JP6605562B2 - Adhesive sheet - Google Patents

Description

  The present invention relates to an adhesive sheet.

  The pressure-sensitive adhesive sheet is used for the purpose of adhesion between adherends, fixation of articles to the adherends, reinforcement of the adherends, and the like by firmly adhering to the adherends. Conventionally, a pressure-sensitive adhesive sheet exhibiting high adhesive strength has been used for such purposes from the initial stage of application. Recently, as in Patent Documents 1 to 3, a pressure-sensitive adhesive sheet has been proposed that exhibits a low adhesive strength at the initial stage of application to an adherend and can greatly increase the adhesive strength. According to the pressure-sensitive adhesive sheet having such characteristics, before the increase of the adhesive strength, it exerts a re-attachability (reworkability) useful for suppressing a decrease in the yield due to a mistake in sticking of the pressure-sensitive adhesive sheet or a failure to stick, and the adhesive strength is increased. After the rise, strong adhesiveness suitable for the intended use of the pressure-sensitive adhesive sheet can be exhibited.

JP 2014-224227 A Japanese Patent No. 5890596 Japanese Patent No. 5951153

  By the way, depending on the usage mode of the adhesive sheet, after proceeding to the subsequent process, there may be a request for rework due to a mistake in pasting or failure of pasting or occurrence of misalignment due to the influence of the subsequent process. obtain. In such a case, during the period in which reworkability is required for the pressure-sensitive adhesive sheet attached to the adherend, for example, the operation of an apparatus (conveying apparatus, inspection apparatus, other various processing apparatuses, etc.) used in the manufacturing process is involved. A temperature of about 40 ° C. to 50 ° C. may be applied to the pressure-sensitive adhesive sheet due to an accidental factor such as an influence of heat generation, exhaust heat from a nearby apparatus, and a temperature increase in a manufacturing environment. Then, this invention aims at providing the adhesive sheet which can maintain rework property even if the temperature of about 50 degreeC is added at the initial stage of sticking to a to-be-adhered body, and can raise an adhesive force large after that. .

According to this specification, an adhesive sheet including an adhesive layer is provided. The pressure-sensitive adhesive layer contains a polymer A and a polymer B that is a copolymer of a monomer having a polyorganosiloxane skeleton and a (meth) acrylic monomer. In the polymer B, the glass transition temperature T _m1 based on the composition of the (meth) acrylic monomer is 50 ° C. or higher and 100 ° C. or lower. The pressure-sensitive adhesive sheet was bonded to a stainless steel plate and then the adhesive strength N ₈₀ after heating at 80 ° C. for 5 minutes was 5 times the adhesive strength N ₅₀ after being bonded to a stainless steel plate and held at 50 ° C. for 30 minutes. That's it.

The pressure-sensitive adhesive sheet of such a structure, by a glass transition temperature T _m1 comprises a polymer B is less than 100 ° C. or higher 50 ° C., say adhesive strength N _{80 (hereinafter} relative adhesive strength N _50, also called "post-heating adhesive strength" .) Can be increased by a factor of 5 (ie, N ₈₀ / N ₅₀ ≧ 5). Thereby, even in a usage mode in which a temperature of about 50 ° C. can be applied at the initial stage of application, good reworkability is exhibited, and the adhesive force can be greatly increased by subsequent heating or the like.

In the pressure-sensitive adhesive sheet according to some embodiments, the relationship between the pressure-sensitive adhesive strength N ₅₀ and the pressure-sensitive adhesive strength N ₂₃ after being allowed to stand at 23 ° C. for 30 minutes after being bonded to a stainless steel plate is represented by the following formula: (N ₅₀ / N ₂₃ ) <10; According to such an adhesive sheet, there is little difference in adhesive strength (and reworkability) between the case where it is maintained at room temperature in the initial stage of application and the case where it is exposed to a temperature up to about 50 ° C. From the viewpoint of easiness.

In some embodiments, the glass transition temperature TA of the polymer _A can be, for example, −80 ° C. or higher and lower than 0 ° C. PSA sheet disclosed herein may be suitably implemented using a polymer A having such a glass transition temperature T _A.

In some embodiments, the glass transition temperature TB of the polymer _B can be, for example, −10 ° C. or higher and 10 ° C. or lower. PSA sheet disclosed herein may be suitably implemented with a polymer B having such a glass transition temperature T _B.

  In some embodiments, the polymer B may have a copolymerization ratio of a monomer having a homopolymer glass transition temperature higher than 170 ° C. of 30% by weight or less. The pressure-sensitive adhesive sheet disclosed herein can be suitably implemented using the polymer B having such a copolymer composition.

  In some embodiments, the pressure-sensitive adhesive layer may include more than 0 parts by weight and less than 10 parts by weight of a crosslinking agent with respect to 100 parts by weight of the polymer A. By using a cross-linking agent, the initial adhesive strength can be effectively adjusted in a temperature range up to about 50 ° C. Thereby, it exists in the tendency which becomes easy to obtain the adhesive sheet which reconciles suitably the rework property of a sticking initial stage, and the strong adhesiveness after adhesive force raise.

  In some embodiments, as the polymer B, a polymer having a weight average molecular weight (Mw) of 10,000 or more and 50,000 or less can be preferably used. According to the polymer B having Mw in the above range, an adhesive sheet having a low adhesive force at the initial stage of application and a high adhesive force after heating is easily obtained.

  In some embodiments, the content of the polymer B in the pressure-sensitive adhesive layer may be in the range of 0.05 to 20 parts by weight with respect to 100 parts by weight of the polymer A. When the content is in the above range, an adhesive sheet having a low adhesive force at the initial stage of application and a high adhesive force after heating is easily obtained.

  The pressure-sensitive adhesive sheet disclosed herein comprises a support substrate having a first surface and a second surface, and the pressure-sensitive adhesive layer is laminated on at least the first surface of the support substrate, that is, with a substrate. It can be implemented in the form of an adhesive sheet. Such a pressure-sensitive adhesive sheet with a substrate can have good handleability and processability. As the support substrate, for example, a substrate having a thickness of 30 μm or more can be preferably used.

  A combination of the above-described elements as appropriate can also be included in the scope of the invention for which protection by patent is sought by this patent application.

It is sectional drawing which shows typically the structure of the adhesive sheet which concerns on one Embodiment. It is sectional drawing which shows typically the structure of the adhesive sheet which concerns on other one Embodiment. It is sectional drawing which shows typically the structure of the adhesive sheet which concerns on other one Embodiment.

Hereinafter, preferred embodiments of the present invention will be described. Matters other than those specifically mentioned in the present specification and necessary for the implementation of the present invention are based on the teachings on the implementation of the invention described in the present specification and the common general technical knowledge at the time of filing. It can be understood by a trader. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field.
In the following drawings, members / parts having the same action may be described with the same reference numerals, and redundant descriptions may be omitted or simplified. In addition, the embodiments described in the drawings are schematically illustrated in order to clearly explain the present invention, and do not necessarily accurately represent the size and scale of a product actually provided.

  In this specification, “acrylic polymer” refers to a polymer containing a monomer unit derived from a (meth) acrylic monomer in the polymer structure, and is typically a monomer derived from a (meth) acrylic monomer. A polymer containing a unit in a proportion exceeding 50% by weight. The (meth) acrylic monomer means a monomer having at least one (meth) acryloyl group in one molecule. Here, the “(meth) acryloyl group” means an acryloyl group and a methacryloyl group comprehensively. Therefore, the concept of the (meth) acrylic monomer mentioned here may include both a monomer having an acryloyl group (acrylic monomer) and a monomer having a methacryloyl group (methacrylic monomer). Similarly, in this specification, “(meth) acrylic acid” means acrylic acid and methacrylic acid, and “(meth) acrylate” means acrylate and methacrylate.

<Structural example of adhesive sheet>
The pressure-sensitive adhesive sheet disclosed herein includes a pressure-sensitive adhesive layer. The pressure-sensitive adhesive sheet disclosed herein may be in the form of a pressure-sensitive adhesive sheet with a base material in which the pressure-sensitive adhesive layer is laminated on one side or both sides of a support base material. Form may be sufficient. Hereinafter, the supporting substrate may be simply referred to as “substrate”.

  The structure of the adhesive sheet which concerns on one Embodiment is typically shown in FIG. This pressure-sensitive adhesive sheet 1 is a single-sided pressure-sensitive adhesive sheet with a base material comprising a sheet-like support base material 10 having a first surface 10A and a second surface 10B, and a pressure-sensitive adhesive layer 21 provided on the first surface 10A side. It is configured. The pressure-sensitive adhesive layer 21 is fixed to the first surface 10 </ b> A side of the support substrate 10. The pressure-sensitive adhesive sheet 1 is used by attaching a pressure-sensitive adhesive layer 21 to an adherend. As shown in FIG. 1, the pressure-sensitive adhesive sheet 1 before use (that is, before being attached to an adherend) has a surface (adhesive surface) 21 </ b> A of the pressure-sensitive adhesive layer 21 that is peelable at least on the side facing the pressure-sensitive adhesive layer 21. It can be a constituent element of the pressure-sensitive adhesive sheet with release liner 100 in a form in contact with the release liner 31 on the surface (release surface). As the release liner 31, for example, a sheet-like base material (liner base material) provided with a release layer made of a release treatment agent on one side so that the one side becomes a release surface can be preferably used. Alternatively, the release liner 31 is omitted, and the pressure-sensitive adhesive sheet 21 is wound on the second surface 10B of the support substrate 10 by winding the pressure-sensitive adhesive sheet 1 using the support substrate 10 in which the second surface 10B is the release surface. It may be in the form of contact (roll form). When the pressure-sensitive adhesive sheet 1 is attached to the adherend, the release liner 31 or the second surface 10B of the support substrate 10 is peeled off from the pressure-sensitive adhesive surface 21A, and the exposed pressure-sensitive adhesive surface 21A is pressure-bonded to the adherend.

  The structure of the pressure-sensitive adhesive sheet according to another embodiment is schematically shown in FIG. The pressure-sensitive adhesive sheet 2 is provided on the sheet-like support base material 10 having the first surface 10A and the second surface 10B, the pressure-sensitive adhesive layer 21 provided on the first surface 10A side, and the second surface 10B side. And a pressure-sensitive adhesive layer 22. The pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer) 21 is fixed to the first surface 10A of the support base material 10, and the pressure-sensitive adhesive layer (second pressure-sensitive adhesive layer) 22 is fixed to the second surface 10B of the support base material 10, respectively. Yes. The pressure-sensitive adhesive sheet 2 is used by sticking the pressure-sensitive adhesive layers 21 and 22 to different places on the adherend. The places where the adhesive layers 21 and 22 are affixed may be different places in different members, or different places in a single member. As shown in FIG. 2, the pressure-sensitive adhesive sheet 2 before use has a surface (first pressure-sensitive adhesive surface) 21 </ b> A of the pressure-sensitive adhesive layer 21 and a surface (second pressure-sensitive adhesive surface) 22 </ b> A of the pressure-sensitive adhesive layer 22. 22 may be a constituent element of the pressure-sensitive adhesive sheet 200 with a release liner in a form in contact with the release liners 31 and 32 each having a release surface on the side facing the surface 22. As the release liners 31 and 32, for example, a sheet-shaped base material (liner base material) that is configured so that one side becomes a release surface by providing a release layer with a release treatment agent on one side is preferably used. obtain. Alternatively, the release liner 32 is omitted, the release liner 31 having both surfaces as release surfaces is used, and this and the adhesive sheet 2 are overlapped and wound in a spiral shape, whereby the second adhesive surface 22A is released into the release liner 31. You may comprise the adhesive sheet with a release liner of the form (roll form) contact | abutted to the back surface of this.

  Furthermore, the structure of the adhesive sheet which concerns on other one Embodiment is typically shown in FIG. The pressure-sensitive adhesive sheet 3 is configured as a base material-less double-sided pressure-sensitive adhesive sheet composed of a pressure-sensitive adhesive layer 21. The pressure-sensitive adhesive sheet 3 includes a first pressure-sensitive adhesive surface 21 </ b> A configured by one surface (first surface) of the pressure-sensitive adhesive layer 21 and a second pressure-sensitive adhesive surface configured by the other surface (second surface) of the pressure-sensitive adhesive layer 21. 21B is used by being attached to a different part of the adherend. As shown in FIG. 3, the pressure-sensitive adhesive sheet 3 before use has a release liner 31, 32 in which the first pressure-sensitive adhesive surface 21 </ b> A and the second pressure-sensitive adhesive surface 21 </ b> B are at least the side facing the pressure-sensitive adhesive layer 21. It may be a constituent element of the pressure-sensitive adhesive sheet 300 with a release liner in a form in contact with the. Alternatively, the release liner 32 is omitted, the release liner 31 having both surfaces as release surfaces is used, and this and the adhesive sheet 3 are overlapped and wound in a spiral shape, whereby the second adhesive surface 21B is released into the release liner 31. You may comprise the adhesive sheet with a release liner of the form (roll form) contact | abutted to the back surface of this.

  In addition, what is called an adhesive tape, an adhesive film, an adhesive label, etc. may be included in the concept of an adhesive sheet here. The pressure-sensitive adhesive sheet may be in the form of a roll or sheet, and may be cut or punched into an appropriate shape depending on the application or usage. The pressure-sensitive adhesive layer in the technology disclosed herein is typically formed continuously, but is not limited thereto, and may be formed in a regular or random pattern such as a dot shape or a stripe shape. Good.

<Adhesive layer>
The pressure-sensitive adhesive sheet disclosed herein includes a pressure-sensitive adhesive layer containing polymer A and polymer B which is a copolymer of a monomer having a polyorganosiloxane skeleton and a (meth) acrylic monomer. Such a pressure-sensitive adhesive layer may be formed from a pressure-sensitive adhesive composition containing polymer A or a precursor thereof and polymer B. The form of the pressure-sensitive adhesive composition is not particularly limited, and may be various forms such as a water dispersion type, a solvent type, a hot melt type, and an active energy ray curable type (for example, a photocurable type).

(Polymer A)
Examples of the polymer A include acrylic polymers, rubber polymers, polyester polymers, urethane polymers, polyether polymers, silicone polymers, polyamide polymers, fluorine polymers and the like known in the field of pressure-sensitive adhesives at room temperature. One kind or two or more kinds of various polymers exhibiting rubber elasticity can be used.

Glass transition temperature T _A of the polymer A may be not particularly limited, the preferred characteristics in the PSA sheet disclosed herein is selected to obtain. In some embodiments, polymer A with T _A less than 0 ° C. may be preferably employed. Such a pressure-sensitive adhesive containing the polymer A exhibits appropriate fluidity (for example, the mobility of the polymer chain contained in the pressure-sensitive adhesive), and thus has both low initial adhesiveness and strong adhesiveness after heating. Suitable for realization of adhesive sheet. PSA sheet disclosed herein, _{T A} is less than -10 ° C., less than -20 ° C., can be preferably carried out using polymer A below -30 ° C. or less than -35 ° C.. In some embodiments, _{T A} may be less than -40 ° C., may be less than -50 ° C.. The lower limit of T _A is not particularly limited. From the viewpoint of material availability improve cohesion ease and pressure-sensitive adhesive layer, usually, T _A is -80 ° C. or higher, can be preferably used a -70 ° C. or higher, or -65 ° C. or more polymers A. From the viewpoint of suppressing the increase of N _50, in some embodiments, _{T A} may be for example -63 ° C. or higher may be at -55 ° C. or higher may be at -50 ° C. or higher, or at -45 ° C. or higher .

Here, in this specification, the glass transition temperature (Tg) of a polymer is a nominal value described in literatures, catalogs, or the like, or is based on the Fox equation based on the composition of monomer components used in the preparation of the polymer. The required Tg. The formula of Fox is a relational expression between Tg of a copolymer and glass transition temperature Tgi of a homopolymer obtained by homopolymerizing each of the monomers constituting the copolymer, as shown below.
1 / Tg = Σ (Wi / Tgi)
In the above Fox formula, Tg is the glass transition temperature (unit: K) of the copolymer, Wi is the weight fraction of monomer i in the copolymer (copolymerization ratio based on weight), and Tgi is the homopolymer of monomer i. Represents the glass transition temperature (unit: K). When the polymer of interest related to the identification of Tg is a homopolymer, the Tg of the homopolymer and the Tg of the polymer of interest coincide.

  As the glass transition temperature of the homopolymer used for the calculation of Tg, the values described in known materials are used. Specifically, the figures are listed in “Polymer Handbook” (3rd edition, John Wiley & Sons, Inc., 1989). The highest value is adopted for the monomers whose values are listed in the Polymer Handbook.

As the glass transition temperature of a homopolymer of a monomer not described in the Polymer Handbook, values obtained by the following measurement method are used except for a monomer having a polyorganosiloxane skeleton.
Specifically, a reactor equipped with a thermometer, a stirrer, a nitrogen introduction tube and a reflux condenser is charged with 100 parts by weight of monomer, 0.2 part by weight of 2,2′-azobisisobutyronitrile and acetic acid as a polymerization solvent. 200 parts by weight of ethyl is added and stirred for 1 hour while flowing nitrogen gas. After removing oxygen in the polymerization system in this way, the temperature is raised to 63 ° C. and the reaction is carried out for 10 hours. Next, the mixture is cooled to room temperature to obtain a homopolymer solution having a solid concentration of 33% by weight. Next, this homopolymer solution is cast-coated on a release liner and dried to prepare a test sample (sheet-like homopolymer) having a thickness of about 2 mm. This test sample is punched into a disk shape with a diameter of 7.9 mm, sandwiched between parallel plates, and shear strain at a frequency of 1 Hz using a viscoelasticity tester (manufactured by TA Instruments Japan, model name “ARES”). The viscoelasticity is measured by the shear mode at a temperature rising rate of −70 ° C. to 150 ° C. and 5 ° C./min, and the temperature corresponding to the peak top temperature of tan δ is defined as Tg of the homopolymer.

  Moreover, about the monomer which has polyorganosiloxane frame | skeleton, the value obtained by performing DSC (differential scanning calorimetry) about this monomer, More specifically, the value obtained according to the method as described in the Example mentioned later is used. The Fox equation is applied as the glass transition temperature of the monomer having the polyorganosiloxane skeleton.

Although not particularly limited, it is appropriate that the weight average molecular weight (Mw) of the polymer A is usually about 5 × 10 ⁴ or more. According to such a polymer A of Mw, it is easy to obtain a pressure-sensitive adhesive exhibiting good cohesiveness. In some embodiments, the Mw of polymer A may be, for example, 10 × 10 ⁴ or more, 20 × 10 ⁴ or more, or 30 × 10 ⁴ or more. The Mw of the polymer A is usually about 500 × 10 ⁴ or less. This Mw polymer A is easy to form a pressure-sensitive adhesive exhibiting moderate fluidity (polymer chain mobility), and is suitable for realizing a pressure-sensitive adhesive sheet having low adhesive strength at the initial stage of application and high adhesive strength after heating. ing.

  In this specification, the Mw of the polymer A and the polymer B can be determined in terms of polystyrene by gel permeation chromatography (GPC). More specifically, Mw can be measured according to the methods and conditions described in the examples described later.

  As the polymer A in the pressure-sensitive adhesive sheet disclosed herein, an acrylic polymer can be preferably employed. When an acrylic polymer is used as the polymer A, good compatibility with the polymer B tends to be easily obtained. Good compatibility between the polymer A and the polymer B is preferable because it can contribute to the reduction of the initial adhesive force and the improvement of the adhesive force after heating through the improvement of the mobility of the polymer B in the pressure-sensitive adhesive layer.

The acrylic polymer is, for example, a polymer containing 50% by weight or more of monomer units derived from (meth) acrylic acid alkyl ester, that is, 50% by weight or more of the total amount of monomer components for preparing the acrylic polymer (meta ) A polymer that is an alkyl acrylate. As the (meth) acrylic acid alkyl ester, a (meth) acrylic acid alkyl ester having a linear or branched alkyl group having 1 to 20 carbon atoms (that is, C _1-20 ) can be preferably used. Since it is easy to balance the characteristics, the proportion of the (meth) acrylic acid C _1-20 alkyl ester in the total amount of monomer components may be, for example, 50% by weight or more, 60% by weight or more, and 70% by weight or more. But you can. For the same reason, the proportion of the (meth) acrylic acid C _1-20 alkyl ester in the total amount of the monomer components may be, for example, 99.9% by weight or less, 98% by weight or less, or 95% by weight or less. . In some embodiments, the proportion of the (meth) acrylic acid C _1-20 alkyl ester in the total amount of monomer components may be, for example, 90% by weight or less, 85% by weight or less, or 80% by weight or less.

Non-limiting specific examples of the (meth) acrylic acid C _1-20 alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, ( N-butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, (meth) Hexyl acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, (meth ) Decyl acrylate, isomethyl (meth) acrylate, undecyl (meth) acrylate, (meth ) Dodecyl acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, stearyl (meth) acrylate, (meth) Examples include isostearyl acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate, and the like.

Among these, at least (meth) acrylic acid C _1-18 alkyl ester is preferably used, and at least (meth) acrylic acid C _1-14 alkyl ester is more preferably used. In some embodiments, the acrylic polymer is at least one selected from (meth) acrylic acid C _4-12 alkyl esters (preferably acrylic acid C _4-10 alkyl esters, such as acrylic acid C _6-10 alkyl esters). Can be contained as monomer units. For example, an acrylic polymer containing one or both of n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA) is preferred, and an acrylic polymer containing at least 2EHA is particularly preferred. Examples of other (meth) acrylic acid C _1-18 alkyl esters that can be preferably used include methyl acrylate, methyl methacrylate (MMA), n-butyl methacrylate (BMA), 2-ethylhexyl methacrylate (2EHMA). And isostearyl acrylate (ISTA).

  The monomer unit that constitutes the acrylic polymer is composed of (meth) acrylic acid alkyl ester as the main component and, if necessary, another monomer (copolymerizable monomer) copolymerizable with (meth) acrylic acid alkyl ester. May be included. As the copolymerizable monomer, a monomer having a polar group (for example, a carboxy group, a hydroxyl group, a nitrogen atom-containing ring, etc.) can be suitably used. A monomer having a polar group can serve to introduce a crosslinking point into the acrylic polymer or to increase the cohesive strength of the acrylic polymer. A copolymerizable monomer can be used individually by 1 type or in combination of 2 or more types.

Non-limiting specific examples of the copolymerizable monomer include the following.
Carboxy group-containing monomer: For example, acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid and the like.
Acid anhydride group-containing monomer: for example, maleic anhydride, itaconic anhydride.
Hydroxyl group-containing monomer: for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, (meth) acryl 4-hydroxybutyl acid, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxy Hydroxyalkyl (meth) acrylates such as methylcyclohexyl) methyl (meth) acrylate and the like.
Monomers containing sulfonic acid groups or phosphoric acid groups: for example, styrene sulfonic acid, allyl sulfonic acid, sodium vinyl sulfonate, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfone Propyl (meth) acrylate, (meth) acryloyloxynaphthalene sulfonic acid, 2-hydroxyethyl acryloyl phosphate, and the like.
Epoxy group-containing monomer: For example, epoxy group-containing acrylates such as glycidyl (meth) acrylate and (meth) acrylic acid-2-ethylglycidyl ether, allyl glycidyl ether, (meth) acrylic acid glycidyl ether, and the like.
Cyano group-containing monomer: For example, acrylonitrile, methacrylonitrile and the like.
Isocyanate group-containing monomer: For example, 2-isocyanatoethyl (meth) acrylate.
Amide group-containing monomer: for example, (meth) acrylamide; N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N, N-dipropyl (meth) acrylamide, N, N-diisopropyl (meth) N, N-dialkyl (meth) acrylamides such as acrylamide, N, N-di (n-butyl) (meth) acrylamide, N, N-di (t-butyl) (meth) acrylamide; N-ethyl (meth) N-alkyl (meth) acrylamides such as acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, Nn-butyl (meth) acrylamide; N-vinylcarboxylic amides such as N-vinylacetamide A monomer having a hydroxyl group and an amide group, for example, N- (2-hydro (Ciethyl) (meth) acrylamide, N- (2-hydroxypropyl) (meth) acrylamide, N- (1-hydroxypropyl) (meth) acrylamide, N- (3-hydroxypropyl) (meth) acrylamide, N- (2 N-hydroxyalkyl (meth) acrylamides such as -hydroxybutyl) (meth) acrylamide, N- (3-hydroxybutyl) (meth) acrylamide, N- (4-hydroxybutyl) (meth) acrylamide; alkoxy groups and amides A monomer having a group, for example, N-alkoxyalkyl (meth) acrylamide such as N-methoxymethyl (meth) acrylamide, N-methoxyethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide; N-dimethylaminopropi (Meth) acrylamide, N- (meth) acryloyl morpholine.
Monomers having a nitrogen atom-containing ring: for example, N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N- Vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N- (meth) acryloyl-2-pyrrolidone, N- (meth) acryloylpiperidine, N- (meth) acryloylpyrrolidine, N-vinylmorpholine, N-vinyl-3 -Morpholinone, N-vinyl-2-caprolactam, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, N-vinylpyrazole, N-vinylisoxazole, N-vinyl Thiazole, N-vinylisothiazole, N-vinylpyridazine (E.g., lactams such as N- vinyl-2-caprolactam).
Monomers having a succinimide skeleton: for example, N- (meth) acryloyloxymethylene succinimide, N- (meth) acryloyl-6-oxyhexamethylene succinimide, N- (meth) acryloyl-8-oxyhexamethylene succinimide, and the like.
Maleimides: For example, N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide and the like.
Itaconic imides: for example, N-methyl itaconimide, N-ethyl itaconimide, N-butyl itaconimide, N-octyl itaconimide, N-2-ethylhexylitaconimide, N-cyclohexyl leuconconimide, N-lauryl Itacone imide and the like.
Aminoalkyl (meth) acrylates: for example, aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, (meth) acrylic acid t -Butylaminoethyl.
Alkoxy group-containing monomer: for example, 2-methoxyethyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, (meth) acrylic acid (Meth) acrylic acid alkoxyalkylenes such as butoxyethyl and (meth) acrylic acid ethoxypropyl; (meth) acrylic acid alkoxyalkylene glycols such as (meth) acrylic acid methoxyethylene glycol and (meth) acrylic acid methoxypolypropylene glycol Kind.
Vinyl esters: For example, vinyl acetate, vinyl propionate and the like.
Vinyl ethers: For example, vinyl alkyl ethers such as methyl vinyl ether and ethyl vinyl ether.
Aromatic vinyl compound: For example, styrene, α-methylstyrene, vinyltoluene and the like.
Olefin: For example, ethylene, butadiene, isoprene, isobutylene and the like.
(Meth) acrylic acid ester having an alicyclic hydrocarbon group: for example, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate and the like.
(Meth) acrylic acid ester having an aromatic hydrocarbon group: for example, phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, benzyl (meth) acrylate and the like.
In addition, heterocycle-containing (meth) acrylates such as tetrahydrofurfuryl (meth) acrylate, halogen-containing (meth) acrylates such as vinyl chloride and fluorine-containing (meth) acrylate, silicon atoms such as silicone (meth) acrylate (Meth) acrylate, (meth) acrylic acid ester obtained from terpene compound derivative alcohol and the like.

  When such a copolymerizable monomer is used, the amount used is not particularly limited, but it is usually appropriate to be 0.01% by weight or more of the total amount of monomer components. From the viewpoint of better exhibiting the effect of using the copolymerizable monomer, the amount of the copolymerizable monomer used may be 0.1% by weight or more of the total amount of the monomer components, or 1% by weight or more. The amount of the copolymerizable monomer used can be 50% by weight or less, preferably 40% by weight or less, based on the total amount of the monomer components. Thereby, it can prevent that the cohesion force of an adhesive becomes high too much and can improve the tuck feeling in normal temperature (25 degreeC).

  In some embodiments, the acrylic polymer contains, as monomer units, an N-vinyl cyclic amide represented by the following general formula (M1) and a hydroxyl group-containing monomer (a monomer having a hydroxyl group and another functional group, such as a hydroxyl group and an amide). It is preferable to contain at least one monomer selected from the group consisting of:

ここで、上記一般式（Ｍ１）中のＲ^１は、２価の有機基である。

Here, R ¹ in the general formula (M1) is a divalent organic group.

  By using N-vinyl cyclic amide, the cohesive force and polarity of the pressure-sensitive adhesive can be adjusted, and the pressure-sensitive adhesive force can be improved after heating. Specific examples of the N-vinyl cyclic amide include 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-morpholinedione and the like. Particularly preferred are N-vinyl-2-pyrrolidone and N-vinyl-2-caprolactam.

  The amount of N-vinyl cyclic amide used is not particularly limited, but is usually 0.01% by weight or more (preferably 0.1% by weight or more, for example 0.5% by weight) of the total amount of monomer components for preparing the acrylic polymer. % Or more) is appropriate. In some embodiments, the amount of N-vinyl cyclic amide used may be 1% by weight or more, 5% by weight or more, or 10% by weight or more of the total amount of the monomer components. Further, from the viewpoint of improving tackiness at room temperature (25 ° C.) and improving flexibility at low temperatures, the amount of N-vinyl cyclic amide used is usually 40% by weight or less of the total amount of the monomer components. 30% by weight or less, or 20% by weight or less.

  By using a hydroxyl group-containing monomer, the cohesive force and polarity of the pressure-sensitive adhesive can be adjusted, and the pressure-sensitive adhesive force after heating can be improved. Further, the hydroxyl group-containing monomer can provide a reaction point with a cross-linking agent (for example, an isocyanate-based cross-linking agent) described later, and can increase the cohesive force of the pressure-sensitive adhesive by a cross-linking reaction.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, N- (2-hydroxyethyl) (meth) acrylamide, and the like. It can be preferably used. Among them, preferred examples include 2-hydroxyethyl acrylate (HEA), 4-hydroxybutyl acrylate (4HBA), and N- (2-hydroxyethyl) acrylamide (HEAA).

  The amount of the hydroxyl group-containing monomer used is not particularly limited, but is usually 0.01% by weight or more (preferably 0.1% by weight or more, for example 0.5% by weight or more) of the total amount of monomer components for preparing the acrylic polymer. ) Is appropriate. In some embodiments, the amount of the hydroxyl group-containing monomer used may be 1% by weight or more, 5% by weight or more, or 10% by weight or more of the total amount of the monomer components. In addition, from the viewpoint of improving tackiness at room temperature (25 ° C.) and improving flexibility at low temperature, it is appropriate that the amount of the hydroxyl group-containing monomer is usually 40% by weight or less of the total amount of the monomer components. % Or less, 20% or less, 10% or less, or 5% or less.

  In some embodiments, an N-vinyl cyclic amide and a hydroxyl group-containing monomer can be used in combination as the copolymerizable monomer. In this case, the total amount of the N-vinyl cyclic amide and the hydroxyl group-containing monomer can be, for example, 0.1% by weight or more based on the total amount of the monomer components for preparing the acrylic polymer. Alternatively, it may be 5% by weight or more, 10% by weight or more, 15% by weight or more, 20% by weight or more, or 25% by weight or more. The total amount of the N-vinyl cyclic amide and the hydroxyl group-containing monomer can be, for example, 50% by weight or less, and preferably 40% by weight or less, based on the total amount of the monomer components.

  The method for obtaining the acrylic polymer is not particularly limited, and various polymerization methods known as synthetic methods for acrylic polymers, such as solution polymerization method, emulsion polymerization method, bulk polymerization method, suspension polymerization method, photopolymerization method, etc. Can be adopted as appropriate. In some embodiments, a solution polymerization method may be preferably employed. The polymerization temperature at the time of performing the solution polymerization can be appropriately selected according to the type of monomer and solvent to be used, the type of polymerization initiator, and the like, for example, about 20 ° C to 170 ° C (typically 40 ° C to 140 ° C). C.).

  The initiator used for the polymerization can be appropriately selected from conventionally known thermal polymerization initiators, photopolymerization initiators, and the like according to the polymerization method. A polymerization initiator can be used individually by 1 type or in combination of 2 or more types.

  Examples of the thermal polymerization initiator include azo polymerization initiators (for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis-2-methylbutyronitrile, 2,2′-azobis ( 2-methylpropionic acid) dimethyl, 4,4′-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [2 -(5-Methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis (2-methylpropionamidine) disulfate, 2,2'-azobis (N, N'-dimethylene) Isobutylamidine) dihydrochloride, etc.); persulfates such as potassium persulfate; peroxide polymerization initiators (eg, dibenzoyl peroxide, t-butylperoxide) Reeto, lauroyl peroxide, etc.); redox polymerization initiators, and the like. Although the usage-amount of a thermal-polymerization initiator is not restrict | limited in particular, For example, 0.01 weight part-5 weight part with respect to 100 weight part of monomer components used for preparation of an acrylic polymer, Preferably 0.05 weight part- The amount can be in the range of 3 parts by weight.

  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, photoactivity Oxime photopolymerization initiator, benzoin photopolymerization initiator, benzyl photopolymerization initiator, benzophenone photopolymerization initiator, ketal photopolymerization initiator, thioxanthone photopolymerization initiator, acylphosphine oxide photopolymerization initiator An agent or the like can be used. Although the usage-amount of a photoinitiator is not restrict | limited in particular, For example, 0.01 weight part-5 weight part with respect to 100 weight part of monomer components used for preparation of an acrylic polymer, Preferably 0.05 weight part- The amount can be in the range of 3 parts by weight.

  In some embodiments, the acrylic polymer is a partial polymer (acrylic polymer) obtained by polymerizing a part of the monomer component by irradiating the mixture of the monomer component and the polymerization initiator as described above with ultraviolet (UV) irradiation. Polymer syrup) can be included in the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer. The pressure-sensitive adhesive composition containing the acrylic polymer syrup can be applied to a predetermined substrate and irradiated with ultraviolet rays to complete the polymerization. That is, the acrylic polymer syrup can be grasped as a precursor of the acrylic polymer. The pressure-sensitive adhesive layer disclosed herein can be formed using, for example, a pressure-sensitive adhesive composition containing the acrylic polymer syrup and polymer B.

(Polymer B)
The polymer B in the technique disclosed herein is a copolymer of a monomer having a polyorganosiloxane skeleton (hereinafter also referred to as “monomer S1”) and a (meth) acrylic monomer. Polymer B suppresses the adhesive strength at the initial stage of application to the adherend due to the low polarity and mobility of the polyorganosiloxane structure derived from monomer S1, and is applied by heating to a temperature higher than 50 ° C. or by aging. It can function as an adhesion increase retarder that increases the adhesion to the body. The monomer S1 is not particularly limited, and any monomer containing a polyorganosiloxane skeleton can be used. Monomer S1 promotes the uneven distribution of polymer B on the surface of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet before use (before sticking to the adherend) due to the low polarity derived from the structure, and light peeling at the initial stage of bonding Expresses low viscosity. As the monomer S1, a monomer having a polymerizable reactive group at one end can be preferably used. According to such copolymerization of the monomer S1 and the (meth) acrylic monomer, a polymer B having a polyorganosiloxane skeleton in the side chain is formed. The polymer B having such a structure tends to have a low initial adhesive strength and a high adhesive strength after heating due to the mobility and ease of movement of side chains.

ここで、上記一般式（１），（２）中のＲ^３は水素またはメチルであり、Ｒ^４はメチル基または１価の有機基であり、ｍおよびｎは０以上の整数である。 As the monomer S1, for example, a compound represented by the following general formula (1) or (2) can be used. More specifically, X-22-174ASX, X-22-2426, X-22-2475, KF-2012, etc. are mentioned as a single terminal reactive silicone oil made by Shin-Etsu Chemical Co., Ltd. Monomer S1 can be used individually by 1 type or in combination of 2 or more types.

Here, R ³ in the general formulas (1) and (2) is hydrogen or methyl, R ⁴ is a methyl group or a monovalent organic group, and m and n are integers of 0 or more.

  The functional group equivalent of the monomer S1 is, for example, preferably 700 g / mol or more and less than 15000 g / mol, more preferably 800 g / mol or more and less than 10000 g / mol, and more preferably 850 g / mol or more and less than 6000 g / mol. Is more preferable, and particularly preferably 1500 g / mol or more and less than 5000 g / mol. When the functional group equivalent of the monomer S1 is less than 700 g / mol, the initial adhesive force may not be sufficiently suppressed. When the functional group equivalent of the monomer S1 is 15000 g / mol or more, the increase in adhesive strength may be insufficient. When the functional group equivalent of the monomer S1 is within the above range, it is easy to adjust the compatibility (for example, compatibility with the polymer A) and mobility in the pressure-sensitive adhesive layer to an appropriate range, It becomes easy to realize an adhesive sheet that achieves a high level of strong adhesiveness after the increase in adhesive strength.

Here, “functional group equivalent” means the weight of the main skeleton (for example, polydimethylsiloxane) bonded per functional group. The title unit g / mol is converted to 1 mol of functional group. The functional group equivalent of the monomer S1 can be calculated from the spectral intensity of ¹ H-NMR (proton NMR) based on nuclear magnetic resonance (NMR), for example. Calculation of the functional group equivalent (g / mol) of the monomer S1 based on the spectrum intensity of ¹ H-NMR is based on a general structural analysis method related to ¹ H-NMR spectrum analysis, and if necessary, Patent No. 5951153. This can be done with reference to the description in the publication.

In addition, when using 2 or more types of monomers from which a functional group equivalent differs as the monomer S1, an arithmetic average value can be used as a functional group equivalent of the monomer S1. That is, the functional group equivalent of the monomer S1 composed of n types of monomers having different functional group equivalents (monomer S1 ₁ , monomer S1 ₂ ... Monomer S1 _n ) can be calculated by the following formula.
Functional group equivalent of the monomer S1 (g / mol) = (monomer S1 ₁ functional group equivalent × monomer S1 ₁ of the amount + monomer S1 ₂ functional group equivalent × monomer S1 ₂ of the amount + ... + monomer S1 _n Functional group equivalent × monomer S1 _n blending amount) / (monomer S1 ₁ blending amount + monomer S1 ₂ blending amount +... + Monomer S1 _n blending amount)

The content of the monomer S1 may be, for example, 5% by weight or more with respect to the total monomer components for preparing the polymer B, and is 10% by weight or more from the viewpoint of better exhibiting the effect as an adhesive increase retarder. Preferably, it may be 15% by weight or more, or 20% by weight or more. Further, the content of the monomer S1 is suitably 60% by weight or less with respect to all monomer components for preparing the polymer B from the viewpoint of polymerization reactivity and compatibility, and is 50% by weight or less. Alternatively, it may be 40% by weight or less, or 30% by weight or less. When the content of the monomer S1 is less than 5% by weight, the initial adhesive force may not be sufficiently suppressed. When the content of the monomer S1 is more than 60% by weight, the increase in adhesive strength may be insufficient.

  The monomer component used for the preparation of the polymer B includes a (meth) acrylic monomer copolymerizable with the monomer S1 in addition to the monomer S1. The mobility of the polymer B in the pressure-sensitive adhesive layer can be suitably adjusted by copolymerizing one or two or more (meth) acrylic monomers and the monomer S1. Copolymerization of the monomer S1 and the (meth) acrylic monomer can also help improve the compatibility between the polymer B and the polymer A (for example, an acrylic polymer).

In the polymer B in the technique disclosed herein, the composition of the (meth) acrylic monomer contained in the monomer component is such that the glass transition temperature T _m1 based on the composition of the (meth) acrylic monomer is 50 ° C. or higher and 100 ° C. or lower. It is preferable to set so that. According to the polymer B having T _m1 of 50 ° C. or higher, in the pressure-sensitive adhesive sheet containing the polymer B, the increase in N ₅₀ tends to be suppressed. According to the polymer B having a T _m1 of 50 ° C. or higher, the polymer B includes an improvement in the mobility and mobility of the polyorganosiloxane structure portion accompanying a temperature increase from room temperature to about 50 ° C. (meta) This is considered to be because it is effectively suppressed by the monomer unit derived from the acrylic monomer, and the low adhesiveness resulting from the presence of the polyorganosiloxane structure portion can be better maintained. When T _m1 is lower than 50 ° C., the effect of suppressing the increase in N ₅₀ decreases. Moreover, when T _m1 is higher than 100 ° C., the post-heating adhesive force (N ₈₀ ) tends to decrease. According to the polymer B having T _m1 of 50 ° C. or more and 100 ° C. or less, N ₈₀ can be greatly increased with respect to N ₅₀ . Therefore, the polymer B having a composition in which T _m1 is in the above range is suitable for realizing a pressure-sensitive adhesive sheet satisfying N ₈₀ / N ₅₀ ≧ 5.

In some embodiments, the glass transition temperature T _m1 may be, for example, 53 ° C. or higher, 56 ° C. or higher, 59 ° C. or higher, 62 ° C. or higher, 65 ° C. or higher, 68 ° C. or higher, or 70 degreeC or more may be sufficient. According to the polymer B having a higher T _{m1, the} effect of suppressing the increase in N ₅₀ tends to be larger. Further, from the viewpoint of facilitating the increase in adhesive strength by heating to a temperature range higher than 50 ° C., in some embodiments, T _m1 may be, for example, 100 ° C. or lower, 90 ° C. or lower, 85 ° C. It may be below or below 80 ° C. or below 80 ° C.

Here, the glass transition temperature T _m1 based on the composition of the (meth) acrylic monomer is based on the Fox formula based on the composition of only the (meth) acrylic monomer among the monomer components used for the preparation of the polymer B. The required Tg. T _m1 applies the above-described Fox formula for only the (meth) acrylic monomer among the monomer components used for the preparation of the polymer B, and the glass transition temperature of the homopolymer of each (meth) acrylic monomer It can be calculated from the weight fraction of each (meth) acrylic monomer in the total amount of the (meth) acrylic monomer. From the viewpoint of easily exerting the effect by appropriately setting _Tm1 , the total amount of the monomer S1 and the (meth) acrylic monomer in the total monomer components for preparing the polymer B is, for example, 50% by weight or more. It may be 70% by weight or more, 85% by weight or more, 90% by weight or more, 95% by weight or more, or substantially 100% by weight.

Glass transition temperature T _B of the polymer B can be not particularly limited, the preferred characteristics in the PSA sheet disclosed herein is selected to obtain. T _B of the polymer B may be, for example, less than 50 ° C., 30 ° C. or less, 20 ° C. or less, 15 ° C. or less, or 10 ° C. or less. When the T _{B of the} polymer B is lowered, the mobility of the polymer B is improved, and the adhesive force tends to be increased by heating in a temperature range higher than 50 ° C. Further, in some embodiments, _{T B} of the polymer B may be for example -40 ℃ or higher may be at -30 ° C. or higher may be at -20 ° C. or higher, or at -10 ° C. or higher. When T _{B of the} polymer B becomes high, N ₅₀ tends to be suppressed easily.

In some embodiments of the pressure-sensitive adhesive sheet disclosed herein, the polymer B preferably has a copolymerization ratio of a monomer having a glass transition temperature of higher than 170 ° C. of 30% by weight or less. Here, in the present specification, when the copolymerization ratio of the monomer is X weight% or less, unless otherwise specified, the copolymerization ratio of the monomer is 0% by weight, that is, the monomer is substantially copolymerized. It is a concept including a mode that is not. Moreover, being substantially not copolymerized means that the said monomer is not copolymerized at least intentionally. When the copolymerization ratio of the monomer having a glass transition temperature higher than 170 ° C. is high, the mobility of the polymer B tends to be insufficient, and it is difficult to increase the adhesive force by heating to a temperature range higher than 50 ° C. Can be. By glass transition temperature of the homopolymer is less than a high copolymerization ratio of the monomers from 170 ° C. 30 wt%, at least one of the effects of improving the enhancement and N _{50 /} N ₈₀ of the N ₈₀ can be realized.

In some embodiments, the composition of the monomer components for preparing the polymer B, as T _m1 is higher than T _B, i.e. T _m1 -T _B can be set to be larger than 0 ° C.. According to such a composition, the effect of adjusting the mobility of the polymer B is easily exhibited by the composition of the (meth) acrylic monomer contained in the monomer component. T _m1 -T _B can be, for example, 40 ° C. to 100 ° C. approximately, may be about 50 ° C. to 90 ° C., or at about 65 ° C. to 85 ° C..

From the viewpoint of easily controlling the mobility of the polymer B in the adhesive layer, in some embodiments, the composition of the monomer components for preparing the polymer B, in relation to the glass transition temperature T _A of the polymer A, T _m1 so that the higher 20 ° C. or higher than _{T a,} i.e. _T m1 -T _a can be set to be 20 ° C. or higher. In some _{embodiments, T} m1 -T _A may be, for example, a 50 ° C. to 130 DEG ° C., or at 60 ° C. to 120 ° C. of about or 70 ° C. to 120 ° C. approximately.

As a (meth) acrylic-type monomer which can be used for the monomer component for preparing the polymer B, (meth) acrylic-acid alkylester is mentioned, for example. For example, one or more of the monomers exemplified above as the (meth) acrylic acid alkyl ester that can be used when the polymer A is an acrylic polymer can be used as a copolymerization component of the polymer B. In some embodiments, polymer B is a (meth) acrylic acid C _4-12 alkyl ester (preferably (meth) acrylic acid C _4-10 alkyl ester, such as (meth) acrylic acid C _6-10 alkyl ester). At least one kind may be contained as a monomer unit. In some other embodiments, polymer B contains at least one methacrylic acid C _1-18 alkyl ester (preferably methacrylic acid C _1-14 alkyl ester, eg, methacrylic acid C _1-10 alkyl ester) as a monomer unit. Can do. The monomer unit constituting the polymer B can include, for example, one or more selected from MMA, BMA, and 2EHMA.

  Other examples of the (meth) acrylic monomer include (meth) acrylic acid esters having an alicyclic hydrocarbon group. For example, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, 1-adamantyl (meth) acrylate, or the like can be used. In some embodiments, polymer B may contain as monomer units at least one selected from dicyclopentanyl methacrylate, isobornyl methacrylate, and cyclohexyl methacrylate.

  The amount of the (meth) acrylic acid alkyl ester and the (meth) acrylic acid ester having an alicyclic hydrocarbon group is, for example, 10% by weight or more and 95% by weight with respect to all monomer components for preparing the polymer B. % Or less, 20% to 95% by weight, 30% to 90% by weight, 40% to 90% by weight, 50% It may be not less than 85% by weight. From the viewpoint of easy increase in adhesive strength by heating to a temperature higher than 50 ° C., the use of (meth) acrylic acid alkyl ester can be advantageous. In some embodiments, the amount of the (meth) acrylic acid ester having an alicyclic hydrocarbon group is 50% by weight of the total amount of (meth) acrylic monomers included in the monomer component for preparing the polymer B. It may be less than 30% by weight, less than 15% by weight, less than 10% by weight, or less than 5% by weight. It is not necessary to use a (meth) acrylic acid ester having an alicyclic hydrocarbon group.

In some embodiments, it is preferred that the monomer component for preparing polymer B comprises at least MMA. Copolymerizing MMA can be a useful tool to adjust T _m1 to the preferred range disclosed herein. Further, according to the polymer B copolymerized with MMA, a large pressure-sensitive adhesive sheet of N ₈₀ / N ₅₀ is easily obtained. The proportion of MMA in the total amount of (meth) acrylic monomers contained in the monomer component for preparing the polymer B may be, for example, 5% by weight or more, 10% by weight or more, or 20% by weight or more. It may be 30% by weight or more, or 40% by weight or more. In some embodiments, the proportion of MMA in the total amount of the (meth) acrylic monomer may be, for example, greater than 50 wt%, greater than 55 wt%, greater than 60 wt%, and 65 wt% It may be more than 70% by weight. Further, the ratio of MMA in the total amount of the (meth) acrylic monomer may be within a range where T _m1 is 100 ° C. or less, and is usually 95% by weight or less, and may be 90% by weight or less. 85 wt% or less.

  As another example of the monomer that can be included together with the monomer S1 as the monomer unit constituting the polymer B, the carboxyl group-containing monomer and acid anhydride group that are exemplified above as the monomer that can be used when the polymer A is an acrylic polymer Monomer, hydroxyl group-containing monomer, epoxy group-containing monomer, cyano group-containing monomer, isocyanate group-containing monomer, amide group-containing monomer, monomer having a nitrogen atom-containing ring, monomer having a succinimide skeleton, maleimides, itaconimides, (meth) acrylic Acid aminoalkyls, vinyl esters, vinyl ethers, olefins, (meth) acrylic acid esters having aromatic hydrocarbon groups, heterocyclic (meth) acrylates, halogen atom-containing (meth) acrylates, terpene compounds Resulting from the conductor alcohol (meth) acrylic acid ester.

  Other examples of monomers that can be included with the monomer S1 as the monomer unit constituting the polymer B include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di ( Oxyalkylene di (meth) acrylates such as (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, and tripropylene glycol di (meth) acrylate; monomers having a polyoxyalkylene skeleton, such as polyethylene glycol Have a polymerizable functional group such as (meth) acryloyl group, vinyl group or allyl group at one end of polyoxyalkylene chain such as polypropylene glycol A polymerizable polyoxyalkylene ether having an ether structure (alkyl ether, aryl ether, arylalkyl ether, etc.); methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, (meth ) Alkoxyalkyl (meth) acrylates such as butoxyethyl acrylate and ethoxypropyl (meth) acrylate; salts such as alkali metal salts of (meth) acrylate; multivalents such as trimethylolpropane tri (meth) acrylate ( (Meth) acrylate: vinylidene chloride, vinyl halide compounds such as (meth) acrylic acid-2-chloroethyl; 2-vinyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2- Oxazolines such as oxazoline -Containing monomers; (meth) acryloylaziridine, aziridine group-containing monomers such as (meth) acrylic acid-2-aziridinylethyl; (meth) acrylic acid-2-hydroxyethyl, (meth) acrylic acid-2-hydroxypropyl, Hydroxyl group-containing vinyl monomers such as adducts of lactones with (meth) acrylic acid-2-hydroxyethyl; fluorine-containing vinyl monomers such as fluorine-substituted (meth) acrylic acid alkyl esters; 2-chloroethyl vinyl ether, monochlorovinyl acetate, etc. Reactive halogen-containing vinyl monomers such as vinyltrimethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane, allyltrimethoxysilane, trimethoxysilylpropylallylamine, 2-methoxyethoxytrimethoxysilane Monomer; and the like can be given like; macromonomers having a radically polymerizable vinyl group in the monomer ends obtained by polymerizing a vinyl group. These can be copolymerized with the monomer S1 alone or in combination.

  The Mw of the polymer B is not particularly limited. The Mw of the polymer B may be 1000 or more, for example, or 5000 or more. If the Mw of the polymer B is too low, the increase in adhesive strength may be insufficient. In some preferred embodiments, the Mw of the polymer B may be, for example, 10,000 or more, 12000 or more, 15000 or more, 17000 or more, or 20000 or more. Moreover, Mw of the polymer B may be 100,000 or less, for example, and may be 70,000 or less. If the Mw of the polymer B is too high, the initial adhesive force may not be sufficiently suppressed. In some preferred embodiments, the Mw of polymer B may be, for example, 50000 or less, less than 50000, less than 40000, less than 35000, 30000 or less, 28000 or less, or 25000 or less. . When the Mw of the polymer B is within the range of any one of the upper limit value and the lower limit value described above, it is easy to adjust the compatibility and mobility in the pressure-sensitive adhesive layer to an appropriate range, and good reworkability and adhesion at the initial stage of application It becomes easy to realize a pressure-sensitive adhesive sheet that achieves a high level of strong adhesiveness after increasing the force.

  The polymer B can be prepared, for example, by polymerizing the above-described monomers by a known method such as a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a suspension polymerization method, or a photopolymerization method.

  A chain transfer agent can be used to adjust the molecular weight of the polymer B. Examples of the chain transfer agent used include compounds having a mercapto group such as octyl mercaptan, lauryl mercaptan, t-nonyl mercaptan, t-dodecyl mercaptan, mercaptoethanol, α-thioglycerol; thioglycolic acid, methyl thioglycolate, Ethyl thioglycolate, propyl thioglycolate, butyl thioglycolate, t-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, isooctyl thioglycolate, decyl thioglycolate, dodecyl thioglycolate, ethylene Thioglycolates such as thioglycolate of glycol, thioglycolate of neopentyl glycol, thioglycolate of pentaerythritol; α-methyl Rustyrene dimer; and the like.

  The amount of the chain transfer agent used is not particularly limited, but is usually 0.05 to 20 parts by weight, preferably 0.1 to 15 parts by weight, based on 100 parts by weight of the monomer. More preferably, it contains 0.2 to 10 parts by weight. Thus, the polymer B of a suitable molecular weight can be obtained by adjusting the addition amount of a chain transfer agent. In addition, a chain transfer agent can be used individually by 1 type or in combination of 2 or more types.

  Although it does not specifically limit, the usage-amount of the polymer B can be 0.1 weight part or more with respect to the usage-amount of the polymer A 100 weight part, for example, 0.3 from a viewpoint of obtaining a higher effect. It may be greater than or equal to parts by weight, may be greater than or equal to 0.4 parts by weight, and may be greater than or equal to 0.5 parts by weight. From the viewpoint of improving reworkability and the like, in some embodiments, the amount of the polymer B used relative to 100 parts by weight of the polymer A may be 1 part by weight or more, 2 parts by weight or more, or 3 parts by weight or more. Moreover, the usage-amount of the polymer B with respect to 100 weight part of polymers A may be 75 weight part or less, for example, may be 60 weight part or less, and may be 50 weight part or less. From the viewpoint of avoiding excessive reduction in the cohesive force of the pressure-sensitive adhesive layer, in some embodiments, the amount of the polymer B used relative to 100 parts by weight of the polymer A can be, for example, 40 parts by weight or less, and 35 parts by weight or less. 30 parts by weight or less or 25 parts by weight or less. From the viewpoint of obtaining a higher adhesive strength after heating, in some embodiments, the amount of the polymer B used may be 20 parts by weight or less, 17 parts by weight or less, 15 parts by weight or less, and 10 parts by weight. Or less. In some embodiments of the pressure-sensitive adhesive sheet disclosed herein, the amount of the polymer B used relative to 100 parts by weight of the polymer A may be, for example, less than 10 parts by weight, may be 8 parts by weight or less, may be 5 parts by weight or less, or 5 parts by weight. May be less than 4 parts by weight, or 4 parts by weight or less, or 3 parts by weight or less.

  The pressure-sensitive adhesive layer may contain a polymer (arbitrary polymer) other than the polymer A and the polymer B as necessary as long as the performance of the pressure-sensitive adhesive sheet disclosed herein is not significantly impaired. The amount of such optional polymer used is usually 20% by weight or less of the total polymer component contained in the pressure-sensitive adhesive layer, and may be 15% by weight or less, or 10% by weight or less. In some embodiments, the amount of the optional polymer used may be 5% by weight or less, 3% by weight or less, or 1% by weight or less of the total polymer component. The pressure-sensitive adhesive layer may contain substantially no polymer other than polymer A and polymer B.

(Crosslinking agent)
A cross-linking agent may be used in the pressure-sensitive adhesive layer as necessary for the purpose of adjusting cohesion. As the crosslinking agent, a crosslinking agent known in the field of pressure-sensitive adhesives can be used. For example, an epoxy-based crosslinking agent, an isocyanate-based crosslinking agent, a silicone-based crosslinking agent, an oxazoline-based crosslinking agent, an aziridine-based crosslinking agent, or a silane-based crosslinking agent. Crosslinking agents, alkyl etherified melamine crosslinking agents, metal chelate crosslinking agents and the like can be mentioned. In particular, an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, and a metal chelate-based crosslinking agent can be preferably used. A crosslinking agent can be used individually by 1 type or in combination of 2 or more types.

  Specifically, examples of the isocyanate-based crosslinking agent include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenyl (meth) diisocyanate, hydrogenated diphenyl (meth) diisocyanate. , Tetramethylxylylene diisocyanate, naphthalene diisocyanate, triphenyl (meth) triisocyanate, polymethylene polyphenyl isocyanate, and adducts of these with polyols such as trimethylolpropane. Alternatively, a compound having at least one isocyanate group and one or more unsaturated bonds in one molecule, specifically, 2-isocyanatoethyl (meth) acrylate or the like may be used as an isocyanate-based crosslinking agent. Can do. These can be used individually by 1 type or in combination of 2 or more types.

  Epoxy crosslinking agents include bisphenol A, epichlorohydrin type epoxy resin, ethylene glycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol glycidyl ether, trimethylolpropane tri Mention glycidyl ether, diglycidyl aniline, diamine glycidyl amine, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, etc. Can do. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of the metal chelate compound include aluminum, iron, tin, titanium, and nickel as metal components, and acetylene, methyl acetoacetate, and ethyl lactate as chelate components. These can be used individually by 1 type or in combination of 2 or more types.

The amount used in the case of using the crosslinking agent is not particularly limited, and can be, for example, an amount exceeding 0 part by weight with respect to 100 parts by weight of the polymer A. Moreover, the usage-amount of a crosslinking agent can be 0.01 weight part or more with respect to 100 weight part of polymers A, and it is preferable to set it as 0.05 weight part or more. By increasing the amount of the crosslinking agent used, the adhesive strength at the initial stage of application is suppressed, and the reworkability tends to be improved. In some embodiments, the amount of crosslinking agent used relative to 100 parts by weight of polymer A may be 0.1 parts by weight or more, 0.5 parts by weight or more, or 1 part by weight or more. Good. On the other hand, from the viewpoint of avoiding a decrease in tack due to excessive cohesive strength improvement, the amount of the crosslinking agent used relative to 100 parts by weight of the polymer A is usually suitably 15 parts by weight or less, and may be 10 parts by weight or less. It may be 5 parts by weight or less. The fact that the amount of the crosslinking agent used is not too large can be advantageous from the viewpoint of easily realizing a pressure-sensitive adhesive sheet having a high N ₈₀ / N ₅₀ .

  The technique disclosed herein can be preferably implemented in an embodiment using at least an isocyanate-based crosslinking agent as the crosslinking agent. From the viewpoint of facilitating the realization of an adhesive sheet having both good reworkability at the initial stage of application and strong adhesiveness after an increase in adhesive strength, in some embodiments, the amount of isocyanate-based crosslinking agent used relative to 100 parts by weight of polymer A is: For example, the amount may be 0.1 to 5 parts by weight, may be 0.3 to 4 parts by weight, or may be 0.5 to 3 parts by weight.

Although not particularly limited, when an isocyanate-based crosslinking agent is used in a configuration in which the pressure-sensitive adhesive layer includes a hydroxyl group-containing monomer as a monomer unit, the amount of hydroxyl-containing monomer used W _OH relative to the amount of isocyanate-based crosslinking agent used W _NCO is: The amount of W _OH / W _NCO can be 2 or more on a weight basis. Thus, by increasing the amount of the hydroxyl group-containing monomer used relative to the isocyanate-based crosslinking agent, a crosslinked structure suitable for greatly increasing the post-heating adhesive strength relative to the initial adhesive strength can be formed. In some embodiments, W _OH / W _NCO may be 3 or greater, 5 or greater, 10 or greater, 20 or greater, or 30 or greater. It may be 50 or more. The upper limit of W _OH / W _NCO is not particularly limited. W _OH / W _NCO may be, for example, 500 or less, 200 or less, or 100 or less.

  In order to make any of the above-described crosslinking reactions proceed more effectively, a crosslinking catalyst may be used. As the crosslinking catalyst, for example, a tin-based catalyst (particularly dioctyltin dilaurate) can be preferably used. The amount of the crosslinking catalyst used is not particularly limited, and can be, for example, about 0.0001 to 1 part by weight with respect to 100 parts by weight of the polymer A.

A polyfunctional monomer may be used for the pressure-sensitive adhesive layer as necessary. The polyfunctional monomer can be used for the purpose of adjusting the cohesive force by being used in place of the crosslinking agent as described above or in combination with the crosslinking agent. For example, in a pressure-sensitive adhesive layer formed from a photocurable pressure-sensitive adhesive composition, a polyfunctional monomer can be preferably used.
Examples of the multifunctional monomer include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, Pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,12-dodecane Diol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylol methane tri (meth) acrylate, allyl (meth) acrylate, vinyl Le (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyl diol (meth) acrylate, hexyl di (meth) acrylate. Among these, trimethylolpropane tri (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and dipentaerythritol hexa (meth) acrylate can be preferably used. A polyfunctional monomer can be used individually by 1 type or in combination of 2 or more types.

The amount of the polyfunctional monomer used varies depending on the molecular weight, the number of functional groups, and the like, but it is usually appropriate to be in the range of about 0.01 to 3.0 parts by weight with respect to 100 parts by weight of the polymer A. . In some embodiments, the amount of the polyfunctional monomer used may be, for example, 0.02 parts by weight or more, or 0.03 parts by weight or more with respect to 100 parts by weight of the polymer A. By increasing the usage amount of the polyfunctional monomer, the adhesive strength at the initial stage of application is suppressed, and the reworkability tends to be improved. On the other hand, from the viewpoint of avoiding a decrease in tack due to excessive cohesion, the amount of the polyfunctional monomer used may be 2.0 parts by weight or less with respect to 100 parts by weight of the polymer A, and even 1.0 part by weight or less. It may be 0.5 parts by weight or less. The fact that the amount of the polyfunctional monomer used is not too large may be advantageous from the viewpoint of easily realizing a pressure-sensitive adhesive sheet having a high N ₈₀ / N ₅₀ .

(Tackifying resin)
The pressure-sensitive adhesive layer can contain a tackifier resin as necessary. The tackifying resin is not particularly limited. For example, rosin tackifying resin, terpene tackifying resin, phenol tackifying resin, hydrocarbon tackifying resin, ketone tackifying resin, polyamide tackifying resin, Examples thereof include an epoxy tackifying resin and an elastomer tackifying resin. Tackifying resin can be used individually by 1 type or in combination of 2 or more types.

Examples of rosin-based tackifier resins include unmodified rosins such as gum rosin, wood rosin and tall oil rosin (raw rosin), and modified rosins modified by polymerization, disproportionation, hydrogenation, etc. Polymerized rosin, stabilized rosin, disproportionated rosin, fully hydrogenated rosin, partially hydrogenated rosin and other chemically modified rosins), and various rosin derivatives.
Examples of the rosin derivative include:
A rosin phenolic resin obtained by thermally polymerizing rosins (unmodified rosin, modified rosin, various rosin derivatives, etc.) by adding phenol with an acid catalyst;
Ester compounds of rosin obtained by esterifying unmodified rosin with alcohol (unmodified rosin ester), modified rosins such as polymerized rosin, stabilized rosin, disproportionated rosin, fully hydrogenated rosin, partially hydrogenated rosin, alcohols Rosin ester resins such as modified rosin ester compounds esterified by (polymerized rosin ester, stabilized rosin ester, disproportionated rosin ester, fully hydrogenated rosin ester, partially hydrogenated rosin ester, etc.);
An unsaturated fatty acid-modified rosin resin obtained by modifying an unmodified rosin or a modified rosin (polymerized rosin, stabilized rosin, disproportionated rosin, fully hydrogenated rosin, partially hydrogenated rosin, etc.) with an unsaturated fatty acid;
Unsaturated fatty acid-modified rosin ester resin obtained by modifying rosin ester resin with unsaturated fatty acid;
Carboxyl group in unmodified rosin, modified rosin (polymerized rosin, stabilized rosin, disproportionated rosin, fully hydrogenated rosin, partially hydrogenated rosin, etc.), unsaturated fatty acid modified rosin resin and unsaturated fatty acid modified rosin ester resin Rosin alcohol resin obtained by reducing
Examples thereof include non-modified rosin, modified rosin, and metal salts of rosin resins (particularly rosin ester resins) such as various rosin derivatives.

  Examples of terpene-based tackifier resins include terpene resins such as α-pinene polymers, β-pinene polymers, dipentene polymers, and modified terpene resins (phenol-modified, aromatic-modified, hydrogenated-modified). Modified terpene resins such as terpene phenol resins, styrene modified terpene resins, aromatic modified terpene resins, hydrogenated terpene resins, and the like.

  Examples of phenolic tackifier resins include condensates of various phenols (eg, phenol, m-cresol, 3,5-xylenol, p-alkylphenol, resorcin, etc.) and formaldehyde (eg, alkylphenolic resins, xyleneformaldehyde). Resin), a resol obtained by addition reaction of the phenols and formaldehyde with an alkali catalyst, and a novolak obtained by condensation reaction of the phenols and formaldehyde with an acid catalyst.

  Examples of hydrocarbon tackifying resins include aliphatic hydrocarbon resins, aromatic hydrocarbon resins, aliphatic cyclic hydrocarbon resins, aliphatic / aromatic petroleum resins (styrene-olefin copolymers, etc. ), Various hydrocarbon resins such as aliphatic / alicyclic petroleum resins, hydrogenated hydrocarbon resins, coumarone resins, coumarone indene resins, and the like.

  Examples of commercially available polymerized rosin esters that can be preferably used include trade names “Pencel D-125”, “Pencel D-135”, “Pencel D-160”, “Pencel KK”, “Pencel” manufactured by Arakawa Chemical Industries, Ltd. C ”and the like are exemplified, but not limited thereto.

  Commercially available products of terpene phenolic resins that can be preferably used are trade names “YS Polystar S-145”, “YS Polystar G-125”, “YS Polystar N125”, “YS Polystar U-115” manufactured by Yashara Chemical Co., Ltd. The trade names “Tamanol 803L” and “Tamanol 901” manufactured by Arakawa Chemical Industries, Ltd., the trade name “Sumilite Resin PR-12603” manufactured by Sumitomo Bakelite Co., Ltd. and the like are exemplified, but not limited thereto.

  The content of the tackifier resin is not particularly limited, and can be set so that appropriate adhesive performance is exhibited depending on the purpose and application. The content of the tackifier resin relative to 100 parts by weight of the polymer A (when two or more tackifier resins are included, the total amount thereof) can be, for example, about 5 to 500 parts by weight.

As the tackifier resin, those having a softening point (softening temperature) of about 80 ° C. or more (preferably about 100 ° C. or more, for example, about 120 ° C. or more) can be preferably used. According to the tackifying resin having a softening point equal to or higher than the lower limit value described above, a pressure-sensitive adhesive sheet satisfying N ₈₀ / N ₅₀ ≧ 5 is easily obtained. The upper limit of the softening point is not particularly limited, and can be, for example, about 200 ° C. or lower (typically 180 ° C. or lower). In addition, the softening point of tackifying resin can be measured based on the softening point test method (ring ball method) prescribed | regulated to JISK2207.

  In addition, the pressure-sensitive adhesive layer in the technique disclosed herein is a leveling agent, a plasticizer, a softening agent, a colorant (dye, pigment, etc.), a filler, and an antistatic agent as long as the effects of the present invention are not significantly hindered. Further, known additives that can be used for the pressure-sensitive adhesive, such as an anti-aging agent, an ultraviolet absorber, an antioxidant, a light stabilizer, and a preservative, may be included as necessary.

  The pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive sheet disclosed herein can be a cured layer of the pressure-sensitive adhesive composition. That is, the pressure-sensitive adhesive layer is formed by applying (for example, applying) a pressure-sensitive adhesive composition such as a water dispersion type, a solvent type, a photo-curing type, or a hot-melt type to an appropriate surface, and then appropriately performing a curing treatment. obtain. When two or more kinds of curing treatments (drying, crosslinking, polymerization, cooling, etc.) are performed, these can be performed simultaneously or over a plurality of stages. In an adhesive composition using a partially polymerized monomer component (acrylic polymer syrup), a final copolymerization reaction is typically performed as the curing treatment. That is, the partial polymer is subjected to a further copolymerization reaction to form a complete polymer. For example, if it is a photocurable adhesive composition, light irradiation is implemented. If necessary, curing treatment such as cross-linking and drying may be performed. For example, when it is necessary to dry with a photocurable adhesive composition, it is good to perform photocuring after drying. In the pressure-sensitive adhesive composition using a completely polymerized product, typically, as the curing treatment, treatments such as drying (heat drying) and crosslinking are performed as necessary.

  Application of the pressure-sensitive adhesive composition can be carried out using a conventional coater such as a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, spray coater and the like.

  The thickness of the pressure-sensitive adhesive layer is not particularly limited, and can be, for example, 1 μm or more. In some embodiments, the thickness of the pressure-sensitive adhesive layer may be, for example, 3 μm or more, 5 μm or more, 8 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, or more than 20 μm. Due to the increase in the thickness of the pressure-sensitive adhesive layer, the adhesive strength after heating tends to increase. In some embodiments, the thickness of the pressure-sensitive adhesive layer may be, for example, 300 μm or less, 200 μm or less, 150 μm or less, 100 μm or less, 70 μm or less, 50 μm or less, or 40 μm. It may be the following. That the thickness of the pressure-sensitive adhesive layer is not too large can be advantageous from the viewpoint of reducing the thickness of the pressure-sensitive adhesive sheet and preventing cohesive failure of the pressure-sensitive adhesive layer. In the case of the pressure-sensitive adhesive sheet having the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer on the first surface and the second surface of the substrate, the thickness of the pressure-sensitive adhesive layer described above is at least the thickness of the first pressure-sensitive adhesive layer. Can be applied to. The thickness of the second pressure-sensitive adhesive layer can be selected from the same range. Further, in the case of a baseless pressure-sensitive adhesive sheet, the thickness of the pressure-sensitive adhesive sheet matches the thickness of the pressure-sensitive adhesive layer.

  Although it does not specifically limit, it is suitable that the gel fraction of the adhesive which comprises an adhesive layer is normally in the range of 20.0%-99.0%, and 30.0%-90. It is desirable to be in the range of 0%. By setting the gel fraction within the above range, it becomes easy to realize a pressure-sensitive adhesive sheet that achieves a high level of reworkability at the initial stage of application and strong adhesiveness after an increase in adhesive force. The gel fraction is measured by the following method.

[Measurement of gel fraction]
About 0.1 g of a pressure-sensitive adhesive sample (weight Wg ₁ ) is wrapped in a purse-like shape with a porous polytetrafluoroethylene membrane (weight Wg ₂ ) having an average pore diameter of 0.2 μm, and the mouth is bound with an octopus thread (weight Wg ₃ ). As the porous polytetrafluoroethylene membrane, a trade name “Nitoflon (registered trademark) NTF1122” (Nitto Denko Corporation, average pore diameter 0.2 μm, porosity 75%, thickness 85 μm) or its equivalent is used. This wrap is immersed in 50 mL of ethyl acetate, and kept at room temperature (typically 23 ° C.) for 7 days to elute the sol content (ethyl acetate soluble content) in the adhesive out of the membrane. Next, the packet is taken out and wiped off the ethyl acetate adhering to the outer surface, and then the packet is dried at 130 ° C. for 2 hours, and the weight (Wg ₄ ) of the packet is measured. By substituting each value into the following equation, it is possible to calculate the gel fraction G _C of the pressure-sensitive adhesive.
Gel fraction G _C (%) = [(Wg ₄ −Wg ₂ −Wg ₃ ) / Wg ₁ ] × 100

<Support base material>
The pressure-sensitive adhesive sheet according to some embodiments may be in the form of a pressure-sensitive adhesive sheet with a base material provided with a pressure-sensitive adhesive layer on one side or both sides of a support base material. The material of the support base material is not particularly limited, and can be appropriately selected according to the purpose of use or usage of the pressure-sensitive adhesive sheet. Non-limiting examples of substrates that can be used include polyolefin films based on polyolefins such as polypropylene and ethylene-propylene copolymers, polyester films based on polyesters such as polyethylene terephthalate and polybutylene terephthalate, Plastic films such as polyvinyl chloride films mainly composed of polyvinyl chloride; foam sheets made of foams such as polyurethane foam, polyethylene foam, polychloroprene foam; various fibrous materials (natural fibers such as hemp and cotton, Synthetic fibers such as polyester and vinylon, semi-synthetic fibers such as acetate, etc.) Woven and non-woven fabrics of single or mixed spinning, etc .; paper such as Japanese paper, fine paper, kraft paper, crepe paper; aluminum foil, Metal foil such as copper foil; That. The base material of the structure which compounded these may be sufficient. Examples of such a composite substrate include a substrate having a structure in which a metal foil and the plastic film are laminated, a plastic substrate reinforced with inorganic fibers such as glass cloth, and the like.

  As the base material of the pressure-sensitive adhesive sheet disclosed herein, various film base materials can be preferably used. The film substrate may be a porous substrate such as a foam film or a non-woven sheet, or may be a non-porous substrate, a porous layer and a non-porous layer, May be a base material having a laminated structure. In some embodiments, as the film substrate, a film containing a resin film capable of maintaining its shape independently (independent or independent) as a base film can be preferably used. Here, the “resin film” means a resin film having a non-porous structure and typically containing substantially no bubbles (voidless). Therefore, the said resin film is the concept distinguished from a foam film and a nonwoven fabric. As the resin film, a resin film that can maintain its shape independently (independent or independent) can be preferably used. The resin film may have a single-layer structure or a multilayer structure having two or more layers (for example, a three-layer structure).

  Examples of the resin material constituting the resin film include polyester, polyolefin, nylon 6, nylon 66, polyamide (PA) such as partially aromatic polyamide, polyimide (PI), polyamideimide (PAI), and polyetheretherketone (PEEK). ), Polyethersulfone (PES), polyphenylene sulfide (PPS), polycarbonate (PC), polyurethane (PU), ethylene-vinyl acetate copolymer (EVA), polytetrafluoroethylene (PTFE) and other fluororesins, acrylic resins Resins such as polyacrylate, polystyrene, polyvinyl chloride, and polyvinylidene chloride can be used. The resin film may be formed using a resin material containing one kind of such resin alone, or may be formed using a resin material in which two or more kinds are blended. Good. The resin film may be unstretched or stretched (for example, uniaxially stretched or biaxially stretched).

  Preferable examples of the resin material constituting the resin film include polyester resins, PPS resins, and polyolefin resins. Here, the polyester-based resin refers to a resin containing polyester in a proportion exceeding 50% by weight. Similarly, a PPS resin refers to a resin containing PPS in a proportion exceeding 50% by weight, and a polyolefin-based resin refers to a resin containing a polyolefin in a proportion exceeding 50% by weight.

  As the polyester resin, typically, a polyester resin containing as a main component a polyester obtained by polycondensation of a dicarboxylic acid and a diol is used.

  Examples of the dicarboxylic acid constituting the polyester include phthalic acid, isophthalic acid, terephthalic acid, 2-methyl terephthalic acid, 5-sulfoisophthalic acid, 4,4′-diphenyl dicarboxylic acid, and 4,4′-diphenyl ether dicarboxylic acid. 4,4′-diphenylketone dicarboxylic acid, 4,4′-diphenoxyethanedicarboxylic acid, 4,4′-diphenylsulfone dicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2, Aromatic dicarboxylic acids such as 6-naphthalenedicarboxylic acid and 2,7-naphthalenedicarboxylic acid; alicyclic dicarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid Malonic acid, succinic acid, glutaric acid, adipic acid, Aliphatic dicarboxylic acids such as melicic acid, suberic acid, azelaic acid, sebacic acid, and dodecanoic acid; unsaturated dicarboxylic acids such as maleic acid, maleic anhydride, and fumaric acid; And the like, and the like. These can be used individually by 1 type or in combination of 2 or more types. Aromatic dicarboxylic acids are preferred from the standpoint of strength and the like. Among these, preferred dicarboxylic acids include terephthalic acid and 2,6-naphthalenedicarboxylic acid. For example, 50% by weight or more (for example, 80% by weight or more, typically 95% by weight or more) of the dicarboxylic acid constituting the polyester is terephthalic acid, 2,6-naphthalenedicarboxylic acid, or a combination thereof. Is preferred. The dicarboxylic acid may be substantially composed of only terephthalic acid, substantially only 2,6-naphthalenedicarboxylic acid, or substantially only terephthalic acid and 2,6-naphthalenedicarboxylic acid.

  Examples of the diol constituting the polyester include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,4-butanediol, Aliphatic diols such as 1,6-hexanediol, 1,8-octanediol, polyoxytetramethylene glycol; 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, 1,4 -Cyclohexane dimethylol and other alicyclic diols, xylylene glycol, 4,4'-dihydroxybiphenyl, 2,2-bis (4'-hydroxyphenyl) propane, bis (4-hydroxyphenyl) sulfur Aromatic diols such emissions; and the like. These can be used individually by 1 type or in combination of 2 or more types. Of these, aliphatic diols are preferable from the viewpoint of transparency and the like, and ethylene glycol is particularly preferable. The proportion of the aliphatic diol (preferably ethylene glycol) in the diol constituting the polyester is preferably 50% by weight or more (for example, 80% by weight or more, typically 95% by weight or more). The diol may be substantially composed only of ethylene glycol.

  Specific examples of the polyester resin include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polybutylene naphthalate, and the like.

  As the polyolefin resin, one kind of polyolefin can be used alone, or two or more kinds of polyolefins can be used in combination. The polyolefin may be, for example, an α-olefin homopolymer, a copolymer of two or more α-olefins, a copolymer of one or more α-olefins with another vinyl monomer, and the like. Specific examples include polyethylene (PE), polypropylene (PP), poly-1-butene, poly-4-methyl-1-pentene, ethylene-propylene copolymers such as ethylene propylene rubber (EPR), ethylene-propylene- Examples include butene copolymers, ethylene-butene copolymers, ethylene-vinyl alcohol copolymers, and ethylene-ethyl acrylate copolymers. Both low density (LD) polyolefins and high density (HD) polyolefins can be used. Examples of polyolefin resin films include unstretched polypropylene (CPP) film, biaxially stretched polypropylene (OPP) film, low density polyethylene (LDPE) film, linear low density polyethylene (LLDPE) film, and medium density polyethylene (MDPE). Examples thereof include a film, a high-density polyethylene (HDPE) film, a polyethylene (PE) film obtained by blending two or more kinds of polyethylene (PE), and a PP / PE blend film obtained by blending polypropylene (PP) and polyethylene (PE).

  Specific examples of the resin film that can be preferably used as the base film of the pressure-sensitive adhesive sheet disclosed herein include PET film, PEN film, PPS film, PEEK film, CPP film, and OPP film. Examples of preferable base films from the viewpoint of strength and dimensional stability include PET films, PEN films, PPS films, and PEEK films. A PET film and a PPS film are particularly preferable from the viewpoint of availability of the base material, and the PET film is particularly preferable.

  In the resin film, a light stabilizer, an antioxidant, an antistatic agent, a colorant (dye, pigment, etc.), a filler, a slip agent, an antiblocking agent and the like are known as long as the effect of the present invention is not significantly hindered. These additives can be blended as necessary. The compounding quantity of an additive is not specifically limited, According to the use etc. of an adhesive sheet, it can set suitably.

  The method for producing the resin film is not particularly limited. For example, conventionally known general resin film forming methods such as extrusion molding, inflation molding, T-die casting, and calendar roll molding can be appropriately employed.

  The substrate may be substantially composed of such a base film. Alternatively, the base material may include an auxiliary layer in addition to the base film. Examples of the auxiliary layers include optical property adjusting layers (for example, colored layers and antireflection layers), printed layers and laminate layers for imparting a desired appearance to the substrate, antistatic layers, undercoat layers, and release layers. And the like.

  The thickness of a base material is not specifically limited, It can select according to the intended purpose, usage condition, etc. of an adhesive sheet. The thickness of the substrate can be, for example, 1000 μm or less. In some embodiments, the thickness of the base material may be, for example, 500 μm or less, 300 μm or less, 250 μm or less, and 200 μm from the viewpoint of the handleability and processability of the pressure-sensitive adhesive sheet. It may be the following. In some embodiments, from the viewpoint of downsizing and weight reduction of a product to which the pressure-sensitive adhesive sheet is applied, the thickness of the base material may be, for example, 160 μm or less, 130 μm or less, or 100 μm or less. Alternatively, it may be 90 μm or less, 70 μm or less, 50 μm or less, 25 μm or less, 10 μm or less, or 5 μm or less. When the thickness of the substrate is reduced, the flexibility of the pressure-sensitive adhesive sheet and the followability to the surface shape of the adherend tend to be improved. Further, from the viewpoint of handleability, workability, etc., the thickness of the substrate may be 2 μm or more, 5 μm or more, 10 μm or more, 20 μm or more, 25 μm or more, or more than 25 μm. In some embodiments, the thickness of the substrate may be, for example, 30 μm or more, 35 μm or more, 55 μm or more, 75 μm or more, or 120 μm or more. For example, in a pressure-sensitive adhesive sheet that can be used for the purpose of reinforcement, support, impact mitigation, etc. of an adherend, a substrate having a thickness of 30 μm or more can be preferably employed.

  For the first surface of the substrate, conventionally known surfaces such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, and formation of an undercoat layer by applying a primer (primer), if necessary. Processing may be performed. Such a surface treatment may be a treatment for improving the anchoring property of the pressure-sensitive adhesive layer to the base material. For example, in a pressure-sensitive adhesive sheet including a base material containing a resin film as a base film, a base material that has been subjected to such anchoring property improvement processing can be preferably employed. The above surface treatments can be applied alone or in combination. The composition of the primer used for forming the undercoat layer is not particularly limited, and can be appropriately selected from known ones. The thickness of the undercoat layer is not particularly limited, but is usually about 0.01 μm to 1 μm, preferably about 0.1 μm to 1 μm. Other treatments that can be applied to the first surface of the substrate as necessary include antistatic layer formation treatment, colored layer formation treatment, and printing treatment.

  When the pressure-sensitive adhesive sheet disclosed herein is in the form of a single-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer only on the first surface of the substrate, the second surface of the substrate is subjected to a peeling treatment or an antistatic treatment as necessary. A conventionally well-known surface treatment, such as these, may be given. For example, when the back surface of the base material is surface-treated with a release treatment agent (typically, by providing a release layer with a release treatment agent), the unwinding force of the pressure-sensitive adhesive sheet in the form of a roll is obtained. Can be lightened. As the release treatment agent, silicone release treatment agents, long-chain alkyl release treatment agents, olefin release treatment agents, fluorine release treatment agents, fatty acid amide release treatment agents, molybdenum sulfide, silica powder, and the like can be used. . In addition, for the purpose of improving printability, reducing light reflectivity, and improving overlayability, the second surface of the substrate is subjected to treatment such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, and alkali treatment. May be. In the case of a double-sided pressure-sensitive adhesive sheet, the second surface of the base material is subjected to the same surface treatment as described above as a surface treatment that can be performed on the first surface of the base material, if necessary. Also good. The surface treatment applied to the first surface of the substrate and the surface treatment applied to the second surface may be the same or different.

<Adhesive sheet>
(Adhesive sheet characteristics, etc.)
The pressure-sensitive adhesive sheet disclosed herein has a ratio of the pressure-sensitive adhesive force N ₈₀ (the pressure-sensitive adhesive force after heating) to the pressure-sensitive adhesive force N ₅₀ , that is, N ₈₀ / N ₅₀ is 5 or more. Even in the obtained usage mode, good reworkability is exhibited, and the adhesive force can be greatly increased by subsequent heating or the like. From the viewpoint of obtaining a higher effect, in some embodiments, N ₈₀ / N ₅₀ may be, for example, 7 or more, 10 or more, 15 or more, or 20 or more. The upper limit of N ₈₀ / N ₅₀ is not particularly limited, but may be, for example, 80 or less, 60 or less, 50 or less, or 40 or less from the viewpoint of ease of production and economical efficiency of the pressure-sensitive adhesive sheet. The pressure-sensitive adhesive sheet disclosed herein can be suitably implemented in an embodiment where N ₈₀ / N ₅₀ is, for example, 5 or more and 60 or less, 7 or more and 50 or less, or 10 or more and 40 or less.

Although not particularly limited, in some embodiments of the PSA sheet disclosed herein, the ratio of the adhesive strength _N 50 _[N / 25mm] for adhesion _N 23 _[N / 25mm], i.e. _N 50 _{/ N 23} May be, for example, less than 10, preferably less than 7, and may be less than 5 or less than 4. According to the pressure-sensitive adhesive sheet having a small N ₅₀ / N ₂₃ , good reworkability tends to be exhibited even in a usage mode in which a temperature of about 50 ° C. can be applied at the initial stage of application. The lower limit of N ₅₀ / N ₂₃ is not particularly limited, but is usually 1.0 or more, typically more than 1.0, for example, 1.2 or more.

Although not particularly limited, in some embodiments of the pressure-sensitive adhesive sheet disclosed herein, the ratio of the adhesive force N ₈₀ [N / 25 mm] to the adhesive force N ₂₃ [N / 25 mm], that is, N ₈₀ / N ₂₃ May be, for example, 7 or more, 10 or more, or 15 or more. According to the pressure-sensitive adhesive sheet having a large N ₈₀ / N ₂₃ , low adhesion at the initial stage of application and strong adhesion after the increase in adhesive force can be exhibited at a higher level. The pressure-sensitive adhesive sheet disclosed herein can also be suitably implemented in an embodiment where N ₈₀ / N ₂₃ is, for example, 20 or more, 30 or more, or 40 or more. The upper limit of N ₈₀ / N ₂₃ is not particularly limited, but may be, for example, 100 or less, 80 or less, 60 or less, or 50 or less from the viewpoint of ease of production and economic efficiency of the pressure-sensitive adhesive sheet.

Here, the adhesive strength N ₂₃ [N / 25 mm] was applied to a stainless steel (SUS) plate as an adherend and left for 30 minutes in an environment of 23 ° C. and 50% RH. It is grasped by measuring the peel strength by 180 ° peeling at a speed of 300 mm / min. The adhesive strength N ₅₀ [N / 25 mm] was pressed against a stainless steel (SUS) plate as an adherend and held in an environment of 50 ° C. for 30 minutes, and then left in an environment of 23 ° C. and 50% RH for 30 minutes. Later, it is grasped by measuring 180 ° peeling adhesive strength under the conditions of a peeling angle of 180 degrees and a tensile speed of 300 mm / min. The adhesive strength N ₈₀ [N / 25 mm] was applied to a SUS plate as an adherend and heated at 80 ° C. for 5 minutes, and then left in an environment of 23 ° C. and 50% RH for 30 minutes, and then the peeling angle was 180 degrees. It is grasped by measuring 180 ° peeling adhesive strength under the condition of a tensile speed of 300 mm / min. As the adherend, a SUS304BA plate is used in any of the measurements of the adhesive forces N ₂₃ , N ₅₀ , and N ₈₀ . In measurement, if necessary, an appropriate backing material (for example, a PET film having a thickness of about 25 μm) can be attached to the pressure-sensitive adhesive sheet to be measured for reinforcement. More specifically, the adhesive forces N ₂₃ , N ₅₀ , and N ₈₀ can be measured according to the method described in the examples described later.

Although not particularly limited, in some embodiments of the PSA sheet disclosed herein, the adhesive force _{N 23} of the pressure-sensitive adhesive sheet may be for example 2.0 N / 25 mm or less, less than 1.5 N / 25 mm Alternatively, it may be 1.2 N / 25 mm or less, 1.0 N / 25 mm or less, or 0.8 N / 25 mm or less. The low adhesion N ₂₃ are preferred in view of reworkability. The lower limit of the adhesive strength N ₂₃ is not particularly limited, for example. It can be 0.01 N / 25 mm or more. And joining workability to an adherend, from the viewpoint of the displacement prevention before rising adhesion, adhesive strength N _23, it is appropriate and usually, 0.1 N / 25 mm or more. From the viewpoint of improvement of post-heating adhesive strength, in some embodiments, the adhesive force _{N 23,} for example may be at 0.2 N / 25 mm or more, may be 0.3 N / 25 mm or more, 0.4 N / 25 mm or more It may be 0.5N / 25mm or more.

Although not particularly limited, in some embodiments of the pressure-sensitive adhesive sheet disclosed herein, the pressure-sensitive adhesive force N ₅₀ of the pressure-sensitive adhesive sheet may be, for example, 7 N / 25 mm or less, or 5 N / 25 mm or less. / 25 mm or less, 3.5 N / 25 mm or less, 3 N / 25 mm or less, 2.5 N / 25 mm or less, or 2 N / 25 mm or less. The low adhesion N ₅₀ is preferable from the viewpoint also exhibit good reworking property in the use aspect a temperature of about 50 ° C. to joining the initial get added. The lower limit of the adhesive strength N ₅₀ is not particularly limited. It may be 0.05 N / 25 mm or more. From the viewpoint of the displacement prevention before rising adhesion, adhesive strength _{N 50,} it is appropriate and usually, 0.1 N / 25 mm or more. From the viewpoint of improvement of post-heating adhesive strength, in some embodiments, the adhesive force _{N 50,} for example may be at 0.2 N / 25 mm or more, may be 0.5 N / 25 mm or more, 0.7 N / 25 mm or more But you can.

Although not particularly limited, in some embodiments of the pressure-sensitive adhesive sheet disclosed herein, the pressure-sensitive adhesive sheet N ₈₀ (adhesive strength after heating) may be, for example, 5 N / 25 mm or more, and 7 N / It may be 25 mm or more, 10 N / 25 mm or more, 13 N / 25 mm or more, 15 N / 25 mm or more, or 17 N / 25 mm or more. The upper limit of the adhesive strength after heating is not particularly limited. In some embodiments, the adhesive strength after heating may be, for example, 70 N / 25 mm or less, 50 N / 25 mm or less, or 40 N / 25 mm or less from the viewpoints of ease of manufacturing the adhesive sheet and economic efficiency.

Although not particularly limited, in some embodiments of the pressure-sensitive adhesive sheet disclosed herein, the difference between the pressure-sensitive adhesive force N ₅₀ [N / 25 mm] and the pressure-sensitive adhesive force N ₂₃ [N / 25 mm], that is, N ₅₀ −N. ₂₃ is usually preferably less than 5 N / 25 mm, for example, less than 4 N / 25 mm, less than 3 N / 25 mm, less than 2.5 N / 25 mm, or less than 2 N / 25 mm. It may be less than 5 N / 25 mm. According to the pressure-sensitive adhesive sheet having a small N ₅₀ -N ₂₃ , good reworkability tends to be exhibited even in a usage mode in which a temperature of about 50 ° C. can be applied at the initial stage of application. The lower limit of N ₅₀ -N ₂₃ is not particularly limited, but is usually 0 N / 25 mm or more, typically more than 0 N / 25 mm, for example, 0.2 N / 25 mm or more.

Although not particularly limited, the pressure-sensitive adhesive and wherein the adhesive force _N 50 of the PSA sheet disclosed [N / 25 mm] and the adhesive strength _N 80 _[N / 25mm] for the difference between the adhesive force _N 23 _[N / 25mm] The ratio of the difference from the force N ₅₀ [N / 25 mm], that is, (N ₈₀ −N ₅₀ ) / (N ₅₀ −N ₂₃ ) may be 2 or more, for example. The larger value of (N ₈₀ -N ₅₀ ) / (N ₅₀ -N ₂₃ ) means that the adhesive strength after heating is increased with respect to the initial adhesive strength in the application mode in which a temperature of about 50 ° C. can be applied. Means greater degree. In some _{embodiments, (N 80 -N 50) /} (N 50 -N 23) may be for example three or more may be 5 or more, may be 7 or more, may be 10 or more, may be 15 or more 20 or more. _(N 80 _{-N 50) /} the upper limit of (N 50 _{-N 23)} is not particularly limited, for example, it is a 100 or less.

  In addition, the adhesive force after a heating of the adhesive sheet disclosed here represents the characteristic of this adhesive sheet, and does not limit the use aspect of this adhesive sheet. In other words, the usage mode of the pressure-sensitive adhesive sheet disclosed herein is not limited to a mode in which heating is performed at 80 ° C. for 5 minutes, for example, a room temperature range (usually 20 ° C. to 30 ° C., typically 23 ° C. to 25 ° C. C.) can also be used in an embodiment in which the heat treatment is not particularly performed. Even in such a use mode, the adhesive strength increases over a long period of time, and a strong bonding can be realized. Moreover, the adhesive sheet disclosed here can accelerate | stimulate the raise of adhesive force by performing heat processing at the temperature higher than 50 degreeC at the arbitrary timings after sticking. The heating temperature in such heat treatment is not particularly limited, and can be set in consideration of workability, economy, heat resistance of the base material of the adhesive sheet and the adherend, and the like. The heating temperature may be, for example, less than 150 ° C, 120 ° C or less, 100 ° C or less, 80 ° C or less, or 70 ° C or less. Moreover, the said heating temperature can be 55 degreeC or more, 60 degreeC or more, or 70 degreeC or more, for example, may be 80 degreeC or more, and is good also as 100 degreeC or more. With a higher heating temperature, the adhesive force can be increased by a shorter processing time. The heating time is not particularly limited, and may be, for example, 1 hour or less, 30 minutes or less, 10 minutes or less, or 5 minutes or less. Or you may perform heat processing for a long period of time in the limit which does not produce remarkable heat deterioration to an adhesive sheet or a to-be-adhered body. Note that the heat treatment may be performed at once or may be performed in a plurality of times.

(Adhesive sheet with substrate)
When the pressure-sensitive adhesive sheet disclosed herein is in the form of a pressure-sensitive adhesive sheet with a substrate, the thickness of the pressure-sensitive adhesive sheet may be, for example, 1000 μm or less, 600 μm or less, 350 μm or less, or 250 μm or less. But you can. From the viewpoint of downsizing, lightening, thinning, etc. of the product to which the adhesive sheet is applied, in some embodiments, the thickness of the adhesive sheet may be, for example, 200 μm or less, and may be 175 μm or less, It may be 140 μm or less, 120 μm or less, or 100 μm or less (for example, less than 100 μm). The thickness of the pressure-sensitive adhesive sheet may be, for example, 5 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, 25 μm or more, or 30 μm or more from the viewpoint of handleability. In some embodiments, the thickness of the pressure-sensitive adhesive sheet may be, for example, 50 μm or more, 60 μm or more, 80 μm or more, 100 μm or more, or 130 μm or more. The upper limit of the thickness of an adhesive sheet is not specifically limited.
In addition, the thickness of an adhesive sheet means the thickness of the part affixed on a to-be-adhered body. For example, the pressure-sensitive adhesive sheet 1 having the configuration shown in FIG. 1 indicates the thickness from the pressure-sensitive adhesive surface 21 </ b> A of the pressure-sensitive adhesive sheet 1 to the second surface 10 </ b> B of the substrate 10, and does not include the thickness of the release liner 31.

  The pressure-sensitive adhesive sheet disclosed herein can be suitably implemented, for example, in a mode in which the thickness Ts of the support substrate is larger than the thickness Ta of the pressure-sensitive adhesive layer, that is, a mode in which Ts / Ta is larger than 1. Although not particularly limited, Ts / Ta may be, for example, 1.1 or more, 1.2 or more, 1.5 or more, or 1.7 or more. Also good. For example, in a pressure-sensitive adhesive sheet that can be used for the purpose of reinforcement, support, impact relaxation, etc. of an adherend, a good effect tends to be exhibited even if the pressure-sensitive adhesive sheet is thinned due to an increase in Ts / Ta. In some embodiments, Ts / Ta may be 2 or greater (eg, greater than 2), may be 3 or greater, and may be 4 or greater. Further, Ts / Ta can be set to 50 or less, for example, or 20 or less. From the viewpoint of easily exerting high post-heating adhesive force even if the pressure-sensitive adhesive sheet is thinned, Ts / Ta may be 10 or less, for example, or 8 or less.

The pressure-sensitive adhesive layer is preferably fixed to a support base material. In the adhesive sheet whose adhesive strength has increased after being attached to the adherend, the above-mentioned fixation is such that peeling at the interface between the adhesive layer and the supporting substrate does not occur when the adhesive sheet is peeled off from the adherend. This means that the pressure-sensitive adhesive layer exhibits a sufficient anchoring property with respect to the supporting substrate. According to the pressure-sensitive adhesive sheet with a base material in which the pressure-sensitive adhesive layer is fixed to the supporting base material, the adherend and the supporting base material can be firmly integrated. Thereby, for example, functions such as reinforcement, support and impact relaxation of the adherend can be effectively exhibited. As a suitable example of the pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer is fixed to the substrate, an adhesive strength (at least 5 N / 25 mm, preferably 10 N / 25 mm or more, more preferably 15 N / 25 mm or more after being attached to the adherend ( When peeling from the adherend while exhibiting a 180 ° peeling adhesive force (measured under conditions of a peeling angle of 180 degrees and a tensile speed of 300 mm / min), the pressure between the pressure-sensitive adhesive layer and the support substrate An adhesive sheet in which peeling (throwing destruction) does not occur. An adhesive sheet having an adhesive strength after heating (N ₈₀ ) of 15 N / 25 mm or more and which does not cause throwing damage when measuring the adhesive strength after heating corresponds to an adhesive sheet in which the adhesive layer is fixed to the substrate. This is a preferred example.

  The pressure-sensitive adhesive sheet disclosed herein forms, for example, a pressure-sensitive adhesive layer by bringing a liquid pressure-sensitive adhesive composition into contact with the first surface of the substrate and curing the pressure-sensitive adhesive composition on the first surface. And can be preferably manufactured by a method including the steps in this order. Curing of the pressure-sensitive adhesive composition may involve one or more of the pressure-sensitive adhesive composition, such as drying, crosslinking, polymerization, and cooling. Thus, according to the method of curing the liquid pressure-sensitive adhesive composition on the first surface of the substrate to form the pressure-sensitive adhesive layer, the cured pressure-sensitive adhesive layer is bonded to the first surface of the substrate. Compared with the method of disposing the pressure-sensitive adhesive layer on the first surface, the anchoring property of the pressure-sensitive adhesive layer to the substrate can be improved. By utilizing this, a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer fixed to a substrate can be suitably produced.

  In some embodiments, as a method of bringing the liquid pressure-sensitive adhesive composition into contact with the first surface of the substrate, a method of directly applying the pressure-sensitive adhesive composition to the first surface of the substrate can be employed. By bringing the first surface (adhesive surface) of the pressure-sensitive adhesive layer cured on the first surface of the substrate into contact with the release surface, the second surface of the pressure-sensitive adhesive layer is fixed to the first surface of the substrate. And the adhesive sheet of the structure which the 1st surface of this adhesive layer contact | abutted to the peeling surface can be obtained. As the release surface, the surface of the release liner, the back surface of the substrate after the release treatment, or the like can be used.

  Further, for example, in the case of a photocurable pressure-sensitive adhesive composition using a partially polymerized monomer component (acrylic polymer syrup), for example, after the pressure-sensitive adhesive composition is applied to a release surface, the applied pressure-sensitive adhesive The adhesive composition is covered with the first surface of the base material to bring the uncured pressure-sensitive adhesive composition into contact with the first surface of the base material, and in that state, between the first surface of the base material and the release surface. The pressure-sensitive adhesive layer may be formed by curing the sandwiched pressure-sensitive adhesive composition by irradiating light.

  In addition, the method illustrated above does not limit the manufacturing method of the adhesive sheet disclosed here. In manufacturing the pressure-sensitive adhesive sheet disclosed herein, an appropriate method capable of fixing the pressure-sensitive adhesive layer to the first surface of the substrate can be used singly or in combination of two or more. Examples of such methods include a method of forming a pressure-sensitive adhesive layer by curing a liquid pressure-sensitive adhesive composition on the first surface of the substrate as described above, and a pressure-sensitive adhesive layer on the first surface of the substrate. And a method of performing a surface treatment for improving the anchoring property. For example, when the anchoring property to the base material of the pressure-sensitive adhesive layer can be sufficiently improved by a method such as providing an undercoat layer on the first surface of the base material, the cured pressure-sensitive adhesive layer is attached to the first surface of the base material. You may manufacture an adhesive sheet by the method of bonding together. Moreover, the anchoring property to the base material of an adhesive layer can be improved also by selection of the material of a base material, or selection of a composition of an adhesive. Moreover, the anchoring property to the base material of this adhesive layer can be improved by applying temperature higher than room temperature to the adhesive sheet which has an adhesive layer on the 1st surface of a base material. The temperature applied to improve the anchoring property may be, for example, about 35 ° C. to 80 ° C., about 40 ° C. to 70 ° C. or more, or about 45 ° C. to 60 ° C.

The pressure-sensitive adhesive sheet disclosed herein has a first pressure-sensitive adhesive layer provided on the first surface of the base material and a pressure-sensitive adhesive sheet having a second pressure-sensitive adhesive layer provided on the second surface of the base material (that is, double-sided When it is in the form of an adhesive sheet with an adhesive substrate, the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer may have the same configuration or different configurations. When the configurations of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are different, the difference may be, for example, a difference in composition or a structure (thickness, surface roughness, formation range, formation pattern, etc.). For example, the second pressure-sensitive adhesive layer may be a pressure-sensitive adhesive layer that does not contain the polymer B. Further, the surface of the second pressure-sensitive adhesive layer (second pressure-sensitive adhesive surface) may have N ₈₀ / N ₅₀ of less than 5, less than 2, less than 1.5, or less than 1.

<Adhesive sheet with release liner>
The pressure-sensitive adhesive sheet disclosed herein can take the form of a pressure-sensitive adhesive product in which the surface (pressure-sensitive adhesive surface) of the pressure-sensitive adhesive layer is brought into contact with the release surface of the release liner. Therefore, this specification provides a pressure-sensitive adhesive sheet with a release liner (pressure-sensitive adhesive product) including any one of the pressure-sensitive adhesive sheets disclosed herein and a release liner having a release surface that comes into contact with the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet. obtain.

  The thickness of the release liner is not particularly limited, but is usually about 5 μm to 200 μm. When the thickness of the release liner is within the above range, it is preferable because the workability for bonding to the pressure-sensitive adhesive layer and the workability for peeling from the pressure-sensitive adhesive layer are excellent. In some embodiments, the thickness of the release liner may be, for example, 10 μm or more, 20 μm or more, 30 μm or more, or 40 μm or more. The thickness of the release liner may be, for example, 100 μm or less, or 80 μm or less from the viewpoint of facilitating peeling from the pressure-sensitive adhesive layer. The release liner may be subjected to a known antistatic treatment such as a coating type, a kneading type, or a vapor deposition type, if necessary.

  The release liner is not particularly limited. For example, a release liner having a release layer on the surface of a liner substrate such as a resin film or paper (which may be a paper laminated with a resin such as polyethylene), or a fluoropolymer. A release liner made of a resin film formed of a low-adhesive material such as (polytetrafluoroethylene or the like) or a polyolefin resin (polyethylene, polypropylene or the like) can be used. Since the surface smoothness is excellent, a release liner having a release layer on the surface of a resin film as a liner substrate or a release liner made of a resin film formed of a low adhesive material can be preferably used. The resin film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. For example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer. Examples include films, polyester films (PET films, PBT films, etc.), polyurethane films, ethylene-vinyl acetate copolymer films, and the like. For the formation of the release layer, for example, a silicone release treatment agent, a long-chain alkyl release treatment agent, an olefin release treatment agent, a fluorine release treatment agent, a fatty acid amide release treatment agent, molybdenum sulfide, silica powder, etc. A known release treating agent can be used. The use of a silicone release treatment agent is particularly preferred.

  The thickness of the release layer is not particularly limited, but is usually about 0.01 μm to 1 μm, preferably about 0.1 μm to 1 μm. The formation method of a peeling layer is not specifically limited, The well-known method according to the kind etc. of peeling processing agent to be used can be employ | adopted suitably.

<Application>
The pressure-sensitive adhesive sheet provided by this specification has a low adhesive force for a while in a temperature range from room temperature to about 50 ° C. (for example, 20 ° C. to 50 ° C.) after being bonded to an adherend. During this time, good reworkability can be exhibited, which can contribute to yield reduction and quality improvement of products including the pressure-sensitive adhesive sheet. The pressure-sensitive adhesive sheet can greatly increase the pressure-sensitive adhesive force by aging (heating to a temperature higher than 50 ° C., aging, or a combination thereof). For example, the pressure-sensitive adhesive sheet can be firmly adhered to the adherend by heating at a desired timing. Taking advantage of such features, the pressure-sensitive adhesive sheet disclosed herein is preferable in various fields for the purpose of fixing, joining, molding, decoration, protection, reinforcement, support, impact mitigation, etc. of members included in various products. Can be used.

The pressure-sensitive adhesive sheet disclosed here is affixed to an adherend in the form of a pressure-sensitive adhesive sheet with a base material in which a pressure-sensitive adhesive layer is provided on at least the first surface of a film-like base material having a first surface and a second surface. And can be preferably used as a reinforcing film for reinforcing the adherend. In such a reinforcing film, a film containing a resin film as a base film can be preferably used as the film substrate. Moreover, it is preferable that the said adhesive layer adheres to the 1st surface of a film-form base material from a viewpoint of improving reinforcement performance.
For example, in an optical member used for an optical product and an electronic member used for an electronic product, high integration, small size, light weight, and thinning are progressing, and a plurality of thin optical members having different linear expansion coefficients and thickness / Electronic members can be stacked. By adhering the reinforcing film as described above to such a member, an appropriate rigidity can be imparted to the optical member / electronic member. Thereby, in a manufacturing process and / or a product after manufacturing, curling and bending due to stress that can occur between a plurality of members having different linear expansion coefficients and thicknesses can be suppressed.
Further, in the manufacturing process of optical products / electronic products, in the aspect of performing shape processing such as cutting processing on the thin optical member / electronic member as described above, processing is performed by attaching a reinforcing film to the member and processing it. Accordingly, local stress concentration on the optical member / electronic member can be reduced, and the risk of cracks, cracks, peeling of the laminated member, and the like can be reduced. Affixing a reinforcing member to an optical member / electronic member can be used to alleviate local stress concentration during transportation, lamination, rotation, etc. of the member, or to suppress bending or bending due to the weight of the member. Can be helpful.
In addition, devices such as optical products and electronic products including the above-described reinforcing film may collide with flying objects when the devices are dropped or placed under heavy objects when used by consumers in the market. Even when unintentional stress is applied, the stress applied to the device can be alleviated by including the reinforcing film in the device. Therefore, the durability of the device can be improved by including the reinforcing film in the device.

  In addition, the pressure-sensitive adhesive sheet disclosed herein can be preferably used, for example, in a mode in which it is affixed to members constituting various portable devices (portable devices). Here, “carrying” means that it is not enough to be able to carry it alone, but means that the individual (standard adult) has a level of portability that can be carried relatively easily. To do. Examples of mobile devices here include mobile phones, smartphones, tablet computers, notebook computers, various wearable devices, digital cameras, digital video cameras, audio devices (portable music players, IC recorders, etc.), computers ( Calculators, etc.), portable game devices, electronic dictionaries, electronic notebooks, electronic books, in-vehicle information devices, portable radios, portable TVs, portable printers, portable scanners, portable modems, and other portable electronic devices, mechanical watches and pocket watches A watch, flashlight, hand mirror, etc. may be included. Examples of members constituting the portable electronic device may include optical films and display panels used in image display devices such as thin-layer displays such as liquid crystal displays and film-type displays. The pressure sensitive adhesive sheet indicated here may be preferably used also in the mode stuck on various members in a car, household appliances, etc.

The matters disclosed by this specification include the following.
(1) An adhesive sheet including an adhesive layer,
The pressure-sensitive adhesive layer includes a polymer A, a polymer B that is a copolymer of a monomer having a polyorganosiloxane skeleton and a (meth) acrylic monomer,
The polymer B has a glass transition temperature T _m1 based on the composition of the (meth) acrylic monomer of 50 ° C. or more and 100 ° C. or less,
Adhesive strength N ₈₀ after being bonded to a stainless steel plate and heated at 80 ° C. for 5 minutes is more than 5 times the adhesive strength N ₅₀ after being bonded to a stainless steel plate and held at 50 ° C. for 30 minutes. Sheet.
(2) and the adhesive strength N _50, the relationship between the adhesive force N ₂₃ after holding for 30 minutes to 23 ° C. after bonding to a stainless steel plate, the following equation:
(N ₅₀ / N ₂₃ ) <10;
The pressure-sensitive adhesive sheet according to (1), wherein
(3) The pressure-sensitive adhesive sheet according to (1) or (2), wherein the pressure-sensitive adhesive strength N ₈₀ is 10 times or more of the pressure-sensitive adhesive strength N ₂₃ after being allowed to stand at 23 ° C. for 30 minutes after being bonded to a stainless steel plate. .
(4) The above adhesive strength N ₂₃ [N / 25 mm], adhesive strength N ₅₀ [N / 25 mm] and adhesive strength N ₈₀ [N / 25 mm] are expressed by the following relational expressions:
(N ₈₀ -N ₅₀ ) / (N ₅₀ -N ₂₃ ) ≧ 2;
The pressure-sensitive adhesive sheet according to any one of (1) to (3), wherein
(5) the adhesive strength _{N 23} is less than 2.0 N / 25 mm, the adhesive sheet according to any one of the above (1) to (4).
(6) The adhesive strength _{N 50} is less than 4N / 25 mm, the adhesive sheet according to any one of the above (1) to (5).
(7) The adhesive strength _{N 80} is 15N / 25 mm or more, the pressure-sensitive adhesive sheet according to any one of the above (1) to (6).

(8) Glass transition temperature _{T A} of the polymer A is less than 0 ° C. or higher -63 ° C., the pressure-sensitive adhesive sheet according to any one of the above (1) to (7).
(9) Glass transition temperature _{T B} of the polymer B is 10 ° C. or less -10 ° C. or higher, the pressure-sensitive adhesive sheet according to any one of the above (1) to (8).
(10) The pressure-sensitive adhesive sheet according to any one of (1) to (9), wherein the polymer B has a copolymerization ratio of a monomer having a homopolymer glass transition temperature higher than 170 ° C. of 30% by weight or less.
(11) The pressure-sensitive adhesive sheet according to any one of (1) to (10), wherein the pressure-sensitive adhesive layer contains a crosslinking agent in an amount of more than 0 parts by weight and 10 parts by weight or less with respect to 100 parts by weight of the polymer A.
(12) The pressure-sensitive adhesive sheet according to any one of (1) to (11), wherein the polymer B has a weight average molecular weight of 10,000 to 50,000.
(13) The content of the polymer B in the pressure-sensitive adhesive layer is any one of the above (1) to (12), which is 0.05 to 20 parts by weight with respect to 100 parts by weight of the polymer A. Adhesive sheet.

(14) The pressure-sensitive adhesive sheet according to any one of (1) to (13), wherein the polymer A is an acrylic polymer.
(15) The pressure-sensitive adhesive sheet according to (14), wherein the monomer component for preparing the acrylic polymer includes a hydroxyl group-containing monomer.
(16) The pressure-sensitive adhesive sheet according to (14), wherein the monomer component for preparing the acrylic polymer includes an N-vinyl cyclic amide and a hydroxyl group-containing monomer.
(17) The pressure-sensitive adhesive sheet according to any one of (1) to (16), wherein the pressure-sensitive adhesive layer contains an isocyanate-based crosslinking agent.
(18) The pressure-sensitive adhesive sheet according to any one of (1) to (17), wherein the monomer component for preparing the polymer B includes methyl methacrylate (MMA).
(19) The pressure-sensitive adhesive sheet according to (18), wherein the ratio of MMA in the total amount of (meth) acrylic monomers contained in the monomer component is 55% by weight or more and 95% by weight or less.
(20) The pressure-sensitive adhesive sheet according to any one of the above (1) to (19), wherein the pressure-sensitive adhesive layer has a thickness of 3 μm to 100 μm (for example, 20 μm to 50 μm).

(21) Any of the above (1) to (20), comprising a support substrate having a first surface and a second surface, wherein the pressure-sensitive adhesive layer is laminated on at least the first surface of the support substrate. The pressure-sensitive adhesive sheet described in 1.
(22) The pressure-sensitive adhesive sheet according to (21), wherein the support substrate has a thickness of 30 μm or more.
(23) The pressure-sensitive adhesive sheet according to the above (21) or (22), wherein the thickness of the support substrate is 1.1 to 10 times the thickness of the pressure-sensitive adhesive layer.
(24) The pressure-sensitive adhesive sheet according to any one of (21) to (23), wherein the support substrate includes a resin film as a base film.
(25) The pressure-sensitive adhesive sheet according to (24), wherein the base film is a polyester film having a thickness of 35 μm or more (for example, a thickness of 35 μm or more and 500 μm or less).
(26) The pressure-sensitive adhesive sheet according to any one of (21) to (25), wherein the pressure-sensitive adhesive layer is fixed to the first surface of the support substrate.
(27) The pressure-sensitive adhesive sheet according to any one of (21) to (26), which is attached to an adherend and used for reinforcement of the adherend.
(28) The pressure-sensitive adhesive sheet according to any one of (1) to (27), wherein the surface (pressure-sensitive adhesive surface) of the pressure-sensitive adhesive layer is in contact with a peelable surface having a water contact angle of 100 degrees or more.

(29) The pressure-sensitive adhesive sheet according to any one of (1) to (28) above, and a release liner having a peelable surface in contact with the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet,
A pressure-sensitive adhesive sheet with a release liner, wherein the water contact angle of the peelable surface is 100 ° or more.
(30) The pressure-sensitive adhesive sheet with a release liner according to (29), wherein the peelable surface is a surface of a release layer formed by a silicone-based release treatment agent.

  Several examples relating to the present invention will be described below, but the present invention is not intended to be limited to the specific examples. In the following description, “parts” and “%” are based on weight unless otherwise specified.

(Preparation of polymer A1)
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube and a condenser, 60 parts of 2EHA, 15 parts of N-vinyl-2-pyrrolidone (NVP), 10 parts of methyl methacrylate (MMA), 2-hydroxyethyl 15 parts of acrylate (HEA) and 200 parts of ethyl acetate as a polymerization solvent were added and stirred at 60 ° C. under a nitrogen atmosphere for 2 hours. Then, 0.2 part of AIBN was added as a thermal polymerization initiator, and the mixture was heated at 60 ° C. for 6 hours. Reaction was performed to obtain a solution of polymer A1. The Mw of this polymer A1 was 1.1 million.

(Preparation of polymer B1)
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, a cooler, and a dropping funnel, 100 parts of toluene, 40 parts of MMA, 20 parts of n-butyl methacrylate (BMA), 20 parts of 2-ethylhexyl methacrylate (2EHMA) Polyorganosiloxane skeleton-containing methacrylate monomer having a functional group equivalent of 900 g / mol (trade name: X-22-174ASX, manufactured by Shin-Etsu Chemical Co., Ltd.) 8.7 parts, polyorganosiloxane having a functional group equivalent of 4600 g / mol 11.3 parts of a skeleton-containing methacrylate monomer (trade name: KF-2012, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.51 part of methyl thioglycolate were added as a chain transfer agent. After stirring for 1 hour at 70 ° C. in a nitrogen atmosphere, 0.2 part of AIBN was added as a thermal polymerization initiator, and after 2 hours of reaction at 70 ° C., 0.1 part by weight of AIBN was added as a thermal polymerization initiator. Then, it was reacted at 80 ° C. for 5 hours. In this way, a solution of polymer B1 was obtained. The Mw of this polymer B1 was 22000.

(Preparation of polymers B2 to B7)
The composition of the monomer components was changed as shown in Table 1, except that 0.8 parts of thioglycerol was used as the chain transfer agent and ethyl acetate was used as the polymerization solvent, the same as in the preparation of polymer B1, B7 was prepared. Mw of each polymer was 19100 for polymer B2, 19700 for polymer B3, 19600 for polymer B4, 20000 for polymer B5, 18900 for polymer B6, and 19500 for polymer B7.

Composition of the monomer components used for preparing the polymer B1 to B7, the glass transition temperature _{T m1} based on the composition of the monomer component (meth) acrylic monomer, and a glass transition temperature _{T B} of the polymer B1 to B7, Table 1 It summarizes and shows.

In addition, the weight average molecular weight of each polymer mentioned above measured on the following conditions using the GPC apparatus (the Tosoh company make, HLC-8220GPC), and calculated | required by polystyrene conversion.
[GPC conditions]
Sample concentration: 0.2 wt% (tetrahydrofuran (THF) solution)
Sample injection volume: 10 μl
-Eluent: THF-Flow rate: 0.6 ml / min
・ Measurement temperature: 40 ℃
·column:
Sample column: TSKguardcolumn SuperHZ-H (1) + TSKgel SuperHZM-H (2)
Reference column; TSKgel SuperH-RC (1 piece)
・ Detector: Differential refractometer (RI)

Also, in the calculation of _{T B} shown in Table 1, -126 ° C. as the value of Tg of the X-22-174ASX, was used -127 ° C. as the value of the KF-2012 of Tg. The Tg of these polyorganosiloxane skeleton-containing methacrylate monomers was determined by putting the monomer (measurement sample) in an aluminum simple sealed container and performing DSC (differential scanning calorimetry) under the following conditions.
[DSC condition]
Apparatus: TA Instruments, Q-2000
Temperature program: -160 ° C to 40 ° C
Temperature increase rate: 10 ° C / min
Atmospheric gas: He (50 ml / min)

<Production of adhesive sheet>
(Example 1)
In 100 parts of the polymer A1 contained in the solution, 2.5 parts of the polymer B1 and an isocyanate-based crosslinking agent (trade name: Takenate D110N, trimethylolpropane xylylene diisocyanate, manufactured by Mitsui Chemicals) Was added and mixed uniformly to prepare an adhesive composition C1.
The pressure-sensitive adhesive composition C1 was directly applied to the first surface of a 125 μm-thick polyethylene terephthalate (PET) film (trade name “Lumirror” manufactured by Toray Industries, Inc.) as a supporting substrate, dried at 110 ° C. for 2 minutes, and dried. As a result, an adhesive layer having a thickness of 25 μm was formed. The release surface of the release liner R1 was bonded to the surface (adhesive surface) of this pressure-sensitive adhesive layer. In this way, the pressure-sensitive adhesive sheet according to Example 1 was obtained in the form of a pressure-sensitive adhesive sheet with a release liner in which the pressure-sensitive adhesive surface was in contact with the release surface of the release liner.
As the release liner, MRQ25T100 manufactured by Mitsubishi Chemical Corporation (release liner having a release layer made of a silicone release treatment agent on one side of a polyester film, thickness 25 μm) was used.

(Examples 2 to 11)
Adhesive compositions C2 to C11 were prepared in the same manner as the preparation of the adhesive composition C1, except that the amounts used of the polymer B and the crosslinking agent were changed as shown in Table 2. The pressure-sensitive adhesive sheets according to Examples 2 to 11 were obtained in the same manner as the pressure-sensitive adhesive sheets according to Example 1 except that these pressure-sensitive adhesive compositions C2 to C11 were used.

<Measurement of SUS adhesive strength>
The adhesive sheet according to each example was cut into a 25 mm width together with the release liner as a test piece, an SUS plate (SUS304BA plate) cleaned with toluene as an adherend, and the adhesive strength N ₂₃ and adhesive strength N were as follows. ₅₀ and adhesive strength _N80 were measured.
(Measurement of the pressure-sensitive adhesive force _{N 23)}
In a standard environment of 23 ° C. and 50% RH, the release liner covering the adhesive surface of each test piece was peeled off, and the exposed adhesive surface was pressed against the adherend by reciprocating a 2 kg roller once. After leaving the test piece pressure-bonded to the adherend in this manner for 30 minutes in the above standard environment, using a universal tensile compression tester (device name “Tension / Compression Tester, TCM-1kNB” manufactured by Minebea) In accordance with JIS Z0237, 180 ° peeling adhesive strength (resistance to tension) was measured under the conditions of a peeling angle of 180 degrees and a tensile speed of 300 mm / min. The measurement was performed 3 times, and the average value thereof was shown in Table 2 as the adhesive strength (N ₂₃ ) [N / 25 mm] after 30 ° C. for 30 minutes.
(Measurement of adhesive strength N ₅₀ )
The test piece pressure-bonded to the adherend in the same manner as the measurement of the adhesive strength ₂₃ is kept in an environment of 50 ° C. for 30 minutes, and then left in the standard environment for 30 minutes, and then peeled off by 180 ° in the same manner. Was measured. The measurement was performed three times, and the average value was shown in Table 2 as the adhesive strength (N ₅₀ ) [N / 25 mm] after 30 minutes at 50 ° C.
(Measurement of the pressure-sensitive adhesive force _{N 80)}
The test piece pressure-bonded to the adherend in the same manner as in the measurement of the adhesive strength ₂₃ was heated at 80 ° C. for 5 minutes, and then allowed to stand for 30 minutes in the standard environment. did. The measurement was performed three times, and the average value was shown in Table 2 as the adhesive strength (N ₈₀ ) [N / 25 mm] after 5 minutes at 80 ° C. The adhesive sheets of Examples 1 to 11 are all, it was confirmed not to cause the anchor failure when measuring the adhesive strength N _80.
Based on these adhesion _{measurements, N 80 / N 50, N} 50 / N 23, N 80 / N 23, N 50 -N 23 _{and, (N 80 -N 50) /} (N 50 -N 23) Was calculated. The obtained results are shown in Table 2.

As shown in Table 2, the pressure-sensitive adhesive sheet of Example 5-9 in which the glass transition temperature _{T m1} was used polymer B3~B5 in the range of 50 ° C. to 100 ° _C., it N 80 _{/ N 50} is 5 or more Thus, it was confirmed that even when a temperature of about 50 ° C. was applied at the initial stage of application, low adhesiveness suitable for reworking was maintained, and that the adhesive strength could be greatly increased by heating at 80 ° C. for 5 minutes.

On the other hand, the adhesive sheets of Examples 1 to 4 and Example 11 using polymers B1, B2, and B7 having a glass transition temperature T _m1 lower than 50 ° C. have N ₈₀ / N ₅₀ of less than 5, and about 50 ° C. at the initial stage of application. The adhesive strength was likely to increase with the addition of the temperature. In the pressure-sensitive adhesive sheet of Example 4, N ₅₀ was relatively low, but the pressure-sensitive adhesive force could not be increased greatly by heating at 80 ° C. for 5 minutes. Further, in Example 10 using the polymer B6 having a glass transition temperature T _m1 exceeding 100 ° C., the adhesive strength could not be increased by heating at 80 ° C. for 5 minutes.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

1, 2, 3 Adhesive sheet 10 Support base material 10A First surface 10B Second surface 21 Adhesive layer (first adhesive layer)
21A Adhesive surface (first adhesive surface)
21B Adhesive surface (second adhesive surface)
22 Adhesive layer (second adhesive layer)
22A adhesive surface (second adhesive surface)
31, 32 Release liner 100, 200, 300 Adhesive sheet with release liner (adhesive product)

Claims (9)

An adhesive sheet including an adhesive layer,
The pressure-sensitive adhesive layer includes a polymer A, a polymer B that is a copolymer of a monomer having a polyorganosiloxane skeleton and a (meth) acrylic monomer,
The polymer A is an acrylic polymer,
Glass transition temperature _{T A} of the polymer A is less than 0 ° C. -55 ° C. or higher,
The monomer component for preparing the polymer A includes an N-vinyl cyclic amide and a hydroxyl group-containing monomer,
The polymer B has a glass transition temperature T _m1 based on the composition of the (meth) acrylic monomer of 50 ° C. or more and 100 ° C. or less,
The polymer B has a copolymerization ratio of a monomer having a homopolymer glass transition temperature higher than 170 ° C. of 30% by weight or less,
Adhesive strength N ₈₀ after being bonded to a stainless steel plate and heated at 80 ° C. for 5 minutes is more than 5 times the adhesive strength N ₅₀ after being bonded to a stainless steel plate and held at 50 ° C. for 30 minutes. Sheet. Wherein the adhesive strength N _50, the relationship between the adhesive force N ₂₃ after leaving for 30 minutes at 23 ° C. after bonding to a stainless steel plate, the following equation:
(N ₅₀ / N ₂₃ ) <10;
The pressure-sensitive adhesive sheet according to claim 1, wherein The polymer glass transition temperature T _A of A is less than -50 ° C. or higher -10 ° C., the pressure-sensitive adhesive sheet according to claim 1 or 2. The glass transition temperature T _B of the polymer B is -10 ° C. or higher 10 ° C. or less, the pressure-sensitive adhesive sheet according to any one of claims 1 to 3. The pressure-sensitive adhesive layer according to any one of claims 1 to 4 , wherein the pressure-sensitive adhesive layer contains a crosslinking agent in an amount of more than 0 parts by weight and 10 parts by weight or less with respect to 100 parts by weight of the polymer A. The pressure-sensitive adhesive sheet according to any one of claims 1 to 5 , wherein the polymer B has a weight average molecular weight of 10,000 to 50,000. The pressure-sensitive adhesive sheet according to any one of claims 1 to 6 , wherein the content of the polymer B in the pressure-sensitive adhesive layer is 0.05 part by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the polymer A. The pressure-sensitive adhesive according to any one of claims 1 to 7 , further comprising a support substrate having a first surface and a second surface, wherein the pressure-sensitive adhesive layer is laminated on at least the first surface of the support substrate. Sheet. The pressure sensitive adhesive sheet according to claim 8 whose thickness of said support substrate is 30 micrometers or more.

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