Method of forming a material and formed product

Abstract

The present invention relates to a method of forming a material having a plurality of gaps, such as a network of voids, and a formed product formed by the method. In preferred embodiments, the material is a foam, such as a polyurethane foam. The method of forming allows the use of profile forming machining methods including computer numerical control (CNC) milling to form such materials, provided as an example only. In contrast to methods of manufacturing the formed material, such as by polymerization of a solution or emulsion of monomers, the present invention contemplates the forming of an existing (pre-formed) material having a plurality of gaps, such as a network of voids, in several aspects.

Description

Field of the Invention

[0001] The present invention relates to a molding method for a material having multiple gaps (such as a void network) and a molded product formed by the method. In a preferred embodiment, the material is a foam, such as a polyurethane foam. The molding method allows the use of a contour forming processing method including computer numerical control (CNC) milling to shape such materials, which is provided only as an example. In order to contrast with the method for manufacturing the molding material (such as by polymerization of a solution or emulsion of a monomer), the present invention considers the molding of existing (preformed) materials with multiple gaps (such as a void network) in several aspects. Background Art

[0002] Flexible foam manufacturing is the process of shaping foam into the desired end result by molding foam raw materials or casting resin systems (excluding the casting of mass-produced foam raw materials for manufacturing). Molding methods include: manual molding; and computer numerical control molding, such as CNC milling machines, lathes, milling machines, and multi-axis robotic arms.

[0003] Materials such as polyurethane foam are notoriously difficult to precisely shape. While cutting such foams with blades, saws, and the like is relatively easy, attempts to contour such foams using conventional machining methods, such as computer numerical control (CNC) methods, result in imprecise contours and a generally undesirable finish. Specifically, the inventors believe that the poor finish is caused by the machining tools deforming the foam during the molding process, resulting in cutting or even tearing the material at imprecise locations. Rather than producing a smooth surface, such machining produces a rough surface.

[0004] Despite this challenge, molded polyurethane foam is widely used for padding in seating, packaging, and more. Users often require precisely molded polyurethane products for applications such as wheelchair seating, which require custom molded products.

[0005] Few attempts have been made to overcome the problems described in this paper. Broadly speaking, previous approaches can be categorized as:

[0006] Cryogenic processes. These processes are relatively fast, accurate, and produce the desired results, but come at the expense of higher equipment costs (which must be able to withstand extreme temperatures), handling, storage, and excessive use of liquefied gaseous coolants, and exposure to the hazards of fine foam dust and liquefied gas;

[0007] • Liquid freezing. This method involves saturating the foam with water prior to freezing the water in place. Freezing is a simplified version of cryogenic processing that can allow for lower costs comparable to low temperature and dry processing by allowing the use of frozen water to maintain sufficiently low temperatures. However, this process requires the water to remain frozen throughout all stages of the forming process (which can be aided by cooling the foam and water) for optimal results. The expansion of water as it solidifies causes micro-fractures in the foam. Further, the freezing of water actually results in sub-optimal processing quality and accuracy as processing tolerances are subject to unpredictable disturbances: the expansion of water within the foam as the temperature decreases and the loss of ice melt around the forming surface as the high speed / frictional processing tool contacts the surface. Another issue with this method is the need to contain the water and the machine components must be compatible with water to avoid corrosion, electrical malfunctions, and spillage; and

[0008] • Dry processing. This method refers to techniques other than the above-mentioned low temperature and liquid freezing, and requires extended processing times, high-end equipment and tooling, and exposes the technician to harmful dust while providing only limited geometries.

[0009] Due to the limitations of these methods, especially the health hazards posed by the production of fine particles, traditional hand-forming methods remain widely used for the manufacture of foams.

[0010] In addition to the forming of soft foams, it is also common to form porous metallic materials that are generally rigid. Such materials present different problems compared to soft foams. For example, the processing of porous metallic materials produces burrs of varying sizes and shapes, depending in part on the temperature and the material used. At high temperatures, the cutting tool and the points of contact with the metal become softer, causing a tendency for the metal to plastically displace, forming smudges or burrs. Such temperatures also accelerate the dulling of the processing tool. To overcome these problems, a coolant can be used to lower the temperature of the material so that the metal hardens, resulting in cleaner cutting and preventing burrs, smudges, and related damage. Further teachings in the field of porous metal processing clarify the problem as a result of ductile shear, and solutions to smudges primarily rely on the use of cryogenic methods to achieve "brittle shear".

[0011] As in all processing methods, in the methods mentioned above, it is necessary to ensure that the material to be formed is securely fixed during the forming process. Traditionally, the material is clamped or otherwise fixed, such as by using adhesives, such as cyanoacrylate or similar "super glue" adhesives. Such techniques often damage the material due to the direct mechanical action of the clamp or due to the excessive force required to break the bond with the adhesive.

[0012] It is an object of the present invention to solve one or more of the aforementioned problems or at least to provide the skilled person with a useful choice. SUMMARY

[0013] InFirst In aspects, the present invention provides a method of shaping an elastomeric or viscoelastic material having a plurality of interstices, the method comprising the steps of:

[0014] i. providing an elastomeric or viscoelastic material having a plurality of interstices;

[0015] ii. contacting the material with an additive such that at least a portion of the additive is incorporated into at least a portion of the plurality of interstices of the material;

[0016] iii. subjecting the material to conditions such that at least a portion of the incorporated additive solidifies, hardens, and / or stiffens;

[0017] iv. shaping the material incorporating the solidified, hardened, and / or stiffened additive, thereby forming a shaped material incorporating the additive; and

[0018] v. removing at least a portion of the incorporated additive from the shaped material incorporating the additive,

[0019] wherein the additive solidifies, hardens, and / or stiffens at a temperature greater than 0 °C.

[0020] In some embodiments, the elastomeric or viscoelastic material having a plurality of interstices is an elastomeric or viscoelastic material having a network of voids.

[0021] Thus, in aspects, Second In aspects, the present invention provides a method of shaping an elastomeric or viscoelastic material having a network of voids, the method comprising the steps of:

[0022] i. providing an elastomeric or viscoelastic material having a network of voids;

[0023] ii. contacting the material with an additive such that at least a portion of the additive is incorporated into at least a portion of the network of voids of the material;

[0024] iii. subjecting the material to conditions such that at least a portion of the incorporated additive solidifies, hardens, and / or stiffens;

[0025] iv. shaping the material incorporating the solidified, hardened, and / or stiffened additive, thereby forming a shaped material incorporating the additive; and

[0026] v. removing at least a portion of the incorporated additive from the shaped material incorporating the additive,

[0027] wherein the additive solidifies, hardens, and / or stiffens at a temperature greater than 0 °C.

[0028] The method of the present invention allows for the production of shaped elastic or viscoelastic materials with a desired surface finish. The method uses additives that cure, harden, and / or stiffen at a temperature above the freezing point of water (0 °C, standard atmospheric pressure, 101.325 kPa). The additives are incorporated into the material such that the material can be shaped while the additives cure, harden, and / or stiffen, thereby preventing undesired deformation of the material during shaping.

[0029] By way of example only, in some embodiments, the additive is wax and the elastic or viscoelastic material having a plurality of voids (such as a void network) is a polyurethane foam. In those embodiments, the method may include incorporating molten wax that cures upon cooling to room temperature into the material, and then the foam can be shaped by CNC milling. At least some of the wax is then removed from the shaped foam.

[0030] Without wishing to be bound by theory, it is believed that the method of the present invention allows the material to be shaped while substantially not changing the elastic modulus of the material itself. Additionally, the additive can be selected such that the temperature difference between when the additive is in a liquid state and a solid state can be limited, such that the shrinkage (if any) of the material is very limited. Further still, by wisely adjusting the amount of additive incorporated into the material, material saturation can be avoided, thereby providing better control over potential expansion or contraction.

[0031] It is further believed that while previously disclosed cryogenic methods weaken and damage the structure of foam materials at the molecular level to enable processing, the present invention creates a mechanical advantage for the processing tool by concentrating shear forces between the high inertia of the fixed additive (especially wax) and the high momentum of the tool's rotating cutting edge.

[0032] Thus, the present invention represents a significant improvement over previously disclosed methods because it allows for the shaping of elastic or viscoelastic materials at room temperature and other temperatures above the freezing point of water. The advantages of the present invention are amplified in combination with the self-healing properties of the additives used in some embodiments - for example, any additive (such as wax) temporarily melted by the processing tool subsequently hardens after the tool has passed, thereby again contributing to the rigidity of the material. Using wax-based additives can also lubricate the machine and cutting tools to extend their service life, and doing so can simultaneously reduce the risk of electrical failures that can occur when using water in previously disclosed liquid freezing methods.

[0033] In Third aspect, the present invention provides a shaped elastic or viscoelastic material having a plurality of voids (such as a void network) prepared by the method of the first or second aspect.

[0034] In FourthIn an aspect, the present invention provides use of a solidified and / or hardened and / or rigidified additive that is solid at temperatures above 0°C to shape an elastic or viscoelastic material having a plurality of interstices, such as a network of voids, wherein the additive has been incorporated into the plurality of interstices.

[0035] In an aspect, the present invention provides a shaped elastic or viscoelastic material having a plurality of interstices, such as a network of voids, wherein at least a portion of the material has an additive incorporated into the material, wherein the additive is solidified and / or hardened and / or rigidified at temperatures above 0°C. Fifth In an aspect, the present invention provides a shaped elastic or viscoelastic material having a plurality of interstices, such as a network of voids, wherein at least a portion of the material has an additive incorporated into the material, wherein the additive is solid at temperatures above 0°C.

[0036] As used herein, the term "shaped" refers to a form that has been subjected to a shaping process.

[0037] In an aspect, the present invention provides a method of shaping an elastic or viscoelastic material having a plurality of interstices, the method comprising the steps of: Sixth In an aspect, the present invention provides a method of shaping an elastic or viscoelastic material having a plurality of interstices, the method comprising the steps of:

[0038] i. providing an elastic or viscoelastic material having a plurality of interstices;

[0039] ii. contacting the material with an additive such that at least a portion of the additive is incorporated into at least a portion of the plurality of interstices of the material;

[0040] iii. subjecting the material to conditions such that at least a portion of the incorporated additive is solidified, hardened and / or rigidified;

[0041] iv. shaping the material incorporating the solidified, hardened and / or rigidified additive, thereby forming a shaped material incorporating the additive; and

[0042] v. removing at least a portion of the incorporated additive from the shaped material incorporating the additive,

[0043] wherein the additive is not water and the additive is solidified, hardened and / or rigidified when subjected to a change in conditions selected from the group consisting of heat, magnetism, electricity, chemistry and / or electromagnetism.

[0044] In an aspect, the present invention provides a method of shaping an elastic or viscoelastic material having a network of voids, the method comprising the steps of: Seventh In an aspect, the present invention provides a method of shaping an elastic or viscoelastic material having a network of voids, the method comprising the steps of:

[0045] i. providing an elastic or viscoelastic material having a network of voids;

[0046] ii. contacting the material with an additive such that at least a portion of the additive is incorporated into at least a portion of the network of voids of the material;

[0047] iii. subjecting the material to conditions such that at least a portion of the incorporated additive solidifies, hardens and / or stiffens;

[0048] iv. shaping the material incorporating the solidified, hardened and / or stiffened additive, thereby forming a shaped material incorporating the additive; and

[0049] v. removing at least a portion of the incorporated additive from the shaped material incorporating the additive,

[0050] wherein the additive is not water and solidifies, hardens and / or stiffens when subjected to a change in conditions selected from heat, magnetism, electricity, chemistry and / or electromagnetism.

[0051] In some embodiments, the elastic or visco-elastic material having a plurality of interstices is an elastic or visco-elastic material having a network of voids.

[0052] In Eighth Aspects, the present invention provides a method of shaping an elastic or visco-elastic material having a network of voids, the method comprising the steps of:

[0053] i. providing an elastic or visco-elastic material having a network of voids;

[0054] ii. contacting the material with an additive, such that at least a portion of the additive is incorporated into at least a portion of the network of voids of the material;

[0055] iii. subjecting the material to conditions such that at least a portion of the incorporated additive solidifies, hardens and / or stiffens;

[0056] iv. shaping the material incorporating the solidified, hardened and / or stiffened additive, thereby forming a shaped material incorporating the additive; and

[0057] v. removing at least a portion of the incorporated additive from the shaped material incorporating the additive,

[0058] wherein the additive solidifies, hardens and / or stiffens when subjected to a change in conditions selected from magnetism, electricity, chemistry and / or electromagnetism.

[0059] In Ninth Aspects, the present invention provides a shaped elastic or visco-elastic material having a plurality of interstices, such as a network of voids, prepared by the method of the fifth or sixth aspect.

[0060] In TenthIn aspects, the present invention provides use of an additive to shape an elastic or viscoelastic material having a plurality of interstices, such as a network of voids, the additive having been incorporated into the plurality of interstices material, wherein the additive cures, hardens and / or stiffens when subjected to a change in a condition selected from the group consisting of magnetic, electric, chemical and / or electromagnetic.

[0061] In aspects, the present invention provides a shaped elastic or viscoelastic material having a plurality of interstices, such as a network of voids, wherein at least a portion of the material has an additive incorporated into the material, wherein the additive cures, hardens and / or stiffens when subjected to a change in a condition selected from the group consisting of magnetic, electric, chemical and / or electromagnetic. Eleventh In aspects, the present invention provides a method of forming a shaped elastic or viscoelastic material having a plurality of interstices, the method comprising the steps of:

[0062] Twelfth In aspects, the present invention provides a method of forming a shaped elastic or viscoelastic material having a network of voids, the method comprising the steps of:

[0063] i. contacting an additive with a resin capable of curing to form an elastic or viscoelastic material in a container to form a mixture;

[0064] ii. degassing the mixture, such as by vacuum, and / or mixing the mixture to form a homogenous blend;

[0065] iii. curing the resin to form an elastic or viscoelastic material incorporating at least some of the additive;

[0066] iv. shaping the material incorporating the additive to form a shaped material incorporating the additive; and

[0067] v. optionally removing at least a portion of the incorporated additive from the shaped material incorporating the additive,

[0068] wherein the additive is not water, and the additive cures, hardens and / or stiffens when subjected to a change in a condition selected from the group consisting of thermal, magnetic, electric, chemical and / or electromagnetic.

[0069] In aspects, the present invention provides a method of forming a shaped elastic or viscoelastic material having a network of voids, the method comprising the steps of: Thirteenth In aspects, the present invention provides a method of forming a shaped elastic or viscoelastic material having a network of voids, the method comprising the steps of:

[0070] i. contacting an additive with a resin capable of curing to form an elastic or viscoelastic material in a container to form a mixture;

[0071] ii. degassing the mixture, such as by vacuum, and / or mixing the mixture to form a homogenous blend;

[0072] ​iii. curing the resin to form an elastic or visco-elastic material incorporating at least some of the additives;

[0073] iv. shaping the material incorporating the additives to form a shaped material incorporating the additives; and

[0074] v. optionally removing at least a portion of the incorporated additives from the shaped material incorporating the additives,

[0075] wherein the additives are not water, and solidify, harden and / or stiffen when subjected to a change in conditions selected from heat, magnetism, electricity, chemistry and / or electromagnetism.

[0076] Other aspects of the application, to be considered in all its novel aspects, will become apparent to those skilled in the art upon reading the following description of at least one embodiment provided by way of exemplification of the practical application of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0077] One or more embodiments of the application will be described below by way of example only, and without intent to limit, with reference to the following drawings in which:

[0078] Figure 1 A schematic flow chart showing the process of incorporating a wax additive in a foam material and fixing the material to a processing surface;

[0079] Figure 2 A schematic flow chart showing the process of single or double sided processing of a foam material incorporating a wax;

[0080] Figure 3 A schematic flow chart showing the process of removing at least a portion of an incorporated wax additive from a foam material;

[0081] Figure 4 A schematic flow chart showing the application of the method of the present application to a variety of shaped masses;

[0082] Figure 5 A schematic flow chart showing the method of the present application in which a solid additive is used to produce a shaped article;

[0083] Figure 6 A schematic flow chart showing a variety of embodiments of the method of the present application, including the step of contacting a foam with an additive;

[0084] Figure 7 A schematic flow chart showing the use of a container as a mould;

[0085] Figure 8 A schematic flow chart showing the process of using solid particles, powders, etc. and other additives. Optionally, these can be manipulated by external stimuli - whether solid or otherwise;

[0086] Figure 9 A schematic flow diagram of a process is shown in which the addition or removal of heat can be used to change the properties of the additive;

[0087] Figure 10 A schematic flow diagram of a process is shown in which the additive is removed. Figure 9 A schematic flow diagram of a process is shown in which the process of the additive is continued.

[0088] Figure 11 A schematic flow diagram of a process is shown in which the additive is removed.

[0089] Figure 12 And 13 A schematic flow diagram of a process is shown in which a mold is used to create an indentation in the foam prior to CNC machining.

[0090] The figures do not necessarily represent the order of operation or any relationship between the steps on the page.

[0091] Foam is used by way of example only for illustrative purposes.

[0092] Vacuum bags are used for illustration only. Vacuum bags can be arranged in other suitable arrangements, such as sealing a suitable sheet to a solid plate or as a flexible liner secured between two solid plates to enable the sheets to be brought together under vacuum. The plates can have one or more inlets / outlets as different openings or valves; or multiple openings or valves that can be converged by a manifold.

[0093] The press can be mechanical or manual; or hand-operated; or a combination of the bag arrangement compressed mechanically or manually as described above. DETAILED DESCRIPTION

[0094] As used herein, the expression "elastic or viscoelastic" material refers to a class of materials that is:

[0095] i. deformable elastically (resilient); or

[0096] ii. substantially deformable elastically such that some energy is dissipated through the process of deforming from a first position to a second position and substantially returning to the first position (viscoelastic).

[0097] The material of the present invention comprises a solid material matrix having a plurality of interstices, such as a network of voids, therein. Examples of interstices are pores, channels, conduits, holes, interstitial spaces, etc. having one or more regions of incomplete walls. The interstices can be fluidly connected so that additives can permeate into the material, such as through the network of voids. The interstices can be arranged in an array of interstices, such as in a honeycomb material. Such interstices can or can not be fluidly connected to one or more other interstices. Nonetheless, such interstices are capable of having additives added to them and / or removed from them. Preferably, such interstices will be capable of having additives added to them And removed from them.

[0098] Thus, the material of the present invention should be distinguished from the following materials:

[0099] • are not capable of having additives added to them and / or

[0100] • are not capable of having additives removed from them and / or

[0101] • do not comprise a network of fluidly connected voids, and typically comprise a large number of discrete gas pores.

[0102] By way of example only, open cell foams are elastomeric or viscoelastic materials having a network of voids and are capable of being used in the method of the present invention, whereas closed cell foams are not elastomeric or viscoelastic materials having a network of voids and are not capable of being used in the method of the present invention.

[0103] As used herein, "interstitial" refers to a space within a material that can, for example, be filled with a gas, a liquid, or some other material other than the elastomeric or viscoelastic material. An interstitial is typically a small space, but can still be, for example, filled with a gas, a liquid, or some other material other than the elastomeric or viscoelastic material. An interstitial can be regularly shaped or irregularly shaped. Interstitials can be the same size or different sizes. For example, in a foam, the interstitials typically consist of a series of spaces of different sizes. The size of any given interstitial can be measured in a number of ways, including the smallest, largest, or average linear dimension. It can be convenient to measure the size of one or more interstitials by the average linear dimension across 2 or more axes, such as 2 orthogonal axes. The lower limit on the size is typically only limited by the ability of a gas, a liquid, or some other material other than the elastomeric or viscoelastic material to penetrate at least a portion of the interstitial. The upper limit on the size is typically unlimited, although it would be preferred for the interstitial to have an average linear dimension up to the order of about 1000 mm, such as up to about 500 mm, such as up to about 300 mm, such as up to about 100 mm, such as up to about 50 mm, such as up to about 25 mm, such as up to about 10 mm, such as up to about 5 mm, such as up to about 2 mm, such as up to about 1 mm. In some embodiments, the interstitial will be at least the order of 0.001 mm in size, such as at least 0.01 mm in size, such as at least 0.1 mm in size. It will be appreciated that a number of techniques can be used to form a material, such as an emulsion of polyurethane, having a plurality of interstitials. Such techniques will typically result in a material having interstitials with a distribution of sizes. Thus, in some embodiments, the size limitations described herein will apply to at least 60% of the interstitials, such as at least 70% of the interstitials, such as at least 80% of the interstitials, such as at least 90% of the interstitials, such as at least 95% of the interstitials. In some embodiments, the size limitations described herein will apply to 100% of the interstitials.

[0104] As used herein, a plurality means two or more. Typically, the elastomeric or viscoelastic material will not only have a plurality of interstitials, but will have at least several (3) interstitials, such as a large number of interstitials. The elastomeric or viscoelastic material can have at least 5, such as at least 10, such as at least 20, such as at least 50, such as at least 100, such as at least 500, such as at least 1000 interstitials.

[0105] As used herein, "void" refers to a space within a material that can be, for example, filled with a gas, a liquid, or some other material other than the elastomeric or viscoelastic material. A void is typically a small space, but can still be, for example, filled with a gas, a liquid, or some other material other than the elastomeric or viscoelastic material. Voids can be regularly shaped or irregularly shaped. Voids can be the same size or different sizes. For example, in a foam, the voids typically consist of a series of spaces of different sizes. The size of any given void can be measured in a variety of ways, including the smallest, largest, or average linear dimension. It can be convenient to measure the size of one or more voids by the average linear dimension across 2 or more axes, such as 2 orthogonal axes. The lower limit on size is typically only limited by the ability of a gas, a liquid, or some other material other than the elastomeric or viscoelastic material to penetrate into at least a portion of the void or voids. The upper limit on size is typically unlimited, although it would be preferred for a void to have an average linear dimension of up to about 1000 mm, such as up to about 500 mm, such as up to about 300 mm, such as up to about 100 mm, such as up to about 50 mm, such as up to about 25 mm, such as up to about 10 mm, such as up to about 5 mm, such as up to about 2 mm, such as up to about 1 mm. In some embodiments, the voids will be at least 0.001 mm in size, such as at least 0.01 mm in size, such as at least 0.1 mm in size. It will be appreciated that a variety of techniques can be used to form a material having a network of voids, such as emulsion polymerization of polyurethane. Such techniques will typically result in a material having voids with a distribution of sizes. Thus, in some embodiments, the size limitations described herein will apply to at least 60% of the voids, such as at least 70% of the voids, such as at least 80% of the voids, such as at least 90% of the voids, such as at least 95% of the voids. In some embodiments, the size limitations described herein will apply to 100% of the voids.

[0106] It will be appreciated that not all of the voids in the inventive material need to be in fluid communication with one another. It is sufficient for the purposes of the present invention that a substantial fraction (such as at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%) of the voids are in fluid communication with one another. Thus, the term "void network" as used herein refers to a substantial fraction (such as at least 10%) of the voids being in fluid communication with one another. Typically at least 50% (such as at least 60%, at least 70%, at least 80%, at least 90%) of the voids are in fluid communication with one another.

[0107] An example of a material having a plurality of interstices, where each interstice is not necessarily a hole that is interconnected to the others, but is otherwise the same as the more widely networked interstitial material just described above, is a flexible, elongated cellular material that is open celled but where additives do not readily (or at all) pass from one cell to another. This is a common material and can be used as a replacement for conventional flexible polyurethane foam. Another example can be gill-like or similar to a soft, flexible heat sink, such that it includes numerous elongated members (such as plates, leaves, or rods). In such examples, the material can have interstices (between the elongated members) but no substantial interconnection between the interstices.

[0108] Other such materials having a plurality of interstices of the present invention can be described as brush-like in appearance, where the material has parallel or linear filaments (and can be fixed at one or both ends). For example, a material having the appearance of a dense silicone brush can be formed using the disclosed invention. The purpose of doing so can be to prototype or produce small batches of a form-fitting brush, or various vibration dampening and cushioning systems.

[0109] It should be understood that the present invention is based in part on the ability of an additive to penetrate into a material through interstices, such as interstices. Thus, the interstices, such as interstices, are limited only by the requirement that the additive can penetrate into the material through the interstices, such as interstices, to a degree sufficient to enable the methods of the present invention to be performed, in terms of size and other properties, including the chemical and / or physical properties of the matrix surrounding the material.

[0110] Materials having a plurality of interstices, such as networks of interstices, can be formed in a variety of ways, including in some embodiments by incorporating a blowing agent, such as sodium bicarbonate, into the material such that the blowing agent releases a gas when the material is subjected to certain conditions, such as heating. Examples of such materials having a plurality of interstices, such as networks of interstices, include foams, batts, lattices, scaffolds, rolls, meshes, and webs. Preferably, the materials of the present invention are foams, and it is convenient to describe the present invention with respect to foams (for illustrative purposes only), although it should be understood that the general principles described herein can be applied to all elastic or viscoelastic materials having a plurality of interstices, such as networks of interstices. The foams can be formed at least in part, if not entirely, from natural or synthetic polymers.

[0111] It will be appreciated that there are a number of known materials that have a plurality of interstices that are neither elastic nor visco-elastic (such as a network of voids). Such materials include: ceramic foams, metal foams, rigid foams (e.g. expanded polystyrene (EPS) and extruded polystyrene (XPS)), and rigid grade foams (e.g. rigid polyurethane (PU), rigid melamine foam). The present invention does not consider such materials, for reasons explained below, including that the method of the present invention can advantageously exploit the elastic or visco-elastic properties of the material to incorporate the additive. Without these properties, it is more difficult to achieve incorporation of the additive and subsequent removal.

[0112] It will be appreciated that the material should preferably be chosen to be substantially resistant to the physical and / or chemical conditions experienced in the method of the present invention.

[0113] As used herein, the term "additive" refers to a component that is different from the elastic or visco-elastic material and that can be incorporated within at least a portion of the plurality of interstices (such as a network of voids) of the material. Examples of additives include:

[0114] • waxes or wax-like compounds and mixtures thereof. The wax can preferably be water-insoluble. The wax-like compounds can be water-soluble, such as PEG, panthenol, wax-like emulsifiers and mixtures thereof;

[0115] • crystalline solids / supersaturated liquids (e.g. supersaturated solutions that are stable at room temperature (e.g. sodium acetate trihydrate or similar); supersaturated solutions that are not stable at room temperature but require less heat to remain liquid than, for example, pure molten sucrose; crystalline materials in a molten state that crystallise on cooling (such as sucrose) (this example can also include one or more modifiers to lower the melting point)). Salts and sugar alcohols can be used. Eutectics of sugar alcohols and other mixtures can also be used;

[0116] • liquid crystal compounds (e.g. electro-active liquids that self-assemble to form a harder material and provide some electrical resistance, such as electro-active materials consisting of a solution containing amphiphilic mesogens that can gel or stiffen in response to an electrical stimulus and can be reversible if removed without dissolving in water);

[0117] • solidified non-Newtonian compounds, including those that solidify in resistance to processing (e.g. corn starch and water that stiffen in response to applied shearing forces - such examples can also benefit from applied sonic vibrations; corn starch and oil as an electro-rheological liquid that stiffens on application of an electrical stimulus). Advantages are control of airborne particulates and the apparent self-healing of some such materials that are able to flow into previously cut interstices (such as voids);

[0118] • Particles / powders / other solids (e.g. iron-containing powders or particles (e.g. iron powder) that can flow into some material with multiple interstices (such as a network of voids) and then form a quasi-solid when a magnetic stimulus is applied (friction between the particles and the foam will essentially lock them in place). Such powders / particles can be removed by gravity and / or acoustic agitation, optionally in combination with magnetic forces and / or in a liquid to enhance this action). Generally, the advantage of using powders or particles with magnets is that the powders or particles can be easily separated from the waste material.

[0119] • Particles / powders / other solids that can flow into some material with multiple interstices (such as a network of voids) without any magnetic influence or other change in conditions. For example, a foam can be fixed in a container with walls; and an additive powder is agitated into the multiple interstices (such as a network of voids) of the foam and any space between the foam and the container walls; thus, the foam with the powder additive is placed in a filled and supported state so that the foam and the additive can be shaped; before the shaped foam is agitated (such as after being removed from the container) to remove the powder additive. The nominal advantage of using particles / powders / other solids that can flow into some material with multiple interstices (such as a network of voids) is that energy requirements can be reduced without the need for a lot of heating because the powder can be shaken in and out or melted out if needed; faster processing times because the additive does not need to cool; little change in the size of the filled foam and empty foam because of no thermal expansion;

[0120] • Particles / powders / other solids that can undergo a state change, such as meltable. In such examples, the particles / powders / other solids can flow into some material with multiple interstices (such as a network of voids). For example, a foam can be fixed in a container with walls; an additive powder is agitated into the multiple interstices (such as a network of voids) of the foam and any space between the foam and the container walls; thus, the foam with the powder additive is placed in a filled and supported state so that the foam and the additive can be shaped; before the shaped foam is agitated (such as after being removed from the container) to remove the powder additive, applying heat to the filled and supported foam will melt the particles / powders / other solids on the outer surface of the composite and create a partial or complete seal of the particles / powders / other solids and the foam composite. For example, likewise, the bottom surface can be melted to adhere to the work surface. The nominal advantage of using particles / powders / other solids that can flow into some material with multiple interstices (such as a network of voids) is that energy requirements can be reduced without the need for a lot of heating because the powder can be shaken in and out or melted out if needed; faster processing times because the additive does not need to cool; little change in the size of the filled foam and empty foam because of no thermal expansion;

[0121] • can be hardened or arranged and oriented as a more rigid liquid by other means (e.g., ferrofluids; liquids that harden in response to a stimulus and revert to a liquid in the absence of the stimulus; starch solutions that dry out or heat-set; proteins such as gelatin / collagen that exist as a solution which then intermolecularly gel).

[0122] Preferably, the additive is a wax or a waxy compound.

[0123] As used herein, the expression "wax or waxy compound" refers to a compound that is sufficiently solidified, hardened, and / or stiffened above the freezing point of water (0°C, standard atmospheric pressure, 101.325 kPa) to facilitate the practice of the methods of the present invention capable of producing a desired shaped material, but melts or softens at temperatures above about 60°C (such as above about 50°C, such as above about 40°C) without decomposing. More generally, a "wax or waxy compound" refers to a compound that is generally solid, hardened, and / or stiffened above 15°C (such as above 20°C), but melts or softens at temperatures above about 60°C (or above about 50°C, or above about 40°C) without decomposing. By way of example only, such a wax or waxy compound is an oily additive that flows at >25°C, becomes almost a gel at slightly below 25°C, and at any temperature below this temperature can be considered processable (even if of poor quality) but cooling below 0°C improves the processing results. An example of such an oily additive is a partially hydrogenated oil that is pasty or gel-like at 25°C, but becomes flowable above this temperature so that it can penetrate a foam. Such an additive remains stable in a foam at 25°C, and as the temperature is lowered it can provide more and more processable results. Below 0°C, it can be as stiff as a solid paraffin at 25°C. In comparison to water, such an oily additive is sufficiently inhibited in the foam voids above the freezing point of the additive, including at the processing temperature of 25°C.

[0124] Waxes are generally organic in nature (typically aliphatic hydrocarbons) and are not soluble in water at room temperature. Waxes can be water-wettable and can form creams, gels, and / or pastes in some solvents such as non-polar organic solvents. Waxes can be soluble in some non-polar organic solvents, often requiring heating. Waxes can spontaneously emulsify in the presence of some liquids to form microemulsions, and / or can form emulsions with some liquids in the presence of one or more surfactants.

[0125] Waxes can have a melting point ranging from about 40°C to about 150°C. In this sense, melting can also occur below 40°C to a sufficient extent to facilitate incorporation into a plurality of interstices (such as a void network) of a material. It should be appreciated that incorporation can be achieved while only a portion of the wax is substantially liquid, e.g., the remaining portion is microcrystalline.

[0126] Waxes can also be defined by viscosity. Viscosity measures the internal flow resistance of a material, with materials having high viscosity considered to be "thicker" and less flowable than materials having low viscosity. The melt viscosity of waxes can range from low to high, and is generally dependent on the molecular weight, crystallinity, and whether the wax is oxidized or copolymerized. Increasing the molecular weight and density of a wax increases the melt viscosity of the wax, and increasing the crystallinity of a wax decreases the melt viscosity. The brittleness of a wax, i.e., its affinity for reduced particle size under mechanical force, increases with higher crystallinity and decreases with increasing density and molecular weight of the wax. The melt viscosity of waxes above their melting point is generally low.

[0127] Suitable waxes include natural and synthetic waxes. Suitable waxes can include:

[0128] • animal waxes (such as beeswax, Chinese wax, shellac wax, whale wax, and wool wax (lanolin));

[0129] • vegetable waxes and hydrogenated vegetable oils (such as wax from bayberry, carnauba, castor, esparto grass, Japan, jojoba, ouricury, rice bran, soybean, and hydrogenated oils - especially those that are pastes / oils at room temperature);

[0130] • mineral waxes (such as ceresine, montan wax, ozokerite, and peat wax);

[0131] • petroleum waxes (such as paraffin wax and microcrystalline wax); and

[0132] • synthetic waxes (such as polyolefin waxes, including polyethylene and polypropylene waxes, wax grade polytetrafluoroethylene waxes (PTFE wax grade), Fischer-Tropsch waxes, stearic amide waxes (including ethylene bis-stearamide waxes), polymerized a-olefin waxes, substituted amide waxes (e.g., esterified or saponified substituted amide waxes), polyethers (such as polyethylene glycol, such as PEG 2000), and other chemically modified waxes such as PTFE modified polyethylene waxes)

[0133] and combinations of the above. Among these, preferred waxes include hydrogenated vegetable waxes (such as carnauba wax and soy wax) and polyethers (such as polyethylene glycol). The solid portion of hydrogenated vegetable oils and lanolin are particularly preferred as they provide environmental and sustainability benefits to the methods and products of the present invention. Additionally, paraffin wax, microcrystalline wax, and various synthetic waxes are preferred.

[0134] It should also be understood that many other additives such as sugars, sugar alcohols, salts, iron powder are also preferred from an environmental / sustainability / resource-recyclability perspective.

[0135] Other examples of additives include dry iron-containing powders or compositions containing iron-containing particles (such as colloids) whose properties can be modulated by magnetic stimulation, thereby oriented in such a way to stiffen the foam upon incorporation. Other examples of additives include: non-Newtonian materials that stiffen in response to stimuli such as high-frequency mechanical waves; or liquid crystals that align into a stiffened state under electrical stimulation. These examples can allow for modulation of the properties of the additive and increase the ease of removal of the additive.

[0136] Specific examples of additives that have been tested in the processes described herein include the following, listed with perceived advantages:

[0137] • PEG 1000-3000 - Stiffness, processability, reduction of particles in air, melting point, water solubility

[0138] • PEG 3000-20000 - Stiffness, processability, reduction of particles in air, melting point, water solubility

[0139] • Paraffin - Stiffness, processability, reduction of particles in air, melting point

[0140] • Additives with additional qualities related to sustainability, renewability, environmental impact include the following:

[0141] • Co-crystals of erythritol / sorbitol / xylitol - Stiffness, melting point, processability, water solubility

[0142] • Glyceryl monostearate, stearic acid - Stiffness, melting point, processability, reduction of particles in air

[0143] • Sodium acetate trihydrate - Stiffness, melting point, processability, water solubility

[0144] • Soy, palm, castor wax and mixtures - Stiffness, melting point, processability, reduction of particles in air

[0145] • Isosorbide and 1,6-hexanediol - Stiffness, melting point, processability, reduction of particles in air

[0146] • Starch / water mixture - Water solubility, processability, reduction of particles in air

[0147] • Iron powder - Stiffness, processability

[0148] • If the intention is to swell a material with multiple gaps (such as a network of voids) such as a foam (such as a polyurethane) for processing, the following non-exhaustive list of additives is preferred:

[0149] o Citric acid trimethyl ester, pantoic acid lactone (racemic), bis-acetyl propenamide, nicotinic acid methyl ester - hardness, melting point, processability, water solubility

[0150] o Crotonic acid - hardness, melting point, processability, water solubility and precipitation from cold solution

[0151] As used herein, the term "contacting" in the expression "contacting the material with the additive, such that at least a portion of the additive is incorporated within at least a portion of the plurality of interstices (such as a network of voids) of the material" refers to any process that brings the material and the additive into close enough contact such that at least a portion of the additive is incorporated in this manner. Herein, the term "portion" can refer to at least 5%, such as at least 10%, such as at least 15%, such as at least 20%, such as at least 25%, such as at least 30%, such as at least 35%, such as at least 40%, such as at least 45%, such as at least 50%, such as at least 55%, such as at least 60%, such as at least 65%, such as at least 70%, such as at least 75%, such as at least 80%, such as at least 85%, such as at least 90%, such as at least 95%. The material can or can not be completely saturated with the additive (100% of the additive incorporated into the interstices). The process can involve the use of any one or more of: pouring; soaking; agitation; vibration; use of reduced pressure (such as by application of a vacuum); use of increased pressure. Such methods can utilize combinations of such techniques.

[0152] The use of reduced pressure can involve placing the material and additive in a fixed volume vacuum chamber or a variable volume vacuum chamber such as a bag, after which stage the pressure of the chamber is reduced, causing the gas in the material to expand and escape from the material being replaced by the additive. In one embodiment, the foam material is placed in a bag, the gaseous contents of the bag are removed by vacuum and the foam is compressed, then the additive is allowed to be introduced into the vacuum chamber, causing the foam to expand and / or be caused to expand to incorporate the additive. The additive can be introduced into the vacuum chamber in such a way that the vacuum in the chamber is reduced and the material expands, such as by using a peristaltic pump. This vacuum method can be particularly useful when incorporating molten wax into a foam, although in such embodiments it is typically necessary to ensure that the material is not fully saturated. In some embodiments, a material having a plurality of interstices, such as a network of voids, e.g. a foam, and a solid additive are placed in a vacuum bag; a vacuum is applied to the bag through one opening, which compresses the material and draws out all or some of the air; the outlet is subsequently sealed and the vacuum bag is heated, such as placed in a heated liquid, to melt the additive, causing the melted additive to be drawn into the material as it melts, resulting in a fully expanded material having the additive throughout when the contents of the bag return to atmospheric pressure. Some nominal advantages of this method include: simple equipment setup, requiring less space, and reduced spillage and hazardous exposure; improved repeatability and consistency by measuring the weight of additive required; and improved reliability with less need for heated conduits to prevent premature hardening and clogging.

[0153] In some embodiments, a shaped vacuum bag can be used as a mold, such that a material having interstices, e.g. voids, e.g. a foam, can be cooled and hardened without removal from the bag. The vacuum bag itself can be shaped or composed of one or more solid members having a shape, such as: two solid plates with a silicone corner brace or skirt connecting the two; or a plate with a vacuum sheet sealed around the perimeter. When a vacuum is applied, it provides a flat pressure on the material, and when the vacuum is released, it provides a flat surface for the material to cool against. In some cases, a bottom plate can be shaped as the intended work surface and placed on a machine bed to shape. Alternatively, one or more plates can be shaped, such as a mold. Nominal advantages are: simple equipment setup, requiring less space, and reduced spillage and hazardous exposure; material, e.g. foam, that is always flat and square when hardened; reduced warping if a two-plate setup is used on a thinner sheet, as it can be gently clamped / restrained from deforming; and / or potentially reduced process time and energy requirements if only smaller parts are needed or large sheets of material cannot be made.

[0154] In some embodiments, an additive can be used to expand a material having a plurality of interstices, such as a network of voids. For example: a material (e.g., a foam) can be contacted with an additive that causes the material to expand; the additive hardens, and thus the material is now in an expanded state; the material is shaped; and the additive is removed, and the material returns to its original size. The method provides a nominal advantage in that it can improve the permeability of an ultra-fine foam by increasing the overall size of the material and thus the flow of the additive into the material; and improve the processing resolution by expanding the size of the shape.

[0155] Another variation using reduced pressure is to apply a force to an elastic or viscoelastic material having a plurality of interstices, such as a network of voids, such that the material compresses and expels at least a portion of the contents in the voids from the material. Upon relaxation of the force, and in the presence of an additive, the material expands, thereby incorporating at least a portion of the additive into the material. For example, a foam can be submerged in a bath or pocket of liquid wax, the foam can be compressed to expel any incorporated gas, and then allowed to expand to incorporate some of the liquid wax from the bath. In some embodiments, it is desirable to saturate the material with the additive, while in other embodiments, it is desirable to only partially saturate the material with the additive. In this example, the amount of gas expelled can vary depending on the degree of compression of the material. The amount of gas present in the material can also be adjusted by a variety of techniques, including removing the partially compressed material from the bath before the material is fully expanded. Another technique includes only partially compressing the material such that the product material incorporates a portion of the additive and a portion of the gas. In another technique, the material is allowed to soak preferentially and non-uniformly from, for example, one aspect of the material, such that, for example, the material incorporates the additive to a greater degree on one face than other portions of the material. Such methods have been found to allow a user to produce a material incorporating a desired ratio of gas to wax. One or more similar methods can be applied to other materials and / or additives. It will be appreciated that the ability to compress an elastic or viscoelastic material having a plurality of interstices, such as a network of voids, represents a significant departure from existing methods for non-elastic or non-viscoelastic materials.

[0156] Advantageously, the methods of the present invention allow for adjustment of the amount of additive to be incorporated, as well as adjustment of the location of incorporation of the additive in the material. For example, the additive can be concentrated in a particular region to enhance the method and / or product. For example, an amount of wax can be incorporated into a foam sufficient to only coat the surface of the voids and immobilize a majority of the foam. As another example, an amount of wax can be incorporated in only the top layer of foam processed, thereby substantially hardening the material and providing a higher quality surface finish. Adjusting the amount of additive incorporated in the material allows for a reduction in the amount of additive required, thereby potentially facilitating easier removal of the additive.

[0157] While the process of contacting the material with additives has been described primarily with respect to foams and waxes, the use of non-liquid additives is also contemplated. For example, additives in granular, powdered form, or mixtures thereof, particularly those that are flowable, may be incorporated into the material by pouring or even using reduced pressure, particularly where the additive is airborne.

[0158] As used herein, the expression "subjecting the material to conditions such that at least a portion of the incorporated additive cures, hardens, and / or stiffens" refers to providing one or more external stimuli to change the conditions experienced by the material and additives. Examples of such stimuli include magnetic, electrical, thermal, chemical, mechanical, and electromagnetic.

[0159] Typically, the stimulus will be a thermal stimulus, such as one that causes the temperature of the additive to decrease. For example, the stimulus may simply be a decrease in the temperature of the environment in which the additive (and the material into which it is incorporated) is located, thereby lowering the temperature of the additive, causing the additive to solidify, harden, and / or become rigid, such as occurs when wax changes from a liquid state to a substantially solid state.

[0160] As described above, examples of other stimulation include: magnetic stimulation; application of force (including shear force) such as by application of high frequency mechanical waves; or application of electrical stimulation.

[0161] In some embodiments, it can be desirable to further manipulate the material prior to forming. Examples of manipulation can include: pressing, embossing, molding, folding, joining, splicing, and / or inserting pieces of material prior to hardening or introduction of the additive. Purposes can include pre-forming of shape (such as a mold), smoothing of multiple joined / spliced pieces of material, or pressing / compressing of material to reduce the amount of additive required. For example, pre-forming or compressing of the material with the additive can be used to simplify and speed up some operations. In such embodiments, for example, if replicating a shape, compression can typically occur with a male mold (and mirror image) - for example, to produce a foam hemisphere, the mold would be a convex hemisphere, and when pressed into the foam, the highest point of the hemisphere would be the lowest / compressed portion of the foam, and would emboss a concave impression in the foam. Thus, the process would include the steps of: contacting the foam with the additive, then placing it in a mold that compresses and embosses a hemisphere in the center; hardening the foam and additive in the mold; the embossed hemisphere is significantly lower than the rest of the foam, thus excluding it from the cutting operation; if in this case the foam is only face milled or planed to the depth of the embossing, the resulting foam will have a convex hemispherical shape that protrudes higher than the rest of the foam when the additive is removed. In another embodiment, the process includes the steps of: stamping a foam sheet with a liquid additive with a male mold; hardening the additive and leaving it compressed or embossed; cutting the material to remove the uncompressed portions; heating the additive and removing the additive to reveal a positive image replication of the mold. Such a process can be advantageous to quickly form a standard or general shape of an article prior to further forming, or to easily form a texture that might otherwise be time consuming to form. This can be used as a substitute for a foam winding machine, but the additive is able to maintain the shape until it is removed. It is believed that additional benefits are: more complex shapes can be formed; further processing of the compressed foam can be performed; not limited to roll pressing; the foam sheet can be kept compressed in shape or texture at room temperature for further forming; it allows for mass production of items using the original method. A possible further advantage of doing so is that the pre-compressed foam blank can contain, for example, an embossed standard wheelchair seat. Thus, a single cutting pass can provide a basic shape, followed by a calculated pass to customize the shape for a particular customer. This would effectively reduce the cutting depth required, increase speed, and reduce the volume of additive. Furthermore, the compressed foam is not permanently formed until the foam material is removed by machining. For example, a foam sheet with a crimped embossing can be heated, and then the foam is returned to a normal square foam sheet. If it is cut flat, a crimped sheet is produced. Knowing the shape and dimensions of the compression, the foam can still be shaped by compensating to make the foam beyond the embossed shape, so that selected crimp peaks can be removed by machining the compressed portions; or crimp troughs can be removed by not machining the uncompressed portions. Overall, these processes allow the core method of the present invention to expand from custom manufacturing to larger volume production, while adding flexibility and customization.In such embodiments, the compression process can be accomplished by, for example: compression prior to cooling; partially saturating and cooling the foam and then pressing and bonding the compressed pores; using a cold press to rapidly harden the partial foam. Alternatively, this can be accomplished using variants of the above additives (powder, wax, dry powder additives, etc.) with respective advantages. It can be seen that these processes can be combined with the core method of the present invention by using compression / pressing on one side and performing more complex machining on the opposite side.

[0162] Prior to and / or during shaping the material, the material is typically held firmly in place so that the shaping apparatus, for example, is movable and moves around the fixed material. Advantageously, certain embodiments of the present invention allow the material to be held firmly on a surface in such a way that the material can also be relatively easily removed from the surface when the shaping process is complete. In particular, a heated / cooled working surface can be used, such as provided by circulating heat transfer. In the case of additives such as wax that solidify, harden and / or stiffen as they are subjected to a temperature reduction, a foam incorporating such an additive can be placed on a surface at a given elevated temperature (typically above the melting temperature of the wax) and fixed to the surface by reducing the surface temperature below, for example, the melting temperature of the wax. It has been found that the material subjected to these conditions remains sufficiently fixed to the surface to allow the shaping process to take place. When the shaping process is complete, the temperature of the surface can be increased, the material will loosen and can be removed and / or repositioned. Such techniques offer significant advantages over previously disclosed processes that require the use of clamps, strong adhesives (such as superglue) that are believed to damage the material and are limited in the possible machining geometries.

[0163] As used herein, the expression "shaping the material" refers to any process that modifies the material from one shape to a different shape. Typically, the present invention is most suitable for subtractive shaping processes, which include hand shaping and machining. Examples of machining processes include computer numerical control (CNC) machining, such as contour machining. Such machining includes the use of lathes, mills, miller-lathes, multi-axis robotic arms, multi-axis water jets, lasers, hot wires, sonic knives, reciprocating blades / saws, knives, ablative tools.

[0164] Preferably, the machining process will use CNC machining, examples of subtractive machining, with a definable tool depth or tip. Such processes with a definable tool depth or tip typically include a spindle (mills and miller-lathes) or a combination of a spindle and a fed non-rotating tool (lathes and miller-lathes), ultrasonic tools (non-rotating cutters), reciprocating tools (reciprocating and concentric cutters), concentric rotating tools, abrasive / sanding / filing / furring knives.

[0165] Such processes with definable tool depth or tip generally do not include processes such as laser, water jet, plasma cutter, and air jet, and band saws, chain saws, and wire cutters that do not cut on a point or radius of a guide.

[0166] As used herein, the expression "removing at least a portion of" an incorporated additive refers to processes in which:

[0167] • agitating (e.g., shaking, vibrating, compressing (which can be slow or fast; and which can be repeated any number of times in compression / expansion cycles), or using centrifugal force) the material incorporating the additive, such that at least a portion of the additive is broken up and becomes unincorporated, and at which stage the unincorporated additive can be separated;

[0168] • placing the material incorporating the additive in a liquid bath, and then optionally agitating (e.g., shaking, vibrating, compressing, or using centrifugal force). The liquid bath can be at a different temperature (e.g., warmer) than the material before it is placed in the bath. The liquid can be a liquid that is immiscible with the additive. In one embodiment, the additive (e.g., a wax) melts and becomes unincorporated and separated from the material. For example:

[0169] o The material incorporating the wax can be placed in a warm water bath and agitated, such that the wax melts, separates from the material, and separates from the warm water, accumulating on the surface of the warm water.

[0170] o The material incorporating the wax can also incorporate a surfactant that optionally mixes with the wax. Upon being placed in a (optionally warm) water bath and agitated, the wax melts and the surfactant solvates, forming an emulsion of the wax and surfactant;

[0171] o The material incorporating the wax can be placed in a (optionally warm) water bath incorporating a surfactant, and the material can be agitated such that the wax (optionally melts), separates from the material, and emulsifies in the water;

[0172] o The material incorporating the wax can be placed in a (optionally warm) solvent bath (that is capable of solvating the wax), and the material can be agitated such that the wax (optionally melts) separates from the material and dissolves in the solvent.

[0173] • agitating (e.g., shaking, vibrating, compressing (which can be slow or fast; and which can be repeated any number of times in compression / expansion cycles), or using centrifugal force) the material while the material is heated, such that at least a portion of the incorporated additive melts and is expelled from the material. For example:

[0174] o In one such embodiment, the process can be performed by applying heat to the material incorporating the additive such that at least a portion of the additive melts before the material is compressed to expel a majority of the additive from the material;

[0175] o In another such embodiment, heat and compression can be applied continuously until a desired level of additive is removed;

[0176] o In another such embodiment, the material can be placed in a bag, the contents of which are subjected to reduced pressure by vacuum before the bag is subjected to heat to melt the additive, and then the additive can be removed from the bag under vacuum.

[0177] It will be appreciated that any of the above methods can be used to achieve partial or complete removal of the additive from the material. Typically, such methods will achieve partial removal of the additive from the material. In such embodiments, it can be desirable to use a secondary removal process to remove residual additive. Such secondary processes include any one or more of the above removal techniques. For example:

[0178] • applying a solvent to the material incorporating residual additive, optionally in combination with agitation (e.g. shaking, vibrating, compressing, or using centrifugal force).

[0179] The step of removing at least a portion of the incorporated additive can be prior to further steps of recovering surfactant, wax and water for reuse.

[0180] In a twelfth and thirteenth aspect, the present application provides a method of forming a shaped elastic or visco-elastic material having a plurality of gaps, such as a network of voids, the method comprising the steps of:

[0181] i. contacting an additive with a resin capable of curing to form an elastic or visco-elastic material in a vessel to form a mixture;

[0182] ii. degassing the mixture, such as by vacuum, and / or mixing the mixture to form a homogenous blend;

[0183] iii. curing the resin to form an elastic or visco-elastic material incorporating at least some of the additive;

[0184] iv. shaping the material incorporating the additive to form a shaped material incorporating the additive; and

[0185] v. optionally removing at least a portion of the incorporated additive from the shaped material incorporating the additive,

[0186] wherein the additive is not water, and the additive cures, hardens and / or stiffens when subjected to a change in conditions selected from heat, magnetism, electricity, chemistry and / or electromagnetism.

[0187] This aspect differs from other aspects in certain respects in that the elastomeric or viscoelastic material is formed from a resin that has been contacted with an additive. However, it shares several similarities. In particular, the formed elastomeric or viscoelastic material formed by this method can potentially be indistinguishable from the formed elastomeric or viscoelastic material formed by other methods disclosed herein. The resin method can provide certain advantages / disadvantages compared to methods of contacting an additive with an elastomeric or viscoelastic material.

[0188] The resin can be shrinkable (by heat, electromagnetic radiation, electricity, etc.), so the foam is formed in a larger size and shrinks. Nominal advantages of this method include allowing the formation of microstructures that would otherwise be too small to process; and / or improving the precision of the machine equipment - for example, forming in twice the size will effectively double the processing tolerance when the material is eventually shrunk. This resin technology can be applied to: developing implants; soft robotics; reproduction of very small biological structures. In the case of soft robotics, the resin can be reversibly controllable, providing a new type of multicellular pump or muscle analogue. This technology can also be combined with 3D printing, whereby: the additive is 3D printed to form the required gaps (such as a network of voids) and coated with the resin; and the additive and resin are 3D printed. It can be seen that this tenth aspect is fundamentally different from 3D printing of the shrinkable resin itself, as this method does not involve the use of an additive as defined herein and subsequent processing steps.

[0189] In some embodiments, the additive can be aerated prior to bead formation, have a sufficiently low vapour pressure, or contain a mixture that can expel gas. In such cases, the process can comprise the following steps: mixing the additive (such as beads) with the resin; curing the resin; placing the cured resin containing the additive with a sealed skin around its exterior in a vacuum chamber to produce the cured resin with the additive in the form of a foam, the foam incorporating the additive as a space holder; increasing the temperature of the vacuum chamber so that the additive melts and the pressure is reduced (in this case, in the case of an aerated additive, the trapped air expands, thus expanding the pores in the foam); cooling and hardening the additive to maintain the expanded state of the foam at normal atmospheric pressure; shaping the expanded foam to break the sealed skin; heating the material so that the additive can be removed and the foam returns to its original size.

[0190] Many of the above processes for removing the additive advantageously avoid the use of harmful solvents (compared to previously disclosed methods), thereby reducing the hazards, storage, and costs associated with solvents in previously disclosed methods.

[0191] Where the use of solvents can be avoided, the present invention increases the variety of materials suitable for the method, as the additive and removal method do not damage the material, whereas the solvent compatibility of all materials (especially foams) is not uniform.

[0192] Another advantage is ease of emulsification, particularly when the additive is incorporated into a mixture with a surfactant, then the use of agitation combined with the close proximity of the surfactant to the additive eliminates the problem of solvent penetration that can be found if trying to remove deeply embedded additives in larger items.

[0193] The present invention provides many advantages over previously disclosed methods. The previously disclosed methods do not address the environmental impact of their methods or disclose any advanced solutions. In contrast, the present invention allows for the recycling of the additive, thereby providing an advanced environmental and sustainable method. For example, the additive is easily extracted and recycled, allowing for the reuse of the additive, materials, and solvents (including water) in a closed loop system. It has been found that the use of additives derived from sustainable renewable resources can provide an improvement in environmental and sustainability impact. Another advantage is that the present invention can be adapted in such a way by contracting one or more process steps to a third party to improve the availability, quality, time, and cost associated with storage and equipment. One such way can be to license a third party to perform the step of incorporating the additive into the material to reduce cost, improve quality, and improve consistency. The prepared material can be delivered to parties intended to perform material shaping and additive removal as needed. The third party can then collect the additive and prepare new material and effectively recycle the foam waste. If necessary, the third party can further process the additive or reformulate it if needed. This will allow smaller entities to employ the method and dedicate the processing of the additive to larger entities or to an emerging group dedicated to additive processing and formulation and any waste processing.

[0194] Another method of reducing material waste facilitated by the present invention can be the preparation of shaped foam blanks for processing, such as foam seat orthotic blanks that can be processed according to specific needs, rather than processing large amounts of foam from square foam blocks to achieve the same shape as the orthotic blank.

[0195] Another advantage of the present invention is the control of particulate material (such as dust) during processing, which eliminates the need for extraction equipment as the additive is combined with the waste during processing, effectively encapsulating the particulate material, thus largely eliminating particulate in the air.

[0196] One advantage compared to other methods of producing shaped materials, such as foam articles, is the reduction in storage space required to store the molds, which require large storage areas or retooling of the molds from CAD files.

[0197] Another advantage is the ability to prepare materials with incorporated additives and store the prepared materials for extended periods without requiring specialized storage conditions (such as refrigeration required by some previously disclosed methods). In this manner, the prepared materials (e.g., foams) can be stored in large sheets or in predetermined sizes and shapes. Components can be removed from the sheets only when needed, which increases cutting efficiency and reduces waste. Furthermore, by enabling third parties to prepare the materials and provide them to entities that intend to shape them, the required equipment and space costs can be further reduced.

[0198] The present invention can also utilize 3D modeling. In a different approach than traditional mold manufacturing methods, minimal or non-contact 3D measurement, mapping, and / or tracking can be used to generate data that can be manipulated using CAD / CAM methods and subsequently output in a processed form. 3D measurement, mapping, and tracking can include typical medical imaging techniques such as MRI, CT, X-ray, or ultrasound, or 3D scanning, motion tracking and mapping techniques, or pressure mapping and imprint mapping.

[0199] Example

[0200] The following examples of the present invention are not exhaustive and are provided for illustrative purposes only.

[0201] An open-cell flexible foam block (2), which is an example of an elastic or visco-elastic material having a network of voids, is provided to be shaped by machining. In one embodiment, the block (2) can be saturated in a mold (4) to fully incorporate additives. The mold can have an open bottom (10) to allow the block to be secured to a machine bed, or the mold can have a closed bottom (12) to allow the block to be moved after incorporating additives, detached from the machine bed. In either case, the block can optionally be subjected to partial addition / removal of any additives (16) using a plunger. The mold can then be removed from the molded product, or secured to a machining bed (20), or detached from the machining bed (22). In the case of the material (22) incorporating additives being detached from the machining bed, it can subsequently be secured to the machining bed by a separate heating step to re-melt some of the wax (26) and secure it to the machining bed. In another embodiment, the block (2) can be contacted with hot melt wax in a bath (6), for example at 50-80°C, and optionally agitated by compression (14) using a plunger. The foam material can then be removed from the bath, and excess additives drained where needed to allow partial saturation (18). An optional secondary saturation step of a facet of the foam material (24) can be provided. In either case, the foam material can be secured to the machining surface by a separate heating step to re-melt some of the wax (26) and secure it to the machining bed. In another embodiment, the block (2) can be placed in a bag (8), which is subjected to a vacuum to reduce air in the foam before hot wax is pumped in to fill the air space and uniformly saturate the foam. After the foam material is removed from the bag, it can be secured to the machining surface by a separate heating step to re-melt some of the wax (26) and secure it to the machining bed.

[0202] The secured material (28) can then be processed using a range of processes. In one embodiment, the material can be processed by single-sided machining (30), the product of which can be removed from the machining bed by applying heat (34). In another embodiment, the material can be processed by two-sided machining (32), which produces a channel by leaving a border. The channel (36) can be filled with wax or even a wax / scrap (44) slurry before the top surface is machined flat. The piece (38) can then be subjected to heat to remove the piece from the bed (40) before being flipped and reannealed (42) to the machining surface. The flipped piece can then be machined (46) into a double-sided machined product (48) and removed from the machining bed (50).

[0203] In any embodiment, the material can be placed in a hot bath of wax (52) to re-melt the additive. Removal and application of agitation (compression) (54) can be performed to remove most of the wax. Alternatively, the material can be placed in a bag to which vacuum and heat are applied to remove the melted wax from the foam material. The finished piece (58) can be washed or left with wax residue to impart some water repellency, conditioning, and / or antimicrobial properties. Washing can be performed using a warm detergent (surfactant) solution in a bath; an ultrasonic bath using detergent and heat; continuous warm water flow or use of detergent; a warm detergent bath with agitator or compression. Alternatively, solvents can be used to recover residual wax by any of the above related methods.

[0204] Figure 4 The method of the present invention is shown to be applied to a plurality of shaped stock (60) as shown in Step 1A. Or to a shaped stock (62) to custom or machine to tolerance; or to rework previously shaped material as shown in Step IB.

[0205] Figure 5 An embodiment of the method of the present invention is shown. In particular, Step 1C illustrates an alternative process in which solid additives (64) are used to form voids in the resulting material as the additive is removed. Step 1 includes placing solid additives (64) in a container (66). Step 2 includes adding bulk elastomeric / viscoelastic material (68). Step 3 includes degassing or mixing the additives and bulk material as described above as needed and either remaining in the original container or transferring to one or more other containers, then curing, hardening, solidifying the bulk material. Step 4 includes shaping of the cured bulk material / additive mixture. Step 5 includes completing the shaping or further shaping operations to obtain the desired shape. Step 6 includes heating of the additives (70), which can be performed in a variety of ways with or without vacuum bagging. Step 7 includes removal of the additives by vacuum (72) and / or by compression (74) methods. Step 8 provides the finished piece. Further cleaning or processing can be performed if desired.

[0206] As a particular embodiment of the method, molten paraffin wax is dropped into a cold water bath at a constant rate to rapidly cool and form roughly spherical shaped beads. The paraffin wax is dropped from a height sufficient to form individual droplets but not so high as to produce irregular shaped pieces, such as flat splat shapes. The bath with constant circulating flow transports the paraffin wax beads away from the release point to minimize the fusion and aggregation of the beads. The paraffin wax beads are removed from the bath and dried. The beads are placed in a rectangular container and a two component addition cure silicone resin is prepared and added to the container. The container with uncured silicone and beads is placed in a vacuum chamber and subjected to reduced pressure to remove unwanted trapped air pockets. The container is removed from the vacuum chamber and the silicone is allowed to cure. Once cured, the silicone with paraffin wax beads can be removed from the container forming a rectangular block of silicone with paraffin wax beads incorporated. The rectangular block is secured to the table of a CNC router and machined to the desired shape. The machining process breaks the skin of the silicone which allows the paraffin wax additive to be removed. The shaped piece is heated to melt and the paraffin wax is removed by adding compression. A detergent wash can be used to remove unwanted residue. The final product is a shaped open cell elastomeric silicone foam.

[0207] In some embodiments, the additive beads can be selected from a range of suitable materials including: waxes, wax-like polymers, salts, sugars, sugar alcohols, and the like. The silicone "resin" can be replaced from a range of polymers characterized by properties such as: elasticity / viscoelasticity, resilience, softness, flexibility, and the like. "Curing" in a descriptive sense can describe a range of known methods depending on the substrate, such as: drying, cross-linking by electromagnetic radiation, heating, or synthesis.

[0208] Additionally, the additive can have secondary properties or be manipulated in a way that changes the final product. For example, prior to producing the shaped beads, the additive can be whipped to incorporate air into the mixture such that the solid shaped beads will contain a portion of air. The process of curing the silicone around the beads is then performed and then one or more paraffin wax beads are melted by heating the cured silicone. The heated silicone is then placed in a vacuum chamber. A vacuum is applied and the air bubbles dispersed throughout the additive expand. The skin formed around the outside of the silicone prevents the air from escaping the block of silicone material causing it to swell in size. The silicone piece is then cooled in the expanded state to maintain its shape. The piece is then machined and heated again and the additive removed returning the silicone piece to its original size. This process preferably includes the following events:

[0209] • The additive is formulated or melted in such a way that the air bubbles do not coalesce and prevent the retention of the expanded state;

[0210] • The silicone swells uniformly or predictably and does not break the skin;

[0211] • The strength of the additive when expanded is sufficient to maintain the expanded state of the silicone for processing.

[0212] Figure 6 Various embodiments of the method of the present application are shown, including the step of contacting the foam with an additive:

[0213] Step 2A includes a number of sub-steps:

[0214] • Sub-step 1 includes placing the foam (76) from Step 1A or 1B into a vacuum bag (78); Figure 4

[0215] • Sub-step 2 includes removing some or all of the air to compress the foam;

[0216] • Sub-step 3 includes introducing the additive (80) to contact the foam. This can be by negative pressure expansion of the foam or by injection through a pump, syringe, or other suitable means;

[0217] • Sub-step 4 provides the resulting foam with the additive.

[0218] Step 2B includes a number of sub-steps:

[0219] • Sub-step 1 includes the foam (82) in a container containing the additive (84; as an example, the additive is heated to a liquid state) and a suitable press (86);

[0220] • Sub-step 2 includes compressing the foam to expel all or some of the air therefrom;

[0221] • Sub-step 3 includes releasing the press to allow the additive to be drawn into the pores.

[0222] Step 2C includes a number of sub-steps:

[0223] • Sub-step 1 includes placing the foam (88) into a suitable vacuum bag (90) or similar container, with the additive (92) in a solid state;

[0224] • Sub-step 2 includes applying a vacuum to remove air and compress the foam, resulting in a solid additive and compressed foam;

[0225] • Sub-step 3 includes heating the additive and foam by suitable means, while still without air or partially without air;

[0226] • Sub-step 4 includes drawing the additive (as it becomes a liquid) into the compressed foam, resulting in uncompressed foam with the additive incorporated.

[0227] Figure 7 A process similar to that shown in Step 2B is shown, where the container acts as a mold: ​

[0228] Step 2D includes a number of sub-steps:

[0229] • Sub-step 1 includes placing the foam (94) in a container (96) containing the additive (98; as an example, the additive is heated to a liquid state) and a suitable press (100);

[0230] • Sub-step 2 includes compressing the foam to expel all or part of the air therein;

[0231] • Sub-step 3 includes releasing the press to allow the additive to be drawn into the pores and then cooling the foam / additive within the container;

[0232] • Sub-step 4A shows that the container or base of the container is the intended worktable or bed to be attached to a machine tool. The sides (102) of the container can optionally be removed.

[0233] • Sub-step 4B includes removing the hardened foam (104) from the container.

[0234] Figure 8 A process is shown in which solid particles, powder, etc. are the additive and are optional, or if desired, can be manipulated by external stimuli— solid or otherwise.

[0235] Step 2E includes a number of sub-steps:

[0236] • Sub-step 1 includes applying the additive (106) as solid particles to the foam (108) located in a container, agitating the container to facilitate movement of the additive into the foam.

[0237] • Sub-step 2 shows the additive in the foam

[0238] • Sub-step 3A includes shaping the foam and additive within the container into a substantially more rigid composite material.

[0239] • Sub-step 3B shows the additive undergoing a magneto-rheological change such that the individual particles are held substantially more rigidly or restricted from movement by a magnetic field applied in the vicinity of the container.

[0240] • Sub-step 3C shows the additive undergoing a magneto-rheological change such that the individual particles are held substantially more rigidly or restricted from movement by a magnetic field on the worktable or machine tool.

[0241] • Sub-step 4 shows the shaped foam being agitated to remove the additive, which can be further enhanced by the application of a magnetic field to assist in extraction and collection of the additive, while additionally separating waste from the additive. This can be in a bath or other place that is dry.

[0242] Figure 9It is shown how the addition or removal of heat can be used to change the properties of the additive.

[0243] Step 3A includes multiple sub-steps:

[0244] • Sub-step 1 includes concentrating the additive (110) in the desired foam area by: directing the cooling of the additive and foam (112); cooling with substantially more additive in the area of interest; or by reapplying to the desired area of the hardened foam

[0245] • Sub-step 2 (in the case of reduced additive requirements) can concentrate the additive in the area to be processed to improve the forming

[0246] In Step 3B, excess additive (114) can flow out or be compressed to the desired amount

[0247] In Step 4A, the foam can be allowed to harden and be fixed to the work surface.

[0248] In Step 4B, the foam can be hardened in a vacuum bag or other suitable container (including those of Step 3A) which can be shaped to a mold.

[0249] In Step 4C, the foam can be hardened by other means before being fixed to the work surface

[0250] Step 5 includes the following sub-steps:

[0251] • Sub-step 1 includes fixing the hardened foam to the work surface by heating the work surface or applying molten additive to the work surface (with or without a heated surface to adhere the foam).

[0252] • Sub-step 2 includes cooling the work surface to fix the foam or remaining cool without additional cooling. Alternatively, the foam can be fixed by any other means, such as standard workpiece fixtures, such as chucks, vices, clamps, vacuum clamps.

[0253] Figure 10 It is shown, as an example, how the process can be continued Figure 9 .

[0254] Step 6A(1) includes shaping the foam (116).

[0255] Step 6B illustrates a method for processing multiple sides, including the following sub-steps:

[0256] • Sub-step 1 includes applying the additive (118) to the multiple surfaces or to the shaped channel created prior to hardening.

[0257] • Sub-step 2 includes facing the top, either flat or shaped (such as for other mounting methods, such as nailing, vices, or interlocking members).

[0258] • Sub-step 3 (in the case of foam fixed by additives) heating the bed and repositioning the workpiece (120).

[0259] • Sub-step 4 (in the case of fixation by additives) positioning the workpiece and cooling the workbench.

[0260] • Sub-step 5 includes shaping the repositioned workpiece

[0261] • Sub-step 7 includes removing the shaped foam from the work surface by applying heat.

[0262] Figure 11 Removal of additives is illustrated.

[0263] Step 8A includes the following sub-steps:

[0264] • Sub-step 1 includes heating the shaped foam (122) by any suitable means, for example by conduction in a container of water or liquid additives or by radiating heat

[0265] • Sub-steps 2, 3, 4 show the heated shaped foam being pressed by suitable means.

[0266] Step 8B includes the following sub-steps:

[0267] • Sub-step 1 shows the shaped foam (124) in a suitable vacuum bag or arrangement as described in the preamble. The shaped foam is heated by suitable means as described in Step 8A. Vacuum can be applied before and during heating to improve the step.

[0268] • Sub-steps 2, 3 show the application of vacuum to remove additives, and then release of the vacuum to allow the foam to expand. Optionally, the bag can be compressed by some other means.

[0269] Further washing or removal of residue steps can be required.

[0270] Figure 12 And 13 It is shown how the addition or removal of heat can be used to change the properties of the additives.

[0271] Step 2F includes a number of sub-steps:

[0272] • Sub-step 1 includes placing the foam (126) in a container (128) containing additives (130; as an example, the additives are heated to a liquid state) and a suitable press (132);

[0273] • Sub-step 2 involves compressing the foam to expel all or part of the air therefrom;

[0274] • Sub-step 3 involves releasing the press to allow the additive to be drawn into the hole;

[0275] • Sub-step 4 involves compressing the foam with the mould (134);

[0276] • Sub-step 5 involves cooling the foam / additive whilst being compressed by the mould within the container;

[0277] • Sub-step 6 shows the hardened foam with the mould imprint;

[0278] • Sub-steps 7, 8 involve removing the foam material using a surfacing operation (profiling);

[0279] • Sub-step 9 involves heating the profiled foam by any suitable means, for example by conduction in a container of water or liquid additive or by radiated heat;

[0280] • Sub-step 10 involves compressing the heated foam / additive;

[0281] • Sub-step 11 shows the resulting foam in the shape of the mould.

[0282] Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".

[0283] The entire disclosure of all applications, patents and publications, cited above and below, if any, are hereby incorporated by reference.

[0284] No admission is made that any of the references constitute prior art. The references are provided solely for their disclosure prior to the filing date of the present application.

[0285] The application can also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, in any or all combinations of two or more of said parts, elements or features.

[0286] With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments only. Those skilled in the art will recognize the interchangeable use of the terms data and information.

[0287] It should be noted that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the application and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be included within the scope of the application.

Claims

1. A method of shaping an elastomeric or viscoelastic material having a plurality of interstices, the method comprising the steps of: i. providing the elastomeric or viscoelastic material having a plurality of interstices; ii. contacting the material with an additive such that at least a portion of the additive is incorporated into at least a portion of the plurality of interstices of the material; iii. subjecting the material to conditions such that at least a portion of the incorporated additive solidifies, hardens and / or stiffens; iv. shaping the material incorporating the solidified, hardened and / or stiffened additive, thereby forming a shaped material incorporating the additive; and v. removing at least a portion of the incorporated additive from the shaped material incorporating the additive, wherein the additive solidifies, hardens and / or stiffens at a temperature greater than 0 °C, wherein the elastomeric or viscoelastic material is shaped by a subtractive shaping process prior to removal of at least a portion of the additive from the elastomeric or viscoelastic material, wherein the subtractive shaping process comprises CNC machining. The plurality of interstices is a network of voids.

2. The method of claim 1, wherein, The elastomeric or viscoelastic material is selected from the group consisting of: a foam and / or sponge, a felt, a lattice, a scaffold, a roll good, a mesh and / or a net.

3. The method of claim 1, wherein, The elastomeric or viscoelastic material is a foam.

4. The method of claim 3, wherein, The additive is selected from the group consisting of: a wax or wax-like compound and mixtures thereof; a crystalline solid / supersaturated liquid; a liquid crystal compound; a solidified non-Newtonian compound; a granule / powder / other solid that can flow into the elastomeric or viscoelastic material; a liquid and / or solid that can be hardened or can be otherwise arranged and oriented to be stiffer.

5. The method of claim 1, wherein, The additive is a wax or wax-like compound.

6. The method of claim 1, wherein, The additive is a wax or wax-like compound selected from the group consisting of: an animal wax; a vegetable wax and hydrogenated vegetable oil; a mineral wax; a petroleum wax; a synthetic wax; and combinations thereof.

7. The method of claim 6, wherein, The additive is selected from the group consisting of: a polyolefin wax; a polyether; a chemically modified wax; and combinations thereof.

8. The method of claim 1, wherein, 9. A shaped elastomeric or viscoelastic material having a plurality of interstices prepared by the method of claim 1. ​

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