阅读说明：本技术 树脂组合物 (Resin composition ) 是由 歌岛贤治 近藤知宏 于 2019-06-27 设计创作，主要内容包括：本发明的目的在于提供一种树脂组合物,其可以制造甲醛的产生少、同时具有优良的金属色调外观的成型品。本发明的树脂组合物的特征在于,其含有：(A)聚缩醛树脂100质量份；(B)体积平均粒径为3μm～40μm且平均粒子厚度为0.03μm～0.4μm的金属粒子0.1质量份～10质量份；和(C)氧原子的质量比例为1％～36％的聚亚烷基二醇化合物0.01质量份～5质量份。另外,本发明的树脂组合物的特征在于,其含有：(A)聚缩醛树脂100质量份；和(D)金属颜料0.1质量份～15质量份,所述(D)金属颜料含有(B)体积平均粒径为3μm～40μm且平均粒子厚度为0.03μm～0.4μm的金属粒子和(C)氧原子的质量比例为1％～36％的聚亚烷基二醇化合物。(The purpose of the present invention is to provide a resin composition which can produce a molded article that generates little formaldehyde and has an excellent metallic appearance. The resin composition of the present invention is characterized by containing: (A) 100 parts by mass of a polyacetal resin; (B) 0.1 to 10 parts by mass of metal particles having a volume average particle diameter of 3 to 40 μm and an average particle thickness of 0.03 to 0.4 μm; and (C) 0.01 to 5 parts by mass of a polyalkylene glycol compound having an oxygen atom content of 1 to 36% by mass. The resin composition of the present invention is characterized by containing: (A) 100 parts by mass of a polyacetal resin; and (D) 0.1 to 15 parts by mass of a metallic pigment comprising (B) metal particles having a volume average particle diameter of 3 to 40 [ mu ] m and an average particle thickness of 0.03 to 0.4 [ mu ] m and (C) a polyalkylene glycol compound having an oxygen atom content of 1 to 36% by mass.)

1. A resin composition, characterized in that the resin composition contains:

(A) 100 parts by mass of a polyacetal resin;

(B) 0.1 to 10 parts by mass of metal particles having a volume average particle diameter of 3 to 40 μm and an average particle thickness of 0.03 to 0.4 μm; and

(C) 0.01 to 5 parts by mass of a polyalkylene glycol compound having an oxygen atom mass ratio of 1 to 36% based on the mass of the whole compound.

2. A resin composition, characterized in that the resin composition contains:

(A) 100 parts by mass of a polyacetal resin; and

(D) 0.1 to 15 parts by mass of a metallic pigment (D) containing

(B) Metal particles having a volume average particle diameter of 3 to 40 μm and an average particle thickness of 0.03 to 0.4 μm, and

(C) a polyalkylene glycol compound in which the proportion of the mass of oxygen atoms in the mass of the whole compound is 1 to 36%.

3. The resin composition according to claim 2, wherein the metal particles (B) are contained in the metal pigment (D) in an amount of 70 to 95% by mass.

4. The resin composition according to any one of claims 1 to 3, wherein the polyalkylene glycol compound (C) has a number average molecular weight of 500 to 10000.

5. The resin composition according to any one of claims 1 to 4, wherein the polyalkylene glycol compound (C) has a repeating unit derived from an oxyalkylene group having 4 or more carbon atoms.

6. The resin composition according to any one of claims 1 to 5, wherein the metal particles (B) contain aluminum.

7. The resin composition according to any one of claims 1 to 6, further comprising (E) a lubricant.

Technical Field

The present invention relates to a resin composition.

Background

Crystalline resins have a plurality of useful characteristics such as high mechanical strength and rigidity, and excellent chemical resistance. Since this crystalline resin is easy to process, it has been used in a wide range including mechanical parts and sliding parts in precision instruments, home appliances, office automation equipment, automobiles, industrial materials, daily necessities, and the like.

In addition, in order to impart a characteristic metallic luster called metallic tone (メ タ リ ッ ク) to various resins, metallic color pigments including metallic particles typified by aluminum flakes (hereinafter also referred to as "aluminum flakes") are blended. Resin compositions containing the metallic coloring pigments are used for interior and exterior parts of automobiles, computer housings, and the like.

As such a resin composition, for example, a resin composition described in the following patent documents is known, and for example, an attempt is made to impart design properties by molding a resin containing a bright pigment to express metallic gloss. Specifically, patent documents 1 and 2 disclose molded articles comprising a synthetic resin composition containing a specific metal pigment. Further, patent document 3 proposes a polyacetal resin composition containing a weather-resistant agent, aluminum particles having a specific particle diameter, particle size distribution and particle thickness, and a specific fatty acid, and discloses that the composition is excellent in production stability, mechanical properties, molding appearance, welding performance and lightness. Further, patent document 4 proposes a polyacetal resin composition containing a polyacetal resin, a metallic coloring pigment and a specific liquid additive, and discloses that the composition is excellent in extrusion characteristics, retention stability at the time of molding and appearance characteristics, has a reduced content of an organic solvent, and gives a metallic tone appearance. Further, patent document 5 discloses a polymer composition comprising a polyacetal resin, a metallic pigment and an ultraviolet stabilizer, and the metallic pigment and the ultraviolet stabilizer are dispersed in amounts sufficient to make the glossiness of the outer surface of the obtained molded article to be a certain level or more.

Disclosure of Invention

Problems to be solved by the invention

However, when the methods described in patent documents 1 and 2 are applied to a polyacetal resin, sufficient effects cannot be obtained with respect to suppression of the amount of formaldehyde generated and improvement of the appearance such as the gloss of a product due to heat generation during melt mixing and the influence of active sites on the metal surface.

In addition, with respect to the technique disclosed in patent document 3, no study has been made on the influence on the amount of formaldehyde generated, the influence on the appearance such as the glossiness of the product, and the like.

Patent document 4 proposes a technique for the purpose of suppressing the generation of formaldehyde and the thermal stability of the molded article, but discloses only a pigment obtained by dispersing aluminum powder in polyethylene as a metallic pigment, and does not study the influence on the appearance such as the gloss and brightness of the molded article obtained.

Further, patent document 5 is completely silent on the influence of other additives on glossiness and the like.

Accordingly, an object of the present invention is to provide a resin composition which can produce a molded article having excellent metallic appearance with less formaldehyde generation.

Means for solving the problems

The inventors of the present invention conducted extensive studies and found that: the present inventors have found that a resin composition which is reduced in formaldehyde emission and has an excellent metallic tone appearance can be obtained by adding a polyalkylene glycol compound to a polyacetal resin at a specific mass ratio, the polyalkylene glycol compound having a specific mass ratio of metal particles having a specific shape to oxygen atoms in a specific range based on the mass of the entire compound, and have completed the present invention.

[1]

A resin composition, characterized in that the resin composition contains:

(A) 100 parts by mass of a polyacetal resin;

(B) 0.1 to 10 parts by mass of metal particles having a volume average particle diameter of 3 to 40 μm and an average particle thickness of 0.03 to 0.4 μm; and

(C) 0.01 to 5 parts by mass of a polyalkylene glycol compound having an oxygen atom mass ratio of 1 to 36% based on the mass of the whole compound.

[2]

A resin composition, characterized in that the resin composition contains:

(A) 100 parts by mass of a polyacetal resin; and

(D) 0.1 to 15 parts by mass of a metallic pigment (D) containing

(B) Metal particles having a volume average particle diameter of 3 to 40 μm and an average particle thickness of 0.03 to 0.4 μm, and

(C) a polyalkylene glycol compound in which the proportion of the mass of oxygen atoms in the mass of the whole compound is 1 to 36%.

[3]

The resin composition according to [2], wherein the metal particles (B) are contained in the metal pigment (D) in a proportion of 70 to 95% by mass.

[4]

The resin composition according to any one of [1] to [3], wherein the polyalkylene glycol compound (C) has a number average molecular weight of 500 to 10000.

[5]

The resin composition according to any one of [1] to [4], wherein the polyalkylene glycol compound (C) has a repeating unit derived from an oxyalkylene group having 4 or more carbon atoms.

[6]

The resin composition according to any one of [1] to [5], wherein the metal particles (B) contain aluminum.

[7]

The resin composition according to any one of [1] to [6], further comprising (E) a lubricant.

Effects of the invention

According to the present invention, there can be provided a resin composition which can produce a molded article having excellent metallic appearance with little formaldehyde emission.

Drawings

Fig. 1 is a schematic diagram illustrating an FI value evaluation method in the example.

Detailed Description

Hereinafter, a mode for carrying out the present invention (hereinafter, may be referred to as "the present embodiment") will be described in detail. The present invention is not limited to the following description, and various modifications can be made within the scope of the present invention.

[ resin composition ]

The resin composition of the first embodiment of the present invention contains: (A) 100 parts by mass of a polyacetal resin; (B) 0.1 to 10 parts by mass of metal particles having a volume average particle diameter of 3 to 40 μm and an average particle thickness of 0.03 to 0.4 μm; and (C) 0.01 to 5 parts by mass of a polyalkylene glycol compound having an oxygen atom content of 1 to 36% by mass of the entire compound.

The resin composition of the second embodiment of the present invention contains: (A) 100 parts by mass of a polyacetal resin; and (D) 0.1 to 15 parts by mass of a metallic pigment containing (B) metal particles having a volume average particle diameter of 3 to 40 [ mu ] m and an average particle thickness of 0.03 to 0.4 [ mu ] m and (C) a polyalkylene glycol compound in which the proportion of the mass of oxygen atoms in the mass of the entire compound is 1 to 36%.

Hereinafter, "(B) metal particles having a volume average particle diameter of 3 to 40 μm and an average particle thickness of 0.03 to 0.4 μm" will be referred to as "(B) metal particles", "polyalkylene glycol compound having a proportion of the mass of the (C) oxygen atom of 1 to 36% in the mass of the entire compound" will be referred to as "(C) polyalkylene glycol compound", and "metal pigment (D) containing (B) metal particles having a volume average particle diameter of 3 to 40 μm and an average particle thickness of 0.03 to 0.4 μm and a proportion of the mass of the (C) oxygen atom of 1 to 36% in the mass of the entire compound" will be referred to as "(D) metal pigment".

((A) polyacetal resin)

The polyacetal resin (a) in the present embodiment is not particularly limited, and conventionally known polyacetals can be used. (A) The polyacetal resins may be used singly or in combination of two or more.

Examples of the polyacetal resin (A) include: substantially consisting of oxymethylene units- (CH) obtained by homopolymerization of a cyclic oligomer such as formaldehyde, trioxymethylene or tetraformaldehyde₂O) -a polyoxymethylene homopolymer; or a copolymer obtained by copolymerizing formaldehyde and/or trioxymethylene with a cyclic ether and/or a cyclic formal to which a hindered phenol antioxidant is added in an amount of 1 to 500 ppm by mass, and having an oxymethylene unit- (CH)₂A polyoxymethylene copolymer having a structure in which oxyalkylene units represented by the following general formula (1) are randomly inserted into a chain of O) -.

(R in the formula₁And R₂Each being a hydrogen atom, an alkyl group or an aryl groupAnd n is an integer of 2 to 6

The polyoxymethylene copolymer used in the present embodiment also includes a branched polyoxymethylene copolymer having a branched molecular chain and a polyoxymethylene block copolymer containing at least 50 mass% of oxymethylene repeating units and having a block with a different component.

The insertion rate of the oxyalkylene unit in the polyoxymethylene copolymer is preferably 0.01 mol or more and 50 mol or less, and more preferably 0.03 mol or more and 20 mol or less, based on 100 mol of the oxymethylene unit. Examples of the oxyalkylene unit include: oxyethylene units, oxypropylene units, oxytetramethylene units, oxybutylene units, oxyphenylethylene units, and the like. Among these oxyalkylene units, oxypropylene units- [ (CH) are preferred from the viewpoint of improving the physical properties of the resin composition₂)₃O]And the oxytetramethylene unit- [ (CH)₂)₄O]-。

The polyacetal resin obtained by the above homopolymerization or copolymerization is desirably subjected to a terminal stabilization treatment. Examples of the method of stabilizing the terminal include: methods of esterifying, etherifying, carbamating the terminal hydroxyl group; or a method of stabilizing an unstable portion at the end by hydrolysis.

The polyacetal resin having been subjected to the terminal stabilization treatment is obtained, for example, by: the polyoxymethylene copolymer obtained by copolymerization of formaldehyde and/or trioxymethylene and cyclic ether and/or cyclic formal is continuously fed to a counter-rotating non-intermeshing twin screw extruder capable of performing a step of stabilizing molecular terminals immediately after polymerization, a step of kneading by injecting water, alcohol or a mixture thereof in a molten state, and a devolatilization step of releasing steam of the hydroxyl group-containing compound such as water and free formaldehyde injected, and the like. In addition, when water, alcohol or a mixture thereof is injected and kneaded as described above, it is preferable to add a basic substance such as triethylamine as a pH adjuster.

The MFR (melt flow rate; temperature condition: 190 ℃ C. according to ASTM D57E) of the polyacetal resin is preferably 2.5g/10 min to 40g/10 min, more preferably 3g/10 min to 30g/10 min. By adjusting the MFR of the polyacetal resin within the above range, the balance between the mechanical physical properties of the resin composition, the thermal stability during residence molding, and the amount of formaldehyde generated becomes good.

The content of the polyacetal resin (a) is preferably 75 to 99% by mass, more preferably 85 to 98% by mass, based on 100% by mass of the resin composition.

((B) Metal particle)

(B) The metal particles preferably have a flat shape such as coin shape or flake shape, and a volume average particle diameter (D)₅₀) 3 to 40 μm and an average particle thickness of 0.03 to 0.4 μm.

(B) The metal particles may be used singly or in combination.

As the material constituting the metal particles (B), known and conventional metal particles can be used, and among them, the metal particles (B) preferably contain aluminum, more preferably contain only aluminum, from the viewpoint of high reflectance, easy availability, and high degree of freedom in processing.

When aluminum particles are used as the (B) metal particles, it is preferable that the surface of the aluminum particles have an appropriate oxide film. By having an appropriate oxide film, high reflectance peculiar to aluminum can be maintained, and corrosion resistance and stability with time of the metal particles can be maintained.

In the case of using aluminum particles as the (B) metal particles, the purity is not particularly limited, and other metals may be contained as impurities or alloy components as long as the effects of the present invention are not hindered. Examples of the impurities or alloy components include: si, Fe, Cu, Mn, Mg, Zn, etc.

(B) The metal particles can be produced by a known method. For example, it is obtained by: the atomized powder, the cutting powder, the foil powder, the vapor deposition powder, and the metal powder obtained by another method are sorted in advance by primary classification or the like, wet-grinding treatment is performed by a ball mill, an attritor (ア ト ラ イ タ ー), a planetary mill, a vibration mill or the like in the coexistence of a grinding medium containing a grinding aid, a solvent or the like, screening classification is performed in a wet state, and then solid-liquid separation is performed by a filter press or the like. Thus, the metal particles (B) having less uneven fracture surfaces at the sheet ends can be produced.

The pulverization medium used herein is preferably as small as possible because when it is excessively added, the amount of oxygen contained in the particles becomes large.

(B) The shape of the metal particles is preferably a flat shape such as a coin shape or a sheet shape. The flat shape as used herein means the average shape ratio [ average particle thickness (t)/volume average particle diameter (D) ]₅₀)]The value of (b) is 0.2 or less, preferably 0.1 or less, and more preferably 0.05 or less. By adjusting the average shape ratio within this range, the surface area of the portion having a high reflectance peculiar to a metal can be increased by adding a small amount of (B) metal particles, and therefore, the luminance of the molded body can be effectively improved by adding a small amount of (B) metal particles.

In the first embodiment of the present invention, the content of the (B) metal particles is 0.1 to 10 parts by mass, preferably 1 to 8 parts by mass, more preferably 1.5 to 7 parts by mass, and particularly preferably 2 to 6 parts by mass, relative to 100 parts by mass of the polyacetal resin.

By adjusting the content of the metal particles within the above range, the molded article of the resin composition of the present embodiment can maintain rigidity and impact resistance inherent in polyacetal resin more favorably, suppress the generation of formaldehyde, and exhibit favorable metallic luster.

As described above, (B) the volume average particle diameter (D) of the metal particles₅₀) It is required to be 3 μm to 40 μm, preferably 4 μm or more, more preferably 5 μm or more, and preferably 35 μm or less, more preferably 30 μm or less. The volume average particle diameter (D) of the metal particles (B) is particularly preferable from the viewpoint of particularly enhancing the effect of suppressing formaldehyde emission₅₀) In the range of 5 μm to 15 μm, the volume of the metal particles (B) is particularly preferable from the viewpoint of particularly enhancing the effect of improving the glossinessAverage particle diameter (D)₅₀) In the range of 15 to 30 μm.

The volume average particle diameter (D)₅₀) The measurement can be carried out by the method described in the examples described later.

As described above, the average particle thickness (t) of the (B) metal particles needs to be 0.03 to 0.4 μm, preferably 0.08 μm or more, more preferably 0.10 μm or more, further preferably 0.12 μm or more, and further preferably 0.39 μm or less, more preferably 0.38 μm or less, further preferably 0.36 μm or less.

The average particle thickness (t) of the metal particles (B) can be calculated by the following method.

1) Method for calculating average particle thickness from water surface diffusion area (WCA)

First, the constituent component (e.g., aluminum) of the (B) metal particles is pretreated with a mineral spirit solution of 5% stearic acid, and then the water surface diffusion area (WCA) of the constituent component of the (B) metal particles is measured in accordance with JIS K5906-. Next, the water surface spread area (WCA) (m) per 1g of the constituent component obtained by the measurement can be used²The average particle thickness was calculated by the following formula.

t is 0.4/WCA (in the case where the constituent of the (B) metal particles is aluminum)

The method for calculating the average particle thickness is described in, for example, aluminum Paint and Powder, j.d. edwards&The 16 th to 22 nd pages of R.I.Wray, 3 rd edition, Reinhold Publishing Corp.New York (1955). In addition, "0.4" in the above formula is a density of aluminum of 2.7g/cm³The reciprocal of (1/2.7 ═ about 0.4).

The method for measuring the water surface diffusion area described in JIS is a method for measuring the water surface diffusion area in a suspension type, whereas aluminum (aluminum pigment) is a non-suspension type. However, the method for measuring the water surface diffusion area (WCA) of aluminum can be carried out in the same manner as the suspension type described in JIS K5906-. Pretreatment of samples is described in "paint raw materials" , 156 th, and 2 nd to 16 th pages (1980.9.1, published by Kasei corporation).

2) Method for calculating average particle thickness from Scanning Electron Microscope (SEM) observation results

In the case where the average particle thickness cannot be calculated by the method of 1) (for example, in the case where WCA measurement cannot be performed), the average particle thickness can be obtained by a method such as calculating an average value from a plurality of results obtained by observing (B) the metal particles with a Scanning Electron Microscope (SEM), for example, the thicknesses of (B) the metal particles observed at 100 positions.

By using a catalyst having a volume average particle diameter (D) within the above range₅₀) And the (B) metal particles having the average particle thickness (t), can suppress the metal particles from being broken at the time of extrusion processing or the like, and can exhibit excellent appearance characteristics and good metallic luster for a molded article produced from the resin composition of the present embodiment.

((C) polyalkylene glycol Compound)

The ratio of the mass of oxygen atoms in the polyalkylene glycol compound (C) to the mass of the whole compound is in the range of 1 to 36%.

In the first embodiment of the present invention, the content of the polyalkylene glycol compound (C) is 0.01 to 5 parts by mass, preferably 0.05 to 4 parts by mass, more preferably 0.1 to 2 parts by mass, and particularly preferably 0.2 to 1 part by mass, relative to 100 parts by mass of the polyacetal resin.

In the first embodiment of the present invention, the mass ratio of the polyalkylene glycol compound (C) to 100 parts by mass of the metal particles (B) is preferably 1 to 50 parts by mass, more preferably 2 to 40 parts by mass, still more preferably 3 to 30 parts by mass, and particularly preferably 5 to 15 parts by mass.

By adjusting the content of the polyalkylene glycol compound within the above range, the effect of improving the glossiness can be sufficiently exhibited and the generation of formaldehyde can be suppressed in the molded article of the resin composition of the present embodiment.

In the present embodiment, (C) the polyalkylene glycol compound may be used singly or in combination of two or more.

In the present embodiment, examples of the polyalkylene glycol compound (C) include: alkylene glycol (e.g. C)_3-6Alkylene glycol), esterified derivatives of polyalkylene glycols, other modified polyalkylene glycols, and the like. Specific examples thereof include: examples of the homopolymer include polypropylene glycol, polytetramethylene ether glycol, polypentamethylene ether glycol, and polyneopentylene ether glycol; examples of the copolymer include polyethylene glycol-polytetramethylene ether glycol copolymers, polypropylene glycol-polytetramethylene ether glycol copolymers, polyethylene glycol-polypentamethylene ether glycol copolymers, polypropylene glycol-polypentamethylene ether glycol copolymers, polyethylene glycol-polypivalenemethylene ether glycol copolymers, polypropylene glycol-polypivalenemethylene ether glycol copolymers, tetrahydrofuran-neopentyl glycol copolymers, and the like; examples of the esterified derivative of the polyalkylene glycol include polypropylene glycol monostearate, polypropylene glycol distearate, polytetramethylene ether glycol monostearate, polytetramethylene ether glycol distearate, polypentamethylene ether glycol monostearate, polypentamethylene ether glycol distearate, polyneopentylene ether glycol monostearate, and polyneopentylene ether glycol distearate. Among them, polypropylene glycol, polytetramethylene ether glycol, and tetrahydrofuran-neopentyl glycol copolymer are preferable, and polytetramethylene ether glycol and tetrahydrofuran-neopentyl glycol copolymer are particularly preferable.

The polyalkylene glycol compound (C) of the present embodiment is required to have a proportion of oxygen atoms by mass of 1% to 36%, preferably 15% or more, and preferably 31% or less, based on the mass of the entire compound. When the ratio of the mass of oxygen atoms to the total mass of the polyalkylene glycol compound is within the above range, the gloss of a molded article produced from the resin composition tends to be further improved. From the same viewpoint, the proportion of the mass of oxygen atoms in the polyalkylene glycol compound (C) to the mass of the whole compound is more preferably 18% or more, still more preferably 20% or more, yet more preferably 30% or less, still more preferably 24% or less.

The ratio of the mass of oxygen atoms to the mass of the entire compound can be measured by the following method.

The resin composition is pulverized, extracted in a solvent (different depending on the kind of polyalkylene glycol compound) capable of dissolving the polyalkylene glycol compound (C), the extract liquid is concentrated, the solvent is removed to obtain a sample, the structure of polyalkylene glycol is identified by NMR, the molecular weight is identified by GPC, and the mass ratio of oxygen atoms is calculated.

The polyalkylene glycol compound (C) having the ratio of the mass of oxygen atoms to the mass of the entire compound within the above range can provide a resin composition and a molded article having high gloss and excellent metallic tone appearance, and can improve the running stability during molding and extrusion. Further, the effect of suppressing the generation of formaldehyde from the resin composition and the molded article can be improved.

(C) The number average molecular weight of the polyalkylene glycol compound is preferably 500 to 10000, more preferably 1000 to 7500, further preferably 1400 to 5000, and particularly preferably 2000 to 4000. When the number average molecular weight satisfies the above range, the tendency to improve the gloss of the molded article becomes remarkable, and the generation of formaldehyde can be further suppressed.

The number average molecular weight can be measured by GPC (gel permeation chromatography) or the like.

The polyalkylene glycol compound (C) preferably has a repeating structural unit derived from an oxyalkylene group having 4 or more carbon atoms in its molecular structure. In the case where the repeating structural unit of the oxyalkylene group is an oxyalkylene group having 4 or more carbon atoms, elution of the polyalkylene glycol compound (C) can be suppressed and the tendency of lowering the surface gloss can be reduced in the case of direct exposure to water or exposure to a high humidity environment.

((D) Metal pigment)

(D) The metallic pigment contains the above-mentioned (B) metallic particles and (C) a polyalkylene glycol compound.

In the second embodiment of the present embodiment, the proportion of the metal particles (B) contained in the metal pigment (D) is preferably 75 to 95% by mass. When the above proportion is 70% by mass or more, the amount of the metallic pigment can be suppressed and the running stability at the time of extrusion and injection molding can be further improved, and when the above proportion is 95% by mass or less, the dispersibility of the metallic pigment can be improved and the scattering of the metallic powder can be suppressed at the time of blending the raw materials. From the same viewpoint, the above ratio is more preferably 80% by mass or more, and further more preferably 92% by mass or less.

(D) The proportion of the polyalkylene glycol compound (C) contained in the metallic pigment is preferably 5 to 30% by mass. When the above ratio is 5% by mass or more, the dispersibility of the metallic pigment can be improved and the scattering of the metallic powder can be suppressed at the time of blending the raw materials, and when the above ratio is 30% by mass or less, the amount of the metallic pigment can be suppressed and the running stability at the time of extrusion and injection molding can be further improved. From the same viewpoint, the above ratio is more preferably 8% by mass or more, and further more preferably 20% by mass or less.

In the second embodiment of the present embodiment, (C) the polyalkylene glycol compound is used as a pigment binder in (D) the metal pigment.

In the present embodiment, the content of the metal pigment (D) in the resin composition of the second embodiment is 0.1 to 15 parts by mass with respect to 100 parts by mass of the polyacetal resin. By adjusting the content of the (D) metallic pigment to the above range, the molded article of the resin composition of the present embodiment can more favorably maintain the rigidity and impact resistance which are the mechanical properties inherent in the polyacetal resin, and can exhibit favorable metallic luster while suppressing the generation of formaldehyde. In addition, the extruder during extrusion processing and the molding machine during injection molding can be stably operated. From the same viewpoint, the content of the metal pigment (D) in the resin composition of the present embodiment is preferably 1.0 part by mass or more, more preferably 1.5 parts by mass or more, further preferably 2.0 parts by mass or more, and further preferably 12 parts by mass or less, more preferably 10 parts by mass or less, further preferably 9.0 parts by mass or less, and particularly preferably 8.0 parts by mass or less, relative to 100 parts by mass of the polyacetal resin.

By using the metal pigment containing the polyalkylene glycol compound (C) as the metal pigment (D), stable operation of an extruder at the time of extrusion processing and a molding machine at the time of injection molding can be achieved, and also formaldehyde generation can be suppressed and the surface gloss can be greatly improved in the molded article of the resin composition of the present embodiment.

(D) The metallic pigment can be prepared, for example, by: the (B) metal particles and (C) polyalkylene glycol compound processed and shaped in a specific solvent (e.g., mineral spirits or the like) are optionally heated while being stirred and mixed, and then the solvent is evaporated by reducing the pressure.

Therefore, (D) the metal pigment may contain other components than (B) the metal particles and (C) the polyalkylene glycol compound, such as a solvent used in the preparation. However, the proportion of the other component contained in the (D) metallic pigment is preferably 5% by mass or less, more preferably 1% by mass or less, from the viewpoint of more reliably obtaining the desired effect.

In the present embodiment, the metal pigment (D) may be contained as the metal particles (B) and the polyalkylene glycol compound (C) in the resin composition of the first embodiment.

((E) Lubricant)

The resin composition of the present embodiment may further contain one or more (E) lubricants. The lubricant generally means a substance that lowers the viscosity of the resin melt and contributes to improvement of releasability from the metal surface at the time of molding, and in the present embodiment, by adding (E) the lubricant, higher glossiness and FI value are obtained in addition thereto.

(E) The lubricant may be used singly or in combination of two or more.

The lubricant (E) is not limited to the following, and examples thereof include: among them, liquid paraffin is preferred as the hydrocarbon lubricant from the viewpoint of low reactivity with the polyacetal resin (a) and small influence on physical properties.

(E) The amount of the lubricant to be added is not particularly limited as long as it does not interfere with extrusion and injection molding, and is preferably 0.01 to 0.5 parts by mass, more preferably 0.05 to 0.45 parts by mass, and particularly preferably 0.1 to 0.4 parts by mass, based on 100 parts by mass of the polyacetal resin (a). When the amount of addition is within the above range, a molded article having high gloss is obtained, and the running state of an extruder at the time of extrusion, the amount of resin metered at the time of injection molding, and the like become stable, which is preferable.

((F) Formaldehyde inhibitor)

The resin composition of the present embodiment preferably contains the following formaldehyde inhibitor as necessary within a range not to impair the object of the present invention. Examples of the formaldehyde inhibitor (F) include: aminotriazine compounds, guanamine compounds, urea compounds, carboxylic acid hydrazide compounds, and the like. These formaldehyde inhibitors may be used singly or in combination of two or more.

Examples of the aminotriazine compound include: melamine; melamine condensates such as melam, melem, and tricyano melamine (メ ロ ン); melamine resins such as melamine-formaldehyde resins; n-hydroxyarylalkylmelamine compounds such as N, N' -mono-, di-, tri-, tetra-, penta-, or hexa- (o-, m-, or p-hydroxyphenylmethyl) melamine; and the like.

Examples of the guanamine compound include: aliphatic guanamine compounds such as pentylguanamine, hexylguanamine, heptylguanamine, octylguanamine, and stearylguanamine; alkylene biguanides such as ethylene biguanide, propylene biguanide, butylene biguanide, pentylene biguanide, hexylene biguanide, heptylene biguanide, and octylene biguanide; alicyclic guanamine compounds such as cyclohexyl guanamine, norbornenyl guanamine, cyclohexenyl guanamine, norbornanyl guanamine, and functional group-substituted derivatives thereof; aromatic guanamine compounds such as phenylguanamine, α -or β -naphthylguanamine, and functional group-substituted derivatives thereof; polyguanamines such as o-phenylendiguanamine, m-phenylendiguanamine, p-phenylendiguanamine, naphthalenediguanamine, and biphenylbiguanideamine; aralkyl or aralkylene guanamines such as phenethylguanamine, β -phenylpropylguanamine, and o-, m-or p-xylylene biguanideamine; heteroatom-containing guanamine compounds such as acetal group-containing guanamines, dioxane ring-containing guanamines, tetraoxaspiro ring-containing guanamines, isocyanurate ring-containing guanamines, and the like; and the like.

Examples of the functional group-substituted derivative in the alicyclic guanamine compound include: a derivative in which a cycloalkane residue is substituted with 1 to 3 functional groups such as an alkyl group, a hydroxyl group, an amino group, an acetylamino group, a nitrile group, a carboxyl group, an alkoxycarbonyl group, a carbamoyl group, an alkoxy group, a phenyl group, a cumyl group, and a hydroxyphenyl group.

Further, examples of the functional group-substituted derivative in the aromatic guanamine compound include: the aromatic guanamine compound may be a derivative obtained by substituting 1 to 5 functional groups such as an alkyl group, a hydroxyl group, an amino group, an acetamido group, a nitrile group, a carboxyl group, an alkoxycarbonyl group, a carbamoyl group, an alkoxy group, a phenyl group, a cumyl group, and a hydroxyphenyl group with a phenyl residue of a phenylguanamine or a naphthyl residue of a naphthylguanamine, and examples of the aromatic guanamine compound include: o-, m-or p-tolylguanamine, o-, m-or p-xylyleneguanamine, o-, m-or p-phenylphenylguanamine, o-, m-or p-hydroxyphenylguanamine, 4- (4' -hydroxyphenyl) phenylguanamine, o-, m-or p-cyanophenylguanamine, 3, 5-dimethyl-4-hydroxyphenylguanamine, 3, 5-di-t-butyl-4-hydroxyphenylguanamine, and the like.

Examples of the guanamines containing an acetal group include: 2, 4-diamino-6- (3, 3-dimethoxypropyl) s-triazine, and the like.

Examples of the guanamine containing a dioxane ring include: [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, and the like.

Examples of the above-mentioned guanamines containing a tetraoxaspiro ring include: CTU-guanamine, CMTU-guanamine, and the like.

Examples of the guanamines having an isocyanurate ring include: 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, and the like.

Examples of the urea compound include: chain urea compounds and cyclic urea compounds.

Examples of the chain urea compound include: condensates of urea such as biurea, biuret, urea formaldehyde (ホ ル ム asphyxian) and formaldehyde, and polyalkylene or arylene ureas such as polyneurylene urea.

Examples of the cyclic urea compound include: hydantoin compounds, 2-butenylidene diurea (ク ロ チ リ デ ン ジ ウ レ ア), acetylene urea, mono-, di-, tri-or tetraalkoxymethyl glycoluril such as mono-, di-, tri-or tetramethoxymethyl glycoluril, cyanuric acid, isocyanuric acid, uric acid and urazole. Examples of the hydantoin include: and metal salts such as aluminum salts of allantoin, for example, hydantoin salts of 5-methylhydantoin, 5-ethylhydantoin, 5-isopropylhydantoin, 5-phenylhydantoin, 5-benzylhydantoin, 5-dimethylhydantoin, 5-pentamethylenehydantoin, 5-methyl-5-phenylhydantoin, 5-diphenylhydantoin, 5- (o-, m-or p-hydroxyphenyl) hydantoin, 5- (o-, m-or p-aminophenyl) hydantoin, allantoin, 5-methyliallantoin, and allantoin dihydroxyaluminum salts.

Examples of the carboxylic acid hydrazide compound include: aliphatic carboxylic acid hydrazides, alicyclic carboxylic acid hydrazides, and aromatic carboxylic acid hydrazides.

Examples of the aliphatic carboxylic acid hydrazide compound include: monocarboxylic acid hydrazides such as lauric acid hydrazide, stearic acid hydrazide, 12-hydroxystearic acid hydrazide and 1,2,3, 4-butanetetracarboxylic acid hydrazide; polycarboxylic 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, dodecanedioic acid mono-or dihydrazide, hexadecanedioic acid mono-or dihydrazide, eicosanedioic acid mono-or dihydrazide, and 7, 11-octadecadien-1, 18-dihydrazide.

Examples of the alicyclic carboxylic acid hydrazide compound include: monocarboxylic acid hydrazides such as cyclohexanecarboxylic acid hydrazide; and polycarboxylic acid hydrazides such as dimer acid mono-or dihydrazide, trimer acid mono-, di-or trihydrazide, 1,2-, 1, 3-or 1, 4-cyclohexanedicarboxylic acid mono-or dihydrazide, and cyclohexanetricarboxylic acid mono-, di-or trihydrazide.

Examples of the aromatic carboxylic acid hydrazide compound include: monocarboxylic acid hydrazides such as benzoic acid hydrazide and a functional group-substituted derivative thereof, α -or β -naphthoic acid hydrazide and a functional group-substituted derivative thereof; isophthalic acid mono or dihydrazide, terephthalic acid mono or dihydrazide, 1, 4-or 2, 6-naphthalenedicarboxylic acid mono or dihydrazide, 3' -, 3,4' -or 4,4' -biphenyldicarboxylic acid mono or dihydrazide, diphenylether dicarboxylic acid mono or dihydrazide, diphenylmethane dicarboxylic acid mono or dihydrazide, diphenylethane dicarboxylic acid mono or dihydrazide, diphenyloxyethane dicarboxylic acid mono or dihydrazide, diphenylsulfone dicarboxylic acid mono or dihydrazide, diphenylketone dicarboxylic acid mono or dihydrazide, and polycarboxylic acid hydrazides such as 4,4 '-terphthalic acid mono-or dihydrazide, 4' -tetrabenzodicarboxylic acid mono-or dihydrazide, 1,2, 4-benzenetricarboxylic acid mono-, di-or trihydrazide, pyromellitic acid mono-, di-, tri-or tetrahydrazide, and 1,4,5, 8-naphthalenetetracarboxylic acid mono-, di-, tri-or tetrahydrazide. Examples of the benzoic acid hydrazide and a functional group-substituted derivative thereof include: o-, m-or p-methylbenzoic acid hydrazide, 2,4-, 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- (4' -phenyl) benzoic acid hydrazide, 4-hydroxy-3, 5-dimethylbenzoic acid hydrazide, 4-hydroxy-3, 5-di-tert-butylbenzoic acid hydrazide or the like, each of which is obtained by substituting 1 to 5 alkyl groups in the phenyl residue of phenylguanamine or the naphthyl residue of naphthylguanamine, And derivatives of functional groups such as hydroxyl, acetoxy, amino, acetamido, nitrile, carboxyl, alkoxycarbonyl, carbamoyl, alkoxy, phenyl, benzyl, cumyl, and hydroxyphenyl groups. Examples of the α -or β -naphthoic acid hydrazide and a functional group-substituted derivative thereof include: 3-hydroxy-2-naphthoic acid hydrazide, 6-hydroxy-2-naphthoic acid hydrazide, and the like.

The formaldehyde inhibitor may be used in the form of a layered material or a porous material (hydrotalcite, montmorillonite, silica gel, alumina, titanium dioxide, zirconium dioxide, sepiolite, smectite, palygorskite, imogolite, zeolite, activated carbon, or the like) supported thereon.

Among the formaldehyde inhibitors, aliphatic carboxylic acid hydrazide compounds and aromatic carboxylic acid hydrazide compounds are preferable, and aliphatic carboxylic acid hydrazide compounds are particularly more preferable.

The content of the formaldehyde inhibitor in the resin composition of the present embodiment is preferably 0.01 to 5 parts by mass, more preferably 0.01 to 2 parts by mass, and still more preferably 0.02 to 1 part by mass, relative to 100 parts by mass of the polyacetal resin (a). When the amount of the formaldehyde inhibitor to be added is within the above range, a sufficient formaldehyde-inhibiting effect can be obtained and mold deposit can be inhibited, and therefore, it is preferable.

(other Components)

The resin composition of the present embodiment may contain a conventional additive (G). The additive (G) is not particularly limited, but is preferably a stabilizer or the like used in the conventional polyacetal resin (A).

Examples of the stabilizer include: antioxidants, weathering stabilizers, and the like. Further, a trapping agent of formic acid or formaldehyde may be used. The additives may be used alone or in combination of two or more. In addition, various colorants may be contained as complementary color pigments as necessary for improving the design. Examples of the colorant include: the organic pigment and the inorganic pigment are not particularly limited, and may be a combination of one or two or more kinds of colorants.

Antioxidant agent

The antioxidant is preferably a hindered phenol-based antioxidant, and examples thereof include: octadecyl-3- (3',5' -di-tert-butyl-4 ' -hydroxyphenyl) propionate, n-octadecyl-3- (3' -methyl-5 ' -tert-butyl-4 ' -hydroxyphenyl) propionate, n-tetradecyl-3- (3',5' -di-tert-butyl-4 ' -hydroxyphenyl) propionate, 1, 6-hexanediol bis (3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate), 1, 4-butanediol bis (3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate), triethylene glycol bis (3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate), and the like.

Examples of the other hindered phenol antioxidants include: tetrakis (methylene-3- (3',5' -di-tert-butyl-4 '-hydroxyphenyl) propionate) methane, 3, 9-bis (2- (3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy) -1, 1-dimethylethyl) -2,4,8, 10-tetraoxaspiro (5.5) undecane, N' -bis [3- (3',5' -di-tert-butyl-4-hydroxyphenyl) propionyl ] hexamethylenediamine, N '-tetramethylenebis [3- (3' -methyl-5 '-tert-butyl-4-hydroxyphenyl) propionyl ] diamine, N' -bis (3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionyl) hydrazine, N-salicyloyl-N '-salicyloyl hydrazine, 3- (N-salicyloyl) amino-1, 2, 4-triazole, N' -bis (2- (3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionyloxy) ethyl) ethanediamide, and the like. Among the above hindered phenol type antioxidants, triethylene glycol di (3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate) and tetrakis (methylene-3- (3',5' -di-tert-butyl-4 ' -hydroxyphenyl) propionate) methane are preferable.

The amount of the hindered phenol-based antioxidant added is preferably 0.01 to 2 parts by mass, more preferably 0.02 to 1 part by mass, based on 100 parts by mass of the polyacetal resin (a). When the amount is 0.01 to 2 parts by mass, the thermal stability of the resin composition of the present embodiment during molding is improved, and the resin composition is excellent.

Weather-resistant stabilizer

Examples of the weather-resistant stabilizer include: hindered amine stabilizers, ultraviolet absorbers, and the like.

Examples of the hindered amine-based stabilizer include a piperidine derivative having a sterically hindered group, and examples thereof include: ester group-containing piperidine derivatives, ether group-containing piperidine derivatives, amide group-containing piperidine derivatives, high molecular weight piperidine derivative polycondensates, and the like.

Examples of the ester group-containing piperidine derivative include: 4-acetoxy-2, 2,6, 6-tetramethylpiperidine, 4-stearoyloxy-2, 2,6, 6-tetramethylpiperidine, 4-acryloyloxy-2, 2,6, 6-tetramethylpiperidine, 4-benzoyloxy-2, 2,6, 6-tetramethylpiperidine, 4-phenylcarbamoyloxy-2, 2,6, 6-tetramethylpiperidine, bis (2,2,6, 6-tetramethyl-4-piperidyl) oxalate, bis (2,2,6, 6-tetramethyl-4-piperidyl) malonate, [ [3, 5-bis (1, 1-dimethylethyl) -4-hydroxyphenyl ] methyl ] butylmalonate (1,2,2,6, 6-pentamethyl-4-piperidyl) ester, Bis (2,2,6, 6-tetramethyl-4-piperidyl) adipate, bis (N-methyl-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate, 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, bis (1,2,2,6, 6-pentamethyl-4-piperidyl) sebacate, bis (1-octyloxy-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate, bis (2,2,6, 6-tetramethyl-1-octyloxy-4-piperidyl) ester, bis (2,2,6, 6-tetramethyl-4-piperidyl) terephthalate, tris (2,2,6, 6-tetramethyl-4-piperidyl) benzene-1, 3, 5-tricarboxylate, tetrakis (1,2,2,6, 6-pentamethyl-4-piperidyl) 1,2,3, 4-butanetetracarboxylic acid, and the like.

Examples of the ether group-containing piperidine derivative include: 4-methoxy-2, 2,6, 6-tetramethylpiperidine, 4-cyclohexyloxy-2, 2,6, 6-tetramethylpiperidine, 4-phenoxy-2, 2,6, 6-tetramethylpiperidine, 4-benzyloxy-2, 2,6, 6-tetramethylpiperidine, 1, 2-bis (2,2,6, 6-tetramethyl-4-piperidinyloxy) ethane and the like.

Examples of the piperidine derivative having an amide group include: 4- (phenylcarbamoyloxy) -2,2,6, 6-tetramethylpiperidine, hexamethylene-1, 6-dicarbamate bis (2,2,6, 6-tetramethyl-4-piperidyl) ester, and the like.

Examples of the high-molecular-weight piperidine derivative polycondensate include: dimethyl succinate-1- (2-hydroxyethyl) -4-hydroxy-2, 2,6, 6-tetramethylpiperidine polycondensate, a condensate of 1,2,3, 4-butanetetracarboxylic acid and 1,2,2,6, 6-pentamethyl-4-piperidinol and tridecanol, a condensate of 1,2,3, 4-butanetetracarboxylic acid and 1,2,2,6, 6-pentamethyl-4-piperidinol and β, β, β ', β' -tetramethyl-3, 9- (2,4,8, 10-tetraoxaspiro (5.5) undecane) diethanol, and the like.

The various hindered amine stabilizers may be used singly or in combination of two or more.

Among them, preferred hindered amine-based stabilizers are bis (1,2,2,6, 6-pentamethyl-4-piperidyl) sebacate, bis (N-methyl-2, 2,6, 6-tetramethyl-4-piperidyl) sebacate, bis (2,2,6, 6-tetramethyl-4-piperidyl) sebacate, 1,2,3, 4-butanetetracarboxylic acid and a condensate of 1,2,2,6, 6-pentamethyl-4-piperidinol and β, β, β ', β' -tetramethyl-3, 9- (2,4,8, 10-tetraoxaspiro (5.5) undecane) diethanol.

The content of the hindered amine-based stabilizer is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 2 parts by mass, and still more preferably 0.1 to 1.5 parts by mass, relative to 100 parts by mass of the polyacetal resin (a).

The resin composition of the present embodiment preferably further contains an ultraviolet absorber as the weather-resistant stabilizer. As a result, the molded article obtained from the resin composition of the present embodiment has an effect of improving weather resistance (light stability). Examples of the ultraviolet absorber include: benzotriazole compounds, benzophenone compounds, oxalic anilide compounds and hydroxyphenyl-1, 3, 5-triazine compounds.

Examples of the benzotriazole compound include: 2- (2' -hydroxy-5 ' -methylphenyl) benzotriazole, 2- (2' -hydroxy-3 ',5' -di-tert-butylphenyl) benzotriazole, 2- (2' -hydroxy-3 ',5' -di-tert-pentylphenyl) benzotriazole, 2- (2' -hydroxy-3 ',5' -diisopentylphenyl) benzotriazole and the like having a hydroxyl group and an alkyl group (preferably C)_1-6Alkyl) substituted aryl benzotriazoles; 2- [2' -hydroxy-3 ',5' -bis (alpha, alpha-dimethylbenzyl) phenyl]Benzotriazoles having a hydroxyl group and an aralkyl or aryl substituted aryl group such as benzotriazole; having a hydroxyl group such as 2- (2 '-hydroxy-4' -octyloxyphenyl) benzotriazoleAnd alkoxy (preferably C)_1-12Alkoxy) substituted aryl benzotriazoles; and the like. The preferred benzotriazole compound is a compound having a hydroxyl group and C_3-6Alkyl substituted C_6-10Benzotriazoles of aryl radicals, especially phenyl radicals, and compounds having hydroxy and C_6-10aryl-C_1-6Alkyl (especially phenyl-C)_1-4Alkyl) substituted aryl benzotriazoles.

Examples of the benzophenone compound include: benzophenones having a plurality of hydroxyl groups; having hydroxy and alkoxy groups (preferably C)_1-16Alkoxy) benzophenones; and the like.

Examples of benzophenones having a plurality of hydroxyl groups include: di-, tri-or tetrahydroxybenzophenones such as 2, 4-dihydroxybenzophenone; benzophenones having a hydroxyl group and a hydroxyl-substituted aryl or aralkyl group such as 2-hydroxy-4-benzyloxybenzophenone; and the like.

Further, as benzophenones having a hydroxyl group and an alkoxy group, for example, there can be mentioned: 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octyloxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2' -dihydroxy-4-methoxybenzophenone, 2' -dihydroxy-4, 4' -dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone and the like. Preferred benzophenone compounds are compounds having hydroxyl and hydroxyl substituted C_6-10Aryl or C_6-10aryl-C_1-4Alkyl benzophenones, in particular, those having hydroxy and hydroxy-substituted phenyl groups C_1-2Alkyl benzophenones.

Examples of the oxalic anilide compound include: n- (2-ethylphenyl) -N '- (2-ethoxy-5-tert-butylphenyl) oxalic acid diamide, N- (2-ethylphenyl) -N' - (2-ethoxy-phenyl) oxalic acid diamide, and the like.

Examples of the hydroxyphenyl-1, 3, 5-triazine compound include: 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-4-hexyloxyphenyl) -1,3, 5-triazine, 2, 4-diphenyl-6- (2-hydroxy-4-octyloxyphenyl) -1,3, 5-triazine, 2, 4-diphenyl-6- (2-hydroxy-4-dodecyloxyphenyl) -1,3, 5-triazine and the like.

Among the compounds as the ultraviolet absorber, a benzotriazole-based compound is preferable, and 2- [2' -hydroxy-3 ',5' -bis (. alpha.,. alpha. -dimethylbenzyl) phenyl ] benzotriazole is more preferable.

The amount of the ultraviolet absorber added is preferably 0.1 to 5 parts by mass, more preferably 0.1 to 2 parts by mass, and still more preferably 0.1 to 1.5 parts by mass, based on 100 parts by mass of the polyacetal resin (a).

When the resin composition of the present embodiment contains an ultraviolet absorber and a hindered amine stabilizer, the mass ratio of the hindered amine stabilizer to the ultraviolet absorber is preferably 10/90 to 80/20, more preferably 10/90 to 70/30, and still more preferably 20/80 to 60/40 in terms of ultraviolet absorber/hindered amine stabilizer (mass ratio).

Capture agent for formic acid or formaldehyde

In the resin composition of the present embodiment, the above-mentioned scavenger for formic acid or formaldehyde is preferably used. Examples of the trapping agent for formic acid or formaldehyde include: formaldehyde-reactive nitrogen-containing compounds and polymers, fatty acid calcium salts, alkali or alkaline earth metal hydroxides, inorganic acid salts, carboxylates or alkoxides, and the like.

Examples of the formaldehyde-reactive nitrogen-containing compound include: dicyandiamide, amino-substituted triazines, cocondensates of amino-substituted triazines with formaldehyde, and the like.

Examples of the amino-substituted triazine include: melamine, guanamine (2, 4-diamino-s-triazine), melamine (2,4, 6-triamino-s-triazine), N-butylmelamine, N-phenylmelamine, N-diphenylmelamine, N-diallylmelamine, N ', N "-triphenylmelamine, N-methylolmelamine, N ' -dimethylolmelamine, N ', N" -trimethylolmelamine, phenylguanamine (2, 4-diamino-6-phenyl-s-triazine), and the like. In addition, there may be mentioned: 2, 4-diamino-6-methyl-s-triazine, 2, 4-diamino-6-butyl-s-triazine, 2, 4-diamino-6-benzyloxy-s-triazine, 2, 4-diamino-6-butoxy-s-triazine, 2, 4-diamino-6-cyclohexyl-s-triazine, 2, 4-diamino-6-chloro-s-triazine, 2, 4-diamino-6-mercapto-s-triazine, 2, 4-dihydroxy-6-amino-s-triazine (ammelide), 2-hydroxy-4, 6-diamino-s-triazine (ammelide), N, N, N ', N' -tetracyanoethylphenylguanamine, and the like.

Examples of the cocondensate of the amino-substituted triazine with formaldehyde include: melamine-formaldehyde polycondensates, and the like.

Among them, dicyandiamide, melamine and melamine-formaldehyde polycondensates are preferable.

Examples of the polymer having formaldehyde-reactive nitrogen include: polyamide resins, polymers obtained by polymerizing acrylamide and derivatives thereof or acrylamide and derivatives thereof with other vinyl monomers in the presence of metal alkoxides, polymers obtained by polymerizing acrylamide and derivatives thereof or acrylamide and derivatives thereof with other vinyl monomers in the presence of a radical polymerization initiator, nitrogen atom-containing polymers such as amines, amides, ureas, and carbamates, and the like.

Examples of the polyamide resin include: nylon 4-6, nylon 6-10, nylon 6-12, nylon 12, and copolymers thereof such as nylon 6/6-6, nylon 6/6-6/6-10, nylon 6/6-12, and the like.

Examples of the polymer obtained by polymerizing acrylamide and derivatives thereof or acrylamide and derivatives thereof with other vinyl monomers in the presence of a metal alkoxide include poly- β -alanine copolymers. These polymers or copolymers can be produced by the methods described in Japanese patent publication No. 6-12259 (U.S. Pat. No. 5015707), Japanese patent publication No. 5-87096, Japanese patent publication No. 5-47568 and Japanese patent application laid-open No. 3-234729.

Examples of the fatty acid calcium salt include calcium salts of saturated or unsaturated fatty acids having 10 to 36 carbon atoms, and the calcium salts may be substituted with a hydroxyl group. Examples of the saturated fatty acid include: capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, tetracosanoic acid, cerotic acid, montanic acid, melissic acid, and triacontanoic acid. Examples of the unsaturated fatty acid include: undecylenic acid, oleic acid, elaidic acid, docosenoic acid, erucic acid, brassidic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, and stearolic acid. Among these fatty acids, palmitic acid, stearic acid, and 12-hydroxystearic acid are particularly preferable.

Examples of the hydroxide, inorganic acid salt, carboxylate or alkoxide of the alkali metal or alkaline earth metal include: hydroxides of sodium, potassium, magnesium, calcium, barium, etc., carbonates, phosphates, silicates, borates, carboxylates of the above metals. The carboxylic acid salt is not the above-mentioned fatty acid calcium salt. Examples of the carboxylic acid corresponding to the carboxylate include saturated fatty acids or unsaturated fatty acids having 10 to 36 carbon atoms, and these carboxylic acids may be substituted with a hydroxyl group. Examples of the saturated aliphatic carboxylic acid include: capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, tetracosanoic acid, cerotic acid, montanic acid, melissic acid, and triacontanoic acid. Examples of the unsaturated aliphatic carboxylic acid include: undecylenic acid, oleic acid, elaidic acid, docosenoic acid, erucic acid, brassidic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, and stearolic acid. Examples of the alkoxide include a methoxide and an ethoxide of the above metal.

The amount of each of the formaldehyde-reactive nitrogen-containing compound and the polymer, the fatty acid calcium salt, the alkali metal or alkaline earth metal hydroxide, the inorganic acid salt, the carboxylate, or the alkoxide as the scavenger of formic acid or formaldehyde is preferably in the range of 0.01 to 1 part by mass, more preferably 0.02 to 0.5 part by mass, based on 100 parts by mass of the polyacetal resin. When the amount is 0.01 to 1 part by mass, the resin composition of the present embodiment can improve thermal stability during molding, reduce the amount of formaldehyde generated from a molded article, and improve heat aging resistance.

Examples of the organic pigment include: phthalocyanine pigment, condensed azo pigment, azo lake pigment, quinacridone pigment, and perylene

Oxazine pigments, isoindolinone pigments, fused polycyclic pigments, and the like.

Examples of the inorganic pigment include: zinc white, titanium dioxide, red iron oxide, chromium oxide, iron black and other simple oxides, cadmium yellow, cadmium orange, cadmium red and other sulfides, chromium yellow, zinc yellow, molybdenum-chromium red and other chromates, iron blue and other ferrocyanides, ultramarine blue and other silicates, carbon black and the like.

The amount of the colorant added is preferably 0.0001 to 2 parts by mass, more preferably 0.0005 to 1 part by mass, per 100 parts by mass of the polyacetal resin (A). By setting the amount of the colorant to be added within the above range, the effect of improving the design can be obtained without promoting the reduction of the mechanical strength of the molded article, particularly the generation of formaldehyde from the polyacetal resin (a).

The resin composition of the present embodiment may further contain various inorganic fillers, other thermoplastic resins, softeners, crystal nucleating agents, mold release agents, and the like, which have been conventionally used, as necessary, within a range not to impair the object of the present invention.

(production method)

The resin composition of the present embodiment can be obtained by, for example, melting and mixing a part of the above-described raw materials using a commonly used melt kneader. Examples of the melt-kneading machine include a kneader, a roll mill, a single-screw extruder, a twin-screw extruder, and a multi-screw extruder.

The temperature for melt-kneading may be selected depending on the melting point or softening point of the polyacetal resin (A) to be used, and the temperature for melt-kneading is preferably a temperature 1 to 100 ℃ higher than the melting point or softening point of the polyacetal resin (A), more preferably a temperature 10 to 60 ℃ higher than the melting point or softening point of the polyacetal resin (A), and still more preferably a temperature 20 to 50 ℃ higher than the melting point or softening point of the polyacetal resin (A). The melting point or softening point can be determined by a Differential Scanning Calorimetry (DSC) method according to JIS K7121. In order to maintain quality and working environment, it is preferable to replace the inside of the system with an inert gas or to degas the inside with one-stage or multi-stage exhaust ports.

In the first embodiment of the present invention, in the case where the polyacetal resin (a) is in the form of pellets, in order to uniformly maintain the dispersion state of each component including the metal particles (B) in the polyacetal resin (a), it is preferable to use an additive (a stackers) as necessary, to mix the components after adding a stabilizer (an antioxidant, a scavenger of formaldehyde or formic acid, a weather-resistant stabilizer, a scavenger of formaldehyde, or the like) in advance, and then to mix the metal particles (B), the polyalkylene glycol compound (C), and the lubricant (E) as necessary, and then to melt-knead the mixture.

In the case where the polyacetal resin (A) is in the form of pellets, it is preferable that a part or all of the pellets are pulverized to be in the form of a powder, and if necessary, a stabilizer (an antioxidant, a scavenger of formaldehyde or formic acid, a weather-resistant stabilizer, a scavenger of formaldehyde, or the like) is mixed with the polyacetal resin (A) in the form of a powder using an admixture, followed by mixing (B) the metal particles, (C) the polyalkylene glycol compound, and if necessary, (E) a lubricant, and then melt-kneading.

In the second embodiment of the present invention, in the case where the polyacetal resin (a) is in the form of particles, it is preferable to mix the components containing the metallic pigment (D) in the polyacetal resin (a) after adding additives (an antioxidant, a scavenger for formaldehyde or formic acid, a weather-resistant stabilizer, a scavenger for formaldehyde, etc.) in advance, if necessary, using an admixture, and then to mix the metallic pigment (D) and the lubricant (E) if necessary, and then to melt-knead the mixture, in order to uniformly maintain the dispersed state of the components in the polyacetal resin (a).

When the polyacetal resin (a) is in the form of particles, it is preferable that a part or all of the particles are pulverized to be in the form of powder, and if necessary, a stabilizer (an antioxidant, a scavenger for formaldehyde or formic acid, a weather-resistant stabilizer, a scavenger for formaldehyde, or the like) is mixed with the polyacetal resin (a) in the form of powder using an admixture, followed by mixing (D) the metallic pigment and, if necessary, (E) the lubricant, and then melt-kneading.

In the present embodiment, examples of the external additive include: aliphatic hydrocarbons, aromatic hydrocarbons, modified products thereof, mixtures thereof (liquid paraffin, mineral spirits, etc.), fatty acid esters of polyhydric alcohols, and the like. In addition, in the sense of preventing damage to (B) the metal particles or (D) the metal pigment in the blending step, it is preferable to blend in a post-step.

In the case where the metal pigment (D) is contained in the resin composition as in the resin composition of the second embodiment, a part of the polyalkylene glycol compound (C) in the metal pigment (D) may be separated from the metal particles (B) in the metal pigment (D) and dispersed in the resin composition (for example, may be separated and dispersed at the time of melt-kneading of the respective components).

In addition, in the production of the resin composition of the present embodiment, the polyacetal resin (a) and the stabilizer (at least one selected from the group consisting of an antioxidant, a scavenger of formaldehyde or formic acid, and a weather-resistant stabilizer) may be previously subjected to pre-melt kneading. For this preliminary kneading, a commonly used melt kneader can be used. The temperature for melt kneading is selected in accordance with the melting point or softening point of the polyacetal resin (A) to be used. The temperature is preferably 1 to 100 ℃ higher than the melting point or softening point of the polyacetal resin (A), more preferably 10 to 60 ℃ higher than the melting point or softening point of the polyacetal resin (A), and still more preferably 20 to 50 ℃ higher than the melting point or softening point of the polyacetal resin (A). Examples of the melt-kneading machine include: kneading machines, roll mills, single-screw extruders, twin-screw extruders and multi-screw extruders. In order to maintain quality and working environment, it is preferable to replace the inside of the system with an inert gas or to degas the inside with one-stage or multi-stage exhaust ports.

(molded body)

The resin composition of the present embodiment can be molded to produce a molded article.

Examples of the method for producing the molded article include known molding methods such as extrusion molding, injection molding, vacuum molding, blow molding, injection compression molding, decoration molding, gas-assisted injection molding, foaming injection molding, low-pressure molding, ultra-thin wall injection molding (ultra-high-speed injection molding), and in-mold composite molding (insert molding ). In particular, from the viewpoints of quality, production stability, economy and the like, injection molding, injection compression molding, and a molding method combining them with in-mold composite molding are preferable.

Further, by bonding the resin composition of the present embodiment to various resins including rubber and/or an elastomer (ultrasonic bonding, high-frequency bonding, hot plate bonding, hot press molding, multilayer injection molding, multilayer blow molding, and the like), a molded article having 2 or more layers having desired characteristics and appearance can be produced. Thus, excellent properties (impact resistance, sliding property, chemical resistance, etc.) of each resin can be imparted, and a molded article having an appearance with excellent design can be obtained.

(characteristics)

The resin composition of the present embodiment has good retention stability during molding and extrusion, is less in appearance defects, is less in volatilization of an organic solvent from the resin composition, and can give a molded article having an excellent metallic tone appearance, high glossiness and FI value, and an aesthetically pleasing and excellent metallic tone appearance.

The amount of formaldehyde generated by the resin composition of the present embodiment is preferably 5mg/kg or less, and more preferably 3mg/kg or less.

The formaldehyde emission can be measured by the method described in the examples described below.

The FI value of the resin composition of the present embodiment is preferably 13 or more, and more preferably 14 or more. The FI value can be measured by the method described in the examples described later.

Here, a phenomenon in which lightness varies with a change in observation angle is referred to as a flop (F/F) phenomenon, and a quantitative value representing the phenomenon is referred toThe value is called the FI (dynamic exponent) value. The FI value may be calculated from the lightness (L) at 15 degrees, 45 degrees and 110 degrees using the formula first proposed by DuPont (DuPont)_15°、L*_45°And L_110°) Values were determined (A.B.J.Rodriguez, JOCCA, (1992(4)), p.150 to 153). Specifically, the FI value is obtained by the following equation, and the higher the FI value, that is, the larger the difference between the lightness (L ×) in the highlight direction (the regular reflection direction with respect to the incident angle of light) and the shadow direction (the non-regular reflection direction), the higher the metallic feeling is generally perceived.

The gloss of the resin composition of the present embodiment immediately after injection molding is preferably 60 or more, and more preferably 70 or more. Further, it is preferable that the gloss after standing for 48 hours in an environment of 80 ℃ and 90% humidity is reduced from the gloss immediately after injection molding to a small extent.

The gloss can be measured by the method described in the examples described later.

Here, the glossiness is one of the indicators of the metallic tone appearance. The glossiness depends on the smoothness of the surface of the molded article, and a metallic material molded by kneading a bright material such as a metallic pigment generally tends to have a reduced glossiness. When the glossiness is lowered, the lightness, FI value, and the like are lowered due to the influence of scattering of reflected light on the surface of the molded article, and the quality of the metallic tone appearance tends to be lowered.

In addition, as a conventional method for improving the gloss, there are increasing cases of dealing with the hardware aspect, such as a method of raising the mold temperature or a heating and cooling method (ヒ ー ト ア ン ド ク ー ル method) which is increasingly used in recent years. In view of the above-mentioned problems of the prior art, the present inventors have found that a resin composition and a molded article having excellent metallic appearance and metallic appearance, which are excellent in retention stability during molding and extrusion, less in appearance defects when molded articles are produced, and less in volatilization of an organic solvent from the resin composition, can be obtained by adding a specific (C) polyalkylene glycol compound.

(use)

The molded article of the resin composition of the present embodiment can be used for, in particular, internal and external parts having a mechanism part or a sliding part. For example, the present invention is used as any one member selected from the group consisting of office automation equipment, music, video, information equipment, and communication equipment, industrial members provided in office furniture and home equipment, and members for use in and out of automobiles. In particular, it is suitable for use as any one member selected from the group consisting of a handle, a switch and a button, which requires excellent appearance. In addition, in order to use the molded article obtained from the resin composition of the present embodiment as an appearance member, an effect of improving the appearance is preferably exhibited when an embossing die (シ ボ gold type) is used at the time of molding or when an appearance design surface is imparted by embossing (シ ボ processing) the molded article.

Further, according to the resin composition of the present embodiment, a molded article having metallic luster without plating, coating, or other processing on the surface, excellent thermal stability and weather resistance, good mechanical properties (e.g., tensile properties and impact strength), high glossiness and FI value, and good appearance properties can be obtained. Further, since the molded article obtained from the resin composition of the present embodiment has good appearance characteristics as described above, it can have a practically good appearance without being coated. Therefore, an appearance excellent in design can be effectively obtained without using a solvent. The resin composition of the present embodiment is excellent in production stability, can be produced in a good working environment, and is also excellent in cost and environment.