Cigarette pack wear-resistant UV (ultraviolet) gloss oil for highlight PET (polyethylene terephthalate) base material as well as preparation method and use method thereof

Abstract

The invention discloses a formula, a preparation method and a use method of cigarette pack wear-resistant UV (ultraviolet) gloss oil for a highlight PET (polyethylene terephthalate) base material. The coating is prepared from 50 parts of 1, 6-hexanediol diacrylate, 25 parts of epoxy resin, 10 parts of polyurethane resin, 8 parts of trimethylolpropane triacrylate, 3 parts of 1-[4-(2-hydroxyethoxy) phenyl]-2-hydroxy-2-methyl-1-acetone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl) butanone 3692, 1 part of an auxiliary agent I, 0.9 part of an auxiliary agent II and 0.1 part of 3-p-hydroxyanisole. The UV gloss oil is prepared from various components through a conventional preparation method, and when the UV gloss oil is used, the surface of a high-brightness PET base film is bottomed with isolation ink, and then the wear-resistant UV gloss oil is printed to form a UV gloss oil layer. The UV gloss oil with modified nitrocellulose polymer resin as a main body and additives as an auxiliary agent is adopted, the UV gloss oil and the isolation bottoming ink layer on the highlight PET base film layer are subjected to a cross-linking reaction in the production process, a cured film layer is formed to improve protection of the ink layer of the product, and friction resistance and high temperature resistance can be achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of cigarette label packaging printing, and relates to a wear-resistant UV varnish for use on a high-gloss PET substrate and a preparation method thereof, and also relates to a use method of the wear-resistant UV varnish for use on a high-gloss PET substrate. Background Art

[0002] Competition in the domestic cigarette market is intensifying day by day. Price wars and advertising campaigns are constantly squeezing the profit margins of products. Improving production efficiency and optimizing production processes are the keys for enterprises to cope with competition. Among them, increasing the cigarette packing speed has become one of the important means for major cigarette enterprises to enhance their competitiveness. A certain China National Tobacco Industry Co., Ltd. has successively introduced multiple groups of ZJ119-ZB416 high-speed cigarette packing equipment, increasing the cigarette packing speed of slender cigarettes from the original 300 packs per minute to more than 580 packs per minute. However, with the increase in production speed, the inadaptability of the existing cigarette label production process to high-speed cigarette packing has gradually emerged. Among them, for the strip and box packaging papers of Guiyan (Kuayue), a high-gloss PET film is coated with deep black and then aluminized and then laminated with 200g reel white cardboard. After the original paper is printed, the appearance is very flat and bright. During the cigarette packing production process, even slight scratches between the cigarette label and the equipment will be particularly obvious on the pure black bottom surface, seriously affecting the appearance quality of the product. Customers require the printing factory to improve the process and enhance the wear-resistant function of the existing cigarette label materials to meet the requirements of high-speed cigarette packing for this product.

[0003] UV varnish ink, also known as "ultraviolet varnishing" or "curing varnishing", refers to a UV varnish composed of a photosensitive resin, an active diluent, a photoinitiator and additives. Under the irradiation of ultraviolet light with a certain wavelength, free radicals of the photoinitiator in the system initiate the unsaturated double bonds in the resin, and a chain polymerization reaction occurs rapidly, causing it to crosslink and form a film and cure. Its advantages are fast varnishing speed, the curing reaction can be completed instantaneously, the film layer has high brightness, the film surface is relatively firm after drying, and it has good mechanical, heat-resistant, cold-resistant, water-resistant, wear-resistant and other properties, and has a good protective effect. The surface of the printed matter is bright and smooth, and the refractive effect can make the graphics and texts produce a strong three-dimensional sense, the colors are more vivid, and the printed matter has a high-class feeling. At present, the "Guiyan" series and "Huangguoshu" series of cigarette labels have all adopted the UV varnishing process to protect the products. The existing UV varnish layer is colorless and transparent, and can resist a certain degree of frictional external force during the forming process. However, when it encounters sharp hard paper scraps and glue particles in the cigarette machine during the cigarette packing process, it is easy to be scratched, forming dark streaks, which are very obvious on the high-brightness pure black PET bottom paper.

[0004] In the industry, the gravure UV varnish commonly used has an epoxy acrylate ultraviolet photosensitive resin as the main body, contains a certain proportion of solvents (15 - 20%), and contains an appropriate amount of toluene to increase the erosion effect on the surface of the printing substrate (soft plastic printing process). However, due to the strict safety and hygiene standards for cigarette label products that benzene series substances are not allowed to be used (content ≤ 0.02mg), the traditional ink materials cannot meet the requirements of the R & D and production of this project. The scratch rate of the UV varnish prepared with the traditional formula is as high as 15% at the speed of 680 packs per minute on the high-speed cigarette packing machine. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: to provide a cigarette label wear-resistant UV varnish for high-gloss PET substrates, a preparation method and a usage method, so as to ensure that there are no scratches, streaks and other damages on the appearance surface during the production and use of the product on the high-speed cigarette packing machine.

[0006] The technical solution adopted by the present invention is: a cigarette label wear-resistant UV varnish for high-gloss PET substrates, including the following components and their mass ratios:

[0007] 1,6 - hexanediol diacrylate 50

[0008] Epoxy resin 25

[0009] Polyurethane resin 10

[0010] Trimethylolpropane triacrylate 8

[0011] 1 - [4 - (2 - hydroxyethoxy)phenyl] - 2 - hydroxy - 2 - methyl - 1 - propanone 3

[0012] 2 - benzyl - 2 - dimethylamino - 1 - (4 - morpholinophenyl)butanone 369 2

[0013] Auxiliary agent 1 1

[0014] Auxiliary agent 2 0.9

[0015] 3 - p - methoxyphenol 0.1.

[0016] A preparation method of a wear-resistant UV varnish for cigarette labels applicable to high-gloss PET substrates, the method comprising: mixing 1,6-hexanediol diacrylate, epoxy resin, polyurethane resin, trimethylolpropane triacrylate, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone 369 and 3-p-methoxyphenol uniformly according to the ratio, and then adding auxiliary agent 1 (organosilicon leveling agent) and auxiliary agent 2 (nano-silica matting agent with a particle size of 30-50 nm) according to the ratio, and uniformly mixing to obtain the wear-resistant UV varnish, wherein the mixing temperature is controlled at 40±2°C, the stirring speed is 2000 rpm, vacuum degassing treatment is carried out for 30 minutes, and a particle size analyzer is used to monitor the dispersion degree, D90≤5μm.

[0017] A method for using a wear-resistant UV varnish for cigarette labels on high-gloss PET substrates, the method comprising the steps:

[0018] A. Substrate pretreatment: Applying a primer of isolation ink on the surface of the high-gloss PET substrate

[0019] B. Printing the UV varnish layer: Then printing the wear-resistant UV varnish on the surface after the primer of isolation ink to form a UV varnish layer;

[0020] C. Three stages of UV curing: Curing the formed UV varnish layer.

[0021] Furthermore, the above isolation ink layer comprises the following components and their mass ratios:

[0022] 2-Cellulose acetate 55

[0023] 3-Acrylic ester copolymer 17

[0024] 4-n-Propyl acetate 10

[0025] 5-Butanone 8

[0026] 6-Ethyl acetate 7.5

[0027] 7-Propylene glycol methyl ether 2

[0028] 8-Auxiliary agent 0.5;

[0029] Mix 2-cellulose acetate, 3-acrylic ester copolymer, 4-n-propyl acetate, 5-butanone, 6-ethyl acetate, 7-propylene glycol methyl ether uniformly according to the ratio, and then add 8-auxiliary agent according to the ratio, and uniformly mix to obtain the isolation ink.

[0030] Further, the screen ruling of the UV varnish plate used above is 100-110% of the screen ruling of the ordinary color group ink plate, and the cell depth is 15-17um, that is, the cell depth is 80% of the ink plates of other color groups. 9. Further, the above uses 200g high-bulk thick white cardboard with single-sided adhesive, and the performance indicators are: stiffness > 110mN·m, dirt count < 0.70 per m 2 , glossiness > 50% and moisture content 6.0-7.5%.

[0031] Further, the above-mentioned gravure plate for UV varnish is characterized in that a laser engraving gravure plate for UV varnish is used for operation, with a screen ruling of 100-110L and a cell depth of 15-17um.

[0032] The beneficial effects of the present invention: Compared with the prior art, the present invention uses a UV varnish with modified nitrocellulose-based polymer resin as the main body and additives as the auxiliary. During production, it undergoes a cross-linking reaction with the isolation ink layer on the high-brightness PET base film layer. The introduction of polyurethane resin can improve the flexibility of the film layer, form an interpenetrating network structure with epoxy resin, and form a friction-resistant cured film layer to improve the protection of the product, which can reduce the formation of white streaks caused by scratching during high-speed cigarette wrapping production, and the scratch rate of the varnish used in the present invention can be reduced to less than 0.5%.

[0033] The test results show that for the products produced using the new varnish formula, under the detection of a wear-resistant testing instrument, for samples with a length of 20mm * 100mm, under a pressure of 2N, and continuously rubbed 30 times, the surface of the finished product is basically not damaged, and various functional indicators such as the brightness and anti-friction of the finished product fully meet the expected technical requirements of the project.

[0034] Adopting an isolation ink undercoating process on the surface of the high-brightness PET base film improves the adhesion fastness of the surface layer of the material, promotes the bonding and curing strength between the UV varnish layer and the surface of the high-brightness PET base film, and enhances the anti-friction ability of the finished product. After comparison, the undercoating treatment does not affect the appearance effect of the product, the deviation of the product brightness value △L ≤ 1.0, and the wear resistance is improved by ≥ 95%. Detailed implementation manners

[0035] Figure 1 It is the power diagram of the LED UV lamp tube for IST;

[0036] Figure 2 It is the contact angle test diagram of the original sample and Hanghua black ink. In the figure, (a) is the original sample and (b) is the standard sample;

[0037] Figure 3 It is the contact angle test diagram of the original sample and Hanghua white ink. In the figure, (a) is the original sample and (b) is the standard sample;

[0038] Figure 4It is a test diagram of the contact angle between the sample and water. In the figure, (a) is the original sample and (b) is the standard sample;

[0039] Figure 5 It is the effect diagram of the scratching test after the sample is taken out after being placed in an oven at 100 °C for 5 minutes. In the figure, (a) is the original sample and (b) is the standard sample;

[0040] Figure 6 It is the effect diagram of the scratching test after the sample is taken out after being placed in an oven at 110 °C for 5 minutes. In the figure, (a) is the original sample and (b) is the standard sample;

[0041] Figure 7 It is the effect diagram of the scratching test after the sample is taken out after being placed in an oven at 120 °C for 5 minutes. In the figure, (a) is the original sample and (b) is the standard sample. Specific implementation mode

[0043] The present invention will be further introduced below in combination with specific embodiments.

[0044] Example 1: A wear-resistant UV varnish for cigarette labels on high-gloss PET substrates, including the following components and their mass ratios:

[0045] 1,6-Hexanediol diacrylate 50 kg

[0046] Epoxy resin 25 kg

[0047] Polyurethane resin 10 kg

[0048] Trimethylolpropane triacrylate 8 kg

[0049] 1-[4-(2-Hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propanone 3 kg

[0050] 2-Benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone 369 2 kg

[0051] Auxiliary agent 1 1 kg

[0052] Auxiliary agent 2 0.9 kg

[0053] 3-p-Hydroxyanisole 0.1 kg;

[0054] Preparation method of abrasion-resistant UV varnish for cigarette label using high-gloss PET substrate. The method is as follows: Mix 1,6-hexanediol diacrylate, epoxy resin, polyurethane resin, trimethylolpropane triacrylate, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone 369, and 3-methoxyphenol evenly according to the ratio. Then add auxiliary agent 1 (silicone leveling agent) and auxiliary agent 2 (nano-silica matting agent with particle size of 30 - 50 nm) according to the ratio, and mix evenly to obtain the abrasion-resistant UV varnish. Among them, the mixing temperature is controlled at 40 ± 2 °C, the stirring speed is 2000 rpm, vacuum degassing treatment is carried out for 30 minutes, and a particle size analyzer is used to monitor the dispersion degree, with D90 ≤ 5 μm.

[0055] The main technical parameters of the varnish are as follows:

[0056]

[0057] Research on the drying suitability of ink: Through investigation, it is determined that one theory holds that when the surface of UV ink is irradiated by too much ultraviolet light, it will become harder and harder. When printing another layer of ink on this hardened ink film and performing the second drying, the adhesion between the upper ink layer and the lower ink layer will become very poor. Another theory holds that over-curing will cause photo-oxidation on the surface of the ink. The occurrence of photo-oxidation will break the chemical bonds on the surface of the ink film. If the molecular bonds on the surface of the ink film degenerate or are damaged, its adhesion to another ink layer will decrease. The over-cured ink film is not only less flexible but also prone to surface embrittlement.

[0058] Corresponding comparative tests were carried out. Practical experience shows that the most obvious phenomena of UV ink or varnish when irradiated excessively are hardening and embrittlement. When printing UV ink + UV on-line varnishing, the problem of over-drying of UV ink will be involved, directly affecting the adhesion of the varnish. When many products need to print two layers of white ink or overprint two spot colors (such as the barcode position of the tested Guiyan Kuayue, where the original process printed four layers of white ink), it is necessary to pay attention to the fact that if the previous color ink is over-dried, it will affect the adhesion of the subsequent color ink.

[0059] Through testing, confirm the drying suitability of the ink and varnish:

[0060] 1. After printing with UV ink, fold the paper and observe whether the ink layer cracks and peels off at the folded part after flattening.

[0061] 2. Use a manual cutter to cut the paper and observe whether the ink or varnish peels off at the edge of the cut surface.

[0062] 3. Use a similar indentation line roller to press hard on the paper surface. After folding along the indentation line, observe whether the ink peels off at the crease.

[0063] Example 2: A method for using a wear-resistant UV varnish for cigarette labels applicable to high-gloss PET substrates, the method comprising the steps of:

[0064] A. Substrate pretreatment: Apply a primer treatment with isolation ink on the surface of the high-gloss PET substrate

[0065] B. Printing the UV varnish layer: Then print the wear-resistant UV varnish on the surface after primer treatment with isolation ink to form a UV varnish layer;

[0066] C. Three stages of UV curing: Cure the formed UV varnish layer.

[0067] Currently, there are mainly two methods for printing UV inks in the domestic cigarette label printing industry. One is to print graphics and texts in-line and then apply UV varnish separately with a resin plate offline (such as Shantou Zhuangli), and the other is to print graphics and texts in-line + apply UV varnish in-line (the original process of Guizhou Jinjia). Each of these two process methods has its own advantages. However, on the high-brightness PET base film, especially in its blank areas, when the transparent UV varnish is directly printed without any printing ink covering or isolating, surface scratching will occur during the production and use of high-speed cigarette packing machines. Especially during high-speed production, the local temperature rises due to product friction, and the surface layer of the cigarette label made of PET substrate shows a phenomenon of thermal melting and softening, resulting in product scratching.

[0068] Through research and experiments, applying a primer process with isolation ink on the surface of the high-brightness PET base film improves the adhesion fastness of the surface layer of the material, promotes the bonding and curing of the UV varnish layer with the surface of the high-brightness PET base film, and enhances the anti-friction ability of the finished product. After comparison, the primer treatment in this case does not affect the appearance effect of the product. The deviation of the product brightness value △L ≤ 1.0, and the wear resistance is improved by ≥ 90%. This innovative technology is used for the first time in the domestic cigarette label industry.

[0069] Furthermore, the above isolation ink layer comprises the following components and their mass ratios:

[0070] 2 - Cellulose acetate 55 kg

[0071] 3 - Acrylate copolymer 17 kg

[0072] 4 - n-Propyl acetate 10 kg

[0073] 5 - Methyl ethyl ketone 8 kg

[0074] 6 - Ethyl acetate 7.5 kg

[0075] 7 - Propylene glycol methyl ether 2 kg

[0076] 8 - Auxiliary agent 0.5 kg;

[0077] After uniformly mixing 2-cellulose acetate, 3-acrylate copolymer, 4-n-propyl acetate, 5-butyl methyl ketone, 6-ethyl acetate, and 7-propylene glycol methyl ether according to the ratio, add 8-additive according to the ratio, and uniformly mix to obtain the isolation ink. Adjust the proportion of the acrylate copolymer to 25 kg, and the wear resistance is tested to decrease by 15%.

[0078] Through the improvement of the gravure drying system, the UV curing effect is ensured: the printing substrate to be printed is a high-brightness PET base film with a pure black bottom surface, which almost completely absorbs ultraviolet light. Therefore, the drying power required is greater than that in conventional printing production. It is found in the test that for the high-brightness black PET base film material tested, only UV with a wavelength exceeding 320 μm can pass through, resulting in the drying and curing effect on the underlying ink. The conventional UV mercury lamp (the main energy is in the UV-C band, 100 - 280 nm) on the original equipment is greatly affected in drying effect during the test. After identifying the reason, the LED UV lamp tube of IST is replaced, and its wavelength range is 200 - 450 nm, which just meets the test requirements, as Figure 1 shown.

[0079] Furthermore, the screen ruling of the UV varnish plate used for the above printing is 100 - 110% of the screen ruling of the ink plate of the ordinary color unit, and the cell depth is 15 - 17 μm, that is, the cell depth is 80% of the ink plate of other color units. The general UV varnishing process requires the screen ruling of the plate making to be 130% of the screen ruling of the ink plate of other color units, and the engraving depth is 50% of the ink plate of other color units. Therefore, the varnish layer is very thin. To meet the technical requirements of this project, the screen ruling of the UV varnish plate used is 110% of the screen ruling of the ink plate of the ordinary color unit, and the engraving depth is 80% of the ink plate of other color units. The product effect printed has no significant difference from the product without base coating and varnishing.

[0080] Use single-sided adhesive 200g high-bulk white cardboard, and the performance indicators are respectively: stiffness > 110 mN·m, dirt count < 0.70 pieces / m 2 , glossiness > 50% and moisture content 6.0 - 7.5%. The determination method for the selection of the performance indicators of this white cardboard is as follows:

[0081] The original process used ordinary white cardboard + UV varnish for production, and it could only maintain normal production of 2,500 - 3,000 sheets, and then gradually showed uneven surface with pits and bumps, and the wear and scratch resistance was poor.

[0082] Cause analysis: The surface of the composite PET material is rough, which directly affects the leveling performance of the UV varnish on the paper surface. When the paper surface is too rough, the flow rate of the UV varnish on the paper surface is slow, causing the film-forming substance in the UV varnish, the photosensitive resin, to cure rapidly. After UV curing, the gloss and brightness of the printed matter surface are not good, and it will also affect the reflection, diffraction, and interference of UV light, resulting in UV light attenuation and affecting the curing effect.

[0083] Solution: Select paper with good printing suitability. After testing,

[0084] Select Shandong Sun single-sided adhesive 200g high-bulk thick white cardboard. The experimental results meet the requirements of ink leveling.

[0085] Laser engraving UV varnish gravure plate operation, screen line 100 - 110L, cell depth 15 - 17um. The determination of this improvement method is as follows:

[0086] Glossiness test of the varnish engraving plate development and products. At the initial stage of the test, the glossiness of the surface of the underprinted products is exactly the same as that of the products produced without underprinting. However, during the continuous production of 10,000 - 15,000 sheets, the glossiness of the product surface gradually decreases, and the printed surface of the product becomes significantly dull and loses the gloss effect.

[0087] Cause analysis: Uneven coating of UV varnish is directly related to the varnish plate, printing pressure, anilox roll, etc. The difference in the consistency of the relief height on the surface of the gravure plate will affect the transfer of the varnish, thus affecting the coating quality of the varnish; uneven printing pressure will also affect the transfer of the varnish to the paper, resulting in uneven thickness of the UV varnish transferred to the paper surface; since the paper surface is prone to shedding paper dust before varnishing, the paper dust accumulates and blocks the cells after a period of production, making the ink storage amount on the surface of the anilox roll uneven, thus resulting in insufficient transfer of the UV varnish to the paper surface and affecting the glossiness of the product surface.

[0088] Solution: By adjusting the laser engraving plate-making parameters, ensure the consistency of the relief height on the surface of the gravure plate; adjust the printing pressure to ensure its moderation and stability; thoroughly clean the anilox roll to ensure that there is no foreign matter remaining in the cells, and add a fine mesh filter device to filter during the circulation of the UV varnish in the ink tank.

[0089] The plate-making process parameters are as follows:

[0090] Increased isolation layer UV varnish gravure plate Original UV varnish gravure plate 110L, 15um 120L, 13um Laser engraving Mechanical engraving

[0091] Reform of the drying system for the gravure printing unit: Whether the drying of the UV varnish is thorough directly affects the film-forming effect of the ink and is crucial for the wear resistance of the finished product. Since a primer layer for isolating the ink is added between the UV varnish layer and the PET substrate, special drying treatment technology is required. The UV system of the Cerutti gravure printing machine was re-developed and designed. The specific plan was to add three groups of domestic Zhongshan UV ultraviolet lamps for drying treatment in front of the original printing and drying system between the Cerutti PU-09 station and the slitting unit. The first group has one UV lamp tube, with a spacing of 0.8 m - 1.5 m from the second group. The second group is next to the third group, and both have 2 - 5 UV lamp tubes, with the lamp tube power being 15 - 18 KW.

[0092] Research on the heating and filtering process of UV varnish: In order to quickly and thoroughly dry the UV varnish layer, the varnish at room temperature was heated before being put on the machine to ensure that the active molecules in the varnish increased their fluidity and ensured rapid drying. However, correspondingly, during large-scale high-speed production, some ink molecules would polymerize in advance to form large particles during the ink back-pumping cycle, affecting the flatness of the printing surface and damaging the printing resistance of the gravure plate. After testing, it was determined that the old UV varnish needed to be filtered before it could be used again.

[0093] Solution: The ink suction pump of the gravure UV varnish circulation ink tank is already equipped with a filtering device, but it cannot fully achieve the filtering purpose. After analysis, it is related to the photosensitizer additives in the varnish, which are prone to condensation reactions in a static state. In this case, a heating device was added to the ink barrel. During production, the UV varnish was heated to 50 °C and its reciprocating circulation was promoted by the ink suction pump, basically solving the problem.

[0094] Comparative test on the hydrophilic and lipophilic properties of the ink and the heat resistance of the product

[0095] 1. Test method

[0096] (1) Hydrophilic and lipophilic property test: Different inks were respectively dropped on two samples (the unqualified original sample, abbreviated as the original sample; the qualified standard sample, abbreviated as the standard sample) to test their contact angles, and the wetting data of the two samples with the ink were obtained. Then, distilled water was respectively dropped on the two samples to test their contact angles, and the hydrophilic data of the samples with water were obtained.

[0097] (2) Thermal stability test: The unqualified original sample and the qualified standard sample were put into an oven together, and the temperature was set at three temperature conditions of 100 °C, 110 °C, and 120 °C for 5 minutes each. After taking them out, Taber abrasion resistance test was carried out according to GB / T 1768 - 2006. A hard metal rod was quickly used to scrape the surfaces of the two samples, and the scratches and peeling of the surface ink were checked, and photos were taken for comparison.

[0098] 2. Test data

[0099] (1) Hydrophilic-lipophilic data, such as Figure 2 - 3 shown, and the comparison data of the contact angle between the samples in Table 1 and the ink. (2)

[0101] Table 1 Contact angle between samples and ink

[0102] Number Sample Contact angle at 1s / ° 1 Original sample of Hanghua black 54.329 2 Standard sample of Hanghua black 49.916 3 Original sample of Hanghua white 58.462 4 Standard sample of Hanghua white 44.118

[0103] From Figure 2 , Figure 3 and Table 1, it can be seen that the contact angle between the original sample and the ink is significantly larger than that between the standard sample and the ink. The larger the contact angle, the worse the compatibility between the two. Here, it can be seen that the compatibility between the standard sample and the ink is better than that of the original sample.

[0104] Table 2 Contact angle between samples and water

[0105] Number Sample Contact angle at 1s / ° 5 Original sample of water 53.565 6 Standard sample of water 65.054

[0106] From Figure 4 and Table 2, it can be seen that the contact angle between the original sample and water is smaller than that between the standard sample and water. To sum up, the original sample has better hydrophilicity and poorer lipophilicity, while the standard sample has better lipophilicity and poorer hydrophilicity.

[0107] (2) Thermal stability data of the samples

[0108] 1) Samples at 100 °C for 5 min, such as Figure 5 shown;

[0109] 2) Samples at 110 °C for 5 min, such as Figure 6 shown;

[0110] 3) Samples at 120 °C for 5 min, such as Figure 7 shown;

[0111] From Figure 5 it can be seen that when placed at 100 °C for 5 min, when the ink on both samples is scratched with a hard metal rod, the ink can maintain good integrity and will not fall off. When the temperature rises to 110 °C and is placed for 5 min, the ink layer of the original sample will fall off when scratched with a hard metal rod. And as the temperature continues to rise to 120 °C, the ink coating is more likely to fall off under the scratching of the hard metal rod, and this ink falling-off phenomenon occurs from the bottom layer of the ink, directly exposing the PET bottom plate. So it is considered that the thermal stability of the bottom layer of the ink is poor, and the fundamental reason is the poor wear resistance of the original formulated ink. However, the improved standard sample still cannot be scratched off the surface of the printed layer with a hard metal rod when the temperature rises to 110 °C and 120 °C. Therefore, its wear resistance can withstand the friction of the high-speed cigarette machine.

[0112] 3. Test conclusion

[0113] The summary based on the above analysis is as follows: Incomplete drying and curing of the UV ink layer will affect the wear resistance. It is necessary to replace the UV lamp for irradiation and ensure the irradiation power and duration to ensure complete curing of the bottom UV ink and the surface UV varnish ink layer. After adding the priming process, the thermal stability and wear resistance of the product's UV varnish layer have been greatly improved.

[0114] As described above, the above is only a specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A wear-resistant UV varnish for cigarette labels on high-gloss PET substrates, characterized in that, It includes the following components and their mass ratios: 1,6 - hexanediol diacrylate 50 Epoxy resin 25 Polyurethane resin 10 Trimethylolpropane triacrylate 8 1 - [4 - (2 - hydroxyethoxy)phenyl] - 2 - hydroxy - 2 - methyl - 1 - propanone 3 2 - benzyl - 2 - dimethylamino - 1 - (4 - morpholinophenyl)butanone 369 2 Auxiliary agent 1 1 Auxiliary agent 2 0.9 3 - p - methoxyphenol 0.

1.

2. The preparation method of a wear-resistant UV varnish for cigarette labels used for high-gloss PET substrates according to claim 1, wherein, The method is as follows: Mix 1,6 - hexanediol diacrylate, epoxy resin, polyurethane resin, trimethylolpropane triacrylate, 1 - [4 - (2 - hydroxyethoxy)phenyl] - 2 - hydroxy - 2 - methyl - 1 - propanone, 2 - benzyl - 2 - dimethylamino - 1 - (4 - morpholinophenyl)butanone 369 and 3 - p - methoxyphenol evenly according to the ratio, and then add Auxiliary agent 1 and Auxiliary agent 2 according to the ratio. After mixing evenly, a wear - resistant UV varnish is prepared. Among them, the polyurethane resin and the epoxy resin form an interpenetrating network structure.

3. The preparation method of a wear-resistant UV varnish for cigarette labels using a high-gloss PET substrate according to claim 2, characterized in that, Auxiliary agent 1 uses an organosilicon leveling agent, and Auxiliary agent 2 uses a nano - silica matting agent with a particle size of 30 - 50 nm.

4. The method of using a kind of abrasion-resistant UV varnish for cigarette labels on high-gloss PET substrates prepared according to claim 2, characterized in that, The method includes the steps: A. Substrate pretreatment: Apply a primer of isolation ink on the surface of the high - gloss PET substrate B. Printing the UV varnish layer: Then print the wear - resistant UV varnish on the surface after the isolation ink primer to form a UV varnish layer; C. Three - stage UV curing: Cure the formed UV varnish layer.

5. The method for using a wear-resistant UV varnish for cigarette labels on a high-gloss PET substrate according to claim 4, characterized in that, The isolation ink layer includes the following components and their mass ratios: 2 - cellulose acetate 55 3 - acrylate copolymer 17 4 - n - propyl acetate 10 5 - butanone 8 6 - ethyl acetate 7.5 7 - propylene glycol methyl ether 2 8 - auxiliary agent 0.5; Mix 2 - cellulose acetate, 3 - acrylate copolymer, 4 - n - propyl acetate, 5 - butanone, 6 - ethyl acetate, 7 - propylene glycol methyl ether evenly according to the ratio, and then add 8 - auxiliary agent according to the ratio. After mixing evenly, an isolation ink is prepared; the mixing temperature is controlled at 40 ± 2 °C, the stirring speed is 2000 rpm, vacuum degassing treatment is carried out for 30 minutes, and a particle size analyzer is used to monitor the dispersion degree, and the dispersion degree D90 ≤ 5 μm.

6. The method for using a wear-resistant UV varnish for cigarette labels on a high-gloss PET substrate according to claim 4, characterized in that The screen ruling of the UV varnish plate used for printing the UV varnish layer is 100 - 110% of the screen ruling of the ordinary color group ink printing plate, and the cell depth is 15 - 17 μm.

7. A method for using a wear-resistant UV varnish for cigarette labels on a high-gloss PET substrate according to claim 4, characterized in that, The high-gloss PET substrate uses single-sided self-adhesive 200g high-bulk white cardboard, and the performance indicators are respectively: stiffness > 110 mN·m, dirt count < 0.70 pieces / m 2 , gloss > 50%, and moisture content 6.0 - 7.5%.

8. The method for using a wear-resistant UV varnish for cigarette labels on a high-gloss PET substrate according to claim 4, characterized in that, The UV varnish plate uses a laser - engraved UV varnish gravure plate.

Images