JP2016190977A - Ultraviolet-curable liquid organopolysiloxane composition for image display device, adhesive for image display device containing the composition, image display device using the adhesive, and method for bonding using the adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultraviolet-curable liquid organopolysiloxane composition for an image display device which is capable of giving a cured product excellent in step followability.SOLUTION: The polysiloxane composition includes (A) 100 pts.mass of an organopolysiloxane having a mass ratio between the following (A-1) and (A-2), (A-1):(A-2), of 100:0-50:50, or a mixture thereof, (B) 0.01-10 pts.mass of photopolymerization initiator, and (C) 0.05-20 pts.mass of silica. (A-1) is a straight-chain organopolysiloxane having at least 2 structures represented by formula (1) in a molecule. (A-2) is a branched organopolysiloxane having at least 1 structure represented by formula (1) in a molecule.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an ultraviolet curable liquid organopolysiloxane composition for an image display device, an adhesive for an image display device containing the composition, an image display device using the adhesive, and a bonding method using the adhesive.

  A touch panel (also referred to as a touch screen panel) that is an optical display element is a combination of an image display unit such as a liquid crystal display device and an input unit that is a device that immediately recognizes and inputs coordinate axes. For example, the input unit is a laminate of a support plate (glass plate or resin plate) having a transparent conductive film (transparent conductive film) such as ITO (indium-tin oxide) and a cover panel (glass or resin). It is. The input unit is usually formed in place of a panel formed on the outermost surface on the display surface side of an FPD (flat panel display) such as a liquid crystal display or a CRT (CRT). A touch panel having an image display unit and an input unit can realize various operability by being combined with software.

  In addition, there are various types of touch panels, but two types, the resistive film type and the capacitive type, are the mainstream, and the capacitive type is further divided into a surface type capacitive type and a projected type capacitive type. The latter projection type applies an integration calculation method using XY grid drive electrodes, and there are a wire sensor method and a grid method. Furthermore, the grid method includes a self-capacitance detection method using one sensor and a mutual capacitance detection method using two transmission / reception sensors. Examples of methods other than the resistive film method and the capacitance method include an optical method, an ultrasonic method, an electromagnetic induction method, an in-cell method, and the like.

  The pressure-sensitive adhesive (adhesive sheet) used for the touch panel is in direct contact with the ITO surface, bonding of the outermost cover panel and the support plate having the ITO surface, and the support plate and the back surface (the image display unit side, In the case of a liquid crystal display, it can be used for bonding with a polarizing plate such as a TAC film. Further, a baseless double-sided pressure-sensitive adhesive sheet called “opti-carbonizing” is used when a support plate having an ITO surface and a liquid crystal display (polarizing plate) on the back side (backlight side) are bonded together. This pressure-sensitive adhesive sheet has different required physical properties from those used for bonding a cover panel and a support plate having an ITO surface.

  Conventionally, pressure-sensitive adhesives (also called pressure-sensitive adhesives) and pressure-sensitive adhesive sheets used in this application have problems with durability, particularly at high temperatures and high temperatures and high humidity. Occurrence, white turbidity and peeling of the adhesive layer in a high temperature and high humidity environment, and generation of fine bubbles were observed. In recent trends, a flat image display unit may be decorated by printing or the like in order to improve design. However, when the pressure-sensitive adhesive is bonded as it is to the step resulting from it, there is a problem such as entrainment of bubbles, and it is difficult to achieve both the former durability improvement and the latter step following ability.

  Patent document 1 is disclosing the adhesive which can suppress generation | occurrence | production of a bubble at the time of bonding of the transparent panel which has a flat image display part and a decoration part (step part). However, since the carboxyl group-containing monomer is used as an adhesive component, metal corrosion occurs when it comes into direct contact with the metal surface or metal thin film layer. It was difficult to use in the above.

  Furthermore, in the projection type capacitance method, etc., the acid component contained in the adhesive is a transparent conductive film such as ITO formed on a glass or resin sheet or film, or a circuit obtained by etching it. In addition, there is a problem that fine metal wiring such as silver, copper, and aluminum is corroded.

  Patent Document 2 discloses an adhesive composition that uses an alkoxy acrylate that does not contain a carboxyl group-containing monomer as a main monomer component and does not cause corrosion on a metal thin film layer. However, white turbidity of the pressure-sensitive adhesive layer occurs under high temperature and high humidity, and it cannot be said that the touch panel has sufficient performance as a pressure-sensitive adhesive for touch panels, and has not yet been sufficiently solved.

  Patent Document 3 discloses a transparent organosiloxane composition useful for a light-emitting diode (LED) device, but the cured product obtained by curing this composition by ultraviolet irradiation has a too hard rubber hardness. This composition is insufficient for an image display device.

JP 2009-155503 A JP 2009-79203 A Japanese Patent No. 5015571

  The present invention has been made in view of the above problems, and can provide a cured product having high transparency, excellent adhesion, excellent durability at high temperatures, and excellent step following ability, and curing. An object of the present invention is to provide an ultraviolet curable liquid organopolysiloxane composition for an image display device having a high shape-retaining property. Moreover, it aims at providing the adhesive agent for image display apparatuses containing this composition, the image display apparatus using this adhesive agent, and the adhesion | attachment method using this adhesive agent.

［式中、ｍは０、１又は２の整数、Ｒ^１は水素原子、フェニル基又はハロゲン化フェニル基、Ｒ^２は水素原子又はメチル基、Ｒ^３は１価の同一又は異なってもよい炭素原子数１〜１０の有機基、Ｚ^１は−Ｒ^４−、−Ｒ^４Ｏ−、又は、−Ｒ^４ＳｉＲ^３ _２Ｏ−（ここで、Ｒ^３は上記と同様であり、Ｒ^４は２価の同一又は異なってもよい炭素原子数１〜１０の有機基である）で表される２価の基、Ｚ^２は酸素原子、又は、２価の同一若しくは異なってもよい炭素原子数１〜１０の有機基である。］
（Ｂ）光重合開始剤：０．０１〜１０質量部、
（Ｃ）ＢＥＴ法により測定した比表面積が５０ｍ^２／ｇ以上であるシリカ：０．０５〜２０質量部、
を含有するものであることを特徴とする画像表示装置用紫外線硬化型液状オルガノポリシロキサン組成物を提供する。 In order to achieve the above object, in the present invention, (A) the following mass ratio (A-1) and (A-2) (A-1): (A-2) is 100: 0 to 50:50. Range of organopolysiloxanes or mixtures thereof: 100 parts by weight,
(A-1) A linear organopolysiloxane having at least two structures represented by the following general formula (1) in the molecule (A-2) A structure represented by the following general formula (1) in the molecule Branched organopolysiloxane having at least one

[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, and R ³ is a monovalent carbon which may be the same or different. 1 -C 10 organic group, ^{Z 1} is ^{-R 4 -, - R 4 O-} , ^or, -R ⁴ _SiR 3 2 O- (wherein, ^{R 3} are as defined above, ^{R 4} is 2 Z ² is an oxygen atom or a divalent carbon atom having 1 or the same or different carbon atom, which is an organic group having 1 to 10 carbon atoms which may be the same or different. -10 organic groups. ]
(B) Photopolymerization initiator: 0.01 to 10 parts by mass,
(C) Silica having a specific surface area measured by the BET method of 50 m ² / g or more: 0.05 to 20 parts by mass,
An ultraviolet curable liquid organopolysiloxane composition for an image display device is provided.

  Such a composition can provide a cured product having high transparency, excellent adhesion, excellent durability at high temperatures, and excellent step following property, and high shape retention before curing.

In the general formula (1), Z ¹ is preferably a divalent organic group represented by —R ⁴ —, and Z ² is preferably an oxygen atom.

In the general formula (1), Z ¹ is a divalent group represented by —R ⁴ O— or —R ⁴ SiR ³ ₂ O—, and Z ² may be the same or different from each other. An organic group having 1 to 10 carbon atoms is preferable.

  Such a composition is easily photocured.

  The present invention further provides an adhesive for an image display device comprising the ultraviolet curable liquid organopolysiloxane composition for an image display device of the present invention.

  With such an adhesive, an adhesive for bonding a panel and an image display unit in an FPD, an input unit and an image display unit in a touch panel, a cover panel and a support plate having a transparent conductive film in the input unit of the touch panel, etc. Can be suitably used.

  Furthermore, the present invention provides an image display device characterized in that a panel and an image display unit are bonded together using the adhesive for an image display device of the present invention.

  Further, in the present invention, at least one of a support plate having a transparent conductive film and an image display unit, and a cover panel and the support plate are bonded together using the image display device adhesive of the present invention. There is provided an image display device characterized by being.

  The composition of the present invention has high transparency, excellent adhesiveness, good durability at high temperatures, can give a cured product with excellent step followability, and has high shape retention before curing. Therefore, the image display apparatus using the adhesive containing the composition of the present invention has good durability at high temperatures.

  Further, in the present invention, using the adhesive for an image display device of the present invention, a panel and an image display unit, a support panel having a cover panel and a transparent conductive film, a support plate having an image display unit and a transparent conductive film, A bonding method characterized by bonding any of the above.

  With such an adhesion method, the bonding of any of the panel and the image display unit, the cover panel and the support plate having the transparent conductive film, and the image display unit and the support plate having the transparent conductive film is reliably achieved. can do.

  The composition of the present invention is excellent in coating property and shape retention before curing, and can give a cured product excellent in transparency, adhesiveness, durability, heat discoloration and step following property by ultraviolet curing. . In addition, the composition of the present invention does not corrode to a transparent conductive film such as ITO. That is, it has excellent corrosion resistance. In addition, when the composition of the present invention is used for adhesion of various substrates particularly in an FPD, a curved panel display, a touch panel, etc., display unevenness of the liquid crystal part hardly occurs even under high temperature and high humidity conditions. Therefore, the composition of the present invention is suitable for an image display device, for example, for an FPD, a curved panel display, a touch panel, and particularly for a capacitive touch panel. ), An adhesive material for various substrates such as glass, acrylic, polycarbonate, and PET.

  In particular, since the composition of the present invention can retain its shape before curing, it is useful as a dam material for preventing the liquid adhesive from flowing out when used in combination with a low-viscosity liquid adhesive.

It is a cross-sectional schematic diagram which shows an example of the touchscreen using the adhesive agent for image display apparatuses of this invention. It is a cross-sectional schematic diagram which shows an example of FPD using the adhesive agent for image display apparatuses of this invention.

  Hereinafter, the present invention will be described in more detail.

  As described above, the ultraviolet ray for an image display device has high transparency, excellent adhesion, excellent durability at high temperatures, can provide a cured product excellent in step following property, and has high shape retention before curing. There is a need for curable liquid organopolysiloxane compositions.

  The present inventors have intensively studied to achieve the above object. As a result, the inventors have found that an ultraviolet curable liquid organopolysiloxane composition for an image display device containing the following components (A) to (C) can solve the above problems, and has completed the present invention.

  Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited thereto. In the following description, the molecular weight is a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography.

［式中、ｍは０、１又は２の整数、Ｒ^１は水素原子、フェニル基又はハロゲン化フェニル基、Ｒ^２は水素原子又はメチル基、Ｒ^３は１価の同一又は異なってもよい炭素原子数１〜１０の有機基、Ｚ^１は−Ｒ^４−、−Ｒ^４Ｏ−、又は、−Ｒ^４ＳｉＲ^３ _２Ｏ−（ここで、Ｒ^３は上記と同様であり、Ｒ^４は２価の同一又は異なってもよい炭素原子数１〜１０の有機基である）で表される２価の基、Ｚ^２は酸素原子、又は、２価の同一若しくは異なってもよい炭素原子数１〜１０の有機基である。］
（Ｂ）光重合開始剤：０．０１〜１０質量部、
（Ｃ）ＢＥＴ法により測定した比表面積が５０ｍ^２／ｇ以上であるシリカ：０．０５〜２０質量部、
を含有するものである。 The ultraviolet curable liquid organopolysiloxane composition for an image display device of the present invention is:
(A) Organopolysiloxane having a mass ratio (A-1) :( A-2) of the following (A-1) and (A-2) of 100: 0 to 50:50 or a mixture thereof: 100 Parts by mass,
(A-1) A linear organopolysiloxane having at least two structures represented by the following general formula (1) in the molecule (A-2) A structure represented by the following general formula (1) in the molecule Branched organopolysiloxane having at least one

[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, and R ³ is a monovalent carbon which may be the same or different. 1 -C 10 organic group, ^{Z 1} is ^{-R 4 -, - R 4 O-} , ^or, -R ⁴ _SiR 3 2 O- (wherein, ^{R 3} are as defined above, ^{R 4} is 2 Z ² is an oxygen atom or a divalent carbon atom having 1 or the same or different carbon atom, which is an organic group having 1 to 10 carbon atoms which may be the same or different. -10 organic groups. ]
(B) Photopolymerization initiator: 0.01 to 10 parts by mass,
(C) Silica having a specific surface area measured by the BET method of 50 m ² / g or more: 0.05 to 20 parts by mass,
It contains.

  Such a composition can provide a cured product having high transparency, excellent adhesiveness, good durability at high temperatures, and excellent step following ability. Moreover, since it is liquid, it is excellent in workability. Furthermore, since the shape retention before curing is high, when used in combination with a low-viscosity liquid adhesive (for example, a liquid adhesive having a viscosity of 10,000 mPa · s or less), the liquid adhesive is prevented from flowing out. Useful as dam material.

-(A) component-
(A) component which comprises the composition of this invention is the range whose mass ratio (A-1) :( A-2) of following (A-1) and (A-2) is 100: 0-50: 50. Is an organopolysiloxane or a mixture thereof.

  In the present invention, the component (A-1) can be used alone as the component (A), but the component (A-1) and the component (A-2) are preferably used in combination as the component (A). By making the component (A) a mixture of the linear organopolysiloxane of the component (A-1) and the branched organopolysiloxane of the component (A-2), the composition of the present invention cures the composition. The cured product obtained in this way has an appropriate hardness. Such a composition can be more suitably used for an image display device.

（式中、ｍ、Ｒ^１、Ｒ^２、Ｒ^３、Ｚ^１、Ｚ^２は上記と同様である。）
で表される構造を分子中に少なくとも２つ有するオルガノポリシロキサンであって、ＳｉＯ_４／２単位及びＳｉＯ_３／２単位を有せず、ＳｉＯ_２／２とＳｉＯ_１／２単位のみで構成された直鎖状であるオルガノポリシロキサンが使用される。 As the component (A-1), the general formula (1):

(In the formula, m, R ¹ , R ² , R ³ , Z ¹ and Z ² are the same as above.)
An organopolysiloxane having at least two structures represented by the following _formula , having no SiO _4/2 units and SiO _3/2 units, and comprising only SiO _2/2 and SiO _1/2 units. A straight-chain organopolysiloxane is used.

In the general formula (1), the monovalent organic group having 1 to 10 carbon atoms represented by R ³ is specifically a methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert- Alkyl group such as butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, decyl group; aryl group such as phenyl group, tolyl group, xylyl group, naphthyl group; benzyl group, phenylethyl group Aralkyl groups such as phenylpropyl group; hydrocarbon groups such as alkenyl groups such as vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, hexenyl group, cyclohexenyl group, octenyl group; and the like of these hydrocarbon groups Substituted hydrocarbon groups in which part or all of the hydrogen atoms are substituted with halogen atoms such as fluorine, bromine, chlorine, cyano groups, etc. Examples thereof include halogen-substituted alkyl groups such as chloromethyl group, chloropropyl group, bromoethyl group, and trifluoropropyl group, cyanoethyl group, and the like, and in these substituted or unsubstituted hydrocarbon groups, a part of the hydrocarbon chain. Those containing an ether bond (etheric oxygen atom), an amide bond and the like are also included. In addition, the monovalent organic group represented by R ³ preferably has about 1 to 8 carbon atoms.

Examples of the divalent organic group having 1 to 10 carbon atoms represented by R ⁴ or Z ² include divalent substituted or unsubstituted hydrocarbon groups such as a methylene group, an ethylene group, and a trimethylene group. An alkylene group, etc., and some or all of the hydrogen atoms of these hydrocarbon groups may be substituted with halogen atoms such as fluorine, bromine and chlorine, cyano groups, etc., and further in these hydrocarbon chains Also included are those containing an ether bond, an amide bond and the like.

In the general formula (1), when Z ¹ is a divalent organic group represented by —R ⁴ —, Z ² is preferably an oxygen atom, and Z ¹ is —R ⁴ O— or When it is a divalent group represented by —R ⁴ SiR ³ ₂ O—, Z ² is preferably a divalent organic group having 1 to 10 carbon atoms which may be the same or different. Thereby, it will become a thing hardened | cured easily.

  Specific examples of the group having the structure represented by the general formula (1) include those represented by the following formula.

  Examples of the organopolysiloxane of component (A-1) are shown below. In these polysiloxanes, the arrangement of each siloxane repeating unit may be random or block. These organopolysiloxanes can be used alone or in combination of two or more as the component (A-1).

  (A-1) As a component, what has a viscosity of 100-200,000 mPa * s in 25 degreeC is suitable. A preferred range for the viscosity of the component (A-1) is 500 to 50,000 mPa · s, and a more preferred range is 1,000 to 5,000 mPa · s. When the viscosity of the component (A-1) exceeds 100 mPa · s, the cured product obtained by irradiating the composition of the present invention with ultraviolet rays does not become too hard and is suitable for an image display device. 1) When the viscosity of the component is less than 200,000 mPa · s, the workability is excellent.

  The molecular weight of the linear organopolysiloxane as the component (A-1) is not particularly limited, but the polystyrene-equivalent weight average molecular weight is preferably 2,000 to 100,000.

（式中、ｍ、Ｒ^１、Ｒ^２、Ｒ^３、Ｚ^１、Ｚ^２は上記と同様である。）
で表される構造を分子中に少なくとも１つ有するオルガノポリシロキサンであって、ＳｉＯ_４／２単位及び／又はＳｉＯ_３／２単位を含む分岐状オルガノポリシロキサンである。 The (A-2) component organopolysiloxane has the general formula (1):

(In the formula, m, R ¹ , R ² , R ³ , Z ¹ and Z ² are the same as above.)
And a branched organopolysiloxane containing at least one SiO _4/2 unit and / or SiO _3/2 unit.

Here, it is preferable to have 1 to 50 mol% of SiO _4/2 units and / or SiO _3/2 units with respect to the total of siloxane units of the component (A-2).

  The component (A-2) is used in a mass ratio of (A-1) :( A-2) of 100: 0 to 50:50, preferably on the premise of the use of the component (A-1). Is used in the range of 100: 0 to 60:40, more preferably 99: 1 to 60:40. If the amount of the component (A-2) exceeds 50%, the hardness of the resulting cured product becomes too hard, resulting in inferior adhesiveness and step following ability, and display unevenness when used as an adhesive for an image display device. It becomes a cause to cause the malfunction.

  Examples of the organopolysiloxane as component (A-2) are shown below. These organopolysiloxanes can be used alone or in combination of two or more as the component (A-2).

It consists of the following MA units (SiO _1/2 ), M units (SiO _1/2 ), and Q units (SiO _4/2 ), and the molar ratio of these units is MA: M: Q = 1: 4: 5. An organopolysiloxane having a polystyrene equivalent weight average molecular weight of 5,000

It consists of the following MA-D units (SiO _2/2 ), D units (SiO _2/2 ) and T units (SiO _3/2 ), and the molar ratio of these units is MA-D: D: T = 2: 6: 7 organopolysiloxane having a polystyrene-equivalent weight average molecular weight of 3,500

  As the component (A-2), a component having a viscosity of 100 to 200,000 mPa · s at 25 ° C. is suitable as in the case of the component (A-1). A preferred range for the viscosity of the component (A-2) is 500 to 50,000 mPa · s, and a more preferred range is 1,000 to 10,000 mPa · s. When the viscosity of the component (A-2) exceeds 100 mPa · s, the cured product obtained by irradiating the composition of the present invention with ultraviolet rays does not become too hard and is suitable for an image display device. 2) When the viscosity of the component is less than 200,000 mPa · s, the workability is excellent.

  The molecular weight of the branched organopolysiloxane as the component (A-2) is not particularly limited, but the polystyrene-equivalent weight average molecular weight is preferably 2,000 to 100,000.

  The refractive index (25 ° C.) of visible light (589 nm) of the component (A-1) and the component (A-2) is from 1.430 to 1 in view of compatibility (transparency) with the component (C) described later. A range of 470 is particularly suitable.

（式中、ｍ、Ｒ^１、Ｒ^２、Ｒ^３、Ｚ^１は上記と同様である。）
好ましくは下式に示す化合物、

（式中、ｍ、Ｒ^１、Ｒ^２、Ｒ^３、Ｚ^１、Ｚ^２は上記と同様である。）
より具体的には、例えば、１，３−ビス（３−メタクリロキシプロピル）テトラメチルジシロキサンと１，１，３，３−テトラメチルジシロキサンを酸触媒存在下で平衡化反応することによって得られる（３−メタクリロキシプロピル）−１，１，３，３−テトラメチルジシロキサンと、脂肪族不飽和基（例えば、エチレン性不飽和基、及びアセチレン性不飽和基が挙げられる。）を含むオルガノポリシロキサンとを、塩化白金酸触媒存在下でヒドロシリル化反応させるとよく、この方法で本発明に好適なものを製造することができるが、上記の合成方法に制限されるものではない。また、上記の脂肪族不飽和基を含むオルガノポリシロキサンは、脂肪族不飽和基を有するオルガノアルコキシシランを含むアルコキシシランの（共）加水分解縮合、酸触媒存在下での平衡化反応など公知の方法で製造することができ、市販のものを用いても良い。 As a synthesis method of such a component (A-1) and component (A-2), for example, organohydrogensilane shown below,

(In the formula, m, R ¹ , R ² , R ³ and Z ¹ are the same as above.)
Preferably, a compound represented by the following formula:

(In the formula, m, R ¹ , R ² , R ³ , Z ¹ and Z ² are the same as above.)
More specifically, for example, it can be obtained by equilibrating 1,3-bis (3-methacryloxypropyl) tetramethyldisiloxane and 1,1,3,3-tetramethyldisiloxane in the presence of an acid catalyst. (3-methacryloxypropyl) -1,1,3,3-tetramethyldisiloxane and an aliphatic unsaturated group (for example, an ethylenically unsaturated group and an acetylenically unsaturated group). The organopolysiloxane may be hydrosilylated in the presence of a chloroplatinic acid catalyst, and a method suitable for the present invention can be produced by this method, but the synthesis method is not limited to the above. In addition, the above-mentioned organopolysiloxane containing an aliphatic unsaturated group is known in the art such as (co) hydrolysis condensation of an alkoxysilane containing an organoalkoxysilane having an aliphatic unsaturated group, and an equilibration reaction in the presence of an acid catalyst. A commercially available product may be used.

-(B) component-
As the photopolymerization initiator of the component (B), any of those known as those used for photocuring acrylic functional groups can be used. For example, dialkoxyacetophenones such as benzoin and substituted benzoins (eg, alkyl ester substituted benzoins), Michael's ketone, 2,2-diethoxyacetophenone (“DEAP”), benzophenones and substituted benzophenones, acetophenones and substituted Examples include acetophenone, xanthone and substituted xanthone, and 2,2-acylphosphine oxide. Specific examples of desirable photopolymerization initiators include diethoxyacetophenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, diethoxyxanthone, chloro-thio-xanthone, azobisisobutyronitrile, N-methyldiethanolamine benzophenone, There are bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide and mixtures thereof. Visible light initiators can also be used, examples of which include camphoroquinone peroxyester initiators and non-fluorene-carboxylic acid peroxyesters. Of these, DEAP is particularly preferable.

Photopolymerization initiators can also be obtained commercially, for example, under the trade names IRGACURE and DAROCURE from BASF. Specifically, for example, IRGACURE 184 (1-hydroxycyclohexyl phenyl ketone), IRGACURE 907 (2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one), 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-2-methyl-1-phenyl-propan-1-one) Combination), IRGACURE 819 [bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide], DAROCURE1173 (2-hydroxy-2-methyl-1-phenyl-1-propane), and 4265 (2,4,6- A combination of trimethylbenzoyldiphenyl-phosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propan-1-one), and visible light (blue) photopolymerization initiators include dl-camforquinone and IRGACURE 784 ( Bis (η ⁵ -2,4-cyclopentadien-1-yl) -bis [2,6-difluoro-3- (1H-pyrrol-1-yl) phenyl] titanium).

  (B) The compounding quantity of the photoinitiator which is a component is 0.01-10 mass parts with respect to 100 mass parts of (A) component, From the surface of the reactivity desired by this invention, and a deep-part sclerosis | hardenability. Especially preferably, it is 0.1-5 mass parts. When the amount is less than 0.01 part by mass, the reaction may not proceed sufficiently. When it exceeds 10 mass parts, there exists a possibility that the hardened | cured material obtained may not have transparency, adhesiveness, durability in high temperature, and level | step difference followability. Moreover, there exists a possibility that the shape retainability before hardening of a composition may fall.

  Component (B) can 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 photoinitiators are described in US Pat. Nos. 4,477,326 and 4,587,276.

  Other free radical initiators such as peroxide initiators can also be used in combination with component (B). In this case, the blending amount is preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the component (A). By adding a peroxide initiator in combination, the composition of the present invention can be cured by heating at about 60 to 100 ° C. as necessary for the portion of the composition of the present invention that cannot be directly irradiated with ultraviolet rays. it can.

-(C) component-
(C) The silica of component is a component blended to maintain the shape of the applied composition of the present invention, as well as imparting strength to the cured product obtained by ultraviolet irradiation, and is a BET method (for example, The specific surface area measured by a nitrogen gas adsorption method is 50 m ² / g or more (usually 50 to 400 m ² / g). (C) The specific surface area of a component becomes like this. Preferably it is 100-350 m < ² > / g. When the specific surface area is less than 50 m ² / g, the ability to maintain the shape of the composition is inferior, which is not suitable. The BET method is a method in which gas molecules such as nitrogen and argon are adsorbed on solid particles, and the specific surface area of the solid particles is measured from the amount of adsorbed gas molecules.

  The silica may be hydrophilic or hydrophobic. As the hydrophilic silica, fine powder silica such as Aerosil 50, 130, 200, 300 (trade name, manufactured by Nippon Aerosil Co., Ltd.), Cabosil MS-5, MS-7 (trade name, manufactured by Cabot Corp.), Leorosil QS- 102, 103 (trade name, manufactured by Tokuyama Co., Ltd.), Nipsil LP (trade name, manufactured by Nippon Silica Co., Ltd.) and the like, and examples of hydrophobic silica include Aerosil R-812, R-812S, R-972. , R-974 (trade name, manufactured by Degussa), Leorosil MT-10 (trade name, manufactured by Tokuyama), Nipsil SS series (trade name, manufactured by Nippon Silica), and the like.

  The silica of component (C) can be used alone or in combination of two or more.

  In the case of using the above-mentioned hydrophilic fine powder silica, it is preferable to subject the surface to a hydrophobic treatment as necessary. Examples of the hydrophobizing agent include organosilazanes such as hexamethyldisilazane, halogenated silanes such as methyltrichlorosilane, dimethyldichlorosilane, and trimethylchlorosilane, and these halogen atoms are alkoxy groups such as methoxy group and ethoxy group. Examples include substituted organoalkoxysilanes. Examples of the hydrophobic treatment method include a method in which fine powder silica is heat-treated at 150 to 200 ° C., particularly 150 to 180 ° C. for about 2 to 4 hours together with the hydrophobic treatment agent. In addition, the surface treatment may be added to the composition of the present invention in advance, or in the step of preparing the composition of the present invention, the surface treatment may be performed by adding a hydrophobizing agent together with the component (A). It may be performed.

  The compounding quantity of (C) component to the composition of this invention needs to be the range of 0.05-20 mass parts with respect to 100 mass parts of said (A) component. If the blending amount of component (C) is less than 0.05 parts by mass, the effect of imparting thixotropy may be insufficient, and the shape of the applied composition may not be maintained. When the blending amount exceeds 20 parts by mass, the viscosity of the composition becomes too high, so that when the composition is applied, the workability is remarkably inferior.

-Other ingredients-
Other components can be blended in the composition of the present invention as necessary.

・ Reactive diluent:
Reactive diluents that do not contain silicone are used for the purpose of providing durability at high temperatures such as adjusting the viscosity of the composition and the hardness of the cured product, particularly transparency after wet heat treatment, and further imparting adhesiveness to the substrate. Can be added.

Silicone-free reactive diluents include (meth) acrylates as shown by H ₂ C═CGCO ₂ Q, where G is hydrogen, halogen, or 1 to about 4 carbon atoms. Q is selected from an alkyl group having 1 to about 16 carbon atoms, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an alkaryl group, an aralkyl group, or an aryl group, and any one of these is If necessary, it can be substituted or blocked with silane, silicon, oxygen, halogen, carbonyl, hydroxyl, ester, carboxylic acid, urea, urethane, carbamate, amine, amide, sulfur, sulfonate, sulfone and the like.

  More specific examples of (meth) acrylates that are particularly desirable as reactive diluents include polyethylene glycol di (meth) acrylate, ethoxylated bisphenol-A (meth) acrylate ("EBIPA" or "EBIPMA") Bisphenol-A di (meth) acrylate, tetrahydrofuran (meth) acrylate and di (meth) acrylate, citronellyl acrylate and citronellyl methacrylate, hydroxypropyl (meth) acrylate, hexanediol di (meth) acrylate ("HDDA" or "HDDMA "), Trimethylolpropane tri (meth) acrylate, tetrahydrodicyclopentadienyl (meth) acrylate, ethoxylated trimethylolpropane triacrylate (" ETTA ") , Triethylene glycol diacrylate and triethylene glycol dimethacrylate ("TRIEGMA"), dioxane glycol di (meth) acrylate (for example, KAYARAD R-604, dioxane glycol diacrylate, manufactured by Nippon Kayaku Co., Ltd.), tricyclodecanedi Examples include methylol di (meth) acrylate (for example, KAYARAD R-684, tricyclodecane dimethylol diacrylate, etc., manufactured by Nippon Kayaku Co., Ltd.), and isobornyl acrylate and isobornyl methacrylate. These (meth) acrylates can be used alone or as a reactive diluent in combination of two or more.

  In the case of using a reactive diluent, 0.05 to 50 parts by mass may be blended with respect to 100 parts by mass of component (A).

・ Modifier:
The composition of the present invention is resistant to discoloration at high temperatures and further modifies the desired cured or uncured properties in specific applications that require adhesion to various substrates such as glass, acrylic, polycarbonate, PET, etc. Other ingredients may also be included. For example, an adhesion promoter such as (meth) acryloxypropyltrimethoxysilane, trialkyl- or triallyl-isocyanurate, glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane and the like is included in an amount of 5% by mass or less. obtain.

  Non- (meth) acrylic silicone diluents or plasticizers can be added in amounts up to about 30% by weight. Non- (meth) acryl silicones are trimethylsilyl-terminated oil and silicone rubber having a viscosity of 100 to 10,000 mPa · s at 25 ° C. Non- (meth) acryl silicones may contain a copolymerizable group such as a vinyl group for the purpose of incorporation into the crosslinking of the composition of the present invention.

・ Inorganic filler:
You may add inorganic fillers other than (C) component to the composition of this invention. When using an inorganic filler, what is necessary is just to mix | blend 0.1-20 mass parts with respect to 100 mass parts of (A) component.

-Preparation and curing-
The method for preparing and curing the composition of the present invention is not particularly limited. Examples of the method for preparing the composition of the present invention include a method of using the above-mentioned components and mixing them together.

  The physical properties of the cured product obtained from the composition of the present invention depend on the molecular weight of the reactive silicone of the general formula (1), the curing method used, and the like. In general, the higher the molecular weight of the reactive silicone, the softer the cured reaction product is.

  Ultraviolet sources useful for curing the composition of the present invention include ordinary mercury vapor lamps and metal halide lamps designed to emit ultraviolet energy in various ultraviolet wavelength bands, and LED lamps emitting a single wavelength. Etc.

  The ultraviolet wavelength range for curing the composition of the present invention is desirably 220 to 450 nm.

  The composition of the present invention is formed directly or after being formed into a sheet shape, and then bonded to various base materials (for example, an image display unit) of a sheet and a film constituting a touch panel that is an optical display element, and irradiated with ultraviolet rays. It can be cured.

  Although the hardness of the hardened | cured material obtained by hardening | curing the composition of this invention is not specifically limited, The type A durometer hardness prescribed | regulated to JIS6249 becomes like this. Preferably it is 30 or less, More preferably, it is 10-30. If it is such hardness, it can be used more suitably for an image display device.

  The present invention further provides an adhesive for an image display device comprising the ultraviolet curable liquid organopolysiloxane composition for an image display device of the present invention. With such an adhesive, an adhesive for bonding a panel and an image display unit in an FPD, an input unit and an image display unit in a touch panel, a cover panel and a support plate having a transparent conductive film in the input unit of the touch panel, etc. Can be suitably used.

  Furthermore, the present invention provides an image display device in which a panel and an image display unit are bonded using the adhesive for an image display device of the present invention. In the present invention, the adhesive for an image display device of the present invention is used for at least one of a support plate having a transparent conductive film and an image display unit, and a cover panel and a support plate having a transparent conductive film. An image display device bonded together is provided. The composition of the present invention has high transparency, excellent adhesiveness, good durability at high temperatures, can give a cured product with excellent step followability, and has high shape retention before curing. Therefore, the image display apparatus using the adhesive containing the composition of the present invention has good durability at high temperatures.

  Here, examples of the image display device include a touch panel, an FPD, and a curved panel display. Moreover, a liquid crystal module can be mentioned as an image display part. The liquid crystal module may have a liquid crystal, a polarizing plate, and a TAC film. Examples of the material for the support plate include a glass plate and a resin plate. An example of the transparent conductive film is an ITO film. Moreover, glass, resin, etc. can be mentioned as a material of a panel and a cover panel.

  Hereinafter, an aspect of the image display device of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of a touch panel using the adhesive for an image display device of the present invention. As shown in FIG. 1, the touch panel 100 includes an input unit and an image display unit 2 each having a cover panel 1 and a support plate having a transparent conductive film. Here, the support plate having the transparent conductive film is obtained by forming the transparent conductive film 4 on the support plate 3. The surface of the cover panel 1 and the support plate 3 on which the transparent conductive film 4 is formed is bonded with the image display device adhesive 5 of the present invention. Further, the surface of the support plate 3 on which the transparent conductive film 4 is not formed and the image display unit 2 are bonded with the adhesive 5 of the present invention. In FIG. 1, an example in which the adhesive of the present invention is used for both adhesion of the cover panel 1 and the transparent conductive film 4 and adhesion of the support plate 3 and the image display unit 2 is shown. The adhesive of the present invention can also be used.

  FIG. 2 is a schematic cross-sectional view showing an example of an FPD using the adhesive for an image display device of the present invention. The FPD 200 includes a panel 11 and an image display unit 12. The panel 11 and the image display unit 12 are bonded with the image display device adhesive 5 of the present invention.

  Further, in the present invention, using the adhesive for an image display device of the present invention, a panel and an image display unit, a support panel having a cover panel and a transparent conductive film, a support plate having an image display unit and a transparent conductive film, An adhesion method for bonding any of the above is provided. With such an adhesion method, the bonding of any of the panel and the image display unit, the cover panel and the support plate having the transparent conductive film, and the image display unit and the support plate having the transparent conductive film is reliably achieved. can do.

  For example, when the FPD shown in FIG. 2 is manufactured, the adhesive 5 of the present invention is directly applied to the image display unit 12, the image display unit 12 and the panel 11 are bonded together, and then irradiated with ultraviolet rays to be cured. Thus, the image display unit 12 and the panel 11 can be bonded. Alternatively, the adhesive 5 of the present invention may be previously formed into a sheet shape, and the sheet thus obtained may be attached to the image display unit 12 or the panel 11.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited to the following Example.

[Examples 1-4, Comparative Examples 1-3]
Prepare the following (A-1) component, (A-2) component, (B) component, (C) component and a modifier component, and prepare a silicone composition having the composition shown in Table 1 (the numerical value is parts by mass). did. The resulting composition was measured for extension value by the following method to evaluate the shape stability of the composition before curing, and the results are shown in Table 2.

  Spreading value: A diameter (initial) after 10 seconds of applying 1.00 g of a silicone composition on a 50 mm square glass plate in a circular shape and a diameter after standing at 23 ° C. for 30 minutes were measured. In addition, when the value of the extension value (initial) was 40 mm or more, it was determined that there was no shape retainability.

The obtained composition was subjected to ultraviolet irradiation (500 mJ / cm ² ) with a high-pressure mercury lamp three times in a nitrogen atmosphere using a conveyor type UV irradiation device manufactured by Nippon Battery Co., Ltd. to obtain a cured product having a thickness of 2 mm. The hardness and transmittance of the cured product were evaluated by the following methods, and the results are shown in Table 2.

  Hardness: Measured with a durometer type OD manufactured by Shimadzu Corporation in accordance with the provisions of Durometer Shore OO Hardness Tester manufactured by Teclock Co., Ltd. and JIS 6249 in accordance with the provisions of ASTM D 2240.

  Light transmittance: About the light transmittance of the sample of the produced hardened | cured material, it measured with the wavelength of 400 nm using the spectrophotometer (Hitachi Ltd. U-3310), and made it the initial value. Next, the light transmittance after treatment for 1,000 hours was measured in a state where the sample was exposed in a dryer at 150 ° C.

  Moreover, about the obtained composition, the adhesiveness to glass was evaluated by the following method, and the result was shown in Table 2.

  Adhesiveness to glass: The composition of Examples and Comparative Examples was applied to a frame surrounded by a heat-resistant tape (thickness 80 μm) so that the application area was 20 mm × 25 mm on the glass plate, and another glass plate The composition was cured under the above-mentioned ultraviolet irradiation conditions with the composition sandwiched therebetween, and evaluated by ◯: adhesion, x: non-adhesion.

[(A-1) component]
Organopolysiloxane having a viscosity of 3,000 mPa · s at 25 ° C. and a refractive index (25 ° C.) at 589 nm of 1.446 represented by the following average molecular formula

[(A-2) component]
It consists of the following MA units (SiO _1/2 ), M units (SiO _1/2 ), and Q units (SiO _4/2 ), and the molar ratio of these units is MA: M: Q = 1: 4: 5. An organopolysiloxane having a polystyrene equivalent weight average molecular weight of 5,000

[(B) component]
2,2-diethoxyacetophenone (“DEAP”)

[Component (C)]
(C) -a Leoroseal DM-30 (manufactured by Tokuyama Corporation, specific surface area 300 m ² / g)
(C) -b AEROSIL (registered trademark) OX 50 (Evonik Industries AG, specific surface area 50 m ² / g)
(C) -c AEROSIL (registered trademark) RX 50 (Evonik Industries AG, specific surface area 35 m ² / g)
The specific surface areas of (C) -a to (C) -c are measured by the BET method.

[Modifier]
3-Methacryloxypropyltrimethoxysilane

  As shown in Table 2, the compositions of the present invention (compositions of Examples 1 to 4) have high shape retention before curing, and are cured with excellent transparency, heat resistance and adhesiveness by UV curing. It is suitable as an adhesive for an image display device. On the other hand, in Comparative Examples 1 and 2 in which the mass ratio of (A-1) :( A-2) is outside the range of 100: 0 to 50:50, the light transmittance after the heat treatment at 150 ° C. decreases. It did not show adhesion to glass.

The component (C) added to Examples 1 to 4 has a specific surface area of 50 m ² / g or more, whereas in Comparative Example 3 in which the component (C) having a specific surface area of 35 m ² / g was added, the extension value In the measurement, the sample flowed out, resulting in poor shape retention.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  The ultraviolet curable liquid organopolysiloxane composition for an image display device of the present invention is highly transparent and can give a cured product having excellent adhesion to a substrate. Since the composition of the present invention can retain its shape before curing, it is useful as a dam material for preventing the liquid adhesive from flowing out when used in combination with a low-viscosity liquid adhesive. Further, it has good durability at high temperatures, and is useful, for example, as a composition for FPDs, curved panel displays, particularly capacitive touch panels. Moreover, since it does not corrode with respect to transparent conductive films, such as ITO, and is soft and excellent in level | step difference followability, it can be used conveniently as an adhesive agent for image display apparatuses, a sealing agent, and an adhesive sheet.

DESCRIPTION OF SYMBOLS 1 ... Cover panel, 2, 12 ... Image display part, 3 ... Support plate,
4 ... Transparent conductive film, 5 ... Adhesive for image display device, 11 ... Panel,
100 ... Touch panel, 200 ... FPD.

Claims (7)

(A) Organopolysiloxane having a mass ratio (A-1) :( A-2) of the following (A-1) and (A-2) of 100: 0 to 50:50 or a mixture thereof: 100 Parts by mass,
(A-1) A linear organopolysiloxane having at least two structures represented by the following general formula (1) in the molecule (A-2) A structure represented by the following general formula (1) in the molecule Branched organopolysiloxane having at least one

[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, and R ³ is a monovalent carbon which may be the same or different. 1 -C 10 organic group, ^{Z 1} is ^{-R 4 -, - R 4 O-} , ^or, -R ⁴ _SiR 3 2 O- (wherein, ^{R 3} are as defined above, ^{R 4} is 2 Z ² is an oxygen atom or a divalent carbon atom having 1 or the same or different carbon atom, which is an organic group having 1 to 10 carbon atoms which may be the same or different. -10 organic groups. ]
(B) Photopolymerization initiator: 0.01 to 10 parts by mass,
(C) Silica having a specific surface area measured by the BET method of 50 m ² / g or more: 0.05 to 20 parts by mass,
An ultraviolet curable liquid organopolysiloxane composition for an image display device, comprising: 2. The ultraviolet ray for an image display device according to claim 1, wherein in the general formula (1), Z ¹ is a divalent organic group represented by —R ⁴ —, and Z ² is an oxygen atom. A curable liquid organopolysiloxane composition. In the general formula (1), Z ¹ is a divalent group represented by —R ⁴ O— or —R ⁴ SiR ³ ₂ O—, and Z ² is a divalent carbon atom that may be the same or different. The ultraviolet curable liquid organopolysiloxane composition for an image display device according to claim 1, wherein the composition is an organic group of formula 1 to 10.   The adhesive for image display apparatuses characterized by including the ultraviolet curable liquid organopolysiloxane composition for image display apparatuses of any one of Claims 1-3.   An image display device, wherein the panel and the image display unit are bonded together using the adhesive for an image display device according to claim 4.   A support plate having a transparent conductive film and an image display unit, and a cover panel and at least one of the support plate are bonded together using the adhesive for an image display device according to claim 4. A characteristic image display device.   Any one of a panel and an image display unit, a support panel having a cover panel and a transparent conductive film, and a support plate having an image display unit and a transparent conductive film using the adhesive for an image display device according to claim 4. A bonding method characterized by adhering together.

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