EP0906832B1 - Image-carrying material containing organic pigment for thermal image transfer - Google Patents

Abstract

An organic pigment with a specific surface area greater than 1 m<2>/g is used in the receptive layer of a printable substrate, comprising a base and receptive layer, for thermal transfer printing onto flat porous surfaces.

Description

The invention relates to a printable Image carrier material for thermal image transfer flat porous surfaces, especially one with ink jet inks printable thermal transfer paper.

There are different procedures, individual, personal Transfer images or motifs to textiles. This Motifs are printed using various printing processes such as thermal dye diffusion transfer process (D2T2), inkjet recording method (Ink-Jet) or toner process (electrophotography) on separation or so-called transfer papers printed and then through the action of heat and pressure on the textile goods transferred, with the paper pad being peeled off.

One of these methods is in DE 26 53 654 A1 described. This is about creation durable, xerographic images Cloth. For this, a silicone-coated sheet with a the coating layer arranged thereon, on which the picture to be generated xerographically. adversely on this transfer paper with silicone coating, that in the peeling process after the image transfer Silicone residues adhere to the fibers of the textile underlay stay.

EP 0 479 882 A1 describes a method and the associated transfer paper for transferring Descriptions on a porous surface described where the paper is coated, a PE layer containing paper. The images to be transferred are printed on the paper by dry copying and then by the action of heat and pressure on the Transfer textile pad. A disadvantage of this paper is the inadequate color density of the surface transferred images.

US 5 501 902 describes a printable paper presented the first polymer layer and an inkjet printable second layer with film-forming binder, a fine-grained thermoplastic polymer and one contains ink viscosity modifiers. With Help this transfer paper through heat and Pressure transferred to the textile base Images have a high color density and that with the Polymer layer laminate imaged a very good adhesion to the textile base. Disadvantageous this transfer paper is the use of the viscosity modifier, which is usually a hydrophilic agent such as polyethylene glycol or Is polyvinyl alcohol. This remedy works positive on the binding capacity, but has because whose water solubility has a negative impact on the Wash resistance.

JP-A-08 207450 relates to an ink jet process printable image carrier material for the thermal image transfer that is to be transferred in the Layer of a particulate thermoplastic polymer, porous inorganic particles and a hydrophilic Contains binders. JP-A-63 257679 describes a printable image carrier material for image transmission, with a thermoplastic on the printed layer Resin is applied after exposure to heat and pressure the printed ink jet material is immersed in water and then the laminate from the Ink receiving layer and the resin layer separated and glued to a final support. Neither of the two Disclosures are indications of the use of a selected organic polyamide as a pigment remove.

It is therefore an object of the invention to Develop image support material with its help xerographically generated toner images, in particular, however images created by ink-jet printing processes on flat surfaces porous surfaces, especially textile pads, with high color density can be transferred and the above also have fastness to washing.

This object is achieved by a printable image carrier material for thermal image transfer to flat porous surfaces, which contains a carrier and an image receiving layer. The image-receiving layer contains an organic pigment with a specific surface area of 2 to 10 m ² / g, measured according to the BET multipoint method according to DIN 66131 with krypton, and the organic pigment is a polyamide. According to a preferred embodiment, the pigment used in the image-receiving layer has a specific surface area of 3 to 6 m ² / g. Particularly good results were achieved with a fine-grained polyamide with an average particle size of up to approximately 30 μm and a specific surface area of more than 4 m ² / g.

The amount of the organic pigment is 50 to 90 % By weight, in particular 60 to 80% by weight, based on the entire shift.

The binder used in the image-receiving layer is preferably a film-forming polymer, for example acrylate, vinyl acetate homopolymers or Copolymers, partially saponified polyvinyl acetates, polyolefins, Olefin copolymers or polyester.

The amount of binder in the receiving layer is 10 to 50% by weight, in particular 15 to 30% by weight on the entire shift.

In a special embodiment of the invention, the Contain a cationic fixing agent in the receiving layer, for example a quaternary polyammonium salt from the Group of polyvinylbenzyltrimethyl, Polydiallyldimethyl, polymethacryloxyethyldimethylhydroxyethyl, Polyhydroxypropyldimethylammoniumchloride. But also other dye fixatives Agents such as cationic polyamines, cationic Polyacrylamides or cationic polyethyleneimines can be used. The amount of dye fixative By means of up to 15% by weight, in particular 5 to 10% by weight be.

The image-receiving layer is applied from an aqueous coating solution. All common application and dosing methods can be used for this. The application weight of the image-receiving layer can be 5 to 30 g / m ² , in particular 10 to 20 g / m ² .

A plastic film or an uncoated or surface-modified, for example coated or siliconized, paper can be used as the carrier material. A highly sized neutral base paper with a basis weight of 60 to 200 g / m ² is particularly suitable. The base paper can additionally be surface-modified with a special coating in an amount up to at most 5 g / m ² , in particular 1 to 3 g / m ² . This line can contain a natural or synthetic binder such as starch, starch derivatives, gelatin, carboxycellulose, methyl cellulose, polyvinyl alcohol, polyacrylamides and a salt of higher fatty acids or silicone compounds. The paper used as carrier material has a surface smoothness of 20 to 500 Bekk · s, in particular 100 to 300 Bekk · s, on the side to be coated (front).

In a further embodiment of the invention between the support and the image-receiving layer arranged thermoplastic layer, preferably a Ethylene copolymer, an ethylene copolymer mixture or a Ionomer resin or a mixture of these polymers or Contains copolymers.

The ethylene copolymer contains in particular 10 to 35 Mol% of another monomer. The ethylene copolymer can especially an ethylene / vinyl acetate or Ethylene / (meth) acrylic acid or an ethylene / (meth) acrylic acid alkyl ester copolymer his.

The thermoplastic layer is applied to the carrier material using an extrusion coating system. The application weight of the layer can be 5 to 50 g / m ² , in particular 10 to 30 g / m ² .

The surface of the image carrier material according to the invention can be printed with any motif using various printing methods, but in particular with the aid of ink-jet printing methods, which can then be transferred to all synthetic or natural fabrics, but also to other flat objects. For this purpose, the image carrier material printed with a motif is brought into contact with a flat base. The transfer takes place by heat (130-200 ° C) and pressure (0.13 x 10 ⁴ to 50.0 x 10 ⁴ N / m ² ). The backing material is then removed from the base.

The invention is intended to be illustrated with the aid of the following examples are explained in more detail.

example 1

The front provided a neutral sized base paper having a basis weight of 80 g / m ² and with a line of starch and 10 wt.% Chromium stearate in a coating amount of 3 g / m ^2, was tested after a corona pre-treatment with an ethylene copolymer having 24 mol% of vinyl acetate in an amount of 30 g / m ² extrusion-coated and then coated with aqueous dispersions to produce receiving layers, the compositions of which are shown in the table below in the dried state. ingredients Shares,% by weight a b c d e Urethane acrylate / vinyl acetate copolymer 10 30 - 40 - acrylic latex - - 25 - 30 Polyhexamethylene dodecanamide with BET = 4.61 m ² / g 85 65 70 50 - Poly (ε-laurine lactam) with BET = approx.4.2 m ² / g - - - - 60 polydiallyldimethylammonium 5 5 5 10 10 Application weight, g / m ² 10 10 10 20 10

On the papers according to the invention, the Inkjet printer Canon 620 a test pattern in the Basic colors made of yellow, cyan, magenta and black.

The printed paper was then brought into contact with a textile underlay (100% cotton fabric) in a press in which the image was transferred by heat (180 ° C.) and pressure (34.5 × 10 ⁴ N / m ² ) the document was made. After the transfer, the paper base was peeled off.

In a further step, the printed one Textile pad at 30 ° C with conventional detergents washed and examined.

Comparative Examples

A base paper with a basis weight of 80 g / m ² was extrusion-coated in the first step with an ethylene / vinyl acetate copolymer and then coated in the second step with aqueous coating compositions, the dry compositions of which are given in the table below. ingredients Shares,% by weight V1 V2 Urethane acrylate / vinyl acetate copolymer 20 - Polyacrylate (Rhoplex®) - 20 Polyamide with BET surface area = 4.6 m ² / g - - Vestamelt® (polyamide) with BET surface area = 0.246 m ² / g 75 - high molecular weight polyethylene with BET surface = approx.0.20 m ² / g 75 Amide / epichlorohydrin copolymer 5 5 viscosity modifier polyvinyl alcohol - - Application weight, g / m2 10 30

test results

The papers produced in accordance with the examples were with Using a Canon 620 inkjet printer with a test pattern provided and regarding the "bleed" behavior examined. Under "bleed" is the merging of the Inks on the edges of color areas lying together to understand that visually with grades 1 to 10 (very good to very bad).

Then the papers were covered with a textile backing brought in contact and the image through heat and Pressure from paper to the textile backing transfer.

In the next step, the color density was measured on the printed textile base. The density measurements were made before and after a washing process with conventional detergents at 30 ° C. The measurements were carried out with the Gretag Densitometer Type 186 D for the primary colors yellow, cyan, magenta and black. An average color density was calculated from the density values for the individual colors. example Bleed note color density before washing after washing 1a 1 1.80 1.17 1b 2 1.75 1.23 1c 2 1.77 1.24 1d 2 1.70 1.22 1e 2 1.74 1.25 V1 3 1.65 1.00 V2 4 1.65 0.95

The evaluations of the bleed shown in the table show a clear improvement for the samples according to the invention compared to those samples which were produced on substrates with organic pigment with a specific surface BET <1 m ² / g. After transferring the images to a fabric support and determining the color density, the images produced with the aid of the image carrier materials according to the invention show higher color densities and, after a washing process, a lower loss of color density. Loss of color density greater than 35% after a wash is not acceptable.

Claims (9)

1. An image support material for thermal image transfer onto flat, porous surfaces comprising a support and an image-receiving layer, characterized in that the image-receiving layer contains an organic pigment with a specific surface area of 2 to 10 m²/g, determined by the BET multipoint method according to DIN 66131 with krypton and wherein the organic pigment is a polyamide.
2. An image support material according to claim 1, characterized in that the specific surface area of the pigment is 3 to 6 m²/g.
3. An image support material according to claim 1 or 2, characterized in that the amount of organic pigment is 50 to 90 weight percent based on the dry weight of the image-receiving layer.
4. An image support material according to claims 1 to 3, characterized in that the image-receiving layer contains a film-forming binder.
5. An image support material according to claims 1 to 4, characterized in that the image-receiving layer contains a cationic dye fixing agent.
6. An image support material according to claims 1 to 5, characterized in that the support is a plastic film, an uncoated or surface-modified paper.
7. An image support material according to claims 1 to 6, characterized in that the support is a paper modified with a coating consisting of a binder and a fatty acid salt or a silicon compound.
8. An image support material according to claims 1 to 7 comprising a thermoplastic layer between the support and the receiving layer.
9. An image support material according to claim 8, characterized in that the thermoplastic layer contains an ethylene copolymer or ethylene copolymer mixture.