JP6473067B2 - Composite parts, polyoxymethylene resin parts, and resin compositions - Google Patents

Description

  The present invention relates to a composite part, a polyoxymethylene resin part, and a resin composition.

Resins have advantages such as low specific gravity compared to metals, no rust, and excellent workability. On the other hand, metals such as iron and alloys have advantages such as stable mechanical strength and rigidity in a wide temperature range, and excellent electrical conductivity and electromagnetic shielding properties.
Taking advantage of these resins and metals, composite parts composed of metal parts and resin parts are used in a wide range of applications, mainly electric equipment, electrical equipment parts, automobile parts and other industrial parts.

Examples of composite parts composed of metal parts and resin parts include cases (metal devices, wiring boards and resin containers, etc.), tanks (metal gauges, pumps, resin containers, etc.), cartridges (metal Springs and shafts and resin casings and rollers), lights (metal lamps and resin covers, etc.), rollers (metal shafts and resin rollers, etc.), belts (metal rollers and resin belts, etc.) Etc.), gears (metal covers and resin gears, etc.), valves and pipes (metal pipes and resin joints, etc.), meters (metal cases and resin measuring parts, etc.) and cords (metal Wiring and a resin coating portion).
On the other hand, these composite parts have excellent durability when used in a normal atmosphere, but when used for a long time in a high-temperature and high-humidity environment, the deterioration of the resin progresses or metal Deterioration or deformation may occur and the performance may deteriorate.

Conventionally, various proposals regarding the characteristics of composite parts have been made in order to improve durability in use in a high temperature and high humidity environment.
Patent Document 1 discloses a technique of adding a polymer containing a functional group that reacts with a terminal group of a biodegradable resin and a methacrylic acid ester copolymer in the biodegradable resin.
Patent Document 2 discloses a technique of blending a metal powder having a standard unipolar potential lower than that of a metal of a metal partner material into a resin sliding material which is in sliding contact with the metal partner material and is mainly composed of polytetrafluoroethylene resin. ing.
Patent Document 3 discloses that in a polyester elastomer resin composition, a specific polyetherester block copolymer, an ethylene copolymer having a carboxylic acid metal base in a side chain and / or an alkali metal salt of carboxylic acid and / or A technique for blending an alkali metal salt of an organic phosphate compound is disclosed.
Patent Document 4 discloses a technique of adding an inorganic powder that is a solid solution of specific magnesium oxide and aluminum oxide to a polyoxymethylene resin.

JP 2007-291171 A JP 2008-63488 A JP 2005-187732 A JP-A-8-302155

However, the techniques disclosed in Patent Documents 1 to 4 still have room for improvement when used in a high temperature and high humidity environment. For example, when used in a high-temperature and high-humidity environment, there are problems that the appearance may be deteriorated and smooth operability may not be obtained.
Accordingly, an object of the present invention is to provide a composite part that retains its appearance and has excellent durability operability when used in a high temperature and high humidity environment.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have solved the above-mentioned problems by forming a composite part having specific characteristics in a composite part including a metal part and a polyoxymethylene resin part. The present invention has been completed by finding out what can be done.

That is, the present invention is as follows.
[1]
Metal parts polyoxymethylene resin component A including composite part,
The amount of acetic acid extracted into the water of the beaker after being put in a sealed 2 L polypropylene container together with a beaker containing 150 g of water and left in an oven at a temperature of 80 ° C. for 15 days and then returned to room temperature is The composite part which is 100 mass ppm or less with respect to the mass of the resin parts made from polyoxymethylene.
[2]
Amount of total organic carbon extracted into beaker water after being placed in a sealed 2L polypropylene container with a beaker containing 150 g of water, left in an oven at a temperature of 80 ° C. for 15 days, and then returned to room temperature. The composite part according to [1], in which is 500 ppm by mass or less based on the mass of the polyoxymethylene resin part.
[3]
The composite part according to [1] or [2], wherein the metal part is a steel-based metal.
[4]
[1] to [3], wherein the polyoxymethylene resin parts and / or the metal parts are used by being operated, or the metal parts are used by being energized.
] The composite part as described in any one of.
[5]
A polyoxymethylene resin part included in the composite part according to any one of [1] to [4], wherein the polyoxymethylene resin part has a sliding portion with the metal part.
[6]
A resin composition contained in a polyoxymethylene resin part included in the composite part according to any one of [1] to [4],
A resin composition having a melt flow rate (MFR) of 0.9 to 45 g / 10 min and containing a stabilizer.

  ADVANTAGE OF THE INVENTION According to this invention, the composite component which has the durable operability while maintaining an external appearance can be obtained in use in a high-temperature, high-humidity environment.

The schematic perspective view of an example of the composite component of this embodiment is shown. The schematic perspective view of another example of the composite component of this embodiment is shown. The schematic perspective view of another example of the composite component of this embodiment is shown. The schematic perspective view of another example of the composite component of this embodiment is shown. The schematic plan view of an example of the metal component used in the Example is shown. The schematic plan view of an example of the resin component made from polyoxymethylene used in the Example is shown. The schematic of the state when adjusting a composite component under the high temperature high humidity used in the Example is shown. The schematic of the state which performs durable operability evaluation used in the Example is shown. (A) The schematic perspective view of the bottom part of the container made from SUS304 used in the Example is shown. (B) The schematic perspective view of the cover part of the container made from SUS304 used in the Example is shown. (C) The schematic perspective view of the state which made the bottom part and cover part of the container made from SUS304 used in the Example match is shown. The schematic of the state which accommodated the metal component and the resin component made from an oxymethylene resin in the SUS304 container used in the Example is shown. The schematic diagram of the state which accommodates a metal component and the resin component made from an oxymethylene resin in the SUS304 container used in the Example, and adjusts a composite component under high temperature and high humidity is shown.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described. The present invention is not limited to the following embodiments, and can be implemented with various modifications within the scope of the gist.

[Composite parts]
The composite part of this embodiment is a composite part including a metal part and a polyoxymethylene resin part, and the amount of acetic acid extracted into 150 g of water coexisting in an environment left at 80 ° C. for 15 days is It is a composite part of 100 mass ppm or less with respect to the mass of the methylene resin part.

(Metal parts (M))
The composite part of this embodiment includes a metal part (M), and the metal part (M) is made of metal (m).
<(1) Metal (m)>
Examples of the metal (m) include, but are not limited to, steel-based metals (carbon steel, alloy steel, cast iron, etc.) and non-ferrous metals (magnesium, aluminum, zinc, nickel, noble metals, low melting point) Metal and their alloys).
As the metal (m), when it is a composite part processed into a movable part, a structural material, a container, etc., a steel-based metal is used from the viewpoint of maintaining the appearance in use in a high-temperature and high-humidity environment and having excellent durability operability. Preferably used.

<(2) Manufacturing method of metal part (M)>
The manufacturing method of the metal part (M) can be used regardless of any known manufacturing method or processing method, and is not particularly limited. The metal part (M) after manufacture and processing is preferably manufactured so as to have a smooth surface property with few burrs.
The manufacturing method and processing method of the metal part (M) are not limited to the following, but include, for example, casting (sand mold, mold, die casting, precision casting, etc.), plastic processing (rolling, drawing, extrusion, and the like) Punching, etc.) and cutting out. In order to increase the surface hardness, quenching, tempering, forging and the like may be performed. In addition, plating, painting, surface coating treatment, and the like may be performed in order to maintain and improve design properties.
In order to develop functionality, several parts may be combined to form a metal part (M).

(Polyoxymethylene resin parts (P))
The composite part of the present embodiment includes a polyoxymethylene resin part (P), and the polyoxymethylene resin part (P) is composed of a resin composition (p).
The polyoxymethylene resin part (P) may be combined with several parts in order to develop desired functionality.
The polyoxymethylene resin part (P) preferably has a sliding part with the metal part (M) because the composite part of the present embodiment is excellent in durability operation under high temperature and high humidity.

<Resin composition (p)>
The resin composition (p) contains polyoxymethylene (A). Moreover, the resin composition (p) may contain the additive (s) as needed.
Polyoxymethylene (A) may be used individually by 1 type, and may use 2 or more types together.

[Polyoxymethylene (A)]
Examples of polyoxymethylene (A) include polyoxymethylene homopolymer (a-1) and polyoxymethylene copolymer (a-2).

<Polyoxymethylene homopolymer (a-1)>
The polyoxymethylene homopolymer (a-1) is a polymer having only oxymethylene units in the main chain.
Both ends or one end of the polyoxymethylene homopolymer (a-1) may be blocked with an ester group or an ether group.
The polyoxymethylene homopolymer can be produced by the following (1) polymerization step and (2) terminal stabilization step using a monomer, chain transfer agent, and polymerization catalyst, which will be described later, using a predetermined reactor.

(1) Polymerization Step The polyoxymethylene homopolymer (a-1) can be produced by a known slurry polymerization method (for example, the method described in Japanese Patent Publication Nos. 47-6420 and 47-10059). it can. In the polymerization step, it can be obtained as a crude polyoxymethylene homopolymer whose terminals are not stabilized.

1) Monomer As a monomer used for manufacture of polyoxymethylene homopolymer (a-1), formaldehyde etc. are mentioned, for example.
In order to continuously obtain a polyoxymethylene homopolymer (a-1) having a stable molecular weight, it is preferable to use a formaldehyde gas that is purified and has a low impurity concentration and is stable. Examples of the purification method of formaldehyde include known methods (for example, the methods described in Japanese Patent Publication No. 5-32374 and Japanese Patent Publication No. 2001-521916).
When formaldehyde gas is used as the monomer, it is preferable that it contains as little impurities as possible, such as water, methanol, formic acid, and the like, which have a polymerization stopping action and a chain transfer action during the polymerization reaction. The fewer these impurities, the more unexpected chain transfer reaction can be avoided, and the desired molecular weight polyoxymethylene homopolymer (a-1) can be obtained. Among these, the content of impurities that induce hydroxyl groups in the polymer end groups is preferably 100 ppm by mass or less, and more preferably 50 ppm by mass or less, based on the total amount of monomers.

2) Chain transfer agent The chain transfer agent used for the production of the polyoxymethylene homopolymer (a-1) is not limited to the following, but alcohols, acid anhydrides and the like can be generally used. .
As the chain transfer agent, it is preferable to use a chain transfer agent that contains as little impurities as possible, such as water, methanol, formic acid, and acetic acid, in the polymerization reaction and the chain transfer effect. The method for obtaining a chain transfer agent having a small amount of impurities is not limited to the following. For example, a chain transfer agent that is widely used and has an available water content exceeding a specified amount is bubbled with dry nitrogen, A method of removing impurities with an adsorbent such as zeolite and purifying the material can be used.
A chain transfer agent may be used individually by 1 type, and may use 2 or more types together.

3) Polymerization catalyst The polymerization catalyst used for the production of the polyoxymethylene homopolymer (a-1) is not limited to the following, and examples thereof include an onium salt polymerization catalyst.
Examples of the onium salt-based polymerization catalyst include, but are not limited to, compounds represented by the following formula (1).
[R1R2R3R4M] ⁺ X ⁻ (1)
(In the formula (1), R1, R2, R3 and R4 each independently represents an alkyl group, M represents an element having a lone electron pair, X represents a nucleophilic group, and R1, R2, R3 and R4 represent , May be the same or different.)
Examples of the onium salt-based polymerization catalyst include, but are not limited to, quaternary ammonium salt compounds and quaternary phosphonium salt compounds, among which tetramethylammonium bromide and dimethyl distearyl. Ammonium acetate, tetraethylphosphonium iodide, and tributylethylphosphonium iodide are preferred.

4) Reactor The reactor used for the production of the polyoxymethylene homopolymer (a-1) is not limited to the following, but includes, for example, a reaction tank with a batch type stirrer, a continuous type kneader, two Examples thereof include an axial screw type continuous extrusion kneader and a biaxial paddle type continuous mixer.
The outer periphery of the reactor barrel preferably has a structure capable of heating or cooling the reaction mixture.

(2) Terminal Stabilization Step After the polymerization step (1), a terminal stabilization step is performed in which the terminal of the crude polyoxymethylene homopolymer is blocked with an ether group to perform terminal stabilization.
Examples of a method for stabilizing the end by blocking the end of the crude polyoxymethylene homopolymer with an ether group include known methods (for example, the method described in JP-B 63-452).
The etherifying agent in the case of blocking with an ether group is not limited to the following, and examples thereof include orthoester.
Examples of the orthoester include, but are not limited to, orthoesters of aliphatic acids or aromatic acids with aliphatic alcohols, alicyclic alcohols, or aromatic alcohols. Specific examples include methyl or ethyl orthoformate, methyl or ethyl orthoacetate and methyl or ethyl orthobenzoate, and ortho carbonate such as ethyl ortho carbonate.
An etherifying agent may be used individually by 1 type, and may use 2 or more types together.
The etherification reaction is carried out using a Lewis acid type catalyst such as p-toluenesulfonic acid, medium strength organic acids such as acetic acid and hydrobromic acid, medium strength mineral acids such as dimethyl and diethyl sulfate, etc. You may introduce 0.001-0.02 mass part with respect to a part.
The etherification reaction may be performed in the presence of a predetermined solvent. Examples of the solvent include, but are not limited to, low boiling point aliphatics such as pentane, hexane, cyclohexane, and benzene; alicyclic and aromatic hydrocarbons; methylene chloride, chloroform, carbon tetrachloride, and the like. And organic solvents such as halogenated lower aliphatic compounds.

The method of stabilizing the terminal by blocking the terminal of the crude polyoxymethylene homopolymer obtained in the polymerization step with an ester group is not limited to the following, but, for example, U.S. Pat. No. 3,459,709. Examples include a method in which a large amount of acid anhydride described in the specification is used in a slurry state, and a method in which gas is used in the gas phase using an acid anhydride gas described in US Pat. No. 3,172,736. .
Although it does not specifically limit as an esterifying agent in the case of blocking with an ester group, For example, an organic acid anhydride etc. are mentioned.
Examples of organic acid anhydrides include, but are not limited to, organic acid anhydrides represented by the following formula (2).
R5COOCOR6 (2)
(In Formula (2), R5 and R6 each independently represents an alkyl group or a phenyl group. R5 and R6 may be the same or different.)
Examples of organic acid anhydrides include, but are not limited to, propionic anhydride, benzoic anhydride, acetic anhydride, succinic anhydride, maleic anhydride, glutaric anhydride, phthalic anhydride, and the like. Acetic anhydride is preferred.
An esterifying agent may be used individually by 1 type, and may use 2 or more types together.
In the method of performing ester group blocking in the gas phase, it is preferable to perform terminal blocking after removing the onium salt polymerization catalyst by the method described in JP-A-11-92542. When the onium salt polymerization catalyst in the polyoxymethylene is removed, when the terminal is blocked, the decomposition reaction of the polyoxymethylene homopolymer (a-1) derived from the onium salt polymerization catalyst can be avoided, and the terminal is stabilized. The polymer yield in the reaction can be improved, and coloring of the polyoxymethylene homopolymer (a-1) can be suppressed.

The end of the polyoxymethylene homopolymer (a-1) is preferably blocked with an ether group and / or an ester group, so that the concentration of the terminal hydroxyl group is reduced to 5 × 10 ⁻⁷ mol / g or less. The concentration of the terminal hydroxyl group is preferably 5 × 10 ⁻⁷ mol / g or less because the thermal stability is excellent and the quality of the original polyoxymethylene homopolymer (a-1) can be maintained. The concentration of the terminal hydroxyl group is more preferably 0.5 × 10 ⁻⁷ mol / g or less, and further preferably 0.3 × 10 ⁻⁷ mol / g or less.

<Polyoxymethylene copolymer (a-2)>
The polyoxymethylene copolymer (a-2) is a copolymer having an oxymethylene unit in the main chain.
The comonomer unit may be a unit that can be copolymerized with the oxymethylene unit, and is not limited to the following, but is preferably an oxyalkylene unit having 2 or more carbon atoms, for example.
Both ends or one end of the polyoxymethylene copolymer (a-2) may be blocked with an ester group or an ether group, or both ends may be blocked.
In the polyoxymethylene copolymer (a-2), the comonomer unit is preferably contained in an amount of 0.3 mol or more, more preferably 0.4 mol or more, and more preferably 0.5 mol or more with respect to 100 mol of the oxymethylene unit. More preferably, the content is 0.6 mol or more, still more preferably 1.2 mol or more. In addition, the polyoxymethylene copolymer (a-2) preferably contains 3.0 mol or less of comonomer units, more preferably 2.0 mol or less, and even more preferably 1.5 mol or less.
By making the content ratio of the comonomer unit with respect to 100 mol of the oxymethylene unit within the preferable range, the composite part of the present embodiment is improved in productivity, and retains its appearance and is excellent in durability operation when used in a high temperature and high humidity environment. Tends to be obtained.
A polyoxymethylene copolymer can be produced by the following (1) polymerization step and (2) terminal stabilization step using a predetermined reactor using a main monomer, a comonomer, a chain transfer agent, and a polymerization catalyst described later. .

(1) Polymerization Step The polyoxymethylene copolymer (a-2) is not limited to the following, but known polymerization methods (for example, US Pat. No. 30,273,352, US Pat. No. 3,803,094, Germany) Japanese Patent No. 1161411, German Patent No. 1495228, German Patent No. 1720358, German Patent No. 3018898, Japanese Patent Laid-Open No. 58-98322 and Japanese Patent Laid-Open No. 7-70267. Can be produced by the method described in the publication. In the polymerization step, it can be obtained as a crude polyoxymethylene copolymer whose terminals are not stabilized.

1) Main monomer Examples of the main monomer used in the production of the polyoxymethylene copolymer (a-2) include cyclic oligomers such as formaldehyde or trioxane which is a trimer thereof or tetraoxane which is a tetramer.
In this embodiment, the “main monomer” refers to a monomer unit that is contained in an amount of 50% by mass or more based on the total amount of monomers.

2) Comonomer The comonomer used for the production of the polyoxymethylene copolymer (a-2) is not limited to the following. For example, a cyclic ether compound having an oxyalkylene unit having 2 or more carbon atoms in the molecule is used. Can be mentioned.
Examples of cyclic ether compounds include, but are not limited to, ethylene oxide, propylene oxide, 1,3-dioxolane, 1,3-propanediol formal, 1,4-butanediol formal, 1,5-pentane. Diol formal, 1,6-hexanediol formal, diethylene glycol formal, 1,3,5-trioxepane, 1,3,6-trioxycan, and mono- or di-glycidyl compounds that can form a branched or crosslinked structure in the molecule Can be mentioned.
A cyclic ether compound may be used individually by 1 type, and may use 2 or more types together.

When the polyoxymethylene copolymer (a-2) is polymerized, it is preferable that the main monomer and the comonomer do not contain impurities having a polymerization stopping action and a chain transfer action during polymerization reaction such as water, methanol and formic acid as much as possible. By using a main monomer and a comonomer containing as little impurities as possible, an unexpected chain transfer reaction can be avoided, and a polyoxymethylene copolymer (a-2) having a target molecular weight can be obtained. Among them, the content of impurities that induce hydroxyl groups in the polymer end groups is preferably 30 mass ppm or less, more preferably 10 mass ppm or less, and more preferably 3 mass ppm or less with respect to the total monomer amount. More preferably.
As a method for obtaining main monomers and comonomers having a small amount of impurities, known methods (for example, for the main monomers, the methods described in JP-A-3-123777 and JP-A-7-33761, And the method described in JP-A-49-62469 and JP-A-5-271217).

3) Chain transfer agent In the production of the polyoxymethylene copolymer (a-2), it is preferable to use a chain transfer agent.
The chain transfer agent is not particularly limited, and examples thereof include formaldehyde dialkyl acetals and oligomers thereof; lower aliphatic alcohols such as methanol, ethanol, propanol, isopropanol, and butanol. The alkyl group of the dialkyl acetal of formaldehyde is preferably a lower aliphatic alkyl group such as methyl, ethyl, propyl, isopropyl and butyl.
In order to obtain a long-chain branched polyoxymethylene copolymer (a-2), it is preferable to use polyether polyol and an alkylene oxide adduct of polyether polyol as a chain transfer agent.
As the chain transfer agent, a polymer having one or more groups selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, an ester group, and an alkoxy group may be used.
As the chain transfer agent, it is preferable to use a chain transfer agent that contains as little impurities as possible, such as water, methanol, formic acid, and acetic acid, which have a polymerization stopping action or a chain transfer action during the polymerization reaction. As a method for obtaining a chain transfer agent with few impurities, for example, a chain transfer agent that is widely used and has an available water content exceeding a specified amount is bubbled with dry nitrogen, and the impurities are removed with an adsorbent such as activated carbon or zeolite. And a purification method.
A chain transfer agent may be used individually by 1 type, and may use 2 or more types together. In any case, the polyoxymethylene copolymer (a-2) obtained preferably has a small number of unstable terminals.

4) Polymerization catalyst Although it does not specifically limit as a polymerization catalyst used for manufacture of a polyoxymethylene copolymer (a-2), Cationic active catalysts, such as Lewis acid, a protonic acid, and the ester or anhydride of a protonic acid, are preferable.
The Lewis acid is not particularly limited, and examples thereof include boric acid, tin, titanium, phosphorus, arsenic and antimony halides. Specific examples include boron trifluoride, tin tetrachloride, titanium tetrachloride, phosphorus pentafluoride, phosphorus pentachloride and antimony pentafluoride, and their complex compounds or salts.
Protic acids and protonic acid esters or anhydrides are not particularly limited, and examples thereof include perchloric acid, trifluoromethanesulfonic acid, perchloric acid-tertiary butyl ester, acetyl perchlorate, and trimethyloxonium hexafluorophosphate. Can be mentioned.
As the polymerization catalyst, boron trifluoride, boron trifluoride hydrate, a coordination complex compound of an organic compound containing an oxygen atom or a sulfur atom and boron trifluoride is preferable. Boron trifluoride diethyl ether, trifluoride Boron di-n-butyl ether is more preferred.
As a polymerization catalyst, you may use together the catalyst which reduces the production | generation of the terminal formate group described in Unexamined-Japanese-Patent No. 05-05017 as needed, for example.
The amount of the polymerization catalyst used is preferably 1 × 10 ⁻⁶ to 1 × 10 ⁻³ mol and more preferably 5 × 10 ⁻⁶ to 1 × 10 ⁻⁴ mol with respect to 1 mol of the total amount of all monomers. When the amount of the polymerization catalyst is within the above range, the reaction stability during polymerization and the thermal stability of the resulting polyoxymethylene resin part (P) are further improved.

The polymerization catalyst can be deactivated after the polymerization step by introducing the polymer into an aqueous solution or an organic solvent solution containing a catalyst neutralization deactivator and stirring in a slurry state for generally several minutes to several hours. it can.
Although it does not specifically limit as a catalyst neutralization deactivator, For example, Amines, such as ammonia, a triethylamine, and tri-n-butylamine; Alkali metal and alkaline-earth metal hydroxide; Inorganic acid salt; Organic acid salt etc. Is mentioned.
A catalyst neutralization deactivator may be used individually by 1 type, and may use 2 or more types together.
A method of deactivating a polymerization catalyst by contacting a vapor such as ammonia and triethylamine with a polyoxymethylene copolymer (a-2), or contacting with at least one of hindered amines, triphenylphosphine and calcium hydroxide in a mixer It is also possible to use a method in which the catalyst is deactivated.

5) Reactor The reactor used for the production of the polyoxymethylene copolymer (a-2) is not limited to the following. For example, a reaction tank with a batch type agitator, a continuous type kneader, biaxial Examples thereof include a screw type continuous extrusion kneader and a biaxial paddle type continuous mixer.
The outer periphery of the reactor barrel preferably has a structure capable of heating or cooling the reaction mixture.

(2) Terminal stabilization step After the polymerization step (1), a terminal stabilization step is performed in which the unstable terminal portion contained in the crude polyoxymethylene copolymer is decomposed and removed to stabilize the terminal.
The method for decomposing and removing the unstable terminal portion contained in the crude polyoxymethylene copolymer is not limited to the following. For example, a single screw extruder with a vent or a twin screw extruder with a vent is used. And a method of melting and kneading a crude polyoxymethylene copolymer in the presence of a known decomposition and removal agent to decompose and remove unstable terminal portions.
When performing melt-kneading for terminal stabilization, it is preferable to replace the atmosphere with an inert gas or to deaerate with a single-stage or multistage vent in order to maintain the quality and working environment. The temperature at the time of melt-kneading is preferably not lower than the melting point of the polyoxymethylene copolymer (a-2) and not higher than 250 ° C.

1) Decomposition remover The decomposition remover used for decomposing and removing the unstable terminal portion contained in the crude polyoxymethylene copolymer is not limited to the following, but, for example, aliphatic such as ammonia, triethylamine and tributylamine Examples thereof include basic substances such as amines; alkali metal or alkaline earth metal hydroxides such as calcium hydroxide; inorganic weak acid salts; and organic weak acid salts.
A decomposition removal agent may be used individually by 1 type, and may use 2 or more types together.
As the decomposition and removal agent, a method of treating a thermally unstable terminal with at least one quaternary ammonium compound represented by the following formula (3) can be suitably used.
[R7R8R9R10N ⁺ ] _n Y ⁿ⁻ (3)
(In Formula (3), R7, R8, R9 and R10 are each independently an unsubstituted alkyl group or substituted alkyl group having 1 to 30 carbon atoms; an aryl group having 6 to 20 carbon atoms; An unsubstituted alkyl group or an aralkyl group in which the substituted alkyl group is substituted by at least one aryl group having 6 to 20 carbon atoms; an aryl group having 6 to 20 carbon atoms is at least one unsubstituted alkyl group having 1 to 30 carbon atoms Any one selected from the group consisting of a group or an alkylaryl group substituted with a substituted alkyl group, n represents an integer of 1 to 3, Y represents a hydroxyl group, a carboxylic acid having 1 to 20 carbon atoms, or a hydrogen acid And any one of the acid residues selected from the group consisting of an organic thioacid having 1 to 20 carbon atoms, and R7, R8, R9 and R10 may be the same or different. .)
The unsubstituted alkyl group or substituted alkyl group in R7, R8, R9, and R10 may be any of linear, branched, and cyclic, and as a substituted alkyl group, an aryl group, an aralkyl group, and an alkylaryl group, And a group in which a hydrogen atom is substituted with a halogen.

Examples of the quaternary ammonium compound include, but are not limited to, tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetra-n-butylammonium, cetyltrimethylammonium, tetradecyltrimethylammonium, 1, 6-hexamethylene bis (trimethylammonium), decamethylene-bis- (trimethylammonium), trimethyl-3-chloro-2-hydroxypropylammonium, trimethyl (2-hydroxyethyl) ammonium, triethyl (2-hydroxyethyl) ammonium, tri Propyl (2-hydroxyethyl) ammonium, tri-n-butyl (2-hydroxyethyl) ammonium, trimethylbenzylammonium, triethylbenzyl Ammonium, tripropylbenzylammonium, tri-n-butylbenzylammonium, trimethylphenylammonium, triethylphenylammonium, trimethyl-2-oxyethylammonium, monomethyltrihydroxyethylammonium, monoethyltrihydroxyethylammonium, okdadecyltri (2- Hydroxyethyl) ammonium, tetrakis (hydroxyethyl) ammonium and the like.
Examples of the quaternary ammonium compound include quaternary ammonium hydrates such as hydrogen azide other than hydrohalic acid; sulfuric acid, nitric acid, phosphoric acid, carbonic acid, boric acid, chloric acid, iodic acid, silicic acid, Oxoacid salts such as perchloric acid, chlorous acid, hypochlorous acid, chlorosulfuric acid, amidosulfuric acid, disulfuric acid and tripolyphosphoric acid; thioic acid salts such as thiosulfuric acid; formic acid, acetic acid, propionic acid, butanoic acid, isobutyric acid Carboxylic acid salts such as pentanoic acid, caproic acid, caprylic acid, caprylic acid, benzoic acid and oxalic acid. Among them, hydroxide (OH ⁻ ), sulfuric acid (HSO ₄ ⁻ , SO ₄ ²⁻ ), carbonic acid (HCO ₃ ⁻ , CO ₃ ²⁻ ), boric acid (B (OH) ₄ ⁻ ), and carboxylic acid salts Is preferred. Of the carboxylic acids, formic acid and propionic acid are more preferred.

When a quaternary ammonium compound is added as a decomposition and removal agent, the amount of the quaternary ammonium compound added is nitrogen derived from the quaternary ammonium compound represented by the following formula (α) with respect to the crude polyoxymethylene copolymer. The amount added is preferably 0.05 to 50 ppm by mass in terms of the amount added.
Addition amount of quaternary ammonium compound = P × 14 / Q (α)
(In the formula (α), P represents the concentration (mass ppm) of the quaternary ammonium compound relative to the crude polyoxymethylene copolymer, “14” represents the atomic weight of nitrogen, and Q represents the molecular weight of the quaternary ammonium compound. .)

The decomposition removal agent may be added in advance before the crude polyoxymethylene copolymer is melted, or may be added to the melted crude polyoxymethylene copolymer.
As the decomposition and removal agent, ammonia, triethylamine and / or a boric acid compound and a quaternary ammonium compound may be used in combination.

[Additive (s)]
Examples of the additive (s) include, but are not limited to, an antioxidant, a stabilizer, a weathering (light) agent, a lubricant / release agent, a crystal nucleating agent, and an inorganic / organic filler. , Conductive agents / antistatic agents, appearance improvers (pigments, dyes, etc.) and the like.
The additive (s) preferably includes an antioxidant and a heat stabilizer. The antioxidant is preferably a hindered phenol antioxidant, and the heat stabilizer preferably contains formaldehyde-reactive nitrogen.
An additive (s) may be used individually by 1 type, and may use 2 or more types together.

<Antioxidant>
As the antioxidant, a hindered phenol antioxidant is preferably used.
Examples of the hindered phenol antioxidant include, but are not limited to, n-octadecyl-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) -propionate, n-octadecyl-3- (3′-methyl-5′-t-butyl-4′-hydroxyphenyl) -propionate, n-tetradecyl-3- (3 ′, 5′-di-t-butyl-4′- Hydroxyphenyl) -propionate, 1,6-hexanediol-bis- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) -propionate], 1,4-butanediol-bis- [3- (3,5-di-t-butyl-4-hydroxyphenyl) -propionate], triethylene glycol-bis- [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) Propionate], pentaerythritol tetrakis [methylene-3- (3 ', 5'-di -t- butyl-4'-hydroxyphenyl) propionate] methane, and the like. Preferably, triethylene glycol-bis- [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) -propionate] and pentaerythritol tetrakis [methylene-3- (3 ′, 5′-di-t -Butyl-4'-hydroxyphenyl) propionate] methane.
An antioxidant may be used individually by 1 type and may use 2 or more types together.

<Stabilizer>
As the stabilizer, a heat stabilizer is preferably used.
Examples of the heat stabilizer include, but are not limited to, nylon 4-6, nylon 6, nylon 6-6, nylon 6-10, nylon 6-12, nylon 12 and the like containing formaldehyde-reactive nitrogen. And a polyamide resin. The polyamide resin may be a copolymer such as nylon 6 / 6-6 / 6-10 or nylon 6 / 6-12.
Examples of the heat stabilizer include acrylamide and derivatives thereof, and copolymers of acrylamide and derivatives thereof with other vinyl monomers, and the like. It may be a poly-β-alanine copolymer obtained by polymerization in the presence.

Further, the heat stabilizer is not limited to the following, but examples include amide compounds, amino-substituted triazine compounds, adducts of amino-substituted triazine compounds and formaldehyde, condensates of amino-substituted triazine compounds and formaldehyde, urea, urea Derivatives, hydrazine derivatives, imidazole compounds, imide compounds and the like can be mentioned.
Examples of the amide compound include, but are not limited to, polycarboxylic acid amides such as isophthalic acid diamide, anthranilamides, and the like.
Examples of amino-substituted triazine compounds include, but are not limited to, 2,4-diamino-sym-triazine, 2,4,6-triamino-sym-triazine, N-butylmelamine, N-phenylmelamine N, N-diphenylmelamine, N, N-diallylmelamine, benzoguanamine (2,4-diamino-6-phenyl-sym-triazine), acetoguanamine (2,4-diamino-6-methyl-sym-triazine), Examples include 2,4-diamino-6-butyl-sym-triazine.
Examples of adducts of amino-substituted triazine compounds and formaldehyde include, but are not limited to, N-methylol melamine, N, N′-dimethylol melamine, N, N ′, N ″ -trimethylol melamine, and the like. Is mentioned.
Examples of the condensate of amino-substituted triazine compound and formaldehyde include, but are not limited to, melamine / formaldehyde condensate.
Examples of the urea derivative include, but are not limited to, N-substituted urea, urea condensate, ethylene urea, hydantoin compound, ureido compound, and the like. Specific examples of the N-substituted urea include methylurea substituted with a substituent such as an alkyl group, alkylenebisurea, and aryl substituted urea. Specific examples of urea condensates include urea and formaldehyde condensates. Examples of the hydantoin compound include, but are not limited to, hydantoin, 5,5-dimethylhydantoin, and 5,5-diphenylhydantoin. Examples of the ureido compound include, but are not limited to, allantoin.
As a hydrazine derivative, although not limited to the following, a hydrazide compound can be mentioned, for example. Examples of the hydrazide compound include, but are not limited to, dicarboxylic acid dihydrazide, and more specifically, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, spellin. Examples include acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, isophthalic acid dihydrazide, phthalic acid dihydrazide, and 2,6-naphthalenedicarbodihydrazide.
Examples of the imidazole compound include, but are not limited to, imidazole, 1-methylimidazole, 2-methylimidazole, and 1,2-dimethylimidazole.
Examples of the imide compound include, but are not limited to, succinimide, glutarimide, and phthalimide.

Examples of other stabilizers include, but are not limited to, alkali metal or alkaline earth metal hydroxides, inorganic acid salts, carboxylate salts, and alkoxides. , Hydroxides such as sodium, potassium, magnesium, calcium or barium, carbonates, phosphates, silicates, borates, carboxylates, and layered double hydroxides of the above metals.
The carboxylic acid of the carboxylate is preferably a saturated or unsaturated aliphatic carboxylic acid having 10 to 36 carbon atoms, and these carboxylic acids may be substituted with a hydroxyl group. Examples of the saturated or unsaturated aliphatic carboxylate include, but are not limited to, for example, calcium dimyristic acid, calcium dipalmitate, calcium distearate, (myristic acid-palmitic acid) calcium, (myristic acid) -Stearic acid) calcium, (palmitic acid-stearic acid) calcium, and the like are preferable, and calcium dipalmitate and calcium distearate are preferable.
Examples of the layered double hydroxide include hydrotalcites represented by the following formula (4).
[(M ²⁺ ) _1-X (M ³⁺ ) _X (OH) ₂ ] ^{X +} [(A ⁿ⁻ ) _{x / n} · mH ₂ O] X ⁻ (4)
(In the formula (4), M ²⁺ is a divalent metal, M ³⁺ is a trivalent metal, A ^n-n-valent (n represents an anion of an integer of 1 or more), X is, 0 <X ≦ 0 .33, and m represents a positive number.)
In the formula (4), examples of M ²⁺ include Mg ²⁺ , Mn ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ²⁺ , Zn ^2+, etc., and examples of M ^{3+ the, Al 3+, Fe 3+, Cr} 3+, Co 3+, etc. in ^3+, and examples of a ^{n- is, OH -, F -, Cl} -, Br -, NO 3- , CO ₃ ²⁻ , SO ₄ ²⁻ , Fe (CN) ₆ ³⁻ , CH ₃ COO ⁻ , oxalate ion, salicylate ion and the like. As an example of A ⁿ⁻ , OH ⁻ and CO ₃ ²⁻ are preferable.
Specific examples of hydrotalcites include natural hydrotalcite represented by Mg _0.75 Al _0.25 (OH) ₂ (CO ₃ ) _0.125 · 0.5H ₂ O, Mg _4.5 Al ₂ (OH) ₁₃ CO ₃ .3. Examples thereof include synthetic hydrotalcite represented by 5H ₂ O, Mg _4.3 Al ₂ (OH) _12.6 CO _{3, and the} like.
A stabilizer may be used individually by 1 type and may use 2 or more types together.

<Weatherproof (light) agent>
Examples of weathering (light) agents include, but are not limited to, benzotriazole ultraviolet absorbers, oxalic anilide ultraviolet absorbers, hindered amine light stabilizers, and the like.
Examples of the benzotriazole-based ultraviolet absorber include, but are not limited to, 2- (2′-hydroxy-5′-methyl-phenyl) benzotriazole, 2- (2′-hydroxy-3 ′), 5′-di-t-butyl-phenyl) benzotriazole, 2- [2′-hydroxy-3 ′, 5′-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- [2 ′ -Hydroxy-3 ′, 5′-bis- (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (2′-hydroxy-4′-octoxyphenyl) benzotriazole and the like.
Examples of oxalic acid alinide ultraviolet absorbers include, but are not limited to, 2-ethoxy-2′-ethyl oxalic acid bisanilide, 2-ethoxy-5-tert-butyl-2′-ethyl, for example. Examples thereof include oxalic acid bisanilide, 2-ethoxy-3′-dodecyl oxalic acid bisanilide, and the like. Preferably, 2- [2′-hydroxy-3 ′, 5′-bis- (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di -T-butyl-phenyl) benzotriazole and the like.
Specific examples of the hindered amine light stabilizer include N, N ′, N ″, N ′ ″-tetrakis- (4,6-bis- (butyl- (N-methyl-2,2,6,6-). Tetramethylpiperidin-4-yl) amino) -triazin-2-yl) -4,7-diazadecane-1,10-diamine, dibutylamine 1,3,5-triazine N, N′-bis (2, A polycondensate of 2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine and N- (2,2,6,6-tetramethyl-4-piperidyl) butylamine, poly [{6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidi L) imino}], dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol condensate, bis (2,2,6,6-tetramethyl-1) decanoate Reaction product of-(octyloxy) -4-piperidinyl) ester, 1,1-dimethylethyl hydroperoxide and octane, bis (1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5 -Bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butyl malonate, methyl-1,2,2,6,6-pentamethyl-4-piperidyl sebacate, bis (2,2,6, 6-tetramethyl-4-piperidyl) -sebacate, 1,2,3,4-butanetetracarboxylic acid and 1,2,2,6,6-pentamethyl-4-piperidinol and β, β, β ′, β ′ -Condensates with tetramethyl-3,9- [2,4,8,10-tetraoxaspiro (5,5) undecane] diethanol, etc. Preferably, bis (2,2,6,6-tetra Methyl-4-piperidyl) -sebacate, bis- (N-methyl-2,2,6,6-tetramethyl-4-piperidinyl) sebacate, 1,2,3,4-butanetetracarboxylic acid and 1,2, 2,6,6-pentamethyl-4-piperidinol and β, β, β ′, β′-tetramethyl-3,9- [2,4,8,10-tetraoxaspiro (5,5) undecane] diethanol and Is a condensate of
A weathering (light) agent may be used individually by 1 type, and may use 2 or more types together.

<Lubricant / Release agent>
Examples of the lubricant / release agent include, but are not limited to, alcohols, fatty acids and fatty acid esters thereof, polyoxyalkylene glycols, olefin compounds having an average degree of polymerization of 10 to 500, silicone, and the like. Can be mentioned.
A lubricant and a mold release agent may be used individually by 1 type, and may use 2 or more types together.

<Crystal nucleating agent>
Examples of the crystal nucleating agent include, but are not limited to, silicic acid such as talc, silica, quartz powder, glass powder, calcium silicate, aluminum silicate, kaolin, phyllite, clay, diatomaceous earth, and wollastonite. Metal oxides such as iron oxide, titanium oxide, and alumina; metal sulfates such as calcium sulfate and barium sulfate; carbonates such as calcium carbonate, magnesium carbonate, and dolomite; other silicon carbide, silicon nitride, boron nitride, various metals Examples thereof include finely divided solids of various crystal nucleation inorganic substances commonly known in polyoxymethylene resins such as powders.
As the crystal nucleating agent, boron nitride and talc are preferable.
For the crystal nucleation inorganic substance, a known surface treatment agent may be used in order to improve the affinity / dispersibility with the resin.
Examples of the surface treatment agent include, but are not limited to, for example, silane coupling agents such as amino silane and epoxy silane; titanate coupling agents, and fatty acids (saturated fatty acids and unsaturated fatty acids), alicyclics. Examples thereof include carboxylic acid, resin acid, and metal soap. The addition amount of the surface treatment agent is preferably 3% by mass or less, more preferably 2% by mass or less, with respect to the crystal nucleation inorganic substance.
A crystal nucleating agent may be used individually by 1 type, and may use 2 or more types together.

<Inorganic and organic fillers>
Examples of inorganic fillers include, but are not limited to, metal powders (aluminum, stainless steel, nickel, silver, etc.), oxides (silicon oxide, iron oxide, alumina, titanium oxide, zinc oxide, etc.) , Hydroxides (such as aluminum hydroxide, magnesium hydroxide, calcium hydroxide), silicates (such as talc, mica, clay, bentonite), carbonates (such as calcium carbonate, magnesium carbonate, hydrotalcite), carbon-based substances (Carbon black, graphite, carbon fiber, etc.), sulfate, boron nitride, silicon nitride and the like.
Examples of organic fillers include, but are not limited to, natural products (such as linter, wood, rice husk, silk, and leather) and synthetic systems (such as aramid, Teflon (registered trademark), and viscose). Is mentioned.
Among these, it is preferable to select from inorganic and organic fillers that can be added to conventional polyoxymethylene resins. In other words, adding a highly acidic / alkaline filler to polyoxymethylene resin may reduce the stability, so it has been added to the conventional polyoxymethylene resin, and it has been proven as a commercial product among inorganic and organic fillers. It is preferable to be selected.
The shape of the inorganic / organic filler may be any of powder, scale, plate, needle, sphere, fiber, tetrapod, and the like, and is not particularly limited.
As the inorganic / organic filler, a known surface treating agent may be used in order to improve the affinity with the resin. Examples of the surface treatment agent include, but are not limited to, silane coupling agents such as aminosilane and epoxysilane; titanate coupling agents, and fatty acids (saturated fatty acids and unsaturated fatty acids), alicyclics. Examples thereof include carboxylic acid, resin acid, metal soap, and resins. The addition amount of the surface treatment agent is preferably 3% by mass or less, and more preferably 2% by mass or less with respect to the inorganic / organic filler.
Inorganic / organic fillers may be used alone or in combination of two or more.

<Conducting agent / Antistatic agent>
Examples of the conductive agent include, but are not limited to, conductive carbon black, carbon nanotube or nanofiber or nanoparticle, metal powder or fiber, and the like.
Examples of the antistatic agent include, but are not limited to, for example, aliphatic polyethers (excluding compounds having a terminal fatty acid ester), aliphatic polyethers having a terminal fatty acid ester, and fatty acids. And a polyhydric alcohol fatty acid ester having a free hydroxyl group obtained from polyhydric alcohol, boric acid ester of glycerin monofatty acid ester, ethylene oxide adduct of amine compound, basic carbonate or anion exchanger thereof as a base. Examples thereof include an antistatic agent in which an alkylene polyol or an alkali metal salt-dissolved polyalkylene polyol is included.
A conductive agent and an antistatic agent may be used individually by 1 type, and may use 2 or more types together.

<Appearance improver>
Examples of the appearance improving agent include, but are not limited to, inorganic pigments and organic pigments, metallic pigments, and fluorescent pigments.
Inorganic pigments are those commonly used for coloring resins and are not limited to the following, but include, for example, zinc sulfide, titanium oxide, barium sulfate, titanium yellow, cobalt blue, Examples thereof include pigments, carbonates, phosphates, acetates, carbon black, acetylene black, and lamp black.
Examples of organic pigments include, but are not limited to, for example, condensed zozo, inone, furothocyanin, monoazo, diazo, polyazo, anthraquinone, heterocyclic, pennone, quinacridone And pigments such as thioindico, berylene, dioxazine, and phthalocyanine.
An appearance improving agent may be used individually by 1 type, and may use 2 or more types together.

The content of the additive (s) in the resin composition (p) is preferably 100 parts by mass or less and more preferably 50 parts by mass or less with respect to 100 parts by mass of the polyoxymethylene (A). More preferably, it is 25 parts by mass or less.
By setting the content of the additive (s) in a preferable range, the composite part including the resin part (P) made of the polyoxymethylene formed using the resin composition (p) has practically sufficient productivity. While securing, there is a tendency that excellent durability operability is obtained while maintaining the appearance in use in a high temperature and high humidity environment.

<Method for Producing Resin Composition (p)>
Regarding the method for producing the resin composition (p) using the polyoxymethylene (A) and, if necessary, the additive (s), the appearance is maintained while being used in a high-temperature and high-humidity environment, and the operation is durable. Although it will not specifically limit if it can be set as the composite component which is excellent in property, The manufacturing method of a resin composition (p) is demonstrated exemplarily below.

Mixing of polyoxymethylene (A) and, if necessary, additive (s) may be performed by adding additive (s) and granulating the polyoxymethylene (A) as necessary. Thus, the resin composition (p) can be obtained.
Further, after granulation of polyoxymethylene (A), an additive (s) is mixed as necessary using a Henschel mixer, tumbler or V-shaped blender, and then a kneader, a roll mill, a single screw extruder, two You may obtain a resin composition (p) by melt-kneading using a screw extruder or a multi-screw extruder.
The terminally stabilized polyoxymethylene (A) is preferably dried and melt kneaded and granulated while adding a stabilizer as an additive (s).
In the case of performing melt kneading, it is preferable to replace the atmosphere with an inert gas or to deaerate with a single-stage or multistage vent in order to maintain the quality and working environment. The temperature during melt-kneading is preferably not lower than the melting point of polyoxymethylene (A) and not higher than 250 ° C., and may be 20 to 50 ° C. higher than the melting point of polyoxymethylene (A).

In order to increase the dispersibility of the additive (s) with respect to the polyoxymethylene (A), a part or all of the polyoxymethylene (A) to be mixed was pulverized before mixing and mixed with the additive (s). Later, it may be melt-kneaded. In this case, the dispersibility may be further increased by using a spreading agent.
The spreading agent is not particularly limited, and examples thereof include aliphatic hydrocarbons and aromatic hydrocarbons, modified products thereof, and fatty acid esters of polyols.
A spreading agent may be used individually by 1 type, and may use 2 or more types together, such as a mixture of an aliphatic hydrocarbon, an aromatic hydrocarbon, and these modified substances.
The additive (s) may be divided several times and mixed with the polyoxymethylene (A).

  In the method for producing the resin composition (p), for example, a substance that supplements and neutralizes acetic acid is added as a condition for mixing the polyoxymethylene (A) and, if necessary, the additive (s). Water that coexists in an environment of 15 days at 80 ° C., for example, by selecting it as an agent or adjusting the terminal stabilization process and granulation timing, for example, by setting a predetermined time before granulation. The amount of acetic acid extracted to 150 g can be 100 mass ppm or less with respect to the mass of the resin component made of polyoxymethylene. In particular, it is preferable to adjust the conditions in the melt-kneading step during mixing.

  A molded product may be used as the resin composition (p) used in the present embodiment. For example, flakes obtained by taking out and pulverizing a polyoxymethylene resin part (P) from a composite part that has already been produced may be used as the resin composition (p). p) may be used.

<Characteristics of Resin Composition (p)>
As a characteristic of the resin composition (p), the melt flow rate (MFR) is preferably 0.6 to 60 g / 10 minutes, more preferably 0.9 to 45 g / 10 minutes, and 1.2. More preferably, it is ˜40 g / 10 min.
By making the MFR within a preferable range, the productivity of the composite part is improved, and when used in a high-temperature and high-humidity environment, the appearance tends to be maintained and excellent durability operability can be obtained.
In the present embodiment, the melt flow rate of the resin composition (p) is measured in accordance with ISO 1133 (Condition D, temperature 190 ° C.).
In the measurement of the melt flow rate, it may be measured using a polyoxymethylene resin part (P), and flakes obtained by pulverizing the polyoxymethylene resin part (P) are used as the resin composition (p). May be used.

When a polyoxymethylene copolymer containing an oxyalkylene unit is used in the resin composition (p), a ¹ H-NMR method is used for quantification of the oxyalkylene unit having 2 or more carbon atoms contained in the resin composition. The following procedure can be used.
The obtained resin composition (p) was dissolved with hexafluoroisopropanol so as to have a concentration of 1.5% by mass over 24 hours, and ¹ H-NMR analysis was performed using this solution, and oxymethylene unit and From the ratio of the integral value of the attribution peak of the oxyalkylene unit having 2 or more carbon atoms, the content ratio of the oxyalkylene unit (bmol) having 2 or more carbon atoms to the oxymethylene unit (a = 100 mol) (b / a: mol / 100 mol) can be determined.

<Method for producing polyoxymethylene resin part (P)>
The polyoxymethylene resin part (P) is obtained by molding the resin composition (p).
It does not specifically limit as a method of manufacturing the resin composition (P) made from polyoxymethylene, A well-known shaping | molding method is mentioned.
The molding method is not limited to the following. For example, extrusion molding, injection molding, vacuum molding, blow molding, injection compression molding, decorative molding, multicolor molding, gas assist injection molding, foam injection molding , Low pressure molding, ultra thin injection molding (ultra high speed injection molding), in-mold composite (insert molding, outsert molding), press molding and vacuum press molding.
As molding conditions, it is preferable to perform molding in a range where the resin temperature of the resin composition at the time of molding is 10 ° C. or higher from the melting point and 10 ° C. or lower from the decomposition temperature.

[Characteristics of composite parts]
The composite part of this embodiment includes a metal part (M) and a polyoxymethylene resin part (P).
In the composite part of this embodiment, the amount of acetic acid extracted into 150 g of water coexisting in an environment at 80 ° C. for 15 days is 100 ppm by mass or less with respect to the mass of the polyoxymethylene resin part.
The composite part of the present embodiment may include other resin parts other than the polyoxymethylene resin part (P). The resin constituting the other resin parts may be a thermosetting resin or a thermoplastic resin.
Other resin parts may be used alone or in combination of two or more.
Examples of the thermosetting resin include, but are not limited to, phenol resin, urea or melamine resin, unsaturated polyester resin, vinyl ester resin, diallyl phthalate resin, and epoxy resin.
Examples of the thermoplastic resin include, but are not limited to, polyethylene, polypropylene, styrene resins (polystyrene, acrylonitrile-styrene resin, ABS resin, etc.), general-purpose thermoplastic resins (vinyl chloride resin, methacrylic resin). , Polyethylene terephthalate and polyvinylidene chloride), engineering plastics (polyamide, polycarbonate, modified polyphenylene ether, polybutylene terephthalate, ultra high molecular weight polyethylene, etc.), super engineering plastics (polysulfone, polyphenylene sulfide, polyarylate, polyimide, polyether ether ketone, Liquid crystal polymer and fluororesin) and various elastomers.
Furthermore, it may be alloyed or copolymerized with one or more other resins or rubbers.
The resin constituting the other resin parts is preferably a thermoplastic resin from the viewpoint of productivity. Polypropylene, ABS resin, polyamide, polycarbonate, modified polyphenylene ether, poly (polyethylene ether), which are often used in resin parts as mechanical parts and electrical parts. Butylene terephthalate is more preferred.
Resins constituting other resin parts may be used alone or in combination of two or more.

(Characteristics of composite parts: amount of acetic acid extracted)
In the composite part of this embodiment, the amount of acetic acid extracted into 150 g of water coexisting in an environment left at 80 ° C. for 15 days is 100 ppm by mass or less based on the polyoxymethylene resin part (P). The amount of acetic acid is preferably 65 ppm by mass or less, and more preferably 50 ppm by mass or less.
When the amount of the acetic acid is within the above range, it is possible to obtain a composite part that retains the appearance and has excellent durability operability when used in a high temperature and high humidity environment.
In order to reduce the amount of acetic acid extracted to 150 g of water under the above conditions to 100 ppm by mass or less, for example, a monomer with less impurities is used, the resin is sufficiently washed, or before granulation. It is effective to take a predetermined time. As a result, acetic acid and substances that generate acetic acid contained in the composite part of this embodiment can be reduced. Further, the amount of acetic acid extracted into the water can be reduced by adding a substance capable of capturing and neutralizing acetic acid as an additive (s).
Furthermore, in order to reduce the amount of acetic acid volatilized into the system, the surface of a part that discharges acetic acid may be modified and coated.

(Characteristics of composite parts: amount of total organic carbon extracted)
In the composite part of this embodiment, the amount of total organic carbon extracted into 150 g of water coexisting in an environment left at 80 ° C. for 15 days is 500 mass relative to the mass of the polyoxymethylene resin part (P). It is preferably at most ppm, more preferably at most 350 mass ppm, further preferably at most 300 mass ppm.
When the amount of the total organic carbon is within the above range, it is possible to maintain an excellent appearance when used in a high-temperature and high-humidity environment, and to obtain a composite part having excellent durability operability. Become.
In order to reduce the amount of total organic carbon extracted to 150 g of water under the above conditions to 500 ppm by mass or less, for example, a method of improving the reaction rate or preventing contamination can be mentioned. Specifically, in the process of producing the resin composition (p), the polyoxymethylene (A) that has been sufficiently reacted is used to reduce thermal damage, and to reduce residual monomers and incorporated solvents. In addition, by reducing the mixing of unnecessary low-boiling oil and water-soluble substances into the resin composition (p), it is possible to reduce the mixing of all organic carbon into the composite part. As described above, the amount of total organic carbon extracted into water can be reduced to 500 ppm by mass or less.

In the composite part of the present embodiment, the test solution from which acetic acid and total organic carbon are extracted can be collected, for example, as follows.
A composite part of this embodiment including a metal part (M) and a polyoxymethylene resin part (P) is placed in a sealed container together with a beaker containing 150 g of water, and left in an oven at a temperature of 80 ° C. for 15 days. Then, the water in the beaker after returning to room temperature is used as the test solution.
The composite part may be measured after being decomposed into a metal part (M) and a polyoxymethylene resin part (P). At this time, it is confirmed that the change in the amount of water in the beaker is 10% by mass or less when left for 15 days.
If the amount changes beyond 10% by mass of 150 g, it is assumed that the vapor phase is large and the amount of evaporation is large, and the amount of water is adjusted so that the remaining water becomes 150 g after being left for 15 days. And measure.
As water, commercially available distilled water is preferably used, and it is preferable to use water having an acetic acid concentration of 0.1 mg / L or less and total organic carbon of 1 mg / L or less before measurement.
The air contained in the sealed container is a normal one, that is, left in an oven at a temperature of 80 ° C. for 15 days without any composite parts, and the increment of the concentration of acetic acid contained in the remaining 150 g of water is 0.1 mg / L. Hereinafter, those having an increase in total organic carbon concentration of 3 mg / L or less are used. A gas adjusted to 80 vol% nitrogen and 20 vol% oxygen may be used.
What is necessary is just to set the magnitude | size of an airtight container suitably according to the magnitude | size of a composite component.

For quantification of acetic acid, a generally known anion quantification method can be used. For example, quantification is performed by analyzing water before and after the test using an ion chromatograph (such as ICS-150 manufactured by Nihon Dynax Co., Ltd. and IC500 manufactured by Yokogawa Hewlett-Packard Co., Ltd.).
For quantification of total organic carbon (TOC), generally known methods for quantifying organic carbon in water can be used. For example, quantification is performed by analyzing the water before and after the test using a total organic carbon meter (such as TOC-VWS manufactured by Shimadzu Corporation and HT100 manufactured by Horiba Advanced Techno Co., Ltd.).

[Production method of composite parts]
The composite part of this embodiment can be manufactured by separately manufacturing and combining the metal part (M) and the polyoxymethylene resin part (P).
Moreover, you may manufacture the composite component of this embodiment by manufacturing the metal component (M) and polyoxymethylene resin component (P) which comprise this simultaneously.

[Usage of composite parts]
The composite component of the present embodiment is a component that is used by operating the metal component (M) and / or the polyoxymethylene resin component (P), or is used when the metal component (M) is energized. When it is a part, the effect of the present invention is particularly exhibited.
At this time, in use in a high-temperature and high-humidity environment, the external appearance is maintained and excellent durability operability is maintained.

When the composite part of this embodiment contains a buffer material, a rust preventive agent, hydraulic oil, grease, etc., the effect of this invention is exhibited especially. At this time, it has a tendency to maintain its appearance and maintain excellent durability operability when used in a high temperature and high humidity environment.
The metal part (M) and the polyoxymethylene resin part (P) in the composite part may or may not be in contact. Even if the metal part (M) surrounds the polyoxymethylene resin part (P), or the polyoxymethylene resin part (P) surrounds the metal part (M), or confronts like the bottom and lid of the container You may do it.

Although the specific form of the composite component of the present embodiment is not particularly limited, FIGS. 1 to 4 show schematic diagrams of examples.
FIG. 1 is a schematic perspective view of a configuration in which a composite part includes a polyoxymethylene resin part (P) such as a resin case or cover and a metal part (M) such as a substrate.
FIG. 2 is a schematic perspective view of a configuration in which the composite part includes a polyoxymethylene resin part (P) such as a resin case or cover, and a metal part (M) such as a shaft or bearing.
FIG. 3 is a schematic perspective view of a configuration in which the composite part includes a metal part (M) such as a metal wiring cable or wire and a polyoxymethylene resin part (P) such as a covering cover.
FIG. 4 is a schematic perspective view of a configuration in which the composite part includes a polyoxymethylene resin part (P) such as a resin mechanism part and a metal part (M) such as a metal case or cover.

  The composite part may include a part having a movable function in a part of the container, the cover, the case, the door, and the like. Moreover, you may have a shaft part, a bearing part, a shaft hole part, a roller part, a bush part, a washer part, a belt part, a fastening part, etc. which slide. Furthermore, it may have movable parts such as levers, handles, and pedals, rotating parts such as wheels and gears, unwinding / winding / guide parts for belts and tapes, and fitting parts such as assembly / removal. In addition, a battery or a power generation functional component may be provided as a circuit, a base, or a power source that functions by energization.

  Composite parts are used in electrical equipment, automotive parts and other various industrial parts. Examples of combinations of composite metal parts (M) and polyoxymethylene resin parts (P) include, for example, cases (metal devices, wiring boards and resin containers, etc.), tanks (metal gauges and pumps, etc.) Resin containers, etc.), cartridges (metal springs and shafts and resin casings and rollers, etc.), lights (metal lamps and resin covers, etc.), rollers (metal shafts and resin rollers, etc.), Belts (metal rollers and resin belts, etc.), gears (metal covers and resin gears, etc.), valves and piping (metal pipes and resin joints, etc.), meters (metal cases and resins, etc.) Measurement section and the like) and cords (metal wiring and resin coating section and the like).

  Hereinafter, although an example and a comparative example are given and the present invention is explained, this embodiment is not limited to the following examples. The evaluation method of the composite part in an Example and a comparative example is as follows.

[Amount of acetic acid extracted before and after high-temperature and high-humidity treatment of composite parts]
FIG. 5 shows a schematic plan view of the metal part (M) used for measurement.
FIG. 6 is a schematic plan view of a polyoxymethylene resin part (P) used for measurement.
As shown in the schematic diagram of FIG. 7, the metal part (M) and the polyoxymethylene resin part (P) were coexisted with 150 g of distilled water (manufactured by SIGMA-ALDRICH) in a beaker in a 2 L polypropylene container, It was left in a gear oven at 80 ° C. for 15 days for high temperature and high humidity treatment.
An ion chromatograph (Nippon Dionex Co., Ltd. ion chromatograph: ICS-1500, ion exchange column: IonPacAS1, column temperature: 30 ° C., eluent: 1 mM / L octanesulfonic acid, flow rate: 1 mL / min) Used to measure the amount of acetic acid extracted into water.
In this quantification method, peaks were detected at about 10 minutes for acetic acid, 8-9 minutes for formic acid, and 7-8 minutes for lactic acid.
Quantification was performed from the peaks and calibration curves detected before and after the high temperature and high humidity treatment, and the amount of acetic acid (mass ppm) relative to the mass of the polyoxymethylene resin part was measured.
It was confirmed that the amount of acetic acid in distilled water before the high-temperature and high-humidity treatment was not more than the detection limit of 0.1 mg / L.

[Total amount of organic carbon extracted before and after high-temperature and high-humidity treatment of composite parts]
FIG. 5 shows a schematic plan view of the metal part (M) used for measurement.
FIG. 6 is a schematic plan view of a polyoxymethylene resin part (P) used for measurement.
As shown in the schematic diagram of FIG. 7, the metal part (M) and the polyoxymethylene resin part (P) were coexisted with 150 g of distilled water (manufactured by SIGMA-ALDRICH) in a beaker in a 2 L polypropylene container, It was left in a gear oven at 80 ° C. for 15 days for high temperature and high humidity treatment.
Total carbon (TC) and inorganic carbon (IC) are measured using a total organic carbon meter (total organic carbon meter manufactured by Shimadzu Corporation: TOC-V CSN). The amount of total organic carbon extracted into water was measured and expressed as the amount of total organic carbon (mass ppm) relative to the mass of the polyoxymethylene resin part.
In addition, it confirmed that the quantity of the total organic carbon in distilled water before a high temperature, high humidity process was 1 mg / L or less.

[Appearance change evaluation of composite parts]
Changes in the appearance of the composite part before and after the high-temperature and high-humidity treatment were observed, and evaluation was performed after 3 days, 7 days, and 15 days according to the following evaluation criteria.
Three composite parts were evaluated and evaluated comprehensively.
(Evaluation criteria)
○: When the surface condition is good with no significant difference ◇: When discoloration is confirmed to be 5% or more and less than 10% of the entire surface area of the composite part △: Discolored to 10% or more and less than 40% of the surface area of the entire composite part ×: When discoloration, foreign matter, change in the thickness direction, etc. are confirmed in 40% or more of the surface area of the entire composite part, and the design properties are greatly reduced

[Durable operation evaluation of composite parts]
For the composite parts before and after the high temperature and high humidity treatment, using a reciprocating sliding tester (AFT-15MS type manufactured by Tokyu Seimitsu Co., Ltd.), as shown in the schematic diagram of FIG. The parts (P) were placed on the top and the metal parts (M) were placed on the bottom, and the durability operability was evaluated.
Durability operability was evaluated in a region surrounded by a small circle at the center shown in FIG.
The measurement conditions were a reciprocating distance of 20 mm, a reciprocating speed of 10 mm / sec, a load of 1 kg, an environmental temperature of 23 ° C., and a humidity of 50%.
Evaluation was performed by the change of the maximum friction coefficient when the number of reciprocations before and after the high temperature and high humidity treatment was up to 100 times. The maximum coefficient of friction before the high temperature and high humidity treatment was about 0.2 in all polyoxymethylene resin parts and metal parts. All the evaluations were performed three times, and the average was taken as the evaluation value.
(Evaluation criteria)
○: When the difference (average value) of the maximum friction coefficient before and after the high temperature and high humidity treatment is less than 20% ◇: The difference (average value) of the maximum friction coefficient before and after the high temperature and high humidity treatment is 20% or more and less than 40% Case Δ: When the difference (average value) of the maximum friction coefficient before and after the high temperature and high humidity treatment is 40% or more and less than 60% ×: The difference (average value) of the maximum friction coefficient before and after the high temperature and high humidity treatment is 60% or more, Or when sound is confirmed by sliding

[Metal parts (M)]
Metal parts (M-1) and (M-2) were used as the metal parts (M) constituting the composite member.
The following metal materials (m-1) and (m-2) were used as metal materials constituting the metal parts (M-1) and (M-2), respectively.
(M-1): Carbon steel (S45C / Nippon Steel & Sumikin Co., Ltd.)
(M-2): Galvanized steel sheet (Z27 / JFE Steel Co., Ltd.)
(M-3): Stainless alloy (SUS304 / Nippon Steel & Sumikin Stainless Steel Co., Ltd.)
As the metal materials (m-1) to (m-3), commercially available 1 mm flat plates were purchased.
Using a 1 mm flat plate of metal materials (m-1) and (m-2), a disk-shaped part having a diameter of 60 mm shown in FIG. 5 is machined to obtain metal parts (M-1) and (M-2). Obtained.
Next, using a 1 mm flat plate of a metal material (m-3), the bottom shown in FIG. 9A and the lid shown in FIG. 9B are manufactured, and these bottom and lid are combined. The container-shaped metal part (M-3) shown in 9 (C) was obtained.
It was confirmed that there were no burrs in the periphery.

[Polyoxymethylene resin parts (P)]
A polyoxymethylene resin part (P) was produced using the polyoxymethylene (A) and additive (s) shown below.
(1. Polyoxymethylene (A))
As polyoxymethylene (A), polyoxymethylene homopolymer (a-1) and polyoxymethylene copolymer (a-2) were prepared by the following procedure.
<Preparation of polyoxymethylene homopolymer (a-1)>
(Polymerization process)
A jacketed 5 L tank polymerization reactor having a circulation line (inner diameter: 6 mm, length: 2.5 m) and equipped with a stirrer was filled with 2 L of n-hexane. n-Hexane was circulated by a pump at 20 L / hr. 200 g / hr of dehydrated formaldehyde gas was directly supplied to this circulation line. The catalyst (dimethyl distearyl ammonium acetate) was adjusted to a formaldehyde gas at a molar ratio of 5 × 10 ⁻⁵ and supplied to the circulation line immediately before the reactor. Next, the chain transfer agent (acetic anhydride) is adjusted in the range of 0.1 to 0.6 g / hr to compensate for the decrease in the polymerization slurry sent to the terminal stabilization step, and supplied to n-hexane. Added and continuously fed. In this state, polymerization was performed at 58 ° C. to obtain a polymerization slurry. Adjustment of the addition amount of a chain transfer agent and a polymerization catalyst was performed so that the resin composition of the melt flow rate shown in Table 1 was obtained.

(Terminal stabilization process)
Stabilization was performed by reacting the obtained polymerization slurry in a 1: 1 mixture of n-hexane and acetic anhydride at 140 ° C. for 2 hours and acetylating the molecular terminals. The polymer after the reaction was collected by filtration to obtain a polyoxymethylene homopolymer (a-1) powder.

<Preparation of polyoxymethylene copolymer (a-2)>
(Polymerization process)
A self-cleaning type biaxial paddle type continuous mixing reactor with a jacket through which a heat medium can pass (screw diameter 3 inches, length ratio to diameter (L / D) = 10) was adjusted to 80 ° C. Trioxane as a main monomer, 3750 g / hr, 1,3-dioxolane as a comonomer, 25 to 150 g / hr, and chain transfer agent (methylal) adjusted in the range of 2.0 to 8.0 g / hr, continuously mixed The reactor was continuously fed. A 1% by mass cyclohexane solution of boron trifluoride di-n-butyl etherate as a polymerization catalyst was added to a continuous mixing reactor so that the catalyst was 2.0 × 10 ⁻⁵ mol with respect to 1 mol of trioxane. Polymerization was performed to obtain polymerized flakes (a-2). Adjustment of the addition amount of a chain transfer agent was performed so that the resin composition of the melt flow rate shown in Table 1 might be obtained.
After pulverizing the obtained polymerization flakes, the pulverized product was put into a 1% by mass aqueous solution of triethylamine and stirred to deactivate the polymerization catalyst. Thereafter, a 1% by mass aqueous solution of triethylamine containing polymer flakes was sequentially filtered, washed and dried to obtain a crude polymer.

(Terminal stabilization process)
It becomes 20 mass ppm when triethyl (2-hydroxyethyl) ammonium formate is converted into the quantity of nitrogen using the following formula (α) as a quaternary ammonium compound with respect to 1 part by mass of the obtained crude polymer. The amount equivalent was added and mixed uniformly, and then dried at 120 ° C. for 3 hours to obtain a dry polymer.
Addition amount of quaternary ammonium compound = P × 14 / Q (α)
Next, terminal stabilization was performed as follows using the obtained dry polymer. Add the obtained dry polymer to the front stage of a screw type twin screw extruder with a vent (Plastics Engineering Laboratory Co., Ltd., BT-30, L / D = 44, set temperature 200 ° C., rotation speed 80 rpm). Furthermore, 0.5 parts by mass of water was added to 100 parts by mass of the dry polymer, and vacuum degassing was performed while stabilizing the polymer terminal to obtain a polyoxymethylene copolymer (a-2).

(2. Additive (s))
The following additives (s-1) to (s-5) were used as the additive (s).
(S-1): Antioxidant / Irganox 245 (manufactured by Ciba Specialty Chemicals Co., Ltd.)
(S-2): Stabilizer / H-3 (manufactured by Asahi Kasei Finechem Co., Ltd.)
(S-3): Stabilizer / Sebacic acid dihydrazide (Nippon Finechem Co., Ltd.)
(S-4): Stabilizer / Adipic acid dihydrazide (manufactured by Nippon Finechem Co., Ltd.)
(S-5): Stabilizer / hydantoin (manufactured by Showa Denko KK)

[Preparation of Resin Composition (p) Included in Polyoxymethylene Resin Part (P)]
(Preparation of resin composition (p-1-1))
<Granulation process>
The polyoxymethylene homopolymer (a-1) collected by filtration was dried for 3 hours after the product temperature was confirmed to be 80 ° C. in a gear oven (80 ° C. setting) under a nitrogen atmosphere.
100 parts by mass of this polyoxymethylene homopolymer (a-1), 0.2 part by mass of additive (s-1) and 0.2 part by mass of additive (s-2) were mixed with a Henschel mixer. Mixed for minutes. Then, the obtained mixture was made into a screw type twin screw extruder with a vacuum vent set to 200 ° C. (manufactured by Plastic Engineering Laboratory, BT-30, L / D = 44, L: raw material of the twin screw extruder) The distance from the supply port to the discharge port (m), D: Inner diameter (m) of twin screw extruder, screw rotation speed 100 rpm, melt kneading at 24 amps, resin composition (p-1-1) Pellets were obtained.
The obtained pellets were dried in a gear oven (GPH-102, manufactured by ESPEC Corporation) at 80 ° C. for 2 hours before measurement. Melt flow of the resin composition (p-1-1) using a melt indexer (F-W01, manufactured by Toyo Seiki Co., Ltd.) in accordance with ISO 1133 (condition D, temperature 190 ° C.) The rate (MFR) was measured.
The obtained measurement results are shown in Table 1.

(Preparation of resin compositions (p-1-2) to (p-1-3))
The resin composition (except for the preparation of the polyoxymethylene homopolymer (a-1) by adjusting the addition amount of the chain transfer agent so that the melt flow rate resin composition shown in Table 1 was obtained. The pellet of the resin composition was obtained in the same procedure as p-1-1).

(Preparation of resin compositions (p-1-4) to (p-1-6))
In the above-described <granulation step>, the screw rotation speed is 80 rpm and the procedure is the same as that for the resin compositions (p-1-1) to (p-1-3), except that the melt kneading is performed at 20 amps. A pellet of the resin composition was obtained.

(Preparation of resin compositions (p-1-7) to (p-1-9))
In the <granulation step> described above, the product temperature was confirmed to be 80 ° C. in a gear oven (80 ° C. setting) in a nitrogen atmosphere, dried for 3 hours, and then left at room temperature for 24 hours to obtain a powder. Obtained the pellet of the resin composition in the procedure similar to resin composition (p-1-1)-(p-1-3), respectively.

(Preparation of resin compositions (p-1-10) to (p-1-12))
In the above <granulation step>, in addition to (s-1) and (s-2), 0.05 parts by mass of additives (s-3) to (s-5) were further added to each. The pellet of the resin composition was obtained in the same procedure as the resin composition (p-1-5).

(Preparation of resin compositions (p-1-13) to (p-1-15))
In the <granulation step> described above, after the product temperature was confirmed to be 80 ° C. in a gear oven (80 ° C. setting) in a nitrogen atmosphere and dried for 3 hours, the powder was left at room temperature for 24 hours to obtain a powder. <Granulation step> Resin composition in the same procedure as resin compositions (p-1-1) to (p-1-3), respectively, except that the screw rotation speed was 80 rpm and melted and kneaded at 20 amps. A product pellet was obtained.

(Preparation of resin composition (p-2-1) to (p-2-3))
<Granulation and kneading process>
Except for using the polyoxymethylene copolymer (a-2), the resin composition (p-2-1) was prepared in the same manner as the resin compositions (p-1-10) to (p-1-12), respectively. ) To (p-2-3) pellets were obtained.
The melt flow rate was measured in the same manner as the resin composition (p-1-1).
The melt flow rate of the obtained resin compositions (p-2-1) to (p-2-3) and the content ratio of the oxyalkylene unit b (mol) to the oxymethylene unit a (100 mol) (hereinafter referred to as “b / a” Are also shown in Table 1.
Here, (b / a) was obtained as follows.
The obtained resin composition is dissolved in a solvent hexafluoroisopropanol-d2 (D conversion rate 97%, Wako Pure Chemicals 98% assay) over 24 hours to prepare a 1.5% by mass solution. did. Using the obtained 1.5% by mass solution as a specimen, using a JEOL-400 nuclear magnetic resonance spectrometer ( ¹ H: 400 MHz), the oxymethylene unit a and the unit a The assigned peaks with the oxyalkylene unit b excluding were integrated. From the integrated value thus obtained, the content ratio of the oxyalkylene unit b (mol) to the oxymethylene unit a (100 mol) was determined.

[Manufacture of polyoxymethylene resin parts (P)]
Using an injection molding machine (J110AD manufactured by Nippon Steel Co., Ltd.), the resin composition (p) is set to a cylinder temperature 30 ° C. higher than the melting point, the mold temperature is 80 ° C., and the cooling time is 30 seconds. A polyoxymethylene resin part having a thickness (t) of 3 mm having a semicircular protrusion of 2.5 mm in diameter on a 60 mm square plate as shown in the schematic plan view of FIG. 6 was produced.
Molding of the polyoxymethylene resin part (P) was carried out while confirming that it was sufficiently filled and no burrs were produced.

[Examples 1-6], [Comparative Examples 1-3]
Examples 1 to 6 and Comparative Examples 1 to 3 were composite parts including a metal part (M) shown in FIG. 5 and a polyoxymethylene resin part (P) shown in FIG.
The evaluation results of the composite parts of Examples 1 to 6 and Comparative Examples 1 to 3 are shown in Table 2.
From the evaluation results of Examples 1 to 6 and Comparative Examples 1 to 3, the composite part has the characteristics of the present invention, so that excellent durability operability can be obtained while maintaining the appearance in a high temperature and high humidity environment. all right.

[Examples 7 to 15]
Examples 7 to 15 were composite parts including the metal part (M) shown in FIG. 5 and the polyoxymethylene resin part (P) shown in FIG.
The evaluation results of the composite parts of Examples 7 to 15 are shown in Table 3.
From the evaluation results of Examples 7 to 15, it was found that when the composite part has the characteristics of the present invention, it has a tendency to maintain its appearance and obtain excellent durability operability in a high temperature and high humidity environment.

[Example 16], [Comparative Example 4]
The evaluation results of the composite parts of Example 16 and Comparative Example 4 are shown in Table 3.
In Example 16 and Comparative Example 4, the metal part (M) used in Example 11 and Comparative Example 2 was used, and the same part as the oxymethylene resin part (P) was used.
In these, the container made from SUS304 of thickness 1mm of the container shape shown in FIG.9 (C) which combined the bottom part shown in FIG.9 (A) and the cover part shown in FIG.9 (B) was further used. .
As shown in FIG. 10, the metal part (M) and the oxymethylene resin part (P) are accommodated in the container of FIG. 9 (C), and the whole is a composite part (opening: relative to the surface area of the whole composite part) 20% or less).
In FIG. 10, the semicircular projection of the resin component (P) made of oxymethylene is fitted into the recess on the side surface of the bottom shown in FIG. 9A, and the projection protrudes from the side surface of the container. It has become.
In Example 16 and Comparative Example 4, instead of the metal part (M) and the polyoxymethylene resin part (P) in FIG. 7, as shown in FIG. 11, the composite part in FIG. Inside, it was made to coexist with 150 g of distilled water (manufactured by SIGMA-ALDRICH) in a beaker, left in a gear oven at 80 ° C. for 15 days, and subjected to high temperature and high humidity treatment, and the same evaluation as in Example 1 was performed. .
From the evaluation results of Example 16 and Comparative Example 4, it can be seen that the composite part has the characteristics of the present invention, so that it has a tendency to maintain its appearance and have excellent durability operability in a high temperature and high humidity environment. It was.

  The composite component of the present invention has industrial applicability in electrical and electronic applications, automotive applications, and other various industrial applications.

M metal parts P resin parts

Claims (6)

Including metal parts and polyoxymethylene resin parts,
The amount of acetic acid extracted into the water of the beaker after being put in a sealed 2 L polypropylene container together with a beaker containing 150 g of water and left in an oven at a temperature of 80 ° C. for 15 days and then returned to room temperature is The composite part which is 100 mass ppm or less with respect to the mass of the resin parts made from polyoxymethylene. Amount of total organic carbon extracted into beaker water after being placed in a sealed 2L polypropylene container with a beaker containing 150 g of water, left in an oven at a temperature of 80 ° C. for 15 days, and then returned to room temperature. The composite part according to claim 1, wherein is 500 ppm by mass or less based on the mass of the polyoxymethylene resin part.   The composite part according to claim 1, wherein the metal part is a steel-based metal. 4. The polyoxymethylene resin part and / or the metal part is a part that is used by being operated, or the metal part is a part that is used by being energized. 5. Composite parts as described in. A polyoxymethylene resin part included in the composite part according to any one of claims 1 to 4, wherein the polyoxymethylene resin part has a sliding portion with the metal part. A resin composition contained in a polyoxymethylene resin part included in the composite part according to any one of claims 1 to 4,
A resin composition having a melt flow rate (MFR) of 0.9 to 45 g / 10 min and containing a stabilizer.