TW201943743A - Polyvinyl alcohol composition, use thereof, and method for producing vinyl resin - Google Patents

Abstract

A composition (D) containing (A) a modified poly(vinyl alcohol) and (B) an unsaturated monocarboxylic acid or a salt thereof, the composition (D) being characterized in that the modified poly(vinyl alcohol) (A) has a viscosity average polymerization degree of 100 to 600 inclusive and a saponification degree of 33 to 60 mol% inclusive and contains an acryloyl group or a methacryloyl group in an amount of 0.01 to 1.50 mol% inclusive in side chains thereof, the unsaturated monocarboxylic acid or a salt thereof (B) is at least one component selected from the group consisting of acrylic acid, methacrylic acid, sodium acrylate and sodium methacrylate, and the (modified poly(vinyl alcohol) (A))/(unsaturated monocarboxylic acid or a salt thereof (B)) mass ratio in the composition (D) is 82/18 to 99.9/0.1. Thus, a composition is provided, which contains a modified poly(vinyl alcohol) and can exhibit excellent performance as a dispersion stabilizer for the suspension polymerization of a vinyl compound even after a lapse of a long time after the production of the composition.

Description

   Polyvinyl alcohol composition and use thereof, and method for producing vinyl resin   

The present invention relates to a composition (D) containing modified polyvinyl alcohol (A) and an unsaturated monocarboxylic acid or a salt thereof (B). The present invention relates to a dispersion stabilizer for suspension polymerization of a vinyl compound containing the composition (D), and a method for producing a vinyl resin.

Polyvinyl alcohol (hereinafter referred to as "PVA" for short) is a dispersion stabilizer, coating agent, adhesive, polarizing film, water-soluble film, pharmaceutical, cosmetic and other products used for suspension polymerization of vinyl compounds. use. Moreover, it is known that various properties are improved or a special effect is exhibited by the presence of a reactive group such as a double bond in PVA.

Since the double bond has high reactivity, if the PVA is stored for a long time, the double bond may react and gelate. Therefore, in the case of using PVA stored for a long period of time, various performance inferiority becomes a problem.

Examples of applications requiring storage stability of PVA include dispersion stabilizers for suspension polymerization of vinyl compounds. It is considered that the polymerization reaction of a vinyl compound is stabilized by using PVA having a double bond as a dispersion stabilizer for suspension polymerization of a vinyl compound (Patent Documents 1 and 2).

Patent Document 1 describes a dispersion stabilizer for suspension polymerization, which contains polyethylene having a double bond in a side chain, obtained by acetalizing a polyvinyl alcohol polymer with a monoaldehyde having an olefin-based unsaturated double bond. Alcohol-based polymer.

Patent Document 2 describes a dispersion stabilizer comprising a polyvinyl alcohol polymer having a double bond in a side chain, which is obtained by esterifying a polyvinyl alcohol polymer with a carboxylic acid having an unsaturated double bond or a salt thereof. Thing.

However, when such a dispersion stabilizer is used for suspension polymerization of a vinyl compound, the effect which must be satisfied at the point of polymerization stability cannot be obtained. Moreover, the preservation stability of the dispersion stabilizer cannot be said to be sufficient. In addition, in this specification, polymerization stability means that since the dispersibility of droplets containing a vinyl compound during suspension polymerization is good, as a result, an ethylene-based resin in which coarse graining is suppressed and the particle diameter is uniform can be obtained particle.

Prior art literature Patent literature

Patent Document 1 International Publication No. 2015/182567

Patent Document 2 International Publication No. 2007/119735

The present invention has been made in order to solve the above-mentioned problems, and an object thereof is to provide a composition containing modified polyvinyl alcohol which has excellent performance as a dispersion stabilizer for suspension polymerization of vinyl compounds even after a long period of time after production. In addition, it is intended to provide a dispersion stabilizer for suspension polymerization that exhibits high polymerization stability when the vinyl compound is subjected to suspension polymerization, and to provide a small average particle size, less generation of coarse particles, high plasticizer absorption, and fish eyes. The purpose is to suppress the ethylene resin.

The above-mentioned problem can be solved by providing a composition (D) containing a modified polyvinyl alcohol (A) and an unsaturated monocarboxylic acid or a salt thereof (B); and a modified polyvinyl alcohol (A) A composition (D) with an unsaturated monocarboxylic acid or a salt thereof (B), characterized in that the modified polyvinyl alcohol (A) has an average degree of polymerization of 100 to 600 and a degree of saponification of 33 Mo Acryl or methacryl on the side chain of 0.01 to 60 mol% and less than 0.01 mol% and 1.50 mol% or less in the side chain; the unsaturated monocarboxylic acid or its salt (B) is selected from the group consisting of acrylic acid , Methacrylic acid, sodium acrylate and at least one of the group of sodium methacrylate; the mass ratio of the modified polyvinyl alcohol (A) / unsaturated monocarboxylic acid or its salt (B) in the composition (D) It is 82/18 ~ 99.9 / 0.1.

The composition (D) of the modified polyvinyl alcohol (A) having a methacryl group in a side chain is also a preferred embodiment of the present invention.

The composition (D) in which the unsaturated monocarboxylic acid or its salt (B) is methacrylic acid or sodium methacrylate is also a preferred embodiment of the present invention.

The composition (D) further comprising the compound (C) is also a preferred embodiment of the present invention. The compound (C) is selected from the group consisting of the following (C1), (C2), and (C3) At least one type: a compound having a conjugated double bond and having two or more hydroxyl groups bonded to a carbon atom constituting the conjugated double bond, or a salt thereof or an oxide thereof (C1); an alkoxyphenol (C2); And cyclic nitrate free radicals (C3).

A dispersion stabilizer for suspension polymerization of a vinyl compound containing the composition (D) is also a preferred embodiment of the present invention.

A method for producing an ethylene-based resin including a step of performing suspension polymerization of a vinyl compound in the presence of the composition (D) is also a preferred embodiment of the present invention.

The manufacturing method of a polyvinyl alcohol (F) with a viscosity average polymerization degree of 1500 or more and 3500 or less and a saponification degree of 78 mol% or more and less than 92 mol% is also a preferred embodiment of the present invention. .

When a dispersion stabilizer for suspension polymerization containing the composition (D) of the present invention is used, even if it is stored for a long time after manufacture, it exhibits very high polymerization stability when the vinyl compound is subjected to suspension polymerization, and it can provide an average Ethylene resin with small particle size, less formation of coarse particles, high plasticizer absorption, and fisheye suppression.

The form used to implement the invention     (Composition (D))    

The composition (D) of the present invention is characterized in that it contains a specific amount of modified polyvinyl alcohol (A) (A) having a viscosity average polymerization degree and a degree of saponification in a specific range and having an acryl group or a methacryl group in a side chain ( The following will be described as "modified PVA (A)"), and unsaturated monocarboxylic acid or its salt (B).

The mass ratio of the modified PVA (A) / unsaturated monocarboxylic acid or its salt (B) in the composition (D) is 82/18 to 99.9 / 0.1. As will be clearly shown in the comparison between the examples and comparative examples described later, when the mass ratio is less than 82/18, when the composition (D) is used as a dispersion stabilizer for suspension polymerization of a vinyl compound, the plasticizer absorbency is changed. Low, more fish eyes. Therefore, it is important that the aforementioned mass ratio is 82/18 to 99.9 / 0.1. The foregoing mass ratio is preferably 90/10 to 99.8 / 0.2, and more preferably 92/8 to 99.7 / 0.3.

    (Production method of composition (D))    

The composition (D) in the present invention includes modified PVA (A), and at least one unsaturated monocarboxylic acid or a salt thereof selected from the group consisting of acrylic acid, methacrylic acid, sodium acrylate, and sodium methacrylate ( B). The method for producing the composition (D) is not particularly limited, and examples thereof include: (i) Unsaturation of polyvinyl alcohol (E) and an esterification agent in the presence of an unsaturated monocarboxylic acid or a salt thereof (B) A method for reacting a carboxylic acid or a derivative thereof; (ii) After reacting a polyvinyl alcohol (E) with an unsaturated carboxylic acid or a derivative thereof as an esterifying agent, an unsaturated monocarboxylic acid or a salt thereof (B) is added Method. When the polyvinyl alcohol (E) is reacted with an esterifying agent, it is preferable to perform heating in order to promote the reaction. The heating temperature is preferably 80 to 180 ° C. The heating time is appropriately set depending on the relationship with the heating temperature, and is usually 10 minutes to 24 hours. Here, polyvinyl alcohol (E) is a PVA which does not have a double bond in a side chain (it may describe as "PVA (E)" hereafter).

As a method for reacting PVA (E) with an unsaturated carboxylic acid or a derivative thereof as an esterifying agent, it is preferable to obtain a mixed powder by mixing PVA (E) and an unsaturated carboxylic acid or a derivative thereof, and heat Method for the obtained mixed powder. As described above, by reacting an unsaturated carboxylic acid or a derivative thereof in a solid in the presence of an esterifying agent, it is possible to suppress the progress of an undesired crosslinking reaction and to allow the esterification reaction to proceed. By this reaction method, modified PVA (A) can be obtained, and it can be blended with an unsaturated monocarboxylic acid or its salt (B) to obtain a powder containing the composition (D).

In the above reaction method, with respect to 100 parts by mass of PVA (E), the content of the esterifying agent in the mixed powder before heating is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and 0.5 parts by mass The above is particularly good. On the other hand, with respect to 100 parts by mass of PVA (E), the content of the esterifying agent in the mixed powder before heating is preferably 40 parts by mass or less, more preferably 20 parts by mass or less, and 10 parts by mass or less. It is more preferable, and 7 parts by mass or less is particularly preferable.

The form of the composition (D) is not particularly limited, but from the viewpoint of the dissolution rate with respect to the solvent, powder is preferred. The particle diameter of the powder at this time is usually 50 to 2000 μm. The particle diameter of the powder is an average particle diameter determined by a method of JIS-K6726 (1994).

    (Modified PVA (A))    

The modified PVA (A) is synthesized by reacting an esterification agent with PVA (E), and PVA (E) can use vinyl ester monomers by block polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. And a conventionally known method such as a dispersion polymerization method. From an industrial point of view, preferred polymerization methods are a solution polymerization method, an emulsion polymerization method, and a dispersion polymerization method. Regarding the polymerization operation, any of the polymerization methods of batch method, semi-batch method, and continuous method can also be adopted.

Examples of the vinyl ester-based monomer used in the polymerization include vinyl acetate, vinyl formate, vinyl propionate, vinyl octoate, vinyl versatate, and the like from an industrial point of view. It seems that among these, vinyl acetate is more preferable.

When the vinyl ester monomer is polymerized, the vinyl ester monomer and other monomers may be copolymerized as long as the scope of the present invention is not impaired. Examples of usable monomers include α-olefins such as ethylene, propylene, n-butene, and isobutylene; acrylic acid and its salts, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, and n-acrylate Acrylates such as butyl ester, isobutyl acrylate, tertiary butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, and octadecyl acrylate; methacrylic acid and its salts; methyl methacrylate, methyl formate Ethyl acrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tertiary butyl methacrylate, 2-ethylhexyl methacrylate , Methacrylic acid esters such as dodecyl methacrylate, stearyl methacrylate; acrylamide, N-methacrylamide, N-ethylacrylamide, N, N-dimethylacrylamine Acrylamine, diacetone acrylamide, acrylamine propanesulfonic acid and its salts, acrylamide propyldimethylamine and its salts or their quaternary salts, N-methylol acrylamide and its derivatives, etc. Amine derivatives; methacrylamide, N-methacrylamide, N-ethylmethyl Acrylamide, methacrylamine propanesulfonic acid and its salts, methacrylamide propyldimethylamine and its salts or their quaternary salts, N-methylolmethacrylamide and its derivatives, etc. Methacrylamide derivatives; methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tertiary butyl vinyl ether, ten Vinyl ethers such as diethylene vinyl ether and stearyl vinyl ether; nitriles such as acrylonitrile and methacrylonitrile; halogenated ethylene such as vinyl chloride and vinyl fluoride; vinyl halide such as vinyl chloride and vinyl fluoride ; Allyl compounds such as allyl acetate and chloropropene; Unsaturated dicarboxylic acids such as maleic acid, itaconic acid, fumaric acid and their salts or their esters; vinyl silicon compounds such as vinyltrimethoxysilane ; Isopropenyl acetate and the like. The copolymerization amount of such other monomers is usually 10 mol% or less.

In the polymerization of vinyl ester monomers, it is not necessary to coexist a chain transfer agent for the purpose of adjusting the polymerization degree of the obtained polyvinyl ester. Examples of the chain transfer agent include aldehydes such as acetaldehyde, propionaldehyde, butyraldehyde, and benzaldehyde; ketones such as acetone, methyl ethyl ketone, hexanone, and cyclohexanone; 2-hydroxyethyl mercaptan and dodecyl Thiols such as mercaptans; halogenated hydrocarbons such as trichloroethylene and perchloroethylene, among which aldehydes and ketones can be preferably used. The amount of the chain transfer agent to be added may be determined according to the chain transfer constant of the added chain transfer agent and the degree of polymerization of the intended polyvinyl ester, and is usually preferably 0.1 to 10% by mass based on the vinyl ester monomer.

The saponification reaction of a polyvinyl ester is applicable to an alcoholysis or hydrolysis reaction using a conventionally known alkaline catalyst such as sodium hydroxide, potassium hydroxide, and sodium methoxide, or an acid catalyst such as p-toluenesulfonic acid. Examples of the solvent used in 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; and the like They can be used alone or in combination. Among them, it is simple and preferable to use methanol or a mixed solution of methanol and methyl acetate as a solvent, and to perform the saponification reaction in the presence of sodium hydroxide in an alkaline catalyst.

It is important that the modified PVA (A) has a propenyl group or a methacryl group in a side chain of 0.01 mol% or more and 1.50 mol% or less. The modified mass due to acrylfluorenyl or methacrylfluorenyl (hereinafter referred to as "introduction of the amount of modified radicals") can be determined by the content of double bonds in acrylfluorenyl or methacrylfluorenyl Out. The aforementioned double bond means a carbon-carbon double bond. In the case of suspension polymerization of vinyl compounds using suspension stabilizers containing modified PVA (A) with a modified base content of less than 0.01 mol%, the polymerization stability is reduced, large particles are formed, or fish are obtained Eyey vinyl resin. The amount of modified base to be introduced is preferably 0.03 mol% or more. In addition, when the amount of the modified base is more than 1.50 mol%, it is difficult to manufacture, and gelation is liable to occur, and the performance in the case where it is left for a long period of time after manufacturing is reduced. When the composition (D) is used as a dispersion stabilizer for suspension polymerization of a vinyl compound, the plasticizer of the obtained ethylene-based resin has a low absorbency and a large number of fish eyes. The amount of modified base introduced is preferably 1.3 mol% or less, and more preferably 1 mol% or less.

It is important that the double bond of the side chain of the modified PVA (A) is acrylfluorenyl or methacrylfluorenyl, and methacrylfluorenyl is preferred. Other functional groups having a double bond may degrade performance when used as a dispersion stabilizer for suspension polymerization of a vinyl compound.

The amount of the modified base of the modified PVA (A) introduced, that is, the content of the double bond, can be measured by a known method. Specifically, the measurement by ¹ H-NMR is simplified. In the case of measuring the amount of the modified base introduced into the modified PVA (A), a method in which the modified PVA (A) does not dissolve in the solution is washed and then measured. The reprecipitation method is simple and preferable. In the law system, the modified PVA (A) is temporarily made into a solution with a concentration of about 1 to 20% by mass, and then the modified PVA (A) solution is dropped into the solvent in which the modified PVA (A) does not dissolve to make the modified PVA (A ) Precipitate and wash off.

Examples of the unsaturated carboxylic acid or its derivative used in the esterification of PVA (E) include acrylic acid or its salt, methacrylic acid or its salt, methacrylic anhydride, acrylic acid anhydride, alkyl acrylate, methyl Alkyl acrylate. The unsaturated carboxylic acid or its derivative may be used alone or in combination of two or more.

Among these, from the point of view of various application properties when the modified PVA (A) is made, the unsaturated carboxylic acid or its derivative is preferably acrylic anhydride or methacrylic anhydride. From the viewpoint of availability It seems better to use methacrylic anhydride.

The average viscosity of the modified PVA (A) is 100 or more. From the perspective of productivity, it is better to use 120 or more. In the case of using a dispersion stabilizer for suspension polymerization of a vinyl compound, the viscosity average polymerization degree of the modified PVA (A) is more preferably 150 or more. On the other hand, the average viscosity of the modified PVA (A) is 600 or less, and preferably 580 or less. In the case of using a dispersion stabilizer for suspension polymerization of a vinyl compound, the viscosity average polymerization degree of the modified PVA (A) is more preferably 550 or less, and 500 or less is more preferable. The viscosity average degree of polymerization is a value measured in accordance with JIS-K6726 (1994). Specifically, when the degree of saponification is less than 99.5 mol%, for the PVA saponified until the degree of saponification becomes 99.5 mol% or more, the limiting viscosity [η] (liters / g) measured in water at 30 ° C is used. The viscosity average polymerization degree (P) was calculated from the following formula.

P = ([η] × 10 ⁴ /8.29) ^{(1 / 0.62)}

The saponification degree of the modified PVA (A) is above 33 mole%. When the degree of saponification is less than 33 mol%, when a dispersant for suspension polymerization as a vinyl compound is used, the plasticizer absorbency of the obtained vinyl resin becomes low, and fish eyes increase. On the other hand, the saponification degree of the modified PVA (A) is 60 mol% or less. When the modified PVA (A) having a degree of saponification of more than 60 mol% is used as a dispersant for suspension polymerization of a vinyl compound, the plasticizer of the obtained vinyl-based resin has low absorbency and more fish eyes. In the case of using a dispersion stabilizer for suspension polymerization of vinyl compounds, the lower limit of the saponification degree of the modified PVA (A) is preferably 35 mol% or more; the upper limit is preferably 57 mol% or less, 54 Molar% is more preferred. The degree of saponification is a value measured in accordance with JIS-K6726 (1994).

    (Unsaturated monocarboxylic acid or its salt (B))    

It is important that the composition (D) of the present invention contains at least one unsaturated monocarboxylic acid or a salt (B) thereof selected from the group consisting of acrylic acid, methacrylic acid, sodium acrylate, and sodium methacrylate. Other unsaturated monocarboxylic acids or salts thereof may reduce various properties when the composition (D) is stored for a long period of time. In particular, when the composition (D) is used as a dispersion stabilizer for suspension polymerization of a vinyl compound, the particle size of the obtained vinyl resin becomes larger, the particle size distribution becomes wider, the plasticizer absorbency becomes lower, and the fisheye becomes larger. . The unsaturated monocarboxylic acid or its salt (B) is preferably methacrylic acid or sodium methacrylate.

    (Compound (C))    

The composition (D) of the present invention preferably further comprises a compound (C), and the compound (C) is at least one selected from the group consisting of the following (C1), (C2), and (C3): A compound having a conjugated double bond and having two or more hydroxyl groups bonded to a carbon atom constituting the conjugated double bond, or a salt thereof or an oxide thereof (C1); an alkoxyphenol (C2); and a cyclic nitrate醯 Free radicals (C3).

Regarding a compound having a conjugated double bond and having two or more hydroxyl groups bonded to a carbon atom constituting the conjugated double bond, or a salt thereof or an oxide thereof (C1), the conjugated double bond defined herein includes: Conjugation due to carbon-carbon double bonds, conjugation due to carbon-heteroatom double bonds, conjugation due to aromatic compounds. As an example of a compound having a conjugated double bond and two or more hydroxyl groups bonded to a carbon atom constituting the conjugated double bond, or a salt thereof or an oxide (C1) thereof, catechol, tertiary Butylhydroquinone, 2,6-bis (tertiary butyl) hydroquinone, pyrrogallol, 1,3,5-trihydroxybenzene, hexahydroxybenzene; gallic acid or salts thereof; gallic Methyl gallate, ethyl gallate, propyl gallate, octyl gallate, dodecyl gallate and other alkyl gallates; epicatechin, epigalloate Catechins such as epigallocatechin, epigallocatechin-3-gallate; ascorbic acid or salts thereof; benzoquinone; dehydroascorbic acid, etc. Among them, a compound having two or more hydroxyl groups bonded to a carbon atom constituting a conjugated double bond is more preferable, and a compound having two or more phenolic hydroxyl groups is more preferable.

The alkoxyphenol (C2) in the present invention refers to a compound in which at least one hydrogen atom of a benzene ring is substituted with an alkoxy group and at least one hydroxyl group is substituted. Other hydrogen atoms may be substituted with alkyl and halogen groups such as methyl and ethyl, and the number and bonding position are not limited. The carbon number of the alkoxy group is usually 10 or less, and 8 or less is preferable, 6 or less is more preferable, 4 or less is more preferable, and 2 or less is particularly preferable. It does not matter whether the carbon chain of the alkoxy group is linear or branched, and from the viewpoint of availability, it is preferable that it is linear. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, and a butoxy group. Among them, a methoxy group is more preferable.

The alkoxyphenol (C2) used in the present invention is preferably a compound in which one hydrogen atom of a benzene ring is substituted with an alkoxy group and one hydroxyl group is substituted. At this time, the bonding position of the alkoxy group is not particularly limited, and from the viewpoint of availability, the ortho or para position is preferable, and the para position is more preferable.

Examples of the alkoxyphenol (C2) to which the present invention is applicable include methoxyphenol, ethoxyphenol, propoxyphenol, and butoxyphenol. Among them, methoxyphenol is more preferable from the viewpoint of obtainability.

The cyclic nitrate radical (C3) in the present invention refers to a compound having a heterocyclic ring formed by a carbon atom and a hetero atom, and a nitrogen atom of the nitrate radical (= N-O‧) forming a part of the ring. Examples of the hetero atom constituting the ring include an oxygen atom, a phosphorus atom, and a sulfur atom in addition to a nitrogen atom. The number of atoms forming a ring is usually five or six. It is also possible to have substituents such as an alkyl group, a hydroxyl group, a carboxyl group, a sulfonic acid group, and a halogen group bonded to the ring-forming atom. The number of substituents and the bonding position of the substituents are not particularly limited, and plural substituents may be bonded to the same or different atoms. From the viewpoint of availability, the above cyclic nitrate free radical is preferably 2,2,6,6-tetramethylpiperidine 1-oxide (2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO )) Or a derivative thereof. As a TEMPO derivative, 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxide can be applied.

From the viewpoint of availability, the compound (C) is preferably a compound having a conjugated double bond and having two or more hydroxyl groups bonded to a carbon atom constituting the conjugated double bond, or a salt thereof or an oxidation thereof (C1); or alkoxyphenol (C2), more preferably a compound having a conjugated double bond and having two or more hydroxyl groups bonded to a carbon atom constituting the conjugated double bond, or a salt thereof or an oxidation thereof物 (C1).

    (Use)    

The composition (D) of the present invention can be used in various applications. Examples are listed below but are not limited thereto.

(1) Use of dispersant: dispersion stabilizer for organic and inorganic pigments such as paints and adhesives, suspension polymerization of various vinyl compounds such as vinyl chloride, vinyl chloride, styrene, (meth) acrylate, vinyl acetate, etc. Dispersing stabilizer and dispersing aid

(2) Coating agent application: paper coating agent, sizing agent, fiber processing agent, leather finishing agent, coating, anti-fogging agent, anti-metal corrosion agent, galvanizing gloss agent, anti-static agent

(3) Adhesive applications: adhesives, adhesives, rewetting adhesives, various adhesives, additives for cement or mortar

(4) Use of emulsifier: emulsifier for emulsification polymerization, emulsifier after asphalt, etc.

(5) Use of agglutinating agent: agglutinating agent for suspended matter and dissolved matter in water, metal agglutinating agent

(6) Paper processing applications: paper strength enhancer, oil resistance and solvent resistance imparting agent, smoothness improving agent, surface gloss improving additive, filler, barrier, light resistance imparting agent, water resistance agent, dye and color developer dispersion Agent, adhesion improver, adhesive

(7) Agricultural use: adhesives for pesticides, spreading agents for pesticides, agricultural coatings, soil improvers, anti-erosion agents, pesticide dispersants

(8) Medical and Cosmetics Applications: Granulating adhesives, coating agents, emulsifiers, adhesives, binding agents, film preparation substrates, film forming agents

(9) Viscosity adjuster use: thickener, rheology adjuster

(10) Film use: water-soluble film, polarizing film, barrier film, film for packaging fiber products, seed curing sheet, vegetative sheet, seed tape, hygroscopic film

(11) Uses of molded articles: fibers, pipes, tubes, leak-proof membranes, water-soluble fibers for chemical lace, sponges

(12) Gel use: medical gel, industrial gel

(13) Post-reaction use: post-reaction use with low-molecular organic compounds, high-molecular organic compounds, and inorganic compounds

Among them, the composition (D) of the present invention is applicable to the use of (1) a dispersant as described later.

    (Dispersion stabilizer for suspension polymerization of vinyl compounds)    

The suitable application of the composition (D) of the present invention is a dispersion stabilizer for suspension polymerization of a vinyl compound containing the composition (D). When the composition (D) of the present invention is used as a dispersion stabilizer in suspension polymerization of a vinyl compound, even if it is stored for a long period of time, the performance is high, the polymerization reaction is stable, and the formation of coarse particles is reduced. Further, an ethylene-based resin having a high plasticizer absorbency and few fish eyes can be obtained.

The said dispersion stabilizer for suspension polymerization can contain various additives in the range which does not impair the meaning of this invention. Examples of the additives include polymerization regulators such as aldehydes, halogenated hydrocarbons, and thiols; polymerization inhibitors such as phenol compounds, sulfur compounds, and N-oxide compounds; pH regulators; cross-linking agents; and preservatives; Antifungal agent; antiblocking agent; antifoaming agent; compatibilizer and so on. The content of various additives in the dispersion stabilizer for suspension polymerization is preferably 10% by mass or less, and more preferably 5% by mass or less with respect to the total amount of the composition (D).

    (Manufacturing method of vinyl resin)    

A preferred embodiment of the present invention is a method for producing an ethylene-based resin by subjecting a vinyl compound to suspension polymerization in the presence of the composition (D) of the present invention. In addition, a preferred embodiment of the present invention is in the presence of the composition (D) of the present invention, and the average degree of polymerization is 1500 or more and 3500 or less, and the degree of saponification is 78 or more and less than 92 mol%. A method for producing a vinyl resin (F) and a vinyl resin by suspension polymerization of a vinyl compound. Polyvinyl alcohol (F) having a degree of polymerization and a degree of saponification in the above ranges is preferred from the viewpoint of high polymerization stability. In addition, the manufacturing method of polyvinyl alcohol (F) can be suitably adjusted according to the manufacturing method of said PVA (E). The use amount of polyvinyl alcohol (F) is preferably 10 to 1000% by mass based on the total amount of the composition (D).

Examples of the vinyl compound used in the method for producing an ethylene-based resin of the present invention include: halogenated ethylene such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; acrylic acid, methacrylic acid, and the like and salts thereof ; Maleic acid, fumaric acid, these esters and anhydrides; styrene, acrylonitrile, vinylidene chloride, vinyl ether, etc. Among them, vinyl chloride alone or a combination of vinyl chloride and a monomer copolymerizable with vinyl chloride is preferred. Examples of the monomer copolymerizable with vinyl chloride include vinyl esters such as vinyl acetate and vinyl propionate; (meth) acrylates such as methyl (meth) acrylate and ethyl (meth) acrylate; and ethylene Α-olefins such as propylene and propylene; unsaturated dicarboxylic acids such as maleic anhydride and iconic acid; acrylonitrile; styrene; vinyl chloride; vinyl ether and the like.

For the suspension polymerization of a vinyl compound, an oil-soluble or water-soluble polymerization initiator conventionally used for the polymerization of vinyl chloride can be used. Examples of the oil-soluble polymerization initiator include peroxycarbonate compounds such as diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, and diethoxyethyl peroxydicarbonate. ; Peroxy neodecanoic acid tert-butyl ester, peroxytrimethylacetic acid tert-butyl ester, peroxytrimethylacetic acid tert-hexyl ester, peroxy neodecanoic acid α-cumyl ester and other peroxy acid ester compounds ; Acetylcyclohexylsulfofluorenyl peroxide, 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate, 3,5,5-trimethylhexyl peroxide, Peroxides such as lauryl peroxide, azobis-2,4-dimethylvaleronitrile, azobis (4-2,4-dimethylvaleronitrile), and other azo compounds. Examples of the water-soluble polymerization initiator include potassium persulfate, ammonium persulfate, hydrogen peroxide, cumene hydroperoxide, and the like. These polymerization initiators may be used alone or in combination of two or more.

In the suspension polymerization of a vinyl compound, the polymerization temperature is not particularly limited, and may be about 20 ° C or more than 90 ° C. In order to improve the heat removal efficiency of the polymerization reaction system, a polymerizer with a reflux condenser may be used.

In the suspension polymerization of a vinyl compound, in addition to the composition (D), it may be used in combination: methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose commonly used in suspension polymerization of a vinyl compound in an aqueous medium Water-soluble cellulose ethers such as hydroxypropyl methylcellulose; water-soluble polymers such as gelatin; sorbitan monolaurate, sorbitan trioleate, glyceryl tristearate, ethylene oxide ring Oil-soluble emulsifiers such as oxypropane block copolymers; water-soluble emulsifiers such as polyoxyethylene sorbitan monolaurate, polyoxyethylene ethyl glyceryl oleate, and sodium laurate. The amount of addition is not particularly limited, but it is preferably 0.01 to 1.0 parts by mass per 100 parts by mass of the vinyl compound.

    [Example]    

Hereinafter, the present invention will be described in more detail through examples. In the following examples and comparative examples, unless otherwise specified, "part" and "%" represent mass parts and mass%, respectively.

    [Viscosity average polymerization degree of PVA]    

The viscosity average polymerization degree of PVA is measured in accordance with JIS-K6726 (1994). Specifically, when the degree of saponification is less than 99.5 mol%, for the PVA saponified until the degree of saponification becomes 99.5 mol% or more, the limiting viscosity [η] (liters / g) measured in water at 30 ° C is used. The viscosity average polymerization degree (P) was calculated from the following formula. The saponification degree of the modified PVA (A) is a value measured for the modified PVA (A) separated by reprecipitation and purification of the powder containing the obtained composition (D).

P = ([η] × 10 ⁴ /8.29) ^{(1 / 0.62)}

    [Saponification degree of PVA]    

The degree of saponification of PVA is determined by the method described in JIS-K6726 (1994). The saponification degree of the modified PVA (A) is a value measured with respect to the modified PVA (A) obtained by reprecipitating and refining a powder containing the obtained composition (D).

    [Imported base of modified PVA (A)]    

A 10% methyl acetate solution of the composition (D) was prepared. 5 g of this aqueous solution was dropped into 500 g of water, and the modified PVA (A) was precipitated, recovered and dried. With respect to the isolated modified PVA (A), the amount of double bonds introduced into the modified PVA (A) was measured by ¹ H-NMR, and the amount of the modified base introduced was determined. In addition, the amount of the double bond is the mole number of the double bond with respect to the total monomer unit in the modified PVA (A).

    Manufacture of composition 1    

4.6 parts of methacrylic anhydride as an esterifying agent, and 0.3 parts of tertiary butyl hydroquinone as compound (C) were added to 100 parts of a viscosity average polymerization degree of 250 and a saponification degree of 45 mole% of PVA (E ) To obtain a mixed powder. The obtained mixed powder was heat-treated at a temperature of 120 ° C for 6 hours, and then 1.5 parts of methacrylic acid was added as an unsaturated monocarboxylic acid or a salt thereof (B). PVA (A), unsaturated monocarboxylic acid or its salt (B), and powdery composition 1 of compound (C). The amount of the unsaturated monocarboxylic acid or its salt (B) used is an amount based on 100 parts of the modified PVA (A). In the above-mentioned modified PVA (A), a peak of a double bond to be introduced was confirmed around 6.0 to 6.5 ppm, and the amount of the modified base introduced was 0.23 mole% relative to the total monomer unit. The viscosity average polymerization degree of the modified PVA (A) was 250, and the saponification degree was 45 mole%. The mass ratio of the modified PVA (A) / unsaturated monocarboxylic acid or its salt (B) in the composition 1 was 98.5 / 1.5.

    Manufacture of composition 2 ~ 13    

Except changing the types and amounts of PVA (E), esterifying agent, compound (C), unsaturated monocarboxylic acid or its salt (B), and heat treatment conditions as shown in Tables 1 and 2, it is the same as Composition 1 Production was carried out in the same manner, and compositions 2 to 13 were produced. The conditions and results are shown in Tables 1 and 2.

    Example 1    

As a suspension polymerization test of a vinyl compound, Composition 1 which was left at 50 ° C. for 6 months after production was dissolved in methanol as a dispersion stabilizer for suspension polymerization, and 10 parts were charged into an autoclave. The concentration of the composition 1 in the methanol solution was 500 ppm with respect to the input amount of vinyl chloride. Next, as a PVA used in combination, PVA having an average viscosity of 2000 and a saponification degree of 80 mol% was dissolved in deionized water and 100 parts were added. The concentration of PVA used together was 800 ppm relative to the amount of vinyl chloride added. Next, additional deionized water was added so that the total of the deionized water became 1,200 parts. Next, put 0.65 parts of a 70% toluene solution of cumene peroxyneodecanoate and 1.05 parts of a 70% toluene solution of tert-butyl peroxyneodecanoate into the autoclave. 0.2 MPa of nitrogen was introduced. Thereafter, the nitrogen flushing operation was performed five times in total, and the inside of the autoclave was sufficiently substituted with nitrogen to remove oxygen, and then 940 parts of vinyl chloride was charged. The contents of the autoclave were heated to 57 ° C and suspension polymerization of vinyl chloride was started with stirring. The pressure in the autoclave at the start of the polymerization was 0.80 MPa. After about 3.5 hours from the start of polymerization, the polymerization was stopped when the pressure in the autoclave reached 0.70 MPa. After removing unreacted vinyl chloride, the polymerization reaction product was taken out and dried at 65 ° C for 16 hours to obtain chlorine. Ethylene polymer particles.

    (Evaluation of vinyl chloride polymer particles)    

About the obtained vinyl chloride polymer particles, (1) average particle diameter, (2) particle size distribution, (3) plasticizer absorbability, and (4) fisheye were evaluated by the following methods. The evaluation results are shown in Table 2.

    (1) average particle size    

Using a metal mesh based on Tyler mesh, the particle size distribution was measured by the dry sieve method described in JIS-Z8815 (1994). From this result, the average particle diameter was calculated using a Rosin-Rammler plot.

    (2) Particle size distribution    

The content of 42 meshes that cannot pass the JIS standard sieve is expressed in mass%.

A: less than 0.5%

B: 0.5% or more and less than 1%

C: 1% or more

The content of 60 meshes that cannot pass the JIS standard sieve is expressed in mass%.

A: less than 5%

B: more than 5% and less than 10%

C: 10% or more

In addition, the content that cannot pass through 42 meshes and the content that cannot pass through 60 meshes are both smaller in value and smaller in coarse particles and narrower in particle size distribution, showing excellent polymerization stability. Among the above particle size distributions, A and B are usable levels.

    (3) Plasticizer absorption    

Weigh the mass (A (g)) of a 5mL syringe filled with 0.02g of absorbent cotton, put 0.5g of vinyl chloride polymer particles into it and weigh the mass (B (g)), put 1g of After dioctyl phthalate (DOP) was left to stand for 15 minutes, centrifugation was performed at 3000 rpm for 40 minutes and the mass (C (g)) was measured. Then, the plasticizer absorptivity (%) was calculated | required by the following calculation formula. The higher the absorbency of the plasticizer, the easier it is to process, mainly because it is difficult to cause defects in the appearance of articles and the like when it is processed into a sheet.

Plasticizer absorption (%) = 100 × [((C-A) / (B-A))-1]

    (4) 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 were heated at 150 ° C. Next, roller kneading was performed for 7 minutes to prepare a 0.1 mm thick sheet, and the number of fish eyes per 1000 cm ² was measured.

    Examples 2 to 5    

Using the obtained compositions 2 to 5, a suspension polymerization test of a vinyl compound was performed. A suspension polymerization of vinyl chloride was carried out in the same manner as in Example 1 except that the composition (D) used as a dispersion stabilizer for suspension polymerization was changed to that shown in Table 2. Table 2 shows the conditions and evaluation results of the obtained vinyl chloride polymer particles.

    Comparative Example 1    

The obtained composition 6 was used for suspension polymerization of a vinyl compound in the same manner as in Example 1. The composition 6 does not contain an unsaturated monocarboxylic acid or a salt thereof (B). The vinyl chloride polymer particles have a large particle size, a wide particle size distribution, a low plasticizer absorption, and a large number of fish eyes. The conditions and results are shown in Table 2.

    Comparative Example 2    

The obtained composition 7 was used for suspension polymerization of a vinyl compound in the same manner as in Example 1. Since the unsaturated monocarboxylic acid or its salt (B) contained in the composition 7 is oleic acid, the vinyl chloride polymer particles have a large particle size, a wide particle size distribution, a low plasticizer absorbency, and many fish eyes. The conditions and results are shown in Table 2.

    Comparative Example 3    

The obtained composition 8 was used for suspension polymerization of a vinyl compound in the same manner as in Example 1. Since the saponification degree of the modified PVA (A) in the composition 8 is too high, the plasticizer has low absorbency and many fish eyes. The conditions and results are shown in Table 2.

    Comparative Example 4    

The obtained composition 9 was used for suspension polymerization of a vinyl compound in the same manner as in Example 1. Since the degree of polymerization of the modified PVA (A) in the composition 9 is too high and the degree of saponification is too low, the absorbency of the plasticizer is low and there are many fish eyes. The conditions and results are shown in Table 2.

    Comparative Example 5    

The obtained composition 10 was used for suspension polymerization of a vinyl compound in the same manner as in Example 1. Since the composition 10 does not include modified PVA (A), the vinyl chloride polymer particles have a large particle size, a wide particle size distribution, a low plasticizer absorption, and a large number of fish eyes. The conditions and results are shown in Table 2.

    Comparative Example 6    

The obtained composition 11 was used for suspension polymerization of a vinyl compound in the same manner as in Example 1. Since the side chain of the modified PVA (A) contained in the composition 11 is a maleinyl group, the vinyl chloride polymer particles have a large particle size, a wide particle size distribution, a low plasticizer absorption, and many fish eyes. The conditions and results are shown in Table 2.

    Comparative Example 7    

The obtained composition 12 was used for suspension polymerization of a vinyl compound in the same manner as in Example 1. Since the composition 12 contains too much unsaturated monocarboxylic acid or its salt (B), it has a wide particle size distribution, low plasticizer absorption, and many fish eyes. The conditions and results are shown in Table 2.

    Comparative Example 8    

Except that the obtained composition 13 was used, and the type of PVA used in combination was changed, it was used for suspension polymerization of a vinyl compound in the same manner as in Example 1. Since the modified PVA (A) contained in the composition 13 has too much modified mass, it is a result that the plasticizer has low absorbency and many fish eyes. The conditions and results are shown in Table 2.

As shown in the examples, when the composition (D) of the present invention uses a dispersion stabilizer for suspension polymerization as a vinyl compound, it has excellent polymerization stability even after a long period of time after production, and can provide an average particle diameter. Ethylene-based resin with small and coarse particle formation, high plasticizer absorption, and fisheye suppression. Therefore, the present invention is extremely industrially useful.

Claims (7)

    A composition (D), which is a composition (D) containing modified polyvinyl alcohol (A) and an unsaturated monocarboxylic acid or a salt thereof (B); characterized in that the modified polyvinyl alcohol (A) is The viscosity average polymerization degree is 100 or more and 600 or less, the saponification degree is 33 or more and 60 or less, and the side chain has acryl or methacryl on the side chain of 0.01 or more and 1.50 or less. The saturated monocarboxylic acid or its salt (B) is at least one selected from the group consisting of acrylic acid, methacrylic acid, sodium acrylate, and sodium methacrylate, and the modified polyvinyl alcohol (A) in the composition (D) The mass ratio of the unsaturated monocarboxylic acid or its salt (B) is 82/18 to 99.9 / 0.1.         The composition (D) according to claim 1, wherein the modified polyvinyl alcohol (A) has a methacrylfluorenyl group in a side chain.         The composition (D) of claim 1 or 2, wherein the unsaturated monocarboxylic acid or its salt (B) is methacrylic acid or sodium methacrylate.         If the composition (D) of claim 1 or 2 further comprises a compound (C), the compound (C) is at least one selected from the group consisting of the following (C1), (C2), and (C3) : A compound having a conjugated double bond and having two or more hydroxyl groups bonded to a carbon atom constituting the conjugated double bond, or a salt thereof or an oxide thereof (C1); an alkoxyphenol (C2); and a ring Nitrate free radical (C3).         A dispersion stabilizer for suspension polymerization of a vinyl compound, comprising the composition (D) according to any one of claims 1 to 4.         A method for producing an ethylene-based resin, comprising the step of performing suspension polymerization of a vinyl compound in the presence of the composition (D) according to any one of claims 1 to 4.         For example, the method for producing an ethylene-based resin according to claim 6, wherein the polyvinyl alcohol (F) having a viscosity average polymerization degree of 1,500 or more and 3500 or less and a saponification degree of 78 mol% or more and less than 92 mol% is used in combination.