KR100590358B1 - Thermal recording material - Google Patents

Abstract

The present invention relates to a thermal recording material having a three-layer structure of an under layer, a thermal layer, and an over layer on a support, and a back layer designed on the back of the support.

The overlayer designed on the heat-sensitive layer is composed of fillers to improve the resolution of the heat-sensitive surface and prevent sticking, wetting enhancers and dyes for coloring.In particular, colored dyes can be used to make colored thermal paper of various colors. There is a merit that a heat-resistant recording material having excellent abrasion resistance can be obtained. The specific composition of the overcoating layer is 200 to 300 parts by weight of polyvinyl alcohol (10% solution) and 50 to 100 parts by weight of aluminum hydroxide (15-30% solution). 15-30 parts by weight of an antifoaming agent (2-5% solution), 50-80 parts by weight of a wet strength improving agent (10-15% solution), 2-5 parts by weight of a lubricant (36% solution), red anionic colored dye ( RED) dye (20% liquid) of 0.1 to 0.5 parts by weight, and yellow (YELLOW) dye (30% liquid) of 0.6 to 1.2 parts by weight.

Thermal recording material, colored thermal paper, under layer, thermal layer, over layer, white layer

Description

Thermal Recording Material {THERMAL RECORDING MATERIAL}             

1 is a view showing a method for testing the wearability of the surface of the thermal recording material.

2 is a view showing a method for testing the surface binding force of the thermal recording material.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal recording material, and more particularly, to a thermal recording material having excellent abrasion resistance due to repeated use by making a desired color useful in a conventional white thermal recording material and improving a background printing.

BACKGROUND ART [0002] Conventional thermal recording materials have been applied to a wide range of industrial applications such as measurement recorders, word printer terminal printers, fax machines, barcode labels, trains, and the like, by forming a thermal layer by coating a thermal solution on a sheet of paper. Recently, various recording materials have been researched, developed and put into practical use in the information recording field due to the diversification of information and the expansion of new fields. Among them, the thermal recording material can easily record images only by the heating method. This has the advantages of simple mechanism, small size, easy handling of recording material, and low cost. Such a thermal recording material usually designs a layer containing a coloring component that causes a color reaction by heating on the support using paper as a support. Here, an under layer is designed between the support and the heat-sensitive layer to prevent color development of the non-image portion and discoloration of the image portion, and the under layer includes a conventional water-soluble resin and a chemical-resistant aqueous emulsion (patent patent). 083457). In order to increase sensitivity, prevent sticking, reduce gas adhesion, and maintain good coating strength, the underlayer is coated with a heat-sensitive coating solution containing pigments, lubricants, crosslinking agents and other auxiliary chemicals. If the product is used repeatedly for several times or tens of times, such as a thermal ticket, or in other background printing fields, the printing surface may be easily dropped, and additional processes requiring background printing may be required, resulting in complicated processes. .

The object of the present invention is to study the problems of the prior art as described above, using a base paper, PVC, YUPO fabric, etc. as a support, and by adding a color dye to the overlayer white The present invention provides a heat-sensitive recording material that can produce desired colors, and does not require an additional process of background printing, and has excellent wear resistance according to long-term and repeated use.

The present invention is based on a three-layer structure of an under layer, a thermal layer, and an over layer on a support, and designs a back layer on the back of the support. The overlayer designed on the heat-sensitive layer is composed of layered material for improving the resolution of the heat-sensitive surface and preventing sticking, a wet strength improver, and a dye for coloring. In particular, it is possible to make colored thermal paper of various colors through anionic colored dyes and to obtain a thermal recording material having excellent wear resistance.

In order to realize the object of the present invention, the present invention will be described below.

The present invention consists of an undercoating layer, a leuco dye, a heat-sensitive coating layer containing a developer, and an overcoating layer on the front surface, and a back layer on the back side.

The overcoating solution of the present invention comprises 200 to 300 parts by weight of polyvinyl alcohol (10% solution), 50 to 100 parts by weight of aluminum hydroxide (Al (OH) ₃ ) (15 to 30% solution), and an antifoaming agent (2 to 5% solution). ) 15 to 30 parts by weight, 50 to 80 parts by weight of wet strength improver (10 to 15% solution), 2 to 5 parts by weight of lubricant (36% solution), and anionic colored dyes. RED) 0.1 to 0.5 parts by weight of a dye (20% liquid) and 0.6 to 1.2 parts by weight of a yellow (YELLOW) dye (30% liquid), which is composed by adding water so as to be 8 to 10% by solid content. At this time, the polyvinyl alcohol should be composed of aluminum hydroxide and the amount of more than one to one in solid content.

In the present invention, when the polyvinyl alcohol is added more than the composition ratio, the resistance to plasticizer (tolerant to the wrap, eraser, etc. containing the plasticizer material) is relatively improved, but relatively long time is required for the surface to harden, In storage at high temperature and high humidity, the front and back surfaces stick to each other, sticking occurs during color development, noise is severe, and the image is not good, and it adversely affects the THERMAL PRINING HEAD. On the contrary, when polyvinyl alcohol is added in less than the composition ratio, the binding force is weakened, causing the coated surface of the surface to peel off due to repeated use, or to the plasticizer. In addition, when the amount of aluminum hydroxide is more than the composition ratio, the amount of binder decreases relatively, and the binding power is weakened. When the amount of aluminum hydroxide is less than the composition ratio, smoothness is worsened, resulting in a decrease in resolution of the image.

Antifoaming agent in the composition of the present invention is 2,4,7,9-tetramethyl-5-decine-4,7-diol (2,4, 7,9-tetramethyl-5-decyne-4,7-diol) The wet strength improver is used alone, and polyamide epichloro hydrin resin is used. The red (RED) dye uses PERGASOL RED 2G LIQ. From CIBA SPECIALTY CHEMICALS LTD, and the yellow dye is the PERGASOL YELLOW GA from CIBA SPECIALTY CHEMICALS LTD. Use LIQ.

In the preparation of the overcoating solution used in the present invention, 70% of the total amount of aluminum hydroxide, 70% of the total polyvinyl alcohol and 70% of the antifoaming agent are added, the solid content is adjusted to 10% with water, and the mixture is sufficiently dispersed and dispersed. And pulverize the liquid to an average particle diameter of 0.8 to 1.5 µm, and add the remaining 30% of polyvinyl alcohol, 30% of an antifoaming agent, a wet strength improver, and a lubricant. Color dyes are added last. At this time, if two kinds of dyes are added at the same time or if they are added to each or dilution together in water, agglomeration of liquid occurs and wrinkle-like stains occur on the surface after application. One should be added first, then completely mixed and the other dye added. The order of the colored dyes added is irrelevant and red and yellow dyes are sufficient if they have anionic properties. If cationic dyes are used, precipitates are formed by coagulation and staining occurs on the coated surface. Apply about ² to 5 g / m ² of dry weight part on the heat-sensitive layer formed on the support so that the final solid content is about 8 to 10%.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

(Examples 1 and 2)

                                                       (Parts by weight)

 Component Material  Example 1  Example 2  Aluminum hydroxide (25% liquid)  75  75  water  235  106  Polyvinyl alcohol (10% liquid)  250  250  Wet Strength Enhancer (10% Liquid)  60  60  Antifoaming agent (2% amount)  20  20  Lubricant (36% amount)  3  3  Red dye (20% liquid)  0.2  0.2  Yellow (YELLOW) dye (30% liquid)  0.8  0.8  Solid content (%)  8%  10%

The antifoaming agent in the above constitution is 2,4,7,9-tetramethyl-5-decine-4,7-diol (2,4,7,9-tetramethyl-5-decyne-4,7-diol), wet The intelligence enhancer is polyamide epichloro hydrin resin, the red dye is PERGASOL RED 2G LIQ. From CIBA SPECIALTY CHEMICALS LTD, and the yellow dye is YELLOW. PERGASOL YELLOW GA LIQ. From CIBA SPECIALTY CHEMICALS LTD.

First, polyvinyl alcohol is dissolved in water to have a solid content of 10%, 70% of aluminum hydroxide, 70% of total polyvinyl alcohol and 70% of antifoaming agent are added, and the mixture is sufficiently mixed with 10% of solid content with water. Grind through a milling machine to achieve an average particle diameter of 0.8-1.5 μm, and then mix and disperse the remaining 30% polyvinyl alcohol, 30% antifoaming agent, wet strength improver, and lubricant in order. . The antifoaming agent is more effective when dissolved in water separately. Into the coating solution thus obtained, add red dye, mix thoroughly, add yellow dye, and combine the total solids to 8% and 10%, respectively, and apply the under layer and the heat-sensitive layer. BACK) coated on the support coated with a wire bar to dry weight part 2g / m ² , and then hot-air-dried, superseded by a chronotype smoothness meter using a super calender to compress the film to have a smoothness of 500 to 1000 sec. A recording material was prepared. Example 1 is a case where solid content is 8%, and Example 2 is a case where solid content is 10%.

(Comparative Examples 1 to 3)

                                                         (Parts by weight)

 Material  Comparative Example 1  Comparative Example 2  Comparative Example 3  Aluminum hydroxide (25% liquid)  75  75  75  water  232  235  210  Polyvinyl alcohol (10% liquid)  250  250  150  Wet Strength Enhancer (10% Liquid)  60  60  60  Antifoaming agent (2% amount)  20  20  20  Lubricant (36% amount)  3  3  3  Red dye (20% liquid)  0  0.2  0.2  Yellow (YELLOW) dye (30% liquid)  0  0.8  0.8  Remarks  No dye input  The combination is the same as in Example 1, but when the RED dye and YELLOW dye at the same time  More aluminum hydroxide than polyvinyl alcohol (125%)

* Defoamer, wet strength improver, lubricant, dye and the like are the same as in the examples.

In Comparative Example 1, polyvinyl alcohol was first dissolved in water so as to have a solid content of 10%, and 70% of aluminum hydroxide, total polyvinyl alcohol and 70% of antifoaming agent were added, and the mixture was sufficiently mixed and dispersed with water to 10%. The dispersion is then milled through a milling machine to achieve an average particle diameter of 0.8-1.5 μm, and then mixed with the remaining 30% polyvinyl alcohol, 30% antifoaming agent, wet strength improver, and lubricant in order to disperse and disperse. . The antifoaming agent is more effective when dissolved in water separately. Same as Example, but no dye is added, Comparative Example 2 is the same combination as in Example 1, but in the state that the red (Yellow) dye and the dye (YELLOW) dye is not mixed completely before the addition When dye is added simultaneously. In Comparative Example 3, the ratio of polyvinyl alcohol and aluminum hydroxide is different from the example in which a large amount of aluminum hydroxide is added. The combination according to the above is mixed and dispersed using a milling machine. Other matters are carried out in the same manner as in the embodiment.

(Effect experiment)

The uniformity at the time of application | coating of the thermally sensitive recording material manufactured by each said Example and the comparative example by visual confirmation was confirmed, and abrasion resistance of the surface was carried out using CLOCK METER (Toyoseiki, Toyoseiki). The surface binding force is shown in Table 1 below through the tape (TAPE) test on the surface-bonding state of the thermal recording material, so that the surface printing process has the same background color as the Example and Comparative Example. In addition to Comparative Example 1, a printing process is performed.

Table-1

 Coating surface uniformity  Wear resistance  Surface binding  Surface Printing Process  Example 1  ◎  ◎  ◎  No need  Example 2  ◎  ◎  ◎  No need  Comparative Example 1  ◎  ×  ×  Required  Comparative Example 2  ×  ○  ◎  No need  Comparative Example 3  ◎  ×  ×  No need

◎: Very good ○: Good △: Normal ×: Bad

(Evaluation method)

1) Coating surface uniformity: Experiment to check the uniformity of the coated surface of the sample (SAMPLE) produced in Examples and Comparative Examples. Check the presence or absence of streaks, spots, etc. Confirm with

2) Abrasion Resistance: Examples 1 and 2 and Comparative Examples 1 to 3 were evaluated for wear resistance by using a CROCK METER. At this time, each sample (SAMPLE) is prepared to have a width of 3CM, length of 6CM and fixed to the clock meter (CROCK METER) and is an experiment to check the wear level of the friction surface by 30 reciprocating motion (see Fig. 1) .

3) Surface Adhesion: Using a cellophane tape (TAPE) was tested in three steps as follows (see Figure 2).

In the surface binding test, Examples 1 and 2 and Comparative Examples 2 and 3 do not need an additional printing process, but Comparative Example 1 requires an additional printing process to make a color on the background. Perform printing after U.V. printing. The cellophane tape is slowly peeled off from the top to the rear in about 180 ° in the first step, the next two steps are slowly peeled off in the upper 90 ° direction, and the third step is quickly removed in the rear 45 ° direction. In the surface binding force test, it is judged that the coating liquid on the coated surface does not fall or the coating liquid and the support are peeled off at the same time. If only the coating liquid is completely peeled off from the sample surface, the surface binding strength is judged to be bad.

Conventionally, polyvinyl alcohol, aluminum hydroxide, antifoaming agent, and the like as an over-liquid have been merely used to prevent sticking and protect the heat-sensitive layer. However, as the field of thermal paper has been widely developed, the color of the thermal paper is added, and thus the complexity of the process and the ideal matching with the thermal paper are required. Accordingly, the present invention has been made a useful invention that can be achieved without the wear of the thermal surface, excellent binding strength, and the desired color can be achieved even if repeated use several dozen times instead of one-time while maintaining the characteristics of the thermal paper. Incidentally, Comparative Example 1 is a case where the color dye is not added to the overcoating solution as a conventional formulation. In this case, a printing process for adding additional colors is required, and color by printing tends to be detached by repeated use, and consequently, contamination of the heat head (HEAD) is likely to occur. In addition, scratches on the thermal surface due to repeated use tend to cause contamination and color development of the thermal surface. Comparative Example 2 is the same as Example 1, but a case where the red (RED) dye and yellow (YELLOW) dye is added at the same time. In this case, a liquid agglomeration phenomenon occurs between the existing overcoating solution and the dye, and when applied on the support, staining occurs. Poor stability of the liquid makes it difficult to use for long periods of time. Comparative Example 3 is an experiment on the ratio between polyvinyl alcohol and aluminum hydroxide. The ratio of polyvinyl alcohol and aluminum hydroxide must be maintained at 1: 1 or more, and when the ratio of polyvinyl alcohol is low, the binding force worsens as in Comparative Example 3, resulting in a coating liquid.

Therefore, the present invention can be applied to various fields that require colored background printing, especially as a thermal recording material, and in particular, it has excellent binding power and can obtain the same quality as the initial one even in the field of repeated use several times. It is an invention useful for producing a product having excellent wear resistance.

Claims (5)

In a thermal recording material having a three-layer structure of an under layer, a thermal layer, and an over layer on a support, and having a back layer designed on the back side of the support, the coating liquid of the over layer designed on the thermal layer is poly 200 to 300 parts by weight of vinyl alcohol (10% liquid), 50 to 100 parts by weight of aluminum hydroxide (Al (OH) ₃ ) (15 to 30% liquid), 15 to 30 parts by weight of an antifoaming agent (2 to 5% liquid), wet 50 to 80 parts by weight of the intelligence enhancer (10 to 15% solution), 2 to 5 parts by weight of lubricant (36% solution) and 0.1 to 0.5 parts by weight of red dye (20% solution), an anionic color dye, and yellow (YELLOW) A dye-sensitized recording material composed of 0.6 to 1.2 parts by weight of dye (30% liquid), which is added with water to be 8 to 10% by solid content. The thermally sensitive recording material of claim 1, wherein the polyvinyl alcohol maintains an amount of one to one or more than aluminum hydroxide. The thermally sensitive recording material according to claim 1, wherein the dry adhesion amount of the overcoating solution is 2.0 to 5.0 g / m ² . In preparing the thermal recording material according to the composition of claim 1, the order of input of the raw materials is 70% of aluminum hydroxide, polyvinyl alcohol and 70% of the antifoaming agent, and the mixture is sufficiently mixed and dispersed so that the solid content is 10% with water. The dispersion is pulverized through a milling machine so that the average particle diameter is 0.8 to 1.5 μm, and the remaining 30% polyvinyl alcohol, 30% antifoaming agent, wet strength improver, and lubricant are added in order. A method of manufacturing a thermal recording material, characterized in that a color dye is added after mixing. 5. The method of claim 4, wherein the anionic colored dye is added as a method of adding one type of colored dye, after the other combination solution is combined, and finally, the two or more types are added after one type of dye is completely mixed. Method for producing a thermal recording material, characterized in that the remaining one type of dye.

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