JP2015052028A - Method for producing polyacetal resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polyacetal resin composition capable of producing a polyacetal resin composition in which the process variation in the generation amount of formaldehyde is reduced.SOLUTION: There is provided a method for producing a polyacetal resin composition which comprises 100 pts.mass of a polyacetal resin (A), 0.01 to 0.5 pt.mass of a formaldehyde inhibitor (B), 0.01 to 5 pts.mass of a colorant (C) and 0.01 to 0.5 pt.mass of an impregnating agent (D), the method comprising: a step of mixing the polyacetal resin (A) and the impregnating agent (D) to impregnate the impregnating agent (D) to the surface of the (C); a step of adding and mixing the formaldehyde inhibitor (B); a step of adding and mixing the colorant (D); and a step of extruding and kneading the resulting mixture by an extruder.

Description

  The present invention relates to a method for producing a polyacetal resin composition.

  Polyacetal resin has excellent balance of mechanical strength, chemical resistance and slidability and is easy to process. Therefore, as typical engineering plastics, electrical equipment, mechanical parts of the electrical equipment, automotive parts , And other mechanical parts.

In recent years, especially in the field of automobile interior parts, there has been an increasing demand for reducing the amount of volatile organic compounds (VOC) containing formaldehyde, and materials with added formaldehyde inhibitors are being studied.
For example, in Patent Document 1 below, a polyacetal resin, a colorant, a formaldehyde inhibitor, other additives, and liquid paraffin as an additive are mixed by a tumbler type blender, and then melt kneaded by an extruder. A proposed composition has been proposed.

JP 2010-84140 A

  However, according to the technique described in Patent Document 1, when the amount of the formaldehyde inhibitor used is large, the process fluctuation of the formaldehyde generation amount, that is, the fluctuation of the formaldehyde generation amount with time is small and good. On the other hand, when the amount of formaldehyde inhibitor used is reduced, there is a problem that the process variation increases. This is because the formaldehyde inhibitor is unevenly distributed in the composition.

  In view of the above-described problems of the prior art, an object of the present invention is to provide a method for producing a polyacetal resin composition in which the process variation is small even when the amount of formaldehyde inhibitor used is small.

As a result of intensive studies to solve the above problems, the present inventors have found a polyacetal resin composition containing (A) a polyacetal resin, (B) a formaldehyde inhibitor, (C) a colorant, and (D) an additive. By specifying the mixing order of these materials in the manufacturing method, it has been found that the above-mentioned problems of the prior art can be solved, and the present invention has been completed.
That is, the present invention is as follows.

[1]
(A) polyacetal resin: 100 parts by mass;
(B) Formaldehyde inhibitor: 0.01 to 0.5 parts by mass;
(C) Colorant: 0.01 to 5 parts by mass;
(D) Additive: 0.01 to 0.5 parts by mass;
A process for producing a polyacetal resin composition comprising:
Mixing the (A) polyacetal resin and the (D) additive, and impregnating the (D) additive on the surface of the (A);
Then, (B) adding and mixing the formaldehyde inhibitor,
Thereafter, the step of adding and mixing the colorant (C), the step of extrusion kneading with an extruder,
The manufacturing method of the polyacetal resin composition which has these.
[2]
The (B) formaldehyde inhibitor is an aliphatic carboxylic acid hydrazide compound and / or an aromatic carboxylic acid hydrazide compound,
The method for producing a polyacetal resin composition according to [1], wherein the content of the (B) formaldehyde inhibitor is 0.01 to 0.3 parts by mass.
[3]
The (B) formaldehyde inhibitor is at least one selected from the group consisting of adipic acid dihydrazide, sebacic acid dihydrazide, dodecadioic acid dihydrazide, isophthalic acid dihydrazide and terephthalic acid dihydrazide,
The method for producing a polyacetal resin composition according to [1] or [2], wherein the content of the (B) formaldehyde inhibitor is 0.02 to 0.3 parts by mass.
[4]
The method for producing a polyacetal resin composition according to any one of [1] to [3], wherein the (A) polyacetal resin has an amount of formaldehyde measured by VDA275 of 20 mg / kg or less.

  According to the method for producing a polyacetal resin composition of the present invention, it is possible to produce a polyacetal resin composition in which process fluctuations in the amount of formaldehyde generated are reduced.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

The production method of the polyacetal resin composition of the present embodiment,
(A) polyacetal resin: 100 parts by mass;
(B) Formaldehyde inhibitor: 0.01 to 0.5 parts by mass;
(C) Colorant: 0.01 to 5 parts by mass;
(D) Additive: 0.01 to 0.5 parts by mass;
A process for producing a polyacetal resin composition comprising:
Mixing the (A) polyacetal resin and the (D) additive, and impregnating the surface of the (A) polyacetal resin with the (D) additive;
Then, (B) adding and mixing the formaldehyde inhibitor,
Thereafter, (C) adding and mixing the colorant;
A process of extrusion kneading with an extruder;
Have

  First, components used in the method for producing the polyacetal resin composition of the present embodiment will be described below.

((A) polyacetal resin)
As the (A) polyacetal resin used in this embodiment (in this specification, (A) component, may be described as (A)), a formaldehyde monomer or a trimer thereof (trioxane) or 4 amounts Formaldehyde cyclic oligomers such as tetraoxane, ethylene oxide, propylene oxide, epichlorohydrin, glycols such as 1,3-dioxolane and 1,4-butanediol formal, and cyclic ethers such as cyclic formal of diglycol, and cyclic formal A typical example is a polyacetal copolymer obtained by copolymerization of
Moreover, the polyacetal copolymer which has a branch obtained by copolymerizing monofunctional glycidyl ether, and the polyacetal copolymer which has a crosslinked structure obtained by copolymerizing polyfunctional glycidyl ether can also be used.
Furthermore, a compound having a functional group such as a hydroxyl group at both ends or one end, for example, a polyacetal polymer having a block component obtained by polymerizing a formaldehyde monomer or a cyclic oligomer of formaldehyde in the presence of polyalkylene glycol, Similarly, a compound having a functional group such as a hydroxyl group at both ends or one end, for example, a cyclic formaldehyde such as formaldehyde monomer or trimer (trioxane) or tetramer (tetraoxane) in the presence of hydrogenated polybutadiene glycol. A polyacetal copolymer having a block component obtained by copolymerizing an oligomer with cyclic ether or cyclic formal can also be used.

  The comonomer such as 1,3-dioxolane used in the production of (A) polyacetal resin used in the present embodiment is generally 0.001 to 0.2 mol, preferably 0.005 to 0, per 1 mol of trioxane. 0.1 mol, more preferably 0.01 to 0.07 mol.

  (A) From the viewpoint of mechanical properties, the melting point of the polyacetal resin is preferably 155 ° C to 173 ° C, more preferably 160 ° C to 171 ° C.

(A) The polymerization of a polyacetal resin can apply a well-known catalyst as a polymerization catalyst. In particular, cationically active catalysts such as Lewis acids, proton acids and esters or anhydrides thereof are preferred.
Examples of the Lewis acid include, but are not limited to, boric acid, tin, titanium, phosphorus, arsenic, and antimony halides. Specific examples include boron trifluoride and tin tetrachloride. , Titanium tetrachloride, phosphorus pentafluoride, phosphorus pentachloride, antimony pentafluoride, and complex compounds or salts thereof.
Further, the protonic acid and its ester or anhydride are not limited to the following, but examples include perchloric acid, trifluoromethanesulfonic acid, perchloric acid-tertiary butyl ester, acetyl perchlorate, trimethyloxonium. Examples include hexafluorophosphate.
Among these, (A) polyacetal resin polymerization catalyst includes boron trifluoride; boron trifluoride hydrate; and a coordination complex compound of an organic compound containing oxygen atom or sulfur atom and boron trifluoride. Preferable examples include boron trifluoride diethyl ether and boron trifluoride di-n-butyl ether.

The (A) polyacetal resin used in this embodiment preferably has a residual fluorine concentration of 13 ppm or less, and more preferably 8 ppm or less.
The (A) polyacetal resin having a residual fluorine concentration of 13 ppm or less can be obtained by a method in which the concentration of the polymerization catalyst at the time of polymerization is set to a certain concentration or less.
Specifically, the polymerization catalyst concentration is preferably 3.0 × 10 ⁻⁵ mol or less with respect to 1 mol of trioxane.
In particular, in order to obtain the (A) polyacetal resin having a residual fluorine concentration of 8 ppm or less, the polymerization catalyst concentration is preferably 1.5 × 10 ⁻⁵ mol or less with respect to 1 mol of trioxane.
In addition, when the concentration of the polymerization catalyst during polymerization is high and the fluorine concentration remaining in the (A) polyacetal resin exceeds 13 ppm, the residual fluorine in the (A) polyacetal resin is removed by washing with a predetermined solvent. The concentration can be 13 ppm or less.
Specifically, a so-called terminal stabilization treatment is performed in which the unstable terminal portion contained in the polyacetal resin after the polymerization catalyst is deactivated immediately after polymerization or the polyacetal resin in which the polymerization catalyst is deactivated is decomposed into a stable terminal. A method of washing the polyacetal resin and the like after passing at a high temperature with warm water, water vapor, a mixed solvent of water and an organic solvent, or the like can be mentioned.
For example, by treating the polyacetal resin after terminal stabilization treatment in an aqueous solution containing 15% methanol at a temperature of 80 ° C. to 150 ° C. for 10 minutes to several hours, the residual fluorine concentration in the polyacetal resin is reduced to 13 ppm or less. can do. The cleaning treatment conditions can be variously adjusted according to the residual fluorine concentration in the polyacetal resin before the cleaning treatment.

(A) As a polymerization method of polyacetal resin, generally it can carry out by bulk polymerization, and both a batch type and a continuous type are possible.
As the polymerization apparatus, a self-cleaning type extrusion kneader such as a kneader, a twin-screw continuous extrusion kneader, or a twin-screw paddle type continuous mixing machine can be used, and the molten monomer is supplied to the polymerization machine. As the polymerization proceeds, a solid mass (A) polyacetal resin can be obtained.

Since the polyacetal resin obtained by polymerization has a thermally unstable terminal portion [-(OCH ₂ ) _n —OH group], it is known as a specific indicator of low formaldehyde generation amount as it is. It is difficult to satisfy the condition that “formaldehyde generation amount when heated at 200 ° C. for 50 minutes in a nitrogen atmosphere is 100 ppm or less”.
Therefore, as will be described later, it is preferable to perform the decomposition removal treatment of the unstable end portion.
In the presence of at least one quaternary ammonium compound represented by the following general formula (1), the decomposition and removal treatment of the unstable terminal portion of the polyacetal resin is performed at a temperature not lower than the melting point of the polyacetal resin and not higher than 260 ° C. It heat-processes in the state which melted the polyacetal resin.
[R ₁ R ₂ R ₃ R ₄ N ⁺ ] _n X ⁻ⁿ (1)
(In the general formula _{(1), R 1, R} 2, R 3, 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 An aralkyl group in which an unsubstituted alkyl group having 1 to 30 carbon atoms or a substituted alkyl group is substituted with at least one aryl group having 6 to 20 carbon atoms; or an aryl group having 6 to 20 carbon atoms having at least one carbon The alkylaryl group substituted by the unsubstituted alkyl group of 1-30, or the substituted alkyl group is shown, and an unsubstituted alkyl group or a substituted alkyl group is linear, branched, or cyclic. The substituent is a halogen group, a hydroxyl group, an aldehyde group, a carboxyl group, an amino group, or an amide group.
In the unsubstituted alkyl group, aryl group, aralkyl group, and alkylaryl group, a hydrogen atom 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 other than hydrogen halide, an oxo acid, an inorganic thio acid, or an organic thio acid having 1 to 20 carbon atoms. )

Among these, R ₁ , R ₂ , R ₃ , and R ₄ in the general formula (1) are each independently an alkyl group having 1 to 5 carbon atoms or a hydroxyalkyl group having 2 to 4 carbon atoms. And at least one of R ₁ , R ₂ , R ₃ , and R ₄ is more preferably a hydroxyethyl group.
Examples of the quaternary ammonium compound represented by the general formula (1) include, but are not limited to, tetramethylammonium, tetoethylammonium, 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-hydroxyethyl) ammonium, tri-n-butyl (2-hydroxyethyl) ammonium, trimethylbenzylammonium, tri Tilbenzylammonium, tripropylbenzylammonium, tri-n-butylbenzylammonium, trimethylphenylammonium, triethylphenylammonium, trimethyl-2-oxyethylammonium, monomethyltrihydroxyethylammonium, monoethyltrihydroxyethylammonium, okdadecyltri ( Hydroxides such as 2-hydroxyethyl) ammonium and tetrakis (hydroxyethyl) ammonium; Hydrochloric acid salts such as hydrochloric acid, odorous acid and hydrofluoric acid; sulfuric acid, nitric acid, phosphoric acid, carbonic acid, boric acid, chloric acid, iodine acid Oxo acid salts such as silicic acid, 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, pentanoic acid, Prong acid, caprylic acid, capric acid, benzoic acid, carboxylic acid salts such as oxalic acid.
Among the above, hydroxide (OH ⁻ ), sulfuric acid (HSO ₄ ⁻ , SO ₄ ²⁻ ), carbonic acid (HCO ₃ ⁻ , CO ₃ ²⁻ ), boric acid (B (OH) ₄ ⁻ ), carboxylic acid Salts are preferred.
Of the carboxylic acids, formic acid, acetic acid, and propionic acid are more preferable.
The quaternary ammonium compounds described above may be used alone or in combination of two or more.

The addition amount of the quaternary ammonium compound in the decomposition and removal treatment of the unstable terminal portion of the polyacetal resin is a quaternary ammonium compound represented by the following formula (2) with respect to the total mass of the polyacetal resin and the quaternary ammonium compound. In terms of the amount of nitrogen derived from, it is preferably 0.05 to 50 ppm by mass, more preferably 1 to 30 ppm by mass.
P × 14 / Q (2)
(In the formula (2), P represents the amount (ppm) of the quaternary ammonium compound relative to the total mass of the polyacetal resin and the quaternary ammonium compound, 14 is the atomic weight of nitrogen, and Q is the quaternary ammonium. Indicates the molecular weight of the compound.)
If the addition amount of the quaternary ammonium compound is less than 0.05 ppm by mass, the decomposition and removal rate of the unstable end tends to decrease. If it exceeds 50 ppm by mass, the polyacetal copolymer after the decomposition and removal of the unstable end is removed. The color tone tends to deteriorate.

Moreover, it is preferable to perform the decomposition removal process of the unstable terminal part of the said polyacetal resin using an extruder, a kneader, etc. at the resin temperature of more than melting | fusing point of a polyacetal resin and 260 degrees C or less.
When the processing temperature exceeds 260 ° C., there may be a problem of coloring and a problem of decomposition (reduction in molecular weight) of the polymer main chain.

  It is preferable to remove formaldehyde generated by the above-described decomposition and removal treatment of the unstable terminal portion of the polyacetal resin under reduced pressure.

The addition method of the quaternary ammonium compound in the decomposition and removal treatment of the unstable terminal portion of the polyacetal resin is not particularly limited, and is a method of adding it as an aqueous solution in the step of deactivating the polymerization catalyst, and spraying the resin powder. Methods and the like.
Whichever addition method is used, it is sufficient that the polyacetal resin is added in the step of decomposing and removing the unstable end portion of the polyacetal resin, and the polyacetal resin may be injected into the extruder, the extruder, etc. In the case of blending fillers and pigments using quaternary, a quaternary ammonium compound may be attached to the pellets of polyacetal resin, and the decomposition and removal treatment of unstable ends may be performed in the subsequent blending step of fillers and pigments.

The decomposition and removal treatment of the unstable terminal of the polyacetal resin can be performed after deactivating the polymerization catalyst in the polyacetal resin obtained by polymerization, or can be performed without deactivating the polymerization catalyst. It is.
A typical example of the deactivation of the polymerization catalyst is a method of neutralizing and deactivating the polymerization catalyst in a basic aqueous solution such as amines.
In addition, without deactivation of the polymerization catalyst, the unstable terminal may be decomposed and removed after heating in an inert gas atmosphere at a temperature below the melting point of the polyacetal resin to reduce the volatilization of the polymerization catalyst. .

(Thermal stabilizer, weathering agent)
In the manufacturing method of the polyacetal resin composition of this embodiment, you may add the heat stabilizer and weathering agent which are used for the conventional polyacetal resin.
Thermal stabilizers include antioxidants, formaldehyde or formic acid scavengers, and combinations thereof.

The antioxidant is preferably a hindered phenol-based antioxidant, and is not limited to the following. For example, 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) - propionate) and the like.
Examples of other hindered phenol antioxidants include, but are not limited to, tetrakis- (methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxy). Phenyl) 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) propionylhexamethylenediamine, N, N′-tetra Methylenebis-3- (3′-methyl-5′-t-butyl-4-hydroxyphenol) propionyldiamine, N, N′-bis- (3- (3,5-di-t-butyl-4-hydroxy) Fenault L) propionyl) hydrazine, N-salicyloyl-N′-salicylidenehydrazine, 3- (N-salicyloyl) amino-1,2,4-triazole, N, N′-bis (2- (3- (3 5-di-butyl-4-hydroxyphenyl) propionyloxy) ethyl) oxyamide.
Among these hindered phenolic antioxidants, triethylene glycol-bis- (3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) -propionate) and tetrakis are used from the viewpoint of performance and cost. -(Methylene-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate methane is preferred.

  Examples of the formaldehyde or formic acid scavenger include, but are not limited to, compounds and polymers containing formaldehyde-reactive nitrogen, fatty acid calcium salts, hydroxides of alkali metals or alkaline earth metals, An inorganic acid salt, a carboxylate salt or an alkoxide is mentioned.

Examples of the compound containing formaldehyde-reactive nitrogen include, but are not limited to, dicyandiamide, amino-substituted triazine, and a co-condensate of amino-substituted triazine and formaldehyde.
Examples of the amino-substituted triazine include, but are not limited to, guanamine (2,4-diamino-sym-triazine), melamine (2,4,6-triamino-sym-triazine), and N-butyl. Melamine, N-phenylmelamine, N, N-diphenylmelamine, N, N-diallylmelamine, N, N ′, N ″ -triphenylmelamine, N-methylolmelamine, N, N′-dimethylolmelamine, N, N ′, N ″ -trimethylolmelamine, benzoguanamine (2,4-diamino-6-phenyl-sym-triazine) can be mentioned. 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), N, N ′, N′-tetracyanoethylbenzoguanamine.
Examples of the co-condensate of amino-substituted triazine and formaldehyde include, but are not limited to, melamine-formaldehyde polycondensate.
Of these, dicyandiamide, melamine and melamine-formaldehyde polycondensate are preferred.
The polymer having formaldehyde-reactive nitrogen is not limited to the following, for example, polyamide resin, acrylamide and derivatives thereof, or acrylamide and derivatives thereof and other vinyl monomers in the presence of metal alcoholate. Polymers obtained by polymerization, acrylamide and derivatives thereof, or polymers obtained by polymerizing acrylamide and derivatives thereof and other vinyl monomers in the presence of radical polymerization, nitrogen atoms such as amines, amides, ureas and urethanes The polymer which has is mentioned.
Examples of the polyamide resin include, but are not limited to, nylon 4-6, nylon 6, nylon 6-6, nylon 6-10, nylon 6-12, nylon 12, and copolymers thereof. Examples thereof include nylon 6 / 6-6, nylon 6 / 6-6 / 6-10, and nylon 6 / 6-12.
The polymer obtained by polymerizing acrylamide and its derivatives or acrylamide and its derivatives and other vinyl monomers in the presence of a metal alcoholate is not limited to the following, for example, poly-β- An alanine copolymer is mentioned. These polymers and copolymers are described in JP-B-6-12259 (US Pat. No. 5,015,707), JP-B-5-87096, JP-B-5-47568 and JP-A-3-234729. It can be produced by the method described in each document.

Examples of the fatty acid calcium salt include, but are not limited to, calcium salts of saturated or unsaturated fatty acids having 10 to 36 carbon atoms, and may be substituted with a hydroxyl group.
Examples of the saturated fatty acid include, but are not limited to, for example, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, montanic acid, melicic acid And celloplastic acid.
Examples of the unsaturated fatty acids include, but are not limited to, for example, undecylenic acid, oleic acid, elaidic acid, cetreic acid, erucic acid, brassic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, priol Examples include acids and stearol acids. Among these fatty acids, palmitic acid, stearic acid, and 12-hydroxystearic acid are particularly preferable.
In the manufacturing method of the polyacetal resin composition of this embodiment, the addition amount of the said fatty acid calcium salt shall be 0.01-0.5 mass part with respect to 100 mass parts of (A) polyacetal resin. More preferably, it is 0.02-0.3 mass part. By making the addition amount of the fatty acid calcium salt 0.01 to 0.5 parts by mass, the thermal stability during the molding process is improved, the amount of formaldehyde generated from the molded body is reduced, and the heat aging resistance is improved. It will be better.

Examples of the alkali metal or alkaline earth metal hydroxide, inorganic acid salt, carboxylate or alkoxide include, but are not limited to, for example, hydroxide such as sodium, potassium, magnesium, calcium, or barium. And carbonates, phosphates, silicates, borates, and carboxylates of the above metals. However, the above fatty acid calcium salt is excluded.
Examples of the carboxylic acid corresponding to the carboxylate include, but are not limited to, for example, saturated or unsaturated aliphatic carboxylic acids having 10 to 36 carbon atoms, and these carboxylic acids are It may be substituted with a hydroxyl group.
Examples of the saturated aliphatic carboxylic acid include, but are not limited to, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, and montanic acid. , Melicic acid and celloplastic acid.
Examples of the unsaturated aliphatic carboxylic acid include, but are not limited to, undecylenic acid, oleic acid, elaidic acid, celetic acid, erucic acid, brassic acid, sorbic acid, linoleic acid, linolenic acid, and arachidone. Examples include acids, propiolic acid, and stearic acid.
Examples of the alkoxide include methoxide and ethoxide of the above metals.

As the weathering agent, a hindered amine stabilizer and an ultraviolet absorber are used.
Examples of the hindered amine stabilizer include piperidine derivatives having a sterically hindered group. Although not limited to the following, for example, an ester group-containing piperidine derivative, an ether group-containing piperidine derivative, and an amide group-containing piperidine derivative may be mentioned. By including a hindered amine stabilizer, the polyacetal resin composition obtained by the production method of the present embodiment is particularly excellent in fluidity, mechanical properties such as impact resistance of the molded article, and weather resistance (light stability). It will be excellent.

Examples of the ester group-containing piperidine derivatives include, but are not limited to, aliphatic acyloxypiperidines, aromatic acyloxypiperidines, aliphatic di- or tricarboxylic acid-bis or tripiperidyl esters, and aromatic di-, tri- Or tetracarboxylic acid-bis, tris or tetraxpiperidyl ester.
Examples of the aliphatic acyloxypiperidine include, but are not limited to, 4-acetoxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-tetra C2-20 aliphatic acyloxy-tetramethylpiperidine such as methylpiperidine, 4-acryloyloxy-2,2,6,6-tetramethylpiperidine.
Examples of the aromatic acyloxypiperidine include, but are not limited to, C7-11 aromatic acyloxytetramethylpiperidine such as 4-benzoyloxy-2,2,6,6-tetramethylpiperidine. .
Examples of the aliphatic di- or tricarboxylic acid-bis or tripiperidyl ester include, but are not limited to, bis (2,2,6,6-tetramethyl-4-piperidyl) oxalate and bis (2 , 2,6,6-tetramethyl-4-piperidyl) malonate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5-bis (1,1-dimethylethyl)- 4-hydroxyphenyl] methyl] butyl malonate, bis (2,2,6,6-tetramethyl-4-piperidyl) adipate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) adipate, Bis (1-methyl-2,2,6,6-tetramethyl-4-piperidyl) adipate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl sepacate, bis (2) decanedioate (2 , 2,6,6-tetramethyl-1- (octyloxy) -4-piperidinyl) ester and the like C2-20 aliphatic dicarboxylic acid-bispiperidyl ester.
Examples of the aromatic di-, tri-, or tetracarboxylic acid-bis, tris, or tetrakispiperidyl ester include, but are not limited to, for example, bis (2,2,6,6-tetramethyl-4-piperidyl) Aromatic di- or tricarboxylic acid-bis or tripiperidyl esters such as terephthalate, tris (2,2,6,6-tetramethyl-4-piperidyl) benzene-1,3,5-tricarboxylate.
In addition to these, tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate is also exemplified as the ester group-containing biperidine derivative.

  In the present specification, “Ca-b” means that the carbon number is a to b (a and b are integers), for example, “C 2-20” has 2 to 20 carbon atoms. Means that.

Examples of the ether group-containing piperidine derivatives include, but are not limited to, C1-10 alkoxypiperidine, C5-8 cycloalkyloxypiperidine, C6-10 aryloxypiperidine, C6-10 aryl-C1-4. Examples thereof include alkyloxypiperidine and alkylenedioxybispiperidine.
Examples of the C1-10 alkoxypiperidine include, but are not limited to, C1-6 alkoxy-tetramethylpiperidine such as 4-methoxy-2,2,6,6-tetramethylpiperidine, Examples of the C5-8 cycloalkyloxypiperidine include, but are not limited to, 4-cyclohexyloxy-2,2,6,6-tetramethylpiperidine.
Examples of the C6-10 aryloxypiperidine include, but are not limited to, 4-phenoxy-2,2,6,6-tetramethylpiperidine, and the C6-10 aryl-C1-4. Examples of the alkyloxypiperidine include, but are not limited to, 4-benzyloxy-2,2,6,6-tetramethylpiperidine, and the alkylenedioxybispiperidine is limited to the following. Although not mentioned, for example, C1-10 alkylenedioxybispiperidine such as 1,2-bis (2,2,6,6-tetramethyl-4-piperidyloxy) ethane can be mentioned.

  Examples of the amide group-containing piperidine derivatives include, but are not limited to, carbamoyloxypiperidine such as 4- (phenylcarbamoyloxy) -2,2,6,6-tetramethylpiperidine, bis (2, And carbamoyloxy-substituted alkylenedioxy-bispiperidine such as 2,6,6-tetramethyl-4-piperidyl) hexamethylene-1,6-dicarbamate.

In addition to the above, the hindered amine stabilizer is not limited to the following. For example, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-succinate Tetramethylpiperidine polycondensate, 1,2,3,4-butanetetracarboxylic acid, 1,2,2,6,6-pentamethyl-4-piperidinol and tridecyl alcohol, and 1,2,2, 3,4-butanetetracarboxylic acid, 1,2,2,6,6-pentamethyl-4-piperidinol and β, β, β ′, β′-tetramethyl-3,9- (2,4,8,10 High molecular weight piperidine derivative polycondensates such as a condensate with -tetraoxaspiro [5,5] undecane) -diethanol can also be used.
In addition to the above, the hindered amine stabilizer is not limited to the following. For example, 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, 1- [2- {3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy} ethyl] -4- {3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy} -2 , 2,6,6-tetramethylpiperidine, and peroxidized 4-butylamino-2,2,6,6-tetramethylpiperidine and 2,4,6-trichloro-1,3,5-triazine Reaction product of cyclohexane with cyclohexane And product, N, N'-1,2-diyl bis (the 1,3-propane diamine), include the reaction product of.

The above-mentioned hindered amine stabilizers may be used alone or in combination of two or more.
In the manufacturing method of the polyacetal resin composition of this embodiment, the addition amount of the hindered amine stabilizer mentioned above is 0.01-5 mass parts with respect to 100 mass parts of (A) polyacetal resin, Preferably it is 0.00. It is 1-2 mass parts, More preferably, it is 0.1-1.5 mass parts. By adjusting the addition amount of the hindered amine stabilizer within this range, the molded article of the polyacetal resin composition obtained by the production method of the present embodiment can maintain an excellent appearance.

(UV absorber)
The polyacetal resin composition obtained by the production method of the present embodiment preferably further contains an ultraviolet absorber. Thereby, in the molded object obtained from a polyacetal resin composition, the improvement of a weather resistance (light stability) can be aimed at.
Examples of the ultraviolet absorber include, but are not limited to, benzotriazole compounds, benzophenone compounds, oxalic acid anilide compounds, and hydroxyphenyl-1,3,5-triazine compounds.

Examples of the benzotriazole-based compound include, but are not limited to, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole and 2- (2′-hydroxy-3 ′, 5 ′). -Di-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-amylphenyl) benzotriazole, 2- (2'-hydroxy-3', 5'-di Benzotriazoles having a hydroxyl group and an alkyl group (preferably a C1-6 alkyl group) substituted aryl group such as isoamylphenyl) benzotriazole; 2- [2′-hydroxy-3 ′, 5′-bis (α, α -Dimethylbenzyl) phenyl] benzotriazoles having a hydroxyl group and an aralkyl group or an aryl group-substituted aryl group such as benzotriazole; 2- (2 ′ -Hydroxy-4'-octoxyphenyl) benzotriazoles having a hydroxyl group and an alkoxy group (preferably a C1-12 alkoxy group) substituted aryl group.
Among the benzotriazole compounds, preferably, a benzotriazole having a hydroxyl group and a C3-6 alkyl group-substituted C6-10 aryl group (particularly a phenyl group), and a hydroxyl group and a C6-10 aryl-C1-6 Benzotriazoles having an alkyl group (particularly a phenyl C1-4 alkyl group) and a substituted aryl group.
Examples of the benzophenone compounds include, but are not limited to, benzophenones having a plurality of hydroxyl groups; benzophenones having a hydroxyl group and an alkoxy group (preferably a C1-16 alkoxy group). .
Examples of the benzophenones having a plurality of hydroxyl groups include, but are not limited to, di-, tri- or tetrahydroxybenzophenones such as 2,4-dihydroxybenzophenone; 2-hydroxy-4-benzyloxybenzophenone, etc. And benzophenones having a hydroxyl group and a hydroxyl-substituted aryl or aralkyl group.
The benzophenones having a hydroxyl group and an alkoxy group are not limited to the following, and examples thereof include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy Examples include -4-dodecyloxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, and 2-hydroxy-4-methoxy-5-sulfobenzophenone.
Preferred benzophenone compounds include benzophenones having a hydroxyl group and a hydroxyl group-substituted C6-10 aryl group or a C6-10 aryl-C1-4 alkyl group, particularly a hydroxyl group and a hydroxyl group-substituted phenyl C1-2 alkyl group. Benzophenones.

  Examples of the oxalic acid anilide compound include, but are not limited to, N- (2-ethylphenyl) -N ′-(2-ethoxy-5-tert-butylphenyl) oxalic acid diamide, N -(2-Ethylphenyl) -N '-(2-ethoxy-phenyl) oxalic acid diamide.

  Examples of the hydroxyphenyl-1,3,5-triazine compound include, but are not limited to, for example, 2,4-diphenyl-6- (2-hydroxyphenyl) -1,3,5-triazine. 2,4-diphenyl-6- (2,4-dihydroxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5 -Triazine, 2,4-diphenyl-6- (2-hydroxy-4-ethoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-propoxyphenyl) -1 , 3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy- -Hexyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-octyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6 (2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine.

Among the hindered amine stabilizers and UV absorbers described above as weathering agents, hindered amine stabilizers include bis (2,2,6,6-tetramethyl-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 A condensate with ', β'-tetramethyl-3,9- (2,4,8,10-tetraoxabis [5,5'] undecane) diethanol is more preferable. A compound is more preferable, and 2- [2′-hydroxy-3 ′, 5′-bis (α, α-dimethylbenzyl) phenyl] benzotriazole is more preferable.
In the method for producing a polyacetal resin composition of the present embodiment, when an ultraviolet absorber and a hindered amine stabilizer are added, the ratio of the hindered amine stabilizer to the ultraviolet absorber is as follows: hindered amine stabilizer / ultraviolet absorber (mass Ratio) is preferably 10/90 to 80/20, more preferably 10/90 to 70/30, and still more preferably 20/80 to 60/40. The addition amount of these weathering agents is preferably 0.1 to 2 parts by mass, more preferably 0.2 to 1 part by mass, and still more preferably 0.2 to 100 parts by mass of the (A) polyacetal resin. -1 part by mass.

((A) Properties of polyacetal resin)
The (A) polyacetal resin used in this embodiment preferably has an amount of formaldehyde measured by VDA275 of 20 mg / kg or less. When the amount of formaldehyde is 20 mg / kg or less, it is possible to reduce the amount of formaldehyde generated by using a small amount of formaldehyde inhibitor, and an economic effect is obtained.
The formaldehyde content is more preferably 15 mg / kg or less, and further preferably 10 mg / kg or less.
The amount of formaldehyde by VDA275 can be measured by the method described in the examples described later.

((B) Formaldehyde inhibitor)
In the method for producing the polyacetal resin composition of the present embodiment, (B) a formaldehyde inhibitor (hereinafter, may be referred to as (B) component or (B)) is used.
A formaldehyde inhibitor is a compound having formaldehyde scavenging performance.
Examples of (B) formaldehyde inhibitors include, but are not limited to, aminotriazine compounds, guanamine compounds, urea compounds, and hydrazine compounds.
These (B) formaldehyde inhibitors may be used alone or in combination of two or more.

Examples of the aminotriazine-based compounds 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 ″ — Examples include N-hydroxyarylalkyl melamine compounds such as mono, bis, tris, tetrakis, pentakis, or hexakis (o-, m- or p-hydroxyphenylmethyl) melamine.
Examples of the guanamine-based compound include, but are not limited to, for example, aliphatic guanamine-based compounds such as valerologamine, caproguanamine, heptanoguanamine, capriloganamin, stealoganamine; succinoguanamine, glucan Alkylenebisguanamines such as tagoguanamine, adipogguanamine, pimeloganamin, suboguanamine, azeroguanamine, sebacoguanamine; cyclohexanecarboguanamine, norbornenecarboguanamine, cyclohexenecarboguanamine, norbornanecarboguanamine, and functional group substituted derivatives thereof Alicyclic guanamine-based compounds of the above; aromatic guanamine-based compounds such as benzoguanamine, α- or β-naphthoguanamine and their functional group-substituted derivatives; Polyguanamines such as softaloganamine, terephthaloguanamine, naphthalenediguanamine, biphenylene diguanamine; aralkyl or aralkyleneguanamine such as phenylacetoguanamine, β-phenylpropioguanamine, o-, m- or p-xylylenebisguanamine 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 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. And derivatives in which 1 to 3 functional groups such as a group, an alkoxy group, a phenyl group, a cumyl group, and a hydroxyphenyl group are substituted with a cycloalkane residue.
The functional group-substituted derivative in the aromatic guanamine-based compound is not limited to the following, for example, an alkyl group, a hydroxy group, an amino group, an acetamino group, a nitrile group, a carboxy group, an alkoxycarbonyl group, Derivatives in which 1 to 5 functional groups such as a carbamoyl group, an alkoxy group, a phenyl group, a cumyl group, and a hydroxyphenyl group are substituted with a phenyl residue of benzoguanamine or a naphthyl residue of naphthoguanamine are exemplified. -Or p-toruguanamine, o-, m- or p-xyloganamine, o-, m- or p-phenylbenzoguanamine, o-, m- or p-hydroxybenzoguanamine, 4- (4'-hydroxyphenyl) benzoguanamine O-, m- or p-nitrile benzoguanamine, 3,5-di Examples include methyl-4-hydroxybenzoguanamine and 3,5-di-t-butyl-4-hydroxybenzoguanamine.
Examples of the acetal group-containing guanamines include, but are not limited to, 2,4-diamino-6- (3,3-dimethoxypropyl-s-triazine.
Examples of the dioxane ring-containing guanamines include, but are not limited to, for example, [2- (4′-6′-diamino-s-triazin-2′-yl) ethyl] -1,3-dioxane. , [2- (4′-6′-diamino-s-triazin-2′-yl) ethyl] -4-ethyl-4-hydroxymethyl-1,3-dioxane.
Examples of the tetraoxospiro ring-containing guanamines include, but are not limited to, CTU-guanamine and CMTU-guanamine.
Examples of the isocyanuric ring-containing guanamines include, but are not limited to, for example, 1,3,5-tris [2- (4 ′, 6′-diamino-s-triazin-2′-yl) ethyl. Isocyanurate, 1,3,5-tris [3- (4 ′, 6′-diamino-s-triazin-2′-yl) propyl] isocyanurate.
Examples of the urea compound include, but are not limited to, a chain urea compound and a cyclic urea compound. Specific examples of the chain urea compound include, but are not limited to, for example, condensates of urea and formaldehyde such as biurea, biuret, and form nitrogen, and polyalkylene such as polynonamethylene urea, Arylene urea is mentioned. Specific examples of the cyclic urea compound include, but are not limited to, for example, hydantoins, clothylidene diurea, acetylene urea, mono, di, tri or tetramethoxymethyl glycoluril such as tetramethoxymethyl glycoluril. Examples include tri- or tetraalkoxymethyl glycoluril, cyanuric acid, isocyanuric acid, uric acid, and urazole. Examples of the hydantoins include, but are not limited to, hydantoin, 5-methylhydantoin, 5-ethylhydantoin, 5-isopropylhydantoin, 5-phenylhydantoin, 5-benzylhydantoin, and 5,5-dimethyl. Hydantoin, 5,5-pentamethylenehydantoin, 5-methyl-5-phenylhydantoin, 5,5-diphenylhydantoin, 5- (o-, m- or p-hydroxyphenyl) hydantoin, 5- (o-, m- Or p-aminophenyl) hydantoin, allantoin, 5-methylallantoin, and metal salts such as Al salts of allantoin such as allantoin dihydroxyaluminum salts.

Examples of the hydrazine-based compound include carboxylic acid hydrazide-based compounds. Examples of the carboxylic acid hydrazide-based compounds include, but are not limited to, aliphatic carboxylic acid hydrazide-based compounds and alicyclic carboxylic acids. Examples thereof include 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. Monocarboxylic acid hydrazides such as hydrazide; 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 hydrides such as dodecanedioic acid mono- or dihydrazide, hexadecanedioic acid mono- or dihydrazide, eicosanedioic acid mono- or dihydrazide, 7,11-octadecadien-1,18-dicarbohydrazide, etc. Hydrazide compounds, 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 1, 2-, 1,3- or 1,4-cyclohexanedicarboxylic acid mono or dihydrazide, cyclocarboxylic acid trihydric acid mono, di or trihydrazide and other polycarboxylic acid hydrazides.
Examples of the aromatic carboxylic acid hydrazide compound include, but are not limited to, for example, benzoic acid hydrazide and functional group-substituted derivatives thereof, α- or β-naphthoic acid hydrazide, and functional group-substituted derivatives thereof. Monocarboxylic acid hydrazides; isophthalic acid mono or dihydrazide, terephthalic acid mono or dihydrazide, 1,4- or 2,6-naphthalenedicarboxylic acid mono or dihydrazide, 3,3'-, 3,4'- or 4,4 ' -Diphenyldicarboxylic acid mono or dihydrazide, diphenyl ether dicarboxylic 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 dicarboxylic acid mono or dihydrazide, 4,4 ″ -terphenyl dicarboxylic acid mono or dihydrazide, 4,4 ′ ″-quarterphenyl dicarboxylic acid mono or dihydrazide, 1,2,4-benzenetricarboxylic acid Examples thereof include polycarboxylic acid hydrazides such as mono, di or trihydrazide, pyromellitic acid mono, di, tri or tetrahydrazide, 1,4,5,8-naphthoic acid mono, di, tri or tetrahydrazide.
Examples of the benzoic acid hydrazide and its functional group-substituted derivatives include, but are not limited to, for example, 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- Alkyl group, hydroxy group, acetoxy group, amino group, acetamino group, nitrile group, such as di-t-butylbenzoic acid hydrazide, Examples include derivatives in which 1 to 5 functional groups such as a carboxy group, an alkoxycarbonyl group, a carbamoyl group, an alkoxy group, a phenyl group, a benzyl group, a cumyl group, and a hydroxyphenyl group are substituted on the phenyl residue of benzoguanamine.
Examples of the α- or β-naphthoic acid hydrazide and their functional group-substituted derivatives include, but are not limited to, for example, 3-hydroxy-2-naphthoic acid hydrazide, 6-hydroxy-2-naphthoic acid hydrazide Is mentioned.

The (B) formaldehyde inhibitor was supported on a layered material or a porous material (hydrotalcite, montmorillonite, silica gel, alumina, titania, zirconia, sepiolite, smectite, palygorskite, imogolite, zeolite, activated carbon, etc.). It may be used in the form.
In addition, in conversion of the quantity (mass part) of (B) component in the manufacturing method of the polyacetal resin composition of this embodiment, the mass of these support bodies shall not be included.
Among the above-mentioned (B) formaldehyde inhibitors, aminotriazine compounds, guanamine compounds, particularly aromatic guanamine compounds; urea compounds, particularly cyclic urea compounds; carboxylic acid hydrazide compounds, especially aliphatic carboxylic acid hydrazide compounds And / or aromatic carboxylic acid hydrazide compounds are preferably used.
Among these, aliphatic carboxylic acid hydrazide compounds and aromatic carboxylic acid hydrazide compounds are particularly preferable.
Among the aliphatic carboxylic acid hydrazide compounds and aromatic carboxylic acid hydrazide compounds, dihydrazides such as adipic acid dihydrazide, sebacic acid dihydrazide, dodecadioic acid dihydrazide, isophthalic acid dihydrazide and terephthalic acid dihydrazide are effective in suppressing formaldehyde. It is preferable from the viewpoint.
In the manufacturing method of the polyacetal resin composition of this embodiment, the addition amount of (B) formaldehyde inhibitor shall be 0.01-0.5 mass part with respect to 100 mass parts of (A) polyacetal resin, Preferably it is 0.01-0.3 mass part, Preferably it is 0.02-0.2 mass part.

((C) Colorant)
Examples of the colorant (C) include organic pigments and inorganic pigments, but are not particularly limited, and only one type may be used alone or two or more types may be used in combination.
Examples of the organic pigment include, but are not limited to, for example, phthalocyanine pigments, condensed azo pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments, perylene pigments, and the like. Examples thereof include condensed polycyclic pigments.
Examples of the inorganic pigment include, but are not limited to, carbon black, metal powder, metal oxide or hydroxide, sulfide, silicate, carbonate, chromate, and the like. .
The carbon black may be any one produced by a furnace method, a channel method, or an acetylene method.
Examples of the metal oxide include, but are not limited to, metal complex oxides such as zinc white, titanium oxide, antimony white, iron black, bengara, red lead, chromium oxide, and titanium yellow. Examples include Svinel Green.
Examples of the metal hydroxide include, but are not limited to, alumina white, satin white, and yellow iron oxide.
Examples of the metal sulfide include, but are not limited to, zinc sulfide, lithopone, male yellow, silver vermilion, cadmium red, cadmium orange, cadmium yellow, antimony vermilion, barium sulfate, gypsum, lead sulfate, and the like. Can be mentioned.
Examples of the metal silicate include, but are not limited to, ultramarine blue.
Examples of the metal carbonate include, but are not limited to, barium carbonate, lime carbonate powder, lead white, and magnesium carbonate.
Examples of the metal chromate include, but are not limited to, chrome lead, zinc yellow, and barium chromate.
Examples of the metal powder include, but are not limited to, metal powder pigments such as aluminum powder, bronze powder, and copper powder.
(C) The addition amount of a coloring agent shall be 0.01-0.5 mass part with respect to 100 mass parts of (A) polyacetal resin, Preferably it is the range of 0.01-0.4 mass part. Yes, more preferably 0.01 to 0.3 parts by mass. By setting it as this range, the designability of the molded article of the polyacetal resin composition obtained by the production method of the present embodiment can be improved.

(D) Additive In the method for producing the polyacetal resin composition of the present embodiment, (D) an additive (hereinafter, may be referred to as (D) component or (D)) is used.
An additive is a binder used when an additive, a pigment, or the like is added to a resin.
(D) The additive is not limited to the following. For example, alcohols, fatty acid esters, polyalkylene glycols, esters of fatty acids and glycols, esters of glycerol, paraffinic oils that are liquid at room temperature From the viewpoint of lack of reactivity with the resin and little influence on physical properties, liquid paraffin of paraffinic oil is preferable. The addition amount of these (D) additives is in the range of 0.01 to 0.5 parts by weight, preferably 0.05 to 0.4 parts by weight, more preferably 100 parts by weight of (A) polyacetal resin. 0.05 to 0.3 parts by mass.

(Other additives)
Furthermore, the manufacturing method of the polyacetal resin composition of the present embodiment is a lubricant used in the conventional polyacetal resin composition, various inorganic fillers, and the like within a range that does not impair the object of the present invention, depending on desired characteristics. Thermoplastic resins, softeners, crystal nucleating agents, mold release agents, and the like may be added.

(Production method of polyacetal resin composition)
In the present embodiment, (A) 100 parts by mass of a polyacetal resin, (B) 0.01 to 0.5 parts by mass of a formaldehyde inhibitor, (C) 0.01 to 5 parts by mass of a colorant, and (D) A polyacetal resin composition is produced using 0.01 to 0.5 parts by mass of the additive.
In the present embodiment, the (A) polyacetal resin and the (D) additive are mixed, and the surface of the (A) is impregnated with the (D) additive;
Then, (B) adding and mixing the formaldehyde inhibitor,
Thereafter, (C) adding and mixing the colorant;
Furthermore, it is extruded and kneaded with an extruder to obtain a polyacetal resin composition.
First, the step of impregnating the component (D) on the surface of the component (A), mixing the component (B), and then mixing the component (C) is performed. As a result, an effect of reducing the amount of formaldehyde generated and reducing process variation can be obtained.
In the production process of the polyacetal resin composition of the present embodiment, mixing of (B) formaldehyde inhibitor, (C) colorant, and (D) additive can be performed using a general blender.
Moreover, in the manufacturing method of the polyacetal resin composition of this embodiment, after mixing the said component (A)-(D), it is a part among said each raw material using the melt kneader generally used. The target polyacetal resin composition can be obtained by mixing while melting. Examples of the melt kneader include a single screw extruder and a twin screw extruder. The temperature in the melt-kneading step is preferably 180 to 230 ° C., and in order to maintain the quality and working environment, the inside of the system may be replaced with an inert gas, or degassed with a single-stage or multistage vent. preferable.

[Molded body]
A molded body using the polyacetal resin composition obtained by the production method of the present embodiment can be produced by a known molding method. Although not limited to the following, for example, extrusion molding, injection molding, vacuum molding, blow molding, injection compression molding, decorative molding, gas assist injection molding, firing injection molding, low pressure molding, ultra-thin injection molding Methods such as high-speed injection molding) and in-mold composite molding (insert molding, outsert molding) can be used. In particular, from the viewpoints of quality, production stability, economy, and the like, injection molding, injection compression molding, and a molding method in which these are combined with in-mold composite molding are preferable.
Furthermore, adhesion between the polyacetal resin composition obtained by the production method of the present embodiment and various resins including rubber and / or elastomer (ultrasonic bonding, high frequency bonding, hot plate bonding, hot press molding, multilayer injection molding, multilayer coating) A molded body having two or more layers can be produced by any method such as blow molding. Thereby, excellent performance (impact resistance, slidability, chemical resistance, etc.) of various resins can be imparted, and a molded body having an appearance having excellent design properties can be obtained.

[Use]
The molded body obtained by the above production method can be used particularly for interior / exterior parts having a mechanism part and a sliding part.
For example, the molded body may be any one selected from the group consisting of OA equipment, music / video or information equipment, parts provided in communication equipment, industrial parts provided in office furniture or residential equipment, and automobile interior and exterior parts. Used as a part.

  Hereinafter, the present invention will be described with reference to specific examples and comparative examples. However, the present invention is not limited to the following examples.

The evaluation method of the resin composition manufactured by the Example and comparative example which are mentioned later is shown below.
〔Evaluation method〕
(Formaldehyde generation amount (measured by VDA275 method))
The pellets of the polyacetal resin composition obtained in the following examples and comparative examples were cooled using an injection molding machine (trade name “IS-100GN” manufactured by Toshiba Machine Co., Ltd.) at a cylinder temperature of 220 ° C., an injection time of 15 seconds, and cooling. A test piece was produced by molding for 20 seconds at a mold temperature of 77 ° C, and the amount of formaldehyde released from the test piece was determined by the following method (VDA275 method).
First, 50 mL of distilled water and a test piece (length 100 mm × width 40 mm × thickness 3 mm sheet) were placed in a 500 mL polyethylene container, sealed, and heated at 60 ° C. for 3 hours.
Thereafter, formaldehyde in distilled water was reacted with acetylacetone in the presence of ammonium ions.
About the reaction material, the absorption peak of wavelength 412nm was measured with UV spectrometer, and formaldehyde generation amount (mg / kg) was calculated | required.

It shows below about the raw material of the polyacetal resin composition used in the Example and comparative example which are mentioned later.
[Main raw materials]
((A) polyacetal resin)
(A-1)
A jacketed biaxial paddle type continuous polymerization machine that can pass a heat medium is adjusted to 80 ° C., water + formic acid = 4 ppm of trioxane at 40 mol / hr, and at the same time 1,3-dioxolane as cyclic formal 5 Each was supplied to the polymerization apparatus at a rate of 0.0 mol / hr. In addition, boron trifluoride-di-n-butyl etherate dissolved in cyclohexane as a polymerization catalyst is 5 × 10 ⁻⁵ mol with respect to 1 mol of trioxane, and methylal [( CH ₃ O) ₂ CH ₂ ] was continuously fed so as to be 2 × 10 ⁻³ mol per 1 mol of trioxane, and polymerization was performed to obtain a polymer.
The polymer discharged from the polymerization machine was put into a 1% aqueous solution of triethylamine to completely deactivate the polymerization catalyst. Thereafter, the polymer was filtered and washed to obtain a crude polyacetal resin.
Triethyl (2-hydroxyethyl) ammonium formate as a quaternary ammonium compound is added to 1 part by mass of the crude polyacetal resin after filtration and washing so as to be 20 ppm by mass in terms of the amount of nitrogen. Mixed and then dried at 120 ° C.
Next, using a side feed port and a twin screw extruder with a liquid addition line (set at a preset temperature of 200 ° C.), 100 parts by mass of the crude polyacetal resin after drying is fed from the main feed port and further melted. The crude polyacetal resin was fed with a 2% by weight triethylamine aqueous solution at a rate of 5 parts by mass to decompose unstable terminal parts.
Then, it deaerated to -0.07 MPa from the vent provided in the back | latter stage.
Furthermore, 0.3 part by mass of triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] from the side feed port provided at the rear stage of the vent, calcium stearate 0 0.05 part by mass, and further 0.025 part by mass of polyamide 66 were added, and melt kneading was performed to obtain a polyacetal resin.
From the die portion of the extruder, the polyacetal resin produced as described above was extruded as a strand, pelletized, and dried in a gear oven set at 80 ° C. for 5 hours to obtain pellets. The obtained polyacetal resin contained 4.0 mol% of comonomer (based on the oxymethylene unit), had a melt flow rate of 9.0 g / 10 min, and the formaldehyde generation amount measured by VDA275 was 15 mg / kg. It was.

(A-2)
The polymer (a-1) was filtered and washed to obtain a crude polyacetal resin, and then dried without adding a quaternary ammonium compound.
Other conditions were the same as (a-1) described above to produce a polyacetal resin.
The obtained polyacetal resin contained 4.0 mol% of comonomer (based on the oxymethylene unit), had a melt flow rate of 9.3 g / 10 min, and the formaldehyde generation amount measured by VDA275 was 30 mg / kg. It was.

(A-3)
A jacketed biaxial paddle type continuous polymerization machine that can pass a heat medium is adjusted to 80 ° C., water + formic acid = 4 ppm of trioxane at 40 mol / hr, and at the same time 1,3-dioxolane as cyclic formal 5 Each was supplied to the polymerization apparatus at a rate of 0.0 mol / hr. In addition, boron trifluoride-di-n-butyl etherate dissolved in cyclohexane as a polymerization catalyst is 5 × 10 ⁻⁵ mol with respect to 1 mol of trioxane, and methylal [( CH ₃ O) ₂ CH ₂ ] was continuously fed so as to be 2 × 10 ⁻³ mol per 1 mol of trioxane, and polymerization was performed to obtain a polymer.
The polymer discharged from the polymerization machine was put into a 1% aqueous solution of triethylamine to completely deactivate the polymerization catalyst, and then the polymer was filtered and washed to obtain a crude polyacetal resin.
Triethyl (2-hydroxyethyl) ammonium formate as a quaternary ammonium compound is added to 1 part by mass of the crude polyacetal resin after filtration and washing so as to be 20 ppm by mass in terms of the amount of nitrogen. Mixed and then dried at 120 ° C.
Next, using a side feed port and a twin screw extruder with a liquid addition line (set at a preset temperature of 200 ° C.), 100 parts by mass of the crude polyacetal resin after drying is fed from the main feed port and further melted. The crude polyacetal resin was fed with a 2% by weight triethylamine aqueous solution at a rate of 5 parts by mass to decompose unstable terminal parts.
Then, it deaerated to -0.07 MPa from the vent provided in the back | latter stage. Furthermore, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate: 0.5 parts by mass, 2-2 ′ [2′-hydroxy-3] from a side feed port provided at the rear stage of the vent ', 5'-bis] α, α-dimethylbasyl) phenyl] -2H-benzotriazole, 0.5 parts by mass of calcium stearate, and 0.025 parts by mass of polyamide 66 are added and melt-kneaded. A polyacetal resin was obtained.
From the die portion of the extruder, the polyacetal resin produced as described above was extruded as a strand, pelletized, and dried in a gear oven set at 80 ° C. for 5 hours to obtain pellets. The obtained polyacetal resin contained 4.0 mol% of comonomer (based on the oxymethylene unit), the melt flow rate was 9.5 g / 10 min, and the amount of formaldehyde generated by VDA275 was 18 mg / kg. It was.

((B) Formaldehyde inhibitor)
(B-1) Sebacic acid dihydrazide (trade name SDH, manufactured by Nippon Finechem)
(B-2) Adipic acid dihydrazide (trade name ADH, manufactured by Nippon Finechem)
(B-3) Benzoguanamine (Reagent benzoguanamine manufactured by Wako Pure Chemical Industries, Ltd.)

((C) Colorant)
(C-1) Titanium dioxide (Titanics JR-600A manufactured by Teika Co., Ltd.)
(C-2) Carbon black (trade name acetylene black manufactured by Denki Kagaku Kogyo Co., Ltd.)
(C-3) Aluminum pigment (trade name Sylvex 883-20C manufactured by Silver Line)

(D) Adjunct (d-1) Liquid paraffin (Matsumura Oil Research Co., Ltd. trade name Smoyl PS-260)

[Example 1]
(A-1) 100 parts by mass of a polyacetal resin and (d-1) 0.1 part by mass of an additive were put into a tumbler and mixed for 10 minutes.
Next, 0.05 part by mass of (b-1) formaldehyde inhibitor was added and mixed for 10 minutes.
Next, (c-1) 0.3 part by mass of a color pigment was added and further mixed for 10 minutes to obtain a mixture.
Using a vented single screw extruder with a cylinder diameter of 65 mmφ, the mixture obtained as described above was vacuum degassed under the conditions of a preset temperature of 200 ° C., a rotation speed of 100 rpm, and a discharge rate of 100 kg / hour. Time extrusion was performed and 5 kg of pellets were sampled every 30 minutes.
After the obtained pellets were dried at 80 ° C. for 3 hours, the amount of formaldehyde generated (VDA275) was measured to determine the process variation. The measurement results are shown in Table 1 below.
In addition, for the purpose of examining the analysis error of the formaldehyde generation amount (VDA275), the same operation as described above was performed in another batch, and samples from about 10 minutes to 35 minutes after the start: about 25 kg were sampled. Next, the obtained sample was uniformly blended and dried at 80 ° C. for 3 hours, and then the amount of formaldehyde generated (VDA275) was measured to determine the repetition error in the analysis.
The results are shown below.
Measured value (n = 6) 1.0, 1.0, 1.0, 1.1, 1.0, 1.0 (mg / kg)
Mean value; x = 1.02 (mg / kg), standard deviation; σn-1 = 0.04, coefficient of variation; σn-1 / x = 3.9%

[Example 2]
(A-1) 100 parts by mass of a polyacetal resin and (d-1) 0.1 part by mass of an additive were added to a tumbler and mixed for 10 minutes.
Next, 0.05 part by mass of (b-1) formaldehyde inhibitor was added and mixed for 10 minutes.
Next, (c-1) 0.3 parts by mass of a color pigment was added, and mixing was further performed for 20 minutes to obtain a mixture. The mixture obtained as described above was simply combined with a vented single cylinder having a cylinder diameter of 65 mmφ. Using a shaft extruder, extrusion was performed for about 3 hours while vacuum degassing under the conditions of a preset temperature of 200 ° C., a rotation speed of 100 rpm, and a discharge rate of 100 kg / hour, and 5 kg of pellets were sampled every 30 minutes.
After the obtained pellets were dried at 80 ° C. for 3 hours, the amount of formaldehyde generated (VDA275) was measured to determine the process variation. The measurement results are shown in Table 1 below.

Example 3
(A-1) 100 parts by mass of a polyacetal resin and (d-1) 0.1 part by mass of an additive were added to a tumbler and mixed for 10 minutes.
Next, 0.05 part by mass of (b-1) formaldehyde inhibitor was added and mixed for 20 minutes.
Next, (c-1) 0.3 part by weight of a color pigment was added, and further mixed for 20 minutes to obtain a mixture.
The mixture obtained as described above was subjected to about 6 while vacuum degassing using a vented single screw extruder having a cylinder diameter of 65 mmφ under the conditions of a set temperature of 200 ° C., a rotation speed of 100 rpm, and a discharge rate of 100 kg / hour. Time extrusion was performed and 5 kg of pellets were sampled every 30 minutes.
After the obtained pellets were dried at 80 ° C. for 3 hours, the amount of formaldehyde generated (VDA275) was measured to determine the process variation. The measurement results are shown in Table 1 below.

[Comparative Example 1]
(A-1) 100 parts by mass of a polyacetal resin and (d-1) 0.1 part by mass of an additive were added to a tumbler and mixed for 10 minutes.
Next, 0.05 part by mass of (b-1) formaldehyde inhibitor and 0.3 part by mass of (c-1) color pigment were added simultaneously and mixed for 20 minutes to obtain a mixture.
Using a vented single screw extruder with a cylinder diameter of 65 mmφ, the mixture obtained as described above was vacuum degassed under the conditions of a preset temperature of 200 ° C., a rotation speed of 100 rpm, and a discharge rate of 100 kg / hour. Time extrusion was performed and 5 kg of pellets were sampled every 30 minutes.
After the obtained pellets were dried at 80 ° C. for 3 hours, the amount of formaldehyde generated (VDA275) was measured to determine the process variation. The measurement results are shown in Table 1 below.

[Comparative Example 2]
(A-1) 100 parts by mass of a polyacetal resin and (d-1) 0.1 part by mass of an additive were added to a tumbler and mixed for 10 minutes.
Next, 0.05 part by mass of (b-1) formaldehyde inhibitor and 0.3 part by mass of (c-1) color pigment were added simultaneously and mixed for 30 minutes to obtain a mixture.
Using a vented single screw extruder with a cylinder diameter of 65 mmφ, the mixture obtained as described above was vacuum degassed under the conditions of a preset temperature of 200 ° C., a rotation speed of 100 rpm, and a discharge rate of 100 kg / hour. Time extrusion was performed and 5 kg of pellets were sampled every 30 minutes.
After the obtained pellets were dried at 80 ° C. for 3 hours, the amount of formaldehyde generated (VDA275) was measured to determine the process variation. The measurement results are shown in Table 1 below.

[Comparative Example 3]
(A-1) 100 parts by mass of a polyacetal resin and (d-1) 0.1 part by mass of an additive were added to a tumbler and mixed for 10 minutes.
Next, 0.05 part by mass of (b-1) formaldehyde inhibitor and 0.3 part by mass of (c-1) color pigment were simultaneously added and mixed for 40 minutes to obtain a mixture.
The mixture obtained as described above was subjected to about 7 while vacuum degassing using a vented single screw extruder with a cylinder diameter of 65 mmφ at a set temperature of 200 ° C., a rotation speed of 100 rpm, and a discharge rate of 100 kg / hour. Extrusion of time was performed and 10 kg of pellets were sampled every hour.
After the obtained pellets were dried at 80 ° C. for 3 hours, the amount of formaldehyde generated (VDA275) was measured to determine the process variation. The measurement results are shown in Table 1 below.

Example 4
As shown in Table 1 below, the color pigment (c-1) of [Example 1] was changed to (c-2) and the addition amount was changed. Other conditions were the same as in Example 1, and a pellet of the polyacetal resin composition was produced. The measurement results are shown in Table 1 below.

[Comparative Example 4]
As shown in Table 1 below, (c-1) the colored pigment of [Comparative Example 1] was changed to (c-2), and the addition amount was changed. Other conditions were the same as in Comparative Example 1, and pellets of the polyacetal resin composition were produced. The measurement results are shown in Table 1 below.

Example 5
The (a-1) polyacetal resin of [Example 1] described above was changed to (a-2) as shown in Table 1 below. Other conditions were the same as in Example 1, and a pellet of the polyacetal resin composition was produced. The measurement results are shown in Table 1 below.

[Comparative Example 5]
The (a-1) polyacetal resin of [Comparative Example 1] described above was changed to (a-2) as shown in Table 1 below. Other conditions were the same as in Comparative Example 1, and pellets of the polyacetal resin composition were produced. The measurement results are shown in Table 1 below.

Example 6
(A-3) 100 parts by mass of a polyacetal resin and (d-1) 0.1 part by mass of an additive were charged into a tumbler and mixed for 10 minutes.
Next, 0.05 / 0.05 part by mass of (b-1) / (b-2) formaldehyde inhibitor was added and mixed for 10 minutes.
Next, 2.0 parts by mass of (c-3) the color pigment was added, and further mixed for 10 minutes to obtain a mixture.
Using a vented single screw extruder with a cylinder diameter of 65 mmφ, the mixture obtained as described above was vacuum degassed under the conditions of a preset temperature of 200 ° C., a rotation speed of 100 rpm, and a discharge rate of 100 kg / hour. Time extrusion was performed and 5 kg of pellets were sampled every 30 minutes.
After the obtained pellets were dried at 80 ° C. for 3 hours, the amount of formaldehyde generated (VDA275) was measured to determine the process variation. The measurement results are shown in Table 1 below.

[Comparative Example 6]
(A-3) 100 parts by mass of polyacetal resin and 0.1 part by mass of (d-1) additive were added to a tumbler and mixed for 10 minutes.
Next, 0.05 / 0.05 parts by mass of (b-1) / (b-2) formaldehyde inhibitor and 2.0 parts by mass of (c-3) color pigment were added simultaneously, and for 20 minutes. Mixing was performed to obtain a mixture. Using a vented single screw extruder with a cylinder diameter of 65 mmφ, the mixture obtained as described above was vacuum degassed under the conditions of a preset temperature of 200 ° C., a rotation speed of 100 rpm, and a discharge rate of 100 kg / hour. Time extrusion was performed and 5 kg of pellets were sampled every 30 minutes.
After the obtained pellets were dried at 80 ° C. for 3 hours, the amount of formaldehyde generated (VDA275) was measured to determine the process variation. The measurement results are shown in Table 1 below.

Example 7
As shown in Table 2 below, the (b-1) formaldehyde inhibitor in [Example 1] was changed to (b-3) and the addition amount was changed. Other conditions were the same as in Example 1, and a pellet of the polyacetal resin composition was produced. The measurement results are shown in Table 2 below.

[Comparative Example 7]
The (b-1) formaldehyde inhibitor of [Comparative Example 1] described above was changed to (b-3) as shown in Table 2 below, and the addition amount was changed. Other conditions were the same as in Comparative Example 1, and pellets of the polyacetal resin composition were produced. The measurement results are shown in Table 2 below.

[Comparative Example 8]
As shown in Table 2 below, the (b-1) formaldehyde inhibitor in [Example 1] was changed to (b-3) and the addition amount was changed. Other conditions were the same as in Example 1, and a pellet of the polyacetal resin composition was produced. The measurement results are shown in Table 2 below.

[Comparative Example 9]
The (b-1) formaldehyde inhibitor of [Comparative Example 1] described above was changed to (b-3) as shown in Table 2 below, and the addition amount was changed. Other conditions were the same as in Comparative Example 1, and pellets of the polyacetal resin composition were produced. The measurement results are shown in Table 2 below.

Example 8
In the above-mentioned (b-1) formaldehyde inhibitor of [Example 1], the addition amount was changed as shown in Table 2 below. Other conditions were the same as in Example 1, and a pellet of the polyacetal resin composition was produced. The measurement results are shown in Table 2 below.

[Comparative Example 10]
In the above-mentioned (b-1) formaldehyde inhibitor of [Comparative Example 1], the addition amount was changed as shown in Table 2 below. Other conditions were the same as in Comparative Example 1, and pellets of the polyacetal resin composition were produced. The measurement results are shown in Table 2 below.

Example 9
In the above-mentioned (b-1) formaldehyde inhibitor of [Example 1], the addition amount was changed as shown in Table 2 below. Other conditions were the same as in Example 1, and a pellet of the polyacetal resin composition was produced. The measurement results are shown in Table 2 below.

[Comparative Example 11]
In the above-mentioned (b-1) formaldehyde inhibitor of [Comparative Example 1], the addition amount was changed as shown in Table 2 below. Other conditions were the same as in Comparative Example 1, and pellets of the polyacetal resin composition were produced. The measurement results are shown in Table 2 below.

[Comparative Example 12]
In the above-mentioned (b-1) formaldehyde inhibitor of [Example 1], the addition amount was changed as shown in Table 2 below. Other conditions were the same as in Example 1, and a pellet of the polyacetal resin composition was produced. The measurement results are shown in Table 2 below.

[Comparative Example 13]
In the above-mentioned (b-1) formaldehyde inhibitor of [Comparative Example 1], the addition amount was changed as shown in Table 2 below. Other conditions were the same as in Comparative Example 1, and pellets of the polyacetal resin composition were produced. The measurement results are shown in Table 2 below.

  As shown in Tables 1 and 2, it was found that all the polyacetal resin compositions produced by the production methods of Examples 1 to 9 were remarkably suppressed in process variations in the amount of formaldehyde generated.

  The method for producing a polyacetal resin composition of the present invention makes it possible to produce a polyacetal resin composition in which process fluctuations in the amount of formaldehyde generated are suppressed, and simplification of analysis and evaluation in a later process is possible. There is an industrial applicability as a method for producing a polyacetal resin composition that eliminates the need for mixing a compound having formaldehyde scavenging performance and can save labor significantly.

Claims (4)

(A) polyacetal resin: 100 parts by mass;
(B) Formaldehyde inhibitor: 0.01 to 0.5 parts by mass;
(C) Colorant: 0.01 to 5 parts by mass;
(D) Additive: 0.01 to 0.5 parts by mass;
A process for producing a polyacetal resin composition comprising:
Mixing the (A) polyacetal resin and the (D) additive, and impregnating the (D) additive on the surface of the (A);
Then, (B) adding and mixing the formaldehyde inhibitor,
Thereafter, the step of adding and mixing the colorant (C), the step of extrusion kneading with an extruder,
The manufacturing method of the polyacetal resin composition which has these. The (B) formaldehyde inhibitor is an aliphatic carboxylic acid hydrazide compound and / or an aromatic carboxylic acid hydrazide compound,
The manufacturing method of the polyacetal resin composition of Claim 1 which makes content of the said (B) formaldehyde inhibitor 0.01-0.3 mass part. The (B) formaldehyde inhibitor is at least one selected from the group consisting of adipic acid dihydrazide, sebacic acid dihydrazide, dodecadioic acid dihydrazide, isophthalic acid dihydrazide and terephthalic acid dihydrazide,
The manufacturing method of the polyacetal resin composition of Claim 1 or 2 which makes content of the said (B) formaldehyde inhibitor 0.02-0.3 mass part.   The manufacturing method of the polyacetal resin composition as described in any one of Claims 1 thru | or 3 whose said (A) polyacetal resin is 20 mg / kg or less in the amount of formaldehyde measured by VDA275.