JP2021098802A - Coating agent and release paper base paper using the same, and release paper - Google Patents

Abstract

To provide a coating agent and a release paper base paper which are excellent in filling property of silicone, can suppress acid corrosion of a coating machine, promote curing of silicone of a release layer, and can improve adhesion between the base material and the release layer.SOLUTION: A coating agent contains modified PVA (A) and sodium acetate. The modified PVA (A) has a degree of saponification of 68 mol% or more and less than 99.9 mol% and a degree of viscosity average polymerization of 200 or more and less than 5,000, and has a double bond derived from an esterification agent of 0.01 mol% or more and less than 0.50 mol% in its side chain. The esterification agent is a carboxylic acid having a carbon-carbon double bond and/or its derivative. A peak width W0.05h at a height position of 5% from a base line at a peak measured by HPLC is 2.85 minutes or more and less than 3.70 minutes. A content of the sodium acetate is 0.01 pts.mass or more and 10 pts.mass or less with respect to 100 pts.mass of the modified PVA (A).SELECTED DRAWING: None

Description

In the present disclosure, a modified vinyl alcohol-based weight having a specific degree of saponification and a specific degree of viscosity average polymerization, a specific modifying group in the side chain, and a specific peak width when measured by high performance liquid chromatography. The present invention relates to a release paper base paper obtained by applying a coating agent containing coalescence (A) and sodium acetate to a base material, and a method for producing the same. The present disclosure also relates to a release paper having a release layer formed on the surface of the release paper base paper.

Polyvinyl alcohol (hereinafter, may be abbreviated as "PVA") is a unique synthetic polymer having hydrophilicity and crystallinity, and in the paper field, it is a paper strength enhancer, a dispersant for fluorescent white pigments, and an inorganic substance (hereinafter, abbreviated as "PVA"). It is used as a binder for calcium carbonate, clay, silica, etc.). Further, since PVA is excellent in film-forming property, it is possible to impart barrier property and oil resistance to gas and the like by applying it to paper.

Paper coated with PVA may be used as a barrier paper, and a typical example of the barrier paper is a release paper base paper. The release paper base paper is usually produced by applying PVA to the surface of a cellulose base material. Then, a release paper is obtained by forming a release layer (silicone layer) on the surface of the release paper base paper. PVA in release paper plays the role of a sealant that suppresses the penetration of expensive silicone or platinum into the substrate. Recently, in addition to such sealing properties, there is a demand for a release paper base paper capable of accelerating the curing of silicone in the release layer and improving the adhesion between the PVA layer and the silicone layer.

Patent Document 1 describes a release paper base paper coated with PVA having a silyl group satisfying a specific condition. Patent Document 2 describes a cellulose base material coated with PVA in which a double bond is introduced into a side chain by an acetalization reaction.

Japanese Unexamined Patent Publication No. 2005-194672 Japanese Patent Application Laid-Open No. 2013-531136

However, PVA of Patent Document 1 is insufficient in the effect of accelerating the curing of silicone and the effect of improving the adhesion between the base material and the silicone layer. Since the acetalization reaction used in Patent Document 2 usually uses a highly volatile acid such as hydrochloric acid or nitric acid, if such an acid remains in the acetalized PVA, it causes corrosion of equipment in the coating process. Therefore, improvement was desired. In addition, the effect of accelerating the curing of the silicone in the release layer was insufficient. Further, in Patent Documents 1 and 2, the storage stability of the coating agent after long-term storage has not been examined. Further, when the pH of the coating agent is too low, corrosion of the coating machine using the coating agent has become a problem.

This disclosure has been made in order to solve the above problems, and it is possible to suppress acid corrosion of a coating machine, and when it is applied to a release paper base paper, it is excellent in sealing property of silicone, and the silicone of the release layer is cured. It is an object of the present invention to provide a coating agent capable of promoting adhesion between a base material and a release layer, and a release paper base paper using the same. Another object of the present disclosure is to provide a release paper obtained by using the release paper base paper.

As a result of intensive research to solve the above problems, the present inventors have a specific range of saponification degree and viscosity average degree of polymerization, and also have a specific modifying group in the side chain, and perform high performance liquid chromatography. It was found that the above-mentioned problems could be solved by using a coating agent containing a modified vinyl alcoholic polymer (A) having a specific peak width and sodium acetate when measured in (1), and further research was carried out based on this finding. , The present invention has been completed.

That is, the present disclosure includes the following inventions.
[1] The modified vinyl alcohol-based polymer (A) and sodium acetate are contained, and the modified vinyl alcohol-based polymer (A) has a degree of esterification of 68 mol% or more and less than 99.9 mol%, and a viscosity average degree of polymerization. Is 200 or more and less than 5000, and the side chain has a double bond derived from an esterifying agent of 0.01 mol% or more and less than 0.50 mol%, and the esterifying agent has a carbon-carbon double bond. _{And / or a derivative thereof, the peak width W 0.05h} at a height of 5% from the baseline at the peak measured by high-speed liquid chromatography is 2.85 minutes or more and less than 3.70 minutes.
A coating agent having a sodium acetate content of 0.01 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the modified vinyl alcohol polymer (A).
[2] The esterifying agent is at least one selected from the group consisting of an aliphatic unsaturated monocarboxylic acid and / or a derivative thereof, and an aliphatic unsaturated dicarboxylic acid and / or a derivative thereof, according to [1]. The coating agent described.
[3] The esterifying agent includes an aliphatic unsaturated monocarboxylic acid having one carbon-carbon double bond and / or a derivative thereof, and an aliphatic unsaturated dicarboxylic acid having one carbon-carbon double bond. / Or the coating agent according to [1], which is one or more selected from the group consisting of derivatives thereof.
[4] The esterifying agent is at least one selected from the group consisting of (i) itaconic acid and / or a derivative thereof, and (ii) (meth) acrylic acid and / or a derivative thereof, according to [1]. The coating agent described.
[5] The modified vinyl alcohol-based polymer (A) further has an ethylene unit in the main chain, and the content of the ethylene unit is 1 with respect to all the monomer units of the modified vinyl alcohol-based polymer (A). The coating agent according to any one of [1] to [4], which is mol% or more and 10 mol% or less.
[6] The coating agent according to any one of [1] to [5], wherein the degree of saponification of the modified vinyl alcohol polymer (A) is 72 mol% or more and less than 99.0 mol%.
[7] In the peak measured by high performance liquid chromatography of the modified vinyl alcohol polymer (A), the peak width W _0.05h at a height of 5% from the baseline is 2.99 minutes or more and 3.40. The coating agent according to any one of [1] to [6], which is less than a minute.
[8] A release paper base paper obtained by applying the coating agent according to any one of [1] to [7] to a base material.
[9] The release paper base paper according to [8], wherein the base material is at least one selected from the group consisting of high-quality paper, medium-quality paper, alkaline paper, glassin paper, semi-glassin paper, paperboard, and white paperboard. ..
[10] A release paper having the release paper base paper according to [8] or [9] and a release layer formed on the surface of the release paper base paper.
[11] The release layer contains addition type silicone (C) and platinum (D), and the content of platinum (D) is 0.001 part by mass or more with respect to 100 parts by mass of addition type silicone (C). The release paper according to [10], which is 0.05 part by mass or less.

According to the present disclosure, acid corrosion of a coating machine can be suppressed, silicone is excellently sealed when coated on a release paper base paper, curing of the silicone in the release layer is promoted, and the base material and the release layer are released. It is possible to provide a coating agent capable of improving adhesion to and a release paper base paper using the same. Further, according to the present disclosure, it is possible to provide a release paper obtained by using the release paper base paper.

The coating agent of the present disclosure contains a modified vinyl alcohol-based polymer (A) and sodium acetate, and the modified vinyl alcohol-based polymer (A) has a degree of esterification of 68 mol% or more and less than 99.9 mol%. The viscosity average degree of polymerization is 200 or more and less than 5000, the side chain has 0.01 mol% or more and less than 0.50 mol% of double bonds derived from the esterifying agent, and the esterifying agent is a carbon-carbon double bond. _{A carboxylic acid and / or a derivative thereof having a peak width W 0.05h} at a height of 5% from the baseline at a peak measured by high-speed liquid chromatography of 2.85 minutes or more and less than 3.70 minutes. The content of sodium acetate is 0.01 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the modified vinyl alcohol polymer (A). The coating agent of the present disclosure can be particularly preferably used as a paper coating agent.

In the present specification, the upper limit value and the lower limit value of the numerical range (content of each component, parameter (for example, W _0.05h ), value calculated from each component, each physical property, etc.) can be appropriately combined.

[Modified vinyl alcohol polymer (A)]
The modified vinyl alcohol-based polymer (A) of the present disclosure (hereinafter, may be abbreviated as "modified PVA (A)") has a degree of esterification of 68 mol% or more and less than 99.9 mol%, and has a viscosity average polymerization. A carboxylic acid having a degree of 200 or more and less than 5000, having an esterifying agent-derived double bond in the side chain of 0.01 mol% or more and less than 0.50 mol%, and the esterifying agent having a carbon-carbon double bond. _{An acid and / or a derivative thereof, which has a peak width W 0.05 h} at a height of 5% from the baseline at a peak measured by high performance liquid chromatography (hereinafter, may be abbreviated as “HPLC”). It is 2.85 minutes or more and less than 3.70 minutes.

It is important that the viscosity average degree of polymerization of the modified PVA (A) is 200 or more and less than 5000. The lower limit of the viscosity average degree of polymerization is preferably 300 or more, more preferably 400 or more, further preferably 500 or more, and from the viewpoint of improving the adhesion between the base material and the release layer, 600 or more, 700 or more, 900 or more. In some cases, 1100 or more or 1300 or more is preferable. The upper limit of the viscosity average degree of polymerization is preferably less than 4500, more preferably less than 4300, further preferably less than 4000, and less than 3800, less than 3500, less than 3300 from the viewpoint of reducing the water-insoluble content of the modified PVA (A). Less than 3000, less than 2800 or less than 2700 may be preferred. When the viscosity average degree of polymerization is less than 200, the productivity is low and the water-insoluble content of the modified PVA (A) is high. Further, when used as a paper coating agent, the storage stability is lowered, the curing of the silicone is inferior, and the adhesion between the base material and the release layer is lowered. On the other hand, when the viscosity average degree of polymerization is 5000 or more, the water-insoluble content of the modified PVA (A) increases, the silicone is inferior in curing when used as a paper coating agent, and the base material and the release layer are separated from each other. Adhesion is reduced.

The viscosity average degree of polymerization of the modified PVA (A) is a value obtained by measuring according to JIS K 6726: 1994. Specifically, when the degree of saponification is less than 99.5 mol%, the modified PVA (A) saponified to a degree of saponification of 99.5 mol% or more is subjected to the ultimate viscosity [η] measured at 30 ° C. in water. ] (L / g) is used to determine the viscosity average degree of polymerization (P) by the following formula.
P = ([η] × 10 ⁴ / 8.29) ^{(1 / 0.62)}

It is important that the saponification degree of the modified PVA (A) is 68 mol% or more and less than 99.9 mol%. The lower limit of the saponification degree is preferably 69 mol% or more, more preferably more than 70 mol%, further preferably 71 mol% or more, particularly preferably 72 mol% or more, 73 mol% or more, 75 mol% or more, 77 mol%. As mentioned above, 78 mol% or more or 80 mol% or more may be preferable. The upper limit of the saponification degree is preferably less than 99.7 mol%, more preferably less than 99.0 mol%. If the degree of saponification is less than 68 mol%, the water solubility of the modified PVA (A) may decrease, making it difficult to prepare a coating agent. In addition, the water resistance of the release paper base paper may decrease. Furthermore, when a coating agent is prepared using modified PVA (A) having a saponification degree of less than 68 mol%, the coating agent has a cloud point, phase separation occurs during coating and drying, and uniform coating is performed. The work surface cannot be formed, and the sealing effect of silicone may be reduced. On the other hand, when the saponification degree is 99.9 mol% or more, production is difficult. The saponification degree is a value obtained by measuring according to JIS K 6726: 1994.

Since the modified PVA (A) has an ethylenic double bond derived from a predetermined esterifying agent (hereinafter, also referred to as "modifying group of the side chain") in the side chain, it has peculiar performance in various applications due to its reactivity. Demonstrate. In particular, it has excellent water solubility, has little water-insoluble content immediately after production and after long-term storage, accelerates the curing of silicone in the release layer when used as a paper coating agent, and improves the adhesion between the base material and the release layer. Can be made to. It is important that the content of the modifying group in the side chain is 0.01 mol% or more and less than 0.50 mol% with respect to all the monomer units. The lower limit of the content is preferably 0.03 mol% or more, more preferably 0.05 mol% or more, further preferably 0.08 mol% or more, and particularly preferably 0.09 mol% or more. The upper limit of the content is preferably 0.45 mol% or less, more preferably 0.43 mol% or less, further preferably 0.40 mol% or less, particularly preferably 0.38 mol% or less, and modified PVA (A). From the viewpoint of reducing the water-insoluble content of the above, 0.35 mol% or less, 0.33 mol% or less, or 0.30 mol% or less may be preferable. When the content of the modifying group in the side chain is less than 0.01 mol%, the effect derived from the modifying group is small, the curing of the silicone is inferior especially when used as a paper coating agent, and the substrate and the release layer Adhesion with and is reduced. On the other hand, when it is 0.50 mol% or more, the water-insoluble content of the modified PVA (A) increases, the silicone is inferior in curing when used as a paper coating agent, and the base material and the release layer adhere to each other. The sex is reduced.

As long as the effects of the present disclosure are exhibited, the modified PVA (A) may contain other modifying groups in its side chain, but the content of the other modifying groups is 5 mol% with respect to the total monomer unit. Less than, preferably less than 1 mol%, more preferably less than 0.1 mol%, and particularly preferably less than 0.01 mol%.

_{It is important that W 0.05h,} which represents the peak width at a height of 5% from the baseline in the peak of modified PVA (A) measured by HPLC, is 2.85 minutes or more and less than 3.70 minutes. .. The _{lower limit of W 0.05h} may be 2.90 minutes or more, 2.95 minutes or more, or 2.99 minutes or more. The _{upper limit of W 0.05h} is preferably less than 3.68 minutes, more preferably less than 3.65 minutes, still more preferably less than 3.63 minutes, and from the viewpoint of reducing the water-insoluble content of the modified PVA (A). Less than 60 minutes, less than 3.58 minutes, less than 3.55 minutes, less than 3.48 minutes, less than 3.45 minutes, less than 3.42 minutes, or less than 3.40 minutes may be preferred. The peak width W _0.05h indicates uneven modification of the modifying group of the side chain in the modified PVA (A), and the wider the width, the larger the uneven modification. In addition, in this specification, the modification unevenness means the bias of the amount of modification groups of the side chain introduced into each modified PVA (A) chain, and the modification group of the side chain is transferred to each modified PVA (A) chain. When introduced uniformly, the denaturation unevenness is small. In other words, the _{narrow peak width W 0.05h} indicates that the modification unevenness is small when the content of the modifying group in the side chain is the same in each modified PVA (A) chain. When the peak width W _0.05h is within the above range, the water-insoluble content of the modified PVA (A) immediately after production and after long-term storage is small, and the curing of the silicone in the release layer is promoted when used as a paper coating agent. It is possible to improve the adhesion between the base material and the release layer. When W _0.05h is less than 2.85 minutes, it means that the modification unevenness of the modifying group of the side chain is very small.

For example, as described later, a specific unsaturated carboxylic acid as an esterifying agent for a vinyl alcohol-based polymer (B) (hereinafter, may be abbreviated as "PVA (B)") using the modified PVA (A) as a raw material. When an acid and / or a derivative thereof (for example, an itaconic acid and / or a derivative thereof, a methacrylic acid and / or a derivative thereof) is esterified, PVA (B) is added to a solution at the time of production in order to minimize modification unevenness. The reaction in the form, that is, the reaction in a uniform system is indispensable, and PVA (B) is dissolved in a soluble solvent such as DMSO and esterified. In such a homogeneous system, modified PVA (A) can be obtained in which the modification unevenness of the modifying group of the side chain is very small, that is, W _{0.05h is less than 2.85 minutes.} However, in this case, since the solvent has a high boiling point in the subsequent step of removing and recovering the solvent, there is a problem that productivity and economy on an industrial scale are very poor, and production is difficult. Further, if the denaturation unevenness is too small, an aggregate of PVA chains is likely to occur due to an increase in the proportion of PVA chains having the same structure and denaturation rate, and as a result, water insolubilization in the modified PVA (A) is likely to occur. Minutes increase. When W _0.05h is 3.70 minutes or more, it means that there is a lot of uneven modification, which means that esterification is proceeding locally, so that the water-insoluble content of the modified PVA (A) increases. When used as a paper coating agent, the curing of silicone is inferior, and the adhesion between the base material and the release layer is lowered.

W _0.05h is defined by the value used in the calculation of the symmetry coefficient in JIS K 0124: 2011. W _0.05h represents the peak width at a height of 1/20 of the peak height from the baseline of the measured peak in HPLC.

The specific measurement conditions for _{W 0.05h} of the modified PVA (A) in the present disclosure are as follows.
Sample concentration: 5 mg / mL
Sample solvent: Water injection amount: 30 μL
Detector: Evaporative light scattering detector ELSD-LTII (manufactured by Shimadzu Corporation)
Column temperature: 45 ° C
Mobile phase: A; ion-exchanged water, B; ethanol (99.5%)
Mobile phase flow rate: 0.4 mL / min Column: Simpack G-ODS (4), inner diameter 4 mm x length 1 cm, particle size 5 μm, gradient condition manufactured by Shimadzu Corporation: ion-exchanged water as mobile phase A, and mobile phase B Before injecting the sample solution, the inside of the column of the HPLC system is in a state where mobile phase A / mobile phase B is filled with a mixed solvent having a volume ratio of 95/5. In this state, the sample solution is injected. Then, the mobile phase A / mobile phase B flows a liquid of 95/5 in volume ratio for 5 minutes immediately after the injection of the sample solution, and then the ratio of the mobile phase B in the mobile phase is increased at a constant rate over 20 minutes. The proportion of mobile phase B is set to 100% 25 minutes after the injection of the sample solution.

In certain embodiments, the modified PVA (A) in the present disclosure includes modified PVA (A) having an ethylene unit in the main chain. A coating agent containing modified PVA (A) having an ethylene unit in the main chain is preferable in that it has more excellent barrier properties and excellent sealing properties. The modified PVA (A) having an ethylene unit in the main chain can be obtained by using PVA (ethylene-vinyl alcohol copolymer) having an ethylene unit in the main chain as PVA (B). PVA (B) having an ethylene unit can be obtained by copolymerizing a vinyl ester-based monomer and ethylene to obtain an ethylene-vinyl ester copolymer, and then saponifying the ethylene-vinyl ester copolymer. be able to. In the modified PVA (A) having an ethylene unit in the main chain, the lower limit of the content of ethylene units is preferably 1 mol% or more, more preferably 2 mol% or more, based on all the monomer units of the modified PVA (A). , 2.5 mol% or more is more preferable. The upper limit of the content of ethylene units is preferably 10 mol% or less, more preferably 8 mol% or less, still more preferably 7 mol% or less, based on all the monomer units of the modified PVA (A). When the content of ethylene units is 10 mol% or less, insoluble matter is unlikely to be generated when the modified PVA (A) is dissolved in water.

(Sodium acetate)
It is important that the content of sodium acetate in the coating agent of the present disclosure is 0.01 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the modified PVA (A). If the sodium acetate content is less than 0.01 parts by mass with respect to 100 parts by mass of the modified PVA (A), the pH of the coating agent (coating liquid) becomes too low, causing acid corrosion of the coating machine. It becomes. The content of sodium acetate is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and further preferably 0.5 parts by mass or more. On the other hand, when the content of sodium acetate exceeds 10 parts by mass with respect to 100 parts by mass of the modified PVA (A), the adhesion between the base material and the release layer cannot be improved. The content of sodium acetate is preferably 8 parts by mass or less, more preferably 7 parts by mass or less, and further preferably 6 parts by mass or less.

The method of adding sodium acetate is not particularly limited, and for example, (i) a method of reacting the esterifying agent with PVA (B) in the presence of sodium acetate, (ii) modified PVA (A) and sodium acetate Examples include a method of dissolving the sodium acetate in water. Above all, the method (ii) above is preferable.

The coating agent of the present disclosure has a conjugated double bond and has two or more hydroxyl groups bonded to the conjugated double bond, or a salt thereof or an oxide thereof (e1), as long as the effects of the present disclosure are not impaired. ) (Hereinafter abbreviated as "compound (e1)"), the compound (E) which is one or more selected from the group consisting of the alkoxyphenol (e2) and the cyclic nitroxyl radical (e3) may be contained.

In compound (e1), the hydroxyl group bonded to the conjugated double bond means the hydroxyl group bonded to the carbon atom constituting the conjugated carbon-carbon double bond. Examples of the compound (e1) include conjugated polyenes having a structure in which carbon-carbon double bonds and carbon-carbon single bonds are alternately linked. As a conjugated polyene, a conjugated diene having a structure in which two carbon-carbon double bonds and one carbon-carbon single bond are alternately connected, three carbon-carbon double bonds and two carbons- Examples thereof include a conjugated triene having a structure in which carbon single bonds are alternately connected.

The conjugated polyene also includes a conjugated polyene in which a plurality of sets of conjugated double bonds composed of a plurality of carbon-carbon double bonds are not conjugated to each other and are contained in one molecule. Further, the conjugated polyene may be linear or cyclic.

Further, the compound (e1) includes not only the above-mentioned conjugated polyene but also aromatic hydrocarbons such as benzene and α, β-unsaturated carbonyl compounds having a carbon-carbon double bond conjugated with a carbonyl group in the molecule. Is also included.

In compound (e1), the hydroxyl group may be bonded to a carbon atom constituting a conjugated carbon-carbon double bond, the bond position is not particularly limited, and the total number of hydroxyl groups may be two or more. .. When the compound having a conjugated double bond is a conjugated polyene, a compound in which a hydroxyl group is bonded to an unsaturated carbon can be mentioned. When the compound having a conjugated double bond is an aromatic hydrocarbon, a compound in which a hydroxyl group is bonded to a carbon atom constituting an aromatic ring can be mentioned. When the compound having a conjugated double bond is an α, β-unsaturated carbonyl compound, a compound in which a hydroxyl group is bonded to the α-position and the β-position can be mentioned.

The compound (e1) is preferably a compound in which two or more hydroxyl groups are bonded to carbon atoms constituting the aromatic ring, or a salt thereof or an oxide thereof, and the α-position and β of the α, β-unsaturated carbonyl compound. It is also preferable that the compound has two or more hydroxyl groups bonded to the position, or a salt thereof or an oxide thereof. Of these, a compound in which two or more hydroxyl groups are bonded to a carbon atom constituting an aromatic ring, a salt thereof, or an oxide thereof is more preferable.

Examples of the compound in which two or more hydroxyl groups are bonded to the carbon atom constituting the aromatic ring include polyphenol. Examples of the polyphenol include hydroxybenzene such as pyrogallol, fluoroglucinol, hydroxyquinol, and hexahydroxybenzene; phenolcarboxylic acid such as gallic acid; phenolcarboxylic acid ester such as gallic acid alkyl ester; epicatechin, epigalocatechin, and epigallo. Examples include catechins such as catechin-3-gallate. Examples of the gallate alkyl ester include methyl gallate, ethyl gallate, propyl gallate, octyl gallate, and dodecyl gallate.

Among these, the compound (e1) is preferably a phenol carboxylic acid or a phenol carboxylic acid ester, more preferably a gallic acid or an alkyl gallic acid ester, and even more preferably an alkyl gallic acid ester.

Further, ascorbic acid and the like can be mentioned as a compound in which two or more hydroxyl groups are bonded to the α-position and the β-position of the α, β-unsaturated carbonyl compound. The compound (e1) is also preferably ascorbic acid.

The compound (e1) used in the present disclosure may be a salt of the above-mentioned compound. The salt of the above-mentioned compound refers to a metal alkoxide in which the hydrogen atom of the hydroxyl group bonded to the conjugated double bond is replaced with a metal, or a carboxylate in which the hydrogen of the carboxy group in the molecule is replaced with a metal. Examples of the metal include sodium and potassium. Examples of the salt of the compound having two or more hydroxyl groups bonded to the conjugated double bond include gallic acid salts such as sodium gallate; and ascorbate salts such as sodium ascorbate.

The compound (e1) used in the present disclosure may be an oxide of the above-mentioned compound. The oxide of the above-mentioned compound means a compound in which a hydroxyl group bonded to a conjugated double bond is oxidized. Examples of such compounds include benzoquinone, dehydroascorbic acid and the like.

By using the alkoxyphenol (e2), a coating agent composition having a better hue can be obtained. Here, the alkoxyphenol (e2) in the present disclosure refers to a compound in which at least one hydrogen atom of the benzene ring is substituted with an alkoxy group and at least one hydroxyl group is substituted. Other hydrogen atoms may be substituted with an alkyl group such as a methyl group or an ethyl group or a halogen group, and the number and bond position thereof are not limited. The number of carbon atoms of the alkoxy group is usually 10 or less, preferably 8 or less, more preferably 6 or less, further preferably 4 or less, and particularly preferably 2 or less. The carbon chain of the alkoxy group may be linear or branched, but is preferably linear from the viewpoint of solubility in water. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group and the like, and a methoxy group is preferable.

The alkoxyphenol (e2) used in the present disclosure is preferably a compound in which one hydrogen atom of the benzene ring is substituted with an alkoxy group and one is substituted with a hydroxyl group. At this time, the bonding position of the alkoxy group is not particularly limited, but in the obtained coating agent composition, the ortho-position or the para-position is preferable and the para-position is preferable from the viewpoint that the insoluble content in water can be further reduced. Is more preferable.

Examples of the alkoxyphenol (e2) preferably used in the present disclosure include methoxyphenol, ethoxyphenol, propoxyphenol, butoxyphenol and the like. Among them, methoxyphenol and ethoxyphenol are preferable, and methoxyphenol is more preferable.

The cyclic nitroxyl radical (e3) in the present disclosure has a heterocycle formed from a carbon atom and a hetero atom, and the nitrogen atom of the nitroxyl radical (= NO ·) forms a part of the ring. It refers to a compound that produces radicals. Examples of the hetero atom constituting the ring include an oxygen atom, a phosphorus atom, a sulfur atom and the like in addition to the nitrogen atom. The number of atoms forming a ring is usually 5 or 6. Substituents such as an alkyl group, a hydroxyl group, a carboxy group, a sulfo group, and a halogen group may be bonded to the atom forming the ring. The number of substituents and the bonding position of the substituents are not particularly limited, and a plurality of substituents may be bonded to the same or different atoms. In the obtained coating agent composition, the cyclic nitroxyl radical (e3) is 2,2,6,6-tetramethylpiperidine1-oxyl (TEMPO) from the viewpoint that the insoluble matter in water can be further reduced. Or a derivative thereof. As the derivative of TEMPO, 4-hydroxy-2,2,6,6-tetramethylpiperidine1-oxyl is preferably used.

The content of the compound (E) is 0.001 with respect to 100 parts by mass of the modified PVA (A) because the hue of the coating agent composition is good and the insoluble content in water can be further reduced. It is preferably more than parts by mass and less than 5 parts by mass. The content of the compound (E) is preferably 0.005 part by mass or more with respect to 100 parts by mass of the modified PVA (A), and is 0, from the viewpoint that the insoluble content in water can be further reduced. It is more preferably 0.01 parts by mass or more, further preferably 0.05 parts by mass or more, and particularly preferably 0.1 parts by mass or more. Regarding the content of the compound (E), even if the release paper is stored for a long period of time, the compound (E) suppresses the occurrence of bleed-out at the interface between the PVA layer and the silicone layer, and the base material and the release layer are separated from each other. From the viewpoint of excellent adhesion, it is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and further preferably 2 parts by mass or less with respect to 100 parts by mass of the modified PVA (A). It is particularly preferable that the amount is 1 part by mass or less.

[Manufacturing method of modified PVA (A)]
The modified PVA (A) of the present disclosure is, for example, a heat treatment modification step of heat-treating and modifying a commercially available PVA (B) having the predetermined saponification degree and viscosity average polymerization degree in the presence of a solvent and an esterifying agent. The method for producing, wherein the solvent is one or more selected from the group consisting of acetone, methanol and methyl acetate, and the esterifying agent is a carboxylic acid having a carbon-carbon double bond and / or a derivative thereof. Can be manufactured by. The PVA (B) used as a raw material is, for example, a polymerization step of polymerizing a vinyl ester-based monomer to obtain a vinyl ester-based polymer, and a saponification step of saponifying the obtained vinyl ester-based polymer to obtain PVA. It can be manufactured by a manufacturing method including.

Examples of the polymerization method include known methods such as a massive polymerization method, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, and a dispersion polymerization method. From an industrial point of view, a solution polymerization method, an emulsion polymerization method, and a dispersion polymerization method are used. Is preferable. In the polymerization operation, any of the batch method, the semi-batch method and the continuous method can be adopted.

Examples of the vinyl ester-based monomer include vinyl acetate, vinyl formate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatic acid, vinyl cinnate, vinyl crotonic acid, vinyl decanoate, and vinyl hexanoate. , Vinyl octanate, vinyl isononanoate, vinyl trimethylacetate, vinyl 4-tert-butylbenzeneate, vinyl 2-ethylhexanoate, vinyl caproate, vinyl caprylate, vinyl laurate, vinyl palmitate, vinyl stearate, olein Examples thereof include vinyl acetate and vinyl benzoate, and vinyl acetate is particularly preferable from an industrial point of view.

In the polymerization step, a monomer other than the vinyl ester-based monomer may be copolymerized as long as the gist of the present disclosure is not impaired. By copolymerizing another monomer with a vinyl ester-based monomer, it is possible to have a structure of another monomer unit in the main chain of the obtained polymer. Examples of the other monomer include α-olefins such as ethylene and propylene; (meth) acrylate and salts thereof; methyl (meth) acrylate, ethyl (meth) acrylate, n (meth) acrylate. -Propyl, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth) (Meta) acrylic acid esters such as dodecyl acrylate and octadecyl (meth) acrylate; (meth) acrylamide; N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N-dimethyl (meth) (Meta) such as acrylamide, diacetone (meth) acrylamide, (meth) acrylamide propanesulfonic acid and its salt, (meth) acrylamide propyldimethylamine and its salt or its quaternary salt, N-methylol (meth) acrylamide and its derivatives, etc. Acrylamide derivatives; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether; acrylonitrile, methacrylonitrile, etc. Butyls; vinyl halides such as vinyl chloride and vinyl fluoride; vinylidene halides such as vinylidene chloride and vinylidene fluoride; allyl compounds such as allyl acetate and allyl chloride; Examples thereof include aliphatic unsaturated dicarboxylic acids and salts thereof or esters thereof; diene-based monomers such as butadiene, isoprene and chloroprene; vinylsilyl compounds such as vinyltrimethoxysilane; isopropenyl acetate and the like. When copolymerizing such other monomers, the content thereof is usually 5 mol% or less. In this specification, methacryl and acrylic are collectively referred to as "(meth) acrylic".

As the solvent used in the polymerization step, an alcohol solvent is preferable. Examples of the alcohol solvent include methanol, ethanol, propanol and the like, and methanol is preferable. These may be used alone or in combination of two or more.

The polymerization initiator used in the polymerization step is not particularly limited, and can be selected from known polymerization initiators depending on the polymerization method. Examples of the polymerization initiator include an azo-based polymerization initiator, a peroxide-based polymerization initiator, a redox-based polymerization initiator, and the like.

Examples of the azo-based polymerization initiator include 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (isobutyronitrile), and 2,2'-azobis (4-methoxy-). 2,4-Dimethylvaleronitrile) and the like.

Peroxide peroxide-based polymerization initiators are peroxydicarbonate compounds such as diisopropylperoxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, and diethoxyethylperoxydicarbonate; t-butylperoxyneodecanoate, cumil. Peroxyester compounds such as peroxyneodecanoate; acetyl (cyclohexylsulfonyl) peroxide; 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate and the like.

As the redox-based polymerization initiator, a combination of an oxidizing agent and a reducing agent can be used. Peroxide is preferable as the oxidizing agent. Examples of the reducing agent include metal ions and reducing compounds. Examples of the combination of the oxidizing agent and the reducing agent include a combination of a peroxide and a metal ion; a combination of a peroxide and a reducing compound; a combination of a peroxide and a metal ion and a reducing compound, and the like. Examples of the peroxide include hydrogen peroxide, cumene hydroperoxide, hydroperoxide such as t-butyl hydroperoxide, persulfate (potassium, sodium or ammonium salt), t-butyl peracetic acid, and peracid ester (perbenzoic acid t). -Butyl) and the like. Examples of the metal ion include metal ions capable of receiving one electron transfer such ^{as Fe 2+} , Cr ²⁺ , V ²⁺ , Co ²⁺ , Ti ³⁺ , and Cu ^+. Examples of the reducing compound include sodium hydrogen sulfite, sodium hydrogen carbonate, tartaric acid, fructose, dextrose, sorbose, inositol, longalite and ascorbic acid. Among these, one or more peroxides selected from the group consisting of hydrogen peroxide, potassium persulfate, sodium persulfate and ammonium persulfite, and sodium hydrogen sulfite, sodium hydrogen carbonate, tartaric acid, longalite and ascorbic acid. A combination with one or more reducing agents selected from the group is preferable, and hydrogen peroxide and one or more reducing agents selected from the group consisting of sodium bisulfite, sodium hydrogen carbonate, tartrate acid, longalite and ascorbic acid. The combination of is more preferable. Further, a water-soluble polymerization initiator such as potassium persulfate, ammonium persulfate, hydrogen peroxide, and cumene hydroperoxide may be combined with the above-mentioned polymerization initiator to obtain a polymerization initiator. These polymerization initiators may be used alone or in combination of two or more.

In the polymerization step, a degree of polymerization adjusting agent (chain transfer agent) may be used if necessary. Aldehydes are preferable as the degree of polymerization adjusting agent. Examples of aldehydes include acetaldehyde, propyl aldehyde, butyraldehyde, isobutyraldehyde, pentyl aldehyde, hexyl aldehyde, heptyl aldehyde, octyl aldehyde and the like. Among them, an aldehyde having 2 to 4 carbon atoms is preferable, and acetaldehyde, propylaldehyde or aldehyde is preferable from the viewpoint of the water solubility of the obtained modified PVA (A) and the storage stability when the modified PVA (A) is used as a paper coating agent. Butyraldehyde is more preferable, and acetaldehyde is further preferable from the viewpoint of availability. The amount of the degree of polymerization adjusting agent used is preferably 0.5% by mass or more and 10% by mass or less, more preferably 1% by mass or more and 5% by mass or less, based on the vinyl ester-based monomer. In one preferred embodiment, a polymerization step of polymerizing a vinyl ester-based monomer without using a degree of polymerization adjusting agent (for example, a modifier that introduces a propyl group at the terminal of propanethiol, propylaldehyde, etc.) is obtained. Examples thereof include a saponification step of saponifying the vinyl ester-based polymer to obtain PVA (B), and a method for producing modified PVA (A) including the heat treatment modification step.

The polymerization rate of the vinyl ester-based monomer in the polymerization step is not particularly limited, but is preferably 20% or more and less than 90%, more preferably 25% or more and less than 80%, and further preferably 30% or more and less than 60%. When the polymerization rate is 20% or more, the productivity is high, and when it is less than 90%, the performance when the modified PVA (A) is used as a paper coating agent tends to be good.

The method for saponifying the vinyl ester-based polymer obtained in the polymerization step is not particularly limited, and a known saponification method can be adopted. For example, an alcohol decomposition reaction or a hydrolysis reaction using a basic catalyst such as sodium hydroxide, potassium hydroxide or sodium methoxide or an acidic catalyst such as p-toluenesulfonic acid can be mentioned. Examples of the solvent that can be used in this reaction include alcohols such as methanol and ethanol; esters such as methyl acetate and ethyl acetate; ketones such as acetone and methyl ethyl ketone: aromatic hydrocarbons such as benzene and toluene. One of these solvents may be used alone, or two or more of these solvents may be used in combination. Above all, a method of saponifying using methanol or a mixed solution of methanol / methyl acetate as a solvent and sodium hydroxide as a catalyst is convenient and preferable.

By undergoing a heat treatment modification step of heat-treating and denaturing PVA (B) obtained by the saponification step in the presence of a specific solvent and a specific esterifying agent, a double bond derived from the esterifying agent is introduced into the side chain. In addition, modified PVA (A) can be obtained in _{which the peak width W 0.05h} at a height of 5% from the baseline at the peak measured by HPLC is a value within a specific range.

The esterifying agent used in the present disclosure is a carboxylic acid having a carbon-carbon double bond and / or a derivative thereof. Examples of the carboxylic acid having a carbon-carbon double bond and / or a derivative thereof include unsaturated monocarboxylic acids, unsaturated dicarboxylic acids, unsaturated tricarboxylic acids, and / or derivatives thereof. One type of esterifying agent may be used alone, or two or more types may be used in combination. These carboxylic acids and / or derivatives thereof can also be used as salts. Examples of the derivative include unsaturated monocarboxylic acid anhydride, unsaturated dicarboxylic acid anhydride, unsaturated monocarboxylic acid ester, unsaturated dicarboxylic acid monoester, and unsaturated dicarboxylic acid diester.

Examples of the unsaturated monocarboxylic acid include (meth) acrylic acid, crotonic acid, isocrotonic acid, 2-pentenoic acid, 4-pentenoic acid, 2-heptenoic acid, 2-octenoic acid, myristolenic acid, and palmitoleic acid. An aliphatic unsaturated monocarboxylic acid having one carbon-carbon double bond such as oleic acid, elaidic acid, buxenic acid, gadrainic acid, erucic acid, nervonic acid; sorbic acid, linoleic acid, linolenic acid, eleostearic acid. , Stearidonic acid, arachidonic acid, eikosapentaenoic acid, 4,8,12,15,19-docosapentaenoic acid (iwashi acid), docosahexaenoic acid, etc. Carous acid; Examples thereof include unsaturated monocarboxylic acids having one or more carbon-carbon double bonds such as aromatic unsaturated monocarboxylic acids such as silicic acid. Examples of the unsaturated dicarboxylic acid include aliphatic unsaturated dicarboxylic acids having one carbon-carbon double bond such as maleic acid, fumaric acid, itaconic acid, citraconic acid, and mesaconic acid. Examples of the unsaturated tricarboxylic acid include aconitic acid and the like. Examples of the unsaturated monocarboxylic acid anhydride include anhydrous (meth) acrylic acid. Examples of the unsaturated dicarboxylic acid anhydride include maleic anhydride, itaconic anhydride, citraconic anhydride and the like. Examples of the unsaturated monocarboxylic acid ester include (meth) acrylic acid alkyl esters such as methyl (meth) acrylate and ethyl (meth) acrylate, and crotonic acid alkyl esters. Examples of the unsaturated dicarboxylic acid monoester include maleic acid monoalkyl esters such as monomethyl maleate, fumaric acid monoalkyl esters, itaconic acid monoalkyl esters, citraconic acid monoalkyl esters, and mesaconic acid monoalkyl esters. .. Examples of the unsaturated dicarboxylic acid diester include itaconic acid dialkyl esters such as maleic acid dialkyl ester, fumaric acid dialkyl ester, itaconic acid dimethyl, and itaconic acid diethyl.

Among the esterifying agents, from aliphatic unsaturated monocarboxylic acids and / or derivatives thereof (acid anhydrides, esters) and aliphatic unsaturated dicarboxylic acids and / or derivatives thereof (acid anhydrides, monoesters, diesters). One or more selected from the above group is preferable, and one aliphatic unsaturated monocarboxylic acid having one carbon-carbon double bond and / or a derivative thereof (acid anhydride, ester), and one carbon-carbon double bond. More preferably, one or more selected from the group consisting of an aliphatic unsaturated dicarboxylic acid having one and / or a derivative thereof (acid anhydride, monoester, diester) has 3 to 3 carbon atoms having one carbon-carbon double bond. Selected from the group consisting of 10 aliphatic unsaturated monocarboxylic acids and / or derivatives thereof, and aliphatic unsaturated dicarboxylic acids having 4 to 10 carbon atoms having one carbon-carbon double bond and / or derivatives thereof 1 More than a species, more preferably, an aliphatic unsaturated monocarboxylic acid having 3 to 6 carbon atoms having one carbon-carbon double bond and / or a derivative thereof, and 4 to 4 carbon atoms having one carbon-carbon double bond. One or more selected from the group consisting of the aliphatic unsaturated dicarboxylic acid and / or a derivative thereof of 6 is particularly preferable, and selected from the group consisting of an esteric acid and / or a derivative thereof, and (meth) acrylic acid and / or a derivative thereof. One or more of them are most preferable. It is also a preferred embodiment that the esterifying agent is an aliphatic unsaturated carboxylic acid and / or a derivative thereof (acid anhydride, ester) in which the carbon at the α-position has a carbon-carbon double bond.

（式中、Ｒ¹、Ｒ²及びＲ³はそれぞれ独立して、水素原子、置換基を有していてもよい炭素数１〜１０のアルキル基、又はカルボキシ基を表し、Ｘは置換基を有していてもよい炭素数１〜１０のアルキレン基、又は炭素−炭素間の単結合を表す。） It is also preferable that the esterifying agent is an aliphatic unsaturated carboxylic acid represented by the following general formula [I] and / or a derivative thereof (acid anhydride, ester).

(In the formula, R ¹ , R ² and R ³ each independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms which may have a substituent, or a carboxy group, and X represents a substituent. It represents an alkylene group having 1 to 10 carbon atoms which may be possessed, or a carbon-carbon single bond.)

The alkyl groups of R ¹ , R ² and R ³ may be linear or branched. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, an isopentyl group and the like. The number of carbon atoms of the alkyl group is preferably 1 to 8, more preferably 1 to 6, further preferably 1 to 4, particularly preferably 1 to 3, and may be 1 to 2. The alkylene group of X may be linear or branched. Examples of the alkylene group include a methylene group, an ethylene group, an n-propylene group, an isopropylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group and a decylene group. The alkylene group preferably has 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms, further preferably 1 to 4 carbon atoms, particularly preferably 1 to 3 carbon atoms, and may be 1 to 2 carbon atoms. Examples of the substituent include an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), a hydroxyl group, a mercapto group and the like. The alkyl groups of R ¹ , R ² and R ^{3 may be unsubstituted.} The alkylene group of X may be unsubstituted. The derivative of the aliphatic unsaturated carboxylic acid represented by the general formula [I] is a carboxylic acid anhydride formed by dehydration condensation of two molecules of the aliphatic unsaturated carboxylic acid represented by the general formula [I]. You may.

The amount of the esterifying agent used is preferably 0.2 parts by mass or more and 10 parts by mass or less, and more preferably 0.5 parts by mass or more and 6 parts by mass or less with respect to 100 parts by mass of PVA (B).

The temperature for heat treatment is usually 50 ° C. to 200 ° C., preferably 70 to 180 ° C., and more preferably 80 to 160 ° C. from the viewpoint of accelerating the reaction between PVA (B) and the esterifying agent. The reaction time is usually 10 minutes to 24 hours.

Further, it is preferable that PVA (B) is in the form of powder because it is easy to adjust the value of _{W 0.05h within the above range.} It is preferable to carry out the heat treatment modification step in the presence of a specific solvent because _{the value of W 0.05h} can be easily adjusted to the above range. Solvents include acetone, methanol, and methyl acetate. These may be used alone or in combination of two or more. As a solvent, the water-insoluble content is smaller immediately after production and after long-term storage, and when modified PVA (A) is used as a paper coating agent, curing of the silicone in the release layer is promoted, and the base material and the release layer are separated from each other. One or more selected from the group consisting of methanol and methyl acetate is preferable from the viewpoint of improving adhesion, and methanol and methyl acetate have a significantly low water-insoluble content immediately after production and after long-term storage. A mixed solvent is more preferable. Moderate plasticization of PVA (B) with methanol and methyl acetate particularly contributes to the adjustment of the _{W 0.05h value.}

The amount of the solvent used in the heat treatment modification step is not particularly limited, but is preferably 1 part by mass or more and less than 100 parts by mass, and more preferably 3 parts by mass or more and less than 70 parts by mass with respect to 100 parts by mass of PVA (B). It is more preferably 5 parts by mass or more and less than 50 parts by mass, and particularly preferably 5 parts by mass or more and less than 30 parts by mass. When the amount of the solvent used is 1 part by mass or more with respect to 100 parts by mass of PVA (B), the occurrence of denaturation unevenness due to the occurrence of a local reaction is suppressed, and _{the value of W 0.05h} becomes moderately small. , Water insoluble content is likely to be reduced. On the other hand, if the amount of the solvent used is less than 100 parts by mass with respect to 100 parts by mass of PVA (B), PVA (B) are fused to each other during heat treatment and heat transfer becomes non-uniform, resulting in uneven modification. It is _{easy for} the value of W 0.05h to be moderately small and the water-insoluble content to be reduced.

Further, in the heat treatment modification step, a specific esterifying agent is present in the presence of one or more compounds (E) selected from the group consisting of the compound (e1), the alkoxyphenol (e2) and the cyclic nitroxyl radical (e3). And PVA (B) can be reacted to obtain modified PVA (A).

The modified PVA (A) was used as an aqueous solution because the side chain had an ethylenic double bond derived from a specific esterifying agent, but the uneven modification represented by _{W 0.05h was in a specific range.} If the water insoluble content is small. Specifically, the water-insoluble content (ppm) of the modified PVA (A) in the aqueous solution prepared after producing the modified PVA (A) and leaving it in the air at 60 ° C. for 1 hour is preferably 3000 ppm or less, preferably 2000 ppm. The following is more preferable, 1900 ppm or less is further preferable, 1500 ppm or less is further preferable, 1000 ppm or less is particularly preferable, and 500 ppm or less is most preferable. The smaller the water-insoluble content (ppm) of the modified PVA (A), the better, but it may be 0 ppm or more, or may exceed 0 ppm. The method for measuring the water-insoluble matter is as described in Examples described later.

(Other ingredients)
The coating agent used in the present disclosure may contain components other than modified PVA (A) and sodium acetate as long as the effects of the present disclosure are not impaired. Other ingredients include, for example, aqueous dispersible resins such as SBR latex, NBR latex, vinyl acetate emulsion, ethylene / vinyl acetate copolymer emulsion, (meth) acrylic ester emulsion, vinyl chloride emulsion; wheat, corn. Raw starch obtained from rice, maltose, sweet potato, tapioca, sago palm, etc .; raw starch decomposition products such as oxidized starch and dextrin; starch derivatives such as etherified starch, esterified starch, cationized starch; methyl cellulose, hydroxyethyl cellulose , Cellulose derivatives such as carboxymethyl cellulose (CMC); Monosaccharides such as glucose, fructose, isomerized sugar, xylose; Disaccharides such as maltose, lactose, sucrose, trehalose, palatinose, reduced maltose, reduced palatinose, reduced lactose; Oligosaccharides such as isomalto-oligosaccharides, fructo-oligosaccharides, lactose oligosaccharides, soybean oligosaccharides, xylooligosaccharides, coupling sugars, cyclodextrin compounds; polysaccharides such as purulan, starch, agar, konjak mannan, polydextrose, xanthan gum; albumin, Examples thereof include gelatin, casein, gum arabic, polyamide resin, melamine resin, poly (meth) acrylamide, polyvinylpyrrolidone, poly (meth) sodium acrylate, anion-modified PVA, sodium alginate, and water-soluble polyester.

Further, as the other component, a pigment is also mentioned. Examples of the pigment include inorganic pigments (clay, kaolin, aluminum hydroxide, calcium carbonate, talc, etc.) and organic pigments (plastic pigment, etc.) generally used in the field of coated paper manufacturing.

Further, as the other components, for example, a viscosity regulator, an adhesion improver, a defoaming agent, a plasticizer, a water resistant agent, a preservative, an antioxidant, a penetrant, a surfactant, a filler, a starch and a derivative thereof. , Latex and the like.

The content of these other components in the coating agent is usually 50 parts by mass or less, 5 parts by mass or less, and 0.1 parts by mass with respect to 100 parts by mass of the modified PVA (A). It may be less than or equal to 0 parts by mass.

(Release paper base paper)
The release paper base paper of the present disclosure is obtained by coating a base material with a coating agent containing a specific amount of modified PVA (A) having an esterifying agent-derived double bond in the side chain and sodium acetate. .. The release paper base paper of the present disclosure has a low air permeation rate and is excellent in sealing property of silicone. Further, by using such a release paper base paper, it is possible to accelerate the curing of the addition type silicone in the release layer, and it is also possible to improve the adhesion to the release layer.

In the present disclosure, as a method for determining the sealing effect of the sealing layer, the air permeability measured using a Wangken type air permeability tester (water column type) according to JIS P 8117 (2009) is used. Can be done. The air permeability is preferably 2000 sec or more, more preferably 2700 sec or more, further preferably 3000 sec or more, particularly preferably 10000 sec or more, and most preferably 30,000 sec or more. When the air permeability is 2000 sec or more, the sealing effect is excellent. The smaller the value of air permeability (seconds; sec), the higher the air permeability.

(Manufacturing method of release paper base paper)
The release paper base paper of the present disclosure is a release paper base paper obtained by coating a base material with a coating agent containing modified PVA (A) and sodium acetate. The method for producing the release paper base paper is not particularly limited, but the first step of reacting the esterifying agent with PVA (B) to obtain modified PVA (A) and the modified PVA (A) obtained in the first step , A method including a second step of dissolving sodium acetate in water to obtain a coating agent and a third step of applying the coating agent obtained in the second step to a base material is preferable.

The first step is as described in the method for producing modified PVA (A).

In the second step, the modified PVA (A) obtained in the first step and sodium acetate are dissolved in water (solvent) to obtain a coating agent. The solvent for dissolving the modified PVA (A) and sodium acetate may contain a solvent other than water. Examples of other solvents include hydrophilic solvents. Examples of the hydrophilic solvent include alcohols such as methanol, ethanol and isopropanol, ketones such as acetone and methyl ethyl ketone, ethers such as tetrahydrofuran, cellosolves, carbitols and nitriles such as acetonitrile. Further, the coating agent may contain inorganic particles such as clay that are insoluble in water. The content of the solvent other than water in the coating agent is preferably 50% by mass or less, and more preferably 20% by mass or less.

The solid content concentration in the coating agent is preferably 2 to 30% by mass. When the solid content concentration is 2% by mass or more, the coating agent is less likely to penetrate into the paper, and the silicone sealing effect is more excellent. The solid content concentration is more preferably 4% by mass or more. On the other hand, when the solid content concentration is 30% by mass or less, leveling is likely to occur when the coating agent is applied to the paper, and the state of the coated surface is likely to be good. The solid content concentration is more preferably 25% by mass or less.

The pH of the coating agent obtained in the second step is preferably 3.0 or more and 7.0 or less. When the pH of the coating agent is in the above range, the corrosion of the coating machine is further reduced. The pH of the coating agent is more preferably 3.5 or higher, and even more preferably 4.0 or higher. The pH of the coating agent is more preferably 6.8 or less. The pH can be measured using a known measuring device. Examples of the measuring device include "LAQUAtwin" manufactured by HORIBA, Ltd.

In the third step, the coating agent obtained in the second step is applied to the paper as the base material. As the paper, known paper obtained by making chemical pulp such as broadleaf kraft pulp and coniferous kraft pulp and mechanical pulp such as GP (crushed wood pulp), RGP (refiner ground pulp) and TMP (thermomechanical pulp) or the like. Synthetic paper can be used. Further, as the above-mentioned paper, high-quality paper, medium-quality paper, alkaline paper, glassin paper, semi-glassin paper, or paperboard or white paperboard used for corrugated cardboard, building materials, white balls, chip balls, etc. may also be used. it can. The paper may contain organic and inorganic pigments, as well as paper-making auxiliary chemicals such as paper strength enhancers, sizing agents, and yield improvers. Further, the paper may be one that has been subjected to various surface treatments.

The coating liquid can be applied with general coating paper application equipment, for example, coating of blade coater, air knife coater, transfer roll coater, rod metering size press coater, curtain coater, wire bar coater, etc. An on-machine coater or an off-machine coater provided with a working device can coat the coating agent on the substrate in one layer or multiple layers. Further, as a drying method after coating, for example, various heat-drying methods such as hot air heating, gas heater heating, and infrared heater heating can be appropriately adopted. The coating amount is preferably 0.3 to 5.0 g / m ^{2 in terms of solid content.} When the coating amount is 0.3 g / m ² or more, the sealing effect of silicone is more excellent. The coating amount is ^{more preferably 0.5 g / m 2} or more. On the other hand, when the coating amount is 5.0 g / m ² or less, the sealing layer does not form an excessive flat surface on the base material, the surface area becomes large to some extent, and then when the silicone layer is formed, it adheres to the silicone layer. It is easy to obtain sufficient sex. The coating amount is ^{more preferably 3.0 g / m 2} or less.

In order to enhance the sealing effect, the coating liquid can be applied and then dried, and a smoothing treatment can be performed as long as the effect is not impaired. As the smoothing process, a super calendar, a gloss calendar, a multi-nip calendar, a soft calendar, a belt nip calendar and the like are preferably adopted.

(Release paper)
Another preferred embodiment of the present disclosure includes a release paper having the above-mentioned release paper base paper and a release layer formed on the surface of the release paper base paper. In the release paper of the present disclosure, the release layer contains addition type silicone (C) and platinum (D), and the content of platinum (D) is 0 with respect to 100 parts by mass of the addition type silicone (C). It is preferably .001 parts by mass or more and 0.05 parts by mass or less. When the content of platinum (D) is within the above range, a release paper having excellent silicone curability can be obtained. When the amount of platinum (D) is 0.001 part by mass or more, the addition type silicone (C) is likely to be cured, and treatment at a high temperature is not required. The content of platinum (D) is preferably 0.002 parts by mass or more, and more preferably 0.004 parts by mass or more, with respect to 100 parts by mass of the addition type silicone (C). On the other hand, when the content of platinum (D) is 0.05 parts by mass or less, the cost can be suppressed, which is economically advantageous. The amount of platinum (D) is preferably 0.03 parts by mass or less, and more preferably 0.02 parts by mass or less with respect to 100 parts by mass of the additive silicone (C).

(Additional silicone (C))
The addition type silicone (C) used in the present disclosure includes an organopolysiloxane (c1) containing at least two carbon-carbon double bonds reactive with a SiH group in one molecule and at least two carbon-carbon double bonds in one molecule. It is obtained by hydrosilylation reaction of an organohydrogen polysiloxane (c2) containing a SiH group in the presence of a platinum catalyst.

The organopolysiloxane (c1) containing at least two carbon-carbon double bonds reactive with the SiH group in one molecule includes a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, and the like. It is an organopolysiloxane containing at least two carbon-carbon double bonds such as a hexenyl group in one molecule. The organopolysiloxane has, for example, a repeating unit of diorganosiloxane in the main chain and a triorganosiloxane structure at the end, and may have a branched or cyclic structure. Examples of the organogroup bonded to silicon at the terminal or in the repeating unit include a methyl group, an ethyl group, and a phenyl group. Specific examples include methylphenylpolysiloxane having vinyl groups at both ends.

The organohydrogen polysiloxane (c2) containing at least two SiH groups in one molecule is an organopolysiloxane containing two or more SiH groups in the terminal and / or repeating structure. The organopolysiloxane has, for example, a repeating unit of diorganosiloxane in the main chain and a triorganosiloxane structure at the end, and may have a branched or cyclic structure. Examples of the organogroup bonded to silicon at the terminal or in the repeating unit include a methyl group, an ethyl group, an octyl group, a phenyl group and the like, and two or more of these are substituted with hydrogen.

The additive silicone (C) used in the present disclosure is appropriately selected from solvent type, solvent-free type, and emulsion type, but solvent-free additive silicone is preferable from the viewpoint of reducing environmental load and coatability. Will be adopted by. Examples of the solvent-free additive silicone (C) include silicones manufactured by Toray Dow Corning Co., Ltd. such as SP7015, SP7259, SP7025, SP7248S, SP7268S, SP7030, SP7265S, LTC1006L, and LTC1056L; KNS-3051, KNS-320A, KNS- Silicone manufactured by Shinetsu Silicone Co., Ltd. such as 316, KNS-3002, KNS-3300, X-62-1387; Silicone manufactured by Asahi Kasei Wacker Silicone Co., Ltd. such as DEHESIVE920, DEHESIVE921, DEHESIVE924, DEHESIVE927, DEHESIVE929; KF-SL101, KF-SL201 , KF-SL202, KF-SL301, KF-SL302 and other silicones manufactured by Arakawa Chemical Industry Co., Ltd .; and examples thereof include silicones manufactured by Momentive Performance Materials Co., Ltd. such as TPR6600 and SL6625. One type of these silicones may be used alone, or two or more types may be used in combination.

(Platinum (D))
A platinum catalyst is usually used for curing silicone, but the type of platinum catalyst used in the present disclosure is not particularly limited. Those that cure the addition type silicone (C) by a hydrosilylation reaction are preferably used. For example, a platinum catalyst manufactured by Toray Dow Corning Inc. such as SP7077R and SRX212, and a platinum catalyst manufactured by Arakawa Chemical Industry Co., Ltd. such as CATA93B can be mentioned. One of these platinum catalysts may be used alone, or two or more of them may be used in combination. The amount of platinum (D) can be determined by quantifying platinum in the platinum catalyst with an ICP emission spectrophotometer or the like.

(Manufacturing method of release paper)
The method for producing the release paper of the present disclosure is not particularly limited, but a coating agent containing modified PVA (A) and sodium acetate is applied onto the base material to form a sealing layer on the base material, and then the release paper is added. A method of forming a release layer by applying a coating liquid prepared so that the contents of the type silicone (C) and platinum (D) are within the above ranges on the sealing layer is preferably adopted. The amount of the coating liquid forming the release layer is not particularly limited, but the solid content is preferably ^{0.1 to 5 g / m 2.} When the coating amount is 0.1 g / m ² or more, the peelability is excellent. The coating amount is ^{more preferably 0.3 g / m 2} or more in terms of solid content. When the coating amount is 5 g / m ² or less, the adhesion between the release layer containing the add-on silicone (C) and platinum (D) and the sealing layer becomes better. The coating amount is ^{more preferably 3 g / m 2} or less in terms of solid content. Various coating methods are used, but a blade coater, an air knife coater, a bar coater and the like are preferable.

The release layer in the release paper of the present disclosure may contain components other than the additive silicone (C) and platinum (D) as long as the effects of the present disclosure are not impaired. The content of other components is usually 30 parts by mass or less, 10 parts by mass or less, or 5 parts by mass or less with respect to 100 parts by mass of the total amount of the peeled layer. Other components include, for example, viscosity modifiers; adhesion improvers; defoamers; plasticizers; water resistant agents; preservatives; antioxidants; penetrants; surfactants; coloring of inorganic pigments, organic pigments, etc. Agents; fillers; starches and derivatives thereof, sugars such as cellulose and derivatives thereof; latex and the like.

The present disclosure includes embodiments in which the above configurations are variously combined within the scope of the technical idea of the present disclosure, as long as the effects of the present disclosure are exhibited.

Hereinafter, the present disclosure will be described in more detail with reference to Examples. In the following Examples and Comparative Examples, unless otherwise specified, "parts" and "%" indicate parts by mass and% by mass, respectively, and ppm indicates mass ppm.

[Viscosity average degree of polymerization of PVA]
The viscosity average degree of polymerization of PVA was measured according to JIS K 6726: 1994. Specifically, when the degree of saponification is less than 99.5 mol%, the PVA saponified to a degree of saponification of 99.5 mol% or more is subjected to the ultimate viscosity [η] (L / L /) measured at 30 ° C. in water. The viscosity average degree of polymerization (P) was determined by the following formula using g). The viscosity average degree of polymerization of the modified PVA having a double bond derived from the esterifying agent is a value measured for the modified PVA isolated by reprecipitation purification after the reaction between the PVA and the esterifying agent.
P = ([η] × 10 ⁴ / 8.29) ^{(1 / 0.62)}

[Saponification degree of PVA]
The degree of saponification of PVA was measured according to JIS K 6726: 1994. The saponification degree of the modified PVA having a double bond derived from the esterifying agent is a value measured for the modified PVA isolated by reprecipitation purification after the reaction with the esterifying agent.

[Content of modifying group in side chain of modified PVA (A)]
The content of the modifying group in the side chain of the modified PVA (A) was measured and calculated by the following method. First, a 10% by mass aqueous solution of modified PVA (A) was prepared. Next, 5 g of this aqueous solution was added dropwise to a solution of 500 g of methyl acetate / water = 95/5 to precipitate the modified PVA (A), which was recovered and dried to release the isolated modified PVA (A) to DMSO-. When _{dissolved in d 6} ^{and measured using 1} H-NMR at 400 MHz, the peak derived from methine in vinyl alcohol units was 3.2 to 4.0 ppm (integrated value [P]), derived from the denaturing group of the side chain. The peaks of the protons of the above are assigned in several places around 5.0 to 6.5 ppm, and any of them can be used (integrated value [Q]), and from each peak, the side chain denaturing group is derived from each peak by the following formula. The content rate was determined.
Content of modified groups in the side chain (mol%) = [Q] / [P] x 100

[Water-insoluble component (a) in aqueous solution of modified PVA (A)]
After producing the modified PVA (A), it was left in the air at 60 ° C. for 1 hour, and then 100 g of a 4% by mass aqueous solution of the modified PVA (A) was prepared, and 200 mesh (mesh equivalent of JIS standard sieve, opening). 75 μm; The mesh size of the sieve conforms to the nominal opening W of JIS Z 8801-2006), and the entire amount is filtered (the mass of the wire mesh before filtration is a (g)), and the entire wire mesh is 105 ° C. The wire mesh was dried for 3 hours (the total mass of the wire mesh after absolute drying and the substance remaining on the wire mesh is b (g)). The water-insoluble content (ppm) was determined using the following formula.
Water insoluble matter (ppm) = 1000000 x (ba) / 4

[Water-insoluble component (b) in aqueous solution of modified PVA (A)]
After producing the modified PVA (A), it was left in the air at 60 ° C. for 6 months, and then 100 g of a 4% by mass aqueous solution of the modified PVA (A) was prepared. Opening 75 μm; The mesh opening of the sieve conforms to the nominal opening W of JIS Z 8801-1-2006), and the entire amount is filtered with a wire mesh (the mass of the wire mesh before filtration is a (g)). It was dried at ° C. for 3 hours (the total mass of the wire mesh after absolute drying and the substance remaining on the wire mesh is b (g)). The water-insoluble content (ppm) was determined using the following formula.
Water insoluble matter (ppm) = 1000000 x (ba) / 4

_{[W 0.05h} measured by HPLC of modified PVA (A)]
_{The W 0.05h} of the modified PVA (A) in the present disclosure was measured as follows.
Sample solution preparation:
To a pressure resistant test tube (φ18 mm, length 18 cm), 5 mL of water was accurately added to 25 mg of the sample, the lid was closed, and the mixture was stirred with an aluminum block type magnetic stirrer. At this time, when the saponification degree of the modified PVA (A) was less than 80 mol%, the modified PVA (A) was stirred and dissolved at 20 ° C. for 1 hour. When the saponification degree of the modified PVA (A) was 80 mol% or more, it was dissolved by stirring at 90 ° C. for 2 hours.
HPLC measurement conditions:
Sample concentration: 5 mg / mL
Sample solvent: Water injection amount: 30 μL
Detector: Evaporative light scattering detector ELSD-LTII (manufactured by Shimadzu Corporation)
Column temperature: 45 ° C
Mobile phase: A; ion-exchanged water, B; ethanol (99.5%)
Mobile phase flow rate: 0.4 mL / min Column: Simpack G-ODS (4), inner diameter 4 mm x length 1 cm, particle size 5 μm, gradient condition manufactured by Shimadzu Corporation: ion-exchanged water as mobile phase A, and mobile phase B Before injecting the sample solution, the inside of the column of the HPLC system is in a state where mobile phase A / mobile phase B is filled with a mixed solvent having a volume ratio of 95/5. In this state, the sample solution is injected. Then, the mobile phase A / mobile phase B flows a liquid of 95/5 in volume ratio for 5 minutes immediately after the injection of the sample solution, and then the ratio of the mobile phase B in the mobile phase is increased at a constant rate over 20 minutes. Twenty-five minutes after injecting the sample solution, the proportion of mobile phase B was adjusted to 100%.

[Example 1]
Production of PVA (A1) In a 1 L eggplant flask, 100 parts of powder PVA (B) having a viscosity average degree of polymerization of 800 and a saponification degree of 72 mol% contains 5 parts of methanol, 15 parts of methyl acetate, and 4 parts of itaconic acid as an esterifying agent. Was added, shaken well, and then heat-treated at 110 ° C. for 4 hours. As a result, the modified PVA (A) has a viscosity average degree of polymerization of 800, a saponification degree of 72 mol%, a double bond derived from itaconic acid of 0.10 mol%, and a value of _{W 0.05 h of 3.} .20 minutes of PVA (A1) was obtained. The water-insoluble content (a) of PVA (A1) was 200 ppm, and the water-insoluble content (b) was 450 ppm.

A 6% by mass aqueous solution of PVA (A1) is prepared, and a coating agent is added to this aqueous solution by adding sodium acetate so that the content of sodium acetate is 1.3 parts by mass with respect to 100 parts by mass of modified PVA (A). Obtained. This coating agent was applied to glassine paper having an air permeability of 100 seconds using a wire bar so that the amount of application was about 1 g / m ^{2 in} dry mass. After coating, it was dried at 100 ° C. for 5 minutes to obtain coated paper. The obtained coated paper was treated twice at 70 ° C. and 400 kg / cm ² on a super calendar to obtain a release paper base paper.

[PH of coating agent]
The pH of the coating agent used to prepare the release paper base paper was measured. The lower the pH, the stronger the acidic solution of the coating liquid, so corrosion of the coating machine becomes a problem. As the pH, 3.5 or more was regarded as acceptable. The results are shown in Table 2.

[Evaluation of air permeability of release paper base paper]
The air permeability of the release paper base paper was measured using a Wangken air permeability tester according to JIS P 8117 (2009), and was used as an index of the sealing property of silicone. As the air permeability, 2000 sec or more was regarded as acceptable. The results are shown in Table 2.

[Evaluation of silicone curability]
A coating made by mixing LTC1056L manufactured by Toray Dow Corning Co., Ltd. as an additive silicone (C) and SRX212 as a platinum catalyst so that the ratio of the additive silicone (C) to platinum (D) is 100 / 0.007. The working liquid was coated on the obtained release paper base paper with a blade coater so that the ^{coating solid content was 1.5 g / m 2.} By doing so, a silicone layer was formed on the release paper base paper. Then, the time until the silicone was cured by heat treatment at 110 ° C. was measured. Here, the time until the silicone is cured means the time (seconds) required until the silicone layer is strongly rubbed with a finger 10 times at predetermined time intervals and the silicone layer is not peeled off at all. The results are shown in Table 2.

[Evaluation of adhesion of peeling layer]
A coating made by mixing LTC1056L manufactured by Toray Dow Corning Co., Ltd. as an add-on silicone (C) and SRX212 as a platinum catalyst so that the ratio of the add-on silicone (C) to platinum (D) is 100 / 0.009. The working liquid is coated on the obtained release paper base paper ^{with a blade coater so that the solid content is 1.5 g / m 2} , heat treated at 110 ° C. for 90 seconds, and a release layer (silicone) is applied on the release paper base paper. A release paper on which a layer) was formed was obtained. The obtained release paper was evaluated by the following indexes. The results are shown in Table 2.
A: After leaving for 1 week under the conditions of 40 ° C. and 90% RH, the silicone layer was rubbed strongly with a finger. As a result, the silicone layer did not peel off. Under the same conditions, after leaving for another week, the silicone layer was rubbed strongly with a finger. As a result, the silicone layer did not peel off.
B: After leaving for 1 week under the conditions of 40 ° C. and 90% RH, the silicone layer was rubbed strongly with a finger. As a result, the silicone layer did not peel off. However, under the same conditions, when the silicone layer was rubbed strongly with a finger after being left for another week, the silicone layer was peeled off.
C: After leaving for 1 week under the conditions of 40 ° C. and 90% RH, the silicone layer was rubbed strongly with a finger. As a result, the silicone layer was peeled off.

[Examples 2 to 9 and Comparative Examples 1 to 3]
Production of PVA (A2) to PVA (A12) Viscosity average degree of polymerization, saponification degree and ethylene unit content of PVA (B) used, type and amount of solvent used, type and amount of esterifying agent, and PVA (A2) to PVA (A12) were produced in the same manner as in Example 1 except that the heat treatment temperature was changed as shown in Table 1. Table 1 shows the content of the modifying group in the side chain, _{the measurement result of W 0.05h} , and the production conditions, and Table 2 shows the measurement result of the water-insoluble matter. Further, a coating agent, a release paper base paper, and a release paper were produced in the same manner as in Example 1 except that the amount of sodium acetate was changed to Table 2. The pH of the coating agent and the performance of the release paper base paper and the release paper were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 4]
Production of PVA (A13) PVA (A13) was produced in the same manner as in Example 1 except that no solvent was used during the heat treatment. Table 1 shows the content of the modifying group in the side chain, _{the measurement result of W 0.05h} , and the production conditions, and Table 2 shows the measurement result of the water-insoluble matter. Further, a coating agent, a release paper base paper, and a release paper were produced in the same manner as in Example 1 except that the amount of sodium acetate was changed to Table 2. The pH of the coating agent and the performance of the release paper base paper and the release paper were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 5]
Production of PVA (A14) 100 parts of PVA (B) having a viscosity average degree of polymerization of 700 and a saponification degree of 70 mol% was added to a solution prepared by dissolving 1 part of itaconic acid in 200 parts of methanol to swell, and then under reduced pressure 40. Drying was carried out at a temperature of ° C. for 24 hours. Then, after heat-treating at 120 ° C. for 4 hours in a nitrogen atmosphere, Soxhlet washing was performed with tetrahydrofuran to obtain PVA (A14). Table 1 shows the content of the modifying group in the side chain, _{the measurement results of W 0.05h} , and the production conditions, and Table 2 shows the measurement results of the water-insoluble matter. Further, a coating agent, a release paper base paper, and a release paper were produced in the same manner as in Example 1 except that the amount of sodium acetate was changed to Table 2. The pH of the coating agent and the performance of the release paper base paper and the release paper were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 6]
Production of PVA (A15) PVA (B) having a viscosity average degree of polymerization of 1700 and a saponification degree of 88 mol% was used as it was as PVA (A15) without esterifying PVA (B) with an esterifying agent. Table 2 shows the measurement results of the water-insoluble matter. Further, a coating agent, a release paper base paper, and a release paper were produced in the same manner as in Example 1 except that the amount of sodium acetate was changed to Table 2. The pH of the coating agent and the performance of the release paper base paper and the release paper were evaluated in the same manner as in Example 1. The results are shown in Table 2. In addition, since the modifying group was not introduced in Comparative Example 6, the measurement by HPLC was performed so that there was no unevenness, and W _0.05h was 2.80.

[Comparative Example 7]
Using PVA (A2) used in Example 1, a coating agent, a release paper base paper, and a release paper were produced in the same manner as in Example 1 except that the amount of sodium acetate was changed to Table 2. The pH of the coating agent and the performance of the release paper base paper and the release paper were evaluated in the same manner as in Example 1. The results are shown in Table 2.

The coating agent of the example had a pH capable of suppressing acid corrosion of the coating machine. On the other hand, the coating agent of Comparative Example 1 could not be coated because the modified PVA contained a large amount of water-insoluble matter. The coating agents of Comparative Examples 2 to 5 already contained a large amount of water-insoluble matter in the modified PVA immediately after production, and some of them had a water-insoluble content several times after long-term storage. Therefore, the coating agent of Comparative Example 7 was coated. The pH of the agent was too low. Further, the coating agent of the example had a low air permeation rate when applied to a release paper base paper, and was excellent in sealing property of silicone. On the other hand, the coating agents of Comparative Examples 2 and 4 to 5 did not have sufficient silicone sealing properties when applied to the release paper base paper. Further, the release paper using the coating agent of the example was excellent in silicone curability and adhesion between the base material and the release layer. On the other hand, the release paper using the coating agents of Comparative Examples 2 to 6 was inferior in the adhesion between the base material and the release layer. The release paper of Comparative Example 6 was also inferior in silicone curability.

From the above results, the coating agent of the present disclosure can suppress acid corrosion of the coating machine, has excellent silicone sealing property when applied to the release paper base paper, promotes curing of the silicone in the release layer, and It was confirmed that the adhesion between the base material and the release layer could be improved.

The coating agents of the present disclosure are particularly useful in the production of release paper base papers and release papers.

Claims (11)

The modified vinyl alcohol-based polymer (A) and sodium acetate are contained, and the modified vinyl alcohol-based polymer (A) has a degree of esterification of 68 mol% or more and less than 99.9 mol%, and a viscosity average degree of polymerization of 200 or more. A carboxylic acid and / or a carboxylic acid that is less than 5000, has 0.01 mol% or more and less than 0.50 mol% of esterifying agent-derived double bonds in the side chain, and the esterifying agent has a carbon-carbon double bond. _{A derivative thereof, the peak width W 0.05h} at a height of 5% from the baseline at the peak measured by high-speed liquid chromatography is 2.85 minutes or more and less than 3.70 minutes.
A coating agent having a sodium acetate content of 0.01 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the modified vinyl alcohol polymer (A). The coating according to claim 1, wherein the esterifying agent is at least one selected from the group consisting of an aliphatic unsaturated monocarboxylic acid and / or a derivative thereof, and an aliphatic unsaturated dicarboxylic acid and / or a derivative thereof. Agent. The esterifying agent is an aliphatic unsaturated monocarboxylic acid having one carbon-carbon double bond and / or a derivative thereof, and an aliphatic unsaturated dicarboxylic acid having one carbon-carbon double bond and / or its derivative. The coating agent according to claim 1, which is one or more selected from the group consisting of derivatives. The coating according to claim 1, wherein the esterifying agent is at least one selected from the group consisting of (i) itaconic acid and / or a derivative thereof, and (ii) (meth) acrylic acid and / or a derivative thereof. Agent. The modified vinyl alcohol-based polymer (A) further has an ethylene unit in the main chain, and the content of the ethylene unit is 1 mol% or more with respect to all the monomer units of the modified vinyl alcohol-based polymer (A). The coating agent according to any one of claims 1 to 4, which is 10 mol% or less. The coating agent according to any one of claims 1 to 5, wherein the degree of saponification of the modified vinyl alcohol polymer (A) is 72 mol% or more and less than 99.0 mol%. In the peak measured by high performance liquid chromatography of the modified vinyl alcohol polymer (A), the peak width W _0.05h at a height of 5% from the baseline is 2.99 minutes or more and less than 3.40 minutes. The coating agent according to any one of claims 1 to 6. A release paper base paper obtained by applying the coating agent according to any one of claims 1 to 7 to a base material. The release paper base paper according to claim 8, wherein the base material is at least one selected from the group consisting of high-quality paper, medium-quality paper, alkaline paper, glassin paper, semi-glassin paper, paperboard, and white paperboard. A release paper having the release paper base paper according to claim 8 or 9 and a release layer formed on the surface of the release paper base paper. The release layer contains addition type silicone (C) and platinum (D), and the content of platinum (D) is 0.001 part by mass or more and 0.05 parts by mass with respect to 100 parts by mass of addition type silicone (C). The release paper according to claim 10, which is not more than parts by mass.