RU2335405C1 - Thermal transfer paper for printing with sublimation ink - Google Patents

Abstract

FIELD: technological processes.

SUBSTANCE: this paper for printing consists of base and coating applied on it, which contains binding agent and filler. At that components are contained with preset proportion. As binding agent coating contains substance selected from the group that includes starch, carboxymethylcellulose, polyvinyl alcohol, gelatine and their mixtures. As filler coating contains substance selected from the group that includes calcium sulfoaluminate, fine-grained starch, talc, silica gels and their mixture. Mass of coating on paper base amounts to 10-25 g/m². Possibility occurs to use thermal transfer paper in production of different items with firmly printed colour images, both with application of jet printing method and typography printing methods.

EFFECT: provision of high rate of ink drying and images printed with them on paper in the complete range of ink densities.

4 cl, 3 tbl, 3 ex

Description

The invention relates to the pulp and paper industry and can be used in the manufacture of thermal transfer papers.

Known two-layer material for thermal transfer of printed images, including a flexible first layer, for example a cellulosic non-woven fabric (paper), and a second layer deposited on the first layer and connected with it, for example, by means of glue or heating.

The second layer is a fabric obtained from a natural or synthetic polymer, for example, by melt blowing of a polyamide with a melting point of 90 to 250 degrees C.

The second layer is treated with a composition containing water and a substance, for example polyvinyl alcohol or polyoxyethylene, which increases the viscosity of inkjet ink on the surface of the second layer to obtain a durable image printed on it.

The transfer of the printed image to the fabric is carried out by transferring the molten second layer with a mass of at least 10 g / m ² using heating and pressure. (RU, application 99122675/12, published on 10/10/2001).

The disadvantage of this material is that the image is transmitted to the receiving fabric along with a polymer film with dyes fused into it.

As a result, images on the fabric are obtained with low contrast, blurry borders of colors. In addition, the colorful image on the final textile product quickly collapses together with the polymer film that carries the image during mechanical action on the product, for example, during washing.

The closest to the proposed paper by its technical nature and purpose 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 in the following ratio of components (in mass):

binder - 100; filler 17.6.

An image is applied to this coating by ink-jet printing using special sublimation inks, dried under certain conditions for some time, and then, under the influence of heat and pressure, the paper carrying the printed image comes into contact with the fabric (US Pat. No. 6902779, IPC B41M 5/40, published on June 7, 2005).

The disadvantages of the mentioned paper are the slow drying of the ink deposited on the barrier coating, which leads to high ink densities to smear ink on the back of the paper when winding it into a roll, mixing some colors at the interface of these colors during printing, that is, the penetration of one ink (1-2 mm) in the area with a different color, causing a decrease in print contrast, as well as an insufficiently high degree of ink transfer during thermal transfer of printed images.

In addition, the quality of the printout on paper and, accordingly, the image on the fabric depends on the type of sublimation ink used.

The technical result achieved by using the present invention consists in a higher speed of ink absorption and drying processes, high contrast of color separation lines due to the exclusion of mixing of paints on the separation lines, the elimination of the fading of paints in rolls and when transferring images to a fabric, a higher degree of ink transfer when thermal transfer to fabric, the possibility of using all known types of sublimation ink when printing on high-speed plotters.

The specified technical result is achieved in that the thermal transfer paper, consisting of a base paper and a coating containing a binder and a filler, the binder is taken from the group of substances including carboxymethyl cellulose, polyvinyl alcohol, gelatin and mixtures thereof, and the filler is taken from the group of substances including talc , kaolin, according to the invention, contains a binder and a filler in the coating composition in the following ratio (parts by weight):

binder - 100, filler 30-500.

The binder may include one of these substances or a mixture of these substances in any combination: carboxymethyl cellulose and polyvinyl alcohol; carboxymethyl cellulose and gelatin; gelatin and starch.

The group of binders used in the coating further comprises starch.

The group of fillers used in the coating further comprises calcium sulfoaluminate, silica gels, finely divided starch and mixtures of these substances.

The coating weight on a paper base is 10-25 g / m ² .

Thermal transfer paper is prepared as follows.

In the mixer-reactor, a predetermined amount of an aqueous binder solution of a certain concentration is prepared. Then, a predetermined amount of filler is fed into the solution with vigorous stirring. After the filler is discontinued, the mixture is stirred for 10-15 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 method. The coating weight may be from 10 to 25 g / m ² .

Example 1

The base is coated, containing (in parts by weight)

- binder - carboxymethyl cellulose - 15;

- polyvinyl alcohol - 70;

gelatin - 15;

- filler - kaolin - 20, talc - 10.

Example 2

The base is coated, containing (in parts by weight)

- binder - carboxymethyl cellulose - 100;

- filler - kaolin - 250.

Example 3

The base is coated, containing (in parts by weight)

- binder - starch - 50;

carboxymethyl cellulose - 25;

- polyvinyl alcohol - 15;

- gelatin - 10;

- filler - kaolin - 300, calcium sulfoaluminate - 50, talc - 25, silica gel - 50, finely dispersed (non-gelatinized) starch - 75.

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

Different types of sublimation inks (Manoukian, Expressio, CIBA) are sealed using a Mimaki JV22-160, JV4-160 plotter with fill densities from 100 to 400%. At the same time, that is, under absolutely the same conditions, paper samples are sealed according to the prototype Coldenhove Jetcol from Coldenhove (Holland).

To further evaluate the quality of thermal transfer paper made according to the invention, as well as to determine the possibility of using it when printing images on high-speed plotters of new generations, we used a special method developed for this.

According to this method, a poster pen 12-15 mm wide was carried out on test papers (including prototype paper) with the same speed and pressure of an ink strip of different colors and types. The amount of ink in the pen in all cases was the same and sufficient so that there were zones of all possible ink fill densities in the strip.

In our tests, the fill density in the line gradually varied from the maximum (similar to 800% of the fill) at the beginning of the line to the minimum (10-15% of the fill) at its end.

The specific value of the fill density in the areas of the poster lines was approximately determined by comparing the drying time of the ink until the disappearance of the ink from the lines sealed on the plotter until the disappearance of the ink in the areas of the poster lines with similar fill densities. Comparison of the drying speed of ink with a high density of filling on the papers according to the invention and the prototype, all other things being equal, the seals and images on the fabric after thermal transfer shows the advantage of this or that paper when printing on a high-speed plotter.

In addition to the speed (duration) of ink drying, during testing of all papers during recording, the following indicators were recorded and compared:

- uniformity of coloring of images directly when printing on a plotter or a poster pen (ripples, stripes, ink curl, paper impregnation are possible);

- maintaining uniformity and density of staining during the process of absorption - drying of ink;

- contrast of the borders of the lines of one color or dividing lines of two colors (at high densities of filling, "double" lines of one color or dividing lines of two colors, the flow of ink of one color into ink of another color when printing on a plotter are possible);

- the completeness of drying of the ink at an acceptable time interval between the sealing and the winding of the sealed web of paper in a roll.

During thermal transfer of images qualitatively sealed on a plotter onto a fabric, the following indicators were recorded:

- the degree of transfer of dyes from paper to fabric;

- the brightness and density of the colors of the images on the fabric;

- the appearance of image defects on the fabric, not available on sealed paper.

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 by prototype. The sealing performance on paper according to the prototype is taken as a standard and marked with a "*". For securities according to the invention, the signs ">" or "=" indicate that one or another indicator exceeds the corresponding indicator of the paper on the prototype or equal to it.

Table 3 compares the degree of transfer of dyes from paper to fabric, as well as the quality of images on fabric when used for thermal transfer of paper according to the invention and the prototype. The meaning of the icons is similar to that used in table 2.

Table 2 and 3 also show the data when printing lines with a poster pen. In the initial part of the lines, the fill density is approximately 800%.

Given the values of the drying time, it can be assumed that the ink on the paper according to the prototype at an increased fill density (above 400%) does not have time to dry before the disappearance of the decoction for an acceptable period of time between printing images on a high-speed plotter before the paper is rolled up.

Based on these tables, we can conclude that papers made according to the claimed proposal, in all respects, are not inferior to or superior to paper by prototype. The significantly higher speed of the process of absorption and drying of ink while maintaining high rates of images sealed on paper and transferred to the fabric allows the use of high fill densities, achieved, for example, when sealing on high-speed plotters of new generations.

Thus, the paper according to the invention can be used to capture images with any degree of filling on plotters of various models with the subsequent receipt of the final product (for example, fabric products with images transferred to them) of high quality. You can print images on paper for further thermal transfer to the fabric using inkjet printing methods as well as typographic printing methods.

Table 1. Example Coated Paper Specifications No. of examples one 2 3 The mass of paper - the basics, g / m ² 60 90 110 Mass of coating, g / m ² 10 eighteen 25

Table 2. Characteristics of sealing images on paper by examples №№ Print mode Uniformity Duration Definition an example staining drying out the borders dice ink up lines disappearances section otmar (without flowers forced (contrast heating) on the fill min 800%) one but) = 2 = 2 but) = one = b) > 2 > at) 3 3 but) > 0.5 = b) > 1,5 > at) > 2 > Prototype but) * 6 * b) * 10 * Jetcol at) * 12 * 2000 Jetcol but) * four = 5000 b) * 8 > at) * 10 > a) 360 dpi × 360 dpi 2 passes b) 360 dpi × 540 dpi 3 passes c) 360 dpi × 740 dpi 4 passes

Table 3. The degree of transfer of dyes from paper to fabric and quality indicators of images transferred to fabric when using paper according to examples and prototype. No. of examples The degree of dye transfer in% The brightness of the colors in the image (visual) Image defects 1 a) = = = 2 a) = = = 2 b) > > > 3 a) = = = 3 b) > > > 3 c) > > > Jetcol 2000 prototype but) * * * b) * * * at) * * * Jetcol 5000 prototype but) = = = b) = = > at) = = > The designations of modes a), b), c) are shown in table 2.

Claims (4)

1. Thermal transfer paper for printing by sublimation ink, consisting of a base and a coating containing a binder and a filler, the binder being taken from the group of substances including carboxymethyl cellulose, polyvinyl alcohol, gelatin and mixtures thereof, and the filler is taken from the group of substances including talc, kaolin, characterized in that the binder and filler in the coating are contained in the following ratio, parts by weight: binder one hundred filler 30-500 2. Thermal transfer paper according to claim 1, characterized in that the group of binders further comprises starch. 3. Thermal transfer paper according to claim 1, characterized in that the group of fillers further comprises calcium sulfoaluminate, silica gels, finely divided starch and mixtures of these substances. 4. Thermal transfer paper according to claim 1, characterized in that the coating mass is 10-25 g / m ² .