Photocuring adhesive, preparation method thereof, display screen and electronic equipment

Abstract

The invention provides a photocuring adhesive, a preparation method thereof, a display screen and electronic equipment. The photocuring adhesive comprises 50 to 100 parts of prepolymer monomer, 1 to 10 parts of active monomer containing photosensitive group, 1 to 3 parts of cross-linking agent and 0.1 to 1 part of initiator. The photocuring adhesive is irradiated by ultraviolet light in a first wavelength range, and photodimerization reaction is carried out between photosensitive groups to generate a dimer; the dimer of the photocuring adhesive is subjected to dimerization reaction under the irradiation of ultraviolet light in a second wavelength range. According to the photocuring adhesive provided by the invention, the photodimerization reaction can be carried out between the photosensitive groups under the irradiation of the ultraviolet light in the first wavelength range to generate a dimer, so that the adhesive force of the adhesive is increased to a certain extent, and the photocuring adhesive is convenient to use; and the photocuring adhesive can also enable the dimer to be subjected to dimerization reaction under the irradiation of ultraviolet light in a second wavelength range, and the dimer is reduced to generate a reactant, so that the adhesive force of the adhesive is reduced, and the adhesive is convenient to strip.

Description

Technical Field

[0001] The present application relates to the technical field of photocurable materials, and in particular to a photocurable adhesive and a preparation method thereof, a display screen, and an electronic device. Background Art

[0002] Display screens, such as foldable screens, need to be bonded with optical films. When the optical films are damaged and fail, they need to be repaired. Therefore, the display panel usually uses a repair glue, i.e., an adhesive, to bond the optical film and the display panel together. During the repair process, the adhesion of the repair glue, i.e., the adhesive, can be reduced by heating, and the optical film can be torn off by a low peeling force, and replaced with a new optical film. However, if the heating temperature is too high, it is easy to affect the normal use of the display screen. Summary of the invention

[0003] The present application provides a photocurable adhesive and a preparation method thereof, a display screen and an electronic device. The adhesive can undergo cross-linking and curing and photodimerization reaction under ultraviolet light irradiation in a first wavelength range, and undergo dedimerization reaction under ultraviolet light irradiation in a second wavelength range, so that the adhesive can be used and peeled off easily.

[0004] Specifically, the present application is implemented through the following technical solutions:

[0005] The first object of the present application is to provide a photocurable adhesive, comprising the following components in parts by weight:

[0006] 50-100 parts of prepolymer monomer, 1-10 parts of active monomer containing photosensitive group, 1-3 parts of crosslinking agent and 0.1-1 part of initiator; the photosensitive group is set as a group for photodimerization reaction;

[0007] Wherein, when the photocurable adhesive is irradiated with ultraviolet light in a first wavelength range, the photosensitive groups undergo a photodimerization reaction to generate a dimer; when the photocurable adhesive is irradiated with ultraviolet light in a second wavelength range, the dimer undergoes a dedimerization reaction.

[0008] Optionally, the photosensitive group includes at least one of a cinnamoyl group, a coumarin group, an anthracene group or a chalcone group.

[0009] Optionally, the cross-linking agent includes at least one of ethylene glycol dimethacrylate, butylene glycol dimethacrylate or glycerol trimethacrylate.

[0010] Optionally, the initiator comprises a photoinitiator and / or a thermal initiator.

[0011] Optionally, the prepolymer monomer includes an acrylate monomer or an alkylene oxide monomer.

[0012] Optionally, the number average molecular weight of the prepolymer monomer is 1000-15000.

[0013] Optionally, the side chain and / or the end of the main chain of the prepolymer monomer has a first reactive group; and the reactive monomer containing a photosensitive group includes a second reactive group capable of chemically reacting with the first reactive group.

[0014] Optionally, the first reactive group includes at least one of a hydroxyl group, a carboxyl group, an amino group, an epoxy group or a carbon-carbon double bond; and the second reactive group includes at least one of a hydroxyl group, a carboxyl group or a halogen atom.

[0015] Optionally, the photocurable adhesive further comprises a capping agent for capping the polymer after the prepolymer monomer generates a polymer; the capping agent comprises at least one coupling reaction group selected from the group consisting of a hydroxyl group, a carboxyl group, a catechol group or an isocyanate group.

[0016] The second object of the present application is to provide a method for preparing any of the above-mentioned photocurable adhesives, comprising:

[0017] The prepolymer monomer, the active monomer containing a photosensitive group, the crosslinking agent and the initiator are mixed with the solvent according to a preset weight ratio, and stirred to obtain a liquid glue; then the liquid glue is irradiated with ultraviolet light in a first wavelength range for a first preset time, and crosslinked and cured to obtain an adhesive.

[0018] Optionally, the stirring temperature is 40-60° C.; and / or, the stirring time is 30-60 min; and / or, the first wavelength range is 300-400 nm; and / or, the first preset time is 3-10 min.

[0019] The third object of the present application is to provide a display screen, comprising a display panel and an optical film arranged on the light-emitting side of the display panel; a light-curing adhesive as described above is arranged between the display panel and the optical film;

[0020] The photocurable adhesive has a first adhesive force under the irradiation of ultraviolet light in a first wavelength range; the photocurable adhesive has a second adhesive force under the irradiation of ultraviolet light in a second wavelength range; the first adhesive force is greater than the second adhesive force.

[0021] The fourth purpose of the present application is to provide an electronic device, comprising the display screen as described above.

[0022] The technical solution provided by this application can achieve the following beneficial effects:

[0023] The present application provides a photocurable adhesive and a preparation method thereof, a display screen, and an electronic device. The photocurable adhesive can cause a polymerization reaction between prepolymer monomers under the irradiation of ultraviolet light in a first wavelength range to achieve crosslinking and curing of the adhesive; and cause a photodimerization reaction between photosensitive groups to generate dimers, thereby increasing the adhesion of the adhesive to a certain extent, making it easier to use. In addition, the photocurable adhesive provided by the present application can also cause a dedimerization reaction of the dimer under the irradiation of ultraviolet light in a second wavelength range, and reduce to generate reactants, thereby controlling the crosslinking density of the adhesive to decrease, reducing the adhesion of the adhesive, and making it easier to peel off. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a simplified structural diagram of a display screen shown in an exemplary embodiment of the present application.

[0025] Figure 2 This is a schematic diagram of the structure of a display screen shown in an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0026] In order to further understand the present application, the solar cell and the preparation method thereof provided by the present application are described in detail below in conjunction with the embodiments. The protection scope of the present application is not limited by the following embodiments.

[0027] The present application provides a photocurable adhesive comprising the following components in parts by weight:

[0028] 50-100 parts of prepolymer monomer, 1-10 parts of active monomer containing photosensitive group, 1-3 parts of crosslinking agent and 0.1-1 part of initiator; the photosensitive group is set as a group for photodimerization reaction;

[0029] Wherein, when the photocurable adhesive is irradiated with ultraviolet light in a first wavelength range, the photosensitive groups undergo a photodimerization reaction to generate a dimer; when the photocurable adhesive is irradiated with ultraviolet light in a second wavelength range, the dimer undergoes a dedimerization reaction.

[0030] The photocurable adhesive can cause free radical polymerization reaction between prepolymer monomers under the irradiation of ultraviolet light in the first wavelength range λ1, thereby realizing crosslinking and curing of the adhesive; and cause photodimerization reaction between photosensitive groups to generate dimers, thereby increasing the adhesion of the adhesive to a certain extent, making it easier to use. In addition, the photocurable adhesive provided by the present application can also cause dimers to undergo dedimerization reaction under the irradiation of ultraviolet light in the second wavelength range λ2, and reduce to generate reactants, thereby controlling the crosslinking density of the adhesive to decrease, reducing the adhesion of the adhesive, and facilitating peeling. Among them, the second wavelength range λ2 is smaller than the first wavelength range λ1.

[0031] In one embodiment, the photosensitive group includes at least one of a cinnamoyl group, a coumarin group, an anthracene group or a chalcone group.

[0032] For example, cinnamoyl and its derivatives can undergo [2+2] photocycloaddition, i.e., photodimerization, to form a dimer polymer under irradiation with ultraviolet light in a specific wavelength range of λ1, and the dimer polymer can undergo dedimerization reaction and be reduced to cinnamoyl and its derivatives under irradiation with ultraviolet light in a specific wavelength range of λ2 (λ2<λ1).

[0033] The reaction formula for the photodimerization of cinnamoyl and its derivatives is:

[0034]

[0035] Coumarin and its derivatives can undergo [2+2] photocycloaddition, i.e., photodimerization reaction to form cyclobutane dimer under the irradiation of ultraviolet light in the wavelength range of λ1=315-400nm. The cyclobutane dimer can undergo dedimerization reaction under the irradiation of ultraviolet light in the wavelength range of λ2=190-280nm and be reduced to coumarin and its derivatives.

[0036] The reaction formula of photodimerization of coumarin and its derivatives is:

[0037]

[0038] Anthracene and its derivatives can undergo [4+4] cycloaddition under ultraviolet light in the wavelength range λ1=300-400nm, i.e., anthracene dimerization reaction to generate a dimer polymer. The dimer polymer can undergo dedimerization reaction under irradiation in the wavelength range λ2=250-290nm and be reduced to anthracene and its derivatives.

[0039] The reaction formula for photodimerization of anthracene and its derivatives is:

[0040]

[0041] Of course, the specific types of photosensitizing groups are not limited thereto, as long as they can undergo photodimerization reaction under ultraviolet light within a specific wavelength range λ1 and undergo dedimerization reaction under ultraviolet light within a specific wavelength range λ2 (λ2<λ1).

[0042] In one embodiment, the crosslinking agent includes at least one of ethylene glycol dimethacrylate, butylene glycol dimethacrylate or glycerol trimethacrylate. Thus, by adding the crosslinking agent, the modulus of the material can be increased, thereby further improving the cohesive strength of the adhesive to improve the adhesion of the adhesive.

[0043] It should be noted that the specific selection of the crosslinking agent is not limited to this, and can be adjusted according to actual production requirements. For example, the crosslinking agent can also be selected from phenolic resin and / or epoxy resin to increase the crosslinking network size and crosslinking density of the adhesive to further improve the adhesion and cohesion of the adhesive.

[0044] In one embodiment, the initiator includes a photoinitiator and / or a thermal initiator. Exemplarily, the photoinitiator includes but is not limited to at least one of 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinyl-1-propanone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxy-cyclohexyl-phenyl ketone, 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinylbenzylphenyl)butanone or phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide. Exemplarily, the thermal initiator includes but is not limited to azobisisobutyronitrile or diacyl peroxide.

[0045] After absorbing ultraviolet light energy within a certain range of wavelengths, the photoinitiator can generate free radicals, causing the prepolymer monomers to polymerize, crosslink and cure to obtain an adhesive. The thermal initiator can act as a catalyst to initiate the polymerization, crosslinking and curing of the prepolymer monomers under high temperature conditions to obtain an adhesive.

[0046] It should be noted that, since the absorption wavelength range of the photoinitiator is relatively wide, in order to prevent the photoinitiator from quickly polymerizing, cross-linking and curing the prepolymer monomers after absorbing the energy of light, thereby affecting the photodimerization reaction between the active monomers containing the photosensitive group, it is first ensured that the photodimerization reaction between the active monomers containing the photosensitive group is basically completed, and then the photoinitiator is added to polymerize, cross-link and cure the prepolymer monomers to obtain the adhesive.

[0047] In one embodiment, the prepolymer monomer includes an acrylate monomer or an alkylene oxide monomer. Exemplarily, the acrylate monomer includes but is not limited to at least one of isooctyl acrylate, hydroxyethyl acrylate, 4-hydroxybutyl acrylate, 2-phenoxyethyl acrylate, cyclotrimethylolpropane formal acrylate, 1,6-hexanediol diacrylate, trimethylolpropane trimethacrylate or phenoxyethylene glycol acrylate. Exemplarily, the alkylene oxide monomer includes but is not limited to at least one of propylene oxide, epichlorohydrin, epibromopropane or 3-hydroxypropylene oxide.

[0048] Of course, in other embodiments, the prepolymer monomer may also include isocyanate and a polyol containing at least two active hydrogen atoms, and the isocyanate-terminated polymer is generated by reacting the polyol containing at least two active hydrogen atoms with the isocyanate; and the isocyanate-terminated polymer is reacted with the polyol containing at least two isocyanate groups to form a polyurethane. For example, the isocyanate includes but is not limited to at least one of toluene diisocyanate, hydrogenated phenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate or phenylmethane diisocyanate; and the polyol includes but is not limited to at least one of polyether polyol, polyester polyol or polyolefin polyol.

[0049] In one embodiment, the number average molecular weight of the prepolymer monomer is 1000 to 15000. This can prevent the molecular weight of the prepolymer from being too large, which may lead to poor viscosity of the adhesive formed after polymerization.

[0050] In one embodiment, the end of the side chain and / or main chain of the prepolymer monomer has a first reactive group; the reactive monomer containing a photosensitive group includes a second reactive group that can react chemically with the first reactive group. Thus, the reactive monomer containing a photosensitive group can be polymerized to the end of the side chain and / or main chain of the prepolymer monomer through the reaction of the second reactive group with the first reactive group, so as to further improve the adhesion of the adhesive. In one embodiment, the end of the side chain and main chain of the prepolymer monomer has different types of first reactive groups. Thus, the reaction of the second reactive group with different types of first reactive groups can be controlled to control the polymerization of the reactive monomer containing a photosensitive group to the side chain or main chain of the prepolymer monomer.

[0051] Illustratively, if the second reactive group reacts with the first reactive group at the end of the side chain of the prepolymer monomer but does not react with the first reactive group at the end of the main chain of the prepolymer monomer, the reactive monomer containing the photosensitive group can be controlled to polymerize to the side chain of the prepolymer monomer instead of to the main chain of the prepolymer monomer; and if the second reactive group reacts with the first reactive group at the end of the main chain of the prepolymer monomer but does not react with the first reactive group at the end of the side chain of the prepolymer monomer, the reactive monomer containing the photosensitive group can be controlled to polymerize to the main chain of the prepolymer monomer instead of to the side chain of the prepolymer monomer.

[0052] In one embodiment, the first reactive group includes at least one of a hydroxyl group, a carboxyl group, an amino group, an epoxy group or a carbon-carbon double bond; the second reactive group includes at least one of a hydroxyl group, a carboxyl group or a halogen atom.

[0053] For example, when the first reactive group is a carboxyl group, the second reactive group may be a hydroxyl group, and an esterification reaction occurs between the carboxyl group and the hydroxyl group to polymerize the reactive monomer containing a photosensitive group and the prepolymer monomer; for another example, when the first reactive group is an amino group, the second reactive group may be a carboxyl group, and an amide reaction occurs between the amino group and the carboxyl group to polymerize the reactive monomer containing a photosensitive group and the prepolymer monomer; for another example, when the first reactive group is an epoxy group, the second reactive group may also be a carboxyl group, and an epoxycarboxylation reaction occurs between the epoxy group and the carboxyl group to polymerize the reactive monomer containing a photosensitive group and the prepolymer monomer.

[0054] Of course, the selection of specific group types of the first active group and the second active group is not limited thereto, as long as the first active group and the second active group can undergo a chemical reaction so that the active monomer containing the photosensitive group can be polymerized with the prepolymer monomer.

[0055] In one embodiment, the crosslinking agent has at least two first reactive groups, which are used to chemically react with the second reactive groups of the reactive monomers containing photosensitive groups, so as to connect the reactive monomers containing photosensitive groups in the crosslinking agent and form a double photosensitive group, a triple photosensitive group or even a larger number of photosensitive groups on the crosslinking agent. This facilitates the photosensitive groups formed on the crosslinking agent to undergo photodimerization reaction with the photosensitive groups formed on the prepolymer to generate dimers during the crosslinking and curing process of obtaining the adhesive under the irradiation of ultraviolet light in the first wavelength range λ1. This also facilitates the reduction and decomposition of the dimers during the dedimerization reaction under the irradiation of ultraviolet light in the second wavelength range λ2.

[0056] In one embodiment, the photocurable adhesive further comprises a capping agent for capping the polymer after the prepolymer monomer generates the polymer; the capping agent comprises at least one coupling reaction group selected from hydroxyl, carboxyl, catechol group or isocyanate group, thereby further improving the viscosity of the photocurable adhesive.

[0057] The present application also provides a method for preparing a photocurable adhesive, comprising: mixing a prepolymer monomer, an active monomer containing a photosensitive group, a crosslinking agent and an initiator with a solvent in a preset weight ratio, and stirring to obtain a liquid adhesive; then irradiating the liquid adhesive with ultraviolet light in a first wavelength range for a first preset time, and crosslinking and curing to obtain an adhesive.

[0058] By mixing the above components in a certain weight ratio in a solvent and stirring, a uniform system can be formed, and then the adhesive can be cross-linked and cured by irradiating ultraviolet light in a first wavelength range.

[0059] In one embodiment, a prepolymer monomer and a cross-linking agent are mixed with a solvent in a preset weight ratio to form a polymer, and then an active monomer containing a photosensitive group is added to the polymer to polymerize the active monomer containing the photosensitive group to the side chain and / or main chain of the polymer; then an initiator is added to perform cross-linking and curing to obtain an adhesive.

[0060] In one embodiment, after the prepolymer monomer, the active monomer containing a photosensitive group, the crosslinking agent and the initiator are mixed with the solvent in a preset weight ratio to form a mixed solution, an antioxidant can be added to the mixed solution to form a uniform transparent system to prevent the adhesive obtained by subsequent curing from yellowing. Exemplarily, the antioxidant includes but is not limited to phosphite and / or butylated hydroxytoluene.

[0061] In one embodiment, the solvent is a non-reactive solvent, including but not limited to at least one of a halogenated hydrocarbon solvent, a ketone solvent, an alcohol solvent, an ester solvent or a hydrocarbon solvent. For example, the halogenated hydrocarbon solvent includes but is not limited to at least one of dichloromethane, dichloroethane or chloroform; the ketone solvent includes but is not limited to acetone and / or butanone; the alcohol solvent includes but is not limited to ethanol and / or butanol; the ester solvent includes but is not limited to ethyl acetate and / or butyl acetate; the hydrocarbon solvent includes but is not limited to an aliphatic hydrocarbon solvent and / or an aromatic hydrocarbon solvent.

[0062] In one embodiment, the stirring temperature is 40-60°C; thereby, it is avoided that the adhesive is easily decomposed due to high temperature, resulting in damage to the material structure, and that the cross-linking density of the adhesive is too low due to low temperature. In one embodiment, the stirring time is 30-60 minutes; thereby, it is avoided that the viscosity of the adhesive fails due to too long stirring time, resulting in a decrease in the viscosity of the system. It is also avoided that insufficient stirring time makes it difficult to form a uniform system. It should be noted that stirring includes but is not limited to magnetic stirring and / or mechanical stirring.

[0063] In one embodiment, the first wavelength range is 300-400 nm; in one embodiment, the first preset time is 3-10 min. Thus, it is possible to avoid the aging and debonding of the adhesive due to a long UV curing time, and to avoid the poor curing effect of the adhesive due to a short UV curing time.

[0064] In one embodiment, when the viscosity of the adhesive needs to be reduced, ultraviolet light in the second wavelength range is irradiated on the adhesive for a second preset time, so that the adhesive undergoes a de-dimerization reaction, thereby smoothly reducing the viscosity of the adhesive to complete the peeling. Exemplarily, the second wavelength range is 190 to 280 nm; the second preset time is 3 to 10 minutes.

[0065] See also Figure 1The present application also provides a display screen, comprising a display panel 3 and an optical film 1 arranged on the light-emitting side of the display panel 3; a light-curing adhesive 2 as described above is arranged between the display panel 3 and the optical film 1;

[0066] The photocurable adhesive 2 has a first adhesive force when exposed to ultraviolet light in a first wavelength range; the photocurable adhesive 2 has a second adhesive force when exposed to ultraviolet light in a second wavelength range; the first adhesive force is greater than the second adhesive force.

[0067] For example, liquid glue may be sprayed on the display panel 3 and irradiated with an ultraviolet light source in the wavelength range of 365 nm for 7 minutes to make the prepolymer monomer undergo a polymerization reaction, the photosensitive group undergo a photodimerization reaction, and the adhesive 2 is formed after cross-linking and curing, so as to ensure that the display panel 3 and the adhesive 2 are tightly bonded together. Then, the optical film 1 is pressed onto the adhesive 2 to adhere the optical film 1 to the display panel 3.

[0068] When the optical film 1 needs to be removed, an ultraviolet light source with a wavelength of 254 nm is used for irradiation for 10 minutes to cause a dedimerization reaction of the adhesive 2 , thereby smoothly peeling the optical film 1 from the display panel 3 .

[0069] In one embodiment, before applying the adhesive 2 to the display panel 3, some surfactants such as silicone additives, including but not limited to polysiloxane, can be sprayed onto the display panel 3. This can reduce the surface binding energy of the display panel 3 and improve the adhesion between the adhesive 2 and the display panel 3.

[0070] In one embodiment, the optical film 1 includes but is not limited to at least one of anti-reflection, anti-fingerprint, anti-scratch or anti-glare functions.

[0071] The present application also provides an electronic device, comprising the display screen as described above. Exemplarily, the display screen is a flexible folding screen.

[0072] like Figure 2As shown, a layer of UTG glass is first pasted on the light-emitting side of the display panel (Panel is used as an example in the figure) of the folding screen through ordinary glue (OCA2 is used as an example in the figure); then a layer of HC-PET film is pasted on the side of the UTG glass facing away from the display panel panel through ordinary glue (OCA1 is used as an example in the figure); then, a layer of optical film (AR film is used as an example in the figure) is pasted on the side of the HC-PET film facing away from the display panel panel using the adhesive provided by the present application to form a repair glue (OCA0 is used as an example in the figure). Since the hardness of the outermost optical film (i.e., AR film) is relatively high, it is easy to be damaged and fail during multiple bending processes. When the optical film (i.e., AR film) is repaired, the adhesive provided by the present application can adjust the viscosity of the adhesive under the condition of ultraviolet light irradiation after forming the repair glue, without the need to use high temperature to regulate the viscosity of the adhesive. Therefore, when the subsequent electronic equipment is subjected to the whole machine bending reliability test, even if the temperature of the test environment is high, it basically does not affect the viscosity of the adhesive.

[0073] In addition, since the display panel is usually made of electroluminescent materials (hereinafter referred to as "EL materials"), although the existing heating method can reduce the adhesion of the adhesive, heating is also likely to damage the internal molecules of the EL material, thereby affecting the display panel's conversion effect of converting electrical energy into light energy. Figure 2 As shown, the present application can adjust the viscosity of the adhesive under the condition of ultraviolet light irradiation without the need to use high temperature to regulate the viscosity of the adhesive. In addition, UTG glass and HC-PET film are provided between the display panel Panel and the repair adhesive layer formed by the adhesive provided by the present application (OCA0 is used as an example in the figure), which can have a certain isolation effect on ultraviolet light. Therefore, when it is necessary to tear off the optical film, even if ultraviolet light is used for irradiation, it is basically difficult to damage the molecular structure of the EL material of the display panel.

[0074] Example 1

[0075] 30 parts by weight of isooctyl acrylate, 20 parts by weight of hydroxyethyl acrylate, 2 parts by weight of 6-carboxycoumarin, 2 parts by weight of ethylene glycol dimethacrylate, 0.2 parts by weight of azobisisobutyronitrile and 1 part by weight of butylated hydroxytoluene were weighed and added to 30 parts by weight of ethyl acetate solvent, with each part by weight being 2 g. The mixture was stirred at 50° C. for 30 min to form a liquid glue, and irradiated with an ultraviolet light source in a wavelength range of 365 nm for 7 min to cure the adhesive.

[0076] Example 2

[0077] 50 parts by weight of isooctyl acrylate, 50 parts by weight of 4-hydroxybutyl acrylate, 10 parts by weight of 6-carboxycoumarin, 3 parts by weight of butylene dimethacrylate, 1 part by weight of azobisisobutyronitrile and 3 parts by weight of dibutylhydroxytoluene were weighed and added to 60 parts by weight of ethyl acetate solvent, with each part by weight being 2 g. The mixture was stirred at a temperature of 50° C. for 30 min to form a liquid glue, and irradiated with an ultraviolet light source in a wavelength range of 365 nm for 5 min to cure the adhesive.

[0078] Example 3

[0079] 50 parts by weight of isooctyl acrylate, 20 parts by weight of hydroxyethyl acrylate and 3 parts by weight of glycerol trimethacrylate were weighed and added to 40 parts by weight of ethyl acetate solvent, and stirred at 50° C. for 10 minutes; then 5 parts by weight of 3-(9-anthryl)propionic acid were added and stirred at 50° C. for 10 minutes; then 0.5 parts by weight of azobisisobutyronitrile and 1 part by weight of butylated hydroxytoluene were added and stirred at 50° C. for 10 minutes to form a liquid glue, and an ultraviolet light source with a wavelength range of 365 nm was used for irradiation for 3 minutes to cure the adhesive.

[0080] Example 4

[0081] 50 parts by weight of isooctyl acrylate, 20 parts by weight of hydroxyethyl acrylate and 3 parts by weight of ethylene glycol dimethacrylate were weighed and added to 40 parts by weight of ethyl acetate solvent, and stirred at 50° C. for 10 minutes; then 5 parts by weight of 3-(9-anthryl)propionic acid were added and stirred at 50° C. for 10 minutes; then 0.5 parts by weight of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and 1 part by weight of butylated hydroxytoluene were added and stirred at 50° C. for 10 minutes to form a liquid glue, and an ultraviolet light source with a wavelength range of 400 nm was used for irradiation for 10 minutes to cure the adhesive.

[0082] Example 5

[0083] 50 parts by weight of alkylene oxide, 20 parts by weight of hydroxyethyl acrylate and 3 parts by weight of ethylene glycol dimethacrylate were weighed and added to 40 parts by weight of ethyl acetate solvent, and stirred at 60° C. for 20 minutes; then 5 parts by weight of 3-(9-anthryl)propionic acid were added and stirred at 50° C. for 20 minutes; then 0.5 parts by weight of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and 1 part by weight of butylated hydroxytoluene were added and stirred at 50° C. for 20 minutes to form a liquid glue, and an ultraviolet light source with a wavelength range of 365 nm was used for irradiation for 7 minutes to cure the adhesive.

[0084] Comparative Example

[0085] 30 parts by weight of isooctyl acrylate, 20 parts by weight of hydroxyethyl acrylate, 2 parts by weight of ethylene glycol dimethacrylate, 0.2 parts by weight of azobisisobutyronitrile and 1 part by weight of butylated hydroxytoluene were added to 30 parts by weight of ethyl acetate solvent, with each part by weight being 2 g. The mixture was stirred at 50° C. for 30 min to form a liquid glue, and irradiated with an ultraviolet light source in a wavelength range of 365 nm for 7 min to cure the adhesive.

[0086] Performance Testing

[0087] Adhesion test: According to the test method of GB / T 2791-1995 standard, the adhesives prepared in Examples 1-5 and Comparative Example 1 were subjected to adhesion mechanical tests. The test data are shown in Table 1.

[0088] High water angle surface peeling force test: According to the ASMTD3330 international standard, the liquid glue prepared in Examples 1-5 was sprayed on a 0.05 mm transparent PET film to form a thin film, and was rolled and applied to a UTG glass plate with a 2KG roller at a speed of 600MM / MIN, allowed to stand for 20 minutes, and then irradiated with 254nm ultraviolet light for 7 minutes for dedimerization reaction, and then the peeling adhesion of the 180° high water angle surface was tested using a tensile testing machine; the adhesive prepared in Comparative Example 1 was applied to a 0.05 mm transparent PET film to form a thin film, and was rolled and applied to a glass plate with a 2KG roller at a speed of 600mm / min, allowed to stand for 20 minutes, and then heated to 70°C to react with the adhesive, and then the peeling adhesion of the 180° high water angle surface was tested using a tensile testing machine.

[0089] Modulus test: According to the test method of ASTM D 3983-98 standard, the adhesives prepared in Examples 1-5 and Comparative Example 1 were tested for shear modulus of 150 μm film at low temperature (-55°C), room temperature (24°C), and high temperature (125°C) using a dynamic mechanical analyzer HR-2. The test data are detailed in Table 1.

[0090] Table 1

[0091]

[0092] From the data in Table 1, it can be seen that the adhesion of the adhesive provided in this application is greater than 15N / inch, the peel force on the high water angle surface is greater than 80gf / inch; the room temperature modulus is less than or equal to 50kPa; the low temperature modulus is less than or equal to 300kPa; and the high temperature modulus is greater than or equal to 10kPa.

[0093] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A light-curing adhesive, characterized in that: The composition comprises the following components in parts by weight: 50-100 parts of prepolymer monomer, 1-10 parts of active monomer containing photosensitive group, 1-3 parts of crosslinking agent and 0.1-1 part of initiator; the photosensitive group is set as a group for photodimerization reaction; Wherein, when the photocurable adhesive is irradiated with ultraviolet light in a first wavelength range, the photosensitive groups undergo a photodimerization reaction to generate a dimer; when the photocurable adhesive is irradiated with ultraviolet light in a second wavelength range, the dimer undergoes a dedimerization reaction.

2. The light-curing adhesive according to claim 1, characterized in that: The photosensitive group includes at least one of a cinnamoyl group, a coumarin group, an anthracene group or a chalcone group.

3. The light-curing adhesive according to claim 1, characterized in that: The cross-linking agent includes at least one of ethylene glycol dimethacrylate, butylene glycol dimethacrylate or glycerol trimethacrylate.

4. The light-curing adhesive according to claim 1, characterized in that: The initiator includes a photoinitiator and / or a thermal initiator.

5. The light-curing adhesive according to claim 1, characterized in that: The prepolymer monomers include acrylate monomers or alkylene oxide monomers.

6. The light-curing adhesive according to claim 5, characterized in that: The number average molecular weight of the prepolymer monomer is 1000-15000.

7. The light-curing adhesive according to claim 1, characterized in that: The side chain and / or the end of the main chain of the prepolymer monomer has a first reactive group; the reactive monomer containing a photosensitive group includes a second reactive group that can chemically react with the first reactive group.

8. The light-curing adhesive according to claim 7, characterized in that: The first active group includes at least one of a hydroxyl group, a carboxyl group, an amino group, an epoxy group or a carbon-carbon double bond; the second active group includes at least one of a hydroxyl group, a carboxyl group or a halogen atom.

9. The light-curing adhesive according to any one of claims 1 to 8, characterized in that: The photocurable adhesive further comprises a capping agent for capping the polymer after the prepolymer monomer generates the polymer; the capping agent comprises at least one coupling reaction group selected from hydroxyl, carboxyl, catechol group or isocyanate group.

10. A method for preparing a light-curing adhesive according to any one of claims 1 to 9, characterized in that: include: The prepolymer monomer, the active monomer containing a photosensitive group, the crosslinking agent and the initiator are mixed with the solvent according to a preset weight ratio, and stirred to obtain a liquid glue; then the liquid glue is irradiated with ultraviolet light in a first wavelength range for a first preset time, and crosslinked and cured to obtain an adhesive.

11. The preparation method according to claim 10, characterized in that: The stirring temperature is 40-60° C.; and / or, the stirring time is 30-60 min; and / or, the first wavelength range is 300-400 nm; and / or, the first preset time is 3-10 min.

12. A display screen, comprising a display panel and an optical film arranged on a light emitting side of the display panel; characterized in that: A light-curable adhesive as claimed in any one of claims 1 to 9 is provided between the display panel and the optical film; The photocurable adhesive has a first adhesive force under the irradiation of ultraviolet light in a first wavelength range; the photocurable adhesive has a second adhesive force under the irradiation of ultraviolet light in a second wavelength range; the first adhesive force is greater than the second adhesive force.

13. An electronic device, characterized in that: Comprising the display screen as claimed in claim 12.

Images