Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L59/00—Compositions of polyacetals; Compositions of derivatives of polyacetals
  • C08L59/04—Copolyoxymethylenes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G2/00—Addition polymers of aldehydes or cyclic oligomers thereof or of ketones; Addition copolymers thereof with less than 50 molar percent of other substances
  • C08G2/06—Catalysts
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G2/00—Addition polymers of aldehydes or cyclic oligomers thereof or of ketones; Addition copolymers thereof with less than 50 molar percent of other substances
  • C08G2/18—Copolymerisation of aldehydes or ketones
  • C08G2/20—Copolymerisation of aldehydes or ketones with other aldehydes or ketones

Definitions

• the present invention relates to a cationic polymerization initiator composition, and a method for producing an oxymethylene copolymer and a molded article using the same.
• Oxymethylene copolymers have traditionally been widely used in electronic devices, vehicles, etc. as fibers, films, gears, bearings, etc., due to their excellent strength, elasticity, impact resistance, and sliding properties.
• a cationic polymerization initiator is usually used.
• Patent Document 1 describes an invention relating to a method for transporting a solution containing a cationic polymerization catalyst (cationic polymerization initiator) and an organic solvent through a pipe, in which the arithmetic mean surface roughness (Ra) of the inner wall of the pipe is 3 ⁇ m or less.
• Patent Document 1 describes that the invention can suppress the generation of scale (deposits formed within the pipe) caused by aggregation of the cationic polymerization initiator, and can produce oxymethylene copolymers stably over a long period of time with a high yield.
• cationic polymerization initiators particularly those containing fluorine atoms (fluorine-containing cationic polymerization initiators), can corrode metals that make up pipes, tanks, etc.
• the present invention therefore provides a means for preventing metal corrosion caused by fluorine atom-containing cationic polymerization initiators.
• the present invention is, for example, as follows:
• a cationic polymerization initiator composition comprising a fluorine atom-containing cationic polymerization initiator (A) and a hydrophilic ether solvent (B) having no acetal structure and no active hydroxyl group, A cationic polymerization initiator composition, wherein the content of the hydrophilic ether solvent (B) is 2.5 mass% or more based on the total mass of the cationic polymerization initiator composition.
• a method for producing an oxymethylene copolymer comprising a polymerization step of obtaining an oxymethylene polymer from a reaction solution containing a polymerization raw material (C) containing 1,3,5-trioxane and the cationic polymerization initiator composition according to any one of [1] to [7] above.
• the production method according to the above [9] wherein the content of the hydrophilic ether solvent (B) in the reaction solution is 18 to 100 ppm relative to 1,3,5-trioxane.
• a method for producing a molded article comprising molding an oxymethylene polymer produced by the method according to any one of [8] to [10] above.
• the present invention it is possible to prevent metal corrosion caused by the fluorine atom-containing cationic polymerization initiator. This makes it possible to suppress, for example, deterioration of the manufacturing equipment, a decrease in the productivity of the oxymethylene copolymer, and a decrease in the physical properties of the obtained oxymethylene copolymer.
• Cationic polymerization initiator composition The cationic polymerization initiator composition according to the present invention comprises a fluorine atom-containing cationic polymerization initiator (A) and a hydrophilic ether solvent (B) having neither an acetal structure nor an active hydroxyl group, wherein the content of the hydrophilic ether solvent (B) is 2.5 mass% or more based on the total mass of the cationic polymerization initiator composition.
• the cationic polymerization initiator composition according to the present invention can prevent metal corrosion caused by the fluorine atom-containing cationic polymerization initiator (A).
• the reasons for this are, for example, as follows. That is, when a cationic polymerization initiator containing fluorine atoms (fluorine atom-containing cationic polymerization initiator (A)) is used, metal corrosive components such as hydrofluoric acid (HF) may be generated by the water present in the system. In such cases, the metal corrosive components corrode the metals constituting the pipes, tanks, etc., and the manufacturing equipment such as the pipes and tanks is likely to deteriorate. In addition, the metal components eluted by the metal corrosion may inhibit the polymerization reaction, which may cause a decrease in the productivity of the oxymethylene copolymer and a decrease in the physical properties of the obtained oxymethylene copolymer.
• the cationic polymerization initiator composition according to the present invention contains a fluorine atom-containing cationic polymerization initiator (A) and a predetermined amount of a hydrophilic ether solvent (B) (hereinafter, sometimes simply referred to as "hydrophilic ether solvent (B)”) that does not have an acetal structure and an active hydroxyl group.
• a hydrophilic ether solvent (B) hereinafter, sometimes simply referred to as "hydrophilic ether solvent (B)
• the generation of metal corrosive components can be suppressed. This makes it possible to suppress metal corrosion constituting pipes, tanks, etc., and to suppress deterioration of manufacturing equipment.
• the suppression of metal corrosion also suppresses the elution of metal components, it is possible to prevent inhibition of the polymerization reaction by metal components. As a result, it is possible to suppress a decrease in the productivity of oxymethylene copolymers and a decrease in the physical properties of the obtained oxymethylene copolymers.
• Fluorine atom-containing cationic polymerization initiator (A) The fluorine atom-containing cationic polymerization initiator (A) has a function of acting on 1,3,5-trioxane and/or a comonomer to generate cationic active species and promote the copolymerization reaction.
• the fluorine atom-containing cationic polymerization initiator (A) is not particularly limited, but examples include boron trifluoride compounds, fluoroaryl boron compounds, and fluorine atom-containing protonic acids.
• boron trifluoride compound examples include boron trifluoride dimethyl ether complex ( BF3.Me2O ), boron trifluoride diethyl ether complex ( BF3.Et2O ), boron trifluoride dibutyl ether complex ( BF3.Bu2O ), boron trifluoride tetrahydrofuran complex ( BF3.THF ) , boron trifluoride dihydrate ( BF3.2H2O ), boron trifluoride methanol complex ( BF3.CH3OH ) , boron trifluoride phenol complex ( BF3.2C6H5OH ), boron trifluoride acetate complex (BF3.2CH3COOH ) , and boron trifluoride ethylamine complex ( BF3.C2H5NH2 ).
• the fluoroaryl boron compounds include, for example, triphenylborane, tris(pentafluorophenyl)borane (TPB), bis(pentafluorophenyl)fluoroborane, pentafluorophenyldifluoroborane, tris(2,3,4,5-tetrafluorophenyl)borane, tris(2,3,4,6-tetrafluorophenyl)borane, tris(2,3,5,6-tetrafluorophenyl)borane, tris(2,3,5-trifluorophenyl)borane, tris(2,4,6-trifluorophenyl)boron, tris(1,3-difluorophenyl)boron, tris(2,3,5,6-tetrafluoro-4-methylphenyl)boron, tris(2,3,4,6-tetrafluoro-5-methylphenyl)boron, tris(2,4,5-triflu
• fluoroaryl boron compounds may be coordination compounds coordinated with water (hydrates), ammonia, dimethyl ether, diethyl ether, dibutyl ether, phenol, ethylamine, and the like, and such coordination compounds are included in the fluoroaryl boron compounds.
• the fluorine atom-containing protonic acid is not particularly limited, but examples thereof include trifluoroacetic acid (CF 3 COOH) and trifluoromethanesulfonic acid (CF 3 SO 3 H).
• the fluorine atom-containing cationic polymerization initiator (A) preferably contains a boron trifluoride compound, more preferably contains at least one selected from the group consisting of boron trifluoride dimethyl ether complex (BF3.Me2O), boron trifluoride diethyl ether complex (BF3.Et2O), boron trifluoride dibutyl ether complex (BF3.Bu2O ) , and boron trifluoride tetrahydrofuran complex ( BF3.THF ), and further preferably contains boron trifluoride diethyl ether complex ( BF3.Et2O ).
• boron trifluoride dimethyl ether complex BF3.Me2O
• BF3.Et2O boron trifluoride diethyl ether complex
• BF3.Bu2O boron trifluoride dibutyl ether complex
• BF3.THF boron trifluoride tetrahydrofur
• the fluorine atom-containing cationic polymerization initiator (A) preferably contains a fluoroaryl boron compound, such as tris(pentafluorophenyl)borane (TPB), bis(pentafluorophenyl)fluoroborane, pentafluorophenyl difluoroborane, tris(2,3,4,5-tetrafluorophenyl)borane, tris(2,3,4,6-tetrafluorophenyl)borane, tris(2,3,5,6-tetrafluorophenyl)borane, or tris(2,3,5-trifluorophenyl)borane.
• TPB tris(pentafluorophenyl)borane
• TPB tris(pentafluorophenyl)borane
• bis(pentafluorophenyl)fluoroborane pentafluorophenyl difluoroborane
• the fluorine atom-containing cationic polymerization initiator (A) preferably contains at least one selected from the group consisting of boron trifluoride compounds and fluoroaryl boron compounds, and examples of such compounds include boron trifluoride dimethyl ether complex ( BF3.Me2O ), boron trifluoride diethyl ether complex ( BF3.Et2O ), boron trifluoride dibutyl ether complex ( BF3.Bu2O ), and boron trifluoride tetrahydrofuran complex (BF and at least one selected from the group consisting of tris (pentafluorophenyl)borane (TPB), bis(pentafluorophenyl)fluoroborane, pentafluorophenyldifluoroborane, tris(2,3,4,5-tetrafluorophenyl)borane, tris(2,3,4,6-tetrafluorophenyl)bor
• the above-mentioned fluorine atom-containing cationic polymerization initiator (A) may be used alone or in combination of two or more kinds.
• the content of the fluorine atom-containing cationic polymerization initiator (A) is preferably 0.1 to 20 mass%, more preferably 0.5 to 15 mass%, even more preferably 1 to 10 mass%, and particularly preferably 5 to 10 mass%, based on the total mass of the cationic polymerization initiator composition.
• the total content is within the above range.
• the fluorine atom-containing cationic polymerization initiator (A) contains a boron trifluoride compound
• the content of the boron trifluoride compound is preferably 1 to 20 mass%, more preferably 2 to 15 mass%, even more preferably 3 to 10 mass%, and particularly preferably 5 to 10 mass%, based on the total mass of the cationic polymerization initiator composition.
• the fluorine atom-containing cationic polymerization initiator (A) contains a fluoroaryl boron compound
• the content of the fluoroaryl boron compound is preferably 0.1 to 10 mass%, more preferably 0.1 to 5 mass%, even more preferably 0.1 to 3 mass%, and particularly preferably 0.1 to 1 mass%, based on the total mass of the cationic polymerization initiator composition.
• the cationic polymerization initiator composition may contain other polymerization initiators.
• other polymerization initiator refers to a cationic polymerization initiator other than the fluorine atom-containing cationic polymerization initiator (A), in other words, a fluorine atom-free cationic polymerization initiator.
• polymerization initiators include, but are not limited to, fluorine atom-free Lewis acids and fluorine atom-free protonic acids.
• fluorine atom-free Lewis acid examples include boron trichloride (BCl 3 ), aluminum chloride (AlCl 3 ), tin tetrachloride (SnCl 4 ), zinc chloride (ZnCl 2 ), iron chloride (FeCl 3 ), gallium chloride (GaCl 3 ), zirconium chloride (ZrCl 4 ), and niobium pentachloride (NbCl 5 ).
• fluorine atom-free protonic acid examples include perchloric acid (HClO 4 ), hydrogen chloride (HCl), sulfuric acid (H 2 SO 4 ), trichloroacetic acid (CCl 3 COOH), p-toluenesulfonic acid, phosphotungstic acid, and derivatives thereof.
• Examples of the derivatives of the fluorine-free protonic acid include perchloric anhydride and peroxyacetyl perchlorate.
• polymerization initiators may be used alone or in combination of two or more.
• the content of the other polymerization initiator is preferably 0.1 to 20 mass%, more preferably 0.1 to 15 mass%, and even more preferably 0.5 to 10 mass%, based on the total mass of the cationic polymerization initiator composition. When two or more types of other polymerization initiators are included, it is preferable that the total content is within the above range.
• Hydrophilic ether solvent (B) having neither an acetal structure nor an active hydroxyl group
• the hydrophilic ether solvent (B) has a function of suppressing the generation of metal corrosive components such as hydrofluoric acid (HF) that may be generated when the fluorine atom-containing cationic polymerization initiator (A) comes into contact with water.
• metal corrosive components such as hydrofluoric acid (HF) that may be generated when the fluorine atom-containing cationic polymerization initiator (A) comes into contact with water.
• HF hydrofluoric acid
• This makes it possible to prevent metal corrosion caused by the metal corrosive components.
• it is possible to prevent inhibition of the polymerization reaction caused by metal components eluted by metal corrosion and as a result, it is possible to suppress a decrease in the productivity of the oxymethylene copolymer and a decrease in the physical properties of the obtained oxymethylene copolymer.
• Hydrophilic ether solvents (B) include linear ethers containing one oxygen atom, cyclic ethers containing one oxygen atom, linear ethers containing two or more oxygen atoms, and cyclic ethers containing two or more oxygen atoms.
• chain ethers containing one oxygen atom examples include dimethyl ether, diethyl ether, and ethyl methyl ether.
• cyclic ethers containing one oxygen atom examples include four-membered cyclic ethers containing one oxygen atom, such as oxetane, 2-methyloxetane, 3-methyloxetane, 2-ethyloxetane, 3-ethyloxetane, 2-propyloxetane, 2,2-dimethyloxetane, 3,3-dimethyloxetane, 2,3-dimethyloxetane, and 2-ethyl-3-methyloxetane; tetrahydrofuran (THF), 2-methyltetrahydrofuran (MHF), 3-methyltetrahydrofuran, 2-ethyltetrahydrofuran, 3-ethyltetrahydrofuran, 2-propyltetrahydrofuran, 2,2-dimethyltetrahydrofuran, 3,3-dimethyltetrahydrofuran, 2,3-dimethyltetrahydro
• cyclic ethers containing one oxygen atom such as tetrahydrofuran, 2-ethyl-3-methyltetrahydrofuran, and 2-ethyl-4-methyltetrahydrofuran; and six-membered cyclic ethers containing one oxygen atom, such as tetrahydropyran, 2-methyltetrahydropyran, 3-methyltetrahydropyran, 4-methyltetrahydropyran (MTHP), 2-ethyltetrahydropyran, 3-ethyltetrahydropyran, 4-ethyltetrahydropyran, 2-propyltetrahydropyran, 2,2-dimethyltetrahydropyran, 3,3-dimethyltetrahydropyran, 4,4-dimethyltetrahydropyran, 2,3-dimethyltetrahydropyran, 2,5-dimethyltetrahydropyran, and 2-ethyl-5-methylt
• chain ethers containing two or more oxygen atoms include chain ethers containing two oxygen atoms such as dimethoxymethane (methylal), diethoxymethane, dipropyloxymethane, diisopropyloxymethane, dibutoxymethane, 1,2-dimethoxyethane (DME), 1,2-diethoxyethane, 1,3-dimethoxypropane, and 1,3-diethoxypropane; chain ethers containing three oxygen atoms such as trimethyl orthoformate (methoxymethylal), triethyl orthoformate, triisopropyl orthoformate, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and diethylene glycol dibutyl ether; and chain ethers containing four or more oxygen atoms such as triethylene glycol dimethyl ether, triethylene glycol diethyl ether, polyethylene glycol dimethyl ether, and polyethylene glycol diethyl ether.
• DME 1,
• Cyclic ethers containing two or more oxygen atoms include, for example, cyclic ethers containing two oxygen atoms such as 1,4-dioxane, 2-methyl-1,3-dioxane, and 4-methyl-1,3-dioxane; and cyclic ethers containing three or more oxygen atoms such as 12-crown-4, 15-crown-5, 18-crown-6, and dibenzo-18-crown-6.
• the hydrophilic ether solvent (B) preferably contains at least one of a chain ether containing two or more oxygen atoms and a cyclic ether containing two or more oxygen atoms, more preferably contains at least one of a chain ether containing two oxygen atoms and a cyclic ether containing two oxygen atoms, further preferably contains at least one selected from the group consisting of dimethoxymethane, diethoxymethane, 1,2-dimethoxyethane (DME), 1,2-diethoxyethane, and 1,4-dioxane, and particularly preferably contains at least one selected from the group consisting of 1,2-dimethoxyethane (DME), 1,2-diethoxyethane, and 1,4-dioxane.
• DME 1,2-dimethoxyethane
• 1,2-diethoxyethane 1,4-dioxane
• the compound contains at least one of a linear ether containing one oxygen atom and a cyclic ether containing one oxygen atom, more preferable that the compound contains a cyclic ether containing one oxygen atom, even more preferable that the compound contains at least one of a 4-membered cyclic ether containing one oxygen atom and a 5-membered cyclic ether containing one oxygen atom, and particularly preferable that the compound contains a 5-membered cyclic ether containing one oxygen atom, and most preferable that the compound contains at least one selected from the group consisting of tetrahydrofuran (THF), 2-methyltetrahydrofuran (MHF), 3-methyltetrahydrofuran, 2-ethyltetrahydrofuran, and 3-ethyltetrahydrofuran.
• THF tetrahydrofuran
• MHF 2-methyltetrahydrofuran
• 3-methyltetrahydrofuran 2-ethyltetrahydro
• hydrophilic ether solvents (B) may be used alone or in combination of two or more kinds.
• the content of the hydrophilic ether solvent (B) is 2.5% by mass or more, preferably 2.5 to 99% by mass, more preferably 2.5 to 60% by mass, even more preferably 2.5 to 40% by mass, particularly preferably 20 to 20% by mass, and most preferably 2.5 to 8% by mass, based on the total mass of the cationic polymerization initiator composition.
• the content of the hydrophilic ether solvent (B) is 2.5% by mass or more, preferably 2.5 to 99% by mass, more preferably 2.5 to 60% by mass, even more preferably 2.5 to 40% by mass, particularly preferably 20 to 20% by mass, and most preferably 2.5 to 8% by mass, based on the total mass of the cationic polymerization initiator composition.
• it is preferable that the total content is within the above range.
• the hydrophilic ether solvent (B) contains at least one of a chain ether containing two or more oxygen atoms and a cyclic ether containing two or more oxygen atoms
• the content of the hydrophilic ether solvent (B) is preferably 2.5 to 60 mass%, more preferably 2.5 to 20 mass%, and even more preferably 2.5 to 8 mass%, based on the total mass of the cationic polymerization initiator composition.
• the content of the hydrophilic ether solvent (B) is preferably 2.5 to 20 mass%, more preferably 2.5 to 8 mass%, and even more preferably 2.5 to 5 mass%, based on the total mass of the cationic polymerization initiator composition.
• the cationic polymerization initiator composition may contain other solvents.
• other solvents means solvents other than the hydrophilic ether solvent (B) that does not have an acetal structure and an active hydroxyl group. By using other solvents, the polymerization reaction can be controlled.
• solvents include, but are not limited to, aliphatic hydrocarbons such as hexane, heptane, and cyclohexane; aromatic hydrocarbons such as benzene, toluene, and xylene. These other solvents may be used alone or in combination of two or more.
• the content of the other solvent is preferably 1 to 95 mass% relative to the total mass of the cationic polymerization initiator composition, more preferably 10 to 95 mass%, even more preferably 40 to 95 mass%, particularly preferably 70 to 95 mass%, and most preferably 85 to 95 mass%.
• the total content is within the above range.
• the cationic polymerization initiator composition may contain water.
• the water is usually derived from water present in the atmosphere, water derived from a component contained in the cationic polymerization initiator composition (e.g., water derived from tris(pentafluorophenyl)borane (TPB) trihydrate), or water that has been intentionally added as necessary.
• a component contained in the cationic polymerization initiator composition e.g., water derived from tris(pentafluorophenyl)borane (TPB) trihydrate
• TPB tris(pentafluorophenyl)borane
• the water content is preferably 1500 ppm or less, more preferably 10 to 1000 ppm, and even more preferably 50 to 750 ppm, based on the total mass of the cationic polymerization initiator composition.
• the method for producing an oxymethylene copolymer includes a polymerization step of obtaining an oxymethylene polymer from a reaction solution containing a polymerization raw material (C) containing 1,3,5-trioxane and the above-mentioned cationic polymerization initiator composition.
• the method may further include a stabilization step, an additive addition step, and the like, as necessary.
• the polymerization step is a step of obtaining an oxymethylene polymer from a reaction solution containing a polymerization raw material (C) including 1,3,5-trioxane (hereinafter also simply referred to as "trioxane”) and the cationic polymerization initiator composition in the step of obtaining the above-mentioned combination.
• C polymerization raw material
• trioxane 1,3,5-trioxane
• reaction solution contains the polymerization raw material (C) and the above-mentioned cationic polymerization initiator composition.
• the polymerization raw material (C) contains trioxane.
• the polymerization raw material (C) may further contain a comonomer, a chain transfer agent, etc.
• Trioxane undergoes ring-opening polymerization during the polymerization reaction, resulting in the oxymethylene unit ([—CH 2 O—] n ) of the oxymethylene copolymer.
• the trioxane content is preferably 80.0 to 99.9 mass%, and more preferably 90.0 to 99.5 mass%, based on the total mass of the polymerization raw material (C).
• the comonomer is a monomer other than trioxane that can be copolymerized with trioxane.
• the comonomer improves the thermal stability of the oxymethylene copolymer.
• the comonomer exists as an amorphous component in the oxymethylene copolymer.
• Comonomers are not particularly limited, but include 1,3-dioxolane, 2-ethyl-1,3-dioxolane, 2-propyl-1,3-dioxolane, 2-butyl-1,3-dioxolane, 2,2-dimethyl-1,3-dioxolane, 2-phenyl-2-methyl-1,3-dioxolane, 4-methyl-1,3-dioxolane, 2,4-dimethyl-1,3-dioxolane, 2-ethyl-4-methyl-1,3-dioxolane, 4,4-dimethyl-1,3-dioxolane, 4,5-dimethyl-1,3-dioxolane, 2,2,4-trimethyl-1,3-dioxolane, 4 -Hydroxymethyl-1,3-dioxolane, 4-butyloxymethyl-1,3-dioxolane, 4-phenoxymethyl-1,3-dioxolane, 4-
• the comonomer contains a comonomer that induces an oxyethylene unit, more preferably contains 1,3-dioxolane and/or ethylene oxide, and even more preferably contains 1,3-dioxolane.
• the comonomer content is preferably 0.1 to 20 mass% and more preferably 0.5 to 10 mass% based on the total mass of the polymerization raw material (C).
• the chain transfer agent has the function of adjusting the molecular weight of the oxymethylene copolymer.
• the chain transfer agent is not particularly limited, but includes protic compounds such as water, formic acid, methanol, formaldehyde, phenol, and 2,6-dimethylphenol; and ether compounds such as dimethoxymethane (methylal), trimethyl orthoformate (methoxymethylal), and dibutoxymethane. These chain transfer agents may be used alone or in combination of two or more.
• the chain transfer agent preferably contains an ether compound, and more preferably contains methylal, since the terminals of the resulting oxymethylene copolymer are end-capped with stable methoxy groups (-OCH 3 ).
• the chain transfer agent may be one derived from the trioxane production process or one added separately, but it is preferable that it is one added separately.
• chain transfer agents derived from the trioxane production process include water, formic acid, methanol, and formaldehyde. These chain transfer agents derived from the trioxane production process are preferably removed before the copolymerization reaction by purifying the trioxane by distillation or the like.
• cationic polymerization initiator composition As the cationic polymerization initiator composition, the above-mentioned one is used.
• composition of reaction solution The composition of the reaction solution can be set depending on the reaction conditions, the desired physical properties of the oxymethylene copolymer, and the like.
• the content of the comonomer in the reaction solution is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 7.5 parts by mass, even more preferably 0.1 to 5.0 parts by mass, and particularly preferably 0.3 to 1.0 parts by mass, relative to 100 parts by mass of trioxane.
• the content of the comonomer in the reaction solution is preferably 0.001 to 1 mol, more preferably 0.001 to 0.1 mol, even more preferably 0.001 to 0.05 mol, and particularly preferably 0.003 to 0.01 mol, per 1 mol of trioxane.
• the content of the fluorine atom-containing cationic polymerization initiator (A) in the reaction solution is preferably 10 to 100 ppm, more preferably 20 to 80 ppm, and even more preferably 30 to 60 ppm, relative to trioxane.
• the content of the fluorine atom-containing cationic polymerization initiator (A) in the reaction solution is preferably 0.00001 to 1 mmol, more preferably 0.001 to 0.5 mmol, even more preferably 0.005 to 0.1 mmol, and even more preferably 0.01 to 0.05 mmol, per 1 mol of trioxane.
• the content of other polymerization initiators in the reaction solution is preferably 10 to 100 ppm relative to trioxane, more preferably 20 to 80 ppm, and even more preferably 30 to 60 ppm.
• the content of the other polymerization initiator in the reaction solution is preferably 0.00001 to 1 mmol, more preferably 0.001 to 0.5 mmol, even more preferably 0.005 to 0.1 mmol, and even more preferably 0.01 to 0.05 mmol, per 1 mol of trioxane.
• the content of the hydrophilic ether solvent (B) in the reaction solution is preferably 18 ppm or more, more preferably 18 to 1000 ppm, even more preferably 18 to 300 ppm, particularly preferably 18 to 100 ppm, and most preferably 18 to 50 ppm, relative to trioxane.
• the content of other solvents in the reaction solution is preferably 10 to 1500 ppm, more preferably 100 to 1000 ppm, even more preferably 300 to 900 ppm, and particularly preferably 600 to 800 ppm, per 1 mol of trioxane.
• the reaction solution is prepared by mixing the polymerization raw material (C) with the cationic polymerization initiator composition described above. However, depending on the composition of the polymerization raw material (C) and the cationic polymerization initiator composition, appropriate components (comonomers, chain transfer agents, etc.) can be added to the reaction solution. For example, if the total content of the chain transfer agent in the polymerization raw material (C) and the cationic polymerization initiator composition is insufficient for a set value, the chain transfer agent can be added to the reaction solution to adjust the content of the chain transfer agent in the reaction solution.
• an oxymethylene polymer is obtained from the reaction solution by copolymerizing trioxane and a comonomer in the presence of a fluorine atom-containing cationic polymerization initiator (A) and a hydrophilic ether solvent (B).
• the copolymerization reaction temperature is preferably 50 to 150°C, and more preferably 60 to 120°C.
• the copolymerization reaction time is preferably 0.1 to 60 minutes, and more preferably 1 to 30 minutes.
• a polymerization terminator to deactivate the fluorine atom-containing cationic polymerization initiator (A) and/or the cationic active species to terminate the copolymerization reaction.
• Polymerization terminators include, but are not limited to, triphenylphosphine; ammonia; amines such as diethylamine, triethylamine, and tributylamine; and ethanolamines such as triethanolamine, N-methyldiethanolamine, N,N-diethylhydroxylamine, N-isopropylhydroxylamine, N,N-bisoctadecylhydroxylamine, and N,N-dibenzylhydroxylamine. These polymerization terminators may be used alone or in combination of two or more.
• the amount of the polymerization terminator added is not particularly limited as long as it is an amount sufficient to deactivate the fluorine atom-containing cationic polymerization initiator (A), but it is usually used in a range of 1.0 ⁇ 10 ⁇ 1 to 1.0 ⁇ 10 1 in terms of the molar ratio to the amount of the fluorine atom-containing cationic polymerization initiator (A) added (amount of polymerization terminator added/amount of fluorine atom-containing cationic polymerization initiator (A) added).
• the POM content which is related to the yield of the copolymerization reaction, is preferably 80% or more, more preferably 90% or more, even more preferably 96% or more, particularly preferably 97% or more, and most preferably 97.5% or more.
• the upper limit of the POM content is 100%.
• the "POM content” is measured by the method described in the examples.
• a terminal stabilization step may be included after the polymerization step.
• the terminal stabilization step is a step of stabilizing the terminals of the oxymethylene copolymer.
• the obtained oxymethylene copolymer may have an unstable moiety (-(CH 2 O) n -H) at the terminal.
• the unstable moiety can be depolymerized and converted to a stable terminal (-CH 2 CH 2 OH).
• terminal stabilization is not particularly limited, but it is preferable to melt and heat the oxymethylene copolymer.
• Terminal stabilization is usually performed by melt kneading in an extruder.
• terminal stabilization is preferably performed in the presence of at least one selected from the group consisting of terminal stabilizers, inorganic particles, antioxidants, and scavengers.
• Terminal Stabilizer has the function of improving the decomposition rate of the unstable portion in the oxymethylene copolymer.
• Terminal stabilizers include, but are not limited to, ammonia; amines such as trimethylamine, triethylamine, and tributylamine; hydroxide salts of quaternary ammonium such as tetramethylammonium, tetraethylammonium, ethyltrimethylammonium, trimethyl(2-hydroxyethyl)ammonium, triethyl(2-hydroxyethyl)ammonium, tripropyl(2-hydroxyethyl)ammonium, benzyltrimethylammonium, benzyltriethylammonium, and benzyltripropylammonium; hydrochloride salts (hydrochloride, hydrobromide, etc.); oxoacid salts (sulfate, nitrate, carbonate, etc.); and carboxylate salts (formate, acetate, propionate, benzoate, oxalic acid, etc.). These terminal stabilizers may be
• the terminal stabilizer preferably contains a hydroxide salt of a quaternary ammonium, and more preferably contains at least one of the hydroxide salts of tetramethylammonium, tetraethylammonium, ethyltrimethylammonium, trimethyl(2-hydroxyethyl)ammonium, triethyl(2-hydroxyethyl)ammonium, tripropyl(2-hydroxyethyl)ammonium, benzyltrimethylammonium, benzyltriethylammonium, and benzyltripropylammonium.
• the amount of terminal stabilizer added is preferably 0.01 to 10 parts by mass, and more preferably 0.05 to 5 parts by mass, per 100 parts by mass of oxymethylene copolymer.
• the inorganic particles have a function of improving the thermal stability of the resulting oxymethylene copolymer.
• Inorganic particles are not particularly limited, but examples include talc, mica, wollastonite, silica, layered double hydroxide, calcium carbonate, magnesium hydroxide, calcium hydroxide, etc. These inorganic particles may be used alone or in combination of two or more types.
• the inorganic particles preferably contain at least one selected from the group consisting of talc, mica, and layered double hydroxides, and more preferably contain layered double hydroxides.
• the amount of inorganic particles added is preferably 0.0001 to 1 part by mass, more preferably 0.005 to 0.5 parts by mass, and even more preferably 0.01 to 0.2 parts by mass, per 100 parts by mass of oxymethylene copolymer.
• the antioxidant has the function of preventing the oxidation of the resulting oxymethylene copolymer.
• the antioxidant is not particularly limited, but examples thereof include hindered phenols.
• the hindered phenols include n-octadecyl-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate, n-octadecyl-3-(3'-methyl-5'-t-butyl-4'-hydroxyphenyl)propionate, n-tetradecyl-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate, 1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, t], 1,4-butanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate
• the antioxidant contains triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate].
• the amount of antioxidant added is preferably 0.0001 to 1 part by mass, more preferably 0.001 to 5 parts by mass, and even more preferably 0.003 to 3 parts by mass, per 100 parts by mass of oxymethylene copolymer.
• the scavenger has a function of capturing formic acid and/or formaldehyde generated by decomposition or the like of at least a part of the oxymethylene copolymer.
• the scavengers include, but are not limited to, polyamide resins such as nylon 6, nylon 11, nylon 12, nylon 66, nylon 610, nylon 6T, and nylon 612; amide compounds such as stearyl stearamide, stearyl oleamide, stearyl erucamide, ethylenediamine-distearate amide, and ethylenediamine-dibehenic acid amide; urea compounds such as urea, N-phenyl urea, N,N'-diphenyl urea, N-phenyl thiourea, and N,N'-diphenyl thiourea; and triazine compounds such as melamine, benzoguanamine, N-phenyl melamine, melem, N,N'-diphenyl melamine, N-methylol melamine, N,N'-trimethylol melamine, and 2,4-diamino-6-cyclohexyl triazine.
• the scavenger preferably contains a urea compound and/or a triazine compound, more preferably contains a triazine compound, and even more preferably contains melamine.
• the amount of the scavenger added is preferably 0.0001 to 10 parts by mass, more preferably 0.001 to 5 parts by mass, and even more preferably 0.003 to 3 parts by mass, per 100 parts by mass of the oxymethylene copolymer.
• the temperature for terminal stabilization is not particularly limited, but is preferably 260° C. or less, and more preferably 240° C. or less.
• the lower limit of the temperature for terminal stabilization is not particularly limited as long as it is a temperature equal to or higher than the melting point of the oxymethylene copolymer, but is preferably 150° C. or more, more preferably 180° C. or more, and even more preferably 200° C. or more.
• the temperature for terminal stabilization is preferably 150 to 260° C., more preferably 180 to 260° C., and even more preferably 200 to 240° C.
• the time for terminal stabilization is not particularly limited, but is preferably 1 minute to 3 hours, more preferably 2 minutes to 1 hour, and even more preferably 3 minutes to 30 minutes.
• Terminal stabilization may be performed under reduced pressure.
• the pressure for terminal stabilization is not particularly limited, but is preferably 10 to 100 KPa, more preferably 10 to 80 KPa, and even more preferably 10 to 50 KPa.
• an additive addition step may be included after the polymerization step or the terminal stabilization step.
• the additive addition step is a step of adding an additive to the oxymethylene copolymer.
• the additives are not particularly limited, but may include the above-mentioned stabilizers, inorganic particles, antioxidants, scavengers, as well as colorants, plasticizers, release agents, fluorescent brighteners, antistatic agents, etc.
• the physical properties can be adjusted by adding additives to the oxymethylene copolymer.
• Method for Producing Molded Article there is provided a method for producing a molded article, which comprises molding the oxymethylene copolymer produced by the method described above.
• the oxymethylene copolymer produced by the above-mentioned method has high physical properties, so the molded products made from it also have high physical properties.
• the molded products can be suitably used for high-performance, high-function fibers, films, gears, bearings, etc.
• a cationic polymerization initiator composition was produced by mixing 7.1 mass %, 3 mass %, and 89.9 mass % of boron trifluoride diethyl ether complex ( BF3.Et2O ), which is a fluorine atom-containing cationic polymerization initiator (A), 1,2-dimethoxyethane (DME), which is a hydrophilic ether solvent (B) having neither an acetal structure nor an active hydroxyl group, and benzene, which is another solvent.
• the water content in the cationic polymerization initiator composition was measured with a Karl Fischer moisture meter and found to be 288 ppm.
• Example 2 A cationic polymerization initiator composition was produced in the same manner as in Example 1, except that the content of DME was changed to 25% by mass and the content of benzene was changed to 67.9% by mass.
• the water content in the cationic polymerization initiator composition was measured in the same manner as in Example 1, and was found to be 327 ppm.
• Example 3 A cationic polymerization initiator composition was produced in the same manner as in Example 1, except that the content of DME was changed to 92.9% by mass and the content of benzene was changed to 0% by mass.
• the water content in the cationic polymerization initiator composition was measured in the same manner as in Example 1, and was found to be 332 ppm.
• Example 4 A cationic polymerization initiator composition was prepared in the same manner as in Example 1, except that 1,4-dioxane (DOX) was used instead of DME.
• DOX 1,4-dioxane
• the water content in the cationic polymerization initiator composition was measured in the same manner as in Example 1, and was found to be 326 ppm.
• Example 5 A cationic polymerization initiator composition was produced in the same manner as in Example 4, except that the content of DOX was changed to 25% by mass and the content of benzene was changed to 67.9% by mass.
• the water content in the cationic polymerization initiator composition was measured in the same manner as in Example 1, and was found to be 340 ppm.
• Example 6 A cationic polymerization initiator composition was produced in the same manner as in Example 4, except that the content of DOX was changed to 92.9% by mass and the content of benzene was changed to 0% by mass.
• the water content in the cationic polymerization initiator composition was measured in the same manner as in Example 1, and was found to be 348 ppm.
• Example 7 A cationic polymerization initiator composition was prepared in the same manner as in Example 1, except that tetrahydrofuran (THF) was used instead of DME. The water content in the cationic polymerization initiator composition was measured in the same manner as in Example 1, and was found to be 306 ppm.
• THF tetrahydrofuran
• Example 8 A cationic polymerization initiator composition was produced in the same manner as in Example 7, except that the content of THF was changed to 10% by mass and the content of benzene was changed to 82.9% by mass.
• the water content in the cationic polymerization initiator composition was measured in the same manner as in Example 1, and was found to be 327 ppm.
• Example 9 A cationic polymerization initiator composition was produced in the same manner as in Example 7, except that the content of THF was changed to 25% by mass and the content of benzene was changed to 67.9% by mass.
• the water content in the cationic polymerization initiator composition was measured in the same manner as in Example 1, and was found to be 351 ppm.
• Example 10 A cationic polymerization initiator composition was produced in the same manner as in Example 1, except that tris(pentafluorophenyl)borane trihydrate (TPB.3H 2 O), which is the fluorine atom-containing cationic polymerization initiator (A), was added so as to be 0.3 mass%, and the benzene content was changed to 89.6 mass%.
• TPB.3H 2 O tris(pentafluorophenyl)borane trihydrate
• the water content in the cationic polymerization initiator composition was measured in the same manner as in Example 1, and was found to be 642 ppm.
• Example 11 A cationic polymerization initiator composition was produced in the same manner as in Example 10, except that the content of DME was changed to 10% by mass and the content of benzene was changed to 82.6% by mass.
• the water content in the cationic polymerization initiator composition was measured in the same manner as in Example 1, and was found to be 659 ppm.
• Example 12 A cationic polymerization initiator composition was produced in the same manner as in Example 10, except that the content of DME was changed to 92.6% by mass and the content of benzene was changed to 0% by mass.
• the water content in the cationic polymerization initiator composition was measured in the same manner as in Example 1, and was found to be 662 ppm.
• Example 1 A cationic polymerization initiator composition was prepared in the same manner as in Example 1, except that the content of DME was changed to 0% by mass and the content of benzene was changed to 92.9% by mass. The water content in the cationic polymerization initiator composition was measured in the same manner as in Example 1, and was found to be 276 ppm.
• Example 2 A cationic polymerization initiator composition was produced in the same manner as in Example 1, except that the content of DME was changed to 2.2% by mass and the content of benzene was changed to 90.7% by mass. The water content in the cationic polymerization initiator composition was measured in the same manner as in Example 1, and was found to be 291 ppm.
• Example 3 A cationic polymerization initiator composition was produced in the same manner as in Example 1, except that TPB ⁇ 3H 2 O was added so as to have a concentration of 0.3 mass%, the content of DME was changed to 0 mass%, and the content of benzene was changed to 92.6 mass%.
• the water content in the cationic polymerization initiator composition was measured in the same manner as in Example 1, and was found to be 619 ppm.
• Example 4 A cationic polymerization initiator composition was produced in the same manner as in Example 1, except that TPB ⁇ 3H 2 O was added so as to be 0.3 mass%, the content of DME was changed to 2.2 mass%, and the content of benzene was changed to 90.4 mass%.
• the water content in the cationic polymerization initiator composition was measured in the same manner as in Example 1, and was found to be 595 ppm.
• hydrophilic ether solvents B
• DME dimethoxyethane
• DOX 1,4-dioxane
• THF tetrahydrofuran
• test piece 100 mL of the cationic polymerization initiator composition were placed in a 100 mL screw-cap bottle, sealed, and left to stand in a dark place at 23°C. After 40 days, the test piece was removed from the cationic polymerization initiator composition, washed with acetone, and dried to obtain a "test piece after metal corrosivity test.”
• Weight reduction rate (%) (W1-W2)/(W1) x 100
• W1 is the weight (g) of the "test piece before the metal corrosivity test”
• W2 is the weight (g) of the "test piece after the metal corrosivity test”.
• the metal corrosiveness of the cationic polymerization initiator composition was evaluated according to the following criteria. The obtained results are shown in Table 3 below. ⁇ : Weight loss rate is 0.02% or less ⁇ : Weight loss rate is more than 0.02%
• the cationic polymerization initiator composition from which the test piece was taken out after the metal corrosivity test was separately collected.
• the cationic polymerization initiator composition after the metal corrosivity test is also referred to as the "cationic polymerization initiator composition (after metal corrosivity test).”
• the cationic polymerization initiator composition before the metal corrosivity test is also referred to as the “cationic polymerization initiator composition (before metal corrosivity test).”
• POM content of cationic polymerization initiator composition (before metal corrosivity test) 1,200 g of 1,3,5-trioxane (TOX), 48 g of 1,3-dioxolane as a comonomer, and 300 ppm of methylal as a chain transfer agent relative to 1,3,5-trioxane were charged into a jacketed batch reactor (volume 5 L) that had been heated by passing 65°C hot water through the jacket. The stirring blade was then rotated at 60 rpm, and the cationic polymerization initiator composition (before metal corrosivity test) was injected while stirring and mixing the contents, to initiate the polymerization reaction. 15 minutes after the start of the polymerization reaction, the stirring blade of the batch reactor was stopped, and a crude oxymethylene copolymer was obtained as the reaction product.
• TOX 1,3,5-trioxane
• TOX 1,3-dioxolane as a comonomer
• ppm-TOX means the amount of each component added (ppm) relative to the amount of 1,3,5-trioxane added.
• mmol/mol-TOX means the amount of each component added (mmol) relative to the amount of 1,3,5-trioxane added (1 mol).
• the content (mass %) of the crude oxymethylene copolymer (POM) contained in the coarse-particle crude oxymethylene copolymer was calculated by the following formula.
• POM content (mass%) (B/A) x 100
• A is the mass (g) of the crude oxymethylene copolymer before the removal of the unreacted monomer
• B is the mass (g) of the crude oxymethylene copolymer after the removal of the unreacted monomer.
• POM content was evaluated according to the following criteria. Note that the higher the POM content, the less unreacted monomer there was and the more sufficiently the polymerization reaction proceeded. The results are shown in Table 3 below.
• POM content is less than 96% by mass
• the rate of change was evaluated according to the following criteria. The lower the rate of change (the smaller the negative value), the less the metal components dissolved in the cationic polymerization initiator composition by the metal corrosivity test inhibited the polymerization reaction. The results are shown in Table 3 below. ⁇ : -0.2% or more ⁇ : -0.5% or more but less than -0.2% ⁇ : -0.8% or more but less than -0.5% ⁇ : Less than -0.8%
• MFR Melt Mass Flow Rate
• the fluorine atom-containing cationic polymerization initiator (A) was deactivated and terminal stabilized as follows.
• the MFR (g/10 min) of the end-stabilized oxymethylene copolymer was measured according to ASTM-D1238 (190°C, 2.16 kg load).
• MFR was evaluated according to the following criteria. The smaller the MFR, the higher the molecular weight. The results are shown in Table 3 below.
• MFR is more than 6.1 g/10 min and less than 6.2 g/10 min.
• ⁇ : MFR is more than 6.2 g/10 min and less than 7.0 g/10 min.
• MFR is more than 7.0 g/10 min.
• Rate of change (%) (MFR after metal corrosion test - MFR before metal corrosion test) / (MFR before metal corrosion test) x 100
• the rate of change was evaluated according to the following criteria. The lower the rate of change (the smaller the positive value), the less the metal components dissolved in the cationic polymerization initiator composition by the metal corrosivity test inhibited the polymerization reaction. The results are shown in Table 3 below. ⁇ : 3% or less ⁇ : More than 3% and less than 5% ⁇ : More than 5% and less than 7% ⁇ : More than 7%
• the results in Table 3 show that the cationic polymerization initiator compositions of Examples 1 to 12 were able to prevent metal corrosion.
• the low rate of change in POM content indicates that the prevention of metal corrosion made it possible to suppress the elution of metal components and inhibit the inhibition of the polymerization reaction.
• the low rate of change in MFR indicates that the deterioration of the physical properties of the resulting oxymethylene copolymer was inhibited.

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