JP2019094385A - Adhesive sheet - Google Patents

Abstract

To provide an adhesive sheet capable of maintaining reworkability even if a temperature of approximately 50°C is applied at the early stage of adhesion to an adherend and thereafter capable of significantly increasing the adhesion force.SOLUTION: There is provided an adhesive sheet containing an adhesive layer. The adhesive layer contains a polymer A and a polymer B which is a copolymer of a monomer having a polyorganosiloxane skeleton and a (meth)acrylic monomer. The polymer B has a glass transition temperature Tof 50°C or more and 100°C or less based on the composition of the (meth)acrylic monomer. An adhesive force Nof the adhesive sheet after heating at 80°C for 5 minutes after adhesion is 5 times or more an adhesive force Nafter left at 50°C for 30 minutes after adhesion.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an adhesive sheet.

  The pressure-sensitive adhesive sheet is used for the purpose of adhesion between adherends, fixing of articles to the adherend, reinforcement of the adherend, and the like by firmly adhering to the adherend. Conventionally, for such purpose, a pressure-sensitive adhesive sheet has been used which exhibits high adhesive strength from the early stage of bonding. Moreover, recently, as in Patent Documents 1 to 3, there has been proposed a pressure-sensitive adhesive sheet which exhibits low adhesive strength at the initial stage of application to an adherend, and thereafter can greatly increase the adhesive strength. According to the pressure-sensitive adhesive sheet having such a characteristic, before the rise of the adhesive strength, the adhesive sheet exhibits re-sticking property (rework property) useful for suppressing the yield decrease due to the sticking mistake or the sticking failure of the pressure-sensitive adhesive sheet. After rising, it can exhibit strong tackiness suitable for the intended purpose of use of the pressure-sensitive adhesive sheet.

JP, 2014-224227, A Patent No. 5890596 Patent No. 5951153 gazette

  By the way, depending on the mode of use of the adhesive sheet, there may be a request for rework due to the finding of sticking errors or sticking failure, occurrence of positional deviation due to the influence of the subsequent process, etc. after proceeding to the subsequent process after pasting. obtain. In such a case, for example, in a period in which reworkability is required of the adhesive sheet attached to the adherend, for example, accompanying the operation of an apparatus (a conveying apparatus, an inspection apparatus, other various processing apparatuses, etc.) used in a manufacturing process. A temperature of about 40 ° C. to 50 ° C. may be added to the pressure-sensitive adhesive sheet due to an accidental factor such as the influence of heat generation, exhaust heat from an adjacent device, temperature rise of the manufacturing environment, and the like. Therefore, an object of the present invention is to provide a pressure-sensitive adhesive sheet capable of maintaining reworkability even if a temperature of about 50 ° C. is added at the initial stage of application to an adherend and thereafter greatly increasing the adhesive strength. .

According to this specification, a pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer is provided. The pressure-sensitive adhesive layer contains a polymer A, and a polymer B which 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 of 50 ° C. or more and 100 ° C. or less based on the composition of the (meth) acrylic monomer. The adhesive sheet, the adhesive strength N ₈₀ after heating for 5 minutes at 80 ° C. after bonding to a stainless steel plate, 5 times the adhesive strength N ₅₀ after holding for 30 minutes to 50 ° C. after bonding to a stainless steel plate It is above.

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 or more (ie, N ₈₀ / N ₅₀ 55). As a result, even in a usage mode in which a temperature of about 50 ° C. can be added to the initial stage of application, good reworkability can be exhibited, and adhesion can be greatly increased by subsequent heating or the like.

PSA sheet according to some aspects, the aforementioned adhesive force N _50, the relationship between the adhesive force N ₂₃ after leaving at 23 ° C. 30 minutes after bonding to a stainless steel plate, the following equation: (N 50 _/ N ₂₃ ) <10; With such a pressure-sensitive adhesive sheet, the difference in adhesion (and reworkability) between the case of being maintained at room temperature and the case of being exposed to temperatures up to about 50 ° C. is small at the initial stage of bonding, so workability and process control From the viewpoint of easiness of

In some embodiments, the glass transition temperature TA of the polymer _A may be, for example, -80 ° C or more and less 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 may be, for example, -10 ° C or more and 10 ° C or less. 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 30% by weight or less of monomers whose homopolymer has a glass transition temperature of more than 170 ° C. The pressure-sensitive adhesive sheet disclosed herein can be suitably carried out using the polymer B of such a copolymer composition.

  In some embodiments, the pressure-sensitive adhesive layer may contain more than 0 parts by weight and 10 parts by weight or less of a crosslinking agent based on 100 parts by weight of the polymer A. By using a crosslinking agent, the adhesive strength at the initial stage of application can be effectively controlled in a temperature range up to about 50 ° C. As a result, it tends to be easy to obtain a pressure-sensitive adhesive sheet in which the reworkability in the initial stage of bonding and the strong tackiness after the increase in tackiness are suitably achieved.

  In some embodiments, as the polymer B, one having a weight average molecular weight (Mw) of 10000 or more and 50000 or less can be preferably used. According to the polymer B having Mw in the above range, the adhesive strength at the initial stage of application is low, and a pressure-sensitive adhesive sheet having high adhesive strength after heating can be easily obtained.

  In some embodiments, the content of the polymer B in the pressure-sensitive adhesive layer can be in the range of 0.05 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the polymer A. According to content of the said range, the adhesive force of the adhesion | pasting initial stage is low, and the adhesive sheet with high adhesive force after a heating is easy to be obtained.

  The pressure-sensitive adhesive sheet disclosed herein comprises a supporting 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 supporting substrate, that is, with a substrate It can be implemented in the form of an adhesive sheet. Such a substrate-attached pressure-sensitive adhesive sheet can be good in handleability and processability. As said support base material, a thing with a thickness of 30 micrometers or more can be employ | adopted preferably, for example.

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

BRIEF DESCRIPTION OF THE DRAWINGS 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 the matters specifically mentioned in the present specification and necessary for the practice of the present invention are based on the teaching of the practice of the invention described in the present specification and the common general knowledge at the time of filing. It can be understood by the vendor. The present invention can be implemented based on the contents disclosed in the present specification and common technical knowledge in the field.
In the following drawings, the same reference numerals may be given to members / parts having the same function, and overlapping 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 the sizes and scales of products actually provided are not necessarily accurately represented.

  Moreover, in this specification, the term "acrylic polymer" refers to a polymer containing monomer units derived from (meth) acrylic monomers in the polymer structure, and is typically a monomer derived from (meth) acrylic monomers A polymer containing more than 50% by weight of units. Further, the (meth) acrylic monomer refers to a monomer having at least one (meth) acryloyl group in one molecule. Here, "(meth) acryloyl group" is a meaning which generally points out an acryloyl group and a methacryloyl group. Therefore, the concept of the (meth) acrylic monomer referred to herein may include both a monomer having an acryloyl group (acrylic monomer) and a monomer having a methacryloyl group (methacrylic monomer). Similarly, in the present specification, “(meth) acrylic acid” means acrylic acid and methacrylic acid, and “(meth) acrylate” generally means acrylate and methacrylate, respectively.

<Example of structure of adhesive sheet>
The pressure-sensitive adhesive sheet disclosed herein is configured to include a pressure-sensitive adhesive layer. The pressure-sensitive adhesive sheet disclosed herein may be in the form of a substrate-attached pressure-sensitive adhesive sheet in which the above-mentioned pressure-sensitive adhesive layer is laminated on one side or both sides of a supporting substrate. It may be in the form. Hereinafter, the support substrate may be simply referred to as "substrate".

  The structure of the pressure-sensitive adhesive sheet according to one embodiment is schematically shown in FIG. The pressure-sensitive adhesive sheet 1 is a single-sided pressure-sensitive adhesive sheet with a substrate including a sheet-like support substrate 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 10A side of the support substrate 10. The pressure-sensitive adhesive sheet 1 is used by sticking 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) is releasable from the surface (pressure-sensitive adhesive surface) 21A of the pressure-sensitive adhesive layer 21 at least on the side facing the pressure-sensitive adhesive layer 21. It may be a component of the release liner-attached pressure-sensitive adhesive sheet 100 in a form in which the release liner 31 is in contact with the surface (release surface). As the release liner 31, for example, a release liner made of a release treatment agent may be provided on one side of a sheet-like base material (liner base material), and it is preferable to use one configured such that the one side becomes a release side. Alternatively, using the support base 10 in which the release liner 31 is omitted and the second surface 10B is the release surface, the adhesive surface 21A is formed on the second surface 10B of the support base 10 by winding the adhesive sheet 1. It may be in a form of contact (roll form). When the pressure-sensitive adhesive sheet 1 is attached to an adherend, the release liner 31 or the second surface 10B of the support substrate 10 is peeled off from the 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 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. The pressure-sensitive adhesive layer 22 is configured as a double-sided pressure-sensitive adhesive sheet with a substrate. The pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer) 21 is fixed to the first surface 10A of the support substrate 10, and the pressure-sensitive adhesive layer (second pressure-sensitive adhesive layer) 22 is fixed to the second surface 10B of the support substrate 10. There is. The pressure-sensitive adhesive sheet 2 is used by sticking the pressure-sensitive adhesive layers 21 and 22 to different parts of the adherend. The places where the pressure-sensitive adhesive layers 21 and 22 are attached may be places of different members, or may be different places in a single member. The adhesive sheet 2 before use is, as shown in FIG. 2, a surface (first adhesive surface) 21A of the adhesive layer 21 and a surface (second adhesive surface) 22A of the adhesive layer 22 at least the adhesive layer 21, It can be a component of the release liner-attached pressure-sensitive adhesive sheet 200 in a form in which the side opposite to 22 is in contact with the release liners 31 and 32 which are respectively release surfaces. As the release liners 31 and 32, for example, a release liner made of a release treatment agent is preferably provided on one side of a sheet-like base material (liner base material) so that the one side becomes a release surface. obtain. Alternatively, the release liner 32 may be omitted, and the second adhesive surface 22A may be release liner 31 by using the release liner 31 having release surfaces on both sides and overlapping it with the adhesive sheet 2 and winding it in a spiral. A release liner-attached pressure-sensitive adhesive sheet may be configured in a form (roll form) in contact with the back surface of the sheet.

  The structure of the pressure-sensitive adhesive sheet according to still another embodiment is schematically shown in FIG. The pressure-sensitive adhesive sheet 3 is configured as a substrate-less double-sided pressure-sensitive adhesive sheet formed of a pressure-sensitive adhesive layer 21. The adhesive sheet 3 has a first adhesive surface 21A constituted by one surface (first surface) of the adhesive layer 21 and a second adhesive surface constituted by the other surface (second surface) of the adhesive layer 21. 21B is used by being attached to a different part of the adherend. The pressure-sensitive adhesive sheet 3 before use is, as shown in FIG. 3, release liners 31 and 32 in which the first pressure-sensitive adhesive surface 21A and the second pressure-sensitive adhesive surface 21B are at least peeling away from the pressure-sensitive adhesive layer 21. It can be a component of the release liner-attached pressure-sensitive adhesive sheet 300 in the form of being in contact with Alternatively, the release liner 32 may be omitted, and the second adhesive surface 21 B may be release liner 31 by using the release liner 31 having release surfaces on both sides and superposing the release liner 31 on the adhesive sheet 3 in a spiral shape. A release liner-attached pressure-sensitive adhesive sheet may be configured in a form (roll form) in contact with the back surface of the sheet.

  In addition, what is called an adhesive tape, an adhesive film, an adhesive label, etc. may be included in the concept of the adhesive sheet here. The pressure-sensitive adhesive sheet may be in the form of a roll, or may be in the form of a single sheet, or may be cut or punched into an appropriate shape according to the use or the mode of use. The pressure-sensitive adhesive layer in the art disclosed herein is typically formed continuously, but is not limited thereto, and may be formed, for example, in a regular or random pattern such as dot-like or stripe-like. Good.

<Pressure-sensitive adhesive layer>
The pressure-sensitive adhesive sheet disclosed herein includes a pressure-sensitive adhesive layer including a polymer A, and a polymer B which is a copolymer of a monomer having a polyorganosiloxane skeleton and a (meth) acrylic monomer. Such an adhesive layer may be formed from an 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 water dispersion type, solvent type, hot melt type, active energy ray curable type (for example, photocurable type).

(Polymer A)
As the polymer A, acrylic polymers, rubber polymers, polyester polymers, urethane polymers, polyether polymers, silicone polymers, polyamide polymers, fluorine polymers, etc. known in the field of pressure-sensitive adhesives in the room temperature range One or more 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, wherein T _A is less than 0 ° C., may be preferably employed. A pressure-sensitive adhesive containing such polymer A exhibits appropriate fluidity (for example, the mobility of the polymer chain contained in the pressure-sensitive adhesive), and thus combines the initial low tackiness and the strong tackiness after heating. Suitable for the realization of adhesive sheets. 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 or 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 in N ₅₀ , in some embodiments, T _A may be, for example, −63 ° C. or higher, −55 ° C. or higher, −50 ° C. or higher, or −45 ° C. or higher. .

Here, in this specification, the glass transition temperature (Tg) of a polymer is a nominal value described in the literature, a catalog or the like, or according to the Fox equation based on the composition of monomer components used for preparation of the polymer It means the required Tg. The Fox equation, as shown below, is a relationship between the Tg of the copolymer and the glass transition temperature Tgi of a homopolymer obtained by homopolymerizing each of the monomers constituting the copolymer.
1 / Tg = Σ (Wi / Tgi)
In the above Fox equation, Tg is the glass transition temperature of the copolymer (unit: K), Wi is the weight fraction of monomer i in the copolymer (copolymerization ratio by weight), Tgi is a homopolymer of monomer i Represents the glass transition temperature (unit: K) of When the target polymer of the Tg specification is a homopolymer, the Tg of the homopolymer matches the Tg of the target polymer.

  As a glass transition temperature of the homopolymer used for calculation of Tg, the value as described in a well-known data shall be used. Specifically, numerical values are given in “Polymer Handbook” (Third Edition, John Wiley & Sons, Inc., 1989). The highest value is adopted about the monomer in which a plurality of types of values are described in the above-mentioned Polymer Handbook.

As a glass transition temperature of a homopolymer of a monomer which is not described in the above-mentioned Polymer Handbook, values obtained by the following measuring method are used except for the monomer having a polyorganosiloxane skeleton.
Specifically, 100 parts by weight of a monomer, 0.2 parts by weight of 2,2'-azobisisobutyronitrile and acetic acid as a polymerization solvent in a reactor equipped with a thermometer, a stirrer, a nitrogen introducing pipe and a reflux condenser 200 parts by weight of ethyl is charged and stirred for 1 hour while flowing nitrogen gas. After oxygen in the polymerization system is removed in this manner, the temperature is raised to 63 ° C. and reaction is carried out for 10 hours. Then, it is cooled to room temperature to obtain a homopolymer solution having a solid concentration of 33% by weight. The homopolymer solution is then cast coated on a release liner and dried to make a test sample (sheet-like homopolymer) about 2 mm thick. This test sample is punched out into a disk shape of 7.9 mm in diameter, sandwiched by parallel plates, and shear strain at a frequency of 1 Hz using a visco-elasticity tester (manufactured by TA Instruments Japan, model name "ARES") The visco-elasticity is measured by a shear mode at a temperature rising rate of -70 ° C. to 150 ° C. and a temperature rising rate of 5 ° C./min, and the temperature corresponding to the peak top temperature of tan δ is taken as the Tg of the homopolymer.

  Further, as for a monomer having a polyorganosiloxane skeleton, a value obtained by performing DSC (differential scanning calorimetry) for the monomer, more specifically, a value obtained according to the method described in the examples described later The equation of Fox 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 the polymer A of such Mw, it is easy to obtain a pressure-sensitive adhesive having good cohesion. In some embodiments, the Mw of the polymer A may be, for example, 10 × 10 ⁴ or more, 20 × 10 ⁴ or more, or 30 × 10 ⁴ or more. In addition, it is appropriate that the Mw of the polymer A is usually about 500 × 10 ⁴ or less. Such a polymer of Mw is suitable for realizing a pressure-sensitive adhesive sheet having a low adhesive strength at the initial stage of application and a high adhesive strength after heating since it is easy to form a pressure-sensitive adhesive exhibiting appropriate fluidity (motility of polymer chains). ing.

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

  An acrylic polymer can be preferably employed as the polymer A in the pressure-sensitive adhesive sheet disclosed herein. When an acrylic polymer is used as the polymer A, good compatibility with the polymer B tends to be easily obtained. The good compatibility between the polymer A and the polymer B is preferable because it can contribute to the reduction of the initial tack and the improvement of the tack 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 a monomer unit 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 ) It may be a polymer which is an acrylic acid alkyl ester. 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. The proportion of (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, 70% by weight or more because of easy balance of properties. May be. For the same reason, the proportion of (meth) acrylic acid C _1-20 alkyl ester in the total amount of 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 (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 (meth) acrylic acid C _1-20 alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate ( (Meth) acrylate n-butyl, (meth) acrylate isobutyl, (meth) acrylate s-butyl, (meth) acrylate t-butyl, 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, (meth) acrylate isodecyl, (meth) acrylate undecyl, (meta ) Dodecyl acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, stearyl (meth) acrylate, (meth) Isostearyl acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate and the like can be mentioned.

Among these, it is preferable to use at least (meth) acrylic acid C _1-18 alkyl ester, and it is more preferable to use at least (meth) acrylic acid C _1-14 alkyl ester. 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) May be contained as monomer units. For example, acrylic polymers comprising one or both of n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA) are preferred, and acrylic polymers comprising at least 2EHA are 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 constituting the acrylic polymer together with the (meth) acrylic acid alkyl ester as the main component, if necessary, another monomer (copolymerizable monomer) copolymerizable with the (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 enhance the cohesion of the acrylic polymer. The copolymerizable monomers can be used alone or in combination of two or more.

As non-limiting specific examples of copolymerizable monomers, the following may be mentioned.
Carboxy group-containing monomers: 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.
Hydroxy group-containing monomer: for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, (meth) acrylic 4-hydroxybutyl acid, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxy lauryl (meth) acrylate, (4-hydroxy acrylate (Meth) hydroxyalkyl (meth) acrylates such as methyl (cyclohexyl) methyl (meth) acrylate and the like.
Monomers containing sulfonic acid group or phosphoric acid group: for example, styrene sulfonic acid, allyl sulfonic acid, sodium vinyl sulfonic acid, 2- (meth) acrylamido-2-methylpropane sulfonic acid, (meth) acrylamidopropane sulfonic acid, sulfo Propyl (meth) acrylate, (meth) acryloyloxy naphthalene sulfonic acid, 2-hydroxyethyl acryloyl phosphate and the like.
Epoxy group-containing monomers: for example, epoxy group-containing acrylates such as glycidyl (meth) acrylate and 2-ethyl glycidyl ether (meth) acrylate, allyl glycidyl ether, glycidyl ether (meth) acrylate and the like.
Cyano group-containing monomer: for example, acrylonitrile, methacrylonitrile and the like.
Isocyanate group-containing monomer: for example, 2-isocyanatoethyl (meth) acrylate and the like.
Amide group-containing monomers: 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, etc .; N-ethyl (meth) N-alkyl (meth) acrylamides such as acrylamide, N-isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, N-n-butyl (meth) acrylamide and the like; N-vinylcarboxylic acid amides such as N-vinylacetamide and the like A monomer having a hydroxyl group and an amide group, for example, N- (2-hydro) Syethyl) (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 Monomers having a group such as N-alkoxyalkyl (meth) acrylamides such as N-methoxymethyl (meth) acrylamide, N-methoxyethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, etc .; N-dimethylaminopropyl (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-morpholindione, N-vinylpyrazole, N-vinylisoxazole, N-vinyl Thiazole, N-vinylisothiazole, N-vinyl pyridazine (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-cyclohexyl maleimide, N-isopropyl maleimide, N-lauryl maleimide, N-phenyl maleimide and the like.
Itaconimides: for example, N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylconacimide, N-cyclohexylitaconimide, N-lauryl Itacon imide etc.
Aminoalkyl (meth) acrylates: for example, aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, (meth) acrylate t -Butylaminoethyl.
Alkoxy group-containing monomers: for example, 2-methoxyethyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, (meth) acrylate (Meth) acrylic acid alkoxyalkyls such as butoxyethyl and (meth) acrylic acid ethoxypropyl; (meth) acrylic acid methoxyalkylene glycol (meth) acrylic acid methoxyethylene glycol and (meth) acrylic acid methoxypolypropylene glycol and the like 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 compounds: For example, styrene, α-methylstyrene, vinyl toluene and the like.
Olefins: For example, ethylene, butadiene, isoprene, isobutylene etc.
(Meth) acrylic esters 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 atoms (meth) acrylates such as vinyl chloride and fluorine atoms (meth) acrylates, silicon atoms such as silicone (meth) acrylates (Meth) acrylates, (meth) acrylic esters obtained from terpene compound derivative alcohols, etc.

  When such a copolymerizable monomer is used, the amount thereof to be used is not particularly limited, but usually, it is suitable to be 0.01% by weight or more of the total amount of monomer components. The amount of the copolymerizable monomer used may be 0.1% by weight or more, or 1% by weight or more of the total amount of the monomer components, from the viewpoint of exhibiting the effects of the use of the copolymerizable monomer better. The amount of the copolymerizable monomer used can be 50% by weight or less of the total amount of the monomer components, and is preferably 40% by weight or less. Thereby, the cohesive force of the pressure-sensitive adhesive can be prevented from becoming too high, and the tackiness at normal temperature (25 ° C.) can be improved.

  In some embodiments, the acrylic polymer comprises, 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 And 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 above general formula (M1) is a divalent organic group.

  By using N-vinyl cyclic amide, the cohesion and polarity of the pressure-sensitive adhesive can be adjusted to improve adhesion after heating. Specific examples of 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-morpholindione, etc. may be mentioned. 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 generally 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 an 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 above monomer components. In addition, from the viewpoint of improving tackiness at normal temperature (25 ° C.) and flexibility at low temperature, the amount of N-vinyl cyclic amide used is usually 40% by weight or less of the total amount of the above monomer components. , 30 wt% or less, or 20 wt% or less.

  By using a hydroxyl group-containing monomer, the cohesion and polarity of the pressure-sensitive adhesive can be adjusted to improve the adhesion after heating. In addition, the hydroxyl group-containing monomer can provide a reaction point with a crosslinking agent (for example, an isocyanate-based crosslinking agent) described later, and can enhance the cohesion of the adhesive by the crosslinking reaction.

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

  The amount of the hydroxyl group-containing monomer to be used is not particularly limited, but 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 It is appropriate to use 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 normal temperature (25 ° C.) and improving flexibility at low temperature, the amount of the hydroxyl group-containing monomer used is usually 40% by weight or less of the total amount of the above monomer components. The content may be less than or equal to 20% by weight, or less than or equal to 10% by weight, or less than or equal to 5% by weight.

  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 of the total amount of monomer components for preparing the acrylic polymer. 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. In addition, the total amount of the N-vinyl cyclic amide and the hydroxyl group-containing monomer can be, for example, 50% by weight or less of the total amount of monomer components, and preferably 40% by weight or less.

  The method for obtaining an acrylic polymer is not particularly limited, and various polymerization methods known as synthetic methods for acrylic polymers, such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, photopolymerization, etc. Can be adopted as appropriate. In some embodiments, solution polymerization methods may be preferably employed. The polymerization temperature when performing solution polymerization can be appropriately selected according to the type of monomer and solvent used, the type of polymerization initiator, etc., and for example, it is 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, photo polymerization initiators and the like according to the polymerization method. The polymerization initiators can be used alone or in combination of two or more.

  As a thermal polymerization initiator, for example, an azo polymerization initiator (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 and the like); persulfates such as potassium persulfate; peroxide type polymerization initiators (eg, dibenzoyl peroxide, t-butyl per Reeto, lauroyl peroxide, etc.); redox polymerization initiators, and the like. The use amount of the thermal polymerization initiator is not particularly limited, but, for example, 0.01 to 5 parts by weight, preferably 0.05 to 5 parts by weight with respect to 100 parts by weight of the monomer component used for preparation of the acrylic polymer. The amount may 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 based photoinitiator, benzoin based photoinitiator, benzyl based photoinitiator, benzophenone based photoinitiator, ketal based photoinitiator, thioxanthone based photoinitiator, acyl phosphine oxide based photopolymerization initiation An agent etc. can be used. The use amount of the photopolymerization initiator is not particularly limited, but, for example, 0.01 part by weight to 5 parts by weight, preferably 0.05 parts by weight to 100 parts by weight of the monomer component used for preparation of the acrylic polymer The amount may be in the range of 3 parts by weight.

  In some embodiments, the acrylic polymer is a partially polymerized product in which a portion of the monomer component is polymerized by irradiating ultraviolet light (UV) to a mixture in which a polymerization initiator is blended with the monomer component as described above (acrylic In the form of polymer syrup, it can be included in the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer. A pressure-sensitive adhesive composition containing such an acrylic polymer syrup can be applied to a predetermined object and irradiated with ultraviolet light to complete the polymerization. That is, the said acrylic polymer syrup can be grasped | ascertained as a precursor of an acrylic polymer. The pressure-sensitive adhesive layer disclosed herein can be formed, for example, using a pressure-sensitive adhesive composition containing the above-mentioned acrylic polymer syrup and polymer B.

(Polymer B)
The polymer B in the art 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 adhesion 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 adheres to it by heating to a temperature higher than 50 ° C. or aging. It can function as an adhesion rise retarder that increases adhesion to the body. The monomer S1 is not particularly limited, and any monomer containing a polyorganosiloxane skeleton can be used. Monomer S1 promotes uneven distribution of polymer B on the surface of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet before use (before bonding to the adherend) due to the low polarity derived from its structure, and light peeling at the initial stage of bonding Develop sex (low tackiness). As the monomer S1, one having a structure having a polymerizable reactive group at one end can be preferably used. By 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 low initial tack and high tack after heating due to the mobility and mobility of the side chain.

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 one end reactive silicone oil made by Shin-Etsu Chemical Co., Ltd. The monomers S1 can be used alone or in combination of two or more.

Here, R ³ in the above 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 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 monomer S1 is less than 700 g / mol, the initial tack may not be sufficiently suppressed. When the functional group equivalent of the monomer S1 is 15000 g / mol or more, the increase in adhesion may be insufficient. When the functional group equivalent of the monomer S1 is in the above range, the compatibility (for example, the compatibility with the polymer A) and the mobility in the pressure-sensitive adhesive layer can be easily adjusted to an appropriate range, and the initial low tackiness It becomes easy to implement | achieve the adhesive sheet which makes compatible with the strong adhesiveness after an adhesive force rise by a high level.

Here, "functional group equivalent" means the weight of the main skeleton (for example, polydimethylsiloxane) bonded to one functional group. The title unit g / mol is converted to 1 mol of functional group. The functional group equivalent of monomer S1 can be calculated, for example, from the spectral intensity of ¹ H-NMR (proton NMR) based on nuclear magnetic resonance (NMR). Calculating functional group equivalent of the monomer S1, based on the spectral intensity of ^{1 H-NMR (g / mol} ) ^is, 1 H-NMR based on general structure analysis method according to the spectral analysis, Japanese Patent No. 5951153, if necessary It can carry out with reference to the description of the publication.

When two or more kinds of monomers having different functional group equivalents are used as the monomer S1, an arithmetic average value can be used as the functional group equivalent of the monomer S1. That is, the functional group equivalent of monomer S1 consisting of n types of monomers (monomer S1 ₁ , monomer S1 ₂ ... Monomer S1 _n ) having different functional group equivalents 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 of the amount of the functional group equivalent × monomer S1 _n) / (monomer S1 ₁ of the amount + monomer S1 ₂ of the amount + ... + amount of monomer S1 _n)

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

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

In the polymer B in the art disclosed herein, the composition of the (meth) acrylic monomer contained in the above monomer component is such that the glass transition temperature T _m1 based on the composition of the (meth) acrylic monomer is 50 ° C. or more and 100 ° C. or less It is preferable to set so that Polymer B having a T _m1 of 50 ° C. or more tends to suppress the increase in N _{50 in} the pressure-sensitive adhesive sheet containing the polymer B. This is because, according to polymer B having a T _m1 of 50 ° C. or more, the polymer B contains an improvement in the mobility and mobility of the polyorganosiloxane structural part as the temperature rises from room temperature to about 50 ° C. (meth) It is considered to be effectively suppressed by the monomer unit derived from the acrylic monomer, and to better maintain low tackiness due to the presence of the polyorganosiloxane structural portion. When T _m1 falls below 50 ° C., the effect of suppressing the rise in N ₅₀ decreases. When T _m1 is higher than 100 ° C., the adhesion after heating (N ₈₀ ) tends to decrease. According to polymer B in which T _m1 is 50 ° C. or more and 100 ° C. or less, N ₈₀ can be greatly increased relative to N ₅₀ . Therefore, polymer B having a composition in which T _m1 is in the above range is suitable for the realization of a pressure-sensitive adhesive sheet satisfying N ₈₀ / N ₅₀ 55.

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 It may be 70 ° C. or more. With polymer B with a higher T _{m1, the} effect of suppressing the rise in N ₅₀ tends to be greater. In addition, from the viewpoint of facilitating the increase in adhesion by heating to a temperature range higher than 50 ° C., in some embodiments, T _m1 may be, for example, 100 ° C. or less, or 90 ° C. or less, 85 ° C. The temperature may be lower than or equal to 80 ° C. or lower than 80 ° C.

Here, the glass transition temperature T _m1 based on the composition of the (meth) acrylic monomer is 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. It means the required Tg. For T _m1 , the above-mentioned Fox's formula is applied to only (meth) acrylic monomers among monomer components used for preparation of polymer B, and the glass transition temperature of the homopolymer of each (meth) acrylic monomer and 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 facilitating the effect of appropriately setting T _m1 , 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 can be, for example, be less than 50 ° C. may be at 30 ° C. or less, may be at 20 ° C. or less, may be at 15 ℃ below, may be 10 ° C. or less. When T _B of the polymer B is lower, better mobility of the polymer B, tends to easily increase the adhesion by heating at 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 _increases, tend to be easily suppressed _{N 50.}

In some embodiments of the pressure-sensitive adhesive sheet disclosed herein, the polymer B preferably has a copolymerization ratio of 30% by weight or less of a monomer whose homopolymer has a glass transition temperature higher than 170 ° C. Here, in the present specification, the copolymerization ratio of the monomer is 0% by weight, that is, the copolymerization ratio of the monomer is substantially copolymerized, unless otherwise specified. Concept that does not include the Further, “not substantially copolymerized” means that the above-mentioned monomers are not copolymerized at least intentionally. When the copolymerization ratio of monomers having a glass transition temperature of homopolymers higher than 170 ° C. is high, mobility of polymer B tends to be insufficient, and it is difficult to increase adhesion by heating to a temperature range higher than 50 ° C. It 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 controlling the mobility of the polymer B is likely to be suitably exhibited by the composition of the (meth) acrylic monomer contained in the monomer component. T _m1 -T _B may be, for example, about 40 ° C. to 100 ° C., may be about 50 ° C. to 90 ° C., or 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, 50 ° C. to 130 ° C., and may be about 60 ° C. to 120 ° C. or about 70 ° C. to 120 ° C.

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

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

  The amount of the (meth) acrylic acid alkyl ester and the alicyclic hydrocarbon group-containing (meth) acrylic acid ester used is, for example, 10% by weight or more and 95% by weight with respect to all the monomer components for preparing the polymer B %, May be 20% by weight to 95% by weight, may be 30% by weight to 90% by weight, and may be 40% by weight to 90% by weight, 50 % By weight or more and 85% by weight or less. The use of (meth) acrylic acid alkyl esters may be advantageous in view of the ease of raising the tack upon heating to temperatures above 50 ° C. In some embodiments, the amount used of the (meth) acrylic acid ester having an alicyclic hydrocarbon group is 50% by weight of the total amount of (meth) acrylic monomers contained in the monomer component for preparing the polymer B It may be less than, 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 (meth) acrylic acid ester having an alicyclic hydrocarbon group.

In some embodiments, the monomer component for preparing polymer B preferably comprises at least MMA. Copolymerizing MMA can be a useful tool to adjust T _m1 to the preferred range disclosed herein. In addition, according to polymer B copolymerized with MMA, a large N ₈₀ / N ₅₀ large adhesive sheet 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, more than 50% by weight, may be more than 55% by weight, may be more than 60% by weight, and 65% by weight It may be more than 70% by weight. Further, the ratio of MMA in the total amount of the (meth) acrylic monomers is _{sufficient as} long as T _m1 is 100 ° C. or less, and usually 95 wt% or less is appropriate, and 90 wt% or less is also appropriate. Or 85% by weight 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 exemplified above as the monomer that can be used when the polymer A is an acrylic polymer, acid anhydride group containing 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 amino alkyls, vinyl esters, vinyl ethers, olefins, (meth) acrylic acid ester having aromatic hydrocarbon group, heterocycle-containing (meth) acrylate, halogen atom-containing (meth) acrylate, terpene compound Resulting from the conductor alcohol (meth) acrylic acid ester.

  As still another example of a monomer that can be included together with the monomer S1 as a monomer unit constituting the polymer B, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di ( Oxyalkylene (meth) acrylates such as meta) acrylates, propylene glycol di (meth) acrylates, dipropylene glycol di (meth) acrylates, tripropylene glycol di (meth) acrylates; monomers having a polyoxyalkylene skeleton, such as polyethylene glycol And a polymerizable functional group such as (meth) acryloyl group, vinyl group and allyl group at one end of a polyoxyalkylene chain such as polypropylene glycol, etc. Polymerizable polyoxyalkylene ether having an ether structure (alkyl ether, aryl ether, aryl alkyl 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 (meth) acrylates; polyvalents such as trimethylolpropane tri (meth) acrylates Meta) acrylate: vinylidene halide, halogenated vinyl compounds such as (meth) acrylic acid 2-chloroethyl; 2-vinyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2- Oxazoline such as oxazoline Containing monomers; Aziridine group-containing monomers such as (meth) acryloyl aziridine, (meth) acrylic acid 2-aziridinyl ethyl; etc. (meth) acrylic acid 2- hydroxyethyl, (meth) acrylic acid 2-hydroxypropyl, Hydroxyl group-containing vinyl monomers such as adducts of lactones and (meth) acrylic acid-2-hydroxyethyl; fluorine-containing vinyl monomers such as fluorine-substituted (meth) acrylic acid alkyl esters; 2-chloroethyl vinyl ether, vinyl monochloroacetate, etc. Reactive halogen-containing vinyl monomers; organosilicon-containing vinyls 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, for example, 1,000 or more, or 5,000 or more. If the Mw of the polymer B is too low, the increase in adhesion may be insufficient. In some preferred embodiments, the Mw of the polymer B may be, for example, 10000 or more, 12000 or more, 15000 or more, 17000 or more, or 20000 or more. In addition, Mw of the polymer B may be, for example, 100,000 or less, and may be 70000 or less. If the Mw of the polymer B is too high, the initial tack may not be sufficiently suppressed. In some preferred embodiments, the Mw of polymer B may be, for example, 50000 or less, may be less than 50000, may be less than 40000, may be less than 35000, may be 30000 or less, 28000 or less, or 25000 or less . When the Mw of the polymer B is within the range of any of the upper limit and the lower limit described above, the compatibility and mobility in the pressure-sensitive adhesive layer can be easily adjusted to an appropriate range, and good reworkability and adhesion in the initial stage of application It becomes easy to implement | achieve the adhesive sheet which makes compatible with the strong adhesiveness after a force rise by a high level.

  The polymer B can be produced, for example, by polymerizing the above-described monomer by a known method such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, photopolymerization and the like.

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

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

  Although not particularly limited, the use amount of the polymer B can be, for example, 0.1 parts by weight or more with respect to 100 parts by weight of the polymer A, and from the viewpoint of obtaining higher effects, 0.3 It is good also as a weight part or more, good also as a 0.4 weight part or more, and good also as 0.5 weight part or more. From the viewpoint of improving reworkability, etc., in some embodiments, the amount of polymer B used relative to 100 parts by weight of polymer A may be 1 part by weight or more, 2 parts by weight or more, or 3 parts by weight or more. The amount of polymer B used relative to 100 parts by weight of the polymer A may be, for example, 75 parts by weight or less, 60 parts by weight or less, or 50 parts by weight or less. In some embodiments, the amount of polymer B used can be, for example, 40 parts by weight or less, and 35 parts by weight or less in some embodiments, from the viewpoint of avoiding excessive reduction in the cohesive force of the pressure-sensitive adhesive layer 30 parts by weight or less or 25 parts by weight or less. From the viewpoint of obtaining higher adhesion 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, 10 parts by weight It is good also as a part or less. In some embodiments of the pressure-sensitive adhesive sheet disclosed herein, the amount of polymer B used relative to 100 parts by weight of polymer A may be, for example, less than 10 parts by weight, may be 8 parts by weight or less, 5 parts by weight or less, or 5 parts by weight It may be less than 4 parts by weight, 3 parts by weight or less.

  The pressure-sensitive adhesive layer may optionally contain a polymer (optional polymer) other than the polymer A and the polymer B, 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 entire 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 entire polymer component. The pressure-sensitive adhesive layer may contain substantially no polymer other than the polymer A and the polymer B.

(Crosslinking agent)
In the pressure-sensitive adhesive layer, a crosslinking agent may be used as needed for the purpose of adjusting the cohesion force and the like. As the crosslinking agent, crosslinking agents known in the field of pressure-sensitive adhesives can be used. For example, epoxy-based crosslinking agents, isocyanate-based crosslinking agents, silicone-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, silane-based crosslinking agents A crosslinking agent, an alkyl etherified melamine based crosslinking agent, a metal chelate based crosslinking agent and the like can be mentioned. In particular, isocyanate crosslinking agents, epoxy crosslinking agents, and metal chelate crosslinking agents can be suitably used. The crosslinking agents can be used singly or in combination of two or more.

  Specifically, examples of isocyanate-based crosslinking agents include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenyl (meth) diisocyanate, hydrogenated diphenyl (meth) diisocyanate And tetramethyl xylylene diisocyanate, naphthalene diisocyanate, triphenyl (meth) triisocyanate, polymethylene polyphenyl isocyanate, and adducts thereof with polyols such as trimethylolpropane. Alternatively, a compound having at least one or more isocyanate groups and one or more unsaturated bonds in one molecule, specifically, 2-isocyanatoethyl (meth) acrylate, etc. is also used as an isocyanate-based crosslinking agent. Can. These can be used singly or in combination of two or more.

  Examples of epoxy crosslinking agents include bisphenol A, epoxy resins of epichlorohydrin type, ethylene glycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol glycidyl ether, trimethylolpropane triol. Glycidyl ether, diglycidyl aniline, diamine glycidyl amine, N, N, N ', N'-tetraglycidyl-m-xylylenediamine and 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane etc. Can. These can be used singly or in combination of two or more.

  Examples of the metal chelate compound include aluminum, iron, tin, titanium, nickel and the like as a metal component, and acetylene, methyl acetoacetate, ethyl lactate and the like as a chelate component. These can be used singly or in combination of two or more.

The amount used in the case of using the crosslinking agent is not particularly limited, and can be, for example, an amount exceeding 0 parts by weight with respect to 100 parts by weight of the polymer A. The amount of the crosslinking agent used can be, for example, 0.01 parts by weight or more, preferably 0.05 parts by weight or more, per 100 parts by weight of the polymer A. By increasing the amount of 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 use amount of the crosslinking agent relative to 100 parts by weight of the polymer A may be 0.1 parts by weight or more, 0.5 parts by weight or more, or even 1 part by weight or more Good. On the other hand, from the viewpoint of avoiding a decrease in tack due to excessive cohesion, the amount of the crosslinking agent used per 100 parts by weight of the polymer A is usually 15 parts by weight or less, and may be 10 parts by weight or less. It may be 5 parts by weight or less. Not using too much a crosslinking agent may be advantageous from the viewpoint of facilitating the realization of a high N ₈₀ / N ₅₀ adhesive sheet.

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

Although not particularly limited, if the pressure-sensitive adhesive layer is used isocyanate crosslinking agent in a configuration that includes a hydroxyl group-containing monomer as a monomer unit, the amount W _OH of the hydroxyl group-containing monomer to the amount W _NCO of isocyanate crosslinking agent, The amount of W _OH / W _NCO can be 2 or more on a weight basis. By increasing the amount of the hydroxyl group-containing monomer to the isocyanate crosslinking agent as described above, a crosslinked structure suitable for greatly increasing the adhesion after heating with respect to the adhesion in the initial stage of application can be formed. In some embodiments, W _OH / W _NCO may be 3 or more, 5 or more, 10 or more, 20 or more, or even 30 or more. 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.

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

A polyfunctional monomer can be used for the adhesive layer as needed. Multifunctional monomers can serve for purposes such as adjustment of cohesion by being used in place of or in combination with the above-mentioned crosslinking agents. For example, in the pressure-sensitive adhesive layer formed from a photocurable pressure-sensitive adhesive composition, a polyfunctional monomer can be preferably used.
Examples of multifunctional monomers 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, trimethylol propane tri (meth) acrylate, tetramethylol methane tri (meth) acrylate, allyl (meth) acrylate, bi Le (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyl diol (meth) acrylate, hexyl di (meth) acrylate. Among them, trimethylolpropane tri (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and dipentaerythritol hexa (meth) acrylate can be suitably used. The polyfunctional monomers can be used alone or in combination of two or more.

The amount of the polyfunctional monomer used varies depending on the molecular weight, the number of functional groups, etc., but normally, it is appropriate to be in the range of about 0.01 part by weight to 3.0 parts by weight with respect to 100 parts by weight of the polymer A . In some embodiments, the amount of multifunctional 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 amount of the polyfunctional monomer used, the adhesive strength at the initial stage of application is suppressed, and the reworkability tends to be improved. On the other hand, the amount of the polyfunctional monomer used may be 2.0 parts by weight or less, and even 1.0 part by weight or less with respect to 100 parts by weight of the polymer A, from the viewpoint of avoiding a decrease in tack due to excessive cohesion. It may well be 0.5 parts by weight or less. Not using too much amount of the polyfunctional monomer may be advantageous from the viewpoint of facilitating the realization of a high N ₈₀ / N ₅₀ adhesive sheet.

(Tackifying resin)
The pressure-sensitive adhesive layer can optionally contain a tackifying resin. The tackifier resin is not particularly limited, and, for example, rosin-based tackifier resin, terpene-based tackifier resin, phenol-based tackifier resin, hydrocarbon-based tackifier resin, ketone-based tackifier resin, polyamide-based tackifier resin, Epoxy tackifying resins, elastomeric tackifying resins and the like can be mentioned. The tackifying resin can be used singly or in combination of two or more.

Examples of rosin-based tackifying resins include unmodified rosin (raw rosin) such as gum rosin, wood rosin, tall oil rosin, and modified rosin obtained by modifying these unmodified rosins by polymerization, disproportionation, hydrogenation, etc. In addition to polymerized rosins, stabilized rosins, disproportionated rosins, fully hydrogenated rosins, partially hydrogenated rosins, and other chemically modified rosins, various rosin derivatives may be mentioned.
Examples of the rosin derivatives include
Rosin phenolic resins obtained by thermally polymerizing a rosin (unmodified rosin, modified rosin, various rosin derivatives, etc.) with an acid catalyst and thermally polymerizing it;
Ester compounds of rosin obtained by esterifying unmodified rosin with alcohol (unmodified rosin ester), modified rosin such as polymerized rosin, stabilized rosin, disproportionated rosin, fully hydrogenated rosin, partially hydrogenated rosin, etc. Rosin ester-based resins such as ester compounds of modified rosin esterified by esterification (polymerized rosin ester, stabilized rosin ester, disproportionated rosin ester, fully hydrogenated rosin ester, partially hydrogenated rosin ester, etc.);
Unsaturated fatty acid modified rosin based resins modified with unsaturated fatty acids such as unmodified rosins and modified rosins (polymerized rosins, stabilized rosins, disproportionated rosins, fully hydrogenated rosins, partially hydrogenated rosins, etc.);
Unsaturated fatty acid modified rosin ester resin modified from rosin ester resin with unsaturated fatty acid;
Carboxyl group in unmodified rosin, modified rosin (polymerized rosin, stabilized rosin, disproportionated rosin, completely hydrogenated rosin, partially hydrogenated rosin, etc.), unsaturated fatty acid modified rosin resin and unsaturated fatty acid modified rosin ester resin Rosin alcohol resin with reduction treatment;
Examples include unmodified rosin, modified rosin, and metal salts of rosin resins (in particular, rosin ester resins) such as various rosin derivatives.

  Examples of terpene-based tackifying resins include terpene-based resins such as α-pinene polymers, β-pinene polymers, and dipentene polymers, and those terpene-based resins modified (phenol modification, aromatic modification, hydrogenation modification And modified terpene resins (eg, terpene phenol resins, styrene modified terpene resins, aromatic modified terpene resins, hydrogenated terpene resins, etc.) and the like.

  Examples of the phenol-based tackifying resin include condensates of various phenols (eg, phenol, m-cresol, 3,5-xylenol, p-alkylphenol, resorcin etc.) with formaldehyde (eg, alkylphenol-based resin, xylene formaldehyde) And resins such as resoles obtained by subjecting the above-mentioned phenols and formaldehyde to an addition reaction with an alkali catalyst, and novolaks obtained by subjecting the above-mentioned phenols and formaldehyde to a condensation reaction with an acid catalyst.

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

  As a commercial item of the polymerization rosin ester which can be preferably used, the brand names "Pencel D-125", "Pencel D-135", "Pencel D-160", "Pencel KK", "Pencel" by Arakawa Chemical Industries, Ltd. are used. C "and the like, but is not limited thereto.

  As a commercial item of the terpene phenol-type resin which can be used preferably, the brand name "YS poly star S-145", "YS poly star G-125", "YS poly star N125", "YS poly star U-115" by Yashara Chemical Co., Ltd. are manufactured. Arakawa Chemical Industry Co., Ltd. trade name "Tamanor 803L", "Tamanor 901", Sumitomo Bakelite Co., Ltd. trade name "Sumilite resin PR-12603", etc. are exemplified, but not limited thereto.

  The content of the tackifier resin is not particularly limited, and can be set so as to exhibit appropriate adhesion performance depending on the purpose and application. The content of the tackifier resin (the total amount of two or more tackifier resins, if any, of the two or more tackifier resins) relative to 100 parts by weight of the polymer A can be, for example, about 5 to 500 parts by weight.

As the tackifying 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 the softening point equal to or more than the lower limit value described above, it is easy to obtain a pressure-sensitive adhesive sheet satisfying N ₈₀ / N ₅₀ 55. The upper limit of the softening point is not particularly limited, and may be, for example, about 200 ° C. or less (typically, 180 ° C. or less). In addition, the softening point of tackifying resin can be measured based on the softening point test method (ring and ball method) prescribed | regulated to JISK2207.

  In addition, the pressure-sensitive adhesive layer in the art disclosed herein is a leveling agent, a plasticizer, a softener, a coloring agent (dye, pigment, etc.), a filler, an antistatic agent, as long as the effects of the present invention are not significantly impaired. If necessary, known additives which can be used in the pressure-sensitive adhesive may be contained, such as anti-aging agents, ultraviolet light absorbers, antioxidants, light stabilizers, preservatives and the like.

  The pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive sheet disclosed herein may be a cured layer of a pressure-sensitive adhesive composition. That is, the pressure-sensitive adhesive layer is formed by appropriately applying (for example, applying) a pressure-sensitive adhesive composition such as a water dispersion type, a solvent type, a photocurable type, a hot melt type to a suitable surface, and then performing curing treatment appropriately. obtain. When two or more curing treatments (drying, crosslinking, polymerization, cooling, etc.) are carried out, these can be carried out simultaneously or in multiple stages. In a pressure-sensitive adhesive composition using a partially polymerized product of monomer components (acrylic polymer syrup), a final copolymerization reaction is typically performed as the above-mentioned curing treatment. That is, the partially polymerized product is subjected to a further copolymerization reaction to form a completely polymerized product. For example, if it is a photocurable pressure-sensitive adhesive composition, light irradiation is carried out. If necessary, curing treatment such as crosslinking or drying may be performed. For example, when it is necessary to dry with a photocurable pressure-sensitive adhesive composition, light curing may be performed after drying. In the case of a pressure-sensitive adhesive composition using a completely polymerized product, typically, a treatment such as drying (heat drying) or crosslinking is carried out as the curing treatment as necessary.

  The application of the pressure-sensitive adhesive composition can be carried out using, for example, a conventional coater such as a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, or a spray coater.

  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 20 μm or more. The increase in thickness of the pressure-sensitive adhesive layer tends to increase the adhesion after heating. 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, or 50 μm or less, 40 μm Or less. If the thickness of the pressure-sensitive adhesive layer is not too large, it may be advantageous from the viewpoint of thinning the pressure-sensitive adhesive sheet and preventing cohesive failure of the pressure-sensitive adhesive layer. In the case of a pressure-sensitive adhesive sheet having a first pressure-sensitive adhesive layer and a 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 also be selected from the same range. In the case of a substrate-less pressure-sensitive adhesive sheet, the thickness of the pressure-sensitive adhesive sheet is the same as the thickness of the pressure-sensitive adhesive layer.

  Although not particularly limited, the gel fraction of the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is usually suitably in the range of 20.0% to 99.0%, and 30.0% to 90. 0. It is desirable to be in the range of 0%. By setting the gel fraction in the above-mentioned range, it becomes easy to realize a pressure-sensitive adhesive sheet in which the reworkability in the initial stage of bonding and the strong tackiness after the increase in tackiness are compatible at a high level. 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 with a porous polytetrafluoroethylene membrane (weight Wg ₂ ) having an average pore diameter of 0.2 μm in a drawstring shape, and the mouth is tied with a tacho yarn (weight Wg ₃ ). As the porous polytetrafluoroethylene membrane, a trade name "Nitoflon (registered trademark) NTF 1122" (Nitto Denko Corp., average pore diameter 0.2 μm, porosity 75%, thickness 85 μm) or an equivalent thereof is used. This packet is immersed in 50 mL of ethyl acetate and kept at room temperature (typically 23 ° C.) for 7 days to elute the sol (ethyl acetate soluble) in the adhesive outside the membrane. Then, the package is taken out, the ethyl acetate adhering to the outer surface is wiped off, the package is dried at 130 ° C. for 2 hours, and the weight (Wg ₄ ) of the package 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

<Supporting substrate>
The pressure-sensitive adhesive sheet according to some embodiments may be in the form of a substrate-attached pressure-sensitive adhesive sheet provided with a pressure-sensitive adhesive layer on one side or both sides of a support base. The material of the supporting substrate is not particularly limited, and can be appropriately selected according to the purpose of use, mode of use, and the like of the pressure-sensitive adhesive sheet. Non-limiting examples of the base material that can be used include polyolefin films mainly composed of polyolefins such as polypropylene and ethylene-propylene copolymer, polyester films mainly composed of polyesters such as polyethylene terephthalate and polybutylene terephthalate, Plastic films such as polyvinyl chloride film mainly composed of polyvinyl chloride; foam sheets composed of foams such as polyurethane foam, polyethylene foam, polychloroprene foam etc. Various fibrous materials (natural fibers such as hemp, cotton, etc. May be polyester, synthetic fibers such as vinylon, semi-synthetic fibers such as acetate, etc.) woven or non-woven fabric by single or mixed spinning etc .; paper such as Japanese paper, wood free paper, kraft paper, crepe paper etc .; Metal foil such as copper foil; That. It may be a base material of the composition which combined these. 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 an inorganic fiber such as glass cloth, and the like.

  As a substrate of the pressure-sensitive adhesive sheet disclosed herein, various film substrates 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, and a porous layer and a non-porous layer The base may have a laminated structure. In some embodiments, it is preferable to use, as the film substrate, one including a resin film that can be independently maintained in shape (self-supporting or independent) as a base film. Here, "resin film" means a non-porous structure and a resin film which is substantially free of bubbles (voidless). Therefore, the said resin film is the concept distinguished from a foam film and a nonwoven fabric. As the resin film, those which can be independently maintained in shape (self-supporting or independent) can be preferably used. The resin film may have a single-layer structure or a multilayer structure of 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), polyamide imide (PAI), polyetheretherketone (PEEK) ), Fluorine resin such as polyether sulfone (PES), polyphenylene sulfide (PPS), polycarbonate (PC), polyurethane (PU), ethylene-vinyl acetate copolymer (EVA), polytetrafluoroethylene (PTFE), acrylic resin And resins such as polyacrylate, polystyrene, polyvinyl chloride and polyvinylidene chloride can be used. The resin film may be formed of a resin material containing one kind of such a resin alone, or may be formed of a resin material in which two or more kinds are blended. Good. The resin film may be unstretched or may be stretched (for example, uniaxially stretched or biaxially stretched).

  Polyester-based resin, PPS resin, and polyolefin resin are mentioned as a suitable example of the resin material which comprises a resin film. Here, the polyester-based resin refers to a resin containing polyester at a ratio of more than 50% by weight. Similarly, PPS resin refers to a resin containing PPS in a proportion exceeding 50% by weight, and polyolefin resin refers to a resin containing 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.

  As a dicarboxylic acid which comprises the said polyester, phthalic acid, isophthalic acid, a terephthalic acid, 2-methylterephthalic acid, 5-sulfoisophthalic acid, 4,4'- diphenyl dicarboxylic acid, 4,4'- diphenyl ether dicarboxylic acid, for example 4,4′-diphenyl ketone dicarboxylic acid, 4,4′-diphenoxy ethane dicarboxylic acid, 4,4′-diphenyl sulfone dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 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 malic acid, suberic acid, azelaic acid, sebacic acid and dodecanoic acid; unsaturated dicarboxylic acids such as maleic acid, maleic anhydride and fumaric acid; derivatives thereof (for example, the above dicarboxylic acids such as terephthalic acid) And lower alkyl esters of These can be used singly or in combination of two or more. Aromatic dicarboxylic acids are preferred from the viewpoint of strength and the like. Among them, preferred dicarboxylic acids include terephthalic acid and 2,6-naphthalene dicarboxylic acid. For example, 50% by weight or more (for example, 80% by weight or more, typically 95% by weight or more) of dicarboxylic acids constituting the above-mentioned polyester is terephthalic acid, 2,6-naphthalenedicarboxylic acid or a combination thereof Is preferred. The dicarboxylic acid may consist essentially 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 above 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 and the like; 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethylol, 1,4 Cycloaliphatic diols such as cyclohexane dimethylol, xylylene glycol, 4,4′-dihydroxybiphenyl, 2,2-bis (4′-hydroxyphenyl) propane, bis (4-hydroxyphenyl) sul Aromatic diols such emissions; and the like. These can be used singly or in combination of two or more. Among them, 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 (eg, 80% by weight or more, typically 95% by weight or more). The diol may consist essentially of ethylene glycol only.

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

  As a polyolefin resin, it is possible to use one type of polyolefin alone or a combination of two or more types of polyolefins. The polyolefin may be, for example, a homopolymer of α-olefin, a copolymer of two or more α-olefins, a copolymer of one or more α-olefins and another vinyl monomer, and the like. Specific examples thereof include ethylene-propylene copolymers such as polyethylene (PE), polypropylene (PP), poly-1-butene, poly-4-methyl-1-pentene, ethylene-propylene rubber (EPR), ethylene-propylene- A butene copolymer, an ethylene-butene copolymer, an ethylene-vinyl alcohol copolymer, an ethylene-ethyl acrylate copolymer, etc. are mentioned. Both low density (LD) and high density (HD) polyolefins can be used. Examples of polyolefin resin films include non-oriented polypropylene (CPP) film, biaxially oriented polypropylene (OPP) film, low density polyethylene (LDPE) film, linear low density polyethylene (LLDPE) film, medium density polyethylene (MDPE) A film, a high density polyethylene (HDPE) film, a polyethylene (PE) film in which two or more polyethylenes (PE) are blended, a PP / PE blend film in which polypropylene (PP) and polyethylene (PE) are blended, and the like can be mentioned.

  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 preferred base films from the viewpoint of strength and dimensional stability include PET films, PEN films, PPS films and PEEK films. PET films and PPS films are particularly preferred from the viewpoint of the availability of the substrate and the like, and PET films are particularly preferred.

  For resin films, known as light stabilizers, antioxidants, antistatic agents, colorants (dyes, pigments, etc.), fillers, slip agents, antiblocking agents, etc. to the extent that the effects of the present invention are not significantly impaired. The additives of the above can be blended as needed. The compounding amount of the additive is not particularly limited, and can be appropriately set according to the application of the pressure-sensitive adhesive sheet and the like.

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

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

  The thickness of the substrate is not particularly limited, and may be selected according to the purpose of use, mode of use, and the like of the pressure-sensitive adhesive sheet. The thickness of the substrate may be, for example, 1000 μm or less. In some embodiments, the thickness of the substrate may be, for example, 500 μm or less, 300 μm or less, or 250 μm or less, from the viewpoint of handleability and processability of the pressure-sensitive adhesive sheet, and may be 200 μm or less It may be the following. In some embodiments, the thickness of the substrate may be, for example, 160 μm or less, may be 130 μm or less, and 100 μm or less, from the viewpoint of reducing the size and weight of the product to which the adhesive sheet is applied. 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 ability to follow the surface shape of the adherend tend to be improved. From the viewpoint of handleability and processability, the thickness of the substrate may be, for example, 2 μm or more, 5 μm or more, 10 μm or more, 20 μm or more, 25 μm or more, or 25 μm or more. 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 of an adherend, support, impact relaxation, etc., a substrate having a thickness of 30 μm or more can be preferably employed.

  On the first surface of the substrate, conventionally known surfaces such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, formation of an undercoat layer by application of an undercoat (primer), etc. Processing may be performed. Such surface treatment may be treatment for improving the anchorability of the pressure-sensitive adhesive layer to the substrate. For example, in a pressure-sensitive adhesive sheet provided with a base material containing a resin film as a base film, a base material subjected to such an anchorage property improvement treatment can be preferably adopted. The above surface treatments can be applied alone or in combination. The composition of the primer used to form 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, and preferably about 0.1 μm to 1 μm. Examples of other treatments that may be applied to the first surface of the substrate as required 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 peeling treatment or antistatic treatment as necessary. The surface treatment conventionally known, such as, may be given. For example, the surface of the back of the substrate is surface-treated with a release treatment agent (typically, by providing a release layer with a release treatment agent), whereby the unwinding force of the pressure-sensitive adhesive sheet in the form of a roll is obtained. It can be lightened. As the release agent, silicone release agents, long chain alkyl release agents, olefin release agents, fluorine release agents, fatty acid amide release agents, molybdenum sulfide, silica powder, etc. can be used. . In addition, the second surface of the substrate is subjected to treatments such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment and the like for the purpose of improving the printability, reducing the light reflectivity, and improving the laminating property. It may be done. In the case of the double-sided pressure-sensitive adhesive sheet, the second surface of the substrate is subjected to the same surface treatment as exemplified above as the surface treatment which can be applied to the first surface of the substrate, if necessary. It is also good. The surface treatment to be applied to the first surface of the substrate and the surface treatment to be applied to the second surface may be the same as or different from each other.

<Adhesive sheet>
(Characteristics of adhesive sheet etc.)
The PSA sheet disclosed herein, the ratio of adhesive strength _{N 80} (after heating adhesive strength) with respect to adhesive strength _{N 50,} i.e., _N 80 _{/ N 50} is 5 or more, joining initially joined by a temperature of about 50 ° C. Also in the usage mode to be obtained, good reworkability is exhibited, and adhesion can be greatly increased by subsequent heating or the like. From the viewpoint of obtaining higher effects, 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 production easiness and economy of the pressure-sensitive adhesive sheet. The pressure-sensitive adhesive sheet disclosed herein can be suitably implemented in an aspect in which 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 pressure-sensitive adhesive sheet disclosed herein, the ratio of adhesion N ₅₀ [N / 25 mm] to adhesion N ₂₃ [N / 25 mm], ie, N ₅₀ / N ₂₃ May for example be less than 10, preferably less than 7, and may be less than 5 or less than 4. A pressure-sensitive adhesive sheet having a small N ₅₀ / N ₂₃ tends to exhibit good reworkability even in a usage mode in which a temperature of about 50 ° C. can be added 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, and may be 1.2 or more, for example.

Although not particularly limited, in some embodiments of the pressure-sensitive adhesive sheet disclosed herein, the ratio of adhesion N ₈₀ [N / 25 mm] to adhesion N ₂₃ [N / 25 mm], ie N ₈₀ / N ₂₃ Is, for example, 7 or more, 10 or more, or 15 or more. According to the adhesive sheet having a large N ₈₀ / N _23, the low tackiness in the initial stage of sticking and the strong tackiness after the rise in tackiness can be exhibited at a higher level. The pressure-sensitive adhesive sheet disclosed herein can also be suitably implemented in an embodiment in which 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 production easiness and economy of the pressure-sensitive adhesive sheet.

Here, the adhesive strength N ₂₃ [N / 25 mm] is crimped to a stainless steel (SUS) plate as an adherend and left in an environment of 23 ° C., 50% RH for 30 minutes, and then peeling angle 180 °, tension It is grasped by measuring the 180 ° peel strength at a speed of 300 mm / min. The adhesive strength N ₅₀ [N / 25 mm] was crimped to a stainless steel (SUS) plate as an adherend, 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 the 180 ° peel strength at a peeling angle of 180 ° and a tensile speed of 300 mm / min. The adhesive strength N ₈₀ [N / 25 mm] is crimped to a SUS plate as an adherend, heated at 80 ° C. for 5 minutes, and then left in an environment of 23 ° C. and 50% RH for 30 minutes. It is grasped by measuring the 180 ° peel strength at a tensile speed of 300 mm / min. The adherend, in any of the measurement of the adhesive force _{N 23, N 50, N 80} , SUS304BA plate is used. In the measurement, if necessary, a 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 to reinforce the adhesive sheet. The adhesive strengths N ₂₃ , N ₅₀ and N ₈₀ can be more specifically measured according to the method described in the examples described later.

Although not particularly limited, in some embodiments of the pressure-sensitive adhesive sheet disclosed herein, the pressure-sensitive adhesive strength N ₂₃ of the pressure-sensitive adhesive sheet may be, for example, 2.0 N / 25 mm or less, and less than 1.5 N / 25 mm 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 adhesion N ₂₃ is not particularly limited. It may be 0.01 N / 25 mm or more. The adhesive strength N ₂₃ is usually preferably 0.1 N / 25 mm or more from the viewpoint of the workability of bonding to the adherend, the prevention of positional deviation before the adhesive strength is increased, and the like. In some embodiments, the adhesion N ₂₃ may be, for example, 0.2 N / 25 mm or more, 0.3 N / 25 mm or more, 0.4 N / 25 mm or more, from the viewpoint of improving adhesion after heating, etc. However, it may be 0.5 N / 25 mm or more.

Although not particularly limited, in some embodiments of the pressure-sensitive adhesive sheet disclosed herein, the pressure-sensitive adhesive strength N ₅₀ of the pressure-sensitive adhesive sheet may be, for example, 7 N / 25 mm or less, 5 N / 25 mm or less, 4 N / 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 adhesive strength N ₅₀ is preferable from the viewpoint of exhibiting good reworkability even in a use mode in which a temperature of about 50 ° C. can be added at the initial stage of application. The lower limit of the adhesion N ₅₀ is not particularly limited. It may be 0.05 N / 25 mm or more. It is appropriate that the adhesive strength N ₅₀ is usually 0.1 N / 25 mm or more from the viewpoint of preventing positional deviation before the adhesive strength is increased. From the viewpoint of improving adhesion after heating, etc., in some embodiments, the adhesion N ₅₀ may be, for example, 0.2 N / 25 mm or more, may be 0.5 N / 25 mm or more, 0.7 N / 25 mm or more May be.

Although not particularly limited, in some embodiments of the pressure-sensitive adhesive sheet disclosed herein, the pressure-sensitive adhesive strength N ₈₀ (adhesive strength after heating) of the pressure-sensitive adhesive sheet may be, for example, 5 N / 25 mm or more, 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 adhesion after heating is not particularly limited. In some aspects, 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 viewpoint of production ease and economy of the pressure-sensitive adhesive sheet.

Although not particularly limited, in some embodiments of the pressure-sensitive adhesive sheet disclosed herein, the difference between the adhesive strength N ₅₀ [N / 25 mm] and the adhesive strength N ₂₃ [N / 25 mm], ie, N ₅₀ -N Generally, ₂₃ is preferably less than 5N / 25 mm, for example, may be less than 4N / 25 mm, may be less than 3N / 25 mm, may be less than 2.5 N / 25 mm, or may be less than 2 N / 25 mm. It may be less than 5 N / 25 mm. A pressure-sensitive adhesive sheet having a small N ₅₀ -N ₂₃ tends to exhibit good reworkability even in a usage mode in which a temperature of about 50 ° C. can be added 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 0 N / 25 mm or more, and may be 0.2 N / 25 mm or more.

Although not particularly limited, the adhesive strength N ₈₀ [N / 25 mm] and the adhesive strength to the difference between the adhesive strength N ₅₀ [N / 25 mm] and the adhesive strength N ₂₃ [N / 25 mm] of the adhesive sheet disclosed herein The ratio of the difference to the force N ₅₀ [N / 25 mm], that is, (N ₈₀ -N ₅₀ ) / (N ₅₀ -N ₂₃ ) may be, for example, 2 or more. When the value of (N ₈₀ -N ₅₀ ) / (N ₅₀ -N ₂₃ ) is larger, the increase in adhesion after heating is higher than the adhesion initial time in the usage mode in which a temperature of about 50 ° C. can be added. It means that the degree is greater. In some embodiments, (N ₈₀ -N ₅₀ ) / (N ₅₀ -N ₂₃ ) may be, for example, 3 or more, 5 or more, 7 or more, 10 or more, or 15 or more. 20 or more may be sufficient. The upper limit of (N ₈₀ -N ₅₀ ) / (N ₅₀ -N ₂₃ ) is not particularly limited, and may be, for example, 100 or less.

  The adhesive strength after heating of the pressure-sensitive adhesive sheet disclosed herein represents one characteristic of the pressure-sensitive adhesive sheet, and the use mode of the pressure-sensitive adhesive sheet is not limited. In other words, the usage mode of the pressure-sensitive adhesive sheet disclosed herein is not limited to the mode in which heating at 80 ° C. for 5 minutes is performed, and for example, room temperature range (usually 20 ° C. to 30 ° C., typically 23 ° C. to 25) It can be used also in the aspect which does not perform especially the process heated more than ° C). Also in this mode of use, the adhesive strength is increased in the long term, and strong bonding can be realized. In addition, the pressure-sensitive adhesive sheet disclosed herein can promote an increase in adhesion by performing heat treatment at a temperature higher than 50 ° C. at an arbitrary timing after bonding. The heating temperature in the heat treatment is not particularly limited, and can be set in consideration of workability, economy, heat resistance of the base material of the pressure-sensitive adhesive sheet, 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. The heating temperature may be, for example, 55 ° C. or more, 60 ° C. or more, or 70 ° C. or more, may be 80 ° C. or more, or 100 ° C. or more. With higher heating temperatures, the tack can be increased by a shorter treatment. 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. Alternatively, heat treatment may be performed for a longer period of time as long as no significant thermal deterioration occurs in the pressure-sensitive adhesive sheet or the adherend. Note that the heat treatment may be performed at one time or may be performed plural times.

(Adhesive sheet with substrate)
When the pressure-sensitive adhesive sheet disclosed herein is in the form of a substrate-attached pressure-sensitive adhesive sheet, 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 May be. In some embodiments, the thickness of the pressure-sensitive adhesive sheet may be, for example, 200 μm or less, and may be 175 μm or less, from the viewpoint of reducing the size, weight and thickness of the product to which the pressure-sensitive adhesive sheet is applied. It may be 140 μm or less, 120 μm or less, or 100 μm or less (eg, less than 100 μm). Further, 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 and the like. 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 the pressure-sensitive adhesive sheet is not particularly limited.
In addition, the thickness of an adhesive sheet means the thickness of the part affixed on a to-be-adhered body. For example, in the pressure-sensitive adhesive sheet 1 configured as shown in FIG. 1, the thickness refers to the thickness from the pressure-sensitive surface 21A of the pressure-sensitive adhesive sheet 1 to the second surface 10B of the base 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, in a mode in which Ts / Ta is larger than one. 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. It is also good. For example, in a pressure-sensitive adhesive sheet that can be used for the purpose of reinforcement, support, impact relaxation, etc. of adherends, the increase in Ts / Ta tends to make it possible to exert good effects even if the pressure-sensitive adhesive sheet is thinned. In some embodiments, Ts / Ta may be 2 or more (e.g., more than 2), 3 or more, or 4 or more. Further, Ts / Ta may be, for example, 50 or less, and may be 20 or less. Ts / Ta may be, for example, 10 or less, and may be 8 or less, from the viewpoint of facilitating exerting high adhesion after heating even if the pressure-sensitive adhesive sheet is thinned.

The pressure-sensitive adhesive layer is preferably fixed to the support substrate. The above-mentioned adhesion is a pressure-sensitive adhesive sheet in which the adhesive strength is increased after the adhesion to the adherend, to such an extent that the peeling at the interface between the pressure-sensitive adhesive layer and the support substrate does not occur when the pressure-sensitive adhesive sheet is peeled from the adherend And the pressure-sensitive adhesive layer exhibits sufficient anchoring to the support substrate. According to the pressure-sensitive adhesive sheet with a substrate in which the pressure-sensitive adhesive layer is fixed to the supporting substrate, the adherend and the supporting substrate can be firmly integrated. By this, for example, functions such as reinforcement of an adherend, support, and shock relaxation can be exhibited effectively. As a suitable example of a pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer is fixed to a substrate, an adhesive force of 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 an adherend Between the pressure-sensitive adhesive layer and the supporting substrate when peeling from the adherend while developing a peel angle of 180 ° measured at a peeling angle of 180 ° and a tensile speed of 300 mm / min) A pressure-sensitive adhesive sheet which does not cause peeling (dropping) may be mentioned. A pressure-sensitive adhesive sheet having a post-heating adhesive strength (N ₈₀ ) of 15 N / 25 mm or more and having no anchorage breakage at the time of measurement of the post-heating adhesive strength corresponds to a pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive layer is fixed to a substrate This is one preferred example.

  The pressure-sensitive adhesive sheet disclosed herein includes, for example, bringing a liquid pressure-sensitive adhesive composition into contact with the first surface of a substrate, and curing the pressure-sensitive adhesive composition on the first surface to form a pressure-sensitive adhesive layer. Can be preferably produced by a method comprising: The curing of the pressure-sensitive adhesive composition may involve one or more of drying, crosslinking, polymerization, cooling and the like of the pressure-sensitive adhesive composition. Thus, according to the method of forming a pressure-sensitive adhesive layer by curing the liquid pressure-sensitive adhesive composition on the first surface of the substrate, the cured pressure-sensitive adhesive layer is attached to the first surface of the substrate. The anchorability of the pressure-sensitive adhesive layer to the substrate can be enhanced as compared to the method of arranging the pressure-sensitive adhesive layer on the first surface. The adhesive sheet which the adhesive layer adhered to the base material can be suitably manufactured using this.

  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 in which the above-mentioned pressure-sensitive adhesive composition is directly applied to the first surface of the substrate can be employed. The second surface of the pressure-sensitive adhesive layer adheres to the first surface of the substrate by bringing the first surface (pressure-sensitive adhesive surface) of the pressure-sensitive adhesive layer cured on the first surface of the substrate into contact with the peeling surface. 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 said peeling surface, the surface of a peeling liner, the base-material back surface etc. which were peel-treated can be utilized.

  Further, for example, in the case of a photocurable pressure-sensitive adhesive composition using a partially polymerized product of monomer components (acrylic polymer syrup), for example, after the pressure-sensitive adhesive composition is applied to a release surface, the applied adhesion The uncured pressure-sensitive adhesive composition is brought into contact with the first surface of the substrate by covering the first surface of the substrate with the agent composition, and in that state, between the first surface of the substrate and the peeling surface The pressure-sensitive adhesive layer may be formed by curing the pressure-sensitive adhesive composition which has been sandwiched by light irradiation.

  In addition, the method illustrated above does not limit the manufacturing method of the adhesive sheet disclosed here. In the production of 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. An example of such a method is a method of forming a pressure-sensitive adhesive layer by curing a liquid pressure-sensitive adhesive composition as described above on the first surface of the substrate, or a pressure-sensitive adhesive layer on the first surface of the substrate And the like, and a method of applying a surface treatment to enhance the throwing power of For example, when the anchorability of the pressure-sensitive adhesive layer to the substrate can be sufficiently improved by a method such as providing an undercoat layer on the first surface of the substrate, the pressure-sensitive adhesive layer after curing is used as the first surface of the substrate The pressure-sensitive adhesive sheet may be manufactured by a method of bonding to In addition, the anchorability of the pressure-sensitive adhesive layer to the substrate can be improved also by the selection of the material of the substrate and the selection of the composition of the pressure-sensitive adhesive. In addition, by applying a temperature higher than room temperature to the pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer on the first surface of the substrate, the anchorability of the pressure-sensitive adhesive layer to the substrate can be enhanced. The temperature applied to enhance anchoring may be, for example, about 35 ° C. to 80 ° C., may be about 40 ° C. to 70 ° C. or more, and may be 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 substrate, and a second pressure-sensitive adhesive layer provided on the second surface of the substrate (ie, double-sided When it is a form of adhesive substrate-attached pressure-sensitive adhesive sheet, 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 difference in structure (thickness, surface roughness, formation range, formation pattern, etc.). For example, the second pressure-sensitive adhesive layer may be a pressure-sensitive adhesive layer containing no polymer B. The surface (second adhesive surface) of the second pressure-sensitive adhesive layer 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 in contact with the release surface of the release liner. Therefore, according to this specification, a pressure-sensitive adhesive sheet (pressure-sensitive adhesive product) with a release liner is provided, which comprises any of the pressure-sensitive adhesive sheets disclosed herein and a release liner having a release surface in contact with the pressure-sensitive adhesive surface. obtain.

  The thickness of the release liner is not particularly limited, but usually about 5 μm to 200 μm is appropriate. When the thickness of the release liner is in the above range, it is preferable because the bonding workability to the pressure-sensitive adhesive layer and the peeling workability 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 known antistatic treatment such as coating type, kneading type, vapor deposition type and the like, as necessary.

  The release liner is not particularly limited, and, 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), a fluorine polymer 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 employed. It will not be specifically limited if it is a film which can protect an adhesive layer as a resin film, For example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethyl pentene film, a polyvinyl chloride film, a vinyl chloride copolymer Films, polyester films (PET films, PBT films, etc.), polyurethane films, ethylene-vinyl acetate copolymer films, etc. may be mentioned. For forming the above-mentioned release layer, for example, a silicone-based release treatment agent, a long-chain alkyl-based release treatment agent, an olefin-based release treatment agent, a fluorine-based release treatment agent, a fatty acid amide-based release treatment agent, molybdenum sulfide, silica powder, etc. And known release treatment agents can be used. The use of silicone-based release agents 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 the peeling process agent to be used can be employ | adopted suitably.

<Use>
The pressure-sensitive adhesive sheet provided by this specification, for example, has a low adhesive strength for a while in a temperature range from room temperature to about 50 ° C. (eg, 20 ° C. to 50 ° C.) after being bonded to an adherend During this period, good reworkability can be exhibited, which can contribute to the suppression of the yield and the improvement of the quality of the product including the pressure-sensitive adhesive sheet. And the said adhesive sheet can raise adhesiveness largely by aging (The heating to the temperature higher than 50 degreeC, time-lapse, these combination etc.). For example, the adhesive sheet can be firmly adhered to the adherend by heating at a desired timing. Taking advantage of such characteristics, the pressure-sensitive adhesive sheet disclosed herein is preferable in various fields for the purpose of fixing, bonding, molding, decoration, protection, reinforcement, support, shock relaxation, etc. of members included in various products. It can be used.

The pressure-sensitive adhesive sheet disclosed herein is attached to an adherend in the form of a pressure-sensitive adhesive sheet provided with a pressure-sensitive adhesive layer on at least the first surface of a film-like substrate having a first surface and a second surface. It can be preferably used as a reinforcing film for reinforcing the adherend. In such a reinforcing film, as the above-mentioned film substrate, one containing a resin film as a base film can be preferably used. Moreover, it is preferable that the said adhesive layer adheres to the 1st surface of a film-like base material from a viewpoint of improving reinforcement performance.
For example, in optical members used for optical products and electronic members used for electronic products, advanced integration, reduction in size and weight, thickness reduction are progressing, and a plurality of thin optical members having different linear expansion coefficients and thicknesses Electronic members may be stacked. Adhering the reinforcing film as described above to such a member can impart appropriate rigidity to the optical member / electronic member. Thereby, in a manufacturing process and / or a product after manufacturing, it is possible to suppress curling and bending due to stress that may occur between a plurality of members having different coefficients of linear expansion and thickness.
In addition, in the manufacturing process of optical products / electronic products, in a phase where a thin optical member / electronic member is subjected to shape processing such as cutting processing as described above, processing is performed by applying a reinforcing film to the member and processing. It is possible to relieve local stress concentration on the optical member / electronic member accompanying the problem and to reduce the risk of cracking, cracking, peeling of the laminated member, and the like. Attaching and handling the reinforcing member on the optical member / electronic member also alleviates local stress concentration during transport, lamination, rotation, etc. of the member, and also suppresses bending or bending of the member due to its own weight, etc. It can be useful.
Furthermore, devices such as optical products and electronic products containing the above-mentioned reinforcing film collided with flying objects when placed under heavy objects when the devices were dropped at the stage used by consumers in the market In the case where unintentional stress is applied in some cases, the stress applied to the device can be alleviated by including the reinforcing film in the device. Thus, the inclusion of a reinforcing film in the device can improve the durability of the device.

  In addition, the pressure-sensitive adhesive sheet disclosed herein can be preferably used, for example, in a mode of being attached to members constituting various portable devices (portable devices). Here, "portable" is not enough to be only portable, but means that an individual (a standard adult) has a portability that is relatively easy to carry. Do. In addition, examples of mobile devices here include mobile phones, smartphones, tablet computers, laptop computers, various wearable devices, digital cameras, digital video cameras, audio devices (portable music players, IC recorders, etc.), calculators (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 scanners, portable modems, etc. Clocks, flashlights, hand mirrors etc. may be included. Examples of members constituting the portable electronic device may include an optical film, a display panel and the like used in an image display device such as a thin layer display such as a liquid crystal display and a film type display. The pressure-sensitive adhesive sheet disclosed herein can also be preferably used in a mode in which the pressure-sensitive adhesive sheet is attached to various members in automobiles, home appliances, and the like.

The matters disclosed by this specification include the following.
(1) A pressure-sensitive adhesive sheet containing a pressure-sensitive adhesive layer,
The pressure-sensitive adhesive layer contains a polymer A, and a polymer B which 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 of 50 ° C. or more and 100 ° C. or less based on the composition of the (meth) acrylic monomer,
Adhesiveness N ₈₀ after heating for 5 minutes at 80 ° C after bonding to stainless steel plates is 5 times or more of adhesion N ₅₀ after holding for 30 minutes at 50 ° C after bonding to stainless steel plates Sheet.
(2) The relationship between the adhesive strength N ₅₀ and the adhesive strength N ₂₃ after holding on a stainless steel plate for 30 minutes after bonding to a stainless steel plate is the following formula:
(N ₅₀ / N ₂₃ ) <10;
The adhesive sheet as described in said (1) which satisfy | fills.
(3) The adhesive sheet according to the above (1) or (2), wherein the adhesive strength N ₈₀ is 10 times or more of the adhesive strength N ₂₃ after leaving on a stainless steel plate and left at 23 ° C. for 30 minutes. .
(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] have the following relational expressions:
(N ₈₀ -N ₅₀ ) / (N ₅₀ -N ₂₃ ) ≧ 2;
The adhesive sheet in any one of said (1)-(3) which satisfy | fills.
(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 sheet in any one of said (1)-(6) whose said adhesive force N ₈₀ is 15 N / 25 mm or more.

(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 the above (1) to (9), wherein the polymer B has a copolymerization ratio of 30% by weight or less of a monomer whose glass transition temperature of homopolymer is higher than 170 ° C.
(11) The pressure-sensitive adhesive sheet according to any one of (1) to (10), wherein the pressure-sensitive adhesive layer contains more than 0 parts by weight and 10 parts by weight or less of a crosslinking agent based on 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 10000 or more and 50000 or less.
(13) The content of the polymer B in the pressure-sensitive adhesive layer is 0.05 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the polymer A according to any one of the above (1) to (12) Adhesive sheet.

(14) The adhesive sheet in any one of said (1)-(13) whose said polymer A is an acryl-type polymer.
(15) The adhesive sheet as described in said (14) in which the monomer component for preparing the said acryl-type polymer contains a hydroxyl-containing monomer.
(16) The adhesive sheet as described in said (14) in which the monomer component for preparing the said acryl-type polymer contains N-vinyl cyclic amide and a hydroxyl-containing monomer.
(17) The adhesive sheet in any one of said (1)-(16) in which the said adhesive layer contains an isocyanate type crosslinking agent.
(18) The pressure-sensitive adhesive sheet according to any one of the above (1) to (17), wherein the monomer component for preparing the polymer B contains methyl methacrylate (MMA).
(19) The pressure-sensitive adhesive sheet according to (18), wherein the ratio of MMA to 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 adhesive sheet in any one of said (1)-(19) whose thickness of the said adhesive layer is 3 micrometers or more and 100 micrometers or less (for example, 20 micrometers or more and 50 micrometers or less).

(21) Any one of the above (1) to (20), comprising a support base having a first side and a second side, wherein the pressure-sensitive adhesive layer is laminated on at least the first side of the support base Adhesive sheet as described in.
(22) The adhesive sheet as described in said (21) whose thickness of the said support base material is 30 micrometers or more.
(23) The pressure-sensitive adhesive sheet according to (21) or (22), wherein the thickness of the supporting substrate is 1.1 times or more and 10 times or less the thickness of the pressure-sensitive adhesive layer.
(24) The pressure-sensitive adhesive sheet according to any one of the above (21) to (23), wherein the support substrate contains 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 (eg, 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 supporting substrate.
(27) The pressure-sensitive adhesive sheet according to any one of the above (21) to (26), which is attached to an adherend and used to reinforce the adherend.
(28) The pressure-sensitive adhesive sheet according to any one of the above (1) to (27), wherein the surface (pressure-sensitive adhesive surface) of the pressure-sensitive adhesive layer is in contact with a releasable surface having a water contact angle of 100 degrees or more.

(29) A pressure-sensitive adhesive sheet according to any one of the above (1) to (28), and a release liner having a release surface that comes 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 release surface is 100 degrees or more.
(30) The release liner-attached pressure-sensitive adhesive sheet according to (29), wherein the release surface is a surface of a release layer formed by a silicone release treatment agent.

  The following examples illustrate some of the embodiments of the present invention, but are not intended to limit the present invention to those shown in the specific examples. In the following description, "parts" and "%" are on a weight basis unless otherwise noted.

(Preparation of Polymer A1)
In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet and condenser, 60 parts of 2EHA, 15 parts of N-vinyl-2-pyrrolidone (NVP), 10 parts of methyl methacrylate (MMA), 2-hydroxyethyl Charge 15 parts of Acrylate (HEA) and 200 parts of ethyl acetate as a polymerization solvent, stir at 60 ° C under nitrogen atmosphere for 2 hours, then charge 0.2 parts of AIBN as a thermal polymerization initiator, 6 hours at 60 ° C The reaction was carried out to obtain a solution of polymer A1. Mw of this polymer A1 was 1.1 million.

(Preparation of Polymer B1)
100 parts of toluene, 40 parts of MMA, 20 parts of n-butyl methacrylate (BMA), 2-ethylhexyl methacrylate (2EHMA) 20 in a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet pipe, condenser and dropping funnel The polyorganosiloxane skeleton-containing methacrylate monomer (trade name: X-22-174 ASX, manufactured by Shin-Etsu Chemical Co., Ltd.) having a functional group equivalent of 900 g / mol, and a 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 thioglycollate as a chain transfer agent were charged. After stirring at 70 ° C. under a nitrogen atmosphere for 1 hour, 0.2 parts of AIBN is added as a thermal polymerization initiator, and after reacting for 2 hours at 70 ° C., 0.1 parts by weight of AIBN as a thermal polymerization initiator After charging, it was allowed to react at 80 ° C. for 5 hours. Thus, a solution of polymer B1 was obtained. Mw of this polymer B1 was 22000.

(Preparation of Polymers B2 to B7)
The composition of the monomer component was changed as shown in Table 1, Polymer B2 was prepared in the same manner as in the preparation of Polymer B1, except that 0.8 parts of thioglycerol was used as a chain transfer agent and ethyl acetate was used as a polymerization solvent. B7 was prepared. The 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 Shown together.

In addition, the weight average molecular weight of each polymer mentioned above was measured on condition of the following using GPC apparatus (made by Tosoh Corp., HLC-8220GPC), and it 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 ° C
·column:
Sample column; TSKguardcolumn SuperHZ-H (one) + TSKgel SuperHZM-H (two)
Reference column; TSKgel SuperH-RC (one)
・ 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, it was used -127 ° C. as the value of the KF-2012 of Tg. The Tg of the polyorganosiloxane skeleton-containing methacrylate monomer is determined by placing the monomer (measurement sample) in a simple aluminum closed container and performing DSC (differential scanning calorimetry) under the following conditions.
[DSC condition]
Device: TA Instruments, Q-2000
Temperature program: -160 ° C to 40 ° C
Heating rate: 10 ° C / min
Atmosphere gas: He (50 ml / min)

<Production of adhesive sheet>
(Example 1)
In the solution of the polymer A1, 2.5 parts of the polymer B1 per 100 parts of the polymer A1 contained in the solution, an isocyanate crosslinking agent (trade name: Takenate D110N, trimethylolpropane xylylene diisocyanate, manufactured by Mitsui Chemicals, Inc.) 2.5 parts were added and uniformly mixed to prepare a pressure-sensitive adhesive composition C1.
Adhesive composition C1 is 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, and dried by heating at 110 ° C for 2 minutes As a result, a 25 .mu.m-thick pressure-sensitive adhesive layer was formed. The release surface of the release liner R1 was attached to the surface (adhesive surface) of the pressure-sensitive adhesive layer. Thus, a pressure-sensitive adhesive sheet according to Example 1 was obtained in the form of a release-lined pressure-sensitive adhesive sheet in which the pressure-sensitive adhesive surface was in contact with the release surface of the release liner.
As a release liner, MRQ 25T100 (a release liner having a release layer with a silicone release treating agent on one side of a polyester film, 25 μm in thickness) manufactured by Mitsubishi Chemical Corporation was used.

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

<Measurement of adhesion to SUS>
The adhesive sheet according to each example is cut into 25 mm width together with a release liner as a test piece, and a toluene-cleaned SUS plate (SUS304BA plate) is used as an adherend in the following procedures: adhesive strength N ₂₃ , adhesive strength N ₅₀ and tack N ₈₀ were measured.
(Measurement of adhesive strength N ₂₃ )
Under 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 crimped to the adherend by one reciprocation of a 2 kg roller. After leaving the test pieces pressure-bonded to the adherend in this way for 30 minutes under the above standard environment, using a universal tensile compression tester (apparatus name "tensile compression tester, TCM-1kNB" manufactured by Minebea Co., Ltd.) In accordance with JIS Z 0237, the 180 ° peel strength (resistance to the above-mentioned tension) was measured at a peeling angle of 180 ° and a tensile speed of 300 mm / min. The measurement was performed three times, and their average value is shown in Table 2 as adhesive strength (N ₂₃ ) [N / 25 mm] after 30 minutes at 23 ° C.
(Measurement of adhesive strength N ₅₀ )
The test piece pressure-bonded to the adherend in the same manner as in the measurement of the adhesive strength ₂₃ is held in an environment of 50 ° C. for 30 minutes, and then left in the standard environment for 30 minutes. Was measured. The measurement was performed three times, and their average value is shown in Table 2 as adhesion (N ₅₀ ) [N / 25 mm] after 50 ° C. 30 minutes.
(Measurement of adhesive strength N ₈₀ )
The test piece pressure-bonded to the adherend in the same manner as in the measurement of the adhesive strength ₂₃ is heated at 80 ° C. for 5 minutes and then left under the above standard environment for 30 minutes. did. The measurement was carried out three times, and their average value is shown in Table 2 as adhesion (N ₈₀ ) [N / 25 mm] after 80 ° C. for 5 minutes. 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 measurement results, 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 adhesive sheets of Examples 5 to 9 using polymers B3 to B5 having glass transition temperatures T _{m1 in} the range of 50 ° C. to 100 ° C. have N ₈₀ / N ₅₀ of 5 or more. Thus, it was confirmed that even if a temperature of about 50 ° C. is added to the initial stage of application, the low adhesiveness suitable for rework can be maintained, and the adhesive strength can 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 the polymers B1, B2 and B7 having a glass transition temperature T _m1 lower than 50 ° C. have an N ₈₀ / N ₅₀ of less than 5 and about 50 ° C. at the initial stage of application The adhesion was likely to be increased by the addition of the above temperature. In the pressure-sensitive adhesive sheet of Example 4, N ₅₀ was relatively low, but heating at 80 ° C. for 5 minutes could not significantly increase the adhesion. Further, in Example 10 in which the glass transition temperature T _m1 exceeded 100 ° C. and the polymer B6 was used, the adhesion could not be increased by heating at 80 ° C. for 5 minutes.

  As mentioned above, although the specific example of this invention was described in detail, these are only an illustration and do not limit a claim. The art set forth in the claims includes various variations and modifications 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 side (1st adhesive side)
21B adhesive side (second adhesive side)
22 Pressure-sensitive adhesive layer (second pressure-sensitive adhesive layer)
22A adhesive side (second adhesive side)
31, 32 Release Liner 100, 200, 300 Adhesive Sheet with Release Liner (Adhesive Products)

Claims (10)

A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer,
The pressure-sensitive adhesive layer contains a polymer A, and a polymer B which 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,
Adhesiveness N ₈₀ after heating for 5 minutes at 80 ° C after bonding to stainless steel plates is 5 times or more of adhesion N ₅₀ after holding for 30 minutes at 50 ° C after bonding to stainless steel plates 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 adhesive sheet of Claim 1 which satisfy | fills. The polymer glass transition temperature T _A of A is less than -80 ° C. or higher 0 ° 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 sheet according to any one of claims 1 to 4, wherein the polymer B has a copolymerization ratio of a monomer having a homopolymer whose glass transition temperature is higher than 170 ° C and which is 30% by weight or less.   The pressure-sensitive adhesive sheet according to any one of claims 1 to 5, wherein the pressure-sensitive adhesive layer contains more than 0 parts by weight and 10 parts by weight or less of a crosslinking agent with respect to 100 parts by weight of the polymer A.   The pressure-sensitive adhesive sheet according to any one of claims 1 to 6, wherein the polymer B has a weight average molecular weight of 10000 or more and 50000 or less.   The pressure-sensitive adhesive sheet according to any one of claims 1 to 7, wherein a content of the polymer B in the pressure-sensitive adhesive layer is 0.05 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of the polymer A.   The adhesion according to any one of claims 1 to 8, comprising a support base having a first side and a second side, wherein the pressure-sensitive adhesive layer is laminated on at least the first side of the support base. Sheet.   The pressure-sensitive adhesive sheet according to claim 9, wherein the thickness of the support substrate is 30 μm or more.

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