JP6146090B2 - Adhesive film and method for producing adhesive film - Google Patents

Description

  The present invention relates to an adhesive film used for, for example, a light peeling application.

  The pressure-sensitive adhesive film is classified into light peel (fine peel), medium peel, heavy peel, etc. according to the peel strength (adhesive strength) with the adherend, and the peel strength is adjusted by adjusting the composition of the pressure-sensitive adhesive layer. Generally, it is determined by the thickness (see Patent Document 1).

  In this type of pressure-sensitive adhesive film, when the peel strength of the pressure-sensitive adhesive layer is insufficient, it is common to add a rosin tackifier (tackifier) or the like to the pressure-sensitive adhesive. However, when a tackifier is added to the pressure-sensitive adhesive, there is a problem that the cohesive force is lowered. As a result, when the pressure-sensitive adhesive film is peeled off, so-called adhesive residue is generated, and in applications where stress is applied to the pressure-sensitive adhesive layer for a long period of time, the holding power decreases with the passage of time, and the durability decreases.

  Also, in so-called light peeling applications, delicate strength control is required because the peeling strength is low, but it is particularly difficult to perform this strength control only with the composition and thickness. There was a need for a method to control.

JP 2011-231335 A

  This invention is made | formed in view of such a condition, It aims at enabling the improvement and adjustment of peeling strength, without changing the composition of an adhesive layer about the adhesive film of a light peeling use. .

  The present inventor has conducted extensive research to solve the above problems, and forms a pressure-sensitive adhesive layer having a predetermined thickness on the surface of a base material provided with a microprojection layer by closely arranging tapered microprojections according to the moth-eye structure. And the present invention has been completed.

  Specifically, the present invention provides the following.

(1) A base material provided with a microprojection layer on which at least one side has a microprojection layer in which tapered microprojections having a height of 100 nm or more and 300 nm or less are closely formed at intervals of 50 nm or more and 500 nm or less;
An adhesive film comprising an adhesive layer formed on the microprojection layer,
The pressure-sensitive adhesive layer is a pressure-sensitive adhesive film having an average thickness of 100 nm to 2000 nm.

  According to (1), since the specific surface area of the substrate is increased by about 6 times compared to the plane due to the microprojection layer within the predetermined range, the adhesive layer can be held on the substrate with a wide surface area. it can. This increases the peel strength between the substrate and the adhesive layer. Furthermore, by making the pressure-sensitive adhesive layer as thin as 0.1 μm or more and 2.0 μm or less, it was found that the unevenness of the microprojection layer of the base material also affects the surface state of the pressure-sensitive adhesive layer serving as the adhesive surface. Utilizing it, it was possible to improve and adjust the peel strength between the adhesive layer and the adherend to be adhered. For this reason, the peel strength between the pressure-sensitive adhesive layer and the adherend can be improved and finely adjusted without changing the composition of the pressure-sensitive adhesive layer itself. Moreover, in the aspect by which a release film is laminated | stacked on an adhesive layer, it can utilize as adjustment of the peeling strength of a release film.

  (2) In (1), the microprojection layer is formed by a molding process using a molding die having micro holes formed by repeating an anodizing process and an etching process. Is preferred.

  According to (2), the uneven shape on the surface of the microprojection layer can surely affect the surface of the pressure-sensitive adhesive layer, thereby reliably holding the pressure-sensitive adhesive layer on the pressure-sensitive adhesive material with a large surface area. be able to.

(3) a step of creating a microprojection layer that forms a microprojection layer by closely creating a tapered microprojection on the surface on one side of the substrate;
A pressure-sensitive adhesive layer creating step for creating a pressure-sensitive adhesive layer on the microprojection layer,
The step of creating the microprojections includes
A process for creating a mold for molding that creates a mold for molding having micro holes created by repetition of anodizing and etching;
A pressure-sensitive adhesive film manufacturing method comprising: a molding processing step of creating the microprojection layer by molding processing using the molding die.

  According to (3), the pressure-sensitive adhesive film of (1) can be produced, and the pressure-sensitive adhesive layer can be held on the substrate with a large surface area by the fine protrusion layer, and the influence of the irregularities of the fine protrusion layer can be influenced by the pressure-sensitive adhesive layer. It can hold | maintain to the to-be-adhered material in the state exerted on the surface of this, and, thereby, improvement and adjustment of peeling strength can be performed simply.

  About the adhesive film for light peeling uses, it becomes possible to improve and adjust the peeling strength without changing the composition of the adhesive layer.

It is sectional drawing which shows the adhesive film which concerns on 1st Embodiment of this invention. It is a figure which shows a manufacturing process. It is a figure which shows a roll version. It is a figure which shows the preparation process of a roll plate. It is a chart which shows an experimental result. 6 is a chart showing experimental results different from FIG.

[First Embodiment]
FIG. 1 is a cross-sectional view showing an adhesive film according to the first embodiment of the present invention. This adhesive film 1 is used for the purpose of temporarily fixing or protecting a component, for example, in a manufacturing process of an electronic component, and is configured so that it can be easily peeled off by irradiation with ultraviolet rays when it is no longer necessary to be fixed or protected. For this reason, the adhesive film 1 is provided with the microprojection layer 3 and the adhesive layer 4 in this order on the surface of one side of the substrate 2.

〔Base material〕
As the base material 2, various film materials and sheet materials can be applied according to the purpose of use of the adhesive film 1. In this embodiment, a transparent film material capable of transmitting ultraviolet rays is applied to the substrate 2 by making it easily peelable by irradiation with ultraviolet rays. More specifically, in this embodiment, a TAC (Triacetylcellulose) film is applied to the substrate 2.

  However, various materials can be applied to the base material 2, for example, a polyester resin, a polyvinyl chloride resin, a fluorine resin, a polystyrene resin, a poly (meth) acrylic resin, a cellulose resin, and a polycarbonate resin. Examples thereof include synthetic resin films made of a known resin such as a resin, a polyimide resin, a polyolefin resin, a polyvinyl alcohol resin, a polyimide resin, a phenol resin, and a polyurethane resin. These can be used alone or in combination of two or more. Moreover, the base material 2 may be a single layer or a laminate of two or more layers. From the viewpoint of mechanical strength, a uniaxially stretched or biaxially stretched film is preferred. Since the adhesive film of the present invention is used to temporarily fix or protect an electronic component in the manufacturing process of the electronic component, the heat resistance, dimensional stability, energy ray permeability, flexibility, strength, etc. In addition, it is preferable to use a polyester-based resin that is also excellent in rigidity, extensibility, stackability, and chemical resistance.

  Examples of the polyester-based resin include polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, polyarylate, polytetramethylene terephthalate, etc. Among them, polyethylene that is easy to handle and low in price is used. Terephthalate is particularly preferred.

  Although the thickness of the base material 2 is not specifically limited, It is preferable that it is 30-300 micrometers, and it is more preferable that it is 50-100 micrometers. If it is the said range, since the form of the adhesive film 1 can be maintained, workability | operativity, such as sticking and peeling of the adhesive film 1, is good. In addition, since warp, slack, breakage and the like hardly occur and sufficient mechanical strength is exhibited, it is also possible to supply and process in a continuous belt shape. Furthermore, in the manufacturing process of the electronic component, it is possible to appropriately protect the surface of the electronic component that is the adherend. If the thickness exceeds the above-mentioned thickness, excessive performance may increase the cost.

  The formation method of the base material 2 is not specifically limited, For example, conventionally well-known film forming methods, such as a solution casting method, a melt extrusion method, and a calendar method, can be used. Moreover, you may use the commercially available base material previously formed into the film form by the said method, Furthermore, it is a corona treatment, a plasma treatment, an ozone treatment, a flame treatment, a primer treatment, vapor deposition on one side or both sides as needed. You may perform a process, an alkali treatment, etc.

[Microprojection layer]
The microprojection layer 3 is formed by closely providing microprojections having a tapered shape (a shape in which a cross-sectional area gradually decreases toward the tip). More specifically, the microprotrusions according to the microprojection layer 3 are microprojections according to the moth-eye structure, and in this embodiment, microholes are created in close contact by alternating repetition of anodizing treatment and etching treatment. It is created by a molding process using a mold for molding.

  For this reason, in this embodiment, the microprojection layer 3 is formed after an uncured resin layer (hereinafter, referred to as a receptor layer as appropriate) is formed as a receptor layer having a fine irregular shape related to such a microprojection. When the receiving layer is subjected to a molding treatment and cured using a molding die, the fine protrusions are closely arranged. In this embodiment, an acrylate-based ultraviolet curable resin, which is one of the molding resins used for the molding process, is applied to the receiving layer, whereby an ultraviolet curable resin layer is formed on the substrate 2. The microprojection layer 3 is formed by the shaping process.

  By providing the pressure-sensitive adhesive layer 4 through the microprojection layer 3 in this way, the pressure-sensitive adhesive layer 4 is held on the base material 2 with a remarkably large surface area as compared with the case where it is directly provided on the surface of the base material 2. Will be. Thereby, the adhesive force of the adhesive layer 4 with respect to the base material 2 can be markedly increased without providing a tackifier.

  Further, when the pressure-sensitive adhesive layer 4 is provided through the microprojection layer 3 in this way, the influence of the surface shape of the microprojection layer 3 also appears on the surface of the pressure-sensitive adhesive layer 4. The adhesive force between the pressure-sensitive adhesive body can also be increased without providing a tackifier. Accordingly, in this embodiment, the reduction in cohesive force is effectively avoided to increase the peel strength.

  In this way, by increasing the adhesive force so that the influence of the surface shape of the microprojection layer 3 also appears on the surface of the pressure-sensitive adhesive layer 4, the pressure-sensitive adhesive layer 4 becomes the surface of the microprojection layer 3 as a lower layer. It is preferable to create a thin film so that the uneven shape of the film appears on the surface. In addition, the minute protrusions are preferably made of a material having a certain degree of flexibility because the contact area with the adherend can be effectively secured by providing the flexibility.

  The moth-eye structure generally uses the principle of a moth-eye structure to prevent reflection by continuously changing the refractive index for incident light in the thickness direction of the substrate. For this reason, in general, the microprotrusions are set so that the distance between adjacent protrusions is equal to or less than the shortest wavelength for preventing reflection. For example, when preventing reflection of the visible light gland, the distance d between adjacent protrusions is d ≦ 300 nm. A more preferable condition is d ≦ 200 nm.

  However, in this embodiment, the purpose of preventing such reflection is not to increase the adhesive force by effectively utilizing the large surface area related to the moth-eye structure. In accordance with the above, the interval between the minute protrusions may be set to 50 nm or more and 500 nm or less. If it is less than 50 nm or more than 500 nm, the improvement of the peel strength and the adjustment effect of the present invention cannot be obtained. Further, the height of the fine protrusion is 100 nm or more and 300 nm or less, and if it is less than 100 nm or more than 300 nm, the improvement of the peel strength and the adjustment effect of the present invention cannot be obtained.

  The interval between the minute protrusions is proportional to the applied voltage in an anodic oxidation process described later, and can be set to a desired interval by controlling the applied voltage. Further, the minute protrusions may be arranged regularly or irregularly. In the case of irregular arrangement, the maximum and minimum values of the interval between adjacent minute protrusions can be obtained by statistical processing.

[Adhesive layer]
The pressure-sensitive adhesive layer 4 is made of, for example, a pressure-sensitive adhesive layer forming material containing a pressure-sensitive adhesive, and if necessary, an active energy ray-curable compound and a crosslinking agent. Various materials applicable to this type of adhesive film can be applied to the adhesive layer 4. However, as described above, the average thickness is 100 nm or more and 2000 nm or less from the viewpoint that the surface shape of the microprojection layer 3 appears on the surface of the pressure-sensitive adhesive layer 4 to increase the adhesive force. If the thickness is less than 100 nm, the absolute adhesive strength is insufficient and the coating is difficult. If the thickness exceeds 2000 nm (2 μm), the unevenness of the microprojection layer 3 does not appear on the surface of the pressure-sensitive adhesive layer 4. Can't get.

[Adhesive]
Here, the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer forming material is not particularly limited as long as it has a desired pressure-sensitive adhesive force. For example, acrylic, urethane-based, rubber-based, silicone-based, etc. Although an adhesive is mentioned, Among these, the acrylic adhesive which is excellent in durability, such as heat resistance, and transparency, and low cost is preferable. Examples of the acrylic pressure-sensitive adhesive include an acrylic ester copolymer obtained by copolymerizing an acrylic ester and another monomer. Examples of the acrylate ester include ethyl acrylate, acrylate-n-butyl, acrylate-2-ethylhexyl, isooctyl acrylate, isononyl acrylate, hydroxylethyl acrylate, propylene glycol acrylate, acrylamide, glycidyl acrylate, and the like. These may be used alone or in combination of two or more.

  Examples of the other monomer include, for example, methyl acrylate, methyl methacrylate, styrene, acrylonitrile, vinyl acetate, acrylic acid, methacrylic acid, itaconic acid, hydroxylethyl acrylate, hydroxylethyl methacrylate, propylene glycol acrylate, Examples include acrylamide, methacrylamide, glycidyl acrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, tert-butylaminoethyl methacrylate, n-ethylhexyl methacrylate, and the like. These may be used alone or in combination of two or more. Also good.

  The unit ratio of the acrylate ester contained in the acrylate copolymer and the other monomer (acrylate ester / other monomer) is not particularly limited as long as it exhibits a desired initial adhesive force. It is not limited and can be set as appropriate according to the purpose. Further, the mass average molecular weight (Mw) of the acrylate copolymer is not particularly limited as long as it exhibits a desired initial adhesive force, but is within the range of 100,000 to 1,500,000. Is preferable, and it is more preferable to be in the range of 200,000 to 1,000,000. If it is the said range, sufficient initial adhesive force can be exhibited, and it can be set as the adhesive layer of sufficient intensity | strength. In addition, the said mass mean molecular weight is a value of polystyrene conversion at the time of measuring by gel permeation chromatography (GPC).

[Active energy ray-curable compound]
The pressure-sensitive adhesive layer forming material may contain an active energy ray-curable compound and a polymerization initiator. The active energy ray-curable compound is a compound that is cured by irradiation with active energy rays. In this embodiment, ultraviolet rays are applied to the active energy glands, and the active energy ray-curable compound is an ultraviolet ray curable compound. Is done. However, it is not particularly limited, and examples thereof include a photo radical polymerizable compound, a photo cation polymerizable compound, a photo anion polymerizable compound, and a photo dimerizable compound. Among these, a photoradical polymerizable compound is preferable. This is because the curing speed is high, and a wide variety of compounds can be selected. Furthermore, physical properties such as adhesiveness before curing and peelability after curing can be easily controlled to desired ones. . Examples of the photoradical polymerizable compound include monomers such as polyfunctional acrylates, polyfunctional methacrylates, urethane acrylates, urethane methacrylates, polyester acrylates, polyester methacrylates, and epoxy acrylates, oligomers, and the like. Among these, polyfunctional acrylate and polyfunctional methacrylate are preferable, and trimethylol methane triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, dipentaerythritol hexaacrylate, dipentaerythritol penta Unsaturated compounds containing three or more acryloyl groups in one molecule such as acrylate, pentaerythritol triacrylate, ethylene oxide or propylene oxide adduct thereof are more preferable. These are functions that, when irradiated with active energy rays, harden the pressure-sensitive adhesive composition by three-dimensional crosslinking to reduce the pressure-sensitive adhesive force and increase the cohesive strength of the pressure-sensitive adhesive so that it does not transfer to the adherend surface. It is because it has.

  Examples of active energy rays include rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, and infrared rays, electromagnetic waves such as X rays and γ rays, electron beams, proton rays, and neutron rays. In view of the curing speed, the availability of the irradiation device, the price, etc., curing by ultraviolet irradiation is preferable.

  The amount of the active energy ray-curable compound contained in the pressure-sensitive adhesive layer forming material is preferably 1 to 80 parts by mass, more preferably 1 to 60 parts by mass with respect to 100 parts by mass of the pressure-sensitive adhesive. . By adjusting the amount of the active energy ray-curable compound, the adhesive strength after irradiation with the active energy ray can be controlled. When the amount of the active energy ray-curable compound is less than the lower limit of the above range, the crosslink density after irradiation with the active energy ray is not sufficient, and proper peelability may not be realized. In addition, if the amount of the active energy ray-curable compound is larger than the upper limit of the above range, not only the adhesive strength at the time of adhering the adherend is decreased, but also the tack before irradiation with active energy rays is remarkably increased or agglomerated. Since the force is reduced, during the production, the pressure-sensitive adhesive may protrude and contaminate the guide roll, or adhesive residue may be generated on the adherend.

[Crosslinking agent]
Although a crosslinking agent will not be specifically limited if it can bridge | crosslink with the said adhesive, An epoxy type crosslinking agent and an isocyanate type crosslinking agent are preferable. Examples of the isocyanate-based crosslinking agent include polyisocyanate compounds, trimers of polyisocyanate compounds, urethane prepolymers having terminal isocyanate groups obtained by reacting polyisocyanate compounds and polyol compounds, and such urethane prepolymers. These trimers can be used. The polyisocyanate compound is not particularly limited, and 2,4-tolylene diisocyanate, 2,5-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane-4,4'- Examples thereof include diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, dicyclohexylmethane-2,4′-diisocyanate, and lysine isocyanate.

  As the epoxy-based crosslinking agent, for example, a polyfunctional epoxy-based compound can be used. As polyfunctional epoxy-based compounds, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, neopentyl glycol diglycidyl ether, Examples include 1,6-hexanediol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and polybutadiene diglycidyl ether.

  The amount of the crosslinking agent contained in the pressure-sensitive adhesive layer-forming material varies depending on the type of the crosslinking agent. For example, in the case of an isocyanate-based crosslinking agent, 0.05 to 10 mass with respect to 100 parts by mass of the pressure-sensitive adhesive. Part is preferable, and 0.1 to 10 parts by mass is more preferable. If it is the said range, the adhesiveness of an adhesive layer and a base material can be improved. If the amount of the isocyanate-based crosslinking agent is less than the lower limit of the above range, the adhesion between the pressure-sensitive adhesive layer and the substrate becomes insufficient, or it becomes difficult for the pressure-sensitive adhesive layer to have sufficient strength, and the wafer When peeling from an adherend such as the above, the pressure-sensitive adhesive layer may cause cohesive failure to cause adhesive residue. If the amount of the isocyanate-based crosslinking agent is larger than the upper limit of the above range, the adhesive strength is lowered and does not sufficiently adhere to the adherend, or remains as an unreacted monomer in the adhesive layer, and the cohesive strength is increased. It may decrease.

  Moreover, in the case of an epoxy-type crosslinking agent, it is preferable that it is 0.05-10 mass parts with respect to 100 mass parts of adhesives, It is more preferable that it is 0.2-10 mass parts, 2-10 The part by mass is particularly preferred. If it is the said range, the desired adhesive force and cohesion force before active energy ray irradiation can be controlled. When the amount of the epoxy crosslinking agent is less than the lower limit of the above range, it becomes difficult for the pressure-sensitive adhesive layer to have sufficient strength, and the pressure-sensitive adhesive layer causes cohesive failure when peeled off from an adherend such as a wafer. , Glue residue may occur. When the amount of the epoxy-based crosslinking agent is larger than the upper limit of the above range, the adhesive force before irradiation with active energy rays is reduced.

[Other ingredients]
As the polymerization initiator used in combination with the active energy ray-curable compound, a photopolymerization initiator is preferable. According to the photopolymerization initiator, the sensitivity of the active energy ray-curable compound is enhanced, so that the polymerization curing time by the active energy ray and the active energy ray irradiation amount can be reduced. When the active energy ray-curable compound is a radical photopolymerizable compound, the type of the photopolymerization initiator is not particularly limited. For example, acetophenones, benzophenones, hydroxycyclohexyl phenyl ketone, Michler benzoyl Examples include benzoate, α-amyloxime ester, tetramethylthiuram monosulfide, and thioxanthones. These photopolymerization initiators may be used by mixing with a photosensitizer such as n-butylamine, triethylamine, or tri-n-butylphosphine. In addition, it is preferable that the quantity of the photoinitiator contained in the adhesive layer formation material is 0.05-10 mass parts with respect to 100 mass parts of adhesives, and is 0.1-10 mass parts. It is more preferable, and it is especially preferable that it is 1-3 mass parts. If the amount of the photopolymerization initiator is less than the lower limit of the above range, the polymerization initiation reaction is not sufficient, the adhesive strength after irradiation with active energy rays becomes excessively high, and there is a case where proper peelability cannot be realized. is there. When the amount of the photopolymerization initiator is larger than the upper limit of the above range, the active energy ray reaches only in the vicinity of the active energy ray irradiation surface, and curing may be insufficient. In addition, the cohesive force is reduced, which may cause adhesive residue on the adherend.

  The pressure-sensitive adhesive layer-forming material may contain various additives such as an antistatic agent, an anti-aging agent, and a tackifier as needed, as long as the object of the present invention is not impaired.

The method for forming the pressure-sensitive adhesive layer is not particularly limited. For example, the pressure-sensitive adhesive layer forming material such as the above-mentioned pressure-sensitive adhesive, active energy ray-curable compound, or crosslinking agent is diluted with a suitable solvent, and pressure-sensitive adhesive Examples thereof include a method in which a layer forming coating solution is prepared, and then the pressure sensitive adhesive layer forming coating solution is applied to a substrate by printing or coating and dried. Examples of the forming method by printing include a gravure printing method, a flexographic printing method, and an offset printing method. Examples of the coating method include roll coating, reverse coating, comma coating, knife coating, die coating, and gravure coating. The solvent to be diluted is not particularly limited as long as it can dissolve or disperse the pressure-sensitive adhesive layer forming material. For example, toluene, methyl ethyl ketone and the like are preferable. Moreover, the coating amount of the coating solution for forming the pressure-sensitive adhesive layer varies depending on the type of the active energy ray-curable compound, but is 5 to 30 g / m.
² is preferable. If the coating amount is less than the lower limit of the above range, sufficient adhesive strength may not be obtained. If the coating amount is larger than the upper limit of the above range, excessive performance may be caused and the cost may be increased. The average thickness of the pressure-sensitive adhesive layer after drying is adjusted to be 100 nm (0.1 μm) to 2000 nm (2 μm). Here, the average thickness is calculated from the coating amount (wet coating thickness) and the solid content rate.

〔Manufacturing process〕
The pressure-sensitive adhesive film 1 is a roll plate that is a mold for molding to be used for creating minute protrusions in the mold creating process. Further, in the molding process, the microprojection layer 3 is created on the substrate 2 by the molding process using the roll plate, and in the subsequent adhesive layer creation process, the adhesive layer 4 is created.

  FIG. 2 is a diagram illustrating a manufacturing process according to the shaping process and the pressure-sensitive adhesive layer creation process. In the manufacturing process 10, in the resin supply process, an uncured and liquid ultraviolet curable resin that forms a microprojection-shaped receiving layer is applied to the base material 2 in the form of a belt-shaped film by the die 12. In addition, about application | coating of an ultraviolet curable resin, not only the case by the die | dye 12 but various methods are applicable. Subsequently, in the manufacturing process 10, the pressing roller 14 presses and presses the substrate 2 against the peripheral side surface of the roll plate 13, thereby bringing the liquid ultraviolet curable resin into close contact with the substrate 2 in an uncured state. The ultraviolet curable resin is sufficiently filled in the concave portions having fine irregularities formed on the peripheral side surface of the roll plate 13. In this manufacturing process, the ultraviolet curable resin is cured by irradiation of ultraviolet rays in this state, and thereby the microprojection layer 3 is formed on the surface of the substrate 2. In this manufacturing process, the substrate 2 is peeled off from the roll plate 13 through the peeling roller 15 together with the cured ultraviolet curable resin. In the manufacturing process 10, the adhesive layer forming material according to the adhesive layer 4 is subsequently applied by the die 16, and then the adhesive layer 4 is formed through a process such as drying.

[Molding mold]
FIG. 3 is a perspective view showing the configuration of the roll plate 13. The roll plate 13 has a fine concavo-convex shape formed on the peripheral side surface of the base material, which is a cylindrical metal material, by repeating anodizing treatment and etching treatment, and the fine concavo-convex shape is formed on the substrate 2 as described above. It is shaped. For this reason, a columnar or cylindrical member in which a high-purity aluminum layer is provided at least on the peripheral side surface is used as the base material. More specifically, in this embodiment, a hollow stainless steel pipe is applied to the base material, and a high-purity aluminum layer is provided directly or via various intermediate layers. In addition, it may replace with a stainless steel pipe and may apply pipe materials, such as copper and aluminum. In the roll plate 13, fine holes are densely formed on the peripheral side surface of the base material by repeating the anodizing treatment and the etching treatment, and the fine holes are dug, and the diameter of the roll plate 13 increases as it approaches the opening. The concavo-convex shape is produced by gradually increasing the diameter of the fine holes. As a result, the roll plate 13 is densely formed with fine holes whose diameter gradually decreases in the depth direction, and the microprojection layer 3 of the adhesive film 1 gradually corresponds to the fine holes as it approaches the top. A fine concavo-convex shape is produced by a large number of small protrusions having a small diameter (so-called tapering).

[Anodic oxidation treatment, etching treatment]
FIG. 4 is a diagram showing a manufacturing process of the roll plate 13. In this manufacturing process, the peripheral side surface of the base material is made into a super mirror surface by an electrolytic composite polishing method that combines electrolytic elution action and abrasion action by abrasive grains (electrolytic polishing). Subsequently, in this step, aluminum is sputtered on the peripheral side surface of the base material to produce a high-purity aluminum layer. Subsequently, in this process, the base material is processed by alternately repeating the anodic oxidation processes A1,..., AN, and the etching processes E1,.

  In this manufacturing process, in the anodic oxidation steps A1,..., AN, a fine hole is produced on the peripheral side surface of the base material by an anodic oxidation method, and the produced fine hole is further dug. Here, in the anodic oxidation step, various methods applied to the anodic oxidation of aluminum can be widely applied, for example, when a carbon rod, a stainless steel plate, or the like is used for the negative electrode. Further, as the solution, various neutral and acid solutions can be used. More specifically, for example, a sulfuric acid aqueous solution, an oxalic acid aqueous solution, a phosphoric acid aqueous solution and the like can be used. In the manufacturing steps A1,..., AN, the fine holes are formed in shapes corresponding to the target depth and the shape of the fine protrusions, respectively, by managing the liquid temperature, the applied voltage, the time for anodization, and the like.

  In the subsequent etching process E1,..., EN, the mold is immersed in an etching solution, the hole diameter of the fine hole produced and dug in the anodizing process A1,. These fine holes are shaped so that the hole diameter becomes smaller and smoother. As the etching solution, various etching solutions that are applied to this type of treatment can be widely applied. More specifically, for example, a sulfuric acid aqueous solution, an oxalic acid aqueous solution, a phosphoric acid aqueous solution, or the like can be used. As a result, in this manufacturing process, the anodizing process and the etching process are alternately performed a plurality of times, so that fine holes for forming are formed on the peripheral side surface of the base material.

  In this embodiment, by repeating the anodic oxidation process and the etching process in this way, the micro hole is dug while expanding the hole diameter, and thereby the micro hole for forming the minute projection is produced.

〔Experimental result〕
FIG. 5 is a diagram showing a test result of the adhesive strength between the pressure-sensitive adhesive layer 4 and the substrate 2. Here, sample 1 is a microprojection layer 3 in which a TAC film having a thickness of 80 μm is applied to base material 2 and an acrylic acrylate UV curable resin is applied with a dry film thickness of 6 μm. The height of the fine protrusions on the fine protrusion layer 3 was 0.1 to 0.2 μm. The average interval between the microprotrusions was about 100 nm.

  Sample 2 was prepared in the same manner as Sample 1, except that the average distance between the microprojections was set to about 200 nm by changing the mold used for the forming process. A comparative example is a case where the microprojection layer 3 is not provided on the substrate 2.

  This test was to confirm the effect of fixing the adhesive layer to the microprotrusions. By attaching cello tape to Sample 1, Sample 2 and Comparative Example and measuring the peel strength, the adhesion of this cello tape (registered trademark) was confirmed. The adhesive layer was regarded as an adhesive layer 4, and the peel strength between the substrate and the adhesive layer was measured. The test was a 180 degree peel test based on JIS Z0237, and was performed using a test apparatus RTF-1150 Tensilon RT. The peeling speed was 300 mm / min, and a Nichiban cellophane tape was attached to Sample 1, Sample 2, and Comparative Example with a 2 kg roller, and then left for 30 minutes for measurement.

  According to this test result, it can be seen that the peel strength between the base material and the adhesive layer is increased by providing the microprojection layer. Note that “remaining adhesive residue” in the remarks indicates an adhesive residue remaining on the minute protrusion layer side.

  FIG. 6 shows the result of measuring the adhesive force by further creating an adhesive layer 4 made of an ultraviolet curable resin in Sample 1 and the comparative example and attaching the adhesive layer 4 to an adherend. In addition, the peeling force concerning the adhesive layer of a cellophane tape was also measured as a comparative example. The adherend is PET 100 μm (the untreated surface side of A4100 manufactured by Toyobo Co., Ltd.). Similar to the measurement results of FIG. 5, the test was a 180 degree peel test in accordance with JIS Z0237, and was performed using a test apparatus RTF-1150 Tensilon RT. The peeling speed is 300 mm / min, and the measurement results obtained by attaching the sample 1 and the comparative example to the adherend using a 2 kg roller and leaving them for 30 minutes are shown initially. After UV is the peel strength after UV irradiation. The adhesive layer thickness of 1.4 μm is a value obtained by multiplying the wet thickness of 9.1 μm formed by the wire bar # 4 by the solid content ratio of 15%, and the adhesive layer thickness of 6.8 μm is an applicator. It is a numerical value obtained by multiplying the formed wet thickness of 37.5 μm by a solid content ratio of 18%.

  When the thickness of the pressure-sensitive adhesive layer 4 is thicker than the range of the present invention, the pressure-sensitive adhesive layer 4 has a higher adhesive force when the fine protrusion layer 3 is not provided (comparative example). On the other hand, when the thickness of the pressure-sensitive adhesive layer 4 is 1 μm, the sample has a larger adhesive force. Thus, it can be seen that by providing the microprojection layer 3, the adhesive force between the upper adhesive layer and the adhesive target can be improved. Although the reason for this is not clear, as shown in FIG. 1, it is estimated that the surface of the pressure-sensitive adhesive layer 4 has formed a new uneven surface 5 due to the influence of the unevenness of the microprojections 3.

  According to the above configuration, the peel strength can be increased and the peel strength can be increased by forming the adhesive layer on the surface of the substrate through the microprojection layer formed by the close arrangement of the tapered microprojections according to the moth-eye structure. Subtle adjustments are possible.

[Other Embodiments]
The specific configuration suitable for the implementation of the present invention has been described in detail above. However, the present invention can be variously modified from the configuration of the above-described embodiment without departing from the spirit of the present invention, and further the conventional configuration. Can be combined.

  That is, in the above-described embodiment, the case where the number of repetitions of the anodizing treatment and the etching treatment is set to 3 (to 5) each is described, but the present invention is not limited to this, and the number of repetitions is set to other times. In addition, the present invention can be widely applied to the case where the process is repeated a plurality of times and the final process is anodizing.

  In the above-described embodiment, the case where the receiving layer is formed on the base material has been described. However, the present invention is not limited to this, and the present invention is not limited to this. Can be widely applied.

  In the above-described embodiment, the case where the microprojection layer is created by the shaping process using the roll plate has been described. However, the present invention is not limited to this, and the microprojection layer may be created by a single wafer process.

DESCRIPTION OF SYMBOLS 1 Adhesive film 2 Base material 3 Microprotrusion layer 4 Adhesive layer 10 Manufacturing process 12, 16 Die 13 Roll plate 14, 15 Roller

Claims (2)

A substrate provided with a microprojection layer on which at least one side a tapered microprojection having a height of 100 nm or more and 300 nm or less is closely formed at an interval of 50 nm or more and 500 nm or less;
An adhesive film comprising an adhesive layer formed on the microprojection layer,
The pressure-sensitive adhesive layer is a pressure-sensitive adhesive film having an average thickness of 100 nm to 2000 nm. A step of creating a microprojection layer that forms a microprojection layer by closely creating a tapered microprojection on the surface on one side of the substrate;
A pressure-sensitive adhesive layer creating step for creating a pressure-sensitive adhesive layer on the microprojection layer,
The step of creating the microprojections includes
A process for creating a mold for molding that creates a mold for molding having micro holes created by repetition of anodizing and etching;
A pressure-sensitive adhesive film manufacturing method comprising: a molding processing step of creating the microprojection layer by molding processing using the molding die.

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