JPWO2015159957A1 - Transparent surface material with adhesive layer, display device, manufacturing method thereof, and adhesive sheet - Google Patents

Abstract

Display device with a display panel protected by a transparent surface material with a pressure-sensitive adhesive layer and a transparent surface material in which bubbles remaining at the interface between the material to be bonded and the pressure-sensitive adhesive layer can quickly disappear when bonded to the material to be bonded The manufacturing method and the pressure-sensitive adhesive sheet are provided. It has a transparent face material 10 and an adhesive layer 14 made of a cured product of a curable resin composition, formed on at least one surface of the transparent face material 10, and the concentration of hydroxyl groups in the adhesive layer 14 is 100 × 10 6. The transparent surface material 1 with the adhesion layer which is -6-600x10-6 mol / g and the density | concentration of the urethane bond in the adhesion layer 14 is 0-150x10-6 mol / g.

Description

  The present invention relates to a transparent surface material with an adhesive layer, a display device in which a display panel is protected by the transparent surface material, a manufacturing method thereof, and an adhesive sheet.

As a display device in which a display panel is protected by a transparent surface material, for example, the following is known.
(1) The display apparatus which bonded the display panel and the transparent surface material through the adhesive sheet (refer patent document 1, 2).
(2) The display apparatus which bonded the display panel and the transparent surface material with the adhesion layer so that the adhesion layer might contact the display panel (refer patent documents 3-5).

When manufacturing the display device of (1), the display panel is used in a reduced-pressure atmosphere so that no bubbles (voids) remain at the interface between the display panel and the adhesive sheet and at the interface between the transparent surface material and the adhesive sheet. And a transparent surface material are pasted together via an adhesive sheet, and then a method of returning it to an atmospheric pressure atmosphere is employed.
When the display device of (2) is manufactured, the display panel and the transparent surface material with the adhesive layer are placed under a reduced pressure atmosphere so that bubbles (voids) do not remain at the interface between the display panel and the adhesive layer. Then, after bonding so that the adhesive layer is in contact with the display panel, a method of returning it to the atmospheric pressure atmosphere is employed.

According to these methods, even if bubbles remain at the interface, the pressure in the bubbles (that is, the pressure in the reduced pressure state) is reduced by returning the display device in the reduced pressure atmosphere to the atmospheric pressure atmosphere. The volume of the bubbles decreases due to the pressure difference between the pressure applied to the pressure-sensitive adhesive sheet and the pressure-sensitive adhesive layer (ie, atmospheric pressure), and the bubbles disappear.
However, when a conventional pressure-sensitive adhesive sheet or a transparent surface material with a pressure-sensitive adhesive layer is used, it may take time for the bubbles remaining at the interface to disappear. If it takes time for the bubbles remaining at the interface to disappear, the productivity of the display device is lowered.

JP 2006-290960 A JP 2009-263502 A International Publication No. 2011/148990 International Publication No. 2012/077726 International Publication No. 2012/0777727

  The present invention provides a transparent surface with an adhesive layer in which bubbles remaining at the interface between the object to be bonded and the adhesive layer can quickly disappear when the object to be bonded and the transparent surface material are bonded via the adhesive layer. Material: A transparent surface material with a pressure-sensitive adhesive layer in which bubbles remaining at the interface between the material to be bonded and the pressure-sensitive adhesive layer can quickly disappear when the material to be bonded and the transparent surface material are bonded via the pressure-sensitive adhesive layer. Method for manufacturing; display device in which bubbles remain at the interface between the display panel and the adhesive layer; method for manufacturing a display device in which bubbles remain at the interface between the display panel and the adhesive layer are suppressed with high productivity And providing a pressure-sensitive adhesive sheet in which bubbles remaining at the interface between the material to be bonded and the pressure-sensitive adhesive sheet can rapidly disappear when bonded to the material to be bonded.

  As a result of intensive studies on the relationship between the characteristics of the adhesive layer and the disappearance rate of bubbles remaining at the interface between the object to be bonded and the adhesive layer, the inventors have determined the concentration of hydroxyl groups and the concentration of urethane bonds in the adhesive layer. It has been found that it takes time for bubbles to disappear when there are many.

The transparent surface material with an adhesive layer of the present invention has a transparent surface material and an adhesive layer made of a cured product of a curable resin composition, formed on at least one surface of the transparent surface material, and the adhesive layer The concentration of hydroxyl groups therein is 100 × 10 ⁻⁶ to 600 × 10 ⁻⁶ mol / g, and the concentration of urethane bonds in the adhesive layer is 0 to 150 × 10 ⁻⁶ mol / g.
The total of the hydroxyl group concentration in the adhesive layer and the urethane bond concentration in the adhesive layer is preferably 100 × 10 ^{−6 to} 750 × 10 ⁻⁶ mol / g.
The solubility parameter of the adhesive layer is preferably 17.5 to 18.5 (J / cm ³ ) ^1/2 .

The curable resin composition comprises a curable oligomer (A) having an addition polymerizable unsaturated double bond and a low molecular weight polymerizable compound (B) having an addition polymerizable unsaturated double bond, and the curing Either or both of the functional oligomer (A) and the low molecular weight polymerizable compound (B) preferably have a hydroxyl group. Either one or both of the curable oligomer (A) and the low molecular weight polymerizable compound (B) may have a urethane bond.
The curable resin composition comprises a curable oligomer (A) having an addition polymerizable unsaturated double bond, a low molecular weight polymerizable compound (B) having an addition polymerizable unsaturated double bond, and an addition polymerizable non-polymerizable compound. A non-curable oligomer (C) having no saturated double bond, and at least one of the curable oligomer (A), the low molecular weight polymerizable compound (B) and the non-curable oligomer (C), It preferably has a hydroxyl group. At least one of the curable oligomer (A), the low molecular weight polymerizable compound (B), and the non-curable oligomer (C) may have a urethane bond.
It is preferable that the transparent surface material with an adhesive layer of the present invention further has a peelable protective film that covers the surface of the adhesive layer.

The manufacturing method of the transparent surface material with the adhesion layer of this invention is a method of manufacturing the transparent surface material with the adhesion layer of this invention, Comprising: It has the following process ((alpha)) and the following process ((gamma)).
(Α) A step of supplying the liquid curable resin composition to the surface of the transparent surface material and partially curing the curable resin composition as necessary to obtain a partially cured product.
(Γ) A step of curing the curable resin composition or the partially cured product to form the adhesive layer.
It is preferable that the manufacturing method of the transparent surface material with the adhesion layer of this invention further has the following process ((beta)).
(Β) A step of covering the surface of the curable resin composition or the partially cured product with a protective film.

The step (α) is preferably the following step (α1), the step (β) is the following step (β1), and the step (γ) is preferably the following step (γ1).
(Α1) The liquid curable resin composition is supplied in a layer form on the surface of the transparent face material, and the curable resin composition supplied on the surface of the transparent face material is partially cured to be partially cured. Forming a layer.
(Β1) A step of covering the surface of the partially cured product layer with a protective film.
(Γ1) A step of further curing the partially cured product layer to form the adhesive layer.

The step (α) is the following step (α21) and the following step (α22), the step (β) is the following step (β2), and the step (γ) is the following step (γ21). And the following step (γ22) is preferred.
(Α21) A step of forming a frame-like weir at the peripheral edge of the surface of the transparent face material.
(Α22) A step of supplying the curable resin composition to a region surrounded by the weir.
(Β2) Under a reduced-pressure atmosphere, the support surface material with a protective film is stacked on the curable resin composition layer so that the protective film is in contact with the surface of the curable resin composition layer, The process of obtaining the laminated body by which the layer of the said curable resin composition was sealed with the said transparent surface material, the said protective film, and the said dam.
(Γ21) A step of forming the adhesive layer by curing the layer of the curable resin composition in a state where the laminate is placed under a higher pressure atmosphere than in the step (β2).
(Γ22) A step of peeling the support surface material from the protective film after the step (γ21).

The display apparatus of this invention has a display panel and the transparent surface material with the adhesion layer of this invention bonded by the said display panel so that the said adhesion layer may contact | connect the said display panel.
The display device manufacturing method of the present invention is a method of manufacturing the display device of the present invention, wherein the display panel and the transparent surface material with the adhesive layer are disposed in a reduced pressure atmosphere, and the adhesive layer is the display panel. Laminate and touch to touch.

The pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet made of a cured product of a curable resin composition, and the concentration of the hydroxyl group in the pressure-sensitive adhesive sheet is 100 × 10 ⁻⁶ to 600 × 10 ⁻⁶ mol / g, The density | concentration of the urethane bond in an adhesive sheet is 0-150 * 10 < ^-6 > mol / g.
The total of the hydroxyl group concentration in the pressure-sensitive adhesive sheet and the urethane bond concentration in the pressure-sensitive adhesive sheet is preferably 100 × 10 ^{−6 to} 750 × 10 ⁻⁶ mol / g.
The solubility parameter of the cured product of the curable resin composition is preferably 17.5 to 18.5 (J / cm ³ ) ^1/2 .

The curable resin composition comprises a curable oligomer (A) having an addition polymerizable unsaturated double bond and a low molecular weight polymerizable compound (B) having an addition polymerizable unsaturated double bond, and the curing Either or both of the functional oligomer (A) and the low molecular weight polymerizable compound (B) preferably have a hydroxyl group. Either one or both of the curable oligomer (A) and the low molecular weight polymerizable compound (B) may have a urethane bond.
The curable resin composition comprises a curable oligomer (A) having an addition polymerizable unsaturated double bond, a low molecular weight polymerizable compound (B) having an addition polymerizable unsaturated double bond, and an addition polymerizable non-polymerizable compound. A non-curable oligomer (C) having no saturated double bond, and at least one of the curable oligomer (A), the low molecular weight polymerizable compound (B) and the non-curable oligomer (C), It preferably has a hydroxyl group. At least one of the curable oligomer (A), the low molecular weight polymerizable compound (B), and the non-curable oligomer (C) may have a urethane bond.
The pressure-sensitive adhesive sheet with a protective film of the present invention has the pressure-sensitive adhesive sheet of the present invention and a peelable protective film that covers at least one surface of the pressure-sensitive adhesive sheet.

According to the transparent surface material with an adhesive layer of the present invention, when the object to be bonded and the transparent surface material are bonded via the adhesive layer, bubbles remaining at the interface between the object to be bonded and the adhesive layer are rapidly generated. Can disappear.
According to the method for producing a transparent surface material with an adhesive layer of the present invention, the object to be bonded and the transparent surface material are bonded to each other through the adhesive layer, and remain at the interface between the object to be bonded and the adhesive layer. It is possible to produce a transparent surface material with an adhesive layer in which bubbles can disappear quickly.
In the display device of the present invention, bubbles remain at the interface between the display panel and the adhesive layer.
According to the method for manufacturing a display device of the present invention, it is possible to manufacture a display device in which bubbles are prevented from remaining at the interface between the display panel and the adhesive layer with high productivity.
According to the pressure-sensitive adhesive sheet of the present invention, when the pressure-sensitive adhesive sheet is bonded to the object to be bonded, bubbles remaining at the interface between the object to be bonded and the pressure-sensitive adhesive sheet can quickly disappear.

It is sectional drawing which shows 1st Embodiment of the transparent surface material with the adhesion layer of this invention. It is sectional drawing which shows 2nd Embodiment of the transparent surface material with the adhesion layer of this invention. It is a top view explaining the process ((alpha) 1) in manufacture of the transparent surface material with the adhesion layer of 1st Embodiment. It is sectional drawing explaining the process ((alpha) 1) in manufacture of the transparent surface material with the adhesion layer of 1st Embodiment. It is sectional drawing explaining the process ((beta) 1) in manufacture of the transparent surface material with the adhesion layer of 1st Embodiment. It is a top view explaining the process ((alpha) 21) in manufacture of the transparent surface material with the adhesion layer of 2nd Embodiment. It is sectional drawing explaining the process ((alpha) 21) in manufacture of the transparent surface material with the adhesion layer of 2nd Embodiment. It is a top view explaining the process ((alpha) 22) in manufacture of the transparent surface material with the adhesion layer of 2nd Embodiment. It is sectional drawing explaining the process ((alpha) 22) in manufacture of the transparent surface material with the adhesion layer of 2nd Embodiment. It is sectional drawing explaining the process ((beta) 2) in manufacture of the transparent surface material with the adhesion layer of 2nd Embodiment. It is sectional drawing which shows an example of the display apparatus of this invention. It is a perspective view which shows the mode of the bubble in the interface of a display panel and an adhesion layer at the time of bonding a transparent surface material and a display panel through the adhesion layer. It is a graph which shows the relationship between the density | concentration of the hydroxyl group in the adhesion layer in Examples 1-3, and bubble disappearance time. It is a graph which shows the relationship between the sum total of the density | concentration of the hydroxyl group in the adhesion layer in Examples 1-3, and the density | concentration of a urethane bond, and bubble disappearance time. It is a graph which shows the relationship between the density | concentration of the hydroxyl group in the adhesion layer in Examples 4-6, and bubble disappearance time. It is a graph which shows the relationship between the sum total of the density | concentration of the hydroxyl group in the adhesion layer in Examples 4-6, and the density | concentration of a urethane bond, and bubble disappearance time.

The following definitions of terms apply throughout this specification and the claims.
“Transparent” in the transparent surface material means that after the surface material and the display surface of the display panel are bonded to each other through the adhesive layer without bubbles and / or voids, the whole or a part of the display image on the display panel is optical. It means a state that can be visually recognized through the face material without receiving any significant distortion. Therefore, even if part of the light incident on the face material from the display panel is absorbed and reflected by the face material, or the visible material has a low visible ray transmittance due to a change in optical phase, the surface If the display image on the display panel can be viewed through the material without optical distortion, it can be said to be “transparent”.
The “liquid curable resin composition” means that the curable resin composition is in a liquid state without containing a solvent.
The “cured product of the curable resin composition” is a product obtained by curing the curable resin composition until the storage shear modulus at 35 ° C. becomes the target storage shear modulus at 35 ° C. means.
“Partially cured product” means that the curable resin composition is cured until the storage shear modulus at 35 ° C. becomes 1/200 to 1/5 of the storage shear modulus at 35 ° C. of the target adhesive layer. Means something.
“Oligomer” is a compound having a molecular chain composed of repeating structural units (oxyalkylene units, diene units, etc.), and means having a number average molecular weight of 1,000 to 100,000.
The “low molecular weight polymerizable compound” means a compound having an addition polymerizable unsaturated double bond and a molecular weight of 600 or less.
“(Meth) acrylate” means acrylate or methacrylate.
“Viscosity” is a value measured using an E-type viscometer at 25 ° C.
“Number average molecular weight of curable oligomer (A)” is a number average molecular weight in terms of polystyrene determined by gel permeation chromatography (hereinafter referred to as GPC). In addition, in GPC, when the peak of an unreacted low molecular weight component (monomer etc.) appears, this peak is excluded and a number average molecular weight is calculated | required.
The “number average molecular weight of the non-curable oligomer (C1)” is the hydroxyl value A (KOH mg / g) measured in accordance with JIS K1557-1: 2007 and the non-curable oligomer (C) in one molecule. It is a value calculated from the number B of hydroxyl groups by the following formula.
-Number average molecular weight of non-curable oligomer (C) = 56.1 x B x 1000 / A
“Adhesion layer solubility parameter” (hereinafter also referred to as SP value) is a solubility parameter of a cured product of the curable resin composition calculated using the Fedors formula. For specific calculation methods, refer to the following documents.
Hideki Yamamoto, “SP Value Basics / Applications and Calculation Methods”, Information Organization Co., Ltd.
“Storage shear modulus of adhesive layer (or weir) at 35 ° C.” is measured using a rheometer (Modular Rheometer Physica MCR-301, manufactured by Anton Paar) and a measuring spindle and a transparent plate. The gap is the same as the thickness of the adhesive layer (or weir), an uncured curable resin composition is placed in the gap, and heat and light necessary for curing are added to the uncured curable resin composition, The storage shear modulus of the curing process is measured at a measurement frequency of 1 Hz, and the measured value in the curing condition when forming the adhesive layer (or weir) is defined as the storage shear modulus of the adhesive layer (or weir).

<Transparent surface material with adhesive layer>
The transparent surface material with an adhesive layer of the present invention has a transparent surface material and an adhesive layer made of a cured product of a curable resin composition for forming an adhesive layer formed on the surface of the transparent surface material. The adhesive layer may be formed on at least one surface of the transparent surface material, or may be formed on both surfaces of the transparent surface material.
The transparent surface material with an adhesive layer of the present invention may further have a frame-like weir surrounding the adhesive layer in contact with the periphery of the adhesive layer, if necessary.
The transparent surface material with an adhesive layer of the present invention may further have a peelable protective film that covers the surface of the adhesive layer, if necessary.

(Transparent surface material)
As a form of the transparent surface material, a protective plate provided on the image display surface side (viewing side) of the display panel to protect the display panel; a coordinate provided on the contacted side (viewing side) of a coordinate input device such as a touch panel A protective plate for protecting the input device; for example, a substrate with a transparent electrode constituting a touch panel portion in a display device with a touch panel.

  Examples of the transparent face material include a glass plate or a transparent resin plate. The glass plate is not only highly transparent with respect to light emitted from and reflected from the display panel, but also has light resistance, low birefringence, high planar accuracy, surface scratch resistance, and high mechanical strength. Is most preferred. A glass plate is also preferred from the viewpoint of sufficiently transmitting light for curing the photocurable resin composition in the production process described later.

  Examples of the material of the glass plate include glass materials such as soda lime glass, and high transmittance glass (also referred to as white plate glass) having lower iron content and less bluishness is more preferable. Tempered glass may be used to increase safety. In particular, when a thin glass plate is used, it is preferable to use a chemically strengthened glass plate. Examples of the material of the transparent resin plate include highly transparent resin materials (such as polycarbonate and polymethyl methacrylate).

  The transparent face material may be subjected to a surface treatment in order to improve the adhesion with the adhesive layer. Examples of the surface treatment method include a method of treating the surface of the transparent surface material with a silane coupling agent, a method of forming a silicon oxide thin film by an oxidation flame using a frame burner, and the like.

(Adhesive layer)
The pressure-sensitive adhesive layer is a layer made of a transparent resin obtained by curing a liquid pressure-sensitive adhesive layer-forming curable resin composition.

The concentration of the hydroxyl group in the adhesive layer is 100 × 10 ⁻⁶ to 600 × 10 ⁻⁶ mol / g, preferably 250 × 10 ^{−6 to} 550 × 10 ⁻⁶ mol / g, and 300 × 10 ^{−6 to} 500. × 10 ⁻⁶ mol / g is more preferable. If the concentration of the hydroxyl group in the adhesive layer is 100 × 10 ⁻⁶ mol / g or more, the adhesiveness between the adhesive layer and the transparent surface material, and the adhesiveness between the adhesive layer and the object to be bonded (display panel, etc.) It becomes good.
In particular, when the concentration of the hydroxyl group in the adhesive layer is 250 × 10 ⁻⁶ mol / g or more, when the bonding between the transparent surface material with the adhesive layer and the object to be bonded (such as a display panel) fails, In order to reuse the bonded material, when the transparent surface material with the adhesive layer is peeled off from the material to be bonded, the pressure-sensitive adhesive layer is difficult to cohesively break down, and a part of the pressure-sensitive adhesive layer hardly remains in the material to be bonded. When even a little adhesive layer remains on the object to be bonded, the object to be bonded cannot be reused.
If the density | concentration of the hydroxyl group in an adhesion layer is 600x10 < ^-6 > mol / g or less, when bonding with a transparent surface material with an adhesion layer and a to-be-bonded object, it will be in the interface of a to-be-bonded object and an adhesion layer. The remaining bubbles can disappear quickly.

The concentration of the hydroxyl group in the adhesive layer is the concentration of the hydroxyl group in each raw material of the first composition such as the curable oligomer (A), the low molecular weight polymerizable compound (B), and the non-curable oligomer (C), which will be described later. Calculated from the mixing ratio of raw materials.
The density | concentration of the hydroxyl group of a curable oligomer (A) and a non-curable oligomer (C) is calculated | required by calculation from the molar ratio of the raw material at the time of synthesize | combining an oligomer. The hydroxyl group concentration of the low molecular weight polymerizable compound (B) is determined by calculation from the molecular weight and the number of functional groups.
The concentration of the hydroxyl group in the adhesive layer is the concentration of the hydroxyl group in each raw material of the first composition such as the curable oligomer (A), the low molecular weight polymerizable compound (B), and the non-curable oligomer (C), which will be described later. It can adjust within the said range by adjusting the compounding ratio of a raw material.

The concentration of urethane bonds in the adhesive layer is 0 to 150 × 10 ⁻⁶ mol / g, preferably 30 × 10 ^{−6 to} 95 × 10 ⁻⁶ mol / g, and 50 × 10 ^{−6 to} 90 × 10 ^{−. 6} mol / g is more preferable. In particular, when the concentration of urethane bonds in the adhesive layer is 30 × 10 ⁻⁶ mol / g or more, the adhesive layer is less likely to cohesively break down when the transparent surface material with the adhesive layer is peeled off from the object to be bonded. Part of the layer hardly remains on the object to be bonded. If the density | concentration of the urethane bond in an adhesion layer is 150x10 < ^-6 > mol / g or less, when bonding with a transparent surface material with an adhesion layer and a to-be-bonded object, the interface of a to-be-bonded object and an adhesion layer The bubbles remaining in the gas can disappear quickly.
The pressure-sensitive adhesive layer preferably has no urethane bond from the viewpoint of the disappearance of bubbles, but preferably has a urethane bond when it is desired to increase the curing rate of the curable oligomer (A).

The concentration of urethane bonds in the adhesive layer is the concentration of urethane bonds in each raw material of the first composition such as curable oligomer (A), low molecular weight polymerizable compound (B), and non-curable oligomer (C) described later. And it calculates | requires by calculation from the compounding ratio of each raw material.
The concentration of the urethane bond in the curable oligomer (A) and the non-curable oligomer (C) is determined by calculation from the molar ratio of raw materials when the oligomer is synthesized. The concentration of the urethane bond of the low molecular weight polymerizable compound (B) is determined by calculation from the molecular weight and the number of functional groups.
The concentration of urethane bonds in the adhesive layer is the concentration of urethane bonds in each raw material of the first composition such as curable oligomer (A), low molecular weight polymerizable compound (B), and non-curable oligomer (C) described later. And it can adjust within the said range by adjusting the compounding ratio of each raw material.
Especially, when it is a combination of the curable oligomer (A1), the low molecular weight polymerizable compound (B1) and the non-curable oligomer (C1), the concentration of the urethane bond contained in the curable oligomer (A1) and each raw material By adjusting both of the blending ratios, it can be adjusted within the above range.

The total of the concentration of hydroxyl groups in the adhesive layer and the concentration of urethane bonds in the adhesive layer is preferably 100 × 10 ^{−6 to} 750 × 10 ⁻⁶ mol / g, and 250 × 10 ⁻⁶ to 600 × 10 ⁻⁶ mol. / G is more preferable. When the sum of the concentration of hydroxyl groups in the adhesive layer and the concentration of urethane bonds in the adhesive layer is 100 × 10 ⁻⁶ mol / g or more, the curing rate of the curable oligomer (A) is high, and the adhesive layer and the transparent layer are transparent. Adhesion with the face material and adhesion between the adhesive layer and the object to be bonded (display panel or the like) are improved.
In particular, when the total of the concentration of the hydroxyl group in the adhesive layer and the concentration of the urethane bond in the adhesive layer is 250 × 10 ⁻⁶ mol / g or more, the transparent surface material with the adhesive layer is peeled from the object to be bonded. In addition, the adhesive layer is difficult to cohesively break, and a part of the adhesive layer hardly remains on the object to be bonded. When the total of the concentration of the hydroxyl group in the adhesive layer and the concentration of the urethane bond in the adhesive layer is 600 × 10 ⁻⁶ mol / g or less, when the transparent surface material with the adhesive layer and the object to be bonded are bonded together. In addition, bubbles remaining at the interface between the object to be bonded and the adhesive layer can disappear more rapidly.

The solubility parameter of the adhesive layer (that is, the cured product of the curable resin composition for forming the adhesive layer) is preferably 17.5 to 18.5 (J / cm ³ ) ^1/2 , and 18.0 to 18.45 (J / Cm ³ ) ^1/2 is more preferable. When the solubility parameter is 17.5 (J / cm ³ ) ^1/2 or more, the adhesiveness between the adhesive layer and the transparent surface material and the adhesiveness between the adhesive layer and the object to be bonded (display panel, etc.) are good. It becomes. If the solubility parameter is 18.5 (J / cm ³ ) ^1/2 or less, it remains at the interface between the object to be bonded and the adhesive layer when it is bonded to the transparent surface material with the adhesive layer and the object to be bonded. Bubbles can disappear more quickly.

The storage shear modulus at 35 ° C. of the adhesive layer is preferably 1 × 10 ^{3 to} 300 × 10 ³ Pa, more preferably 1 × 10 ^{3 to} 100 × 10 ³ Pa, and more preferably 1 × 10 ³ to 50 × 10 ³ Pa. Further preferred. If the storage shear modulus is 1 × 10 ³ Pa or more, the shape of the adhesive layer can be maintained. Moreover, even when the thickness of the adhesive layer is relatively large, the thickness can be kept uniform throughout the adhesive layer, and when the transparent surface material with the adhesive layer and the display panel are bonded, Air bubbles are unlikely to occur at the interface with the layer. When the storage shear modulus is 300 × 10 ³ Pa or less, the adhesive layer can exhibit good adhesion when bonded to a display panel.
In addition, since the molecular mobility of the cured product of the first composition constituting the adhesive layer is relatively high, after bonding the display panel and the transparent surface material with the adhesive layer under a reduced pressure atmosphere, the atmospheric pressure atmosphere The difference between the pressure inside the bubble (that is, the pressure of the reduced pressure atmosphere in the reduced pressure state) and the pressure applied to the adhesive layer (that is, the atmospheric pressure when returned to the atmospheric pressure atmosphere) The volume of the bubbles is easily reduced by the pressure, and the gas in the bubbles with the reduced volume is easily dissolved and absorbed in the adhesive layer.

The thickness of the adhesive layer is preferably 0.03 to 2 mm, and more preferably 0.1 to 0.8 mm. If the thickness of the pressure-sensitive adhesive layer is 0.03 mm or more, the pressure-sensitive adhesive layer effectively buffers an impact or the like due to an external force from the transparent surface material side, and the display panel or the like can be protected. Further, in the manufacturing method of the display device, even if foreign matter not exceeding the thickness of the adhesive layer is mixed between the display panel and the transparent surface material with the adhesive layer, the thickness of the adhesive layer is not significantly changed. Little impact on transmission performance.
If the thickness of the adhesive layer is 2 mm or less, bubbles hardly remain in the adhesive layer, and the entire thickness of the display device does not become unnecessarily thick. As a method for adjusting the thickness of the adhesive layer, there are a method for adjusting the supply amount of the liquid curable resin composition for forming an adhesive layer supplied to the surface of the transparent surface material, a method for adjusting the thickness of the weir, etc. Can be mentioned.

(Curable resin composition for forming an adhesive layer)
The adhesive layer forming curable resin composition is not particularly limited as long as it can form an adhesive layer. As the curable resin composition for forming an adhesive layer, from the viewpoint of the adhesiveness between the adhesive layer and the transparent surface material and the object to be bonded, and the speed of disappearance of bubbles remaining at the interface between the object to be bonded and the adhesive layer. The 1st composition mentioned later is mentioned preferably.

(First composition)
The first composition comprises a curable oligomer (A) having an addition polymerizable unsaturated double bond, a low molecular weight polymerizable compound (B) having an addition polymerizable unsaturated double bond, and an addition as necessary. And a non-curable oligomer (C) having no polymerizable unsaturated double bond.
When the non-curable oligomer (C) is not included, either one or both of the curable oligomer (A) and the low molecular weight polymerizable compound (B) have a hydroxyl group. Either one or both of the curable oligomer (A) and the low molecular weight polymerizable compound (B) may have a urethane bond.
When the non-curable oligomer (C) is included, at least one of the curable oligomer (A), the low molecular weight polymerizable compound (B), and the non-curable oligomer (C) has a hydroxyl group. At least one of the curable oligomer (A), the low molecular weight polymerizable compound (B), and the non-curable oligomer (C) may have a urethane bond.

The first composition may be a photocurable resin composition or a thermosetting resin composition. The first composition is preferably a photocurable resin composition further blended with a photopolymerization initiator (D) because it can be cured at a low temperature and has a high curing rate. In addition, if the first composition is a photocurable resin composition, a high temperature is not required for curing, so that there is little risk of damage to the display panel or the like due to high temperatures.
The first composition may contain an additive as necessary.

About curable oligomer (A):
The addition polymerizable unsaturated double bond of the curable oligomer (A) is preferably an acryloyloxy group or a methacryloyloxy group, particularly preferably an acryloyloxy group, from the viewpoint of curability of the first composition.
The viscosity of the curable oligomer (A) is preferably 1 to 800 Pa · s, more preferably 2 to 600 Pa · s. When the viscosity of the curable oligomer (A) is within the above range, it is easy to adjust the viscosity of the first composition to a range described later.
A curable oligomer (A) may be used individually by 1 type, and may use 2 or more types together.

The curable oligomer (A) has a number average molecular weight of 1,000 to 100,000 from the viewpoint of the curability of the first composition and the mechanical properties of the adhesive layer, and is an addition polymerizable unsaturated double bond. What mix | blended the curable oligomer (A1) whose average number is 1.8-4 is preferable.
The curable oligomer (A) has a number average molecular weight of 1,000 to 1,000 from the viewpoint that bubbles remaining at the interface between the object to be bonded and the adhesive layer can disappear more quickly and display unevenness of the display device is suppressed. What mix | blended the curable oligomer (A2) which is 20,000 and whose average number of addition polymerizable unsaturated double bonds is 0.5-1 is preferable.
As a curable oligomer (A), what mixed the curable oligomer (A1) and the curable oligomer (A2) is more preferable.

Curable oligomer (A1):
The number average molecular weight of the curable oligomer (A1) is 1,000 to 100,000, and preferably 10,000 to 80,000. When the number average molecular weight of the curable oligomer (A1) is within the above range, it is easy to adjust the viscosity of the first composition to a range described later, and it is easy to form an adhesive layer in which display unevenness is suppressed.

The average number of addition polymerizable unsaturated double bonds of the curable oligomer (A1) is 1.8 to 4 in terms of the curability of the first composition and the mechanical properties of the adhesive layer. 3 is preferred.
As the curable oligomer (A1), it is preferable that the number of addition polymerizable unsaturated double bonds in one molecule is 2 to 4 originally, but when producing the curable oligomer (A1), By-products with less than 2 addition polymerizable unsaturated double bonds may be formed. Therefore, the average number of addition polymerizable unsaturated double bonds of the curable oligomer (A1) is 1.8 to 4 as including by-products.

  As the curable oligomer (A1), those having a polyoxyalkylene chain or a polydiene chain are preferred, and those having a polyoxyalkylene chain are more preferred from the viewpoints of flexibility and heat-and-moisture resistance.

As the curable oligomer (A1) having a polydiene chain, an esterified product of maleic anhydride adduct of polyisoprene polymer and 2-hydroxyethyl methacrylate (Kuraray Co., Ltd., UC102 (number average molecular weight: 17,000, addition polymerization) Average number of polymerizable unsaturated double bonds: 2), UC203 (number average molecular weight: 35,000, average number of addition polymerizable unsaturated double bonds: 3), UC-1 (number average molecular weight: about 25,000) )), (Meth) acrylate oligomers of polybutadiene skeleton and the like.
A curable oligomer (A1) may be used individually by 1 type, and may use 2 or more types together.

As the curable oligomer (A1), the following curable oligomer (A11) or curable oligomer (A12) is particularly preferable from the viewpoint of flexibility. The curable oligomer (A12) will be described later.
Curable oligomer (A11): Urethane acrylate obtained by reacting polyol and polyisocyanate to obtain a prepolymer having an isocyanate group at the terminal, and then reacting the following monomer (a1) with the isocyanate group of the prepolymer Oligomer.
Monomer (a1): A monomer having a molecular weight of 125 to 600, one or more acryloyloxy groups, and one group that reacts with an isocyanate group.

Examples of the monomer (a1) include monomers having an active hydrogen-containing group (hydroxyl group, amino group, etc.) and an acryloyloxy group.
Specific examples of the monomer (a1) include hydroxyalkyl acrylates having a C2-C6 hydroxyalkyl group (2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 4-hydroxybutyl acrylate, etc.). Etc.
As the monomer (a1), a hydroxyalkyl acrylate having a C2-C4 hydroxyalkyl group is preferred.
A monomer (a1) may be used individually by 1 type, and may use 2 or more types together.

Specific examples of the polyol include polyoxyalkylene polyols (polyoxyethylene glycol, polyoxypropylene polyol, etc.), polyester polyols, polycarbonate polyols, and the like. The polyol is preferably a polyoxyalkylene polyol, more preferably a polyoxypropylene polyol, from the viewpoint of flexibility.
Moreover, the polyoxyalkylene polyol which has an oxypropylene group and an oxyethylene group is more preferable from the point which improves compatibility with the other component of a 1st composition. Moreover, the polyoxyalkylene polyol which has a polyoxyalkylene chain which consists only of an oxyethylene group and an oxypropylene group is especially preferable from the point that a highly flexible hardened | cured material is easy to be obtained also in a low temperature range.

The number average molecular weight of the polyol is preferably 4,000 or more, and more preferably 8,000 or more, from the viewpoint of lowering the concentration of urethane bonds in the first composition. The number average molecular weight of the polyol is preferably 45,000 or less, more preferably 35,000 or less, from the viewpoint that the viscosity of the first composition is easily within the range described below.
A polyol may be used individually by 1 type and may use 2 or more types together.

The polyisocyanate is preferably at least one diisocyanate selected from the group consisting of aliphatic diisocyanates, alicyclic diisocyanates and non-yellowing aromatic diisocyanates.
Examples of the aliphatic polyisocyanate include hexamethylene diisocyanate, 2,2,4-trimethyl-hexamethylene diisocyanate, and 2,4,4-trimethyl-hexamethylene diisocyanate.
Examples of the alicyclic polyisocyanate include isophorone diisocyanate and methylene bis (4-cyclohexyl isocyanate).
Examples of the non-yellowing aromatic diisocyanate include xylylene diisocyanate.
Polyisocyanate may be used individually by 1 type and may use 2 or more types together.

  In the reaction between the polyol and the polyisocyanate, the ratio of the number of moles of isocyanate groups to the number of moles of hydroxyl groups (isocyanate group / hydroxyl group) is preferably from 1/1 to 1.8 / 1, preferably from 1.05 / 1 or more. 1.5 / 1 or less is more preferable. When the isocyanate group / hydroxyl group is within the above range, it is easy to adjust the viscosity of the first composition to the range described later.

As a method of adjusting the average number of addition polymerizable unsaturated double bonds of the curable oligomer (A11) to 1.8 to 4, there is a method of adjusting the mixing ratio of the raw materials used for the production of the curable oligomer (A11). Examples thereof include the following methods (i) and (ii).
(I) In the case of the curable oligomer (A11) having an average number of addition polymerizable unsaturated double bonds of 1.8 to 2:
A polyol having an average number of hydroxyl groups of 1.8 to 2 and a polyisocyanate having an average number of isocyanate groups of 2 were reacted to obtain a prepolymer having an average number of isocyanate groups of 1.8 to 2. Thereafter, the monomer (a11) having one addition polymerizable unsaturated double bond and one hydroxyl group in one molecule is reacted so that the ratio of the number of moles of isocyanate group / hydroxyl group is 1/1.
(Ii) In the case of the curable oligomer (A11) having an average number of addition polymerizable unsaturated double bonds of 2 to 4:
A polyol having an average number of hydroxyl groups of 2 and a polyisocyanate having an average number of isocyanate groups of 2 are reacted to obtain a prepolymer having an average number of isocyanate groups of 2, and then hydroxyl groups in one molecule. The monomer (a12) having one and having at least one addition polymerizable unsaturated double bond has a ratio of the number of moles of isocyanate group / hydroxyl group of 1/1, and the average number of addition polymerizable unsaturated double bonds is The method of making it react so that it may become 2-4.

The curable oligomer (A12) is the following oligomer.
Curable oligomer (A12): A urethane acrylate oligomer obtained by reacting a polyol with a compound having one isocyanate group and one addition polymerizable double bond.
As a polyol, the thing similar to what was used for manufacture of a curable oligomer (A11) can be used.
As the compound having one isocyanate group and one addition polymerizable double bond, for example, a compound represented by CH ₂ ═C (R) C (O) O—R ¹ —NCO (where R is a hydrogen atom or methyl) And R ¹ is an alkylene group having 1 to 6 carbon atoms). Such compounds include Karenz MOI (registered trademark) (manufactured by Showa Denko KK, R is a methyl group, R ¹ has 2 carbon atoms), Karenz AOI (registered trademark) (manufactured by Showa Denko KK, R is a hydrogen atom, And R ¹ has 2 carbon atoms.

Curable oligomer (A2):
The number average molecular weight of the curable oligomer (A2) is 1,000 to 20,000, preferably 2,000 to 10,000. When the number average molecular weight of the curable oligomer (A2) is within this range, it is easy to form an adhesive layer that can easily adjust the viscosity of the first composition to a range described later.
When the curable oligomer (A) contains the curable oligomer (A2), it is easy to adjust the viscosity of the first composition to a range described later. Since the curable oligomer (A2) has substantially no hydroxyl group, the viscosity of the first composition can be adjusted without adversely affecting the disappearance of bubbles.

  Examples of the addition polymerizable unsaturated double bond of the curable oligomer (A2) include an acryloyloxy group and a methacryloyloxy group. The addition polymerizable unsaturated double bond of the curable oligomer (A2) is preferably an acryloyloxy group or a methacryloyloxy group from the viewpoint of a high curing rate and a highly transparent adhesive layer. An acryloyloxy group is particularly preferred because the difference in the reactivity of the addition polymerizable unsaturated double bond between (A2) and the low molecular weight polymerizable compound (B) is reduced, and a homogeneous adhesive layer is formed.

The average number of addition polymerizable unsaturated double bonds of the curable oligomer (A2) is 0.5 to 1 in terms of the curability of the first composition and the mechanical properties of the adhesive layer, and 0.7 to 1 is preferred. When the number of addition polymerizable unsaturated double bonds exceeds 1, it becomes an oligomer having crosslinkability, and the storage shear modulus of the cured product of the curable resin composition tends to increase. Therefore, the stress applied to the display panel bonded to the adhesive layer is increased, and display unevenness of the display device is likely to occur.
Further, the fluidity of the adhesive layer is lost, and bubbles generated at the interface between the adhesive layer and the display panel during bonding are likely to remain. Therefore, it is preferable to select a raw material at the time of producing the curable oligomer (A2) so that the number of addition polymerizable unsaturated double bonds exceeding 1 is not included.
A curable oligomer (A2) may be used individually by 1 type, and may use 2 or more types together.

As the curable oligomer (A2), the following curable oligomer (A21) is preferable from the viewpoint of flexibility.
Curable oligomer (A21): obtained by reacting monool and polyisocyanate to obtain a prepolymer having an isocyanate group only at one end, and then reacting monomer (a1) with the isocyanate group of the prepolymer. Urethane monoacrylate oligomer.

  Examples of the monomer (a1) and polyisocyanate used for the production of the curable oligomer (A21) include the same monomers as those used for the production of the curable oligomer (A11), and preferred embodiments are also the same. Examples of the monool include those similar to those used in the production of the curable oligomer (A11) except for the number of hydroxyl groups, and preferred embodiments are also the same. The number of preferable hydroxyl groups of monool is 0.5 to 1 in one molecule, and 0.7 to 1 is more preferable.

As a method of adjusting the average number of addition polymerizable unsaturated double bonds of the curable oligomer (A21) to 0.5 to 1, there is a method of adjusting the blending ratio of raw materials used for the production of the curable oligomer (A21). Examples thereof include the following methods (iii) and (iv).
(Iii) A prepolymer having a mean number of isocyanate groups of 0.5 to 1 by reacting monool and diisocyanate at a ratio of isocyanate group / hydroxyl mole number of 1/1 to 2/1. And then the monomer (a1) is reacted so that the ratio of the number of moles of the isocyanate group / the group reacting with the isocyanate group is 1/1.
(Iv) The monool is reacted with a compound having one acryloyloxy group and one isocyanate group in one molecule at a ratio in which the molar ratio of isocyanate group / hydroxyl group is 1/2 to 1/1. And obtaining a compound having an average number of acryloyloxy groups of 0.5 to 1.

About the low molecular weight polymerizable compound (B):
The molecular weight of the low molecular weight polymerizable compound (B) is 600 or less, preferably 140 to 400. The smaller the molecular weight of the low molecular weight polymerizable compound (B), the better the adhesion between the adhesive layer and the transparent surface material, and the adhesion between the adhesive layer and the object to be bonded (display panel, etc.). If the molecular weight of the low molecular weight polymerizable compound (B) is 140 or more, volatilization of the low molecular weight polymerizable compound (B) when the transparent surface material with adhesive layer and the display device are produced by the method described later can be suppressed.

  1-3 are preferable and, as for the number of the addition polymerizable unsaturated double bond of a low molecular weight polymeric compound (B), 1-2 are more preferable. The low molecular weight polymerizable compound (B) is preferably a combination of a compound having one addition polymerizable unsaturated double bond and a compound having two or more addition polymerizable unsaturated double bonds.

Examples of the addition polymerizable unsaturated double bond of the low molecular weight polymerizable compound (B) include an acryloyloxy group and a methacryloyloxy group. The addition polymerizable unsaturated double bond of the low molecular weight polymerizable compound (B) is preferably an acryloyloxy group or a methacryloyloxy group from the viewpoint of a high curing speed and a highly transparent adhesive layer. An acryloyloxy group is particularly preferred because of its high speed.
A low molecular weight polymeric compound (B) may be used individually by 1 type, and may use 2 or more types together.

Low molecular weight polymerizable compound (B1):
As the low molecular weight polymerizable compound (B), the adhesiveness between the adhesive layer and the transparent surface material, the adhesiveness between the adhesive layer and the object to be bonded (display panel, etc.), and the adhesive layer are improved. Incorporating a low molecular weight polymerizable compound (B1) having an addition polymerizable unsaturated double bond and a hydroxyl group bonded to a carbon atom from the viewpoint of easily obtaining a dispersion stabilizing effect of the non-curable oligomer (C1) described later Is preferred.

The number of hydroxyl groups of the low molecular weight polymerizable compound (B1) is determined by the adhesion between the adhesive layer and the transparent surface material or the object to be bonded, and the speed of disappearance of bubbles remaining at the interface between the object to be bonded and the adhesive layer. From the viewpoint, 1 or 2 is preferable, and 1 is particularly preferable.
Examples of the low molecular weight polymerizable compound (B1) having one hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth). Examples thereof include acrylate, 6-hydroxyhexyl methacrylate, and phenyl glycidyl ether acrylate.
Examples of the low molecular weight polymerizable compound (B1) having two hydroxyl groups include glycerin monomethacrylate and 2,3-dihydroxypropyl acrylate.

As the low molecular weight polymerizable compound (B1), hydroxyalkyl methacrylate (2-hydroxypropyl methacrylate) having a hydroxyalkyl group having 3 to 8 carbon atoms from the viewpoint of adhesion between the adhesive layer and the transparent surface material or the object to be bonded. , 2-hydroxybutyl methacrylate, 4-hydroxybutyl methacrylate, etc.) or phenyl glycidyl ether acrylate is preferred, and phenyl glycidyl ether acrylate is particularly preferred.
A low molecular weight polymeric compound (B1) may be used individually by 1 type, and may use 2 or more types together.

Low molecular weight polymerizable compound (B2):
The low molecular weight polymerizable compound (B) may further contain a low molecular weight polymerizable compound (B2) having an addition polymerizable unsaturated double bond and no hydroxyl group.

About non-curable oligomer (C):
The non-curable oligomer (C) does not react with the curable oligomer (A) and the low molecular weight polymerizable compound (B) when the first composition is cured. The non-curable oligomer (C) may or may not have a hydroxyl group.
A non-curable oligomer (C) may be used individually by 1 type, and may use 2 or more types together.

When the non-curable oligomer (C) is included in the first composition, the fluidity of the first composition is increased, and the storage shear modulus of the adhesive layer is reduced. Therefore, the non-curable oligomer (C) is obtained by bonding the transparent surface material with the adhesive layer and the object to be bonded in a reduced pressure atmosphere, and then returning the object to the atmospheric pressure atmosphere. This contributes to shortening the time required for the bubbles generated at the interface of the liquid to disappear.
In addition, the non-curable oligomer (C) can suppress stress applied to the transparent surface material when the first composition is applied to the surface of the transparent surface material and the first composition is cured.
The non-curable oligomer (C) can exert the above-mentioned effect in a small amount, but when it has a weir, the diffusion of the non-curable oligomer (C) from the adhesive layer to the weir occurs, so at the interface between the adhesive layer and the weir. There is a possibility that bubbles may be generated or remain when bonded to an object to be bonded due to deformation (for example, a step). Therefore, it is preferable to use the non-curable oligomer (C) within a range of amounts described later.

Non-curable oligomer (C1):
The non-curable oligomer (C) is a non-curable oligomer (from the point that the adhesiveness between the adhesive layer and the transparent surface material and the adhesiveness between the adhesive layer and the object to be bonded (display panel, etc.) are good. What mix | blended C1) is preferable.

  The average number of hydroxyl groups of the non-curable oligomer (C1) is preferably 0.8 to 3 in terms of compatibility and the speed of disappearance of bubbles remaining at the interface between the object to be bonded and the adhesive layer. 8 to 2.3 is more preferable.

The number average molecular weight per hydroxyl group of the non-curable oligomer (C1) is preferably 400 to 8,000, and more preferably 600 to 5,000. If the number average molecular weight per hydroxyl group is 400 or more, the polarity of the non-curable oligomer (C1) does not become too high, and the curable oligomer (A), the low molecular weight polymerizable compound (B) and other non-cured compounds. Good compatibility with the functional oligomer (C) is easily obtained.
If the number average molecular weight per hydroxyl group is not more than 8,000, after curing due to the interaction between the hydroxyl group derived from the low molecular weight polymerizable compound (B1) and the hydroxyl group of the non-curable oligomer (C1) It is easy to obtain the effect of stabilizing the dispersion of the non-curable oligomer (C1) in the adhesive layer. Such an interaction is presumed to involve hydrogen bonding.
A non-curable oligomer (C1) may be used individually by 1 type, and may use 2 or more types together.

Examples of the non-curable oligomer (C1) include a high molecular weight polyol. The non-curable oligomer (C1) is preferably a polyoxyalkylene polyol, a polyester polyol, a polycarbonate polyol, or a polybutadiene polyol from the viewpoint of flexibility and compatibility.
When the curable oligomer (A) is a urethane acrylate using a polyoxyalkylene polyol as a raw material, the non-curable oligomer (C1) is more preferably a polyoxyalkylene polyol from the viewpoint of better compatibility. .
Examples of the polyoxyalkylene polyol include polyoxyalkylene diols such as polyoxyethylene glycol, polyoxypropylene diol, polyoxypropylene triol, and polyoxytetramethylene glycol.

  As the non-curable oligomer (C1), a polyoxyalkylene polyol is preferable and a polyoxypropylene polyol is particularly preferable because the storage shear modulus of the adhesive layer tends to be low. Further, as the non-curable oligomer (C1), a polyoxyalkylene polyol having an oxypropylene group and an oxyethylene group may be used.

Non-curable oligomer (C2):
The non-curable oligomer (C) may be further blended with a non-curable oligomer (C2) having no hydroxyl group.

  The number average molecular weight of the non-curable oligomer (C2) is preferably 1,000 to 8,000. If the number average molecular weight of the non-curable oligomer (C2) is 1,000 or more, the non-curable oligomer (C2) is difficult to bleed out. If the number average molecular weight of the non-curable oligomer (C2) is 8,000 or less, it becomes easy to adjust the viscosity of the first composition to a range described later.

  Examples of the non-curable oligomer (C2) include compounds in which the hydroxyl group of the non-curable oligomer (C1) is substituted with a group that is not reactive with the acryloyl group, and high molecular weight polydienes. Examples of the polydiene include polybutadiene, polyisoprene, a water additive of polybutadiene, and polybutene. Examples of the compound in which the hydroxyl group of the non-curable oligomer (C1) is substituted with a group that is not reactive with the acryloyl group include polyoxyalkylene polyol alkoxylated products, monocarboxylic oxides, halogenated acetylated products, and esterified products. Can be mentioned.

About the combination of the curable oligomer (A) and the non-curable oligomer (C):
From the point that the curable oligomer (A) and the non-curable oligomer (C) stabilize the mixed state of the first composition before curing and suppress the separation of the non-curable oligomer (C) from the adhesive layer. It is preferable to have molecular chains having the same structure or a similar structure.

Specifically, it is preferable to use a compound having a hydroxyl group (hereinafter referred to as a hydroxyl group-containing compound) as a raw material for the curable oligomer (A) and to use the same hydroxyl group-containing compound as the non-curable oligomer (C). .
In the first composition, the curable oligomer (A) is a urethane acrylate oligomer synthesized using polyoxyalkylene polyol and polyisocyanate as raw materials, and the non-curable oligomer (C) is a polyoxyalkylene polyol. It is preferable in terms of compatibility.

  Even when the hydroxyl group-containing compound used as the raw material of the curable oligomer (A) and the hydroxyl group-containing compound used as the non-curable oligomer (C) are not the same, these hydroxyl group-containing compounds are structural units having a common molecular chain (oxyalkylene). It is preferable that they have a partially common structure, such as having units and diene units, and have the same polarity. If the curable oligomer (A) and the non-curable oligomer (C) partially have the same molecular structure, the compatibility of the non-curable oligomer (C) in the first composition is further increased. .

Preferred combinations when the hydroxyl group-containing compound used as the raw material for the curable oligomer (A) and the hydroxyl group-containing compound used as the non-curable oligomer (C) are not the same include the following combinations.
The curable oligomer (A) is a urethane acrylate oligomer synthesized using a polyoxypropylene polyol in which a part of the oxypropylene group is substituted with an oxyethylene group and a polyisocyanate as raw materials, and a non-curable oligomer (C ) Is a polyoxypropylene polyol having no oxyethylene group, and is a polyoxypropylene polyol having a molecular weight per hydroxyl group smaller than that of the polyol used in the curable oligomer (A).

As a combination of the curable oligomer (A) and the non-curable oligomer (C), the following combinations are particularly preferable.
The curable oligomer (A) is reacted with a polyoxyalkylene diol having an oxypropylene group and an oxyethylene group and a polyisocyanate to obtain a prepolymer having an isocyanate group at the terminal, and then reacted with a monomer (a1). A polyoxyalkylene diol having an oxypropylene group and an oxyethylene group, or an oxypropylene group, the same as that used for the curable oligomer (A). A combination of polyoxypropylene diols having a molecular weight smaller than that of the diol used in the curable oligomer (A).

About photopolymerization initiator (D):
Examples of the photopolymerization initiator (D) include acetophenone, ketal, benzoin, benzoin ether, phosphine oxide, benzophenone, thioxanthone, and quinone photopolymerization initiators. As the photopolymerization initiator (D), phosphine oxide and thioxanthone photopolymerization initiators are preferable, and phosphine oxide is particularly preferable from the viewpoint of suppressing coloring after the photopolymerization reaction.

About additives:
Additives include polymerization inhibitors, photocuring accelerators, chain transfer agents, light stabilizers (ultraviolet absorbers, radical scavengers, etc.), antioxidants, flame retardants, adhesion improvers (silane coupling agents) Etc.), pigments, dyes and the like. As an additive added to the first composition, a polymerization inhibitor and a light stabilizer are preferable. In particular, the storage stability of the first composition can be improved by including a smaller amount of the polymerization inhibitor than the polymerization initiator, and the molecular weight of the cured product of the first composition can also be adjusted.

Examples of the polymerization inhibitor include polymerization inhibitors such as hydroquinone (2,5-di-tert-butylhydroquinone, etc.), catechol (p-tert-butylcatechol, etc.), anthraquinone, phenothiazine, hydroxytoluene, and the like. Can be mentioned.
Examples of the light stabilizer include ultraviolet absorbers (benzotriazole series, benzophenone series, salicylate series, etc.), radical scavengers (hindered amine series), and the like.
Examples of the antioxidant include hindered phenol compounds, phosphorus compounds, and sulfur compounds.

About the mixing ratio of each raw material:
The ratio of the low molecular weight polymerizable compound (B) in the first composition is preferably 1 to 80% by mass in the total (100% by mass) of the curable oligomer (A) and the low molecular weight polymerizable compound (B). 3-70 mass% is more preferable.
If the ratio of a low molecular weight polymeric compound (B1) is more than the said lower limit, the storage stability of a 1st composition will become favorable, and the adhesiveness of an adhesion layer and a transparent surface material, and an adhesion layer and to-be-adhered Adhesion with compound (display panel, etc.) is improved.
The proportion of the low molecular weight polymerizable compound (B2) is preferably 50% by mass or less of the total (100% by mass) of the curable oligomer (A) and the low molecular weight polymerizable compound (B) in the first composition. The mass% or less is more preferable.

  In the synthesis of the curable oligomer (A11) or the curable oligomer (A21), the monomer (a1) that has reacted with the isocyanate group of the prepolymer exists as a part of the curable oligomer (A), so that low molecular weight polymerization is performed. Not included in the ratio of the active compound (B). On the other hand, a low molecular weight polymerizable compound (however, which does not react with the prepolymer) added as a diluent as a diluent during or after the synthesis of the curable oligomer (A11) or the curable oligomer (A21) is low. When falling under the molecular weight polymerizable compound (B), the low molecular weight polymerizable compound is included in the ratio of the low molecular weight polymerizable compound (B).

  When the first composition contains the non-curable oligomer (C), the proportion of the non-curable oligomer (C) is preferably 1 to 60% by mass in the first composition (100% by mass). If the ratio of a non-curable oligomer (C) is more than the said lower limit, a bubble will not remain easily between an adhesion layer and a to-be-bonded thing. If the ratio of a non-curable oligomer (C) is below the said upper limit, if a pressure sensitive adhesive layer fully hardens, it will become easy to peel a protective film from a pressure sensitive adhesive layer.

  In the case where the first composition contains a non-curable oligomer (C), curing is performed out of the total (100% by mass) of the curable oligomer (A), the low molecular weight polymerizable compound (B), and the non-curable oligomer (C). The curable oligomer (A) is preferably 6 to 80% by mass, the low molecular weight polymerizable compound (B) is preferably 3 to 70% by mass, and the non-curable oligomer (C) is preferably 1 to 60% by mass. It is more preferable that A) is 6 to 60% by mass, the low molecular weight polymerizable compound (B) is 3 to 55% by mass, and the non-curable oligomer (C) is 1 to 60% by mass.

The blending amount of the photopolymerization initiator (D) in the first composition is preferably 0.01 to 10 parts by mass with respect to a total of 100 parts by mass of the curable oligomer (A) and the low molecular weight polymerizable compound (B). 0.1 to 5 parts by mass is more preferable.
The compounding amount of the additive in the first composition is preferably 10 parts by mass or less and more preferably 5 parts by mass or less with respect to 100 parts by mass in total of the curable oligomer (A) and the low molecular weight polymerizable compound (B). .

Regarding the viscosity of the first composition:
The viscosity of the first composition is preferably 0.05 to 50 Pa · s, more preferably 1 to 20 Pa · s. If the viscosity of the first composition is 0.05 Pa · s or more, the application shape of the first composition is maintained when the adhesive layer is formed. If the viscosity of the first composition is 50 Pa · s or less, it is easy to supply the first composition to the surface of the transparent surface material, and the productivity of the transparent surface material with an adhesive layer is good.

(Weir)
The weir is a portion made of a transparent resin formed by applying and curing a liquid curable resin composition for forming a weir.

  By having a weir at the periphery of the adhesive layer, it is possible to prevent the peripheral portion of the adhesive layer from spreading outward and thinning the peripheral portion, and to keep the entire thickness of the adhesive layer uniform. By making the whole thickness of the pressure-sensitive adhesive layer uniform, it is preferable that air bubbles remain at the interface in bonding with an object to be bonded (for example, a display panel or the like).

  When it has a weir, the thickness of the weir is slightly thicker than the thickness of the adhesive layer. Even if the surface of the adhesive layer is not flat and the thickness of the adhesive layer is not constant, the thickness of the weir is slightly larger than the thickness of the adhesive layer in at least a part of the area where the weir is adjacent to the adhesive layer It is preferable.

  The thickness of the weir is preferably approximately equal to the average thickness of the adhesive layer excluding the region where the weir and the adhesive layer are close to each other, or, as described above, 0.005 to 0.05 mm thicker than the thickness of the adhesive layer. More preferably, the thickness is 0.01 to 0.03 mm thick.

  Since the area outside the image display area of the display panel is relatively narrow, the width of the weir is preferably narrow. The width of the weir is preferably 0.5 to 2 mm, and more preferably 0.8 to 1.6 mm.

The storage shear modulus at 35 ° C. of the weir is preferably larger than the storage shear modulus at 35 ° C. of the adhesive layer. When the storage shear elastic modulus of the weir is larger than the storage shear elastic modulus of the adhesive layer, the object to be bonded is bonded at the periphery of the adhesive layer when the object to be bonded and the transparent surface material with the adhesive layer are bonded. Even if air bubbles remain at the interface between the adhesive layer and the adhesive layer, the air bubbles are not easily released to the outside, and become independent air bubbles.
Therefore, after bonding the object to be bonded and the transparent surface with the adhesive layer in a reduced pressure atmosphere, when this is returned to the atmospheric pressure atmosphere, the pressure inside the bubbles (that is, the reduced pressure of the reduced pressure atmosphere remains ) And the pressure applied to the adhesive layer (that is, the atmospheric pressure when the pressure is returned to the atmospheric pressure), the volume of the bubbles is reduced, and the bubbles tend to disappear.
Further, by making the storage shear modulus of the weir larger than the storage shear modulus of the adhesive layer, the thickness of the weir is slightly smaller than the thickness of the adhesive layer in at least a part of the region where the weir is close to the adhesive layer. It is easy to produce a transparent face material with a large adhesive layer.

(Curable resin composition for weir formation)
Examples of the curable resin composition for weir formation include a composition containing a silicone resin (organopolysiloxane), a urethane oligomer, a urethane acrylate oligomer, and the like.
As the weir-forming curable resin composition, a composition containing an oligomer (F) and a monomer (G) (hereinafter referred to as a second composition) is preferable from the viewpoints of flexibility and curing speed.

(Second composition)
The second composition may be a photocurable resin composition or a thermosetting resin composition. As a 2nd composition, it is preferable that it is a photocurable resin composition with which the photoinitiator (E) was further mix | blended from the point which can be hardened | cured at low temperature and a cure rate is quick. In addition, if the second composition is a photocurable resin composition, a high temperature is not required for curing, so there is little risk of damage to the display panel due to high temperatures.
Moreover, you may use the thing of the same composition as a 1st composition as a 2nd composition. In this case, in the step (α21) to be described later, the second composition is applied to the peripheral edge of the surface of the transparent face material and semi-cured to form a weir.

The second composition may contain an additive as necessary.
Moreover, in order to maintain the space | interval of a transparent surface material and a display panel, you may mix | blend the spacer particle | grains of a predetermined particle diameter with a 2nd composition.

About oligomer (F):
The oligomer (F) is a compound having an addition polymerizable unsaturated double bond and a number average molecular weight of 30,000 to 100,000.

  Examples of the addition polymerizable unsaturated double bond of the oligomer (F) include an acryloyloxy group and a methacryloyloxy group. As the addition polymerizable unsaturated double bond of the oligomer (F), an acryloyloxy group or a methacryloyloxy group is preferable from the viewpoint that a curing rate is high and a highly transparent weir is obtained. Moreover, the difference in the reactivity of the addition polymerizable unsaturated double bond between the oligomer (F) and the monomer (G) is reduced, and a homogeneous weir can be formed. It is particularly preferable that the double bond is an acryloyloxy group and the addition polymerizable unsaturated double bond of the monomer (G) is a methacryloyloxy group.

The number average molecular weight of the oligomer (F) is 30,000 to 100,000, preferably 40,000 to 80,000, and more preferably 50,000 to 65,000. If the number average molecular weight of an oligomer (F) is in the said range, it will be easy to adjust the viscosity of a 2nd composition to the range mentioned later.
The average number of addition polymerizable unsaturated double bonds of the oligomer (F) is preferably 1.8 to 4 from the viewpoint of curability of the second composition and mechanical properties of the weir.

Examples of the oligomer (F) include a urethane oligomer having a urethane bond, a poly (meth) acrylate of a polyoxyalkylene polyol, and a poly (meth) acrylate of a polyester polyol.
Urethane oligomers synthesized using polyols and polyisocyanates as raw materials are preferred from the viewpoint that the mechanical properties of the weir after curing, adhesion to the transparent surface material, and the like can be widely adjusted by molecular design of the urethane chain, which will be described later. The oligomer (F1) obtained by the synthesis method is more preferable. As the polyol, polyoxyalkylene polyol is more preferable.

Oligomer (F1):
Since the oligomer (F1) having a number average molecular weight in the range of 30,000 to 100,000 has high viscosity, it is difficult to synthesize by a normal method, and even if synthesized, it is difficult to mix with the monomer (G).
Therefore, after synthesizing the oligomer (F1) by a synthesis method using the monomer (G) (the following monomer (G1) and monomer (G2)), the obtained product is used as it is as the second composition, or It is preferable that the obtained product is further diluted with a monomer (G) (the following monomer (G1) to monomer (G3) or the like) to be used as the second fat composition.
Monomer (G1): Monomer (G) that has an addition-polymerizable unsaturated double bond and does not have a group that reacts with an isocyanate group.
Monomer (G2): Monomer (G) having an addition polymerizable unsaturated double bond and a group that reacts with an isocyanate group.
Monomer (G3): Monomer (G) having an addition polymerizable unsaturated double bond and a hydroxyl group.

The oligomer (F1) is obtained by the following synthesis method.
A method in which a polyol and polyisocyanate are reacted in the presence of the monomer (G1) used as a diluent to obtain a prepolymer having an isocyanate group, and then the monomer (G2) is reacted with the isocyanate group of the prepolymer.

As a polyol, the thing similar to the polyol illustrated by the 1st composition is mentioned. The polyol may be the same as or different from the first composition, but the same is preferable. Moreover, the polyoxyalkylene polyol which has an oxypropylene group and an oxyethylene group is more preferable from the point which improves compatibility with the other component of a 2nd composition.
A polyol may be used individually by 1 type and may use 2 or more types together.

Examples of the polyisocyanate include the same polyisocyanates exemplified in the first composition. The polyisocyanate may be the same as or different from the first composition, but the same is preferable.
Polyisocyanate may be used individually by 1 type and may use 2 or more types together.

About monomer (G):
The monomer (G) is a compound having an addition polymerizable unsaturated double bond and a molecular weight of 125 to 600.

  Examples of the addition polymerizable unsaturated double bond of the monomer (G) include an acryloyloxy group and a methacryloyloxy group. As the addition polymerizable unsaturated double bond of the monomer (G), an acryloyloxy group or a methacryloyloxy group is preferable from the viewpoint that a curing rate is high and a highly transparent weir is obtained. Moreover, the difference in the reactivity of the addition polymerizable unsaturated double bond between the oligomer (F) and the monomer (G) is reduced, and a homogeneous weir can be formed. It is particularly preferable that the double bond is an acryloyloxy group and the addition polymerizable unsaturated double bond of the monomer (G) is a methacryloyloxy group.

  The molecular weight of the monomer (G) is 125 to 600, preferably 140 to 400, and more preferably 150 to 350. If the molecular weight of the monomer (G) is 125 or more, volatilization of the monomer (G) when manufacturing the display device can be suppressed. If the molecular weight of a monomer (G) is 600 or less, the solubility of the monomer (G) with respect to the high molecular weight oligomer (F) can be improved, and the viscosity adjustment as a 2nd composition can be performed suitably.

The monomer (G) may contain the monomer (G1) used as a diluent in the synthesis method of the oligomer (F1). Moreover, the unreacted monomer (G2) used for the synthesis method of the oligomer (F1) may be included as the monomer (G).
Moreover, it is preferable that a monomer (G) contains a monomer (G3) from the point of the adhesiveness of a transparent surface material and a weir, and the solubility point of an additive.

Monomer (G1):
As the monomer (G1), an alkyl (meth) acrylate having an alkyl group having 8 to 22 carbon atoms (n-dodecyl (meth) acrylate, n-octadecyl (meth) acrylate, n-behenyl (meth) acrylate, etc.)), fat Examples include (meth) acrylates having a cyclic hydrocarbon group (such as isobornyl (meth) acrylate and adamantyl (meth) acrylate).

Monomer (G2):
Examples of the monomer (G2) include monomers having active hydrogen (hydroxyl group, amino group, etc.) and an addition polymerizable unsaturated double bond. Specific examples of the monomer (G2) include hydroxyalkyl (meth) acrylate (2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl) having a hydroxyalkyl group having 2 to 6 carbon atoms. (Meth) acrylate, 4-hydroxybutyl (meth) acrylate, etc.). As the monomer (G2), a hydroxyalkyl acrylate having a hydroxyalkyl group having 2 to 4 carbon atoms is preferable.

Monomer (G3):
As the monomer (G3), a hydroxy methacrylate having a hydroxyalkyl group having 1 to 2 hydroxyl groups and 3 to 8 carbon atoms (2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 4-hydroxybutyl methacrylate, 6-hydroxyhexyl) Methacrylate) and the like are preferable, and 2-hydroxybutyl methacrylate is particularly preferable.

About photopolymerization initiator (E):
Examples of the photopolymerization initiator (E) include acetophenone, ketal, benzoin, benzoin ether, phosphine oxide, benzophenone, thioxanthone, and quinone photopolymerization initiators. As the photopolymerization initiator (E), acetophenone-based, ketal-based, and benzoin ether-based photopolymerization initiators are preferable. When curing with visible light having a short wavelength, a phosphine oxide-based photopolymerization initiator is more preferable from the viewpoint of the absorption wavelength region. By using together two or more kinds of photopolymerization initiators (E) having different absorption wavelength ranges, the curing time can be further accelerated, or the surface curability at the weir can be enhanced.

About additives:
As an additive, the thing similar to what was mentioned by the 1st composition is mentioned. As an additive added to the second composition, a polymerization inhibitor and a light stabilizer are preferable. In particular, the storage stability of the second composition can be improved by including a smaller amount of the polymerization inhibitor than the polymerization initiator, and the molecular weight of the cured product of the second composition can also be adjusted.

About the mixing ratio of each raw material:
The proportion of the monomer (G) in the second composition is preferably 15 to 50% by mass, more preferably 20 to 45% by mass, out of the total (100% by mass) of the oligomer (F) and the monomer (G), 25 -40 mass% is further more preferable. When the proportion of the monomer (G) is 15% by mass or more, the curability of the second composition and the adhesion between the transparent surface material and the weir are good. If the ratio of a monomer (G) is 50 mass% or less, it will be easy to adjust the viscosity of a 2nd composition to 500 Pa.s or more.

  In addition, in the synthesis | combination of an oligomer (F1), since the monomer (G2) reacted with the isocyanate group of a prepolymer exists as a part of oligomer (F), it is not included in the ratio of a monomer (G). On the other hand, in the synthesis of the oligomer (F1), the monomer (G1) used as a diluent and the monomer (G) added after synthesizing the oligomer (F1) are included in the ratio of the monomer (G).

As for the compounding quantity of the photoinitiator (E2) in a 2nd composition, 0.01-10 mass parts is preferable with respect to a total of 100 mass parts of an oligomer (F) and a monomer (G), 0.1-5 Part by mass is more preferable.
The total amount of additives in the second composition is preferably 10 parts by mass or less and more preferably 5 parts by mass or less with respect to 100 parts by mass in total of the oligomer (F) and the monomer (G).

Regarding the viscosity of the second composition:
The viscosity of the second composition is preferably 500 to 3000 Pa · s, more preferably 800 to 2500 Pa · s, and still more preferably 1000 to 2000 Pa · s. If the viscosity of the second composition is 500 Pa · s or more, the shape of the weir before curing can be maintained for a relatively long time, and the height of the weir before curing can be sufficiently maintained. If the viscosity of the second composition is 3000 Pa · s or less, the weir before curing can be formed by coating.
In addition, even if the viscosity of the second composition is less than 500 Pa · s, when the second composition is a photocurable resin composition, by irradiating light immediately after coating, What is necessary is just to let the viscosity of a 2nd composition be the said preferable range. From the viewpoint of ease of application, the viscosity at the time of application of the second composition is preferably less than 500 Pa · s, and more preferably 200 Pa · s or less.

(Protective film)
The protective film is required not to adhere firmly to the adhesive layer. Therefore, as the protective film, a film having a relatively low adhesion to the adhesive layer, such as polyethylene, polypropylene, and fluorine resin, is preferable.

In the manufacturing method mentioned later, when bonding a protective film to a support surface material, it is calculated | required that a protective film can be bonded to a support surface material. Therefore, in this case, the protective film is preferably a self-adhesive protective film in which one surface of a base film having relatively low adhesion is an adhesive surface.
The adhesive strength of the adhesive surface of the protective film is preferably 0.01 to 0.1 N, preferably 0.02 to 0.06 N in a 50 mm wide test specimen in a 180 degree peel test at a peel rate of 300 mm / min. More preferred. If the said adhesive force is more than the said lower limit, the bonding to a support surface material is possible. If the adhesive strength is not more than the upper limit value, it is easy to peel the protective film from the support surface material.

  Although the thickness of a protective film changes with resin to be used, when using comparatively flexible films, such as polyethylene and a polypropylene, 0.04-0.2 mm is preferable and 0.06-0.1 mm is more preferable. If the thickness of a protective film is more than the said lower limit, when peeling a protective film from an adhesion layer, a deformation | transformation of a protective film can be suppressed. If the thickness of the protective film is not more than the above upper limit value, the protective film is easily bent at the time of peeling, and the protective film is easily peeled off from the adhesive layer.

[First Embodiment]
FIG. 1 is a cross-sectional view showing a first embodiment of a transparent surface material with an adhesive layer of the present invention.
The transparent surface material 1 with an adhesive layer includes a transparent surface material 10, a light shielding printing portion 12 (light shielding portion) formed on the peripheral edge of the surface of the transparent surface material 10, and a transparent surface on the side where the light shielding printing portion 12 is formed. It has a layered adhesive layer 14 formed on the surface of the material 10 and a peelable protective film 16 covering the surface of the adhesive layer 14.
A display apparatus can be manufactured by peeling the protective film 16 from the transparent surface material 1 with an adhesion layer, and bonding with the transparent surface material 1 with an adhesion layer and a display panel.

(Transparent surface material)
The transparent surface material 10 is provided on the image display surface side (that is, the viewing side) of the display panel described later to protect the display panel.

  In order to increase the contrast of the display image, the transparent surface material 10 may be provided with an antireflection layer on the surface opposite to the side on which the adhesive layer 14 is formed. Further, depending on the purpose, a part or the whole of the transparent face material 10 is colored, or a part or the whole of the surface of the transparent face material 10 is polished to form a glass to scatter light, or the surface of the transparent face material 10 is scattered. Further, a minute unevenness or the like may be formed on a part or the whole of the light to refract or reflect transmitted light. Further, a colored film, a light scattering film, a photorefractive film, a light reflecting film, or the like may be bonded to a part or the whole of the surface of the transparent surface material 10.

The shape of the transparent surface material 10 is preferably rectangular in order to match the outer shape of the display device. Depending on the outer shape of the display device, it is possible to use a transparent surface material that covers the entire display surface of the display panel and has a shape that includes a curve in the outer shape.
The size of the transparent surface material 10 may be appropriately set according to the outer shape of the display device. The thickness of the transparent surface material 10 is 0.5 to 0.5 in the case of a glass plate from the viewpoint of mechanical strength and transparency. It is preferably 25 mm. In applications such as television receivers and PC displays used indoors, 1 to 6 mm is preferable from the viewpoint of weight reduction of the display device, and 3 to 20 mm is preferable in public display applications installed outdoors. When using chemically strengthened glass, the thickness of the glass plate is preferably about 0.5 to 1.5 mm in terms of strength. In the case of a transparent resin plate, 2 to 10 mm is preferable.

(Shading printing part)
The light-shielding printing unit 12 hides wiring members and the like connected to the display panel so that areas other than the image display area of the display panel, which will be described later, are not visible from the transparent surface material 10 side. The light-shielding printing unit 12 can be formed on the surface on which the adhesive layer 14 is formed or on the opposite surface. In terms of reducing the parallax between the light-shielding printing unit 12 and the image display area, it is preferable to form the surface on the side where the adhesive layer 14 is formed. When the transparent surface material 10 is a glass plate, it is preferable to use ceramic printing containing a black pigment for the light shielding printing portion 12 because of high light shielding properties.
When the display panel wiring member or the like has a structure that cannot be seen from the side of the display panel observation, or is concealed by another member such as a housing of the display device, or a bonded object and an adhesive layer other than the display panel In the case of pasting the attached transparent face material 1, the light shielding printing portion 12 may not be formed on the transparent face material 10.

(Adhesive layer)
The adhesive layer 14 is a layer made of a transparent resin formed by curing the first composition described above.

(Protective film)
As the protective film 16, a film having a relatively low adhesiveness to the adhesive layer such as the above-described polyethylene, polypropylene, and fluorine resin is used.

[Second Embodiment]
FIG. 2 is a cross-sectional view showing a second embodiment of the transparent surface material with an adhesive layer of the present invention.
The transparent surface material 2 with the adhesive layer includes a transparent surface material 10, a light shielding printing portion 12 (light shielding portion) formed on the peripheral edge of the surface of the transparent surface material 10, and a transparent surface on the side where the light shielding printing portion 12 is formed. A layered adhesive layer 14 formed on the surface of the material 10, a frame-like weir 15 surrounding the adhesive layer 14 in contact with the periphery of the adhesive layer 14, and a peelable protective film covering the surface of the adhesive layer 14 16.
After peeling off the protective film 16 from the transparent surface material 2 with the adhesive layer, the display device can be produced by pasting the transparent surface material 2 with the adhesive layer and the display panel.
About the same structure as 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

(Weir)
The weir 15 is a portion made of a transparent resin obtained by curing the above-described second composition.

(Other embodiments)
The transparent surface material with an adhesive layer of the present invention has a transparent surface material and an adhesive layer, and the hydroxyl group concentration and the urethane bond concentration in the adhesive layer may be within a specific range. The thing is not limited.

(Mechanism of action)
In the transparent surface material with an adhesive layer of the present invention described above, the concentration of hydroxyl groups in the adhesive layer is 600 × 10 ⁻⁶ mol / g or less, and the concentration of urethane bonds in the adhesive layer is 150 ×. Since it is 10 ⁻⁶ mol / g or less, when it is bonded to an object to be bonded (display panel or the like), bubbles remaining at the interface between the object to be bonded and the adhesive layer can quickly disappear. Moreover, since the density | concentration of the hydroxyl group in an adhesion layer is 100x10 < ^-6 > mol / g or more, the adhesiveness of an adhesion layer and a transparent surface material and the adhesiveness of an adhesion layer and a to-be-bonded material are favorable. Become.

<Method for producing transparent surface material with adhesive layer>
The manufacturing method of the transparent surface material with the adhesion layer of this invention has the following process ((alpha)), the following process ((beta)), and the following process ((gamma)). This order is preferable as the order of the following process (α), the following process (β), and the following process (γ).
(Α) A step of supplying a liquid curable resin composition to the surface of the transparent surface material and partially curing the curable resin composition as necessary to obtain a partially cured product.
(Β) A step of covering the surface of the curable resin composition or the partially cured product with a protective film as necessary.
(Γ) A step of curing the curable resin composition or the partially cured product to form an adhesive layer.

  The method for producing a transparent surface material with an adhesive layer of the present invention includes a method for producing a transparent surface material with an adhesive layer not having a weir (for example, the transparent surface material with an adhesive layer of the first embodiment), and an adhesive layer having a weir. It is divided into the manufacturing method of a transparent surface material (for example, the transparent surface material with the adhesion layer of 2nd Embodiment).

[Method for producing transparent surface material with adhesive layer having no weir]
As a manufacturing method of the transparent surface material with the adhesion layer which does not have a weir, the method which has the following process ((alpha) 1), the following process ((beta) 1), and the following process ((gamma) 1) is mentioned, for example.
(Α1) A liquid adhesive layer-forming curable resin composition is supplied to the surface of the transparent surface material in a layered manner, and the adhesive layer-forming curable resin composition supplied to the surface of the transparent surface material is partially cured. Forming a layer of partially cured product.
(Β1) A step of covering the surface of the partially cured product layer with a protective film as necessary.
(Γ1) A step of further curing the partially cured product layer to form an adhesive layer.

(Process (α1))
The step (α1) may be the following step (α1a) or the following step (α1b). Supply of the adhesive layer-forming curable resin composition, a small area for installing a device necessary for curing, and the periphery of the adhesive layer-forming curable resin composition supplied to the surface of the transparent surface The step (α1a) is preferable from the viewpoint that the peripheral portion can be prevented from being thinned by spreading outward.

(Α1a) Partially curing the curable resin composition for forming an adhesive layer supplied to the surface of the transparent surface material while supplying the liquid curable resin composition for forming an adhesive layer to the surface of the transparent surface material And a step of forming a partially cured product layer.
(Α1b) A liquid adhesive layer-forming curable resin composition is supplied to the surface of the transparent surface material in layers, and after forming the adhesive layer-forming curable resin composition, the adhesive layer-forming curable resin composition A step of partially curing the layer of the product to form a layer of the partially cured product.

  Supply of the curable resin composition for forming the adhesive layer is performed using a die coater, a knife coater, or the like.

In the case of a photocurable resin composition, the curable resin composition for forming an adhesive layer is cured by irradiating ultraviolet light or short-wavelength visible light from a light source (ultraviolet lamp, high-pressure mercury lamp, UV-LED, etc.). . Light irradiation may be performed in air or may be performed under supply of nitrogen gas. The light irradiation is preferably performed from the side where the curable resin composition for forming an adhesive layer is supplied.
In the case of a thermosetting resin composition, curing of the adhesive layer forming curable resin composition is performed by heating.

  The storage shear modulus at 35 ° C. of the partially cured product layer is 1/200 to 1/5 of the storage shear modulus at 35 ° C. of the target adhesive layer. If the storage shear modulus at 35 ° C. of the partially cured product layer is equal to or higher than the lower limit, the shape of the partially cured product layer does not collapse when the protective film is stacked. If the storage shear modulus at 35 ° C. of the partially cured product layer is less than or equal to the above upper limit, the adhesion with the protective film will be sufficiently high.

(Process (β1))
In the step (β1), a protective film is overlaid on the surface of the partially cured product layer, and the surface of the partially cured product layer is covered with the protective film.
The superposition may be performed under atmospheric pressure, or may be performed under a reduced-pressure atmosphere as in the step (β2) described later.
After the overlapping, it is preferable to gradually press-bond from the end of the partially cured product layer so that the shape of the partially cured product layer does not collapse. A laminator may be used for the pressure bonding.

(Process (γ1))
In the step (γ1), the partially cured product layer is further cured to form an adhesive layer.
In the case of a photocurable resin composition, the partially cured product layer is cured by irradiating ultraviolet light or short-wavelength visible light from a light source (such as an ultraviolet lamp, a high-pressure mercury lamp, or a UV-LED). Light irradiation may be performed in air or may be performed under supply of nitrogen gas. The light irradiation is preferably performed from the protective film side.
In the case of a thermosetting resin composition, the partially cured product layer is cured by heating.

[Method for Producing Transparent Surface Material with Adhesive Layer of First Embodiment]
Hereinafter, an example of the manufacturing method of the transparent surface material 1 with the adhesion layer of 1st Embodiment is demonstrated concretely using drawing.

(Process (α1))
In the step (α1), as shown in FIGS. 3 and 4, the transparent surface material 10 placed on the transport device (not shown) is moved at a constant speed in the direction of the arrow in the drawing, The liquid first composition 18 is linearly discharged onto the surface of the transparent face material 10 from a die coater 62 arranged so that a slit (not shown) extends in a direction perpendicular to the moving direction of the material 10. At this time, both ends of the linear first composition 18 are positioned on the light-shielding printing unit 12. Along with the movement of the transparent face material 10, the first composition 18 is supplied in layers so as to cover the entire light-transmitting portion of the transparent face material 10 and the inner edge side of the light-shielding print portion 12.

  While supplying the first composition 18 in a layered manner, a line-like shape is arranged downstream of the die coater 62 in the moving direction of the transparent face material 10 so that the longitudinal direction is orthogonal to the moving direction of the transparent face material 10. The LED light source 64 is irradiated with linear light (ultraviolet light or short-wavelength visible light), and the first composition 18 supplied to the surface of the transparent surface material 10 is cured to form the partially cured material layer 20. .

(Process (β1))
In the step (β1), as shown in FIG. 5, the protective film 16 is placed on the surface of the partially cured product layer 20 under atmospheric pressure, and from the end of the partially cured product layer 20 using a laminator (not shown). The protective film 16 is gradually pressure-bonded to cover the surface of the partially cured product layer 20 with the protective film 16.

(Process (γ1))
In the step (γ1), the partially cured product layer 20 is irradiated with light (ultraviolet rays or short-wavelength visible light) from the protective film 16 side, and the partially cured product layer 20 is further cured to form the adhesive layer 14. Thereby, the transparent surface material 1 with the adhesion layer shown in FIG. 1 is obtained.

[Method for producing transparent surface material with adhesive layer having weir]
As a manufacturing method of the transparent surface material with the adhesion layer which has a weir, the method which has the following process ((alpha) 21), the following process ((alpha) 22), the following process ((beta) 2), the following process ((gamma) 21), and the following process ((gamma) 22), for example. Can be mentioned.
(Α21) A step of forming a frame-like weir at the peripheral edge of the surface of the transparent face material.
(Α22) A step of supplying the adhesive layer-forming curable resin composition to the region surrounded by the weir.
(Β2) A support surface material with a protective film is placed on the layer of the curable resin composition for forming an adhesive layer under a reduced pressure atmosphere, and the protective film is in contact with the surface of the layer of the curable resin composition for forming an adhesive layer. The process of obtaining the laminated body on which the layer of the curable resin composition for adhesion layer formation was sealed with the transparent surface material, the protective film, and the weir.
(Γ21) A step of forming an adhesive layer by curing the layer of the curable resin composition for forming an adhesive layer in a state where the laminate is placed under a higher pressure atmosphere than the step (β2).
(Γ22) A step of peeling the support surface material from the protective film after the step (γ21).

(Process (α21))
First, as a step (α21), a liquid weir-forming curable resin composition is applied to the periphery of the surface of the transparent face material to form a weir.
The application is performed using a printing machine, a dispenser, or the like. The weir may be in an uncured state or a partially cured semi-cured state. When the curable resin composition for weir formation is a photocurable composition, partial curing of the weir is performed by light irradiation. For example, the photocurable resin composition is partially cured by irradiating ultraviolet light or visible light having a short wavelength from a light source (ultraviolet lamp, high pressure mercury lamp, UV-LED, etc.).

(Process (α22))
After the step (α21), in the step (α22), a liquid adhesive layer forming curable resin composition is supplied to a region surrounded by the weir.
The supply amount of the curable resin composition for forming the adhesive layer is such that the space formed by the weir, the transparent surface material and the protective film is filled with the curable resin composition for forming the adhesive layer, and the transparent surface material and the protective film The amount is set in advance so that the interval is a predetermined interval (that is, the adhesive layer has a predetermined thickness). At this time, it is preferable to consider in advance volume reduction due to curing shrinkage of the curable resin composition for forming an adhesive layer. Therefore, the amount is preferably such that the thickness of the curable resin composition for forming an adhesive layer is slightly larger than the predetermined thickness of the adhesive layer.
Examples of the supply method include a method in which the transparent face material is placed flat and the adhesive layer-forming curable resin composition is supplied in the form of dots, lines or planes by a supply means such as a dispenser or a die coater.

(Process (β2))
After the step (α22), in the step (β2), the transparent surface material supplied with the curable resin composition for forming the adhesive layer is put into a decompression device, and the adhesive layer is formed on the fixed support disk in the decompression device. The transparent face material is laid flat so that the surface of the curable resin composition is on top.
A moving support mechanism that can move in the vertical direction is provided in the upper part of the decompression device, and a support surface material (such as a glass plate) is attached to the moving support mechanism. A protective film is bonded to the lower surface of the support surface material.
The supporting face material is placed above the transparent face material and at a position not in contact with the curable resin composition for forming the adhesive layer. That is, the curable resin composition for forming an adhesive layer on the transparent surface material and the protective film bonded to the surface of the support surface material are opposed to each other without being brought into contact with each other.

  After disposing the transparent surface material and the support surface material at predetermined positions, the inside of the pressure reducing device is depressurized to form a predetermined reduced pressure atmosphere. After the inside of the decompression device has a predetermined decompressed atmosphere, the support surface material supported by the moving support mechanism is moved downward, and the support surface material with a protective film is placed on the first composition on the transparent surface material. Are overlaid so that the surface of the protective film is in contact with the curable resin composition for forming an adhesive layer. Hereinafter, this superposition is referred to as a laminate.

By the overlapping, the adhesive layer forming curable resin composition is sealed in the surface surrounded by the surface of the transparent surface material, the surface of the protective film bonded to the support surface material, and the weir.
During the stacking, the adhesive layer-forming curable resin composition is spread by the weight of the supporting surface material, the pressure from the moving support mechanism, etc., and the space is filled with the adhesive layer-forming curable resin composition. An uncured adhesive layer is formed. Thereafter, when exposed to a high pressure atmosphere in the step (γ21), an uncured adhesive layer with few or no bubbles is formed.

  The reduced pressure atmosphere at the time of superposition is preferably 1 kPa or less, more preferably 10 to 300 Pa, and further preferably 15 to 100 Pa. If the reduced-pressure atmosphere is extremely low, each component (curable compound, photopolymerization initiator, polymerization inhibitor, chain transfer agent, light stabilizer, etc.) contained in the curable resin composition for forming an adhesive layer will be adversely affected. There is a risk of giving. For example, if the reduced-pressure atmosphere is extremely low pressure, each component may be vaporized, and it may take time to provide the reduced-pressure atmosphere.

  The time from when the transparent surface material and the support surface material are overlapped to when the reduced pressure atmosphere is released is not particularly limited, and even after the reduced pressure atmosphere is released immediately after sealing the curable resin composition for forming the adhesive layer. Alternatively, after sealing the curable resin composition for forming an adhesive layer, the reduced pressure state may be maintained for a predetermined time.

(Process (γ21))
After releasing the reduced pressure atmosphere in the step (β2), as a step (γ21), the laminate is placed in a higher pressure atmosphere than in the step (β2). As a pressure atmosphere higher than the step (β2), a pressure atmosphere of 50 kPa or more is preferable.
When the laminate is placed in a higher pressure atmosphere than in the step (β2), the pressure is increased in the direction in which the transparent surface material and the support surface material are in close contact with each other. Therefore, if bubbles exist in the sealed space in the laminate, the uncured adhesive layer flows into the bubbles, and the entire sealed space is uniformly filled with the uncured adhesive layer.

The time from when the laminate is placed in a higher pressure atmosphere than in the step (β2) to the start of curing of the uncured adhesive layer (hereinafter referred to as “high pressure holding time”) is not particularly limited. When the process from taking out the laminated body from the decompression device to the curing device and starting the curing is performed under an atmospheric pressure atmosphere, the time required for the process becomes the high pressure holding time.
Therefore, if there are no air bubbles in the sealed space of the laminate when placed in an atmospheric pressure atmosphere, or if the air bubbles disappear during the process, the uncured adhesive layer can be cured immediately. it can. When it takes time until the bubbles disappear, the laminate is held under a higher pressure atmosphere than the step (β2) until the bubbles disappear. In addition, since there is usually no problem even if the high pressure holding time is increased, the high pressure holding time may be increased due to other necessity in the process. The high-pressure holding time may be a long time of one day or longer, but is preferably within 6 hours from the viewpoint of production efficiency, more preferably within 1 hour, and particularly within 10 minutes from the viewpoint of further increasing production efficiency. preferable.

  Then, the adhesive layer and the weir are formed by curing the uncured adhesive layer and the uncured or semi-cured weir. At this time, the uncured or semi-cured weir may be cured simultaneously with the curing of the uncured adhesive layer, or may be cured in advance before the uncured adhesive layer is cured.

  When the uncured adhesive layer and the uncured or semi-cured weir are made of a photocurable composition, they are cured by irradiation with light. For example, the photocurable resin composition is cured by irradiating ultraviolet light or short wavelength visible light from a light source (ultraviolet lamp, high pressure mercury lamp, UV-LED, etc.). When a light-shielding printing part is formed on the peripheral edge of the transparent surface material, or a transparent resin film on which an antireflection layer is provided on the transparent surface material and an antireflection layer is formed, or the antireflection film and its transparent When an adhesive layer or the like provided between the face material does not transmit ultraviolet rays, light is irradiated from the support face material side.

(Process (γ22))
In the step (γ22), the support surface material is peeled off from the protective film, whereby an adhesive layer having sufficient adhesive strength is formed in advance on the transparent surface material, and bubbles are generated at the interface between the transparent surface material and the adhesive layer. A transparent surface material with an adhesive layer in which is sufficiently suppressed can be obtained.

[Method for Producing Transparent Surface Material with Adhesive Layer of Second Embodiment]
Hereinafter, an example of the manufacturing method of the transparent surface material 2 with the adhesion layer of 2nd Embodiment is demonstrated concretely using drawing. In this production, the following steps α21, α22, β2, γ21, and γ22 are performed in this order.

(Process (α21))
As shown in FIGS. 6 and 7, the second composition is applied by a dispenser (not shown) or the like along the light shielding printing portion 12 at the peripheral edge of the transparent face material 10 to form an uncured weir 22.

(Process (α22))
Next, as shown in FIGS. 8 and 9, the first composition 26 is supplied to a rectangular region 24 surrounded by the uncured weir 22 of the transparent surface material 10. The supply amount of the first composition 26 is set in advance so that the space sealed by the uncured weir 22, the transparent face material 10, and the protective film 16 (see FIG. 10) is filled with the first composition 26. Is set.

As shown in FIG. 8 and FIG. 9, the first composition 26 is supplied by placing the transparent surface material 10 flat on the lower platen 28 and moving the first composition 26 into a linear or belt shape by a dispenser 30 that moves in the horizontal direction. Or it implements by supplying in a dot form.
The dispenser 30 is horizontally movable in the entire range of the region 24 by a known horizontal movement mechanism including a pair of feed screws 32 and a feed screw 34 orthogonal to the feed screw 32. Instead of the dispenser 30, a die coater may be used.

(Process (β2))
Next, as shown in FIG. 10, the transparent surface material 10 and the support surface material 36 with the protective film 16 are carried into the decompression device 38. An upper surface plate 42 having a plurality of suction pads 40 is disposed in the upper portion of the decompression device 38, and a lower surface plate 44 is disposed in the lower portion. The upper surface plate 42 can be moved in the vertical direction by an air cylinder 46.
The support surface material 36 is attached to the suction pad 40 with the surface to which the protective film 16 is bonded facing down. The transparent surface material 10 is fixed on the lower surface plate 44 with the surface to which the first composition 26 is supplied facing up.

  Next, the air in the decompression device 38 is sucked by the vacuum pump 48. After the atmospheric pressure in the pressure reducing device 38 reaches a reduced pressure atmosphere of, for example, 15 to 100 Pa, the transparent surface material waiting below in a state where the support surface material 36 is adsorbed and held by the adsorption pad 40 of the upper surface plate 42. 10, the air cylinder 46 is operated and lowered. And the transparent surface material 10 and the support surface material 36 with the protective film 16 are piled up through the uncured weir 22. Thus, the transparent body 10, the protective film 16, and the uncured weir 22 constitute a laminated body in which the uncured adhesive layer made of the first composition 26 is sealed, and the laminated body is formed for a predetermined time in a reduced-pressure atmosphere. Hold.

(Process (γ21))
Next, after making the inside of the decompression device 38 into an atmospheric pressure atmosphere, for example, the laminate is taken out from the decompression device 38. When the laminate is placed in an atmospheric pressure atmosphere, the surface of the laminate on the transparent face material 10 side and the surface on the support face material 36 side are pressed by atmospheric pressure, and the uncured adhesive layer in the sealed space becomes a transparent face material. 10 and the support surface material 36 are pressurized. By this pressure, the uncured adhesive layer in the sealed space flows, and the entire sealed space is uniformly filled with the uncured adhesive layer.

  Next, the uncured weir 22 and the uncured adhesive layer are irradiated with light (ultraviolet rays and visible light having a short wavelength) from the support surface material 36 side, and the uncured weir 22 and the uncured adhesive layer inside the laminate are then irradiated. Is cured to form the adhesive layer 14 and the weir 15.

(Process (γ22))
Subsequently, the support surface material 36 is peeled from the protective film 16 to obtain the transparent surface material 2 with the adhesive layer shown in FIG.

(Other embodiments)
The method for producing a transparent surface material with an adhesive layer of the present invention is a method for producing the transparent surface material with an adhesive layer of the present invention, as long as it is a method having a step (α) and a step (γ). It is not limited to the manufacturing method of the transparent surface material with an adhesion layer.
For example, the peripheral edge portion of the protective film of the transparent surface material with the adhesive layer may be airtightly bonded to the transparent surface material over the entire circumference under reduced pressure conditions. Specifically, the peripheral portion of the protective film 16 of the transparent surface material 1 with the adhesive layer shown in FIG. 1 is placed at any position (side surface, lower surface, upper surface, etc.) of the transparent surface material 10 over the entire circumference under reduced pressure conditions. May be joined airtightly. As a result, the adhesive layer 14 is hermetically wrapped in the protective film 16, so it is possible to reliably prevent outside air from being mixed into the adhesive layer 14.
Moreover, you may enclose the transparent surface material with an adhesion layer in the enclosure which consists of a film which has gas barrier property on pressure reduction conditions. Thereby, it is possible to prevent the outside air from being mixed into the adhesive layer.

(Mechanism of action)
In the method for producing a transparent surface material with an adhesive layer of the present invention described above, the method for producing the transparent surface material with an adhesive layer of the present invention, comprising the step (α) and the step (γ), When bonded to the object to be bonded, it is possible to produce a transparent surface material with an adhesive layer in which bubbles remaining at the interface between the object to be bonded and the adhesive layer can quickly disappear.

<Display device>
FIG. 11 is a cross-sectional view illustrating an example of the display device of the present invention.
The display device 3 includes the display panel 50 and the transparent surface material 2 with the adhesive layer bonded to the display panel 50 so that the adhesive layer 14 contacts the display panel 50.
The display device 3 is connected to the transparent surface material 10, the display panel 50, the adhesive layer 14 sandwiched between the transparent surface material 10 and the display panel 50, the weir 15 surrounding the adhesive layer 14, and the display panel 50. And a flexible printed wiring board 60 (FPC) on which a driving IC for operating the display panel 50 is mounted.

(Display panel)
As shown in FIG. 11, in the display panel 50, a transparent substrate 52 provided with a color filter and a transparent substrate 54 provided with a TFT are bonded with a liquid crystal layer 56 interposed therebetween, and this is sandwiched between a pair of polarizing plates 58. It is an example of the liquid crystal panel of a structure.

In order to improve adhesiveness with the adhesion layer 14, you may surface-treat to the joint surface with the adhesion layer 14 of the display panel 50. FIG. The surface treatment may be performed only on the peripheral edge or on the entire surface of the face material. Examples of the surface treatment method include a treatment method using an adhesion primer or the like which can be processed at a low temperature.
The thickness of the display panel 50 is about 0.4 to 4 mm in the case of a liquid crystal panel operated by a TFT, and is often about 0.2 to 3 mm in the case of an EL panel.

(shape)
The shape of the display panel 50 is generally a rectangle. The dimensions of the transparent surface material 10 and the display panel 50 may be substantially equal, or the transparent surface material 10 may be made slightly larger than the display panel 50 in view of the relationship with the other housing that houses the display device. Conversely, the transparent surface material 10 may be slightly smaller than the display panel 50 depending on the structure of another casing.

(Other embodiments)
The display apparatus of this invention should just be what the transparent surface material with the adhesion layer of this invention was bonded by the display panel, and is not limited to the thing of the example of illustration.
For example, the display panel is not limited to the liquid crystal panel shown in FIG.
The display panel changes in optical characteristics by an external electric signal between a pair of electrodes, at least one of which is a transparent electrode, or between a substrate having a plurality of electrode pairs formed in the same plane and a transparent substrate. The display material is sandwiched. There are liquid crystal panels, EL panels, plasma panels, electronic ink panels, and the like depending on the type of display material.
Further, the display panel has a structure in which a pair of face materials, at least one of which is a transparent substrate, is bonded, and is arranged so that the transparent substrate side is in contact with the adhesive layer. At this time, in some display panels, an optical film such as a polarizing plate or a retardation plate may be provided on the outermost layer side of the transparent substrate on the side in contact with the adhesive layer. In this case, the adhesive layer is in a state of joining the optical film on the display panel and the transparent surface material.

(Mechanism of action)
In the display device of the present invention described above, since the transparent surface material with the adhesive layer of the present invention is bonded to the display panel, the remaining of bubbles at the interface between the display panel and the adhesive layer is suppressed. It will be

<Manufacturing method of display device>
In order to manufacture the display device of the present invention, the protective film (protective material) is peeled from the transparent surface material with the adhesive layer of the present invention, and then the display panel and the transparent surface material with the adhesive layer are bonded to the display panel. Laminate to touch.
The manufacturing method of the display device may be a method including steps S1 and S2 described below.

(Step S1: Protective film peeling step)
In this step, the protective film is peeled from the transparent surface material with the adhesive layer, which is covered with the protective film. The protective film may be peeled in the air or in a reduced pressure atmosphere. After the protective film is peeled off, the transparent surface material with the adhesive layer can be stored in a reduced pressure atmosphere without being exposed to the atmosphere until the transparent surface material with the adhesive layer is transferred to the inside of the vacuum container used in the step S2. If it exists, it is preferable to carry out peeling of the protective film under a reduced pressure atmosphere.
However, it is often difficult to actually remove the protective film in a reduced pressure atmosphere due to production facilities and the like. In that case, there is no particular problem even if the protective film is peeled off in the air. It is preferable to carry out the peeling of the protective film in the air in that it is not necessary to prepare a vacuum container for the protective film peeling step. After the protective film is peeled off, it is preferable to immediately perform the next step S2.

(Process S2: Pasting process)
In this process, in the bonding apparatus, the display panel and the transparent surface material with the adhesive layer are bonded together in a state where the adhesive layer is in contact with the display panel. At this time, in the decompression container of the pasting device, it is preferable to paste the display panel and the transparent surface material with the adhesive layer in a reduced pressure atmosphere. By performing bonding in a reduced pressure atmosphere, bubbles are less likely to be generated at the interface between the display panel and the adhesive layer. Inside the decompression vessel, after maintaining the decompressed atmosphere for a predetermined time, the decompressed atmosphere is released to normal pressure.
20 kPa or less is preferable, the pressure reduction atmosphere in the case of bonding is more preferable, 15-0.5 kPa is more preferable, and 10-0.2 kPa is further more preferable. If the degree of decompression is less than or equal to the above upper limit, bubbles are unlikely to remain, and if the degree of decompression is greater than or equal to the lower limit, a large decompression device is not required.

From the point of production efficiency, it is preferable that the time from when the display panel and the transparent surface material with the adhesive layer are overlapped to when the reduced pressure atmosphere is released is short. For example, it is preferably within 1 minute, and more preferably within 10 seconds.
After bonding the display panel and the transparent face with adhesive layer, the adhesive layer that is not fully cured is irradiated with light again or heated to accelerate the curing of the adhesive layer, and the adhesive layer is cured. May be stabilized.

  When the transparent surface material with the adhesive layer has flexibility, the transparent surface material with the adhesive layer is curved so that the surface side on which the adhesive layer is formed of the transparent surface material with the adhesive layer is convex, and the adhesive layer The attached transparent surface material may be bonded by a method of gradually overlapping the display panel from one end side to the other end side. According to this method, since the gas existing in the space between the transparent surface material with the adhesive layer and the display panel is pushed out from one end side to the other end side, the bonding is performed, so the interface between the display panel and the adhesive layer Air bubbles are less likely to be generated.

(Mechanism of action)
As shown in FIG. 12, immediately after bonding the transparent surface material 2 with the adhesive layer and the display panel 50, bubbles M1 and M2, which are sealed spaces, are formed at the interface between the display panel 50 and the adhesive layer 14. Although it may occur, most of the bubbles M1 and M2 generated immediately after bonding disappear after a predetermined time.
The present inventors inferred the mechanism of disappearance of bubbles generated immediately after bonding as follows. Three processes of P1, P2, and P3 can be considered as the process of reducing the volume of the bubbles.

(Process P1: Volume reduction by bonding differential pressure)
In the process P1, after the display panel and the transparent surface material with the adhesive layer are bonded in a reduced pressure atmosphere, when the pressure is returned to the normal pressure atmosphere, the pressure inside the bubbles in the reduced pressure state and the adhesive layer from the outside This is a process in which a differential pressure from the applied pressure (that is, the atmospheric pressure when returned to the atmospheric pressure atmosphere) is generated, and the volume of the bubbles is reduced by this differential pressure. The period of the process P1 is, for example, about several seconds. That is, the volume of the bubble is rapidly reduced after a few seconds from the time when the pressure is returned to the atmospheric pressure.

(Process P2: Volume reduction by absorption of gas in bubbles into the adhesive layer)
Process P2 is a process in which the volume of bubbles is reduced by the gas confined in the bubbles being absorbed and dissolved in the adhesive layer in contact with the bubbles. The period of the process P2 is, for example, about several minutes to several tens of minutes. The rate of bubble volume reduction in process P2 is slower than the rate of bubble volume reduction in process P1.

(Process P3: Volume reduction due to gas diffusion in the adhesive layer)
In the process P3, as the gas dissolved in the adhesive layer in the process P2 diffuses from the periphery of the bubble to the outside thereof, the gas in the bubble is reabsorbed by the adhesive layer in contact with the bubble and is dissolved again. This is a process of decreasing the volume of the.
That is, the gas concentration remaining in the bubbles after the process P2 and the gas concentration dissolved in the adhesive layer around the bubbles are almost in equilibrium. However, this time, since the gas concentration dissolved in the adhesive layer around the bubble and the gas concentration in the adhesive layer located away from the bubble are in a non-equilibrium state, the gas dissolved in the adhesive layer is further increased from the periphery of the bubble. It spreads outside.
Through this process, the gas in the bubbles is reabsorbed and re-dissolved in the adhesive layer in contact with the bubbles. The period of the process P3 is, for example, several hours or more. The speed of the bubble volume reduction in the process P3 depends on the diffusion rate of the gas in the adhesive layer, and is therefore slower than the speed of the bubble volume reduction in the process P2. The bubbles disappear almost completely through the process P3.

As described above, immediately after the transparent surface material 2 with the adhesive layer 2 and the display panel 50 are bonded together, bubbles (M1 and M2 in FIG. 12) are generated at the interface between the display panel 50 and the adhesive layer 14.
As a result of the study by the present inventors, it has been found that the conventional transparent surface material with an adhesive layer tends to require a long time for the disappearance of bubbles when stored for a long time after production. According to the attached transparent face material, the bubbles disappear in a short time even when used for pasting with an object to be pasted after a long period of time has passed since the manufacture.

The reason why the bubbles disappear in a short time when the transparent surface material with an adhesive layer of the present invention is used can be inferred as follows.
As described above, in the transparent face material with an adhesive layer of the present invention, the concentration of hydroxyl groups in the adhesive layer is 600 × 10 ⁻⁶ mol / g or less, and the concentration of urethane bonds in the adhesive layer is 150 × 10 6. ^-6 mol / g or less. Therefore, the pressure-sensitive adhesive layer has a weak cohesive force and facilitates gas diffusion into the pressure-sensitive adhesive layer. As a result, the processes P2 and P3 are accelerated, and as a result, the remaining bubbles disappear in a short time.

(Other embodiments)
The manufacturing method of the display device of the present invention is a method of manufacturing the display device of the present invention, wherein the display panel and the transparent surface material with the adhesive layer are brought into contact with the display panel in a reduced pressure atmosphere. Any method can be used as long as it is laminated and bonded, and the production method described above is not limited.
For example, in the manufacturing method described above, the gas content of the adhesive layer is reduced by placing the adhesive layer under reduced pressure conditions in the manufacturing process of the transparent face material with the adhesive layer of the second embodiment. As long as it is before the process of bonding the transparent surface material with an adhesion layer to a to-be-bonded thing, the process by which the gas content of the adhesion layer decreases may be any time.

Various modifications can be made without departing from the spirit of the present invention.
For example, the transparent surface material with an adhesive layer may be bonded to a coordinate input device such as a touch panel.
The transparent surface material may be a substrate with a transparent electrode that constitutes a touch panel portion in a display device with a touch panel. An adhesive layer can also be formed on both surfaces of a substrate with a transparent electrode, and a transparent surface material and a display panel can be bonded via a substrate with a transparent electrode having an adhesive layer formed on both surfaces.

<Adhesive sheet>
The pressure-sensitive adhesive sheet of the present invention comprises a cured product of a curable resin composition for forming a pressure-sensitive adhesive sheet.
The pressure-sensitive adhesive sheet of the present invention may be a pressure-sensitive adhesive sheet with a protective film further having a peelable protective film on one surface or both surfaces of the pressure-sensitive adhesive sheet, if necessary.

  The pressure-sensitive adhesive sheet is obtained by allowing the pressure-sensitive adhesive layer in the above-mentioned transparent surface material with a pressure-sensitive adhesive layer to exist alone without a transparent surface material. Therefore, the characteristics and material of the pressure-sensitive adhesive sheet, and preferred embodiments are the same as those of the pressure-sensitive adhesive layer described above, and detailed description thereof is omitted.

  An adhesive sheet can be manufactured by the manufacturing method similar to the manufacturing method of the transparent surface material with an adhesion layer by using a protective film or a support surface material with a protective film instead of a transparent surface material, for example.

In the pressure-sensitive adhesive sheet of the present invention described above, the concentration of hydroxyl groups in the pressure-sensitive adhesive sheet layer is 600 × 10 ⁻⁶ mol / g or less, and the concentration of urethane bonds in the pressure-sensitive adhesive sheet is 150 × 10 ^−6. Since it is mol / g or less, when it bonds with a to-be-bonded object (transparent surface material, a display panel, etc.), the bubble which remain | survives in the interface of a to-be-bonded object and an adhesive sheet can lose | disappear rapidly. Moreover, since the density | concentration of the hydroxyl group in an adhesive sheet is 100 * 10 < ^-6 > mol / g or more, the adhesiveness of an adhesive sheet and a to-be-bonded material (for example, a transparent surface material, a display panel, etc.) becomes favorable. .

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.
Examples 1, 2, 4, and 5 are examples, and examples 3 and 6 are comparative examples.
The transparent surface material, the object to be bonded, the support surface material with a protective film, the curable oligomer (A), the non-curable oligomer (C), the first composition, and the second composition in each example are prepared as follows. It is a thing.

(Transparent surface material)
Transparent face material (1):
Printed with ink containing a black pigment so that the translucent portion is 218 mm long and 168 mm wide at the periphery of one surface of a soda-lime glass plate having a length of 240 mm, a width of 190 mm, and a thickness of 1.3 mm A light shielding printing part was formed in a shape to produce a transparent surface material (1).

Transparent face material (2):
Printed with ink containing a black pigment so that the translucent portion is 85 mm long and 85 mm wide on one surface of a soda lime glass plate having a length of 100 mm, a width of 100 mm, and a thickness of 1.3 mm A light shielding printing part was formed in a shape to produce a transparent surface material (2).

(To be bonded)
Article to be bonded (1):
Adhering a polarizing plate with an adhesive layer (KN-18240T, manufactured by Polatechno Co., Ltd.) on one surface of a soda lime glass plate having a length of 220 mm, a width of 170 mm, and a thickness of 1.1 mm, and substituting a liquid crystal panel Compound (1) was obtained.

Article to be bonded (2):
Adhesive layered polarizing plate (KN-18240T, manufactured by Polatechno Co., Ltd.) is bonded to one surface of a soda lime glass plate having a length of 90 mm, a width of 90 mm, and a thickness of 2 mm. It was set as thing (2).

(Support surface with protective film)
A protective film (manufactured by Mitsui Chemicals Tosero Co., Ltd., Puretect) on one side of a support surface material made of a soda-lime glass plate having a length of 100 mm, a width of 100 mm, and a thickness of 2 mm. (Registered trademark) VLH-9) was bonded using a rubber roll so that the adhesive surface of the protective film was in contact with the glass, and a support surface material with a protective film was produced.

(Curable oligomer (A))
UA-1:
Bifunctional polypropylene glycol (number average molecular weight calculated from hydroxyl value: 18000) and isophorone diisocyanate are mixed at a molar ratio of 4 to 5, and obtained by reacting at 70 ° C. in the presence of a tin compound catalyst. 2-hydroxyethyl acrylate was added to the resulting prepolymer at a molar ratio of approximately 1 to 2 of the prepolymer and 2-hydroxyethyl acrylate, and reacted at 70 ° C. to obtain a urethane acrylate oligomer (hereinafter referred to as UA-). 1)).
The average number of addition polymerizable unsaturated double bonds of UA-1 was 2, the number average molecular weight was about 73,000, and the viscosity at 25 ° C. was about 250 Pa · s.

UA-2:
A urethane acrylate oligomer (hereinafter referred to as UA-2) was obtained in the same manner as UA-1, except that bifunctional polypropylene glycol (number average molecular weight calculated from hydroxyl value: 10,000) was used.
The average number of addition polymerizable unsaturated double bonds of UA-2 was 2, the number average molecular weight was about 41000, and the viscosity at 25 ° C. was about 250 Pa · s.

UA-3:
A urethane acrylate oligomer (hereinafter referred to as UA-3) is represented by the same method as UA-1, except that bifunctional polypropylene glycol having a molecular terminal modified with ethylene oxide (number average molecular weight calculated from hydroxyl value: 4000) is used. )
The average number of addition polymerizable unsaturated double bonds of UA-3 was 2, the number average molecular weight was about 17,300, and the viscosity at 25 ° C. was about 250 Pa · s.

UA-4:
Bifunctional polypropylene glycol whose molecular terminal is modified with ethylene oxide (number average molecular weight calculated from hydroxyl value: 4000) and hexamethylene diisocyanate are mixed at a molar ratio of 6: 7, and then isobornyl acrylate (Osaka Organic Chemical Industry) After dilution with IBXA, a prepolymer was obtained by reaction at 70 ° C. in the presence of a tin catalyst. To the obtained prepolymer, 2-hydroxyethyl acrylate was added so that the molar ratio of the prepolymer and 2-hydroxyethyl acrylate was 1: 2, reacted at 70 ° C., and diluted with 30% by mass of isobornyl acrylate. The obtained urethane acrylate oligomer (UA-4) (hereinafter referred to as UA-4) was obtained.
The average number of addition polymerizable unsaturated double bonds of UA-4 was 2, the number average molecular weight was 55000, and the viscosity at 60 ° C. was 580 Pa · s.

UA-5:
Monofunctional polypropylene glycol (number average molecular weight calculated from hydroxyl value: 10,000) and 2-acryloyloxyethyl isocyanate are mixed at a molar ratio of 1: 1, and in the presence of a tin compound catalyst, 70 ° C. To obtain a urethane acrylate oligomer (hereinafter referred to as UA-5).
The average number of addition polymerizable unsaturated double bonds of UA-5 was 1, the number average molecular weight was about 10100, and the viscosity at 25 ° C. was about 7 Pa · s.

UA-6:
A urethane acrylate oligomer (hereinafter referred to as UA-6) was obtained in the same manner as UA-3 except that monofunctional polypropylene glycol (number average molecular weight calculated from hydroxyl value: 5000) was used.
The number of curable groups of UA-6 was 1, the number average molecular weight was about 5100, and the viscosity at 25 ° C. was about 3 Pa · s.

(Non-curable oligomer (C))
Non-curable oligomer (1):
Bifunctional polypropylene glycol modified with ethylene oxide at the molecular end (number average molecular weight calculated from hydroxyl value: 4000) and trifunctional polypropylene glycol modified at molecular end with ethylene oxide (number average molecular weight calculated from hydroxyl value: 6200) The mixture was mixed at a mass ratio of 1: 1 to obtain a non-curable oligomer (1).

(First composition)
First composition (1):
(A) 20 mass parts of UA-1 as a component, 32.5 mass parts of UA-5, and 32.5 mass parts of UA-6, (B) Phenylglycidyl ether acrylate (manufactured by Kyoeisha Chemical Co., Ltd., epoxy) 15 parts by mass of ester M-600A) were uniformly mixed, and then 100 parts by mass of the mixture was mixed with bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (manufactured by BASF) as component (D). , IRGACURE (registered trademark) 819), 0.34 parts by mass of 2,5-di-tert-butylhydroquinone (polymerization inhibitor, manufactured by Tokyo Chemical Industry Co., Ltd.), and antioxidant (manufactured by BASF) , PUR 68) is uniformly dissolved and mixed, and then 100 parts by mass of the mixture is mixed with terminally methylated polypropylene glycol as component (C). Lumpur (number average molecular weight calculated from the hydroxyl value: 1200) homogeneously dissolved 42.9 parts by weight of the mixed, to obtain a first composition (1).
The viscosity at 25 ° C. of the first composition (1) was 3.2 Pa · s. The concentration of hydroxyl groups in the first composition (1) is 471 × 10 ⁻⁶ mol / g, the concentration of urethane bonds is 85 × 10 ⁻⁶ mol / g, and the sum of the concentration of hydroxyl groups and the concentration of urethane bonds is 556 * 10 < ^-6 > mol / g, SP value was 18.2 (J / cm < ³ >) < ^1/2 >. Since the hydroxyl group and the urethane bond do not react during curing, the concentration of the hydroxyl group after curing and the concentration of the urethane bond do not change.
In addition, the method of calculating | requiring the density | concentration of a hydroxyl group calculated | required by calculating the molar concentration of the hydroxyl group contained in (A), (B), (C) component. Specifically, in the first composition (1), the phenyl glycidyl ether acrylate of the component (B) has a hydroxyl group, and the concentration of the hydroxyl group is 0.0045 mol / g. When (A), (B), and (C) component are mixed by the said compounding quantity and it calculates as a density | concentration of the hydroxyl group contained in (A), (B), (C) component, it is 471 * 10 < ^-6 > mol /. g.
The urethane bond concentration was determined by calculating the molar concentration of the urethane bond contained in the components (A), (B), and (C). Specifically, in the first composition (1), UA-1, UA-5, and UA-6 of the component (A) contain a urethane bond, and the molar concentration thereof is 19 × 10 9 respectively. ^-6 mol / g, 44 × 10 ⁻⁶ mol / g, and 22 × 10 ⁻⁶ mol / g. When (A), (B), and (C) component are mixed by the said compounding quantity and it calculates as a density | concentration of the urethane bond contained in (A), (B), (C) component, it will be 85 * 10 < ^-6 > mol. / G.

First composition (2):
(A) 20 mass parts of UA-2, 32.5 mass parts of UA-5, and 32.5 mass parts of UA-6 as component (A) Phenyl glycidyl ether acrylate (manufactured by Kyoeisha Chemical Co., epoxy) 15 parts by weight of the ester M-600A) were uniformly mixed, and then 3 parts by weight of 1-hydroxy-cyclohexyl-phenyl-ketone (manufactured by BASF, IRGACURE® 184) was added to 100 parts by weight of the mixture. , 0.04 parts by mass of 2,5-di-tert-butylhydroquinone (polymerization inhibitor, manufactured by Tokyo Chemical Industry Co., Ltd.) and 1 part by mass of an antioxidant (manufactured by BASF, PUR 68) After mixing, 100 parts by mass of the mixture was terminal methylated as component (C) polypropylene glycol (number average molecular weight calculated from hydroxyl value: 1 00) was uniformly dissolved 66.7 parts by weight of the mixed, to obtain a first composition (2).
The viscosity at 25 ° C. of the first composition (2) was 1.5 Pa · s. The concentration of hydroxyl groups in the first composition (2) is 398 × 10 ⁻⁶ mol / g, the concentration of urethane bonds is 85 × 10 ⁻⁶ mol / g, and the total of the concentration of hydroxyl groups and the concentration of urethane bonds is 483 × 10 ⁻⁶ mol / g, and the SP value was 18.2 (J / cm ³ ) ^1/2 . Since the hydroxyl group and the urethane bond do not react at the time of curing, the concentration of the hydroxyl group after curing and the concentration of the urethane bond do not change.

First composition (3):
(A) 25.7 parts by mass of polyisoprene methacrylate (manufactured by Kuraray Co., Ltd., UC203) as component (A), 7.7 parts by mass of dicyclopentenyloxyethyl methacrylate as component (B), 2.6 masses of 2-hydroxypropyl acrylate Parts, 54.1 parts by mass of polybutadiene (Evonik Degussa, Polyoil 110) as component (C), 1-hydroxy-cyclohexyl-phenyl-ketone (IRSFACURE (registered trademark) 184, manufactured by BASF) as component (D) 1 part by weight and 0.4 part by weight of 2,4,6-trimethylbenzoyldiphenylphosphine oxide (manufactured by LAMBSON, Speed Cure TPO) were uniformly mixed to obtain a first composition (3). .
The viscosity at 25 ° C. of the first composition (3) was 2.5 Pa · s. The concentration of the hydroxyl groups of the first composition (3) in ^{the, 220 × 10 -6 mol / g} , the concentration of urethane bond, the sum of 0 mol / g, the concentration and the concentration of urethane linkages hydroxyl, 220 × 10 ^{- The 6} mol / g and SP values were 18.0 (J / cm ³ ) ^1/2 . Since the hydroxyl group does not react during curing, the concentration of the hydroxyl group after curing does not change.

First composition (4):
(A) 40 parts by mass of UA-3 as component, 40 parts by mass of 2-hydroxybutyl methacrylate (manufactured by Kyoeisha Chemical Co., light ester HOB) and 20 parts by mass of n-dodecyl methacrylate as component (B) are uniformly mixed. In addition, to 100 parts by mass of the mixture, 0.5 part by mass of bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (manufactured by BASF, IRGACURE (registered trademark) 819) as component (D), 0.04 part by mass of 2,5-di-tert-butylhydroquinone (polymerization inhibitor, manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.3 part by mass of an antioxidant (manufactured by BASF, IRGANOX (registered trademark) 1010) It was dissolved uniformly. Thereafter, 42.9 parts by mass of the non-curable oligomer (1) as the component (C) were uniformly dissolved and mixed in 100 parts by mass of the mixture to obtain a first composition (4).
The viscosity at 25 ° C. of the first composition (4) was 3.0 Pa · s. The concentration of hydroxyl groups in the first composition (4) is 1925 × 10 ⁻⁶ mol / g, the concentration of urethane bonds is 161 × 10 ⁻⁶ mol / g, and the sum of the concentration of hydroxyl groups and the concentration of urethane bonds is 2086 × 10 ⁻⁶ mol / g, and the SP value was 20.3 (J / cm ³ ) ^1/2 . Since the hydroxyl group and the urethane bond do not react at the time of curing, the concentration of the hydroxyl group after curing and the concentration of the urethane bond do not change.

First composition (5):
50 parts by mass of UA-4 as component (A) and 50 parts by mass of 4-hydroxybutyl acrylate as component (B) are uniformly mixed, and 100 parts by mass of the mixture is mixed with 1-hydroxy- as component (D). 3 parts by mass of cyclohexyl-phenyl-ketone (manufactured by BASF, IRGACURE (registered trademark) 184), 0.04 parts by mass of 2,5-di-tert-butylhydroquinone (polymerization inhibitor, manufactured by Tokyo Chemical Industry Co., Ltd.), and One part by mass of an antioxidant (manufactured by BASF, PUR 68) was uniformly dissolved. Thereafter, 150 parts by mass of the non-curable oligomer (1) as component (C) was uniformly dissolved and mixed in 100 parts by mass of the mixture to obtain a first composition (5).
The viscosity at 25 ° C. of the first composition (5) was 5.9 Pa · s. The concentration of hydroxyl groups in the first composition (5) is 1850 × 10 ⁻⁶ mol / g, the concentration of urethane bonds is 74 × 10 ⁻⁶ mol / g, and the sum of the concentration of hydroxyl groups and the concentration of urethane bonds is 1924 × 10 ⁻⁶ mol / g, and the SP value was 19.6 (J / cm ³ ) ^1/2 . Since the hydroxyl group and the urethane bond do not react at the time of curing, the concentration of the hydroxyl group after curing and the concentration of the urethane bond do not change.

(Second composition)
Second composition (1):
As a component (F), 55 parts by mass of UA-4 and as a component (G) 45 parts by mass of 4-hydroxybutyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., 4HBA) were uniformly mixed to obtain a mixture. To 100 parts by mass of the mixture, 3.0 parts by mass of 1-hydroxy-cyclohexyl-phenyl-ketone (manufactured by BASF, IRGACURE (registered trademark) 184) as component (E), bis (2,4,6-trimethyl) 0.5 part by mass of benzoyl) -phenylphosphine oxide (manufactured by BASF, IRGACURE (registered trademark) 819), 0.04 of 2,5-di-tert-butylhydroquinone (polymerization inhibitor, manufactured by Tokyo Chemical Industry Co., Ltd.) A base composition was obtained by uniformly mixing 0.3 parts by mass of an antioxidant and an antioxidant (IRGANOX (registered trademark) 1010, manufactured by BASF). 25 parts by mass of the non-curable oligomer (1) was uniformly dissolved in 75 parts by mass of the base composition to obtain a second composition (1). The viscosity at 25 ° C. of the second composition (1) was 60 Pa · s.

(Example 1)
Production of transparent face material (1) with adhesive layer:
Using a die coater, the first composition (1) is uniformly applied to the surface of the transparent surface material (1) moving at a constant speed with a thickness of 400 μm, and UV light is emitted from an LED light source disposed downstream of the die coater. Was irradiated to form a partially cured product layer.
A protective film larger than the transparent face material (1) (Puretect (registered trademark) VLH-9, manufactured by Mitsui Chemicals, Inc.) was laminated on the surface of the partially cured product layer.
Adhesion protected by a protective film by irradiating ultraviolet rays from a high-pressure mercury light source (USHIO ELECTRIC CO., LTD., UVC-05016S1TA01, irradiation intensity: 100 mW / cm ² ) placed on the protective film side to completely cure the partially cured product layer A transparent face material (1) with a layer was obtained.
The irradiation intensity was measured using an illuminometer (manufactured by Ushio Electric Co., Ltd., UV intensity meter Unimeter UIT-101).
In Example 1, the storage shear modulus at 35 ° C. of the partially cured product layer is 700 Pa, and the storage shear modulus at 35 ° C. of the adhesive layer is 5300 Pa.

(Example 2)
Production of transparent face material (2) with adhesive layer:
Except having used the 1st composition (2) instead of the 1st composition (1), it carried out similarly to Example 1, and obtained the transparent surface material (2) with the adhesion layer protected by the protective film.
In Example 2, the storage shear modulus at 35 ° C. of the partially cured product layer is 60 Pa, and the storage shear modulus at 35 ° C. of the adhesive layer is 3000 Pa.

(Example 3)
Production of transparent face material with adhesive layer (3):
A transparent surface material with an adhesive layer (3) protected by a protective film was obtained in the same manner as in Example 1 except that the first composition (5) was used instead of the first composition (1).
In Example 3, the storage shear modulus at 35 ° C. of the partially cured product layer is 900 Pa, and the storage shear modulus at 35 ° C. of the adhesive layer is 4600 Pa.

(Bubble disappearance test 1)
The protective film was peeled off from the transparent surface material (1) with an adhesive layer under normal pressure. Place the adhesive pad and electrostatic chuck on the upper surface plate in the decompression device where the lifting device for the pair of surface plates is installed so that the surface of the adhesive layer faces downward. Used and held.
The polarizing plate bonded to the object to be bonded (1) on the lower surface plate of the lifting device in the decompression device with the object to be bonded (1) and the adhesive layer of the transparent surface material with an adhesive layer (1) Opposing, arrange | positioning so that the center location of a transparent surface material (1) with an adhesion layer and a polarizing plate may correspond, and it hold | maintained so that the distance with a transparent surface material (1) with an adhesion layer might be set to 30 mm.
The decompression device was sealed and evacuated until the pressure in the decompression device reached about 100 Pa, and held for 10 minutes. Next, the pressure was returned to normal pressure and held for 1 minute. Next, after exhausting until the pressure in the decompression device reaches about 10 Pa and holding for 1 minute, the upper and lower surface plates are brought close to each other by the lifting device in the decompression device, and the polarized light pasted on the object to be bonded (1). The plate and the transparent face material (1) with the adhesive layer were pressure-bonded with a pressure of 2 kPa through the adhesive layer and held for 10 seconds. The electrostatic chuck was neutralized and the object to be bonded (1) was separated from the upper surface plate, and the inside of the decompression device was returned to atmospheric pressure in about 20 seconds to obtain a simulated display device.
When the simulated display device was observed immediately after being laminated with the transparent surface material with adhesive layer (1), the polarizing plate bonded to the object to be bonded (1) and the adhesive layer of the transparent surface material with adhesive layer (1) Many fine bubbles were seen at the interface. The simulated display device was allowed to stand, and the time until bubbles disappeared (bubble disappearance time) was measured. The results are shown in Table 1 as Example 1. The bubble disappearance time was the average of the results of three samples.

(Bubble extinction test 2)
A simulated display device was produced in the same manner as in the foam extinction test 1 except that the transparent face material with an adhesive layer (2) was used instead of the transparent face material with an adhesive layer (1), and the foam disappearance time was measured. The results are shown in Table 1 as Example 2.

(Bubble extinction test 3)
A simulated display device was produced in the same manner as in the foam extinction test 1 except that the transparent face material with an adhesive layer (3) was used instead of the transparent face material with an adhesive layer (1), and the bubble disappearance time was measured. The results are shown in Table 1 as Example 3.

(90 degree peel test)
The transparent film with adhesive layer protected by the protective film (1) to (3) was cut into a protective film and an adhesive layer having a width of 25 mm and a length of about 90 mm. One end of the long side was peeled off by about 30 mm and set on an adhesive force measuring device (manufactured by Shimadzu Corporation, Autograph), and a 90-degree peel test was performed. The respective results are shown in Table 1 as Examples 1 to 3. The peeling speed was 60 mm / min. The judgment criteria are as follows: ○: Interfacial peeling (no adhesive layer left on the glass side).
X: Cohesive failure (adhesive layer is cut during peeling, and adhesive layer remains on both glass and protective film).

A graph of the concentration of the hydroxyl group in the adhesive layer and the bubble disappearance time in Examples 1 to 3 is shown in FIG. FIG. 14 shows a graph of the total concentration of the hydroxyl groups and the urethane bonds in the adhesive layers in Examples 1 to 3 and the bubble disappearance time. It can be seen that there is a correlation between the concentration of hydroxyl groups and the concentration of urethane bonds in the adhesive layer and the bubble disappearance time.
The unit of hydroxyl group concentration on the horizontal axis in FIG. 13 and the total unit of hydroxyl group concentration and urethane bond concentration on the horizontal axis in FIG. 14 are mol / (g × 10 ⁶ ).

(Example 4)
Production of transparent face material with adhesive layer (4):
The second composition (1) is applied with a dispenser over the entire circumference at a position of about 25 mm from the outer peripheral edge of the transparent face material (2) so that the width is about 1 mm and the application thickness is about 0.6 mm. A semi-cured weir was formed by irradiating ultraviolet rays from the LED light source attached thereto.
In the region inside the weir, the first composition (1) was supplied to a plurality of locations using a dispenser so that the total mass was 2.5 g. While supplying the first composition (1), there was no breakage such as breakage, and the shape of the semi-cured weir was maintained.

  The transparent surface material (2) is placed flat on the lower surface plate in the decompression device in which a pair of surface plate lifting devices are installed so that the surface coated with the first composition (1) is on the upper surface. did. The support surface material with the protective film was held on the upper surface plate in the decompression apparatus with the surface on which the protective film 16 was bonded down. It exhausted until the pressure in a decompression device became about 10,000 Pa, and was hold | maintained in that state for 1 minute. Thereafter, the upper and lower surface plates are brought close to each other by a lifting device in the decompression device, and the transparent surface material (2) and the support surface material with the protective film are pressure-bonded through the first composition (1) at a pressure of 2 kPa. And held for 10 seconds for bonding. After pasting, the inside of the decompression device was returned to the atmospheric pressure atmosphere to obtain a laminate in which the uncured adhesive layer made of the first composition (1) was sealed with the transparent surface material (2), the protective film and the weir.

The laminated body was irradiated with ultraviolet rays for 20 seconds from a high-pressure mercury light source (irradiation intensity: 100 mW / cm ² ) disposed on the support surface material side to cure the semi-cured weir and the uncured adhesive layer to form an adhesive layer. . The thickness of the adhesive layer after curing was approximately uniform at 0.4 mm.
Then, the transparent surface material (4) with the adhesion layer protected by the protective film was obtained by peeling a support surface material.
In Example 4, the storage shear modulus at 35 ° C. of the adhesive layer is 7000 Pa.

(Example 5)
Production of transparent face material with adhesive layer (5):
A transparent surface material (5) with an adhesive layer protected by a protective film was obtained in the same manner as in Example 4 except that the first composition (3) was used instead of the first composition (1).
In Example 5, the storage shear modulus at 35 ° C. of the adhesive layer is 10500 Pa.

(Example 6)
Production of transparent face material (6) with adhesive layer:
A laminate was obtained in the same manner as in Example 4 except that the first composition (4) was used instead of the first composition (1).
The laminated body is irradiated with ultraviolet rays for 10 minutes from a chemical lamp (NEC, FL15BL, irradiation intensity: ² mW / cm ² ) disposed on the support surface material side, and the semi-cured weir and the uncured adhesive layer are cured. An adhesive layer was formed. The thickness of the adhesive layer after curing was approximately uniform at 0.4 mm.
Then, the transparent surface material (6) with the adhesion layer protected by the protective film was obtained by peeling a support surface material.
In Example 6, the storage shear elastic modulus of the adhesive layer at 35 ° C. is 181000 Pa.

(Foam extinction test 4)
The protective film was peeled off from the transparent surface material (4) with an adhesive layer under normal pressure. The adhesive pad and electrostatic chuck are placed on the upper surface plate in the decompression device where the lifting device for the pair of surface plates is placed so that the surface of the adhesive layer faces downward. Used and held.
The polarizing plate bonded to the object to be bonded (2) on the lower surface plate of the lifting device in the decompression device with the object to be bonded (2) and the adhesive layer of the transparent surface material with an adhesive layer (4) Opposing, arrange | positioning so that the center location of a transparent surface material (4) with an adhesion layer and a polarizing plate may correspond, and it was made to hold | maintain so that the distance with a transparent surface material (4) with an adhesion layer might be set to 30 mm.
Exhaust until the pressure inside the decompression device becomes about 10,000 Pa with the decompression device sealed, and hold for 1 minute, then bring the upper and lower surface plates closer with the lifting device inside the decompression device, and the object to be bonded (2 ) And the pressure-sensitive adhesive layer-attached transparent surface material (4) were pressed with a pressure of 2 kPa through the adhesive layer and held for 10 seconds. The electrostatic chuck was neutralized and the object to be bonded (2) was separated from the upper surface plate, and the inside of the decompression device was returned to atmospheric pressure in about 20 seconds to obtain a simulated display device.
When the simulated display device was observed immediately after lamination with the transparent surface material with the adhesive layer (4), the polarizing plate bonded to the object to be bonded (2) and the adhesive layer of the transparent surface material with the adhesive layer (4) Many fine bubbles were seen at the interface. The simulated display device was allowed to stand, and the time until bubbles disappeared (bubble disappearance time) was measured. The results are shown in Table 2 as Example 4. The bubble disappearance time was the average of the results of three samples.

(Bubble extinction test 5)
A simulated display device was produced in the same manner as in the foam extinction test 4 except that the transparent face material with an adhesive layer (5) was used instead of the transparent face material with an adhesive layer (4), and the bubble disappearance time was measured. The results are shown in Table 2 as Example 5.

(Bubble extinction test 6)
A simulated display device was produced in the same manner as in the foam extinction test 4 except that the transparent face material with an adhesive layer (6) was used instead of the transparent face material with an adhesive layer (4), and the foam disappearance time was measured. The results are shown in Table 2 as Example 6.

(90 degree peel test)
A notch having a width of 25 mm and a length of about 90 mm was made in the protective film and the adhesive layer of the transparent surface material (4) to (6) with the adhesive layer protected by the protective film. One end of the long side was peeled off by about 30 mm and set on an adhesive force measuring device (manufactured by Shimadzu Corporation, Autograph), and a 90-degree peel test was performed. The respective results are shown in Table 2 as Examples 4 to 6. The peeling speed was 60 mm / min. Judgment criteria are as follows.
○: Interfacial peeling (no adhesive layer left on the glass side).
X: Cohesive failure (adhesive layer is cut during peeling, and adhesive layer remains on both glass and protective film).

  The graph of the density | concentration of the hydroxyl group in the adhesion layer in Examples 4-6 and bubble disappearance time is shown in FIG. The graph of the sum of the density | concentration of the hydroxyl group in the adhesion layer in Examples 4-6 and the density | concentration of a urethane bond, and bubble disappearance time is shown in FIG. It can be seen that there is a correlation between the concentration of hydroxyl groups and the concentration of urethane bonds in the adhesive layer and the bubble disappearance time.

(Example 7)
Production of pressure-sensitive adhesive sheet with protective film (1):
Using a die coater on the surface of a polyethylene terephthalate (PET) film (first substrate) (Purex (registered trademark) manufactured by Teijin Ltd.) whose mold has been released, the first composition (1 ) Was continuously applied at a thickness of 500 μm, and then sandwiched with a PET film (second substrate) (Teijin Purex (registered trademark)) having a surface release property higher than that of the first substrate. High pressure mercury light source (USHIO Electric Co., Ltd., UVC-05016S1TA01, irradiation intensity: 1500 mJ / cm ² ) is irradiated from the first base material side to completely cure the first composition (1), and an adhesive sheet with a protective film (1) was obtained. The storage shear modulus of the pressure-sensitive adhesive sheet at 35 ° C. is 5300 Pa.

(Bubble extinction test 7)
About the said adhesive sheet with a protective film, the 2nd base material of the adhesive sheet with a protective film (1) was peeled off under normal pressure, and it used for the foam extinction test. A simulated display device is prepared in the same manner as in the foam extinction test 1 except that the adhesive sheet (1) with a protective film is used instead of the transparent surface material (1) with an adhesive layer, and the foam disappearance time is measured. The bubble disappearance time is good.

According to the present invention, when the object to be bonded and the transparent surface material are bonded via the adhesive layer, the bubbles remaining at the interface between the object to be bonded and the adhesive layer quickly disappear, A transparent surface material with an adhesive layer in which no defects remain can be produced. This transparent surface material with an adhesive layer is useful as a protective plate for display panels, a protective plate for coordinate input devices, a substrate with transparent electrodes for coordinate input devices, and the like.
The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2014-085423 filed on April 17, 2014 are incorporated herein by reference. .

DESCRIPTION OF SYMBOLS 1 Transparent surface material with adhesion layer 2 Transparent surface material with adhesion layer 3 Display apparatus 10 Transparent surface material 12 Light-shielding printing part 14 Adhesion layer 15 Weir 16 Protective film 18 1st composition 20 Layer of partially cured material 22 Uncured weir 24 Area 26 First composition 28 Lower surface plate 30 Dispenser 32 Feed screw 34 Feed screw 36 Support surface material 38 Pressure reducing device 40 Suction pad 42 Upper surface plate 44 Lower surface plate 46 Air cylinder 48 Vacuum pump 50 Display panel 52 Transparent substrate 54 Transparent substrate 56 Liquid crystal layer 58 Polarizing plate 60 Flexible printed wiring board 62 Die coater 64 LED light source

Claims (18)

A transparent surface material, and an adhesive layer made of a cured product of the curable resin composition, formed on at least one surface of the transparent surface material,
The concentration of the hydroxyl group in the adhesive layer is 100 × 10 ⁻⁶ to 600 × 10 ⁻⁶ mol / g,
The transparent surface material with the adhesion layer whose density | concentration of the urethane bond in the said adhesion layer is 0-150 * 10 < ^-6 > mol / g. The sum of the concentration and the concentration of urethane linkages in the adhesive layer of the hydroxyl groups of the adhesive layer is a ^{100 × 10 -6 ~750 × 10 -6} mol / g, a transparent pressure-sensitive layer according to claim 1 Face material. The transparent surface material with the adhesion layer of Claim 1 or 2 whose solubility parameter of the said adhesion layer is 17.5-18.5 (J / cm < ³ >) < ^1/2 >. The curable resin composition comprises a curable oligomer (A) having an addition polymerizable unsaturated double bond, and a low molecular weight polymerizable compound (B) having an addition polymerizable unsaturated double bond,
Either one or both of the curable oligomer (A) and the low molecular weight polymerizable compound (B) have a hydroxyl group,
The pressure-sensitive adhesive layer according to any one of claims 1 to 3, wherein either one or both of the curable oligomer (A) and the low molecular weight polymerizable compound (B) may have a urethane bond. With transparent face material. The curable resin composition comprises a curable oligomer (A) having an addition polymerizable unsaturated double bond, a low molecular weight polymerizable compound (B) having an addition polymerizable unsaturated double bond, and an addition polymerizable non-polymerizable compound. A non-curable oligomer (C) having no saturated double bond,
At least one of the curable oligomer (A), the low molecular weight polymerizable compound (B) and the non-curable oligomer (C) has a hydroxyl group,
4. The system according to claim 1, wherein at least one of the curable oligomer (A), the low molecular weight polymerizable compound (B), and the non-curable oligomer (C) may have a urethane bond. The transparent surface material with the adhesion layer of one term | claim.   The transparent surface material with the adhesion layer as described in any one of Claims 1-5 which further has a peelable protective film which covers the surface of the said adhesion layer. It is a method of manufacturing the transparent surface material with the adhesion layer as described in any one of Claims 1-6, Comprising: The manufacturing method of the transparent surface material with an adhesion layer which has the following process ((alpha)) and the following process ((gamma)). .
(Α) A step of supplying the liquid curable resin composition to the surface of the transparent surface material and partially curing the curable resin composition as necessary to obtain a partially cured product.
(Γ) A step of curing the curable resin composition or the partially cured product to form the adhesive layer. The manufacturing method of the transparent surface material with the adhesion layer of Claim 7 which further has the following process ((beta)).
(Β) A step of covering the surface of the curable resin composition or the partially cured product with a protective film. The step (α) is the following step (α1), the step (β) is the following step (β1), and the step (γ) is the following step (γ1). Manufacturing method of transparent face material with adhesive layer.
(Α1) The liquid curable resin composition is supplied in a layer form on the surface of the transparent face material, and the curable resin composition supplied on the surface of the transparent face material is partially cured to be partially cured. Forming a layer.
(Β1) A step of covering the surface of the partially cured product layer with a protective film.
(Γ1) A step of further curing the partially cured product layer to form the adhesive layer. The step (α) is the following step (α21) and the following step (α22), the step (β) is the following step (β2), and the step (γ) is the following step (γ21) and the following step (γ21). The manufacturing method of the transparent surface material with the adhesion layer of Claim 8 which is a process ((gamma) 22).
(Α21) A step of forming a frame-like weir at the peripheral edge of the surface of the transparent face material.
(Α22) A step of supplying the curable resin composition to a region surrounded by the weir.
(Β2) Under a reduced-pressure atmosphere, the support surface material with a protective film is stacked on the curable resin composition layer so that the protective film is in contact with the surface of the curable resin composition layer, The process of obtaining the laminated body by which the layer of the said curable resin composition was sealed with the said transparent surface material, the said protective film, and the said dam.
(Γ21) A step of forming the adhesive layer by curing the layer of the curable resin composition in a state where the laminate is placed under a higher pressure atmosphere than in the step (β2).
(Γ22) A step of peeling the support surface material from the protective film after the step (γ21). A display panel;
The transparent surface material with an adhesive layer according to any one of claims 1 to 5, which is bonded to the display panel so that the adhesive layer is in contact with the display panel.
A display device. A method for manufacturing the display device according to claim 11, comprising:
The manufacturing method of the display apparatus which piles up and bonds the said display panel and the said transparent surface material with an adhesion layer so that the said adhesion layer may contact the said display panel in a pressure-reduced atmosphere. It is an adhesive sheet made of a cured product of a curable resin composition,
The concentration of the hydroxyl group in the pressure-sensitive adhesive sheet is 100 × 10 ⁻⁶ to 600 × 10 ⁻⁶ mol / g,
The adhesive sheet whose urethane bond density | concentration in the said adhesive sheet is 0-150x10 < ^-6 > mol / g. The pressure-sensitive adhesive sheet according to claim 13, wherein the total of the concentration of hydroxyl groups in the pressure-sensitive adhesive sheet and the concentration of urethane bonds in the pressure-sensitive adhesive sheet is 100 × 10 ^{−6 to} 750 × 10 ⁻⁶ mol / g. Solubility parameter of the cured product of the curable resin composition is ^{17.5~18.5 (J / cm 3) 1/2} , pressure-sensitive adhesive sheet according to claim 13 or 14. The curable resin composition comprises a curable oligomer (A) having an addition polymerizable unsaturated double bond, and a low molecular weight polymerizable compound (B) having an addition polymerizable unsaturated double bond,
Either one or both of the curable oligomer (A) and the low molecular weight polymerizable compound (B) have a hydroxyl group,
The pressure-sensitive adhesive sheet according to any one of claims 13 to 15, wherein either one or both of the curable oligomer (A) and the low molecular weight polymerizable compound (B) may have a urethane bond. . The curable resin composition comprises a curable oligomer (A) having an addition polymerizable unsaturated double bond, a low molecular weight polymerizable compound (B) having an addition polymerizable unsaturated double bond, and an addition polymerizable non-polymerizable compound. A non-curable oligomer (C) having no saturated double bond,
At least one of the curable oligomer (A), the low molecular weight polymerizable compound (B) and the non-curable oligomer (C) has a hydroxyl group,
Any one of the said curable oligomer (A), the said low molecular weight polymeric compound (B), and the said non-curable oligomer (C) may have a urethane bond, The any one of Claims 13-15 The pressure-sensitive adhesive sheet according to one item. The pressure-sensitive adhesive sheet according to any one of claims 13 to 17,
A peelable protective film covering at least one surface of the pressure-sensitive adhesive sheet;
A pressure-sensitive adhesive sheet with a protective film.

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