JP4982043B2 - Polyacetal resin composition - Google Patents

Description

  The present invention relates to a polyacetal-based resin composition capable of remarkably suppressing the amount of formaldehyde generated, being excellent in extrusion processability and molding processability, and capable of suppressing blooming, a method for producing the same, and a molded article formed from the resin composition.

  Polyacetal resin has excellent mechanical properties, fatigue resistance, friction and wear resistance, chemical resistance and moldability, so it can be used for automobile parts, electrical / electronic equipment parts, other precision machine parts, building materials / piping members, Widely used in fields such as daily life and cosmetic parts and medical parts. However, with the expansion and diversification of applications, a polyacetal resin having better quality is demanded.

  The properties required for polyacetal resin include that mechanical strength does not decrease during processing such as extrusion or molding, that there is no deposit on the mold (mold deposit), and long-term heating conditions (heat aging). In other words, the mechanical properties are not deteriorated, and molding defects such as silver streaks and voids are not generated. One of the important factors that cause a decrease in strength and physical properties and poor molding is the decomposition of the polymer during heating. In particular, polyacetal resins are essentially easily decomposed under acidic and alkaline conditions in a heated oxidizing atmosphere due to their chemical structure. Therefore, an essential problem of the polyacetal resin is that it has high thermal stability and suppresses generation of formaldehyde from the molding process or the molded product. Formaldehyde is chemically active and becomes formic acid by oxidation, which adversely affects heat resistance. When used in parts of electrical and electronic equipment, metal contact parts corrode or discolor due to adhesion of organic compounds, resulting in poor contact. Produce. Furthermore, formaldehyde itself pollutes the working environment in the parts assembly process and the living environment around the use of the final product.

  In order to stabilize chemically active terminals, homopolymers are esterified by polymerizing the polymer terminals by acetylation, etc., and copolymers are formed by adjacent carbon bonds such as trioxane, cyclic ether and cyclic formal during polymerization. A method is known in which an unstable terminal portion is decomposed and removed to form an inactive stable terminal after copolymerization with a monomer having the monomer. However, cracking also occurs in the main chain part of the polymer during heating, and the prevention cannot be dealt with only by the above treatment. In practice, the addition of stabilizers (antioxidants, other stabilizers, etc.) It is mandatory.

  However, even if a stabilizer is blended, it is difficult to completely suppress the decomposition of the polyacetal resin. In practice, an extruder or a molding is used during the melt processing in the extrusion or molding process for preparing the composition. Under the action of heat and oxygen in the cylinder of the machine, formaldehyde is generated from the end of the main chain decomposition and not fully stabilized, worsening the working environment during extrusion processing. In addition, if molding is performed for a long time, fine powder and tar-like materials adhere to the mold (mold deposit), which is one of the greatest factors that reduce the work efficiency and the surface condition of the molded product. Yes. Furthermore, the mechanical strength is reduced due to polymer decomposition, and the resin is discolored. From such a point, with respect to the polyacetal resin, a great effort has been continued in search of a more effective stabilization formulation.

  As antioxidants added to polyacetal resins, sterically hindered phenolic compounds (hindered phenols) and sterically hindered amine compounds (hindered amines) are known, and other stabilizers include melamine, alkali metal hydroxylation. Such materials, alkaline earth metal hydroxides, organic or inorganic acid salts are known. Usually, the antioxidant is used in combination with other stabilizers. However, even if such an additive is used, it is difficult to suppress formaldehyde generated from the molded product of the polyacetal resin.

US Pat. No. 3,152,101 (Patent Document 1) discloses a composition containing a polyacetal copolymer and a dicarboxylic acid dihydrazide (such as an aliphatic dicarboxylic acid dihydrazide having 3 to 10 carbon atoms). However, when such aliphatic carboxylic acid hydrazide is used, the thermal stability is improved to some extent and the generation of formaldehyde can be suppressed. However, the moldability is low, mold deposits are generated, and the aliphatic Oxidation of acid hydrazide occurs.
U.S. Pat. No. 3,152,101 (columns 1 and 3)

  Accordingly, an object of the present invention is to provide a resin composition capable of improving the thermal stability of a polyacetal resin, the melt stability during extrusion and molding, a method for producing the same, and a molded product.

  Another object of the present invention is to provide a polyacetal resin composition that can remarkably suppress the formation of formaldehyde with a small amount of addition and improve the working environment, a method for producing the same, and a molded article.

  Still another object of the present invention is to suppress the formation of formaldehyde even under harsh conditions, adhesion of decomposition products to the mold, exudation of decomposition products from molded products and thermal deterioration of molded products. The present invention provides a polyacetal resin composition, a method for producing the same, and a molded product that can suppress the above-mentioned, improve the quality of the molded product, and improve the moldability.

  Another object of the present invention is to suppress the generation amount of formaldehyde from the polyacetal resin and the molded product to a very low level, and also have characteristics such as weather resistance (light) resistance, impact resistance, (low) glossiness, and slidability. Is to provide an improved polyacetal resin composition and molded article.

  In order to achieve the above-mentioned problems, the present inventors have conducted a search for a series of carboxylic acid hydrazide compounds with respect to stabilizers for polyacetal resins, and as a result, specific aliphatic carboxylic acid hydrazide compounds are generated from molded articles of polyacetal resins. The inventors have found that formaldehyde can be remarkably suppressed, that it is excellent in molding processability and that bleeding from a molded product can be reduced, and the present invention has been completed.

That is, the polyacetal resin composition of the present invention is composed of a polyacetal resin and an aliphatic carboxylic acid hydrazide represented by the following formula (1).
X— (R—C (═O) —NHNH ₂ ) _n (1)
(Wherein X represents a heteroatom or an n-valent heteroatom-containing group, R represents an alkylene group, and n represents an integer of 1 to 4)
In the formula (1), the heteroatom-containing compound corresponding to the heteroatom-containing group X is a chain or cyclic amine (azacycloalkane, azacycloalkene, azacycloalkadiene, cyclic urea (including cyclic ureido compounds), Cyclic imides), chain or cyclic alcohols (monohydroxyarenes, polyhydroxyarenes, bisphenols (biphenol, bisphenol, etc.)), or chain or cyclic ethers (oxacycloalkanes, oxaspiroalkanes (mono or polyoxaspiro) C _6-20 alkane and the like) and R may be a linear or branched C _1-10 alkylene group (such as a linear or branched C _1-6 alkylene group). The proportion of the aliphatic carboxylic acid hydrazide may be about 0.001 to 20 parts by weight with respect to 100 parts by weight of the polyacetal resin.

  The polyacetal resin composition further includes an antioxidant, a heat stabilizer, a processing stabilizer, a weather resistance (light) stabilizer, an impact resistance improver, a gloss control agent, a slidability improver, a colorant and a filler. It may contain at least one selected from. In the polyacetal resin composition, a pellet of the polyacetal resin and a master batch containing the aliphatic carboxylic acid hydrazide or the aliphatic carboxylic acid hydrazide may coexist. In addition, the resin composition of this invention can also improve heat-resistant stability, even if it does not contain a phosphorus flame retardant substantially.

  The present invention provides a method for producing a polyacetal resin composition in which a polyacetal resin and the aliphatic carboxylic acid hydrazide are melt-mixed using an extruder, and (a) at least the aliphatic carboxylic acid hydrazide is fed to the side of the extruder. A method of producing a polyacetal resin composition by a method of mixing by feeding from the mouth and / or a method of (b) setting an average residence time in the extruder to 300 seconds or less is also included.

  The present invention further includes a molded article formed from the polyacetal resin composition. The molded article may be an automobile part, an electric / electronic part (electrical and / or electronic part), a building material / pipe part (building material and / or a pipe part), a life / cosmetic part (life and / or cosmetic part), or a medical product. It may be a part.

  In the present invention, since a specific aliphatic carboxylic acid hydrazide is added to the polyacetal resin, the thermal stability of the polyacetal resin and the melt stability during extrusion and molding can be improved. Moreover, the formation of formaldehyde can be remarkably suppressed by adding a small amount of the carboxylic acid hydrazide, and the surrounding environment (working environment, use environment, etc.) can be greatly improved. Furthermore, even under harsh conditions, the amount of formaldehyde generated can be suppressed to an extremely low level, the decomposition products adhere to the mold (mold deposit), the decomposition products exude from the molded products and the heat of the molded products. It is possible to suppress deterioration, improve the quality of the molded product, and improve moldability. In addition, when other additives (weather resistance (light) stabilizer, impact resistance improver, gloss control agent, slidability improver, colorant, filler, etc.) are added, polyacetal resin and formaldehyde from molded products It is also possible to provide a polyacetal resin composition and a molded article having improved properties such as weather resistance (light), impact resistance, (low) gloss, and slidability while suppressing the generation amount of it can.

  The resin composition of the present invention is composed of a polyacetal resin and a specific carboxylic acid hydrazide.

(Polyacetal resin)
The polyacetal resin is a polymer compound having an oxymethylene group (—OCH ₂ —) as a main structural unit, such as a polyacetal homopolymer or polyoxymethylene (for example, trade name “Delrin”, Asahi Kasei Kogyo Co., Ltd., USA) And a polyacetal copolymer containing an oxymethylene unit and a comonomer unit (for example, a product name “Duracon” manufactured by Polyplastics Co., Ltd.). In the copolymer, the comonomer unit includes an oxyalkylene unit (for example, an oxyethylene group (—OCH ₂ CH ₂ —), an oxypropylene group, an oxytetramethylene group having about 2 to 6 carbon atoms (preferably about 2 to 4 carbon atoms). Group). The content of the comonomer unit is a small amount, for example, 0.01 to 20 mol%, preferably 0.03 to 15 mol% (for example, 0.05 to the entire polyacetal resin (monomer unit constituting the polyacetal resin)). To 10 mol%), more preferably from about 0.1 to 10 mol%.

  The polyacetal copolymer may be a copolymer composed of two components, a terpolymer composed of three components, or the like. The polyacetal copolymer is a random copolymer, a block copolymer (for example, a copolymer described in Japanese Patent Publication No. 2-24307, manufactured by Asahi Kasei Kogyo Co., Ltd., trade names “TENAC LA”, “TENAC LM”, etc.), a graft copolymer, and the like. May be. Moreover, the polyacetal resin may have a branched structure as well as a linear structure, and may have a crosslinked structure. Furthermore, the terminal of the polyacetal resin may be stabilized by, for example, esterification with a carboxylic acid such as acetic acid or propionic acid or an anhydride thereof, urethanization with an isocyanate compound, or etherification. The polymerization degree, branching degree, and crosslinking degree of the polyacetal are not particularly limited as long as it can be melt-molded. The molecular weight of the polyacetal resin is not particularly limited, and is, for example, a weight average molecular weight of 5,000 to 500,000, preferably about 10,000 to 400,000.

  Examples of the polyacetal resin include aldehydes such as formaldehyde, paraformaldehyde, and acetaldehyde, trioxane, ethylene oxide, propylene oxide, butylene oxide, styrene oxide, cyclohexane oxide, cyclohexene oxide, 1,3-dioxolane, 1,3-dioxane, It can be produced by polymerizing cyclic ethers such as diethylene glycol formal and 1,4-butanediol formal, and cyclic formal. Further, as a copolymerization component, alkyl or aryl glycidyl ether (for example, methyl glycidyl ether, ethyl glycidyl ether, phenyl glycidyl ether, naphthyl glycidyl ether, etc.), alkylene or polyoxyalkylene glycol diglycidyl ether (for example, ethylene glycol diglycidyl ether) Ether, triethylene glycol diglycidyl ether, butanediol diglycidyl ether, etc.), alkyl or aryl glycidyl alcohol, cyclic esters (eg, β-propiolactone, etc.), vinyl compounds (eg, styrene, vinyl ether, etc.), etc. You can also

(Carboxylic acid hydrazide)
The feature of the present invention is that by adding a hydrazide of a heteroatom-containing aliphatic carboxylic acid represented by the following formula (1), the processing stability of the polyacetal resin is greatly improved, and generation of formaldehyde is remarkably suppressed. It is in.
X— (R—C (═O) —NHNH ₂ ) _n (1)
(Wherein X represents a heteroatom or an n-valent heteroatom-containing group, R represents an alkylene group, and n represents an integer of 1 to 4)
Examples of the hetero atom represented by X include a nitrogen atom, an oxygen atom, and a sulfur atom. Moreover, the hetero atom containing group represented by X should just contain the at least 1 type of hetero atom selected from the nitrogen atom, the oxygen atom, and the sulfur atom (especially nitrogen atom and oxygen atom), and an amino group (- In addition to NH ₂ ), imino group (> NH), hydroxyl group, mercapto group and the like, a chain-like or cyclic heteroatom-containing group can be mentioned. When the group X is a nitrogen atom-containing group, the group X usually may contain a nitrogen atom (—N <) and / or an imino group (—NH—), and these nitrogen atom and imino group May be derived from an iminocarbonyl bond (> N—C (═O) —, —NH—C (═O) —) such as an amide bond, an imide bond, a ureido bond, or a urethane bond.

  Examples of the heteroatom-containing compound corresponding to the heteroatom-containing group X include a nitrogen-containing compound such as a chain or cyclic amine; an oxygen-containing compound such as a chain or cyclic alcohol, a chain or cyclic ether; and the oxygen-containing compound. And sulfur-containing compounds corresponding to. The cyclic heteroatom compound may be a heterocyclic compound having a heteroatom as an atom constituting the ring, and a heteroatom-containing group (nitrogen atom, imino group, amino group, oxygen atom, hydroxyl group, ether group, etc. ) May be a cyclic compound having a structure in which a ring (hydrocarbon ring, heterocycle (usually hydrocarbon ring), etc.) is connected.

  Examples of the chain amine include aliphatic amines such as amino linear or branched alkanes; amino linear or branched alkanols; (poly) alkylene polyamines such as alkylene diamine and dialkylene triamine; aryl linear or Examples include branched alkylamines; di (amino linear or branched alkyl) arenes. Examples of the cyclic amine include alicyclic amines (mono or polyamino- (poly) cycloalkane, mono or polyamino- (poly) cycloalkene, etc.), aromatic amines (mono or polyamino-arene, etc.), etc. Cycloalkanes (pyrrolidine, piperidine, pipecoline, piperazine, morpholine, etc.), azacycloalkenes or azacycloalkadienes (pyrroline, imidazoline, imidazolone, imidazole, etc.), cyclic ureas (alkylene urea, polycyclic cyclic urea, hydantoin, etc.) Ureido, etc.), and heterocyclic amines such as cyclic imides.

  Examples of chain alcohols include aliphatic alcohols such as mono- or polyhydroxyalkanes and polyalkylene glycols. Cyclic alcohols include alicyclic alcohols (mono or polyhydroxycycloalkane, mono or polyhydroxycycloalkene, mono or polyhydroxycycloalkadiene, hydrogenated bisphenols, etc.), aromatic alcohols (monohydroxyarene, poly Hydroxyarenes, bisphenols (biphenol, bisphenol, etc.)) and the like. The chain or cyclic alcohol may be a monohydric or polyhydric alcohol. The chain or cyclic alcohol may have a substituent (a substituent described later, such as a hydrazinocarbonyl group).

  Examples of the chain ether include alkyl-aryl ether and alkyl-aralkyl ether. Examples of cyclic ethers include alicyclic ethers, aromatic ethers, and oxygen-containing rings such as oxa (poly) cycloalkanes, oxa (poly) cycloalkenes, and oxaspiroalkanes.

  When X is a heteroatom-containing group, the group X may be bonded to the group R on a heteroatom (nitrogen atom, oxygen atom, etc.), or may be directly bonded on a carbon atom. When group X is a nitrogen atom-containing group, the bonding site to group R may be on the nitrogen atom, and when group X is an oxygen atom-containing group, the bonding site to group R may be on a carbon atom. Good.

Examples of the alkylene group represented by R in the formula (1) include linear or branched C _1-10 alkylene groups such as methylene, ethylene, propylene, trimethylene and t-butylene groups (preferably C _1-6 alkylene). Group).

  The carboxylic acid hydrazide may be a hydrazide of a monovalent carboxylic acid, or a hydrazide of a polyvalent carboxylic acid in which n is a plural number (such as an integer of 2 to 4) in the formula (1). In the formula (1), n is preferably an integer of 1 to 3, and more preferably 1 or 2.

The hydrazide of the heteroatom-containing aliphatic carboxylic acid has a substituent such as an oxo group (═O), a hydroxyl group, an amino group, an N-substituted amino group (N-mono such as methylamino, dimethylamino group or the like, N, N-diC _1-4 alkylamino group, etc.), alkyl group (straight chain or branched C _1-16 alkyl group such as methyl, ethyl, isopropyl group; hydroxy C _1-6 alkyl group such as methylol, ethylol group, etc. Amino C _1-6 alkyl group such as aminoethyl group), aryl group (C _6-10 aryl group _optionally having a substituent such as phenyl, hydroxyphenyl group, etc.), aralkyl group (C _6-10 aryl-C _1-4 alkyl group such as benzyl group), hydrazinocarbonyl group and the like may be included. The aliphatic carboxylic acid hydrazide may have one or a combination of two or more of these substituents. The substituent may be substituted on the group R, but usually may be substituted on the heteroatom-containing group X. The substitution position of the substituent is not particularly limited, and may be on a carbon atom or a nitrogen atom. Of the above substituents, the oxo group is usually substituted on a carbon atom and may form a carbonyl group (—C (═O) —) with the carbon atom.

The carboxylic acid hydrazide (1) is not particularly limited, and can be obtained, for example, by reaction of the corresponding carboxylic acid ester (1a) with hydrazine hydrate (or hydrazine H ₂ NNH ₂ ).
X- (R-COOR ¹ ) _n (1a)
(In the formula, R ¹ represents an alkyl group such as a methyl group or an ethyl group. X, R and n are the same as described above.)
In addition, in the carboxylic acid hydrazide in which the group X is bonded to the group R on the nitrogen atom, the starting carboxylic acid ester (1a) includes, for example, an amine (the chain or cyclic amine) corresponding to the group X and the group R Α, β-unsaturated carboxylic acid esters (α, β-C _1-10 unsaturated carboxylic acid esters (α, β-C _3-10 such as methyl (meth) acrylate, ethyl (meth) acrylate)) The unsaturated carboxylic acid ester) and the like, and the α, β-unsaturated carboxylic acid ester is added to the amino group or imino group of the amine. It can also be obtained by addition reaction of an amine derivative corresponding to the group X and (meth) acrylonitrile, and hydrolysis and esterification of the adduct. Details of such reaction include, for example, JP-A-59-67256, JP-A-60-178851, US Pat. No. 4,465,830, US Pat. No. 4,544,733, etc. Can be referred to. In addition, in the carboxylic acid hydrazide in which the group X is bonded to the group R on the oxygen atom, the starting carboxylic acid ester (1a) is a linear or cyclic alcohol corresponding to the group X and a halocarboxylic acid corresponding to the group R ( And monohalogenated C _1-10 alkane-carboxylic acid such as monochloroacetic acid). For details of this reaction, reference can be made to, for example, JP-A-58-131953 and JP-A-61-183316.

The carboxylic acid hydrazide (1) in which X is a nitrogen atom and n is 3 is, for example, concentrated ammonia water and an α, β-unsaturated carboxylic acid ester ((meth)) having a molar ratio of 3 times or more. An α, β-unsaturated carboxylic acid ester 3-mole adduct of ammonia by reacting with an acrylic ester, etc., and further reacting with hydrazine hydrate 3 times or more in methanol solvent. Obtainable. The details of this reaction can be referred to, for example, JP-A-3-193533. Carboxylic acid hydrazide (1) in which X is an oxygen atom and n is 2 is, for example, R ¹ OOC-R—O—R—COOR ¹ (wherein R and R ¹ are the same as above) (for example, Diglycolic acid diester and the like) and hydrazide hydrate.

Among such hydrazides of heteroatom-containing aliphatic carboxylic acids, carboxylic acid hydrazides in which X is a nitrogen atom include N-mono to tris (hydrazinocarbonylalkyl) amine [for example, mono to tris (hydrazinocarbonyl straight chain). Chain C _1-6 alkyl) amine and mono to tris (hydrazinocarbonyl branched C _1-6 alkyl) amine (for example, N, N, N-tris (hydrazinocarbonylethyl) amine, etc.)] and the like. included.

Specific examples of the carboxylic acid hydrazide in which the heteroatom-containing compound corresponding to the group X is an aliphatic amine include N-mono or bis (hydrazinocarbonyl linear C _1-6 alkyl) aminoalkane and N- Mono or bis (hydrazinocarbonyl branched C _1-6 alkyl) aminoalkane [eg N-mono or bis (hydrazinocarbonyl linear C _1-6 alkyl) amino C _1-10 alkane and N-mono or Bis (hydrazinocarbonyl branched C _1-6 alkyl) amino C _1-10 alkane (eg, N-mono or N, N-bis (hydrazinocarbonylethyl) aminobutane, etc.)], N-mono or bis ( hydrazinocarbonyl alkyl) amino alkanol [e.g., N- mono- or bis (hydrazinocarbonyl linear C _1-6 alkyl) amino C _1-10 alk Lumpur and N- mono- or bis (hydrazinocarbonyl branched C _1-6 alkyl) amino C _1-10 alkanols (e.g., N- mono- or N, N- bis (hydrazinocarbonylmethyl ethyl) such as amino ethanol) etc. ], N-mono or poly (hydrazinocarbonylalkyl) (poly) alkylenepolyamine [mono or bis (hydrazinocarbonyl C _1-6 alkylamino) C _1-6 alkane (wherein the C _1-6 alkyl group is straight May be chain or branched), for example, N-mono or N, N-bis (hydrazinocarbonyl C _1-6 alkyl) amino C _1-6 alkane (eg, 1,2-bis (N— Mono- or N, N-bis (2-hydrazinocarbonylethyl) amino) ethane, 1,2-bis (N-mono or N, N-bis (2-hydrazinocarbonylmethyl) amino) ethane, 4- bis (N- mono- or N, N-bis (2-hydrazinocarbonyl-ethyl) amino) butane, etc.); mono- to pentakis (hydrazinocarbonyl C _1-6 alkyl) di-C _1-6 alkylene triamines (Note , C _1-6 alkyl group may be linear or branched), for example, mono to pentakis (hydrazinocarbonyl C ₁ ) such as N, N′-bis (2-hydrazinocarbonylethyl) diethylenetriamine. _-6 alkyl) di-C _1-6 alkylene triamines such], N-mono- or bis (hydrazinocarbonyl alkyl) amino - aryl - alkane [e.g., 1-[N-mono- or N, N-bis (hydrazinocarbonylmethyl ethyl ) amino] -4-phenylbutane such as N- mono- or N, N- bis (hydrazinocarbonylmethyl C _1-6 alkyl) amino -C _6-10 aryl C _1-6 alkanes (Note, C _1-6 alkyl group, straight or branched chain and there may be) such], N-mono- or poly (hydrazinocarbonyl alkyl) aralkylene diamines [bis (hydrazino Carbonyl linear or branched C _1-6 alkylamino C _1-6 alkyl) C _6-10 arenes such as N, N′-bis (2-hydrazinocarbonylethyl) -m-xylylenediamine, N, N′-bis (1-methyl-2-hydrazinocarbonylethyl) -m-xylylenediamine, 1,4-bis (2′-bis (N-mono or N, N-bis (hydrazinocarbonylethyl) amino) Bis (N-mono or N, N-bis (hydrazinocarbonyl C _1-6 alkyl) amino) C _1-6 alkyl) C _6-10 arene (bis (mono or bis (hydrazinocarbonyl C) _1-6 A Kiruamino) a C _1-6 alkyl) C _6-10 arene), etc.] Other, JP 59-67256, JP-Sho 60-178851 JP and carboxylic acid hydrazide of JP-A 3-193753 JP Etc.

Specific examples of the carboxylic acid hydrazide in which the heteroatom-containing compound is an alicyclic amine include mono- or poly (hydrazinocarbonyl C _1-6 alkylamino) C _5-8 cycloalkane such as N-mono or N, N-mono or N, N-bis (hydrazino) such as N-bis (hydrazinocarbonylethyl) aminocyclohexane, 1,4-bis (N-mono or N, N-bis (hydrazinocarbonylethyl) amino) cyclohexane Carbonyl C _1-6 alkyl) amino C _5-8 cycloalkane and the corresponding mono- or poly (hydrazinocarbonyl C _1-6 alkylamino) C _5-8 cycloalkene (eg N-mono or N, N-bis ( such hydrazinocarbonyl C _1-6 alkyl) amino C _5-8 cycloalkene and the like. in these carboxylic acid hydrazide, Dora Gino carbonyl C _1-6 alkyl group may be a hydrazinocarbonyl straight or branched chain C _1-6 alkyl group.

Specific examples of carboxylic acid hydrazides in which the heteroatom-containing compound is an aromatic amine include mono- or poly (hydrazinocarbonyl linear or branched C _1-6 alkylamino) arenes such as N-mono (2-hydra). Mono (N-mono or N, N-bis (hydrazinocarbonylalkyl) amino) C _6-14 arene such as dinocarbonylethyl) aminobenzene; N, N-bis (2-hydrazinocarbonylethyl) aminobenzene, 1 , 2-, 1,3- or 1,4-bis (N-mono or N, N-bis (2-hydrazinocarbonylethyl) amino) benzene or the like bis (N-mono or N, N-bis (hydra) Gino carbonyl alkyl) amino) C _6-14 arene; N- mono (2-hydrazinocarbonyl-ethyl) amino, bis (N- (Hidorajinokarubo Ruarukiru) amino C _6-10 aryl) straight or branched chain C _1-4 alkanes [bis (N-(2-hydrazinocarbonyl-ethyl) aminophenyl) methane, bis (N-(1-methyl-2-hydrazone Mono or bis (N-mono (hydrazinocarbonylalkyl) amino) bis C _6-10 aryl; N, N-bis (2-hydrazinocarbonylethyl) aminobiphenyl, etc. Bis (N, N-bis (hydrazinocarbonylalkyl) amino C _6-10 aryl) linear or branched C _1-4 alkane [bis (N, N-bis (2-hydrazinocarbonylethyl) aminophenyl) Methane, bis (N, N-bis (1-methyl-2-hydrazinocarbonylethyl) aminophenyl) methane and the like] or the like or bis (N, N- Scan (hydrazinocarbonyl alkyl) amino) other bis C _6-10 aryl, a carboxylic acid hydrazide as described in U.S. Patent No. 4,544,733 and the like.

Specific examples of carboxylic acid hydrazides in which the heteroatom-containing compound is an azacycloalkane include mono- or polyaza C _5-8 cycloalkanes having a hydrazinocarbonyl linear or branched C _1-6 alkyl group, such as 1- A piperidine ring such as (2-hydrazinocarbonylethyl) piperidine, 1- (2-hydrazinocarbonylethyl) pipecholine and the like may have a substituent (C _1-4 alkyl group, etc.) exemplified above. Hydrazinocarbonylalkyl) piperidine; 1-mono or 1,4-bis (2-hydrazinocarbonylethyl) piperazine, 1-mono or 1,4-bis (1-methyl-2-hydrazinocarbonylethyl) piperazine, 1 -Piperazine rings such as mono or 1,4-bis (2-hydrazinocarbonylethyl) -2,5-dimethylpiperazine Wherein such exemplary substituents (such as C _1-4 alkyl group) may have a 1-mono or 1,4-bis (hydrazinocarbonyl alkyl) piperazine. The carboxylic acid hydrazide also includes 4- (hydrazinocarbonyl linear or branched C _1-6 alkyl) morpholine such as 4- (hydrazinocarbonylethyl) morpholine.

Examples of the carboxylic acid hydrazide in which the heteroatom-containing compound is an azacycloalkene or an azacycloalkadiene include the above-described substituents (C _1-14 alkyl group, C _6-10 aryl group, oxo group, etc.) on the azacycloalkene ring ) Hydrazinocarbonyl linear or branched C _1-6 alkylaza C _5-8 cycloalkene [monoazacycloalkene such as N- (2-hydrazinocarbonylethyl) pyrroline; N-hydra Dinocarbonylalkylimidazolines (1- (2-hydrazinocarbonylethyl) -2-imidazoline, 1- (2-hydrazinocarbonylethyl) -3-imidazoline, 1-mono or 1,3-bis (2-hydrazino Carbonylethyl) -4-imidazoline, etc.), N-hydrazinocarbonylalkylimidazolones (1-mono or 1,3-bis (2-hydrazinocarbonylethyl) -2 (3H) -imidazolone, 1- (2-hydrazinocarbonylethyl) -4 (5H) -imidazolone, 1- (2-hydrazinocarbonylethyl)- 5 (4H) -imidazolone etc.) and the like, and the azacycloalkadiene ring may have the above exemplified substituents (C _1-14 alkyl group, C _6-10 aryl group etc.) Good hydrazinocarbonyl linear or branched C _1-6 alkylaza C _5-8 cycloalkene [mono (azacycloalkadiene) such as 1- (2-hydrazinocarbonylethyl) pyrrole; N-hydrazinocarbonylalkylimidazoles ( 1- (2-hydrazinocarbonylethyl) imidazole, 1- (2-hydrazinocarbonylethyl) -2-methylimidazole, 1 (2-hydrazinocarbonylethyl) -2-undecylimidazole, 1- (2-hydrazinocarbonylethyl) -2-phenylimidazole, 1- (2-hydrazinocarbonylethyl) -2-ethyl-4-methylimidazole 1- (hydrazinocarbonylalkyl) imidazoles such as 1- (2-hydrazinocarbonylethyl) -2-phenyl-4-methylimidazole; 2- (hydrazinocarbonylalkyl) such as 2- (hydrazinoethyl) imidazole Diazacycloalkadiene such as imidazoles) and the like.

Carboxylic acid hydrazides in which the heteroatom-containing compound is a cyclic urea include, for example, N-mono or N, N′-bis (hydrazinocarbonylalkyl) alkyleneurea [1- (2-hydrazinocarbonylethyl) ethyleneurea, 1 , 3-bis (2-hydrazinocarbonylethyl) ethylene urea, 1,3-bis (1-methyl-2-hydrazinocarbonylethyl) ethylene urea, 1,3-bis (2-hydrazinocarbonylethyl) propylene urea N-mono or N, N′-bis (hydrazinocarbonyl linear or branched C _1-6 alkyl) C _1-8 alkylene-urea etc.], N-mono or poly (hydrazinocarbonylalkyl) poly Cyclic cyclic urea [1-mono to 1,3,4,6-tetra (2-hydrazinocarbonylethyl) acetylene urea, 1-mono to 1,3,3 4,6-tetra (1-methyl-2-hydrazinocarbonylethyl) acetylene urea, 3-mono or 3,4-bis (1-methyl-2-hydrazinocarbonylethyl) -1,6-dimethylacetylene urea, etc. In addition to N-mono to tetra (hydrazinocarbonyl linear or branched C _1-6 alkyl) acetylene urea which may have a substituent such as a C _1-4 alkyl group in the acetylene urea, Also included are cyclic ureidos having a hydrazinocarbonylalkyl group.

Examples of the cyclic ureido having the hydrazinocarbonylalkyl group (such as a hydrazinocarbonyl linear or branched C _1-6 alkyl group) include N-mono or N, N′-bis (2-hydrazinocarbonylethyl) barbitur. Ureides of dicarboxylic acids such as acids; ureides of β-aldehyde acids such as N-mono or N, N′-bis (2-hydrazinocarbonylethyl) uracil; N-mono to tetrakis (2-hydrazinocarbonylethyl) uric acid In addition to cyclic diureides such as: ureido of α-oxyacids such as hydantoin having a hydrazinocarbonylalkyl group.

Examples of the hydantoin having this hydrazinocarbonylalkyl group include 1 or 3-mono (hydrazinocarbonylalkyl) hydantoin, 1,3-bis (hydrazinocarbonylalkyl) hydantoin, and the like. It may have two substituents (a linear or branched C _1-6 alkyl group such as a methyl group, a C _6-10 aryl group such as a phenyl group, etc.). A ring may be formed together with the carbon atom at the 5-position. Examples of such a compound include hydrazino such as 1- or 3-mono (hydrazinocarbonylalkyl) hydantoin [1- (hydrazinocarbonylethyl) hydantoin, 3- (hydrazinocarbonylethyl) -5,5-dimethylhydantoin. Carbonyl straight-chain or branched C _1-6 alkylhydantoin and the like], 1,3-bis (hydrazinocarbonyl straight-chain or branched C _1-6 alkyl) hydantoin [1,3-bis (2-hydrazinocarbonyl) Ethyl) -5-methylhydantoin, 1,3-bis (2-hydrazinocarbonylethyl) -5-isopropylhydantoin, 1,3-bis (2-hydrazinocarbonylethyl) -5,5-dimethylhydantoin, 1, 3-bis (1-methyl-2-hydrazinocarbonylethyl) -5,5-dimethylhydanto Emissions, such as the 5-mono- or 5,5-di - hydantoin (di- straight or branched chain C _1-4 alkyl - such as hydantoin); 1,3-bis (2-hydrazinocarbonyl-ethyl) -5-phenyl hydantoin 5- mono- or 5,5-di-C _6-10 aryl, such as - hydantoin; 1,3-bis (2-hydrazinocarbonyl-ethyl) -5,5-like pentamethylene spirohydantoin 5,5-C _{3- 8} alkylene spirohydantoin, etc.], and hydantoin carboxylic acid hydrazide described in US Pat. No. 4,465,830. Of these, compounds having 1 or 2 substituents at the 5-position of the hydantoin ring are preferred.

As the carboxylic acid hydrazide in which the heteroatom-containing compound corresponding to the group X is a cyclic imide, the cyclic imide having a hydrazinocarbonylalkyl group is N- (2-hydrazinocarbonylethyl) succinimide, N- (2-hydra). In addition to N- (hydrazinocarbonyl linear or branched C _1-6 alkyl) C _4-8 cyclic imide such as _{dinocarbonylethyl} ) glutarimide, C ₈ having a benzene ring condensed to this C _4-8 cyclic imide. _-12 condensed cyclic imide [N- (2-hydrazinocarbonylethyl) phthalimide, N- (1-methyl-2-hydrazinocarbonylethyl) phthalimide, N- (hydrazinocarbonylethyl) -4-hydrazinocarbonylphthalimide, Benzene such as N-mono or N, N′-bis (hydrazinocarbonylethyl) pyromellitimide The substituent (C _1-4 alkyl group such as methyl group, a carboxyl group, hydrazinocarbonyl group, etc.) may have N- (hydrazinocarbonyl straight or branched chain C _1-6 alkyl) C _8-12 aromatic polycarboxylic acid imide, etc.].

On the other hand, carboxylic acid hydrazides in which X is an oxygen atom include bis (hydrazinocarbonylmethyl) ether, bis (2-hydrazinocarbonylethyl) ether, bis (1-methyl-2-hydrazinocarbonylethyl) ether, and the like. Bis (hydrazino linear or branched C _1-6 alkyl) ether is included.

Examples of the carboxylic acid hydrazide in which the heteroatom-containing compound corresponding to the group X is an aliphatic alcohol include mono- or poly (hydrazinocarbonylalkyloxy) alkane [1,2-bis (2-hydrazinocarbonylethyloxy) ethane. 1,3-bis (2-hydrazinocarbonylethyloxy) propane, 1,4-bis (2-hydrazinocarbonylethyloxy) butane, 1,3-bis (2-hydrazinocarbonylethyloxy) -2, Mono- or tetrakis (hydrazinocarbonylalkoxy) alkanes (hydrazino) such as 2-dimethylpropane, 1,2,3-tris (2-hydrazinocarbonylethyloxy) propane, tetrakis (2-hydrazinocarbonylethyloxymethyl) methane Carbonyl straight chain C _1-6 alkoxy straight chain or minute Branched chain C _1-6 alkane, hydrazinocarbonyl branched chain C _1-6 alkoxy straight chain or branched chain C _1-6 alkane, etc.)], polyalkylene glycol-bis (hydrazinocarbonylalkyl) ether [diethylene glycol - bis (2-hydrazinocarbonyl-ethyl) ether, polyethylene glycol - poly C _2-4 alkylene glycol such as bis (2-hydrazinocarbonyl-ethyl) ether - bis etc. (hydrazinocarbonyl C _1-6 alkyl) ether], etc. Is mentioned.

Specific examples of the carboxylic acid hydrazide in which the heteroatom-containing compound is an alicyclic alcohol include, for example, mono or poly (hydrazinocarbonylalkyloxy) cycloalkane [mono or di (hydrazinocarbonylethoxy) cyclohexane, hydrazinocarbonylethoxy. (Poly) C _5-8 cycloalkene such as decalin], mono or poly (hydrazinocarbonylalkyloxy) cycloalkene [(poly) C _5-8 cycloalkene such as mono or di (hydrazinocarbonylethoxy) cyclohexene] , mono- or poly (hydrazinocarbonyl alkyloxy) cycloalkadiene [mono- or di (hydrazinocarbonyl ethoxy) cyclohexadiene such as (poly) C _5-8 cycloalkadiene etc.], hydrazinocarbonyl hydrogenated bisphenols Ruki ether [4,4 '- (2-hydrazinocarbonyl ethoxy) hydrogenated biphenyl, bis (4- (2-hydrazinocarbonyl ethoxy) cyclohexyl) methane], and others.

The carboxylic acid hydrazide in which the heteroatom-containing compound corresponding to the group X is an aromatic alcohol includes mono (hydrazinocarbonyl linear or branched C _1-6 alkoxy) arene, poly (hydrazinocarbonyl linear or branched) And chain C _1-6 alkoxy) arene. The arene ring constituting this carboxylic acid hydrazide may have one or more substituents (C _1-4 alkyl group such as methyl group, carboxyl group, hydrazinocarbonyl group, etc.). Such compounds include, for example, monohydrazinocarbonylalkoxy C _6-10 arene [(hydrazinocarbonylmethyloxy) benzene, (2-hydrazinocarbonylethyloxy) benzene, 1,2-, 1,3- or 1,4-bis (hydrazinocarbonylmethyloxy) benzene, 1,2-, 1,3- or 1,4-bis (2-hydrazinocarbonylethyloxy) benzene, 1,3,5-tris (2- Hydrazinocarbonylethyloxy) benzene, 2-, 3- or 4- (hydrazinocarbonylmethyloxy) benzoic acid hydrazide, 2-, 3- or 4- (2-hydrazinocarbonylethyloxy) benzoic acid hydrazide, 2- , 3, or 4- (1-methyl-2-hydrazinocarbonylethyloxy) benzoic acid hydrazide, (hydrazinocar Nylmethyloxy) naphthalene, 3- (hydrazinocarbonylethyloxy) -2-naphthalenecarboxylic acid hydrazide, 6- (hydrazinocarbonylethyloxy) -2-naphthalenecarboxylic acid hydrazide, etc.], mono or bis (hydrazinocarbonylalkoxy) ) Bis C _6-10 aryl [4,4′-bis (hydrazinocarbonylmethyloxy) biphenyl, 4,4-bis (2-hydrazinocarbonylethyloxy) biphenyl, 4,4′-bis (1-methyl-) 2-hydrazinocarbonylethyloxy) biphenyl, biphenyls such as 4 ′-(2-hydrazinocarbonylethyloxy) -4-biphenylcarboxylic acid hydrazide; 4,4′-bis (hydrazinocarbonylmethyloxy) diphenylmethane, bis (4- (2-hydrazinocarbonylethyl) Ruoxy) phenyl) methane, 2,2-bis (4- (hydrazinocarbonylmethyloxy) phenyl) propane, 2,2-bis (4- (2-hydrazinocarbonylethyloxy) phenyl) propane, 2,2- Bis-C _6-10 aryl linear or branched C _1-4 alkanes such as bis (4- (1-methyl-2-hydrazinocarbonylethyloxy) phenyl) propane; bis (4- (2-hydrazino Carbonylethyloxy) phenyl) ether, bis (4- (2-hydrazinocarbonylethyloxy) phenyl) sulfide, bis (4- (2-hydrazinocarbonylethyloxy) phenyl) sulfone, bis (4- (2-hydra) In addition to Dinocarbonylethyloxy) phenyl) ketone etc.], JP-A-58-131953, JP-A-59-24 Such as carboxylic acid hydrazides described in, 14 and JP 61-183316 JP include. For methods for preparing these carboxylic acid hydrazides, reference can be made to, for example, JP-A-58-131953, JP-A-59-24714, and JP-A-61-183316.

Specific examples of the carboxylic acid hydrazide in which the heteroatom-containing compound is an alicyclic ether include, for example, C _1-10 alkoxy-hydrazinocarbonyl such as 1-ethoxy-4- (2′-hydrazinocarbonylethyl) cyclohexane. Linear or branched C _1-6 alkyl-C _5-8 cycloalkane; cyclohexyl-4- (2′-hydrazinocarbonylethyl) cyclohexyl ether, bis (4- (2′-hydrazinocarbonylethyl) cyclohexyl) Bis ((mono or bishydrazinocarbonyl C _1-6 alkyl) C _5-8 cycloalkyl) ether such as ether (bis (hydrazinocarbonyl linear or branched C _1-6 alkyl C _5-8 cycloalkyl)) Ether, etc.).

Specific examples of the carboxylic acid hydrazide in which the heteroatom-containing compound is an aromatic ether include, for example, C _1-10 alkoxy-hydrazinocarbonyl straight chain such as 1-ethoxy-4- (2′-hydrazinocarbonylethyl) benzene. Chain or branched C _1-6 alkyl-C _6-10 arene; 4- (2′-hydrazinocarbonylethyl) phenyl-phenyl ether, bis (4- (2′-hydrazinocarbonylethyl) phenyl) ether, etc. Bis ((mono or bishydrazinocarbonyl C _1-6 alkyl) C _6-10 aryl) ether (such as bis (hydrazinocarbonyl linear or branched C _1-6 alkyl C _6-10 aryl) ether), etc. Is mentioned.

Examples of the carboxylic acid hydrazide in which the heteroatom-containing compound corresponding to the group X is an oxygen-containing ring include, for example, hydrazinocarbonylalkyl (eg, hydrazinocarbonyl linear or branched C _1-6 alkyl) oxacycloalkane. [Hydrazinocarbonylethyltetrahydrofuran, 5-methylol-5-ethyl-2- (2-hydrazinocarbonylethyl) -1,3-dioxane, 5-methylol-5-ethyl-2- (hydrazinocarbonylalkyl) -1 , 3-dioxane (5-methylol-5-ethyl-2- (1,1-dimethyl-2-hydrazinocarbonylethyl) -1,3-dioxane etc.) and the like, the substituents exemplified above ( 5-8 membered mono- or polyoxa which may have an alkyl group, a hydroxyalkyl group, etc. Cycloalkanes (such as mono or dioxacycloalkanes)], hydrazinocarbonylalkyl (eg, hydrazinocarbonyl linear or branched C _1-6 alkyl) oxaspiroalkanes [eg, 3,9-bis (hydrazino) Carbonylalkyl) -2,4,8,10-tetraoxaspiro [5.5] undecane (eg, 3,9-bis (hydrazinocarbonylmethyl) -2,4,8,10-tetraoxaspiro [5. 5] Undecane, 3,9-bis (2-hydrazinocarbonylethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane, 3,9-bis (1,1-dimethyl-1- hydrazinocarbonyl methyl) -2,4,8,10-spiro [5.5] undecane, etc.) mono- or poly-oxa spiro C _6-20 aralkyl such as Emissions (such as mono- to tetra oxa spiro C _8-16 alkane), etc.], oxa cycloalkenes having hydrazinocarbonyl alkyl group (such as a hydrazinocarbonyl straight or branched chain C _1-6 alkyl group) or oxa cycloalkadienes (5-8 membered mono- or dioxacycloalkene or cycloalkadiene such as hydrazinocarbonylethylfuran, hydrazinocarbonylethylpyran, hydrazinocarbonylethyl-2H, 4H-1,3-dioxin; hydrazinocarbonylethyliso Benzofuran, hydrazinocarbonylethyl chromene, etc.).

  These hydrazides of the heteroatom-containing aliphatic carboxylic acid can be used alone or in combination of two or more.

Among the hydrazides of the heteroatom-containing aliphatic carboxylic acid, a heteroatom-containing compound having a hydrazinocarbonyl linear or branched C _1-4 alkyl group (for example, a cyclic amine such as a cyclic ureido compound, an oxaspiroalkane, etc. Cyclic ethers and the like) are preferred. Examples of the aliphatic carboxylic acid hydrazide include hydrazinocarbonylalkylhydantoins [1,3-bis (2-hydrazino) which may have a substituent such as a linear or branched alkyl group at the 5-position. 1,3-bis (hydrazinocarbonylalkyl) -5-mono (or 5,5-di) alkylhydantoin etc.] such as carbonylethyl) -5-isopropylhydantoin], 3,9-bis (hydrazinocarbonylalkyl)- 2,4,8,10-tetraoxaspiro [5.5] undecane (3,9-bis (2-hydrazinocarbonylethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane, etc. ) mono- or poly (hydrazinocarbonyl alkyl such) - oxaspiro C _6-20 alkane (mono tetraoxaspiro alkanes, Poriokisasu Roarukan, etc.) and the like are preferable.

  When such a carboxylic acid hydrazide is used, a stabilizing effect far surpassing that of conventional stabilizers is manifested by addition of a small amount, and a polyacetal resin composition excellent in molding processability (mold releasability and mold deposit prevention) Can be obtained. Further, the bleeding characteristics (blooming property) from the molded product can be greatly improved.

  The ratio of the aliphatic carboxylic acid hydrazide is, for example, 0.001 to 20 parts by weight, preferably 0.005 to 10 parts by weight, more preferably 0.01 to 5 parts by weight (100 parts by weight based on 100 parts by weight of the polyacetal resin. For example, it may be about 0.05 to 2 parts by weight.

  Even if the carboxylic acid hydrazide is used alone, it can give remarkable stability and processing stability to the polyacetal resin. Furthermore, the antioxidant, processing stabilizer, heat stabilizer, weather resistance (light) stabilizer, You may use it in combination with at least 1 type selected from the impact modifier, the glossiness control agent, the slidability improver, the coloring agent, and the filler.

  Many of the stabilizers (antioxidants, processing stabilizers, heat stabilizers and weathering (light) stabilizers) contain an ester bond [—C (═O) O—] as a structural unit in the molecule. . Even if the carboxylic acid hydrazide is used in combination with a stabilizer having such an ester bond, the polyacetal resin can be stabilized.

(Antioxidant)
Antioxidants include hindered phenol compounds and hindered amine compounds.

Examples of hindered phenol compounds include conventional phenol antioxidants or stabilizers such as monocyclic hindered phenol compounds (such as 2,6-di-t-butyl-p-cresol), hydrocarbon groups or sulfur. Polycyclic hindered phenol compounds linked with a group containing an atom [2,2'-methylenebis (4-methyl-6-tert-butylphenol), 4,4'-methylenebis (2,6-di-tert-butylphenol) ), 1,1,3-tris (2-methyl-4-hydroxy -5-t-butylphenyl) butane, 4,4'-butylidenebis (3-methyl -6-t-butylphenol) C _1-10, such as C _2-10 alkenylene such as alkylenebis to tetrakis (t-butylphenol); 4,4'-butylidenebis (3-methyl-6-t-butylphenol) Or dienylenebis to tetrakis (t-butylphenol) s; C _6-20 arylene such as 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene Or aralkylene bis to tetrakis (t-butylphenol) s; bis (t-butylphenols) linked by a group having a sulfur atom such as 4,4'-thiobis (3-methyl-6-t-butylphenol)], ester Hindered phenol compounds having a group or an amide group [n-octadecyl-3- (4′-hydroxy-3 ′, 5′-di-t-butylphenyl) propionate, n-octadecyl-2- (4′-hydroxy-) Having a C _2-10 alkylenecarbonyloxy group such as 3 ', 5'-di-t-butylphenyl) propionate 1,6-hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl- 5-methyl-4-hydroxyphenyl) propionate], pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] and the like bis to tetrakis ( t-butylphenol) s; 3,9-bis [2- {3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4,8 , 10-tetraoxaspiro [5.5] Available and heterocyclic groups and C _2-10 alkylene carbonyloxy group undecane Bis to tetrakis (t-butylphenol) s; 2-t-butyl-6- (3'-t-butyl-5'-methyl-2'-hydroxybenzyl) -4-methylphenyl acrylate, 2- [1- (2-Hydroxy-3,5-di-t-pentylphenyl) ethyl] t-alkylphenol having a C _3-10 alkenylcarbonyloxy group such as-4,6-di-t-pentylphenyl acrylate (for example, t- Hindered phenol compounds having a phosphonate group such as di-n-octadecyl-3,5-di-t-butyl-4-hydroxybenzylphosphonate; N, N'-hexamethylene Bis (3,5-di-t-butyl-4-hydroxy-dihydrocinnamamide, N, N′-ethylenebi [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionamide], N, N′-tetramethylenebis [3- (3,5-di-tert-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-tert-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) ) Propio 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 hindered phenol compounds having an amide unit. Among them, a phenol compound having a t-butyl (particularly, a plurality of t-butyl) groups (particularly a compound having a plurality of t-butylphenol moieties) is preferable. These hindered phenol compounds can be used alone or in combination of two or more.

Examples of the hindered amine compound include piperidine derivatives having a sterically hindered group, such as ester group-containing piperidine derivatives [4-acetoxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6. , 6-tetramethylpiperidine, 4-acryloyloxy-2,2,6,6-tetramethylpiperidine and the like aliphatic acyloxypiperidine ( _C2-20 aliphatic acyloxy-tetramethylpiperidine and the like); 4-benzoyloxy-2 , 2,6,6-aromatic acyl Oxypiperidine such tetramethylpiperidine (C _7-11 aromatic acyloxy - tetramethyl piperidine); bis (2,2,6,6-tetramethyl-4-piperidyl) oxalate, Bis (2,2,6,6-tetramethyl-4-piperidyl) malone Bis (2,2,6,6-tetramethyl-4-piperidyl) adipate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) adipate, bis (2,2,6,6) Aliphatic di- or tricarboxylic acid-bis or tripiperidyl esters ( _C2-20 aliphatic, such as -tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate Dicarboxylic acid-bispiperidyl ester, etc.); bis (2,2,6,6-tetramethyl-4-piperidyl) terephthalate, tris (2,2,6,6-tetramethyl-4-piperidyl) benzene-1,3 Aromatic di to tetracarboxylic acid-bis to tetrakispiperidyl esters such as aromatic di- or tricarboxylic acid-bis or Scan piperidyl ester) etc.], C _1-10 alkoxy piperidine (C _1-6 alkoxy such as an ether group-containing piperidine derivative [4-methoxy-2,2,6,6 - tetramethylpiperidine, etc.); C _5-8 cycloalkyloxy-piperidine such as 4-cyclohexyloxy-2,2,6,6-tetramethylpiperidine; aryloxypiperidine such as 4-phenoxy-2,2,6,6-tetramethylpiperidine; 4 C _6-10 aryl-C _1-4 alkyloxy-piperidine such as benzyloxy-2,2,6,6-tetramethylpiperidine; 1,2-bis (2,2,6,6-tetramethyl-4 -Piperidyloxy) ethane and other alkylenedioxybispiperidines (C _1-10 alkylenedioxy-bispiperidine etc.) ], An amide group-containing piperidine derivative [carbamoyloxypiperidine such as 4- (phenylcarbamoyloxy) -2,2,6,6-tetramethylpiperidine; bis (2,2,6,6-tetramethyl-4-piperidyl) Carbamoyloxy-substituted alkylenedioxy-bispiperidine etc. such as hexamethylene-1,6-dicarbamate] and the like. Also, a high molecular weight piperidine derivative polycondensate (dimethyl succinate-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly {6-[(1 , 1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl] [2- (2,2,6,6-tetramethylpiperidyl) amino] hexamethylene [4- (2,2,6,6-tetramethylpiperidyl) imino]} and the like. These hindered amine compounds can be used alone or in combination of two or more.

  These antioxidants can be used alone or in combination of two or more. The ratio of the antioxidant may be 0.001 to 5 parts by weight, preferably 0.005 to 3 parts by weight, and more preferably about 0.01 to 2 parts by weight with respect to 100 parts by weight of the polyacetal resin. Good.

(Processing stabilizer)
Examples of the processing stabilizer include at least one selected from (a) a long-chain fatty acid or a derivative thereof, (b) a polyoxyalkylene glycol, and (c) a silicone compound.

(A) Long chain fatty acid or derivative thereof The long chain fatty acid may be a saturated fatty acid or an unsaturated fatty acid. Also, those in which some hydrogen atoms are substituted with a substituent such as a hydroxyl group can be used. Examples of such long chain fatty acids include monovalent or divalent fatty acids having 10 or more carbon atoms, such as monovalent saturated fatty acids having 10 or more carbon atoms [capric acid, lauric acid, myristic acid, pentadecylic acid, palmitic acid, C _10-34 saturated fatty acids (preferably C _10-30 saturated fatty acids) such as stearic acid, arachidic acid, behenic acid and montanic acid], monovalent unsaturated fatty acids having 10 or more carbon atoms [oleic acid, linoleic acid , linolenic acid, arachidonic acid, an unsaturated C _10-34 fatty acids, such as erucic acid (preferably unsaturated C _10-30 fatty acids), having 10 or more divalent fatty acid carbon (dibasic fatty acid) [sebacate , dodecanedioic acid, tetradecanedioic acid, divalent C _10-30 saturated fatty acids (preferably divalent C _10-26 saturated fatty acids) such as Tapushia acid; decenoic diacid, C ₁₀ divalent, such as dodecendioic acid _-30 unsaturated fatty acids ( Mashiku divalent C _10-26 unsaturated fatty acids), etc.] can be exemplified. The fatty acids also include fatty acids having one or more hydroxyl groups in the molecule (for example, hydroxy saturated C _10-26 fatty acids such as 12-hydroxystearic acid). These fatty acids can be used alone or in combination of two or more. Of the fatty acids, monovalent C _10-26 saturated or unsaturated fatty acids and divalent C _10-20 saturated or unsaturated fatty acids are preferred.

  Derivatives of long chain fatty acids include fatty acid esters and fatty acid amides. The structure of the fatty acid ester is not particularly limited, and any of linear or branched fatty acid esters can be used. Esters of the long-chain fatty acid and alcohol (monoester, diester, triester, tetraester, etc.) And esters having one or more ester bonds). The alcohol constituting the long-chain fatty acid ester is not particularly limited and may be a monohydric alcohol, but usually a polyhydric alcohol is often used.

Examples of the polyhydric alcohol include polyhydric alcohols having about 2 to 8 carbon atoms, preferably about 2 to 6 carbon atoms or polymers thereof, such as alkylene glycol [C _2-8 alkylene glycol such as ethylene glycol, diethylene glycol, propylene glycol, etc. Diols such as (preferably C _2-6 alkylene glycol)]; triols such as glycerin, trimethylolpropane or derivatives thereof; tetraols such as pentaerythritol, sorbitan or derivatives thereof; Examples include alcohols alone or copolymers (for example, alkylene glycols alone or copolymers such as polyethylene glycol and polypropylene glycol, polyglycerin, dipentaerythritol, polypentaerythritol, etc.). The average degree of polymerization of the polyoxyalkylene glycol is 2 or more (for example, 2 to 500), preferably about 2 to 400 (for example, 2 to 360), and more preferably an average degree of polymerization of 16 or more (for example, 20 to 200). Degree). When polyoxyalkylene glycol is used as the polyhydric alcohol, the long-chain fatty acid constituting the ester is a fatty acid having 12 or more carbon atoms, such as a monovalent C _12-26 saturated or unsaturated fatty acid, and a divalent fatty acid. C _12-20 saturated or unsaturated fatty acids are preferably used. The said alcohol can also be used individually or in combination of 2 or more types.

  Examples of such long chain fatty acid esters include ethylene glycol mono or dipalmitate, ethylene glycol mono or distearate, ethylene glycol mono or dibehenate, ethylene glycol mono or dimantane, glycerol mono to tripalmitin. Acid ester, glycerol mono-tristearate, glycerol mono-tribehenate, glycerol mono-trimontanate, pentaerythritol mono-tetrapalmitate, pentaerythritol mono-tetrastearate, pentaerythritol mono-tetrabehenate Pentaerythritol mono to tetramontanate, polyglycerol tristearate, Methylolpropane monopalmitate, pentaerythritol monoundecylate, sorbitan monostearate, polyalkylene glycol (polyethylene glycol, polypropylene glycol, etc.) mono or dilaurate, mono or dipalmitate, mono or distearate, mono or dibehenate, mono Or dimontanate, mono or dioleate, mono or dilinoleate, etc. are mentioned.

  Among the derivatives, as the fatty acid amide, an acid amide (monoamide, bisamide, etc.) of the long chain fatty acid (monovalent or divalent long chain fatty acid) and an amine (monoamine, diamine, polyamine, etc.) can be used. . Of the acid amides, bisamide is particularly preferred.

  Monoamides include, for example, capric acid amide, lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, arachidic acid amide, behenic acid amide, montanic acid amide, etc. Examples thereof include primary acid amides of unsaturated fatty acids such as amides, secondary acid amides of saturated and / or unsaturated fatty acids and monoamines such as stearyl stearic acid amide and stearyl oleic acid amide.

Bisamides include bisamides of C _1-6 alkylene diamines (particularly C _1-2 alkylene diamines) and the above fatty acids. Specific examples thereof include ethylene diamine-dipalmitic acid amide, ethylene diamine-distearic acid amide (ethylene Bisstearylamide), hexamethylenediamine-distearic acid amide, ethylenediamine-dibehenic acid amide, ethylenediamine-dimantanoic acid amide, ethylenediamine-dioleic acid amide, ethylenediamine-dierucic acid amide, and the like, and ethylenediamine- (stearic acid amide) olein A bisamide having a structure in which a different acyl group is bonded to an amine moiety of an alkylenediamine such as an acid amide can also be used. In the acid amide, the fatty acid constituting the acid amide is preferably a saturated fatty acid.

  These long chain fatty acids or derivatives thereof can be used alone or in combination of two or more.

(B) Polyoxyalkylene glycol Polyoxyalkylene glycol includes an alkylene glycol [for example, C _2-6 alkylene glycol (preferably C _2-4 alkylene glycol) such as ethylene glycol, propylene glycol, tetramethylene glycol, etc.]. Or a copolymer, those derivatives, etc. are contained.

Specific examples of the polyoxyalkylene glycol include poly C _2-6 oxyalkylene glycol (preferably poly C _2-4 oxyalkylene glycol) such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol, and polyoxyethylene-polyoxypropylene. Examples thereof include copolymers (such as random or block copolymers), copolymers such as polyoxyethylene polyoxypropylene glyceryl ether, polyoxyethylene polyoxypropylene monobutyl ether, and the like. Of these, polymers having oxyethylene units, such as polyethylene glycol, polyoxyethylene polyoxypropylene copolymers, and derivatives thereof are preferable.

The number average molecular weight of the polyoxyalkylene glycol is 3 × 10 ² to 1 × 10 ⁶ (for example, 5 × 10 ^{2 to} 5 × 10 ⁵ ), preferably 1 × 10 ³ to 1 × 10 ⁵ (for example, 1 × 10 ⁵ ). ^{3 to} 5 × 10 ⁴ ). Polyoxyalkylene glycols can be used alone or in combination of two or more.

(C) Silicone compound The silicone compound includes (poly) organosiloxane. (Poly) organosiloxanes include monoalkylsiloxanes such as dialkylsiloxanes (eg, dimethylsiloxane), alkylarylsiloxanes (eg, phenylmethylsiloxane), diarylsiloxanes (eg, diphenylsiloxane), and homopolymers thereof. (For example, polydimethylsiloxane, polyphenylmethylsiloxane, etc.) or a copolymer can be exemplified. The polyorganosiloxane may be an oligomer.

  In addition, (poly) organosiloxane has an epoxy group, hydroxyl group, alkoxy group, carboxyl group, amino group or substituted amino group (such as dialkylamino group), ether group, vinyl group, ) Modified (poly) organosiloxane having a substituent such as acryloyl group (for example, modified silicone) is also included. These silicone compounds can be used alone or in combination of two or more.

  The ratio of the processing stabilizer is selected from, for example, 0.001 to 10 parts by weight, preferably 0.01 to 5 parts by weight, and more preferably about 0.03 to 3 parts by weight with respect to 100 parts by weight of the polyacetal resin. In particular, it may be about 0.03 to 2 parts by weight.

(Heat resistance stabilizer)
The heat stabilizer includes (a) basic nitrogen compound, (b) organic carboxylic acid or organic carboxylic acid metal salt, (c) alkali or alkaline earth metal compound, (d) hydrotalcite, (e) zeolite And (f) a phosphine compound.

(a) Basic nitrogen compound As the basic nitrogen compound, at least one selected from aminotriazine compounds, guanidine compounds, urea compounds, amino acid compounds, amino alcohol compounds, imide compounds, amide compounds and hydrazine compounds can be used.

  Aminotriazine compounds include melamine or derivatives thereof [melamine, melamine condensates (melam, melem, melon, etc.)], guanamine or derivatives thereof, and aminotriazine resins [melamine co-condensation resins (melamine-formaldehyde resin, phenol-melamine). Resin, melamine-phenol-formaldehyde resin, benzoguanamine-melamine resin, aromatic polyamine-melamine resin, etc.) and guanamine co-condensation resins (benzoguanamine-formaldehyde resin, benzoguanamine-phenol-formaldehyde resin, etc.)].

Among the aminotriazine compounds, guanamine derivatives include aliphatic guanamine compounds [monoguanamines (C _1-24 alkyl-substituted guanamines such as valerologamine, caproguanamine, heptanoguanamine, capriloganamin, stearanamin, etc.) , Alkylene bisguanamines (such as C _1-24 alkylene-bisguanamines such as succinoguanamine, glutaloganamin, adipoguanamine, pimeloganamin, suboguanamine, azeroguanamine, sebacoguanamine, etc.), alicyclic guanamine Compounds [monoguanamines (cyclohexanecarboguanamine, norbornenecarboguanamine, cyclohexenecarboguanamine, norbornanecarboguanamine and their functional group substituents (alkyl group, hydroxyl group, amino group) Group, acetamino group, nitrile group, carboxyl group, alkoxycarbonyl group, carbamoyl group, alkoxy group, phenyl group, cumyl group, hydroxyphenyl group and other functional groups substituted with 1 to 3 cycloalkane residues) ), Etc.], aromatic guanamine compounds [monoguanamines (benzoguanamine and functional group substituents thereof (alkyl group, aryl group, hydroxyl group, amino group, acetamino group, nitrile group, carboxyl group, alkoxycarbonyl group, carbamoyl group, Derivatives in which 1 to 5 functional groups such as alkoxy group, phenyl group, cumyl group, and hydroxyphenyl group are substituted on the phenyl residue of benzoguanamine: for example, o-, m- or p-toruguanamine, o-, m- P-xyloganamin, o-, m- or p-pheny Benzoguanamine, o-, m- or p-hydroxybenzoguanamine, 4- (4'-hydroxyphenyl) benzoguanamine, o-, m- or p-nitrile benzoguanamine, 3,5-dimethyl-4-hydroxybenzoguanamine, 3,5- Di-t-butyl-4-hydroxybenzoguanamine, etc.), α- or β-naphthoguanamine and their functional group-substituted derivatives, polyguanamines (phthaloguanamine, isophthaloguanamine, terephthaloguanamine, naphthalenediguanamine, biphenylene diguanamine) ), Aralkyl or aralkylenguanamines (phenylacetoguanamine, β-phenylpropioguanamine, o-, m- or p-xylylenebisguanamine, etc.)], etc.], heteroatom-containing guanamine compounds [acetals] -Containing guanamines (2,4-diamino-6- (3,3-dimethoxypropyl-s-triazine etc.), dioxane ring-containing guanamines ([2- (4 ', 6'-diamino-s-triazine-2' -Yl) ethyl] -1,3-dioxane, [2- (4 ′, 6′-diamino-s-triazin-2′-yl) ethyl] -4-ethyl-4-hydroxymethyl-1,3-dioxane ), Tetraoxospiro ring-containing guanamines (CTU-guanamine, CMTU-guanamine, etc.), isocyanuric ring-containing guanamines (1,3,5-tris [2- (4 ′, 6′-diamino-s-triazine-) 2'-yl) ethyl] isocyanurate, 1,3,5-tris [3- (4 ', 6'-diamino-s-triazin-2'-yl) propyl] isocyanurate), imidazole Containing (such as guanamine compounds of JP 47-41120 JP) guanamines, and the like guanamine compounds described in JP-A No. 2000-154181. Further, compounds in which the alkoxymethyl group of the above melamine, melamine derivative, or guanamine compound is substituted with an amino group [for example, mono to hexamethoxymethyl melamine, mono to tetramethoxymethyl benzoguanamine, mono to octamethoxymethyl CTU-guanamine, etc.] Etc. are also included.

  Guanidine compounds include, for example, acyclic guanidine (glycosiamine, guanolin, guanidine, cyanoguanidine, etc.), cyclic guanidine (glycocyanidins such as glycocyanidine, creatinine; oxalylguanidine, oxalylguanidine such as 2,4-diiminoparabanic acid, etc. Or an imino group-substituted urazole compound (iminourasol, guanazine, etc.); isocyanuric acid imides (isoammelide, isoammeline, etc.); malonylguanidine, tartronylguanidine; mesoxalylguanidine, etc. Is mentioned.

Examples of the urea compound include non-cyclic urea compounds [N-substituted urea substituted with a substituent such as urea and an alkyl group, acyclic urea condensates (multimers of urea such as biuret and biurea; methylene diurea, form Condensates of urea and aldehyde compounds such as nitrogen, oligo or poly C _1-12 alkylene ureas (such as oligo or polynonamethylene urea), etc.], cyclic urea compounds [cyclic monoureides such as C _1-10 alkylene ureas, etc. (Ethylene urea, crotonylidene urea, etc.), arylene urea (eg imatin), diuretic acid ureido (parabanic acid, barbituric acid, isocyanuric acid, uramil etc.), β-aldehyde acid ureido (uracil, thymine, urazole etc.), α-oxyacid ureido (hydantoins such as hydantoin; 5-methyl 5 straight or branched C _1-6 alkyl such as Dantoin - hydantoin; 5-phenyl-hydantoin, 5- (o-, m-, or p- hydroxyphenyl) hydantoin, 5- (o-, m-, or p -Aminophenyl) Hydantoin and other aryl groups optionally having a substituent such as hydroxyl group or amino group; 5-C _6-10 arylhydantoin; 5-C _6-10 arylC ₁ such as 5- _{benzylhydantoin -4} alkyl-hydantoins; 5,5-di linear or branched C _1-6 alkyl-hydantoins such as 5,5-dimethylhydantoin; 5-linear or branched C _1- such as 5-methyl-5-phenylhydantoin _6- alkyl-5-C _6-10 arylhydantoins; 5,5-diC _6-10 arylhydantoins such as 5,5-diphenylhydantoin; 5,5-dibenzylhydanin 5,5-bis (C _6-10 arylC _1-4 alkyl) hydantoins such as toins; C _1-10 alkylene-bishydantoins such as pentamethylenebishydantoins; allantoin or metal salts thereof (Al such as allantoin dihydroxyaluminum salts) Cyclic diureido, such as uric acid, alkyl-substituted uric acid, acetylene urea (glycoluril) or derivatives thereof (mono to tetra (C _1-4 alkoxy C _1-4 alkyl) glycoluril, etc.), clothylidene diurea , Α-oxyacid diureides (such as 1,1′-methylenebis (5,5-dimethylhydantoin)), diureas such as p-urazine, dicarboxylic acid diureides (such as alloxanthin and purpuric acid), and the like. .

  As amino acids, α-amino acids [monoamino monocarboxylic acids (glycine, alanine, valine, norvaline, leucine, norleucine, isoleucine, phenylalanine, tyrosine, diiodotyrosine, sulinamine, threonine, serine, proline, hydroxyproline, tryptophan, Methionine, cystine, cysteine, citrulline, α-aminobutyric acid, hexahydropicolinic acid, theanine, o- or m-tyrosine), monoaminodicarboxylic acids (aspartic acid, glutamic acid, asparagine, glutamine, hexahydrodipicolinic acid, hexahydro Quinolinic acid etc.), diaminomonocarboxylic acids (lysine, hydroxylysine, arginine, histidine etc.)], β-amino acids (β-alanine, β-aminobutyric acid, hexahydro) Cincomeronic acid and the like), γ-amino acids (γ-aminobutyric acid and the like), δ-amino acids (δ-amino-n-valeric acid and the like), and the like. The amino acids may be any of D-form, L-form, and DL-form, and the carboxyl group is metal chloride (alkali metal salt, alkaline earth metal salt, etc.), amidation, hydrazide. In addition, esterified (methyl ester, ethyl ester, etc.) amino acid derivatives are also included.

Amino alcohol compounds include monoethanolamine, diethanolamine, 2-amino-1-butanol, 2-amino-2-methyl-1-propanol, 2-amino-2-methyl-1,3-propanediol, 2-amino Examples include amino C _1-10 aliphatic mono- or polyols such as 2-ethyl-1,3-propanediol and tris (hydroxymethyl) aminomethane.

  As the imide compound, aromatic polycarboxylic imides such as phthalic imide, trimellitic imide, and pyromellitic imide can be used.

  Amide compounds include aliphatic carboxylic acid amides (such as malonamide, adipic acid amide, sebacic acid amide, dodecanedioic acid amide), cyclic carboxylic acid amides (such as ε-caprolactam), and aromatic carboxylic acid amide (benzoic acid amide). , O-, m- or p-aminobenzamide, isophthalic acid diamide, terephthalic acid amide, etc.), polyamide resin [for example, nylon 3 (poly β-alanine), nylon 46, nylon 6, nylon 66, nylon 11, nylon 12, nylon MXD6, nylon 6-10, nylon 6-11, nylon 6-12, nylon 6-66-610, nylon 9T, etc.], polyesteramide, polyamideimide, polyurethane, poly (meta ) Acrylic acid amide homopolymer or copolymer [US Patent No. Polymers described in Japanese Patent No. 5011890], poly (vinyl lactam) homopolymers or copolymers [poly (N-vinylpyrrolidone) homopolymers or copolymers, etc.] (for example, JP-A-55-52338, US A homopolymer or a copolymer described in Japanese Patent No. 3204014), poly (N-vinylcarboxylic acid amide), a copolymer of N-vinylcarboxylic acid amide and another vinyl monomer (for example, JP-A-2001-247745). , JP-A-2001-131386, JP-A-8-311302, JP-A-59-86614, US Pat. No. 5,455,042, US Pat. No. 5,407,996, US Pat. No. 5,338,815. Or a copolymer thereof).

  The hydrazine compound includes a carboxylic acid hydrazide, which is different from the hydrazide of the heteroatom-containing aliphatic carboxylic acid, and the carboxylic acid constituting the carboxylic acid hydrazide is substantially free of heteroatoms. . Examples of such hydrazine compounds include fatty acid hydrazides (lauric acid hydrazide, stearic acid hydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, etc.), aromatic carboxylic acid hydrazides (benzoic acid hydrazide, naphthoic acid hydrazide, Phthalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, naphthalenedicarboxylic acid dihydrazide, p-hydroxybenzoic acid hydrazide, salicylic acid hydrazide and the like.

(b) Organic carboxylic acid or organic carboxylic acid metal salt As the organic carboxylic acid, a carboxyl group-containing compound having a pKa of 3.6 or more can be used. Examples of such organic carboxylic acids include organic carboxylic acids described in JP-A No. 2000-239484.

  Examples of organic carboxylic acid metal salts include salts of organic carboxylic acids and metals (alkali metals such as Li, Na, and K; alkaline earth metals such as Mg and Ca; transition metals such as Zn).

The organic carboxylic acid constituting the metal salt may be either a low molecule or a polymer, and the long chain saturated or unsaturated aliphatic carboxylic acid exemplified in the section of the long chain fatty acid, carbon number 10 Less than lower saturated or unsaturated aliphatic carboxylic acids, polymers of unsaturated aliphatic carboxylic acids, and the like can also be used. Further, these aliphatic carboxylic acids may have a hydroxyl group. Examples of the lower saturated aliphatic carboxylic acid include saturated C _1-9 monocarboxylic acid (acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, pivalic acid, caproic acid, caprylic acid, etc.), saturated C _2-9 dicarboxylic acids (oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, corkic acid, azelaic acid, etc.) and their oxyacids (glycolic acid, lactic acid, glyceric acid, hydroxybutyric acid, citric acid) Acid) and the like.

Examples of lower unsaturated aliphatic carboxylic acids include unsaturated C _3-9 monocarboxylic acids [(meth) acrylic acid, crotonic acid, isocrotonic acid, etc.], unsaturated C _4-9 dicarboxylic acids (maleic acid, fumaric acid, etc.) ), And these oxyacids (propiolic acid and the like).

Moreover, as a polymer of unsaturated aliphatic carboxylic acid, polymerizable unsaturated carboxylic acid [α, β-ethylenically unsaturated carboxylic acid, for example, polymerizable unsaturated monocarboxylic acid such as (meth) acrylic acid, polymerization Unsaturated polyvalent carboxylic acids (such as itaconic acid, maleic acid, fumaric acid), acid anhydrides or monoesters (such as mono-C _1-10 alkyl esters such as monoethyl maleate)] and olefins And a copolymer with (α-C _2-10 olefin such as ethylene and propylene).

  These organic carboxylic acids or organic carboxylic acid metal salts can be used alone or in combination of two or more.

  Preferred organic metal carboxylates are alkali metal organic carboxylates (lithium citrate, potassium citrate, sodium citrate, lithium stearate, lithium 12-hydroxystearate, etc.), alkaline earth metal organic carboxylates (acetic acid Magnesium, calcium acetate, magnesium citrate, calcium citrate, calcium stearate, magnesium stearate, 12-hydroxy magnesium stearate, 12-hydroxy calcium stearate, etc.), ionomer resin (the polymerizable unsaturated polyvalent carboxylic acid and olefin) A resin in which at least a part of the carboxyl groups contained in the copolymer is neutralized by the metal ions). The ionomer resin is commercially available, for example, as ACLYN (manufactured by Allied Signal), Himiran (manufactured by Mitsui DuPont Polychemical Co., Ltd.), Surlyn (manufactured by DuPont).

  Among the metal salts, alkaline earth metal salts such as calcium citrate, magnesium citrate, magnesium stearate, calcium stearate, 12-hydroxymagnesium stearate, and 12-hydroxycalcium stearate are preferable from the viewpoint of stabilizing effect. In particular, alkaline earth metal salts of oxyacids such as calcium citrate and magnesium citrate are preferred.

(c) Alkali or alkaline earth metal compounds Alkali or alkaline earth metal compounds include metal oxides such as CaO and MgO, metal hydroxides such as LiOH, Ca (OH) ₂ and Mg (OH) ₂ , metals Contains inorganic compounds such as inorganic acid salts (such as metal carbonates such as Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , CaCO ₃ , MgCO ₃ , inorganic acid salts such as borates and phosphates, etc.) In particular, metal oxides and metal hydroxides are preferred. Of the compounds, alkaline earth metal compounds are preferred.

  These alkali or alkaline earth metal compounds can be used alone or in combination of two or more.

(d) Hydrotalcite Hydrotalcite includes hydrotalcites described in JP-A-60-1241 and JP-A-9-59475, for example, hydrotalcite represented by the following formula: A compound etc. can be used.

[M ²⁺ _1-x M ³⁺ _x (OH) ₂ ] ^{x +} [A ^n- _{x / n} · mH ₂ O] ^x-
(In the formula, M ²⁺ represents a divalent metal ion such as Mg ²⁺ , Mn ²⁺ , Fe ²⁺ , and Co ²⁺ , and M ³⁺ represents ³ such as Al ³⁺ , Fe ³⁺ , and Cr ^3+. A ^n- represents an n-valent (particularly monovalent or divalent) anion such as CO ₃ ²⁻ , OH ⁻ , HPO ₄ ²⁻ , SO ₄ ^2−, etc. x is 0 <x <0.5 and m is 0 ≦ m <1.)
These hydrotalcites can be used alone or in combination of two or more.

  Hydrotalcite is available from Kyowa Chemical Industry Co., Ltd. as “DHT-4A”, “DHT-4A-2”, “Alkamizer”, and the like.

(e) Zeolite Zeolite is not particularly limited, but zeolite other than H type, for example, zeolite described in JP-A-7-62142 [the smallest unit cell is alkali and / or alkaline earth metal crystallinity Zeolite that is an aluminosilicate (A-type, X-type, Y-type, L-type, ZSM-type zeolite, mordenite zeolite; natural zeolite such as chabazite, mordenite, faujasite, etc.) and the like can be used.

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

  In addition, A-type zeolite is "Zeoram series (A-3, A-4, A-5)", "Zeostar series (KA-100P, NA-100P, CA-100P)" etc., and X Type Zeolite is “Zeoram Series (F-9)”, “Zeostar Series (NX-100P)”, Y Type Zeolite is “HSZ Series (320NAA)”, etc. Tosoh Corporation, Nippon Chemical Industry Co., Ltd. ).

(f) Phosphine compound The phosphine compound includes alkyl phosphine (for example, tri-C _1-10 alkyl phosphine such as triethyl phosphine, tripropyl phosphine, tributyl phosphine), cycloalkyl phosphine (for example, tri-C ₅ such as tricyclohexyl phosphine). _-12 cycloalkylphosphine, etc.), arylphosphine (eg, triphenylphosphine, p-tolyldiphenylphosphine, di-p-tolylphenylphosphine, tri-m-aminophenylphosphine, tri (2,4-dimethylphenyl) phosphine, Tri-C which may have a substituent such as an amino group such as tri (2,4,6-trimethylphenyl) phosphine and tri (o-, m- or p-tolyl) phosphine and a C _1-4 alkyl group. _6-12 aryl phosphine ), Aralkyl phosphine (e.g., tri (o-, such as tri (C _6-12 aryl C _1-4 alkyl) phosphine such as m- or p- anisylphosphine), arylalkenyl phosphine (e.g., diphenyl vinyl phosphine, allyl Mono- or di-C _6-12 aryl-di or mono-C _2-10 alkenyl phosphine such as diphenylphosphine), arylaralkyl phosphines (eg p-anisyl diphenylphosphine, di (p-anisyl) phenylphosphine mono or Di C _6-12 aryl-di or mono (C _6-12 aryl C _1-4 alkyl) phosphine; may have a substituent such as C _1-10 alkyl group such as methylphenyl-p-anisylphosphine good C _6-12 aryl - such as (C _6-12 aryl C _1-4 alkyl) phosphine), bisphosphine example If, and 1,4-bis (diphenylphosphino) bis (di-C _6-12 aryl phosphino) such as butane C _1-10 alkane] phosphine compound, and others. These phosphine compounds, alone or in Two or more types can be used in combination.

  These heat stabilizers can be used alone or in combination of two or more. In particular, when a combination of a basic nitrogen-containing compound and at least one selected from an organic carboxylic acid metal salt, an alkali or alkaline earth metal compound, hydrotalcite, zeolite, and a phosphine compound is used, heat resistance is stabilized in a smaller amount. Sex can also be imparted. In addition, the resin composition of this invention can also improve heat-resistant stability, even if it does not contain a phosphorus flame retardant substantially.

  When the resin composition contains a heat stabilizer, the proportion of the heat stabilizer is, for example, 0.001 to 10 parts by weight, preferably 0.001 to 5 parts by weight (particularly 0 to 100 parts by weight of the polyacetal resin). .01 to 2 parts by weight). Of the heat stabilizer, a small amount of hydrazine compounds (fatty acid hydrazide and aromatic carboxylic acid hydrazide) is used because it may exude from the polyacetal resin composition or impair the molding stability of the resin composition. Is preferred. The ratio of the hydrazine compound is usually 1 part by weight or less (for example, about 0 to 1 part by weight), preferably 0.001 to 1 part by weight, more preferably 0.005 to 100 parts by weight of the polyacetal resin. It may be 0.8 part by weight (for example, about 0.005 to 0.08 part by weight).

(Weather-resistant (light) stabilizer)
Weather resistance (light) stabilizers include (a) benzotriazole compounds, (b) benzophenone compounds, (c) aromatic benzoate compounds, (d) cyanoacrylate compounds, (e) oxalic acid anilide compounds, (f) hydroxyaryl-1,3,5-triazine compounds, and (g) hindered amine compounds.

(a) Benzotriazole compounds As the benzotriazole compounds, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di (t-butyl) ) Phenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di (t-amyl) phenyl) benzotriazole, 2- (2'-hydroxy-3', 5'-diisoamylphenyl) benzo Benzotriazoles having a hydroxyl group such as triazole and an aryl group substituted with a C _1-6 alkyl group; 2- [2′-hydroxy-3 ′, 5′-bis (α, α-dimethylbenzyl) phenyl] benzo Benzotriazoles having an aryl group substituted with a hydroxyl group and an aralkyl (or aryl) group such as triazole; 2- ( '- such as hydroxy-4'-octoxyphenyl) benzotriazole having a hydroxyl group and an alkoxy (C _1-12 alkoxy) aryl groups substituted with groups such as benzotriazole.

Among these benzotriazole compounds, in particular, benzotriazoles having a hydroxyl group and a C _3-6 alkyl group-substituted C _6-10 aryl (particularly phenyl) group, and a hydroxyl group and a C _6-10 aryl-C _1- Benzotriazoles having a _6- alkyl (particularly phenyl-C _1-4 alkyl) group-substituted aryl group are preferred.

(b) Benzophenone compounds As benzophenone compounds, benzophenones having a plurality of hydroxyl groups (di to tetrahydroxybenzophenones such as 2,4-dihydroxybenzophenone; hydroxyl groups such as 2-hydroxy-4-oxybenzylbenzophenone, and Benzophenones having a hydroxyl-substituted aryl or aralkyl group and the like; benzophenones having a hydroxyl group and an alkoxy (C _1-16 alkoxy) group (2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2 -Hydroxy-4-dodecyloxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy 4, such as methoxy-5-sulfobenzophenone), and the like.

Of these benzophenone compounds, benzophenones having a hydroxyl group-substituted C _6-10 aryl (or C _6-10 aryl-C _1-4 alkyl) group with a hydroxyl group, particularly a hydroxyl group-substituted phenyl-C with a hydroxyl group. Benzophenones having a _1-4 alkyl group are preferred.

(c) Aromatic benzoate compounds As the aromatic benzoate compounds, alkylaryl salicylates (particularly, alkylphenyl salicylates) such as pt-butylphenyl salicylate and p-octylphenyl salicylate can be mentioned.

(d) Cyanoacrylate compounds As cyanoacrylate compounds, cyano group-containing diaryl acrylates such as 2-ethylhexyl-2-cyano-3,3-diphenyl acrylate, ethyl-2-cyano-3,3-diphenyl acrylate ( In particular, cyano group-containing diphenyl acrylate and the like).

(e) Oxalic acid anilide compound As the oxalic acid anilide compound, N- (2-ethylphenyl) -N '-(2-ethoxy-5-t-butylphenyl) oxalic acid diamide, N- (2-ethyl) Examples include oxalic acid diamides having an aryl group (such as a phenyl group) which may be substituted on a nitrogen atom, such as phenyl) -N ′-(2-ethoxy-phenyl) oxalic acid diamide.

(f) Hydroxyaryl-1,3,5-triazine compound As the hydroxyaryl-1,3,5-triazine compound, 2,4-diC _6-10 aryl-6- (mono or dihydroxy C _{6- 10} aryl) -1,3,5-triazine [C _1-10 alkyl group, C _1-18 alkoxy group, C _1-10 alkoxy C _1-10 alkoxy group, C _6-10 aryloxy group on the aryl group, C 2,4-diC _6-10 aryl-6- (mono or dihydroxy C _6-10 aryl) -1,3,5 which may have a substituent such as _6-10 aryl C _1-6 alkoxy group -Triazines such as 2,4-diphenyl-6- (2-hydroxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2,4-dihydroxyphenyl) -1,3,5 -Hydroxyaryl triazines such as triazines; 2 , 4-Diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-ethoxyphenyl) -1,3,5 Triazine, 2,4-diphenyl-6- (2-hydroxy-4-propoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-butoxyphenyl) -1 , 3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-) Octyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, these 2,4-diazines Eniru 6- (2-hydroxy - alkoxyphenyl) corresponding to the 1,3,5-triazine 2,4-di (p- tolyl or 2 ', 4'-dimethylphenyl) 6- (2-hydroxy -C _1-16 alkoxyphenyl) -1,3,5-triazine and other hydroxyalkoxyaryltriazines; 2,4-diphenyl-6- (2-hydroxy-4-benzyloxyphenyl) -1,3,5-triazine, 2 Hydroxyaralkyloxyaryl triazines such as 1,4-di (p-tolyl or 2 ′, 4′-dimethylphenyl) -6- (2-hydroxy-4-benzyloxyphenyl) -1,3,5-triazine; 4-diphenyl-6- (2-hydroxy-4- (2-butoxyethoxy) phenyl) -1,3,5-triazine, 2,4-di-p-tolyl-6 Such hydroxyalkoxy alkoxyaryl triazines such as (2-hydroxy-4- (2-hexyl) phenyl) -1,3,5-triazine. Of these, hydroxyphenyl-1,3,5-triazine compounds in which aryl is phenyl may be used.

(g) Hindered amine compounds As the hindered amine compounds, the hindered amine compounds exemplified in the section of the antioxidant can be used.

  These weather resistance (light) stabilizers may be used alone, or two or more of the same or different weather resistance (light) stabilizers may be used in combination.

  In addition, it is preferable to use (g) a hindered amine compound in combination with other weathering (light) stabilizers, and it is particularly preferable to use (a) a benzotriazole compound and (g) a hindered amine compound in combination. . The ratio (weight ratio) of the hindered amine compound (g) to the other weather resistance (light) stabilizer (particularly the benzotriazole compound) is, for example, hindered amine compound / other weather (light) stabilizer = 0/100 to It may be about 80/20, preferably 10/90 to 70/30, and more preferably about 20/80 to 60/40.

  The proportion of the weathering (light) stabilizer is, for example, 0 to 5 parts by weight (for example, 0.01 to 5 parts by weight), preferably 0.1 to 4 parts by weight, more preferably 100 parts by weight of the polyacetal resin. Is about 0.1 to 2 parts by weight.

(Coloring agent)
As the colorant, various dyes or pigments can be used. The dye is preferably a solvent dye, and examples thereof include azo dyes, anthraquinone dyes, phthalocyanine dyes, and naphthoquinone dyes. As the pigment, any of inorganic pigments and organic pigments can be used.

  Inorganic pigments include titanium pigments, zinc pigments, carbon black (furnace black, channel black, acetylene black, ketjen black, etc.), iron pigments, molybdenum pigments, cadmium pigments, lead pigments, cobalt pigments And aluminum pigments.

  Examples of the organic pigment include azo pigments, anthraquinone pigments, phthalocyanine pigments, quinacridone pigments, perylene pigments, perinone pigments, isoindoline pigments, dioxazine pigments, and selenium pigments.

  The above colorants may be used alone or in combination with a plurality of colorants. When a colorant having a high light shielding effect (carbon black, titanium white (titanium oxide), phthalocyanine pigment, perylene pigment (particularly carbon black, perylene black pigment), etc.) is used, weather resistance (light) resistance can be improved. .

  Content of a coloring agent is 0-5 weight part (for example, 0.01-5 weight part) with respect to 100 weight part of polyacetal resin, for example, Preferably it is 0.1-4 weight part, More preferably, it is 0.00. About 1 to 2 parts by weight.

In the polyacetal resin composition of the present invention, if necessary, conventional additives such as antioxidants (phosphorus-based, sulfur-based, hydroquinone-based, quinoline-based antioxidants, etc.), specific carboxylic acids (JP-A-2000) Carboxylic acid described in JP-A-239484), impact resistance improver (at least one selected from thermoplastic polyurethane resin, acrylic core-shell polymer, thermoplastic polyester elastomer, and styrene elastomer), gloss Control agent [at least one selected from acrylic resins ( _mono or copolymers of C _1-10 alkyl (meth) acrylates such as polymethyl methacrylate) and styrene resins (mono or copolymers of styrene, etc.)] , Sliding property improver [olefin polymer, silicone resin, and fluorine resin At least one selected from the above], release agents, nucleating agents, antistatic agents, flame retardants, foaming agents, surfactants, antibacterial agents, antifungal agents, fragrances, fragrances, various polymers [polycarbonate resins, polyolefins Elastomer or resin, polyvinyl alcohol resin, aliphatic polyester resin (poly L-lactic acid, poly D-lactic acid, poly D / L-lactic acid, polyglycolic acid, glycolic acid and lactic acid (D-, L- or D / L-lactic acid)), etc.], fillers, etc. may be added singly or in combination of two or more.

  Moreover, you may mix | blend fillers, such as a conventional fiber form, plate shape, and a granular form, individually or in combination of 2 or more types as needed in order to improve the performance of the molded article of this invention. Examples of the fibrous filler include inorganic fibers (glass fiber, carbon fiber, boron fiber, potassium titanate fiber (whisker), etc.), organic fiber (amide fiber, etc.) and the like. Examples of the plate-like filler include glass flakes, mica, graphite, and various metal foils. Powdered fillers include metal oxides (such as zinc oxide and alumina), sulfates (such as calcium sulfate and magnesium sulfate), carbonates (such as calcium carbonate), and glasses (such as milled fiber, glass beads, and glass balloons). , Silicates (talc, kaolin, silica, diatomaceous earth, clay, wollastonite, etc.), sulfides (molybdenum disulfide, tungsten disulfide, etc.), carbides (fluorinated graphite, silicon carbide, etc.), boron nitride, etc. it can.

(Production method of polyacetal resin composition)
The polyacetal resin composition of the present invention may be a granular mixture or a molten mixture. The polyacetal resin, a hydrazide of a specific heteroatom-containing aliphatic carboxylic acid, and other additives [stabilizer (antioxidant) if necessary. Agent, processing stabilizer, heat resistance stabilizer, weather resistance (light) stabilizer), impact resistance improver, gloss control agent, slidability improver, colorant and / or filler] in a conventional manner. Can be prepared. For example, (1) a method in which all components are fed from a main feed port, kneaded by an extruder (such as a single screw or twin screw extruder) and extruded to prepare pellets, and (2) the specific carvone Components containing no acid hydrazide (polyacetal resin, other additives, etc.) from the main feed port, and components containing at least the specific carboxylic acid hydrazide (as other components, polyacetal resin, other additives, etc.) A method of forming a pellet after feeding through a side feed port and kneading and extruding with an extruder, and (3) a component containing a part of the specific carboxylic acid hydrazide (as other components, polyacetal resin, other additions) Agent) from the main feed port, and the remaining specific carboxylic acid hydrazide and, if necessary, the heat stabilizer carboxylic acid hydride. A method in which a component containing a razide (as other components, such as polyacetal resin and other additives) is fed from a side feed port and kneaded and extruded by an extruder to prepare pellets, and (4) once different in composition Prepare pellets (masterbatch), mix (dilut) the pellets with a predetermined amount, and use them for molding to obtain molded products with the specified composition. (5) Sprinkle the specific carboxylic acid hydrazide on the pellets of polyacetal resin For example, a method of obtaining a molded product having a predetermined composition by molding after coexistence or adhesion by coating (surface coating or the like) or the like can be employed.

  Among these methods, the above methods (1), (2) and (3) are preferable, and it is particularly preferable to melt and mix in a single or twin screw extruder having one or more devolatilization vent ports. Further, the side feed of the carboxylic acid hydrazide is possible from any of the feed ports before and after the devolatilization vent port. Furthermore, in the extrusion preparation process, processing aids such as water and / or alcohols (methanol, ethanol, isopropyl alcohol, n-propyl alcohol, etc.) are injected from the feed port before the preblend or devolatilization vent port, and degassed. The amount of formaldehyde generated from the molded product can be further reduced by devolatilizing and removing volatile components including water and / or alcohols from the volatile vent port. The ratio of water and / or alcohols as the processing aid is not particularly limited, and can usually be selected from the range of 0 to 20 parts by weight, preferably 0.01 to 10 parts per 100 parts by weight of the polyacetal resin. It may be about 0.1 to 5 parts by weight, more preferably about 0.1 to 5 parts by weight.

  In particular, when the polyacetal resin and the heteroatom-containing aliphatic carboxylic acid hydrazide are melt-mixed by an extruder, the formaldehyde reaction trapping rate is limited while the formaldehyde reaction trapping rate of the hydrazide is high. The extrusion preparation method in which at least a part or all of the hydrazide is side-fed from the side feed port of the extruder, and / or the melt-kneading time (average residence time) in the extruder is short, for example, 300 seconds or less (for example, 5 to 300 seconds), preferably 250 seconds or less (for example, about 10 to 250 seconds), more preferably 200 seconds or less (for example, about 10 to 200 seconds), particularly about 10 to 150 seconds. Is preferably used.

  In the preparation of a composition used for a molded product, a granular material of a polyacetal resin as a substrate (for example, a granular material obtained by pulverizing part or all of a polyacetal resin) and other components (the specific carboxylic acid hydrazide). , And other additives (stabilizers, impact modifiers, gloss control agents, slidability improvers, colorants and / or fillers, etc.) are mixed and melt kneaded to disperse the additives. It is advantageous to improve.

  The polyacetal resin composition of the present invention can remarkably suppress the formation of formaldehyde due to oxidation or thermal decomposition of the polyacetal resin, particularly in the molding process (particularly melt molding process), and can improve the working environment. In addition, adhesion of decomposition products and additives to the mold (mold deposit) and exudation of decomposition products and additives from the molded product can be remarkably suppressed, and various problems during molding can be improved.

(Molded body)
The molded body formed with the said resin composition is also contained in this invention. The molded body contains a combination of a polyacetal resin and a hydrazide of a heteroatom-containing aliphatic carboxylic acid, and is excellent in extrusion and / or molding process stability and has a very small amount of formaldehyde. That is, a molded article made of a conventional polyacetal resin containing a stabilizer such as an antioxidant generates a relatively large amount of formaldehyde, and pollutes the living environment and the working environment in addition to corrosion and discoloration. For example, the amount of formaldehyde generated from a commercially available polyacetal resin molding is generally about ^{2 to 5} μg per 1 cm ^{2 of} surface area in a dry type (in a constant temperature dry atmosphere) and / or in a wet type (in a constant temperature and humid atmosphere), a surface area of 1 cm ^2. It is about 3 to 6 μg per unit.

On the other hand, the polyacetal resin molding of the present invention can effectively reduce the amount of formaldehyde generated from the molding with a smaller amount of the specific carboxylic acid hydrazide. Furthermore, when the specific carboxylic acid hydrazide and the heat-resistant stabilizer (formaldehyde inhibitor) are used in combination, the amount of formaldehyde generated can be significantly suppressed. Specifically, in the dry process, the amount of formaldehyde generated is 1.5 μg or less, preferably 0 to 1.0 μg, more preferably about 0 to 0.6 μg per 1 cm ² of the surface area of the molded product. 1.0 μg, and further about 0 to 0.1 μg can be achieved. Further, in the wet process, the amount of formaldehyde generated is 2.5 μg or less (about 0 to ² μg) per 1 cm ² of the surface area of the molded product, preferably 0 to 1.2 μg, more preferably 0 to 0.4 μg, and further preferably 0 to 0.0. About 2 μg can also be achieved, and may be usually about 0.001 to 1.2 μg.

  The molded body of the present invention only needs to have the formaldehyde generation amount in either one of the dry type and the wet type, and in particular, often has the formaldehyde generation amount in both the dry type and the wet type. . Therefore, the molded body of the present invention can also be used as a material that can cope with a more severe environment.

  The amount of formaldehyde generated in the dry method can be measured as follows.

After the polyacetal resin molded product is cut as necessary and the surface area is measured, an appropriate amount of the molded product (for example, a surface area of 10 to 50 cm ² ) is put in a sealed container (capacity 20 ml), and the temperature is 24 ° C. Leave for hours. Thereafter, 5 ml of water is injected into this sealed container, and the amount of formalin in this aqueous solution is quantified according to JIS K0102, 29 (formaldehyde term) to determine the amount of formaldehyde generated (μg / cm ² ) per surface area of the molded product.

  Moreover, the amount of formaldehyde generated in the wet state can be measured as follows.

After the polyacetal resin molded product is cut if necessary and the surface area is measured, an appropriate amount of the molded product (for example, a surface area of 10 to 100 cm ² ) is covered with a sealed container (capacity 1 L) containing 50 ml of distilled water. It is hung and sealed and left in a thermostatic bath at a temperature of 60 ° C. for 3 hours. Then, it is allowed to stand at room temperature for 1 hour, and the amount of formalin in the aqueous solution in the sealed container is quantified according to JIS K0102, 29 (formaldehyde term) to determine the amount of formaldehyde generated (μg / cm ² ) per surface area of the molded product.

  In the present invention, the numerical definition of the amount of formaldehyde generated is that of the polyacetal resin composition containing conventional additives (ordinary stabilizers, release agents, etc.) as long as the polyacetal resin and the specific carboxylic acid hydrazide are included. Not only for molded products, but also for molded products of compositions containing inorganic fillers, other polymers, etc., most of the surfaces of the molded products (for example, 50 to 100%) are formed of polyacetal resin. The present invention can also be applied to products (for example, multicolor molded products and coated molded products).

  The resin composition of the present invention can be formed into various molded products by a conventional molding method (for example, injection molding, extrusion molding, compression molding, blow molding, vacuum molding, foam molding, rotational molding, gas injection molding, etc.). Useful for molding.

  In addition, the molded article (molded article) of the present invention can be used for any application in which formaldehyde is harmful (for example, a knob, a lever, etc. as a bicycle part). Parts and passive parts), building materials / piping parts, daily necessities (life) / cosmetics parts, and medical (medical / treatment) parts.

  More specifically, automobile parts include inner handles, fael trunk openers, seat belt buckles, assist wraps, various interior parts such as switches, knobs, levers, clips, electrical system parts such as meters and connectors, audio equipment, Examples include in-vehicle electrical / electronic parts such as car navigation equipment, parts that come into contact with metal, such as window regulator carrier plates, door lock actuator parts, mirror parts, wiper motor system parts, fuel system parts, etc. it can.

  Electrical / electronic parts (mechanism parts), equipment parts or members made of polyacetal resin moldings and having many metal contacts [for example, audio equipment such as cassette tape recorders, VTRs (video tape recorders), 8mm Video equipment such as video and video cameras, or OA (office automation) equipment such as copiers, facsimiles, word processors, and computers, as well as keyboards attached to toys, telephones, computers, etc. that operate with motors, driving force, etc. Etc.]. Specifically, a chassis (base), a gear, a lever, a cam, a pulley, a bearing, etc. are mentioned. Furthermore, optical and magnetic media components (for example, metal thin film magnetic tape cassettes, magnetic disk cartridges, magneto-optical disk cartridges, etc.), at least partly composed of polyacetal resin molded products, more specifically, metal tape cassettes for music, The present invention can also be applied to a digital audio tape cassette, an 8 mm video tape cassette, a floppy (registered trademark) disk cartridge, a mini disk cartridge, and the like. Specific examples of optical and magnetic media parts include tape cassette parts (tape cassette body, reel, hub, guide, roller, stopper, lid, etc.), disk cartridge parts (disk cartridge body (case), shutter, clamping Plate).

  Furthermore, the polyacetal resin molded product of the present invention includes lighting equipment, fittings, piping, cocks, faucets, toilet peripheral parts and other building materials and piping parts, fasteners (slide fasteners, snap fasteners, hook-and-loop fasteners, rail fasteners, etc.), Suitable for a wide range of life-related parts, makeup-related parts, and medical-related parts such as stationery, lip balm / lipstick container, washer, water purifier, spray nozzle, spray container, aerosol container, general container, needle holder used.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

  In Examples and Comparative Examples, the moldability (amount of mold deposit), the amount of formaldehyde generated from dry and wet molded products, and the leachability were evaluated as follows.

[Moldability (amount of mold deposit)]
A molded product having a specific shape (diameter 20 mm × 1 mm) was continuously molded (100 shots) from a pellet formed of the polyacetal resin composition using a 30-t injection molding machine, and the degree of mold deposits was evaluated in five stages. . In addition, it means that there are few mold deposits, ie, a mold deposit is so small that a numerical value is large.

[Formaldehyde generation amount from dry molded products]
Ten test pieces (2 mm × 2 mm × 50 mm) (total surface area of about 40 cm ² ) of resin samples are put in a sealed container (capacity 20 mL), heated at a temperature of 80 ° C. for 24 hours in a thermostatic chamber, and then cooled to room temperature. Distilled water (5 mL) was injected with a syringe. The amount of formaldehyde in this aqueous solution was quantified according to JISK0102, 29 (formaldehyde term), and the amount of formaldehyde gas generated per surface area (μg / cm ² ) was calculated.

[Formaldehyde generation amount and exudation properties from wet molded products]
^Two flat test pieces (100 mm × 40 mm × 2 mm; total surface area 85.6 cm ² ) are hung on the lid of a polyethylene bottle (capacity 1 L) containing 50 ml of distilled water and sealed, and the temperature is set to 60 ° C. in a thermostatic bath. After standing for 3 hours, the mixture was allowed to stand at room temperature for 1 hour. The amount of formalin in the aqueous solution in the polyethylene bottle was quantified according to JISK0102, 29 (formaldehyde term), and the amount of formaldehyde generated per surface area (μg / cm ² ) was calculated.

Furthermore, the surface of the molded product of the flat test piece after the test was observed, and the extent of the exudate was evaluated according to the following criteria.
○: No seepage is observed Δ: Slight seepage is seen ×: Significant seepage is seen

Reference Examples 1 , 12, and 15 and Examples 2 to 11 , 13 to 14, and 16 to 22
After pre-blending carboxylic acid hydrazide, antioxidant, processing stabilizer, heat stabilizer, colorant, weathering (light) stabilizer in 100 parts by weight of polyacetal resin copolymer in the proportions shown in Tables 1 and 2, one place The mixture was melted and mixed into a main feed port of a 30 mm diameter twin-screw extruder having a vent port, and a pellet-shaped composition was prepared (extrusion conditions: L / D = 35, extrusion temperature = 200 ° C., screw rotation) Number = 100 rpm, Vent vacuum = 70 cmHg (93.1 kPa), discharge rate 15 kg / hr, average residence time = 100 seconds). Using the obtained pellets, a predetermined test piece was molded by an injection molding machine, and the moldability, the amount of formaldehyde generated from the test piece, and the bleeding property were evaluated. The results are shown in Tables 1 and 2.

Examples 23-25
A pre-blend material prepared by mixing 95 parts by weight of a polyacetal resin copolymer with an antioxidant, a processing stabilizer, a heat stabilizer, and a weather (light) stabilizer in the proportions shown in Table 2 and having a vent port at one location is 30 mm. A twin-screw extruder with a diameter is used, a pre-blend material is charged from the main feed port, melt mixed, and a blend material of 5 parts by weight of a polyacetal resin copolymer powder and a carboxylic acid hydrazide is further fed to the side feed port of the extruder. A pellet-like composition having the composition shown in Table 2 was prepared by side-feeding (extrusion conditions: L / D = 35, extrusion temperature = 200 ° C., screw rotation speed = 100 rpm, vent vacuum = 70 cmHg (93. 1 kPa), discharge rate 15 kg / hr, average residence time = 100 seconds).

  Using these pellets, a predetermined test piece was molded by an injection molding machine, and the moldability, the amount of formaldehyde generated from the test piece, and the bleeding property were evaluated. The results are shown in Table 2.

Comparative Examples 1-3
For comparison, an example in which carboxylic acid hydrazide was not added and an example in which adipic acid dihydrazide was added instead of a specific aliphatic carboxylic acid hydrazide were evaluated in the same manner as described above. The results are shown in Table 3.

  As is clear from the table, compared to the comparative example, in the example, the amount of formaldehyde generated can be reduced to a very small amount, and the working environment and the use environment can be greatly improved. Furthermore, in the examples, the leachability could be improved and the quality of the molded product could be improved.

Example 26
The method of adding the polyacetal resin pellet obtained in Example 4 to the main feed port of a 30 mm diameter twin screw extruder having one vent port and melt-mixing it again was repeated, and the total residence time was 200 seconds. (Extrusion conditions: L / D = 35, extrusion temperature = 200 ° C., screw rotation speed = 100 rpm, vent vacuum = 70 cmHg (93.1 kPa), discharge rate 15 kg / hr).

Using this pellet, a predetermined test piece was molded by an injection molding machine, and the amount of formaldehyde generated from the test piece and the exudation property were evaluated. The amount of formaldehyde generated was dry: 0.09 μg / cm ² , wet = 0.17 μg / cm ² , and the bleeding property was ◯. Moreover, when the moldability (mold deposit) was evaluated, it was 5 as a moldability evaluation standard.

Example 27
In a polyethylene bag, 0.1 part by weight of carboxylic acid hydrazide (b-1) is added to 100 parts by weight of the polyacetal resin pellet (not containing carboxylic acid hydrazide) obtained in Comparative Example 1, and blended. A pellet composition of polyacetal resin mixed with acid hydrazide was obtained. A predetermined test piece was molded by an injection molding machine using this pellet composition. When the amount of formaldehyde generated from the test piece and the exuding property were evaluated, the amount of formaldehyde generated was dry: 0.02 μg / cm ² , wet = 0.06 μg / cm ² , and the exuding property was ○. there were. Moreover, as a result of evaluating moldability (mold deposit), it was 5 of moldability evaluation criteria.

  The polyacetal resin copolymers, carboxylic acid hydrazides, antioxidants, processing stabilizers, heat stabilizers, colorants, and weather resistance (light) stabilizers used in Examples and Comparative Examples are as follows.

1. Polyacetal resin copolymer a
(A-1): Polyacetal resin copolymer (melt index = 9 g / 10 min)
(A-2): Polyacetal resin copolymer (melt index = 27 g / 10 min)
In addition, the said melt index is the value (g / 10min) calculated | required on the conditions of 190 degreeC and 2169g according to ASTM-D1238.

2. Carboxylic acid hydrazide b
(B-1): 1,3-bis (2-hydrazinocarbonylethyl) -5-isopropylhydantoin (b-2): 3,9-bis (2-hydrazinocarbonylethyl) -2,4,8, 10-tetraoxaspiro [5.5] undecane (b-3): 1- (2-hydrazinocarbonylethyl) -2-methylimidazole (b-4): 1,4-bis (2-hydrazinocarbonylethyl) ) Piperazine (b-5): bis [4- (N- (2-hydrazinocarbonylethyl) amino) phenyl] methane (b-6): 1,3-bis (2-hydrazinocarbonylethyloxy) benzene ( b-7): 2,2-bis [4- (2-hydrazinocarbonylethyloxy) phenyl] propane (b-8): 1- (2-hydrazinocarbonylethyloxy) -4- (hydrazino Carbonyl) benzene (b-9): adipic acid dihydrazide.

3. Antioxidant c
(C-1): Triethylene glycol bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate]
(C-2): Pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate]
(C-3): 2,2′-methylenebis (4-methyl-6-tert-butylphenol).

4). Processing stabilizer d
(D-1): Ethylene bisstearylamide (d-2): Montanic acid ester [Tozai Petrolite Co., Ltd., LUZAWAX-EP]
(D-3): Glycerol monostearate (d-4): Polyethylene oxide [Molecular weight: 35000]
5. Heat stabilizer (organic carboxylic acid metal salt, alkaline earth metal salt, basic nitrogen compound) e
(E-1): Tricalcium citrate tetrahydrate (e-2): Magnesium stearate (e-3): Tricalcium citrate dihydrate (e-4): Calcium stearate (e-5): Allantoin (E-6): Biurea (e-7): Nylon 6-66-610 [manufactured by DuPont, Elvamide 8063R]
6). Colorant f
(F-1): Carbon black (acetylene black)
7). Weather resistance (light) stabilizer g
(G-1): 2- [2′-hydroxy-3 ′, 5′-bis (α, α-dimethylbenzyl) phenyl] benzotriazole (g-2): bis (2,2,6,6-tetra Methyl-4-piperidyl) sebacate

Claims (14)

A polyacetal resin composition comprising a polyacetal resin, an aliphatic carboxylic acid hydrazide, an antioxidant, a heat-resistant stabilizer, and a processing stabilizer,
The aliphatic carboxylic acid hydrazide is represented by the following formula (1):
X- (R-C (= O ) -NHNH 2) n (1)
(Wherein X represents a heteroatom or an n-valent heteroatom-containing group, and the heteroatom-containing compound corresponding to this heteroatom-containing group X is an azacycloalkane, an azacycloalkene, an azacycloalkadiene, a cyclic urea, cyclic imides, Po polyhydroxy arenes, bisphenols are oxa cycloalkane, or oxa spiro alkane, R represents a linear or branched C _1-6 alkylene group, n is an integer of 1 to 4)
Represented by
The antioxidant is at least one selected from hindered phenolic compounds and hindered amine compounds,
The heat stabilizer is at least one selected from basic nitrogen compounds, phosphine compounds, organic carboxylic acids or organic carboxylic acid metal salts, alkali or alkaline earth metal compounds, hydrotalcite and zeolite, and the processing A polyacetal resin composition, wherein the stabilizer is at least one selected from long-chain fatty acids or derivatives thereof, polyoxyalkylene glycols, and silicone compounds. The resin composition according to claim 1, wherein the heteroatom-containing compound corresponding to the heteroatom-containing group X in the formula (1) is at least one selected from a cyclic ureido compound and a mono- or polyoxaspiro C _6-20 alkane. .   The resin composition according to claim 1, wherein the proportion of the aliphatic carboxylic acid hydrazide is 0.001 to 20 parts by weight with respect to 100 parts by weight of the polyacetal resin.   The resin composition according to claim 1, further comprising at least one selected from a weather resistance (light) stabilizer, an impact resistance improver, a gloss control agent, a slidability improver, a colorant and a filler.   The resin composition according to claim 1, wherein the heat-resistant stabilizer is at least one selected from an alkaline earth metal salt of an organic carboxylic acid and an alkaline earth metal oxide.   The resin composition according to claim 1, wherein the heat stabilizer is an alkaline earth metal salt of oxyacid.   Weathering (light) stabilizers include benzotriazole compounds, benzophenone compounds, aromatic benzoate compounds, cyanoacrylate compounds, oxalic acid anilide compounds, hydroxyaryl-1,3,5-triazine compounds and hindered amine compounds. The resin composition of Claim 4 comprised by at least 1 type selected from these.   The resin composition according to claim 4, wherein the impact resistance improver comprises at least one selected from a thermoplastic polyurethane resin, an acrylic core-shell polymer, a thermoplastic polyester elastomer, and a styrene elastomer.   The resin composition according to claim 4, wherein the gloss control agent is composed of at least one selected from an acrylic resin and a styrene resin.   The resin composition according to claim 4, wherein the slidability improver is composed of at least one selected from an olefin polymer, a silicone resin, and a fluorine resin.   The resin composition according to claim 1, wherein the pellet of the polyacetal resin and an aliphatic carboxylic acid hydrazide or a master batch containing the aliphatic carboxylic acid hydrazide coexist.   A method for producing a polyacetal resin composition comprising melt-mixing a polyacetal resin, an aliphatic carboxylic acid hydrazide, an antioxidant, a heat stabilizer, and a processing stabilizer using an extruder, comprising at least the aliphatic carboxylic acid The method for producing a polyacetal resin composition according to claim 1, wherein the acid hydrazide is fed from a side feed port of an extruder and mixed.   A polyacetal resin, an aliphatic carboxylic acid hydrazide, an antioxidant, a heat-resistant stabilizer, and a processing stabilizer are melt-mixed using an extruder, and a method for producing a polyacetal resin composition, the average in the extruder The method for producing a polyacetal resin composition according to claim 1, wherein the residence time is 300 seconds or less.   A molded article formed of the polyacetal resin composition according to claim 1.