A highly concentrated and uniform coated paper coating suitable for thermal sublimation soft label printing

Abstract

The present invention belongs to the technical field of thermal sublimation printing, and specifically relates to a high-concentration and high-uniformity coated paper coating suitable for thermal sublimation soft label printing, which comprises a coated paper substrate, a primer layer and a dye receiving layer arranged in sequence, or comprises a coated paper substrate and a dye receiving layer arranged in sequence. The present invention improves the flatness of the dye receiving layer by improving the adhesion of the primer layer, thereby improving the printing uniformity, improves the dye receiving capacity of the dye receiving layer by improving the thermal insulation of the primer layer, thereby improving the printing color concentration, and improves the heat resistance of the dye receiving layer, thereby avoiding adhesion and color halo between the dye receiving layer and the color ribbon during printing. Through the above means, the coated paper can be guaranteed to have high color concentration and high uniformity when used for thermal sublimation soft label printing, and the abnormalities of color halo and discoloration will not occur.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal sublimation printing, and in particular relates to a high-concentration and high-uniformity coated paper coating suitable for thermal sublimation soft label printing. Background Art

[0002] Thermal sublimation printing technology is often used to replace traditional photo printing because it can achieve continuous color gradation printing. At present, there is no direct application of thermal sublimation ribbon to soft label printing on the market. The main reasons are the following problems: 1. Thermal sublimation ribbon image printing requires a special dye receiving coating, otherwise the color concentration is very low; 2. The coated paper commonly used in soft label printing will inevitably lead to uneven adhesion between the ribbon and the dye receiving layer due to the uneven density of paper fibers, which will inevitably lead to uneven light and dark of the printed image. The present invention provides a coating design on the surface of coated paper, which can ensure high color concentration and high uniformity when the coated paper is used for thermal sublimation soft label printing. Summary of the invention

[0003] In order to solve the deficiencies of the prior art, the present invention provides a high-concentration and high-uniformity coated paper coating suitable for thermal sublimation soft label printing. The coating improves the flatness of the dye receiving layer by improving the adhesion of the base coating, thereby improving the printing uniformity, improves the dye receiving capacity of the dye receiving layer by improving the thermal insulation of the base coating, thereby improving the printing color concentration, and improves the heat resistance of the dye receiving layer to avoid adhesion and color halo between the dye receiving layer and the color ribbon during printing. Through the above means, the coated paper can be guaranteed to have high color concentration and high uniformity when used for thermal sublimation soft label printing, and the abnormalities of color halo and discoloration will not occur.

[0004] The technical solution provided by the present invention is as follows:

[0005] A high-concentration and high-uniformity coated paper coating suitable for thermal sublimation soft label printing comprises a coated paper substrate, a primer layer and a dye receiving layer arranged in sequence, or comprises a coated paper substrate and a dye receiving layer arranged in sequence.

[0006] As for the base material of coated paper coating:

[0007] The coated paper and its surface coating of the present invention include a coated paper substrate, which can be a type of coated paper with adhesive backing and glassine base paper commonly used for packaging printing on the market, or a double-sided or single-sided coated paper.

[0008] Furthermore, the thickness of the coated paper substrate is 50-250 μm, and the gram weight is 40-200 g / m 2 ,

[0009] Generally speaking, the coated paper substrate can be calendered before coating, or it can be left untreated. After coating, it needs to be moisturized to prevent the paper from shrinking and wrinkling.

[0010] As for the material of the base coating of coated paper:

[0011] The main function of the base coat is to make the rough surface smooth, improve the flatness of the dye receiving layer, and thus improve the uniformity of the printed image. Generally, the optional resin is polyester resin, polyurethane resin, polycarbonate resin and acrylic resin, etc., and the preferred resin is thermoplastic polyurethane resin (TPU). TPU can make the dye receiving layer and the thermal sublimation ribbon fit closely on the print head during printing due to its good elasticity, thereby improving the uniformity of printing. According to the actual test of the inventor, simply using TPU as the base coat, for the coated paper with higher gram weight and higher density, the uniformity of the scheme is better. However, for the coated paper with lower gram weight but thicker thickness (lower density), the printing uniformity of the low color scale area of ​​the scheme is very poor. The adhesion of the base coat can be improved by mixing a certain amount of silane coupling agent or curing agent in TPU, generally speaking, the addition amount is 1-5phr of TPU, preferably 1-2.5phr is added. If too little is added, there is no obvious improvement, and if too much is added, there is a risk of the dye receiving layer bonding with the ribbon.

[0012] The solvent may be a mixed solvent of butanone and toluene.

[0013] Furthermore, in order to improve the brightness of the dye receiving layer, a certain amount of rutile titanium dioxide and fluorescent brightener can be added to the base coat. The amount of titanium dioxide added is 80-120% of the resin, and the amount of fluorescent brightener added is 0.05-0.1% of the total amount of titanium dioxide and resin.

[0014] Further, in order to improve the dye receiving ability of the dye receiving layer, a certain amount of heat insulating material can be added to the base coat, such as silicone resin particles, gas silicon, foamed polyurethane or hollow microspheres, metal inorganic oxides such as aluminum oxide, zinc oxide, titanium oxide, etc., and the addition amount is 1-5phr of TPU, preferably 1-2.5phr. The melting point of the heat insulating material is higher than 300°C, and the particle size is 1-5μm. The preferred heat insulating material is silicone resin particles or foamed polyurethane, and the particle size is less than 3μm. Too large a particle size will affect the surface smoothness of the coating, and too much addition will also affect the surface smoothness of the coating, and too little will not work.

[0015] The recommended coating thickness of the primer layer is 1-5 μm, and the preferred thickness is 2-4 μm.

[0016] As for the material of the dye receiving layer:

[0017] The main function of the dye receiving layer is to receive the thermal sublimation dye. The main resin is preferably a halogenated resin such as polyvinyl chloride or polyvinylidene chloride and a vinyl chloride-vinyl acetate copolymer, preferably a vinyl chloride-vinyl acetate copolymer, and the ratio of vinyl chloride to vinyl acetate is in the range of 80:20-90:10.

[0018] The solvent may be a mixed solvent of butanone and toluene.

[0019] In order to prevent the problem of bonding between the dye receiving layer and the color ribbon due to heating and causing the resin to melt during printing, a certain amount of anti-tack agent needs to be added in the dye receiving layer for anti-tack. Because in the thermal sublimation printing process, the dye receiving layer is in close contact with the color ribbon, the liquid lubricant in the dye receiving layer will gradually migrate to the color ribbon surface, and the substrate at the same position will contact the color ribbon 3 times, which will increase the risk of bonding between the dye receiving layer and the color ribbon step by step. In order to solve this problem, the present invention adopts the following scheme: add a certain amount of reactive silicone oil and curing agent, and the addition amount is 0.5-1.5phr of resin to fix silicone oil and main resin by reaction, increase the adhesion and adhesion of the dye receiving layer, and reduce the thermal migration of silicone oil.

[0020] The above problem can also be solved by the following method: adding a certain amount of two non-reactive silicone oils, one of which is a benzene ring modified polyether silicone oil, which can provide good slipperiness at high temperature (about 200°C), and the other is an epoxy modified silicone oil, which can provide good slipperiness at low and medium temperatures. These two correspond to the low, medium and high color levels of thermal sublimation printing, that is, when printing different concentrations, the coating provided by the present invention can maintain excellent slipperiness, thereby avoiding the problem of color halation or even color fading caused by the adhesion of the ribbon and the dye receiving layer during printing.

[0021] The dye receiving layer is recommended to be coated in a thickness of 5-15 μm, preferably 5-10 μm. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The present invention is a schematic structural diagram of a high-concentration and high-uniformity coated paper coating suitable for thermal sublimation soft label printing.

[0023] Attached Figure 1 The structures represented by the labels are listed below:

[0024] 1. Coated paper substrate, 2. Primer layer, 3. Dye receiving layer. DETAILED DESCRIPTION

[0025] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0026] Unless otherwise specified, the following formulas are expressed in parts by mass:

[0027] Example 1:

[0028] The substrate used is 80μm thick and weighs 75g / m 2 The coated paper is manufactured by Zhongshan Xinguan Adhesive Products.

[0029] <Base coating>:

[0030] Polyurethane (905H Wanhua Chemical) 20 parts

[0031] 0.5 parts of silicone resin particles (KMP 590 Shin-Etsu silicone)

[0032] Silane coupling agent (KBM 603 Shin-Etsu silicone) 0.5 parts

[0033] 2-Butanone 39.5 parts

[0034] Toluene 39.5 parts

[0035] Coating was done by gravure coater, with a coating thickness of 4 μm.

[0036] <Dye receiving layer>:

[0037] Vinyl chloride-vinyl acetate copolymer (MLC-14-55 Pangao Chemical) 20 parts

[0038] Silicone resin (reactive KF-6123 Shin-Etsu silicone) 0.5 parts

[0039] Isocyanate ( MDI-50F Wanhua Chemical) 0.5 parts

[0040] 2-Butanone 39.5 parts

[0041] Toluene 39.5 parts

[0042] Coating was done by gravure coater, with a coating thickness of 5 μm.

[0043] Example 2:

[0044] The substrate used is 80μm thick and weighs 75g / m 2 The coated paper is manufactured by Zhongshan Xinguan Adhesive Products.

[0045] <Base coating>:

[0046] Polyurethane (905H Wanhua Chemical) 10 parts

[0047] 5 parts of polyurethane foam (2040M Changxing Chemical Industry)

[0048] Titanium dioxide (BLR-699 Hebei Bangti) 8 parts

[0049] Fluorescent brightener (LR-B Henan Longrui Chemical) 0.2 parts

[0050] 2-Butanone 38.4 parts

[0051] Toluene 38.4 parts

[0052] Coating was done by gravure coater, with a coating thickness of 4 μm.

[0053] The scheme of <Dye Receiving Layer> is the same as that of Example 1.

[0054] Example 3:

[0055] The substrate used is 80μm thick and weighs 75g / m 2 The coated paper is manufactured by Zhongshan Xinguan Adhesive Products.

[0056] The <Base Coating> scheme is consistent with Example 1.

[0057] <Dye receiving layer>:

[0058] Vinyl chloride-vinyl acetate copolymer (MLC-14-55 Pangao Chemical) 20 parts

[0059] 0.5 parts of silicone resin (normal temperature anti-stick KF-105 Shin-Etsu silicone)

[0060] Silicone resin (BYK-322, Germany) 0.5 parts

[0061] 2-Butanone 39.5 parts

[0062] Toluene 39.5 parts

[0063] Coating was done by gravure coater, with a coating thickness of 5 μm.

[0064] Example 4:

[0065] The substrate used is 80μm thick and weighs 75g / m 2 The coated paper is manufactured by Zhongshan Xinguan Adhesive Products.

[0066] The <Base Coating> scheme is consistent with Example 2.

[0067] <Dye receiving layer>:

[0068] Vinyl chloride-vinyl acetate copolymer (MLC-14-55 Pangao Chemical) 20 parts

[0069] Silicone resin (KF-105 Shin-Etsu silicone) 0.5 parts

[0070] Silicone resin (BYK-322, Germany) 0.5 parts

[0071] 2-Butanone 39.5 parts

[0072] Toluene 39.5 parts

[0073] Coating was done by gravure coater, with a coating thickness of 5 μm.

[0074] Comparative Example 1:

[0075] The substrate used is 80μm thick and weighs 75g / m 2 The coated paper is manufactured by Zhongshan Xinguan Adhesive Products.

[0076] No primer or dye receiving layer.

[0077] Comparative Example 2:

[0078] The substrate used is 80μm thick and weighs 75g / m 2 The coated paper is manufactured by Zhongshan Xinguan Adhesive Products.

[0079] There is no primer layer and the dye receiving layer is consistent with Example 1.

[0080] Comparative Example 3:

[0081] The substrate used is 80μm thick and weighs 75g / m 2 The coated paper is manufactured by Zhongshan Xinguan Adhesive Products.

[0082] There is no primer layer and the dye receiving layer is the same as Example 3.

[0083] Comparative Example 4:

[0084] The substrate used is 80μm thick and weighs 75g / m 2 The coated paper is manufactured by Zhongshan Xinguan Adhesive Products.

[0085] <Base coating>:

[0086] Polyurethane (905H Wanhua Chemical) 20 parts

[0087] 2-Butanone 39.5 parts

[0088] Toluene 39.5 parts

[0089] Coating by gravure coater, coating thickness 4μm

[0090] The same as Example 1 was used for the dye receiving layer.

[0091] Comparative Example 5:

[0092] The substrate used is 80μm thick and weighs 75g / m 2 The coated paper is manufactured by Zhongshan Xinguan Adhesive Products.

[0093] <Base coating>:

[0094] Polyurethane (905H Wanhua Chemical) 20 parts

[0095] 2-Butanone 39.5 parts

[0096] Toluene 39.5 parts

[0097] Coating by gravure coater, coating thickness 4μm

[0098] The same as Example 3.

[0099] Performance test plan:

[0100] The printing test was conducted using a DNP DS620 thermal sublimation printer. The ribbon used was the original DNP DS620 ribbon. The color density test pattern was a 255-grayscale image, the color uniformity test pattern was a 150-grayscale image, and the print sample size was 6×6 inches. The color density and Lab test were conducted using an X-Rite i1-PRO3 colorimeter. The number of test points was 256 (16×16). The color density was taken as the average of 256 points, and the color difference △E * ab The calculation is based on point 1. The printing substrate is coated paper coating examples 1-4 and coated paper coating comparative examples 1-5. The test results are as follows:.

[0101]

[0102] From the test results, it can be found that the example is close to the effect of DNP original photo paper in terms of color density and color difference. Among them, the base coating affects the flatness of the coating, which can be used to affect the color difference. The dye receiving layer and the heat insulation material in the base coating can be used to improve the color density.

[0103] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-concentration and high-uniformity coated paper coating suitable for thermal sublimation soft label printing, characterized in that: The invention comprises a coated paper substrate, a primer layer and a dye receiving layer which are arranged in sequence; the primer layer is composed of 20 parts of polyurethane, 0.5 parts of silicone resin particles, 0.5 parts of silane coupling agent, 39.5 parts of 2-butanone and 39.5 parts of toluene; the dye receiving layer is composed of 20 parts of vinyl chloride-vinyl acetate copolymer, 0.5 parts of KF-105, 0.5 parts of BYK-322, 39.5 parts of 2-butanone and 39.5 parts of toluene.

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