Uv adhesion promoting optical adhesive film for glass bonding and method of making the same

Abstract

The application discloses a UV tackifying optical adhesive film for glass bonding and a preparation method thereof, the film is obtained by coating and curing of UV tackifying optical adhesive, the UV tackifying optical adhesive comprises the following raw material components in parts by weight: epoxy acrylic copolymer 30-50 parts; epoxy resin 40-60 parts; diluent 5-15 parts; photoinitiator 1-5 parts; auxiliary agent 0.5-4 parts. The film has high initial adhesion strength to the base material, and can ensure the positioning effect; after positioning, the film can be further crosslinked and hardened under certain UV irradiation, the adhesion ability of the film to the base material is greatly improved after hardening, and the modulus and strength of the film are also greatly improved, which not only ensures the adhesion effect, but also improves the long-term use resistance, and the film can be well applied to the bonding of planar electronic glass.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical adhesive materials, in particular to a UV tackifying optical adhesive film for glass bonding and a preparation method thereof. BACKGROUND

[0002] With the development of consumer electronics technology, consumers' demand for aesthetics and durability is increasing, which promotes the application and development of electronic glass in the field of electronic products such as mobile phones, computers, televisions, vehicles and wearable devices. Because it has many advantages such as good light transmittance, high strength, good toughness, scratch resistance, wear resistance and aesthetics.

[0003] Electronic glass generally adopts a multi-layer bonding and composite structure to meet the use requirements. Whether it is sodium calcium silicate glass or alkali alumino-silicate glass, the surface has high density and high surface energy, and is not easy to bond. By using a polymer coating, the bonding requirements can be met to some extent, but the disadvantages are also obvious. The coating area is uncontrollable, the edge difference is large, the coating is uneven, the edge accumulates material, and the shrinkage stress is large. Another is to use optical pressure-sensitive adhesive. Pressure-sensitive adhesive is extremely convenient to use, has initial adhesion that can be positioned, and only needs to apply a small pressure to achieve bonding, and does not need to be cured, so the bonding efficiency is very high. However, the modulus and strength of pressure-sensitive adhesive are low, and the adhesive layer is prone to slip after long-term use, and has poor solvent resistance.

[0004] To solve the above problems, the prior art usually starts from two directions. On the one hand, the polymer coating viscosity and coating process are adjusted to optimize the coating problem, but the effect is not ideal. On the other hand, the modulus of the optical pressure-sensitive adhesive is improved to improve the slip and other problems. By increasing the content of hard monomers and changing the crosslinking density, the performance of the product can be improved to some extent, but in this way the bonding capacity of the pressure-sensitive adhesive shows a downward trend, and the overall effect is still not ideal.

[0005] Therefore, it is necessary to improve the prior art to provide a more reliable solution. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a UV tackifying optical adhesive film for glass bonding and a preparation method thereof to solve the problems in the prior art.

[0007] To solve the above technical problems, the technical solution adopted by the present application is: a UV tackifying optical adhesive film for glass bonding, which is obtained by coating and curing a UV tackifying optical adhesive, the UV tackifying optical adhesive comprises the following raw material components by weight:

[0008]

[0009] Preferably, the epoxy resin is one or more of epoxy resin NPEL-128, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bis(3,4-epoxycyclohexylmethyl)adipate, triglycidyl isocyanurate, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate.

[0010] Preferably, the acrylic epoxy copolymer is obtained by polymerization of the following monomers by weight parts: butyl acrylate 20-40 parts, hydroxypropyl acrylate 10-20 parts, isobornyl acrylate 30-50 parts, epoxy monomer 15-25 parts.

[0011] The epoxy monomer is a mixture of one or more of glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, methylallyl glycidyl ether.

[0012] Preferably, the diluent is an epoxy diluent selected from one or more of butyl glycidyl ether, C12-14 glycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, p-tert-butylphenyl glycidyl ether, neopentyl glycol diglycidyl ether, cage polysilsesquioxane epoxy resin.

[0013] Preferably, the photoinitiator is one or more of sulfonium hexafluoroantimonate, iodonium hexafluoroantimonate, sulfonium hexafluorophosphate, iodonium hexafluorophosphate, benzoin methyl ether.

[0014] Preferably, the auxiliary agent includes one or more of defoaming agent, wetting agent, adhesion promoter, dispersant, leveling agent, coupling agent.

[0015] Preferably, the epoxy resin is a mixture of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate and epoxy resin NPEL-128;

[0016] The diluent is a mixture of 1,4-butanediol diglycidyl ether and cage polysilsesquioxane epoxy resin;

[0017] The photoinitiator is a mixture of sulfonium hexafluorophosphate and photoinitiator 184;

[0018] The auxiliary agent is a mixture of coupling agent A-187, leveling agent BYK333 and adhesion promoter BYK4510.

[0019] The application also provides a preparation method of the UV tackifying optical adhesive film for glass bonding as described above, comprising the following steps:

[0020] S1, preparing an acrylic epoxy copolymer;

[0021] S2, preparing UV adhesion optical glue: mixing epoxy acrylate copolymer, epoxy resin, diluent, photoinitiator, auxiliary agent to obtain UV adhesion optical glue;

[0022] S3, uniformly coating the UV adhesion optical glue prepared in step S2 on the first release film, drying, and then adhering the second release film to the glue surface to obtain the UV adhesion optical glue film for glass bonding.

[0023] Preferably, the step S1 specifically comprises:

[0024] S1-1, according to weight parts, the following monomers: butyl acrylate 20-40 parts, hydroxypropyl acrylate 10-20 parts, isobornyl acrylate 30-50 parts, epoxy monomer 15-25 parts, epoxy monomer is added to 100-200 parts of solvent, nitrogen is introduced, stirring and heating to 60-70℃, constant temperature reaction for 15-60min;

[0025] S1-2, adding 0.2-0.8% of the total mass of monomers initiator, reaction for 2-8h;

[0026] S1-3, heating to 72-80℃, adding 0.2-0.8% of the total mass of monomers initiator, reaction for 2-8h;

[0027] S1-4, after the reaction, the temperature is lowered to 25-35℃, and the epoxy acrylate copolymer is obtained.

[0028] Preferably, the preparation method of the UV adhesion optical glue film for glass bonding comprises the following steps:

[0029] S1, preparing an acrylic epoxy copolymer:

[0030] S1-1, according to weight parts, the following monomers: butyl acrylate 20-40 parts, hydroxypropyl acrylate 10-20 parts, isobornyl acrylate 30-50 parts, epoxy monomer 15-25 parts, epoxy monomer is added to 150 parts of solvent, nitrogen is introduced, stirring and heating to 65℃, constant temperature reaction for 30min;

[0031] The solvent is a mixture of ethyl acetate and toluene, and the weight ratio of ethyl acetate to toluene is 1:2 to 2:1;

[0032] S1-2, adding 0.3% of the total mass of monomers initiator AIBN, reaction for 4h;

[0033] S1-3, heating to 76℃, adding 0.5% of the total mass of monomers initiator AIBN, reaction for 4h;

[0034] S1-4, after the reaction, the temperature is lowered to 30℃, and the epoxy acrylate copolymer is obtained.

[0035] S2, preparing UV adhesion optical glue: mixing epoxy acrylate copolymer, epoxy resin, diluent, photoinitiator and auxiliary agent under light-proof condition and humidity less than 50% to obtain UV adhesion optical glue;

[0036] S3, uniformly coating the UV adhesion optical glue prepared in step S2 on the first release film, baking at 100-120 DEG C for 5-15 min, then pasting the second release film on the glue surface to obtain the UV adhesion optical glue film for glass bonding.

[0037] The beneficial effects of the present application are:

[0038] The present application provides a UV adhesion optical glue film for glass bonding and a preparation method thereof, the epoxy acrylate copolymer used in the preparation raw material of the glue film contains UV-curable epoxy monomer, the ether bond and hydroxyl group generated by epoxy ring opening have excellent adhesion to inorganic materials such as glass, and the formation of crosslinked network further ensures the bonding property and reliability in use; the introduction of UV-curable epoxy monomer ensures the film-forming property and provides the modulus and bonding performance of the product after curing;

[0039] In the present application, high-activity hexafluorophosphoric acid cationic initiator is used as photoinitiator, which ensures the curing property and provides excellent compatibility;

[0040] The glue film of the present application has high initial adhesion strength to the substrate, which can ensure the positioning effect; after positioning, the glue film can be further crosslinked and hardened under certain UV irradiation, the adhesion ability of the glue film to the substrate is greatly improved after hardening, and the modulus and strength of the glue film are also greatly improved, which ensures the adhesion effect and improves the long-term use resistance, and it can be well applied to the bonding of planar electronic glass. DETAILED DESCRIPTION

[0041] The present application will be further described in detail below with reference to the examples, so that those skilled in the art can implement it according to the description.

[0042] It should be understood that the terms such as "have", "contain" and "include" used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0043] The test methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples can be obtained commercially unless otherwise specified. The specific conditions are not specified in the following examples, and the conventional conditions or the conditions recommended by the manufacturer are used. The reagents or instruments used are not specified by the manufacturer, and are conventional products that can be obtained by commercial purchase.

[0044] The application provides a UV tackifying optical adhesive film for glass bonding, which is obtained by coating and curing of a UV tackifying optical adhesive, wherein the UV tackifying optical adhesive comprises the following raw material components by weight:

[0045]

[0046]

[0047] The acrylic epoxy copolymer is obtained by polymerization of the following monomers by weight: 20-40 parts of butyl acrylate, 10-20 parts of hydroxypropyl acrylate, 30-50 parts of isobornyl acrylate, and 15-25 parts of an epoxy monomer.

[0048] The epoxy monomer is a (meth)acrylate or a vinyl compound having a cationic reactive functional group. In a preferred embodiment, the epoxy monomer is a mixture of one or more of glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, and methylallyl glycidyl ether.

[0049] The epoxy resin can be an aromatic glycidyl ether, alicyclic glycidyl ether, alicyclic glycidyl ester, hydrogenated glycidyl ether, and a mixture thereof. In a preferred embodiment, the epoxy resin is one or more of epoxy resin NPEL-128, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bis(3,4-epoxycyclohexylmethyl)adipic acid, isocyanuric acid triglycidyl ester, and 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylformate.

[0050] The diluent is an epoxy diluent (a saturated or unsaturated cyclic and chain epoxy compound having at least one epoxy end). In a preferred embodiment, the diluent is one or more of butyl glycidyl ether, C12-14 glycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, p-tert-butyl phenyl glycidyl ether, neopentyl glycol diglycidyl ether, and cage-type polyhedral silsesquioxane epoxy resin.

[0051] The photoinitiator can be a photoinitiator of the diazonium salt, iron salt, iodonium salt, sulfonium salt, and the like. In a preferred embodiment, the photoinitiator is one or more of sulfonium hexafluoroantimonate, iodonium hexafluoroantimonate, sulfonium hexafluorophosphate, iodonium hexafluorophosphate, and cumene ferrocene hexafluorophosphate.

[0052] In a preferred embodiment, the adjuvant comprises one or more of a defoamer, a wetting agent, an adhesion promoter, a dispersant, a leveling agent, a coupling agent; for example, can include one or more of BYK-088, BYK A530, BYK 980, BYK DISPER 163, BYK 333, BYK 3550, BYK 4500, BYK 4510, KH560, KH 570, coupling agent A187, etc.

[0053] In a preferred embodiment, the epoxy resin is a mixture of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylmethyl carboxylate and epoxy resin NPEL-128;

[0054] The diluent is a mixture of 1,4-butanediol diglycidyl ether and cage polysilsesquioxane epoxy resin;

[0055] The photoinitiator is a mixture of hexafluorophosphonium sulfonium salt and photoinitiator 184;

[0056] The adjuvant is a mixture of coupling agent A-187, leveling agent BYK333 and adhesion promoter BYK4510.

[0057] The application also provides a preparation method of the above UV adhesion optical adhesive film for glass bonding, comprising the following steps:

[0058] S1, preparing an epoxy acrylic copolymer:

[0059] S1-1, according to parts by weight, the following monomers: butyl acrylate 20-40 parts, hydroxypropyl acrylate 10-20 parts, isobornyl acrylate 30-50 parts, epoxy monomer 15-25 parts, epoxy monomer is added to 150 parts of solvent, nitrogen is introduced, stirring is heated to 65℃, constant temperature reaction for 30min;

[0060] The solvent is a mixture of ethyl acetate and toluene, and the weight ratio of ethyl acetate to toluene is 1:2 to 2:1;

[0061] S1-2, adding 0.3% of initiator AIBN (azo diisobutyronitrile) based on the total mass of monomers, reacting for 4h;

[0062] S1-3, heating to 76℃, adding 0.5% of initiator AIBN based on the total mass of monomers, reacting for 4h;

[0063] S1-4, after the reaction is completed, the temperature is lowered to 30℃, and an epoxy acrylic copolymer is obtained.

[0064] S2, preparing a UV adhesion optical adhesive: mixing the epoxy acrylic copolymer, the epoxy resin, the diluent, the photoinitiator and the adjuvant under the conditions of light shielding and humidity less than 50% to obtain a UV adhesion optical adhesive.

[0065] S3, uniformly coating the UV adhesion optical adhesive prepared in step S2 on the first release film, baking at 100-120℃ for 5-15min, then laminating the second release film on the adhesive surface, to obtain the UV adhesion optical adhesive film for glass bonding.

[0066] The above is the general idea of the present application, and the following provides detailed examples and comparative examples based thereon to further illustrate the present application.

[0067] (1) In the UV adhesion optical adhesive film for glass bonding provided in the following examples and comparative examples, the raw materials for preparing the UV adhesion optical adhesive are all commercially available products except that the epoxy acrylate copolymer is self-made, and the specific sources are as follows:

[0068] The epoxy resin is a mixture of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexyl carboxylate (CELLOXIDE 2021P of DAICEL) and epoxy resin NPEL-128 (Nanya);

[0069] The diluent is a mixture of 1,4-butanediol diglycidyl ether (XinYuan XY622 of Anhui) and cage polysilsesquioxane epoxy resin (SY-EPSO 102L of Nisshinbo);

[0070] The photoinitiator is a mixture of hexafluorophosphoric acid sulfonium salt (PAG 202 of Qiangli, Changzhou) and photoinitiator 184 (IGM);

[0071] The auxiliary agent includes coupling agent A-187 (γ-glycidyl ether propyl trimethoxysilane, Momentive), leveling agent BYK333 (BYK), and adhesion promoter BYK4510 (Liancheng).

[0072] (2) The preparation method of the UV adhesion optical adhesive film for glass bonding in the following examples and comparative examples is the same, and the only difference is the formula components of the acrylic epoxy copolymer and the formula components of the UV adhesion optical adhesive, and the method comprises the following steps:

[0073] S1, preparing the acrylic epoxy copolymer:

[0074] S1-1, adding the following monomers: butyl acrylate, hydroxypropyl acrylate, isobornyl acrylate, epoxy monomer, epoxy monomer into a four-necked flask equipped with a stirrer, a condenser and a nitrogen tube, adding 150 parts by weight of solvent (a mixture of ethyl acetate: toluene in a weight ratio of 1:2-2:1), purging with nitrogen, stirring and heating to 65℃, and constant temperature reaction for 30min;

[0075] S1-2, 0.3% of initiator AIBN (azobisisobutyronitrile) based on the total mass of monomers was added, and the reaction was carried out for 4 h;

[0076] S1-3, the temperature was raised to 76℃, 0.5% of initiator AIBN based on the total mass of monomers was added, and the reaction was carried out for 4 h;

[0077] S1-4, after the reaction was completed, the temperature was lowered to 30℃, and an epoxy acrylate copolymer was obtained.

[0078] S2, UV adhesion optical glue was prepared: under the conditions of light shielding and humidity less than 50%, epoxy acrylate copolymer, epoxy resin, diluent, photoinitiator, and auxiliary were mixed to obtain UV adhesion optical glue;

[0079] S3, the UV adhesion optical glue prepared in step S2 was uniformly coated on the first release film, baked at 110℃ for 10 min, and then the second release film was laminated on the glue surface to obtain a UV adhesion optical glue film for glass bonding.

[0080] In the following examples and comparative examples, the formula components of the acrylic epoxy copolymer are shown in Table 1 below, and the formula components of the UV adhesion optical glue are shown in Table 2 below. The units in the following tables are parts by weight.

[0081] Table 1

[0082]

[0083]

[0084] Table 2

[0085]

[0086] The UV adhesion optical glue film for glass bonding prepared in Examples 1-6 and Comparative Examples 1-4 was cured and tested for the following properties. Comparative Example 2 could not form a film well and was not tested. The curing conditions were: ultraviolet irradiation was carried out under UV-LED 365 wavelength, and the cumulative energy was not less than 5000 mj.

[0087] The test method for storage modulus and Tg is as follows: the cured test piece was tested using a dynamic mechanical analyzer under the following conditions:

[0088] Test instrument: dynamic mechanical analyzer (DMA 1, METTLER TOLEDO); test piece size: 10*6*0.2mm; temperature range: -35~80℃; heating rate: 3℃ / min; deformation mode: tensile mode; test frequency: 1Hz.

[0089] The test items and results are shown in Table 3, wherein ● indicates that film formation is possible, O indicates that film formation is not possible, and Δ indicates that the test cannot be performed because film formation is not possible.

[0090] Table 3

[0091]

[0092] As can be seen from the test results in Table 3, the UV adhesion optical adhesive films prepared in Examples 1-5 have excellent performance in all aspects.

[0093] Comparative Example 1 does not add hydroxypropyl acrylate when synthesizing the epoxy acrylate copolymer, and the polarity is too low, and the product has poor adhesion performance.

[0094] Comparative Example 2 shrinks seriously during coating, and film formation fails, mainly because an excessive amount of hydroxypropyl acrylate is added to the synthesized epoxy acrylate copolymer, resulting in too high polarity.

[0095] In the epoxy acrylate copolymer synthesized in Comparative Example 3, the proportion of toluene in the mixed solvent is too high, and the product has poor UV pre-adhesion performance, mainly because of too low polymerization.

[0096] In Comparative Example 4, the proportion of toluene in the mixed solvent is too low when synthesizing the epoxy acrylate copolymer, although the product has good UV pre-adhesion performance, but the UV post-adhesion performance is greatly reduced, mainly because of too high polymerization.

[0097] Although the embodiments of the present application have been disclosed as above, it is not limited to the application listed in the specification and the embodiments, and can be fully applied to various fields suitable for the present application, and additional modifications can be easily made by those skilled in the art, and therefore the present application is not limited to specific details, but is within the general concept defined by the claims and the equivalent scope.

Claims

1. A UV-tackified optical adhesive film for glass bonding, characterized by, It is obtained by coating, curing after UV tackifying optical glue, the UV tackifying optical glue includes the following raw material components by weight parts: Acrylic epoxy copolymer 30-50 parts; Epoxy resin 40-60 parts; Diluent 5-15 parts; Photoinitiator 1-5 parts; Auxiliary 0.5-4 parts; The acrylic epoxy copolymer is obtained by polymerization of the following monomers by weight parts: butyl acrylate 20-40 parts, hydroxypropyl acrylate 10-20 parts, isobornyl acrylate 30-50 parts, epoxy monomer 15-25 parts; The epoxy monomer is a mixture of one or more of glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, and methyl allyl glycidyl ether; The epoxy resin is a mixture of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylmethyl carboxylate and epoxy resin NPEL-128; The diluent is a mixture of 1,4-butanediol diglycidyl ether and cage polysilsesquioxane epoxy resin; The photoinitiator is a mixture of hexafluorophosphonium sulfonium salt and photoinitiator 184; The preparation method of the acrylic epoxy copolymer is: S1-1, by weight parts, the following monomers: butyl acrylate 20-40 parts, hydroxypropyl acrylate 10-20 parts, isobornyl acrylate 30-50 parts, epoxy monomer 15-25 parts are added into 100-200 parts of solvent, nitrogen is introduced, stirring is heated to 60-70℃, constant temperature reaction is carried out for 15-60 min;Wherein, the solvent is a mixture of ethyl acetate and toluene, and the weight ratio of ethyl acetate to toluene is 1:2~2:1; S1-2, 0.2-0.8% of the total mass of monomers is added to the initiator, and the reaction is carried out for 2-8 h; S1-3, heating to 72-80℃, 0.2-0.8% of the total mass of monomers is added to the initiator, and the reaction is carried out for 2-8 h; S1-4, after the reaction is finished, the temperature is reduced to 25-35℃, and the acrylic epoxy copolymer is obtained.

2. The UV tackifying optical adhesive film for glass bonding according to claim 1, wherein The auxiliary includes one or more of defoaming agent, wetting agent, adhesion promoter, dispersant, leveling agent, coupling agent.

3. The UV tackifying optical adhesive film for glass bonding according to claim 1, wherein The auxiliary is a mixture of coupling agent A-187, leveling agent BYK333 and adhesion promoter BYK4510.

4. A method of producing a UV-tackified optical adhesive film for glass bonding according to any one of claims 1 to 3, characterized by, Including the following steps: S1, preparation of acrylic epoxy copolymer; S2, preparation of UV tackifying optical glue: acrylic epoxy copolymer, epoxy resin, diluent, photoinitiator, auxiliary are mixed to obtain UV tackifying optical glue; S3, the UV tackifying optical glue prepared in step S2 is uniformly coated on the first layer of release film, and the second layer of release film is adhered to the glue surface after drying, to obtain the UV tackifying optical glue film for glass bonding.

5. The method for preparing the UV-adhesive optical adhesive film for glass bonding according to claim 4, characterized in that, Including the following steps: S1, preparation of acrylic epoxy copolymer: S1-1, by weight parts, the following monomers: butyl acrylate 20-40 parts, hydroxypropyl acrylate 10-20 parts, isobornyl acrylate 30-50 parts, epoxy monomer 15-25 parts are added into 150 parts of solvent, nitrogen is introduced, stirring is heated to 65℃, constant temperature reaction is carried out for 30 min; The solvent is a mixture of ethyl acetate and toluene, and the weight ratio of ethyl acetate to toluene is 1:2-2:1; S1-2, adding 0.3% of initiator AIBN based on the total mass of monomers, and reacting for 4 hours; S1-3, heating to 76℃, adding 0.5% of initiator AIBN based on the total mass of monomers, and reacting for 4 hours; S1-4, after the reaction is completed, cooling to 30℃, to obtain the acrylic epoxy copolymer; S2, preparing UV tackifying optical glue: mixing the acrylic epoxy copolymer, epoxy resin, diluent, photoinitiator and auxiliary agent under the conditions of light shielding and humidity less than 50%, to obtain the UV tackifying optical glue; S3, uniformly coating the UV tackifying optical glue prepared in step S2 on the first release film, baking at 100-120℃ for 5-15 minutes, and then adhering the second release film to the glue surface, to obtain the UV tackifying optical glue film for glass bonding.

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