TW202233791A - Adhesive composion and method for manufacturing bonded body using same - Google Patents

Abstract

To provide an adhesive composition which can maintain an applied shape after UV irradiation and has good adhesive strength after curing, and a method for producing a bonded body using the same. The adhesive composition contains: 45-70 mass% of an epoxy resin; a first (meth)acrylate component of at least one selected from the group consisting of aromatic (meth)acrylates, alicyclic (meth)acrylates and heterocyclic (meth)acrylates; a second (meth)acrylate component comprising a hydroxyl group-containing (meth)acrylate; a radical photopolymerization initiator; and a cationic photopolymerization initiator. The adhesive composition may contain: a hydrogenated epoxy resin in an amount greater than 30 mass% and less than or equal to 70 mass%; a first (meth)acrylate component of at least one selected from the group consisting of aromatic (meth)acrylates, alicyclic (meth)acrylates and heterocyclic (meth)acrylates; a second (meth)acrylate component comprising a hydroxyl group-containing (meth)acrylate; a radical photopolymerization initiator; and a cationic photopolymerization initiator.

Description

Adhesive composition and manufacturing method of bonded body using the same

The present technology relates to an adhesive composition and a method for producing a bonded body using the same.

The following technologies are known: using optically transparent adhesives such as OCR (Optical Clear Resin) or LOCA (Liquid Optically Clear Adhesive, Liquid Optical Clear Adhesive) to separate the image display device from the front cover, the image display device and the image display device, respectively. Adherents such as the touch panel, the front cover, and the touch panel are bonded and fixed to each other (for example, Patent Documents 1 to 3). Among them, about the curing method of the UV (Ultraviolet, ultraviolet) impermeable part, a UV delayed curing type adhesive is also proposed. In addition, in recent years, due to the appearance of displays other than rectangular, the necessity of special-shaped application of adhesives has been increasing. As one of the solutions, ink jet coating can be mentioned. Adhesives used in inkjet coating are required to have low viscosity, and usually monomers are the main component.

In Patent Documents 1 and 2, resin compositions containing a polyfunctional epoxy resin, a monofunctional epoxy resin, and a polyfunctional oxetane resin are described as a UV retarded curing type adhesive. Patent Document 3 describes a photocurable resin composition containing a radical polymerizable group-containing compound, a cationically polymerizable group-containing compound, a photoradical initiator, and a photoacid generator, and containing free radicals. The content of the compound containing a cationic polymerizable group is more than that of the compound containing a cationic polymerizable group. The photoradical initiator is α-hydroxyalkylphenone, which is a photoradical initiator and diphenylethyl ether. Diketone methyl ketal (benzil methylketal) is at least one of photo-radical initiators, and the mass ratio of photo-radical initiator and photo-acid generator (photo-radical initiator/photo-acid generator) is 0.5 to 30.

Since the UV curable resin compositions described in Patent Documents 1 and 2 are epoxy-cationic curing systems, curing starts later than acrylic-radical curing systems. In particular, the hardening of monofunctional epoxy monomers starts late. Therefore, in the case of using the epoxy-cationic curing adhesives described in Patent Documents 1 and 2 as a low-viscosity inkjet coating adhesive, curing does not start immediately after UV irradiation, so it is difficult to maintain the coating. Cloth shape concerns.

On the other hand, although the conventional acrylic-radical curing UV curable resin composition is not easily deformed after UV irradiation, if the elastic modulus after curing is high, it is difficult for the adherends to bounce back from each other. Tendency to fit. Therefore, the elastic modulus of the conventional acrylic-radical curing UV curable resin composition after curing must be low, and it is difficult to obtain sufficient bonding strength. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 5919574 [Patent Document 2] Japanese Patent No. 6080064 [Patent Document 3] Japanese Patent Laid-Open No. 2017-218515

[The problem to be solved by the invention]

The present technology is proposed in view of such a conventional situation, and provides an adhesive composition which can maintain the coating shape after UV irradiation and has a good adhesive strength after curing, and a manufacturing method of a bonded body using the same. [Technical means to solve the problem]

The adhesive composition of the present technology contains: 45 to 70% by mass of epoxy resin; selected from aromatic (meth)acrylates, alicyclic (meth)acrylates, and heterocyclic (meth)acrylates At least one first (meth)acrylate component in the group consisting of; the second (meth)acrylate component consisting of a hydroxyl group-containing (meth)acrylate; a radical photopolymerization initiator; and a cationic Photopolymerization initiator.

The adhesive composition of the present technology contains: more than 30 mass % and 70 mass % or less of a hydrogenated epoxy resin; selected from aromatic (meth)acrylates, alicyclic (meth)acrylates, and heterocyclic ( At least one first (meth)acrylate component in the group consisting of meth)acrylates; The second (meth)acrylate component consisting of hydroxyl-containing (meth)acrylates; Radical photopolymerization an initiator; and a cationic photopolymerization initiator.

The manufacturing method of the laminated body of the present technology has the following steps: step A, coating the above-mentioned adhesive composition on the first adherend to form an adhesive composition layer; step B, irradiating the adhesive composition layer with ultraviolet rays to form the adhesive composition layer. and step C, disposing a second adherend on the surface of the adhesive hardening layer, and joining the first adherend and the second adherend through the adhesive hardening layer. [Effect of invention]

The present technology can provide an adhesive composition which can maintain the coating shape after UV irradiation and has good adhesive strength after curing.

The adhesive composition of the present technology contains: 45 to 70% by mass of epoxy resin; selected from aromatic (meth)acrylates, alicyclic (meth)acrylates, and heterocyclic (meth)acrylates At least one first (meth)acrylate component in the group consisting of; the second (meth)acrylate component consisting of a hydroxyl group-containing (meth)acrylate; a radical photopolymerization initiator; and a cationic Photopolymerization initiator.

FIG. 1 is a graph for illustrating the change of the elastic modulus of the adhesive composition with respect to time. The horizontal axis in FIG. 1 represents time, and the vertical axis represents elastic modulus. In addition, A in FIG. 1 shows the elastic modulus (Dahlquist standard) which can be attached. The curve (i) in FIG. 1 shows the change of the elastic modulus with respect to time when the conventional epoxy-cationic curing UV curable resin composition described in, for example, the above-mentioned Patent Documents 1 and 2 is used. The curve (ii) in FIG. 1 shows the change of the elastic modulus with time when a conventional acrylic-radical-curable UV-curable resin composition is used. Moreover, the curve (iii) in FIG. 1 shows the change of the elastic modulus with respect to time when the adhesive composition of this technique is used (epoxy-cationic hardening system and acrylic-radical hardening system are used together).

The adhesive composition of the present technology contains the first (meth)acrylate component and a radical photopolymerization initiator, as shown in B in FIG. 1, curing starts immediately after UV irradiation, so after UV irradiation , showing immediate adhesion and shape retention. In addition, the epoxy resin in the adhesive composition of the present technology does not completely harden immediately after UV irradiation, but contributes to lowering the elasticity of the adhesive composition as a plasticizing component. In this way, the adhesiveness and adhesion of the adhesive composition of the present technology after UV irradiation are improved.

In addition, the adhesive composition of the present technology exhibits delayed curing properties by containing an epoxy resin and a cationic photopolymerization initiator. Therefore, after UV irradiation, the adhesive composition of the present technology starts delayed hardening by being placed at room temperature (and heated if necessary), and can exhibit higher adhesive strength.

Furthermore, the adhesive composition of this technology can express adhesiveness (adhesive force) and delayed hardening more effectively by using the 1st (meth)acrylate component and the 2nd (meth)acrylate component together.

In this way, the adhesive composition of the present technology can maintain the coating shape after UV irradiation, and can also make the adhesive strength after curing good.

Hereinafter, specific examples of the constituent elements of the adhesive composition of the present technology will be described.

＜Epoxy resin＞ The epoxy resin may be a monofunctional epoxy compound having one epoxy group in one molecule, or a polyfunctional epoxy compound having two or more epoxy groups in one molecule. In particular, from the viewpoint of reactivity, the epoxy resin is preferably a polyfunctional epoxy compound, more preferably a bifunctional epoxy resin.

The epoxy resin may be solid at room temperature, or liquid at room temperature. Normal temperature refers to the range of 15 to 25°C specified in JIS K 0050:2019 (General Principles of Chemical Analysis Methods). The epoxy group which the epoxy resin has may be an alicyclic epoxy group or a non-alicyclic epoxy group.

Specific examples of epoxy resins include bisphenol-type epoxy compounds such as polybutadiene epoxy resins, bisphenol A-type epoxy resins, and bisphenol F-type epoxy resins; naphthalene-type epoxy compounds, fatty family epoxy compounds, biphenyl type epoxy compounds, glycidylamine type epoxy compounds, hydrogenated bisphenol A type epoxy compounds and other alcohol type epoxy compounds; epoxy modified polysiloxane, phenol novolac type epoxy compounds Compounds, novolak-type epoxy compounds such as cresol novolak-type epoxy compounds; alicyclic epoxy compounds, polyfunctional epoxy compounds, glycidyl ether-type epoxy compounds, glycidyl ester-type epoxy compounds Compounds, halogenated epoxy compounds such as brominated epoxy compounds; rubber modified epoxy compounds; urethane modified epoxy compounds; epoxidized polybutadiene, epoxidized styrene-butadiene-styrene block copolymer ; Epoxy-containing polyester compounds; Epoxy-containing polyurethane compounds; Epoxy-containing acrylic compounds, etc. Among these, a bisphenol F-type epoxy resin is preferable from the viewpoint of maintaining the delayed curability of the adhesive composition after UV irradiation.

Moreover, as an epoxy resin, a hydrogenated epoxy resin can also be used. Hydrogenated epoxy resin is preferable from the viewpoint of the penetration rate or coloring resistance after the adhesive composition is hardened.

The epoxy equivalent of the epoxy resin may be, for example, 150 to 300 g/eq, or 180 to 220 g/eq.

The viscosity of the epoxy resin at 25°C is preferably 500-10,000 mPa·s.

Examples of epoxy resin products include jER YX8000, YX8034 (the above are manufactured by Mitsubishi Chemical Corporation), EPICLON EXA-830CRP (manufactured by DIC Corporation), and the like. An epoxy resin may be used individually by 1 type, and may use 2 or more types together.

The content of the epoxy resin in the adhesive composition is 45% by mass or more, 50% by mass or more, or 53% by mass or more. By setting the content of the epoxy resin in the adhesive composition to be 45% by mass or more, high adhesive strength can be expressed after UV irradiation. The upper limit of the content of the epoxy resin in the adhesive composition is 70% by mass or less, 65% by mass or less, or 60% by mass or less. By making the content of the epoxy resin in the adhesive composition 70% by mass or less, other components (for example, the first (meth)acrylate component or the second (meth)acrylate component) do not become relatively If it is too small, adhesion and shape retention may be exhibited after UV irradiation. It is especially preferable that the content of the hydrogenated epoxy resin in the adhesive composition satisfies the above numerical range. Furthermore, when the adhesive composition contains two or more epoxy resins, it is preferable that the total amount of the epoxy resins satisfies the above numerical range.

<1st (meth)acrylate component> The first (meth)acrylate component is selected from the group consisting of aromatic (meth)acrylates, alicyclic (meth)acrylates, and heterocyclic (meth)acrylates. The 1st (meth)acrylate component may be used individually by 1 type, and may use 2 or more types together. The first (meth)acrylate component may be monofunctional, or may be bifunctional or more, but preferably monofunctional.

The aromatic (meth)acrylate is a (meth)acrylate having an aromatic hydrocarbon group. The carbon number of the aromatic hydrocarbon group in an aromatic (meth)acrylate may be 6-30, and may be 6-18. The aromatic hydrocarbon group may have a monocyclic structure or a polycyclic structure. The aromatic hydrocarbon group may have a substituent or may be unsubstituted. Specific examples of aromatic (meth)acrylates include benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, and phenoxypolyethylene glycol. Alcohol (meth)acrylate, nonylphenoxy polyethylene glycol (meth)acrylate, phenoxy polypropylene glycol (meth)acrylate, 2-(meth)acryloyl phthalate Ethyl-2-hydroxypropyl ester, 2-hydroxy-3-phenoxypropyl (meth)acrylate. Among them, from the viewpoint of more effectively expressing the adhesive force and shape retention of the adhesive composition after UV irradiation, benzyl (meth)acrylate is preferred, and benzyl acrylate is more preferred. As a product example of an aromatic (meth)acrylate, Viscoat 160 (made by Osaka Organic Chemical Industry Co., Ltd.) can be mentioned.

Alicyclic (meth)acrylate is (meth)acrylate which has an alicyclic structure. The number of carbon atoms constituting the alicyclic structure in the alicyclic (meth)acrylate may be, for example, 4-30, 4-20, 4-10, or 4-8. The alicyclic structure in the alicyclic (meth)acrylate may be a monocyclic structure or a polycyclic structure. The alicyclic structure in the alicyclic (meth)acrylate may be saturated or unsaturated. The alicyclic hydrocarbon group may have a substituent or may be unsubstituted. Specific examples of alicyclic (meth)acrylates include cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentyl (meth)acrylate, (meth)acrylate Dicyclopentenyl acrylate, Dicyclopentenyl (meth)acrylate, Dicyclopentenyloxyethyl acrylate, Adamantyl (meth)acrylate, 2-Alkyl (meth)acrylate- 2-adamantyl ester, 3-hydroxy-1-adamantyl (meth)acrylate, 1-perfluoroadamantyl (meth)acrylate, etc. Among these, from the viewpoint of more effectively expressing the adhesive force and shape retention of the adhesive composition after UV irradiation, cyclohexyl (meth)acrylate is preferred, and cyclohexyl acrylate is more preferred . As a product example of an alicyclic (meth)acrylate, Viscoat 155 (made by Osaka Organic Chemical Industry Co., Ltd.) can be mentioned.

The heterocyclic (meth)acrylate has, for example, at least one of a nitrogen atom, an oxygen atom, and a sulfur atom as a heteroatom of the heterocyclic ring. The number of carbon atoms constituting the heterocycle may be 3-10 or 3-8. The heterocycle may have a monocyclic structure or a polycyclic structure. The heterocycle may have a substituent or may be unsubstituted. Specific examples of the heterocyclic (meth)acrylate include tetrahydrofurfuryl (meth)acrylate, 4-tetrahydropyranyl acrylate, 2-tetrahydropyranyl acrylate, and the like. Among these, from the viewpoint of more effectively expressing the adhesive force and shape retention of the adhesive composition after UV irradiation, tetrahydrofurfuryl (meth)acrylate is preferred, and tetrahydroacrylate is more preferred. furfuryl ester. As a product example of a heterocyclic (meth)acrylate, Viscoat 150 (made by Osaka Organic Chemical Industry Co., Ltd.) can be mentioned.

The content of the first (meth)acrylate component in the adhesive composition is preferably at least 20% by mass, may be at least 25% by mass, may be at least 30% by mass, may be at least 35% by mass, or may be 40% by mass or more. By making content of the 1st (meth)acrylate component in an adhesive composition 20 mass % or more, the adhesiveness and bonding property after UV irradiation can be improved further. Moreover, 50 mass % or less is preferable, and 45 mass % or less may be sufficient as the upper limit of content of the 1st (meth)acrylate component in an adhesive composition, and 42 mass % or less may be sufficient as it. By setting the amount of the first (meth)acrylate component in the adhesive composition to be 50% by mass or less, the elastic modulus after curing can be suppressed from becoming too high, and the adherends can be well bonded to each other, In addition, the amount of other components (eg epoxy resin) in the adhesive composition does not become too small, the delayed hardening property is more effectively exhibited, and higher adhesive strength can be obtained. Furthermore, when the adhesive composition contains two or more first (meth)acrylate components, it is preferable that the total amount of the first (meth)acrylate components satisfy the above numerical range.

<2nd (meth)acrylate component> The second (meth)acrylate component is a hydroxyl group-containing (meth)acrylate. The hydroxyl group-containing (meth)acrylate may have one or more hydroxyl groups in one molecule, or may have two or more hydroxyl groups in one molecule. The 2nd (meth)acrylate component may be used individually by 1 type, and may use 2 or more types together.

Specific examples of hydroxyl group-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, etc. Among them, 4-hydroxybutyl (meth)acrylate is preferable, and 4-hydroxybutyl acrylate is more preferable from the viewpoint of more effectively expressing the adhesiveness and retarded hardening property of the adhesive composition after UV irradiation. -Hydroxybutyl ester.

The content of the second (meth)acrylate component in the adhesive composition is preferably 2% by mass or more, may be 5% by mass or more, may be 10% by mass or more, may be 15% by mass or more, or may be 20% by mass or more. By setting the content of the second (meth)acrylate component in the adhesive composition to 2% by mass or more, the adhesiveness and delayed hardening can be more effectively expressed, and the retention of the coating shape and the adhesion can be further improved. strength. Moreover, 30 mass % or less is preferable, and 25 mass % or less may be sufficient as the upper limit of content of the 2nd (meth)acrylate component in an adhesive composition, and 22 mass % or less may be sufficient as it. By setting the content of the second (meth)acrylate component in the adhesive composition to 30% by mass or less, the amount of other components (eg epoxy resin) in the adhesive composition will not become too small relatively, Therefore, delayed hardenability is more effectively exhibited, and higher bonding strength can be obtained. Furthermore, when the adhesive composition contains two or more second (meth)acrylate components, it is preferable that the total amount of the second (meth)acrylate components satisfies the above numerical range.

<Radical Photopolymerization Initiator> A radical photopolymerization initiator is a polymerization initiator for the said 1st (meth)acrylate component and a 2nd (meth)acrylate component. As the radical photopolymerization initiator, for example, an α-hydroxyalkylphenone-based radical photopolymerization initiator or a benzophenone methyl ketal-based radical photopolymerization initiator can be used. As α-hydroxyalkylphenone-based radical photopolymerization initiators, for example, 1-hydroxycyclohexyl phenyl ketone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1 -Phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- {4-[4-(2-Hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methylpropan-1-one, oligo[2-hydroxy-2-methyl-[1 -(methyl vinyl) phenyl] acetone] etc. As a commercial item of the radical photopolymerization initiator, Irgacure 184 (1-hydroxycyclohexyl phenyl ketone, manufactured by BASF Corporation), Irgacure 1173 (2-hydroxy-2-methyl-1-phenyl ketone), Propan-1-one, manufactured by BASF Corporation), Irgacure 2959 (1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, BASF Company), Irgacure 127 (2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)-benzyl]phenyl}-2-methylpropan-1-one, BASF Corporation), Esacureone (oligo[2-hydroxy-2-methyl-[1-(methylvinyl)phenyl]acetone], manufactured by Lamberti Corporation) and the like. A radical photopolymerization initiator may be used individually by 1 type, and may use 2 or more types together.

Content of the radical photopolymerization initiator in an adhesive composition can be suitably selected according to the objective, For example, it may be 0.1 mass % or more, and 0.1-2.0 mass % may be sufficient as it.

<Cationic Photopolymerization Initiator> The cationic photopolymerization initiator is the above-mentioned polymerization initiator for epoxy resins. As the cationic photopolymerization initiator, onium salts such as diazonium salts, iodonium salts, and peronium salts can be used.

As the diazonium salt, for example, benzenediazonium hexafluoroantimonate, benzenediazonium hexafluorophosphate, benzenediazonium hexafluoroborate, etc. may be mentioned.

As the iodonium salt, for example, diphenyl iodonium tetrakis (pentafluorophenyl) borate, diphenyl iodonium hexafluorophosphate, diphenyl iodonium hexafluoroantimonate, bis(4-nonylphenyl) ) Idium hexafluorophosphate, bis(4-tert-butylphenyl) iodonium hexafluorophosphate, bis(4-tert-butylphenyl) iodonium hexafluoroantimonate, tolylcumyl iodonium tetra (Pentafluorophenyl)borate, (4-methylphenyl)[4-(2-methylpropyl)phenyl]idium hexafluorophosphate, and the like.

Examples of perylium salts include triaryl perylene hexafluorophosphate, triphenyl perylene hexafluorophosphate, triphenyl perylene hexafluoroantimonate, triphenyl perylene tetrakis(pentafluorophenyl) borate, Diphenyl[4-(phenylthio)phenyl]perylene hexafluoroantimonate, 4,4'-bis[diphenylperyl]diphenyl sulfide bishexafluorophosphate, 4,4'-bis [Bis(β-hydroxyethoxy)phenylperyl]diphenyl sulfide bishexafluoroantimonate, 4,4'-bis[bis(β-hydroxyethoxy)phenylperyl]diphenylsulfide Ether bis-hexafluorophosphate, 7-[di(p-toluyl) peryl]-2-isopropylthioxanthone hexafluoroantimonate (7-[di(p-toluyl)sulfonio]-2- isopropylthioxanthone hexafluoroantimonate), 7-[bis(p-toluyl) peryl]-2-isopropylthioxanthone tetrakis (pentafluorophenyl) borate, 4-phenylcarbonyl-4'-diphenyl peryl yl-diphenyl sulfide hexafluorophosphate, 4-(p-tert-butylphenylcarbonyl)-4'-diphenyl peryl-diphenyl sulfide hexafluoroantimonate, 4-(p-tert-butyl phenylcarbonyl) phenylcarbonyl)-4'-bis(p-tolylyl) peryl-diphenyl sulfide tetrakis (pentafluorophenyl) borate, etc.

From the viewpoint of the heat resistance (coloring resistance) after curing of the adhesive composition, the cationic photopolymerization initiator is preferably a cationic photopolymerization initiator whose anionic species is phosphorus-based. Specific examples of the phosphorus-based cationic photopolymerization initiator include Omnicat 250 (manufactured by IGM Resin), AT-6992 (manufactured by Pakistan Industries, Ltd.), and the like. A cationic photopolymerization initiator may be used individually by 1 type, and may use 2 or more types together.

The content of the cationic photopolymerization initiator in the adhesive composition may be appropriately selected according to the purpose, and may be, for example, 0.1% by mass or more, or 0.1 to 2.0% by mass.

As described above, the adhesive composition contains 45 to 70% by mass of the epoxy resin, the first (meth)acrylate component, the second (meth)acrylate component, the radical photopolymerization initiator, and the The cationic photopolymerization initiator can maintain the coating shape after UV irradiation even when an epoxy-cationic curing adhesive is used, and can provide good adhesion strength after curing.

Moreover, as another embodiment, the adhesive composition may contain more than 30 mass % and 70 mass % or less of the hydrogenated epoxy resin, the first (meth)acrylate component, the second (meth)acrylate component, Radical photopolymerization initiator and cationic photopolymerization initiator. Such an adhesive composition can also exhibit the effect of the said technique. By making the content of the hydrogenated epoxy resin in the adhesive composition more than 30% by mass, it is possible to express higher adhesive strength after UV irradiation. In addition, by making the content of the hydrogenated epoxy resin in the adhesive composition 70% by mass or less, other components (for example, the first (meth)acrylate component or the second (meth)acrylate component) are relatively becomes too small, and exhibits adhesion and shape retention after UV irradiation.

The adhesive composition may further contain other components other than the above-mentioned components within a range that does not impair the effect of the present technology. As other components, other (meth)acrylates other than the above-mentioned first (meth)acrylate component and second (meth)acrylate component, plasticizers, adhesion imparting agents, and sensitizers may, for example, be mentioned. Wait.

However, it is preferable that the adhesive composition does not substantially contain other (meth)acrylate components other than the first (meth)acrylate component and the second (meth)acrylate component described above. For example, in the adhesive composition, the content of other (meth)acrylate components other than the first (meth)acrylate component and the second (meth)acrylate component may be 10 mass % or less, or may be 5 mass % or less, and may be 1 mass % or less.

In order to achieve good inkjet compatibility under normal inkjet discharge conditions, the viscosity of the adhesive composition at 25°C is, for example, 5 mPa·s or more, preferably 10 mPa·s or more, more preferably 15 mPa·s above, and the viscosity at 60°C is 50 mPa·s or less, preferably 30 mPa·s or less, more preferably 20 mPa·s or less. If the viscosity of the adhesive composition at 25°C is less than 5 mPa·s, there is a tendency for droplets to be easily generated from the inkjet nozzle. In addition, when the viscosity of the adhesive composition at 60°C exceeds 50 mPa·s, there is a tendency that no ejection occurs. In addition, the viscosity of the adhesive composition at 25°C is preferably 50 mPa·s or less. Furthermore, the viscosity of the adhesive composition at 60°C is preferably 5 mPa·s or more. In addition, the viscosity of the adhesive composition in the range of 25 to 60°C is preferably 5 to 50 mPa·s. The viscosity of the adhesive composition can be determined by the method of the following examples.

＜Manufacturing method of bonded body＞ The manufacturing method of the bonded body using the adhesive composition of this technology has the following steps A, B and C. Hereinafter, as a specific example of the manufacturing method of a bonded body, it demonstrates in the order of 1st Embodiment and 2nd Embodiment.

[First Embodiment] <Step A> FIG. 2 is a perspective view for explaining an example of a method for producing a bonded body using an adhesive composition. In step A, as shown in FIG. 2(A) , the adhesive composition 2 of the present technology is applied to the first adherend 1 to form an adhesive composition layer 3 . When the adhesive composition 2 has the viscosity characteristics as described above, good inkjet adaptability can be achieved under normal inkjet ejection conditions. Therefore, in step A, the adhesive composition 2 can be applied using the inkjet head 4 . In addition, the coating method of the adhesive composition 2 is not limited to the inkjet method, and can be appropriately selected according to the purpose, for example, a jet dispense method, a spray method, a spin coating method, etc. may be used.

Specifically, in step A, the first adherend 1 is prepared, and as shown in FIG. 2(A), the adhesive composition 2 is applied to the surface of the first adherend 1 from the nozzle of the inkjet head 4, The adhesive composition layer 3 is formed. The thickness of the adhesive composition layer 3 can be appropriately set according to the surface state of the first adherend 1 or the second adherend 5 described below, the required physical properties of the adhesive cured layer 6 , and the like. The coating of the subsequent agent composition 2 can be performed multiple times to obtain the desired thickness. In addition, by making the adhesive composition 2 liquid under the ink-jet conditions, even when the surface shape of the first adherend 1 or the surface shape of the second adherend 5 is deformed, the deformation can be eliminated. .

The first adherend 1 may be a translucent member or a non-translucent member. In the example shown in FIG. 2, the 1st to-be-adhered body 1 uses the translucent member which can visually recognize the image formed in the image display member. As a member which has translucency, glass, an acrylic resin, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, etc. plate-shaped material and sheet-shaped material are mentioned, for example. These materials can be hard-coated on one or both sides, anti-reflection treatments, and the like. Physical properties such as thickness and elasticity of the first adherend 1 can be appropriately determined according to the purpose of use. In addition, the first adherend 1 also includes a known adhesive or a hardened resin layer of an adhesive composition of the present technology that integrates a position input element such as a touch panel with the above-mentioned plate-like material or sheet-like material. .

The shape of the first adherend 1 can be appropriately selected according to the purpose. The first adherend 1 may have a curved surface shape, or may have a flat surface. As the curved shape, for example, a concavely curved shape or a convexly curved shape, a paraboloid of revolution, a hyperbolic paraboloid, and other quadric shapes may be used, and a portion of the curved shape and the quadric shape may have a flat portion.

<Step B> In step B, as shown in FIG. 2(B) , the adhesive composition layer 3 is irradiated with ultraviolet rays 8 from the ultraviolet irradiation unit 7 to form the adhesive cured layer 6 . Specifically, from the side of the first adherend 1 , the adhesive composition layer 3 obtained in Step A is irradiated with ultraviolet rays 8 from the ultraviolet irradiation unit 7 to form the light-transmitting adhesive cured layer 6 . Furthermore, in step B, as shown in A in FIG. 1 , it is preferable to use the following irradiation conditions of ultraviolet 8: the elastic modulus of the adhesive composition layer 3 after irradiation with ultraviolet 8 is when the adhesive can be attached in step C below the modulus of elasticity. As an example, in step B, the cumulative light intensity of the ultraviolet rays 8 may be set in the range of 2000 to 8000 mJ/cm ² , or in the range of 4000 to 6000 mJ/cm ² .

When the step of irradiating the ultraviolet ray 8 is not performed after the step B, the higher the hardening rate of the adhesive hardening layer 6, the better, for example, it may be 90% or more. Here, the hardening rate of the adhesive hardening layer 6 is a numerical value defined by the following ratio (consumption ratio), which is the first (meth)acrylate component in the adhesive composition layer 3 after ultraviolet irradiation and the The amount of the (meth)acryloyl group contained in the second (meth)acrylate component is relative to the first (meth)acrylate component and the second (meth)acrylate component in the adhesive composition layer 3 before ultraviolet irradiation. The ratio of the amount of the (meth)acryloyl group present in the acrylate component. The larger the value of the hardening rate, the more the hardening progresses.

As the ultraviolet irradiation unit 7 , for example, a device having an LED whose emission peak wavelength is in the range of 360 to 430 nm (as an example, the emission wavelength is 365±5 nm) can be used.

<Step C> In step C, as shown in FIG. 2(C) , the second adherend 5 is arranged on the surface of the adhesive hardened layer 6 , and the first adherend 1 and the second adherend 5 are connected through the adhesive hardened layer 6 . engage. By step C, the laminated body 9 in which the 1st to-be-adhered body 1, the adhesive hardened layer 6, and the 2nd to-be-adhered body 5 are laminated|stacked in this order can be obtained.

In step C, the second adherend 2 is bonded to the first adherend 1 from the adhesive cured layer 6 side. Specifically, in step C, as shown in FIG. 2(D) , by performing at least one of autoclave treatment and heat treatment, the curing of the adhesive cured layer 6 can be further accelerated. When heat treatment is performed in step C, it can be performed at normal pressure and a temperature of 10-80°C. In step C, autoclave treatment and heat treatment can also be combined. For example, in step C, autoclave treatment can be performed under the conditions of a pressure of 0.2-0.6 MPa and a temperature of 25-80°C. In step C, autoclave treatment may be performed without heating. For example, in step C, the laminated body 9 may be pressurized under the conditions of a pressure of 0.2 to 0.6 MPa and a temperature of 10 to 30°C.

The second adherend 5 is, for example, an image display member such as a liquid crystal display panel, an organic EL display panel, a plasma display panel, and a touch panel. The touch panel is obtained by integrating a display element such as a liquid crystal display panel and a position input element such as a touch panel through a known adhesive or a hardened resin layer 6 . Furthermore, when the touch panel has been integrated with the first adherend 1 , the touch panel may not be used as the second adherend 5 . The shape of the 2nd to-be-adhered body 5 is the same as that of the 1st to-be-adhered body 1, and can be suitably selected according to the objective. The second adherend 5 may have a curved shape or a flat surface.

The manufacturing method of the laminated body of this technology may further comprise the step D of placing the adhesive hardening layer 6 between the step B and the step C. The manufacturing method of the bonded body of the present technology can further include such step D. Therefore, after the ultraviolet ray 8 is irradiated to the adhesive composition layer 3 in step B, it is not necessary to perform step C immediately. Therefore, it is not necessary to manufacture the bonded body without step D. Compared with the method, the degree of freedom of the manufacturing steps is greater. In step D, for example, in step B, the adhesive composition layer 3 can be placed in this state after the ultraviolet irradiation unit 7 is used to irradiate the adhesive composition layer 3 with ultraviolet rays 8 . In addition, in the case of using an extraction type (batch type) ultraviolet irradiation device as the ultraviolet irradiation unit 7, in step D, in step B, after the ultraviolet irradiation unit 7 is used to irradiate the adhesive composition layer 3 with ultraviolet rays 8, The first adherend 1 to which the adhesive composition layer 3 was applied was pulled out from the ultraviolet irradiation unit 7 and placed. In this way, in the manufacturing method of the bonded body of this technology, step D may be included regardless of the type of the ultraviolet irradiation unit 7 . The standing time in step D may be, for example, within 5 minutes.

[Second Embodiment] FIG. 3 is a perspective view for explaining another example of the manufacturing method of the bonded body using the adhesive composition 2. FIG. In the second embodiment, the case where the first adherend 1 and the second adherend 5 are members that do not have translucency can be exemplified.

In step A, as shown in FIG. 3(A) , using the inkjet head 4 , the adhesive composition 2 is partially coated on the first adherend 1 to form a plurality of rectangular adhesive composition layers 3 .

In step B, as shown in FIG. 3(B) , the plurality of adhesive composition layers 3 are irradiated with ultraviolet rays 8 from the ultraviolet irradiation unit 7 to form a plurality of rectangular adhesive cured layers 6 . Specifically, from the side of the first adherend 1 , the plurality of adhesive composition layers 3 obtained in step A are irradiated with ultraviolet rays 8 from the ultraviolet irradiation unit 7 to form the plurality of adhesive cured layers 6 . The irradiation conditions of ultraviolet rays may be the same as those of the first embodiment.

In step C, as shown in FIG. 3(C) , the second adherend 5 is arranged on the surfaces of the plurality of adhesive hardened layers 6 , and the first adherend 1 and the second adherend are adhered through the adhesive hardened layer 6 . Body 5 is engaged. In Step C, the first adherend 1 and the plurality of second adherends 5 can be joined via the adhesive hardened layer 6 by, for example, performing heat treatment. Conditions for the heat treatment may be the same as those in the first embodiment. By step C, the laminated body 10 in which the 1st to-be-adhered body 1, the adhesive hardened layer 6, and the 2nd to-be-adhered body 5 are laminated|stacked in this order can be obtained. In step C, as shown in FIG. 3(D) , the curing of the adhesive cured layer 6 can be further accelerated by performing heat treatment. Conditions for the heat treatment may be the same as those in the first embodiment. [Example]

Hereinafter, embodiments of the present technology will be described. Furthermore, the present technology is not limited to these embodiments.

The ingredients used in this example are as follows.

jER YX8000: Hydrogenated epoxy resin, manufactured by Mitsubishi Chemical Corporation EPICLON EXA-830CRP: Bisphenol F-type epoxy resin, manufactured by DIC Corporation Viscoat 160: Aromatic acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd. Viscoat 155: Alicyclic acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd. Viscoat 150: Heterocyclic acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd. LA: Aliphatic acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd. 4HBA: Hydroxy Acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd. Denacol EX-121: Monofunctional epoxy resin, manufactured by Nagase Chemical Co., Ltd. ARONOXETANE OXT-221: Multifunctional oxetane resin, manufactured by Toagosei Co., Ltd. PI-184: Radical photopolymerization initiator, manufactured by Hunan Company AT-6992: Phosphorus-based cationic photopolymerization initiator, manufactured by Pakistan Industries Omnicat 250: Phosphorus-based cationic photopolymerization initiator, manufactured by IGM Resin

[Viscosity] The adhesive composition was prepared by uniformly mixing the components shown in Table 1. The viscosity of the obtained adhesive composition at 25°C was measured using a rheometer (HaakeRheoSress600, Thermo Fisher Scientific; measurement conditions: conical rotor, ϕ=35 mm, rotor angle 2°, shear rate 120 1/s). The results are shown in Table 1. From the viewpoint of inkjet coating, the viscosity of the adhesive composition is preferably less than 50 mPa·s.

[Temporary Adhesion] An adhesive composition was prepared by uniformly mixing the components shown in Table 1. Prepare two glass slides (width 26 mm × length 76 mm × thickness 1.0-1.2 mm), and coat the center of one glass slide with an adhesive composition to form an adhesive composition layer. The adhesive composition layer was irradiated with light having a peak at a wavelength of 365 nm from a UV-LED at an intensity of 1000 mW/cm ² for 5 seconds, so that the cumulative light amount reached 5000 mJ/cm ² . Next, after placing another glass slide in a manner orthogonal to the above-mentioned one glass slide, heating at 60° C. for 10 minutes, a temporary adhesion test with an adhesive hardened layer with a thickness of about 0.2 mm can be obtained. with samples. Regarding the temporary adhesion of the sample, when the bonding between the glass slides was completed, in other words, there was no rebound after ultraviolet irradiation (the phenomenon that the temporarily bonded glass slides peeled off), the evaluation was OK, and the other cases were evaluated. for NG. The results are shown in Table 1.

[Permeability] Adhesive compositions were prepared by uniformly mixing the components shown in Table 1. Prepare two glass slides (width 40 mm × length 70 mm × thickness 0.4 mm), and coat the adhesive composition on the center of one glass slide to form the adhesive composition layer. The adhesive composition layer was irradiated with light having a peak at a wavelength of 365 nm from a UV-LED at an intensity of 1000 mW/cm ² for 5 seconds, so that the cumulative light amount reached 5000 mJ/cm ² . Next, after placing another glass slide on the above-mentioned one glass slide, it was heated at 60° C. for 10 minutes, thereby obtaining a light transmittance test sample having an adhesive hardened layer with a thickness of about 0.1 mm. The visible light transmittance of the sample was measured. Specifically, with respect to the adhesive cured layer of the sample for light transmittance test, the light transmittance in the wavelength range of 400 to 800 nm was measured, and the minimum value of the light transmittance was obtained. In the case of optical applications, the light transmittance of the adhesive hardened layer is preferably 90% or more. The results are shown in Table 1. In Table 1, for example, "OK (100)" in Example 1 indicates that the minimum value of the light transmittance in the wavelength range of 400 to 800 nm is 100%, and the evaluation is good. In addition, "NG (44)" of the comparative example 2 shows that the minimum value of the light transmittance in the wavelength range of 400-800 nm is 44%, and evaluation is not favorable.

[Heat resistance] The visible light transmittance was measured about the adhesive hardened layer after heating the said sample for transmittance|permeability test at 200 degreeC for 1 hour. Specifically, the light transmittance in the wavelength range of 400 to 800 nm was measured for the adhesive cured layer after the sample for transmittance test was further heated at 200° C. for 1 hour, and the minimum value of the light transmittance was obtained. In the case of optical applications, the light transmittance of the adhesive hardened layer is preferably 90% or more. The results are shown in Table 1.

[High temperature holding force] FIG. 4 is a perspective view for explaining the method of high temperature holding force test. The adhesive composition was prepared by uniformly mixing the components shown in Table 1. Two glass slides (width 26 mm × length 76 mm × thickness 1.0-1.2 mm) were prepared, and the adhesive composition was coated on one glass slide to form the adhesive composition layer. The adhesive composition layer was irradiated with light having a peak at a wavelength of 365 nm from a UV-LED at an intensity of 1000 mW/cm ² for 5 seconds, so that the cumulative light amount reached 5000 mJ/cm ² . Next, after placing another glass slide on one glass slide, it was heated at 60° C. for 10 minutes. Thereby, as shown in FIG. 4, the laminated body 9A whose adhesive area of the adhesive hardened layer 6 between slide glass 1A, 5A was 26 mm x 26 mm was obtained. Then, a load 11 of 1 kg was hung on the slide glass 5A, and a holding force tester (device name: BE-501, manufactured by TESTER SANGYO Co., Ltd.) was used to determine whether the slide glass 1A was shifted after being placed in an environment of 85°C for 1 hour. Evaluate. When the slide glass 5A was not shifted, it was evaluated as OK, and other cases were evaluated as NG. The results are shown in Table 1.

[Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Ingredient A jER YX8000 55 55 55 55 55 0 55 55 0 20 30 EPICLON EXA-830CRP 0 0 0 0 0 55 0 0 0 0 0 Ingredient B Viscoat 160 25 25 40 0 0 25 45 0 0 0 0 Viscoat 155 0 0 0 40 0 0 0 0 0 0 65 Viscoat 150 0 0 0 0 40 0 0 0 0 0 0 - LA 0 0 0 0 0 0 0 40 0 0 0 Ingredient C 4HBA 20 20 5 5 5 20 0 5 100 0 5 - Denacol EX-121 0 0 0 0 0 0 0 0 0 70 0 ARONOXETANE OXT-221 0 0 0 0 0 0 0 0 0 10 0 Ingredient D PI-184 1 1 1 1 1 1 1 1 1 0 1 Ingredient E AT-6992 1 0 1 1 1 1 1 1 0 1 1 Omnicat 250 0 1 0 0 0 0 0 0 0 0 0 Viscosity ( mPa s ) OK ( 30 ) OK ( 32 ) OK ( 23 ) OK ( 26 ) OK ( 26 ) OK ( 26 ) OK ( 20 ) OK ( 30 ) OK ( 10 ) OK ( 12 ) OK ( 8 ) Temporary stickiness OK OK OK OK OK OK OK OK OK NG (unhardened) NG (Bounce) Penetration rate ( % ) OK ( 100 ) OK ( 98 ) OK ( 100 ) OK ( 100 ) OK ( 97 ) OK ( 92 ) OK ( 91 ) NG ( 44 ) OK ( 99 ) NG (cannot be crafted) OK ( 99 ) Heat resistance ( % ) OK ( 99 ) OK ( 97 ) OK ( 99 ) OK ( 100 ) OK ( 99 ) OK ( 93 ) OK ( 98 ) NG ( 46 ) OK ( 96 ) NG (cannot be crafted) OK ( 99 ) high temperature retention OK OK OK OK OK OK NG NG NG NG (cannot be crafted) NG

It can be seen that Examples 1 to 6 used epoxy resins containing 45 to 70 mass %, the first (meth)acrylate component, the second (meth)acrylate component, the radical photopolymerization initiator, and the cationic light. An adhesive composition of a polymerization initiator, or a hydrogenated epoxy resin containing more than 30 mass % and 70 mass % or less, a first (meth)acrylate component, a second (meth)acrylate component, and a radical Adhesive composition of photopolymerization initiator and cationic photopolymerization initiator, so the results of temporary adhesion and high temperature retention are good. In this way, it can be seen that the adhesive compositions used in Examples 1 to 6 are as shown in FIG. 1 by including the first (meth)acrylate component, the second (meth)acrylate component and the radical photopolymerization initiator. As shown by the curve (iii), curing starts immediately after UV irradiation, so the coating shape after UV irradiation can be maintained. Moreover, since the adhesive composition used in Examples 1-6 contains an epoxy resin and a cationic photopolymerization initiator, it turns out that the retardation hardening property after UV irradiation is exhibited, and the adhesive strength after hardening is favorable. Moreover, it turns out that the penetration rate and heat resistance of the adhesive composition used in Examples 1-6 are also favorable.

Moreover, from the results of Example 1 and Example 6, it can be seen that the penetration rate and heat resistance of the adhesive composition using the hydrogenated epoxy resin as the epoxy resin are more favorable.

It turned out that, since the comparative example 1 used the adhesive composition which does not contain a 2nd (meth)acrylate component, the result of the high temperature retention force was not good.

It can be seen that in Comparative Example 2, since the adhesive composition not containing the first (meth)acrylate component was used, in addition to the result of the high temperature retention force, the penetration rate and the heat resistance were also poor.

It can be seen that in Comparative Example 3, since an adhesive composition containing no epoxy resin, a cationic photopolymerization initiator, and a first (meth)acrylate component was used, the result of high temperature retention was not good. The reason for this is considered to be that, in Comparative Example 3, for example, as shown by the curve (ii) in FIG. 1 , delayed curability was not exhibited after UV irradiation.

It can be seen that in Comparative Example 4, since the adhesive agent which does not contain the first (meth)acrylate component, the second (meth)acrylate component and the radical photopolymerization initiator and has an epoxy resin content of 45% by mass or less is used The composition has poor curability, and it is difficult to form an adhesive cured layer. The reason for this is considered to be that, in Comparative Example 4, for example, as shown by the curve (i) in FIG. 1 , curing did not start immediately after UV irradiation.

In Comparative Example 5, since the adhesive composition with an epoxy resin content of 45 mass % or less was used, in addition to the poor high temperature retention, rebound after ultraviolet irradiation, that is, peeling of the temporary joint occurred.

1: The first adherend 1A: Slides 2: Adhesive composition 3: Adhesive composition layer 4: Inkjet head 5: The second adherend 5A: Slides 6: Adhesive hardening layer 7: UV irradiation unit 8: Ultraviolet 9: Laminate 9A: Laminate 10: Laminate 11: Load A: Elastic modulus that can fit (Dahlquist standard) (i), (ii), (iii): Curves

[FIG. 1] It is a graph for explaining the change with respect to time of the elastic modulus of an adhesive composition. [ Fig. 2 ] It is a perspective view for explaining an example of a method of manufacturing a bonded body using an adhesive composition, (A) is a perspective view for explaining step A, (B) is a perspective view for explaining step B , (C) and (D) are oblique views used to illustrate step C. [ Fig. 3 ] It is a perspective view for explaining another example of the manufacturing method of a bonded body using an adhesive composition, (A) is a perspective view for explaining step A, (B) is a perspective view for explaining step B Figures, (C) and (D) are perspective views for explaining step C. [Fig. 4] is a perspective view for explaining the method of the high temperature holding force test.

A: Elastic modulus that can fit (Dahlquist standard)

(i), (ii), (iii): Curves

Claims (14)

An adhesive composition, which contains: 45-70 mass % epoxy resin; At least one first (meth)acrylate component selected from the group consisting of aromatic (meth)acrylates, alicyclic (meth)acrylates and heterocyclic (meth)acrylates; The second (meth)acrylate component composed of hydroxyl-containing (meth)acrylate; free radical photopolymerization initiators; and Cationic photopolymerization initiator. The adhesive composition according to claim 1, wherein the epoxy resin is a hydrogenated epoxy resin. The adhesive composition according to claim 1 or 2, wherein the anionic species of the cationic photopolymerization initiator is a phosphorus-based cationic photopolymerization initiator. The adhesive composition according to any one of claims 1 to 3, which contains 20 to 50% by mass of the first (meth)acrylate component, and The said 2nd (meth)acrylate component is contained in 2-30 mass %. The adhesive composition according to any one of claims 1 to 4, whose viscosity at 25°C is 50 mPa·s or less. An adhesive composition containing: more than 30 mass % and 70 mass % or less of hydrogenated epoxy resin; At least one first (meth)acrylate component selected from the group consisting of aromatic (meth)acrylates, alicyclic (meth)acrylates and heterocyclic (meth)acrylates; The second (meth)acrylate component composed of hydroxyl-containing (meth)acrylate; free radical photopolymerization initiators; and Cationic photopolymerization initiator. A manufacturing method of a bonded body, it has the following steps: Step A, coating the adhesive composition of any one of claims 1 to 6 on the first adherend to form an adhesive composition layer; Step B, irradiating the above-mentioned adhesive composition layer with ultraviolet rays to form an adhesive hardened layer; and In step C, a second adherend is arranged on the surface of the adhesive hardened layer, and the first adherend and the second adherend are joined via the adhesive hardened layer. The manufacturing method of the bonded body of Claim 7 which performs at least one of autoclave processing and heat processing in said step C. The method for producing a bonded body according to claim 8, wherein in the step C, the heat treatment is performed at a normal pressure and a temperature of 10 to 80°C. The method for producing a bonded body according to claim 8, wherein in the step C, the autoclave treatment is performed at a temperature of 10 to 30°C. The manufacturing method of the laminated body according to any one of claims 7 to 10, wherein between the above-mentioned step B and the above-mentioned step C, there is further a step D of placing the above-mentioned adhesive hardened layer. The manufacturing method of the bonded body of claim 11, wherein in the above-mentioned step D, after the ultraviolet-ray is irradiated in the above-mentioned step B, it is left to stand in this state. The manufacturing method of the laminated body of claim 11, wherein, in the above-mentioned step D, after the ultraviolet irradiation unit is used in the above-mentioned step B to irradiate the ultraviolet rays, it is extracted from the above-mentioned ultraviolet irradiation unit and left to stand. The method for producing a bonded body according to any one of claims 7 to 13, wherein, in the step A, the adhesive composition is applied using an inkjet head.

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