MAKING SOFT GOODS FROM A SYSTEM OF MOLDING AND PRESSING USING A SLURRY CONTAINING FIBERS

The present invention discloses a method and apparatus for molding a fibrous molded article. An aqueous slurry that contains an amount of water and a plurality of fibers is added to the molding apparatus. First and second molding screens are positioned on a first pressing unit and a second pressing unit, respectively, and include a plurality of openings. The first and second molding screens can include secondary relief features. A pressing chamber sleeve slidably engages with the first pressing unit and the second pressing unit to ensure proper alignment during molding operation. The first and second molding screens at least partially form a void that is intended to receive an amount of the aqueous slurry. The apparatus includes a heat and pressure source that removes at least some of the water from the aqueous slurry and bonds the fibers to one another resulting in the fibrous molded article.

FIELD OF THE INVENTION

The field of the invention is apparatus and method for molding a three-dimensional article and, more specifically, for molding a two- or three-dimensional article from an aqueous slurry that contains a plurality of fibers.

BACKGROUND OF THE INVENTION

The current process for creating soft goods, such as clothing, footwear (e.g., shoe uppers), bags, furniture, medical supplies, cleaning tools and consumables, toys, automotive interior parts, cases and housings for consumer electronics, and other soft goods is often wasteful and includes numerous steps. Within each manufacturing step is a separate, inefficient, labor-intensive process that often requires transport of materials between the steps. Scrap materials (e.g., cloth that is cut but not used) are 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, different equipment and processes must frequently be employed when small changes in the final design are implemented, and surface feature and/or texture final design must be added in a secondary operation. These and other shortcomings in the prior art are addressed by the present invention, as disclosed herein.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, an apparatus is provided for molding a fibrous article, the apparatus including a source for providing an aqueous slurry, a first pressing unit, a first molding screen, a second molding screen, a second pressing unit, and a pressing chamber sleeve that maintains proper alignment of the various aspects of the molding apparatus during operation. The aqueous slurry contains an amount of water and a plurality of fibers. The first and second molding screens have a plurality of openings and, optionally, a secondary relief feature. The first and second molding screens at least partially form a void that is intended to receive an amount of the aqueous slurry. The apparatus includes a heat and pressure source that removes at least some to substantially all of the water from the aqueous slurry and bonds the plurality of fibers to one another resulting in the fibrous molded article.

According to another aspect of the present invention, the openings in the first and second molding screens are preferably between 0.1 mm to approximately 50 mm in diameter and, more preferably, between 0.5 mm and approximately 10 mm in diameter, or even more preferably between 0.5 mm and 2 mm.

According to a further aspect of the invention, the secondary relief feature of the first and/or second molding screens imparts one or more features onto a surface of the solid fibrous molded article.

According to an even further aspect of the present invention, the slurry can also contain at least one of a starch, a surfactant, a water retention agent, a viscosifier, a crosslinker, a binding agent, a pH modifier and a charge modifier mixed therein.

One advantage of the present invention is the first and second molding screens can be easily designed to create a desired two- or three-dimensional shape.

Another advantage of the present invention is the first and second molding screens can be easily swapped for different molding screens with different shapes.

A further advantage of the present invention is the first and second molding screens can impart a desirable surface feature and/or texture on the solid fibrous molded part during the molding operation.

These and other advantages will be apparent to one of skill in the art in light of the present disclosure and drawings.

DETAILED DESCRIPTION OF THE INVENTION

Referring now toFIGS.1-5, one embodiment of the apparatus10of the present invention that is capable of molding an article having at least one contour, as well as at least one surface that has a texture, pattern and/or other surface characteristics desired by the end user. In the embodiment shown, the first pressing unit12, first molding screen14, second molding screen16, lower pressing unit18, a pressing chamber sleeve20, and a heating apparatus22. Common articles (or components thereof) formed using the methods and apparatus10disclosed herein include clothing, footwear (e.g., shoe uppers), bags, furniture, medical supplies, cleaning tools and consumables, toys, automotive interior parts, cases and housings for consumer electronics, and other soft goods. Examples of clothing articles include, but are not limited to, shirts, shorts, dresses, skirts, pants, socks, vests, sweaters, scarves, hats, gloves, mittens, and undergarments. Examples of bags include, but are not limited to, handbags, purses, backpacks, bookbags, 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, artificial limbs, support garments, posture correcting garments, brace supports, canes, crutches and protective coverings. The above listing of articles is intended to be exemplary and non-limiting.

The method and apparatus10of the present invention is used in conjunction with an aqueous solution that includes a plurality of fibers (“the slurry23”). The slurry23can include natural fibers, synthetic fibers or a combination thereof. Examples of natural, or biobased, 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 slurry23may additionally include starches, surfactants, water retention agents, viscosifiers, crosslinkers, binding agents, and/or pH and charge modifiers. The above listing of ingredients is intended to be exemplary and non-limiting. The molding process converts the slurry23into a solid fibrous molded part25having a desired shape and surface features by draining and/or evaporating the water from slurry23during the molding process. One suitable slurry is disclosed in U.S. patent application Ser. No. 17/466,792, the disclosure of which is hereby incorporated by reference.

An example of the aforementioned slurry may contain but is not limited to the following content: water (20-99.99%), fibers (0.0075-60%), other additives (0.0025-20%).

The slurry23can be created by combining the fibers, water and any other ingredients desired into a mixer (not shown). Once in the mixer, the ingredients are mixed until all ingredients are dispersed, and the slurry23takes on the form of a foam-like solution or homogeneous fiber dispersion.

Subsequent fiber modifiers and/or coatings to the final solid fibrous molded part25can be added that include natural or biobased waxes, latexes, and/or polyurethanes.

Referring now toFIG.1, the first pressing unit12includes a first inlet24that can be used as a port to apply either a vacuum (i.e., negative pressure) or positive pressure, or to provide airflow or heat to the interior of the apparatus10before, during or after the molding process. The first inlet24may be adapted to receive a removable adapter that may be attachable to a hose or the like that is, e.g., fluid communication with a heat, airflow, vacuum and/or positive pressure source (not shown). The first pressing unit also provides the structural stability to one side of the apparatus10enabling significant pressure (e.g, from a hydraulic device) to be applied to the slurry23during the molding process. Additional ports may be included in the first pressing unit to provide for, e.g., drainage of the water from the slurry23during the molding process. Additionally, the first pressing unit12may also include one or more slots34for receiving a heating apparatus22.

Referring now toFIGS.1and3, the first molding screen14is generally a perforated molding screen. The first molding screen14partially defines a void26in which the slurry23is molded into a solid. The first molding screen can be substantially flat or, more preferably defines a three-dimensional shape. The first molding screen may be a positive mold or a negative mold. The first molding screen14preferably includes a series of openings28that are sized to permit water to drain therethrough and/or steam to pass therethrough during the molding process. The openings28are also preferably sized to retain the fibers in the slurry23within the void as the slurry23is molded into a solid during the molding process. For example, openings28have a diameter preferably range from approximately 0.1 mm to approximately 10 mm, and openings28between approximately 0.5 mm and approximately 2 mm have been found to have particular utility. The size of the openings28may be selected based on a number of factors, including the size of the fibers in the slurry23, the amount of water necessary for draining, and the surface texture of the final molded product. The first molding screen14may also include secondary relief patterns30. In the embodiment shown the secondary relief patterns are generally shown as being hexagonal in shape. For example, the relief patterns may be raised into the void26or depressed away from the void26, or a combination thereof. In addition, the secondary relief patterns30are not limited to hexagonal and may take on any shape or shapes desired by designer. For example, the relief patterns could optionally define text on the finished molded product. The apparatus10may function with a variety of first molding screens14that can be swapped out depending on the desired final product.

Referring now toFIGS.1,2and4, the second molding screen16, like the first molding screen14, is generally a perforated molding screen. The second molding screen16partially defines the void26in which the slurry23is molded into a solid. In the embodiment shown, the first and second molding screens14,16together define the entire void26. However, in some embodiments, additional screens (e.g., a third, fourth, etc) screen may be used to also define the void26. The second molding screen16provides a corresponding (but opposite) shape to the first molding screen14such that the finished molded part has a substantially uniform cross section. Alternatively, the second molding screen16can have a completely different shape altogether from the first molding screen14, depending on the application of the material output. Similar to the first molding screen14, this second molding screen16can be changed out and customized, to exude different materials characteristics, to include (but not limited to): shape, texture, and pattern. The openings32are also preferably sized to retain the fibers in the slurry23within the void as the slurry23is molded into a solid during the molding process. For example, openings32have a diameter preferably range from approximately 0.1 mm to approximately 50 mm, and openings28between approximately 0.5 mm and approximately 10 mm have been found to have particular utility. Even more preferably, the openings are between approximately 0.5 mm and approximately 2 mm. The size of the openings32may be selected based on a number of factors, including the size of the fibers in the slurry23, the amount of water necessary for draining, and the surface texture of the final molded product. The openings32can be the same or different to the size and shape of the openings28in the first molding screen14. The secondary molding screen16may also include secondary relief patterns33similar to those described in conjunction with the first molding screen14.

The first and second molding screens14,16can be made from high-grade stainless steel, other resistant metals including Inconel types, resistant plastics such as polyoxymethylenes (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 material may also be coated to ensure better stability and/or release of the part. The first and second molding screens14,16can be 3D-printed or, for example, machined. The openings in the first and second molding screens14,16allow for fluid flow from the slurry23and drainage out of the apparatus10by way of negative or positive pressure applied during the molding process. In some embodiments, it may be necessary to include support ribs or other features (not shown) to ensure structural stability of the first and second molding screens14,16during repeated use under high temperatures and pressures.

Referring now toFIGS.1and2, the second pressing unit18includes a second inlet38that can be used as a port to apply either a vacuum or pressure, or to provide airflow or heat to the interior of the apparatus10before, during or after the molding process. The second inlet38may be adapted to receive a removable adapter that may be attachable to a hose or the like that is, e.g., fluid communication with a heat, airflow, vacuum and/or pressure source (not shown). The first pressing unit also provides the structural stability to one side of the apparatus10enabling significant pressure (e.g, from a hydraulic device) to be applied to the slurry23during the molding process. For example, hydraulic pressure of up to 1000 psi may be necessary depending on the desired end product. Additional ports may be included in the first pressing unit to provide for, e.g., drainage of the water from the slurry23during the molding process. Additionally, the second pressing unit18may also include one or more slots40for receiving a heating apparatus22.

The negative and positive pressures applied during the molding process via, e.g., the first inlet24and the second inlet38, can vary based on the needs of the particular needs of the molded product. However, in most applications, negative pressure down to 14.7 psi or positive pressures up to 500 psi may be applied via connected inlet24,38and has been shown to have particular utility.

Referring now toFIGS.1and2, the pressing chamber sleeve20at least partially surrounds the first and second pressing units12,18during operation. The pressing chamber sleeve20at least partially encloses aspects of the system, ensures proper mold and pressing alignment and ensures the apparatus10stays in alignment under significant pressure and repeated use. The pressing chamber sleeve can be made from high-grade stainless steel, other resistant metals including Inconel types, resistant plastics such as polyoxymethylenes (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 stability and/or release of the part.

Referring now toFIG.1, at least one heating apparatus22(e.g., a heating cartridge) can be utilized during typical operation of the apparatus10. In some embodiments, the heating required can be defined as wattage required to hit temperature setpoint within a given time. Typical wattage ranges from 1500 W-2500 W; however, the range may vary depending on the size of molds used, dwell time, cycle time, water content and ambient temperature. The pressure and heat can be utilized to effectively remove the desired amount of the remaining fluid (e.g., water) from the slurry23and bond the fibers to one another such that a final solid fibrous molded part25is formed. In some embodiments, it may be desirable to remove substantially all of the water from the slurry23. In other embodiments, it be desirable to tune the system maintain most, if not all, of the water in the slurry23.

Referring toFIGS.5A-G, during typical operation, a first molding screen14is positioned on the first pressing unit12and a second molding screen16is positioned on the second pressing unit18. The first and second pressing units12,18are positioned such that they are slidably engaged within the pressing chamber sleeve.

The slurry23is provided into the void26partially formed by the second molding screen16. The first pressing unit12, along with the first molding screen14, is then slid partially towards the second molding screen16and the second pressing unit18, as shown inFIG.5B. A vacuum is applied to the second inlet38such that water from the slurry23is drained and the slurry23commences dewatering. Referring now toFIG.5C, heat is applied to the first and/or second pressing units14,18via one or more heating apparatus22and pressure is also applied to the first and/or second pressing units12,18via, e.g., a hydraulic press such that the first pressing unit12continues to slide relative to the pressing chamber sleeve20towards the second pressing unit18until it reaches the pre-determined final position. The heat and pressure are applied for a pre-determined amount of time to drain and/or evaporate the water from the slurry23and to bond the fibers to one another resulting in a solid fibrous molded part25. The secondary relief patterns30and openings28,32in the first and second molding screens14,16impart a texture on the surface of the solid fibrous molded part25.

Referring now toFIGS.5D and5E, short bursts of high-pressure air are applied through the second inlet38and a negative pressure may be applied through the first inlet24. Referring now toFIG.5F, the first pressing unit12, along with the first molding screen14and the final solid fibrous molded part25are slid relative to the pressing chamber sleeve20away from the second molding screen16. Referring now toFIG.5G, a burst of high-pressure air is applied through the first inlet24to release the solid fibrous molded part25.

In some embodiments, the solid fibrous molded part25may need additional time outside the mold to dry. Additionally, some post mold forming steps may be carried out to achieve the desired shape. Optionally, additional coatings, or other secondary operations can be carried out on the final solid fibrous molded part25after removal from the apparatus.