JPS6153366B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a polyacetal copolymer, and more particularly, to a method for copolymerizing formaldehyde and alkylene oxide or polyalkylene oxide in the coexistence of an anionic polymerization catalyst and a Lewis acid. . Japanese Patent Publication No. 42-15632 describes the copolymerization of formaldehyde or trioxane and 1,4-butanediol formal using a catalyst mainly containing boron trifluoride. British Patent No. 911960 describes the copolymerization of formaldehyde and alkylene oxide using a Friedel-Crafts catalyst. Further, Japanese Patent Publication No. 48-3558 describes the copolymerization of formaldehyde and cyclic ether using a reaction mixture of a polyvalent metal chelate compound and a Lewis acid. The catalysts found in these publications are essentially Lewis acids, and the production of formaldehyde copolymers using these catalysts has the disadvantage that side reactions occur frequently and the molecular weight of the copolymers decreases. Industrially, it is necessary to produce a polyacetal copolymer with a predetermined molecular weight by using a so-called molecular weight regulator, but in these methods, it is impossible to use a molecular weight regulator, These methods are not necessarily suitable industrial methods. Japanese Patent Publication No. 40-1951 describes that formaldehyde and an oxirane compound are copolymerized using an anionic polymerization catalyst such as an amine. In a copolymerization reaction using an anionic polymerization catalyst, only formaldehyde homopolymers and oxirane compound homopolymers are produced, and almost no copolymers can be obtained. Even if a copolymer is produced in a very small proportion, this copolymer is a block copolymer of polyoxymethylene and a polyoxolane compound, and has low practical value as a polyacetal copolymer. As mentioned above, whether Lewis acid alone or anionic polymerization catalyst alone is used in engineering
It is difficult to obtain polyacetal copolymers that have properties as plastics. As a result of extensive studies on the method for producing polyacetal copolymers, the present inventors discovered that formaldehyde and alkylene oxide or polyalkylene oxide are combined in the coexistence of an anionic polymerization catalyst excluding a polyvalent metal chelate compound and a Lewis acid. The present inventors have discovered that, by copolymerization, a polyacetal copolymer having both the desired molecular weight and good thermal and base stability can be obtained in high yield, leading to the completion of the present invention. That is, an object of the present invention is to provide a method for producing a polyacetal copolymer having a desired molecular weight and excellent physical properties by introducing an oxyalkylene bond into a polyoxymethylene main chain. The first comonomer that can be used in the present invention has the general formula

[Formula] (R = selected from hydrogen, alkyl group, substituted alkyl group, aryl group, substituted aryl group, each of which may be the same or different. m = 2 to 6) There is an alkylene oxide. For example, ethylene oxide, propylene oxide, butylene oxide,
trans-2,3-epoxybutane, cis-2,3-
Epoxybutane, isobutylene oxide, oxetane, 3,3-bis(chloromethyl)oxetane, tetrahydrofuran, 2-methyltetrahydrofuran, oxepane, styrene oxide, p-
Chlorstyrene oxide, epichlorohydrin,
Examples include cyclohexene oxide. Among these alkylene oxides, ethylene oxide, propylene oxide, butylene oxide, styrene oxide, and cyclohexene oxide are particularly preferred. The second comonomer that can be used in the present invention has the general formula

[Formula] (R = selected from hydrogen, alkyl group, substituted alkyl group, aryl group, and substituted aryl group, each of which may be the same or different. m = 2 to 6, n = 3 to 20000) There is a polyalkylene oxide having the structure represented by: Polyalkylene oxides are usually the corresponding alkylene oxides

Obtained by ring-opening polymerization of [Formula]. As ring-opening polymerization catalysts, cationic polymerization catalysts, anionic polymerization catalysts, coordination anionic polymerization catalysts, and the like are known. The first group of polyalkylene oxides includes polyethylene oxide, which is a ring-opened polymer of ethylene oxide, and polyethylene oxide derivatives. For example, polyethylene glycol (average molecular weight 1500), polyethylene glycol diacetate (average molecular weight 10000), polyethylene glycol dimethyl ether (average molecular weight 15000), polyethylene glycol p-nonylphenyl ether (average molecular weight 2350), glycerin ethylene oxide adduct (average molecular weight 5200) ), trimethylolpropane ethylene oxide adduct (average molecular weight 920),
Sorbitan monolaurate ethylene oxide adduct (average molecular weight 2350), pentaerythritol ethylene oxide adduct (average molecular weight 3400), polyethylene oxide (PEO, average molecular weight 50000) polyethylene oxide (PEO, average molecular weight
400000) etc. are included in this group. The second group of polyalkylene oxides includes polypropylene oxide, which is a ring-opened polymer of propylene oxide, and polypropylene oxide derivatives. For example, polypropylene glycol (average molecular weight 7500), polypropylene glycol monolaurate (average molecular weight 15000), polypropylene glycol dimethyl ether (average molecular weight
6000), trimethylolpropane propylene oxide adduct (average molecular weight 7150), pentaerythritol propylene oxide adduct (average molecular weight
1150), polypropylene oxide (PPO, average molecular weight 100,000), etc. are included in this group. The third group of polyalkylene oxides includes polybutylene oxide, which is a ring-opened polymer of butylene oxide, and polybutylene oxide derivatives. For example, polybutylene glycol (average molecular weight 2000), polybutylene glycol dipropionate (average molecular weight 4300), polybutylene glycol dimethyl ether (average molecular weight 1000), etc. are included in this group. The fourth group of polyalkylene oxides includes oxetane, polytrimethylene oxide, which is a ring-opening polymer of substituted oxetane, and trimethylene oxide derivatives. For example, trimethylene glycol (average molecular weight 450), trimethylene glycol dimethyl ether (average molecular weight 610), 3.3
- Ring-opened polymers of bis(chloromethyl)oxetane are included in this group. A fifth group of polyalkylene oxides includes tetrahydrofuran, polytetramethylene oxide, which is a ring-opened polymer of substituted tetrahydrofuran. For example, polytetramethylene glycol (average molecular weight 1250), polytetramethylene glycol dimethyl ether (average molecular weight 1750), etc. are included in this group. The sixth group of polyalkylene oxides includes oxepane, polyhexamethylene oxide, which is a ring-opened polymer of substituted oxepane. For example, polyhexamethylene glycol (average molecular weight
850), polyhexamethylene glycol dimethyl ether (average molecular weight 650), etc. are included in this group. The seventh group of polyalkylene oxides includes styrene oxide, polystyrene oxide, which is a ring-opening polymer of substituted styrene oxide, and polystyrene oxide derivatives. For example, polystyrene glycol (average molecular weight 1850), polystyrene glycol dimethyl ether (average molecular weight
4500), poly p-chlorostyrene glycol (average molecular weight 2750), etc. are included in this group. In addition to the above seven groups, polyalkylene oxides obtained by ring-opening polymerization of alkylene oxides other than the above-mentioned compounds are also effective. For example, a polymer obtained by ring-opening polymerization of epichlorohydrin, a polymer obtained by ring-opening polymerization of trans-2,3-epoxybutane, etc. can also be used in the present invention. Among these polyalkylene oxides, polyethylene oxide, polyethylene oxide derivatives, polypropylene oxide, and polypropylene oxide derivatives are particularly preferred. In addition, the average degree of polymerization (n) of polyalkylene oxide must be between 3 and 20,000,
The lower limit of the average degree of polymerization is more preferably 10 or more from the viewpoint of avoiding chain transfer reactions during the copolymerization reaction as much as possible, and the upper limit of the average degree of polymerization is more preferably 10,000 or less from the viewpoint of ease of synthesis. . For example, glycerin ethylene oxide adduct When _one molecule contains multiple polyalkylene oxide chains _, as _in
It needs to be between 20,000 and even 10~
It is more preferable that it be between 10,000. These alkylene oxides and polyalkylene oxides are used alone or in combination for the reaction. Further, prior to the reaction, it is preferable to purify the alkylene oxide or polyalkylene oxide by removing impurities such as water contained in the alkylene oxide or polyalkylene oxide as much as possible. The anionic polymerization catalyst that can be used in the present invention generally has formaldehyde homopolymerization activity and excludes polyvalent metal chelate compounds. These anionic polymerization catalysts include:
Alkali metals, alkali metal complex compounds, alkali metal alkoxides, alkali metal carboxylic acids,
Examples include alkaline earth metal carboxylic acid salts, amines, quaternary ammonium salts, quaternary phosphonium salts, organic metals, and tetravalent organic tin compounds. Alkali metals include sodium, potassium, etc., and are usually used after being dispersed in an organic medium. Examples of the alkali metal complex compounds include complex compounds of alkali metals and aromatic hydrocarbons, such as sodium-naphthalene and potassium-anthracene. The alkali metal alkoxide is ROM (R=C ₁
~ _C10 linear/branched alkyl group, M=alkali metal), and examples include sodium methoxide, potassium t-butoxide, and potassium octoxide. The alkali metal carboxylic acid salt is RCOOM (R=
It is a compound represented by a _C5 to _C20 linear or branched alkyl group (M=alkali metal), and examples include sodium caproate, potassium laurate, and cesium stearate. Carboxylic acid alkaline earth metal salts are
(RCOO) is a compound represented by ₂ M' (R= _C5 to _C20 linear/branched alkyl group, M'=alkaline earth metal), and includes magnesium 2-ethylhexanoate, calcium laurate, calcium stearate, Examples include strontium stearate. Examples of amines include primary amines represented by RNH ₂ (R is a C ₁ to C ₂₀ linear/branched alkyl group);
R ₂ NH (R is a C ₁ to C ₂₀ linear/branched alkyl group)
and tertiary amines represented by R ₃ N (R is a C ₁ to C ₂₀ linear or branched alkyl group). For example, ethylamine, n-butylamine, octylamine, stearylamine, di-n-propylamine, di-t-butylamine,
distearylamine, triethylamine, tri-
Examples include n-butylamine, trioctylamine, diethylbenzylamine, and the like. Further, cyclic amines such as pyridine can also be used. Quaternary ammonium salt is NH ₄ X or
R ₁ R ₂ R ₃ R ₄ NX (R ₁ , R ₂ , R ₃ , R ₄ = selected from hydrogen, alkyl group, substituted alkyl group, aryl group, substituted aryl group, and there are no restrictions on the combination. X =
It is a compound represented by an anion obtained by removing hydrogen ions from a Lewis acid having a dissociation constant of 1 x 10 ^-2 to 1 x 10 ^-16 in water at 25°C. For example, ammonium laurate, ammonium stearate, tetramethylammonium propionate, tetrabutylammonium caproate, trioctylbenzylammonium acetate, dimethyldistearylammonium propionate, diethylbenzylammonium laurate, tetramethylammonium methoxide, trimethyl Benzyl ammonium propoxide, triphenylmethyl ammonium butoxide, tetrabutylammonium hydroxide, dimethyl distearyl ammonium hydroxide, tetraethylammonium carboxylate, etc. are the fourth
It is listed as a class ammonium salt. The quaternary phosphonium salt is R ₁ R ₂ R ₃ R ₄ PX (R ₁ ,
R ₂ , R ₃ , R ₄ = selected from hydrogen, an alkyl group, a substituted alkyl group, an aryl group, and a substituted aryl group, and the combination thereof is not limited. X=25℃, 1× in water
It is a compound represented by an anion obtained by removing hydrogen ions from a Lewis acid having a dissociation constant of 10 ^-2 to 1 x 10 ^-16 . For example, tetraethylphosphonium propionate, tetrabutylphosphonium acetate, tetraoctylphosphonium caproate, triphenylmethylphosphonium propionate, tetrabutylphosphonium ethoxide, triethylbenzylphosphonium butoxide, tetraoctylphosphonium hydroxide, tetraethylphosphonium carboxylate, etc. It is listed as a quaternary phosphonium salt. The first group of organometallics is RM (R=C ₁ ~
It is a compound represented by _C10 straight chain/branched alkyl group, M=alkali metal) or _R2M ' (R= _C1 to _C10 straight chain/branched alkyl group, M'=alkaline earth metal). , methyllithium, n-butyllithium, ethyl sodium, sec-butylpotassium, diethylcalcium, dioctylstrontium, and the like. The second group of organometallics is RMgX′ (R=
It is a compound represented by a C ₁ to C ₈ linear or branched alkyl group, X' = halogen), and examples thereof include methylmagnesium chloride, ethylmagnesium bromide, butylmagnesium iodide, and the like. The tetravalent organic tin compound is a compound represented by R _1n SnX _4-n . Here, n = an integer of 1 to 3, and R ₁ = selected from an alkyl group, a substituted alkyl group, an aryl group, and a substituted aryl group, each of which may be the same or different. X = halogen, -
OH, −OR ₂ ,

[Formula] (R ₂ = C ₁ to C ₂₀ linear/branched alkyl group). For example, methyltin trichloride, ethyltin triacetate,
Examples include butyltin trimethoxide, methyltin dibromide, diisopropyltin dilaurate, dioctyltin dibutoxide, dibutyltin hydroxystearate, dioctyltin dilaurate, triethyltin ethoxide, and tributyltin stearate. The Lewis acids used in the present invention include:
Tin tetrachloride, tin tetrabromide, titanium tetrachloride, aluminum trichloride, zinc chloride, vanadium trichloride, antimony pentafluoride, boron trifluoride, boron trifluoride diethyl etherate, boron trifluoride acetic anhide so-called Friedel-Crafts type compounds such as boron trifluoride coordination compounds such as boron trifluoride triethylamine complex, inorganic acids such as perchloric acid, acetyl perchlorate, hydroxyacetic acid, trichloroacetic acid, and p-toluenesulfonic acid. and organic acids, complex salt compounds such as triethyloxonium tetrafluoroborate, triphenylmethylhexafluoroantimonate, allyldiazonium hexafluorophosphate, allyldiazonium tetrafluoroborate, alkyl metals such as diethylzinc, triethylaluminum, diethylaluminum chloride, etc. etc. can be mentioned. Among these Lewis acids, Friedel-Crafts type compounds and complex salt compounds are more preferred in terms of activity, but inorganic acids, organic acids, and alkyl metals can also be combined with Friedel-Crafts type compounds by increasing the amount added. It can bring about the same effect as salt compounds. In the present invention, the molecular weight of the polyacetal copolymer can also be arbitrarily adjusted using a molecular weight regulator. Molecular weight modifiers that can be used in the present invention include acetal compounds, orthoformates, alcohols, carboxylic acids, carboxylic acid anhydrides, and water. As the first group of acetal compounds,
ROCH ₂ OR (R = alkyl group), HOCH ₂ OR (R
= a formal compound represented by (alkyl group),
There are hemiformal compounds. Specific examples include methylal, diethoxymethane, di-n-butoxymethane, butoxyhydroxymethane, and the like. The second group of acetal compounds includes RO( _CH2O )nR (R=alkyl group, n=2
There are polyacetal compounds represented by ~20). Specifically, dioxymethylene dimethoxide,
Examples include tetraoxymethylene diethoxide and decaoxymethylene dimethoxide. These compounds are often difficult to isolate as single substances and are usually used as a mixture. The degree of polymerization (n) of these compounds can be determined by nuclear magnetic resonance spectroscopy (NMR), gas chromatography (GC).
), liquid chromatography (LC), and other methods. As a third group of acetal compounds

There is an acetal compound represented by the formula (R=alkyl group). Specific examples include dimethyl acetal, diethyl acetal, di-t-butyl acetal, dioctyl acetal, and the like. Orthoformic acid ester is HC(OR) ₃ (R=C ₁ ~
It is a compound represented by _C4 straight chain/branched alkyl group and phenyl group), such as methyl orthoformate, ethyl orthoformate, -iso-propyl orthoformate,
Examples include diethylpropyl orthoformate, butyl orthoformate, and phenyl orthoformate. Alcohol is a compound represented by ROH (R=C ₁ to C ₂₀ linear/branched alkyl group, aryl group), and includes fatty acids such as methanol, ethanol, n-propanol, n-butanol, lauryl alcohol, and stearyl alcohol. Examples include aromatic alcohols such as group alcohols, benzyl alcohol, and 2-phenylethanol. Carboxylic acids are RCOOH (R = hydrogen, C ₁ - C ₂₀
It is a compound represented by linear/branched alkyl groups, aryl groups), and is a compound represented by formic acid, acetic acid, propionic acid,
Examples include aliphatic carboxylic acids such as lauric acid and stearic acid, and aromatic carboxylic acids such as benzoic acid and iso-phthalic acid. Carboxylic acid anhydride is

【formula】

【formula】

【formula】

[Formula] (R ₁ = C ₁ to C ₂₀ alkyl group, R ₂ = hydrogen or C ₁ to C ₂₀
alkyl group, R ₃ = hydrogen or C ₁ to C ₈ alkyl group), acetic anhydride,
Aliphatic carboxylic anhydrides such as propionic anhydride, stearic anhydride, succinic anhydride, dodecenylsuccinic anhydride, maleic anhydride, phthalic anhydride, 4
-Aromatic carboxylic acid anhydrides such as methyl phthalic anhydride. Among these molecular weight regulators, from the viewpoint of improving the thermal stability and base stability of the polymer,
Formal compound represented by ROCH ₂ OR, RO
Polyacetal compounds represented by (CH ₂ O) nR and

An acetal compound represented by the formula is preferred, and methylal and diethyl acetal are particularly preferred from the viewpoint of ease of purification and availability. The copolymerization according to the invention is usually carried out in an organic medium. Organic media that can be used in the present invention include aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, n-octane, cyclohexane, and cyclopentane, benzene, toluene,
Aromatic hydrocarbons such as xylene, halogenated aliphatic hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride, ethylene chloride, trichloroethylene, halogenated aromatics such as chlorobenzene, o-dichlorobenzene, α-chloronaphthalene, etc. Examples include hydrocarbons. These organic media may be used alone or in combination of two or more. The formaldehyde used in the present invention must be substantially anhydrous and must be purified using a known method, such as a cold trap method or a solvent washing method. For producing the polyacetal copolymer of the present invention,
As a method for homopolymerizing formaldehyde, both the blow polymerization method and the solution polymerization method can be used. The blow polymerization method is a method in which formaldehyde gas is directly blown into an organic medium containing an alkylene oxide or polyalkylene oxide, a molecular weight modifier when a molecular weight modifier is used, a nonionic polymerization catalyst, and a Lewis acid. Legal means that alkylene oxide or polyalkylene oxide, or when using a molecular weight modifier, cool the organic medium containing the molecular weight modifier, allow this solution to absorb formaldehyde, and then simultaneously add an anionic polymerization catalyst and a Lewis acid. This is a method in which the copolymerization is started by adding the copolymer. The alkylene oxide is preferably 0.01 to 100 mol% based on 1 mol of formaldehyde, more preferably,
It is used in a range of 0.1 to 50 mol%. The polyalkylene oxide is 0.01 to 100 parts by weight, more preferably 0.1 to 50 parts by weight, based on 100 parts by weight of formaldehyde.
Parts by weight are used. The anionic polymerization catalyst has a concentration in the organic medium of 1×10 ⁻⁸ to 1×10 ⁻² mol/, more preferably,
It is used in a range of 5×10 ⁻⁸ to 5×10 ⁻³ mol/. Also, the Lewis acid has a concentration of 1 in an organic medium.
×10 ^-7 to 5 × 10 ^-2 mol/, more preferably 1 ×
It is used in a range of 10 ^-5 to 5 x 10 ^-3 mol/. It is desirable that the anionic polymerization catalyst and the Lewis acid are separately supplied into an organic medium and then mixed in the organic medium. It is truly a surprising phenomenon that even when an anionic polymerization catalyst and a Lewis acid coexist in an organic medium, they do not become deactivated and exhibit copolymerization activity. The copolymerization reaction temperature is usually set at -40 to 118°C. Further, there is no particular restriction on the reaction time, but it is set within a range of 5 to 400 minutes. When using a molecular weight regulator, the molecular weight regulator is used after being uniformly dissolved or dispersed in an organic medium, like alkylene oxide and polyalkylene oxide. The concentration of the molecular weight modifier in the organic medium can be easily determined experimentally depending on the molecular weight requirements of the desired copolymer. After the copolymerization reaction is completed, the copolymer is usually separated from the organic medium, and water and alcohol are added together with a basic substance such as an amine and sodium hydroxide, followed by heating and stabilization. A stabilizer and the like are then added to the stabilized copolymer, and the copolymer is put into practical use. By using the production method of the present invention described in detail above, it has become possible to obtain a good polyacetal copolymer. The features of the present invention are listed below. (1) It is possible to produce polyacetal copolymers with excellent thermal stability and base stability. (2) The molecular weight of the polyacetal copolymer can be controlled arbitrarily by using a molecular weight regulator. (3) By using a specific molecular weight regulator, it is possible to simultaneously adjust the molecular weight and improve the thermal stability and base stability of the polymer. In the following description, reduced viscosity is a value measured at 60°C in a p-chlorophenol-tetrachlorethylene (1:1 weight ratio) solution at a polymer concentration of 0.5 gr./dl, and is It is a measure. The base stabilization yield is the recovery rate of the polymer when heated at 140°C for 60 minutes at a polymer concentration of 5% in a benzyl alcohol solution containing 1% tributylamine. It is a measure of gender. K ₂₂₂ is the thermal decomposition rate constant of a polymer under vacuum at 222°C and is a measure of the thermal stability of a polymer. The present invention will be explained below with reference to Examples, but these are not intended to limit the scope of the present invention. Example 1 Sufficiently dehydrated and dried paraformaldehyde
Formaldehyde gas with a purity of 99.9% was obtained by thermal decomposition at a temperature range of 135°C to 145°C and passing through a cooling trap several times. 125 parts of formaldehyde gas per hour, 15 gr./propylene oxide, 1.0×10 ^-4 mol/n-butyllithium,
It was introduced into 500 parts of n-hexane containing 1×10 ^-4 mol/of boron trifluoride diethyl etherate and 0.09 gr.// of methylal as molecular weight regulator. 15g at the same time as formaldehyde gas supply
r. of propylene oxide, 1.0×10 ^-4 mol/n-butyllithium, 1.0×10 ^-4 mol/boron trifluoride diethyl etherate, 0.09 gr./n-hexane containing methylal for 1 hour. Hit
It was fed continuously for 3 hours at a rate of 500 parts. Formaldehyde gas was also continuously supplied at a rate of 125 parts per hour for 3 hours, during which time the copolymerization temperature was maintained at 55°C. N-hexane containing the copolymer was continuously extracted in proportion to the amount supplied, and the copolymer was separated by filtration. After thoroughly washing the copolymer with acetone,
Vacuum drying was performed at 60°C to obtain 354 parts of a white polymer. This polymer had a reduced viscosity of 1.98 and a base stabilization yield of 97.2%. In addition, the polymer after base stabilization
K ₂₂₂ was good at 0.03%/min, and a polymer having the desired molecular weight with excellent thermal stability and base stability could be obtained in high yield. Examples 2 to 12 Formaldehyde gas with a purity of 99.9% at a rate of 100 parts per hour in 500 parts of toluene containing an alkylene oxide or polyalkylene oxide shown in Table 1, an anionic polymerization catalyst, a Lewis acid and a molecular weight modifier. was continuously supplied for 3 hours. 1st
Toluene containing the alkylene oxide or polyalkylene oxide, anionic polymerization catalyst, Lewis acid, and molecular weight regulator shown in the table was also supplied continuously at a rate of 500 parts/hr for 3 hours, like the formaldehyde gas, and the copolymerization temperature was kept at a constant rate during this period. The temperature shown in Table 1 was maintained. After separating the copolymer from toluene, the same procedure as in Example 1 was carried out, and the results are also shown in Table 1. It is clear that in all Examples, copolymers with excellent thermal stability and base stability and with desired molecular weights were obtained in high yields. Comparative Example 1 Among the reagents used in Example 1, only n-butyllithium was excluded, and all other operations were performed in the same manner as in Example 1, and the results are shown in Table 1. As is clear from Table 1, only a polymer with low reduced viscosity and poor thermal stability was obtained. Comparative Example 2 Among the reagents used in Example 1, only boron trifluoride diethyl etherate was excluded, and all others were operated in the same manner as in Example 1, and the results are shown in Table 1.
As is clear from Table 1, only a polymer with an extremely low base-stabilized yield was obtained.

【table】

【table】

Claims (1)

[Claims] 1. Formaldehyde and the general formula [Formula] (R = hydrogen, alkyl group, substituted alkyl group, aryl group, substituted aryl group, each of which may be the same or different). m
= 2 to 6) and the general formula [Formula] (R = hydrogen, alkyl group, substituted alkyl group, aryl group, substituted aryl group, each of which may be the same or different) . m = 2 to 6, n = 3 to 20000) in the coexistence of an anionic polymerization catalyst excluding a polyvalent metal chelate compound and a Lewis acid. A method for producing a polyacetal copolymer, characterized by copolymerizing the polyacetal copolymer. 2 Alkylene oxide is ethylene oxide,
Claim 1 is a compound selected from the group consisting of propylene oxide, butylene oxide, styrene oxide and cyclohexene oxide.
Manufacturing method described in section. 3. The production method according to claim 1, wherein the polyalkylene oxide is a compound selected from the group consisting of polyethylene oxide, polyethylene oxide derivatives, polypropylene oxide, and polypropylene oxide derivatives. 4 Average degree of polymerization of polyalkylene oxide (n)
is between 10 and 10,000. 5. The production method according to claim 1, in which a molecular weight regulator is present during the copolymerization reaction. 6 The molecular weight regulator has the general formula ROCH ₂ OR (R = alkyl group), RO (CH ₂ O) _o R (R = alkyl group, n
2-20) and acetal compounds represented by the formula (R=alkyl group). 7. The production method according to claim 6, wherein the acetal compound is methylal or diethyl acetal.