EB curing matte coating composition on surface of bubble cap cover film and preparation method of EB curing matte coating composition

Abstract

The invention discloses an EB curing matte coating composition on the surface of a bubble cap cover film and a preparation method of the EB curing matte coating composition, organosilicone modified polyurethane acrylate added in a product formula serves as a functional modified oligomer, and an organosilicone chain segment of the organosilicone modified polyurethane acrylate is migrated to the surface of a coating, so that the surface energy is remarkably reduced on the premise that other properties of the coating are not influenced; the matting agent has the advantages that the matting agent provides excellent smooth hand feeling, the effect of enhancing the whole skin feeling is achieved in the formula, a uniform and fine microscopic rough surface structure is formed in the curing process through the cooperation of the matting agent and a compounding system of the HDDA straight-chain monomer and the CTFA cyclic monomer, and the extreme matting effect is achieved. Besides, the surface migration and enrichment of an organic silicon component (organic silicon modified polyurethane acrylate) are combined with the fine microstructure, so that the coating is endowed with a skin-like smooth touch feeling, and the user experience and the additional value of a terminal product are greatly improved.

Description

Technical Field

[0001] This invention relates to the field of polymer coating technology, specifically to an EB-cured matte coating composition for the surface of a blister pack and its preparation method. Background Technology

[0002] Blister packaging, as an efficient form of product protection and display, has been widely used in cosmetics, pharmaceuticals, food, and electronic components. A typical blister pack consists of a lid film and a forming film heat-sealed together. The lid film is usually a multi-layered composite structure (e.g., from the inside out: heat-sealing layer PE / supporting layer PET / barrier layer AL / outer layer PET). It not only needs excellent heat-sealing and barrier properties, but its outer surface also requires good printability and an aesthetically pleasing visual effect.

[0003] Ink patterns are printed on the outermost PET film layer of the cover film. Traditional processes typically involve coating the PET film layer with a solvent-based protective adhesive after ink printing and then laminating it with a transparent protective film. However, this traditional process has the following drawbacks: 1. Solvent-based adhesives contain a large amount of organic solvents (such as toluene, ethyl acetate, etc.), which will generate significant emissions of volatile organic compounds (VOCs) during the drying and curing process, causing environmental pollution and posing occupational health and safety hazards.

[0004] 2. After the adhesive is applied, it needs to be heated in the oven for a long time to remove the solvent. After the film is coated, it needs to undergo a curing process of 48 to 72 hours to stabilize the performance. The entire production process is long, energy-intensive, and has poor timeliness. Summary of the Invention

[0005] To address the problems of poor adhesion, insufficient scratch resistance, low curing efficiency, and solvent residue in existing coatings on PET composite films and digital ink layers, this invention provides an EB-cured matte coating composition for blister cap films and its preparation method. Through the synergistic effect of the resin system and the EB curing process, the matte coating of blister cap films achieves effects such as low gloss, good hand feel, high production efficiency, no solvent residue, and good scratch and abrasion resistance.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A first aspect of the present invention provides an EB-cured matte coating composition for the surface of a blister pack film, comprising the following components in parts by weight: 5-10 parts by weight of silicone-modified polyurethane acrylate; 50-70 parts by weight of polyester resin; 5-15 parts by weight of adhesion-promoting resin; 5-20 parts by weight of acrylate monomer; Additives: 1-5 parts by weight.

[0007] As a functional modified oligomer, silicone-modified polyurethane acrylate has its silicone segments migrating to the coating surface. Without affecting other properties of the coating, it significantly reduces the surface energy and provides an excellent smooth feel, thus enhancing the overall skin feel in the formulation.

[0008] Furthermore, the polyester resin is a polyester acrylate.

[0009] Polyester acrylate, as the main resin, has excellent adhesion to PET film and digital ink layer, while also providing good coating properties such as resistance to steel wool, hand sweat, and alcohol.

[0010] Furthermore, the adhesion-promoting resin is pure acrylic resin.

[0011] Pure acrylic resin has excellent affinity and wetting properties for PET and ink layers. It can penetrate deeper and bond with the substrate, further enhancing the adhesion of the base resin (polyester acrylate).

[0012] Further, the acrylate monomer is 1,6-hexanediol diacrylate monomer (HDDA) and / or cyclotrimethylolpropane methyl acetal acrylate monomer (CTFA).

[0013] More preferably, the acrylate monomer is a mixture of 1,6-hexanediol diacrylate monomer and cyclotrimethylolpropane methyl acetal acrylate monomer in a weight ratio of (1-3):1.

[0014] The fineness of the matte finish essentially depends on the uniformity, regularity, and size of the micro-uneven structure of the coating surface. Rough and uneven microstructures can lead to a rough feel, uneven gloss, and even a cheap appearance. The combination of HDDA and CTFA is precisely for the purpose of precisely controlling the formation of this surface microstructure.

[0015] HDDA linear monomers have high activity, high shrinkage, and high crosslinking density. As a bifunctional monomer, it has high reactivity and rapidly forms a crosslinking network during curing. Its linear structure makes its molecular chains relatively mobile, but strong crosslinking will quickly lock the molecular chains, and its high polymerization shrinkage rate will generate large internal stress in the early stage of curing.

[0016] CTFA cyclic monomers have low shrinkage, large steric hindrance, and can regulate reaction rates. As a monofunctional monomer, its reaction rate is relatively slow. The cyclic structure in its molecule generates huge steric hindrance, which not only reduces its own polymerization rate, but also affects the movement and arrangement of its surrounding molecular chains (including HDDA and oligomers).

[0017] When the two are combined, during the curing process (especially the UV-LED pre-curing and 172nm surface curing stages), HDDA reacts rapidly first, forming a preliminary cross-linked network framework. CTFA, due to its steric hindrance and slower reactivity, to some extent blocks or interferes with the excessively rapid and uniform network formation dominated by HDDA. This difference in reactivity and polymerization rate results in a moderate and controllable microphase separation at the microscale. This microphase separation is not macroscopic (which would lead to coating defects), but rather the formation of microregions with slightly different cross-linking densities at the nanometer to micrometer scale. This microregion structure provides a richer and more uniform template for the positioning of matting agents and the shaping of the final surface micro-roughness.

[0018] During the leveling and pre-curing process of the coating, the coexistence of two monomers with different surface tensions will generate micro-convection according to the Maragoni effect. This micro-convection helps to break the flocculation of matting powder, making it more evenly distributed in the coating. At the same time, the slow reaction of CTFA gives it more time to migrate and interact with the organosilicon additives that migrate to the surface, jointly and finely controlling the chemical environment of the outermost layer of the coating, thus forming a more uniform wrinkling effect when treated with 172nm excimer lamp.

[0019] HDDA contributes to high hardness and scratch resistance, but a pure HDDA system tends to be brittle and has a hard, slippery feel. CTFA's ring-like structure provides a certain degree of rigidity, while its monofunctionality reduces crosslinking density and introduces more hinge points, giving the network a degree of microscopic flexibility. The cured network formed by the combination of these two is a perfect blend of rigidity and flexibility. This balanced network ensures that the microscopic protrusions created by the matte powder and curing wrinkles are neither too soft to be easily worn down (ensuring durability) nor too hard and brittle to produce debris or a rough feel when scratched. When a finger glides over them, these uniform, firm yet slightly elastic microscopic protrusions provide a sophisticated, smooth feel, rather than a harsh, abrasive texture.

[0020] The core principle of the combination of CTFA and HDDA lies in utilizing the differences between the two in polymerization reaction kinetics, surface properties and final network structure to create a controllable, nanoscale micro-uniformity during the curing process. This micro-uniformity works perfectly with the matte powder and the 172nm excimer curing process to ultimately create a high-end matte surface with extremely low gloss and a delicate and uniform feel.

[0021] Furthermore, the additives include photoinitiators, leveling agents, and matting agents.

[0022] The addition of matte powder achieves a matte finish on the coating. It creates microscopic inhomogeneities in the coating, which scatter light when it hits the surface of the coating, thereby reducing specular reflection and achieving low gloss.

[0023] A second aspect of the present invention also provides a method for preparing the above-mentioned EB-cured matte coating composition, comprising the following steps: S1. Weigh the raw materials of the above formula, and stir and disperse the raw materials except for the matting powder. S2. While stirring and dispersing, slowly add matte powder and continue stirring to mix evenly to obtain EB-cured matte coating; S3. Plasma treatment is performed on the surface of the PET composite film; S4. Apply EB-cured matte coating to the surface of the treated PET composite film; S5. UV-LED pre-curing, 172nm excimer surface curing and electron beam curing are performed sequentially to form a matte coating on the surface of the PET composite film.

[0024] Furthermore, the PET composite film is a PET film layer printed with digital ink.

[0025] Compared with the prior art, the present invention has the following beneficial effects: (1) The silicone-modified polyurethane acrylate added to the product formulation is a functional modified oligomer. Its silicone segments migrate to the coating surface, significantly reducing the surface energy without affecting other properties of the coating, providing an excellent smooth feel, and enhancing the overall skin feel in the formulation.

[0026] (2) Through the synergistic effect of matte powder and the "HDDA linear monomer + CTFA cyclic monomer" compound system, a uniform and delicate micro-rough surface structure is formed during the curing process, achieving an ultimate matte effect. In addition, the surface migration and enrichment of the organosilicon component (organosilicon-modified polyurethane acrylate), combined with the above-mentioned delicate microstructure, gives the coating a skin-like smooth feel, greatly improving the user experience and added value of the end product.

[0027] (3) By selecting appropriate types of acrylate oligomers, acrylate monomers, and matting agents, and then using a three-step curing process of LED pre-curing, excimer surface curing, and finally electron beam curing, the problems of poor adhesion, insufficient scratch resistance, and slow curing on PET composite films and digital ink layers were solved. This resulted in a matte coating for blister cap films with low gloss, good hand feel, fast production efficiency, no solvent residue, good scratch and wear resistance, and strong adhesion. Compared with ordinary UV matte oils, this EB-cured matte oil has the characteristics of low viscosity, no solvent, good matte effect, good chemical resistance, and good wear resistance. Attached Figure Description

[0028] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0029] Figure 1 This is a photograph of a matte coating formed on a PET composite film with digital ink printed on its surface, as shown in Example 1. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Examples 1-4 Examples 1-4 provide an EB-cured matte coating composition for the surface of a blister cap film and its preparation process.

[0032] The raw material composition of the EB-cured matte coating composition in the above embodiments is as follows: Polyester acrylate (M303); Organosilicon-modified polyurethane acrylate (BN43203); Pure acrylic resin (PP2203); The acrylate monomers are 1,6-hexanediol diacrylate monomer and cyclotrimethylolpropane methyl acetal acrylate monomer. The additives include photoinitiator (Igracure184), photoinitiator (TMO), leveling agent (BYK3510), and matting agent (E1011).

[0033] The preparation process of the EB-cured matte coating in the above embodiments is as follows: S1. Weigh the raw materials of the above formula, and stir and disperse the raw materials except for the matting powder at a speed of 800 rpm. S2. While stirring and dispersing, slowly add matte powder and continue stirring and mixing evenly for about 1 hour to obtain EB cured matte coating; S3. Plasma treatment of PET composite film with digital ink printed on the surface to 42 dynes. S4. Apply EB-cured matte coating to the surface of the treated PET composite film using a roller coating method, with a coating amount of 5 g / m². 2 The unwinding speed of the PET composite film is 10 m / min; S5, proceed in sequence: UV-LED pre-curing (600 mJ / cm) 2 ); 172nm excimer surface curing (200mJ / cm) 2 (Oxygen content <200ppm); EB curing (100 KeV, 100 Kgy) ultimately forms a matte coating on the surface of the PET composite film.

[0034] Figure 1 The image shown is a physical photograph of the matte coating formed on the PET composite film with digital ink printed on its surface, as described in Example 1. It can be seen that the coating successfully covers the underlying digital ink pattern, giving the printed pattern a high-end matte texture and enhancing the overall appearance and visual appeal of the packaging. The coating surface exhibits a deep, soft, and uniform extremely low gloss, and the entire coating is free of any visible orange peel, pinholes, uneven coloring, or graininess, displaying a silky, delicate, and uniform visual texture.

[0035] The specific raw materials and amounts of the EB-cured matte coating compositions in each embodiment are shown in Table 1.

[0036] Table 1. Raw materials and amounts (parts by weight) of the EB-cured matte coating compositions in Examples 1-4 raw material Example 1 Example 2 Example 3 Example 4 Polyester acrylate 64.4 50 70 68 BN43203 8.6 10 8 5 Pure acrylic resin 8.6 15 10 5 HDDA 8.6 10 3.75 10 CTFA 4.3 10 1.25 5 Matte powder 3.4 3 4.5 4.5 Igracure184 0.9 0.75 1 1 TMO 0.9 0.75 1 1 Leveling agent 0.3 0.5 0.5 0.5 Comparative Examples 1-9 Comparative Examples 1-9 are comparative test examples of Example 1. The raw materials and amounts of the EB-cured matte coating composition were adjusted, as shown in Table 2. The preparation process of each comparative example is the same as that of Example 1.

[0037] Table 2. Raw materials and amounts (parts by weight) of the EB-cured matte coating compositions in Comparative Examples 1-9 raw material Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Polyester acrylate 0 73 64.4 64.4 73 64.4 64.4 73.25 55.3 Polyurethane acrylate 64.4 0 0 0 0 0 0 0 0 BN43203 8.6 0 8.6 8.6 8.6 8.6 8.6 8.6 8.6 Pure acrylic resin 8.6 8.6 8.6 8.6 0 8.6 8.6 8.6 8.6 HDDA 8.6 8.6 12.9 0 8.6 6 10 2.7 15 CTFA 4.3 4.3 0 12.9 4.3 6.9 2.9 1.35 7.5 Matte powder 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 Igracure184 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 TMO 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 Leveling agent 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 The coatings prepared in each embodiment and comparative example were subjected to performance tests, and the test results are shown in Tables 3 and 4.

[0038] Table 3 Performance test results of the coatings in each embodiment and comparative example project Example 1 Example 2 Example 3 Example 4 Viscosity (cps) 330 300 650 310 Apparent Level 5 Level 4 Level 4 Level 5 Gloss (60°) <5 <5 <5 <5 Adhesion 5B 2B 5B 4B Steel wool pass Not approved pass pass Smooth feel Level 5 Level 5 Level 4 3+ Alcohol resistance test pass pass pass pass Water resistance test pass pass pass pass Resistant to artificial sweat (no change on surface after 48 hours) pass Not approved pass pass Table 4 Performance test results of the coatings in each comparative example project Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Viscosity (cps) 350 310 310 350 340 340 310 580 300 Apparent Level 5 Level 5 Level 3 Level 3 Level 5 Level 5 Level 5 Level 4 Level 5 Gloss (60°) <5 <5 <5 <5 <5 <5 <5 <5 <5 Adhesion 3B 5B 5B 5B 4B 5B 4B 5B 2B Steel wool pass pass pass pass pass pass pass pass Not approved Smooth feel Level 5 Level 4 3+ 3+ Level 5 Level 4 Level 4 3+ Level 5 Alcohol resistance test pass pass pass pass pass pass pass pass pass Water resistance test pass pass pass pass pass pass pass pass pass Resistant to artificial sweat (no change on surface after 48 hours) pass pass pass pass pass pass pass pass Not approved Viscosity testing conditions: Brookfield viscometer, 25°C.

[0039] Appearance test: The coating surface is observed by the naked eye to see if it is fine and uniform, and whether there are any spots. The evaluation level is 1-5.

[0040] specific: Level 5: The surface is extremely fine and uniform, with a consistent color, and no unevenness, pinholes, orange peel texture, or graininess.

[0041] Level 4: The surface is fine and uniform, with only minor defects visible at specific angles.

[0042] Level 3: The surface has visible slight unevenness or minor defects.

[0043] Grade 2: The surface has obvious mottled, orange peel-like, or uneven appearance.

[0044] Grade 1: The surface has serious defects such as shrinkage cavities and mottling.

[0045] (The final result is the consensus or average of multiple assessments).

[0046] The adhesion test standard is ASTM D3359.

[0047] The test standard for steel wool resistance is as follows: using a reciprocating abrasion tester, steel wool is fixed on the friction head of the test arm, a load of 750g is applied to the coated sample, and the sample is rubbed back and forth for 400 cycles at a frequency of 35 times / minute over a stroke of 100mm.

[0048] Evaluation criteria: After the test, clean the surface with a soft cloth and observe it under a standard light source. If the coating surface shows no obvious loss of gloss or the coating exposes the substrate, it is judged as "passed".

[0049] The testing standard for smoothness is as follows: personnel test the feel of the coating, and the evaluation level is 1-5.

[0050] Multiple evaluators used their fingertips to touch the coating surface back and forth with constant pressure and speed in a constant temperature and humidity environment (23±2°C, 50±5%RH).

[0051] Rating criteria: Level 5: Extremely smooth to the touch, like silk or skin, with no stickiness.

[0052] Level 4: Smooth to the touch, but slightly less refined than Level 5.

[0053] Level 3: The feel is average, with a slight damping sensation.

[0054] Level 2: Rough to the touch, with noticeable resistance.

[0055] Level 1: The texture is very rough or sticky.

[0056] (The final result is the arithmetic mean of multiple ratings).

[0057] Alcohol resistance test: Immerse in 99.5% alcohol at 50℃ for 14 days and observe whether there is any change in the surface coating. If there is no change, it is judged as "passed".

[0058] Water resistance test: Immerse in 50℃ water for 14 days and observe whether there is any change in the surface coating. If there is no change, it is judged as "passed".

[0059] Artificial sweat resistance test: Immerse the sample in artificial sweat at room temperature for 48 hours and observe whether there is any change in the surface coating. If there is no change, it is judged as "pass".

[0060] The test results in Table 1 show that: Compared with Comparative Example 1 and Example 1, the adhesion of the main resin, polyurethane acrylate, was significantly reduced compared with M303.

[0061] Compared with Example 1, Comparative Example 2 did not contain silicone-modified polyurethane acrylate BN43203, and its smooth feel was significantly reduced.

[0062] Comparative Examples 3 and 2, using HDDA and CTFA alone, showed slightly less matte finish than the results achieved by using HDDA and CTFA together in the examples, indicating that the combination of HDDA and CTFA has a synergistic effect on matte finish.

[0063] Compared with Example 1, Comparative Example 5 did not contain pure acrylic resin PP2203, and its adhesion was significantly reduced.

[0064] The test results from the examples show that the EB-cured matte varnish prepared by the present invention has good adhesion, abrasion resistance, alcohol resistance, water resistance, and hand sweat resistance, which meets the performance requirements of the cover film matte coating.

[0065] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An EB-cured matte coating composition for the surface of a blister pack film, characterized in that, The components include the following parts by weight: 5-10 parts by weight of silicone-modified polyurethane acrylate; 50-70 parts by weight of polyester resin; 5-15 parts by weight of adhesion-promoting resin; 5-20 parts by weight of acrylate monomer; Additives: 1-7 parts by weight.

2. The EB-cured matte coating composition according to claim 1, characterized in that, The polyester resin is polyester acrylate.

3. The EB-cured matte coating composition according to claim 1, characterized in that, The adhesion-promoting resin is pure acrylic resin.

4. The EB-cured matte coating composition according to claim 1, characterized in that, The acrylate monomer is 1,6-hexanediol diacrylate monomer and / or cyclotrimethylolpropane methyl acetal acrylate monomer.

5. The EB-cured matte coating composition according to claim 4, characterized in that, The acrylate monomers are 1,6-hexanediol diacrylate monomers and cyclotrimethylolpropane methyl acetal acrylate monomers in a weight ratio of (1-3):

1.

6. The EB-cured matte coating composition according to claim 1, characterized in that, The additives include photoinitiators, leveling agents, and matting agents.

7. A method for preparing an EB-cured matte coating composition as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Weigh the raw materials of the above formula, and stir and disperse the raw materials except for the matting powder. S2. While stirring and dispersing, slowly add matte powder and continue stirring to mix evenly to obtain EB-cured matte coating; S3. Plasma treatment is performed on the surface of the PET composite film printed with digital ink. S4. Apply EB-cured matte coating to the surface of the treated PET composite film; S5. UV-LED pre-curing, 172nm excimer surface curing and electron beam curing are performed sequentially to form a matte coating on the surface of the PET composite film.

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