DE19954064A1 - Color donor element for thermal transfer has dye-containing areas and a transferable protective layer containing thermoplastic microspheres which expand on heating to form a matt surface on the image-receiver - Google Patents

Abstract

A color donor element for thermal transfer processes with (A) dye- and binder-containing color area(s) and (B) a transferable protective layer on a base, in which (B) contains synthetic thermoplastic microspheres with a particle size of 5-20 microns, which expand to 20-120 microns on heating during transfer to form a matt surface on the image-receiving layer. Independent claims are also included for: (i) a method for producing a protective layer on an image produced by thermal transfer by (a) heating a color donor element as above in contact with a color receiver element so as to transfer an image to an image-receiving layer on the receiver element and (b) thermally transferring a protective layer as described above onto the transferred image so as to produce a matt surface; (ii) an assembly for thermal color transfer with (a) a color donor element with a base carrying at least one dye- and binder-containing color area and another area with a transferable protective layer of about the same size as the color area, containing heat-expandable microspheres as defined above and (b) a color receiving element with an image-receiving layer on a base, located above the donor element so that the color layer is in contact with the image-receiving layer.

Description

This invention relates to a dye-donor element for thermal dye transfer and especially Ver application of a transferable protective cover layer in the ele ment for transfer to one by thermal transfer produced print (print) to a matt surface on the To generate pressure.

In past years there have been thermal transmission systems has been developed to produce prints of images based on were produced electronically by a video camera. According to a method of making such prints, a electronic image first a color separation by color film subject. The corresponding color-separated images are then converted into electrical signals. These signals are then used to produce cyan, purple and yellow signals to create. These signals are then sent to a thermal printer guided. To create the print, a teal, pure purple or yellow dye-donor element on the face brought into contact with a dye-receiving element. The two are then between a thermal print head and a print passed through the roller. A line-type thermal printer head is used to remove heat from the back of the dye Feed donor sheet. This thermal printer head has many Heating elements and is due to the blue-green, purple or yellow signals heated up. The procedure will then repeated for the other two colors. In this way will get a hard color copy that matches the original image speaks that can be viewed on a screen. Further Details of this method and a device for implementation The method can be found in US Pat. No. 4,621,271.  

Thermally generated prints are sensitive regarding a retransfer of dyes to other waiters areas and discoloration due to fingerprints. The reason for this is that dye on the Surface of the dye-receiving layer of the print is located. This dye can continue into the dye-receiving layer are introduced by thermal fusion of the printer kes with either hot rollers or a thermal head. To this In this way, the retransfer of dyes can be reduced and the sensitivity to fingerprints. Elimi However, this does not alleviate this problem. The Aufbrin A protective cover layer eliminates these problems but.

In the case of a printing process using thermal dye transmission, it is desirable that the manufactured Print in an advantageous manner with color photographic copies compare the image quality. The appearance of the finished print depends heavily on the surface texture and the Shine off. Color photographic copies are typically included Surface textures available that differ from very smooth, those with a high gloss to rough and a little matt gloss. The application of a thermal transfer However, the image on a rough surface leads to unequal Temperance problems and failures.

If a matt finish is desired on a thermal print, then so So far this has been achieved by using matt sprays or by post-print processors. Both of these solutions of the Problems, however, are costly and complicate the process ren.

US-A-3 556 934 and US-A-3 779 951 describe the Ver using microspheres in a paper and heating the pa pieres to a temperature sufficient to hold the particles in to expand the paper sheet. Finds in the patents However, there is no indication of the use of such a microcu gel in a dye-donor element for thermal color fabric transfer systems.  

US-A-5 387 573 describes a dye-donor element with a transferable protective top layer, the particles contains to reduce iridescence. In the case of this part However, there is a problem because it affects the recipient Do not roughen the surface sufficiently to reduce the gloss Reduce.

The object of the invention is to provide a color fabric donor element for thermal dye transfer pressure with which a matt finish or a finish with can produce low gloss on a receiving element.

This object is achieved according to the invention with a Dye-donor element for thermal dye transfer, which has a support on which there is at least one color Fabric layer area with an image dye in a binder tel and another area with a transferable protection layer, being the area of transferable protection layer has a size that corresponds to the area of the dye layer is approximately the same, which is characterized in that the transferable protective layer of non-expanded microspheres made of a synthetic thermoplastic polymer, which has a particle size in the unexpanded state of 5 to Have 20 microns, and which during exposure to heat during the transfer of the protective layer to an image receiving layer producing a matte surface on the image reception stretch the layer to 20 to 120 µm.

While the protective layer is being applied to the receiver gerelement, causes the heat from the linear thermal printer that the microspheres multiply their original size expand the original size. This leads to roughening the surface, resulting in a matte image or image of low shine compared to an image that is obtained on a matte surface of a photographic paper.

In the case of a preferred embodiment of the invention the dye-donor element is a multi-colored element with recurring color areas or spots of color from pure yellow purple or blue-green image dyes in a bandage  medium dispersed and an area or stain that contains the protective layer.

According to another embodiment of the invention, the Protective layer is the only layer on the donor element use in conjunction with another dye-donor element det, which contains the image dyes.

In the case of a further preferred embodiment of the Invention, the dye-donor element is a monochrome ele ment and has recurring units from two areas, the first region being a layer of an image dye, which is dispersed in a binder, and wherein the second area has the protective layer.

In the case of a further preferred embodiment of the Invention is the dye-donor element a black and white Element and has recurring units from two areas on, the first region being a layer of a mixture from image dyes, dispersed in a binder for er generation of a neutral color, and the second area has the protective layer.

According to the invention, any expandable microspheres can be used Chen are used, such as. B. those who are already in the discu US Pat. Nos. 3,556,934 and 3,779,951 be.

According to a preferred embodiment of the invention the expandable microspheres are white, spherically shaped, hollow particles with a thermoplastic shell that ver vaporizable substance of low boiling point envelops such. B. a gas that acts as a blowing agent. Be the non-expanders heated microspheres, so the thermoplastic softens The shell and the encapsulated blowing agent expands under Building pressure. This leads to an expansion of the microspheres chen.

The expandable microspheres according to the invention can be made by including Propane, butane or any other low-boiling, ver vaporizable substances in a micro envelope or microcapsule Nes thermoplastic resin such. B. a vinylidene chloride  Acrylonitrile copolymers, a methacrylic acid acryloni tril copolymers or a vinylidene chloride-acrylic acid ester Copolymers. Such microspheres are commercially available as Expancel® Microspheres 551-DU (Expancel Inc.).

The amount of microspheres to be used in the present invention is in the range of 10 to 200% by weight of the polymer used in the protective layer or the top layer. This coating thickness is 0.05 g / m ² to 1 g / m ² , preferably 0.25 g / m ² to 0.5 g / m ² .

The present invention thus enables the formation of a protective cover layer on a pressure generated by thermal transfer, by uniform application of heat me using a thermal printer head. After the transfer to thermal printing, the protective layer produces a beneficial protection against image destruction due to exposure to light, common chemicals such as. B. fats and oil from fingers, and plasticizers or Pla stifying agents from film album pages or covers, Herge provides poly (vinyl chloride). The protective layer or top layer is generally applied in a coating thickness of at least 0.05 g / m ² .

The transferable protective layer can protect the microspheres dispersed in a polymeric binder. Lots such polymeric binders have so far been for use have been described in protective layers. Examples from derar binders include those binders described in US-A- 5,332,713. In the case of a preferred off In the embodiment of the invention, poly (vinyl acetal) is used.

In practice, yellow, purple and teal color fabrics thermally from a dye-donor element on the dye-receiving material to form an image transfer. The thermal printer head is then used to the clear protective layer from another clear area or Stains on the dye-donor element or from a separate one Transfer donor element to the sheet having an image, by applying heat evenly. The clear one  Protective layer adheres to the print and is donated by the donor Carrier released in the area where heat is applied.

Any dye can be used in the dye layer of the dye-donor element of the invention before being exposed to the dye-receiving layer by the action of heat. Particularly good results have been achieved with sublimable dyes. Examples of sublimable dyes include anthraquinone dyes, e.g. B. Sumikaron Violet RS® (Sumitomo Chemical Co., Ltd.), Dianix Fast Violet 3R-FS® (Mitsubishi Chemical Industries, Ltd.), such as Kayalon Polyol Brilliant Blue N-BGM® and KST Black 146® (Nippon Kayaku Co., Ltd.); Azo dyes, such as. B. Kayalon Polyol Brilliant Blue BM®, Kayalon Polyol Dark Blue 2BM®, and KST Black KR® (Nippon Kayaku Co., Ltd.), Sumikaron Diazo Black 5G® (Sumitomo Chemical Co., Ltd.) and Miktazol Black 5GH ® (Mitsui Toatsu Chemicals, Inc.); Direct dyes such as B. Direct Dark Green B® (Mitsubishi Chemical Industries, Ltd.) and Direct Brown M® and Direct Fast Black D® (Nippon Kayaku Co., Ltd.); Acid dyes such as B. Kayanol Milling Cyanine 5R® (Nippon Kayaku Co., Ltd.); basic dyes, such as B. Sumiacryl Blue 6G® (Sumitomo Chemical Co., Ltd.) and Aizen Malachite Green® (Hodogaya Chemical Co., Ltd.); as well as the dyes of the formulas:

or any of the dyes known from US-A-4,541,830. The above dyes can be used individually or in combination with each other to form a monochrome image. The dyes can be used in a coating thickness of 0.05 to 1 g / m ² and are preferably hydrophobic.

In the dye-donor elements of the invention, one Dye separation layer used to change the density of the to improve transferred dyes. Dye separation layer Materials can consist of hydrophilic materials, such as e.g. B. those described in US-A-4,716,144.

The dye layers and the protective layer of the paint Fabric donor element can be applied to the support by coating are applied or thereon after a printing process, e.g. B. an engraving process.

On the back of the dye-donor element according to the Invention, a sliding layer can be arranged to ver prevent the print head from sticking to the dye-donor element  ben remains. Such a sliding layer contains either a fe stes or liquid lubricant material or mixtures here of, with or without polymeric binder, or a surface active agent. Preferred lubricant materials include Oils or semi-crystalline organic solids that are under melt at half 100 ° C, e.g. B. poly (vinyl stearate), beeswax, perfluorinated alkyl ester polyethers, polycaprolactone, silicone oils, Poly (tetrafluoroethylene), carbowax, poly (ethylene glycols) or any of the materials described in US-A-4 717 711; US-A-4 717 712; US-A-4 737 485 and US-A-4 738 950. Zu include suitable polymeric binders for the sliding layer Poly (vinyl alcohol-co-butyral), poly (vinyl alcohol-co-acetal), Polystyrene, poly (vinyl acetate), cellulose acetate butyrate, cellulo sea acetate propionate, cellulose acetate and ethyl cellulose.

The amount of lubricant material used in the sliding layer largely depends on the type of lubricant material, but is generally in the range of 0.001 to 2 g / m ² . If a polymeric binder is used, the lubricant material is present in an amount of 0.05 to 50% by weight, preferably 0.5 to 40% by weight, based on the polymeric binder used.

As a carrier material for the carrier of the dye donorele Any material can be used in the invention provided that it is dimensionally stable and capable of Resist heat from the thermal print head. To such Materials include polyester, such as B. Poly (ethylene terephthalate lat); Polyamides; Polycarbonates; Glassine paper; Condenser Paper; Cellulose esters such as B. cellulose acetate; Fluoropolyme re, such as B. poly (vinylidene fluoride) or poly (tetrafluoroethy len-co-hexafluoropropylene); Polyethers such as B. Polyoxymethy len; Polyacetals; Polyolefins, e.g. B. polystyrene, polyethylene len, polypropylene or methylpentene polymers; Polyimides, such as e.g. B. polyimidamides and polyetherimides. The carrier points completely generally has a thickness of 2 to 30 microns.

The dye-receiving element that comes with the dye-Do norelement of the invention is normally used a carrier on which there is a color image receiving layer  located. The carrier can be made of a transparent film hen, such as B. from a poly (ether sulfone), a polyimide, egg Nem cellulose esters, such as. B. cellulose acetate, a poly (vinyl alcohol-co-acetal) or a poly (ethylene terephthalate). The A carrier for the dye-receiving element can also be a reflec animal carrier such. B. in the case of one with a barite Layer of coated paper, one coated with polyethylene paper, a white polyester (polyester with a white pigment incorporated therein), an ivory paper, a condenser paper or a synthetic paper, e.g. B. type DuPont Tyvek®.

The color image-receiving layer can contain, for example, a polycarbonate, a polyurethane, a polyester, poly (vinyl chloride), poly (styrene-co-acrylonitrile), polycaprolactone or mixtures thereof. The color image-receiving layer can be in any amount suitable for the intended purpose. In general, good results have been obtained at a concentration of 1 to 5 g / m ² .

As described above, the dye-Do norelemente of the invention for producing a dye over wear pattern used. Such a process includes imagewise heating of a dye-donor element, as above described, and the transfer of a dye image to a Dye receiving element producing the dye over pattern. After the color image has been transferred, the protective layer is transferred to the color image.

The dye-donor element of the invention can be in sheet form or in the form of an endless roll or ribbon be used. Becomes an endless role or an endless one Tape used, so there can only be a dye or alternating ranges may differ union dyes, such as. B. sublimable teal nen and / or purple and / or yellow and / or black or other dyes. Such dyes are used for example, described in U.S. Patent Nos. 4,541,830; 4,698,651; 4,695,287; 4,701,439; 4,757,046; 4,743,582;  4,769,360 and 4,753,922. As a result, one, two, three- or four-color elements (or elements with one more larger number of colors) for implementing the invention ver be applied.

According to a preferred embodiment of the invention the dye-donor element has a poly (ethylene terephthalate) lat) carrier, which as a result with recurring areas of yellow, teal and purple dye and the above be written protective layer is coated, and the above Process steps are described for each color carried out to achieve a tri-color dye Transfer image with a protective layer thereon. Becomes the procedure was carried out only for a single color, then, of course, a monochrome dye transfer image receive.

The thermal printer heads used to transfer dye of the dye-donor elements of the invention are commercially available. For example, use the following thermal printer heads: Fujitsu Thermal Head FTP-040 MCS001, a TDK Thermal Head LV5416 or a Ther times head of the type Rohm Thermal Head KE 2008-F3.

A unit or assembly for thermal dye transfer according to the invention features:

• a) a dye-donor element, as described above,
• b) a dye-receiving element as described above,

wherein the dye receiving element in parent Be draw to the dye-donor element, so that the Dye layer of the donor element in contact with the dye image receiving layer of the receiving element arrives.

The above arrangement with these two elements can be integrated into an integral unit if a mo nochromes image to be produced. This can ge see that the two elements on their edges temporarily to Liability are brought together. After the transfer stripped the dye-receiving element, exposing the Dye transfer image.  

If a three-color image is to be produced, the generated above three times, each time heat is fed through the thermal printer head. After the first Dye has been transferred, the elements are separated the stripped. A second dye-donor element (or a other area of the donor element with a different one Color range) is then registered with the dye emp catching element in contact and the process is back get. The third color is obtained in the same way. Finally, the protective layer is put on top.

The following examples are intended to illustrate the invention chen.

example 1 Element 1 according to the invention

Protective layer donor elements were produced by coating a 6 μm thick poly (ethylene terephthalate) support with:

• 1. a adhesion-improving layer made of titanium alkoxide (DuPont Tyzor TBT®) (0.12 g / m ² ) from a mixture of n-propyl acetate and n-butyl alcohol as solvent and
• 2. a sliding layer containing polydimethylsiloxane with terminal aminopropyldimethyl groups, PS 513® (Petrarch Systems, Inc.) (0.01 g / m ² ) and a poly (vinyl acetal) binder (0.38 g / m ² ) (Sekisui KS-1), p-toluene sulfonic acid (0.0003 g / m ² ) and candelabra wax (0.02 g / m ² ), applied from diethyl ketone.

The other side of the donor element was coated with a solution of poly (vinyl acetal) (0.54 g / m ² ) (Sekisui KS-10), colloidal silica IPA-ST (Nissan Chemical Co.) (0.4 g / m ² ) and microspheres of the type Expancel® Microspheres 551-DU (Expancel Inc.) (0.22 g / m ² ) in a solvent mixture of diethyl ketone and isopropyl alcohol in a ratio of 80:20.

Element 2

This element was prepared as described for Element 1, except that it contained 0.33 g / m ² of Expancel® Microspheres 551-DU microspheres.

Element 3

This element was prepared as described for Element 1, except that it contained 0.44 g / m ² of Expancel® Microspheres 551-DU microspheres.

Comparison 1

A comparative element was prepared according to Element 1, except that it contained di vinylbenzene beads (4 µm) in an amount of 0.09 g / m ² instead of the microspheres.

Comparison 2

Another control was made as control 1 except that it contained no beads and that the amount of colloidal silica was 0.22 g / m ² .

Comparison 3

Another comparative element was prepared similarly to comparative element 1, except that it did not contain colloidal silica and that the amount of divinyl benzene beads (4 µm) was 0.22 g / m ² .

Comparison 4

Another predicate was like for comparison element 3 described manufactured, with the exception that the The particle size of the divinylbenzene beads was 15 μm.

A receiving element for thermal dye transfer was prepared by applying the following layers in the order given to a support made of a paper support laminated with OPPalyte® polypropylene:

• a) an adhesive layer of Prosil® 221 (aminopropyl-triethoxy silane) and Prosil® 2210 (amino-functional epoxysilane) (PCR, Inc.) (weight ratio 1: 1) and LiCl (0.0022 g / m ² ) in a solvent mixture of ethanol-methanol-water. The solution obtained (0.10 g / m ² ) contained approximately 1% of the silane component, 3% water and 96% 3A alcohol;
• b) a dye-receiving layer containing Makrolon® KL3-1013 (a polyether-modified bisphenol-A polycarbonate block copolymer (Bayer Ag) (1.52 g / m ² ), Lexan® 141-112 bisphenol-A polycarbonate (General Electric Co.) (1.24 g / m ² , Fluorad® FC-431, a perfluorinated surfactant based on an alkylsulfonamido alkyl ester (3M Co.) (0.011 g / m ² ), Drapex® 429 polyester plasticizer (Witco Corp.) (0.23 g / m ² ), 8 µm cross-linked divinylbenzene elastomeric beads (Eastman Kodak Co.) (0.006 g / m ² ) and diphenyl phthalate (0.46 g / m ² ) coated from dichloromethane ; and
• c) a dye-receiver top layer, applied from a solvent mixture of methylene chloride and tri chloroethylene, containing a polycarbonate random terpoly mer from bisphenol-A (50 mol%), diethylene glycol (49 mol%) and polydimethylsiloxane (1 mol%) (molecular weight 2500) block units (0.55 g / m ² ); a bisphenol A polycarbonate modified with 50 mol% diethylene glycol (molecular weight 2000) (0.11 g / m ² ); a Fluorad® FC-431 surfactant (0.022 g / m ² ); and a DC-510® (Dow Corning Corp.) surfactant (0.003 g / m ² ).

Polycarbonates used

KL3-1013, block copolymer of polyether glycol and bisphenol-A polycarbonate (Bayer Ag)

Bisphenol-A polycarbonate Lexan 141® (General Electric Company)

Comparison 5

This comparative element consisted only of the one above described receiving element.

Printing process

The transfer of the protective layer of the donor element, as described above, was carried out in a printing device, as is commercially available, using the Kodak XLS-8650 printer. This was equipped with a thermal printer head of the type TDK Thermal Head (No. LV5416) with a resolution of 300 dpi and an average resistance of 3516 Ohm. The print speed was 5 ms per line. The printer head voltage was set at 13.9 V to achieve a maximum printing energy of approximately 5 joules / cm ² at 36.4 ° C.

The protective layer was on the receiving element without printed an image dye. The surface gloss of each the pressure was measured using a Gardner Micro- Tri-gloss meter according to the ASTM standard test method for determination Specular Gloss (D 523-89). The surface Roughness measurements were carried out using the ANSI / ASME method B46.1-1985, described on page 30, section C3.1.1, in the "1985 Catalog of American National Standards" published by the American Society of Mechanical Engineers (associated with the American National Standards Institute); United engineering Center, 345 E., 47th Street, New York, N.Y. 10017. The Defini tion for Ra (average roughness) and µm-AA (arithmetic Medium) is also in the literature cited above described. The following results were obtained.  

table

The above results show that the use of Mi microsphere according to the invention to a considerable ver leads to a reduction in the gloss of the transferred protective layer and the surface roughness compared to the comparative selenium ment increased.

Claims (10)

1. dye-donor element for thermal dye transfer with a support on which there is at least one dye layer area with an image dye in a binder and another area with a transferable protective layer, the area of the transferable protective layer being one size , which is approximately the same as the area of the dye layer, characterized in that the transferable protective layer comprises non-expanded microspheres made of a synthetic thermoplastic polymer, which have a particle size in the unexpanded state of 5 to 20 µm, and which when exposed to Extend heat during transfer of the protective layer to an image-receiving layer to produce a matt surface on the image-receiving layer to 20 to 120 microns. 2. Element according to claim 1, characterized in that the microspheres are present in a coating thickness of 0.05 g / m ² to 1 g / m ² . 3. Element according to claim 1, characterized in that the microspheres from a vinylidene chloride acrylonitrile Copolymer, a methacrylic acid ester-acrylonitrile copolymer or a vinylidene chloride-acrylic acid ester copolymer are. 4. Element according to claim 1, characterized in that  the microspheres an outer shell made of a vinylidene chlo rid-acrylonitrile copolymer, a methacrylic ester acrylo nitrile copolymer or a vinylidene chloride acrylic acid ester Copolymer and a core of a low-boiling, evaporative Showable substance. 5. Element according to claim 4, characterized in that the shell of a vinylidene chloride-acrylonitrile copolymer be stands, and that the low-boiling, vaporizable substance Pro pan or butane. 6. Element according to claim 1, characterized in that the dye-donor element is a multicolor element recurring color areas of yellow, purple or blue-green image dyes dispersed in a binder, and an area with the protective layer. 7. A process for producing a protective layer on an image produced by thermal dye transfer, in which:

• a) a dye-donor element with a support on which there is a dye layer with an image dye in a binder, image-wise heated, namely in contact with a dye-receiving element, while transferring a dye image to an image-receiving layer of the dye- Receiving element to generate the dye transfer image; and
• b) in which a protective layer is thermally applied to the transferred color image, the protective layer being transferred from an element which contains unexpanded, synthetic, thermoplastic polymeric microspheres, the microspheres having a particle size in the unexpanded state of 5 to 20 μm have and which expand to 20 to 120 microns when exposed to heat during the transfer of the protective layer to the image-receiving layer, producing a matt surface on the image-receiving layer.

8. The method according to claim 7, characterized in that the microspheres are present in a coating thickness of 0.05 g / m ² to 1 g / m ² . 9. Compilation for thermal dye transfer with

• a) a dye-donor element for thermal dye transfer with a support on which there is at least one dye layer area with an image dye in a binder and another area with a transferable protective layer, the area of the portable protective layer having a size , which is approximately the same as the area of the dye layer, the over-protective protective layer having non-expanded microspheres made of a synthetic thermoplastic polymer, which have a particle size in the unexpanded state of 5 to 20 μm, and which are affected by the action of Extend heat to 20 to 120 microns during transfer of the protective layer to an image-receiving layer to form a matte surface on the image-receiving layer; and
• b) a dye-receiving element with a support on which the color image-receiving layer is located, wherein the dye-receiving element is in a superordinate position to the dye-donor element, so that the dye layer comes into contact with the color image-receiving layer.

10. Compilation according to claim 9, characterized in that the microspheres are present in a coating thickness of 0.05 g / m ² to 1 g / m ² .