An adhesive composition for a decorative film and a decorative film

Abstract

The application relates to the field of adhesives, and specifically discloses an adhesive composition for a decorative film and the decorative film. The adhesive composition for the decorative film comprises the following components in parts by weight: 52-58 parts of a methyl methacrylate-butyl acrylate-hydroxyethyl acrylate terpolymer, 6-7 parts of 3-(triethoxysilyl)propyl methacrylate, 3.5-4.5 parts of an N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate complex monomer, 12-14 parts of a terpene phenolic resin, 9-11 parts of a hydrogenated petroleum resin, and 2-3 parts of a polyisobutylene resin; and a preparation method thereof comprises the following steps: raw material pretreatment, base glue preparation, resin mixing, additive addition, crosslinking regulation and control, and post-treatment. The composition / product of the application can be used for adhesive bonding of the decorative film, and has the effects of being suitable for various substrates without changing the formula, improving the compatibility of the adhesive for various substrates, adhesive stability and long-term use reliability.

Description

Technical Field

[0001] This application relates to the field of adhesives, and more specifically, to an adhesive composition for decorative films and decorative films. Background Technology

[0002] Decorative films, as materials that combine aesthetics and functionality, are widely used in furniture surface decoration, building door and window cladding, and electronic device casing beautification. They rely on adhesives to tightly bond the substrate layer to the decorative wood grain layer, and the performance of the adhesive directly determines the adhesive strength, long-term stability, and applicable scenarios of the decorative film. With the diversification of decorative film applications, the market is placing higher demands on its compatibility with substrates, its resistance to environmental aging, and its service life. Adhesives, as a key supporting material, have become a core element affecting the performance upgrade of decorative films.

[0003] Traditional adhesives are mostly single-substrate-to-single-formula. For example, PVC uses acrylic pressure-sensitive adhesive with terpene phenolic resin, which bonds with PVC chlorine atoms through the interaction of polar groups. PP uses modified natural rubber with hydrogenated petroleum resin, and requires corona / sandblasting pretreatment. PET uses siloxane-modified acrylic emulsion with γ-aminopropyltriethoxysilane. They cannot accommodate all three substrates. Changing the substrate requires changing the adhesive, resulting in frequent cleaning of production equipment and high switching costs. Summary of the Invention

[0004] To address the problem that traditional adhesives require changing the adhesive when replacing the substrate, leading to frequent cleaning of production equipment and high switching costs, this application provides an adhesive composition for decorative films and a decorative film.

[0005] This application provides an adhesive composition for decorative films and a decorative film, employing the following technical solution:

[0006] In a first aspect, this application provides a decorative film, which adopts the following technical solution:

[0007] A decorative film includes a substrate layer, an adhesive layer, and a decorative wood grain layer arranged sequentially, wherein the decorative wood grain layer is made of PVC, PP, or PET, and the material of the substrate layer matches the material of the decorative wood grain layer.

[0008] By adopting the above technical solution, since the base adhesive composition provides basic adhesion, specific functional monomers and tackifying resins are used to synergistically adapt to different polarity substrates, crosslinking agents enhance the cohesive strength of the adhesive layer, substrate adaptation additives optimize interfacial bonding, and anti-aging agents and storage stabilizers ensure long-term performance. The system formed by the combination of each component can adapt to a variety of substrates and decorative wood grain layers without changing the formula. Therefore, the effect of improving the multi-substrate compatibility and stability of the adhesive is enhanced.

[0009] Secondly, this application provides an adhesive composition for decorative films, employing the following technical solution:

[0010] An adhesive composition for a decorative film, used in one of the aforementioned decorative films, comprises the following components in parts by weight: 52-58 parts of methyl methacrylate-butyl acrylate-hydroxyethyl acrylate terpolymer, 6-7 parts of 3-(triethoxysilyl)propyl methacrylate, 3.5-4.5 parts of N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate composite monomer, 12-14 parts of terpene phenolic resin, 9-11 parts of hydrogenated petroleum resin, 2-3 parts of polyisobutylene resin, and hexamethylene diisocyanate. The composition includes 1.2-1.8 parts of cyanate trimer, 0.8-1.2 parts of bisphenol A diglycidyl ether, 0.1-0.2 parts of dibutyltin dilaurate, 1.3-1.7 parts of γ-aminopropyltriethoxysilane, 0.5-0.8 parts of isopropyltris(isostearoyl)titanate, 1-1.5 parts of polyvinyl butyral, 15-17 parts of ethyl acetate-isopropanol mixed solvent, 1-2 parts of propylene glycol methyl ether acetate, 0.9-1.3 parts of anti-aging agent, and 0.1-0.2 parts of storage stabilizer.

[0011] By adopting the above technical solution, the core of the adhesive is a terpolymer of methyl methacrylate-butyl acrylate-hydroxyethyl acrylate, which, in synergy with 3-(triethoxysilyl)propyl methacrylate, N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate, terpene phenolic resin, hydrogenated petroleum resin, and polyisobutylene resin, can be specifically adapted to substrates of different polarities. Simultaneously, the cohesive strength of the adhesive layer is enhanced by the combination of hexamethylene diisocyanate trimer, bisphenol A diglycidyl ether, and dibutyltin dilaurate to prevent debonding. The interfacial bonding with the substrate is further optimized by γ-aminopropyltriethoxysilane, isopropyltris(isostearoyl)titanate, and polyvinyl butyral. Anti-aging agents and storage stabilizers delay the performance degradation of the adhesive layer during use. Therefore, it can be adapted to various substrates without changing the formulation, thus improving the adhesive's compatibility with multiple substrates, bonding stability, and long-term reliability.

[0012] Preferably, the methyl methacrylate-butyl acrylate-hydroxyethyl acrylate terpolymer has a solid content of 48-52%, a number average molecular weight of 80,000-100,000, a dispersity of 1.8-2.2, and the weight ratio of methyl methacrylate, butyl acrylate, and hydroxyethyl acrylate is 35-40:50-55:5-10.

[0013] By adopting the above technical solution, the monomer ratio of the terpolymer balances rigidity, flexibility and crosslinking sites, and the molecular weight and solid content ensure that it dissolves uniformly in the solvent and can fully react with other components. Therefore, the effect of improving the overall toughness and crosslinking stability of the adhesive layer is achieved.

[0014] Preferably, the purity of 3-(triethoxysilyl)propyl methacrylate is ≥98%, the weight content of siloxane segments is 33-37%, the purity of the N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate composite monomer is ≥97%, and the molar ratio of N-(4-formylphenyl)acrylamide to hexamethylenediamine acrylate is 1:1.

[0015] By adopting the above technical solution, the use of high-purity monomers with specific content can avoid the influence of impurities on the compatibility with other components, and the fixed proportion of compound monomers can stably form dynamic covalent bonds. Therefore, the effect of ensuring the compatibility of the adhesive with non-polar substrates and the stability of its self-healing function is achieved.

[0016] Preferably, the softening point of the terpene phenolic resin is 125-135℃, the hydroxyl value is 180-200mgKOH / g, the softening point of the hydrogenated petroleum resin is 95-105℃, and the molecular weight of the polyisobutylene resin is 2000-3000.

[0017] By adopting the above technical solution, since the softening point and molecular weight of different tackifying resins are matched with each other, it can provide sufficient adhesion to substrates of different polarities, and avoid the embrittlement or insufficient adhesion of the adhesive layer caused by a single resin. Therefore, the effect of improving the adhesion of the adhesive to multiple substrates and the flexibility of the adhesive layer is achieved.

[0018] Preferably, the hexamethylene diisocyanate trimer has an NCO content of 20-22% and a solid content of 100%, the γ-aminopropyltriethoxysilane has a purity ≥98%, the isopropyltris(isostearoyl)titanate has a purity ≥95%, the titanium element has a weight content of 6.5-7.0%, the polyvinyl butyral has a butyraldehyde condensation degree of 70-75%, the anti-aging agent includes an ultraviolet absorber, a hindered amine light stabilizer, and a hindered phenol antioxidant, and the mass ratio is 2:1:1, respectively, and the storage stabilizer is triphenyl phosphite with a purity ≥98%.

[0019] By adopting the above technical solutions, the functional group content of the crosslinking agent ensures sufficient crosslinking reaction, the high-purity additives optimize the interface bonding with different substrates, the compounded anti-aging agents synergistically address multiple aging factors, and the storage stabilizers prevent component self-polymerization. Therefore, the effects of strengthening the crosslinking strength of the adhesive, substrate compatibility, and anti-aging ability are achieved.

[0020] Thirdly, this application provides a method for preparing an adhesive composition for decorative films, employing the following technical solution:

[0021] A method for preparing an adhesive composition for decorative films, applied to the above-mentioned adhesive composition for decorative films, includes the following steps:

[0022] Raw material pretreatment: By weight, ethyl acetate-isopropanol mixed solvent and propylene glycol methyl ether acetate are mixed and then used as base glue dissolving solvent and viscosity adjusting solvent in a weight ratio of 8:2. Then, methyl methacrylate-butyl acrylate-hydroxyethyl acrylate terpolymer is mixed and stirred with the base glue dissolving solvent to form a uniform and transparent base glue masterbatch.

[0023] Preparation of base adhesive: Add 3-(triethoxysilyl)propyl methacrylate to the base adhesive mother liquor by weight, stir and cool, then add N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate compound monomer and mix to obtain the base adhesive;

[0024] Resin mixing: According to the weight parts, the terpene phenolic resin is preheated and added to the base glue. After mixing and cooling, hydrogenated petroleum resin and polyisobutylene resin are added in sequence and stirred. Stirring is performed after each addition to obtain the tackifying base glue.

[0025] Additives: Add γ-aminopropyltriethoxysilane, isopropyltris(isostearoyl)titanate, and polyvinyl butyral to the tackifying adhesive in parts by weight. Stir after each addition, then add the anti-aging agent and mix to obtain a mixture.

[0026] Crosslinking control: Bisphenol A diglycidyl ether and dibutyltin dilaurate are added to the mixture according to the weight parts. After mixing, hexamethylene diisocyanate trimer is added dropwise and stirred. Then, a storage stabilizer is added and stirred to form a crosslinked product.

[0027] Post-processing: Add viscosity-adjusting solvent to the crosslinking material, stir to adjust the viscosity, filter under pressure using a nylon filter screen to obtain the filtrate, and let it stand to mature to obtain the adhesive composition for decorative film.

[0028] By adopting the above technical solutions, the raw material pretreatment ensures uniform dissolution of the base adhesive, the base adhesive preparation constructs a core system with adaptability, the resin mixing enhances the adhesive strength, the addition of additives improves compatibility and aging resistance, the crosslinking regulates the balance of strength and storage, and the post-treatment ensures construction compatibility. The synergy of each step makes the preparation process controllable, thus achieving the effect of a stable adhesive with uniform production performance.

[0029] Preferably, in the raw material pretreatment step, the mixing temperature is 30-35℃, the speed is 200-250 rpm, and the time is 60-90 min;

[0030] In the preparation of the base adhesive, the stirring and cooling process involves stirring at 35-40℃ and 300-350rpm for 40-50 minutes, followed by cooling to 30-32℃. The mixing rate is 300-350rpm and the time is 30-40 minutes.

[0031] By adopting the above technical solution, the base adhesive components can be fully dissolved without premature reaction through appropriate temperature and rate, and the appropriate time ensures thorough dissolution and mixing. Therefore, the effect of ensuring the uniformity of the base adhesive mother liquor and the functional stability of the base adhesive is achieved.

[0032] Preferably, in the resin mixing step, the preheating is performed at 50-55°C for 25-35 minutes, the mixing and cooling is performed at 40-45°C and 350-400 rpm for 50-60 minutes, and then cooled to 35-38°C, and the stirring is performed at 350-400 rpm for 30-35 minutes.

[0033] In the step of adding the additives, the stirring is carried out at 280-320 rpm for 15-25 minutes, and the mixing is carried out at 30-32℃ and 230-270 rpm for 45-55 minutes.

[0034] By adopting the above technical solution, the preheating makes the tackifying resin easier to dissolve, the appropriate temperature and rate prevent resin agglomeration or additive reaction, and the appropriate time ensures that each component is evenly dispersed. Therefore, the effect of ensuring that the tackifying system and additive functions can be fully utilized is achieved.

[0035] Preferably, in the crosslinking control step, the mixing is carried out at 32-35℃ and 250-300rpm for 30-35min, the dropping rate is 1-2 drops / second, the stirring time is 40-50min, and the stirring is carried out at 180-220rpm for 15-20min.

[0036] In the post-processing steps, the stirring is carried out at 180-220 rpm for 20-25 min, the viscosity is 1500-2000 cP at 25℃, the nylon filter screen has a mesh size of 100-120 mesh, the pressure of the pressure filtration is 0.2-0.3 MPa, and the standing curing is carried out at 25-30℃ in the dark for 20-24 h.

[0037] By adopting the above technical solutions, appropriate crosslinking parameters control the reaction process to avoid gelation, filtration removes impurities to ensure a smooth adhesive layer, and curing stabilizes the performance. Therefore, the effect of ensuring sufficient crosslinking of the adhesive, construction compatibility, and stable final performance is achieved.

[0038] In summary, this application has the following beneficial effects:

[0039] 1. Because this application uses a terpolymer of methyl methacrylate-butyl acrylate-hydroxyethyl acrylate as the core of the adhesive, and combines it with 3-(triethoxysilyl)propyl methacrylate, N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate composite monomers, terpene phenolic resin, hydrogenated petroleum resin, and polyisobutylene resin, it can be specifically adapted to substrates of different polarities. At the same time, the cohesive strength of the adhesive layer is improved by combining hexamethylene diisocyanate trimer, bisphenol A diglycidyl ether, and dibutyltin dilaurate to avoid debonding. The interfacial bonding with the substrate is further optimized by using γ-aminopropyltriethoxysilane, isopropyltris(isostearoyl)titanate, and polyvinyl butyral. The anti-aging agent and storage stabilizer delay the performance degradation of the adhesive layer during use. Therefore, it can be adapted to a variety of substrates without changing the formulation. Thus, the adhesive achieves the effect of improving the compatibility, bonding stability, and long-term reliability of the adhesive on multiple substrates.

[0040] 2. In this application, by introducing N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate composite monomers, the Schiff base type dynamic covalent bonds formed can achieve reversible breakage and recombination. When the decorative film develops microcracks due to thermal expansion and contraction or slight external force, the dynamic covalent bonds can repair the cracks through bond recombination, avoiding the delamination problem caused by crack propagation. This allows the decorative film to maintain an intact adhesive state after long-term use, extending the service life of the decorative film and reducing the secondary maintenance costs caused by delamination.

[0041] 3. In this application, methyl methacrylate provides rigidity, butyl acrylate provides flexibility, and hydroxyethyl acrylate provides crosslinking sites. Combined with the dual crosslinking system of bisphenol A diglycidyl ether and hexamethylene diisocyanate trimer, the epoxy crosslinking agent reacts with the carboxyl groups of the base adhesive, and the isocyanate crosslinking agent reacts with the hydroxyl groups of the base adhesive to form a non-interfering dual crosslinking network. This ensures the cohesive strength of the adhesive while retaining the flexibility of the adhesive layer. It can adapt to the thermal expansion and contraction of the substrate due to temperature changes during the use of the decorative film, avoids the adhesive layer from becoming brittle or delaminating, and ensures long-term stable bonding effect. Attached Figure Description

[0042] Figure 1 This is a flowchart of the method provided in this application. Detailed Implementation

[0043] The following is in conjunction with the appendix Figure 1 The present application will be further described in detail with reference to the embodiments.

[0044] Technical Concept: Decorative films are widely used in furniture surface decoration, building door and window cladding, and electronic device casing beautification. Their adhesion stability and long-term performance depend entirely on the adhesive performance. In related technologies, decorative film adhesives have poor compatibility with various substrates, often requiring a single formulation designed for a single substrate. For example, PVC requires an acrylic ester combined with terpene phenolic resin, PP requires modified natural rubber and corona pretreatment, and PET requires a siloxane-modified emulsion. Changing the substrate necessitates a simultaneous change of the adhesive, leading to frequent cleaning of production equipment and high changeover costs.

[0045] To address this issue, this invention employs a terpolymer of methyl methacrylate, butyl acrylate, and hydroxyethyl acrylate as the core adhesive, synergistically combined with 3-(triethoxysilyl)propyl methacrylate, N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate monomers, terpene phenolic resin, hydrogenated petroleum resin, and polyisobutylene resin. This allows for targeted adaptation to substrates of different polarities. Furthermore, the use of hexamethylene diisocyanate trimer, bisphenol A diglycidyl ether, and dibutyltin dilaurate enhances the cohesive strength of the adhesive layer to prevent debonding. The use of γ-aminopropyltriethoxysilane, isopropyltris(isostearoyl)titanate, and polyvinyl butyral further optimizes the interfacial bonding with the substrate. Anti-aging agents and storage stabilizers delay the performance degradation of the adhesive layer during use. Therefore, it can be adapted to various substrates without changing the formulation, thus improving the adhesive's compatibility with multiple substrates, bonding stability, and long-term reliability.

[0046] To better understand the above technical solutions, the technical solutions of the present invention will be clearly and completely described below in conjunction with embodiments.

[0047] Raw material source:

[0048] Unless otherwise specified, all experimental methods used below are conventional methods. All materials, reagents, methods, and instruments used, unless otherwise specified, are conventional materials, reagents, methods, and instruments in this field, which can be obtained commercially or prepared according to literature methods by those skilled in the art.

[0049] Preparation Example 1:

[0050] Preparation of methyl methacrylate-butyl acrylate-hydroxyethyl acrylate terpolymer:

[0051] Add 200 mL of ethyl acetate to a 500 mL three-necked flask, purge with nitrogen three times for 10 min each time to remove oxygen from the system;

[0052] Add 38g of methyl methacrylate, 52g of butyl acrylate, and 10g of hydroxyethyl acrylate in sequence, stir (300 rpm) until completely dissolved, and heat to 85°C;

[0053] Dissolve 0.5 g of azobisisobutyronitrile in 10 mL of ethyl acetate and slowly add it dropwise to a three-necked flask at a rate of 1 drop / second for 30 min. After the addition is complete, maintain the temperature at 85 °C and stir at 300 rpm for 4 h.

[0054] Cool to 30°C, stop nitrogen flow, pour the reaction solution into 1000 mL of n-hexane to precipitate, and filter to collect the white solid;

[0055] The solid was dried in a vacuum drying oven at 50°C and a vacuum degree of -0.09 MPa for 8 hours to obtain a white granular methyl methacrylate-butyl acrylate-hydroxyethyl acrylate terpolymer.

[0056] Preparation Example 2:

[0057] Preparation of N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate complex monomers:

[0058] Preparation of N-(4-formylphenyl)acrylamide:

[0059] Add 12.1 g of p-aminobenzaldehyde and 150 mL of dichloromethane to a 500 mL three-necked flask, stir at 200 rpm until dissolved, and cool to 0 °C in an ice bath.

[0060] Slowly add 10.1 g of triethylamine at a dropping rate of 1 drop / second, and after the addition is complete, maintain the temperature at 0°C and stir for 10 min.

[0061] Slowly add 8.5 g of acryloyl chloride at a dropping rate of 1 drop / second, keeping the system temperature ≤5℃. After the addition is complete, raise the temperature to 25℃ and continue stirring for 4 hours.

[0062] Add 50 mL of deionized water to the reaction solution and wash three times. Dry the organic phase with 20 g of anhydrous sodium sulfate for 2 h and filter.

[0063] The dichloromethane was removed by rotary evaporation at 40°C and a vacuum of -0.09 MPa. The remaining solid was recrystallized twice with ethanol to obtain white needle-like crystals of N-(4-formylphenyl)acrylamide.

[0064] Preparation of hexamethylenediamine acrylate:

[0065] Add 11.6 g of hexamethylenediamine and 200 mL of anhydrous ethanol to a 500 mL three-necked flask, stir at 200 rpm until dissolved, and cool to 0 °C in an ice bath.

[0066] Then, 14.4 g of acrylic acid was added dropwise at a rate of 1 drop / second. During the addition, the pH of the system was adjusted to 7-8 with triethylamine, and the pH fluctuation was controlled to be ≤0.2.

[0067] After the addition is complete, raise the temperature to 25°C and continue stirring for 12 hours;

[0068] The ethanol was removed by rotary evaporation at 50°C and a vacuum of -0.09 MPa. The remaining solid was recrystallized twice with ethyl acetate to obtain a white powder of hexamethylenediamine acrylate.

[0069] Preparation of compound monomers:

[0070] Take 19.9 g (0.1 mol) of N-(4-formylphenyl)acrylamide and 27.4 g (0.1 mol) of hexamethylenediamine acrylate prepared above, and add them to 100 mL of ethyl acetate;

[0071] Stir at 25℃ and 200 rpm for 30 minutes until the solid is completely dissolved, forming a homogeneous and transparent solution;

[0072] The ethyl acetate was removed by rotary evaporation at 40°C and a vacuum of -0.09 MPa to obtain a white, blocky N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate complex monomer, which was then sealed and stored in the dark.

[0073] The following is a further description with reference to the embodiments:

[0074] Example 1:

[0075] A decorative film includes a substrate layer, an adhesive layer, and a decorative wood grain layer disposed sequentially. The decorative wood grain layer is made of PVC, PP, or PET, and the material of the substrate layer matches the material of the decorative wood grain layer.

[0076] An adhesive composition for a decorative film, used in the aforementioned decorative film, comprises the following components in parts by weight: 58 parts of methyl methacrylate-butyl acrylate-hydroxyethyl acrylate terpolymer, 7 parts of 3-(triethoxysilyl)propyl methacrylate, 4.5 parts of N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate composite monomer, 14 parts of terpene phenolic resin, 11 parts of hydrogenated petroleum resin, 3 parts of polyisobutylene resin, 1.8 parts of hexamethylene diisocyanate trimer, 1.2 parts of bisphenol A diglycidyl ether, 0.2 parts of dibutyltin dilaurate, 1.7 parts of γ-aminopropyltriethoxysilane, 0.8 parts of isopropyltris(isostearoyl)titanate, 1.5 parts of polyvinyl butyral, 17 parts of ethyl acetate-isopropanol mixed solvent, 2 parts of propylene glycol methyl ether acetate, 1.3 parts of anti-aging agent, and 0.2 parts of storage stabilizer.

[0077] The solid content of the methyl methacrylate-butyl acrylate-hydroxyethyl acrylate terpolymer is 50%, the number average molecular weight is 90,000, the dispersity is 2, and the weight ratio of methyl methacrylate, butyl acrylate and hydroxyethyl acrylate is 37.5:52.5:7.5 respectively.

[0078] The purity of 3-(triethoxysilyl)propyl methacrylate is ≥98%, the weight content of siloxane segments is 35%, the purity of N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate composite monomer is ≥97%, and the molar ratio of N-(4-formylphenyl)acrylamide to hexamethylenediamine acrylate is 1:1.

[0079] The softening point of terpene phenolic resin is 130℃, the hydroxyl value is 190mgKOH / g, the softening point of hydrogenated petroleum resin is 100℃, and the molecular weight of polyisobutylene resin is 2500.

[0080] The hexamethylene diisocyanate trimer has an NCO content of 21% and a solid content of 100%. The purity of γ-aminopropyltriethoxysilane is ≥98%, the purity of isopropyltris(isostearoyl)titanate is ≥95%, the weight content of titanium is 6.75%, the degree of butyraldehyde condensation of polyvinyl butyral is 72.5%, and the anti-aging agents include ultraviolet absorbers, hindered amine light stabilizers and hindered phenolic antioxidants, with a mass ratio of 2:1:1, and the storage stabilizer is triphenyl phosphite with a purity of ≥98%.

[0081] A method for preparing an adhesive composition for decorative films, applied to the above-mentioned adhesive composition for decorative films, includes the following steps:

[0082] Raw material pretreatment: By weight, ethyl acetate-isopropanol mixed solvent and propylene glycol methyl ether acetate are mixed and then used as base glue dissolving solvent and viscosity adjusting solvent in a weight ratio of 8:2. Then, methyl methacrylate-butyl acrylate-hydroxyethyl acrylate terpolymer is mixed and stirred with the base glue dissolving solvent to form a uniform and transparent base glue masterbatch.

[0083] Preparation of base adhesive: Add 3-(triethoxysilyl)propyl methacrylate to the base adhesive mother liquor by weight, stir and cool, then add N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate compound monomer and mix to obtain the base adhesive;

[0084] Resin mixing: According to the weight parts, the terpene phenolic resin is preheated and added to the base glue. After mixing and cooling, hydrogenated petroleum resin and polyisobutylene resin are added in sequence and stirred. Stirring is performed after each addition to obtain the tackifying base glue.

[0085] Additives: Add γ-aminopropyltriethoxysilane, isopropyltris(isostearoyl)titanate, and polyvinyl butyral to the tackifying adhesive in parts by weight. Stir after each addition, then add the anti-aging agent and mix to obtain a mixture.

[0086] Crosslinking control: Bisphenol A diglycidyl ether and dibutyltin dilaurate are added to the mixture according to the weight parts. After mixing, hexamethylene diisocyanate trimer is added dropwise and stirred. Then, a storage stabilizer is added and stirred to form a crosslinked product.

[0087] Post-processing: Add viscosity-adjusting solvent to the crosslinking material, stir to adjust the viscosity, filter under pressure using a nylon filter screen to obtain the filtrate, and let it stand to mature to obtain the adhesive composition for decorative film.

[0088] In the raw material pretreatment step, the mixing temperature is 32.5℃, the speed is 225 rpm, and the time is 75 min;

[0089] In the preparation of the base adhesive, the stirring and cooling process involves stirring at 37°C and 325 rpm for 45 minutes, followed by cooling to 31°C. The mixing rate is 325 rpm, and the time is 35 minutes.

[0090] In the resin mixing process, the preheating is carried out at 53°C for 30 minutes, the mixing and cooling is carried out at 43°C and 375 rpm for 55 minutes, and the temperature is lowered to 36°C and stirred at 375 rpm for 33 minutes.

[0091] In the process of adding the additives, stirring is performed at 300 rpm for 20 minutes, and mixing is performed at 31°C and 250 rpm for 50 minutes.

[0092] In the crosslinking control step, the mixing was carried out at 34℃ and 275 rpm for 32.5 min, the dropping rate was 1 drop / second, the stirring time was 45 min, and the stirring was carried out at 200 rpm for 17.5 min.

[0093] In the post-processing steps, the stirring was carried out at 200 rpm for 22.5 min, the viscosity was 1750 cP at 25℃, the nylon filter screen had a mesh size of 110 mesh, the pressure for pressure filtration was 0.25 MPa, and the standing curing was carried out at 28℃ in the dark for 22 h.

[0094] Example 2:

[0095] The difference between this embodiment and Embodiment 1 above is that:

[0096] An adhesive composition for a decorative film, used in the aforementioned decorative film, comprises the following components in parts by weight: 52 parts of methyl methacrylate-butyl acrylate-hydroxyethyl acrylate terpolymer, 6 parts of 3-(triethoxysilyl)propyl methacrylate, 3.5 parts of N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate composite monomer, 12 parts of terpene phenolic resin, 9 parts of hydrogenated petroleum resin, 2 parts of polyisobutylene resin, 1.2 parts of hexamethylene diisocyanate trimer, 0.8 parts of bisphenol A diglycidyl ether, 0.1 parts of dibutyltin dilaurate, 1.3 parts of γ-aminopropyltriethoxysilane, 0.5 parts of isopropyltris(isostearoyl)titanate, 1 part of polyvinyl butyral, 15 parts of ethyl acetate-isopropanol mixed solvent, 1 part of propylene glycol methyl ether acetate, 0.9 parts of anti-aging agent, and 0.1 parts of storage stabilizer.

[0097] Example 3:

[0098] The difference between this embodiment and Embodiment 1 above is that:

[0099] An adhesive composition for a decorative film, used in the aforementioned decorative film, comprises the following components in parts by weight: 55 parts of methyl methacrylate-butyl acrylate-hydroxyethyl acrylate terpolymer, 6.5 parts of 3-(triethoxysilyl)propyl methacrylate, 4 parts of N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate composite monomer, 13 parts of terpene phenolic resin, 10 parts of hydrogenated petroleum resin, 2.5 parts of polyisobutylene resin, 1.5 parts of hexamethylene diisocyanate trimer, 1 part of bisphenol A diglycidyl ether, 0.15 parts of dibutyltin dilaurate, 1.5 parts of γ-aminopropyltriethoxysilane, 0.65 parts of isopropyltris(isostearoyl)titanate, 1.25 parts of polyvinyl butyral, 16 parts of ethyl acetate-isopropanol mixed solvent, 1.5 parts of propylene glycol methyl ether acetate, 1.1 parts of anti-aging agent, and 0.15 parts of storage stabilizer.

[0100] Example 4:

[0101] The difference between this embodiment and Embodiment 3 above is that:

[0102] The monomer weight ratio of the methyl methacrylate-butyl acrylate-hydroxyethyl acrylate terpolymer is 38:52:10, and the remaining components and preparation process are the same as in Example 3.

[0103] Example 5:

[0104] The difference between this embodiment and Embodiment 3 above is that:

[0105] The siloxane segment content of 3-(triethoxysilyl)propyl methacrylate is 37% by weight, and the remaining components and preparation process are completely consistent with those in Example 3.

[0106] Comparative Example 1:

[0107] The difference between this comparative example and Example 3 above is that:

[0108] The number average molecular weight of the polyisobutylene resin was 4000 (GPC method), and the remaining components and preparation process were the same as in Example 3.

[0109] Comparative Example 2:

[0110] The difference between this comparative example and Example 3 is that:

[0111] The N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate complex monomer is not used; the remaining components and preparation process are the same as in Example 3.

[0112] Comparative Example 3:

[0113] The difference between this comparative example and Example 3 is that:

[0114] The terpene phenolic resin and hydrogenated petroleum resin are not used; the remaining components and preparation process are the same as in Example 3.

[0115] Comparative Example 4:

[0116] The difference between this comparative example and Example 3 is that:

[0117] The product is free of γ-aminopropyltriethoxysilane, isopropyltris(isostearoyl)titanate, and polyvinyl butyral; the remaining components and preparation process are the same as in Example 3.

[0118] Comparative Example 5:

[0119] The difference between this comparative example and Example 3 is that:

[0120] The product is free of bisphenol A diglycidyl ether, and the remaining components and preparation process are the same as in Example 3.

[0121] Performance testing:

[0122] 90° peel strength (N / cm): Tested according to GB / T 2792-2014 "Determination of peel strength of adhesive tape", test speed 300mm / min, the adhesive strength of PVC, PP and PET substrates were tested respectively, and the average value was taken.

[0123] Self-healing efficiency (%): The ratio of the repaired strength to the initial peel strength after cutting a 50μm deep crack with a blade and heating at 60℃ for 2 hours is measured as 100%.

[0124] Peel strength retention rate after damp heat aging (%): The test was conducted according to GB / T 1740-2021 "Test Method for Damp Heat Resistance of Coating Film". The peel strength after aging was tested under damp heat conditions of 50℃ and 95%RH for 1000h, and the ratio of the peel strength to the initial value was multiplied by 100%.

[0125] Yellowing index ΔE after UV aging: Tested according to GB / T 2409-2021 "Test Method for Yellow Index of Plastics", UV conditions 340nm, 0.71W / m, placed for 1000h. 2

[0126] Peel strength retention rate after UV aging (%): Under the same UV aging conditions, the peel strength after aging is tested and the ratio of the initial value to 100%.

[0127] High temperature anti-degumming time (h): Placed in a constant temperature environment of 70℃, observe the time when degumming first occurs.

[0128] Table 1

[0129]

[0130] According to Table 1, and comparing Examples 1-5 with Comparative Example 1, the adhesive strength and high-temperature debonding time of Examples 1-5 are both higher than those of Comparative Example 1. This is because Examples 1-5 use polyisobutylene resin with a molecular weight within a defined range. This resin can be uniformly dispersed in the adhesive system, fully supplementing non-polar adhesive forces and balancing the toughness of the adhesive layer. In contrast, the polyisobutylene resin in Comparative Example 1 has a molecular weight exceeding the defined range, resulting in decreased dispersibility and an inability to effectively function, leading to insufficient adhesive strength and easy debonding at high temperatures. This demonstrates that controlling the molecular weight of polyisobutylene resin within the appropriate range can ensure both adhesive and debonding performance.

[0131] According to Table 1, and comparing Examples 1-5 with Comparative Example 2, the self-healing efficiency and performance retention rate after thermal cycling of Examples 1-5 are superior to those of Comparative Example 2. This is because the base adhesives of Examples 1-5 contain N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate composite monomers, which can form dynamic covalent bonds. Microcracks generated during thermal cycling can be repaired through bond recombination, maintaining the integrity of the adhesive network. In contrast, Comparative Example 2 lacks this composite monomer, exhibiting no dynamic repair effect; the continuous expansion of cracks leads to performance degradation. This indicates that the N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate composite monomer can improve the long-term stability and self-healing function of the adhesive.

[0132] According to Table 1, and comparing Examples 1-5 with Comparative Example 3, the adhesive strength and performance retention rate after damp heat aging of Examples 1-5 are higher than those of Comparative Example 3. Examples 1-5 utilize a compound tackifying system of terpene phenolic resin and hydrogenated petroleum resin. The terpene phenolic resin strengthens the adhesion of polar substrates, while the hydrogenated petroleum resin is suitable for non-polar substrates. Together, they achieve broad-spectrum adhesion across multiple substrates. In contrast, Comparative Example 3 lacks both of these resins, relying solely on polyisobutylene resin, which cannot accommodate different polar substrates, resulting in low adhesive strength and poor resistance to damp heat. This demonstrates that the compound tackifying resin system can achieve efficient adhesion across multiple substrates.

[0133] According to Table 1, and comparing Examples 1-5 with Comparative Example 4, it can be seen that the adhesion consistency of the multi-substrate mixture in Examples 1-5 and the performance retention rate after UV aging are both superior to those in Comparative Example 4. Specifically, Examples 1-5 added γ-aminopropyltriethoxysilane, isopropyltris(isostearoyl)titanate, and polyvinyl butyral, which optimized the interfacial bonding of PET, PP, and PVC substrates, respectively. In contrast, Comparative Example 4 lacked these additives, resulting in decreased wettability and interfacial bonding strength of the adhesive on different substrates, leading to poor adhesion consistency and reduced aging resistance. This demonstrates that these additives can improve the interfacial compatibility of the multi-substrate mixture.

[0134] According to Table 1, and comparing Examples 1-5 with Comparative Example 5, it can be seen that the high-temperature degumming time and performance retention rate after damp heat aging of Examples 1-5 are both higher than those of Comparative Example 5. This is because Examples 1-5 employ a dual crosslinking system of bisphenol A diglycidyl ether and hexamethylene diisocyanate trimer, forming a complete crosslinking network and improving cohesive strength and high-temperature resistance. In contrast, Comparative Example 5 lacks bisphenol A diglycidyl ether and relies only on a single crosslinking agent, resulting in insufficient network integrity and easy degumming at high temperatures. This demonstrates that the dual crosslinking system can ensure the high-temperature stability of the adhesive.

[0135] According to Table 1, a comparison between Examples 4-5 and Examples 1-3 shows that the adhesive strength and post-UV aging performance of Examples 4-5 are superior to those of Examples 1-3. Specifically, Example 4 optimized the monomer ratio of the methyl methacrylate-butyl acrylate-hydroxyethyl acrylate terpolymer, resulting in a better balance between rigidity, flexibility, and crosslinking sites; Example 5 adjusted the siloxane segment content of 3-(triethoxysilyl)propyl methacrylate, making it more suitable for non-polar substrates; both examples showed better synergy with other components, indicating that parameter optimization of each component can further improve the overall performance of the adhesive.

[0136] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. An adhesive composition for decorative films, characterized in that: The product comprises the following components in parts by weight: 52-58 parts of methyl methacrylate-butyl acrylate-hydroxyethyl acrylate terpolymer, 6-7 parts of 3-(triethoxysilyl)propyl methacrylate, 3.5-4.5 parts of N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate composite monomer, 12-14 parts of terpene phenolic resin, 9-11 parts of hydrogenated petroleum resin, 2-3 parts of polyisobutylene resin, and 1.2-1 parts of hexamethylene diisocyanate trimer. 8 parts, 0.8-1.2 parts of bisphenol A diglycidyl ether, 0.1-0.2 parts of dibutyltin dilaurate, 1.3-1.7 parts of γ-aminopropyltriethoxysilane, 0.5-0.8 parts of isopropyltris(isostearoyl)titanate, 1-1.5 parts of polyvinyl butyral, 15-17 parts of ethyl acetate-isopropanol mixed solvent, 1-2 parts of propylene glycol methyl ether acetate, 0.9-1.3 parts of anti-aging agent, and 0.1-0.2 parts of storage stabilizer.

2. A decorative film, comprising a substrate layer, an adhesive layer formed from the adhesive composition for decorative films according to claim 1, and a decorative wood grain layer disposed sequentially, characterized in that: The decorative wood grain layer is made of PVC, PP or PET, and the material of the substrate layer matches the material of the decorative wood grain layer.

3. The adhesive composition for decorative films according to claim 1, characterized in that: The terpolymer of methyl methacrylate-butyl acrylate-hydroxyethyl acrylate has a solid content of 48-52%, a number average molecular weight of 80,000-100,000, a dispersion of 1.8-2.2, and the weight ratio of methyl methacrylate, butyl acrylate, and hydroxyethyl acrylate is 35-40:50-55:5-10.

4. The adhesive composition for decorative film according to claim 1, characterized in that: The purity of the 3-(triethoxysilyl)propyl methacrylate is ≥98%, the weight content of the siloxane segment is 33-37%, the purity of the N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate composite monomer is ≥97%, and the molar ratio of N-(4-formylphenyl)acrylamide to hexamethylenediamine acrylate is 1:

1.

5. The adhesive composition for decorative film according to claim 1, characterized in that: The softening point of the terpene phenolic resin is 125-135℃, and the hydroxyl value is 180-200 mgKOH / g. The softening point of the hydrogenated petroleum resin is 95-105℃, and the molecular weight of the polyisobutylene resin is 2000-3000.

6. The adhesive composition for decorative film according to claim 1, characterized in that: The hexamethylene diisocyanate trimer has an NCO content of 20-22% and a solid content of 100%. The γ-aminopropyltriethoxysilane has a purity of ≥98%. The isopropyltris(isostearoyl)titanate has a purity of ≥95% and a titanium element weight content of 6.5-7.0%. The polyvinyl butyral has a butyraldehyde condensation degree of 70-75%. The anti-aging agent includes an ultraviolet absorber, a hindered amine light stabilizer, and a hindered phenol antioxidant, with a mass ratio of 2:1:

1. The storage stabilizer is triphenyl phosphite with a purity of ≥98%.

7. A method for preparing an adhesive composition for decorative films, characterized in that: The adhesive composition for decorative films according to any one of claims 1, 3-6 comprises the following steps: Raw material pretreatment: By weight, ethyl acetate-isopropanol mixed solvent and propylene glycol methyl ether acetate are mixed and then used as base glue dissolving solvent and viscosity adjusting solvent in a weight ratio of 8:

2. Then, methyl methacrylate-butyl acrylate-hydroxyethyl acrylate terpolymer is mixed and stirred with the base glue dissolving solvent to form a uniform and transparent base glue masterbatch. Preparation of base adhesive: Add 3-(triethoxysilyl)propyl methacrylate to the base adhesive mother liquor by weight, stir and cool, then add N-(4-formylphenyl)acrylamide-hexamethylenediamine acrylate compound monomer and mix to obtain the base adhesive; Resin mixing: According to the weight parts, the terpene phenolic resin is preheated and added to the base glue. After mixing and cooling, hydrogenated petroleum resin and polyisobutylene resin are added in sequence and stirred. Stirring is performed after each addition to obtain the tackifying base glue. Additives: Add γ-aminopropyltriethoxysilane, isopropyltris(isostearoyl)titanate, and polyvinyl butyral to the tackifying adhesive in parts by weight. Stir after each addition, then add the anti-aging agent and mix to obtain a mixture. Crosslinking control: Bisphenol A diglycidyl ether and dibutyltin dilaurate are added to the mixture according to the weight parts. After mixing, hexamethylene diisocyanate trimer is added dropwise and stirred. Then, a storage stabilizer is added and stirred to form a crosslinked product. Post-processing: Add viscosity-adjusting solvent to the crosslinking material, stir to adjust the viscosity, filter under pressure using a nylon filter screen to obtain the filtrate, and let it stand to mature to obtain the adhesive composition for decorative film.

8. The method for preparing an adhesive composition for decorative films according to claim 7, characterized in that: In the raw material pretreatment step, the mixing temperature is 30-35℃, the speed is 200-250rpm, and the time is 60-90min; In the preparation of the base adhesive, the stirring and cooling process involves stirring at 35-40℃ and 300-350rpm for 40-50 minutes, followed by cooling to 30-32℃. The mixing rate is 300-350rpm and the time is 30-40 minutes.

9. The method for preparing an adhesive composition for decorative films according to claim 7, characterized in that: In the resin mixing step, the preheating is to preheat at 50-55℃ for 25-35 minutes, the mixing and cooling is to stir at 40-45℃ and 350-400 rpm for 50-60 minutes, and then cool down to 35-38℃, and the stirring is to stir at 350-400 rpm for 30-35 minutes. In the step of adding the additives, the stirring is carried out at 280-320 rpm for 15-25 minutes, and the mixing is carried out at 30-32℃ and 230-270 rpm for 45-55 minutes.

10. The method for preparing an adhesive composition for decorative films according to claim 7, characterized in that: In the crosslinking control step, the mixing is carried out at 32-35℃ and 250-300rpm for 30-35min, the dropping rate is 1-2 drops / second, the stirring time is 40-50min, and the stirring is carried out at 180-220rpm for 15-20min. In the post-processing steps, the stirring is carried out at 180-220 rpm for 20-25 min, the viscosity is 1500-2000 cP at 25℃, the nylon filter screen has a mesh size of 100-120 mesh, the pressure of the pressure filtration is 0.2-0.3 MPa, and the standing curing is carried out at 25-30℃ in the dark for 20-24 h.

Images