JPH0649155A - Production of oxymethylene copolymer - Google Patents

Abstract

PURPOSE:To obtain an oxymethylene copolymer excellent in moldability and hue and also in hydrolysis resistance by polymerizing a mixture of trioxane with a cyclic ether in the presence of a polymerization catalyst, deactivating the catalyst, adding water together with a specified stabilizer to the reaction mixture, and heating the resulting mixture. CONSTITUTION:A process for producing an oxymethylene copolymer comprising oxymethylene units and other oxyalkylene units by polymerizing a mixture of trioxane with a cyclic ether in the presence of at least one polymerization catalyst selected from the group consisting of boron trifluoride, boron trifluoride hydrate and a coordination compound of boron trifluoride with an organic compound containing an oxygen or sulfur atom. This process comprises deactivating the catalyst after the polymerization, adding 0.001-1.0 pt.wt., per 100 pts.wt. crude polymer, alkaline earth metal salt of a fatty acid, 0.001-1.0 pt.wt. fatty acid amide, 0.001-1.0 pt.wt. antioxidant and 0.1-10 pts.wt. water to the reaction mixture, and heating the resulting mixture to 100-260 deg.C.

Description

Detailed Description of the Invention

[0001]

The present invention relates to the production of an oxymethylene copolymer by polymerizing a mixture of trioxane and a cyclic ether in the presence of a catalyst, deactivating the polymerization catalyst after completion of the polymerization, and then adding an alkaline earth fatty acid. By adding water together with the metal salt, fatty acid amide, and antioxidant,
The present invention relates to a method for producing an oxymethylene copolymer having excellent moldability, color tone, and hydrolysis resistance.

[0002]

2. Description of the Related Art A method for obtaining an oxymethylene copolymer by polymerizing trioxane and a cyclic ether in the presence of a polymerization catalyst is known. However, the oxymethylene copolymer thus obtained cannot be used as it is as a molding material. For practical use, the polymerization catalyst must first be deactivated, the unstable moieties removed or protected, and then a stabilizer included to prevent further decomposition. Of these, if the catalyst is not deactivated, the polymer undergoes depolymerization to cause a remarkable decrease in the molecular weight, and formaldehyde gas having an irritating odor is generated. On the other hand, when the unstable portion is not sufficiently removed or protected, not only is itself emitted as a formaldehyde gas having an irritating odor,
Formaldehyde is oxidized to formic acid, which decomposes the main chain of the polymer and causes depolymerization, and formaldehyde gas is generated violently with a remarkable decrease in molecular weight. Also,
When the content of the stabilizer is insufficient, even if a part of the polymer is decomposed even once by oxidative decomposition, formic acid generated by the oxidation of formaldehyde generated thereby is decomposed in a chain to generate a large amount of formaldehyde gas. Therefore, in order to achieve the stability of the oxymethylene copolymer that is put to practical use, the catalyst is deactivated to completely remove the unstable portion, and at the same time, the stabilizer that traps the generated formaldehyde and the stabilizer that prevents the oxidation. Must be added (JP-A-1-153711).

[0003]

However, the oxymethylene copolymers which have been put into practical use so far are decomposed during melt-molding because any one of them is insufficient, and when oxymethylene copolymer is molded due to an irritating odor. The mold deposit is thought to have deteriorated the environment of the product, or that the generated formaldehyde gas has adhered to the mold to form an oligomer, which necessitates frequent mold cleaning, or the thermal stability of the molded product is low and it is excellent in actual use. Heat resistance could not be obtained. In particular, many methods have been proposed so far for removing or protecting the unstable portion and adding a stabilizer, but none of them have been proposed, and it is natural that an irritating odor is generated when the oxymethylene copolymer is molded. Further, it has become common knowledge that the mold is provided with a gas vent for releasing generated formaldehyde gas, and the mold is further cleaned at regular intervals. Attempts have been made to suppress these decompositions by adding a large amount of various stabilizers, but the deterioration of the color tone of oxymethylene copolymer cannot be avoided.

The object of the present invention is to provide an oxymethylene copolymer which is excellent in moldability and has excellent color tone, such that there is no formaldehyde gas and mold deposit at the time of molding by sufficiently stabilizing the oxymethylene copolymer. To provide a method of obtaining.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that after the catalyst is deactivated after the completion of polymerization, an alkaline earth metal salt of a fatty acid, a fatty acid amide,
It has been found that the addition of water together with an antioxidant makes it possible to obtain an oxymethylene copolymer having excellent moldability, color tone, and hydrolysis resistance, and has reached the present invention.

That is, the present invention provides a mixture of trioxane and a cyclic ether from boron trifluoride, boron trifluoride hydrate and a coordination compound of boron trifluoride and an organic compound containing an oxygen atom or a sulfur atom. When producing an oxymethylene copolymer containing an oxymethylene unit and another oxyalkylene unit by polymerizing in the presence of at least one polymerization catalyst selected from the group consisting of, after depolymerizing the polymerization catalyst, the crude polymer is Based on 100 parts by weight, (A) an alkaline earth metal salt of a fatty acid 0.001 to 1.0
Parts by weight (B) fatty acid amide 0.001 to 1.0 parts by weight (C) antioxidant 0.001 to 1.0 parts by weight (D) water 0.1 to 10 parts by weight, and 100 to 260 ° C. The method for producing an oxymethylene copolymer is characterized by heating in the temperature range of.

Among the cyclic ethers used in the present invention, preferred compounds include ethylene oxide, propylene oxide, 1,3-dioxolane, 1,3-dioxane,
1,3-dioxepane, 1,3,6-trioxocane,
Examples thereof include epichlorohydrin and phenylglycidyl ether, with ethylene oxide, 1,3-dioxolane and 1,3-dioxepane being particularly preferred. The copolymerization amount is preferably in the range of 0.1 to 10 mol% and particularly preferably in the range of 0.2 to 6 mol% with respect to the oxymethylene unit. If it is 0.1 mol% or less, the thermal stability of the obtained polymer is low, and if it is 10 mol% or more, the mechanical strength and moldability are deteriorated, which is not preferable.

The polymerization catalyst of the present invention is one or more selected from the group consisting of boron trifluoride, boron trifluoride hydrate and a coordination compound of boron trifluoride with an organic compound containing an oxygen atom or a sulfur atom. The compounds are used in the form of a gas, liquid or a suitable organic solvent.

Among these catalysts, a coordination compound of boron trifluoride is particularly preferable, and boron trifluoride.
Diethyl etherate and boron trifluoride / dibutyl etherate are preferably used.

The addition amount of the polymerization catalyst is preferably in the range of 0.001 to 0.1 part by weight, and particularly preferably in the range of 0.005 to 0.05 part by weight, relative to 100 parts by weight of trioxane.

There are various known devices for polymerizing trioxane and cyclic ethers.
The present invention is not particularly limited to the apparatus, and can be applied to bulk polymerization and polymerization reaction performed in the presence of an organic solvent such as cyclohexane.

In bulk polymerization, rapid solidification and heat generation occur during polymerization, so an apparatus having a strong stirring ability and capable of controlling the reaction temperature is preferably used.

As the bulk polymerization apparatus of the present invention having such performance, a kneader having a sigma type stirring blade, a cylindrical parel as a reaction zone, and a screw having a large number of interrupted ridges coaxially in the parel are used. A mixer that operates so that the interrupted portion and teeth protruding from the inner surface of the parell mesh with each other; a normal screw extruder having a pair of mutually parallel parallel screws in a long case having a jacket for heating or cooling; Self-cleaning mixer with multiple paddles on a horizontal stirring shaft of a book, and when the shafts are simultaneously rotated in the same direction, they rotate with a slight clearance between the paddle surface and the inner surface of the case. And so on.

In bulk polymerization, solidification rapidly occurs at the beginning of the polymerization reaction, so that strong stirring ability is required. However, once pulverized, large stirring ability is not required thereafter, so bulk polymerization is not necessary. The process may be divided into two steps.

The bulk polymerization reaction temperature is preferably in the range of 30 to 120 ° C, particularly preferably in the range of 60 to 90 ° C.

At the initial stage of the polymerization, the temperature in the polymerization reaction device tends to rise due to the reaction heat and the frictional heat caused by solidification. Therefore, the reaction temperature can be controlled by passing cooling water through the jacket. desirable.

In the present invention, it is important that the catalyst is deactivated, but the method may be any method. For example, a method of deactivating a catalyst by contacting a crude polymer after polymerization with a large amount of an aqueous solution of a basic compound such as triethylamine or sodium carbonate has been known for a long time. This method is not preferable because it colors the oxymethylene copolymer when a trace amount of the basic compound remains, but it is sufficient for the present invention by spending sufficient time and completely washing after deactivation. It is possible to obtain a crude polymer deactivated.

Examples of the method for deactivating the preferred catalyst of the present invention include a method of adding a hindered amine compound or a trivalent organic phosphorus compound after the completion of polymerization. Of these, the method of adding a hindered amine compound to deactivate the catalyst is particularly preferable.

Typical hindered amine compounds that deactivate the catalyst used in the present invention and terminate the polymerization reaction include:
Bis (2,2,6,6-tetramethyl-4-piperidinyl) sebacate, Bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, 1,2,3,4
-Butane tetracarboxylic acid tetrakis (2,2,6,6
-Tetramethyl-4-piperidinyl) ester, poly [[6- (1,1,3,3-tetramethylenebutyl) amino-1,3,5-triazine-2,4-diyl]
[(2,2,6,6-Tetramethyl-4-piperidinyl) imino] hexamethylene [(2,2,6,6-tetramethyl-4-piperidinyl) imino], 1,2,2
6,6, -Pentamethylpiperidine, dimethyl succinate. 1- (2-hydroxyethyl) -4-hydroxy-
2,2,6,6-Tetramethylpiperidine polycondensate, and N, N′-bis (3-aminopropyl) ethylenediamine.2,4-bis [N-butyl-N- (1,2,
2,6,6-Pentamethyl-4-piperidyl) amino]
-1,3,5-triazine condensate is mentioned, especially bis (2,2,6,6-tetramethyl-4-piperidinyl)
Sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, dimethyl succinate
1- (2-hydroxyethyl) -4-hydroxy-2,
2,6,6-tetramethylpiperidine polycondensate, N,
N'-bis (3-aminopropyl) ethylenediamine
2,4-bis [N-butyl-N- (1,2,2,6,6
-Pentamethyl-4-piperidyl) amino] -1,3,
The 5-triazine condensate is preferred. The addition amount is 0.001 to 5 parts by weight, preferably 0.01 to 3 parts by weight, based on 100 parts by weight of oxymethylene copolymer. 0.001
If the amount is less than 5 parts by weight, the effect of improving the moldability and hydrolysis resistance of the oxymethylene copolymer will not be obtained, and if it is more than 5 parts by weight, the bleeding phenomenon will be exhibited or the mechanical properties will be deteriorated. Further, the hindered amine compound may be added as it is, or may be added after being dissolved in an organic solvent such as benzene, toluene or cyclohexane.

Examples of the alkaline earth metal salt of fatty acid used in the present invention include acetic acid, propionic acid, lauric acid, myristic acid, palmitic acid, stearic acid, aragic acid,
Examples thereof include magnesium salts such as heptadecyl acid, behenic acid, oleic acid, linoleic acid, linoleic acid, ricinoleic acid, 12-hydroxystearic acid, montanic acid, and dimer acid, calcium salts, strontium salts, and barium salts. Magnesium acid, calcium laurate, magnesium stearate, magnesium behenate, calcium behenate, calcium 12-hydroxystearate and calcium 12-hydroxystearate can be preferably used.

The amount of the alkaline earth metal salt of fatty acid added is preferably 0.001 to 1.0 part by weight, particularly 0.01 to 0.5 part by weight, relative to 100 parts by weight of the crude polymer.
If the amount is less than 0.001 part by weight, the effect of improving the moldability and hydrolysis resistance of the oxymethylene copolymer is not observed, and
If it is more than 1.0 part by weight, bleed-out and deterioration of mechanical properties are observed, which is not preferable.

The fatty acid amide used in the present invention includes
Examples thereof include palmitic acid amide, stearic acid amide, oleic acid amide, ethylenebisstearic acid amide, ethylenebis-12-hydroxystearic acid amide, and methylenebisstearic acid amide. Among them, especially ethylene bis-stearic acid amide, ethylene bis-1
2-hydroxystearic acid amide is preferred.

The fatty acid amide is added in an amount of 0.001 to 1.0 part by weight, particularly 0.01 to 100 parts by weight of the crude polymer.
The range of 0.5 to 0.5 parts by weight is preferable, and if it is less than 0.001 parts by weight, the effect of improving the moldability of the oxymethylene copolymer is not seen, and if it is more than 1.0 parts by weight, bleed-out and coloring, It is not preferable because mechanical properties are deteriorated.

Examples of the antioxidant used in the present invention include phenol-based antioxidants and amine-based antioxidants. Among them, from the viewpoint of bleeding phenomenon and heat resistance, hindered compounds having a molecular weight of 400 or more are particularly preferable. Phenolic compounds are preferred. As a specific example, triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-)
Hydroxyphenyl) propionate], pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-
4-hydroxyphenyl) propionate], 1,6-
Hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,
2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate],
N, N'-hexamethylenebis [3- (3,5-di-t
-Butyl-4-hydroxyphenyl) propionamide], 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl)
Benzene, 2,4-bis (n-octylthio) -6-
(4-hydroxy-3,5-di-t-butylanilino)
-1,3,5-triazine, octadecyl-3- (3,3
5-di-t-butyl-4-hydroxyphenyl) propionate, 2,2-thiobis (4-methyl-6-t-butylphenol), 3,5-di-t-butyl-4-hydroxybenzylphosphonate- Diethyl ester,
1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, 1,
1,3-tris (2-methyl-4-hydroxy-5-t
-Butylphenyl) butane, N, N'-bis [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionyl] hydrazine, 2-t-butyl-6-
(3'-t-butyl-5'-methyl-2'-hydroxybenzyl) -4-methylphenyl-acrylate, 3,
9-bis [2- {3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,
1-Dimethylethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane and the like can be mentioned. Among them, triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], pentaerythrityl-tetrakis [3- (3,3
5-di-t-butyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionate], N, N′-hexamethylenebis [3
-(3,5-Di-t-butyl-4-hydroxyphenyl) propionamide] is preferred.

The amount of the antioxidant added is 0.001 to 1.0 part by weight, particularly 0.1 to 1.0 part by weight, based on the oxymethylene copolymer.
A range of 0.7 parts by weight is preferred. If the addition amount is less than 0.001 part by weight, the effect of improving the moldability and hydrolysis resistance of the oxymethylene copolymer is not sufficient, and if it is more than 1.0 part by weight, the bleeding phenomenon and the deterioration of mechanical properties are observed, which is preferable. Absent.

The amount of water used in the present invention is 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, more preferably 1.0 to 3 parts by weight, based on 100 parts by weight of oxymethylene copolymer. Parts by weight. If it is less than 0.1 part by weight, the improvement effect of the oxymethylene copolymer intended by the present invention is small, and if it is more than 10 parts by weight, further improvement effect cannot be expected, and conversely, the temperature rise in the next heating step. It will take some time to complete.

In addition, when the oxymethylene copolymer of the present invention is added and blended with other heat stabilizer, the heat stability may be further improved. Examples of such compounds include urethane compounds, pyridine derivatives, pyrrolidone derivatives, urea derivatives, triazine derivatives, hydrazine derivatives, amidine compounds, polyamides and polyamide copolymers, polyacrylamides and polyacrylamide copolymers, ethylene / vinyl alcohol copolymers. Examples thereof include coalescing, and specifically, melamine, benzoguanamine, acetoguanamine, N-methylolmelamine, N, N′-dimethylolmelamine, N, N ′, N ″ -trimethylolmelamine, dicyandiamide, nylon 6, Nylon 6/12
Copolymers, nylon 6/66/610 ternary copolymers, nylon 6/66/610/12 quaternary copolymers, polyacrylamide and the like are preferable. The amount of these heat stabilizers added is usually 100 parts by weight of oxymethylene copolymer.
0.001-1.0 parts by weight, preferably 0.01-0.
5 parts by weight. If it is less than 0.001 part by weight, the effect of addition does not appear, and if it is more than 1.0 part by weight, coloring or bleeding phenomenon is observed, which is not preferable.

Further, the composition of the present invention contains calcium carbonate, barium sulfate, clay, titanium oxide, silicon oxide, mica powder, fillers such as glass beads, carbon fiber, and glass as long as the effects of the present invention are not impaired. Reinforcing agents such as fibers, ceramic fibers, aramid fibers, potassium titanate fibers,
Colorants (pigments, dyes), nucleating agents, plasticizers, release agents such as polyethylene wax, conductive agents such as carbon black, light stabilizers such as benzophenone compounds and benzotriazole compounds, adhesives, lubricants An additive such as a hydrolysis resistance improver or an adhesion promoter can be optionally contained.

In the present invention, the temperature at the time of adding water together with the stabilizer and heating is preferably in the range of 100 ° C to 260 ° C, preferably 170 ° C to 260 ° C.

Examples will be described below, but the present invention is not limited thereto.

[0031]

The present invention will be described below with reference to examples. All percentages and parts in the examples are by weight.

MI shown in Examples and Comparative Examples
The value, heat decomposition rate Kx, molding, color tone, formaldehyde odor during molding, low mold deposit property, mechanical properties, and hydrolysis resistance were measured as follows.

MI value: Using pellets dried in a hot air oven at 80 ° C. for 3 hours, the temperature was measured at 190 ° C. at a load of 2160 grams according to the ASTM D-1238 method.

· Thermal decomposition rate K246: K246 is 24
It means the decomposition rate when left to stand at 6 ° C for a certain period of time.
It was allowed to stand at 246 ° C. for 40 minutes under an air flow of ml / minute, and calculated by the following formula.

Kx = (W0-W1) * 100 / W0 Here, W0 means the sample weight before heating, and W1 means the sample weight after heating. As the thermobalance device, TG / DTA200 manufactured by Seiko Instruments Inc. was used.

Molding: using an injection molding machine having a mold clamping pressure of 40 tons, cylinder temperature 240 ° C., mold temperature 30
The No. 1 dumbbell test piece of ASTM No. 1 was injection-molded at 0 ° C. and the molding cycle was set to 10 seconds.

Color tone: Using the Suga Test Instruments SM color computer SM-3, set the above ASTM No. 1 dumbbell to 3
The sheets were piled up and the YI value was measured.

Formaldehyde odor during molding: In the above molding, the formaldehyde concentration in the molding machine hopper was measured during 300 shots molding (ppm).

Low mold deposit property: In the above molding, the generation of deposits on the cavity surface of the mold was observed during 5000 shots molding. ○: No occurrence Δ: Slight occurrence ×: Clear It has occurred

Mechanical properties: AS obtained by the above injection molding
Using the TM1 dumbbell test piece, ASTM D-638
The tensile strength was measured according to the method.

Hydrolysis resistance: No. 1 dumbbell specified in ASTM D638 is put in a pressure vessel filled with pure water and heated in a hot air oven at 120 ° C. for 20 minutes.
After a day, the dumbbell was taken out and a tensile test was conducted by the same method as above. The strength retention was determined by comparison with the initial value (%).

In Examples 1 to 10 and Comparative Examples 1 to 7,
Oxymethylene crude polymer (POM manufactured by the following method
-1) was used.

Production of Oxymethylene Crude Polymer (POM-1) A twin-screw extruder type polymerization machine (100 mmφ, cylinder length (L) / cylinder diameter (D) = 10) was charged with trioxane (30 kg / h), 1, 3-dioxolane (1200g
/ H), and 130 ppm of boron trifluoride diethyl etherate (2.25% benzene solution) and 750 ppm of methylal to trioxane, respectively.
Continuous polymerization was carried out. Polymerization is performed with an outer jacket temperature of 45
The temperature was controlled at 0 ° C, and the rotation speed was 60 rpm. Methylal as a molecular weight regulator was dissolved in trioxane. Further, a premixing zone was provided so that the 1,3-dioxolane and the catalyst solution were premixed immediately before being supplied to the kneader. 27.3 kg of polymer as white fine powder
/ H.

Examples 1-10, Comparative Examples 1-7 A hindered amine compound was added as a 15-20% benzene solution to 1 kg of oxymethylene crude polymer (POM-1) at a ratio shown in Tables 1 and 2. The catalyst was deactivated by stirring in a Henschel mixer for 3 minutes. Water was added to the alkaline earth metal salts of fatty acids, fatty acid amides, and antioxidants shown in Tables 1 and 2, and further mixed in a Henschel mixer for 1 minute. This mixture was heated at a temperature of 240 using a biaxial 45 mmφ extruder with a vent manufactured by Ikegai Iron Works.
The mixture was melt-extruded and kneaded at a temperature of 10 ° C and a vacuum of 10 mmHg at the vent. The resulting polymer was extruded as strands and pelletized by a cutter. After drying these pellets in a hot air circulation oven at 80 ° C. for 3 hours, MI value and thermal decomposition rate Kx were measured and molded, and mechanical properties were measured. At the time of this molding, formaldehyde odor was measured and low mold deposit property was evaluated. Further, a hydrolysis resistance test was conducted using this molded product. The results are summarized in Tables 3 and 4.

[0045]

[Table 1]

[0046]

[Table 2]

HA-1: "Sanol" LS765 [manufactured by Sankyo Co., Ltd., bis (1,2,2,6,6-pentamethyl-
4-piperidinyl) sebacate] HA-2: "Tinuvin" 622LD [manufactured by Ciba Geigy, dimethyl succinate 1- (2-hydroxyethyl)]
-4-Hydroxy-2,2,6,6-tetramethylpiperidine polycondensate] HA-3: "Chimasorb" 119FL [Ciba Geigy, N, N'-bis (3-aminopropyl) ethylenediamine.2,4] -Bis [N-butyl-N- (1,2,
2,6,6-Pentamethyl-4-piperidyl) amino]
-6-Chloro-1,3,5-triazine condensate] HA-4: "SANOL" LS770 [manufactured by Sankyo Co., Ltd., bis (2,2,6,6-tetramethyl-4-piperidinyl) sebacate]

MS-1: 12-calcium hydroxystearate MS-2: calcium stearate MS-3: magnesium stearate MS-4: 12-hydroxy magnesium stearate MS-5: sodium carbonate MS-6: calcium hydroxide

AM-1: Ethylenebisstearic acid amide AM-2: Methylenebisstearic acid amide AM-3: Ethylenebis-12-hydroxystearic acid amide

AO-1: "Irganox" 245 [manufactured by Ciba Geigy, (triethylene glycol-bis [3
-(3-t-Butyl-5-methyl-4-hydroxyphenyl) propionate]] AO-2: "Irganox" 1010 [manufactured by Ciba-Geigy, pentaerythrityl-tetrakis [3- (3,5
-Di-t-butyl-4-hydroxyphenyl) propionate]] AO-3: "Irganox" 259 [manufactured by Ciba-Geigy, 1,6-hexanediol-bis [3-3,5-di-t-butyl-] 4-Hydroxyphenyl) propionate]]

HS-1: Polyamide 6/66/610 /
12 quaternary copolymer HS-2: melamine HS-3: polyacrylamide

[0052]

[Table 3]

[0053]

[Table 4]

As is clear from Tables 3 and 4, the oxymethylene copolymer obtained by the production method of the present invention is excellent in thermal stability and therefore excellent in moldability, color tone and hydrolysis resistance. I understand.

[0055]

EFFECTS OF THE INVENTION By using the method of the present invention, it is possible to produce oxymethylene copolymers which are used in a wide range of applications such as mechanical and mechanical parts and electric / electronic parts, with high quality and high productivity. .

Claims (10)

[Claims] 1. A mixture of trioxane and a cyclic ether is selected from the group consisting of boron trifluoride, boron trifluoride hydrate and a coordination compound of boron trifluoride and an organic compound containing an oxygen atom or a sulfur atom. When producing an oxymethylene copolymer containing an oxymethylene unit and another oxyalkylene unit by polymerizing in the presence of at least one polymerization catalyst, the polymerization catalyst is deactivated after completion of the polymerization, and then 100 parts by weight of the crude polymer is added. On the other hand, (A) fatty acid alkaline earth metal salt 0.001 to 1.0
Parts by weight (B) fatty acid amide 0.001 to 1.0 parts by weight (C) antioxidant 0.001 to 1.0 parts by weight (D) water 0.1 to 10 parts by weight, and 100 to 260 ° C. A method for producing an oxymethylene copolymer, which comprises heating in the temperature range of 1. 2. The method for producing an oxymethylene copolymer according to claim 1, wherein a hindered amine compound is added after the completion of the polymerization to deactivate the polymerization catalyst. 3. The polymerization catalyst is deactivated by adding a trivalent organic phosphorus compound after the completion of the polymerization.
A method for producing the oxymethylene copolymer described. 4. The alkaline earth metal salt of a fatty acid is at least one compound selected from calcium stearate, magnesium stearate, 12-hydroxy calcium stearate, and 12-hydroxy magnesium stearate. A method for producing an oxymethylene copolymer according to claim 1. 5. The method for producing an oxymethylene copolymer according to claim 1, wherein the fatty acid amide is at least one compound selected from ethylenebisstearic acid amide and 12-hydroxystearic acid amide. 6. The method for producing an oxymethylene copolymer according to claim 1, wherein the antioxidant is a hindered phenol compound having a molecular weight of 400 or more. 7. In addition to the compounds (A) to (D), (E)
The method for producing an oxymethylene copolymer according to claim 1, wherein 0.001 to 1.0 part by weight of a heat stabilizer is added. 8. The heat stabilizer is melamine or nylon 6 /
The method for producing an oxymethylene copolymer according to claim 6, which is a 66/610/612 quaternary copolymer. 9. An alkaline earth metal salt of fatty acid (A) 0.001 to 1.0 relative to 100 parts by weight of the crude polymer.
Parts by weight (B) 0.001 to 1.0 parts by weight of fatty acid amide (C) 0.001 to 1.0 parts by weight of antioxidant (D) 0.1 to 10 parts by weight of water, and using a mixer 2. The method for producing an oxymethylene copolymer according to claim 1, wherein the polymer is mixed at a temperature not higher than the melting point of the polymer and then heated in a temperature range of 100 to 260.degree. 10. An alkaline earth metal salt of fatty acid (A) 0.001 to 1.0 relative to 100 parts by weight of the crude polymer.
Parts by weight (B) 0.001 to 1.0 parts by weight of fatty acid amide (C) 0.001 to 1.0 parts by weight of antioxidant (D) 0.1 to 10 parts by weight of water, and using a mixer 2. The method for producing an oxymethylene copolymer according to claim 1, wherein the mixture is heated and kneaded in a temperature range of 170 to 260 [deg.] C. using a vented twin-screw extruder.