A heat transfer receiving sheet and a method for preparing the same

Abstract

The present application relates to a kind of heat transfer printing receiving sheet and its preparation method, belong to soft mark printing technical field.Heat transfer printing receiving sheet, including from top to bottom sequentially arranged printing layer, heat insulation layer, substrate and back coating layer;The back coating layer includes the following weight parts of raw materials: first resin 13-16 parts, filler 2-3 parts, polyethylene glycol 0.1-0.5 parts, lithium chloride 0.01-0.05 parts;The heat insulation layer is by including the following weight parts of raw materials: binder 9-11 parts, hollow particle 4-7 parts;The printing layer includes the following weight parts of raw materials: second resin 19-22 parts, aromatic hydrocarbon modified polysiloxane 0.1-1 parts, polyethylene glycol 0.1-1 parts, polyisocyanate curing agent 0.1-1 parts.The present application also discloses the preparation method of above-mentioned heat transfer printing receiving sheet, the heat transfer printing receiving sheet of the present application can prevent heat transfer printing sheet and heat transfer printing sheet hot melt connection even in the case of printing speed high speed, and with heat transfer printing sheet's demouldability also good, aging resistance and can improve the optical density of print image.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal transfer consumables, and in particular to a thermal transfer receiving sheet and a preparation method thereof. Background Art

[0002] In recent years, sublimation transfer recording has garnered significant attention. Using a heating medium such as a thermal printhead or laser to heat an ink ribbon containing a sublimable dye formed on a support such as polyester film, the resulting image is formed on a thermal transfer receiving sheet. Thermal sublimation printing technology is used as an information recording medium in various fields. This method enables the creation of full-color gradation images in a very short time, producing both halftone and full-color images with excellent reproducibility and gradation, resulting in high-quality images comparable to silver halide photographs.

[0003] Dye-sublimation printing offers excellent grayscale quality because the amount of dye transferred can be controlled on a dot-by-dot basis based on the amount of energy applied. However, unlike conventional printing inks, the resulting images are made from low-molecular-weight dyes rather than pigments, resulting in poor lightfastness, weatherability, abrasion resistance, and durability. Furthermore, the recent increase in print speeds in dye-sublimation printers has led to higher temperatures applied to the thermal head, causing thermal fusing of the thermal transfer sheet and the dye-sublimation ribbon. To address this fusing issue, existing technologies have increased the softening point of the resin that makes up the receiving layer, but this results in a decrease in the optical density of the resulting pattern. Summary of the Invention

[0004] To address the above-mentioned technical problems, the present invention provides a thermal transfer receiving sheet and a method for preparing the same. The thermal transfer receiving sheet comprises a heat-insulating layer having both heat-insulating and cushioning properties to prevent the substrate from being melted while also exhibiting good adhesion. A sublimation ribbon having a dye layer is used to form an image on the printing layer through sublimation. Even at high printing speeds, the thermal transfer sheet and the sublimation ribbon are prevented from thermally fusing, exhibit good demolding properties from the sublimation ribbon, are resistant to aging, and can increase the optical density of the printed image.

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

[0006] The first object of the present invention is to provide a thermal transfer receiving sheet comprising a printing layer, a heat insulating layer, a substrate and a back coating layer arranged in sequence from top to bottom;

[0007] The back coating layer comprises the following raw materials in parts by weight: 13-16 parts of a first resin, 2-3 parts of a filler, 0.1-0.5 parts of polyethylene glycol, and 0.01-0.05 parts of lithium chloride.

[0008] The heat insulation layer comprises the following raw materials in parts by weight: 9-11 parts of adhesive and 4-7 parts of hollow particles;

[0009] The printing layer comprises the following raw materials in parts by weight: 19-22 parts of a second resin, 0.1-1 parts of aromatic hydrocarbon-modified polysiloxane, 0.1-1 parts of polyethylene glycol, and 0.1-1 parts of a polyisocyanate curing agent.

[0010] The beneficial effects of adopting the solution of the present invention are:

[0011] (1) In the heat-insulating layer of the present invention, the adhesive is combined with the hollow particles to provide the heat-insulating layer with heat-insulating and buffering properties. The mixing ratio between the hollow particles and the adhesive is limited to prevent the substrate from being melted by heat while also having good adhesion. The printing layer is an essential structure of the thermal transfer receiving sheet of the present invention. On the printing layer, an image is formed by thermal sublimation of a thermal sublimation ribbon having a dye layer. The material used to form the printing layer is easy to receive sublimation dyes and easy to form an image on the thermal transfer receiving sheet. The back coating layer is provided on the opposite side of the printing layer of the substrate to improve the transportability of the thermal transfer receiving sheet, prevent the substrate from curling, and prevent static electricity.

[0012] (2) The thermal transfer receiving sheet prepared by the present invention can ensure that the dye does not escape under high temperature and high humidity conditions, and the overall Od value is significantly higher than that before addition, and has good aging resistance, light resistance, weather resistance, wear resistance and durability.

[0013] (3) The present invention limits the proportion of hollow particles to adhesive. If the content of hollow particles is too low relative to the adhesive, the voids in the thermal insulation layer will be reduced, and the thermal insulation and cushioning functions cannot be fully exerted. If the content of hollow particles is too high relative to the adhesive, the adhesion will be reduced, affecting the adhesion between the layers.

[0014] Furthermore, the substrate is at least one of a heat-resistant resin and paper;

[0015] The heat-resistant resin is at least one of polyester, polyarylate, polycarbonate, polyurethane, polyimide, polyetherimide, cellulose derivatives, polyethylene, ethylene-vinyl acetate copolymer, polypropylene, polystyrene, acrylic acid, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl butyral, and nylon;

[0016] The paper is at least one of capacitor paper, glassine paper, sulfate paper, synthetic paper, high-quality paper, art paper, coated paper, cast coated paper, synthetic rubber latex impregnated paper, and fiber paper.

[0017] The advantageous effects of adopting the above further solution are that the substrate of the present invention can withstand the heat applied during image formation, has mechanical properties that do not hinder handling, and can be appropriately selected according to the type of thermal transfer receiving sheet.

[0018] Furthermore, the synthetic paper is at least one of polystyrene synthetic paper and polyolefin synthetic paper.

[0019] Furthermore, the heat-resistant resin further includes an auxiliary agent.

[0020] Furthermore, the particle size of the hollow particles is 0.3-1.6 μm.

[0021] Furthermore, the thickness of the substrate is 30-300 μm, the thickness of the heat insulation layer is 1-10 μm, the thickness of the back coating layer is 1-20 μm, and the thickness of the printing layer is 1-10 μm.

[0022] The beneficial effect of adopting the above further solution is that the thickness of the thermal transfer receiving sheet can be ensured within this thickness range, while having good adhesion to the substrate and heat resistance.

[0023] Furthermore, the thickness of the substrate is 100-250 μm, the thickness of the heat insulation layer is 1-5 μm, the thickness of the back coating layer is 3-10 μm, and the thickness of the printing layer is 1-5 μm.

[0024] Furthermore, the filler is at least one of an acrylic filler, a polyamide filler, a fluorine-based filler, an organic filler, an inorganic filler, and a conductive filler.

[0025] Furthermore, the organic filler may be polyethylene wax, zinc stearate, etc.; the inorganic filler may be talc, silicon dioxide, aerated silica, etc.; the conductive filler may be metal oxide, polyaniline sulfonic acid, etc.

[0026] Furthermore, the first resin is at least one of acrylic resin, cellulose resin, polycarbonate resin, polyvinyl alcohol resin, polyvinyl butyral resin, polyamide resin, polystyrene resin, polyester resin, and halogenated polymer.

[0027] The beneficial effect of adopting the above further solution is that the back coating prepared with the above materials can prevent the substrate from curling and static electricity. Preferably, the resin has a Tg of 70°C or above and has good heat resistance. When the Tg of the resin is lower than this value, the heat resistance is obviously insufficient and it is easy to age.

[0028] Furthermore, the second resin is at least one of polyolefin resins, halogenated resins, ethylene resins, polyester resins, polystyrene resins, polyamide resins, olefin and vinyl polymer copolymer resins, cellulose resins, polycarbonate resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral resins, and silicone resins.

[0029] The beneficial effect of adopting the above further solution is that the addition of the second resin of the present invention to the printing layer can react and chelate with the heat-diffusing dye, ensuring that the dye does not overflow and escape under high temperature and high humidity conditions and has good stability.

[0030] Furthermore, the average molecular weight of the second resin is 10,000-70,000.

[0031] The above further solution has the following beneficial effects: when the molecular weight is low, the toughness of the printing layer is poor. The addition of the second resin to the printing layer can react and chelate with the heat-diffusive dye, ensuring that the dye does not escape under high temperature and high humidity conditions and maintaining good stability. When the molecular weight of the second resin is low, the toughness of the printing layer is poor and the dye is prone to escape. Resins with higher molecular weights and Tgs are more effective, but when the molecular weight is too high, the printing layer's stability is poor.

[0032] Furthermore, the molecular weight of the second resin is 50,000-60,000.

[0033] A second object of the present invention is to provide a method for preparing a thermal transfer receiving sheet, comprising the steps of:

[0034] S1: Prepare liquid: Back coating liquid: Add the first resin, filler, polyethylene glycol, and lithium chloride to a solvent and dissolve to prepare a back coating liquid, which is ready for use; Printing liquid: Add the second resin, aromatic modified polysiloxane, polyethylene glycol, and polyisocyanate curing agent to a solvent and dissolve to prepare a printing liquid, which is ready for use; Insulation liquid: Add the adhesive and hollow particles to a solvent and dissolve to prepare an insulation liquid, which is ready for use;

[0035] S2: applying corona; providing a substrate, and applying corona on at least one side of the substrate;

[0036] S3: coating; coating the back coating liquid on the corona-charged side of the substrate, and then drying to form a back coating layer for standby use; then coating the heat insulating liquid on the side of the substrate away from the back coating layer, and then drying to form a heat insulating layer; finally, coating the printing liquid on the side of the heat insulating layer away from the substrate, and then drying to form a printing layer, thereby obtaining a thermal transfer receiving sheet.

[0037] The beneficial effect of adopting the above further solution is that the thermal transfer receiving sheet prepared by the above preparation method has low production cost and simple and feasible process.

[0038] Further, in step S1, the solvent is at least one of 2-butanone and toluene;

[0039] In step S3, a gravure coater is used to apply back coating liquid, a gravure coater is used to apply heat insulation liquid, and a gravure coater is used to apply printing liquid. The coating speed is 100-150 m / min. The drying temperature is 60-100°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of the layer structure of the thermal transfer receiving sheet of the present invention.

[0041] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0042] 1-substrate, 2-back coating, 3-thermal insulation layer, 4-printing layer. DETAILED DESCRIPTION

[0043] The principles and features of the present invention are described below. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in this field or the product instructions are used. Where the manufacturers of the reagents or instruments used are not specified, they are all conventional products that can be purchased through regular channels.

[0044] Example 1: Preparation of thermal transfer receiving sheet

[0045] S1: Prepare the back coating solution: 0.5 parts of zinc stearate (SAK-ZS-PLB Singapore Samik), 0.3 parts of polyethylene glycol (PEG-600 Youso Chemical), 15 parts of polyvinyl butyral resin (S-LEC BX-1 Japan Sekisui Chemical), 0.03 parts of lithium chloride, 2 parts of silica gel (OK607 Evonik Chemical) are added to 45 parts of isopropyl alcohol and 40 parts of toluene to prepare the back coating solution for later use;

[0046] Printing liquid: Dissolve 20 parts of vinyl chloride-vinyl acetate copolymer (H15-42, Wacker Chemicals, Germany) with an average molecular weight of 35,000-50,000, a vinyl chloride content of 86%, and a glass transition temperature (Tg) of 70°C, 0.5 parts of aromatic modified polysiloxane (AFCONA-3252, Efcona Chemicals), 1 part of polyethylene glycol (PEG-600, Youso Chemicals), and 0.5 parts of polyisocyanate curing agent (TFD-90SB, Asahi Chemicals, Japan) in 37.4 parts of 2-butanone and 37.4 parts of toluene to prepare the printing liquid for later use.

[0047] Heat insulation liquid: Mix 10 parts of styrene-butadiene emulsion (101# from Yoshida Chemical), 5 parts of hollow sphere pigment with an average particle size of 1.6 μm (ROPAQUE™ TH-2000 from Dow), and 5 parts of isopropyl alcohol to make a heat insulation liquid. Set aside.

[0048] S2: Corona: Use foamed polypropylene (PP) sheet and apply EVA hot melt adhesive coating liquid on the PP sheet to make the thickness of the PP sheet 3g / m when dry. 2 , PP sheet and 140g / m 2 The substrate paper (purchased from Jinguang Paper) is laminated on both sides and PE coated on the back. The thickness when dry is 5g / m 2, drying at 110° C. for 1 minute to obtain a substrate 1 having a layer structure of foamed PP / adhesive layer / substrate paper / PE; applying a corona on one side of the substrate 1;

[0049] S3: Coating: Use a gravure coater to coat the back coating liquid on the corona-charged side of the substrate 1 at a coating speed of 130m / min, with a coating thickness of 5μm, and then dry it at 80℃ to form a back coating layer 2 for standby use; then use a gravure coater to coat the heat insulation liquid on the side of the substrate 1 away from the back coating layer 2 at a coating speed of 130m / min, with a coating thickness of 2μm, and then dry it at 80℃ to form a heat insulation layer 3; finally, use a gravure coater to coat the printing liquid on the side of the heat insulation layer 3 away from the substrate 1 at a coating speed of 130m / min, with a coating thickness of 6μm, and then dry it at 80℃ to form a printing layer 4, thereby obtaining a thermal transfer receiving sheet.

[0050] Example 2: Preparation of thermal transfer receiving sheet II

[0051] S1: Prepare the back coating solution: 0.5 parts of zinc stearate (SAK-ZS-PLB Singapore Samik), 0.3 parts of polyethylene glycol (PEG-600 Youso Chemical), 15 parts of polyvinyl butyral resin (S-LEC BX-1 Japan Sekisui Chemical), 0.03 parts of lithium chloride, 2 parts of silica gel (OK607 Evonik Chemical) are added to 45 parts of isopropyl alcohol and 40 parts of toluene to prepare the back coating solution for later use;

[0052] Printing fluid: Dissolve 18 parts of vinyl chloride-vinyl acetate copolymer (H15-42, Wacker Chemical, Germany) with an average molecular weight of 35,000-50,000, a vinyl chloride content of 86%, and a glass transition temperature (Tg) of 70°C; 2 parts of polyvinyl butyral resin (BA-20S, Sekisui Chemical, Japan); 0.5 parts of aromatic modified polysiloxane (AFCONA-3252, Efcona Chemical); 1 part of polyethylene glycol (PEG-600, Youso Chemical); and 0.5 parts of polyisocyanate curing agent (TFD-90SB, Asahi Chemical, Japan) in 37.4 parts of 2-butanone and 37.4 parts of toluene to prepare the printing fluid for later use.

[0053] Heat insulation liquid: Mix 10 parts of styrene-butadiene emulsion (101# from Yoshida Chemical), 5 parts of hollow sphere pigment with an average particle size of 1.6 μm (ROPAQUE™ TH-2000 from Dow), and 5 parts of isopropyl alcohol to make a heat insulation liquid. Set aside.

[0054] S2: Corona: Use foamed polypropylene (PP) sheet and apply EVA hot melt adhesive coating liquid on the PP sheet to make the thickness of the PP sheet 3g / m when dry. 2 , PP sheet and 140g / m 2 The substrate paper (purchased from Jinguang Paper) is laminated on both sides and PE coated on the back. The thickness when dry is 5g / m2 The substrate 1 was dried at 110° C. for 1 minute to obtain a layer structure of foamed PP / adhesive layer / base paper / PE; a corona was applied on one side of the substrate 1;

[0055] S3: Coating: Use a gravure coater to coat the back coating liquid on the corona-charged side of the substrate 1 at a coating speed of 130m / min, with a coating thickness of 3μm, and then dry it at 80℃ to form a back coating layer 2 for standby use; then use a gravure coater to coat the heat insulation liquid on the side of the substrate 1 away from the back coating layer 2 at a coating speed of 130m / min, with a coating thickness of 1μm, and then dry it at 80℃ to form a heat insulation layer 3; finally, use a gravure coater to coat the printing liquid on the side of the heat insulation layer 3 away from the substrate 1 at a coating speed of 130m / min, with a coating thickness of 4μm, and then dry it at 80℃ to form a printing layer 4, thereby obtaining a thermal transfer receiving sheet.

[0056] Example 3: Preparation of thermal transfer receiving sheet

[0057] S1: Prepare the back coating solution: 0.5 parts of zinc stearate (SAK-ZS-PLB Singapore Samik), 0.3 parts of polyethylene glycol (PEG-600 Youso Chemical), 15 parts of polyvinyl butyral resin (S-LEC BX-1 Japan Sekisui Chemical), 0.03 parts of lithium chloride, 2 parts of silica gel (OK607 Evonik Chemical) are added to 45 parts of isopropyl alcohol and 40 parts of toluene to prepare the back coating solution for later use;

[0058] Printing liquid: Dissolve 20 parts of vinyl chloride-vinyl acetate copolymer (SOLBIN-C, Nissin Chemical), 0.5 parts of aromatic hydrocarbon-modified polysiloxane (AFCONA-3252, Efcona Chemical), 1 part of polyethylene glycol (PEG-600, Youso Chemical), and 0.5 parts of polyisocyanate curing agent (TFD-90SB, Asahi Chemical, Japan) in 37.4 parts of 2-butanone and 37.4 parts of toluene to prepare the printing liquid. Set aside.

[0059] Heat insulation liquid: Mix 10 parts of styrene-butadiene emulsion (101# from Yoshida Chemical), 5 parts of hollow sphere pigment with an average particle size of 1.6 μm (ROPAQUE™ TH-2000 from Dow), and 5 parts of isopropyl alcohol to make a heat insulation liquid. Set aside.

[0060] S2: Corona: Use foamed polypropylene (PP) sheet and apply EVA hot melt adhesive coating liquid on the PP sheet to make the thickness of the PP sheet 3g / m when dry. 2 , PP sheet and 140g / m 2 The substrate paper is laminated on both sides and the back side is PE coated. The thickness when dry is 5g / m 2 The substrate 1 was dried at 110° C. for 1 minute to obtain a layer structure of foamed PP / adhesive layer / base paper / PE; a corona was applied on one side of the substrate 1;

[0061] S3: Coating: Use a gravure coater to coat the back coating liquid on the corona-charged side of the substrate 1 at a coating speed of 130m / min, with a coating thickness of 6μm, and then dry it at 80℃ to form a back coating layer 2 for standby use; then use a gravure coater to coat the heat insulation liquid on the side of the substrate 1 away from the back coating layer 2 at a coating speed of 130m / min, with a coating thickness of 1-3μm, and then dry it at 80℃ to form a heat insulation layer 3; finally, use a gravure coater to coat the printing liquid on the side of the heat insulation layer 3 away from the substrate 1 at a coating speed of 130m / min, with a coating thickness of 4-7μm, and then dry it at 80℃ to form a printing layer 4, thereby obtaining a thermal transfer receiving sheet.

[0062] Example 4: Preparation of thermal transfer receiving sheet

[0063] S1: Prepare the back coating solution: 0.5 parts of zinc stearate (SAK-ZS-PLB Singapore Samik), 0.3 parts of polyethylene glycol (PEG-600 Youso Chemical), 15 parts of polyvinyl butyral resin (S-LEC BX-1 Japan Sekisui Chemical), 0.03 parts of lithium chloride, 2 parts of silica gel (OK607 Evonik Chemical) are added to 45 parts of isopropyl alcohol and 40 parts of toluene to prepare the back coating solution for later use;

[0064] Printing liquid: Dissolve 20 parts of vinyl chloride-vinyl acetate copolymer (SOLBIN-C, Nissin Chemical), 0.5 parts of silicone resin (BYK-323, Germany), 1 part of polyethylene glycol (PEG-600, Youso Chemical), and 0.5 parts of polyisocyanate curing agent (TFD-90SB, Asahi Chemical, Japan) in 37.4 parts of 2-butanone and 37.4 parts of toluene to prepare the printing liquid. Set aside.

[0065] Heat insulation liquid: Mix 10 parts of styrene-butadiene emulsion (101# from Yoshida Chemical), 5 parts of hollow sphere pigment with an average particle size of 1.6 μm (ROPAQUE™ TH-2000 from Dow), and 5 parts of isopropyl alcohol to make a heat insulation liquid. Set aside.

[0066] S2: Corona: Use foamed polypropylene (PP) sheet and apply EVA hot melt adhesive coating liquid on the PP sheet to make the thickness of the PP sheet 3g / m when dry. 2 , PP sheet and 140g / m 2 The substrate paper (purchased from Jinguang Paper) is laminated on both sides and PE coated on the back. The thickness when dry is 5g / m 2 The substrate 1 was dried at 110° C. for 1 minute to obtain a layer structure of foamed PP / adhesive layer / base paper / PE; a corona was applied on one side of the substrate 1;

[0067] S3: Coating: Use a gravure coater to coat the back coating liquid on the corona-charged side of the substrate 1 at a coating speed of 130m / min, with a coating thickness of 3-6μm, and then dry it at 80℃ to form a back coating layer 2 for standby use; then use a gravure coater to coat the heat insulation liquid on the side of the substrate away from the back coating layer 2 at a coating speed of 130m / min, with a coating thickness of 1-3μm, and then dry it at 80℃ to form a heat insulation layer 3; finally, use a gravure coater to coat the printing liquid on the side of the heat insulation layer 3 away from the substrate 1 at a coating speed of 130m / min, with a coating thickness of 4-7μm, and then dry it at 80℃ to form a printing layer 4, thereby obtaining a thermal transfer receiving sheet.

[0068] Example 5: Preparation of thermal transfer receiving sheet

[0069] S1: Prepare the back coating solution: 0.5 parts of zinc stearate (SAK-ZS-PLB Singapore Samik), 0.3 parts of polyethylene glycol (PEG-600 Youso Chemical), 15 parts of polyvinyl butyral resin (S-LEC BX-1 Japan Sekisui Chemical), 0.03 parts of lithium chloride, 2 parts of silica gel (OK607 Evonik Chemical) are added to 45 parts of isopropyl alcohol and 40 parts of toluene to prepare the back coating solution for later use;

[0070] Printing liquid: Dissolve 20 parts of vinyl chloride-vinyl acetate copolymer (H40-60, Wacker Chemical, Germany) with an average molecular weight of 100,000-140,000, a vinyl chloride content of 61%, and a glass transition temperature (Tg) of 62°C, 0.5 parts of aromatic modified polysiloxane (AFCONA-3252, Efcona Chemical), 1 part of polyethylene glycol (PEG-600, Youso Chemical), and 0.5 parts of polyisocyanate curing agent (TFD-90SB, Asahi Chemical, Japan) in 37.4 parts of 2-butanone and 37.4 parts of toluene to prepare the printing liquid for later use.

[0071] Heat-insulating liquid: Mix 10 parts of styrene-butadiene emulsion (101# Yoshida Chemical), 5 parts of hollow sphere pigment with an average particle size of 1.6 μm (ROPAQUE™ TH-2000 Dow), and 5 parts of isopropyl alcohol to make a heat-insulating liquid for later use.

[0072] S2: Corona: Use foamed polypropylene (PP) sheet and apply EVA hot melt adhesive coating liquid on the PP sheet to make the thickness of the PP sheet 3g / m when dry. 2 , PP sheet and 140g / m 2 The substrate paper (purchased from Jinguang Paper) is laminated on both sides and PE coated on the back. The thickness when dry is 5g / m 2 The substrate 1 was dried at 110° C. for 1 minute to obtain a layer structure of foamed PP / adhesive layer / base paper / PE; a corona was applied on one side of the substrate 1;

[0073] S3: Coating: Use a gravure coater to coat the back coating liquid on the corona-charged side of the substrate 1 at a coating speed of 130m / min, with a coating thickness of 3-6μm, and then dry it at 80℃ to form a back coating layer 2 for standby use; then use a gravure coater to coat the heat insulation liquid on the side of the substrate away from the back coating layer 2 at a coating speed of 130m / min, with a coating thickness of 1-3μm, and then dry it at 80℃ to form a heat insulation layer 3; finally, use a gravure coater to coat the printing liquid on the side of the heat insulation layer 3 away from the substrate 1 at a coating speed of 130m / min, with a coating thickness of 4-7μm, and then dry it at 80℃ to form a printing layer 4, thereby obtaining a thermal transfer receiving sheet.

[0074] Comparative Example 1: Preparation of thermal transfer receiving sheet

[0075] The difference between this comparative example and Example 1 is only the change in the raw materials for preparing the thermal insulation liquid. The remaining raw materials and steps are the same as those in Example 1. Step S1 is as follows:

[0076] S1: Preparation solution:

[0077] Back coating liquid: 0.5 parts of zinc stearate (SAK-ZS-PLB Singapore Samick), 0.3 parts of polyethylene glycol (PEG-600 Youso Chemical), 15 parts of polyvinyl butyral resin (S-LEC BX-1 Japan Sekisui Chemical), 0.03 parts of lithium chloride, 2 parts of silica gel (OK607 Evonik Chemical) are added to 45 parts of isopropyl alcohol and 40 parts of toluene to prepare the back coating liquid and set aside;

[0078] Printing liquid: Dissolve 20 parts of vinyl chloride-vinyl acetate copolymer (H15-42, Wacker Chemicals, Germany), 0.5 parts of aromatic hydrocarbon-modified polysiloxane (AFCONA-3252, Efcona Chemicals), 1 part of polyethylene glycol (PEG-600, Youso Chemicals), and 0.5 parts of polyisocyanate curing agent (TFD-90SB, Asahi Chemicals, Japan) in 37.4 parts of 2-butanone and 37.4 parts of toluene to prepare the printing liquid. Set aside.

[0079] Heat-insulating liquid: Mix 10 parts of styrene-butadiene emulsion (101# Yoshida Chemical), 5 parts of hollow sphere pigment with an average particle size of 0.4 μm (ROPAQUE™ HP-380 Dow), and 5 parts of isopropyl alcohol to make a heat-insulating liquid and set aside.

[0080] Comparative Example 2: Preparation of thermal transfer receiving sheet

[0081] The only difference between this comparative example and Example 1 is that no thermal insulation liquid and thermal insulation layer are prepared. The remaining preparation materials and steps are the same as those in Example 1. Step S1 is as follows:

[0082] S1: Preparation solution:

[0083] Back coating solution: 0.5 parts of zinc stearate (SAK-ZS-PLB Singapore Samick), 0.3 parts of polyethylene glycol (PEG-600 Youso Chemical), 15 parts of polyvinyl butyral resin (S-LEC BX-1 Japan Sekisui Chemical), 0.03 parts of lithium chloride, 2 parts of gas silicon (S-LEC BX-1 Japan Sekisui Chemical) are added to 45 parts of isopropyl alcohol and 40 parts of toluene to prepare the back coating solution and set aside;

[0084] Printing liquid: Dissolve 20 parts of vinyl chloride-vinyl acetate copolymer (H15-42, Wacker Chemicals, Germany), 0.5 parts of aromatic hydrocarbon-modified polysiloxane (AFCONA-3252, Efcona Chemicals), 1 part of polyethylene glycol (PEG-600, Youso Chemicals), and 0.5 parts of polyisocyanate curing agent (TFD-90SB, Asahi Chemicals, Japan) in 37.4 parts of 2-butanone and 37.4 parts of toluene to prepare the printing liquid. Set aside.

[0085] S2: Corona: Use foamed polypropylene (PP) sheet and apply EVA hot melt adhesive coating liquid on the PP sheet to make the thickness of the PP sheet 3g / m when dry. 2 , PP sheet and 140g / m 2 The substrate paper (purchased from Jinguang Paper) is laminated on both sides and PE coated on the back. The thickness when dry is 5g / m 2 The substrate 1 was dried at 110° C. for 1 minute to obtain a layer structure of foamed PP / adhesive layer / base paper / PE; a corona was applied on one side of the substrate 1;

[0086] S3: coating; a gravure coater is used to coat the back coating liquid on the corona-charged side of the substrate 1 at a coating speed of 130 m / min, with a coating thickness of 5 μm, and then dried at 80°C to form a back coating layer 2 for standby use; finally, a gravure coater is used to coat the printing liquid on the side of the back coating layer 2 away from the substrate 1 at a coating speed of 130 m / min, with a coating thickness of 6 μm, and then dried at 80°C to form a printing layer 4, thereby obtaining a thermal transfer receiving sheet.

[0087] Comparative Example 3: Preparation of thermal transfer receiving sheet

[0088] The only difference between this comparative example and Example 1 is that no back coating liquid and back coating layer are prepared. The remaining preparation materials and steps are the same as those in Example 1. Step S1 is as follows:

[0089] S1: Preparation solution:

[0090] Printing liquid: Dissolve 20 parts of vinyl chloride-vinyl acetate copolymer (H15-42, Wacker Chemicals, Germany), 0.5 parts of aromatic hydrocarbon-modified polysiloxane (AFCONA-3252, Efcona Chemicals), 1 part of polyethylene glycol (PEG-600, Youso Chemicals), and 0.5 parts of polyisocyanate curing agent (TFD-90SB, Asahi Chemicals, Japan) in 37.4 parts of 2-butanone and 37.4 parts of toluene to prepare the printing liquid. Set aside.

[0091] Heat insulation liquid: Mix 10 parts of styrene-butadiene emulsion (101# from Yoshida Chemical), 5 parts of hollow sphere pigment with an average particle size of 1.6 μm (ROPAQUE™ TH-2000 from Dow), and 5 parts of isopropyl alcohol to make a heat insulation liquid. Set aside.

[0092] S2: Corona: Use foamed polypropylene (PP) sheet and apply EVA hot melt adhesive coating liquid on the PP sheet to make the thickness of the PP sheet 3g / m when dry. 2 , PP sheet and 140g / m 2 The substrate paper (purchased from Jinguang Paper) is laminated on both sides and PE coated on the back. The thickness when dry is 5g / m 2 The substrate 1 was dried at 110° C. for 1 minute to obtain a layer structure of foamed PP / adhesive layer / base paper / PE; a corona was applied on one side of the substrate 1;

[0093] S3: coating; using a gravure coater to coat the insulation liquid on the side of the substrate 1 away from the electrostatic discharge at a coating speed of 130m / min, the coating thickness is 2μm, and then drying at 80℃ to form an insulation layer 3; using a gravure coater to coat the printing liquid on the side of the insulation layer 3 away from the substrate 1 at a coating speed of 130m / min, the coating thickness is 6μm, and then drying at 80℃ to form a printing layer 4, thus obtaining a thermal transfer receiving sheet.

[0094] Comparative Example 4: Preparation of thermal transfer receiving sheet

[0095] The only difference between this comparative example and Example 2 is that the raw materials used in the printing liquid are different. The BA-20S resin with an average molecular weight of 15,000-25,000 and a glass transition temperature (Tg) of 84°C is replaced with a BA-55HH resin with a Tg (glass transition temperature) of 92°C and a molecular weight of 50,000-60,000. The remaining raw materials and steps are the same as those in Example 1. The specific steps are as follows:

[0096] S1: Prepare the back coating solution: 0.5 parts of zinc stearate (SAK-ZS-PLB Singapore Samik), 0.3 parts of polyethylene glycol (PEG-600 Youso Chemical), 15 parts of polyvinyl butyral resin (S-LEC BX-1 Japan Sekisui Chemical), 0.03 parts of lithium chloride, 2 parts of silica gel (OK607 Evonik Chemical) are added to 45 parts of isopropyl alcohol and 40 parts of toluene to prepare the back coating solution for later use;

[0097] Printing fluid: Dissolve 18 parts of vinyl chloride-vinyl acetate copolymer (H15-42, Wacker Chemicals, Germany), 2 parts of polyvinyl butyral resin (BA-55HH, Sekisui Chemical, Japan), 0.5 parts of aromatic modified polysiloxane (AFCONA-3252, Efcona Chemicals), 1 part of polyethylene glycol (PEG-600, Youso Chemicals), and 0.5 parts of polyisocyanate curing agent (TFD-90SB, Asahi Chemicals, Japan) in 37.4 parts of 2-butanone and 37.4 parts of toluene to prepare the printing fluid for later use.

[0098] S2: Corona: Use foamed polypropylene (PP) sheet and apply EVA hot melt adhesive coating liquid on the PP sheet to make the thickness of the PP sheet 3g / m when dry. 2 , PP sheet and 140g / m 2 The substrate paper (purchased from Jinguang Paper) is laminated on both sides and PE coated on the back. The thickness when dry is 5g / m 2 The substrate 1 was dried at 110° C. for 1 minute to obtain a layer structure of foamed PP / adhesive layer / base paper / PE; a corona was applied on one side of the substrate 1;

[0099] S3: coating; a gravure coater is used to coat the back coating liquid on the corona-charged side of the substrate 1 at a coating speed of 130 m / min, with a coating thickness of 5 μm, and then dried at 80°C to form a back coating layer 2 for standby use; a gravure coater is then used to coat the heat-insulating liquid on the side of the substrate 1 away from the back coating layer 2 at a coating speed of 130 m / min, with a coating thickness of 2 μm, and then dried at 80°C to form a heat-insulating layer 3; finally, a gravure coater is used to coat the printing liquid on the other side of the substrate 1 at a coating speed of 130 m / min, with a coating thickness of 6 μm, and then dried at 80°C to form a printing layer 4, thereby obtaining a thermal transfer receiving sheet.

[0100] Test example: performance test

[0101] The samples prepared in Examples 1-4 and Comparative Examples 1-5 were printed using a DNP DS620 thermal sublimation printer. The original DNP DS620 ribbon was used for printing and artificial accelerated weathering testing. The artificial accelerated weathering testing was conducted in accordance with the GB / T 1865-2009 standard. The maximum optical density, color difference ΔE, and Od retention were tested using an X-Rite densitometer and a colorimeter.

[0102] Table 1

[0103]

[0104] From Table 1, we can get:

[0105] Under high temperature and high humidity conditions (90%, 60℃), the back coating layer has a significant effect on improving the Od retention rate of the thermal transfer receiving sheet; the sufficient void structure in the thermal insulation layer can play a role in improving the Od value. The smaller the particle size of the hollow particles in the thermal insulation layer, the denser the overall voids and the higher the Od value; the addition of polyvinyl butyral resin in the printing layer can react and chelate with the heat-diffusing dye, ensuring that the dye does not overflow and escape under high temperature and high humidity conditions. The overall Od value is significantly higher than before addition, and the effect of resins with higher molecular weight and Tg is more obvious.

[0106] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A thermal transfer receiving sheet, characterized in that: The thermal transfer receiving sheet comprises a printing layer, a heat insulating layer, a base material and a back coating layer arranged in sequence from top to bottom; The back coating layer comprises the following parts by weight of raw materials: 13-16 parts of a first resin, 2-3 parts of a filler, 0.1-0.5 parts of polyethylene glycol, 0.01-0.05 parts of lithium chloride; The heat insulation layer comprises the following raw materials in parts by weight: 9-11 parts of adhesive and 4-7 parts of hollow particles; The printing layer comprises the following raw materials in parts by weight: 19-22 parts of a second resin, 0.1-1 parts of an aromatic hydrocarbon-modified polysiloxane, 0.1-1 parts of polyethylene glycol, and 0.1-1 parts of a polyisocyanate curing agent; The particle size of the hollow particles is 0.3-1.6 μm; The filler is at least one of acrylic filler, polyamide filler, fluorine filler, organic filler, inorganic filler, and conductive filler; The first resin is at least one of acrylic resin, cellulose resin, polycarbonate resin, polyvinyl alcohol resin, polyvinyl butyral resin, polyamide resin, polystyrene resin, polyester resin, and halogenated polymer; The second resin is at least one of polyolefin resins, halogenated resins, vinyl resins, polyester resins, polystyrene resins, polyamide resins, olefin and vinyl polymer copolymer resins, cellulose resins, polycarbonate resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral resins, and silicone resins; The average molecular weight of the second resin is 10,000-70,000.

2. A thermal transfer receiving sheet according to claim 1, characterized in that: The substrate is at least one of a heat-resistant resin and paper; The heat-resistant resin is at least one of polyester, polyarylate, polycarbonate, polyurethane, polyimide, polyetherimide, cellulose derivatives, polyethylene, ethylene-vinyl acetate copolymer, polypropylene, polystyrene, acrylic acid, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl butyral, and nylon; The paper is at least one of capacitor paper, glassine paper, sulfate paper, synthetic paper, high-quality paper, art paper, coated paper, cast coated paper, synthetic rubber latex impregnated paper, and fiber paper.

3. A thermal transfer receiving sheet according to claim 1, characterized in that: The thickness of the substrate is 30-300 μm, the thickness of the heat-insulating layer is 1-10 μm, the thickness of the back coating layer is 1-20 μm, and the thickness of the printing layer is 1-10 μm.

4. A method for preparing a thermal transfer receiving sheet according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1: Prepare liquid: Back coating liquid: Add the first resin, filler, polyethylene glycol, and lithium chloride to a solvent and dissolve to prepare a back coating liquid, which is ready for use; Printing liquid: Add the second resin, aromatic modified polysiloxane, polyethylene glycol, and polyisocyanate curing agent to a solvent and dissolve to prepare a printing liquid, which is ready for use; Insulation liquid: Add the adhesive and hollow particles to a solvent and dissolve to prepare an insulation liquid, which is ready for use; S2: applying corona; providing a substrate, and applying corona on at least one side of the substrate; S3: coating; coating the back coating liquid on the corona-charged side of the substrate, and then drying to form a back coating layer for standby use; then coating the heat insulating liquid on the side of the substrate away from the back coating layer, and then drying to form a heat insulating layer; finally, coating the printing liquid on the side of the heat insulating layer away from the substrate, and then drying to form a printing layer, thereby obtaining a thermal transfer receiving sheet.

5. The method for preparing a thermal transfer receiving sheet according to claim 4, wherein: In step S1, the solvent is at least one of 2-butanone and toluene; In step S3, a gravure coater is used to apply back coating liquid, a gravure coater is used to apply heat insulation liquid, and a gravure coater is used to apply printing liquid. The coating speed is 100-150 m / min. The drying temperature is 60-100°C.

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