Tackified adhesive film

Abstract

The present invention relates to the technical field of tackified adhesive films and specifically to a tackified adhesive film. The tackified adhesive film comprises a substrate layer and a UV-tackified adhesive layer applied onto the substrate layer. The UV-tackified adhesive layer is prepared by using a modified polyester resin, which is obtained by the graft polymerization of a hydroxyl-terminated polyester resin, butyl methacrylate, and isocyanatoethyl methacrylate, as a main resin and mixing the main resin with a tackifying resin, a photo-curing agent and the like. The UV-tackified adhesive layer has relatively high cohesive strength and relatively good adhesion to a PET substrate. Before a UV-induced tackification reaction, an initial peel force is not significantly increased with the extension of standing time, so that an adhesive tape can be easily removed without causing damage and contamination such as residual adhesive to an adherend . After the UV-induced tackification reaction, the modified polyester resin can improve the bonding strength between the adhesive tape and the adherend.

Description

An adhesive film TECHNICAL FIELD

[0001] The present application relates to the technical field of adhesive film, in particular to an adhesive film. BACKGROUND

[0002] With the development of display technology, the adhesive tape needs to have strong adhesion and reworkability. For example, in the OLED module segment, a high-adhesion supporting film is attached to fix the OLED screen PI, but due to the excessive adhesion, poor attachment will cause a certain yield loss. Currently, an adhesive tape is used, such as thermal adhesion, UV adhesion, etc. The characteristics of such adhesive tapes are low initial adhesion, good reworkability, strong adhesion after adhesion, and strong adhesion. By coating the adhesion glue on the surface of the substrate, the solid-gas interface of the original substrate is replaced, and the adhesion adhesive tape is prepared through drying, pressing and curing.

[0003] However, the volume shrinkage caused by the UV crosslinking reaction of the current UV adhesion adhesive film is too large, which causes the warping and deformation of the product during the aging process, and the crosslinking density is too large, which affects the attachment of the product and the stability of the later processing process parameters. SUMMARY

[0004] In view of the above-mentioned shortcomings of the prior art, the present application provides an adhesive film which can effectively solve the above-mentioned problems existing in the prior art.

[0005] TECHNICAL SCHEME

[0006] In order to achieve the above-mentioned purposes, the present application is realized by the following technical scheme:

[0007] The present application provides an adhesive film, which comprises a substrate layer and a UV adhesion adhesive layer coated on the substrate layer. The UV adhesion adhesive layer is prepared by using a modified polyester resin obtained by grafting polymerization of a hydroxyl-terminated polyester resin, isocyanatoethyl methacrylate and (meth) acrylate monomer as a main body resin, and mixing with adhesion resin and photocuring agent.

[0008] Further, a catalyst and a free radical polymerization initiator are also added in the preparation process of the modified polyester resin, wherein the catalyst is dibutyltin dilaurate.

[0009] Further, the specific preparation steps of the modified polyester resin are as follows:

[0010] (1) The hydroxyl-terminated polyester resin, isocyanatoethyl methacrylate (MOI), dibutyltin dilaurate, organic solvent are mixed into the reactor, heated to 50-70℃, and reacted at this temperature for 4-6h;

[0011] (2) The temperature is raised to 70-90°C, and then a mixture of (meth)acrylate monomers and a radical polymerization initiator is slowly added to the reactor, and a graft polymerization reaction is performed for 3-5 hours to obtain a modified polyester resin solution;

[0012] The above reactions are all performed under nitrogen protection.

[0013] Further, the modified polyester resin is prepared according to the following steps:

[0014] (1) 60-90 parts by weight of a hydroxyl-terminated polyester resin, 0.5-3 parts by weight of isocyanatoethyl methacrylate (MOI), 0.01-0.10 parts by weight of dibutyltin dilaurate, and 100 parts by weight of an organic solvent are mixed in a reactor, and the temperature is raised to 60°C, and a reaction is performed at this temperature for 5 hours;

[0015] (2) The temperature is raised to 80°C, and then a mixture of 7-39.5 parts by weight of (meth)acrylate monomers and 0.1-2 parts by weight of a radical polymerization initiator is slowly added to the reactor, and a graft polymerization reaction is performed for 4 hours to obtain a modified polyester resin solution;

[0016] The above reactions are all performed under nitrogen protection.

[0017] In step (1), the organic solvent is one or more of ethyl acetate, toluene, acetone, butanone, and isopropyl alcohol, which are mixed in any ratio;

[0018] The (meth)acrylate monomers include at least one or more of (meth)acrylic acid alkyl esters, (meth)acrylic acid esters containing an aromatic ring, (meth)acrylic acid hydroxyalkyl esters, (meth)acrylic acid glycidyl esters, (meth)acrylic acid alkoxyalkyl esters, (meth)acrylic acid allyl alkyl esters, and multifunctional (meth)acrylic acid esters.

[0019] Preferably, the (meth)acrylate monomers include at least one or more of (meth)acrylic acid methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid butyl ester, (meth)acrylic acid 2-ethylhexyl ester, (meth)acrylic acid octyl ester, (meth)acrylic acid dodecyl ester, (meth)acrylic acid stearyl ester, and (meth)acrylic acid behenyl ester.

[0020] Preferably, the (meth)acrylate monomers include at least one or more of (meth)acrylic acid ethyl ester, (meth)acrylic acid butyl ester, and (meth)acrylic acid 2-ethylhexyl ester, and most preferably, the (meth)acrylate monomers are (meth)acrylic acid butyl ester.

[0021] In the present specification, (meth)acrylate refers to acrylate and / or methacrylate.

[0022] The radical polymerization initiator is selected from at least one or both of benzoyl peroxide and azobisisobutyronitrile.

[0023] Preferably, the modified polyester resin is prepared by the following steps:

[0024] (1) 75 parts of a hydroxyl-terminated polyester resin, 2.18 parts of isocyanatoethyl methacrylate (MOI), 0.075 parts of dibutyltin dilaurate, and 100 parts of an organic solvent are mixed in a reactor, heated to 60°C, and reacted at this temperature for 5 h;

[0025] (2) The temperature is raised to 80°C, and then a mixture of 20 parts of a (meth)acrylate monomer and 1 part of a radical polymerization initiator is slowly added to the reactor, and grafted polymerization is carried out for 4 h to obtain a modified polyester resin solution;

[0026] The above reactions are all carried out under nitrogen protection.

[0027] Further, the tackifying resin is hydrogenated rosin glycerin ester.

[0028] Further, the photocuring agent is one or more of 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, trimethylolpropane triacrylate, and trimethylolpropane trimethacrylate.

[0029] Preferably, the photocuring agent is 1,6-hexanediol diacrylate (HDDA) and trimethylolpropane triacrylate, and the weight ratio of 1,6-hexanediol diacrylate (HDDA) to trimethylolpropane triacrylate is 3:1.

[0030] Further, the crosslinking agent is a polyisocyanate curing agent or a carboxyl crosslinking agent that can react with a hydroxyl group or a carboxyl group; the polyisocyanate curing agent is a compound containing two or more isocyanate groups in one molecule, and is one of an aromatic polyisocyanate or an aliphatic polyisocyanate; the carboxyl crosslinking agent is one or more of a multifunctional aziridine (trimethylolpropane-tris[3-(2-methylaziridinyl)propionate], SC-100) and a tetrafunctional epoxy resin (N,N,N',N'-tetraglycidyl-m-diaminodiphenylmethane, GA-240).

[0031] Further, the initiator is one or more of radical type initiators such as 1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyldiphenyl phosphine oxide, 2,4,6-trimethylbenzoyl ethyl phenyl phosphonate, phenyl bis(2,4,6-trimethylbenzoyl) phosphine oxide, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl) butanone and 2-dimethylamino-2-benzyl-1-(4-piperidinophenyl)-1-butanone.

[0032] The auxiliary agent includes a stabilizer, which is a phenolic compound or a quinone compound, and the stabilizer is one or a mixture of several of 4-methoxyphenol, 4-methoxynaphthol, tertiary butyl hydroquinone, dibutyl hydroxytoluene, benzoquinone and 1,4-naphthoquinone.

[0033] Further, the UV tackifying adhesive layer contains 30-50 parts of modified polyester resin, 10-30 parts of photocuring agent, 5-10 parts of tackifying resin, 0.2-3 parts of crosslinking agent, 0.5-2 parts of initiator and 0.01-0.1 parts of auxiliary agent by weight.

[0034] Further, the UV tackifying adhesive layer contains 35-45 parts of modified polyester resin, 15-25 parts of photocuring agent, 6.5-9 parts of tackifying resin, 0.5-1.5 parts of crosslinking agent, 0.5-1.5 parts of initiator and 0.01-0.1 parts of auxiliary agent by weight.

[0035] A method for preparing a tackifying adhesive film, comprising the following steps:

[0036] (1) First, the modified polyester resin and photocuring agent are added to a solvent and stirred to obtain a mixed solution, and then the tackifying resin, crosslinking agent, initiator and auxiliary agent are added to the mixed solution and stirred uniformly to obtain a tackifying adhesive;

[0037] (2) The tackifying adhesive obtained in step (1) is coated on the surface of the substrate layer, heated at 50-130°C for 3-5 min for drying and curing, and then a release film is attached, and the obtained product is aged at 40-50°C for 48-72 h to obtain a UV tackifying adhesive film;

[0038] In step (1), the solvent is one or a mixture of several of ethyl acetate, toluene, acetone, butanone and isopropyl alcohol in any proportion.

[0039] The thickness of the release film layer is 25-100 μm, and the release film layer is a silicone release film or a non-silicone release film; preferably, the release film layer is PET.

[0040] The thickness of the UV tackifying adhesive layer is 5 μm-100 μm;

[0041] The substrate layer is one of PET, PO / PP / PE, PI or PEN, and the thickness of the substrate layer is 5-300 μm. Preferably, the substrate layer is PET.

[0042] The substrate layer is PET (polyethylene terephthalate), PO / PP / PE (polyolefin film), PI (polyimide film) or PEN (polyethylene naphthalate), and the thickness of the substrate layer is 5-300 μm. Advantages

[0043] Compared with the known prior art, the technical solution provided by the present application has the following advantages:

[0044] (1) The tackifying adhesive film prepared by using the modified polyester resin obtained by graft polymerization of hydroxyl-terminated polyester resin, butyl methacrylate and isocyanatoethyl methacrylate as the main resin, and mixing with tackifying resin and photocuring agent, etc., has high cohesive strength and good PET substrate adhesion. Before UV tackifying reaction, the initial peeling force does not increase significantly with the extension of the standing time, so that the adhesive tape can be removed conveniently without damaging the pasted object and causing pollution such as residual glue.

[0045] (2) The adhesive film of the present application has high initial adhesion strength to the substrate, which can ensure the positioning effect. After positioning, the adhesive film can be further crosslinked and hardened under certain UV irradiation, and after hardening, the adhesion of the adhesive film to the substrate is greatly improved, and the modulus and strength of the adhesive film are also greatly improved, which not only ensures the adhesion effect, but also improves the long-term use resistance, and can be well applied to the bonding of planar electronic glass.

[0046] (3) In the present application, the polyester resin and the PET as the substrate are both polyester materials, therefore, the UV tackifying adhesive layer prepared has high cohesive strength and good PET substrate adhesion. The UV adhesive layer obtained by modifying the polyester resin does not have a significant increase in the initial peeling force with the extension of the standing time before UV tackifying reaction, so that the adhesive tape can be removed conveniently without damaging the pasted object and causing pollution such as residual glue. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0048] Figure 1 is a schematic diagram of the UV adhesion film structure of the present application.

[0049] The reference signs in the figure respectively represent: 1 - substrate layer, 2 - UV adhesion glue layer, 3 - release film layer. DETAILED DESCRIPTION

[0050] To make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the protection scope of the present application.

[0051] The present application will be further described below with reference to the embodiments.

[0052] The sources and models of raw materials in the synthesis experiments, embodiments and comparative examples are as follows:

[0053] Hydrogenated rosin glyceride, Shenzhen Yoshida Chemical Co., Ltd.;

[0054] 1,6-hexanediol diacrylate (HDDA), Changxing Chemical Material Co., Ltd.;

[0055] Isocyanatoethyl methacrylate (MOI), Japan Showa Denko;

[0056] Hydroxyl-terminated polyester resin, Japan Toyo Spinning Co., Ltd., model GK680 (hydroxyl value: 21 mg / g KOH);

[0057] Carboxyl-terminated polyester resin, Anhui Shenjian SJ6B;

[0058] Rosin phenolic resin, Arakawa Chemical Industry Co., Ltd., model T-803L;

[0059] (I) Synthesis of modified polyester resin

[0060] Synthesis Experiment 1:

[0061] Under nitrogen protection, 75 parts of hydroxyl-terminated polyester resin, 100 parts of organic solvent, 2.18 parts of isocyanatoethyl methacrylate, 0.075 parts of dibutyltin dilaurate catalyst were added into the reactor in parts by weight and mixed, and the temperature was raised to 60°C for 5h; then the temperature was raised to 80°C, and then a mixture of 20 parts of (meth)acrylate monomer and 1 part of free radical polymerization initiator was slowly added into the reaction container, and the graft polymerization reaction was carried out for 4h to obtain the modified polyester resin GX1.

[0062] Among them, the (meth)acrylate monomer is butyl methacrylate;

[0063] Radical polymerization initiator: benzoyl peroxide and azobisisobutyronitrile, and the weight ratio is 2:1;

[0064] The organic solvent is ethyl acetate.

[0065] Synthesis Experiment 2:

[0066] Compared with Synthesis Experiment 1, the only difference is that the hydroxyl-terminated polyester resin is replaced by carboxyl-terminated polyester resin.

[0067] The modified polyester resin GX2 is prepared by Synthesis Experiment 2.

[0068] Synthesis Experiment 3:

[0069] Compared with Synthesis Experiment 1, the only difference is that no isocyanatoethyl methacrylate is added.

[0070] The modified polyester resin GX3 is prepared by Synthesis Experiment 3.

[0071] (B) Preparation of Adhesion Film

[0072] Example 1:

[0073] An adhesion film, comprising the following preparation steps:

[0074] (1) First, 40 parts of modified polyester resin, 20 parts of photocuring agent are added to 150 parts of ethyl acetate and stirred to obtain a mixed solution, then 7.5 parts of tackifying resin, 0.75 parts of crosslinking agent, 1 part of initiator and 0.05 parts of auxiliary agent are added to the mixed solution, and after stirring for 1 h, an adhesion glue is obtained.

[0075] (2) The adhesion glue obtained in step (1) is coated on the surface of a 75 μm thick transparent PET substrate film layer, dried and cured at 90℃ for 4 min and laminated with a 50 μm thick transparent PET release film, and then cured at 45℃ for 60 h to obtain a UV adhesion film.

[0076] The thickness of the adhesion glue layer is 18 μm.

[0077] The modified polyester resin is GX1;

[0078] The photocuring agent is 1,6-hexanediol diacrylate (HDDA) and trimethylolpropane triacrylate, and the weight ratio of 1,6-hexanediol diacrylate (HDDA) and trimethylolpropane triacrylate is 3:1.

[0079] The tackifying resin is hydrogenated rosin glyceride;

[0080] The crosslinking agent is a multifunctional aziridine (trimethylolpropane-tris[3-(2-methylaziridinyl)propionate], SC-100);

[0081] The initiator is 2,4,6-trimethylbenzoyldiphenyl phosphine oxide;

[0082] The auxiliary agent is tert-butyl hydroquinone.

[0083] Example 2:

[0084] A tackified adhesive film, comprising the following preparation steps:

[0085] (1) 35 parts of modified polyester resin, 25 parts of photocuring agent are first added into 150 parts of ethyl acetate to stir and mix to obtain a mixed solution, and then 6.5 parts of tackifying resin, 1.5 parts of crosslinking agent, 0.5 parts of initiator and 0.05 parts of auxiliary agent are added into the mixed solution, and after stirring for 1 h, a tackifying adhesive is obtained;

[0086] (2) The tackifying adhesive obtained in step (1) is coated on the surface of a 75 μm thick transparent PET base film layer, dried and cured at 90℃ for 4 min and laminated with a 50 μm thick transparent PET release film, and then aged at 45℃ for 60 h to obtain a UV tackified adhesive film;

[0087] The thickness of the tackifying adhesive layer is 18 μm.

[0088] The modified polyester resin is GX1;

[0089] The photocuring agent is 1,6-hexanediol diacrylate (HDDA) and trimethylolpropane triacrylate, and the weight ratio of 1,6-hexanediol diacrylate (HDDA) and trimethylolpropane triacrylate is 3:1;

[0090] The tackifying resin is hydrogenated rosin glyceride;

[0091] The crosslinking agent is a multifunctional aziridine (trimethylolpropane-tris[3-(2-methylaziridinyl)propionate], SC-100);

[0092] The initiator is 2,4,6-trimethylbenzoyldiphenyl phosphine oxide;

[0093] The auxiliary agent is tert-butyl hydroquinone.

[0094] Example 3:

[0095] A tackified adhesive film, comprising the following preparation steps:

[0096] (1) first 45 parts of modified polyester resin, 15 parts of light curing agent into 150 parts of ethyl acetate stirring mixed to get mixed liquid, then 9 parts of tackifying resin, 0.5 parts of crosslinking agent, 0.9 parts of initiator and 0.03 parts of auxiliary are added into the mixed liquid, stirring for 1h, then the tackifying glue is obtained;

[0097] (2) the tackifying glue obtained in step (1) is coated on the surface of 75 μm thick transparent PET substrate film layer, dried and cured at 90℃ for 4 min and laminated with 50 μm thick transparent PET release film, and then aged at 45℃ for 60h to obtain UV tackifying glue film;

[0098] The thickness of the tackifying glue layer is 18 μm.

[0099] The modified polyester resin is GX1.

[0100] The light curing agent is 1,6-hexanediol diacrylate (HDDA) and trimethylolpropane triacrylate, and the weight ratio of 1,6-hexanediol diacrylate (HDDA) and trimethylolpropane triacrylate is 3:1.

[0101] The tackifying resin is hydrogenated rosin glyceride.

[0102] The crosslinking agent is multifunctional aziridine (trimethylolpropane-tris[3-(2-methylaziridinyl) propionate], SC-100).

[0103] The initiator is 2,4,6-trimethylbenzoyl diphenyl phosphate.

[0104] The auxiliary is tert-butyl hydroquinone.

[0105] Comparative Example 1:

[0106] The difference from Example 1 is only that the modified polyester resin is GX2.

[0107] Comparative Example 2:

[0108] The difference from Example 1 is only that the modified polyester resin is GX3.

[0109] Comparative Example 3:

[0110] The difference from Example 1 is only that no tackifying resin is added.

[0111] Comparative Example 4:

[0112] The difference from Example 1 is only that the tackifying resin is rosin phenolic resin (model: T-803L, manufacturer: Arakawa Chemical Industry Co., Ltd.).

[0113] Comparative Example 5:

[0114] The difference from Example 1 is that the photocuring agent is 1,6-hexanediol diacrylate (HDDA).

[0115] Comparative Example 6:

[0116] The difference from Example 1 is that the photocuring agent is trimethylolpropane triacrylate.

[0117] (III) Performance Test

[0118] The UV adhesion film prepared in the above examples and comparative examples was tested for peel strength before and after UV, reliability aging performance under different conditions, and aging shrinkage rate, and the test method was as follows.

[0119] (1) Initial 180° peel strength test: each example sample was cut into 25 mm wide and 250 mm long, and the release film was removed and attached to a 75 μm*50 mm*150 mm PI film. The end of each strip was clamped on the stretching clamp of the tensile testing machine, and 180° peeling was performed at a speed of 300 mm / min. Five sets of data were tested and averaged.

[0120] (2) UV adhesion 180° peel strength test: each example sample was cut into 25 mm wide and 250 mm long, and the release film was removed and attached to a 75 μm*50 mm*150 mm PI film. A 365 nm LED light source was used to irradiate the sample, and the light energy was 4000 mj / cm 2 (200 mw / cm 2 intensity for 20 seconds), the end of each strip was clamped on the stretching clamp of the tensile testing machine, and 180° peeling was performed at a speed of 300 mm / min. Five sets of data were tested and averaged.

[0121] (3) Substrate adhesion test: according to JIS K 5600 standard, 10x10 squares were drawn on the adhesive layer of the UV adhesion tape sample prepared above at an interval of 1 mm, and transparent tape (3M, Scotch Tape) was used to cover and peel off quickly at an angle of 90°. The number of squares that were not peeled off was recorded, and the results were judged according to the following standard:

[0122] O: 100 / 100

[0123] Δ: 99 / 100-80 / 100

[0124] X: 0 / 100-79 / 100

[0125] (4) Dual 85 aging test: each sample of the examples is cut into 50mm wide, 150mm long, and the release film is removed and attached to a 75pm*100mm*200mm PI film, a 365nm LED light source is used to irradiate the sample, the light energy is 4000mj / cm 2 (200mw / cm 2 light intensity for 20 seconds), the sample is placed in a constant temperature and humidity chamber at 85°C & 85% relative humidity for aging for 240 hours, whether there are bubbles, delamination, fracture and other defects between the sample and the PI film are observed, if there are no above defects, it is "qualified", if there are any defects, it is "unqualified".

[0126] (5) 60°C / 90% aging test: each sample of the examples is cut into 50mm wide, 150mm long, and the release film is removed and attached to a 75pm*100mm*200mm PI film, a 365nm LED light source is used to irradiate the sample, the light energy is 4000mj / cm 2 (200mw / cm 2 light intensity for 20 seconds), the sample is placed in a constant temperature and humidity chamber at 60°C & 90% relative humidity for aging for 240 hours, whether there are bubbles, delamination, fracture and other defects between the sample and the PI film are observed, if there are no above defects, it is "qualified", if there are any defects, it is "unqualified".

[0127] (6) -40°C aging test: each sample of the examples is cut into 50mm wide, 150mm long, and the release film is removed and attached to a 75pm*100mm*200mm PI film, a 365nm LED light source is used to irradiate the sample, the light energy is 4000mj / cm 2 (200mw / cm 2 light intensity for 20 seconds), the sample is placed in a constant temperature and humidity chamber at -40°C relative humidity for aging for 240 hours, whether there are bubbles, delamination, fracture and other defects between the sample and the PI film are observed, if there are no above defects, it is "qualified", if there are any defects, it is "unqualified".

[0128] (7) Cold and hot impact aging test: each sample of the examples is cut into 50mm wide, 150mm long, and the release film is removed and attached to a 75pm*100mm*200mm PI film, a 365nm LED light source is used to irradiate the sample, the light energy is 4000mj / cm 2 (200mw / cm 2 light intensity for 20 seconds), the sample is placed in a -40°C~85°C cycle / 30min cold and hot impact chamber for aging for 100 cycles, whether there are bubbles, delamination, fracture and other defects between the sample and the PI film are observed, if there are no above defects, it is "qualified", if there are any defects, it is "unqualified".

[0129] (8) Aging shrinkage test: cut each sample into A4 sample size, remove the release film and adhere on a 250mm*330mm glass plate, use a 365nm LED light source to irradiate the sample, the light energy is 4000mj / cm 2 (200mw / cm 2 irradiate for 20 seconds, use a high-precision two-dimensional microscope to test the four side lengths, place the sample in a constant temperature and humidity chamber at 85℃ and 85% relative humidity for 240 hours, take it out and cool it to room temperature, then use the above microscope to test the four side lengths again, use the aging shrinkage formula:

[0130] The specific test results are shown in the following table:

[0131] As can be seen from the examples and comparative examples, the modified polyester resin obtained by grafting polymerization of hydroxyl-terminated polyester resin, butyl methacrylate and isocyanatoethyl methacrylate as the main resin, and mixed with tackifying resin and photocuring agent, etc. to prepare a tackifying adhesive film has high cohesive strength and good PET substrate adhesion. Before UV tackifying reaction, the initial peeling force does not increase significantly with the extension of storage time, so the adhesive tape can be removed conveniently without damaging the adherend and causing pollution such as residue.

[0132] The adhesive film of the present application has high initial adhesion strength to the substrate, which can ensure the positioning effect. After positioning, the adhesive film can be further crosslinked and hardened under certain UV irradiation, and the adhesion of the adhesive film to the substrate is greatly improved after hardening, which not only ensures the adhesion effect, but also improves the long-term use resistance, and it can be well applied to the bonding of planar electronic glass.

[0133] In the present application, the polyester resin and the PET as the substrate are both polyester materials, therefore, the UV tackifying adhesive layer prepared has high cohesive strength and good PET substrate adhesion. The UV adhesive layer obtained by modifying the polyester resin does not have a significant increase in initial peeling force with the extension of storage time before UV tackifying reaction, so the adhesive tape can be removed conveniently without damaging the adherend and causing pollution such as residue.

[0134] The above examples are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced by equivalent features; and these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present application.

Claims

1. An adhesive film, characterized by, It comprises a base material layer and a UV tackifying glue layer coated on the base material layer, wherein the UV tackifying glue layer is prepared by using a modified polyester resin obtained by graft polymerization of a hydroxyl-terminated polyester resin, isocyanatoethyl methacrylate and (meth) acrylate monomer as a main body resin, and mixing with a tackifying resin and a photocuring agent.

2. The tackified adhesive film according to claim 1, wherein The catalyst is dibutyltin dilaurate.

3. The tackified adhesive film according to claim 2, wherein The modified polyester resin is prepared by the following steps: (1) the hydroxyl-terminated polyester resin, isocyanatoethyl methacrylate, dibutyltin dilaurate and organic solvent are mixed in a reactor, heated to 50-70℃, and reacted at the temperature for 4-6h; (2) the temperature is raised to 70-90℃, and then the mixture of (meth) acrylate monomer and free radical polymerization initiator is slowly added into the reactor, and graft polymerization is carried out for 3-5h to obtain the modified polyester resin; The above reactions are all carried out under nitrogen protection.

4. The tackified adhesive film according to claim 2, wherein The modified polyester resin is prepared by the following steps: (1) the hydroxyl-terminated polyester resin, isocyanatoethyl methacrylate, dibutyltin dilaurate and organic solvent are mixed in a reactor, heated to 50-70℃, and reacted at the temperature for 4-6h; (2) the temperature is raised to 70-90℃, and then the mixture of (meth) acrylate monomer and free radical polymerization initiator is slowly added into the reactor, and graft polymerization is carried out for 3-5h to obtain the modified polyester resin; The above reactions are all carried out under nitrogen protection. In step (1), the organic solvent is ethyl acetate, toluene, acetone, butanone and isopropyl alcohol, which are mixed in any ratio.

5. The tackified adhesive film according to claim 1, wherein The (meth) acrylate monomer includes at least one of (meth) acrylate alkyl ester, (meth) acrylate containing aromatic ring, (meth) acrylate hydroxyl alkyl ester, (meth) acrylate glycidyl ester, (meth) acrylate alkoxy alkyl ester, (meth) acrylate allyl alkyl ester and multifunctional (meth) acrylate; and the free radical polymerization initiator is at least one of benzoyl peroxide and azobisisobutyronitrile.

6. The tackified adhesive film according to claim 1, wherein The tackifying resin is hydrogenated rosin glyceride.

7. The tackified adhesive film according to claim 6, wherein The photocuring agent is one or more of 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, trimethylolpropane triacrylate and trimethylolpropane trimethacrylate.

8. The tackified adhesive film according to claim 7, wherein It further comprises a crosslinking agent, an initiator and an auxiliary agent, wherein the crosslinking agent is a polyisocyanate curing agent or a carboxyl crosslinking agent; The polyisocyanate curing agent is one of aromatic polyisocyanate or aliphatic polyisocyanate; and the carboxyl crosslinking agent is one or more of multifunctional aziridine and tetrafunctional epoxy resin. The initiator is one or more of 1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyl diphenyl phosphine oxide, 2,4,6-trimethylbenzoyl phenyl ethyl phosphonate, phenyl bis(2,4,6-trimethylbenzoyl) phosphine oxide, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl) butanone and 2-dimethylamino-2-benzyl-1-(4-piperidinophenyl)-1-butanone radical type initiators; The auxiliary agent includes a stabilizer which is one or a mixture of several of 4-methoxyphenol, 4-methoxynaphthol, tertiary butyl hydroquinone, dibutyl hydroxytoluene, benzoquinone and 1,4-naphthoquinone.

9. The tackified adhesive film according to claim 8, wherein The UV tackifying adhesive layer contains 30-50 parts of modified polyester resin, 10-30 parts of photocuring agent, 5-10 parts of tackifying resin, 0.2-3 parts of crosslinking agent, 0.5-2 parts of initiator and 0.01-0.1 parts of auxiliary agent by weight.

10. A method of preparing a tack film as claimed in claim 9, characterized in that: It includes the following steps: (1) first, the modified polyester resin, photocuring agent is added to the solvent and stirred to obtain a mixed solution, and then the tackifying resin, crosslinking agent, initiator and auxiliary agent are added to the mixed solution, and after stirring uniformly, a tackifying glue is obtained; (2) the tackifying glue obtained in step (1) is coated on the surface of the substrate layer, heated at 50-130℃ for 3-5min to dry and cure and attached to the release film, cured at 40-50℃ for 48-72h to obtain a UV tackifying adhesive film; In step (1), the solvent is one or a mixture of several of ethyl acetate, toluene, acetone, butanone and isopropyl alcohol in any proportion.

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