TW202124574A - Polyacetal resin composition and metal resin composition wherein the polyacetal resin composition contains polyacetal resin, nitrogen-containing compound, and fatty acid metal salt - Google Patents

Abstract

The object of the present invention is to provide a polyacetal resin composition that is excellent in extrusion stability, thermal stability, low warpage, and foreign matter suppression, and is thus excellent in metal powder dispersibility. The polyacetal resin composition of the present invention contains (A) 100 parts by mass of polyacetal resin, (B) 0.005 to 0.2 parts by mass of nitrogen-containing compound, and (C) 0.01 to 0.8 parts by mass of fatty acid metal salt, and the melt flow index measured under the condition of 190 DEG C and 2.16kg is greater than 60 g/10minutes and smaller than 200 g/10minutes, and the melting point is 153 to 162 DEG C. The ratio ((C)/(B)) of the content of the above (C) fatty acid metal salt to the content of the above-mentioned (B) nitrogen-containing compound is 1 to 15.

Description

Polyacetal resin composition and metal resin composition

The present invention relates to a polyacetal resin composition and a metal resin composition.

The polyacetal resin composition has well-balanced mechanical properties and excellent fatigue properties, so it is widely used in parts such as automobiles, electronic equipment, and electrical equipment. However, in recent years, polyacetal resin compositions have also been increasingly used as a binder for metal powder injection molding. As a technology for using polyacetal resin as a binder, for example, the following technology has been introduced (previous document 1) That is, the binder component contains polyacetal resin, polyolefin resin, and other polymers. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 2017-530029 [Patent Document 2] Japanese Patent Laid-Open No. 2011-32379

[The problem to be solved by the invention]

Here, the characteristics required for the polyacetal resin composition used as a binder for metal powder injection molding include: in order to uniformly disperse the metal powder in the polyacetal resin composition, the fluidity is required to be relatively high. High (high melt flow index (MI)); from the viewpoint of the operating environment, excellent thermal stability is required; and in order to suppress the influence on the final metal product, it is necessary to make the thermal stability or extrusion stability poor The content of foreign matter such as formaldehyde or carbides of additives generated during the manufacturing process is relatively low; furthermore, the obtained product needs to be low warpage. As a technique for improving thermal stability, for example, the following technique is introduced (Patent Document 2), namely, the polyacetal resin is formulated with two kinds of antioxidants, fatty acid calcium salt, formaldehyde reactive nitrogen-containing compound, and lubricant to improve heat resistance. , Solvent resistance, and acid resistance.

However, in the techniques described in Patent Documents 1 and 2, it cannot be said that the characteristics required for the above polyacetal resin composition are sufficient. Especially in Patent Document 2, the polyacetal resin composition has a relatively high MI. There is still room for improvement in the physical properties.

The object of the present invention is to provide a polyacetal resin composition and a metal resin composition. The polyacetal resin composition is excellent in extrusion stability, thermal stability, low warpage, and foreign matter suppression, and Dispersibility with metal powder is excellent; the metal resin composition includes metal powder and polyacetal resin composition, and is excellent in extrusion stability, thermal stability, and low warpage. The foreign matter content is low, and the metal The powder is effectively dispersed. [Technical means to solve the problem]

In order to solve the above-mentioned problems, the inventors have conducted intensive research and found that a polyacetal resin with a relatively high melt flow index and a low melting point contains a nitrogen-containing compound and a fatty acid metal salt in a predetermined content, and contains The polyacetal resin composition in which the content of the nitrogen compound and the fatty acid metal salt is set at a predetermined ratio can solve the above-mentioned problems, and the present invention has been completed.

That is, the present invention is as follows. [1] A polyacetal resin composition comprising (A) 100 parts by mass of polyacetal resin, (B) 0.005 to 0.2 parts by mass of nitrogen-containing compound, and (C) 0.01 to 0.8 parts by mass of fatty acid metal salt, and The melt flow index measured under the conditions of 190℃ and 2.16 kg is more than 60 g/10 minutes and less than 200 g/10 minutes, Melting point is 153～162℃, The ratio ((C)/(B)) of the content of the fatty acid metal salt (C) to the content of the nitrogen-containing compound (B) is 1-15. [2] The polyacetal resin composition of [1], wherein the ratio ((C)/(B)) of the content of the (C) fatty acid metal salt to the content of the nitrogen-containing compound (B) is 1-10. [3] The polyacetal resin composition of [1] or [2], wherein with respect to 100 parts by mass of the polyacetal resin (A) above, The content of the nitrogen-containing compound (B) is 0.005 to 0.1 parts by mass, and the content of the fatty acid metal salt (C) is 0.01 to 0.6 parts by mass. [4] The polyacetal resin composition according to any one of [1] to [3], which further contains 0.01 to 1.0 parts by mass of (D) antioxidant with respect to 100 parts by mass of the above-mentioned (A) polyacetal resin. [5] A metal resin composition comprising metal powder and the above-mentioned polyacetal resin composition according to any one of [1] to [4], and the content of the metal powder is 100% by mass of the above-mentioned metal resin composition The medium content is 70 to 95% by mass. [Effects of Invention]

According to the present invention, it is possible to provide a polyacetal resin composition and a metal resin composition. The polyacetal resin composition is excellent in extrusion stability, thermal stability, low warpage, and foreign matter suppression, and further It is excellent in dispersibility with metal powder; the above-mentioned metal resin composition includes a metal powder and a polyacetal resin composition, and is excellent in extrusion stability, thermal stability, and low warpage, and has a low content of foreign matter. The metal powder is effectively dispersed.

Hereinafter, embodiments of the present invention will be described in detail. In addition, the present invention is not limited to the following description, and can be implemented with various changes within the scope of the gist.

(Polyacetal resin composition) The polyacetal resin composition of this embodiment contains (A) 100 parts by mass of polyacetal resin, (B) 0.005 to 0.2 parts by mass of nitrogen-containing compound, and (C) 0.01 to 0.8 parts by mass of fatty acid metal salt. In addition, regarding the resin composition, the melt flow index measured under the conditions of 190°C and 2.16 kg is 60 g/10 minutes or more and less than 200 g/10 minutes, the melting point is 153 to 162°C, and (C ) The ratio ((C)/(B)) of the content of fatty acid metal salt to the content of (B) nitrogen-containing compound is 1-15. Thereby, the extrusion stability, thermal stability, low warpage property, and foreign matter suppression property at the time of manufacturing the polyacetal resin composition can be made excellent, and the dispersibility with metal powder can also be made excellent.

[(A) Polyacetal resin] (A) The polyacetal resin-based polyacetal homopolymer, polyacetal copolymer, or a mixture thereof in this embodiment. From the viewpoint of thermal stability, the (A) polyacetal resin in this embodiment is preferably a polyacetal copolymer. Polyacetal homopolymer is a polymer with oxymethylene in the main chain. Ester or ether groups can be used to block both ends of the polymer. Polyacetal homopolymers can be obtained by using formaldehyde and known molecular weight modifiers as raw materials. For example, a known onium salt-based polymerization catalyst can be used, a hydrocarbon etc. as a solvent and a known slurry method, such as Japanese Patent The polymerization method described in Japanese Patent Publication No. 47-6420 or Japanese Patent Publication No. 47-10059 is obtained from these raw materials. Furthermore, the polyacetal homopolymer preferably has 99.8 mol% or more of the main chain excluding both ends composed of oxymethylene groups, and more preferably, the main chain excluding both ends is composed only of oxymethylene groups. Constructor.

The polyacetal copolymer is a polyacetal resin obtained by copolymerizing trioxane, cyclic ether and/or cyclic formal in the presence of a polymerization catalyst. The so-called trioxane refers to a cyclic trimer of formaldehyde, which is generally obtained by reacting an aqueous solution of formalin in the presence of an acidic catalyst. The trioxane may contain impurities that cause chain transfer such as water, methanol, formic acid, methyl formate, etc., and therefore, it is preferable to remove these impurities and purify, for example, by a method such as distillation. In this case, it is preferable to set the total amount of impurities for chain transfer to 1×10 ^-3 mol or less, and more preferably 0.5×10 ^-3 mol or less to 1 mol of trioxane . By reducing the amount of impurities as the above-mentioned value, the polymerization reaction speed can be sufficiently increased in practical applications, so that the resulting polymer can obtain excellent thermal stability.

Cyclic ether and/or cyclic formal are components that can be copolymerized with the above-mentioned trioxane. Examples include ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, epibromohydrin, and benzene oxide. Ethylene, oxetane, 1,3-dioxolane, ethylene glycol formal, propylene glycol formal, diethylene glycol formal, triethylene glycol formal, 1,4-butanediol Formal, 1,5-pentanediol formal, 1,6-hexanediol formal, etc. In particular, 1,3-dioxolane and 1,4-butanediol formal are preferred. These may be used individually by 1 type, and may use 2 or more types together.

The amount of cyclic ether and/or cyclic formal added is preferably 5.0 to 20.0 mol% (melting point: 162°C to 153°C), more preferably 6.0 to 13.0 mol% relative to 1 mol of the above trioxane % (Melting point is 161°C to 155°C), more preferably 6.0 to 10.0 mol% (melting point is 161°C to 157°C). If the melting point is lower than 153°C, the extrusion stability of the polyacetal resin composition, the dispersibility of the metal powder, and the warpage of the press-formed product mixed with the metal powder will deteriorate; if the melting point is higher than 162°C, As a result, the thermal stability and the warpage of the press-formed product of a mixture with metal powder deteriorate.

Examples of polymerization catalysts include boric acid, tin, titanium, phosphorus, arsenic, and antimony compounds represented by Lewis acids, especially boron trifluoride, boron trifluoride hydrate, and organic compounds containing oxygen or sulfur atoms. The coordination complex of the compound and boron trifluoride is preferred. For example, the following can be cited as suitable examples: boron trifluoride, boron trifluoride diethyl ether, and boron trifluoride di-n-butyl ether. These may be used individually by 1 type, and may use 2 or more types together.

The addition amount of the polymerization catalyst is preferably in the range of 0.1×10 ^-5 to 0.1×10 ^-3 mol, and more preferably 0.3×10 ^-5 to 0.5×10 ^{-4 mol with respect to 1 mol of the above trioxane} The range of ears is more preferably the range of 0.5×10 ^-5 to 0.4×10 ^-4 moles. When the addition amount of the polymerization catalyst is within the above range, the polymerization reaction can be carried out stably for a long time.

In the production of polyacetal copolymers, the deactivation of the polymerization catalyst is carried out by the following method: the polyacetal resin obtained by the polymerization reaction is poured into at least one of the following catalysts and deactivators In the aqueous or organic solvent solution, it is generally stirred in the slurry state for several minutes to several hours. As the above-mentioned catalyst neutralization and deactivator, there are ammonia, triethylamine, tri-n-butylamine and other amines, or alkali metals or Alkaline earth metal hydroxides, inorganic acid salts, organic acid salts, etc. The slurry after catalyst neutralization and deactivation is filtered and washed to remove unreacted monomers, catalyst neutralization deactivator, and catalyst neutralization salt, and then dried.

In addition, for the deactivation of the polymerization catalyst, it is also possible to use: a method of inactivating the polymerization catalyst by contacting vapors such as ammonia, triethylamine, etc. with the polyacetal copolymer; or making hindered amines, triphenylphosphine, and A method of contacting at least one of calcium hydroxide and the like with polyacetal resin in a mixer to deactivate the catalyst.

In addition, the polymerization catalyst is not deactivated, and the polyacetal copolymer is heated under an inert gas atmosphere at a temperature below the melting point of the polyacetal copolymer, whereby the polyacetal copolymer in which the polymerization catalyst is reduced by volatilization can also be used The following terminal stabilization treatment of this embodiment is performed. Regarding the above deactivation operation of the polymerization catalyst and the volatilization reduction operation of the polymerization catalyst, if necessary, the polyacetal resin obtained by the polymerization reaction may be pulverized.

The terminal stabilization treatment of the obtained (A) polyacetal resin was decomposed and removed the unstable terminal part by the following method. As a method of decomposing and removing the unstable end portion, for example, a single screw extruder with a vent hole or a twin-screw extruder with a vent hole can be used, where there is a known alkali that can decompose the unstable end portion. When the substance is used as a cutting agent, the polyacetal resin is melted to decompose and remove the unstable end. As the above-mentioned alkaline substance, there are ammonia, triethylamine, tributylamine and other fatty acid amines, and alkalis represented by calcium hydroxide Metal or alkaline earth metal hydroxides, inorganic weak acid salts, organic weak acid salts, etc.

The melt flow index (MI) of (A) polyacetal resin of this embodiment is measured at 190°C and 2.16 kg in accordance with ASTM-D-1238-57T. The melt flow index is preferably 60 g/10 Minutes or more and less than 200 g/10 minutes, more preferably 60 g/10 minutes or more and less than 160 g/10 minutes, and still more preferably 70 g/10 minutes or more and less than 140 g/10 minutes. By setting the melt flow index to 60 g/10 minutes or more, the low warpage and dispersibility with metal powders are improved; by setting the melt flow index to less than 200 g/10 minutes, the thermal stability is improved Performance, low warpage, foreign matter suppression, and dispersibility with metal powder, and can also improve the extrusion stability when polymerizing (A) polyacetal resin. Furthermore, (A) the melt flow index of the polyacetal resin can be operated by increasing the amount of the molecular weight regulator added during polymerization to increase the melt flow index. The melting point of the (A) polyacetal resin of this embodiment is preferably 153°C or higher and 162°C or lower, more preferably 155°C or higher and 161°C or lower, and still more preferably 157°C or higher and 161°C or lower. By setting the melting point to 153°C or higher, thermal stability, low warpage, foreign matter suppression, and dispersibility with metal powder can be improved, and extrusion during polymerization of (A) polyacetal resin can also be improved. Stability: By setting the melting point to 162°C or less, thermal stability and low warpage can be improved. Furthermore, (A) the melting point of the polyacetal resin can be operated by increasing the amount of cyclic ether and/or cyclic formal added during polymerization to decrease the melting point.

[(B) Nitrogen-containing compound] The polyacetal resin composition of this embodiment contains (B) a nitrogen-containing compound, and (C) a fatty acid metal salt is complementary to each other to improve thermal stability. The nitrogen-containing compound (B) is not particularly limited, and examples thereof include polyamide resins, amide compounds, urea derivatives, trisulfide derivatives, and the like. One of these can be used, or two or more of them can be used in combination. The polyamide resin is not particularly limited, and examples thereof include nylon 6, nylon 11, nylon obtained by condensation of diamine and dicarboxylic acid, condensation of amino acid, ring-opening polymerization of lactam, etc. 12. Nylon 66, nylon 6, 10, nylon 6/6, 10, nylon 6/6, 6, nylon 6, 6/6, 10, nylon 6/6, 6/6, 10, poly-β-alanine Wait.

The amide compound is not particularly limited, and examples include: aliphatic monocarboxylic acid, aliphatic dicarboxylic acid, aromatic monocarboxylic acid or aromatic dicarboxylic acid and aliphatic monoamine, aliphatic diamine, aromatic Stearyl amide, stearyl oleate, stearyl erucamide, ethylenediamine-distearate, ethylenediamine produced by monoamines and aromatic diamines -Dibehenic acid amide, hexamethylene diamine-distearic acid amide, ethylenediamine-dierucic acid amide, xylylenediamine-dierucamide, bis(xylylenediamine) Diamine-stearic acid amide), sebacic acid amide and the like.

It does not specifically limit as a urea derivative, For example, N-phenylurea, N,N'-diphenylurea, N-phenylthiourea, N,N'-diphenylthiourea, etc. are mentioned.

There are no particular limitations on the three derivatives, and examples include melamine, benzoguanamine, N-phenylmelamine, melem, N,N'-diphenylmelamine, N-methylolmelamine, N , N'-trimethylol melamine, 2,4-diamino-6-cyclohexyl tris, melam, etc.

The content of the (B) nitrogen-containing compound is 0.005 to 0.2 parts by mass, preferably 0.005 to 0.1 parts by mass relative to 100 parts by mass of the polyacetal resin. By setting the content to 0.005 parts by mass or more, thermal stability and low warpage can be improved, and the content of foreign matter can be suppressed. In addition, by setting the content to 0.2 parts by mass or less, low warpage properties can be improved, and the content of foreign matter can be suppressed.

[(C) Fatty acid metal salt] The polyacetal resin composition of the present embodiment contains (C) a fatty acid metal salt, and (B) a nitrogen-containing compound is complementary to each other, and can maintain long-term thermal stability. The fatty acid metal salt (C) is not particularly limited. For example, the following fatty acid metal salt can be mentioned, the fatty acid metal salt is composed of a saturated or unsaturated fatty acid having 10 to 35 carbon atoms or a fatty acid substituted with a hydroxyl group, and an alkali metal or alkaline earth Obtained from metal-like hydroxides, oxides or chlorides.

Examples of fatty acids of fatty acid metal salts include capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid, nonadenic acid, arachidic acid, Behenic acid, lignoceric acid, ceric acid, twenty-seven acid, montanic acid, undecylenic acid, oleic acid, elaidic acid, cetenoic acid, erucic acid, basilic acid, sorbic acid, linseed oil Acid, linolenic acid, arachidic acid, propionic acid, stearylic acid, 12-hydroxylauric acid, 3-hydroxydecanoic acid, 16-hydroxyhexadecanoic acid, 10-hydroxyhexadecanoic acid, 12-hydroxydecanoic acid Octanoic acid, 10-hydroxy-8-octadecanoic acid, etc. In addition, the metal compound is a hydroxide or chloride of alkali metals such as sodium, lithium, potassium, calcium, magnesium, barium, zinc, aluminum, and strontium, and alkaline earth metals. Among them, preferably, the fatty acid is myristic acid, palmitic acid, and stearic acid, and the metal compound is calcium hydroxide, oxide, and chloride. As specific examples of fatty acid metal salts, there are calcium myristate, potassium palmitate, and calcium stearate.

The content of the (C) fatty acid metal salt is 0.01 to 0.8 parts by mass, preferably 0.01 to 0.6 parts by mass relative to 100 parts by mass of the polyacetal resin. By setting the content to 0.01 parts by mass or more, thermal stability and low warpage can be improved, and the content of foreign matter can be suppressed. In addition, by setting the content to 0.8 parts by mass or less, thermal stability and low warpage can be improved, and the content of foreign matter can be suppressed.

[The ratio of the content of (C) fatty acid metal salt to the content of (B) nitrogen-containing compound] In this embodiment, it is important that the ratio of the content of (C) fatty acid metal salt to the content of (B) nitrogen-containing compound is within a specific range. Specifically, the ratio is 1-15, preferably 1. ~10. By setting the ratio to 1 or more, thermal stability and low warpage can be improved, and the content of foreign matter can be suppressed. In addition, by setting the ratio to 15 or less, thermal stability and low warpage can be improved, and the content of foreign matter can be suppressed.

[Other additives] In this embodiment, the other additives that can be added to the polyacetal resin composition are not limited as long as the effects of the present invention are not impaired. Preferred additives include antioxidants. Examples of antioxidants include: n-octadecyl 3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate, 3-(3'-methyl-5' -Tertiary butyl-4'-hydroxyphenyl) n-octadecyl propionate, 3-(3',5'-di-tert-butyl-4'-hydroxyphenyl) n-tetradecyl propionate Base ester, 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), 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, triethylene glycol-bis( 3-(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate), methylene tetrakis(3-(3'-tert-butyl-4-hydroxyphenyl) propionate )Methane, N,N'-bis(3-(3,5-di-tert-butyl-4-hydroxyphenol)propionyl)hydrazine, N,N'-tetramethylene-bis-3-(3 '-Methyl-5'-tert-butyl-4-hydroxyphenol) propionyl diamine, N,N'-bis-3-(3',5'-di-tert-butyl-4-hydroxyphenol ) Propyl hexamethylene diamine, 3-(N-O-hydroxybenzyl)amine-1,2,4-triazole, N,N'-bis(2-(3-(3,5 -Dibutyl-4-hydroxyphenyl)propionyloxy)ethyl)oxyamide, N,N'-hexamethylene-bis(3-3,5-tert-butyl-4-hydroxyl Phenyl) propionamide) and so on. One of these antioxidants may be used, or two or more of them may be used in combination.

The content of the antioxidant is 0.01 to 1.0 part by mass relative to 100 parts by mass of the polyacetal resin, preferably 0.05 to 0.5 part by mass. By making the content within the above range, the thermal stability can be improved.

[Characteristics of polyacetal resin composition] The melt flow index (MI) of the polyacetal resin composition of this embodiment is measured at 190°C and 2.16 kg in accordance with ASTM-D-1238-57T, and the melt flow index is 60 g/10 minutes or more And it is less than 200 g/10 minutes, preferably 60 g/10 minutes or more and less than 160 g/10 minutes, more preferably 70 g/10 minutes or more and less than 140 g/10 minutes. By setting the melt flow index to 60 g/10 minutes or more, low warpage, dispersibility with metal powder, and foreign matter suppression are improved; by setting the melt flow index to less than 200 g/10 minutes, It improves extrusion stability, thermal stability, low warpage, foreign matter suppression, and dispersibility with metal powder. The melting point of the polyacetal resin composition of this embodiment is 153°C or higher and 162°C or lower, preferably 155°C or higher and 161°C or lower, and more preferably 157°C or higher and 161°C or lower. By setting the melting point to 153°C or higher, extrusion stability, low warpage, dispersibility with metal powder, and foreign matter suppression are improved. By setting the melting point to 162°C or lower, thermal stability, foreign matter suppression, and low warpage can be improved.

[Manufacturing method of polyacetal resin composition] In this embodiment, the manufacturing method of a polyacetal resin composition is not specifically limited, It can manufacture by a well-known method. Specifically, for example, after mixing the above-mentioned (A) to (C) components, optional additives, etc., using a Henschel mixer, drum, V-shaped mixer, etc., a single-screw extruder or a double-screw extruder is used. Melting and kneading with kneaders such as the ejector, heating roller, kneader, and Banbury mixer can produce polyacetal resin compositions, thereby obtaining products in various forms such as linear and granular shapes.

(Metal resin composition) The metal resin composition of the present embodiment includes a metal powder and the above-mentioned polyacetal resin composition, and the content of the metal powder is 70 to 95% by mass in 100% by mass of the metal resin composition. Thereby, extrusion stability, thermal stability, low warpage, and foreign matter suppression properties can be made excellent, and the dispersibility with metal powder can also be made excellent. Furthermore, the metal resin composition can be used for metal powder injection molding. As the metal powder, in order to impart functionality, it is preferably metal or ceramic. Specific metals include aluminum, magnesium, barium, calcium, cobalt, zinc, copper, nickel, iron, silicon, titanium, tungsten, and metal compounds and metal alloys based on these. Here, not only the completed alloy can be used, but also a mixture of various alloy components can be used.

Specific ceramics include oxides such as zinc oxide, aluminum oxide, and zirconium oxide; hydroxides such as hydroxyphosphate lime; carbides such as silicon carbide; nitrides such as silicon nitride or boron nitride; and halides such as fluorite ; Silicates such as talc; titanates such as barium titanate or lead zirconate titanate; carbonates; phosphates; ferrites; high-temperature superconducting materials, etc. One of these inorganic substances can be used alone, or several inorganic substances such as multiple metals or metal alloys, or ceramics can be used in combination. As a particularly preferred metal or alloy metal, titanium alloy or SUS316L can be cited; as ceramics, Al ₂ O ₃ and ZrO _{2 can be} cited. The particle size of these metals is preferably 30 μm or less, more preferably 20 μm or less.

In this embodiment, the content of the metal powder in the metal resin composition containing the metal powder and the polyacetal resin composition is 70 to 95% by mass, preferably 80 to 90% by mass. In addition to the metal powder and the aforementioned polyacetal resin composition, the metal resin composition can optionally be added with additives. In 100% by mass of the metal resin composition, the content of the additives is preferably 5% by mass or less, more preferably 2 Mass% or less, more preferably 0 mass %.

In this embodiment, the dispersibility of the metal powder in the metal resin composition is measured by the evaluation method described in the following examples, and is preferably 1.20 or less, more preferably 1.15 or less, and still more preferably 1.10 the following. Thereby, a good molded body can be obtained from the metal resin composition.

[Manufacturing method of metal resin composition] In this embodiment, the manufacturing method of a metal resin composition is not specifically limited, It can manufacture by a well-known method. Specifically, for example, after mixing the above-mentioned metal powder and the polyacetal resin composition with a Henschel mixer, a drum, a V-shaped mixer, etc., a single-screw extruder or a twin-screw extruder is used Kneaders such as heating rolls, kneaders, and Banbury mixers are melted and kneaded in a semi-molten state, whereby metal resin compositions can be produced, and products in various forms such as linear and granular shapes can be obtained. [Example]

Hereinafter, the present invention will be described in detail with specific examples and comparative examples, and the present invention is not limited to the following examples. In addition, the measurement methods of terms and characteristics in the examples and comparative examples are as follows.

[(A) Polyacetal resin] (A-1) The temperature of a jacketed biaxial slurry type continuous polymerization reactor (manufactured by Kurimoto Iron Works Co., Ltd., diameter 2B, L/D=14.8) through which the heat medium can pass is adjusted to 80°C. The catalyst mixture was used as the polymerization catalyst to adjust the molecular weight at 69 g/hr, trioxane at 3500 g/hr, 1,3-dioxolane at 202 g/hr, and methylal as the molecular weight. The agent was continuously supplied to the polymerization reactor at 7.1 g/hr to perform polymerization, and the catalyst preparation liquid was obtained by diluting boron trifluoride di-n-butyl ether with cyclohexane to 0.26% by mass. The product discharged from the polymerization reactor was poured into a 0.5% by mass triethylamine aqueous solution to deactivate the polymerization catalyst, and then filtered, washed, and dried. Then, it was supplied to a twin-screw extruder (L/D=40) with vents set at 200°C, and 0.8% by mass of triethylamine aqueous solution was added to 20 ppm in terms of nitrogen content. The terminal stabilization zone is stabilized while degassing at 90 kPa under reduced pressure, and pelletized by a pelletizer. Then, it was dried at 100°C for 2 hr to obtain (A-1) polyacetal resin. The obtained polyacetal resin (A-1) had a melting point of 159°C and a melt flow index of 71 g/10 minutes.

(A-2) Except that the flow rate of methylal as a molecular weight modifier was set to 9.4 g/hr, (A-2) polyacetal resin was produced in the same manner as (A-1) the method of producing polyacetal resin. The obtained polyacetal resin (A-2) had a melting point of 159°C and a melt flow index of 121 g/10 minutes.

(A-3) Except that the flow rate of the methylal as the molecular weight modifier was 10.6 g/hr, the (A-3) polyacetal resin was produced in the same manner as the method for producing the (A-1) polyacetal resin. The obtained (A-3) polyacetal resin had a melting point of 159°C and a melt flow index of 180 g/10 minutes.

(A-4) The flow rate of 1,3-dioxolane was set to 361 g/hr, and the flow rate of methylal as a molecular weight regulator was set to 9.4 g/hr. In addition, polycondensation with (A-1) (A-4) Polyacetal resin is produced in the same manner as the production method of aldehyde resin. The obtained polyacetal resin (A-4) had a melting point of 156°C and a melt flow index of 120 g/10 minutes.

(A-5) The flow rate of 1,3-dioxolane was set to 462 g/hr, and the flow rate of methylal as a molecular weight regulator was set to 9.4 g/hr. In addition, polycondensation with (A-1) The manufacturing method of aldehyde resin is similarly manufactured (A-5) polyacetal resin. The obtained (A-5) polyacetal resin had a melting point of 154°C and a melt flow index of 121 g/10 minutes.

(A-6) Except that the flow rate of methylal as a molecular weight modifier was set to 4.4 g/hr, (A-6) polyacetal resin was produced in the same manner as (A-1) the production method of polyacetal resin. The obtained polyacetal resin (A-6) had a melting point of 159°C and a melt flow index of 31 g/10 minutes.

(A-7) Except that the flow rate of the methylal as the molecular weight modifier was set to 11.6 g/hr, the (A-7) polyacetal resin was produced in the same manner as the method for producing the (A-1) polyacetal resin. The obtained polyacetal resin (A-7) had a melting point of 159°C and a melt flow index of 211 g/10 minutes.

(A-8) The flow rate of 1,3-dioxolane was set to 662 g/hr, and the flow rate of methylal as a molecular weight regulator was set to 9.4 g/hr. In addition, polycondensation with (A-1) (A-8) Polyacetal resin is produced in the same manner as the production method of aldehyde resin. The obtained polyacetal resin (A-8) had a melting point of 152°C and a melt flow index of 120 g/10 minutes.

(A-9) Set the flow rate of 1,3-dioxolane to 121 g/hr, and set the flow rate of methylal as a molecular weight regulator to 9.4 g/hr. Otherwise, polycondensate with (A-1) The manufacturing method of aldehyde resin is similarly manufactured (A-9) polyacetal resin. The obtained polyacetal resin (A-9) had a melting point of 164°C and a melt flow index of 120 g/10 minutes.

[(B) Nitrogen-containing compound] (B-1) Nylon 66 (molecular weight 10000) (B-2) Melamine (manufactured by Nissan Chemical Industry Co., Ltd.)

[(C) Fatty acid metal salt] (C-1) Calcium stearate (C-2) Calcium montanate

[Other additives] (D-1) Antioxidant: Triethylene glycol-bis-[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate] (Irganox245 manufactured by BASF Co., Ltd.)

[Melt Flow Index (MI)] According to ASTM-D-1238, MI (melt flow index: g/10 minutes) is measured at 190°C and 2160 g using MELT INDEXER manufactured by Toyo Seiki.

[Melting point] Using a differential calorimeter (manufactured by PerkinElmer, DSC-2C), the melted sample was heated to 200°C and cooled to 100°C, and then heated again at a rate of 2.5°C/min. This process The peak temperature of the exothermic spectrum generated in the middle is regarded as the melting point.

[Thermal stability] The polyacetal resin composition (3±0.01 g) obtained by extrusion is heated to 230°C under a nitrogen atmosphere (50 nl/hr) to melt, and the formaldehyde generated within the residence time of 2-30 minutes The gas is absorbed to a 1 mol/L sodium sulfite aqueous solution to generate sodium hydroxide, and this sodium hydroxide is titrated with sulfuric acid of 1/100 equivalent concentration to obtain the amount of formaldehyde gas. In this titration, thymolphthalein was used as an indicator, and the point when the blue color became colorless was set as the end point.

[Extrusion stability] Visually confirm 2.5 kg of pellets of the polyacetal resin composition obtained by extrusion. The object in the shape where the pellets are connected is called contiguous pellets, and the contiguous pellets are taken out and their weight is measured. Calculate the proportion and score. The larger the score, the better the extrusion stability (the greater the ratio of continuous pellets, the worse the extrusion stability). 3: No continuous grain 2: The proportion of continuous grains is less than 10% 1: The proportion of continuous grain is more than 50%

[foreign body] In a hot press (manufactured by Matsuda Manufacturing Co., Ltd.) set at 220°C, the polyacetal resin composition was press-formed into a flat plate using 180 mm×180 mm×2 mm (thickness) as a mold frame. For both sides of the forming plate, use a magnifying glass to determine the number of foreign objects above 0.1 mm. The foreign body has black, brown, red, yellow and other colors, and the foreign body of all colors is calculated.

[Dispersibility of metal powder] Using a Laboplastomill heated to a set temperature of 170°C, 70 g of 20 μm SUS316L powder and 30 g of the polyacetal resin composition obtained in the following examples and comparative examples were mixed in a semi-melt Mix for 30 minutes in the state to produce a sugar-like solid (36 cm ^{3 in} volume). From the obtained solid material, 5 parts were arbitrarily selected, and 10 g of each was cut out. Then, the polyacetal resin composition was degreased in an electric furnace set at a temperature of 550°C, and the weight of the remaining metal was measured. Also, find the ratio of the maximum weight to the minimum weight. The smaller the ratio, the better the dispersion.

[Warpage property of metal resin composition molded product] Using a Laboplastomill heated to a set temperature of 170°C, 70 g of 20 μm SUS316L powder, and the polyacetal resin composition obtained in the following examples and comparative examples 30 g was mixed in a semi-molten state for 30 minutes to produce a glutinous sugar-like solid (36 cm ^{3 in} volume). In a hot press set at 250°C (manufactured by Matsuda Manufacturing Co., Ltd.), the obtained solid object was press-formed into a flat plate using 180 mm×180 mm×2 mm (thickness) as a mold frame. When the two sides of one side of the forming board are fixed on the table, the side on the opposite side will swell. Therefore, the swelling amount (mm) at the position where the forming board swells the highest from the surface of the table is measured as the warpage. The smaller the swelling amount, the better the warpage.

[Example 1] Add 0.05 parts by mass of (B-1) nylon 66 and 0.3 parts by mass of (C-1) calcium stearate to 100 parts by mass of (A-1) polyacetal resin and mix them uniformly. In a twin-screw extruder (L/D=40) with vents at 200°C, pelletizing was performed while degassing under reduced pressure at 90 kPa. It was then dried at 100°C for 2 hr. The obtained pellets were evaluated, and the results are shown in Table 1.

[Examples 2-18] According to the composition described in Table 1, the same operation as in Example 1 was carried out. The obtained pellets were evaluated, and the results are shown in Table 1.

[Comparative Examples 1-11] According to the composition described in Table 2, the same operation as in Example 1 was carried out. The obtained pellets were evaluated, and the results are shown in Table 2.

[Table 1] Example-1 Example-2 Example-3 Example-4 Example-5 Example-6 Example-7 Example-8 Example-9 Example-10 Example-11 Example-12 Example-13 Example-14 Example-15 Example-16 Example-17 Example-18 Polyacetal A-1 (phr) 100 100 A-2 (phr) 100 100 100 100 100 100 100 100 100 100 100 A-3 (phr) 100 100 A-4 (phr) 100 A-5 (phr) 100 100 A-6 (phr) A-7 (phr) A-8 (phr) A-9 (phr) Nitrogen compounds B-1 (phr) 0.05 0.05 0.01 0.15 0.01 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.1 0.15 B-2 (phr) 0.05 Fatty acid metal salt C-1 (phr) 0.3 0.3 0.14 0.3 0.3 0.02 0.7 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.6 0.15 0.2 C-2 (phr) 0.3 Antioxidants D-1 (phr) 0.3 0.3 0.3 0.3 C/B ratio - 6 6 14 2 6 2 14 6 6 6 6 6 6 6 6 12 1.5 1.3 combination Melting point °C 159.3 159.2 159.1 159.3 159.2 159.1 159.3 159.1 159.2 156.3 154.2 159.3 159.2 159.3 154.1 159.1 159.2 159.1 MI (g/10 minutes) 71.3 122 123 121 124 122 123 121 183 123 122 123 73 182 122 121 124 123 Extrusion stability - 3 3 3 3 2 3 3 3 2 2 2 3 3 3 3 3 3 3 Thermal stability (ppm) 122 180 160 142 150 145 155 143 157 118 98 72 68 73 69 167 140 110 foreign body (Number) 1 2 4 5 1 1 5 1 2 1 1 1 1 1 1 5 4 5 Dispersibility of metal powder Max/min ratio - 1.04 1.05 1.04 1.06 1.04 1.05 1.05 1.04 1.04 1.08 1.06 1.03 1.02 1.04 1.01 1.06 1.05 1.06 Warpage of metal resin composition molded products (mm) 0.14 0.11 0.10 0.09 0.09 0.11 0.12 0.09 0.09 0.18 0.16 0.08 0.07 0.09 0.07 0.11 0.12 0.10

[Table 2] Comparative example-1 Comparative example-2 Comparative example-3 Comparative example-4 Comparative example-5 Comparative example-6 Comparative example-7 Comparative example-8 Comparative example-9 Comparative example-10 Comparative example-11 Polyacetal A-1 (phr) A-2 (phr) 100 100 100 100 100 100 100 A-3 (phr) A-4 (phr) A-5 (phr) A-6 (phr) 100 A-7 (phr) 100 A-8 (phr) 100 A-9 (phr) 100 Nitrogen compounds B-1 (phr) 0.05 0.05 0.05 0.05 0.002 0.25 0.05 0.05 0.1 0.15 0.03 B-2 (phr) Fatty acid metal salt C-1 (phr) 0.3 0.3 0.3 0.3 0.3 0.3 0.005 0.9 0.08 0.11 0.6 C-2 (phr) Antioxidants D-1 (phr) C/B ratio - 6 6 6 6 150 1.2 0.1 18 0.8 0.73 20 combination Melting point °C 159.2 159.3 152.1 164.3 159.3 159.1 159.3 159.2 159.4 159.1 159.2 MI (g/10 minutes) 32 214 122 123 124 121 122 123 121 124 123 Extrusion stability - 3 1 1 3 3 3 3 3 3 3 3 Thermal stability (ppm) 101 862 80 520 1290 132 792 1060 530 663 980 foreign body (Number) 12 19 twenty one 12 17 68 14 30 26 25 30 Dispersibility of metal powder Max/min ratio - 1.67 1.24 1.18 1.06 1.05 1.09 1.06 1.05 1.07 1.08 1.05 Warpage of metal resin composition molded products (mm) 1.82 1.75 0.86 0.56 0.31 0.34 0.34 0.30 0.34 0.31 0.32

According to the evaluation results of Table 1 and Table 2 above, it is clear that the examples are excellent in thermal stability, extrusion stability, low warpage, and foreign matter suppression, and furthermore, are also excellent in dispersibility with metal powders. The above embodiment contains (A) polyacetal resin, (B) nitrogen-containing compound, and (C) fatty acid metal salt in specified content, the melt flow index and melting point are within the specified range, and (C) fatty acid metal salt content The ratio to the content of (B) nitrogen-containing compound is within the specified range. [Industrial availability]

According to the present invention, it is possible to provide a polyacetal resin composition and a metal resin composition. The polyacetal resin composition is excellent in extrusion stability, thermal stability, low warpage, and foreign matter suppression, and furthermore It is excellent in dispersibility with metal powder; the above-mentioned metal resin composition includes a metal powder and a polyacetal resin composition, and is excellent in extrusion stability, thermal stability, and low warpage, and has a low content of foreign matter. The metal powder is effectively dispersed.

Claims (5)

A polyacetal resin composition comprising (A) 100 parts by mass of polyacetal resin, (B) 0.005 to 0.2 parts by mass of nitrogen-containing compound, and (C) 0.01 to 0.8 parts by mass of fatty acid metal salt, and The melt flow index measured under the conditions of 190℃ and 2.16 kg is more than 60 g/10 minutes and less than 200 g/10 minutes, Melting point is 153～162℃, The ratio ((C)/(B)) of the content of the fatty acid metal salt (C) to the content of the nitrogen-containing compound (B) is 1-15. The polyacetal resin composition of claim 1, wherein the ratio ((C)/(B)) of the content of the fatty acid metal salt (C) to the content of the nitrogen-containing compound (B) is 1-10. The polyacetal resin composition of claim 1 or 2, wherein with respect to 100 parts by mass of the polyacetal resin (A) above, The content of the nitrogen-containing compound (B) is 0.005 to 0.1 parts by mass, and the content of the fatty acid metal salt (C) is 0.01 to 0.6 parts by mass. The polyacetal resin composition according to any one of claims 1 to 3, which further contains 0.01 to 1.0 parts by mass of (D) antioxidant with respect to 100 parts by mass of the (A) polyacetal resin. A metal resin composition comprising metal powder and the above-mentioned polyacetal resin composition according to any one of claims 1 to 4, and the content of the metal powder in 100% by mass of the above-mentioned metal resin composition 70 to 95% by mass.