JP2021004337A - Polyacetal resin composition and method for producing the same - Google Patents

Abstract

To provide a polyacetal resin composition that is excellent in weatherability, can suppress the generation of formaldehyde from a molded article to an extremely low level and stably suppresses mold deposit during molding and to provide a method for producing the polyacetal resin composition.SOLUTION: There is provided: a polyacetal resin composition containing at least 100 pts.mass of (A) a polyacetal polymer, 0.03 to 0.30 pt.mass of (B) a hindered phenolic antioxidant, 0.01 to 0.50 pt.mass of (C) an aliphatic carboxylic acid hydrazide, 0.001 to 0.50 pt.mass of (D) a hydantoin compound having two hydrazinocarbonylalkyl groups, 0.001 to 0.30 pt.mass of (E) an alkaline earth metal salt of an aliphatic carboxylic acid, 0.2 to 1.0 pt.mass of (F) a hindered amine compound and 0.2 to 1.0 pt.mass of (G) an ultraviolet absorber in which the total amount of (C) and (D) is 0.03 to 0.55 pt.mass based on 100 pts.mass of the polyacetal polymer (A).SELECTED DRAWING: None

Description

The present invention has a polyacetal resin composition in which the molded product has excellent weather resistance, the amount of formaldehyde generated from the molded product is remarkably suppressed, and the mold deposit during molding is stably suppressed. Regarding things and their manufacturing methods.

Polyacetyl resins have excellent properties, and their molded products are used in a wide range of fields. However, due to their chemical structural characteristics, they are easily decomposed in a heated oxidizing atmosphere or under acidic or alkaline conditions. It has the property of. Therefore, the problem of the polyacetyl resin is to improve the thermal stability and suppress the generation of formaldehyde in the molding process or the molded product. If the thermal stability is low, the polymer is decomposed by heating in a processing process such as extrusion or molding, and deposits (mold deposits) on the mold are generated, and the moldability and mechanical properties are deteriorated. Or

In addition, although the amount of formaldehyde generated from the polyacetyl resin molded product under normal use conditions is extremely small, the generated formaldehyde is chemically active and becomes formic acid by oxidation, which improves the heat resistance of the polyacetyl resin. If it has an adverse effect or is used for parts of electrical and electronic equipment, formaldehyde or its oxide, formic acid, may corrode metal contact parts, and adhesion of organic compounds may cause discoloration or contact failure. is there.

Further, the polyacetyl resin itself is vulnerable to light energy such as sunlight and ultraviolet rays and thermal energy, and when exposed to the atmosphere for a long period of time, cracks occur on the surface of the molded product, causing a decrease in strength.

Therefore, in order to stabilize the polyacetyl resin, an antioxidant and other stabilizers are blended. As antioxidants added to polyacetyl resins, phenol compounds having steric disorders (Hinderd phenol), amine compounds having steric disorders (Hinderdoamine), and the like are known, and others. As stabilizers, melamine, polyamide, alkali metal hydroxide, alkaline earth metal hydroxide and the like are used. Also, antioxidants are usually used in combination with other stabilizers.

However, it is difficult to significantly reduce the formaldehyde generated, particularly the formaldehyde generated from the molded product, only by blending such a general-purpose stabilizer with a polyacetyl resin having a normal formaldehyde quality. Further, in order to solve the above-mentioned problems and reduce the amount of formaldehyde generated, polyacetyl resin compositions containing various compounds have been disclosed.

For example, a technique for using a polyacetal resin having a specific terminal group, a hindered phenolic antioxidant, a hydrazide compound, and an isocyanate compound in combination is disclosed (Patent Document 1).
Further, a technique for coexisting a hindered phenolic antioxidant, a hydrazide compound and an alkaline earth metal salt of a specific carboxylic acid is also disclosed (Patent Document 2).

On the other hand, in order to improve the weather resistance of the polyacetyl resin, for example, a technique of adding and coexisting a hydride-based light stabilizer and a benzotriazole-based ultraviolet light absorber is disclosed (Patent Document 3).
Further, a technique for suppressing the generation of formaldehyde from a molded product and suppressing the exudation of compounded components from the molded product while imparting weather resistance is also disclosed (Patent Document 4).

Japanese Unexamined Patent Publication No. 2009-286874 Japanese Unexamined Patent Publication No. 2006-45489 JP-A-61-36339 Japanese Unexamined Patent Publication No. 2008-7676

According to the techniques disclosed in Document 1, it is possible to reduce the mold deposit during molding of the polyacetyl resin to a considerable level. However, although it is effective in reducing the mold deposit, the actual situation is that the generation of formaldehyde cannot be sufficiently suppressed.

Further, according to the technique disclosed in Document 2, although the effect of suppressing the generation of formaldehyde is exhibited, the effect of suppressing the mold deposit is insufficient, and the molding technique is not stable.
According to the technique disclosed in Document 3, a certain degree of weather resistance can be obtained, but the generation of formaldehyde cannot be suppressed at all.

According to the technique disclosed in Document 4, when a hydrazide compound is used, the effect of suppressing formaldehyde generation is greatly exhibited, and a certain level of weather resistance is maintained. However, the mold deposit suppressing effect was insufficient, and the molding technique was not stable.

An object of the present invention is a polyacetal resin composition having excellent weather resistance, capable of suppressing the generation of formaldehyde from a molded product to an extremely low level, and stably suppressing a mold deposit during molding, and a polyacetal resin composition thereof. The purpose is to provide a manufacturing method.

An object of the present invention has been achieved by:

1. 1. At least 100 parts by mass of the (A) polyacetyl polymer,
(B) Hindered phenolic antioxidant 0.03 to 0.30 parts by mass,
(C) 0.01 to 0.50 parts by mass of aliphatic carboxylic acid hydrazide,
(D) 0.001 to 0.50 parts by mass of a hydantoin compound having two hydradinocarbonylalkyl groups,
(E) Alkaline earth metal salt of aliphatic carboxylic acid 0.001 to 0.30 parts by mass,
(F) Hinder-doamine compound 0.2 to 1.0 parts by mass,
(G) Containing 0.2 to 1.0 parts by mass of an ultraviolet absorber,
A polyacetyl resin composition in which the total amount of the (C) and (D) is 0.03 to 0.55 parts by mass with respect to 100 parts by mass of the (A) polyacetal polymer.
2. 2. The polyacetyl resin composition according to 1 above, wherein the (F) hydride amine compound is a hydride amine compound in which the nitrogen of a piperidine derivative having a steric hindrance group is tertiary.
3. 3. The polyacetyl resin composition according to 1 or 2 above, wherein the (C) aliphatic carboxylic acid hydrazide is sebacic acid dihydrazide.
4. The polyacetyl resin composition according to any one of 1 to 3 above, wherein the alkaline earth metal salt of the (E) aliphatic carboxylic acid is at least one selected from calcium stearate and calcium 12-hydroxystearate.
5. (D) The polyacetyl resin composition according to any one of 1 to 4 above, wherein the hydantoin compound having two hydradinocarbonylalkyl groups is 1,3-bis (hydrazinocarbonoethyl) -5-isopropylhydantoin. ..
6. The (F) hydride amine compound is tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, 1,2,3. 4-Butanetetracarboxylic acid and 1,2,2,6,6-pentamethyl-4-piperidinol and β, β, β', β'-tetramethyl-3,9- (2,4,8,10) -Tetraoxaspiro [5.5] undecane) Selected from condensates with dietaanol, polymers of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidin etanol. The polyacetal resin composition according to any one of 1 to 5 above, which is one or more of the above.
7. The (G) UV absorbers are 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol and N- (2-ethylphenyl)-. The polyacetal resin composition according to any one of 1 to 6 above, which is one or more selected from N'-(2-ethoxyphenyl) oxalic acid diamide.
8. The polyacetyl resin composition according to any one of 1 to 7 above, further containing at least one selected from (H1) fatty acid ester and (H2) polyalkylene glycol.
9. (I) The polyacetyl resin composition according to any one of 1 to 8 above, which comprises 1 to 20 parts by mass of aluminum powder.
10. The method for producing a polyacetyl resin composition according to any one of 1 to 9 above, wherein the polyacetal polymer (A) has trioxane as a main monomer (a) and at least one carbon-carbon bond. One or more selected from the cyclic ether and the cyclic formal having the above is used as a comonomer (b), copolymerized using a heteropolyacid as a polymerization catalyst (c), and then an alkali metal element or an alkaline earth metal. A polyacetal copolymer obtained by adding an elemental carbonate, hydrogen carbonate, carboxylate or hydrate (d) thereof, melt-kneading, and deactivating the polymerization catalyst (c). The method for producing a polyacetyl resin composition according to any one of 1 to 9 above.

According to the present invention, a polyacetyl resin composition and a molded product having excellent weather resistance, capable of suppressing the generation of formaldehyde from the molded product to an extremely low level, and stably suppressing the mold deposit during molding. Is provided.

Hereinafter, the present invention will be described in detail.
<(A) Polyacetal polymer>
The (A) polyacetal polymer used in the present invention may be a homopolymer having an oxymethylene group (-OCH _2- ) as a constituent unit, or a copolymer having another comomomer unit in addition to the oximethylene unit. It may be a coalescence, preferably a copolymer.

Generally, it is produced by copolymerizing formaldehyde or a cyclic compound of formaldehyde as a main monomer, and a compound selected from cyclic ether or a cyclic formal as a comomer, and is usually thermally decomposed (alkali). It is stabilized by removing the unstable portion at the end by hydrolysis or the like.

In particular, trioxane, which is a cyclic trimer of formaldehyde, is generally used as the main monomer. Trioxane is generally obtained by reacting an aqueous formaldehyde solution in the presence of an acidic catalyst, and is purified by a method such as distillation before use. The trioxane used for the polymerization preferably contains as little impurities as possible, such as water, methanol, and formic acid.

As the comonomer, general cyclic ether and cyclic ether, and glycidyl ether compounds capable of forming a branched structure or a crosslinked structure can be used alone or in combination of two or more.

The polyacetal polymer as described above can generally be obtained by adding an appropriate amount of a molecular weight modifier and performing cationic polymerization using a cationic polymerization catalyst. The molecular weight modifier used, cationic polymerization catalyst, polymerization method, polymerization apparatus, deactivation treatment of catalyst after polymerization, end stabilization treatment method of crude polyacetal polymer obtained by polymerization, etc. are based on many documents. It is known, and basically any of them can be used.

Particularly preferable methods for producing the polyacetyl polymer include the following. That is, trioxane is used as the main monomer (a), and one or more selected from cyclic ethers and cyclic formals having at least one carbon-carbon bond is used as the comonomer (b) and used as the polymerization catalyst (c). It is copolymerized using a heteropolyacid, and then a carbonate, a hydrogen carbonate, a carboxylate or a hydrate thereof (d) of an alkali metal element or an alkaline earth metal element is added and melt-kneaded, and the polymerization is carried out. It deactivates the catalyst (c). By using the polyacetyl polymer by this method, the amount of formaldehyde generated from the molded product and the generation of mold deposit during molding can be further reduced.

The heteropolyacid used as the polymerization catalyst (c) is a general term for polyacids produced by dehydration condensation of different kinds of oxygen acids, in which a specific different kinds of elements are present in the center and share oxygen atoms. It has mononuclear or dinuclear complex ions formed by condensation of groups.

Specific examples of the above heteropolyacids include phosphomolybdic acid, phosphotungstic acid, phosphomolybd tungstic acid, phosphomolybd vanadic acid, phosphoribd tongue tungstic acid, lintang tungstic acid, silicate tungstic acid, silicate molybdic acid, and kei. Examples thereof include molybdate tungstic acid and molybdate tungstic acid tovanadic acid. Above all, in consideration of the stability of polymerization and the stability of the heteropolyacid itself, the heteropolyacid is preferably any one or more of silicate molybdic acid, silicate tungstic acid, phosphomolybdic acid and phosphotungstic acid.

The amount of the above-mentioned heteropolyacid used varies depending on the type thereof, and the polymerization reaction can be adjusted by appropriately changing it, but in general, it is 0.05 to 100 ppm (hereinafter, 0.05 to 100 ppm) with respect to the total amount of the monomer to be polymerized. , Mass / mass ppm), preferably 0.1 to 50 ppm.

As the polymerization apparatus, a reaction tank with a stirrer, which is generally used in the batch type, can be used, and as a continuous type, a conider, a twin-screw type continuous extrusion mixer, and a twin-screw paddle type continuous mixing. Machines and other continuous polymerization devices such as trioxane proposed so far can be used, and two or more types of polymerization machines can be used in combination.

The polymerization method is not particularly limited, but as previously proposed, the reaction obtained by sufficiently mixing trioxane, copolymer and heteropolyacid as a polymerization catalyst while maintaining a liquid phase state in advance. If the raw material mixture is supplied to the polymerization apparatus and the copolymerization reaction is carried out, the required amount of catalyst can be reduced, and as a result, it is advantageous to obtain a polyacetal copolymer having a smaller amount of formaldehyde emission, which is more preferable. It is a polymerization method. The polymerization temperature is in the temperature range of 60 to 120 ° C.

In the present invention, when the above-mentioned main monomer (a) and comoma (b) are polymerized to prepare a polyacetyl copolymer, a known chain transfer agent for adjusting the degree of polymerization, for example, methylal, is used. It is also possible to add a linear acetate having a low molecular weight such as.

Further, it is desirable that the polymerization reaction is carried out in a state in which impurities having active hydrogen, for example, water, methanol, formic acid, etc. are substantially not present, for example, in a state where each of these is 10 ppm or less, and for this purpose, these impurities It is desirable to use trioxane, cyclic ether and / or cyclic formal, which are prepared to contain as few components as possible, as the main polymer or comomamer.

An alkali metal element or an alkaline earth metal is added to a polyacetyl polymer (crude polyacetyl polymer) that contains a polymerization catalyst and has an unstable portion at the end thereof, which is obtained by polymerizing as described above. The elemental carbonate, hydrogen carbonate, carboxylate or hydrate (d) thereof is melt-kneaded to deactivate the polymerization catalyst and the polyacetal polymer (crude polyacetal polymer) has incompetence. Stable End groups are reduced and stabilized.

The molecular weight of the (A) polyacetal polymer used in the present invention is not particularly limited, but the weight average molecular weight equivalent to PMMA (polymethylmethacrylate) determined by the SEC (size exclusion chromatography) method is 10,000 to 10,000. It is preferably about 400,000. Further, it is preferable that the melt index (measured at 190 ° C. and a load of 2.16 kg according to ASTM-D1238), which is an index of resin fluidity, is 0.1 to 100 g / 10 minutes, and more preferably 0.5 to 100 g. 80 g / 10 minutes.

It is particularly preferable that the (A) polyacetyl polymer used in the present invention has specific terminal properties. Specifically, the amount of hemiformal terminal groups is 1.0 mmol / kg or less, the amount of formyl terminal groups is 0.5 mmol / kg or less, and the amount of unstable terminal groups is 0.5% by mass or less. Here, the hemiformal terminal group is represented by -OCH ₂ OH, and is also referred to as a hydroxymethoxy group or a hemiacetal terminal group. The formyl terminal group is indicated by -OCHO. The amounts of such hemiformal terminal groups and formyl terminal groups can be determined by ¹ H-NMR measurement, and the specific measurement method can be referred to the method described in JP-A-2001-11143.

The unstable terminal amount means the amount of the portion that is present at the terminal portion of the polyacetyl polymer and is unstable to heat or base and easily decomposed. Such an unstable terminal amount is 45 at 180 ° C. by placing 1 g of a polyacetal polymer in a pressure-resistant airtight container together with 100 ml of a 50% (volume%) metalnol aqueous solution containing 0.5% (volume%) ammonium hydroxide. After heat treatment for 1 minute, the mixture was cooled, opened, and the amount of formaldehyde decomposed and eluted in the obtained solution was quantified and expressed in% by volume with respect to the polyacetyl polymer.

The polyacetal polymer (A) used in the present invention preferably has a hemiformal terminal group amount of 1.0 mmol / kg or less, more preferably 0.6 mmol / kg or less. The amount of formyl terminal groups is preferably 0.5 mmol / kg or less, more preferably 0.1 mmol / kg or less. The amount of unstable terminals is preferably 0.5% by mass or less, more preferably 0.3% by mass or less. The lower limits of the hemiformal terminal group amount, the formyl terminal group amount, and the unstable terminal amount are not particularly limited.

As described above, the polyacetyl polymer (A) having specific terminal properties can be produced by reducing impurities contained in the monomer and the comoma, selecting a production process, optimizing the production conditions thereof, and the like.

As the method for producing the (A) polyacetyl polymer having specific terminal properties satisfying the requirements of the present invention below, for example, the method described in JP-A-2009-286874 can be used. However, the method is not limited to this method.

In the present invention, a polyacetyl polymer having a branched or crosslinked structure may be added to the (A) polyacetal polymer and used, in which case the blending amount is 100 mass by mass of the (A) polyacetal polymer. It is 0.01 to 20 parts by mass, and particularly preferably 0.03 to 5 parts by mass.

<(B) Hindered phenolic antioxidant>
The (B) hindered phenolic antioxidant that can be used in the present invention is not particularly limited, and is, for example, a monocyclic hindered phenol compound (for example, 2,6-di-t-butyl-p-). Cresol, etc.), polycyclic hindered phenol compounds linked by groups containing hydrocarbon groups or sulfur atoms (eg, 2,2'-methylenebis (4-methyl-6-t-butylphenol), 4,4'- Methylenebis (2,6-di-t-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 4,4'-butylidenebis (3-methyl-6) -T-butylphenol), 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, 4,4'-thiobis (3-methyl-) 6-t-butylphenol), etc.), hindered phenol compounds having an ester group or an amide group (eg, n-octadecyl-3- (4'-hydroxy-3', 5'-di-t-butylphenyl) propionate, n-Octadecyl-2- (4'-hydroxy-3', 5'-di-t-butylphenyl) compound, 1,6-hexanediolbis [3- (3,5-di-t-butyl-4-) Hydroxyphenyl) propionate], triethylene glycol bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] (also known as: ethylenebis (oxyethylene) bis [3- (3- (5- (5-) 5-) t-Butyl-4-hydroxy-m-tryl) propionate]), pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 3,9-bis {2-[ 3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5.5] undecane, 2- t-butyl-6- (3'-t-butyl-5'-methyl-2'-hydroxybenzyl) -4-methylphenylacrylate, 2- [1- (2-hydroxy-3,5-di-t-) Pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate, di-n-octadecyl-3,5-di-t-butyl-4-hydroxybenzylphosphonate, N, N'-hexamethylenebis (3) , 5-Di-t-butyl-4-hydroxy-dihydrocinnamamide), N, N'-ethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionamide], N, N'-tetramethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) Propionamide], N, N'-hexamethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionamide], N, N'-ethylenebis [3- (3-t-) Butyl-5-methyl-4-hydroxyphenyl) propionamide], N, N'-hexamethylenebis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionamide], N, N' -Bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine, N, N'-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) Propionyl] hydrazine, 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris (4-t-butyl-3-hydroxy-2, 6-Dimethylbenzyl) isocyanurate and the like are exemplified.

In the present invention, at least one or two or more selected from these antioxidants can be used.

The content of the (B) hindered phenol-based antioxidant in the present invention is 0.03 to 0.30 parts by mass with respect to 100 parts by mass of the (A) polyacetal polymer. If the blending amount is less than this amount, the effect is insufficient, and if it is more than this amount, the weather resistance is deteriorated due to the antagonistic action with the hydride amine compound.

<(C) Aliphatic carboxylic acid hydrazide>
Examples of the (C) aliphatic carboxylic acid hydrazide used in the present invention include adipic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, stearic acid hydrazide and the like. Preferred is sebacic acid dihydrazide, which can capture formaldehyde and can significantly suppress the originally generated mold deposit by using it in combination with a hydantoin compound having a hydrazide group.

In the present invention, the amount of (C) added is 0.01 to 0.50 parts by mass, preferably 0.02 to 0.30 parts by mass with respect to 100 parts by mass of the polyacetyl polymer (A). is there.

<(D) Hydantoin compound having two hydradinocarbonylalkyl groups>
The hydrandin compound having two hydradinocarbonylalkyl groups (D) of the present invention (hereinafter, may be abbreviated as hydrandin compound) includes 1,3-bis (hydrazinocarbonoethyl) hydrandin and 1,3-bis (hereinafter, may be abbreviated as hydrandin compound). Hydradinocarbonoethyl) -5-methylhydrantine, 1,3-bis (hydrazinocarbonoethyl) -5,5-dimethylhydranthin, 1,3-bis (hydradinocarbonoethyl) -5-isopropylhydrantin, etc. At the 5-position of hydantin, there are 1 or 2 substituents (a linear or branched alkyl group having 1 to 6 carbon atoms such as a methyl group, and an allyl group having 6 to 10 carbon atoms such as a phenyl group). Etc.), and the two substituents at the 5-position may form a ring together with the carbon atom at the 5-position. Preferably 1,3-bis (hydrazinocarbonoethyl) -5-isopropyl hydantoin is used.

The (D) hydantoin compound of the present invention captures formaldehyde and suppresses mold deposits when used in combination with the (C) aliphatic carboxylic acid hydrazide of the present invention. In particular, the effect is great when used in combination with sebacic acid dihydrazide.

In the present invention, the amount of the (D) hydantoin compound added is 0.001 to 0.50 parts by mass, preferably 0.01 to 0.30 parts by mass, based on 100 parts by mass of the (A) polyacetal polymer. Is.

Further, in the present invention, the effect of the present invention can be obtained if both (C) an aliphatic carboxylic acid hydrazide and (D) a hydantoin compound are contained, but the total amount is 100 parts by mass of the (A) polyacetal polymer. On the other hand, it is preferably 0.03 to 0.55 parts by mass. The content mass ratio of (C) and (D) is preferably (C) :( D) = 10: 90 to 99: 1.

<(E) Alkaline earth metal salt of aliphatic carboxylic acid>
The aliphatic carboxylic acid constituting the alkaline earth metal salt of the (E) aliphatic carboxylic acid of the present invention may be a saturated aliphatic carboxylic acid or an unsaturated aliphatic carboxylic acid. Examples of such an aliphatic carboxylic acid include a monovalent or divalent aliphatic carboxylic acid having 10 or more carbon atoms, for example, a monovalent saturated aliphatic carboxylic acid having 10 or more carbon atoms [capric acid, lauric acid, myristic acid]. , Pentadecylic acid, palmitic acid, stearic acid, araquinic acid, bechenic acid, montanic acid and other 10-34 saturated aliphatic carboxylic acids (preferably 10-30 saturated aliphatic carboxylic acids)], 10 carbon atoms The above monovalent unsaturated aliphatic carboxylic acid [10-34 unsaturated aliphatic carboxylic acid having 10 to 34 carbon atoms such as oleic acid, linoleic acid, linolenic acid, arachidonic acid, and erucic acid (preferably 10 to 30 unsaturated carbon atoms). Saturated aliphatic carboxylic acid), etc.], divalent aliphatic carboxylic acid with 10 or more carbon atoms (dibasic aliphatic carboxylic acid) [divalent carbon such as sebacic acid, dodecanedioic acid, tetradecanedioic acid, tapsiaic acid, etc. Number 10-30 saturated aliphatic carboxylic acid (preferably divalent 10 to 20 saturated aliphatic carboxylic acid), etc.], divalent unsaturated aliphatic carboxylic acid having 10 or more carbon atoms [decenoic acid, dodeceneni Examples thereof include a divalent aliphatic carboxylic acid having 10 to 30 carbon atoms (preferably a divalent unsaturated aliphatic carboxylic acid having 10 to 20 carbon atoms) such as an acid.

Further, in the above-mentioned aliphatic carboxylic acid, a part of the hydrogen atom is substituted with a substituent such as a hydroxyl group, and the aliphatic carboxylic acid having one or a plurality of hydroxyl groups in the molecule (for example, 12-hydroxy). Hydroxysaturated aliphatic carboxylic acids such as stearic acid) having 10 to 26 aliphatic carbon atoms are also included, and aliphatic carboxylic acids having slightly different carbon atoms depending on the accuracy of purification are also included.

In the present invention, as the alkaline earth metal, calcium and magnesium are preferable, and calcium is particularly preferable. Alkaline earth metal salts of particularly preferred aliphatic carboxylic acids are calcium stearate and calcium 12-hydroxystearate.

The amount of the alkaline earth metal salt of the aliphatic carboxylic acid added to the polyacetyl resin composition is 0.001 to 0.30 parts by mass with respect to 100 parts by mass of the (A) polyacetyl polymer. It is preferably 0.01 to 0.25 parts by mass.

<(F) Hinder-doamine compound>
The hindered amine compound used in the present invention is not particularly limited, and a hindered amine compound in which the nitrogen of the piperidine derivative having a steric hindrance group such as a methyl group on the adjacent carbon is secondary or tertiary is preferably used. A hindered amine compound in which the nitrogen of the piperidine derivative having a sterically hindered group is tertiary is particularly preferably used.

As the hindered amine stabilizer in which the nitrogen of the piperidine derivative having a sterically disordering group used in the present invention is secondary, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, 1,2,3 , 4-Butanetetracarboxylic acid and 2,2,6,6-tetramethyl-4-piperidinol and β, β, β', β'-tetramethyl-3,9- (2,4,5,10-tetra) Oxaspiro [5.5] undecane) -condensate with diethanol, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate, 1,2, Examples thereof include a condensate of 3,4-butanetetracarboxylic acid, 2,2,6,6-tetramethyl-4-piperidinol and tridecyl alcohol.

Examples of the hydride amine compound in which the nitrogen of the piperidine derivative having a sterically disordering group used in the present invention is tertiary includes bis (1,2,2,6,6-pentamethyl-4-piperidyl) adipate and bis. (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl sepate and other aliphatic di or tricarboxylic acids-bis or tripiperidyl esters (2-20 aliphatic dicarboxylic acids) Bispiperidyl ester, etc.), N, N', N'', N'''-tetrakis- (4,6-bis- (butyl- (N-methyl-2,2,6,6-tetramethylpiperidine-4) -Il) amino) -triazine-2-yl) -4,7-diazadecan-1,10-diamine, dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidine ethanol , Bis (2,2,6,6-tetramethyl-1- (octyloxy) -4-piperidinyl) ester, bis (1,2,2,6,6-pentamethyl-4-piperidyl) ) [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butylmaroneto, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sevacate, Methyl-1,2,2,6,6-pentamethyl-4-piperidyl sevacate, tetrakis (1,2,2,6,6-pentamethyl-4-piperidinyl) 1,2,3,4-butanetetra Carboxylate, a condensate of 1,2,3,4-butanetetracarboxylic acid, 1,2,2,6,6-pentamethyl-4-piperidinol and tridecylalcor, 1,2, 3,4-Butanetetracarboxylic acid and 1,2,2,6,6-pentamethyl-4-piperidinol and β, β, β', β'-tetramethyl-3,9- (2,4,8) , 10-Tetraoxaspiro [5.5] undecane) -condensate with dietanol, peroxidized 4-butylamino-2,2,6,6-tetramethylpiperidine and 2,4,6-trichloro Reaction products with -1,3,5-triazine and cyclohexane, N, N'-ethane-1,2-diylbis (1,3-propanediamine), 1- [2- {3- (3,5) -Di-t-butyl-4-hydroxyphenyl) propionyloxy} ethyl] -4- {3- (3,5-di-t-butyl-4-hirodoxyphenyl) propionyloxy} -2,2,6 , 6-Tetramethylpiperidine and the like.

Particularly preferred are tetrakis (1,2,2,6,6-pentamethyl-4-piperidinyl) 1,2,3,4-butanetetracarboxylate, 1,2,3,4-butanetetracarboxylic acid. Acid and 1,2,2,6,6-pentamethyl-4-piperidinol and β, β, β', β'-tetramethyl-3,9- (2,4,5,10-tetraoxaspiro] 5.5] Examples include a condensate with undecane) -dietanol and a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidine etanol.

In the present invention, the amount of the (F) hydride amine compound added is 0.2 to 1.0 parts by mass, preferably 0.4 to 0 parts by mass, based on 100 parts by mass of the (A) polyacetyl polymer. It is 0.8 parts by mass.

(F) If the blending amount of the hindered amine compound is too small, a polyacetyl resin composition having excellent weather resistance cannot be obtained, and conversely, if the blending amount is too large, the mechanical properties are deteriorated. Problems such as poor appearance due to exudation occur.

<(G) UV absorber>
Examples of the ultraviolet absorber of the present invention include benzotriazol-based compounds and oxalic acid anilide-based compounds, and these light stabilizers can be used alone or in combination of two or more.

Examples of the benzotriazol-based compound include 2- (2H-benzotriazol-2-yl) -p-cresol and 2- (2H-benzotriazol-2-yl) -4,6-bis (1-). Methyl-1-phenylethyl) phenol, 2- [5-chloro (2H) -benzotriazol-2-yl) -4-methyl-6- (tert-butyl) phenol, 2,4-di -Tert-Butyl-6- (5-chlorobenzotriazol-2-yl) phenol, 2- (2H-benzotriazo-l-2-yl) -4,6-di-tert-pentylpheno- , 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenyl, 2- (2'-hydroxy-3', 5'-di -Benzotriazols having a hydroxyl group such as -isoamylphenyl) benzotriazol and an alkyl (alkyl having 1 to 6 carbon atoms) group substituted aryl group 2- [2'-hydroxy-3', 5'-bis ( α, α-Dimethylbenzyl) Phenyl] Bentriazols 2- (2'-hydroxy-4'-octoxyphenyl) having a hydroxyl group such as benzotriazol and an aralkyl (or allyl) group-substituted allyl group ) Examples thereof include benzotriazols having a hydroxyl group such as benzotriazol and an alkoxy (alkoxy of C1-12) group-substituted allyl groups.

These benzotriazole compounds can be used alone or in combination of two or more.

Among these benzotriazol compounds, 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol and 2- (2H-benzotriazo-) Lu-2-yl) -4,6-di-tert-pentylphenol, 2- (2H-benzotriazo-lu-2-yl) -4- (1,1,3,3-tetramethylbutyl) pheno -Lu is preferable.

Examples of the oxalic acid anilide compound include N- (2-ethylphenyl) -N'-(2-ethoxy-5-t-butylphenyl) oxalic acid diamide and N- (2-ethylphenyl) -N'-(2). Examples thereof include −ethoxyphenyl) oxalic acid diamides and oxalic acid diamides having an aryl group optionally substituted on the nitrogen atom. The oxalic acid anilide compound can be used alone or in combination of two or more.

In the present invention, the amount of the (G) ultraviolet absorber added is 0.2 to 1.0 parts by mass with respect to 100 parts by mass of the (A) polyacetyl polymer. It is preferably 0.4 to 0.8 parts by mass. (G) If the amount of the ultraviolet absorber is too small, a polyacryl resin composition having excellent weather resistance cannot be obtained. On the contrary, if the amount of the ultraviolet absorber is too large, the mechanical properties are deteriorated and stains are formed. Problems such as poor appearance due to putting out occur.

<(H1) fatty acid ester and (H2) polyalkylene glycol>
The fatty acids that are constituents of the (H1) fatty acid ester of the present invention are one or more saturated or unsaturated fatty acids, and examples of such fatty acids include acetic acid, propionic acid, butyric acid, caproic acid, and caprin. Acids, undecylic acid, hibaric acid, capricic acid, lauric acid, tridecic acid, isotridecic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecic acid, stearic acid, 12-hydroxystearic acid, nonadecanic acid, araquinic acid, behenic acid, There are gnoseric acid, serotic acid, heptacosanoic acid, montanic acid, melisic acid, laxelic acid, lanic acid, ellaic acid, linoleic acid, linolenic acid, arachidonic acid, setreic acid, eca acid and the like, preferably having 12 carbon atoms. These are the above fatty acids.

On the other hand, as the alcohol which is a constituent component of the (H1) fatty acid ester, either monovalent alcohol (for example, stearyl alcohol) or multivalent alcohol can be used, but the polyvalent alcohol can be used. It is preferably le. Examples of the polyvalent alcohol include C2-6 alkylene glycols such as ethylene glycol, propylene glycol and tetomethylene glycol, diethylene glycol, glycerin, pentaerythritol and the like.

In addition, poly C2-6 oxyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol, and polyoxyethylene-polyoxypropylene copolymers (random or block copolymers, etc.) , Polyoxyethylene polyoxypropylene glyceryl ether, polyoxyethylene polyoxypropylene monobutyl ether and the like are also mentioned as preferable polyvalent alcohols for constituting (H1) fatty acid ester. ..

More preferred polyoxyalkylene glycols are polymers having oxyethylene units, such as polyethylene glycols, polyoxyethylene polyoxypropylene copolymers and derivatives thereof.

Preferred (H1) fatty acid esters include esters of fatty acids having 12 or more carbon atoms and polyalkylene glycols having an average degree of polymerization of about 20 to 300.

The (H2) polyalkylene glycol includes homopolymers such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polyglycerin, and polyoxyethylene-polyoxypropylene copolymers (random or). At least one selected from a copolymer such as block copolymer) can be used, and polyalkylene glycol having an average degree of polymerization of about 20 to 300 is preferable.

In the present invention, the compounding of the compound selected from (H1) fatty acid ester and (H2) polyalkylene glycol is not essential, but the compounding of these compounds has an effect of promoting the improvement of weather resistance. When the compound (H1 and / or H2) is blended, the blending amount is 0.01 to 5.0 parts by mass, preferably 0.05 to 5.0 parts by mass with respect to 100 parts by mass of the (A) polyacetyl polymer. It is 2.0 parts by mass. When (H1) and (H2) are used in combination, the mass ratio is preferably 90: 10 to 5:95.

<(I) Aluminum powder pigment>
As the metallic pigment used in the present invention, aluminum powder can be preferably used. Further, those obtained by dispersing these in polyethylene resin, polyethylene wax or the like can also be used.

The blending amount of the (I) aluminum powder is 1 to 20 parts by mass, preferably 3 to 10 parts by mass with respect to 100 parts by mass of the (A) polyacetyl polymer. If the blending amount is too small, a polyacetal resin composition having a good color tone cannot be obtained. On the contrary, if the blending amount is too large, problems such as deterioration of mechanical properties and poor appearance may occur. ..
<Other additives>

The polyacetyl resin composition of the present invention may further contain an impact resistance improver, a gloss control agent, a slidability improver, a filler, a colorant, and a nucleus, if necessary, as long as the present invention is not impaired. Mixing one or more kinds of agents, antistatic agents, surfactants, antibacterial agents, antifungal agents, air fresheners, foaming agents, compatibilizers, physical property improving agents (boric acid or its derivatives, etc.), fragrances, etc. Can be done.
<Manufacturing method of polyacetyl resin composition>

The method for producing the polyacetyl resin composition of the present invention is not particularly limited, and it can be prepared by various methods conventionally known as a method for preparing a resin composition. For example, (1) a method of mixing all the components constituting the composition, supplying the mixture to an extruder and melt-kneading the mixture to obtain a pellet-shaped composition, and (2) a part of the components constituting the composition. Residual components are supplied from the main feed port of the extruder and melt-kneaded to obtain a pellet-shaped composition. (3) Pellets having different compositions are once prepared by extrusion or the like, and the pellets are prepared. A method of mixing pellets to adjust the composition to a predetermined composition can be adopted.

In the preparation of the composition using an extruder, it is preferable to use an extruder having one or more devolatilization vent ports, and further, water or water or any place from the main feed port to the volatilization vent port is used. About 0.1 to 10 parts by mass of low boiling point alcohols are supplied to 100 parts by mass of polyacetal resin, and formaldehyde and the like generated in the extrusion process are supplied together with water and low boiling point alcohols from the devolatilization vent port. It is preferable to remove the volatilization. Thereby, the amount of formaldehyde generated from the polyacetyl resin composition and the molded product thereof can be further reduced.

The polyacetyl resin composition of the present invention prepared in this manner is molded by various conventionally known molding methods such as injection molding, extrusion molding, compression molding, vacuum molding, blow molding, foam molding and the like. Can be done.

The present invention also includes recycling of a molded product composed of the polyacetyl resin composition and the colored polyacetyl resin composition according to the above. Specifically, a recycled resin composition obtained by melt-kneading and extruding a molded product made of these resin compositions or a crushed product thereof alone or together with a resin material or molded product having the same or different composition, and these. This is a recycled molded product obtained by melt-kneading a molded product or a pulverized product thereof made of the above resin composition, alone, or together with a resin material or molded product having the same or different composition.

In this way, the recycled resin composition and the recycled molded product prepared by repeating the heat of fusion history also maintain an extremely low level of formaldehyde generation, similarly to the polyacetyl resin composition on which they are based. It is a thing.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto. In addition, all "parts" in Examples and Comparative Examples represent parts by mass. In addition, various characteristics evaluated in Examples and Comparative Examples and their evaluation methods are as follows. The unit of the numerical value shown in Tables 1 and 2 is a mass part.

The various component ratios shown in Tables 1 and 2 were added and mixed, and melt-kneaded with a twin-screw extruder with a vent to prepare a pellet-shaped composition. The components shown in Tables 1 and 2 used in the examples are as follows.

(A) Polyacetal polymer A-1: Using a biaxial paddle type continuous polymerizer, 1,3-dioxolane 3.3% by mass based on all monomers (trioxane and 1,3-dioxolane). , Trioxane added with 1000 ppm of polymerization is continuously supplied, and at the same time, boron trifluoride dibutyl etherate (catalyst concentration: 20 ppm (as boron trifluoride) cyclohexane solution for all polymers) is supplied to the same place. Dioxolane and polymerized.
Immediately after the polymer discharged from the discharge port of the polymerizer, an aqueous solution containing 1000 ppm of triethylamine was added, mixed and pulverized, and stirred. Then, it was centrifuged and dried to obtain a catalyst-inactivated polymer. This polymer is supplied to a twin-screw extruder having a vent port, melt-kneaded at a resin temperature of about 220 ° C., and while vacuum devolatile at the vent port, unstable ends are removed to form a pellet-shaped polymer. Got Then, it was dried to obtain a desired polymer. (Melt index (measured at 190 ° C. and load 2.16 kg): 9 g / 10 minutes)

A-2: Using a twin-screw paddle type continuous polymerization machine, trioxane containing 3.3% by mass of 1,3-dioxolane and 1000 ppm of methylal to all monomers (trioxane and 1,3-dioxolane) was added. It was continuously supplied, and at the same time, phosphotungstate (catalyst concentration: 3 ppm methyl formate solution for all monomers) was supplied and polymerized as a heteropolyacid catalyst at the same place. 20 ppm of sodium stearate is added to the polymer discharged from the discharge port of the polymer, supplied to a twin-screw extruder having a vent port, melt-kneaded at a resin temperature of about 220 ° C., and devolatile under reduced pressure at the vent port. , The catalyst was deactivated and the unstable end was removed to obtain a pellet-shaped polymer. Then, it was dried to obtain a desired polymer. (Melt index (measured at 190 ° C. and load 2.16 kg): 9 g / 10 minutes)

(B) Hindered Phenolic Antioxidant B-1: Ethylene Bis (Oxyethylene) Bis [3- (3- (5-t-Butyl-4-hydroxy-m-trill) Propionate] (IRGANOX245: Made by BASF)
B-2: Pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (IRGANOX 1010: manufactured by BASF)
(C) Aliphatic carboxylic acid hydrazide C-1: Sebacic acid dihydrazide C-2: Adipic acid dihydrazide C-3: Dodecanedioic acid dihydrazide ・ (D) Hydantoin compound D-1: 1,3-bis (hydrazinocarbo) Noethyl) -5-isopropyl hydantoin ("Amicure" VDH: manufactured by Ajinomoto Fine Techno Co., Ltd.)
(E) Alkaline earth metal salt of aliphatic carboxylic acid E-1: Calcium stearate E-2: 12-Calcium hydroxystearate

(F) Hinderdoamine compound F-1: 1,2,3,4-butanetetracarboxylic acid and 1,2,2,6,6-pentamethyl-4-piperidinol and β, β, β', β'-Tetramethyl-3,9- (2,4,8,10-tetraoxaspiro [5.5] undecane) Condensate with dietanol (ADEKA STAB LA-63P: manufactured by ADEKA Corporation)
F-2: Tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate (ADEKA STAB LA-52: manufactured by ADEKA Corporation)
F-3: Condensation of 1,2,3,4-butanetetracarboxylic acid, 1,2,2,6,6-pentamethyl-4-piperidinol and tridecylalkol (adekastab LA-62: Made by ADEKA Corporation)
As described above, the hindered amine compound F-4: bis (2,2,6,6-tetramethyl-4-piperidyl) sevacate (TINUVIN770DF: BASF) in which the nitrogen of the piperidine derivative having a steric hindrance group is tertiary. Manufactured by) A hindered amine compound in which the nitrogen of a piperidine derivative having a steric hindrance group is secondary.

(G) UV absorber G-1: 2- (2H-benzotriazo-l-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol (TINUVIN234: manufactured by BASF)
G-2: N- (2-ethylphenyl) -N'-(2-ethoxy-phenyl) oxalic acid diamide (SanduvorVSU: manufactured by Clariant AG)
(H1) fatty acid ester and (H2) polyalkylene glycol H1-1: polyethylene glycol monostearic acid ester (average degree of polymerization of polyethylene glycol 90) (Nonion S-40: manufactured by Nichiyu Co., Ltd.)
H2-1: Polyethylene glycol (average molecular weight about 8300) (PEG-6000S)
(I) Aluminum powder pigment I-1: Aluminum powder dispersed in polyethylene (70% by mass of aluminum / 30% by mass of polyethylene)

<Evaluation>
The characteristic evaluation items and evaluation methods in the examples are as follows. The results are shown in Tables 3 and 4.

<Evaluation of formaldehyde generation (VOC) from molded products>
Using the polyacetyl resin compositions prepared in Examples and Comparative Examples, a flat plate-shaped test piece (100 mm × 40 mm × 2 mmt) was molded under the following conditions. Two of these flat plate-shaped test pieces were enclosed in a 10 L polyvinyl fluoride sampling bag, degassed, 4 L of nitrogen was added, and heated at 65 ° C. for 2 hours, and then the nitrogen in the sampling bag was adjusted to 0.5 ml / min. 3 L was extracted, and the generated formaldehyde was adsorbed on a DNPH (2,4-dinitrophenylhydrazine) collecting tube (Sep-Pak DNPH-Silica: manufactured by Waters).

After that, the reaction product of DNPH and formaldehyde was extracted with acetonitrile from the DNPH collection tube, and the amount of formaldehyde generated was determined by a calibration curve method using a standard substance of the reaction product of DNPH and formaldehyde with a high-speed liquid chromatograph. , The amount of formaldehyde generated per unit mass of the test piece (μg / g) was calculated.

* Molding machine: FANUC ROBOSHOT α-S100ia (FANUC Co., Ltd.)
* Molding conditions: Cylinder-Temperature (° C) Nozzle-C1-C2-C3
190-190-180-160 ° C
Injection pressure 60 (MPa)
Injection speed 1.0 (m / min)
Mold temperature 80 (° C)

<Evaluation of Mold Deposit (MD)>
Using the polyacetyl resin compositions prepared in Examples and Comparative Examples, a mold deposit test piece (33 mm × 23 mm × 1 mmt) was molded under the following conditions.
[Evaluation method]
After continuous molding of 5000 shots, the surface of the cavity in the mold was visually observed, and the amount of deposits was visually determined according to the following criteria.
⊚: No deposits are confirmed ○: Almost no deposits are confirmed △: Some deposits are confirmed ×: Adhesions are confirmed on the whole XX: A large amount of deposits are confirmed on the whole

* Molding machine: FANUC ROBOSHOT S-2000i 50B (FANUC Co., Ltd.)
* Molding conditions: Cylinder-Temperature (° C) Nozzle-C1-C2-C3
205-215-205-185 ° C
Injection pressure 40 (MPa)
Injection speed 1.5 (m / min)
Mold temperature 80 (° C)

<Evaluation of weather resistance>
A flat molded product (70 mm x 40 mm x 3 mmt) is subjected to a UV fade meter [UV autofade meter FAL-AU-H, B, EM: manufactured by Suga Test Instruments Co., Ltd.] under fade conditions of 83 ° C. After irradiation for 800 hours, it was taken out, and the presence or absence of cracks on the surface of the test piece and the change in hue (ΔE) before and after irradiation were examined by the following method.
-Presence or absence of cracks The surface of the test piece was visually observed to determine the presence or absence of cracks.
・ Hue change (ΔE)
Z-300A type color sensor manufactured by Nippon Denshoku Kogyo Co., Ltd. for the hue (L *, a *, b *) of the molded product.
The change in hue (ΔE) was calculated using the following formula.
ΔE = {(L * ₁ −L * ₀ ) ² + (a * ₁ −a * ₀ ) ² + (b * ₁ −b * ₀ ) ² } ^1/2
L * ₀ , a * ₀ , and b * ₀ indicate the initial hue, and L * ₁ , a * ₁ , and b * ₁ indicate the hue after irradiation.

The smaller the value, the smaller the change in hue.

As described above, it is clear that within the range of the composition of the present invention, it has excellent weather resistance, and the amount of formaldehyde generated and the amount of mold deposit generated are also stably suppressed.

Claims (10)

At least 100 parts by mass of the (A) polyacetyl polymer,
(B) Hindered phenolic antioxidant 0.03 to 0.30 parts by mass,
(C) 0.01 to 0.50 parts by mass of aliphatic carboxylic acid hydrazide,
(D) 0.001 to 0.50 parts by mass of a hydantoin compound having two hydradinocarbonylalkyl groups,
(E) Alkaline earth metal salt of aliphatic carboxylic acid 0.001 to 0.30 parts by mass,
(F) Hinder-doamine compound 0.2 to 1.0 parts by mass,
(G) Containing 0.2 to 1.0 parts by mass of an ultraviolet absorber,
A polyacetyl resin composition in which the total amount of the (C) and (D) is 0.03 to 0.55 parts by mass with respect to 100 parts by mass of the (A) polyacetal polymer. The polyacetyl resin composition according to claim 1, wherein the (F) hindered amine compound is a hindered amine compound in which the nitrogen of a piperidine derivative having a steric hindrance group is tertiary. The polyacetyl resin composition according to claim 1 or 2, wherein the (C) aliphatic carboxylic acid hydrazide is sebacic acid dihydrazide. The polyacetal resin composition according to any one of claims 1 to 3, wherein the alkaline earth metal salt of the (E) aliphatic carboxylic acid is at least one selected from calcium stearate and calcium 12-hydroxystearate. (D) The polyacetyl resin composition according to any one of claims 1 to 4, wherein the hydantoin compound having two hydradinocarbonylalkyl groups is 1,3-bis (hydrazinocarbonoethyl) -5-isopropylhydantoin. Stuff. The (F) hydride amine compound is tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, 1,2,3. 4-Butanetetracarboxylic acid and 1,2,2,6,6-pentamethyl-4-piperidinol and β, β, β', β'-tetramethyl-3,9- (2,4,8,10) -Tetraoxaspiro [5.5] undecane) Selected from condensates with dietaanol, polymers of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidin etanol. The polyacetyl resin composition according to any one of claims 1 to 5, which is one or more of them. The (G) UV absorbers are 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol and N- (2-ethylphenyl)-. The polyacetal resin composition according to any one of claims 1 to 6, which is one or more selected from N'-(2-ethoxyphenyl) oxalic acid diamide. The polyacetyl resin composition according to any one of claims 1 to 7, further containing at least one selected from (H1) fatty acid ester and (H2) polyalkylene glycol. The polyacetyl resin composition according to any one of claims 1 to 8, further comprising (I) 1 to 20 parts by mass of aluminum powder. The method for producing a polyacetyl resin composition according to any one of claims 1 to 9, wherein the (A) polyacetal polymer contains trioxane as a main monomer (a) and at least one carbon-carbon. One or more selected from cyclic ethers and cyclic formates having a bond are designated as comomomer (b), copolymerized using a heteropolyacid as a polymerization catalyst (c), and then an alkali metal element or alkaline earth. A polyacetal copolymer obtained by adding a carbonate, a hydrogen carbonate, a carboxylate or a hydrate (d) thereof of a metal element, melt-kneading the mixture, and deactivating the polymerization catalyst (c). A method for producing a polyacetyl resin composition.