Thermal transfer printing receiving sheet capable of transferring high-color-concentration image and preparation method thereof

Abstract

The invention relates to a thermal transfer receiving sheet capable of transferring a high-color-concentration image and a preparation method of the thermal transfer receiving sheet, and relates to the technical field of thermal transfer. The heat transfer printing receiving sheet comprises a receiving layer, and the receiving layer is prepared from the following raw materials in parts by weight: 30 to 60 parts of vinyl chloride-vinyl acetate resin, 3 to 10 parts of polyvinyl butyral resin, 0.1 to 5 parts of poly-alpha olefin and 0.1 to 1 part of release agent. According to the heat transfer printing receiving sheet formed by the raw materials of the receiving layer, the color saturation of an image on the heat transfer printing receiving sheet can be obviously improved, the heat transfer printing receiving sheet has high demolding performance, and the problems of adhesion, fading and other transfer printing defects occurring in transfer printing are solved.

Description

Technical Field

[0001] The invention relates to the technical field of thermal transfer, in particular to a thermal transfer receiving sheet capable of transferring high color density images and a preparation method thereof. Background Art

[0002] Among the existing printing technologies, the thermal sublimation transfer method is superior in that it can freely adjust the image tone concentration, and has excellent intermediate gradation and grayscale reproducibility, so that it can achieve an imaging effect comparable to silver halide photographic paper and form a high-quality image product. In the thermal sublimation printing process, a thermal transfer sheet with a dye is overlapped with a thermal transfer receiving sheet with a receiving layer, and the thermal transfer sheet is heated by the print head of the thermal transfer printer, so that the dye in the dye layer sublimates into the receiving layer on the thermal transfer receiving sheet to form an imprint, thereby forming a colorful image.

[0003] In the process of forming a colorful image, the thermal transfer sheet is in contact with the thermal transfer receiving sheet. During the heating process, the resin in the dye layer of the thermal transfer sheet melts / deforms, which may cause adhesion with the receiving layer resin on the thermal transfer receiving sheet, resulting in adhesion between the thermal transfer sheet and the thermal transfer receiving sheet, discoloration, and other problems during printing, causing serious image defects.

[0004] At present, the commonly used method is to add lubricant in the receiving layer of the thermal transfer receiving sheet to solve the above-mentioned problem, usually select silicone resin, silicone modified resin, wax or other auxiliary agents with demoulding and lubricating effect. Wherein silicone is widely used because it has good heat resistance and wear resistance. But the affinity of silicone resin dye is weak, and then the saturation of the transfer image will be negatively affected. In view of this, the invention provides a kind of thermal transfer receiving sheet and preparation method thereof that can transfer high color density image. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a thermal transfer receiving sheet capable of transferring high color density images and a preparation method thereof. The purpose is to provide a thermal transfer receiving sheet capable of avoiding adhesion between thermal transfer receiving sheets and thermal transfer sheets and having high image saturation and a preparation method thereof.

[0006] The technical solution of the present invention to solve the above technical problems is as follows:

[0007] In the first aspect, a thermal transfer receiving sheet capable of transferring high color density images is provided, wherein the thermal transfer receiving sheet comprises a receiving layer, and the receiving layer comprises the following raw materials in parts by weight: 30-60 parts of vinyl chloride vinyl acetate resin, 3-10 parts of polyvinyl butyral resin, 0.1-5 parts of polyalphaolefin, and 0.1-1 part of a release agent.

[0008] The beneficial effects of the present invention are:

[0009] (1) The receiving layer is used as a layer for receiving thermal sublimation dyes and maintaining the formed image; the resin materials (vinyl chloride vinyl acetate resin and polyvinyl butyral resin) used are transparent; the thermal transfer receiving sheet formed by the raw materials of the above-mentioned receiving layer can significantly improve the color saturation of the image on the receiving sheet, and has a high demoulding performance, reducing the transfer defects such as adhesion and fading caused by transfer; wherein the vinyl chloride vinyl acetate resin and polyvinyl butyral resin in the present invention can significantly improve the saturation of the transfer pattern, and at the same time can reduce the transfer defects such as adhesion and fading caused by the thermal transfer sheet and the receiving layer resin, as well as the transferability to the protective layer of the receiving layer; the release agent in the receiving layer of the thermal transfer receiving sheet can prevent the fading problem caused by poor demoulding under high transfer concentration, and the release agent and polyalphaolefin work together to further improve the color saturation of the transferred image and reduce the transfer defect problem.

[0010] (2) The polyalphaolefin in the receiving layer of the present invention is preferably 0.1-5 parts by weight, which can ensure the transparency of the receiving layer and improve the demoulding performance of the thermal transfer sheet under high color concentration, further improve the color saturation of the transferred pattern, and reduce the adhesion and fading problems of the thermal transfer sheet; polyalphaolefin is different from solid waxes, surfactants, silicone oils, silicone resins and other release agents. Its addition has a certain promoting effect on the migration of dyes during the transfer process and can ensure excellent demoulding performance. However, excessive addition of polyalphaolefin will cause a large amount of demoulding agent to exist on the surface of the receiving sheet, resulting in poor adhesion between it and the protective layer, which will have a greater negative impact on the protective effect of the protective layer and greatly reduce the environmental resistance of the thermal transfer receiving sheet.

[0011] Based on the above technical solution, the present invention can also be improved as follows.

[0012] Furthermore, the release agent includes at least one of solid waxes, surfactants, silicone oil, and silicone resins.

[0013] The beneficial effect of adopting the above further solution is that the above release agent can significantly improve the demoulding property of the transfer and prevent the problems of adhesion and discoloration.

[0014] Furthermore, the wax may be polyethylene wax, polyamide wax or polytetrafluoroethylene wax, etc.; the surfactant may be a phosphate surfactant, a fluorine-based surfactant, etc.; the silicone oil is preferably a modified silicone oil; as the modified silicone oil, it may be fluorine-modified silicone, amino-modified silicone, epoxy-modified silicone, aralkyl-modified silicone, epoxy-aralkyl-modified silicone, alcohol-modified silicone, vinyl-modified silicone and urethane-modified silicone, etc.; polyether-modified silicone is particularly preferred.

[0015] Furthermore, the receiving layer also includes additives; the additives include at least one of plasticizers, filling materials, UV stabilizing materials, coloring inhibition materials, surfactants, fluorescent whitening materials, matting materials, deodorizing materials, flame retardant materials, weather resistant materials, antistatic materials, yarn friction reducing materials, sliding materials, antioxidant materials, ion exchange materials, dispersing materials, UV absorbing materials, and coloring materials.

[0016] Furthermore, the thickness of the receiving layer is 0.5 μm-20 μm, preferably 1.0 μm-10 μm.

[0017] The beneficial effects of adopting the above further embodiment are: the above-mentioned thickness of the receiving layer can further improve the density of the image formed on the receiving layer and suppress the concave curling of the thermal transfer receiving sheet.

[0018] Furthermore, the thermal transfer receiving sheet also includes a primer layer, a front substrate and a back substrate; the primer layer is arranged on one side of the receiving layer, and the front substrate and the back substrate are arranged on the primer layer in sequence.

[0019] The beneficial effect of adopting the above further scheme is that the thermal transfer receiving sheet of the present invention has a primer layer between the front substrate and the receiving layer, which can improve the adhesion between the layers and produce printed objects with high color saturation.

[0020] Further, the primer layer comprises the following raw materials in parts by weight: 15-25 parts of a main resin material, 2.5-8 parts of a polyvinyl butyral resin;

[0021] The front substrate is a resin film;

[0022] The back substrate includes at least one of a paper substrate and a resin film.

[0023] Further, the main resin material includes at least one of polyester, polyurethane, polycarbonate, (meth)acrylic resin, styrene resin, vinyl resin and cellulose resin;

[0024] The resin film comprises at least one of polyester, polyamide, polyolefin, vinyl resin, (meth) acrylic resin, imide resin, cellulose resin, styrene resin, polycarbonate, and ionomer resin;

[0025] In addition, a film formed by laminating two or more of the above-mentioned resin films can also be used as a substrate; the laminate can be produced by utilizing a dry lamination method, a wet lamination method, or an extrusion method. A white opaque film formed by adding a white pigment or a filler to a resin film, or a film having a void inside can be used. Among the above, coated paper and uncoated paper are preferred from the aspects of transportability and mechanical strength in a printer. In addition, a material formed by laminating the above-mentioned paper substrate or resin film can be used.

[0026] The paper substrate includes at least one of capacitor paper, glassine paper, sulfate paper, synthetic paper, high-grade paper, art paper, coated paper, uncoated paper, high-gloss printing paper, wallpaper, cellulose fiber paper, synthetic resin-filled paper, backing paper, and impregnated paper (synthetic resin impregnated paper, emulsion impregnated paper, synthetic rubber emulsion impregnated paper).

[0027] Further, the polyester includes polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), poly(1,4-cyclohexanedimethylene terephthalate), terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer, etc.; the polyamide includes nylon 6, nylon 6,6, etc.; the polyolefin includes polyethylene (PE), polypropylene (PP), polymethylpentene, etc.; the vinyl resin includes polyvinyl chloride, polyvinyl alcohol (PVA), polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyvinyl pyrrolidone (PVP), etc.; the (meth) acrylic resin includes polyacrylate and polymethacrylate, etc.; the imide resin includes polyimide, polyetherimide, etc.; the cellulose resin includes cellophane, cellulose acetate, cellulose nitrate, cellulose acetate-propionate (CAP) and cellulose acetate butyrate (CAB), etc.; the styrene resin includes polystyrene (PS), etc.;

[0028] Among the above resin materials, polypropylene resin is preferred in terms of mechanical strength and glossiness, and pearlescent PP film containing inorganic particles is further preferred. This can prevent the problem of insufficient color saturation of the image caused by the rapid loss of temperature of the print head of the thermal transfer printer.

[0029] Further, the thickness of the primer layer is 0.1 μm-3.0 μm; the thickness of the front substrate is 5 μm-150 μm, preferably 7 μm-75 μm, more preferably 10 μm-60 μm, and particularly preferably 10 μm-48 μm;

[0030] The thickness of the back substrate is 50 μm to 300 μm, and preferably 90 μm to 165 μm from the viewpoint of curl suppression.

[0031] The beneficial effect of adopting the above further solution is that the thickness of the above primer layer can further improve the curling suppression property.

[0032] In the second aspect, a method for preparing a thermal transfer receiving sheet capable of transferring high color concentration images comprises the following steps: mixing the raw materials of the receiving layer and the base coat with solvents respectively to prepare a receiving layer coating liquid and a base coat coating liquid, applying the base coat coating liquid and the receiving layer coating liquid successively to one side of the front substrate, and drying to obtain a thermal transfer receiving sheet.

[0033] Furthermore, the coating method includes at least one of a roll coating method, a reverse roll coating method, a gravure coating method, a reverse gravure coating method, and a bar coating method.

[0034] The third aspect provides a printed matter, wherein the printed matter is made using the above-mentioned thermal transfer receiving sheet, and an image is formed on or inside the receiving layer. The printed matter has a protective layer on the receiving layer formed with the image. In addition, the protective layer may also be partially located on the receiving layer.

[0035] The content of the resin material in the protective layer is not particularly limited. From the perspective of image friction resistance and storage stability, it is preferably 30% to 90%; the protective layer may include the above-mentioned additives; the thickness of the protective layer is preferably 0.5μm-10μm, more preferably 1μm-5μm, and particularly preferably 2μm-4.5μm. This can improve the color saturation of the printed image, and further improve the durability and storage stability of the printed image. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic structural diagram of the thermal transfer receiving sheet of the present invention. DETAILED DESCRIPTION

[0037] The principles and features of the present invention are described below, and the examples are only used to explain the present invention and are not used to limit the scope of the present invention. If no specific technology or conditions are specified in the embodiments, the technology or conditions described in the literature in this field or the product instructions are used. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased through regular channels.

[0038] Example 1

[0039] A thermal transfer receiving sheet capable of transferring a high color density image, characterized in that the thermal transfer receiving sheet comprises a receiving layer, a primer layer, a front substrate and a back substrate; the primer layer is arranged on one side of the receiving layer, and the front substrate and the back substrate (such as Figure 1 ).

[0040] The present embodiment provides a method for preparing a thermal transfer receiving sheet capable of transferring a high color density image, comprising the following steps:

[0041] (1) preparing a 50 μm thick PP film and coating the following composition of the primer coating liquid on the front side of the PP film and drying it to obtain a 0.8 μm primer layer;

[0042] Primer coating liquid: 20 parts by mass of polyester resin, 5 parts of polyvinyl butyral resin, 45 parts of toluene, and 45 parts of methyl ethyl ketone.

[0043] (2) coating the primer layer with the following composition for forming a receiving layer and drying it to form a receiving layer with a thickness of 3 μm;

[0044] Receiving layer coating liquid: 30 parts of vinyl chloride vinyl acetate resin, 10 parts of polyvinyl butyral resin, 0.5 parts of polyalphaolefin, 5 parts of silicone oil, 50 parts of toluene, and 50 parts of butanone.

[0045] (3) Adhesive layer coating liquid: 20 parts of polyol resin, 5 parts of isocyanate compound, and 80 parts of butyl acetate.

[0046] The adhesive layer coating liquid of the above composition was applied to the opposite side of the PP film and dried to form an adhesive layer with a thickness of 2.4 μm. A thermal transfer receiving sheet was obtained by laminating coated paper A (manufactured by Nippon Paper Industries, Ltd., Yutrilo (registered trademark) 157, thickness 130 μm) as the back substrate with the adhesive layer.

[0047] Example 2

[0048] Compared with Example 1, the receiving layer coating liquid in Example 1 is replaced with: 30 parts of vinyl chloride vinyl acetate resin, 10 parts of polyvinyl butyral resin, 5 parts of polyalphaolefin, 0.5 parts of silicone oil, 50 parts of toluene, and 50 parts of butanone.

[0049] Example 3

[0050] Compared with Example 1, the receiving layer coating liquid in Example 1 is replaced with: 50 parts of vinyl chloride vinyl acetate resin, 10 parts of polyvinyl butyral resin, 5 parts of polyalphaolefin, 1.5 parts of silicone oil, 50 parts of toluene, and 50 parts of butanone.

[0051] Comparative Example 1: No addition of polyalphaolefin

[0052] Compared with Example 1, the receiving layer coating liquid in Example 1 is changed to: 30 parts of vinyl chloride vinyl acetate resin, 10 parts of polyvinyl butyral resin, 5 parts of silicone oil, 50 parts of toluene, and 50 parts of butanone.

[0053] Comparative Example 2: Adding a large amount of polyalphaolefin

[0054] Compared with Example 1, the receiving layer coating liquid in Example 1 is replaced with: 30 parts of vinyl chloride vinyl acetate resin, 10 parts of polyvinyl butyral resin, 8 parts of polyalphaolefin, 0.5 parts of silicone oil, 50 parts of toluene, and 50 parts of butanone.

[0055] Comparative Example 3

[0056] Compared with Example 3, the coating liquid of Example 3 was used, but no primer layer was applied.

[0057] Comparative Example 4

[0058] Compared with Example 1, the receiving layer coating liquid in Example 1 is replaced with: 30 parts of vinyl chloride vinyl acetate resin, 10 parts of polyvinyl butyral resin, 50 parts of toluene, and 50 parts of butanone.

[0059] Comparative Example 5

[0060] Compared with Example 1, the receiving layer coating liquid in Example 1 is replaced with: 30 parts of vinyl chloride vinyl acetate resin, 10 parts of polyvinyl butyral resin, 6 parts of silicone, 50 parts of toluene, and 50 parts of butanone.

[0061] Comparative Example 6

[0062] Compared with Example 1, the coating liquid of the receiving layer in Example 1 was changed to: 30 parts of vinyl chloride vinyl acetate resin, 10 parts of polyvinyl butyral resin, 6 parts of silicone, 50 parts of toluene, and 50 parts of butanone. The coating thickness was 5 μm.

[0063] Test example

[0064] (1) Image color saturation evaluation

[0065] Prepare the thermal transfer image receiving sheet of the embodiment and the comparative example, the above-mentioned sublimation type thermal transfer printer, and the original ribbon for the printer, and print a black solid image under 20°C and 30%RH environment to obtain a printed product. It should be noted that the printer is set to gloss mode, and the image grayscale of the black solid image is 0 / 255 level. The image density of the printed product manufactured as described above is measured using an optical densitometer (manufactured by X-Rite, i1Pro2), and evaluated based on the following evaluation criteria. The evaluation results are shown in Table 1. It should be noted that the measurement was carried out under the following conditions, and the evaluation results are shown in Table 1.

[0066] The measurement conditions are as follows:

[0067] Density state: state A

[0068] Measurement lighting conditions: M0 (ISO 13655-2009)

[0069] The evaluation criteria are as follows:

[0070] A: OD value is 2.05 or more.

[0071] B: OD value is 1.80 or more and less than 2.05.

[0072] C: OD value is 1.50 or more and less than 1.80.

[0073] D: OD value is 1.30 or more and less than 1.50.

[0074] (2) Evaluation of transfer release properties

[0075] The printed matter produced in the image density evaluation was visually observed and evaluated based on the following evaluation criteria. The evaluation results are shown in Table 1.

[0076] The evaluation criteria are as follows:

[0077] A: There is no abnormal sound during printing and the transferred pattern has no color fading defects.

[0078] B: There is a slight abnormal sound during the transfer process, and the transferred pattern has no color fading defects.

[0079] C: There is a slight abnormal noise during the transfer process, and the transferred pattern has a small amount of discoloration defects.

[0080] D: There is a loud / slight abnormal noise during the transfer process, and the transferred pattern has serious discoloration defects.

[0081] Performance test plan: Use DNP DS620 thermal sublimation printer for printing test, use DNP DS620 original ribbon, and perform printing and color saturation test.

[0082] Table 1 Performance comparison of the embodiments

[0083] Example 1 Example 2 Example 3 Saturation A B A Release performance B B A

[0084] Table 2 Comparative performance comparison table

[0085] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Saturation C D C B C B Release performance D B D D C C

[0086] In summary, the present invention adopts the above-mentioned receiving layer raw materials to form a thermal transfer receiving sheet, which can significantly improve the color saturation of the image on the thermal transfer receiving sheet, and has a high demoulding performance, reducing the transfer defects such as adhesion and fading caused by transfer; wherein, the vinyl chloride vinyl acetate resin and polyvinyl butyral resin in the present invention can significantly improve the saturation of the transfer pattern, can reduce the transfer defects such as adhesion and fading caused by the thermal transfer sheet and the receiving layer resin, and the transferability to the protective layer of the receiving layer; the release agent in the receiving layer of the thermal transfer receiving sheet can prevent the fading problem caused by poor demoulding under high transfer concentration, and the release agent and poly-alpha-olefin work together to further improve the color saturation of the transfer image while reducing the transfer defect problem.

[0087] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0088] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A thermal transfer receiving sheet capable of transferring a high color density image, characterized in that: The thermal transfer receiving sheet comprises a receiving layer, and the receiving layer comprises the following raw materials in parts by weight: 30-60 parts of vinyl chloride vinyl acetate resin, 3-10 parts of polyvinyl butyral resin, 0.1-5 parts of polyalphaolefin, and 0.1-1 part of release agent.

2. A thermal transfer receiving sheet capable of transferring a high color density image according to claim 1, characterized in that: The release agent includes at least one of solid waxes, surfactants, silicone oil and silicone resin.

3. A thermal transfer receiving sheet capable of transferring a high color density image according to claim 1, characterized in that: The receiving layer also includes additives; the additives include at least one of plasticizers, fillers, UV stabilizing materials, coloring inhibitors, surfactants, fluorescent whitening materials, matting materials, deodorizing materials, flame retardants, weather resistant materials, antistatic materials, yarn friction reducing materials, sliding materials, antioxidants, ion exchange materials, dispersing materials, UV absorbing materials, and coloring materials.

4. A thermal transfer receiving sheet capable of transferring a high color density image according to claim 1, characterized in that: The thickness of the receiving layer is 0.5 μm-20 μm.

5. A thermal transfer receiving sheet capable of transferring a high color density image according to claim 1, characterized in that: The thermal transfer receiving sheet further comprises a primer layer, a front substrate and a back substrate; the primer layer is arranged on one side of the receiving layer, and the front substrate and the back substrate are arranged on the primer layer in sequence.

6. A thermal transfer receiving sheet capable of transferring a high color density image according to claim 5, characterized in that: The primer layer comprises the following raw materials in parts by weight: 15-25 parts of a main resin material, 2.5-8 parts of a polyvinyl butyral resin; The front substrate is a resin film; The back substrate includes at least one of a paper substrate and a resin film.

7. A thermal transfer receiving sheet capable of transferring a high color density image according to claim 6, characterized in that: The main resin material includes at least one of polyester, polyurethane, polycarbonate, (meth)acrylic resin, styrene resin, vinyl resin and cellulose resin; The resin film comprises at least one of polyester, polyamide, polyolefin, vinyl resin, (meth) acrylic resin, imide resin, cellulose resin, styrene resin, polycarbonate, and ionomer resin; The paper substrate includes at least one of capacitor paper, glass paper, sulfate paper, synthetic paper, high-grade paper, art paper, coated paper, uncoated paper, high-gloss printing paper, wallpaper, cellulose fiber paper, synthetic resin-filled paper, backing paper, and impregnated paper.

8. A thermal transfer receiving sheet capable of transferring a high color density image according to claim 5, characterized in that: The thickness of the primer layer is 0.1 μm-3.0 μm; the thickness of the front substrate is 5 μm-150 μm; and the thickness of the back substrate is 50 μm-300 μm.

9. A method for preparing a thermal transfer receiving sheet capable of transferring a high color density image according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: mixing the raw materials of the receiving layer and the base coating layer with solvents respectively to prepare a receiving layer coating liquid and a base coating liquid, coating the base coating liquid and the receiving layer coating liquid on one side of the front substrate in sequence, and drying to obtain a thermal transfer receiving sheet.

10. A method for preparing a thermal transfer receiving sheet capable of transferring a high color density image according to claim 9, characterized in that: The coating method includes at least one of a roller coating method, a reverse roller coating method, a gravure coating method, a reverse gravure coating method, and a rod coating method.

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