WO2006091957A2

WO2006091957A2 - Selected textile medium for transfer printing

Info

Publication number: WO2006091957A2
Application number: PCT/US2006/006973
Authority: WO
Inventors: Samit N. Chevli
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 2005-02-24
Filing date: 2006-02-24
Publication date: 2006-08-31
Anticipated expiration: 2007-08-24
Also published as: US20060185099A1; JP2008532794A; EP1851059A2; WO2006091957A3

Abstract

This invention pertains to a method of transfer printing, in particular to a method of utilizing an inkjet printer and one or more disperse dye inkjet inks to print a transfer image onto a selected textile transfer medium, then transfer the transfer image from the transfer medium to an object to create an image on the object.

Description

TITLE

SELECTED TEXTILE MEDIUM FOR TRANSFER PRINTING

FIELD OF THE INVENTION

This invention pertains to a selected textile medium for transfer printing. It further pertains to the use of the textile medium for transferring images to three- dimensional objects. The aqueous inkjet inks used are disperse dye inks which are optimally used with the selected textile medium.

BACKGROUND OF THE INVENTION

Digital printing methods such as inkjet printing are becoming increasingly important for the printing of textiles and offer a number of potential benefits over conventional printing methods such as screen printing. Digital printing eliminates the set up expense associated with screen preparation and can potentially enable cost-effective short run production. InkJet printing furthermore allows visual effects such as tonal gradients and infinite pattern repeat sizes that cannot be practically achieved with a screen printing process.

One use of digital printing methods is to prepare printed images that can be utilized for transfer printing. In this process an image is printed onto an intermediate transfer sheet, and then the image is transferred to another surface by applying heat to the intermediate transfer sheet. Inks that achieve this purpose are often characterized as heat sensitive, dye diffusion or sublimation inks. US5830263, US6840614, US6386696, US6357870, US6200668, US6402313 and US5488907 (the disclosures of which are incorporated by reference herein in their entirety for all purposes as if fully set forth) describe various aspects of transfer printing.

The intermediate transfer sheet is generally categorized as a substrate, which may be paper or it may be another material, that will facilitate and withstand the transfer temperature, and will also facilitate bonding of the ink layer to the substrate. The predominantly used material is paper or treated papers which are well suited for transferring an image to a two-dimensional object such as a textile, more specifically a tee shirt. However, the paper or coated paper is not well suited for transferring the image to a three-dimensional object. Among the colorants used in transfer printing inks are disperse dyes which have proven to be especially useful for printing on hydrophobic fibers such as polyesters, cellulose acetate, etc. The initial choice of dye is often suggested by those disperse dyes used in screen printing. However, the need for specific disperse dye systems for digital printing of textiles require multiple levels of optimizing ink properties such as jettability, stability, shelf storage, color properties, etc. The color intensity of a digitally printed textile needs to be improved for full adoption of this printing option for textiles.

There is thus still need in the art for selected textile intermediate substrates that can be used for transfer printing. The optimum ink for this transfer printing is a disperse dye ink since such an ink can be transferred from the textile to the final printed object.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention, there is provided a transfer printing method for creating an image on an object, comprising the steps of:

(a) providing an inkjet printer that is responsive to digital data signals;

(b) loading the inkjet printer with a transfer medium to be printed;

(c) loading the inkjet printer with a first disperse dye inkjet ink suitable for printing onto the transfer medium, the first disperse dye ink containing a first disperse dye having a first activation temperature;

(d) printing onto the transfer medium using the first disperse dye inkjet ink in response to the digital data signals to create a disperse dye printed transfer image of the image on the transfer medium; and

(e) applying the printed transfer medium onto the object under temperature conditions at or above the first activation temperature, for a time sufficient to effectively transfer the disperse dye printed transfer image from the transfer medium to the object to create the image on the object,

wherein the transfer medium is a textile transfer medium that is a knitted or woven fabric comprising fibers consisting essentially of fibers selected from the group consisting of cotton, linen, ramie, viscose, lyocell, polyamide, polyolefin, polyacrylonitrile, aramid and elastene fibers, and blends of two or more thereof.

Preferably, the printer is loaded with a disperse dye ink set comprising at least two disperse dye inkjet inks suitable for printing onto the transfer medium, one of the at least two disperse dye inkjet inks being the first disperse dye ink, and another of the at least two disperse dye inkjet inks being a second disperse dye ink containing a second disperse dye having a second activation temperature; and wherein the temperature conditions are at or above the higher of the first and second activation temperatures.

More preferably, the printer is loaded with a disperse dye ink set comprising at least three disperse dye inkjet inks suitable for printing onto the transfer medium, one of the at least three disperse dye inkjet inks being the first disperse dye ink, another of the at least three disperse dye inkjet inks being the second disperse dye ink, and another of the at least three disperse dye inkjet inks being a third disperse dye inkjet ink containing a third disperse dye having a third activation temperature; and wherein the temperature conditions are at or above the higher of the first, second and third activation temperatures. When three inks are used, one ink should preferably be cyan in color, another magenta in color and another yellow in color.

In another preferred embodiment the printer is loaded with a disperse dye ink set comprising at least four disperse dye inkjet inks suitable for printing onto the transfer medium, one of the at least four disperse dye inkjet inks being the first disperse dye ink, another of the at least four disperse dye inkjet inks being the second disperse dye ink, another of the at least four disperse dye inkjet inks being the third disperse dye ink, and another of the at least four disperse dye inkjet inks being a fourth disperse dye inkjet ink containing a fourth disperse dye having a fourth activation temperature; and wherein the temperature conditions are at or above the higher of the first, second, third and fourth activation temperatures. In this embodiment, one ink should preferably be cyan in color, another magenta in color, another yellow in color, and another black in color.

These and other features and advantages of the present invention will be more readily understood by those of ordinary skill in the art from a reading of the following detailed description. It is to be appreciated that certain features of the invention which are, for clarity, described above and below in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any subcombination. In addition, references in the singular may also include the plural (for example, "a" and "an" may refer to one, or one or more) unless the context specifically states otherwise.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As indicted previously, transfer printing is in a general sense well known to those of ordinary skill in the art, as exemplified by the numerous incorporated references listed above.

The present invention is directed to using a specified textile transfer medium that can take advantage of various emerging features of the digital printing ink jet industry, and further provide a transfer medium that would be adaptable to the transfer to both two- and three-dimensional objects. The preferred application for using the selected textiles for transfer printing is for image transfer to three-dimensional objects.

Most of the transfer medium development for the transfer printing has focused on paper and adding coatings to that paper to make the paper more receptive to the initially printed image (see previously incorporated US6200668). This focus on paper and the coated paper has lead to relatively inflexible transfer media that is not well suited to transfer printing to three-dimensional objects. The paper chemicals added to the paper make it a better medium for printing by reducing the wicking of the ink jet ink into or on the fibers of the paper; however, these chemicals also make the paper less flexible and less suited for printing three-dimensional objects.

Thus, a different substrate for transfer printing is needed. One of the criteria needed for an effective transfer medium is that it must retain the image that is digitally printed. The ink cannot wick, or otherwise spread the ink jet printed dots as that would lead to a less resolved image. If the initially printed image has lost any of its resolution, this cannot be recovered when the image is transferred under the influence of heat to the final printed product. Many textiles, including those based on polyester and cellulose triacetate fibers, will not suitably retain an image and/or will not permit the disperse dye in the image to suitably transfer when exposed to post treatment.

After careful evaluation, it has been determined that certain textiles can be optimally used, particularly knitted or woven textiles, and particularly those containing fibers selected from the group consisting of cotton, linen, ramie, viscose, lyocell, polyamide, polyolefin, polyacrylonitrile, aramid and elastene fibers, and blends of two or more of these fibers. Examples of the aramid fibers include Kevlar® and Nomex® (E. I. du Pont de Nemours and Company, Wilmington, Delaware USA).

The disperse dyes chosen for these selected textiles have low substantivity for these fibers, and are the selected textile/disperse dye combinations are well matched for this transfer printing.

The choice of which textile to use as the transfer medium will depend on several factors, including the textile/ink combination that leads to both the most resolved image, but also the image which has the most color. Also the textile/ink combination is chosen to match the final image transfer requirements.

The preferred textile for the transfer printing is a knitted or woven textile containing cotton or cotton blends with fibers selected from the group consisting of linen, ramie, viscose, lyocell, polyamide, polyolefin, polyacrylonitrile, aramid and elastene fibers.

The flexibility of these selected textiles relative to paper can be described as draping, that is the selected textiles can conform to new shapes. The textiles can be optimally chosen relative to the final image transfer requirements. For example, a cotton fabric might have another more stretchable fiber woven or knitted with the cotton such that the fabric would have stretching properties. Thus, after an image is printed onto this cotton blend it could be stretched to cover a three-dimensional object for an ideal arrangement for the final transfer of the image from the printed textile to the final imaged object.

Any ink jet printer can be used to print the image onto the selected textile. Because of the flexibility of the textile, those printers which have design features that manage the use of the textiles would be preferred printers. Examples of these printers include the DuPont™ Artistri™ 2020 digital textile printing system (E. I. du Pont de Nemours and Company, Wilmington, Delaware USA), and the printer system described in US6742869 (the disclosure of which is incorporated by reference herein in its entirety for all purposes as if fully set forth).

The preferred inks for the transfer printing with these selected textiles are those containing disperse dyes as the colorant. These provide an optimum performance in printing onto the selected textiles, but also are effective for the transfer of the image during the final image transfer step.

While all disperse dyes can be used, the preferred list of CMY dyes include:

Cyan - Disperse Blue 60;

Magenta - Disperse Red 5, 75, 76, 86, 91 , 92, 121 , 127, 132, 145, 159, 164, 179, 184, 189, 191 , 229, 258, 343, 152 and 167:1 ; and

Yellow - Disperse Yellow 5, 27, 33, 42, 50, 54, 59, 79, 83, 98, 100, 114, 122, 139, 140, 160, 199, 201 , 204, 206, 224 and 231.

A disperse black dye is often a combination of several disperse dyes to produce a black color.

In addition to CYMK inks, the ink set may further comprise one or more "gamut-expanding" inks, including different colored inks such as an orange ink, a green ink, a red ink and/or a blue ink, and combinations of full strength and light strengths inks such as light cyan, light magenta and light black. These "gamut- expanding" inks are particularly useful in textile printing for simulating the color gamut of analog screen printing, such as disclosed in previously incorporated US20030128246.

The DuPont™ Artistri™ 2020 digital printing system has commercially available disperse dye inks and ink sets that are suitable for use in the present invention.

The temperature at which the image is transferred to the final object is typical for transfer printing with disperse dye inks. The range of suitable transfer temperatures and times is generally from about 150 to about 275°C, for from about 0.5 minutes to about 5 minutes. A more preferred temperature range is from about 180 to about 220⁰C, and a more preferred time range is for from about 0.75 minutes to about 2 minutes. Transfer can be further assisted by applying vacuum during the transfer process.

The selected textile/disperse dye combination provides a printed image on the selected textile that can be used to create images on three-dimensional surfaces. For example, it would be possible for an artist take a drawing or painting, or a photographer take a photograph, scan it with digital scanning process, then convert the image to a digital file that can be printed by a digital printer. The artist/photographer could use software to invert the image so that a positive image would be printed on the final three-dimensional object. Then the digital ink jet printer would create the image on the selected transfer medium and then this printed medium would be conformed to the final three-dimensional object surface. The transfer step would occur and the selected transfer medium removed leaving the image on the three-dimensional object.

There are no particular limitations on the materials of the three- dimensional object as long as it can withstand the temperatures required to transfer the image.

EXAMPLES

All of the examples were printed using the DuPont™ Artistri™ 2020 digital textile printing system, and the commercial disperse dye inks sold by DuPont for this printer. The inks used were the ink set from the Dupont™ Artistri™ Ink, D700 Series - Disperse Dye Ink.

Comparative Example 1

Colored squares were printed onto a polyester fabric 730H, described as a Jersey Knit Polyester supplied by Testfabrics Inc. of West Pittstown, PA. The color of the printed squares was measured, then the colored square image on the initial polyester was transferred to another polyester fabric by pressing at 200⁰C for 2 minutes. The color was measured on a hand held X-Rite spectrophotometer using D65 illuminant, 10° standard observer, and the specular component of reflection was included. The press was a platen press, assembled for the purpose of precisely controlling temperature and pressure. The platen press was comprised of two parallel 6" square platens with embedded resistive heating elements that could be set to maintain a desired platen temperature. The platens were fixed in a mutually parallel position to a pneumatic press that could press the platens together at a desired pressure by means of adjustable air pressure. Care was taken to be sure the platens were aligned so as to apply equal pressure across the entire work piece being fused. The effective area of the platen could be reduced, as needed, by inserting a spacer (made, for example from silicone rubber) of appropriate dimensions to allow operation on smaller work pieces.

Table I shows the measured data. The press was used in at setting that lead to no significant pressure of the platens for this image transfer step.

Table I Comparative Example 1 Color Results

The K/S difference between the printed and the transfer textile shows that the colored square was much less colored when the image was transferred. For example, for black the transferred value of 4.2888 is much less than the 16.619 for the printed transfer media. The K/S is calculated at the maximum absorbance. Similar printing on polyester with different transfer temperatures and times resulted in similar poorer results.

Example 1

In a manner to Comparative Example I, cotton was printed and then transferred to a polyester textile. The results are shown in Table Il

Table Il Example 1 Color Results

The cotton entries were done on the printed transfer medium, and the poly(ester) entries are for the polyester textile after the image was transferred at 200⁰C for 2 minutes. The image on the polyester was dramatically improved by the transfer from the cotton to the polyester. Example 2

This example is identical to Example 1 except the transfer temperature was 200⁰C for 4 minutes.

Table 3: Example 2 Color Results

Example 2 shows the excellent transfer of the images at 200⁰C for 4 minutes.

Example 3

This example is identical to Example 1 except the transfer temperature was 215⁰C for 2 minutes. Table 4: Example 3 Color Results

Example 3 shows the excellent transfer of the images at 215°C for 2 minutes.

Example 4

This example is identical to Example 1 except the transfer temperature was 215° C for 4 minutes.

Table 5: Example 4 Color Results

Example 4 shows the excellent transfer of the images at 215°C for 4 minutes.

Claims

1. A transfer printing method for creating an image on an object, comprising the steps of:

(a) providing an inkjet printer that is responsive to digital data signals;

(b) loading the inkjet printer with a transfer medium to be printed;

2. The method of claim 1 , wherein the printer is loaded with a disperse dye ink set comprising at least two disperse dye inkjet inks suitable for printing onto the transfer medium, one of the at least two disperse dye inkjet inks being the first disperse dye ink, and another of the at least two disperse dye inkjet inks being a second disperse dye ink containing a second disperse dye having a second activation temperature; and wherein the temperature conditions are at or above the higher of the first and second activation temperatures.

3. The method of claim 2, wherein the printer is loaded with a disperse dye ink set comprising at least three disperse dye inkjet inks suitable for printing onto the transfer medium, one of the at least three disperse dye inkjet inks being the first disperse dye ink, another of the at least three disperse dye inkjet inks being the second disperse dye ink, and another of the at least three disperse dye inkjet inks being a third disperse dye inkjet ink containing a third disperse dye having a third activation temperature; and wherein the temperature conditions are at or above the higher of the first, second and third activation temperatures.

4. The method of claim 3, wherein one of the first, second or third disperse inkjet inks is cyan in color; another of the first, second or third disperse inkjet inks is magenta in color; and another of the first, second or third disperse inkjet inks is yellow in color.

5. The method of claim 3, wherein the printer is loaded with a disperse dye ink set comprising at least four disperse dye inkjet inks suitable for printing onto the transfer medium, one of the at least four disperse dye inkjet inks being the first disperse dye ink, another of the at least four disperse dye inkjet inks being the second disperse dye ink, another of the at least four disperse dye inkjet inks being the third disperse dye ink, and another of the at least four disperse dye inkjet inks being a fourth disperse dye inkjet ink containing a fourth disperse dye having a fourth activation temperature; and wherein the temperature conditions are at or above the higher of the first, second, third and fourth activation temperatures.

6. The method of claim 5, wherein one of the first, second, third or fourth disperse inkjet inks is cyan in color; another of the first, second, third or fourth disperse inkjet inks is magenta in color; another of the first, second, third or fourth disperse inkjet inks is yellow in color, and another of the first, second, third or fourth disperse inkjet inks is black in color.

7. The method of any one of claims 1-6, wherein the temperature conditions are from about 150⁰C to about 275⁰C, for from about 0.5 to about 5 minutes.

8. The method of claim 7, wherein the temperature conditions are from about 180°C to about 220⁰C, for from about 0.75 to about 2 minutes.

9. The method of any one of claims 1-8, wherein the object is a three- dimensional object.

10. The method of any one of claims 1-9, wherein the object is a polyester object.

11. The method of any one of claims 1 -10, wherein the textile transfer medium is selected from the group consisting of a knitted or woven cotton fabric, and a knitted or woven cotton blend with one or more fibers selected from the group consisting of linen, ramie, viscose, lyocell, polyamide, polyolefin, polyacrylonitrile, aramid and elastene fibers.