Release coating agent, release film, and method for producing the release film

Abstract

To provide a release coating agent which is applied to one surface of a film in a thickness direction, then dries for forming a release layer, and in which a part of a component of the release layer can be suppressed from moving to the other surface of the film in contact of the release layer to the other surface of the film in the thickness direction, a release film and a production method of the release film.SOLUTION: A release coating agent comprises: a hydroxyl group-containing acryl resin; melamine resin; and a one-terminal modified silicon oil. A release film 1 comprises: a substrate film 2; and a release layer 3 formed of a coated film 30 of the release coating agent, in this order toward one side of a thickness direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a release coating, a release film, and a method for producing a release film. [Background technology]

[0002] It is known that a resin composition for a release film is applied to the surface of a base film to impart release properties to the surface of the base film. That is, a coating of the resin composition for a release film is disposed on the surface of the base film as a release layer. This results in a release film in which the base film and the release layer are disposed in this order on one side in the thickness direction.

[0003] For example, a resin composition for a release film has been proposed that contains a hydroxyl group-containing acrylic resin, a melamine resin, and a dual-end-modified silicone oil whose both ends are modified with hydroxyl groups (see Patent Document 1 below).

[0004] A functional layer is disposed on the back surface of the base film in the release film. The functional layer includes an adhesive layer. A functional film (adhesive film) including the release layer, the base film, and the functional layer (adhesive layer) is produced. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2020-189945 Summary of the Invention [Problem to be solved by the invention]

[0006] For industrial production reasons, the release film is long and wound into a roll. At that time, the release layer comes into contact with the back surface of the base film. In Patent Document 1, part of the components of the release layer (part of the resin composition for the release film) migrates to the back surface of the base film, which causes a problem in that the functional layer cannot be uniformly arranged on the back surface of the base film.

[0007] The present invention provides a release coating agent, a release film, and a method for producing a release film, which can be applied to one side of a film in the thickness direction and dried to form a release layer, and which can prevent some of the components of the release layer from migrating to the other side of the film when the release layer comes into contact with the other side of the film in the thickness direction. [Means for solving the problem]

[0008] The present invention (1) includes a release coating agent containing a hydroxyl group-containing acrylic resin, a melamine resin, and a single-end-modified silicone oil, one end of which has been modified with a hydroxyl group.

[0009] The present invention (2) includes the release coating agent according to (1), in which the content ratio of the one-end-modified silicone oil relative to a total of 100 parts by mass of the hydroxyl group-containing acrylic resin and the melamine resin is 0.03 parts by mass or more and 5.0 parts by mass or less.

[0010] The present invention (3) includes a release coating agent according to (1) or (2), wherein the one-terminal-modified silicone oil has silicon at one terminal modified with a carbinol group and / or a diol.

[0011] The present invention (4) includes a release coating agent according to any one of (1) to (3), wherein the one-terminal-modified silicone oil has silicon at one terminal modified with a carbinol group.

[0012] The present invention (5) includes the release coating agent according to any one of (1) to (4), wherein the melamine resin is at least one selected from the group consisting of methyl-type melamine resins and methylol-type melamine resins.

[0013] The present invention (6) includes the release coating agent according to any one of (1) to (5), wherein the content of mononuclear molecules in the melamine resin is 60% by mass or more and 90% by mass or less.

[0014] The present invention (7) includes a release film comprising, in order toward one side in the thickness direction, a base film and a release layer comprising a coating of the release coating agent according to any one of (1) to (6).

[0015] The present invention (8) includes a method for producing a release film according to (7), which includes the steps of: producing the release film by applying the release coating agent to one surface of the base film in the thickness direction to form the release layer; and positioning the release film so that one surface of the release layer in the thickness direction is in contact with the other surface of the base film in the thickness direction.

[0016] The present invention (9) includes the method for producing a release film according to (8), wherein the release film is long, and in the step of arranging the release film, the release film is wound up as a roll.

[0017] The present invention (10) includes the method for producing a release film according to (8) or (9), wherein in the step of producing the release film, the coating film of the release coating agent is heated at less than 130°C for 4 seconds or more and 100 seconds or less. [Effects of the Invention]

[0018] In the method for producing a release film of the present invention, the release coating agent of the present invention is applied to one side of a film in the thickness direction and dried to form a release layer, thereby producing the release film of the present invention, and when this release layer comes into contact with the other side of the base film in the thickness direction, it is possible to prevent some of the components of the release layer from migrating to the other side of the base film. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a cross-sectional view of one embodiment of the release film of the present invention. [Figure 2] FIG. 2 shows an embodiment in which a functional layer is applied to the other side of the release film of FIG. [Figure 3] 3A to 3C are diagrams illustrating the offset test of the examples. Fig. 3A shows a mode in which two release films are prepared. Fig. 3B shows a mode in which a laminate is produced. Fig. 3C shows a mode in which one release film is peeled off from the other release film and a functional layer is disposed on the other surface of one release film. [Figure 4] FIG. 4 shows an image-processed plan view of the coating film of Example 1. [Figure 5] FIG. 5 shows an image-processed plan view of the coating film of Comparative Example 6. [Figure 6] FIG. 6 shows a processed image of a plan view of the coating film of Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0020] 1. Release coating agent The release coating agent is, for example, a thermosetting composition that can be applied, dried, and cured to form a release layer. The release coating agent of the present invention contains a hydroxyl group-containing acrylic resin, a melamine resin, and a one-terminal-modified silicone oil.

[0021] 1.1 Hydroxyl-containing acrylic resin The hydroxyl group-containing acrylic resin contains hydroxyl groups. The hydroxyl value of the hydroxyl group-containing acrylic resin is, for example, 100 mgKOH / g or more, preferably 125 mgKOH / g or more, more preferably 150 mgKOH / g or more, and even more preferably 160 mgKOH / g or more. The hydroxyl value of the hydroxyl group-containing acrylic resin is, for example, 500 mgKOH / g or less, preferably 300 mgKOH / g or less, and more preferably 200 mgKOH / g or less.

[0022] If the hydroxyl value of the hydroxyl group-containing acrylic resin is equal to or greater than the above-mentioned lower limit, drying at low temperatures and in a short time is possible, and improved productivity can be expected. If the hydroxyl value of the hydroxyl group-containing acrylic resin is equal to or less than the above-mentioned upper limit, the pot life after preparation of the release coating agent can be extended. In this embodiment, the pot life refers to the life after mixing the components of the one-component release coating. In the case of the two-component release coating agent described in the modified example, it refers to the life after mixing the A and B components.

[0023] The hydroxyl value is measured by a method conforming to the neutralization titration method (JIS-K0070K). If the hydroxyl group-containing acrylic resin is a commercially available product (described below), the catalog value is used as the hydroxyl value. In addition, the theoretical hydroxyl value can be calculated from the composition of the monomer components described below.

[0024] The weight-average molecular weight of the hydroxyl group-containing acrylic resin is 5,000 or more and 100,000 or less. The weight-average molecular weight is determined as a polystyrene equivalent value by gel permeation chromatography (GPC).

[0025] The hydroxyl group-containing acrylic resin may be a commercially available product, or may be prepared by the following method.

[0026] Monomer components containing a hydroxyl group-containing (meth)acrylate and an alkyl (meth)acrylate as main components are blended together, and the monomer components are polymerized.

[0027] Hydroxyl group-containing (meth)acrylates include hydroxyl group-containing methacrylates and hydroxyl group-containing acrylates. The usage of "(meth)" is the same hereinafter. Hydroxyl group-containing (meth)acrylates are not limited. Examples of hydroxyl group-containing (meth)acrylates include hydroxyalkyl (meth)acrylates. The number of carbon atoms in the alkyl in the hydroxyalkyl (meth)acrylate is, for example, 2 or more and 6 or less. Specific examples of hydroxyalkyl (meth)acrylates include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxyisopropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxypentyl (meth)acrylate, and hydroxyhexyl (meth)acrylate.

[0028] The alkyl(meth)acrylate is not limited. The alkyl(meth)acrylate does not contain a hydroxyl group. The number of carbon atoms in the alkyl in the alkyl(meth)acrylate is, for example, 1 or more and 12 or less. Specific examples of the alkyl(meth)acrylate include methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, isopropyl(meth)acrylate, butyl(meth)acrylate, pentyl(meth)acrylate, hexyl(meth)acrylate, heptyl(meth)acrylate, octyl(meth)acrylate, nonyl(meth)acrylate, decyl(meth)acrylate, undecyl(meth)acrylate, and dodecyl(meth)acrylate.

[0029] The monomer component optionally contains a vinyl monomer copolymerizable with the main component. The vinyl monomer is not limited. Examples of the vinyl monomer include aromatic vinyl monomers. Examples of the aromatic vinyl monomer include styrene and vinyl toluene.

[0030] The blending ratio of the hydroxyl group-containing (meth)acrylate in the monomer component is, for example, 25% by mass or more and 50% by mass or less. The blending ratio of the alkyl (meth)acrylate in the monomer component is, for example, 20% by mass or more and 45% by mass or less. The blending ratio of the copolymerizable vinyl monomer in the monomer component is, for example, 10% by mass or more and 40% by mass or less.

[0031] The monomer components are polymerized in the presence of a known polymerization initiator. The polymerization method is not limited. For example, solution polymerization is used. In solution polymerization, an organic solvent is used.

[0032] The content of the hydroxyl group-containing acrylic resin in the release coating agent (solid content) is, for example, 35 mass % or more, preferably 40 mass % or more, and for example, 75 mass % or less, preferably 60 mass % or less.

[0033] 1.2 Melamine resin Melamine resin is a condensation resin of melamine and formaldehyde. Melamine has a functional group. Melamine resin includes mononuclear and polynuclear compounds. Mononuclear compounds have a structure having one melamine skeleton represented by the following formula (1). Polynuclear compounds have a structure having multiple melamine skeletons.

[0034] [ka]

[0035] The content of mononuclear molecules in the melamine resin is, for example, 20% by mass or more, preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, and particularly preferably 77% by mass or more, and for example, 95% by mass or less, preferably 90% by mass or less, and more preferably 85% by mass or less. When the content of mononuclear molecules in the melamine resin is equal to or greater than the above-mentioned lower limit, the coating film (described below) can be cured at a low temperature (preferably less than 100°C). When the content of mononuclear molecules in the melamine resin is equal to or less than the above-mentioned upper limit, handling properties during production can be ensured.

[0036] The content of mononuclear bodies in a melamine resin is the percentage of mononuclear bodies relative to the total of mononuclear bodies and polynuclear bodies. If the melamine resin is a commercially available product, the value listed in the catalog is used as the content of mononuclear bodies in the melamine resin. The content of mononuclear bodies in a melamine resin can be measured, for example, by GPC. In GPC, a calibration curve is created using a standard product of mononuclear bodies, and the content of mononuclear bodies is measured using the calibration curve.

[0037] Melamine resins are classified by the number and type of functional groups they contain. Examples of functional groups include methylol groups (-CHOH), methoxymethyl ether groups (-CHOCH), and imino groups (>NH). Examples of melamine resins include methylol-type melamine resins, methoxymethyl ether-type melamine resins, and imino-type melamine resins.

[0038] Methylol-type melamine resins have methylol groups as functional groups. Methoxymethyl ether-type melamine resins have methoxymethyl ether groups as functional groups. Methoxymethyl ether-type melamine resins are called methyl-type melamine resins because the terminal end of the methoxymethyl ether group is methyl. Methyl-type melamine resins also include full-ethermethyl melamine resins in which two methoxymethyl ether groups are bonded to each of the three nitrogen atoms located on the outside of the melamine skeleton. Full-ethermethyl melamine resins have six methoxymethyl ether groups per mononuclear unit. The imino-type melamine resin has an imino group as a functional group.

[0039] As the melamine resin, from the viewpoint of drying (curing) at low temperature in a short time, preferred examples include methylol-type melamine resin and methyl-type melamine resin, and more preferred examples include methyl-type melamine resin from the viewpoint of ensuring even better easy releasability. Easy releasability is the property that allows the adhesive body to be peeled off from the release layer with a small force. The adhesive body includes an adhesive tape.

[0040] The melamine resin may be commercially available, such as the Cymel series (manufactured by Allnex Japan), the Nikalac series (manufactured by Sanwa Chemical), the U-Ban series (manufactured by Mitsui Chemicals), and the Amidia series (manufactured by DIC).

[0041] The content of the melamine resin in the release coating agent (solid content) is, for example, 35% by mass or more, preferably 40% by mass or more, and for example, 75% by mass or less, preferably 60% by mass or less. The content of the melamine resin relative to 100 parts by mass of the hydroxyl group-containing acrylic resin is, for example, 75 parts by mass or more, preferably 90 parts by mass or more, and for example, 150 parts by mass or less, preferably 110 parts by mass or less.

[0042] 1.3 Single-end modified silicone oil Single-end-modified silicone oil is a silicone oil (organosiloxane) in which one end is modified with a hydroxyl group. Examples of single-end-modified silicone oil include carbinol-modified silicone oil and diol-modified silicone oil. Carbinol-modified silicone oil is a silicone oil in which the silicon at one end is modified with a carbinol group. The carbinol group is C-OH. Diol-modified silicone oil is a silicone oil in which the silicon at one end is modified with an alkyldiol (-R 1 -R 0 (R 2 It is a silicone oil modified with hydroxypropyl hydroxypropyl methyl acrylate.

[0043] Examples of the one-end-modified silicone oil include carbinol-modified silicone oil and diol-modified silicone oil, and preferably, from the viewpoint of light release properties, carbinol-modified silicone oil is used.

[0044] The kinematic viscosity of the one-end-modified silicone oil is not limited. For example, the kinematic viscosity of the one-end-modified silicone oil at 25°C is 2 / s or more, and for example, 1,000 mm 2 The kinematic viscosity of the carbinol-modified silicone oil at 25°C is, for example, 10 mm 2 / s or more, preferably 20 mm 2 / s or more, more preferably 30 mm 2 / s or more, and for example, 100 mm 2 / s or less, preferably 80 mm 2 The kinematic viscosity of the diol-modified silicone oil at 25°C is, for example, 50 mm 2 / s or more, preferably 100 mm 2 / s or more, and for example, 750 mm 2 / s or less, preferably 600 mm 2 / s or less.

[0045] The content of the mono-terminally modified silicone oil relative to 100 parts by mass of the combined total of the hydroxyl group-containing acrylic resin and the melamine resin is, for example, 0.03 parts by mass or more, preferably 0.1 parts by mass or more, more preferably 0.15 parts by mass or more, even more preferably 0.2 parts by mass or more, particularly preferably 0.5 parts by mass or more, and for example, 10 parts by mass or less, preferably 5 parts by mass or less, more preferably 3.0 parts by mass or less, even more preferably 1.0 parts by mass or less, particularly preferably 0.6 parts by mass or less. When the content of the mono-terminally modified silicone oil relative to 100 parts by mass of the combined total of the hydroxyl group-containing acrylic resin and the melamine resin is equal to or greater than the above-mentioned lower limit, excellent easy peelability is achieved. When the content of the mono-terminally modified silicone oil relative to 100 parts by mass of the combined total of the hydroxyl group-containing acrylic resin and the melamine resin is equal to or less than the above-mentioned upper limit, when the release layer formed on one side of the substrate film (described below) comes into contact with the other side of the substrate film, migration of some of the components of the release layer to the other side of the substrate film can be more reliably prevented.

[0046] To prepare the release coating agent, a hydroxyl group-containing acrylic resin, a melamine resin, and a one-terminal modified silicone oil are blended.

[0047] The release coating agent may further contain an acid catalyst. The acid catalyst is not limited. Examples of acid catalysts include organic acids and inorganic acids. The organic acid is not limited. Examples of organic acids include organic carboxylic acids, organic sulfonic acids, and organic phosphoric acids. Examples of organic carboxylic acids include oxalic acid, acetic acid, and formic acid. Examples of organic sulfonic acids include aromatic sulfonic acids and aliphatic sulfonic acids. Examples of aromatic sulfonic acids include benzenesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, and naphthalenesulfonic acid.

[0048] Aliphatic sulfonic acids include, for example, methanesulfonic acid and hexanesulfonic acid. Organic phosphoric acids include, for example, methyl acid phosphate and phenyl acid phosphate. Inorganic acids are not limited. Inorganic acids include, for example, hydrochloric acid, sulfuric acid, and nitric acid.

[0049] The acid catalyst is preferably an organic acid, more preferably an organic sulfonic acid, and even more preferably an aromatic sulfonic acid.

[0050] The content ratio of the acid catalyst relative to a total of 100 parts by mass of the hydroxyl group-containing acrylic resin and the melamine resin is, for example, 0.1 parts by mass or more, preferably 1 part by mass or more, and for example, 10 parts by mass or less, preferably 5 parts by mass or less.

[0051] The release coating agent can also be prepared as a coating liquid by further blending an organic solvent. The vapor pressure of the organic solvent at 25°C is, for example, 1 kPa or more, preferably 3 kPa or more, more preferably 5 kPa or more, and 100 kPa or less. Examples of organic solvents include ketone-based solvents, ester-based solvents, and alcohol-based solvents. Examples of ketone-based solvents include methyl ethyl ketone and methyl isobutyl ketone. Examples of ester-based solvents include ethyl acetate and butyl acetate. Examples of alcohol-based solvents include methanol, ethanol, propyl alcohol, and isopropyl alcohol (isopropanol, IPA). The solids concentration in the coating liquid is not limited. The solids concentration in the coating liquid is, for example, 10% by mass or more, preferably 20% by mass or more, more preferably 30% by mass or more, and for example, 80% by mass or less, preferably 60% by mass or less, more preferably 50% by mass or less.

[0052] In addition to the above-mentioned components, the release coating agent may contain additives in appropriate proportions, such as defoamers, anti-slip agents, preservatives, rust inhibitors, pH adjusters, antioxidants, pigments, dyes, lubricants, leveling agents, and conductive agents.

[0053] 2. Release film Next, one embodiment of the release film will be described with reference to FIG.

[0054] As shown in Fig. 1, in this embodiment, the release film 1 is, for example, long. The long direction of the release film 1 is perpendicular to the thickness direction. The release film 1 includes a base film 2 and a release layer 3, which are arranged in this order toward one side in the thickness direction. Preferably, the release film 1 includes only the base film 2 and the release layer 3.

[0055] 2.1 Base film 2 In this embodiment, the base film 2 is long. The base film 2 forms the other surface of the release film 1 in the thickness direction. The base film 2 is not limited. The base film 2 has, for example, flexibility. Examples of the base film 2 include plastic films. Examples of plastic films include polyester films, polycarbonate films, polymethyl methacrylate films, polyolefin films (including cycloolefin polymer films), nylon films, epoxy resin films, triacetyl cellulose films, ABS resin films, AS resin films, and norbornene resin films. Examples of the base film 2 include metal foils. Further examples of the base film 2 include paper. Examples of the base film 2 include plastic films, and more preferably polyester films. Examples of polyester films include polyethylene terephthalate (PET) films and polyethylene naphthalate (PEN) films. Examples of the polyester films include PET films. The thickness of the base film 2 is, for example, 5 μm or more, or preferably 20 μm or more, and for example, 1,000 μm or less, or preferably 500 μm or less.

[0056] The release layer 3 forms one surface of the release film 1 in the thickness direction. The release layer 3 is disposed on one surface of the base film 2 in the thickness direction. The release layer 3 is in contact with one surface of the base film 2 in the thickness direction. The release layer 3 is made of a coating film 30 of the release coating agent described above. The thickness of the release layer 3 is, for example, 0.1 μm or more, preferably 0.5 μm or more, and for example, 10.0 μm or less, preferably 5.0 μm or less. The basis weight of the release layer 3 is, for example, 0.1 g / m 2 More than 0.5 g / m 2 or more, and for example, 10 g / m 2 Preferably, 5 g / m or less 2 The following is the result.

[0057] 3. Method for producing release film 1 The method for producing the release film 1 includes a step of forming the release layer 3 on the base film 2 and a step of winding up the release film 1.

[0058] 3.1 Step of forming release layer 3 In the step of forming the release layer 3, a release coating agent is applied to one surface of the substrate film 2 in the thickness direction and dried. The method for applying the release coating agent is not limited. Examples of methods for applying the release coating agent include a gravure coater, a knife coater, a bar coater, a dot coater, a roll coater, a reverse roll coater, and a spray. By applying the release coating agent, a coating film 30 is formed on one surface of the substrate film 2 in the thickness direction.

[0059] Subsequently, the coating film 30 is dried. Specifically, the coating film 30 is heated. The heating temperature is, for example, less than 130°C, preferably less than 100°C, more preferably 98°C or less, more preferably 95°C or less, and for example, 60°C or more, preferably 75°C or more. If the heating temperature is below the above-mentioned upper limit, the load in the production of the release film 1 can be reduced. The heating time is, for example, 4 seconds or more, preferably 20 seconds or more, more preferably 30 seconds or more, and for example, 300 seconds or less, preferably 100 seconds or less. If the heating time is equal to or greater than the above-mentioned lower limit, the load in the production of the release film 1 can be reduced, and production efficiency is excellent.

[0060] By heating and drying the coating film 30, the organic solvent, which is added as needed, is removed, and the hydroxyl group-containing acrylic resin, melamine resin, and one-terminal-modified silicone oil react (thermosetting) in the presence of an acid catalyst, which is added as needed. This causes the coating film 30 to be thermoset, forming the release layer 3. This produces a release film 1 in which the base film 2 and the release layer 3 are arranged in this order toward one side in the thickness direction.

[0061] 3.2 Step of winding the release film 1 into a roll 5 In the step of winding up the release film 1, the long release film 1 is wound up around a roll 5. Specifically, the roll 5 is arranged so that it is wound up in the longitudinal direction. As shown in the enlarged view of Figure 1, in the roll 5, one side of the release layer 3 in the thickness direction comes into contact with the other side of the base film 2 in the thickness direction.

[0062] 4. Use of release film 1 To use the release film 1, for example, the release film 1 is unwound from a roll 5 as shown in Fig. 2, and then a functional layer 4 is disposed on the other surface of the release film 1 in the thickness direction. Examples of the functional layer 4 include an adhesive layer and a paint layer. The paint layer includes, for example, a printing layer (or a printed layer).

[0063] This results in a functional film 6 having the functional layer 4, the base film 2, and the release layer 3 arranged in this order toward one side in the thickness direction. If the functional layer 4 is an adhesive layer, the functional film 6 is manufactured as an adhesive film 60.

[0064] 5. Effects This release coating agent contains a hydroxyl group-containing acrylic resin, a melamine resin, and a single-end-modified silicone oil, one end of which has been modified with a hydroxyl group. As shown in FIG. 1 , this release coating agent is applied to one side of a long substrate film 2 and dried to form a release layer 3. When a release film 1, which includes the substrate film 2 and the release layer 3 in this order along one thickness direction, is wound into a roll 5, the release layer 3 comes into contact with the other side of the substrate film 2 in the thickness direction. At this time, migration of some of the components of the release layer 3 (release components) to the other side of the substrate film 2 can be prevented. This migration is referred to as offset. However, offset in this embodiment does not include a situation in which some of the components of the release layer 3 disposed on one side of the substrate film 2 progress (permeate) toward the other side of the substrate film 2 along the thickness direction and migrate to the other side of the substrate film 2. In this embodiment, the aforementioned set-off is suppressed, so that after the release film 1 is wound into a roll 5, the functional layer 4 can be uniformly disposed on the other side of the base film 2 unwound from the roll 5. Therefore, as shown in Figure 2, a highly reliable functional film 6 can be produced.

[0065] On the other hand, when the release coating agent contains a silicone oil modified at both ends, as in Patent Document 1, the above-mentioned set-off cannot be suppressed, and therefore the functional layer 4 cannot be uniformly disposed on the other surface of the substrate film 2 in the thickness direction. For example, when the functional layer 4 is formed by applying a coating liquid, the set-off component (release component) causes the coating liquid to be repelled, resulting in defective portions.

[0066] 6. Variations In the following modifications, the same components and steps as those in the above-described embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted. Furthermore, each modification can achieve the same effects as those in the above-described embodiment unless otherwise specified. Furthermore, the embodiment and modifications can be combined as appropriate.

[0067] As shown in Figure 3A, multiple release films 1A, 1B can be produced by a sheet-feed method. In this case, as shown in Figure 3B, multiple release films 1A, 1B are laminated in the thickness direction using sheets. For example, release film 1B is stacked on top of release film 1A. A laminate 7 is produced that includes two release films 1A, 1B. In this case, in the laminate 7, one surface of release layer 3A in the thickness direction contacts the other surface of base film 2B in the thickness direction.

[0068] 3C, release film 1B is then peeled off from release layer 3A of release film 1A. Then, functional layer 4B is disposed on the other surface of base film 2B of release film 1B by, for example, coating.

[0069] 6.1 Effects of Modifications In Figure 3B, it is possible to prevent a portion of the components of the release layer 3A in the release film 1A from migrating to the other side of the base film 2B in the release film 1B. In other words, it is possible to prevent the components of the release layer 3A from being transferred to the back side of the base film 2B. Therefore, as shown in Figure 3C, it is possible to uniformly arrange the functional layer 4B on the other side of the base film 2 in the thickness direction.

[0070] 7. Other Variations In one embodiment, the release coating agent is a one-component type containing a hydroxyl group-containing acrylic resin, a melamine resin, a one-terminal-modified silicone oil, and, if necessary, an acid catalyst. A variant may be a two-component type. The two-component release coating agent contains separate components, A and B. Component A, for example, contains a hydroxyl group-containing acrylic resin, a melamine resin, and a one-terminal-modified silicone oil. Component B, for example, contains an acid catalyst. [Example]

[0071] Specific numerical values ​​of blending ratios (content ratios), physical property values, parameters, etc. used in the following description can be replaced with the corresponding upper limit values ​​(numeric values ​​defined as "not more than" or "less than") or lower limit values ​​(numeric values ​​defined as "not less than" or "exceeding") of blending ratios (content ratios), physical property values, parameters, etc. described in the above "Modes for Carrying Out the Invention." Furthermore, unless otherwise specified in the following description, "parts" and "%" are based on mass.

[0072] Details of the components used in each example and comparative example are given below. Hydroxyl group-containing acrylic resin: Preparation Example 1 described below, hydroxyl value = 173 mg KOH / g Cymel 300: Full ether methyl melamine resin, mononuclear content: 80-84% by mass, manufactured by Allnex Japan Co., Ltd. Cymel 303FL: Full ether methyl melamine resin, mononuclear content: 68-75% by mass, manufactured by Allnex Japan Co., Ltd. Cymel 370N: Methylol melamine resin, mononuclear content: 35-40% by mass, manufactured by Allnex Japan Co., Ltd. Cycat 4040: p-toluenesulfonic acid, acid catalyst, 40% solids, Allnex Japan Co., Ltd. X-22-170DX: One-terminated carbinol-modified silicone oil, kinematic viscosity at 25°C: 65mm 2 / s, manufactured by Shin-Etsu Chemical Co., Ltd. X-22-170BX: One-terminal carbinol-modified silicone oil, kinematic viscosity at 25°C: 40mm 2 / s, manufactured by Shin-Etsu Chemical Co., Ltd. X-22-176DX: One-terminal diol-modified silicone oil, kinematic viscosity at 25°C: 130mm 2 / s, manufactured by Shin-Etsu Chemical Co., Ltd. X-22-176F: One-terminal diol-modified silicone oil, kinematic viscosity at 25°C: 500mm 2 / s, manufactured by Shin-Etsu Chemical Co., Ltd. KF-6003: Both-end carbinol-modified silicone oil, kinematic viscosity at 25°C: 110mm 2 / s, manufactured by Shin-Etsu Chemical Co., Ltd. X-22-173DX: One-terminated epoxy-modified silicone oil, kinematic viscosity at 25°C: 60mm 2 / s, manufactured by Shin-Etsu Chemical Co., Ltd. Isopropanol: Vapor pressure 6 kPa at 25°C

[0073] Preparation Example 1 (Preparation of Hydroxyl-Containing Acrylic Resin) A glass reactor equipped with a stirrer, thermometer, reflux condenser, and dropping device was charged with 80.0 parts by weight of butyl acetate and heated to 90-100°C. A mixture of 40.0 parts by weight of 2-hydroxyethyl methacrylate, 25.0 parts by weight of methyl methacrylate, 25.0 parts by weight of styrene, 10.0 parts by weight of butyl acrylate, 4.0 parts by weight of Niper BW (polymerization initiator, containing 25% by weight of water), and 20.0 parts by weight of butyl acetate was added dropwise over 4 hours under nitrogen aeration. After polymerization at 90-100°C for 2 hours, an additional 0.2 parts by weight of Niper BW was added and polymerization continued for another 2 hours to obtain a 50% by weight butyl acetate solution of hydroxyl-containing acrylic resin. The theoretical hydroxyl value of the hydroxyl-containing acrylic resin was 173 mg KOH / g (56100 × (40.0 / 130) / 100). The weight-average molecular weight (Mw) calculated as polystyrene by GPC was 30,000. In the above formula in parentheses, 40 is the blending ratio of 2-hydroxyethyl methacrylate, 130 is the molecular weight of 2-hydroxyethyl methacrylate, and 100 means the blending ratio of the total monomer components.

[0074] Example 1 (Release coating agent manufacturing) A release coating agent was prepared by blending 100.00 parts by weight of the hydroxyl group-containing acrylic resin of Preparation Example 1 (50.00 parts by weight as solids), 50.00 parts by weight of a full ether methyl melamine resin (Cymel 300), 0.60 parts by weight of a mono-terminated carbinol-modified silicone oil (X-22-170DX), 4.00 parts by weight of p-toluenesulfonic acid (Cycat 4040) (1.60 parts by weight as solids), and isopropanol to a solids concentration of 40% by weight. The blending recipe is shown in Table 1. The values ​​in Table 1 represent the solids blend ratios. The same applies to Table 2.

[0075] Example 1-a (Production of Release Film 1) The release coating agent of Example 1 was applied to one side of a substrate film 2 made of a PET film having a thickness of 38 μm, and the coating film 30 (release layer 3) after drying had a basis weight of 2.0 g / m 2 Thereafter, the coating film 30 was heated at 120° C. for 60 seconds to form the release layer 3. In this way, a release film 1 was produced which was provided with the base film 2 and the release layer 3 in this order towards one side in the thickness direction.

[0076] Example 1-b (Production of Release Film 1) Release film 1 was produced in the same manner as in Example 1-a, except that the heating temperature was changed to 90°C.

[0077] Example 2 to Example 6, Example 10. Example 11, Comparative Example 1 from Comparative Example 6 (Production of release coating agent and release film 1) A release coating agent was prepared in the same manner as in Example 1, and Release Film 1 was produced in the same manner as in Example 1-a, except that the formulation of the release coating agent was changed as shown in Tables 1 and 2.

[0078] Example 13 (Production of Release Film 1) comparison example5 Release film 1 was produced in the same manner as in the above, except that the heating temperature was changed to 100°C.

[0079] Example 14 (Production of Release Film 1) Release film 1 was produced in the same manner as in Example 10, except that the heating temperature was changed to 100°C.

[0080] <Evaluation> Example 1-a to Example 6. Example 10. Example 11 , Comparative Example 1 from Comparative Example 6 The following points were evaluated for Release Film 1. The results are shown in Tables 1 and 2 (Examples 13 and 14 will be described later).

[0081] 1. Set-through As shown in Figure 3A, one release film 1 was cut into a size of 10 cm x 10 cm to prepare two release films 1A and 1B. As shown in Figure 3B, release film 1B was stacked on top of release film 1A to prepare laminate 7. The top and bottom surfaces of laminate 7 were clamped in a vice, pressure was applied to laminate 7, and it was left to stand for two days.

[0082] As shown in Figure 3C, release film 1B was peeled from release layer 3A of release film 1A. Test paint 4B was then applied to the other side of base film 2B of release film 1B. The test paint contained 38 parts by weight of IPA, 4.0 parts by weight of polyester polyol (dispersant: Kuraray Polyol P-510), and 0.4 parts by weight of dye. The coating film made from the test paint was visually observed, and the offset was evaluated according to the following criteria.

[0083] ◯: No repellency of the test paint was observed on the other surface of the base film 2B (see FIG. 4). Δ: Slight repellency of the test paint was observed in part of the other surface of the base film 2B (see FIG. 5). ○~△: Repelling was observed to an intermediate level between the above ○ and △. ×: Repelling of the test paint was observed over the entire other surface of the base film 2B (see FIG. 6).

[0084] FIG. 4 shows an image-processed plan view of the coating film of Example 1. comparison example 6 An image-processed plan view of the coating film of Comparative Example 1 is shown in Fig. 5. An image-processed plan view of the coating film of Comparative Example 1 is shown in Fig. 6.

[0085] 2. Peelability As shown in Figure 3C, a 25 mm wide adhesive tape (No. 31B, manufactured by Nitto Denko Corporation) 8 was attached to one side of the release layer 3B of the release film 1B, and then the peel load was measured when peeling the adhesive tape 8 from the release layer 3B. The peeling speed was 300 mm / min.

[0086] [Table 1]

[0087] [Table 2]

[0088] The offset resistance of Example 13 was evaluated as ○ and the peel load was 5.7 (g / 25 mm). The offset resistance of Example 14 was evaluated as ○ to △ and the peel load was 5.0 (g / 25 mm). [Explanation of symbols]

[0089] 1 Release film 2. Base film 3 Peeling layer 30 Release coating film

Claims

1. a hydroxyl group-containing acrylic resin; A melamine compound, and a single-end-modified silicone oil, one end of which is modified with a hydroxyl group, The release coating agent has a content of the one-end-modified silicone oil of 0.50 parts by mass or more and 3.0 parts by mass or less relative to a total of 100 parts by mass of the hydroxyl group-containing acrylic resin and the melamine compound.

2. 2. The release coating agent according to claim 1, wherein the silicon atom at one end of the one-end-modified silicone oil is modified with a carbinol group and / or a diol.

3. 2. The release coating agent according to claim 1, wherein the one-terminal-modified silicone oil has a silicon atom at one terminal modified with a carbinol group.

4. 2. The release coating agent according to claim 1, wherein the melamine compound is at least one selected from the group consisting of methyl-type melamine resins and methylol-type melamine resins.

5. 2. The release coating agent according to claim 1, wherein the content of mononuclear units in the melamine compound is 60% by mass or more and 90% by mass or less.

6. A release film comprising a substrate film and a release layer formed by coating the release coating agent according to any one of claims 1 to 5, arranged in this order toward one side in the thickness direction.

7. A method for producing the release film according to claim 6, a step of applying the release coating agent to one surface of the substrate film in the thickness direction to form the release layer, thereby producing the release film; and positioning the release film so that one surface of the release layer in the thickness direction is in contact with the other surface of the base film in the thickness direction.

8. The release film is long, In the step of disposing the release film, the release film is wound up as a roll. A method for producing the release film according to claim 7.

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