KR20190051829A - Substrate bonding method - Google Patents

Abstract

The present invention relates to a substrate bonding method capable of controlling the thickness of an adhesive layer and capable of adjusting and repairing the bonding position. The method of bonding a pair of first substrates and a pair of second substrates which oppose each other using an ultraviolet curable liquid silicone rubber adhesive. The substrate bonding method comprises: a process of applying the adhesive onto the first substrate; a process of irradiating the adhesive with ultraviolet rays to semi-cure the adhesive; a process of laminating and boning the second substrate through the adhesive layer after semi-curing; and a process of further curing the adhesive by irradiating ultraviolet rays.

Description

[0001] SUBSTRATE BONDING METHOD [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of bonding a substrate, and more particularly, to a method of bonding a double-layer substrate using an ultraviolet curable liquid silicone rubber adhesive.

As an image display device, an acrylic resin or an acrylic resin is used as an adhesive for bonding a substrate such as a liquid crystal module (LCM) or a flexible printed circuit board (FPC) to another substrate such as a touch panel, a cover glass, Epoxy-based resins, and silicone-based adhesives. By bonding with the curing type adhesive, there is no clearance, display recognition property and durability are improved, and visibility of sunlight and the like is suppressed. At present, acrylic or epoxy resin is used for these bonding materials, but silicone rubber adhesives which are particularly optically transparent and excellent in light resistance and heat resistance and have a low elastic modulus have attracted attention recently (Patent Documents 1 and 2) .

As the image display apparatus has been shifting from a small size to a large size display apparatus, a silicone rubber adhesive having a lower elastic modulus has been studied as an adhesive for bonding materials having different expansion ratios at the time of heat (at the time of heat), and further, A structure in which an adhesive, which is also a bonding material, is thickened so as to follow the thermal change between the other substrates has been studied. However, in order to obtain an adhesive layer having a predetermined thickness by using a heat-curing or ultraviolet-curable silicone rubber adhesive, an adhesive called a damper is applied to the outer periphery of the region to be adhered to the first substrate, After charging, the second substrate was bonded and heated or irradiated with ultraviolet rays to cure and bond. However, in this process, since the damming agent is indispensable and it is difficult to adjust the bonding position in the liquid phase before heating or irradiation with ultraviolet rays, and after the bonding of the second substrate, There is a problem that it can not be done.

Japanese Patent Application Laid-Open No. 2014-005354 Japanese Patent Application Laid-Open No. 2014-169412

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method of bonding a substrate capable of controlling the thickness of the adhesive layer and adjusting and restoring the bonding position.

In order to achieve the above object, the present invention provides a method for adhering a pair of opposed first and second substrates using an ultraviolet curable liquid silicone rubber adhesive, the method comprising: a step of applying the adhesive onto the first substrate; Curing the adhesive by irradiating ultraviolet rays to the adhesive, a bonding step of laminating the second substrate with the semi-cured adhesive layer, and a step of finally curing the adhesive by irradiating ultraviolet light .

With this method, the thickness of the adhesive layer can be controlled, and the bonding position can be adjusted and restored.

Further, as the ultraviolet curable liquid silicone rubber adhesive,

(A) a compound represented by the general formula (1):

(Wherein m is an integer of 0, 1 or 2, R ¹ is a hydrogen atom, a phenyl group or a halogenated phenyl group, R ² is a hydrogen atom or a methyl group, R ³ is a monovalent same or different, Z ¹ represents -R ⁴ -, -R ⁴ O-, or -R ⁴ (CH ₃ ) ₂ SiO- (wherein R ⁴ represents a divalent identical or different carbon atom A substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms, Z ² is an oxygen atom, or a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms, which may be the same or different, .)

At least two climbing having the structure represented by the molecular organopolysiloxane, and the organopolysiloxane units without having a SiO _4/2 and SiO _3/2 units relative to the total siloxane _{units, SiO 2/2, SiO 1} /2 units To 100 parts by mass of a straight chain organopolysiloxane composed of only < RTI ID = 0.0 >

(B) a photopolymerization initiator: 0.01 to 10 parts by mass

Based liquid organopolysiloxane composition containing an ultraviolet ray-curable liquid organopolysiloxane composition.

Such a composition can be suitably used as an ultraviolet curable liquid silicone rubber adhesive.

As the ultraviolet curable liquid silicone rubber adhesive,

(C) a compound represented by the general formula (2):

(Wherein m 'represents an integer of 0, 1 or 2, R ^1' represents a hydrogen atom, a phenyl group or a halogenated phenyl group, R ^{2 '} represents a hydrogen atom or a methyl group, and R ^3' represents a monovalent, Z ^{1 '} is -R ^4' -, -R ^{4 '} O-, or -R ^4' (CH ₃ ) ₂ SiO-, wherein R ^{4 '} is a substituted or unsubstituted hydrocarbon group of 2 to 10 A substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms which may be the same or different, Z ^{2 '} represents an oxygen atom, or a divalent hydrocarbon group having 1 to 10 carbon atoms, which may be the same or different, Or a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms.

An organopolysiloxane having at least one of a molecular structure represented by the branched merchant organopolysiloxane having SiO _4/2 and / or SiO _3/2 for an average of 1 to 50mol% units relative to the total siloxane units, the (A It is preferable to use an ultraviolet curable liquid organopolysiloxane composition containing 1 to 100 parts by mass relative to 100 parts by mass of the component

If such an adhesive containing the component (C) is used, the mechanical strength after curing becomes good.

As described above, the ultraviolet curable liquid silicone rubber adhesive used in the present invention can be adhered to an adherend by irradiating an appropriate amount of light without using a primer, a solvent or heat. At this time, since the adhesive used in the present invention is easy to control the semi-curing, it is possible to control the thickness of the adhesive layer, to secure the adhesive layer having a constant thickness by irradiating ultraviolet light immediately after the adhesive is applied to the first substrate At this point in time, it is possible to adjust and repair the bonding position, which is a problem, in that it is a semi-hardening state having adhesiveness. Further, the ultraviolet-curing silicone rubber adhesive used in the present invention can be completely bonded by bonding the second substrate and irradiating ultraviolet rays again in a semi-cured state having an adhesive property.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view of a planar tensile bond strength test in an embodiment of the present invention. Fig.

As described above, there has been a demand for development of a bonding method of a substrate capable of controlling the thickness of the adhesive layer and capable of adjusting and repairing the bonding position.

As a result of intensive studies on the above problems, the inventors of the present invention have found that it is possible to control the thickness of the adhesive layer and to adjust and repair the bonding position by bonding the substrates in a semi-cured state in which the adhesive layer has a tackiness Thereby completing the present invention.

That is, the present invention relates to a method for adhering a pair of opposed first and second substrates using an ultraviolet curing type liquid silicone rubber adhesive, the method comprising the steps of: applying the adhesive onto the first substrate to form an adhesive layer; A step of irradiating the adhesive layer with ultraviolet rays to semi-cure the adhesive layer, a bonding step of laminating the second substrate with the adhesive layer after the semi-curing, and a step of finally curing the adhesive layer by irradiating ultraviolet light to be.

Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

<Bonding method>

The present invention relates to a method of manufacturing a liquid crystal display device, which comprises a step of applying an ultraviolet curing type liquid silicone rubber adhesive onto a first substrate to form an adhesive layer, a step of irradiating ultraviolet rays to the adhesive layer to semi-cure the adhesive layer, And a step of finally curing the adhesive layer by irradiating ultraviolet rays.

The present invention can be applied to a liquid crystal display (LCD), an organic EL display (OLED), a plasma display (PDP), a flat panel display (FPD) such as a flexible display, or a touch panel type FPD, Layer substrate using an ultraviolet curable liquid silicone rubber adhesive for bonding a substrate such as a touch panel, a cover glass, a cover film, or an FPD to a substrate such as a module (LCM) or a flexible printed wiring board (FPC) Method.

Further, the bonding method of the present invention can be suitably used in manufacturing an image display apparatus, and is particularly preferable as a bonding method of an ultraviolet curing type liquid silicone rubber adhesive interposed between a liquid crystal module and a cover glass or a cover film.

[Process for forming an adhesive layer by applying an adhesive]

In the bonding method of the present invention, an ultraviolet curing type liquid silicone rubber adhesive described later is applied on the first substrate to form an adhesive layer.

This step is to uniformly apply an adhesive on the first substrate and the coating method is preferably carried out by a spray coating, a flow coating, a curtain coating, a screen coating, an inflow and a combination thereof, preferably from 10 to 3000 micrometers , More preferably 50 to 1000 micrometers, particularly preferably 100 to 800 micrometers, to form an adhesive layer. If the thickness is 10 micrometers or more, the unevenness of the surface of the substrate can be reliably absorbed. If the thickness is 3,000 micrometers or less, the cost of the ultraviolet-curable silicone rubber adhesive can be suppressed to a low level, which is economical.

Examples of the first substrate include a liquid crystal module and a flexible printed wiring board, a touch panel, a cover glass, a cover film, and a flat panel display.

(Ultraviolet curable liquid silicone rubber adhesive)

In the bonding method of the present invention, an ultraviolet curable liquid silicone rubber adhesive is used. The ultraviolet curable liquid silicone rubber adhesive used in the present invention is excellent in coatability with no solvent, easy control of semi-curing after irradiation with ultraviolet rays, and excellent in adhesive force after final curing.

As the ultraviolet curable liquid silicone rubber adhesive used in the present invention, it is preferable to use an ultraviolet curable polysiloxane composition containing the components described below. In the following description, the weight average molecular weight in terms of polystyrene is measured by gel permeation chromatography.

- Component (A)

As the component (A), a compound represented by the general formula (1):

(Wherein m is an integer of 0, 1 or 2, R ¹ is a hydrogen atom, a phenyl group or a halogenated phenyl group, R ² is a hydrogen atom or a methyl group, R ³ is a monovalent same or different, Z ¹ represents -R ⁴ -, -R ⁴ O-, or -R ⁴ (CH ₃ ) ₂ SiO- (wherein R ⁴ represents a divalent identical or different carbon atom A substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms, Z ² is an oxygen atom, or a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms, which may be the same or different, .)

Climb a structure represented by at least two in the molecule having organopolysiloxane, and the organopolysiloxane units without having a SiO _4/2 and SiO _3/2 units relative to the total siloxane units, SiO _2/2, SiO _1/2 units May be used as the organopolysiloxane.

In the general formula (1), the substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms which may have the same or different monovalent groups represented by R ³ usually has 1 to 10 carbon atoms, preferably 1 to 8 carbon atoms And specific examples thereof include a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, An alkyl group such as a nonyl group or a decyl group; Aryl groups such as a phenyl group, a tolyl group, a xylyl group, and a naphthyl group; Aralkyl groups such as benzyl group, phenylethyl group and phenylpropyl group; Hydrocarbon groups such as vinyl, allyl, propenyl, isopropenyl, butenyl, hexenyl, cyclohexenyl, and octenyl; A substituted hydrocarbon group in which a part or all of the hydrogen atoms of these hydrocarbon groups are substituted with a halogen atom such as fluorine, bromine, or chlorine, a cyano group or the like, such as a chloromethyl group, a chloropropyl group, a bromoethyl group, , And cyanoethyl group. In these substituted or unsubstituted hydrocarbon groups, some of the hydrocarbon chains include ether bonds (etheric oxygen atoms), amide bonds, and the like.

Examples of the divalent substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms represented by R ⁴ or Z ² include an alkylene group such as a methylene group, an ethylene group, and a trimethylene group, and the like. Some or all of the hydrogen atoms may be substituted with a halogen atom such as fluorine, bromine or chlorine, a cyano group or the like, and those containing an ether bond, an amide bond or the like in the hydrocarbon chain may also be included.

In the general formula (1), when Z ¹ is a divalent group represented by -R ⁴ -, Z ² is preferably an oxygen atom, and Z ¹ is -R ⁴ O- or -R ⁴ (CH ₃ ) ₂ SiO-, Z ² is preferably a divalent substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms which may be the same or different.

The structure represented by the general formula (1) is, in a preferred embodiment, represented by the following general formula (3):

(Wherein m, R ¹ , R ² , R ³ and R ⁴ are as defined above for the general formula (1).)

Lt; / RTI &gt; Specific examples of the general formula (3) include the following.

The organopolysiloxane of component (A) is exemplified below. These organopolysiloxanes may be used singly or in combination of two or more as component (A).

(In the formula, the arrangement of each siloxane unit in parentheses may be random or block.)

The viscosity of the component (A) preferably has a viscosity of 100 to 200,000 mPa 占 퐏 at 25 占 폚, and a preferable range thereof is 500 to 50,000 mPa 占 퐏, and a more preferable range thereof is 1,000 to 5,000 mPa 占 퐏. When the viscosity of the component (A) is larger than 100 mPa · s, the cured product obtained by irradiating the adhesive used in the present invention with ultraviolet rays is not too hard and can be suitably used for an image display device. Is less than 200,000 mPa · s, the workability is lowered.

- Component (B)

As the photopolymerization initiator of the component (B), any known photopolymerization initiator used for the photopolymerization of the acrylic functional group may be used. For example, dialkoxyacetophenones such as benzoin and substituted benzoin (e.g. alkyl ester substituted benzoin), Michler's ketone, 2,2-diethoxyacetophenone (" DEAP "), And substituted benzophenones, acetophenones and substituted acetophenones, xanthones and substituted xanthones, 2,2-acylphosphine oxides, and the like. Specific examples of preferred photopolymerization initiators include diethoxyacetophenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, diethoxycanthone, chloro-thioxanthone, azobisisobutyronitrile, N-methyl Diethanolamine benzophenone, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, and mixtures thereof. Examples of the visible ray initiation system include camphorquinone oxyester initiator and nonfluorene-carboxylic acid peroxyester. A particularly preferred photopolymerization initiator in the present invention is DEAP.

Photopolymerization initiators are commercially available and are available, for example, under the trade names IRGACURE and DAROCURE from Gusiba Specialty Chemicals. Specific examples thereof include IRGACURE 184 (1-hydroxycyclohexyl phenyl ketone), IRGACURE 907 (2-methyl-1- [4- (methylthio) phenyl] , IRGACURE 369 (2-benzyl-2-N, N-dimethylamino-1- (4-morpholinophenyl) -1-butanone), IRGACURE 500 (combination of 1-hydroxycyclohexyl phenyl ketone and benzophenone ), IRGACURE 651 (2,2-dimethoxy-2-phenylacetophenone), IRGACURE 1700 (bis (2,6-dimethoxybenzoyl-2,4,4-trimethylphenyl) phosphine oxide and 2-hydroxy- Methyl-1-phenyl-propan-1-one), IRGACURE 819 [bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide], DAROCURE 1173 (2-hydroxy- Phenyl-1-propane) and 4265 (a combination of 2,4,6-trimethylbenzoyldiphenyl-phosphineoxide and 2-hydroxy-2-methyl-1-phenyl- (blue) as the photopolymerization initiator, dl- camphorquinone and IRGACURE 784 (bis (η ⁵ -2,4- cyclopentadiene-1-yl) -bis [2,6-difluoro -3- (1H- pyrrole -1-yl) phenyl] titanium).

The blending amount of the photopolymerization initiator as the component (B) is usually from 0.01 to 10 parts by mass based on 100 parts by mass of the component (A), and particularly preferably from 0.1 to 5 parts by mass from the viewpoint of the desired reactivity and deep- .

The component (B) may be used alone or in combination of two or more. The photopolymerization initiator may be a polymer obtained by reacting initiators with each other. Such photopolymerization initiators are described in U.S. Patent Nos. 4,477,326 and 4,587,276.

Other free radical initiators such as peroxide initiators can be used in combination with component (B). In this case, the blending amount is preferably 0.1 to 5 parts by mass relative to 100 parts by mass of the component (A). By adding a peroxide initiator in combination, it is possible to cure the adhesive used in the present invention by heating the adhesive portion used in the present invention, which can not be directly irradiated with ultraviolet rays, to about 60 to 100 캜, if necessary.

- Component (C)

The organopolysiloxane of the component (C) is a compound represented by the general formula (2):

(Wherein m 'represents an integer of 0, 1 or 2, R ^1' represents a hydrogen atom, a phenyl group or a halogenated phenyl group, R ^{2 '} represents a hydrogen atom or a methyl group, and R ^3' represents a monovalent, Z ^{1 '} is -R ^4' -, -R ^{4 '} O-, or -R ^4' (CH ₃ ) ₂ SiO-, wherein R ^{4 '} is a substituted or unsubstituted hydrocarbon group of 2 to 10 A substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms which may be the same or different, Z ^{2 '} represents an oxygen atom, or a divalent hydrocarbon group having 1 to 10 carbon atoms, which may be the same or different, Or a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms.

An organopolysiloxane having at least one of a molecular structure, a branched organopolysiloxane merchants a SiO _4/2 and / or SiO _3/2 units relative to the total siloxane units of the average having from 1 to 50mol% as shown.

The component (C) is preferably in the range of 1 to 100 parts by mass based on 100 parts by mass of the component (A), based on the use of the component (A). When the component (C) is not less than 1 part by mass, the desired hardened product can be expected to be improved in mechanical strength. When the component (C) is not more than 100 parts by mass, the hardness of the obtained hardened product is not too hard, .

The organopolysiloxane of component (C) is exemplified below. These organopolysiloxanes may be used singly or in combination of two or more as component (C).

(c-1)

To MA units (SiO _1/2) and M units (SiO _1/2) and comprising a Q unit (SiO _4/2), and the molar ratio of these units MA: M: Q = 1: 4: 5 , and the polystyrene Based on the weight of the organopolysiloxane having a weight average molecular weight of 5,000.

· MA unit:

· M unit:

· Q unit:

(c-2)

And 7: to MA-D unit (SiO _2/2) and D units (SiO _2/2) and T units (SiO _3/2) includes, and a molar ratio of MA-D a: D: T = 2: 6 An organopolysiloxane having a weight average molecular weight of 3,500 in terms of polystyrene.

· MA-D Unit:

· D unit:

· T unit:

The viscosity of the component (C) is preferably 100 to 200,000 mPa 占 퐏 at 25 占 폚 like the component (A), more preferably 500 to 50,000 mPa 占 퐏, 10,000 mPa · s. When the viscosity of the component (C) is more than 100 mPa · s, the cured product obtained by irradiating the adhesive used in the present invention with ultraviolet rays is not too hard and can be suitably used for an image display device. Is less than 200,000 mPa · s, the workability is deteriorated.

- Other ingredients -

Other components may be incorporated into the adhesive used in the present invention, if necessary.

· Reactive diluent:

A reactive diluent not containing silicon may be added for the purpose of imparting durability such as viscosity of an adhesive and hardness of a cured product, durability against high temperature, in particular transparency after anti-wet heat treatment, and adhesion to a substrate.

As reactive diluents that do not include silicon, there are (meth) acrylates such as those represented by H ₂ C = CGCO ₂ Q where G is hydrogen, halogen, or alkyl having 1 to about 4 carbon atoms ; Q is selected from alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkaryl, aralkyl or aryl groups of from 1 to about 16 carbon atoms, any one of which may optionally be substituted with silane, , Carbonyl, hydroxyl, ester, carboxylic acid, urea, urethane, carbamate, amine, amide, sulfur, sulfonate, sulfone and the like.

More specific examples of the (meth) acrylates particularly preferable as the reactive diluent include bisphenol-A di (meth) acrylates such as polyethylene glycol di (meth) acrylate, ethoxylated bisphenol-A (meth) acrylate ("EBIPA" (Meth) acrylate, tetrahydrofuran (meth) acrylate and di (meth) acrylate, citronellyl acrylate and citronellyl methacrylate, hydroxypropyl (meth) acrylate, hexanediol di Acrylate ("HDDA" or "HDDMA"), trimethylolpropane tri (meth) acrylate, tetrahydrodicyclopentadienyl (meth) acrylate, ethoxylated trimethylolpropane triacrylate Ethylene glycol diacrylate and triethylene glycol dimethacrylate ("TRIEGMA"), dioxane glycol di (meth) acrylate (for example, manufactured by Nihon Kayaku KK, K Acrylate (for example, KAYARAD R-684, tricyclodecane dimethylol diacrylate, manufactured by Nihon Kayaku K.K.), acrylonitrile dimethacrylate (AYARAD R-604, dioxane glycol diacrylate) , And isobornyl acrylate and isobornyl methacrylate. Of course, these (meth) acrylates may be used alone or in combination of two or more as a reactive diluent.

When a reactive diluent is used, it may be added in an amount of 0.05 to 50 parts by weight based on 100 parts by weight of the component (A).

Modifier:

The adhesive used in the present invention is not particularly limited as long as it can be used in a specific application requiring adhesion to various substrates such as glass, acrylic, polycarbonate, and PET, Other ingredients may also be included to modify the properties. For example, an adhesion promoter such as (meth) acryloxypropyltrimethoxysilane, trialkyl- or triallyl-isocyanurate, glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane and the like may be contained in an amount of 5 mass% or less As shown in FIG.

In addition, non-(meth) acrylic silicone diluents or plasticizers can be added in amounts up to about 30 weight percent. Examples of the (meth) acryl-based silicone oils include trimethylsilyl end-use oils and silicone rubbers having a viscosity of 100 to 10,000 mPa 占 퐏 at 25 占 폚. The non-(meth) acrylsilicone series may include a copolymerizer such as a vinyl group for the purpose of introduction into the crosslinking of the adhesive used in the present invention.

· Inorganic filler:

An inorganic filler may be added to the adhesive. That is, silica such as fumed silica may be used, and it may be treated as it is as it is untreated (hydrophilic) and hydrophobic. Any fumed silica may be used alone or in combination of two or more.

When an inorganic filler is used, it may be blended in an amount of 0.1 to 20 parts by mass based on 100 parts by mass of the component (A).

The method for preparing the adhesive used in the present invention is preferably in the absence of ultraviolet rays. Specifically, an ultraviolet ray curable liquid silicone rubber adhesive can be obtained by mixing and mixing the components described above using a mixing stirrer equipped with a vacuum degassing apparatus.

[Step of irradiating ultraviolet rays to semi-cure the adhesive layer]

In the adhesion method of the present invention, an ultraviolet curing type liquid silicone rubber adhesive is applied on a first substrate to form an adhesive layer, and ultraviolet rays are irradiated to semi-cure the adhesive layer.

Examples of ultraviolet sources useful for semi-curing the adhesive layer include ordinary mercury vapor lamps and metal halide lamps designed to emit ultraviolet energy in various ultraviolet wavelength bands, for example, LED lamps emitting a specific single wavelength of only 365 nm .

For example, a useful ultraviolet wavelength range for semi-curing the adhesive layer is preferably 220 to 450 nm. Further, in order to make it semi-curing, the accumulated light quantity may be adjusted by the irradiation time.

[Bonding step of laminating the second substrate through the adhesive layer]

In the bonding method of the present invention, the second substrate is laminated and bonded to the first substrate through the semi-cured adhesive layer.

As a joining method, joining under vacuum using a vacuum joining apparatus can prevent mixing of bubbles, and a uniform bonding layer can be obtained. The vacuum bonding apparatus is a device for bonding an inorganic foil under a vacuum atmosphere, and a panel assembling apparatus generally used in a smart phone, a tablet PC, a touch panel, or the like can be used. The vacuum degree of vacuum of the vacuum bonding apparatus is 1000 Pas or less, preferably 100 Pas or less, and preferably 20 Pas or less.

As the second substrate used in the present invention, the same materials as those exemplified as the first substrate can be used.

[Step of curing the adhesive layer]

In the bonding method of the present invention, ultraviolet rays are irradiated on the laminated body of the first substrate and the second substrate bonded in the above to finally harden the semi-cured adhesive layer.

Examples of the ultraviolet light source useful for finally curing the semi-cured adhesive layer include the same ones as used for semi-curing the adhesive layer. Also in this case, in order to finally cure, the cumulative light quantity with the semi-curing can be adjusted by the irradiation time.

[Example]

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples, but the present invention is not limited thereto. The weight average molecular weight in terms of polystyrene is measured by gel permeation chromatography, and the viscosity is a value measured at 25 캜 using a rotational viscometer.

The ultraviolet irradiation conditions in the following examples and comparative examples were as follows.

UV irradiation conditions

The integrated amount of light was adjusted using an ultraviolet light illuminance of 100 mW / cm ² (365 nm) on the surface of the material by using an eye electronic control device manufactured by Iwasaki Denkai K.K.

Criteria for curing status

When the surface of the adhesive layer after irradiation with ultraviolet rays was contacted with a finger by the evaluation method in accordance with the tack free test test method of JIS K6249, the adhesive layer adhered to the finger was semi-cured. Further, the presence or absence of fluidity of the adhesive layer was determined.

Uncured: There is a sticky feeling and there is also fluidity.

Semi-hardening: There is a feeling of stickiness, but there is no fluidity.

Curing: No adhesive sensitivity or fluidity.

Flat tensile bond strength test

As shown in Fig. 1, glass plates 1 and 2 (first substrate and second substrate) each having a size of 25 mm x 100 m and a thickness of 2 mm were used and a glass plate 1 (first substrate) , An ultraviolet curing type liquid silicone rubber adhesive having an area not less than the adhesion area was applied to a thickness of about 500 mu m to form an adhesive layer 3 and irradiated with ultraviolet rays for a predetermined time. Further, another glass plate 2 (second substrate) was placed on the surface of the adhesive layer 3 after the irradiation, and finally, cured. As a method of measuring the adhesive strength, a glass plate bonded in a cross-shape was peeled up and down so as to be perpendicular to the adhesive surface, and the strength was measured.

(Examples 1 and 2 and Comparative Examples 1 and 2)

The following structural formula (4), 25 ℃ organopolysiloxane viscosity of 3,000mPa · s according to 100g and, 2,2-diethoxyacetophenone ( "DEAP") to 2g, as shown by MA units (SiO _{1 / 2)} and M units (SiO _1/2) and a Q unit (SiO _4/2) are included, and the molar ratio of these units a MA: M: Q = 1: 4: 5 , and the weight average molecular weight of 5,000 in terms of polystyrene , And 1 g of 3-methacryloxypropyltrimethoxysilane were uniformly mixed to prepare an ultraviolet curable liquid silicone rubber adhesive (Sample A).

(In the formula, the arrangement of each siloxane unit in parentheses may be random or block.)

· MA unit:

· M unit:

· Q unit:

A sample A was applied to the glass plate 1 to a thickness of about 500 mu m to form an adhesive layer 3, and ultraviolet rays of a predetermined cumulative light quantity were irradiated. Next, a separate glass plate 2 was bonded onto the adhesive layer 3 and irradiated with ultraviolet light having an accumulated light quantity of 24,000 mJ / cm ² . The plane tensile bond strength was measured. The results are shown in Table 1.

From the results shown in Table 1, it was found that the flat tensile bonding strength was good in Examples 1 and 2. Further, since the adhesive layer is semi-cured when bonding the substrates to each other, the bonding position can be adjusted and restored, and the thickness of the adhesive layer can also be controlled. On the other hand, in Comparative Example 1 in which the substrates were bonded to each other in the state that the adhesive layer was uncured, the thickness of the adhesive layer largely changed due to bonding, and the thickness of the adhesive layer could not be controlled, Could not be adjusted. Further, in Comparative Example 2 in which the substrates were bonded together in the cured state of the adhesive layer, that is, in the absence of the tackiness, the substrates were peeled off from each other.

From the above, it was confirmed that, in the bonding method of the present invention, the thickness of the adhesive layer can be controlled and the bonding position can be adjusted.

The present invention is not limited to the above-described embodiments. The above embodiment is an example, and anything that has substantially the same structure as the technical idea described in the claims of the present invention and exhibits the same operational effects is included in the technical scope of the present invention.

One… Glass plate (first substrate), 2 ... Glass plate (second substrate), 3 ... Adhesive layer.

Claims (3)

A method of bonding a pair of opposed first and second substrates using an ultraviolet curable liquid silicone rubber adhesive, the method comprising the steps of: applying the adhesive onto the first substrate to form an adhesive layer; A bonding step of laminating the second substrate through the semi-cured adhesive layer, and a step of finally curing the adhesive layer by irradiating ultraviolet light. The ultraviolet curable liquid silicone rubber adhesive according to claim 1,
(A) a compound represented by the general formula (1):

(Wherein m is an integer of 0, 1 or 2, R ¹ is a hydrogen atom, a phenyl group or a halogenated phenyl group, R ² is a hydrogen atom or a methyl group, R ³ is a monovalent same or different, Z ¹ represents -R ⁴ -, -R ⁴ O-, or -R ⁴ (CH ₃ ) ₂ SiO- (wherein R ⁴ represents a divalent identical or different carbon atom A substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms, Z ² is an oxygen atom, or a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms, which may be the same or different, .)
At least two climbing having the structure represented by the molecular organopolysiloxane, and the organopolysiloxane units without having a SiO _4/2 and SiO _3/2 units relative to the total siloxane _{units, SiO 2/2, SiO 1} /2 units To 100 parts by mass of a straight chain organopolysiloxane composed of only &lt; RTI ID = 0.0 &gt;
(B) a photopolymerization initiator: 0.01 to 10 parts by mass
Wherein the ultraviolet curing type liquid organopolysiloxane composition is used. The ultraviolet curable liquid silicone rubber adhesive according to claim 2,
(C) a compound represented by the general formula (2):

(Wherein m 'represents an integer of 0, 1 or 2, R ^1' represents a hydrogen atom, a phenyl group or a halogenated phenyl group, R ^{2 '} represents a hydrogen atom or a methyl group, and R ^3' represents a monovalent, Z ^{1 '} is -R ^4' -, -R ^{4 '} O-, or -R ^4' (CH ₃ ) ₂ SiO-, wherein R ^{4 '} is a substituted or unsubstituted hydrocarbon group of 2 to 10 A substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms which may be the same or different, Z ^{2 '} represents an oxygen atom, or a divalent hydrocarbon group having 1 to 10 carbon atoms, which may be the same or different, Or a substituted or unsubstituted hydrocarbon group having 1 to 10 carbon atoms.
An organopolysiloxane having at least one of a molecular structure represented by the branched merchant organopolysiloxane having SiO _4/2 and / or SiO _3/2 for an average of 1 to 50mol% units relative to the total siloxane units, the (A ) Component in an amount of 1 to 100 parts by mass based on 100 parts by mass of the ultraviolet curable liquid organopolysiloxane composition.

Images