JP2005336304A - Polyacetal resin composition and molded article composed of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyacetal resin composition, excellent in heat stability, in which the amount of formaldehyde generated from products is remarkably reduced and occurrence of mold deposit in molding is suppressed. <P>SOLUTION: The polyacetal resin composition is obtained by compounding (A) 100 pts. wt. polyacetal resin with (B) 0.01-5 pts. wt. hydrazide compound, (C) 0.001-1 pt. wt. imide compound and (D) 0.01-5 pts. wt. hindered phenol. The polyacetal resin composition is suitably used for furniture, building materials, interiors, etc., as measures against so-called sick house syndrome. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyacetal resin composition and a molded article comprising the same. More specifically, the present invention relates to a polyacetal resin composition having excellent thermal stability, suppressing the amount of formaldehyde generated from pellets and molded products, and having little mold deposit during molding, and a molded product comprising the same.

  Polyacetal resin is widely used as an engineering plastic having balanced mechanical properties and good self-lubricating properties and electrical properties in various mechanical and electrical components. However, since the main raw material of the monomer is formaldehyde, polyacetal resin generates formaldehyde in a very small amount due to a slight thermal decomposition reaction in the thermal history during polymerization or molding, which only deteriorates the working environment. In addition, mold deposits (mold deposits) are generated during molding, contaminating the molds, causing molding defects, and reducing productivity. In addition, it is difficult to completely eliminate formaldehyde from the final product, and there is concern about the impact on sick house syndrome and the like. The indoor formaldehyde concentration guideline value from the Ministry of Health, Labor and Welfare is defined as 0.08 ppm, and as a measure against sick house syndrome, it is required to further reduce the amount of formaldehyde generated from the current level. For this purpose, a polyacetal resin having a low formaldehyde generation amount is desirable.

  Conventionally, in order to suppress the amount of formaldehyde generated in pellets and molded articles containing a polyacetal resin, it has been proposed to add various additives to the polyacetal resin. For example, a resin composition containing a hindered phenol-based antioxidant and a carbon black and a borate of a nitrogen-containing compound such as dihydrazide (Patent Document 1) or hydrazide previously treated with a polymer (Patent Document 2), or As a formaldehyde adsorbent, a novel compound 1,2,3,4-butanetetracarboxylic acid hydrazide (Patent Document 3) Deodorant (Patent Document 4) containing hydrazide and urea or its derivatives in a specific ratio, etc. Is mentioned. However, these have problems such as insufficient suppression of formaldehyde and deterioration of physical properties of molded products, and further, polyacetal resin compositions with reduced formaldehyde generation have been demanded.

JP-A-7-173369 JP 10-36630 A Japanese Patent Laid-Open No. 6-80619 JP 2002-35098 A

  An object of the present invention is to provide a polyacetal resin composition that is excellent in thermal stability, has a greatly reduced amount of formaldehyde generated from a product, and suppresses generation of mold deposits during molding.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have formulated formaldehyde generated from pellets and molded articles by blending a hydrazide compound and an aromatic imide compound together with a sterically hindered phenol into a polyacetal resin. The inventors have found that the amount can be remarkably suppressed and the mold deposit can be reduced, and the present invention has been achieved. That is, the gist of the present invention is that (A) 0.01 to 5 parts by weight of hydrazide compound, (C) 0,001 to 1 part by weight of imide compound and (D) steric hindrance with respect to 100 parts by weight of polyacetal resin (A). It exists in the polyacetal resin composition formed by mix | blending 0.01-5 weight part of phenol, and a molded article consisting thereof.

  The polyacetal resin composition obtained in the present invention is not only excellent in thermal stability, but also suppresses the amount of formaldehyde generated from pellets and molded products, and has a small mold deposit. Therefore, there is no fear of deteriorating the working environment at the time of manufacturing a molded article, and it is extremely useful as a material for automobile interior parts, building material parts used in houses, schools, etc., and electrical parts, especially as a countermeasure against so-called sick house syndrome.

Hereinafter, the present invention will be described in detail.
The polyacetal resin (A) used in the present invention includes an acetal homopolymer having an oxymethylene group (—CH ₂ O—) as a main structural unit, and a copolymer (block polymer) containing at least one structural unit other than the oxymethylene group. And terpolymers and the like. The polyacetal resin may have not only a linear structure but also a branched or crosslinked structure. As structural units other than the oxymethylene group, an oxyethylene group (—CH ₂ CH ₂ O—), an oxypropylene group (—CH ₂ CH ₂ CH ₂ O—), an oxybutylene group (—CH ₂ CH ₂ CH ₂ CH). ₂ O-) and other oxyalkylene groups having 2 to 4 carbon atoms are exemplified, and among them, an oxyethylene group is preferable. Moreover, as content of an oxyalkylene unit structure, 0.1 to 20 weight% is preferable.

The polyacetal resin which has an oxymethylene group (—CH ₂ O—) and an oxyalkylene group having 2 to 4 carbon atoms as a structural unit is an oxymethylene group such as a trimer of formaldehyde (trioxane) or a tetramer (tetraoxane). It is produced by copolymerizing a cyclic oligomer and a cyclic oligomer containing an oxyalkylene group having 2 to 4 carbon atoms such as ethylene oxide, 1,3-dioxolane, 1,3,6-trioxocan, 1,3-dioxepane. Can do. Among these, a copolymer of a cyclic oligomer such as trioxane or tetraoxane and ethylene oxide or 1,3-dioxolane is preferable. In particular, a copolymer of trioxane and 1,3-dioxolane is more preferable.

As the (B) hydrazide compound used in the composition of the present invention, any aliphatic or aromatic hydrazide can be used. (B1) Aliphatic hydrazides include monohydrazides such as propionic acid hydrazide and thiocarbohydrazide; carbodihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, azelaic acid, azelaic acid Examples include sebacic acid dihydrazide, 1,12-dodecanedicarbohydrazide, 1,18-octadecanedicarbohydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, 7,11-octadecadiene-1,18-dicarbohydrazide and the like. (B1) Aliphatic hydrazides preferably have a water solubility (solubility in 100 g H ₂ O at 20 ° C.) of less than 1 g. If the water solubility is 1 g or more, it cannot be said that the effect of reducing the amount of formaldehyde generated is sufficient. The water solubility is more preferably 0.01 g or less. Aliphatic hydrazides having a water solubility of less than 1 g include oxalic acid dihydrazide (0.2 g or less), sebacic acid dihydrazide (0.001 g or less), 1,12-dodecanedicarbohydrazide, 1,18-octadecanedicarbohydrazide ( 0.1 g or less).

  (B2) As aromatic hydrazides, monohydrazides such as salicylic acid hydrazide, 3-hydroxy-2-naphthoic acid hydrazide, p-toluenesulfonyl hydrazide, aminobenzhydrazide, 4-pyridinecarboxylic acid hydrazide; isophthalic acid dihydrazide, terephthalic acid Acid dihydrazide, 1,5-naphthalenedicarbohydrazide, 1,8-naphthalenedicarbohydrazide, 2,6-naphthalenedicarbohydrazide, 4,4'-oxybisbenzenesulfonylhydrazide, 1,5-diphenylcarbonohydrazide, etc. Of dihydrazides. Polyhydrazides such as aminopolyacrylamide and 1,3,5-tris (2-hydrazinocarbonylethyl) isocyanurate can also be used.

Among these hydrazides, (B) hydrazide compounds used in the present invention include terephthalic acid dihydrazide, sebacic acid dihydrazide, 1,12-dodecanedicarbohydrazide, 1,5-naphthalenedihydrazide, 1,8-naphthalenedihydrazide, 2,6-naphthalenedihydrazide and the like are particularly preferable.
The above hydrazide compounds may be used alone or in combination of two or more. The blending amount of the (B) hydrazide compound in the composition of the present invention is 0.01 to 5 parts by weight, preferably 0.03 to 4 parts by weight, and more preferably 0. 05 to 3 parts by weight.

  Specific examples of the (C) imide compound used in the present invention include phthalimide, 3-amino-phthalimide, 4,5-dichlorophthalimide, 4-methylphthalimide, 3-nitrophthalimide, 4-nitrophthalimide, 3, 4,5,6-tetrabromophthalimide, 3,4,5,6-tetrachlorophthalimide, 3,4,5,6-tetrafluorophthalimide, 1,2,3,6-tetrahydrophthalimide, pyromellitic acid diimide, 1,8-naphthalimide, 2,3-naphthalenedicarboximide, 1,4,5,8-naphthalenetetracarboxylic diimide, 4-amino-1,8-naphthalimide, 3,4-pyridinedicarboximide, glutar Imide, 3,3-dimethylglutarimide, 3-methyl-3-ethylglutarimide, 3, -Pentamethylene glutarimide, 3,3-tetramethylene glutarimide, 2,4-dicyano-3-methyl-3-ethyl glutarimide, 2,4-dicyano-3,3-pentamethylene glutarimide, 2,4- Dicyano-3-methyl-3-phenylglutarimide, cycloheximide, maleimide, 2,3-dibromomaleimide, cyclohex-3-ene-1,2-dicarboximide, camphorimide, 9,10-dihydro-9,10- Ethanoanthracene-11,12-dicarboximide and the like can be mentioned.

  Preferably, phthalimide, 3-amino-phthalimide, 4-methylphthalimide, 3-nitrophthalimide, 4-nitrophthalimide, 3,4,5,6-tetrafluorophthalimide, 1,2,3,6-tetrahydrophthalimide, pyro Mellitic acid diimide, 1,8-naphthalimide, 2,3-naphthalenedicarboximide, 1,4,5,8-naphthalenetetracarboxylic diimide, 4-amino-1,8-naphthalimide, 3,4-pyridinedi Carboximide, glutarimide, 3,3-dimethylglutarimide, 3-methyl-3-ethylglutarimide, 3,3-pentamethyleneglutarimide, 3,3-tetramethyleneglutarimide, 2,4-dicyano-3, 3-pentamethylene glutarimide, 2,4-dicyano-3-methyl- - ethyl glutarimide, cycloheximide, maleimide, 2,3-dibromo-maleimide, cyclohex-3-ene-1,2-dicarboximide, camphor imide and the like, particularly phthalimido, pyromellitic diimide is preferably used.

The imide compounds may be used alone or in combination of two or more.
The blending amount of the (C) imide compound in the composition of the present invention is 0.001 to 1 part by weight, preferably 0.003 to 0.7 part by weight, more preferably 100 parts by weight of the (A) polyacetal resin. 0.005 to 0.5 parts by weight.

  The (D) sterically hindered phenol used in the present invention basically refers to a compound having at least one structure represented by the following general formula (1).

(In Formula (1), R ₁ and R ₂ each independently represents a substituted or unsubstituted alkyl group. Furthermore, the meta position and the para position with respect to the hydroxy group are represented by Formula (1). And may be substituted with any substituent containing the structure.

  Specific examples of (D) sterically hindered phenols include 2,2′-methylene-bis (4-methyl-6-tert-butylphenol), 4,4′-methylene-bis (2,6-di-tert-butylphenol). ), 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 3,5-di-tert-butyl-4-hydroxybenzyldimethyl Amine, stearyl-3,5-di-t-butyl-4-hydroxybenzylphosphonate, diethyl-3,5-di-t-butyl-4-hydroxybenzylphosphonate, 2,6,7-trioxa-1-phospha- Bicyclo [2,2,2] -oct-4-yl-methyl-3,5-di-t-butyl-4-hydroxyhydrocinnamate, 3,5-di-t-butyl-4-hydroxypheny 3,5-distearyl-thiotriazylamine, 2- (2-hydroxy-3,5-di-t-butylphenyl) -5-chlorobenzotriazole, 2,6-di-t-butyl-4- Hydroxymethylphenol, 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine, N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), octadecyl-3- (3,5-di-butyl-4-hydroxyphenyl) propionate, 1,6-hexanediol-bis [ 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) Propionate], triethylene glycol-bis [3- (3,5-dimethyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) Propionate] triethylene glycol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,2′-thiodiethyl-bis [3- (3,5-di-t-butyl) -4-hydroxyphenyl) propionate] and the like. Among these, a compound having at least one structure represented by the following general formula (2) is particularly preferable.

(In formula (2), R ₁ and R ₂ have the same meaning as in formula (1)).

  Preferred examples of these include N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide), octadecyl-3- (3,5 -Di-butyl-4-hydroxyphenyl) propionate, 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- (3,5-dimethyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3 -Di-t-butyl-4-hydroxyphenyl) propionate], 2,2′-thiodiethyl-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate]. .

  Further, 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- (3,5-dimethyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- ( 3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3,5-di-t-tyl-4-hydroxyphenyl) propionate], 2,2′- Thiodiethyl-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate].

  These sterically hindered phenols may be used alone or in combination of two or more. The blending amount of (D) sterically hindered phenol in the composition of the present invention is 0.01 to 5 parts by weight, preferably 0.03 to 4 parts by weight, more preferably 0 to 100 parts by weight of (A) polyacetal resin. 0.05 to 3 parts by weight.

  Although this invention composition contains the said (A)-(C) component as an essential, it is preferable to mix | blend (E) amino substituted triazine compound further. The (E) amino-substituted triazine compound used in the composition of the present invention basically means a substituted triazine having a structure represented by the following general formula (3), or an initial weight of the substituted triazine and formaldehyde. It is a condensate.

(In Formula (3), R ₃ , R ₄ and R ₅ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a mercapto group, an alkyl group, an aralkyl group, an aryl group, a cycloalkyl group, an amino group or a substituted group. An amino group, at least one of which represents an amino group or a substituted amino group.

  Specific examples of the amino-substituted triazine compound or the initial polycondensate of the amine-substituted triazine compound and formaldehyde include, for example, guanamine, melamine, N-butylmelamine, N-phenylmelamine, N, N-diphenylmelamine, N, N-diallylmelamine, N, N ′, N ″ -triphenylmelamine, N, N ′, N ″ -trimethylolmelamine, benzoguanamine, 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-dia Roh-6-mercapto -sym- triazine, ammeline (N, N, N ', N'- tetra-cyanoethyl benzoguanamine), or the initial weight condensate thereof with formaldehyde. Among these, melamine, methylol melamine, benzoguanamine, and a water-soluble melamine-formaldehyde resin are particularly preferable.

  One or more amino-substituted triazine compounds may be used in combination. The compounding quantity of the (E) amino substituted triazine compound in this invention composition is 0.01-7 weight part with respect to 100 weight part of (A) polyacetal resin, Preferably it is 0.01-5 weight part.

The composition of the present invention preferably further contains (F) at least one metal-containing compound selected from alkali metal or alkaline earth metal hydroxides, inorganic acid salts, and alkoxides. Examples of inorganic acid salts include carbonates, phosphates, silicates, borates and the like. Examples of the alkoxide include methoxide and ethoxide. (F) The metal-containing compound is preferably an alkaline earth metal hydroxide, inorganic acid salt or alkoxide, and more preferably calcium hydroxide, magnesium hydroxide, potassium hydroxide, calcium carbonate, and magnesium carbonate.
The compounding amount of the metal-containing compound (F) in the composition of the present invention is 0.004 to 5 parts by weight, preferably 0.005 to 5 parts by weight with respect to 100 parts by weight of the (A) polyacetal resin.

  In addition to the above components, the polyacetal resin composition of the present invention can contain known additives and / or fillers as long as the object of the present invention is not impaired. Examples of the additive include a lubricant, an antistatic agent, an ultraviolet absorber, and a light stabilizer. Examples of the filler include glass fiber, glass flake, glass bead, talc, mica, calcium carbonate, potassium titanate whisker, and the like. As other additives, urea compounds, alkylene acrylic compounds, polyether compounds, and the like can be added. Further, pigments and dyes can be added to achieve a desired color.

  Furthermore, it can be prepared by mixing and kneading other resin additives and / or fillers as necessary. The mixing / kneading method is not particularly limited, and includes a method using a conventionally known mixing / kneading apparatus. The kneading is preferably performed at a temperature equal to or higher than the temperature at which the polyacetal resin melts, specifically, at a temperature higher than the flow start temperature of the polyacetal resin as a raw material (generally, 1700C or higher).

  Specifically, for example, for (A) polyacetal resin, (B) hydrazide compound, (C) aromatic imide compound, (D) sterically hindered phenol, if necessary (E) amino-substituted triazine compound, If necessary, (F) a metal-containing compound is added in a predetermined amount at the same time, and if necessary, other resin additives are added, followed by mixing with a tumbler-type blender or the like, and the resulting mixture is uniaxially or A polyacetal resin composition having a desired composition can be obtained by melt-kneading with a twin-screw extruder, extruding into a strand, and pelletizing.

Moreover, the polyacetal resin composition of this invention can obtain a molded article according to the shaping | molding processing method of well-known polyacetal resin. Examples of molded products obtained from the resin composition of the present invention include materials such as pellets, round bars, and thick plates, sheets, tubes, various containers, machines, electricity, automobiles, building materials, and other various parts. It is not something that can be done.
Since the polyacetal resin composition obtained in the present invention is excellent in thermal stability and suppresses the generation of formaldehyde from the product, it is extremely useful for automobile interior parts, building material parts, electrical parts and the like as a countermeasure against so-called sick house syndrome.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the examples shown below unless the gist of the present invention is exceeded.
In addition, the material used by the Example and the comparative example is shown below.

<Material>
* Polyacetal resin: Acetal copolymer using 1,3-dioxolane as a comonomer [comonomer amount is 4.2% by weight with respect to resin, melt index (10.5 g / 10 min)].

* Hydrazide compound-1: 2,6-naphthalenedicarbohydrazide (compound of the following formula).

* Hydrazide compound-2: 1,12-dodecanedicarbohydrazide.

* Aromatic imide compound-1: phthalimide.
* Aromatic imide compound-2: pyromellitic acid diimide.

* Sterically hindered phenol: Triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], trade name “Irganox 245”, manufactured by Ciba Specialty Chemicals.

* Amino-substituted triazine compound: Melamine.

* Metal-containing compound: Magnesium hydroxide.

[Examples 1-8, Comparative Examples 1-10]
With respect to 100 parts by weight of the polyacetal resin, the raw materials were weighed according to the formulation shown in the following Table-1 to Table-3 and mixed by a tumbler type blender. Next, the obtained mixture was melt-kneaded and pelletized with a 40 mmφ single screw extruder (manufactured by Tanabe Plastics Co., Ltd., model: VS-40) at a cylinder temperature of 200 ° C. and a discharge rate of 13 kg / hr to obtain a desired polyacetal resin. After obtaining the composition, a 2 mm thick flat plate was molded at a cylinder temperature of 215 ° C. with an injection molding machine, and the amount of formaldehyde generated in the molded product was measured, and the thermal stability and mold contamination were evaluated by the following methods. .
The results are shown in Table-1 to Table-4. The amount of formaldehyde generated was expressed as a relative value with the value of Comparative Example 1 as a reference (1.00).

<Evaluation method>
(A) Generated formaldehyde amount: 100 mm × 40 mm × 2 mm thickness of the resin composition obtained in the example or the comparative example was molded at a cylinder temperature of 215 ° C. using a PS-40E5ASE molding machine manufactured by Nissei Plastic Industry Co., Ltd. Using a flat plate as a test piece, measurement was performed on the day after molding in accordance with the method described in German Automobile Manufacturers Association Standard VDA275 (automobile interior parts-quantification of formaldehyde emission by the revised flask method).
(i) Put 50 ml of distilled water in a polyethylene container, close the lid with the test piece suspended, and keep it in a sealed state at 60 ° C. for 3 hours.
(ii) Then, after leaving at room temperature for 60 minutes, the test piece is taken out.
(iii) The concentration of formaldehyde absorbed in distilled water in a polyethylene container is measured by an acetylacetone colorimetric method using a UV spectrometer.

(B) Thermal stability: 100 mm x 40 mm x obtained by molding the resin composition obtained in the examples or comparative examples using a PS-40E5ASE molding machine manufactured by Nissei Plastic Industry Co., Ltd. with a cylinder temperature of 215 ° C for 10 minutes. A flat plate having a thickness of 2 mm was used as a test piece, and molding stability at the time of retention (colorability, presence / absence of silver generation) was observed and evaluated according to the following criteria.
A: Thermal stability is very good.
○: Thermal stability is good.
Δ: Thermal stability is normal.
X: Thermal stability is poor.

(C) Mold fouling property: Molding temperature of resin composition obtained in Example or Comparative Example using Sumitomo Heavy Industries, Ltd. mini mat M8 / 7A molding machine and using a drop mold. 500 shots were continuously molded at 230 ° C. and a mold temperature of 35 ° C. After completion, the state of the deposit (mold deposit) on the mold was observed and evaluated according to the following six criteria.

  As is apparent from Tables 1 to 4, all of the compositions of Examples in which a hydrazide compound, an aromatic imide, and a sterically hindered phenol are blended with a polyacetal resin have a reduced amount of generated formaldehyde and have a high thermal stability. In addition to being good, the mold contamination is evaluated as 1 or 2. On the other hand, the composition of the comparative example lacking any one or two of the hydrazide compound, the imide compound, and the sterically hindered phenol has a large amount of formaldehyde generated, or even when the amount of formaldehyde is small, all have poor mold contamination. . The mold contamination properties of the comparative composition are all evaluated as 4 or 5, and as the molding operation is continued, the molded product is contaminated and molding defects are caused.

Claims (4)

  (A) 0.01 to 5 parts by weight of hydrazide compound, (C) 0.001 to 1 part by weight of imide compound, and (D) sterically hindered phenol 0.01 to 5 parts by weight with respect to 100 parts by weight of polyacetal resin. The polyacetal resin composition formed by blending parts.   The polyacetal resin composition according to claim 1, wherein 0.01 to 7 parts by weight of (E) an amino-substituted triazine compound is further blended with 100 parts by weight of (A) polyacetal resin.   (A) 0.004-5 parts by weight of at least one metal-containing compound selected from (F) alkali metal or alkaline earth metal hydroxide, inorganic acid salt or alkoxide is further added to 100 parts by weight of the polyacetal resin. The polyacetal resin composition of Claim 1 or 2 formed by mix | blending.   The molded article formed by shape | molding the polyacetal resin composition in any one of Claims 1-3.