Retractable kneaded water-based synthetic leather and preparation method thereof

Abstract

The invention belongs to the technical field of water-based synthetic leather, and particularly relates to shrinkable kneaded water-based synthetic leather and a preparation method thereof. The method comprises the following steps: S1, pre-treating base cloth; s2, firstly coating release paper with anionic waterborne polyurethane resin and drying to obtain a surface layer, then coating the surface layer with the dried anionic waterborne polyurethane resin to obtain a middle layer, finally coating the middle layer with the anionic waterborne polyurethane resin to obtain a bonding layer, and bonding the bonding layer with the pretreated base cloth to obtain a finished product; sequentially drying, shaping and stripping to obtain a semi-finished product; and S3, carrying out surface modification treatment on the surface layer of the semi-finished product, and then carrying out a water-passing grain rubbing or water rubbing process to prepare the water-based synthetic leather. According to the water-based synthetic leather prepared by the preparation method disclosed by the invention, the elasticity of the base cloth and a grain rubbing process are utilized, so that the grains of the prepared synthetic leather are more natural and irregular, closer to genuine leather and more sufficient in stereoscopic impression, and richer styles and stronger genuine leather effects are provided.

Description

Technical Field

[0001] The invention belongs to the technical field of water-based synthetic leather, and in particular relates to shrinkable kneaded water-based synthetic leather and a preparation method thereof. Background Art

[0002] With the progress of society, people's environmental awareness has gradually increased. Water-based synthetic leather produced with water-based polyurethane as raw material has gradually replaced solvent-based water-based synthetic leather produced with solvent-based PU using DMF, toluene and xylene as solvents.

[0003] At present, the method for forming textures on water-based synthetic leather is mainly to use water-based polyurethane containing polyether components to coat on release paper or emboss to form 15×10 unit blocks with a single texture, and then splice several unit blocks into a whole. Since the water-based polyurethane containing polyether components does not have shrinkage, the formed texture is dull and not three-dimensional; while the texture formed by using water-based polyurethane containing polyester components or water-based polyurethane containing polycarbonate components with certain shrinkage is single in style, making it lack of leather feel.

[0004] Therefore, there is an urgent need for a shrinkable kneaded water-based synthetic leather and a preparation method thereof to solve the above problems. Summary of the invention

[0005] In order to overcome the defects in the prior art, the present invention provides a shrinkable kneaded water-based synthetic leather and a preparation method thereof. The water-based synthetic leather prepared by the present invention has better three-dimensional sense and genuine leather sense.

[0006] To achieve one of the above purposes, the present invention adopts the following technical solution:

[0007] A method for preparing a shrinkable kneaded water-based synthetic leather specifically comprises the following steps:

[0008] S1. Fabric pretreatment: using polyvinyl alcohol aqueous solution or non-ionic water-based polyurethane resin to sequentially impregnate, stretch, dry and shape the knitted stretch fabric;

[0009] S2, first coating and drying anionic waterborne polyurethane resin on release paper to obtain a surface layer, then coating and drying anionic waterborne polyurethane resin on the surface layer to obtain a middle layer, and finally coating anionic waterborne polyurethane resin on the middle layer to obtain an adhesive layer, and laminating the adhesive layer to the pretreated base fabric, and then drying, shaping, and peeling in sequence to obtain a semi-finished product;

[0010] S3. The surface layer of the semi-finished product is subjected to surface modification treatment, and then the polyvinyl alcohol aqueous solution and water-based non-ionic polyurethane resin treated during the shaping of the base fabric are dissolved by water rubbing or water rubbing process, and the shrinkage force of the knitted stretch fabric is used to drive the overall shrinkage of the leather to obtain a water-based synthetic leather.

[0011] The steps of water kneading process are as follows:

[0012] ①. Preparation: Place the product that needs water kneading treatment into the kneading equipment;

[0013] ②. Soaking: Add appropriate amount of water and related additives to the water kneading equipment, let the product fully soak in water to make the fiber fully moist; squeeze out excess water through the rollers;

[0014] ③ Mechanical rubbing: Through the mechanical movement of the rubbing equipment, such as stirring, squeezing, rubbing, etc., the synthetic leather is repeatedly acted on to increase the softness of the product and the three-dimensionality of the texture;

[0015] ④. Temperature and time control: According to the material and requirements of the product, control the temperature and time of the process until the synthetic leather is dry and reaches the appropriate moisture content and performance.

[0016] Preferably, the stretch elastic recovery rate of the knitted stretch fabric is 85%-100%; the knitted stretch fabric is one of four-way stretch and warp-knitted suede.

[0017] Preferably, the polyvinyl alcohol aqueous solution is prepared by mixing polyvinyl alcohol and water in a mass ratio of (1-5):100; the polyvinyl alcohol in the polyvinyl alcohol aqueous solution is polyvinyl alcohol that can be dissolved at room temperature, and the model of the polyvinyl alcohol is one of 1788 and 24883.

[0018] Preferably, the solid content of the nonionic waterborne polyurethane resin is 2-10%; the nonionic waterborne polyurethane resin is a wet easily swellable resin, and the model of the waterborne nonionic polyurethane resin is one of KT7811 and KT6811.

[0019] Preferably, the stretching ratio of the stretching, drying and shaping process is ≥10%.

[0020] Preferably, the anionic waterborne polyurethane resin is one or a combination of polyester waterborne polyurethane and polycarbonate waterborne polyurethane, which reduces the elasticity of the surface layer and improves the plasticity.

[0021] Preferably, the surface modification treatment includes one or more of printing, hot stamping, polishing and lamination.

[0022] Preferably, the Young's modulus of the surface layer is 3-5 MPa, and the Young's modulus of the middle layer and the adhesive layer are both 0.8-1.2 MPa; the middle layer and the adhesive layer are both prepared by foaming and then coating, and the foaming ratio is 1.3-3.0.

[0023] Preferably, the middle layer and the adhesive layer both include 10-30% by mass of a filler, and the filler is one of kaolin and pyrophyllite powder, which can improve the supporting properties and reduce the preparation cost.

[0024] To achieve the second purpose above, the present invention provides a water-based synthetic leather prepared by a method for preparing shrinkable kneaded water-based synthetic leather, wherein the water-based synthetic leather comprises a surface layer, a middle layer, an adhesive layer and a base fabric connected in sequence.

[0025] The advantages of the present invention are:

[0026] (1) The surface layer of the water-based synthetic leather of the present invention is a coating layer, the middle layer is a foaming layer for providing hand feel and texture support, and the adhesive layer is used to bond the middle layer to the base fabric; the water-based synthetic leather prepared by the present invention utilizes the elasticity of the base fabric and the rubbing process, so that the texture of the prepared synthetic leather is more natural and irregular, closer to genuine leather, and has a stronger three-dimensional sense, providing a richer style and a stronger genuine leather effect.

[0027] (2) The preparation method of the present invention comprises the following steps: using polyvinyl alcohol aqueous solution and water-based non-ionic polyurethane resin to impregnate, widen, dry and shape knitted elastic fabric, using dry synthetic leather process to carry out veneer treatment, so as to obtain a shrinkable water-based leather semi-finished product; after surface modification treatment of the water-based leather semi-finished product, water rubbing or water rubbing process is carried out to dissolve the polyvinyl alcohol aqueous solution and water-based non-ionic polyurethane resin treated during the shaping of the base fabric, and utilizing the shrinkage force of the knitted elastic fabric to drive the overall shrinkage of the water-based leather, so as to produce a water-based synthetic leather with a three-dimensional effect. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0029] The invention discloses a shrinkable kneaded water-based synthetic leather, which consists of a surface layer, a middle layer, an adhesive layer and a base fabric which are connected in sequence.

[0030] Example 1

[0031] A method for preparing shrinkable kneaded water-based synthetic leather comprises the following steps:

[0032] S1. Weigh 2 kg of polyvinyl alcohol (model 1788), dissolve it in 100 kg of water to prepare a polyvinyl alcohol aqueous solution.

[0033] S2, take 150g / m 2 The heavy four-sided stretch base fabric is immersed in a polyvinyl alcohol aqueous solution, stretched, dried and shaped (the stretching ratio is 15%).

[0034] S3. Coat the release paper with a polyester water-based polyurethane of model KT707H, and dry it to obtain a surface layer. Coat the surface layer with a water-based polyurethane slurry of model KT750D that has been foamed twice, and dry it to obtain a middle layer. Coat the middle layer with a water-based polyurethane slurry of model KT750M to obtain an adhesive layer. Use a laminating device to laminate the adhesive layer and the treated four-sided stretch base fabric, and then dry and shape them in sequence, and finally peel them off from the release paper to obtain a semi-finished product.

[0035] S4, after the semi-finished product is subjected to surface modification treatment, it is subjected to water rubbing to obtain water-based synthetic leather 1.

[0036] The shrinkage rate of the water-based synthetic leather 1 was tested, and the radial shrinkage rate was found to be 12%, and the weft shrinkage rate was 11%.

[0037] Example 2

[0038] A method for preparing shrinkable kneaded water-based synthetic leather comprises the following steps:

[0039] S1. Select KT7811 water-based non-ionic polyurethane resin with a solid content of 5% as the base fabric treatment liquid.

[0040] S2, take 180g / m 2 The heavy warp-knitted suede is immersed in the base fabric treatment liquid, stretched, dried and shaped (the stretching ratio is 12%).

[0041] S3. Coat a polycarbonate water-based polyurethane surface layer of model number WR111 of Ketian Water-based on the release paper, and dry to obtain a surface layer, coat a water-based polyurethane slurry of model number KT650 foamed twice on the surface layer, and dry to obtain a middle layer, coat a water-based polyurethane slurry of model number KT552 on the middle layer to obtain an adhesive layer, use a laminating device to laminate the adhesive layer and the treated warp-knitted suede-like base fabric, and then sequentially dry and shape, and finally peel off from the release paper to obtain a semi-finished product.

[0042] S4, after the semi-finished product is subjected to surface modification treatment, it is subjected to a water kneading process to obtain water-based synthetic leather 2.

[0043] The shrinkage rate of the water-based synthetic leather 2 was tested, and the radial shrinkage rate was 9.6%, and the weft shrinkage rate was 8.8%.

[0044] The water-based synthetic leather prepared according to Example 1 and Example 2 can be obtained. The water-based synthetic leather prepared by the present invention has good shrinkage, so that the final texture is more natural and irregular, with a stronger three-dimensional sense and a genuine leather effect.

[0045] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing shrinkable kneaded water-based synthetic leather, characterized in that: Specifically include the following steps: S1. Fabric pretreatment: using polyvinyl alcohol aqueous solution or non-ionic water-based polyurethane resin to sequentially impregnate, stretch, dry and shape the knitted stretch fabric; S2, first coating and drying anionic waterborne polyurethane resin on release paper to obtain a surface layer, then coating and drying anionic waterborne polyurethane resin on the surface layer to obtain a middle layer, and finally coating anionic waterborne polyurethane resin on the middle layer to obtain an adhesive layer, and laminating the adhesive layer to the pretreated base fabric, and then drying, shaping, and peeling in sequence to obtain a semi-finished product; S3, performing surface modification treatment on the surface layer of the semi-finished product, and then performing water rubbing or water rubbing process to obtain water-based synthetic leather.

2. The method for preparing a shrinkable kneaded water-based synthetic leather according to claim 1, characterized in that: The stretch elastic recovery rate of the knitted stretch fabric is 85%-100%; the knitted stretch fabric is one of four-way stretch fabric and warp-knitted suede-like fabric.

3. The method for preparing a shrinkable kneaded water-based synthetic leather according to claim 1, characterized in that: The polyvinyl alcohol aqueous solution is prepared by mixing polyvinyl alcohol and water in a mass ratio of (1-5):100; the model of the polyvinyl alcohol is one of 1788 and 24883.

4. The method for preparing a shrinkable kneaded water-based synthetic leather according to claim 1, characterized in that: The solid content of the non-ionic waterborne polyurethane resin is 2-10%; the model of the waterborne non-ionic polyurethane resin is one of KT7811 and KT6811.

5. The method for preparing a shrinkable kneaded water-based synthetic leather according to claim 1, characterized in that: The stretching ratio of the stretching, drying and shaping process is ≥10%.

6. The method for preparing a shrinkable kneaded water-based synthetic leather according to claim 1, characterized in that: The anionic waterborne polyurethane resin is one or a combination of polyester waterborne polyurethane and polycarbonate waterborne polyurethane.

7. The method for preparing a shrinkable kneaded water-based synthetic leather according to claim 1, characterized in that: The surface modification treatment includes one or more of printing, hot stamping, polishing and lamination.

8. The method for preparing a shrinkable kneaded water-based synthetic leather according to claim 1, characterized in that: The Young's modulus of the surface layer is 3-5 MPa, and the Young's modulus of the middle layer and the adhesive layer are both 0.8-1.2 MPa; the middle layer and the adhesive layer are both prepared by foaming and then coating, and the foaming ratio is 1.3-3.

0.

9. The method for preparing a shrinkable kneaded water-based synthetic leather according to claim 1, characterized in that: The middle layer and the bonding layer both include 10-30% by mass of a filler, and the filler is one of kaolin and pyrophyllite powder.

10. A water-based synthetic leather obtained by the method for preparing shrinkable kneaded water-based synthetic leather according to any one of claims 1 to 9, characterized in that: The water-based synthetic leather consists of a surface layer, a middle layer, an adhesive layer and a base fabric which are connected in sequence.