JPH11279245A - Production of polyacetal resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for industrially and stably producing a polyacetal resin for a long period. SOLUTION: This production for a polyacetal resin is conducted by block- polymerizing (A) trioxane, (B) a cyclic ether and/or cyclic formal and (C) a monoglycidyl ether compound by using (D) a cation polymerization catalyst, wherein the block polymerization is performed by adding a mixture of (B) the cyclic ether and/or cyclic formal, (C) the monoglycidyl ether compound and (D) a cation polymerization catalyst to (A) trioxane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyacetal resin, and more particularly, to a method for producing a stable polyacetal resin by eliminating a difference in molecular weight distribution between pellets.

[0002]

2. Description of the Related Art Polyacetal resins are well-balanced in mechanical properties, chemical resistance, slidability and the like, and are easy to process. Widely used mainly for parts and other various mechanical parts. Polyacetal resin is generally provided industrially as pellets (granules) by once melting and kneading the crude polyacetal resin flakes discharged from the polymerization machine,
Even when the same manufacturing apparatus is used and the same manufacturing method is used, each particle of polyacetal resin pellets is
It cannot necessarily be said that each has the same molecular weight distribution. The difference in molecular weight distribution between the pellets is
Even if the pellets are melted and kneaded by an extruder, a molding machine or the like, it cannot be said that the pellets are completely eliminated, so that sufficient attention is paid to quality control of the polyacetal resin product.

[0003] The difference in molecular weight distribution generated between such pellets can be attributed to the injection moldability, extrusion moldability, and polyacetal resin.
It is not generally preferable because it has an adverse effect on melt processability such as blow moldability, and may also form fine foreign matters on the surface of the molded product, resulting in poor surface appearance. In order to eliminate the difference in molecular weight distribution generated between pellets and to produce a polyacetal resin having a stable quality, as described above, conventionally, a method of strengthening melt kneading in an extruder, a molding machine or the like has been used. However, from the viewpoint of quality control, there is a strong demand for a fundamental improvement method particularly from the viewpoint of polymerization.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a polyacetal resin having a stable quality by eliminating the difference in molecular weight distribution generated between pellets in view of the above situation.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have once mixed a cyclic ether and / or cyclic formal, a monoglycidyl ether compound and a cationic polymerization catalyst, and The mixture
The inventors have found that the above-mentioned problems can be solved by adding and supplying to trioxane for polymerization, and have completed the present invention.

That is, a first aspect of the present invention is to polymerize (A) trioxane, (B) cyclic ether and / or cyclic formal, and (C) monoglycidyl ether compound in bulk using (D) a cationic polymerization catalyst to form a polyacetal. In the method for producing a resin, a mixture obtained by mixing (B) a cyclic ether and / or cyclic formal, (C) a monoglycidyl ether compound, and (D) a cationic polymerization catalyst is added to (A) trioxane and polymerized. And a method for producing a polyacetal resin. A second aspect of the present invention is that a mixture obtained by previously mixing (B) a cyclic ether and / or cyclic formal and (C) a monoglycidyl ether compound, and further mixing (D) a cationic polymerization catalyst with (A) trioxane The present invention also relates to the method for producing a polyacetal resin according to the first aspect of the present invention, which comprises adding, supplying, and polymerizing the polyacetal resin. A third aspect of the present invention is that a mixture obtained by mixing (B) a cyclic ether and / or cyclic formal and (D) a cationic polymerization catalyst in advance, and further mixing (C) a monoglycidyl ether compound with the (A) trioxane The first aspect of the present invention, characterized in that it is added and supplied to the
The present invention relates to a method for producing a polyacetal resin. A fourth aspect of the present invention is that the cationic polymerization catalyst (D) is at least one selected from the group consisting of boron trifluoride and a boron trifluoride coordination compound.
3. A method for producing a polyacetal resin according to any one of (1) to (3). A fifth aspect of the present invention is that (B) a cyclic ether and / or
Or cyclic formal is ethylene oxide, 1,3-dioxolan, diethylene glycol formal, 1,4
-At least one member selected from the group consisting of -butanediol formal;
The present invention relates to a method for producing a polyacetal resin according to any one of the above. A sixth aspect of the present invention is that the (C) monoglycidyl ether compound is at least one selected from the group consisting of compounds represented by the following general formula (1). 5. A method for producing a polyacetal resin according to any one of (5) to (5).

[0007]

Embedded image

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for producing a polyacetal resin of the present invention will be described. The polyacetal resin of the present invention is obtained by subjecting (A) trioxane, (B) cyclic ether and / or cyclic formal, and (C) monoglycidyl ether compound to bulk polymerization using (D) a cationic polymerization catalyst, The main component is a copolymer of polyacetal resin. The basic molecular structure is not particularly limited, and includes those having a branched / crosslinked structure, those having a block component introduced, and the like. Further, the molecular weight or the melt viscosity is not limited to these as long as it can be melt-molded. If specified,
Melt index is 0.1-100g / 10min
(According to ASTM D1238) is preferred. If the melt index is more than 100 g / 10 min, the mechanical substance is remarkably reduced. If the melt index is less than 0.1 g / 10 min, the fluidity of the resin becomes poor, which is not preferable.

Examples of the cyclic ether and / or cyclic formal (B) used in the present invention include ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, epibromohydrin, styrene oxide,
Oxetane, 3,3-bis (chloromethyl) oxetane, cyclic ethers such as tetrahydrofuran, ethylene glycol formal, propylene glycol formal, diethylene glycol formal, triethylene glycol formal, 1,4-butanediol formal, 1,5-pentanediol formal, 1,6-hexanediol formal, trioxepane, 1,3-
Cyclic formals such as dioxolane, and mixtures thereof. Among them, ethylene oxide, 1,3
-Dioxolane, diethylene glycol formal,
1,4-butanediol formal or a mixture thereof is preferred.

The amount of the cyclic ether and / or cyclic formal (B) to be used is 0.1 or more in total with respect to (A) trioxane in consideration of the rigidity and chemical resistance of the molded article. 1 to 20% by weight, preferably 0.5 to
15% by weight. (B) When the amount of the cyclic ether and / or cyclic formal exceeds 20% by weight, the mechanical strength such as the rigidity of the molded product and the chemical resistance are reduced, and 0.1% or less.
If it is less than 1%, the thermal stability of the resin is undesirably reduced. Further, the cyclic ether and / or cyclic formal may be used after previously diluted with another organic solvent or the like.

The monoglycidyl ether compound (C) of the present invention is exemplified by the compound represented by the above general formula (1). In the present invention, as long as the monoglycidyl ether compound (C) has one glycidyl ether group in its molecular structure, it is not limited to the above examples, and all conventionally known compounds can be used. Specific compounds include methyl glycidyl ether, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, octyl glycidyl ether,
Decyl glycidyl ether, stearyl glycidyl ether, ethoxybutyl glycidyl ether, 1-allyloxy-2,3-epoxypropane, 1- (1 ', 1'-dimethylpropargyloxy) -2,3-epoxypropane, phenylglycidyl ether, tolyl Glycidyl ether, butylphenyl glycidyl ether, naphthyl glycidyl ether, 3- (2-xenyloxy) -1,2-epoxypropane and the like are exemplified. The amount of the monoglycidyl ether compound (C) to be used is preferably 0.001 to 10% by weight in total of trioxane by one or more kinds in consideration of rigidity, chemical resistance and the like of the molded article. And particularly preferably 0.01 to 5% by weight. Also, (C)
The monoglycidyl ether compound may be previously diluted with another organic solvent.

In the production method of the present invention, in addition to the above components, other chemical components such as a component for controlling the molecular weight and a component capable of forming a branched / crosslinked structure can be used in combination. As a component for adjusting the molecular weight, a chain transfer agent that does not form an unstable terminal, for example, an alkoxy group such as methylal, methoxymethylal, dimethoxymethylal, trimethoxymethylal, and oxymethylene di-n-butyl ether. Low molecular weight acetal compounds, and one or more of these are used. Further, the amount of use is preferably 0.001 to 1 in total or approximately 2 or more types based on trioxane.
0.5% by weight.

The components capable of forming a branched / crosslinked structure include, for example, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether,
1,4-butanediol diglycidyl ether, hexamethylene glycol diglycidyl ether, resorcinol diglycidyl ether, bisphenol A diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polybutylene glycol diglycidyl ether, glycerin and Derivatives such as the alkylene oxide adduct or glycidyl ether thereof, and pentaerythritol and derivatives thereof such as the alkylene oxide adduct or glycidyl ether are exemplified. The amount used is 0.3% by weight or less, preferably 0.2% by weight based on trioxane.
It is as follows.

These components capable of forming a branched / crosslinked structure may be added to (A) trioxane or (B)
Cyclic ether and / or cyclic formal, or (C)
It may be added to the monoglycidyl ether compound, or may be added by diluting in advance with another organic solvent or the like.

The (D) cationic polymerization catalyst used in the present invention includes lead tetrachloride, tin tetrachloride, titanium tetrachloride, aluminum trichloride, zinc chloride, vanadium trichloride, antimony trichloride, phosphorus pentafluoride, Antimony fluoride, boron trifluoride, boron trifluoride diethyl etherate, boron trifluoride dibutyl etherate, boron trifluoride dioxanate, boron trifluoride acetic unhydrate, boron trifluoride triethylamine complex compound Boron fluoride coordination compound, perchloric acid, acetyl perchlorate, t-butyl perchlorate, hydroxyacetic acid, trichloroacetic acid, trifluoroacetic acid, inorganic and organic acids such as p-toluenesulfonic acid, triethyloxonium tetrafluoroborate, Triphenylmethylhexafluoroantimonate, Complex salt compounds such as rildiazonium hexafluorophosphate and allyldiazonium tetrafluoroborate; alkyl metal salts such as diethyl zinc, triethyl aluminum and diethyl aluminum chloride; heteropoly acids and isopoly acids; You may mix and use.

Among them, boron trifluoride, or boron trifluoride diethyl etherate, boron trifluoride dibutyl etherate, boron trifluoride dioxanate, boron trifluoride acetic unhydrate, boron trifluoride Boron trifluoride coordination compounds such as triethylamine complex compounds are preferred. These (D) cationic polymerization catalysts may be used as they are, may be diluted in advance with an organic solvent or the like, or may be used by mixing with an inert gas such as nitrogen, and the preparation method is not particularly limited. The amount of the (D) cationic polymerization catalyst used is preferably 0.000 or more in total with respect to (A) trioxane.
1 to 0.02% by weight. (D) If the amount of the cationic polymerization catalyst exceeds 0.02% by weight, the thermal stability of the resin is reduced. If the amount is less than 0.0001% by weight, the polymerization activity is remarkably reduced, which is not preferable.

In the production of the polyacetal resin of the present invention, the above-mentioned (A) trioxane, (B) cyclic ether and / or cyclic formal, and (C) monoglycidyl ether compound are prepared by using (D) a cationic polymerization catalyst to form a bulk. In producing a polyacetal resin by polymerization, (B) a cyclic ether and / or cyclic formal, (C) a monoglycidyl ether compound, and (D) a cationic polymerization catalyst are once mixed, and this mixture is mixed with (A) trioxane. Is added and supplied for polymerization.

As a specific method, the following (A) to (A)
(D) and the like. (A) A method in which a mixture obtained by simultaneously mixing (B) a cyclic ether and / or cyclic formal, (C) a monoglycidyl ether compound, and (D) a cationic polymerization catalyst is added to (A) trioxane, and the mixture is polymerized. (B) After preliminarily mixing (B) a cyclic ether and / or cyclic formal and (C) a monoglycidyl ether compound, a mixture obtained by further mixing (D) a cationic polymerization catalyst is added to (A) trioxane and supplied. And polymerization. (C) After preliminarily mixing (B) the cyclic ether and / or cyclic formal and (D) the cationic polymerization catalyst, a mixture obtained by further mixing (C) a monoglycidyl ether compound is added to (A) trioxane. A method of feeding and polymerizing. (D) a monoglycidyl ether compound (C);
After pre-mixing the cationic polymerization catalyst,
(B) A method in which a mixture obtained by mixing a cyclic ether and / or cyclic formal is added to (A) trioxane and supplied to carry out polymerization.

Among them, in particular, the above (b) and (c)
Is preferred in terms of operability and effects. In the above operation method, the mixture of (B) and (C), and the mixture thereof and (D), or the mixture of (C) and (D), and the mixture of (B) and (B) Mixing or (B)
In the case of mixing (C) with (C) and (C), or the mixture of (B), (C) and (D) simultaneously, the mixing method of each component is a conventionally known method. And is not limited to these.

Such mixing methods include, for example, a method of continuously joining and mixing in a pipe, a method of continuously joining and then mixing with a static mixer, and a method of once mixing in a vessel equipped with a stirrer. A method of supplying a mixed component is exemplified. In the mixing of the above components, the mixing temperature and the mixing time are not particularly limited. If specified, the mixing temperature is -70 to 150 ° C, preferably-
50-75 ° C. The mixing time is 0.05 to 1,
It is 200 seconds, preferably 0.1 to 600 seconds. Also,
In the mixing of the above components, the monoglycidyl ether compound (C) may be used in its entirety, or a part of the used amount may be used and the remaining amount may be added to (A) trioxane. Good.

The mixture of (B) the cyclic ether and / or cyclic formal and (C) the monoglycidyl ether compound and (D) the cationic polymerization catalyst mixed by the above method is added to and supplied to the liquefied (A) trioxane. To carry out bulk polymerization to produce a solid powder bulk polymer.

As a method of adding and supplying the mixture to the trioxane, a method of supplying the mixture to the trioxane in the polymerization machine, a method of supplying the mixture to the polymerization machine while washing the mixture with trioxane, or a method of washing the mixture with tosoxane to wash the mixture A method of mixing with a mixer and supplying to a polymerization machine is exemplified. The polymerization machine has two drive shafts inside, and a screw, paddle,
Examples include a kneader / co-kneader type polymerization machine in which mixing means such as a disk, a pin, and a blade are directly connected. Further, the polymerization temperature is preferably maintained at 65 to 135 ° C., and the polymerization machine residence time is preferably 0.2 to 30 minutes.

The deactivation of the catalyst after the polymerization is performed by adding a basic compound or an aqueous solution thereof to the reaction product discharged from the polymerization machine after the polymerization reaction or the reaction product in the polymerization machine. Examples of the basic compound for neutralizing and deactivating the polymerization catalyst include ammonia; amines such as triethylamine, tributylamine, triethanolamine and tributanolamine; hydroxides of alkali metals or alkaline earth metals. , Carbonate; and other known catalyst deactivators. After the polymerization step and the deactivation treatment, if necessary, washing, separation and recovery of unreacted monomers, drying and the like are further performed by a conventionally known method.

The obtained crude polyacetal resin flakes are further subjected to a stabilizing treatment by a known method, if necessary, such as separation and removal of unstable terminals or sealing of unstable terminals with a stabilizing substance. And various necessary stabilizers. Examples of the stabilizer used here include a hindered phenol compound, a nitrogen-containing compound, an alkali or alkaline earth metal hydroxide, an inorganic salt, a carboxylate, and the like. Two or more can be used. Furthermore, as long as the present invention is not impaired, if necessary, a general additive to the thermoplastic resin, for example, a coloring agent such as a dye or a pigment, a lubricant, a nucleating agent,
One or more kinds of release agents, antistatic agents, surfactants, or organic polymer materials, inorganic or organic fibrous, powdery, or plate-like fillers can be added.

By producing the polyacetal resin pellets as described above, the molecular weight distribution between the pellets can be eliminated, and the molecular weight distribution can be made uniform.
Although the reason is unclear, the mixture is efficiently and uniformly dispersed in trioxane by mixing the cationic polymerization catalyst, the cyclic ether and / or the cyclic formal, and the monoglycidyl ether compound in advance, and the polymerization reaction is performed. Is presumed to be performed uniformly, so that the molecular weight distribution is made uniform. According to the method for producing a polyacetal resin of the present invention, a polyacetal resin having stable quality can be produced. Further, in the molded article using the polyacetal resin obtained in the present invention, minute foreign matter generated on the surface is reduced, and the surface appearance is improved. Furthermore, the polyacetal resin obtained in the present invention has excellent balance of mechanical properties, chemical resistance, slidability, etc., and also has excellent moldability, so that it can be used not only for injection molded products, but also for extruded products, blow molded products, It is useful in various fields such as molded articles.

[0026]

EXAMPLES Hereinafter, the present invention will be described specifically, but the present invention is not limited to these examples. In the present invention, when a weight% of the substance A is referred to as trioxane,
It means that the weight ratio of substance A / trioxane is a% by weight / 100% by weight. The melt index of the polyacetal resin was measured according to ASTM D1238.

Embodiment 1 A jacket (reactor body) having a cross section in which two circles partially overlap each other is provided with a jacket through which a heat (cooling) medium passes, and a rotation axis is provided at the center of each of the circles. Trioxane containing 0.04 parts by weight of methylal (vs. trioxane) was added to one end of the reactor while rotating two rotating shafts with paddles at 100 rpm in opposite directions using a continuous mixing reactor. Feeded continuously. Subsequently, at the same time, 3.5% by weight of 1,3-dioxolane and 0.1% by weight of phenylglycidyl ether (both with respect to trioxane) were continuously mixed and mixed in a pipe, and further mixed with this.
0.002% by weight of boron trifluoride (relative to trioxane) was combined and mixed, and the mixture was cooled to -5 ° C and bulk polymerization was carried out while continuously adding and supplying trioxane in the polymerization machine. The reaction product discharged from the polymerization machine outlet is:
While passing through a crusher immediately, triethylamine was added to 0.1 ml.
The catalyst was deactivated at the same time as pulverized into particles by adding to an aqueous solution at 60 ° C. containing 05% by weight. Further, after separation, washing and drying, a crude polyacetal resin was obtained. Then, pentaerythritol tetrakis [3- (3,5-) was used as a stabilizer with respect to 100 parts by weight of the crude polyacetal resin.
Di-tert-butyl-4-hydroxyphenyl) propionate] (Irganox 1010, manufactured by Ciba-Geigy)
3 parts by weight and 0.15 parts by weight of melamine were added, mixed using a Henschel mixer, and then melt-kneaded at 200 ° C. in a twin-screw extruder equipped with a vent to stabilize and simultaneously form a pelletized polyacetal resin. (Melt index: 2.2 g / 1Omin).

GPC measurement was performed on each of the 100 pellets arbitrarily selected to determine the weight average molecular weight / number average molecular weight, that is, the molecular weight distribution. The difference in molecular weight distribution between the pellets was standard deviation / average value, and And the maximum value / average value was used as an index. The smaller these values are, the smaller the difference in molecular weight distribution between the pellets is, indicating that polyacetal resin pellets with stable quality could be produced. GPC was measured using a hexafluoroisopropanol solution containing trifluoroacetic acid as a solvent and a carrier under the conditions of a sample solution concentration of 0.1 wt%, a column oven temperature of 40 ° C., and a carrier liquid flow rate of 0.2 ml / min. The weight-average molecular weight and the number-average molecular weight were calculated by a conventional method based on the PMMA standard sample. Table 1 shows the results.

Example 2 Using the same continuous mixing reactor as in Example 1, trioxane containing 0.04% by weight of methylal (based on trioxane) was continuously supplied. Subsequently, at the same time, 0.002% by weight of boron trifluoride was added to 3.5 parts of 1,3-dioxolane.
% By weight (all with respect to trioxane). Then, 0.1% by weight of phenylglycidyl ether (based on trioxane) was further mixed and mixed in the pipe, and the mixture was cooled to -5 ° C and continuously added and supplied to trioxane in the polymerization machine. Polymerization was performed. Subsequently, the same treatment as in Example 1 was performed to obtain a pelletized polyacetal resin (melt index 2.1 g).
/ 10 min), and the difference in molecular weight distribution between the pellets was evaluated in the same manner as in Example 1. Table 1 shows the results.

Example 3 In the same manner as in Example 1, trioxane containing 0.04% by weight of methylal (based on trioxane) was continuously supplied using a continuous mixing reactor. Subsequently, simultaneously, 3.5% by weight of 1,3-dioxolane, 0.1% by weight of phenylglycidyl ether, and 0.002% by weight of boron trifluoride
(All with trioxane) were continuously mixed and mixed in a pipe at the same time, and then the mixture was cooled to −5 ° C. to perform bulk polymerization while continuously adding and supplying trioxane in a polymerization machine. Was. Subsequently, the same treatment as in Example 1 was performed to produce a pellet-like polyacetal resin (melt index: 2.3 g / 10 min), and the difference in molecular weight distribution generated between the pellets was evaluated in the same manner as in Example 1. Table 1 shows the results.

Example 4 Bulk polymerization was carried out in the same manner as in Example 1 except that boron trifluoride diethyl etherate was used in place of boron trifluoride at 0.005% by weight (based on trioxane). Subsequently, the same treatment as in Example 1 was performed to obtain a pelletized polyacetal resin (melt index: 2.2 g / 10 mi).
n) was prepared, and the difference in molecular weight distribution generated between the pellets was evaluated in the same manner as in Example 1. Table 1 shows the results.

Example 5 Instead of 3.5% by weight of 1,3-dioxolane, 1,4
-Bulk polymerization was carried out in the same manner as in Example 1 except that 4.0% by weight of butanediol formal (based on trioxane) was used. Subsequently, the same treatment as in Example 1 was performed to obtain a pelletized polyacetal resin (melt index 2.3 g / 1).
0 min), and the difference in molecular weight distribution between the pellets was evaluated in the same manner as in Example 1. Table 1 shows the results.

Example 6 Instead of 0.1% by weight of phenylglycidyl ether,
Bulk polymerization was carried out in the same manner as in Example 1, except that 0.2% by weight of stearyl glycidyl ether (based on trioxane) was used. Subsequently, the same treatment as in Example 1 was performed to obtain a pelletized polyacetal resin (melt index: 2.4 g /
10 min), and the difference in molecular weight distribution between the pellets was evaluated in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 1 In the same manner as in Example 1, a continuous mixing reactor was used, and at one end, 3.5% by weight of 1,3-dioxolane and 0.1% of methylal were used.
Trioxane was added continuously with addition of 04% by weight and 0.1% by weight of phenylglycidyl ether (all relative to trioxane). Subsequently, at the same time, bulk polymerization was performed while continuously adding and supplying 0.002% by weight of boron trifluoride (relative to trioxane) to the polymerization machine. next,
By treating in the same manner as in Example 1, a pellet-like polyacetal resin (melt index: 2.3 g / 10 min) was produced, and the difference in molecular weight distribution generated between the pellets was evaluated in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 2 In the same manner as in Example 1, a continuous mixing reactor was used, and one end of which contained 0.04% by weight of methylal and 3.5% by weight of 1,3-dioxolane (all based on trioxane). Trioxane was fed continuously. Subsequently, at the same time, 0.1% by weight of phenylglycidyl ether and 0.002% by weight of boron trifluoride (both with respect to trioxane) were continuously mixed and mixed in a pipe, and then the mixture was cooled at -5 ° C.
And the bulk polymerization was carried out while continuously adding and supplying to the polymerization machine. After performing the continuous operation for 5 minutes, the supply flow rate of boron trifluoride was disturbed, and then the supply of boron trifluoride was stopped. When the inside of the pipe was examined, generation and adhesion of a polymer were found at the catalyst supply port.

[0036]

[Table 1]

Examples 7 to 8 and Comparative Example 3 The polyacetal resin pellets obtained in Examples 1 and 2 and Comparative Example 1 were rolled at an extrusion temperature of 200 ° C. by an extruder equipped with a coat hanger die having a width of 100 mm. A sheet having a thickness of 1.0 mm was formed at a temperature of 50 ° C. Molding was carried out at three levels of rotation of the extruder: low, medium, and high. Foreign substances generated on the sheet surface were visually observed, and good, somewhat good, and poor were evaluated according to the rate of occurrence. Table 2 shows the results.

[0038]

[Table 2]

[0039]

According to the method for producing a polyacetal resin of the present invention, it is possible to eliminate a difference in molecular weight distribution generated between pellets of the polyacetal resin and to produce a polyacetal resin having stable quality.

Claims (6)

[Claims] 1. A method for producing a polyacetal resin by subjecting (A) trioxane, (B) a cyclic ether and / or cyclic formal, and (C) a monoglycidyl ether compound to bulk polymerization using a (D) cationic polymerization catalyst. (B) a cyclic ether and / or cyclic formal,
A method for producing a polyacetal resin, wherein a mixture obtained by mixing (C) a monoglycidyl ether compound and (D) a cationic polymerization catalyst is added to (A) trioxane and supplied to carry out polymerization. 2. A mixture obtained by previously mixing (B) a cyclic ether and / or cyclic formal and (C) a monoglycidyl ether compound, and further adding (D) a cationic polymerization catalyst to (A) trioxane. The method for producing a polyacetal resin according to claim 1, wherein the polyacetal resin is supplied and polymerized. 3. A mixture obtained by mixing (B) a cyclic ether and / or cyclic formal and (D) a cationic polymerization catalyst in advance, and further adding (C) a monoglycidyl ether compound to (A) trioxane. The method for producing a polyacetal resin according to claim 1, wherein the polyacetal resin is supplied and polymerized. 4. The method according to claim 1, wherein (D) the cationic polymerization catalyst is at least one selected from the group consisting of boron trifluoride and a boron trifluoride coordination compound.
3. The method for producing a polyacetal resin according to any one of 3. 5. The method according to claim 1, wherein (B) the cyclic ether and / or cyclic formal is ethylene oxide, 1,3-dioxolan,
The method for producing a polyacetal resin according to any one of claims 1 to 4, wherein the method is at least one selected from the group consisting of diethylene glycol formal and 1,4-butanediol formal. 6. The method according to claim 1, wherein the monoglycidyl ether compound (C) is at least one selected from the group consisting of compounds represented by the following general formula (1). 3. The method for producing a polyacetal resin according to item 1. Embedded image