1. Field of the Disclosure
The present subject matter relates to heat transfers that feature anti-dye migration enhancements, particularly for use on color dye sublimated apparel such as sportswear fabrics, clothing and accessories. The present subject matter is especially suitable for transfers having a color ink layer protected by a support sheet suitable for use in heat-transferable labeling and the like.
2. Description of Related Art
Transfer decoration, labels, patches, tags, identification placards, embellishments and the like are widely used for a variety of different applications including logos, trademarks, keyboard symbols, whether numeric, alphabetic or alphanumeric or other symbols, sports designs, logos and names, clothing design details, accents and backgrounds, artwork and the like. In some applications, these decorative components are in the nature of heat transfer labels suitable for application on color dye sublimated fabrics, clothing and accessories. Such decorative components often concern so-called “soft goods,” a term generally understood in the art. Examples include clothing, upper bodywear, lower bodywear, headwear, footwear, outerwear, underwear, garments, sportswear fabrics, other sheet goods, banners, flags, athletic or sport clothing and uniforms, government uniforms, organization uniforms, accessories (e.g. belts, hats, scarves, etc.) therefor and combinations thereof.
Production of such soft goods or the like can include the use of dye sublimation techniques for fabrics. It is recognized that dye sublimated fabrics are remarkable due to their vivid color appearance, while being flexible in process manufacturing. These can be referred to as sublimated fabrics, which typically use heat-resistant synthetic fabrics that allow dyes of the “disperse dye” category to diffuse in the fabric fibers when subjected to heat. Typical synthetic fibers suitable for such a dye diffusion approach include polyesters, polyamides, nylons, and combinations of such materials with cotton and/or stretchable or resilient materials such as spandex or elastane or Lycra® and the like. Sublimated fabrics are a particular challenge for heat transfer labels, the significant challenge being that diffusion-driven dyes have a tendency to migrate from the base fabric and can migrate to and through the transfer or label, thereby altering its face color or intended appearance as well as impacting or damaging the appearance of the surrounding fabric. It is believed that the dye diffusion process is thermodynamically driven by the dye concentration gradient and that same is facilitated by heat encountered from a variety of sources during manufacture and use.
The art has recognized that this problem can be addressed through the use of anti-dye migration techniques. Such techniques can include the use of a so-called barrier layer that is often positioned in contact with the label or heat transfer when applied to the fabric. Often dye migration resistant heat transfers or labels feature a barrier layer based on highly chemically absorbent materials such as activated carbon. Even with such advances, dye diffusion often occurs along the outer perimeter of the heat transfer or label, creating what is at times referred to as the “halo effect” creating an undesirable ring around the outside of the transfer.
Following are examples of previous attempts to solve the “halo effect” problem. U.S. Patent Application Publication No. 2012/0121869 includes a dye migration preventing layer in a decoration piece, this layer being arranged between the decoration piece and the lower layer typical for such a decoration piece that can take the form of an emblem, badge, appliqué, sticker or the like. Such a decoration piece when used is attached to polyester fabric such as clothing dyed by using dispersion dye or sublimation printing. One of the features of this approach is to insure the dye migration preventing layer has an outer profile that is the same as that of the decoration or design piece.
Dinescu et al. U.S. Patent Publication No. 2012/0040154 combines a breathability feature with heat transfer labels that include a dye blocking layer as well as a so-called white layer, along with a clear layer, this labeling approach being intended for fabric containing thermal sublimation dyes. This recognizes that a thermal sublimation dye will migrate through the adhesive layer on which the label is attached to the fabric and into the white layer or the indicia layer when heated, such as during thermal transfer processing, which can cause the color of the white layer or the indicia layer to be contaminated. By this approach, the dye blocking layer is provided in an effort to stop the thermal sublimation dye from contaminating the white layer or the indicia layer. Such dye barriers include the use of activated carbon.
U.S. Pat. No. 7,238,644 concerns a laminate for printing in order to color a resin layer by allowing a sublimable dyeing agent to permeate into the inside of a resin layer through heating. This laminate includes an inner layer that is a coloring resin layer having strong affinity with a sublimable dyeing agent in an attempt to prevent transfer of the dyeing agent and of the sublimable dyeing agent having been printed.
FIG. 1 illustrates a typical prior art transfer or heat transferable label assembly that incorporates a barrier layer. This transfer includes a support portion, generally designated at 21, releasably secured to a transfer label portion, generally designated at 22. A release layer 23 overlies a carrier layer 24 of the support. A color ink layer 25 of the transfer is applied over a so-called white ink layer 26, positioned between the color ink layer and an adhesive layer 27. The barrier layer 28 is positioned between a substantial portion of the interface between the white ink layer and adhesive layer, with the barrier layer being spaced inwardly from the edge of the label in order to avoid visual detection of the activated carbon-based barrier 28 outside of the white background layer.