JP2017222801A - Polyacetal resin molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyacetal resin molding with improved acid resistance.SOLUTION: A polyacetal resin molding contains a polyacetal resin composition. The polyacetal resin molding is at least partially coated with a hard coat layer that is a cured product of an ultraviolet-curable paint with a thickness of 2-300 μm, preferably 2-100 μm.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polyacetal resin molded article.

Polyacetal resin has high mechanical strength and rigidity, is excellent in oil resistance, organic solvent resistance and self-lubricating properties, is a resin that balances these in a wide temperature range, and has good workability. Therefore, as typical engineering plastics, they are widely used mainly for mechanical parts and sliding parts such as precision equipment, home appliances and OA equipment, automobiles, industrial materials, and miscellaneous goods.
In recent years, the field of use of polyacetal resin has been expanded, and the required performance has become higher at present.

Regarding the required performance, measures for damage to newly assumed polyacetal resin in existing molded products containing polyacetal resin, for example, when acid resistance is required as an additional required characteristic, measures to prevent damage due to acidic components are necessary It becomes. Therefore, in the polyacetal resin molded product, in addition to the mechanical properties, slidability, chemical resistance, design properties, etc., inherently possessed by the polyacetal resin, it is possible to stably obtain a molded product having further excellent acid resistance, There is a need for polyacetal resin compositions.
As a method for improving the “acid resistance”, it may be mentioned as a solution method to additionally install a part such as a protective cover so as to physically prevent contact with acidic components. There is a problem that restrictions on the component configuration are large.
For this reason, conventionally, a resin composition of an acid-resistant polyacetal resin with improved acid resistance has been proposed (see, for example, Patent Document 1).

  In addition, regarding various engineering resins such as polyacetal resin, polybutylene terephthalate resin, polyamide resin, etc., by providing a protective layer made of polyolefin resin of 0.3 mm to 3 mm on the exposed part where these are exposed to the outside air, Techniques that improve acid resistance and alkali resistance have been proposed (see, for example, Patent Document 2).

On the other hand, although polyacetal resin is not highly resistant to acids and alkalis, it has a relatively high chemical resistance to other chemicals such as organic solvents and oils and fats. Further, it is difficult to ensure the adhesion between the polyacetal resin and the coating layer, and there is a problem that it is not suitable for reforming the surface of a molded product with other components.
In addition, highly transparent thermoplastic resins such as polycarbonate resin, acrylic resin, polyethylene terephthalate (hereinafter also simply referred to as “PET”) resin, etc. are light weight, inexpensive, transparent, and excellent in impact resistance. However, these thermoplastic resins have a problem that their surfaces are easily damaged and their transparency is impaired when they are damaged. For the purpose of solving such problems, it is common to coat the surface with a coat layer, particularly regarding a hard coat film-forming coating material, a hard coat film, and a resin composition coated with a hard coat film. Many techniques have been proposed (see, for example, Patent Document 3 and Patent Document 4).

Japanese Patent No. 5297640 JP 2010-214619 A JP 2008-138160 A JP 2012-168377 A

  However, in the molded article using the polyacetal resin excellent in acid resistance proposed in Patent Document 1, each retention ratio of weight, strength, and elongation at break with respect to a 5% hydrochloric acid aqueous solution and a 40% acetic acid aqueous solution is used. However, in reality, it is not limited to a case where a molded article using a polyacetal resin is used in an environment where it is in contact with a low concentration acidic aqueous solution for a long time. Document 1 has a problem that it does not necessarily match actual use. That is, contrary to the above case, it is necessary to assume that a high concentration acidic aqueous solution is contacted for a short time. For example, for some products, it is necessary to assume that the contact time between the acidic aqueous solution and the product is from the adhesion of the acidic aqueous solution to evaporation.

  In Patent Document 2, regarding engineering resins such as polyacetal resin, polybutylene terephthalate resin, and polyamide resin, a protective layer made of polyolefin resin of 0.3 mm to 3 mm is provided on an exposed portion where these resins are exposed to the outside air. Technology has been proposed to eliminate the problems related to low acid resistance and alkali resistance of the various engineering resins by providing, for example, a double-molded or two-color molded polyacetal resin and polyolefin resin, Due to the low adhesion of these interfaces, there is a problem that sufficient acid resistance and alkali resistance cannot be ensured.

  Furthermore, Patent Documents 3 and 4 disclose techniques for improving the scratch resistance of highly transparent thermoplastic resins such as polycarbonate resins, acrylic resins, and PET resins, but improving acid resistance of polyacetal resin molded products. There is no mention of an effective method for.

  Accordingly, an object of the present invention is to provide a polyacetal resin molded product with improved acid resistance.

As a result of intensive studies to solve the above-described problems of the prior art, the present inventors have a configuration in which at least a part of the polyacetal resin molded product is covered with a coating layer having a film thickness within a predetermined range. As a result, it was found that the acid resistance was improved, and the present invention was completed.
That is, the present invention is as follows.

[1]
A polyacetal resin molded article comprising a polyacetal resin composition,
At least a part is covered with a coating layer having a thickness of 2 μm or more and 300 μm or less,
Polyacetal resin molded product.
[2]
The polyacetal resin molded product according to [1], wherein the coating layer has a thickness of 2 μm or more and 100 μm or less.
[3]
The polyacetal resin molded product according to [1] or [2], wherein the coat layer is a cured product of an ultraviolet curable paint.
[4]
The polyacetal resin molded product according to any one of [1] to [3], wherein the coat layer is a coat layer formed of a hard coat film forming paint.

  According to the present invention, a polyacetal resin molded product having excellent acid resistance can be obtained.

The schematic perspective view of an example of the polyacetal molded article of this embodiment is shown. FIG. 2 shows an image diagram illustrating a process of obtaining a prepared polyacetal copolymer (component A) from a dry polymer. Polyacetal resin composition from pellets of prepared polyacetal copolymer consisting of component A, additive component (component B) supplied from hopper, other additives, and components such as additive supplied from side feeder (component C) The image figure which shows the process of obtaining a thing is shown (components, such as an additive, point out coloring materials, such as a stabilizer, a filler, and a pigment other than the pellet and additive of an adjustment polyacetal copolymer).

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

[Polyacetal resin molded product]
The polyacetal resin molded product of this embodiment is
A polyacetal resin molded article comprising a polyacetal resin composition,
At least a portion is covered with a coating layer having a thickness of 2 μm or more and 300 μm or less.

(Polyacetal resin composition)
The polyacetal resin molded product of the present embodiment is a molded product using the polyacetal resin composition.
The polyacetal resin composition contains a polyacetal resin and other various additives.
The polyacetal resins are roughly classified into two types: polyacetal homopolymers (hereinafter also simply referred to as “homopolymers”) and polyacetal copolymers (hereinafter also simply referred to as “copolymers”), and molded products are used as products. Depending on the environment to be used, required performance, etc., these two types are selected as appropriate.
Moreover, you may use together the said polyacetal homopolymer and a polyacetal copolymer.

The fluidity of the polyacetal resin composition is not particularly limited, and is selected depending on the required performance and moldability of the molded product used.
The fluidity of the polyacetal resin composition is standard and preferably about 9.0 g / 10 min as a melt flow rate (hereinafter also referred to as “MFR”) value. As a method for measuring the melt flow rate, there is a method of measuring in accordance with ISO standard 1133 condition D, and in particular, a measured value under a measurement temperature of 190 ° C. and a load of 2.16 kg is generally adopted.
The polyacetal resin composition is a polymer having a high fluidity, for example, an MFR value of 9.0 g when used for a product having a small wall thickness, a product having a long flow length from the gate to the flow end, or a product having a high required dimensional accuracy. It is preferred to select polymers higher than / 10 minutes, and when used in products that are intermittently and continuously loaded, select polymers with high viscosity, for example polymers with MFR values lower than 9.0 g / 10 minutes It is preferable.
The MFR of the polyacetal resin composition is preferably adjusted to 2.5 g / 10 min or more and 40 g / 10 min or less because the productivity and the weld properties of the molded body tend to be better maintained. Furthermore, it is more preferable to adjust to 3.0 g / 10 minutes or more and 30 g / 10 minutes or less, and it is further more preferable to adjust to 3.5 g / 10 minutes or more and 25 g / 10 minutes or less.

  Since the polyacetal resin used for the polyacetal resin molded product of the present embodiment is a polyacetal homopolymer, high impact properties and durability can be maintained when formed into a molded product, which is preferable.

The polyacetal homopolymer of this embodiment can be obtained by the polymerization process shown below.
The polyacetal homopolymer can be obtained by a known slurry polymerization method (see, for example, Japanese Patent Publication Nos. 47-6420 and 47-10059). Specifically, a monomer that is a raw material is polymerized in the presence or absence of a chain transfer agent, and in the presence or absence of a polymerization catalyst, to thereby form a polyacetal homopolymer that has not been terminally stabilized. A certain crude polyacetal can be obtained.

As a monomer which is a raw material of the polyacetal homopolymer, formaldehyde can be preferably exemplified.
Such formaldehyde is not particularly limited, but is preferably a formaldehyde gas that is purified, has a low impurity concentration, and is stable in order to continuously obtain a resin having a stable molecular weight.
As a purification method of formaldehyde, a known method (for example, see Japanese Patent Publication No. 5-32374 and Japanese Patent Publication No. 2001-521916) can be used.
Examples of the impurities include water, methanol, formic acid, etc., which have a polymerization termination or chain transfer action during the polymerization reaction. By preventing these impurities from being excessively present, it is possible to achieve the purpose by an unexpected chain transfer reaction. It tends to be possible to prevent the molecular weight product from being obtained. The content of water as an impurity is preferably 100 mass ppm or less, and more preferably 50 mass ppm or less.

In the polymerization step of the polyacetal homopolymer, it is preferable to use a chain transfer agent. Examples of such chain transfer agents include, but are not limited to, alcohols and acid anhydrides (for example, acetic anhydride).
Moreover, as a chain transfer agent for obtaining the polyacetal homopolymer of a block polymer or a branched polymer, although not limited to the following, For example, a polyol, polyether polyol, and polyether polyol alkylene oxide are also mentioned.
These chain transfer agents may be used alone or in combination of two or more.
The chain transfer agent preferably does not contain impurities as much as possible, similarly to the monomer that is a raw material of the polyacetal homopolymer. The content of water as an impurity is preferably 2,000 mass ppm or less, and more preferably 1,000 mass ppm or less. As a method for obtaining a chain transfer agent with a small amount of impurities, for example, when the water content of the obtained chain transfer agent exceeds a specified value, after bubbling with dry nitrogen, an adsorbent such as activated carbon or zeolite is used. The method of adjusting to content of the target water by removing an impurity and refine | purifying is mentioned.

In the polymerization step of the polyacetal homopolymer, it is preferable to use a polymerization catalyst. Although not limited to the following as a polymerization catalyst, For example, the onium salt type polymerization catalyst represented by following General formula (1) is mentioned.
[R ¹ R ² R ³ R ⁴ M] ⁺ X ⁻ (1)
In the formula (1), R ¹ , R ² , R ³ , and R ⁴ each independently represents an alkyl group, M represents an element having an independent electron pair, and X represents a nucleophilic group.

  Among the onium salt-based polymerization catalysts represented by the formula (1), quaternary ammonium salt compounds and quaternary phosphonium salt compounds are preferable, and tetramethylammonium bromide, dimethyl distearyl ammonium iodide, and Dimethyl distearyl ammonium acetate.

The polymerization step of the polyacetal homopolymer is not particularly limited, but can be performed using a conventionally known reactor.
Examples of the reactor include, but are not limited to, a reaction tank with a batch type agitator, a continuous type kneader, a twin screw type continuous extrusion kneader, and a twin screw paddle type continuous mixer. It is done.
As the reactor, a reactor having a structure capable of heating and cooling the reaction mixture is preferable.

It is preferable that the polyacetal homopolymer obtained by the said polymerization process performs the process (terminal stabilization process) which stabilizes the terminal.
The method for stabilizing the terminal is not limited to the following. For example, as shown below, the terminal is blocked with an ethyl group, the terminal is blocked with an acetyl group, and the terminal is an ester group. The method of sealing with is mentioned.

Examples of the method of blocking the end with an ethyl group (ethylation reaction) include the method described in JP-B 63-452.
Further, as a method for blocking the end with an acetyl group (acetylation reaction), for example, a method in which a large amount of acid anhydride described in US Pat. No. 3,459,709 is used in a slurry state, and the US The method of performing in the gaseous phase using the acid anhydride gas as described in patent 3,172,736 is mentioned.
In the method of blocking the terminal with an ethyl group, examples of the ethylating agent to be used include orthoester. Specific examples include, but are not limited to, orthoesters of aliphatic or aromatic acids with aliphatic, alicyclic or aromatic alcohols, specifically methyl or ethyl orthoformate. , Ortho esters such as methyl or ethyl orthoacetate, methyl or ethyl orthobenzoate, and orthocarbonates such as ethyl orthocarbonate.
In the ethylation reaction, Lewis acid type catalysts such as medium strength organic acids such as p-toluenesulfonic acid, acetic acid, and hydrobromic acid, and medium strength mineral acids such as dimethyl and diethyl sulfate are used for the above ethylation. It is preferable to carry out by introducing 0.001 part by mass or more and 0.02 part by mass or less with respect to 1 part by mass of the agent.
The solvent used for the ethylation reaction is not particularly limited, but low-boiling point aliphatic, alicyclic, and aromatic hydrocarbons such as pentane, hexane, cyclohexane, and benzene, and halogens such as aromatic hydrocarbons, methylene chloride, chloroform, and carbon tetrachloride. Preferred is an organic solvent of a modified lower aliphatic compound.

On the other hand, when the end of the homopolymer is blocked with an ester group, examples of the organic acid anhydride used for esterification include organic acid anhydrides represented by the following general formula (2).
R ¹ COOCOR ² (2)
In the formula (2), R ¹ and R ² each independently represents an alkyl group or an aryl group. R ¹ and R ² may have the same structure or different structures.
Among the organic acid anhydrides represented by the formula (2), propionic anhydride, benzoic anhydride, acetic anhydride, succinic anhydride, maleic anhydride, glutaric anhydride, and phthalic anhydride are preferable, and acetic anhydride is more preferable. preferable.
Moreover, only one type of organic acid anhydride may be used alone, or two or more types may be used in combination.
In the method of performing ester group blocking in the gas phase, if the onium salt polymer catalyst remains in the homopolymer, the onium salt polymerization catalyst promotes the decomposition reaction of the homopolymer when end-blocking. As a result, the polymer yield in the terminal stabilization step is significantly reduced and the homopolymer may be colored. For example, the onium salt-based polymerization catalyst is removed by the method described in JP-A-11-92542. After that, it is preferable to perform end-capping.

By blocking the end of the homopolymer with an ethyl group and / or an ester group, the concentration of the terminal hydroxyl group is preferably reduced to 5 × 10 ⁻⁷ mol / g or less, and to 0.5 ⁻⁷ mol / g or less. More preferably, it is reduced.
The homopolymer that has undergone terminal stabilization is preferably pelletized using an extruder in order to ensure handling after the drying treatment.

The polyacetal resin used in the polyacetal resin molded product of the present embodiment is preferably a polyacetal copolymer, and thus is excellent in heat aging characteristics, hydrolysis resistance, and chemical resistance when formed into a molded product.
The polyacetal copolymer used in the polyacetal resin molded article of the present embodiment is not particularly limited, but is preferably a polymer having an oxymethylene group in the main chain and an oxyalkylene unit having 2 or more carbon atoms in the molecule.

The polyacetal copolymer can be obtained by the polymerization process described below.
In addition to the method described in the present specification, the polymerization step for obtaining a polyacetal copolymer may be a known polymerization method (for example, US-A-3027352, US-A-3803094, DE-C-11141421, DE-C- 1495228, DE-C-1720358, DE-C-3018898, JP-A-58-98322, JP-A-7-70267).
By the polymerization step, a crude polymer of polyacetal copolymer is obtained.

The main monomer, which is the main raw material of the polyacetal copolymer, is not particularly limited, but is preferably a cyclic oligomer such as formaldehyde, trioxane that is a trimer thereof, or tetraoxane that is a tetramer.
The monomer that is not the main raw material of the polyacetal copolymer (a monomer having a smaller content in the copolymer than the main monomer, hereinafter referred to as “comonomer”) is not particularly limited, but, for example, an oxyalkylene having 2 or more carbon atoms in the molecule The cyclic ethyl compound which has a unit is mentioned. Among them, ethylene oxide, propylene oxide, 1,3-dioxolane, 1,3-propanediol formal, 1,4-butanediol formal, 1,5-pentanediol formal, 1,6-hexanediol formal, diethylene glycol formal, 1 1,3,5-trioxepane, 1,3,6-trioxocan, and a mono- or di-glycidyl compound capable of forming a branched or crosslinked structure in the molecule are preferably used.

  The amount of copolymerization of the comonomer component of the polyacetal comonomer is 100 mol of trioxane when the main monomer is converted to trioxane (formaldehyde trimer) from the viewpoint of improving the mechanical properties such as stability in the polymerization reaction, strength and rigidity. On the other hand, 1.0 mol or more and 10 mol or less are preferable, and 1.0 mol or more and 5.0 mol or less are more preferable.

As the main monomer and comonomer, it is preferable to use one that contains as little impurities as possible, such as water, methanol, formic acid, or the like, which has a polymerization termination or chain transfer action during the polymerization reaction.
This is because water, methanol, and formic acid are impurities that induce polymer end groups to hydroxyl groups. By making these impurities not excessively present, it tends to be possible to prevent the desired molecular weight product from being obtained due to an unexpected chain transfer reaction.
As a method for obtaining a desired low-impurity main raw material, a known method (for example, JP-A-3-123777 and JP-A-7-33761 for the main monomer, JP-A-49-62469 for the comonomer) is known. And Japanese Patent Application Laid-Open No. 5-271217).

In the polymerization step of the polyacetal copolymer, it is preferable to use a chain transfer agent.
Examples of the chain transfer agent include, but are not limited to, a dialkyl acetal of formaldehyde (for example, methylal) and an oligomer thereof in which the alkyl group is a lower aliphatic alkyl group such as methyl, ethyl, propyl, isopropyl, and butyl; Lower aliphatic alcohols such as methanol, ethanol, propanol, isopropanol and butanol are preferred.
In order to obtain a long-chain branched polyacetal copolymer, polyether polyol and polyether polyol alkylene oxide are preferable as the chain transfer agent.
In order to obtain a block polyacetal copolymer, it is also preferable to chain transfer a polymer having at least one hydroxyl group, carboxyl group, amino group, ester group, or alkoxy group and having a number average molecular weight of 400 or more. .
In addition, the said chain transfer agent may be used individually by 1 type, or may use 2 or more types together.
Among these chain transfer agents, those having less unstable terminal formation are preferred.

In the polymerization step of the polyacetal copolymer, it is preferable to use a polymerization catalyst.
The polymerization catalyst for the polyacetal copolymer is not limited to the following, but for example, cationically active catalysts such as Lewis acids, proton acids, and esters or anhydrides thereof are preferable.
Examples of Lewis acids include boric acid, tin, titanium, phosphorus, arsenic, and antimony halides. Specifically, boron trifluoride, tin tetrachloride, titanium tetrachloride, phosphorus pentafluoride, pentafluoride, and the like. Examples thereof include phosphorus chloride, antimony pentafluoride, and complex compounds or salts thereof.
Examples of the protonic acid, ester or anhydride thereof include perchloric acid, trifluoromethanesulfonic acid, perchloric acid-tertiary butyl ester, acetyl perchlorate, and trimethyloxonium hexafluorophosphate.
Among these, boron trifluoride; boron trifluoride hydrate; and a coordination complex compound of an organic compound containing an oxygen atom or a sulfur atom and boron trifluoride are preferable. Specifically, boron trifluoride Preferred examples include diethyl ether and boron trifluoride di-n-butyl ether.
The amount of the polymerization catalyst used is such that the reaction stability at the time of polymerization and the thermal stability of the molded product tend to be further improved, so the total amount of trioxane and cyclic ethyl and / or cyclic formal is 1 mol. It is preferably 1.0 × 10 ⁻⁶ mol or more and 1.0 × 10 ⁻³ mol or less, more preferably 5.0 × 10 ⁻⁶ mol or more and 1.0 × 10 ⁻⁴ mol or less.
In the polymerization step of the polyacetal copolymer, a cocatalyst may be used as necessary.

In the production process of the polyacetal copolymer used for the polyacetal resin molded article of the present embodiment, it is preferable to perform a process (terminal stabilization process) of decomposing and removing unstable terminal parts contained in the copolymer obtained by the polymerization process.
The method for decomposing and removing the unstable terminal portion is not particularly limited. For example, a decomposing / removing method that is a known basic substance using a vented single-screw extruder or a vented twin-screw extruder is used. In the presence of the agent, there is a method in which the crude polymer is melted to decompose and remove unstable terminal portions.
Here, when performing melt-kneading for terminal stabilization, it is preferable to perform deaeration by substitution with an inert gas or single-stage and multistage vents in order to maintain the quality and working environment.
The melt kneading temperature is preferably not lower than the melting point of the polyacetal copolymer and not higher than 260 ° C.
Furthermore, in the terminal stabilization step, it is preferable to perform granulation by adding a known stabilizer that can be added to the polyacetal resin, and granulating. Moreover, you may melt-knead, adding the hindered amine type material mentioned later previously at the time of this granulation.

The decomposition / removal agent used in the method for removing the unstable terminal portion is not particularly limited. For example, aliphatic amines such as ammonia, triethylamine, and tributylamine; alkali metals and alkaline earth metals represented by calcium hydroxide And known basic substances such as hydroxides, inorganic weak acid salts and organic weak acid salts.
Among the decomposition / removal agents, at least one quaternary ammonium compound represented by the following general formula (3) is preferable. In the polyacetal copolymer stabilized by the decomposition / removal agent, unstable terminals are present. There is a tendency that the portion does not easily remain.
[R ¹ R ² R ³ R ⁴ N ⁺ ] _n X ^n- (3)
In the formula (3), R ¹ , R ² , R ³ , and R ⁴ 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; carbon An alkylaryl group in which an aralkyl group having 6 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms is substituted with at least one unsubstituted alkyl group having 1 to 30 carbon atoms or a substituted alkyl group is shown.
The unsubstituted alkyl group and the substituted alkyl group are linear, branched, or cyclic.
The aryl hydrogen atom in the aryl group, aralkyl group and alkylaryl group may be substituted with a halogen.
n shows the integer of 1-3. X represents a hydroxyl group or an acid residue of a carboxylic acid having 1 to 20 carbon atoms, a hydrogen acid, an oxo acid inorganic thioacid, or an organic thioacid having 1 to 20 carbon atoms.

The quaternary ammonium compound is not particularly limited. For example, tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetra-n-butylammonium, cetyltrimethylammonium, tetradecyltrimethylammonium, 1,6-hexamethylenebis (Trimethylammonium), decamethylene-bis- (trimethylammonium), trimethyl-3-chloro-2-hydroxypropylammonium, trimethyl (2-hydroxyethyl) ammonium, triethyl (2-hydroxyethyl) ammonium, tripropyl (2-hydroxy) Ethyl) ammonium, tri-n-butyl (2-hydroxyethyl) ammonium, trimethylbenzylammonium, triethylbenzylammonium , Tripropylbenzylammonium, tri-n-butylbenzylammonium, trimethylphenylammonium, triethylphenylammonium, trimethyl-2-oxyethylammonium, monomethyltrihydroxyethylammonium, monoethyltrihydroxyethylammonium, okdadecyltri (2-hydroxy And hydroxides such as ethyl) ammonium and tetrakis (hydroxyethyl) ammonium.
Examples of the quaternary ammonium compound include hydrates other than halogenated compounds such as hydrogen azide; sulfuric acid, nitric acid, phosphoric acid, carbonic acid, boric acid, chloric acid, iodic acid, silicic acid, perchloric acid, Oxo acid salts such as 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, pentanoic acid, Examples thereof include carboxylates such as caproic acid, caprylic acid, capric acid, benzoic acid and oxalic acid. Among these, hydroxide (OH ⁻ ), sulfuric acid (HSO ₄ ⁻ , SO ₄ ²⁻ ), carbonic acid (HCO ₃ ⁻ , CO ₃ ²⁻ ), boric acid (B (OH) ₄ ⁻ ), and carboxylic acid Of these carboxylic acids, formic acid, acetic acid, and propionic acid are more preferable.
These quaternary ammonium compounds may be used alone or in combination of two or more.

The addition amount of the quaternary ammonium compound is 0.05 mass ppm or more and 50 mass ppm or less in terms of the amount of nitrogen derived from the quaternary ammonium compound represented by the following formula (A) with respect to the total amount of the copolymer. It is preferable that
P × 14 / Q (A)
In the formula (A), P represents a concentration (mass ppm) with respect to the copolymer of the quaternary ammonium compound, “14” represents the atomic weight of nitrogen, and Q represents the molecular weight of the quaternary ammonium compound.

  The quaternary ammonium compound may be added in advance before the copolymer is melted, or may be added to the melted crude polymer. In the present embodiment, ammonia, triethylamine, a boric acid compound or the like, which is a known decomposition / removal agent, and a quaternary ammonium compound may be used in combination.

(Hindered amine substances)
Since the polyacetal resin composition used for the polyacetal resin molded product of the present embodiment tends to be able to maintain the excellent appearance of the molded product, it is preferable that the polyacetal resin composition further includes a hindered amine material.
The content of the hindered amine-based substance is preferably 0.20 parts by mass or more and 2.0 parts by mass or less, more preferably 0.25 based on 100 parts by mass of the polyacetal resin contained in the polyacetal resin composition of the present embodiment. It is not less than 1.5 parts by mass and more preferably not less than 0.30 parts by mass and not more than 1.2 parts by mass.
By setting it as such a range, it exists in the tendency for the polyacetal resin molded product of this embodiment to maintain the further outstanding external appearance.
Only one kind of hindered amine material may be used alone, or two or more kinds may be used in combination.
The hindered amine-based substance preferably includes, for example, a substance having a piperidine derivative structure represented by the following general formula (4).

In formula (4), X represents a hydrogen atom, a hydroxyl group, an alkyl group, or an acyl group.
R _{1 to} R ₄ each independently represents an alkyl group.
Among these, a hindered amine material represented by the following general formula (5), in which X represents a hydrogen atom, is more preferable. By having this structure, it tends to be possible to maintain high stability during production.

In formula (5), R < ₁ > -R < ₄ > is synonymous with what is shown by General formula (4).
The hindered amine-based substance represented by the general formula (5) is not limited to the following, but examples thereof include 4-acetoxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2, 2,6,6-tetramethylpiperidine, 4-acryloyloxy-2,2,6,6-tetramethylpiperidine, 4- (phenylacetoxy) -2,2,6,6-tetramethylpiperidine 4-benzoyloxy- Examples include 2,2,6,6-tetramethylpiperidine, 4-methoxy-2,2,6,6-tetramethylpiperidine, and 4-stearyloxy-2,2,6,6-tetramethylpiperidine.
In addition, 4-cyclohexyloxy-2,2,6,6-tetramethylpiperidine, 4-benzyloxy-2,2,6,6-tetramethylpiperidine, 4-phenoxy-2,2,6,6-tetramethyl Piperidine, 4- (ethylcarbamoyloxy) -2,2,6,6-tetramethylpiperidine, 4- (cyclohexylcarbamoyloxy) -2,2,6,6-tetramethylpiperidine, 4- (phenylcarbamoyloxy)- 2,2,6,6-tetramethylpiperidine, bis (2,2,6,6-tetramethyl-4-piperidine) -carbonate, 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-piperi Le) - sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) - adipate, and bis (2,2,6,6-tetramethyl-4-piperidyl) - terephthalate may be mentioned.
In addition, 1,2-bis (2,2,6,6-tetramethyl-4-piperidyloxy) -ethane, α, α′-bis (2,2,6,6-tetramethyl-4-piperidyloxy) -P-xylene, bis (2,2,6,6-tetramethyl-4-piperidyl) tolylene-2,4-dicarbamate, bis (2,2,6,6-tetramethyl-4-piperidyl) -hexa Methylene-1,6-dicarbamate, tris (2,2,6,6-tetramethyl-4-piperidyl) -benzene-1,3,5-tricarboxylate, and tris (2,2,6,6- Mention may also be made of tetramethyl-4-piperidyl) -benzene-1,3,4-tricarboxylate.
Of these, bis (2,2,6,6-tetramethyl-4-piperidyl) -sebacate is preferred.

(Formaldehyde inhibitor)
The polyacetal resin composition used for the polyacetal resin molded article of this embodiment is one or more formaldehydes selected from the group consisting of aminotriazine compounds, guanamine compounds, urea compounds, and carboxylic acid hydrazide compounds. It is preferable to further contain an inhibitor.
Moreover, it is preferable that content of a formaldehyde inhibitor is 0.005 mass part or more and 5.0 mass parts or less with respect to 100 mass parts of polyacetal resins.

  Examples of the aminotriazine-based compound include, but are not limited to, for example, melamine; melamine condensates such as melam, melem, and melon; melamine resins such as melamine formaldehyde resin; N, N ′, N ″ -mono, Examples thereof include N-hydroxyarylalkyl melamine compounds such as bis, tris, tetrakis, pentakis, or hexakis (o-, m- or p-hydroxyphenylmethyl) melamine.

Examples of guanamine compounds include, but are not limited to, for example, aliphatic guanamine compounds such as valerologamine, caproguanamine, heptanoguanamine, capriloganamin, stealoganaamine; succinoguanamine, glutaro Alkylene bisguanamines such as guanamine, adipogguanamine, pimeloganamin, speroguanamine, azeroguanamine, sebacoguanamine; fats such as cyclohexanecarboguanamine, norbornenecarboguanamine, cyclohexenecarboguanamine, norbornanecarboguanamine and their functional group substituted derivatives Cyclic guanamine compounds; aromatic guanamine compounds such as benzoguanamine, α- or β-naphthoguanamine and their functional group-substituted derivatives; Polyguanamines such as namin, terephthaloguanamine, naphthalenediguanamine, biphenylenediguanamine; aralkyl or aralkyleneguanamines such as phenylacetoguanamine, β-phenylpropioguanamine, o-, m- or p-xylylenebisguanamine; Examples include heteroatom-containing guanamine compounds such as acetal group-containing guanamines, dioxane ring-containing guanamines, tetraoxospiro ring-containing guanamines, and isocyanuric ring-containing guanamines.
The functional group-substituted derivative in the alicyclic guanamine-based compound is not limited to the following, for example, alkyl group, hydroxy group, amino group, acetamino group, nitrile group, carboxy group, alkoxycarbonyl group, carbamoyl group , Derivatives in which 1 to 3 functional groups such as alkoxy group, phenyl group, cumyl group, and hydroxyphenyl group are substituted with cycloalkane residues.
In addition, the functional group-substituted derivative in the aromatic guanamine compound is not limited to the following, and examples thereof include an alkyl group, a hydroxy group, an amino group, an acetamino group, a nitrile group, a carboxy group, an alkoxycarbonyl group, and a carbamoyl group. Group, an alkoxy group, a phenyl group, a cumyl group, a hydroxyphenyl group or the like, and a derivative in which 1 to 5 functional groups are substituted with a phenyl residue of benzoguanamine or a naphthyl residue of naphthoguanamine. More specifically, o -, M- or p-toruguanamine, o-, m- or p-xyloganamine, o-, m- or p-phenylbenzoguanamine, o-, m- or p-hydroxybenzoguanamine, 4- (4'-hydroxy Phenyl) benzoguanamine, o-, m- or p-nitrile benzoguanamine, 3,5- Examples include dimethyl-4-hydroxybenzoguanamine and 3,5-di-t-butyl-4-hydroxybenzoguanamine.
Examples of the acetal group-containing guanamines include, but are not limited to, for example, 2,4-diamino-6- (3,3-dimethoxypropyl-s-triazine, and examples of the dioxane ring-containing guanamine include Although not limited to the following, for example, [2- (4′-6′-diamino-s-triazin-2′-yl) ethyl] -1,3-dioxane, and [2- (4′- 6'-diamino-s-triazin-2'-yl) ethyl] -4-ethyl-4-hydroxymethyl-1,3-dioxane, and tetraoxospiro ring-containing guanamines are limited to the following. Although it is not a thing, For example, CTU-guanamine and CMTU-guanamine are mentioned, Although it is not limited to the following as an isocyanuric ring containing guanamine, 1,3,5-tris [2- (4 ′, 6′-diamino-s-triazin-2′-yl) ethyl] isocyanurate and 1,3,5-tris [3- (4 ′, 6 '-Diamino-s-triazin-2'-yl) ethyl] isocyanurate.

The urea compound is not particularly limited, and examples thereof include a chain urea compound and a cyclic urea compound.
Examples of the chain urea compounds include, but are not limited to, condensates of urea and formaldehyde such as biurea, biuret, and form nitrogen, and polyalkylene or arylene urea such as polynanomethylene urea. It is done.
Examples of cyclic urea compounds include, but are not limited to, for example, hydantoins, clotylidene diurea, acetylene urea, mono, di, tri, or tetramethoxymethylene glycoluril, and other mono, di, tri, or tetraalkoxy Examples include methyl glycoluril, cyanuric acid, isocyanuric acid, urea, and urazole.
Examples of hydantoins include, but are not limited to, hydantoin, 5-methylhydantoin, 5-ethylhydantoin, 5-isopropylhydantoin, 5-phenylhydantoin, 5-benzylhydantoin, and 5,5-dimethylhydantoin. 5,5-pentamethylenehydantoin, 5-methyl-5-phenylhydantoin, 5,5-diphenylhydantoin, 5- (o-, m- or p-aminophenyl) hydantoin, allantoin, 5-methylallantoin, and allantoin Examples thereof include metal salts such as allantoin Al salt such as dihydroxyaluminum salt.

Examples of the carboxylic acid hydrazide compound include, but are not limited to, aliphatic carboxylic acid hydrazide compounds, alicyclic carboxylic acid hydrazide compounds, and aromatic carboxylic acid hydrazide compounds.
Examples of the aliphatic carboxylic acid hydrazide compound include, but are not limited to, for example, lauric acid hydrazide, stearic acid hydrazide, 12-hydroxystearic acid hydrazide, 1,2,3,4-butanetetracarboxylic acid hydrazide. Monocarboxylic acid hydrazides such as: succinic acid mono or dihydrazide, glutaric acid mono or dihydrazide, adipic acid mono or dihydrazide, pimelic acid mono or dihydrazide, suberic acid mono or dihydrazide, azelaic acid mono or dihydrazide, sebacic acid mono or dihydrazide, Polycarboxylic acid hydrazides such as dodecanedioic acid mono or dihydrazide, hexadecanedioic acid mono or dihydrazide, eicosanedioic acid mono or dihydrazide, 7,11-octadecadien-1,18-dicarbohydrazide And the like.
Examples of the alicyclic carboxylic acid hydrazide compounds include, but are not limited to, monocarboxylic acid hydrazides such as cyclohexanecarboxylic acid hydrazide; dimer acid mono or dihydrazide, trimer acid mono, di or trihydrazide, Carboxylic acid hydrazides such as 1,2-, 1,3- or 1,4-cyclohexanedicarboxylic acid mono- or dihydrazide, cyclohexanetricarboxylic acid mono-, di- or trihydrazide may be mentioned.
Examples of aromatic carboxylic acid hydrazide compounds include, but are not limited to, monobenzoic acid hydrazide and functional group-substituted derivatives thereof, α- or β-naphthoic acid hydrazide and functional group-substituted derivatives thereof, and the like. Carboxylic acid hydrazides; isophthalic acid mono- or dihydrazide, 1,4- or 2,6-naphthalenedicarboxylic acid mono- or dihydrazide, 3,3-, 3,4- or 4,4-diphenylcarboxylic acid mono- or dihydrazide, diphenyl ether dicarboxylic acid Acid mono or dihydrazide, diphenylmethane dicarboxylic acid mono or dihydrazide, diphenylethane dicarboxylic acid mono or dihydrazide, diphenoxyethane dicarboxylic acid mono or dihydrazide, diphenyl sulfone dicarboxylic acid mono or dihydrazide, diphenyl ketone dical Boronic acid mono or dihydrazide, 4,4 ″ -terphenyl dicarboxylic acid mono or dihydrazide, 4,4 ′ ″-quaterphenyl dicarboxylic acid mono or dihydrazide, 1,2,4-benzenetricarboxylic acid mono, di or trihydrazide And polycarboxylic acid hydrazides such as pyromellitic acid mono, di, tri or tetrahydrazide, 1,4,5,8-naphthoic acid mono, di, tri or tetrahydrazide.
The benzoic acid hydrazide and functional group-substituted derivatives thereof are not limited to the following, but examples include o-, m- or p-methylbenzoic acid hydrazide, 2,4-, 3,4-, 3,5. -Or 2,5-dimethylbenzoic acid hydrazide, o-, m- or p-hydroxybenzoic acid hydrazide, o-, m- or p-acetoxybenzoic acid hydrazide, 4-hydroxy-3-phenylbenzoic acid hydrazide, 4- Acetoxy-3-phenylbenzoic acid hydrazide, 4-phenylbenzoic acid hydrazide, 4- (4′-phenyl) benzoic acid hydrazide, 4-hydroxy-3,5-dimethylbenzoic acid hydrazide, 4-hydroxy-3,5-di -Alkyl group such as t-butylbenzoic acid hydrazide, hydroxy group, acetoxy group, amino group, acetamino group, nitrile group, carboxyl Examples thereof include derivatives in which 1 to 5 functional groups such as cis group, alkoxycarbonyl group, carbamoyl group, alkoxy group, phenyl group, benzyl group, cumyl group, and hydroxyphenyl group are substituted on the phenyl residue of benzoguanamine.
Examples of α- or β-naphthoic acid hydrazide and functional group-substituted derivatives thereof include, but are not limited to, for example, 3-hydroxy-2-naphthoic acid hydrazide and 6-hydroxy-2-naphthoic acid hydrazide. Is mentioned.

  The formaldehyde inhibitor is supported in a layered material or a porous material (hydrotalcite, montmorillonite, silica gel, alumina, titania, zirconia, sepiolite, smectite, palygorskite, imogolite, zeolite, activated carbon, etc.). Use is also possible.

  Among the above formaldehyde inhibitors, aminotriazine compounds, guanamine compounds, particularly aromatic guanamine compounds; urea compounds, particularly cyclic urea compounds; carboxylic acid hydrazide compounds, particularly aliphatic carboxylic acid hydrazide compounds, and aromatic carboxylic acids. Acid hydrazide compounds are preferably used. Among these, aliphatic carboxylic acid hydrazide compounds and aromatic carboxylic acid hydrazide compounds are more preferable. Among the aliphatic carboxylic acid hydrazide compounds and aromatic carboxylic acid hydrazide compounds, dihydrazides such as adipic acid dihydrazide, sebacic acid dihydrazide, dodecadic acid dihydrazide, isophthalic acid dihydrazide, and terephthalic acid dihydrazide are effective in suppressing the formation of formaldehyde. From the viewpoint of

  In the polyacetal resin used in the polyacetal resin molded product of the present embodiment, the content of the formaldehyde inhibitor is preferably 0.005 parts by mass or more and 5.0 parts by mass or less, more preferably 0 with respect to 100 parts by mass of the polyacetal resin. 0.01 parts by mass or more and 3.0 parts by mass or less, and more preferably 0.02 parts by mass or more and 2.0 parts by mass or less.

(Polyalkylene glycol)
It is preferable that the polyacetal resin composition used for the polyacetal resin molded article of the present embodiment further contains polyalkylene glycol. The content is preferably 0.3 parts by weight or more and 3.0 parts by weight or less, and 0.5 parts by weight or more and 2.0 parts by weight or less with respect to 100 parts by weight of the polyacetal resin. Is more preferably 0.7 parts by mass or more and 1.5 parts by mass or less. By setting it as such a range, it exists in the tendency which can improve production stability and can improve toughness more.
The polyalkylene glycol may be a copolymer or two or more types of polyalkylene glycols.
The polyalkylene glycol is preferably polyethylene glycol in terms of economy and handling.
The polyethylene glycol preferably has a number average molecular weight of 800 or more and 500000 or less, more preferably a number average molecular weight of 1000 or more and 20000 or less, and further preferably a number average molecular weight of 2000 or more and 10,000 or less. By setting it within this range, the toughness and brightness tend to be further improved.
The number average molecular weight of polyethylene glycol can be measured using, for example, a magnetic resonance spectrometer. Specifically, it can be measured as follows. First, polyethylene glycol to be measured is dissolved in a solvent: HFIP-d ₂ (D conversion rate 97%, Wako Pure Chemicals 98% assay) over 24 hours to prepare a 1.5% by mass resin solution. Next, for the resin solution, using an apparatus: JEOL-400 nuclear magnetic resonance spectrometer ( ¹ H: 400 MHz), temperature: 55 ° C., integration number: 500 times, integration of oxyethylene component and hydroxyl group attribution peaks The number average molecular weight is determined from the amount of the oxyethylene component relative to the terminal hydroxyl group.

(Hydrazide compound)
The polyacetal resin composition used for the polyacetal resin molded article of the present embodiment preferably further contains a hydrazide compound in order to further improve the production stability.
The content of the hydrazide compound is preferably 0.03 parts by mass or more and 0.25 parts by mass or less, and 0.05 parts by mass or more and 0.20 parts by mass or less with respect to 100 parts by mass of the polyacetal resin. Is more preferably 0.07 parts by mass or more and 0.15 parts by mass or less.
The hydrazide compound may be added during granulation of the polyacetal resin, added during the production of the polyacetal resin composition, or both.
The hydrazide compound is not limited to the following, but for example, dicarboxylic acid dihydrazide represented by the following general formula (6) is preferable, and malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, pimelin Acid dihydrazide, speric acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, isophthalic acid dihydrazide, and phthalic acid dihydrazide are preferred.
^{_{H 2 NHNOC-R 1 -CONHNH 2}} ··· (6)
In said formula (6), R < ¹ > shows a C2-C20 hydrocarbon.
Among the dicarboxylic acid dihydrazides, preferred are sebacic acid dihydrazide, dodecanedioic acid dihydrazide, isophthalic acid dihydrazide, and adipic acid dihydrazide, and more preferred are sebacic acid dihydrazide and adipic acid dihydrazide.
Only one type of hydrazide compound may be contained alone, or two or more types may be used in combination.

(Coloring agent)
The polyacetal resin composition of the present embodiment can further contain a colorant in order to enhance design properties.
Examples of the colorant include, but are not limited to, a bright material, an organic pigment, an inorganic pigment, and a dye.
Moreover, a colorant may be used individually by 1 type and may be used in combination of 2 or more type.

The bright material is not particularly limited as long as it reflects light and improves the brightness of the polyacetal resin molded product. Examples of the bright material include metal pigments, metal-coated glass, and mica, and metal pigments are preferable. The shape of the metal pigment is not particularly limited, but it is more preferably a coin shape or flake shape.
The “coin shape” is a shape called a disk shape or a disk shape, and indicates a shape in which the surface of the particle is high and the edge portion of the particle is smooth. Coin-like metal pigments tend to provide molded articles with relatively high brightness. On the other hand, the term “flakes” refers to a shape called corn flakes or scales, and the surface smoothness of the particles is lower than that of coins and the edges of the particles are jagged. .
In the metal pigment, the average particle thickness t (average shape ratio: average particle thickness t / average particle size D) with respect to the average particle size D is preferably 0.6 or less, more preferably 0.4 or less. More preferably, it is 0.2 or less.
By making the shape of the metal pigment within this range, good dispersibility is obtained when the metal pigment is melt-mixed with the polyacetal resin, and the appearance tends to be improved efficiently with a smaller addition amount. In addition, the metal pigment is preferably one having a smooth surface and no cracks in the peripheral portion because the particles are not easily damaged during kneading with the polyacetal resin.

The average particle thickness t of the metal pigment can be determined, for example, by the following method.
After washing the metal pigment with acetone and drying it, the mass w (g) was measured, and the coating area S (cm ² ) when this was evenly floated on the water surface was measured, and the WCA (water surface diffusion coating area; S / w) was calculated. Derived and calculated by substituting into the following formula (B).
Average particle thickness t (μm) = 4000 / (S / w) (B)
The average particle diameter D of the metal pigment is a value (D ₅₀ ) that is 50% of the particle diameter distribution measured by a laser diffraction particle size distribution analyzer.
The average particle diameter (D ₅₀ ) of the metal pigment is preferably in the range of 3.0 μm to 80 μm, more preferably in the range of 4.0 μm to 50 μm, and in the range of 4.0 μm to 40 μm. More preferably it is. When the average particle diameter of the metal pigment is in such a range, the production stability during granulation can be further maintained, and the resin composition can retain the toughness that is the mechanical property inherent in the polyacetal resin. There is a tendency.
The average particle thickness t of the metal pigment is not particularly limited, but is preferably in the range of 0.05 μm to 1.0 μm, and more preferably in the range of 0.08 μm to 0.8 μm. preferable. By using a metal pigment having an average particle thickness t in such a range, when kneading with a polyacetal resin, the particles are not easily damaged, the balance between physical properties of strength and toughness is maintained, and the weld appearance of the molded body is further improved. It tends to be good.
Further, depending on the combination, the physical property balance between strength and toughness can be improved, so two or more kinds of metal pigments may be used.

  The bright material generally has a particle size distribution having a certain width, and the average particle size indicates a peak value. Moreover, it is preferable that the particle size distribution of the metal pigment used for the polyacetal resin molded product of this embodiment has a plurality of peaks having different particle sizes. Such a metal pigment can be obtained by using a plurality of types of metal pigments having different average particle diameters in combination. By having a plurality of peaks with different particle size distributions, it tends to be possible to obtain a polyacetal resin molded article having a good balance between brightness and granularity, which is a measure of a design surface having metallic luster. .

The organic pigment is not particularly limited, and examples thereof include phthalocyanine pigments, condensed azo pigments, azo lake pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments, and condensed polycyclic pigments.
Examples of inorganic pigments include, but are not limited to, simple oxides such as zinc white, titanium dioxide, petal, chromium oxide, and iron black; sulfides such as cadmium yellow, cadmium orange, and cadmium red; yellow lead, zinc yellow And chromate such as chromium vermilion, ferrocyanide such as bitumen; silicate such as ultramarine; inorganic colorants such as carbon black and metal powder.

  The content of the colorant is not particularly limited, but it improves the appearance of the polyacetal resin molded product of the present embodiment, suppresses the decrease in strength, and suppresses the amount of formaldehyde generated as measured by the VDA method, the VOC method, and the like. Therefore, the amount is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and still more preferably 3 parts by mass or less with respect to 100 parts by mass of the polyacetal resin.

(Other additives)
The polyacetal resin composition used for the polyacetal resin molded article of the present embodiment may further contain other additives other than those described above.
Examples of other additives include heat stabilizers used in conventional polyacetal resins.
Examples of the heat stabilizer include, but are not limited to, antioxidants, formaldehyde and formic acid scavengers, and the like.
A heat stabilizer may be used individually by 1 type, and may use 2 or more types together.

Although it does not specifically limit as antioxidant, A hindered phenolic antioxidant is preferable.
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-t-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) -propyl It is a Pioneto). Tetrakis- (methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate methane, 3,9-bis (2- (3- (3-t-butyl) -4-hydroxy-5-methylphenyl) propionyloxy) -1,1-dimethylethyl) 2,4,8,10-tetraoxaspiro (5,5) undecane, N, N'-bis-3- (3 '5'-di-t-butyl-4-hydroxyphenol) priionyl hexamethylenediamine, N, N'-tetramethylenebis-3- (3'-methyl-5'-t-butyl-4-hydroxyphenol) ) Propionyldiamine, N, N′-bis- (3- (3,5-di-tert-butyl-4-hydroxyphenol) propionyl) hydrazine, N-salicyloyl-N′-salicylidenehydrazine, 3- (N - Tyrosyl) amino-1,2,4-triazole, and N, N′-bis (2- (3- (3,5-di-butyl-4-hydroxyphenyl) propionyloxy) ethyl) oxyamide. .
Among the hindered phenol antioxidants, triethylene glycol-bis- (3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) -propionate) and tetrakis- (methylene-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate methane is preferred.

The scavenger for formaldehyde and formic acid is not particularly limited. For example, (b) compounds and polymers containing formaldehyde-reactive nitrogen, (b) alkali metal or alkaline earth metal hydroxides, inorganic acid salts, carvone Examples include acid salts and alkoxides.
(I) Compounds containing formaldehyde-reactive nitrogen include, but are not limited to, (1) dicyandiamide, (2) amino-substituted triazines, and (3) co-condensates of amino-substituted triazines and formaldehyde. .
(2) The amino-substituted triazine is not limited to the following, but includes, for example, guanamine (2,4-diamino-sym-triazine), melamine (2,4,6-triamino-sym-triazine), N -Butylmelamine, N-phenylmelamine, N, N-diphenylmelamine, N, N-diallylmelamine, N, N ', N "-triphenylmelamine, N-methylolmelamine, N, N'-dimethylolmelamine, N, N ′, N ″ -trimethylolmelamine, and benzoguanamine (2,4-diamino-6-phenyl-sym-triazine). 2,4-diamino-6-methyl-sym-triazine, 2,4-diamino-6-butyl-sym-triazine, 2,4-diamino-6-benzyloxy-sym-triazine, 2,4-diamino -6-butoxy-sym-triazine, 2,4-diamino-6-cyclohexyl-sym-triazine, 2,4-diamino-6-chloro-sym-triazine, 2,4-diamino-6-mercapto-sym-triazine 2,4-dioxy-6-amino-sym-triazine (Amelite), 2-oxy-4,6-diamino-sym-triazine (Ameline), and N, N ′, N′-tetracyanoethylbenzoguanamine. .
(3) The co-condensate of amino-substituted triazine and formaldehyde is not limited to the following, and examples thereof include melamine-formaldehyde polycondensate.
Among these, dicyandiamide, melamine, and melamine-formaldehyde polycondensate are preferable.

(A) The polymer having a formaldehyde-reactive nitrogen group is not particularly limited. For example, (1) polyamide resin, (2) acrylamide and derivatives thereof, or acrylamide and derivatives thereof, and other vinyls A polymer obtained by polymerizing a monomer in the presence of a metal alcoholate; (3) a polymer obtained by polymerizing acrylamide and its derivatives, or acrylamide and its derivatives and other vinyl monomers in the presence of radical polymerization. And (4) polymers containing nitrogen groups such as amines, amides, ureas and urethanes.
The polyamide resin of (1) is not limited to the following, but, for example, nylon 4-6, nylon 6, nylon 6-6, nylon 6-10, nylon 6-12, nylon 12 and a combination thereof. Examples of the polymer include nylon 6 / 6-6, nylon 6 / 6-6 / 6-10, and nylon 6 / 6-12.
The polymer obtained by polymerizing acrylamide and its derivative of (2), or acrylamide and its derivative and another vinyl monomer in the presence of a metal alcoholate is not limited to the following. A poly-β-alanine copolymer may be mentioned. These polymers and copolymers are described in JP-B-6-12259 (corresponding to US Pat. No. 5,015,707), JP-B-5-87096, JP-B-5-47568, and JP-A-3-234729. It can manufacture by the method of each gazette of gazette.

In addition, when the polyacetal resin composition of the present embodiment is used as a material of a molded product used for a design part such as an interior or exterior part of an automobile, a benzotriazole type used in a conventional polyacetal resin and It is preferable to further contain an ultraviolet absorber selected from oxalic anilide-based ultraviolet absorbers.
Only one type of ultraviolet absorber may be used alone, or two or more types may be used in combination.
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′-di-isoamyl-phenyl) benzotriazole, 2- [2′-hydroxy-3 ′, 5 ′ -Bis-([alpha], [alpha] -dimethylbenzyl) phenyl] benzotriazole and 2- (2'-hydroxy-4'-octoxyphenyl) benzotriazole.
Examples of the oxalic anilide-based ultraviolet absorber include, but are not limited to, 2-ethoxy-2′-ethyloxalic acid bisanilide, 2-ethoxy-5-t-butyl-2′- Examples include ethyl oxalic acid bisanilide and 2-ethoxy-3′-dodecyl oxalic acid bisanilide.

  The polyacetal resin composition used in the polyacetal resin molded product of the present embodiment includes a lubricant, various inorganic fillers, other thermoplastic resins, softeners, crystals, and the like that are conventionally used in polyacetal resins within a range that does not impair the object of the present invention. A nucleating agent, a release agent and the like can be further included.

(Production method of polyacetal resin composition)
The polyacetal resin composition used for the polyacetal resin molded article of the present embodiment includes the above-described polyacetal resin and the above-described hindered amine-based materials, formaldehyde inhibitors, polyalkylene glycols, hydrazide compounds, colorants, and the like. It can manufacture by mixing an additive.
From the viewpoint of distribution from the manufacturer to the manufacturer, the polyacetal resin composition has a spherical or cylindrical shape called a pellet, and is processed into a granulated product (solid material) having a diameter of about 1 to several mm in cross-sectional shape. Is preferred.
This granulated product can be produced, for example, by using a melt kneader used for processing plastic materials.

In order to uniformly disperse the above-described additives and the like in the polyacetal resin, the powder obtained by pulverizing a part or the whole amount of the polyacetal resin pellets and the additive are mixed in advance, and then melt mixed. Good.
Moreover, when using a polyacetal resin pellet, you may improve dispersibility, such as an additive, using an additive.
Examples of the additive include, but are not limited to, for example, aliphatic hydrocarbons, aromatic hydrocarbons, modified products thereof, and mixtures thereof (liquid paraffin, mineral oil, etc.). Also included are fatty acid esters of polyols.

The production of the polyacetal resin composition used for the polyacetal resin molded article of the present embodiment is performed by melt-kneading polyacetal resin and additives such as hindered amine substances, formaldehyde inhibitors, polyalkylene glycols, hydrazide compounds, and colorants in advance. It can also be carried out by (pre-kneading).
For this pre-kneading, a generally used melt-kneader can be used.
Although it does not specifically limit as a melt-kneader, For example, a kneader, a roll mill, a single screw extruder, a twin screw extruder, and a multi-screw extruder are mentioned. The processing temperature at the time of pre-kneading is not particularly limited, but is preferably 180 to 230 ° C, more preferably 190 to 210 ° C.
In order to maintain the quality and working environment, and to suppress the occurrence of dust explosions, additives such as polyacetal resin pellets, hindered amine substances, formaldehyde inhibitors, polyalkylene glycols, hydrazide compounds, colorants, etc. Replace the single side or the container for mixing these, the container to be stored, the flow path between the container and the extruder, the hopper of the extruder, etc. with the inert gas upstream from the point where these mixtures melt And / or degassing with a single-stage or multistage vent.

  In the production process of the polyacetal resin composition used for the polyacetal resin molded product of the present embodiment, a lubricant, various inorganic fillers, and the like conventionally used in the polyacetal resin depending on desired properties within a range that does not impair the object of the present invention. These thermoplastic resins, softeners, crystal nucleating agents, mold release agents and the like may be further mixed.

Furthermore, when producing a polyacetal resin composition containing a bright material that is a colorant, it tends to be able to maintain high stability and productivity during production of the polyacetal resin composition. It is preferable to sufficiently dry the glitter material in advance before mixing with the glitter material.
The term “drying” as used herein means that a bright material having a mass W ₁ (g) before mixing is dried in an oven at 80 ° C. for 2 hours, and the mass W ₂ (g) after the drying is expressed by a relational expression [(W ₁ −W ₂ ) / W ₂ ] is to prepare the glitter material so that it is 0.0015 or less, and it is preferable to prepare it so that it is 0.001 or less.

(Manufacturing method of polyacetal resin molded product)
The polyacetal resin molded product of this embodiment can be produced by molding the polyacetal resin composition described above.
The molding method is not particularly limited. For example, in addition to a general injection molding method used for molding a thermoplastic resin into a desired shape, extrusion molding, foam molding, injection compression molding, two-color molding, insert Examples thereof include molding, outsert molding, blow molding, and gas assist molding using nitrogen gas or carbon dioxide gas.
These molding methods may be used alone or in combination of two or more.
The gas assist molding method is generally a known injection molding method using nitrogen gas or carbon dioxide gas. More specifically, as described in JP-B-57-14968, etc., resin A method of injecting a pressurized gas into a molded product after injecting the composition into the mold cavity, and a molded product after injecting the resin composition into the mold cavity as described in Japanese Patent No. 3819972 And a method of injecting a pressurized gas into a cavity corresponding to one side of the sheet, and a method of filling a thermoplastic resin with a gas in advance and molding as described in Japanese Patent No. 3349070.
These gas assist molding methods are appropriately selected depending on the molded product and the product shape. The gas assist molding method is preferably an injection molding / injection compression molding, or a molding method in which these are combined with in-mold composite molding from the viewpoints of quality, production stability, economy, and the like.
Furthermore, the manufacturing method of the molded product of the present embodiment includes bonding of a polyacetal resin composition and various resins including rubber and elastomer (ultrasonic bonding, high frequency bonding, hot plate bonding, hot press molding, multilayer injection molding, multilayer injection molding) Blow molding and other methods do not matter) By providing a molded product with two or more layers, it gives excellent performance (impact resistance, slidability, chemical resistance, etc.) of various resins, and is excellent It is possible to obtain a molded body having an appearance having a good design property.
Furthermore, it is also preferable to use a metal mold that is partially or entirely filled during molding.
The polyacetal resin molded product of the present embodiment is preferable because the adhesion effect between the polyacetal resin composition and the coating layer is improved by exhibiting an anchor effect when the surface is a textured surface.

Hereinafter, an example of the manufacturing method of the polyacetal resin molded product of the present embodiment will be specifically described with reference to FIGS.
In FIG. 1, the schematic perspective view of an example of the polyacetal resin molded product of this embodiment is shown.
First, as shown in FIG. 2, a prepared polyacetal copolymer (component A) is produced using a twin screw extruder.
The twin-screw extruder is composed of a front stage and a rear stage. A dry polyacetal resin and water are supplied at the front end of the front stage, and vacuum deaeration is performed at the rear end of the front stage.
A predetermined additive is supplied from the side feeder at the front end of the rear stage to obtain the intended prepared polyacetal copolymer (component A).
Then, as shown in FIG. 2, a polyacetal resin composition is manufactured using a twin screw extruder.
The twin-screw extruder is composed of a front stage and a rear stage. In the hopper at the front stage, the prepared polyacetal copolymer (component A), the additive component (component B) previously mixed with the pellets, and other additives are added. Then, vacuum deaeration is performed at the rear end of the front stage.
At the front end of the rear stage, an additive component (component C) is supplied from the side feeder to obtain the desired polyacetal resin composition.
Here, the additive component refers to additives such as heat stabilizers, colorants such as fillers and pigments, etc. In addition to additive components, side pellets of adjusted polyacetal copolymer are supplied It is also possible to do.
By using this polyacetal resin composition, the polyacetal resin molded product of this embodiment is obtained by molding by the molding method described above.

(Coat layer)
In the polyacetal resin molded product of this embodiment, at least a part of the molded product is covered with a coating layer having a thickness of 2 μm or more and 300 μm or less.
The coating layer has acid resistance, and has a high affinity with the polyacetal resin molded product before curing, is necessary and sufficient adhesion after curing, and is formed with a coating agent excellent in antiblocking properties It is preferable that
Here, “acid resistance” means that a molded article made of the polyacetal resin composition as a base material is not damaged after being contacted with hydrochloric acid having a concentration of 35% for 1 hour.
Moreover, it is preferable that it is a coat layer provided with functions other than acid resistance such as antistatic, ultraviolet or infrared opaque, water repellency, and antifouling as required.
Furthermore, the coat layer constituting the polyacetal resin molded product of the present embodiment is not limited to the one that covers the entire polyacetal resin molded product, but only necessary portions according to the use of the polyacetal resin molded product, for example, the entire surface layer or the surface layer It may cover a part of.

  Further, for the purpose of adjusting the viscosity of the coating liquid used for the coating layer, the coating liquid may be diluted with various organic solvents including petroleum hydrocarbons.

The method for curing the coating layer is not particularly limited, but in consideration of the fact that an easy curing process already used for existing products has been established, a curing method by light or a curing method by dehydration condensation can be mentioned. . By curing the coating film, a coating layer having excellent antiblocking properties can be obtained.
For example, when a photocurable composition is used as the material for the coating layer, the coating film can be photocured by irradiating it with energy rays. The energy beam used for photocuring is not particularly limited as long as the coating film is cured. For example, energy such as ultraviolet rays, far infrared rays, near ultraviolet rays, infrared rays, X rays, γ rays, electron rays, proton rays, neutron rays, etc. Lines can be used. Among these energy rays, curing by ultraviolet irradiation (hereinafter also simply referred to as “UV”) is preferable from the viewpoint that the curing speed is fast and the apparatus is easily available, and the coating layer is a cured product of a UV curable coating. Preferably there is.
The resin that is cured by UV is not limited to the following, but examples thereof include acrylic resins, epoxy resins, silicone resins, phenol resins, polyimide resins, polybenzoxazole resins, polyphenylene resins, and polyresins. Examples include benzocyclobutene resin, polyarylene ether resin, polycyclohexane resin, polyester resin, fluorine resin, polyolefin resin, polycycloolefin resin, cyanate resin, polyphenylene ether resin, polystyrene resin, etc. be able to. These may be used alone or in combination of two or more.
In order to form a coat layer having excellent transparency and wear resistance, it is preferable to use an acrylic silicone resin to which colloidal silica is added as a material for the coat layer.
Further, when a UV curable resin is used as the material of the coat layer, a photoinitiator (curing initiator) may be appropriately added according to each resin. What is necessary is just to add a photoinitiator about 1-10 mass% with respect to resin. At this time, the photoinitiator to be used is not particularly limited. Moreover, it is preferable to implement the process which dries the solvent component which a coating agent contains as a process before irradiating UV.
On the other hand, when a resin that cures by dehydration condensation is used as a material for forming the coat layer, the resin is not particularly limited, and examples thereof include organic siloxane compounds and silicone solvents that are liquid at room temperature. Specifically, it is preferably a silicone solvent containing an organic resin-modified silicone resin such as an epoxy resin, an alkyd resin, or a polyester resin, or a hydroxy-terminated dimethylsiloxane-treated silica, and the purpose of accelerating the curing thereof. Thus, a curing catalyst such as phosphoric acid, titanium, aluminum, amine, zinc, or iron may be mixed as necessary.
Among resins that are cured by dehydration condensation, there are resins that cure in a room temperature environment, but from the viewpoint of the production process, a resin that cures in a relatively short time by heat treatment in a high temperature environment is preferable. For example, a resin that cures under a heat treatment condition of about 2 hours in an 80 ° C. temperature environment is preferable.
As a silicone-based resin that is a material of these coat layers, by using a resin in which a polyfunctional resin and a low-functional resin (monofunctional to tetrafunctional resin) are appropriately mixed, both wear resistance and weather resistance are achieved. This is preferable. In this case, it is preferable to use a mixture of a polyfunctional resin and a low functional resin so that the average functional group number of the resin component in the resin composition is relatively low and bifunctional to tetrafunctional. By making the average functional group of the resin within the above range, it is possible to prevent the coating layer from cracking due to long-term outdoor use.

(Formation method of coat layer)
The method for applying the coating liquid for forming the coating layer is not limited, but examples thereof include a bar coating method, a flow coating method, a dip coating method, a spin coating method, a roll coating method, and a spray coating method. Ordinary wet coating methods such as a meniscus coating method, a gravure coating method, a suction coating method, and a brush coating method can be used.
Considering the required shape of the part, the flow coating method, the dip coating method, and the spray coating method are preferable.

(Coat layer thickness)
In the polyacetal resin molded product of this embodiment, at least a part of the polyacetal resin molded product is covered with a coating layer having a thickness of 2 μm to 300 μm.
The film thickness of the coat layer is 2 μm or more from the viewpoint of maintaining acid resistance ability, and is 300 μm or less from the viewpoint of curing time.
When the polyacetal resin molded product of this embodiment has a coat layer, acid resistance can be imparted to the polyacetal resin molded product.
The thickness of the coat layer is preferably 2 μm or more and 100 μm or less, and more preferably 2 μm or more and 50 μm or less.
Since the coating layer is thin, it can be cured with less energy, and the time required for curing is completed in a short time, which is preferable.
The method for measuring the thickness of the coat layer is not limited. For example, a lens such as VH-ZST is connected to a microscope, VHX-1000, 5000 series manufactured by Keyence Corporation, and the coat layer. Can be obtained by image analysis of a cross-section of a polyacetal resin molded product containing.
The method of adjusting the thickness of the coating layer is not limited, but for example, the method of adjusting the viscosity of the coating solution with an organic solvent, the number of bar coaters used in the bar coating method, or after dipping in the dip coating method The drawing speed can be adjusted as appropriate according to the spin coating time in the spin coating method, the processing time for spraying the coating liquid in the spray coating method, and the like.

The coat layer is preferably formed using a hard coat film-forming paint from the viewpoint of ensuring surface hardness.
Here, the hard coat film is a coat film formed on the surface layer of the base material, and is a coat film having a pencil hardness equal to or higher than that of the base material.
Examples of hard coat film forming paints include acrylic resins, epoxy resins, silicone resins, phenolic resins, polyimide resins, polybenzoxazole resins, polyphenylene resins, polybenzocyclobutene resins, and polyarylenes. Examples thereof include paints including ether resins, polycyclohexane resins, polyester resins, fluorine resins, polyolefin resins, polycycloolefin resins, cyanate resins, polyphenylene ether resins, polystyrene resins and the like.
The hard coat film is generally obtained by applying a hard coat film-forming paint on the surface of the molded article and then curing it with UV.

[Use]
The polyacetal resin molded product of the present embodiment can be used for mechanical parts, sliding parts, design parts, containers, and the like that are required to have acid resistance, and can also be suitably used for parts that combine these parts.
Specific polyacetal resin molded products include, for example, parts used for OA equipment, music, video or information equipment, communication equipment, industrial parts used for office furniture or residential equipment, and parts used for automobile interior and exterior Any of these parts is preferable.
Also, fuel tanks and peripheral devices that are automotive functional parts, wiper driving devices, window elevating devices, clips, housings, inner handles, shift knobs, steering and wheels, levers, switches, etc. , Buttons and other functional parts that require acid resistance, and decorative parts are also suitable.
Furthermore, depending on the parts for which appearance characteristics are required, it may be a molded product with a textured mold because it may impart design properties using a textured mold partially or entirely during molding. Is also preferable.

Hereinafter, the present embodiment will be specifically described with reference to examples and comparative examples, but the present embodiment is not limited to the following examples.
In addition, the acquisition method of the raw material in an Example and a comparative example is as follows.

〔Base material〕
As the base material, polyacetal copolymer resin “Tenac ^™ (registered trademark) -C4520 (commercially available)” manufactured by Asahi Kasei Co., Ltd., “EC75S” injection molding machine manufactured by Toshiba Machine Co., Ltd., length 120 mm, width Using a mold for injection molding capable of producing a flat test piece having a thickness of 80 mm and a thickness of 2 mm, a flat test piece was manufactured under the molding temperature conditions of a cylinder temperature of 200 ° C. and a mold temperature of 80 ° C.

[Coating solution]
Details of the coating liquids a, b, c, d, and e used in Examples and Comparative Examples are shown below.
Coating liquid a: Hard coating liquid “APC-100A” manufactured by Dainichi Seika Kogyo Co., Ltd.
Coating solution b: Silicon dispersion “PRX 308 Dispersion Clear” manufactured by Toray Dow Corning Co., Ltd.
Coating liquid c: 50 parts by mass of room temperature curable organic resin-modified silicone resin “ES-1002T” manufactured by Shin-Etsu Chemical Co., Ltd., 5 parts by mass of the company-made amine-based catalyst “KP-390”, Kanto Chemical ( Co., Ltd. (reagent) xylene 10 parts by mass, Kanto Chemical Co., Ltd. (reagent) diacetone alcohol 15 parts by mass, Kanto Chemical Co., Ltd. (reagent) methyl ethyl ketone 20 parts by mass (total 100 masses) Part).
Coating solution d: Polycarbonate diol “Duranol T5650J” manufactured by Asahi Kasei Co., Ltd. and (reagent) butyl acetate manufactured by Kanto Chemical Co., Ltd. in a mass ratio of polycarbonate diol: butyl acetate = 37.5: 62.5 What mixed 19.4 mass parts of hexamethylene isocyanate "TKA-100" made by the company with 100 mass parts of mixed liquid.
Coating liquid e: Asahi Kasei Co., Ltd. polycarbonate diol “Duranol T4671” and Kanto Chemical Co., Ltd. (reagent) butyl acetate at a mass ratio of polycarbonate diol: butyl acetate = 37.5: 62.5 What mixed 14.3 mass parts Hexamethylene isocyanate "TPA-100" made in the company with 100 mass parts of mixed liquid.

[Coating solution coating method]
The coating solution was applied by dipping a flat test piece into the coating solution.

[Curing liquid curing method]
The coating liquid a was dip-coated and then dried for about 2 minutes in a drier set at 80 ° C., and then cured by UV irradiation. At this time, the UV illuminance (integrated light amount) was about 600 to 700 mJ / cm ² .
The coating liquids b and c were dip-coated and then dehydrated and condensed by drying for 2 hours in a drier set at 80 ° C. to cure the coating layer.
Since the coating liquids d and e had low affinity with the surface layer of the test piece made of polyacetal resin, a uniform coat film could not be formed by the dip coating method, so no further evaluation was performed.

  The characteristic of the polyacetal resin molded product which has a coating layer of Examples 1-4 and Comparative Examples 1-3 was measured by the method shown below.

[Coat layer thickness]
The thickness of the coating layer was measured by image analysis of the cross section of the polyacetal resin molded product including the coating layer using a combination of a microscope, VHX-5000 and a lens, VH-ZST, manufactured by Keyence Corporation.

[Adhesion]
A cutter mark was formed by cutting with a cutter so as to reach the base material made of the polyacetal resin from the coat layer of the polyacetal resin molded product having the coat layer.
At that time, “○” indicates that the coating layer is not peeled around the cutter marks, and “△” indicates that the coating layer is slightly peeled around the cutter marks. When it was recognized, it was set as “x”.

[Acid resistance]
3 mL of 35% hydrochloric acid was dropped with a dropper on the upper surface of a test piece (flat plate product) placed horizontally in a draft and left standing.
After 1 hour, wash the hydrochloric acid on the flat plate with running water, and after drying, check for the presence or absence of corrosion marks due to hydrochloric acid. If no corrosion marks are found, “◯”; When corrosion marks were observed, “x” was assigned.

  Table 4 shows the composition of the coating liquid, the coating method, the curing method, and the thickness of the coating layer in the polyacetal resin molded articles of Examples 1 to 4 and Comparative Examples 1 to 3.

〔result〕
In Examples 1 to 4, the thickness of the coating layer was 2 μm to 300 μm, the adhesion between the coating layer and the polyacetal resin was good, and the acid resistance was excellent.

  The polyacetal resin molded product of the present invention is a mechanical part, sliding part, design part, container, etc., a combination of these parts, OA equipment, music, video or information equipment, parts used for communication equipment, office furniture or housing. Industrial parts used for installation equipment, and parts used inside and outside of automobiles, for example, fuel tanks and peripheral devices that are functional parts for automobiles, wiper driving devices, window lifting devices, clips, housings, There are industrial applicability as interior parts, shift knobs, steering wheels, steering wheels, levers, switches, buttons, and other functional parts that require acid resistance, as well as decorative parts, which are interior and exterior parts of automobiles. .

Claims (4)

A polyacetal resin molded article comprising a polyacetal resin composition,
At least a part is covered with a coating layer having a thickness of 2 μm or more and 300 μm or less,
Polyacetal resin molded product.   The polyacetal resin molded product according to claim 1, wherein the coating layer has a thickness of 2 μm or more and 100 μm or less.   The polyacetal resin molded product according to claim 1 or 2, wherein the coat layer is a cured product of an ultraviolet curable paint.   The polyacetal resin molded product according to any one of claims 1 to 3, wherein the coat layer is a coat layer made of a hard coat film forming paint.