RU2451121C1 - Thermal transfer paper for ink-jet printing with sublimation ink - Google Patents

Abstract

FIELD: textiles, paper.

SUBSTANCE: thermal transfer paper for ink-jet printing with sublimation ink consists of a base paper and a barrier coating applied on it, containing a binder and filler. The binder is taken from a group of substances, including starch, carboxymethyl cellulose, polyvinyl alcohol, gelatin or mixtures thereof. The filler contains a fine-grained powder of polymethylmethacrylate and/or a fine powder of diatomite and additional substances selected from the group including kaolin, talc, finely divided starch, silica gels, or mixtures thereof.

EFFECT: increased rate of drying, colour contrast, clarity and uniformity of sealing the image.

4 cl, 3 tbl, 3 ex

Description

The invention relates to the pulp and paper industry, in particular to the field of manufacture of special types of coated paper for digital printing, and can be used in the manufacture of thermal transfer paper for sublimation thermal transfer.

The prior art thermotransfer paper for printing by sublimation ink, consisting of a base and a barrier coating applied thereon containing a binder and a filler. As a binder, the coating contains substances selected from the group consisting of starch, carboxymethyl cellulose, polyvinyl alcohol, gelatin or mixtures thereof. As a filler, the coating contains substances selected from the group comprising kaolin, talc, finely divided starch, calcium sulfoaluminate, silica gel, or a mixture thereof (RU 2335405, 10.10.2008).

The disadvantages of this paper are:

a) insufficient clarity of the sealed image on paper due to the large dot spreading (blurring) of a dot when a single drop of ink hits the coating surface, which is especially true when printing images with large ink fills;

b) when printing images with fills from 200% or more in printing mode from 360 * 540 dpi and above, the specified paper is subject to great deformation during image printing and when the ink dries, which requires an increase in the distance between the paper and the print head. This significantly reduces the clarity of the image.

The closest in technical essence and purpose analogue of the present invention is thermal transfer paper for inkjet printing, consisting of a base paper and a barrier coating deposited on it containing a binder - sodium salt of carboxymethyl cellulose, polyvinyl alcohol, gelatin or their mixtures, and a filler - kaolin or talc or mixtures thereof in the following ratio of components (in mass): binder - 100, filler - not more than 15. On this coating by ink-jet printing with special sublimation ink image, dried under certain conditions for some time and then, under the influence of heat (170 ° -210 ° C) and pressure image is transferred from the paper to the fabric (US 6902779, 07.06.2005 g).

The disadvantages of the above paper are:

a) color mixing when printing images with fills of 200% or more in the print mode of 360 * 720 dpi or higher at the interface of these colors during printing, i.e. interpenetration of ink (up to 1-2 mm) in the area with a different color, causing a decrease in print sharpness. This drawback is especially noticeable at the border of red and green colors when printing bright dies;

b) the unevenness of sealing dies with mixed colors when printing images with fills from 200%, for example, green (a mixture of blue and yellow) or red (a mixture of purple and yellow) in printing mode from 360 * 720 dpi and above;

c) severe deformation of the paper when printing images with fills from 300% or more in the print mode from 360 * 540 dpi and above;

d) slow drying of the ink deposited on the barrier coating, which leads to high-fill ink to a wipe of ink on the back of the paper when winding it into a roll.

These drawbacks of this paper do not allow to obtain high-quality prints of the image on fabric or other surfaces intended for sublimation transfer when printing bright raster images.

The problem to which the proposed invention is directed, is to create a thermal transfer paper for inkjet printing with sublimation ink, which would eliminate the above disadvantages.

The technical result achieved by the implementation of this invention is as follows:

a) ensuring high drying speed of images sealed on paper in the entire range of densities of filling with sublimation ink, which makes it possible to print at the highest possible speed of modern high-speed plotters;

b) ensuring high color contrast and clarity of the image due to the absence of ink interpenetration in the area with a different color when printing adjacent areas painted in different colors, when printing images with fills of 200% or more in printing mode from 360 * 720 dpi and above;

c) ensuring high uniformity of sealing dies with mixed colors when printing images with fills from 200% in printing mode from 360 * 720 dpi and above;

d) ensuring high definition of the sealed image on paper due to the small dot spreading (fading) when a single drop of ink gets onto the surface of the coating by inkjet printing.

This makes it possible to use thermal transfer paper for printing by sublimation ink, obtained according to this invention, in addition to ordinary printing, in the production of various high-quality products with particularly vivid images, using inkjet printing methods, including when printing on high-speed plotters, with a productivity of up to 100 m ² per hour.

The specified technical result is achieved by the fact that the thermal transfer paper consists of base paper and a barrier coating, the main technical characteristics of the base paper being an ash content of 0.01-4%, a swelling within 1.6-2.0 cm ³ / g, and the barrier coating contains a binder and a filler, the binder being taken from the group of substances including starch, carboxymethyl cellulose, polyvinyl alcohol, gelatin, or mixtures thereof, and the filler contains finely divided diatomite powder and / or highly dispersed polymethyl methacrylate powder and additional substances taken from the group comprising kaolin, talc, finely divided starch, silica gels, or mixtures thereof. According to the invention, the binder and filler in the composition of the barrier coating are contained in the following ratio (parts by weight):

Binder - 100, filler - 100-200.

The mass of the barrier coating on paper-based is 4-8 g / m ² .

Thermal transfer paper is prepared as follows.

A predetermined amount of aqueous dispersions of fillers of a certain concentration are prepared in the mixer-reactor, each filler individually. The resulting aqueous dispersions are poured into temporary storage tanks.

In a mixer-reactor, a predetermined number of binders of a certain concentration are alternately prepared and poured into temporary storage tanks.

Aqueous dispersions of binders are alternately supplied to the mixer-reactor in the required proportion, then the necessary proportions of the fillers are fed in a certain sequence. The mixture is stirred for 15-20 minutes and filtered.

The resulting composition is applied to a base paper weighing from 60 to 110 g / m ² on a coating unit by any known and acceptable method. The coating weight may be from 4 to 8 g / m ² .

Example 1

The base paper is coated with (parts by weight)

Binder:

- carboxymethyl cellulose - 98

- polyvinyl alcohol - 2

- Filler:

- fine powder of diatomite - 50

- fine powder of polymethyl methacrylate - 25

- finely divided starch - 30

- kaolin - 3

Example 2

The base paper is coated with (parts by weight)

Binder:

- carboxymethyl cellulose - 100

- Filler:

- fine powder of diatomite - 50

- fine powder of polymethyl methacrylate - 28

- finely divided starch - 40

- talc - 4

Example 3

The base paper is coated with (parts by weight)

Binder:

- carboxymethyl cellulose - 97

- polyvinyl alcohol - 3

Filler:

- fine powder of diatomite - 120

- finely divided starch - 30

- kaolin - 3

Tests of samples of thermal transfer paper obtained by the proposed method are as follows.

Sealing of samples with sublimation inks of various brands is carried out on plotters Mimaki JV33, Mimaki JV4 and Mimaki TX400D with fill densities from 100% to 400%. At the same time, paper samples were sealed according to the Jetcol 3000 prototype of Coldenhove (Holland).

Sealing was carried out in 360 * 720 dpi mode.

When printing images on paper, the following parameters were checked:

- color contrast of the borders of the sealed dies, in particular, attention was paid to the borders of mixed colors, red and green;

- the uniformity of the sealing of the dies with mixed colors, in particular, attention was paid to the green dies;

- the clarity of the sealed image, in particular, attention was paid to capturing black (mixed) text (fill 400%) on a white background with a typographic font, the minimum size of which is 3 points, and capturing white text against a black (mixed) background (fill 400%) with a typographic font, the minimum size of which is 3 points;

- the degree of drying of the ink in the allowable time interval between the sealing and winding of the sealed web;

- the degree of deformation of the paper when printing with filling 300% or more.

During the thermal transfer of sealed images to the fabric, the following indicators were recorded:

- brightness of the image on the fabric;

- color contrast of the borders of the dies, in particular, attention was paid to the borders of mixed colors, red and green;

- the uniformity of the dies with mixed colors, in particular, attention was paid to the green dies;

- the clarity of the image on the fabric, in particular, attention was paid to the image of black (mixed) text (fill 400%) on a white background in typographic font, the minimum size of which is 3 points, and the image of white text on a black (mixed) background (fill 400%) typographic font, the minimum size of which is 3 points.

Table 1 shows the parameters of coated paper by examples.

Table 2 shows the characteristics of the sealing of images on paper by examples and prototype. The sealing performance on paper according to the prototype is taken as a standard and marked with a "*". For paper according to the invention, the signs ">", or "=", or "<" indicate that this or that indicator exceeds the corresponding indicator of paper in the prototype, is equal to or less than the indicator for the prototype.

Table 3 shows the characteristics of the transferred images on the fabric by examples and prototype. The performance of the image on the fabric of the prototype is taken as a standard and marked with a "*". For paper according to the invention, the signs ">", or "=", or "<" indicate that this or that indicator exceeds the corresponding indicator of paper in the prototype, is equal to or less than the indicator for the prototype.

Table 1 Example Coated Paper Specifications Example No. one 2 3 The mass of the base paper, g / m ² 80 90 one hundred Mass of coating, g / m ² 6 7 8

table 2 Characteristics of sealing images on paper by examples and prototype Example No. 360 * 720 dpi print mode
a) fill 100%
b) fill 200%
c) fill 300%
d) fill 400% Color Contrast Sealed Dice Borders Sealing uniformity with mixed colors Clarity of sealed image Ink drying time Deformation of paper when printing with filling and more Jetcol 3000 but) * * * * * b) * * * * * at) * * * * * d) * * * * * but) = = = < - one b) > > = < - at) = = > < < d) = = > < < but) = = = < - 2 b) = = = < - at) = = > < < d) = = > < < but) = = = < - 3 b) = = = < - at) = = = < < d) = = = < <

Table 3 Characteristics of thermal transfer of the image to the fabric by examples and prototype Example No. Print mode
360 * 720 dpi
a) fill 100%
b) fill 200%
c) fill 300%
d) fill 400% Image brightness on fabric Color Contrast Sealed Dice Borders Sealing uniformity with mixed colors Clarity of sealed image Jetcol
3000 but) * * * * b) * * * * at) * * * * d) * * * * one but) = = = = b) = > > = at) = = = > d) = = = > 2 but) = = = = b) = = = = at) = = = > d) = = = > 3 but) = = = = b) = = = = at) = = = = d) = = = =

Based on these tables, we can conclude that all types of thermal transfer paper for sublimation thermal transfer, manufactured according to the claimed proposal, in all respects are not inferior or superior to the paper on the prototype.

Thus, the paper according to the invention can be used to capture images with any degree of filling on plotters of various models, including modern plotters with a productivity of up to 100 m ² / hour, with the subsequent receipt of the final product of the highest quality.

Claims (4)

1. Thermal transfer paper for inkjet printing by sublimation ink, characterized in that it consists of a base paper and a barrier coating applied thereon containing a binder and a filler, the binder being selected from the group of substances including starch, carboxymethyl cellulose, polyvinyl alcohol, gelatin or their mixtures, and the filler contains fine powder of polymethyl methacrylate and / or fine powder of diatomite and additional substances selected from the group comprising kaolin, talc, fine to Ahman, silica or mixtures thereof. 2. Thermal transfer paper according to claim 1, characterized in that the base paper has an ash content of 0.01-4% and a swelling in the range of 1.6-2.0 cm ³ / g. 3. Thermal transfer paper according to claim 1, characterized in that the binder and filler are contained in the following ratio, parts by weight:
binder one hundred filler 100-200 4. Thermal transfer paper according to claim 1, characterized in that the mass of the barrier coating on a base paper is 4-8 g / m ² .