Image-carrying material containing organic pigment for thermal image transfer

0001The invention relates to a printable image carrier material for thermal image transfer to flat porous surfaces, in particular a printable with ink-jet inks thermal transfer paper.

0002There are several ways to transfer individual, personal pictures or motifs to textiles. These motifs are by means of various printing processes such as thermal dye diffusion transfer process (D2T2), ink jet recording method (ink jet) or toner process (electrophotography) printed on separating or so-called transfer papers and then transferred by heat and pressure further to the textile material, wherein the paper backing is removed.

0003One of these methods is described in DE 26 53 654 A1. This is the creation of durable, xerographically generated images on cloth. For this purpose, a silicone-coated web with a coating layer arranged thereon, on which the image is to be generated xerographically produced. A disadvantage of this transfer paper with silicone coating is that during the removal process, after the image transfer, silicone residues remain on the fibers of the textile underlay.

0004EP 0 479 882 A1 describes a method and the associated transfer paper for transferring representations to a porous base, the paper consisting of a coated paper containing a PE layer. The images to be transferred are printed on the paper by dry copying and then transferred by heat and pressure on the textile substrate. The disadvantage of this paper is the insufficient color density of the images transferred to the base.

0005US 5 501 902 discloses a printable paper comprising a first polymer layer and an ink jet printable second layer of film forming binder, a finely granulated thermoplastic polymer and an ink viscosity modifying agent. The transferred by means of this transfer paper by heat and pressure on the textile substrate images have a high color density and transferred to the images polymer layer laminate on a very good adhesion to the textile surface. A disadvantage of this transfer paper is the use of the viscosity modifying agent, which is usually a hydrophilic agent such as polyethylene glycol or polyvinyl alcohol. Although this agent has a positive effect on the binding capacity, it has negative effects on the washing resistance because of its water solubility.

0006It is therefore an object of the invention to develop an image carrier material, with the aid of xerographically created toner images, however generated by ink-jet printing process, images can be transferred to flat porous surfaces, in particular textile materials having a high color density in particular, and which have moreover wash fastness.

0007This object is achieved by an image carrier material comprising a support and an image-receiving layer comprising an organic pigment having a specific surface area greater than 1 m²/ g is marked. The specific surface area was measured by the BET multipoint method according to DIN 66131 with krypton.

0008In particular, a pigment having a specific surface area of ​​preferably 2 to 10, especially 3 to 6 m²/ g used in the image-receiving layer.

0009The organic pigment is preferably a thermoplastic polymer from the group of polyolefins, olefin copolymers, polyesters, cellulose esters or polyamides. Particularly good results were obtained with a finely granulated polyamide having an average particle size of up to about 30 μm and a specific surface area of ​​more than 4 m²/ g achieved.

0010The amount of the organic pigment is 50 to 90% by weight, especially 60 to 80% by weight, based on the entire layer.

0011The binder employed in the image-receiving layer is preferably a film-forming polymer, for example, acrylate, vinyl acetate homopolymers or copolymers, partially hydrolyzed polyvinyl acetates, polyolefins, olefin copolymers or polyesters.

0012The amount of the binder in the receiving layer is 10 to 50% by weight, especially 15 to 30% by weight, based on the entire layer.

0013In a particular embodiment of the invention, the receiving layer may contain a cationic fixing agent, for example a quaternary polyammonium salt from the group of polyvinylbenzyltrimethyl, polydiallyldimethyl, polymethacryloxyethyldimethylhydroxyethyl, polyhydroxypropyldimethylammonium chlorides. However, other dye-fixing agents such as cationic polyamines, cationic polyacrylamides or cationic polyethyleneimines can be used. The amount of the dye-fixing agent may be up to 15 wt. %, in particular 5 to 10 wt.% Be.

0014The image-receiving layer is applied from an aqueous coating solution. For this purpose, all customary application and metering methods can be used. The coating weight of the image-receiving layer may be 5 to 30 g / m² be, in particular 10 to 20 g / m²,

0015As a carrier material, a plastic film or an uncoated or surface-modified, for example, coated or siliconized paper can be used. Particularly suitable is a highly sized neutral base paper with a basis weight of 60 to 200 g / m², The base paper can additionally be treated with a special line in a quantity of at most 5 g / m², in particular 1 to 3 g / m² be surface-modified. This coating may contain a natural or synthetic binder such as starch, starch derivatives, gelatin, carboxycellulose, methylcellulose, polyvinyl alcohol, polyacrylamides and a salt of higher fatty acids or silicone compounds. The paper used as a carrier material has on the side to be coated (front side) a surface smoothness of 20 to 500 Bekk s, in particular 100 to 300 Bekk s on.

0016In a further embodiment of the invention, a thermoplastic layer is disposed between the support and the image-receiving layer, which preferably contains an ethylene copolymer, an ethylene copolymer mixture or an ionomer resin or a mixture of these polymers or copolymers.

0017The ethylene copolymer contains in particular 10 to 35 mol% of another monomer. The ethylene copolymer may in particular be an ethylene / vinyl acetate or an ethylene / (meth) acrylic acid or an ethylene / (meth) acrylic acid alkyl ester copolymer.

0018The thermoplastic layer is applied to the substrate by means of an extrusion coating machine. The coating weight of the layer can be 5 to 50 g / m², in particular 10 to 30 g / m² be.

0019The surface of the image carrier material according to the invention can be printed with any desired motif by means of various printing processes, but in particular with the aid of ink-jet printing processes, which can subsequently be transferred to all synthetic or natural fabrics, but also to other flat objects. For this purpose, the printed with a motif image carrier material is brought into contact with a flat surface. The transfer takes place by heat (130-200 ° C) and pressure (0.13 x 10⁴ up to 50.0 x 10⁴ N / m²) instead of. Thereafter, the carrier material is removed from the pad.

0020The invention will be explained in more detail with the aid of the following examples.

example 1

0021The front of a neutral sized base paper with a basis weight of 80 g / m² and with a line of starch and 10% by weight of chromium stearate in an amount of 3 g / m² after a corona pretreatment with an ethylene copolymer with 24 mol% vinyl acetate in an amount of 30 g / m² and subsequently coated with aqueous dispersions to form receptive layers, the compositions of which are given in the dried state in the table below. <tables id="tabl0001" num="0001"><table frame="all"><tgroup cols="6" colsep="1" rowsep="1"><colspec colnum="1" colname="col1" colwidth="26.25mm" /><colspec colnum="2" colname="col2" colwidth="26.25mm" /><colspec colnum="3" colname="col3" colwidth="26.25mm" /><colspec colnum="4" colname="col4" colwidth="26.25mm" /><colspec colnum="5" colname="col5" colwidth="26.25mm" /><colspec colnum="6" colname="col6" colwidth="26.25mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" rowsep="0" align="center">ingredients</entry><entry namest="col2" nameend="col6" align="center">Shares,% by weight</entry></row><row><entry namest="col1" nameend="col1" /><entry namest="col2" nameend="col2" align="center">a</entry><entry namest="col3" nameend="col3" align="center">b</entry><entry namest="col4" nameend="col4" align="center">c</entry><entry namest="col5" nameend="col5" align="center">d</entry><entry namest="col6" nameend="col6" align="center">e</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">Urethane acrylate / vinyl acetate copolymer</entry><entry namest="col2" nameend="col2" align="center">10</entry><entry namest="col3" nameend="col3" align="center">30</entry><entry namest="col4" nameend="col4" align="center">-</entry><entry namest="col5" nameend="col5" align="center">40</entry><entry namest="col6" nameend="col6" align="center">-</entry></row><row><entry namest="col1" nameend="col1" align="left">acrylic latex</entry><entry namest="col2" nameend="col2" align="center">-</entry><entry namest="col3" nameend="col3" align="center">-</entry><entry namest="col4" nameend="col4" align="center">25</entry><entry namest="col5" nameend="col5" align="center">-</entry><entry namest="col6" nameend="col6" align="center">30</entry></row><row><entry namest="col1" nameend="col1" align="left">Polyhexamethylenedodecanamide with BET = 4.61 m²/G</entry><entry namest="col2" nameend="col2" align="center">85</entry><entry namest="col3" nameend="col3" align="center">65</entry><entry namest="col4" nameend="col4" align="center">70</entry><entry namest="col5" nameend="col5" align="center">50</entry><entry namest="col6" nameend="col6" align="center">-</entry></row><row><entry namest="col1" nameend="col1" align="left">Poly (ε-laurolactam) with BET = ca. 4.2 m²/G</entry><entry namest="col2" nameend="col2" align="center">-</entry><entry namest="col3" nameend="col3" align="center">-</entry><entry namest="col4" nameend="col4" align="center">-</entry><entry namest="col5" nameend="col5" align="center">-</entry><entry namest="col6" nameend="col6" align="center">60</entry></row><row><entry namest="col1" nameend="col1" align="left">polydiallyldimethylammonium</entry><entry namest="col2" nameend="col2" align="center">5</entry><entry namest="col3" nameend="col3" align="center">5</entry><entry namest="col4" nameend="col4" align="center">5</entry><entry namest="col5" nameend="col5" align="center">10</entry><entry namest="col6" nameend="col6" align="center">10</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">Order weight, g / m²</entry><entry namest="col2" nameend="col2" align="center">10</entry><entry namest="col3" nameend="col3" align="center">10</entry><entry namest="col4" nameend="col4" align="center">10</entry><entry namest="col5" nameend="col5" align="center">20</entry><entry namest="col6" nameend="col6" align="center">10</entry></row></tbody></tgroup></table></tables>

0022On the papers according to the invention, a test image in the primary colors yellow, cyan, magenta and black was made using the Canon 620 ink-jet printer.

0023The printed paper was then contacted with a fabric backing (100% cotton fabric) in a press heated by heat (180 ° C) and pressure (34.5 x 10⁴ N / m²) the image was transferred to the base. After transfer, the paper carrier was peeled off.

0024In a further step, the printed textile substrate was washed and evaluated at 30 ° C. with conventional detergents.

Comparative Examples

0025A base paper with a basis weight of 80 g / m² was extrusion-coated in the first step with an ethylene / vinyl acetate copolymer and then coated in the second step with aqueous coating compositions whose compositions are given in the dried state in the table below. <tables id="tabl0002" num="0002"><table frame="all"><tgroup cols="4" colsep="1" rowsep="1"><colspec colnum="1" colname="col1" colwidth="39.37mm" /><colspec colnum="2" colname="col2" colwidth="39.37mm" /><colspec colnum="3" colname="col3" colwidth="39.37mm" /><colspec colnum="4" colname="col4" colwidth="39.37mm" /><thead valign="top"><row><entry namest="col1" nameend="col1" rowsep="0" align="center">ingredients</entry><entry namest="col2" nameend="col4" align="center">Shares,% by weight</entry></row><row><entry namest="col1" nameend="col1" /><entry namest="col2" nameend="col2" align="center">V1</entry><entry namest="col3" nameend="col3" align="center">V2</entry><entry namest="col4" nameend="col4" align="center">V3</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">Urethane acrylate / vinyl acetate copolymer</entry><entry namest="col2" nameend="col2" align="center">20</entry><entry namest="col3" nameend="col3" align="center">20</entry><entry namest="col4" nameend="col4" align="center">-</entry></row><row><entry namest="col1" nameend="col1" align="left">Polyacrylate (Rhoplex®)</entry><entry namest="col2" nameend="col2" align="center">-</entry><entry namest="col3" nameend="col3" align="center">-</entry><entry namest="col4" nameend="col4" align="center">20</entry></row><row><entry namest="col1" nameend="col1" align="left">Polyamide with BET surface area = 4.6 m²/G</entry><entry namest="col2" nameend="col2" align="center">-</entry><entry namest="col3" nameend="col3" align="center">75</entry><entry namest="col4" nameend="col4" align="center">-</entry></row><row><entry namest="col1" nameend="col1" align="left">Vestamelt® (polyamide) with BET surface area = 0.246 m²/G</entry><entry namest="col2" nameend="col2" align="center">75</entry><entry namest="col3" nameend="col3" align="center">-</entry><entry namest="col4" nameend="col4" align="center">-</entry></row><row><entry namest="col1" nameend="col1" align="left">high molecular weight polyethylene with BET surface area = ca.0.20 m²/G</entry><entry namest="col2" nameend="col2" /><entry namest="col3" nameend="col3" /><entry namest="col4" nameend="col4" align="center">75</entry></row><row><entry namest="col1" nameend="col1" align="left">Amide / epichlorohydrin copolymer</entry><entry namest="col2" nameend="col2" align="center">5</entry><entry namest="col3" nameend="col3" align="center">-</entry><entry namest="col4" nameend="col4" align="center">5</entry></row><row><entry namest="col1" nameend="col1" align="left">viscosity-modifying agent polyvinyl alcohol</entry><entry namest="col2" nameend="col2" align="center">-</entry><entry namest="col3" nameend="col3" align="center">5</entry><entry namest="col4" nameend="col4" align="center">-</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">Application weight, g / m2</entry><entry namest="col2" nameend="col2" align="center">10</entry><entry namest="col3" nameend="col3" align="center">30</entry><entry namest="col4" nameend="col4" align="center">30</entry></row></tbody></tgroup></table></tables>

test results

0026The papers prepared according to the examples were provided with a test pattern with the aid of a Canon 620 ink-jet printer and tested for the <img file="EP0906832A1_D0001.tif" />bleed "behavior under <img file="EP0906832A1_D0002.tif" />Bleed "is understood to mean the intermingling of the inks at the edges of contiguous color areas, which is assessed visually with the grades 1 to 10 (very good to very bad).

0027Subsequently, the papers were brought into contact with a textile backing and transferred the image by heat and pressure from the paper on the textile backing.

0028In the next step, the color density was measured on the printed textile underlay. Density measurements were taken before and after washing 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. From the density values ​​for the individual colors, an average color density was calculated.<tables id="tabl0003" num="0003"><table frame="all"><tgroup cols="4" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="39.37mm" /><colspec colnum="2" colname="col2" colwidth="39.37mm" /><colspec colnum="3" colname="col3" colwidth="39.37mm" /><colspec colnum="4" colname="col4" colwidth="39.37mm" /><thead valign="top"><row rowsep="1"><entry namest="col1" nameend="col1" rowsep="0" align="center">example</entry><entry namest="col2" nameend="col2" rowsep="0" align="center">Bleed note</entry><entry namest="col3" nameend="col4" align="center">color density</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" /><entry namest="col2" nameend="col2" /><entry namest="col3" nameend="col3" align="center">before washing</entry><entry namest="col4" nameend="col4" align="center">after washing</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">1a</entry><entry namest="col2" nameend="col2" align="center">1</entry><entry namest="col3" nameend="col3" align="char" char=",">1.80</entry><entry namest="col4" nameend="col4" align="char" char=",">1.17</entry></row><row><entry namest="col1" nameend="col1" align="left">1b</entry><entry namest="col2" nameend="col2" align="center">2</entry><entry namest="col3" nameend="col3" align="char" char=",">1.75</entry><entry namest="col4" nameend="col4" align="char" char=",">1.23</entry></row><row><entry namest="col1" nameend="col1" align="left">1c</entry><entry namest="col2" nameend="col2" align="center">2</entry><entry namest="col3" nameend="col3" align="char" char=",">1.77</entry><entry namest="col4" nameend="col4" align="char" char=",">1.24</entry></row><row><entry namest="col1" nameend="col1" align="left">1d</entry><entry namest="col2" nameend="col2" align="center">2</entry><entry namest="col3" nameend="col3" align="char" char=",">1.70</entry><entry namest="col4" nameend="col4" align="char" char=",">1.22</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">1e</entry><entry namest="col2" nameend="col2" align="center">2</entry><entry namest="col3" nameend="col3" align="char" char=",">1.74</entry><entry namest="col4" nameend="col4" align="char" char=",">1.25</entry></row><row><entry namest="col1" nameend="col1" align="left">V1</entry><entry namest="col2" nameend="col2" align="center">3</entry><entry namest="col3" nameend="col3" align="char" char=",">1.65</entry><entry namest="col4" nameend="col4" align="char" char=",">1.00</entry></row><row><entry namest="col1" nameend="col1" align="left">V2</entry><entry namest="col2" nameend="col2" align="center">10</entry><entry namest="col3" nameend="col3" align="char" char=",">1.54</entry><entry namest="col4" nameend="col4" align="char" char=",">0.77</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">V3</entry><entry namest="col2" nameend="col2" align="center">4</entry><entry namest="col3" nameend="col3" align="char" char=",">1.65</entry><entry namest="col4" nameend="col4" align="char" char=",">0.95</entry></row></tbody></tgroup></table></tables>

0029The evaluations of the bleed shown in the table show for the samples according to the invention a clear improvement over those samples which have been applied to substrates with organic pigment of a specific surface BET &lt;1 m²/ g were produced. After transferring the images to a fabric support and determining the color density, the images produced on the textile support using the image-transfer materials according to the invention show higher fabdensities and, after a washing process, a lower loss of color density. Color loss of more than 35% after a wash is unacceptable.