Adhesive film

Abstract

The present application relates to an adhesive film having, in order, an adhesive layer containing an adhesive resin having an elastic modulus of 100 MPa or less, a substrate layer which is a thermoplastic resin film, and a sliding layer containing a polyethylene-based resin and having a thickness of 8 μm or less, wherein the absolute value of the difference between the elastic modulus E MD in the flow direction of the adhesive film and the elastic modulus E TD in the perpendicular direction is 500 MPa or more.

Description

Technical Field

[0001] This invention relates to adhesive films. Background Technology

[0002] As a means of removing hair, dust, and debris attached to objects such as clothing, furniture, interior materials, and daily necessities, adhesive cleaners using adhesive films are known.

[0003] In the IC chip manufacturing process of electronic devices, adhesive cleaners can also be used as a means to remove fine debris generated from the IC chip surface due to cutting, grinding and other processing.

[0004] Adhesive cleaners typically have an adhesive film wound with the adhesive layer facing outwards. The adhesive film has a substrate and an adhesive layer formed on one side of the substrate. By pressing the adhesive cleaner against the object and rotating it, dust and other contaminants are transferred to the adhesive layer, thereby enabling cleaning. When the adhesive layer surface becomes covered with dust, it is peeled off and cut along with the adhesive film, exposing a new adhesive surface for reuse.

[0005] Here, the other side of the substrate and the adhesive layer need to adhere tightly without peeling during storage and use of the cleaner. When cutting the adhesive film after use, it needs to be peelable without damaging the adhesive properties of the adhesive layer. To facilitate peeling the other side of the substrate from the adhesive layer, a layer containing a release agent (lubricant) such as silicone or wax was attempted on the other side of the substrate. However, the release agent being transferred to the adhesive layer side reduces adhesion or may contaminate the IC chip; therefore, an adhesive cleaner that does not use a release agent is required.

[0006] Patent Document 1 describes an adhesive cleaner that uses a two-component polyurethane adhesive as the adhesive component and a polyethylene film as the material for forming the release surface, thereby eliminating the need for a release agent.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2002-307554 Summary of the Invention

[0010] The technical problem that the invention aims to solve

[0011] However, for the adhesive cleaner described in Patent Document 1, the adhesive film is not cut sufficiently, making it difficult to cut in a straight line by hand. A mechanical cutting process is required, or a cutting slit needs to be added to the adhesive film, which may increase costs.

[0012] The purpose of this invention is to provide an adhesive film that, in addition to having high adhesive and peel properties, also has excellent cutability.

[0013] Technical solutions for solving technical problems

[0014] In order to solve the above-mentioned problems, the inventors conducted in-depth research and found that by using a film containing polyethylene resin of a specific thickness as the sliding layer, the orientation of the adhesive film can be within a specific range, thus solving the above-mentioned problems.

[0015] That is, the present invention relates to adhesive films, etc.

[0016] [1] An adhesive film, comprising, in sequence, an adhesive layer, a substrate layer, and a sliding layer, wherein,

[0017] The adhesive layer contains an adhesive resin with an elastic modulus of less than 100 MPa.

[0018] The substrate layer is a thermoplastic resin film.

[0019] The sliding layer comprises polyethylene resin and has a thickness of less than 8 μm.

[0020] The elastic modulus E in the flow direction of the adhesive film MD Elastic modulus E in the vertical direction TD The absolute value of the difference, |ΔE|, is above 500 MPa.

[0021] [2] According to the adhesive film of [1], the surface roughness of the sliding layer is 0.05 μm or more and 5 μm or less.

[0022] [3] The adhesive film according to [1] or [2], wherein the substrate layer comprises a polypropylene resin and a filler.

[0023] [4] An adhesive film according to any one of [1] to [3], wherein the substrate layer is porous.

[0024] [5] The adhesive film according to any one of [1] to [4], wherein a coating layer is further provided between the adhesive layer and the substrate layer.

[0025] The coating layer contains one or more selected from polyurethane resins, olefin copolymers, styrene resins, and ethyleneimine resins.

[0026] [6] An adhesive film according to any one of [1] to [5], wherein the sliding layer is a uniaxially stretched resin film.

[0027] [7] An adhesive film laminate, wherein the adhesive film described in any one of [1] to [6] is laminated in such a way that the adhesive layer contacts the sliding layer.

[0028] [8] A laminated film having a substrate layer and a sliding layer sequentially.

[0029] The substrate layer is a thermoplastic resin film.

[0030] The sliding layer comprises polyethylene resin and has a thickness of less than 8 μm.

[0031] The elastic modulus E in the flow direction of the laminated film MD Elastic modulus E in the vertical direction TD The absolute value of the difference, |ΔE|, is above 500 MPa.

[0032] Invention Effects

[0033] According to the present invention, an adhesive film can be provided that, in addition to high adhesive and peel properties, also has excellent cutability. Attached Figure Description

[0034] Figure 1 This is a cross-sectional view showing an example of an adhesive film. Detailed Implementation

[0035] The adhesive film of the present invention will now be described in detail. The following is a representative example of the present invention, and the invention is not limited thereto.

[0036] <Adhesive film>

[0037] Figure 1 An example of the adhesive film of the present invention is shown. For example... Figure 1 As shown, the adhesive film 10 has an adhesive layer 3, a substrate layer 1, and a sliding layer 2 in sequence.

[0038] The adhesive layer 3 contains an adhesive resin with an elastic modulus of 100 MPa or less. This configuration imparts adhesive properties to the film of the present invention.

[0039] The substrate layer 1 is a thermoplastic resin film.

[0040] The sliding layer 2 contains a polyethylene-based resin and has a thickness of 8 μm or less. By containing a polyethylene-based resin, the adhesive film can be given easy-to-peel properties. In addition, by making the sliding layer thin, the cutability of the adhesive film can be well maintained without reducing it.

[0041] Furthermore, the elastic modulus E in the flow direction of the adhesive film 10 MD Elastic modulus E in the vertical direction TDThe absolute value of the difference, |ΔE|, is over 500 MPa. The adhesive film has a specific orientation, which results in improved tearability, thus allowing for the production of adhesive films with excellent straight-line cutting properties that can be torn and cut even with manual force.

[0042] The flow direction refers to the direction of resin flow (machine direction), and the perpendicular direction refers to the direction perpendicular to the flow direction (transverse direction). When there is a difference in elastic modulus |ΔE| between different directions, the adhesive film easily achieves linear tear resistance. Furthermore, by making the elastic modulus difference |ΔE| greater than 500 MPa, the linear tear resistance of the adhesive film is improved. This is believed to be due to the generation of a tear strength difference between the flow direction and the perpendicular direction, thus preferentially causing failure in the direction with lower tear strength. It should be noted that the elastic modulus of the adhesive film refers to the storage modulus measured using a solid viscoelasticity measuring apparatus (manufactured by TA Instruments Japan Inc.: RSA-III), where the adhesive film is cut into test pieces with a length of 30 mm and a width of 15 mm. The measurement conditions were set as follows: chuck distance 20 mm, measurement frequency 10 Hz, strain 0.1%, heating rate 10 °C / min, tensile mode, and temperature set to 23 °C.

[0043] From the viewpoint of linear shear strength, a larger difference in elastic modulus |ΔE| is better. Linear shear strength becomes good from 500 MPa and above, preferably 1000 MPa and above, and more preferably 2000 MPa and above. On the other hand, from the viewpoint of the tensile strength of the resin, it is generally 4000 MPa and below.

[0044] The direction with the highest elastic modulus can be either the flow direction or the vertical direction, but from the viewpoint of ensuring that the winding direction during manufacturing is the same as the winding direction of the adhesive film product and reducing additional processes, an elastic modulus E in the vertical direction is preferred. TD Elastic modulus E greater than the flow direction MD .

[0045] That is, the following relation is preferred.

[0046] E TD -E MD ≥500 (MPa)

[0047] Furthermore, the elastic modulus of the adhesive film in the cutting direction (tear direction) is preferably 500 MPa or more, more preferably 1000 MPa or more, and particularly preferably 2000 MPa or more. With an elastic modulus difference |ΔE| of 500 MPa or more and a high elastic modulus in the cutting direction, the linear cutability of the adhesive film becomes better. The cutting direction can be either the flow direction or the vertical direction, but from the viewpoint of ensuring that the winding direction during manufacturing is the same as the winding direction of the product, the vertical direction is preferred.

[0048] It should be noted that the specific elastic modulus difference |ΔE| is a characteristic mainly imparted by the orientation of the substrate layer. Therefore, in order to obtain an adhesive film with an elastic modulus difference |ΔE| of a specific value or higher, for example, as described below, a substrate layer having an orientation can be provided.

[0049] Furthermore, the laminated film of the present invention, which sequentially comprises a substrate layer and a sliding layer, also exhibits the same elastic modulus E in the flow direction as the adhesive film laminate. MD Elastic modulus E in the vertical direction TD The absolute value of the difference, |ΔE|, is above 500 MPa.

[0050] The following is an explanation of each layer.

[0051] <Adhesive Layer>

[0052] The adhesive layer contains an adhesive resin and functions to impart adhesion to the film. Here, the elastic modulus of the adhesive resin is 100 MPa or less, preferably 80 MPa or less, and more preferably 50 MPa or less. By setting the elastic modulus within the above range, there is a tendency to further improve adhesion. Furthermore, from the viewpoint of avoiding both strength maintenance and excessive adhesion of the adhesive layer, the elastic modulus is preferably 0.1 MPa or more, and more preferably 0.5 MPa or more. It should be noted that the elastic modulus of the adhesive resin refers to the indentation modulus in the thickness direction of the adhesive layer surface, as measured using a nanoindenter.

[0053] The adhesive resin can be any resin that is somewhat soft, as described above, with an elastic modulus of 100 MPa or less. Examples of such resins include acrylic resins, elastic resins, and ethylene-vinyl acetate copolymers (EVA), with acrylic resins or elastic resins being preferred, and acrylic resins being more preferred. One or more of these resins can be used alone or in combination.

[0054] Examples of acrylic resins include: acrylate copolymers, methacrylate copolymers, and acrylamide-acrylate copolymers.

[0055] As an elastic system resin, there are no particular limitations as long as it is thermoplastic and has rubber-like elasticity at room temperature; various known resins can be used. Specific examples include olefin-based thermoplastic elastomers containing hard-chain segments of polyolefins such as polyethylene and polypropylene, and soft-chain segments of other polyolefins, α-olefins such as 1-butene, or ethylene propylene rubber.

[0056] From the viewpoint of moldability and maintaining adhesion, the thickness of the adhesive layer is preferably 1 μm or more, more preferably 3 μm or more. In addition, from the viewpoint of cost reduction, maintaining straight-cutting properties and maintaining peelability, it is preferably 30 μm or less, more preferably 20 μm or less.

[0057] <Substrate Layer>

[0058] The substrate layer is a thermoplastic resin film, which serves as a support for the adhesive film.

[0059] From the viewpoint that the adhesive film easily satisfies the aforementioned specific elastic modulus difference |ΔE| and thus possesses linear cutting properties, the substrate layer preferably has an orientation. Specifically, the substrate layer preferably has an elastic modulus difference |ΔE| of 500 MPa or more, more preferably 1000 MPa or more, and particularly preferably 2000 MPa or more. On the other hand, from the viewpoint of the tensile strength of the resin, it is typically 4000 MPa or less.

[0060] Furthermore, the elastic modulus of the substrate layer in the cutting direction (tear direction) is preferably 500 MPa or more, more preferably 1000 MPa or more, and particularly preferably 2000 MPa or more. With an elastic modulus difference |ΔE| of 500 MPa or more and a high elastic modulus in the cutting direction, the linear cutability of the substrate layer becomes better. The cutting direction can be either the flow direction or the vertical direction, but from the viewpoint of ensuring that the winding direction during manufacturing is the same as the winding direction of the product, the vertical direction is preferred.

[0061] In order to make the difference in elastic modulus |ΔE| of the substrate layer 500 MPa or more, for example, a stretched resin film in which the substrate layer is stretched at least in the uniaxial direction can be used. It can be stretched in the uniaxial direction or in the biaxial direction, but from the viewpoint of improving the strength, toughness and porosity of the substrate layer, a biaxial stretched resin film is particularly preferred.

[0062] There are no particular limitations on the thermoplastic resin used to form the substrate layer. For example, from the viewpoint of moldability and cost, polyolefin resins are preferred.

[0063] <Polyolefin Resins>

[0064] Specific examples of polyolefin resins include polypropylene resins, polyethylene resins, or polymethyl-1-pentene, with polypropylene resins or polyethylene resins being preferred, and polypropylene resins being even more preferred.

[0065] As for polypropylene-based resins, there are no particular limitations as long as the resin uses propylene as the main monomer. Examples include isotactic polymers or syndiotactic polymers formed by homopolymerization of propylene. Additionally, copolymers of propylene as the main component with α-olefins such as ethylene or 1-butene, i.e., propylene-α-olefin copolymers, can also be used. The copolymer can be a multi-component system with a monomer composition of 2 or 3 or more, or it can be a random copolymer or a block copolymer. Among these, propylene homopolymers are preferred. Furthermore, propylene homopolymers and propylene copolymers can be used together.

[0066] Examples of polyethylene-based resins include those with a density of 0.940 g / cm³. 3 ~0.965g / cm 3 High-density polyethylene with a density of 0.920 g / cm³ 3 ~0.935g / cm 3 Medium-density polyethylene with a density of 0.900 g / cm³ 3 Above and below 0.920 g / cm³ 3 Linear low-density polyethylene, copolymers made primarily of ethylene and copolymerized with α-olefins such as propylene, butene, and hexene, ethylene-cyclic olefin copolymers, or maleic acid modified polyethylene, etc.

[0067] In addition, as a polyolefin resin, graft modifiers can be used as needed to improve the adhesion or moldability of its resin film.

[0068] Grafting modification can be performed using known methods. Specifically, examples of grafted modified products using unsaturated carboxylic acids or their derivatives as grafting monomers can be cited. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, or citraconic acid. Examples of derivatives of the above-mentioned unsaturated carboxylic acids include acid anhydrides, esters, amidates, imides, or metal salts of the above-mentioned unsaturated carboxylic acids.

[0069] Specific grafting monomers include: maleic anhydride, itaconic anhydride, citraconic anhydride, methyl (meth)acrylate, ethyl (meth)acrylate, monoethyl maleate, or monomethyl fumarate, etc.

[0070] The graft monomer can typically be used at 0.005% to 10% by mass relative to the polyolefin resin, preferably 0.01% to 5% by mass.

[0071] The polyolefin resin used as the substrate layer can be one of the above-mentioned resins used alone, or two or more can be used in combination. From the viewpoints of moldability, mechanical strength, or cost reduction, the substrate layer is preferably a resin film of polypropylene resin or polyethylene resin, and more preferably a polypropylene resin. Among these, propylene homopolymer is preferred because it is easy to process as the main raw material of the substrate layer.

[0072] In polypropylene-based resin films, from the viewpoint of film formability, propylene homopolymers and resins with melting points of similar or lower can be used together. Polyethylene-based resins, specifically high-density or low-density polyethylene, are examples of such resins. The amount of polyethylene-based resin incorporated can, for example, be set to 2% to 25% by mass.

[0073] <Packaging>

[0074] The substrate layer may contain fillers. By including fillers, it is easy to form pores within the substrate layer, resulting in a porous substrate layer. This makes it easier to adjust the whiteness or opacity of the film, and also enables the lightweighting of the substrate layer, and even adhesive films. Examples of fillers that can be used include inorganic or organic fillers.

[0075] <<Inorganic Packing>>

[0076] Inorganic fillers, such as calcium carbonate, calcined clay, silica, diatomaceous earth, kaolin, talc, titanium dioxide, barium sulfate, barium titanate, alumina, zeolite, mica, sericite, bentonite, sepiolite, vermiculite, dolomite, wollastonite, or glass fiber, can be used. The average particle size of the inorganic filler, determined by a laser diffractometer, is typically 0.01 μm to 15 μm, preferably 0.1 μm to 5 μm.

[0077] <<Organic Fillers>>

[0078] As the organic filler, it is preferable to select a resin of a different type than the polyolefin resin that is the main component of the substrate layer. Examples of such organic fillers include polymers such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, nylon-6, nylon-6,6, cyclic polyolefins, polystyrene, or polymethacrylate, which have a higher melting point (e.g., 170°C to 300°C) or a higher glass transition temperature (e.g., 170°C to 280°C) than the polyolefin resin, and are immiscible.

[0079] As packing materials, the aforementioned inorganic and organic packing materials can be used individually or in combination.

[0080] The filler content in the substrate layer (the total amount when inorganic and organic fillers are used together) is preferably 10% by mass or more, more preferably 15% by mass or more, from the viewpoint of making it easier to visually identify dirt on the cleaning roller by improving whiteness. On the other hand, from the viewpoint of suppressing paper dust, it is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 35% by mass or less.

[0081] <Other Ingredients>

[0082] The substrate layer may, as needed, contain heat stabilizers (antioxidants), light stabilizers, dispersants, lubricants, or nucleating agents, without hindering the effects of the present invention.

[0083] As heat stabilizers, such as hindered phenolic antioxidants, phosphorus antioxidants, or amine antioxidants, they can typically be used in the range of 0.001% to 1% by mass.

[0084] As light stabilizers, such as hindered amine light stabilizers, benzotriazole light stabilizers, or benzophenone light stabilizers, they can generally be used in the range of 0.001% by mass to 1% by mass.

[0085] Examples of dispersants or lubricants include: silane coupling agents, higher fatty acids such as oleic acid and stearic acid, metal soaps, polyacrylic acid, polymethacrylic acid, or their salts. These dispersants or lubricants, for example for the purpose of dispersing fillers, are typically used in the range of 0.01% to 4% by mass.

[0086] <Structure of the substrate layer>

[0087] The substrate layer can be a single layer or a multi-layer structure with two or more layers. By multi-layering, various functions can be imparted to the substrate layer, such as mechanical properties, writeability, abrasion resistance, or adaptability for secondary processing.

[0088] Furthermore, from the viewpoint of strength and toughness, the thickness of the substrate layer is preferably 10 μm or more, more preferably 30 μm or more, and even more preferably 50 μm or more. On the other hand, from the viewpoint of linear cutting performance and the number of rolls when rolled into a roll, it is preferably 500 μm or less, more preferably 200 μm or less, and even more preferably 100 μm or less.

[0089] <Stretch film>

[0090] From the viewpoint that the aforementioned difference in elastic modulus |ΔE| easily leads to linear cutting properties, the substrate layer is preferably a uniaxially stretched film. On the other hand, when the substrate layer contains filler, from the viewpoint that a larger number of stretching axes can lead to lighter weight and whiter appearance due to porosity, a biaxially stretched film is preferred. However, if biaxial stretching is performed, the aforementioned difference in elastic modulus |ΔE| generated in uniaxial stretching is reduced, which has the potential to impair linear cutting properties. Therefore, when performing biaxial stretching, it is preferable to do so to a degree that does not impair linear cutting properties.

[0091] When the substrate layer has a multi-layer structure, the number of tensile axes in each layer can be the same or different. By combining layers with different numbers of tensile axes, it is possible to design a substrate layer that combines the advantages of uniaxial and biaxial tensile structures. Examples of tensile axes for each layer include: uniaxial / uniaxial, uniaxial / biaxial, biaxial / uniaxial, uniaxial / uniaxial / biaxial, uniaxial / biaxial / uniaxial, biaxial / uniaxial / uniaxial, uniaxial / uniaxial / uniaxial, biaxial / biaxial / uniaxial, or biaxial / biaxial / biaxial.

[0092] <Porosity>

[0093] From the viewpoint of weight reduction or improved whiteness, the porosity of the substrate layer is preferably greater than 0%, and more preferably 50% or less, and even more preferably 40% or less. The porosity can be determined by the ratio of the area occupied by pores in a certain region of the membrane cross-section observed using an electron microscope.

[0094] <Sliding Layer>

[0095] The sliding layer is formed on the other side of the substrate. For the sliding layer, it is required to be tightly bonded to the adhesive layer when the adhesive film is laminated, and to be able to be peeled off without damaging the adhesive properties of the adhesive layer when the adhesive film is peeled off, that is, to balance peel resistance and easy peeling.

[0096] From the viewpoint of taking into account the aforementioned characteristics, the sliding layer comprises a polyethylene-based resin.

[0097] By incorporating a polyethylene-based resin into the sliding layer, sliding properties are improved, and the content of lubricant (release agent) can be suppressed, thus enabling easy peeling without compromising the adhesive properties of the bonding layer. Therefore, even with reduced lubricant dosage, a sliding layer with excellent peelability can be obtained.

[0098] In addition, by thinning the film to less than 8 μm, the strength of the sliding layer is reduced without compromising the cutability of the substrate layer, which is preferable.

[0099] Examples of polyethylene-based resins include the polyethylene-based resins used in the aforementioned substrate layer. Low-density polyethylene is preferred.

[0100] Furthermore, as a polyethylene-based resin, graft-modified materials can be used as needed to improve the adhesion or moldability of the resin film. The grafting modification method and specific grafting monomers are the same as those illustrated in the description of the polyolefin-based resin in the substrate layer.

[0101] The sliding layer preferably contains polyethylene-based resin as a main component. Here, "containing as a main component" means that the content of polyethylene-based resin in the sliding layer is 50% by mass or more. By making polyethylene-based resin the main component of the sliding layer, the peelability becomes suitable.

[0102] It should be noted that the sliding layer may contain other resins, such as polypropylene resins, without hindering the effects of the present invention.

[0103] The surface roughness of the sliding layer is preferably 0.05 μm or more, more preferably 0.1 μm or more, and even more preferably 0.5 μm or more. On the other hand, it is preferably 5 μm or less, more preferably 2 μm or less. If the surface roughness is at or above the lower limit mentioned above, the contact area between the sliding layer and the adhesive layer is reduced during the lamination of the adhesive film, and the peelability is improved. On the other hand, if the surface roughness is at or below the upper limit mentioned above, it is possible to prevent the surface roughness shape of the sliding layer from being transferred to the adhesive layer, thereby reducing the adhesive force. It should be noted that the surface roughness is based on the three-dimensional center surface average roughness (SRa) of JIS-B-0601:2001.

[0104] To produce a sliding layer with the specific surface roughness mentioned above, for example, embossing the surface of the sliding layer or including fillers in the sliding layer can be used individually or in combination.

[0105] The shape of the embossing process is not particularly limited, but it is preferable to perform the process in a manner that achieves the desired surface roughness. Furthermore, known methods can be used for the embossing process.

[0106] As fillers that can be contained in the sliding layer, examples include inorganic fillers or organic fillers, and specific examples of inorganic and organic fillers are the same as those in the substrate layer described above. It should be noted that by incorporating fillers in a layer further inside than the sliding layer, rather than incorporating fillers in the sliding layer, the surface of the sliding layer can also be indirectly roughened.

[0107] As packing materials, the aforementioned inorganic and organic packing materials can be used individually or in combination.

[0108] The filler content in the sliding layer (which is the total amount when inorganic and organic fillers are used together) is preferably 1% to 20% by mass, more preferably 5% to 10% by mass.

[0109] <Other Ingredients>

[0110] The sliding layer is the same as the substrate layer, and may further contain heat stabilizers (antioxidants), light stabilizers, dispersants, lubricants or nucleating agents as needed, without hindering the effect of the present invention.

[0111] <Structure of the sliding layer>

[0112] The sliding layer can be a single-layer structure or a multi-layer structure with two or more layers.

[0113] As described above, from the viewpoint of cutability, the thickness of the sliding layer is 8 μm or less, preferably 5 μm or less. Furthermore, from the viewpoint of preventing exposure of the substrate layer, it is preferably 0.1 μm or more, and more preferably 1 μm or more.

[0114] <Stretch film>

[0115] Polyethylene resin, the main component of the sliding layer, is a resin that is difficult to orient. Therefore, even when stretched, it is difficult to produce a difference in elastic modulus, and the change in the linear cutting properties of the sliding layer itself is considered to be small.

[0116] On the other hand, a thinner sliding layer is less likely to impede the linear cutability of the substrate layer, which is therefore preferable. Therefore, to ensure that the thickness of the sliding layer is 8 μm or less as described above, the sliding layer can be a stretch film.

[0117] However, from the point of view of not hindering straight cutting, a thinner slip layer is better, and the most common means of making it thinner is stretching.

[0118] <Other Layers>

[0119] In addition to the adhesive layer, substrate layer, and sliding layer described above, the adhesive film of the present invention may also have other layers. For example, to improve the adhesion between the adhesive layer and the substrate layer, a coating layer may be provided between the adhesive layer and the substrate layer.

[0120] <Coating Layer>

[0121] The coating layer contains a resin with adhesive properties. Examples of adhesive resins include polyurethane resins, olefin copolymers, styrene resins, and ethyleneimine resins, and one or more of these can be used.

[0122] A coating layer can be formed by applying a coating liquid to the surface of a substrate layer and then drying it.

[0123] When the resin with good adhesion is a water-soluble resin such as an ethyleneimine-based resin, the resin can be dissolved in water to prepare a coating solution. The content of the ethyleneimine-based resin in the coating solution, converted from solid components, is preferably 2 parts by mass or more, more preferably 10 parts by mass or more, and on the other hand, preferably 40 parts by mass or less, more preferably 30 parts by mass or less. If the content is within this range, sufficient adhesion can be easily obtained.

[0124] When the resin with adhesive properties is a non-water-soluble resin such as a polyurethane resin, an olefin copolymer, or a styrene resin, it is possible to prepare a coating liquid comprising an emulsion in which the resin is dispersed in a dispersion medium. In this case, the coating layer will contain components of the emulsion (hereinafter, sometimes simply referred to as emulsion) from the resin particles.

[0125] Here, components from the emulsion refer to the residual components after the dispersion medium of the emulsion in the coating liquid used for the coating layer has evaporated. For example, residual components are resin particles in the emulsion and other components added as needed. These components may include modified bodies that have been modified during the formation of the coating layer. The resin particles in the residual components exist in particulate form in the coating layer, but may sometimes melt or deform due to overheating during printing.

[0126] An emulsion is a liquid formed by emulsifying or dispersing particulate resin particles in a dispersion medium. In this invention, resin particles refer to particulate resin particles dispersed in a dispersion medium to form an emulsion. From the viewpoint of ease of operation, an O / W emulsion formed by emulsifying or dispersing resin particles in an aqueous dispersion medium is preferred.

[0127] By including components from the emulsion in the coating layer, it is possible to achieve a tight fit with various laminates.

[0128] From an operational point of view, the volume average particle size of the resin particles contained in the emulsion is preferably 0.01 μm or more, more preferably 0.05 μm or more, and from the viewpoint of film formation and ink adhesion, it is preferably 3.0 μm or less, more preferably 2.0 μm or less. The volume average particle size of the resin particles is measured using a laser diffraction type particle size distribution measuring device (manufactured by Shimadzu Corporation: SALD-2200).

[0129] From the viewpoint that emulsions with the above-mentioned particle size can be easily obtained, the content of resin particles in the emulsion is preferably 5% to 80% by mass.

[0130] From the viewpoint of printability and emulsion adjustability, the content of solid components from the emulsion in the coating layer is preferably 10% to 99% by mass relative to the total solid components of the coating layer.

[0131] It should be noted that the application solution can be used alone or in combination with the above-mentioned aqueous solution or emulsion.

[0132] <<Other Ingredients>>

[0133] The coating layer may contain other additives such as antistatic agents as needed, within the limits of not compromising the seal.

[0134] <<<Antistatic Agent>>>

[0135] Antistatic agents can reduce dust adhesion caused by the charged surface of the film or malfunctions caused by static electricity during printing.

[0136] As an antistatic agent, there are no particular limitations; cationic, anionic, amphoteric, or nonionic antistatic agents can be used.

[0137] As an antistatic agent, nitrogen-containing polymeric antistatic agents are preferred, and acrylic resins containing tertiary or quaternary nitrogen are more preferred.

[0138] These antistatic agents can be used alone or in combination of two or more.

[0139] The amount of antistatic agent added to the coating solution, converted from solid components, is preferably 5 parts by weight or more, and more preferably 60 parts by weight or less. If the amount of antistatic agent added is above the lower limit mentioned above, antistatic properties are easily obtained; if it is below the upper limit mentioned above, sufficient adhesion is easily obtained.

[0140] <<Coating thickness>>

[0141] The thickness of the coating layer is preferably 0.05 μm or more, more preferably 0.1 μm or more. On the other hand, it is preferably 5 μm or less, more preferably 1 μm or less. If the thickness is within this range, sufficient adhesion can be easily obtained.

[0142] <Properties of Adhesive Films>

[0143] In addition to having high adhesive and peel properties, the adhesive film of the present invention having the above-described structure also has excellent cutability.

[0144] It should be noted that, from the viewpoint of strength and toughness, the thickness of the adhesive film of the present invention is preferably 20 μm or more, more preferably 40 μm or more, and particularly preferably 60 μm or more. From the viewpoint of linear cutting ability and increasing the number of rolls when rolling, it is preferably 550 μm or less, more preferably 300 μm or less, particularly preferably 150 μm or less, and most preferably 100 μm or less.

[0145] <Adhesive Properties>

[0146] The adhesive strength of the adhesive film of the present invention is preferably 50 mN / 25 mm or more, more preferably 80 mN / 25 mm or more, and further preferably 1000 mN / 25 mm or less, more preferably 500 mN / 25 mm or less. By ensuring the adhesive strength is above or below the aforementioned lower limit, a good adhesive effect can be obtained. On the other hand, when it is below the aforementioned upper limit, the adhesive strength is not too strong and therefore inconvenient to handle. It should be noted that the adhesive strength was measured according to JIS Z 0237:2000.

[0147] <Peeling characteristics>

[0148] The peel strength of the adhesive film of the present invention, when two adhesive films are laminated in such a manner that the sliding layer of one film overlaps the adhesive layer of the other, is preferably 0.01 mN / 15 mm or more, more preferably 0.1 mN / 15 mm or more. By setting the peel strength to the lower limit or above, an adhesive film with excellent peel resistance in use can be obtained.

[0149] Furthermore, the peel force is preferably 3 mN / 15 mm or less, more preferably 1 mN / 15 mm or less. By setting it below the above upper limit, an adhesive film with excellent peelability can be obtained.

[0150] It should be noted that the peel force was measured using a Tensilon universal testing machine (trade name: RTM-250, manufactured by ORIENTEC Co., Ltd.).

[0151] <Adhesive film laminate>

[0152] The adhesive film laminate of the present invention is a laminate formed by stacking multiple adhesive films of the present invention in such a way that the adhesive layer and the sliding layer are in contact. The number of layers is not particularly limited; for example, when used as an adhesive cleaner, 3 to 500 is preferred. The laminate can be a laminate of multiple adhesive films, or it can be a laminate formed by winding a thin strip of adhesive film.

[0153] <Method for manufacturing adhesive films>

[0154] The adhesive film of the present invention can be manufactured by sequentially stacking an adhesive layer, a substrate layer, and a sliding layer, and the manufacturing method is not particularly limited. For example, the adhesive film of the present invention can be manufactured by forming a laminated film having a substrate layer and a sliding layer sequentially, and then applying a coating liquid for forming an adhesive layer onto the substrate layer to form an adhesive layer.

[0155] <Membrane Forming and Lamination>

[0156] As a film forming method, for example, molten resin can be extruded into sheets using single-layer or multi-layer T-dies, I-dies, etc., connected to a screw extruder, through methods such as casting, calendering, pressing, and blow molding. Alternatively, a mixture of thermoplastic resin and organic solvent or oil can be cast or calendered, and then the solvent or oil can be removed to form a film.

[0157] Examples of membrane lamination methods include co-extrusion, extrusion lamination, and coating, and combinations thereof are also possible. Co-extrusion involves laminating and extruding layers of resin compositions, melt-mixed in their respective extruders, within a feed block or manifold, simultaneously forming and laminating the membrane. Extrusion lamination involves extruding and laminating a resin composition onto a pre-formed membrane. Coating involves applying a resin solution, emulsion, or dispersion onto a membrane and then drying it to form and laminate the membrane.

[0158] <Stretching>

[0159] Each layer can be stretched individually before stacking, or stretched together after stacking. Alternatively, stretching can be performed again after stacking unstretched and stretched layers.

[0160] Examples of stretching methods for stretching films include: longitudinal stretching using the difference in circumferential speed of rollers, transverse stretching using a tenter furnace, successive biaxial stretching combining these methods, calendering, and simultaneous biaxial stretching. Additionally, simultaneous biaxial stretching (blow molding) can also be used.

[0161] When the resin used for the membrane is a non-crystalline resin, the stretching temperature during stretching is preferably in the range of above the glass transition temperature of the resin. Furthermore, when the resin is a crystalline resin, the stretching temperature is preferably in the range of above the glass transition temperature of the non-crystalline portion of the resin and below the melting point of the crystalline portion of the resin; specifically, it is preferably a temperature 2°C to 60°C lower than the melting point of the resin.

[0162] There is no particular limitation on the stretching speed, but from the point of view of stable stretching, it is preferably in the range of 20 m / min to 350 m / min.

[0163] Furthermore, the stretch ratio can be appropriately determined by considering the characteristics of the resin used. For example, when a resin film containing a homopolymer or copolymer of propylene is stretched in one direction, the lower limit of the stretch ratio is typically 1.2 times or more, preferably 2 times or more, while the upper limit is typically 12 times or less, preferably 10 times or less. For biaxial stretching, the lower limit of the stretch ratio, expressed as an area stretch ratio, is typically 1.5 times or more, preferably 10 times or more, while the upper limit is typically 60 times or less, preferably 50 times or less.

[0164] <Formation of the coating layer>

[0165] When a coating layer is provided between the adhesive layer and the substrate layer, it can be formed by preparing a coating liquid for forming the coating layer and applying it to the substrate layer. The coating liquid can be prepared by adding additives as needed to the above-mentioned resin aqueous solution or resin particle emulsion.

[0166] When using cationic polyurethane resin particles, an emulsion can be prepared by dispersing a copolymer in which cationic hydrophilic groups are introduced into the polyurethane resin backbone in water. Specifically, examples include: a method of polymerization in which monomers constituting the target polymer are emulsified and dispersed in water; and a method of obtaining the target polymer through bulk polymerization, followed by successive melt mixing and emulsification of the raw material resin using a twin-screw extruder.

[0167] There are no particular limitations on the preparation method of the emulsion when using resin particles of olefin copolymers, for example, the methods described in (1) or (2) below can be used.

[0168] (1) An olefin copolymer is added to an aromatic hydrocarbon solvent and heated to dissolve it, thus preparing a resin solution. A dispersant is added to the resin solution and the mixture is stirred. Then, water is added while the mixture undergoes a phase inversion. The aromatic hydrocarbon solvent is then removed by distillation, and the resulting aqueous dispersion is used as an emulsion.

[0169] (2) After melting the olefin copolymer using a twin-screw extruder, an aqueous solution of dispersant is added and the mixture is kneaded to obtain an aqueous dispersion, which is used as an emulsion (refer to Japanese Patent Publication No. 62-29447).

[0170] When preparing emulsions using these methods, it is preferable to use a cationic water-soluble polymeric emulsifier or other polymeric emulsifier as a dispersant, and even more preferable to use the dispersion method using a twin-screw extruder as described in (2) above. This allows for easy adjustment of the volume average particle size of the olefin copolymer resin particles in the emulsion to 0.01 μm to 3.00 μm. In the method described in (2) above, the volume average particle size of the olefin copolymer resin particles in the emulsion can be adjusted, for example, by controlling the amount of water relative to the olefin copolymer in the operating conditions of the twin-screw extruder, the barrel temperature and its curve, the residence time of the resin in the extruder, and the barrel rotation speed of the extruder.

[0171] The concentration of solid components in the coating solution relative to the total amount of the coating solution is preferably 0.1% by mass or more, more preferably 1% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less.

[0172] The coating liquid can be applied using coating equipment such as roller coaters, bar coaters, sizing press coaters, and sprayers.

[0173] The preferred application amount of the coating solution, based on the amount of solids after drying, is 0.05 g / m³. 2 The above, more preferably 0.10 g / m 2 The above, especially preferred, is 0.15 g / m 2 In addition, the preferred value is 1.40 g / m³. 2 The following is more preferably 0.50 g / m 2 The following is more preferably 0.30 g / m 2 The following is particularly preferred: 0.24 g / m 2 the following.

[0174] <Formation of the adhesive layer>

[0175] Adhesive layers can be formed by known methods such as coating (applying, spreading) and bonding with adhesives.

[0176] Example

[0177] The present invention will be further described in detail below with examples, but the present invention is not limited to the following examples. It should be noted that, unless otherwise specified, the terms "parts", "%", etc. in the examples refer to the description of mass standards.

[0178] [raw material]

[0179] The raw materials used in the examples and comparative examples are shown in the table below.

[0180] [Table 1]

[0181]

[0182] [Preparation of coating solution for coating layer]

[0183] (Dispersant (H))

[0184] Isopropanol (Tokuyama Corporation, trade name: TokusoIPA) 40 kg was added to a 150 L reactor equipped with a cooler, nitrogen inlet pipe, stirrer, monomer dropping funnel, and heating jacket. Then, while stirring, 12.6 kg of N,N-dimethylaminoethyl methacrylate (Sanyo Chemicals Co., Ltd., trade name: Methacrylate DMA), 12.6 kg of butyl methacrylate (Mitsubishi Rayon Co., Ltd., trade name: Acryester B), and 2.8 kg of higher alcohol methacrylate (Mitsubishi Rayon Co., Ltd., trade name: Acryester SL, a mixture of lauryl methacrylate and tridecyl methacrylate) were added. After nitrogen purging, the internal temperature was raised to 80 °C, and 0.3 kg of azobisisobutyronitrile (Wako Pure Chemical Industries Co., Ltd., trade name: V-60 (AIBN)) was added as a polymerization initiator to begin polymerization.

[0185] After polymerization at 80°C for 4 hours, the resulting copolymer was neutralized with 4.3 kg of glacial acetic acid (manufactured by Wako Pure Chemical Industries, Ltd.). Next, isopropanol was removed by distillation, and 48.3 kg of deionized water was added to displace the system, yielding an aqueous solution (35% by weight solids) of the neutralized cationic polymeric emulsifier containing the (meth)acrylic acid copolymer as a dispersant (H). The resulting polymeric emulsifier had a weight-average molecular weight of 40,000.

[0186] (Emulsion of polyurethane copolymer resin (E1))

[0187] A cationic polyurethane aqueous dispersion (trade name: HYDRAN CP-705, manufactured by DIC Corporation) was used as an emulsion (E1). The solids content of this emulsion (E1) was 25% by mass, and the volume average particle size of the resin particles in the emulsion (E1) was 0.07 μm. The volume average particle size was measured using a laser diffraction type particle size distribution measuring device (manufactured by Shimadzu Corporation: SALD-2200).

[0188] (Ethyleneimine-based resin solution (F))

[0189] In a four-necked flask equipped with a stirrer, reflux cooler, thermometer, and nitrogen inlet, 100 parts by weight of a 25% aqueous solution of polyethyleneimine (manufactured by Nippon Shokubai Co., Ltd., trade name: EPOMIN P-1000), 10 parts by weight of 1-chlorobutane (manufactured by Wako Pure Chemical Industries, Ltd., reagent), and 10 parts by weight of propylene glycol monomethyl ether (manufactured by Wako Pure Chemical Industries, Ltd., reagent) were introduced. The mixture was then stirred under a nitrogen stream and subjected to a modification reaction at 80°C for 20 hours. Next, water was added to the solution to adjust the solid content concentration to 20% by weight, yielding a solution of the ethyleneimine-based resin (F).

[0190] (Antistatic agent (G))

[0191] 35 parts by weight of N,N-dimethylaminoethyl methacrylate (manufactured by Mitsubishi Gas Chemical Co., Ltd., Japan), 20 parts by weight of ethyl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd., reagent), 20 parts by weight of cyclohexyl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd., reagent), 25 parts by weight of octadecyl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd., reagent), 150 parts by weight of ethanol, and 1 part by weight of 2,2'-azobis(isobutyronitrile) (manufactured by Wako Pure Chemical Industries, Ltd., reagent) were introduced into a four-necked flask equipped with a stirrer, a reflux condenser, a thermometer, and a dropping funnel. The system was purged with nitrogen, and the polymerization reaction was carried out at 80°C for 6 hours under a nitrogen atmosphere. Then, 85 parts by weight of a 50% aqueous solution of 3-chloro-2-hydroxypropyltrimethylammonium chloride (manufactured by Wako Pure Chemical Industries, Ltd., reagent) were added. After reacting at 80°C for 15 hours, water was added dropwise while distilling to remove ethanol, yielding a solution of an antistatic agent containing a quaternary ammonium salt copolymer with a solid content of 20% by mass.

[0192] (Application solution)

[0193] An aqueous solution comprising 13% by mass of the above-mentioned polyurethane resin emulsion (E 1), 0.5% by mass of the ethyleneimine resin solution (F), and 0.5% by mass of the antistatic agent (G) was prepared and used as a coating solution (1). It should be noted that the concentrations of the above components represent the solid component concentrations of each component relative to the overall coating solution.

[0194] [Manufacturing of adhesive films]

[0195] (Example 1)

[0196] A resin composition comprising 80 parts by weight of a polypropylene resin (NOVATEC PP FY-4) and 20 parts by weight of filler 1 (Softon 1800) was melt-blended using an extruder set to 230°C. The mixture was then fed into an extrusion die set to 250°C and extruded into a sheet. The sheet was cooled to 60°C using a cooling device to obtain an unstretched sheet. This unstretched sheet was heated to 135°C and stretched five times its original length along the flow direction (longitudinal direction) using the circumferential speed difference of the rollers to form the substrate layer 1.

[0197] Next, a resin composition comprising 60 parts by weight of a polypropylene resin and 40 parts by weight of filler 1 is melt-blended in an extruder set to 250°C and then extruded into a sheet on substrate layer 1. Thus, a substrate layer 2 containing the resin composition is laminated onto substrate layer 1.

[0198] On the other hand, 100 parts by weight of polyethylene resin (Novatec LD LC540) were melt-blended in an extruder set to 250°C. A resin composition containing 60 parts by weight of polypropylene resin and 40 parts by weight of filler 1 was melt-blended in another extruder set to 250°C. Then, a sliding layer containing polyethylene resin and a substrate layer 3 containing the resin composition were sequentially overlapped and co-extruded in a sheet form. Simultaneously, a sheet was extruded onto the main surface of the substrate layer 1, opposite to the main surface where the substrate layer 2 was stacked. Immediately afterwards, a pattern with an interval of 0.17 mm was embossed on the surface of the sliding layer using an embossing roller (150 lines per inch, reverse gravure type) composed of a metal roller and a rubber roller. Thus, a four-layer sheet consisting of substrate layer 2, substrate layer 1, substrate layer 3, and sliding layer stacked sequentially was obtained.

[0199] After cooling the obtained four-layer sheet to 60°C using a cooling device, the laminated sheet is heated to approximately 150°C using a tenter furnace and stretched 8.5 times in the direction perpendicular to the flow (transverse). Then, it is heated to 160°C for heat treatment, cooled to 60°C, and the edges are slit.

[0200] Next, a continuous coating apparatus was used to perform corona discharge treatment on the substrate layer 2 of the four-layer sheet. The energy density applied during the corona discharge treatment was set to 4200 J / m². 2 Next, a coating liquid is applied to substrate layer 2 and dried in a hot air drying apparatus at 60°C to form a coating layer. The solid content of the dried coating layer is 0.2 g / m³. 2 .

[0201] Thus, a five-layer sheet is obtained, consisting of a coating layer, a substrate layer 2, a substrate layer 1, a substrate layer 3, and a sliding layer stacked sequentially.

[0202] Total thickness of all layers: 74μm

[0203] Layer thickness: - / 20μm / 30μm / 20μm / 4μm

[0204] Number of stretching axes for each layer: - / Single axis / Dual axis / Single axis / Single axis

[0205] An acrylic resin (ORIBAIN BPS5978) is coated and dried on the coating layer to achieve a dry film thickness of 5 μm, and then an adhesive layer is laminated.

[0206] The adhesive film of Example 1 is manufactured through the above processes.

[0207] (Example 2)

[0208] By adjusting the amount of polyethylene resin extruded onto the substrate layer 1, the thickness of the sliding layer is made as described in the table below. Otherwise, the adhesive film is manufactured in the same manner as in Example 1.

[0209] (Example 3)

[0210] When forming the sliding layer, a composition containing 92 parts by weight of polyethylene resin and 8 parts by weight of filler 2 is used, and no embossing is performed. Otherwise, the adhesive film is manufactured in the same manner as in Example 1.

[0211] (Example 4)

[0212] When forming the sliding layer, no embossing process is performed; otherwise, the adhesive film is manufactured in the same manner as in Example 1.

[0213] (Comparative Example 1)

[0214] By adjusting the amount of polyethylene resin extruded onto the substrate layer 1, the thickness of the sliding layer is made as described in the table below. Otherwise, the adhesive film is manufactured in the same manner as in Example 1.

[0215] (Comparative Example 2)

[0216] In forming the sliding layer, a polypropylene resin is used instead of a polyethylene resin; otherwise, the adhesive film is manufactured in the same manner as in Example 1.

[0217] (Comparative Example 3)

[0218] When forming the sliding layer, the embossing roller with a groove depth of 8 times was changed. Otherwise, the adhesive film was manufactured in the same manner as in Comparative Example 2.

[0219] (Comparative Example 4)

[0220] When forming the sliding layer, a composition containing 90 parts by weight of polypropylene resin and 10 parts by weight of lubricant (aluminum stearate) was used, and no embossing was performed. Otherwise, the adhesive film was manufactured in the same manner as in Comparative Example 2.

[0221] <Evaluation of the elastic modulus of the adhesive layer>

[0222] The elastic modulus of the acrylic resin in the adhesive film was determined by the following method.

[0223] One drop of instant adhesive (manufactured by Toa Synthetic Co., Ltd., AronAlpha (registered trademark), professional impact-resistant adhesive) was applied to the surface of the support layer of the measuring device. The support layer and the adhesive layer of the adhesive film were bonded together using the instant adhesive. After fixing the adhesive film to the sample holder of the measuring device, the indentation modulus of the adhesive layer was measured. The measuring device used was the ELIONIX Co., Ltd. nanoindenter "ENT-2100". The measurement conditions were as follows: a triangular pyramidal diamond indenter (Berkovich indenter) with an inter-edge angle of 115° was used. The measurement mode was set as follows: load-unload test, maximum load: 3 μN, holding time at maximum load: 1 second, load speed / unload speed: 10 μN / sec. The obtained measurement data was processed using the dedicated analysis software (version 6.18) attached to the measuring device to calculate the elastic modulus (indentation modulus in the thickness direction) (MPa) of the acrylic resin.

[0224] <Evaluation of the elastic modulus of adhesive films>

[0225] The adhesive film was cut into test pieces measuring 30 mm in length and 15 mm in width. Dynamic viscoelasticity was measured in both the flow direction and the vertical direction using a solid viscoelasticity measuring apparatus (manufactured by TA Instruments Japan Inc.: RSA-III). The measurement conditions were set as follows: chuck distance 20 mm, measurement frequency 10 Hz, strain 0.1%, heating rate 10 °C / min, and tensile mode. The storage modulus at 23 °C was set as the tensile modulus.

[0226] <Surface Roughness Evaluation of Sliding Layer>

[0227] The surface roughness of the sliding layer was measured according to JIS-B-0601:2001.

[0228] <Evaluation of Adhesive Strength>

[0229] The adhesive strength of the adhesive layer in an adhesive film is determined as follows: two adhesive films are stacked with the sliding layer of one film overlapping the adhesive layer of the other film, pressure is applied, and the film is then peeled off and the adhesion is measured.

[0230] Pressure conditions: Bonding area 200mm×25mm, pressure 4MPa, pressure time 5 minutes. Peeling conditions: Peeling angle 180°, peeling speed 300mm / min.

[0231] The peel strength of the adhesive layer after peeling was determined according to JIS Z 0237:2000. Specifically, the adhesive film was cut into test pieces with a length of 200 mm and a width of 25 mm. The adhesive layer was attached to a substrate SUS430BA board whose surface had been cleaned with toluene. A 2 kg roller was used to press the substrate against the substrate by rubbing it back and forth once on the surface of the support layer. After pressing for 30 minutes, the test piece was peeled off in a 180° direction at a tensile speed of 300 mm / min, and the adhesive strength was measured. The adhesive strength was evaluated according to the following criteria.

[0232] A: 50 [mN / 25mm] or higher (Good)

[0233] C: Less than 50 [mN / 25mm] (Unacceptable)

[0234] <Evaluation of the peelability of the sliding layer and adhesive layer>

[0235] Two adhesive films are stacked with one lubricating layer overlapping the other adhesive layer, and then peeled off under pressure.

[0236] Pressure conditions: bonding area 200mm×5mm, pressure 4MPa, pressure time 5 minutes

[0237] Peeling conditions: peeling angle 180°, peeling speed 300 mm / min

[0238] The peel force was measured three times under the above conditions, and the average value was taken as the peel force [mN / 15mm]. A Tensilon universal testing machine was used as the measuring apparatus.

[0239] The peeling force value is evaluated from the following two perspectives.

[0240] (Difficulty of offset during use (peel resistance))

[0241] A: Above 0.01 [mN / 15mm] (Good)

[0242] C: Less than 0.01 [mN / 15mm] (Unacceptable)

[0243] (Smoothness during peeling (ease of peeling))

[0244] A: Below 1 [mN / 15mm] (Good)

[0245] B: Greater than 1 [mN / 15mm] and less than 3 [mN / 15mm] (Pass)

[0246] C: Above 3 [mN / 15mm] (unacceptable)

[0247] <Linear cutting properties (cutting ability) of adhesive films>

[0248] The following steps are used to conduct an evaluation experiment to assess the straight-line cutting performance.

[0249] (1) Cut the adhesive film into test samples with a width of 20mm and a length of 297mm, and prepare 10 sets.

[0250] (2) Make a 1mm cut in the center of the short side of the sample with a knife to prepare it by tearing in a direction perpendicular to the flow direction (TD direction).

[0251] (3) At a speed of 300 m / min, form an angle of 180° and tear along the TD direction starting from the incision.

[0252] If the tear extends to the shorter side on the opposite side, add 1 point. Perform the same test 10 times and evaluate based on the following criteria.

[0253] A: 9 points or above (Good)

[0254] B: 7-8 points (passing)

[0255] C: Below 6 points (unqualified)

[0256] The evaluation results are shown in the table below.

[0257] [Table 2]

[0258] Table 2

[0259]

[0260] PP: Polypropylene; PE: Polyethylene

[0261] Based on the above results, the adhesive strength, peelability, and straight-line cutting performance of the adhesive film in the embodiments are all A (good) or B (qualified). Furthermore, a comparison of Embodiment 4 with Embodiments 1 and 3 shows that by utilizing embossing and adding fillers to set the surface roughness of the sliding layer to an appropriate range, the ease of peeling after use is further improved.

[0262] On the other hand, the adhesive film of Comparative Example 1, with its thicker sliding layer, exhibited reduced linear cutting properties. The adhesive films of Comparative Examples 2 and 3, which used acrylic resin in the sliding layer, showed reduced peel resistance during use, even after embossing the sliding layer; in fact, the adhesive performance of Comparative Example 3, which underwent enhanced embossing, deteriorated. The adhesive film of Comparative Example 4, which used acrylic resin in the sliding layer and contained a lubricant, resulted in good peel resistance and linear cutting properties, but significantly reduced adhesive performance.

[0263] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is based on Japanese Patent Application No. 2021-055636, filed on March 29, 2021, the contents of which are incorporated herein by reference.

[0264] Industrial availability

[0265] The adhesive membrane of the present invention is useful for adhesive cleaners used to remove dust, fibers, particles, etc.

[0266] The adhesive film of this invention can also be used as transparent tape and float tags.

[0267] Explanation of reference numerals in the attached figures

[0268] 10…Adhesive film, 1…Substrate layer, 2…Sliding layer, 3…Adhesive layer

Claims

1. An adhesive film, characterized in that, It is an adhesive film having an adhesive layer, a substrate layer, and a sliding layer in sequence, wherein, The adhesive layer contains an adhesive resin with an elastic modulus of less than 100 MPa. The substrate layer is a thermoplastic resin film. The sliding layer comprises polyethylene resin and has a thickness of 6 mm. μ The surface roughness is less than m and the surface roughness is 0.

05. μ m or more and 5 μ Below m, the surface roughness is based on the three-dimensional center surface average roughness according to JIS-B-0601:2001. The elastic modulus E in the flow direction of the adhesive film MD Elastic modulus E in the vertical direction TD The absolute value of the difference, |ΔE|, is above 500 MPa.

2. An adhesive film, characterized in that, It is an adhesive film having an adhesive layer, a substrate layer, and a sliding layer in sequence, wherein, The adhesive layer contains an adhesive resin with an elastic modulus of less than 100 MPa. The substrate layer is a thermoplastic resin film comprising polypropylene resin and fillers. The sliding layer comprises polyethylene resin and has a thickness of 6 mm. μ Below m The elastic modulus E in the flow direction of the adhesive film MD Elastic modulus E in the vertical direction TD The absolute value of the difference, |ΔE|, is above 500 MPa.

3. An adhesive film, characterized in that, It is an adhesive film having, in sequence, an adhesive layer, a coating layer, a substrate layer, and a sliding layer, wherein, The adhesive layer contains an adhesive resin with an elastic modulus of less than 100 MPa. The coating layer contains one or more resins selected from polyurethane resins, olefin copolymers, styrene resins, and ethyleneimine resins. The substrate layer is a thermoplastic resin film. The sliding layer comprises polyethylene resin and has a thickness of 6 mm. μ Below m The elastic modulus E in the flow direction of the adhesive film MD Elastic modulus E in the vertical direction TD The absolute value of the difference, |ΔE|, is above 500 MPa.

4. An adhesive film, characterized in that, It is an adhesive film having an adhesive layer, a substrate layer, and a sliding layer in sequence, wherein, The adhesive layer contains an adhesive resin with an elastic modulus of less than 100 MPa. The substrate layer is a thermoplastic resin film. The sliding layer comprises polyethylene resin and has a thickness of 6 mm. μ Below m, and being a uniaxially stretched resin film, The elastic modulus E in the flow direction of the adhesive film MD Elastic modulus E in the vertical direction TD The absolute value of the difference, |ΔE|, is above 500 MPa.

5. The adhesive film according to any one of claims 1 to 4, wherein, The substrate layer is porous.

6. An adhesive film laminate, characterized in that, The adhesive film according to any one of claims 1 to 4 is laminated in such a way that the adhesive layer and the sliding layer are in contact.

Images