JP2018089955A - Method for producing release paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing release paper of high quality causing no problem in heavy release and surface roughness.SOLUTION: A method for producing release paper having a paper base material 1, a sealing layer 3a and a release agent layer 5 includes: a step of laminating the sealing layer 3a on a paper base material 1; and a step of applying a mixture containing an aminoalkyd resin and an epoxy resin in a specific mass ratio and containing no silicon-based compound onto the sealing layer 3a, and thermally curing the mixture at 110-140°C to form a release agent layer 5.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing a release paper that is attached to an object to protect the surface of the object and maintain the properties of the surface. More specifically, one embodiment of the present invention relates to a method for manufacturing release paper, wherein the object is a component member (for example, a substrate) of an electronic component.

  Conventionally, coverlay films equipped with base materials (polyimide film and polyester film, etc.) and adhesives (polyimide resin, epoxy resin, etc.) are widely used for electronic materials such as flexible printed circuit (FPC) boards. Has been. A release paper is attached to the adhesive surface of the coverlay film in order to protect the adhesive surface until an adherend such as a metal foil is adhered to the coverlay film.

  As described above, the release paper is used for the purpose of temporarily protecting the coverlay film. Therefore, before the coverlay film is bonded to the adherend, the release paper is peeled off from the coverlay film. In order to improve the releasability at this time, the release paper is generally provided with a release agent layer obtained by applying a release agent to at least one surface of a paper substrate and thermally curing the release agent. Usually, a sealing layer is provided between the paper substrate and the release agent layer in order to prevent the release agent from penetrating into the paper substrate when the release agent is applied. In general release paper, a silicone release agent mainly composed of dimethylsiloxane is used. However, in the application of electronic materials such as FPC boards, silicon components (for example, low molecular weight silicone resins) migrate to the adhesive layer of the coverlay film, which contaminates the adherends such as the boards, electrical connection parts, etc. Use of a silicone release agent is avoided. Therefore, non-silicone release agents, particularly release agents using amino alkyd resin, which is a mixture of amino resin and alkyd resin, are often used in electronic materials. Patent documents 1-3 are mentioned as literature which discloses an example using such an amino alkyd release agent.

  Patent Document 1 discloses that (A) an alkyd resin and (B) a melamine resin having an average of 0.1 to 2 primary and / or secondary amino groups per triazine nucleus in a solid content weight ratio of 70:30 to 10 : A release agent composition characterized in that it is used for forming a release agent layer in a release sheet that is contained in a ratio of 90 and to which a polyimide adhesive is applied.

  Patent Document 2 describes a release film in which a release layer composed of (A) a thermosetting resin and (B) an alkyd resin modified with a saturated fatty acid is provided on at least one surface of a thermoplastic resin film. .

  In Patent Document 3, as a release agent composition that gives a release sheet having a good balance between wettability when an adhesive resin is applied and release property of the adhesive resin layer formed by application, a bisphenol type resin, A release agent composition containing a thermosetting resin and a modified alkyd resin is described.

JP 2004-277614 A Japanese Patent Laid-Open No. 10-6459 JP 2007-106856 A

In Patent Documents 1 to 3, there is no mention that the temperature condition for thermosetting the release agent affects the quality of the release paper. However, the inventors of the present application pay attention to the above temperature condition for the purpose of improving the quality of the conventional release paper, and the release agent layer in the release paper so far has actually caused the following problems. I found out.
(1) At a low curing temperature (for example, 110 ° C. or lower), unreacted (uncured) aminoalkyd resin remains in the release agent layer, and during storage or transportation of the coverlay film with the release paper attached, Unreacted amino alkyd resin reacts with the adhesive component of the coverlay film, making it difficult for the release paper to peel from the coverlay film (heavy release of the release paper).
(2) At high curing temperatures, the heavy release of the release paper is eliminated, but the moisture contained in the paper substrate evaporates to cause unevenness in the eye stop layer, resulting in the release paper The surface is roughened (the surface condition is poor). It was also unknown to the inventors of the present application how many degrees Celsius these phenomena appear. However, it has been found that at 150 ° C. or higher, these phenomena occur remarkably, and the surface state of the release paper becomes extremely poor.

  An object of the present invention is to provide a method for producing a high-quality release paper that does not cause the problems (1) and (2).

  The present invention includes a paper base material, a sealing layer, and a release agent layer, and the release agent layer is laminated on the sealing layer laminated on at least one surface of the paper base material. A method for producing a release paper, the step of laminating the filler layer on at least one surface of the paper substrate, and a mixture containing an aminoalkyd resin and an epoxy resin and not containing a silicon compound Is applied to the sealing layer, and the mixture is thermally cured at 115 to 140 ° C. to form the release agent layer, and the mixture is included in the mixture. When the total amount of amino alkyd resin and epoxy resin is 100% by mass, 84.0 to 98.8% by mass of amino alkyd resin and 1.2 to 16.0% by mass of epoxy resin are included. Ri, the amino alkyd resin, an amino resin and an alkyd resin 10: 90-80: comprising 20 weight ratio, a method for producing a release paper.

  According to the production method of the present invention, a high-quality release paper can be provided.

It is a figure which shows the process in the manufacturing method of each embodiment of this invention.

  One embodiment of the present invention includes a paper base material, a sealing layer, and a release agent layer, and the release agent layer is laminated on at least one surface of the paper base material. This is a method for manufacturing release papers laminated in layers. For convenience of explanation, after explaining the configuration of the release paper, the details of the manufacturing method will be explained. In the following description, the numerical values (and their units) shown at both ends of the symbol “to” represent the upper and lower limits such as the properties and states indicated by the numerical values (and their units). Yes. Therefore, “A to B” is synonymous with “A or more and B or less” and is interchangeable.

[Release paper]
The release paper includes a paper substrate, a sealing layer, and a release agent layer. In the release paper as a product, the sealing layer is formed (laminated) independently on both sides of the paper substrate, and a release agent layer is formed on at least one of the sealing layer ( Laminated). The release agent layer is mainly composed of a resin mixture that does not contain a silicon-based compound. Therefore, as described in the background art, the preferable use of the release paper is an electronic material application such as an FPC board. For example, by protecting the adhesive surface of the coverlay film that constitutes a part of the FPC board. is there. Of course, the release paper can be used for other applications, but for the sake of convenience of explanation, the configuration of the release paper will be described in detail below, taking the release paper protecting the coverlay film as an example.

(Release agent layer)
The release agent layer is for easily peeling the release paper from the cover lay film before the cover lay film is bonded to an adherend (for example, a copper foil that is a source of wiring on an FPC board). Is a layer. The release agent layer is a layer formed by thermal curing of a mixture of amino alkyd resin and epoxy resin. The mixture does not contain a silicon compound that is unsuitable for use in an FPC substrate. The mixture will be described in detail later in the item relating to the production method. The release agent layer is laminated on one surface of the two surfaces of the paper base material via the sealing layer. In addition, although it demonstrated that the said release agent layer was laminated | stacked only on the one surface side of the said paper base material here, on the other surface side of the said paper base material as needed in another use. It can be laminated also on the above-mentioned sealing layer.

(Paper substrate)
The paper base of the release paper is flexible (for example, in a state where the release paper is attached to the coverlay film (referred to as an adhesive body), the adhesive body can be wound around a core such as a paper tube and stored. To a certain extent). On the other hand, as the name “base material” indicates, the paper base material has a strength that can guarantee the strength of the entire release paper. Specific examples of such a paper substrate include release paper base paper, high-quality paper, kraft paper, kulpack paper, foam paper, semi-bleached paper, glassine paper, and crepe paper.

  The paper substrate contains an appropriate amount of moisture in order to exhibit the flexibility and strength. The moisture content of the paper substrate is 1 to 10% by mass, preferably 1.5 to 8.0% by mass, more preferably 2.0 to 6.0% by mass, when the entire paper substrate is 100% by mass. %.

  The thickness of the paper substrate may be in the range of 40 to 300 μm, for example. In order to suppress the generation of wrinkles during the production of the release paper and in the patch, the lower limit of the thickness is preferably 50 μm. On the other hand, the upper limit of the thickness is preferably 150 μm in order to suppress an excessive increase in the amount of water contained in the paper base material and suppress surface roughening in the patch. The thickness of the paper substrate is measured according to JIS P8118.

(Medication layer)
As described in the background section, the filler layer is mainly used to prevent the components of the release agent layer from penetrating into the paper base during the application of the release agent. It is provided between the material layers. At the same time, the filler layer also plays a role of keeping the moisture of the paper substrate in the finished release paper constant. Here, the sealing layers provided on both surfaces of the paper base material may have the same composition or different compositions, and each of the sealing layers provided on one side of the paper base material is a single layer or It can be a multilayer structure.

  Among the sealing layers, the sealing layer in the case of being laminated in the order of the paper base material, the sealing layer, and the release agent layer is (a) from the release agent layer to the paper base material when the release agent is applied. And (b) moisture can be prevented from entering or leaving the paper substrate from the release agent layer side. As described above, the functions (a) and (b) of the sealing layer are caused by the properties of the single-layer sealing layer or the multilayer sealing layer. Among the above-mentioned sealing layers, when the paper base material and the sealing layer are laminated in this order (that is, the release agent layer is not laminated), the sealing layer is (c) the paper base material from the outside of the release paper. It is constituted by a single layer or multiple layers that can prevent moisture from entering or leaving (or from).

  Examples of the material for the sealing layer include materials that can perform the function (a) and / or (b) or the function (c). Specific examples of the material include polyolefin resins, preferably polyethylene resins. When the specific example is applied to the description in the immediately preceding paragraph, for example, each of the two sealing layers (single layer or multilayer) provided on both surfaces of the paper base is the same or different polyolefin resin (preferably May be constituted by a polyethylene-based resin).

(Polyolefin resin)
The polyolefin-based resin forming the eye stop layer is composed of one or more monomer units based on an olefin having 2 to 18 carbon atoms such as ethylene, propylene, 1-butene, 1-hexene, It is a polymer containing 50% by mass or more based on the total amount of the resin. Examples of the polyolefin resin include a polyethylene resin that is a polymer containing 50% by mass or more of monomer units based on ethylene, and a polypropylene resin that is a polymer containing 50% by mass or more of monomer units based on propylene. Etc. In the sealing layer, it is preferable to use a polyethylene resin as the polyolefin resin. The polyolefin resin may contain monomer units other than olefins. The eye-stopping layer can be formed of one or more polyolefin-based resins as long as there is no problem with the formation of the eye-stopping layer and the function. In the case where a multi-layered sealing layer is formed, the main component polyolefin used in each sealing layer can be the same or different.

  Examples of the polyethylene resin include ethylene homopolymers such as high-pressure method low-density polyethylene; monomer units based on ethylene (for example, low-pressure method high-density polyethylene), and α-olefins having 3 to 20 carbon atoms, An ethylene copolymer comprising at least one monomer unit (eg, ethylene-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-butene-1-hexene copolymer); ethylene -Vinyl carboxylate copolymer (for example, ethylene-vinyl acetate copolymer); Ethylene-unsaturated ester copolymer (ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, etc.) It is done. The polyethylene resin can be used alone or in combination of two or more, as long as there is no problem in the processing of the sealing layer.

The density of the polyethylene resin in the first stop layer, from the viewpoint of improving heat resistance, preferably 900 kg / ^{m 3} or more, more preferably 910 kg / ^{m 3} or more, more preferably 915 kg / ^{m 3} or more. The density is from the viewpoint of improving the adhesion between the paper substrate and the sealing layer, preferably 960 kg / ^{m 3} or less, more preferably 950 kg / ^{m 3} or less, more preferably 940 kg / ^{m 3} or less. When using 2 or more types of polyethylene-type resin for a combination sealing layer, it is preferable that the density of the mixture of 2 or more types of polyethylene-type resin is the said range. The value of the density of the mixture is a value of mass arithmetic average of the density indicated by each polyethylene resin.

  The polypropylene resin includes a propylene homopolymer; a monomer unit derived from propylene, and a monomer unit derived from at least one selected from α-olefins having 4 to 20 carbon atoms and ethylene. A propylene copolymer (propylene-ethylene copolymer, propylene-1-butene copolymer, propylene-1-hexene copolymer, propylene-ethylene-1-butene copolymer, propylene-ethylene-1- Hexene copolymer, etc.). The propylene copolymer is a random copolymer or a block copolymer. The polypropylene resin can be used alone or in combination of two or more, as long as there is no problem in processing the sealing layer.

  Each of the sealing layer (single layer or multilayer) may contain an additive as long as the effects of the present invention are not impaired. Examples of the additive include an anti-blocking agent, an antioxidant, a neutralizing agent, an antistatic agent, an antifogging agent, and a lubricant.

(Thickness of eye stop layer)
Although the thickness of each said sealing layer currently formed in both surfaces of the said paper base material is not specifically limited, For example, it is the range of 2-100 micrometers. The lower limit of the thickness is preferably 4 μm, more preferably 8 μm, from the viewpoint of suppressing the occurrence of pinholes. The upper limit of the thickness is preferably 50 μm, more preferably 40 μm, from the viewpoint of improving the state of the roll obtained by winding the completed release paper.

  The thickness of the sealing layer is, for example, by removing the paper fiber by washing the paper substrate part of a single-sided polylaminated paper (a paper substrate having only the sealing layer on one side) with a certain area, The mass of the release paper after drying and removing the paper substrate is measured (minimum unit: 1 mg), and the mass is calculated from the mass value and the resin density. In the case of double-sided polylaminated paper, the thickness of each eye stop layer can be determined by the above-mentioned method after separating into two at the paper base material to make single-sided polylaminated paper.

[Method for producing release paper]
One aspect of the present invention is a method for producing the release paper. The manufacturing method includes the amino alkyd resin and the epoxy resin, and applies the mixture containing no silicon-based compound to the sealing layer, and thermally cures the mixture at 115 to 140 ° C. A step of forming a release agent layer. Here, when the total amount of the amino alkyd resin and the epoxy resin contained in the mixture is 100% by mass, the mixture is 84.0-98.8% by mass of amino alkyd resin and 1.2-16. 0.0 mass% epoxy resin is contained. Furthermore, the amino alkyd resin comprises an amino resin and an alkyd resin in a mass ratio of 10:90 to 80:20. An outline of a manufacturing method according to some embodiments will be described below with reference to FIG.

(Composition of the mixture)
One of the features in the manufacturing method is the composition of the mixture. The mixture essentially contains an aminoalkyd resin and an epoxy resin as resin components. In particular, by including the epoxy resin in the above-mentioned proportion, the residual of the unreacted aminoalkyd resin in the release agent layer after the heat curing of the release agent applied to the sealing layer can be extremely reduced. . As shown in the following chemical formula, when an epoxy resin is present in the mixture, residual amine derived from the unreacted aminoalkyd resin can react with the epoxy moiety derived from the epoxy resin contained in the mixture. Because.

  For the above reasons, the release agent layer formed by thermosetting the mixture containing an epoxy resin hardly reacts with the components of the adhesive layer (for example, epoxy resin) in the cover lay film. . This reaction is the main cause of heavy peeling of the release paper from the coverlay film. Examples of conditions under which the reaction takes place include 2 weeks at 60 ° C. or 3 days at 100 ° C. In addition, the said example is an example of the acceleration conditions for test time shortening in the test which evaluates the state of the said sticking body, and is different from the conditions which actually handle a sticking body.

  The above mixture contains 84.0 to 98.8% by mass of aminoalkyd resin and 1.2 to 16.0% by mass of epoxy resin when the total amount of aminoalkyd resin and epoxy resin is 100% by mass. Yes. The content of the epoxy resin is preferably 1.2% by mass or more, more preferably 1.25% by mass or more, from the viewpoint of reliably preventing the unreacted aminoalkyd resin from remaining. The content is more preferably at least 1% by mass, and particularly preferably at least 1.35% by mass. Since the total amount of amino alkyd resin and epoxy resin is 100% by mass, from the same viewpoint, the content of amino alkyd resin in this case is preferably 98.8% by mass or less, and 98.75% by mass or less. It is more preferable that it is 98.7 mass% or less, and it is especially preferable that it is 98.65 mass% or less. On the other hand, the content of the epoxy resin is 16.0% by mass or less from the viewpoint of surely preventing residual unreacted epoxy resin after thermosetting (which can cause heavy peeling as well as residual amine). Preferably, it is 15.5% by mass or less, more preferably 15.0% by mass or less, and particularly preferably 14.5% by mass or less. Since the total amount of the amino alkyd resin and the epoxy resin is 100% by mass, from the same viewpoint, the content of the amino alkyd resin in this case is preferably 84.0% by mass or more, and 84.5% by mass or more. It is more preferable that it is 85.0 mass%, and it is especially preferable that it is 85.5 mass%.

  In one embodiment, the mixture contains only amino alkyd resin and epoxy resin as resin components. In other embodiment, the said mixture contains other resin as a resin component other than an amino alkyd resin and an epoxy resin. Details of the other resins will be described later.

  The content of the amino alkyd resin and the epoxy resin in the above mixture is such that the total number of amine groups of the amine compound remaining after thermal curing of the mixture not containing the epoxy resin is the epoxy group possessed by the epoxy resin. Can be selected to approximately match the total number of. The number of amine groups and epoxy groups in one molecule of amino alkyd resin and epoxy resin will be apparent by referring to specific examples of amino alkyd resin and epoxy resin described later.

(Amino alkyd resin)
An amino alkyd resin means a mixture containing an amino resin and an alkyd resin in an unreacted state. Specific examples of the amino resin and alkyd resin are described below, but not limited to a mixture of these specific examples, but any other amino alkyd resin such as a known amino alkyd resin may be used in the above mixture.

  Amino resin is a generic term for resins obtained by reacting aldehydes with amino groups of amino group-containing compounds (urea, melamine, aniline, sulfoamide, amino group-containing acrylic resins, etc.). For example, as the designation, an amino resin whose amino group-containing compound is urea is called urea resin, and an amino resin whose amino group-containing compound is melamine is called melamine resin. Examples of the amino resin include known resins, preferably melamine resins, more preferably butylated melamine resins or methylated melamine resins. Specific examples of the amino resin include Amidia (registered trademark) P-138, which is a butylated urea resin, and Amidia (registered trademark) J-820-60, which is a butylated melamine resin, provided by DIC Corporation. And Amidia (registered trademark) L-105-60, which is a methylated melamine resin.

  Alkyd resins include (1) polybasic acids (phthalic anhydride, maleic anhydride, etc.), (2) fatty acids (coconut oil, linseed oil, soybean oil, etc.), and (3) polyhydric alcohols (glycerin, trimethylol). Propane, pentaerythritol, etc.). As the alkyd resin, modified alkyd resins (such as rosin-modified alkyd resins modified with rosin or phenol, and phenol-modified alkyd resins) can be used. As specific examples of the alkyd resin, all are provided by DIC Corporation. Archidia (registered trademark) J-524-IM-60, Archidia (registered trademark) ER-3653-60, and the like.

  Amino alkyd resins prepared by mixing commercially available amino resins and alkyd resins may be used. Among the aminoalkyd resins prepared by mixing, a resin having a low surface free energy modified with a long-chain alkyl group is preferable from the viewpoint of the release property. Specific examples of the aminoalkyd resin include Tesfine (registered trademark) 303, Tesfine (registered trademark) 305, and Tesfine (registered trademark) 314, all of which are provided by Hitachi Chemical Co., Ltd.

  The amino alkyd resin comprises an amino resin and an alkyd resin in a mass ratio of 10:90 to 80:20. That is, the amino alkyd resin is composed of 10 to 80% by mass amino resin and 20 to 90% by mass alkyd resin when the total amount of amino resin and alkyd resin contained in the amino alkyd resin is 100% by mass. Contains. By setting the amino resin and the alkyd resin within the above mass ratio range, heavy peeling (especially heavy peeling at high temperature) can be suppressed over time. The amino alkyd resin is preferably from 12:88, more preferably from 15:85, and even more preferably from the viewpoint that the amino resin and the alkyd resin are hardly peeled off over time and the surface film curability is good. : 82 ~, and particularly preferably 20: 80 ~. The amino alkyd resin is preferably ˜78: 22, more preferably ˜75 from the viewpoint that the amino resin and the alkyd resin are not easily peeled off over time and the surface tension is high, so that peeling from the adhesive is facilitated. : 25, more preferably ~ 72: 28, particularly preferably ~ 70: 30. That is, the amino alkyd resin is preferably 12% by mass or more, more preferably 15% by mass or more, and still more preferably 18% when the total amount of amino resin and alkyd resin contained in the amino alkyd resin is 100% by mass. More than mass%, particularly preferably 20 mass% or more amino resin, and preferably 88 mass% or less, more preferably 85 mass% or less, still more preferably 82 mass% or less, particularly preferably 80 mass% or less. Contains. The amino alkyd resin is preferably 78% by mass or less, more preferably 75% by mass or less, and still more preferably 72% by mass, when the total amount of amino resin and alkyd resin contained in the amino alkyd resin is 100% by mass. Less than 70% by weight amino resin, particularly preferably 70% by weight or less amino resin, and preferably 22% by weight or more, more preferably 25% by weight or more, further preferably 28% by weight or more, particularly preferably 30% by weight or more alkyd resin. Contains.

  In one embodiment, when the total amount of amino resin and alkyd resin contained in the amino alkyd resin is 100% by mass, the amino alkyd resin is 10-50% by mass or 15-45% by mass amino resin, and 50-90 mass% or 55-85 mass% of alkyd resin may be included.

  An acid catalyst (curing agent) for curing the aminoalkyd resin may be added to the aminoalkyd resin. Examples of the acid catalyst include strong acids such as p-toluenesulfonic acid. The addition amount of the acid catalyst may be, for example, 2 to 10 parts by weight with respect to 100 parts by weight of the resin component.

(Epoxy resin)
The epoxy resin as a component of the above mixture is a monomer unit that contains two or more epoxy groups per molecule and polymerizes by thermosetting. Although the specific example of an epoxy resin is demonstrated below, other arbitrary epoxy resins, such as a well-known epoxy resin, can be used for the said mixture.

  Examples of epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, novolac type epoxy resins, cyclic aliphatic type epoxy resins, long chain aliphatic type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins. Etc.

  Specific examples of the bisphenol A type epoxy resin include jER (registered trademark) 825 (manufactured by Mitsubishi Chemical Corporation), EPICLON (registered trademark) 840 (manufactured by DIC Corporation), and the like. Specific examples of the bisphenol F type epoxy resin include jER (registered trademark) 806 (manufactured by Mitsubishi Chemical Corporation), YDF-170 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), and the like.

(Silicon compounds)
The silicon-based compound that should not be included in the mixture is, for example, a compound that can contaminate an adherend (for example, a substrate) to which the coverlay film is to be attached and cause poor conductivity in an electrical connection portion or the like of the adherend. . Specific examples of the silicon compound include silicone resin, silicone oil, silicone rubber, silicone adhesive, silane coupling agent, synthetic silica antiblocking agent, silica gel, diatomaceous earth, and the like.

(Other resins)
The mixture may contain any resin that does not interfere with the formation of the release agent layer except the amino alkyd resin and the epoxy resin (however, the silicon component is not included). Examples of such resins include phenolic resins and unsaturated polyester resins. The resin may be contained in an amount of, for example, 0.1 to 40% by mass with respect to the total amount of the resin components in the mixture.

  The mixture may contain any additive other than amino alkyd resin and epoxy resin that does not interfere with the formation of the release agent layer, etc. (however, it does not contain a silicon component). Examples of such additives include anti-blocking agents, antioxidants, neutralizing agents, antistatic agents, antifogging agents, lubricants and the like. The additive may be contained in an amount of, for example, 0.01 to 10% by mass with respect to the total amount of the resin components in the mixture.

(solvent)
The above mixture is a liquid material in which the above-described resin is dissolved or dispersed in a solvent. Examples of the solvent include conventionally known organic solvents that can appropriately dissolve or mix the above-described resin. Specific examples of the organic solvent include toluene and a toluene / ethyl acetate mixed solvent. The solvent can be present in the mixture at any concentration. The concentration can be determined, for example, according to the apparatus and method for applying the mixture. As an example, when the mixture is applied using a gravure coater, the resin concentration when the total amount of the mixture is 100% by mass may be 1 to 50% by mass. The concentration can be 40% by mass or less, preferably 30% by mass or less, from the viewpoint of preventing uneven application of the mixture to the filler layer, and from the viewpoint of saving energy necessary for volatilizing the solvent during thermal curing. It may be 1% by mass or more, preferably 5% by mass or more.

(Specific process examples)
Drawing 1 is a figure showing a process in a manufacturing method concerning two typical embodiments. FIG. 1 (a) shows an embodiment in which the mixture is thermally cured in a state in which one surface of the paper base is exposed (no sealing layer is formed on the surface), b) shows an embodiment in which the mixture is thermally cured in a state where both sides of the paper substrate are not exposed. In (a) and (b) of FIG. 1, S2 is not present in (a) in order to show S3 as a step of forming a release agent layer by thermosetting.

  As shown in FIG. 1 (a), the manufacturing method of a typical embodiment includes steps S1, S3, and S4. First, the sealing layer 3a is formed on the paper substrate 1 (S1). Next, the release agent layer 5 is formed by thermosetting the above-mentioned mixture coated on the sealing layer 3a (S3). Finally, the sealing layer 3b is formed on the exposed surface of the paper substrate 1 (S4). That is, S3 (formation of a release agent layer by thermosetting) is performed in a state where one of the paper base materials 1 is exposed. In S <b> 3, moisture partially evaporates from the paper substrate 1. However, since the heating temperature is 115 to 140 ° C., the amount of water vapor generated from the paper base material 1 is small, and one side of the paper base material 1 (the surface opposite to the surface with the sealing layer 3a) ) Is open. Therefore, the generated water vapor diffuses from the one surface of the paper substrate 1 and does not stay at the interface with the sealing layer 3a. Therefore, in S3 of (a), roughening of the surface of the release agent layer 5 that can be caused by the influence of water vapor and overheating of the material of the sealing layer 3a is suppressed. However, by supplementing the paper base material 1 with water at the end of S3, the end portion is less likely to curl in the final product, and the quality of the release paper can be improved.

  As shown in FIG. 1 (b), the manufacturing method of another representative embodiment includes steps S1, S2 and S3. First, the sealing layer 3b is formed on the paper substrate 1 (S1). Next, the sealing layer 3a is formed on the surface opposite to the sealing layer 3b (S2). Finally, the release agent layer 5 is formed by thermally curing the mixture coated on the sealing layer 3a (S3). In S3, the amount of generated water vapor is small, and the surface of the formed release agent layer 5 is not roughened, as in S3 of (a). In particular, in the case of (b), the paper base material 1 does not lose moisture in S3, and the end part is difficult to curl in the final product without extra processing, so the quality of the release paper is high.

  Details of each step in the manufacturing method showing two typical examples using FIG. 1 will be described below.

(Application of the mixture to the filler layer)
Examples of the method for applying the mixture to the sealing layer 3a include coating using a roll coater, a gravure coater, a die coater, a knife coater, a chamber doctor, a Mayer bar coater, a comma coater, and the like.

The coating amount of the mixture is preferably 0.1 to 3.0 g / ^{m 2,} in order to prevent uneven coating, more preferably 0.2 g / ^{m 2} or more, to sufficiently cure the mixture Therefore, it is more preferably 2.0 g / m ² or less. The coating amount of the mixture is the coating amount after removing the solvent.

  The coating amount of the mixture can be determined from the change in weight before and after the release agent coating. Also, based on the coating amount in advance and the spectral height of the aminoalkyd resin intrinsic functional group (the intrinsic functional group varies depending on the type of raw material used) in surface infrared spectroscopy (ATR method FT-IR), If a calibration curve is prepared, the coating amount of the mixture can be determined more easily.

(Thermosetting of the mixture)
The release agent layer 5 is formed by thermally curing the mixture applied to the sealing layer 3a. The heating temperature in the said thermosetting is 115-140 degreeC. The lower limit of the heating temperature is 115 ° C., preferably 117 ° C., from the viewpoint of preventing heavy peeling by sufficiently reacting the aminoalkyd resin and the epoxy resin in the mixture. The upper limit of the heating temperature is to keep the surface of the release paper smooth (for example, to prevent unevenness (roughening) from occurring in the sealing layers 3a and 3b) and to keep the release paper itself flat (the release paper is From the viewpoint of preventing curling, the temperature is 140 ° C., preferably 135 ° C., more preferably 130 ° C., and still more preferably 125 ° C. The heating temperature means the temperature in the atmosphere inside the oven or the like. Although the heating time of the said mixture changes with kinds of equipment which implements thermosetting, it is 2 to 90 seconds, for example, when using a small oven, it uses equipment in a production line for 20 to 90 seconds. In some cases it can be 2-20 seconds. Here, the heating time in the oven equipment incorporated in a part of the production line means a time for the mixture to pass through a part of the production line at the heating temperature. The solvent component in the mixture is volatilized by setting the partial pre-stage to a temperature condition of around 100 ° C., so the heating time using the heating temperature is shortened in the production line compared to a small oven. obtain.

(Lamination of sealing layers 3a and 3b on paper substrate 1)
The method for laminating the sealing layers 3a and 3b on the paper substrate 1 is not particularly limited, and any method can be used. Examples of the method include an extrusion laminating method, a dry laminating method, a wet laminating method and the like, and among them, the extrusion laminating method is preferable.

  A commercially available apparatus can be used for the extrusion laminating method. When the sealing layers 3a and 3b are formed of a polyethylene-based resin, the processing temperature is preferably selected from a range of 250 to 360 ° C. The lower limit of the above range is 250 ° C., preferably 280 ° C., more preferably 300 ° C., from the viewpoint of improving the adhesion between the paper substrate 1 and the sealing layers 3a and 3b. The upper limit of the above range is 360 ° C., preferably 350 ° C., more preferably 340 ° C., from the viewpoint of suppressing the decomposition of the polyethylene resin. The processing temperature is a value obtained by measuring the molten resin temperature of the resin extruded from the T die using a non-contact thermometer (for example, Thermogear G100, manufactured by NEC Avio Infrared Technology Co., Ltd.) immediately below the T die. . Further, the processing speed is preferably 50 m / min or more, more preferably 100 m / min or more from the viewpoint of increasing production efficiency, and the viewpoint of improving the adhesion between the paper substrate 1 and the sealing layers 3a and 3b. Therefore, it is preferably 600 m / min or less, more preferably 300 m / min or less.

  In addition, in order to improve the adhesive strength between the paper base material 1 and the sealing layers 3a and 3b, various surface treatments can be performed on the respective surfaces of the paper base material 1 that are brought into contact with the sealing layers 3a and 3b. The surface treatment can be appropriately selected from corona discharge treatment, flame (flame) treatment, and the like. The surface treatment for the paper substrate 1 can be performed in advance as a separate process from the lamination of the sealing layers 3a and 3b. It is preferable to carry out in-line immediately before lamination of the sealing layers 3a and 3b because it is more effective. Moreover, the adhesion strength between the paper base material 1 and the sealing layers 3a and 3b can also be improved by oxidizing the surface of the molten polyolefin layer (sealing layers 3a and 3b before lamination) on the side in contact with the paper base material 1. Can be improved. As an example of the surface oxidation treatment, a treatment (ozone treatment) of blowing air containing ozone can be directly applied to the surface of the molten polyolefin layer. Alternatively, immediately before the paper base material 1 and the molten polyolefin layer are pressure-bonded, the surface of the paper base material 1 on the side in contact with the molten polyolefin layer can be subjected to ozone treatment. At this time, as a result of the ozone treatment, ozone is applied to the surface of the paper substrate 1, and the molten polyolefin layer is oxidized by the ozone. Each of the surface treatments for either the paper substrate 1 and the molten polyolefin layer can be combined and performed multiple times.

  As described above, the sealing layers 3 a and 3 b may have a multilayer structure that is formed independently on both sides of the paper substrate 1. Examples of methods for forming the sealing layers 3a and 3b having a multilayer structure include a method of combining a plurality of extruders and a single T die (coextrusion laminator), a plurality of single layer laminators or a coextrusion laminator The method of laminating using is mentioned. The forming method may be a method in which these exemplified methods are combined in an arbitrary number. For example, in a method of combining a plurality of single-layer laminators, all layers can be formed simultaneously in a single production line, or a paper substrate after forming a part of a multilayer structure in a certain production line is wound once. Can be deployed in other production lines, and the remainder of the multilayer structure can be further laminated. That is, in the multi-layer structure in the sealing layers 3a and 3b, the layer that is in direct contact with the paper base 1 and the other layers (for example, the layer farthest from the paper base 1) are formed simultaneously. Or formed independently. It is preferable to form all the layers constituting the sealing layers 3a and 3b at the same time (in a single production line) from the viewpoint of manufacturing simplicity.

  In one embodiment, the step of laminating is a step of laminating a filler layer on each of the one surface of the paper base and the surface on the back side of the surface, and the step of forming is a step of laminating the paper. This is a step of forming a release agent layer by thermosetting the mixture applied only to the sealing layer laminated on the one surface of the substrate.

(Physical properties of release paper)
The release paper produced by the above production method can exhibit the following physical properties.

(Peeling load and measuring method)
The peeling load of the release paper may vary depending on the type of coverlay film to be attached. However, since it is generally known that a problem arises when the peel load is too large, a smaller peel load is preferable. The problem is, for example, that it is difficult to feed out the release paper that is wound up in a roll shape when affixing to the coverlay film, and that the coverlay film is affixed for protection until then. For example, the base material of the coverlay film is damaged by requiring a strong force to peel off the release paper. The peeling load can be measured, for example, by the following method.

  The peeling load of the release paper applied to the FPC board application or the like can be measured in the following state. First, as a part constituting a part of the FPC board, an epoxy thermosetting adhesive is applied to the surface of a cover lay film substrate (polyimide film or polyester film), and the adhesive is subjected to predetermined heating conditions. A dried layer is formed. After the formed product bonded by thermocompression bonding of the release paper (the release agent layer) to the layer under a predetermined condition is cured and stored under a predetermined temperature condition, the peeling load of the formed product is measured. Alternatively, as the part, a film obtained by peeling off a release paper attached to a coverlay film with an epoxy adhesive for a commercially available FPC board can be used. Examples of the commercially available coverlay film with an epoxy adhesive for an FPC board include Nikaflex (registered trademark) series (manufactured by Nikkan Kogyo Co., Ltd.). The release paper produced by the above production method may have a small peel load as shown in the examples described later.

(Surface tension measurement method)
As a more general method for evaluating peelability without considering the combination of the release paper and the coverlay film, there is a method of measuring the surface tension of the release paper. A higher surface tension is preferable because peeling from the adhesive is facilitated. Examples of methods for measuring the surface tension of the release paper include a contact angle method, a wetting tension test method, and an oil-based ink repelling method. The release paper produced by the above production method may have a large surface tension measured by the oil-based ink repelling method, as shown in the examples described later.

(Appearance evaluation of release paper)
The quality is evaluated by visually observing the appearance of the surface of the release agent layer 5 in the release paper. When the release paper is peeled from the coverlay film, the unevenness generated on the surface of the release agent layer 5 physically grasps the adhesive of the coverlay film and partially peels it off. In this case, since the adhesiveness of the cover lay film to be protected is impaired (which hinders the subsequent process), the release paper does not play its original role. Further, the unevenness generated in the release agent layer 5 is transferred to the surface of the adhesive of the cover lay film. When the metal foil is bonded to the cover lay film, the unevenness transferred to the adhesive causes the entrapment of bubbles between the cover lay film and the metal foil, thereby providing the product having the cover lay film. Make it bad. Accordingly, the surface appearance of the release agent layer 5 is preferably excellent in smoothness. The release paper produced by the above production method can have an excellent surface appearance and smoothness as shown in the examples described later.

(Surface coating curability)
The smaller the unreacted resin component remaining in the release agent layer 5, the better the surface film curability. When a large amount of unreacted resin component remains in the release agent layer 5, the resin is dissolved in an organic solvent contained in the adhesive layer of the coverlay film or reacts with the adhesive component. The peeling load can be increased and various problems can occur.

  The surface coating curability can be evaluated by rubbing the surface of the release paper a predetermined number of times (rubbing test) with absorbent cotton soaked in an organic solvent such as toluene. The release paper subjected to the rubbing test does not change the surface when the surface coating curability is good, and causes roughening and breakage of the surface when the surface coating curability is poor. The release paper produced by the above production method can have good surface film curability as shown in the examples described later.

(Example of using release paper)
The release paper can be used in various applications. In one embodiment, it is used for electronic materials such as an FPC board, and for example, an adhesive surface of a coverlay film constituting a part of the FPC board is protected. The adhesive layer on the adhesive surface of the coverlay film may include, for example, an epoxy resin. Alternatively, the release paper may be used for other adhesive sheets. The other adhesive sheet may include, for example, an epoxy resin. The other adhesive sheet may be an adhesive sheet for a flexible printed circuit board. In one Embodiment, the said release paper protects the said adhesive bond layer by affixing on the adhesive bond layer containing an epoxy resin. Moreover, the said adhesive bond layer may comprise some flexible printed circuit boards.

  Examples will be shown below to describe the embodiments of the present invention in more detail. Of course, the present invention is not limited to the following examples, and it goes without saying that various aspects are possible in detail. Further, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims, and the present invention is also applied to the embodiments obtained by appropriately combining the disclosed technical means. It is included in the technical scope of the invention. Moreover, all the literatures described in this specification are used as reference.

  As examples and comparative examples, the physical properties of each prepared release paper (manufacturing conditions will be described later) were measured as follows.

(1) Measurement of peeling load (unit: N / m) A release paper (referred to as a test object in order to avoid confusion with other release paper) is cut to a size of 182 mm × 257 mm (B5 size) and tested. The surface of the object coated with the release agent was placed on the hot plate heated to 80 ° C. for 5 seconds. The release paper affixed to the polyimide base material coverlay film (Nikaflex (registered trademark) CISV2535, manufactured by Nikkan Kogyo Co., Ltd., polyimide film thickness: 25 μm, adhesive thickness: 35 μm) was peeled off. The surface of the polyimide substrate coverlay film from which the release paper was peeled off (adhesive surface) was placed on the test object placed on the hot plate. From above the film and the test object, a 2 kgf rubber roller was reciprocated twice over 5 seconds and pressed to prepare a test piece.

The test piece was sandwiched between two glass plates, a load of 4.0 kgf (pressure: 1.96 kPa) was applied, and the test piece was stored in an oven at 100 ° C. for 3 days. Then, after curing at 23 ° C. and 65% RH for 1 hour or longer, the peeling load was measured under the following conditions using a high-speed peeling tester TE-701 (manufactured by Tester Sangyo Co., Ltd.). The results shown in Table 1, Table 3, and Table 4 are average values of values obtained from three test pieces. In addition, it is so preferable that the value of peeling load is small.
Tensile speed: 0.3 m / min Peel angle: 180 °.

(2) Evaluation of oil-based ink repellency The test object was cut into a size of 15 cm × 15 cm, and an oil-based writing instrument (Magic Ink (registered trademark) Gokuta (manufactured by Teranishi Chemical Industry Co., Ltd., color name: black) was formed on the surface of the release agent layer. , Line width: 18 mm)), a line having a width of 18 mm and a length of about 12 cm was drawn. Three minutes after drawing the line, the ink was visually observed and evaluated according to the following criteria.
○: Repel the oil-based ink and the underlying release paper looks like dots. ×: Does not repel the oil-based ink.

(3) Appearance Evaluation The surface of the release agent layer to be tested was evaluated by the following criteria by visual observation under oblique light (light was applied to the test object and observed from an oblique direction) under a fluorescent lamp.
○: The surface is smooth and glossy. ×: The surface is roughened and rough, and the glossiness is inferior.

(4) Surface coating curability evaluation A cotton ball (silky cotton ball No. 14 (diameter: about 14 mm), White Cross Co., Ltd.) obtained by cutting a test object into a size of 15 cm × 15 cm and sucking about 0.8 g of toluene. The release agent layer to be tested was rubbed over a length of about 10 cm using finger pressure. The surface of the test object after rubbing was visually evaluated according to the following criteria.
○: The surface remains smooth and does not change. ×: The surface is roughened and rough, and the glossiness is inferior.

[Preparation of amino alkyd resin solution]
12.0 g of Archidia J-524-IM-60 (manufactured by DIC Corporation, solid concentration 60%) as the alkyd resin, 8.0 g of Amidia L-105-60 (manufactured by DIC Corporation, solid concentration) as the amino resin 60%), 48.57 g of ethyl acetate as a solvent was added and stirred, 0.72 g of a dryer 900 (manufactured by Hitachi Chemical Co., Ltd.) was further added as a curing agent, paratoluenesulfonic acid, and stirred, and 17.5 masses. % (Resin solid concentration) of amino alkyd resin solution was obtained. The solid content mass ratio of amino resin: alkyd resin in the amino alkyd resin solution was 40:60.

[Production of double-sided polylaminated paper]
Using a two-layer coextrusion laminator (manufactured by Sumitomo Heavy Industries Modern, Ltd., resin temperature: 320 ° C., processing speed: 140 m / min), two layers of the same kind on the one side (side A) of the paper substrate (Total thickness of two layers: 17 μm) was laminated.
Paper base: fine paper, thickness 80μm
Eye stop layer: High-pressure low-density polyethylene (manufactured by Sumitomo Chemical Co., Ltd.) (density: 919 kg / m ³ ).
Next, using the two-layer coextrusion laminator, the same type of two sealing layers (total thickness of two layers: 17 μm) is stacked on the opposite surface (B surface) of the surface on which the sealing layers have been previously stacked. Thus, a double-sided polylaminated paper was produced.

[Example 1]
The release agent solution was coated on the B side of the double-sided polylaminated paper using a Mayer bar coater. In the release agent solution, an amino alkyd resin solution and a bisphenol F type epoxy resin (YDF-170, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., epoxy resin 100 at a ratio of 98.0: 2.0 (mass ratio of contained resin). % By mass).

By heating the double-sided polylaminated paper coated with the release agent solution in a 120 ° C hot air oven (Safety Oven SPH (H) -202 manufactured by Espec Corp.) for 30 seconds, the organic solvent is removed and the release agent is cured. Release paper was obtained. The coating amount of the release agent after curing was 0.82 g / m ² (mass after removing the solvent per unit area). Table 1 shows the physical property values of the obtained release paper.

[Example 2]
A release paper was produced under the same conditions as in Example 1 except that the mass ratio of the resin contained in the release agent was changed to aminoalkyd resin: epoxy resin = 90.6: 9.4. The coating amount was 0.88 g / m ² . Table 1 shows the physical property values of the obtained release paper.

[Comparative Example 1]
A release paper was produced under the same conditions as in Example 1 except that the mass ratio of the resin contained in the release agent was changed to aminoalkyd resin: epoxy resin = 99.0: 1.0. The coating amount was 0.81 g / m ² . Table 1 shows the physical property values of the obtained release paper.

[Comparative Example 2]
A release paper was produced under the same conditions as in Example 1 except that the mass ratio of the resin contained in the release agent was changed to aminoalkyd resin: epoxy resin = 82.8: 17.2. The coating amount was 0.94 g / m ² . Table 1 shows the physical property values of the obtained release paper.

[Comparative Example 3]
A release paper was produced under the same conditions as in Example 1 except that the temperature of the hot air oven was changed to 110 ° C. The coating amount was 0.82 g / m ² . Table 1 shows the physical property values of the obtained release paper.

[Comparative Example 4]
A release paper was produced under the same conditions as in Comparative Example 3 except that the mass ratio of the resin contained in the release agent was changed to aminoalkyd resin: epoxy resin = 90.6: 9.4. The coating amount was 0.88 g / m ² . Table 1 shows the physical property values of the obtained release paper.

[Comparative Example 5]
A release paper was produced under the same conditions as in Example 1 except that the temperature of the hot air oven was changed to 150 ° C. The coating amount was 0.82 g / m ² . Table 1 shows the physical property values of the obtained release paper.

[Comparative Example 6]
A release paper was produced under the same conditions as in Comparative Example 5 except that the mass ratio of the resin contained in the release agent was changed to aminoalkyd resin: epoxy resin = 90.6: 9.4. The coating amount was 0.88 g / m ² . Table 1 shows the physical property values of the obtained release paper.

  Table 2 shows the change in peel load (N / m) based on the difference in heating temperature and epoxy resin content in the above examples and comparative examples. In Table 2, the letters “actual” and “ratio” represent examples and comparative examples, respectively.

Example 3
Using a two-layer coextrusion laminator (manufactured by Sumitomo Heavy Industries Modern Co., Ltd., resin temperature: 320 ° C., processing speed: 150 m / min), two layers of the same kind on the one side (A surface) of the paper substrate (Total thickness of two layers: 22 μm) was laminated.
Paper base: fine paper, thickness 70μm
A-side sealing layer: high-pressure low-density polyethylene (manufactured by Sumitomo Chemical Co., Ltd.) (density: 919 kg / m ³ ).
Using an in-line gravure coater, coating the release agent solution prepared in amino alkyd resin: epoxy resin = 97.0: 3.0 on the A-side sealing layer of the single-sided polylaminated paper at a processing speed of 150 m / min. Further, the organic solvent was removed by heating in a hot air oven (continuously 100 ° C./4 seconds, 130 ° C./6 seconds, 110 ° C./4 seconds), and the release agent was cured. The coating amount of the release agent after curing was 0.44 g / m ² (mass after removing the solvent per unit area). In addition, the solid content mass ratio of amino resin: alkyd resin of the amino alkyd resin used was 40:60.
Next, the sealing layer was laminated on the B surface under the same processing conditions as those of the A surface except that the thickness of the sealing layer was 15 μm and the processing speed was 100 m / min, to obtain a release paper. Table 3 shows the physical property values of the obtained release paper.

Example 4
Peeling is performed under the same conditions as in Example 1 except that the mass ratio of the resin contained in the release agent is changed to amino alkyd resin: epoxy resin = 85.0: 15.0 and the temperature of the hot air oven is changed to 135 ° C. Paper was made. The coating amount was 0.92 g / m ² . Table 3 shows the physical property values of the obtained release paper.

  As is apparent from Tables 1 to 3, a release paper exhibiting good properties could be produced by appropriately selecting the amount of the epoxy resin contained in the release agent and the thermosetting conditions of the release agent. .

[Comparative Example 7]
The mass ratio of amino resin: alkyd resin in the amino alkyd resin solution was changed to 1:99, and the mass ratio of the resin contained in the release agent was changed to amino alkyd resin: epoxy resin = 90.0: 10.0. A release paper was produced under the same conditions as in Example 1 except that. The coating amount was 0.88 g / m ² . Table 4 shows the physical property values of the obtained release paper.

Example 5
The mass ratio of amino resin: alkyd resin in the amino alkyd resin solution was changed to 20:80, and the mass ratio of the resin contained in the release agent was changed to amino alkyd resin: epoxy resin = 90.0: 10.0. A release paper was produced under the same conditions as in Example 1 except that the temperature of the hot air oven was changed to 125 ° C. The coating amount was 0.88 g / m ² . Table 4 shows the physical property values of the obtained release paper.

Example 6
The mass ratio of amino resin: alkyd resin in the amino alkyd resin solution was changed to 50:50, and the mass ratio of the resin contained in the release agent was changed to amino alkyd resin: epoxy resin = 90.0: 10.0. A release paper was produced under the same conditions as in Example 1 except that. The coating amount was 0.88 g / m ² . Table 4 shows the physical property values of the obtained release paper.

Example 7
The mass ratio of amino resin: alkyd resin in the amino alkyd resin solution was changed to 70:30, and the mass ratio of the resin contained in the release agent was changed to amino alkyd resin: epoxy resin = 90.0: 10.0. A release paper was produced under the same conditions as in Example 1 except that. The coating amount was 0.88 g / m ² . Table 4 shows the physical property values of the obtained release paper.

[Comparative Example 8]
The solid content mass ratio of the amino resin: alkyd resin in the amino alkyd resin solution was changed to 100: 0, and the mass ratio of the resin contained in the release agent was changed to amino (alkyd) resin: epoxy resin = 90.0: 10.0. The release paper was produced under the same conditions as in Example 1 except that the temperature of the hot air oven was changed to 125 ° C. The coating amount was 0.88 g / m ² . Table 4 shows the physical property values of the obtained release paper.

  As is apparent from Table 4, a release paper exhibiting good properties could be produced by appropriately selecting the mass ratio of amino resin to alkyd resin in the amino alkyd resin.

  The present invention can be used in the field of producing release paper.

1 Paper base material 3a Sealing layer 3b Sealing layer 5 Release agent layer

Claims (5)

A release paper comprising a paper base material, a sealing layer and a release agent layer, and the release agent layer is laminated on the eye seal layer laminated on at least one surface of the paper base material A manufacturing method of
A step of laminating the eye stop layer on at least one surface of the paper base material, and applying a mixture containing an aminoalkyd resin and an epoxy resin and not containing a silicon compound to the eye stop layer; and Including heat-curing the mixture at 115 to 140 ° C. to form the release agent layer,
When the total amount of the amino alkyd resin and the epoxy resin contained in the mixture is 100% by mass, the mixture is 84.0 to 98.8% by mass of amino alkyd resin and 1.2 to 16.0% by mass. % Epoxy resin,
The said amino alkyd resin is a manufacturing method of a release paper which comprises an amino resin and an alkyd resin by mass ratio of 10: 90-80: 20. The step of laminating is a step of laminating a filler layer on each of the one surface of the paper base and the surface on the back side of the surface,
The step of forming is a step of forming a release agent layer by thermally curing the mixture that is applied only to the sealing layer laminated on the one surface of the paper substrate. The manufacturing method of the release paper of Claim 1.   The said mixture is a manufacturing method of the release paper of Claim 1 or 2 which contains only the said amino alkyd resin and an epoxy resin as resin.   The said release paper is a manufacturing method of the release paper of any one of Claims 1-3 which protects the said adhesive bond layer by affixing on the adhesive bond layer containing an epoxy resin.   The said adhesive bond layer is a manufacturing method of the release paper of Claim 4 which comprises some flexible printed circuit boards.

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