KR102528180B1 - Transfer paper for ink-jet printing and preparation method thereof - Google Patents

Abstract

The present invention relates to inkjet transfer paper suitable for high-quality, high-speed output.
Inkjet transfer paper according to the present invention improves ink drying, transfer density and transfer efficiency to meet the needs of high-speed printers, improves the fluidity of the coating liquid (coating color), so the production speed can be improved, and various paper method can be easily applied.

Description

Inkjet transfer paper and its manufacturing method {TRANSFER PAPER FOR INK-JET PRINTING AND PREPARATION METHOD THEREOF}

The present invention relates to paper for high-quality, high-speed printing, and more particularly, to an inkjet transfer paper capable of improving the drying property and transfer density of ink and a method for manufacturing the same.

In the early 2000s, there were only a handful of companies producing inkjet sublimation transfer paper (hereinafter referred to as “transfer paper”) at home and abroad, but based on the convenience, economy, and high quality of inkjet sublimation transfer paper technology, the textile market and the dyeing market and Inkjet sublimation transfer paper technology is rapidly replacing the gravure transfer paper market. Compared to existing technologies, inkjet sublimation transfer paper has a relatively simple process, can express various colors, and is economically suitable for small-lot production of various types, and has established itself as a production method suitable for the textile market, where production lots are gradually decreasing.

As the inkjet sublimation transfer paper technology develops, technological development is progressing rapidly not only in the transfer paper but also in the printer market, which is hardware. As long-width high-speed printers that overcome the limitations of width and low output speed, which were the disadvantages of inkjet printers, have become commonplace, it is urgently required to secure the quality of transfer paper suitable for high-speed printers.

Conventionally, a method of adjusting the porosity of base paper has been applied for quick drying of ink, but this method can be applied only to a papermaking method using a Yankee dryer, and a general fourdrinier papermaking method or gap former There is a limitation that it cannot be applied to the (gap former) type grassland method. In addition, the composition used in the conventional inkjet sublimation transfer paper has a problem in that the fluidity (rheology) of the coating solution (coating color) is lowered due to the characteristic of high viscosity and the drying load due to the low solid concentration.

Therefore, it is necessary to develop a product that is easy to apply in a general papermaking method while improving the quality of inkjet sublimation transfer paper designed for the existing low-speed printing machine to be suitable for high-speed printing inkjet sublimation transfer paper.

An object of the present invention is to provide inkjet transfer paper capable of improving ink dryness and transfer density in order to improve quality at the time of high-speed printing.

Another object of the present invention is to provide a method for manufacturing the inkjet transfer paper.

In order to achieve the above object, the present invention is a configuration of a transfer coating layer,

An inkjet transfer paper comprising 50 to 200 parts by weight of granular starch based on 100 parts by weight of the thickener is provided.

According to one embodiment, based on 100 parts by weight of the thickener, 60 to 100 parts by weight of granular starch may be included.

According to one embodiment, the thickener may be Na-CMC having a degree of substitution (DS) of 0.6 to 1.0.

According to one embodiment, the average particle diameter (D50) of the granular starch may be 10 to 50 μm.

According to one embodiment, the granular starch may be non-gelatinized starch containing at least one selected from the group consisting of modified starch, raw starch, and starch derivatives.

According to one embodiment, a back coating layer may be further provided on the other side of the base paper layer on which the transfer coating layer is not applied.

According to another embodiment of the present invention, based on 100 parts by weight of the thickener, 50 to 200 parts by weight of granular starch is mixed with water at room temperature and applied to one side of the base paper layer to form a transfer coating layer, inkjet transfer paper Provides a manufacturing method of.

According to one embodiment, the method may further include forming a back coating layer on the other side of the base paper layer on which the transfer coating layer is not formed.

According to one embodiment, the transfer coating layer may be formed in one layer or two layers on one side of the base paper layer.

According to one embodiment, the coating amount after drying of the transfer coating layer may be 1 to 10 g/m 2 .

According to one embodiment, the air permeability (porosity) of the base paper layer measured by the Gurley method may be 20 to 60 seconds. In addition, the air permeability of the transfer paper on which the transfer coating layer is formed may be 3,000 to 12,000 seconds.

According to one embodiment, as a coating method for forming the transfer coating layer, at least one selected from the group consisting of an air-knife, a wire wound rod, and a curtain coating method is used. can include

Other specific details of implementations according to the present invention are included in the detailed description below.

Inkjet transfer paper according to the present invention improves ink drying, transfer density and transfer efficiency to meet the needs of high-speed printers, and improves the fluidity of the coating liquid (coating color) so that the production speed can be improved. method can be easily applied.

1 to 5 are photographs of the coating layer showing the distribution of particles according to the type and size of granular starch.
6 is a photograph of a coating layer showing the distribution of particles according to the content of granular starch.

Since the present invention can apply various transformations and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, it should be understood that this is not intended to limit the present invention to specific embodiments, and includes all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the present invention, if it is determined that a detailed description of related known technologies may obscure the gist of the present invention, the detailed description will be omitted.

Unless otherwise specified within this specification, the expression "to" is used as an expression including the corresponding numerical value. Specifically, for example, the expression “1 to 2” means not only including 1 and 2, but also including all numbers between 1 and 2.

Hereinafter, the present invention will be described in more detail.

Specifically, the inkjet transfer paper according to the present invention provides inkjet sublimation transfer paper in which a transfer coating layer containing 50 to 200 parts by weight of granular starch is formed on one side of the base paper layer with respect to 100 parts by weight of the thickener.

The transfer coating layer serves to receive ink printed by inkjet printing and release the ink when appropriate heat and pressure are applied. If the printed ink does not dry quickly, the image may be offset on the back side of the paper when the transfer paper on which the image is printed is rolled up and manufactured into a roll, thereby deteriorating image quality and causing a ghosting phenomenon in the later transferred image. The ghost phenomenon refers to a phenomenon in which an afterimage of an unintended image appears.

Therefore, in order to improve the sharpness of the image to be transferred, the printed ink needs to be quickly absorbed and dried on the transfer paper.

In addition, the ink absorbed in the transfer coating layer must be sufficiently transferred to an object to be transferred (eg, fabric) when necessary.

According to one embodiment, based on 100 parts by weight of the thickener, granular starch may be included in an amount of 50 parts by weight or more, and also 60 parts by weight or more, for example, 200 parts by weight or less, 150 parts by weight or less, or 100 parts by weight or more. If the content of the granular starch is too low, the drying speed of the ink may decrease, and if the content is too high, the transfer efficiency may decrease due to the high residual concentration of the ink.

In addition, the degree of substitution (DS) of Na-CMC that can be used as the thickener may be 0.6 to 1.0, for example, 0.6 or more, 0.7 or more, 0.8 or more, for example 0.95 or less. . If the degree of substitution is too low, barrier performance may deteriorate, resulting in a decrease in transfer rate and transfer concentration.

In general, a lot of starch is used in the manufacturing process of paper. Starch may be added together with other raw materials as a binder for binding the cellulosic fiber material originating from the pulp before the paper is formed, or applied to the outer surface of the paper after the paper is formed. However, the form of using starch in the existing papermaking process is to mix starch with a solvent and then use it in a gelatinized state by heating. In the present invention, a coating layer is formed on the outer surface of paper in a non-gelatinized state after mixing starch in a granular state with a thickener. By doing so, the starch particles can simultaneously serve as a filler without using a separate inorganic filler (eg, calcium silicate, talc, calcium carbonate??, aluminum-magnesium silicate, etc.). The present inventors have completed the present invention by finding that drying properties and transfer efficiency can be simultaneously improved by using non-gelatinized granular starch, and that the drying load can be reduced due to the high concentration of the coating solution.

According to one embodiment, the average particle diameter of the starch may be 10 to 50 μm, for example, 10 μm or more, 20 μm or more, 30 μm or more, or 50 μm or less, 40 μm or less, 30 μm or less, or 20 μm or less. Also, specifically, for example, it may be 10 to 20 μm. If the size of the starch particles is too small, the effect of improving drying properties may be insufficient, and if the size of the starch particles is too large, they may stick to the surface of the coating layer and cause contamination.

The starch may include at least one selected from the group consisting of modified starch, raw starch, and starch derivatives.

Modified starch may include cationic starch, oxidized starch, esterified starch, etherified starch, and the like. Raw starch may include wheat starch, corn starch, sweet potato starch, potato starch, tapioca starch, wheat flour starch, and the like. Starch derivatives may include dextrins and the like. The starch of the present invention may include, for example, etherified starch.

Specifically, for example, cationic starch may include tertiary cationic starch, quaternary cationic starch, and the like, and may include, for example, aminoalkyl starch, but is not limited thereto.

Oxidized starch may include, but is not limited to, hypochlorous acid oxidized starch, dialdehyde starch, and the like.

Modified starches include esterified starch, etherified starch, Acetylated Distarch Adipate, Acetylated Distarch Phosphate, Starch Sodium Octenyl Succinate, and Distarch Phosphate. Phosphate), Monostarch Phosphate, Phosphated Distarch Phosphate, Starch Acetate, Hydroxypropyl Distarch Phosphate, Acid Decomposed Starch, Acid Treated Starch, α Transformed starch, soluble starch α-transformed starch, dextrin, cross-linked starch, and the like may be included, but are not limited thereto.

According to a preferred embodiment of the present invention, the starch may be cationic starch, oxidized starch, esterified starch or etherified starch, particularly preferably esterified starch.

According to another embodiment of the present invention, there is provided a method for manufacturing inkjet transfer paper, comprising forming a transfer coating layer by mixing 50 to 200 parts by weight of granular starch with respect to 100 parts by weight of the thickener at room temperature.

According to one embodiment, the transfer coating layer may be formed in one layer or two layers on one side of the base paper layer.

According to one embodiment, the air permeability (porosity) of the base layer measured by the Gurley method may be 20 to 60 seconds. In addition, the basis weight may be 30 g/m ² or more, 40 g/m ² or more, or 50 g/m ² or more and 100 g/m ² or less.

According to one embodiment, the coating amount after drying of the transfer coating layer according to the present invention may be 1 to 10 g/m 2 , for example, 2 g/m 2 or more, 3 g/m 2 or more, 8 g/m 2 or less, or 5 g/m 2 or less. .

In the range of air permeability and basis weight as described above, it is advantageous in that the output ink remains on the surface of the transfer coating layer (hold out) by reducing the degree of absorption of the ink of the coating layer into the base paper layer and speeding up the ink drying speed. It is also advantageous in terms of the barrier side of the back side of the transfer paper by reducing the permeation of the sublimation ink to the back side of the transfer paper during transfer.

In addition, the air permeability of the transfer paper on which the coating layer is formed may be 3,000 to 12,000 seconds as measured by the Gurley method.

The term 'base paper' or 'base paper layer' used herein refers to paper made of a cellulose fiber material derived from pulp, before any coating layer is formed.

The coating method for forming the transfer coating layer may include at least one selected from the group consisting of an air-knife, a wire wounded rod, and a curtain coating method.

In addition, the coating amount of the transfer coating layer is 1 to 10 g / m 2, for example, 1 g / m 2 or more, 2 g / m 2 or more, 3 g / m 2 or more, and 10 g / m 2 or less, 8 g / m 2 or less, 5 g / m 2 or less, It may be 4 g/m 2 or less.

In addition, according to one embodiment, a back coating layer may be further formed on the opposite side of the base paper layer on which the transfer coating layer is formed. The back coating layer is formed by applying a mixture of starch, polyvinyl alcohol, clay, or a pigment such as talc. can be effectively prevented. Since the starch used in the white coating layer is dissolved in water and applied to the other side of the base paper layer in a gelatinized state by heating or the like, it must be distinguished from the starch inside the transfer coating layer applied in a non-gelatinized granular form.

Hereinafter, preferred embodiments are presented to aid understanding of the present invention, but the following examples are only illustrative of the present invention, and the scope of the present invention is not limited to the following examples.

Examples 1 to 5 and Comparative Examples 1 to 5

A coating layer composition was prepared with the composition shown in Table 1.

Specifically, Na-CMC and modified starch powder (average particle diameter of 13-14um, spherical esterified starch particles) were put into a mixing container, water was poured at room temperature according to the concentration and stirred vigorously to prepare a coating layer composition, confirmed.

Base paper having a Gurley permeability of 20 to 60 seconds was prepared. After applying the coating layer composition to the surface of the base paper using a load bar and drying it, the weight was measured to confirm the coating amount.

Experimental Example 1: Evaluation of transfer paper

Transfer paper coated with each coating layer composition is set in an inkjet printer, and a standard image is printed using MIMAKI JV-33, 160A, Inktech ink, and then the transfer paper printed on a hot plate and the transfer paper to be transferred are printed. In order to prevent the hot plate from being contaminated due to the phenomenon that the transfer ink bleeds out to the back of the fiber during the transfer process by overlapping the fibers (polyester), white paper for anti-contamination is added to the back of the fiber, and then flat plate transfer at 200 ° C, 20 psi, 35 sec. (Air Fusion) was performed and the transfer quality was evaluated.

The concentrations of the transferred fibers and the four color (CMYK) parts on the transfer paper remaining after transfer were measured with an optical densitometer.

Transfer density means the density of the color transferred to the fiber evaluated by G. macbeth Spectro Eye, residual density means the density of the color remaining on the transfer paper after transfer, and output density means the transfer through the inkjet printer It means the density of the color printed on the paper.

The transfer rate is (1-residual rate)% and the residual rate (%) is calculated as residual concentration/output concentration*100.

Dryness (5-point method) is (after 30 seconds have elapsed after printing 5 standard images (5 cm wide, 3 cm long), cover the standard image with white paper every 15 seconds and reciprocate 5 times with a rubber roller to print the image that is smeared on the white paper. It was photographed with a digital camera, and the degree of dryness in 5 places was compared with the limit sample for relative evaluation with the naked eye.

The transfer quality evaluation results for the 100g/m ² composition in Table 1 are in Table 2, the results of the 80g/m ² composition are in Table 3, the results of the 70g/m ² composition are in Table 4, and the results of the 57g/m ² composition are in Table 3. In Table 5, the results of the 45 g/m ² composition are shown in Table 6.

Experimental Example 2: Observation of transfer paper

In order to confirm the drying improvement effect according to the shape and size of starch particles, transfer paper coated with each composition as shown in Table 7 was used.

Specifically, 2.5 g/m ² of CMC and starch mixture was applied to one side of the base paper using a load bar, and then observed with an electron microscope (JEOL, FE-SEM) and shown in FIGS. 1 to 5.

According to the above results, the larger the starch particles, the more difficult it is to apply due to limitations in the coating method, and the particles protrude out of the coating layer after coating, which may contaminate the head during inkjet printing. Conversely, if the particles are too small, the drying improvement effect is reduced.

The difference according to the shape of the particle is not large, but the spherical shape is more suitable for the coating method.

Comparative Example 6

Except for the application of the composition shown in Table 8, the Gurley air permeability was 21.3 seconds and the basis weight was 65 g/m ²

A coating layer was formed on base paper in the same manner as in Example, and evaluated in the same manner as in Experimental Example 1.

Air permeability was measured with the L&W Air Permeability measurement facility.

The evaluation results when clay was applied are shown in Table 9.

Comparative Example 7

Except for applying the composition shown in Table 10, a coating layer was formed in the same manner as in Example for base paper having a Gurley air permeability of 21.3 seconds and a basis weight of 65 g / m ² , and evaluated in the same manner as in Experimental Example 1.

Air permeability was measured with the L&W Air Permeability measurement facility.

As shown in Tables 9 and 10, when using a pigment such as clay or silica, it can be seen that the quality is lowered in terms of transfer rate, transfer concentration, residual concentration, and dryness compared to the example using starch particles.

According to the above results, it was confirmed that the dryness of the inkjet transfer paper according to the present invention is improved to improve transfer density, residual density, output density and transfer rate.

In the above, the specific contents of the present invention were examined. It is clear to those of ordinary skill in the art to which the present invention belongs that these specific techniques are only one preferred aspect, and the scope of the present invention is not limited thereby.

Claims (12)

Inkjet transfer paper comprising 100 to 150 parts by weight of non-gelatinized granular starch based on 100 parts by weight of the thickener and having a transfer coating layer formed on one side of the base paper layer and not containing a separate inorganic filler. delete According to claim 1,
The thickener is Na-CMC having a degree of substitution (DS) of 0.6 to 1.0, inkjet transfer paper. According to claim 1,
Inkjet transfer paper, wherein the average particle diameter of the non-gelatinized granular starch is 10 to 50 μm. According to claim 1,
Inkjet transfer paper, wherein the non-gelatinized granular starch is non-gelatinized starch containing at least one selected from the group consisting of modified starch, raw starch, and starch derivatives. According to claim 1,
Inkjet transfer paper, further comprising a back coating layer on the other side of the base paper layer to which the transfer coating layer is not applied. Forming a transfer coating layer by mixing 100 to 150 parts by weight of non-gelatinized granular starch with water at room temperature and applying a coating solution to which no inorganic filler is added to one side of the base paper layer with respect to 100 parts by weight of the thickener , Method for manufacturing inkjet transfer paper. According to claim 7,
The method of manufacturing inkjet transfer paper, further comprising forming a back coating layer on the other side of the base paper layer on which the transfer coating layer is not formed. According to claim 7,
The method of manufacturing inkjet transfer paper, wherein the transfer coating layer is formed in one or two layers on one side of the base paper layer. According to claim 7,
A method for producing inkjet transfer paper, wherein the coating amount after drying of the transfer coating layer is 1 to 10 g / m 2 . According to claim 7,
Method for producing inkjet transfer paper, wherein the air permeability measured by the Gurley method of the base paper layer is 20 to 60 seconds. According to claim 7,
As a coating method for forming the transfer coating layer, an inkjet comprising at least one selected from the group consisting of an air-knife, a wire wound rod, and a curtain coating method. Method for manufacturing transfer paper.

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