Composite leather-like material and use thereof

Abstract

The present application relates to a kind of composite imitation leather material and its application.The composite imitation leather material of the present application, on the basis of substrate, first composite a layer of biological cellulose film, then composite organosilicon resin layer.The composite imitation leather material obtained by the present application can be widely used in making luggage, clothing, shoes, vehicles and furniture decoration, etc., has excellent performance, softness, air permeability and moisture permeability are greatly improved.

Description

Technical Field

[0001] This invention relates to the field of imitation leather technology, and in particular to a composite imitation leather material and its application. Background Technology

[0002] Imitation leather, also known as artificial leather or synthetic leather, is a product that mimics the composition and structure of natural leather and can serve as a substitute. It typically consists of a base layer and a grain layer, with both sides closely resembling leather and possessing a degree of breathability. It is widely used in the production of various clothing fabrics, shoes, boots, bags, sports materials, and decorative materials. The grain layer of imitation leather materials is a key area of ​​technological development. Early methods used polyurethane elastomer solutions, which solidified in water, displacing the solvent and creating micropores within the elastomer. These pores interconnect, forming a tough and elastic microporous layer from the surface inwards, becoming the surface layer of the imitation leather and forming a unified structure with the base layer. With technological advancements, the materials used for the grain layer have become increasingly diverse, including polyvinyl chloride, polyolefins, and polyamides. Furthermore, the base layer materials have expanded to encompass a wide variety of fabrics, such as plain weave, bleached fabric, dyed plain weave, canvas, knitted fabric, brushed fabric, recycled fabric, non-woven fabric, cotton / chemical fiber blends, and chemical fiber fabrics (e.g., nylon, nylon satin). The resulting imitation leather materials are gradually approaching the appearance and internal structure of natural leather, with other physical properties closely matching those of natural leather, while exhibiting more vibrant colors. Their room temperature folding resistance exceeds 1 million cycles, and their low-temperature folding resistance also reaches the level of natural leather.

[0003] However, previous grain-layer materials generally had certain problems, such as poor leather feel, texture, and elasticity, and limited color and pattern. In recent years, a new material, organic polymer silicon, has emerged as the grain layer. Prepared using a dry process, it produces imitation leather materials with superior feel, texture, and elasticity. Furthermore, by adjusting the material and color of the base layer, the finished product gains more color and patterns. The resulting imitation leather materials have a longer lifespan, reaching 10-15 years. Moreover, the raw materials and production processes are more environmentally friendly and pollution-free, making it an important direction for future development.

[0004] Biocellulose, also known as bacterial cellulose (BC), is a type of cellulose synthesized by certain microorganisms such as *Acetobacter*, *Agrobacterium*, and *Rhizobium*. Unlike plant cellulose, biocellulose is not a structural component of bacterial cell walls but rather a product secreted by bacteria outside the cell. It exists as independent filamentous fibers, formed by the condensation of pure glucose. It has an extremely high cellulose content and is free of impurities such as lignin and hemicellulose. Furthermore, its microfibril pattern differs significantly from that of plant cellulose. Common biocellulose-producing bacteria include *Acetobacter xylinum* and *Acetobacter xylinum*. Its ultra-high purity cellulose structure gives it a gel-like appearance and texture. Biocellulose gels exhibit high crystallinity (up to 95%) and high polymerization (DP value 2000-8000); they possess an ultra-fine network structure and tensile strength, as well as excellent water-holding capacity, high biocompatibility, and biodegradability. Currently, it is widely used in various fields such as food and medicine. Summary of the Invention

[0005] To achieve better technical results, this invention provides a composite imitation leather material and its application.

[0006] A composite imitation leather material is made by first laminating a layer of bio-cellulose membrane onto a substrate, and then laminating an organic silicone resin layer.

[0007] Organic polymer silicon materials are a new type of environmentally friendly material, odorless and non-toxic, with excellent weather resistance, electrical insulation, oxygen and light aging resistance, mildew resistance, and chemical stability. Food-grade silicon materials can be used to make products that come into direct contact with the human body, such as baby products and kitchenware. Compared with conventional organic elastomers, silicon materials are more fluid, allowing for molding, calendering, or extrusion with lower energy consumption, offering advantages such as ease of processing and high production efficiency. These superior properties make silicon material products a natural replacement for similar PVC and PU products. Polymer silicon imitation leather can replace natural leather in clothing fabrics, shoe and bag fabrics, home furnishings and furniture materials, and automotive interiors, featuring excellent leather feel, excellent elasticity, and a variety of colors and patterns. Polymer silicon imitation leather is generally made by dry-processing silicon slurry onto a base of knitted fabric, woven fabric, or non-woven fabric. However, when silicone paste is laminated with a substrate, it suffers from poor adhesion. Furthermore, when the surface is recoated, such as for color change, printing, gloss enhancement, matte finish, or moisture curing, it exhibits difficulties in wetting and spreading, and poor recoatability. These technical defects are pressing problems that need to be addressed in existing technologies. This invention first laminates a layer of bio-cellulose membrane onto a substrate, followed by a layer of silicone resin. Utilizing the unique three-dimensional network structure and abundant hydroxyl groups on the surface of the bio-cellulose membrane, the substrate, bio-cellulose membrane, and silicone resin layer not only possess physical composite properties after lamination but also exhibit certain chemical reaction characteristics, significantly improving the bonding strength. Firstly, the composite between the substrate and the bio-cellulose membrane is generally a physical composite, but the ultrafine fiber properties of the bio-cellulose membrane allow for a tighter bonding. Secondly, the bio-cellulose membrane and silicone resin layer not only have physical pressure characteristics but also a grafting effect between the active hydroxyl groups and the silicone resin, resulting in a tighter and stronger composite. Therefore, the resulting composite anti-leather material possesses superior leather properties.

[0008] Preferably, the thickness of the bio-cellulose membrane is between 0.5 mm and 30 mm, and the water content of the bio-cellulose membrane is below 35 wt%. The bio-cellulose membrane can be dehydrated by mechanical compression or hot air drying to reduce the water content to below 35 wt%, and then cut to the required thickness according to the needs of use.

[0009] The substrate includes one or more of the following: plain cloth, bleached cloth, dyed plain cloth, canvas, knitted cloth, brushed cloth, recycled cloth, non-woven cloth, cotton / chemical fiber blended cloth, and chemical fiber cloth.

[0010] The silicone resin layer is obtained by molding, calendering, or extruding silicone material. The silicone material includes one or more of vinyl silicone resin, methyl silicone resin, and methyl hydrogen silicone resin. The silicone resin layer also includes an organic solvent, a catalyst, and a crosslinking agent for dissolving the silicone material. The organic solvent includes one or more of benzene, xylene, 120# solvent, silicone oil, and dimethyl silicone oil. The silicone resin layer also includes a color paste or colorant.

[0011] Furthermore, the present invention may also contain bio-cellulose gel particles in the silicone resin layer. The bio-cellulose gel particles have a particle size between 0.01-1 mm and a content of 5-15% by weight; the bio-cellulose gel particles are obtained by static shallow-tray fermentation or dynamic fermentation to produce a hydrogel membrane, followed by dehydration, sterilization, grinding, and other treatments. The bio-cellulose gel particles and silicone material are dissolved together in an organic solvent and thoroughly stirred. Through the action of a catalyst and crosslinking agent, the mixture is molded, calendered, or extruded to obtain a silicone resin layer containing bio-cellulose gel particles. This silicone resin layer not only bonds more firmly and tightly to the underlying bio-cellulose membrane layer but also increases its surface activity, making it more suitable for subsequent surface treatments such as color modification, printing, gloss enhancement, matting, and moisture curing.

[0012] The bio-cellulose is obtained by static fermentation of bio-cellulose-producing bacteria in a fermentation medium, including *Acetobacter xylinum* or *Acetobacter xylinum*. The fermentation medium contains appropriate amounts of carbon source, nitrogen source, and trace elements. The carbon source includes one or more of glucose, sucrose, maltose, and lactose; the nitrogen source includes beef extract or peptone; and the pH of the medium is adjusted to 3.5-5.0 using glacial acetic acid or citric acid. Coconut water is preferably used as the carbon source in the fermentation medium, preferably containing 80-90% coconut water by volume.

[0013] The composite imitation leather material obtained by this invention can be widely used in the decoration of bags, clothing, shoes, vehicles and furniture, etc. It has excellent properties, and its softness, breathability and moisture permeability have been greatly improved. Detailed Implementation

[0014] To further illustrate the present invention, the following embodiments are provided for detailed explanation:

[0015] The bio-cellulose wet membrane of this invention is prepared using existing technologies, such as static shallow-tray fermentation or dynamic fermenter fermentation. One preparation method of the bio-cellulose wet membrane involved in the embodiments is as follows: A bio-cellulose fermentation medium is prepared, containing appropriate amounts of carbon sources such as glucose and sucrose, and adding appropriate amounts of nitrogen sources and trace elements. The pH is adjusted to 3.5-5.0. After sterilization, 10% (volume ratio) of fermentation bacteria is inoculated into the medium. The fermentation bacteria can be *Acetobacter xylinum* or *Acetobacter xylinum*. Fermentation is carried out at 34°C in shallow trays for 7 days, resulting in a bio-cellulose hydrogel membrane with a thickness of at least 20 mm on the surface of the shallow tray. The membrane is then rinsed with ethanol or water and set aside for use.

[0016] Example 1: Preparation of composite imitation leather material

[0017] The preparation method includes the following steps:

[0018] 1) The fermented biocellulose membrane was soaked in a 20wt% sodium hydroxide solution at 90 degrees Celsius for 6 hours;

[0019] 2) After soaking, the bio-cellulose membrane is mechanically compressed and dehydrated or dried with hot air until the moisture content is below 20wt%, and then cut into films with a thickness of 1-5mm.

[0020] 3) Prepare the base nonwoven fabric for later use;

[0021] 4) Take 60 parts of vinyl silicone resin, 25 parts of dimethyl silicone oil, 5 parts of color paste, 0.5 parts of platinum catalyst, and 10 parts of crosslinking agent trimethylolpropane. After mechanically mixing and degassing, coat the mixture onto the surface of release paper and place it in a dryer at 125-135℃ to dry and cure, thus obtaining an organosilicon resin layer.

[0022] 5) Place the non-woven fabric on the lower layer, cover it with the film from step 2), and then cover it with the silicone resin layer from step 4). Mechanically press it at 90℃-110℃ for 8-10 hours, and then cure it for 4-6 hours to obtain the imitation leather material, which is then rolled and formed into a roll.

[0023] Example 2: Preparation of composite imitation leather material

[0024] The preparation method includes the following steps:

[0025] 1) The fermented biocellulose membrane was soaked in a 15wt% potassium hydroxide solution at 80 degrees Celsius for 8 hours;

[0026] 2) After soaking, the bio-cellulose membrane is mechanically compressed and dehydrated or dried with hot air until the moisture content is below 30wt%, and then cut into films with a thickness of 6-8mm.

[0027] 3) Prepare a flat cloth as the substrate;

[0028] 4) Take 65 parts of methyl hydrogen silicone resin, 20 parts of xylene, 5 parts of color paste, 0.2 parts of organic bismuth catalyst, and 8 parts of crosslinking agent trimethylolpropane. After mechanically mixing and degassing, coat the mixture onto the surface of release paper and place it in a dryer at 125-135℃ to dry and cure, thus obtaining an organic silicone resin layer.

[0029] 5) Place the flat layer on the bottom, cover it with the film from step 2), and then cover it with the silicone resin layer from step 4). Mechanically press it at 90℃-110℃ for 8-10 hours, and then cure it for 4-6 hours to obtain the imitation leather material, roll it up and form it into a roll.

[0030] Example 3: Preparation of composite imitation leather material

[0031] The preparation method includes the following steps:

[0032] 1) The fermented biocellulose membrane was soaked in a 15wt% sodium hydroxide solution at 80 degrees Celsius for 7 hours;

[0033] 2) After soaking, the bio-cellulose membrane is mechanically compressed and dehydrated or dried with hot air until the moisture content is below 25wt%, and then cut into films with a thickness of 4-6mm.

[0034] 3) Prepare recycled fabric as the base material;

[0035] 4) The fermented biocellulose membrane is freeze-dried under vacuum for 16-18 hours, and then ultra-finely pulverized to obtain biocellulose gel particles with a particle size between 0.01-1 mm.

[0036] 5) Take 50 parts of methyl silicone resin, 24 parts of 120# solvent, 6 parts of color paste, 0.5 parts of platinum catalyst, 10 parts of the bio-cellulose gel particles from step 4), and 10 parts of crosslinking agent trimethylolpropane. After mechanically mixing and degassing, coat the mixture onto the surface of release paper and place it in a dryer at 125-135℃ to dry and cure, thereby obtaining an organosilicon resin layer containing bio-cellulose gel particles.

[0037] 6) Place the recycled material on the lower layer, cover it with the film from step 2), and then cover it with the silicone resin layer from step 5. Mechanically press it at 90℃-110℃ for 8-10 hours, and then cure it for 4-6 hours to obtain the imitation leather material, which is then rolled and formed into a roll.

[0038] Comparative Example 1:

[0039] Remove steps 1) and 2) in Example 1, and directly laminate the silicone resin layer of step 4) onto the nonwoven fabric substrate in step 5).

[0040] Comparative Example 2:

[0041] Remove steps 1) and 2) in Example 2, and in step 5), directly laminate the silicone resin layer of step 4) onto the flat fabric substrate.

[0042] Comparative Example 3:

[0043] Remove step 4 from Example 3); do not add bio-cellulose gel particles in step 5); the remaining steps are the same.

[0044] Experimental Example: Tensile strength, coating surface energy, and peel strength tests were conducted on the products described in the above embodiments. The tensile strength test method was based on standard GB / T 38612-2020, "Test Methods for Artificial Leather and Synthetic Leather: Determination of Tensile Load and Elongation at Break." Surface energy was measured using the contact angle method. The peel strength test between the coating and the base fabric was conducted in accordance with standards DIN53273, DIN53278, and DIN53357-A.

[0045] The experimental results are shown in the table below (the experimental values ​​are the average of three trials):

[0046] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Tensile strength 8.6MPa 9.2MPa 10.5MPa 4.2MPa 4.0 MPa 8.7MPa Elongation at break 560％ 530％ 670％ 350％ 320％ 550％ Surface energy <![CDATA[38mJ / m 2 ]]> <![CDATA[36mJ / m 2 ]]> <![CDATA[47mJ / m 2 ]]> <![CDATA[21mJ / m 2 ]]> <![CDATA[20mJ / m 2 ]]> <![CDATA[39mJ / m 2 ]]> Water contact angle 91° 89° 64° 132° 130° 90° Peel strength 65N / 3cm 63N / 3cm 80N / 3cm 38N / 3cm 36N / 3cm 66N / 3cm

[0047] The experimental results above show that the imitation leather material of the present invention, which incorporates a bio-cellulose membrane layer, has significantly improved tensile strength, elongation at break, surface energy, and glass strength, while the water contact angle is significantly reduced. In particular, the imitation leather material of Example 3, after adding active bio-cellulose gel particles to the silicone resin layer, exhibits even more significant improvements in various indicators. This makes the composite imitation leather material of the present invention possess outstanding and excellent properties, and it can be widely used in the decoration of bags, clothing, shoes, vehicles, and furniture.

[0048] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A composite imitation leather material, characterized in that, The material is prepared by first laminating a layer of bio-cellulose membrane onto a substrate, and then laminating an organosilicon resin layer. The preparation method includes the following steps: 1) The fermented biocellulose membrane was soaked in a 20wt% sodium hydroxide solution at 90 degrees Celsius for 6 hours; 2) After soaking, the bio-cellulose membrane is mechanically compressed and dehydrated or dried with hot air until the moisture content is below 20wt%, and then cut into films with a thickness of 1-5mm. 3) Prepare the base nonwoven fabric for later use; 4) Take 60 parts of vinyl silicone resin, 25 parts of dimethyl silicone oil, 5 parts of color paste, 0.5 parts of platinum catalyst, and 10 parts of crosslinking agent trimethylolpropane. After mechanically mixing and degassing, coat the mixture onto the surface of release paper and place it in a dryer at 125-135℃ to dry and cure, thus obtaining an organosilicon resin layer. 5) Place the non-woven fabric on the lower layer, cover it with the film from step 2), and then cover it with the silicone resin layer from step 4). Mechanically press it at 90℃-110℃ for 8-10 hours, and then cure it for 4-6 hours to obtain the imitation leather material.

2. A composite imitation leather material, characterized in that, The material is prepared by first laminating a layer of bio-cellulose membrane onto a substrate, and then laminating an organosilicon resin layer. The preparation method includes the following steps: 1) The fermented biocellulose membrane was soaked in a 15wt% potassium hydroxide solution at 80 degrees Celsius for 8 hours; 2) After soaking, the bio-cellulose membrane is mechanically compressed and dehydrated or dried with hot air until the moisture content is below 30wt%, and then cut into films with a thickness of 6-8mm. 3) Prepare a flat cloth as the substrate; 4) Take 65 parts of methyl hydrogen silicone resin, 20 parts of xylene, 5 parts of color paste, 0.2 parts of organic bismuth catalyst, and 8 parts of crosslinking agent trimethylolpropane. After mechanically mixing and degassing, coat the mixture onto the surface of release paper and place it in a dryer at 125-135℃ to dry and cure, thus obtaining an organic silicone resin layer. 5) Place the flat layer on the bottom layer, cover it with the film from step 2), and then cover it with the silicone resin layer from step 4). Mechanically press it at 90℃-110℃ for 8-10 hours, and then cure it for 4-6 hours to obtain the imitation leather material.

3. A composite imitation leather material, characterized in that, The material is prepared by first laminating a layer of bio-cellulose membrane onto a substrate, and then laminating an organosilicon resin layer. The preparation method includes the following steps: 1) The fermented biocellulose membrane was soaked in a 15wt% sodium hydroxide solution at 80 degrees Celsius for 7 hours; 2) After soaking, the bio-cellulose membrane is mechanically compressed and dehydrated or dried with hot air until the moisture content is below 25wt%, and then cut into films with a thickness of 4-6mm. 3) Prepare recycled fabric as the base material; 4) The fermented biocellulose membrane is freeze-dried under vacuum for 16-18 hours, and then ultra-finely pulverized to obtain biocellulose gel particles with a particle size between 0.01-1 mm. 5) Take 50 parts of methyl silicone resin, 24 parts of 120# solvent, 6 parts of color paste, 0.5 parts of platinum catalyst, 10 parts of the bio-cellulose gel particles from step 4), and 10 parts of crosslinking agent trimethylolpropane. After mechanically mixing and degassing, coat the mixture onto the surface of release paper and place it in a dryer at 125-135℃ to dry and cure, thereby obtaining an organosilicon resin layer containing bio-cellulose gel particles. 6) Place the recycled material on the lower layer, cover it with the film from step 2), and then cover it with the silicone resin layer from step 5. Mechanically press it at 90℃-110℃ for 8-10 hours, and then cure it for 4-6 hours to obtain the imitation leather material.