Adhesive film capable of bonding UV curing ink and preparation method of adhesive film
By introducing an EVA composite adhesive layer into the adhesive tape, the strong hydrogen bonds formed between the hydroxyl and urethane groups and the UV ink are utilized to solve the adhesion problem between the adhesive tape and the UV-cured ink, thereby improving the adhesion performance and heat resistance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-15
- Publication Date
- 2026-03-31
AI Technical Summary
In existing technologies, the adhesion between the adhesive film and the UV-curable ink is low, which leads to weak adhesion and delamination during the heat sealing process of the printed surface, affecting product performance.
The EVA composite adhesive layer is used by polymerizing acrylate monomers with methacrylamide glucose to introduce hydroxyl and urethane groups, forming strong hydrogen bonds with the urethane groups in the UV ink, and adding EVA resin to improve the adhesion performance.
It significantly improves the adhesion and peel strength between the adhesive film and the UV-curable ink, enhances heat resistance and thermal stability, and maintains high peel strength even after high-temperature heat aging.
Smart Images
Figure SMS_4
Abstract
Description
Technical Field
[0001] This invention relates to the field of adhesive technology, specifically to an adhesive film that can bond UV-curable inks and its preparation method. Background Technology
[0002] Adhesives and adhesive tapes are common bonding materials, widely used in heat-sealing UV ink printed surfaces, packaging sealing, automotive manufacturing, and the electronics industry. Among them, acrylic resin adhesives are simple to prepare and have excellent bonding properties, making them important in both daily life and industrial manufacturing. By adding functional monomers, acrylic resin adhesives can be endowed with excellent adhesion, heat resistance, and other properties.
[0003] Heat-sealing UV ink printing surfaces is a common production process in the packaging and labeling industries. However, due to the low surface energy and high chemical inertness of UV inks such as polyurethane acrylates after photocuring and cross-linking, their adhesion to ordinary acrylic resins and other adhesives is poor. This leads to weak adhesion and delamination during heat-sealing of the printed surface, affecting product performance. This invention aims to prepare an adhesive film containing an EVA composite adhesive layer to improve its adhesion to UV ink layers such as polyurethane acrylates. Summary of the Invention
[0004] The purpose of this invention is to provide an adhesive film that can bond UV-curable inks, thereby solving the problem of low adhesion between the adhesive film and the UV-curable ink.
[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: an adhesive film for bonding UV-curable ink and its preparation method, wherein the adhesive film includes a PET film substrate layer, an EVA composite adhesive, and a release film.
[0006] Methods for preparing adhesive films include:
[0007] (1) Add methanol, potassium carbonate, and D-glucosamine hydrochloride to the reaction flask, add methacrylamide chloride dropwise, stir the reaction, filter, distill the filtrate under reduced pressure, separate the crude product by column chromatography, and elute with methanol and dichloromethane solution to obtain methacrylamide glucose. The reaction formula is:
[0008] .
[0009] (2) An alkenyl monomer was added to ethyl acetate to obtain a monomer solution. After stirring, a portion of the monomer solution was added dropwise to a reaction flask, along with a butanol solution of the initiator. The mixture was heated to the reaction temperature and subjected to a prepolymerization reaction under a nitrogen atmosphere. Then, the remaining monomer solution was added to carry out the polymerization reaction. Alkyl isocyanate and dibutyltin dilaurate were added, and the mixture was stirred to carry out the modification reaction. Finally, EVA resin (ethylene-vinyl acetate copolymer) and an antifoaming agent were added. After stirring and cooling, the EVA composite adhesive was obtained. The reaction formula is:
[0010] .
[0011] (3) Apply EVA composite adhesive to the surface of PET film substrate layer, and then cover with a PET release film to obtain an adhesive film that can bond UV curable ink.
[0012] Preferably, in (1), methacryloyl chloride is added dropwise at -10 to 15°C.
[0013] Preferably, (1) the molar amounts of methacryloyl chloride and potassium carbonate are 91% and 144% of the molar amounts of D-glucosamine hydrochloride, respectively.
[0014] Preferably, the stirring reaction time in (1) is 3-4 hours.
[0015] Preferably, in (2), the alkenyl monomer includes methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, and methacrylamide glucose.
[0016] Preferably, the molar amount of the initiator in (2) is 0.6-1.1% of the total molar amount of the alkenyl monomer.
[0017] Preferably, the initiator in (2) is azobisisobutyronitrile or benzoyl peroxide.
[0018] Preferably, in (2), the molar amount of methacrylamide glucose is 2-8% of the total molar amount of alkenyl monomer.
[0019] Preferably, in (2), the molar amounts of alkyl isocyanate and dibutyltin dilaurate are 220-440% and 0.4-1.2% of the molar amounts of methacrylamide glucose, respectively.
[0020] Preferably, the structural formula of the alkyl isocyanate in (2) is as follows: n is any integer between 2 and 6.
[0021] Preferably, the reaction temperature in (2) is 70-80℃ and the prepolymerization reaction time is 30-45min.
[0022] Preferably, the polymerization reaction time in (2) is 4-5 hours.
[0023] Preferably, the temperature during the modification reaction in (2) is 60-80℃ and the reaction time is 3-4h.
[0024] The beneficial technical effects of this invention are as follows: Acrylic ester monomers are polymerized with methacrylamide glucose, and the introduced hydroxyl groups react with alkyl isocyanate esters, then blended with EVA resin to obtain an EVA composite adhesive layer. Finally, this layer is coated onto the surface of a PET film substrate to obtain an adhesive film that can bond with UV-curable inks. This EVA composite adhesive layer contains a large number of hydroxyl and urethane groups. The urethane groups can improve the affinity between the acrylic resin adhesive layer and the polyurethane acrylate containing urethane groups in the UV ink, which is beneficial to improving the adhesion performance between the acrylic resin adhesive layer and the UV ink. Simultaneously, the acrylic resin adhesive layer contains a large number of hydroxyl groups, forming strong hydrogen bond interactions with the polyurethane acrylate, further improving the adhesion performance and peel strength between the two. Furthermore, the acrylic resin adhesive layer contains a heat-resistant furan ring structure, which is beneficial to improving the heat resistance and thermal stability of the acrylic resin adhesive layer, maintaining high peel strength even after high-temperature heat aging. Detailed Implementation
[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0026] Example 1
[0027] (1) Add 120 mL of methanol, 23.16 mmol of potassium carbonate and 20.24 mmol of D-glucosamine hydrochloride to the reaction flask, add 18.53 mmol of methacryloyl chloride dropwise at -15 °C, stir and react for 3 h, filter and distill the filtrate under reduced pressure, separate the crude product by column chromatography, and elute with methanol and dichloromethane solution to obtain methacrylamide glucose.
[0028] (2) Add 350 mmol of methyl acrylate, 630 mmol of butyl methacrylate and 20 mmol of methacrylamide glucose to 150 mL of ethyl acetate to obtain a monomer solution. After stirring, add 40 mL of the monomer solution dropwise into the reaction flask and add 5 mL of n-butanol solution containing 8 mmol of benzoyl peroxide. Heat to 70 °C and carry out a prepolymerization reaction for 45 min under a nitrogen atmosphere. Then add the remaining monomer solution and carry out a polymerization reaction for 5 h. Add 44 mmol of butyl isocyanate and 0.08 mmol of dibutyltin dilaurate. Stir at 70 °C to carry out a modification reaction for 3 h. Finally, add 45 g of EVA resin (ethylene-vinyl acetate copolymer) and 1.1 g of defoamer BYK085. After stirring and cooling, EVA composite adhesive is obtained.
[0029] (3) Apply EVA composite adhesive to the surface of PET film substrate layer, and then cover with a PET release film to obtain an adhesive film that can bond UV curable ink.
[0030] Example 2
[0031] (1) Add 380 mmol of methyl methacrylate, 580 mmol of butyl methacrylate, and 40 mmol of methacrylamide glucose (prepared in Example 1) to 150 mL of ethyl acetate to obtain a monomer solution. After stirring, add 40 mL of the monomer solution dropwise into the reaction flask and add 3 mL of n-butanol solution containing 6 mmol of azobisisobutyronitrile. Heat to 80 °C and carry out a prepolymerization reaction for 30 min under a nitrogen atmosphere. Then add the remaining monomer solution and carry out a polymerization reaction for 4 h. Add 176 mmol of hexyl isocyanate and 0.48 mmol of dibutyltin dilaurate. Stir at 80 °C to carry out a modification reaction for 3 h. Finally, add 58 g of EVA resin and 1.3 g of defoamer BYK085. After stirring and cooling, EVA composite adhesive is obtained.
[0032] (2) Apply EVA composite adhesive to the surface of PET film substrate layer, and then cover with a PET release film to obtain an adhesive film that can bond UV-curable ink.
[0033] Example 3
[0034] (1) Add 270 mmol of methyl methacrylate, 670 mmol of butyl acrylate and 60 mmol of methacrylamide glucose (prepared in Example 1) to 200 mL of ethyl acetate to obtain a monomer solution. After stirring, add 50 mL of the monomer solution dropwise into the reaction flask and add 6 mL of n-butanol solution containing 11 mmol of benzoyl peroxide. Heat to 80 °C and carry out a prepolymerization reaction for 45 min under a nitrogen atmosphere. Then add the remaining monomer solution and carry out a polymerization reaction for 4 h. Add 198 mmol of ethyl isocyanate and 0.48 mmol of dibutyltin dilaurate. Stir at 60 °C to carry out a modification reaction for 4 h. Finally, add 41 g of EVA resin and 1.1 g of defoamer BYK085. After stirring and cooling, EVA composite adhesive is obtained.
[0035] (2) Apply EVA composite adhesive to the surface of PET film substrate layer, and then cover with a PET release film to obtain an adhesive film that can bond UV-curable ink.
[0036] Example 4
[0037] (1) Add 400 mmol of methyl acrylate, 520 mmol of butyl methacrylate and 80 mmol of methacrylamide glucose (prepared in Example 1) to 200 mL of ethyl acetate to obtain a monomer solution. After stirring, add 50 mL of the monomer solution dropwise into the reaction flask and add 6 mL of n-butanol solution containing 10 mmol of benzoyl peroxide. Heat to 70 °C and carry out a prepolymerization reaction for 30 min under a nitrogen atmosphere. Then add the remaining monomer solution and carry out a polymerization reaction for 5 h. Add 352 mmol of butyl isocyanate and 0.96 mmol of dibutyltin dilaurate. Stir at 70 °C to carry out a modification reaction for 4 h. Finally, add 52 g of EVA resin and 1.5 g of defoamer BYK085. After stirring and cooling, EVA composite adhesive is obtained.
[0038] (2) Apply EVA composite adhesive to the surface of PET film substrate layer, and then cover with a PET release film to obtain an adhesive film that can bond UV-curable ink.
[0039] Comparative Example 1
[0040] (1) Add 350 mmol of methyl acrylate and 630 mmol of butyl methacrylate to 150 mL of ethyl acetate to obtain a monomer solution. After stirring, add 40 mL of the monomer solution dropwise into the reaction flask and add 5 mL of n-butanol solution containing 8 mmol of benzoyl peroxide. Heat to 70 °C and carry out a prepolymerization reaction for 45 min under a nitrogen atmosphere. Then add the remaining monomer solution and carry out a polymerization reaction for 5 h. Add 44 mmol of butyl isocyanate and 0.08 mmol of dibutyltin dilaurate. Stir at 70 °C for 3 h. Finally, add 45 g of EVA resin and 1.1 g of defoamer BYK085. After stirring and cooling, EVA composite adhesive is obtained.
[0041] (2) Apply EVA composite adhesive to the surface of PET film substrate layer, and then cover it with a PET release film to obtain adhesive film.
[0042] Comparative Example 2
[0043] (1) Add 350 mmol of methyl acrylate, 630 mmol of butyl methacrylate and 20 mmol of methacrylamide glucose (prepared in Example 1) to 150 mL of ethyl acetate to obtain a monomer solution. After stirring, add 40 mL of the monomer solution dropwise into the reaction flask and add 5 mL of n-butanol solution containing 8 mmol of benzoyl peroxide. Heat to 70 °C and carry out a prepolymerization reaction for 45 min under a nitrogen atmosphere. Then add the remaining monomer solution and carry out a polymerization reaction for 5 h. Finally, add 45 g of EVA resin and 1.1 g of defoamer BYK085, stir and cool to obtain EVA composite adhesive.
[0044] (2) Apply EVA composite adhesive to the surface of PET film substrate layer, and then cover it with a PET release film to obtain adhesive film.
[0045] Comparative Example 3
[0046] (1) Add 350 mmol of methyl acrylate, 630 mmol of butyl methacrylate and 20 mmol of hydroxyethyl acrylate to 150 mL of ethyl acetate to obtain a monomer solution. After stirring, add 40 mL of the monomer solution dropwise into the reaction flask and add 5 mL of n-butanol solution containing 8 mmol of benzoyl peroxide. Heat to 70 °C and carry out a prepolymerization reaction for 45 min under a nitrogen atmosphere. Then add the remaining monomer solution and carry out a polymerization reaction for 5 h. Add 44 mmol of butyl isocyanate and 0.08 mmol of dibutyltin dilaurate. Stir at 70 °C to carry out a modification reaction for 3 h. Finally, add 45 g of EVA resin and 1.1 g of defoamer BYK085. After stirring and cooling, EVA composite adhesive is obtained.
[0047] (2) Apply EVA composite adhesive to the surface of PET film substrate layer, and then cover it with a PET release film to obtain adhesive film.
[0048] Comparative Example 4
[0049] (1) Add 350 mmol of methyl acrylate, 630 mmol of butyl methacrylate and 20 mmol of cyclohexyl methacrylate (CAS Registry No. 101-43-9) to 150 mL of ethyl acetate to obtain a monomer solution. After stirring, add 40 mL of the monomer solution dropwise into the reaction flask and add 5 mL of n-butanol solution containing 8 mmol of benzoyl peroxide. Heat to 70 °C and carry out a prepolymerization reaction for 45 min under a nitrogen atmosphere. Then add the remaining monomer solution and carry out a polymerization reaction for 5 h. Add 44 mmol of butyl isocyanate and 0.08 mmol of dibutyltin dilaurate. Stir at 70 °C to carry out a modification reaction for 3 h. Finally, add 45 g of EVA resin and 1.1 g of defoamer BYK085. After stirring and cooling, EVA composite adhesive is obtained.
[0050] (2) Apply EVA composite adhesive to the surface of PET film substrate layer, and then cover it with a PET release film to obtain adhesive film.
[0051] Mix 100g of UV-cured acrylate polyurethane (model Jining Fangyu Chemical RJ425) with 3g of photoinitiator 1173, pour the mixture into a mold, and cure it in a 2kV UV curing machine for 90s to form a UV-cured ink layer. Then peel off the release film with adhesive film, and bond the UV-cured ink layer with adhesive film to the UV-cured ink layer. Cure at 80℃ for 4h, and test the 180° peel strength according to GB / T 2792-2014 standard.
[0052] The EVA composite adhesive layer with adhesive film was bonded to the UV-cured ink layer, placed in an oven, and heat-aged at 120°C for 72 hours. After cooling to room temperature, the peel strength at 180° was tested.
[0053] Table 1 Performance of Adhesive Film
[0054] The acrylic resin adhesive in the adhesive films prepared in Examples 1-4 contains a large number of hydroxyl and urethane groups. The urethane groups can improve the affinity between the acrylic resin adhesive layer and the polyurethane acrylate containing urethane groups in the UV ink, which is beneficial to improving the adhesion performance between the acrylic resin adhesive layer and the UV ink. At the same time, the large number of hydroxyl groups forms strong hydrogen bond interactions with the polyurethane acrylate, which further improves the adhesion performance and peel strength between the two. In addition, the acrylic resin adhesive layer contains a heat-resistant furan ring structure, which is beneficial to improving the heat resistance and thermal stability of the acrylic resin adhesive layer. Even after high-temperature heat aging, it still has high peel strength. When combined with EVA resin, the resulting adhesive has excellent peel strength, adhesion performance and heat resistance.
[0055] Compared with Example 1, Comparative Example 1 did not add methacrylamide glucose, and the prepared acrylic resin adhesive did not contain hydroxyl groups and could not react with butyl isocyanate. The resulting acrylic ester adhesive did not contain a large number of hydroxyl and urethane groups, resulting in poor adhesion to polyurethane acrylate UV inks, low peel strength, and poor heat resistance and thermal stability of the acrylic resin adhesive layer, with low peel strength retention rate after high-temperature heat aging.
[0056] Comparative Example 2 did not contain butyl isocyanate, and the prepared acrylic resin adhesive did not contain urethane groups, resulting in poor adhesion and low peel strength between it and polyurethane acrylate UV ink.
[0057] The hydroxyethyl acrylate added in Comparative Example 3 contains only one hydroxyl group. The prepared acrylic resin adhesive has very few hydroxyl and urethane groups, resulting in poor adhesion to polyurethane acrylate UV inks, low peel strength, and poor heat resistance and thermal stability of the acrylic resin adhesive layer, with low peel strength retention after high-temperature heat aging.
[0058] The cyclohexyl methacrylate added in Comparative Example 4 does not contain hydroxyl groups and cannot react with butyl isocyanate. The resulting acrylate adhesive does not contain a large number of hydroxyl and urethane groups, resulting in poor adhesion to polyurethane acrylate UV inks and low peel strength.
[0059] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.
Claims
1. An adhesive film for a UV-curable ink, characterized by, The adhesive film comprises a PET film substrate layer, an EVA composite adhesive, and a release film. The preparation method of the EVA composite adhesive layer comprises the following steps: adding an alkenyl monomer into ethyl acetate to obtain a monomer solution, adding part of the monomer solution into a reaction bottle after stirring, and adding a t-butyl alcohol solution of an initiator dropwise, heating to a reaction temperature, and performing a prepolymerization reaction in a nitrogen atmosphere, then adding the remaining monomer solution, performing a polymerization reaction, adding an alkyl isocyanate and dibutyltin dilaurate, stirring to perform a modification reaction, finally adding EVA resin and a defoaming agent, stirring, cooling, and obtaining the EVA composite adhesive. The alkenyl monomer comprises methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, and methacrylamido glucose.
2. The tape film for bondable UV-cured ink according to claim 1, wherein The molar amount of the initiator is 0.6-1.1% of the total molar amount of the alkenyl monomer.
3. The tape film for bondable UV-cured ink according to claim 2, wherein, The initiator is azobisisobutyronitrile or dibenzoyl peroxide.
4. The tape and glue film of the bondable UV-cured ink according to claim 1, wherein, The molar amount of the methacrylamido glucose is 2-8% of the total molar amount of the alkenyl monomer.
5. The tape and glue film of the bondable UV-cured ink according to claim 1, wherein, The molar amounts of the alkyl isocyanate and dibutyltin dilaurate are 220-440% and 0.4-1.2% of the molar amount of the methacrylamido glucose, respectively.
6. The tape and glue film of the bondable UV-cured ink according to claim 5, characterized in that, The preparation method of the methacrylamido glucose comprises the following steps: adding methanol, potassium carbonate, and D-glucosamine hydrochloride into a reaction bottle, adding methacryloyl chloride dropwise at-10 to 15℃, stirring for 3-4h, filtering, and performing vacuum distillation on the filtrate, and then separating the crude product by column chromatography, and eluting with a methanol and dichloromethane solution to obtain the methacrylamido glucose.
7. The tape and glue film of the bondable UV-cured ink according to claim 5, wherein, The alkyl isocyanate has a structural formula of n is any integer between 2 and 6.
8. The tape and glue film of bondable UV-cured ink according to claim 1, wherein, The reaction temperature is 70-80℃, the prepolymerization reaction time is 30-45min, and the polymerization reaction time is 4-5h.
9. The tape and glue film of bondable UV-cured ink according to claim 1, wherein, The modification reaction temperature is 60-80℃, and the reaction time is 3-4h.
10. A method of producing the adhesive film for UV-curable ink as claimed in any one of claims 1 to 9, characterized by, The preparation method comprises the following steps: coating the EVA composite adhesive on the surface of the PET film substrate layer, and then covering a layer of release film to obtain the adhesive film capable of bonding UV curing ink.