Fabrication of flexible articles from a molding and pressing system using a fiber-containing slurry

Abstract

The present invention discloses a method and apparatus for forming a fibrous molded article. An aqueous slurry containing a quantity of water and a plurality of fibers is added to a molding apparatus. First and second forming screens are positioned on the first and second press units, respectively, and include a plurality of openings. The first and second forming screens may include secondary relief features. A press chamber sleeve slidably engages the first and second press units to ensure proper alignment during the molding operation. The first and second forming screens at least partially form a void intended to receive a quantity of the aqueous slurry. The apparatus includes heat and pressure sources that remove at least a portion of the water from the aqueous slurry and bond the fibers together to produce a fibrous molded article.

Description

[Technical Field]

[0001] Priority claims This application claims the benefit of U.S. Provisional Patent Application No. 63 / 425,763, filed November 16, 2022, which is incorporated herein by reference in its entirety.

[0002] The field of the invention is apparatus and methods for forming three-dimensional articles, and more particularly, apparatus and methods for forming two- or three-dimensional articles from an aqueous slurry containing a plurality of fibers. [Background technology]

[0003] Current processes for making flexible articles, such as clothing, footwear (e.g., shoe uppers), bags, furniture, medical supplies, cleaning tools and consumables, toys, automotive interior parts, cases and housings for home appliances, and other flexible articles, are often wasteful and involve multiple steps. Within each manufacturing step, there are separate, inefficient, labor-intensive processes, which often require the transportation of materials between steps. Scrap material (e.g., fabric that has been cut but not used) is often simply discarded, adding to the waste in the process. Additionally, raw materials are typically provided in flat shapes and must be formed into the final desired shape; when slight changes in the final design are implemented, different equipment and processes must frequently be employed; and surface features and / or textures in the final design must be added in secondary operations. These and other shortcomings in the prior art are addressed by the present invention, as disclosed herein. Summary of the Invention

[0004] According to one aspect of the present invention, an apparatus for forming a fibrous article is provided, the apparatus including a source for providing an aqueous slurry, a first press unit, a first forming screen, a second forming screen, a second press unit, and a press chamber sleeve that maintains proper alignment of various aspects of the forming apparatus during operation. The aqueous slurry contains a quantity of water and a plurality of fibers. The first and second forming screens have a plurality of openings and, optionally, secondary relief features. The first and second forming screens at least partially form a void intended to receive the quantity of aqueous slurry. The apparatus includes a heat and pressure source that removes at least a portion to substantially all of the water from the aqueous slurry and bonds the plurality of fibers together to form a fibrous molded article.

[0005] According to another embodiment of the present invention, the openings of the first and second forming screens preferably have a diameter of 0.1 mm to about 50 mm, more preferably 0.5 mm to about 10 mm, or even more preferably 0.5 mm to 2 mm.

[0006] In accordance with a further aspect of the invention, the secondary relief features of the first and / or second forming screens impart one or more features onto the surface of the solid fibrous molded article.

[0007] In accordance with a further aspect of the present invention, the slurry may also contain an admixture of at least one of starch, surfactant, water retention agent, thickener, cross-linking agent, binder, pH adjuster, and charge control agent.

[0008] One advantage of the present invention is that the first and second forming screens can be easily designed to create any desired two- or three-dimensional shape.

[0009] Another advantage of the present invention is that the first and second forming screens can be easily replaced with different forming screens having different shapes.

[0010] A further advantage of the present invention is that the first and second forming screens can impart desired surface features and / or texture to the solid fibrous molded part during the molding operation.

[0011] These and other advantages will be apparent to those skilled in the art in light of this disclosure and drawings.

[0012] These and other features of the present disclosure will be more readily understood from the following detailed description of the various aspects of the disclosure, taken in conjunction with the accompanying drawings illustrating various embodiments of the disclosure. [Brief explanation of the drawings]

[0013] [Figure 1] 1 shows an exploded perspective view of one embodiment of a molding apparatus of the present invention. [Figure 2] 1 shows a partial perspective exploded view of another embodiment of a molding apparatus of the present invention; [Figure 3] FIG. 1 illustrates a top view of one embodiment of a first forming screen. [Figure 4] FIG. 1 shows a top view of one embodiment of a second forming screen. [Figure 5A] 1 shows a series of cross-sectional schematic images of one embodiment of the molding process of the present invention. [Figure 5B] 1 shows a series of cross-sectional schematic images of one embodiment of the molding process of the present invention. [Figure 5C] 1 shows a series of cross-sectional schematic images of one embodiment of the molding process of the present invention. [Figure 5D] 1 shows a series of cross-sectional schematic images of one embodiment of the molding process of the present invention. [Figure 5E] 1 shows a series of cross-sectional schematic images of one embodiment of the molding process of the present invention. [Figure 5F] 1 shows a series of cross-sectional schematic images of one embodiment of the molding process of the present invention. [Figure 5G] 1 shows a series of cross-sectional schematic images of one embodiment of the molding process of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] 1-5, one embodiment of an apparatus 10 of the present invention is capable of forming articles having at least one contour and at least one surface with a texture, pattern, and / or other surface characteristics desired by an end user. The illustrated embodiment includes a first press unit 12, a first forming screen 14, a second forming screen 16, a lower press unit 18, a press chamber sleeve 20, and a heating device 22. Typical articles (or components thereof) formed using the methods and apparatus 10 disclosed herein include clothing, footwear (e.g., shoe uppers), bags, furniture, medical supplies, cleaning tools and consumables, toys, automotive interior parts, cases and housings for home appliances, and other flexible articles. Examples of clothing articles include, but are not limited to, shirts, shorts, dresses, skirts, pants, socks, vests, sweaters, scarves, hats, gloves, mittens, and underwear. Examples of bags include, but are not limited to, handbags, wallets, backpacks, book bags, satchels, and clutches. Examples of automotive interior parts include, but are not limited to, interior panels, interior trim, seat upholstery and covers, floor mats, dashboard panels and covers, and steering wheel covers. Examples of medical applications include slings, casts, wipes, bandages, prosthetic limbs, support garments, posture corrective garments, brace supports, canes, crutches, and protective covers. The above list of articles is intended to be illustrative and non-limiting.

[0015] The method and apparatus 10 of the present invention are used with an aqueous solution containing a plurality of fibers ("slurry 23"). The slurry 23 can include natural fibers, synthetic fibers, or a combination thereof. Examples of natural or bio-based fibers include, but are not limited to, pulp, lyocell, hemp, and wool. Examples of synthetic fibers include, but are not limited to, nylon and polyester. The slurry 23 can additionally include starch, surfactants, water retention agents, thickeners, crosslinking agents, binders, and / or pH and charge control agents. The above list of ingredients is intended to be exemplary and non-limiting. The molding process converts the slurry 23 into a solid fibrous molded part 25 having the desired shape and surface characteristics by draining and / or evaporating water from the slurry 23 during the molding process. One suitable slurry is disclosed in U.S. Patent Application Serial No. 17 / 466,792, the disclosure of which is incorporated herein by reference.

[0016] An example of the slurry may contain, but is not limited to, water (20 to 99.99%), fibers (0.0075 to 60%), and other additives (0.0025 to 20%).

[0017] Slurry 23 can be made by combining the fibers, water, and any other desired ingredients in a mixer (not shown). Once in the mixer, the ingredients are mixed until all ingredients are dispersed and slurry 23 takes the form of a foamy solution or homogenous fiber dispersion.

[0018] Subsequent fiber modifiers and / or coatings including natural or bio-based waxes, latex, and / or polyurethanes can be added to the final solid fibrous molded part 25.

[0019] Referring now to FIG. 1 , the first press unit 12 includes a first inlet 24, which can be used as a port for applying either vacuum (i.e., negative pressure) or positive pressure, or for providing airflow or heat to the interior of the apparatus 10, before, during, or after the molding process. The first inlet 24 can be adapted to receive a removable adapter, which can be attachable to, for example, a hose or the like, in fluid communication with a heat, airflow, vacuum, and / or positive pressure source (not shown). The first press unit also provides structural stability to one side of the apparatus 10 and allows for the application of significant pressure (e.g., from a hydraulic device) to the slurry 23 during the molding process. Additional ports can be included in the first press unit, for example, to provide for the evacuation of water from the slurry 23 during the molding process. Additionally, the first press unit 12 can also include one or more slots 34 for receiving a heating device 22.

[0020] Referring now to FIGS. 1 and 3, the first forming screen 14 is generally a perforated forming screen. The first forming screen 14 partially defines a cavity 26 into which the slurry 23 is formed. The first forming screen can be substantially flat, or more preferably, defines a three-dimensional shape. The first forming screen may be a positive or negative mold. The first forming screen 14 preferably includes a series of openings 28 sized to allow water to drain therethrough and / or steam to pass therethrough during the forming process. The openings 28 are also preferably sized to retain the fibers in the slurry 23 within the cavity as the slurry 23 is formed into a solid during the forming process. For example, the openings 28 preferably have a diameter ranging from about 0.1 mm to about 10 mm, with openings 28 between about 0.5 mm and about 2 mm having particular utility. The size of the openings 28 can be selected based on several factors, including the size of the fibers in the slurry 23, the amount of water required for drainage, and the surface texture of the final formed product. The first forming screen 14 can also include a secondary relief pattern 30. In the illustrated embodiment, the secondary relief pattern is shown as generally hexagonal in shape. For example, the relief pattern can be raised into the voids 26, recessed away from the voids 26, or a combination thereof. Additionally, the secondary relief pattern 30 is not limited to a hexagon and can take any shape or shapes desired by the designer. For example, the relief pattern can optionally define text on the finished formed product. The apparatus 10 can function with a variety of first forming screens 14, which can be interchanged depending on the desired final product.

[0021] Referring now to FIGS. 1, 2, and 4, the second forming screen 16, like the first forming screen 14, is generally a perforated forming screen. The second forming screen 16 partially defines a cavity 26 into which the slurry 23 is solidified. In the illustrated embodiment, the first and second forming screens 14, 16 together define the entire cavity 26. However, in some embodiments, additional screens (e.g., a third, fourth, etc.) can be used to define the cavity 26. The second forming screen 16 provides a shape corresponding to (but opposite to) the first forming screen 14 so that the finished formed part has a substantially uniform cross-section. Alternatively, the second forming screen 16 can have an entirely different shape than the first forming screen 14, depending on the intended use of the material output. Like the first forming screen 14, this second forming screen 16 can be modified and customized to elicit different material properties, including (but not limited to) shape, texture, and pattern. The openings 32 are also preferably sized to retain the fibers in the slurry 23 within the voids as the slurry 23 is solidified during the molding process. For example, the openings 32 preferably have a diameter ranging from about 0.1 mm to about 50 mm, with openings 28 between about 0.5 mm and about 10 mm having been found to have particular utility. Even more preferably, the openings are from about 0.5 mm to about 2 mm. The size of the openings 32 can be selected based on several factors, including the size of the fibers in the slurry 23, the amount of water required for drainage, and the surface texture of the final molded product. The openings 32 may be the same or different in size and shape as the openings 28 of the first forming screen 14. The secondary forming screen 16 can also include a secondary relief pattern 33 similar to that described in connection with the first forming screen 14.

[0022] The first and second forming screens 14, 16 can be made from high-grade stainless steel, other durable metals including Inconel types, durable plastics such as polyoxymethylene (e.g., Delrin®) and fluorocarbon-based polymers (e.g., Teflon™), and durable ceramics such as silicon carbide, alumina, or other materials similarly known to have suitable properties. The materials may also be coated to ensure better part stability and / or release. The first and second forming screens 14, 16 can be 3D printed or machined, for example. Openings in the first and second forming screens 14, 16 allow fluid flow from the slurry 23 and its exit from the apparatus 10 via negative or positive pressure applied during the forming process. In some embodiments, it may be necessary to include support ribs or other features (not shown) to ensure the structural stability of the first and second forming screens 14, 16 during repeated use at high temperatures and pressures.

[0023] 1 and 2, the second press unit 18 includes a second inlet 38 that can be used as a port for applying either vacuum or pressure to the interior of the apparatus 10, or for providing airflow or heat, before, during, or after the molding process. The second inlet 38 can be adapted to receive a removable adapter that can be attached to, for example, a hose or the like that is in fluid communication with a heat, airflow, vacuum, and / or pressure source (not shown). The first press unit also provides structural stability to one side of the apparatus 10 and allows for the application of significant pressure (e.g., from a hydraulic device) to the slurry 23 during the molding process. For example, hydraulic pressures of up to 1000 psi may be required, depending on the desired end product. Additional ports can be included in the first press unit, for example, to provide for the evacuation of water from the slurry 23 during the molding process. Additionally, the second press unit 18 can also include one or more slots 40 for receiving a heating device 22.

[0024] For example, the negative and positive pressures applied during the molding process via the first inlet 24 and the second inlet 38 can vary based on the particular needs of the molded product. However, in most applications, negative pressures up to 14.7 psi or positive pressures up to 500 psi may be applied via the connected inlets 24, 38 and have been shown to have particular utility.

[0025] 1 and 2, a press chamber sleeve 20 at least partially surrounds the first and second press units 12, 18 during operation. The press chamber sleeve 20 at least partially surrounds aspects of the system, ensuring proper mold and press alignment and ensuring that the apparatus 10 remains aligned under significant pressure and repeated use. The press chamber sleeve can be made from high-grade stainless steel, other durable metals including Inconel types, durable plastics such as polyoxymethylene (e.g., Delrin®), fluorocarbon-based polymers (Teflon™), or other materials known to have similar suitable properties. The material may also be coated to ensure better part stability and / or release.

[0026] Referring now to FIG. 1 , during typical operation of the apparatus 10, at least one heating device 22 (e.g., a heating cartridge) may be utilized. In some embodiments, the required heating may be defined as the wattage required to reach a temperature setpoint within a given time. Typical wattages range from 1500 W to 2500 W, although this range may vary depending on the mold size, residence time, cycle time, moisture content, and ambient temperature used. Pressure and heat may be utilized to effectively remove a desired amount of residual fluid (e.g., water) from the slurry 23 and bond the fibers together to form the final solid fibrous molded part 25. In some embodiments, it may be desirable to remove substantially all of the water from the slurry 23. In other embodiments, it may be desirable to adjust the system to retain most, if not all, of the water in the slurry 23.

[0027] 5A-5G, during typical operation, the first forming screen 14 is positioned on the first press unit 12 and the second forming screen 16 is positioned on the second press unit 18. The first and second press units 12, 18 are positioned to be slidably engaged within a press chamber sleeve.

[0028] The slurry 23 is fed into the cavity 26 partially formed by the second forming screen 16. Next, as shown in FIG. 5B, the first press unit 12, along with the first forming screen 14, is partially slid toward the second forming screen 16 and the second press unit 18. A vacuum is applied to the second inlet 38 to drain water from the slurry 23 and cause the slurry 23 to begin dewatering. Now referring to FIG. 5C, heat is applied to the first and / or second press units 14, 18 via one or more heating devices 22, and pressure is also applied to the first and / or second press units 12, 18 via, for example, a hydraulic press, so that the first press unit 12 continues to slide against the press chamber sleeve 20 toward the second press unit 18 until it reaches a predetermined final position. The heat and pressure are applied for a predetermined time to drain and / or evaporate the water from the slurry 23 and bond the fibers together to obtain a solid fibrous molded part 25. The secondary relief pattern 30 and openings 28 , 32 in the first and second forming screens 14 , 16 impart texture to the surface of the solid fibrous molded part 25 .

[0029] 5D and 5E, a short burst of high pressure air can be applied through the second inlet 38 and negative pressure can be applied through the first inlet 24. Now referring to Figure 5F, the first press unit 12, along with the first forming screen 14 and the final solid fibrous molded part 25, is slid relative to the press chamber sleeve 20 away from the second forming screen 16. Now referring to Figure 5G, a burst of high pressure air is applied through the first inlet 24 to release the solid fibrous molded part 25.

[0030] In some embodiments, the solid fibrous molded part 25 may require additional time outside the mold to dry. Additionally, several post-molding forming steps may be performed to achieve the desired shape. Optionally, additional coatings or other secondary operations may be performed on the final solid fibrous molded part 25 after removal from the apparatus.

[0031] In the following claims, corresponding structure, material, acts, and equivalents of all means-plus-function or step-plus-function elements are intended to include any structure, material, or act for performing that function in combination with other specifically claimed elements. The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure. The embodiments were chosen and described in order to best explain the principles and practical applications of the disclosure and to enable others skilled in the art to understand the disclosure in various embodiments with various modifications suitable for the particular use contemplated.

Claims

1. 1. A method for forming an article, comprising: providing an apparatus including a first forming screen and a second forming screen, the first and second forming screens combining to at least partially define a gap, the first forming screen including a plurality of openings, and the second forming screen including a plurality of openings; forming an aqueous slurry containing a quantity of water and including a plurality of fibers; adding the aqueous slurry to the space between the first forming screen and the second forming screen; Discharging at least a portion of the water from the aqueous slurry through at least one opening in at least one of the first and second forming screens; and applying heat and pressure to the aqueous slurry to remove substantially all of the water from the aqueous slurry and bond at least a portion of the plurality of fibers together to form a final solid fibrous molded part.

2. The method of claim 1 , wherein the plurality of fibers comprises at least one type of natural fiber.

3. The method of claim 1 , wherein the plurality of fibers comprises at least one type of synthetic fiber.

4. The method of claim 1 , wherein the plurality of fibers comprises at least one type of natural fiber and one type of synthetic fiber.

5. The method of claim 1 , wherein the aqueous slurry comprises at least one of a starch, a surfactant, a water retention agent, a thickening agent, a cross-linking agent, a binder, a pH adjuster, and a charge control agent.

6. The method of claim 1 , wherein the first forming screen includes a secondary relief pattern that imparts surface features on the final molded fibrous part.

7. The method of claim 1 , wherein the second forming screen includes a secondary relief pattern that imparts surface features on the final molded fibrous part.

8. 1. An apparatus for forming a fibrous molded article, comprising: a source for providing an aqueous slurry containing a quantity of water and a plurality of fibers; a first forming screen positioned on a first press unit, said first forming screen having a plurality of openings; a second forming screen positioned on the second press unit, the second forming screen having a plurality of openings; a press chamber sleeve slidably engaged with the first press unit and the second press unit; the first and second forming screens at least partially define a void intended to receive a quantity of the aqueous slurry; The apparatus includes a heat and pressure source that removes at least a portion of the water from the aqueous slurry and bonds the plurality of fibers together to result in the shaped fibrous article.

9. 9. The apparatus of claim 8, wherein the size of the openings in the first forming screen is from about 0.1 mm to about 50 mm in diameter.

10. 10. The apparatus of claim 9, wherein the size of the openings in the first forming screen is from 0.5 mm to about 10 mm in diameter.

11. 11. The apparatus of claim 10, wherein the size of the openings in the first forming screen is from 0.5 mm to about 2 mm in diameter.

12. 9. The apparatus of claim 8, wherein the size of the openings in the second forming screen is from about 0.5 mm to about 50 mm in diameter.

13. 13. The apparatus of claim 12, wherein the size of the openings in the second forming screen is from 0.5 mm to about 10 mm in diameter.

14. 14. The apparatus of claim 13, wherein the size of the openings in the second forming screen is from 0.5 mm to about 10 mm in diameter.

15. The apparatus of claim 8 , wherein the first forming screen includes at least one secondary relief feature that imparts one or more features onto a surface of a solid fibrous molded article.

16. The apparatus of claim 8 , wherein the second forming screen includes at least one secondary relief feature that imparts one or more features onto a surface of the fibrous molded article.

17. 10. The apparatus of claim 8, wherein the source for providing an aqueous slurry containing a quantity of water and a plurality of fibers also includes at least one of a starch, a surfactant, a water retention agent, a thickener, a cross-linking agent, a binder, a pH adjuster, and a charge control agent mixed therein.

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