WO2004056580A1

WO2004056580A1 - Fabric optimised for receiving high definition prints

Info

Publication number: WO2004056580A1
Application number: PCT/AU2003/001701
Authority: WO
Inventors: Ray Everson
Original assignee: Colorscreen Print Pty Ltd
Priority date: 2002-12-20
Filing date: 2003-12-19
Publication date: 2004-07-08
Also published as: AU2002953461A0

Abstract

A fabric optimised to receive, retain and display a high definition print comprising at least three layers, a first layer (C) being an absorbent material, a second layer (B) being an adhesive layer, and a third layer (A) being a printing receiving material.

Description

FABRIC OPTIMISED FOR RECEIVING HIGH DEFINITION PRINTS

Field of the Invention

The present invention relates to fabrics and in particular to fabrics which are optimised to receive, retain and display high definition prints. Background Art

Printing or otherwise displaying images on fabrics is well known. Typically the fabrics are absorbent to a certain extent in order to receive the image, particularly when the image is printed onto the fabric.

Current options for applying an image to a fabric include weaving the image into the material during manufacture. This process utilises differently coloured yarns and required strict control over the weave pattern. Without strict control over the weave pattern, the quality of the image displayed on the fabric suffers. The weaving process is used mainly on large runs due to the high set-up costs. Additionally, the quality of the image will generally not be particularly high due to the limitation of the definition of the weave.

Another process that can be used is embroidery. This is a slow process involving a laborious setup and is limited in the number of colours which can be used.

The most popular method of applying images to a fabric has been screen printing. In the screen printing process (also known as porous printing), the image is transferred to the fabric by pushing ink through a porous mesh which carries the pictorial or typographic image. The process can be divided into three major steps: prepress, press, and postpress.

Prepress operations encompass that series of steps during which the idea for a printed image is converted into an image carrier, that is the screen. Prepress operations include composition and typesetting, graphic arts photography, image assembly, and image carrier preparation. Press refers to actual printing operations. Postpress primarily involves the assembly of printed materials and consists of binding and finishing operations.

One problem with the screen printing process is that the ink forms a solid section on the surface of the fabric. The inked section is no longer absorbent, is prone to cracking and can be uncomfortable or irritating when worn.

Another advance in fabric printing was the advent of the dye sublimation process. Dye sublimation actually penetrates the fibres of the fabric. As a result, it is permanent, and cannot be felt by a user when a garment is worn. The dye sublimation process is capable of high definition, full colour image application but is generally not suitable to a towel-like fabric due to the coarseness the fabric.

A fabric adapted to be particularly advantageous when using a dye sublimation printing process has been described in the prior art. This towel has a first side particularly adapted to be a printing receiving side comprises a spine or warp which comprises a web of material from which extends on either side loops of material, the loops on the printing receiving side comprising loops of printing receiving material. The loops on the reverse side comprise loops of absorbent material.

One of the main problems encountered when using the prior art fabric is the "bleed-through" effect encountered when the dye used in the sublimation printing process, bleeds through the loops on the printing receiving side, and into either the web or spline or the loops on the reverse side of the fabric, or both. This can lead to distortion of the image or a loss in definition in the image being applied.

Another problem which may be faced when using the prior art fabric is that the sides of the fabric may be so well adapted to performing their desired function (either print receiving or absorbing) that they are not adapted to the reverse function. For example, whilst the printing receiving side is well adapted to receive printing dye, it may not perform the absorbing function of the reverse. This results in a user having to determine which side of the fabric is which in order to position the fabric for use. In certain circumstances, this can be difficult or inconvenient, for example, when the fabric is used as a towel. In that situation, one side is particularly absorbent when drying, and the other is not. Use of the non-absorbent side as an absorbent side can lead to lessened efficiency.

It can therefore be seen that a need for a fabric which is particularly adapted for use in a dye sublimation printing process which addresses the "bleed- through" effect.

It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

Summary of the Invention The present invention is directed to a fabric optimised to receive, retain and display a high definition print, which may at least partially overcome at least one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice.

In one form the invention resides in a fabric optimised to receive, retain and display a high definition print comprising at least three layers, a first layer being an absorbent material, a second layer being an adhesive layer, and a third layer being a printing receiving material.

Generally, there will be at least three or five layers depending upon whether the fabric is to receive print on both sides, h a single printed side fabric, the three layers will typically be an upper, print receiving layer, a middle adhesive layer and a lower absorbent layer. The terms "upper" and "lower" are used in this context to mean that the upper side or layer will be the side displayed, while the lower side or layer will be worn next to the skin (when the fabric is used in a garment) or placed on a surface. As stated earlier, a three layered fabric may be particularly adapted to receiving a print on one side and a five layered fabric may be particularly adapted to receiving a print on both sides of the fabric. In a five layered fabric, the five layers may preferably comprise an upper, print receiving layer, an upper-middle adhesive layer, a central absorbent layer, a lower-middle adhesive layer and a lower, print receiving layer.

Due to the construction of the fabric according to the present invention, the absorbent layer is generally available to perform its function when placed on or adjacent a surface. Fluids of liquids to be absorbed can also permeate into the print receiving layer(s). The sublimation dye however, generally penneates only into the print receiving layer(s), minimising or substantially preventing the "bleed through" effect. Typically, the fabric is laminated prior to undergoing the dyeing or printing process. The printing receiving layer(s) may however, be printed on prior to lamination.

The absorbent layer may generally be a knitted cotton or the like. It is anticipated that a variety of fabrics may be used to form this layer.

The adhesive layer may be a heat activated adhesive or a sensitive contact adhesive or the like depending on the laminating process used to form the fabric. The printing receiving layer preferably comprises a smooth fabric with a fine texture. One particularly preferred material is VISA^® fabric which generally comprises a dacron polyester. Other examples of materials suited to this purpose include any type of polyester fabric, polymide 6, polymide 6.6, any treated natural fabric or a fine felt. The fabric used may be further treated to increase the absorbency thereof.

The layers provided are generally brought together in a lamination process to form a single fabric having a number of layers. The fabric is highly absorbent and readily receives, retains and displays high definition prints, particularly when the dye sublimation printing process is used.

Preferably, the printing is applied to the printing receiving side of the fabric using a dye sublimation process.

The printing may be line art or multi-colour process graphics including reproduction of photographs. It may comprise or include lettering, patterns, images, or combinations of these. Sublimation printing processes generally involve the printing of a design on a paper backing sheet using conventional printing techniques. Sublimation inks are then employed and are transferred under heat and pressure to a printing receiving face or layer.

A dry release sublimation transfer may be used which generally includes a temporary backing sheet, the temporary backing sheet having deposited thereon a sublimation transfer design layer formed of one or more sublimation transfer inks, and a polymeric coating disposed in contact with the design layer. The so- formed sublimation transfer is then applied to a substrate layer or fabric to be decorated, under heat and pressure with the backing sheet up so that either the polymeric coating or the design layer, depending upon the specific embodiment employed, contacts the substrate layer or fabric. Application of heat and pressure to the sublimation transfer causes the polymeric coating to soften and penetrate into the substrate while causing the sublimation transfer inks in the design layer to vaporize and be deposited on the substrate layer or fabric and be retained in and on the substrate layer or fabric by the polymeric coating. Upon cooling of the substrate and the design layer and polymeric coating, the polymeric coating securely bonds the design layer to the substrate. The temporary backing sheet may include a release coating and the sublimation transfer design layer is deposited on the release coating and thereafter the polymeric coating is deposited on the design layer. Thus, when employing the preferred sublimation transfer for decorating a substrate, the sublimation transfer will be positioned on the substrate with the polymeric coating forming a layer between the substrate and the sublimation transfer design layer.

Additionally, the temporary backing sheet may include a release coating to facilitate release of the polymeric coating and design layer therefrom and the polymeric coating is first deposited on the release coating and thereafter the design layer is deposited on the polymeric coating. In such an embodiment, when the dry release sublimation transfer is employed for decorating a substrate, the sublimation transfer will be positioned on the substrate so that the design layer thereof contacts the substrate.

The temporary backing sheet, which preferably includes a release coating thereon, may further include a first polymeric coating layer deposited on the release layer, a sublimation design layer deposited on the first polymeric coating layer, and a second polymeric coating layer deposited on the design layer.

With respect to each of the above dry release sublimation transfers, the sublimation transfer design layer is preferably printed or laid down on the release coating of the temporary backing sheet by offset printing, digital printing or screen printing, the latter method being employed when there are only a relatively small number of different sublimation ink colours in the design layer, and the polymeric coating is printed or laid down on the design layer or the release layer of the temporary backing sheet, depending upon the particular configuration of the final dry release sublimation transfer, by offset printing, digital printing or screen printing.

The method for decorating the substrate layer or fabric typically includes the steps of providing a dry release sublimation transfer comprising any of the various embodiments thereof described above, positioning the dry release sublimation transfer on a substrate to be decorated with the temporary backing sheet disposed away from the substrate, and applying heat and pressure to the dry release sublimation transfer, thereby causing the polymeric coating to soften and penetrate into the substrate, while releasing the temporary backing sheet from the design layer. Thereafter, the design layer and polymeric coating and substrate are cooled, for example, by exposure to ambient air, whereby the polymeric coating securely bonds the design layer to the substrate.

The temporary backing sheet may comprise a suitable sheet material which is relatively non-porous and substantially impervious to the release layer when the latter is in softened or molten condition. For example, the temporary backing sheet may comprise a paper backing sheet, preferably of the parchment type. However, other materials may be employed in place of paper, such as fiberglass cloth, plastic film, for example, polytetrafluoroethylene, cross-linked phenol-formaldehyde resin, and cross-linked urea-formaldehyde resin, or a thin metal foil or a woven or non- woven fabric, as will be apparent to one skilled in the art.

As indicated above, the dry release sublimation transfer can preferably include a release layer disposed on the backing sheet. The release layer must be formed of a material which is solid at room temperature and which when heated to the temperatures normally encountered during heat release application of the dry release sublimation transfer of the invention, will soften so that the backing sheet may be easily removed from the remainder of the transfer after application of the transfer to the substrate to be decorated. Thus, the release layer may comprise a wax coating formed of a relatively high melting point wax of vegetable or mineral origin, e.g. vegetable wax having a melting point of from about 55°C to about 70°C or a mineral wax having a melting point of from about 80°C to about 105°C. However, instead of the vegetable or mineral waxes, normally solid polyethylene glycols having a relatively high molecular weight of at least 1000 may be employed. Such materials are wax-like solids and are sold for example by Union Carbide & Carbon Chemicals Corporation under the trademark "Carbowax." These wax-like materials can be applied in generally the same manner as ordinary wax coatings. Such normally solid polyethylene glycols have softening points in the range of from about 150.degree. F. to about 350.degree. F. so that they are capable of providing the desired heat release properties under a variety of practical operating conditions. Other examples of release layers suitable for use herein include low molecular weight polyethylenes, polytetrafluoroethylene as well as stearic acid.

The sublimation design layer 16 may be applied to the release layer 14 of the backing sheet 12 as one or more layers of an organic base sublimation ink or a water-soluble sublimation ink comprising a sublimation dye, such as a disperser dye, including encapsulated dyes, having a sublimation point between 100°C and 300°C; a thickener, such as water-soluble colloids, for example, methyl cellulose, sodium carboxymethyl cellulose, carboxymethyl cellulose, or hydrophobic materials such as polyvinyl acetate, polyvinyl chloride, polyketone resins and the like; and sodium alginates; and water. The amount of dye employed is generally determined by the required depth of shade.

Depending upon the type of substrate to be decorated, in accordance with the invention, the polymeric coating may be applied in an amount to produce a layer having a thickness within the range of from about 0.1 to about 20 mm and preferably from about 0.2 to about 10 mm.

The polymeric material suitable for use herein may comprise homopolymers, copolymers, or terpolymers having the above-mentioned glass temperature and molecular weights such as acrylic polymers, styrene polymers, vinyl polymers, and copolymers and terpolymers thereof including copolymers of butyl acrylate and methyl acrylate, acrylonitrite-butadiene-styrene terpolymers, copolymers of vinyl isobutyl ether and methyl methacrylate, copolymers of ethyl acrylate and methyl or butyl methacrylate, copolymers of vinyl acetate and butyl acrylate, methyl acrylate polymers, copolymers of vinyl chloride and ethylene, copolymers of butyl acrylate and methyl methacrylate, copolymers of butyl acrylate and butyl methacrylate, copolymers of ethylene and vinyl acetate, copolymers of styrene and 1,3, -butadiene, copolymers of vinyl isobutyl ether and methyl methacrylate. Other polymers suitable for use herein include poly n-butyl methacrylate, polyvinyl acetate, poly n-propyl methacrylate, polyethyl methacrylate, polyvinyl chloride, polyacrylonitrile, polystyrene, polymethyl methacrylate, polyethyl acrylate, poly n- propyl acrylate, poly n-butyl acrylate, and polyisobutylene.

The polymeric coating materials may also include one or more suitable conventional plasticizers in an amount ranging from about 2 to about 10% by weight to impart increased flexibility thereto as well as lower the glass temperature thereof. Examples of plasticizers suitable for use herein include dioctyl phthalate, tricresyl phosphate, chlorinated biphenyl, dibutyl sebacate, dibutyl phthalate, dimethyl phthalate, and glycerol. hi employing the dry release sublimation transfer as previously described to decorate a substrate material, the transfer is generally applied so that either a polymeric coating or the sublimation design layer itself, directly contacts the substrate so that the backing sheet faces upwardly away from the substrate. Thereafter, heat and pressure are applied to the backing sheet, such as by employing a conventional iron or press or even a vacuum press, whereby the dry release sublimation transfer is heated to a temperature within the range of from about 90°C to about 230°C, and preferably from about 175°C to about 220°C, under a pressure within the range of from about 2 to about 100 psig, and preferably from about 4 to about 50 psig, for a time ranging from about 7 to about 80 seconds and preferably from about 20 to about 40 seconds. At this time, the backing sheet is released from the remainder of the transfer leaving the sublimation design layer and polymeric coating layer adhered to the substrate to be decorated. Thereafter, the substrate including the polymeric coating and sublimation design layer are allowed to cool, for example, by blowing ambient air over the same. Upon cooling, the polymeric coating layer tightly bonds the sublimation design to the substrate. The substrate will thereby be decorated with the sublimation design, which design will be sharp and clear and be composed of bright, pleasing colours. In fact, the transferred design will be substantially brighter and more vivid than the design layer carried by the dry release transfer of the invention. It is believed that during the transfer process described above, the heat applied to the dry release transfer transforms the sublimation inks of the design layer (which are dull and drab in appearance) to vapours, such vapours contacting the substrate to be decorated and solidifying thereon to from a design having the desired bright colours.

Brief Description of the Drawings Various embodiments of the invention will be described with reference to the following drawings, in which:

Figure 1 is a schematic section view of the layers and the order of layers prior to lamination according to an embodiment of the invention.

Figure 2 is a schematic section view of a three layer, single print side fabric post-lamination. Figure 3 is a schematic section view of a five layer, double print side fabric post-lamination.

Detailed Description of the Invention According to the invention, a fabric optimised to receive, retain and display a high definition print is provided.

The fabric illustrated in Figure 1 comprises three layers, a first layer C being an absorbent material, a second layer B being an adhesive layer, and a third layer A being a printing receiving material. The three layer fabric embodiment is adapted to receive print on only one side. In a single printed side fabric such as that illustrated in Figure, the three layers are an upper, print receiving layer A, a middle adhesive layer B and a lower absorbent layer C. The terms "upper" and "lower" are used in this context to mean that the upper side or layer will be the side displayed, while the lower side or layer will be worn next to the skin (when the fabric is used in a garment) or placed on a surface.

The five layered fabric embodiment, illustrated in Figure 3, is particularly adapted to receiving a print on both sides of the fabric, hi a five layered fabric, the five layers comprise an upper, print receiving layer, an upper-middle adhesive layer, a central absorbent layer, a lower-middle adhesive layer and a lower, print receiving layer.

Due to the construction of the fabric according to the present invention, the absorbent layer is generally available to perform its function when placed on or adjacent a surface. Fluids of liquids to be absorbed can also permeate into the print receiving layer(s). The sublimation dye however, generally permeates only into the print receiving layer(s), minimising or substantially preventing the "bleed through" effect. Typically, the fabric is laminated prior to undergoing the dyeing or printing process. The printing receiving layer(s) may however, be printed on prior to lamination. The absorbent layer C is a knitted cotton or the like. The adhesive layer

B is a heat activated adhesive. The printing receiving layer A is a smooth fabric with a fine texture, preferably VISA^® fabric which is a polyester or it may be a treated natural fabric.

The layers provided are brought together in a lamination process to form a single fabric, shown in Figure 2, having a number of layers. The fabric is highly absorbent and readily receives, retains and displays high definition prints, particularly when the dye sublimation printing process is used. The printing is applied to the printing receiving side of the fabric using a dye sublimation process, an outline of which is given hereinafter as an example only.

The printing may be line art or multi-colour process graphics including reproduction of photographs. It may comprise or include lettering, patterns, images, or combinations of these. Sublimation printing processes generally involve the printing of a design on a paper backing sheet using conventional printing techniques. Sublimation inks are then employed and are transferred under heat and pressure to a printing receiving face or layer. A dry release sublimation transfer may be used which generally includes a temporary backing sheet, the temporary backing sheet having deposited thereon a sublimation transfer design layer formed of one or more sublimation transfer inks, and a polymeric coating disposed in contact with the design layer. The so- formed sublimation transfer is then applied to a substrate layer or fabric to be decorated, under heat and pressure with the backing sheet up so that either the polymeric coating or the design layer, depending upon the specific embodiment employed, contacts the substrate layer or fabric. Application of heat and pressure to the sublimation transfer causes the polymeric coating to soften and penetrate into the substrate while causing the sublimation transfer inks in the design layer to vaporize and be deposited on the substrate layer or fabric and be retained in and on the substrate layer or fabric by the polymeric coating. Upon cooling of the substrate and the design layer and polymeric coating, the polymeric coating securely bonds the design layer to the substrate.

With respect to each of the above dry release sublimation transfers, the sublimation transfer design layer is normally printed or laid down on the release coating of the temporary backing sheet by offset printing, digital printing or screen printing, the latter method being employed when there are only a relatively small number of different sublimation ink colours in the design layer, and the polymeric coating is printed or laid down on the design layer or the release layer of the temporary backing sheet, depending upon the particular configuration of the final dry release sublimation transfer, by offset printing, digital printing or screen printing,.

The substrate will thereby be decorated with the sublimation design, which design will be sharp and clear and be composed of bright, pleasing colours. In fact, the transferred design will be substantially brighter and more vivid than the design layer carried by the dry release transfer of the invention. It is believed that during the transfer process described above, the heat applied to the dry release transfer transforms the sublimation inks of the design layer (which are dull and drab in appearance) to vapours, such vapours contacting the substrate to be decorated and solidifying thereon to from a design having the desired bright colours

In the present specification and claims, the word "comprising" and its derivatives including "comprises" and "comprise" include each of the stated integers but does not exclude the inclusion of one or more further integers. Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics maybe combined in any suitable manner in one or more combinations.

In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted by those skilled in the art.

Claims

Claims:

1. A fabric optimised to receive, retain and display a high definition print comprising at least three layers, a first layer being an absorbent material, a second layer being an adhesive layer, and a third layer being a printing receiving material.

2. A fabric according to claim 1 having at least three layers, adapted to receive print on a first surface only.

3. A fabric according to claim 1, having five layers adapted to receive print on a first and a second surface.

4. A fabric according to claim 2, having three layers, an upper print receiving layer, a middle adhesive layer and a lower absorbent layer.

5. A fabric according to claim 3, wherein the layers comprise an upper print receiving layer, an upper-middle adhesive layer, a central absorbent layer, a lower- middle adhesive layer and a lower print receiving layer.

6. A fabric according to claim 1 wherein at least one layer of the fabric is dyed or printed prior to lamination.

7. A fabric according to claim 1 wherein the fabric is laminated prior to undergoing a dyeing or printing process.

8. A fabric according to claim 1 wherein the adhesive layer is a heat activated adhesive.

9. A fabric according to claim 1 wherein the printing receiving material is chosen from the group comprising polyesters, polyamides, dacron polyesters and treated natural fabrics.

10. A fabric according to claim 1 wherein printing is applied to the printing receiving side of the fabric using a dye sublimation printing process.