WO1982002689A1 - Process for forming colored images on textile materials and photosensitive film for use in said process - Google Patents

Abstract

Monochromatic or polychromatic color photographic images are developed directly on textile materials such as shirts or continuous textile bands by a thermal transfer process. The textile material (15) is first presensitized by applying thereto a coating of a diazonium coupling compound, preferably by thermal transfer of the diazonium coupling compound from a first sheet of paper ( 16). A photosensitive film containing a photosensitive layer (162) comprising a light sensitive aryldiazonium compound is exposed to a positive transparent film and is then brought into contact with the presensitized textile material. The assembly is heated to cause the transfer of the light-sensitive aryldiazonium compound onto the presensitized textile material under conditions which allow the diazo coupling reaction to take place. Multicolored images are formed by applying three layers of presensitization for each of the three basic colors, red, blue, and yellow, and correspondingly exposing the photosensitive film through positive transparent films capable of effecting color separation. The photosensitive layer (162) of the photosensitive film comprises, in addition to the light-sensitive aryldiazonium compound, a heat-active pH adjusting agent and an organic binder. The process can be carried out using common photographic equipment and allows for higher quality image proofs than those obtained with the conventional transfer process.

Description

Description

Process For Forming Colored Images

On Textile Materials And Photosensitive

Film For use In Said Process

Technical Field

This invention relates to a process for forming photographic prints on textiles by a heat transfer process from a light-sensitive film which has previously been exposed to an original image to be printed, and to a novel light-sensitive film to be used in the process. More particularly, this invention relates to a process for forming monochromatic or polychromatic photographic prints on textile material by presensitizing the textile with at least one diazonium coupler compound and developing the image on the presensitized textile by transferring at least one diazonium compound from a light-sensitive paper which has been imagewise exposed through a positive transparency of the image to be printed by placing the exposed photosensitive film in contact with the presensitized textile and heating the assembly to transfer the color-forming reactants from the film to the presensitized textile under conditions which will allow the diazo coupling reaction to proceed; and to a novel light-sensitive film capable of releasing the color-forming reactants contained therein by a heat transfer process.

Discussion of the Prior Art

Several forms of heat transfer processes for printing on textiles are known. One relatively simple technique provides for transfer of a preformed decal directly onto the fabric wherein the assembly of decal on fabric is heat processed together to firmly adhere the decal to the fabric. While relatively simple, this process has the drawbacks that the selection of the image is limited to a relatively few prefabricated decals; the adhesion of the decals to the fabric is not always permanent; the decals may curl at the edges. Another process which has become widespread is the Sublistatic Process. This process is based on the transfer onto the fabric of a designer pattern which has been printed on a sheet of paper by conventional printing techniques with a special sublimable ink. During the transfer process, the ink sublimes onto the textile and transfers the image previously printed on the paper. This process is described, for example, by C. E. Vellius, British Knitting Industry, January, 1973. This process, however, has a disadvantage of requiring a preprinted design on an intermediate paper substrate, which has to be prepared in advance by conventional printing techniques. Also, the sublimating process is not particularly conducive to high resolution prints. Another technique known for printing on textile fabrics such as polo shirts, sweat shirts, and the like, is accomplished with the aid of a computer which electronically prints a camera image directly onto the fabric. However, this process also cannot provide high resolution and is generally limited to monochromatic prints.

Disclosure of the Invention

It is accordingly an object of the present invention to provide a process for forming monochromatic or polychromatic images by a heat transfer process from a photographic positive transparency onto, textile materials with considerably higher quality of the transferred image than possible with conventional transfer processes. It is a further object of the present invention to provide a transfer printing process which permits the high resolution copying of photographic prints on textile or other suitable materials using currently available photographic equipment.

A still further object of the present invention is to provide a photosensitive paper which can be exposed by conventional photographic techniques and which allows the exposed original to be printed on textiles by a heat transfer method.

Still yet another object of the invention is to provide a transfer paper which presensitizes the surface of textile material to receive and develop a photographic image of high quality transferred from a photosensitive paper which has been previously exposed to the original of the image to be reproduced by conventional photographic techniques and equipment.

These, and other objects of the invention, which will become apparent by the following description, are provided by a process for forming a colored image from a photographic positive transparency onto textile or other suitable material by

(A) applying on the textile material a presensitizing coating layer including at least one diazonium coupler compound;

(B) providing a photosensitive film formed from

(1) a film substrate having a release layer on one surface thereof, and (2) a photosensitive layer coated on the release layer wherein the photosensitive layer comprises

(a) a light sensitive aryldiazonium compound, and (b) a heat activatable pH-adjusting agent, uniformly dispersed in an organic binder;

(C) photographically exposing the photosensitive layer of the photosensitive film through a photographic positive transparency of the original to be reproduced to imagewise decompose the light-sensitive diazonium compound;

(D) bringing the exposed photosensitive layer into contact with the presensitizing coating layer; and

(E) heating the exposed photosensitive layer to allow the remaining undecomposed light-sensitive aryldiazonium compound to react with the diazonium coupler compound on the textile material to thereby form a colored image corresponding to the original on the textile material.

Preferably, the presensitizing coating layer is applied onto the textile by providing a presensitizing film comprising (1) a film substrate having a release layer on one surface thereof and (2) a presensitizing layer on the release layer wherein the presensitizing layer includes at least one diazonium coupler compound uniformly dispersed in an organic binder; bringing the presensitizing layer of the presensitizing film into contact with the textile material; heating the assembled presensitizing film and textile material to transfer the diazonium coupler compound to the textile material; and removing the presensitizing film from the textile material.

The process is also capable of forming a polychromatic image of the original on the textile material which is based upon the formation of separate images from positive transparencies capable of color separation for each of the primary colors, red, blue, and yellow. According to this embodiment of the invention, the polychromatic image on the textile material is formed by repeating steps (A) through (E) three times, wherein in the first repetition, the presensitizing coating layer includes a first diazonium coupler compound capable of forming one of the three primary colors, such as red, and exposing the photosensitive layer through a positive transparency capable of color separation for the particular color of the diazonium coupler compound, and then repeating the steps by applying a presensitizing coating layer containing a second diazonium coupler compound capable of forming one of the two remaining primary colors, such as blue, and exposing the photosensitive layer through a positive transparency capable of color separation for the second selected primary color and, thereafter, repeating the steps by applying a presensitizing coating layer containing a third diazonium coupler compound capable of forming the third primary color, such as yellow, and exposing the photosensitive layer through a positive transparency capable of color separation for the third primary color. Because of the additive effects of the primary colors, an accurate polychromatic reproduction of the original image is obtained. The process of the invention can be carried out for manually reproducing a single image and is also adapted for continuous printing.

The present invention also provides a novel photosensitive film capable of use in the heat transfer printing process. The film includes (1) a film substrate comprising (a) a paper base, and (b) a coating of a release layer on one surface of the paper base; and (2) a coating of a photosensitive layer on the release layer. The photosensitive layer includes a (a) light-sensitive aryldiazonium compound, and (b) a heat-activatable pH adjusting agent uniformly dispersed in an organic binder which softens at the temperature of the heat transfer step. Preferably, the photosensitive composition also includes one or more of a stabilizer, an antioxidant, and a non-ionic surfactant. The photosensitive film has the property that when the photosensitive layer is imagewise exposed to actinic radiation and then heated to a temperature higher than the softening temperature of the organic binder, the color-forming reactants of the photosensitive layer can be transferred to another surface for development on the other surface.

For this purpose, the present invention also provides a transfer paper for presensitizing the other surface, preferably, a textile fabric material. The presensitizing transfer paper includes a paper base which includes a release layer coated on one surface of the paper base and a heat transferable presensitizing layer coated on the release layer which includes one or more diazonium coupler compounds and a heat softenable organic binder.

Brief Description of the Drawings

Figure 1a, 1b, and 1c illustrate the sequence of presensitizing film transfer paper according to the invention with a manually operated heat transfer press;

Figure 2 schematically illustrates, in side elevation, an exposure box for exposing a photosensitive film transfer paper according to the invention to a photographic positive transparency;

Figure 3a, 3b, and 3c illustrate the sequence of steps for contacting the presensitized textile material with the exposed photosensitive film transfer paper using the manually operated heat transfer press; Figure 4 schematically illustrates a continuous process according to the invention for forming a monochromatic colored image on a textile web;

Figure 5 schematically illustrates a continuous process, similar to figure 4, for forming a polychromatic colored image on a textile web.

Best Mode For Carrying Out The Invention

The high resolution heat transfer printing process of the invention is made possible by the provision of a photosensitive film which permits the aryldiazonium compound to be accurately transferred from the exposed photosensitive film to the presensitized textile material along with a heat-activatable pH-adjusting agent such that transfer and development of the colored image take place simultaneously to faithfully reproduce the original image. The photosensitive film includes a film substrate and a photosensitive layer.

The film substrate includes a release layer on at least one surface thereof. The function of the release layer is to permit transfer of the photosensitive layer upon application of sufficient heat to the photosensitive film. The film substrate is preferably paper such as bleached kraft paper which has been coated with an appropriate releasing agent. Suitable materials for the release agent include, for example, polyethylene, silicone polymers and metal soaps. Polyethylene and the silicone polymers are the preferred materials of the release layer. The mechanism by which the release layer functions is not entirely clear, but it is believed that the release layer softens upon the application of heat and, in that condition, has a lower degree of adhesion to the photosensitive layer coated thereon than between the photosensitive layer and textile material. Generally, the release layer is not itself transferred to the textile fabric, but if a small amount of the release layer is transferred, it does not interfere with the subsequent diazo coupling reaction. Furthermore, any release material so transferred will be removed upon laundering of the printed textile material. Although paper is the preferred film substrate because of its low cost and flexibility, other materials which can withstand the temperatures imposed during the heat transfer, typically in the range of from about 250° to 450ºF, and which are chemically resistant to the release layer and photosensitive layer can also be used.

Papers with suitable release layers are known and are commercially available, such as the product TRANS-EZE, a trademarked product of Kimberly-Clark Co. Papers with release layers are also used in the sublimation heat transfer processes described above.

The photosensitive layer is formed from a composition which includes an intimate mixture of a lightsensitive aryldiazonium compound of the type conventionally incorporated in diazotype materials and a thermally activatable pH-adjusting agent.

The following diazonium salts can be mentioned as representative examples of the wide variety of diazonium salts which decompose when subjected to actinic radiation and which can be used in the novel photosensitive compositions and processes of the present invention:

Representative of the class of aromatic diazo compounds that may be employed in the process of the present invention are compounds of the following formula:

wherein, X represents an anion, such as chlorozincate (ZnCl₂) and borontetrafluoride (BF₄);

R₁ and R₂ are the same or different and represent H, alkyl, alkoxy, alkylmercapto, aryl, aralkyl, halo, or carboxy;

R₃ represents aryl.

O-R₆, S-R₆ or CH₂-R₆;

R ₄ and R₅ are the same or different and represent hydrogen, alkyl, aryl, aryloxy, hydroxyalkyl, aralkyl, alkylacyl, and aroyl groups or R₄ and R₅ together. can form a 5- or 6-membered heterocyclic group, such as morpholine, pyrrolidine, and piperidine groups; and R₆ represents alkyl, aryl, aralkyl, alkaryl.

Representative of specific diazo compounds which may be suitably employed in the present invention include 1-diazo-4-diethylaminobenzene; 1-diazo-2,5-diethoxybenzoylamino-benzene 1-diazo-2,5-dibutoxybenzoylaminobenzene; 1-diazo-4-tolylmercapto-2,5-diethoxybenzene; 1-diazo-2,5-dimethoxy-1-p-tolylmercaptobenzene; 1-diazo-3-ethoxy-4-diethylaminobenzene; 1-diazo-4-(N-hydroxyethyl-N-methyl) aminobenzene; 1-diazo-4-n-proρylamino-3-n-propoxybenzene; p-diazodiphenylamine; 1-diazo-2-chloro-4-(dihydroxyethyl)aminobenzene; 1-diazo-4-dimethyl-aminobenzene; 1-diazo-4-dihydroxypropylaminobenzene; 1-diazo-3-methyl-4-dimethylaminobenzene; 1-diazo-2-carboxy-4-dimethylaminobenzene; and 1-diazo-4-diamylaminobenzene. A preferred group of aryldiazonium compounds includes 1-diazo-4-dimethylaminobenzene; 1-diazo-4-diethylaminobenzene; 4-diazo-N,N-diethylaminobenzene; 1-diazo-4-hydroxyethyl-N-ethylaminobenzene; 4-diazo-N-hydroxyethyl-N-ethylaminobenzene; 1-diazo-2,5-diethoxy-4-methoxybenzoylaminobenzene; 1-diazo-2, 5-diethoxy-4-phenylmorpholine; 1-diazo-2,5-dibutoxy-4-phenylmorpholine; and 4-diazo-2-methyl-N-phenylpyrrolidine; especially the ZnCl₂ and BF₄ salts thereof.

The light-sensitive aryldiazonium compound is present in the photosensitive layer in amounts of from about 0.02 to about 0.3 grams per square meter, preferably from about 0.1 to 0.15 g/sq.m. The other essential ingredient of the photosensitive composition from which the photosensitive layer is formed is a heat-activatable pH adjusting agent. This agent functions to shift the .pH of the transferred photosensitive layer to the alkaline range simultaneously with the transfer step. Accordingly, heat transfer and development of the azo dye color reaction product by the diazo coupling reaction occur at the same time. Furthermore, the pH adjusting agent is normally weakly acidic and thus also functions as a stabilizer against premature coupling reaction.

Suitable temperature sensitive pH-adjusting agents which can be used in the present invention include saccharine, diσyandiamide, semicarbazone, succinhydrazide, guanidine-2-benxothiazole, semicarbazide hydrochloride, thiosemicarbazide and isopropylamine and the salts, such as the alkali metal salts of these compounds. Saccharine, especially sodium, saccharine, is particularly preferred.

Upon heating to temperatures within the heat transfer temperature range, these compounds decompose into amine compounds and shift the pH from the acidic range to the alkaline range which permits the diazo coupling reaction to proceed. The amount of the pH-adjusting agent is therefore selected to be within the range which will give an alkaline environment during heat transfer. Although the amount will vary depending on the pH of the layer provided by the other ingredients present, generally, amounts in the range of from about 0.02 to 0.3 g/sq.m., preferably from about 0.1 to about 0.2 g/sq.m. can be used.

Other conventional additives and adjuvants such as acidic stabilizers to prevent premature coupling, antioxidants to prevent darkening of the phenolic residue from the dissociation of the aryldiazonium compound, metal salts and complexing agents for intensification of the azo dye image, and surfactants and wetting agents to promote transfer and spreadability of the transferred photosensitive layer over the presensitized textile. can be included in the photosensitive composition.

As examples of acidic stabilizers, mention can be made of such organic acids as citric acid, salicylic acid, sulfosalicylic acid, benzoic acid, benzene sulfonic acid, ascorbic acid, oxalic acid, succinic acid, tartaric acid, and acetic acid, and weak. inorganic acid, such as boric acid and phosphoric acid.

As examples of antioxidants, mention can be made of, for instance, thiourea, ethylurea, bisphenol A, N-hydroxyethyl-N-alkylthiourea, and the like. Examples of suitable metal salts and complexing agents include zinc chloride, stannic and stannous chloride, sodium cobalt nitride, ammonium, thiosulfate and hexamethylenetetraamine.

Suitable surfactants and wetting agents can be selected generally from among the several classes of nonionic and anionic surface active agents well known in the art, for example, Saponin, Tergitals (Union Carbide), Armacs (Armour & Co.), Igepals (American Cyanamide), Lissapols (ICI), Pluronics (Wyandotte), and the like.

A typical and preferred photosensitive composition will contain. a mixture of the following reactants and adjuvants in the following amounts:

(a) light sensitive aryldiazonium compound in an amount of 0.02 - 0.3 g/sq.m., preferably 0.1 g/sq.m.;

(b) thermally activatable pH adjusting agent, 0.02 - 0.3 g/sq.m., preferably 0.2 g/sq.m.;

(c) metal salt/complexing agent, 0.01 - 0.15 g/sq.m., preferably 0.1 g/sq.m.; (d) acidic stabilizer, 0.02 - 0.3 g/sq.m., preferably 0.2 g/sq.m.;

(e) antioxidant, 0.02 - 0.3 g/sq.m., preferably 0.1 g/sq.m.; and

(f) wetting agent/surfactant, g/sq.m., preferably 0.05 g/sq.m.

The photosensitive composition is dispersed in a state of fine dispersion, preferably, in a state of a solid emulsion, or more preferably, a solid solution in an organic binder. The selection of the organic binder is an important feature of the present invention. The organic binder should be moderately hydrophilic, but not hydroscopic such as, for example, as is the case in polyvinyl alcohol or other binders which absorb humidity; it must have a softening point within the temperature range of the heat transfer step; it must be of a nature to allow the ionic diffusion mechanism and the diazo coupling reaction to proceed sufficiently rapidly, and it should adhere to the textile material, ideally, by ionic bonding. It has been found that among all of the conventionally known organic binder materials used for diazo materials, ethyl cellulose satisfies all of these requirements and is the preferred organic binder. Methyl cellulose, carboxymethylcellulose, and hydroxyethylcellulose can also be used but are generally too hydrophilic or have too high an hydroxyl group content and are less preferred. Synthetic resin binders and natural binders, such as polyvinyl acetate, polyvinylpyrrolidone, and gelatine, can also be used. Mixtures of organic binders are also within the scope of the invention and, for example, up to about 20%, preferably up to about 10% of ethylcellulose can be replaced by another binder compatible therewith. (The organic binder and the other ingredients of the photosensitive composition are coated on the release coating layer of the paper film substrate from a solvent solution, in the dark or in a yellow light, using conventional methods, such as Meyer rod or reverse roll. Solvents such as aliphatic alcohols, e g., methanol, ethanol, etc., and ketones, e.g., acetone, methylethyl ketone, etc., can be used. Mixtures of ethanol and acetone at weight ratios of from about 1:4 to about 4:1, preferably, 1:2 to 3:1, are especially preferred. The amounts of the aryldiazonium compound, pH shifting compound, acidic stabilizer and antioxidant in the coating solution will each range from about 20 to 100 g, preferably from about 50 to 80 g/liter, these amounts providing the concentrations in the dry photosensitive layer described above. The amount of the organic binder will be selected to provide a thickness of the photosensitive layer on the order of from about 5 up to about 10 microns. In the process of the invention, the textile material on which the color image is to be printed is initially activated by a diazonium coupler compound or by a mixture of diazonium coupler compounds. The selection of the coupler compound or mixture of coupler compounds determines the color of the printed image.

Representative examples of diazonium coupler compounds which can be used in the present invention include any of the usual couplers well known in the art, such as, for example, phloroglucinol; 1,3,5-trihydroxy-2-methylbenzene; 1,5-dihydroxy-2-methylbenzene, o-hydroxydiphenyl; 1-hydroxynaphthalene; cyanacetanilide; 4-(acetoacetamido) benzene sulfonamide; resorcinol monoacetate; 1-acetylamino-2-naphthol-5-sulfonic acid; p-methyl-N-phenylpyrazolone; 3-methylpyrazolone; 2,5-xylenol; thiobarbituric acid; 3,5-dihydroxytoluene; 1 ,5-dihydroxynaphthalene, acetyl acetanilide; and 2,3-dihydroxynaphthalene. A list of other suitable couplers may be found in the article by Van de Griten, Photographic Journal, volume 92B (1952). A preferred group of coupler compounds includes, 2,3-dihydroxynaphthalene; β-resorcylic acid monoethanolamide; β-oxynaphthoic acid monoethanolamide; 2-hydroxy-3-naphthoic acid diethanolamide; 3-resorcylic acid ethanolamide; sodium-1-hydroxynaphthalene-4-sulfonate; 2-hydroxy-3-naphthoic acid of 2'hydroxy N-ethyl amide; 2-hydroxy napthoic acid 3-morpholino propylamide; 3-hydroxy naphthalene 2-carboxylic acid morpholine propylamide; 2,4,2',4' tetrahydroxy diphenylsulfide. For hand or manual operations of the process to reproduce a single photographic image on a single piece of textile material, e.g., a polo shirt or sweat shirt or jacket, such as illustrated in figures 1-3, the presensitizing coating layer will most preferably be applied to the textile from a presensitizing film transfer paper. This transfer paper can be formed from the same type of film substrate with release layer as described above for the photosensitive film transfer paper. Thus, a bleached Kraft paper with a polyethylene, silicone resin, or metal soap release layer can be used as the film substrate. A presensitizing layer including one or more diazonium coupler compounds uniformly dispersed in an organic binder is deposited on the release layer to form the presensitizing film transfer paper. As described for the photosensitive layer, to obtain maximum coverage over the entire area of the presensitizing coating transferred to the textile material, it is preferred that the coupler or coupler mixture is present in the presensitizing coating layer in a state of fine dispersion, most preferably as a solid emulsion or solid solution with the organic binder.

For the same reasons as discussed with the photosensitive coating layer, the preferred organic binder is ethylcellulose as the sole organic binder or with up to about 20% by weight, preferably up to about 10% by weight, of another organic binder.

The amount of the coupler of mixture of couplers in the presensitizing coating layer should be sufficient to provide from about 0.03 to about 0.4 g/sq.m. of the transfer film surface, preferably from about 0.5 to about 0.8 g/sq.m. The amount of the organic binder should be sufficient to provide a thickness of the presensitizing coating layer in the range of from about 3. up to about 10 microns.

The diazo coupler compound or mixture thereof and organic binder are coated on the release layer of the paper substrate by any conventional means, such as, Meyer rod or reverse rolls from a solvent solution. The same solvents described above for the photosensitive coating can be used for this purpose. To obtain the concentration of the coupler or coupler mixture in the dried presensitizing coating layer, the amount of the coupler should be from about 30 to about 150 grams, preferably from about 80 to about 120 grams of coupler per liter of solvent.

The presensitizing film transfer paper, as described above, can also be used for a continuous process of printing color images on a continuous web of textile material. One suitable arrangement of a continuous process is illustrated in figure 4. In this case, the presensitizing film transfer paper, as well as the photosensitive film transfer paper, are formed as continuous wound paper rolls by conventional paper coating techniques.

Instead of using a presensitizing film transfer paper in the continuous process, it is also within the scope of the invention to coat the diazo coupler compound or mixture directly on the textile material by, for example, spray coating, roller coating, rod coating, and the like. It is also possible to incorporate the diazo coupler compound or compounds directly in the textile material during the textile manufacturing process. The manual or hand printing process for printing a photograph on a single piece of textile material, according to the invention, is carried out by the following procedure, using a conventional manually operated heat transfer press: 1. The textile material is presensitized by placing the presensitizing film, presensitizing layer face down, on the textile material, and placing the assembly in a heat transfer press, which is put in the operative position with the temperature adjusted to exceed the softening point of the organic binder, for a time sufficient to transfer the presensitizing layer to the textile. After transfer is completed, the press is opened and the paper is removed from the textile, and will be replaced by the exposed photosensitive film. Heat transfer presses are commercially available and generally operate at a fixed temperature of about 350°F. At this temperature, transfer of the presensitizing layer is completed in about 30 seconds when ethyl cellulose is used as the organic binder. For other binders and for other operating temperatures, the heat transfer time can be easily determined by routine experimentation.

2. The photosensitive layer of the photosensitive film is exposed to actinic radiation, usually light in the ultraviolet wave length range, through a positive transparency of the photograph to be reproduced. Generally, exposure times from about 20 to about 50 seconds are sufficient to decompose the light sensitive aryldiazonium compound. Exposure equipment for this purpose is readily commercially available. Of course the order of steps 1 and 2 can be reversed or these steps can be carried out at the same time.

3. The exposed photosensitive film replaces the removed presensitizing film transfer paper in contact with the presensitized textile material (the exposed photosensitive layer will be facing and in intimate contact with the presensitizing coating transferred to the textile material) and the heat transfer press is again put in the operative position, at the same temperature for a period of time which is sufficient to complete the heat transfer of the photosensitive layer and development of the color image formed by the diazo coupling reaction between the diazonium coupler compound or compounds and the light-sensitive aryl diazonium compound. For most of the aryldiazonium compounds, transfer and development is completed in about 50 to 55 seconds at a temperature of 350ºF.

4. The press is opened and the photosensitive film is peeled from the textile material.

This process provides a high quality print on substantially any textile fabric. The contrast of the print, its definition and intensity, as well as the washability of the fabric without altering or degrading the print, are highly satisfactory, and substantially better than that obtainable by the sublistatic process. The process of the invention has the further advantage of allowing the reproduction of any photographic subject from a positive transparency. The manual process, according to the invention, is particularly adaptable to garment printing with a garment heat transfer press. Such presses are produced by various manufacturers, such as Lawson Co., St. Louis, Missouri, for use in the sublistatic process. The process of the present invention is also adaptable for continuous and automatic operation for printing on continuous running lengths of textile material, including by way of example only, woven, non-woven, and knitted fabrics made from any type of natural or synthetic fibers, such as cotton, polyester, cellulose acetate, nylon, rayon, etc. Naturally, a loosely woven or knitted fabric having a high percentage of open spaces would not be expected to provide a complete reproduction of the original image in view of the many areas not available for printing. The embodiment of the invention process using a manual heating press is schematically shown in figures 1-3. In figure 1(a), the textile material 15 to be printed is placed upon the lower heating element 14 of the heating press 10. The presensitizing film transfer paper 16, including the paper base 161 and presensitizing coating layer 162, is placed on top of the textile 15 such that the textile and presensitizing coating layer are in contact with each other. In figure 1(b), the heating press is placed in the operative position by closing the upper arm 11 which articulates on a pivot 12 such that the upper heating element 13 presses upon the assembly of the textile material and presensitizing film transfer paper. In the closed operative position, the heating elements 13 and 14 are activated to a temperature of about 350ºF for about 30 seconds or such other time as determined to be necessary to effect complete transfer. In figure 1(c), the press is opened and the paper 16 is peeled from the textile fabric leaving behind a presensitized coating which contains the diazonium coupler compound or compounds.

Figure 2 shows the exposure of the photosensitive film transfer paper 17 in the exposure box 18. The exposure box includes an ultraviolet light source 19 in housing 22, exposure timer 21, diffusing glass 23, pressure plate 24, and base 25. The photosensitive film transfer paper 17 is placed in the exposure box with the paper base side 171 in contact with the pressure plate and. the photographic positive transparency 26 is placed on top of the photosensitive layer 172 of the photosensitive film transfer paper. After exposure, for the time set by the exposure timer 11, the exposed photosensitive film transfer paper is placed on top of the presensitizing coating layer transferred onto textile fabric 15 in the heating press with the photosensitive layer in contact with the transferred presensitizing coating layer [see Fig. 1(a)]. In figure 3(b), the press is again closed into the operative position and maintained for a sufficient period of time to soften the release layer of the paper base and allow the heat transfer of the photosensitive film and development of the color image. In figure 3(c), the press is again opened and the photosensitive film transfer paper is peeled from the textile to expose the printed color image.

Figure 4 illustrates an embodiment of a continuous process for printing images from photographs on textile webs. As shown in figure 4, a textile web 30 is unwound from roll 31 and moving in the direction of the arrows, passes through a presensitizing zone A, and a development zone B, and the printed textile is wound on roll 32. In the presensitizing zone A, a first set of transfer heating rollers 34 and 35 are located respectively above and below the textile 30. A continuous web of presensitizing film transfer paper 36 is stored on roll 37 and is wound up on roll 38.

In the development zone B, a second set of transfer heating rollers 39 and 40 are located respectively above and below the textile web 30. The photosensitive film transfer paper 41 is stored on winding roll 42 and rewound on roll 43. The exposure of the photosensitive layer is accomplished with an exposure device which includes an ultraviolet tube 44 centered in a mask 48 located within quartz glass tube or cylinder 45. A positive transparency 46 of the pattern to be printed on the textile web is secured on the glass cylinder 45. Counter roller 47 presses the photosensitive layer of the photosensitive film transfer paper against the positive transparency 46 to insure good optical reproduction when both are rotated by the advance of the transfer paper 41.

The continuous printing process using the apparatus illustrated in figure 4 operates as follows: Textile web 30 unrolls from storage roller 31 by the positive drive of wind-up roller 32, and passes between the first set of transfer rollers 34 and 35 in the presensitizing zone A. The presensitizing film transfer paper also passes between roller 34 and 35 and transfers the diazo coupling compound onto the textile web. In the meanwhile, the photosensitive layer of the photosensitive film transfer paper 41 is photographically exposed through the positive transparency as the photosensitive film transfer paper moves in the direction shown by the arrows passed opening 49 in mask 48. As the exposed photosensitive layer passes between heating rollers 39 and 40, the photosensitive layer is transferred onto the presensitized textile web, whereby the final image is formed on the textile web by the diazo coupling reaction. The textile web, having printed thereon the color image corresponding to the positive transparency, is wound up on roll 32.

As is well recognized in the art, the composition of the presensitizing layer and, particularly, the diazonium coupling compound selected, determine the color of the reproduced image whereas the positive transparency determines the pattern of the image.

As is well recognized in the art, the composition of the presensitizing layer and, particularly, the diazonium coupling compound selected, determine the color of the reproduced image whereas the positive transparency determines the pattern of the image.

Where it is desired to form a polychromic image of a photograph, three positive transparencies are formed from the photographic image, each of which is adapted for color separation for the three primary colors, red, blue, and yellow. In this case, as shown in figure 5, three presensitizing zones, A', A", and A"' , each followed, respectively, by three development zones, B', B", and B"', respectively, are provided between rolls 31 and 32. In zone A', the presensitizing layer will include a coupler compound for producing one of the three primary colors, for example, red, and the positive transparency in zone B' will be correspondingly selected to reproduce the red image on the photosensitive layer of the photosensitive film transfer paper. Similarly, in zones A" and A"', the presensitizing layer will include a diazo coupler compound for the remaining two primary colors, for example, blue and yellow, respectively. Similarly, in development zones B" and B"', the positive transparency will be adapted for color separation of blue and yellow.

The techniques for indexing and registering the red, blue and yellow images are well known and are readily available to one of ordinary skill in the art.

The invention will now be described in connection with specific embodiments which are provided as illustrative examples only, and not by way of limitation.

EXAMPLE 1 : Blue Image

PAPER A (Presensitizing Film Transfer Paper)

The following solution is coated on the release coating side of "TRANS-EZE 2000" Release Paper (Kimberly-Clark) :

Acetone 23 g

Ethanol 23 g

2,3-dihydroxynaphthalene 1.93 g Ethylcellulose (5% solution in acetone-ethanol) 1.93 g and dried.

PAPER B (Photosensitive Film Transfer Paper)

The following solution is coated on the release coating, side of "TRANS-EZE 2000" Release Paper: Ethylcellulose (5% solution in acetone-ethanol) 19 g

Ethanol 20 g

Acetone 8 g

Sulfosalicylic acid 0.5 g Zinc Chloride 0.24 g

Thiourea 0.48 g

Sodium saccharine 0.48 g

4-diazo 2-methyl 1-pyrrolidine benzene ZnCl₂ 0.48 g and dried.

A blue image is printed on cotton fabric through the following steps: a) Expose paper B to an ultraviolet light (Philips TKD type 2 fluorescent tube) through a positive transparency for 50 seconds. b) Place paper A face down on the area to be printed on the fabric, and heat both at 320°F for 30 seconds in a heat transfer press. c) Open the press, peel off paper A from the fabric and replace it by the exposed paper B in the exact same position as paper A. d) Close the press again and heat at 320ºF for 60 seconds. e) Open the press, peel off paper B and remove the printed cotton textile fabric.

EXAMPLE II: Red Image

PAPER A (Presensitizing Film Transfer Paper) The following solution is coated on "TRANS-EZE 2000" Release Paper:

Acetone 23 g

Ethanol 23 g

1-phenyl 3-methyl 5-pyrazolone 2 g Ethylcellulose (5% solution in acetone-ethanol) 2 g

PAPER B (Photosensitive Film Transfer Paper)

The following solution is coated on a "TRANS-EZE 2000" Release Paper: Ethylcellulose (5% solution in acetone-ethanol 1 9 g Ethanol 20 g Acetone 8 g p-toluene sulfonic acid 0 . 5 g Zinc chloride 0 .24 g

Thiourea 0 .48 g

Sodium saccharine 0 . 48 g 2,5-diethoxy-4-morpholino benzene BF₄ 0.48 g A red image is printed on polyester fabric following the same steps as indicated in Example I. EXAMPLE III: Yellow Image

FILM SUBSTRATE On a glazed, bleached Kraft paper 100 g/m², a 20% dispersion of SILASTIC S-2288 (Silicone resin-Dow Corning) in xylene is coated, and subsequently dried to form a film substrate for the presensitizing film and photosensitive film transfer sheets.

PAPER A (Presensitizing Film Transfer Paper)

The following solution is coated on the above substrate: Acetone 23 g

Ethanol 23 g β-Resorcylic acid mono- ethanolamide 2 g

Ethylcellulose (5% solution in acetone-ethanol) 2 g

PAPER B (Photosensitive Film Transfer Paper)

The following solution is coated on the film substrate:

Ethylcellulose (5% solution in acetone-ethanol) 1 9 g

Ethanol 20 g Acetone 8 g

Sulfosalicylic acid 0 .5 g Zinc chloride 0 . 24 g Thiourea 0 . 48 g

Sodium saccharine 0 . 48 g

1-diazo-N-hydroxyethyl-N- ethyl aminobenzene ZnCl₂ 0.48 g A yellow image is printed on fabric following the same steps as indicated in Example I. EXAMPLE IV: Black Image

FILM SUBSTRATE On a clay coated paper 100 g/m , a 30% solution of Silcolease 425. (Silicone resin-Imperial Chemical Industries) in toluene in which 4% of catalyst 59A (ICI) has been added, is coated and dried to form a film substrate for presensitizing film and photosensitive film transfer papers:

PAPER A (Presensitizing Film Transfer Paper)

The following solution is coated on the above substrate:

Acetone 23 g Ethanol 23 g

Ethylcellulose (5% solution in acetone-ethanol) 2 g Acetoacetanilide 1 g

Resorcinol 0 .5 g

2-hydroxynaphthalene-3- carboxylic acid, naphthylamide 0.5 g

PAPER B (Photosensitive Film Transfer Paper)

The following solution is coated in the film substrate described at the beginning of this example: Ethylcellulose (5% solution in acetone-ethanol) 19 g Ethanol 20 g

Acetone 8 g

Sulfosalicylic acid 0.5 g

Zinc chloride 0.24 g

Thiourea 0.48 g Sodium saccharine 0.48 g

1 -diazo-4-N,N-diethylaminobenzene borofluoride 0.48 g A black image is printed on a fabric following the same steps as indicated in Example I.

The same Examples I to IV are applicable to the coating and manufacture of rolls of transfer papers for industrial printing, as illustrated in Figs. 4 and 5.

Claims

Claims 1. A process for forming a colored image from a photographic positive onto textile material which comprises: (A) applying a presensitizing coating layer onto the textile material, said layer including at least one diazonium coupler compound;

(B) providing a photosensitive film comprising: (1) a film substrate having a release layer on one surface thereof, and

(2) a photosensitive layer on said release layer, said photosensitive layer comprising: (a) a light-sensitive aryldiazonium compound, and

(h.) a heat activatable pH adjusting agent, uniformly dispersed in an organic binder; (C) photographically exposing the photosensitive layer of the photosensitive film through a photographic positive transparency to imagewise decompose the light-sensitive diazonium compound;

(D) bringing the exposed photosensitive layer into contact with the presensitizing coating layer; and

(E) heating the exposed photosensitive layer to allow the remaining undecomposed light-sensitive aryldiazonium compound to react with the diazonium coupler compound on the textile material to thereby form a colored image on the textile material.

2. The process of Claim 1 wherein step (A) comprises:

(A1) providing a presensitizing film comprising (1) a film substrate having a release layer on one surface thereof, and

(2) a presensitizing layer on said release layer, said presensitizing layer comprising at least one diazo coupler compound uniformly dispersed in an organic binder;

(A2) bringing the presensitizing layer of the presensitizing film into contact with the textile material; (A3) heating the assembled presensitizing film and textile material to thereby transfer the diazo coupler compound to the textile material; and

(A4) removing the presensitizing film from the textile material.

3. The process of claim 2 wherein said textile material is a garment and steps (A), (D), and (E) are performed manually using a manually operated heat transfer press.

4. The process of claim 1 wherein said textile material is a running textile web and wherein said process is carried out automatically and continuously.

5. The process according to claim 1 wherein said photosensitive film comprises:

(1) a film substrate having a release layer selected from the group consisting of polysilicone resins, polyethylene resins and metal soaps on one surface thereof, and

(2) a photosensitive layer on said release layer, said photosensitive layer formed from a photosensitive composition comprising: (a) a light-sensitive diazonium compound,

(b) a heat activatable pH adjusting agent selected from the group consisting of saccharine, dicyandiamide, semicarbozone, succinhydrazide, guanidine-2-benxothiazole, semicarbazide hydrochloride, thiosemicarbazide and isopropylamine or the salts thereof, and optionally

(c) a complexing agent,

(d) an acidic stabilizer, and (e) an antioxidant, said photosensitive composition being uniformly dispersed in an organic binder which softens at the temperature of the heating step (E), and in the range of from about 250ºF to about 400ºF.

6. The process of claim 5 wherein said photosensitive composition comprises from about 0.02 to 0.3 gram per square meter of said photosensitive layer of (a), from about 0.02 to 0.3 gram per square meter of said photosensitive layer of (b), up to 0.15 gram per square meter of (c), up to 0.3 gram per square meter of (d), and up to 0.3 gram per square meter of (e), and the amount of the organic binder is sufficient to form a photosensitive layer having a thickness in the range of from about 5 up to about 10 microns.

7. The process of claim 6 wherein said organic binder comprises at least 80% by weight of the total binder of ethylcellulose.

8. The process of claim 1 wherein step (E) comprises heating the exposed. photosensitive layer to a temperature in the range of from about 250°F to about 400ºF.

9. A photosensitive film comprising:

(1) a film substrate comprising (a) a paper base, and

(b) a coating of a release layer on one surface of the paper base; and

(2) a coating of a photosensitive layer on the release layer, said photosensitive layer formed from a photosensitive composition comprising a mixture of

(a) a light-sensitive aryldiazonium compound, and

(b) a heat activatable pH adjusting agent, and, optionally,

(c) a complexing agent,

(d) a stabilizer, and

(e) an antioxidant, uniformly dispersed in an organic binder which softens at temperatures of about 250ºF to about 400°F, whereby when said photosensitive layer is imagewise exposed to actinic radiation and then heated to a temperature higher than the softening temperature of the organic binder, the color-forming reactants of the photosensitive layer can be transferred to another surface for develooment on said other surface.

10. The photosensitive film of claim 9 which comprises:

(1) a film substrate having a release layer selected from the group consisting of polysilicone resins, polyethylene resins and metal soaps on one surface thereof, and

(2) a photosensitive layer on said release layer, said photosensitive layer formed from a photosensitive composition comprising (a) a light-sensitive diazonium compound,

(b) a heat activatable pH adjusting agent selected from the group consisting of saccharine, dicyandiamide, semicarbozone, succinhydrazide, guanidine-2-benzothiazole, semicarbazide hydrochloride, thiosemicarbazide, and isopropylamine or the salts thereof.

11. The photosensitive film of claim 10 wherein said photosensitive composition comprises from about 0.02 to 0.3 gram per square meter of said photosensitive layer of (a), from about 0.02 to 0.3 gram per square meter of said photosensitive layer of (b), up to 0.15 gram per square meter of (c), up to 0.3 gram per square meter of (d), and up to 0.3 gram per square meter of (e), and the amount of the organic binder is sufficient to form a photosensitive layer having a thickness in the range of from about 5 up to about 10 microns.

12. The photosensitive film of claim 11 wherein said organic binder comprises at least 80% by weight of the total binder of ethylcellulose.

13. The photosensitive composition of claim 12 wherein said photosensitive composition further comprises a wetting agent.

14. The process of claim 1 for forming a polychromatic image on textile material by repeating steps (A) through (E) three times, once for each of the three primary colors: red, blue, and yellow; which comprises in the first repetition of steps (A) through (E) applying a first presensitizing coating layer including a first diazonium coupler compound capable of producing one of the three primary colors and exposing a photosensitive layer through a positive color transparency capable of color separation of said one primary color; in the second repetition of steps (A) through (E), applying a second presensitizing color layer including a second diazonium coupler compound capable of producing a second of the three primary colors and exposing a photosensitive layer through a positive color transparency capable of color separation of said second primary color; and in the third repetition of steps (A) through (E), applying a third presensitizing coating layer including a third diazonium coupler compound capable of producing the third primary color and exposing a photosensitive layer through a positive color transparency capable of color separation of said third primary color.