WO2000044976A1

WO2000044976A1 - Sublimation dye transfer to textile materials

Info

Publication number: WO2000044976A1
Application number: PCT/US2000/001580
Authority: WO
Inventors: Paul E. Takken
Original assignee: Bula, Inc.
Priority date: 1999-01-29
Filing date: 2000-01-21
Publication date: 2000-08-03
Also published as: AU2856100A

Abstract

A method of sublimation transfer printing is disclosed. The method includes placing a transfer substrate (10) containing dye (7) adjacent to the textile material (2) that is to be printed on. The transfer substrate (10) is a dye-absorbing, gas permeable substrate containing dye (7) thereon. A vacuum is applied to the textile material (2) and the transfer substrate (10), the vacuum causing the transfer substrate (10) to be securedly held against the textile material (2). A heated gas is introduced adjacent to the transfer substrate (10) and the textile material (2), the heated gas being drawn through the transfer substrate (10) and the textile material (2) so as to cause sublimation of the dye (7) in the transfer substrate (10) and transfer dye (7) to the textile material (2).

Description

DESCRIPTION

SUBLIMATION DYE TRANSFER TO TEXTILE MATERIALS

Background Of The Invention The field of the invention relates generally to printing systems that sublime dye onto textile materials.

Sublimation printing generally involves the use of a transfer medium or sheet which contains one or more dyes. The transfer medium is then applied to the surface of the textile material that is to be printed. A combination of heat and pressure is then typically applied to the transfer sheet and textile material to cause the dye to undergo sublimation (i.e., convert from solid to gaseous form). The gaseous dye then moves from the transfer medium to the surface of the textile material where the dye adheres to the surface of the pile or nap of the fabric. Previous methods have employed heated rollers, heated transfer presses and the like which forcibly compress the transfer material onto the textile material. These methods use a combination of heat and direct pressure that is introduced to the textile material and transfer medium through a metal plate, drum, roller, or the like that is either automatically or manually applied for a period of time sufficient to turn the dyes in the transfer medium into the gaseous state. The dye vapor is then transferred from the transfer medium to the surface of the textile material where the dye adheres to the fabric.

Unfortunately, this method suffers from a number of limitations. For example, when direct pressure is applied to both the transfer material and the textile material, the pressure tends to crush and ruin the surface of the fabric of the textile material. This problem is exacerbated by the fact that pressure is applied to the fabric of the textile material for an extended period of time. The crushing of the fabric of the textile material is particularly problematic with fabrics that have surface interest such as fleece, carpet, velour, corduroy, and the like.

In addition, previous methods of sublimation transfer printing produce final products that have inadequate penetration of the dye into the fabric of the textile material. It is preferred to have the dye thoroughly penetrate deep within the pile or nap of the textile fabric. This gives the fabric of the textile material a more desirous appearance and better resists color wear. Unfortunately, prior methods of sublimation printing have failed to achieve this. The products produced by prior processes often have color that fades or flakes rather easily. When this occurs, an unsightly white area is often exposed below the surface of the textile material. Prior art sublimation printing processes have also typically used paper for the transfer medium. When using paper as the transfer medium, the dye is first printed on the paper. The paper is then dried prior to being placed adjacent to the textile material. There are many diffi- ulties, however, with the use of paper as the transfer medium. First, during the printing of the dye on the paper, it is necessary to dry the dye after each color is applied to the paper to prevent the smearing or overlap of colors. This has been accomplished by several different methods, most commonly with the use of a single-head printing machine printing one color at a time and then drying the paper between the application of additional colors. In addition, the change in paper that is necessary between colorings requires the screen to be changed. Both of these processes, however, are highly labor intensive.

Alternatively, the printing on paper can be accomplished through the use of multi-head printing machines that automatically dry the dye between screens. These printing machines, however, are very expensive. In addiion, in both the single-head and multi-head machines, these methods still suffer from the limitations inherent in printing on paper material. The main difficulty in printing on paper is that the paper often loses its shape from one color to the next due to the repetitive steps of printing and drying that occurs when printing paper with multiple colors .

Summary of the Invention

In a first separate aspect of the present invention a method of transferring dye to a textile material through a sublimation transfer process includes the step of placing a transfer substrate containing dye adjacent to the textile material, wherein the transfer substrate is a dye-absorbing, gas permeable substrate containing dye thereon. A vacuum is then applied to the textile material and the transfer substrate, the vacuum causing the transfer substrate to be securedly held against the textile material. Heated gas is then introduced adjacent to the transfer substrate and the textile material, wherein the heated gas is drawn through the transfer substrate and the textile material so as to cause sublimation of the dye in the transfer substrate and transfer of the dye to the textile material. In a second, separate aspect of the invention, the method of the first separate aspect contemplates forming a transfer substrate containing dye, the transfer substrate being a dye-absorbing, gas permeable substrate.

In a third separate aspect of the invention a method of transferring dye to a textile material through a sublimation transfer process includes the step of placing a transfer substrate containing dye thereon adjacent to the textile material, the transfer substrate being made of PELLO . A combination of heat and pressure are applied to the transfer substrate so as to cause sublimation of the dye in the transfer substrate and transfer of the dye to the textile material.

In a fourth separate aspect of the invention, an apparatus for transferring dye to a textile material through a sublimation transfer process utilizing a transfer substrate includes a first chamber for introducing a heated gas through the transfer substrate and textile material and a second chamber attached to the first chamber. A gas permeable bed is fixedly attached between the first and second chambers. A heat source introduces heated gas into the first chamber. A vacuum source pulls the heated gas of the first chamber into and through the transfer substrate and the textile material and into the second chamber.

In a fifth separate aspect of the present invention, combinations of any of the foregoing aspects are contemplated.

Accordingly, it is an object of the present invention to provide an improved sublimation transfer printing method and apparatus. Unlike existing sublimation transfer printng methods, this method does not compress or crush surface interest fabrics during the process. In addition, the method permits the dye to penetrate deep within the fabric of textile materials.

Brief Description of the Drawings

FIG. 1 is a schematic view of a sublimation transfer printing process according to the prior art.

FIG. 2(a) is a schematic representation of a textile material in a natural state before sublimation printing.

FIG. 2(b) is a schematic representation of a textile material after undergoing sublimation transfer printing according to the prior art.

FIG. 3 is a schematic illustration of the method of sublimation transfer printing according to one preferred embodiment of the present invention.

FIG. 4 is a top-view of a transfer substrate, textile material and screen mesh as the gas permeable bed.

Detailed Description of the Preferred Embodiment.

Referring now to Figure 1, a brief description of the prior art process will now be described. In the prior art process, a textile material 2 and transfer medium 6 are placed adjacent to one another prior to transfer. Typically the transfer medium 6 is made of paper and is not permeable to gases such as air. The paper 6 includes thereon previously dried dye 7 that will be sublimed onto the textile material 2. The paper 6 and textile material 2 then pass through a nip formed between a pair of rollers 8. A combination of heat and pressure is then applied to both the textile material 2 and the transfer medium 6. For example, the heated rollers 8 or a heat press (not shown) are used to heat the dye in the transfer medium 6 sufficiently and transfer the dye 7 to the textile material 2 through the use of heat and direct pressure.

Unfortunately, as shown in Figure 1, the textile material 2 that is produced can suffer from a number of limitations. First and foremost, the textile material 2 is compressed and crushed from the application of the heat roller 8, heat press, or the like. Consequently, the surface of the textile material 2, i.e., the nap or the pile 4, is flattened toward the base 3 of the textile material 2. This decreases both the appearance and feel of the nap or pile 4 of the textile material 2. In addition, during the sublimation process, the dyes 7 that are sublimed have inadequate penetration into the textile material 2. This results in an un-desirous gradient of dye 7 in which the dye 7 at the surface of the textile material 2 is heavy and progressively weakens toward the base 3 of the textile material 2.

A preferred embodiment of the invention will now be described. As best seen in Figure 3, the invention utilizes a textile material 2, a gas-permeable, dye-absorbing substrate 10, a source of hot gas 12, and a vacuum 16 are employed. The term "gas-permeable, dye-absorbing substrate" 10 is meant to indicate that (1) a gas is able to penetrate into and through the surface of the substrate 10 in sufficient quantity to permit the transfer of sublimed dye 7 vapors and (2) subliming dye 7 is able to absorb into the substrate. Preferably, the gas-permeable, dye-absorbing substrate 10 is made of PELLON, a type of non-woven material used typically for fusible and sew-in interfacings to control the shape of collars, cuffs, waistbands, hems, and the like which is available from John Solomon, Inc. 515 Somerville Ave . , Somerville, MA 09143-0004, style nos. 5679, 581, 572, and 580. It has been discovered that PELLON can be used for both wet-on-dry and wet-on-wet printing. With reference to the wet-on-wet process, much of the cost associated with expensive printing machines can be avoided. The printing of the dye 7 onto the gas-permeable, dye- absorbing substrate 10 can be done by standard screen printing machines such as oval-type, rotary-^type, belt-type and the like (not shown) . In addition, the use of PELLON as the gas-permeable, dye-absorbing substrate 10 advantageously permits the gas-permeable, dye-absorbing substrate 10 to be used a plurality of times per transfer during the wet-on-wet process given PELLON' s superior absorption capabilities depending on the design needed.

As seen in Figure 3, the method of printing is accomplished by first placing the textile material 2 on a gas permeable bed 14, preferably a steel screen mesh 14. The gas permeable bed 14 or screen mesh 14 is located within a housing 20. The housing 20 preferably includes a first chamber 22 and a second chamber 26. The gas permeable bed 14 is fixedly disposed between the first chamber 22 and the second chamber 26. The screen mesh 14 contains a plurality of open spaces or holes that permit gas to readily flow through while also providing support to the textile material 2. Adjacent to the textile material 2, and opposite the screen mesh 14 is the gas-permeable, dye-absorbing substrate 10. The gas-permeable, dye-absorbing substrate 10 is shown in Figures 3 and 4 as being placed above the screen mesh 14 and the textile material 2, but other orientations are within the scope of this invention. As shown in Figure 4, the gas-permeable, dye-absorbing substrate 10 has dye 7 in various colors and or patterns contained thereon.

A heated gas 12 is introduced over the surface of the gas-permeable, dye-absorbing substrate 10 and the textile material 2. Preferably, the heated gas 12 is heated air that is at a temperature of about 200 °F or higher. Even more preferably, heated air 12 having a temperature in the range of about 375 °F to about 425 °F is introduced above the gas-permeable, dye-absorbing substrate 10 and textile material 2. The heated gas 12 is heated through any number of conventional processes known in the art. Preferably the heated gas 12 is delivered above the surface of the gas- permeable, dye-absorbing substrate 10, however, it should be appreciated that other orientations can also be used and are within the scope of the invention.

A vacuum 16 is then created below the screen mesh 14. The vacuum 16 can be created by a vacuum pump 18 or the like. The vacuum 16 is used to pull the heated gas 12 through the gas-permeable, dye-absorbing substrate 10 and the textile material 2 as shown by arrow A in Figure 3. The heated gas 12 heats the dye 7 in the gas-permeable, dye- absorbing substrate 10 at or above its sublimation temperature. In addition, the heated gas 12 acts as a dye 7 carrier that transports the sublimed dye 7 in the textile material 2.

Alternatively, the heated gas 12 may be forced through the gas permeable, dye-absorbing substrate 10 and textile material 2 by the use of a pressure producing device such as a blower (not shown) connected to the first chamber 22. In this regard, a pressure differential created between the first and second chambers 22, 24 permits the dye-laden heated gas 12 to be either pushed or pulled through the textile material 2. In contrast to the prior art method of Figure 1, the use of the heated gas 12 and the vacuum 16 can produce superior quality printed textile materials 2 without compressing or crushing the surface of the textile material 2. In addition, the sublimed dye 7 can penetrate deep within the fibers of the textile material 2. The large gradient of dye 7 on the textile material 2 between the surface and base of the textile material 2 is thus avoided. The vacuum 16 provides a strong attractive force so that the sublimed dye 7 can travel deep into the pile or nap 4 of the textile material 2 towards the base 3. The evidence of the depth of penetration of the dye 7 can often be seen from viewing the back surface of the textile material 2 after the transfer printing process is complete. In the prior art process, the back surface of the textile material 2 appears white as the dye 7 is primarily deposited on the main surface of the fabric of the textile material 2. In contrast, a textile material 2 is produced in which an observer can often see the color (s) and/or pattern (s) "bleed through" from the main surface when viewing the textile material from the back surface. This bleed through characteristic indicates that the method produces significantly greater penetration of the dye 7 into the pile or nap 4 of the textile material 2. This produces a final product with colors and/or patterns that are more aesthetically pleasing to the eye and resist color wear better than prior-art processes. Moreover, the sublimation printing process leaves intact the surface characteristics of the textile material 2. In this manner, the present method is particularly advantageous to use with surface interest textile materials like fleece, carpet, velours, velvet, velveteen, chenille, corduroy, fake fur, french terry, plush, rugs, sliver knits, terry (woven and knitted) , berber, knits, rib-knits, sweater-knits and the like. It should be understood that this list is illustrative of the types of textile materials 2 that can be used with this process, as this method can be employed on many other surface interest fabrics.

For instance, the method contemplated works particularly well on surface interest fabrics such as knited or rib-knitted material. These fabrics are often used in socks, sweaters and winter-caps. In these fabrics, there are numerous peaks and valleys across the entirety of the clothing article. In conventional sublimation transfer printing methods, dye 7 is transferred only or primarily to the peak portions of the textile material 2. An article produced by this method thus contains unsightly white lines when the article is stretched and worn (white lines appear as the underlying fabric is typically white in color) . Unlike conventional sublimation transfer printing processes, the method as contemplated herein transfers dye 7 into the valleys and the peaks of the textile material 2. In this regard, the unsightly white dye-less portions of the textile material 2 are eliminated. Textile materials 2 can be knitted with colored threading to avoid this problem, however, this method suffers from still other limitations. First, textile materials 2 produced by this method are very expensive. Secondly, the pattern or designs are necessarily rough or jagged as the resolution of the design or pattern is limited by the stitching. The present invention avoids these limitations .

With reference to Figure 3, a description of one preferred method of sublimation printing will now be described. Initially, the desired print or design is printed on the gas-permeable, dye-absorbing substrate 10 (See Figure 4). The gas-permeable, dye-absorbing substrate 10 is printed with dye 7 in any number of conventional fashions including through the use of standard printing machines such as oval-type, rotary-type, belt-type and the like (not shown) . Other printing devices can be used to create the gas permeable, dye-absorbing substrate 10, including ink jet and electrostatic printing devices. These devices can be further connected to a computer or CPU. The method can employ any number of sublimation dyes commonly known in the art. After the dye 7 is transferred to the gas-permeable, dye-absorbing substrate 10, the gas- permeable, dye-absorbing substrate 10 is ready for use.

A textile material 2 is then placed on a gas permeable bed 14 such as steel screen mesh 14. While steel screen mesh 14 is preferred, other gas permeable materials could also be employed. Also, while the steel screen mesh 14 is seen as flat in Figure 3, other geometric orientations may be used depending on the textile material. For example, a tube-shaped screen mesh 14 may be employed for transferring dye 7 onto socks . Next, the gas-permeable, dye-absorbing substrate 10 is then placed on the textile material 2, on the side of the textile material 2 that opposes the screen mesh 14. A vacuum 16 is then created on the side of the screen mesh 14 opposite the textile material 2. The vacuum 16 holds the gas-permeable, dye-absorbing substrate 10 securedly against the textile material 2. The vacuum 16 is created through the use of one or more vacuum pumps 18 or the like. A heated gas 12 is then introduced onto the surface of the textile material 2, on the side opposite where the vacuum 16 is created. The heated gas 12 is then pulled through both the gas-permeable, dye-absorbing substrate 10 and the textile material 2.

The introduction of the heated gas 12 and the vacuum 16 is held for a specified amount of time depending on the print job. Generally, the longer the vacuum 16 is held on the textile material 2, the more dye 7 is transferred. Preferably, the vacuum 16 is held for a time period of about 2 seconds to about 60 seconds.

It should be noted that the heated gas 12 may be initiated prior to the start of the vacuum 16 or vice-versa. In a similar manner, the introduction of the textile material 2 and the gas-permeable, dye-absorbing substrate 10 onto the screen mesh 14 may occur before or after the initiation of the vacuum 16 or the flow of the heated gas 12. Different orders of the steps recited herein are contemplated.

At a sufficiently hot temperature, the heated gas 12 causes the dye 7 in the gas-permeable, dye-absorbing substrate 10 to sublime into the gaseous state. The gaseous dye 7 then travels in the fluid stream created by the flow of the hot gas 12 towards the vacuum 16. The dye 7 laden fluid stream then passes into and through the textile material 2. The dye 7 contained therein then deposits or adheres to the fabric of the textile material 2. A deep penetration of the dye 7 into the nap or pile 4 of the textile material 2 is thus created. It should be noted that the above-method as shown in Figure 3 and described above, wherein a single article of textile material 2 is subject to sublimation transfer printing is not the only manner of producing printed articles using this invention. For example, one could employ the present method of sublimation transfer printing in a continuous or semi-continuous manner. Rolls or spools of textile material 2 and/or gas-permeable, dye-absorbing substrate 10 may be employed to produce larger quantities of printed material in a continuous or semi-continuous manner. Printing methods employing these processes are well known in the art can utilize the method of sublimation transfer printing method as contemplated herein.

Thus, an improved method of sublimation transfer printing is disclosed. While embodiments and applications of this invention have been shown and described, it would be apparent to those skilled in the art that many more modifications are possible without departing from the inventive concepts herein. The invention, therefore, is not to be restricted except in the spirit of the appended claims.

Claims

1. A method of transferring dye to a textile material through a sublimation transfer process comprising the steps of: a) placing a transfer substrate containing dye adjacent to one side of the textile material, said transfer substrate being a dye-absorbing, gas permeable substrate containing dye thereon; b) applying a vacuum to the other side of the textile material and the transfer substrate; and c) introducing a heated gas adjacent to the transfer substrate when on the textile material.

2. The method of claim 1, wherein the heated gas introduced adjacent to the transfer substrate and textile material is heated to a temperature at or above about 200 °F.

3. The method of claim 1, wherein the heated gas introduced adjacent to the transfer substrate and textile material is heated to a temperature in the range of about 375 °F to about 425 °F.

4. The method of claim 1, wherein the dye-absorbing, gas permeable substrate is PELLON.

5. The method of claim 1, wherein the textile material is a surface interest fabric selected from the group consisting of fleece, carpet, velours, velvet, velveteen, chenille, corduroy, fake fur, french terry, plush, rugs, sliver knits, terry (woven and knitted) , berber, knits, rib-knits, sweater-knits .

6. The method of claim 1, further including the step of drying the transfer substrate prior to placing the transfer substrate adjacent to the textile material.

7. The method of claim 1, wherein the transfer substrate is created by a wet-on-wet process.

8. The method of claim 1, wherein the introduction of the heated gas and the application of the vacuum are maintained for a time of about two to about sixty seconds.

9. The method of claim 1, wherein the heated gas is air .

10. A method of transferring dye to a textile material through a sublimation transfer process comprising the steps of: a) forming a transfer substrate containing dye; said transfer substrate being a dye-absorbing, gas permeable substrate; b) placing a transfer substrate containing dye adjacent to the textile material; c) applying a vacuum to the textile material and transfer substrate, the vacuum causing the transfer substrate to be securedly held against the textile material; and d) introducing a heated gas adjacent to the transfer substrate and the textile material, the heated gas being drawn through the transfer substrate and the textile material so as to cause sublimation of the dye in the transfer substrate and transfer of the dye to the textile material.

11. The method of claim 10, wherein the heated gas introduced adjacent to the transfer substrate and textile material is heated to a temperature in the range of about 375 °F to about 425 °F.

12. The method of claim 10, wherein the dye-absorbing gas permeable substrate is PELLON.

13. The method of claim 10, wherein the textile material is a surface interest fabric selected from the group consisting of fleece, carpet, velours, velvet, velveteen, chenille, corduroy, fake fur, french terry, plush, rugs, sliver knits, terry (woven and knitted) , berber, knits, rib-knits, sweater-knits.

14. The method of claim 10, wherein the transfer substrate is created by a wet-on-wet process.

15. The method of claim 10, wherein the introduction of the heated gas and the application of the vacuum are maintained for a time of about two to about sixty seconds.

16. The method of claim 10, wherein the heated gas is air.

17. A method of printing on a textile material through a sublimation transfer process comprising the steps of: a) forming a transfer substrate containing a transfer agent therein, said transfer substrate being a gas permeable substrate that can absorb the transfer agent; b) placing the transfer substrate adjacent to the textile material; c) applying a vacuum to the textile material and transfer substrate, the vacuum causing the transfer substrate to be securedly held against the textile material; d) introducing a heated gas adjacent to the transfer substrate and the textile material, the heated gas being drawn through the transfer substrate and the textile material so as to cause sublimation of the transfer agent in the transfer substrate, the transfer agent vapors then travelling through and adhering to the textile material.

18. The method of claim 17, wherein the heated gas introduced adjacent to the transfer substrate and textile material is heated to a temperature in the range of about 375 °F to about 425 °F.

19. The method of claim 17, wherein the dye-absorbing gas permeable substrate is PELLON.

20. The method of claim 17, wherein the textile material is a surface interest fabric selected from the group consisting of fleece, carpet, velours, velvet, velveteen, chenille, corduroy, fake fur, french terry, plush, rugs, sliver knits, terry (woven and knitted) , berber, knits, rib-knits, sweater-knits.

21. The method of claim 17, wherein the transfer substrate is created by a wet-on-wet process.

22. The method of claim 17, wherein the introduction of the heated gas and the application of the vacuum are maintained for a time of about two to about sixty seconds.

23. The method of claim 17, wherein the heated gas is air.

24. A method of transferring dye to a textile material through a sublimation transfer process comprising the steps of: a) placing a transfer substrate containing dye adjacent to the textile material, said transfer substrate being made of PELLON; and b) applying a combination of heat and pressure to the transfer substrate and textile material so . as to cause sublimation of the dye in the transfer substrate and transfer of the dye to the textile material.

25. An apparatus for transferring dye to a textile material through a sublimation transfer process using a transfer substrate comprising: a) a first chamber; b) a second chamber attached to the first chamber; c) a gas permeable bed fixedly disposed between the first chamber and the second chamber; d) a heat source in communication with the first chamber; and e) a vacuum source in communication with the second chamber.