Classifications

• • 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
  • C08F26/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a single or double bond to nitrogen or by a heterocyclic ring containing nitrogen
  • C08F26/02—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a single or double bond to nitrogen or by a heterocyclic ring containing nitrogen by a single or double bond to nitrogen
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C231/00—Preparation of carboxylic acid amides
  • C07C231/12—Preparation of carboxylic acid amides by reactions not involving the formation of carboxamide groups
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C233/00—Carboxylic acid amides
  • C07C233/01—Carboxylic acid amides having carbon atoms of carboxamide groups bound to hydrogen atoms or to acyclic carbon atoms
  • C07C233/02—Carboxylic acid amides having carbon atoms of carboxamide groups bound to hydrogen atoms or to acyclic carbon atoms having nitrogen atoms of carboxamide groups bound to hydrogen atoms or to carbon atoms of unsubstituted hydrocarbon radicals
  • C07C233/03—Carboxylic acid amides having carbon atoms of carboxamide groups bound to hydrogen atoms or to acyclic carbon atoms having nitrogen atoms of carboxamide groups bound to hydrogen atoms or to carbon atoms of unsubstituted hydrocarbon radicals with carbon atoms of carboxamide groups bound to hydrogen atoms
• • 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
  • C08F126/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a single or double bond to nitrogen or by a heterocyclic ring containing nitrogen
  • C08F126/02—Homopolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a single or double bond to nitrogen or by a heterocyclic ring containing nitrogen by a single or double bond to nitrogen
• • 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
  • C08F2/32—Polymerisation in water-in-oil emulsions
• • 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
  • C08F2/44—Polymerisation in the presence of compounding ingredients, e.g. plasticisers, dyestuffs, fillers
• • 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
  • C08F226/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a single or double bond to nitrogen or by a heterocyclic ring containing nitrogen
  • C08F226/02—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a single or double bond to nitrogen or by a heterocyclic ring containing nitrogen by a single or double bond to nitrogen
• • 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
  • C08F4/00—Polymerisation catalysts
  • C08F4/04—Azo-compounds
• • 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
  • C08F4/00—Polymerisation catalysts
  • C08F4/28—Oxygen or compounds releasing free oxygen
  • C08F4/32—Organic compounds
  • C08F4/34—Per-compounds with one peroxy-radical
• • 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 method for producing a vinylamine unit-containing polymer, and a polymerization product containing an N-vinylformamide unit-containing polymer which is an intermediate for producing a vinylamine unit-containing polymer.
• Vinylamine unit-containing polymers are widely used for flocculants, papermaking chemicals, fiber treatment agents, and the like.
• Various production methods are known as a method for producing a vinylamine unit-containing polymer.
• a carboxylic acid amide group (—NHC ( ⁇ O ) R (where R is a hydrogen atom, a hydrocarbon group, etc.)) is useful, is relatively easy to hydrolyze, and can be easily derived into a vinylamine unit-containing polymer.
• the method of hydrolyzing the formamide group (—NHC ( ⁇ O) H) of the N-vinylformamide unit-containing polymer is particularly useful (Patent Documents 1 and 2).
• N-vinylformamide which is a raw material for an N-vinylformamide unit-containing polymer.
• a method of thermally decomposing N-methoxyethylformamide to obtain N-vinylformamide Patent Document 3
• a method of obtaining N-vinylformamide by thermally decomposing N-cyanoethylformamide Patent Document 4).
• -Formamide is also mixed in the resulting vinylamine unit-containing polymer.
• the vinylamine unit-containing polymer is used as a papermaking agent, a fiber treatment agent or the like, it is not preferable in terms of quality that formamide is mixed therein.
• formamide has a larger chain transfer constant than water, the molecular weight of an N-vinylformamide unit-containing polymer obtained by polymerizing N-vinylformamide in the presence of formamide is N-vinylformamide in the absence of formamide. It is lower than the N-vinylformamide unit-containing polymer obtained by polymerizing.
• an N-vinylformamide unit-containing polymer is produced using the purified N-vinylformamide. Hydrolysis of the formamide group of the formamide unit-containing polymer produces a vinylamine unit-containing polymer.
• the purification method of crude N-vinylformamide include a distillation method and an extraction method.
• the distillation method has the following problems. Since the boiling point of formamide is close to that of N-vinylformamide, multi-stage precision distillation (fractional distillation) with reflux is required to separate N-vinylformamide and formamide by distillation (Patent Document 5) 6). Multi-stage precision distillation requires complicated and large equipment (such as a rectification column), and therefore, purification by crude N-vinylformamide cannot be easily performed by the distillation method. -N-vinylformamide is unstable compared to other vinylamides, and is particularly thermally unstable, so it must be handled with care. When trying to obtain high purity purified N-vinylformamide by multistage precision distillation with reflux, the yield of N-vinylformamide may decrease due to decomposition or the like.
• the extraction method has the following problems. -Since the equipment for extraction is large and a large amount of solvent is required, the extraction method is not practical.
• the present invention provides a method capable of producing a high-quality vinylamine unit-containing polymer that can suppress a decrease in molecular weight even when a crude N-vinylformamide containing formamide is used, and an intermediate in producing a vinylamine unit-containing polymer. It is an object of the present invention to provide a polymerized product containing an N-vinylformamide unit-containing polymer as a polymer and easily pulverized after drying.
• the present inventors have found that (i) the chain transfer constant of formamide is not so large during the polymerization of N-vinylformamide.
• the effect on the polymerization of vinylformamide is small, and (ii) in the presence of an acid (preferably a strong acid) or a base (preferably a strong base) than the rate of hydrolysis of the formamide group of a polymer containing N-vinylformamide units. Since the hydrolysis rate of formamide is sufficiently high, the present inventors have found that the presence of some formamide has little influence on the hydrolysis of the formamide group of the N-vinylformamide unit-containing polymer.
• this invention has the following aspects. ⁇ 1> A crude N-vinylformamide containing N-vinylformamide and formamide, wherein the content of the formamide is 1 part by mass or more with respect to 100 parts by mass of the N-vinylformamide, A step of preparing a polymerization mixture (a) containing N-vinylformamide, and polymerizing the monomer component in the polymerization mixture (a) to contain a N-vinylformamide unit-containing polymer and formamide A step of obtaining a polymerization product (b) and a step of obtaining a hydrolysis product (c) containing a vinylamine unit-containing polymer by performing a hydrolysis treatment of the polymerization product (b) using an acid or a base.
• a process for producing a vinylamine unit-containing polymer ⁇ 2> Production of vinylamine unit-containing polymer according to ⁇ 1>, wherein the content of formamide in the hydrolysis product (c) is 0.1 parts by mass or less with respect to 100 parts by mass of the vinylamine unit-containing polymer.
• ⁇ 4> When the polymerization product (b) is hydrolyzed, 10 mol% or more of 100 mol% of formamide groups before hydrolysis of the N-vinylformamide unit-containing polymer is hydrolyzed, ⁇ 1 A method for producing a vinylamine unit-containing polymer as defined in any one of> to ⁇ 3>.
• ⁇ 5> Thermal decomposition of crude N-methoxyethylformamide containing N-methoxyethylformamide and formamide to obtain a thermal decomposition product containing N-vinylformamide and formamide, followed by the purification method without refluxing.
• ⁇ 1> to ⁇ 4> further comprising a step of purifying the pyrolysis product to obtain crude N-vinylformamide having a formamide content of 1 part by mass or more with respect to 100 parts by mass of N-vinylformamide.
• a method for producing any vinylamine unit-containing polymer ⁇ 6> The vinylamine according to any one of ⁇ 1> to ⁇ 5>, further comprising a step of drying the polymerization product (b) to form a powder before hydrolyzing the polymerization product (b) A method for producing a unit-containing polymer.
• ⁇ 7> The amount (mol) of formamide contained in the crude N-vinylformamide is less than the amount (mol) of formamide group to be hydrolyzed in the N-vinylformamide unit-containing polymer.
• ⁇ 1> A process for producing a vinylamine unit-containing polymer according to any one of ⁇ 6>.
• ⁇ 8> The vinylamine unit-containing weight according to any one of ⁇ 1> to ⁇ 7>, wherein the content of formamide in the crude N-vinylformamide is 1 to 20 parts by mass with respect to 100 parts by mass of N-vinylformamide Manufacturing method of coalescence.
• ⁇ 9> The method for producing a vinylamine unit-containing polymer according to any one of ⁇ 1> to ⁇ 8>, wherein the polymerization in the step of obtaining the polymerization product (b) is adiabatic polymerization or photopolymerization.
• ⁇ 10> Production of vinylamine unit-containing polymer according to any one of ⁇ 1> to ⁇ 9>, wherein the polymerization in the step of obtaining the polymerization product (b) is adiabatic polymerization and ferrous sulfate is used as a polymerization initiator.
• a polymerization product containing an N-vinylformamide unit-containing polymer and formamide obtained by polymerizing a monomer component containing N-vinylformamide, the content of formamide in the polymerization product Is a polymerization product wherein 1 to 20 parts by mass per 100 parts by mass of the N-vinylformamide unit-containing polymer.
• the polymerization product of the present invention is a polymerization product containing an N-vinylformamide unit-containing polymer, which is an intermediate for producing a vinylamine unit-containing polymer, and is easily pulverized after drying.
• “Monomer” means a compound having an ethylenically unsaturated bond.
• the “unit” in the polymer is a structural unit derived from a monomer formed by polymerizing the monomer, or a part of the structural unit is converted to another structure by processing the polymer.
• “N-vinylformamide unit-containing polymer” means a homopolymer composed of N-vinylformamide units, or a copolymer having an N-vinylformamide unit and other structural units (however, N-vinyl Excluding copolymers having formamide units and vinylamine units).
• the “vinylamine unit-containing polymer” means a homopolymer composed of vinylamine units, or a copolymer having a vinylamine unit and other constituent units.
• the vinylamine unit may be in a salt state.
• “Crude N-methoxyethylformamide” means a mixture comprising N-methoxyethylformamide and formamide.
• the “crude N-vinylformamide” means a mixture containing N-vinylformamide and formamide, and the content of formamide is 1 part by mass or more with respect to 100 parts by mass of N-vinylformamide.
• “Purified N-vinylformamide” is obtained by purifying crude N-vinylformamide, which contains N-vinylformamide free of formamide, or contains N-vinylformamide and formamide, and Is a mixture having a content of less than 1 part by mass with respect to 100 parts by mass of N-vinylformamide.
• the “polymerization mixture (a)” means a mixture containing monomer components prepared using at least a monomer-containing raw material (crude N-vinylformamide or the like).
• the polymerization mixture (a) may contain compounds other than the monomer component (impurities mixed in the monomer-containing raw material, polymerization initiator, solvent, other known additives, etc.).
• the “polymerization product (b)” means a product obtained by polymerizing monomer components in the polymerization mixture (a).
• the polymerization product (b) may contain a compound other than the monomer component contained in the polymerization mixture (a), and the polymerization product (b) obtained immediately after the polymerization of the monomer component. May be dried and powdered, or the powdered polymerization product (b) may be dissolved or dispersed again in water.
• “Hydrolysis product (c)” means a product obtained by subjecting the polymerization product (b) to hydrolysis.
• the hydrolysis product (c) may contain a compound other than the polymer contained in the polymerization product (b) and impurities generated as a by-product in the hydrolysis treatment, and the hydrolysis product obtained immediately after the hydrolysis treatment.
• the decomposition product (c) may be dried and powdered, or the powdered hydrolysis product (c) may be dissolved or dispersed again in water.
• “(Meth) acrylic acid” is a general term for acrylic acid and methacrylic acid.
• (Meth) acrylic acid ester” is a general term for acrylic acid ester and methacrylic acid ester.
• (Meth) acrylonitrile” is a general term for acrylonitrile and methacrylonitrile.
• (Meth) acrylamide” is a general term for acrylamide and methacrylamide.
• Examples of the method for producing the vinylamine unit-containing polymer of the present invention include a method having the following steps (I) to (V).
• step III A step of polymerizing the monomer component in the polymerization mixture (a) to obtain a polymer containing N-vinylformamide unit and a polymerization product (b) containing formamide.
• step IV A step of drying the polymerization product (b) into a powder form between step (III) and step (V) as necessary.
• step V The process of obtaining the hydrolysis product (c) containing a vinylamine unit containing polymer by hydrolyzing the polymerization product (b) using an acid or a base.
• N-vinylformamide examples include the following methods. (1) A method of thermally decomposing N-methoxyethylformamide to obtain N-vinylformamide (Patent Document 3). (2) A method of obtaining N-vinylformamide by thermally decomposing N-cyanoethylformamide (Patent Document 4). (3) A method for obtaining N-vinylformamide from ethylene bisformamide.
• step (V) since formamide is hydrolyzed in step (V), it is not necessary to perform multistage precision distillation with reflux in step (I). Therefore, the yield of N-vinylformamide does not decrease due to decomposition or the like, and as a result, the yield of the finally obtained vinylamine unit-containing polymer does not decrease. Furthermore, N-methoxyethylformamide contained as other impurities in the crude N-vinylformamide is hydrolyzed in the step (V) and changes to a substance that does not affect the quality of the vinylamine unit-containing polymer.
• the method (2) since hydrogen cyanide is generated as a by-product, it is necessary to perform multistage precision distillation with reflux for the separation of hydrogen cyanide.
• equimolar formamide is formed with N-vinylformamide, so that it is necessary to perform multistage precision distillation with reflux.
• step (II) When the thermal decomposition product (crude N-vinylformamide) obtained by the method (1) is subjected to step (II) without performing multistage precision distillation with reflux, formamide does not polymerize and has a boiling point. Since it is high, it remains in the polymerization product (b). However, in the present invention, since formamide is hydrolyzed in step (V), some formamide may remain in the crude N-vinylformamide or the polymerization product (b).
• the content of formamide in the crude N-vinylformamide is 1 part by mass or more with respect to 100 parts by mass of N-vinylformamide. If the content of formamide is 1 part by mass or more, it is not necessary to perform multistage precision distillation with reflux, and the yield of N-vinylformamide is not reduced by decomposition or the like, resulting in the final vinylamine unit content. The yield of the polymer does not decrease.
• the content of formamide is 1 part by mass or more, a polymerization product obtained by polymerizing the monomer component in the polymerization mixture (a) prepared using crude N-vinylformamide ( Also in b), the content of formamide is 1 part by mass or more. Therefore, even if the polymerization product (b) is dried and water is sufficiently removed in the step (IV), formamide having a high boiling point remains, so that the dried polymerization product (b) does not become too hard and is powdered. It can be easily pulverized.
• the content of formamide in the crude N-vinylformamide is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 7 parts by mass or less based on 100 parts by mass of N-vinylformamide for the following reasons. .
• the preferable upper limit of the content of formamide depends on the hydrolysis rate when the formamide group of the N-vinylformamide unit-containing polymer is hydrolyzed to be a vinylamine unit-containing polymer. That is, as will be described later, in the step (V), the formamide is converted by utilizing the fact that the hydrolysis rate of the remaining formamide is sufficiently faster than the hydrolysis rate of the formamide group of the N-vinylformamide unit-containing polymer. Decompose. Therefore, if the content of formamide is larger than the hydrolysis rate difference, a large amount of formamide may remain in the hydrolysis product (c) containing the vinylamine unit-containing polymer.
• the amount (mol) of formamide contained in the crude N-vinylformamide is preferably less than the amount (mol) of formamide group to be hydrolyzed in the N-vinylformamide unit-containing polymer for the following reasons.
• the amount of the formamide group to be hydrolyzed in the N-vinylformamide unit-containing polymer is more preferably 50 mol% or less, and further preferably 30 mol% or less.
• 15 mol% of formamide groups in the N-vinylformamide unit-containing polymer are to be hydrolyzed and converted to amino groups, 15 mol% or more of formamide remains in the polymerization product (b).
• the hydrolysis of the formamide group of the N-vinylformamide unit-containing polymer further proceeds.
• the thermal decomposition product (crude N-vinylformamide) obtained by the method (1) contains methanol, high boiling components (coloring components, etc.), etc. as by-products, methanol, It is preferable to separate and purify high boiling components and the like.
• the purification method not involving reflux include a method of evaporating methanol under reduced pressure when methanol is separated. In the case of separating a high-boiling component or the like, wet-wall type simple distillation, thin film evaporation of a type that forcibly forms a thin film, and the like can be mentioned.
• the loss of N-vinylformamide associated with purification can be minimized.
• the loss of N-vinylformamide accompanying purification is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, relative to 100 parts by mass of N-vinylformamide before purification.
• step (I ′) is preferable as the step (I).
• step (I ′) Thermal decomposition of crude N-methoxyethylformamide containing N-methoxyethylformamide and formamide to obtain a thermal decomposition product containing N-vinylformamide and formamide, followed by a purification method without reflux A step of purifying the pyrolysis product to obtain crude N-vinylformamide having a formamide content of 1 part by mass or more based on 100 parts by mass of N-vinylformamide.
• a polymerization mixture (a) containing N-vinylformamide as a monomer component is prepared using crude N-vinylformamide having a formamide content of 1 part by mass or more with respect to 100 parts by mass of N-vinylformamide. Therefore, the polymerization mixture (a) contains 1 part by mass or more of formamide with respect to N-vinylformamide (100 parts by mass).
• the polymerization mixture (a) may contain a monomer other than N-vinylformamide as a monomer component.
• Other monomers include (meth) acrylic acid, (meth) acrylic acid salts, (meth) acrylic acid esters, (meth) acrylonitrile, (meth) acrylamide, N-alkyl (meth) acrylamide, N, N Dialkyl (meth) acrylamide, dialkylaminoethyl (meth) acrylamide, dialkylaminoethyl (meth) acrylamide salt or quaternary, dialkylaminopropyl (meth) acrylamide, dialkylaminopropyl (meth) acrylamide salt or quaternized , Diacetone acrylamide, N-vinyl pyrrolidone, N-vinyl caprolactam, vinyl acetate and the like.
• the proportion of N-vinylformamide in 100 mol% of the monomer component is usually 5 mol% or more, preferably 10 mol% or more, more preferably 50 mol% or more, and further preferably 70 to 100 mol%.
• the proportion of each monomer is reflected as the proportion of each constituent unit in the N-vinylformamide unit-containing polymer or the vinylamine unit-containing polymer.
• the polymerization mixture (a) may contain, in addition to the monomer component and formamide, a polymerization initiator, a solvent, other known additives, and the like as necessary. What is necessary is just to select a polymerization initiator suitably from well-known polymerization initiators according to the polymerization method employ
• the polymerization initiator include azo initiators, redox initiators, peroxide initiators, and photopolymerization initiators.
• Examples of the azo initiator include water-soluble azo initiators and oil-soluble azo initiators.
• Specific examples of water-soluble azo initiators include 2,2′-azobis (amidinopropane) dihydrochloride, 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] Examples thereof include dihydrochloride and 4,4′-azobis (4-cyanovaleric acid).
• Specific examples of oil-soluble azo initiators include 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexanecarbonitrile), 2,2′-azobis (2-methylbutyronitrile). 2,2′-azobis (2-methylpropionate), 4,4′-azobis (4-methoxy-2,4dimethyl) valeronitrile and the like.
• the redox initiator are selected from at least one of peroxides such as tert-butyl hydroperoxide and ammonium peroxodisulfate, and sodium sulfite, sodium bisulfite, trimethylamine, tetramethylethylenediamine, and ferrous sulfate.
• peroxides such as tert-butyl hydroperoxide and ammonium peroxodisulfate
• sodium sulfite sodium bisulfite, trimethylamine, tetramethylethylenediamine, and ferrous sulfate.
• ferrous sulfate since ferrous sulfate is not easily affected by impurities contained in the crude N-vinylformamide, it is sufficient even if the purity of the crude N-vinylformamide used for the preparation of the polymerization mixture (a) is low. It is preferable because a high polymerization rate can be maintained.
• peroxide initiator examples include tert-butyl hydroperoxide, ammonium peroxodisulfate, potassium peroxodisulfate, hydrogen peroxide, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, succinic peroxide, tert-butylperoxy- Examples include 2-ethylhexanoate.
• the photopolymerization initiator can be appropriately selected from known compounds. Examples include benzophenone series, benzoin series, benzoin alkyl ether series, benzyl dimethyl ketal series, ⁇ -hydroxy ketone series, bisacylphosphine oxide series photopolymerization initiators, and the like.
• solvent suitably from well-known solvents according to the polymerization method employ
• the solvent include water and hydrocarbon solvents.
• Other additives include gel improvers (polyalkylene glycols and the like), pH adjusters (phosphoric acid and the like), inorganic salts, chain transfer agents, emulsifiers (dispersion stabilizers), sensitizers and the like.
• Step (III) Examples of the polymerization method of the monomer component containing N-vinylformamide include an aqueous solution polymerization method, an aqueous solution adiabatic polymerization method, a reverse phase suspension polymerization method, an emulsion polymerization method, and a sheet-like photopolymerization method.
• the polymerization of the monomer component is usually performed at pH 5-9. When the pH is in the range of 5 to 9, hydrolysis of N-vinylformamide can be suppressed.
• the polymerization temperature varies depending on the polymerization method, but is usually 0 to 110 ° C., preferably 0 to 100 ° C.
• the molecular weight of the N-vinylformamide unit-containing polymer obtained by polymerizing the monomer component in the presence of formamide is the same as that in the absence of formamide. This is lower than the N-vinylformamide unit-containing polymer obtained by polymerization.
• the degree of decrease in molecular weight is such that the reduced viscosity is reduced by 10% when 3 parts by mass of formamide is present per 100 parts by mass of N-vinylformamide. Therefore, as long as several parts by mass of formamide are present with respect to 100 parts by mass of N-vinylformamide, a decrease in molecular weight can be suppressed by adjusting the polymerization initiator and polymerization temperature.
• the polymerization product (b) When formamide is contained in the polymerization product (b) obtained in the step (III), the polymerization product (b) is dried and powdered in the step (IV), so that pulverization becomes easy.
• the content of formamide in the polymerization product (b) is preferably 1 to 20 parts by weight, more preferably 1 to 10 parts by weight, based on 100 parts by weight of the N-vinylformamide unit-containing polymer for the following reasons. 1 to 7 parts by mass is more preferable.
• the preferable upper limit of the content of formamide depends on the hydrolysis rate when the formamide group of the N-vinylformamide unit-containing polymer is hydrolyzed to be a vinylamine unit-containing polymer.
• the formamide is converted by utilizing the fact that the hydrolysis rate of the remaining formamide is sufficiently faster than the hydrolysis rate of the formamide group of the N-vinylformamide unit-containing polymer. Decompose. Therefore, if the content of formamide is larger than the hydrolysis rate difference, a large amount of formamide may remain in the hydrolysis product (c) containing the vinylamine unit-containing polymer.
• the preferable lower limit of the content of formamide depends on the grindability of the polymerization product (b).
• step (IV) if the content of formamide is large, even if the polymerization product (b) is dried in step (IV) and the water is sufficiently removed, formamide with a high boiling point remains, so that the water content to be removed is strictly limited. Even if it does not control, the polymerization product (b) of the hardness which is easy to grind
• the state of the polymerization product (b) obtained in the step (III) is a blocky aqueous gel, and in the case of reverse phase suspension polymerization, the non-aqueous solvent is a fine particle gel. It is a dispersion.
• the polymerization product (b) may be subjected to the step (V) as it is, or may be subjected to the step (V) after the polymerization product (b) is dried and powdered.
• the polymerization product (b) after the drying is also called “dry body.”
• dry body From the viewpoint of efficiently performing the hydrolysis treatment of the polymerization product (b) in the step (V), it is preferable to dry the polymerization product (b) by a known method to form a powder.
• the powdery polymerization product (b) is again dissolved or dispersed in water and then subjected to step (V).
• the polymerization product (b) When the polymerization product (b) is dried and powdered, if a large amount of moisture remains in the polymerization product (b), the dried product is soft and difficult to grind. If the moisture is removed too much, the dried product becomes too hard and pulverization becomes difficult.
• the moisture content of the dried product is usually controlled by adjusting the drying temperature and residence time, but in the case of a polymerized product (b) having a low formamide content, the adjustment range of the drying temperature and residence time is narrow, Control of the amount of water is not easy.
• the polymerization product (b) having a high content of formamide since formamide has a high boiling point, formamide does not evaporate at the drying temperature for removing water and remains in the dried product. If formamide remains, the dried product is hard to be hardened, and the adjustment range of the drying temperature and residence time is widened. Therefore, the moisture content can be easily controlled, and as a result, a dried product that can be easily pulverized can be obtained.
• the final product is a vinylamine unit-containing polymer in which the formamide group of the N-vinylformamide unit-containing polymer is hydrolyzed.
• the hydrolysis treatment of the polymerization product (b) is performed in the presence of water. Specifically, a state of a bulky aqueous gel obtained by aqueous solution adiabatic polymerization or sheet-like photopolymerization in step (III); a non-aqueous solvent for fine particle gel obtained by reverse phase suspension polymerization in step (III) State of dispersion: The dispersion is carried out in a state where the powdered polymerization product (b) obtained in step (IV) is dissolved or dispersed in water.
• the hydrolysis treatment of the polymerization product (b) is performed in the presence of an acid or a base.
• the acid is preferably a strong acid
• the base is preferably a strong base.
• the "strong acid” is the acid dissociation constant pK a in aqueous solution at 25 ° C. means 0 following compounds.
• the "strong base” refers to bases acid dissociation constant pK b in aqueous solution at 25 ° C. means 0 following compounds.
• the strong acid monovalent mineral acids such as hydrochloric acid and nitric acid are preferable.
• As the strong base lithium hydroxide, sodium hydroxide, potassium hydroxide and the like are preferable.
• the hydrolysis rate of formamide is sufficiently faster than the hydrolysis rate of the formamide group of the N-vinylformamide unit-containing polymer.
• the hydrolysis rate of the formamide group of the N-vinylformamide unit-containing polymer is preferably 10 mol% or more out of 100 mol% of the formamide group before the hydrolysis treatment. If the target hydrolysis rate is too low, it may be difficult to accurately adjust the hydrolysis rate.
• the upper limit of the hydrolysis rate is preferably 80 mol% or less out of 100 mol% of formamide groups before the hydrolysis treatment. When hydrolyzing more than 80 mol% of the formamide group of the N-vinylformamide unit-containing polymer, an excessive amount of acid or base is required.
• the amount of acid or base may be adjusted in consideration of the amount of acid or base required for hydrolysis of the formamide group, etc. of the formamide or N-vinylformamide unit-containing polymer.
• the N-vinylformamide unit-containing polymer can be obtained at the target hydrolysis rate regardless of the content of formamide contained in the polymerization product (b). It is possible to hydrolyze the formamide group.
• the amount (mole) of formamide contained in the polymerization product (b) is preferably smaller than the amount (mole) of the formamide group to be hydrolyzed in the N-vinylformamide unit-containing polymer.
• the amount of acid or base basically depends on the amount of formamide and the amount of other low molecular weight compounds to be hydrolyzed and the amount of formamide groups to be hydrolyzed in the polymer containing N-vinylformamide units.
• the amount of substance is sufficient. In particular, when the hydrolysis rate of the formamide group of the target N-vinylformamide unit-containing polymer is low, it is necessary to adjust the amount of acid or base.
• the polymerization product (b) is preferably hydrolyzed at 50 ° C. or higher, and more preferably hydrolyzed at 50 to 100 ° C. If the temperature at the time of hydrolyzing the polymerization product (b) is 50 ° C. or higher, the hydrolysis reaction is promoted, and a desired hydrolysis rate can be obtained in a relatively short time. If the temperature at the time of hydrolyzing the polymerization product (b) is 100 ° C. or lower, a high-quality vinylamine unit-containing polymer can be obtained without causing molecular weight reduction or insolubilization due to heat.
• the time for performing the hydrolysis treatment of the polymerization product (b) is appropriately determined according to the content of formamide, the target hydrolysis rate, the temperature at which the polymerization product (b) is hydrolyzed, and the like. That's fine.
• the content of formamide in the hydrolysis product (c) is preferably 0.1 parts by mass or less and more preferably 0.05 parts by mass or less with respect to 100 parts by mass of the vinylamine unit-containing polymer.
• the content of formamide is 0.1 parts by mass or less, the influence on the quality of the vinylamine unit-containing polymer can be sufficiently reduced.
• the hydrolysis product (c) includes ammonia and formic acid generated by hydrolysis of formamide, formic acid generated by hydrolysis of formamide group of N-vinylformamide unit-containing polymer, and N-methoxyethylformamide. Ammonia, formic acid, and acetaldehyde.
• Formic acid may be removed by a known method. Specifically, a method of adding alcohol under acidic conditions, esterifying and distilling off can be mentioned. Ammonia may be removed by aeration through nitrogen, air or the like, or may be retained in the hydrolysis product (c) in a salt state by neutralization. Acetaldehyde is preferably removed by a known method because it may cause cross-linking insolubilization of the vinylamine unit-containing polymer during the hydrolysis treatment. Specific examples include a method of reducing with a reducing agent and a method of oximation with hydroxylamine.
• an acid preferably a strong acid
• a base preferably a strong base
• formamide is sufficiently hydrolyzed. Therefore, high-quality vinylamine with little formamide contamination despite the use of crude N-vinylformamide whose raw material is 1 part by mass or more with respect to 100 parts by mass of N-vinylformamide.
• a unit-containing polymer can be produced.
• the polymerization mixture has a content of formamide of 1 part by mass or more with respect to 100 parts by mass of N-vinylformamide. Even if the monomer component containing N-vinylformamide is polymerized in (a), a decrease in the molecular weight (reduced viscosity) of the N-vinylformamide unit-containing polymer can be suppressed. Therefore, the fall of the molecular weight (reduced viscosity) of the vinylamine unit containing polymer finally obtained can also be suppressed.
• the process (I) is a process for producing crude N-vinylformamide by using crude N-vinylformamide having a formamide content of 1 part by mass or more with respect to 100 parts by mass of N-vinylformamide as a raw material.
• the purification of crude N-vinylformamide can be omitted, or the purification of crude N-vinylformamide can be carried out by a purification method without reflux. That is, the process (I) can be simplified as compared with the conventional multistage precision distillation with reflux. As a result, the following advantages are also obtained.
• -Since step (I) can be simplified, crude N-vinylformamide can be produced at low cost, and the resulting vinylamine unit-containing polymer can also be produced at low cost.
• -Since it is not necessary to perform multistage precision distillation with reflux in step (I), the yield of N-vinylformamide is not reduced by decomposition or the like, and as a result, the yield of the vinylamine unit-containing polymer finally obtained is It does not decline.
• process (I) can be performed comparatively safely.
• the content of formamide is 1 part by mass or more with respect to 100 parts by mass of the N-vinylformamide unit-containing polymer. Even if water is sufficiently removed, formamide having a high boiling point remains. Therefore, the dried polymerization product does not become too hard and can be easily pulverized when powdered.
• ⁇ sp / C (t ⁇ t 0 ) / t 0 /0.1
• ⁇ sp / C the reduced viscosity (dL / g)
• t the flow time (seconds) of the sample solution
• t 0 the flow time (seconds) of 1N saline.
• the hydrolysis product (c) containing the vinylamine unit-containing polymer was dissolved in 1N saline so that the concentration of the vinylamine unit-containing polymer was 0.1 g / dL to obtain a sample solution.
• the flow time of the sample solution was measured using an Ostwald viscometer.
• the flow time of 1N saline was measured, and the reduced viscosity of the vinylamine unit-containing polymer was determined by the following formula.
• ⁇ sp / C (t ⁇ t 0 ) / t 0 /0.1
• ⁇ sp / C the reduced viscosity (dL / g)
• t the flow time (seconds) of the sample solution
• t 0 the flow time (seconds) of 1N saline.
• the content (parts by mass) of formamide and N-methoxyethylformamide with respect to the N-vinylformamide unit-containing polymer (100 parts by mass) The content (parts by mass) was determined.
• Analysis system LC analysis system manufactured by Shimadzu Corporation Column: ODP column (ShodexODP 4.6 mm ⁇ 250 mmH), Eluent: 0.01 mol / L sodium dihydrogen phosphate aqueous solution, Flow rate: 1 mL / min, Analysis temperature: 40 ° C. Sample injection volume: 20 ⁇ L, Detector: UV detector (wavelength 200 nm).
• Analysis system LC analysis system manufactured by Shimadzu Corporation Column: ODP column (ShodexODP 4.6 mm ⁇ 250 mmH), Eluent: 0.01 mol / L sodium dihydrogen phosphate aqueous solution, Flow rate: 1 mL / min, Analysis temperature: 40 ° C. Sample injection volume: 20 ⁇ L, Detector: UV detector (wavelength 200 nm).
• the content of formamide is 5.5 parts by mass with respect to 100 parts by mass of N-vinylformamide, the content of N-methoxyethylformamide is 2.4 parts by mass, The content was 47 parts by mass, and the others (high boiling components, etc.) were 6.6 parts by mass.
• Methanol was distilled off from the pyrolysis product under a reduced pressure of 100 mmHg. Further, using a horizontal centrifugal thin film evaporator, thin film evaporation was performed under conditions of 3 mmHg and 71 ° C. to obtain crude N-vinylformamide.
• the content of formamide was 6.5 parts by mass and the content of N-methoxyethylformamide was 2.2 parts by mass with respect to 100 parts by mass of N-vinylformamide.
• the monomer adjustment liquid was cooled to 0 ° C., it was transferred to an adiabatic reaction vessel equipped with a thermometer and aerated with nitrogen for 15 minutes.
• a 10% by mass aqueous solution of 2,2′-azobis (2-amidinopropane) dihydrochloride (manufactured by Wako Pure Chemical Industries, Ltd., V-50) was added to the monomer adjusting solution with respect to 100 parts by mass of N-vinylformamide.
• 2,2′-Azobis (2-amidinopropane) dihydrochloride was added so as to be 0.15 parts by mass.
• a 10% by mass aqueous solution of tert-butyl hydroperoxide (Nippon Yushi Co., Ltd., Perbutyl H-69) is 0.03 parts by mass of tert-butyl hydroperoxide with respect to N-vinylformamide (100 parts by mass).
• a 10% by mass aqueous solution of sodium hydrogen sulfite was added so that the sodium hydrogen sulfite was 0.04 parts by mass with respect to 100 parts by mass of N-vinylformamide, whereby N -Polymerization of vinylformamide was started.
• Example 1 (Production of purified N-vinylformamide)
• Example 1 using a rectification column (13 stages) with a diameter of 5 cm packed with regular priority material (Sruzer Lab Packing), using a raw material supply stage: 5th stage, tower top: reduced pressure of 4 mmHg, reflux ratio: 2.
• the crude N-vinylformamide obtained in (1) was subjected to multistage precision distillation to obtain purified N-vinylformamide from the top of the column. During the distillation, parabenzoquinone was added to the crude N-vinylformamide so that the amount was 0.03 parts by mass with respect to N-vinylformamide (100 parts by mass).
• the content of formamide was 0.8 parts by mass and the content of N-methoxyethylformamide was 0.2 parts by mass with respect to 100 parts by mass of N-vinylformamide.
• the yield of N-vinylformamide from crude N-vinylformamide was 86% by mass.
• the monomer adjustment liquid was cooled to 0 ° C., it was transferred to an adiabatic reaction vessel equipped with a thermometer and aerated with nitrogen for 15 minutes.
• a 10% by mass aqueous solution of 2,2′-azobis (2-amidinopropane) dihydrochloride (manufactured by Wako Pure Chemical Industries, Ltd., V-50) is added to N-vinylformamide (100 parts by mass) as a monomer adjustment solution.
• 2,2′-azobis (2-amidinopropane) dihydrochloride was added so as to be 0.15 parts by mass.
• a 10% by mass aqueous solution of tert-butyl hydroperoxide (Nippon Yushi Co., Ltd., Perbutyl H-69) was added so that the tert-butyl hydroperoxide was 0.02 parts by mass with respect to 100 parts by mass of N-vinylformamide. Added. Furthermore, a 10% by mass aqueous solution of sodium hydrogen sulfite was added so that the sodium hydrogen sulfite was 0.02 parts by mass with respect to 100 parts by mass of N-vinylformamide, whereby N 2 -Polymerization of vinylformamide was started.
• Step (II) to Step (III): Reversed Phase Suspension Polymerization After mixing deionized water and the crude N-vinylformamide obtained in Example 1 (amount of N-vinylformamide to be 80 g) to a total of 95 g, sodium hypophosphite (N-vinylformamide) was mixed. 0.025 parts by mass with respect to 100 parts by mass) 2,2′-azobis (2-amidinopropane) dihydrochloride (manufactured by Wako Pure Chemical Industries, V-50) (N-vinylformamide 100 parts by mass) The amount of 0.4 parts by mass) was added to obtain a polymerization mixture (a).
• Deionized water and the purified N-vinylformamide obtained in Comparative Example 1 (amount to give 80 g of N-vinylformamide) were mixed to a total of 95 g, and then sodium hypophosphite (N-vinylformamide). 0.02 parts by mass with respect to 100 parts by mass) 2,2′-azobis (2-amidinopropane) dihydrochloride (manufactured by Wako Pure Chemical Industries, V-50) (N-vinylformamide 100 parts by mass) The amount of 0.4 parts by mass) was added to obtain a polymerization mixture (a).
• Example 3 In addition to the polymerization initiator used in Example 1, 5 parts by weight of an aqueous ferrous sulfate solution (0.005 parts by weight of ferrous sulfate with respect to 100 parts by weight of N-vinylformamide) was added. Polymerization was carried out in the same manner as in Example 1. The time for the system temperature to reach the maximum temperature was 240 minutes, compared with 310 minutes in Example 1, and the polymerization rate was improved.
• step (II) As described above, adjustment of polymerization conditions for both aqueous adiabatic polymerization and reverse phase suspension polymerization is possible even when crude N-vinylformamide is used in step (II) without performing multistage precision distillation with reflux in step (I). As a result, a polymer having substantially the same molecular weight (reduced viscosity) as that obtained when purified N-vinylformamide was used was obtained. Further, even when crude N-vinylformamide is used in step (II), formamide is very little mixed into the vinylamine unit-containing polymer obtained in step (V).
• Examples 1 and 2 in which the multistage precision distillation with reflux in Step (I) was not performed were compared with Comparative Examples 1 and 2 in which the multistage precision distillation with reflux in Step (I) was performed. Greatly improved.
• Example 1 having a high formamide content is easier to grind than Comparative Example 1 having a low formamide content.
• the time required from pulverization to passing through the sieve was half of 15 minutes.
• Example 3 using ferrous sulfate as a polymerization initiator compared with Example 1, the time for the system temperature to reach the maximum temperature was shortened, and the polymerization rate was improved.
• the vinylamine unit-containing polymer obtained by the production method of the present invention is useful as a flocculant, a papermaking agent, a fiber treatment agent and the like.

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