CN106255733B

CN106255733B - Adhesive sheet and optical member

Info

Publication number: CN106255733B
Application number: CN201580019596.2A
Authority: CN
Inventors: 片冈贤一; 天野立巳
Original assignee: Nitto Denko Corp
Current assignee: Nitto Denko Corp
Priority date: 2014-04-16
Filing date: 2015-04-03
Publication date: 2020-09-08
Anticipated expiration: 2035-04-03
Also published as: WO2015159738A1; KR102290158B1; TW201546234A; TWI708824B; JP2015212362A; KR20160148580A; JP6594637B2; CN106255733A

Abstract

The invention provides an adhesive sheet which can prevent the increase of adhesive force (adhesive force increase preventing property and adhesive force stability) under high speed time, restrain the adhesive force to be low when stripping at high speed, and has excellent re-stripping property and operation property and excellent shearing force. The adhesive sheet of the present invention is an adhesive sheet having an adhesive layer formed from an adhesive composition on one or both surfaces of a support film, wherein the adhesive ratio (B/A) between the adhesive force (A) at a peeling speed of 30 m/min after the adhesive surface of the adhesive layer is attached to the TAC surface at 23 ℃ for 30 minutes and the adhesive force (B) at a peeling speed of 30 m/min after the adhesive surface of the adhesive layer is attached to the TAC surface at 70 ℃ for 1 week is less than 2.

Description

Adhesive sheet and optical member

Technical Field

The present invention relates to an adhesive sheet and an optical member protected by the adhesive sheet.

The adhesive sheet of the present invention is useful as a surface protective film for protecting the surface of an optical member used in a liquid crystal display or the like, such as a polarizing plate, a wavelength plate, a retardation plate, an optical compensation film, a reflection sheet, a luminance enhancement film, or the like.

Background

In recent years, when transporting optical components and electronic components or mounting the components on a printed circuit board, the components are transported in a state of being packaged in a predetermined sheet or in a state of being attached with an adhesive tape. Among them, the surface protective film is widely used particularly in the fields of optics and electronic parts.

A surface protection film is generally bonded to an adherend (protected object) via an adhesive applied to a support film side, and is used for the purpose of preventing damage and dirt generated during processing and transportation of the adherend (patent document 1). For example, a panel of a liquid crystal display is formed by bonding optical members such as a polarizing plate and a wavelength plate to a liquid crystal cell via an adhesive. The surface protective film is bonded to these optical members via an adhesive, and can prevent damage and dirt from occurring during processing and transportation of an adherend.

In addition, when processing an adherend in a state where a surface protective film is bonded thereto, high-temperature processing may be performed, but in such a case, the adhesive force of the adhesive agent layer may greatly increase, and when peeling and removing are performed at a stage where the surface protective film becomes unnecessary, damage to a polarizing plate or a liquid crystal cell as the adherend is likely to occur in a peeling step along with an increase in size and thinning of a liquid crystal display panel or the like as the adherend, and therefore, light peeling is required at high-speed peeling after high-temperature processing.

The surface protective film is required to have curl adjustability so that when the surface protective film is attached to an adherend (a polarizing plate or the like), unnecessary curl or undesirable curl (curl means a curling phenomenon, for example, a curling phenomenon in which either side of a flat plate-shaped object is entirely curled, a curling phenomenon in which the flat plate-shaped object is entirely undulated, or the like) does not occur in the adherend (a polarizing plate or the like) to which the surface protective film is attached. If unnecessary curl or undesirable curl is generated, the handling property is poor, and for example, when an adherend such as a polarizing plate is stuck to a liquid crystal cell, there may be a problem such as intrusion of air bubbles.

In addition, when a flat plate-shaped adherend is curled, a force accompanying the curling acts in a shear direction in an adhesive layer of a surface protective film attached to the adherend, and a slip, a misalignment, or the like gradually occurs between the adherend and the adhesive layer due to the force, and therefore, it is required to increase a shear force at the time of low-speed peeling.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 9-165460

Disclosure of Invention

Technical problem to be solved by the invention

Accordingly, an object of the present invention is to solve the problems of the conventional adhesive sheet and to provide an adhesive sheet which can prevent the increase of the adhesive force with time at high temperature (the property of preventing the increase of the adhesive force and the stability of the adhesive force), reduce the adhesive force at the time of high-speed peeling, and is excellent in removability and workability and excellent in the shear force.

Means for solving the problems

That is, the adhesive sheet of the present invention is an adhesive sheet having an adhesive layer formed of an adhesive composition on one surface or both surfaces of a support film, wherein the adhesive ratio (B/a) of the adhesive force (a) at a peeling speed of 30 m/min after the adhesive surface of the adhesive layer is attached to the TAC surface at 23 ℃ for 30 minutes to the adhesive force (B) at a peeling speed of 30 m/min after the adhesive surface of the adhesive layer is attached to the TAC surface at 70 ℃ for 1 week is less than 2.

The adhesive sheet of the present invention is preferably: the adhesive composition contains a (meth) acrylic polymer having a hydroxyl group and a carboxyl group.

The adhesive sheet of the present invention is preferably: the adhesive composition contains a crosslinking agent, and the crosslinking agent contains an aromatic isocyanate compound and an aliphatic isocyanate compound.

The adhesive sheet of the present invention is preferably: the hydroxyl group-containing (meth) acrylic monomer is contained in an amount of 5.1 mass% or more based on the total amount of monomer components constituting the (meth) acrylic polymer.

The adhesive sheet of the present invention is preferably: the carboxyl group-containing (meth) acrylic monomer is contained in an amount of 0.01 mass% or more and less than 0.5 mass% based on the total amount of the monomer components constituting the (meth) acrylic polymer.

The adhesive sheet of the present invention is preferably: the antistatic layer is formed of an antistatic agent composition containing polyaminobenzene sulfonic acid as a conductive polymer component, a polyester resin as a binder, and an isocyanate-based crosslinking agent as a crosslinking agent.

The adhesive sheet of the present invention is preferably: the antistatic agent composition further contains a fatty acid amide as a lubricant.

The optical member of the present invention is preferably an optical member protected by the adhesive sheet.

Effects of the invention

The pressure-sensitive adhesive sheet of the present invention can prevent an increase in adhesive force over time at high temperatures (an increase preventing property of adhesive force, stability of adhesive force), reduce adhesive force at the time of high-speed peeling, and is excellent in removability and workability, and further excellent in shear force, and therefore can suppress unnecessary curling or undesirable curling in an adherend when it is bonded to the adherend, and is useful.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail.

< integral Structure of adhesive sheet (surface protective film) >

The adhesive sheet (surface protection film) of the present invention is generally referred to as an adhesive sheet, an adhesive tape, an adhesive label, an adhesive film, or the like, and is particularly suitable as a surface protection film for protecting the surface of an optical member (for example, an optical member used as a constituent element of a liquid crystal display panel such as a polarizing plate or a wavelength plate) during processing and transportation of the optical member. The adhesive layer in the adhesive sheet is typically formed continuously, but is not limited to the above form, and may be formed in a regular or random pattern such as dots or stripes, for example. The adhesive sheet disclosed herein may be in the form of a roll or a sheet.

Typical examples of the adhesive sheet (surface protective film) disclosed herein include an adhesive sheet having an adhesive layer on one or both surfaces of a support film (substrate), and an adhesive sheet having an antistatic layer provided on one surface of the support film and an adhesive layer provided on the surface opposite to the antistatic layer of the support film. The adhesive sheet is used by attaching the adhesive layer to an adherend (a surface of an optical member to be protected, for example, a polarizing plate). The pressure-sensitive adhesive sheet before use (i.e., before attachment to an adherend) may be in the following form: the surface of the adhesive layer (the surface to be adhered to an adherend) is protected by a release liner having a release surface on at least the adhesive layer side. Alternatively, the adhesive sheet may be in the form of: when the adhesive layer is wound in a roll shape, the adhesive layer comes into contact with the back surface (the surface of the antistatic layer) of the support film, and the surface thereof is protected.

< supporting film >

The adhesive sheet of the present invention is characterized in that the adhesive sheet has an adhesive layer made of an adhesive composition on one side or both sides of a support film. The resin material constituting the support film may be used without particular limitation, and for example, a material excellent in characteristics such as transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, flexibility, and dimensional stability is preferably used. In particular, the support film is flexible, and therefore, the adhesive composition can be applied by a roll coater or the like, and can be wound into a roll form, which is useful.

As the support film (substrate), for example, polyester polymers such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate; cellulose polymers such as diacetylcellulose and triacetylcellulose; a polycarbonate-series polymer; a plastic film made of a resin material containing an acrylic polymer such as polymethyl methacrylate as a main resin component (a main component in the resin component, typically 50 mass% or more) is used as the support film. Other examples of the resin material include: styrene polymers such as polystyrene and acrylonitrile-styrene copolymer; olefin polymers such as polyethylene, polypropylene, polyolefins having a cyclic or norbornene structure, and ethylene-propylene copolymers; a vinyl chloride polymer; polyamide polymers such as nylon 6, nylon 66 and aromatic polyamide are used as the resin material. Still other examples of the resin material include: imide polymers, sulfone polymers, polyether ether ketone polymers, polyphenylene sulfide polymers, vinyl alcohol polymers, vinylidene chloride polymers, vinyl butyral polymers, arylate polymers, polyoxymethylene polymers, epoxy polymers, and the like. The support film may be a mixture of 2 or more of the above polymers.

As the support film, a plastic film formed of a transparent thermoplastic resin material can be preferably used. Among the plastic films, a polyester film is more preferably used. Here, the polyester film is a film containing, as a main resin component, a polymer material (polyester resin) having a main skeleton based on an ester bond, such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polybutylene terephthalate. The polyester film has characteristics preferable as a support film of an adhesive sheet, such as excellent optical characteristics and dimensional stability, and has a property of being easily charged.

Various additives such as an antioxidant, an ultraviolet absorber, a plasticizer, a colorant (such as a pigment and a dye) may be blended as necessary with the resin material constituting the support film. The first surface (the surface on which the antistatic layer is provided) of the support film may be subjected to a known or conventional surface treatment such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, and coating with a primer. Such a surface treatment may be, for example, a treatment for improving adhesion between the support film and the antistatic layer. It is preferable to use a surface treatment for introducing a polar group such as a hydroxyl group (-OH group) into the surface of the support film. The second surface (the surface on the side where the adhesive layer is formed) of the support film may be subjected to the same surface treatment as described above. The surface treatment may be a treatment for improving the adhesion between the film and the adhesive layer (the anchoring property of the adhesive layer).

In the case where the pressure-sensitive adhesive sheet of the present invention has an antistatic layer on a support film and an antistatic function, a plastic film further subjected to antistatic treatment may be used as the support film. The use of the support film is preferable because the electrification of the pressure-sensitive adhesive sheet itself after peeling can be suppressed. The support film is a plastic film, and the plastic film is subjected to antistatic treatment, whereby an adhesive sheet having reduced electrification of the adhesive sheet itself and excellent antistatic ability against an adherend can be obtained. Here, the method of imparting the antistatic function is not particularly limited, and conventionally known methods can be used, and examples thereof include: a method of coating an antistatic resin comprising an antistatic agent and a resin component, a method of coating a conductive resin comprising a conductive polymer and a conductive substance, a method of vapor deposition or plating of a conductive substance, and a method of incorporating an antistatic agent or the like.

The thickness of the support film is usually 5 to 200 μm, preferably about 10 to 100 μm. When the thickness of the support film is within the above range, workability of bonding to an adherend and workability of peeling from an adherend are excellent, and therefore, the support film is preferable.

< adhesive composition >

The adhesive sheet (surface protective film) of the present invention has the adhesive layer, the adhesive layer is a layer formed of an adhesive composition, and the adhesive composition can be used without particular limitation as long as it has adhesiveness, and for example, an acrylic adhesive, a urethane adhesive, a synthetic rubber adhesive, a natural rubber adhesive, a silicone adhesive, and the like are used.

The adhesive composition used in the present invention preferably contains a (meth) acrylic polymer having a hydroxyl group and a carboxyl group. By using the (meth) acrylic polymer having a hydroxyl group and a carboxyl group, the hydroxyl group can be easily controlled to be crosslinked, and the carboxyl group can increase a shear force or prevent an increase in adhesive force with time, which is a preferable embodiment. Since the shear force of the pressure-sensitive adhesive (layer) is increased, the pressure-sensitive adhesive is bonded to an adherend, whereby curling of the adherend can be suppressed, and occurrence of sliding or misalignment between the pressure-sensitive adhesive and the adherend (interface) can be suppressed, which is particularly preferable. In the present invention, the (meth) acrylic polymer means an acrylic polymer and/or a methacrylic polymer, and the (meth) acrylate means an acrylate and/or a methacrylate.

Further, by using the hydroxyl group-containing (meth) acrylic monomer as a monomer component, the (meth) acrylic polymer can easily control crosslinking of the adhesive composition, and can easily control the balance between the improvement of wettability by flow and the cohesive force of the adhesive (layer), the reduction of adhesive force at the time of peeling (light peeling property), and the shear force. Further, when an antistatic agent is added to the pressure-sensitive adhesive, unlike a carboxyl group, a sulfonate group, or the like which generally functions as a crosslinking site, a hydroxyl group has a moderate interaction with an ionic compound or the like which is an antistatic agent, and therefore, the pressure-sensitive adhesive can be suitably used even in terms of antistatic properties.

The adhesive sheet of the present invention is preferably: the hydroxyl group-containing (meth) acrylic monomer is contained in an amount of 5.1% by mass or more, more preferably 5.3 to 15% by mass, and still more preferably 7 to 12% by mass, based on the total amount of the monomer components constituting the (meth) acrylic polymer. When the content is within the above range, the balance between the wettability of the adhesive composition and the cohesive force and shear force of the adhesive (layer) can be easily controlled, and therefore, the content is preferable.

Examples of the hydroxyl group-containing (meth) acrylic monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, 4-hydroxymethylcyclohexyl (4-hydroxymethylcyclohexyl) methyl acrylate, and N-methylol (meth) acrylamide.

The adhesive sheet of the present invention is preferably: the carboxyl group-containing (meth) acrylic monomer is contained in an amount of 0.01 mass% or more and less than 0.5 mass%, more preferably 0.01 mass% or more and less than 0.4 mass%, still more preferably 0.01 mass% or more and less than 0.3 mass%, and most preferably 0.01 mass% or more and less than 0.2 mass%, based on the total amount of the monomer components constituting the (meth) acrylic polymer. When the amount is within the above range, the increase in the adhesive strength with time can be suppressed, and the removability, the prevention of the increase in the adhesive strength, and the workability are excellent. In addition, not only the adhesive layer has excellent cohesive force, but also excellent shear force, is preferred. Here, if there are many acid functional groups such as carboxyl groups having a large polar action, when an ionic compound as an antistatic agent is blended, the acid functional groups such as carboxyl groups and the like interact with the ionic compound, thereby inhibiting ion conduction, lowering the conductive efficiency, and possibly failing to obtain sufficient antistatic properties, which is not preferable.

Examples of the carboxyl group-containing (meth) acrylic monomer include: (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, 2- (meth) acryloyloxyethylhexahydrophthalic acid, 2- (meth) acryloyloxypropylhexahydrophthalic acid, 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxyethylsuccinic acid, 2- (meth) acryloyloxyethylmaleic acid, carboxypolycaprolactone mono (meth) acrylate, 2- (meth) acryloyloxyethyltetrahydrophthalic acid, and the like.

The adhesive composition used in the present invention contains the (meth) acrylic polymer, and is not particularly limited as long as it is a (meth) acrylic polymer having adhesiveness, and as a main component of the monomer component, a (meth) acrylic monomer having an alkyl group with 1 to 14 carbon atoms is preferably used, and a (meth) acrylic monomer having an alkyl group with 4 to 14 carbon atoms is more preferably used. As the (meth) acrylic monomer, 1 or 2 or more species may be used as a main component. Here, the term "main component" means that the mixing ratio is the highest.

Specific examples of the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, and n-tetradecyl (meth) acrylate.

When the pressure-sensitive adhesive sheet of the present invention is used as a surface protective film, examples of suitable monomers include (meth) acrylates having an alkyl group having 6 to 14 carbon atoms, such as hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, and n-tetradecyl (meth) acrylate. By using a (meth) acrylate having an alkyl group having 6 to 14 carbon atoms, the adhesion to an adherend can be easily controlled to be low, and the removability is excellent.

The adhesive sheet of the present invention is preferably: the (meth) acrylic monomer having an alkyl group with 1 to 14 carbon atoms is contained in an amount of 50 to 94.99% by mass, more preferably 60 to 94.9% by mass, still more preferably 70 to 94.8% by mass, and most preferably 80 to 94.7% by mass, based on the total amount of monomer components constituting the (meth) acrylic polymer. When the content is within the above range, the adhesive composition has appropriate wettability and the adhesive (layer) is excellent in cohesive force, which is preferable.

Further, as the other polymerizable monomer component, for the reason that the balance of the adhesive properties is easily obtained, a polymerizable monomer for adjusting the glass transition temperature and the releasability of the (meth) acrylic polymer may be used so that the Tg becomes 0 ℃ or lower (usually-100 ℃ or higher) within the range not to impair the effect of the present invention.

The polymerizable monomer other than the hydroxyl group-containing (meth) acrylic monomer, the carboxyl group-containing (meth) acrylic monomer, and the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms used in the (meth) acrylic polymer is not particularly limited as long as the characteristics of the present invention are not impaired. For example, a component for improving cohesive force and heat resistance such as a cyano group-containing monomer, a vinyl ester monomer, or an aromatic vinyl monomer, a component for improving adhesion (bonding) force or having a functional group which functions as a crosslinking base point such as an amide group-containing monomer, an imide group-containing monomer, an amino group-containing monomer, an epoxy group-containing monomer, N-acryloylmorpholine, or a vinyl ether monomer, can be suitably used. These polymerizable monomers may be used alone, or 2 or more kinds may be mixed and used.

Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile.

Examples of the vinyl ester monomer include vinyl acetate, vinyl propionate, and vinyl laurate.

Examples of the aromatic vinyl monomer include styrene, chlorostyrene, chloromethylstyrene, α -methylstyrene, and other substituted styrenes.

Examples of the amide group-containing monomer include acrylamide, methacrylamide, diethylacrylamide, N-vinylpyrrolidone, N-dimethylacrylamide, N-dimethylmethacrylamide, N-diethylacrylamide, N-diethylmethacrylamide, N' -methylenebisacrylamide, N-dimethylaminopropylacrylamide, N-dimethylaminopropylmethacrylamide, diacetoneacrylamide, and the like.

Examples of the imide group-containing monomer include cyclohexylmaleimide, isopropylmaleimide, N-cyclohexylmaleimide, and itaconimide.

Examples of the amino group-containing monomer include aminoethyl (meth) acrylate, N-dimethylaminoethyl (meth) acrylate, and N, N-dimethylaminopropyl (meth) acrylate.

Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate, methylglycidyl (meth) acrylate, and allyl glycidyl ether.

Examples of the vinyl ether monomer include methyl vinyl ether, ethyl vinyl ether, and isobutyl vinyl ether.

In the present invention, the polymerizable monomer other than the carboxyl group-containing (meth) acrylic monomer, the hydroxyl group-containing (meth) acrylic monomer, and the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms is preferably 0 to 40% by mass, more preferably 0 to 30% by mass, of the total amount of monomer components (all monomer components) constituting the (meth) acrylic polymer. By using the other polymerizable monomer within the above range, good interaction with the ionic compound used as the antistatic agent and good removability can be appropriately adjusted.

The weight average molecular weight of the (meth) acrylic polymer is 10 to 500 ten thousand, preferably 20 to 400 ten thousand, and more preferably 30 to 300 ten thousand. When the weight average molecular weight is less than 10 ten thousand, the cohesive force of the obtained adhesive (layer) becomes small, and thus residual glue tends to be generated. On the other hand, when the weight average molecular weight exceeds 500 ten thousand, the fluidity of the polymer decreases, the wetting with an adherend (for example, a polarizing plate as an optical member or the like) becomes insufficient, and foaming tends to occur between the adherend and the pressure-sensitive adhesive composition layer of the pressure-sensitive adhesive sheet. Here, the weight average molecular weight is measured by GPC (gel permeation chromatography).

The glass transition temperature (Tg) of the (meth) acrylic polymer is preferably 0 ℃ or lower, more preferably-10 ℃ or lower, and still more preferably-20 ℃ or lower (usually-100 ℃ or higher). When the glass transition temperature is higher than 0 ℃, the polymer is difficult to flow, and for example, wetting of an adherend (for example, a polarizing plate or the like as an optical member) becomes insufficient, and there is a tendency that the polymer causes foaming between the adherend and the adhesive composition layer of the adhesive sheet. In particular, by setting the glass transition temperature to-61 ℃ or lower, an adhesive composition excellent in wettability to an adherend and light peelability can be easily obtained. Here, the glass transition temperature of the (meth) acrylic polymer can be adjusted within the above range by appropriately changing the monomer components and the composition ratio used.

The method for polymerizing the (meth) acrylic polymer used in the present invention is not particularly limited, and polymerization can be carried out by a known method such as solution polymerization, emulsion polymerization, bulk polymerization, or suspension polymerization, and particularly, solution polymerization is a more preferable mode from the viewpoint of workability and properties such as low staining property to an adherend. The polymer obtained may be a random copolymer, a block copolymer, an alternating copolymer, a graft copolymer, or the like.

The pressure-sensitive adhesive sheet of the present invention may contain an antistatic agent (antistatic component), and the antistatic agent may contain an ionic compound. Examples of the ionic compound include an alkali metal salt and/or an ionic compound having a low melting point (melting point of 150 ℃ or lower). By containing these ionic compounds, excellent antistatic properties can be imparted.

The content of the ionic compound is preferably 1 part by mass or less, more preferably 0.001 to 0.9 part by mass, and still more preferably 0.005 to 0.8 part by mass, based on 100 parts by mass of the (meth) acrylic polymer. Within the above range, both antistatic properties and low staining properties are easily achieved, and therefore, the range is preferable.

In the case of the adhesive sheet of the present invention, the adhesive composition may contain an organopolysiloxane having a polyoxyalkylene chain. It is presumed that by using the organopolysiloxane, the surface free energy of the adhesive surface is reduced and the peeling is made light at the time of high-speed peeling.

As the organopolysiloxane, known organopolysiloxanes having a polyoxyalkylene chain can be suitably used, and examples of commercially available products include those having a trade name of X-22-4952, X-22-4272, X-22-6266, KF-6004, KF-889, KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-6022, X-22-6191, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017, X-22-2516 (manufactured BY shin-Etsu chemical industries Co., Ltd.), BY16-201, SF8427, SF8428, FZ-2162, SH3749, FZ-77, L-7001, L-b, Examples of the material include FZ-2104, FZ-2110, L-7002, FZ-2122, FZ-2164, FZ-2203, FZ-7001, SH8400, SH8700, SF8410, SF8422 (manufactured by Tourette Corning Co., Ltd.), IM22 (manufactured by Asahi Kawakker Co., Ltd.), TSF-4440, TSF-4441, TSF-4445, TSF-4450, TSF-4446, TSF-4452, TSF-4460 (manufactured by Michigan Hi-Tech materials Co., Ltd.), BYK-333, BYK-307, BYK-377, BYK-UV3500 and BYK-UV3570 (manufactured by Pic Nippon Co., Ltd.). These may be used alone, or 2 or more of them may be used in combination.

The organopolysiloxane used in the present invention preferably has an HLB (hydrophilic-lipophilic balance) value of 1 to 16, more preferably 3 to 14. If the HLB value is outside the above range, the staining property to an adherend is deteriorated, which is not suitable.

The content of the organopolysiloxane is preferably 0.01 to 5 parts by mass, more preferably 0.03 to 3 parts by mass, and still more preferably 0.05 to 1 part by mass, per 100 parts by mass of the (meth) acrylic polymer. When the content is within the above range, both antistatic property and light peelability (removability) are easily achieved, and therefore, the content is preferable.

In the adhesive sheet of the present invention, the adhesive composition preferably contains a crosslinking agent, and the crosslinking agent preferably contains an aromatic isocyanate compound and an aliphatic isocyanate compound (in some cases, the combination of two isocyanate compounds is referred to as an isocyanate compound or an isocyanate crosslinking agent). In addition, the crosslinking agent can be crosslinked by appropriately adjusting the selection and addition ratio of the crosslinking agent according to the constituent unit, the constituent ratio, and the like of the (meth) acrylic polymer, and thus an adhesive sheet (adhesive layer) having more excellent heat resistance can be obtained. The crosslinking agent is useful in that it contains an aromatic isocyanate compound and an aliphatic isocyanate compound, and thus can prevent the increase of the adhesive force with time (adhesion force increase preventing property).

In addition, as the crosslinking agent used in the present invention, in addition to the aromatic isocyanate compound and the aliphatic isocyanate compound, an epoxy compound, a melamine resin, an aziridine derivative, a metal chelate compound, and the like can be suitably used. These compounds may be used alone in 1 kind, or 2 or more kinds may be used in combination.

Examples of the aliphatic isocyanate compound include aliphatic polyisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, Hexamethylene Diisocyanate (HDI), and dimer acid diisocyanate, and alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate (IPDI). Examples of the aromatic isocyanate compound include aromatic isocyanates such as 2, 4-tolylene diisocyanate, 4' -diphenylmethane diisocyanate, and Xylylene Diisocyanate (XDI). Further, there may be mentioned modified polyisocyanates obtained by modifying the above isocyanate-based compound (isocyanate-based crosslinking agent) with allophanate bond, biuret bond, isocyanurate bond, uretdione bond, urea bond, carbodiimide bond, uretonimine bond, oxadiazinetrione bond or the like.

Examples of commercially available products of the isocyanate compound (isocyanate crosslinking agent) include TAKENATE 300S, TAKENATE 500, TAKENATE D110N, TAKENATE D140N, TAKENATE D165N, TAKENATE D178N (manufactured by Mitsui chemical Co., Ltd.), SUMIDUR T80, SUMIDUR L, DESMODUR N3400 (manufactured by Suzuki Kaishi Co., Ltd.), MILLIONATE MR, MILLIONATE MT, COLONATE L, COLONATE HL, and COLONATE HX (manufactured by Nippon polyurethane industries Co., Ltd.). These isocyanate compounds may be used in combination of 2 or more, or may be used in combination of 2-functional isocyanate compounds and 3-functional isocyanate compounds. By using a crosslinking agent in combination, an adhesive sheet having excellent shear force and preventing an increase in adhesive force with time can be obtained.

Examples of the epoxy compound include N, N, N ', N' -tetraglycidyl-m-xylyldiamine (trade name TETRAD-X, manufactured by Mitsubishi gas chemical corporation), 1, 3-bis (N, N-diglycidylaminomethyl) cyclohexane (trade name TETRAD-C, manufactured by Mitsubishi gas chemical corporation), and the like.

Examples of the melamine resin include hexamethylolmelamine. Examples of the aziridine derivative include trade names HDU, TAZM and TAZO (manufactured by CRP Co., Ltd.) which are commercially available.

The metal chelate compound includes, as a metal component, aluminum, iron, tin, titanium, nickel, and the like, and as a chelate component, acetylene, methyl acetoacetate, ethyl lactate, and the like.

The content (total amount) of the crosslinking agent used in the present invention is, for example, preferably 0.01 to 10 parts by mass, more preferably 0.1 to 8 parts by mass, further preferably 0.5 to 5 parts by mass, and most preferably 1.0 to 4 parts by mass based on 100 parts by mass of the (meth) acrylic polymer. When the content is less than 0.01 part by mass, crosslinking formation by the crosslinking agent becomes insufficient, the cohesive force of the obtained adhesive agent layer becomes small, and sufficient heat resistance may not be obtained, and the content tends to cause adhesive residue. On the other hand, when the content exceeds 10 parts by mass, the cohesive force of the polymer is large, the fluidity is lowered, the wetting with an adherend (for example, a polarizing plate as an optical member or the like) becomes insufficient, and the swelling between the adherend and the adhesive composition layer tends to occur. Further, when the amount of the crosslinking agent is large, the peeling electrification characteristics tend to be lowered. These crosslinking agents may be used alone, or 2 or more kinds thereof may be used in combination.

The blending ratio of the aromatic isocyanate compound and the aliphatic isocyanate compound is not particularly limited, and for example, (aromatic isocyanate compound/aliphatic isocyanate compound) (mass ratio) is preferably 3/1 to 1/50, more preferably 2/1 to 1/40, and further preferably 1/1 to 1/30. When the blending ratio is the above ratio, the increase in the adhesive force with time can be prevented, which is useful.

The adhesive composition may further contain a crosslinking catalyst in order to more effectively promote any of the above crosslinking reactions. Examples of the crosslinking catalyst include tin catalysts such as dibutyltin dilaurate and dioctyltin dilaurate, iron tris (acetylacetonate), iron tris (hexane-2, 4-dione), iron tris (heptane-3, 5-dione), iron tris (5-methylhexane-2, 4-dione), iron tris (octane-2, 4-dione), iron tris (6-methylheptane-2, 4-dione), iron tris (2, 6-dimethylheptane-3, 5-dione), iron tris (nonane-2, 4-dione), iron tris (nonane-4, 6-dione), iron tris (2,2,6, 6-tetramethylheptane-3, 5-dione), iron tris (nonane-2, 4-dione), iron (tetrazinone), and iron, Tri (tridecane-6, 8-dione) iron, tri (1-phenylbutane-1, 3-dione) iron, tri (hexafluoroacetylacetonato) iron, tri (ethyl acetoacetate) iron, tri (n-propyl acetoacetate) iron, tri (isopropyl acetoacetate) iron, tri (n-butyl acetoacetate) iron, tri (sec-butyl acetoacetate) iron, tri (tert-butyl acetoacetate) iron, tri (methyl propionylacetate) iron, tri (ethyl propionylacetate) iron, tri (n-propyl propionylacetate) iron, tri (isopropyl propionylacetate) iron, tri (n-butyl propionylacetate) iron, tri (sec-butyl propionylacetate) iron, tri (tert-butyl propionylacetate) iron, tri (benzyl acetoacetate) iron, tri (dimethyl malonate) iron, tri (diethyl malonate) iron, trimethoxyiron, triethoxy iron, triisopropoxyberric, tri (propyloxy) iron, tri (tert-butyl acetoacetate), tri (tert-butyl acrylate) iron, tri (benzyl acetoacetate), tri (dimethyl malonate) iron, tri (diethyl malonate) iron, trimethoxy iron, triethoxy iron, Iron-based catalysts such as ferric chloride. These crosslinking catalysts may be used in 1 kind, or 2 or more kinds may be used in combination.

The content (amount used) of the crosslinking catalyst is not particularly limited, and is, for example, approximately preferably 0.0001 to 1 part by mass, and more preferably 0.001 to 0.5 part by mass, based on 100 parts by mass of the (meth) acrylic polymer. When the content is within the above range, the crosslinking reaction speed is high in forming the adhesive layer, and the shelf life of the adhesive composition is also prolonged, which is a preferable embodiment.

The adhesive composition of the present invention may contain a polyoxyalkylene chain-containing compound which does not contain an organopolysiloxane. When the adhesive composition contains the above compound, an adhesive composition having more excellent wettability to an adherend can be obtained.

Specific examples of the polyoxyalkylene chain-containing compound not containing an organopolysiloxane include nonionic surfactants such as polyoxyalkylene alkylamines, polyoxyalkylene diamines, polyoxyalkylene fatty acid esters, polyoxyalkylene sorbitan fatty acid esters, polyoxyalkylene alkylphenyl ethers, polyoxyalkylene alkyl ethers, polyoxyalkylene alkylallyl ethers, and polyoxyalkylene alkylphenyl allyl ethers; anionic surfactants such as polyoxyalkylene alkyl ether sulfate, polyoxyalkylene alkyl ether phosphate, polyoxyalkylene alkyl phenyl ether sulfate and polyoxyalkylene alkyl phenyl ether phosphate; and, a cationic surfactant having a polyoxyalkylene chain (polyalkylene oxide chain), a zwitterionic surfactant, a polyether compound having a polyoxyalkylene chain (including derivatives thereof), a polyester compound having a polyoxyalkylene chain (including derivatives thereof), an acrylic compound having a polyoxyalkylene chain (including derivatives thereof), and the like. Further, a polyoxyalkylene chain-containing monomer may be blended as the polyoxyalkylene chain-containing compound with the acrylic polymer. The polyoxyalkylene chain-containing compound may be used alone or in combination of 2 or more.

Specific examples of the polyether compound having a polyoxyalkylene chain include polypropylene glycol (PPG) -polyethylene glycol (PEG) block copolymers, PPG-PEG-PPG block copolymers, PEG-PPG-PEG block copolymers, and the like. Examples of the derivative of the polyether compound having a polyoxyalkylene chain include an oxypropylene group-containing compound whose terminal is etherified (such as PPG monoalkyl ether and PEG-PPG monoalkyl ether), an oxypropylene group-containing compound whose terminal is acetylated (such as end-acetylated PPG), and the like.

Specific examples of the acrylic compound having a polyoxyalkylene chain include (meth) acrylate polymers having an oxyalkylene group. The oxyalkylene group is preferably an oxyalkylene unit having an addition mole number of 1 to 50, more preferably 2 to 30, and further preferably 2 to 20, from the viewpoint of coordination of an ionic compound. The terminal of the oxyalkylene group may be an original hydroxyl group, or may be substituted with an alkyl group, a phenyl group or the like.

The (meth) acrylate polymer having an alkylene oxide is preferably a polymer containing an alkylene oxide as a monomer unit (component), and specific examples of the alkylene oxide (meth) acrylate include ethylene glycol group-containing (meth) acrylates, such as methoxy-polyethylene glycol (meth) acrylates such as methoxy-diethylene glycol (meth) acrylate and methoxy-triethylene glycol (meth) acrylate, ethoxy-polyethylene glycol (meth) acrylates such as ethoxy-diethylene glycol (meth) acrylate and ethoxy-triethylene glycol (meth) acrylate, butoxy-polyethylene glycol (meth) acrylates such as butoxy-diethylene glycol (meth) acrylate and butoxy-triethylene glycol (meth) acrylate, phenoxy-polyethylene glycol (meth) acrylate types such as phenoxy-diethylene glycol (meth) acrylate and phenoxy-triethylene glycol (meth) acrylate, methoxy-polypropylene glycol (meth) acrylate types such as 2-ethylhexyl-polyethylene glycol (meth) acrylate, nonylphenol-polyethylene glycol (meth) acrylate, and methoxy-dipropylene glycol (meth) acrylate, and the like.

Further, as the monomer unit (component), another monomer unit (component) other than the above-mentioned alkylene oxide (meth) acrylate may be used. Specific examples of the other monomer unit include acrylic esters and/or methacrylic esters having an alkyl group having 1 to 14 carbon atoms such as methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, and n-tetradecyl (meth) acrylate.

Further, as other monomer units (components) other than the alkylene oxide (meth) acrylate, a carboxyl group-containing (meth) acrylate, a phosphoric group-containing (meth) acrylate, a cyano group-containing (meth) acrylate, a vinyl ester, an aromatic vinyl compound, an acid anhydride group-containing (meth) acrylate, a hydroxyl group-containing (meth) acrylate, an amide group-containing (meth) acrylate, an amino group-containing (meth) acrylate, an epoxy group-containing (meth) acrylate, N-acryloyl morpholine, a vinyl ether, and the like can be suitably used.

In a preferred embodiment, the polyoxyalkylene chain-containing compound not containing organopolysiloxane is a compound having a (poly) oxyethylene chain in at least a part thereof. By blending the (poly) oxyethylene chain compound, the compatibility of the base polymer with the antistatic component is improved, leakage to an adherend is suppressed well, and an adhesive composition with low staining can be obtained. Among these, when a PPG-PEG-PPG block copolymer is used, an adhesive composition having excellent low-staining properties can be obtained. The polyoxyethylene chain-containing compound preferably has a mass of the (poly) oxyethylene chain in the total compound of 5 to 90 mass%, more preferably 5 to 85 mass%, even more preferably 5 to 80 mass%, and most preferably 5 to 75 mass%.

The molecular weight of the polyoxyalkylene chain-containing compound not containing organopolysiloxane is preferably 50000 or less number average molecular weight (Mn), more preferably 200 to 30000, still more preferably 200 to 10000, and particularly preferably 200 to 5000. If Mn is too large as compared with 50000, compatibility with the acrylic polymer is lowered, and the adhesive agent layer tends to be whitened. If Mn is too small as compared with 200, contamination by the polyoxyalkylene compound may become easy to occur. Here, Mn means a polystyrene equivalent value obtained by GPC (gel permeation chromatography).

Specific examples of commercially available products of the polyoxyalkylene chain-containing compound not containing an organopolysiloxane include Adeka Pluronic 17R-4, Adeka Pluronic 25R-2 (both manufactured by ADEKA Co., Ltd.), EMULGEN120 (manufactured by Kao corporation), and the like.

The amount of the polyoxyalkylene chain-containing compound not containing an organopolysiloxane may be, for example, 0.005 to 20 parts by mass, preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, and most preferably 0.1 to 1 part by mass, based on 100 parts by mass of the (meth) acrylic polymer. If the amount is too small, the effect of preventing leakage of the antistatic component is reduced, and if it is too large, contamination by the polyoxyalkylene compound may easily occur.

Further, the adhesive composition may contain an acrylic oligomer. The weight average molecular weight of the acrylic oligomer is preferably 1000 or more and less than 30000, more preferably 1500 or more and less than 20000, and further preferably 2000 or more and less than 10000. When used in the acrylic pressure-sensitive adhesive composition for re-peeling of the present embodiment, the acrylic pressure-sensitive adhesive composition functions as a tackifier resin, improves the adhesiveness (adhesiveness), and is effective in suppressing swelling of the pressure-sensitive adhesive sheet.

Examples of the (meth) acrylate monomer that can be used for the acrylic oligomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, alkyl (meth) acrylates such as 2-ethylhexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, and dodecyl (meth) acrylate;

aryl (meth) acrylates such as phenyl (meth) acrylate and benzyl (meth) acrylate;

(meth) acrylic acid esters obtained from terpene compound derivative alcohols, and the like.

The (meth) acrylic monomer having an alicyclic structure can be used in the acrylic oligomer, and examples thereof include (meth) acrylates such as dicyclopentyl methacrylate, dicyclopentyl acrylate, dicyclopentyloxyethyl methacrylate, dicyclopentyloxyethyl acrylate, tricyclopentyl methacrylate, tricyclopentyl acrylate, 1-adamantyl methacrylate, 1-adamantyl acrylate, 2-methyl-2-adamantyl methacrylate, 2-methyl-2-adamantyl acrylate, 2-ethyl-2-adamantyl methacrylate, and 2-ethyl-2-adamantyl acrylate. Such (meth) acrylic monomers may be used alone or in combination of 2 or more.

The acrylic oligomer may be obtained by copolymerizing a monomer component (copolymerizable monomer) other than the (meth) acrylic monomer component unit, the monomer component being copolymerizable with the (meth) acrylic monomer.

The weight average molecular weight of the acrylic oligomer is 1000 or more and less than 30000, preferably 1500 or more and less than 20000, and more preferably 2000 or more and less than 10000. If the weight average molecular weight is 30000 or more, tackiness (adhesiveness) is lowered. In addition, if the weight average molecular weight is less than 1000, it becomes a low molecular weight, thus causing a decrease in the adhesive force of the adhesive sheet.

Further, the adhesive composition may contain a compound that causes keto-enol tautomerism as a crosslinking retarder. For example, in an adhesive composition containing a crosslinking agent or an adhesive composition capable of being used in combination with a crosslinking agent, a mode including the compound which causes keto-enol tautomerism can be preferably employed. This can suppress excessive increase in viscosity or gelation of the adhesive composition after blending of the crosslinking agent, and can achieve the effect of extending the shelf life of the adhesive composition. It is particularly interesting to include compounds which cause keto-enol tautomerism, at least when isocyanate compounds are used as the cross-linking agent. This technique can be preferably applied, for example, to the case where the adhesive composition is in the form of an organic solvent solution or solvent-free.

As the compound which causes keto-enol tautomerism, various β -dicarbonyl compounds can be used. Specific examples thereof include: beta-diketones such as acetylacetone, 2, 4-hexanedione, 3, 5-heptanedione, 2-methylhexane-3, 5-dione, 6-methylheptane-2, 4-dione, and 2, 6-dimethylheptane-3, 5-dione; acetoacetic acid esters such as methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate, and tert-butyl acetoacetate; propionyl acetic acid esters such as propionyl ethyl acetate, propionyl isopropyl acetate, propionyl tert-butyl acetate, and the like; isobutyrylacetic acid esters such as ethyl isobutyrylacetate, isopropyl isobutyrylacetate, and tert-butyl isobutyrylacetate; malonic esters such as methyl malonate and ethyl malonate; and the like. Among them, preferred compounds include acetylacetone and acetoacetates. The compound which causes keto-enol tautomerism may be used alone, or 2 or more kinds may be used in combination.

The content of the compound which causes keto-enol tautomerism may be, for example, 0.1 to 20 parts by mass, and usually 0.5 to 15 parts by mass (for example, 1 to 10 parts by mass) is suitable for 100 parts by mass of the (meth) acrylic polymer. If the amount of the compound is too small, it may be difficult to exhibit sufficient use effects. On the other hand, if the compound is used in an amount larger than necessary, the compound may remain in the adhesive agent layer to reduce the cohesive force.

The pressure-sensitive adhesive composition used in the pressure-sensitive adhesive sheet of the present invention may further contain other known additives, and for example, powders such as coloring agents and pigments, surfactants, plasticizers, tackifiers, low molecular weight polymers, surface lubricants, leveling agents, antioxidants, anticorrosive agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, silane coupling agents, inorganic or organic fillers, metal powders, particles, foils, and the like may be appropriately added depending on the application.

The adhesive sheet of the present invention is characterized in that the adhesive sheet has an adhesive layer formed of the adhesive composition (formed by crosslinking the adhesive composition) on one side or both sides of the support film, and in this case, the crosslinking of the adhesive composition is generally performed after the application of the adhesive composition, but the adhesive layer formed of the crosslinked adhesive composition may be transferred to the support film or the like. The method for forming the adhesive layer on the support film is not particularly limited, and the adhesive layer can be produced, for example, as follows: the adhesive composition is coated on a support film, and the polymerization solvent and the like are dried and removed to form an adhesive layer on the support film. Thereafter, curing may be performed for the purpose of adjusting the migration of components in the adhesive layer, adjusting the crosslinking reaction, and the like. In the case of producing an adhesive sheet by applying the adhesive composition to a support film, one or more solvents other than the polymerization solvent may be added to the adhesive composition again in order to uniformly coat the adhesive composition on the support film.

In addition, as a method for forming the adhesive layer in the production of the adhesive sheet of the present invention, a known method used in the production of adhesive sheets can be used. Specific examples thereof include roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, and extrusion coating using a die coater.

The adhesive sheet of the present invention is generally produced such that the thickness of the adhesive layer is preferably 3 to 100 μm, more preferably about 5 to 50 μm. When the thickness of the adhesive layer is within the above range, a proper balance between removability and adhesiveness (adhesiveness) can be easily obtained, and therefore, the thickness is preferable.

< baffle plate >

In the adhesive sheet (surface protective film) of the present invention, a separator may be bonded to the surface of the adhesive layer as necessary for the purpose of protecting the adhesive surface.

As a material constituting the separator, there are paper and a plastic film, but a plastic film is preferably used in view of excellent surface smoothness. The film is not particularly limited as long as it can protect the adhesive layer, and examples thereof include a polyethylene film, a polypropylene film, a polybutylene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

The thickness of the separator is usually 5 to 200 μm, preferably about 10 to 100 μm. When the content is within the above range, workability of bonding to the adhesive agent layer and workability of peeling from the adhesive agent layer are excellent, and therefore, the content is preferable. The separator may be subjected to release and anti-fouling treatment using a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, silica powder or the like, or antistatic treatment such as coating type, doping type, vapor deposition type or the like, as necessary.

The adhesive sheet of the present invention is an adhesive sheet having an adhesive layer formed from an adhesive composition on one or both surfaces of a support film, wherein the adhesive ratio (B/a) between the adhesive force (a) at a peeling speed of 30 m/min after the adhesive surface of the adhesive layer is adhered to the TAC surface at 23 ℃ for 30 minutes and the adhesive force (B) at a peeling speed of 30 m/min after the adhesive surface of the adhesive layer is adhered to the TAC surface at 70 ℃ for 1 week is less than 2, preferably 0.5 to 1.9, and more preferably 0.7 to 1.8. When the amount is within the above range, the adhesion force increase preventing property (adhesion force stability) is excellent even in high-speed peeling after a high-temperature lapse of time, and the removability and workability are excellent, which is a preferable embodiment.

The adhesive force (A) at a peeling speed of 30 m/min after the adhesive surface of the adhesive layer is adhered to the TAC surface at 23 ℃ for 30 minutes is preferably 2.0N/25mm or less, more preferably 0.1 to 1.9N/25mm, and still more preferably 0.1 to 1.8N/25 mm. If the above-mentioned adhesive force (A) exceeds 2.0N/25mm, the adhesive sheet (surface protective film) is difficult to peel from the adherend, the peeling workability when the adhesive sheet becomes unnecessary is poor, and further, the adherend is damaged by the peeling step, etc., which is not preferable.

The adhesive force (B) at a peeling speed of 30 m/min after the adhesive surface of the adhesive layer is adhered to the TAC surface for 1 week at 70 ℃ is preferably 4.0N/25mm or less, more preferably 0.1 to 3.5N/25mm, and still more preferably 0.1 to 3.0N/25 mm. If the above-mentioned adhesive force (B) exceeds 4.0N/25mm, the adhesive sheet (surface protective film) is difficult to peel from the adherend, the peeling workability when the adhesive sheet becomes unnecessary is poor, and further, the adherend is damaged by the peeling step, etc., which is not preferable.

In the adhesive sheet of the present invention, the ratio (B/a) of the adhesive force (a) at a peeling speed of 30 m/min after the adhesive surface of the adhesive layer is adhered to the TAC surface at 23 ℃ for 30 minutes to the adhesive force (B) at a peeling speed of 30 m/min after the adhesive surface of the adhesive layer is adhered to the TAC surface at 70 ℃ for 1 week is less than 2, preferably 0.5 to 1.9, and more preferably 0.7 to 1.8. When the content is within the above range, the removability and workability are excellent, and this is a preferable embodiment.

In addition, the first and second substrates are,in the adhesive sheet of the present invention, the adhesive layer has an adhesive area of 1cm²The shear force when the sheet is attached to a TAC polarizing plate and peeled off at a peeling rate of 0.06 mm/min in the shear direction after 30 minutes at 23 ℃ is preferably 10N/cm²More preferably 10 to 50N/cm²More preferably 10 to 40N/cm². If the shear force is within the above range, the force in the shear direction generated when the adherend is to be curled can be received, and the curling of the adherend can be suppressed without causing slipping or displacement of the adhesive sheet.

< anti-static layer (topcoat) >)

The pressure-sensitive adhesive sheet of the present invention preferably has an antistatic layer on one surface of the support film on the side opposite to the pressure-sensitive adhesive layer, the antistatic layer being formed from an antistatic agent composition containing polyaminobenzene sulfonic acid as a conductive polymer component, a polyester resin as a binder, and an isocyanate-based crosslinking agent as a crosslinking agent. The pressure-sensitive adhesive sheet preferably has an antistatic layer (topcoat layer) to improve antistatic properties of the pressure-sensitive adhesive sheet.

< conductive Polymer >

The antistatic layer preferably contains polyaminobenzene sulfonic acid as a conductive polymer component. By using the conductive polymer, antistatic properties based on an antistatic layer can be satisfied. The polyaminobenzene sulfonic acid is "water-soluble", and can be immobilized in the antistatic layer by using an isocyanate-based crosslinking agent described later, thereby improving water resistance. By using an aqueous solution containing the water-soluble conductive polymer, an antistatic layer having excellent surface resistance value with time can be obtained, which is a preferable embodiment. On the other hand, when the conductive polymer used for forming the antistatic layer is "water-dispersible", if the antistatic layer is formed using a solution containing the water-dispersible conductive polymer, aggregates are likely to be generated, and the coating cannot be performed uniformly, and the surface resistance value tends to be remarkably deteriorated with time, which is not preferable.

The amount of the conductive polymer used is preferably 10 to 200 parts by mass, more preferably 25 to 150 parts by mass, and still more preferably 40 to 120 parts by mass, based on 100 parts by mass of the binder contained in the antistatic layer (top coat layer). If the amount of the conductive polymer used is too small, the antistatic effect may be reduced, and if the amount of the conductive polymer used is too large, the adhesion of the antistatic layer to the support film may be reduced, or the transparency may be reduced, which is not preferable.

The weight average molecular weight (Mw) of the polyaminobenzene sulfonic acid used as the conductive polymer component in terms of polystyrene is preferably 5 × 10⁵Hereinafter, 3 × 10 is more preferable⁵In addition, the weight average molecular weight of these conductive polymers is preferably 1 × 10 in general³Above, more preferably 5 × 10³The above.

As a method for forming the antistatic layer, a method of applying a coating material for forming an antistatic layer (antistatic agent composition) on the first surface of the support film and drying (or curing) the coating material can be adopted, and it is preferable to contain polyaminobenzene sulfonic acid as a conductive polymer component used in the preparation of the coating material, a polyester resin as a binder, and an isocyanate-based crosslinking agent as a crosslinking agent, and it is preferable to use a form in which the essential component is dissolved in water (conductive polymer aqueous solution, or simply referred to as aqueous solution). The aqueous conductive polymer solution can be prepared, for example, by dissolving a conductive polymer having a hydrophilic functional group (which can be synthesized by a method such as copolymerization of a monomer having a hydrophilic functional group in the molecule) in water. Examples of the hydrophilic functional group include a sulfonic acid group, an amino group, an amide group, an imino group, a hydroxyl group, a mercapto group, a hydrazine group, a carboxyl group, a quaternary ammonium group, and a sulfate group (-O-SO)₃H) Phosphate groups (e.g., -O-PO (OH)₂) And the like. The hydrophilic functional groups may also form salts.

Examples of commercially available products of the aqueous polyaminobenzene sulfonic acid solution include products under the trade name "aquaPASS" manufactured by mitsubishi yang corporation.

The antistatic layer disclosed herein contains polyaminobenzene sulfonic acid (polyaniline type) as an essential component as a conductive polymer component, but may also contain 1 or 2 or more other antistatic components (organic conductive materials other than conductive polymers, inorganic conductive materials, antistatic agents, etc.), for example. Here, as a preferable aspect, an aspect in which the antistatic layer does not substantially contain an antistatic component other than the conductive polymer, that is, an aspect in which the antistatic component contained in the antistatic layer is substantially formed only of the conductive polymer may be more preferably implemented.

Examples of the organic conductive material include a cationic antistatic agent having a cationic functional group such as a quaternary ammonium salt, a pyridinium salt, a primary amino group, a secondary amino group, or a tertiary amino group; anionic antistatic agents having anionic functional groups such as sulfonate, sulfate ester salt, phosphonate and phosphate ester salt; amphoteric antistatic agents such as alkylbetaines and derivatives thereof, imidazolines and derivatives thereof, and alanines and derivatives thereof; nonionic antistatic agents such as aminoalcohol and its derivatives, glycerin and its derivatives, polyethylene glycol and its derivatives, and the like; an ion-conductive polymer obtained by polymerizing or copolymerizing the cationic, anionic, or zwitterionic monomer having an ion-conductive group (for example, a quaternary ammonium salt group); and conductive polymers such as polythiophene, polyaniline, polypyrrole, polyethyleneimine, and allylamine polymers. Such antistatic agents may be used alone in 1 kind, or 2 or more kinds may be used in combination.

Examples of the inorganic conductive material include tin oxide, antimony oxide, indium oxide, cadmium oxide, titanium oxide, zinc oxide, indium, tin, antimony, gold, silver, copper, aluminum, nickel, chromium, titanium, iron, cobalt, copper iodide, ITO (indium oxide/tin oxide), ATO (antimony oxide/tin oxide), and the like. Such inorganic conductive material can be used alone in 1, can also be used in 2 or more combination.

Examples of the antistatic agent include cationic antistatic agents, anionic antistatic agents, zwitterionic antistatic agents, nonionic antistatic agents, and ion-conductive polymers obtained by polymerizing or copolymerizing monomers having the above cationic, anionic, and zwitterionic ion-conductive groups.

< adhesive >

The antistatic layer preferably contains a polyester resin as a binder. The polyester resin is preferably a resin material containing a polyester as a main component (typically, a component accounting for more than 50 mass%, preferably 75 mass% or more, for example, 90 mass% or more). The polyester, typically, preferably has the following structure: a structure obtained by condensing 1 or 2 or more compounds (polycarboxylic acid component) selected from polycarboxylic acids (typically dicarboxylic acids) having 2 or more carboxyl groups in 1 molecule and derivatives thereof (anhydrides, esters, halides, and the like of the polycarboxylic acids) with 1 or 2 or more compounds (polyol component) selected from polyhydric alcohols (typically glycols) having 2 or more hydroxyl groups in 1 molecule.

Examples of the compound which can be used as the polycarboxylic acid component include oxalic acid, malonic acid, difluoromalonic acid, alkylmalonic acid, succinic acid, tetrafluorosuccinic acid, alkylsuccinic acid, (±) -malic acid, meso-tartaric acid, itaconic acid, maleic acid, methylmaleic acid, fumaric acid, methylfumaric acid, acetylenedicarboxylic acid, glutaric acid, hexafluoroglutaric acid, methylglutaric acid, glutaconic acid, aliphatic dicarboxylic acids such as adipic acid, dithioadipic acid, methyladipic acid, dimethyladipic acid, tetramethyladipic acid, methyleneadipic acid, muconic acid, galactaric acid, pimelic acid, suberic acid, perfluorosuberic acid, 3,6, 6-tetramethylsuberic acid, azelaic acid, sebacic acid, perfluorosebacic acid, tridecanedioic acid, dodecanedicarboxylic acid, tridecanedicarboxylic acid, and tetradecanedicarboxylic acid; alicyclic dicarboxylic acids such as cycloalkyldicarboxylic acids (e.g., 1, 4-cyclohexanedicarboxylic acid, 1, 2-cyclohexanedicarboxylic acid), 1,4- (2-norbornene) dicarboxylic acid, 5-norbornene-2, 3-dicarboxylic acid (bicycloheptene dicarboxylic acid), adamantanedicarboxylic acid, and spiroheptane dicarboxylic acid; phthalic acid, isophthalic acid, dithioisophthalic acid, methylisophthalic acid, dimethylisophthalic acid, chloromisophthalic acid, dichloroisophthalic acid, terephthalic acid, methylterephthalic acid, dimethylterephthalic acid, chloroterephthalic acid, bromoterephthalic acid, naphthalenedicarboxylic acid, fluorenone dicarboxylic acid, anthracene dicarboxylic acid, biphenyldicarboxylic acid, biphenylenedicarboxylic acid, dimethylbiphenylenedicarboxylic acid, 4 '-p-tetraphenyldicarboxylic acid (4, 4' -p-terphenylene dicarboxylic acid), 4 '-p-quaterphenyldicarboxylic acid (4, 4' -p-quaterphenylene dicarboxylic acid), bibenzyldicarboxylic acid, azobenzenedicarboxylic acid, homophthalic acid, phenylenediacetic acid, phenylenedipropionic acid, naphthalenedicarboxylic acid, biphenyldiacetic acid, biphenyldipropionic acid, biphenyldiacetic acid, and biphenyldipropionic acid, Aromatic dicarboxylic acids such as 3,3' - [4,4 ' - (methylenebis-p-biphenylene) dipropionic acid, 4 ' -bibenzyldiacetic acid, 3' (4,4 ' -bibenzyl) dipropionic acid, oxydi-p-phenylenediacetic acid, etc.; anhydrides of any of the above polycarboxylic acids; esters (e.g., alkyl esters, monoesters, diesters, etc.) of any of the above polycarboxylic acids; acid halides corresponding to any of the above polycarboxylic acids (e.g., dicarboxylic acid chlorides); and the like.

Suitable examples of the compound that can be used as the polycarboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, and anhydrides thereof; aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, succinic acid, fumaric acid, maleic acid, bicycloheptene dicarboxylic acid and 1, 4-cyclohexanedicarboxylic acid, and anhydrides thereof; and lower alkyl esters of the above dicarboxylic acids (for example, esters with monohydric alcohols having 1 to 3 carbon atoms).

On the other hand, examples of the compound that can be used as the polyol component include glycols such as ethylene glycol, propylene glycol, 1, 2-propanediol, 1, 3-butanediol, 1, 4-butanediol, neopentyl glycol, 1, 5-pentanediol, 1, 6-hexanediol, 3-methylpentanediol, diethylene glycol, 1, 4-cyclohexanedimethanol, 3-methyl-1, 5-pentanediol, 2-methyl-1, 3-propanediol, 2-diethyl-1, 3-propanediol, 2-butyl-2-ethyl-1, 3-propanediol, xylylene glycol (xylylene glycol), hydrogenated bisphenol a, and bisphenol a. Other examples thereof include alkylene oxide adducts (e.g., ethylene oxide adducts, propylene oxide adducts, etc.) of these compounds.

The molecular weight of the polyester resin may be, for example, 5 × 10 as a weight average molecular weight (Mw) in terms of standard polystyrene measured by Gel Permeation Chromatography (GPC)³～1.5×10⁵Left and right (preferably 1 × 10)⁴～6×10⁴Left and right). The glass transition temperature (Tg) of the polyester resin may be, for example, 0 to 120 ℃ (preferably 10 to 80 ℃).

As the polyester resin, there can be used commercially available product name "VYLONAL MD-1480" manufactured by Toyo Boseki Co.

The antistatic layer (topcoat layer) may further contain a resin other than a polyester resin (for example, 1 or 2 or more resins selected from acrylic resins, acrylic-urethane resins, acrylic-styrene resins, acrylic-silicone resins, polyurethane resins, fluorine resins, polyolefin resins, and the like) as a binder, as long as the performance (for example, antistatic performance and other performance) of the pressure-sensitive adhesive sheet (surface protective film) disclosed herein is not significantly impaired. One preferred mode of the technology disclosed herein is: the binder of the antistatic layer is substantially formed only of the polyester resin. For example, the antistatic layer is preferably formed such that the polyester resin accounts for 98 to 100 mass% of the binder. The proportion of the binder in the entire antistatic layer may be, for example, 50 to 95 mass%, and is preferably 60 to 90 mass%.

< Lubricant >)

The antistatic layer (topcoat) preferably uses a fatty acid amide as a lubricant. By using a fatty acid amide as the lubricant, an antistatic layer (top coat layer) having both sufficient slidability and print adhesion can be obtained even in an embodiment in which no further peeling treatment (for example, a treatment of applying a known peeling treatment agent such as a silicone-based peeling agent or a long chain alkyl-based peeling agent and drying the applied peeling treatment agent) is performed on the surface of the antistatic layer, and thus, this embodiment can be a preferable embodiment. In this manner, a mode in which no further peeling treatment is performed on the surface of the antistatic layer is preferable in terms of preventing whitening due to the peeling treatment agent (for example, whitening due to storage under a heated and humidified condition) in advance. Further, it is also advantageous in view of solvent resistance.

Specific examples of the fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, oleic acid amide, erucic acid amide, N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, methylol stearic acid amide, methylene bisstearic acid amide, ethylene bisdecanoic acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N '-distearyl adipic acid amide, N' -distearyl sebacic acid amide, N-stearoyl oleic acid amide, N-stearoyl stearic acid amide, N, Ethylene bis-oleamide, ethylene bis-erucamide, hexamethylene bis-oleamide, N ' -dioleyl adipic acid amide, N ' -dioleyl sebacic acid amide, m-xylylene bis-stearic acid amide, m-xylylene bis-hydroxystearic acid amide, N ' -stearyl isophthalic acid amide, and the like. These lubricants may be used alone in 1 kind, or 2 or more kinds may be used in combination.

The proportion of the lubricant in the entire antistatic layer may be 1 to 50 mass%, and is preferably 5 to 40 mass%. If the content ratio of the lubricant is too small, the sliding property tends to be easily lowered. If the content of the lubricant is too high, the printing adhesion may be reduced.

The technology disclosed herein may be implemented in such a manner that the antistatic layer (topcoat layer) contains a lubricant other than the fatty acid amide, as long as the application effect is not significantly impaired. Examples of the other lubricant include various waxes such as petroleum-based wax (paraffin wax, etc.), mineral-based wax (montan wax, etc.), higher fatty acid (cerotic acid, etc.), and neutral fat (palmitic acid triglyceride, etc.). Alternatively, the lubricant may contain a general silicone lubricant, a fluorine lubricant, or the like in addition to the wax. The technique disclosed herein is preferably carried out so as not to substantially contain the silicone-based lubricant, the fluorine-based lubricant, and the like. However, the lubricant does not exclude the silicone compound used for other purposes (for example, an antifoaming agent as a coating material for forming an antistatic layer described later) from being contained within a range not to significantly impair the application effect of the technology disclosed herein.

< crosslinking agent >

The antistatic layer preferably contains an isocyanate-based crosslinking agent as a crosslinking agent. By using the isocyanate-based crosslinking agent, water-soluble polyaminobenzene sulfonic acid as an essential component can be fixed in a binder when forming an antistatic layer, and the effects such as excellent water resistance and improvement of printing adhesion can be achieved.

As the isocyanate-based crosslinking agent, a blocked isocyanate-based crosslinking agent which is stable even in an aqueous solution is preferably used. Specific examples of the blocked isocyanate crosslinking agent include those obtained by blocking an isocyanate crosslinking agent (for example, an isocyanate compound (isocyanate crosslinking agent) used in the adhesive agent layer) used in the production of a general adhesive agent layer or antistatic layer (top coat layer) with an alcohol, a phenol, a thiophenol, an amine, an imide, an oxime, a lactam, an active methylene compound, a thiol, an imine, a urea, a diaryl compound, or sodium hydrogen sulfite.

The antistatic layer in the technology disclosed herein may contain additives such as antistatic components, antioxidants, colorants (pigments, dyes, etc.), fluidity modifiers (thixotropic agents, thickeners, etc.), film-forming aids, surfactants (defoaming agents, etc.), preservatives, and the like, as necessary.

< formation of antistatic layer >

The antistatic layer (top coat layer) can be preferably formed by a method including applying a liquid composition (coating material for forming an antistatic layer) in which an essential component such as the conductive polymer component and an additive used as needed are dissolved in an appropriate solvent (water or the like) to the support film. For example, the following method is preferably employed: the coating material is applied to the first surface of the support film, dried, and subjected to curing treatment (heat treatment, ultraviolet treatment, or the like) as necessary. The NV (nonvolatile content) of the coating material may be, for example, 5 mass% or less (typically 0.05 to 5 mass%), and usually 1 mass% or less (typically 0.10 to 1 mass%) is suitable. In the case of forming an antistatic layer having a small thickness, the NV of the coating material is preferably 0.05 to 0.50 mass% (e.g., 0.10 to 0.40 mass%), for example. By using such a low NV coating material, a more uniform antistatic layer can be formed.

As the solvent constituting the coating material for forming an antistatic layer, a solvent capable of stably dissolving the components for forming an antistatic layer is preferable. The solvent may be an organic solvent, water, or a mixed solvent thereof. As the organic solvent, for example, esters selected from ethyl acetate and the like; ketones such as methyl ethyl ketone, acetone, and cyclohexanone; cyclic ethers such as Tetrahydrofuran (THF) and dioxane; aliphatic or alicyclic hydrocarbons such as n-hexane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; aliphatic or alicyclic alcohols such as methanol, ethanol, n-propanol, isopropanol and cyclohexanol; and 1 or 2 or more glycol ethers such as alkylene glycol monoalkyl ether (e.g., ethylene glycol monomethyl ether, ethylene glycol monoethyl ether), and dialkylene glycol monoalkyl ether. In a preferred embodiment, the solvent of the coating material is water or a mixed solvent containing water as a main component (for example, a mixed solvent of water and ethanol).

< Property of antistatic layer >

The thickness of the antistatic layer is typically 3 to 500nm, preferably 3 to 100nm, and more preferably 3 to 60 nm. If the thickness of the antistatic layer is too small, it becomes difficult to form the antistatic layer uniformly (for example, in the case of the thickness of the antistatic layer, variation in thickness due to position becomes large), and therefore, the appearance of the pressure-sensitive adhesive sheet (surface protective film) may be likely to be uneven. On the other hand, if the thickness is too large, the properties (optical properties, dimensional stability, etc.) of the support film may be affected.

In a preferred embodiment of the pressure-sensitive adhesive sheet (surface protective film) disclosed herein, the surface resistance value (Ω/□) measured on the surface of the antistatic layer is preferably less than 1.0 × 10¹¹More preferably less than 5.0 × 10¹⁰More preferably less than 2.0 × 10¹⁰. An adhesive sheet exhibiting a surface resistance value within the above range can be suitably used, for example, as an adhesive sheet used in processing or conveying of an article which is aversive to static electricity, such as a liquid crystal cell or a semiconductor device. Here, the surface resistance value can be calculated from the surface resistance value measured at 23 ℃ and 50% RH using a commercially available insulation resistance measuring apparatus.

The adhesive sheet (surface protective film) disclosed herein preferably has the following properties: the back surface (surface of the antistatic layer) is easily printable with water-based ink or oil-based ink (for example, with an oil-based marker). The pressure-sensitive adhesive sheet is suitable for indicating an identification number or the like of an adherend to be protected on the surface pressure-sensitive adhesive sheet during processing, transportation or the like of the adherend (for example, an optical member) to which the pressure-sensitive adhesive sheet is attached. Therefore, an adhesive sheet having excellent printability is preferable. For example, it is preferable to have high printability to an oil-based ink of a type in which the solvent is alcohol and the pigment is contained. Further, it is preferable that the ink after printing is less likely to be peeled off by rubbing or transfer (that is, excellent printing adhesion). Further, the adhesive sheet disclosed herein preferably has: the solvent resistance is such that the appearance does not change significantly even when the print is erased by alcohol (e.g., ethanol).

The pressure-sensitive adhesive sheet (surface protective film) disclosed herein may be implemented to include other layers in addition to the support film (substrate), the adhesive layer, and the antistatic layer. Examples of the arrangement of the "other layer" include an arrangement between the first surface (back surface) of the support film and the antistatic layer, an arrangement between the second surface (front surface) of the support film and the adhesive layer, and the like. The layer disposed between the front surface of the support film and the adhesive layer may be, for example, an undercoat layer (primer layer) for improving the anchorage of the adhesive layer to the second surface, an antistatic layer, or the like. The adhesive sheet may be one of the following: an antistatic layer is arranged in front of the support film, a primer layer is arranged on the antistatic layer, and an adhesive sheet is arranged on the primer layer.

The optical member of the present invention is preferably an optical member protected by the adhesive sheet. The adhesive sheet can prevent the above-mentioned adhesive force with time (at high temperature), has low adhesive force at the time of high-speed peeling, and is excellent in re-peeling property and workability, and therefore can be used for surface protection purposes at the time of processing, transportation, shipment, and the like, and is useful for protecting the surface of the optical member (polarizing plate and the like). Further, the pressure-sensitive adhesive sheet is excellent in shear force, and therefore can suppress curling of an adherend (optical member) to which the pressure-sensitive adhesive sheet is bonded, and is excellent in handling properties, and therefore is useful.

[ examples ] A method for producing a compound

Hereinafter, examples and the like specifically showing the configuration and effects of the present invention will be described, but the present invention is not limited thereto. Here, the contents of blending and the evaluation of characteristics in examples and the like were measured as follows. Table 1 shows the physical property values of the (meth) acrylic polymer used in the adhesive composition and the blending ratio of the adhesive composition, table 2 shows the blending content of the antistatic layer, and table 3 shows the evaluation results of the properties.

< evaluation >

Specific measurement and evaluation methods are described below.

< determination of weight average molecular weight (Mw) >)

The weight average molecular weight (Mw) was measured using a GPC apparatus (HLC-8220GPC) manufactured by Tosoh corporation. The measurement conditions were as follows.

Sample concentration: 0.2% by mass (THF solution)

Sample injection amount: 10 μ l

Eluent: THF (tetrahydrofuran)

Flow rate: 0.6 ml/min

Measuring temperature: 40 deg.C

Column:

a sample column; TSK guard column Super HZ-H (1 root) + TSK gel SuperHZM-H (2 roots)

A reference column; TSK gel SuperH-RC (1 root)

A detector: differential refraction detector (RI)

Here, the weight average molecular weight is determined as a polystyrene equivalent.

< theoretical value of glass transition temperature >

The glass transition temperature Tg (c) was obtained by the following formula using the following literature value as the glass transition temperature Tgn (c) of the homopolymer of each monomer.

Formula (II): 1/(Tg +273) ═ Σ [ Wn/(Tgn +273) ]

In the formula, Tg (. degree.C.) represents the glass transition temperature of the copolymer, Wn (-) represents the mass fraction of each monomer, Tgn (. degree.C.) represents the glass transition temperature of a homopolymer of each monomer, and n represents the type of each monomer. Angle (c)

Literature values:

2-ethylhexyl acrylate (2 EHA): -70 deg.C

n-Butyl Acrylate (BA): -55 deg.C

Acrylic Acid (AA): 106 deg.C

Carboxyethyl acrylate (β -CEA): 37 deg.C

2-hydroxyethyl acrylate (HEA): -15 deg.C

4-hydroxybutyl acrylate (HBA): -32 deg.C

Hydroxyethyl methacrylate (HEMA): 55 deg.C

N, N-Diethylacrylamide (DEAA): 81 deg.C

Here, as literature values, reference is made to "the synthesis, design, and development of new use of acrylic resins" (published by central business development center), and "Polymer Handbook" (john wiley & Sons).

< measurement of initial adhesion (A) >

A TAC polarizing plate (SEG 1423DU polarizing plate, width: 70mm, length: 100mm, manufactured by Rindong electric Co., Ltd.) was left under an atmosphere of 23 ℃ X50% RH for 24 hours, and then an adhesive sheet cut to a width of 25mm and a length of 100mm was laminated on the adherend at a pressure of 0.25MPa and a speed of 0.3 m/min to prepare an evaluation sample.

After the above lamination, the laminate was left to stand in an atmosphere of 23 ℃ X50% RH for 30 minutes, and then the initial adhesion (A) (N/25mm) when peeled at a peeling speed of 30 m/minute (high speed peeling) and a peeling angle of 180 ℃ by a universal tensile tester was measured. The measurement was carried out under an atmosphere of 23 ℃ X50% RH.

Here, the adhesive force (A) is preferably 2.0N/25mm or less, more preferably 0.1 to 1.9N/25mm, and still more preferably 0.1 to 1.8N/25 mm. If the above-mentioned adhesive force (A) exceeds 2.0N/25mm, the adhesive sheet (surface protective film) is difficult to peel from the adherend, the peeling workability when the adhesive sheet becomes unnecessary is poor, and further, the adherend is damaged by the peeling step, etc., which is not preferable.

< measurement of high-temperature adhesive force (B) with time >

After the above lamination, the laminate was left to stand at 70 ℃ for 1 week (7 days), and then the aged adhesion (B) (N/25mm) was measured by peeling with a universal tensile tester at a peeling speed of 30 m/min (high speed peeling) and a peeling angle of 180 ℃. The measurement was carried out under an atmosphere of 23 ℃ X50% RH.

Here, the adhesive force (B) is preferably less than 4.0N/25mm, more preferably 0.1 to 3.5N/25mm, and still more preferably 0.1 to 3.0N/25 mm. If the above-mentioned adhesive force (B) is 4.0N/25mm or more, the adhesive sheet (surface protective film) is difficult to peel from the adherend, the peeling workability when the adhesive sheet becomes unnecessary is poor, and further, the adherend is damaged by the peeling step, etc., which is not preferable.

< evaluation of adhesion ratio (B/A) >

The adhesion force ratio (B/A) of the adhesion force (A) to the adhesion force (B) is less than 2, preferably 0.5 to 1.9, more preferably 0.7 to 1.8. When the content is within the above range, the removability and workability are excellent, and this is a preferable embodiment. The adhesion ratio was evaluated as an index of the resistance to increase in adhesion at high temperature over time.

< determination of shear force >

The adhesive sheet was cut into a size of 10mm in width and 100mm in length, and after peeling the separator, the adhesive (bonding) area of the adhesive layer of the adhesive sheet was set to 1cm²The sheet was adhered to a TAC polarizing plate (SEG 1423DU polarizing plate, width: 25mm, length: 100mm, manufactured by Nidoku electric industries Co., Ltd.), left at room temperature (23 ℃ C., × 50% RH) for 30 minutes, pulled at a peeling speed of 0.06 mm/min in the shearing direction, and the maximum load (N/cm) at that time was measured²) As a shear force.

Here, the shear force (N/cm)²) Preferably 10 or more, more preferably 10 to 50, and still more preferably 10 to 40. When the shear force is within the above range, the force in the shear direction generated when the adherend is desired to be curled can be received, and the curling of the adherend can be suppressed without causing slipping or displacement of the adhesive sheet.

< measurement of surface resistance value >

Measured by a resistivity meter (Mitsubishi chemical Analyticech, Hiresta-UPMCP-HT450 type) at a temperature of 23 ℃ and a humidity of 50% RH according to JIS-K-6911.

Here, the surface resistance value (Ω/□) of the antistatic layer surface in the present invention is preferably less than 1.0 × 10 at the initial stage and at room temperature (23 ℃ × 50% RH) × 1 weeks (7 days) after standing¹¹More preferably less than 5.0 × 10¹⁰More preferably less than 2.0 × 10¹⁰. An adhesive sheet (surface protective film) exhibiting a surface resistance value within the above range can be suitably used, for example, as an adhesive sheet used in processing or transporting of an article which is resistant to static electricity, such as a liquid crystal cell or a semiconductor device.

< measurement of slidability (dynamic frictional force) >

The adhesive sheet (surface protective film) was cut into a size of 70mm in width and 100mm in length, and was bonded to an acrylic plate (product name "ACRYLITE" manufactured by Mitsubishi Yang corporation, thickness: 1mm, width: 70mm, length: 100mm) to prepare a test piece. The test piece was placed with its back surface (antistatic layer surface) facing downward on a smooth PET film kept horizontal, and a load of 1.5kg was applied to the test piece. The test piece loaded with the load was mounted on a tensile tester with a non-stretchable wire, and the test piece was horizontally pulled at a measurement temperature of 25 ℃ under conditions of a pulling speed of 300 mm/min and a pulling distance of 300mm, and the average value (N: 3) of the kinetic friction force (N) applied to the test piece was determined.

Here, the slidability (dynamic friction force) (N) in the present invention is preferably 5 or less, more preferably 4.5 or less, and further preferably 4 or less. When the amount is within the above range, the treatment of the adherend to which the pressure-sensitive adhesive sheet is attached is advantageous in terms of good slidability and workability of the back surface (antistatic layer surface) of the support film.

< evaluation of printability (print adhesion) >

After printing on the surface of the antistatic layer in a measuring environment of 23 ℃ x 50% RH by Xstamper, manufactured by bantam corporation, a selltotap (registered trademark) manufactured by milwako corporation was pasted on the printing, and then peeled off at a peeling speed of 30 m/min and a peeling angle of 180 °. Then, the peeled surface was visually observed, and the case where 50% or more of the printed area was peeled was evaluated as "x" (poor printability), and the case where 50% or more of the printed area was peeled and remained was evaluated as "o" (good printability).

< preparation method >

Specific methods for producing the (meth) acrylic polymer, the adhesive composition, and the like are described below.

Production of (meth) acrylic Polymer

94.5 parts by mass of 2-ethylhexyl acrylate (2EHA), 5.32 parts by mass of 4-hydroxyethyl acrylate (HEA), 0.18 parts by mass of Acrylic Acid (AA), 0.2 parts by mass of 2, 2' -azobisisobutyronitrile as a polymerization initiator, and 150 parts by mass of ethyl acetate were charged into a four-necked flask equipped with a stirrer, a thermometer, a nitrogen gas inlet tube, and a condenser, and a (meth) acrylic polymer solution (40 mass%) was prepared by introducing nitrogen gas while stirring slowly and performing polymerization reaction for 6 hours while keeping the liquid temperature in the flask at about 65 ℃. The weight average molecular weight of the acrylic polymer was 52 ten thousand, and the glass transition temperature (Tg) was-67 ℃ (see column of adhesive composition 1 in table 1).

< preparation of adhesive composition 1 >

The (meth) acrylic polymer solution (40 mass%) was diluted with ethyl acetate to 20 mass%, and 500 parts by mass (100 parts by mass of the solid content) of the solution were added 1 part by mass (1 part by mass of the solid content) of isocyanurate of trimethylolpropane/tolylene diisocyanate (product of japan polyurethane industries, COLONATE L) which is an aromatic isocyanate compound as a crosslinking agent, 1 part by mass (1 part by mass of the solid content) of isocyanurate of hexamethylene diisocyanate (product of japan polyurethane industries, COLONATE HX)1 part by mass (1 part by mass of the solid content), and 3 parts by mass (0.03 part by mass of the solid content) of dibutyltin dilaurate (1 mass% ethyl acetate solution) as a crosslinking catalyst, and mixed and stirred to prepare adhesive composition 1 (solution).

< preparation of aqueous solution for antistatic layer (Back treatment agent A) >

Polyester resin VYLONAL MD-1480 (25% aqueous solution, manufactured by toyobo corporation) as a binder, polyaminobenzene sulfonic acid (aquaPASS, weight average molecular weight 4 ten thousand, manufactured by mitsubishi yang corporation) as a conductive polymer, isocyanurate body of hexamethylene diisocyanate blocked with diisopropylamine as a crosslinking agent, and oleamide as a lubricant were added to a mixed solvent of water/ethanol (1/3), the binder was 100 parts by mass in terms of solid content, the conductive polymer was 75 parts by mass in terms of solid content, the crosslinking agent was 10 parts by mass in terms of solid content, and the lubricant was 30 parts by mass in terms of solid content, and sufficiently mixed by stirring for about 20 minutes. Thus, an aqueous solution of an antistatic layer having an NV of about 0.4% was prepared.

< preparation of aqueous solution for antistatic layer (Back treatment agent B) >

Polyester resin VYLONAL MD-1480 (25% aqueous solution, manufactured by toyobo co., ltd.), polyaminobenzene sulfonic acid (aquaPASS, weight average molecular weight 4 ten thousand, manufactured by mitsubishi yang co., ltd.) as a binder, isocyanurate body of hexamethylene diisocyanate blocked with diisopropylamine as a crosslinking agent were added to a mixed solvent of water/ethanol (1/3), and the mixture was sufficiently mixed by stirring for about 20 minutes, with the binder being 100 parts by mass in terms of solid content, the conductive polymer being 75 parts by mass in terms of solid content, and the crosslinking agent being 10 parts by mass in terms of solid content. Thus, an aqueous solution of an antistatic layer having an NV of about 0.4% was prepared.

< preparation of aqueous solution for antistatic layer (Back treatment agent C) >

Polyester resin VYLONAL MD-1480 (25% aqueous solution, manufactured by toyobo co., ltd.), aqueous solution (bytron p, h.c. stark co., ltd.) containing 0.5% of poly (3, 4-ethylenedioxythiophene) (PEDOT) and 0.8% of polystyrene sulfonate (weight average molecular weight 15 ten thousand) (PSS) as a conductive polymer, and isocyanurate body of hexamethylene diisocyanate blocked with diisopropylamine as a crosslinking agent were added to a mixed solvent of water and ethanol (1/1), and the mixture was thoroughly mixed with stirring for about 20 minutes, wherein the binder was 100 parts by mass in terms of solid content, the conductive polymer was 50 parts by mass in terms of solid content, and the crosslinking agent was 10 parts by mass in terms of solid content. Thus, an aqueous solution of an antistatic layer having an NV of about 0.4% was prepared.

< preparation of aqueous solution for antistatic layer (Back treatment agent D) >

Polyester resin VYLONAL MD-1480 (25% aqueous solution, manufactured by toyoyo textile) as a binder and polyaminobenzene sulfonic acid (aqua pass, weight average molecular weight 4 ten thousand, manufactured by mitsubishi yang corporation) as a conductive polymer were added to a mixed solvent of water/ethanol (1/3), and the mixture was stirred for about 20 minutes to be sufficiently mixed, the binder being 100 parts by mass in terms of solid content and the conductive polymer being 75 parts by mass in terms of solid content. Thus, an aqueous solution of an antistatic layer having an NV of about 0.4% was prepared.

< preparation of support film with antistatic layer >

An aqueous solution of any of the antistatic layers (back surface treatment agents A to D) was applied to a transparent polyethylene terephthalate (PET) film (polyester film) having a thickness of 38 μm, a width of 30cm and a length of 40cm, which was subjected to corona treatment on one surface (first surface), so that the thickness after drying was 30 nm. The coating was heated at 130 ℃ for 1 minute and dried to prepare an antistatic-layer-provided support film having an antistatic layer on the first surface of the PET film.

< example 1 >

< preparation of adhesive sheet >

The pressure-sensitive adhesive composition 1 (solution) was applied to the surface of the antistatic layer-equipped support film opposite to the antistatic layer, and heated at 130 ℃ for 1 minute to form a pressure-sensitive adhesive layer having a thickness of 15 μm. Subsequently, a silicone-treated surface of a polyethylene terephthalate film (thickness: 25 μm), which was a separator having silicone-treated on one surface, was bonded to the surface of the adhesive layer to prepare an adhesive sheet (surface protective film).

< examples 2 to 17 and comparative examples 1 to 4 >

Adhesive sheets were produced in the same manner as in example 1 based on the blending ratios in tables 1 and 2. Here, the blending amount in table 1 indicates the solid content.

The initial adhesive force a at the time of high-speed peeling and the adhesive force B at the time of high temperature aging of the produced adhesive sheet were measured by the above evaluation methods, and the adhesive force ratio (B/a), the shear force, the initial and aging surface resistance values, the slidability, and the printing adhesion were evaluated. The results obtained are shown in Table 3.

[ TABLE 1 ]

[ TABLE 2 ]

	Conductive polymer	Adhesive agent	Crosslinking agent	Lubricant agent
					Back surface treating agent A	Polyaminobenzene sulfonic acid	Polyester	Isocyanates	Oleic acid amides
Back surface treating agent B	Polyaminobenzene sulfonic acid	Polyester	Isocyanates	-
					Back surface treating agent C	PEDOT/PSS	Polyester	Isocyanates	-
Back surface treating agent D	Polyaminobenzene sulfonic acid	Polyester	-	-

The following are descriptions of abbreviations in table 1 and table 2.

2 EHA: 2-ethylhexyl acrylate

BA: acrylic acid n-butyl ester

AA: acrylic acid (carboxyl group-containing (meth) acrylic acid monomer)

beta-CEA: carboxy ethyl acrylate (carboxyl group-containing (meth) acrylic monomer)

HEA: 2-hydroxyethyl acrylate (hydroxyl group-containing (meth) acrylic monomer)

HBA: acrylic acid 4-hydroxybutyl ester (hydroxyl group-containing (meth) acrylic acid series monomer)

HEMA: hydroxyethyl methacrylate (hydroxyl group-containing (meth) acrylic monomer)

DEAA: n, N-diethyl acrylamide

CL: aromatic isocyanate Compound, trimethylolpropane/tolylene diisocyanate (product name: COLONATE L, manufactured by NIPPON POLYURETHANE INDUSTRIAL CO., LTD.)

HX: aliphatic isocyanate Compound and isocyanurate of hexamethylene diisocyanate (product name: COLONATE HX, manufactured by Nippon polyurethane Co., Ltd.)

HL: aliphatic isocyanate Compound, trimethylolpropane/hexamethylene diisocyanate adduct (product name: COLONATE HL, manufactured by Nippon polyurethane Co., Ltd.)

D110N: aromatic isocyanate Compound and trimethylolpropane/xylylene diisocyanate adduct (trade name: TAKENATE D110N, manufactured by Mitsui chemical Co., Ltd.)

D140N: aliphatic isocyanate Compound TAKENATE D140N, trimethylolpropane/isophorone diisocyanate adduct (product name: TAKENATE D110N, manufactured by Mitsui Chemicals)

PEDOT: conductive polymer, poly (3, 4-ethylenedioxythiophene)

PSS: conductive polymer and polystyrene sulfonate

[ TABLE 3 ]

Note) that "> 1E + 13" in Table 3 indicates that the upper limit value measurable by a resistivity meter is exceeded.

From the results of table 3, it was confirmed that in all examples, the adhesive force ratio (B/a) was in a desired range, the increase of the adhesive force with time at a high temperature was suppressed with respect to the initial adhesive force at the time of high-speed peeling, and the shear force was excellent.

On the other hand, it was confirmed that in all of the comparative examples, the adhesion force was higher than that (B/a) outside the desired range at the initial stage of high-speed peeling, and further, the increase in the adhesive force with time at high temperature was large, and the adhesion force increase preventing property (adhesive force stability), removability, workability, and further the shear force were inferior to those of the examples.

Further, according to the results shown in Table 3, the adhesive sheets of examples 1,5, 9 to 11 and 13 to 17, which had antistatic layers using the back surface treatment agent A prepared by blending desired raw materials (conductive polymer component: polyaminobenzene sulfonic acid, binder: polyester resin, and crosslinking agent: isocyanate-based crosslinking agent) as antistatic layers (antistatic agent composition), satisfied all the evaluation items of surface resistance, sliding property and printing adhesion due to the antistatic layers. On the other hand, it was confirmed that some of the antistatic layers of the back surface treatment agents B to D produced without blending the desired raw materials did not satisfy all the evaluation items of surface resistance, slidability, and print adhesion due to the antistatic layers.

Claims

1. An adhesive sheet characterized by having an adhesive layer comprising an adhesive composition on one surface of a support film,

the adhesive composition contains a (meth) acrylic polymer having a hydroxyl group and a carboxyl group, and a crosslinking agent,

contains 5.1 mass% or more of a hydroxyl group-containing (meth) acrylic monomer and 0.01 mass% or more and less than 0.5 mass% of a carboxyl group-containing (meth) acrylic monomer based on the total amount of monomer components constituting the (meth) acrylic polymer,

the crosslinking agent contains an aromatic isocyanate compound and an aliphatic isocyanate compound,

the mass ratio of the aromatic isocyanate compound to the aliphatic isocyanate compound is 3/1-1/50,

the ratio (B/A) of the adhesive force (B) between the adhesive force (B) when the stripping speed is 30 m/min after the adhesive surface of the adhesive layer is adhered on the TAC surface for 1 week at 70 ℃ and the adhesive force (A) when the stripping speed is 30 m/min after the adhesive surface of the adhesive layer is adhered on the TAC surface for 30 minutes at 23 ℃ is less than 2,

the antistatic layer is formed from an antistatic agent composition containing polyaniline sulfonic acid as a conductive polymer component, a polyester resin as a binder, and an isocyanate-based crosslinking agent as a crosslinking agent.

2. The adhesive sheet according to claim 1,

the antistatic agent composition further contains a fatty acid amide as a lubricant.

3. An optical component characterized in that,

protected by the adhesive sheet of claim 1 or 2.