JP2016188344A - Release film, adhesive sheet, and method for producing release film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form unevenness having a high roughed effect and a random pattern on a release surface of a release film with an easy method.SOLUTION: A release film 10 is a release film having a substrate 11, a resin layer 12 provided on the substrate 11, and a release agent layer 13 provided on a surface in an opposite side to the substrate 11 of the resin layer 12, where the resin layer 12 is formed by curing a curable material containing an alkylated melamine resin (A) having an alkyl group having 4-18 carbon atoms as a main component, and unevenness is provided on the surface 13A of the release agent layer 13 so that a ridge line with an average valley height of 0.5 μm or more is present thereon.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a release film, an adhesive sheet to which the release film is applied, and a method for producing the release film.

  Conventionally, a pressure-sensitive adhesive sheet that includes a base material and a pressure-sensitive adhesive layer provided on one surface of the base material and has fine irregularities formed on the surface of the pressure-sensitive adhesive layer is known. For example, Patent Document 1 discloses that the concavo-convex shape includes a plurality of grooves, and these grooves communicate with the outside when the adhesive sheet is bonded to the adherend. The pressure-sensitive adhesive sheet having such a concavo-convex shape makes it difficult for air trapped between the adherend and the pressure-sensitive adhesive sheet because air trapped on the adherend easily escapes to the outside. Moreover, since the adhesion area with respect to the adherend of an adhesive sheet becomes small, it becomes possible to make re-peelability (rework property) favorable.

  In Patent Document 1, the uneven shape on the surface of the pressure-sensitive adhesive layer is formed by laminating the pressure-sensitive adhesive layer on the release surface of the release liner that has been made uneven. Further, it is shown that the uneven shape of the release liner is a specific repeating pattern such as a grid pattern.

Japanese Patent No. 3708471

  However, as in Patent Document 1, if the unevenness of the release liner is a specific repeating pattern, the pattern is also transferred to the adhesive sheet, so that the unevenness is conspicuous in the adhesive sheet and the aesthetic appearance may be impaired. In order not to impair the beauty of the pressure-sensitive adhesive sheet, for example, it is conceivable to make the unevenness of the release liner fine and random. However, Patent Document 1 does not disclose a method for forming such an uneven surface.

  The present invention has been made in view of the above problems, and the object of the present invention is to form a random uneven surface sufficiently roughened on the release surface of the release film by a simple method, Thereby, for example, it is providing the peeling film which can make rework property favorable, without impairing the beauty | look of the adhesive sheet etc. in which an uneven surface is transcribe | transferred.

As a result of intensive studies, the present inventors applied a curable material containing a specific alkylated melamine resin as a main component to the base material and cured it, and the surface of the cured film has a high roughening effect. And it discovered that the unevenness | corrugation of a random pattern was formed. And it discovered that the said subject could be solved by forming a release agent layer in the cured film surface with the unevenness | corrugation, and completed the following this invention. That is, the present invention provides the following (1) to (13).
(1) A release film comprising a substrate, a resin layer provided on the substrate, and a release agent layer provided on the surface of the resin layer opposite to the substrate,
The resin layer is formed by curing a curable material containing, as a main component, an alkylated melamine resin (A) having an alkyl group having 4 to 18 carbon atoms,
A release film in which irregularities are provided on the surface of the release agent layer such that a ridge line having an average peak height of 0.5 μm or more exists.
(2) The release film according to (1), wherein a ridge line having a ratio (L / W) of length (L) to width (W) of 10 or more exists.
(3) In the above (1) or (2), the surface of the release agent layer has an arithmetic average roughness Ra of 0.1 to 5 μm and a maximum peak height Rp of 0.3 to 10 μm in the roughness curve. The release film as described.
(4) The release film according to any one of (1) to (3), wherein an average width of the ridgeline is 5 to 100 μm.
(5) The release film according to any one of (1) to (4), wherein an average peak height of the ridge line is 25 μm or less.
(6) The release film according to any one of (1) to (5), wherein the curable material further includes an acid catalyst (B).
(7) The release film according to (6), wherein 0.7 to 7.0 parts by mass of the acid catalyst (B) is blended with respect to 100 parts by mass of the alkylated melamine resin (A).
(8) The release film according to any one of (1) to (7), wherein the resin layer has a thickness of 3 to 30 μm.
(9) The release agent layer is selected from a silicone resin release agent, an alkyd resin release agent, an olefin resin release agent, an acrylic release agent, a long-chain alkyl group-containing compound release agent, and a rubber release agent. The release film according to any one of (1) to (8), comprising at least one release agent.
(10) The release film according to any one of (1) to (9), wherein the release agent layer has a thickness of 25 to 1000 nm.
(11) The release film according to any one of (1) to (10), wherein a pressure-sensitive adhesive layer is disposed on the surface of the release agent layer, and irregularities on the surface of the release agent layer are transferred to the pressure-sensitive adhesive layer. .
(12) The release film according to any one of (1) to (11), an adhesive layer provided on the surface of the release agent layer of the release film, and further provided on the adhesive layer. An adhesive sheet comprising an adhesive sheet substrate.
(13) By applying a curable material containing an alkylated melamine resin (A) having an alkyl group having 4 to 18 carbon atoms as a main component to a base material and curing the curable material, unevenness is formed on the surface. The provided resin layer is formed, and further, a release agent is applied to the resin layer to form a release agent layer having irregularities provided on the surface so that a ridge line having an average peak height of 0.5 μm or more exists. A method for producing a release film.

  According to the present invention, it is possible to form unevenness having a high roughening effect and a random pattern on the release surface of the release film by a simple method. Therefore, the pressure-sensitive adhesive sheet to which the unevenness of the release film is transferred has good reworkability without impairing the aesthetic appearance.

It is typical sectional drawing which shows one Embodiment of a peeling film. In the peeling film which concerns on one Embodiment of this invention, it observes the surface of a releasing agent layer with a laser microscope, performs three-dimensional image processing, and is a figure which shows typically the image obtained by the three-dimensional image processing. It is a schematic diagram which shows the width | variety and length of a ridgeline. The cross section of the release agent layer on the IV-IV line in FIG. 2 is shown. It is a typical sectional view showing one embodiment of an adhesive sheet. The surface of the release agent layer of the release film obtained in Example 1 is observed with a laser microscope, three-dimensional image processing is performed, and image data obtained by the three-dimensional image processing is shown.

Hereinafter, the present invention will be described in more detail using embodiments.
As shown in FIG. 1, a release film 10 according to an embodiment of the present invention includes a base material 11, a resin layer 12 provided on one side of the base material 11, and a surface of the resin layer 12 opposite to the base material 11. And a release agent layer 13 provided on (surface 12A). Unevenness is randomly formed on the surface 12A of the resin layer 12 so that a ridgeline exists.
The release agent layer 13 is formed along the unevenness of the surface 12A of the resin layer 12, and the surface 13A of the release agent layer 13 has unevenness corresponding to the uneven shape of the surface 12A. Therefore, the ridgeline 15 (see FIG. 2) also exists on the unevenness of the surface 13A of the release agent layer.
Note that the ridge line refers to an elongated protrusion that is described in detail later.

Hereinafter, each member of the release film of the present invention will be described in more detail.
[Base material]
The base material 11 can be a general-purpose base material and is not particularly limited. For example, polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins such as polypropylene and polymethylpentene, polycarbonates, polyvinyl acetate, Resin films composed of various resins such as polysulfone, polyether ether ketone, polyether sulfone, polyphenylene sulfide, polyether imide, polyimide, polyamide, and acrylic resin can be used. Among these, polyester is preferable and polyethylene terephthalate is more preferable from the viewpoint of ease of processing, durability, heat resistance, cost, and the like. These may be a single layer, or may be a multilayer of two or more of the same or different types.
Although the thickness of the base material 11 is not specifically limited, Usually, 10-300 micrometers, Preferably it is about 15-200 micrometers.

[Resin layer]
The resin layer 12 is formed by curing a curable material containing, as a main component, an alkylated melamine resin having an alkyl group having 4 to 18 carbon atoms (hereinafter also simply referred to as an alkylated melamine resin (A)). In the present invention, by forming the resin layer 12 with the alkylated melamine resin (A) having an alkyl group having a relatively large number of carbon atoms, the surface 12A of the resin layer 12 is a random and rough surface so that a ridgeline exists. Concavities and convexities having a high effect are provided.

  In this way, when a curable material containing a specific alkylated melamine resin (A) is cured, the principle that irregularities are randomly formed on the surface 12A of the resin layer so that a ridge line exists is not clear, but Is estimated as follows. That is, since the crosslinking of the melamine resin proceeds by the elimination of alcohol or water, the alkylation ratio between the polymer and the low molecule deviates depending on the progress of the crosslinking. And, due to the large number of carbon atoms in the alkyl group, the compatibility between the component having a high molecular weight and the component having a high molecular weight that has been delayed is lowered, and thus the film thickness after drying is different. It is estimated that

The carbon number of the alkyl group contained in the alkylated melamine resin (A) affects the uneven shape formed on the surface of the resin layer. Specifically, the surface of the resin layer is increased by increasing the carbon number of the alkyl group. The unevenness difference can be increased. Therefore, when the carbon number of the alkyl group is as small as less than 4, a ridge line cannot be formed on the surface of the resin layer, the unevenness difference is reduced, and it becomes difficult to exhibit a high roughening effect. On the other hand, when the number of carbon atoms of the alkyl group exceeds 18, the alkylated melamine resin (A) itself is difficult to produce, and further, the alkylated melamine resin (A) may be difficult to crosslink. .
From these viewpoints, the alkyl group contained in the alkylated melamine resin (A) preferably has 4 to 12 carbon atoms, and more preferably 6 to 10 carbon atoms. The alkyl group may be linear or branched.
The alkylated melamine resin (A) is obtained by etherifying a part or all of the methylol group in the methylol melamine resin with an alkyl monoalcohol, specifically, a normal butylated melamine resin, an isobutylated melamine resin, Examples thereof include normal octylated melamine resins.

  In addition, the inclusion of the alkylated melamine resin (A) as a main component means that the curable material is an alkylated melamine resin (A) to the extent that predetermined unevenness can be formed on the surface of the resin layer by crosslinking of the alkylated melamine resin (A). In general, the content of the alkylated melamine resin (A) in the curable material is 50% by mass or more based on the total amount of nonvolatile components of the curable material. The content of the alkylated melamine resin (A) is preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more with respect to the total amount of the nonvolatile components. In this specification, the total amount of non-volatile components of the curable material refers to an amount obtained by removing volatile components such as a solvent that is volatilized in a manufacturing process such as a curing step from the curable material.

The curable material preferably contains an acid catalyst (B) in addition to the alkylated melamine resin (A). When the curable material contains the acid catalyst (B), it is possible to easily advance the crosslinking of the alkylated melamine resin (A). Moreover, it is also possible to adjust the level difference of the unevenness | corrugation formed in the resin layer surface by adjusting the compounding quantity of an acid catalyst (B).
Specifically, in the curable material, the acid catalyst (B) is preferably blended in an amount of 0.7 to 7.0 parts by mass with respect to 100 parts by mass of the alkylated melamine resin (A).
By setting the blending amount of the acid catalyst to be equal to or more than the above lower limit, curing proceeds appropriately, and problems such as poor curing are prevented. On the other hand, when the blending amount is not more than the above upper limit value, it is possible to prevent the curing rate from being increased, and a portion where the progress of the crosslinking is different is generated, so that the uneven shape is easily provided. From the viewpoint of increasing the level difference of the unevenness and enhancing the roughening effect, the amount of the acid catalyst (B) is more preferably 0.8 to 5.0 parts by mass, and 0.8 to More preferably, it is 2.5 parts by mass.

Specific examples of the acid catalyst (B) include sulfonic acids such as paratoluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenedisulfonic acid and methanesulfonic acid, and acidic substances such as mineral acids represented by hydrochloric acid and sulfuric acid. Of these, sulfonic acid is preferable, and paratoluenesulfonic acid is more preferable.
The acid catalyst (B) may be mixed with an amine in advance and then blended with the curable material. Here, examples of the amine include tertiary amine compounds such as triethylamine, tripropylamine, and tributylamine. When the acid catalyst (B) is mixed with an amine, the acid catalyst (B) is mixed with the curable material as an amine salt. The amount of the acid catalyst (B) is an acidic substance itself before becoming an amine salt. Means the amount. In addition, when the acid catalyst (B) is an amine salt, the curing reaction rate is prevented from becoming too fast, and it becomes easy to form an uneven shape having a high roughening effect.

Moreover, unless the objective of this invention is impaired, a curable material may also contain components other than the said (A) (B) component, for example, may contain resin components other than (A) component. Further, the curable material may contain various additives, and may contain, for example, an antioxidant, an ultraviolet absorber, a pigment, a surface conditioner, and the like.
However, it is preferable that the curable material does not substantially contain a particulate filler. Here, “substantially containing no particulate filler” means that the particulate filler may be contained to the extent of impurities, specifically, less than about 1 mass% of the total amount of nonvolatile components of the curable material. If so, it may be contained. However, it is more preferable that the curable material does not contain a particulate filler in order to further prevent contamination by foreign substances. The particulate filler means one having an average particle diameter measured by a laser diffraction / scattering measurement method of 0.1 μm or more.

The uneven shape formed on the surface of the resin layer (that is, the release agent layer) can also be adjusted by changing the thickness of the resin layer. For example, the uneven shape can be increased by increasing the thickness of the resin layer. It becomes easy to increase the roughening effect by increasing the difference in height of the surface. Specifically, the thickness of the resin layer is preferably 3 to 30 μm, and more preferably 5 to 28 μm. The thickness of the resin layer is obtained by measuring with a contact-type film thickness meter. By making the thickness of the resin layer not less than the lower limit value, the roughening effect can be sufficiently enhanced. Moreover, it becomes difficult to produce the increase in a residual solvent, the sclerosis | hardenability defect inside a coating film, etc. by setting it as an upper limit or less.
The thickness of the resin layer can be adjusted by adjusting the concentration of the non-volatile component of the coating solution described later or by appropriately changing the coating method.
In the release film, another layer may be provided between the resin layer and the substrate. For example, a primer layer may be provided in order to improve the adhesion between the resin layer and the substrate.

[Release layer]
The release agent layer 13 is composed of a release agent. The release agent layer 13 is formed along the uneven shape of the surface 12A of the resin layer 12, and the surface 13A of the release agent layer 13 has unevenness corresponding to the uneven shape of the surface 12A. That is, similar to the surface 12A of the resin layer 12, the surface 13A of the release agent layer 13 is provided with irregularities having a random and high roughening effect, and the irregularities have a predetermined average height as described later. There is a ridge line 15 (see FIG. 2) having a thickness.

  Examples of the release agent constituting the release agent layer 13 include non-silicone resin-based release agents such as alkyd resin-based, olefin resin-based, acrylic-based, long-chain alkyl group-containing compound-based rubbers, as well as silicone resin-based release agents. Agents.

  The silicone resin release agent includes a solvent type and a solventless type. Since the solvent-type silicone resin is diluted with a solvent to form a coating solution, it can be widely used from a high molecular weight (that is, high viscosity) polymer to a low viscosity low molecular weight polymer (oligomer). Therefore, it is easy to control the peelability as compared with the solventless type, and it is easy to design in accordance with the required performance (quality). Examples of the silicone resin release agent include addition reaction type, condensation reaction type, ultraviolet curable type, and electron beam curable type. The addition reaction type silicone resin is highly reactive and excellent in productivity. Compared to the condensation reaction type, the addition reaction type silicone resin has advantages such as a small change in peel force after production and no cure shrinkage. It is preferable to use it as a release agent.

There is no restriction | limiting in particular as an addition reaction type silicone resin, A various thing can be used. For example, what is conventionally used as a conventional thermosetting addition reaction type silicone resin release agent can be used. Examples of the addition reaction type silicone resin include those having an electrophilic group such as an alkenyl group such as a vinyl group or a hydrosilyl group as a functional group in the molecule, and examples of the addition reaction type silicone resin that can be easily cured. In addition, polydimethylsiloxane having such a functional group, or those obtained by substituting a part or all of the methyl group of polydimethylsiloxane with an aromatic functional group such as a phenyl group can be used.
If necessary, silica, silicone resin, antistatic agent, dye, pigment and other additives may be added to the silicone resin release agent.

After the silicone resin release agent is applied, the coating film may be cured by heat treatment in an oven of a coating machine, or after heat treatment, ultraviolet irradiation may be used in combination.
In addition, when using ultraviolet irradiation together for hardening of a coating film, it is desirable to add a photoinitiator to a peeling agent. There is no restriction | limiting in particular as a photoinitiator, Arbitrary things can be suitably selected and used from what is conventionally used by the thing which generate | occur | produces a radical by irradiation of an ultraviolet-ray or an electron beam. Examples of the photoinitiator include benzoins, benzophenones, acetophenones, α-hydroxyketones, α-aminoketones, α-diketones, α-diketones dialkylacetals, anthraquinones, thioxanthones, and the like.

  As the olefin resin release agent, a crystalline olefin resin is used. As this crystalline olefin resin, polyethylene, crystalline polypropylene resin, and the like are suitable. Examples of polyethylene include high density polyethylene, low density polyethylene, and linear low density polyethylene. Examples of the crystalline polypropylene resin include a propylene homopolymer having an isotactic structure or a syndiotactic structure, and a propylene-α-olefin copolymer. These crystalline olefin resins may be used alone or in combination of two or more.

  As the acrylic release agent, an acrylic resin having a crosslinked structure is generally used. The acrylic resin may be a modified product such as a long-chain alkyl-modified acrylic resin or a silicone-modified acrylic resin.

  Examples of the long-chain alkyl group-containing compound-based release agent include, for example, polyvinyl carbamate obtained by reacting a polyvinyl alcohol polymer with a long-chain alkyl isocyanate having 8 to 30 carbon atoms, or polyethyleneimine having 8 to 30 carbon atoms. An alkylurea derivative obtained by reacting a long-chain alkyl isocyanate is used.

Examples of the rubber release agent include natural rubber resins and synthetic rubber resins such as butadiene rubber, isoprene rubber, styrene-butadiene rubber, methyl methacrylate-butadiene rubber, and acrylonitrile-butadiene rubber.
Each of the above release agents may further contain components such as a curing agent and a catalyst.

   The thickness of the release agent layer 13 is not particularly limited, but is preferably 25 to 1000 nm, and more preferably 40 to 500 nm. By setting the thickness to 25 nm or more, the function as a peeling surface can be sufficiently exhibited. Moreover, the unevenness | corrugation which maintained the uneven | corrugated shape of the resin layer 12 almost can be formed in the surface of the releasing agent layer 13 by making thickness into 1000 nm or less. The thickness of the release agent layer is obtained by measuring with a contact-type film thickness meter.

FIG. 2 is a diagram schematically showing an image obtained by observing the surface 13A of the release agent layer 13 with a laser microscope, performing three-dimensional image processing, and the three-dimensional image processing.
In the present invention, the surface 13A of the release agent layer 13 is provided with irregularities so that the ridge line 15 having an average peak height of 0.5 μm or more exists. Here, the “ridge line” refers to an elongated projection, and specifically, a projection having a peak height of 50% or more of the maximum peak height in the observed image 1 cm ² (1 cm × 1 cm) is the same. This means that the ridgeline width (W) is continuous for a length of 3 times or more of the five-point average value.
Further, as shown in FIG. 3, it is preferable that the ridge line 15 has a ratio (L / W ratio) of the length (L) to the width (W) of 10 or more. In addition, the measuring method of peak height, width (W), and L / W ratio is mentioned later. In FIG. 2, a contour line having a height of 0.5 μm is drawn with a solid line, and at least an elongated part of the part surrounded by the solid line is a ridge line 15.
Further, when the surface 13A of the release agent layer 13 is observed at 1 cm ² , one or more ridge lines 15 may be present, but a plurality of ridge lines 15 are preferable, and a plurality of ridge lines having an L / W ratio of 10 or more exist. More preferably. By the presence of a plurality of ridge lines 15 having a large L / W ratio, the pattern formed on the surface 13A of the release agent layer tends to be random and unique. According to such a configuration, elongated grooves are randomly formed in a member to be peeled such as an adhesive layer described later.

  As shown in FIG. 2, the ridge line 15 is usually curved or further branched in a part of the surface 13A of the release agent layer in parallel with two or more rows. Thus, since the ridgeline 15 is irregularly arranged while a part thereof is parallel, the surface 13A of the release agent layer exhibits a random stripe pattern. Further, there are valleys 16 between the parallel ridge lines 15, and the surface 13 </ b> A of the release agent layer exhibits a unique uneven shape due to the ridge lines 15 and the valleys 16. In addition, the convex part which does not usually become the ridgeline 15 also exists in the surface 13A of the release agent layer.

As described above, the ridgeline 15 formed on the surface 13A of the release agent layer preferably has an average peak height of 0.5 μm or more and 25 μm or less. When the average peak height is less than 0.5 μm, the unevenness of the unevenness on the surface 13A of the release agent layer becomes small, and a roughening effect cannot be sufficiently obtained. Moreover, formation of the ridgeline 15 becomes easy by setting it as 25 micrometers or less.
From the above viewpoint, the average peak height of the ridge line is more preferably 1 to 20 μm, and further preferably 2 to 18 μm.

  Moreover, it is preferable that the average width of the ridgeline 15 is 5-100 micrometers, 10-80 micrometers is more preferable, 15-70 micrometers is more preferable. When the average width of the ridge line is in the predetermined range as described above, it is easy to enhance the roughening effect and to form a unique shape on the surface of the release agent layer.

In the present specification, the peak height (H) means that a three-dimensional image observed with a laser microscope is processed, and as shown in FIG. Draw a straight line connecting the valley bottoms 15B, 15B on both sides of the mountain top 15A, and the length of the perpendicular line perpendicular to the mountain top 15A. Measure the mountain height (H) at five points and calculate the average value as the average mountain height. Calculate as
Further, the width (W) of the ridge line is a cross section taken in the same manner as the measurement of the average peak height, and as shown in FIG. 4, the interval between the valley bottoms 15B and 15B adjacent to the arbitrary ridge line 15 is measured. Yes, the average width of the ridge line is obtained by measuring the width (W) of the ridge line at five points and calculating the average value.

The ratio of the length (L) to the width (W) (L / W ratio) is measured as follows.
First, the length (L) of the ridge line is selected as a long ridge line in an observation image of 1 cm ² (1 cm × 1 cm) observed with a laser microscope, and as shown in FIG. The position where the peak height is 70% from the peak height is defined as the end in the length direction of the ridge line, and the distance from the end to the other end is measured along the ridge line. The L / W ratio is a ratio between the measured length (L) and the width (W) of the ridgeline that was the measurement target of the length (L). Note that the width (W) of the ridge line is an average value of five points on the ridge line.
In addition, when the ridgeline was branched, the edge part was selected so that the ridgeline distance might become the maximum, and the length of the ridgeline was measured. Further, when one or both ends of the ridge line are not on the observation image, the length of the ridge line on the four sides of the observation image is assumed to be the end of the ridge line, and the length is measured. The L / W ratio is calculated based on the length.

The surface 13A of the release agent layer preferably has an arithmetic average roughness Ra of 0.1 to 5 μm and a maximum peak height Rp of 0.3 to 10 μm in the roughness curve. When Ra and Rp are in the above ranges, the unevenness difference of the release agent layer 13 is increased, and the roughening effect is easily enhanced. The arithmetic average roughness Ra is more preferably 0.2 to 4 μm, still more preferably 0.5 to 3.5 μm, and the maximum peak height Rp in the roughness curve is more preferably 0.5 to 9 μm. And more preferably 1 to 8 μm.
In addition, these arithmetic mean roughness Ra and maximum peak height Rp are measured based on JISB0601-2001 using the contact-type surface roughness meter.

[Method for producing release film]
In the release film of the present invention, first, the above-described curable material is applied to a base material, and the curable material is cured to form a resin layer having unevenness on the surface, and then the resin layer It is manufactured by applying a release agent to form a release agent layer.
Here, the curable material is preferably diluted with a solvent and applied to the substrate. As the solvent used, it is only necessary to dissolve or disperse the curable material, and toluene, xylene, methyl ethyl ketone, cellosolve acetate, methanol, ethanol, isopropyl alcohol, n-butanol, cyclohexanone and the like are used. These may be used alone or in combination of two or more.

The curable material is applied by, for example, a gravure coating method, a bar coating method, a spray coating method, a spin coating method, an air knife coating method, a roll coating method, a blade coating method, a gate roll coating method, or a die coating method. be able to.
Moreover, the curable material apply | coated on the base material is hardened | cured by heating, for example, it is preferable to be dried and hardened by heating at 70-170 degreeC for about 1-10 minutes.

  The release agent layer can be formed by applying the release agent on the surface of the resin layer after diluting the release agent with a diluent as necessary, followed by drying and curing. As a coating method, for example, a gravure coating method, a bar coating method, a spray coating method, a spin coating method, a knife coating method, a roll coating method, a die coating method, or the like can be used.

  The release film 10 of the present invention is provided with a releasability on the surface 13A and is used for various applications, but can be used in the same manner as a conventional release film. . For example, the release film 10 is formed by applying, casting, laminating, sticking, or the like to various materials on the surface 13A of the release agent layer, and a member made of the material coated, cast, laminated, pasted, etc. ( In general, this member is also appropriately peeled from the “member to be peeled”. Normally, the shape of the surface 13A of the release agent layer is transferred to the surface of the member to be peeled to form an uneven surface.

Since the uneven shape of the surface 13A of the release film is randomly arranged, random unevenness is also transferred to the surface of the member to be peeled. The unevenness formed on the surface 13A of the release film or transferred to the member to be peeled is so fine that it cannot be visually detected. Furthermore, such irregularities are not conspicuous by being randomly arranged, and the appearance of the release film and the member to be peeled is prevented from being impaired.
Note that, as described above, the ridge line 15 is present on the surface 13A of the release agent layer. However, when the ridge line 15 is transferred to the member to be peeled, it becomes a groove arranged at random.

[Adhesive sheet]
In this invention, it is preferable that the said to-be-peeled member is an adhesive layer, and specifically, it is preferable that the peeling film 10 of this invention is applied to an adhesive sheet as shown in FIG. Hereinafter, the adhesive sheet to which the release film of the present invention is applied will be described.
As shown in FIG. 5, the adhesive sheet 20 is further provided on the release film 10, the adhesive layer 21 provided on the surface 13 </ b> A of the release agent layer 13 of the release film 10, and the adhesive layer 21. And an adhesive sheet substrate 22. And as for the adhesive surface 21A of the adhesive layer 21 stuck on the surface 13A of the release agent layer 13, the uneven | corrugated shape of the release agent layer 13 is transcribe | transferred, and a fine unevenness | corrugation is formed.

  The pressure-sensitive adhesive sheet 20 is peeled off the laminate of the pressure-sensitive adhesive layer 21 and the pressure-sensitive adhesive sheet base material 22 from the release film 10 and attached to the adherend via the pressure-sensitive adhesive surface 21A. At this time, the adhesive surface 21A has an uneven surface, so that the adhesion area becomes small, so that the reworkability is improved. That is, the adhesive sheet 20 can be easily reapplied even after it is once attached to the adherend.

  As the adhesive sheet base material 22, a general-purpose base material can be used and there is no particular limitation, but various resin films can be used. The resin film can be appropriately selected from those listed as resin films that can be used for the substrate 11 and can be used. The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer is not particularly limited, and examples thereof include acrylic pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, polyester-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, and polyolefin-based pressure-sensitive adhesives. However, the present invention is not limited to these, and any one can be appropriately selected and used.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not restrict | limited by these examples.

[Thickness of resin layer and release agent layer]
The thickness of the resin layer and the release agent layer was an average value of five measurement points measured with a contact-type film thickness meter (manufactured by Techlock Co., Ltd., product name “constant pressure thickness measuring instrument PG-02”). .
[Surface roughness]
The arithmetic mean roughness Ra of the release agent layer surface of the release film and the maximum peak height Rp in the roughness curve are measured using a contact type surface roughness meter (product name “SV3000S4” manufactured by Mitutoyo Corporation) and JIS B0601-2001. Measured according to

[Evaluation of uneven shape]
Using a laser microscope (shape measurement laser microscope VK-9700, manufactured by Keyence Corporation), the surface of the release agent layer of the release film was observed for 1 cm ² (1 cm × 1 cm), and the method described in the specification According to the above, the average peak height of the ridgeline is measured, it is determined whether or not the average peak height of the ridgeline is less than 0.5 μm, and when the average peak height is less than 0.5 μm, it is evaluated as “smooth surface”. did.
Moreover, although there was an unevenness | corrugation whose average peak height was set to 0.5 micrometer or more, when a 1 cm < ² > observation was carried out on the surface of a release agent layer, it was evaluated as "no ridgeline". On the other hand, those having an average mountain height of 0.5 μm or more and having ridge lines were evaluated as “with ridge lines”.
In addition, when there is no ridge line on the surface of the release agent layer of the release film, the average peak height and the average width are described in the specification except that the cross section is taken at an arbitrary position instead of being taken at a position perpendicular to the ridge line. Measured according to the method of
Further, according to the method described in the specification, it is determined whether or not there is a ridge line having an L / W ratio of 10 or more in an observation image of 1 cm ² , and if the average peak height is 0.5 μm or more, the average In addition to the peak height, the average width was also measured. The measurement results are shown in Table 1.
[Adhesion evaluation]
The release film layer surface of the release film and the CPP film are rubbed using a friction fastness tester (manufactured by Daiei Chemical Seiki Co., Ltd., product name “RT-200”) (load 1 kg, 30 reciprocations), filler or coating The presence or absence of layer dropping was visually evaluated.

[Reworkability]
Samples with a width of 25 mm of the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples were prepared and pasted once on soda glass with a 5 kg rubber roller, and the adhesive strength was measured immediately after pasting and 24 hours later. The adhesive strength was measured using “Precision Universal Testing Machine Autograph AG-IS” manufactured by Shimadzu Corporation and a 20N load cell “SLBL-20N” manufactured by the same company.
The adhesive strength immediately after pasting is 15 N / 25 mm or less and the adhesive strength after 24 hours is 20 N / 25 mm or more as an evaluation with excellent reworkability (Evaluation A), and the adhesive strength in other ranges is inferior to reworkability. It was set as evaluation (evaluation B).
[Appearance test]
Samples having a size of 50 mm × 50 mm were prepared from the pressure-sensitive adhesive sheets obtained in Examples and Comparative Examples. The sample was reciprocated once on a glass plate with a 5 kg rubber roller, and the substrate surface of the pressure-sensitive adhesive sheet was observed with the naked eye. The case where the unevenness | corrugation of an adhesive layer was not recognizable on the base-material surface was set to A, and the case where it can recognize was set to B.

[Example 1]
(Preparation of release film)
Octylated melamine resin (trade name “ATOM BOND RP-30”, manufactured by Sanba Laboratory, Inc., non-volatile component concentration: 30% by mass, solvent: toluene / xylene / methyl ethyl ketone / cellosolve acetate / n-butanol = 25 / 15/5/10/15 (mass ratio) mixed solvent) 100 parts by mass (non-volatile component standard), acid catalyst diluent (trade name “ATOM BOND CP catalyst”, manufactured by Miwa Laboratory Co., Ltd.); paratoluenesulfone A mixture of 55 parts by mass of acid (acid catalyst) with 15 parts by mass of triethylamine and 30 parts by mass of methanol; 55% by mass of non-volatile components was mixed so that the compounding amount of the acid catalyst was 0.9 parts by mass. Further, it is diluted with a solvent (a mixed solvent of toluene / methyl ethyl ketone = 6/4 (mass ratio)), and a curable material having a nonvolatile component concentration of 30% by mass is applied. To prepare a liquid. One side of a polyethylene terephthalate (PET) film (trade name “Diafoil T-100” manufactured by Mitsubishi Plastics, Inc.) having a thickness of 50 μm so that the film thickness after drying is 7 μm with the Meyer bar. It was coated on the surface and dried at 150 ° C. for 5 minutes to form a resin layer having a roughened surface and irregularities.
Next, 100 parts by mass of polydimethylsiloxane resin (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KS-847H”, non-volatile component concentration: 30% by mass, solvent: toluene) is added to platinum catalyst (manufactured by Shin-Etsu Chemical Co., Ltd., trade name). “CAT-PL-50T”, 2% by mass of non-volatile components, solvent: toluene) are mixed so that the amount of the catalyst is 0.07 parts by mass, and further a solvent (toluene / methyl ethyl ketone = 6/4 (mass ratio)) To obtain a release agent coating solution having a nonvolatile component concentration of 1.5% by mass. The prepared coating solution is applied on the roughened resin layer with a Meyer bar so that the film thickness after drying is 100 nm, and dried at 150 ° C. for 1 minute to form a release agent layer. A release film was obtained.
The surface of the release agent layer of the release film was observed with a laser microscope, and three-dimensional image processing was performed to obtain a processed image. In addition, although the obtained image is shown in FIG. 6, a light part is a part used as a convex part.

(Preparation of adhesive sheet)
An acrylic pressure-sensitive adhesive (manufactured by Toyochem, trade name “BPS-5127”, nonvolatile component concentration: 40% by mass, solvent: ethyl acetate / toluene = 55/5) is applied to the surface of the release agent layer of the obtained release film. The coating was applied so that the coating amount was 25 g / m ² and dried at 100 ° C. for 2 minutes to form an adhesive layer. Thereafter, the pressure-sensitive adhesive layer was bonded to a corona-treated surface of a 38 μm-thick void-containing polyester film (white) (“Chrisper G1211” manufactured by Toyobo Co., Ltd.) as a pressure-sensitive adhesive sheet base material to prepare a pressure-sensitive adhesive sheet.

[Example 2]
It implemented similarly to Example 1 except the point which applied the coating liquid so that the thickness of a resin layer might be 25 micrometers.

[Comparative Example 1]
Mixture of 80 parts by mass of bisphenol A type epoxy resin ester and 20 parts by mass of melamine resin (manufactured by Hitachi Chemical Co., Ltd., trade name “TA31-059D”, solid content concentration 50%, solvent: xylene / toluene / isobutanol = 18 / The solution of p-toluenesulfonic acid (solid content concentration: 50 mass%, solvent: methanol / isopropyl alcohol = 41.100) as an acid catalyst with respect to 100 mass parts of solid content of 16/16 (mass ratio) mixed solvent). 2 / 9.4 (mass ratio) mixed solvent) 2.5 parts by mass (solid content ratio) was added to prepare a resin composition solution. Then, 10% by mass of porous amorphous silica particles (trade name “Nip Seal SS-50B”, average particle diameter 1.7 μm, manufactured by Tosoh Silica Co., Ltd.) are added to the solution of the resin composition, and toluene / methyl ethyl ketone = A release agent layer forming solution was prepared by diluting with a mixed solvent of 30/70 (mass ratio). The prepared coating solution was applied on one side of a 50 μm thick polyethylene terephthalate (PET) film (trade name “Diafoil T-100”, manufactured by Mitsubishi Plastics, Inc.) with a Mayer bar, and at 150 ° C. for 5 minutes. The film was dried to obtain a release film having a release agent layer formed on the substrate. Then, the adhesive sheet was produced similarly to Example 1.

[Comparative Example 2]
By laminating polyethylene of 30 μm thickness on high-quality paper of 110 g / cm ² , forming a convex strip of a predetermined shape using an embossing roll on the polyethylene side, and further applying a silicone resin of 0.1 μm thickness A release sheet having a shape transfer surface was formed. The ridges had an inverted U shape with a cross section of 20 μm in height and 60 μm in width, and formed a lattice shape that was orthogonal at a pitch of 570 μm.
Instead of the release film of Example 1, an adhesive sheet was prepared in the same manner as in Example 1 except that the above release sheet was used.

  As in Examples 1 and 2 above, a resin layer is formed from a curable material containing an alkylated melamine resin (A) having an alkyl group having 4 to 18 carbon atoms as a main component, and a release agent layer is formed thereon. Forming a ridge line over the entire surface of the release agent layer, the average height and average width of the ridge line are relatively large, and it is possible to obtain a release film having a unique random uneven shape with a high roughening effect. did it. Moreover, in the adhesive sheet using the release film, the adhesive strength after 24 hours was moderately high, while the adhesive strength immediately after application was low, thereby improving the reworkability. Further, the unevenness transferred from the release film to the surface of the pressure-sensitive adhesive layer had a fine and random shape, so that it could not be visually recognized with the naked eye, and the appearance was not impaired.

  On the other hand, when the filler is blended in the resin layer as in Comparative Example 1, the surfaces of the resin layer and the release agent layer can be used without using the alkylated melamine resin (A) having an alkyl group having 4 to 18 carbon atoms. However, there was a problem that the filler was dropped. Further, no elongated ridgeline was seen, and the irregular surface could not be made into a unique shape. Further, as in Comparative Example 2, in the pressure-sensitive adhesive sheet using the release sheet in which the ridges are formed in a repetitive pattern, the unevenness on the surface of the base material was visible with the naked eye, so it is not suitable for applications requiring design properties. Met.

DESCRIPTION OF SYMBOLS 10 Release film 11 Base material 12 Resin layer 13 Release agent layer 15 Ridge line 16 Valley 20 Adhesive sheet 21 Adhesive layer 22 Adhesive sheet base material H Height difference L Length of ridge line W Width of ridge line

Claims (13)

A release film comprising a base material, a resin layer provided on the base material, and a release agent layer provided on the surface of the resin layer opposite to the base material,
The resin layer is formed by curing a curable material containing, as a main component, an alkylated melamine resin (A) having an alkyl group having 4 to 18 carbon atoms,
A release film in which irregularities are provided on the surface of the release agent layer such that a ridge line having an average peak height of 0.5 μm or more exists.   The release film according to claim 1, wherein a ridge line having a ratio (L / W) of the length (L) to the width (W) of 10 or more exists.   3. The release film according to claim 1, wherein the release agent layer surface has an arithmetic average roughness Ra of 0.1 to 5 μm and a maximum peak height Rp in a roughness curve of 0.3 to 10 μm.   The release film according to claim 1, wherein an average width of the ridge line is 5 to 100 μm.   The peeling film according to any one of claims 1 to 4, wherein an average peak height of the ridge line is 25 µm or less.   The release film according to claim 1, wherein the curable material further contains an acid catalyst (B).   The release film according to claim 6, wherein the acid catalyst (B) is blended in an amount of 0.7 to 7.0 parts by mass with respect to 100 parts by mass of the alkylated melamine resin (A).   The thickness of the said resin layer is 3-30 micrometers, The peeling film of any one of Claims 1-7.   The release agent layer is at least one selected from a silicone resin release agent, an alkyd resin release agent, an olefin resin release agent, an acrylic release agent, a long chain alkyl group-containing compound release agent, and a rubber release agent. The release film according to any one of claims 1 to 8, wherein the release film is composed of a seed release agent.   The release film according to any one of claims 1 to 9, wherein the release agent layer has a thickness of 25 to 1000 nm.   The peeling film of any one of Claims 1-10 which arrange | positions an adhesive layer on the surface of the said releasing agent layer, and transfers the unevenness | corrugation of the surface of the said releasing agent layer to the said adhesive layer.   The release film according to any one of claims 1 to 11, an adhesive layer provided on a surface of a release agent layer of the release film, and an adhesive sheet base further provided on the adhesive layer. A pressure-sensitive adhesive sheet comprising a material.   By applying a curable material containing an alkylated melamine resin (A) having a C 4-18 alkyl group as a main component to a base material and curing the curable material, irregularities were provided on the surface. Forming a resin layer, and further applying a release agent to the resin layer to form a release agent layer having unevenness provided on the surface so that a ridge line having an average peak height of 0.5 μm or more exists. Production method.