JP4739814B2 - POLYACETAL RESIN COMPOSITION AND MOLDED ARTICLE - Google Patents

Description

  The present invention is a polyacetal resin composition capable of suppressing the amount of formaldehyde generated to an extremely low level, and suppressing the generation of deposits (mold deposits) on the mold during molding and bleeding out in the molded product, and the resin composition. Related to the molded product.

  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, there is a demand for polyacetal resins that are more excellent in thermal stability and generate very little formaldehyde.

  In general, formaldehyde is chemically active, and when oxidized, it becomes formic acid, which adversely affects heat resistance. When used in parts of electrical and electronic equipment, metal contact parts are corroded or discolored due to adhesion of organic compounds. Cause a defect. In addition, the amount of formaldehyde generated from the polyacetal resin molded product under a normal use condition is extremely small, but it is one of the factors that contaminate the working environment in the parts assembly process and the living environment around the use of the final product. Furthermore, the generation of a large amount of formaldehyde during molding generates paraformaldehyde on the mold surface, which causes mold deposits.

  Conventionally, in order to stabilize the chemical structure of the polyacetal resin, homopolymers are esterified by acetylation or the like at the polymer ends, and copolymers are adjacent carbons such as trioxane, cyclic ether, and cyclic formal during polymerization. A method is known in which, after copolymerization with a monomer having a bond, an unstable terminal portion is decomposed and removed to form an inactive stable terminal. However, cracking also occurs in the main chain of the polymer during heating, and the above treatment alone cannot be used to prevent it. In practice, the addition of stabilizers (antioxidants, other stabilizers, etc.) It is mandatory.

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

  US Pat. No. 3,152,101 (Patent Document 1) includes polyacetal copolymer and dicarboxylic acid dihydrazide (C3-C10 aliphatic dicarboxylic acid dihydrazide, aromatic dicarboxylic acid dihydrazide, alicyclic dicarboxylic acid dihydrazide, etc.). A composition is disclosed. This document specifically describes short-chain aliphatic carboxylic acid hydrazides.

  However, the use of short-chain aliphatic carboxylic acid hydrazides can improve the thermal stability to some extent and suppress the generation of formaldehyde, but significantly deteriorates the moldability and generates mold deposits derived from carboxylic acid hydrazide compounds. Or bleeding out of the carboxylic acid hydrazide from the molded product. Further, this document does not specifically disclose what kind of arylenedicarboxylic acid dihydrazide can improve the thermal stability of the resin composition.

  On the other hand, JP-A-10-36681 (Patent Document 2) discloses a synthetic resin and a hydrazide compound (monohydrazide compound including salicylic acid hydrazide, p-hydroxybenzoic acid hydrazide, naphthoic acid hydrazide, etc .; polyacrylic acid hydrazide). It is disclosed that a resin composition containing a polyhydrazide compound and the like having a deodorizing effect on acetaldehyde, formaldehyde and the like.

This document describes the combination of various resins and hydrazide compounds in order to deodorize the odor of cigarette smoke and the aldehyde odor from new building materials, but does not describe polyacetal resins. Furthermore, this document states that dihydrazide compounds are preferred, and in the examples adipic acid dihydrazide is used.
U.S. Pat. No. 3,152,101 (columns 1 and 3) Japanese Patent Laid-Open No. 10-36681 (Claim 1, paragraph numbers [0011] [0015] [0016] [0020] [0025])

  Accordingly, an object of the present invention is to provide a polyacetal resin composition and a molded product that can suppress the amount of formaldehyde generated to an extremely low level and can suppress mold deposits and bleed-outs derived from additives.

  Another object of the present invention is to provide a polyacetal resin composition and a molded article that can suppress the amount of formaldehyde generated to a low level and have improved physical properties such as weather resistance (light) resistance, impact resistance, and slidability. There is.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventor can not only suppress the generation amount of formaldehyde to an extremely low level, but also add a polyacetal resin and a specific monocyclic aromatic monocarboxylic acid hydrazide. The present inventors have found that mold deposits and bleed-out derived from the agent can be suppressed, and the present invention has been completed.

  That is, the polyacetal resin composition of the present invention comprises a polyacetal resin and a formula (1)

(In the formula, R ¹ represents a hydrocarbon group having 1 to 30 carbon atoms, R ² represents a hydrogen atom, an alkyl group having 1 to 30 carbon atoms or an acyl group, a is an integer of 1 to 4, and b is 0. Represents an integer of ~ 4)
It is comprised with the monocyclic aromatic monocarboxylic acid hydrazide represented by these.

The monocyclic aromatic monocarboxylic acid hydrazide (1) is an aromatic monocarboxylic acid hydrazide in formula (1) in which a is an integer of 1 to 2 and b is an integer of 0 to 2, for example, Even if R ¹ is a C _1-8 alkyl group, R ² is a hydrogen atom, a is an integer of 1 to 2, and b is an integer of 0 to 1, an aromatic monocarboxylic acid hydrazide Good. The monocyclic aromatic monocarboxylic acid hydrazide (1) is, in particular, a benzoic acid hydrazide having a C _1-8 alkyl group (3,5-diC _1-4 alkyl-4-hydroxybenzoic acid hydrazide or C _{1- 8} alkyl benzoic acid hydrazide and the like. The proportion of such monocyclic aromatic monocarboxylic acid hydrazide (1) may be, for example, about 0.001 to 20 parts by weight with respect to 100 parts by weight of the polyacetal resin.

  The polyacetal resin may be a copolymer having units composed of cyclic ether and / or cyclic formal as copolymerized units. In particular, it may be a copolymer composed of a cyclic oligomer unit of formaldehyde and a cyclic ether unit and / or a cyclic formal, and the ratio (weight ratio) of the cyclic oligomer unit to the cyclic ether unit and / or the cyclic formal unit. May be (cyclic oligomer unit) / (cyclic ether unit and / or cyclic formal unit) = 99.5 / 0.5 to 80/20.

  The polyacetal resin composition of the present invention further includes an antioxidant, a heat stabilizer, a processing stabilizer, a weather (light) stabilizer, an impact modifier, a slidability improver, a gloss control agent, a filler and a coloring agent. At least one selected from agents may be included. The antioxidant may be a hindered phenol compound and / or a hindered amine compound. The heat-resistant stabilizer is, for example, an organic carboxylic acid metal salt, an aminotriazine compound, a guanidine compound, a urea compound, an amino acid compound, an amino alcohol compound, an imide compound, an amide compound, a hydrazine compound, an alkali or alkaline earth metal compound, Hydrotalcite, zeolite, phosphine compounds, etc. may be used. The processing stabilizer may be a long chain fatty acid or a derivative thereof, polyalkylene glycol, a silicone compound, or the like. Furthermore, the weather resistance (light) stabilizer includes benzotriazole compounds, benzophenone compounds, aromatic benzoate compounds, cyanoacrylate compounds, oxalic acid anilide compounds, hydroxyphenyl-1,3,5-triazine compounds, and the like. It may be.

  The present invention also includes a molded article formed from the polyacetal resin composition. In this molded product, (1) the amount of formaldehyde generated when a molded product having a thickness of 2 mm was stored in a sealed space of saturated humidity at a temperature of 60 ° C. for 3 hours was 2 μg / g or less per unit weight of the molded product, and / or Or (2) The amount of formaldehyde generated when a molded product having a thickness of 2 mm is stored in a sealed space at a temperature of 80 ° C. for 24 hours may be 2 μg / g or less per unit weight of the molded product. The molded article is suitable for automobile parts, electrical / electronic parts, building materials / piping parts, daily / cosmetic parts, medical parts, and the like.

  In the present invention, since a specific monocyclic aromatic monocarboxylic acid hydrazide is added to the polyacetal resin, the amount of formaldehyde generated can be suppressed to an extremely low level. Furthermore, since mold deposits derived from the additives and bleed-out in the molded product can be remarkably suppressed, the moldability and the quality of the molded product can be improved. In addition, other additives (antioxidants, heat stabilizers, processing stabilizers, weather (light) stabilizers, impact resistance improvers, slidability improvers, gloss control agents, fillers, colorants, etc.) When added, generation of formaldehyde can be suppressed, and physical properties such as weather resistance (light) resistance, impact resistance, and slidability can be improved.

  The resin composition of the present invention is composed of a polyacetal resin and a monocyclic aromatic monocarboxylic acid hydrazide (1).

(Polyacetal resin)
The polyacetal resin is a high molecular compound having an oxymethylene group (—OCH ₂ —) as a main constituent unit, and is a polyacetal homopolymer or polyoxymethylene (eg, manufactured by DuPont, USA) consisting essentially only of repeating oxymethylene units. Trade name “Delrin”; manufactured by Asahi Kasei Kogyo Co., Ltd., trade name “Tenac 4010”, etc.), polyacetal copolymer containing at least one other comonomer unit in addition to oxymethylene units (for example, manufactured by Polyplastics Co., Ltd.) , Trade name "Duracon" etc.) is a typical resin. Furthermore, the polyacetal resin may be a conventional polyacetal resin, for example, a copolymer in which a branched structure or a crosslinked structure is introduced by copolymerizing a branch-forming component or a crosslinking-forming component, and further a repeating oxymethylene group. Also included are block copolymers and graft copolymers having units. These polyacetal resins can be used alone or in combination of two or more.

  In the present invention, the polyacetal resin is not particularly limited as long as it is a polyacetal resin having an oxymethylene unit, but it is particularly effective for a polyacetal copolymer that easily generates formaldehyde.

  In general, a polyacetal homopolymer is produced by polymerization of anhydrous formaldehyde or trioxane (a cyclic trimer of formaldehyde), and is usually stabilized against thermal decomposition by esterifying its terminal.

On the other hand, polyacetal copolymers generally include formaldehyde or a cyclic oligomer of formaldehyde (for example, trioxane) represented by the general formula (CH ₂ O) _n [wherein n represents an integer of 3 or more] It is produced by copolymerizing with a comonomer such as cyclic ether or cyclic formal, and is usually stabilized against thermal decomposition by removing terminal unstable parts by hydrolysis. In the present invention, such a polyacetal copolymer is particularly preferably used from the viewpoint of suppressing the generation of formaldehyde.

  Examples of the main raw material of the polyacetal copolymer include trioxane and tetraoxane, and trioxane is usually used. Trioxane is generally obtained by reacting an aqueous formaldehyde solution in the presence of an acidic catalyst and then purifying it by a method such as distillation. The trioxane used for the polymerization preferably does not substantially contain impurities such as water, methanol and formic acid.

  The comonomer includes a cyclic ether, a glycidyl ether compound, a cyclic formal, a cyclic ester (for example, β-propiolactone), a vinyl compound (for example, styrene, vinyl ether, etc.), and the like.

  Examples of the cyclic ether include ethylene oxide, propylene oxide, butylene oxide, cyclohexene oxide, epichlorohydrin, epibromohydrin, styrene oxide, oxetane, 3,3-bis (chloromethyl) oxetane, tetrahydrofuran, trioxepane, 1, 3-dioxane and the like can be mentioned.

  Examples of the glycidyl ether compound include alkyl or aryl glycidyl ethers (for example, methyl glycidyl ether, ethyl glycidyl ether, phenyl glycidyl ether, naphthyl glycidyl ether), alkylene or polyalkylene glycol diglycidyl ether (for example, ethylene glycol diglycidyl ether). , Triethylene glycol diglycidyl ether, butanediol diglycidyl ether), alkyl or aryl glycidyl alcohol, and the like.

  Examples of the cyclic formal include 1,3-dioxolane, propylene glycol formal, diethylene glycol formal, triethylene glycol formal, 1,4-butanediol formal, 1,5-pentanediol formal, 1,6-hexanediol formal, and the like. Can be mentioned.

  These comonomers can be used alone or in combination of two or more. Of these comonomers, cyclic ethers and / or cyclic formals are usually used, and in particular, cyclic ethers such as ethylene oxide, cyclic formals such as 1,3-dioxolane, 1,4-butanediol formal, diethylene glycol formal, and the like. preferable.

  The proportion of these comonomer (for example, cyclic ether and / or cyclic formal) units is, for example, 0.1 to 20% by weight, preferably 0.5 to 20% by weight, more preferably 0, based on the whole polyacetal resin. About 5 to 15% by weight (particularly 1 to 10% by weight). For example, when the copolymer is composed of a cyclic oligomer unit of formaldehyde and a cyclic ether unit and / or a cyclic formal unit, the ratio (weight ratio) between them is, for example, (cyclic oligomer unit) / (cyclic ether unit and / Or cyclic formal unit) = 99.5 / 0.5 to 80/20, preferably about 99.5 / 0.5 to 85/15.

  In general, a copolymer obtained by copolymerizing a comonomer is cationically polymerized using a cationic polymerization catalyst by adding an appropriate amount of a molecular weight modifier. Examples of the molecular weight modifier include low molecular weight acetal compounds which may have an alkoxy group (for example, methylal, methoxymethylal, dimethoxymethylal, trimethoxymethylal, oxymethylene di-n-butyl ether), alcohols (For example, methanol, ethanol, butanol, etc.), ester compounds, acid compounds, water and the like are exemplified. Of these, low molecular weight acetal compounds having an alkoxy group are preferred.

  Examples of the cationic polymerization catalyst include metal chlorides (lead tetrachloride, tin tetrachloride, titanium tetrachloride, aluminum trichloride, zinc chloride, vanadium trichloride, antimony trichloride, etc.), metal fluorides (phosphorus pentafluoride, Antimony pentafluoride, boron trifluoride, etc.), boron trifluoride coordination compounds (boron trifluoride diethyl etherate, boron trifluoride dibutyl etherate, boron trifluoride dioxanate, boron trifluoride acetate anhydride) Rate, boron trifluoride triethylamine complex, etc.), inorganic and organic acids (perchloric acid, acetyl perchlorate, t-butyl perchlorate, hydroxyacetic acid, trichloroacetic acid, trifluoroacetic acid, trifluoromethanesulfonic acid, p-toluenesulfone Acids), complex salt compounds (triethyloxonium teto Fluoroborate, triphenylmethyl hexafluoroantimonate, allyldiazonium hexafluorophosphate, allyldiazonium tetrafluoroborate, etc., alkyl metal salts (diethyl zinc, triethylaluminum, diethylaluminum chloride, etc.), polyphosphoric acid (heteropolyacid, isopolyacid, etc.) ). These catalysts can be used alone or in combination of two or more. Of these, boron trifluoride, boron trifluoride coordination compound, heteropolyacid, and trifluoromethanesulfonic acid are preferred. These catalysts can also be diluted with an organic solvent in advance.

  Although the manufacturing method of a polyacetal copolymer is not specifically limited, For example, you may use the copolymer obtained by the following method. As the polymerization apparatus, a conventional polymerization apparatus is used. In particular, a continuous polymerization apparatus with a biaxial paddle or the like is preferably used. The polymerization temperature is maintained at about 50 to 150 ° C. (preferably 65 to 135 ° C.). After completion of the polymerization, a neutralizing agent is usually added to neutralize and deactivate the catalyst. The neutralizing agent may be added to the product reaction product discharged from the polymerization apparatus after the polymerization reaction, or may be added to the reaction product in the polymerization apparatus. In particular, it is preferable to add the neutralizing agent immediately after the polymerization reaction. Although a neutralizing agent will not be specifically limited if it is a conventional catalyst deactivator, Usually, it is a basic compound. Examples of basic compounds include ammonia, amines (triethylamine, tributylamine, triethanolamine, tributanolamine, etc.), aminotriazine compounds, guanidine compounds, urea compounds, amino acid compounds, amino alcohol compounds, imide compounds, amide compounds. Hydrazine compounds, alkali metal or alkaline earth metal hydroxide salts, and the like. These neutralizing agents can be used alone or in combination of two or more. Further, the neutralizing agent may be used in the form of an aqueous solution. The copolymer thus obtained may be further subjected to washing, separation and recovery of unreacted monomers, drying, and the like, if necessary, by a conventional method.

  The melt index of the polyacetal resin is not particularly limited, but can be selected, for example, from a range of about 0.01 to 500 g / 10 minutes, preferably 0.1 to 100 g / 10 minutes, and more preferably 0.5 to 80 g / 10. Minutes (particularly 1 to 50 g / 10 minutes). In the present invention, the melt index is a value measured under conditions of 190 ° C. and 2.16 kgf (21.2 N) according to ASTM-D1238.

  The molecular weight of the polyacetal resin is not particularly limited, but is, for example, a weight average molecular weight of 5,000 to 500,000, preferably about 10,000 to 400,000.

(Monocyclic aromatic monocarboxylic acid hydrazide)
The feature of the present invention is that by adding the monocyclic aromatic monocarboxylic acid hydrazide represented by the formula (1) to the polyacetal resin, generation of formaldehyde can be remarkably suppressed, and the processing stability of the polyacetal resin is remarkably improved. It is in point to let you.

In the formula (1), the hydrocarbon group represented by R ¹ may be a hydrocarbon group having 1 to 30 carbon atoms, such as an alkyl group or a cycloalkyl group. Examples of the alkyl group include C _1-30 linear or branched alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, and t-butyl groups. Examples of the cycloalkyl group include C _3-30 cycloalkyl groups such as a cyclopentyl group and a cyclohexyl group. Of these hydrocarbon groups, C _1-8 alkyl groups such as methyl, ethyl, propyl, butyl and ethylhexyl groups, particularly C _1-4 alkyl groups such as methyl and t-butyl groups are preferred.

The number a of R ¹ is an integer of 1 to 4, preferably 1 to 3, and more preferably an integer of 1 to 2. When a is 2 or more, the groups R ¹ may be the same or different.

R ² is a hydrogen atom, a C _1-30 alkyl group, or a C _1-30 acyl group. Examples of the alkyl group include alkyl exemplified as R ¹ , and examples of the acyl group include acetyl, ethylcarbonyl, butylcarbonyl group, and the like. In the case of a plurality of these groups, they may be the same or a combination of two or more. The group -OR ² is usually a hydroxyl group (ie R ² = H), but a derivative group of a hydroxyl group [eg a C _1-4 alkoxy group such as a methoxy group (ie R ² is a methyl group etc. C _1-4 alkyl group), C _2-5 acyloxy group such as acetoxy group] and the like.

The number b of the group —OR ² is an integer of 0 to 4, preferably 0 to 3, more preferably 0 to 2 (particularly 0 or 1). In addition, when b is 2 or more, the groups —OR ² may be the same or different.

  These monocyclic aromatic monocarboxylic acid hydrazides are prepared by conventional methods for producing carboxylic acid hydrazides using carboxylic acid derivatives, such as (1) carboxylic acid esters (alkyl esters, etc.) and hydrazine (hydrazine hydrate). (2) a method of reacting a carboxylic acid halide (such as chloride) with hydrazine, (3) a method of reacting a carboxylate with hydrazine under heating, 4) A method of reacting acid amide corresponding to carboxylic acid with hydrazine under heating, and (5) a method of reacting ureido of carboxylic acid with hypohalite.

In these production methods, examples of the monocarboxylic acid constituting the carboxylic acid derivative used as an intermediate raw material include benzoic acid and alkylbenzoic acid [for example, toluic acid (o-toluic acid, m-toluic acid, p- Toluic acid), 2-ethylbenzoic acid, 3-ethylbenzoic acid, 4-ethylbenzoic acid, 4-isopropylbenzoic acid, 4-n-propylbenzoic acid, 4-t-butylbenzoic acid, 4- (2-ethylhexyl) ) C _1-8 alkylbenzoic acid such as benzoic acid; 2,3-dimethylbenzoic acid, 2,4-dimethylbenzoic acid, 2,5-dimethylbenzoic acid, 2,6-dimethylbenzoic acid, 3,4-dimethyl benzoate, di C _1-8 alkyl benzoate such as 3,5-dimethyl benzoic acid; 2,3,4-trimethyl benzoic acid, 2,3,5-trimethyl benzoic acid, 2,3,6 Rimechiru benzoic acid, 2,4,5-trimethyl benzoic acid, 2,4,6-trimethyl benzoic acid, tri C _1-8 alkyl benzoate such as 3,4,5-trimethyl benzoic acid; 2,3,4, Tetra-C _1-8 alkylbenzoic acid such as 5-tetramethylbenzoic acid; penta-C _1-8 alkylbenzoic acid such as pentamethylbenzoic acid], hydroxybenzoic acid (eg, 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, etc.) , 4-hydroxybenzoic acid, monohydroxybenzoic acid such as 2,3-dihydroxybenzoic acid; 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxy Dihydroxybenzoic acid such as benzoic acid and 3,5-dihydroxybenzoic acid; 3,4,5-trihydroxybenzoic acid, 2,3,4-trihydride Loxybenzoic acid, 2,4,5-trihydroxybenzoic acid, trihydroxybenzoic acid such as 2,4,6-trihydroxybenzoic acid, etc.), alkylsalicylic acid (for example, 3-methylsalicylic acid, 4-methylsalicylic acid, 5 -Methyl salicylic acid etc.), hydroxyalkyl benzoic acid (eg 3-hydroxy-2-methyl benzoic acid, 2-hydroxy-3,5-dimethyl benzoic acid, 3-hydroxy-4-isopropyl benzoic acid, 2-hydroxy-3 -Isopropyl-6-methylbenzoic acid, 4,6-dihydroxy-2-methylbenzoic acid, 2,6-dihydroxy-4-methylbenzoic acid, 3,5-di-t-butyl-4-hydroxybenzoic acid, 3 -Methyl-5-t-butyl-4-hydroxybenzoic acid, etc.), orthoric acid, alkylorceric acid (for example, Etc. Chiruoruserin acid), hydroxy-ol serine acids (e.g., 4-hydroxy-ol serine acid, 6-hydroxy-ol serine acid), Jibaru acid, Oliveros tall carboxylic acids, such as spheroplasts Hororu carboxylic acid. These carboxylic acids and derivatives thereof can be used alone or in combination of two or more.

Of the monocyclic aromatic monocarboxylic acid hydrazide (1) having such a structure, specifically, benzoic acid hydrazide having a C _1-8 alkyl group, particularly 3,5-di-t-butyl- 3,5-diC _1-4 alkyl-4-hydroxybenzoic acid hydrazide such as 4-hydroxybenzoic acid hydrazide and 3-methyl-5-t-butyl-4-hydroxybenzoic acid hydrazide, and toluic acid hydrazide (o- Toluic acid hydrazide, m-toluic acid hydrazide, p-toluic acid hydrazide), 4-t-butylbenzoic acid hydrazide, and 4- (2-ethylhexyl) benzoic acid hydrazide are preferable. These monocyclic aromatic monocarboxylic acids can be used alone or in combination of two or more.

  The proportion of the monocyclic aromatic monocarboxylic acid hydrazide (1) is, for example, 0.001 to 20 parts by weight, preferably 0.005 to 10 parts by weight, and more preferably 0.001 parts by weight with respect to 100 parts by weight of the polyacetal resin. It is about 01 to 5 parts by weight (particularly 0.01 to 1 part by weight). If the proportion of the carboxylic acid hydrazide is too small, it is difficult to effectively reduce the amount of formaldehyde generated, and if it is too large, the moldability and mechanical strength tend to be lowered.

  In the present invention, by using such a specific hydrazide compound, the amount of formaldehyde generated is greatly reduced, and the molding processability (inhibition of mold deposit) and the bleeding property from the molded product (inhibition of bleed out) are achieved. An excellent polyacetal resin composition can be obtained.

(Other additives)
The polyacetal resin composition of the present invention further includes an antioxidant, a heat stabilizer, a processing stabilizer, a weather resistance (light) stabilizer, an impact resistance improver, a slidability improver, a gloss control agent, a filler, Additives such as colorants may be included. These additives can be used alone or in combination of two or more.

(1) Antioxidants Antioxidants include hindered phenol compounds, hindered amine compounds, phosphorus compounds, sulfur compounds, hydroquinone compounds, quinoline compounds, and the like. These antioxidants can be used alone or in combination of two or more. Of these, hindered phenol compounds and hindered amine compounds are preferred.

Examples of the hindered phenolic compound include a monocyclic hindered phenol compound (such as 2,6-di-t-butyl-p-cresol), a polycyclic group connected with a hydrocarbon group or a group containing a sulfur atom. Hindered phenol compounds [2,2′-methylenebis (4-methyl-6-tert-butylphenol), 4,4′-methylenebis (2,6-di-tert-butylphenol), 1,1,3-tris (2 C _1-10 alkylene bis to tetrakis (t-butylphenol) such as -methyl-4-hydroxy-5-t-butylphenyl) butane; 4,4'-butylidenebis (3-methyl-6-t-butylphenol), etc. Of C _2-10 alkenylene or dienylene bis to tetrakis (t-butylphenol); 1,3,5-trimethyl-2,4,6-tris (3 , 5-di-t-butyl-4-hydroxybenzyl) benzene and other C _6-20 arylene or aralkylene bis to tetrakis (t-butylphenol) s; 4,4′-thiobis (3-methyl-6-tert-butylphenol) Bis (t-butylphenol) linked by a group having a sulfur atom, etc.], a hindered phenol compound having an ester group or an amide group [n-octadecyl-3- (4′-hydroxy-3 ′, 5 ′) T- having a C _2-10 alkylenecarbonyloxy group such as -di-t-butylphenyl) propionate, n-octadecyl-2- (4'-hydroxy-3 ', 5'-di-t-butylphenyl) propionate Butylphenol; 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxypheny ) Propionate], triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], pentaerythritol tetrakis [3- (3,5-di-t-butyl-4 Bis to tetrakis (t-butylphenol) s linked by polyol esters of fatty acids such as -hydroxyphenyl) propionate]; 3,9-bis [2- {3- (3-t-butyl-4-hydroxy-5- Bis having a heterocyclic group such as (methylphenyl) propionyloxy} -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5.5] undecane and a C _2-10 alkylenecarbonyloxy group To tetrakis (t-butylphenol); 2-t-butyl-6- (3'-t-butyl-5'-methyl-2) - hydroxybenzyl) -4-methylphenyl acrylate, 2- [1- (2-hydroxy-3,5-di -t- pentylphenyl) ethyl] -4,6-di -t- pentyl C _3, such as phenyl acrylate Phosphonic acids such as di-n-octadecyl-3,5-di-t-butyl-4-hydroxybenzyl phosphonate; t-alkylphenols having a _-10 alkenylenecarbonyloxy group (eg t-butylphenol and t-pentylphenol); Hindered phenol compounds having an ester group; N, N′-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy-dihydrocinnamamide, N, N′-ethylenebis [3- (3 5-Di-t-butyl-4-hydroxyphenyl) propionamide], N, N′-tetramethylene [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionamide], N, N′-hexamethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionamide], N, N′-ethylenebis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionamide], N, N′-hexamethylenebis [3- (3-t -Butyl-5-methyl-4-hydroxyphenyl) propionamide], N, N'-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine, N, N'- Bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionyl] hydrazine, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanur Over DOO, 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) hindered phenol compound having an amide unit, such as isocyanurates, etc.] and the like. 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 compounds include ester group-containing piperidine derivatives [4-acetoxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, 4- Aliphatic acyloxypiperidines such as acryloyloxy-2,2,6,6-tetramethylpiperidine (such as _C2-20 aliphatic acyloxy-tetramethylpiperidine); 4-benzoyloxy-2,2,6,6-tetramethyl Aromatic acyloxypiperidines such as piperidine (C _7-11 aromatic acyloxy-tetramethylpiperidine and the like); bis (2,2,6,6-tetramethyl-4-piperidyl) oxalate, bis (2,2,6,6) -Tetramethyl-4-piperidyl) malonate, bis (2,2,6,6-tetramethyl) -4-piperidyl) adipate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) adipate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1, 2,2,6,6-pentamethyl-4-piperidyl) sebacate and other aliphatic di or tricarboxylic acid-bis or tripiperidyl esters (such as C _2-20 aliphatic dicarboxylic acid-bispiperidyl esters); bis (2,2 , 6,6-tetramethyl-4-piperidyl) terephthalate, tris (2,2,6,6-tetramethyl-4-piperidyl) benzene-1,3,5-tricarboxylate, etc. Acid-bis to tetrakispiperidyl esters (such as aromatic di- or tricarboxylic acid-bis or tripiperidyl esters), Ether group-containing piperidine derivative [4-methoxy-2,2,6,6 C _1-10 alkoxy piperidine such as tetramethylpiperidine (C _1-6 alkoxy - tetramethyl piperidine); 4-cyclohexyloxy-2,2 C _5-8 cycloalkyloxy-piperidine such as 6,6-tetramethylpiperidine; aryloxypiperidines such as 4-phenoxy-2,2,6,6-tetramethylpiperidine; 4-benzyloxy-2,2, C _6-10 aryl-C _1-4 alkyloxy-piperidine such as 6,6-tetramethylpiperidine; alkylene di such as 1,2-bis (2,2,6,6-tetramethyl-4-piperidyloxy) ethane Oxybispiperidine (C _1-10 alkylenedioxy-bispiperidine and the like)], amide group-containing piperidine derivatives [4- ( Carbamoyloxypiperidine such as phenylcarbamoyloxy) -2,2,6,6-tetramethylpiperidine; bis (2,2,6,6-tetramethyl-4-piperidyl) hexamethylene-1,6-dicarbamate Carbamoyloxy-substituted alkylenedioxy-bispiperidine etc.] 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 proportion of the antioxidant is 0.001 to 5 parts by weight, preferably 0.005 to 3 parts by weight, more preferably 0.01 to 2 parts by weight (particularly 0.01 parts by weight) with respect to 100 parts by weight of the polyacetal resin. ˜1 part by weight).

(2) Heat-resistant stabilizer The heat-resistant stabilizer includes (a) an organic carboxylic acid metal salt, (b) a basic nitrogen compound (for example, aminotriazine compound, guanidine compound, urea compound, amino acid compound, amino alcohol compound, imide) Compound, amide compound, hydrazine compound, etc.), (c) alkali or alkaline earth metal compound, (d) hydrotalcite, (e) zeolite, (f) phosphine compound and the like.

(A) Organic carboxylic acid metal salt As the organic carboxylic acid metal salt, an organic carboxylic acid and a metal (an alkali metal such as Li, Na and K; an alkaline earth metal such as Mg and Ca; a transition metal such as Zn) and the like Of the salt.

The organic carboxylic acid may be either low-molecular or high-molecular, and other than the long-chain saturated or unsaturated aliphatic carboxylic acid exemplified in the section of long-chain fatty acid in the processing stabilizer described later, Less than 10 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 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 stearate, calcium stearate, 12-hydroxy magnesium stearate, calcium 12-hydroxy stearate (especially calcium citrate) Is preferred.

(B) Basic nitrogen compound Examples of the basic nitrogen compound include aminotriazine compounds, guanidine compounds, urea compounds, amino acid compounds, amino alcohol compounds, imide compounds, amide compounds, and hydrazine compounds. These basic nitrogen compounds can be used alone or in combination of two or more.

  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, glutaloganamine, adipogguanamine, pimeloganamin, suboguanamine, azeroguanamine, sebacoguanamine)], alicyclic guanamine series Compounds [monoguanamines (cyclohexanecarboguanamine, norbornenecarboguanamine, cyclohexenecarboguanamine, norbornanecarboguanamine and their functional group substituents (alkyl group, hydroxyl group, amino group, Derivatives in which 1 to 3 functional groups such as acetamino group, nitrile group, carboxyl group, alkoxycarbonyl group, carbamoyl group, alkoxy group, phenyl group, cumyl group, hydroxyphenyl group are substituted with cycloalkane residues) ], Aromatic guanamine compounds [monoguanamines (benzoguanamine and functional substituents thereof (alkyl groups, aryl groups, hydroxyl groups, amino groups, acetamino groups, nitrile groups, carboxyl groups, alkoxycarbonyl groups, carbamoyl groups, alkoxy groups) , A phenyl group, a cumyl group, a hydroxyphenyl group and other functional groups substituted with 1 to 5 phenyl residues of benzoguanamine, such as o-, m- or p-toruguanamine, o-, m- or p -Xyloganamin, o-, m- or p-phenylbenzene Zoguanamine, 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 [acetal groups 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 ring-containing guanamines (guanamine compound of JP 47-41120 JP etc.), etc. guanamine compound described in JP-2000-154181) and the like. In addition, compounds in which the alkoxymethyl group of the 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.] Is 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 urea (such as oligo or polynonamethylene urea), cyclic urea compounds [cyclic monoureides such as C _1-10 alkylene urea (ethylene Urea, crotonylidene urea, etc.), arylene urea (such as imesatin), ureido of dicarboxylic acid (such as parabanic acid, barbituric acid, isocyanuric acid, uramil), ureido of β-aldehyde acid (such as uracil, thymine, urazole), α- Ureides of oxyacids (hydantoins such as hydantoin; 5-methylhydan In such a 5-straight or branched C _1-6 alkyl - 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-dibenzylhydantoins 5,5-bis (C _6-10 aryl C _1-4 alkyl) hydantoins such as: C _1-10 alkylene-bishydantoins such as pentamethylenebishydantoin; allantoin or metal salts thereof (Al salts such as allantoin dihydroxyaluminum salts) Cyclic ureures such as uric acid, alkyl-substituted uric acid, acetylene urea (glycoluril) or derivatives thereof (such as mono to tetra (C _1-4 alkoxy C _1-4 alkyl) glycoluril), clothylidene diurea, Examples include α-oxyacid diureides (such as 1,1, -methylenebis (5,5-dimethylhydantoin)), diureas such as p-urazine, and dicarboxylic acid diureides (such as alloxanthin and purpuric acid).

  As amino acid compounds, α-amino acids [monoaminomonocarboxylic 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, hexahi Examples thereof include dolocincomeronic acid and the like, γ-amino acids (such as γ-aminobutyric acid), and δ-amino acids (such as δ-amino-n-valeric acid). The amino acid compound 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, Also included are esterified (methyl ester, ethyl ester, etc.) amino acid derivatives.

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 (malonamide, adipic acid amide, sebacic acid amide, dodecanoic acid amide, etc.), cyclic carboxylic acid amides (ε-caprolactam, etc.), aromatic carboxylic acid amides (benzoic acid amide, o-, m- or p-aminobenzamide, isophthalic acid diamide, terephthalic acid amide, etc.), polyamide resins [for example, polyamide 3 (poly β-alanine), polyamide 46, polyamide 6, polyamide 66, polyamide 11, polyamide 12 , Polyamide MXD6, polyamide 6-10, polyamide 6-11, polyamide 6-12, polyamide 6-66-610, polyamide 9T, etc.], polyesteramide, polyamideimide, polyurethane, poly (meth) which may be a crosslinked product Acrylic acid amide alone Or copolymers [polymers described in US Pat. No. 5,011,890], poly (vinyl lactam) homo- or copolymers [poly (N-vinyl pyrrolidone) homo- or copolymers, etc.] A homopolymer or a copolymer described in JP-A-55-52338 and US Pat. No. 3,204,014), poly (N-vinylcarboxylic acid amide), a copolymer of N-vinylcarboxylic acid amide and another vinyl monomer (For example, JP 2001-247745 A, JP 2001-131386 A, JP 8-311302 A, JP 59-86614 A, US Pat. No. 5,455,042, US Pat. No. 5,407,996, And the like described in US Pat. No. 5,338,815).

  Hydrazine compounds include aliphatic or alicyclic carboxylic acid hydrazides (saturated or unsaturated fatty acid hydrazides such as lauric acid hydrazide, stearic acid hydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, sorbic acid hydrazide, α- Oxy fatty acid hydrazide such as oxybutyric acid hydrazide and glyceric acid hydrazide), aromatic polycarboxylic acid hydrazide (phthalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide and the like).

(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 [Minimum 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 Examples of the phosphine compound include alkyl phosphines (for example, tri-C _1-10 alkyl phosphines such as triethyl phosphine, tripropyl phosphine, and tributyl phosphine) and cycloalkyl phosphines (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 phosphide Etc.), 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, Mono or di C _6-12 aryl-di or mono C _2-10 alkenyl phosphine), aryl aralkyl phosphine (eg, p-anisyl diphenyl phosphine, di (p-anisyl) phenyl phosphine, etc. Or a di C _6-12 aryl-di or mono (C _6-12 aryl C _1-4 alkyl) phosphine; and a substituent such as a C _1-10 alkyl group such as methylphenyl-p-anisylphosphine which may C _6-12 aryl - such as (C _6-12 aryl C _1-4 alkyl) phosphine), bis phosphines For example, 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. The ratio of the heat stabilizer is, for example, about 0.001 to 10 parts by weight, preferably about 0.001 to 5 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.

(3) Processing stabilizer The processing stabilizer includes (a) a long-chain fatty acid or a derivative thereof, (b) a polyalkylene glycol, (c) a silicone compound, and the like. These processing stabilizers can be used alone or in combination of two or more.

(A) Long chain fatty acid or derivative thereof The long chain fatty acid may be a saturated fatty acid or an unsaturated fatty acid. Moreover, the fatty acid by which one part hydrogen atom was substituted by substituents, such as a hydroxyl group, can also 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 polyalkylene glycol is 2 or more (for example, 2 to 500), preferably about 2 to 400 (for example, 2 to 360), more preferably an average degree of polymerization of 16 or more (for example, about 20 to 200). ). When polyalkylene 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, for example, a monovalent C _12-26 saturated or unsaturated fatty acid, and a divalent C _It is preferable to use _12-20 saturated or unsaturated fatty acids. 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) Polyalkylene glycol Polyalkylene glycol includes alkylene glycol [for example, C _2-6 alkylene glycol (preferably C _2-4 alkylene glycol) such as ethylene glycol, propylene glycol, tetramethylene glycol, etc.]. Polymers and their derivatives are included.

Specific examples of the polyalkylene glycol include poly C _2-6 alkylene glycol (preferably poly C _2-4 alkylene glycol) such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polyoxyethylene-polyoxypropylene copolymer. (Random or block copolymer, etc.), 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 polyalkylene 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 ^3). About 5 × 10 ⁴ ). Polyalkylene glycol can be used individually or in combination of 2 or more types.

(C) Silicone compound The silicone compound includes (poly) organosiloxane. (Poly) organosiloxane includes monoalkylsiloxanes such as dialkylsiloxanes (for example, dimethylsiloxane), alkylarylsiloxanes (for example, phenylmethylsiloxane), diarylsiloxanes (for example, 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.

(4) Weather resistance (light) stabilizer As the weather resistance (light) stabilizer, (a) benzotriazole compound, (b) benzophenone compound, (c) aromatic benzoate compound, (d) cyanoacrylate compound, (E) Oxalic acid anilide compounds, (f) hydroxyaryl-1,3,5-triazine compounds, (g) hindered amine compounds, and the like. These weather resistance (light) stabilizers can be used alone or in combination of two or more.

(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 (2'-hydroxy-4'-octoxyphenyl) hydroxyl group and alkoxy (C _1-12 alkoxy), such as benzotriazole benzotriazoles having a substituted aryl group group.

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 the 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-hydride Carboxymethyl-4 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 and ethyl-2-cyano-3,3-diphenyl acrylate ( In particular, cyano group-containing diphenyl acrylate and the like).

(E) Oxanilic 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 Diphenyl-6- (2-hydroxy - alkoxyphenyl) 2,4 corresponding to 1,3,5-triazine (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-to And hydroxyalkoxyalkoxyaryltriazines such as yl-6- (2-hydroxy-4- (2-hexyloxyethoxy) phenyl) -1,3,5-triazine.

(G) Hindered amine compound As the hindered amine compound, the hindered amine compound 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 particular, it is preferable to use a benzotriazole compound and a hindered amine compound in combination, and the ratio (weight ratio) of both is benzotriazole compound / hindered amine compound = 100/0 to 20/80, preferably 90/10 to 10, It may be about 30/70, more preferably about 80/20 to 40/60.

  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 to 4 parts by weight (for example, 0.1 parts by weight) with respect to 100 parts by weight of the polyacetal resin. 1 to 4 parts by weight), more preferably about 0 to 2 parts by weight (for example, 0.1 to 2 parts by weight).

(5) Impact resistance improver Examples of impact resistance improvers include thermoplastic polyurethane resins, acrylic core-shell polymers, thermoplastic polyester elastomers, styrene elastomers, olefin elastomers, polyamide elastomers, rubber components ( Natural rubber). These impact modifiers can be used alone or in combination of two or more. Of these impact resistance improvers, thermoplastic polyurethane resins, acrylic core-shell polymers, thermoplastic polyester elastomers, styrene elastomers, and the like are widely used.

  The ratio of the impact modifier is, for example, 0 to 50 parts by weight (for example, 0.1 to 50 parts by weight), preferably 1 to 30 parts by weight, more preferably 100 parts by weight of the polyacetal resin. About 3 to 20 parts by weight.

(6) Sliding property improving agent Examples of the sliding property improving agent include olefin polymers (for example, poly C _2-4 olefin resins such as polyethylene and polypropylene) and waxes (for example, olefins such as polyethylene wax). And waxes), silicone resins (for example, silicone compounds exemplified in the section of the processing stabilizer), fluorine resins (for example, polytetrafluoroethylene) and the like. These slidability improvers can be used alone or in combination of two or more. Of these slidability improvers, olefin polymers such as polyethylene, silicone resins, fluorine resins, and the like are widely used.

  The ratio of the slidability improver is, for example, 0 to 30 parts by weight (for example, 0.01 to 20 parts by weight), preferably 0.1 to 20 parts by weight with respect to 100 parts by weight of the polyacetal resin. Preferably it is about 0.5-10 weight part.

(7) Gloss Control Agent As the gloss control agent, in addition to a transparent resin, for example, the resin exemplified in the section of impact modifier, a C _1-6 alkyl (meth) acrylate homopolymer or copolymer (for example, , Polymethyl methacrylate, etc.), polycarbonate resins (for example, bisphenol resins such as bisphenol A type phenol resins), styrene resins (for example, polystyrene, AS resins, AES resins, etc.), olefin resins (for example, polypropylene or Cyclic polyolefin, etc.). These gloss control agents can be used alone or in combination of two or more. Of these gloss control agents, homo- or copolymers (for example, polymethyl methacrylate) having methyl methacrylate units are widely used.

  The ratio of the gloss control agent is, for example, 0 to 30 parts by weight (for example, 0.01 to 20 parts by weight), preferably 0.1 to 20 parts by weight, more preferably 100 parts by weight of the polyacetal resin. About 0.5 to 10 parts by weight.

(8) Filler Examples of the filler include various polymers (for example, acrylic resins, polycarbonate resins, polyolefin resins, polyolefin elastomers, polyvinyl alcohol resins, aliphatic polyester resins, etc.), fibrous fillers. [For example, inorganic fiber (for example, glass fiber, carbon fiber, boron fiber, potassium titanate fiber (whisker), etc.), organic fiber (for example, amide fiber, etc.), etc.], plate-like filler (for example, glass flake, mica, etc.) , Graphite, various metal foils, etc.), granular fillers [for example, metal oxides (zinc oxide, alumina, etc.), sulfates (calcium sulfate, magnesium sulfate, etc.), carbonates (calcium carbonate, etc.), glasses (mild Fiber, glass beads, glass balloons, etc.), silicates (talc, Orin, silica, diatomaceous earth, clay, wollastonite, etc.), sulfides (molybdenum disulfide, tungsten disulfide, etc.), carbides (fluorinated graphite, silicon carbide, etc.), boron nitride, etc.]. These fillers can be used alone or in combination of two or more. Of these fillers, fibrous fillers such as glass fibers and carbon fibers, plate-like fillers such as glass flakes and mica, and particulate fillers such as talc and silica are widely used.

  The proportion of the filler is, for example, 0 to 150 parts by weight (for example, 1 to 150 parts by weight), preferably 3 to 100 parts by weight, and more preferably 5 to 50 parts by weight with respect to 100 parts by weight of the polyacetal resin. Degree.

(9) Colorant 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.

  These colorants can be used alone or in combination of two or more. Among these, when a colorant (carbon black, titanium white (titanium oxide), phthalocyanine pigment, perylene pigment (particularly carbon black, perylene black pigment), etc.) having a high light shielding effect is used, weather resistance (light) Can be improved.

  The ratio of the colorant 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 0.1 to 100 parts by weight of the polyacetal resin. About 2 parts by weight.

  If necessary, the polyacetal resin composition of the present invention may contain other conventional additives such as mold release agents, nucleating agents, antistatic agents, flame retardants, foaming agents, surfactants, antibacterial agents, antifungal agents. Agents, fragrances, fragrances, and the like may be included. These other additives can also be used alone or in combination of two or more.

(Production method of polyacetal resin composition)
The polyacetal resin composition of the present invention may be a granular mixture or a molten mixture, and includes a polyacetal resin, a monocyclic aromatic monocarboxylic acid hydrazide (1), and, if necessary, other additives [antioxidants, Heat resistance stabilizer, processing stabilizer, weather resistance (light) stabilizer, impact resistance improver, slidability improver, gloss control agent, filler, colorant, etc.] can be prepared by a conventional method. . 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 then (2) the monocyclic Components containing no aromatic monocarboxylic acid hydrazide (polyacetal resin, other additives, etc.) from the main feed port, and components containing at least the monocyclic aromatic monocarboxylic acid hydrazide (as other components, polyacetal resin, The above-mentioned other additives, etc.) are fed from a side feed port, kneaded and extruded by an extruder to prepare pellets, and then molded, (3) including a part of the monocyclic aromatic monocarboxylic acid hydrazide Ingredients (as other ingredients, polyacetal resin, other additives, etc.) from the main feed port and the remaining monocyclic aromatic monocarboxylic acid hydrazine (4) Pellets having different compositions (4) once the composition containing the components (polyacetal resin, other additives, etc. as the other components) are fed from the side feed port and kneaded and extruded by an extruder to prepare pellets (4) A master batch), and a pellet is mixed (diluted) with a predetermined amount and subjected to molding to obtain a molded product with a predetermined composition. (5) The monocyclic aromatic monocarboxylic acid hydrazide is formed into a pellet of polyacetal resin. For example, a method of forming a molded product having a predetermined composition after molding may be applied by coexisting or adhering by spraying, coating (surface coating, etc.) or the like.

  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. The melt mixing temperature is not lower than the melting point of the resin, usually about 170 to 270 ° C., preferably about 180 to 250 ° C. In addition, the side feed of the monocyclic aromatic monocarboxylic acid hydrazide is possible from any of the feed ports before and after the devolatilization vent port, but the method of feeding after the devolatilization vent port is particularly preferable. . 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 the preparation of the composition used for the molded article, the polyacetal resin powder (for example, a powder obtained by pulverizing part or all of the polyacetal resin) and other components (the monocyclic aromatic) When the monocarboxylic acid hydrazide (1) and other additives are mixed and melt-kneaded, it is advantageous to improve dispersion of the additives.

  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, it is possible to remarkably suppress adhesion of decomposition products and additives to the mold (mold deposit) and leaching of decomposition products and additives from the molded product (bleed out).

(Molding)
The molded product formed with the said resin composition is also contained in this invention. The molded article contains a combination of a polyacetal resin and a monocyclic aromatic monocarboxylic acid hydrazide (1), is excellent in extrusion and / or molding process stability, and generates very little formaldehyde. In other words, a molded article made of a conventional polyacetal resin generates a relatively large amount of formaldehyde, contaminates the living environment and the working environment in addition to corrosion and discoloration, and is likely to generate mold deposits.

  In contrast, the polyacetal resin molded product of the present invention can greatly suppress the generation of formaldehyde. Specifically, in the wet process, the amount of formaldehyde generated is 2 μg / g or less (about 0 to 2 μg / g) per unit weight of the molded product, preferably 0 to 1 μg / g, more preferably about 0 to 0.3 μg / g. Can also be achieved. In the dry process, the amount of formaldehyde generated can be 2 μg / g or less (0 to 2 μg / g), preferably 0 to 1 μg / g, more preferably about 0 to 0.3 μg / g per unit weight of the molded product. is there.

  The molded product of the present invention may have the formaldehyde generation amount in either one of the wet type and the dry type, and in particular, in many cases both the wet type and the dry type have the formaldehyde generation amount. . The molded article of the present invention can also be used as a material that can cope with a more severe environment.

  In addition, the amount of formaldehyde generated by wet can be measured as follows. A polyacetal resin molded product (thickness 2 mm) is hung from the lid of a sealed container (capacity 1 L) containing 50 ml of distilled water, sealed, and left in a constant temperature 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 formaldehyde 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 / g) per unit weight of the molded product.

  On the other hand, the amount of formaldehyde generated in the dry process can be measured as follows. A polyacetal resin molded product (thickness 2 mm) is placed in a sealed container (capacity 20 ml) and left at a temperature of 80 ° C. for 24 hours. Thereafter, 5 ml of water is poured into this sealed container, and the amount of formaldehyde in this aqueous solution is determined according to JIS K0102, 29 (formaldehyde term) to determine the amount of formaldehyde generated (μg / g) per unit weight of the molded product. In addition, the resin molded product is prepared in a normal state (20 ° C., about 65% RH) in a stage before being placed in the sealed container.

  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 (mechanical parts), such as equipment parts or members made of polyacetal resin molding and having many metal contacts [for example, audio equipment such as cassette tape recorders, audio equipment such as CD / DVD players, etc. , VTR (video tape recorder), video equipment such as 8mm video camera, digital video camera, etc., or OA (office automation) equipment such as copier, facsimile, word processor, computer, etc. Furthermore, it operates with driving force such as motor, sag Toys, telephones, keyboards attached to computers, etc.]. Specific examples of these parts or members include a chassis (base), a gear, a lever, a cam, a pulley, and a bearing. 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 digital video cassette, a floppy (registered trademark) disk cartridge, a mini disk cartridge, a DVD 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 amount of formaldehyde generated from the molded product, the moldability (mold deposit), and the bleeding property (bleed out) from the molded product were evaluated as follows.

[Formaldehyde generation from wet molded products]
Two flat test pieces (100 mm × 40 mm × 2 mm, molding temperature 190 ° C.) are hung from a polyethylene bottle (capacity 1 L) containing 50 ml of distilled water, sealed, and sealed in a thermostatic bath at a temperature of 60 ° C. 3 After standing for a period of time, the mixture was allowed to stand at room temperature for 1 hour. The amount of formaldehyde in the aqueous solution in the polyethylene bottle was quantified according to JISK0102, 29 (formaldehyde term), and the amount of formaldehyde generated per unit weight (μg / g) was calculated.

[Formaldehyde generation amount from dry molded products]
Ten prismatic test pieces (2 mm × 2 mm × 50 mm, molding temperature 190 ° C.) are put in a sealed container (capacity 20 ml), heated at a temperature of 80 ° C. for 24 hours in a constant temperature premises, then air-cooled to room temperature, and 5 ml of distilled water. 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 generated per unit weight (μg / g) was calculated.

[Moldability (mold deposit)]
A disk-shaped molded product (molding temperature 200 ° C., diameter 20 mm × 1 mm) is continuously molded (100 shots) using a 30-t injection molding machine from pellets formed from the polyacetal resin composition, and a mold deposit (mold) The degree of deposit was evaluated according to the following criteria.

○: No mold deposit is observed Δ: Slight mold deposit is observed ×: Significant mold deposit is observed

[Bleed out from molded products]
In a formaldehyde generation test from a wet molded product, the surface of the molded product of the flat test piece after the test was visually observed, and the extent of the exudate (bleed out) was evaluated according to the following criteria.

○: No bleed-out is observed at all Δ: Slight bleed-out is observed ×: Remarkable bleed-out is observed

Examples 1-25
A ratio of monocyclic aromatic monocarboxylic acid hydrazide, antioxidant, heat stabilizer, processing stabilizer, weathering (light) stabilizer, and other additives in 100 parts by weight of polyacetal resin copolymer shown in Tables 1 to 3 After being pre-blended, the mixture was introduced into the main feed port of a 30 mm diameter twin screw extruder having one vent port and melted and mixed at 200 ° C. to prepare a pellet-shaped composition. Using the obtained pellets, predetermined test pieces were molded by an injection molding machine, and the amount of formaldehyde generated from the test pieces, mold deposit, and bleed out were evaluated. The results are shown in Tables 1-3.

Comparative Examples 1-17
For comparison, an example in which no monocyclic aromatic monocarboxylic acid hydrazide compound was added and an example in which another carboxylic acid hydrazide (adipic acid dihydrazide) was added were evaluated in the same manner as described above. The results are shown in Tables 1-3.

  The polyacetal resin copolymers, carboxylic acid hydrazide compounds, antioxidants, heat stabilizers, processing stabilizers, weathering (light) stabilizers and other additives used in Examples and Comparative Examples are as follows.

1. Polyacetal copolymer a
(A-1): Polyacetal resin copolymer (copolymer of trioxane and 1,3-dioxolane, 3.8% by weight copolymerization of 1,3-dioxolane, melt index = 9 g / 10 min)
(A-2): Polyacetal resin copolymer (copolymer of trioxane and 1,3-dioxolane, 3.6% by weight copolymerization of 1,3-dioxolane, melt index = 27 g / 10 min)
The melt index is a value determined under conditions of a temperature of 190 ° C. and a load of 2.16 kgf (21.2 N) according to ASTM-D1238.

2. Carboxylic acid hydrazide b
(Monocyclic aromatic monocarboxylic acid hydrazide)
(B-1): 3,5-di-t-butyl-4-hydroxybenzoic acid hydrazide (b-2): 3-methyl-5-t-butyl-4-hydroxybenzoic acid hydrazide (b-3): p-Toluic acid hydrazide (b-4): 4-t-butylbenzoic acid hydrazide (other carboxylic acid hydrazides)
(B-5): Adipic acid dihydrazide (b-6): Benzoic acid hydrazide.

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].

4). Heat stabilizer d
(D-1): calcium stearate (d-2): calcium citrate (d-3): 12-hydroxycalcium stearate (d-4): magnesium oxide.

5. Processing stabilizer e
(E-1) Ethylene bisstearylamide (e-2): Montanic acid ester [Tozai Petrolite Co., Ltd., LUZA WAX-EP]
(E-3): Polyethylene oxide [molecular weight: 35000].

6). Weather resistance (light) stabilizer f
(F-1): 2- [2′-hydroxy-3 ′, 5′-bis (α, α-dimethylbenzyl) phenyl] benzotriazole (f-2): bis (1,2,2,6,6) -Pentamethyl-4-piperidyl) sebacate.

7). Other additives g
(G-1) Acrylic core-shell polymer [Takeda Pharmaceutical Co., Ltd., Staphyloid PO]
(G-2) Thermoplastic polyurethane [manufactured by Nippon Milactron Co., Ltd., Milactolan E]
(G-3): Carbon black (acetylene black)
(G-4): Glass fiber (a chopped strand having a diameter of 9 μm and a length of 3 mm).

  As is apparent from the table, the resin composition of the example has an extremely small amount of formaldehyde generated as compared with the comparative example. Furthermore, it is possible to improve the moldability by suppressing the occurrence of mold deposits, and to prevent the seepage and improve the quality of the molded product.

Claims (16)

Polyacetal resin and formula (1)
(In the formula, R ¹ represents a hydrocarbon group having 1 to 30 carbon atoms, R ² represents a hydrogen atom, an alkyl group having 1 to 30 carbon atoms or an acyl group, a is an integer of 1 to 4, and b is 0. Represents an integer of ~ 4)
The polyacetal resin composition comprised by the monocyclic aromatic monocarboxylic hydrazide represented by these.   The resin composition according to claim 1, wherein in formula (1), a is an integer of 1 to 2 and b is an integer of 0 to 2. The formula (1), wherein R ¹ is a C _1-8 alkyl group, R ² is a hydrogen atom, a is an integer of 1 to 2, and b is an integer of 0 to 1. Resin composition. The resin composition according to claim 1, wherein the monocyclic aromatic monocarboxylic acid hydrazide (1) is a benzoic acid hydrazide having a C _1-8 alkyl group. The monocyclic aromatic monocarboxylic acid hydrazide (1) is at least one selected from 3,5-diC _1-4 alkyl-4-hydroxybenzoic acid hydrazide and C _1-8 alkylbenzoic acid hydrazide. 1. The resin composition according to 1.   The resin composition according to claim 1, wherein the ratio of the monocyclic aromatic monocarboxylic acid hydrazide (1) is 0.001 to 20 parts by weight with respect to 100 parts by weight of the polyacetal resin.   2. The resin composition according to claim 1, wherein the polyacetal resin is a copolymer having at least one unit selected from cyclic ether and cyclic formal as copolymerized units.   The polyacetal resin is a copolymer composed of a cyclic oligomer unit of formaldehyde, a cyclic ether unit and / or a cyclic formal unit, and the ratio (weight ratio) of the cyclic oligomer unit to the cyclic ether unit and / or the cyclic formal unit. ) Is (cyclic oligomer unit) / (cyclic ether unit and / or cyclic formal unit) = 99.5 / 0.5 to 80/20.   Furthermore, it contains at least one selected from an antioxidant, a heat stabilizer, a processing stabilizer, a weather resistance (light) stabilizer, an impact resistance improver, a slidability improver, a gloss control agent, a filler, and a colorant. The resin composition according to claim 1.   The resin composition according to claim 9, wherein the antioxidant contains at least one selected from a hindered phenolic compound and a hindered amine compound.   Heat stabilizer is organic carboxylic acid metal salt, aminotriazine compound, guanidine compound, urea compound, amino acid compound, amino alcohol compound, imide compound, amide compound, hydrazine compound, alkali or alkaline earth metal compound, hydrotalcite, zeolite And at least one selected from phosphine compounds.   The resin composition according to claim 9, wherein the processing stabilizer contains at least one selected from a long-chain fatty acid or a derivative thereof, a polyalkylene glycol, and a silicone compound.   The weathering (light) stabilizer was selected from benzotriazole compounds, benzophenone compounds, aromatic benzoate compounds, cyanoacrylate compounds, oxalic acid anilide compounds and hydroxyphenyl-1,3,5-triazine compounds. The resin composition of Claim 9 containing at least 1 type.   A molded article formed of the polyacetal resin composition according to claim 1.   (1) The amount of formaldehyde generated when a molded article having a thickness of 2 mm is stored for 3 hours in a sealed space of saturated humidity at a temperature of 60 ° C. is 2 μg / g or less per unit weight of the molded article, and / or (2) temperature. The molded product according to claim 14, wherein the amount of formaldehyde generated when a molded product having a thickness of 2 mm is stored in a sealed space at 80 ° C for 24 hours is 2 µg / g or less per unit weight of the molded product.   15. The molded article according to claim 14, which is an automobile part, an electric / electronic part, a building material / piping part, a daily / cosmetic part or a medical part.