JP2019099616A - Optical transparent adhesive sheet, laminate, manufacturing method of optical transparent adhesive sheet, and laminate sheet - Google Patents

Abstract

To provide an optical transparent adhesive sheet in which generation of delayed foam generated by storage in a high temperature environment is suppressed by using a thermosetting polyurethane excellent in flexibility and capable of providing a thick film.SOLUTION: There is provided an optical transparent adhesive sheet constituted by thermosetting polyurethane, which is a cured article of the thermosetting polyurethane composition containing a polyol component, a polyisocyanate component and a silane coupling monomer, the silane coupling monomer contains an ethoxy group and an epoxy group.SELECTED DRAWING: Figure 3

Description

The present invention relates to an optically transparent pressure-sensitive adhesive sheet, a laminate, a method for producing an optically transparent pressure-sensitive adhesive sheet, and a laminated sheet.

An optically clear adhesive (OCA) sheet is a transparent adhesive sheet used for laminating optical members. In recent years, the demand for touch panels has been rapidly growing in the fields of smartphones, tablet PCs, portable game machines, car navigation devices, etc. With this, the demand for OCA sheets used to bond touch panels to other optical members Is also increasing. A display device provided with a touch panel generally includes a display panel such as a liquid crystal panel, a transparent member (touch panel main body) having a transparent conductive film made of ITO (indium tin oxide) or the like on the surface, and a cover for protecting the transparent conductive film. It has a structure where optical members, such as a panel, were laminated, and an OCA sheet is used for pasting between optical members. However, between the display panel and the touch panel main body, the end of the bezel, which is the housing of the display panel, is wider than the distance between the other optical members, and bonding with the OCA sheet is not performed. It was common to provide an air layer called.

However, if there is an air gap that is an air layer between the optical members, interface reflection occurs due to the difference in refractive index between the air layer and the optical members, and the visibility of the display panel is reduced. Therefore, a thick film OCA sheet suitable for bonding the display panel and the touch panel main body has been required. Moreover, covering the level difference formed by the thickness of a bezel is also calculated | required by the OCA sheet used for bonding of a display panel and a touch-panel main body. Therefore, an OCA sheet excellent in flexibility (step followability) and capable of being thickened is required.

Examples of documents disclosing prior art in the OCA sheet-related field include Patent Documents 1 and 2. The adhesive type optical film in which an adhesive layer is provided on an optical film is disclosed in Patent Document 1, wherein the adhesive layer comprises a polyol compound (a-1) having a weight average molecular weight of 500 to 4000, and an isocyanate compound (a-). 2), and a polyol compound (a-4) having two or more C = C bonds having radical polymerization property in one molecule, which are obtained by reaction, and the polyol (a-1) and the polyol compound (a-4) A polyurethane polymer (A) in which the compounding amount of the polyol compound (a-4) is 0.1 to 10% by weight with respect to the total amount of (A) as a base polymer, and the urethane polymer (A) 100 The adhesive type optical film characterized by containing 0.01-0.5 weight part of silane coupling agents (B) with respect to a weight part is disclosed. In all the examples of Patent Document 1, a silane coupling agent (KBM 403, manufactured by Shin-Etsu Silicone Co., Ltd.) is used as the silane coupling agent (B).

Patent Document 2 describes 100 parts by weight of a pressure-sensitive adhesive resin (A) and silicone alkoxy oligomers (B) 0.1 to 20 having an epoxy equivalent of 100 to 2000 g / mol and an alkoxyl group content of 5 to 60% by weight. Acrylic pressure-sensitive adhesive resin (A1), urethane-based pressure-sensitive adhesive resin (A2), and polyester-based pressure-sensitive adhesive, which are obtained by polymerizing a monomer containing no carboxyl group, wherein the pressure-sensitive adhesive resin (A) contains parts by weight A pressure-sensitive adhesive composition is disclosed, which is one or more selected from the group consisting of an agent resin (A3). In addition, it is described that the pressure-sensitive adhesive composition may further contain 0.001 to 5 parts by weight of a silane coupling agent (D) with respect to 100 parts by weight of the pressure-sensitive adhesive resin (A). (See claim 7). In Example 8 of Patent Document 2, KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd. is used as the silane coupling agent (D).

Patent No. 5016994 Specification JP, 2016-44291, A

As the OCA sheet, one formed of an ultraviolet curing adhesive is known. However, since an ultraviolet curing adhesive can not be irradiated with ultraviolet light at a portion to be a shadow of decorative printing or a portion to be a shadow of a material that absorbs ultraviolet light, it can not be cured sufficiently.

Therefore, the present inventors pay attention to using a thermosetting polyurethane composition which is film-formed without using a solvent and is cured by heating as a material of the OCA sheet which is excellent in flexibility and can be thickened. did. However, when various examinations were made on the OCA sheet obtained using the thermosetting polyurethane composition, when the OCA sheet is attached to the adherend and then stored in a high temperature environment, the interface between the adherend and the OCA sheet is It has been found that immediately after bonding, bubbles that do not exist and that are generated subsequently, that is, delayed bubbles (delay bubbles) are easily generated. In recent years, resin substrates composed of not only glass substrates but also acrylic resins, polycarbonate resins and the like have come to be used as adherends, but in the case of bonding to resin substrates , Delayed bubbles were easy to occur.

As a result of studies by the present inventors, it was found that the main cause of delayed bubbles is gas generated from the inside of the optical transparent pressure-sensitive adhesive sheet or the resin substrate, and the component of the gas is water in many cases. The generation of such delayed bubbles was a phenomenon unique to thermosetting polyurethanes. For example, an OCA sheet using an acrylic resin composition is likely to absorb moisture in a high temperature and high humidity environment, but has high adhesive strength and high gas permeability, so delayed bubbles are not a problem in particular. . Although the OCA sheet using silicone resin has low adhesion, it is very difficult to absorb moisture in a high temperature and high humidity environment, so delayed foam was not a problem in particular.

The present invention has been made in view of the above-mentioned present situation, and an optical fiber in which the generation of delayed bubbles caused by storage in a high temperature environment is suppressed by using a thermosetting polyurethane excellent in flexibility and capable of forming a thick film. It aims at providing a transparent adhesive sheet.

The present inventors examined the improvement of the environmental resistance of an optical transparent adhesive sheet using a thermosetting polyurethane, and using a thermosetting polyurethane composition containing a silane coupling monomer containing an ethoxy group and an epoxy group. Have found that they are effective in suppressing delayed bubbles and completed the present invention.

The optical transparent adhesive sheet of the present invention is an optical transparent adhesive sheet composed of a thermosetting polyurethane, and the thermosetting polyurethane contains a polyol component, a polyisocyanate component and a silane coupling monomer. The silane coupling monomer is characterized in that it contains an ethoxy group and an epoxy group.

The polyol component preferably contains an olefin-based polyol.

The laminate of the present invention comprises the first adherend, the second adherend, and the optically transparent pressure-sensitive adhesive sheet of the present invention for bonding the first adherend and the second adherend. It is characterized by having.

The first adherend may be a glass substrate. The second adherend may be a resin base material. The resin substrate may contain a polycarbonate.

The method for producing an optical transparent pressure-sensitive adhesive sheet of the present invention is a method for producing the optical transparent pressure-sensitive adhesive sheet according to the present invention, wherein the above-mentioned polyol component, the above-mentioned polyisocyanate component and the above-mentioned silane coupling monomer are stirred and mixed The method comprises the steps of preparing a polyurethane composition and curing the thermosetting polyurethane composition.

The laminated sheet of the present invention comprises the optical transparent adhesive sheet of the present invention, a first release film covering one surface of the optical transparent adhesive sheet, and a second release film covering the other surface of the optical transparent adhesive sheet. It is characterized in that a mold film is laminated.

According to the optically transparent pressure-sensitive adhesive sheet of the present invention, it is possible to suppress the generation of delayed bubbles caused by storage in a high temperature environment while obtaining the superiority of a thermosetting polyurethane which is excellent in flexibility and can be thickened. . Moreover, according to the laminate of the present invention, it is possible to maintain a transparent, bubble-free bonding interface. According to the method for producing an optical transparent pressure-sensitive adhesive sheet of the present invention, the optical transparent pressure-sensitive adhesive sheet of the present invention can be suitably produced. According to the laminated sheet of the present invention, the handleability of the optical transparent pressure-sensitive adhesive sheet of the present invention can be improved.

It is a figure explaining the effect | action mechanism of a silane coupling monomer. It is a schematic diagram for demonstrating the reason which a delayed bubble generate | occur | produces in the conventional laminated body. It is sectional drawing which showed typically an example of the display apparatus with a touch panel using the optical transparent adhesive sheet of this invention. It is a schematic diagram for demonstrating an example of the shaping | molding apparatus used for preparation of the optical transparent adhesive sheet of this invention. It is a schematic diagram for demonstrating the evaluation method of the adhesive force of an optical transparent adhesive sheet.

The optical transparent adhesive sheet of the present invention is an optical transparent adhesive sheet composed of a thermosetting polyurethane, and the thermosetting polyurethane contains a polyol component, a polyisocyanate component and a silane coupling monomer. The silane coupling monomer is characterized in that it contains an ethoxy group and an epoxy group. In addition, in this specification, an "optical transparent adhesive sheet" is synonymous with an "optical transparent adhesive film."

The optically transparent pressure-sensitive adhesive sheet of the present invention is composed of a thermosetting polyurethane. The optical transparent adhesive sheet made of polyurethane is flexible, stretches well and is very hard to break when a tensile stress is applied. For this reason, it is possible to peel off without adhesive residue. Moreover, since the optical transparent adhesive sheet of the present invention is flexible and can be thickened, it can be made excellent in impact resistance. Furthermore, since an optical transparent adhesive sheet made of polyurethane has a high dielectric constant and higher electrostatic capacitance than an optical transparent adhesive sheet made of a conventional acrylic resin composition, it is possible to use an electrostatic capacitive touch panel. It is suitably used for bonding.

The thermosetting polyurethane is preferably not acrylic-modified, and it is preferable that the main chain does not contain a site derived from an acrylic ester, a methacrylic ester or the like. When the thermosetting polyurethane is acrylic-modified, it becomes hydrophobic, and therefore, aggregation of water tends to occur under high temperature and high humidity. The aggregation of the water may cause whitening, foaming and the like, which may impair the optical properties. Therefore, by setting the thermosetting polyurethane not to be acrylic-modified, it is possible to prevent the deterioration of the optical characteristics due to whitening, foaming and the like under high temperature and high humidity. In the thermosetting polyurethane, the total amount of the monomer units derived from the polyol component and the monomer units derived from the polyisocyanate component is 80 mol% or more of the monomer units constituting the entire polyurethane. The monomer unit is preferably composed of only a monomer unit derived from a polyol component and a monomer unit derived from a polyisocyanate component.

[Polyol component]
The polyol component is not particularly limited, and examples thereof include polyether polyol, polycaprolactone polyol, polycarbonate polyol, polyester polyol and the like. These may be used alone or in combination of two or more.

Examples of the polyether polyols include polyethylene glycol, polypropylene glycol, polypropylene triol, polypropylene tetraol, polytetramethylene glycol, polytetramethylene triol, polyalkylene glycols such as copolymers thereof, and side chains introduced into these. And derivatives having a branched structure introduced, modified products, and mixtures of these.

Examples of the polycaprolactone polyol include polycaproate glycol, polycaprolactone triol, polycaprolactone tetraol, derivatives into which side chains are introduced or branched structures introduced into them, modified products, and mixtures of these, etc. It can be mentioned.

As said polycarbonate polyol, the reaction material of dialkyl carbonate and diol is mentioned, for example.

Examples of the dialkyl carbonate include dialkyl carbonates such as dimethyl carbonate and diethyl carbonate; diaryl carbonates such as diphenyl carbonate; and alkylene carbonates such as ethylene carbonate. These may be used alone or in combination of two or more.

Examples of the diol include 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 2-methyl-1, 8-octanediol, 1,9-nonanediol, 1,10-dodecanediol, 2-ethyl-1,6-hexanediol, 3-methyl-1,5-pentanediol, 2,4-dimethyl-1,5 -Pentanediol, neopentyl glycol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2,2'-bis (4-hydroxycyclohexyl) -propane and the like. These may be used alone or in combination of two or more. As the diol, an alicyclic or alicyclic diol having 4 to 9 carbon atoms is preferable, and, for example, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl 1,5-pentanediol, 2,4-dimethyl-1,5-pentanediol, 1,4-cyclohexanedimethanol, 1,7-heptanediol, 1,8-octanediol, 2-methyl-1,1,5-heptanediol It is preferable to use 8-octanediol and 1,9-nonanediol singly or in combination of two or more. As the diol, a copolycarbonate diol consisting of 1,6-hexanediol and 3-methyl-1,5-pentanediol, and a copolycarbonate diol consisting of 1,6-hexanediol and 1,5-pentanediol are also available. preferable.

In addition, as the polycarbonate polyol, for example, polycarbonate glycol, polycarbonate triol, polycarbonate tetraol, derivatives in which a side chain is introduced or a branched structure is introduced thereto, modified products, and a mixture thereof can also be used. it can.

As said polyester polyol, what carried out dehydration condensation of the dicarboxylic acid and the glycol component is mentioned, for example.

Examples of dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid and 2,6-naphthalenedicarboxylic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid and the like. Be

As the glycol component, for example, ethylene glycol, 1,4-butanediol, diethylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,5-pentanediol, 1,9-nonanediol, triethylene Aliphatic glycols such as glycols; alicyclic glycols such as 1,4-cyclohexanedimethanol; aromatic diols such as p-xylene diol; polyoxyalkylene glycols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol Be

The polyester polyol is a polyester having a linear molecular structure when formed by the dicarboxylic acid and glycol components exemplified above, but having a branched molecular structure using a trivalent or higher ester forming component. It may be. The dicarboxylic acid and the glycol component may be reacted at 150 to 300 ° C. at a molar ratio of 1.1 to 1.3.

The number average molecular weight of the polyol component is preferably 300 or more and 5,000 or less. When the number average molecular weight of the polyol component is less than 300, the reaction between the polyol component and the polyisocyanate component is too fast, which makes it difficult to form the thermosetting polyurethane into a uniform sheet, or the flexibility of the thermosetting polyurethane becomes It may become brittle due to a decrease in the sex. When the number average molecular weight of the polyol component exceeds 5000, the viscosity of the polyol component becomes too high, which makes it difficult to form the thermosetting polyurethane into a uniform sheet, or the thermosetting polyurethane crystallizes and becomes cloudy. And other problems may occur. The number average molecular weight of the polyol component is more preferably 500 or more and 2000 or less.

The polyol component is preferably one having an olefin skeleton, that is, one whose main chain is constituted by a polyolefin or a derivative thereof. Examples of the polyol component having an olefin skeleton include polybutadiene-based polyols such as 1,2-polybutadiene polyol, 1,4-polybutadiene polyol, 1,2-polychloroprene polyol and 1,4-polychloroprene polyol, and polyisoprene Polyols and those having their double bonds saturated with hydrogen or halogen etc. may be mentioned. Further, the polyol component may be a polyol obtained by copolymerizing an olefin compound such as styrene, ethylene, vinyl acetate or acrylic ester with a polybutadiene type polyol or the like or a hydrogenated product thereof. The polyol component may have a linear structure or may have a branched structure. Only one type of polyol component having an olefin skeleton may be used, or two or more types may be used. The polyol component used for the polyurethane preferably contains 80 mol% or more of a polyol component having an olefin skeleton, and more preferably consists only of the polyol component having an olefin skeleton.

Among the known polyol components having an olefin skeleton, for example, a polyolefin polyol (“EPOL (registered trademark)”) obtained by hydrogenating hydroxyl-terminated polyisoprene manufactured by Idemitsu Kosan Co., Ltd., number average molecular weight: 2500), both-end hydroxyl group hydrogenated polybutadiene (“GI-1000”, number average molecular weight: 1500) manufactured by Nippon Soda Co., Ltd., polyhydroxy polyolefin oligomer (“Polytail (registered trademark)”) manufactured by Mitsubishi Chemical Corporation, etc. may be mentioned. .

[Polyisocyanate component]
The polyisocyanate component is not particularly limited, and conventionally known polyisocyanates can be used, and hydrophilic polyisocyanate having a hydrophilic unit (hydrophilic group) and hydrophobic polyisocyanate having no hydrophilic unit Either one or both may be used.

An ethylene oxide unit is suitable as the hydrophilic unit. The action of suppressing whitening due to moisture absorption can be obtained by including the hydrophilic unit. It is preferable that content of the said ethylene oxide unit is 0.1 weight% or more and 20 weight% or less with respect to the whole thermosetting polyurethane composition. If the content is less than 0.1% by weight, whitening may not be sufficiently suppressed. When the content is more than 20% by weight, the compatibility with the low polar olefin-based polyol component, tackifier, plasticizer and the like is reduced, whereby the optical properties such as haze may be reduced. The content of the ethylene oxide unit is more preferably 0.1 to 5% by weight. When the content exceeds 5% by weight, the amount of moisture absorption in the high temperature and high humidity environment may be too large.

Examples of hydrophilic units other than ethylene oxide units include units containing a carboxylic acid group, an alkali metal base of carboxylic acid, a sulfonic acid group, an alkali metal base of sulfonic acid, a hydroxyl group, an amide group, an amino group and the like. More specifically, polyacrylic acid, alkali metal salt of polyacrylic acid, sulfonic acid group-containing copolymer, alkali metal salt of sulfonic acid group-containing copolymer, polyvinyl alcohol, polyacrylamide, carboxymethylcellulose, alkali metal of carboxymethylcellulose Salt, polyvinyl pyrrolidone and the like can be mentioned.

As a hydrophilic polyisocyanate which has the said hydrophilic unit, the modified polyisocyanate obtained by making aliphatic polyisocyanate and the ether compound which has an ethylene oxide unit react is used suitably, for example. By using the aliphatic polyisocyanate, it is possible to prevent the occurrence of coloration or discoloration of the optically transparent pressure-sensitive adhesive sheet, and to ensure the transparency of the optically transparent pressure-sensitive adhesive sheet for a long time more reliably. In addition, the polyisocyanate component can suppress whitening by the action of the hydrophilic portion (ethylene oxide unit) by forming a modified product in which an ether compound having an ethylene oxide unit is reacted, and the hydrophobic portion (other unit) The compatibility with low polarity tackifiers, plasticizers, etc. can be exhibited by the action of

Examples of the aliphatic polyisocyanate include hexamethylene diisocyanate, tetramethylene diisocyanate, 2-methyl-pentane-1,5-diisocyanate, 3-methyl-pentane-1,5-diisocyanate, lysine diisocyanate, trioxyethylene diisocyanate And isophorone diisocyanate, cyclohexyl diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, norbornane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated tetramethyl xylene diisocyanate, and modified products thereof. These may be used alone or in combination of two or more. In addition, as a modified body of hexamethylene diisocyanate, what carried out isocyanurate modification, allophanate modification, and / or urethane modification etc. of hexamethylene diisocyanate, etc. are mentioned, for example.

Examples of the ether compounds having ethylene oxide units include ethylene oxide adducts of alcohols, phenols and / or amines, and from the viewpoint of enhancing hydrophilicity, those having three or more ethylene oxide units per molecule It is preferably used.

Examples of the alcohol include monohydric alcohols, dihydric alcohols (ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,3-butylenediol And peopentyl glycol etc., trihydric alcohols (glycerin, trimethylolpropane etc.). These may be used alone or in combination of two or more.

Examples of the above-mentioned phenols include hydroquinone, bisphenols (bisphenol A, bisphenol F, etc.), and formalin low condensates of phenol compounds (novolak resin, intermediate of resole). These may be used alone or in combination of two or more.

The number of isocyanate groups per molecule of the modified polyisocyanate is preferably 2.0 or more on average. If the number of isocyanate groups is less than 2.0 on average, the decrease in the crosslink density may result in the thermosetting polyurethane composition not sufficiently curing.

The above-mentioned hydrophobic polyisocyanate is not particularly limited, but aliphatic isocyanates are suitably used. For example, hexamethylene diisocyanate (HDI), tetramethylene diisocyanate, 2-methyl-pentane-1,5-diisocyanate, 3-methyl -Pentane-1,5-diisocyanate, lysine diisocyanate, trioxyethylene diisocyanate, isophorone diisocyanate (IPDI), cyclohexyl diisocyanate, 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), norbornane diisocyanate (NBDI), hydrogenated tolylene And isocyanates, hydrogenated xylene diisocyanate, hydrogenated tetramethyl xylene diisocyanate, and modified products thereof. These may be used alone or in combination of two or more.

The compounding ratio of the hydrophilic polyisocyanate having the hydrophilic unit and the hydrophobic polyisocyanate not having the hydrophilic unit is preferably 9: 1 to 1: 1, from the viewpoint of achieving both the prevention of whitening and the reduction of the moisture absorption rate. 9, and more preferably 7: 3 to 3: 7.

The thermosetting polyurethane composition preferably has an α ratio of 1 or more (mole number of OH group derived from polyol component / mole number of NCO group derived from polyisocyanate component). When the α ratio is less than 1, the amount of the polyisocyanate component is excessive with respect to the amount of the polyol component, so the thermosetting polyurethane becomes hard, and the flexibility required for the optical transparent adhesive sheet is It becomes difficult to secure. If the flexibility of the optical transparent pressure-sensitive adhesive sheet is low, in particular, when bonding an optical member such as a touch panel, it is not possible to cover the unevenness and the level difference present on the bonding surface. Moreover, there is a possibility that the adhesive force required for the optical transparent adhesive sheet can not be secured. The α ratio more preferably satisfies 1.3 <α <2.0. When the α ratio is 2.0 or more, the thermosetting polyurethane composition may not be cured sufficiently.

[Silane coupling monomer]
The silane coupling monomer is a silane compound containing an ethoxy group (-OC 2 _{H 5)} and an epoxy group. The number of ethoxy groups and the number of epoxy groups contained in the molecule are not particularly limited, but silane compounds having two or three ethoxy groups and one epoxy group are preferably used. Examples of silane coupling monomers containing an ethoxy group and an epoxy group include 3-glycidoxypropylmethyldiethoxysilane and 3-glycidoxypropyltriethoxysilane. If a silane coupling monomer containing an epoxy group is used, reaction inhibition between the polyol component and the polyisocyanate component does not occur, and a thermosetting polyurethane having stable characteristics can be obtained. Moreover, the thermosetting polyurethane obtained using the silane coupling monomer containing an epoxy group is not seen yellowing, and is excellent also in the adhesive force to a base material. Furthermore, according to the study of the present inventor, although the thermosetting polyurethane obtained using the silane coupling monomer containing an epoxy group is likely to generate delayed bubbles, the alkoxy contained in the silane coupling monomer By selecting the ethoxy group instead of the methoxy group as the group, the hydrolysis reaction can be delayed, and the outgas that causes foaming can be reduced, so that the generation of delayed foam can be prevented.

FIG. 1 is a view for explaining the action mechanism of the silane coupling monomer. As shown in FIG. 1, the silane coupling monomer is hydrolyzed by water to be silanol and then partially condensed to form an oligomer. Subsequently, the surface of the adherend 100 is adsorbed by an interaction such as hydrogen bonding. Thereafter, when a dehydration condensation reaction occurs due to heating or the like, it chemically strongly bonds to the surface of the adherend 100. As described above, the optical transparent pressure-sensitive adhesive sheet of the present invention does not exhibit high adhesive strength immediately after bonding, and by heating, the adhesive strength is significantly improved and can be firmly bonded to the adherend. Therefore, the optical transparent adhesive sheet of the present invention is excellent in reworkability.

It is preferable that content of the said silane coupling agent is 0.2 weight% or more and 3 weight% or less with respect to a thermosetting polyurethane composition. When content of a silane coupling agent is less than 0.2 weight%, the effect of the adhesive force improvement of the optical transparent adhesive sheet by addition of a silane coupling agent may not fully be acquired. When content of a silane coupling agent exceeds 3 weight%, there exists a possibility that the adhesive force of an optical transparent adhesive sheet may fall because a silane coupling agent segregates on the surface of an optical transparent adhesive sheet.

[Tackfire]
The thermosetting polyurethane composition may further contain a tackifier (tackifier). A tackifier is an additive that is added to improve adhesion, and is usually an amorphous oligomer with a molecular weight of several hundred to several thousand, and is a thermoplastic resin that is liquid or solid at normal temperature. When the thermosetting polyurethane composition contains a tackifier, the adhesion of the optically transparent pressure-sensitive adhesive sheet formed of the cured product of the thermosetting polyurethane composition can be improved.

The above-mentioned tackifier is not particularly limited, and examples thereof include petroleum resin-based tackifiers, hydrocarbon resin-based tackifiers, rosin-based tackifiers, terpene-based tackifiers and the like. Only one type of these may be contained, or two or more types may be contained.

As the above-mentioned tackifier, a petroleum resin-based tackifier is suitably used since it is excellent in compatibility with the polyol component having the above-mentioned olefin skeleton. Among the above-mentioned petroleum resin-based tackifiers, a hydrogenated petroleum resin obtained by hydrogenating a copolymer of dicyclopentadiene and an aromatic compound is preferably used. Dicyclopentadiene is obtained from the C5 fraction. As said aromatic compound, vinyl aromatic compounds, such as styrene, (alpha)-methylstyrene, vinyl toluene, are mentioned, for example. The ratio of dicyclopentadiene to the vinyl aromatic compound is not particularly limited, but on a weight basis, it is preferable that dicyclopentadiene: vinyl aromatic compound = 70: 30 to 20:80, 60:40 to 40:60. It is more preferable that The preferable softening point of the above-mentioned hydrogenated petroleum resin is 90 to 160 ° C., the preferable vinyl aromatic compound unit content is 35 mass% or less, the preferable bromine number is 0 to 30 g / 100 g, and the preferable number average molecular weight is 500 to 1100. As a well-known thing among the said hydrogenated petroleum resin, "Iimab P-100" by Idemitsu Kosan Co., Ltd. is mentioned, for example.

As said tackifier, since it is excellent in compatibility with the polyol component etc. which have the said olefin frame, a hydrocarbon resin type tackifier is used suitably. Among the above-mentioned hydrocarbon resin tackifiers, alicyclic saturated hydrocarbon resins are preferably used. Among the above-mentioned alicyclic saturated hydrocarbon resins, known ones include, for example, "Arcon P-100" manufactured by Arakawa Chemical Industries, Ltd.

It is preferable that content of the said tackifier is 1 weight% or more and 20 weight% or less with respect to a thermosetting polyurethane composition. When the content of the tackifier is less than 1% by weight, the adhesion of the optical transparent adhesive sheet may not be sufficiently improved, and in particular, the adhesion under high temperature and high humidity may be insufficient. . When the content of the tackifier exceeds 20% by weight, the reaction between the polyol component and the polyisocyanate component may be inhibited, and urethane crosslinking may not be sufficiently formed in the thermosetting polyurethane. As a result, the optical transparent pressure-sensitive adhesive sheet may be dissolved and the shape may change or the tackifier may be precipitated (bleed) under high temperature and high humidity. In addition, if the reaction time between the polyol component and the polyisocyanate component is increased to sufficiently form urethane crosslinking, the productivity is lowered.

[Plasticizer]
The thermosetting polyurethane composition may further contain a plasticizer. By the addition of the plasticizer, the hardness can be reduced, whereby the handling property and the level difference followability of the optical transparent pressure-sensitive adhesive sheet of the present invention can be improved.

The plasticizer is not particularly limited as long as it is a compound used to impart flexibility to a thermoplastic resin, but from the viewpoint of compatibility and weather resistance, it is preferable to include a carboxylic plasticizer. Examples of the carboxylic acid plasticizer include phthalic acid esters such as diundecyl phthalate, dioctyl phthalate, diisononyl phthalate, diisodecyl phthalate, and dibutyl phthalate (phthalic acid plasticizers), and 1,2-cyclohexanedicarboxylic acid. Acid diisononyl ester, adipic acid ester, trimellitic acid ester, maleic acid ester, benzoic acid ester, poly-α-olefin and the like can be mentioned. Only one type of these may be contained, or two or more types may be contained. Among the above-mentioned carboxylic acid plasticizers, for example, “DINCH” manufactured by BASF, “San-sizer DUP” manufactured by Shin Nippon Rika, “Durasyn (registered trademark) 148” manufactured by Iones Oligomers, etc. Can be mentioned.

[catalyst]
The thermosetting polyurethane composition may further contain a catalyst. The catalyst is not particularly limited as long as it is a catalyst used for the urethanation reaction, for example, organic tin compounds such as di-n-butyl tin dilaurate, dimethyl tin dilaurate, dibutyl tin oxide, octane tin, etc .; organic titanium compounds Organic zirconium compounds; carboxylic acid tin salts; carboxylic acid bismuth salts; amine-based catalysts such as triethylenediamine.

In the above-mentioned thermosetting polyurethane composition, various additives such as a coloring agent, a stabilizer, an antioxidant, a mildew, a flame retardant and the like are optionally added within the range not to impair the required characteristics of the optical transparent pressure sensitive adhesive sheet. It may be added.

It is preferable that the thickness of the optical transparent adhesive sheet of this invention is 50-3000 micrometers. In the case where the thickness is less than 50 μm, when one surface of the optically transparent pressure-sensitive adhesive sheet is attached to the surface of the optical member, the optically transparent pressure-sensitive adhesive sheet may cover asperities or steps existing on the surface of the optical member In some cases, the other surface of the optical transparent pressure-sensitive adhesive sheet can not be attached to the surface of another optical member with sufficient adhesion. Further, the thicker the optical transparent adhesive sheet, the larger the amount of moisture absorption, and therefore delayed bubbles due to moisture absorption tend to occur, but if the thickness is 3000 μm or less, delayed bubbles due to moisture absorption can be sufficiently suppressed. The preferable lower limit of the thickness of the optical transparent pressure-sensitive adhesive sheet is 100 μm, the more preferable lower limit is 250 μm, and the preferable upper limit is 2000 μm. Moreover, it is preferable that an optical transparent adhesive sheet has thickness 3 times or more with respect to the height of the unevenness | corrugation or level | step difference which exists in the sticking surface of a to-be-adhered body.

The optical transparent adhesive sheet of the present invention preferably has an adhesive strength at 23 ° C. of 10 N / 25 mm or less, and an adhesive strength of 15 N / 25 mm or more after holding at 80 ° C. for 2 hours. By incorporating a silane coupling monomer containing an ethoxy group and an epoxy group into the thermosetting polyurethane composition, the optically transparent pressure-sensitive adhesive sheet of the present invention does not exhibit high adhesion immediately after bonding, and heating is possible. By doing this, the adhesive strength can be greatly improved, and it can be firmly bonded to the adherend. If the adhesive strength at 23 ° C. is 10 N / 25 mm or less, when the optically transparent adhesive sheet is used for laminating optical members such as a touch panel, it can be peeled without adhesive residue, and therefore, the reworkability is excellent. Moreover, when the adhesive force of an optical transparent adhesive sheet becomes large too much, it may become difficult to pull out the bubble which entered between the optical transparent adhesive sheet and a to-be-adhered body at the time of bonding. If the adhesive strength after holding at 80 ° C. for 2 hours is less than 15 N / 25 mm, the generation of delayed bubbles may not be suppressed.

The said adhesive force points out the value measured by the 180 degree peeling test which makes a base material made of glass or a polycarbonate a to-be-adhered body. The 180 ° peel test can be conducted by the following method to measure the adhesion (N / 25 mm). FIG. 5: is a schematic diagram for demonstrating the evaluation method of the adhesive force of an optical transparent adhesive sheet. First, the optically transparent adhesive sheet is cut into a length of 75 mm × a width of 25 mm to obtain a test piece. Then, the optically transparent pressure-sensitive adhesive sheet 12 is attached to the substrate 31 having a length of 75 mm and a width of 25 mm, held at a pressure of 0.4 MPa for 30 minutes, and the optically transparent pressure-sensitive adhesive sheet 12 and the substrate 31 are bonded. Then, as shown to Fig.5 (a), the 125-micrometer-thick PET sheet 32 is affixed on the surface on the opposite side to the base material 31 of the optical transparent adhesive sheet 12. As shown in FIG. Next, as shown in FIG. 5 (b), the PET sheet 32 is pulled in the direction of 180 °, the optically transparent adhesive sheet 12 is peeled off at the interface with the substrate 31, and adhesion of the optically transparent adhesive sheet 12 to the substrate 31 Measure the force.

The optical transparent adhesive sheet of the present invention preferably has a haze of 0.5% or less and a total light transmittance of 90% or more in order to ensure the performance as an optical transparent adhesive sheet. . The haze and the total light transmittance can be measured, for example, using a turbidity meter “HazeMeter NDH 2000” manufactured by Nippon Denshoku Industries Co., Ltd. The haze is measured by the method according to JIS K 7136, and the total light transmittance is measured by the method according to JIS K 7361-1.

A release film may be attached to both sides of the optical transparent adhesive sheet of the present invention. The optical transparent adhesive sheet of the present invention, a first release film covering one side of the optical transparent adhesive sheet, and a second release film covering the other side of the optical transparent adhesive sheet are laminated The laminated sheet (hereinafter, also referred to as "the laminated sheet of the present invention") which is one of them is also an aspect of the present invention. By attaching the first and second release films, the surface of the optical transparent pressure-sensitive adhesive sheet of the present invention can be protected until just before being attached to the adherend. As a result, it is possible to prevent the decrease in adhesiveness and the adhesion of foreign matter. Moreover, since it can prevent sticking other than a to-be-adhered body, the handleability of the optical transparent adhesive sheet of this invention can be improved.

For example, a polyethylene terephthalate (PET) film can be used as the first and second release films. The material and thickness of the first release film and the second release film may be the same or different.

The bonding strength (peel strength) of the optical transparent adhesive sheet of the present invention to the first release film and the bonding strength of the optical transparent adhesive sheet of the present invention to the second release film may be different from each other preferable. The optical transparent adhesion which peeled and exposed only one of the first and second release films (the release film with the weaker bonding strength) from the laminated sheet of the present invention due to the difference in the bonding strength. The first surface of the sheet and the first adherend were laminated, and then the other of the first and second release films (the release film with higher adhesion strength) was peeled off and exposed It becomes easy to bond together the 2nd surface and the 2nd adherend of an optical transparent adhesive sheet. The surface of the first release film in contact with the optical transparent adhesive sheet of the present invention, and the surface of the second release film in contact with the optical transparent adhesive sheet of the present invention, or both An easy peeling process (mold releasing process) may be performed. As an easy peeling process, a silicon process is mentioned, for example.

The application of the optical transparent pressure-sensitive adhesive sheet of the present invention is not particularly limited, and a first adherend, a second adherend, and the first adherend and the second adherend are joined. A laminate comprising the optical transparent pressure-sensitive adhesive sheet of the present invention is also an aspect of the present invention. As a 1st and 2nd to-be-adhered body, a glass base material and a resin base material are used suitably, for example. The materials of the first and second adherends may be the same or different. For example, the first adherend is a glass substrate and the second adherend is It may be a resin base material.

In addition, when a glass base material and a resin base material are bonded together by the conventional optical transparent adhesive sheet, a delayed bubble may be mainly generated in the interface of a glass base material and an optical transparent adhesive sheet. FIG. 2 is a schematic view for explaining the reason why delayed bubbles occur in the conventional laminate. As shown in FIG. 2, the water 61 contained in the inside of the resin base material 52 is vaporized by heating and passes through the optical transparent adhesive sheet 12 to gather at the interface between the glass base 51 and the optical transparent adhesive sheet 12. It is presumed that bubbles (delayed bubbles) 60 are formed.

The said glass base material will not be specifically limited if the surface which contact | connects an optical transparent adhesive sheet was comprised with glass, For example, Display apparatuses, such as a display panel, a touch panel (glass substrate with an ITO transparent conductive film), a cover glass The various members made of glass which comprise these are mentioned. The type of display panel is not particularly limited, and examples thereof include a liquid crystal panel and an organic electroluminescence panel (organic EL panel). By bonding various members in the display using the optically transparent adhesive sheet, the air layer (air gap) in the display can be eliminated, and the visibility of the display screen can be improved. Moreover, if an optical transparent adhesive sheet is stuck on a glass base material, the effect which prevents scattering of glass will be acquired.

The said resin base material will not be specifically limited if the surface which contact | connects an optical transparent adhesive sheet was comprised by resin (plastic), For example, resin which comprises display apparatuses, such as a cover panel, a polarizing plate, retardation film Made of various materials. The resin substrate may include a portion made of a material other than resin, but from the viewpoint of obtaining the effect of the present invention to suppress the generation of delayed bubbles, the thickness of the portion made of resin is 1 mm It is preferable that it is more than. If the thickness of the portion made of resin is less than 1 mm, the amount of water contained in the inside of the resin base material is small, so there is a possibility that the need to suppress the generation of delayed bubbles is small.

It does not specifically limit as resin which comprises the said resin base material, For example, a polycarbonate, polymethyl methacrylate resin (PMMA), triacetyl cellulose (TAC) etc. are mentioned. Among them, polycarbonate is preferable from the viewpoint of obtaining the effect of the present invention for suppressing the generation of delayed bubbles. In the case where the resin substrate contains a polycarbonate, delayed bubbles are likely to be generated remarkably, and the generation of delayed bubbles can be effectively suppressed by the present invention. Moreover, when the resin base material is a polarizing plate, the surface which contact | connects an optical transparent adhesive sheet may be comprised with a triacetyl cellulose.

As a laminated body of this invention, the display apparatus with a touch panel provided with the optical transparent adhesive sheet of this invention, a display panel, and a touch panel is mentioned, for example. FIG. 3: is sectional drawing which showed typically an example of the display apparatus with a touch panel using the optical transparent adhesive sheet of this invention. In the display device 10 shown in FIG. 3, the display panel 11, the optically transparent adhesive sheet 12, the touch panel (glass substrate with ITO transparent conductive film) 13, the optically transparent adhesive sheet 12, and the transparent cover panel 14 are sequentially stacked. The three optical members of the display panel 11, the touch panel 13 and the transparent cover panel 14 are integrated by two optically transparent adhesive sheets 12 of the present invention. The type of the display panel 11 is not particularly limited, and, for example, a liquid crystal panel, an organic electroluminescence panel (organic EL panel), or the like can be used. As the touch panel 13, for example, a detection method such as a resistance film method or a capacitance method is used.

The display panel 11 is housed in a bezel (a housing of the display panel 11) 11A having an opening on the display surface side, and a step corresponding to the thickness of the bezel 11A is present at the outer edge of the opening of the bezel 11A. Do. The optically transparent adhesive sheet 12 is attached to cover the display surface side of the display panel 11 and the bezel 11A, and covers a step corresponding to the thickness of the bezel 11A. In order to cover the step formed by the thickness of the bezel 11A, the optical transparent adhesive sheet 12 is required to have flexibility to follow the step and a thickness greater than the thickness of the bezel 11A. Thus, it is preferable that the thickness of the optically transparent adhesive sheet 12 used for bonding with the display panel 11 accommodated in the bezel 11A is, for example, 700 μm or more. The optical transparent pressure-sensitive adhesive sheet of the present invention has sufficient optical properties and flexibility even if it has a thickness of 700 μm or more, and is preferably used for bonding with the display panel 11 housed in the bezel 11A. it can.

In such a display device, since the optical transparent adhesive sheet of the present invention is used, the adhesive power of the optical transparent adhesive sheet is unlikely to decrease even when used under various environments, and the optical member is used for a long period of time It can be stuck to each other. As a result, since a space | gap does not generate | occur | produce between each optical member and an optical transparent adhesive sheet, the fall of the visibility by the increase of interface reflection etc. can be prevented. The optical transparent adhesive sheet of the present invention can be used, for example, in an on-vehicle display device such as a display device incorporated in a car navigation device or a display device for a portable device such as a smartphone.

The process for producing the transparent optical pressure-sensitive adhesive sheet of the present invention is not particularly limited. For example, after preparing a thermosetting polyurethane composition, a method may be mentioned in which the composition is thermally cured by a conventionally known method. And a step of preparing a thermosetting polyurethane composition by stirring and mixing a polyol component, a polyisocyanate component and a silane coupling monomer, and curing the thermosetting polyurethane composition.

As the polyol component, the polyisocyanate component and the silane coupling monomer, those which are liquid at normal temperature (23 ° C.) can be used, and a thermosetting polyurethane can be obtained without using a solvent. Other components such as tackifiers can be added to either the polyol component and the polyisocyanate component, and are preferably added to the polyol component. Thus, when producing an optical transparent adhesive sheet using a thermosetting polyurethane composition, since removal of a solvent is unnecessary, a uniform sheet | seat can be thickly formed. For this reason, when using the optical transparent adhesive sheet of this invention for bonding of a display panel and the transparent member (touch panel) which has a transparent conductive film in surface layer, the level | step difference of a bezel can be covered.

As an example of the manufacturing method, first, a master batch is prepared by adding a predetermined amount of tackifier to the polyol component and dissolving it by heating and stirring. Subsequently, the obtained masterbatch, the polyol component, the polyisocyanate component, the silane coupling monomer, and other components such as the catalyst as required are mixed, and the mixture is stirred by a mixer or the like to form a liquid or gel. A thermosetting polyurethane composition is obtained. Thereafter, the thermosetting polyurethane composition is immediately charged into a molding apparatus, and the thermosetting polyurethane composition is moved while being moved between the first and second release films, thereby causing crosslinking and curing. The polyurethane composition is semi-cured to obtain a sheet integrated with the first and second release films. Thereafter, a cross-linking reaction is carried out in a furnace for a fixed time to obtain an optically transparent pressure-sensitive adhesive sheet comprising a cured product of a thermosetting polyurethane composition, and the laminate sheet of the present invention is completed.

FIG. 4: is a schematic diagram for demonstrating an example of the shaping | molding apparatus used for preparation of the optical transparent adhesive sheet of this invention. In the forming apparatus 20 shown in FIG. 4, first, a pair of release films in which the liquid or gel thermosetting polyurethane composition 23 before curing is continuously fed from a pair of forming rolls 22 arranged at a distance from each other. (PET film) 21 is poured into the gap. Then, while the thermosetting polyurethane composition 23 is held in the gap between the pair of release films 21, it is carried into the heating device 24 while advancing the curing reaction (crosslinking reaction). In the heating device 24, the thermosetting polyurethane composition 23 is thermally cured in a state of being held between a pair of release films (PET film) 21, and an optically transparent adhesive sheet comprising a cured product of the thermoplastic polyurethane composition The molding of 12 is completed.

As a process for producing the optically transparent adhesive sheet of the present invention, after preparing a thermosetting polyurethane composition before curing, a general-purpose film forming apparatus such as various coating apparatus, bar coat, doctor blade or the like and a film forming method are used. It may be. In addition, the optical transparent pressure-sensitive adhesive sheet of the present invention may be produced using a centrifugal molding method.

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

Example 1
100 parts by weight of a polyolefin polyol ("EPOL (registered trademark)" manufactured by Idemitsu Kosan Co., Ltd., number average molecular weight: 2500), 10 parts by weight of a modified polyisocyanate ("Coronato 4022" manufactured by Tosoh Corp.) having a hydrophilic unit, 1.5 parts by weight of 3-glycidoxypropylmethyldiethoxysilane ("KBE-402" manufactured by Shin-Etsu Chemical Co., Ltd.), hydrogenated petroleum resin-based tackifier ("Aimab P-100" manufactured by Idemitsu Kosan Co., Ltd.) 20 Parts by weight and 0.05 parts by weight of dimethyltin dilaurate ("Fomrez catalyst UL-28" manufactured by Momentive) are mixed by stirring using a reciprocating rotary agitator, and the α ratio is 1.85. A thermosetting polyurethane composition was prepared.

Thereafter, the obtained thermosetting polyurethane composition was injected into the molding apparatus 20 shown in FIG. Then, while conveying the thermosetting polyurethane composition in a state of being sandwiched by a pair of release films (PET film whose surface has been subjected to release treatment) 21, conditions of an oven temperature of 70 ° C. and an oven time of 10 minutes It was cross-linked and hardened. Then, the crosslinking reaction was performed for 12 hours by the heating device 24 adjusted to 70 ° C., and an optically transparent adhesive sheet 12 made of a cured product of the thermosetting polyurethane composition was produced. The thickness of the optical transparent adhesive sheet 12 was 150 μm.

Optically bonded to a transparent glass substrate (soda glass manufactured by Matsunami Glass Co., Ltd.) by vacuum bonding one surface of the optical transparent adhesive sheet from which the mold release film was peeled off at a pressure of 0.15 MPa and peeling the mold release film A 2 mm-thick resin substrate was vacuum bonded to the other surface of the transparent adhesive sheet at a pressure of 0.15 MPa, and a laminate was obtained by bonding a glass substrate and a resin substrate by an optically transparent adhesive sheet. . As a resin base material, hard coating is applied to both sides of "UW2-070" manufactured by Kuraray Co., Ltd., which is a resin board obtained by acrylic primer treatment of one side of a polycarbonate board ("MT2LX" manufactured by Kuraray Co., Ltd.) An optically clear pressure-sensitive adhesive sheet was attached to the side not subjected to the acrylic primer treatment using the one to which "PMR" was applied.

Finally, the resulting laminate was heated at 85 ° C. for 1 hour. Before heating, bonding of the glass substrate and the optical transparent adhesive sheet, and bonding of the resin substrate and the optical transparent adhesive sheet can be easily peeled off, and the optical transparent adhesive sheet may be used if necessary. It was possible to paste again. On the other hand, after heating, the optically transparent pressure-sensitive adhesive sheet was chemically bonded to the surfaces of the glass substrate and the resin substrate, and the glass substrate and the resin substrate were firmly adhered by the optically transparent pressure-sensitive adhesive sheet. In addition, although it heated in order to shorten the time which adhesion | attachment requires, sufficient adhesive strength is obtained only by leaving it to stand at normal temperature for about 1 day.

(Example 2 and Comparative Example 1)
As in Example 1 except that the type of silane coupling monomer was changed as shown in Table 1 below, an optical transparent adhesive sheet with a release film according to Example 2 and Comparative Example 1 was prepared. . And the laminated body which bonded the glass base material and the resin base material together using the optically transparent adhesive sheet which concerns on Example 2 and the comparative example 1 was obtained.

(Evaluation test)
In each of the laminates according to Examples 1 and 2 and Comparative Example 1, no bubbles having a visible size were generated when viewed from the transparent glass substrate side at the time of preparation. These laminates were stored at 85 ° C. and 85% RH for 144 hours, after which the laminates were visually observed from the transparent glass substrate side to confirm the occurrence of delayed bubbles. The test results are shown in Table 1 below.

In addition, silane coupling monomers A to C in Table 1 represent the following compounds or commercially available products.
A: 3-glycidoxypropylmethyldiethoxysilane ("KBE-402" manufactured by Shin-Etsu Chemical Co., Ltd.)
B: 3-glycidoxypropyl triethoxysilane ("KBE-403" manufactured by Shin-Etsu Chemical Co., Ltd.)
C: 3-glycidoxypropyl trimethoxysilane ("KBM-403" manufactured by Shin-Etsu Chemical Co., Ltd.)

As can be seen from Table 1, the optically transparent adhesive sheets of Examples 1 and 2 did not generate delayed bubbles. On the other hand, delayed bubbles occurred in the optical transparent adhesive sheet of Comparative Example 1.

DESCRIPTION OF SYMBOLS 10 display device 11 display panel 11A bezel 12 optical transparent adhesive sheet 13 touch panel 14 transparent cover panel 20 forming device 21 release film 22 forming roll 23 thermosetting polyurethane composition 24 heating device 31 base 32 PET sheet 51 glass base 52 Resin base material 60 air bubble (late bubble)
61 water 100 adherend

Claims (8)

It is an optical transparent adhesive sheet made of thermosetting polyurethane,
The thermosetting polyurethane is a cured product of a thermosetting polyurethane composition containing a polyol component, a polyisocyanate component and a silane coupling monomer,
The optically transparent pressure-sensitive adhesive sheet, wherein the silane coupling monomer comprises an ethoxy group and an epoxy group. The optical transparent adhesive sheet according to claim 1, wherein the polyol component comprises an olefin-based polyol. The optical transparent adhesive sheet according to claim 1 or 2, wherein a first adherend, a second adherend, and the first adherend and the second adherend are joined. A laminate characterized by The laminate according to claim 3, wherein the first adherend is a glass substrate. The laminate according to claim 3 or 4, wherein the second adherend is a resin base material. The said resin base material contains a polycarbonate, The laminated body of Claim 5 characterized by the above-mentioned. A method of producing the optical transparent pressure-sensitive adhesive sheet according to claim 1 or 2,
Preparing the thermosetting polyurethane composition by stirring and mixing the polyol component, the polyisocyanate component and the silane coupling monomer;
Curing the thermosetting polyurethane composition. The optical transparent adhesive sheet according to claim 1, a first release film covering one surface of the optical transparent adhesive sheet, and a second release film covering the other surface of the optical transparent adhesive sheet And a laminated sheet.

Images