Patent Application
20200096910
The present invention relates to the creation of photographic quality heat activated transfers and appliqués and, particularly, to a light-weight printed heat-transfer comprised of numbers, letters, logos, graphics, or other indicia.
Ink-printed heat transfers are well-known and commonly used to transfer a graphic, such as text or a figure, onto an item, such as apparel or merchandise. A transfer sheet or release sheet is usually pre-printed with a graphic, and then the graphic is transferred from the transfer sheet or release sheet to the item using a heated platen, iron or the like.
To manufacture heat transfers it is typical to apply a release layer to the transfer sheet before the graphic is printed, then print the ink graphic atop the release layer, and then coat the adhesive over the top surface of the graphic. When a user then applies the graphic to the item, the graphic transfer is turned adhesive-side down onto the item and heat is applied to the release sheet to transfer the graphic to the item from the release layer of the release sheet.
Inks and toners can be digitally printed by a variety of methods including static discharge or ink jet printing. Printing techniques such as gravure printing, offset printing, flexographic printing, screen printing, and digital printing all can be used to create a heat transfer. In all such processes the thermal adhesive(s) are generally applied after the printing process using a screening process, which is not done in a digital manner. Rather, a template (screen) is required to expose an area specific to each graphic. This requires an offline manufacturing process to create a screen for selectively applying the adhesive, interruption of the digital processes, and therefore significantly contributing to the fixed cost of any change in shape between graphics and lowering the productivity of the operation by increasing change-over time. In contrast, the apparel industry increasingly requires quick-change, low-inventory production of custom articles in small batches with low turnaround time, while keeping inventory at a minimum. Additionally, the offline screen manufacturing process is highly reliant on environmentally damaging chemicals. Increasingly customers and brands are seeing value in reducing the environmental impact of their products.
New printing methods have evolved such as the HP Indigo® proprietary liquid electrophotography system to print the graphic. Liquid electrophotographic (LEP) inks currently used in digital printing presses typically employ a pigment in a carrier, usually a hydrocarbon-based carrier, such as an isoparaffinic liquid (e.g., ISOPAR®). The LEP inks include a resin, as well as other ink components for adjusting various desirable properties. The resin holds the pigment on the print media. However, this method may also rely on screen printed polymeric coating intermediaries between the printed graphic and the adhesive. The production of screens is a time consumptive process and the associated clean up and reuse of screens produces undesirable environmental harmful waste byproducts that must be disposed.
Until now heat transfer manufacturers have not determined a successful process to provide a fully digital transfer, and therefore they are held to the aforementioned unattractive large minimum manufacturing quantities. To avoid these large minimums, companies can request a set up charge for small order quantities, which is also undesirable for the customer. Significant time and production overhead could be saved if adhesive could be applied as a step in a fully-digital printing process.
One attempt to do this employs a laser printer to print toner onto a sheet. This method then presses an adhesive coated paper to the print where the adhesive only sticks to the digitally printed areas, and then use those layers in conjunction with an opaque layer as the final transfer decoration. See U.S. Pat. No. 8,236,122. Generally, the laminating conditions used in this process have very small tolerances that are not necessarily achievable on a regular basis. Additionally, the processing time to adhere the adhesive to the print is substantial, on the order of 30 seconds per sheet, which cannot compare to the speed of production of a high speed laser or inkjet printing.
An alternative method involves the deposition of adhesive on a release substrate. The deposited adhesive is then pressed in a secondary process, offline to the printing process, onto the toner printed side of the printed release liner. See, for example, U.S. Pat. No. 9,227,451 issued Jan. 5, 2016. This secondary process is also more time consumptive.
What is needed is a more efficient method of digitally printing a graphic and then subsequently fusing a thermal adhesive to the printed graphic.
According to embodiments of this invention, a heat transfer and method for manufacturing the same can efficiently provide a unique-graphical hot transfer well suited for customization of apparel and soft goods.
A digitally produced heat transfer can be manufactured by digitally printing an image onto a protective coating that is receptive to ink and/or toner to form a printed area and an unprinted area of the protective coating, and digitally printing an attractant precisely onto the printed area and not onto the unprinted area. An adhesive powder can be applied onto the printed area and the unprinted area. The adhesive powder can then be removed from the unprinted area lacking any attractant and the remaining adhesive powder can be bonded to the printed area.
A digitally produced heat transfer can include a protective coating that is receptive to ink and/or toner, a digital image printed onto the protective coating to form a printed area and an unprinted area of the protective coating, an attractant digitally printed precisely onto the printed area and not onto the unprinted area, and an adhesive powder applied onto the attractant and not onto the unprinted area of the protective coating.
It is, therefore, an object of the present invention to provide a fully-digital-printed heat transfer graphic and method of manufacture, to meet the needs of the market for smaller order quantities and customized heat transfers produced in a more environmentally friendly way.
It is yet another object of the present invention to provide a heat sealed appliqué that resembles a traditional, layered appliqué often used for lettering and numbering on sports jerseys and uniforms. And it is another object of the present invention to provide a heat sealed appliqué that can be manufactured cost effectively.
The subject matter described and claimed in one embodiment is a process for producing a digital printed heat transfer comprising the steps of: 1) obtaining a substrate having a release layer coated on one side; 2) digitally printing a graphic layer onto the release layer side of the substrate to form a printed area and an unprinted area; 3) digitally printing an attractant onto the printed area in registration therewith; 4) applying a powder adhesive layer onto the attractant; and 5) bonding the powder adhesive layer to the attractant and/or the digitally printed graphic layer. The attractant can precisely secure the adhesive powder to the printed graphical areas, and the unused powder may be removed and recycled. The adhesive powder can then be fused to the printed graphic by the application of heat and/or pressure via infrared lamps or heated rollers or a combination thereof. The resulting image can then be cooled to set the image for use as a heat transfer.
Illustrations are provided to disclose aspects of the invention and are described herein. These aspects describe but a few of the ways in which the principles disclosed herein can be applied and is intended to include all aspects and similar or equivalent methods or steps. Other advantages and novel features will become apparent from the following detailed description when considered with the drawings.
Other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments and certain modifications thereof when taken together with the accompanying drawings in which:
The present invention is process for producing a thermal or “hot” transfer by a multi-stage print process comprising the steps of: 1) obtaining a substrate having a release layer coated on one side; 2) digitally printing a graphic layer onto the release layer side of the substrate to form a printed area and an unprinted area; 3) digitally printing an attractant onto the printed area in registration therewith; 4) applying a powder adhesive layer onto the attractant; and 5) bonding the powder adhesive layer to the attractant and/or the digitally printed graphic layer. The powder adhesive may be bound onto and in registration with the digitally printed graphic by digitally printing an attractant onto the graphic as an intermediary to secure the adhesive powder thereto. The attractant temporarily and precisely secures the adhesive powder to the digital print, while excess adhesive powder can be removed and recycled. The temporarily adhering thermal adhesive powder can then be heat-fused and more permanently bonded to the digital printed graphic by the application of heat via infrared lamps or heated rollers or a combination thereof. The resulting image may be cooled to set the image for use as a heat transfer. The process produces multi-color photographic quality heat transfers suitable for the apparel and soft goods industries. With reference to the drawings, the digitally printed heat transfer and method of manufacture is disclosed in more detail.
Referring initially to the drawings,
Given the foregoing structure the heat transfer 100 may be applied to a base material. The base material can be made using a wide variety of textile fabrication methods known to the arts including wovens, nonwovens, and knits comprised of natural or synthetic fibers. Further the base material would typically be part of a clothing article or apparel such as tee shirts, jerseys, sweatshirts, outerwear, pants and slacks. More generally, heat transfers produced utilizing this method could be applied to soft goods such as apparel, home furnishings, signage such as banners and flags, luggage, back packs and automotive interiors. Before the heat transfer 100 is applied to an article the release liner 114 is removed and the adhesive coating or layer 112 is put in contact with (i.e. is directly adjacent to) the exterior surface of the article. Heat and pressure can be applied to the heat transfer 100 to bind the adhesive coating/layer 112 to the surface of the article, after which the carrier substrate 102 is removed. Protective layer 106 that is receptive to ink and/or toner can define the outer most layer of heat transfer 100 after application to the article. In some embodiments the digital printed graphic 108 and protective layer 106 may fuse or otherwise combine when heat transfer 100 is applied to the article, and the combination can define the outer most layer of the heat transfer 100 after application. The protective layer 106 can be a polymeric film containing amine functionalities, such as polyurethane or polyamide.
After fusing and heat transfer onto an article of apparel, the digitally printed graphic 108, ink receptive coating/protective layer 106 and powder adhesive 112 ideally have a proportional limit above 2% engineering strain, plus an ability to elongate within a general range of 10% to about 50% or more depending on articles of apparel. One skilled in the art should understand that certain combinations of digital printed graphic methods such as HP Indigo's process would provide such suitable range of elongation. Outerwear and home furnishings and bags by comparison would generally have a proportional limit above 1% strain, and an ability to elongate at least about 5% and could work with electrostatic toner print systems such as those by Xeikon® or ink jet printer pigment inks. Those systems by comparison crack with substantial elongation. One skilled in the art could utilize such systems by breaking larger graphics up into smaller dots to comprise the image to minimize the degree of elongation around an individual printed matrix. This would necessitate the need for digital application of the adhesive or an attractant for binding the adhesive precisely to the printed element.
At step 200 a combination protectant ink/toner receptive coating 106 is applied. The toner/ink-receptive coating 106 functions to absorb liquid-based inks, binding the liquid ink until it can fully dry, cause the ink to spread into well-formed dots on the carrier 102. Suitable inked receptive coatings include PrintRite™ ink receptive coatings available from Lubrizol®. Where required, based on ink or toner used, the toner/ink-receptive coating 106 includes or can be modified to include a protective coating. One skilled in the art will understand that the present process is equally suitable for dry toner, but in this instance an ink receptive coating 106 is not required.
At step 202 a digital printed ink or toner 108 is applied to the toner/ink receptive coating 106 using any suitable method of printing from a digital-based image.
At step 204 an attractant 110 can be digitally printed onto the digitally printed graphic 108 in registration therewith. For example, a digital printer can precisely (+/−0.5 mm) print the attractant 110 onto the printed area of the protective coating. In this manner, the digital printer prints attractant 110 substantially onto all of the printed graphic and does not print attractant 110 substantially onto any of unprinted area of the protective coating.
At step 206 an adhesive powder 112 is applied to the attractant 110 by means of scatter powder coating, direct transfer on a carrier, use of a vacuum powder transfer system, or by any other suitable means of powder deposition. The adhesive powder is preferably a thermally activated adhesive that can be polyester, polyurethane, polyolefin or polyamide based. The adhesive powder 112 adheres to the attractant 110 but only to the attractant 110, not adjacent or surrounding areas. For example, the adhesive powder does not adhere to the carrier layer 102, the release layer 104, the ink/toner receptive layer 106, or the digitally printed ink/toner layer 108. Thus, in effect, the adhesive powder 112 forms a top layer over the attractant 110 and ink/toner 108 in registration therewith.
At step 208 any excess powder is removed from the unprinted surface areas of 106 by gravity when rotated around a roller or by any other suitable means such as mechanical vibration, blowers, or brushes. The powder recovered in step 208 is preferably recycled for later use.
At step 210 the remaining adhesive 112 on the digitally printed areas of 108 and 110 is more permanently bonded, such as by drying, curing, and/or fusing using heat from infrared IR lamps, ovens, heated rollers, and/or other methods known in the art. The now-bonded adhesive 112 lies in registration over the attractant 110 and ink/toner 108. Depending on the composition of the attractant used, the attractant layer 110 may by fully evaporated or the attractant layer 110 may have a significant quantity of residual components still present between the digitally printed areas 108 and adhesive layer 112 after the completion of step 210.
At step 212 the transfer is cooled below the melt point of the adhesive powder or more preferably to room temperature and a protective release liner 114 is applied.
Normal application of the digitally-produced heat transfer 100 occurs at step 214. The digitally-produced heat transfer 100 may be applied to any article of apparel or soft goods made from textiles. One skilled in the art should understand that the above-described heat transfer 100 can be made and sold in roll form or sheet form and subsequently cut to size. Application equipment can include heat transfer presses made by George Knight model DK20SP or Stahl's Fusion® heat press.
The process described above offers a more efficient method of digitally printing a hot transfer. The process described can efficiently produce a single unique graphical transfer or rolls or sheets of same. The heat transfers produced are well suited for customization of apparel and soft goods.
The method would replace processes utilizing screens to apply polymeric coatings and adhesives thus simplifying production, eliminating time consumptive changeover processes, and reducing waste and environmental chemical disposal issues.
Having now fully set forth the preferred embodiment and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with said underlying concept. It is to be understood, therefore, that the invention may be practiced otherwise than as specifically set forth in the appended claims.
This application claims priority to U.S. provisional patent application Ser. No. 62/736,093 filed 25 Sep. 2018.
| Number | Date | Country | |
|---|---|---|---|
| 62736093 | Sep 2018 | US |
