Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K23/00—Use of substances as emulsifying, wetting, dispersing, or foam-producing agents
  • C09K23/52—Natural or synthetic resins or their salts
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F2/00—Processes of polymerisation
  • C08F2/12—Polymerisation in non-solvents
  • C08F2/16—Aqueous medium
  • C08F2/18—Suspension polymerisation
  • C08F2/20—Suspension polymerisation with the aid of macromolecular dispersing agents
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F261/00—Macromolecular compounds obtained by polymerising monomers on to polymers of oxygen-containing monomers as defined in group C08F16/00
  • C08F261/06—Macromolecular compounds obtained by polymerising monomers on to polymers of oxygen-containing monomers as defined in group C08F16/00 on to polymers of unsaturated ethers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F8/00—Chemical modification by after-treatment
  • C08F8/12—Hydrolysis

Definitions

• the present invention relates to a modified vinyl alcohol polymer and a method for producing the same.
• the present invention also relates to a dispersion stabilizer for suspension polymerization, particularly a dispersion stabilizer suitable for suspension polymerization of vinyl compounds, especially vinyl chloride.
• the present invention also relates to a method for producing a vinyl resin using a dispersion stabilizer for suspension polymerization.
• dispersion stabilizers such as polyvinyl alcohol, methylol Dispersion stabilizers such as cellulose are used, among which polyvinyl alcohol (PVA) has excellent properties and is most commonly used.
• PVA polyvinyl alcohol
• a dispersion stabilizer for suspension polymerization of a vinyl compound a specific carboxylic acid ester group or a carbonyl group derived from an aldehyde is introduced into a polyvinyl alcohol polymer, and undergoes a dehydration reaction or a deacetic acid reaction during saponification.
• a method of introducing an unsaturated double bond, a method of using a modified PVA having a specific oxyalkylene group in the side chain, and the like have been proposed (eg, Patent Documents 1 to 4).
• the present invention provides a dispersion suitable for obtaining resin particles that are stably fine and highly uniform in particle size under a wide range of stirring conditions when suspension polymerization of a vinyl compound such as vinyl chloride is performed.
• One object of the present invention is to provide a modified vinyl alcohol polymer useful as a stabilizer.
• a side chain has a predetermined polyoxyalkylene unit
• a main chain terminal has a predetermined carbonyl unit
• a predetermined carbonyl unit is present in the main chain. It has been found that it is effective to use a modified vinyl alcohol polymer having a dicarboxylic acid unit of
• the side chain has a polyoxyalkylene unit represented by general formula (I), the main chain terminal has a carbonyl unit represented by general formula (II), and the main chain has general formula (III ) is a modified vinyl alcohol polymer having a dicarboxylic acid unit shown in ).
• R 1 and R 2 are each independently a hydrogen atom, a methyl group or an ethyl group, R 3 is a hydrogen atom or a methyl group, n represents the number of repeating units, and is an integer of 1 ⁇ n ⁇ 70 .
• A represents a hydrogen atom or an alkyl group having 1 to 9 carbon atoms.
• X and Y each independently represent an alkyl group having 1 to 12 carbon atoms, a hydrogen atom or a metal atom.
• a monomer having a polyoxyalkylene unit represented by general formula (I) in a side chain is The ratio of the number of moles of the mer unit is 0.01 mol% to 5.0 mol%, and the ratio of the number of moles of the carbonyl unit represented by the general formula (II) is 0.01 mol% to 1.0 mol%. and the ratio of the number of moles of the dicarboxylic acid unit represented by the general formula (III) is 0.01 mol % to 0.5 mol %.
• At least part of the side chains have the moiety represented by general formula (IV).
• R 1 and R 2 are each independently a hydrogen atom, a methyl group or an ethyl group; R 3 is a hydrogen atom or a methyl group; one of R 4 and R 5 is a methyl group or an ethyl group; is a hydrogen atom.
• m and n represent the number of repeating units, and are integers of 1 ⁇ m ⁇ 30 and 1 ⁇ n ⁇ 70.
• Still another embodiment of the modified vinyl alcohol polymer according to the present invention has a monomer unit represented by general formula (V). (Wherein, R 1 , R 2 , R 3 , R 4 , R 5 , n and m are as defined in general formula (IV).)
• the viscosity average degree of polymerization is 100 to 5000 and the degree of saponification is 65 mol% to 90 mol%.
• Another aspect of the present invention is a dispersion stabilizer for suspension polymerization containing the modified vinyl alcohol polymer according to the present invention.
• the dispersion stabilizer for suspension polymerization according to the present invention is used to combine a vinyl compound monomer, or a vinyl compound monomer and a monomer copolymerizable therewith.
• a method for producing a vinyl resin comprising dispersing a mixture in water and carrying out suspension polymerization.
• a method for producing a modified vinyl alcohol polymer according to the present invention wherein a vinyl ester monomer and , an unsaturated monomer having a polyoxyalkylene unit represented by the general formula (I) and an unsaturated monomer deriving a dicarboxylic acid unit represented by the general formula (III) are copolymerized to obtain a modified vinyl ester polymer. and a step of saponifying the resulting modified vinyl ester-based polymer.
• the unsaturated monomer having a polyoxyalkylene unit represented by general formula (I) is a polyoxyalkylene represented by general formula (VI).
• R 1 and R 2 are each independently a hydrogen atom, a methyl group or an ethyl group;
• R 3 is a hydrogen atom or a methyl group;
• one of R 4 and R 5 is a methyl group or an ethyl group; is a hydrogen atom.
• m and n represent the number of repeating units, and are integers of 1 ⁇ m ⁇ 30 and 1 ⁇ n ⁇ 70.
• the resin particles are stably formed under a wide range of stirring conditions with little formation of coarse particles and have a highly uniform particle size. is obtained.
• the modified vinyl alcohol polymer of the present invention has a main chain having a polyvinyl alcohol chain and side chains bonded to the main chain, and the side chains are polyoxyalkylene represented by general formula (I). have units.
• R 1 and R 2 are each independently a hydrogen atom, a methyl group or an ethyl group
• R 3 is a hydrogen atom or a methyl group
• n represents the number of repeating units, and is an integer of 1 ⁇ n ⁇ 70 .
• the lower limit of n is preferably 10 or more, more preferably 15 or more. Moreover, the upper limit of n is preferably 65 or less, more preferably 60 or less.
• At least part of the side chains preferably has two or more different oxyalkylene moieties as shown in general formula (IV). More preferably, all of the side chains having polyoxyalkylene units represented by general formula (I) have two or more different oxyalkylene moieties as represented by general formula (IV).
• compounds having two or more different oxyalkylene moieties as shown in general formula (IV) include butylene oxide (one of R 4 or R 5 is an ethyl group and the other is an hydrogen atom), and the portion with n repeating units is ethylene oxide (both R 1 and R 2 are hydrogen atoms), or the portion with m repeating units is propylene oxide (one of R 4 or R 5 is a methyl group , the other is a hydrogen atom), and the portion having n repeating units is ethylene oxide (both R 1 and R 2 are hydrogen atoms).
• the portion having m repeating units is butylene oxide (one of R 4 or R 5 is an ethyl group and the other is a hydrogen atom), and the portion having n repeating units is ethylene oxide (both R 1 and R 2 are hydrogen atoms).
• the portion having the number of repeating units of m and the portion having the number of repeating units of n may be in the form of either random or block arrangement, but the physical properties based on the alkylene modifying group are more favorable. A block-like arrangement is preferable from the viewpoint of facilitating expression.
• R 1 and R 2 are each independently a hydrogen atom, a methyl group or an ethyl group; R 3 is a hydrogen atom or a methyl group; one of R 4 and R 5 is a methyl group or an ethyl group; is a hydrogen atom.
• m and n represent the number of repeating units, and are integers of 1 ⁇ m ⁇ 30 and 1 ⁇ n ⁇ 70.
• the lower limit of m is preferably 3 or more, more preferably 5 or more. Moreover, the upper limit of m is preferably 25 or less, more preferably 20 or less.
• the lower limit of n is preferably 10 or more, more preferably 15 or more. Moreover, the upper limit of n is preferably 65 or less, more preferably 60 or less.
• the structure of the connecting portion between the side chain and the main chain in the modified vinyl alcohol polymer is not particularly limited. Since it can be cleaved during the process of saponification of the polymer, it preferably does not have a structure that is easily hydrolyzed. Specifically, it is preferably connected by an ether bond or a carbon-carbon bond.
• Examples of unsaturated monomers that induce side chains (modified structures) having polyoxyalkylene units represented by formula (I) include polyoxyalkylene alkenyl ethers, polyoxyalkylene mono(meth)acrylamides, polyoxyalkylene mono( meth)allyl ether, polyoxyalkylene monovinyl ether, polyoxyalkylene mono (meth) acrylate, specifically polyoxybutylene polyoxyethylene monoacrylamide, polyoxypropylene polyoxyethylene monoacrylamide, polyoxybutylene mono Acrylamide, polyoxybutylene polyoxypropylene monoacrylamide, polyoxypropylene monoacrylamide, polyoxypropyleneoxyethylene monoacrylamide, polyoxybutylene polyoxyethylene monomethacrylamide, polyoxypropylene polyoxyethylene monomethacrylamide, polyoxybutylene monomethacrylamide Amide, polyoxybutylene polyoxypropylene monomethacrylamide, polyoxypropylene monomethacrylamide, polyoxypropyleneoxyethylene monomethacrylamide, polyoxybutylene mono
• unsaturated monomers having two or more different repeating units represented by general formula (IV) are preferable from the viewpoint of performance
• polyoxyalkylene alkenyl ethers represented by general formula (VI), especially , and polyoxybutylene polyoxyethylene alkenyl ether (one of R 4 or R 5 is an ethyl group and the other is a hydrogen atom, and both R 1 and R 2 are hydrogen atoms) are more preferably used in terms of reactivity and performance. be done.
• R 1 , R 2 , R 3 , R 4 , R 5 , m and n are as defined in general formula (IV) above.
• the modified vinyl alcohol polymer of the present invention has a carbonyl unit represented by general formula (II) at the main chain end.
• A represents a hydrogen atom or an alkyl group having 1 to 9 carbon atoms.
• a at the carbonyl end is an alkyl group having 1 to 9 carbon atoms or a hydrogen atom.
• the method of inducing a terminal in which A is an alkyl group having 1 to 9 carbon atoms as in the general formula (II) is not particularly limited, but when radically polymerizing a vinyl ester monomer, polymerization is carried out in the presence of the corresponding aldehyde.
• a simple method is to dissolve the obtained polymer in an alcohol and then treat it with an alkali such as sodium hydroxide or ammonia or an acid such as hydrochloric acid or p-toluenesulfonic acid to saponify the vinyl ester polymer. Efficient.
• the number of carbon atoms in A exceeds 9, the amount of unsaturated double bonds generated due to the carbonyl terminal is reduced, resulting in a modified vinyl alcohol polymer with poor dispersibility, and the required physical properties are not sufficiently exhibited. Therefore, the number of carbon atoms in A is preferably 9 or less, more preferably 8 or less, even more preferably 6 or less, and even more preferably 5 or less. A may be linear or branched.
• preferable A examples include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, isopentyl group and neopentyl group. , t-pentyl group, hexyl group, isohexyl group, heptyl group, octyl group and the like, and a methyl group is particularly preferred.
• the modified vinyl alcohol polymer of the present invention has a dicarboxylic acid unit represented by general formula (III) in the main chain.
• X and Y each independently represent an alkyl group having 1 to 12 carbon atoms, a hydrogen atom or a metal atom.
• the number of carbon atoms in X and Y is preferably 12 or less, more preferably 8 or less, even more preferably 4 or less, and 2 or less in terms of ease of recovery during production. is even more preferred.
• X may be linear or branched.
• Specific examples of preferable X and Y include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, isopentyl group, A neopentyl group, a t-pentyl group, a hexyl group, an isohexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, and the like are mentioned. , methyl groups are particularly preferred.
• the unsaturated monomer from which the dicarboxylic acid unit represented by the general formula (III) is derived is not particularly limited, but dimethyl maleate, monomethyl maleate, diethyl maleate, monoethyl maleate, dipropyl maleate, malein monopropyl acid, dibutyl maleate, monobutyl maleate, dipentyl maleate, monopentyl maleate, dihexyl maleate, monohexyl maleate, dioctyl maleate, monooctyl maleate, dimethyl fumarate, monomethyl fumarate, diethyl fumarate, monoethyl fumarate, dibutyl fumarate, monobutyl fumarate, dipentyl fumarate, monopentyl fumarate, dihexyl fumarate, monohexyl fumarate, diheptyl fumarate, monoheptyl fumarate, dioctyl fumarate, monooctyl fumarate,
• the modified vinyl alcohol polymer of the present invention has polyoxyalkylene units represented by the general formula (I) in side chains with respect to the total number of moles of the monomer units constituting the main chain of the modified vinyl alcohol polymer.
• the ratio of the number of moles of monomer units is preferably 0.01 mol % to 5.0 mol %.
• the upper limit of the ratio of the number of moles of monomer units having polyoxyalkylene units in side chains is preferably 5.0 mol % or less, more preferably 3.0 mol % or less. It is even more preferably 0 mol % or less, and even more preferably 0.5 mol % or less.
• the lower limit of the ratio of the number of moles of monomer units having polyoxyalkylene units in side chains is preferably 0.01 mol % or more, more preferably 0.03 mol % or more, and 0.01 mol % or more. 05 mol % or more is even more preferred, and 0.1 mol % or more is even more preferred.
• the ratio of the number of moles of monomer units having a polyoxyalkylene unit in the side chain represented by general formula (I) to the total number of moles of monomer units constituting the main chain of the modified vinyl alcohol polymer is 1H .
• - can be determined by NMR.
• a modified vinyl alcohol polymer is saponified to a degree of saponification of 99.95 mol % or more, and then thoroughly washed with methanol to prepare a modified vinyl alcohol polymer for analysis.
• the prepared modified vinyl alcohol polymer for analysis is dissolved in heavy water, and a few drops of NaOH heavy aqueous solution are added to adjust the pH to 14. Then, the pH is measured at 80° C. using 1 H-NMR.
• the oxypropylene part or the oxybutylene part is higher than the ratio of the number of moles calculated from the oxyethylene part. Since the ratio of the number of moles calculated based on the integrated value of the peak attributed to the terminal methyl group of is higher in measurement accuracy, if there is a difference between the two values, the terminal of the oxypropylene part or the oxybutylene part The ratio of the number of moles calculated based on the integrated value of the peak attributed to the methyl group is adopted.
• the ratio of the number of moles of the carbonyl unit represented by the general formula (II) to the total number of moles of the monomer units constituting the main chain of the modified vinyl alcohol polymer is 0. It is preferably from 0.01 mol % to 1.0 mol %.
• the ratio of the number of moles of carbonyl units is preferably 0.8 mol% or less, more preferably 0.5 mol% or less, even more preferably 0.3 mol% or less, and 0 0.25 mol % or less is even more preferred.
• the ratio of the number of moles of carbonyl units is preferably 0.02 mol % or more, more preferably 0.05 mol % or more, and even more preferably 0.1 mol % or more.
• the ratio of the number of moles of the carbonyl unit represented by general formula (II) to the total number of moles of the monomer units constituting the main chain of the modified vinyl alcohol polymer can be determined by 1 H-NMR.
• a modified vinyl alcohol polymer is saponified to a degree of saponification of 99.95 mol % or more, and then thoroughly washed with methanol to prepare a modified vinyl alcohol polymer for analysis.
• the prepared modified vinyl alcohol polymer for analysis is dissolved in heavy water, and several drops of NaOH heavy aqueous solution are added to adjust the pH to 14. Then, measurement is performed at 80° C. to obtain a 1 H-NMR spectrum.
• saponification is not necessary, and the analysis is performed as it is.
• the integrated value of the peak of the methylene group (1.2 to 1.8 ppm) of the main chain of the modified vinyl alcohol polymer it is calculated from the integrated value of the peak indicating the carbonyl end.
• A is a methyl group
• the peak is 0.95 to 1.10 ppm, which is the terminal methyl group.
• the formyl group is calculated from the integrated value of the peak at 9.2 to 9.8 ppm.
• the ratio of the number of moles of the dicarboxylic acid unit represented by the general formula (III) to the total number of moles of the monomer units constituting the main chain of the modified vinyl alcohol polymer is It is preferably 0.01 mol % to 0.5 mol %.
• the upper limit of the ratio of the number of moles of dicarboxylic acid units is preferably 0.5 mol% or less, more preferably 0.4 mol% or less, and even more preferably 0.35 mol% or less. Preferably, it is still more preferably 0.3 mol % or less.
• the ratio of the number of moles of the dicarboxylic acid unit represented by the general formula (III) is less than 0.01 mol%, the number of unsaturated double bond starting points caused by the dicarboxylic acid is reduced and the protective colloid property is lowered. As a result, a vinyl resin having an appropriate particle size may not be obtained. Therefore, the ratio of the number of moles of dicarboxylic acid units is preferably 0.02 mol % or more, more preferably 0.03 mol % or more.
• the ratio of the number of moles of the dicarboxylic acid unit represented by general formula (III) to the number of moles of all the monomer units constituting the main chain of the modified vinyl alcohol polymer can be determined by 13 C-NMR.
• a modified vinyl alcohol polymer is saponified to a degree of saponification of 99.95 mol % or more, and then thoroughly washed with methanol to prepare a modified vinyl alcohol polymer for analysis.
• the prepared modified vinyl alcohol polymer for analysis is dissolved in heavy water, and several drops of NaOH heavy aqueous solution are added to adjust the pH to 14. Then, the solution is measured at 80° C. to obtain a 13 C-NMR spectrum.
• the lower limit of the viscosity-average degree of polymerization of the modified vinyl alcohol polymer of the present invention is preferably 100 or more, more preferably 200 or more, in order to increase the dispersion stability during suspension polymerization of the vinyl compound. Preferably, it is even more preferably 300 or more.
• the upper limit of the viscosity average degree of polymerization of the modified vinyl alcohol polymer is preferably 5000 or less, more preferably 3000 or less, in order to prevent handling from becoming difficult due to an increase in the viscosity of the aqueous solution. It is even more preferably 2000 or less, and even more preferably 1500 or less.
• the viscosity average degree of polymerization of the modified vinyl alcohol polymer is measured according to JIS K6726:1994. That is, it is obtained from the intrinsic viscosity [ ⁇ ] measured in water at 30° C. after completely saponifying and purifying the modified vinyl alcohol polymer.
• the lower limit of the degree of saponification of the modified vinyl alcohol polymer of the present invention is preferably 65 mol% or more, more preferably 67 mol% or more, more preferably 70 mol% or more, in order to increase water solubility and facilitate handling. Even more preferably mol % or more.
• the upper limit of the degree of saponification of the modified vinyl alcohol polymer is 90 mol % or less in order to increase the porosity of the particles obtained when the vinyl compound is subjected to suspension polymerization to increase the absorbability of the plasticizer. It is preferably 85 mol % or less, and even more preferably 80 mol % or less.
• the degree of saponification of the modified vinyl alcohol polymer is measured according to JIS K6726:1994. That is, it can be obtained by quantifying the remaining acetic acid group (mol%) in the sample with sodium hydroxide and subtracting it from 100.
• the method for producing a modified vinyl alcohol polymer according to the present invention is not particularly limited, but in one embodiment of the method for producing a modified vinyl alcohol polymer according to the present invention, an aldehyde having a carbonyl unit represented by general formula (II) in the presence of a vinyl ester monomer represented by vinyl acetate, an unsaturated monomer having a polyoxyalkylene unit represented by general formula (I), and a dicarboxylic acid unit represented by general formula (III).
• a production method comprising a step of copolymerizing an unsaturated monomer to be induced to obtain a modified vinyl ester polymer and a step of saponifying the obtained modified vinyl ester polymer is easy and economical, and is preferred.
• used for Vinyl ester monomers include vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate and vinyl versatate. is mentioned.
• monomers copolymerizable with vinyl ester monomers such as unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid, or alkyl esters of these unsaturated monocarboxylic acids, fumaric acid, itacones
• unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid
• alkyl esters of these unsaturated monocarboxylic acids fumaric acid
• Unsaturated dicarboxylic acids such as acids or alkyl esters of these unsaturated dicarboxylic acids, nitriles or amides such as acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, olefin sulfonic acids such as ethylenesulfonic acid, allylsulfonic acid, methallylsulfonic acid
• salts thereof vinyl ethers, vinyl ketones, ⁇ -olefins, vinyl halides, vinyli
• the mixing ratio of the copolymerizable monomers is appropriately 10 mol % or less in total, preferably 5 mol % or less in total, based on the number of moles of the vinyl ester monomer.
• any of batch polymerization, semi-batch polymerization, continuous polymerization, and semi-continuous polymerization may be used as the polymerization method for producing the modified vinyl ester polymer of the present invention.
• the polymerization method any method can be adopted from known methods such as bulk polymerization method, solution polymerization method, suspension polymerization method and emulsion polymerization method.
• a solution polymerization method in which polymerization is performed in the presence of an alcoholic solvent or a bulk polymerization method in which polymerization is performed without using a solvent is preferable, instead of a suspension polymerization method and an emulsion polymerization method that require control of the polymer particle size.
• Methanol, ethanol, isopropanol and the like can be used as the alcoholic solvent used in the solution polymerization method, but the solvent is not limited to these. These solvents may be used alone, or two or more of them may be used in combination.
• the polymerization temperature for obtaining the modified vinyl ester polymer of the present invention is not particularly limited, it is preferably 0°C or higher and 200°C or lower, more preferably 30°C or higher and 150°C or lower. If the temperature for copolymerization is lower than 0°C, it is not preferable because a sufficient polymerization rate cannot be obtained. Further, when the polymerization temperature is higher than 200° C., it is difficult to obtain the desired modified vinyl alcohol polymer.
• a method for controlling the temperature to be 0° C. or more and 200° C. or less, which is adopted when carrying out copolymerization there is a method of controlling with an external jacket using a suitable heat medium such as water.
• the polymerization initiator used when polymerizing the modified vinyl ester polymer of the present invention is not particularly limited, but azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobis(4- methoxy-2,4-dimethylvaleronitrile), azo compounds such as azobisdimethylvaleronitrile, azobismethoxyvaleronitrile, acetyl peroxide, benzoyl peroxide, lauroyl peroxide, acetylcyclohexylsulfonyl peroxide, 2,4,4 -Peroxides such as trimethylpentyl-2-peroxyphenoxyacetate, peroxydicarbonate compounds such as diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, diethoxyethyl peroxydicarbonate, t-butyl peroxy Perester compounds such as neodecanoate
• an antioxidant such as citric acid may be added to the polymerization system in an amount of 1 ppm or more and 100 ppm or less (based on the weight of the vinyl ester monomer).
• the unsaturated monomer that induces the dicarboxylic acid unit represented by the general formula (III) is intermittently added in the course of the copolymerization.
• continuous addition is preferred.
• a modified vinyl alcohol-based polymer is produced from a modified vinyl ester-based polymer having a narrow composition distribution, and is used as a dispersion stabilizer for suspension polymerization to produce vinyl. Suspension polymerization of the system compound is considered to contribute to refinement of resin particles and reduction of coarse particles.
• an unsaturated monomer deriving a dicarboxylic acid monomer represented by the general formula (III) is first added to the reaction vessel in an amount of 1 to 30% by mass, preferably 5 to 20% by mass of the total added amount. It is more preferable to add the rest of the unsaturated monomer intermittently or continuously from the initial stage of the polymerization (the stage where the polymerization rate is 0 to 1% with respect to the final polymerization rate). The intermittent or continuous addition of the unsaturated monomer is preferably continued until the polymerization rate reaches 60% or more with respect to the final polymerization rate, and the polymerization rate is 80% or more with respect to the final polymerization rate.
• the polymerization rate measure 5.0 g of the polymerization liquid, dry it at 150° C. for 30 minutes, and determine the concentration of the polymerization liquid from the mass of the dry matter after volatilization of unreacted monomers and solvent. The mass of the polymer polymerized at that time is calculated, and the rate of polymerization is calculated from the ratio of the polymer to the total charged amount of the monomers.
• the saponification method for producing the modified vinyl alcohol polymer according to the present invention is not particularly limited. It is preferable to use in Alcohols include methanol, ethanol, butanol, and the like.
• the concentration of the modified vinyl ester polymer in alcohol can be selected from the range of 20 to 70 mass %.
• Alkali catalysts such as hydroxides and alcoholates of alkali metals such as sodium hydroxide, potassium hydroxide, sodium methylate, sodium ethylate and potassium methylate can be used as alkali catalysts, and acid catalysts such as hydrochloric acid, An aqueous inorganic acid solution such as sulfuric acid, and an organic acid such as p-toluenesulfonic acid can be used.
• the amount of these catalysts used is preferably 1 to 100 millimol equivalents relative to the vinyl ester monomer.
• the saponification temperature is not particularly limited, it is usually in the range of 10 to 70°C, preferably in the range of 30 to 50°C.
• the reaction is usually carried out over 0.5-3 hours.
• the drying conditions for producing the modified vinyl alcohol polymer according to the present invention are not particularly limited, but from the viewpoint of introducing double bonds resulting from carbonyl groups and dicarboxylic acid groups, drying at 90° C. or higher is preferable. It is preferable to carry out drying while heating for 1 hour or longer, more preferably 100° C. or higher for 1 hour or longer, and even more preferably 120° C. or higher for 2 hours or longer. Although no particular upper limit is set for the heating temperature during drying, from the viewpoint of preventing gelation, drying is preferably performed at 180°C or less, more preferably 160°C or less, and even more preferably 150°C or less. is desirable. Therefore, the heating conditions for the drying step are preferably, for example, 90 to 180° C. for 1 to 5 hours, more preferably 100 to 160° C. for 1 to 5 hours.
• the dispersion stabilizer for suspension polymerization of the present invention may be the modified vinyl alcohol polymer of the present invention alone.
• An alcohol-based polymer and other various additives may be contained.
• additives include polymerization modifiers such as aldehydes, halogenated hydrocarbons and mercaptans; polymerization inhibitors such as phenol compounds, sulfur compounds and N-oxide compounds; pH adjusters; cross-linking agents; antifungal agents, antiblocking agents; antifoaming agents and the like.
• the dispersion stabilizer for suspension polymerization of the present invention preferably contains the modified vinyl alcohol polymer of the present invention in an amount of 10% by mass or more, preferably 30% by mass or more. is more preferable, and it is even more preferable to contain 70% by mass or more.
• the dispersion stabilizer for suspension polymerization of the present invention can be suitably used particularly for suspension polymerization of vinyl compounds. Therefore, according to another aspect of the present invention, a vinyl compound monomer or a mixture of a vinyl compound monomer and a monomer copolymerizable therewith using a dispersion stabilizer for suspension polymerization is dispersed in water to carry out suspension polymerization.
• Vinyl compounds include vinyl halides such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; acrylic acid, methacrylic acid, esters and salts thereof; maleic acid, fumaric acid, esters and anhydrides thereof; Styrene, acrylonitrile, vinylidene chloride, vinyl ether and the like.
• the dispersion stabilizer for suspension polymerization according to one embodiment of the present invention is particularly suitably suspended with vinyl chloride alone or with a monomer capable of copolymerizing vinyl chloride with vinyl chloride. Used for turbidity polymerization.
• Examples of monomers that can be copolymerized with vinyl chloride include vinyl esters such as vinyl acetate and vinyl propionate; (meth)acrylate esters such as methyl (meth)acrylate and ethyl (meth)acrylate; ethylene, ⁇ -olefins such as propylene; unsaturated dicarboxylic acids such as maleic anhydride and itaconic acid; acrylonitrile, styrene, vinylidene chloride, vinyl ether and the like.
• the dispersion stabilizer for suspension polymerization of the present invention can be used alone or in combination with other stabilizers such as cellulose derivatives and surfactants.
• the dispersion stabilizer for suspension polymerization of the present invention By using the dispersion stabilizer for suspension polymerization of the present invention, it is possible to stably obtain a vinyl chloride resin that is fine, has a uniform particle size distribution, and has excellent physical properties under a wide range of stirring conditions.
• the polymerization method of the vinyl compound will be specifically described with examples, but the method is not limited to these.
• the dispersion stabilizer for suspension polymerization described above is added in an amount of 0.01% by mass to 0.3% by mass, preferably 0.3% by mass, based on the vinyl compound monomer. 0.04% by mass to 0.15% by mass is added.
• the polymerization initiator may be one conventionally used for the polymerization of vinyl compounds, including peroxydicarbonate such as diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, diethoxyethyl peroxydicarbonate.
• peroxydicarbonate such as diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, diethoxyethyl peroxydicarbonate.
• perester compounds such as t-butyl peroxyneodecanoate and ⁇ -cumyl peroxyneodecanoate, acetylcyclohexylsulfonyl peroxide, 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate Peroxides, azo compounds such as azobis-2,4-dimethylvaleronitrile and azobis(4-methoxy-2,4-dimethylvaleronitrile), potassium persulfate, ammonium persulfate, hydrogen peroxide, etc. alone or in combination can be used
• polymerization modifiers chain transfer agents, gelation modifiers, antistatic agents, pH adjusters, etc. that are appropriately used in the polymerization of vinyl compounds.
• the charging ratio of each component, the polymerization temperature, etc. in carrying out the polymerization of the vinyl compound may be determined according to the conditions conventionally used in the suspension polymerization of the vinyl compound, and there is no particular reason for limitation.
• Example 1 Vinyl acetate 2000 g, methanol 100 g, acetaldehyde 64 g, dimethyl maleate 0.04 g, azobisisobutyronitrile 0.25 g, poly 45 g of oxyalkylene alkenyl ether (commercially available, hereinafter referred to as "monomer A". A portion having m repeating units and a portion having n repeating units are arranged in a block-like manner.) into a polymerization vessel. After charging, the inside of the system was replaced with nitrogen for 30 minutes, and the temperature was started to rise.
• monomer A oxyalkylene alkenyl ether
• ⁇ Condition (2) Suspension polymerization of vinyl chloride, stirring with small shear>
• 10 kg of water at 30 ° C. is stirred, 5.6 g of the modified vinyl alcohol polymer produced above as a dispersion stabilizer, and t-butyl peroxy neodeca as a polymerization initiator.
• 4.6 g of noate and 1 g of ⁇ -cumyl peroxyneodecanoate were charged.
• 7 kg of vinyl chloride monomer was added and polymerized for 4 hours at a polymerization temperature of 53° C. and a stirrer rotation speed of 500 rpm.
• the number of rotations of the stirring blade was set to be low, and when a dispersant having a low dispersing power was used, the particles of the vinyl chloride resin were set to tend to be coarse.
• the average particle size was measured in accordance with JIS Z8815: 1994, 60 mesh (250 ⁇ m opening), 80 mesh (180 ⁇ m opening), 100 mesh (150 ⁇ m opening), 150 mesh (106 ⁇ m opening), 200 mesh ( Using a sieve with an opening of 75 ⁇ m), the average particle diameter (D50) at a cumulative frequency of 50% (based on mass) and the mass ratio of particles of 250 ⁇ m or more were determined. Table 1 shows the results.
• Example 2 2,000 g of vinyl acetate, 100 g of methanol, 24 g of acetaldehyde, 0.08 g of dimethyl maleate, 0.25 g of azobisisobutyronitrile, and 73 g of monomer A were charged into a polymerization vessel, the system was replaced with nitrogen for 30 minutes, and the temperature was started to rise. did. When the liquid temperature reached 60° C., continuous addition of dimethyl maleate and methanol was started and continued until the final polymerization rate reached 80% or more. Specifically, polymerization was carried out while continuously adding 0.72 g of dimethyl maleate and 50 g of methanol at a uniform addition rate over 8 hours.
• Example 1 After 9 hours had passed since the liquid temperature reached 60°C, the polymerization was terminated by cooling. Thereafter, a modified vinyl alcohol polymer was produced according to Example 1, and the viscosity average degree of polymerization, saponification degree and modification rate were measured in the same manner as in Example 1. Suspension polymerization of vinyl chloride was carried out under the same conditions as in Example 1, except that the obtained modified vinyl alcohol polymer was used, and evaluation was carried out. Table 1 shows the results.
• Example 3 2,000 g of vinyl acetate, 100 g of methanol, 33 g of acetaldehyde, 0.24 g of dimethyl maleate, 0.25 g of azobisisobutyronitrile, and 123 g of monomer A were charged into a polymerization vessel, the system was replaced with nitrogen for 30 minutes, and the temperature was started to rise. did. When the liquid temperature reached 60° C., continuous addition of dimethyl maleate and methanol was started and continued until the final polymerization rate reached 80% or more. Specifically, polymerization was carried out while continuously adding 2.16 g of dimethyl maleate and 50 g of methanol at a uniform addition rate over 8 hours.
• Example 1 After 9 hours had passed since the liquid temperature reached 60°C, the polymerization was terminated by cooling. Thereafter, a modified vinyl alcohol polymer was produced according to Example 1, and the viscosity average degree of polymerization, saponification degree and modification rate were measured in the same manner as in Example 1. Suspension polymerization of vinyl chloride was carried out under the same conditions as in Example 1, except that the obtained modified vinyl alcohol polymer was used, and evaluation was carried out. Table 1 shows the results.
• Example 4 Vinyl acetate 2000 g, methanol 100 g, acetaldehyde 53 g, dimethyl maleate 0.40 g, azobisisobutyronitrile 0.25 g, poly 138 g of oxyalkylene alkenyl ether (commercially available, hereinafter referred to as "monomer B".
• Example 5 2000 g of vinyl acetate, 100 g of methanol, 10 g of acetaldehyde, 0.72 g of dimethyl maleate, 0.25 g of azobisisobutyronitrile, and 159 g of monomer B were charged into a polymerization vessel, the system was replaced with nitrogen for 30 minutes, and the temperature was started to rise. did. When the liquid temperature reached 60° C., continuous addition of dimethyl maleate and methanol was started and continued until the final polymerization rate reached 80% or more. Specifically, polymerization was carried out while continuously adding 6.48 g of dimethyl maleate and 50 g of methanol at a uniform addition rate over 8 hours.
• Example 1 After 9 hours had passed since the liquid temperature reached 60°C, the polymerization was terminated by cooling. Thereafter, a modified vinyl alcohol polymer was produced according to Example 1, and the viscosity average degree of polymerization, saponification degree and modification rate were measured in the same manner as in Example 1. Suspension polymerization of vinyl chloride was carried out under the same conditions as in Example 1, except that the obtained modified vinyl alcohol polymer was used, and evaluation was carried out. Table 1 shows the results.
• Example 6 2,000 g of vinyl acetate, 100 g of methanol, 74 g of acetaldehyde, 0.90 g of dimethyl maleate, 0.25 g of azobisisobutyronitrile, and 240 g of monomer B were charged into a polymerization vessel, the inside of the system was replaced with nitrogen for 30 minutes, and the temperature was started to rise. did. When the liquid temperature reached 60° C., continuous addition of dimethyl maleate and methanol was started and continued until the final polymerization rate reached 80% or more. Specifically, polymerization was carried out while continuously adding 8.10 g of dimethyl maleate and 50 g of methanol at a uniform addition rate over 8 hours.
• Example 1 After 9 hours had passed since the liquid temperature reached 60°C, the polymerization was terminated by cooling. Thereafter, a modified vinyl alcohol polymer was produced according to Example 1, and the viscosity average degree of polymerization, saponification degree and modification rate were measured in the same manner as in Example 1. Suspension polymerization of vinyl chloride was carried out under the same conditions as in Example 1, except that the obtained modified vinyl alcohol polymer was used, and evaluation was carried out. Table 1 shows the results.
• Example 7 2000 g of vinyl acetate, 100 g of methanol, 20 g of formaldehyde, 0.40 g of dimethyl maleate, 0.25 g of azobisisobutyronitrile, and 168 g of monomer A were charged into a polymerization vessel, the system was replaced with nitrogen for 30 minutes, and the temperature was started to rise. did. When the liquid temperature reached 60° C., continuous addition of dimethyl maleate and methanol was started and continued until the final polymerization rate reached 80% or more. Specifically, polymerization was carried out while continuously adding 3.60 g of dimethyl maleate and 50 g of methanol at a uniform addition rate over 8 hours.
• Example 1 After 9 hours had passed since the liquid temperature reached 60°C, the polymerization was terminated by cooling. Thereafter, a modified vinyl alcohol polymer was produced according to Example 1, and the viscosity average degree of polymerization, saponification degree and modification rate were measured in the same manner as in Example 1. Suspension polymerization of vinyl chloride was carried out under the same conditions as in Example 1, except that the obtained modified vinyl alcohol polymer was used, and evaluation was carried out. Table 1 shows the results.
• Example 8 2000 g of vinyl acetate, 100 g of methanol, 142 g of n-butyraldehyde, 0.40 g of dimethyl maleate, 0.25 g of azobisisobutyronitrile, and 168 g of monomer A are placed in a polymerization vessel, the inside of the system is replaced with nitrogen for 30 minutes, and the temperature is raised. started. When the liquid temperature reached 60° C., continuous addition of dimethyl maleate and methanol was started and continued until the final polymerization rate reached 80% or more. Specifically, polymerization was carried out while continuously adding 3.60 g of dimethyl maleate and 50 g of methanol at a uniform addition rate over 8 hours.
• Example 1 After 9 hours had passed since the liquid temperature reached 60°C, the polymerization was terminated by cooling. Thereafter, a modified vinyl alcohol polymer was produced according to Example 1, and the viscosity average degree of polymerization, saponification degree and modification rate were measured in the same manner as in Example 1. Suspension polymerization of vinyl chloride was carried out under the same conditions as in Example 1, except that the obtained modified vinyl alcohol polymer was used, and evaluation was carried out. Table 1 shows the results.
• Example 9 2,000 g of vinyl acetate, 100 g of methanol, 25 g of acetaldehyde, 0.48 g of diethyl maleate, 0.25 g of azobisisobutyronitrile, and 106 g of monomer A were charged into a polymerization vessel, the system was replaced with nitrogen for 30 minutes, and the temperature was started to rise. did. When the liquid temperature reached 60° C., continuous addition of diethyl maleate and methanol was started and continued until the final polymerization rate reached 80% or more. Specifically, polymerization was carried out while continuously adding 4.32 g of diethyl maleate and 50 g of methanol at a uniform addition rate over 8 hours.
• Example 1 After 9 hours had passed since the liquid temperature reached 60°C, the polymerization was terminated by cooling. Thereafter, a modified vinyl alcohol polymer was produced according to Example 1, and the viscosity average degree of polymerization, saponification degree and modification rate were measured in the same manner as in Example 1. Suspension polymerization of vinyl chloride was carried out under the same conditions as in Example 1, except that the obtained modified vinyl alcohol polymer was used, and evaluation was carried out. Table 1 shows the results.
• the portion with the number of repeating units m and the portion with the number of repeating units n are random 52 g was placed in a polymerization vessel, the inside of the system was replaced with nitrogen for 30 minutes, and the temperature was started to rise.
• Example 2 Thereafter, a modified vinyl alcohol polymer was produced according to Example 1, and the viscosity average degree of polymerization, saponification degree and modification rate were measured in the same manner as in Example 1. Suspension polymerization of vinyl chloride was carried out under the same conditions as in Example 1, except that the obtained modified vinyl alcohol polymer was used, and evaluation was carried out. Table 2 shows the results.
• Example 2 Thereafter, a modified vinyl alcohol polymer was produced according to Example 1, and the viscosity average degree of polymerization, saponification degree and modification rate were measured in the same manner as in Example 1. Suspension polymerization of vinyl chloride was carried out under the same conditions as in Example 1, except that the obtained modified vinyl alcohol polymer was used, and evaluation was carried out. Table 2 shows the results.
• Example 2 shows the results.
• polymerization was carried out while continuously adding 8.1 g of dimethyl maleate and 50 g of methanol at a uniform addition rate over 8 hours. After 9 hours had passed since the liquid temperature reached 60°C, the polymerization was terminated by cooling. Thereafter, a modified vinyl alcohol polymer was produced according to Example 1, and the viscosity average degree of polymerization, saponification degree and modification rate were measured in the same manner as in Example 1. 1 H-NMR of the resulting modified vinyl alcohol polymer was measured, but the peaks derived from modified species observed in polyvinyl acetate were not observed in polyvinyl alcohol.
• the modified vinyl alcohol polymer shown in Comparative Examples 1 to 7 When the modified vinyl alcohol polymer shown in Comparative Examples 1 to 7 is used as a dispersion stabilizer, the vinyl chloride resin particles may become enlarged and the amount of coarse particles may increase depending on the stirring speed of the vinyl chloride, resulting in dispersion stability. The scope of application as a drug was narrow. In contrast, when the modified vinyl alcohol polymers shown in Examples 1 to 11 were used as the dispersion stabilizer, the uniformity of the particle size of the vinyl chloride resin was maintained even when the stirring speed during polymerization of the vinyl chloride was changed. was high and the formation of coarse particles was low. Therefore, the modified vinyl alcohol polymers according to Examples 1 to 11 have high versatility and are industrially extremely advantageous.

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