Highly-conformed soft fine leather and preparation method thereof

Abstract

This invention relates to the field of synthetic leather manufacturing technology, specifically to a high-adhesion soft fine leather overlay and its preparation method; including the following steps: pretreating a microfiber base fabric; preparing a wet-process mixture, coating it onto the surface of a thin microfiber base fabric, coagulating it, washing it with water, immersing it in an oil bath, kneading it dry, and drying it to obtain a wet-process base; sequentially coating a top layer slurry, an intermediate layer slurry, and an adhesive layer slurry onto release paper, drying each layer at 70~90℃ to a semi-cured state, and then bonding it with the wet-process base; performing vacuum texturing on the overlay semi-finished product; performing crown treatment on the texturized semi-finished product, and then texturing the crowned semi-finished product; hot-pressing the texturized synthetic leather and natural split leather base layer with a polyurethane adhesive using gradient heating; after hot-pressing, using segmented air cooling for shaping, and then rolling it up to obtain the finished product; achieving an improvement in interfacial bonding strength and significantly increasing the interlayer peel strength of the leather material.

Description

Technical Field

[0001] This invention relates to the field of synthetic leather manufacturing technology, and in particular to a high-adhesion soft fine leather patch leather and its preparation method. Background Technology

[0002] Synthetic leather, with its advantages of controllable cost, standardized specifications, and stable mass production, is widely used in bags, footwear, sofas, and automotive interiors. Among them, microfiber synthetic leather has a feel close to natural leather and superior breathability and abrasion resistance compared to ordinary PVC and PU artificial leather, making it the mainstream category of high-end imitation leather materials. To further enhance the genuine leather feel of products, the industry generally adopts a composite process of bonding synthetic leather blanks with natural split leather to produce bonded leather products, balancing the structural stability of synthetic leather with the fine texture and soft touch of natural leather.

[0003] The existing method for preparing soft, fine leather bonded leather is as follows: First, ordinary wet-process microfiber backing is prepared. After the release paper is coated with a single layer or simple multi-layer polyurethane slurry and dried, it is bonded to the backing. After frequent embossing and simple kneading, a single-temperature hot-pressing process is used to bond the synthetic leather semi-finished product with the natural split leather. After hot pressing, it is naturally cooled and rolled to obtain the finished product.

[0004] In the existing methods described above, using single-temperature hot pressing cannot match the fiber structure of microfiber backing and natural split leather. The interfacial bonding between the multi-layer coating, backing, and natural split leather is weak, and the finished product is prone to bending and peeling between layers after use. Summary of the Invention

[0005] The purpose of this invention is to provide a high-adhesion soft and fine leather patch and its preparation method, aiming to solve the technical problems in the prior art where the use of single-temperature hot pressing cannot match the fiber structure of microfiber backing and natural split leather, the weak interfacial bonding force among the multi-layer coating, backing, and natural split leather, and the finished product being prone to bending and easy interlayer peeling after use.

[0006] To achieve the above objectives, the present invention employs a high-adhesion soft fine leather overlay, comprising the following raw materials: microfiber base fabric, wet-process base polyurethane resin, silicone softener, DMF solvent, ester ether copolymer polyol type polyurethane resin and polytetrahydrofuran ether diol type polyurethane resin and pigments, polyester type polyurethane resin, polyether polyurethane resin, methyl ethyl ketone solvent, yellowing-resistant polyurethane treatment agent and polyurethane bonding adhesive:

[0007] This invention also provides a method for preparing a high-adhesion soft fine leather patch, comprising the following steps:

[0008] Microfiber base fabrics with a thickness of 1.2~1.8mm were sequentially dyed, split, and sanded. After sanding, they were dried until the moisture content was ≤1%.

[0009] Prepare a wet-process mixture, coat it on the surface of a thin microfiber base fabric, and after coagulation and washing, send it into an oil bath for oiling. After oiling, remove excess oil, knead and dry it, and then dry it to obtain a wet-process base.

[0010] Top layer slurry, middle layer slurry and adhesive layer slurry are coated sequentially on the release paper. After each layer is coated, it is dried at 70~90℃ to a semi-cured state, and then bonded to the wet-process base.

[0011] The semi-finished veneer is subjected to vacuum texturing treatment at 160~200℃ and a vacuum degree of -0.06~-0.09MPa.

[0012] After the semi-finished product is textured, the crown is treated by applying a yellowing-resistant polyurethane treatment agent, and then the semi-finished product with the crown is textured at 80~120℃ for 20~40 minutes.

[0013] The textured synthetic leather and the natural split leather base layer are bonded together by gradient heating and hot pressing using polyurethane adhesive.

[0014] After hot pressing and bonding, the product is cooled and shaped by segmented air cooling, and then rolled up to obtain the finished product.

[0015] In the process of preparing a wet-process mixture, coating it onto the surface of a thin microfiber base fabric, coagulating it, washing it with water, immersing it in an oil bath, removing excess oil after immersion, kneading it dry, and finally drying it to obtain the wet-process base fabric:

[0016] The wet-process mixture is made by mixing 30-40 parts of polyurethane resin, 0.5-3.8 parts of silicone softener and 50-70 parts of DMF.

[0017] In the process of sequentially coating the release paper with a top layer slurry, an intermediate layer slurry, and an adhesive layer slurry, and drying each layer at 70-90℃ to a semi-cured state before bonding it with wet-process base material:

[0018] The topcoat slurry consists of 30-40 parts of ester-ether copolymer polyol-type polyurethane resin, 30-40 parts of polytetrahydrofuran ether diol-type polyurethane resin, and 5-10 parts of pigment; the intermediate layer slurry consists of 80-100 parts of polyester-type polyurethane resin and 20-40 parts of DMF; the adhesive layer slurry consists of 90-120 parts of polyether-type polyurethane resin and 20-35 parts of methyl ethyl ketone (MEK), wherein the topcoat slurry coating amount is 80-120 g / m². 2 The intermediate layer slurry coating amount is 150~200g / m² 2 The adhesive layer slurry coating amount is 100~150g / m². 2 .

[0019] In the step of hot-pressing the textured synthetic leather and the natural split leather base layer with polyurethane adhesive at a gradient temperature:

[0020] The temperature of the first stage is 100~120℃, the temperature of the second stage is 120~140℃, the bonding pressure is 0.3~0.6MPa, and the pressure holding time is 30~60S.

[0021] Among them, the step of using segmented air cooling to cool and shape the product after hot pressing and bonding, and then rolling it up to obtain the finished product:

[0022] The first section of cold air is 25~35℃, and the second section is 15~25℃.

[0023] Among them, the step of using segmented air cooling to cool and shape the product after hot pressing and bonding, and then rolling it up to obtain the finished product:

[0024] The air velocity for each segmented air-cooled system is 2~5m / s, and the total cooling time is 5~15min.

[0025] This invention discloses a high-adhesion soft fine leather overlay and its preparation method. First, a microfiber base fabric with a thickness of 1.2~1.8mm is sequentially dyed, split, and sanded. After sanding, it is dried until the moisture content is ≤1%. Then, a wet-process mixture is prepared and coated onto the surface of the thin microfiber base fabric. After coagulation and washing, it is immersed in an oil bath for oiling. After immersion, excess oil is removed, followed by kneading and drying to obtain a wet-process base. Next, a top layer slurry, an intermediate layer slurry, and an adhesive layer slurry are sequentially coated onto release paper. After each layer is coated, it is dried at 70~90℃ to a semi-cured state before being laminated with the wet-process base. Finally, the semi-finished overlay is heated at 160~200℃ under a vacuum of -0.0°C. Vacuum texturing is performed under pressure of 6 to -0.09 MPa; the semi-finished product after texturing is then treated with a crowning agent, and a yellowing-resistant polyurethane treatment agent is applied. The semi-finished product after crowning is then textured at 80 to 120°C for 20 to 40 minutes; subsequently, the textured synthetic leather and the natural split leather base layer are hot-pressed together using polyurethane adhesive with gradient heating; after hot-pressing, the product is cooled and shaped using segmented air cooling, and then rolled to obtain the finished product. Through the above process, the interfacial bonding strength between the multi-layer coating, wet-process base layer and natural split leather is effectively improved, the interlayer peel strength of the leather material is increased, and the problems of bending, interlayer peeling, bulging and delamination during long-term use are effectively avoided. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1This is a flowchart of the preparation method of the high-adhesion soft fine leather patch of the present invention. Detailed Implementation

[0028] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application.

[0029] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0030] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0031] This invention provides a high-adhesion soft and fine leather overlay, comprising the following raw materials: microfiber base fabric, wet-process base polyurethane resin, silicone softener, DMF solvent, ester ether copolymer polyol type polyurethane resin and polytetrahydrofuran ether diol type polyurethane resin and pigment, polyester type polyurethane resin, polyether polyurethane resin, methyl ethyl ketone solvent, yellowing-resistant polyurethane treatment agent and polyurethane bonding adhesive.

[0032] Please see Figure 1 The present invention also provides a method for preparing a high-adhesion soft fine leather patch, comprising the following steps:

[0033] S100: Microfiber base fabric with a thickness of 1.2~1.8mm is sequentially dyed, split, and sanded. After sanding, it is dried until the moisture content is ≤1%.

[0034] S200: Mix 30-40 parts of polyurethane resin, 0.5-3.8 parts of silicone softener, and 50-70 parts of DMF to prepare a wet mixture, coat it on the surface of a thin microfiber base fabric, and after coagulation and washing, send it to an oil bath for oiling. After oiling, remove excess oil, knead and dry it, and then dry it to obtain a wet base fabric.

[0035] S300: Apply top layer slurry, intermediate layer slurry and adhesive layer slurry to the release paper in sequence. After each layer is applied, dry it at 70~90℃ to a semi-cured state, and then bond it with wet-process base.

[0036] S400: Vacuum texturing treatment is performed on the semi-finished veneer at 160~200℃ and a vacuum degree of -0.06~-0.09MPa;

[0037] S500: After the semi-finished product is textured, the crown is treated and a yellowing-resistant polyurethane treatment agent is applied. Then, the semi-finished product after the crown is textured at 80~120℃ for 20~40 minutes.

[0038] S600: The textured synthetic leather and the natural split leather base layer are bonded together by gradient heating and hot pressing using polyurethane adhesive.

[0039] S700: After hot pressing and bonding, segmented air cooling is used for shaping, and the finished product is obtained by rolling after cooling.

[0040] Further, in the step of sequentially coating the release paper with a top layer slurry, an intermediate layer slurry, and an adhesive layer slurry, and drying each layer at 70~90℃ to a semi-cured state before bonding it with wet-laid substrate:

[0041] The topcoat slurry consists of 30-40 parts of ester-ether copolymer polyol-type polyurethane resin, 30-40 parts of polytetrahydrofuran ether diol-type polyurethane resin, and 5-10 parts of pigment; the intermediate layer slurry consists of 80-100 parts of polyester-type polyurethane resin and 20-40 parts of DMF; the adhesive layer slurry consists of 90-120 parts of polyether-type polyurethane resin and 20-35 parts of methyl ethyl ketone (MEK), wherein the topcoat slurry coating amount is 80-120 g / m². 2 The intermediate layer slurry coating amount is 150~200g / m² 2 The adhesive layer slurry coating amount is 100~150g / m². 2 .

[0042] Furthermore, in the step of hot-pressing the textured synthetic leather and the natural split leather base layer with polyurethane adhesive at a gradient temperature:

[0043] The temperature of the first stage is 100~120℃, the temperature of the second stage is 120~140℃, the bonding pressure is 0.3~0.6MPa, and the pressure holding time is 30~60S.

[0044] Furthermore, in the step of using segmented air cooling to cool and shape the product after hot pressing and bonding, and then rolling it up to obtain the finished product:

[0045] The first section of cold air is 25~35℃, and the second section is 15~25℃.

[0046] Furthermore, in the step of using segmented air cooling to cool and shape the product after hot pressing and bonding, and then rolling it up to obtain the finished product:

[0047] The air velocity for each segmented air-cooled system is 2~5m / s, and the total cooling time is 5~15min.

[0048] In this embodiment, a microfiber base fabric with a thickness of 1.2~1.8mm is first dyed, sheeted, and sanded sequentially. After sanding, it is dried until the moisture content is ≤1%. Then, 30~40 parts of polyurethane resin, 0.5~3.8 parts of silicone softener, and 50~70 parts of DMF are mixed to prepare a wet-process mixture, which is coated on the surface of the thin microfiber base fabric. After coagulation and washing, it is immersed in an oil bath for oiling. After immersion, excess oil is removed, and then it is kneaded and dried to obtain a wet-process base. Finally, a surface layer slurry and an intermediate layer are sequentially coated on the release paper. The topcoat and adhesive layer slurries are each applied and dried at 70-90℃ until semi-cured before being bonded to the wet-process base coat. The topcoat slurry consists of 30-40 parts of ester-ether copolymer polyol-type polyurethane resin, 30-40 parts of polytetrahydrofuran ether diol-type polyurethane resin, and 5-10 parts of pigment. The intermediate layer slurry consists of 80-100 parts of polyester-type polyurethane resin and 20-40 parts of DMF. The adhesive layer slurry consists of 90-120 parts of polyether-type polyurethane resin and 20-35 parts of methyl ethyl ketone (MEK). The topcoat slurry coating weight is 80-120 g / m². 2 The intermediate layer slurry coating amount is 150~200g / m² 2 The adhesive layer slurry coating amount is 100~150g / m². 2 Next, the semi-finished laminate is vacuum-textured at 160-200℃ and a vacuum degree of -0.06 to -0.09 MPa. After texturing, the semi-finished product undergoes crown treatment, applying a yellowing-resistant polyurethane treatment agent. The crowned semi-finished product is then textured at 80-120℃ for 20-40 minutes. Subsequently, the textured synthetic leather and natural split leather base layer are hot-pressed together using polyurethane adhesive with gradient temperature increases. The first stage temperature is 100-120℃, the second stage temperature is 120-140℃, and the bonding pressure is 0.3 MPa. The pressure is 0.6 MPa, and the holding time is 30~60s. After hot pressing and bonding, segmented air cooling is used for shaping. The first segment of cold air is 25~35℃, and the second segment of cold air is 15~25℃. After cooling, the finished product is rolled up. The air speed of each segment of air cooling is 2~5m / s, and the total cooling time is 5~15min. Through the above process, the interfacial bonding strength between the multi-layer coating, wet-process base and natural split leather is effectively improved, the interlayer peel strength of the leather is increased, and the problems of bending, interlayer peeling, bulging and delamination during long-term use are effectively avoided.

[0049] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein.

[0050] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A high-adhesion soft fine leather overlay, characterized in that, Including the following raw materials: Microfiber base fabric, polyurethane resin for wet-process baseboard, silicone softener, DMF solvent, ester ether copolymer polyol type polyurethane resin and polytetrahydrofuran ether diol type polyurethane resin and pigments, polyester type polyurethane resin, polyether polyurethane resin, methyl ethyl ketone solvent, yellowing resistant polyurethane treatment agent and polyurethane adhesive.

2. A method for preparing a high-adhesion soft fine leather overlay, as described in claim 1, characterized in that, Includes the following steps: Microfiber base fabrics with a thickness of 1.2~1.8mm were sequentially dyed, split, and sanded. After sanding, they were dried until the moisture content was ≤1%. Prepare a wet-process mixture, coat it on the surface of a thin microfiber base fabric, and after coagulation and washing, send it into an oil bath for oiling. After oiling, remove excess oil, knead and dry it, and then dry it to obtain a wet-process base. Top layer slurry, middle layer slurry and adhesive layer slurry are coated sequentially on the release paper. After each layer is coated, it is dried at 70~90℃ to a semi-cured state, and then bonded to the wet-process base. The semi-finished veneer is subjected to vacuum texturing treatment at 160~200℃ and a vacuum degree of -0.06~-0.09MPa. After the semi-finished product is textured, the crown is treated by applying a yellowing-resistant polyurethane treatment agent, and then the semi-finished product with the crown is textured at 80~120℃ for 20~40 minutes. The textured synthetic leather and the natural split leather base layer are bonded together by gradient heating and hot pressing using polyurethane adhesive. After hot pressing and bonding, the product is cooled and shaped by segmented air cooling, and then rolled up to obtain the finished product.

3. The method for preparing high-adhesion soft fine leather as described in claim 2, characterized in that, In the process of preparing a wet-process mixture, coating it onto the surface of a thin microfiber base fabric, coagulating it, washing it with water, immersing it in an oil bath for oiling, removing excess oil after immersion, kneading it dry, and finally drying it to obtain the wet-process base fabric: The wet-process mixture is made by mixing 30-40 parts of polyurethane resin, 0.5-3.8 parts of silicone softener and 50-70 parts of DMF.

4. The method for preparing high-adhesion soft fine leather as described in claim 2, characterized in that, In the process of sequentially coating the release paper with topcoat paste, intermediate paste, and adhesive paste, each layer is dried at 70-90℃ until semi-cured before being bonded to wet-laid substrate: The top layer slurry consists of 30-40 parts of ester ether copolymer polyol type polyurethane resin, 30-40 parts of polytetrahydrofuran ether diol type polyurethane resin and 5-10 parts of pigment; the intermediate layer slurry consists of 80-100 parts of polyester type polyurethane resin and 20-40 parts of DMF. The adhesive layer slurry consists of 90-120 parts polyether polyurethane resin and 20-35 parts methyl ethyl ketone (MEK), with the topcoat slurry having a coating weight of 80-120 g / m². 2 The intermediate layer slurry coating amount is 150~200g / m² 2 The adhesive layer slurry coating amount is 100~150g / m². 2 .

5. The method for preparing high-adhesion soft fine leather as described in claim 2, characterized in that, In the step of hot-pressing and bonding the textured synthetic leather to the natural split leather base layer using polyurethane adhesive with gradient temperature: The temperature of the first stage is 100~120℃, the temperature of the second stage is 120~140℃, the bonding pressure is 0.3~0.6MPa, and the pressure holding time is 30~60S.

6. The method for preparing high-adhesion soft fine leather as described in claim 2, characterized in that, After hot pressing and bonding, the product is cooled and shaped using segmented air cooling, and then rolled up to obtain the finished product: The first section of cold air is 25~35℃, and the second section is 15~25℃.

7. The method for preparing high-adhesion soft fine leather as described in claim 6, characterized in that, After hot pressing and bonding, the product is cooled and shaped using segmented air cooling, and then rolled up to obtain the finished product: The air velocity for each segmented air-cooled system is 2~5m / s, and the total cooling time is 5~15min.

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