Bicolor erasable thermal paper based on heat conduction aid and method for preparing the same

Abstract

The present application relates to the based on the heat conduction adjuvant two-color erasable thermal paper and preparation method thereof, relate to printing consumables technical field, two-color erasable thermal paper includes protective layer and thermal coating;The thermal coating includes red thermal coating and black thermal coating arranged from top to bottom in turn, the red thermal coating is provided with protective layer;The component of the protective layer and the red thermal coating includes heat conduction adjuvant, and the color temperature difference between the red thermal coating and the black thermal coating is greater than 20 DEG C.The heat conduction adjuvant is added to the protective layer and the thermal coating, realizes the cooperation of the protective layer and the thermal coating, the display of two colors, and the red and black superimposed color can be erased.

Description

Technical Field

[0001] This invention relates to the field of printing consumables technology, specifically to a two-color erasable thermal paper based on a thermally conductive additive and its preparation method. Background Technology

[0002] Currently, erasable information storage for identification cards utilizes thermal erasable technology, but its limited color options make it unsuitable for office use. Furthermore, two-color irreversible thermal paper, which can only be used once, leads to severe environmental pollution and resource waste. Therefore, developing erasable two-color thermal paper is of great significance.

[0003] There is relatively little research and development on two-color erasable thermal paper because the melting points of two-color thermal dyes are similar, making it difficult to achieve color layering. Therefore, this invention provides a two-color erasable thermal paper based on a thermally conductive additive and its preparation method. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a two-color erasable thermal paper based on a thermally conductive additive and its preparation method. The aim is to solve the problem of color overlap in two-color erasable thermal paper by designing the thermally conductive additive and controlling the coating thickness.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0006] Firstly, a two-color erasable thermal paper based on a thermally conductive additive, wherein the two-color erasable thermal paper includes a protective layer and a thermal coating; the thermal coating includes a red thermal coating and a black thermal coating arranged sequentially from top to bottom, and a protective layer (paper base, pre-coating, high melting point thermally sensitive layer, low melting point thermally sensitive layer, and protective layer) is disposed on the red thermal coating; the components of the protective layer and the red thermal coating include a thermally conductive additive, and the color development temperature difference between the red thermal coating and the black thermal coating is greater than 20°C.

[0007] The beneficial effects of this invention are: by adding thermally conductive additives to the protective layer and the thermal coating, the protective layer and the thermal coating work together to achieve dual-color display, with erasable red and black overlay.

[0008] Based on the above technical solution, the present invention can be further improved as follows.

[0009] Furthermore, the thermally conductive agent includes at least one of ZnO, Al2O3, and MgO.

[0010] The beneficial effect of adopting the above-mentioned further scheme is to improve the heat transfer effect in the protective layer and the red heat-sensitive layer.

[0011] Furthermore, the thermally conductive additive in the protective layer accounts for 15-20% of the total mass of the thermosensitive coating; the thermally conductive additive in the red thermosensitive coating accounts for 1wt% to 8wt% of the total mass of the thermosensitive coating.

[0012] The beneficial effects of adopting the above-mentioned further scheme are: the thermal conductivity rate of the protective layer and the rate of the red coloring layer gradually decrease, which is conducive to improving the heat utilization rate.

[0013] Furthermore, the thermally conductive additives in the protective layer are Al2O3 and MgO, with a mass ratio of Al2O3 to MgO of 2:1. Preferably, the thermally conductive additives in the protective layer account for 4wt% to 7wt% of the total mass of the thermosensitive coating. The thermally conductive additives in the red thermosensitive coating are ZnO and Al2O3, with a mass ratio of ZnO to Al2O3 of 4:1. Preferably, the thermally conductive additives in the red thermosensitive coating account for 3wt% to 5wt% of the total mass of the thermosensitive coating.

[0014] The advantage of adopting the above-mentioned further solutions is that it reduces costs while ensuring thermal conductivity.

[0015] Furthermore, the thickness of the protective layer is not less than 4 μm; the thickness of the red thermosensitive coating is not more than 6 μm; and the thickness of the black thermosensitive coating is not less than 7 μm.

[0016] The beneficial effect of adopting the above-mentioned further solution is that the present invention proposes to achieve erasable red and black overlay by controlling the thickness of the protective layer and the thermal coating in a coordinated manner.

[0017] Furthermore, the thickness of the protective layer is 5-7 μm; the thickness of the red thermosensitive coating is 3-5 μm; and the thickness of the black thermosensitive coating is 7-9 μm.

[0018] The beneficial effect of adopting the above-mentioned further solutions is that it helps control costs.

[0019] Furthermore, the protective layer comprises the following specific components by weight: 10-15 parts of thermally conductive agent, 2-5 parts of UV-resistant agent, 2-8 parts of lubricant, and 70-80 parts of adhesive resin;

[0020] The red thermosensitive coating comprises the following components by weight: 3-8 parts of thermally conductive agent, 10-15 parts of color developer, 3-8 parts of thermosensitive dye, 20-30 parts of adhesive resin, and 3-10 parts of filler;

[0021] The black thermosensitive coating comprises the following components by weight: 15-20 parts of color developer, 3-8 parts of thermosensitive dye, 20-30 parts of adhesive resin, and 3-8 parts of filler.

[0022] Preferably, in the protective layer, the UV-resistant additive includes at least one selected from salicylate esters, benzophenones, benzotriazoles, substituted acrylonitrile esters, and triazine esters; the lubricant includes at least one selected from zinc stearate, mineral lubricants (such as machine oil), silicone oil, fatty acid amides, oleic acid, polyesters, synthetic esters, and carboxylic acids; the adhesive includes at least one selected from PVA, polyacrylates, and polyurethanes; and the thermally conductive additive is at least one selected from zinc oxide, MgO, and Al2O3.

[0023] In the red thermosensitive coating, the color developer includes alkylphenol, for example... In the formula, P = 12~37; the thermosensitive dye includes at least one of scarlet, peach, and orange, with the following structural formula: The adhesive comprises at least one of polyvinyl alcohol, polyacrylate, and polyurethane; the filler comprises at least one of calcium carbonate and talc.

[0024] In the black thermosensitive coating, the color developer and the red thermosensitive coating have the same type and amount of color developer; the thermosensitive dye includes at least one of ODB2, S2O5, and B15; the structural formula is as follows:

[0025] ;

[0026] The adhesive resin includes at least one of polyvinyl alcohol, polyacrylate, and polyurethane; the filler includes at least one of calcium carbonate and talc.

[0027] Furthermore, the two-color erasable thermal paper also includes a base coating and a substrate, wherein the base coating is disposed under the black thermal coating and the base coating is disposed on the substrate;

[0028] The base coating comprises the following components by weight: 40-60 parts of adhesive PVA resin, 20-40 parts of heat-insulating filler glass microspheres, and 5-20 parts of brightening agent titanium dioxide.

[0029] Preferably, in the base coating, the adhesive resin is 45-55 parts of PVA resin; the heat insulation filler is 25-35 parts of glass microspheres; and the whitening agent is 10-15 parts of TiO2.

[0030] The substrate is paper-based, preferably PVC paperboard.

[0031] Furthermore, the thickness of the base coating is 1~3µm; the thickness of the substrate is 100~140µm.

[0032] Secondly, the preparation method of two-color erasable thermal paper based on thermally conductive additives includes the following steps:

[0033] S1: Prepare the components of the base coating into a coating liquid, apply the coating liquid to the substrate, and dry it to obtain the base coating on the substrate;

[0034] S2: Prepare a coating liquid for red thermosensitive coating by taking the components of red thermosensitive coating; prepare a coating liquid for black thermosensitive coating by taking the components of black thermosensitive coating; coat the coating liquid for red thermosensitive coating and the coating liquid for black thermosensitive coating onto the base coating in sequence, and dry to obtain thermosensitive coating.

[0035] S3: Prepare the components of the protective layer into a coating liquid for the protective layer, coat it onto the heat-sensitive coating, and dry it to obtain the protective layer;

[0036] S4: The substrate, base coating, thermal coating and protective layer are composited by hot pressing process to obtain a two-color erasable thermal paper based on thermally conductive additive. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the two-color erasable thermal paper of the present invention. Figure I ;

[0038] Figure 2 This is a schematic diagram of the two-color erasable thermal paper of the present invention. Figure II . Detailed Implementation

[0039] The principles and features of this invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they should be performed according to the techniques or conditions described in the literature in this field, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.

[0040] Compare with Example 1:

[0041] This embodiment relates to a two-color erasable thermal paper based on a thermally conductive additive. The two-color erasable thermal paper, from top to bottom, comprises a protective layer, a red thermal coating layer, a black thermal coating layer, a base coating layer, and a substrate. Figure 1 and 2 );

[0042] The protective layer comprises the following components in parts by weight: 40 parts zinc oxide, UV stabilizer...

[0043] The mixture consists of 5 parts benzotriazole, 3 parts talc (solid lubricant), and 75 parts PVA adhesive resin; the thickness is controlled at 3 μm.

[0044] The red heat-sensitive coating comprises the following components in parts by weight: thermally conductive aid, zinc oxide 5

[0045] The mixture consists of 12 parts color developer, 4 parts thermosensitive dye (pink), 15 parts PVA adhesive, and 6 parts calcium carbonate filler, with a thickness controlled at 6 μm; the color developer is... In the formula, P = 12~37;

[0046] The black thermal coating comprises the following components in parts by weight: 12 parts color developer, thermal...

[0047] The mixture consists of 3 parts of sensitive dye (S205), 15 parts of PVA adhesive resin, and 5 parts of calcium carbonate filler, with a thickness controlled at 6 μm; the color developer is... In the formula, P = 12~37;

[0048] The base coating comprises the following components by weight: 75 parts PVA adhesive resin, 17 parts glass microspheres, and 8 parts TiO2; the thickness is controlled at 2 μm.

[0049] The preparation method of the two-color thermal erasable paper based on the color developer structure design involved in this embodiment includes the following steps:

[0050] S1: Prepare the components of the base coating into a coating liquid, apply the coating liquid to the substrate, and dry it to obtain the base coating on the substrate;

[0051] S2: Prepare a coating liquid for red thermosensitive coating by taking the components of red thermosensitive coating; prepare a coating liquid for black thermosensitive coating by taking the components of black thermosensitive coating; coat the coating liquid for red thermosensitive coating and the coating liquid for black thermosensitive coating onto the base coating in sequence, and dry to obtain thermosensitive coating.

[0052] S3: Prepare the components of the protective layer into a coating liquid for the protective layer, coat it onto the heat-sensitive coating, and dry it to obtain the protective layer;

[0053] S4: The substrate, base coating, thermal coating and protective layer are composited by hot pressing process to obtain a two-color thermal erasable paper based on the color developer structure design.

[0054] Compare with Example 2:

[0055] In this embodiment, the red thermosensitive coating is controlled at 2~3µm; the black thermosensitive coating is controlled at 4~6µm, and the other parameters are the same as in Example 1.

[0056] Compare with Example 3:

[0057] In this embodiment, the thermal conductive agent in the protective layer is increased to 6 parts, and the rest is the same as in Embodiment 1.

[0058] Compare with Example 4:

[0059] In this embodiment, the thermal conductive agent in the protective layer is increased to 6 parts; the thermal conductive agent in the red thermosensitive coating is increased to 6 parts; other aspects are the same as in Embodiment 1.

[0060] Compare with Example 5:

[0061] Based on Example 1, without the addition of a thermally conductive additive, only a mixed color will be displayed.

[0062] Compare with Example 6:

[0063] Based on Example 1, if only a thermally conductive agent is added to the protective layer, only red and mixed colors will be visible.

[0064] Example 1:

[0065] In this implementation, the protective layer is controlled at 4~5um, and other aspects are the same as in control example 1.

[0066] Experimental example:

[0067] Erasing method: Print on a Zebra printer with a red print density of 15 and a black print density of 30.

[0068] Erasure efficiency: (Erased color density - Base color density) / (Printed color density - Base color density) * 100%.

[0069] The resulting color densities before and after erasing are shown in Table 1 below:

[0070] Table 1

[0071]

[0072] In summary, by adding thermally conductive additives to the protective layer and the thermal coating, the protective layer and the thermal coating work together to achieve a dual-color display with erasable red and black overlay.

[0073] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0074] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A two-color erasable thermal paper based on a thermally conductive additive, characterized in that, The dual-color erasable thermal paper includes a protective layer and a thermal coating; the thermal coating includes a black thermal coating and a red thermal coating arranged sequentially from top to bottom, and a protective layer is disposed on the black thermal coating; the components of the protective layer and the red thermal coating include a thermally conductive additive, and the color development temperature difference between the red thermal coating and the black thermal coating is greater than 20°C; The thermally conductive additive in the protective layer accounts for 15-50% of the total mass of the thermosensitive coating; the thermally conductive additive in the red thermosensitive coating accounts for 1wt%-8wt% of the total mass of the thermosensitive coating. The thermally conductive additives in the protective layer are Al2O3 and MgO, with a mass ratio of Al2O3 to MgO of 2:1; the thermally conductive additives in the red thermosensitive coating are ZnO and Al2O3, with a mass ratio of ZnO to Al2O3 of 4:

1. The thickness of the protective layer is 5-7 μm; the thickness of the red thermosensitive coating is 3-5 μm; and the thickness of the black thermosensitive coating is 7-9 μm.

2. The dual-color erasable thermal paper based on a thermally conductive additive according to claim 1, characterized in that, The protective layer comprises the following components in parts by weight: 15-50 parts of thermally conductive agent, 1-10 parts of UV-resistant agent, 1-5 parts of lubricant, and 70-80 parts of adhesive resin. The red thermosensitive coating comprises the following components by weight: 1-8 parts of thermally conductive agent, 10-15 parts of color developer, 2-5 parts of thermosensitive dye, 10-20 parts of adhesive, and 3-8 parts of filler; The black thermosensitive coating comprises the following components by weight: 10-15 parts of color developer, 2-5 parts of thermosensitive dye, 10-20 parts of adhesive, and 4-6 parts of filler.

3. The dual-color erasable thermal paper based on a thermally conductive additive according to claim 1, characterized in that, The two-color erasable thermal paper also includes a base coating and a substrate, wherein the base coating is disposed under the black thermal coating and the base coating is disposed on the substrate; The base coating comprises the following components by weight: 20-60 parts adhesive resin, 10-15 parts thermal insulation filler, and 3-5 parts whitening agent.

4. The dual-color erasable thermal paper based on a thermally conductive additive according to claim 3, characterized in that, The thickness of the base coating is 1~3μm; the thickness of the substrate is 100~150μm.

5. A method for preparing a two-color erasable thermal paper based on a thermally conductive additive according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1: Prepare the components of the base coating into a coating liquid, apply the coating liquid to the substrate, and dry it to obtain the base coating on the substrate; S2: Prepare a coating liquid for red thermosensitive coating by taking the components of red thermosensitive coating; prepare a coating liquid for black thermosensitive coating by taking the components of black thermosensitive coating; coat the coating liquid for red thermosensitive coating and the coating liquid for black thermosensitive coating onto the base coating in sequence, and dry to obtain thermosensitive coating. S3: Prepare the components of the protective layer into a coating liquid for the protective layer, coat it onto the heat-sensitive coating, and dry it to obtain the protective layer; S4: The substrate, base coating, thermal coating and protective layer are composited by hot pressing process to obtain a two-color erasable thermal paper based on thermally conductive additive.

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