KR102579623B1 - Adhesive films, foldable devices and rollable devices - Google Patents

Abstract

An adhesive film with excellent flexibility and transparency is provided. Additionally, a foldable device and a rollable device with excellent flexibility are provided. The adhesive film of the present invention is an adhesive film having a base material layer and an adhesive layer, and tan δ (0.7%) at a strain of 0.7% measured in the tensile mode of a viscoelasticity measuring device is 0.1 or less. The adhesive film of the present invention is an adhesive film having a base layer and an adhesive layer, and tan δ (0.7%) at a strain of 0.7% and tan δ (0.1%) at a strain of 0.1% measured in the tensile mode of a viscoelasticity measuring device. The difference (tanδ(0.7%)-tanδ(0.1%)) is 0.05 or less.

Description

Adhesive films, foldable devices and rollable devices

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

Adhesive films are used to reinforce members of various shapes, protect their surfaces, etc.

For example, when bonding an integrated circuit (IC) or flexible printed circuit board (FPC) to a semiconductor device substrate (e.g., TFT substrate, etc.), heat compression is usually performed using an anisotropic conductive film (ACF). . When performing such thermocompression bonding, there are cases where an adhesive film is previously bonded to the back side of the substrate of the semiconductor element to reinforce it (for example, patent document 1).

In addition, as a manufacturing method for flexible devices and rollable devices that have been developed in recent years, a release layer and a flexible or rollable film substrate are generally formed on a support substrate such as glass, and a flexible or rollable film substrate is formed on the film substrate. An organic EL layer is formed on the TFT substrate. Then, the support substrate is peeled off to manufacture a flexible device or rollable device, but since the flexible display layer or rollable display layer is very thin, problems occur in the device due to handling, etc. For this reason, there are cases where an adhesive film is attached to this side for reinforcement (for example, patent document 2).

Substrates of semiconductor elements, flexible devices, and rollable devices may be repeatedly bent, and if the bending characteristics of the adhesive film bonded to the back side of the substrate are poor, recovery after bending will deteriorate, or, in the worst case, fracture due to repeated bending. There are times when you throw it away. Specifically, when an attempt is made to bond an adhesive film to a bent portion (for example, a movable bent portion of a folding member, etc.), the following problems arise, for example.

When the adhesive film is bent at an angle, a compressive force acts on the bent inner diameter side, so the adhesive film itself deforms to relieve the force. Specifically, for example, it becomes easy for wrinkles to form.

When the adhesive film is bent at an angle, a tensile stress acts on the bent outer diameter side. For this reason, when the stress is relieved, lifting from the adherend occurs.

When the adhesive film is bent at an angle, the thickness of the area where the adhesive film is bent or stretched changes significantly, and even in this state, wrinkles easily occur or lifting occurs. For example, when the adhesive film is stretched, the thickness of the adhesive film becomes significantly thinner, and lifting from the adherend becomes more likely to occur.

In this way, in conventional adhesive films, uneven tracking of corners and bends is not sufficiently achieved.

In particular, when the adhesive film is bonded to the movable bent portion, because the bending is repeated, fold marks (so-called “folds or creases”) are formed in the adhesive film on the movable bend portion.

Additionally, when bonding an integrated circuit (IC) or flexible printed circuit board (FPC) to a semiconductor device substrate (e.g., TFT substrate, etc.) by thermal compression, the bonding position is confirmed from the back side of the substrate before performing compression bonding. . For this reason, transparency is required for the adhesive film bonded to the back side of the substrate.

Japanese Patent No. 5600039 Publication Japanese Patent No. 6376271 Publication

The object of the present invention is to provide an adhesive film excellent in flexibility and transparency. Another object of the present invention is to provide a foldable device and a rollable device with excellent flexibility.

The adhesive film of the present invention,

It is an adhesive film having a base layer and an adhesive layer,

tanδ (0.7%) at 0.7% strain measured in the tensile mode of the viscoelasticity measuring device is 0.1 or less.

The adhesive film of the present invention,

It is an adhesive film having a base layer and an adhesive layer,

The difference (tanδ (0.7%) - tanδ (0.1%)) between tanδ (0.7%) at a strain of 0.7% and tanδ (0.1%) at a strain of 0.1% measured in the tensile mode of a viscoelasticity measuring device is 0.05 or less. am.

In one embodiment, the adhesive film of the present invention is bent to 6Φ and held at 90°C for 48 hours, then released from the bend and left at 23°C and 50% RH for 24 hours, and then the bending angle is 60 degrees. to 180 degrees.

In one embodiment, the adhesive film of the present invention has a top coating layer on the side of the base material layer opposite to the side having the adhesive layer.

In one embodiment, the top coating layer contains a binder containing at least one type selected from polyester resin and urethane resin.

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

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

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

In one embodiment, the material of the base layer is at least one selected from polyimide and polyetheretherketone.

In one embodiment, the adhesive film of the present invention has a top coating layer on the surface of the base layer opposite to the surface having the adhesive layer, and the top coating layer contains a binder containing a urethane resin and an antistatic component. And, the material of the base layer is at least one selected from polyimide and polyetheretherketone.

In one embodiment, the adhesive film of the present invention has a total light transmittance of 20% or more.

In one embodiment, the adhesive film of the present invention has a haze of 15% or less.

In one embodiment, the adhesive force of the adhesive layer to the SUS plate at 23°C, a tensile speed of 300 mm/min, and 180 degree peel is 1 N/25 mm or more.

In one embodiment, the adhesive layer contains an acrylic adhesive.

In one embodiment, the adhesive film of the present invention is attached to a foldable member.

In one embodiment, the foldable member is an OLED.

In one embodiment, the adhesive film of the present invention is attached to a rollable member.

In one embodiment, the rollable member is an OLED.

The foldable device of the present invention includes the adhesive film.

The rollable device of the present invention is provided with the adhesive film.

According to the present invention, an adhesive film excellent in flexibility and transparency can be provided. According to the present invention, it is also possible to provide a foldable device and a rollable device with excellent flexibility.

1 is a schematic cross-sectional view showing one embodiment of the foldable device of the present invention, and shows one use form of the adhesive film of the present invention.
Figure 2 is a schematic cross-sectional view illustrating the evaluation method for bending recovery.
Figure 3 is a schematic cross-sectional view illustrating the evaluation method for peeling evaluation.

≪≪Adhesive film≫≫

The adhesive film of the present invention has a base material layer and an adhesive layer. That is, as long as the adhesive film of the present invention has a base material layer and an adhesive layer, it may have any appropriate other layers as long as the effect of the present invention is not impaired.

The base material layer may be one layer or two or more layers. The base material layer is preferably one layer because the effect of the present invention can be more expressed.

The adhesive layer may be one layer or two or more layers. The pressure-sensitive adhesive layer is preferably one layer because it can more effectively express the effects of the present invention.

The adhesive film of the present invention may be provided with any suitable release liner on the surface of the adhesive layer opposite to the base material layer for protection until use.

Examples of the release liner include a release liner in which the surface of a base material (liner base material) such as paper or plastic film is treated with silicone, and a release liner in which the surface of a base material (liner base material) such as paper or plastic film is laminated with a polyolefin resin. etc. can be mentioned. Plastic films as liner substrates include, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, and polybutylene terephthalate. Phthalate film, polyurethane film, ethylene-vinyl acetate copolymer film, etc. can be mentioned.

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

The adhesive film of the present invention has a total thickness d of preferably 1 μm to 500 μm, more preferably 5 μm to 200 μm, further preferably 10 μm to 150 μm, and particularly preferably 20 μm. to 100㎛, most preferably 30㎛ to 80㎛. If the total thickness d of the adhesive film of the present invention is within the above range, the effects of the present invention can be more expressed.

The adhesive film of the present invention has tanδ (0.7%) at a strain of 0.7% measured in the tensile mode of a viscoelasticity measuring device of 0.1 or less, preferably 0.09 or less, more preferably 0.08 or less, and still more preferably is 0.07 or less, and is particularly preferably 0.06 or less. If tan δ (0.7%) of the adhesive film of the present invention at a strain of 0.7% measured in the tensile mode of a viscoelasticity measuring device is within the above range, the effect of the present invention can be more expressed.

Tan δ (0.7%) at 0.7% strain of the adhesive film measured in the tensile mode of the viscoelasticity measuring device is an index representing the loss tangent when the adhesive film is greatly bent. In completing the present invention, it was discovered based on various experimental data that if this value is within the above range, the effect of the present invention can be more expressed. The method of measuring tan δ (0.7%) at a strain of 0.7% measured in the tensile mode of the viscoelasticity measuring device will be described in detail later.

The adhesive film of the present invention has tanδ (0.1%) at a strain of 0.1% measured in the tensile mode of a viscoelasticity measuring device, preferably 0.1 or less, more preferably 0.08 or less, and even more preferably 0.06 or less. and is particularly preferably 0.05 or less. If the tan δ (0.1%) at 0.1% strain of the adhesive film of the present invention measured in the tensile mode of the viscoelasticity measuring device is within the above range, the effect of the present invention can be more expressed.

Tan δ (0.1%) at 0.1% strain of the adhesive film measured in the tensile mode of the viscoelasticity measuring device is an index representing the loss tangent when the adhesive film is slightly bent. In completing the present invention, it was discovered based on various experimental data that if this value is within the above range, the effect of the present invention can be more expressed. The method of measuring tanδ (0.1%) at a strain of 0.1% measured in the tensile mode of the viscoelasticity measuring device will be described in detail later.

The adhesive film of the present invention has a difference (tanδ (0.7%)-tanδ ( 0.1%)) is preferably 0.05 or less, more preferably 0.04 or less, and even more preferably 0.03 or less. The difference between tanδ (0.7%) at a strain of 0.7% and tanδ (0.1%) at a strain of 0.1% (tanδ (0.7%) - tanδ ( If 0.1%)) is within the above range, the effect of the present invention can be more expressed.

The difference between tanδ (0.7%) at a strain of 0.7% and tanδ (0.1%) at a strain of 0.1% (tanδ (0.7%) - tanδ (0.1%) of the adhesive film measured in the tensile mode of the viscoelasticity measuring device. ) is an index representing the difference between the loss tangent when the adhesive film is greatly bent and the loss tangent when the adhesive film is slightly bent. In completing the present invention, it was discovered based on various experimental data that if this value is within the above range, the effect of the present invention can be more expressed.

The adhesive film of the present invention is bent to 6Φ and held at 90°C for 48 hours, then released from the bend and left at 23°C and 50% RH for 24 hours, and then the bending angle is preferably 60 degrees to 180 degrees. , more preferably 80 degrees to 180 degrees, even 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 adhesive film of the present invention after being bent at 6Φ and held at 90°C for 48 hours, released from the bend, and left at 23°C and 50% RH for 24 hours is within the above range, then the bending angle of the adhesive film of the present invention is within the above range. The effect may be more pronounced.

The bending angle of the adhesive film after bending it to 6Φ and holding it at 90°C for 48 hours, releasing the bend, and leaving it to stand at 23°C and 50% RH for 24 hours is an indicator of recovery after bending. The method of measuring the bending angle after bending to 6Φ and holding at 90°C for 48 hours, releasing the bend, and leaving for 24 hours at 23°C and 50% RH will be explained in detail later.

The adhesive film of the present invention has a total light transmittance of preferably 20% or more, more preferably 30% or more, further preferably 40% or more, particularly preferably 50% or more, and most preferably is 60% or more. If the total light transmittance of the adhesive film of the present invention is within the above range, excellent transparency can be further exhibited.

The adhesive film of the present invention has a haze of preferably 15% or less, more preferably 13% or less, further preferably 10% or less, particularly preferably 8% or less, and most preferably 6% or less. % or less. If the haze of the adhesive film of the present invention is within the above range, excellent transparency can be further exhibited.

Since the adhesive film of the present invention is excellent in flexibility and transparency, it is preferably attached to a foldable member. As the foldable member, any suitable member can be employed as long as it is a member capable of repeated bending. Examples of such foldable members include foldable optical members and foldable electronic members, and a typical example is foldable OLED.

Since the adhesive film of the present invention is excellent in flexibility and transparency, it is preferably attached to a rollable member. As the rollable member, any appropriate member can be employed as long as it is a member capable of repeated winding and rewinding. Examples of such rollable members include rollable optical members and rollable electronic members, and a typical example is rollable OLED.

≪Base layer≫

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

The base material layer has a Young's modulus at 23°C of preferably 6.0 x 10 ⁷ Pa or more, more preferably 1.0 x 10 ⁸ Pa or more, even more preferably 5.0 x 10 ⁸ Pa or more, and particularly preferably It is 8.0×10 ⁸ Pa or more, and most preferably 1.0×10 ⁹ Pa or more. Typically, the upper limit of the Young's modulus of the base material layer at 23°C is preferably 1.0×10 ¹¹ Pa or less. If the Young's modulus of the base layer at 23°C is within the above range, the effects of the present invention can be more expressed. If the Young's modulus of the base layer at 23°C is too low, if the adhesive film is bent at an angle, there is a risk that the tension on the outer diameter side cannot be sufficiently maintained relative to the compression on the inner diameter side, and the thickness tends to change, causing damage. There is a risk that excitation from the complex may easily occur. If the Young's modulus of the base layer at 23°C is too high, there is a risk that the adhesive film cannot be easily deformed. The method of measuring Young's modulus will be explained in detail later.

As a material for the base layer, any suitable material can be adopted as long as it does not impair the effect of the present invention. Representative materials for such a base layer include resin materials.

Resin materials used as materials for the base layer include, for example, polyimide (PI), polyetheretherketone (PEEK), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), poly Acrylic resins such as methyl methacrylate (PMMA), polycarbonate, triacetylcellulose (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), fluorine resin, cyclic olefin polymer, etc. I can hear it.

The resin material used as the material for the base material layer is preferably at least one selected from polyimide (PI), polyether ether ketone (PEEK), and cyclic olefin polymers because it can further express the effects of the present invention. and, more preferably, at least one selected from polyimide (PI) and polyetheretherketone (PEEK).

≪Adhesive layer≫

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

The adhesive force of the adhesive layer to the glass plate at 23°C, tensile speed of 300 mm/min, and 180 degree peel is preferably 1 N/25 mm or more, more preferably 5 N/25 mm or more, and still more preferably It is 10N/25mm or more, especially preferably 12N/25mm or more, and most preferably 15N/25mm or more. The upper limit of the adhesive force of the adhesive layer to the glass plate at 23°C, tensile speed of 300 mm/min, and 180 degree peel is typically preferably 1000 N/25 mm or less, and more preferably 5000 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 of the adhesive layer to the glass plate at 23°C, tensile speed of 300 mm/min, and 180 degree peel is within the above range, the effect of the present invention can be more expressed.

The adhesive layer contains a base polymer. The number of base polymers may be one, or two or more types may be used. The content ratio 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 even more preferable, since the effect of the present invention can be more expressed. Typically, it is 40% by weight to 90% by weight, particularly preferably 45% by weight to 85% by weight, and most preferably 50% by weight to 80% by weight.

As the base polymer, any suitable polymer can be employed as long as it does not impair the effect of the present invention. Since the effect of the present invention can be further expressed, the base polymer is preferably at least one selected from acrylic polymers, rubber polymers, silicone polymers, and urethane polymers. That is, the adhesive layer preferably contains at least one selected from the group consisting of an acrylic adhesive containing an acrylic polymer, a rubber-based adhesive containing a rubber-based polymer, a silicone-based adhesive containing a silicone-based polymer, and a urethane-based adhesive containing a urethane-based polymer. Since the effect of the present invention can be further exhibited, the adhesive layer preferably contains an acrylic adhesive. Hereinafter, as a representative example of an adhesive that can be included in the adhesive layer, an acrylic adhesive will be described in detail.

<Acrylic adhesive>

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

When the acrylic adhesive contains an acrylic polymer, a tackifier resin, and a crosslinking agent, the content ratio of the total amount of the acrylic polymer, the tackifier resin, and the crosslinking agent relative to the total amount of the acrylic adhesive can be used to further express the effect of the present invention. Preferably it is 95% by weight or more, more preferably 97% by weight or more, and even more preferably 99% by weight or more.

(Acrylic polymer)

As an acrylic polymer, for example, a polymer of a monomer component that contains an alkyl (meth)acrylate as a main monomer and may further contain a secondary monomer copolymerizable with the main monomer is preferable. Here, the main monomer refers to a component that accounts for more than 50% by weight of the total monomer component.

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

CH ₂ =C(R ¹ )COOR ² (1)

Here, R ¹ in the formula (1) is a hydrogen atom or a methyl group, and R ² is a chain alkyl group having 1 to 20 carbon atoms (hereinafter, this range of carbon atoms may be referred to as “C1-20”). am. From the viewpoint of the storage modulus of the adhesive layer and the like, R ² is preferably a C1-14 chain alkyl group, more preferably a C2-10 chain alkyl group, and still more preferably a C4-8 chain alkyl group. Here, chain shape includes straight chain shape and branched shape.

Examples of the alkyl (meth)acrylate where 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)acrylate 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. I can hear it. The number of these alkyl (meth)acrylates may be one, or two or more types may be used.

As alkyl (meth)acrylate, n-butylacrylate (BA) and 2-ethylhexyl acrylate (2EHA) are preferred because the effects of the present invention can be more expressed.

The content ratio of alkyl (meth)acrylate in the total monomer components used in the synthesis of acrylic polymer is preferably 70% by weight or more, more preferably 85% by weight, because the effect of the present invention can be more expressed. It is % by weight or more, and more preferably, it is 90 % by weight or more. The upper limit of the content of alkyl (meth)acrylate is preferably 99.5% by weight or less, more preferably 99% by weight or less. However, the acrylic polymer may be obtained by substantially polymerizing only alkyl (meth)acrylate.

When using an alkyl (meth)acrylate where R ² is a C4-8 chain alkyl group, among the alkyl (meth)acrylates contained in the monomer component, R ² is a C4-8 chain alkyl group. The ratio is preferably 50% by weight or more, more preferably 70% by weight or more, further preferably 90% by weight or more, and particularly preferably 95% by weight, in order to further express the effect of the present invention. It is % by weight or more, and most preferably 99% by weight to 100% by weight.

One embodiment of the acrylic polymer includes an acrylic polymer in which 50% by weight or more of the total monomer component is n-butylacrylate (BA). In this case, the content ratio of n-butylacrylate (BA) in all monomer components is preferably more than 50% by weight and 100% by weight or less, and is more preferable because the effect of the present invention can be more expressed. Preferably it is 55% by weight to 95% by weight, more preferably 60% by weight to 90% by weight, particularly preferably 63% by weight to 85% by weight, and most preferably 65% by weight to 80% by weight. The total monomer component may further contain 2-ethylhexyl acrylate (2EHA) in a smaller proportion than n-butylacrylate (BA).

One embodiment of the acrylic polymer includes an acrylic polymer in which less than 50% by weight of the total monomer component is 2-ethylhexyl acrylate (2EHA). In this case, the content ratio of 2-ethylhexyl acrylate (2EHA) in all monomer components is preferably greater than 0% by weight and 48% by weight or less, since the effect of the present invention can be more expressed. Preferably it is 5% by weight to 45% by weight, more preferably 10% by weight to 43% by weight, particularly preferably 15% by weight to 40% by weight, and most preferably 20% by weight to 35% by weight. . All monomer components may further contain n-butylacrylate (BA) in a larger proportion than 2-ethylhexyl acrylate (2EHA).

The acrylic polymer may be copolymerized with other monomers as long as the effect of the present invention is not impaired. Other monomers can be used for purposes such as adjusting the glass transition temperature (Tg) of the acrylic polymer and adjusting adhesion performance. For example, monomers that can improve the cohesion or heat resistance of the adhesive include monomers containing sulfonic acid groups, monomers containing phosphoric acid groups, monomers containing cyano groups, vinyl esters, aromatic vinyl compounds, etc., with vinyl esters being preferred. . Specific examples of vinyl esters include vinyl acetate (VAc), vinyl propionate, and vinyl laurate, with vinyl acetate (VAc) being preferred.

The number of “other monomers” may be one, or two or more types may be used. The content ratio of other monomers in the total monomer component is preferably 0.001% by weight to 40% by weight, more preferably 0.01% by weight to 40% by weight, and still more preferably 0.1% by weight to 10% by weight, Particularly preferably, it is 0.5% by weight to 5% by weight, and most preferably, it is 1% by weight to 3% by weight.

Other monomers that introduce a functional group that can serve as a crosslinking point into an acrylic polymer or contribute to the improvement of adhesion include, for example, a hydroxyl group (OH group)-containing monomer, a carboxyl group-containing monomer, an acid anhydride group-containing monomer, and an amide group. Containing monomers, amino group-containing monomers, imide group-containing monomers, epoxy group-containing monomers, (meth)acryloylmorpholine, vinyl ethers, etc. are mentioned.

As one embodiment of the acrylic polymer, an acrylic polymer in which a carboxyl group-containing monomer is copolymerized as another monomer can be mentioned. Examples of carboxylic acid-containing monomers include acrylic acid (AA), methacrylic acid (MAA), carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid. etc. can be mentioned. Among these, from the point of view of being able to further express the effect of the present invention, preferred examples of the carboxyl group-containing monomer include acrylic acid (AA) and methacrylic acid (MAA), and more preferably acrylic acid (AA). .

When employing a carboxyl group-containing monomer as the other monomer, the content ratio of the other monomer in the total monomer component is preferably 0.1% by weight to 10% by weight, since the effect of the present invention can be more expressed. Preferably it is 0.2% by weight to 8% by weight, more preferably 0.5% by weight to 5% by weight, particularly preferably 0.7% by weight to 4% by weight, and most preferably 1% by weight to 3% by weight. .

As one embodiment of the acrylic polymer, an acrylic polymer in which a hydroxyl group-containing monomer is copolymerized as another monomer can be mentioned. Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate. Hydroxyalkyl (meth)acrylates such as hydroxybutyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate; polypropylene glycol mono(meth)acrylate; N-hydroxyethyl (meth)acrylamide; etc. can be mentioned. Among these, the hydroxyl group-containing monomer is preferably a hydroxyalkyl (meth)acrylate in which the alkyl group is a straight chain having 2 to 4 carbon atoms, since it can further exhibit the effect of the present invention. Examples of these include 2-hydroxyethyl acrylate (HEA) and 4-hydroxybutylacrylate (4HBA), and more preferably, 4-hydroxybutylacrylate (4HBA).

When employing a hydroxyl group-containing monomer as the other monomer, the content ratio of the other monomer in the total monomer component is preferably 0.001% by weight to 10% by weight, since the effect of the present invention can be more expressed. Preferably it is 0.01% by weight to 5% by weight, more preferably 0.02% by weight to 2% by weight, particularly preferably 0.03% by weight to 1% by weight, and most preferably 0.05% by weight to 0.5% by weight. .

The Tg of the base polymer may be, for example, -80°C or higher to enable the effects of the present invention to be more expressed. The base polymer (preferably an acrylic polymer) is designed to have a Tg of preferably -15°C or lower from the viewpoint of increasing the deformability of the adhesive layer in the shear direction. In some embodiments, the Tg of the base polymer is, for example, preferably -25°C or lower, more preferably -40°C or lower, and even more preferably -50°C or lower. The Tg of the base polymer is designed so that, for example, the Tg is preferably -70°C or higher (more preferably -65°C or higher, and even more preferably -60°C or higher) from the viewpoint of improving cohesiveness and shape recovery. It is done.

The Tg of the base polymer is a value obtained from Fox's equation based on the Tg of the homopolymer (homopolymer) of each monomer constituting the base polymer and the weight fraction (copolymerization ratio by weight) of the monomer. says As shown below, Fox's equation is a relationship between the Tg of a copolymer and the glass transition temperature Tgi of a homopolymer obtained by independently polymerizing each of the monomers constituting the copolymer.

1/Tg=Σ(Wi/Tgi)

In the Fox equation, Tg is the glass transition temperature of the copolymer (unit: K), Wi is the weight fraction of monomer i in the copolymer (copolymerization ratio by weight), and Tgi is the homopolymer of monomer i. Indicates the glass transition temperature (unit: K). As the Tg of the homopolymer, the value described in known data is adopted.

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

2-Ethylhexyl acrylate -70℃

n-butylacrylate -55℃

Acrylic acid 106℃

2-Hydroxyethyl acrylate -15℃

4-Hydroxybutylacrylate -40℃

For homopolymer Tg other than those exemplified above, the values described in “Polymer Handbook” (3rd edition, John Wiley & Sons, Inc., 1989) can be used. When multiple numerical values are described in the above-mentioned “Polymer Handbook,” conventional values are adopted. For monomers not described in the above-mentioned “Polymer Handbook,” the catalog value of the monomer manufacturing company is adopted. As the homopolymer Tg of monomers that are not described in the above-mentioned "Polymer Handbook" and the catalog values of monomer manufacturers are not provided, the value obtained by the measurement method described in Japanese Patent Laid-Open No. 2007-51271 shall be used. .

As a method for obtaining the acrylic polymer, various polymerization methods known as methods for synthesizing acrylic polymers, such as solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization, can be appropriately employed. Among these polymerization methods, the solution polymerization method can be preferably used. As a monomer supply method when performing solution polymerization, a batch supply method in which the entire amount of the monomer component is supplied at once, a continuous supply (dropwise) method, a split supply (dropwise) method, etc. can be appropriately adopted. 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, further preferably 40°C or higher, and preferably 40°C or higher. Preferably it is 170°C or lower, more preferably 160°C or lower, and even more preferably 140°C or lower. Methods for obtaining an acrylic polymer include photopolymerization performed by irradiating light such as UV (typically performed in the presence of a photopolymerization initiator), or active energy rays such as radiation polymerization performed by irradiating radiation such as β-rays or γ-rays. Irradiation polymerization may be employed.

The solvent (polymerization solvent) used in solution polymerization can be appropriately selected from any suitable organic solvent. For example, aromatic compounds (typically aromatic hydrocarbons) such as toluene, acetic acid esters such as ethyl acetate, and aliphatic or alicyclic hydrocarbons such as hexane and cyclohexane.

The initiator (polymerization initiator) used for polymerization can be appropriately selected from any suitable polymerization initiator depending on the type of polymerization method. The number of polymerization initiators may be one, or two or more types may be used. Examples of such polymerization initiators include azo-based polymerization initiators such as 2,2'-azobisisobutyronitrile (AIBN); persulfate 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; etc. can be mentioned. Other examples of polymerization initiators include redox initiators made by combining a peroxide and a reducing agent.

The amount of the polymerization initiator used is preferably 0.005 parts by weight to 1 part by weight, more preferably 0.01 parts by weight to 1 part by weight, based on 100 parts by weight of all monomer components.

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

(Tackifying resin)

The acrylic adhesive may contain a tackifying resin because it can further exhibit the effects of the present invention. 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. , ketone-based tackifying resin, etc. The number of tackifying resins may be one, or two or more types may be used.

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, based on 100 parts by weight of the base polymer, in order to further realize the effect of the present invention. parts, more preferably 15 parts by weight to 50 parts by weight, further preferably 20 parts by weight to 45 parts by weight, particularly preferably 25 parts by weight to 40 parts by weight, and most preferably 25 parts by weight to 25 parts by weight. It is 35 parts by weight.

The tackifying resin preferably contains tackifying resin TL with a softening point of less than 105°C because the effect of the present invention can be more expressed. The tackifying resin TL can effectively contribute to improving the deformability of the adhesive layer in the plane direction (shear direction). From the viewpoint of obtaining a higher deformability improvement 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, and even more preferably 65°C. ℃ to 95℃, particularly preferably 70℃ to 90℃, and most preferably 75℃ to 85℃.

The softening point of the tackifying resin is defined as a value measured based on the softening point test method (ring and ball method) specified in JIS K5902 and JIS K2207. Specifically, the sample is melted as quickly as possible at the lowest temperature possible, and then filled into a ring placed on a flat metal plate, being careful to avoid generating bubbles. After cooling, cut off the raised portion from the plane containing the top of the ring with a slightly heated penknife. Next, the support vessel (bath) is placed 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 the depth is 90 mm or more. Next, the steel ball (9.5 mm in diameter, 3.5 g in weight) and the ring filled with the sample are immersed in glycerin without contacting each other, and the temperature of the glycerin is maintained at 20°C plus or minus 5°C for 15 minutes. Next, a steel ball is placed on the center of the surface of the sample in the ring and placed in a fixed position on the support. Next, the distance from the top of the ring to the glycerin surface is maintained at 50 mm, a thermometer is placed, the center of the mercury sphere of the thermometer is set at the same height as the center of the ring, and the container is heated. 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 ensure even heating. Additionally, the rate at which the bath temperature rises after heating starts and reaches 40°C must be 5.0 plus or minus 0.5°C per minute. The sample gradually softens and flows down from the ring, and the temperature when it finally contacts the base plate is read and this is taken as the softening point. Two or more softening points are measured simultaneously, and the average value is adopted.

The amount of tackifying resin TL used is preferably 5 parts by weight to 50 parts by weight, more preferably 10 parts by weight to 45 parts by weight, based on 100 parts by weight of the base polymer, since the effect of the present invention can be more expressed. Parts by weight, more preferably 15 parts by weight to 40 parts by weight, particularly preferably 20 parts by weight to 35 parts by weight, and most preferably 25 parts by weight to 32 parts by weight.

As the tackifying resin TL, among the tackifying resins exemplified above, one or two or more types appropriately selected from those having a softening point of less than 105°C can be employed. The tackifying resin TL preferably contains a rosin-based resin.

Examples of rosin-based resins that can be preferably used as the tackifying resin TL include rosin esters such as unmodified rosin ester and modified rosin ester. Examples of modified rosin ester include hydrogenated rosin ester.

The tackifying resin TL preferably contains hydrogenated rosin ester because it can further express the effects of the present invention. As a hydrogenated rosin ester, the softening point is preferably less than 105°C, more preferably 50°C to 100°C, and still more preferably 60°C to 90°C, since the effect of the present invention can be more expressed. , particularly preferably 70°C to 85°C, and most preferably 75°C to 85°C.

The tackifying resin TL may contain non-hydrogenated rosin ester. Here, non-hydrogenated rosin ester is a concept that comprehensively refers to things other than hydrogenated rosin ester among the above-mentioned rosin esters. Non-hydrogenated rosin esters include undenatured rosin esters, disproportionated rosin esters, and polymerized rosin esters.

As a non-hydrogenated rosin ester, the softening point is preferably less than 105°C, more preferably 50°C to 100°C, and even more preferably 60°C to 90°C, in order to better express the effects of the present invention. ℃, particularly preferably 70 ℃ to 85 ℃, and most preferably 75 ℃ to 85 ℃.

The tackifying resin TL may contain other tackifying resins in addition to the rosin-based resin. As another tackifying resin, one or two or more types appropriately selected from those having a softening point of less than 105° C. among the tackifying resins exemplified above can be employed. The tackifying resin TL may contain, for example, a rosin-based resin and a terpene resin.

The content ratio of the rosin-based resin in the entire tackifying resin TL is preferably greater than 50% by weight, and more preferably 55% by weight to 100% by weight, since the effect of the present invention can be more expressed. , more preferably 60% by weight to 99% by weight, particularly preferably 65% by weight to 97% by weight, and most preferably 75% by weight to 97% by weight.

Since the effect of the present invention can be further expressed, the tackifying resin may contain a combination of tackifying resin TL and tackifying resin TH having a softening point of 105°C or higher (preferably 105°C to 170°C). do.

As the tackifying resin TH, one or two or more types appropriately selected from those with a softening point of 105°C or higher among the tackifying resins exemplified above can be employed. The tackifying resin TH may include at least one selected from rosin-based tackifying resins (for example, rosin esters) and terpene-based tackifying resins (for example, terpene phenol resin).

(Cross-linking agent)

Acrylic adhesives may contain a crosslinking agent. The number of crosslinking agents may be one, or two or more types may be used. By using a crosslinking agent, an appropriate cohesive force can be imparted to the acrylic adhesive. The cross-linking agent can also be helpful in controlling the displacement distance and return distance in the holding capacity test. An acrylic adhesive containing a crosslinking agent can be obtained, for example, by forming an adhesive layer using an adhesive composition containing the crosslinking agent. The crosslinking agent may be included in the acrylic adhesive in the form after the crosslinking reaction, in the form before the crosslinking reaction, in a partially crosslinked form, or in an intermediate or complex form thereof. The crosslinking agent is typically contained in the acrylic adhesive only in the form after the crosslinking reaction.

The amount of the crosslinking agent used is preferably 0.005 parts by weight to 10 parts by weight, more preferably 0.01 parts by weight to 7 parts by weight, based on 100 parts by weight of the base polymer, in order to further realize the effect of the present invention. , more preferably 0.05 parts by weight to 5 parts by weight, particularly preferably 0.1 parts by weight to 4 parts by weight, and most preferably 1 part by weight to 3 parts by weight.

Examples of the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, silicone-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, silane-based crosslinking agents, alkyl etherified melamine-based crosslinking agents, metal chelate-based crosslinking agents, and crosslinking agents such as peroxides. Since the effect of the present invention can be more expressed, isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferred, and isocyanate-based crosslinking agents are more preferred.

The isocyanate-based crosslinking agent can be a compound having two or more isocyanate groups (including isocyanate regenerative functional groups temporarily protected by blocking agents or quantization, etc.) in one molecule. Examples of the isocyanate-based crosslinking agent include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate; Alicyclic isocyanates such as isophorone diisocyanate; Aliphatic isocyanates such as hexamethylene diisocyanate; etc. can be mentioned.

More specifically, examples of the isocyanate-based crosslinking agent include lower aliphatic polyisocyanates 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 polyphenylisocyanate; Trimethylolpropane/tolylene diisocyanate trimer adduct (e.g., manufactured by Tosoh Corporation, brand name: Coronate L), trimethylolpropane/hexamethylene diisocyanate trimer adduct (e.g., manufactured by Tosoh Corporation, brand name: Coronate HL) ), isocyanate adducts such as the isocyanurate form of hexamethylene diisocyanate (for example, Tosoh Corporation, brand name: Coronate HX); Trimethylolpropane adduct of xylylene diisocyanate (e.g., manufactured by Mitsui Chemicals, brand name: Takenate D110N), trimethylolpropane adduct of xylylene diisocyanate (e.g., manufactured by Mitsui Chemicals, brand name: Takenate) Nate D120N), trimethylolpropane adduct of isophorone diisocyanate (e.g., manufactured by Mitsui Chemicals, brand name: Takenate D140N), trimethylolpropane adduct of hexamethylene diisocyanate (e.g., manufactured by Mitsui Chemicals) , product name: Takenate D160N); polyether polyisocyanate, polyester polyisocyanate, and adducts thereof with various polyols; polyisocyanates polyfunctionalized with isocyanurate bonds, biuret bonds, allophanate bonds, etc.; etc. can be mentioned. Among these, aromatic isocyanate and alicyclic isocyanate are preferable because they can achieve both deformability and cohesion in a good balance.

The amount of the isocyanate-based crosslinking agent used is preferably 0.005 parts by weight to 10 parts by weight, more preferably 0.01 parts by weight to 7 parts by weight, based on 100 parts by weight of the base polymer, in order to further demonstrate the effect of the present invention. parts, more preferably 0.05 parts by weight to 5 parts by weight, particularly preferably 0.1 parts by weight to 4 parts by weight, and most preferably 1 part by weight to 3 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 because the effect of the present invention can be more expressed. , more preferably 22 to 45, further preferably 25 to 40, particularly preferably 27 to 40, and most preferably 30 to 35.

When the acrylic adhesive contains a tackifying resin TL with a softening point of 105°C or lower, the weight ratio of the tackifying resin TL/isocyanate-based crosslinking agent is preferably greater than 2 and 15% because the effect of the present invention can be more expressed. It is less than, more preferably 5 to 13, still more preferably 7 to 12, and especially preferably 7 to 11.

As an epoxy-based crosslinking agent, a polyfunctional epoxy compound having two or more epoxy groups per molecule can be used. As an 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, etc. Commercially available epoxy-based crosslinking agents include, for example, the brand names “Tetrad C” and “Tetrad X” manufactured by Mitsubishi Gas Chemical Co., Ltd.

The amount of the epoxy-based crosslinking agent used is preferably 0.005 parts by weight to 10 parts by weight, more preferably 0.01 parts by weight to 5 parts by weight, based on 100 parts by weight of the base polymer, in order to further demonstrate the effects of the present invention. parts, more preferably 0.015 parts by weight to 1 part by weight, particularly preferably 0.15 parts by weight to 0.5 parts by weight, and most preferably 0.015 parts by weight to 0.3 parts by weight.

(Other ingredients)

If necessary, the acrylic adhesive may contain various additives common in the adhesive field, such as leveling agents, crosslinking aids, plasticizers, softeners, fillers, antistatic agents, anti-aging agents, ultraviolet absorbers, antioxidants, and light stabilizers. Regarding these various additives, conventionally known ones can be used by usual methods.

≪Antistatic layer≫

The adhesive film of the present invention may have an antistatic layer on the side opposite to the side of the base layer having the adhesive layer. By having the adhesive film of the present invention have an antistatic layer on the side opposite to the side with the adhesive layer of the base layer, charging of the adhesive film itself can be suppressed, dust becomes difficult to adsorb, and this is a preferable aspect.

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

Examples of the antistatic agent contained in the antistatic resin include cationic antistatic agents having cationic functional groups such as quaternary ammonium salts, pyridinium salts, and first, second, and third amino groups; Anionic antistatic agents having anionic functional groups such as sulfonates, sulfuric acid esters, phosphonates, and phosphoric acid esters; amphoteric antistatic agents such as alkyl betaine and its derivatives, imidazoline and its derivatives, and alanine and its derivatives; Nonionic antistatic agents such as amino alcohol and its derivatives, glycerin and its derivatives, polyethylene glycol and its derivatives; Ion conductive polymers obtained by polymerizing or copolymerizing monomers having the above cationic, anionic, or zwitterionic ion conductive groups; etc. can be mentioned. The number of these antistatic agents may be one, or two or more types may be used.

Cationic antistatic agents include, for example, those having quaternary ammonium groups such as alkyltrimethylammonium salt, acyloylamidopropyltrimethylammonium methosulfate, alkylbenzylmethylammonium salt, choline acyl chloride, and polydimethylaminoethyl methacrylate. Meth)acrylate copolymer; Styrene copolymers having quaternary ammonium groups such as polyvinylbenzyltrimethylammonium chloride; diallylamine copolymers having quaternary ammonium groups such as polydiallyldimethylammonium chloride; etc. can be mentioned. The number of these antistatic agents may be one, or two or more types may be used.

Examples of anionic antistatic agents include alkyl sulfonates, alkylbenzene sulfonates, alkyl sulfuric acid ester salts, alkyl ethoxy sulfuric acid ester salts, alkyl phosphoric acid ester salts, and styrene copolymers containing sulfonic acid groups. The number of these antistatic agents may be one, or two or more types may be used.

Examples of zwitterionic antistatic agents include alkyl betaine, alkylimidazolium betaine, and carbobetaine graft copolymerization. The number of these antistatic agents may be one, or two or more types may be used.

Nonionic antistatic agents include, for example, 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 alkyl phenyl ether, polyoxyethylene alkyl ether, polyethylene glycol, polyoxyethylene diamine, copolymer containing polyether, polyester, and polyamide, methoxypolyethylene glycol (meth)acrylate etc. can be mentioned. The number of these antistatic agents may be one, or two or more types may be used.

Examples of conductive polymers include polyaniline, polypyrrole, and polythiophene. The number of these conductive polymers may be one, or two or more types may be used.

Conductive materials include, for example, tin oxide, antimony oxide, indium oxide, cadmium oxide, titanium oxide, zinc oxide, indium, tin, antimony, gold, silver, copper, aluminum, nickel, chromium, titanium, iron, cobalt, and iodide. Copper and alloys or mixtures thereof may be included. The number of these conductive substances may be one, or two or more types may be used.

As the resin component used in the antistatic resin and the conductive resin, for example, general-purpose resins such as polyester resin, acrylic resin, polyvinyl resin, urethane resin, melamine resin, and epoxy resin are used. Additionally, 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 and as a crosslinking agent, methylolated or alkylolated melamine-based compounds, urea-based compounds, glyoxal-based compounds, and acrylamide-based compounds; epoxy compounds; isocyanate compounds; It is also possible to contain etc.

As a method of forming the antistatic layer, for example, the antistatic resin, conductive polymer, conductive resin, etc. described above are diluted with a solvent such as an organic solvent or water, and the coating solution is applied to a substrate or the like and dried.

Diluted solutions used to form the antistatic layer include, for example, methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexanone, n-hexane, toluene, xylene, methanol, ethanol, n-propanol, Isopropanol, water, etc. can be mentioned. The number of these solvents may be one, and two or more types may be used.

Regarding the application method in forming the antistatic layer, any suitable application method may be appropriately used. Examples of such application methods include roll coating, gravure coating, reverse coating, roll brush, spray coating, air knife coating, impregnation, and curtain coating.

As a method of depositing or plating the conductive material, any suitable method can be appropriately used. Examples of such methods include vacuum deposition, sputtering, ion plating, chemical vapor deposition, spray pyrolysis, chemical plating, and electroplating.

The thickness of the antistatic layer can be any appropriate thickness within a range that does not impair the effect of the present invention. In order to further realize the effect of the present invention, the thickness of the antistatic layer is preferably 0.001 μm to 5 μm, and more preferably 0.005 μm to 1 μm.

≪Top coating layer≫

The adhesive film of the present invention may have a top coating layer on the side opposite to the side of the base layer having the adhesive layer. The top coating layer preferably contains a binder, and more preferably contains a binder and a lubricant. When the adhesive film of the present invention has a top coating layer, the scratch resistance of the adhesive film improves and becomes a preferred embodiment.

<Binder>

The binder may be any suitable resin as long as it does not impair the effect of the present invention. As such a resin, it is preferably at least one selected from the group containing polyester resins and urethane resins since it can further express the effects of the present invention.

(polyester resin)

When a polyester resin is contained in the binder, only one type of polyester resin may be used, and two or more types may be used.

The polyester resin is preferably a resin containing polyester as a main component. The content ratio of polyester in the polyester resin is preferably more than 50% by weight, more preferably 75% by weight or more, and even more preferably 90% by weight or more.

The polyester is preferably selected from polyhydric carboxylic acids (preferably dicarboxylic acids) and their derivatives (anhydrides, esters, halides, etc. of polyhydric carboxylic acids) having two or more carboxyl groups in one molecule. Condensation of 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. It has one structure.

Compounds that can be employed as polyhydric carboxylic acid components include, for example, oxalic acid, malonic acid, difluoromalonic acid, alkylmalonic acid, succinic acid, tetrafluorosuccinic acid, alkylsuccinic acid, (±)-malic acid, and meso-tartaric acid. , itaconic acid, maleic acid, methylmaleic acid, fumaric acid, methylfumaric acid, acetylenedicarboxylic acid, glutaric acid, hexafluoroglutaric acid, methylglutaric acid, glutaconic acid, adipic acid, dithioadipic acid. , methyladipic acid, dimethyladipic acid, tetramethyladipic acid, methyleneadipic 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 acids (e.g., 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid), 1,4-(2-norbornene)dicarboxylic acid, Alicyclic dicarboxylic acids such as 5-norbornene-2,3-dicarboxylic acid (hymic acid), adamantane dicarboxylic acid, and 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, oxofluorenedica Ruboxylic acid, anthracenedicarboxylic acid, biphenyldicarboxylic acid, biphenylenedicarboxylic acid, dimethylbiphenylenedicarboxylic acid, 4,4"-p-terephenylenedicarboxylic acid, 4 ,4"-p-quarterphenyldicarboxylic acid, bibenzyldicarboxylic acid, azobenzenedicarboxylic acid, homophthalic acid, phenylenediacetic acid, phenylenedipropionic acid, naphthalenedicarboxylic acid, naphthalenedipropionic acid, biphenyl diacetic acid, biphenyldipropionic acid, 3,3'-[4,4'-(methylenedi-p-biphenylene)dipropionic acid, 4,4'-bibenzyldiacetic acid, 3,3'(4,4 Aromatic dicarboxylic acids such as '-bibenzyl)dipropionic acid and oxydi-p-phenylene diacetic acid; An acid anhydride of any of the above-mentioned polyhydric carboxylic acids; Ester of any of the above-mentioned polyhydric carboxylic acids (e.g., alkyl ester, monoester, diester, etc.); Acid halides (for example, dicarboxylic acid chloride, etc.) corresponding to any of the above-mentioned polyhydric carboxylic acids; etc. can be mentioned.

Suitable examples of compounds that can be employed as the polyhydric carboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid, and their acid anhydrides; 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 their acid anhydrides; lower alkyl esters of the above dicarboxylic acids (for example, esters with monoalcohols having 1 to 3 carbon atoms); etc. can be mentioned.

Compounds that can be employed as the polyhydric alcohol component include, for example, 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, bisphenol A, etc. can be mentioned. 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 (e.g., at least one selected from hydrophilic functional groups such as a sulfonic acid metal base, carboxyl group, ether group, and phosphoric acid group) into the polymer. You can. In this way, methods for introducing a hydrophilic functional group into a polymer include, for example, a method of copolymerizing a compound having a hydrophilic functional group, polyester or its precursor (e.g., polyhydric carboxylic acid component, polyhydric alcohol component, oligomers thereof, etc. ) can be appropriately adopted by any appropriate method, such as a method of generating a hydrophilic functional group by denaturing a hydrophilic functional group. Preferred water-dispersible polyesters include polyesters in which a compound having a hydrophilic functional group is copolymerized (copolymerized polyester).

The polyester resin used as a binder may have saturated polyester as its main component, or may have unsaturated polyester as its main component. The polyester resin is preferably a saturated polyester as its main component, and more preferably a saturated polyester imparted with water dispersibility (for example, saturated copolyester). These polyester resins (polyester resins that may be prepared in the form of aqueous dispersions) can be synthesized by any suitable method, or commercial products can be easily obtained.

The molecular weight of the polyester resin is the weight average molecular weight (Mw) in terms of standard polystyrene measured by gel permeation chromatography (GPC), and is preferably 0.5 × 10 ⁴ to 15 × 10 ⁴ , more preferably 1 It is 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-based resin is contained in the binder, only one type of the urethane-based resin may be used, and two or more types may be used.

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 polyol (A), only one type may be used, and two or more types may be used.

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

As the polyol (A), glycol such as ethylene glycol or propylene glycol, which has two or more OH groups, is preferably used as an essential component. By employing glycol as an essential component in this way, it is possible to provide, for example, a urethane-based cured resin that has excellent strength of the coated film after curing and is excellent in adhesion to the substrate and retention of additive substances. The glycol content in the polyol (A) is preferably 30% by weight to 100% by weight, more preferably 50% by weight to 100% by weight, and still more preferably 70% by weight to 100% by weight, More preferably, it is 90% by weight to 100% by weight, particularly preferably 95% by weight to 100% by weight, and most preferably substantially 100% by weight.

Examples of polyol (A) include ethylene glycol, diethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, and 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, Examples include polyether polyol, polycaprolactone polyol, polycarbonate polyol, and castor oil-based polyol.

Polyester polyol can be obtained, for example, by esterification reaction between a polyol component and an acid component.

Examples of acid components include succinic acid, methylsuccinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecandioic 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, their acid anhydrides, etc. are mentioned.

Examples of polyether polyols include water, low-molecular-weight polyols (propylene glycol, ethylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc.), bisphenols (bisphenol A, etc.), dihydroxybenzenes (catechol, resorcinol, etc.) and polyether polyol obtained by addition polymerizing alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide using hydroquinone, etc., as an initiator. Specifically, examples include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

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

Examples of polycarbonate polyol include polycarbonate polyol obtained by subjecting the polyol component and phosgene to a polycondensation reaction; The polyol component and dicarbonate such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, ethylbutyl carbonate, ethylene carbonate, propylene carbonate, diphenyl carbonate, and dibenzyl carbonate. polycarbonate polyol obtained by transesterification of esters; Copolymerized polycarbonate polyol obtained by using two or more of the above polyol components in combination; Polycarbonate polyols obtained by esterifying the various polycarbonate polyols and carboxyl group-containing compounds described above; Polycarbonate polyols obtained by etherifying the various polycarbonate polyols and hydroxyl group-containing compounds described above; Polycarbonate polyol obtained by transesterifying the various polycarbonate polyols and ester compounds described above; Polycarbonate polyols obtained by transesterifying the various polycarbonate polyols and hydroxyl group-containing compounds described above; Polyester-based polycarbonate polyol obtained by polycondensation reaction of the various polycarbonate polyols and dicarboxylic acid compounds described above; Copolymerized polyether-based polycarbonate polyol obtained by copolymerizing the various polycarbonate polyols and alkylene oxide described above; etc. can be mentioned.

Examples of castor oil-based polyol include castor oil-based polyol obtained by reacting castor oil fatty acid with the polyol component. Specifically, for example, castor oil-based polyol obtained by reacting castor oil fatty acid with polypropylene glycol is mentioned.

The number of polyfunctional isocyanate compounds (B) may be one, and two or more types may be used.

As the polyfunctional isocyanate compound (B), any appropriate polyfunctional isocyanate compound that can be used in the urethanization reaction can be employed. Examples of such polyfunctional isocyanate compounds (B) include polyfunctional aliphatic isocyanate compounds, polyfunctional alicyclic isocyanates, and polyfunctional aromatic isocyanate compounds.

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

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

Examples of polyfunctional aromatic diisocyanate compounds 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. there is.

Examples of the polyfunctional isocyanate compound (B) include the trimethylolpropane adduct form, the biuret form reacted with water, and the trimer having an isocyanurate ring of the various polyfunctional isocyanate compounds described above. Additionally, these may be used together.

The content ratio of the polyfunctional isocyanate compound (B) is preferably 5% to 60% by weight, more preferably 8% to 60% by weight, relative to the polyol (A). %, and more preferably 10% by weight to 60% by weight. By adjusting the content ratio of the polyfunctional isocyanate compound (B) within the above range, the effects of the present invention can be further exhibited.

Urethane-based resin is typically obtained by curing a composition containing a polyol (A) and a polyfunctional isocyanate compound (B). This composition may contain any appropriate other components other than the polyol (A) and the polyfunctional isocyanate compound (B) within the range that does not impair the effect of the present invention. These other components include, for example, catalysts, resin components other than polyurethane resins, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, thin substances, softeners, plasticizers, anti-aging agents, conductive agents, and antioxidants. , ultraviolet absorbers, light stabilizers, surface lubricants, leveling agents, corrosion inhibitors, heat-resistant stabilizers, polymerization inhibitors, lubricants, solvents, etc.

Methods for obtaining a urethane-based resin by curing a composition containing a polyol (A) and a polyfunctional isocyanate compound (B) include a urethanization reaction method using bulk polymerization or solution polymerization, etc., as long as the effect of the present invention is not impaired. Any suitable method may be employed.

(Other resins)

The top coating layer may contain other resins (e.g., acrylic resin, acrylic-styrene resin, acrylic-silicone resin, silicone resin) other than polyester resin and urethane resin as a binder, as long as the performance of the adhesive film is not significantly impaired. , at least one type of resin selected from polysilazane resin, fluorine resin, and polyolefin resin). In a preferred embodiment of the top coating layer, the binder of the top coating layer substantially contains only at least one selected from the group containing polyester resin and urethane resin, and the binder occupies a binder selected from the group containing polyester resin and urethane resin. The proportion of at least one type 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 top coating layer is preferably 15% by weight to 95% by weight, and more preferably 25% by weight to 80% by weight.

<Active>

The lubricant preferably contains an ester of a higher fatty acid and a higher alcohol (hereinafter sometimes referred to as “wax ester”).

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

A “higher alcohol” is preferably an alcohol having 6 or more carbon atoms, more preferably 10 or more carbon atoms, and even more preferably 10 to 40 carbon atoms. The alcohol is preferably a monohydric or dihydric alcohol, and more preferably a monohydric alcohol.

A top coating layer composed of a combination of such wax ester and the above-described binder is unlikely to whiten even when maintained under high temperature and high humidity conditions. Therefore, an adhesive film provided with a base material having such a top coating layer can have a higher appearance quality.

The following reasons are considered to be the reason why excellent whitening resistance (for example, a property that is difficult to whiten even when maintained under high temperature and high humidity conditions) is realized by the top coating layer of the above composition. In other words, it is presumed that the silicone-based lubricant used conventionally exerts the function of imparting slipperiness to the surface of the top coating layer by bleeding it. However, the degree of bleed of these silicone-based lubricants tends to vary due to differences in storage conditions (temperature, humidity, aging, etc.). For this reason, for example, when maintained under normal storage conditions (e.g., 25°C, 50% RH), the adhesive film maintains adequate slipperiness over a relatively long period of time (e.g., about 3 months) immediately after production. If the amount of silicone-based lubricant used is set to obtain this, when this adhesive film is stored for two weeks under high temperature and high humidity conditions (for example, 60°C, 95% RH), excessive bleeding of the lubricant occurs. There is a risk that the silicone-based lubricant that bleeds excessively in this way will whiten the top coating layer (and eventually the adhesive film).

As a preferred embodiment of the top coating layer, a specific combination of wax ester as a lubricant and polyester resin as a binder is employed. According to this combination of lubricant and binder, the degree of bleeding from the wax ester top coating layer is less likely to be affected by storage conditions. Thereby, the whitening resistance of the adhesive film can be improved.

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

X-COO-Y (W)

In the formula (W), , and particularly preferably 20 to 32. If the above number of carbon atoms is too small, there is a risk that the effect of providing slipperiness to the top coating layer may be insufficient. The above hydrocarbon group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. The above hydrocarbon group is preferably a saturated hydrocarbon group. In addition, the above hydrocarbon group may be a structure containing an aromatic ring, may be a structure not containing an aromatic ring (aliphatic hydrocarbon group), or may be a hydrocarbon group having a structure containing an aliphatic ring (alicyclic hydrocarbon group). It may be a chain-shaped (including straight-chain and branched-chain) hydrocarbon.

The wax ester is a compound in which It is an alkyl compound. Specific examples of such compounds include, for example, myricyl cerote (CH ₃ (CH ₂ ) ₂₄ COO(CH ₂ ) ₂₉ CH ₃ ), myricyl 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. You can.

The melting point of the wax ester is preferably 50°C or higher, more preferably 60°C or higher, further preferably 70°C or higher, and particularly preferably 75°C or higher. With these wax esters, higher whitening resistance can be realized. The wax ester preferably has a melting point of 100°C or lower. Since these wax esters have a high slipperiness effect, they can form a top coating layer with higher scratch resistance. It is also preferable that the melting point of the wax ester is 100°C or lower because it makes it easy to prepare an aqueous dispersion of the wax ester. As such a wax ester, for example, myricyl cerotate can be preferably employed.

As a raw material for the top coating layer, natural wax containing such wax ester can be used. As such a natural wax, the content ratio of the above-mentioned wax esters (if two or more types of wax esters are included, the total content ratio thereof) is preferably greater than 50% by weight, and more preferably, based on non-volatile matter (NV). It is preferably 65% by weight or more, and more preferably 75% by weight or more. Such natural waxes include, for example, carnauba wax (generally containing myricyl cerotiate in a proportion of preferably 60% by weight or more, more preferably 70% by weight or more, and even more preferably 80% by weight or more). ), vegetable wax such as palm wax; Animal waxes such as beeswax and spermaceti; etc. can be mentioned. The melting point of this natural wax is preferably 50°C or higher, more preferably 60°C or higher, further preferably 70°C or higher, and particularly preferably 75°C or higher. As a raw material for the top coating layer, a chemically synthesized wax ester may be used, or a natural wax purified to increase the purity of the wax ester may be used. The number of these raw materials may be one, or two or more types may be used.

The proportion of the lubricant in the entire top coating layer is preferably 5% by weight to 50% by weight, and more preferably 10% by weight to 40% by weight. If the content ratio of the lubricant is too small, there is a risk that scratch resistance will easily decrease. If the content of the lubricant is too large, there is a risk that the effect of improving whitening resistance will be insufficient.

The top coating layer may contain another lubricant in addition to the wax ester. Other lubricants include various types of wax esters other than wax esters, such as petroleum wax (paraffin wax, etc.), mineral wax (montan wax, etc.), higher fatty acids (cerotic acid, etc.), and neutral fats (palmitic acid triglyceride, etc.). Examples include wax. Additionally, it may be added to the wax ester to contain a silicone-based lubricant, a fluorine-based lubricant, etc. A preferred embodiment of the top coating layer is one that substantially does not contain a silicone-based lubricant or a fluorine-based lubricant. For example, the total content of the silicone-based lubricant and the fluorine-based lubricant is preferably 0.01% by weight or less of the entire topcoat layer, and is more preferred. It is below the detection limit.

The top coating layer may contain antistatic ingredients, crosslinking agents, antioxidants, colorants (pigments, dyes, etc.), fluidity modifiers (thixotropic agents, thickeners, etc.), film forming aids, surfactants (defoaming agents, dispersants, etc.), preservatives, etc., as needed. May contain additives.

<Antistatic component of top coating layer>

A preferred embodiment of the top coating layer contains an antistatic component. The antistatic component is a component that can exert the effect of preventing or suppressing electrification of the adhesive film. When the top coating layer contains an antistatic component, for example, organic or inorganic conductive substances, various antistatic agents, etc. can be used as the antistatic component. It is also possible to use an antistatic agent that can be used in the antistatic layer described above.

Examples of the organic conductive material include quaternary ammonium salts, pyridinium salts, and cationic antistatic agents having cationic functional groups such as first amino group, second amino group, and third amino group; Anionic antistatic agents having anionic functional groups such as sulfonates, sulfuric acid esters, phosphonates, and phosphoric acid esters; Zwitterionic antistatic agents such as alkylbetaine and its derivatives, imidazoline and its derivatives, and alanine and its derivatives; Nonionic antistatic agents such as amino alcohol and its derivatives, glycerin and its derivatives, polyethylene glycol and its derivatives; Ion conductive polymers obtained by polymerizing or copolymerizing monomers having the above cationic, anionic, or zwitterionic ion conductive groups (for example, quaternary ammonium bases); Conductive polymers such as polythiophene, polyaniline, polypyrrole, polyethyleneimine, and allylamine polymers; etc. can be mentioned. The number of such antistatic agents may be one, or two or more types may be used.

Inorganic conductive materials include, for example, 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. The number of these inorganic conductive substances may be one, or two or more types may be used.

Examples of antistatic agents include cationic antistatic agents, anionic antistatic agents, zwitterionic antistatic agents, nonionic antistatic agents, and ions obtained by polymerizing or copolymerizing monomers having ionic conductive groups of the above cationic, anionic, and zwitterionic types. Conductive polymers, etc. can be mentioned.

When the top coating layer contains an antistatic component, preferably the antistatic component includes an organic conductive material. As the organic conductive material, various conductive polymers can be preferably used. According to this configuration, both good antistatic properties and high scratch resistance can be achieved.

Examples of the conductive polymer include polythiophene, polyaniline, polypyrrole, polyethyleneimine, and allylamine polymers. The number of such conductive polymers may be one, or two or more types may be used. Additionally, it may be used in combination with other antistatic components (inorganic conductive substances, antistatic agents, 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, and even more preferably 3 parts by weight, based on 100 parts by weight of the binder included in the top coating layer. to 50 parts by weight. If the amount of the conductive polymer used is too small, there is a risk that the antistatic effect may be reduced. If the amount of the conductive polymer used is too large, the compatibility of the conductive polymer in the top coating layer may be insufficient, and there is a risk that the appearance quality of the top coating layer may be lowered or the solvent resistance may be lowered.

Preferred conductive polymers include polythiophene and polyaniline. As polythiophene, the weight average molecular weight Mw in terms of polystyrene is preferably 40×10 ⁴ or less, and more preferably 30×10 ⁴ or less. As for polyaniline, the weight average molecular weight Mw in terms of polystyrene is preferably 50×10 ⁴ or less, and more preferably 30×10 ⁴ or less. The weight average molecular weight Mw of the conductive polymer in terms of polystyrene is preferably 0.1×10 ⁴ or more, and more preferably 0.5×10 ⁴ or more. In addition, in this specification, polythiophene refers to a polymer of unsubstituted or substituted thiophene. Examples of substituted thiophene polymers include poly(3,4-ethylenedioxythiophene).

When a method of forming a top coating layer is adopted by applying a coating material for forming a top coating layer to a substrate and drying or curing it, the conductive polymer used to prepare the coating material is one in which the conductive polymer is dissolved or dispersed in water. One form (aqueous conductive polymer solution) can be preferably used. Such a conductive polymer aqueous solution can be prepared, for example, by dissolving or dispersing 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 the molecule) in water. Examples of the hydrophilic functional groups include sulfo group, amino group, amide group, imino group, hydroxyl group, mercapto group, hydrazino group, carboxyl group, quaternary ammonium group, sulfuric acid ester group (-O-SO ₃ H), and phosphoric acid ester group (e.g. For example, -O-PO(OH) ₂ ) and the like. This hydrophilic functional group may form a salt. Examples of commercially available polythiophene aqueous solutions include the “Denatron” series manufactured by Nagase Chemtech Co., Ltd. under the brand name. Examples of commercially available aqueous solutions of polyaniline sulfonic acid include "aqua-PASS" under the trade name of Mitsubishi Rayon Corporation.

In preparing the coating material, an aqueous polythiophene solution is preferably 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. Examples of commercially available polythiophene aqueous solutions include H.C.Stark's brand name "Baytron". In addition, when using an aqueous polythiophene solution containing PSS as described above, the total amount of polythiophene and PSS is preferably 5 to 200 parts by weight, more preferably 5 parts by weight to 200 parts by weight, based on 100 parts by weight of the binder. is 10 parts by weight to 100 parts by weight, and more preferably 25 parts by weight to 70 parts by weight.

The top coating layer may, if necessary, contain both a conductive polymer and one or more other antistatic components (organic conductive substances other than the conductive polymer, inorganic conductive substances, antistatic agents, etc.). Preferably, the top coating layer does not contain substantially any antistatic component other than the conductive polymer. That is, it is preferable that the antistatic component contained in the top coating layer consists substantially of only a conductive polymer.

<Cross-linking agent>

The top coating layer preferably contains a crosslinking agent. As the crosslinking agent, a crosslinking agent such as a melamine-based crosslinking agent, an isocyanate-based crosslinking agent, or an epoxy-based crosslinking agent used for crosslinking general resins can be appropriately selected and used. By using such a crosslinking agent, at least one of the following effects can be realized: improvement in scratch resistance, improvement in solvent resistance, improvement in print adhesion, and reduction in friction coefficient (i.e., improvement in slipperiness). Preferably, the cross-linking agent includes a melamine-based cross-linking agent. The crosslinking agent may be a top coating layer consisting substantially only of a melamine-based crosslinking agent (melamine-based resin) (that is, substantially containing no crosslinking agents other than the melamine-based crosslinking agent).

<One preferred form of top coating layer>

One preferred form of the top coating layer is one in which the material of the base layer is at least one selected from polyimide and polyetheretherketone, and the topcoat layer contains a binder containing a urethane resin and an antistatic component. In this way, by employing a binder containing a urethane-based resin as a binder for the antistatic component of the top coating layer, a top coating layer is formed by applying it to the surface of a base layer made of at least one material selected from polyimide and polyether ether ketone. The property becomes excellent, the appearance can be good, and excellent antistatic properties can be exhibited.

As a binder for the antistatic component of the top coating layer, a binder containing a polyester resin is often preferred. However, for a specific base material layer in which the material of the base layer is at least one selected from polyimide and polyetheretherketone, polyester resin is used as a binder. The affinity of the binder containing the ester resin may be low, and there is a risk that the appearance of the top coating layer after application and formation may deteriorate or that excellent antistatic properties may not be achieved. As described above, when the material of the base layer is at least one selected from polyimide and polyetheretherketone, and the top coating layer contains a binder containing a urethane resin and an antistatic component, the surface of the base layer The application formability of the top coating layer becomes excellent, and a good appearance can be obtained, as well as excellent antistatic properties.

<Formation of top coating layer>

The top coating layer can be suitably formed by a method that includes applying to a substrate a liquid composition (coating material for forming a top coating layer) in which the resin component and additives used as necessary are dispersed or dissolved in an appropriate solvent. For example, a method of applying and attaching the coating material to the first surface of the substrate, drying it, and performing a hardening treatment (heat treatment, ultraviolet treatment, etc.) as necessary can be preferably adopted. The NV (non-volatile matter) of the coating material is preferably 5% by weight or less, more preferably 0.05% by weight to 5% by weight, further preferably 0.05% by weight to 1% by weight, and particularly preferably 0.10% by weight. It is % by weight to 1% by weight. When forming a top coating layer with a small thickness, the NV of the coating material is preferably 0.05% by weight to 0.50% by weight, more preferably 0.10% by weight to 0.30% by weight. By using a low NV coating material in this way, a more uniform top coating layer can be formed.

The solvent constituting the coating material for forming the top coating layer is preferably one that can stably dissolve or disperse the top coating layer forming components. This solvent may be an organic solvent, water, or a mixed solvent thereof. Examples of organic solvents 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 ether (for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether) and dialkylene glycol monoalkyl ether; At least one type selected from the like can be mentioned. Preferably, the solvent constituting the coating material for forming the top coating layer is water or a mixed solvent containing water as a main component (for example, a mixed solvent of water and ethanol).

<Properties of top coating layer>

The thickness of the top coating layer is preferably 3 nm to 500 nm, more preferably 3 nm to 100 nm, and still more preferably 3 nm to 60 nm. If the thickness of the top coating layer is too large, there is a risk that the transparency (light transmittance) of the adhesive film may easily decrease. If the thickness of the top coating layer is too small, there is a risk that it will be difficult to form the top coating layer uniformly. For example, there is a risk that the thickness of the top coating layer will vary greatly depending on the location, and for this reason, the adhesive film There is a risk that unevenness may easily occur in the appearance.

The thickness of the top coating layer can be determined by observing a cross section of the top coating layer with a transmission electron microscope (TEM). For example, the target sample (a base material with a top coating layer, an adhesive film with a base material, etc.) is subjected to heavy metal dyeing for the purpose of clarifying the top coating layer, followed by resin embedding, followed by ultra-thin sectioning. The result obtained by performing TEM observation of the cross section of the sample can be preferably used as the thickness of the top coating layer. As the TEM, for example, a TEM (model "H-7650") manufactured by Hitachi Corporation can be used. In the examples described later, the cross-sectional image obtained under the conditions of acceleration voltage: 100 kV and magnification: 60,000 times is binarized, and then the cross-sectional area of the top coating is divided by the sample length in the field of view to determine the thickness of the top coating layer (in the field of view) average thickness) is actually measured. Additionally, if the top coating layer can be observed sufficiently clearly even without performing heavy metal dyeing, the heavy metal dyeing treatment may be omitted. Alternatively, a calibration curve can be created for the correlation between the thickness determined by TEM and the detection results by various thickness detection devices (e.g., surface roughness meter, interference thickness meter, infrared spectrometer, various X-ray diffraction devices, etc.) The thickness of the top coating layer may be obtained by performing calculation.

The surface resistivity measured on the surface of the top coating layer is preferably 10 ¹² Ω or less, more preferably 10 ⁴ Ω to 10 ¹² Ω, further preferably 10 ⁴ Ω to 10 ¹¹ Ω, and particularly preferably is 5×10 ⁴ Ω to 10 ¹⁰ Ω, most preferably 10 ⁴ Ω to 10 ⁹ Ω. An adhesive film exhibiting such a surface resistivity can be suitably used as an adhesive film used in the processing or conveyance process of items that do not like static electricity, such as liquid crystal cells or semiconductor devices. The value of surface resistivity can be calculated from the value of surface resistance measured in an atmosphere of 23°C and 50% RH using a commercially available insulation resistance measuring device.

The friction coefficient of the top coating layer is preferably 0.4 or less. By using a top coating layer with such a low coefficient of friction, when a load (such as a load that causes scratches) is applied to the top coating layer, the load is transferred along the surface of the top coating layer, thereby reducing the frictional force caused by the load. . This makes it difficult for cohesive failure of the top coating layer (damage mode in which the top coating layer is destroyed internally) or interfacial failure (damage mode in which the top coating layer peels off from the back surface of the substrate) to occur. Therefore, it is possible to further prevent scratches from occurring on the adhesive film. The lower limit of the friction coefficient is preferably 0.1 or more, and more preferably 0.15 or more, taking into consideration the balance with other characteristics (e.g., appearance quality, durability, etc.). As the friction coefficient, for example, a value obtained by rubbing the surface of the top coating layer with a vertical load of 40 mN under a measurement environment of 23°C and 50% RH can be adopted. The amount of lubricant used can be set so that a desirable coefficient of friction is achieved. To adjust the friction coefficient, it is also effective to increase the crosslinking density of the top coating layer, for example, by adding a crosslinking agent or adjusting film formation conditions.

The adhesive film preferably has a property that allows its back side (the surface of the top coating layer) to be easily printed with oil-based ink (for example, using an oil-based marking pen). In such an adhesive film, the identification number, etc. of the adherend to be protected is written on the adhesive film in the process of processing or transporting the adherend (for example, an optical component) while the adhesive film is affixed. So it is suitable for display. Therefore, a surface protective film that not only has good appearance but also has excellent durability is desirable. For example, it is desirable that the solvent be alcohol-based and have high print resistance for a type of oil-based ink containing a pigment. Additionally, it is desirable for the printed ink to be difficult to remove due to friction or electrodeposition (i.e., to have excellent printing adhesion). The adhesive film preferably has solvent resistance to a degree that does not cause a noticeable change in appearance even if the print is wiped off with alcohol (for example, ethyl alcohol) when correcting or erasing the print.

Since the top coating layer preferably contains wax ester as a lubricant, a new peeling treatment (for example, a treatment of applying any suitable peeling treatment agent such as a silicone-based peeling agent or a long-chain alkyl-based peeling agent) to the surface of the top coating layer and drying it. Even in an embodiment in which ) is not implemented, sufficient slipperiness (for example, the desirable coefficient of friction described above) can be achieved. This mode in which no new peeling treatment is applied to the surface of the top coating layer is preferable in that whitening caused by the peeling treatment agent (for example, whitening due to storage under heating and humidifying conditions) can be prevented in advance. do. Additionally, it is advantageous in terms of solvent resistance.

The adhesive film may be added to the base material, adhesive layer, and top coat layer, and may also be implemented in an embodiment including other layers. Examples of the arrangement of such “other layers” include between the first side (back) of the substrate and the top coating layer, between the second side (front) of the substrate and the adhesive layer, etc. The layer disposed between the back surface of the substrate and the top coating 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 adhesive layer may be, for example, an undercoat layer (anchor layer), an antistatic layer, etc. that improves anchoring properties of the adhesive layer to the second surface. The adhesive film may be configured such that 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 on the antistatic layer.

≪≪Foldable devices and rollable devices≫≫

The adhesive film of the present invention has excellent flexibility and transparency, so 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 that can be rounded) having a movable bending portion. device). Since the adhesive film of the present invention is particularly excellent in flexibility and transparency, it can be suitably used in foldable devices (devices that can be folded) or rollable devices (devices that can be rolled), which have been more difficult to apply so far.

The foldable device of the present invention includes the adhesive film of the present invention. The foldable device of the present invention may include any suitable other members as long as it is provided with the adhesive film of the present invention.

The rollable device of the present invention is provided with the adhesive film of the present invention. The rollable device of the present invention may include any suitable other members as long as it is provided with the adhesive film of the present invention.

1 is a schematic cross-sectional view showing one embodiment of the foldable device of the present invention as a representative example of one use form of the adhesive film of the present invention. In Figure 1, the foldable device 1000 of the present invention includes a cover film 10, an adhesive layer 20, a polarizer 30, an adhesive layer 40, a touch sensor 50, and an adhesive layer 60. , OLED (70), and the adhesive film (100) of the present invention. In FIG. 1, the adhesive film 100 of the present invention is composed of an adhesive layer 80 and a base material layer 90. The adhesive layer 20, the adhesive layer 40, and the adhesive layer 60 are. It may be an adhesive layer containing an adhesive of the same composition as the adhesive layer 80 constituting the adhesive film 100 of the present invention, or may be an adhesive layer containing an adhesive of a different composition.

The adhesive film of the present invention has excellent flexibility and transparency, so 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 that can be rounded) has a movable bending portion. It can be suitably provided on the back (the side opposite to the display surface) of the device. Figure 1 is a diagram provided on the back (the side opposite to the display surface) of a foldable device (a device that can be folded).

Example

Below, the present invention will be described in more detail through examples and comparative examples. However, the present invention is not limited to these at all. In addition, in the following description, “part” and “%” are based on weight, unless otherwise specified.

<tanδ>

Measurements were made with a viscoelasticity measuring device "RSA-G2" (manufactured by TA Instruments Japan Co., Ltd.) in tensile mode, with a sample size of 5 mm in width x 15 mm in distance, and an axial force of 100 g. In the strain sweep (oscillation amplitude) mode, the frequency was set to 1 Hz, the measurement temperature was 90°C, the immersion time was 60 seconds, and the strain measurement range was set from 0.01% to 1.0%, and the strain in the range was measured. The values of tan δ at each strain were graphed, and tan δ of 0.1% strain and 0.7% strain were obtained from the graph. Regarding the thickness, the rigidity of the substrate is large for both the storage modulus and the loss modulus for the adhesive film, and the influence of the adhesive is negligible. Therefore, the measurement was performed by inputting only the thickness of the substrate excluding the thickness of the adhesive.

tanδ was obtained by the following equation.

tanδ=loss modulus/storage modulus

<Bending test>

As shown in FIG. 2, the adhesive film in a flat state is fixed in such a way that it is sandwiched between the silicone-treated side of a silicone-treated separator, with the adhesive layer side facing outward and the adhesive film bent at 6Φ, and incubated at 90°C for 48 hours. maintained. Afterwards, the bend was released and left to stand at 23°C and 50% RH for 24 hours, and then the angle of the bent film was measured. The case where it was completely restored to its original state was set at 180 degrees, and the case where the bent state at the initial fixation was maintained was set at 0 degrees.

<Peeling evaluation>

The adhesive film was bonded to a PET film (Toray S10) with a thickness of 50 ㎛, bent so that the adhesive film was on the inside as shown in Figure 3, held at 90°C for 48 hours, and then fixed. After release, the peeling of the adhesive film from the PET film was visually observed. Evaluation was performed according to the following standards.

○: No peeling from the PET film was observed.

×: Peeling from the PET film is visible.

<Haze, measurement of total light transmittance>

Haze meter HM-150 (manufactured by Murakami Shikisai Kijutsu Kenkyujo Co., Ltd.) was used, in accordance with JIS-K-7136, haze (%) = (Td/Tt) x 100 (Td: diffuse transmittance, Tt: It was calculated by total light transmittance). In addition, the total light transmittance was measured based on JIS-K-7316.

<Young’s modulus>

A sample piece was cut into a rectangle with a width of 10 mm, and the rectangular sample piece was stretched in the long side direction at a distance between chucks of 100 mm using a universal tensile compression tester (Tensilon) under a temperature environment of 25°C and measured, and the obtained S-S (Strain -Strength) Young’s modulus was obtained rather than the curve. As measurement conditions, the tensile speed was 200 mm/min and the chuck spacing was 50 mm. The method of calculating Young's modulus from the S-S curve was to create a graph of the S-S curve, draw a tangent line (linear equation) on the graph in the range of displacement 1 mm to 2 mm, and obtain it from the slope of the tangent line.

<Adhesion>

The adhesive film was cut to a width of 25 mm and a length of 150 mm, and was used as a sample for evaluation. In an atmosphere of a temperature of 23°C and a humidity of 50% RH, the surface of the adhesive layer of the evaluation sample was affixed to a glass plate (Matsunami Glass Kogyo Co., Ltd., product name: Micro Slide Glass S) with one reciprocation of a 2.0 kg roller. . After curing for 30 minutes in an atmosphere of 23°C and 50% RH humidity, peeling was performed using a universal tensile tester (manufactured by Minebea Corporation, product name: TCM-1kNB) at a peeling angle of 180 degrees and a tensile speed of 300 mm/min. And the adhesive force was measured.

<Applicability>

Count the number of circular irregularities in the applied top coating layer (containing antistatic layer). Two sheets were written in A4 size and the average number was calculated.

2 or less were judged to be good, and 3 or more were judged to be defective. The circular non-uniform part was a part where the thickness of the top coating layer was becoming thinner and was a defect in the external appearance, and the part where the antistatic agent was thrown away and could not be applied at all was referred to as “cratering.”

<Surface resistance value (for Example 8)>

In Example 8, the layer on which the antistatic treatment layer was formed was measured at a voltage of 10 V using a volume resistance meter Model 152-1 152P-2P probe (manufactured by Trek Japan Co., Ltd.).

<Surface resistivity (for Examples 9 to 17 and Comparative Examples 6 to 9)

In Examples 9 to 17 and Comparative Examples 6 to 9, a URS probe was brought into contact with the surface of the adhesive film not provided with the adhesive layer using a resistivity meter (“Hiresta UP MCP-HT450 type” manufactured by Mitsubishi Chemical Analytech). The surface resistivity was measured under the conditions of an applied voltage of 100V and a voltage application time of 10 seconds.

[Preparation Example 1]: Preparation of adhesive composition A

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

Next, to the solution of the acrylic polymer (a1), an isocyanate-based crosslinking agent (brand name “Takenate D110N”, manufactured by Mitsui Chemicals Co., Ltd.) was added in an amount of 1 part by weight in terms of solid content based on 100 parts by weight of acrylic polymer (a) (solid content). It was added as much as possible to prepare adhesive composition A.

[Preparation Example 2]: Preparation of adhesive composition B

In a four-neck flask equipped with a stirring blade, thermometer, nitrogen gas introduction tube, and condenser, 96.2 parts by weight of 2-ethylhexyl acrylate (2EHA), 3.8 parts by weight of hydroxyethyl acrylate (HEA), and 2,2 as a polymerization initiator. '-Add 0.2 parts by weight of azobisisobutyronitrile and 150 parts by weight of ethyl acetate, introduce nitrogen gas while gently stirring, and perform a polymerization reaction for 6 hours while maintaining the liquid temperature in the flask at around 60°C to form an acrylic polymer ( A solution (40% by weight) of b) was prepared. The weight average molecular weight of the acrylic polymer (b) was 540,000.

Next, the solution (40% by weight) of the acrylic polymer (b) was diluted to 25% by weight with ethyl acetate, and hexamethylene diisocyanate, a trifunctional isocyanate compound, was added to 400 parts by weight of this solution (100 parts by weight of solid content) as a crosslinking agent. 4 parts by weight of isocyanurate (Coronate HX, manufactured by Tosoh Corporation) (solid content: 4 parts by weight), dioctyltin dilaurate as a crosslinking catalyst (Envirizer O-1, manufactured by Tokyo Fine Chemical Company, 1% by weight ethyl acetate solution) 2 parts by weight (solid content: 0.02 parts by weight) and 3 parts by weight of acetylacetone were added and mixed and stirred to prepare adhesive composition B.

[Example 1]

A commercially available release liner (“Diafoil MRF-38”, manufactured by Mitsubishi Juicy Co., Ltd.) was prepared. The adhesive composition A was applied to one side (release surface) of the release liner so that the thickness after drying was 25 μm, and dried at 130°C for 3 minutes. In this way, a 25-μm-thick adhesive layer made of the acrylic adhesive A corresponding to the adhesive composition A was formed on the release surface of the release liner.

As a base material layer, a polyimide-based base material (brand name “Kapton”, manufactured by Toray DuPont Co., Ltd.) with a thickness of 50 μm was prepared. The adhesive layer formed on the release liner was bonded to one side of this base material layer. The release liner was left on the adhesive layer as is and used to protect the surface of the adhesive layer (adhesive layer surface). 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 adhesive film (1) was obtained.

The results are shown in Table 1.

[Example 2]

An adhesive film (2) was obtained in the same manner as in Example 1, except that a polyimide-based substrate with a thickness of 50 μm (trade name “Upilex-50S”, manufactured by Ube Kosan Co., Ltd.) was used as the substrate layer.

The results are shown in Table 1.

[Example 3]

An adhesive film (3) was obtained in the same manner as in Example 1, except that a 50-μm-thick polyimide-based substrate (product name “Pixio BP”, Kaneka Co., Ltd.) was used as the substrate layer.

The results are shown in Table 1.

[Example 4]

An adhesive film (4) 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 1.

[Example 5]

Example 1, except that a polyetheretherketone (PEEK)-based substrate with a thickness of 50 μm (product name “Shin-Etsu Sepla Film”, non-stretched high-crystal, manufactured by Shin-Etsu Polymer Co., Ltd.) was used as the substrate layer. In the same manner as above, an adhesive film (5) was obtained.

The results are shown in Table 1.

[Example 6]

An adhesive film (6) was obtained in the same manner as in Example 1, except that a polyimide-based substrate with a thickness of 50 μm (trade name “Neopullim S100”, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was used as the substrate layer.

The results are shown in Table 1.

[Example 7]

An adhesive film (7) was obtained in the same manner as in Example 1, except that a polyetheretherketone (PEEK)-based substrate (brand name "Xpeak", manufactured by Kurabo Co., Ltd.) with a thickness of 25 μm was used as the substrate layer.

The results are shown in Table 1.

[Comparative Example 1]

An adhesive film (C1) was obtained in the same manner as in Example 1, except that a 25-μm-thick polyester-based substrate (brand name “Lumiror S10”, Toray Co., Ltd.) was used as the substrate layer.

The results are shown in Table 1.

[Comparative Example 2]

An adhesive film (C2) was obtained in the same manner as in Example 1, except that a 50-μm-thick polyester-based substrate (brand name “Lumirror S10”, Toray Co., Ltd.) was used as the substrate layer.

The results are shown in Table 1.

[Comparative Example 3]

The same procedure as in Example 1 was carried out except that adhesive composition B was used instead of adhesive composition A and a polyester base material with a thickness of 50 μm (product name “Lumiror S10”, Toray Co., Ltd.) was used as the base layer, and an adhesive film ( C3) was obtained.

The results are shown in Table 1.

[Comparative Example 4]

An adhesive film (C4) was obtained in the same manner as in Example 6, except that adhesive composition B was used instead of adhesive composition A.

The results are shown in Table 1.

[Comparative Example 5]

An adhesive film (C5) was obtained in the same manner as in Example 7, except that adhesive composition B was used instead of adhesive composition A.

The results are shown in Table 1.

[Production Example 3]: Production of antistatic treated polyimide film A

An antistatic agent solution was prepared by diluting 10 parts by weight of an antistatic agent (Micro Solver RMd-142, manufactured by Solvex Co., Ltd., mainly containing tin oxide and polyester resin) with a mixed solvent consisting of 30 parts by weight of water and 70 parts by weight of methanol. The obtained antistatic agent solution was applied using a Meyer bar on a polyimide-based substrate with a thickness of 50 μm (product name “Kapton”, manufactured by Toray DuPont Co., Ltd.) using a Meyer bar, and the solvent was removed by drying at 130°C for 1 minute. , an antistatic layer (thickness: 0.2 μm) was formed, and antistatic treated polyimide film A was produced.

[Example 8]

An adhesive film (8) was obtained in the same manner as in Example 1, except that antistatic treated polyimide film A was used as the base material. The surface resistance value was 5×10 ⁶ Ω.

[Manufacture Example 4]: Production of top coating layer forming polyimide film B

<Preparation of coating material B>

A dispersion containing 25% by weight of polyester resin (binder) as a binder (manufactured by Toyobo Co., Ltd., brand name “Binarol MD-1480” (aqueous dispersion of saturated copolyester resin); hereinafter also referred to as “binder dispersion”. .) was prepared.

Additionally, as a lubricant, an aqueous dispersion (hereinafter also referred to as “lubricant dispersion”) of carnauba wax (manufactured by Nippon Wax, brand name “Refined Carnauba Wax No. 2 Powder”) was prepared.

Additionally, as a conductive polymer, an aqueous solution containing 0.5% by weight of poly(3,4-dioxythiophene) (PEDOT) and 0.8% by weight of polystyrene sulfonate (number average molecular weight: 150,000) (PSS) (manufactured by H.C.Stark, brand name) “Baytron P”; hereinafter also referred to as “conductive polymer aqueous solution”) was prepared.

In a mixed solvent of water and ethanol (weight ratio 50:50), 100 parts by weight of the binder dispersion as a solid content, 30 parts by weight as a solid content of the above-mentioned lubricant dispersion, and 50 parts by weight of the conductive polymer aqueous solution as a solid content. 7 parts by weight of a melamine-based crosslinking agent were added, stirred for about 20 minutes, and thoroughly mixed. In this way, coating material B containing about 0.15% by weight of NV was prepared.

<Production of top coating layer forming polyimide film B>

The above-mentioned coating material B was applied and adhered using a bar coater onto a polyimide-based substrate with a thickness of 50 μm (trade name “Kapton”, manufactured by Toray DuPont Co., Ltd.) and dried by heating at 130°C for 2 minutes. In this way, a base material (top coat layer forming polyimide film B) having a transparent top coating layer with a thickness of 10 nm on one side of the polyimide base material was produced.

[Manufacture Example 5]: Production of top coating layer forming polyimide film C

<Preparation of coating material C>

An aqueous solution containing 25% by weight of a polyester urethane resin consisting of 25 mol% ethylene glycol, 25 mol% neopentyl glycol, 30 mol% terephthalic acid, 10 mol% adipic acid, and 10 mol% tolylene diisocyanate as a binder; (hereinafter also referred to as “binder dispersion”) was prepared.

Additionally, as a lubricant, an aqueous dispersion (hereinafter also referred to as “lubricant dispersion”) of carnauba wax (manufactured by Nippon Wax, brand name “Refined Carnauba Wax No. 2 Powder”) was prepared.

Additionally, as a conductive polymer, an aqueous solution containing 0.5% by weight of poly(3,4-dioxythiophene) (PEDOT) and 0.8% by weight of polystyrene sulfonate (number average molecular weight: 150,000) (PSS) (manufactured by H.C.Stark, Inc.) (trade name “Baytron P”; hereinafter also referred to as “conductive polymer aqueous solution”) was prepared.

Additionally, an aqueous solution containing 10% by weight of polyethylene glycol (PEG) alkyl ether and 10% by weight of polyvinyl alcohol was prepared as a dispersant.

In a mixed solvent of water and ethanol (weight ratio 50:50), 40 parts by weight of the binder dispersion in solids ratio, 5 parts by weight of the lubricant dispersion in solids, and 8 parts by weight of the conductive polymer aqueous solution in solids. , 40 parts by weight of the dispersant and 7 parts by weight of the melamine-based crosslinking agent were added, stirred for about 20 minutes, and thoroughly mixed. In this way, coating material C with NV of about 0.30% by weight was prepared.

<Production of top coating layer forming polyimide film C>

The coating material C was applied and adhered using a bar coater onto a polyimide-based substrate with a thickness of 50 μm (trade name “Kapton”, manufactured by Toray DuPont Co., Ltd.), and dried by heating at 130°C for 2 minutes. In this way, a base material (top coat layer forming polyimide film C) having a transparent top coating layer with a thickness of 50 nm on one side of the polyimide base material was produced.

[Example 9]

An adhesive film (9) was obtained in the same manner as in Example 1 except that polyimide film B with top coating layer was used as the base material.

The results are shown in Table 2.

[Example 10]

An adhesive film (10) was obtained in the same manner as in Example 2, except that polyimide film B with top coating layer was used as the base material.

The results are shown in Table 2.

[Example 11]

An adhesive film (11) was obtained in the same manner as in Example 4, except that polyimide film B with top coating layer was used as the base material.

The results are shown in Table 2.

[Example 12]

An adhesive film (12) was obtained in the same manner as in Example 7, except that polyimide film B with top coating layer was used as the base material.

The results are shown in Table 2.

[Example 13]

An adhesive film (13) was obtained in the same manner as in Example 1 except that polyimide film C with top coating layer was used as the base material.

The results are shown in Table 2.

[Example 14]

An adhesive film (14) was obtained in the same manner as in Example 2, except that polyimide film C with top coating layer was used as the base material.

The results are shown in Table 2.

[Example 15]

An adhesive film (15) was obtained in the same manner as in Example 3, except that polyimide film C with top coating layer was used as the base material.

The results are shown in Table 2.

[Example 16]

An adhesive film (16) was obtained in the same manner as in Example 4, except that polyimide film C with top coating layer was used as the base material.

The results are shown in Table 2.

[Example 17]

An adhesive film (17) was obtained in the same manner as in Example 7, except that polyimide film C with top coating layer was used as the base material.

The results are shown in Table 2.

[Comparative Example 6]

An adhesive film (C6) was obtained in the same manner as in Comparative Example 1 except that polyimide film B with top coating layer was used as the base material.

The results are shown in Table 2.

[Comparative Example 7]

An adhesive film (C7) was obtained in the same manner as in Comparative Example 2 except that polyimide film B with top coating layer was used as the base material.

The results are shown in Table 2.

[Comparative Example 8]

An adhesive film (C8) was obtained in the same manner as in Comparative Example 1 except that polyimide film C with a top coating layer was used as the base material.

The results are shown in Table 2.

[Comparative Example 9]

An adhesive film (C9) was obtained in the same manner as in Comparative Example 2, except that polyimide film C with top coating layer was used as the base material.

The results are shown in Table 2.

The adhesive film of the present invention has excellent flexibility and transparency, so 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 that can be rounded) has a movable bending portion. device).

1000: Foldable device
100: Adhesive 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 bong
2: Siliconized separator
3: Adhesive layer
4: fixed glass
5: PET film

Claims (20)

It is an adhesive film having a base layer and an adhesive layer,
The material of the base layer is at least one selected from polyimide and polyetheretherketone,
The adhesive force of the adhesive layer to the glass plate at 23°C, a tensile speed of 300 mm/min, and 180 degree peel is 1 N/25 mm or more,
tanδ (0.7%) at 0.7% strain measured in the tensile mode of the viscoelasticity measuring device is 0.1 or less,
Adhesive film. It is an adhesive film having a base layer and an adhesive layer,
The material of the base layer is at least one selected from polyimide and polyetheretherketone,
The adhesive force of the adhesive layer to the glass plate at 23°C, a tensile speed of 300 mm/min, and 180 degree peel is 1 N/25 mm or more,
The difference (tanδ (0.7%) - tanδ (0.1%)) between tanδ (0.7%) at a strain of 0.7% and tanδ (0.1%) at a strain of 0.1% measured in the tensile mode of a viscoelasticity measuring device is 0.05 or less. ,
Adhesive film. The method according to claim 1 or 2, wherein after bending to 6Φ and holding at 90°C for 48 hours, the bending is released, and the bending angle after being left at 23°C and 50% RH for 24 hours is 60 to 180 degrees. Adhesive film. The adhesive film according to claim 1 or 2, which has a top coating layer on a side of the base material layer opposite to the side having the adhesive layer. The adhesive film according to claim 4, wherein the top coating layer contains a binder containing at least one selected from polyester resin and urethane resin. The adhesive film according to claim 5, wherein the binder contains a urethane-based resin. The adhesive film according to claim 4, wherein the top coating layer contains an antistatic component. The adhesive film according to claim 1 or 2, wherein the base layer has a Young's modulus at 23°C of 6.0×10 ⁷ Pa or more. The substrate according to claim 1 or 2, wherein the substrate layer has a top coating layer on a side opposite to the side having the adhesive layer, and the top coating layer contains a binder containing a urethane resin and an antistatic component, and the substrate layer has a top coating layer. An adhesive film, wherein the material of the layer is at least one selected from polyimide and polyetheretherketone. The adhesive film according to claim 1 or 2, wherein the total light transmittance is 20% or more. The adhesive film according to claim 1 or 2, wherein the adhesive film has a haze of 15% or less. The adhesive film according to claim 1 or 2, wherein the adhesive layer contains an acrylic adhesive. The adhesive film according to claim 1 or 2, which is attached to a foldable member. The adhesive film according to claim 13, wherein the foldable member is an OLED. The adhesive film according to claim 1 or 2, which is attached to a rollable member. The adhesive film according to claim 15, wherein the rollable member is an OLED. A foldable device comprising the adhesive film according to claim 1 or 2. A rollable device comprising the adhesive film according to claim 1 or 2. delete delete

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