The present invention relates to methods and systems for applying images to materials. More particularly, the present invention provides methods and systems for forming images on polymeric substrates and other resin materials during their curing processes.
Numerous processes ace currently utilized to apply images to substrates, such as by using masks, etching, photocopying, dye sublimation, dye diffusion thermal transfer, and ink jet, laser, and other printing techniques. The processes are less varied, however, when attempting to apply images to particle-filled resin materials, such as cultured marble. Such composite substrates have become very popular for a variety of home uses, in particular for kitchen and bathroom surfaces because of their strength, durability, resistance to staining, and ease in cleaning.
It has been difficult to apply images deeply and permanently in such polymeric materials. Consequently, image fading from wear or exposure to sunlight has been a major problem. Masking and etching have sometimes been used, but the processes have been expensive and time consuming.
For the most part, the industry has focused on applying images to substrates from a transfer medium having an image thereon in dyes capable of sublimation. In some cases, a substrate is formed and cured before applying the transfer medium. A gel coating may first be applied to a substrate, and the gel coat is also allowed to cure. Then the transfer medium having a image formed by sublimable ink is brought into contact with the substrate or coating, and heat and/or pressure are applied to cause the image to sublimate into the substrate or coating. Commonly, a heat press is used to apply substantial heat and pressure to facilitate the image transfer.
U.S. Pat. No. 7,001,660 (Garitano) discloses an image transfer method using a cured polymeric composite substrate. The substrate is brought into contact with an image transfer medium having an image formed by sublimable ink thereon, while applying heat and/or pressure, U.S. Pat. No. 7,108,890 (Home) discloses applying a polymeric coating to a porous natural or synthetic surface. After the coating has cured, an image of sublimation inks is transferred to the coating from a transfer medium, by sublimation facilitated by heat and pressure, U.S. Published Patent Application No. 2005/0227006 (Segall) discloses applying a gel coat to a substrate of composite material and then transferring an image to the coated composite by sublimation using heat and pressure.
Substrate 23 may be a natural product like stone, masonry, ceramics, marble, or concrete, or a synthetic product such as cultured marble or other polymeric composite material. If substrate 23 is a polymeric composite material, it is produced in a separate molding process (not shown). A liquid resin 26, such as a polyol resin, may be applied to the substrate 23 in any conventional method, such as by brush 28 or spray 30. The resulting coating 24, referred to as a receptor coating, is allowed to cure by drying, hardening, absorbing, or reacting with a catalyst.
Next, the transfer sheet 20 is applied to a surface of the receptor coating 24, and is subjected to heat and pressure by a heat press 22. The heat and pressure cause the ink to sublime into the receptor coating 24 over the sublimation period. The resulting coated substrate has an image 12 imprinted on the receptor coating 24.
The entire process may require several hours of time to cure the polymeric substrate and the coating thereon. In addition, time is required to heat and press the image on the coating and then to cool the substrate and coating. Furthermore, a large and expensive heat press must be used to apply substantial heat and pressure, typically around 300-500° F. and 20-60 psi. The process is also labor intensive, requiring a skilled craftsman to operate the hand press and another craftsman to mix and pour the polymeric substrate and the resin coating. Finally, unless the receptor coating 24 has incorporated therein a UV-resistant material, the resultant image will exhibit poor light-fastness.
These prior art processes tend to be expensive and time consuming. Substantial cure time is required for the composite substrate and the coating before applying the image. Typically a large and expensive heat press is used to apply heat and pressure for the image transfer. Even then, the manufactured article exhibits poor light-fastness, particularly under prolonged exposure to the ultraviolet rays of sunlight, unless a separate UV-protective coating is applied.
This light-fastness weakness is tied directly to the use of dye sublimation inks. As is well known by those familiar with the art of inkjet printing, dyes inherently exhibit poor light-fastness due to the fact that each dye molecule functions to provide color and is therefore exposed to UV radiation. However, dyes must be used for sublimable inks since the particulate property of pigments cannot be maintained during sublimation. Accordingly, this weakness makes dye sublimation inks particularly unsuitable for applications involving cultured marble and some other resin composites, since the areas of use for these materials often expose them to direct sunlight. Therefore, the use of dye sublimation inks requires the application of an additional material to provide UV resistance, which adds time and cost to the production process and reduces the flexibility of the application.
Moreover, the sublimation process is problematic due to the limitations of the dyes and dye colors and the necessity of special transfer materials having dye-acceptable coatings thereon, which add to the total cost of the process. In addition, since heat and pressure are required to drive the sublimation process, the necessity of using heat-resistant substrates has eliminated the use of some, otherwise-desirable materials. For example, the heat required for sublimation typically exceeds the heat distortion temperature limits of some composite materials, such as cultured marble.
In view of the foregoing, it will be appreciated that providing methods for transfer of an image to resin materials without the need for applying heat and/or pressure would be a significant advancement in the art.
in the present invention, a method of transferring images to a wide range of substrates is provided, in one illustrative embodiment, a transfer medium having an image thereon is placed image up in a mold for forming, polymeric composite substrates. A polyester resin with filler is poured into the mold over the transfer medium. As the polymeric substrate is cured, the image is transferred to the adjacent face of the substrate by chemical absorption. The imaged substrate is then removed from the mold and coated with a clear protective coating over the image.
In another illustrative embodiment, a thin layer of polyester resin is first poured into a mold for forming polymeric composite substrates to form a thin coating layer. A transfer medium having an image thereon is then placed image down in the mold over the coating. The image is transferred to the coating by chemical absorption as the coating cures. The transfer medium is removed from the protective coating to which the ink is now absorbed. A polyester resin with filler, pigment, and initiator is then poured into the mold over the imaged protective coating. The substrate with imaged protective coating is then removed from the mold.
In another illustrative embodiment, a transfer medium having an image on one side is placed in contact with a thin layer of liquid polymer resin. The image side of the transfer medium is brought in direct contact with an adjacent surface of the layer of polymer resin while it is curing, allowing the image to transfer to the polymer resin during the cure stage as the polymer resin becomes a solid resin layer. The transfer sheet is then removed from the substrate, leaving the image on the adjacent surface of the solid resin layer.
Before the present methods are disclosed and described, it is to be understood that this invention is not limited to the particular configurations, process steps, and materials disclosed herein as such configurations, process steps, and materials may vary somewhat. It is also to be understood that the terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting since the scope of the present invention will be limited only by the appended claims and equivalents thereof.
The publications and other reference materials referred to herein to describe the background of the invention and to provide additional detail regarding its practice are hereby incorporated by reference. The references discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the inventors are not entitled to antedate such disclosure by virtue of prior invention.
it must be noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a liquid resin” includes a mixture of two or more resins, reference to “an image” includes reference to one or more of such images, and reference to “an ink.” includes reference to a mixture of two or more inks.
Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which this invention belongs.
in describing and claiming the present invention, the following terminology will be used in accordance with the definitions set out below.
As used herein, “comprising,” “including,” “containing,” “characterized by,” and grammatical equivalents thereof are inclusive or open-ended terms that do not exclude additional, unrecited elements or method steps. “Comprising” is to be interpreted as including the more restrictive terms “consisting of” and “consisting essentially of.” As used herein, “consisting of” and grammatical equivalents thereof exclude any element, step, or ingredient not specified in the claim. As used herein, “consisting essentially of” and grammatical equivalents thereof limit the scope of a claim to the specified materials or steps and those that do not materially affect the basic and novel characteristic or characteristics of the claimed invention.
In contrast to the prior art process described in the Background, the embodiments of the present invention disclose a much faster, simpler, and less expensive process that is also capable of providing an image with much improved UV resistance. Images are transferred to substrates or coatings for substrates while the substrates or coatings are being formed and/or cured. The chemical absorption process that occurs while a substrate or coating is in a gel state and curing is sufficient to facilitate image transfer at room temperatures without the application of further heat or pressure.
The reasons that image transfer to resin gels works well at room temperatures are not fully understood. However, it is thought that an image on a transfer sheet transfers readily to polymer molecules in a viscous or gel state because the polymer molecules are more mobile than solid state molecules and chemical bonding can be more readily effected. This mobility provides a high degree of bonding between ink and polymer molecules that cannot be achieved with solid molecules in cured materials, unless sublimation ink designs are used, accompanied by substantial heat and pressure. This process is referred to herein as chemical absorption. Other theories that could come into play in this invention are the likelihood of diffusion and/or solvation. There could be some diffusion of an image into the resin gel occurring because of a relatively high solvent content of the gel. In addition, the solvent content of the resin gel may cause a dissolving or swelling of the ink-receptive coating on the transfer sheet, thus weakening the coating and facilitating image transfer to the gel coat layer. The foregoing theories are conjecture and have no effect on the scope of this patent application. As used herein, the term “liquid resin” refers to a resin in various stages of curing from a pure liquid to a gel form and may include filler and/or reinforcement.
Image transfer is accomplished without sublimation, opening up the use of less expensive inks also providing improved light-fastness (such as solvent- or aqueous-based pigment inkjet inks) for the images. Thus, images are transferred quickly and inexpensively to substrates and coatings at room temperature using relatively inexpensive materials and yielding a higher quality product. Images are transferred to resin layers that can be easily applied to any structure or surface.
Transferring Images to Substrate. Referring now to
The transfer sheet 60 is then laid face up in a mold 62. Various means, such as vacuum or taping, may be used to secure the transfer sheet 60. A liquid matrix 80 may be formed, for example, by combining a polyester resin 70, an inorganic filler 72, a pigment 74, and an initiator 76, which is then poured over the transfer sheet 60 in mold 62. The liquid matrix 80 cures through chemical cross-linking, and the pigmented ink of image 52 in transfer sheet 60 is absorbed during the cure of liquid matrix 80 onto an adjacent surface 82 of the now-solid matrix 80, apparently using a process of chemical absorption.
The cured or curing substrate is removed from the mold at any selected time, and the transfer sheet 60 is removed from surface 82. Further curing may be carried out, as needed. The imaged surface 82 is then covered with a top coat 84 to provide protection from scratching and wearing. Note that the top coat 84 does not need to provide UV resistance for pigmented inks, as would be the case if dye-based inks were used to form the image on transfer sheet 60.
Transferring Images to Substrate Coating. Looking next at
Next, a mold 112 is covered with a thin layer of liquid resin, which may be called a gel coat 114, by spraying, pouring or brushing resin 116 therein. At any desired point, while the coat 114 is still curing, the transfer sheet 110 is laid face down in mold 112 so that the image 102 is in contact with the curing gel coat 114. Again, the image 102 is transferred to the gel coat 114, apparently by a process of chemical absorption. The transfer sheet 110 is then removed from mold 112.
A liquid matrix 130 is formed by combining, for example, a polyester resin 120, an inorganic filler 122, a pigment 124, and an initiator 126. The liquid matrix 130 is then poured over the gel coat 114 in mold 112. The liquid matrix 130 solidifies through chemical cross-linking, and is integral with gel coat 114.
In contrast to the process 50 shown in
Transferring Images to Resin Layer. Looking now at
The film 202 is first partitioned in some manner, such as by using tape or strips of plastic. Film 202 is then covered with a thin layer of liquid resin 204 by pouring from a container 206, or by spraying, brushing or other means. At some point in the curing process, when the resin layer 204 reaches an appropriate viscosity, a transfer sheet 206 is applied to the resin layer 204 with a design 208 being laid face down in contact with the resin layer 204.
As the resin layer 204 cures, the design 208 is transferred to the resin layer 204, apparently by the process of chemical absorption. The transfer sheet 206 is then carefully removed from resin layer 204, revealing the transferred design 208 on the resin layer 204. The printed resin layer 204 will remain pliable for some period of time, making it easy to trim or cut with a simple knife 210 for various applications.
Accordingly, product 220 has a wide variety of uses and applications and may be affixed to many different materials, including stone, wood, composites, metal, cement, brick, and glass, for many decorative purposes. Resin strips may also be used for covering exposed strip surfaces after cutouts were made in various substrates. The resin strips may be cured in a hardened form or may remain flexible until final application. Alternately, a resin sheet made according to this method may be used to overlay any type of surface.
Looking now at
As shown in
At a selected time, the transfer sheet 242 is peeled off the resin layer 240 leaving a design 244 on the top side of the final resin layer 240. Likewise, as shown in
The final product 246 is best seen in
As used herein, the term “mold” may take many shapes and forms. The term includes, without limitation, a table with sides, a deeper mold for various specialty items, and a flat surface or film that may or may not be framed in some manner to define a mold area.
Referring now to
There are many materials that may be used as substrates in connection with the present invention. Natural materials, such as wood and stone, may be used only with the embodiments shown in
For substrates, various types of polymeric materials are available typically utilizing various types of resin matrix and filler. The resin may be a polyester-type resin, and the filler may be of calcium carbonate, alumina tri-hydrate (ATH), similar inorganics, or fiberglass. In the construction industry, cultured marble is used in many applications, particularly in kitchens, baths, and entryways, to achieve a marbled look. Cultured marble is made by combining a matrix of specially formulated resin, ground calcium carbonate (limestone), powder pigments for color, and a hardening agent, such as methyl ethyl ketone peroxide (MEKP), acetyl acetone peroxide (AAP), or similar curing agent.
Other materials that may used as substrates and/or coatings include phenolic mixtures, melamine formaldehyde, unsaturated polyesters, vinyl esters, epoxies, cross-linkable acrylics, and polyurethanes. In addition other thermo-set resins may be used, depending upon their properties, in addition to thermoplastic resins, which are applied as melts or solutions. These thermoplastic resins may include, but are not limited to, polyethylene, polyethylene terephthalate (PET), polypropylene, nylon, polystyrene, poly methyl methacrylate (PMMA or acrylics), and polycarbonates. Clear coat materials may be various types of resins having the capability to provide protection from sunlight fading, water resistance, color-fastness, stain resistance, wear and cleanability, and chemical resistance.
Transfer media for use in the present invention include paper, vinyl, fabric, and polymeric film. For forming an image on transfer media, sublimation dyes of all types may be used, which vaporize when heated. However, in the present invention, image transfer is accomplished without elevated temperatures. Accordingly, any ordinary ink may also be used, such as solvent-based pigment inkjet inks, solvent-based dye inkjet inks, aqueous-based pigment inkjet inks, aqueous-based dye inkjet inks, dye diffusion thermal transfer inks, chemical toner, thermal wax transfer inks, and the like.
In this example, the process described above with respect to
A printed transfer medium having a pigment ink design thereon was laid face down on the gel resin, and the air bubbles were pushed out with a smoothing bar as the medium made contact with the resin. The medium was allowed to remain on the resin gel for 20-40 minutes. Separate test strips were used to determine when absorption was complete. The medium was carefully peeled off the resin.
The printed resin was then ready to serve as a coating for a substrate. A cultured marble matrix was mixed, comprising resin, inert calcium carbonate filler, pigment, and initiator. The matrix was allowed to gel for 20-28 minutes. The finished product was removed from the table and post-cured for an hour at 180° F. to enhance hardness and stain resistance of the top coat.
In this example, the process described above with respect to
A printed film with a pigment ink design thereon was placed face down on the gel surface. The printed film was left on the resin gel for about 20 to 40 minutes. Test strips were used on extra resin to determine the optimal point of absorption. When absorption was complete, the film was carefully pulled back from the resin surface.
The printed resin surface with the uncoated film backing was cut into strips of varying sizes. The pliable snips were applied to a substrate, and the film backing was released, leaving a glossy finished surface with an ink image embedded about 35-49 mils behind the surface of the coating, protecting the image from abrasion.
From the foregoing description, the advantages of the various embodiments of the present invention can be seen. By applying image transfer media to polymeric substrates and polymer coatings, one can cause the transfer of images directly to substrates and coatings using chemical absorption characteristics that are evident during the curing processes. Accordingly, expensive and cumbersome heat presses and other means of applying heat and pressure to the transfer media are not needed.
Moreover, expensive sublimation inks and their associated specialty coated receptive materials are not needed. Instead, inexpensive solvent- or aqueous-based inks may be used to apply images to generic, inexpensive transfer media. If pigmented inks are chosen, the need for UV-resistant coatings is mitigated, thus reducing the number of requirements placed on the protective overcoat. If dye-based inks are chosen, UV-resistant materials may be incorporated into the protective overcoat as the application allows. In either case, the protective overcoat provides oxidation protection to the image, along with improved aesthetics.
The number of manufacturing steps and the time required for making prior art imaged structures are substantially reduced, since the imaging and curing processes may be simultaneously carried out. In addition, the manufacture of thin imaged resin layers opens up many additional applications to many natural and man-made materials.
Because the transfer of the image is by chemical absorption, a larger variety of printing substrates are possible than in other printing-transfer methods. Hence, printing need not be restricted to the often expensive limited set of printing substrates that are required in other printing-transfer methods.
The ability to use chemical transfer broadens the variety of inks available for use. This reduces cost and allows for changes in ink and printing technology which are likely to give even further improvements in the print quality available.
Many applications are available for the present invention. In homes, the materials may be used for kitchen and bathroom surfaces, such as countertops, vanity tops, sinks, bathtubs, showers, tub splashes, window sills, architectural surfaces, picture substrates and frames, bathroom implements, soap dishes, shower seats, shampoo shelves, and the like. In addition, the materials of the present invention may be applied to entryway structures, walls and other surfaces, table and desk tops, and visual display surfaces such as signage, artwork, murals, and award and recognition items.
Furthermore, since the print-transfer can be done with a variety of resins and is independent of the materials that might be used to back the resin, this technology can be used for fiber reinforced products such as, to name only a few, wall panels, boats, tubs and showers, architectural forms (such as columns, facades, etc.), sporting goods to which a design or a logo might be attached, and even aerospace products wherein a design or other printed coating would be desirable.
This method of print-transfer also provides a means of enhancing or replacing normal painting processes. Instead of painting a polymeric surface, that surface can be achieved by print-transferring the color (which could include a pattern) onto the polymeric surface and therefore avoid the need for additional painting. This process has the advantage of protecting the colored/printed surface by a layer of resin. Thus, for example, with airplanes, the use of a polymeric surface prepared according to the present invention may eliminate the need for paint, resulting in a weight reduction and lower maintenance.
Although the above embodiments are representative of the present invention, other embodiments will be apparent to those skilled in the art from a consideration of this specification and the appended claims, or from a practice of the embodiments of the disclosed invention. It is intended that the specification and embodiments therein be considered as exemplary only, with the present invention being defined by the claims and their equivalents.
This application is a continuation of U.S. patent application Ser. No. 11/726,727, filed on Mar. 21, 2007 and titled “METHODS FOR APPLYING IMAGES TO RESIN MATERIALS,” the entire disclosure of which is by this reference, incorporated herein.
Number | Date | Country | |
---|---|---|---|
Parent | 11726727 | Mar 2007 | US |
Child | 13854069 | US |