Process for heat setting polyester fibers for sublimation printing

Abstract

The processes and articles of the present invention use thermally stable and loft retentive polymers in sublimation printed flock fibers, which are particularly attractive for forming molded and heat laminated articles. The process and articles use high, medium and low energy dyes on the fibers. A preferred polymer for use in the fibers is poly(cyclohexylene-dimethylene terephthalate). The fibers are heat set before sublimation printing.

Description

CROSS REFERENCE TO RELATED APPLICATION [0001] The present application claims the benefits under 35 U.S.C. Section 119(e) of U.S. Provisional Patent Application Ser. No. 60 / 704,754, filed Aug. 1, 2005, to Abrams, which is incorporated herein by this reference.FIELD OF THE INVENTION [0002] The present invention is related generally to printing of flocked articles and specifically to sublimation ink printing of flocked articles. BACKGROUND OF THE INVENTION [0003] Flock is used in the manufacture of numerous types of articles, such as textiles. Flock is a short precision cut or pulverized natural or synthetic fiber used to produce a velvet-like coating on cloth, rubber, film, or paper. Flock generally has a length between about 0.010 to 0.250 inches (0.25 mm to 6.25 mm). [0004] Flocked articles are typically manufactured by electrostatically depositing the flock onto the desired surface. In one process, the desired surface is a release-adhesive coated sacrificial carrier sheet. The free...

AI Technical Summary

Benefits of technology

[0009] Heat setting may or may not be done while the fiber is uniaxially or biaxially oriented and / or under tension and is preferably performed to fibers that are crystalline, with crystallinity referring to a fiber that is more than about 50% crystalline (and less than about 50% amorphous). More preferably, the orientation is performed before heat setting. As will be appreciated, heat setting the polymer crystallizes the fiber and can impart shape memory to the fiber, thereby preventing it, during sublimation printing, from shrinking back to an original unstretched shape and deforming into an undesired shape and locking in a desired molecular orientation.

[0015] The flock of the present invention, when combined with the various flocking techniques set forth herein, can provide a wide format design inexpensively and in high volumes, particularly using sublimation ink transfer printing. Unlike certain other polyesters, the flock of the present invention can withstand the high temperatures and pressures used during sublimation transfer printing while maintaining the loft, flexibility, resilience, and plush appearance of the fibers. Typically, the shrinkage experienced by the flock fibers during sublimation ink printing, including heat lamination or sublimation transfer printing, is no more than about 5% and even more typically is no more than about 2.5% in length. Such designs are particularly attractive when combined with highly resilient flock such as thermally modified PCT. When compared to PET flock fibers, PCT flock fibers shrink much less, are able to withstand higher temperatures without deforming, and can tolerate a higher thermofixing temperature range due to PCT's higher deformation and / or melting temperature. Due to high wear / abrasion resistance, thinness, and color fastness of the printed articles of certain embodiments of the present invention, the printed articles of the present invention are useful for a wide variety of applications, including application to automotive interiors, cellular telephone covers, computer key pad and other touch surfaces, membrane-type molded films, and the like. PCT, being a type of polyester, can adhere well to many coatings and finishes that non-polyester fibers, such as nylon, are not capable of permanently adhering for prolonged periods. For example, PCT is able to accept stain-resistant coatings such as Scotchgard™ and can accept a softening finish.

Problems solved by technology

The use of sublimation ink printing of flock has generally not been widely practiced because it has produced a very low quality product.

Some polyester flock fibers, such as poly(ethylene terephthalate), can hold the dye but have a low deformation temperature, little loft retention, poor shape memory and flatten out during sublimation ink printing and are not heat-settable or soft.

Other polyester flock fibers typically melt or soften and deform under the high temperatures experienced during sublimation ink printing, losing desirable tactile characteristics (soft touch and plushness).

Nylon and rayon flock fibers, though having loft retention, generally are unable to accept the vaporized dye consistently and / or permanently and therefore produce an irregular and / or unstable colored product and offer designers a limited color palette.

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