FR2676965A1 - PAPER FOR APPLYING A COLORED DECORATION ON A SUBSTRATE. - Google Patents

Abstract

The invention relates to a flexible printable support, for use in performing a process for printing a synthetic material substrate by heat transfer of a printing of sublimable inks, with the creation of a vacuum between the flexible support and the substrate. synthetic material, characterized in that the flexible support is both energy receiver and energy transmitter. The flexible support has its face intended to receive the impression of sublimable inks which is smooth, the level of smoothness expressed in BEKK seconds being greater than 80 and has an air porosity of between 40 and 200 seconds, expressed in seconds GURLEY. Application to the decoration of plates of synthetic materials.

Description

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  PAPER FOR APPLYING COLORED DECORATION ON A SUBSTRATE

  The invention relates to a flexible printable support that can be used in particular as a flexible auxiliary support for transferring a colored decoration to a receiving substrate; this substrate may be of various nature (mineral, metallic, natural, synthetic, etc.), for example thermoplastic synthetic material The substrate may also be a

  layer of synthetic material applied in the form of varnish.

  EP-AO 014 615, filed by Essilor, discloses a method of applying a flexible support (for example paper) comprising a printing made from sublimable inks, on a spectacle frame placed in a chamber to empty It heats, while maintaining the vacuum, which has the effect that the flexible support intimately follows the shape

of the frames of the glasses.

  Patent application EP 90 108 663 7 describes a method for decorating by transfer of sublimable prints carried on a flexible support, this decoration being possible for substrates of synthetic materials including thermoplastic substrates which may have a resistance. with a heat that does not exceed 100 ° C. Such a process for applying a colored decor to a substrate according to which a support printed with sublimable ink is applied to this substrate is transferred

  the ink by heating on the back of the medium printed with infra-

  red as it heats the printed media at lower temperatures

  at 170 OC Preferably the support is blackened on its dorsal surface.

  According to this method, the printed support must be permeable to air. This porosity is necessary to allow a gap to be created between the printed support and the substrate to be decorated, thus avoiding the formation of folds of the support and eliminating gaseous inclusions between the support. printed and the

  substrate before and during the sublimation operation.

  A problem which therefore arises for such a method is to manufacture a flexible support, for example a paper, which satisfactorily receives the printing constituted by sublimable inks which must be transferred.

on the substrate.

  Another problem is to make a flexible support

  printable especially by an offset process with sublimable inks.

  Another problem that arises is to manufacture a flexible support printable in particular by a gravure printing process, with sublimable inks. A fourth problem that arises is to manufacture a flexible support printable either by an offset process, or by a heliographic process, with sublimable inks adapted to each of the processes; this to facilitate the transition from one process to another depending on the surfaces

  units and volumes of printing paper.

  A fifth problem that arises is to have a flexible support whose components do not interfere during the transfer operation, either by action on sublimable inks, or by parasitic gas emissions

during sublimation.

  Yet another problem is to have a good contact between the printed flexible support and the receiving substrate by creating a vacuum between the two surfaces by suction of air through the

printed support.

  Another problem is also to have a flexible support that is sufficiently resistant during the plating of the sheet, especially on

  aretes and corners of the contact areas.

  Another problem is to have a good contact between the flexible support and the receiving substrate by creating an electrostatic charge

  either on the support, or on the substrate, or on both.

  Another problem that arises is to have a flexible support having the property of accepting and preserving this charge without any adverse effects.

secondary.

  Another problem that arises is to manufacture a flexible support that effectively allows the sublimation of the inks and this by heating the

  support at temperatures below 170 OC.

  The invention therefore aims to provide such a flexible printable medium which

  to solve the problems mentioned above.

  For this purpose, the invention provides a printable flexible medium for use in carrying out a method of substrate printing by heat transfer of sublimable ink printing, with vacuum being produced between the flexible support and the substrate. , characterized in that the flexible support is both a power receiver and an energy transmitter. In this way, the flexible support will be a receiver of the energy supplied by infra-red radiation heating, limiting as much as possible the reflection effects which could be generating energy losses and

  heterogeneous distribution on the treated surface.

  Thus, the energy supplied by infra-red radiation heating on the back of the flexible support is retransmitted on its opposite face, namely the

  face that features sublimable ink printing.

  According to a preferred embodiment of the invention, the flexible support is such that its constituents are inert with respect to the sublimable inks used. Moreover, the flexible support according to the invention is such that its constituents do not exhibit adverse effects during the operation of

sublimation.

  Preferably, the flexible support according to the invention is such that its face intended to receive the impression is smooth, namely the level of smoothing expressed in seconds BEKK is greater than 80 The measurement of the BEKK smoothness is

performed according to ISO 5627.

  The flexible support according to the invention is furthermore such that its constituents

  allow treatment of electrostatic charges.

  The flexible support according to the invention is also characterized in that its weight expressed in gram per square meter is between about 30 and

  about 120 g / m 2, preferably between 50 and 70 g / m 2.

  The flexible support according to the invention is also characterized by the fact that its air permeability, expressed in Gurley seconds according to the ISO standard

  5636-5, is between about 40 seconds and about 200 seconds.

  Another characteristic of the flexible support according to the invention is that its mechanical resistance, expressed in burst resistance according to the Mullen test, is greater than or equal to approximately 250 k Pa. The Mullen test is defined.

by the ISO 2758 standard.

  In addition, the flexible support according to the invention is characterized in that its roughest face comprises a layer of non-conductive black pigments, deposited by heliographic printing, energy sensors, for example

  generated by infra-red rays.

  This type of printing makes it possible on the one hand to regulate the deposited layer and on the other hand to affect the air permeability of the support as little as possible. More preferably, the ink for black printing is an ink in a non-aqueous medium in order to maintain a good surface of the paper either during the subsequent printing by the sublimable inks, or on the product

  Finished An ink is preferably used in a methyl ketone medium.

  In addition, the ink for black printing should not alter the air permeability of the paper, it is preferable that the layer printed with this ink is not film-forming, that is to say that it does not completely cover the

paper surface.

  The following description, with reference to the examples annexed

  to understand how the invention can be put into practice.

convenient.

EXAMPLE 1

  A fibrous bleached cellulose dispersion comprising about one third of long softwood fibers and two thirds of short fibers of a mixture of half eucalyptus fibers and beech fibers, and refined to 50 degrees Shoeger, is made after adding 25% of precipitated calcium carbonate, for example the Hydrocarb 90 product from the OMYA company. This dispersion is introduced at the head of a Fourdrinier type Fourdrinier flat-table paper machine, and the residue is dried and dried.

  paper that is smoothed using a grille on or off the machine.

  A sheet having the following characteristics is obtained: Weight per square meter: 70 Thickness in micrometers: 75 BEKK smoothing in seconds 120 Air permeability in seconds: 40 Bursting strength in k Pa: 300 The sheet is printed by a heliographic process using suitable sublimable inks The printing is good and allows in particular to reproduce decorative effects used in the interior decoration, such as fake wood for furniture, natural stone effect, abstract and fancy decorations is carried out a transfer on a polymer plate

  thermoplastic according to the technique described in application EP-A-90 108 66 7.

  A printed plate is obtained after a transfer time of between 30

  seconds and about 1 min for a temperature close to 140 OC.

  It is found that most of the sublimable inks have been

  homogeneously transferred to the plate.

  moreover, the paper does not tear or break on the edges and

  contact angles with the plate when applying vacuum.

EXAMPLE 2

  The support of Example 1 is resumed and on the rough side a black ink is deposited by two-pass heliographic printing to obtain a color uniformity and a good overlap of the surface by selecting the frames and the depths of etched cells. The black ink is based on conductive carbon black and nitrocellulose varnish. Offset printing is printed on the other side of the sheet with sublimable inks and the transfer is carried out.

as described in Example 1.

  The transfer is carried out at the same temperatures, but in a time of about 5 to 5, obtaining deeper and more intense hues. There are two main disadvantages: Firstly, the presence of spark points during the operation of electrostatic charges of the paper, leads to the fact that the paper ignites and burns Secondly, the use of a nitrocellulose varnish or film-forming binder leads to a drop of air permeability not allowing good vacuum plating of the sheet of paper on the substrate to be printed The impression obtained on

  the substrate has fuzzy areas.

  The electrical conductivity measurements made according to ASTM D 267 with the KEYTHLEY apparatus give a surface conductivity of 1.310 ohms for an initial conductivity of the uncoated carbon black support.

3 1012 ohms.

EXAMPLE 3

  The same operations as above are carried out, but the carbon black is printed after printing the decoration with the sublimable inks.

  It is found that the paper has the same properties as that of Example 2.

EXAMPLE 4

  The same operations as in Example 2 are carried out, but the printing is carried out with an ink consisting of a non-conductive black pigment and

a binder.

  The ink is obtained by mixing red, blue and yellow organic pigments with the binder and gives a dark brown to which is added black, either organic, or based on iron oxide, or even carbon black , but in the latter case the maximum amount of carbon black

  will be at most 10% by dry weight of the total amount of the pigments.

  The printing is done so that it is not film-forming, that is,

  say that by selecting frames and engraving depths, the print does not completely cover the surface of the paper for him

keep its initial porosity.

  It can be seen that, under the same conditions of temperature and transfer time, as in Example 2, a printing result which does not contain fuzzy areas is obtained. Moreover, there is no effect of sparking and thus burning of the paper, nor a significant decrease in the air permeability of the paper thus allowing a good veneer of the sheet

on the substrate to be printed.

Claims (6)

  1 Printable flexible support, for use in carrying out a process for printing a plastic substrate by heat transfer of a sublimable ink printing, with vacuum production between the flexible support and the plastic substrate, characterized in that the flexible support is both energy receiver and energy transmitter.   2 flexible support according to claim 1, characterized in that its face intended to receive the printing of sublimable inks is smooth, the level   smoothing expressed in BEKK seconds being greater than 80.   Flexible support according to one of the preceding claims, characterized   in that it has an air porosity of between 40 and 200 seconds, expressed in GURLEY seconds.   Flexible support according to one of the preceding claims, characterized   in that it has a bursting resistance according to the MULLEN test, superior or equal to 250 k Pa.   Flexible support according to one of the preceding claims, characterized   in that its roughest face comprises a non-conductive layer of energy-absorbing black pigments, the layer being deposited by printing gravure.   Flexible support according to one of the preceding claims, characterized   in that the non-conductive layer is not film-forming.   Flexible support according to one of the preceding claims, characterized   in that the non-conductive layer comprises a mixture of organic pigments and carbon black, the maximum amount of the carbon black   being at most 10% by dry weight of the total amount of the pigments.