JP2019038935A - Polyvinyl alcohol composition and use therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition containing polyvinyl alcohol, which is excellent in water solubility and storage stability. SOLUTION: A composition (C) containing a modified polyvinyl alcohol (A) and a compound (B); the modified polyvinyl alcohol (A) has a double bond derived from an unsaturated carboxylic acid or a derivative thereof. The chain has 0.01 mol% or more and less than 2 mol%, the degree of saponification of the modified polyvinyl alcohol (A) is 65 mol% or more, and the compound (B) is an alkoxyphenol or a cyclic nitroxyl radical, and has a composition. The composition (C) in which the content of the compound (B) in the substance (C) is 0.001 part by mass or more and less than 5 parts by mass with respect to 100 parts by mass of the modified polyvinyl alcohol (A). [Selection diagram] None

Description

  The present invention relates to a composition (C) containing a modified polyvinyl alcohol (A) and a compound (B). The present invention also relates to a dispersion stabilizer for suspension polymerization of a vinyl compound containing the composition (C). Furthermore, this invention relates to the coating agent which consists of an aqueous solution containing a composition (C).

  Polyvinyl alcohol (hereinafter sometimes abbreviated as “PVA”) has been used in various products such as dispersion stabilizers for suspension polymerization of vinyl compounds, coating agents, adhesives, polarizing films, water-soluble films, pharmaceuticals, and cosmetics. Used for applications. Further, it is known that the presence of a reactive group such as a double bond in PVA can improve various performances or obtain special effects.

  Since the double bond has high reactivity, there is a possibility that the double bond reacts and gels when PVA is stored for a long time. Therefore, various performance may be inferior compared with the case where PVA immediately after manufacture is used. Moreover, since the solubility to water will fall when PVA has a double bond, it may not be applicable to the use for which water solubility is requested | required.

  Examples of applications that require storage stability and water solubility of PVA include dispersion stabilizers for suspension polymerization of vinyl compounds. By using PVA having a double bond as a dispersion stabilizer for suspension polymerization of a vinyl compound, the polymerization reaction of the vinyl compound is stabilized (Patent Documents 1 and 2).

  Patent Document 1 discloses a polyvinyl alcohol polymer (B) having a double bond in a side chain obtained by acetalizing a polyvinyl alcohol polymer (A) with a monoaldehyde having an olefinically unsaturated double bond. A dispersion stabilizer for suspension polymerization is described.

  In Patent Document 2, a polyvinyl alcohol polymer (B) having a double bond in a side chain, obtained by esterifying a polyvinyl alcohol polymer (A) with a carboxylic acid having an unsaturated double bond or a salt thereof. A dispersion stabilizer consisting of

  However, when a polymerization reaction was carried out using these dispersion stabilizers, a satisfactory effect was not obtained in terms of polymerization stability. Also, the storage stability of the dispersion stabilizer was not sufficient.

  Moreover, since PVA is excellent in film forming property, barrier property with respect to gas etc. and oil resistance can be provided by applying to paper. Paper coated with PVA may be used as barrier paper, and a representative example of barrier paper is release paper base paper. The release paper base paper is usually produced by coating PVA on the paper surface. And a release paper is obtained by forming a release layer (silicone layer) on the surface of this release paper base paper. The PVA in the release paper plays a role of a sealing agent that suppresses the penetration of expensive silicone and platinum into the base paper. In recent years, a coating agent that can accelerate the curing of the silicone of the release layer and improve the adhesion between the PVA layer and the silicone layer in addition to such sealability has been demanded. At this time, when the storage stability and water solubility of PVA are poor, the performance as a coating agent becomes insufficient.

  Patent Document 3 describes a release paper base paper coated with PVA having a silyl group that satisfies specific conditions. When such PVA is applied, a release paper base paper excellent in sealing properties can be obtained. However, the effect of promoting the curing of silicone and the effect of improving the adhesion between the substrate and the silicone layer were insufficient.

  Patent Document 4 describes a cellulose substrate coated with PVA in which a double bond is introduced into a side chain by an acetalization reaction. Usually, since the acetalization reaction uses highly volatile acids such as hydrochloric acid and nitric acid, if such acids remain in the acetalized PVA, it will cause corrosion of the equipment in the coating process, and improvement is desired. It was. In addition, the effect of promoting the curing of the silicone in the release layer was insufficient.

International Publication No. 2015/182567 International Publication No. 2007/119735 JP 2005-194672 A Special table 2013-531136 gazette

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a composition containing polyvinyl alcohol having excellent water solubility and storage stability. It is another object of the present invention to provide a dispersion stabilizer for suspension polymerization that exhibits high polymerization stability when suspension polymerization of a vinyl compound is performed. Furthermore, the present invention provides a coating agent that is excellent in silicone sealability and water resistance in a release paper base paper, promotes the curing of silicone in the release layer, and improves the adhesion between the substrate and the release layer. It is for the purpose.

  The subject is a composition (C) comprising a modified polyvinyl alcohol (A) and a compound (B), wherein the modified polyvinyl alcohol (A) has a double bond derived from an unsaturated carboxylic acid or a derivative thereof. The chain has 0.01 mol% or more and less than 2 mol%, the saponification degree of the modified polyvinyl alcohol (A) is 65 mol% or more, the compound (B) is an alkoxyphenol or a cyclic nitroxyl radical, The composition (C) is characterized in that the content of the compound (B) in the product (C) is 0.001 part by mass or more and less than 5 parts by mass with respect to 100 parts by mass of the modified polyvinyl alcohol (A). It is solved by doing.

  Moreover, the said subject is also solved by providing the manufacturing method of the said composition (C) which makes polyvinyl alcohol (D) react with unsaturated carboxylic acid or its derivative (s) in presence of a compound (B). .

  A powder comprising composition (C) having a yellow index of less than 50 is a preferred embodiment of the present invention. A dispersion stabilizer for suspension polymerization of a vinyl compound containing the composition (C) is also a preferred embodiment of the present invention.

  The object is a method for producing a vinyl polymer in which a vinyl compound is suspension-polymerized in the presence of the composition (C) and the polyvinyl alcohol (E); modified polyvinyl alcohol (A) and polyvinyl alcohol (E) One of these is polyvinyl alcohol having a saponification degree of 77 mol% or more and less than 97 mol% and a viscosity average polymerization degree of 1500 or more and less than 5000, and the other is a saponification degree of 65 mol% or more and less than 77 mol%, and a viscosity average polymerization degree of 400 This can also be solved by providing a production method that is less than 1500 polyvinyl alcohol.

  A coating agent comprising an aqueous solution containing the composition (C) is also a preferred embodiment of the present invention. It is also a preferred embodiment of the present invention to use the coating agent of the present invention as a paper coating agent.

  Further, a release paper base paper obtained by coating the paper with the coating agent of the present invention is also a preferred embodiment of the present invention. Furthermore, a release paper having the release paper base paper and a release layer formed on the surface of the release paper base paper is also a preferred embodiment of the present invention.

  The composition (C) of the present invention is excellent in water solubility and storage stability. Therefore, when a dispersion stabilizer for suspension polymerization containing the composition (C) is used, high polymerization stability is exhibited when the vinyl compound is subjected to suspension polymerization. Moreover, the coating agent containing the composition (C) is excellent in silicone sealing property and water resistance of the release layer base paper, promotes the curing of the silicone in the release layer, and improves the adhesion between the substrate and the release layer. Can be improved.

(Composition (C))
The composition (C) of the present invention may be abbreviated as a modified polyvinyl alcohol (A) having a double bond derived from an unsaturated carboxylic acid or a derivative thereof in the side chain (hereinafter referred to as “modified PVA (A)”). And a specific amount of compound (B). Although the manufacturing method of the composition (C) of this invention is not specifically limited, A suitable manufacturing method makes polyvinyl alcohol (D) react with unsaturated carboxylic acid or its derivative in presence of a compound (B). Is the method. Here, polyvinyl alcohol (D) is PVA which does not have a double bond in a side chain (hereinafter, may be referred to as “PVA (D)” or “raw material PVA”).

(Modified PVA (A))
Raw material PVA (PVA (D)) is obtained by polymerizing a vinyl ester monomer by employing a conventionally known method such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method or a dispersion polymerization method. Can be manufactured. From the industrial viewpoint, preferred polymerization methods are solution polymerization, emulsion polymerization and dispersion polymerization. In the polymerization operation, any one of a batch method, a semi-batch method, and a continuous method can be employed.

  Examples of vinyl ester monomers that can be used for polymerization include vinyl acetate, vinyl formate, vinyl propionate, vinyl caprylate, vinyl versatate, and among these, vinyl acetate is an industrial viewpoint. To preferred.

  When the vinyl ester monomer is polymerized, the vinyl ester monomer may be copolymerized with another monomer as long as the gist of the present invention is not impaired. Examples of monomers that can be used include α-olefins such as ethylene, propylene, n-butene, and isobutylene; acrylic acid and salts thereof, methyl acrylate, ethyl acrylate, n-propyl acrylate, and i-acrylate. Acrylic acid esters such as propyl, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate; methacrylic acid and salts thereof; methyl methacrylate, Methacrylic acid such as ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate Acid S Acrylamide, N-methylacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide, diacetoneacrylamide, acrylamidepropanesulfonic acid and its salt, acrylamidopropyldimethylamine and its salt or quaternary salt thereof, N-methylol Acrylamide derivatives such as acrylamide and derivatives thereof; methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, methacrylamidepropanesulfonic acid and salts thereof, methacrylamidepropyldimethylamine and salts thereof or quaternary salts thereof, N-methylol Methacrylamide derivatives such as methacrylamide and derivatives thereof; methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl Vinyl ethers such as vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether; nitriles such as acrylonitrile and methacrylonitrile; 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; unsaturated dicarboxylic acids such as maleic acid, itaconic acid and fumaric acid, and salts or esters thereof; vinyltrimethoxysilane, etc. Vinylsilyl compounds; isopropenyl acetate and the like. The copolymerization amount of such other monomers is usually 10 mol% or less.

  In the polymerization of the vinyl ester monomer, a chain transfer agent may be allowed to coexist for the purpose of adjusting the degree of polymerization of the resulting polyvinyl ester. Chain transfer agents include aldehydes such as acetaldehyde, propionaldehyde, butyraldehyde and benzaldehyde; ketones such as acetone, methyl ethyl ketone, hexanone and cyclohexanone; mercaptans such as 2-hydroxyethanethiol and dodecyl mercaptan; trichloroethylene and perchloroethylene Halogenated hydrocarbons such as aldehydes and ketones are preferred. The addition amount of the chain transfer agent is determined according to the chain transfer constant of the chain transfer agent to be added and the degree of polymerization of the target polyvinyl ester, but is generally preferably 0.1 to 10% by mass with respect to the polyvinyl ester.

  In the saponification reaction of polyvinyl ester, alcoholysis or hydrolysis reaction using a conventionally known basic catalyst such as sodium hydroxide, potassium hydroxide, sodium methoxide, or acidic catalyst such as p-toluenesulfonic acid is performed. Applicable. Examples of the solvent used for the saponification 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. Can be used alone or in combination of two or more. Among them, it is convenient and preferable to perform the saponification reaction in the presence of sodium hydroxide, which is a basic catalyst, using methanol or a mixed solution of methanol and methyl acetate as a solvent.

  Examples of the unsaturated carboxylic acid or derivative thereof used in the present invention include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, propionic acid, 2-pentenoic acid, 4-pentenoic acid, 2-heptenoic acid, 2-octenoic acid, Cinnamic acid, myristoleic acid, palmitoleic acid, oleic acid, elaidic acid, vaccenic acid, gadoleic acid, erucic acid, nervonic acid, linoleic acid, linolenic acid, eleostearic acid, stearidonic acid, arachidonic acid, eicosapentaenoic acid, Unsaturated monocarboxylic acids such as sardonic acid, docosahexaenoic acid, sorbic acid; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, aconitic acid, mesaconic acid; maleic anhydride, itaconic anhydride, citraconic anhydride Unsaturated carboxylic acid anhydrides such as acids; alkyl acrylates Unsaturated carboxylic acid alkyl esters such as stealth, alkyl methacrylate and crotonic acid; maleic monoalkyl esters such as maleic acid monomethyl ester (monomethyl maleate), fumaric acid monoalkyl esters, itaconic acid monoalkyl esters, citracone Examples thereof include unsaturated dicarboxylic acid monoesters such as acid monoalkyl esters and aconitic acid monoalkyl esters; unsaturated dicarboxylic acid diesters such as maleic acid dialkyl esters, fumaric acid dialkyl esters and itaconic acid dialkyl esters. These carboxylic acids can also be used as salts. Carboxylic acids or their salts can be used alone or in combination of two or more.

  Among these, the unsaturated carboxylic acid or derivative thereof used in the present invention is an unsaturated dicarboxylic acid, an unsaturated carboxylic acid anhydride, or an unsaturated dicarboxylic acid monoester from the viewpoint of reactivity with the hydroxyl group of the raw material PVA. It is preferable. The unsaturated carboxylic acid or a derivative thereof is more preferably maleic anhydride, citraconic acid, itaconic acid or a maleic acid monoalkyl ester from the viewpoint of having a high boiling point to a certain degree and easy handling, and from the viewpoint of reactivity, maleic anhydride, Itaconic acid and maleic acid monoalkyl ester are more preferable, and itaconic acid is particularly preferable.

  It is important that the modified PVA (A) has a double bond derived from an unsaturated carboxylic acid or a derivative thereof in a side chain of 0.01 mol% or more and less than 2 mol%. Here, the modified PVA (A) has a double bond derived from an unsaturated carboxylic acid or a derivative thereof in a side chain of 0.01 mol% or more and less than 2 mol%. It means that it has a double bond derived from an acid or its derivative in the side chain, and the amount of the double bond is 0.01 mol% or more and less than 2 mol% with respect to all monomer units.

  When a vinyl compound is subjected to suspension polymerization using a dispersion stabilizer for suspension polymerization containing a modified PVA (A) having an amount of the above double bond of less than 0.01 mol%, the polymerization stability is reduced and there are many coarse particles. There arises a problem that a polymer having a lot of fish eyes is formed. The amount of the double bond is preferably 0.03 mol% or more. Moreover, when the coating agent containing the modified PVA (A) having an amount of the double bond of less than 0.01 mol% is used, the promotion of silicone curing of the release layer becomes insufficient, and the adhesion between the substrate and the release layer is reduced. The property becomes insufficient. The amount of the double bond is preferably 0.03 mol% or more.

  On the other hand, the modified PVA (A) having a double bond amount of 2 mol% or more is difficult to produce and has low productivity even if it can be produced. The composition (C) containing such a modified PVA (A) has a poor hue, and an insoluble material is formed when dissolved in water. When the vinyl compound is suspension polymerized using a dispersion stabilizer for suspension polymerization containing the modified PVA (A) having a double bond amount of 2 mol% or more, the resulting polymer has a poor hue, and There are also many fish eyes. The amount of the double bond is preferably less than 1.7 mol%. Moreover, when the coating agent containing the modified PVA (A) having a double bond amount of 2 mol% or more is stored for a long period of time, there is a concern that the double bond reacts and gels. The amount of the double bond is preferably less than 1.5 mol%, more preferably less than 1.0 mol%, and even more preferably less than 0.5 mol%. The double bond means a carbon-carbon double bond.

The amount of the double bond derived from the unsaturated carboxylic acid of the modified PVA (A) or a derivative thereof can be measured by a known method. Specifically, measurement by ¹ H-NMR is simple. When measuring the amount of the double bond derived from the unsaturated carboxylic acid or its derivative of the modified PVA (A), it is preferable to remove the unreacted unsaturated carboxylic acid or its derivative in advance and purify it. Although there is no restriction | limiting in particular in the refinement | purification method, The method of wash | cleaning with the solution in which modified | denatured PVA (A) does not melt | dissolve but can dissolve unreacted unsaturated carboxylic acid or its derivative (s) is mentioned. Once the modified PVA (A) is made into an aqueous solution having a concentration of about 1 to 20% by mass, the aqueous solution is dissolved in a solution in which the modified PVA (A) is not dissolved and the unreacted unsaturated carboxylic acid or derivative thereof can be dissolved. A reprecipitation method in which the modified PVA (A) is purified by dripping to precipitate is convenient and preferable.

The viscosity average degree of polymerization of the modified PVA (A) is preferably 400 or more, more preferably 500 or more from the viewpoint of productivity. When used as a dispersion stabilizer for suspension polymerization of a vinyl compound, the modified PVA (A) preferably has a viscosity average polymerization degree of 600 or more. When used as a coating agent, it is preferable that the modified PVA (A) has a viscosity average polymerization degree of 1000 or more. On the other hand, the viscosity average degree of polymerization of the modified PVA (A) is preferably less than 5000, and more preferably less than 3000. When used as a dispersion stabilizer for suspension polymerization of a vinyl compound, the modified PVA (A) preferably has a viscosity average degree of polymerization of less than 1500, and particularly preferably less than 1000. The viscosity average degree of polymerization is a value obtained by measurement according to JIS-K6726. Specifically, when the saponification degree is less than 99.5 mol%, the intrinsic viscosity [η] (liter / liter) measured in water at 30 ° C. is used for the saponified PVA until the saponification degree is 99.5 mol% or more. The viscosity average degree of polymerization (P) was determined by the following formula using g).
P = ([η] × 10 ⁴ /8.29) ^{(1 / 0.62)}

  The degree of saponification of the modified PVA (A) is 65 mol% or more. When it is less than 65 mol%, the solubility of the modified PVA (A) in water decreases. When used as a coating agent, the saponification degree of the modified PVA (A) is preferably 70 mol% or more, more preferably 75 mol% or more, and further preferably 80 mol% or more. On the other hand, the degree of saponification of the modified PVA (A) is usually 99.9 mol% or less. Modified PVA (A) having a saponification degree exceeding 99.9 mol% is difficult to produce. When used as a dispersion stabilizer for suspension polymerization of vinyl compounds, the degree of saponification of the modified PVA (A) is preferably less than 97 mol%, more preferably less than 90 mol%, and more preferably 85 mol%. More preferably, it is more preferably less than 77 mol%. The degree of saponification is a value obtained by measurement according to JIS-K6726.

When used as a coating agent, the modified PVA (A) preferably further has an ethylene unit in the main chain, and the content of the ethylene unit is preferably 1 mol% or more and 10 mol% or less. Here, having an ethylene unit in the main chain means that the modified PVA (A) has a structural unit (— (CH ₂ —CH ₂ ) —) derived from an ethylene monomer in the main chain. Moreover, content of an ethylene unit represents the number of moles of the structural unit derived from ethylene with respect to the number of moles of the monomer unit which comprises the principal chain of modified PVA (A).

  By setting the ethylene unit content to 1 mol% or more, a composition (C) having a more excellent hue can be obtained. Therefore, when a coating agent in which the composition (C) is dissolved in water is applied to a substrate such as paper, there is no possibility that the color tone of the substrate will deteriorate. Moreover, the release paper base paper with a low water absorption can be obtained because content of an ethylene unit shall be 1 mol% or more. The ethylene unit content is more preferably 1.5 mol% or more, and even more preferably 2.5 mol% or more.

  On the other hand, when content of an ethylene unit exceeds 10 mol%, when a composition (C) is dissolved in water, an insoluble matter may be generated. The ethylene unit content is more preferably 8 mol% or less. 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 a raw material PVA. Thus, the raw material PVA having an ethylene unit is obtained by copolymerizing a vinyl ester monomer and ethylene to obtain an ethylene-vinyl ester copolymer, and then saponifying the ethylene-vinyl ester copolymer. Can be obtained.

(Compound (B))
The compound (B) used in the present invention is an alkoxyphenol or a cyclic nitroxyl radical.

  By using alkoxyphenol as the compound (B), a composition (C) having a more excellent hue can be obtained. Here, the alkoxyphenol in the present invention 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. The other hydrogen atom may be substituted with an alkyl group such as a methyl group or an ethyl group or a halogen group, and the number or bonding position thereof is not limited. The number of carbon atoms in 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, and a butoxy group, and among them, a methoxy group is preferable.

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

  Examples of the alkoxyphenol suitably used in the present invention include methoxyphenol, ethoxyphenol, propoxyphenol, butoxyphenol and the like. Among these, from the point of view, methoxyphenol and ethoxyphenol are preferable, and methoxyphenol is more preferable.

  The cyclic nitroxyl radical in the present invention is a compound having a heterocycle formed from a carbon atom and a heteroatom, and the nitrogen atom of the nitroxyl radical (= N-O.) Forms part of the ring. That means. Examples of the hetero atom constituting the ring include an oxygen atom, a phosphorus atom, and a sulfur atom in addition to the nitrogen atom. The number of atoms forming the ring is usually 5 or 6. Substituents such as an alkyl group, a hydroxyl group, a carboxyl group, a sulfo group, and a halogen group may be bonded to the atoms 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 composition (C), since the insoluble matter in water can be further reduced, the cyclic nitroxyl radical is 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) or its A derivative is preferred. As the TEMPO derivative, 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl is preferably used.

(Production method of composition (C))
The composition (C) in the present invention contains a modified polyvinyl alcohol (A) and a compound (B). Although the manufacturing method of a composition (C) is not specifically limited, A suitable manufacturing method makes PVA (D) (raw material PVA), unsaturated carboxylic acid, or its derivative (s) react in presence of a compound (B). Is the method. At this time, in order to promote the reaction, it is preferable to heat the reaction. The heating temperature is preferably 80 to 180 ° C. The heating time is appropriately set in relation to the heating temperature, but is usually 10 minutes to 24 hours.

  As a method of reacting the raw material PVA with the unsaturated carboxylic acid or derivative thereof in the presence of the compound (B), a solution in which the unsaturated carboxylic acid or derivative thereof and the compound (B) are dissolved in a solvent is obtained. Then, after adding the raw material PVA powder to the solution and causing the solution to swell, the mixed powder is obtained by removing the solvent, and the obtained mixed powder is heated. Thus, by making it react in solid in presence of a compound (B), it can suppress that an unwanted crosslinking reaction advances, and can obtain a water-soluble favorable composition (C). . By this reaction method, a powder comprising the composition (C) can be obtained. As the solvent for dissolving the compound (B), alcohol such as methanol, ethanol, propanol or water is used. The removal of the solvent can be performed by heating or depressurizing, preferably by depressurizing.

  In the above reaction method, the content of the unsaturated carboxylic acid or derivative thereof in the mixed powder before heating is preferably 0.01 parts by mass or more with respect to 100 parts by mass of the raw material PVA, and 0.1 parts by mass More preferably, it is more preferably 0.5 parts by mass or more. On the other hand, the content of the unsaturated carboxylic acid or derivative thereof in the mixed powder before heating is preferably 10 parts by mass or less and more preferably 7 parts by mass or less with respect to 100 parts by mass of the raw material PVA. The amount is more preferably 5 parts by mass or less, and particularly preferably 3.5 parts by mass or less. In the composition (C), the raw material PVA contained in the mixed powder before heating becomes the modified PVA (A), and the compound (B) remains as it is.

  In the present invention, it is important that the content of the compound (B) in the composition (C) is 0.001 part by mass or more and less than 5 parts by mass with respect to 100 parts by mass of the modified PVA (A). When content of the compound (B) in a composition (C) is less than 0.001 mass part with respect to 100 mass parts of modified PVA (A), the hue of the composition (C) obtained will deteriorate. Moreover, when a composition (C) is dissolved in water, an insoluble matter is generated. When such a composition (C) is used as a dispersion stabilizer for suspension polymerization of vinyl compounds, the resulting vinyl polymer has a poor hue and a lot of fish eyes. Moreover, when using a composition (C) as a coating agent, the composition (C) obtained that content of a compound (B) is less than 0.001 mass part with respect to 100 mass parts of modified PVA (A). The hue of becomes worse. Therefore, when the coating agent in which the composition (C) is dissolved in water is applied to a substrate such as paper, the color tone of the substrate is deteriorated. Moreover, when a composition (C) is dissolved in water, an insoluble matter is generated. The content of the compound (B) is preferably 0.005 parts by mass or more, more preferably 0.01 parts by mass or more, and 0.05 parts by mass with respect to 100 parts by mass of the modified PVA (A). More preferably, it is the above.

  On the other hand, when the content of the compound (B) in the composition (C) is 5 parts by mass or more with respect to 100 parts by mass of the modified PVA (A), the composition (C) is dispersed for suspension polymerization of the vinyl compound. When used as a stabilizer, the average particle diameter of the resulting vinyl polymer particles is increased, or a large number of coarse particles are formed. Moreover, the fish eye of the obtained vinyl polymer may increase. When the composition (C) is used as a coating agent, the content of the compound (B) is 5 parts by mass or more with respect to 100 parts by mass of the modified PVA (A). B) may bleed out at the interface between the PVA layer and the silicone layer, and adhesion may be reduced. The content of the compound (B) is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, further preferably 2 parts by mass or less, and particularly preferably 1 part by mass or less. preferable.

  The form of the composition (C) is not particularly limited, but is preferably a powder from the viewpoint of the dissolution rate in water. The yellow index (hereinafter sometimes abbreviated as “YI”) of the powder made of the composition (C) is preferably less than 50. When YI is 50 or more, when the composition (C) is used as a dispersion stabilizer for suspension polymerization of a vinyl compound, the hue of the resulting vinyl polymer may be deteriorated. Moreover, when the composition (C) is used as a coating agent and applied to a substrate such as paper, the color tone of the substrate may be deteriorated. From these viewpoints, YI is more preferably 40 or less, and further preferably 30 or less. YI in this specification is a value measured and calculated according to JIS-Z8722 and JIS-K7373.

(Use)
The composition (C) contained in the present invention is used for various applications. Examples thereof are given below, but the invention is not limited to them.
(1) Dispersant use: Dispersion stabilizers for organic and inorganic pigments such as paints and adhesives, and dispersion stabilizers for suspension polymerization of various vinyl compounds such as vinyl chloride, vinylidene chloride, styrene, (meth) acrylate, and vinyl acetate. (2) Coating agents: Paper coating agents, sizing agents, textile finishing agents, leather finishes, paints, antifogging agents, metal corrosion inhibitors, galvanizing brighteners, antistatic agents, pharmaceutical coatings Agents (3) Adhesive applications: Adhesives, adhesives, rewet adhesives, various binders, additives for cement and mortar (4) Emulsifier applications: Emulsifiers for emulsion polymerization, post-emulsifiers such as bitumen (5) Flocculant applications : Flocculant of suspension and dissolved substance in water, metal flocculant (6) Molded product use: fiber, film, sheet, pipe, tube, leak-proof membrane, water-soluble fiber for chemical lace, sponge (7) film use: water-soluble Film, polarizing film, the barrier film (8) Gel Applications: pharmaceutical gels, industrial gels (9) after the reaction Application: Low molecular weight organic compounds, polymer organic compound, a reaction applications after the inorganic compound

(Dispersion stabilizer for suspension polymerization of vinyl compounds)
Among them, a preferred use of the composition (C) of the present invention is a dispersion stabilizer for suspension polymerization of a vinyl compound containing the composition (C). The composition (C) of the present invention has a good hue, and when dissolved in water, formation of insoluble matter is reduced and water solubility is excellent. Therefore, when such a composition (C) is used as a dispersion stabilizer in suspension polymerization of a vinyl compound, the polymerization reaction is stabilized and the formation of coarse particles is reduced. Moreover, coloring and fish eyes of the vinyl polymer obtained can be suppressed.

  The dispersion stabilizer for suspension polymerization may contain various additives other than the modified PVA (A) and the compound (B) as long as the gist of the present invention is not impaired. Examples of the additive include polymerization regulators such as aldehydes, halogenated hydrocarbons, and mercaptans; polymerization inhibitors such as phenol compounds, sulfur compounds, and N-oxide compounds; pH adjusters; cross-linking agents; An antifungal agent, an antiblocking agent, an antifoaming agent, a compatibilizing agent and the like. The content of various additives in the dispersion stabilizer for suspension polymerization is preferably 10% by mass or less, and preferably 5% by mass or less, based on the total amount of the modified PVA (A) and the compound (B). More preferred.

(Method for producing vinyl polymer)
A preferred embodiment of the present invention is a suspension polymerization of a vinyl compound in the presence of the composition (C) of the present invention and polyvinyl alcohol (E) (hereinafter sometimes abbreviated as “PVA (E)”). This is a method for producing a vinyl polymer. Here, the modified PVA (A) and PVA (E) contained in the composition (C) are different in both saponification degree and viscosity average polymerization degree. PVA (E) may be unmodified or modified.

  At this time, any one of the modified PVA (A) and the PVA (E) having a saponification degree and a viscosity average polymerization degree different from that of the modified PVA (A) has a saponification degree of 77 mol% or more and less than 97 mol%, a viscosity PVA having an average polymerization degree of 1500 or more and less than 5000 is preferable, and the other is preferably PVA having a saponification degree of 65 mol% or more and less than 77 mol% and a viscosity average polymerization degree of 400 or more and less than 1500. The saponification degree of PVA is a value that can be measured according to JIS-K6726. The viscosity average degree of polymerization of PVA can be measured according to JIS-K6726, similarly to the modified PVA (A) described above.

  The degree of saponification of the modified PVA (A) is 65 mol% or more and less than 77 mol%, the degree of viscosity average polymerization is 400 or more and less than 1500, the degree of saponification of PVA (E) is 77 mol% or more and less than 97 mol%, the viscosity average polymerization The degree is preferably 1500 or more and less than 5000. By doing in this way, while superposition | polymerization of a vinyl compound is stabilized, coloring and fish eye of the obtained vinyl type polymer can be suppressed more effectively.

  The mass ratio (C / E) between the composition (C) and PVA (E) is preferably 50/50 to 90/10. By setting the mass ratio (C / E) between the composition (C) and PVA (E) within the above range, the polymerization of the vinyl compound becomes more stable, and the resulting vinyl polymer particles have a more uniform particle size. become.

  The dispersion stabilizer for suspension polymerization of the present invention containing the composition (C) and the method for charging PVA (E) into the polymerization tank include (i) PVA (E) and dispersion stability for suspension polymerization of the present invention. (Ii) A dispersion stabilizer for suspension polymerization of the present invention and PVA (E) are prepared as separate aqueous solutions, and then mixed to obtain an aqueous solution after mixing the agent in powder form. (Iii) After preparing the dispersion stabilizer for suspension polymerization of the present invention and PVA (E) as separate aqueous solutions, these are not mixed in the aqueous solution, but separately in the polymerization tank. And (iv) a method of charging the dispersion stabilizer for suspension polymerization of the present invention and PVA (E) in a powder state, but not particularly limited. From the viewpoint of uniformity in the polymerization tank, any of the above methods (i), (ii) and (iii) is preferred.

  Examples of vinyl compounds used in the method for producing a vinyl polymer of the present invention include vinyl halides such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; acrylic acid, methacrylic acid, esters and salts thereof; Examples include acids, fumaric acid, esters and anhydrides thereof; styrene, acrylonitrile, vinylidene chloride, vinyl ether and the like. Among these, the dispersion stabilizer for suspension polymerization of the present invention is particularly preferably used in suspension polymerization of vinyl chloride alone or together with a monomer capable of copolymerizing with vinyl chloride and vinyl chloride. Used. Monomers that can be copolymerized with vinyl chloride include vinyl esters such as vinyl acetate and vinyl propionate; (meth) acrylic esters such as methyl (meth) acrylate and ethyl (meth) acrylate; ethylene, Α-olefins such as propylene; unsaturated dicarboxylic acids such as maleic anhydride and itaconic acid; acrylonitrile, styrene, vinylidene chloride, vinyl ether and the like.

  For suspension polymerization of vinyl compounds, oil-soluble or water-soluble polymerization initiators conventionally used for vinyl chloride polymerization can be used. Examples of the oil-soluble polymerization initiator include percarbonate compounds such as diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, and diethoxyethyl peroxydicarbonate; t-butyl peroxyneodecanate, t -Perester compounds such as butyl peroxypivalate, t-hexyl peroxypivalate, α-cumyl peroxyneodecanate; acetylcyclohexylsulfonyl peroxide, 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate Peroxides such as 3,5,5-trimethylhexanoyl peroxide and lauroyl peroxide; azo compounds such as azobis-2,4-dimethylvaleronitrile and azobis (4-2,4-dimethylvaleronitrile) Raising It is. Examples of the water-soluble polymerization initiator include potassium persulfate, ammonium persulfate, hydrogen peroxide, cumene hydroperoxide, and the like. These oil-soluble or water-soluble polymerization initiators can be used alone or in combination of two or more.

  In the suspension polymerization of the vinyl compound, the polymerization temperature is not particularly limited, and can be adjusted to a high temperature exceeding 90 ° C. as well as a low temperature of about 20 ° C. In order to increase the heat removal efficiency of the polymerization reaction system, a polymerization vessel with a reflux condenser can also be used.

  In suspension polymerization of a vinyl compound, in addition to the composition (C) and PVA (E), methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl which are usually used for suspension polymerization of a vinyl compound in an aqueous medium Water-soluble cellulose ethers such as methyl cellulose; water-soluble polymers such as gelatin; oil-soluble emulsifiers such as sorbitan monolaurate, sorbitan trioleate, glycerin tristearate, ethylene oxide propylene oxide block copolymer; polyoxyethylene sorbitan monolaurate, polyoxy You may use together water-soluble emulsifiers, such as ethyleneglycerin oleate and sodium laurate. Although there is no restriction | limiting in particular about the addition amount, 0.01 mass part or more and 1.0 mass part or less are preferable per 100 mass parts of vinyl compounds.

(Coating agent)
Moreover, the suitable use of the composition (C) of this invention is the coating agent which consists of an aqueous solution containing the said composition (C). The coating agent using the composition (C) of the present invention is excellent in silicone sealing property and water resistance of the release layer base paper, promotes the curing of the silicone in the release layer, and adheres between the substrate and the release layer. Can be improved.

  Although the manufacturing method of the coating agent of this invention is not specifically limited, A suitable manufacturing method makes PVA (D) react with unsaturated carboxylic acid or its derivative (s) in presence of a compound (B), and modified PVA. In this method, a composition (C) containing (A) and the compound (B) is obtained, and then the composition (C) is dissolved in water.

  It is preferable that the coating agent of this invention contains 200 mass parts or more and 100,000 mass parts or less of water as a solvent with respect to 100 mass parts of modified PVA (A). When the amount of water is less than 200 parts by mass, the high-speed coating property tends to decrease. The amount of water is more preferably 400 parts by mass or more, and further preferably 600 parts by mass or more. On the other hand, when the amount of water exceeds 100,000 parts by mass, the coating efficiency tends to decrease. The amount of water is more preferably 50,000 parts by mass or less, and further preferably 10,000 parts by mass or less.

  The coating agent of the present invention may contain other components other than the modified PVA (A), the compound (B) and water as long as the effects of the present invention are not inhibited. Other components 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 , Rice, potato, sweet potato, tapioca, sago palm, etc .; raw starch degradation products such as oxidized starch, dextrin; starch derivatives such as etherified starch, esterified starch, cationized starch; methylcellulose, hydroxyethylcellulose Cellulose derivatives such as carboxymethylcellulose (CMC); monosaccharides such as glucose, fructose, isomerized sugar, xylose; maltose, lactose, sucrose, trehalose, palatinose, reduced maltose, reduced palatinose, reduced milk Disaccharides such as syrup, isomalto-oligosaccharide, fructooligosaccharide, lactose oligosaccharide, soybean oligosaccharide, xylo-oligosaccharide, coupling sugar, cyclodextrin compound, etc .; pullulan, pectin, agar, konjac mannan, polydextrose, xanthan gum Polysaccharides such as albumin, gelatin, casein, gum arabic, polyamide resin, melamine resin, poly (meth) acrylamide, polyvinylpyrrolidone, poly (meth) acrylate sodium, anion-modified PVA, sodium alginate, water-soluble polyester, etc. It is done.

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

  Furthermore, as other components, for example, viscosity modifiers, adhesion improvers, antifoaming agents, plasticizers, water resistance agents, preservatives, antioxidants, penetrants, surfactants, fillers, starches and derivatives thereof, Examples include latex.

  The content of these other components in the coating agent is usually 50 parts by mass or less with respect to 100 parts by mass of the modified PVA (A).

  The coating agent in the present invention can be obtained by dissolving the composition (C) in water. The water (solvent) may contain an alcohol such as methanol, an organic solvent such as acetone, or may contain inorganic particles such as clay that are insoluble in water. The content of components other than water in the solvent is preferably 50% by mass or less, and more preferably 20% by mass or less.

  The base material to which the coating agent of the present invention is applied is not particularly limited, and examples thereof include paper and film. Among them, the substrate on which the coating agent of the present invention is applied is preferably paper.

  A preferred embodiment of the present invention is to use the coating agent as a paper coating agent. As the paper, known paper obtained by papermaking chemical pulp such as hardwood kraft pulp, conifer kraft pulp, mechanical pulp such as GP (crushed wood pulp), RGP (refiner ground pulp), TMP (thermomechanical pulp), etc. Synthetic paper can be used. In addition, as the paper, high-quality paper, medium-quality paper, alkaline paper, glassine paper, semi-glassine paper, or paperboard used for corrugated cardboard, building material, whiteball, chipball, etc., white paperboard, etc. may be used. it can. The paper may contain organic and inorganic pigments and paper making aids such as paper strength enhancers, sizing agents, yield improvers and the like. Further, the paper may be subjected to various surface treatments.

(Release paper base)
A preferred embodiment of the present invention is a release paper base paper obtained by applying the coating agent to paper. When the release layer is formed on the release paper base paper, the coating agent serves as a sealant. That is, the release paper base paper obtained by coating the above coating agent on paper has a sealing layer formed on a substrate. Although the manufacturing method of release paper base paper is not specifically limited, The method provided with the process of applying a coating agent to a base material, and the process of drying a base material after coating is preferable. The paper described above can be used.

The coating liquid can be applied in general coated paper application equipment. For example, a blade coater, an air knife coater, a transfer roll coater, a rod metering size press coater, a curtain coater, a wire bar coater, etc. An on-machine coater or an off-machine coater provided with a processing apparatus can be used to coat the coating liquid in a single layer or multiple layers on the substrate. Moreover, 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 employed. The coating amount is preferably 0.3 to 5.0 g / m ² in terms of dry mass. If the coating amount is less than 0.3 g / m ² , the silicone sealing effect may be reduced. The coating amount is more preferably 0.5 g / m ² or more. On the other hand, when the coating amount exceeds 5.0 g / m ² , the surface area decreases because the sealing layer makes a flat surface on the base material, and even if the silicone layer is formed thereafter, the adhesion with the silicone layer is low. It may not be obtained sufficiently. The coating amount is more preferably 3.0 g / m ² or less.

  In the present invention, as a method for judging the sealing effect of the sealing layer, the air permeability measured using a Wang Ken type lubricity air permeability tester according to JIS-P8117 (2009) can be used. . The air permeability is preferably 2000 sec or more, more preferably 5000 sec or more, still more preferably 10,000 sec or more, and particularly preferably 30000 sec or more. If the air permeability is less than 2000 sec, the sealing effect may be reduced. In addition, it means that an air permeability speed | rate is so large that the value (number of seconds; sec) of an air permeability is small.

In the present invention, the water absorption by the Cobb method according to JIS-P8140 (1998) can be used as an index for judging the water resistance of the sealing layer. The water absorption (60 seconds) is preferably 70 g / m ² or less, more preferably 50 g / m ² or less, and further preferably 40 g / m ² or less.

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

  Further, a release paper having the release paper base paper and a release layer formed on the surface of the release paper base paper is also a preferred embodiment of the present invention. At this time, the release layer contains addition type silicone (F) and platinum (G), and platinum (G) is 0.001 part by mass or more and 0.05 part by mass with respect to 100 parts by mass of addition type silicone (F). It is preferable to contain less than or equal parts. When the blending amount of platinum (G) is in such a range, a release paper having excellent curability can be obtained. When the compounding amount of platinum (G) is less than 0.001 part by mass, the addition type silicone (F) is not sufficiently cured and requires treatment at a high temperature. The compounding amount of platinum (G) is preferably 0.002 parts by mass or more, and more preferably 0.004 parts by mass or more. On the other hand, when the compounding amount of platinum (G) exceeds 0.05 parts by mass, the cost becomes high, which causes a problem in economy. It is preferable that the compounding quantity of platinum (G) is 0.03 mass part or less, and it is more preferable that it is 0.02 mass part or less.

  The addition type silicone (F) used in the present invention comprises an organopolysiloxane (f1) containing at least two carbon-carbon double bonds reactive with SiH groups in one molecule and at least two in one molecule. It is obtained by hydrosilylation reaction with an organohydrogenpolysiloxane (f2) containing SiH groups in the presence of a platinum catalyst.

  Organopolysiloxane (f1) containing at least two carbon-carbon double bonds having reactivity with SiH group in one molecule is vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, isobutenyl group, An organopolysiloxane containing at least two carbon-carbon double bonds such as a hexenyl group in one molecule. Examples of the organopolysiloxane include those having a main chain of a repeating unit of diorganosiloxane and a terminal having a triorganosiloxane structure, and may have a branched or cyclic structure. Examples of the organo group bonded to silicon in the terminal or repeating unit include a methyl group, an ethyl group, and a phenyl group. Specific examples include methylphenyl polysiloxane having vinyl groups at both ends.

  The organohydrogenpolysiloxane (f2) 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. Examples of the organopolysiloxane include those having a main chain of a repeating unit of diorganosiloxane and a terminal having a triorganosiloxane structure, and may have a branched or cyclic structure. Examples of the organo group bonded to silicon in the terminal or repeating unit include a methyl group, an ethyl group, an octyl group, and a phenyl group, and two or more of these are substituted with hydrogen.

  The addition type silicone (F) used in the present invention is appropriately selected from a solvent type, a solventless type, and an emulsion type, but a solventless type addition type silicone is preferable from the viewpoint of reducing environmental burden and coating properties. Adopted. Solvent-free addition-type silicones (F) include SP7015, SP7259, SP7025, SP7248S, SP7268S, SP7030, SP7265S, LTC1006L, LTC1056L and other silicones manufactured by Toray Dow Corning; KNS-3051, KNS-320A, KNS- 316, KNS-3002, KNS-3300, Shin-Etsu Silicone silicones such as X-62-1387; DEHESIVE 920, DEHESIVE 921, DEHESIVE 924, DEHESIVE 927, DEHESIVE 929 silicones; KF-SL101, KF-SL201 Silicones manufactured by Arakawa Chemical Industries, Ltd., such as KF-SL202, KF-SL301, KF-SL302; TPR66 0, such as Momentive Performance Materials Inc. made of silicone, such as SL6625, and the like. These silicones are not necessarily used alone, and may be used in combination of two or more as required.

  A platinum catalyst is usually used for curing the silicone, but the type of platinum catalyst used in the present invention is not particularly limited. Those that cure the addition-type silicone (F) by a hydrosilylation reaction are preferably used. For example, platinum catalysts manufactured by Toray Dow Corning, such as SP7077R and SRX212, and platinum catalysts manufactured by Arakawa Chemical Industries, Ltd., such as CATA93B, can be used. These platinum catalysts are not necessarily used alone, and may be used as a mixture of two or more as required. The amount of platinum (G) is determined by quantifying platinum in the platinum catalyst with an ICP emission spectroscopic analyzer or the like.

  The release layer of the release paper of the present invention may also contain other components other than addition type silicone (F) and platinum (G) as long as the effects of the present invention are not impaired. As a compounding quantity of another component, it is 30 mass parts or less normally with respect to 100 mass parts of peeling layer whole quantity. Other components include, for example, viscosity modifiers, adhesion improvers, antifoaming agents, plasticizers, water resistance agents, preservatives, antioxidants, penetrants, surfactants, inorganic pigments, organic pigments, fillers, Examples thereof include starch and derivatives thereof, cellulose and derivatives thereof, saccharides, latex and the like.

The production method of the release paper of the present invention is not particularly limited, but after applying the coating agent of the present invention on the substrate and forming the sealing layer, platinum (G) with respect to 100 parts by mass of addition-type silicone (F) A method of forming a release layer by coating a coating liquid containing a platinum catalyst prepared so that the blending amount is 0.001 to 0.05 parts by mass on the release layer is preferably employed. Is done. Although the coating amount of the coating liquid containing the platinum catalyst that forms the release layer is not particularly limited, it is preferably 0.1 to 5 g / m ² in terms of solid content. If the coating amount is less than 0.1 g / m ² , the peelability may be inferior. The coating amount is more preferably 0.3 g / m ² or more in terms of solid content. When the coating amount exceeds 5 g / m ² , the adhesion between the release layer containing addition type silicone (F) and platinum (G) and the sealing layer may be lowered. The coating amount is more preferably 3 g / m ² or less in terms of solid content. Various methods are used as the coating method, and a blade coater, an air knife coater, a bar coater and the like are preferable.

  Hereinafter, the present invention will be described in more detail with reference to examples. In the following examples and comparative examples, unless otherwise specified, “part” and “%” represent parts by mass and mass%, respectively.

[Viscosity average polymerization degree of PVA]
The viscosity average degree of polymerization of PVA was measured according to JIS-K6726. Specifically, when the saponification degree is less than 99.5 mol%, the intrinsic viscosity [η] (liter / liter) measured in water at 30 ° C. is used for the saponified PVA until the saponification degree is 99.5 mol% or more. The viscosity average degree of polymerization (P) was determined by the following formula using g).
P = ([η] × 10 ⁴ /8.29) ^{(1 / 0.62)}

[Saponification degree of PVA]
The degree of saponification of PVA was determined by the method described in JIS-K6726. The degree of saponification of the modified PVA (A) is a value measured for the modified PVA (A) isolated by reprecipitation purification of the powder comprising the obtained composition (C).

[Amount of double bond introduced into modified PVA (A)]
A 10% aqueous solution of composition (C) was prepared. 5 g of this aqueous solution was dropped into 500 g of a solution of methyl acetate / water = 95/5 to precipitate the modified PVA (A), which was recovered and dried. About the isolated modified PVA (A), the amount of double bonds introduced into the modified PVA (A) was measured using ¹ H-NMR. The amount of the double bond is the number of moles of double bonds with respect to all monomer units in the modified PVA (A).

[Water-insoluble matter in aqueous solution of composition (C)]
With respect to the 10% aqueous solution of the composition (C) prepared in the measurement of the amount of the double bond introduced into the modified PVA (A), the presence or absence of insoluble matter was visually observed.

Production Example 1 (Production of Composition 1)
A solution prepared by dissolving 0.88 part of maleic anhydride as an unsaturated carboxylic acid and 0.1 part of paramethoxyphenol (hydroquinone monomethyl ether: MEHQ) as a compound (B) in 120 parts of methanol was prepared as a raw material PVA. After adding 100 parts of PVA having a viscosity average polymerization degree of 800 and a saponification degree of 72 mol% and swelling, methanol was removed under reduced pressure. Thereafter, the obtained mixed powder is heat-treated at a temperature of 105 ° C. for 4 hours, whereby a modified PVA (A) having a maleic anhydride-derived double bond in the side chain as a composition (C), and a compound A powdery composition 1 containing (B) was obtained. In the modified PVA (A), a peak of a double bond introduced in the vicinity of 6.0 to 6.5 ppm was confirmed, and the amount of the double bond was 0.12 mol% with respect to the total monomer units. . The modified PVA (A) had a viscosity average polymerization degree of 800 and a saponification degree of 72 mol%. The yellow index (YI) of the powder of composition 1 was 19. When a 10% aqueous solution of Composition 1 was prepared, no insoluble matter was confirmed in the aqueous solution.

Production Examples 2 to 20 (Production of Compositions 2 to 20)
Compositions 2 to 20 were produced in the same manner as in Production Example 1 except that the raw material PVA to be used, the type and amount of unsaturated carboxylic acid or its derivative, the type and amount of compound (B), and the heat treatment temperature were changed. Production conditions and production results are shown in Table 1. In addition, evaluation of the water-insoluble matter in the compositions 10-20 was evaluated by the presence or absence of the insoluble matter when the coating agent was prepared.

[Suspension polymerization of vinyl compounds]
Example 1
The resulting composition 1 was stored at room temperature for 10 days. Thereafter, composition 1 was dissolved in deionized water as a dispersion stabilizer for suspension polymerization, and 100 parts were charged in an autoclave. The density | concentration of the composition 1 in aqueous solution is 650 ppm with respect to the preparation amount of vinyl chloride. Next, as PVA (E), PVA having a viscosity average polymerization degree of 2400 and a saponification degree of 88 mol% was dissolved in deionized water, and 100 parts were charged into an autoclave. The concentration of PVA (E) in the aqueous solution is 100 ppm with respect to the charged amount of vinyl chloride. Next, deionized water was added and charged so that the total amount of deionized water was 1200 parts. Next, 0.65 part of 70% toluene solution of cumylperoxyneodecanoate and 1.05 part of 70% toluene solution of t-butylperoxyneodecaneate are charged into the autoclave, and the pressure is 0.2 MPa in the autoclave. Nitrogen was introduced as follows.

  Thereafter, the operation of purging with nitrogen was carried out five times in total, and after the inside of the autoclave was sufficiently substituted with nitrogen to remove oxygen, 940 parts of vinyl chloride was charged. The content in the autoclave was heated to 57 ° C. and polymerization of vinyl chloride was started with stirring. The pressure in the autoclave at the start of polymerization was 0.80 MPa. After about 3.5 hours from the start of the polymerization, when the pressure in the autoclave reached 0.70 MPa, the polymerization was stopped, unreacted vinyl chloride was removed, the polymerization reaction product was taken out, and 65 ° C. Was dried for 16 hours to obtain vinyl chloride polymer particles. And the particle | grains obtained by the method shown below were evaluated. The evaluation results are shown in Table 2.

(Evaluation of vinyl chloride polymer particles)
About the obtained vinyl chloride polymer particles, (1) average particle diameter, (2) particle size distribution, and (3) fish eye were evaluated according to the following methods. The evaluation results are shown in Table 2.

(1) Average particle diameter The particle size distribution was measured by the dry sieving method described in JIS-Z8815 using a Tyler mesh standard wire mesh. From the results, the average particle size was calculated using the Rosin-Rammler plot.

(2) Particle size distribution The content of JIS standard sieve 42 mesh on was expressed in mass%. The evaluation results are shown in Table 2.
A: Less than 0.5% B: 0.5% or more and less than 1% C: 1% or more

The content of JIS standard sieve 60 mesh on was expressed in mass%. The evaluation results are shown in Table 2.
A: Less than 5% B: 5% or more and less than 10% C: 10% or more

  In addition, both the content of 42 mesh-on and the content of 60 mesh-on indicate that the smaller the value, the smaller the coarse particles, the sharper the particle size distribution, and the better the polymerization stability.

(3) Fisheye 100 parts of the obtained vinyl chloride polymer particles, 50 parts of DOP (dioctyl phthalate), 5 parts of tribasic lead sulfate and 1 part of zinc stearate are roll-kneaded at 150 ° C. for 7 minutes to 0.1 mm. Thick sheets were prepared and the number of fish eyes per 1000 cm ² was measured.

(4) Hue (YI)
100 parts of the obtained vinyl chloride polymer particles, 3 parts of TVS # N-2000E (manufactured by Nitto Kasei), which is a tin stabilizer, and 0.01 part of ultramarine blue at 170 ° C. for 10 minutes at a thickness of 0.4 mm After roll kneading, the obtained sheet was pressed while heating at 185 ° C. and a pressure of 120 kg / cm ² for 5 minutes, and then pressed while cooling at 20 ° C. and a pressure of 150 kg / cm ² for 5 minutes, 42 × A thick film of 25 × 5 mm was produced.

  The hue (YI) of the produced thick film was measured according to JIS-K7105 using a color meter (SM-T-H1 manufactured by Suga Test Instruments). A larger value indicates that the vinyl chloride polymer is decomposed by heat and colored yellow.

Examples 2-6
A suspension polymerization of vinyl chloride was carried out in the same manner as in Example 1 except that the type of the composition (C) used as the dispersion stabilizer for suspension polymerization was changed. The conditions and results are shown in Table 2.

Example 7
After preparing Composition 1, it was stored at room temperature for 12 months. Then, using the composition 1, suspension polymerization of vinyl chloride was carried out in the same manner as in Example 1. The results are shown in Table 2. Even when the composition 1 stored for a long period of time was used, the particle size of the obtained vinyl chloride polymer was small, and the polymerization stability was excellent.

Example 8
After preparing Composition 2, it was stored at room temperature for 12 months. Then, using the composition 2, vinyl chloride suspension polymerization was carried out in the same manner as in Example 1. The results are shown in Table 2. Even when the composition 2 stored for a long time was used, the particle size of the obtained vinyl chloride polymer was small, and the polymerization stability was excellent.

Comparative Example 1
Using composition 7 as composition (C), suspension polymerization of vinyl chloride was attempted in the same manner as in Example 1. However, since the degree of saponification of the modified PVA (A) contained in the composition 7 is too low, it cannot be dissolved in deionized water and cannot be subjected to suspension polymerization of vinyl chloride.

Comparative Example 2
A suspension polymerization of vinyl chloride was carried out in the same manner as in Example 1 except that the composition 8 was used as the composition (C). The results are shown in Table 2. Since composition 8 had a large amount of double bond modification in the modified PVA (A), a vinyl chloride polymer having a small particle size was obtained. However, there were many fish eyes. Further, when a 10% aqueous solution of the composition 8 was prepared, insoluble materials were found in the aqueous solution (Table 1).

Comparative Example 3
A suspension polymerization of vinyl chloride was performed in the same manner as in Example 1 except that the composition 9 was used as the composition (C). The results are shown in Table 2. Since the composition 9 did not contain the compound (B), the particle size distribution of the vinyl chloride polymer was rough, and there were many fish eyes. Further, when a 10% aqueous solution of the composition 9 was prepared, insoluble materials were observed in the aqueous solution (Table 1).

Comparative Example 4
A suspension polymerization of vinyl chloride was performed in the same manner as in Example 1 except that the composition 10 was used as the composition (C). The results are shown in Table 2. The PVA contained in the composition 10 does not have a double bond derived from an unsaturated carboxylic acid or unsaturated carboxylic acid derivative, so the vinyl chloride polymer has a large particle size, a coarse particle size distribution, and a large amount of fish eyes. It became.

Comparative Example 5
After composition 9 was synthesized, it was stored at room temperature for 12 months. Then, using the composition 9, vinyl chloride suspension polymerization was carried out in the same manner as in Example 1. The results are shown in Table 2. When composition 9 stored for 12 months was used, the particle size of the vinyl chloride polymer was large, the particle size distribution was rough, and the fish eyes were considerably large. It has been found that the polymerization stability is considerably lowered when the composition 9 stored for a long time is used.

[Coating agent]
Example 9
The powdery composition 11 was dissolved in water to prepare a coating agent having a concentration of 6% by mass (1560 parts by mass of water with respect to 100 parts by mass of the modified PVA (A)). Moreover, insoluble matter was not confirmed in the aqueous solution. The results are shown in Table 3.

(Manufacture of release paper base paper)
The coating agent was applied to glassine paper having an air permeability of 100 sec using a wire bar so that the coating amount was about 1 g / m ² in terms of dry mass. After coating, the coated paper was obtained by drying at 100 ° C. for 5 minutes. The obtained coated paper was treated twice at 70 ° C. and 400 kg / cm ² with a super calender to obtain a release paper base paper.

(Measurement of air permeability)
In accordance with JIS-P8117, the air permeability of the release paper was measured using an Oken type lubricity air permeability tester. The results are shown in Table 3.

(Cobb water absorption test)
As an index of water resistance of the release paper base, using a Cobb method according to JIS-P8140 (1998), using a water absorption tester (trade name: Gurley Cobb Size Tester, manufactured by Kumagai Riki Kogyo Co., Ltd.) The water absorption for 60 seconds was measured.

(Evaluation of silicone curability)
LTC1056L manufactured by Toray Dow Corning Co. is used as addition type silicone (F), and SRX212CATALYST is used as platinum catalyst (G), so that the ratio of addition type silicone (F) to platinum (G) is 100 / 0.007. The mixed coating solution 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 . In this way, a silicone layer was formed on the release paper base paper. And time until it heat-processes at 110 degreeC and a silicone hardens | cures was measured. Here, the time until the silicone is cured refers to the time (seconds) required until the silicone layer is not peeled off at all by rubbing the silicone layer 10 times with a finger at a predetermined time interval. The results are shown in Table 3.

(Evaluation of adhesion of release layer)
On the release paper base, LTC1056L manufactured by Toray Dow Corning Co., Ltd. is used as the addition type silicone (F), SRX212CATALYST is used as the platinum catalyst (G), and the ratio between the addition type silicone (F) and platinum (G) is 100/0. The coating solution mixed to 0.009 was applied onto the obtained release paper base paper with a blade coater so that the coating solid content was 1.5 g / m ^2, and heat-treated at 110 ° C. for 90 seconds. A release paper having a release layer (silicone layer) formed on the release paper base paper was obtained. The obtained release paper was evaluated with the following indices. The results are shown in Table 3.
A: After standing for 1 week under the conditions of 40 ° C. and 90% RH, the silicone layer was strongly rubbed with a finger. As a result, the silicone layer was not peeled off. After standing for another week under the same conditions, the silicone layer was rubbed with fingers. As a result, the silicone layer was not peeled off.
B: After leaving for 1 week under the conditions of 40 ° C. and 90% RH, the silicone layer was rubbed with fingers. As a result, the silicone layer was not peeled off. However, the silicone layer peeled off when the silicone layer was rubbed with a finger after standing for another week under the same conditions.
C: After being allowed to stand for 1 week under the conditions of 40 ° C. and 90% RH, the silicone layer was strongly rubbed with a finger. As a result, the silicone layer was peeled off.

Examples 10-14, Comparative Examples 6-9
A coating agent was produced in the same manner as in Example 9 except that the type of composition used was changed. Table 3 shows the evaluation results of the obtained coating agent. And the performance of the release paper base paper and the release paper was evaluated in the same manner as in Example 9. The results are shown in Table 3. In Comparative Examples 8 and 9, since insoluble matter was confirmed in the coating agent, the performance evaluation of the release paper base paper and the release paper was not performed.

Claims (9)

A composition (C) comprising a modified polyvinyl alcohol (A) and a compound (B);
The modified polyvinyl alcohol (A) has a double bond derived from an unsaturated carboxylic acid or derivative thereof in a side chain of 0.01 mol% or more and less than 2 mol%,
The degree of saponification of the modified polyvinyl alcohol (A) is 65 mol% or more,
Compound (B) is an alkoxyphenol or a cyclic nitroxyl radical,
Content of compound (B) in composition (C) is 0.001 mass part or more and less than 5 mass parts with respect to 100 mass parts of modified polyvinyl alcohol (A), Composition (C) characterized by the above-mentioned.   The method for producing the composition (C) according to claim 1, wherein the polyvinyl alcohol (D) is reacted with an unsaturated carboxylic acid or a derivative thereof in the presence of the compound (B).   The powder which consists of a composition (C) of Claim 1 whose yellow index is less than 50.   A dispersion stabilizer for suspension polymerization of a vinyl compound, comprising the composition (C) according to claim 1. A method for producing a vinyl polymer, which comprises suspension polymerization of a vinyl compound in the presence of the composition (C) according to claim 1 and polyvinyl alcohol (E);
Either one of the modified polyvinyl alcohol (A) and the polyvinyl alcohol (E) is polyvinyl alcohol having a saponification degree of 77 mol% or more and less than 97 mol%, and a viscosity average polymerization degree of 1500 or more and less than 5000, and the other is a saponification degree of 65 mol. % To less than 77 mol%, and a production method of polyvinyl alcohol having a viscosity average degree of polymerization of 400 to less than 1500.   A coating agent comprising an aqueous solution containing the composition (C) according to claim 1.   The coating agent according to claim 6, which is a paper coating agent.   A release paper base paper obtained by applying the coating agent according to claim 6 to paper.   A release paper comprising the release paper base paper according to claim 8 and a release layer formed on a surface of the release paper base paper.