UV curing type high-strength pressure-sensitive structural adhesive tape and preparation method thereof

Abstract

The invention discloses a UV curing type high-strength pressure-sensitive structural adhesive tape and a preparation method thereof. The pressure-sensitive adhesive raw material of the UV curing type high-strength pressure-sensitive structural adhesive tape comprises the following components in parts by weight: acrylic acid-2-ethylhexyl ester; butyl acrylate; methyl methacrylate; hydroxyethyl acrylate; acrylic acid; 2, 2 '-azobisisobutyronitrile; a crosslinking agent, wherein the crosslinking agent is selected from glycidyl methacrylate, bisphenol A diglycidyl ether or N-methoxy acrylamide; a catalyst; a diluting monomer, wherein the diluting monomer is selected from pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate or dipentaerythritol hexanoic acid acrylate; 0.5 to 5.0 parts of a photoinitiator; and a solvent. The UV curing type high-strength pressure-sensitive structural adhesive tape disclosed by the invention has good strength and weather resistance, and can still keep relatively good strength at an extreme temperature.

Description

Technical Field

[0001] The invention relates to the field of adhesives, and in particular to a UV-curable high-strength pressure-sensitive structural adhesive tape and a preparation method thereof. Background Art

[0002] Acrylic pressure-sensitive adhesive is a type of pressure-sensitive copolymer prepared from acrylate monomers by solution polymerization, emulsion polymerization or other methods.

[0003] As the demand for acrylic pressure-sensitive adhesives continues to expand, the adhesive market is gradually expanding, and different application scenarios have also put forward higher requirements for its performance. For example, when used as adhesive labels for different products, due to different product usage conditions and storage conditions, the adhesive is required to adhere firmly to the substrate under a series of different temperature and humidity conditions; this requires adjusting the adhesive composition and synthesis conditions to increase the ability to resist changes in external conditions as much as possible.

[0004] Therefore, how to provide a UV-curable high-strength pressure-sensitive structural tape with good weather resistance is a technical problem that needs to be solved urgently in this field. Summary of the invention

[0005] To achieve the above object, the present invention provides a UV-curable high-strength pressure-sensitive structural adhesive tape and a preparation method thereof.

[0006] The present invention provides a method for preparing a UV-curable high-strength pressure-sensitive structural adhesive tape, which comprises the following steps:

[0007] The pressure-sensitive adhesive is coated on the substrate, baked at 100-180°C, and a release film is attached to obtain a UV-curable high-strength pressure-sensitive structural tape;

[0008] The preparation method of the pressure-sensitive adhesive comprises the following steps:

[0009] The raw materials of the pressure-sensitive adhesive include the following components by weight:

[0010] 2-Ethylhexyl acrylate: 40-50 parts;

[0011] Butyl acrylate: 20-30 parts;

[0012] Methyl methacrylate: 10 parts;

[0013] Hydroxyethyl acrylate: 10 parts;

[0014] Acrylic acid: 10 parts;

[0015] Azobisisobutyronitrile: 0.05-1.0 parts;

[0016] Crosslinking agent: 4 - 6 parts, and the crosslinking agent is selected from glycidyl methacrylate, bisphenol A diglycidyl ether or N - methoxyacrylamide;

[0017] Catalyst: 0.05 - 1.0 part;

[0018] Diluting monomer: 10 - 20 parts, and the diluting monomer is selected from: pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate or dipentaerythritol hexaacrylate;

[0019] Photoinitiator: 0.5 - 5.0 parts;

[0020] Solvent;

[0021] The preparation method of the pressure - sensitive adhesive comprises the following steps:

[0022] (1) Mix the 2 - ethylhexyl acrylate, butyl acrylate, methyl methacrylate, 2 - hydroxyethyl acrylate, acrylic acid and part of the solvent evenly by stirring under the atmosphere of nitrogen protection to obtain mixture 1. Mix azobisisobutyronitrile and the remaining part of the solvent to dissolve and obtain a solution, and slowly drop the solution into mixture 1, and continue the reaction to obtain an acrylate copolymer;

[0023] (2) Mix the acrylate copolymer, the crosslinking agent, the catalyst, the active diluent and the photoinitiator to obtain mixture 2;

[0024] (3) Subject mixture 2 to photocuring and drying to obtain the pressure - sensitive adhesive.

[0025] In a preferred embodiment of the present invention, the number of parts of 2 - ethylhexyl acrylate is 40 parts, 45 parts or 50 parts.

[0026] In a preferred embodiment of the present invention, the number of parts of butyl acrylate is 20 parts, 25 parts or 30 parts.

[0027] In a preferred embodiment of the present invention, the amount of azobisisobutyronitrile is 0.5 part.

[0028] In a preferred embodiment of the present invention, the number of parts of the crosslinking agent is 4 parts, 5 parts or 6 parts.

[0029] In a preferred embodiment of the present invention, the number of parts of the diluting monomer is 10 parts, 15 parts or 20 parts.

[0030] In a preferred embodiment of the present invention, the number of parts of the photoinitiator is 1.0 - 3.0 parts, such as 2.0 parts.

[0031] In a preferred embodiment of the present invention, the types of the photoinitiator are photoinitiator 6976, photoinitiator 1173, photoinitiator 184 or photoinitiator 907.

[0032] In a preferred embodiment of the present invention, the type of the solvent is ethyl acetate.

[0033] In a preferred embodiment of the present invention, the dosage of the solvent is 100 parts.

[0034] In a preferred embodiment of the present invention, the dropping time of the solution is 3 h.

[0035] In a preferred embodiment of the present invention, the reaction temperature in Step 1 is 70 - 80 °C, for example 75 °C.

[0036] In a preferred embodiment of the present invention, the reaction time in Step 1 is 2 - 4 h, for example 3 h.

[0037] In a preferred embodiment of the present invention, the photocuring time in Step 3 is 400 s.

[0038] In a preferred embodiment of the present invention, the photocuring conditions in Step 3 are light source wavelength 365 nm and curing energy 5000 mJ.

[0039] In a preferred embodiment of the present invention, the drying conditions are drying at 100 °C for 30 min.

[0040] The present invention also provides a UV-curable high-strength pressure-sensitive structural tape, which is prepared by the above method.

[0041] The reagents and raw materials used in the present invention are all commercially available.

[0042] The positive and progressive effects of the present invention are as follows:

[0043] The UV-curable high-strength pressure-sensitive structural tape prepared from the acrylate copolymer made of 2-EHA, BA, MMA, HEA, AA and a specific crosslinking agent (GMA, BADGE or NMOAM), and a diluent monomer (PETA, TMPETA or DPHA) in the present invention has good strength and weather resistance, and can still maintain good strength at extreme temperatures. Detailed Embodiments

[0044] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0045] In the following examples and comparative examples, the full names and English abbreviations of each raw material are as follows:

[0046] 2-Ethylhexyl acrylate, abbreviated as 2-EHA;

[0047] Butyl acrylate, abbreviated as BA;

[0048] Methyl methacrylate, MMA;

[0049] 2-Hydroxyethyl acrylate, abbreviated as HEA;

[0050] Acrylic acid, abbreviated as AA;

[0051] 2,2'-Azobis(2-methylpropionitrile): AIBN;

[0052] Glycidyl methacrylate: GMA;

[0053] Bisphenol A diglycidyl ether: BADGE;

[0054] N-Methoxyacrylamide: NMOAM;

[0055] Isocyanatoethyl methacrylate: MOI;

[0056] Isocyanatoethyl acrylate: AOI;

[0057] Dibutyltin dilaurate: DBTDL

[0058] Pentaerythritol triacrylate: PETA;

[0059] Ethoxylated trimethylolpropane triacrylate: TMPETA;

[0060] Dipentaerythritol hexaacrylate: DPHA;

[0061] Trimethylolpropane triacrylate: TMPTA;

[0062] Tripropylene glycol diacrylate: TPGDA.

[0063] Examples 1-3, Comparative Examples 1-4

[0064] For the UV-curable high-strength pressure-sensitive structural tapes in Examples 1-3 and Comparative Examples 1-4, calculated by weight parts, the formula and process conditions are shown in Table 1 below.

[0065] Table 1

[0066] Formulation Example 1 Example 2 Example 3 2-EHA 40 parts 45 parts 50 parts BA 30 parts 25 parts 20 parts MMA 10 parts 10 parts 10 parts HEA 10 parts 10 parts 10 parts AA 10 parts 10 parts 10 parts Type of initiator AIBN AIBN AIBN Parts of initiator 0.5 part 0.5 part 0.5 part Type of solvent Ethyl acetate Ethyl acetate Ethyl acetate Parts of solvent 100 parts 100 parts 100 parts Type of crosslinking agent GMA BADGE NMOAM Parts of crosslinking agent 4 parts 5 parts 6 parts DBTDL 0.5 part 0.5 part 0.5 part Type of photoinitiator Photoinitiator 6976 Photoinitiator 1173 Photoinitiator 184 Parts of photoinitiator 2.0 parts 2.0 parts 2.0 parts Type of diluent monomer PETA TMPETA DPHA Parts of diluent monomer 10 parts 15 parts 20 parts

[0067] The UV-curable high-strength pressure-sensitive structural tapes in Examples 1-3 and Comparative Examples 1-4 include a substrate layer, a pressure-sensitive adhesive layer, and a release film layer that are sequentially laminated. The preparation method is as follows: The pressure-sensitive adhesive is coated on the substrate, baked at 100-180 °C, and the release film is laminated to obtain the UV-curable high-strength pressure-sensitive structural tape.

[0068] According to the formula shown in Table 1, the preparation methods of the pressure-sensitive adhesive layers in Examples 1-3 and Comparative Examples 1-4 are as follows:

[0069] Step 1: 2-EHA, BA, MMA, HEA, AA, and 40 parts of ethyl acetate are stirred and mixed evenly under a nitrogen-protected atmosphere to obtain Mixture 1. The temperature is slowly raised to 75 °C. AIBN and 60 parts of ethyl acetate are mixed and dissolved to obtain a solution, which is slowly added dropwise (completed within 3 h) to Mixture 1 at 75 °C, and the reaction continues for 3 h to obtain an acrylate copolymer.

[0070] Step 2: The acrylate copolymer in Step 1 is heated in a water bath, and the temperature is raised to 50 °C. Oxygen is slowly introduced using an oxygen generator for 30 min to quench the possible residual initiator in the system. Keeping the temperature in the reaction flask at 50 °C constant, the crosslinking agent, DBTDL, active diluent, and photoinitiator are mixed to obtain Mixture 2.

[0071] Step 3: Mixture 2 is coated on a polyethylene terephthalate (PET) film using a 20-μm wire bar, placed in a light curing machine for curing for 400 s (fully cured by irradiation with a light source wavelength of 365 nm and a curing energy of 5000 mJ), and dried in an oven at 100 °C for 30 min to obtain the UV-curable high-strength pressure-sensitive structural tape.

[0072] Comparative Example 1

[0073] Except that the type of crosslinking agent is replaced with MOI, other conditions are the same as in Example 1.

[0074] Comparative Example 2

[0075] Except that the type of crosslinking agent is replaced with AOI, other conditions are the same as in Example 1.

[0076] Comparative Example 3

[0077] Except that the type of diluent monomer is replaced with TMPTA, other conditions are the same as in Example 1.

[0078] Comparative Example 4

[0079] Except that the type of diluent monomer is replaced with TPGDA, other conditions are the same as in Example 1.

[0080] Effect Example 1

[0081] The shear strength, pull-out strength, and weather resistance of the UV-curable high-strength pressure-sensitive structural tapes in Test Examples 1-3 and Comparative Examples 1-4.

[0082] The shear strength of the tape after UV curing was detected according to GB / T 33332-2016 "Test Method for Dynamic Shear Strength of Adhesive Tapes".

[0083] Pull-out strength: A design scheme with one layer of pressure-sensitive adhesive and T-shaped aluminum blocks on both sides was adopted to measure the pull-out strength. The pressure-sensitive tape was adhered to the 3003 T-shaped aluminum block, UV cured, a 0.2 mm thick pressure-sensitive adhesive was coated on the back of the substrate, and a T-shaped aluminum block of the same size was adhered to the pressure-sensitive adhesive. After standing at room temperature for 7 days, the fixture was symmetrically fixed on the tensile machine gripper, the tensile machine was started, and the specimen was stretched at a speed of 5 mm / min, and the maximum value at the time of failure was recorded as the failure load of the specimen.

[0084] Weather resistance test:

[0085] (1) Double 85 experiment: The UV-cured specimen was placed in an environment of 85°C high temperature and 85% relative humidity for 1000 h, and the shear strength was detected again.

[0086] (2) Thermal shock experiment: The UV-cured specimen was alternately exposed to temperatures of -40°C and 80°C for 168 cycle switches, and the shear strength was detected.

[0087] The specific results are shown in Table 2.

[0088] Table 2

[0089]

[0090] As can be seen from Table 2:

[0091] (1) The acrylate copolymer prepared from 2-EHA, BA, MMA, HEA, and AA, and the UV-curable high-strength pressure-sensitive structural tape prepared with a specific cross-linking agent (GMA, BADGE, or NMOAM) and a diluent monomer (PETA, TMPETA, or DPHA) in Examples 1-4 have good strength and weather resistance.

[0092] (2) The UV-curable high-strength pressure-sensitive structural tapes prepared with MOI and AOI as cross-linking agents in Comparative Example 1 and Comparative Example 2, and TMPTA and TPGDA as diluent monomers in Comparative Example 3 and Comparative Example 4 have poor strength and weather resistance.

Claims

1. A method for preparing a UV-curable high-strength pressure-sensitive structural tape, characterized in that: It includes the following steps: The pressure-sensitive adhesive is coated on the substrate, baked at 100-180°C, and a release film is attached to obtain a UV-curable high-strength pressure-sensitive structural tape; The preparation method of the pressure-sensitive adhesive comprises the following steps: The raw materials of the pressure-sensitive adhesive include the following components by weight: 2-Ethylhexyl acrylate: 40-50 parts; Butyl acrylate: 20-30 parts; Methyl methacrylate: 10 parts; Hydroxyethyl acrylate: 10 parts; Acrylic acid: 10 parts; Azobisisobutyronitrile: 0.05-1.0 parts; Cross-linking agent: 4-6 parts, the cross-linking agent is selected from glycidyl methacrylate, bisphenol A diglycidyl ether or N-methoxyacrylamide; Catalyst: 0.05-1.0 part; Dilution monomer: 10-20 parts, the dilution monomer is selected from: pentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate or dipentaerythritol hexaacrylate; Photoinitiator: 0.5-5.0 parts; Solvents; The method for preparing the pressure-sensitive adhesive comprises the following steps: (1) stirring and mixing the 2-ethylhexyl acrylate, the butyl acrylate, the methyl methacrylate, the hydroxyethyl acrylate, the acrylic acid and part of the solvent under a nitrogen atmosphere to obtain a mixture 1, mixing and dissolving the azobisisobutyronitrile and the remaining part of the solvent to obtain a solution, slowly dropping the solution into the mixture 1, and continuing the reaction to obtain an acrylate copolymer; (2) mixing the acrylic ester copolymer, the crosslinking agent, the catalyst, the diluent monomer, and the photoinitiator to obtain a mixture 2; (3) The mixture 2 is photocured and dried to obtain the pressure-sensitive adhesive.

2. The method for preparing the UV-curable high-strength pressure-sensitive structural tape according to claim 1, characterized in that: The amount of 2-ethylhexyl acrylate is 40 parts, 45 parts or 50 parts.

3. The method for preparing the UV-curable high-strength pressure-sensitive structural adhesive tape according to claim 1, characterized in that: The amount of butyl acrylate is 20 parts, 25 parts or 30 parts.

4. The method for preparing the UV-curable high-strength pressure-sensitive structural tape according to claim 1, characterized in that: The amount of azobisisobutyronitrile is 0.5 parts.

5. The method for preparing the UV-curable high-strength pressure-sensitive structural tape according to claim 1, characterized in that: The amount of the cross-linking agent is 4 parts, 5 parts or 6 parts.

6. The method for preparing the UV-curable high-strength pressure-sensitive structural tape according to claim 1, characterized in that: The diluent monomer is present in an amount of 10 parts, 15 parts or 20 parts.

7. The method for preparing a UV-curable high-strength pressure-sensitive structural tape according to claim 1, characterized in that: The photoinitiator is present in an amount of 1.0-3.0 parts; And / or, the type of the photoinitiator is photoinitiator 6976, photoinitiator 1173, photoinitiator 184 or photoinitiator 907.

8. The method for preparing the UV-curable high-strength pressure-sensitive structural tape according to claim 1, characterized in that: The solution was added dropwise for 3 h.

9. The method for preparing a UV-curable high-strength pressure-sensitive structural adhesive tape according to any one of claims 1 to 8, characterized in that: The reaction temperature in step 1 is 70-80°C; And / or, the reaction time in step 1 is 2-4h.

10. A UV-curable high-strength pressure-sensitive structural adhesive tape, which is prepared by the preparation method of the UV-curable high-strength pressure-sensitive structural adhesive tape according to any one of claims 1 to 9.

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