JPH05156118A - Polyacetal molding - Google Patents

Abstract

PURPOSE:To provide a polyacetal resin molding which is excellent in machinability in, e.g. cutting and punching and retains well-balanced excellent properties such as mechanical strength and toughness. CONSTITUTION:The objective polyacetal molding for cutting is obtained by molding a polyacetal resin composition which has a melt index of 0.01 to 5.0 and comprises a mixture of 100 pts.wt. polyacetal copolymer (A) made by polymerizing 99.85-85.0wt.% trioxane, 0.1-10wt.% cyclic ether and/or cyclic formal as comonomer, and 0.05-5wt.% diglycidyl compound, 0.01-5 pts.wt. of at least one compound (B) selected from a nitrogen compound, a fatty acid ester compound, and a metallic compound comprising the hydroxide, an inorganic acid salt or a carboxylic acid salt of an alkali metal or alkaline earth metal, and 0.01-5 pts.wt. hindered phenolic compound (C).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting polyacetal molded product having excellent machinability. More specifically, the main component is a polyacetal copolymer obtained by polymerizing trioxane, cyclic ethers and diglycidyl compounds, excellent machinability such as cutting and punching, and excellent properties such as mechanical strength and toughness. The present invention relates to a molded product made of a polyacetal resin that is held in good balance.

[0002]

BACKGROUND OF THE INVENTION As is well known, polyacetal resins are representative of excellent physical properties such as mechanical properties and electrical properties, or chemical properties such as chemical resistance and heat resistance. As an engineering resin
It has been used in an extremely wide range of fields in recent years. However, with the expansion of fields in which polyacetal resins are used, the properties required for the materials have been subdivided in various ways. One of such properties is machinability. That is, in the field of ultra-precision parts used in precision machinery, etc., the precision of the product cannot be maintained because the dimensions of the molded product change due to molding shrinkage in injection molding, etc. A general method is to obtain an ultra-precision part from a molded product by cutting, but it cannot be said that the conventional molded body made of polyacetal resin has excellent machinability. Extruded products generally have thick shapes such as rods or sheets, but when trying to cut acetal copolymer resin from such extruded products, the hardness of the material is insufficient, so the thread is cut from the cut surface. In some cases, a material having a high hardness may be required because a predetermined accuracy cannot be obtained by pulling. In order to meet this demand, conventionally known is a method of adding an inorganic filler such as calcium carbonate or talc to an acetal copolymer resin. However, even though these conventionally proposed methods can obtain an acetal copolymer resin material having desirable properties in terms of material surface hardness, that is, machinability, on the other hand, mechanical properties, particularly toughness are deteriorated, resulting in assembly of cut products. There are drawbacks such as damage due to stress at the time of cutting or impact such as dropping when handling the material of the cut product, and the polyacetal resin material yellowing due to the alkalinity of the inorganic filler, impairing the appearance as a part. I had one. Furthermore, when extruding a molded product having such a thickness, a stimulating formaldehyde odor is generated, which deteriorates the working environment, and the appearance of a molded product is deteriorated due to the generation of black matter due to a thermal decomposition product. It had processing defects. A method of adding and blending a phenolic antioxidant is known as a means for suppressing thermal decomposition at the time of processing, and although some improvement is recognized, it is insufficient, and at the same time, improvement thereof has been desired.

[0003]

Means for Solving the Problems The inventors of the present invention have made extensive studies as to the development of a polyacetal resin that has solved these drawbacks, and as a result, have identified it as a special polyacetal copolymer obtained by polymerizing a specific monomer. It was found that the above objects can be achieved by using a composition to which the stabilizer of (1) is added and blended, and the present invention has been completed.
That is, the present invention includes (A) (a) 99.85 to 85.0% by weight of trioxane, (b) 0.1 to 10% by weight of a cyclic ether and / or cyclic formal as a comonomer, and (c) 0.05 to 5% by weight of diglycidyl. In 100 parts by weight of a polyacetal copolymer obtained by polymerizing a compound, (B) a nitrogen-containing compound, a fatty acid ester compound and a metal-containing compound consisting of an alkali metal or alkaline earth metal hydroxide, inorganic acid salt or carboxylate salt. A mixture of 0.01 to 5 parts by weight of one or more compounds selected from (1) and (5) 0.01 to 5 parts by weight of (C) hindered phenolic compound, and molded into a polyacetal resin composition having a melt index of 0.01 to 5.0. The present invention relates to a polyacetal molded product for cutting.

The composition used in the polyacetal molded product for cutting according to the present invention will be described in detail below. First, the (a) trioxane and (b) comonomer, which are the main monomers constituting the (A) polyacetal copolymer of the present invention, are well-known substances conventionally used for producing a polyacetal copolymer. That is, trioxane is a cyclic trimer obtained from formaldehyde.

Further, (b) a cyclic ether or a cyclic formal as a comonomer is a compound represented by the following general formula (2).

[0006]

[Chemical 1]

[In the formula, R ³ , R ⁴ , R ⁵ and R ⁶ represent a hydrogen atom, an alkyl group or an alkyl group substituted with a halogen, and may be the same or different. R ⁷ is a methylene group or an oxymethylene group, or a methylene group or an oxymethylene group substituted with an alkyl group or a halogenated alkyl group (wherein p represents an integer of 0 to 3),

[0008]

[Chemical 2]

The sum q represents an integer of 1 to 4).
The alkyl groups have 1 to 5 carbon atoms and 1 to 3 hydrogens may be replaced by halogen atoms, especially chlorine atoms. Examples of such cyclic ether and cyclic formal include epichlorohydrin, ethylene oxide, 1,3-dioxolane, diethylene glycol formal, 1,4-butanediol formal, 1,3-dioxane and propylene oxide. Further cyclic esters such as β-
Also used are propiolactone and vinyl compounds such as styrene or acrylonitrile. Particularly preferred cyclic ethers and cyclic formal are one or more selected from ethylene oxide, dioxolane, trioxepane and 1,4-butanediol formal.

The amount of cyclic ether or cyclic formal used is 0.1 to 10% by weight, preferably 0.3
~ 5% by weight. If the amount is less than 0.1% by weight, the processability and heat stability characteristic of the polyacetal copolymer are insufficient, and if it exceeds 10% by weight, the production itself becomes difficult. Next, the diglycidyl compound (c) of the present invention will be described.

The diglycidyl compound used in the production of the polyacetal copolymer of the present invention is an aliphatic ether having two glycidyl groups at the ends, and preferably the compound represented by the following general formula (3) or (4) is used. Be done.

[0012]

[Chemical 3]

Examples of the diglycidyl compound represented by the above formula (3) or (4) include diethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether,
Examples thereof include butanediol diglycidyl ether, and butanediol diglycidyl ether is particularly preferable. The amount of the diglycidyl compound used is 0.02 to 5.0% by weight, preferably 0.1 to 3.0% by weight. 0.02% by weight
When the amount is smaller, the excellent machining properties, which is the object of the present application, hardly appears, and when the amount is more than 5.0% by weight, an excessive crosslinking reaction or the like occurs during polymerization, which makes the production itself difficult.
In addition, the processability and mechanical strength of the polymerized product are significantly reduced, which is not preferable.

In the polymerization of the polyacetal copolymer (A) of the present invention, a low molecular weight acetal compound represented by the following general formula (1) is used in order to control the molecular weight in addition to the above-mentioned constituents.
(d) R ¹ O (CH ₂ O) _n R ² (1) [where n is an integer of 1 to 10 and R ¹ and R ² have 1 to 5 carbon atoms]
And R ¹ and R ² may be the same or different.]. The low molecular weight acetal compound (d) represented by the formula (1) is methylal,
Methoxymethylal, dimethoxymethylal, trimethoxymethylal, oxymethylenedi-n-butyl ether and the like can be mentioned, with preference given to methylal.

The amount of the substance (d) added is 0 to 0 depending on the required molecular weight (melt viscosity) of the polyacetal copolymer.
Adjust within 1000ppm.

The polyacetal copolymer may be polymerized in accordance with the well-known trioxane copolymer. That is, as the catalyst, a cation active catalyst is generally used. Specific examples of such catalysts include Lewis acids, particularly halides of boron, tin, titanium, phosphorus, arsenic and antimony, such as boron trifluoride, tin tetrachloride, titanium tetrachloride, phosphorus pentachloride, pentachloride. Compounds such as phosphorus fluoride, arsenic pentafluoride and antimony pentafluoride, and complex compounds or salts thereof, protic acids such as trifluoromethanesulfonic acid, perchloric acid, esters of protic acids, especially perchloric acid and lower aliphatic alcohols. An ester of perchloric acid (for example, tertiary butyl ester), an anhydride of a protic acid, particularly a mixed anhydride of perchloric acid and a lower aliphatic carboxylic acid (for example, acetylperchlorate), or an isopoly acid, a heteropoly acid (for example, Phosphomolybdic acid), or triethyloxonium hexafluorophosphate, triphenylmethyl Sa fluoro Aruze diisocyanate, acetyl hexafluoro borate and the like. Among them, boron fluoride or a coordination compound of boron fluoride and an organic compound (for example, ethers) is the most general and suitable. The polymerization reaction may be batch type, continuous type, or any of solution polymerization, melt bulk polymerization, etc., but a method of using a liquid monomer to obtain a solid powdery bulk polymer as the polymerization proceeds It is common. In this case, an inert liquid medium may coexist if necessary. As a polymerization device, a reaction vessel with a stirrer that is generally used in a batch system can be used, and as a continuous system, a co-kneader, a twin screw type continuous extrusion mixer, a twin screw paddle type continuous mixer, etc. It is possible to use a continuous polymerization apparatus such as that proposed for trioxane. The polymerization temperature is in the temperature range of 64-120 ° C. A relatively low temperature in this range is more desirable. The polymerization time is related to the amount of catalyst and is not particularly limited, but generally 0.5-
A polymerization time of 100 minutes is chosen. After a lapse of a predetermined time, the polymer taken out from the outlet of the polymerization machine is usually a lump or a powder, and a part or all of the unreacted monomer is separated and stabilized through a post-process such as stabilization by a conventional method. A high copolymer can be obtained.

The polyacetal resin copolymer thus obtained surprisingly has mechanical properties which cannot be obtained by a general linear copolymer, and the polyacetal resin copolymer as it is as it is without adding a known inorganic filler or the like. Even when used, it exhibits high surface hardness generally required for machining such as cutting and punching, improves mechanical strength, and is free from the drawbacks of conventional resins containing an inorganic filler and the like, and is suitable as a material for machining. It is a characteristic of the present invention that it is not known at all that the polyacetal copolymer exhibits such characteristics. The resin of the present invention can be used as a mixture with a linear polyacetal homopolymer or a polyacetal copolymer in which most of the main chain is an oxymethylene chain as long as the object is not impaired.

Next, in the present invention, the component (B) is represented by a group consisting of a nitrogen-containing compound, a fatty acid ester compound and an alkali metal or alkaline earth metal hydroxide, inorganic acid salt or carboxylate salt. One or more compounds selected from metal-containing compounds are used. Here, the nitrogen-containing compound means a homologous or copolymerized polyamide such as nylon 12, nylon 6/10, nylon 6/66/610, a substituted polyamide having a methylol group, a nylon salt, or a compound from caprolactam, or caprolactone or caprolactam. Polyamides such as polyesteramide synthesized from the combination with, polyaminotriazole, oxalic acid hydrazide, adipic acid hydrazide, dicarboxylic acid dihydrazide such as sebacic acid hydrazide, a heat condensate synthesized by heating from urea, urea and diamines A nitrogen-containing condensation polymer synthesized from
Urea heating condensates synthesized by heating urea, uracils, cyanoguanidines, dicyandiamide, guanamine (2,4-diamino-sym-triazine), melamine (2,
4,6-triamino-sym-triazine), N-butylmelamine, N-phenylmelamine, N, N-diphenylmelamine, N, N-diallylmelamine, N, N ', N''-triphenylmelamine, N, N ', N''-trimethylolmelamine, benzoguanamine (2,4-diamino-6-phenyl-sym-triazine), 2,4-diamino-6-methyl-sym-triazine, 2,4-diamino-6- Butyl-sym-triazine, 2,4-diamino-6-benzyloxy-sym-triazine, 2,4-diamino-6-butoxy-sym-triazine, 2,4-diamino-6-cyclohexyl-sym-triazine, 2 , 4-Diamino-6-chloro-sym-triazine, 2,4-diamino-6-mercapto-sym-triazine, 2,4-dioxy-6-amino-sym-triazine (amelide), 2-oxy-4, 6-diamino-sym-
Triazine (amelin), N, N, N ′, N′-tetracyanoethylbenzoguanamine and the like can be mentioned. The nitrogen-containing compound is preferably one selected from melamine or a melamine derivative and dicarboxylic acid dihydrazide, more preferably melamine and / or dicarboxylic acid dihydrazide.

Next, the fatty acid ester compound used in the present invention means at least one saturated or unsaturated fatty acid containing 12 to 32 carbon atoms and a multiplicity of glycerol, diglycerol, pentaerythritol, sorbitan, ethylene glycol and the like. It is derived from a polyhydric alcohol. Fatty acids used for preparing the fatty acid ester compound include lauric acid, tridecylic acid, myristic acid, pentadecyl acid, palmitic acid, stearic acid, nonadecyl acid, behenic acid and naturally occurring fatty acids containing these components or those. Is a mixture of. Of these fatty acid ester compounds, fatty acid esters derived from a fatty acid selected from palmitic acid, stearic acid and behenic acid and a polyhydric alcohol selected from glycerol or sorbitan are preferred. Examples of preferred fatty acid ester compounds include glycerin monostearate,
Examples thereof include glycerin distearate, glycerin monobehenate, sorbitan monostearate and sorbitan monobehenate.

Next, the metal-containing compound consisting of an alkali metal or alkaline earth metal hydroxide, inorganic acid salt or carboxylate will be described. That is, as the alkali metal, lithium, sodium, potassium, etc., as the alkaline earth metal, magnesium, calcium, barium, etc., and as the inorganic acid salt, respective salts such as carbonic acid, phosphoric acid, silicic acid, carboxylic acid. Examples of the salt include salts of higher (C _12-32 ) fatty acids such as oxalic acid, malonic acid, succinic acid, stearic acid, and behenic acid, and substituted higher fatty acids having a substituent such as a hydroxyl group. Preferred are hydroxides, carbonates and carboxylates of calcium, magnesium and lithium, more preferably carboxylates. Examples of particularly preferable metal-containing carboxylates include calcium stearate, calcium 12-hydroxystearate, calcium behenate and the like.

These compounds (B) may be used alone or in combination of two or more kinds. Above all
As the component (B), it is preferable to use a nitrogen-containing compound in combination with a fatty acid ester compound and / or a metal-containing compound. As a particularly preferred combination of compounds, one or more selected from melamine and dicarboxylic acid hydrazide, and one selected from glycerin monostearate, glycerin distearate, glycerin monobehenate, sorbitan monostearate, and sorbitan monobehenate. And / or a combination of stearic acid or behenic acid with a calcium salt is exemplified. The compounding amount of the compound (B) in the composition of the present invention is (A) the polyacetal copolymer 10
0.01-5 parts by weight, preferably 0.03-2, relative to 0 parts by weight
Parts by weight, more preferably 0.05 to 1.0 parts by weight. If the amount is less than 0.01 part by weight, the effect of improving the thermal stability is not sufficiently exhibited, and if it exceeds 5 parts by weight, the compound itself tends to precipitate on the surface of the composition or the molded article, which is not preferable. The component (B) is combined with the hindered phenolic compound (C) in the polyacetal copolymer to suppress the decomposition of the polyacetal copolymer, and also has the effect of trapping formaldehyde generated by decomposition. Therefore, it is presumed that the generation of decomposition gas at the time of molding is suppressed as much as possible and the generation of black matter due to thermal decomposition and the like is reduced.

Next, as the hindered phenol compound (C) used in the present invention, 2,2'-methylenebis (4methyl-6-t-butylphenol) and 1,6-hexanediol-bis [3- (3,5-di-t-butyl-4
-Hydroxyphenyl) propionate], pentaerythrityl tetrakis [3- (3,5-di-t-butyl-4-]
Hydroxyphenyl) propionate], triethylene glycol-bis- [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,3,
5-Trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxy-benzyl) benzene, n-octadecyl-3- (4'-hydroxy-3 ', 5'-di- t-butylphenol) propionate, 4,4'-methylenebis (2,6-
Di-t-butylphenol), 4,4'-butylidene-bis- (6-t-butyl-3-methyl-phenol), 2,2 '
-Thiodiethyl-bis- [3- (3,5-di-t-butyl-
4-Hydroxyphenyl) propionate], distearyl-3,5-di-t-butyl-4-hydroxybenzylphosphonate, 2-t-butyl-6- (3-t-butyl-5-methyl-2-hydroxybenzyl) ) -4-Methylphenyl acrylate, N, N'-hexamethylenebis (3,5
-Di-t-butyl-4-hydroxy-hydrocinnamamide), at least one kind or two or more kinds can be used. Among these, 1,6-hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], pentaerythrityl tetrakis [3- (3,5-di-t-butyl) -4-hydroxyphenyl) propionate], triethylene glycol-bis- [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], N, N'-hexamethylenebis (3,5- Di-t-butyl-4-hydroxy-hydrocinnamamide) is a particularly preferred substance. The amount of the hindered phenolic compound (C) added and blended in the present invention is (A) 100 parts by weight of the polyacetal copolymer,
It is 0.01 to 5 parts by weight, preferably 0.1 to 3 parts by weight. (C)
If the added amount of the component is too small, a sufficient effect cannot be obtained, and if the added amount is too large, the effect of heat stability reaches saturation, and rather bleeding occurs, which is not preferable.

Although the method for molding the polyacetal resin composition of the present invention for cutting is arbitrary, it is preferably extrusion. Also, the polyacetal resin composition used for extrusion processing has a standard load (ASTM D-1238) of 2.16 kg at 190 ° C.
-57T) The melt index (hereinafter abbreviated as MI) under
It is in the range of 0.01 to 5.0 (g / 10 minutes), preferably 0.05 to 3.0. Resins having an MI of less than 0.01 are difficult to produce, and resins having an MI of more than 5.0 are not preferable because it is difficult to produce a molded product by extrusion. Furthermore,
Preferred as the polyacetal molded article of the present invention,
It has a Vickers hardness of 20 Hv or more at a load of 1 g according to the measurement method described later.

Since the resin of the present invention imparts its physical properties depending on the intended use, various known additives such as colorants, lubricants, release agents, nucleating agents, antistatic agents, etc. Of course, it is also possible to use the above-mentioned surfactant, different polymer, organic improver and the like as a composition blended during the polymerization or after the polymerization and before the molding.

[0025]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Production Example 1 (Polyacetal copolymer A-1)
The composition of two circles with an inner diameter of 80 mm partially overlaps and the effective length
A barrel with a jacket that passes the heat medium to the outside of 1.3 m,
A continuous mixing reactor consisting of two rotating shafts with a number of intermeshing paddles inside was used for the jacket
Passing hot water at 80 ℃, rotate two rotating shafts in different directions at a speed of 100 rpm. At one end, trioxane 96.6% by weight, dioxolane 3.0% by weight, butanediol diglycidyl ether 0.3% by weight, methylal 0.1% by weight. It was continuously supplied at a rate of 10 kg / h, and at the same time, a predetermined amount of a solution of boron trifluoride dibutyl etherate in cyclohexane was continuously added for copolymerization, and the reaction mixture discharged from the other end. Immediately with 0.1% triethylamine
The polymerization catalyst was deactivated by throwing it in water containing. Next, the polymer was washed with acetone and then air-dried to stabilize it.
A polyacetal copolymer was obtained. Production Examples 2 to 3 (polyacetal copolymer A-2, A-3
Synthesis of) A polyacetal copolymer was obtained in the same manner as in Production Example 1, except that the amounts of trioxane and butanediol diglycidyl ether used in Production Example 1 were changed as shown in Table 1. Production Example 4 (Synthesis of polyacetal copolymer A-4) Trioxane 97.4% by weight, ethylene oxide 2.0% by weight, butanediol diglycidyl ether 0.5% by weight,
A polyacetal copolymer was obtained in the same manner as in Production Example 1 using 0.1% by weight of methylal. Reference Examples 1 to 3 (polyacetal copolymer A'-1, A '
-2, Synthesis of A'-3) (c) Polymerization was performed in the same manner as in Production Example using (a) trioxane and (b) cyclic ether shown in Table 1 with or without a small amount of diglycidyl compound. After performing the stabilizing step, a substantially linear polyacetal polymer was obtained.

Examples 1 to 8 and Comparative Examples 1 to 5 Various polyacetal copolymers (A) shown in Table 1 were blended with various additives shown in Table 2, mixed and then melted by a twin-screw extruder. The mixture was kneaded to prepare a pelletized composition. The pellets were then used to make the following ratings.
For comparison, one of the components (B) and (C) was not added, and one in which the polyacetal copolymer (A ') was blended with additives as shown in Table 2 Pellets were prepared and evaluated in the same manner as in. The results are shown in Table 2. The test method and measurement method are as follows. (1) Melt index (MI) 190 ° C, 2.16Kg Melt index under standard load (ASTM D-1238-
57T) was measured. (2) Heating weight loss rate The weight loss rate (ppm / min) when 5 g of the material was heated in air at 235 ° C for 45 minutes was shown. (3) Vickers hardness Using a test piece (ASTM D-790, for bending test) with a thickness of about 6.3 mm, using a MHT-1-LS type micro hardness tester (manufactured by Matsuzawa Seiki Co., Ltd.) with a load of 1 g It was measured under the conditions. (4) Machinability A test piece with a thickness of about 6.3 mm (ASTM D-790, for bending test) was used to cut using an electric circular saw (manufactured by Toyo Seiki Co., Ltd.) The mustache length was measured and ranked as follows. A: Mustache length less than 1 mm B: Mustache length not less than 1 mm and less than 3 mm C: Mustache length not less than 3 mm and less than 5 mm D: Mustache length not less than 5 mm (5) Shear strength 100 x 100 x 4 mm flat plate made of SUS with a diameter of 50 mm It was attached to the tip of the cylinder. Using this as a base of a SUS thick plate having a hole with a diameter of 50 mm as a base, the load when the flat plate was punched out was measured using a Tensilon manufactured by Orientec, and the shear strength was calculated by the following formula. Shear strength = L / 50π · t L; Load 50π; Punching circumference t; Plate thickness

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

As is apparent from the above description and Examples, a polyacetal copolymer obtained by polymerizing trioxane, a cyclic ether and / or a cyclic formal, and a diglycidyl compound is blended with a specific additive. The molded product for cutting, which is obtained by molding the composition, is preferably in the form of a sheet or a rod in view of the extrudability, the machinability or the application to be used, etc., and especially the polyacetal having an average wall thickness or diameter of 10 mm or more. It is preferably used as a molded body. Further, such a molded product has excellent machinability, particularly characteristics of reducing beards generated during cutting and punching, as compared with those using a conventional polyacetal resin, and a good balance between strength and toughness is maintained. It is extremely preferable as a material for ultra-precision parts manufactured by cutting machining. Therefore, the polyacetal molded product of the present invention is suitable for automobiles, electric / electronic parts, and the like, which require high precision, for example, portable small audio equipment, watches, and mechanical parts related to computers.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area C08K 5/16

Claims (11)

[Claims] 1. A) (a) 99.85 to 85.0% by weight of trioxane, (b) 0.1 to 10% by weight of a cyclic ether and / or cyclic formal as a comonomer, and (c) 0.05 to 5% by weight of diglycidyl. In 100 parts by weight of a polyacetal copolymer obtained by polymerizing a compound, (B) a nitrogen-containing compound, a fatty acid ester compound and a metal-containing compound consisting of an alkali metal or alkaline earth metal hydroxide, inorganic acid salt or carboxylate salt. A mixture of 0.01 to 5 parts by weight of one or more compounds selected from (1) and (5) 0.01 to 5 parts by weight of (C) hindered phenolic compound, and molded into a polyacetal resin composition having a melt index of 0.01 to 5.0. Polyacetal molding for cutting. 2. The molded product according to claim 1, which has a Vickers hardness of 20 Hv or more measured by the method described in the text. 3. The polyacetal molded product according to claim 1, wherein the component (A) (b) is one or more selected from ethylene oxide, dioxolane, trioxepane and 1,4-butanediol formal. 4. The polyacetal molded product according to claim 1, wherein the component (A) (c) is an alkylene oxide diglycidyl ether. 5. The polyacetal copolymer (A) is polymerized in the presence of (d) a low molecular weight acetal compound represented by the following general formula (1): The polyacetal molded article according to item 1. R ¹ O (CH ₂ O) _n R ² (1) [where n is an integer of 1 to 10 and R ¹ and R ² have 1 to 5 carbon atoms]
The alkyl groups may be the same or different. ] 6. The nitrogen-containing compound as the component (B) is melamine and / or dicarboxylic acid dihydrazide.
The polyacetal molded product according to any one of 1. 7. The fatty acid ester compound as the component (B) is glycerin monostearate, glycerin distearate,
The polyacetal molded product according to any one of claims 1 to 6, which is one or more of glycerin monobehenate and sorbitan monostearate. 8. The metal-containing compound as the component (B) is calcium stearate, calcium 12-hydroxystearate,
The polyacetal molded product according to any one of claims 1 to 7, which is one or more kinds of calcium behenate. 9. A polyacetal molded body, wherein the molded body according to claim 1 is in the form of a sheet or a rod. 10. A molded product according to any one of claims 1 to 9, which has an average wall thickness or a diameter of 10 mm or more. 11. A polyacetal mechanical component for an electric, electronic or automobile machined from the molded body according to any one of claims 1 to 10 by machining.