of the first six groups is controlled at 20-10%, the sugar content of the middle six groups is controlled at 10-0%, the sugar content of the last three groups is 0%, and the washing temperature of the last three groups is controlled at 60±5℃.

[0075] The oven 8 includes five groups. The temperature of the oven 8 of the first group is 160°C, the temperature of the oven 8 of the second to fourth groups is 170°C, and the temperature of the oven 8 of the fifth group is 160°C. Until it is completely dried, the required space leather layer is obtained. The three-centimeter peeling test shows that it can reach 100N / 3cm, the softness test value is between 2.2-2.6, and the gram weight is 210-230g / m 2 , tear strength ≧70N / 3CM.

[0076] In step (5), the thickness of the hot melt adhesive layer is controlled at 0.15-0.20mm. When laminating with the back of the space leather layer, the laminating temperature must be strictly controlled. After multiple tests, when the laminating temperature is higher than 155°C, there will be a risk of glue overflow and sticking; when the temperature is lower than 145°C, the hot melt adhesive is likely to have insufficient adhesion to the back of the space leather layer. It was finally determined that the laminating temperature is 150±1°C and the vehicle speed is controlled at 1 yard / minute, which can meet the laminating requirements.

[0077] A number of experiments were conducted using the method for producing light and thin composite synthetic leather of the present invention. Several examples and comparative examples are selected below to further illustrate the beneficial effects of the method for producing light and thin composite synthetic leather of the present invention.

[0078] Example 1

[0079] (1) Select non-woven fabric A and impregnate it with PVA (polyvinyl alcohol). First, mix PVA powder and water in a large tank at a ratio of 3:100, control the temperature at 90-95°C, and after complete mixing and dissolution, add an appropriate amount of softener; obtain the required base fabric and roll up the base fabric. (2) Unwind the base fabric and place it into an impregnation tank for impregnation; the impregnation tank contains impregnation resin (the solid content of the impregnation resin is 30%, the 100% modulus is 20-30kgf / cm, and the softening point is 140°C), dimethylformamide, tear-resistant additive, hydrolysis-resistant additive, and color paste in a ratio of 100:260:10:2:15. (3) The base fabric is sent to a pre-coagulation tank for pre-coagulation. The sugar content of the pre-coagulation liquid in the pre-coagulation tank is 30-32%. The pre-coagulated base fabric is then ironed and the prepared fabric is coated on the surface of the base fabric using a coating device. The ratio of resin A, resin B, dimethylformamide, non-ionic surfactant, hydrolysis-resistant additive, filler, and color paste in the fabric is 40:60:40:0.5:1:1:3. (4) The coated base fabric is sent to a coagulation tank for washing, heated by a heating roller, dried in an oven, cooled by a cooling roller, and rolled up in sequence to obtain a space leather layer. The space leather layer is weighed, subjected to tear strength test, burst strength test, and back composite hot melt adhesive peel strength test. (5) A hot melt adhesive layer is composited on the back of the space leather layer. The temperature during the composite is controlled at 150±1°C to obtain synthetic leather.

[0080] Example 2

[0081] (1) Select non-woven fabric A and impregnate it with PVA (polyvinyl alcohol). First, mix PVA powder and water in a large tank at a ratio of 3:100, control the temperature at 90-95°C, and after complete mixing and dissolution, add an appropriate amount of softener; obtain the required base fabric and roll up the base fabric. (2) Unwind the base fabric and place it into an impregnation tank for impregnation; the impregnation tank contains impregnation resin (the solid content of the impregnation resin is 30%, the 100% modulus is 20-30kgf / cm, and the softening point is 140°C), dimethylformamide, tear-resistant additive, hydrolysis-resistant additive, and color paste in a ratio of 100:260:10:2:15. (3) The base fabric is sent to a pre-coagulation tank for pre-coagulation; the pre-coagulated base fabric is then ironed, and then the prepared fabric is scraped onto the surface of the base fabric using a coating device; the ratio of resin A, resin B, dimethylformamide, non-ionic surfactant, hydrolysis-resistant additive, filler, and color paste in the fabric is 20:80:40:0.5:1:1:3. (4) The base fabric coated with the fabric is sent to a coagulation tank for washing, a heating roller for heating, an oven for drying, a cooling roller for cooling, and a winding process in sequence to obtain a space leather layer; the space leather layer is weighed, subjected to tear strength tests, burst strength tests, and a back composite hot melt adhesive peeling strength test. (5) A hot melt adhesive layer is composited on the back of the space leather layer, and the temperature during the composite process is controlled at 150±1°C to obtain synthetic leather.

[0082] Example 3

[0083] (1) Select non-woven fabric A and impregnate it with PVA (polyvinyl alcohol). First, mix PVA powder and water in a large tank at a ratio of 3:100, control the temperature at 90-95°C, and after complete mixing and dissolution, add an appropriate amount of softener to obtain the required base fabric and roll it up. (2) Unwind the base fabric and place it into an impregnation tank for impregnation. The impregnation tank contains impregnation resin (the solid content of the impregnation resin is 30%, the 100% modulus is 20-30kgf / cm, and the softening point is 140°C), dimethylformamide, tear-resistant additive, hydrolysis-resistant additive, and color paste in a ratio of 100:260:5:2:15. (3) The base fabric is sent to a pre-coagulation tank for pre-coagulation; the pre-coagulated base fabric is then ironed, and then the prepared fabric is scraped onto the surface of the base fabric using a coating device; the ratio of resin A, resin B, dimethylformamide, non-ionic surfactant, hydrolysis-resistant additive, filler, and color paste in the fabric is 20:80:40:0.5:1:1:3. (4) The base fabric coated with the fabric is sent to a coagulation tank for washing, a heating roller for heating, an oven for drying, a cooling roller for cooling, and a winding process in sequence to obtain a space leather layer; the space leather layer is weighed, subjected to tear strength tests, burst strength tests, and a back composite hot melt adhesive peeling strength test. (5) A hot melt adhesive layer is composited on the back of the space leather layer, and the temperature during the composite process is controlled at 150±1°C to obtain synthetic leather.

[0084] Comparative Example 1

[0085] (1) Select non-woven fabric A and impregnate it with PVA (polyvinyl alcohol). First, mix PVA powder and water in a large tank at a ratio of 4:100, control the temperature at 90-95°C, and after complete mixing and dissolution, add an appropriate amount of softener; obtain the required base fabric and roll up the base fabric. (2) Unwind the base fabric and place it into an impregnation tank for impregnation; the impregnation tank contains impregnation resin (the solid content of the impregnation resin is 30%, the 100% modulus is 20-30kgf / cm, and the softening point is 140°C), dimethylformamide, tear-resistant additive, hydrolysis-resistant additive, and color paste in a ratio of 100:260:10:2:15. (3) The base fabric is sent to a pre-coagulation tank for pre-coagulation. The sugar content of the pre-coagulation liquid in the pre-coagulation tank is 30-32%. The pre-coagulated base fabric is then ironed and the prepared fabric is coated on the surface of the base fabric using a coating device. The ratio of resin A, resin B, dimethylformamide, non-ionic surfactant, hydrolysis-resistant additive, filler, and color paste in the fabric is 40:60:40:0.5:1:1:3. (4) The coated base fabric is sent to a coagulation tank for washing, heated by a heating roller, dried in an oven, cooled by a cooling roller, and rolled up in sequence to obtain a space leather layer. The space leather layer is weighed, subjected to tear strength test, burst strength test, and back composite hot melt adhesive peel strength test. (5) A hot melt adhesive layer is composited on the back of the space leather layer. The temperature during the composite is controlled at 150±1°C to obtain synthetic leather.

[0086] Comparative Example 2

[0087] (1) Select non-woven fabric A and impregnate it with PVA (polyvinyl alcohol). First, mix PVA powder and water in a large tank at a ratio of 2:100, control the temperature at 90-95°C, and after complete mixing and dissolution, add an appropriate amount of softener; obtain the required base fabric and roll up the base fabric. (2) Unwind the base fabric and place it into an impregnation tank for impregnation; the impregnation tank contains impregnation resin (the solid content of the impregnation resin is 30%, the 100% modulus is 20-30kgf / cm, and the softening point is 140°C), dimethylformamide, tear-resistant additive, hydrolysis-resistant additive, and color paste in a ratio of 100:260:10:2:15. (3) The base fabric is sent to a pre-coagulation tank for pre-coagulation. The sugar content of the pre-coagulation liquid in the pre-coagulation tank is 30-32%. The pre-coagulated base fabric is then ironed and the prepared fabric is coated on the surface of the base fabric using a coating device. The ratio of resin A, resin B, dimethylformamide, non-ionic surfactant, hydrolysis-resistant additive, filler, and color paste in the fabric is 40:60:40:0.5:1:1:3. (4) The coated base fabric is sent to a coagulation tank for washing, heated by a heating roller, dried in an oven, cooled by a cooling roller, and rolled up in sequence to obtain a space leather layer. The space leather layer is weighed, subjected to tear strength test, burst strength test, and back composite hot melt adhesive peel strength test. (5) A hot melt adhesive layer is composited on the back of the space leather layer. The temperature during the composite is controlled at 150±1°C to obtain synthetic leather.

[0088] Comparative Example 3

[0089] (1) Select non-woven fabric A and impregnate it with PVA (polyvinyl alcohol). First, mix PVA powder and water in a large tank at a ratio of 2:100 and evenly mix them. The temperature is controlled at 90-95°C until they are completely mixed and dissolved. The desired base fabric is obtained and rolled up. (2) Unwind the base fabric and place it into an impregnation tank for impregnation. The impregnation tank contains impregnation resin (the solid content of the impregnation resin is 30%, the 100% modulus is 20-30kgf / cm, and the softening point is 140°C), dimethylformamide, tear-resistant additive, hydrolysis-resistant additive, and color paste in a ratio of 100:260:10:2:15. (3) The base fabric is sent to a pre-coagulation tank for pre-coagulation. The sugar content of the pre-coagulation liquid in the pre-coagulation tank is 30-32%. The pre-coagulated base fabric is then ironed and the prepared fabric is coated on the surface of the base fabric using a coating device. The ratio of resin A, resin B, dimethylformamide, non-ionic surfactant, hydrolysis-resistant additive, filler, and color paste in the fabric is 40:60:40:0.5:1:1:3. (4) The coated base fabric is sent to a coagulation tank for washing, heated by a heating roller, dried in an oven, cooled by a cooling roller, and rolled up in sequence to obtain a space leather layer. The space leather layer is weighed, subjected to tear strength test, burst strength test, and back composite hot melt adhesive peel strength test. (5) A hot melt adhesive layer is composited on the back of the space leather layer. The temperature during the composite is controlled at 150±1°C to obtain synthetic leather.

[0090] Comparative Example 4

[0091] (1) Select non-woven fabric A, which is the required base fabric, and roll up the base fabric. (2) Unwind the base fabric and place it into an impregnation tank for impregnation; the ratio of the impregnation resin (the solid content of the impregnation resin is 30%, the 100% modulus is 20-30 kgf / cm, and the softening point is 140°C), dimethylformamide, tear-resistant additive, hydrolysis-resistant additive, and color paste in the impregnation tank is 100:260:10:2:15. (3) Send the base fabric into a pre-coagulation tank for pre-coagulation, and the sugar content of the pre-coagulation liquid in the pre-coagulation tank is 30-32%; the pre-coagulated base fabric is then ironed, and then the prepared fabric is scraped onto the surface of the base fabric using a coating device; the ratio of resin A, resin B, dimethylformamide, non-ionic surfactant, hydrolysis-resistant additive, filler, and color paste in the fabric is 40:60:40:0.5:1:1:3. (4) The coated base fabric is sequentially fed into a coagulation process, washed in a water washing tank, heated by a heating roller, dried in an oven, cooled by a cooling roller, and wound up to obtain a space leather layer. The space leather layer is then weighed, subjected to tear strength tests, burst strength tests, and a peel strength test of the back composite hot melt adhesive. (5) A hot melt adhesive layer is laminated onto the back of the space leather layer, with the temperature during the lamination controlled at 150±1°C, to obtain synthetic leather.

[0092] Comparative Example 5

[0093] (1) Select non-woven fabric B (parameters are thickness 0.35-0.45mm, weight 150g / m2, blasting 14kgf / cm 2, tensile strength warp and weft> 220N / 3cm, elongation at break in warp 40-90, elongation at break in weft 50-140%, tear strength warp and weft> 60N / 3cm, nylon content is 70%), non-woven fabric B is first impregnated with PVA (polyvinyl alcohol), first PVA powder and water are mixed evenly in a large tank at a ratio of 3:100, the temperature is controlled at 90-95℃, after complete mixing and dissolution, an appropriate amount of softener is added; the required base fabric is obtained and the base fabric is rolled up. (2) The base fabric is unrolled and put into the impregnation tank for impregnation; the impregnation tank contains impregnation resin (the solid content of the impregnation resin is 30%, the 100% modulus is 20-30kgf / cm, and the softening point is 140℃), dimethylformamide, anti-tear additive, hydrolysis-resistant additive, and color paste in a ratio of 100:260:10:2:15. (3) The base fabric is sent to a pre-coagulation tank for pre-coagulation. The sugar content of the pre-coagulation liquid in the pre-coagulation tank is 30-32%. The pre-coagulated base fabric is then ironed and the prepared fabric is coated on the surface of the base fabric using a coating device. The ratio of resin A, resin B, dimethylformamide, non-ionic surfactant, hydrolysis-resistant additive, filler, and color paste in the fabric is 40:60:40:0.5:1:1:3. (4) The coated base fabric is sent to a coagulation tank for washing, heated by a heating roller, dried in an oven, cooled by a cooling roller, and rolled up in sequence to obtain a space leather layer. The space leather layer is weighed, subjected to tear strength test, burst strength test, and back composite hot melt adhesive peel strength test. (5) A hot melt adhesive layer is composited on the back of the space leather layer. The temperature during the composite is controlled at 150±1°C to obtain synthetic leather.

[0094] Comparative Example 6

[0095] (1) Select non-woven fabric A and impregnate it with PVA (polyvinyl alcohol). First, mix PVA powder and water in a large tank at a ratio of 3:100, control the temperature at 90-95°C, and after complete mixing and dissolution, add an appropriate amount of softener to obtain the required base fabric and roll it up. (2) Unwind the base fabric and place it into an impregnation tank for impregnation. The impregnation tank contains impregnation resin (the solid content of the impregnation resin is 30%, the 100% modulus is 20-30kgf / cm, and the softening point is 170°C), dimethylformamide, tear-resistant additive, hydrolysis-resistant additive, and color paste in a ratio of 100:260:10:2:15. (3) The base fabric is sent to a pre-coagulation tank for pre-coagulation. The sugar content of the pre-coagulation liquid in the pre-coagulation tank is 30-32%. The pre-coagulated base fabric is then ironed and the prepared fabric is coated on the surface of the base fabric using a coating device. The ratio of resin A, resin B, dimethylformamide, non-ionic surfactant, hydrolysis-resistant additive, filler, and color paste in the fabric is 40:60:40:0.5:1:1:3. (4) The coated base fabric is sent to a coagulation tank for washing, heated by a heating roller, dried in an oven, cooled by a cooling roller, and rolled up in sequence to obtain a space leather layer. The space leather layer is weighed, subjected to tear strength test, burst strength test, and back composite hot melt adhesive peel strength test. (5) A hot melt adhesive layer is composited on the back of the space leather layer. The temperature during the composite is controlled at 150±1°C to obtain synthetic leather.

[0096] Comparative Example 7

[0097] (1) Select non-woven fabric A and impregnate it with PVA (polyvinyl alcohol). First, mix PVA powder and water in a large tank at a ratio of 3:100, control the temperature at 90-95°C, and after complete mixing and dissolution, add an appropriate amount of softener; obtain the required base fabric and roll up the base fabric. (2) Unwind the base fabric and place it into an impregnation tank for impregnation; the impregnation tank contains impregnation resin (the solid content of the impregnation resin is 30%, the 100% modulus is 20-30kgf / cm, and the softening point is 140°C), dimethylformamide, tear-resistant additive, hydrolysis-resistant additive, and color paste in a ratio of 100:260:10:2:15. (3) The base fabric is sent to a pre-coagulation tank for pre-coagulation. The sugar content of the pre-coagulation liquid in the pre-coagulation tank is 30-32%. The pre-coagulated base fabric is then ironed and the prepared fabric is coated on the surface of the base fabric using a coating device. The ratio of resin A, resin B, dimethylformamide, non-ionic surfactant, hydrolysis-resistant additive, and color paste in the fabric is 40:60:40:0.5:1:3. (4) The coated base fabric is sent to a coagulation tank for washing, heated by a heating roller, dried in an oven, cooled by a cooling roller, and rolled up in sequence to obtain a space leather layer. The space leather layer is weighed, subjected to tear strength test, burst strength test, and back composite hot melt adhesive peel strength test. (5) A hot melt adhesive layer is composited on the back of the space leather layer. The temperature during the composite is controlled at 150±1°C to obtain synthetic leather.

[0098] Comparative Example 8

[0099] (1) Select non-woven fabric A and impregnate it with PVA (polyvinyl alcohol). First, mix PVA powder and water in a large tank at a ratio of 3:100, control the temperature at 90-95°C, and after complete mixing and dissolution, add an appropriate amount of softener; obtain the required base fabric and roll up the base fabric. (2) Unwind the base fabric and place it into an impregnation tank for impregnation; the impregnation tank contains impregnation resin (the solid content of the impregnation resin is 30%, the 100% modulus is 20-30kgf / cm, and the softening point is 140°C), dimethylformamide, tear-resistant additive, hydrolysis-resistant additive, and color paste in a ratio of 100:260:10:2:15. (3) The base fabric is sent to a pre-coagulation tank for pre-coagulation. The sugar content of the pre-coagulation liquid in the pre-coagulation tank is 30-32%. The pre-coagulated base fabric is then ironed and the prepared fabric is coated on the surface of the base fabric using a coating device. The ratio of resin A, resin B, dimethylformamide, non-ionic surfactant, hydrolysis-resistant additive, and color paste in the fabric is 40:60:40:0.5:1:3. (4) The base fabric coated with the fabric is sent to a coagulation tank for washing, a heating roller for heating, an oven for drying, a cooling roller for cooling, and a winding process to obtain a space leather layer. The space leather layer is weighed, subjected to tear strength test, burst strength test, and back composite hot melt adhesive peeling strength test. (5) A hot melt adhesive layer is composited on the back of the space leather layer. The temperature during the composite process is controlled at 160°C to obtain synthetic leather.

[0100] Comparative Example 9

[0101] (1) Select non-woven fabric A and impregnate it with PVA (polyvinyl alcohol). First, mix PVA powder and water in a large tank at a ratio of 3:100, control the temperature at 90-95°C, and after complete mixing and dissolution, add an appropriate amount of softener; obtain the required base fabric and roll up the base fabric. (2) Unwind the base fabric and place it into an impregnation tank for impregnation; the impregnation tank contains impregnation resin (the solid content of the impregnation resin is 30%, the 100% modulus is 20-30kgf / cm, and the softening point is 140°C), dimethylformamide, tear-resistant additive, hydrolysis-resistant additive, and color paste in a ratio of 100:260:10:2:15. (3) The base fabric is sent to a pre-coagulation tank for pre-coagulation. The sugar content of the pre-coagulation liquid in the pre-coagulation tank is 30-32%. The pre-coagulated base fabric is then ironed and the prepared fabric is coated on the surface of the base fabric using a coating device. The ratio of resin A, resin B, dimethylformamide, non-ionic surfactant, hydrolysis-resistant additive, and color paste in the fabric is 40:60:40:0.5:1:3. (4) The base fabric coated with the fabric is sent to a coagulation tank for washing, a heating roller for heating, an oven for drying, a cooling roller for cooling, and a winding process to obtain a space leather layer. The space leather layer is weighed, subjected to tear strength test, burst strength test, and back composite hot melt adhesive peeling strength test. (5) A hot melt adhesive layer is composited on the back of the space leather layer. The temperature during the composite process is controlled at 145°C to obtain synthetic leather.

[0102] Table 1 Comparison of test results of various embodiments and comparative examples

[0103]

[0104]

[0105] According to Table 1:

[0106] From comparative example 1, it can be seen that when there is too much PVA powder, the penetration effect of the base fabric will be worse, which will affect the weight and feel and will not meet product requirements.

[0107] From the comparative example 2, it can be seen that when the PVA powder is too little, the base fabric penetration effect is still good, which also affects the gram weight and feel, and does not meet the product requirements.

[0108] It can be seen from Comparative Example 3 that without adding softener, the softness value of the product is reduced.

[0109] From Comparative Example 4, it can be seen that the non-woven fabric A is not treated with the PVA impregnation process, the product weight is lighter, but the tear strength is worse and the softness value is reduced.

[0110] From comparative example 5, it can be seen that although the tear strength and burst strength of non-woven fabric B are changed, the weight of the product is too large and the softness value is too low. At the same time, there are burrs on the surface of the product, which makes the hand feel bad.

[0111] It can be seen from Comparative Example 6 that the use of an impregnated resin with a softening point of 170°C results in a significant reduction in the peel strength of the subsequent composite hot melt adhesive layer on the back of the space leather layer, and the adhesion between the hot melt adhesive and the back of the space leather layer is likely to be insufficient.

[0112] It can be seen from Comparative Example 7 that when no filler is added, the weight of the produced space leather product is relatively high.

[0113] Comparative Examples 8 and 9 show that when the lamination temperature is higher than 155°C, there is a risk of glue overflow and sticking. When the temperature is lower than 145°C, the hot melt adhesive is likely to have insufficient adhesion to the back of the space leather layer.

[0114] Although the specific embodiments of the present invention are described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for producing a thin composite synthetic leather, characterized by: The synthetic leather comprises a space leather layer and a hot melt adhesive layer compounded on the back of the space leather layer; The production method comprises the following steps: (1) Select suitable non-woven fabric with a thickness of 0.35-0.45 mm and a weight of 120 g / m 2 , blasting is 14kgf / cm 2 , tensile strength in warp and weft directions>200N / 3cm, elongation at break in warp direction 30-90%, elongation at break in weft direction 50-150%, tear strength in warp and weft directions>60N / 3cm, nylon content is 70%; the non-woven fabric is first impregnated with PVA, first mix PVA powder and water in a ratio of 3:100, control the temperature at 90-95℃, after complete mixing and dissolution, add appropriate amount of softener to obtain the required base fabric, and then roll it up; (2) unwinding the base fabric into an impregnation tank for impregnation; (3) sending the base fabric into a pre-coagulation tank for pre-coagulation, ironing the pre-coagulated base fabric, and then using a coating device to scrape the prepared fabric onto the surface of the base fabric; (4) The coated base fabric is sequentially sent to the second coagulation tank for coagulation, washed in a water washing tank, heated by a heating roller, dried in an oven, cooled by a cooling roller, and rolled up to obtain a space leather layer; (5) Compounding a hot melt adhesive layer on the back of the space leather layer, controlling the temperature during compounding at 150±1°C, to obtain synthetic leather.

2. The method for producing a thin and light composite synthetic leather according to claim 1, wherein: In step (2), the formula of the impregnation material in the impregnation tank includes impregnation resin, dimethylformamide, anti-tear aid, hydrolysis resistance aid, and color paste; the ratio of the impregnation resin, dimethylformamide, anti-tear aid, hydrolysis resistance aid, and color paste is 100:260:(5-10):2:15; The prepared impregnation liquid is stirred at room temperature at a stirring speed of 1000-1500 r / min for 15-20 minutes until it is completely dissolved. The viscosity of the impregnation material is controlled at 200-260 cps.

3. The method for producing a thin and light composite synthetic leather according to claim 2, wherein: The impregnation resin has a solid content of 30%, a 100% modulus of 20-30 kgf / cm, and a softening point of 140°C.

4. The method for producing a thin and light composite synthetic leather according to claim 1, wherein: In step (3), the pressure of the hydraulic roller in the pre-coagulation tank is controlled to be 5-5.5 kg, and the sugar content of the pre-coagulation liquid in the pre-coagulation tank is 30-32%.

5. The method for producing a light and thin composite synthetic leather according to claim 4, wherein: In step (3), the coating device controls the thickness of the coating by adjusting the gap between the coating knives. The coating gap is controlled between 90±5 mm and the coating amount is 0.95±0.05 kg / y.

6. The method for producing a light and thin composite synthetic leather according to claim 5, wherein: In step (3), the fabric formula includes resin A, resin B, dimethylformamide, nonionic surfactant, hydrolysis-resistant additive, filler, and color paste; the ratio of resin A, resin B, dimethylformamide, nonionic surfactant, hydrolysis-resistant additive, filler, and color paste is (20-40): (60-80): 40: 0.5: 1: 1: 3; The resin A has a solid content of 35%, a 100% modulus of 25-35 kgf / cm, a tensile strength of >40 MPa, and an elongation of ≥400%. The resin B has a solid content of 35%, a 100% modulus of 80-90 kgf / cm, a tensile strength of >45 MPa, and an elongation of ≥350%; The prepared fabric is stirred at a high speed of 1000-1500 r / min at room temperature for 30-35 minutes until it is completely and evenly dissolved, and the stirring speed is reduced to 300±50 r / min, and vacuum degassing is performed for 90 minutes. The viscosity of the fabric is controlled at 16000-17000 cps.

7. The method for producing a light and thin composite synthetic leather according to claim 1, wherein: In step (4), the coagulation sugar content in the second coagulation tank is 17-21%, and the temperature is controlled at 30±2°C; after the base fabric coated with the fabric comes out of the second coagulation tank, the surface condition of the synthetic leather is observed, and the thickness and width are measured. The thickness is controlled to be between 0.6-0.65mm, and the width is between 1.47-1.49m; The water washing tanks include 15 groups of water washing tanks. The sugar content of the first six groups is controlled at 20-10%, the sugar content of the middle six groups is controlled at 10-0%, and the sugar content of the last three groups is 0%. The water washing temperature of the last three groups is controlled at 60±5℃. The ovens include five groups, the oven temperature of the first group is 160° C., the oven temperature of the second to fourth groups is 170° C., and the oven temperature of the fifth group is 160° C. until the products are completely dried.

8. The method for producing a light and thin composite synthetic leather according to claim 1, wherein: In step (5), the thickness of the hot melt adhesive layer is controlled to be 0.15-0.20 mm.

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