GB1569937A

GB1569937A - Dyes and their use in transfer printing

Info

Publication number: GB1569937A
Application number: GB2254277A
Authority: GB
Original assignee: Kodak Ltd
Current assignee: Kodak Ltd
Priority date: 1978-05-25
Filing date: 1978-05-25
Publication date: 1980-06-25

Description

(54) DYES AND THEIR USE IN TRANSFER PRINTING (71) We, KODAK LIMITED, a Company registered under the laws of England, of Kodak House, Station Road, Hemel Hempstead, Hertfordshire, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to dyes and to their use in transfer printing.

British Patent Specification No. 1,418,742 (Badische Anilin - & Soda-Fabrik A.G.) relates to and claims pyrimidine compounds having the general formula D-N=N-A wherein D is the radical of a diazotizable aniline and bears at least one electron-attracting substituent, or is the radical, optionally substituted with an electron-attracting substituent, of a diazotizable aminonaphthalene, aminodiphenyl, aminoazobenzene, aminoanthraquinone or heterocyclic compound;A is a radical of one of the general formulae:

wherein Z is hydrogen or an optionally substituted aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic radical and wherein X and Y are, each independently, a heterocyclic radical, a group having formula -NZ1Z2 in which Z1 is hydrogen or an optionally substituted aliphatic, cycloaliphatic, araliphatic or armoatic radical and in which Z2 is hydrogen or an optionally substituted aliphatic radical or a group of the formula -NZ3Z4 in which Z3 is an optionally substituted aliphatic, cycloaliphatic, araliphatic or aromatic radical and in which Z4 is hydrogen or an optionally substituted aliphatic radical, provided that when neither X nor Y is a heterocyclic radical one is a group of the aforesaid formula NZ3Z4.

These compounds are said to be useful as yellow to blue disperse dyes, suitable for dyeing textile materials of acrylonitrile polymers, synthetic polyamides, cellulose esters such as secondary acetate or triacetate, and particularly synthetic linear polyesters such as polyethylene glycol terephthalate or polymers having an analogous chemical constitution.

It has now been found that a certain limited class of dyes, which is within the scope of the above general formula, provides non-photochromic dyes which are useful in the heat transfer printing of polyamides and polyester, and which are particularly useful for printing resin-treated cotton and polyester-cotton blends. Specification No. 1,418,742 does not mention these latter materials.

In accordance with the present invention, there are provided non-photochromic azo dyes having the general formula:

Wherein Rand R1 represent the same or different alkyl groups having 1 to 6 carbon atoms; R2 represents hydrogen or an alkyl group having 1 to 3 carbon atoms; and R3 represents hydrogen, an alkyl group having 1 to 3 carbon atoms, halogen, -CF3 or -CN.

Preferably, R3 is hydrogen. More preferably R and R1 are alkyl groups having 3 to 6 carbon atoms, R2 is methyl and R3 is hydrogen. In the most preferred embodiment of the present invention, Rand R, aren-butyl, R2 is methyl and R3 is hydrogen.

Photochromism (sometimes called phototropy) is a property possessed by some compounds, including a number of dyes, as a result of which they undergo reversible photoinduced colour change. The property is discussed in Synthetic Dyes (Venkataraman) Volume II, page 1217. Photochromic dyes which are taken from one light source to another, e.g.

from daylight to tungsten lighting, appear to have changed colour when they are taken back to and viewed under the original light source. This is clearly undesirable in dyes to be used on fabrics.

Some of the dyes exemplified in No. 1,418,742 are photochromic, but the dyes provided by the present invention are non-photochromic.

As already indicated, the dyes provided by the present invention are useful in the heat transfer printing of polyamides and polyester, and are particularly useful for printing resintreated cotton and polyester-cotton blends. The enormous number of dyes encompassed by Claim 1 of No. 1,418,742 are disclosed only as being useful in disperse dyeing, and many of them would be unsuitable for transfer printing.

The known techniques of transfer printing are described in an article by D. Burtonshaw, International Dyer and Textile Printer, 335-340, 1971. In the most widely used technique, which is the one in which the dyes of the present invention may be used, a dye capable of sublimation is applied to a non-textile support such as paper or other suitable medium, and the dye is transferred by the action of heat to a contiguous material.

Also in accordance with the present invention, there is provided a transfer printing sheet which comprises a non-textile support bearing a non-photochromic azo dye having the general formula I given above, wherein R, RI, R2 and R3 are as previously defined.

Preferably the dye is in a binder, for example a suitable synthetic, semi-synthetic or natural resin. Cellulose esters and ethers may be used as binders.

The non-textile support may be paper, e.g. paper of low porosity, or metal, e.g. an aluminium foil, or a plastics film. All of these supports may be attached to another support on the non-dye-bearing side.

The dye may be applied in a printing ink by the flexographic, gravure, letterpress, silk screen or lithographic process. The dye will usually be applied in an imagewise distribution.

More than one dye may be applied to the support.

Also according to the present invention, there is provided a method of transfer printing a fabric or film of a polyamide or polyester, or a fabric comprising a resin-treated cellulosic material or a resin-treated blend of a cellulosic material and a polyester, which comprises placing the dye-bearing side of a transfer printing sheet as defined above in contact with the fabric or film and subjecting the sheet and fabric or film to heat to transfer at least some of the dye from the sheet to the fabric or film.

The transfer of the dye may take place at atmospheric pressure or reduced or increased pressure, or under vacuum, and at a temperature of 180"C to 2300C. The pressure between the sheet and fabric or film may be, for example, up to 1.5 lbisc. in. Higher pressures may be used. Apparatus is commercially available for performing transfer printing.

Also according to the present invention, there is provided a fabric or film of a polyamide or polyester, or a fabric comprising a resin-treated celluosic material or a resin-treated blend of a cellulosic material and a polyester, which has been transfer printed by a method as defined above.

Also according to the present invention, there is provided a printing ink which includes a non-photochromic azo dye having the general formula I given above, wherein R, R1, R2 and R3 are as previously defined.

By "cellulosic material", we mean natural or regenerated cellulosic material, such as cotton and viscose rayon.

By "resin-treated". we mean that the material has been modified to improve the acceptance of disperse dyes. An example of such treatment is the application of a cross-linkable urea-formaldehyde or melamine-formaldehyde precondensate, followed by curing or partial curing.

The materials and methods of the present invention may be used to apply a dye or dyes to various polyesters and polyamides. which may be in the form of coatings on other substrates, e.g. metal, leather, cotton or wool. The polyesters or polyamides may be in the form of woven, knitted, bonded or laminated fabrics, or pile fabrics, e.g. carpets.

The dyes of the present invention have good sublimation in transfer printing, and give strong greenish-yellow to yellow shades when used as described above. The dyes have good fastness to light and to wet treatments.

Some examples of the preparation of dyes in accordance with the invention will now be given.

Examples 1-4 Sodium nitrite (0.72 g) was added slowly with stirring to concentrated sulphuric acid (5 ml) at below 70"C. The mixture was warmed to 700C and then cooled to below 20"C. A mixture of propionic and acetic acids (1:5 by volume, 10 ml) was added drop by drop while the temperature was kept below 20"C. The mixture was cooled to below 5"C and o-cyanoaniline (0.01 mole) was added slowly at a temperature below 5"C, followed by the addition of propionic and acetic acids (1:5) at below 10"C. The mixture was stirred for two hours at 0-5"C to complete the diazotisation.

The diazonium solution was then added to a solution of a 2,4-diaminopyrimidine coupler in ethanol or 1:5 (by volume) propionic and acetic acids. After thirty minutes, the dye was filtered off or drowned out into water prior to filtration, depending on its solubility.

The following couplers were used: Example Coupler 1 2,4-di-n-propylamino-6-methylpyrimidine 2 2,4-di-iso -butylamino- 6-methylpyrimidine 3 2,4-di-n-butylamino-6-methylpyrimidine 4 2,4-di-n-hexylamino-6-methylpyrimidine Example 5 The above procedure was repeated, using 4-chloro-2 -cyanoaniline instead of o-cyanoaniline. The coupler was 2,4-di -n-butylamino -6-methylpyrimidine.

The products of Examples 1-5 were used to prepare inks by the following procedure. A sample of each dye (0.5 g) was ball milled with ethyl cellulose (3g) and a 9:1 (by volume) mixture of ethanol and ethylene glycol (50g) for 24 hours. The resulting inks were applied to pieces of flexographic transfer printing paper (55g/sq. m) and allowed to dry. The paper was then used for transfer printing on to polyamide fabric (nylon 6.6) at 200"C for 30 seconds, and on to polyester fabric at 210 C for 30 seconds.

Greenish-yellow prints were produced, having good wash fastness and light fastness.

Samples of a 50:50 polyester, cotton woven blend fabric were impregnated with the following resin formulation to a level of 60-70% wet pick up: Hexamethylol methyl melamine (type L 5155 supplied by B.I.P. Chemicals Ltd.) 50 g/l Glyoxal Urea-Formaldehyde precondensate (type BT 333, B.I.P. Chemicals Ltd.) 60 g/l Monammonium dihydrogen phosphate 2 g/l Softener (polyethylene type) 20 g/l The wet fabric was dried at 110 C for two minutes, then pre-cured at 200"C for 30 seconds.

Pieces of transfer printing paper prepared as described above, using the dyes of Examples 1-5. were used for transfer printing on to the resin-treated polyester/cotton fabric at 210 C for 30 seconds.

Strong greenish-yellow to yellow prints were produced. The colours had good light fastness, and their fastness to wet treatments was exceptionally good.

WHAT WE CLAIM IS: 1. A non-photochromic azo dye having the general formula:

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. strong greenish-yellow to yellow shades when used as described above. The dyes have good fastness to light and to wet treatments. Some examples of the preparation of dyes in accordance with the invention will now be given. Examples 1-4 Sodium nitrite (0.72 g) was added slowly with stirring to concentrated sulphuric acid (5 ml) at below 70"C. The mixture was warmed to 700C and then cooled to below 20"C. A mixture of propionic and acetic acids (1:5 by volume, 10 ml) was added drop by drop while the temperature was kept below 20"C. The mixture was cooled to below 5"C and o-cyanoaniline (0.01 mole) was added slowly at a temperature below 5"C, followed by the addition of propionic and acetic acids (1:5) at below 10"C. The mixture was stirred for two hours at 0-5"C to complete the diazotisation. The diazonium solution was then added to a solution of a 2,4-diaminopyrimidine coupler in ethanol or 1:5 (by volume) propionic and acetic acids. After thirty minutes, the dye was filtered off or drowned out into water prior to filtration, depending on its solubility. The following couplers were used: Example Coupler

1 2,4-di-n-propylamino-6-methylpyrimidine

2 2,4-di-iso -butylamino- 6-methylpyrimidine

3 2,4-di-n-butylamino-6-methylpyrimidine

4 2,4-di-n-hexylamino-6-methylpyrimidine Example 5 The above procedure was repeated, using 4-chloro-2 -cyanoaniline instead of o-cyanoaniline. The coupler was 2,4-di -n-butylamino -6-methylpyrimidine.

WHAT WE CLAIM IS: 1. A non-photochromic azo dye having the general formula:

wherein R and R1 represent the same of different alkyl groups having 1 to 6 carbon atoms; R2 represents hydrogen or an alkyl group having l to 3 carbon atoms; and R3 represents hydrogen, an alkyl group having 1 to 3 carbon atoms, halogen, -CF3 or -CN.

2. A dye as claimed in Claim 1, wherein R3 is hydrogen.

3. A dye as claimed in claim 2, wherein r and R' are alkyl groups having 3 to 6 carbon atoms, and Rz is methyl.

4. A dye as claimed in Claim 3, wherein Rand R, aren-butyl.

5. A dye as described in any one of Examples 1,2,4 or 5 herein.

6. A transfer printing sheet which comprises a non-textile support bearing a nonphotochromic azo dye as claimed in Claim 1.

7. A sheet as claimed in Claim 6, wherein the dye is as claimed in Claim 2.

8. A sheet as claimed in Claim 6 wherein the dye is as claimed in Claim 3.

9. A sheet as claimed in Claim 6, wherein the dye is as claimed in Claim 4.

10. A sheet as claimed in Claim 6, wherein the dye is one of those described in Examples 1. 2, 4 or 5 herein.

11. A sheet as claimed in any one of Claims 6 to 10, wherein the dye is in a binder.

12. A sheet as claimed in any one of Claims 6 to it, wherein the support is paper.

13. A sheet as claimed in Claim 6 and substantially as hereinbefore described.

14. A method of transfer printing a fabric or film of a polyamide or polyester, or a fabric comprising a resin-treated cellulosic material or a resin-treated blend of a cellulosic material and a polyester, which comprises placing the dye-bearing side of a transfer printing sheet as claimed in Claim 6 in contact with the fabric or film and subjecting the sheet and fabric or film to heat to transfer at least some of the dye from the sheet to the fabric or film.

15. A method as claimed in Claim 14, wherein the sheet is as claimed in Claim 7.

16. A method as claimed in Claim 14, wherein the sheet is as claimed in Claim 8.

17. A method as claimed in Claim 14, wherein the sheet is as claimed in Claim 9,

18. A method as claimed in Claim 14, wherein the sheet is as claimed in Claim 10.

19. A method as claimed in Claim 14. wherein the sheet is as claimed in Claim 11 or 12.

20. A method as claimed in any one of Claims 14 to 19, wherein transfer is effected at a temperature of l .80 C to 230"C.

21. A method as claimed in Claim 14 substantially as hereinbefore described.

22. A fabric or film of a polyamide or polyester, or a fabric comprising a resin-treated cellulosic material or a resin-treated blend of a cellulosic material and a polyester, which has been transfer printed by a method as claimed in Claim 14.

23. A printing ink containing a non-photochromic azo dye as claimed in Claim 1.

24. A printing ink as claimed in Claim 23, wherein the dye is as claimed in Claim 2.

25. A printing ink as claimed in Claim 23, wherein the dye is as claimed in Claim 3.

26. A printing ink as claimed in Claim 23. wherein the dye is as claimed in Claim 4.

27. A printing ink as claimed in Claim 23, wherein the dye is one of those described in Examples 1,2,4 or 5 herein.

28. A printing ink as claimed in any one of Claims 23 to 27, also containing a binder.

29. A printing ink as claimed in Claim 23 and substantially as hereinbefore described.