GB2032469A

GB2032469A - Process for Printing Sheet-like Structures

Info

Publication number: GB2032469A
Application number: GB7931581A
Authority: GB
Original assignee: Ciba Geigy AG
Current assignee: Novartis AG
Priority date: 1978-09-14
Filing date: 1979-09-12
Publication date: 1980-05-08
Also published as: DE2936702A1

Abstract

A process for printing sheet-like structures by the heat transfer printing process is provided. A printed product, the print of which contains a pigment and a dye-receptive binder, is brought into contact with a uni-coloured or multi-coloured heat transfer printing paper, heated and separated from the heat transfer printing paper again. The heat transfer printing paper or the printed product is brought into contact with a sheet-like structure and the two are subjected to the heat transfer printing process.

Description

SPECIFICATION Process for Printing Sheet-like Structures The present invention relates to a process for printing sheet-like structures.

The present invention provides a process for printing sheet-like structures by the heat transfer printing process, which comprises bringing a printed product, the print of which contains a pigment and a binder, into contact with a uni-coloured or multi-coloured heat transfer printing paper, heating and separating the printed product from the heat transfer printing paper again, bringing a) the heat transfer printing paper, which is now provided with the negative image of the printed product, or b) the printed product, which is now provided image-wise with transfer dye, or c) the completely coated substrate provided image-wise with transfer dye, formed by bringing the printed product according to b) into contact with a substrate printed overall with a dye-receptive layer, pressing the two together and heating and separating the printed product from the substrate again, into contact with a sheet-like structure and subjecting the two to the heat transfer printing process.

The present invention also relates to the sheet-like structures printed in accordance with the above process.

The sheet-like structures to be printed according to the invention can be, for example, those consisting of paper, cardboard, wood, plastic or, preferably, textile fibres. In the case of plastic, this can be, for example, films of polyamide, polyester and the like.

Preferably, however, the process according to the invention is employed on textile sheet-like structures, such as woven fabrics, knitted fabrics or non-wovens. The fibre materials can be natural or synthetic fibres or mixtures of natural and synthetic fibres, natural fibre materials, for example made of cellulose, preferably being pre-treated with a dye-receptive compound, for example a synthetic resin, before transfer printing. Synthetic fibre materials, for example made of polyamide, polyacrylonitrile, cellulose triacetate and in particular polyester, are particularly suitable.

The sheet-like structures used according to the invention can also be printed, before or after the printing according to the invention, with further dyes by the heat transfer printing process and this additional printing can be effected over all or part of the surface or image-wise.

The heat transfer printing process is carried out in a conventional manner, for example by bringing the sheet-like structure and the charged printed product or the transfer printing paper into contact with one another at 180 to 2400C, as is described, for example, in JSDC 93 (1977), 161 - 164 or Textilveredlung 12, (1977)187-190. In this case, detailed data on the diverse variants for heat transfer printing are given in Melliand Textilberichte 56, (1975) 834-837, 56, (1975) 909 913,56, (1975) 998-1,004,and59, (1978)751-754.

The printed product, which is used as a starting material according to the invention, can be of very diverse origin. The sole condition which determines whether the printed products can be used for the process according to the invention is that the print consists at least of one pigment and one binder which is receptive for the sublimable dyes employed in the heat transfer printing process. The binders are as a rule thermoplastics such as are used in the printing industry or office copying or duplicating systems. It is obvious that printed products which are provided with a dye-receptive binder over their entire surface are not suitable for the process according to the invention.

Printed products which are particularly suitable as masters for the process according to the invention are those which have been produced using so-called office copying equipment or duplicating equipment. In particular, printed products produced by electrophotographic means on conventional paper, i.e. paper which has not been pre-treated, have proved suitable.

These printed products contain at least one pigment image-wise, the pigments in this case again being the conventional pigments used for printed products of this type, for example carbon black.

The binders, which are present image-wise on the printed product, are, for example, synthetic resins, such as homopolymers or copolymers of acrylates, methacrylates, styrene, vinyl acrylamide, ethylene, vinyl chloride, vinylidene chloride, acrylonitrile, maleic acid orfumaric acid, acrylamide, vinylpyridine or vinylpyrrolidone; silicone resins, epoxy-ester resins, alkyd resins, phenolic resins, polyester resins, for example ethylene terephthalates or ethylene sebacates, or naturally occurring resins, such as colophony, or the esters or salts thereof.

Furthermore, normal printed products, such as newsprint, can also be used as the starting printed products.

The heat transfer printing papers used according to the invention are multi-coloured or preferably uni-coloured with sublimable dyes and this is effected by simply coating the dye pastes onto a paper and then drying. Suitable dyes are described, for example, in British Patent Specifications 1 ,2 11,149, 1,344,353, 1,415,081, 1,395,188 and 1,334,114 or in German Offenlegungsschrift 2,538,070.

Depending on the master used as the original and on the procedure employed according to the invention, a positive or a negative right way round or mirror-inverted copy of the original is obtained on the sheet-like structure printed according to the invention.

Shown schematically, the process, according to the invention, according to variants a), b) and c) is, for example, as follows:

Original (positive, right S copy way round) printed product (positive, right contact with transfer paper way round) / separate a) transfer printing paper b) print/ed product (charged with dye) contact with sheet-like structure (heat I transfer / > z printing process)' sheet-like structure Jsheet-like structure (negative, right wa)r -- (positive laterally round) ~ - reversed5, c) pri ged product (after contact with transfer paper) contact with coated substrate prin ;ed, coated substrate (positive, later contact with sheet-like structure ally reversed) shee -like structure (positive, right way round) According to this diagram, positive, right way round prints are obtained only according to variant c).This circumstance, which can be troublesome, can be remedied by employing, for example, laterally reversed printed products from the start and this can be effected in a simple manner by first copying the original onto a transparent film instead of onto a paper substrate and producing a laterally reversed copy from this transparent film. Preferably, the procedure according to variant b) is employed.

The substrates which are provided overall with a dye-receptive layer are preferably printed products dyed overall, in particular in black or in some other colour. Furthermore, substrates, such as paper, coated with dye-receptive resins or binders can also be used.

Since, when the printed product is charged with transfer dye, the background (not only the copied image) also takes up some dye, it is advantageous first to make a preprint, for example on a waste fabric, for 10 to 1 5 seconds at 200 to 2200C with the printed product freshly charged with dye. The effect of this is that the background loses a large proportion of the dye. The printed product then gives an optimum result on transfer printing onto the fabric.

If the originals used are so-called colour separations for four-colour printing on films, multicoloured prints can also be produced using differently coloured transfer printing papers and by accurately positioned printing on top of one another.

In order to facilitate separation of the transfer printing paper from the printed product after warming under pressure, it has proved advantageous to treat the printed product and/or the transfer printing paper, before these are brought into contact, with a release agent, such as a silicone oil, by spraying the papers with a corresponding spray.

The transfer process between the heat transfer printing paper and the printed product is as a rule carried out at 1 50 to 2200 C, preferably by pressing together in a heatable press, for example an ironing press.

The process according to the invention enables sheet-like structures, especially textile materials, to be printed with uni-coloured or multi-coloured symbols, images or patterns in a simple and inexpensive manner, without expensive and involved printing patterns and films having to be produced.

Since, according to variant b), the printed product can always be charged again with fresh dye, it is possible to produce several prints of the same motif and also in different colours using a single printed product.

In the following examples percentages are by weight.

Example 1 A coloured reproduction of a black-and-white image or text original is produced on a polyester fabric by the following procedure: a) A copy of the original is produced on a white paper by means of an electrophotographic copying apparatus.

b) This copy is then sprayed gently with a polysiloxane solution (necessary only if the copy has motifs of large surface area). This copy is then brought into contact with a uniformly coloured heat transfer printing paper and the two are pressed together in an ironing press for 1 5 seconds at 21 00C.

The two papers are separated from one another.

c) Coloured image reproductions can now be produced from both papers on polyester fabric, by placing the papers on the fabric and pressing on the ironing press for 30 seconds at 21 00C. the heat transfer paper gives a negative but right way round image reproduction, in which the image of the original appears lighter and the background darker.

The reproduction which is obtained with the copy has a positive and laterally reversed image of the original, i.e. the motif is dark and the background lighter. If heat transfer printing papers which are produced in the following manner are used, coloured prints which are fast to light and stable to washing result on the polyester fabric.

Production of the heat transfer printing paper 1. Stock Thickener 350 g of a thickener based on a maleic anhydride/ethylene copolymer 1 50 g of a 20% polyvinyl alcohol solution of low viscosity 50 g of lacquer spirit 100 g of a 0.7% silicone oil emulsion 350 g of water 1 ,000 g of stock thickener 2.Printing Paste X g of stock thickener Ygofdye 1,000 g of printing paste The dyes are employed in the following amounts: 3 Dyes 40g/kgof(1) yellow

80 g/kg of (2) red

100 g/kg of (3) blue

60g/kgof(4) blue

200 g/kg of a mixture of the dyes of the formula (1)14.5% (2) 38% black (3) 47.5% as a 50% formulation Example 2 If the reproduction which is obtained from the copy on the fabric according to Example 1 as a mirror image of the original is to be produced as a right way round reproduction of the original, the procedure employed is as follows: a) Production of a copy of an original as in Example 1 b) Pressing the copy and a heat transfer paper together (according to Example 1).

c) Separation of the two papers.

d) Production of a copy of a black paper as the original, as in Example 1.

e) The black copy obtained according to d) and the copy which has already been pressed together with the transfer paper are pressed together on an ironing press for 30 seconds at 21 00C. By this means, the dye from the copy with the image original is transferred to the black copy (the black copy now contains the mirror image of the original).

f) The black copy is now pressed together with the polyester fabric on the ironing press for 30 seconds at 21 00C.

A coloured image of the original master results and this has very good fastness to light and washing.

The copy of the image original can be pressed together with fresh heat transfer paper as often as desired, i.e. charged with dye and used in accordance with Example 1 or with this example for the production of coloured images on polyester fabric.

Example 3 In order to produce multi-coloured reproductions, the image obtained according to Example 1 (from the heat transfer paper) can then be over-printed with paper of a different colour; alternatively, the fabric is printed in a single colour and over-printed with the heat transfer paper according to Example 1, which carries the image of the master.

Claims

1. A process for printing sheet-like structures by the heat transfer printing process, which comprises bringing a printed product, the print of which contains a pigment and a dye-receptive binder, into contact with a uni-coloured or multi-coloured heat transfer printing paper, heating and separating the printing product from the heat transfer printing paper again, bringing a) the heat transfer printing paper, which is now provided with the negative image of the printed product, or b) the printed product, which is now provided image-wise with transfer dye, or c) the completely coated substrate provided image-wise with transfer dye, formed by bringing the printed product according to b) into contact with a substrate printed overall with a dye-receptive layer, pressing the two together and heating and separating the printed product from the substrate again, into contact with a sheet-like structure and subjecting the two to the heat transfer printing process.

2. A process according to claim 1 , wherein, in process variant c), the completely coated substrate used is a black coloured printed product.

3. A process according to claim 1 or 2, wherein a sheet-like structure is printed.

4. A process according to claim 3, wherein the textile sheet-like structure printed is a woven fabric, a knitted fabric or a non-woven made of synthetic and/or natural fibre materials.

5. A process according to claim 3 or 4, wherein a fibre material containing polyester fibres is printed.

6. A process according to claim 3 or 4, wherein a cellulose-containing fibre material pre-treated with synthetic resin is printed.

7. A process according to any one of claims 1 to 6, wherein the sheet-like structure is also printed with further dyes, before or after the heat transfer printing process.

8. A process according to any preceding claim, wherein the printed product is produced on paper using an office copying or duplicating apparatus.

9. A process according to claim 8, wherein the printed product is produced by an electrophotographic process.

10. A process according to any preceding claim, wherein the heat transfer printing paper and the printed product are brought into contact with one another at 1 50 to 2200 C.

11. A process according to any preceding claim, wherein the heat transfer printing paper and/or the printed product are treated, before they are brought together, with a release agent.

12. A process according to any preceding claim, wherein the heat transfer printing process is carried out at 1 80 to 2400C.

13. A process according to any preceding claim, wherein printing is carried out by variant b).

14. A process according to claim 1, substantially as hereinbefore described, with reference to any one of the foregoing Examples.

1 5. A sheet-like structure printed according to the process of any one of claims 1 to 14.