Embossed full-water-based polyurethane synthetic leather for sports and leisure shoes and preparation method thereof

Abstract

The present application relates to a kind of embossed full water-based polyurethane synthetic leather for sports leisure shoes and its preparation method.The preparation method includes the following steps: S1.after the PH value of water-based polyurethane resin slurry is adjusted to neutral, pre-foaming auxiliary agent is added, stirring is uniformly, and then standing, to obtain water-based polyurethane coating slurry;S2.water-based polyurethane coating slurry is coated on the surface of non-woven fabric after water-based slurry pretreatment, first through weak acid gradient condensation liquid A to carry out the first condensation, then through weak acid gradient condensation liquid B to carry out the second condensation, to obtain water-based polyurethane wet process bees;S3.water-based polyurethane wet process bees are pasted after dry release paper water-based, preheating, then embossing process treatment, to obtain the embossed full water-based polyurethane synthetic leather for sports leisure shoes.The synthetic leather prepared by the present application has the characteristics of good pattern three-dimensionality, soft hand feeling and high physical strength by preheating water-based polyurethane synthetic leather.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyurethane synthetic leather, in particular to a embossed full water-based polyurethane synthetic leather for sports and casual shoes and a preparation method thereof. BACKGROUND

[0002] Polyurethane synthetic leather belongs to a kind of polyurethane elastomer, which has soft and natural gloss, soft hand feeling and strong leather appearance, excellent adhesion to base material, excellent mechanical properties such as wear resistance, flex resistance and aging resistance, good cold resistance, air permeability, washability, easy processing and low price, and is the most ideal substitute for natural leather.

[0003] The high molecular chain of water-based polyurethane can make the resin have multiple functions: water resistance, solvent resistance, wear resistance, scratch resistance, wrinkle resistance, moisture permeability, air permeability and hand feeling are closer to leather than synthetic leather made of solvent-based resin. The use of water-based polyurethane resin to produce synthetic leather not only meets international environmental protection standards in terms of chemical properties, but also greatly improves the performance of synthetic leather in terms of physical properties. However, at present, in the technical field of water-based polyurethane synthetic leather, there are certain limitations in processing and strength of full water-based polyurethane synthetic leather, especially embossed products. In production, the surface of water-based polyurethane synthetic leather is directly extruded by high-temperature embossing roller with a certain pressure, and finally the polyurethane high polymer is softened and shaped to form a concave-convex three-dimensional pattern. The temperature of the embossing roller is generally higher than the softening point temperature of the polyurethane high polymer. When the surface of the polyurethane synthetic leather contacts the embossing roller, the temperature rises sharply, and part of the polyurethane high polymer softens rapidly, which easily leads to the problems of stiff hand feeling, low thickness retention rate, unsatisfactory pattern, weak three-dimensional effect and low peel strength of the water-based polyurethane synthetic leather after embossing, thereby limiting its application in the field of sports and casual shoes. SUMMARY

[0004] Therefore, it is necessary to provide a embossed full water-based polyurethane synthetic leather for sports and casual shoes and a preparation method thereof to solve the problems of stiff hand feeling, low thickness retention rate, unsatisfactory pattern, weak three-dimensional effect and low peel strength of the water-based polyurethane synthetic leather after embossing, thereby limiting its application in the field of sports and casual shoes.

[0005] The preparation method of the embossed full water-based polyurethane synthetic leather for sports and casual shoes provided by the present application comprises the following steps:

[0006] S1. After adjusting the PH value of the water-based polyurethane resin slurry to neutral, adding a pre-foaming aid, stirring uniformly and standing, a water-based polyurethane coating slurry is obtained;

[0007] S2. The waterborne polyurethane coating slurry is coated onto the surface of the nonwoven fabric after waterborne slurry pretreatment. It is first coagulated by weak acid gradient coagulation liquid A, and then coagulated by weak acid gradient coagulation liquid B to obtain waterborne polyurethane wet process base. The concentration of the weak acid gradient coagulation liquid A is less than the concentration of the weak acid gradient coagulation liquid B.

[0008] S3. The waterborne polyurethane wet-process base is preheated after being laminated with dry release paper and then subjected to embossing process to obtain embossed all-waterborne polyurethane synthetic leather for sports and leisure shoes.

[0009] As a further improvement to the above scheme, in step S1, the mass fractions of each component in the waterborne polyurethane coating slurry are as follows: 85-95 parts waterborne polyurethane resin, 5-15 parts deionized water, 1-2 parts thickener, 0.2-0.5 parts crosslinking agent, 1.5-2 parts pH adjuster, 0-10 parts waterborne pigment, and 0.2-0.6 parts pre-foaming aid.

[0010] As a further improvement to the above scheme, the pre-foaming agent is NaHCO3 powder.

[0011] As a further improvement to the above scheme, in step S1, the rotor speed of the stirring is 1000-1500 rpm, and the stirring time is 20-30 minutes.

[0012] As a further improvement to the above scheme, in step S1, the settling time is 20-30 minutes.

[0013] As a further improvement to the above scheme, in step S2, the concentration of the weak acid gradient coagulation liquid A is 0.2-0.6 wt%, and the time for the first coagulation is 3-5 minutes.

[0014] As a further improvement to the above scheme, in step S2, the concentration of the weak acid gradient coagulation liquid B is 1.2-1.6 wt%, and the second coagulation time is 3-5 minutes.

[0015] As a further improvement to the above scheme, in step S2, the pretreatment process of the nonwoven fabric after water-based slurry pretreatment is as follows: the nonwoven fabric base is impregnated and extruded with water-based slurry, then enters a 0.5-1.5% oxalic acid solution for pre-coagulation, and then is ironed flat by ironing rollers to obtain the nonwoven fabric after water-based slurry pretreatment.

[0016] As a further improvement to the above scheme, in step S2, the preheating is to first gradually heat the waterborne polyurethane wet-process base to 80℃-100℃, and then gradually heat the waterborne polyurethane wet-process base to 120℃-140℃.

[0017] The present invention provides an embossed, water-based polyurethane synthetic leather for sports and leisure shoes, which is prepared by the preparation method described above.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The method of this invention first adjusts the pH value of the waterborne polyurethane resin slurry to neutral before adding a pre-foaming agent. On the one hand, since waterborne polyurethane is generally in an ionic state, adjusting the pH to neutral enhances the stability of the waterborne polyurethane solution and prevents early demulsification and precipitation. On the other hand, adding the pre-foaming agent provides a stable neutral environment, preventing premature decomposition of the waterborne polyurethane and subsequent loss of foaming performance in the coagulation liquid. Furthermore, the pre-foaming agent uses NaHCO3 powder. When the waterborne polyurethane slurry is coated onto the fabric surface and passes through a weakly acidic coagulation liquid, the NaHCO3 powder slowly decomposes and releases CO2 gas as the waterborne polyurethane polymer is released. This CO2 gas fills the polyurethane film, forming a rich microporous structure within the film, achieving a soft feel and facilitating subsequent embossing of the product.

[0020] 2. This invention employs a two-step method to coagulate the waterborne polyurethane coating slurry, resulting in a waterborne polyurethane base with uniform and abundant pores, a soft feel, and high peel strength, fully meeting the requirements of the sports and leisure footwear industry. Furthermore, the first coagulation uses a low-concentration weak acid coagulating solution A (0.2-0.6 wt%), resulting in slow pre-coagulation. At this stage, the waterborne polyurethane remains in a flowing gel state, allowing sufficient time and space for the CO2 gas released by the pre-foaming agent to distribute evenly within the polyurethane film. This also reduces the risk of uneven internal stress caused by excessively rapid coagulation during the polyurethane coagulation process, lowering the risk of surface cracking. After the first coagulation, the waterborne polyurethane film is then passed through a higher-concentration weak acid coagulating solution B (1.2-1.6%). The waterborne polyurethane film, now in a flowing gel state with a rich pore structure, undergoes rapid coagulation and molding, resulting in a waterborne polyurethane base with a smooth surface and abundant microporous structure.

[0021] 3. The present invention pre-heats waterborne polyurethane synthetic leather, allowing the synthetic leather to be heated gently from the outside in, appropriately reducing the surface temperature of the embossing roller, avoiding the rapid melting of waterborne polyurethane polymers caused by rapid heating, and solving the problems of stiff feel and low thickness retention caused by rapid temperature changes on the leather surface.

[0022] 4. The embossed, water-based polyurethane synthetic leather for sports and leisure shoes produced by this invention has a softness of 2.5-3.0mm, a peel strength ≥90N / 3CM, abrasion resistance (H-22*1KG) ≥500 times, and room temperature flexing ≥100,000 times. It is free of perfluorooctanoic acid (PFCs, PFOS, PFOA) and DMF, and has excellent water-based environmental performance. The polyurethane synthetic leather produced by the method of this invention meets the physical property standards for synthetic leather for sports and leisure shoes. It has the characteristics of good three-dimensional fullness of pattern, soft hand feel and high physical strength. Moreover, the entire production process and product are ecological and environmentally friendly, which is in line with the industrial development direction and market orientation. Detailed Implementation

[0023] To facilitate understanding of the present invention, a more comprehensive description will be given below with reference to specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0025] Example 1

[0026] This embodiment provides an embossed, water-based polyurethane synthetic leather for sports and leisure shoes, the preparation method of which includes the following steps S1-S3.

[0027] S1. Add pH adjuster at a mass fraction of 1.5% to the waterborne polyurethane resin slurry, stir evenly to adjust the pH value of the waterborne polyurethane resin slurry to neutral, then add pre-foaming agent NaHCO3 powder at a mass fraction of 0.2%, stir at a rotor speed of 1000 rpm for 20 minutes, after stirring evenly, let stand for 30 minutes to obtain a uniform and stable waterborne polyurethane coating slurry.

[0028] The preparation process of waterborne polyurethane resin slurry is as follows: Weigh 95 parts of waterborne polyurethane resin, 5 parts of deionized water, 1 part of thickener, 0.2 parts of crosslinking agent, and 5 parts of waterborne color paste according to the mass ratio; after mixing the polyurethane resin, deionized water, thickener, crosslinking agent, and waterborne color paste evenly, the waterborne polyurethane resin slurry is obtained.

[0029] The pH adjuster mentioned here refers to the alkaline adjuster, which is mainly a strong base-weak acid salt.

[0030] S2. Apply the waterborne polyurethane coating slurry to the surface of the nonwoven fabric after waterborne slurry pretreatment. First, perform the first coagulation by passing it through a weak acid gradient coagulation solution A with a concentration of 0.2 wt% for 5 minutes. Then, perform the second coagulation by passing it through a weak acid gradient coagulation solution B with a concentration of 1.2 wt% for 3 minutes to obtain the waterborne polyurethane wet-process base.

[0031] S3. After the water-based polyurethane wet-process base is applied with dry release paper water-based lamination, the water-based polyurethane wet-process base is first gradually heated to 80℃-100℃, then gradually heated to 120℃-140℃, and then subjected to embossing process to obtain embossed all-water-based polyurethane synthetic leather for sports and leisure shoes.

[0032] It should be noted that preheating device one and preheating device two can be installed at the feeding end of the embossing equipment. The water-based polyurethane wet-process base material first passes through preheating device one, which gradually heats the water-based polyurethane wet-process base material to 80℃-100℃ using a stepped heating method. After being preheated by preheating device one, the water-based polyurethane wet-process base material then passes through preheating device two, which gradually heats the water-based polyurethane wet-process base material to 120℃-140℃ using a stepped heating method. Preheating device one and preheating device two can be heat-conducting rollers or ovens.

[0033] The embossed, all-water-based polyurethane synthetic leather for sports and leisure shoes prepared in this embodiment was tested and found to have the following properties: a softness of 2.5 mm, a peel strength of 120 N / 3 cm, abrasion resistance (H-22*1 KG) of 700 times, and a room temperature flexing resistance of 150,000 times. It is free of perfluorooctanoic acid (PFCs, PFOS, PFOA) and DMF, and has excellent all-water-based environmental performance.

[0034] Example 2

[0035] This embodiment provides an embossed, water-based polyurethane synthetic leather for sports and leisure shoes, the preparation method of which includes the following steps S1-S3.

[0036] S1. Add pH adjuster at a mass fraction of 1.8% to the waterborne polyurethane resin slurry, stir evenly to adjust the pH value of the waterborne polyurethane resin slurry to neutral, then add pre-foaming agent NaHCO3 powder at a mass fraction of 0.4%, stir at a rotor speed of 1200 rpm for 25 minutes, after stirring evenly, let stand for 30 minutes to obtain a uniform and stable waterborne polyurethane coating slurry.

[0037] The preparation process of waterborne polyurethane resin slurry is as follows: Weigh 90 parts of waterborne polyurethane resin, 10 parts of deionized water, 1.5 parts of thickener, 0.3 parts of crosslinking agent, and 6 parts of waterborne color paste according to the mass ratio; after mixing the polyurethane resin, deionized water, thickener, crosslinking agent, and waterborne color paste evenly, the waterborne polyurethane resin slurry is obtained.

[0038] The pH adjuster mentioned here refers to the alkaline adjuster, which is mainly a strong base-weak acid salt.

[0039] S2. Apply the waterborne polyurethane coating slurry to the surface of the nonwoven fabric after waterborne slurry pretreatment. First, perform the first coagulation through a weak acid gradient coagulation solution A with a concentration of 0.4 wt%, with a first coagulation time of 4 minutes. Then, perform the second coagulation through a weak acid gradient coagulation solution B with a concentration of 1.4 wt%, with a second coagulation time of 5 minutes, to obtain the waterborne polyurethane wet-process base.

[0040] S3. After the water-based polyurethane wet-process base is applied with dry release paper water-based lamination, the water-based polyurethane wet-process base is first gradually heated to 80℃-100℃, then gradually heated to 120℃-140℃, and then subjected to embossing process to obtain embossed all-water-based polyurethane synthetic leather for sports and leisure shoes.

[0041] It should be noted that preheating device one and preheating device two can be installed at the feeding end of the embossing equipment. The water-based polyurethane wet-process base material first passes through preheating device one, which gradually heats the water-based polyurethane wet-process base material to 80℃-100℃ using a stepped heating method. After being preheated by preheating device one, the water-based polyurethane wet-process base material then passes through preheating device two, which gradually heats the water-based polyurethane wet-process base material to 120℃-140℃ using a stepped heating method. Preheating device one and preheating device two can be heat-conducting rollers or ovens.

[0042] The embossed, all-water-based polyurethane synthetic leather for sports and leisure shoes prepared in this embodiment was tested and found to have the following properties: a softness of 2.6 mm, a peel strength of 102 N / 3 cm, abrasion resistance (H-22*1KG) of 600 times, and a room temperature flexing resistance of 120,000 times. It is free of perfluorooctanoic acid (PFCs, PFOS, PFOA) and DMF, and has excellent all-water-based environmental performance.

[0043] Example 3

[0044] This embodiment provides an embossed, water-based polyurethane synthetic leather for sports and leisure shoes, the preparation method of which includes the following steps S1-S3.

[0045] S1. Add 2% by mass of pH adjuster to waterborne polyurethane resin slurry, stir evenly to adjust the pH value of waterborne polyurethane resin slurry to neutral, then add 0.6% by mass of pre-foaming agent NaHCO3 powder, stir at a rotor speed of 1500 rpm for 30 minutes, after stirring evenly, let stand for 30 minutes to obtain a uniform and stable waterborne polyurethane coating slurry.

[0046] The preparation process of waterborne polyurethane resin slurry is as follows: Weigh 90 parts of waterborne polyurethane resin, 15 parts of deionized water, 1.6 parts of thickener, 0.5 parts of crosslinking agent, and 8 parts of waterborne color paste according to the mass ratio; after mixing the polyurethane resin, deionized water, thickener, crosslinking agent, and waterborne color paste evenly, the waterborne polyurethane resin slurry is obtained.

[0047] The pH adjuster mentioned here refers to the alkaline adjuster, which is mainly a strong base-weak acid salt.

[0048] S2. Apply the waterborne polyurethane coating slurry to the surface of the nonwoven fabric after waterborne slurry pretreatment. First, perform the first coagulation by passing it through a weak acid gradient coagulation solution A with a concentration of 0.5 wt%, with a first coagulation time of 5 minutes. Then, perform the second coagulation by passing it through a weak acid gradient coagulation solution B with a concentration of 1.5 wt%, with a second coagulation time of 5 minutes, to obtain the waterborne polyurethane wet-process base.

[0049] S3. After the water-based polyurethane wet-process base is applied with dry release paper water-based lamination, the water-based polyurethane wet-process base is first gradually heated to 80℃-100℃, then gradually heated to 120℃-140℃, and then subjected to embossing process to obtain embossed all-water-based polyurethane synthetic leather for sports and leisure shoes.

[0050] It should be noted that preheating device one and preheating device two can be installed at the feeding end of the embossing equipment. The water-based polyurethane wet-process base material first passes through preheating device one, which gradually heats the water-based polyurethane wet-process base material to 80℃-100℃ using a stepped heating method. After being preheated by preheating device one, the water-based polyurethane wet-process base material then passes through preheating device two, which gradually heats the water-based polyurethane wet-process base material to 120℃-140℃ using a stepped heating method. Preheating device one and preheating device two can be heat-conducting rollers or ovens.

[0051] The embossed, all-water-based polyurethane synthetic leather for sports and leisure shoes prepared in this embodiment was tested and found to have the following properties: a softness of 2.9 mm, a peel strength of 95 N / 3 cm, abrasion resistance (H-22*1KG) of 500 times, and a room temperature flexing resistance of 100,000 times. It is free of perfluorooctanoic acid (PFCs, PFOS, PFOA) and DMF, and has excellent all-water-based environmental performance.

[0052] Comparative Example 1

[0053] This embodiment provides an embossed, water-based polyurethane synthetic leather for sports and leisure shoes, the preparation method of which includes the following steps S1-S3.

[0054] S1. Add 2% by mass of pH adjuster to waterborne polyurethane resin slurry, stir evenly to adjust the pH value of waterborne polyurethane resin slurry to neutral, then add 0.6% by mass of pre-foaming agent NaHCO3 powder, stir at a rotor speed of 1500 rpm for 30 minutes, after stirring evenly, let stand for 30 minutes to obtain a uniform and stable waterborne polyurethane coating slurry.

[0055] The preparation process of waterborne polyurethane resin slurry is as follows: Weigh 90 parts of waterborne polyurethane resin, 15 parts of deionized water, 1.6 parts of thickener, 0.5 parts of crosslinking agent, and 8 parts of waterborne color paste according to the mass ratio; after mixing the polyurethane resin, deionized water, thickener, crosslinking agent, and waterborne color paste evenly, the waterborne polyurethane resin slurry is obtained.

[0056] S2. Apply the waterborne polyurethane coating slurry to the surface of the nonwoven fabric after waterborne slurry pretreatment. First, perform the first coagulation by passing it through a weak acid gradient coagulation solution A with a concentration of 0.5 wt%, with a first coagulation time of 5 minutes. Then, perform the second coagulation by passing it through a weak acid gradient coagulation solution B with a concentration of 1.5 wt%, with a second coagulation time of 5 minutes, to obtain the waterborne polyurethane wet-process base.

[0057] S3. After the water-based polyurethane wet-process base is laminated with dry release paper, it is directly subjected to embossing process to obtain embossed all-water-based polyurethane synthetic leather for sports and leisure shoes.

[0058] The embossed all-waterborne polyurethane synthetic leather for sports and leisure shoes prepared in this embodiment has a stiff feel, a softness of 2.1 mm, unsatisfactory pattern fullness, and reduced peel strength and resistance to room temperature bending. It cannot fully meet the requirements for embossed all-waterborne polyurethane synthetic leather for sports and leisure shoes.

[0059] Comparative Example 2

[0060] This embodiment provides an embossed, water-based polyurethane synthetic leather for sports and leisure shoes, the preparation method of which includes the following steps S1-S3.

[0061] S1. Add 0.6% by mass of NaHCO3 powder, a pre-foaming agent, to the waterborne polyurethane resin slurry. Stir at a rotor speed of 1500 rpm for 30 minutes. After stirring evenly, let stand for 30 minutes to obtain the waterborne polyurethane coating slurry.

[0062] The preparation process of waterborne polyurethane resin slurry is as follows: Weigh 90 parts of waterborne polyurethane resin, 15 parts of deionized water, 1.6 parts of thickener, 0.5 parts of crosslinking agent, and 8 parts of waterborne color paste according to the mass ratio; after mixing the polyurethane resin, deionized water, thickener, crosslinking agent, and waterborne color paste evenly, the waterborne polyurethane resin slurry is obtained.

[0063] S2. Apply the waterborne polyurethane coating slurry to the surface of the nonwoven fabric after waterborne slurry pretreatment. First, perform the first coagulation by passing it through a weak acid gradient coagulation solution A with a concentration of 0.5 wt%, with a first coagulation time of 5 minutes. Then, perform the second coagulation by passing it through a weak acid gradient coagulation solution B with a concentration of 1.5 wt%, with a second coagulation time of 5 minutes, to obtain the waterborne polyurethane wet-process base.

[0064] S3. After the water-based polyurethane wet-process base is applied to the dry release paper water-based surface, it is first preheated to 80℃-100℃, and then gradually preheated to 120℃-140℃. Then, it is subjected to embossing process to obtain embossed water-based polyurethane synthetic leather for sports and leisure shoes.

[0065] The embossed all-waterborne polyurethane synthetic leather for sports and leisure shoes prepared in this comparative example has poor hand softness, with a softness of 2.3mm, poor pattern clarity, a peel strength of 90N / 3CM, and a crack resistance of 100,000 flexes at room temperature. It cannot fully meet the requirements for embossed all-waterborne polyurethane synthetic leather for sports and leisure shoes.

[0066] Comparative Example 3

[0067] This embodiment provides an embossed, water-based polyurethane synthetic leather for sports and leisure shoes, the preparation method of which includes the following steps S1-S3.

[0068] S1. Add the pH adjuster to the waterborne polyurethane resin slurry at a mass fraction of 2%, stir evenly, and adjust the pH value of the waterborne polyurethane resin slurry to neutral to obtain the waterborne polyurethane coating slurry.

[0069] The preparation process of waterborne polyurethane resin slurry is as follows: Weigh 90 parts of waterborne polyurethane resin, 15 parts of deionized water, 1.6 parts of thickener, 0.5 parts of crosslinking agent, and 8 parts of waterborne color paste according to the mass ratio; after mixing the polyurethane resin, deionized water, thickener, crosslinking agent, and waterborne color paste evenly, the waterborne polyurethane resin slurry is obtained.

[0070] S2. Apply the waterborne polyurethane coating slurry to the surface of the nonwoven fabric after waterborne slurry pretreatment. First, perform the first coagulation by passing it through a weak acid gradient coagulation solution A with a concentration of 0.5 wt%, with a first coagulation time of 5 minutes. Then, perform the second coagulation by passing it through a weak acid gradient coagulation solution B with a concentration of 1.5 wt%, with a second coagulation time of 5 minutes, to obtain the waterborne polyurethane wet-process base.

[0071] S3. After the water-based polyurethane wet-process base is applied to the dry release paper water-based surface, it is first preheated to 80℃-100℃, and then gradually preheated to 120℃-140℃. Then, it is subjected to embossing process to obtain embossed water-based polyurethane synthetic leather for sports and leisure shoes.

[0072] The embossed all-waterborne polyurethane synthetic leather for sports and leisure shoes prepared in this comparative example has a stiff feel, a softness of 2.0 mm, poor pattern fullness, a peel strength of 80 N / 3 cm, and a crack resistance of 50,000 flexes at room temperature, which does not meet the requirements for embossed all-waterborne polyurethane synthetic leather for sports and leisure shoes.

[0073] Comparison Case 4

[0074] This embodiment provides an embossed, water-based polyurethane synthetic leather for sports and leisure shoes, the preparation method of which includes the following steps S1-S3.

[0075] S1. Add 2% by mass of pH adjuster to waterborne polyurethane resin slurry, stir evenly to adjust the pH value of waterborne polyurethane resin slurry to neutral, then add 0.6% by mass of pre-foaming agent NaHCO3 powder, stir at a rotor speed of 1500 rpm for 30 minutes, after stirring evenly, let stand for 30 minutes to obtain a uniform and stable waterborne polyurethane coating slurry.

[0076] The preparation process of waterborne polyurethane resin slurry is as follows: Weigh 90 parts of waterborne polyurethane resin, 15 parts of deionized water, 1.6 parts of thickener, 0.5 parts of crosslinking agent, and 8 parts of waterborne color paste according to the mass ratio; after mixing the polyurethane resin, deionized water, thickener, crosslinking agent, and waterborne color paste evenly, the waterborne polyurethane resin slurry is obtained.

[0077] S2. The waterborne polyurethane coating slurry is coated onto the surface of the nonwoven fabric after waterborne slurry pretreatment, and then coagulated directly through a weak acid gradient coagulation liquid B with a concentration of 1.5wt%, resulting in a waterborne polyurethane wet-process base with poor cell structure uniformity.

[0078] S3. After the water-based polyurethane wet-process base is applied to the dry release paper water-based surface, it is first preheated to 80℃-100℃, and then gradually preheated to 120℃-140℃. Then, it is subjected to embossing process to obtain embossed water-based polyurethane synthetic leather for sports and leisure shoes.

[0079] The embossed all-waterborne polyurethane synthetic leather for sports and leisure shoes prepared in this comparative example has the following characteristics: it feels stiff, its softness is 2.2mm, its peel strength is 80N / 3CM, and its stability is poor; it cracks after 60,000 flexes at room temperature, which does not meet the requirements for embossed all-waterborne polyurethane synthetic leather for sports and leisure shoes.

[0080] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0081] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing embossed, water-based polyurethane synthetic leather for sports and leisure shoes, characterized in that, Includes the following steps: S1. After adjusting the pH value of the waterborne polyurethane resin slurry to neutral, add the pre-foaming agent, stir evenly, and let stand to obtain the waterborne polyurethane coating slurry; the pre-foaming agent is NaHCO3 powder. S2. The waterborne polyurethane coating slurry is coated onto the surface of the nonwoven fabric after waterborne slurry pretreatment. It is first coagulated by weak acid gradient coagulation liquid A, and then coagulated by weak acid gradient coagulation liquid B to obtain waterborne polyurethane wet process base. The concentration of the weak acid gradient coagulation liquid A is less than the concentration of the weak acid gradient coagulation liquid B. S3. The waterborne polyurethane wet-process base is preheated after being laminated with a dry release paper waterborne layer, and then subjected to an embossing process to obtain embossed all-waterborne polyurethane synthetic leather for sports and leisure shoes; the preheating is to first gradually heat the waterborne polyurethane wet-process base to 80℃-100℃, and then gradually heat the waterborne polyurethane wet-process base to 120℃-140℃.

2. The method for preparing embossed all-waterborne polyurethane synthetic leather for sports and leisure shoes according to claim 1, characterized in that, In step S1, the waterborne polyurethane coating slurry contains the following components in parts by mass: 85-95 parts waterborne polyurethane resin, 5-15 parts deionized water, 1-2 parts thickener, 0.2-0.5 parts crosslinking agent, 1.5-2 parts pH adjuster, 0-10 parts waterborne color paste, and 0.2-0.6 parts pre-foaming agent.

3. The method for preparing embossed all-waterborne polyurethane synthetic leather for sports and leisure shoes according to claim 1, characterized in that, In step S1, the rotor speed of the stirring device is 1000-1500 rpm, and the stirring time is 20-30 minutes.

4. The method for preparing embossed all-waterborne polyurethane synthetic leather for sports and leisure shoes according to claim 1, characterized in that, In step S1, the settling time is 20-30 minutes.

5. The method for preparing embossed all-waterborne polyurethane synthetic leather for sports and leisure shoes according to claim 1, characterized in that, In step S2, the concentration of the weak acid gradient coagulation solution A is 0.2-0.6 wt%, and the time for the first coagulation is 3-5 minutes.

6. The method for preparing embossed all-waterborne polyurethane synthetic leather for sports and leisure shoes according to claim 1, characterized in that, In step S2, the concentration of the weak acid gradient coagulation solution B is 1.2-1.6 wt%, and the second coagulation time is 3-5 minutes.

7. The method for preparing embossed all-waterborne polyurethane synthetic leather for sports and leisure shoes according to claim 1, characterized in that, In step S2, the pretreatment process of the nonwoven fabric after water-based slurry pretreatment is as follows: the nonwoven fabric base is impregnated and extruded with water-based slurry, then pre-coagulated in an oxalic acid solution with a concentration of 0.5-1.5%, and then ironed on the surface by ironing rollers to obtain the nonwoven fabric after water-based slurry pretreatment.

8. An embossed, water-based polyurethane synthetic leather for sports and leisure shoes, characterized in that, It is prepared by the preparation method described in any one of claims 1-7.