The present invention relates solid surface structures, and preferably to flat non-porous solid surface products comprised of: (1) a matrix made of polymethylmethacrylate, polyvinyl chloride, polycarbonate, or combinations thereof; and (2) one or more visible decorative objects that are permanently fixated in the matrix, and methods for manufacturing these products. These manufacturing methods do not involve using a mold or casting a liquid resin around the decorative object to be fixated. The solid surface products of the invention provide strikingly beautiful and unusual visual effects that are difficult to describe in words.
Solid surface products made of cured polymethylmethacrylate containing fine microscopic particles of inert inorganic fillers are known in the art. It is believed that all of the prior art polymethylmethacrylate solid surface products are made by using a mold and by casting therein a liquid acrylic resin which is then cured to form polymethylmethacrylate. For example, E. I. DuPont de Nemours and Company originated the solid surface category of products more than thirty years ago when it introduced the synthetic product sold under the trademark CORIAN which is believed to be a polymethylmethacrylate matrix containing large amounts of microscopic particles of inert inorganic fillers. It is believed that CORIAN is made by casting a liquid acrylic resin in a mold of some type and then curing the resin to form polymethylmethacrylate. CORIAN is usually an opaque product which mimics the decorative effect of marble. CORIAN is useful for kitchen countertops, kitchen sinks, bathroom lavatories, desktops, windowsills, and the like. Several patents owned by DuPont describe casting plastic simulated marble building products which are believed to be CORIAN. See Slocum U.S. Reissue Pat. No. Re 27,093, Duggins U.S. Pat. No. 3,488,246, Duggins et al. U.S. Pat. No. 3,642,975, Duggins U.S. Pat. No. 3,847,865, and Duggins et al. U.S. Pat. No. 4,107,135. In general terms, these DuPont patents describe cast products which are made of cured polymethylmethacrylate containing 30% to 80% by weight of microscopic particles (for example, particles having an average size of 7 microns) of inert inorganic fillers such as calcium carbonate, calcium sulfate, clay, silica, glass, calcium silicate, alumina, carbon black, titania, powdered metals, and alumina trihydrate.
Other synthetic solid surface products are sold by Avonite, Inc. under the trademark AVONITE which mimics the decorative effect of artificial stone. Risley U.S. Pat. No. 5,286,290 assigned to Avonite, Inc. describes dehydrating alumina trihydrate, rehydrating with a solution of dye, drying the solution to make colored alumina trihydrate, adding the colored alumina trihydrate to a resin matrix containing inert fillers, and cast to make a fire retardant solid decorative material having the appearance of artificial granite. The resin matrix may be ortho or iso polyesters, acrylics, or polycarbonates. The product may be in the form of a sheet or slab for kitchen countertops and decorative architectural surfaces or facades.
Eckart et al. U.S. Pat. No. 5,958,539 assigned to Eastman Chemical Company discloses a thermoplastic article having a fabric comprised of textile fibers embedded therein produced by applying heat and pressure to a laminate comprising, in order, (1) an upper sheet material, (2) a fabric comprised of textile fibers, and (3) a lower sheet material to produce a thermoplastic article having the fabric embedded therein. The upper and lower sheet materials are specifically made of PETG copolyester available from Eastman Chemical Company. PETG is the acronym for polyethylene terephthalate glycol.
A similar patent is Eckart et al. U.S. Pat. No. 5,998,028 assigned to Eastman Chemical Company which discloses a thermoplastic article having metallic wire, rod, and/or bar embedded therein produced by applying heat and pressure to a laminate comprising, in order, (1) an upper sheet material, (2) metallic wire, rods, or bars, and (3) a lower sheet material to produce a thermoplastic article having the metallic wire, rod, and/or bar embedded therein. As in Eckart et al. U.S. Pat. No. 5,958,539 above, the upper and lower sheet materials are specifically made of a PETG copolyester available from Eastman Chemical Company.
Another similar patent is Eckart et al. U.S. Pat. No. 6,025,069 assigned to Eastman Chemical Company which discloses a thermoplastic article having a high-relief, molded or embossed surface produced by contacting a laminate comprising a first or outer copolyester sheet material and a second or backing copolyester sheet material with heat and pressure using a heated element which simultaneously causes the material to be bonded and a high-relief, decorative appearance to be produced on at least one surface of the thermoplastic article. Also disclosed is an embossed or molded, bonded laminate comprising, in order, (1) a first or outer copolyester layer, (2) a second layer comprising a film which is colored or which bears an image or pattern, and (3) a third or backing copolyester layer, wherein the first and third layers are composed on the copolyester. As in Eckart et al. U.S. Pat. No. 5,958,539 and Eckart et al. U.S. Pat. No. 5,998,028 above, the copolyester layers are specifically made of a PETG copolyester available from Eastman Chemical Company.
Prior to the present invention, there existed a long-felt need for a dry process for making a solid surface product comprised of: (1) a matrix made of polymethylmethacrylate, polyvinyl chloride, polycarbonate, or combinations thereof; and (2) one or more visible decorative objects (objects that are visible to the unaided human eye) that are permanently fixated in the matrix. It was believed by knowledgeable people in the plastics industry that it was not possible to make such a solid surface product without using a mold and casting therein a liquid resin around the object to be fixated. It is believed that researchers who attempted to make such products using a dry process (that is, without using a mold and casting a liquid resin around the object to be fixated) produced products which contained defects such as air bubbles entrapped in the matrix, voids in the matrix, or cracks in the matrix.
Extensive research finally led to the present invention which allows an object to be fixated in a unitary matrix made of polymethylmethacrylate, polyvinyl chloride, polycarbonate, or combinations thereof, without using a mold and casting therein a liquid resin around the object. In addition, the present invention provides aesthetically-pleasing products which are free of defects of the type referred to above.
One example of the invention is a non-porous solid surface structure comprised of: (a) a flat non-porous unitary thermoplastic polymeric matrix made of polymethylmethacrylate, polyvinyl chloride, polycarbonate, or combinations thereof; and (b) a visible decorative object that is permanently fixated in the matrix, wherein the decorative object extends to least one edge of the matrix.
Other examples of the invention include a method for manufacturing non-porous solid surface structure including the steps of: (a) providing a first non-porous thermoplastic polymeric sheet made of polymethylmethacrylate, polyvinyl chloride, or polycarbonate; (b) placing a decorative object on the first sheet of polymeric material wherein the decorative object extends beyond at least one edge of the first sheet of polymeric material; (c) placing a second non-porous unitary thermoplastic polymeric sheet of made of polymethylmethacrylate, polyvinyl chloride, or polycarbonate on top of the decorative object wherein the decorative object also extends beyond at least the corresponding edge of the second sheet of polymeric material, whereby a lay-up sandwich is formed comprised of the first sheet of polymeric material, the decorative object which extends beyond at least one edge of both of the sheets of polymeric material, and the second sheet of polymeric material; (d) loading the lay-up sandwich into a press; (e) applying a predetermined amount of heat and pressure to the lay-up sandwich for a predetermined period of time; (f) opening the press to allow air and gases to escape from the lay-up sandwich; (g) closing the press and applying a predetermined amount of heat and pressure to the lay-up sandwich for a predetermined period of time whereby the first and second polymeric material sheets melt together in the lay-up sandwich to provide a unitary product; and, (h) allowing the product to cool while maintaining the pressure at a predetermined level until the product reaches a predetermined temperature at which point the press is opened and the product is removed from the press.
A preferred form of the invention provides non-porous unitary solid surface products and methods for manufacturing the same. By the term “unitary,” it is meant that the products are physically an undivided single piece, and therefore they are not a laminate structure consisting of separate layers that can be separated or delaminated. It should be understood that some products of the invention might visually appear (to the unaided human eye) to be a laminate of separate layers which maintain their integrity, but this visual appearance is not correct. The layers of polymeric starting material have in fact melted together and have become an undivided single piece. From the standpoint of aesthetically-pleasing visual appearance, line drawings and words are not capable of describing the strikingly beautiful and unusual visual effects provided by the solid surface products of the invention. The inventive solid surface products may be employed to make countertops, sinks, lavatories, desktops, table tops, chairs, windowsill, and the like.
The first embodiment of the invention, illustrated by the product in
The unitary solid surface structures 10 constructed according to the first embodiment of the present invention contain fixated decorative objects 14. The decorative objects 14 can be made of various materials as will be described below.
Variations on this basic lay-up sandwich may include more than two layers of polymeric material and multiple layers of decorative materials, alternating one and then the other. For example, the basic lay-up sandwich may consist of: (1) a top sheet of polymeric material; (2) a first layer of decorative material; (3) an intermediate sheet of polymeric material; (4) a second layer of a decorative material; and, (5) a bottom sheet of polymeric material.
The thickness of product 10 may range from about 0.030 inch (0.7937 mm) to 2.0 inches (50.80 mm). However, thicker and thinner gauges are possible based on the press capabilities and starting material availability.
The non-porous polymeric sheets 16 and 18 may be clear (transparent), colored, textured (on one or both faces), frosted, translucent, opaque, and they may also contain fire-retardant additives and performance additives.
The polymeric sheets 16 and 18 may vary in thickness from about 0.004 inch (0.100 mm) to 1.0 inch (25.4 mm). Also, the polymeric sheets 16 and 18 in the basic lay-up sandwich may vary in thickness from each other.
Polymethylmethacrylate sheet material can be manufactured by casting or by extrusion. The preferred polymethylmethacrylate sheet material is made by extrusion and has more consistent gauge. Polymethylmethacrylate sheet material made by casting has inconsistent gauge (hills and valleys) which will cause problems with air and gas entrapment and also gloss/texture problems on the surface of the product caused by pressure variations. In one embodiment of the invention, the decorative materials 14 are interleaved with the polymeric sheets 16 and 18 by co-extruding the polymeric sheets 16 and 18 on opposing sides of a suitably fed sheet of decorative material 14. In this process, the decorative material 14, typically any of fabric, paper or plastic film is roll laminated between the polymeric sheets 16 and 18. An embossing roller can optionally be used to control texture and gloss level of the sheet during extrusion.
The preferred polymethylmethacrylate sheet material has the following properties:
The preferred polyvinyl chloride sheet material has the following properties and is sold under the trademark INTEDUR TYPE II by World-Pak Corporation/Inteplast Corporation, Livingston, N.J.:
The preferred polycarbonate sheet material has the following properties and is sold under the trademark LEXAN 9600 by General Electric Company, Pittsfield, Mass.:
The material 14 to be fixated in the polymeric matrix 12 may be made of textile fabric, paper, plastic film, plastic sheet, metallic wire, rod, mesh, bar, wood veneer, and various dried natural materials (such as the long-stem grass illustrated in
The material 14 may be one or more layers of a textile fabric made of various fibers. Textile fabrics can impart beautiful and unusual visual effects to the product, such as an iridescent effect or a moiré effect. Non-limiting examples of suitable textile fabrics are: synthetic, semi-synthetic, naturally occurring and polymeric, including for example, rayon, polyester, nylon, synthetic polyamides (such as nylon 66 and nylon 6), acrylic, modacrylic, cellulose acetate, cotton, wool, silk and fiberglass. The fabric may be woven, knitted, spun-bonded, or prepared by other well-known processes in the textile trade. The fabric may be printed, coated, dyed, sublimated or decorated by other techniques known within the textile trade. Fabrics with loose weaves and have as open area of 0.005 inch or greater between yarns/threads are best. Fabrics with rough and porous surfaces are also preferred over smooth surfaces. Tightly woven fabrics with smooth surfaces will not function in the thermal melting process because they prevent resin transfer through the material. Natural fibers are preferred due to their porosity. The melted resin saturates such fibers more readily. The textile fabric may vary in thickness from about 0.00045 inch (0.0114 mm) to 0.25 inch (6.35 mm).
As mentioned above, the material 14 to be fixated in the matrix 12 may also be made of wood veneer, paper, dried plant fibers and parts. Non-limiting examples are: cellulose, cotton, linen, pulp, rag, dried plant materials and fibers including long-stem grass, leaves, petals, bark and twigs from reed, bamboo, papyrus, banana, mulberry, and wicker. For these types of material, the thickness of the layer may be from about 0.00045 inch (0.0114 mm) to 0.25 inch (6.35 mm).
The material 14 to be fixated in the polymeric matrix 12 may also be made of dry metal. Non-limiting examples are: copper, bronze, brass, steel, stainless steel, iron, nickel, and aluminum. Variety of shapes including: rod, mesh, sheet, perforated sheet, foil, strips, shavings, woven, and cable. The metal may be decorated such as etched, anodized, sanded, brushed, stained, painted, printed, chemically treated, galvanized, corroded, aged, polished, and plated. For these types of material, the thickness of the layer may be from about 0.00045 inch (0.0114 mm) to 1.0 inch (25.4 mm).
The material 14 to be fixated in the matrix 12 may also be a plastic sheet or film. Non-limiting examples are: polymethylmethacrylate, polycarbonate, polyvinyl chloride, PETG copolyester, polyethylene, polypropylene, polyester, polyvinylidinefluoride (PVDF) (sold under the trademark KYNAR), polyvinylfluoride (PVF) (sold under the trademark TEDLAR), and polyurethane. For these types of material, the thickness of the layer may be from about 0.00045 inch (0.0114 mm) to 1.0 inch (25.4 mm). Nor is it necessary that the decorative material 18 be a sheet. Plastic materials suitable for inclusion can be in any of cast, extruded, coated, calendared, or formed configurations. The plastic materials can include variations in qualities of the plastic such as different colors, finishes varying in texture, qualities of light transmission such as frosting, translucence, and opacity. Decorative qualities of the resulting lay up matrix 10a may optionally be enhanced by the eye-catching features included in the decorative materials 18. Such features may be distinctively colored, printed, metallized, sublimated, dyed, textured, painted, embossed, or foil stamped.
Decorative materials 14 may also include gems or glass products such as glass sheets, beads, or fragments. Where glass materials are used as the decorative material 14 the decorative material 14 may optionally include clear float glass, annealed or tempered glass. Surfaces of the glass may be suitably textured, tinted, frosted, etched, stained, colored, or sandblasted. Typically, thicknesses ranging from 0.090 inch (2.5 mm) to 1 inch (25.4 mm) are suitable for uniform heating across the polymeric sheets 16, 18, inasmuch as the glass introduces a significant variance in a specific heat of either of the polymeric sheets 16, 18. Furthermore, heating and cooling times may be adjusted to achieve suitable fusion of the polymeric sheets 16, 18.
The invention also includes a preferred method for manufacturing the solid surface structure 10. These manufacturing methods do not involve using a mold and casting a liquid resin around the object to be fixated.
In order to produce products 10 which are free of defects (such as air or gas bubbles entrapped in the matrix, voids in the matrix, or cracks in the matrix), to the preferred embodiment incorporates the following operating parameters. These process parameters work well with most paper and fabric decorative materials.
First, the basic lay-up sandwich must be processed in a heated press that can apply the required heat and pressure to melt the polymeric sheets 16 and 18 together and thereby create the matrix 12 that fixates the one or more decorative objects 14 within the matrix. Most preferred is a steam heated multiple opening press. Suitable presses include a multiple opening lamination press (MOP), autoclave, vacuum bag laminator, vacuforming machine, or other suitable machine that can apply the required heat and pressure to fuse the materials together
Second, when using the preferred polymeric sheets described above, the press should be preheated to a temperature of about 280° F. Then the lay-up sandwich is loaded into the press. The press is then closed against the lay-up sandwich at a pressure of about 40 pounds per square inch (psi). The press temperature is then ramped up until the lay-up sandwich reaches a temperature of about 290° F.-310° F. while maintaining the pressure at about 40 psi. This temperature works well for polymethylmethacrylate and polyvinyl chloride. Polycarbonate requires a higher temperature of about 350° F.-375° F.
Third, at this point the press is opened and all pressure is removed from the lay-up sandwich. This step is referred to as “bumping” the press. In some instances this step may be important in order to allow the heated air, water vapor, and gases to escape from between the polymeric sheets 16 and 18 in the lay-up sandwich so that bubbles or voids are not entrapped in the matrix 12. It should be understood, however, that this step is not essential to the invention.
Fourth, the press is then closed against the lay-up sandwich and the pressure is ramped up to about 160 psi. The press temperature is then ramped up until the materials in the lay-up sandwich reach about 290° F.-310° F. while maintaining the pressure at about 160 psi. Again, this temperature works well for polymethylmethacrylate and polyvinyl chloride, but polycarbonate requires a higher temperature of 350° F.-375° F. This pressure and temperature is then held for about 1 to 6 minutes depending on the thickness of the lay-up sandwich to allow the polymeric sheets 16 and 18 to melt together in the lay-up sandwich.
Fifth, the heat is turned off and the product is allowed to gradually cool while maintaining the pressure at about 160 psi until the product reaches a temperature of about 100° F. at which point the press is opened and the product (which needs some trimming) is removed from the press. If needed, a coolant may be circulated through the platens to cool the press. This step of gradually cooling the product is important because the product is being annealed, thereby removing the internal strains resulting from the previous operations. This prevents the polymeric matrix 12 from developing cracks, warping, or excessive shrinking. In the case of decorative objects 14 formed of glass and other highly heat-conductive materials, the head capacity and thermal conductivity of the decorative objects 14 and the polymeric sheets 16 and 18 may be very different. Accordingly, slower cooling times for such objects 14 may be used to avoid localized cold and hot areas which may cause internal stress and lead to the defects mentioned above.
Prior to full-scale production, the compatibility between specific decorative materials and the polymeric sheets should be evaluated. Some decorative materials can degrade under heat and pressure resulting in discoloration, color bleed, and separation.
During the pressing process, the outer surface of the polymeric sheets can optionally be deeply embossed or also textured using coated release papers or release films. A variety of suitable textured release papers made from polyester, polyvinyl fluoride and perfluoroalkoxy tetraflouroethylene are available from the S.D. Warren Company, Westbrook, Me. A variety of release films are available from the DuPont Company, Wilmington, Del. The release papers and release films have specific textures and gloss levels that are transferred onto the polymeric sheets during the pressing/heating operation. The release papers and release films also separate the polymeric sheets from the caul plate (described in Example 1 below) and thereby they prevent the polymeric sheets from sticking to the caul plate.
One of the advantages of the solid surface structures of the invention is that if they become scratched or marred, they are capable of being restored and refinished. This is particularly important for applications such as table tops and countertops. Refinishing may be accomplished for matte, semi-gloss, and high gloss finishes. The preferred process for refinishing uses an orbital disc sanding machine and film abrasives sold under the trademark TRIZACT and disc sanding pads sold under the trademark HOOKIT II, both products of Minnesota Mining and Manufacturing Co., St. Paul, Minn. The process involves sanding out the defects in the surface and then polishing.
During the pressing/heating operation, specialty films can also be applied one or both of the polymeric sheets to enhance the abrasion resistance, chemical resistance, and ultraviolet resistance of the final product. These specialty films may be made of various materials including polyester, polyvinylfluoride (PVF), ethylene trifluoroethylene (ETFE), fluorinated ethylenepropylene (FEP), polyvinylidenefluoride (PVDF), and chlorotrifluoroethylene (CTFE).
These specialty films can be on the top and/or bottom of the final product. Typically, these films have a higher melt point than polymethylmethacrylate and therefore require the use of a heat-activated adhesive coating, which is applied to the film prior to the pressing/heating operation. Generally, the specialty film has a thickness of 0.004 inch (0.100 mm) to 0.020 inch (0.500 mm).
In this example, the basic lay-up sandwich consists of three layers of the following starting materials: (1) a bottom sheet of the preferred polymethylmethacrylate material that is 0.060 inch thick, 48 inches wide, and 96 inches long; (2) a decorative textile fabric that is 58 inches wide and 102 inches long; and (3) a top sheet of the preferred polymethylmethacrylate that is 0.060 inch thick, 48 inches wide, and 96 inches long.
The final lay-up book is made as follows. A textured sheet of release paper that is 60 inches wide and 100 inches long is placed on a 0.060 inch thick aluminum caul plate and taped to the caul plate. The basic lay-up sandwich (described in the paragraph above) is placed on top of the textured sheet of release paper. The textured sheet of release paper will impart an aesthetically-pleasing texture to the outer surface of the bottom sheet of polymethylmethacrylate. The decorative textile fabric extending beyond the edges of polymethylmethacrylate sheets is pulled taunt and taped to the caul plate. Another sheet of textured release paper that is 60 inches wide and 100 inches long is placed on top of the basic lay-up sandwich. This textured sheet of release paper will impart an aesthetically-pleasing texture to the outer surface of the top sheet of polymethylmethacrylate. Another caul plate is placed on top of the upper sheet of textured release paper and the upper textured sheet of release paper is taped to the caul plate. Thermocouples are attached to the lay-up sandwich so that the temperature of the sandwich can be accurately measured.
Four plies of canvas are placed below the bottom caul plate and above the top caul plate to evenly distribute the pressure and heat during the pressing/heating operation. The book is placed on a 0.125 inch thick aluminum sheet loader pan to facilitate loading and unloading of the book into the press. In some embodiments, NOMEX felt or silicone sheets, rather than canvas, are used, such as 0.125 inch 45 durometer silicone sheets will also work with thermoplastic fusion but canvas padding has proven more economical. In some embodiments, textured or etched glass is used as the top and bottom layers of the laminate, in which case silicone plates may discourage breakage.
The press is preheated to a temperature of about 280° F. Then the final lay-up book is loaded into the press. The press is closed against the book at a pressure of about 40 psi. The press temperature is then ramped up until the lay-up sandwich reaches a temperature of about 290° F.-310° F. while maintaining the pressure at about 40 psi. The press is opened and all pressure is removed from the book. The press is closed against the book and the pressure is ramped up to about 160 psi. The press temperature is ramped up until the materials in the lay-up sandwich reach a temperature of about 290° F.-310° F. while maintaining the pressure at about 160 psi. This pressure and temperature is then held for about 1 to 6 minutes depending on the thickness of the lay-up sandwich to allow the polymethylmethacrylate sheets to melt together in the lay-up sandwich to provide a unitary product.
The heat is then turned off and the product is allowed to gradually cool while maintaining the pressure at about 160 psi until the product reaches a temperature of about 100° F. at which point the press is opened and the product (which may need some trimming) is removed from the press. Alternatively, the product may be removed from the press after heating and moved into a second press having a lower temperature than the first press. The second press may then continue to apply pressure, such as at 160 psi until the product is removed. The second press may be maintained at a lower temperature than the first press by means of chilling or simply by refraining from heating the second press. Use of a second, colder press may facilitate rapid manufacturing times inasmuch as heat transfer rates are increased.
Example 1 can also be performed using polyvinyl chloride or polycarbonate, but polycarbonate requires the higher temperature of 350° F.-375° F. Example 1 can also be performed using a combination of polymethylmethacrylate, polyvinyl chloride, or polycarbonate. There are benefits in combining the properties of two thermoplastics. For example, by combining polyvinyl chloride and polymethylmethacrylate, the polyvinyl chloride will improve the flammability and chemical resistance of the polymethylmethacrylate, and the polymethylmethacrylate will improve the clarity, ultraviolet resistance, and abrasion resistance of the polyvinyl chloride. The thermoplastics need to be formulated to have similar processing temperatures to work in the press process.
In this example, the thickness of the product is 0.25 inch or greater. When fabricating products in a thickness of 0.25 inch or greater employing delicate decorative papers, fabrics, or organic materials, a first stage is necessary to encapsulate the decorative material within two thin sheets of 0.060 inch polymethylmethacrylate to prevent tearing of the decorative material caused by movement of the polymethylmethacrylate during pressing. The thinner sheets of polymethylmethacrylate will hold the decorative material in place with minimal movement during stage two. The two-stage process enables products to be made in thicker gauges with less “melt out.” Thus, maximum thickness is preserved. The goal is to transfer heat to the lay-up sandwich to melt the polymethylmethacrylate sheets together using the least amount of heat, pressure, and time.
In stage 1, a 0.12 inch intermediate product with 0.005 inch relief texture is made encapsulating the delicate decorative material. First, an intermediate lay-up book is made consisting of the following sequence from top to bottom: (1) four plies of canvas padding; caul plate; (2) textured release paper or plate providing 0.005 inch relief; (3) 0.060 inch clear polymethylmethacrylate sheet (size 48 inches by 96 inches); (4) a layer of the delicate decorative material; (5) 0.060 inch clear polymethylmethacrylate sheet (size 48 inches by 96 inches); (6) textured release paper or plate providing 0.005 inch relief; (7) caul plate; and, (8) four plies of canvas padding.
The press is heated to about 280° F., the intermediate lay-up book is placed in the press, and the press is closed. The pressure is brought to 40 psi. When the materials in the lay-up reach 290° F., the pressure is increased to 160 psi and held for 1 minute. The intermediate product is then gradually cooled to 100° F.
In stage 2, the final lay-up book is made consisting of the following sequence from top to bottom: four plies of canvas padding; caul plate; textured release paper or plate; 0.060 inch clear polymethylmethacrylate sheet (size 48 inches by 96 inches); 0.12 inch textured intermediate product (from stage 1) encapsulating the delicate decorative material delicate decorative material; 0.060 inch clear polymethylmethacrylate sheet (size 48 inches by 96 inches); textured release paper or plate; caul plate; and, four plies of canvas padding.
The press is preheated to a temperature of about 280° F. Then the final lay-up book is loaded into the press. The press is closed against the book at a pressure of about 40 psi. The press temperature is then ramped up until the lay-up sandwich reaches a temperature of about 290° F.-310° F. while maintaining the pressure at about 40 psi. The press is opened and all pressure is removed from the book. The press is closed against the book and the pressure is ramped up to about 160 psi. The press temperature is ramped up until the materials in the lay-up sandwich reach a temperature of about 290° F.-310° F. while maintaining the pressure at about 160 psi. This pressure and temperature is then held for about 1 to 6 minutes depending on the thickness of the lay-up sandwich to allow the polymethylmethacrylate sheets to melt together in the lay-up sandwich to provide a unitary product.
The heat is then turned off and the product is allowed to gradually cool while maintaining the pressure at about 160 psi until the product reaches a temperature of about 100° F. at which point the press is opened and the product (which may need some trimming) is removed from the press. Alternatively, product removed from the press after heating and moved into a second press having a lower temperature than the first press. The second press may then continue to apply pressure, such as at 160 psi until the product is removed. The second press may be maintained at a lower temperature than the first press by means of chilling or simply by refraining from heating the second press. Use of a second, colder press may facilitate rapid manufacturing times inasmuch as heat transfer rates are increased.
Example 2 can also be performed using polyvinyl chloride and polycarbonate, but polycarbonate requires the higher temperature of about 350° F.-375° F. Example 2 can also be performed using a combination of polymethylmethacrylate, polyvinyl chloride, or polycarbonate.
This is an example of the second embodiment of the invention illustrated by
In stage 1, an intermediate lay-up book is made consisting of the following sequence from top to bottom: (1) four plies of canvas padding; caul plate; (2) textured release paper or plate providing 0.005 inch relief; (3) 0.060 inch clear or colored polymethylmethacrylate sheet (size 48 inches by 96 inches); (4) textured release paper or plate providing 0.005 inch relief; caul plate; and, (5) four plies of canvas padding.
The press is heated to about 280° F., the intermediate lay-up book is placed in the press, and the press is closed. The pressure is brought to 40 psi. When the lay-up reaches about 290° F., the pressure is increased to 160 psi and held for 1 minute. The intermediate product is then gradually cooled to 100° F.
In stage 2, the final lay-up book is made consisting of the following sequence from top to bottom: (1) four plies of canvas padding; (2) caul plate; (3) textured release paper or plate; (4) 0.060 inch clear polymethylmethacrylate sheet (size 48 inches by 96 inches); (5) 0.060 inch textured intermediate product (from stage 1); (6) 0.060 inch clear polymethylmethacrylate sheet (size 48 inches by 96 inches); (7) textured release paper or plate; (8) caul plate; and, (9) four plies of canvas padding.
The press is preheated to a temperature of about 280° F. Then the final lay-up book is loaded into the press. The press is closed against the book at a pressure of about 40 psi. The press temperature is then ramped up until the lay-up sandwich reaches a temperature of about 290° F.-310° F. while maintaining the pressure at about 40 psi. The press is opened and all pressure is removed from the book. The press is closed against the book and the pressure is ramped up to about 160 psi. The press temperature is ramped up until the materials in the lay-up sandwich reach a temperature of about 290° F.-310° F. while maintaining the pressure at about 160 psi. This pressure and temperature is then held for about 1 to 6 minutes depending on the thickness of the lay-up sandwich to allow the polymethylmethacrylate sheets to melt together in the lay-up sandwich to provide a unitary product.
The heat is then turned off and the product is allowed to gradually cool while maintaining the pressure at about 160 psi until the product reaches a temperature of about 100° F. at which point the press is opened and the product is removed from the press. The product has a stratum of the textured material permanently fixated in the matrix and co-extensive with the edges of the matrix. The flat product may be subjected to conventional thermoforming/shaping processes if a non-flat shape is desired.
This Example 3 can also be performed using polyvinyl chloride and polycarbonate, but polycarbonate requires the higher temperature of about 350° F.-375° F. Example 3 can also be performed using a combination of polymethylmethacrylate, polyvinyl chloride, or polycarbonate.
Referring to
The polymeric layers 16 and 18 may be curved prior to bonding to one another and the decorative materials 14. Alternatively, the press used to perform the above methods may be contoured such that the layers 16 and 18 are in the form of sheets that are bonded to one another and shaped simultaneously. In yet another embodiment, the product of the above methods may be subsequently processed into a contoured shape, such as by application of heat and pressure within a contoured press.
Referring specifically to
In other embodiments, the film 30 is an antimicrobial polymers preventing growth of bacteria, molds, and fungi. For example, MICROBAN™ polymer manufactured by the Microban Products Company™ may be used. An antimicrobial polymer may coat solid surface structures 10 forming children's chairs, changing tables, and countertops or any area where accumulation of microbes is a concern.
The film 30 may also provide chemical or ultraviolet resistance. Suitable materials for such films include polyester, Polyvinyl floride (PVF), Ethylene/trifluoro ethylene known as ETFE, fluorinated ethylene propylene known as FEP, polyvinylidene floride (PVDF), chlorotrifluoro ethylene (CTFE), or acrylic resin film such as polymethyl methacrylate, as well as various polymer extruded products.
Typically, such films have a higher melt point than the fusion point of thermoplastic used for the polymeric sheets 16, 18. Because the fusion temperature of such films is high enough to melt the thermoplastics allowing the thermoplastic to flow out of the pressure fixture, the fixation of the film 30 to the polymeric sheets 16, 18 requires interposing a heat activated adhesive coating to be applied to the film prior to bonding to most plastic substrates. Generally, the film's thickness ranges from 0.004 inch (0.100 mm) to 0.020 inch (0.500 mm).
The film 30 may also be abrasion resistant. Abrasion resistant materials include those having heat, ultraviolet or electron beam cured material deposited on a film of polyvinyl chloride PETG copolyester, polyethylene terephthalate, polymethyl methacrylate or polycarbonate. In addition, the abrasion resistance coating can be achieved with a heat cured silicone, polyurethane or fluorinated polyurethane or an ultraviolet or electron beam cured material selected from modified acrylates containing polyurethane, fluorinated polyurethane, silicone, epoxy, polyester, polyether or caprolactone residues.
The decorative object layer 14 of the laminate may also have operative properties. For example, the decorative object layer 14 may be embodied as a photoluminescent sheet 32 or distribution 32 of discrete pieces of photo-luminescent materials. In still other embodiments, the layer 14 may be embodied as a sheet 32 or distribution 32 of particles formed of ferromagnetic materials such that the solid surface structure 10 functions as a magnetic bulletin board in addition to a dry-erase board. The sheet 32 may also be formed of a fire retardant or resistant material. In other embodiments, the sheet 32 made of a honeycomb core, or perforated core material in order to reduce the weight of the solid surface structure 10.
The sheet 32 or distribution 32 may be textured or patterned, extend beyond the edges of the polymeric layers 16 and 18, or be otherwise adapted to facilitate release of gases as described above. For example, grooves or cut-outs in the sheet 32 may extend from proximate within the polymeric layers 16 and 18 to the edges thereof.
Referring to
Referring to
The first and second outer layers 36, 48 may be abrasion resistant or have an abrasion resistant coating. In the illustrated embodiment, ⅛ inch polycarbonate, acrylic, or glass is used. The adhesive layers 40, 44 may adhere the first and second outer layers 36, 48 and the decorative layers 38, 48 to the structural layer 42. In the illustrated embodiment the adhesive layer is a polyurethane adhesive, which may have a thickness of 25 to 50 thousandths of an inch. The structural layer 42 may be embodied as glass, polycarbonate, or acrylic. In the illustrated embodiment, ½ inch polycarbonate is used.
The layers of the bullet-resistant laminate may be assembled to form a lay-up sandwich which is processed according to the methods described above in order to fuse the layers. For bullet-resistant laminates formed of polycarbonate, acrylic, and polyurethane adhesives, the press may be heated to a temperature of from 185 to 257° F. and apply a pressure of from 50 psi to 200 psi.
Various embodiments for the layers forming the bullet-resistant laminate may be used. For example, a single decorative layer 38, 46 may be included. Furthermore, multiple structural layers 42 secured to the laminate by additional adhesive layers 40, 44 may be included. Additional decorative layers 38, 46 may likewise be included.
The layers of the bullet-resistant laminate may be assembled to form a lay-up sandwich which is processed according to the methods described above in order to fuse the layers. For bullet-resistant laminates formed of polycarbonate, acrylic, and polyurethane adhesives, the press may be heated to a temperature of from 185 to 257° F. and apply a pressure of from 50 psi to 200 psi. Various embodiments for the layers forming the bullet-resistant laminate may be used. For example, a single decorative layer 82, 90 may be included. Furthermore, multiple structural layers 42 secured to the laminate by additional adhesive layers 40, 44 may be included. Additional decorative layers 38, 48 may likewise be included. The bullet resistant properties of the laminate of
Referring to
Referring to
In some embodiments, the step of fusing the polymeric layers 16, 18 is performed simultaneously with the step of forming the layers 16, 18 into an alternative shape. In the embodiment of
Referring to
Various thermoplastic materials may be used for the polymeric sheets 16 and 18 in the various embodiments described hereinabove. For example, acrylic resins such as Polymethyl Methacrylate, known as PHMA, Polycarbonate, Polyvinyl Chloride, Polyethylene in either of high density polyethylene and low density polyethylene, Polypropylene, Polyester, Nylon and Polyurethane, Polystyrene, Fluoropolymers, Acrylonitrile-Butadiene-Styrene (ABS). Acrylic polymers may include combined cross linked and standard acrylic or 100 percent cross linked acrylic. Combination plastics, such as CPVC, ABS/Polycarbonate, ABS/PVC, Polycarbonate/Acrylic, or PVC/Acrylic. Biodegradable thermoplastics such as polylactic acid (PLA) and cellulosics such as ethyl cellulose, cellulose acetate, cellulose acetate butyrate, cellulose acetate propioniate, and cellulose nitrate serve may also be suitable.
While the preferred embodiments of the invention have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.
This application is a continuation-in-part of the application Ser. No. 10/762,206 filed on Jan. 21, 2004 and entitled, “Solid Surface Products,” the application being a divisional application of U.S. patent application Ser. No. 10/106,833, filed Mar. 25, 2002 and entitled, “Solid Surface Products,” which claims priority from U.S. Provisional Application No. 60/307,898 filed Jul. 25, 2001. Each of the Utility Patent applications and the Provisional Patent application is incorporated herein by reference.
Number | Date | Country | |
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60307898 | Jul 2001 | US |
Number | Date | Country | |
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Parent | 10106833 | Mar 2002 | US |
Child | 10762206 | Jan 2004 | US |
Number | Date | Country | |
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Parent | 10762206 | Jan 2004 | US |
Child | 11364920 | Mar 2006 | US |