Ultraviolet-cured self-repairing transfer printing adhesive and preparation method thereof
By introducing self-healing acrylate oligomers and hydrazone bonds into the UV-curable transfer adhesive, the problem of irreversible damage after scratching is solved, achieving self-healing function and improving the durability and reliability of the coating.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-20
- Publication Date
- 2026-04-10
AI Technical Summary
Existing UV-curable transfer adhesives are prone to scratches after being scratched, leading to irreversible damage and loss of their protective and decorative functions.
By employing self-healing acrylate oligomers and introducing acylhydrazone bonds, the coating can self-repair under heating conditions after scratching. The reversible exchange and recombination of acylhydrazone bonds are used to reconstruct the molecular structure.
It significantly extends the service life of the coating, maintains the decorative effect and protective performance, and enhances the practical value and reliability of the product.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of photocurable materials and relates to a UV-curable self-healing transfer adhesive and its preparation method. Background Technology
[0002] UV-curable transfer printing technology involves applying a textured film to a substrate coated with adhesive, pressing it with rollers, and then curing it under UV light. After peeling off the film, the fine textured structure can be copied to different substrates. UV-curable transfer adhesive can be applied via dispensing or screen printing, and the textured film can be transferred to surfaces such as glass, PC, and PET. UV-curable transfer adhesive is primarily used for the exterior protection and decoration of consumer electronics, and can also be used in automobiles and home appliances, such as back covers for 3C electronic products, protective cases, and automotive trim parts. The UV-curable transfer printing process is characterized by its simplicity, high efficiency, energy saving, and environmental friendliness.
[0003] Existing UV-curable transfer adhesives used for the protection and decoration of consumer electronics do not have self-healing capabilities. Once these adhesives are severely scratched, they are prone to developing scratches. As these scratches accumulate and deepen, they eventually cause irreversible damage to the adhesive. At this point, the non-self-healing UV-curable transfer adhesive loses its protective and decorative functions. Summary of the Invention
[0004] To address the aforementioned technical problems in the prior art, this invention provides a UV-curable self-healing transfer adhesive, which possesses good hardness, wear and scratch resistance, and excellent self-healing function.
[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: One objective of this invention is to provide a UV-curable self-healing transfer adhesive, comprising, by weight, the following raw materials: 40-60 parts of self-healing acrylate oligomer; 10-20 parts of polyurethane acrylic resin; 20-30 parts of acrylic reactive diluent; 1-5 parts of free radical photoinitiator; Furthermore, the self-healing acrylate oligomer is a rubber-modified acrylate, and its molecular structure contains acylhydrazone bonds.
[0006] Furthermore, the molecular structure of the self-healing acrylate oligomer is as follows: ; Where n = 20 to 80.
[0007] Furthermore, the preparation method of the self-healing acrylate oligomer includes the following steps: S1. An aromatic compound with a dihydrazine group is subjected to hydrazinolysis with a diester to obtain synthetic product 1; S2. Synthetic product 1 is condensed with a double-terminated amino polymer to obtain synthetic product 2. S3. The synthesized product 2 is subjected to an end-capping reaction with the isocyanate-hydroxy acrylate adduct to obtain the self-healing acrylate oligomer.
[0008] Further, in step S1, the aromatic compound having a dihydrazine group is bis(2-styryl)methanedihydrazine, and the diester is dimethyl terephthalate; the molar ratio of bis(2-styryl)methanedihydrazine to dimethyl terephthalate is 1:(1.5-2.5), preferably 1:2; the hydrazinolysis reaction is carried out in the presence of a catalyst at 80-120°C for 1-5 hours, preferably at 100°C for 3 hours.
[0009] Further, in step S1, the catalyst is p-toluenesulfonic acid (p-TsOH), and the amount of the catalyst is 0.01% to 0.1% of the total mass of the reactants. Preferably, the amount of the catalyst is 0.03% of the total mass of the reactants.
[0010] The reaction formula for step S1 is as follows: .
[0011] Further, in step S2, the main chain of the diamino-terminated polymer is any one of polybutadiene, polyisoprene, or hydrogenated polybutadiene. Preferably, the diamino-terminated polymer is poly(1,4-butadiene)-diamino. The molar ratio of the diamino-terminated polymer to the synthetic product 1 is (1.5-2.5):1, preferably 2:1. The condensation reaction is a Schiff base reaction, and the condensation reaction is carried out in the presence of a catalyst at 30-60°C for 3-6 hours, preferably at 50°C for 5 hours.
[0012] Further, in step S2, the catalyst is p-toluenesulfonic acid (p-TsOH), and the amount of the catalyst is 0.01%-0.05% of the total mass of the reactants. Preferably, the amount of the catalyst is 0.03% of the total mass of the reactants.
[0013] The reaction formula for step S2 is as follows: ; Where n = 20 to 80.
[0014] Further, in step S3, the isocyanate-hydroxyacrylate adduct is prepared by reacting isophorone diisocyanate with hydroxyethyl acrylate; the molar ratio of the isocyanate-hydroxyacrylate adduct to the synthetic product 2 is (1.5-2.5):1, preferably 2:1; the end-capping reaction is carried out in the presence of a catalyst at 50-80°C for 1-5 hours, preferably at 60°C for 3 hours.
[0015] Further, in step S3, the catalyst is di-n-butyltin dilaurate (DBTDL), and the amount of the catalyst is 0.01% to 0.1% of the total mass of the reactants. Preferably, the amount of the catalyst is 0.03% of the total mass of the reactants.
[0016] The reaction formula for step S3 is as follows:
[0017] ; Where n = 20 to 80.
[0018] Furthermore, the polyurethane acrylic resin is selected from one or more of trifunctional, tetrafunctional, pentafunctional, or hexafunctional polyurethane acrylic resins.
[0019] Furthermore, the acrylic reactive diluent includes one or a mixture of several of the following: pentaerythritol triacrylate (PETA), 3,3,5-trimethylcycloethyl acrylate (TMCHA), trimethylolpropane trimethacrylate (TMPTMA), 2-phenoxyethyl acrylate (PHEA), trimethylolpropane triacrylate (TMPTA), isobornyl acrylate (IBOA), tricyclodecanediethanol diacrylate (TCDDA), dicyclopentenyl acrylate (DCPA), dipentaerythritol hexaacrylate (DPHA), cyclotrimethylolpropane methyl acetal acrylate (CTFA), dicyclopentenyl ethoxy acrylate (DCPEA), and methyl 2-acrylate (tetrahydro-2-furanyl) (THFA).
[0020] Furthermore, the free radical photoinitiator is one or a mixture of several of the following brands: DETX (2,4-diethylthioxanthone), TPO (2,4,6-trimethylbenzoyl diphenylphosphine oxide), 184 (1-hydroxycyclohexylbenzophenone), 651 (α,α'-dimethylbenzoyl ketal), 819 (bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide), 369 (2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone), and 907 (2-methyl-1-(4-methylmercaptophenyl)-2-morpholino-1-propanone).
[0021] The second objective of this invention is to provide a method for preparing the above-mentioned UV-curable self-healing transfer adhesive, comprising the following steps: Step 1: Add the free radical photoinitiator and acrylic reactive diluent to a container and stir until dissolved and homogeneous; Step 2: Add the self-healing acrylate oligomer and polyurethane acrylic resin, and stir to mix evenly; Step 3: Vacuum degassing and seal packaging.
[0022] Compared with the prior art, the beneficial effects of the present invention are: The UV-curable self-healing transfer adhesive prepared in this invention introduces acylhydrazone bonds with dynamic and reversible properties into the self-healing acrylate oligomer, giving the cured coating a significant self-healing function. When the coating surface is damaged by external forces such as scratches, the internal acylhydrazone bonds can undergo reversible exchange and recombination under heating conditions, promoting the self-adjustment and reconstruction of the molecular structure. This effectively repairs microcracks and scratches, overcoming the shortcomings of traditional UV-curable transfer adhesives, which are prone to leaving scratches after severe scratching, leading to irreversible damage as the scratches accumulate and deepen. This significantly extends the service life of the coating, maintains its decorative appearance and surface protection performance for a long time, and greatly enhances the practical value and reliability of the product in consumer electronics, automobiles, and home appliances. Detailed Implementation
[0023] The present invention will be described below with reference to examples. These examples are only used to explain the present invention and are not intended to limit the scope of the present invention.
[0024] Synthesis example The preparation of self-healing acrylate oligomers includes the following steps: (1) Under nitrogen protection, 2 mol of dimethyl terephthalate (DMT) was first added to a three-necked flask equipped with a stirrer and a heating device. Then, 1 mol of bis(2-styryl)methanedihydrazine was slowly added to the three-necked flask. Then, 0.03% of p-toluenesulfonic acid (p-TsOH) based on the total mass of the reactants was added as a catalyst. The reaction was carried out at 100°C for 3 h to obtain the synthetic product 1.
[0025] (2) Under nitrogen protection, 2 mol of poly(1,4-butadiene)-diamino was added to a three-necked flask. 1 mol of the synthetic product 1 was slowly added dropwise to the three-necked flask, and 0.03% of p-toluenesulfonic acid (p-TsOH) of the total mass of the reactants was added as a catalyst. The reaction was carried out at 50°C for 5 h to obtain the synthetic product 2.
[0026] (3) Under nitrogen protection, 2 mol of the adduct IPDI-HEA, prepared by pre-reaction of isophorone diisocyanate (IPDI) and hydroxyethyl acrylate (HEA) in a 1:1 molar ratio, was placed in a three-necked flask. 1 mol of the synthesized product 2 was slowly added dropwise to the three-necked flask, and 0.03% of DBTDL by mass of the total reactants was added as a catalyst. The reaction was carried out at 60°C for 3 h to obtain the self-healing acrylate oligomer.
[0027] Example 1 A UV-curable self-healing transfer adhesive, the preparation method of which includes the following steps: (1) Add 20g of PETA, 5g of PHEA, 2g of free radical photoinitiator 651, and 1g of free radical photoinitiator TPO to a double planetary mixer in sequence and stir at 500r / min for 2h. (2) After the above steps are dissolved and stirred evenly, add 40g of self-healing acrylate oligomer, 15g of trifunctional polyurethane acrylic resin (Changxing, brand name DR-U010), and 5g of hexafunctional polyurethane acrylic resin (Changxing, brand name 66197H) in sequence; stir at 500r / min for 1h.
[0028] (3) After stirring evenly, evacuate to a vacuum degree of -0.10MPa and seal the package.
[0029] Example 2 A UV-curable self-healing transfer adhesive, the preparation method of which includes the following steps: (1) Add 15g of IBOA, 5g of DCPA, 2.5g of free radical photoinitiator 184, and 0.3g of free radical photoinitiator DETX to a double planetary mixer in sequence, and stir at 700r / min for 1.5h. (2) After the above steps are dissolved and stirred evenly, add 45g of self-healing acrylate oligomer, 15g of tetrafunctional polyurethane acrylic resin (Changxing, brand 6165), and 3g of pentafunctional polyurethane acrylic resin (Changxing, brand 6170D) in sequence and stir at 600r / min for 1h.
[0030] (3) After stirring evenly, evacuate to a vacuum degree of -0.06MPa and seal the package.
[0031] Example 3 A UV-curable self-healing transfer adhesive, the preparation method of which includes the following steps: (1) Add 10g of CTFA, 10g of DCPEA, 5g of TMPTA, 1.5g of free radical photoinitiator 369, and 0.5g of free radical photoinitiator 819 to a double planetary mixer in sequence, and stir at 800r / min for 1 h. (2) After the above steps are dissolved and stirred evenly, add 50g of self-healing acrylate oligomer, 10g of tetrafunctional polyurethane acrylic resin (Changxing, brand 6165), and 5g of pentafunctional polyurethane acrylic resin (Changxing, brand 6170D) in sequence; stir at 800r / min for 1h.
[0032] (3) After stirring evenly, evacuate to a vacuum degree of -0.07MPa and seal the package.
[0033] Example 4 A UV-curable self-healing transfer adhesive, the preparation method of which includes the following steps: (1) Add 20g of TMPTMA, 5g of TMCHA, 2.0g of free radical photoinitiator 651, and 1.0g of free radical photoinitiator 369 to a double planetary mixer in sequence and stir at 1000r / min for 1h. (2) After the above steps are dissolved and stirred evenly, add 55g of rubber modified acrylate, 10g of trifunctional polyurethane acrylic resin (Changxing, brand name DR-U010), and 8g of pentafunctional polyurethane acrylic resin (Changxing, brand name 6170D) in sequence; stir at 1000r / min for 0.5h.
[0034] (3) After stirring evenly, evacuate to a vacuum degree of -0.08MPa and seal the package.
[0035] Example 5 A UV-curable self-healing transfer adhesive, the preparation method of which includes the following steps: (1) Add 20g of TMPTMA, 5g of TMCHA, 1.0g of free radical photoinitiator TPO, and 1842.0g of free radical photoinitiator to a double planetary mixer in sequence, and stir at 1000r / min for 1h. (2) After the above steps are dissolved and stirred evenly, add 60g of rubber modified acrylate, 6g of tetrafunctional polyurethane acrylic resin (Changxing, brand 6165), and 8g of hexafunctional polyurethane acrylic resin (Changxing, brand 6197H) in sequence; stir at 1000r / min for 0.5h.
[0036] (3) After stirring evenly, evacuate to a vacuum degree of -0.08MPa and seal the package.
[0037] Comparative Example 1 A UV-curable transfer adhesive, the preparation method of which includes the following steps: (1) Add 20g of PHEA, 5g of TMCHA, 5g of TMPTA, 2.5g of free radical photoinitiator 184, and 0.5g of free radical photoinitiator ITX to a double planetary mixer in sequence, and stir at 1000r / min for 1h. (2) After the above steps are dissolved and stirred evenly, add 40g of 6363 (15-18 functionality, polyester type) from Changxing Company, 10g of trifunctional polyurethane acrylic resin (Changxing, brand name DR-U010), and 8g of pentafunctional polyurethane acrylic resin (Changxing, brand name 6170D) in sequence; stir at 1000r / min for 0.5h.
[0038] (3) After stirring evenly, evacuate to a vacuum degree of -0.08MPa and seal the package.
[0039] Comparative Example 2 A UV-curable transfer adhesive, the preparation method of which includes the following steps: (1) Add 10g of IBOA, 10g of TMCHA, 15g of THFA, 2.5g of free radical photoinitiator 651, and 0.5g of free radical photoinitiator DETX to a double planetary mixer in sequence, and stir at 800r / min for 1 h. (2) After the above steps are dissolved and stirred evenly, add 50g of DM588 (10-functionality, polyurethane acrylate) from Double Bond Company, 10g of tetrafunctional polyurethane acrylate resin (Changxing, brand name 6165), and 5g of pentafunctional polyurethane acrylate resin (Changxing, brand name 6170D) in sequence; stir at 800r / min for 1h.
[0040] (3) After stirring evenly, evacuate to a vacuum degree of -0.07MPa and seal the package.
[0041] Comparative Example 3 A UV-curable transfer adhesive, the preparation method of which includes the following steps: (1) Add 10g of PHEA, 15g of DCPEA, 5g of THFA, 2.0g of free radical photoinitiator 369, and 1.0g of free radical photoinitiator 184 to a double planetary mixer in sequence, and stir at 700r / min for 1.5h. (2) After the above steps are dissolved and stirred evenly, add 60g of SC2152 (15-functionality, polyurethane acrylate) from Meiyuan Company, 15g of tetrafunctional polyurethane acrylate resin (Changxing, brand 6165), and 3g of pentafunctional polyurethane acrylate resin (Changxing, brand 6170D) in sequence; stir at 600r / min for 1h.
[0042] (3) After stirring evenly, evacuate to a vacuum degree of -0.06MPa and seal the package.
[0043] The performance of the UV-curable self-healing transfer adhesive of the present invention was tested through the following experiments.
[0044] The adhesives obtained in Examples 1-5 and Comparative Examples 1-3 were applied to a clean glass plate, covered with a textured film, and rolled flat before photocuring. The photocuring conditions were: light intensity 1000 mW / cm². 2 The light exposure time was 2 seconds. After peeling off the textured film, the cured coating was tested as follows, and the results are shown in Table 1.
[0045] The adhesives obtained in Examples 1-5 and Comparative Examples 1-3 were subjected to the following tests: (1) Pencil hardness: The test is conducted according to the method of "GB / T 6739-2022 Pencil method for determining the hardness of paint film". H represents hardness, and the number represents the grade. The larger the number, the higher the hardness.
[0046] (2) Adhesion: The adhesion was tested according to the method of GB / T 9286-2021 Paints and Varnishes Cross-cut Test. The results were divided into 6 levels: 0, 1, 2, 3, 4 and 5. The smaller the number, the better the adhesion.
[0047] (3) Abrasion resistance grade: The test was conducted according to GB / T 1768-2006 "Determination of abrasion resistance of paints and varnishes by rotating rubber grinding wheel method". The results were divided into 4 grades: I, II, III and IV. The smaller the number, the higher the abrasion resistance grade.
[0048] (4) Self-repair rate: After being scratched by a blade, the product is kept at 80°C for 2 hours, and the ratio of its elongation at break to its initial elongation at break is measured.
[0049] Table 1. Performance comparison of adhesives in Examples 1-5 and Comparative Examples 1-3
[0050] As shown in Table 1, the coatings of all embodiments exhibit good hardness (2H-3H), excellent adhesion (0-1 grade), and high abrasion resistance (I-II grade).
[0051] Examples 1-5 all showed a self-healing rate of 70%-87%, proving that the dynamic reversible bonds introduced in this invention effectively functioned. Furthermore, as the content of the self-healing oligomer increased from 40 parts to 60 parts, the self-healing rate increased (from 70% to 87%). In contrast, Comparative Examples 1-3 used conventional high-functionality resins, which, although possessing certain hardness and wear resistance, had no self-healing function whatsoever (self-healing rate of 0%).
[0052] In summary, this invention successfully introduces self-healing functionality into high-performance UV-curable transfer adhesives, achieving self-healing properties without sacrificing their traditional mechanical and performance characteristics, thus significantly improving the product's durability and reliability.
[0053] 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 principles of the present invention should be included within the protection scope of the present invention.
Claims
1. An ultraviolet light cured self-repairing transfer glue, characterized in that, The raw materials include, by weight parts: Self-repairing acrylate oligomer 40-60 parts; Polyurethane acrylic resin 10-20 parts; Acrylic active diluent 20-30 parts; Radical photoinitiator 1-5 parts.
2. The UV-cured self-repairing transfer tape of claim 1, wherein, The self-repairing acrylate oligomer is a rubber-modified acrylate, which contains an acylhydrazone bond in the molecular structure.
3. The UV-cured self-repairing transfer tape of claim 2, wherein, The preparation method of the self-repairing acrylate oligomer includes the following steps: S1, hydrazinolysis reaction of an aromatic compound with double hydrazine groups and a dibasic acid ester to obtain a synthesis product 1; S2, condensation reaction of the synthesis product 1 and a double-end amino polymer to obtain a synthesis product 2; S3, end-capping reaction of the synthesis product 2 and an isocyanate-hydroxyl acrylate adduct to obtain the self-repairing acrylate oligomer.
4. The UV-cured self-repairing transfer tape of claim 3, wherein, In step S1, the aromatic compound with double hydrazine groups is bis(2-styryl)methane dihydrazine, and the dibasic acid ester is dimethyl terephthalate; the molar ratio of bis(2-styryl)methane dihydrazine to dimethyl terephthalate is 1:1.5-2.5; the hydrazinolysis reaction is carried out in the presence of a catalyst at 80-120°C for 1-5 hours.
5. The UV-cured self-repairing transfer tape of claim 3, wherein, In step S2, the main chain of the double-end amino polymer is any one of polybutadiene, polyisoprene or hydrogenated polybutadiene; the molar ratio of the double-end amino polymer to the synthesis product 1 is 1.5-2.5:1; the condensation reaction is a Schiff base reaction, and the condensation reaction is carried out in the presence of a catalyst at 30-60°C for 3-6 hours.
6. The UV-cured self-repairing transfer tape of claim 3, wherein, In step S3, the isocyanate-hydroxyl acrylate adduct is prepared by reacting isophorone diisocyanate and hydroxyethyl acrylate; the molar ratio of the isocyanate-hydroxyl acrylate adduct to the synthesis product 2 is 1.5-2.5:1; the end-capping reaction is carried out in the presence of a catalyst at 50-80°C for 1-5 hours.
7. The UV-cured self-repairing transfer tape of claim 1, wherein, The polyurethane acrylic resin is selected from one or more of trifunctional, tetrafunctional, pentafunctional or hexafunctional polyurethane acrylic resins.
8. The UV-cured self-repairing transfer tape of claim 1, wherein, The acrylic active diluent is selected from one or more of pentaerythritol triacrylate, 3,3,5-trimethylcyclohexyl acrylate, trimethylolpropane trimethacrylate, 2-phenoxyethyl acrylate, trimethylolpropane trimethacrylate, isobornyl acrylate, tricyclodecane dimethanol diacrylate, dicyclopentenyl acrylate, dipentaerythritol hexaacrylate, cyclotrimethylolpropane formal acrylate, dicyclopentenyl ethoxy acrylate, and 2-acryloyl(tetrahydro-2-furyl)methyl methylate.
9. The UV-cured self-repairing transfer tape of claim 1, wherein, The radical photoinitiator is selected from one or more of 2,4-diethylthioxanthone, 2,4,6-trimethylbenzoyldiphenyl phosphine oxide, 1-hydroxycyclohexyl phenyl ketone, α,α'-dimethylbenzil ketal, bis(2,4,6-trimethylbenzoyl)phenyl phosphine oxide, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, and 2-methyl-1-(4-methylmercaptophenyl)-2-morpholin-1-propanone.
10. A process for the preparation of an ultraviolet light-cured self-repairing transfer adhesive according to any one of claims 1 to 9, characterized in that, The method includes the following steps: Step one: Add free radical photoinitiator and acrylic reactive diluent into a container, stir until dissolved uniformly; Step two: Add self-repairing acrylate oligomer and polyurethane acrylic resin, stir until mixed uniformly; Step three: Vacuum degassing, seal packaging.