Leather is a by-product of the meat industry. After slaughter, leather is processed including cleaning, tanning, dyeing and conditioning. Tanning involves stabilizing the protein structure of the hides to make them hardwearing and long lasting. Often, chrome tannins (chemicals) are added for softness whereas vegetable tannins are added for stiffness. Next, the leather is dyed to a desired color and oils are added for a variety of effects. In some processes, the leather is placed in a tumble dryer for milling to further soften the leather or enhance texture. After, coatings, dyes, waxes, oils and printing may be added to the leather to further treat the leather.
Leather is used in a variety of products including footwear and apparel, and is also used in interior design, furniture manufacturing and in the automotive industry. Some products that use leather include coats, gloves, hats, pillows and seat coverings and upholstery. The quality and cost of these products depends on the grain or quality of the leather used to make the products. Leather has three basic grains or qualities, namely, full-grain leather, top-grain leather and corrected-grain leather. Full-grain leather is the highest quality of leather because it has not been corrected at all and showcases the natural grain of the skin which provides a very luxurious, buttery look and feel. Top-grain leather is the second-highest quality of leather as the top layer of the hide has been removed making the surface very smooth and consistent. Corrected-grain or embossed leather is corrected and fixed by experienced leatherworkers to hide all of the natural inconsistencies found in leather. An artificial grain is embossed on the top and dressed out using dyes and/or pigment (paint) making this type of leather very consistent in look and grain. Imperfections are usually sanded off and then corrected.
Artificial leather, or synthetic leather, is a material intended to substitute for leather in upholstery, clothing, footwear, and other uses where a leather-like finish is desired but genuine leather is cost prohibitive or unsuitable. Artificial leather is known under many names, including leatherette, imitation leather, faux leather, vegan leather, polyurethane leather, and pleather.
Leather and synthetic leather manufacturing involves several different processes and chemicals. High quality leather is also in demand and expensive. In addition to higher costs, the chemicals, polymers and other synthetic materials used in leather processing produces wastes in solid, liquid and gaseous form that impacts the environment. Also, genuine leather has a high impact on land, water and the environment and uses some chemicals during the tanning and finishing processes. Synthetic leather uses petroleum derived materials, i.e plastics, in their processing that is not natural and does not biodegrade, and as a result, has a very high impact on the environment.
Accordingly, there is a need for an alternative to leather that replicates the desirable qualities of leather, increases supply, and reduces the associated costs and that has less impact on the environment.
The present composite material includes a material layer applied to a substrate, such as a pile fabric or other types of substrates, to create products such as footwear and apparel, where the material layer closely resembles the look and feel of leather. More specifically, a material is made having a higher biological content that resembles leather by using a renewable, biological feedstock, i.e., bio-polymer from corn and additional plant based polymers) in a transfer coating process on various plant-based and non-plant based substrates. The result of applying this process to these various substrates provides a higher bio content material (20% to 50% in the coating and up to 50% to 85% in the entire material depending on which substrate is used) to that of any leather synthetic material. The resultant material product is an alternative to leather that has less impact on the environment.
In an embodiment, a composite material is provided for footwear where the composite material includes a substrate and a material layer applied to the substrate. The material layer includes at least two transfer coating layers and an adhesive layer that secures the material layer to the substrate.
In another embodiment, a method of making a composite material having a surface that closely resembles leather is provided and includes the steps of providing a release paper, applying a first layer of a transfer coating to the release paper, heating the first layer of the transfer coating on the release paper to at least partially cure the first layer of the transfer coating, applying a second layer of the transfer coating to the first layer, heating the second layer of the transfer coating on the release paper to at least partially cure the first and second layers of the transfer coating, applying an adhesive layer to the second layer of the transfer coating, attaching a substrate to the adhesive layer, heating the adhesive layer after attaching the substrate to at least partially cure the adhesive layer and separating the release paper from the first layer of the transfer coating.
The present disclosure is directed to a material or material layer that resembles the look and feel of leather and may be used in lieu of leather in making footwear, outerwear, apparel and other products, such as home goods. Specifically, the material layer may be used as a facing material attached to a substrate to closely approximate a liner or it may be lined and used as an outer material for several different products. In one application, the material layer is applied and attached to a substrate, such as a pile fabric or other types of substrates, to form a composite material for making footwear, coats, gloves and other products and leather.
Referring now to
Referring to
In the above embodiments, the material layer that resembles leather, includes a transfer coating applied to a release substrate such as a release paper.
The release paper supply roller 34 includes a release paper 36 provided on a roll 38 that is received from a release paper manufacturer. The release paper 36 may be any suitable paper that adds texture. As shown in
A first coating applicator 44 is located at a first end of the first oven 42 to apply a first layer of the transfer coating (
The first oven 42 heats the first layer 52 of the transfer coating 48 on the release paper 36 to a temperature of 80 to 120° C. or other suitable temperature, to at least partially cure the first layer and create a pre-skin or pre-film on the surface of the release paper 36. In an embodiment, the first layer 52 of the transfer coating 48 is completely cured (100%) in the first oven 42. A second coating applicator 58 is positioned at the second end or exit of the first oven 42 and applies a second layer 60 (
After the second coating applicator 58, the release paper 36 having the first and second layers 52, 60 of the transfer coating 48, moves through the second heater, which is second oven 64. The second oven 64 heats the first and second layers 52, 60 of the transfer coating 48 on the release paper 36 to a temperature of 150 to 160° C. to at least partially cure the first layer 52 and the second layer 60, and create a complete skin or film on the surface of the release paper 36. In an embodiment, the second layer 60 of the transfer coating 48 is completely cured (100%) in the second oven 64. The release paper 36 having the cured first and second layers 52, 60 of the transfer coating 48 exits the second oven 64 and moves to the substrate supply roller 66 and the adhesive applicator 68.
The adhesive applicator 68 includes a nozzle that is connected to a storage container or reservoir that stores an adhesive or resin. The nozzle of the adhesive applicator 68 receives the adhesive from the storage container and applies the adhesive to a surface of the second layer 60 of the transfer coating 48 prior to reaching the substrate supply roller 66. In this embodiment, the thickness of the layer of adhesive on the second layer 60 is 30 to 35 grams/square meter, but may be any suitable thickness.
After the adhesive is applied to the transfer coating 48 on the release paper 36, the release paper 36 moves to the substrate supply roller 66 as shown in
As shown, the backing material of the substrate 22 faces the material layer on the release paper 36 as the substrate (backing material) contacts the adhesive layer 74. After the substrate 22 contacts the adhesive layer 74, the composite material 20 including the joined substrate, material layer and release paper, moves between opposing press rollers 76 and a press blade 78 to at least partially press the substrate and the adhesive layer together. In this way, the surface of the substrate 22, i.e., the backing material, contacts and is at least partially pressed on and secured to the material layer via the adhesive layer 74.
After the substrate is secured to the material layer by the adhesive layer 74 to form the composite material 22, the composite material 22 having the release paper 36 moves through a third heater, which is third oven 80. The third oven 80 is heated to a temperature of 80 to 120° C. or other suitable temperature, and at least partially cures the adhesive layer 74 between the substrate 22 and the material layer 24 of the composite material 20. In an embodiment, the adhesive layer 74 is fully cured in the third oven 80. When the curing process is complete, the release paper 36 is separated and removed from the surface of the first layer 52 of the transfer coating 48 and stored on a release paper roller 82 to be used again.
After manufacturing is complete, the composite material 22 may be stored for shipping or loaded on a transportation vehicle for immediate shipping to another location, such as a warehouse or another product manufacturing facility.
In the above embodiments, the transfer coating 48 used to create the material layer attached to the substrate 22, is made of one or more biological-based materials/chemicals. The first transfer coating layer or pre-skin layer includes 40 to 50 percent biological-based materials where the total renewable content of the first layer of the transfer coating is 20% to 50%. It should be appreciated that the total renewable content of the first layer of the transfer coating varies based on the material of the substrate.
In the above embodiments, the first layer 52 of the transfer coating and the second layer 60 of the transfer coating are made with different materials. In another embodiment, the first and second layers 52, 60 of the transfer coating are made with the same material. In the illustrated embodiment, the first layer 52 of the transfer coating includes waterbourne polyurethane dispersions, which are polyurethane polymer resins dispersed in water, with a solids content of 35% to 45%; and a cross-linking agent of 4.0 to 5.0 parts per hundred parts of the resin.
The second layer 60 of the transfer coating or the skin layer includes aliphatic high solids based bio polyols made of solids with a total renewable content of 35% to 45%, and a cross-linking agent, where the amount of the cross-linking agent is calculated stoichiometrically according to the NCO percentage of the high solids. NCO is an isocyanate chemical group and refers to the Nitrogen, Carbon and Oxygen atoms of the isocyanate chemical group. The NCO % is a measure of the isocyanate content of a prepolymer or other isocyanate-containing compound measured as the weight percent of unreacted isocyanate groups in a material. In an example embodiment, the aliphatic high solids based bio polyols has a dry solids content of 95.0% to 100%, a viscosity (25° C.) of 25,000 to 50,000 mPa·s, a 100% modulus of 1.6 MPa, an ultimate tensile strength of 8.0 MPa, an elongation to break of 800% to 900%, a free NCO % of 5.0% to 6.0%, a specific gravity of 1000 to 1010 kg/cubic meter and a volatile organic content of less than 1.0%.
The adhesive layer includes an adhesive or resin made with waterbourne polyurethane dispersions having a solids content of 35% to 45% and a cross-linking agent of 4.0 to 5.0 parts per hundred parts of the resin. It should be appreciated that the adhesive layer may be any suitable adhesive or resin.
Referring to
In the illustrated embodiment, the composite material 22 is fed between the first and second rollers 86a, 86b. A finish coating 88 stored in trough 89, is applied to the second roller 86b and set at a designated thickness on the second roller by blade 90 based on a distance between the end of the blade and the second roller. The finish coating on the second roller is then applied to the biological material layer (outer surface of the composite material 20). In this way, the second roller 86b applies a finish, which may be a texture, pattern or other suitable finish, to the surface of the material layer 24 to create a desired finish. For example, the finish on the surface of the material layer 24 may be a smooth finish, grainy or pebbled finish, shiny finish or matte finish. In another embodiment, the second roller 86b may have a texture or image carrier 91 formed by open cells or recesses on the surface of the second roller, that produces a type of finish on the composite material 20.
In another embodiment, the outer surface of the first roller 86a includes an abrasive material or teeth that contact the material layer 24 to sand or buff the biological material layer and create a roughened, suede or Nubuck leather look on the surface of the material layer of the composite material 20. It should be appreciated that the surface of the first roller 86a may include any suitable material or combination of materials that contact the surface of the biological material layer 24 and create a desired finish on the surface of the biological material layer.
In another embodiment, the second roller 86b includes teeth that brush and straighten fibers on a substrate, such as a pile fabric, as the composite material 20 moves between the first and second rollers 86a, 86b. It should be appreciated that the first and second rollers 86a, 86b in the finishing process 84 may include any type of surface to achieve a desired finish on one or both sides of the composite material.
In the above embodiments, the release paper 36 is placed or stretched over a series of rollers and moves through the manufacturing process by directly contacting the rollers. In another embodiment, the release paper 36 is placed on or at least partially secured to a belt that guides the release paper through the different processes to form the composite material 20. After the finishing process is complete, the composite material 20 is shipped to another facility or transferred to a storage area and stored for shipping at a later time.
Referring to
In the above embodiment, the first layer 52 defines the touch or feel of the composite material 20 and the protective properties of the composite material. The second layer 60 defines the overall softness, handle, drape and/or flexibility to the composite material 20. In an example embodiment, the second layer 60 provides flexibility, elasticity and/or resilience to the composite material 20. Also in the illustrated embodiment, the adhesive layer 74 binds or adheres the material layer 24 to the substrate 22 and includes a reinforcement material that may be a microfiber substance or microfiber material that reinforces the composite material while improving the flexibility of the composite material. It should be appreciated that the adhesive layer may include a microfiber material or other suitable reinforcement material or combination of reinforcement materials. In an embodiment, the adhesive layer 74 provides substantial tackiness to the first layer 52 and the substrate 22 and substantial elasticity to the composite material 20 while having low penetration into the substrate 22. In another embodiment, the composite material 20 does not go to a finishing process such that a finish is not applied to the second layer 60 of the composite material.
In the above embodiment of the composite material 20, the substrate 22 is preferably a textile substrate as described above. The substrate may also be made with a Tencel™ blend such as a 100% Tencel™ material, a blend made of 60% wool and 40% Tencel™ material, recycled polyethylene terephthalate (rPET) microfiber material, recycled or reconstituted leather, cotton blends, hemp blends, 100% Tencel™ non-woven material, pineapple blends, banana (Abaca) blends, paper, cork, flax, jute, linen, ramie, repurposed or recycled wool, and a variety of additional plant-based substrates. In the above embodiments, the substrate may be a non-woven material, such as a material made by bonding loose fibers; a woven material, such as two sets of threads that are interlaced at 90 degree angles to form a fabric or cloth; a knitted material; a micro-fiber material, such as a hybrid material formed by two or more of a non-woven material, a woven material and a knitted material; and a sustainable faux fur material, such as a sliver knit material, and/or a sustainable faux fur material, such as a sliver knit material.
Referring to
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In a first step shown in
In a second step shown in
In step three of the manufacturing process shown in
While particular embodiments of the present composite material and associated manufacturing processes are shown and described, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.
Number | Date | Country | |
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63364186 | May 2022 | US |