KR102420775B1 - Protective film, foldable device, and rollable device - Google Patents

Abstract

Provided is a protective film that is excellent in bending recovery properties, does not destroy the barrier layer even when bonded to the back side of a polyimide substrate provided with a barrier layer, is excellent in transparency, and is excellent in foreign material inspection properties. A foldable device and a rollable device provided with such a protective film are provided. A protective film according to an embodiment of the present invention is a protective film directly bonded to a polyimide substrate, has a substrate layer and an adhesive layer, and the substrate layer contains substantially no particles or aggregates of particles having a ferret diameter of 1 μm or more. does not

Description

Protective film, foldable device, and rollable device

The present invention relates to a protective film. The present invention also relates to a foldable device provided with such a protective film, and a rollable device provided with such a protective film.

BACKGROUND ART Protective films are used for reinforcing members of various shapes, protecting surfaces, and the like.

For example, when bonding an integrated circuit (IC) or a flexible printed circuit board (FPC) to a substrate (eg, a TFT substrate) of a semiconductor element, thermocompression bonding is usually performed with an anisotropic conductive film (ACF). When performing such thermocompression bonding, a protective film may be previously bonded and reinforced on the back surface side of the board|substrate of a semiconductor element (for example, patent document 1).

Moreover, as a manufacturing method of a flexible device or rollable device which development is advancing in recent years, generally, on support substrates, such as glass, a peeling layer and a flexible or rollable film substrate are formed, and on the film substrate, A TFT substrate, and also an organic EL layer is formed thereon. And although the support substrate is peeled and a flexible device or a rollable device is manufactured, since a flexible display layer and a rollable display layer are very thin, a problem arises in a device with handling etc. For this reason, a protective film may be bonded and reinforced by the back surface side. Such a conventional protective film has a base material layer and an adhesive layer, and it is considered that a polyester film or an acrylic resin film is preferable as a base material layer, and PET film is used typically (for example, the surface protection film of patent document 2). , 1st protective film of patent document 3).

A substrate for a semiconductor element, a flexible device, or a rollable device may be repeatedly bent, and if the bending characteristic of the protective film bonded to the back side of the substrate is poor, the recovery after bending deteriorates, or in the worst case, it breaks due to repeated bending. It may become or become. Specifically, when a protective film is to be bonded to a bent portion (for example, a movable bent portion of a folding member, etc.), the following problems arise, for example.

When the protective film is bent at an angle, since a compressive force acts on the bent inner diameter side, the protective film itself is deformed to alleviate the force. Specifically, for example, wrinkles tend to occur.

When the protective film is bent at an angle, a pulling stress acts on the bent outer diameter side. For this reason, when the stress is relieve|relaxed, the to-be-adhered body floats generate|occur|produces.

When the protective film is bent at an angle, the thickness of the bent or pulled portion of the protective film is greatly changed, and wrinkles are likely to occur even in such a state, or floating occurs. For example, when a protective film is pulled, the thickness of a protective film becomes very thin, and it becomes easy to generate|occur|produce the float from a to-be-adhered body.

In conventional protective films, such as the surface protection film of patent document 2 and the 1st protective film of patent document 3, such uneven|corrugated tracking to a corner|angular part and a bending part was not fully achieved. In particular, when the protective film is bonded to the movable bent portion, since the bending is repeated, there is a problem in that the protective film has a folded trace (so-called "mark") on the movable bent portion.

On the other hand, when a flexible device or a rollable device is an OLED, a polyimide board|substrate is employ|adopted normally as a board|substrate on which a display area and a terminal part are formed. This polyimide board|substrate is thin, and thickness is about 10 micrometers - 20 micrometers (for example, the polyimide board|substrate of patent document 3). In addition, since the polyimide substrate tends to contain moisture therein, a barrier layer is usually provided on the surface of the polyimide substrate on the side where the display area and the terminal portion are formed in order to prevent deterioration of the organic EL layer due to moisture. have. Since this barrier layer is formed of soft materials, such as SiO and SiN, it is very weak, and it is extremely thin, and it is about 50 nm - 300 nm in thickness (for example, the barrier layer of patent document 3). When a conventional protective film is bonded to the back side of a polyimide substrate provided with such a barrier layer, deformation may occur in the polyimide substrate, and as a result of this deformation, the fragile and very thin barrier layer is destroyed. has a problem

In addition, when bonding an integrated circuit (IC) or a flexible printed circuit board (FPC) to a substrate of a semiconductor element (for example, a TFT substrate, etc.) by thermocompression bonding, the bonding position is confirmed from the back side of the substrate and crimping do For this reason, transparency is calculated|required by the protective film joined to the back surface side of a board|substrate.

In addition, as for a protective film, a foreign material test|inspection is performed in the manufacturing process. Here, in the conventional protective film, a filler is included in the base layer (typically a PET film) to prevent blocking, etc., and only ultra-fine foreign substances with a maximum length of less than 1 μm, which is a passing product level in the foreign material inspection, are included. Also about the product which exists as a foreign material, by recognizing a filler as a foreign material, it may determine as a rejected product, and there exists a problem that productivity will fall.

Japanese Patent No. 560039 publication Japanese Patent No. 6376271 Japanese Patent Laid-Open No. 2017-212038

An object of the present invention is to provide a protective film that is excellent in bending recovery property, does not destroy the barrier layer even when bonded to the back side of a polyimide substrate having a barrier layer, is excellent in transparency, and is excellent in foreign material inspection properties there is Another object of the present invention is to provide a foldable device and a rollable device provided with such a protective film.

MEANS TO SOLVE THE PROBLEM The present inventors examined in order to solve the said subject. As a result, when a protective film was bonded to the back surface side of the polyimide board|substrate provided with a barrier layer, it discovered that the cause that the said barrier layer was destroyed was the particle|grains which exist in this protective film. And it considered the cause which the particle|grains exist, and thought that it was the filler contained in the base material layer of a protective film for blocking prevention. In addition, it was thought that, if such particles could be excluded, excellent transparency and excellent foreign material inspection properties could also be expressed. Then, when the above-mentioned particle|grains were excluded and when it was set as the protective film excellent in bending recovery property, it thought that the subject of this invention could be solved, and it came to complete this invention.

A protective film according to an embodiment of the present invention,

It is a protective film that is directly bonded to a polyimide substrate,

It has a base layer and an adhesive layer,

The substrate layer is substantially free of particles or aggregates of particles having a ferret diameter of 1 μm or more.

In one embodiment, it has a topcoat layer in the surface on the opposite side to the surface which has the said adhesive layer of the said base material layer.

In one embodiment, the said top coat layer contains the binder containing at least 1 sort(s) chosen from a polyester resin and a urethane resin.

In one embodiment, the binder contains a urethane-based resin.

In one embodiment, the top coat layer contains an antistatic component.

In one embodiment, the Young's modulus at 23°C of the base layer is 6.0×10 ⁷ Pa or more.

In one embodiment, the material of the said base material layer is at least 1 sort(s) chosen from polyimide and polyether ether ketone.

In one embodiment, a top coat layer is provided on the surface opposite to the surface having the pressure-sensitive adhesive layer of the base layer, and the top coat layer contains a binder and an antistatic component containing a urethane-based resin, and the material of the base layer is at least one selected from polyimide and polyether ether ketone.

In one embodiment, the protective film of this invention bends at 6 phi and hold|maintains at 90 degreeC for 48 hours, Then, the bending angle after releasing the said bending and leaving it to stand at 23 degreeC and 50%RH for 24 hours is 60 degrees - 180 degrees.

In one embodiment, the total light transmittance of the protective film of this invention is 40 % or more.

In one embodiment, the protective film of this invention has a haze of 10 % or less.

In one embodiment, the adhesive force with respect to the glass plate in 300 mm/min of tensile rates in 23 degreeC of the said adhesive layer, and a 180 degree peel is 1 N/25 mm or more.

In one embodiment, the storage elastic modulus in 25 degreeC of the said adhesive layer is 75 kPa or less.

In one embodiment, Tg of the said adhesive layer is -10 degrees C or less.

In one embodiment, the pressure-sensitive adhesive layer contains an acrylic pressure-sensitive adhesive, and the acrylic pressure-sensitive adhesive contains an acrylic polymer as a base polymer.

In one embodiment, the acrylic polymer is obtained by polymerization of a monomer component (M), and among the monomer components (M), an alkyl (meth)acrylate represented by Formula (1), R ¹ is a hydrogen atom Alternatively, the content of the alkyl (meth)acrylate (m1) which is a methyl group and R ² is a C10-20 chain alkyl group is 5 wt% to 65 wt%.

CH ₂ =C(R ¹ )COOR ² (1)

In one embodiment, in the said monomer component (M), the content rate of 2-ethylhexyl acrylate is 15 weight% - 85 weight%.

In one embodiment, in the said monomer component (M), the total content rate of the said alkyl (meth)acrylate (m1) and the said 2-ethylhexyl acrylate is 65 weight% - 98 weight%.

In one embodiment, R ² in the alkyl (meth)acrylate (m1) is a C10-13 chain alkyl group.

In one embodiment, the said alkyl (meth)acrylate (m1) is lauryl acrylate.

In one embodiment, the said monomer component (M) contains at least 1 sort(s) selected from the group which consists of a hydroxyl-containing monomer, a carboxy-group-containing monomer, and a nitrogen-containing monomer.

In one embodiment, the protective film of the present invention is affixed to the foldable member.

In one embodiment, the foldable member is an OLED.

In one embodiment, the protective film of this invention is affixed to a rollable member.

In one embodiment, the rollable member is an OLED.

A foldable device according to an embodiment of the present invention includes the protective film.

A rollable device according to an embodiment of the present invention includes the protective film.

ADVANTAGE OF THE INVENTION According to this invention, it is excellent in bending recovery property, and even if it joins to the back side of the polyimide board|substrate with a barrier layer, the said barrier layer is not destroyed, It is excellent in transparency, and it can provide the protective film excellent in foreign material inspection property. have. According to the present invention, it is also possible to provide a foldable device and a rollable device provided with such a protective film.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic sectional drawing which shows one Embodiment of the foldable device of this invention, and shows one use form of the protective film of this invention.
It is a schematic sectional drawing explaining the evaluation method of bending recovery property.

≪≪Protection film≫≫

The protective film according to the embodiment of the present invention is typically a protective film directly bonded to a polyimide substrate. That is, the aspect in which the protective film by embodiment of this invention was directly bonded to a polyimide board|substrate constitutes the laminated body structure ([polyimide board|substrate]/[protective film]) of a polyimide board|substrate and a protective film.

As a polyimide board|substrate, arbitrary appropriate polyimide board|substrates can be employ|adopted in the range which does not impair the effect of this invention. A typical example of such a polyimide substrate is a polyimide substrate provided in OLED.

The protective film according to the embodiment of the present invention is excellent in bending recovery properties, does not destroy the barrier layer even if it is bonded to the back side of a polyimide substrate provided with a barrier layer, is excellent in transparency, and is excellent in foreign material inspection property Therefore, it is preferably affixed to the foldable member. As the foldable member, any appropriate member can be employed as long as it is a member capable of repeated bending. As such a foldable member, a foldable optical member, a foldable electronic member, etc. are mentioned, for example, A foldable OLED is mentioned as a representative example. Accordingly, the protective film according to the embodiment of the present invention is typically directly bonded to the polyimide substrate provided in the foldable OLED.

The protective film of the present invention has excellent bending recovery properties, does not destroy the barrier layer even when bonded to the back side of a polyimide substrate provided with a barrier layer, is excellent in transparency, and is excellent in foreign material inspection properties, so it is preferable is affixed to the rollable member. As a rollable member, any suitable member can be employ|adopted as long as it is a member which can repeat winding and rewinding. As such a rollable member, a rollable optical member, a rollable electronic member, etc. are mentioned, for example, A rollable OLED is mentioned, for example. Therefore, the protective film by embodiment of this invention bonds directly to the polyimide board|substrate with which the OLED which is typically rollable was equipped.

The thickness of the polyimide substrate to which the protective film according to the embodiment of the present invention is directly bonded can be set to any appropriate thickness according to the purpose of use of the polyimide substrate. Since the effect of this invention can be expressed further, as such thickness, Preferably it is 1 micrometer - 100 micrometers, More preferably, it is 3 micrometers - 50 micrometers, More preferably, it is 5 micrometers - 25 micrometers, especially Preferably it is 10 micrometers - 20 micrometers.

When the polyimide substrate to which the protective film according to the embodiment of the present invention is directly bonded is a polyimide substrate used for OLED, since the polyimide substrate easily contains moisture therein, the organic EL layer is deteriorated by moisture. it gets easier For this reason, when the polyimide substrate to which the protective film according to the embodiment of the present invention is directly bonded is a polyimide substrate used for OLED, the surface of the polyimide substrate opposite to the side to which the protective film is directly bonded, Preferably, a barrier layer is provided. Since this barrier layer is formed of soft materials, such as SiO and SiN, it is very brittle, and it is extremely thin, and the thickness is about 50 nm - 300 nm typically.

The protective film by embodiment of this invention has a base material layer and an adhesive layer. That is, if the protective film by embodiment of this invention has a base material layer and an adhesive layer, it may have arbitrary appropriate other layers in the range which does not impair the effect of this invention.

One layer may be sufficient as a base material layer, and two or more layers may be sufficient as it. A base material layer is a point which can further express the effect of this invention, Preferably it is one layer.

One layer may be sufficient as an adhesive layer, and two or more layers may be sufficient as it. An adhesive layer is a point which can further express the effect of this invention, Preferably it is one layer.

The protective film by embodiment of this invention may be equipped with arbitrary appropriate release liners for the protection until use, etc. on the surface on the opposite side of the base material layer of an adhesive layer.

As the release liner, for example, a release liner in which the surface of a substrate (liner substrate) such as paper or plastic film is treated with silicone, and a release liner in which the surface of a substrate (liner substrate) such as paper or plastic film is laminated with a polyolefin resin. and the like. As a plastic film as a liner base material, For example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate film, a polybutylene tere A phthalate film, a polyurethane film, an ethylene-vinyl acetate copolymer film, etc. are mentioned.

The thickness of the release liner is preferably 1 µm to 500 µm, more preferably 3 µm to 450 µm, still more preferably 5 µm to 400 µm, and particularly preferably 10 µm to 300 µm.

One embodiment of the protective film of this invention contains the laminated body of a base material layer and an adhesive layer. Another embodiment of the protective film of this invention contains the laminated body formed by laminating|stacking a base material layer, an adhesive layer, and a release liner in this order. Another embodiment of the protective film of this invention contains the laminated body formed by laminating|stacking a top coat layer, a base material layer, and an adhesive layer in this order. Another embodiment of the protective film of this invention contains the laminated body formed by laminating|stacking a top coat layer, a base material layer, an adhesive layer, and a release liner in this order. Another embodiment of the protective film of this invention contains the laminated body formed by laminating|stacking an antistatic layer, a base material layer, and an adhesive layer in this order. Another embodiment of the protective film of this invention contains the laminated body formed by laminating|stacking an antistatic layer, a base material layer, an adhesive layer, and a release liner in this order. Another embodiment of the protective film of this invention contains the laminated body formed by laminating|stacking a top coat layer, an antistatic layer, a base material layer, and an adhesive layer in this order. Another embodiment of the protective film of this invention contains the laminated body formed by laminating|stacking a top coat layer, an antistatic layer, a base material layer, an adhesive layer, and a release liner in this order. Another embodiment of the protective film of this invention contains the laminated body formed by laminating|stacking an antistatic layer, a top coat layer, a base material layer, and an adhesive layer in this order. Another embodiment of the protective film of this invention contains the laminated body formed by laminating|stacking an antistatic layer, a topcoat layer, a base material layer, an adhesive layer, and a release liner in this order. The top coat layer and the antistatic layer will be described later.

The protective film according to the embodiment of the present invention has a total thickness (d) of preferably 1 µm to 500 µm, more preferably 5 µm to 200 µm, still more preferably 10 µm to 150 µm, It is particularly preferably from 20 µm to 100 µm, and most preferably from 30 µm to 80 µm. When the total thickness (d) of the protective film according to the embodiment of the present invention is within the above range, the effect of the present invention can be further expressed.

The protective film according to the embodiment of the present invention has a bending angle of preferably 60 after bending at 6 phi and holding at 90°C for 48 hours, releasing the bending and leaving it to stand at 23°C and 50%RH for 24 hours. degrees to 180 degrees, more preferably 80 degrees to 180 degrees, still more preferably 100 degrees to 180 degrees, particularly preferably 120 degrees to 180 degrees, and most preferably 150 degrees to 180 degrees. If the bending angle of the protective film according to the embodiment of the present invention is within the above range after bending at 6Φ and holding at 90°C for 48 hours, then releasing the bending and leaving it to stand at 23°C and 50%RH for 24 hours, The effect of the present invention can be further expressed.

After bending to 6Φ of the protective film according to the embodiment of the present invention and holding it at 90°C for 48 hours, the bending angle is released, and the bending angle after leaving it to stand at 23°C and 50%RH for 24 hours is the recovery after bending. is an indicator of After bending at 6 phi and holding at 90 degreeC for 48 hours, the said bending is released and the measuring method of the bending angle after leaving it to stand at 23 degreeC and 50 %RH for 24 hours is demonstrated in detail later.

The protective film according to the embodiment of the present invention has a total light transmittance of preferably 40% or more, more preferably 50% or more, still more preferably 60% or more, particularly preferably 70% or more, , most preferably 80% or more. When the total light transmittance of the protective film by embodiment of this invention exists in the said range, the outstanding transparency can further be expressed.

The protective film according to the embodiment of the present invention has a haze of preferably 10% or less, more preferably 8% or less, still more preferably 6% or less, particularly preferably 5% or less, and most Preferably it is 4 % or less. When the haze of the protective film by embodiment of this invention exists in the said range, the outstanding transparency can further be expressed.

The protective film by embodiment of this invention WHEREIN: The surface roughness Ra of the outermost layer surface on the opposite side to an adhesive layer as seen from a base material layer is large or small, or arbitrary values can be employ|adopted. This is, in the protective film according to the embodiment of the present invention, the surface roughness (Ra) may be large even if the base layer does not substantially contain particles or aggregates of particles having a ferret diameter of 1 µm or more in the base layer, or In the protective film which is not an embodiment of the invention, it means that the surface roughness (Ra) may be small even if the base layer contains particles or aggregates of particles having a ferret diameter of 1 µm or more. That is, the surface roughness (Ra) means that there is no correlation with the amount of particles or aggregates of particles having a ferret diameter of 1 μm or more in the base layer.

≪Base layer≫

The thickness of the base layer is preferably 1 μm to 500 μm, more preferably 5 μm to 300 μm, still more preferably 10 μm to 100 μm, particularly preferably 15 μm to 80 μm, and most Preferably it is 20 micrometers - 60 micrometers. When the thickness of the base layer is within the above range, the effect of the present invention can be further expressed.

The base layer has a Young's modulus at 23°C of preferably 6.0×10 ⁷ Pa or more, more preferably 1.0×10 ⁸ Pa or more, still more preferably 5.0×10 ⁸ Pa or more, particularly preferably 8.0×10 ⁸ Pa or more, and most preferably 1.0×10 ⁹ Pa or more. The upper limit of the Young's modulus at 23°C of the base layer is typically preferably 1.0×10 ¹¹ Pa or less. When the Young's modulus at 23°C of the base layer is within the above range, the effects of the present invention can be further expressed. If the Young's modulus at 23° C. of the base layer is too low, if the protective film is bent at an angle, there is a fear that the tension on the outer diameter side cannot be sufficiently maintained with respect to the compression on the inner diameter side, the thickness tends to change, and the adherend There is a possibility that the float from the body is likely to occur. When the Young's modulus at 23°C of the base layer is too high, there is a fear that the protective film cannot be easily deformed. The measuring method of Young's modulus is demonstrated in detail later.

As a material of a base material layer, arbitrary appropriate materials can be employ|adopted in the range which does not impair the effect of this invention. As a material of such a base material layer, a resin material is mentioned typically.

As a resin material as a material of a base material layer, For example, polyimide (PI), polyether ether ketone (PEEK), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), poly Acrylic resins such as methyl methacrylate (PMMA), polycarbonate, triacetyl cellulose (TAC), polysulfone, polyarylate, polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene- Vinyl acetate copolymer (EVA), polyamide (nylon), wholly aromatic polyamide (aramid), polyvinyl chloride (PVC), polyvinyl acetate, polyphenylene sulfide (PPS), fluororesin, cyclic olefin polymer, etc. can be heard

As a resin material as a material of a base material layer, from the point which can further express the effect of this invention, Preferably polyimide (PI), polyether ether ketone (PEEK), polyethylene naphthalate (PEN), a cyclic olefin type polymer at least one selected from among, more preferably at least one selected from polyimide (PI), polyether ether ketone (PEEK), and polyethylene naphthalate (PEN), more preferably is at least one selected from polyimide (PI) and polyether ether ketone (PEEK).

The substrate layer preferably contains substantially no particles or agglomerates of particles having a ferret diameter of 1 μm or more. Ideally, "substantially not included" as used herein means that no (even one) particles having a ferret diameter of 1 µm or more are contained in the base layer, and in reality, for example, using a digital microscope Observing the inside of the substrate layer, the number of particles observed per unit area (0.02mm ² ) of particles having a ferret diameter of 1 μm or more is preferably 9 or less, more preferably 5 or less, still more preferably 3 or less , Especially preferably, the case of 0 is said to be "substantially not included".

In addition, the term “substantially not included” includes those that do not contain particles or aggregates of particles having a “intentionally added” ferret diameter of 1 μm or more in the substrate layer, for example, in the manufacturing process of the substrate layer As an impurity, in the presence of particles or aggregates of particles having a ferret diameter of 1 μm or more, which are unintentionally included, such as when a small amount of particles or agglomerates of particles with a ferret diameter of 1 μm or more are mixed, the effect of the present invention is reduced. If it is a range which does not impair, it can be included in "substantially not included". Of course, even in this case, by observing the inside of the substrate layer using a digital microscope, the number of particles or aggregates of particles having a ferret diameter of 1 μm or more per unit area (0.02 mm ² ) is preferably 9 or less. , more preferably 5 or less, still more preferably 3 or less, particularly preferably 0.

The ferret diameter is an index of the size of the target particle or agglomerate of particles, and is also referred to as a forward diameter. The Ferret diameter is the distance between parallel lines sandwiching the projection image of the particle between parallel lines in a certain direction, and refers to the length of the longest point in a straight line distance. The ferret diameter can be observed and measured with a digital microscope or the like. As the shape of the particles or aggregates of particles, various shapes such as spherical shape, spheroid shape, needle shape, various geometric shapes, and various irregular shapes can be adopted.

The surface resistance value measured on the surface of the base layer is preferably 10 ¹² Ω or less, more preferably 10 ⁴ Ω to 10 ¹² Ω, still more preferably 10 ⁴ Ω to 10 ¹¹ Ω, particularly preferably is 5×10 ⁴ Ω to 10 ¹⁰ Ω, most preferably 10 ⁴ Ω to 10 ⁹ Ω. The protective film exhibiting such a surface resistance value can be suitably used as a protective film used, for example, in a process or conveyance process of an article weak to static electricity, such as a liquid crystal cell or a semiconductor device. The value of the surface resistance value of the surface of a base material layer can be measured with a resistivity meter, for example.

≪Adhesive layer≫

The thickness of the pressure-sensitive adhesive layer is preferably 1 µm to 500 µm, more preferably 3 µm to 300 µm, still more preferably 5 µm to 100 µm, particularly preferably 7 µm to 75 µm, and most Preferably it is 10 micrometers - 50 micrometers. When the thickness of an adhesive layer exists in the said range, the effect of this invention can be expressed further.

The pressure-sensitive adhesive layer, at 23°C, has a tensile rate of 300 mm/min and a 180-degree peel, the adhesive force to the glass plate is preferably 1 N/25 mm or more, more preferably 5 N/25 mm or more, still more preferably 10N/25mm or more, particularly preferably 12N/25mm or more, and most preferably 15N/25mm or more. The upper limit of the adhesive force to a glass plate in a tensile rate of 300 mm/min and 180 degree peel in 23 degreeC of an adhesive layer is typically 1000 N/25 mm or less, Preferably it is 500 N/25 mm or less, More preferably, it is 500 N/25 mm or less, , more preferably 300N/25mm or less, particularly preferably 200N/25mm or less, and most preferably 100N/25mm or less. If the adhesive force with respect to the glass plate in 300 mm/min of tensile rate in 23 degreeC of an adhesive layer, and a 180 degree peel exists in the said range, the effect of this invention can be expressed further.

The storage elastic modulus at 25°C of the pressure-sensitive adhesive layer is preferably 75 kPa or less, more preferably 70 kPa or less, still more preferably 65 kPa or less, particularly preferably 60 kPa or less, and most preferably 55 kPa or less. The lower limit of the storage elastic modulus at 25°C of the pressure-sensitive adhesive layer is preferably 1 kPa or more, more preferably 5 kPa or more, still more preferably 10 kPa or more, particularly preferably 15 kPa or more, and most preferably 20 kPa or more. to be. When the storage elastic modulus in 25 degreeC of an adhesive layer exists in the said range, the effect of this invention can be expressed further.

The glass transition temperature (Tg) of the pressure-sensitive adhesive layer may be, for example, -80° C. or higher, from the viewpoint that the effect of the present invention can be further expressed, in particular, the obtained protective film can exhibit excellent bending durability. . From a viewpoint of improving the deformability of the adhesive layer with respect to a shearing direction, especially, from a viewpoint in which the protective film obtained can express the outstanding bending durability, Tg becomes like this. Preferably it is designed so that it may become -15 degreeC or less. In some embodiment, Tg of an adhesive layer is, for example, Preferably it is 10 degrees C or less, More preferably, it is 0 degrees C or less, More preferably, it is -10 degrees C or less, More preferably, it is -15 degreeC. or less, particularly preferably -20°C or less, and most preferably -30°C or less. The Tg of the pressure-sensitive adhesive layer is, for example, preferably -80°C or higher (more preferably Tg) from the viewpoint of improving cohesiveness and shape restoration properties, in particular, from the viewpoint that the obtained protective film can exhibit excellent bending durability. -70°C or higher, more preferably -60°C or higher, particularly preferably -50°C or higher).

The pressure-sensitive adhesive layer contains a base polymer. The number of base polymers may be one, and 2 or more types may be sufficient as them. The content of the base polymer in the pressure-sensitive adhesive layer is preferably 20% by weight to 100% by weight, more preferably 30% by weight to 95% by weight, and still more preferably from the viewpoint of further expressing the effect of the present invention. Preferably, it is 40 wt% to 90 wt%, particularly preferably 45 wt% to 85 wt%, and most preferably 50 wt% to 80 wt%.

As a base polymer, any suitable polymer can be employ|adopted in the range which does not impair the effect of this invention. Since the effect of this invention can be expressed further, as a base polymer, Preferably at least 1 sort(s) selected from an acrylic polymer, a rubber-type polymer, a silicone-type polymer, and a urethane-type polymer is mentioned. That is, the pressure-sensitive adhesive layer is preferably an acrylic pressure-sensitive adhesive containing an acrylic polymer, a rubber-based pressure-sensitive adhesive containing a rubber-based polymer, a silicone-based pressure-sensitive adhesive containing a silicone-based polymer, a urethane-based pressure-sensitive adhesive containing a urethane-based polymer At least one selected from. Since the effect of this invention can be expressed further, an adhesive layer, Preferably an acrylic adhesive is included. That is, since the effect of this invention can be expressed further, an adhesive layer contains an acrylic adhesive, and this acrylic adhesive contains an acrylic polymer as a base polymer.

Hereinafter, as a representative example of the pressure-sensitive adhesive that may be included in the pressure-sensitive adhesive layer, the acrylic pressure-sensitive adhesive will be described in detail.

<Acrylic adhesive>

An acrylic adhesive contains an acrylic polymer as a base polymer. The acrylic adhesive may contain the oligomer. The acrylic adhesive may contain tackifying resin. The acrylic adhesive may contain the crosslinking agent.

When the acrylic pressure-sensitive adhesive contains an acrylic polymer, a tackifying resin, and a crosslinking agent, the content ratio of the total amount of the acrylic polymer, tackifying resin, and crosslinking agent to the total amount of the acrylic pressure sensitive adhesive, the effect of the present invention can be further expressed , Preferably it is 95 weight% or more, More preferably, it is 97 weight% or more, More preferably, it is 99 weight% or more.

(Acrylic polymer)

As the acrylic polymer, for example, a polymer of a monomer component (M) containing alkyl (meth)acrylate as a main monomer and further containing a secondary monomer having copolymerizability with the main monomer is preferable. Here, a main monomer means the component which occupies more than 50 weight% of the whole monomer component (M).

An acrylic polymer can be prescribed|regulated as a substance obtained by superposing|polymerizing a monomer component (M) in this way. This is because the acrylic polymer becomes an acrylic polymer when the monomer component (M) causes a polymerization reaction, and it is impossible to directly specify the acrylic polymer by its structure, and it is not practical at all (“impossible/impossible circumstances”) ), the acrylic polymer can be appropriately identified as a "substance" by the regulation of "a substance obtained by polymerizing the monomer component (M)".

As an alkyl (meth)acrylate, the compound represented by following formula (1) can be used suitably, for example.

CH ₂ =C(R ¹ )COOR ² (1)

Here, in the formula (1), R ¹ is a hydrogen atom or a methyl group, and R ² is a chain alkyl group having 1 to 20 carbon atoms (hereinafter, the range of the number of carbon atoms may be expressed as “C1-20”). to be. From the viewpoint of the storage elastic modulus of the pressure-sensitive adhesive layer, R ² is preferably a C1-14 chain alkyl group, more preferably a C2-13 chain alkyl group, and still more preferably a C4-12 chain alkyl group. Here, a chain|strand shape is a meaning including a linear shape and a branched shape.

Examples of the alkyl (meth) acrylate in which R ² is a C1-20 chain alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl ( Meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylic rate, isodecyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, Hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, isostearyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate, etc. can be heard The number of these alkyl (meth)acrylates may be one, and 2 or more types may be sufficient as them.

The alkyl (meth) acrylate is preferably n-butyl acrylate (BA), 2-ethylhexyl acrylate (2EHA), and lauryl (meth) acrylate from the viewpoint that the effect of the present invention can be further expressed. can be heard

Regarding the alkyl (meth) acrylate, since the homopolymer of the alkyl (meth) acrylate having a long-chain alkyl group of C10 or more has a temperature region (plateau region) in which the temperature dependence of viscoelasticity is small at a temperature higher than Tg (plato region), it is a monomer component When used as (M), the temperature dependence of tan δ tends to become small. From this point of view, in one embodiment of the present invention, it is preferable to essentially use an alkyl (meth)acrylate having a C10-16 long-chain alkyl group as the alkyl (meth)acrylate, and a C10-13 long-chain alkyl group. It is more preferable to essentially use an alkyl (meth) acrylate having C12, and it is particularly preferable to essentially use lauryl (meth) acrylate, which is an alkyl (meth) acrylate having a C12 long-chain alkyl group.

The content ratio of the alkyl (meth)acrylate in the total monomer component (M) used for the synthesis of the acrylic polymer is preferably 70% by weight or more from the viewpoint of further expressing the effect of the present invention, more preferably Preferably it is 85 weight% or more, More preferably, it is 90 weight% or more. The upper limit of the content rate of an alkyl (meth)acrylate becomes like this. Preferably it is 99.5 weight% or less, More preferably, it is 99 weight% or less. However, an acrylic polymer may be obtained by superposing|polymerizing only alkyl (meth)acrylate substantially.

As one embodiment of the acrylic polymer, among the monomer components (M), an alkyl (meth)acrylate represented by formula (1), R ¹ is a hydrogen atom or a methyl group, and R ² is an alkyl having a C10-20 chain alkyl group. The content of (meth)acrylate (m1) is preferably 5% by weight to 65% by weight, more preferably 6% by weight to 65% by weight, and still more preferably 7% by weight to 65% by weight. . When the content rate of the alkyl (meth)acrylate (m1) in a monomer component (M) exists in the said range, the effect of this invention can be expressed further. In particular, the protective film obtained can express the outstanding bending durability.

In the alkyl (meth) acrylate represented by formula (1), R ¹ is a hydrogen atom or a methyl group, and R ² is a C10-20 chain alkyl group, the alkyl (meth) acrylate (m1), the effect of the present invention is From the viewpoint of further expression, R ² is preferably a C10-14 chain alkyl group, more preferably a C10-13 chain alkyl group, still more preferably a C10-13 chain alkyl group, particularly preferably is a C12 chain alkyl group, most preferably lauryl acrylate.

As one embodiment of the acrylic polymer, the content rate of 2-ethylhexyl acrylate in the monomer component (M) is preferably 15 wt% to 85 wt%, more preferably 17 wt% to 83 wt% and more preferably 20 wt% to 80 wt%, and particularly preferably 20 wt% to 75 wt%. When the content rate of 2-ethylhexyl acrylate in a monomer component (M) exists in the said range, the effect of this invention can be expressed further. In particular, the protective film obtained can express the outstanding bending durability.

As one embodiment of an acrylic polymer, the content rate of 2-ethylhexyl acrylate in a monomer component (M) exceeds 85 weight%, and 98 weight% or less may be sufficient as it. However, in this embodiment, the content rate of the alkyl (meth)acrylate (m1) in the monomer component (M) becomes like this. Preferably it is less than 5 weight%, More preferably, it is less than 3 weight%, More preferably, less than 1% by weight, particularly preferably less than 0.1% by weight and most preferably substantially 0% by weight.

As one embodiment of the acrylic polymer, the total content of alkyl (meth)acrylate (m1) and 2-ethylhexyl acrylate in the monomer component (M) is preferably 65% by weight to 98% by weight, More preferably, it is 70 weight% - 95 weight%, More preferably, it is 72 weight% - 93 weight%, Especially preferably, it is 75 weight% - 90 weight%. When the total content ratio of alkyl (meth)acrylate (m1) and 2-ethylhexyl acrylate in the monomer component (M) is within the above range, the effect of the present invention can be further expressed. In particular, the protective film obtained can express the outstanding bending durability.

As one embodiment of the acrylic polymer, when the monomer component (M) includes an alkyl (meth) acrylate (m1) and 2-ethylhexyl acrylate, 100 parts by weight of the alkyl (meth) acrylate (m1) The weight ratio of 2-ethylhexyl acrylate is preferably 10 parts by weight to 1000 parts by weight, more preferably 20 parts by weight to 950 parts by weight, particularly preferably 30 parts by weight to 900 parts by weight, and most Preferably it is 30 parts by weight to 880 parts by weight. When the weight ratio of 2-ethylhexyl acrylate to 100 parts by weight of the alkyl (meth)acrylate (m1) is within the above range, the effect of the present invention can be further expressed. In particular, the protective film obtained can express the outstanding bending durability.

As one embodiment of the acrylic polymer, the monomer component (M) is an alkyl (meth)acrylate represented by formula (1), R ¹ is a hydrogen atom or a methyl group, and R ² is an alkyl having a C4-7 chain alkyl group. (meth)acrylate (m2) may be included. As one embodiment of the acrylic polymer, the content rate of the alkyl (meth)acrylate (m2) in the monomer component (M) may be 50% by weight or more, but is preferably less than 50% by weight, more preferably 40 It is weight % or less, More preferably, it is 35 weight% or less, Especially preferably, it is 30 weight% or less, Most preferably, it is 25 weight% or less. When the content rate of the alkyl (meth)acrylate (m2) in a monomer component (M) exists in the said range, the effect of this invention can be expressed further.

It is an alkyl (meth)acrylate represented by Formula (1), R< ¹ > is a hydrogen atom or a methyl group, R< ² > As an alkyl (meth)acrylate (m2) whose C4-7 chain|strand alkyl group is, Preferably it is n-butyl acrylate (BA).

As one embodiment of the acrylic polymer, an acrylic polymer in which less than 50% by weight of the total monomer component (M) is n-butyl acrylate (BA). In this case, the content rate of n-butyl acrylate (BA) in all the monomer components (M) is preferably more than 0 weight% and 48 weight% or less from the point which can further express the effect of this invention. , more preferably 5 wt% to 45 wt%, still more preferably 10 wt% to 43 wt%, particularly preferably 15 wt% to 40 wt%, most preferably 20 wt% to 35 wt% %to be. All the monomer components (M) may further contain 2-ethylhexyl acrylate (2EHA) in the ratio more than n-butyl acrylate (BA).

As one embodiment of an acrylic polymer, 50 weight% or more of all monomer components (M) is n-butyl acrylate (BA), The acrylic polymer is mentioned. In this case, the content ratio of n-butyl acrylate (BA) in all the monomer components (M) is preferably more than 50% by weight and 100% by weight or less from the viewpoint that the effect of the present invention can be further expressed. , more preferably 55 wt% to 95 wt%, still more preferably 60 wt% to 90 wt%, particularly preferably 63 wt% to 85 wt%, most preferably 65 wt% to 80 wt% %to be. All the monomer components (M) may further contain 2-ethylhexyl acrylate (2EHA) in a ratio smaller than n-butyl acrylate (BA).

As one embodiment of the acrylic polymer, an acrylic polymer in which less than 50% by weight of the total monomer component (M) is 2-ethylhexyl acrylate (2EHA) is exemplified. In this case, the content ratio of 2-ethylhexyl acrylate (2EHA) in all the monomer components (M) is preferably more than 0% by weight and not more than 48% by weight from the viewpoint of further expressing the effect of the present invention. and more preferably 5 wt% to 45 wt%, still more preferably 10 wt% to 43 wt%, particularly preferably 15 wt% to 40 wt%, and most preferably 20 wt% to 35 wt% % by weight. All the monomer components (M) may further contain n-butyl acrylate (BA) in a ratio more than 2-ethylhexyl acrylate (2EHA).

As one embodiment of an acrylic polymer, 50 weight% or more of all monomer components (M) is 2-ethylhexyl acrylate (2EHA), The acrylic polymer is mentioned. In this case, the content ratio of 2-ethylhexyl acrylate (2EHA) in all the monomer components (M) is preferably more than 50% by weight and not more than 100% by weight from the viewpoint that the effect of the present invention can be further expressed. and more preferably 55 wt% to 98 wt%, still more preferably 60 wt% to 90 wt%, particularly preferably 63 wt% to 85 wt%, and most preferably 65 wt% to 80 wt% % by weight. All the monomer components (M) may further contain n-butyl acrylate (BA) in a ratio smaller than 2-ethylhexyl acrylate (2EHA).

Other monomers may be copolymerized with the acrylic polymer in the range which does not impair the effect of this invention. Other monomers can be used, for example, for the purpose of introducing a functional group that can serve as a crosslinking origin into the acrylic polymer, improving adhesion, adjusting the glass transition temperature (Tg) of the acrylic polymer, and adjusting adhesive performance.

As other monomers capable of introducing a functional group that can serve as a crosslinking origin into the acrylic polymer or contributing to the improvement of adhesion, for example, a hydroxyl group (OH group)-containing monomer, a carboxyl group-containing monomer, an acid anhydride group-containing monomer, a nitrogen-containing monomer (For example, an amide group containing monomer, an amino group containing monomer, an imide group containing monomer), an epoxy group containing monomer, (meth)acryloylmorpholine, vinyl ethers, etc. are mentioned.

Examples of the other monomer capable of improving the cohesive force and heat resistance of the pressure-sensitive adhesive include sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, cyano group-containing monomers, vinyl esters, aromatic vinyl compounds, and the like, and vinyl esters are preferred. . Specific examples of vinyl esters include vinyl acetate (VAc), vinyl propionate, and vinyl laurate, with vinyl acetate (VAc) being preferred.

The other monomer is preferably at least one selected from the group consisting of a hydroxyl group-containing monomer, a carboxyl group-containing monomer, and a nitrogen-containing monomer from the viewpoint of further exhibiting the effects of the present invention.

The number of "other monomers" may be one, and two or more types may be sufficient as them. The content of other monomers in the total monomer component (M) is preferably 0.001 wt% to 40 wt%, more preferably 0.01 wt% to 40 wt%, and still more preferably 0.1 wt% to 10 wt% and particularly preferably 0.5 wt% to 5 wt%, and most preferably 1 wt% to 3 wt%.

As one embodiment of the acrylic polymer, an acrylic polymer in which a carboxyl group-containing monomer is copolymerized as another monomer is exemplified. Examples of the carboxyl group-containing monomer include acrylic acid (AA), methacrylic acid (MAA), carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid. and the like. Among these, since the effect of this invention can be expressed further, as a carboxy group-containing monomer, Preferably, acrylic acid (AA) and methacrylic acid (MAA) are mentioned, More preferably, it is acrylic acid (AA).

When a carboxyl group-containing monomer is employed as the other monomer, the content of the carboxyl group-containing monomer in the total monomer component (M) is preferably 0.1 wt% to 10 wt% from the viewpoint that the effect of the present invention can be further expressed. , more preferably 0.2 wt% to 8 wt%, still more preferably 0.5 wt% to 5 wt%, particularly preferably 0.7 wt% to 4 wt%, most preferably 1 wt% to 3 wt% %to be.

One embodiment of the acrylic polymer includes an acrylic polymer in which a hydroxyl group-containing monomer is copolymerized as another monomer. As a hydroxyl-containing monomer, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acryl are, for example, hydroxyalkyl (meth)acrylates such as lactate and 4-hydroxybutyl (meth)acrylate; polypropylene glycol mono (meth) acrylate; N-hydroxyethyl (meth)acrylamide; and the like. Among these, as the hydroxyl group-containing monomer, from the viewpoint that the effect of the present invention can be further expressed, a hydroxyalkyl (meth)acrylate in which an alkyl group preferably has a straight chain having 2 to 4 carbon atoms is mentioned, specifically As examples, 2-hydroxyethyl acrylate (HEA) and 4-hydroxybutyl acrylate (4HBA) are mentioned, More preferably, it is 4-hydroxybutyl acrylate (4HBA).

When a hydroxyl group-containing monomer is employed as the other monomer, the content of the hydroxyl group-containing monomer in the total monomer component (M) is preferably 0.001% by weight to 10% by weight from the viewpoint that the effect of the present invention can be further expressed. , more preferably 0.01 wt% to 5 wt%, still more preferably 0.02 wt% to 2 wt%, particularly preferably 0.03 wt% to 1 wt%, most preferably 0.05 wt% to 0.5 wt% %to be.

As one embodiment of the acrylic polymer, an acrylic polymer in which a nitrogen-containing monomer is copolymerized as another monomer is exemplified. Examples of the nitrogen-containing monomer include N-vinyl-2-pyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, nitrogen-containing vinyl monomers such as vinyloxazole, vinylmorpholine, (meth)acryloylmorpholine, N-vinylcarboxylic acid amides, and N-vinylcaprolactam; cyano group-containing acrylic monomers such as acrylonitrile and methacrylonitrile; and the like. Among these, as a nitrogen-containing monomer, from the point which can further express the effect of this invention, Preferably, N-vinyl-2-pyrrolidone is mentioned.

When a nitrogen-containing monomer is employed as the other monomer, the content of the nitrogen-containing monomer in the total monomer component (M) is preferably 0.1% by weight to 50% by weight from the viewpoint of further expressing the effect of the present invention. , more preferably 0.2 wt% to 30 wt%, still more preferably 0.3 wt% to 20 wt%, particularly preferably 0.4 wt% to 15 wt%, most preferably 0.5 wt% to 15 wt% %to be.

The Tg of the base polymer may be, for example, -80°C or higher from the viewpoint that the effect of the present invention can be further expressed, in particular, the obtained protective film can exhibit excellent bending durability. The base polymer (preferably an acrylic polymer) has a Tg, preferably -15°C, from the viewpoint of improving the deformability of the pressure-sensitive adhesive layer in the shear direction, in particular, from the viewpoint that the obtained protective film can exhibit excellent bending durability. It is designed to be below. In some embodiments, the Tg of the base polymer is, for example, preferably -10°C or lower, more preferably -15°C or lower, still more preferably -20°C or lower, still more preferably - 25°C or lower, particularly preferably -40°C or lower, and most preferably -50°C or lower. The Tg of the base polymer is, for example, preferably -70 ° C. or higher (more preferably -70 ° C. or higher, from the viewpoint of improving cohesiveness and shape restoration properties, in particular, from the viewpoint that the obtained protective film can exhibit excellent bending durability. -65°C or higher, more preferably -60°C or higher).

The Tg of the base polymer is a value obtained from the formula of Fox based on the Tg of the homopolymer (homopolymer) of each monomer constituting the base polymer and the weight fraction (copolymerization ratio on a weight basis) of the monomer. say Fox's formula is a relational expression between Tg of the copolymer and the glass transition temperature (Tgi) of a homopolymer obtained by homopolymerizing each of the monomers constituting the copolymer, as described below.

1/Tg=Σ(Wi/Tgi)

In Fox's formula, Tg is the glass transition temperature of the copolymer (unit: K), Wi is the weight fraction of the monomer (i) in the copolymer (copolymerization ratio based on weight), and Tgi is the homopolymer of the monomer (i). represents the glass transition temperature (unit: K) of . As Tg of a homopolymer, it shall employ|adopt the value described in well-known material.

As Tg of a homopolymer, the following values can be used specifically, for example.

2-ethylhexyl acrylate -70℃

n-Butyl acrylate -55℃

Acrylic acid 106℃

2-hydroxyethyl acrylate -15℃

4-hydroxybutyl acrylate -40℃

For Tg of homopolymers other than those exemplified above, numerical values described in "Polymer Handbook" (3rd ed., John Wiley & Sons, Inc., 1989) can be used. When a plurality of numerical values are described in the "Polymer Handbook", a conventional value is adopted. For monomers not described in the "Polymer Handbook", the catalog value of the monomer manufacturer is employed. As the Tg of the homopolymer of the monomer that is not described in the "Polymer Handbook" and the catalog value of the monomer manufacturer is not provided, a value obtained by the measurement method described in Japanese Patent Application Laid-Open No. 2007-51271 is used. do.

As a method of obtaining an acrylic polymer, various polymerization methods known as a synthesis method of an acrylic polymer, such as a solution polymerization method, an emulsion polymerization method, a block polymerization method, and a suspension polymerization method, can be employ|adopted suitably, for example. Among these polymerization methods, a solution polymerization method can be preferably used. As a monomer supply method at the time of performing solution polymerization, the batch input method which supplies the whole quantity of a monomer component at once, a continuous supply (dropping) system, a divided supply (dropping) system, etc. are employable suitably. The polymerization temperature can be appropriately selected depending on the type of monomer and solvent used, the type of polymerization initiator, etc., and is preferably 20°C or higher, more preferably 30°C or higher, still more preferably 40°C or higher, and preferably Preferably it is 170 degrees C or less, More preferably, it is 160 degrees C or less, More preferably, it is 140 degrees C or less. As a method for obtaining the acrylic polymer, photopolymerization performed by irradiating light such as UV (typically performed in the presence of a photopolymerization initiator), or radiation polymerization performed by irradiating radiation such as β-ray or γ-ray with active energy rays You may employ|adopt irradiation polymerization.

As a solvent (polymerization solvent) used for solution polymerization, it can select suitably from arbitrary suitable organic solvents. For example, aromatic compounds, such as toluene (typically aromatic hydrocarbons), acetate esters, such as ethyl acetate, aliphatic or alicyclic hydrocarbons, such as hexane and cyclohexane, etc. are mentioned.

The initiator (polymerization initiator) used for polymerization can be suitably selected from arbitrary suitable polymerization initiators according to the kind of polymerization method. The number of polymerization initiators may be one, and 2 or more types may be sufficient as them. As such a polymerization initiator, For example, Azo type polymerization initiators, such as 2,2'- azobisisobutyronitrile (AIBN); persulfates such as potassium persulfate; peroxide-based initiators such as benzoyl peroxide and hydrogen peroxide; substituted ethane-based initiators such as phenyl-substituted ethane; aromatic carbonyl compounds; and the like. As another example of a polymerization initiator, the redox-type initiator by the combination of a peroxide and a reducing agent is mentioned.

To [ the usage-amount of a polymerization initiator / 100 weight part of all monomer components ], Preferably it is 0.005 weight part - 1 weight part, More preferably, they are 0.01 weight part - 1 weight part.

Mw of the acrylic polymer is preferably 10×10 ⁴ to 500×10 ⁴ , more preferably 10×10 ⁴ to 150×10 ⁴ , and still more preferably 20×10 ⁴ to 75×10 ⁴ , Particularly preferably, it is 35×10 ⁴ to 65×10 ⁴ . Here, Mw means the value of standard polystyrene conversion obtained by GPC (gel permeation chromatography). As a GPC apparatus, model name "HLC-8320GPC" (column: TSKgel GMH-H(S), Tosoh Corporation make) can be used, for example.

(oligomer)

The acrylic pressure-sensitive adhesive may include an oligomer. The number of oligomers may be one, and 2 or more types may be sufficient as them. When the acrylic pressure-sensitive adhesive contains an oligomer, the effect of the present invention can be further expressed. In particular, the protective film obtained can express the outstanding bending durability.

The weight average molecular weight (Mw) of an oligomer becomes like this. Preferably it is 1000-30000, More preferably, it is 1500-10000, More preferably, it is 2000-8000, Especially preferably, it is 2000-5000. By using the oligomer of such a weight average molecular weight (Mw), the adhesiveness and elasticity of an acrylic adhesive sheet can be improved.

As an oligomer, an acryl-type oligomer is preferable at the point which is easy to match with an acryl-type polymer.

The glass transition temperature (Tg) of the acrylic oligomer is preferably 20°C or higher, more preferably 40°C or higher, still more preferably 60°C or higher, particularly preferably 80°C or higher, and most preferably above 100°C. The upper limit of the glass transition temperature (Tg) of the acrylic oligomer is preferably 200°C or less, more preferably 180°C or less, and still more preferably 160°C or less.

The glass transition temperature (Tg) of the acrylic oligomer is calculated from the formula of Fox based on the Tg of the homopolymer (homopolymer) of each monomer constituting the monomer and the weight fraction (copolymerization ratio based on weight) of the monomer. say the value Fox's formula is a relational expression between Tg of the copolymer and the glass transition temperature (Tgi) of a homopolymer obtained by homopolymerizing each of the monomers constituting the copolymer, as shown below.

1/Tg=Σ(Wi/Tgi)

In Fox's formula, Tg is the glass transition temperature of the copolymer (unit: K), Wi is the weight fraction of the monomer (i) in the copolymer (copolymerization ratio based on weight), and Tgi is the homopolymer of the monomer (i). represents the glass transition temperature (unit: K) of . As Tg of a homopolymer, the value described in well-known material can be employ|adopted, for example, the numerical value described in "Polymer Handbook" (3rd ed., John Wiley & Sons, Inc., 1989) can be used. When a plurality of numerical values are described in the "Polymer Handbook", a conventional value is adopted. For monomers not described in the "Polymer Handbook", the catalog value of the monomer manufacturer is employed. As the Tg of the homopolymer of the monomer that is not described in the "Polymer Handbook" and the catalog value of the monomer manufacturer is not provided, a value obtained by the measurement method described in Japanese Patent Application Laid-Open No. 2007-51271 is used. do.

The acrylic oligomer contains an alicyclic alkyl (meth)acrylate as a main constituent monomer component. The number of alicyclic alkyl (meth)acrylates may be one, and 2 or more types may be sufficient as them.

Examples of the alicyclic alkyl (meth) acrylate include cycloalkyl (meth) acrylate such as cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cycloheptyl (meth) acrylate, and cyclooctyl (meth) acrylate. ) acrylates; (meth)acrylic acid esters having a bicyclic aliphatic hydrocarbon ring such as isobornyl (meth)acrylate; Dicyclopentanyl (meth) acrylate, dicyclopentanyloxyethyl (meth) acrylate, tricyclofentanyl (meth) acrylate, 1-adamantyl (meth) acrylate, 2-methyl-2-adamantyl ( and (meth)acrylic acid esters having three or more aliphatic hydrocarbon rings such as meth)acrylate and 2-ethyl-2-adamantyl (meth)acrylate.

The alicyclic alkyl (meth)acrylate is preferably dicyclopentanyl acrylate, dicyclopentanyl methacrylate, cyclohexyl acrylate or cyclohexyl methacrylate from the viewpoint of further exhibiting the effects of the present invention.

The content of the alicyclic alkyl (meth)acrylate with respect to the total amount of the constituent monomer components of the acrylic oligomer is preferably 10% by weight to 99% by weight, more preferably from the viewpoint of further expressing the effect of the present invention. is 30 wt% to 98 wt%, more preferably 40 wt% to 97 wt%, and particularly preferably 50 wt% to 96 wt%.

The acrylic oligomer may contain a chain alkyl (meth) acrylate having a chain alkyl group as a constituent monomer component, and the number of chain alkyl (meth) acrylates having a chain alkyl group may be one or more. Here, a chain|strand shape is a meaning including a linear shape and a branched shape.

The chain alkyl (meth) acrylate is preferably a chain alkyl (meth) acrylate having a chain alkyl group having 1 to 20 carbon atoms, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate ) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) Acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, iso Nonyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate ) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, isostearyl (meth) acrylate, nonadecyl (meth) Acrylate and eicosyl (meth)acrylate are mentioned.

As chain alkyl (meth)acrylate, methyl methacrylate is preferable at the point which can further express the effect of this invention.

The content ratio of the chain alkyl (meth)acrylate with respect to the total amount of the constituent monomer components of the acrylic oligomer is preferably 10% by weight to 90% by weight, more preferably from the viewpoint of further expressing the effect of the present invention. It is 20 weight% - 80 weight%, More preferably, it is 30 weight% - 70 weight%.

The acrylic oligomer may contain (meth)acrylic acid as a structural monomer component, and the number of (meth)acrylic acid may be only 1 type, and 2 or more types may be sufficient as it.

As (meth)acrylic acid, acrylic acid is preferable at the point which can express the effect of this invention further.

The content ratio of (meth)acrylic acid with respect to the total amount of the constituent monomer components of the acrylic oligomer is preferably 0.1% by weight to 20% by weight, more preferably 1% by weight from the viewpoint that the effect of the present invention can be further expressed. to 10 wt%, more preferably 3 wt% to 7 wt%.

An oligomer is obtained by superposing|polymerizing a structural monomer component by various polymerization methods. In the case of superposition|polymerization of an oligomer, you may use arbitrary appropriate additives in the range which does not impair the effect of this invention. As such an additive, a polymerization initiator and a chain transfer agent are mentioned, for example.

The content rate of the oligomer in the acrylic pressure-sensitive adhesive is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 8.0 with respect to 100 weight of the acrylic polymer from the viewpoint of further expressing the effect of the present invention. It is a weight part, More preferably, it is 1.0 weight part - 7.0 weight part, Especially preferably, it is 1.5 weight part - 6.0 weight part.

(Tackifying resin)

An acrylic adhesive can contain tackifying resin at the point which can express the effect of this invention further. Examples of the tackifying resin include rosin-based tackifying resin, terpene-based tackifying resin, hydrocarbon-based tackifying resin, epoxy-based tackifying resin, polyamide-based tackifying resin, elastomer-based tackifying resin, and phenol-based tackifying resin. , a ketone-based tackifying resin, and the like. One type may be sufficient as tackifying resin, and 2 or more types may be sufficient as it.

The amount of the tackifying resin used is preferably 5 parts by weight to 70 parts by weight, more preferably 10 parts by weight to 60 parts by weight with respect to 100 parts by weight of the base polymer from the viewpoint that the effect of the present invention can be further expressed. parts, more preferably 15 parts by weight to 50 parts by weight, still more preferably 20 parts by weight to 45 parts by weight, particularly preferably 25 parts by weight to 40 parts by weight, most preferably 25 parts by weight to 35 parts by weight.

Since tackifying resin can further express the effect of this invention, it is preferable that a softening point contains less than 105 degreeC tackifying resin (TL). Tackifying resin TL can contribute effectively to the improvement of the deformability to the surface direction (shear direction) of an adhesive layer. From the viewpoint of obtaining a higher deformability improving effect, the softening point of the tackifying resin used as the tackifying resin (TL) is preferably 50° C. to 103° C., more preferably 60° C. to 100° C., still more preferably is 65°C to 95°C, particularly preferably 70°C to 90°C, and most preferably 75°C to 85°C.

The softening point of tackifying resin is defined as a value measured based on the softening point test method (round-ball method) prescribed|regulated to JIS K5902 and JIS K2207. Specifically, the sample is melted as quickly as possible at as low a temperature as possible, and the ring placed on a flat metal plate is filled carefully so as not to form bubbles. After cooling, cut off the raised portion from the plane containing the top of the ring with a slightly heated small knife. Next, a support device (annulus) is put in a glass container (heating bath) with a diameter of 85 mm or more and a height of 127 mm or more, and glycerin is injected until it becomes 90 mm or more in depth. Next, the steel ball (diameter 9.5 mm, weight 3.5 g) and the ring filled with the sample are immersed in glycerin so that they do not come into contact with each other, and the temperature of the glycerin is maintained at 20°C±5°C for 15 minutes. Next, a steel ball is placed on the center of the surface of the sample in the ring, and this is placed in a fixed position on the supporter. Next, the distance from the upper end of the ring to the glycerin surface is maintained at 50 mm, a thermometer is placed, and the container is heated with the central position of the mercury sphere of the thermometer at the same height as the center of the ring. The flame of the Bunsen burner used for heating should reach the center of the bottom of the container and the middle of the rim to equalize the heating. In addition, the rate at which the bath temperature rises after reaching 40°C after the start of heating must be 5.0±5°C per minute. The sample gradually softens and flows down from the ring, and the temperature when it finally comes into contact with the bottom plate is read, and this is taken as the softening point. Two or more softening points are measured simultaneously, and the average value is employ|adopted.

As a usage-amount of tackifying resin (TL), from the point which can express the effect of this invention further, with respect to 100 weight part of base polymers, Preferably it is 5 weight part - 50 weight part, More preferably, it is 10 weight part to 45 parts by weight, more preferably 15 to 40 parts by weight, particularly preferably 20 to 35 parts by weight, and most preferably 25 to 32 parts by weight.

As tackifying resin (TL), the 1 type(s) or 2 or more types suitably selected from the thing with a softening point being less than 105 degreeC among the tackifying resins illustrated above can be employ|adopted. Tackifying resin (TL), Preferably a rosin-type resin is included.

As rosin-type resin which can be suitably employ|adopted as tackifying resin (TL), rosin esters, such as unmodified rosin ester and modified rosin ester, are mentioned, for example. As modified rosin ester, hydrogenated rosin ester is mentioned, for example.

Since tackifying resin (TL) can further express the effect of this invention, Preferably, hydrogenated rosin ester is included. As hydrogenated rosin ester, a softening point is from the point which can further express the effect of this invention, Preferably it is less than 105 degreeC, More preferably, it is 50 degreeC - 100 degreeC, More preferably, it is 60 degreeC - 90 degreeC and particularly preferably at 70°C to 85°C, and most preferably at 75°C to 85°C.

Tackifying resin (TL) may contain the non-hydrogenated rosin ester. Here, the non-hydrogenated rosin ester is a concept that comprehensively points to things other than hydrogenated rosin esters among the above-mentioned rosin esters. Examples of the non-hydrogenated rosin ester include unmodified rosin ester, disproportionated rosin ester, and polymerized rosin ester.

As the non-hydrogenated rosin ester, the softening point is preferably less than 105° C., more preferably 50° C. to 100° C., further preferably 60° C. to 90° C. from the viewpoint of further expressing the effect of the present invention. °C, particularly preferably from 70 °C to 85 °C, and most preferably from 75 °C to 85 °C.

Tackifying resin (TL) may contain other tackifying resin in addition to rosin-type resin. As other tackifying resin, the 1 type(s) or 2 or more types suitably selected from the thing of less than 105 degreeC of softening point among the tackifying resins illustrated above can be employ|adopted. Tackifying resin (TL) may contain rosin-type resin and terpene resin, for example.

The content rate of the rosin-type resin to the whole tackifying resin (TL) becomes from the point which can express the effect of this invention further, Preferably it exceeds 50 weight%, More preferably, it is 55 weight% - 100 weight% %, more preferably 60 wt% to 99 wt%, particularly preferably 65 wt% to 97 wt%, and most preferably 75 wt% to 97 wt%.

Tackifying resin combines tackifying resin (TL) and the softening point 105 degreeC or more (preferably 105 degreeC - 170 degreeC) from the point which can express the effect of this invention further, tackifying resin (TH) may be included.

As tackifying resin (TH), the 1 type(s) or 2 or more types suitably selected from the thing of a softening point 105 degreeC or more among the tackifying resins illustrated above can be employ|adopted. The tackifying resin (TH) may contain at least one selected from a rosin-based tackifying resin (eg, rosin esters) and a terpene-based tackifying resin (eg, terpene phenol resin).

(crosslinking agent)

The acrylic pressure-sensitive adhesive may contain a crosslinking agent. The number of crosslinking agents may be one, and 2 or more types may be sufficient as them. By use of a crosslinking agent, moderate cohesive force can be provided to an acrylic adhesive. The crosslinking agent can also help control the shift distance and the return distance in the holding force test. The acrylic adhesive containing a crosslinking agent can be obtained by forming an adhesive layer using the adhesive composition containing this crosslinking agent, for example. The crosslinking agent may be included in the acrylic pressure-sensitive adhesive in the form after the crosslinking reaction, in the form before the crosslinking reaction, in a partially crosslinked form, in an intermediate or complex form thereof, and the like. A crosslinking agent is typically contained in the acrylic adhesive only in the form after a crosslinking reaction.

The amount of the crosslinking agent used is preferably 0.005 parts by weight to 10 parts by weight, more preferably 0.008 parts by weight to 8 parts by weight, based on 100 parts by weight of the base polymer from the viewpoint of further expressing the effects of the present invention. , More preferably 0.01 parts by weight to 7 parts by weight, more preferably 0.01 parts by weight to 5 parts by weight, still more preferably 0.01 parts by weight to 4 parts by weight, particularly preferably 0.01 parts by weight to 3 parts by weight parts, and most preferably 0.01 to 2 parts by weight.

Examples of the crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, a silicone crosslinking agent, an oxazoline crosslinking agent, an aziridine crosslinking agent, a silane crosslinking agent, an alkyletherified melamine crosslinking agent, a metal chelate crosslinking agent, a peroxide, and a crosslinking agent such as a polyfunctional monomer. etc. are mentioned, From the point which can further express the effect of this invention, Preferably they are an isocyanate type crosslinking agent, an epoxy type crosslinking agent, a peroxide, and a polyfunctional monomer, More preferably, they are an isocyanate type crosslinking agent, a peroxide, a polyfunctional monomer. to be.

As the isocyanate-based crosslinking agent, a compound having two or more isocyanate groups (including an isocyanate regenerated functional group in which the isocyanate group is temporarily protected by a blocking agent or quantization or the like) can be used in one molecule. As an isocyanate type crosslinking agent, For example, aromatic isocyanate, such as tolylene diisocyanate and xylene diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; aliphatic isocyanates such as hexamethylene diisocyanate; and the like.

As an isocyanate type crosslinking agent, More specifically, For example, Lower aliphatic polyisocyanate, such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; aromatic diisocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, and polymethylene polyphenyl isocyanate; Trimethylolpropane/tolylene diisocyanate trimer adduct (For example, Tosoh Corporation make, trade name Coronate L), Trimethylolpropane/hexamethylene diisocyanate trimer adduct (For example, Tosoh Corporation make, trade name: Coro Nate HL) and isocyanate adducts, such as the isocyanurate body of hexamethylene diisocyanate (For example, the Tosoh Corporation make, brand name: Coronate HX); Trimethylolpropane adduct of xylylene diisocyanate (For example, Mitsui Chemicals, trade name: Takenate D110N), and trimethylolpropane adduct of xylylene diisocyanate (For example, Mitsui Chemicals, trade name) : Takenate D120N), a trimethylolpropane adduct of isophorone diisocyanate (for example, Mitsui Chemicals, trade name: Takenate D140N), a trimethylolpropane adduct of hexamethylene diisocyanate (for example, Mitsui) The chemical company make, brand name: Takenate D160N); polyether polyisocyanate, polyester polyisocyanate, and adducts of these and various polyols; polyisocyanates polyfunctionalized by an isocyanurate bond, a biuret bond, an allophanate bond, or the like; and the like. Among these, aromatic isocyanate and alicyclic isocyanate are preferable at the point which is compatible with deformability and cohesion force in good balance.

The amount of the isocyanate-based crosslinking agent to be used is preferably 0.005 parts by weight to 10 parts by weight, more preferably 0.008 parts by weight to 8 parts by weight with respect to 100 parts by weight of the base polymer from the viewpoint that the effect of the present invention can be further expressed. parts, more preferably 0.01 parts by weight to 7 parts by weight, still more preferably 0.01 parts by weight to 5 parts by weight, still more preferably 0.01 parts by weight to 4 parts by weight, particularly preferably 0.01 parts by weight to 3 parts by weight, and most preferably 0.01 to 2 parts by weight.

When the monomer component constituting the acrylic polymer contains a hydroxyl group-containing monomer, the weight ratio of the isocyanate-based crosslinking agent/hydroxyl group-containing monomer is preferably greater than 20 and less than 50 from the viewpoint that the effect of the present invention can be further expressed. , More preferably, it is 22-45, More preferably, it is 25-40, Especially preferably, it is 27-40, Most preferably, it is 30-35.

When the acrylic pressure-sensitive adhesive contains a tackifying resin (TL) having a softening point of 105° C. or less, the weight ratio of the tackifying resin (TL)/isocyanate cross-linking agent is preferably 2 from the viewpoint of further expressing the effects of the present invention. More than 15 and less than 15, More preferably, it is 5-13, More preferably, it is 7-12, Especially preferably, it is 7-11.

As the epoxy-based crosslinking agent, a polyfunctional epoxy compound having two or more epoxy groups in one molecule can be used. As the epoxy-based crosslinking agent, for example, N,N,N',N'-tetraglycidyl-m-xylenediamine, diglycidylaniline, 1,3-bis(N,N-diglycidylaminomethyl) ) Cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, poly Propylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane Polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol- S-diglycidyl ether, an epoxy resin having two or more epoxy groups in the molecule, and the like. As a commercial item of an epoxy-type crosslinking agent, the Mitsubishi Gas Chemical company brand name "tetrad C", "tetrad X", etc. are mentioned, for example.

The amount of the epoxy-based crosslinking agent to be used is preferably 0.005 parts by weight to 10 parts by weight, preferably 0.005 parts by weight to 10 parts by weight, based on 100 parts by weight of the base polymer from the viewpoint that the effect of the present invention can be further expressed. and more preferably 0.008 parts by weight to 8 parts by weight, still more preferably 0.01 parts by weight to 7 parts by weight, still more preferably 0.01 parts by weight to 5 parts by weight, still more preferably 0.01 parts by weight to 4 parts by weight part by weight, particularly preferably 0.01 part by weight to 3 parts by weight, and most preferably 0.01 part by weight to 2 parts by weight.

Examples of the polyfunctional monomer include 1,6-hexanediol di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, and propylene glycol di(meth)acryl. rate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, allyl (meth) acrylate, vinyl ( difunctional monomers such as meth)acrylate and divinylbenzene; Trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate monomer; In addition, epoxy acrylate, polyester acrylate, urethane acrylate, etc.; and the like. Among these, preferred examples of the polyfunctional monomer include 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

The amount of the polyfunctional monomer used is preferably 0.005 parts by weight to 10 parts by weight, more preferably 0.008 parts by weight to 8 parts by weight, based on 100 parts by weight of the base polymer, from the viewpoint of further expressing the effects of the present invention. parts, more preferably 0.01 parts by weight to 7 parts by weight, still more preferably 0.01 parts by weight to 5 parts by weight, still more preferably 0.01 parts by weight to 4 parts by weight, particularly preferably 0.01 parts by weight to 3 parts by weight, and most preferably 0.01 to 2 parts by weight. In addition, a polyfunctional monomer may be added with respect to the so-called prepolymer which has a low polymerization rate as a base polymer, and in this case, a prepolymer becomes a base polymer.

(Other Ingredients)

The acrylic pressure-sensitive adhesive may contain various additives common in the field of pressure-sensitive adhesives, such as leveling agents, crosslinking aids, plasticizers, softeners, fillers, antistatic agents, anti-aging agents, ultraviolet absorbers, antioxidants, and light stabilizers, if necessary. About these various additives, a conventionally well-known thing can be used by a conventional method.

≪Antistatic layer≫

The protective film by embodiment of this invention may have an antistatic layer in the surface on the opposite side to the surface which has an adhesive layer of a base material layer. When the protective film according to the embodiment of the present invention has an antistatic layer on the surface on the opposite side to the surface having the pressure-sensitive adhesive layer of the base layer, the charging of the protective film itself can be suppressed, and dust is less likely to be adsorbed, a preferred aspect becomes

Examples of the antistatic layer include a method of applying an antistatic resin containing an antistatic agent and a resin component, a conductive polymer, and a conductive resin containing a conductive substance, and a method of depositing or plating a conductive substance.

As an antistatic agent contained in antistatic resin, For example, the cationic type antistatic agent which has cationic functional groups, such as a quaternary ammonium salt, a pyridinium salt, 1st, 2nd, 3rd amino group; anionic antistatic agents having anionic functional groups such as sulfonates, sulfate salts, phosphonates, and phosphoric acid ester salts; positive antistatic agents such as alkylbetaine and derivatives thereof, imidazoline and derivatives thereof, alanine and derivatives thereof; Nonionic antistatic agents, such as amino alcohol and its derivative(s), glycerol and its derivative(s), polyethyleneglycol, and its derivative(s); an ion conductive polymer obtained by superposing|polymerizing or copolymerizing the monomer which has the said cationic type, an anionic type, and amphoteric ion type ion conductive group; and the like. The number of these antistatic agents may be one, and 2 or more types may be sufficient as them.

Examples of the cationic antistatic agent include quaternary ammonium groups such as alkyltrimethylammonium salt, acyloylamidopropyltrimethylammonium methosulfate, alkylbenzylmethylammonium salt, choline acyl chloride, and polydimethylaminoethyl methacrylate (meth ) acrylate copolymers; styrene copolymers having a quaternary ammonium group such as polyvinylbenzyltrimethylammonium chloride; diallylamine copolymers having a quaternary ammonium group such as polydiallyldimethylammonium chloride; and the like. The number of these antistatic agents may be one, and 2 or more types may be sufficient as them.

Examples of the anionic antistatic agent include alkylsulfonate, alkylbenzenesulfonate, alkylsulfate, alkylethoxysulfate, alkylphosphate, and sulfonic acid group-containing styrene copolymer. The number of these antistatic agents may be one, and 2 or more types may be sufficient as them.

Examples of the amphoteric antistatic agent include alkyl betaine, alkyl imidazolium betaine, and carbobetaine graft copolymer. The number of these antistatic agents may be one, and 2 or more types may be sufficient as them.

Examples of the nonionic antistatic agent include fatty acid alkylolamide, di(2-hydroxyethyl)alkylamine, polyoxyethylene alkylamine, fatty acid glycerin ester, polyoxyethylene glycol fatty acid ester, sorbitan fatty acid ester, poly Oxysorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ether, polyethylene glycol, polyoxyethylene diamine, a copolymer containing polyether, polyester and polyamide, methoxy polyethylene glycol (meth) acrylate and the like. The number of these antistatic agents may be one, and 2 or more types may be sufficient as them.

Examples of the conductive polymer include polyaniline, polypyrrole, and polythiophene. The number of these conductive polymers may be one, and 2 or more types may be sufficient as them.

Examples of the 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, iodide. and copper and alloys or mixtures thereof. The number of these electroconductive substances may be one, and 2 or more types may be sufficient as them.

As a resin component used for an antistatic resin and an electroconductive resin, general-purpose resins, such as a polyester resin, an acrylic resin, a polyvinyl resin, a urethane resin, a melamine resin, and an epoxy resin, are used, for example. In addition, in the case of a polymer type antistatic agent, it is not necessary to contain a resin component. In addition, as a component of the antistatic resin, as a crosslinking agent, a methylolated or alkylolated melamine-based compound, a urea-based compound, a glyoxal-based compound, an acrylamide-based compound; epoxy compounds; isocyanate compounds; It is also possible to contain the like.

The antistatic layer is formed by, for example, diluting the above-described antistatic resin, conductive polymer, conductive resin, etc. with a solvent such as an organic solvent or water, applying the coating solution to a substrate or the like, and drying it.

Examples of the diluted solution used for forming the antistatic layer include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexanone, n-hexane, toluene, xylene, methanol, ethanol, n-propanol, isopropanol, water, and the like. The number of these solvents may be one, and 2 or more types may be sufficient as them.

As for the coating method in formation of an antistatic layer, arbitrary appropriate application|coating methods are used suitably. Examples of such a coating method include roll coat, gravure coat, reverse coat, roll brush, spray coat, air knife coat, impregnation, and curtain coat.

As a method of vapor deposition or plating of an electroconductive substance, any suitable method is used suitably. Examples of such a method include vacuum vapor deposition, sputtering, ion plating, chemical vapor deposition, spray thermal decomposition, chemical plating, and electroplating.

Any suitable thickness can be employ|adopted for the thickness of an antistatic layer in the range which does not impair the effect of this invention. Since the effect of this invention can be expressed further, the thickness of an antistatic layer becomes like this. Preferably it is 0.001 micrometer - 5 micrometers, More preferably, they are 0.005 micrometer - 1 micrometer.

≪Top coat layer≫

The protective film by embodiment of this invention may have a topcoat layer in the surface on the opposite side to the surface which has an adhesive layer of a base material layer. The top coat layer preferably contains a binder, and more preferably contains a binder and a lubricant. When the protective film according to the embodiment of the present invention has a top coat layer, the scratch resistance of the protective film is improved and it is a preferable aspect.

<Binder>

Any suitable resin can be employ|adopted as a binder in the range which does not impair the effect of this invention. As such resin, it is at least 1 sort(s) selected from the group which preferably consists of a polyester resin and a urethane resin at the point which can further express the effect of this invention.

(polyester resin)

When a polyester resin is contained in a binder, only 1 type may be sufficient as this polyester resin, and 2 or more types may be sufficient as it.

The polyester resin is preferably a resin containing polyester as a main component. The content rate of polyester in a polyester resin becomes like this. Preferably it is more than 50 weight%, More preferably, it is 75 weight% or more, More preferably, it is 90 weight% or more.

The polyester is preferably selected from polyhydric carboxylic acids having two or more carboxyl groups in one molecule (preferably dicarboxylic acids) and derivatives thereof (anhydrides, esters, halides, etc. of polyhydric carboxylic acids) A structure in which at least one compound (polyhydric carboxylic acid component) and at least one compound (polyhydric alcohol component) selected from polyhydric alcohols (preferably diols) having two or more hydroxyl groups in one molecule are condensed has

Examples of the compound that can be employed as the polyhydric carboxylic acid component include oxalic acid, malonic acid, difluoromalonic acid, alkylmalonic acid, succinic acid, tetrafluorosuccinic acid, alkylsuccinic acid, (±)-malic acid, and meso-tartaric acid. , itaconic acid, maleic acid, methyl maleic acid, fumaric acid, methyl fumaric acid, acetylenedicarboxylic acid, glutaric acid, hexafluoroglutaric acid, methylglutaric acid, glutaconic acid, adipic acid, dithioadipic acid , methyl adipic acid, dimethyl adipic acid, tetramethyl adipic acid, methylene adipic acid, muconic acid, galactaric acid, pimelic acid, suberic acid, perfluorosuberic acid, 3,3,6,6 aliphatic dicarboxylic acids such as tetramethylsuberic acid, azelaic acid, sebacic acid, perfluorosebacic acid, brassylic acid, dodecyldicarboxylic acid, tridecyldicarboxylic acid, and tetradecyldicarboxylic acid; Cycloalkyldicarboxylic acid (eg 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,4-(2-norbornene)dicarboxylic acid, 5 -alicyclic dicarboxylic acids such as norbornene-2,3-dicarboxylic acid (hymic acid), adamantane dicarboxylic acid, spiroheptane dicarboxylic acid, phthalic acid, isophthalic acid, dithioisophthalic acid, Methylisophthalic acid, dimethylisophthalic acid, chloroisophthalic acid, dichloroisophthalic acid, terephthalic acid, methylterephthalic acid, dimethylterephthalic acid, chloroterephthalic acid, bromoterephthalic acid, naphthalenedicarboxylic acid, oxofluorenedicarboxylic acid, anthracenedicarboxylic acid , biphenyl dicarboxylic acid, biphenylenedicarboxylic acid, dimethylbiphenylenedicarboxylic acid, 4,4"-p-terephenylenedicarboxylic acid, 4,4"-p-quwarel Phenyldicarboxylic acid, bibenzyldicarboxylic acid, azobenzenedicarboxylic acid, homophthalic acid, phenylene diacetic acid, phenylenedipropionic acid, naphthalenedicarboxylic acid, naphthalenedipropionic acid, biphenyldiacetic acid, biphenyldipropionic acid , 3,3'-[4,4'-(methylenedi-p-biphenylene)dipropionic acid, 4,4'-bibenzyldiacetic acid, 3,3'(4,4'-bibenzyl)dipropionic acid Aromatic dicarboxylic acids such as , oxydi-p-phenylene diacetic acid; Acid anhydrides of any of the above polyhydric carboxylic acids; Esters of any of the above polyhydric carboxylic acids (eg, alkyl esters, monoesters) ;

As a suitable example of the compound which can be employ|adopted as a polyhydric carboxylic acid component, Aromatic dicarboxylic acids, such as terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, and its acid anhydride; aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, succinic acid, fumaric acid, maleic acid, hymic acid, and 1,4-cyclohexanedicarboxylic acid and acid anhydrides thereof; lower alkyl esters of the above dicarboxylic acids (eg, esters with monoalcohols having 1 to 3 carbon atoms); and the like.

Examples of the compound that can be employed as the polyhydric alcohol component include ethylene glycol, propylene glycol, 1,2-propanediol, 1,3-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, Diols such as 3-propanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, xylylene glycol, hydrogenated bisphenol A, and bisphenol A can be heard Other examples include alkylene oxide adducts (eg, ethylene oxide adducts, propylene oxide adducts, etc.) of these compounds.

The polyester resin preferably contains water-dispersible polyester, and more preferably contains water-dispersible polyester as a main component. Such water-dispersible polyester is, for example, a polyester with improved water dispersibility by introducing a hydrophilic functional group (for example, at least one selected from hydrophilic functional groups such as sulfonic acid metal base, carboxyl group, ether group, and phosphoric acid group) in the polymer. can As such, as a method of introducing a hydrophilic functional group into the polymer, for example, a method of copolymerizing a compound having a hydrophilic functional group, polyester or a precursor thereof (for example, a polyhydric carboxylic acid component, a polyhydric alcohol component, an oligomer thereof, etc.) ) to generate a hydrophilic functional group, any suitable method may be appropriately employed. As preferable water-dispersible polyester, the polyester (copolymerization polyester) in which the compound which has a hydrophilic functional group was copolymerized is mentioned.

The polyester resin used as a binder may have saturated polyester as a main component, and may have unsaturated polyester as a main component. The polyester resin, Preferably, the main component is saturated polyester, More preferably, it is saturated polyester (for example, saturated copolymer polyester) to which water dispersibility was provided. Such a polyester resin (a polyester resin that may be prepared in the form of an aqueous dispersion) can be synthesized by any suitable method, or a commercial item can be easily obtained.

The molecular weight of the polyester resin is a weight average molecular weight (Mw) in terms of standard polystyrene measured by gel permeation chromatography (GPC), preferably 0.5×10 ⁴ to 15×10 ⁴ , more preferably 1× 10 ⁴ to 6×10 ⁴ .

The glass transition temperature (Tg) of the polyester resin is preferably 0°C to 100°C, more preferably 10°C to 80°C.

(urethane-based resin)

When a urethane-type resin is contained in a binder, 1 type may be sufficient as this urethane-type resin, and 2 or more types may be sufficient as it.

The urethane-based resin is preferably a urethane-based resin obtained by curing a composition containing a polyol (A) and a polyfunctional isocyanate compound (B).

As a polyol (A), only 1 type may be sufficient and 2 or more types may be sufficient as it.

As the polyol (A), any appropriate polyol can be employed as long as it is a polyol having two or more OH groups. Examples of the polyol (A) include a polyol having two OH groups (diol), a polyol having three OH groups (triol), a polyol having four OH groups (tetraol), and a polyol having five OH groups (penta ol), a polyol having 6 OH groups (hexanol), and the like.

As polyol (A), Preferably, glycols, such as ethylene glycol and propylene glycol which have two or more OH groups, are employ|adopted as an essential component. When glycol is employed as an essential component in this way, for example, it is possible to provide a urethane-based cured resin that is excellent in the strength of the coating film after curing and is excellent in adhesion to a substrate and retention of an additive material. The content of glycol in the polyol (A) is preferably 30 wt% to 100 wt%, more preferably 50 wt% to 100 wt%, still more preferably 70 wt% to 100 wt%, further It is preferably 90% by weight to 100% by weight, particularly preferably 95% to 100% by weight, and most preferably substantially 100% by weight.

Examples of the polyol (A) include ethylene glycol, diethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-butyl- 2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,9- Nonanediol, 2-methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, hexanetriol, polyethylene glycol, polypropylene glycol, polyester polyol, Polyether polyol, polycaprolactone polyol, polycarbonate polyol, a castor oil-type polyol, etc. are mentioned.

As a polyester polyol, it can obtain by the esterification reaction of a polyol component and an acid component, for example.

Examples of the acid component include succinic acid, methylsuccinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanoic acid, 1,14-tetradecanedioic acid, dimer acid, 2-methyl-1, 4-cyclohexanedicarboxylic acid, 2-ethyl-1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 4,4' -biphenyldicarboxylic acid, these acid anhydrides, etc. are mentioned.

Examples of the polyether polyol include water, low molecular weight polyols (propylene glycol, ethylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc.), bisphenols (bisphenol A, etc.), dihydroxybenzene (catechol, resorcin, polyether polyol obtained by addition polymerization of alkylene oxides, such as ethylene oxide, propylene oxide, and a butylene oxide, using hydroquinone etc.) etc. as an initiator. Specifically, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. are mentioned, for example.

Examples of the polycaprolactone polyol include caprolactone-based polyesterdiol obtained by ring-opening polymerization of cyclic ester monomers such as ε-caprolactone and σ-valerolactone.

As a polycarbonate polyol, For example, polycarbonate polyol obtained by making the said polyol component and phosgene polycondensate; The above polyol component and dicarbonate such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, ethyl butyl carbonate, ethylene carbonate, propylene carbonate, diphenyl carbonate, and dibenzyl carbonate polycarbonate polyols obtained by transesterifying esters; Copolymerization polycarbonate polyol obtained by using together 2 or more types of said polyol component; a polycarbonate polyol obtained by esterifying the various polycarbonate polyols with a carboxyl group-containing compound; polycarbonate polyols obtained by etherifying the various polycarbonate polyols with a hydroxyl group-containing compound; a polycarbonate polyol obtained by transesterifying the various polycarbonate polyols with an ester compound; polycarbonate polyols obtained by transesterifying the various polycarbonate polyols with a hydroxyl group-containing compound; polyester-based polycarbonate polyols obtained by polycondensation reaction of the various polycarbonate polyols and dicarboxylic acid compounds; copolymerized polyether-based polycarbonate polyols obtained by copolymerizing the above various polycarbonate polyols and alkylene oxides; and the like.

Examples of the castor oil-based polyol include a castor oil-based polyol obtained by reacting a castor oil fatty acid with the polyol component. Specific examples thereof include castor oil-based polyols obtained by reacting castor oil fatty acids with polypropylene glycol.

The number of polyfunctional isocyanate compounds (B) may be one, and 2 or more types may be sufficient as them.

As the polyfunctional isocyanate compound (B), any appropriate polyfunctional isocyanate compound that can be used in the urethanation reaction can be employed. As such a polyfunctional isocyanate compound (B), a polyfunctional aliphatic type isocyanate compound, polyfunctional alicyclic type isocyanate, a polyfunctional aromatic type isocyanate compound, etc. are mentioned, for example.

Examples of the polyfunctional aliphatic isocyanate compound include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene. Diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, etc. are mentioned.

Examples of the polyfunctional alicyclic isocyanate compound include 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate. and hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated tetramethylxylylene diisocyanate.

Examples of the polyfunctional aromatic diisocyanate compound include phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, and 4,4'-diphenyl Methane diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, xylylene diisocyanate, etc. are mentioned. have.

As a polyfunctional isocyanate compound (B), the trimethylol propane adduct body of the above various polyfunctional isocyanate compounds, the biuret body which reacted with water, the trimer which has an isocyanurate ring, etc. are mentioned. Moreover, you may use these together.

The content of the polyfunctional isocyanate compound (B) is preferably 5 wt% to 60 wt%, more preferably 8 wt% to 60 wt%, relative to the polyol (A). and more preferably 10% by weight to 60% by weight. By adjusting the content rate of a polyfunctional isocyanate compound (B) within the said range, the effect of this invention can be expressed further.

A urethane-type resin is typically obtained by hardening|curing the composition containing a polyol (A) and a polyfunctional isocyanate compound (B). In such a composition, any appropriate other components other than the polyol (A) and the polyfunctional isocyanate compound (B) may be included in the range that does not impair the effects of the present invention. Such other components include, for example, catalysts, resin components other than polyurethane-based resins, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, thin water, softeners, plasticizers, antioxidants, conductive agents, antioxidants, A ultraviolet absorber, a light stabilizer, a surface lubricant, a leveling agent, a corrosion inhibitor, a heat-resistant stabilizer, a polymerization inhibitor, a lubricant, a solvent, etc. are mentioned.

As a method for obtaining a urethane-based resin by curing a composition containing a polyol (A) and a polyfunctional isocyanate compound (B), a urethanation reaction method using bulk polymerization, solution polymerization, etc. In the range that does not impair the effects of the present invention Any suitable method may be employed.

(Other resins)

The top coat layer, as a binder, as long as the performance of the protective film is not significantly impaired, resins other than polyester resins and urethane resins (eg, acrylic resins, acrylic-styrene resins, acrylic-silicone resins, silicone resins). , at least one resin selected from polysilazane resin, fluororesin, and polyolefin resin) may be further contained. As a preferred embodiment of the top coat layer, the binder of the top coat layer substantially contains at least one selected from the group consisting of polyester resins and urethane resins, and selected from the group consisting of polyester resins and urethane resins occupying the binder. The proportion of at least one used is preferably 98% by weight to 100% by weight, more preferably 99% by weight to 100% by weight, and still more preferably 99.5% by weight to 100% by weight. The proportion of the binder in the entire topcoat layer is preferably 15 wt% to 95 wt%, and more preferably 25 wt% to 80 wt%.

<Lubrication>

As a lubricant, it is preferable to contain the ester of a higher fatty acid and a higher alcohol (Hereinafter, it may call a "wax ester").

A "higher fatty acid" is preferably a carboxylic acid having 8 or more carbon atoms, more preferably 10 or more, and still more preferably 10 to 40 carbon atoms. The carboxylic acid is preferably monovalent carboxylic acid.

The "higher alcohol" is preferably an alcohol having 6 or more carbon atoms, more preferably 10 or more, and still more preferably 10 to 40. Alcohol, Preferably it is monohydric or dihydric alcohol, More preferably, it is monohydric alcohol.

The top coat layer having a composition including such a wax ester in combination with the above-mentioned binder is hardly whitened even when maintained under a high temperature and high humidity condition. Therefore, the protective film provided with the base material which has such a topcoat layer can be made into a thing with higher appearance quality.

As a reason for realizing the excellent whitening resistance (for example, the property that whitening is hard to be maintained even if it maintains at high temperature and high humidity conditions) by the top coat layer of the said composition, the following reasons are considered, for example. That is, it is estimated that the silicone-based lubricant used conventionally exhibits the function of imparting slipperiness to the surface of the topcoat layer by bleeding. However, the degree of bleed tends to fluctuate in such silicone-based lubricants depending on differences in storage conditions (temperature, humidity, aging, etc.). For this reason, for example, when it maintains under normal storage conditions (for example, 25 degreeC, 50%RH), moderate slidability over a comparatively long period (for example, about 3 months) from immediately after manufacture of a protective film. If the usage-amount of a silicone lubricant is set so that this may be obtained, when this protective film is stored in high temperature and high humidity conditions (for example, 60 degreeC, 95%RH) for 2 weeks, the bleed of a lubricant will advance excessively. There exists a possibility that the silicone type lubricant which bleeds excessively in this way may whiten a top coat layer (and thus a protective film).

As a preferred embodiment of the top coat layer, a specific combination of a wax ester as a lubricant and a polyester resin as a binder is employed. According to the combination of the lubricant and the binder, the degree of bleed of the wax ester from the top coat layer is hardly affected by the storage conditions. Thereby, the whitening resistance of a protective film can be improved.

As the wax ester, one or more of the compounds represented by the general formula (W) can be preferably employed.

X-COO-Y (W)

X and Y in formula (W) are each independently, Preferably it is a C10-40 hydrocarbon group, The carbon atom number becomes like this. More preferably, it is 10-35, More preferably, it is 14-35. and particularly preferably 20 to 32. When the number of carbon atoms is too small, there is a fear that the effect of imparting slidability to the topcoat layer is insufficient. A saturated hydrocarbon group may be sufficient as the said hydrocarbon group, and an unsaturated hydrocarbon group may be sufficient as it. The hydrocarbon group is preferably a saturated hydrocarbon group. In addition, the hydrocarbon group may have a structure including an aromatic ring, a structure not including an aromatic ring (aliphatic hydrocarbon group), or a hydrocarbon group (alicyclic hydrocarbon group) having a structure including an aliphatic ring, A chain (including linear and branched) hydrocarbon groups may be used.

As the wax ester, X and Y in the formula (W) are each independently a compound preferably a chain alkyl group having 10 to 40 carbon atoms, more preferably a linear alkyl group having 10 to 40 carbon atoms. is a compound. Specific examples of such a compound include, for example, melicyl serotate (CH ₃ (CH ₂ ) ₂₄ COO(CH ₂ ) ₂₉ CH ₃ ), melicyl palmitate (CH ₃ (CH ₂ ) ₁₄ COO(CH ₂ ) ₂₉ ) CH ₃ ), cetyl palmitate (CH ₃ (CH ₂ ) ₁₄ COO(CH ₂ ) ₁₅ CH ₃ ), stearyl stearate (CH ₃ (CH ₂ ) ₁₆ COO(CH ₂ ) ₁₇ CH ₃ ), etc. can

The wax ester has a melting point of preferably 50°C or higher, more preferably 60°C or higher, still more preferably 70°C or higher, and particularly preferably 75°C or higher. With this wax ester, higher whitening resistance can be realized. It is preferable that melting|fusing point of wax ester is 100 degrees C or less. Such wax esters have a high effect of imparting slidability, so that a topcoat layer having higher scratch resistance can be formed. It is preferable that melting|fusing point of a wax ester is 100 degrees C or less, also from the point of being easy to prepare the aqueous dispersion of a wax ester. As such a wax ester, for example, melicyl cerate can be preferably employed.

As a raw material for the top coat layer, a natural wax containing such a wax ester can be used. As such a natural wax, the content ratio of the wax esters (the sum of the content ratios when two or more types of wax esters are included) on a non-volatile matter (NV) basis is preferably more than 50% by weight, more preferably Preferably it is 65 weight% or more, More preferably, it is 75 weight% or more. As such a natural wax, for example, carnauba wax (generally, melicil serotate is included in a proportion of 60% by weight or more, more preferably 70% by weight or more, still more preferably 80% by weight or more. ), vegetable waxes such as palm wax; animal waxes such as beeswax and spermaceti; and the like. The melting point of such natural wax is preferably 50°C or higher, more preferably 60°C or higher, still more preferably 70°C or higher, and particularly preferably 75°C or higher. As the raw material for the topcoat layer, a chemically synthesized wax ester may be used, or a wax ester obtained by refining a natural wax to increase the purity of the wax ester may be used. The number of these raw materials may be one, and 2 or more types may be sufficient as them.

The proportion of the lubricant in the entire topcoat layer is preferably 5% by weight to 50% by weight, and more preferably 10% by weight to 40% by weight. When there is too little content rate of a lubricant, there exists a possibility that scratch resistance may fall easily. When there is too much content rate of a lubricant, there exists a possibility that the improvement effect of whitening resistance may become insufficient easily.

The top coat layer may contain another lubricant in addition to the wax ester. Other lubricants include, for example, petroleum waxes (paraffin wax, etc.), mineral waxes (montan wax, etc.), higher fatty acids (cerotic acid, etc.), neutral fats (palmitic acid triglyceride, etc.) other than wax esters. waxes. Moreover, in addition to the wax ester, you may contain a silicone type lubricant, a fluorine type lubricant, etc. A preferred embodiment of the top coat layer is a form substantially free of silicone lubricants and fluorine-based lubricants, for example, the total content of the silicone lubricant and fluorine-based lubricant is the total amount of the top coat layer, preferably 0.01% by weight or less, More preferably, it is below the detection limit.

The top coat layer is, if necessary, an antistatic component, a crosslinking agent, an antioxidant, a colorant (pigment, dye, etc.), a fluidity regulator (thixotropic agent, a thickener, etc.), a film forming aid, a surfactant (antifoaming agent, a dispersing agent, etc.), a preservative It may contain additives such as

<Antistatic component of top coat layer>

A preferred embodiment of the top coat layer contains an antistatic component. As an antistatic component, it is a component which can exhibit the effect|action which prevents or suppresses charging of a protective film. When the topcoat layer contains an antistatic component, as the antistatic component, for example, an organic or inorganic conductive substance, various antistatic agents, and the like can be used. It is also possible to use an antistatic agent that can be used in the antistatic layer described above.

Examples of the organic conductive substance include cationic antistatic agents having a cationic functional group such as a quaternary ammonium salt, a pyridinium salt, a first amino group, a second amino group, and a tertiary amino group; anionic antistatic agents having anionic functional groups such as sulfonic acid salts, sulfate salts, phosphonate salts and phosphoric acid ester salts; zwitterionic antistatic agents such as alkylbetaine and derivatives thereof, imidazoline and derivatives thereof, alanine and derivatives thereof; Nonionic antistatic agents, such as amino alcohol and its derivative(s), glycerol and its derivative(s), polyethyleneglycol, and its derivative(s); an ion conductive polymer obtained by polymerizing or copolymerizing a monomer having an ion conductive group (eg, a quaternary ammonium base) of the cation type, anionic type, or amphoteric ion type; conductive polymers such as polythiophene, polyaniline, polypyrrole, polyethyleneimine, and allylamine polymers; and the like. The number of such antistatic agents may be one, and 2 or more types may be sufficient as them.

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), etc. are mentioned. One type may be sufficient as such an inorganic conductive substance, and 2 or more types may be sufficient as it.

Examples of the antistatic agent include a cationic antistatic agent, an anionic antistatic agent, a zwitterionic antistatic agent, a nonionic antistatic agent, obtained by polymerizing or copolymerizing a monomer having an ion conductive group of the above cationic, anionic, and amphoteric ionic groups. An ion conductive polymer etc. are mentioned.

When the top coat layer contains an antistatic component, preferably the antistatic component contains an organic conductive material. As the organic conductive material, various conductive polymers can be preferably used. According to such a structure, favorable antistatic property and high scratch resistance can be made compatible.

Examples of the conductive polymer include polythiophene, polyaniline, polypyrrole, polyethyleneimine, and allylamine polymers. One type may be sufficient as such a conductive polymer, and 2 or more types may be sufficient as it. Moreover, you may use in combination with other antistatic components (inorganic electroconductive substance, antistatic agent, etc.).

The amount of the conductive polymer used is preferably 1 part by weight to 100 parts by weight, more preferably 2 parts by weight to 70 parts by weight, still more preferably 3 parts by weight with respect to 100 parts by weight of the binder contained in the topcoat layer. parts to 50 parts by weight. When there is too little usage-amount of a conductive polymer, there exists a possibility that the antistatic effect may become small. When the amount of the conductive polymer used is too large, the compatibility of the conductive polymer in the topcoat layer tends to be insufficient, and there is a risk that the appearance quality of the topcoat layer may decrease or solvent resistance may decrease.

The conductive polymer preferably includes polythiophene and polyaniline. As polythiophene, the weight average molecular weight (Mw) in terms of polystyrene becomes like this. Preferably it is 40x10< ⁴ > or less, More preferably, it is 30x10< ⁴ > or less. As polyaniline, the weight average molecular weight (Mw) in terms of polystyrene becomes like this. Preferably it is 50x10< ⁴ > or less, More preferably, it is 30x10< ⁴ > or less. The polystyrene conversion weight average molecular weight (Mw) of the conductive polymer is preferably 0.1×10 ⁴ or more, and more preferably 0.5×10 ⁴ or more. In the present specification, polythiophene refers to a polymer of unsubstituted or substituted thiophene. Examples of the substituted thiophene polymer include poly(3,4-ethylenedioxythiophene) and the like.

As a method of forming the top coat layer, when a method of applying a coating material for forming the top coat layer to a base material and drying or curing is adopted, as a conductive polymer used for preparing the coating material, the conductive polymer is dissolved or dispersed in water. It can be preferably used in the form of a conductive polymer (a conductive polymer aqueous solution). Such an aqueous conductive polymer solution can be prepared, for example, by dissolving or dispersing in water a conductive polymer having a hydrophilic functional group (a conductive polymer that can be synthesized by a method such as copolymerizing a monomer having a hydrophilic functional group in a molecule) in water. Examples of the hydrophilic functional group include a sulfo group, an amino group, an amide group, an imino group, a hydroxyl group, a mercapto group, a hydrazino group, a carboxyl group, a quaternary ammonium group, a sulfuric acid ester group (-O-SO ₃ H), a phosphate ester group (eg For example, -O-PO(OH) ₂ ) etc. are mentioned. Such a hydrophilic functional group may form a salt. As a commercial item of polythiophene aqueous solution, the brand name "Denatron" series by the Nagase Chemtech company, etc. are mentioned, for example. As a commercial item of polyaniline sulfonic acid aqueous solution, the Mitsubishi Rayon company make brand name "aqua-PASS" etc. are mentioned, for example.

In preparation of a coating material, Preferably, polythiophene aqueous solution is used. As the polythiophene aqueous solution, a polythiophene aqueous solution containing polystyrene sulfonate (PSS) (for example, a form in which PSS is added to polythiophene as a dopant) is preferable. This aqueous polythiophene solution may contain polythiophene: PSS, preferably in a mass ratio of 1:1 to 1:10. The total content of polythiophene and PSS in this aqueous polythiophene solution is preferably 1% by mass to 5% by mass. As a commercial item of such polythiophene aqueous solution, the brand name of H.C. Stark company "Baytron" etc. are mentioned, for example. In addition, when using the polythiophene aqueous solution containing PSS as described above, the total amount of polythiophene and PSS is preferably 5 to 200 parts by weight, more preferably 5 to 200 parts by weight based on 100 parts by weight of the binder. It is 10 weight part - 100 weight part, More preferably, it is 25 weight part - 70 weight part.

The topcoat layer may contain a conductive polymer and one or more other antistatic components (organic conductive substances other than conductive polymers, inorganic conductive substances, antistatic agents, etc.) together as needed. Preferably, the topcoat layer contains substantially no antistatic component other than a conductive polymer. That is, it is preferable that the antistatic component contained in the top coat layer substantially contains only a conductive polymer.

<Crosslinking agent>

The top coat layer preferably contains a crosslinking agent. As a crosslinking agent, crosslinking agents, such as a melamine type crosslinking agent, an isocyanate type crosslinking agent, and an epoxy type crosslinking agent, used for crosslinking of general resin can be selected suitably and can be used. By using such a crosslinking agent, at least one of the effects of improvement of scratch resistance, improvement of solvent resistance, improvement of print adhesion, and decrease of friction coefficient (that is, improvement of slidability) can be realized. Preferably, the crosslinking agent comprises a melamine-based crosslinking agent. The crosslinking agent may be a topcoat layer in which the crosslinking agent substantially contains only a melamine-based crosslinking agent (melamine-based resin) (that is, substantially no crosslinking agent other than the melamine-based crosslinking agent).

<One preferred aspect of the top coat layer>

One preferred aspect of the top coat layer is that when the material of the base layer is at least one selected from polyimide and polyether ether ketone, the top coat layer contains a binder including a urethane-based resin and an antistatic component. . In this way, by employing a binder containing a urethane-based resin as the binder of the antistatic component of the top coat layer, the top coat layer on the surface of the base material layer made of at least one material selected from polyimide and polyether ether ketone. The coating formability becomes excellent, and an external appearance can be made good, and the outstanding antistatic property can be expressed.

As the binder of the antistatic component of the top coat layer, a binder containing a polyester resin is often preferable, but for a specific substrate layer in which the material of the substrate layer is at least one selected from polyimide and polyether ether ketone, The affinity of the binder containing a polyester resin may be low, and there exists a possibility that the external appearance after application|coating formation of a top coat layer may worsen, and there exists a possibility that the outstanding antistatic property may not be expressed. As described above, when the material of the base layer is at least one selected from polyimide and polyether ether ketone, when the top coat layer contains a binder including a urethane-based resin and an antistatic component, the surface of the base layer It becomes excellent in the coating formability of the top coat layer to a metal, and while a thing with a favorable external appearance can be obtained, the outstanding antistatic property can be expressed.

<Formation of top coat layer>

The top coat layer can be suitably formed by a method comprising applying to a substrate a liquid composition (coating material for forming a top coat layer) in which the resin component and optionally used additives are dispersed or dissolved in a suitable solvent. . For example, a method of applying the coating material to the first surface of the substrate, drying it, and performing a curing treatment (heat treatment, ultraviolet treatment, etc.) if necessary can be preferably employed. The NV (non-volatile content) of the coating material is preferably 5% by weight or less, more preferably 0.05% by weight to 5% by weight, still more preferably 0.05% by weight to 1% by weight, particularly preferably 0.10% by weight. % to 1% by weight. In the case of forming a topcoat layer having a small thickness, the NV of the coating material is preferably 0.05 wt% to 0.50 wt%, and more preferably 0.10 wt% to 0.30 wt%. By using such a low NV coating material, a more uniform top coat layer can be formed.

The solvent constituting the coating material for forming the top coat layer is preferably one capable of stably dissolving or dispersing the component for forming the top coat layer. Such a solvent may be an organic solvent, water, or a mixed solvent thereof. Examples of the organic solvent include esters such as ethyl acetate; 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; glycol ethers such as alkylene glycol monoalkyl ethers (eg, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether) and dialkylene glycol monoalkyl ether; At least 1 type selected from etc. is mentioned. Preferably, the solvent constituting the coating material for forming the top coat layer is water or a mixed solvent containing water as a main component (eg, a mixed solvent of water and ethanol).

<Properties of the top coat layer>

The thickness of the top coat layer is preferably 3 nm to 500 nm, more preferably 3 nm to 100 nm, and still more preferably 3 nm to 60 nm. When the thickness of the topcoat layer is too large, there exists a possibility that transparency (light transmittance) of a protective film may fall easily. If the thickness of the top coat layer is too small, it may be difficult to form the top coat layer uniformly. , there is a possibility that the appearance of the protective film may be easily stained.

The thickness of the topcoat layer can be grasped by observing the cross section of the topcoat layer with a transmission electron microscope (TEM). For example, a target sample (a base material having a top coat layer, a protective film provided with a base material, etc.) is subjected to a heavy metal dyeing treatment for the purpose of making the top coat layer clear, followed by resin embedding, and ultra-thin The result obtained by performing TEM observation of the sample cross section by the sectioning method can be suitably employ|adopted as the thickness of a topcoat layer. As TEM, TEM (model "H-7650") by Hitachi Corporation etc. can be used, for example. In the examples to be described later, after binarization is performed on a cross-sectional image obtained under the conditions of acceleration voltage: 100 kV and magnification: 60,000 times, the thickness of the top coat layer (field of view) is divided by the cross-sectional area of the top coat by the sample length within the field of view. The average thickness of the inside) is actually measured. In addition, when the top coat layer can be observed sufficiently clearly even without heavy metal dyeing, the heavy metal dyeing treatment may be omitted. Alternatively, a calibration curve is created for the correlation between the thickness grasped by TEM and the detection result by various thickness detection devices (e.g., surface roughness meter, interferometric thickness meter, infrared spectrometer, various X-ray diffractometers, etc.) The thickness of the topcoat layer may be obtained by performing calculations.

The surface resistance value measured on the surface of the top coat layer is preferably 10 ¹² Ω or less, more preferably 10 ⁴ Ω to 10 ¹² Ω, still more preferably 10 ⁴ Ω to 10 ¹¹ Ω, particularly preferably preferably 5×10 ⁴ Ω to 10 ¹⁰ Ω, most preferably 10 ⁴ Ω to 10 ⁹ Ω. The protective film exhibiting such a surface resistance value can be suitably used as a protective film used, for example, in a process or conveyance process of an article weak to static electricity, such as a liquid crystal cell or a semiconductor device. The value of the surface resistance value is computable from the value of the surface resistance measured in 23 degreeC and 50 %RH atmosphere using a commercially available insulation resistance measuring apparatus.

The coefficient of friction of the top coat layer is preferably 0.4 or less. When a top coat layer with such a low coefficient of friction is used, when a load (a load that causes scratches) is applied to the top coat layer, the load is lightly carried along the surface of the top coat layer, thereby reducing the frictional force caused by the load. can do. Thereby, cohesive failure of the topcoat layer (damage mode in which the topcoat layer is destroyed) or interfacial failure (damage mode in which the topcoat layer peels off from the back surface of the substrate) is less likely to occur. Accordingly, it is possible to further prevent the occurrence of scratches on the protective film. The lower limit of the friction coefficient is preferably 0.1 or more, more preferably 0.15 or more, in consideration of the balance with other characteristics (eg, appearance quality, printability, etc.). As the coefficient of friction, for example, a value obtained by rubbing the surface of the topcoat layer with a vertical load of 40 mN in a measurement environment of 23° C. and 50% RH can be adopted. What is necessary is just to set the usage-amount of a lubricant so that a desirable coefficient of friction may be implement|achieved. It is also effective, for example, to increase the crosslinking density of the topcoat layer by adding a crosslinking agent or adjusting the film forming conditions for adjusting the friction coefficient.

It is preferable that the surface of the top coat layer has the property of being able to print easily with an oil-based ink (for example, using an oil-based marking pen). The protective film having such a top coat layer protects the identification number of the adherend to be protected, etc. in the process of processing or conveying the adherend (for example, optical component) performed in the state in which the protective film is affixed. It is suitable for describing and displaying on a film. Therefore, a topcoat layer excellent in printability in addition to appearance quality is preferable. For example, a topcoat layer having high printability with respect to an oil-based ink of a type in which the solvent is alcohol-based and contains a pigment is preferable. Also, a top coat layer in which the printed ink does not easily come off due to friction or transfer adhesion (that is, excellent in printing adhesion) is preferable. The top coat layer preferably has solvent resistance to such an extent that, when printing is corrected or erased, no noticeable change in appearance occurs even if the printing is wiped off with alcohol (eg, ethyl alcohol).

Since the top coat layer preferably contains a wax ester as a lubricant, a new peeling treatment (for example, any suitable release treatment agent such as a silicone-based release agent or a long-chain alkyl-based release agent is applied to the surface of the top coat layer and dried. Even in an embodiment in which no treatment) is performed, sufficient sliding properties (for example, the above-mentioned desirable coefficient of friction) can be realized. This embodiment in which the surface of the top coat layer is not subjected to a new peeling treatment is preferable in terms of being able to prevent in advance whitening due to the release treatment agent (for example, whitening due to storage under heating and humidification conditions). do. Moreover, it is advantageous also from the point of solvent resistance.

≪Other floors≫

The protective film according to an embodiment of the present invention may be implemented in an embodiment including another layer in addition to the base material, the pressure-sensitive adhesive layer, and the top coat layer. Examples of the arrangement of such "another layer" include between the first surface (back surface) of the substrate and the topcoat layer, and between the second surface (front surface) of the substrate and the pressure-sensitive adhesive layer. The layer disposed between the back surface of the substrate and the top coat layer may be, for example, a layer containing an antistatic component (antistatic layer). The layer disposed between the front surface of the substrate and the pressure-sensitive adhesive layer may be, for example, an undercoat layer (anchor layer), an antistatic layer, or the like, which enhances anchoring properties of the pressure-sensitive adhesive layer to the second surface. A protective film having a configuration in which an antistatic layer is disposed on the front surface of the substrate, an anchor layer is disposed on the antistatic layer, and an adhesive layer is disposed thereon may be used.

≪≪Foldable devices and rollable devices≫≫

Since the protective film according to the embodiment of the present invention is excellent in flexibility and transparency, for example, a bendable device (a device that can be bent), a foldable device (a device that can be folded), or a rollable device ( A device capable of being rounded) may be suitably provided. Since the protective film according to the embodiment of the present invention is particularly excellent in flexibility and transparency, it is suitable for foldable devices (devices capable of folding) and rollable devices (devices capable of rounding), which have been more difficult to apply so far. can

A foldable device according to an embodiment of the present invention includes a protective film according to an embodiment of the present invention. The foldable device of the present invention may include any appropriate other members as long as the protective film according to the embodiment of the present invention is provided.

A rollable device according to an embodiment of the present invention includes the protective film according to an embodiment of the present invention. The rollable device of the present invention may include any appropriate other members as long as the protective film according to the embodiment of the present invention is provided.

1 is a schematic cross-sectional view showing one embodiment of a foldable device according to an embodiment of the present invention as a representative example of one use mode of the protective film of the present invention. 1 , a foldable device 1000 according to an embodiment of the present invention includes a cover film 10 , an adhesive layer 20 , a polarizing plate 30 , an adhesive layer 40 , a touch sensor 50 , and an adhesive layer. (60), OLED 70, and the protective film 100 by embodiment of this invention are provided. In FIG. 1, the outermost layer by the side of the protective film 100 by embodiment of this invention of OLED 70 is a polyimide board|substrate typically. Moreover, on the opposite side of the protective film 100 by embodiment of this invention of a polyimide board|substrate, Preferably, the barrier layer is provided. The protective film 100 by embodiment of this invention is comprised from the adhesive layer 80 and the base material layer 90 in FIG. The pressure-sensitive adhesive layer 20, the pressure-sensitive adhesive layer 40, and the pressure-sensitive adhesive layer 60 may be a pressure-sensitive adhesive layer containing an adhesive having the same composition as the pressure-sensitive adhesive layer 80 constituting the protective film 100 of the present invention, or may have a different composition. An adhesive layer containing an adhesive may be sufficient.

Since the protective film according to the embodiment of the present invention is excellent in flexibility and transparency, for example, a bendable device (a device that can be bent), a foldable device (a device that can be folded), or a rollable device ( It may be suitably provided on the back surface (the display surface is the opposite surface) of a device capable of being rounded. 1 is a view provided on the rear surface (the display surface is opposite to) of a foldable device (foldable device).

[Example]

Hereinafter, an Example and a comparative example are given and this invention is demonstrated more concretely. However, this invention is not limited to them at all. In addition, in the following description, "part" and "%" are based on weight unless there is a particular specification.

<Observation of particles or aggregates of particles in the base layer>

The inside of the base layer was observed using a digital microscope (manufactured by OLYMPUS, BX51, objective lens: 20×/0.40 BD P), and the ferret diameter of particles or aggregates of particles in the base layer was measured. In addition, the case where the number of particles observed per unit area (0.02 mm ² ) of particles or aggregates of particles having a ferret diameter of 1 μm or more was 10 or more was “many”, and the case where it was 9 or less was “substantially not included”.

<Evaluation of yield>

A foreign material inspection of an area of 10 cm ² by the naked eye of the protective film and a foreign material inspection of an area of 0.1 mm ² by a microscope (manufactured by Shodensha, USH140CCD-L1) were performed. In the inspection of foreign substances by visual inspection, one or more foreign substances of 50 µm or more are detected as "failed". was calculated|required with image processing software (imageJ), and the calculated|required area made 0.1 % or more thing "disqualified".

In both the visual inspection and the inspection by a microscope image, the final “accepted product” is not “failed”. Those above were designated as ○. In addition, since the thing whose transmittance|permeability of a protective film was 40 % or less, or a haze of 10 % or more could not perform a visual inspection correctly, it was set as (triangle|delta) irrespective of said (circle) or x.

<Surface roughness (Ra)>

Regarding the surface of the outermost layer of the protective film on the opposite side to the pressure-sensitive adhesive layer when viewed from the base layer, NewView7300 (manufactured by ZYGO), zoom lens (internal lens) 1.00x, objective lens 2.5x/0.075 TI OFN22 WD 10.3 (Nikon) company), the surface roughness was measured, and Ra was calculated using analysis software (Metro Pro).

<Bending Test>

As shown in Fig. 2, the protective film in a flat state was fixed in a state of being sandwiched between the silicone-treated surfaces of the silicone-treated separator in a state where the protective film was bent at 6 Φ with the pressure-sensitive adhesive layer side facing outward, and was then fixed at 90 ° C. time was maintained. After that, the bending was released and left to stand at 23°C and 50%RH for 24 hours, the angle of the bent film was measured. The case where it was completely restored to the original state was 180 degrees, and the case where the bent state in the initial fixation was maintained as it was was made into 0 degrees.

<Measurement of haze and total light transmittance>

Haze (%) = (Td/Tt) x 100 (Td: diffuse transmittance, Tt according to JIS-K-7136 using a haze meter HM-150 (manufactured by Murakami Shikisai Kijutsu Genkyujo Co., Ltd.) : Total light transmittance). In addition, the total light transmittance was measured based on JIS-K-7316.

<Young's Yul>

S-S (Strain-Strength) obtained by cutting a sample piece into a rectangle with a width of 10 mm ) The Young's modulus was obtained from the curve. As the measurement conditions, the tensile speed was 200 mm/min and the chuck interval was 50 mm. In the method of obtaining the Young's modulus from the S-S curve, a graph of the S-S curve was created, a tangent line (linear equation) was drawn on the graph in a displacement range of 1 mm to 2 mm, and it was obtained from the slope of the tangent line. The thickness was computed using the thickness of the base material layer.

<Adhesiveness>

The protective film was cut|disconnected by width 25mm and length 150mm, and it was set as the sample for evaluation. In an atmosphere of a temperature of 23° C. and a humidity of 50% RH, the surface of the pressure-sensitive adhesive layer of the evaluation sample was affixed to a glass plate (manufactured by Matsunami Glass Kogyo Co., Ltd., trade name: Microslide Glass S) by one reciprocation of a 2.0 kg roller. . After curing for 30 minutes in an atmosphere of a temperature of 23° C. and a humidity of 50% RH, it is peeled off at a peeling angle of 180 degrees and a tensile rate of 300 mm/min using a universal tensile tester (manufactured by Minebea Co., Ltd., product name: TCM-1kNB). to measure the adhesive force.

<Surface resistance value>

Using a resistivity meter (manufactured by Mitsubishi Chemical Analytech, “Hirestar UP MCP-HT450 Type”), the URS probe is brought into contact with the adhesive layer non-laid surface of the protective film under the conditions of an applied voltage of 100 V and a voltage application time of 10 seconds. The surface resistance value was measured.

<Storage modulus (G') and glass transition temperature>

Only the adhesive layer was taken out from the protective film and laminated|stacked, and what was made into thickness about 1.5 mm was made into the sample for a measurement. Dynamic viscoelasticity was measured under the following conditions using "Advanced Rheometric Expansion System (ARES)" by Rheometric Scientific. From the measurement results, the storage modulus (G') and loss tangent (tanδ) at each temperature were read. In addition, the temperature at which tan δ becomes the maximum was made into the glass transition temperature (Tg) of an adhesive layer.

(Measuring conditions)

Deformation mode: torsion

Measuring frequency: 1Hz

Temperature increase rate: 5°C/min

Shape: Parallel plate 7.9mmφ

<Repeated bending test (evaluation of bending durability)>

The release liner was peeled off from the protective film, it was joined to a 75-micrometer-thick Upilex 75S (made by Ube Kosan Co., Ltd.), and it was crimped|bonded with a hand roller. This laminate was cut out to the size of 50 mm x 100 mm, the autoclave process was performed at 35 degreeC and 0.35 MPa for 15 minutes, and the test piece was obtained. Using a planar body no-load U-shaped expansion tester (manufactured by Yuasa System Kiki), a bending jig is installed on the short side of the test piece, and in a thermostat of 25°C and -20°C, the Upilex 75S side of the test piece is turned to the outside. Thus, a repeated bending test was performed under the following conditions.

(Exam conditions)

Bending Radius: 3mm

Bending angle: 180°

Bending speed: 1 second/time

Number of bends: 200,000 times

The test piece after the repeated bending test was visually confirmed and evaluated according to the following criteria.

(circle): There is no peeling of an adhesive layer and a base material layer, and mixing of the bubble into the adhesive interface is not seen.

×: There is peeling of the pressure-sensitive adhesive layer and the base layer, or bubbles are generated at the bonding interface

[Production Example 1]: Preparation of the pressure-sensitive adhesive composition A

2-ethylhexyl acrylate (2EHA) as a monomer component: 63 parts by weight, N-vinyl-2-pyrrolidone (NVP): 15 parts by weight, methyl methacrylate (MMA): 9 parts by weight, 2-hydroxy acrylic acid Ethyl (HEA): 13 parts by weight, 2,2'-azobisisobutyronitrile as a polymerization initiator: 0.2 parts by weight, and ethyl acetate as polymerization solvent: 133 parts by weight were put into a separable flask, and nitrogen gas was introduced while introducing Stirred for 1 hour. After removing oxygen in the polymerization system in this way, the temperature was raised to 65° C. and reacted for 10 hours, and then ethyl acetate was added to obtain a solution of the acrylic polymer (a) having a solid content concentration of 30% by weight.

Next, to the solution of the acrylic polymer (a), an isocyanate-based crosslinking agent (trade name "Takenate D110N", manufactured by Mitsui Chemicals Co., Ltd.) is added to the solution of the acrylic polymer (a) (solid content) by 1 weight part in terms of solid content with respect to 100 parts by weight of the acrylic polymer (a) (solid content) It added so that it might become possible, and the adhesive composition A was prepared.

The composition is summarized in Table 1.

[Production Example 2]: Preparation of the pressure-sensitive adhesive composition B

(Preparation of oligomer (1))

Dicyclofentanyl methacrylate (DCPMA) as a monomer component: 60 parts by weight and methyl methacrylate (MMA): 40 parts by weight, α-thioglycerol as a chain transfer agent: 3.5 parts by weight and toluene as a polymerization solvent: 100 parts by weight by mixing , and stirred for 1 hour at 70°C under a nitrogen atmosphere. Next, 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) as a thermal polymerization initiator was added and reacted at 70°C for 2 hours, then heated to 80°C and reacted for 2 hours. Then, the reaction liquid was heated to 130 degreeC, toluene, a chain transfer agent, and an unreacted monomer were dried off, and the solid acrylic oligomer (oligomer (1)) was obtained. The weight average molecular weight of the oligomer (1) was 5100, and the glass transition temperature (Tg) was 130 degreeC.

(Preparation of prepolymer composition)

As a monomer component for forming the prepolymer, lauryl acrylate (LA): 35 parts by weight, 2-ethylhexyl acrylate (2EHA): 49 parts by weight, 4-hydroxybutyl acrylate (4HBA): 7 parts by weight and N- Vinyl-2-pyrrolidone (NVP): 9 parts by weight, and "Irgacure 184" manufactured by BASF as a photopolymerization initiator: 0.015 parts by weight were blended, and polymerization was performed by irradiating ultraviolet rays, and prepolymer composition B (polymerization rate: about 10%) was obtained.

(Preparation of adhesive composition)

Prepolymer composition B: 100 parts by weight, as a post-addition component, 1,6-hexanediol diacrylate (HDDA): 0.07 parts by weight, oligomer (1): 3 parts by weight, and a silane coupling agent (manufactured by Shin-Etsu Chemical " KBM403"): After adding 0.3 weight part, these were mixed uniformly, and the adhesive composition B was prepared.

The composition is summarized in Table 1.

[Production Example 3]: Preparation of the pressure-sensitive adhesive composition C

(Preparation of prepolymer composition)

As a monomer component for forming a prepolymer, lauryl acrylate (LA): 60 parts by weight, 2-ethylhexyl acrylate (2EHA): 22 parts by weight, 4-hydroxybutyl acrylate (4HBA): 8 parts by weight and N- Vinyl-2-pyrrolidone (NVP): 10 parts by weight, and "Irgacure 184" manufactured by BASF as a photopolymerization initiator: 0.015 parts by weight were blended, and polymerization was performed by irradiating ultraviolet rays, and prepolymer composition C (polymerization rate: about 10%) was obtained.

(Preparation of adhesive composition)

Prepolymer composition C: 100 parts by weight, as a post-addition component, 1,6-hexanediol diacrylate (HDDA): 0.06 parts by weight, oligomer (1) prepared in Preparation Example 2: 3 parts by weight and a silane coupling agent (sine S-Chemical "KBM403"): After adding 0.3 weight part, these were mixed uniformly, and the adhesive composition C was prepared.

The composition is summarized in Table 1.

[Production Example 4]: Preparation of pressure-sensitive adhesive composition D

(Preparation of acrylic polymer D)

In a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler, lauryl acrylate (LA): 19.4 parts by weight, 2-ethylhexyl acrylate (2EHA): 67.9 parts by weight, n-butyl acrylate (BA): 7.8 parts by weight, 4-hydroxybutylacrylate (4HBA): 3.9 parts by weight, and N-vinyl-2-pyrrolidone (NVP): 1.0 part by weight, and 2,2'-azo as a polymerization initiator Bisisobutyronitrile (AIBN): 0.1 parts by weight is added, ethyl acetate is added so that the total concentration thereof is 42% by weight, and the inside of the system is purged with nitrogen over 1 hour while slowly stirring, and the temperature of the liquid in the flask is around 58°C The polymerization reaction was carried out for 5 hours, and after completion of the reaction, ethyl acetate was added to adjust the polymer concentration to 32% by weight to obtain an acrylic polymer D solution. The weight average molecular weight of the acrylic polymer D was 1.57 million.

(Preparation of adhesive composition D)

Acrylic polymer D: 100 parts by weight, Coronate HX (manufactured by Tosoh Corporation, isocyanate-based crosslinking agent) as a crosslinking agent: 0.05 parts by weight, the oligomer (1) prepared in Production Example 2: 2 parts by weight, Irganox 1010 as an antioxidant (manufactured by BASF): 0.3 parts by weight of Nassem Ferric as a catalyst (manufactured by Nippon Chemical Industry Co., Ltd.): 0.01 parts by weight were mixed and thoroughly stirred so that the total solid content was 21% by weight of ethyl acetate and solvent. By diluting with acetylacetone used in the quantity of 2 weight%, the adhesive composition D was prepared.

The composition is summarized in Table 1.

[Production Example 5]: Preparation of the pressure-sensitive adhesive composition E

(Preparation of acrylic polymer E)

Lauryl acrylate (LA): 8.0 parts by weight, 2-ethylhexyl acrylate (2EHA): 70.3 parts by weight, n-butyl acrylate in a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler (BA): 20.1 parts by weight, 4-hydroxybutylacrylate (4HBA): 1.0 part by weight, and N-vinyl-2-pyrrolidone (NVP): 0.6 parts by weight, and 2,2'-azo as a polymerization initiator Bisisobutyronitrile (AIBN): 0.1 part by weight is added, ethyl acetate is added so that the total concentration thereof becomes 47% by weight, and the inside of the system is purged with nitrogen over 1 hour while slowly stirring, and the temperature of the liquid in the flask is around 56°C Polymerization reaction was carried out for 6 hours by holding at The weight average molecular weight of the acrylic polymer E was 2.09 million.

(Preparation of adhesive composition E)

Acrylic polymer E: 100 parts by weight, Coronate HX (manufactured by Tosoh Corporation, isocyanate-based crosslinking agent) as a crosslinking agent: 0.03 parts by weight, the oligomer (1) prepared in Production Example 2: 5 parts by weight, Irganox 1010 as an antioxidant (manufactured by BASF): 0.3 parts by weight of Nassem Ferric as a catalyst (manufactured by Nippon Chemical Industry Co., Ltd.): 0.01 parts by weight were mixed and thoroughly stirred so that the total solid content was 21% by weight of ethyl acetate and solvent. By diluting with acetylacetone used as 2 weight%, the adhesive composition E was prepared.

The composition is summarized in Table 1.

[Production Example 6]: Preparation of the pressure-sensitive adhesive composition F

(Preparation of adhesive composition F)

Acrylic polymer E prepared in Preparation Example 5: 100 parts by weight, peroxide as a crosslinking agent (Niper BMT-40SV, manufactured by Nippon Yushi Co., Ltd.): 0.25 parts by weight, oligomer (1) prepared in Preparation Example 2: 3 parts by weight, antioxidant Irganox 1010 (manufactured by BASF): 0.3 parts by weight as a catalyst, ferric Nasem (manufactured by Nippon Chemical Industries, Ltd.): 0.01 parts by weight as a catalyst, mixed and thoroughly stirred, acetic acid so that the total solid content is 21 wt% The pressure-sensitive adhesive composition F was prepared by diluting with ethyl and acetylacetone in the amount of 2% by weight of the solvent content.

The composition is summarized in Table 1.

[Production Example 7]: Preparation of the pressure-sensitive adhesive composition G

(Preparation of prepolymer composition)

As a monomer component for forming a prepolymer, lauryl acrylate (LA): 99 parts by weight and 4-hydroxybutyl acrylate (4HBA): 1 part by weight, and "Irgacure 184" manufactured by BASF as a photoinitiator: 0.015 parts by weight It was blended and superposed|polymerized by irradiating an ultraviolet-ray, and the prepolymer composition G (polymerization rate: about 10%) was obtained.

(Preparation of adhesive composition)

Prepolymer composition G: 100 parts by weight, as a post-addition component, 1,6-hexanediol diacrylate (HDDA): 0.30 parts by weight and silane coupling agent (“KBM403” manufactured by Shin-Etsu Chemical): 0.3 parts by weight were added Then, these were mixed uniformly, and the adhesive composition G was prepared.

The composition is summarized in Table 1.

[Example 1]

A commercially available release liner (diafoil MRF-38, manufactured by Mitsubishi Juicy Co., Ltd.) was prepared. The adhesive composition A was apply|coated so that the thickness after drying might be set to 25 micrometers on one side (release surface) of a release liner, and it dried at 130 degreeC for 3 minutes. In this way, the 25-micrometer-thick adhesive layer comprised by the acrylic adhesive A corresponding to the adhesive composition A was formed on the peeling surface of the peeling liner.

As the base layer, a polyimide-based base material having a thickness of 25 µm (trade name "Upilex-25S", manufactured by Ube Kosan Co., Ltd.) was prepared. The pressure-sensitive adhesive layer formed on the release liner was bonded to one side of the base layer. The release liner was left on the pressure-sensitive adhesive layer as it was, and was used for protecting the surface (adhesive layer surface) of the pressure-sensitive adhesive layer. The obtained structure was passed through a laminator (0.3 MPa, speed 0.5 m/min) at 80°C once, and then aged in an oven at 50°C for 1 day. In this way, the protective film (1) was obtained.

The results are shown in Table 2.

[Example 2]

A protective film (2) was obtained in the same manner as in Example 1, except that a 50 µm-thick polyimide-based substrate (trade name "Upilex-50RN", manufactured by Ube Kosan Co., Ltd.) was used as the substrate layer.

The results are shown in Table 2.

[Example 3]

A protective film (3) was obtained in the same manner as in Example 1 except that a 25 µm-thick polyether ether ketone (PEEK) base material (trade name "Xpeak", manufactured by Kurabo) was used as the base layer.

The results are shown in Table 2.

[Example 4]

A protective film (4) was obtained in the same manner as in Example 1 except that a 50 µm-thick polyimide-based substrate (trade name: “Neo-Ansul S100”, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was used as the substrate layer.

The results are shown in Table 2.

[Example 5]

A protective film (5) was obtained in the same manner as in Example 1 except that a 50 µm-thick polyimide-based substrate (trade name "Upilex-50S", manufactured by Ube Kosan Corporation) was used as the substrate layer.

The results are shown in Table 2.

[Example 6]

As a base material layer, it carried out similarly to Example 1 except having used the 50-micrometer-thick PEN base material (trade name "PEN Q51", the Teijin Corporation make), and the protective film (6) was obtained.

The results are shown in Table 2.

[Example 7]

A 75 μm thick polyethylene terephthalate (PET) film (“Diafoil MRF75” manufactured by Mitsubishi Chemical) having a silicone-based release layer provided on its surface is used as a substrate (cumulative release film), and the pressure-sensitive adhesive composition B is applied on the substrate to a thickness of 25 μm. The coating layer was formed by coating. On this application layer, a PET film (“Diafoil MRE75” manufactured by Mitsubishi Chemical) having a thickness of 75 µm on one side of which a silicone peeling process was performed was bonded as a cover sheet (cumulatively peelable film). This laminate was photocured by irradiating ultraviolet rays with a black light positioned so that the irradiation intensity on the irradiated surface directly under the lamp from the cover sheet side was 5 mW/cm ² , and then photo-curing the adhesive sheet with a thickness of 25 µm. got

As the base layer, a polyimide-based base material having a thickness of 50 µm (trade name "Upilex-50S", manufactured by Ube Kosan Co., Ltd.) was prepared. The light-peelable film of the said adhesive sheet was peeled to one side of this base material layer, and the adhesive layer was bonded together. The said heavy peeling film was left on an adhesive layer as it was, and was used for protection of the surface (adhesive layer surface) of this adhesive layer. The obtained structure was passed through a laminator (0.3 MPa, speed 0.5 m/min) at 80°C once, and then aged in an oven at 50°C for 1 day. In this way, a protective film (7) was obtained.

The results are shown in Table 2.

[Example 8]

Except having used the adhesive composition C instead of the adhesive composition B, it carried out similarly to Example 7, and obtained the protective film (8).

The results are shown in Table 2.

[Example 9]

Except having used the adhesive composition D instead of the adhesive composition A, it carried out similarly to Example 5, and obtained the protective film (9).

The results are shown in Table 2.

[Example 10]

It carried out similarly to Example 5 except having used the adhesive composition E instead of the adhesive composition A, and the protective film 10 was obtained.

The results are shown in Table 2.

[Example 11]

A commercially available release liner ("Diafoil MRF-38", manufactured by Mitsubishi Jushi Co., Ltd.) was prepared. The adhesive composition F was apply|coated so that the thickness after drying might be set to 25 micrometers to one side (release side) of a release liner, and it dried at 155 degreeC for 3 minutes. In this way, the 25-micrometer-thick adhesive layer comprised by the acrylic adhesive F corresponding to the adhesive composition F was formed on the peeling surface of the peeling liner.

As the base layer, a polyimide-based base material having a thickness of 50 µm (trade name "Upilex-50S", manufactured by Ube Kosan Co., Ltd.) was prepared. The pressure-sensitive adhesive layer formed on the release liner was bonded to one side of the base layer. The release liner was left on the pressure-sensitive adhesive layer as it was, and was used for protecting the surface (adhesive layer surface) of the pressure-sensitive adhesive layer. The obtained structure was passed through a laminator (0.3 MPa, speed 0.5 m/min) at 80°C once, and then aged in an oven at 50°C for 1 day. In this way, the protective film 11 was obtained.

The results are shown in Table 2.

[Example 12]

It carried out similarly to Example 7 except having used the adhesive composition G instead of the adhesive composition B, and the protective film 12 was obtained.

The results are shown in Table 2.

[Comparative Example 1]

As a base material layer, it carried out similarly to Example 1, and obtained the protective film (C1) except having used the 25-micrometer-thick polyester base material (trade name "Lumiror S10", manufactured by Toray).

The results are shown in Table 2.

[Comparative Example 2]

As a base material layer, it carried out similarly to Example 1, and obtained the protective film (C2) except having used the 50-micrometer-thick polyester base material (trade name "Lumirer S10", manufactured by Toray).

The results are shown in Table 2.

[Comparative Example 3]

As the base layer, a protective film (C3) was obtained in the same manner as in Example 1 except that a polyimide-based base material having a thickness of 50 µm (trade name "Kapton 200H", manufactured by Toray DuPont Co., Ltd.) was used.

The results are shown in Table 2.

[Comparative Example 4]

As a base material layer, it carried out similarly to Example 1, and obtained the protective film (C4) except having used the 50-micrometer-thick polyimide-type base material (trade name "Pixio BP", manufactured by Kaneka Corporation).

The results are shown in Table 2.

The protective film of the present invention has excellent bending recovery properties, does not destroy the barrier layer even when bonded to the back side of a polyimide substrate provided with a barrier layer, is excellent in transparency, and is excellent in foreign material inspection properties, so For example, it can be suitably provided in a bendable device (a device that can be bent), a foldable device (a device that can be folded), or a rollable device (a device that can be rounded) having a movable bending portion.

1000: foldable device
100: protective film
10: cover film
20: adhesive layer
30: polarizer
40: adhesive layer
50: touch sensor
60: adhesive layer
70: OLED
80: adhesive layer
90: base layer
1: 6Φ glass rod
2: Silicon-treated separator
3: adhesive layer
4: fixed glass

Claims (27)

It is a protective film that is directly bonded to a polyimide substrate,
It has a base layer and an adhesive layer,
Observing the inside of the base layer using a digital microscope, measuring the ferret diameter of particles or agglomerates of particles in the base layer, and measuring the number of particles or aggregates of particles with a ferret diameter of 1 μm or more per unit area (0.02 mm ² ) is 9 or less,
protective film. The protective film of Claim 1 which has a top coat layer on the surface opposite to the surface which has the said adhesive layer of the said base material layer. The protective film according to claim 2, wherein the top coat layer contains a binder containing at least one selected from a polyester resin and a urethane resin. The protective film according to claim 3, wherein the binder includes a urethane-based resin. The protective film according to any one of claims 2 to 4, wherein the top coat layer contains an antistatic component. The protective film according to any one of claims 1 to 4, wherein the base layer has a Young's modulus at 23°C of 6.0×10 ⁷ Pa or more. The protective film according to any one of claims 1 to 4, wherein the material of the base layer is at least one selected from polyimide and polyether ether ketone. 5. The method according to any one of claims 1 to 4, wherein the base layer has a top coat layer on the opposite side to the side having the pressure-sensitive adhesive layer, and the top coat layer comprises a binder containing a urethane-based resin and an antistatic component. It contains, and the material of the said base material layer is at least 1 sort(s) chosen from polyimide and polyether ether ketone, The protective film. The bending angle according to any one of claims 1 to 4, wherein the bending angle after bending at 6 phi and holding at 90°C for 48 hours is 60 degrees after releasing the bending and leaving it to stand at 23°C and 50%RH for 24 hours to 180 degrees, a protective film. The protective film in any one of Claims 1-4 whose total light transmittance is 40 % or more. The protective film in any one of Claims 1-4 whose haze is 10 % or less. The protective film of any one of Claims 1-4 whose adhesive force with respect to the glass plate in 300 mm/min of tensile rates in 23 degreeC of the said adhesive layer, and a 180 degree peel is 1 N/25 mm or more. The protective film in any one of Claims 1-4 whose storage elastic modulus in 25 degreeC of the said adhesive layer is 75 kPa or less. The protective film in any one of Claims 1-4 whose Tg of the said adhesive layer is -10 degrees C or less. The protective film according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive layer contains an acrylic pressure-sensitive adhesive, and the acrylic pressure-sensitive adhesive contains an acrylic polymer as a base polymer. The acrylic polymer according to claim 15, wherein the acrylic polymer is obtained by polymerization of a monomer component (M), and among the monomer components (M), an alkyl (meth)acrylate represented by formula (1), R ¹ is a hydrogen atom Or the content rate of the alkyl (meth)acrylate (m1) which is a methyl group and R< ² > is a C10-20 chain|strand alkyl group is 5 weight% - 65 weight%, The protective film.
CH ₂ =C(R ¹ )COOR ² (1) The protective film of Claim 16 whose content rate of 2-ethylhexyl acrylate is 15 weight% - 85 weight% in the said monomer component (M). The protective film according to claim 17, wherein the total content of the alkyl (meth)acrylate (m1) and the 2-ethylhexyl acrylate in the monomer component (M) is 65% by weight to 98% by weight. The protective film according to claim 16, wherein R ² in the alkyl (meth)acrylate (m1) is a C10-13 chain alkyl group. The protective film according to claim 19, wherein the alkyl (meth)acrylate (m1) is lauryl acrylate. The protective film according to claim 16, wherein the monomer component (M) contains at least one selected from the group consisting of a hydroxyl group-containing monomer, a carboxyl group-containing monomer, and a nitrogen-containing monomer. The protective film according to any one of claims 1 to 4, which is affixed to the foldable member. The protective film according to claim 22, wherein the foldable member is an OLED. The protective film according to any one of claims 1 to 4, which is affixed to the rollable member. The protective film according to claim 24, wherein the rollable member is an OLED. A foldable device comprising the protective film according to any one of claims 1 to 4. A rollable device provided with the protective film in any one of Claims 1-4.

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