JP2020007528A - Resin composition - Google Patents

Abstract

To provide a resin composition capable of manufacturing a molded article less in generation of formaldehyde and having excellent metal tone appearance.SOLUTION: The resin composition contains (A) a polyacetal resin of 100 pts.mass, (B) a metal particle having volume average particle diameter of 3 to 40 μm and average particle thickness of 0.03 to 0.4 μm of 0.1 to 10 pts.mass, and (C) a polyalkylene glycol compound with percentage of mass of an oxygen atom of 1 to 36% of 0.01 to 5 pts.mass. The resin composition contains: (A) the polyacetal resin of 100 pts.mass; and (D) metallic pigment of 0.1 to 15 pts.mass containing (B) the metal article having volume average particle diameter of 3 to 40 μm and average particle thickness of 0.03 to 0.4 μm, and (C) the polyalkylene glycol compound with percentage of mass of an oxygen atom of 1 to 36%.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a resin composition.

  Crystalline resins have many useful features, such as the presence of crystals in which molecular chains are regularly arranged, high mechanical strength and rigidity, and excellent chemical resistance. Since the crystalline resin is easy to process, it has been widely used in the past mainly for mechanical parts and sliding parts in precision equipment, home appliances, OA equipment, automobiles, industrial materials, miscellaneous goods and the like. .

  In addition, for the purpose of imparting a characteristic metallic luster called a metallic tone to various resins, metallic coloring composed of metal particles represented by flaky aluminum powder (hereinafter also referred to as “aluminum flakes”) is used. Incorporation of pigments has been performed. Resin compositions containing such metallic coloring pigments are used for interior and exterior parts of automobiles, personal computer housings, and the like.

  As such a resin composition, for example, resin compositions described in the following patent documents are known.For example, by molding a resin containing a gloss pigment, a metallic luster is developed to enhance the design. Attempts have been made to grant. Specifically, Patent Literature 1 and Patent Literature 2 disclose molded articles made of a synthetic resin composition containing a specific metallic pigment. Patent Document 3 proposes a polyacetal resin composition containing a weathering agent, aluminum particles having a specific particle size, a particle size distribution, and a particle thickness, and a specific fatty acid. It discloses excellent properties, mechanical properties, molded appearance, weld performance, and brightness. Patent Document 4 proposes a polyacetal resin composition containing a polyacetal resin, a metallic coloring pigment, and a specific liquid additive. The composition has extrusion characteristics, retention stability during molding, and appearance. It is disclosed that it has excellent characteristics, the content of the organic solvent is reduced, and a metallic appearance is imparted. Further, Patent Document 5 includes a polyacetal resin, a metal pigment, and an ultraviolet stabilizer, and the metal pigment and the ultraviolet stabilizer are of such a degree that the glossiness of the outer surface of the obtained molded article becomes a certain level or more. Disclosed are polymer compositions that are present in a sufficient amount dispersed.

JP-A-62-020574 JP-A-61-159453 JP 2010-065210 A JP 2009-155418 A WO 2013/49541

However, when the methods described in Patent Literatures 1 and 2 are used for polyacetal resins, heat generation during melt mixing and the influence of active points on the metal surface reduce the amount of formaldehyde generation and the appearance of products such as glossiness. Regarding improvement, sufficient effects have not been obtained.
Further, the technology disclosed in Patent Document 3 does not examine the effect on the amount of formaldehyde generated, the effect on the appearance such as the glossiness of a product, and the like.
Patent Literature 4 proposes a technique aiming at thermal stability of a molded article and suppression of formaldehyde generation, but discloses a metallic pigment in which aluminum powder is dispersed in polyethylene. No effect on the appearance such as glossiness and luminance of the obtained molded article has been studied, and no sufficient effect has been obtained on these.
Patent Literature 5 does not mention at all the effects of other additives on glossiness and the like.

  Accordingly, an object of the present invention is to provide a resin composition which produces a small amount of formaldehyde and at the same time can produce a molded article having an excellent metallic appearance.

  The present inventors have conducted intensive studies and found that the polyacetal resin has a specific mass ratio of a metal particle having a specific shape and a polyalkylene glycol compound having a specific range in which the mass ratio of oxygen atoms to the total mass of the compound is a specific range. It has been found that the addition of (1) to (4) gives a resin composition having little formaldehyde emission and at the same time having an excellent metallic appearance, and has completed the present invention.

[1]
(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;
(C) 0.01 to 5 parts by mass of a polyalkylene glycol compound having a mass ratio of oxygen atoms to the mass of the entire compound of 1 to 36%,
A resin composition comprising:
[2]
(A) 100 parts by mass of a polyacetal resin,
(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) the ratio of the mass of oxygen atoms to the total mass of the compound is 1 (D) 0.1 to 15 parts by mass of a metal pigment containing a polyalkylene glycol compound which is
A resin composition comprising:
[3]
The resin composition according to [2], wherein a ratio of the (B) metal particles contained in the (D) metal pigment is 70 to 95% by mass.
[4]
The resin composition according to any one of [1] to [3], wherein the (C) polyalkylene glycol compound has a number average molecular weight of 500 to 10,000.
[5]
The resin composition according to any one of [1] to [4], wherein the (C) polyalkylene glycol compound has a repeating unit derived from an oxyalkylene having 4 or more carbon atoms.
[6]
The resin composition according to any one of [1] to [5], wherein the (B) metal particles include aluminum.
[7]
The resin composition according to any one of [1] to [6], further comprising (E) a lubricant.

  ADVANTAGE OF THE INVENTION According to this invention, the generation of a formaldehyde is small, and the resin composition which can manufacture the molded article which has excellent metal appearance at the same time can be provided.

It is a schematic diagram explaining the evaluation method of FI value in an example.

  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 can be implemented with various modifications within the scope of the gist.

[Resin composition]
The resin composition of the first aspect in the present embodiment comprises (A) 100 parts by mass of a polyacetal resin, (B) a volume average particle diameter of 3 to 40 μm, and an average particle thickness of 0.03 to 0.4 μm. 0.1 to 10 parts by mass of metal particles and (C) 0.01 to 5 parts by mass of a polyalkylene glycol compound having a mass ratio of oxygen atoms to the entire compound of 1 to 36%. .
The resin composition according to the second aspect of the present embodiment comprises (A) 100 parts by mass of a polyacetal resin, (B) a volume average particle diameter of 3 to 40 μm, and an average particle thickness of 0.03 to 0.4 μm. (D) 0.1 to 15 parts by mass of a metal particle and (D) a metal pigment containing a polyalkylene glycol compound in which the mass ratio of oxygen atoms to the mass of the entire compound is 1 to 36%. Including.
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” are referred to as “(B) metal particles” and “(C) compound”. The polyalkylene glycol compound in which the mass ratio of oxygen atoms to the entire mass is 1 to 36% is referred to as “(C) polyalkylene glycol compound” and “(B) the volume average particle diameter is 3 to 40 μm, (D) including metal particles having a particle thickness of 0.03 to 0.4 μm and a polyalkylene glycol compound having a mass ratio of oxygen atoms to the total mass of the compound of 1 to 36%. The “metal pigment” is also referred to as “(D) metal pigment”.

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

(A) As the polyacetal resin, a polyoxymethylene homopolymer substantially composed of oxymethylene units — (CH ₂ O) — obtained by homopolymerization of a cyclic oligomer such as formaldehyde, trioxane or tetraoxane, or formaldehyde and / or trioxane When a cyclic ether and / or cyclic formal or hindered phenolic antioxidant obtained by copolymerization of 500 ppm by mass or less the added cyclic formal least 1 mass ppm, oxymethylene units - (CH ₂ O) And polyoxymethylene copolymers having a structure in which an oxyalkylene unit represented by the following general formula (1) is randomly inserted into a chain consisting of:

（式中のＲ₁及びＲ₂は、それぞれ水素原子、アルキル基、又はアリール基であり、それらは同一であっても異なっていてもよく、ｎは２〜６の整数である）

(R ₁ and R ₂ in the formula are each a hydrogen atom, an alkyl group, or an aryl group, which may be the same or different, and 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 with a heterogeneous component block containing 50% by mass or more of oxymethylene repeating units. It is.

Further, the insertion ratio of the oxyalkylene unit in the polyoxymethylene copolymer is preferably from 0.01 mol to 50 mol, more preferably from 0.03 mol to 20 mol, per 100 mol of the oxymethylene unit. is there. Examples of the oxyalkylene unit include an oxyethylene unit, an oxypropylene unit, an oxytetramethylene unit, an oxybutylene unit, and an oxyphenylethylene unit. Among these oxyalkylene units, an oxypropylene unit-[(CH ₂ ) ₃ O]-and an oxytetramethylene unit-[(CH ₂ ) ₄ O]-are preferable from the viewpoint of improving the physical properties of the resin composition. .

It is desirable that the terminal of the polyacetal resin obtained by the homopolymerization or the copolymerization be stabilized. Examples of the method of stabilizing the terminal include a method of esterifying, etherifying, and urethane-forming a terminal hydroxyl group, a method of stabilizing an unstable terminal portion by hydrolysis, and the like.
The polyacetal resin subjected to the terminal stabilization treatment is, for example, a polyoxymethylene copolymer obtained by copolymerization of formaldehyde and / or trioxane with a cyclic ether and / or cyclic formal, and a molecular terminal stabilization treatment immediately after the polymerization. And then injecting and kneading water or alcohol or a mixture thereof in a molten state, and performing a devolatilizing step of releasing vapor and free formaldehyde of the hydroxyl-containing compound such as the injected water. It is obtained by, for example, continuously supplying to a different-direction rotating non-intermeshing type twin screw extruder for processing. In addition, when injecting and kneading the above-mentioned water or alcohol, or a mixture thereof, it is preferable to add a basic substance such as triethylamine as a pH adjuster.

  The MFR (melt flow rate; based on ASTM D57E, temperature condition: 190 ° C.) of the polyacetal resin is preferably from 2.5 to 40 g / 10 minutes, more preferably from 3 to 30 g / 10 minutes. By adjusting the MFR to the above range, the balance between the mechanical properties of the resin composition, the thermal stability during the stay molding, and the amount of formaldehyde generated is improved.

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

((B) metal particles)
(B) The metal particles have a flat shape such as a coin shape or a flake shape, and preferably have a volume average particle diameter (D50) of 3 to 40 μm and an average particle thickness of 0.03 to 0.4 μm. .
(B) The metal particles can be used alone or in combination of two or more.

(B) As a material constituting the metal particles, known and commonly used metal particles can be used. Among them, from the viewpoints of high reflectance, easy availability, and high processing flexibility, (B) The metal particles preferably contain aluminum, and more preferably contain only aluminum.
(B) When using aluminum particles as metal particles, it is preferable to have a moderate oxide film on the surface. By having an appropriate oxide film, a high reflectance specific to aluminum can be maintained, and the corrosion resistance and temporal stability of the metal particles can be maintained.
Further, when aluminum particles are used as the metal particles (B), the purity is not particularly limited, but other metals may be contained as impurities or alloy components as long as the effects of the present invention are not impaired. Examples of the impurities or alloy components include Si, Fe, Cu, Mn, Mg, Zn, and the like.

(B) The metal particles can be produced by a known method. For example, atomized powder, cutting powder, foil powder, vapor-deposited powder, metal powder obtained by other methods, preliminarily selected by primary classification and the like, in the presence of a grinding medium containing a grinding aid and a solvent, a ball mill, It is obtained by wet pulverizing treatment with an attritor, a planetary mill, a vibration mill or the like, classifying the mixture under a wet condition with a sieve, followed by solid-liquid separation using a filter press or the like. This makes it possible to produce (B) metal particles having a small number of uneven fracture surfaces existing at the ends of the flakes.
If the pulverizing medium used here is excessively added, the oxygen content in the particles increases, so it is preferable to reduce the pulverizing medium as much as possible.

(B) The shape of the metal particles is preferably a flat shape such as a coin shape or a flake shape. The term “flat shape” as used herein refers to a material having an average shape ratio [average particle thickness (t) / volume average particle diameter (D ₅₀ )] of 0.2 or less, and preferably 0.1 or less. And more preferably 0.05 or less. By setting the average shape ratio in this range, the surface area of a portion having a high reflectance specific to a metal can be increased by adding a small amount of (B) metal particles. The brightness of the molded body can be efficiently increased.

In the first aspect of the present embodiment, the content of the metal particles (B) is 0.1 to 10 parts by mass, preferably 1 to 8 parts by mass, based on 100 parts by mass of the polyacetal resin. Preferably it is 1.5 to 7 parts by mass, particularly preferably 2 to 6 parts by mass.
By adjusting the content of the metal particles to the above range, in the molded article of the resin composition of the present embodiment, the rigidity and impact resistance, which are the mechanical properties inherent to the polyacetal resin, are more favorably maintained, and formaldehyde is generated. And a good metallic luster can be exhibited.

(B) The volume average particle diameter (D ₅₀ ) of the metal particles needs to be 3 to 40 μm as described above, but is preferably 4 μm or more, more preferably 5 μm or more, and 35 μm or less. And more preferably 30 μm or less. (B) When the volume average particle diameter (D ₅₀ ) of the metal particles is in the range of ₅ to 15 μm, the effect of suppressing the generation of formaldehyde is particularly large. On the other hand, in the range of 15 to 30 μm, the glossiness is low. It is particularly preferable because the improvement effect is particularly large.
The volume average particle diameter (D ₅₀ ) can be measured by the method described in Examples described later.

(B) The average particle thickness (t) of the metal particles needs to be 0.03 to 0.4 μm as described above, but is preferably 0.08 μm or more, and more preferably 0.10 μm or more. More preferably, it is more preferably 0.12 μm or more, more preferably 0.39 μm or less, more preferably 0.38 μm or less, and even more 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 of Calculating from Water Surface Diffusion Area (WCA) First, (B) a constituent component (for example, aluminum) of metal particles is pre-treated with a mineral spirit solution of 5% stearic acid, and then JIS K5906-1991. The water surface diffusion area (WCA) of the component (B) of the metal particles is measured according to the following. Next, it can be calculated by the following equation using the water surface diffusion area (WCA) (m ² / g) per 1 g of the component obtained by the measurement.
t = 0.4 / WCA (when the component of (B) metal particles is aluminum)
The method of calculating the above average particle thickness is described, for example, in Aluminum Paint and Powder, JD Edwards & RIWray, 3rd edition, Reinhold Publishing Corp. New York (1955), pp. 16-22. Further, “0.4” in the above formula is the reciprocal (1 / 2.7 = about 0.4) of the density of aluminum of 2.7 g / cm ³ .
The method of measuring the water surface diffusion area described in JIS is for the leafing type, whereas aluminum (aluminum pigment) is of the non-leafing type. However, the method of measuring the water surface diffusion area (WCA) of aluminum is the same as the leafing type described in JIS K5906-1991 except that the sample for measurement is pretreated with a mineral spirit solution of 5% stearic acid. The same can be done. Preliminary treatment of the sample is described in Hourly Coating Materials, No. 156, pp. 2-16 (198.9.1 issued by Asahi Kasei Kogyo Co., Ltd.).

2) Method of Calculating from Scanning Electron Microscope (SEM) Observation Results When the calculation cannot be performed by the method of 1) above (for example, when WCA cannot be measured), (B) the metal particles are scanned with a scanning electron microscope (SEM). ), The average value can be calculated from the thickness of the metal particles (B) observed at 100 places, for example.

By using the (B) metal particles having the volume average particle diameter (D ₅₀ ) and the average particle thickness (t) in the above ranges, it is possible to prevent the metal particles from being broken at the time of extrusion processing and the like, and It becomes possible to express excellent appearance characteristics and good metallic luster to a molded article produced from the resin composition.

((C) polyalkylene glycol compound)
(C) In the polyalkylene glycol compound, the ratio of the mass of the oxygen atom to the mass of the entire compound is in the range of 1 to 36%.
In the first aspect of the present embodiment, the content of (C) the polyalkylene glycol compound is 0.01 to 5 parts by mass, and preferably 0.05 to 4 parts by mass, based on 100 parts by mass of the polyacetal resin. And more preferably 0.1 to 2 parts by mass, particularly preferably 0.2 to 1 part by mass.
In the first aspect of the present embodiment, 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, and more preferably 2 to 50 parts by mass. The amount is 40 parts by mass, more preferably 3 to 30 parts by mass, particularly preferably 5 to 15 parts by mass.
By adjusting the content of the polyalkylene glycol compound in the above range, in the molded article of the resin composition of the present embodiment, it is possible to sufficiently exert the effect of improving the glossiness and to suppress the generation of formaldehyde. It becomes possible.
In the present embodiment, the polyalkylene glycol compound (C) can be used alone or in combination of two or more.

In the present embodiment, as the polyalkylene glycol compound (C), homopolymers, copolymers, esterified derivatives of polyalkylene glycol, and other polyalkylene glycol-modified alkylene glycols (for example, C _3-6 alkylene glycol) Body and the like. As specific examples, for example, homopolymers include polypropylene glycol, polytetramethylene ether glycol, polypentamethylene ether glycol, polyneopenthylene ether glycol, and the like, and copolymers include polyethylene polytetramethylene ether Copolymer, Polypropylene polytetramethylene ether copolymer, Polyethylene polypentamethylene ether copolymer, Polypropylene polypentamethylene ether copolymer, Polyethylene poly neopentylene ether copolymer, Polypropylene poly neopentylene ether copolymer , THF-neopentyl glycol copolymer and the like, and examples of esterified derivatives of 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, polyneopenthylene ether glycol monostearate , Polyneopenthylene ether glycol distearate, and the like. Among these, polypropylene glycol, polytetramethylene ether glycol, and THF-neopentyl glycol copolymer are preferable, and polytetramethylene ether glycol and THF-neopentyl glycol copolymer are particularly preferable.

  In the polyalkylene glycol compound (C) of the present embodiment, the ratio of the mass of oxygen atoms to the total mass of the compound needs to be 1 to 36%, but is preferably 15% or more. % Is preferable. When the ratio of the mass of oxygen atoms to the total mass of the polyalkylene glycol compound is within the above range, the molded article produced from the resin composition tends to have higher gloss. From the same viewpoint, in the (C) polyalkylene glycol compound, the ratio of the mass of the oxygen atom to the mass of the entire compound is more preferably 18% or more, further preferably 20% or more, and It is more preferably at most 30%, further preferably at most 24%.

In addition, the ratio of the mass of the oxygen atom to the mass of the whole compound can be measured by the following method.
After pulverizing the resin composition, (C) extraction is performed in a solvent capable of dissolving the polyalkylene glycol compound (depending on the type of the polyalkylene glycol compound), and then the extract is concentrated and the solvent is removed to remove the sample. Is obtained, the structure of the polyalkylene glycol is specified using NMR for the obtained sample, the molecular weight is specified using GPC, and the mass ratio of oxygen atoms is calculated.

  By including the (C) polyalkylene glycol compound in which the mass ratio of oxygen atoms to the mass of the entire compound is within the above range, the resin composition of the present embodiment has a high glossiness and excellent metal appearance. A resin composition and a molded article having the same can be obtained, and at the same time, the operation stability during molding and extrusion can be improved. Further, the effect of suppressing the generation of formaldehyde from the resin composition and the molded article can be improved.

The number average molecular weight of the (C) polyalkylene glycol compound is preferably from 500 to 10,000, more preferably from 1,000 to 7,500, further preferably from 1,400 to 5,000, particularly preferably from 2,000 to 4,000. When the number average molecular weight satisfies the above range, the tendency of improving the glossiness 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.

  (C) The polyalkylene glycol compound preferably has a repeating structural unit derived from oxyalkylene having 4 or more carbon atoms in its molecular structure. When the repeating structural unit of oxyalkylene is an oxyalkylene having 4 or more carbon atoms, the above-mentioned (C) polyalkylene glycol compound may be directly exposed to water or placed in a high-humidity environment. Elution and the like are suppressed, and the tendency of the surface gloss to decrease can be reduced.

((D) metal pigment)
(D) The metal pigment contains the above (B) metal particles and (C) a polyalkylene glycol compound.
In the second aspect of the present embodiment, the proportion of the (B) metal particles contained in the (D) metal pigment is preferably from 70 to 95% by mass. When the above ratio is 70% by mass or more, the amount of the metal pigment can be suppressed, and the operation stability during extrusion and injection molding can be further improved. The dispersibility of the metal pigment can be improved at the time of blending, and the scattering of the metal powder can be suppressed. From the same viewpoint, the ratio is more preferably 80% by mass or more, and further preferably 92% by mass or less.

The proportion of the (C) polyalkylene glycol compound contained in the (D) metal pigment is preferably from 5 to 30% by mass. When the ratio is 5% by mass or more, the dispersibility of the metal pigment can be improved at the time of mixing the raw materials, and scattering of the metal powder can be suppressed. When the ratio is 30% by mass or less, the amount of the metal pigment can be reduced. And the operational stability during extrusion and injection molding can be further improved. From the same viewpoint, the ratio is more preferably equal to or greater than 8% by mass, and more preferably equal to or less than 20% by mass.
In the second aspect of the present embodiment, the (C) polyalkylene glycol compound is used as a pigment binder in the (D) metal pigment.

  In the present embodiment, the content of the metal pigment (D) in the resin composition of the second aspect is 0.1 to 15 parts by mass with respect to 100 parts by mass of the polyacetal resin. (D) By adjusting the content of the metal pigment in the above range, in the molded article of the resin composition of the present embodiment, the rigidity and impact resistance, which are the inherent mechanical properties of the polyacetal resin, are more favorably maintained. In addition, it is possible to suppress the generation of formaldehyde and to exhibit good metallic luster. Further, stable operation of the extruder at the time of extrusion processing and the molding machine at the time of injection molding becomes possible. 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, and preferably 1.5 parts by mass or more based on 100 parts by mass of the polyacetal resin. And more preferably 2.0 parts by mass or more, and preferably 12 parts by mass or less, more preferably 10 parts by mass or less, and 9.0 parts by mass or less. More preferably, it is particularly preferably 8.0 parts by mass or less.

  By using a metal pigment containing the (C) polyalkylene glycol compound as the metal pigment (D), stable operation of the extruder at the time of extrusion processing and the molding machine at the time of injection molding becomes possible, and this embodiment In the molded article of the resin composition in the form, it is possible to suppress the generation of formaldehyde, and it is possible to greatly improve the surface glossiness.

(D) The metal pigment is processed, for example, in a specific solvent (for example, mineral spirit or the like), and the metal particles (B) having a predetermined shape and (C) the polyalkylene glycol compound are arbitrarily mixed with stirring. After heating, the solvent can be prepared by evaporating and removing the solvent under reduced pressure.
Therefore, the (D) metal pigment may contain other components other than the (B) metal particles and the (C) polyalkylene glycol compound, such as the solvent used in the preparation. However, from the viewpoint of more reliably obtaining the intended effect, the proportion of the other components contained in the metal pigment (D) is preferably 5% by mass or less, more preferably 1% by mass or less. .

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

((E) lubricant)
The resin composition of the present embodiment may further contain one or more (E) lubricants. The lubricant generally reduces the viscosity of the resin melt and contributes to the improvement of the releasability from the metal surface during molding. In the present embodiment, the lubricant (E) is added by adding the lubricant. Higher gloss and FI values in addition to these.
(E) The lubricant can be used alone or in combination of two or more.

  Examples of the lubricant (E) include, but are not limited to, hydrocarbons, higher fatty acids, higher alcohols, aliphatic amides, and metal soaps. Among them, (A) reaction with a polyacetal resin Liquid paraffin, which is a hydrocarbon-based lubricant, is preferable from the viewpoint that the property is low and the influence on the physical properties is small.

  (E) The amount of the lubricant is not particularly limited as long as it does not hinder extrusion and injection molding, but is 0.01 to 0.5 part by mass with respect to 100 parts by mass of the polyacetal resin (A). Is preferably 0.05 to 0.45 parts by mass, particularly preferably 0.1 to 0.4 parts by mass. The addition amount in the above range is preferable because a molded article having a high glossiness can be obtained, and the operation state of the extruder at the time of extrusion and the resin measurement at the time of injection molding become stable.

((F) formaldehyde inhibitor)
It is preferable that the resin composition of the present embodiment contains the following formaldehyde inhibitor as needed, as long as the object of the present invention is not impaired. Examples of the formaldehyde inhibitor include an aminotriazine compound, a guanamine compound, a urea compound, and a carboxylic acid hydrazide compound. One of these formaldehyde inhibitors may be used alone, or two or more thereof may be used in combination.

  Examples of the aminotriazine compounds include melamine; melamine condensates such as melam, melem, and melon; melamine resins such as melamine formaldehyde resin; N, N ′, N ″ -mono, bis, tris, tetrakis, pentakis, Or N-hydroxyarylalkylmelamine compounds such as hexakis (o-, m- or p-hydroxyphenylmethyl) melamine; and the like.

  Examples of the guanamine-based compound include aliphatic guanamine-based compounds such as valerologanamine, caploganamine, heptanoguanamine, capryloganamine, and stealoganamine; succinoguanamine, glutaloganamin, adipoguanamine, and pimelogamine. Alkylenebisguanamines such as, sbeloganamine, azeroguanamine and sebacoguanamine; alicyclic guanamine compounds such as cyclohexanecarboguanamine, norbornenecarboguanamine, cyclohexenecarboguanamine, norbornanecarboguanamine and functional group-substituted derivatives thereof; benzoguanamine; aromatic guanamine-based compounds such as α- or β-naphthoguanamine and their functional group-substituted derivatives; phthaloganamin, isophthaloganamin, terephthaloganamin Polyguanamines such as butane, naphthalenediguanamine, biphenylenediguanamine and the like; aralkyl or aralkylenguanamines such as phenylacetoguanamine, β-phenylpropioguanamine, o-, m- or p-xylylenebisguanamine; acetal group-containing Heteroatom-containing guanamine-based compounds such as guanamines, dioxane ring-containing guanamines, tetraoxospiro ring-containing guanamines, and isocyanuric ring-containing guanamines;

  Examples of the functional group-substituted derivative in the alicyclic guanamine compound include an alkyl group, a hydroxy group, an amino group, an acetamino group, a nitrile group, a carboxy group, an alkoxycarbonyl group, a carbamoyl group, an alkoxy group, a phenyl group, and a cumyl group. And derivatives in which 1 to 3 cycloalkane residues are substituted with a functional group such as a hydroxyphenyl group.

  Examples of the functional group-substituted derivative in the aromatic guanamine-based compound include, for example, an alkyl group, a hydroxy group, an amino group, an acetamino group, a nitrile group, a carboxy group, an alkoxycarbonyl group, a carbamoyl group, an alkoxy group, a phenyl group, and cumyl. Group, a derivative in which a functional group such as a hydroxyphenyl group is substituted with 1 to 5 phenyl residues of benzoguanamine or naphthyl residues of naphthoguanamine, and examples of such aromatic guanamine-based compounds include o-, m- or p-toluguanamine, 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-dimethyl-4-hydroxy-benzoguanamine, 3,5-di -t- butyl-4-hydroxy benzoguanamine and the like.

Examples of the acetal group-containing guanamines include 2,4-diamino-6- (3,3-dimethoxypropyl-s-triazine and the like.
Examples of the dioxane ring-containing guanamines include, 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 above tetraoxospiro ring-containing guanamines include CTU-guanamine, CMTU-guanamine and the like.

  Examples of the isocyanuric ring-containing guanamines include 1,3,5-tris [2- (4 ′, 6′-diamino-s-triazin-2′-yl) ethyl] isocyanurate and 1,3,5- Tris [3- (4 ′, 6′-diamino-s-triazin-2′-yl) propyl] isocyanurate and the like.

  Examples of the urea compound include a chain urea compound and a cyclic urea compound.

  Examples of the chain urea-based compound include condensates of urea such as biurea, biuret, and form nitrogen with formaldehyde, and polyalkylene or arylene urea such as polynonamethylene urea.

  Examples of the cyclic urea-based compound include, for example, hydantoins, clotilidene diurea, acetylene urea, mono, di, tri or tetramethoxymethyl glycoluril such as mono, di, tri or tetraalkoxymethyl glycoluril, cyanuric acid, isocyanuric acid , Uric acid, and urazole. Examples of the hydantoins include, for example, hydantoin, 5-methylhydantoin, 5-ethylhydantoin, 5-isopropylhydantoin, 5-phenylhydantoin, 5-benzylhydantoin, 5,5-dimethylhydantoin, 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, Metal salts such as Al methyl salts of allantoin such as 5-methyl allantoin and allantoin dihydroxy aluminum salt.

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

  Examples of the aliphatic carboxylic acid hydrazide compound include monocarboxylic acid hydrazides such as lauric hydrazide, stearic hydrazide, 12-hydroxystearic hydrazide, and 1,2,3,4-butanetetracarboxylic acid hydrazide; Acid mono- or dihydrazide, glutaric mono- or dihydrazide, adipic mono- or dihydrazide, pimelic mono- or dihydrazide, suberic acid mono- or dihydrazide, azelaic mono- or dihydrazide, sebacic mono- or dihydrazide, dodecane di-acid mono- or dihydrazide, hexadecane di Polycarboxylic acid hydrazides such as acid mono- or dihydrazide, eicosane diacid mono- or dihydrazide, and 7,11-octadecadien-1,18-dicarbohydrazide.

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

  Examples of the aromatic carboxylic acid hydrazide compound include monocarboxylic acid hydrazides such as benzoic acid hydrazide and its functional group-substituted derivatives, α- or β-naphthoic acid hydrazide and their functional group-substituted derivatives; 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 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 Mono- or dihydrazide of ketone dicarboxylic acid, mono- or dihydrazide of 4,4 ″ -terphenyl dicarboxylic acid, mono- or dihydrazide of 4,4 ′ ″-quarterphenyl dicarboxylic acid, mono-, di-, 1,2- or 4-benzenetricarboxylic acid, di or And polycarboxylic acid hydrazides such as 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 derivative include, 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-di-t-butylbenzoic acid hydrazide and the like , Alkyl group, hydroxy group, acetoxy group, amino group, acetamino group, nitrile group, carboxy group, alkoxycarbonyl Group, a carbamoyl group, an alkoxy group, a phenyl group, a benzyl group, cumyl group, derivative functional group is substituted 1-5 phenyl residues benzoguanamine such as hydroxyphenyl group and the like. Examples of the above-mentioned α- or β-naphthoic acid hydrazide and their functional group-substituted derivatives include 3-hydroxy-2-naphthoic acid hydrazide, 6-hydroxy-2-naphthoic acid hydrazide and the like.

  The above-mentioned formaldehyde inhibitor is supported on a layered substance and a porous substance (hydrotalcite, montmorillonite, silica gel, alumina, titania, zirconia, sepiolite, smectite, palygorskite, imogolite, zeolite, activated carbon, etc.). Use is also possible.

  Among the above-mentioned formaldehyde inhibitors, an aliphatic carboxylic acid hydrazide compound and an aromatic carboxylic acid hydrazide compound are preferable, and an aliphatic carboxylic acid hydrazide compound is more preferably used.

  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 5 parts by mass, based on 100 parts by mass of the polyacetal resin (A). To 2 parts by mass, more preferably 0.02 to 1 part by mass. When the amount of the formaldehyde inhibitor is within the above range, a sufficient formaldehyde inhibitory effect can be obtained and mold deposits can be suppressed, which is preferable.

(Other components)
The resin composition of the present embodiment may contain a commonly used additive (G). The (G) additive is not particularly limited, but a stabilizer or the like used in the conventional (A) polyacetal resin is preferable.
Examples of the stabilizer include an antioxidant and a weather stabilizer. Furthermore, formic acid or formaldehyde scavengers can be used. The above additives may be used alone or in combination of two or more. Further, in order to enhance the design, various colorants can be contained as complementary color pigments as necessary. Examples of the colorant include organic pigments and inorganic pigments, but are not particularly limited, and may be a combination of one or more colorants.

-Antioxidant-
As the antioxidant, a hindered phenol-based antioxidant is preferable. 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 Over g), and the like.

  Other hindered phenolic antioxidants include, for example, tetrakis- (methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate methane, 3,9 -Bis (2- (3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy) -1,1-dimethylethyl) 2,4,8,10-tetraoxaspiro (5,5 ) Undecane, N, N'-bis-3- (3'5'-di-tert-butyl-4-hydroxyphenol) propionylhexamethylenediamine, N, N'-tetramethylenebis-3- (3'-methyl -5'-tert-butyl-4-hydroxyphenol) propionyldiamine, N, N'-bis- (3- (3,5-di-tert-butyl-4-hydroxyphenol) propionyl) hydrazi , 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, etc. Among the above-mentioned hindered phenolic antioxidants, triethylene glycol-bis- (3- (3-t-butyl-5-methyl-) is exemplified. 4-Hydroxyphenyl) -propionate) and tetrakis- (methylene-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate methane are preferred.

  The amount of the hindered phenolic antioxidant to be added is preferably 0.01 to 2 parts by mass, more preferably 0.02 to 1 part by mass, per 100 parts by mass of the polyacetal resin (A). When the addition amount is 0.01 to 2 parts by mass, the thermal stability at the time of molding the resin composition of the present embodiment is improved, and the resin composition becomes favorable.

−Weather stabilizer−
Examples of the weather resistant stabilizer include a hindered amine-based stabilizer and an ultraviolet absorber.
Examples of hindered amine stabilizers include piperidine derivatives having a sterically hindered group, such as ester group-containing piperidine derivatives, ether group-containing piperidine derivatives, amide group-containing piperidine derivatives, and high-molecular-weight piperidine derivative polycondensates. No.

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-phenylcarbamooxy-2,2,6,6-tetramethylpiperidine, bis (2 2,6,6-tetramethyl-4-piperidyl) oxalate, 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] butylmalonate, bis (2,2,6,6-te Lamethyl-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 2,6,6-pentamethyl-4-piperidyl) sebacate, bis (1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl separate, bis (2,2,6,6 -Tetramethyl-1- (octyloxy) -4-piperidinyl) ester, bis (2,2,6,6-tetramethyl-4-piperidyl) terephthalate, tris (2,2,6,6- Tramethyl-4-piperidyl) benzene-1,3,5-tricarboxylate, tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate and the like No.
Examples of the ether group-containing piperidine derivatives include 4-methoxy-2,2,6,6-tetramethylpiperidine, 4-cyclohexyloxy-2,2,6,6-tetramethylpiperidine, and 4-phenoxy-2,2 , 6,6-tetramethylpiperidine, 4-benzyloxy-2,2,6,6-tetramethylpiperidine, 1,2-bis (2,2,6,6-tetramethyl-4-piperidyloxy) ethane and the like Is mentioned.

Examples of the amide group-containing piperidine derivative include 4- (phenylcarbamoyloxy) -2,2,6,6-tetramethylpiperidine and bis (2,2,6,6-tetramethyl-4-piperidyl) hexamethylene- 1,6-dicarbamate 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, 1,2,3 Of 1,2,2,6,6-pentamethyl-4-piperidinol with 1,4-butanetetracarboxylic acid and tridecyl alcohol; 1,2,3,4-butanetetracarboxylic acid with 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.

One of the above various hindered amine-based stabilizers may be used alone, or two or more may be used in combination.
Among them, preferred hindered amine-based stabilizers include bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and 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 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 from 0.01 to 5 parts by mass, more preferably from 0.1 to 2 parts by mass, and still more preferably from 0.1 to 5 parts by mass, per 100 parts by mass of the polyacetal resin (A). １．５1.5 parts by mass.

  It is preferable that the resin composition of the present embodiment further contains an ultraviolet absorber as the weather-resistant stabilizer. Thereby, in the molded article obtained from the resin composition of the present embodiment, an effect of improving weather resistance (light stability) can be obtained. Examples of the ultraviolet absorber include a benzotriazole-based compound, a benzophenone-based compound, an oxalic anilide-based compound, and a hydroxyphenyl-1,3,5-triazine-based compound.

Examples of the benzotriazole-based compound include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole and 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) benzotriazole Hydroxyl groups such as, 2- (2'-hydroxy-3 ', 5'-di-t-amylphenyl) benzotriazole and 2- (2'-hydroxy-3', 5'-diisoamylphenyl) benzotriazole Benzotriazoles having an alkyl group (preferably a C1-6 alkyl group) and a substituted aryl group; 2- [2'-hydroxy-3 ', 5'-bis (α, α-dimethylbenzyl) phenyl] benzotriazole and the like Having a hydroxyl group and an aralkyl group or an aryl-substituted aryl group; 2- (2′-hydroxy-4′-octoxy) And the like; Eniru) is a hydroxyl group and an alkoxy group (preferably a benzotriazole like benzotriazole and a C _1-12 alkoxy group) a substituted aryl group. Preferred benzotriazole-based compounds are benzotriazoles having a hydroxyl group and a C _3-6 alkyl-substituted C _6-10 aryl group (particularly a phenyl group), and a hydroxyl group and a C _6-10 aryl-C _1-6 Benzotriazoles having an alkyl group (particularly a phenyl C _1-4 alkyl group) and a substituted aryl group.

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

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

Examples of benzophenones having a hydroxyl group and an alkoxy group include, for example, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, and 2,2 ′ -Dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone and the like. Preferred benzophenone-based compounds are benzophenones having a hydroxyl group and a hydroxyl group-substituted C _6-10 aryl group or a C _6-10 aryl-C _1-4 alkyl group, particularly, a hydroxyl group and a hydroxyl group-substituted phenyl C _1. Benzophenones having a _-2 alkyl group are more preferred.

Examples of the oxalic acid anilide-based compound include N- (2-ethylphenyl) -N ′-(2-ethoxy-5-t-butylphenyl) oxalic acid diamide and N- (2-ethylphenyl) -N ′ -(2-ethoxy-phenyl) oxalic acid diamide and the like.
Examples of the hydroxyphenyl-1,3,5-triazine-based compound include 2,4-diphenyl-6- (2-hydroxyphenyl) -1,3,5-triazine and 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-dodecyl (Oxyphenyl) -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 (α, α-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 even more preferably 0.1 to 2 parts by mass, per 100 parts by mass of the polyacetal resin (A). 1 to 1.5 parts by mass.

  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 and the ultraviolet absorber is such that the ultraviolet absorber / hindered amine stabilizer (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.

-Formic acid or formaldehyde scavenger-
It is preferable that the resin composition of the present embodiment further uses the formic acid or formaldehyde scavenger. Examples of the formaldehyde or formic acid scavenger include, for example, compounds and polymers containing formaldehyde-reactive nitrogen, fatty acid calcium salts, hydroxides of alkali metals or alkaline earth metals, inorganic acid salts, carboxylate salts or alkoxides. No.

  Examples of the compound containing formaldehyde-reactive nitrogen include dicyandiamide, amino-substituted triazine, and co-condensates of amino-substituted triazine and formaldehyde.

  Examples of the amino-substituted triazine include melamine, guanamine (2,4-diamino-sym-triazine), melamine (2,4,6-triamino-sym-triazine), N-butylmelamine, N-phenylmelamine, N, N-diphenylmelamine, N, N-diallylmelamine, N, N ′, N ″ -triphenylmelamine, N-methylolmelamine, N, N′-dimethylolmelamine, N, N ′, N ″ -trimethylol Melamine, benzoguanamine (2,4-diamino-6-phenyl-sym-triazine) and the like. Also, 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 and the like. .

Examples of the co-condensate of the amino-substituted triazine and formaldehyde include a melamine-formaldehyde polycondensate.
Among them, dicyandiamide, melamine and melamine-formaldehyde polycondensate are preferred.

Examples of the polymer having formaldehyde reactive nitrogen include, for example, a polymer obtained by polymerizing a polyamide resin, acrylamide and a derivative thereof, or acrylamide and a derivative thereof and another vinyl monomer in the presence of a metal alcoholate, Polymers obtained by polymerizing acrylamide and its derivatives or acrylamide and its derivatives and other vinyl monomers in the presence of radical polymerization, amines, amides, urea, urethane, and other polymers having a nitrogen atom, and the like. .
Examples of the polyamide resin include nylon 4-6, nylon 6, nylon 6-6, 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 its derivative, or acrylamide and its derivative and another vinyl monomer in the presence of a metal alcoholate include a poly-β-alanine copolymer. These polymers and copolymers are described in JP-B-6-12259 (U.S. 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.

  The fatty acid calcium salt includes, for example, a calcium salt of a saturated or unsaturated fatty acid having 10 to 36 carbon atoms, and may be substituted with a hydroxyl group. Examples of the saturated fatty acids include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, melicic acid, and celloplastic acid. Examples of the unsaturated fatty acids include undecylenic acid, oleic acid, elaidic acid, setreic acid, erucic acid, brassic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, prepiolic acid, and stearic acid. Among these fatty acids, particularly preferred are palmitic acid, stearic acid and 12-hydroxystearic acid.

  Examples of the hydroxide, inorganic acid salt, carboxylate or alkoxide of the alkali metal or alkaline earth metal include, for example, hydroxides of sodium, potassium, magnesium, calcium or barium, carbonates of the above metals, phosphoric acid Salts, silicates, borates, carboxylate salts are included. In addition, as the carboxylate, the above-mentioned fatty acid calcium salt is excluded. Examples of the carboxylic acid corresponding to the above carboxylate include a saturated or unsaturated aliphatic carboxylic acid having 10 to 36 carbon atoms, and these carboxylic acids may be substituted with a hydroxyl group. Examples of the saturated aliphatic carboxylic acid include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, serotinic acid, montanic acid, melissic acid, and celloplastic acid. Examples of the unsaturated aliphatic carboxylic acid include undecylenic acid, oleic acid, elaidic acid, setleic acid, erucic acid, brassic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid, propiolic acid, and stearolic acid. Can be Examples of the alkoxide include methoxide and ethoxide of the above-mentioned metals.

  Compounds and polymers containing formaldehyde-reactive nitrogen, which are scavengers of the formic acid or formaldehyde, and the respective addition amounts of polymers, fatty acid calcium salts, hydroxides of alkali metals or alkaline earth metals, inorganic acid salts, carboxylate salts or alkoxides 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 addition amount is 0.01 to 1 part by mass, the thermal stability during molding of the resin composition of the present embodiment is improved, the amount of formaldehyde generated from the molded body is reduced, and the heat aging resistance is more improved. It will be good.

  Examples of the organic pigment include phthalocyanine pigments, condensed azo pigments, azo lake pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments, and condensed polycyclic pigments.

  Examples of the inorganic pigment include, for example, zinc oxide, titanium dioxide, red iron oxide, chromium oxide, simple oxides such as iron black, sulfides such as cadmium yellow, cadmium orange, and cadmium red, graphite, zinc yellow, and chromium vermilion. And ferrocyanides such as navy blue, silicates such as ultramarine blue, and carbon black.

  The amount of the colorant to be added is preferably 0.0001 to 2 parts by mass, more preferably 0.0005 to 1 part by mass, based on 100 parts by mass of the polyacetal resin (A). By setting the amount of the coloring agent in the above range, the effect of improving the design properties can be obtained without reducing the mechanical strength of the molded article and particularly promoting the generation of formaldehyde in the polyacetal resin (A).

  Furthermore, the resin composition of the present embodiment may be, if desired, various inorganic fillers, other thermoplastic resins, softeners, softening agents, crystal nucleating agents, mold release agents, and the like conventionally used as long as the object of the present invention is not impaired. May be contained.

(Production method)
The resin composition of the present embodiment is obtained, for example, by using a generally used melt kneader and melting and mixing some of the above-mentioned raw materials. Examples of the melt kneader include a kneader, a roll mill, a single-screw extruder, a twin-screw extruder, and a multi-screw extruder.

  The melt-kneading temperature may be selected according to the melting point or softening point of the polyacetal resin (A) used. The temperature of the melt kneading is preferably 1 to 100 ° C higher than the melting point or softening point of the polyacetal resin (A), more preferably 10 to 60 ° C higher, more preferably 20 to 50 ° C higher. The melting point or softening point can be determined by differential scanning calorimetry (DSC) according to JIS K7121. Further, in order to maintain the quality and the working environment, it is preferable to replace the inside of the system with an inert gas or to perform degassing with single-stage and multi-stage vents.

  In the first aspect of the present embodiment, when (A) the polyacetal resin is in the form of pellets, (B) in order to maintain a uniform dispersion state of each component including the metal particles in the (A) polyacetal resin, If necessary, a stabilizer (an antioxidant, a formaldehyde or formic acid scavenger and a weathering stabilizer, a formaldehyde scavenger, etc.) is added in advance using an impregnating agent and mixed, and then (B) the metal particles and (B) It is preferable to melt-knead after mixing the (C) polyalkylene glycol compound and, if necessary, the (E) lubricant.

  When the (A) polyacetal resin is in the form of pellets, a part or all of the pellets are pulverized into a powder form, and the powder is stabilized using the powdery (A) polyacetal resin and, if necessary, an impregnating agent. Agents (antioxidant, formaldehyde or formic acid scavenger and weather stabilizer, formaldehyde scavenger, etc.), then (B) metal particles and (C) polyalkylene glycol compound, and if necessary, (E) lubricant It is also preferable to melt-knead after mixing.

  In the second aspect of the present embodiment, when the (A) polyacetal resin is in the form of pellets, (D) in order to maintain a uniform dispersion state of each component including the metal pigment in the (A) polyacetal resin. If necessary, additives (antioxidant, formaldehyde or formic acid scavenger and weather stabilizer, formaldehyde scavenger, etc.) are added in advance using an impregnating agent, and the mixture is mixed. It is preferable to melt-knead after mixing and, if necessary, mixing the lubricant (E).

  When the (A) polyacetal resin is in the form of pellets, a part or all of the pellets are pulverized into a powder form, and the powder is stabilized using the powdery (A) polyacetal resin and, if necessary, an impregnating agent. Mixing (antioxidant, formaldehyde or formic acid scavenger and weather stabilizer, formaldehyde scavenger, etc.), then (D) metal pigment, and if necessary (E) lubricant, then melt Kneading is also preferred.

  In the present embodiment, examples of the additive include aliphatic hydrocarbons, aromatic hydrocarbons and modified products thereof, mixtures thereof (liquid paraffin, mineral oil, and the like), and fatty acid esters of polyols. In order to prevent damage in the step of blending the metal particles (B) or the metal pigment (D), blending in a subsequent step is preferable.

  When the resin composition contains the (D) metal pigment as in the resin composition of the second embodiment, a part of the (C) polyalkylene glycol compound in the (D) metal pigment is replaced with (D) ) It may be separated from the metal particles (B) in the metal pigment and dispersed in the resin composition (for example, it may be separated and dispersed during melt-kneading of each component).

  Further, when the resin composition of the present embodiment is produced, (A) the polyacetal resin and a stabilizer (at least one selected from an antioxidant, a formaldehyde or formic acid scavenger, and a weather resistance stabilizer) are previously melt-kneaded. It is also possible to keep. For this preliminary kneading, a commonly used melt kneader can be used. The melting and kneading temperature is selected according to the melting point or softening point of the crystalline resin (A) used. A temperature higher by 1 to 100 ° C than the melting point or softening point is preferable, a temperature higher by 10 to 60 ° C is more preferable, and a temperature higher by 20 to 50 ° C is further preferable. Examples of the melt kneader include a kneader, a roll mill, a single-screw extruder, a twin-screw extruder, and a multi-screw extruder. In order to maintain the quality and the working environment, it is preferable to replace the inside of the system with an inert gas or to perform degassing with single-stage and multi-stage vents.

(Molded body)
A molded article can be produced by molding the resin composition of the present embodiment.
Examples of the method for producing the molded body include known molding methods such as extrusion molding, injection molding, vacuum molding, blow molding, injection compression molding, decorative molding, gas assist injection molding, foam injection molding, low pressure molding, and ultra-thin molding. Methods include meat injection molding (ultra high-speed injection molding) and in-mold composite molding (insert molding, outsert molding). In particular, from the viewpoints of quality, production stability, economy, and the like, injection molding, injection compression molding, and a molding method combining these and composite molding in a mold are preferable.

  Further, the method of bonding the resin composition of the present embodiment to various resins including rubber and / or elastomer (such as ultrasonic bonding, high frequency bonding, hot plate bonding, hot press molding, multilayer injection molding, and multilayer blow molding is not limited. ) Can produce a molded article having two or more layers having desired characteristics and appearance. Thereby, excellent performance (impact resistance, slidability, chemical resistance, etc.) of each resin is imparted to each, and a molded article having an appearance having excellent design properties can be obtained.

(Characteristic)
The resin composition of the present embodiment has good retention stability at the time of molding and extrusion, has few appearance defects, furthermore, has little volatilization of the organic solvent from the resin composition, and has an excellent metallic appearance. A molded article having a high glossiness and a high FI value and having a metallic appearance excellent in aesthetic appearance can be obtained.

The formaldehyde generation amount of the resin composition of the present embodiment is preferably 5 mg / kg or less, more preferably 3 mg / kg or less.
In addition, the amount of formaldehyde generated can be measured by the method described in Examples described later.

The resin composition of the present embodiment preferably has an FI value of 13 or more, more preferably 14 or more. The FI value can be measured by a method described in Examples described later.
Here, a phenomenon in which the brightness changes with a change in the viewing angle is called a flip-flop (F / F) phenomenon, and a quantitative value representing this phenomenon is called an FI (flop index) value. FI values are determined from the values of lightness (L * ₁₅ °, L * ₄₅ ° and L * ₁₁₀ °) at 15, 45 and 110 degrees using the formula originally proposed by DuPont. (ABJ Rodriguez, JOCCA, (1992 (4)), pp. 150-153). Specifically, the FI value is obtained by the following formula, and the FI value is high, that is, the brightness (L ^* ) in the highlight direction (specular reflection direction with respect to the incident angle of light) and the shade direction (non-specular reflection direction) ^. In general, the larger the difference is, the higher the metallic feeling is felt.

The glossiness of the resin composition of the present embodiment immediately after injection molding is preferably 60 or more, more preferably 70 or more. Further, it is preferable that the degree of glossiness after standing for 48 hours in an environment of a temperature of 80 ° C. and a humidity of 90% is small from the glossiness immediately after injection molding.
In addition, the glossiness can be measured by a method described in Examples described later.
Here, the glossiness is one of the indicators of the metallic appearance. Further, the glossiness depends on the smoothness of the surface of the molded article, and a metallic material which is formed by kneading a glittering material such as a metal pigment and the like generally shows a tendency that the glossiness decreases. When the glossiness is low, the lightness, FI value, and the like are reduced due to the effect of scattering of the reflected light on the surface of the molded product, so that the quality of the metallic appearance tends to decrease.
As a conventional method of improving the glossiness, there are many cases where the hardware side corresponds to such a method as increasing the temperature of a mold or a heat and cool method which has been increasingly used in recent years. Therefore, in the present invention, in view of the above-mentioned problems of the prior art, by adding a specific (C) polyalkylene glycol, the retention stability at the time of molding and extrusion is good, and a molded article is obtained. It has been found that a resin composition having a metal-like appearance and a molded article having a low appearance defect, a low volatilization of an organic solvent from the resin composition, and an excellent metal appearance can be obtained.

(Application)
The molded article of the resin composition of the present embodiment can be used particularly for interior / exterior parts having a mechanical portion or a sliding portion. For example, used as any part 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 housing equipment, and automotive interior / exterior parts Can be In particular, it is used as any part selected from the group consisting of a handle, a switch, and a button that requires an excellent appearance. Furthermore, in order to use a molded article obtained from the resin composition of the present embodiment as an external part, use of an embossing die at the time of molding or imparting a design surface by embossing the molded article improves the appearance. It is preferable because the effect is exhibited.

  And according to the resin composition of the present embodiment, it is a molded article having a metallic luster without applying a process such as plating or painting to the surface, and is excellent in thermal stability and weather resistance, and has excellent mechanical properties. (For example, tensile properties, impact strength) are maintained, and a molded article having high glossiness and FI value and excellent appearance properties can be obtained. Furthermore, since the molded article obtained from the resin composition according to the present embodiment has good appearance characteristics as described above, it can have a practically good appearance without coating. Therefore, an appearance excellent in design can be efficiently obtained without using a solvent. Further, the resin composition of the present embodiment is excellent in production stability, can be manufactured in a favorable working environment, and is excellent in cost and environment.

  Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to Examples described later.

(1) Main raw materials <(A) polyacetal resin>
The (A) polyacetal resin used is as follows.
(A-1) "Tenac C 4513" manufactured by Asahi Kasei Corporation, polyacetal copolymer (melting point: 165 ° C)

<(B) Metal particles>
A ball mill having an inner diameter of 30 cm and a length of 35 cm is charged with a compound consisting of 250 g of atomized aluminum powder (volume average particle diameter of 3.2 μm), 1.2 kg of mineral spirit, and 25 g of stearic acid, and glass beads having a diameter of 3 mm. Using 15 kg of specific gravity (2.6), the mixture was milled at 60 rpm for 10 hours.
After the end of the grinding, the slurry in the mill was washed out with mineral spirit, passed through a 400-mesh vibrating sieve, and the passed slurry was filtered with a filter, followed by volatilization removal under reduced pressure to obtain a concentrated slurry (b1-1). Metal particles (aluminum particles) were obtained (solid content: equivalent to 90% by mass).
In addition, except that the operation was performed by changing the particle size and the pulverization time of the atomized aluminum powder, the volume average particle diameter and the mean Metal particles (aluminum particles) of (b1-2) to (b1-5) having different particle thicknesses were obtained (solid content: equivalent to 90% by mass).

The particle size distribution of each of the obtained aluminum particles was measured by a laser diffraction particle size distribution analyzer (manufactured by Shimadzu Corporation, trade name “SALD-2300”), and the 50% value of the obtained particle size distribution was used to determine the aluminum particle size. volume to obtain an average particle diameter (D _50). Mineral spirit was used as a measurement solvent, and aluminum particles serving as a sample were subjected to ultrasonic dispersion for 3 minutes as pretreatment.
In addition, after adding 1 to 2 ml of a mineral spirit solution of 5% stearic acid to 1 g of each of the obtained aluminum particles and pre-dispersing the mixture, 50 ml of petroleum benzene was added and mixed, followed by heating at 40 to 45 ° C for 2 hours. The water-diffused area (WCA) of the powder that was suction-filtered through the filter and powdered was measured. From the WCA measurement, the following formula:
t (μm) = 0.4 / WCA (m ² / g)
The average particle thickness (t) was calculated according to The results were as follows.
(B1-1): D ₅₀ = 10 μm, t = 0.22 μm
(B1-2): D ₅₀ = 6 μm, t = 0.15 μm
(B1-3): D ₅₀ = 25 μm, t = 0.38 μm
(B1-4): D ₅₀ = 10 μm, t = 0.60 μm
(B1-5): D ₅₀ = 45 μm, t = 0.39 μm

<(C) polyalkylene glycol compound>
The polyalkylene glycol compound (C) used in the examples and comparative examples is as follows.
(C-1) Polytetramethylene ether glycol (number average molecular weight: 650, mass ratio of oxygen atoms: 24.0%)
(C-2) Polytetramethylene ether glycol (number average molecular weight: 1000, mass ratio of oxygen atoms: 23.4%)
(C-3) Polytetramethylene ether glycol (number average molecular weight 1400, mass ratio of oxygen atoms: 23.1%)
(C-4) Polytetramethylene ether glycol (number-average molecular weight: 2000, mass ratio of oxygen atoms: 22.8%)
(C-5) Polytetramethylene ether glycol (number-average molecular weight 3000, mass ratio of oxygen atoms: 22.6%)
(C-6) THF-neopentyl glycol copolymer (number average molecular weight 1800, mass ratio of oxygen atoms: 21.0%)
(C-7) Polyethylene glycol (number-average molecular weight: 400, mass ratio of oxygen atoms: 38.7%)
(C-8) Polyethylene glycol (number-average molecular weight: 1,000, mass ratio of oxygen atoms: 37.3%)
(C-9) Polyethylene glycol (number-average molecular weight: 2000, mass ratio of oxygen atoms: 36.8%)
(C-10) Polyethylene glycol (number-average molecular weight: 6000, mass ratio of oxygen atoms: 36.5%)
(C-11) Polypropylene glycol (diol type, number average molecular weight 400, mass ratio of oxygen atom: 30.2%)
(C-12) Polypropylene glycol (diol type, number average molecular weight 1000, mass ratio of oxygen atom: 28.6%)
(C-13) Polypropylene glycol (diol type, number average molecular weight 2000, proportion of oxygen atom mass: 28.1%)
(C-14) Polypropylene glycol (triol type, number average molecular weight 3000, proportion of mass of oxygen atom: 28.4%)

<(D) Metal pigment>
In a container capable of stirring and depressurizing the contents in a heated state, 200 g of the above-mentioned concentrated slurry of metal particles (solid content: equivalent to 90% by mass) and polyalkylene glycol in a combination shown in Table 1 20 g of a pigment binder such as a compound was charged, and the internal temperature was raised to 70 ° C. while stirring. The pressure was reduced while the internal temperature was stable, and the mixture was concentrated to obtain metal pigments (d-1) to (d-25) (metal particles: equivalent to 90% by mass, pigment binder: equivalent to 10% by mass). In the production of the metal pigment (d-13), no pigment binder was used, and finally metal particles having 10% by mass of mineral spirit remaining were obtained as the metal pigment (d-13).
Similarly, in the combinations shown in Table 1, 178 g of the above-mentioned concentrated slurry of metal particles (solid content: equivalent to 90% by mass) and 40 g of a pigment binder were charged, and the internal temperature was raised to 70 ° C. while stirring. The pressure was reduced while the internal temperature was stabilized, and the mixture was concentrated to obtain a metal pigment (d-26) (metal particles: equivalent to 80% by mass, pigment binder: equivalent to 20% by mass).

<(E) Lubricant>
The (E) lubricant used was as follows.
(E-1) Liquid paraffin (trade name: Sumoil PS-260, manufactured by Matsumura Oil Research Institute)

<(F) Formaldehyde inhibitor>
The (F) formaldehyde inhibitors used are as follows.
(F-1) Sebasic acid dihydrazide manufactured by Nippon Finechem Co., Ltd. First class reagent)

(2) Evaluation method <FI value>
Pellets of the resin compositions prepared in Examples and Comparative Examples described below 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 prepared by injection molding for 20 seconds at a mold temperature of 77 ° C. This test piece was produced using a mold having a length of 90 mm, a width of 50 mm, and a thickness of 2.5 mm.
The appearance of the test piece was confirmed using BYK-mac manufactured by Big Gardner Co., Ltd.
A method for measuring the FI value will be described with reference to FIG. FIG. 1 is a diagram showing a method of evaluating an FI value. FI value is obtained by irradiating the surface of a molded article with light from a certain direction as shown in FIG. 1 and shifting the light receiving angle by 15 °, 45 °, 110 ° with respect to the specularly reflected light. ^* Measure the values (L * ₁₅ °, L * ₄₅ ° and L * ₁₁₀ °) (lightness). Next, FI values were determined by substituting the measured L ^* values into the above formula. Generally, the higher the FI value, the higher the metallic texture.

<Gloss>
The glossiness was measured using the test piece used in the measurement of the FI value, using a gloss meter (manufactured by HORIBA, Ltd., “IG-320”) and conforming to JIS Z8741 at an angle of 60 ° on the surface of the molded body. It was measured. In general, it is assumed that the higher the gloss, the smoother the surface of the molded product and the higher the degree of following the surface of the mold.
In addition, immediately after obtaining a test piece by injection molding, and in ESPEC CORP. After the test piece was allowed to stand for 48 hours in an environment of a temperature of 80 ° C. and a humidity of 90% in a high temperature and humidity machine “PL-2KT”, the glossiness of the molded article was measured, and the glossiness before and after the standing was measured. Changes were confirmed.

<Amount of formaldehyde generated (VDA275)>
Using an injection molding machine (trade name “IS-100GN” manufactured by Toshiba Machine Co., Ltd.), the pellets produced in Examples and Comparative Examples described below were used at a cylinder temperature of 220 ° C., an injection time of 15 seconds, a cooling time of 20 seconds, Injection molding was performed under the condition of a mold temperature of 77 ° C. to prepare a test piece (100 mm long × 40 mm wide × 3 mm thick sheet).
Next, the amount of formaldehyde released from the test piece was determined by the following method (VDA275 method). First, 50 mL of distilled water and the above test piece were put 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. The absorption peak of the reaction product at a wavelength of 412 nm was measured with a UV spectrometer, and the amount of formaldehyde released (mg / kg) was determined.

<Evaluation of extrusion stability>
The extruded raw material obtained by mixing the materials with the compounding recipes corresponding to the respective examples and comparative examples was discharged from the vent at a set temperature of 200 ° C., a rotation speed of 80 rpm, and a discharge rate of 10 kg / hour using a single screw extruder equipped with a 30 mm vent. Pellets were obtained by performing melt kneading (melt mixing) while degassing. Regarding the operation state of the extruder at the time of this melt kneading, if it is stable without venting and surging occurring during operation, it is `` ○ '', venting does not occur during operation, but sometimes surging etc. It was determined to be "△" when it occurred, and "x" when vent-up occurred frequently during operation.

(3) Preparation of pellets of resin composition [Example 1]
After blending (a-1) 100 parts by mass of the polyacetal copolymer, (c-1) 0.35 parts by mass of polytetramethylene ether glycol, and (f-1) 0.08 parts by mass of sebacic dihydrazide with a mixer, b-1) 3.5 parts by mass of aluminum pigment was added and blended.
The mixture was melt-kneaded (melt-mixed) using a single-screw extruder equipped with a 30 mm vent at a set temperature of 200 ° C., a rotation speed of 80 rpm, and a discharge rate of 10 kg / hour while being deaerated from the vent to obtain pellets. .
After drying the obtained pellets at 80 ° C. for 3 hours, each of the above evaluations was performed.
The evaluation results are shown in Table 2 below.

[Examples 2 to 29, Comparative Examples 1 to 5, 9 to 23]
Example 1 was repeated except that the components (A), (B), (C), and (F) had the compositions shown in Table 2.

[Example 30]
(A-1) 100 parts by mass of a polyacetal copolymer, (c-4) 0.35 parts by mass of polytetramethylene ether glycol, (e-1) 0.35 parts by mass of liquid paraffin, (f-1) sebacic acid dihydrazide 0 After blending 0.08 parts by mass with a mixer, (b-1) 3.5 parts by mass of an aluminum pigment was added and blended.
The mixture was melt-kneaded (melt-mixed) using a single-screw extruder equipped with a 30 mm vent at a set temperature of 200 ° C., a rotation speed of 80 rpm, and a discharge rate of 10 kg / hour while being deaerated from the vent to obtain pellets. .
After drying the obtained pellets at 80 ° C. for 3 hours, each of the above evaluations was performed.
The evaluation results are shown in Table 2 below.

[Examples 31 to 37, Comparative Examples 6 to 8, 24 to 27]
Example 30 was carried out in the same manner as in Example 30, except that the components (A) to (E) had the compositions shown in Table 2.

As shown in Table 2, in Examples 1 to 37 in which the predetermined (C) polyalkylene glycol was added, Comparative Examples 1 to 8 in which the (C) polyalkylene glycol was not added, and (C) the polyalkylene glycol as the whole molecule. Higher gloss is obtained as compared with Comparative Examples 9 to 19 and Comparative Examples 24 to 27 in which a polyethylene glycol compound in which the mass ratio of oxygen occupying is out of a predetermined range is added. Particularly, in Examples 30 to 37 in which liquid paraffin was further added as (D) a lubricant, higher glossiness and FI value were obtained as compared with the case where no lubricant was added.
In Comparative Examples 9 to 19 and Comparative Examples 24 to 27 using (C) polyethylene glycol in which the ratio of the mass of oxygen atoms to the mass of the entire compound is out of a predetermined range, as the polyalkylene glycol, Examples were used. The VDA 275 value was soaring as compared to.
In Comparative Examples 20 to 23, (C) the polyalkylene glycol in which the mass ratio of the oxygen atom to the mass of the entire compound is in the predetermined range is used, but (B) the shape of the metal particles is out of the predetermined range. The result showed that the FI value was lowered due to the deviation.

[Example 41]
After blending (A) 100 parts by mass of the component (a-1) as a polyacetal resin and 0.08 parts by mass of the component (f-1) as a (F) formaldehyde inhibitor, (D) a metal pigment (D-1) component 6.0 parts by mass was added to obtain a mixture. The obtained mixture was melt-kneaded (melt-mixed) using a single-screw extruder equipped with a 30 mm vent at a set temperature of 200 ° C., a rotation speed of 80 rpm, and a discharge rate of 10 kg / hour while being deaerated from the vent. Pellets of the resin composition were obtained. After the obtained pellets were dried at 80 ° C. for 3 hours, each of the above evaluations was performed. The evaluation results are shown in Table 3 below.

[Examples 42 to 63, Comparative Examples 41 to 54]
(A) Polyacetal resin, (D) metal pigment, and (F) formaldehyde inhibitor were carried out in the same manner as in Example 1 except that the compositions were as shown in Table 3. The evaluation results are shown in Table 3 below.

[Example 64]
(A) 100 parts by weight of the component (a-1) as a polyacetal resin, (E) 0.30 part by weight of the component (e-1) as a lubricant, and (F) (f-1) as a formaldehyde inhibitor After blending 0.08 parts by mass of the component with a mixer, 6.0 parts by mass of the component (d-3) as a metal pigment (D) was added to obtain a mixture. The obtained mixture was melt-kneaded (melt-mixed) using a single-screw extruder equipped with a 30 mm vent at a set temperature of 200 ° C., a rotation speed of 80 rpm, and a discharge rate of 10 kg / hour while being deaerated from the vent. Pellets of the resin composition were obtained. After the obtained pellets were dried at 80 ° C. for 3 hours, each of the above evaluations was performed. Table 3 shows the evaluation results.

[Examples 65 to 67]
(A) Polyacetal resin, (D) metal pigment, (E) lubricant, and (F) formaldehyde inhibitor were carried out in the same manner as in Example 24, except that the composition was as shown in Table 3. The evaluation results are shown in Table 3 below.

[Example 68]
(A) 100 parts by mass of the component (a-1) as a polyacetal resin, 0.60 parts by mass of a polyalkylene glycol compound (corresponding to the component (c-4)), and (F) as a formaldehyde inhibitor After blending 0.08 parts by mass of the component (f-1) with a mixer, 6.0 parts by mass of the component (d-13) as a metal pigment (D) was added to obtain a mixture. The obtained mixture was melt-kneaded (melt-mixed) using a single-screw extruder equipped with a 30 mm vent at a set temperature of 200 ° C., a rotation speed of 80 rpm, and a discharge rate of 10 kg / hour while being deaerated from the vent. Pellets of the resin composition were obtained. After drying the obtained pellets at 80 ° C. for 3 hours, each of the above evaluations was performed. The evaluation results are shown in Table 3 below.

  According to Table 3, in Examples 41 to 67 using the (D) metal pigment including the (C) polyalkylene glycol compound in which the mass ratio of oxygen to the mass of the entire compound is within a predetermined range, the polyalkylene glycol is not included. (D) Comparative Examples 41, 44, 46, 48, 52, and 53 using a metal pigment, and (D) a metal pigment containing a polyethylene glycol compound in which the mass ratio of oxygen in the entire compound is out of a predetermined range. It can be seen that higher glossiness is obtained as compared with Comparative Examples 42, 43, 45, 47 and 51 using No. In particular, in (E) Examples 64 to 67 in which liquid paraffin was further added as a lubricant, higher glossiness and FI value were obtained as compared with the case where no lubricant was added.

Also, from Table 3, Comparative Examples 42, 43, 45, 47 and 51 using the (D) metal pigment containing the polyethylene glycol compound in which the mass ratio of oxygen to the whole compound is out of the predetermined range are shown in Examples. It can be seen that the amount of formaldehyde generated is larger than that of. In addition, as compared with Example 68 in which the polyalkylene glycol compound (c-4) in which the mass ratio of oxygen to the entire mass of the compound was within a predetermined range was added separately, it can be seen that the example has excellent extrusion stability.
Furthermore, in Comparative Examples 49 and 50, (D) the result was that the FI value was low because the shape of the metal particles contained in the metal pigment was out of the predetermined range.

  As is clear from the evaluation results in Table 3, according to Examples 41 to 67, the metal particles having the specific shape and the metal pigment containing the specific polyalkylene glycol are used in the crystalline resin at a specific mass ratio. By performing the melt-kneading, a resin composition which generates a small amount of formaldehyde and can produce a molded article having an excellent metallic appearance can be obtained under a more stable melt-kneading condition. Further, the resin compositions of Examples 41 to 67 have good melt-kneading conditions during extrusion, good melt-kneading conditions during injection molding, and good retention stability, and have few appearance defects when formed into molded articles, The resin composition had a metal-like appearance with little volatilization of the organic solvent from the composition and an excellent metal appearance.

  The resin composition of the present invention has industrial applicability as a material for decorative parts.

Claims (7)

(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;
(C) 0.01 to 5 parts by mass of a polyalkylene glycol compound having a mass ratio of oxygen atoms to the mass of the entire compound of 1 to 36%,
A resin composition comprising: (A) 100 parts by mass of a polyacetal resin,
(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) the ratio of the mass of oxygen atoms to the total mass of the compound is 1 (D) 0.1 to 15 parts by mass of a metal pigment containing a polyalkylene glycol compound which is
A resin composition comprising:   The resin composition according to claim 2, wherein the proportion of the (B) metal particles contained in the (D) metal pigment is 70 to 95% by mass.   The resin composition according to any one of claims 1 to 3, wherein the (C) polyalkylene glycol compound has a number average molecular weight of 500 to 10,000.   The resin composition according to any one of claims 1 to 4, wherein the (C) polyalkylene glycol compound has a repeating unit derived from an oxyalkylene having 4 or more carbon atoms.   The resin composition according to any one of claims 1 to 5, wherein the (B) metal particles include aluminum.   The resin composition according to any one of claims 1 to 6, further comprising (E) a lubricant.

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