JP6538332B2 - Optical double-sided adhesive sheet - Google Patents

Description

  The present invention relates to an optical double-sided pressure-sensitive adhesive sheet. More specifically, the present invention relates to an optical double-sided pressure-sensitive adhesive sheet used for an on-vehicle optical product.

  In recent years, display devices such as liquid crystal displays (LCDs) and input devices such as touch panels used in combination with such display devices have come to be widely used in various fields. In these display devices, input devices and the like, a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer is used for the purpose of bonding optical members. For example, a transparent adhesive sheet is used for bonding a touch panel and various display members and optical members (see, for example, Patent Document 1).

JP, 2011-99073, A

  In particular, in recent years, an optical product having a touch panel such as a smartphone has been mainly of a capacitance type. In this case, in order to improve the visibility of the display device, the optical product is conventionally The full lamination technology which fills up the space which used to be with the above-mentioned adhesive sheet, and eliminates space has come to be adopted.

  In the field of on-vehicle optical products, such as car navigation systems, those of the capacitance type are emerging. However, no on-vehicle optical products have adopted the above-mentioned full lamination technology. In addition, in the in-vehicle optical products, the space (sometimes referred to as "air gap") existing in the optical products is larger than that of a smartphone or the like, and the above adhesive sheet can not be used. . For this reason, when sticking the optical member used for a vehicle-mounted optical product, the adhesive sheet with favorable bonding property is calculated | required.

  In addition, in optical products for vehicles, a plastic cover is often used around the air gap. Since the interior of the vehicle may be in a high temperature environment, there are cases where adhesion reliability is insufficient such that bubbles are generated or peeled off in the adhesive sheet due to the high temperature of the in-vehicle optical product. For this reason, when the air gap in the optical product for vehicles was filled up with an adhesive sheet, the adhesive sheet with high adhesion reliability might be called for, even if stuck on plastic materials, such as a plastic cover.

  Accordingly, an object of the present invention is to provide a pressure-sensitive adhesive sheet having a good bonding property when used in an on-vehicle optical product. Another object of the present invention is to provide a pressure-sensitive adhesive sheet having high adhesion reliability when used in an on-vehicle optical product.

  MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to achieve the said objective, this inventor is a double-sided adhesive sheet which has an adhesive layer, Comprising: The thickness for a said double-sided adhesive sheet is 500 micrometers or more. By setting it as an adhesive sheet, it discovers that an adhesive sheet with favorable bonding property can be obtained, and completed this invention.

  That is, the present invention provides a double-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer, wherein the double-sided pressure-sensitive adhesive sheet has a thickness of 500 μm or more and is used for an on-vehicle optical product. .

  The optical double-sided pressure-sensitive adhesive sheet preferably has a pressure-sensitive adhesive layer on both sides of the substrate.

  The thickness of the substrate is preferably 75 μm or more.

The optical double-sided pressure-sensitive adhesive sheet preferably has at least a pressure-sensitive adhesive layer having an elastic modulus of 4.0 × 10 ⁴ Pa or more at 95 ° C.

  The in-plane retardation of the substrate is preferably 4000 nm or more.

  Moreover, this invention provides the vehicle-mounted optical product which has the said double-sided adhesive sheet for optics.

  The optical double-sided pressure-sensitive adhesive sheet of the present invention has good bonding properties when used in an on-vehicle optical product. Therefore, it is possible to obtain an on-vehicle optical product in which the full lamination technology is adopted. Moreover, the optical product for vehicles excellent in visibility can be obtained.

It is a schematic sectional drawing which shows an example of the vehicle-mounted optical product in which the double-sided adhesive sheet for optics of this invention was used. It is a schematic sectional drawing which shows another example of the vehicle-mounted optical product in which the double-sided adhesive sheet for optics of this invention was used. It is a top view of the lower glass used for evaluation of the bonding property of a double-sided adhesive sheet. It is sectional drawing (A-A 'line sectional view of FIG. 3) of lower glass used for evaluation of the bondability of a double-sided adhesive sheet. It is sectional drawing (line B-B 'sectional view of FIG. 3) of the lower glass used for evaluation of the bonding property of a double-sided adhesive sheet.

  The optical double-sided pressure-sensitive adhesive sheet of the present invention may be a so-called "substrate-less type" pressure-sensitive adhesive sheet not having a substrate (substrate layer), or a pressure-sensitive adhesive sheet having a substrate Good. In the present specification, a "substrate-less type" adhesive sheet may be referred to as a "substrate-less adhesive sheet", and a type having a substrate may be referred to as a "substrate-attached pressure-sensitive adhesive sheet". is there. Among them, in the optical double-sided pressure-sensitive adhesive sheet of the present invention, the thickness of the pressure-sensitive adhesive layer can be made relatively thin while securing the thickness of the pressure-sensitive adhesive sheet, whereby the formation of the pressure-sensitive adhesive layer can be made easier. Therefore, a substrate-attached pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on both sides of the substrate is preferable. In the present specification, the term "pressure-sensitive adhesive sheet" also includes tape-like ones, that is, "pressure-sensitive adhesive tapes".

  The thickness of the optical double-sided pressure-sensitive adhesive sheet of the present invention is 500 μm or more, preferably more than 500 μm, more preferably 550 μm or more, and still more preferably 600 μm or more. When the thickness is 500 μm or more, the double-sided pressure-sensitive adhesive sheet for optics of the present invention has good adhesion when used in an optical product for use in vehicles. The upper limit of the thickness is not particularly limited, but is preferably 3000 μm or less, more preferably 2500 μm or less, still more preferably 2000 μm or less, and particularly preferably 1500 μm or less. The thickness of the optical double-sided pressure-sensitive adhesive sheet of the present invention does not include the thickness of the below-described release liner. Therefore, when the optical double-sided pressure-sensitive adhesive sheet of the present invention is a substrate-less pressure-sensitive adhesive sheet, the thickness of the pressure-sensitive adhesive sheet is the distance from one surface to the other surface of the pressure-sensitive adhesive layer. When the sheet is a substrate-attached pressure-sensitive adhesive sheet, the thickness of the pressure-sensitive adhesive sheet is from the surface of the pressure-sensitive adhesive layer provided on one side of the substrate to the surface of the pressure-sensitive adhesive layer provided on the other side of the substrate It is a distance.

(Pressure-sensitive adhesive layer)
The optical double-sided pressure-sensitive adhesive sheet of the present invention has at least one pressure-sensitive adhesive layer. The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is not particularly limited, but, for example, acrylic pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives, vinyl alkyl ether-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, polyester-based pressure-sensitive adhesives, polyamide-based pressure-sensitive adhesives And urethane-based pressure-sensitive adhesives, fluorine-based pressure-sensitive adhesives, epoxy-based pressure-sensitive adhesives and the like. Among them, as the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer, an acrylic pressure-sensitive adhesive is preferable from the viewpoint of transparency, tackiness, weather resistance, cost, and easiness of design of the pressure-sensitive adhesive. That is, it is preferable that the said adhesive layer is an acrylic adhesive layer comprised from the acrylic adhesive. The above-mentioned adhesives can be used alone or in combination of two or more.

  The acrylic pressure-sensitive adhesive layer contains an acrylic polymer as a base polymer. The said acryl-type polymer is a polymer which contains an acryl-type monomer (monomer which has a (meth) acryloyl group in a molecule | numerator) as a monomer component which comprises a polymer. It is preferable that the said acryl-type polymer is a polymer which contains a (meth) acrylic-acid alkylester as a monomer component which comprises a polymer. In addition, an acryl-type polymer can be used individually or in combination of 2 or more types.

  The pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer may be in any form. For example, the pressure-sensitive adhesive composition may be of an emulsion type, a solvent type (solution type), an active energy ray curing type, a heat melting type (hot melt type) or the like. Among them, solvent-type and active energy ray-curable pressure-sensitive adhesive compositions are preferable from the viewpoint of productivity and that a pressure-sensitive adhesive layer excellent in optical characteristics and appearance is easily obtained, and in particular, active energy ray-curable pressure-sensitive adhesive compositions Are preferred. It is preferable for the pressure-sensitive adhesive composition to be an active energy ray-curable pressure-sensitive adhesive composition, since a sufficiently-cured pressure-sensitive adhesive layer can be easily obtained even if it is a relatively thick pressure-sensitive adhesive layer.

  Examples of the active energy ray include ionizing radiation such as alpha rays, beta rays, gamma rays, neutron rays, and electron rays, and ultraviolet rays. Particularly, ultraviolet rays are preferable. That is, the active energy ray-curable pressure-sensitive adhesive layer is preferably a UV-curable pressure-sensitive adhesive layer.

  That is, the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive layer containing an acrylic polymer as a base polymer, and is preferably formed of an active energy ray-curable acrylic pressure-sensitive adhesive composition.

  Examples of the acrylic pressure-sensitive adhesive composition include an acrylic pressure-sensitive adhesive composition containing an acrylic polymer as an essential component, and a mixture of monomers (monomers) constituting the acrylic polymer ("monomer mixture"). And (ii) an acrylic pressure-sensitive adhesive composition containing the partially polymerized product as an essential component. Examples of the former include so-called solvent-type acrylic pressure-sensitive adhesive compositions and the like. Also. Examples of the latter include so-called active energy ray-curable pressure-sensitive adhesive compositions. The above-mentioned "monomer mixture" means a mixture consisting of only monomer components constituting a polymer. Moreover, the said "partially polymerized material" may also be called a "prepolymer", and means the composition to which the one or two or more component is partially polymerized among the components of the said monomer mixture.

  The acrylic polymer is a polymer composed (formed) of an acrylic monomer as an essential monomer component (monomer component). It is preferable that the said acryl-type polymer is a polymer comprised (formed) by using (meth) acrylic-acid alkylester as an essential monomer component. That is, it is preferable that the said acryl-type polymer contains (meth) acrylic-acid alkylester as a structural unit. In the present specification, the term "(meth) acrylic" refers to "acrylic" and / or "methacrylic" (any one or both of "acrylic" and "methacrylic"), and so forth. In addition, the said acryl-type polymer is comprised by 1 type, or 2 or more types of monomer components.

  As said (meth) acrylic-acid alkylester as an essential monomer component, the (meth) acrylic-acid alkylester which has a linear or branched alkyl group is mentioned preferably. In addition, (meth) acrylic-acid alkylester can be used individually or in combination of 2 or more types.

  The (meth) acrylic acid alkyl ester having a linear or branched alkyl group is not particularly limited, and examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, Isopropyl acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, (meth) Isopentyl acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, (meth) ) Isononyl acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, (Meth) acrylate undecyl, (meth) acrylate dodecyl, (meth) acrylate tridecyl, (meth) acrylate tetradecyl, (meth) acrylate pentadecyl, (meth) acrylate hexadecyl, (meth) acrylate heptadecyl, (meth) ) A linear or branched alkyl group having 1 to 20 carbon atoms such as octadecyl acrylate (stearyl (meth) acrylate), isostearyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate and the like And (meth) acrylic acid alkyl esters. Among them, the (meth) acrylic acid alkyl ester having a linear or branched alkyl group is preferably a (meth) acrylic acid alkyl ester having a linear or branched alkyl group having 4 to 18 carbon atoms. And more preferably 2-ethylhexyl acrylate (2EHA), n-butyl acrylate (BA) and isostearyl acrylate (ISTA). From the viewpoint of further improving the adhesion reliability to the plastic material, the (meth) acrylic acid alkyl ester having the above linear or branched alkyl group is a linear or branched C4 to C10 among others. (Meth) acrylic acid alkyl esters having a linear alkyl group are preferred, and more preferred are 2-ethylhexyl acrylate (2EHA) and n-butyl acrylate (BA). Moreover, the (meth) acrylic acid alkyl ester having a linear or branched alkyl group can be used alone or in combination of two or more.

  The proportion of the (meth) acrylic acid alkyl ester in all the monomer components (100% by weight) constituting the above acrylic polymer is not particularly limited, but is 50% by weight or more (eg, 50 to 100% by weight) Is more preferably 53 to 90% by weight, still more preferably 55 to 85% by weight.

  The said acryl-type polymer may contain the copolymerizable monomer with the said (meth) acrylic-acid alkylester as a monomer component which comprises a polymer. That is, the said acryl-type polymer may contain the copolymerizable monomer as a structural unit. In addition, a copolymerizable monomer can be used individually or in combination of 2 or more types.

  The above-mentioned copolymerizable monomer is not particularly limited, but from the viewpoint of suppression of clouding and improvement of durability under high humidity environment, adhesion reliability, compatibility with various additives, transparency, molecular nitrogen A monomer having an atom and a monomer having a hydroxyl group in the molecule are preferably mentioned. That is, it is preferable that the said acryl-type polymer contains the monomer which has a nitrogen atom in a molecule | numerator as a structural unit. Moreover, it is preferable that the said acryl-type polymer contains the monomer which has a hydroxyl group in a molecule | numerator as a structural unit.

  The monomer having a nitrogen atom in the molecule is a monomer (monomer) having at least one nitrogen atom in the molecule (within one molecule). In the present specification, the above-mentioned "monomer having a nitrogen atom in the molecule" may be referred to as "nitrogen atom-containing monomer". Although it does not specifically limit as said nitrogen atom containing monomer, A cyclic nitrogen containing monomer, (meth) acrylamides, etc. are mentioned preferably. In addition, a nitrogen atom containing monomer can be used individually or in combination of 2 or more types.

  The cyclic nitrogen-containing monomer is not particularly limited as long as it has a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and has a cyclic nitrogen structure. The cyclic nitrogen structure preferably has a nitrogen atom in the cyclic structure.

  Examples of the cyclic nitrogen-containing monomer include N-vinyl cyclic amide (lactam vinyl monomer), and vinyl monomers having a nitrogen-containing heterocyclic ring.

（式（１）中、Ｒ¹は２価の有機基を示す） As said N-vinyl cyclic amide, N-vinyl cyclic amide represented by following formula (1) is mentioned, for example.

(In formula (1), R ¹ represents a divalent organic group)

R ¹ in the above formula (1) is a divalent organic group, preferably a divalent saturated hydrocarbon group or an unsaturated hydrocarbon group, and more preferably a divalent saturated hydrocarbon group (eg, carbon number 3-5 alkylene groups, etc.).

  As the N-vinyl cyclic amide represented by the above formula (1), for example, N-vinyl-2-pyrrolidone, N-vinyl-2-piperidone, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam , N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholindione, and the like.

  Examples of the vinyl-based monomer having a nitrogen-containing heterocycle include acrylic monomers having a nitrogen-containing heterocycle such as morpholine ring, piperidine ring, pyrrolidine ring, and piperazine ring.

  The vinyl-based monomer having a nitrogen-containing heterocycle is not particularly limited, and examples thereof include (meth) acryloyl morpholine, N-vinyl piperazine, N-vinyl pyrrole, N-vinyl imidazole, N-vinyl pyrazine and N-vinyl morpholine. , N-vinylpyrazole, vinylpyridine, vinylpyrimidine, vinyloxazole, vinylisoxazole, vinylthiazole, vinylisothiazole, vinylpyridazine, (meth) acryloyl pyrrolidone, (meth) acryloyl pyrrolidine, (meth) acryloyl piperidine and the like. .

  Among the vinyl monomers having a nitrogen-containing heterocycle, acrylic monomers having a nitrogen-containing heterocycle are preferable, and (meth) acryloyl morpholine, (meth) acryloyl pyrrolidine, and (meth) acryloyl piperidine are more preferable.

  Examples of the (meth) acrylamides include (meth) acrylamide, N-alkyl (meth) acrylamide, N, N-dialkyl (meth) acrylamide and the like. Examples of the N-alkyl (meth) acrylamide include N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-n-butyl (meth) acrylamide, N-octyl (meth) acrylamide and the like. . Furthermore, the above-mentioned N-alkyl (meth) acrylamide also includes (meth) acrylamide having an amino group such as dimethylaminoethyl (meth) acrylamide, diethylaminoethyl (meth) acrylamide, and dimethylaminopropyl (meth) acrylamide. Examples of the N, N-dialkyl (meth) acrylamides include N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dipropyl (meth) acrylamide, N, N-diisopropyl (Meth) acrylamide, N, N-di (n-butyl) (meth) acrylamide, N, N-di (t-butyl) (meth) acrylamide and the like can be mentioned.

  The (meth) acrylamides also include, for example, various N-hydroxyalkyl (meth) acrylamides. Examples of the N-hydroxyalkyl (meth) acrylamide include N-methylol (meth) acrylamide, N- (2-hydroxyethyl) (meth) acrylamide, N- (2-hydroxypropyl) (meth) acrylamide, N- (1-hydroxypropyl) (meth) acrylamide, N- (3-hydroxypropyl) (meth) acrylamide, N- (2-hydroxybutyl) (meth) acrylamide, N- (3-hydroxybutyl) (meth) acrylamide, N- (4-hydroxybutyl) (meth) acrylamide, N-methyl-N-2-hydroxyethyl (meth) acrylamide and the like can be mentioned.

  The (meth) acrylamides also include, for example, various N-alkoxyalkyl (meth) acrylamides. As said N- alkoxyalkyl (meth) acrylamide, N- methoxymethyl (meth) acrylamide, N- butoxymethyl (meth) acrylamide etc. are mentioned, for example.

  Moreover, as a nitrogen atom containing monomer other than the said cyclic nitrogen containing monomer and said (meth) acrylamides, an amino group containing monomer, a cyano group containing monomer, an imide group containing monomer, an isocyanate group containing monomer etc. are mentioned, for example. Examples of the amino group-containing monomer include aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate. . Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile. Examples of the imide group-containing monomers include maleimide monomers (eg, N-cyclohexyl maleimide, N-isopropyl maleimide, N-lauryl maleimide, N-phenyl maleimide, etc.), itaconimide monomers (eg, N-methyl itaconimide, N- Ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-laurylitaconimide, N-cyclohexylitaconimide, etc., succinimide monomers (eg, N- (meth) acryloylyl) And oxymethylene succinimide, N- (meth) acryloyl-6-oxyhexamethylene succinimide, N- (meth) acryloyl-8-oxyoctamethylene succinimide and the like. As said isocyanate group containing monomer, 2- (meth) acryloyl oxyethyl isocyanate etc. are mentioned, for example.

  Among them, as the nitrogen atom-containing monomer, cyclic nitrogen-containing monomers are preferable, and N-vinyl cyclic amide is more preferable. More specifically, N-vinyl-2-pyrrolidone (NVP) is particularly preferred.

  When the acrylic polymer contains the nitrogen atom-containing monomer as a monomer component that constitutes the polymer, the ratio of the nitrogen atom-containing monomer in all the monomer components (100% by weight) that constitutes the acrylic polymer is The content is not particularly limited, but is preferably 1% by weight or more, more preferably from the viewpoint of obtaining a pressure-sensitive adhesive layer excellent in adhesiveness, suppression of clouding in a high humidity environment and improvement of durability, and adhesion reliability. Is 3% by weight or more, more preferably 5% by weight or more. The upper limit of the ratio of the nitrogen atom-containing monomer is preferably 30% by weight or less, more preferably 25% by weight, from the viewpoint of obtaining a pressure-sensitive adhesive layer having appropriate flexibility and a pressure-sensitive adhesive layer having excellent transparency. % Or less, more preferably 20% by weight or less.

  The monomer having a hydroxyl group in the molecule is a monomer having at least one hydroxyl group (hydroxyl group) in the molecule (in one molecule), and polymerization having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group Preferred are those having a functional group and having a hydroxyl group. However, the above-described nitrogen atom-containing monomer is not included in the above-described monomer having a hydroxyl group in the molecule. That is, in the present specification, a monomer having both a nitrogen atom and a hydroxyl group in the molecule is included in the above "nitrogen atom-containing monomer". In the present specification, the above-mentioned "monomer having a hydroxyl group in the molecule" may be referred to as "hydroxy group-containing monomer". In addition, a hydroxyl-containing monomer can be used individually or in combination of 2 or more types.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, (Meth) acrylic acid 6-hydroxyhexyl, (meth) acrylic acid hydroxyoctyl, (meth) acrylic acid hydroxydecyl, (meth) acrylic acid hydroxy lauryl, (meth) acrylic acid (4-hydroxymethylcyclohexyl), etc. Meta) acrylic acid ester; vinyl alcohol; allyl alcohol etc. are mentioned.

  Among them, as the above-mentioned hydroxyl group-containing monomer, a hydroxyl group-containing (meth) acrylic acid ester is preferable, and more preferable are 2-hydroxyethyl acrylate (HEA) and 4-hydroxybutyl acrylate (4HBA).

  When the acrylic polymer contains the hydroxyl group-containing monomer as a monomer component constituting the polymer, the proportion of the hydroxyl group-containing monomer in the total monomer component (100% by weight) constituting the acrylic polymer is particularly limited. Although not preferred, it is preferably 0.5% by weight or more, more preferably 0.8% by weight or more, from the viewpoint of suppression of clouding in a high humidity environment and improvement of durability, and adhesion reliability. More preferably, it is 1% by weight or more. The upper limit of the proportion of the hydroxyl group-containing monomer is preferably 30% by weight or less, more preferably 25% by weight or less, from the viewpoint of obtaining appropriate cohesion and suppressing the transparency and dielectric constant to a low level. And more preferably 20% by weight.

  The total of the proportions of the nitrogen atom-containing monomer and the hydroxyl group-containing monomer in the total monomer components (100% by weight) constituting the acrylic polymer is not particularly limited, but the suppression of white turbidity in a high humidity environment From the viewpoint of improving durability and obtaining adhesion reliability, the content is preferably 5% by weight or more, more preferably 10% by weight or more, and still more preferably 15% by weight or more. The upper limit of the sum of the above proportions is preferably 50% by weight or less, more preferably 40% by weight, from the viewpoint of obtaining a pressure-sensitive adhesive layer having appropriate flexibility and a pressure-sensitive adhesive layer having excellent transparency. % Or less, more preferably 35% by weight or less.

  Examples of the copolymerizable monomer other than the nitrogen atom-containing monomer and the hydroxyl group-containing monomer further include an alicyclic structure-containing monomer. The above-mentioned alicyclic structure-containing monomer is not particularly limited as long as it has a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and has an alicyclic structure. For example, an alkyl (meth) acrylate having a cycloalkyl group is included in the above alicyclic structure-containing monomer. In addition, an alicyclic structure containing monomer can be used individually or in combination of 2 or more types.

  The alicyclic structure in the alicyclic structure-containing monomer is a cyclic hydrocarbon structure and preferably has 5 or more carbon atoms, more preferably 5 to 24 carbon atoms, and still more preferably 6 to 15 carbon atoms, 6 to 10 are particularly preferred.

Examples of the alicyclic structure-containing monomer include cyclopropyl (meth) acrylate, cyclobutyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cycloheptyl (meth) acrylate, cyclooctyl (meth) acrylate, Isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, HPMPA represented by the following formula (2), TMA-2 represented by the following formula (3), HCPA represented by the following formula (4), etc. And (meth) acrylic monomers. Among these, cyclohexyl acrylate (CHA) is preferable.

  When the above-mentioned acrylic polymer contains the above-mentioned alicyclic structure-containing monomer as a monomer component which constitutes a polymer, the ratio of the above-mentioned alicyclic structure-containing monomer in all the monomer components (100% by weight) which constitutes the above-mentioned acrylic polymer Is not particularly limited, but is preferably 10% by weight or more from the viewpoint of improving durability and achieving adhesion reliability. Moreover, it is preferable that the upper limit of the ratio of the said alicyclic structure containing monomer is 50 weight% or less from the point which obtains the adhesive layer which has moderate softness | flexibility.

  Furthermore, as a copolymerizable monomer, a polyfunctional monomer is mentioned, for example. Examples of the polyfunctional monomer include hexanediol di (meth) acrylate, butanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl Glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylol methane tri (meth) acrylate, And allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate and the like. In addition, a polyfunctional monomer can be used individually or in combination of 2 or more types.

  When the acrylic polymer contains the polyfunctional monomer as a monomer component constituting the polymer, the ratio of the polyfunctional monomer to the total monomer component (100% by weight) constituting the acrylic polymer is particularly Although not limited, it is preferably 0.5% by weight or less (eg, more than 0% by weight and 0.5% by weight or less), more preferably 0.1% by weight or less (eg, more than 0% by weight) % Or less).

  Moreover, (meth) acrylic acid alkoxy alkyl ester is mentioned as said copolymerizable monomer. The (meth) acrylic acid alkoxyalkyl ester is not particularly limited, and examples thereof include 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, Examples thereof include 3-methoxypropyl methacrylate, 3-ethoxypropyl (meth) acrylate, 4-methoxybutyl (meth) acrylate, 4-ethoxybutyl (meth) acrylate and the like. Among them, the (meth) acrylic acid alkoxyalkyl ester is preferably an acrylic acid alkoxyalkyl ester, and more preferably 2-methoxyethyl acrylic acid (MEA). In addition, the said (meth) acrylic acid alkoxy alkyl ester can be used individually or in combination of 2 or more types.

  When the above acrylic polymer contains the above (meth) acrylic acid alkoxyalkyl ester as a monomer component constituting the polymer, the ratio of the above (meth) acrylic acid alkyl ester to the above (meth) acrylic acid alkoxyalkyl ester is Although not particularly limited, in the [former: latter] (weight ratio), 100: 0 to 25:75 is preferable, and more preferably 100: 0 to 50:50.

  In addition, as the above-mentioned copolymerizable monomer, for example, a carboxyl group-containing monomer, an epoxy group-containing monomer, a sulfonic acid group-containing monomer, a phosphoric acid group-containing monomer, (meth) acrylic acid ester having an aromatic hydrocarbon group, And vinyl esters, aromatic vinyl compounds, olefins or dienes, vinyl ethers, vinyl chloride and the like. Examples of the carboxyl group-containing monomer include (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid and the like, and examples of the carboxyl group-containing monomer include maleic anhydride. Also included are acid anhydride group-containing monomers such as itaconic anhydride. Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate. Examples of the sulfonic acid group-containing monomer include sodium vinyl sulfonate and the like. Examples of the (meth) acrylic acid ester having an aromatic hydrocarbon group include phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, and benzyl (meth) acrylate. Examples of the vinyl esters include vinyl acetate and vinyl propionate. Examples of the aromatic vinyl compound include styrene and vinyl toluene. Examples of the above-mentioned olefins or dienes include ethylene, propylene, butadiene, isoprene and isobutylene. As said vinyl ether, a vinyl alkyl ether etc. are mentioned, for example.

  The above-mentioned acrylic polymer preferably contains no or substantially no acidic group-containing monomer as a monomer component constituting the polymer, from the viewpoint of obtaining an acrylic pressure-sensitive adhesive layer having an excellent corrosion prevention effect, and particularly preferably a carboxyl group. It is preferred not to contain substantially or to contain a containing monomer. When the acrylic pressure-sensitive adhesive layer has an excellent corrosion prevention effect, the acrylic pressure-sensitive adhesive layer chemically bonds to the optical member when the acrylic pressure-sensitive adhesive layer contacts the optical member as an adherend in the optical product. It is possible to suppress the damage to the appearance and the function of the optical member by acting. As an acidic group containing monomer, a carboxyl group containing monomer, a sulfonic acid group containing monomer, a phosphoric acid group containing monomer etc. are mentioned, for example. Specifically, the proportion of the acidic group-containing monomer in all the monomer components (100% by weight) constituting the above acrylic polymer is 0.05% by weight or less (preferably 0.01% by weight or less) Can be said to be substantially free.

  Among the above-mentioned acrylic polymers, 50 to 90% by weight (preferably 55 to 85% by weight) of (meth) acrylic acid alkyl ester having a linear or branched alkyl group having 4 to 18 carbon atoms An acrylic polymer composed of a monomer component containing 10 to 50% by weight (preferably 15 to 45% by weight) of one or more monomers selected from the group consisting of nitrogen atom-containing monomers and hydroxyl group-containing monomers 50 to 90% by weight (preferably 55 to 75% by weight) of a (meth) acrylic acid alkyl ester having a linear or branched alkyl group having 4 to 10 carbon atoms, a nitrogen atom-containing monomer and a hydroxyl group 10 to 47% by weight (preferably 15 to 45% by weight) of one or more monomers selected from the group consisting of containing monomers, and having 6 to 6 carbon atoms 0 alicyclic structure-containing monomer 0 to 40% by weight and more preferably an acrylic polymer composed of (preferably 0 to 30 wt%) containing a monomer component. In addition, the said content (weight%) is content with respect to all the monomer components (100 weight%) which comprise an acryl-type polymer.

  The base polymer such as the acrylic polymer contained in the pressure-sensitive adhesive layer is obtained by polymerizing monomer components. The polymerization method is not particularly limited, and examples thereof include a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, and a polymerization method by active energy ray irradiation (active energy ray polymerization method). Among them, the solution polymerization method and the active energy ray polymerization method are preferable, and the active energy ray polymerization method is more preferable, from the viewpoint of the transparency of the pressure-sensitive adhesive layer, cost and the like.

  Moreover, various common solvents may be used in the case of superposition | polymerization of said monomer component. Examples of the solvent include esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; cyclohexane, methylcyclohexane and the like Aliphatic hydrocarbons; organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone; In addition, a solvent can be used individually or in combination of 2 or more types.

  At the time of the polymerization of the above-mentioned monomer components, a polymerization initiator such as a thermal polymerization initiator or a photopolymerization initiator (photoinitiator) may be used depending on the type of polymerization reaction. In addition, a polymerization initiator can be used individually or in combination of 2 or more types.

  The thermal polymerization initiator is not particularly limited, but, for example, an azo polymerization initiator, a peroxide polymerization initiator (eg, dibenzoyl peroxide, tert-butyl permaleate, etc.), a redox polymerization initiator, etc. Can be mentioned. Among them, the azo polymerization initiator disclosed in JP-A-2002-69411 is preferable. As the above-mentioned azo polymerization initiator, 2,2'-azobisisobutyronitrile (hereinafter sometimes referred to as "AIBN"), 2,2'-azobis-2-methylbutyronitrile (hereinafter referred to as " And the like), dimethyl 2,2'-azobis (2-methylpropionate), 4,4'-azobis-4-cyanovaleric acid and the like. In addition, a thermal-polymerization initiator can be used individually or in combination of 2 or more types.

  When the azo polymerization initiator is used in the polymerization of the acrylic polymer, the amount of the thermal polymerization initiator used is not particularly limited. For example, 100 parts by weight of all the monomer components constituting the acrylic polymer are used. The amount is preferably 0.05 parts by weight or more, more preferably 0.1 parts by weight or more, and preferably 0.5 parts by weight or less, more preferably 0.3 parts by weight or less It is.

The photopolymerization initiator is not particularly limited. For example, benzoin ether photopolymerization initiator, acetophenone photopolymerization initiator, α-ketol photopolymerization initiator, aromatic sulfonyl chloride photopolymerization initiator, light An active oxime type photoinitiator, a benzoin type photoinitiator, a benzyl type photoinitiator, a benzophenone series type photoinitiator, a ketal type photoinitiator, a thioxanthone type photoinitiator, etc. are mentioned. In addition, an acyl phosphine oxide type photoinitiator and a titanocene type photoinitiator are mentioned. Examples of the above-mentioned benzoin ether photopolymerization initiators include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-one, Anisole methyl ether etc. are mentioned. Examples of the acetophenone-based photopolymerization initiators include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 4-phenoxydichloroacetophenone, 4- (t-butyl) ) Dichloroacetophenone and the like. Examples of the α-ketol photopolymerization initiator include 2-methyl-2-hydroxypropiophenone, 1- [4- (2-hydroxyethyl) phenyl] -2-methylpropan-1-one and the like. Be As said aromatic sulfonyl chloride type photoinitiator, 2-naphthalene sulfonyl chloride etc. are mentioned, for example. Examples of the photoactive oxime-based photopolymerization initiator include 1-phenyl-1,1-propanedione-2- (O-ethoxycarbonyl) -oxime and the like. Examples of the benzoin photopolymerization initiator include benzoin. As said benzyl type photoinitiator, a benzyl etc. are mentioned, for example. Examples of the benzophenone-based photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinyl benzophenone, α-hydroxycyclohexyl phenyl ketone and the like. As said ketal type photoinitiator, a benzyl dimethyl ketal etc. are mentioned, for example. Examples of the thioxanthone photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methyl thioxanthone, 2,4-dimethyl thioxanthone, isopropyl thioxanthone, 2,4-diisopropyl thioxanthone, and dodecyl thioxanthone. Examples of the acyl phosphine oxide photopolymerization initiator include 2,4,6-trimethyl benzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethyl benzoyl) -phenyl phosphine oxide and the like. . Examples of the titanocene photopolymerization initiators include bis (( ⁵ -2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -phenyl And titanium). In addition, a photoinitiator can be used individually or in combination of 2 or more types.

  When using the said photoinitiator in the case of superposition | polymerization of the said acryl-type polymer, although the usage-amount of the said photopolymerization initiator is not specifically limited, For example, 100 weight part of all the monomer components which comprise the said acryl-type polymer The amount is preferably 0.01 parts by weight or more, more preferably 0.1 parts by weight or more, and preferably 3 parts by weight or less, more preferably 1.5 parts by weight or less.

  The pressure-sensitive adhesive layer may contain an ultraviolet absorber (UVA). In addition, an ultraviolet absorber can be used individually or in combination of 2 or more types.

  The UV absorber is not particularly limited. For example, benzotriazole-based UV absorber, hydroxyphenyltriazine-based UV absorber, salicylic acid ester-based UV absorber, benzophenone-based UV absorber, oxybenzophenone-based UV absorber, cyano An acrylate type ultraviolet absorber etc. are mentioned.

  As a benzotriazole type ultraviolet absorber (benzotriazole type compound), for example, 2- (2-hydroxy-5-tert-butylphenyl) -2H-benzotriazole (trade name "TINUVIN PS", manufactured by BASF), benzene Ester compound of propanoic acid and 3- (2H-benzotriazol-2-yl) -5- (1,1-dimethylethyl) -4-hydroxy (C7-9 side chain and straight chain alkyl) (brand name “TINUVIN 384 -2, BASF AG), octyl 3- [3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate and 2-ethylhexyl-3- [ 3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazole) Mixture of (2- yl) phenyl] propionate (trade name "TINUVIN 109", manufactured by BASF Corp.), 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) ) Phenol (trade name “TINUVIN 900”, manufactured by BASF Corp.), 2- (2H-benzotriazol-2-yl) -6- (1-methyl-1-phenylethyl) -4- (1,1,3,3) 3-Tetramethylbutyl) phenol (trade name “TINUVIN 928”, manufactured by BASF), methyl 3- (3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate / polyethylene Reaction product of glycol 300 (trade name “TINUVIN 1130”, manufactured by BASF), 2- (2H-benzotri) Zol-2-yl) -p-cresol (trade name “TINUVIN P”, manufactured by BASF AG), 2 (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) Phenol (trade name "TINUVIN 234", manufactured by BASF Corporation), 2- [5-chloro-2H-benzotriazol-2-yl] -4-methyl-6- (tert-butyl) phenol (trade name "TINUVIN 326" Manufactured by BASF, 2- (2H-benzotriazol-2-yl) -4,6-di-tert-pentylphenol (trade name "TINUVIN 328" manufactured by BASF), 2- (2H-benzotriazole) 2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol (trade name "TINUVIN 329", manufactured by BASF) 2,2'-methylenebis [6- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol] (trade name "TINUVIN 360", manufactured by BASF Corporation), Reaction product of methyl 3- (3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate and polyethylene glycol 300 (trade name "TINUVIN 213", manufactured by BASF) 2- (2H-benzotriazol-2-yl) -6-dodecyl-4-methylphenol (trade name “TINUVIN 571”, manufactured by BASF), 2- [2-hydroxy-3- (3,4,5) , 6-Tetrahydrophthalimido-methyl) -5-methylphenyl] benzotriazole (trade name "Sumisorb 250" Sumitomo Chemical Co., Ltd., 2,2'-Methylenebis [6- (2H-benzotriazol-2-yl) -4-tert-octylphenol] (trade name "ADEKA Stub LA-31", manufactured by ADEKA Co., Ltd.), etc. Can be mentioned.

As a hydroxyphenyl triazine type ultraviolet absorber (hydroxyphenyl triazine type compound), for example, 2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl) -5 -Reaction product of-hydroxyphenyl and [(C10-C16 (mainly C12-C13) alkyloxy) methyl] oxirane (trade name "TINUVIN 400", manufactured by BASF), 2- [4, 6-bis (2, 4-dimethylphenyl) -1,3,5-triazin-2-yl] -5- [3- (dodecyloxy) -2-hydroxypropoxy] phenol), 2- (2,4-dihydroxyphenyl) -4, Reaction product of 6-bis- (2,4-dimethylphenyl) -1,3,5-triazine and (2-ethylhexyl) -glycidic acid ester ( Trade name "TINUVIN 405" (manufactured by BASF AG), 2,4-bis (2-hydroxy-4-butoxyphenyl) -6- (2,4-dibutoxyphenyl) -1,3,5-triazine (trade name) "TINUVIN 460" (manufactured by BASF), 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol (trade name "TINUVIN 1577", BASF AG), 2- (4,6-Diphenyl-1,3,5-triazin-2-yl) -5- [2- (2-ethylhexanoyloxy) ethoxy] -phenol (trade name: Adekastab LA) -46 ", manufactured by ADEKA Co., Ltd.), 2- (2-hydroxy-4- [1-octyloxycarbonylethoxy] phenyl) -4,6-bis (4-phenylphenyl)- 1, 3, 5- triazine (brand name "TINUVIN 479, BASF company make) etc. are mentioned. Other than the above, a compound represented by the following formula (5) (trade name “TINUVIN 477”, manufactured by BASF Corporation) can be mentioned.

  Examples of benzophenone-based ultraviolet absorbers (benzophenone-based compounds) and oxybenzophenone-based ultraviolet absorbers (oxybenzophenone-based compounds) include, for example, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, and 2-hydroxy-4-methoxybenzophenone. Methoxybenzophenone-5-sulfonic acid (anhydrous and trihydrate), 2-hydroxy-4-octyloxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 4-benzyloxy-2-hydroxybenzophenone, 2,2'- Dihydroxy-4-methoxybenzophenone (trade name "KEMISORB 111", manufactured by Chemi-Pro Chemical Co., Ltd.), 2,2 ', 4,4'-tetrahydroxybenzophenone (trade name "SEESORB 106", manufactured by Shiprokasei Co., Ltd.) 2,2'-dihydroxy-4,4'-dimethoxy benzophenone.

  As a salicylic acid ester type ultraviolet absorber (salicylic acid ester type compound), for example, phenyl 2-acryloyloxybenzoate, phenyl 2-acroyloxy-3-methylbenzoate, phenyl 2-acryloyloxy-4-methylbenzoate, phenyl 2-acryloyloxybenzoate. Acrylyloxy-5-methylbenzoate, phenyl 2-acryloyloxy-3-methoxybenzoate, phenyl 2-hydroxybenzoate, phenyl 2-hydroxy-3-methylbenzoate, phenyl 2-hydroxy-4-methylbenzoate, phenyl 2-hydroxy- 5-methylbenzoate, phenyl 2-hydroxy-3-methoxybenzoate, 2,4-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzo Over door (trade name "TINUVIN 120", manufactured by BASF), and the like.

  As a cyanoacrylate type ultraviolet absorber (cyanoacrylate type compound), for example, alkyl 2-cyanoacrylate, cycloalkyl 2-cyanoacrylate, alkoxyalkyl 2-cyanoacrylate, alkenyl 2-cyanoacrylate, alkynyl 2-cyanoacrylate and the like It can be mentioned.

  Benzotriazole-based ultraviolet light from the viewpoint of having excellent optical properties, high transparency, and excellent light stability while having high ultraviolet absorptivity as the above-mentioned ultraviolet light absorber At least one UV absorber selected from the group consisting of an absorber, a benzophenone type UV absorber, and a hydroxyphenyltriazine type UV absorber is preferred, and a benzotriazole type UV absorber is more preferred. In particular, a benzotriazole-based ultraviolet absorber is preferable in which a phenyl group having a carbon number of 6 or more and a hydroxyl group as a substituent is bonded to a nitrogen atom constituting a benzotriazole ring.

Moreover, it is preferable that the light absorbency A calculated | required from the following is 0.5 or less from the point which acquires the ultraviolet-ray absorptivity higher than the said ultraviolet absorber.
Absorbance A: absorbance measured at a wavelength of 400 nm against a 0.08% toluene solution of the ultraviolet absorber

  When the pressure-sensitive adhesive layer contains an ultraviolet light absorber, the content of the ultraviolet light absorber in the pressure-sensitive adhesive layer (particularly, acrylic pressure-sensitive adhesive layer) is not particularly limited, but the transmittance of light with a wavelength of 350 nm is controlled. The amount is preferably 0.01 parts by weight or more, more preferably 0.05 parts by weight or more, and still more preferably 0.1 parts by weight or more with respect to 100 parts by weight of the base polymer in order to obtain high UV absorption. It is at least parts by weight. Further, the upper limit of the content of the ultraviolet absorber is to suppress the occurrence of the yellowing phenomenon of the pressure-sensitive adhesive accompanying the addition of the ultraviolet absorber, and to obtain excellent optical characteristics, high transparency, and excellent appearance characteristics. More preferably, it is 10 parts by weight or less, more preferably 9 parts by weight or less, and still more preferably 8 parts by weight or less with respect to 100 parts by weight of the base polymer.

  The pressure-sensitive adhesive layer may contain a light stabilizer. When the pressure-sensitive adhesive layer contains a light stabilizer, it is particularly preferable to contain a light stabilizer together with the above-mentioned ultraviolet light absorber. Since the light stabilizer can capture radicals generated by photooxidation, the resistance of the pressure-sensitive adhesive layer to light (especially ultraviolet light) can be improved. In addition, an optical stabilizer can be used individually or in combination of 2 or more types.

  The light stabilizer is not particularly limited, and examples thereof include: phenol light stabilizers (phenolic compounds), phosphorus light stabilizers (phosphorus compounds), thioether light stabilizers (thioether compounds), amine light Stabilizers (amine compounds) (in particular, hindered amine stabilizers (hindered amine compounds)) and the like can be mentioned.

  Examples of the above-mentioned phenolic light stabilizers (phenolic compounds) include 2,6-di-tert-butyl-4-methylphenol, 4-hydroxymethyl-2,6-di-tert-butylphenol, 6-di-tert-butyl-4-ethylphenol, butylated hydroxyanisole, n-octadecyl 3- (4-hydroxy-3,5-di-tert-butylphenyl) propionate, distearyl (4-hydroxy-) 3-Methyl-5-tert-butyl) benzylmalonate, tocopherol, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-seven) Tertiary butylphenol), 4,4'-methylenebis (2,6-di-tert-butylphenol), 4,4'-butylidenebis (6-tert-butyl) m-cresol), 4,4′-thiobis (6-tertiary butyl-m-cresol), styrenated phenol, N, N′-hexamethylene bis (3,5-di-tert-butyl-4-4 Hydroxyhydrocinnamide, bis (3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid ethyl ester) calcium, 1,1,3-tris (2-methyl-4-hydroxy-5-tertiary Butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis [3- (3,5-di-) Tertiary butyl-4-hydroxyphenyl) propionyloxymethyl] methane, 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate ], 2,2'-methylenebis (4-methyl-6-cyclohexylphenol), 2,2'-methylenebis [6- (1-methylcyclohexyl) -p-cresol], 1,3,5-tris (4- Tertiary butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanuric acid, triethylene glycol- Bis [3- (3-tertiary butyl-4-hydroxy-5-methylphenyl) propionate], 2,2′-oxamidobis [ethyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate], 6- (4-hydroxy-3,5-di-tert-butylanilino) -2,4-dioctylthio-1,3,5-triazine, bis [2-tertiary Tyl-4-methyl-6- (2-hydroxy-3-tert-butyl-5-methylbenzyl) phenyl] terephthalate, 3,9-bis {2- [3- (3-tert-butyl-4-4 Hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5.5] undecane, 3,9-bis {2- [3- (3) 5-di-tertiary butyl-4-hydroxyphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5.5] undecane and the like.

  Examples of phosphorus-based light stabilizers (phosphorus-based compounds) include trisnonylphenyl phosphite, tris (2,4-di-tert-butylphenyl) phosphite, tris [2-tert-butyl-4- ( 3-tert-butyl-4-hydroxy-5-methylphenylthio) -5-methylphenyl] phosphite, tridecyl phosphite, octyl diphenyl phosphite, di (decyl) monophenyl phosphite, di (tridecyl) penta Erythritol diphosphite, distearyl pentaerythritol diphosphite, di (nonylphenyl) pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis (2,6- Di-tert-butyl-4-methylphenyl) pentaerythritol dipho Phyto, bis (2,4,6-tri-tertiary butylphenyl) pentaerythritol diphosphite, tetra (tridecyl) isopropylidene diphenol diphosphite, tetra (tridecyl) -4,4'-n-butylidene bis ( 2-tert-butyl-5-methylphenol) diphosphite, hexa (tridecyl) -1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane triphosphite, tetrakis (2) 2,4-di-tert-butylphenyl) biphenylene diphosphonite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, tris (2-[(2,4,8,7 10-Tetrakis-tert-butyldibenzo [d, f] [1,3,2] dioxaphosphepin-6-yl) o. Shi] ethyl) such as amines.

  Examples of thioether-based light stabilizers (thioether compounds) include dialkylthiodipropionate compounds such as dilauryl thiodipropionate, dimyristyl and distearyl; β of polyols such as tetrakis [methylene (3-dodecylthio) propionate] methane -Alkyl mercapto propionate ester compound etc. are mentioned.

  As an amine light stabilizer (amine light stabilizer), for example, a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidine ethanol (trade name "TINUVIN 622" (Manufactured by BASF AG), a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol and N, N ', N' ', N' ''-tetrakis- ( 4,6-Bis- (butyl- (N-methyl-2,2,6,6-tetramethylpiperidin-4-yl) amino) -triazin-2-yl) -4,7-diazadecane-1,10- One-to-one reaction product with diamine (trade name “TINUVIN 119”, manufactured by BASF AG), dibutylamine • 1,3-triazine • N, N′-bis (2,2,6,6-tetramethyl- Polycondensate of 4-piperidyl-1,6-hexamethylenediamine and N- (2,2,6,6-tetramethyl-4-piperidyl) butylamine (trade name "TINUVIN 2020", manufactured by BASF), poly [ {6- (1,1,3,3-Tetramethylbutyl) amino-1,3,5-triazine-2-4-diyl} {2,2,6,6-tetramethyl-4-piperidyl} imino] Hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}) (trade name “TINUVIN 944”, manufactured by BASF Corp.), bis (1,2,2,6,6-pentamethyl-4) -Piperidyl) a mixture of sebacate and methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate (trade name “TINUVIN 765”, manufactured by BASF), bis (2,2,6) 6-Tetramethyl-4-piperidyl) sebacate (trade name "TINUVIN 770", manufactured by BASF Corp.), bis (2,2,6,6-tetramethyl-1- (octyloxy) -4-piperidinyl) decanedioate Ester, reaction product of 1,1-dimethylethyl hydroperoxide and octane (trade name “TINUVIN 123”, manufactured by BASF), bis (1,2,2,6,6-pentamethyl-4-piperidyl) [[3 5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butyl malonate (trade name "TINUVIN 144", manufactured by BASF), cyclohexane and N-butyl 2,2,6,6 peroxide Reaction product of 2-tetramethyl-4-piperidinamine-2,4,6-trichloro-1,3,5-triazine and 2-amino acid Reaction product with methanol (trade name "TINUVIN 152", manufactured by BASF), bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and methyl 1,2,2,6,6- Mixture of pentamethyl-4-piperidyl sebacate (trade name “TINUVIN 292”, manufactured by BASF), 1,2,3,4-butanetetracarboxylic acid and 1,2,2,6,6-pentamethyl-4-piperidinol And mixed esters with 3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane (trade name "Adecastab LA-63P" And manufactured by ADEKA Co., Ltd.). Especially as a amine stabilizer, a hindered amine stabilizer is preferable.

  When the pressure-sensitive adhesive layer contains a light stabilizer, the content of the light stabilizer in the pressure-sensitive adhesive layer (particularly, acrylic pressure-sensitive adhesive layer) is not particularly limited, but the resistance to light is easily expressed. From the point of view, it is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, per 100 parts by weight of the base polymer. Further, the upper limit of the content is 5 parts by weight or less based on 100 parts by weight of the base polymer from the viewpoint that the coloring due to the light stabilizer itself hardly occurs and high transparency is easily obtained and the optical characteristics. Is preferable, and more preferably 3 parts by weight or less.

  Although it does not specifically limit for formation of the said adhesive layer, A crosslinking agent may be used. For example, the acrylic polymer in the acrylic pressure-sensitive adhesive layer can be crosslinked to control the gel fraction. In addition, a crosslinking agent can be used individually or in combination of 2 or more types.

  The crosslinking agent is not particularly limited. For example, an isocyanate crosslinking agent, an epoxy crosslinking agent, a melamine crosslinking agent, a peroxide crosslinking agent, a urea crosslinking agent, a metal alkoxide crosslinking agent, and a metal chelate crosslinking Agents, metal salt type crosslinking agents, carbodiimide type crosslinking agents, oxazoline type crosslinking agents, aziridine type crosslinking agents, amine type crosslinking agents and the like. Among them, an isocyanate crosslinking agent and an epoxy crosslinking agent are preferable, and an isocyanate crosslinking agent is more preferable.

  As said isocyanate type crosslinking agent (polyfunctional isocyanate compound), for example, lower aliphatic polyisocyanates such as 1,2-ethylene diisocyanate, 1,4-butylene diisocyanate, 1,6-hexamethylene diisocyanate; cyclopentylene diisocyanate And alicyclic polyisocyanates such as cyclohexylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate; 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate And aromatic polyisocyanates such as xylylene diisocyanate. Moreover, as said isocyanate type crosslinking agent, for example, trimethylolpropane / tolylene diisocyanate adduct (trade name "Corronate L", manufactured by Nippon Polyurethane Industry Co., Ltd.), trimethylolpropane / hexamethylene diisocyanate adduct (trade name " Commercially available products such as Coronate HL ", manufactured by Nippon Polyurethane Industry Co., Ltd., trimethylolpropane / xylylene diisocyanate adduct (trade name" Takenate D-110N "manufactured by Mitsui Chemicals, Inc.) and the like.

  Examples of the epoxy-based crosslinking agent (polyfunctional epoxy compound) include N, N, N ', N'-tetraglycidyl-m-xylenediamine, diglycidyl aniline, and 1,3-bis (N, N-diglycidyl). Aminomethyl) cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether , Glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trime Roll propane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl tris (2-hydroxyethyl) isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether And epoxy resins having two or more epoxy groups. Moreover, as said epoxy-type crosslinking agent, commercial items, such as brand name "Tetrad C" (made by Mitsubishi Gas Chemical Co., Ltd.), are also mentioned, for example.

  When a crosslinking agent is used to form the pressure-sensitive adhesive layer, the amount of the crosslinking agent used is not particularly limited, but from the viewpoint of obtaining sufficient adhesion reliability to a plastic material, based on 100 parts by weight of the base polymer The amount is preferably 0.001 parts by weight or more, more preferably 0.01 parts by weight or more. The upper limit of the amount used is preferably 10 parts by weight or less with respect to 100 parts by weight of the base polymer from the viewpoint of obtaining appropriate flexibility in the pressure-sensitive adhesive layer and improving the adhesive strength, and more preferable Is 5 parts by weight or less.

  The pressure-sensitive adhesive layer (in particular, an acrylic pressure-sensitive adhesive layer) may contain a silane coupling agent. In addition, a silane coupling agent can be used individually or in combination of 2 or more types. When the pressure-sensitive adhesive layer contains a silane coupling agent, adhesion under humidified conditions, in particular adhesion to glass, can be improved.

  The above-mentioned silane coupling agent is not particularly limited. For example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-aminopropyltri Methoxysilane etc. are mentioned. Furthermore, as a silane coupling agent, commercial products, such as brand name "KBM-403" (made by Shin-Etsu Chemical Co., Ltd.), are mentioned, for example. Among them, γ-glycidoxypropyltrimethoxysilane is preferable as the above-mentioned silane coupling agent.

  When the pressure-sensitive adhesive layer contains a silane coupling agent, the content of the silane coupling agent in the pressure-sensitive adhesive layer (particularly, acrylic pressure-sensitive adhesive layer) is not particularly limited. It is preferable that it is 0.01 weight part or more with respect to a part, More preferably, it is 0.02 weight part or more. The upper limit of the content of the silane coupling agent is preferably 1 part by weight or less, more preferably 0.5 parts by weight or less, with respect to 100 parts by weight of the base polymer.

  The pressure-sensitive adhesive layer may further contain, if necessary, a crosslinking accelerator, a tackifying resin (a rosin derivative, a polyterpene resin, a petroleum resin, an oil-soluble phenol, etc.), an antioxidant, a filler, a coloring agent (pigment, dye, etc.) ), Additives such as an antioxidant, a chain transfer agent, a plasticizer, a softener, a surfactant, an antistatic agent, etc. may be contained in the range which does not impair the effect of the present invention. In addition, such an additive can be used individually or in combination of 2 or more types.

The elastic modulus at 95 ° C. of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 4.0 × 10 ⁴ Pa or more, more preferably 5.0 × 10 ⁴ Pa or more, still more preferably 6.0 × 10 ⁴ Pa It is above. The vehicle interior in which the optical product having the double-sided pressure-sensitive adhesive sheet for optical of the present invention is installed at a high temperature environment as the above elastic modulus is 4.0 × 10 ⁴ Pa or more (particularly, 5.0 × 10 ⁴ Pa or more) Even in the case where it is not preferred, bubbles are less likely to be generated in the pressure-sensitive adhesive layer and the adhesion reliability to the plastic material is excellent. The upper limit of the elastic modulus at 95 ° C. is not particularly limited, but is preferably 1.0 × 10 ⁶ Pa or less, more preferably 5.0 × 10 ⁵ Pa or less, still more preferably 1.0 × 10 ⁵ Pa or less is there. When the optical double-sided pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet with a substrate, at least one pressure-sensitive adhesive layer may be a pressure-sensitive adhesive layer having an elastic modulus of 95 ° C. within the above range. In particular, from the viewpoint of excellent adhesion reliability to a plastic material, it is preferable that at least the pressure-sensitive adhesive layer to be attached to the optical member which is a plastic material be a pressure-sensitive adhesive layer having an elastic modulus of 95 ° C. within the above range. .

  The measurement of the elastic modulus at 95 ° C. is obtained as follows. From the pressure-sensitive adhesive layer (thickness: about 2 mm), this is punched out to φ 7.9 mm, and a cylindrical pellet is produced to be a measurement sample. The measurement sample is fixed to a jig of 7.97.9 mm parallel plate, and the temperature dependency of the storage elastic modulus G 'is measured by a dynamic viscoelasticity measuring device (ARES manufactured by Rheometrics Co., Ltd.). That is, storage elastic modulus (G ') at 95 ° C. when measured in the measurement: shear mode, temperature range: −70 ° C. to 150 ° C., temperature rising rate: 5 ° C./min, frequency: 1 Hz.

The elastic modulus at 25 ° C. of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 1.0 × 10 ⁶ Pa or less, more preferably 5.0 × 10 ⁵ Pa or less, still more preferably 2.0 × 10 ⁵ Pa It is below. If the elastic modulus is 1.0 × 10 ⁶ Pa or less, the adhesion to the optical member, which is the adherend of the optical double-sided pressure-sensitive adhesive sheet of the present invention, and the step following to the optical member tend to be improved. preferable. The lower limit of the elastic modulus at 25 ° C. is not particularly limited, but is preferably 1.0 × 10 ⁴ Pa or more, more preferably 5.0 × 10 ⁴ Pa or more, still more preferably 1.0 × 10 ⁵ Pa or more is there. When the optical double-sided pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet with a substrate, at least one pressure-sensitive adhesive layer may be a pressure-sensitive adhesive layer having an elastic modulus of 25 ° C. within the above range.

  The measurement of the elastic modulus at 25 ° C. is obtained as follows. From the pressure-sensitive adhesive layer (thickness: about 2 mm), this is punched out to φ 7.9 mm, and a cylindrical pellet is produced to be a measurement sample. The measurement sample is fixed to a jig of 7.97.9 mm parallel plate, and the temperature dependency of the storage elastic modulus G 'is measured by a dynamic viscoelasticity measuring device (ARES manufactured by Rheometrics Co., Ltd.). That is, storage elastic modulus (G ') at 25 ° C. when measured in the measurement: shear mode, temperature range: −70 ° C. to 150 ° C., temperature rising rate: 5 ° C./min, frequency: 1 Hz.

  The haze of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 5% or less, more preferably 3% or less, and still more preferably 1% or less from the viewpoint of appearance characteristics, transparency and visibility of the optical product. is there. In the present specification, the haze can be measured, for example, using a haze meter in accordance with JIS K 7136.

  The total light transmittance of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 85% or more, more preferably 90% or more, and still more preferably 92 from the viewpoint of appearance characteristics, transparency and visibility of the optical product. % Or more. In the present specification, the total light transmittance can be measured according to JIS K 7361-1 using, for example, a haze meter. The total light transmittance is a transmittance of light (visible light) having a wavelength of 400 to 780 nm.

The a ^{* of the} pressure-sensitive adhesive layer is not particularly limited, but is preferably −0.5 or more, more preferably −0.3 or more from the viewpoint of obtaining excellent optical characteristics and excellent appearance characteristics. More preferably, it is -0.1 or more. Moreover, it is preferable that it is 0.5 or less from the point which obtains the outstanding optical characteristic and the outstanding appearance characteristic, More preferably, it is 0.3 or less, More preferably, it is 0.1 or less. In this specification, a ^* value, L ^* a ^* b ^* is a ^* values of the color system, conforming to JIS Z 8781-4 (2013 years), for example, simplified Spectrophotometer (product It can be measured by the name "DOT-3C" (manufactured by Murakami Color Research Laboratory).

The b ^{* of the} pressure-sensitive adhesive layer is not particularly limited, but is preferably 1.0 or less, more preferably 0.8 or less, and still more preferably 0.6 or less. When b ^* is 1.0 or less, the optical characteristics are excellent and the appearance characteristics are excellent. An optical product (particularly, an optical product having a display panel such as LCD) using the optical double-sided pressure-sensitive adhesive sheet of the present invention has the advantage of not impairing the brightness, color density and color tone of the screen . In the present specification, b ^* values, L ^* a ^* b ^* a b ^* value of the color system, conforming to JIS Z 8781-4 (2013 years), for example, simplified Spectrophotometer (product It can be measured by the name "DOT-3C" (manufactured by Murakami Color Research Laboratory).

  When the optical double-sided pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet with a substrate, the thickness of the pressure-sensitive adhesive layer (the thickness of one pressure-sensitive adhesive layer) is not particularly limited, but is preferably 100 to 2925 μm, more preferably 200 It is -2000 micrometers, More preferably, it is 300-1000 micrometers. When the thickness is 100 μm or more, the optical double-sided pressure-sensitive adhesive sheet of the present invention has better adhesion when used in an on-vehicle optical product. The two pressure-sensitive adhesive layers provided on both sides of the substrate may have the same thickness or may have different thicknesses.

  The method for producing the pressure-sensitive adhesive layer (in particular, an acrylic pressure-sensitive adhesive layer) is not particularly limited. For example, the pressure-sensitive adhesive obtained by applying (coating) the above-mentioned pressure-sensitive adhesive composition on a substrate or a release liner Drying and curing the composition layer or applying (applying) the above-mentioned pressure-sensitive adhesive composition onto a substrate or release liner, and irradiating the resulting pressure-sensitive adhesive composition layer with active energy rays to cure the composition. It can be mentioned. Moreover, you may heat-dry further as needed.

  Examples of the active energy ray include ionizing radiation such as alpha rays, beta rays, gamma rays, neutron rays, and electron rays, and ultraviolet rays. Particularly, ultraviolet rays are preferable. Further, the irradiation energy of the active energy ray, the irradiation time, the irradiation method and the like are not particularly limited.

  The above-mentioned pressure-sensitive adhesive composition can be prepared by a known or conventional method. For example, a solvent-type acrylic pressure-sensitive adhesive composition can be produced by mixing an additive with a solution containing the above-mentioned acrylic polymer, as required. For example, an active energy ray-curable acrylic pressure-sensitive adhesive composition can be prepared by mixing an additive with the mixture of acrylic monomers or a partial polymer thereof, as necessary.

  In addition, you may utilize the well-known coating method for application | coating (coating) of the said adhesive composition. For example, coaters such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, a spray coater, a comma coater, and a direct coater may be used.

  In particular, when the pressure-sensitive adhesive layer is formed of an active energy ray-curable pressure-sensitive adhesive composition, the active energy ray-curable pressure-sensitive adhesive composition preferably contains a photopolymerization initiator. When the active energy ray-curable pressure-sensitive adhesive composition contains an ultraviolet absorber, it is preferable to include at least a photopolymerization initiator having light absorption characteristics in a wide wavelength range as the photopolymerization initiator. For example, in addition to ultraviolet light, it is preferable to include at least a photopolymerization initiator having absorption characteristics even in visible light. This is because there is a concern about the inhibition of curing by active energy rays due to the action of the ultraviolet absorber, and when the photopolymerization initiator having the light absorption characteristics in a wide wavelength range is included, the high photocurability in the pressure-sensitive adhesive composition It is because it becomes easy to obtain.

  When the optical double-sided pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet with a substrate, it is not particularly limited, but at least one pressure-sensitive adhesive layer is the pressure-sensitive adhesive layer exemplified and described as a preferred embodiment of the pressure-sensitive adhesive layer. Is preferred. When the optical double-sided pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet with a substrate, the two pressure-sensitive adhesive layers provided on both sides of the substrate may be pressure-sensitive adhesive layers of the same composition or different. It may be an adhesive layer of a composition. As the pressure-sensitive adhesive layer having a different composition, for example, when the types and amounts of raw material monomers constituting the base polymer contained in the pressure-sensitive adhesive layer are different, the base polymer contained in the pressure-sensitive adhesive layer is the same but the base polymer And cases where the content of additives differs. Among them, the two pressure-sensitive adhesive layers are preferably pressure-sensitive adhesive layers of the same composition (that is, pressure-sensitive adhesive layers formed from the same pressure-sensitive adhesive composition).

(Base material)
The substrate in the case where the double-sided pressure-sensitive adhesive sheet for optics of the present invention is a pressure-sensitive adhesive sheet with a substrate is not particularly limited, but for example, various optical films such as plastic films, antireflection (AR) films, polarizing plates, retardation plates, etc. A film is mentioned. Examples of materials for the plastic film and the like include polyester resins such as polyethylene terephthalate (PET), acrylic resins such as polymethyl methacrylate (PMMA), polycarbonate, triacetyl cellulose (TAC), polysulfone, polyarylate, polyimide, Polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, ethylene-propylene copolymer, trade name "Arton" (cyclic olefin polymer, manufactured by JSR Corporation), trade name "Zeonor" (cyclic olefin polymer, Nippon Zeon And plastic materials such as cyclic olefin-based polymers, etc. In addition, these plastic materials can be used individually or in combination of 2 or more types. Moreover, said "base material" is a part affixed on a to-be-adhered body with an adhesive layer, when sticking a pressure-sensitive adhesive sheet to a to-be-adhered body (optical member etc.). Release liners that are released when the adhesive sheet is used (during application) are not included in the "substrate".

  The in-plane retardation Re of the substrate is not particularly limited, but is preferably 20 nm or less, more preferably 10 nm or less, still more preferably 1 nm or less, and particularly preferably 0.5 nm or less. When the in-plane retardation is 20 nm or less, rainbow unevenness (coloring due to birefringence) caused by the substrate is less likely to occur, which is preferable because the visibility of the optical product can be further improved. In the present specification, the in-plane retardation refers to the in-plane retardation value of the substrate at a wavelength of 590 nm at 23 ° C. In Re, the refractive index in the direction in which the in-plane refractive index is maximum (namely, the slow axis direction) is nx, and the refractive index in the direction orthogonal to the slow axis in the plane (namely, the fast axis direction) It is calculated | required by Re = (nx-ny) xd, when it is ny and thickness of a base material is d (nm).

  The in-plane retardation (Re) of the base material may be extremely large. In this case, the in-plane retardation of the substrate is not particularly limited, but is preferably 4000 nm or more, more preferably 6000 nm or more, still more preferably 8000 nm or more, and particularly preferably 10000 nm or more. If the in-plane retardation is 4000 nm or more, rainbow unevenness is less likely to occur and the visibility of the optical product can be further improved, even if the thickness of the substrate is large, which is preferable. The upper limit of the in-plane retardation is not particularly limited, but is preferably 20000 nm or less, more preferably 15000 nm or less, and still more preferably 13000 nm or less.

  The substrate is preferably transparent. The total light transmittance (in accordance with JIS K 7361-1) in the visible light wavelength region of the base is not particularly limited, but is preferably 85% or more, and more preferably 88% or more. Moreover, the haze (according to JIS K 7136) of the above-mentioned base material is not particularly limited, but is preferably 1.5% or less, more preferably 1.0% or less.

  Although the thickness of the said base material is not specifically limited, 75-500 micrometers is preferable, More preferably, it is 80-300 micrometers, More preferably, it is 100-200 micrometers. When the thickness of the substrate is 75 μm or more, the optical double-sided pressure-sensitive adhesive sheet of the present invention has better adhesion when used in an on-vehicle optical product.

  The substrate may have any form of single layer and multiple layers. In addition, the surface of the substrate may be appropriately subjected to known and commonly used surface treatments such as physical treatments such as corona discharge treatment and plasma treatment, and chemical treatments such as undercoating treatment.

(Peeling liner)
In the optical double-sided pressure-sensitive adhesive sheet of the present invention, a release liner (separator) may be provided on the surface (pressure-sensitive adhesive surface) of the pressure-sensitive adhesive layer until use. The pressure-sensitive adhesive surfaces of the optical double-sided pressure-sensitive adhesive sheet of the present invention may be each protected by two release liners, or may be wound into a roll by one release liner having release surfaces on both sides. It may be protected in the form (rolled body). The release liner is used as a protective material for the pressure-sensitive adhesive layer, and is peeled off when applied to an adherend. Moreover, when the double-sided pressure-sensitive adhesive sheet for optics of the present invention is a substrate-less pressure-sensitive adhesive sheet, the release liner also plays a role as a support for the pressure-sensitive adhesive layer. The release liner may not necessarily be provided.

  A conventional release paper can be used as the release liner, and is not particularly limited. For example, a base having a release treatment layer, a low adhesive base comprising a fluorine polymer, or a low adhesive base comprising a nonpolar polymer Etc. As a base material which has the said peeling process layer, the plastic film and paper etc. which were surface-treated by peeling process agents, such as a silicone type, a long chain alkyl type, a fluorine type, and a molybdenum sulfide, are mentioned, for example. Examples of the fluorine-based polymer in the low adhesive base material composed of the above-mentioned fluorine-containing polymer include polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, chloro Fluoroethylene-vinylidene fluoride copolymer etc. are mentioned. Moreover, as said nonpolar polymer, olefin resin (for example, polyethylene, a polypropylene etc.) etc. are mentioned, for example. The release liner can be formed by a known or conventional method.

  When the release liner has a release-treated layer, the thickness (thickness of one layer) of the release liner is not particularly limited, but is preferably 75 to 250 μm, more preferably 100 to 200 μm, and still more preferably 100 to 150 μm. When the thickness is 75 μm or more, in the case where the optical double-sided pressure-sensitive adhesive sheet having a thickness of 500 μm or more is used as a wound body, wrinkles may not easily enter the release treatment layer, which is preferable.

(Optical double-sided pressure-sensitive adhesive sheet of the present invention)
The haze of the optical double-sided pressure-sensitive adhesive sheet of the present invention is not particularly limited, but is preferably 5% or less, more preferably 3% or less, from the viewpoint of the appearance characteristics of the optical product, transparency, and visibility. It is at most 1.5%, particularly preferably at most 1%.

  The total light transmittance of the optical double-sided pressure-sensitive adhesive sheet of the present invention is not particularly limited, but is preferably 85% or more, more preferably 90% or more, from the viewpoint of appearance characteristics, transparency and visibility of optical products. More preferably, it is 92% or more.

The a ^* of the optical double-sided pressure-sensitive adhesive sheet of the present invention is not particularly limited, but is preferably -0.5 or more, more preferably -0.3 in order to obtain excellent optical characteristics and excellent appearance characteristics. Or more, more preferably -0.1 or more. Moreover, it is preferable that it is 0.5 or less from the point which obtains the outstanding optical characteristic and the outstanding appearance characteristic, More preferably, it is 0.3 or less, More preferably, it is 0.1 or less.

The b ^* of the optical double-sided pressure-sensitive adhesive sheet of the present invention is not particularly limited, but is preferably 1.5 or less, more preferably 1.1 or less, still more preferably 0.7 or less, particularly preferably 0 .4 or less. When b ^* is 1.5 or less, the optical properties are excellent and the appearance properties are excellent. An optical product (particularly, an optical product having a display panel such as LCD) using the optical double-sided pressure-sensitive adhesive sheet of the present invention has the advantage of not impairing the brightness, color density and color tone of the screen .

  The adhesive force of the optical double-sided pressure-sensitive adhesive sheet of the present invention is not particularly limited, but is preferably 6 N / 20 mm or more, more preferably 7 N / 20 mm or more, further preferably from the viewpoint of adhesion to the optical member. It is 10 N / 20 mm or more. The adhesive strength is 180 ° peeling adhesive strength, and in accordance with JIS Z 0237, it is measured by peeling off from the adherend under conditions of a tensile speed of 300 mm / min and a tensile angle of 180 ° (degree). Can. The adhesive strength of at least one adhesive surface of the optical double-sided pressure-sensitive adhesive sheet of the present invention may be within the above range, but the adhesive strength of both adhesive surfaces is preferably within the above range.

  The optical double-sided pressure-sensitive adhesive sheet of the present invention has a thickness of 500 μm or more. For this reason, when it uses for a vehicle-mounted optical product, the bonding property of an optical member becomes favorable.

  The optical double-sided pressure-sensitive adhesive sheet of the present invention is not particularly limited, but is preferably produced according to a known or conventional production method. For example, when the optical double-sided pressure-sensitive adhesive sheet of the present invention is a substrateless pressure-sensitive adhesive sheet, it can be obtained by forming the above-mentioned pressure-sensitive adhesive layer on the release liner by the above method. Moreover, when the double-sided pressure-sensitive adhesive sheet for optics of the present invention is a pressure-sensitive adhesive sheet with a substrate, it may be obtained by directly forming the above-mentioned pressure-sensitive adhesive layer on the surface of the substrate (direct printing method) After the pressure-sensitive adhesive layer is formed thereon, the pressure-sensitive adhesive layer may be obtained by providing the pressure-sensitive adhesive layer on the substrate by transferring (bonding) to the substrate (transfer method). Among them, since the optical double-sided sheet of the present invention has a thickness of 500 μm or more, the transfer method is preferable from the viewpoint of easily forming a sufficiently cured pressure-sensitive adhesive layer.

  The optical double-sided pressure-sensitive adhesive sheet of the present invention is used in an on-vehicle optical product. Specifically, it is used for the application (optical member bonding application) which bonds together the optical member used for a vehicle-mounted optical product.

  The above optical member is a member having optical properties (eg, polarization, light refraction, light scattering, light reflectivity, light transmission, light absorption, light diffraction, optical rotation, visibility, etc.) Say. The substrate constituting the optical member is not particularly limited, and examples thereof include substrates constituting devices (optical devices) such as display devices (image display devices) and input devices, and substrates used for these devices, For example, at least one surface of a polarizing plate, a wavelength plate, a retardation plate, an optical compensation film, a brightness enhancement film, a light guide plate, a reflection film, an antireflection film, a hard coat film (a plastic film such as a PET film is subjected to hard coating treatment Film, transparent conductive film, design film, decorative film, surface protection plate (plastic cover), prism, lens, color filter, transparent substrate (glass sensor, glass display panel, liquid crystal display panel (LCD), with transparent electrode) Glass substrate such as glass plate (in-cell, on-cell etc.), bezel (frame) News substrate to which they are stacked (these are generically sometimes referred to as "functional film"), and the like. Moreover, these films may have a printing layer, a metal nanowire layer, a conductive polymer layer, and the like. Moreover, fine metal wires may be mesh-printed on these films. In addition, said "plate" and "film" shall include forms, such as plate shape, film shape, sheet shape, respectively, For example, a "polarizing film" shall contain a "polarizing plate", a "polarizing sheet", etc. .

  Examples of the optical member include a touch sensor and a film sensor. More specifically, a film having an ITO (indium tin oxide) layer on the surface; a film having a zinc oxide (ZnO) layer on the surface; a film obtained by applying a liquid containing metal nanoparticles on the surface, metal nano A film using metal nanoparticles such as a film obtained by mesh printing the surface with a liquid containing particles; a film obtained by applying a dispersion containing carbon nanotubes on the surface, a surface containing a liquid containing carbon nanotubes A film using carbon nanotubes such as a film obtained by mesh printing: a film using graphene such as a film having a graphene layer on the surface; a film having a conductive polymer layer on the surface, a conductive polymer Such as a film obtained by mesh printing with a liquid containing Transparent conductive film such as a film with sexual polymer. In addition, a film using a metal (in particular, copper) such as a film having a mesh-like fine metal wire pattern or a film having a metal layer can be mentioned. Furthermore, a silver nanowire film is mentioned.

  Examples of the display device include a liquid crystal display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), an electronic paper, and the like. Moreover, a touch panel etc. are mentioned as said input device.

  The optical double-sided pressure-sensitive adhesive sheet of the present invention is particularly preferably a full-lamination pressure-sensitive adhesive sheet used to fill an air gap in an on-vehicle optical product. When the double-sided pressure-sensitive adhesive sheet for optical use of the present invention is used for full lamination of an in-vehicle optical product, loss of light quantity due to light reflection and diffusion in the optical product can be reduced, and the visibility of the optical product is increased. It can be improved.

  The on-vehicle optical product includes at least the optical double-sided pressure-sensitive adhesive sheet of the present invention. Examples of the above-mentioned in-vehicle optical products include products having the above-mentioned optical members, and examples thereof include car navigation systems, DVD players, Blu-ray disc players, music players, liquid crystal televisions, organic ELs, various meter display sections and the like. .

  Examples of a car in which the above-mentioned in-vehicle optical product is used include a car, a bicycle, a motorcycle (including a motor bike), a train, a locomotive, etc. Among them, a car is preferable.

  More specifically, the aspect by which the double-sided pressure-sensitive adhesive sheet for optics of the present invention is used for an optical product for vehicles will be described. 1 and 2 are each a schematic cross-sectional view showing an example of an on-vehicle optical product in which the optical double-sided pressure-sensitive adhesive sheet of the present invention is used. Specifically, in each of FIGS. 1 and 2, the double-sided pressure-sensitive adhesive sheet for optics of the present invention is used for full lamination. The mode in which the optical double-sided pressure-sensitive adhesive sheet of the present invention is used in an on-vehicle optical product is not limited to the modes shown in FIGS. 1 and 2.

  In the in-vehicle optical product 1 of FIG. 1, the glass sensor 5; the polarizing plate 9a; the bezel 9 for protecting the polarizing plate 9a, the liquid crystal display 10, and the polarizing plate 9b; The optical double-sided pressure-sensitive adhesive sheet 8 of the present invention is used in such a manner that the polarizer 5 and the polarizing plate 9a are pasted together. In addition, although the area | region where the double-sided adhesive sheet 8 for optics of this invention is used is an air gap conventionally in the optical product for vehicles, this air gap is an optical double-sided adhesive sheet 8 of this invention By filling, the in-vehicle optical product 1 has become an in-vehicle optical product in which the full lamination technology is adopted. In addition, in FIG. 1, although the adhesive sheet 4 can use a well-known thru | or common double-sided adhesive sheet for optics, you may use the double-sided adhesive sheet for optics of this invention.

  The on-vehicle optical product 1 of FIG. 2 is an example of an on-cell type or in-cell type optical product. In the in-vehicle optical product 1 of FIG. 2, the plastic cover 2; the printing layer 3; the polarizing plate 9a; the bezel 7 for protecting the polarizing plate 9a, the on cell or in cell 11, and the polarizing plate 9b; The optical double-sided pressure-sensitive adhesive sheet 8 of the present invention is used in such a manner that the plastic cover 2 and the polarizing plate 9a are bonded to each other in the region. In addition, although the area | region where the double-sided adhesive sheet 8 for optics of this invention is used is an air gap conventionally in the optical product for vehicles, this air gap is an optical double-sided adhesive sheet 8 of this invention By filling, the in-vehicle optical product 1 has become an in-vehicle optical product in which the full lamination technology is adopted.

  1 and 2 show an example of an on-vehicle optical product having a bezel (on-vehicle optical product with a bezel), but the optical double-sided pressure-sensitive adhesive sheet of the present invention is an on-vehicle optical device having no bezel. It may be used for products (bezelless automotive optical products), in particular for full lamination.

  EXAMPLES The present invention will be described in more detail based on examples given below, but the present invention is not limited by these examples. In addition, the number of compounding parts (parts by weight) is a value in terms of solid content (nonvolatile content).

(Preparation Example 1 of Acrylic Polymer)
60 parts by weight of dicyclopentanyl methacrylate (DCPMA, dicyclopentanyl methacrylate), 40 parts by weight of methyl methacrylate (MMA, methyl methacrylate), 3.5 parts by weight of α-thioglycerol as a chain transfer agent And 100 parts by weight of toluene as a polymerization solvent were charged into a four-necked flask, and these were stirred at 70 ° C. for 1 hour under a nitrogen atmosphere. Next, 0.2 parts by weight of 2,2′-azobisisobutyro nitrile as a polymerization initiator is charged into a four-necked flask, and reacted at 70 ° C. for 2 hours, followed by 2 hours at 80 ° C. It was made to react. Thereafter, the reaction solution is charged under a temperature atmosphere of 130 ° C., toluene, a chain transfer agent, and unreacted monomers are removed by drying, and solid acrylic polymer ("acrylic polymer (A) may be referred to as") Got). The weight average molecular weight of the acrylic polymer (A) was 5.1 × 10 ³ .

Example 1
A monomer mixture composed of 67 parts by weight of 2-ethylhexyl acrylate (2EHA), 15 parts by weight of N-vinyl-2-pyrrolidone (NVP), and 18 parts by weight of 2-hydroxyethyl acrylate (HEA) After blending 0.035 parts by weight of a polymerization initiator (trade name “IRGACURE 651”, manufactured by BASF) and 0.035 parts by weight of a photopolymerization initiator (trade name “IRGACURE 184”, manufactured by BASF) The ultraviolet ray was irradiated until the viscosity (BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30 ° C.) became about 20 Pa · s, to obtain a prepolymer composition in which a part of the above-mentioned monomer component was polymerized.
5 parts by weight of the above acrylic polymer (A), 0.075 parts by weight of hexanediol acrylate (HDDA), and a silane coupling agent (trade name “KBM-403”, Shin-Etsu Chemical Co., Ltd.) Product): 0.3 parts by weight was mixed to obtain an acrylic pressure-sensitive adhesive composition.
The acrylic pressure-sensitive adhesive composition was applied onto a polyethylene terephthalate (PET) -based release liner (manufactured by Nitto Denko Corporation, thickness: 125 μm) to form a pressure-sensitive adhesive composition layer. Then, a PET-based release liner (manufactured by Nitto Denko Corporation, thickness: 125 μm) was provided on the pressure-sensitive adhesive composition layer, and the pressure-sensitive adhesive composition layer was coated to block oxygen. Then, a laminate (laminate (I)) having a configuration of [release liner / adhesive composition layer / release liner] was obtained.
Next, the laminate (I) was irradiated with ultraviolet light with an illuminance of 3 mW / cm ² for 300 seconds from the upper surface (release liner side) of the laminate (I) with a black light (manufactured by Toshiba Corporation) . Furthermore, the drying process was performed for 2 minutes with a 90 degreeC dryer, the remaining monomer was volatilized, and the laminated body (laminated body (II)) which has a structure of [release liner / adhesive layer / release liner] was obtained. The thickness of the pressure-sensitive adhesive layer was 500 μm.
The release liner on one side of the laminate (II) is peeled off, and the surface of the pressure-sensitive adhesive layer is bonded to one surface of a polyethylene terephthalate (PET) film (thickness: 125 μm, in-plane retardation Re: 4200 nm) A laminate (laminate (III)) having a configuration of [release liner / adhesive layer / PET film] was obtained.
Furthermore, the release liner on one side of the separately prepared laminate (II) is peeled off, and the surface of the pressure-sensitive adhesive layer and the surface of the PET film of the laminate (III) are bonded to each other. A double-sided pressure-sensitive adhesive sheet (a double-sided pressure-sensitive adhesive sheet with a substrate) having a configuration of PET film / pressure-sensitive adhesive layer / release liner was produced. The thickness of the double-sided pressure-sensitive adhesive sheet (thickness excluding the release liner) was 1125 μm.

(Example 2)
57 parts by weight of n-butyl acrylate (BA), 12 parts by weight of cyclohexyl acrylate (CHA), 23 parts by weight of 4-hydroxybutyl acrylate (4 HBA), 8 parts by weight of 2-hydroxyethyl acrylate (HEA) And 0.05 parts by weight of a photopolymerization initiator (trade name "IRGACURE 651", manufactured by BASF AG), and a photopolymerization initiator (trade name "IRGACURE 184", manufactured by BASF AG): After blending 0.05 parts by weight, ultraviolet light was irradiated until the viscosity (BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30 ° C.) became about 20 Pa · s, and a part of the above monomer component was polymerized. The prepolymer composition was obtained.
0.1 parts by weight of dipentaerythritol hexaacrylate (DPHA) and 0.3 parts by weight of silane coupling agent (trade name "KBM-403", manufactured by Shin-Etsu Chemical Co., Ltd.) are mixed with the above prepolymer composition. An acrylic pressure-sensitive adhesive composition was obtained.
A release liner / pressure-sensitive adhesive layer is used in the same manner as in Example 1 except that a PET film (thickness: 100 μm, in-plane retardation Re: 10000 nm) is used as the PET film using the above-mentioned acrylic pressure-sensitive adhesive composition. A double-sided pressure-sensitive adhesive sheet (a double-sided pressure-sensitive adhesive sheet with a substrate) having a structure of: / PET film / pressure-sensitive adhesive layer / release liner was produced. The thickness (thickness excluding the release liner) of the double-sided pressure-sensitive adhesive sheet was 1100 μm.

(Example 3)
Acrylic acid 2-ethylhexyl (2EHA): 40.5 parts by weight, isostearyl acrylate (ISTA): 40.5 parts by weight, N-vinyl-2-pyrrolidone (NVP): 18 parts by weight, 4-hydroxybutyl acrylate ( 4 HBA: 1 part by weight of a monomer mixture, photo polymerization initiator (trade name “IRGACURE 651”, manufactured by BASF Corp.): 0.05 parts by weight, and photo polymerization initiator (trade name “IRGA CURE 184” After blending 0.5 parts by weight of BASF Co., Ltd., ultraviolet rays are irradiated until the viscosity (BH viscometer No. 5 rotor, 10 rpm, measurement temperature 30 ° C.) becomes about 20 Pa · s, and the above-mentioned monomer component A prepolymer composition in which a part of the polymer was polymerized was obtained.
0.02 parts by weight of trimethylolpropane triacrylate (TMPTA) and 0.3 parts by weight of a silane coupling agent (trade name "KBM-403" manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed with the above prepolymer composition. The acrylic pressure-sensitive adhesive composition was obtained.
A double-sided pressure-sensitive adhesive sheet (double-sided adhesion with a substrate) having the structure of [release liner / pressure-sensitive adhesive layer / PET film / pressure-sensitive adhesive layer / release liner] in the same manner as in Example 1 using the above acrylic pressure-sensitive adhesive composition Sheet was produced. The thickness of the double-sided pressure-sensitive adhesive sheet (thickness excluding the release liner) was 1125 μm.

(Example 4)
A laminate was prepared in the same manner as the laminate (II) produced in Example 1 except that the thickness of the pressure-sensitive adhesive layer was 550 μm, and the pressure-sensitive adhesive layer was composed of only a pressure-sensitive adhesive layer. A base-less type double-sided pressure-sensitive adhesive sheet protected by The thickness of the double-sided pressure-sensitive adhesive sheet was 550 μm.

(Example 5)
A laminate is prepared in the same manner as the laminate (II) produced in Example 1 except that the thickness of the pressure-sensitive adhesive layer is set to 610 μm, and the pressure-sensitive adhesive layer is composed of only a pressure-sensitive adhesive layer. A base-less type double-sided pressure-sensitive adhesive sheet protected by The thickness of the double-sided pressure-sensitive adhesive sheet was 610 μm.

(Comparative example 1)
A laminate is produced in the same manner as the laminate (II) produced in Example 1 except that the thickness of the pressure-sensitive adhesive layer is 250 μm, and the pressure-sensitive adhesive layer is composed of only a pressure-sensitive adhesive layer. A base-less type double-sided pressure-sensitive adhesive sheet protected by The thickness of the double-sided pressure-sensitive adhesive sheet was 250 μm.

(Evaluation)
The following measurement was performed about the double-sided adhesive sheet obtained by the Example and the comparative example. The results are shown in Table 1.

(Total light transmittance)
The release liner on one side of the double-sided pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples was peeled off, and the double-sided pressure-sensitive adhesive sheet was slide glass (trade name "MICRO SLIDE GLASS", white polished, NO. 2, thickness: 1.0 to 1. It stuck on 2 mm and Matsunami-Glass Co., Ltd. product), and it was left to stand in the environment of temperature 23 degreeC, and humidity 50% RH. After standing, the other release liner was removed and used as a test piece.
When the double-sided pressure-sensitive adhesive sheet was attached, a hand roller was used to prevent dirt such as fingerprints from adhering to the surface and prevent foreign matter and air bubbles from being caught.
The total light transmittance of the test piece was measured using a haze meter (trade name “HM-150”, manufactured by Murakami Color Research Laboratory) under an environment of 23 ° C. and 50% RH.
The measurement of the total light transmittance was performed according to JIS K 7361-1.

(Haze)
The release liner on one side of the double-sided pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples was peeled off, and the double-sided pressure-sensitive adhesive sheet was slide glass (trade name "MICRO SLIDE GLASS", white polished, NO. 2, thickness: 1.0 to 1. It stuck on 2 mm and Matsunami-Glass Co., Ltd. product), and it was left to stand in the environment of temperature 23 degreeC, and humidity 50% RH. After standing, the other release liner was removed and used as a test piece.
When the double-sided pressure-sensitive adhesive sheet was attached, a hand roller was used to prevent dirt such as fingerprints from adhering to the surface and prevent foreign matter and air bubbles from being caught.
The haze of the test piece was measured using a haze meter (trade name “HM-150”, manufactured by Murakami Color Research Laboratory, Inc.) under an environment of 23 ° C. and 50% RH.
The measurement of the haze was performed according to JIS K 7136.

(B ^* (L ^* a ^* b ^* b ^* value of color system))
The release liner on one side of the double-sided pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples was peeled off, and the double-sided pressure-sensitive adhesive sheet was slide glass (trade name "MICRO SLIDE GLASS", white polished, NO. 2, thickness: 1.0 to 1. It stuck on 2 mm and Matsunami-Glass Co., Ltd. product), and it was left to stand in the environment of temperature 23 degreeC, and humidity 50% RH. After standing, the other release liner was removed and used as a test piece.
When the double-sided pressure-sensitive adhesive sheet was attached, a hand roller was used to prevent dirt such as fingerprints from adhering to the surface and prevent foreign matter and air bubbles from being caught.
The b ^* value of the test piece was measured using a simple type spectrocolorimeter (trade name "DOT-3C", manufactured by Murakami Color Research Laboratory, Inc.). The measurement was performed by applying light to the exposed adhesive surface of the test piece.
The measurement of b ^* value was performed according to JIS Z 8781-4 (2013).

(Elastic modulus of 25 ° C)
In the same manner as the pressure-sensitive adhesive layers obtained in Examples and Comparative Examples, pressure-sensitive adhesive layers are produced so as to have a thickness of about 2 mm, respectively, which are punched into φ7.9 mm to produce cylindrical pellets. It was used as a measurement sample. The above measurement sample is fixed to a jig of 7.97.9 mm parallel plate, and a dynamic viscoelasticity measurement apparatus (manufactured by Rheometrics, ARES, measurement: shear mode, temperature range: -70 ° C to 150 ° C, temperature rising rate: 5) The temperature dependency of the storage elastic modulus G ′ was measured by ° C./min, frequency: 1 Hz, and the storage elastic modulus G ′ at 25 ° C. was taken as the elastic modulus at 25 ° C.

(Elastic modulus of 95 ° C)
In the same manner as the pressure-sensitive adhesive layers obtained in Examples and Comparative Examples, pressure-sensitive adhesive layers are produced so as to have a thickness of about 2 mm, respectively, which are punched into φ7.9 mm to produce cylindrical pellets. It was used as a measurement sample. The above measurement sample is fixed to a jig of 7.97.9 mm parallel plate, and a dynamic viscoelasticity measurement apparatus (manufactured by Rheometrics, ARES, measurement: shear mode, temperature range: -70 ° C to 150 ° C, temperature rising rate: 5) The temperature dependency of the storage elastic modulus G ′ was measured by ° C./min, frequency: 1 Hz, and the storage elastic modulus G ′ at 95 ° C. was taken as the elastic modulus of 95 ° C.

(Attachability)
What cut off the double-sided adhesive sheet obtained by the Example and the comparative example in the size of 80 mm x 80 mm was made into the test piece. A piece of the above-mentioned test piece from which one of the release liners was peeled was attached to a PET film in an edge shape using a commercially available double-sided pressure-sensitive adhesive sheet on one surface of stepped glass (a 0.5 mm step was provided 3, 4 and 5 (hereinafter sometimes referred to as “lower glass”) were bonded to the glass surface on the side having a level difference. And the structure A which has a laminated structure of lower glass and a double-sided adhesive sheet was obtained. Next, the release liner of the double-sided pressure-sensitive adhesive sheet in Structure A is peeled off, and Structure A is applied to one side of a 100 mm × 100 mm size glass plate (sometimes referred to as “upper glass”). A vacuum press was applied for 5 seconds under the conditions of .3 MPa and vacuum degree 100 Pa for bonding. And the structure B which has a laminated structure of an upper glass, a double-sided adhesive sheet, and a lower glass was obtained. Thereafter, the structure B was put into an autoclave and autoclaved at a temperature of 50 ° C. and a pressure of 0.5 MPa for 15 minutes. After the autoclave treatment, the structure B was removed from the autoclave, the structure B was visually observed, and the bonding property of the double-sided pressure-sensitive adhesive sheet was evaluated based on the following criteria. In addition, since the air gap in the conventional vehicle-mounted optical product with a bezel is 0.5-1.5 mm normally, evaluation was performed using the lower glass which provided the step of 0.5 mm.
○ (Good): No air bubbles on the entire surface of the double-sided pressure-sensitive adhesive sheet and bonding is possible × (bad): The double-sided pressure-sensitive adhesive sheet does not reach the upper glass

(Adhesive reliability)
What cut off in the size of 50 mm x 100 mm from the double-sided adhesive sheet obtained by the Example and the comparative example was made into the test piece. Peel off one of the release liners of the above test piece, affix the test piece to soda glass (thickness: 0.7 mm), remove the other release liner of the test piece, PPMA (trade name "MR200", Mitsubishi Rayon Co., Ltd. Made to a thickness of 1 mm) to prepare a laminate having a configuration of [soda glass / double-sided pressure-sensitive adhesive sheet / PMMA], and left for 15 minutes under an environment of temperature 50 ° C. and 0.50 MPa. The laminate after left to stand was further left to stand in an environment of 95 ° C. for 100 hours, and the laminate after left to stand was visually observed. The adhesion reliability was evaluated as follows.
((Good): no foaming and no peeling 可能 (usable): partially foaming is present × (poor): some foaming and peeling

DESCRIPTION OF SYMBOLS 1 Automotive optical product 2 Plastic cover 3 Printing layer 4 Adhesive sheet 5 Glass sensor 6 Form 7 Bezel 8 Optical double-sided adhesive sheet 9a of the present invention Polarizing plate 9b Polarizing plate 10 Liquid crystal display 11 On cell or in cell 100 Lower glass (with a step Glass)
101 Glass plate 102 Double-sided adhesive sheet 103 PET film

Claims (7)

It has at least an adhesive layer in which the elastic modulus at 95 ° C. is 4.0 × 10 ⁴ Pa or more and the elastic modulus at 25 ° C. is 1.0 × 10 ⁶ Pa or less
The pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive layer containing an acrylic polymer as a base polymer,
The acrylic polymer is a polymer composed of (meth) acrylic acid alkyl ester, a monomer having a nitrogen atom and / or a monomer having a hydroxyl group in the molecule as a monomer component, and all of the acrylic polymer is composed The total of the proportions of the nitrogen atom-containing monomer and the hydroxyl group-containing monomer in the monomer component is 15% by weight or more,
A double-sided pressure-sensitive adhesive sheet for optical use, which has a thickness of 500 μm or more and is used for an optical product for vehicles. The optical double-sided pressure-sensitive adhesive sheet according to claim 1 , wherein the optical double-sided pressure-sensitive adhesive sheet has a pressure-sensitive adhesive layer on both sides of a substrate. The optical double-sided pressure-sensitive adhesive sheet according to claim 2 , wherein the thickness of the substrate is 75 μm or more. The optical double-sided pressure-sensitive adhesive sheet according to claim 2 or 3 , wherein the in-plane retardation of the substrate is 4000 nm or more. The optical double-sided pressure-sensitive adhesive sheet according to claim 2 or 3 , wherein the in-plane retardation of the substrate is 20 nm or less. The optical double-sided pressure-sensitive adhesive sheet according to any one of claims 1 to 5 , which is for full lamination used to fill an air gap in an on-vehicle optical product. An on-vehicle optical product comprising the optical double-sided pressure-sensitive adhesive sheet according to any one of claims 1 to 6 .

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