JPH0643544B2 - Oxymethylene copolymer composition - Google Patents

Description

The present invention relates to an oxymethylene copolymer composition having excellent heat resistance stability.

<Prior Art> It is known, for example, from JP-B-44-5234 to obtain oxymethylene homopolymer or copolymer by bulk polymerization of trioxane alone or trioxane and cyclic ether in the presence of a catalyst. The obtained polymer is thermally unstable as it is, so in the case of a homopolymer it is end-capped by esterification or the like, and in the case of a copolymer it is stabilized by decomposing and removing the unstable end. Prior to that, it is necessary to stop the reaction by deactivating the catalyst. That is, the oxymethylene homopolymer or copolymer obtained by cationically polymerizing trioxane, etc., gradually depolymerizes unless a catalyst remaining in the catalyst is deactivated, causing a remarkable decrease in molecular weight, or thermally It becomes extremely unstable.

Regarding the deactivation of the boron trifluoride-based polymerization catalyst, US Pat. No. 2,989,509 proposes to use an aliphatic amine or a heterocyclic amine, and these amines are used for the catalyst deactivation and washing. Therefore, if these are removed, the polymer is stabilized, and the molecular weight does not decrease even if it is stored as it is for a long time.

However, even if it is deactivated with a normal amine compound, unless the catalyst is removed from the polymer by washing, depolymerization also occurs when the polymer is melted or dissolved, and a decrease in molecular weight is observed. Therefore, after deactivating the catalyst with an amine, it was essential to remove the catalyst from the polymer by a thorough washing operation. For example, Japanese Patent Publication Sho-39-807
No. 1 and Japanese Examined Patent Publication No. 43-1875 describe methods for stabilizing the end of an oxymethylene copolymer. In these methods, the polymerization catalyst is deactivated with an amine prior to the end stabilization. It is removed by washing. Recently, a trivalent phosphorus compound has been found as a catalyst deactivator that does not need to be washed and removed, and is described in JP-B-55-42085. However, in order to produce an oxymethylene copolymer having higher thermal stability, it is indispensable to incorporate a stabilizer together with decomposition of unstable terminals after deactivation of the catalyst. Conventionally, various stabilizers have been known to be blended, and for example, JP-B-34-5440 describes stabilization by kneading a polyamide and a hindered phenol.

<Problems to be Solved by the Invention> Although the thermal stability is certainly increased by the kneading of the stabilizer as described above, if the mixture is left in a molten state for a long time in molding or the like, decomposed rice foams to form a mold deposit. I was not satisfied with the result. Furthermore, when washing and removal of the catalyst by the amine in the deactivation step is omitted, the thermal stability of the polymer is extremely low no matter what kind of stabilizer is kneaded, the polymer cannot withstand melt molding, etc. The thermal stability is insufficient even when a valent phosphorus compound is used.

The present inventors have conducted intensive studies to obtain an oxymethylene copolymer composition having excellent thermal stability, and as a result, have found the present invention.

<Means for Solving Problems> That is, the present invention provides a mixture of trioxane and a cyclic ether with boron trifluoride, boron trifluoride hydrate, and an organic compound containing boron trifluoride and an oxygen atom or a sulfur atom. In the presence of at least one polymerization catalyst selected from the group consisting of coordination compounds with and after bulk polymerization, the catalyst is deactivated by adding a hindered amine to the polymer, and an alkali metal hydroxide or alkaline earth metal is added to the polymer. One or more selected from hydroxides, alkali metal inorganic acid salts, alkaline earth metal inorganic acid salts, alkali metal organic acid salts, alkaline earth metal organic acid salts and alkali metal alkoxides, hindered phenolic antioxidants and formaldehyde Oxymethylene copolymer prepared by adding and mixing a reagent capable of reacting with and absorbing formaldehyde It is a composition.

The cyclic ether used in the present invention, the following general formula (A)
Means a compound represented by.

(However, Y _{1 to} Y _{4 in the} formula represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a halogen-substituted alkyl group having 1 to 6 carbon atoms, and they may be the same or different. or,
X represents a methylene or oxymethylene group, which may be substituted with an alkyl group or a halogen-substituted alkyl group,
m represents an integer of 0 to 3. Alternatively, X is - (CH ₂₎ p
-O-CH ₂ - or _{-O-CH 2 - (CH 2} ) p-O-CH 2 -
, Where m = 1 and p is 1
Is an integer of 3) Among the cyclic ethers or cyclic acetals represented by the general formula (A), ethylene oxide, propylene oxide, 1,3-dioxolane,
1,3-dioxane, 1,3-dioxepane, 1,3
5-trioxepane, 1,3,6-trioxocane, epichlorohydrin and the like can be mentioned.

The copolymerization amount of the cyclic ether of the present invention is required to be in the range of 0.1 to 10 mol%, particularly preferably 0.2 to 6 mol%, based on trioxane, and the copolymerization amount of 0.1 mol% or less is obtained. It is not preferable that the composition has low thermal stability, and if it is 10 mol% or more, the melting point and crystallinity of the composition obtained are lowered, resulting in poor mechanical strength and moldability.

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

Examples of the organic compound having an oxygen or sulfur atom which forms a coordination compound with boron trifluoride include alcohol, ether, phenol and sulfide.

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

As the solvent for the polymerization catalyst in the present invention, benzene, toluene, aromatic hydrocarbons such as xylene, n-hexane, n-heptane, aliphatic hydrocarbons such as cyclohexane, alcohols such as methanol and ethanol, chloroform, Halogenated hydrocarbons such as dichloromethane, 1,2-dichloroethane, ketones such as acetone and methyl ethyl ketone are used.

The amount of the polymerization catalyst added is 5 with respect to 1 mol of trioxane.
It is in the range of x10 ^-6 to 1 x 10 ^-1 mol, particularly preferably in the range of 1 x 10 ^-5 to 1 x 10 ^-2 mol.

Various apparatuses for bulk polymerization of trioxane alone or trioxane and cyclic ether are known, but the bulk polymerization used in the present invention is not particularly limited by the apparatus, and 10% by weight or less based on trioxane. Then, it can be applied to a polymerization reaction carried out in the presence of an organic solvent such as cyclohexane.

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

As the bulk polymerization apparatus of the present invention having such performance, a kneader having a sigma type stirring blade, a cylindrical barrel as a reaction zone, and a screw having coaxial and many interrupted peaks in the barrel, A mixer that operates so that the interruption portion and the teeth protruding on the inner surface of the barrel mesh with each other,
In a long case having a jacket for heating or cooling, a normal screw extruder having a pair of mutually parallel parallel screw screws, two horizontal stirring shafts having multiple paddles,
A self-cleaning mixer or the like that rotates when the shaft is simultaneously rotated in the same direction while maintaining a slight clearance between the mating paddle surface and the inner surface of the case can be used.

Also, in bulk polymerization, a strong stirring ability is required because it solidifies rapidly in the initial stage of the polymerization reaction, but once it is pulverized, a large stirring ability is not required thereafter, so the bulk polymerization step is performed twice. It may be divided into stages.

The bulk polymerization reaction temperature is preferably in the temperature range from near the melting point to near the boiling point of trioxane, that is, in the range of 60 to 115 ° C, particularly preferably in the range of 60 to 90 ° C.

At the initial stage of the polymerization, the temperature in the polymerization reaction apparatus tends to rise particularly due to the reaction heat or the frictional heat caused by solidification, so it is desirable to control the reaction temperature by passing cooling water through the jacket. .

The following compounds are mentioned as typical hindered amine compounds that deactivate the boron trifluoride-based catalyst used in the present invention to terminate the polymerization reaction.

Among these hindered amine compounds, a tertiary amine type hindered amine compound is particularly preferably used because the obtained polymer has an excellent color tone.

The addition amount of the hindered amine compound is preferably such that the number of nitrogen atoms having a hindered amine structure is equal to or more than the number of boron atoms of the boron trifluoride-based catalyst of the polymerization catalyst used. Even if the number of nitrogen atoms is less than the number of boron atoms, the catalyst deactivating effect can be seen, but the heat resistance stability of the obtained polymer is slightly lowered. Therefore, the addition amount is adjusted according to the desired degree of heat stability. There is a need.

Alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal inorganic acid salts, alkaline earth metal inorganic acid salts, alkali metal organic acid salts, alkaline earth metal organic acid salts and alkali metal alkoxides used in the present invention Specific examples of lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, sodium phosphate, sodium borate, sodium acetate , Magnesium acetate, sodium benzoate, sodium terephthalate, sodium methoxide, potassium methoxide, sodium ethoxide, potassium ethoxide, sodium isopropoxide and the like.

Alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal inorganic acid salts, alkaline earth metal inorganic acid salts, alkali metal organic acid salts, alkaline earth metal organic acid salts and alkali metal alkoxides used in the present invention Is added in an amount of 0.001 to 5% by weight based on the oxymethylene copolymer,
It is preferably 0.05 to 3% by weight. When it is less than 0.001% by weight, the thermal stability of the obtained composition is low, and 5
If it exceeds 5% by weight, mechanical properties and hydrolysis resistance are deteriorated, which is not preferable.

Examples of the hindered phenol type antioxidant used in the present invention include compounds represented by the following general formula (B).

(In the formula, X ¹ , X ² , and X ³ are an alkyl group, a halogenated alkyl group, an alkoxy group, a thioalkyl group, a halogenated alkoxy group, an aryl group, an aryloxy group, a substituted aryl group, a substituted aryloxy group, and amino. Group or a substituted amino group), specific compounds include 2,2-methylene-bis (4
-Methyl-6-tert-butylphenol), triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate],
2,2-thio-diethylenebis [3- (3,5-di-te
rt-Butyl-4-hydroxyphenyl) propionate], pentaerythrityl-tetrakis [3- (3,5
-Di-tert-butyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3-
(3,5-Di-tert-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino)- 1,3,5-triazine, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-trimethyl-
2,4,6-Tris (3,5-di-tert-butyl-4-
Hydroxybenzyl) benzene, 2,2-thiobis (4
-Methyl-6-tert-butylphenol), 1,3,5
-Tris (4-tert-butyl-3-hydroxy-2,6
-Dimethylbenzyl) isocyanuric acid, 3,5-di-te
rt-Butyl-4-hydroxybenzylphosphonate-diethyl ester, N, N′-hexamethylenebis (3,3
5-di-tert-butyl-4-hydroxy-hydrocinnamamide), bis (3,5-di-tert-butyl-4-hydroxybenzylphosphonate ethyl) calcium, N,
N'-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine, 2-
[2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2-
(3,5-di-tert-amyl-2-hydroxyphenyl) benzotriazole, 2- (3-tert-butyl-5
-Methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-tert-butyl-2)
-Hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-tert-butyl-2-hydroxyphenyl) benzotriazole, stearyl-3-
(3,5-di-tert-butyl-4-hydroxyphenyl) propionate or 2,2-bis [3- (3,3
5-di-tert-butyl-4-hydroxyphenylpropanoyloxy) methyl] -1,3-propanediol bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] Can be mentioned.

The amount of the hindered phenol antioxidant used in the present invention is 0.001 to the oxymethylene copolymer.
It is 5% by weight, preferably 0.05 to 3% by weight. 0.
If it is less than 001% by weight, the thermal stability of the obtained composition is low, and if it is more than 5% by weight, white powder is deposited on the surface of the oxymethylene copolymer, which is not preferable.

Examples of the agent capable of absorbing formaldehyde used in the present invention include amide compounds, urethane compounds, pyridine derivatives, pyrrolidone derivatives, urea derivatives, triazine derivatives, hydrazine derivatives, and amidine compounds. N-dimethylformamide,
N, N-dimethylacetamide, N, N-diphenylformamide, N, N-diphenylacetamide, N, N
-A single lactam such as diphenylbenzamide, N, N, N, N-tetramethyladipamide, oxalic acid dialinide, adipic acid dianilide, α- (N-phenyl) acetanilide, nylon 6, nylon 11 or nylon 12 Polyamides derived from polymers or copolymers, divalent carboxylic acids such as adipic acid, sebacic acid, decanedicarboxylic acid, dimer acid and diamines such as ethylenediamine, tetramethylenediamine, hexamethylenediamine, metaxylylenediamine Homopolymers or copolymers, polyamide copolymers derived from lactams and dicarboxylic acids and diamines, polyacrylamides, polymethacrylamides, N, N-bis (hydroxymethyl) sveramides, poly (γ-methylglutamates) ), Poly (γ-ethyl) Glutamate), poly (N- vinyl lactams), poly (N- vinylpyrrolidone) amide compounds such as, toluene diisocyanate, and diisocyanates such as diphenylmethane diisocyanate 1,
Polyurethanes derived from glycols such as 4-butanediol and polymeric glycols such as poly (tetramethylene oxide) glycol, polybutylene adipate, polycaprolactone, melamine, benzoguanamine, acetoguanamine, N-butylmelamine, N-phenylmelamine. , N, N-diphenylmelamine, N, N,
N-triphenylmelamine, N-methylolmelamine,
N, N-dimethylolmelanin, N, N, N-trimethylolmelamine, 2,4-diamino-6-benzyloxytriazine, 2,4-diamino-6-butoxytriazine, 2,4-diamino-6-cyclohexyl Triazine derivatives such as triazine, melem and melam, urea derivatives such as N-phenylurea, N, N-diphenylurea, thiourea, N-phenylthiourea, N, N-diphenylthiourea and nonamethylene polyurea, phenylhydrazine, Diphenyl hydrazine, benzaldehyde hydrazone, semicarbazone, 1-methyl-1-phenylhydrazone, thiosemicarbazone, 4- (dialkylamino) benzaldehyde hydrazone, 1-methyl-1-
Phenylhydrazone, hydrazine derivatives such as thiosemicarbazone, dicyandiamide, guanzidine, guanidine, aminoguanidine, guaninganacrine, guanoclor, guanoxane, guanosine, amiloride,
Amidine compounds such as N-amidino-3-amino-6-chloropyrazinecarboxamide, poly (2-vinylpyridine), poly (2-methyl-5-vinylpyridine),
Poly (2-ethyl-5-vinylpyridine), 2-vinylpyridine-2-methyl-5-vinylpyridine copolymer,
Examples thereof include pyridine derivatives such as 2-vinylpyridine-styrene copolymer.

Among them, diamic acid-based polyamide, melamine, guanamine, benzoguanamine, N-methylolated melamine, N
-Methylolated benzoguanamine, thermoplastic polyurethane resin, dicyandiamide, guanidine, poly (vinylpyrrolidone), poly (2-vinylpyridine), polyurea, melem, and melam have thermal stability of oxymethylene copolymers containing them. It is particularly preferable because it is excellent.

The amount of the reagent capable of absorbing formaldehyde is 0.001 to 5% by weight, preferably 0.05 to 3% by weight, based on the oxymethylene copolymer. 0.00
If it is less than 1% by weight, the thermal stability of the obtained composition is insufficient, and if it is more than 5% by weight, it may be deposited on the surface of the composition or the composition may be colored, which is not preferable.

The composition of the present invention is obtained by polymerizing trioxane and a cyclic ether with a boron trifluoride-based catalyst, adding a hindered amine compound as a catalyst activator to stop the polymerization reaction, and further adding an alkali metal or an alkaline earth metal. It is manufactured by adding and kneading salts, a hindered phenol-based antioxidant, and a formaldehyde absorbent. The additives may be added one by one, or may be added all at once. Further, the additive may be added as it is or may be added as a solution of an organic solvent.

Examples of the organic solvent at that time include aromatic hydrocarbons such as benzene, toluene and xylene, aliphatic hydrocarbons such as n-hexane, n-heptane and cyclohexane, alcohols such as methanol and ethanol, chloroform,
Examples thereof include halogenated hydrocarbons such as dichloromethane and 1,2-dichloroethane, and ketones such as acetone and methyl ethyl ketone.

Further, the composition of the present invention, calcium carbonate, barium sulfate, clay, titanium oxide, silicon oxide, filler such as mica powder, carbon fiber, glass fiber, ceramic fiber, aramid within the range that does not impair the effects of the present invention. Reinforcing agents such as fibers, colorants (pigments, dyes), nucleating agents, plasticizers, release agents, flame retardants, antistatic agents, conductive agents, adhesives, lubricants, hydrolysis resistance improvers, adhesion aids, etc. Can be optionally contained.

The oxymethylene copolymer composition produced by the present invention is excellent in moldability, mechanical properties, melt stability and heat aging resistance, and therefore has a wide range of applications such as mechanical mechanism parts, automobile parts, and electric / electronic parts. Can be used in.

<Example> Next, the present invention will be described with reference to Examples and Comparative Examples. In addition,
The surface condition, mechanical properties, relative viscosity ηr, thermal decomposition rate K, polymer melting point (T) of the molded products shown in Examples and Comparative Examples
m) and crystallization temperature (Tc) were measured as follows.

Surface condition of molded product: Cylinder temperature 230 ° C, mold temperature 60 ° C and molding cycle 5 using an injection molding machine having an injection capacity of 5 ounces.
The ASTM No. 1 dumbbell test piece and the Izod impact test piece were injection-molded at 0 second. The surface state of the obtained ASTM No. 1 dumbbell test piece was visually observed.

Mechanical Properties: Using the ASTM No. 1 dumbbell test piece obtained by the above injection molding, the tensile properties were measured according to the ASTM D-638 method. Also, using an Izod impact test piece, ASTM D
The impact strength was measured according to the -256 method.

Relative viscosity ηr: p-chlorophenol 10 containing 2% of α-pinene
0.5 g of polymer was dissolved in 0 ml and measured at a temperature of 60 ° C.

Thermal decomposition rate Kx: Kx means a decomposition rate when left standing at x ° C. for a certain time,
Using a thermobalance device, about 10 mg of sample was allowed to stand at x ° C. in an air atmosphere and determined by the following formula.

Kx = (W ₀ −W ₁ ) × 100 / W ₀ % where W ₀ means the sample weight before heating and W ₁ means the sample weight after heating.

The thermobalance device is a thermal analyzer 109 manufactured by DuPont.
0/1091 was used.

Polymer melting point (Tm), crystallization temperature (Tc): Using a differential scanning calorimeter, the temperature was raised at a temperature rising rate of 10 ° C./min in a nitrogen atmosphere, and after measuring the polymer melting point (Tm), 1
The temperature was lowered at 0 ° C./min, and the crystallization temperature (Tc) was measured.

Reference Example 1 A 3-liter kneader having two Σ-type stirring blades was placed at 60 ° C.
Then, 3.0 kg of trioxane, 112 g of 1,3-dioxolane, and boron trifluoride / diethyl etherate as a catalyst were added as 200% of a 10% benzene solution based on the weight of trioxane, and stirred at 30 ppm.

Within a few minutes, the internal temperature of the system rose due to the solidified reaction heat and frictional heat. Therefore, cool air was passed through the Σ-type stirring blade, and the rotation speed was reduced to 10 rpm to reach a maximum temperature of 80 rpm. The temperature was controlled up to ° C.

The stirring was continued and the polymer was taken out after 60 minutes.
The obtained polymer was a white powder with ηr = 2.37.

This polymer is referred to as oxymethylene copolymer A.

Reference Example 2 In Reference Example 1, instead of 1,3-dioxolane,
The polymer was bulk polymerized in the same manner as in Example 1 except that 66 g of ethylene oxide was used.

The obtained polymer was a white powder with ηr = 2.40.

This polymer is referred to as oxymethylene copolymer B.

Examples 1-5, Comparative Examples 1-2 As the oxymethylene copolymer A obtained in Example 1, various hindered amine compounds represented by the above structural formulas at a ratio shown in Table 1 were prepared as about 20% benzene solutions. Add 35
The mixture was kneaded at 15 ° C for 15 minutes. Then 0.1% by weight calcium hydroxide and 0.5% by weight pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (Ciba-Geigy). "Irganox" 1010) was added and 210 ° C for 10 minutes.
After the temperature was raised to, the mixture was kneaded at the same temperature for 20 minutes. Furthermore, 0.
Add 1 wt% dicyandiamide and add 10% at 210 ° C.
Kneaded for minutes.

For comparison, a composition was prepared using triphenylphosphine instead of the hindered amine compound.

Table 1 shows the results of measuring various physical properties of the obtained composition. Table 1
From the above, it is clear that the composition according to the present invention has excellent physical properties regardless of the kind of hindered amine compound.

Example 6 To the oxymethylene copolymer A obtained in Reference Example 1, the hindered amine compound, calcium hydroxide, “Irganox” 1010 and dicyandiamide were added all at once in the same proportions as in Example 2 and kneaded at 35 ° C. for 15 minutes. did. After that, the temperature was raised to 210 ° C. in 10 minutes and kneading was performed at the same temperature for 30 minutes. Table 1 shows the results of measuring various physical properties of the obtained composition.

Example 7 A hindered amine compound, calcium hydroxide and “Irganox” 1010 were simultaneously added to the oxymethylene copolymer A obtained in Reference Example 1 in the same proportions as in Example 2, and 3
The mixture was kneaded at 5 ° C for 15 minutes. Then 210 ° C for 10 minutes
After the temperature was raised to kneading and the mixture was kneaded at the same temperature for 20 minutes, 0.1 wt% of dicyandiamide was added and kneaded at the same temperature for 10 minutes.
Table 1 shows the results of measuring various physical properties of the obtained composition.

From Example 2 (sequential addition method), Example 6 (collective addition method), and Example 7 (collective addition of formaldehyde absorbent), the composition of the present invention has excellent physical properties regardless of the kneading method. it is obvious.

Examples 8 to 13 Compositions were produced in the same manner as in Examples 2, 6 and 7, except that magnesium hydroxide and potassium carbonate were used instead of calcium hydroxide.

Table 2 shows the results of measuring various physical properties of the obtained composition. Table 2
It is clear that the composition of the present invention has excellent physical properties regardless of the type of alkali or alkaline earth metal salt and the kneading method.

Examples 14-19 Instead of pentaerythrityl-tetrakis [3- (3-, 5-di-tert-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3
-(3-tert-butyl-5-methyl-4-hydroxyphenylpropionate] (Ciba-Geigy "Irgano
x ″ 245), N, N′-hexamethylenebis (3,5
-Di-tert-butyl-4-hydroxy-hydrocinnamamide) ("Irganox" 1098 from Ciba-Geigy) was used to prepare a composition in the same manner as in Examples 2, 6 and 7.

Table 3 shows the results of measuring various physical properties of the obtained composition. Table 3
It is clear that the composition of the present invention has excellent physical properties regardless of the type of antioxidant and the kneading method.

Examples 20 to 25 Compositions were prepared in the same manner as in Examples 2, 6 and 7, except that melamine and diamic acid polyamide were used instead of dicyandiamide.

Table 4 shows the results of measuring various physical properties of the obtained composition. Table 4
It is clear that the composition of the present invention has excellent physical properties regardless of the formaldehyde absorbent and the kneading method.

Examples 26-37 Examples 2, 6-10, 14-16, 20-2 except that the oxymethylene copolymer B obtained in Reference Example 2 is used.
A composition was prepared in the same manner as in 2.

Table 5 shows the results of measuring various physical properties of the obtained composition. Table 5
More clearly, it can be seen that even if the copolymerization component is changed, the same composition as the eyelash can be obtained.

Examples 38 to 42 Compositions were produced in the same manner as in Example 2 except that potassium hydroxide, potassium terephthalate, sodium ethoxide, calcium carbonate and calcium terephthalate were used instead of calcium hydroxide.

Table 6 shows the results of measuring various physical properties of the obtained composition. Table 6
It is clear that the composition of the present invention has excellent physical properties regardless of the type of alkali or alkaline earth metal salt.

<Effects of the Invention> Since the oxymethylene copolymer composition produced by the present invention is excellent not only in melt stability but also in mechanical properties and the like, it is widely used in mechanical mechanism parts, automobile parts, electric / electronic parts and the like. It can be used for various purposes.

Claims (1)

[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. In the presence of at least one type of polymerization catalyst, after bulk polymerization, an alkali metal hydroxide, an alkaline earth metal hydroxide, an alkali metal inorganic acid salt, to the polymer in which a hindered amine is added to deactivate the catalyst. One or more selected from alkaline earth metal inorganic acid salts, alkali metal organic acid salts, alkaline earth metal organic acid salts and alkali metal alkoxides, hindered phenolic antioxidants and formaldehyde by reacting with formaldehyde An oxymethylene copolymer composition prepared by adding and mixing possible reagents.