Polyacetal resin composition

Abstract

According to the present invention, a polyacetal resin composition having high hot water resistance and excellent productivity can be provided. The polyacetal resin composition of the present invention is as follows: relative to 100 parts by mass of (A) polyacetal resin, (B) glass fiber surface-treated with a blocked isocyanate compound, an aminosilane coupling agent and an epoxy resin in an amount of 1 part by mass or more and 100 parts by mass or less; (C) at least one organic metal compound selected from organic metal compounds in an amount of 0.001 parts by mass or more and 2 parts by mass or less, wherein the organic metal compound is an organic metal compound having a metal selected from Zn, Sn and Pb; and (D) a triazine derivative having a nitrogen-containing functional group in an amount of 0.002 parts by mass or more and 10 parts by mass or less.

Description

Technical Field

[0001] The present invention relates to polyacetal resin compositions. Background Art

[0002] Polyacetal resin has excellent properties in terms of mechanical properties, thermal properties, electrical properties, sliding properties, moldability, impact resistance, dimensional stability of molded products, etc., and is widely used as structural materials and mechanism parts for electrical equipment, automobile parts, precision machinery parts, etc. In addition, in order to improve the mechanical properties of polyacetal resin, such as strength and rigidity, it is known to mix reinforcing materials such as glass-based inorganic fillers.

[0003] However, polyacetal resin lacks activity, and glass-based inorganic fillers also lack activity. Therefore, when simply mixing glass-based inorganic fillers in polyacetal resin and melt-kneading, the adhesion of the two becomes insufficient, and the improvement of mechanical properties as expected cannot be obtained in most cases. Therefore, various methods for improving the adhesion of polyacetal resin and glass-based inorganic fillers and improving mechanical properties have been proposed.

[0004] For example, there are known methods of adding a glass-based inorganic filler and a borane compound to a polyacetal resin (see Patent Document 1), and further surface-treating the glass-based inorganic filler with a blocked isocyanate or a specific silane compound (see Patent Document 2).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 9-151298

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 3-79631 Summary of the invention

[0009] Problem that the invention aims to solve

[0010] According to these methods, by increasing the chemical activity of the glass-based inorganic filler, the tensile strength, tensile elongation, bending strength, impact resistance, and hot water resistance of the polyacetal resin mixed with the glass-based inorganic filler can be improved. However, if the feed rate of the glass-based inorganic filler (especially glass fibers such as chopped fibers and rovings) is increased in order to improve productivity, the glass fibers sometimes become fluffy during feeding, which results in a problem of hindering stable production.

[0011] On the other hand, further improvement in hot water resistance of polyacetal resins blended with glass-based inorganic fillers is also required.

[0012] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a polyacetal resin composition having high hot water resistance and excellent productivity.

[0013] Solutions for solving problems

[0014] The objects of the present invention are achieved as follows.

[0015] (1) A polyacetal resin composition comprising, relative to 100 parts by mass of (A) a polyacetal resin:

[0016] (B) 1 part by mass or more and 100 parts by mass or less of glass fibers surface-treated with a blocked isocyanate compound, an aminosilane coupling agent, and an epoxy resin;

[0017] (C) 0.001 parts by mass or more and 2 parts by mass or less of an organometallic compound having a metal selected from the group consisting of Zn, Sn, and Pb; and

[0018] (D) 0.002 parts by mass or more and 10 parts by mass or less of a triazine derivative having a nitrogen-containing functional group.

[0019] (2) The polyacetal resin composition according to item 1 above, wherein the organometallic compound having a metal selected from the group consisting of Zn, Sn and Pb in (C) above is a metal carboxylate.

[0020] (3) The polyacetal resin composition according to item 1 above, wherein the organometallic compound having a metal selected from the group consisting of Zn, Sn and Pb in (C) above is a mixture of a carboxylic acid and an inorganic metal compound.

[0021] (4) The polyacetal resin composition according to any one of 1 to 3 above, wherein the triazine derivative having a nitrogen-containing functional group (D) is melamine.

[0022] Effects of the Invention

[0023] According to the present invention, a polyacetal resin composition having high hot water resistance and excellent productivity can be provided. DETAILED DESCRIPTION

[0024] Hereinafter, specific embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments at all and can be implemented with appropriate modifications within the scope of the purpose of the present invention.

[0025] <Polyacetal resin composition>

[0026] The polyacetal resin composition of the present invention is characterized in that it contains, relative to 100 parts by mass of (A) polyacetal resin: (B) 1 part by mass or more and 100 parts by mass or less of glass fiber surface-treated with a blocked isocyanate compound, an aminosilane coupling agent and an epoxy resin; (C) 0.001 parts by mass or more and 2 parts by mass or less of at least one organic metal compound selected from organic metal compounds, wherein the organic metal compound is an organic metal compound having a metal selected from Zn, Sn and Pb; and (D) 0.002 parts by mass or more and 10 parts by mass or less of a triazine derivative having a nitrogen-containing functional group.

[0027] <(A) Polyacetal resin>

[0028] The (A) polyacetal resin of the present invention is a polymer compound with oxymethylene (-CH2O-) as the main structural unit, and can be: a polyoxymethylene homopolymer with only oxymethylene as the structural unit, or a copolymer, dimer, or block polymer with oxymethylene as the main structural unit and a small amount of other structural units, such as structural units derived from comonomers such as ethylene oxide, 1,3-dioxolane, and 1,4-butanediol formal.

[0029] In addition, the polyacetal resin may have not only a linear structure but also a branched or cross-linked structure copolymerized with a comonomer having a glycidyl ether structure, or a known modified polyoxymethylene into which other organic groups are introduced. In addition, the polyacetal resin may be a mixture of a resin having a linear structure and a resin having a branched and / or cross-linked structure.

[0030] The degree of polymerization of the polyacetal resin is not particularly limited as long as it has melt moldability (for example, a melt flow rate (MFR) of 1.0 g / 10 min to 100 g / 10 min at 190° C. and a load of 2160 g according to ISO 1133).

[0031] <(B) Glass fiber surface-treated with a blocked isocyanate compound, an aminosilane coupling agent, and an epoxy resin>

[0032] (B) Glass fibers surface-treated with a blocked isocyanate compound, an aminosilane coupling agent, and an epoxy resin (hereinafter, also referred to as "surface-treated glass fibers") refer to glass fibers surface-treated with a blocked isocyanate compound, an aminosilane coupling agent, and an epoxy resin. The glass fibers only need to be surface-treated with the blocked isocyanate compound, the aminosilane coupling agent, and the epoxy resin, regardless of the order of the surface treatment.

[0033] That is, the surface-treated glass fiber of the present invention may be one that is surface-treated with a blocked isocyanate compound and then surface-treated with an aminosilane coupling agent and an epoxy resin, or one that is surface-treated with an aminosilane coupling agent and then surface-treated with a blocked isocyanate compound and an epoxy resin.

[0034] In addition, the glass fiber may be surface treated with an aminosilane coupling agent and an epoxy resin and then surface treated with a blocked isocyanate compound, or may be surface treated with an aminosilane coupling agent and a blocked isocyanate compound and then surface treated with an epoxy resin. Of course, the glass fiber may also be surface treated with a blocked isocyanate compound, an aminosilane coupling agent, and an epoxy resin simultaneously.

[0035] Furthermore, the surface-treated glass fiber can be surface-treated by adding a polyurethane resin and / or a polyacrylic resin (acrylic homopolymer, acrylic acid / methyl acrylate copolymer, acrylic acid / methyl methacrylate, etc.) and / or a fluorescent brightener to the blocked isocyanate compound, the aminosilane coupling agent and the epoxy resin.

[0036] It should be noted that whether the surface-treated glass fiber is surface-treated with a blocked isocyanate compound, an aminosilane coupling agent, and an epoxy resin can be distinguished by extracting the glass fiber from a polyacetal resin composition solvent and analyzing the extracted components using a known analysis device.

[0037] 《Blocked isocyanate compounds》

[0038] As the isocyanate compound serving as a raw material of the blocked isocyanate compound, any polyfunctional isocyanate compound having two or more isocyanate groups in one molecule can be used without particular limitation.

[0039] Examples of isocyanate compounds include aliphatic, alicyclic (hereinafter also referred to as "alicyclic") and aromatic isocyanate compounds. Among these, from the viewpoint of compatibility and compatibility with the polyacetal resin, bifunctional aliphatic or alicyclic diisocyanate compounds, aromatic diisocyanate compounds, and polyisocyanates obtained by polymerizing these diisocyanate compounds are preferred.

[0040] The aliphatic diisocyanate compound preferably has a carbon number of 4 or more and 30 or less, and more preferably has a carbon number of 5 or more and 10 or less. Examples of such aliphatic diisocyanate compounds include tetramethylene-1,4-diisocyanate, pentamethylene-1,5-diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethyl-hexamethylene-1,6-diisocyanate, lysine diisocyanate, and the like.

[0041] The alicyclic diisocyanate compound preferably has 8 to 18 carbon atoms, and more preferably has 10 to 15 carbon atoms. Examples of such alicyclic diisocyanate compounds include isophorone diisocyanate, 1,3-bis(isocyanatemethyl)-cyclohexane, and 4,4'-dicyclohexylmethane diisocyanate.

[0042] Examples of the aromatic diisocyanate compound include xylylene diisocyanate, toluene diisocyanate, and diphenylmethane diisocyanate.

[0043] Examples of polyisocyanates include: compounds having at least two isocyanate groups per molecule such as toluene diisocyanate or diphenylmethane diisocyanate; aromatic diisocyanate compounds such as meta-xylylene diisocyanate, α,α,α',α'-tetramethyl-meta-xylylene diisocyanate; aralkyl diisocyanate compounds such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate or isophorone diisocyanate; isocyanate group-containing prepolymers obtained by addition reaction of aliphatic or alicyclic diisocyanate compounds with polyols; prepolymers having isocyanurate rings obtained by cyclotrimerization of the above diisocyanate compounds; or polyisocyanates having a biuret structure obtained by reacting the above diisocyanate compounds with water.

[0044] From the viewpoint of the impact resistance, durability and availability of the obtained composition, among the above-mentioned isocyanate compounds, hexamethylene diisocyanate or a polymer of hexamethylene diisocyanate (e.g., dimer, (cyclic) trimer, pentamer, heptamer, nonamer, undecamer, or a mixture thereof, etc.) is preferred. It should be noted that these isocyanate compounds can be used alone or in combination of two or more.

[0045] As the blocked isocyanate compound of the present invention, there can be used, without particular limitation, any isocyanate compound obtained by blocking the reactive group of the above-mentioned isocyanate compound with a known blocking agent in accordance with a known method.

[0046] Examples of the blocking agent include oxime-based blocking agents such as methyl ethyl ketone oxime, acetone oxime, cyclohexanone oxime, acetophenone oxime, and benzophenone oxime; phenol-based blocking agents such as phenol, cresol, propylphenol, butylphenol, and xylenol; alcohol-based blocking agents such as methanol, ethanol, butanol, 2-ethylhexanol, cyclohexanol, and ethylene glycol monoethyl ether; lactam-based blocking agents such as ε-caprolactam; diketone-based blocking agents such as diethyl malonate and acetoacetate; thiol-based blocking agents such as thiophenol; urea-based blocking agents such as thiourea; imidazole-based blocking agents; carbamic acid-based blocking agents; hydrogen sulfite, etc. Among these, lactam-based blocking agents, oxime-based blocking agents, and diketone-based blocking agents are preferred.

[0047] By using a blocked isocyanate compound, the blocking agent dissociates from the isocyanate group when the polyacetal resin is melted. Therefore, the highly reactive isocyanate group can react only during melt kneading with the polyacetal resin and thereafter, thereby effectively advancing the reaction with the polyacetal resin.

[0048] 《Aminosilane coupling agent》

[0049] An aminosilane coupling agent is used for the surface treatment of the glass fiber of the present invention. The aminosilane coupling agent is a compound containing a silicon atom to which an alkoxy group is bonded and a functional group containing a nitrogen atom in one molecule.

[0050] Examples of the aminosilane coupling agent include 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N,N'-bis-〔3-(trimethoxysilyl)propyl〕ethylenediamine, N,N'-bis-〔3-(triethoxysilyl)propyl〕ethylenediamine, N,N'-bis-〔3-(methyldimethoxysilyl)propyl〕ethylenediamine, N,N'-bis-〔3-(trimethoxysilyl)propyl〕hexamethylenediamine, N,N'-bis-〔3-(triethoxysilyl)propyl〕hexamethylenediamine, and the like. In addition, these aminosilane coupling agents may be used alone or in combination of two or more.

[0051] Among these, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane and N-phenyl-3-aminopropyltrimethoxysilane are preferred, and 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane are more preferred.

[0052] These aminosilane coupling agents are likely to produce a synergistic effect in combination with a blocked isocyanate compound, and can improve the adhesion between the polyacetal resin and the glass fiber.

[0053] Epoxy resin

[0054] The epoxy resin of the present invention can use a known epoxy resin. Examples of the above-mentioned epoxy resins include: bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD ​​type epoxy resin, phenol novolac type or cresol novolac type epoxy resin and other novolac type epoxy resins, aliphatic epoxy resins and their hydrogenated or ether modified products, phenoxy resins, glycidyl ester type epoxy resins, glycidylamine type epoxy resins, cycloaliphatic epoxy resins, and carbamate modified epoxy resins. Among these, bisphenol A type epoxy resin and phenol novolac type epoxy resin are preferred from the aspects of the bundling and hot water resistance of glass fibers. It should be noted that the present invention can select one or more epoxy resins from the above-mentioned epoxy resins for use.

[0055] Fiberglass

[0056] The single fiber diameter of the glass fiber used in the present invention is not particularly limited, preferably 8 μm or more and 20 μm or less. If the single fiber diameter of the glass fiber is 8 μm or more, not only the mechanical properties and hot water resistance of the molded product become good, but also the occurrence of fuzzing caused by the deterioration of the bundling of the glass fiber can be reduced, and the reduction in the productivity of the resin composition can be suppressed. In addition, if the single fiber diameter is 20 μm or less, the strength of the resin composition can be improved. It should be noted that in this specification, the single fiber diameter of the glass fiber refers to the average value of the diameters of 25 multifilament cross sections measured according to JIS R 3420.

[0057] The glass fiber is surface treated with a blocked isocyanate compound, an aminosilane coupling agent, and an epoxy resin, and the amount of each compounded is preferably 0.1 to 10 parts by mass, 0.001 to 0.3 parts by mass, and 0.05 to 1 parts by mass, and more preferably 0.3 to 3 parts by mass, 0.01 to 0.2 parts by mass, and 0.05 to 0.8 parts by mass, relative to 100 parts by mass of the glass fiber before treatment. In addition, the mass ratio of the blocked isocyanate compound, the aminosilane coupling agent, and the epoxy resin is preferably 94 to 45: 1 to 15: 5 to 40, and more preferably 92 to 50: 2 to 12: 6 to 38.

[0058] The amount of the glass fiber that has been surface treated is 1 part by mass or more and 100 parts by mass or less, preferably 5 parts by mass or more and 75 parts by mass or less, more preferably 10 parts by mass or more and 60 parts by mass or less, relative to 100 parts by mass of the polyacetal resin. If the amount of the glass fiber that has been surface treated is 1 part by mass or more, the mechanical properties of the visible molded product and the hot water resistance are fully improved, and if the amount of the glass fiber that has been surface treated is 100 parts by mass or less, the molding process becomes easy.

[0059] <(C) Organic metal compound containing a metal selected from Zn, Sn, and Pb>

[0060] The (C) organic metal compound having a metal selected from Zn, Sn, and Pb (hereinafter also referred to as "organic metal compound") of the present invention refers to an organic metal compound having a bond between the above-mentioned metal and carbon, a metal complex having a coordination bond with the above-mentioned metal, a carboxylate of the above-mentioned metal, and a mixture of a carboxylic acid and an inorganic metal compound.

[0061] 《Organometallic compounds with metal-carbon bonds》

[0062] Examples of the organometallic compound having a metal-carbon bond include organic tin compounds such as dibutyltin dilaurate, dibutyltin di(2-ethylhexanoate), dioctyltin dilaurate, dibutyltin diacetate, dimethyltin dimalate, dibutyltin dioxide, and dioctyltin oxide.

[0063] 《Metal complexes having coordination bonds with metals》

[0064] Examples of the metal complex having a coordination bond with a metal include diketone complexes such as acetylacetonate and alkyl acetylacetate of metals such as tin acetylacetonate, lead acetylacetonate, zinc acetylacetonate, zinc acetylacetonate hydrate, zinc bis(2,6-dimethyl-3,5-heptanedione), zinc bis(2,2,6,6-tetramethyl-3,5-heptanedione), zinc bis(5,5-dimethyl-2,4-hexanedione), and zinc bis(ethylacetoacetate).

[0065] Metal carboxylates

[0066] Examples of the carboxylates of the above-mentioned metals include tin carboxylates (tin acetate, tin propionate, tin octanoate, tin neodecanoate, tin laurate, tin myristate, tin palmitate, tin stearate, tin behenate, tin montanate, 12-hydroxytin stearate, tin cyclohexanebutyrate, tin 2-ethylhexanoate, tin oleate, tin octenate, tin naphthenate, tin benzoate, t-butyltin benzoate, tin salicylate, tin naphthenate, tin polyacrylate, tin polymethacrylate, or a mixture of two or more thereof), lead carboxylates (lead acetate, lead acetate trihydrate, lead propionate, lead octanoate, lead neodecanoate, lead laurate, lead myristate, lead palmitate, lead stearate, lead behenate, lead montanate, 12-hydroxytin stearate, tin cyclohexanebutyrate, tin 2-ethylhexanoate, lead oleate, lead octenate, lead naphthenate, tin benzoate, t-butyltin benzoate, tin salicylate, tin naphthenate, tin polyacrylate, tin polymethacrylate, or a mixture of two or more thereof), and lead carboxylates (lead acetate, lead acetate trihydrate, lead propionate, lead octanoate, lead neodecanoate, lead laurate, lead myristate, lead palmitate, lead stearate, lead behenate, lead montanate, 12-hydroxytin stearate, tin cyclohexanebutyrate, tin 2-ethylhexanoate, lead oleate, lead octenate, lead naphthenate, tin

[0063] The invention also includes zinc carboxylate (zinc acetate, zinc acetate dihydrate, zinc propionate, zinc octanoate, zinc neodecanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc behenate, zinc montanate, zinc 12-hydroxystearate, zinc cyclohexanebutyrate, zinc 2-ethylhexanoate, zinc oleate, zinc octenate, zinc naphthenate, zinc benzoate, zinc tert-butylbenzoate, zinc salicylate, zinc glycolate, zinc lactate, zinc oxalate, zinc malonate, zinc succinate, zinc glutarate, zinc adipate, zinc pimelate, zinc suberate, zinc azelaate, zinc sebacate, zinc dodecanedioate, zinc citrate, zinc polyacrylate, zinc polymethacrylate, or a mixture of two or more thereof).

[0067] Furthermore, the metal carboxylate may be a complex of at least one metal selected from tin, lead, and zinc and another metal (for example, a zinc stearate-calcium stearate complex, a zinc stearate-barium stearate complex, etc.).

[0068] 《Mixtures of carboxylic acids and inorganic metal compounds》

[0069] The mixture of carboxylic acid and inorganic metal compound includes: a mixture of carboxylic acid (acetic acid, propionic acid, octyl acid, neodecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, montanic acid, 12-hydroxystearic acid, cyclohexanebutyric acid, 2-ethylhexanoic acid, oleic acid, octenic acid, cycloalkane acid, benzoic acid, tert-butylbenzoic acid, salicylic acid, cycloalkane acid, glycolic acid, lactic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, polyacrylic acid, polymethacrylic acid, etc.) and inorganic metal compound (tin oxide, tin hydroxide, lead oxide, lead hydroxide, zinc oxide, zinc hydroxide, etc.).

[0070] Among these organometallic compounds, metal carboxylates and mixtures of carboxylic acids and inorganic metal compounds are preferred.

[0071] The amount of the organometallic compound of the present invention to be added is 0.001 parts by mass or more and 2 parts by mass or less, and preferably 0.01 to 0.5 parts by mass, based on 100 parts by mass of the polyacetal resin.

[0072] <(D) Triazine derivatives having a nitrogen-containing functional group>

[0073] The polyacetal resin composition of the present invention contains (D) a triazine derivative having a nitrogen-containing functional group.

[0074] Examples of the triazine derivative (D) having a nitrogen-containing functional group used in the present invention (hereinafter also referred to as "triazine derivative") include melamine, N-methylolmelamine, N,N'-dimethylolmelamine, N,N',N"-trimethylolmelamine, N,N,N',N"-tetramethylolmelamine and other methylolmelamines, or mixtures thereof, alkoxymethylmelamine (described in Japanese Unexamined Patent Application No. 55-15764), 5), melamine prepolymers (described in Japanese Patent Publication No. 7-116346), alkoxymethyl derivatives of methylol melamine, benzoguanamine, methylguanamine, guanamine compounds such as 2,4-diamino-6-butyl-s-triazine, N-butyl melamine, N-phenyl melamine, N,N-diphenyl melamine, N,N-diallyl melamine, N,N',N-triphenyl melamine, 2-oxy-4,6-di Amino-s-triazine, 2,4-diamino-6-benzyloxy-s-triazine, 2,4-diamino-6-butoxy-s-triazine, 2,4-diamino-6-cyclohexyl-s-triazine, 2,4-diamino-6-chloro-s-triazine, 2,4-diamino-6-mercapto-s-triazine, 2,4-dioxy-6-amino-s-triazine, 2-oxy-4,6-diamino-s-triazine, 1,1-bis-(3,5-diamino-2,4,6-triazinyl) Methane, 1,2-bis-(3,5-diamino-2,4,6-triazinyl)ethane [also known as (succiguanamine)], 1,3-bis-(3,5)-diamino-2,4,6-triazinyl)propane, 1,4-bis-(3,5-diamino-2,4,6-triazinyl)butane, methylene melamine, ethylene dimelamine, triguanamine, melamine cyanurate, ethylene di (melamine) cyanurate, triguanamine cyanurate, etc.

[0075] These triazine derivatives may be used alone or in combination of two or more thereof. Among these, guanamine compounds such as benzoguanamine and methylguanamine, methylolmelamine, methylolmelamine alkoxymethyl derivatives, and melamine are preferred, and melamine is more preferred.

[0076] In the present invention, the amount of the triazine derivative (D) having a nitrogen-containing functional group is preferably 0.002 to 10 parts by mass, more preferably 0.01 to 2 parts by mass, particularly preferably 0.03 to 1 part by mass, based on 100 parts by mass of the polyacetal resin.

[0077] When the content of the triazine derivative (D) is at least 0.002 parts by mass, the production stability of the polyacetal resin composition can be improved, and when it is at most 10 parts by mass, bleed-out from the polyacetal resin composition can be suppressed.

[0078] The present invention can improve both the hot water resistance and productivity of the polyacetal resin composition by using (B) surface-treated glass fibers, (C) an organic metal compound having a metal selected from Zn, Sn, and Pb, and (D) a triazine derivative having a nitrogen-containing functional group in combination.

[0079] The inventors speculate that the reason why the polyacetal resin composition of the present invention is excellent in hot water resistance and productivity is that the organometallic compound and the triazine derivative exert some favorable influence on the bonding between the surface-treated glass fiber and the molecular chain terminal of the polyacetal resin.

[0080] <Other additives>

[0081] Other glass fibers

[0082] The polyacetal resin composition of the present invention may contain glass fibers surface-treated with a known coupling agent other than the aminosilane coupling agent. The coupling agent is used to improve the wettability and adhesion of the glass fibers to the polyacetal resin. Examples of the coupling agent include silane-based, titanate-based, aluminum-based, chromium-based, zirconium-based, and borane-based coupling agents. Among these, silane-based coupling agents are preferred.

[0083] Examples of the silane coupling agent include vinylalkoxysilane, epoxyalkoxysilane, mercaptoalkoxysilane, allylalkoxysilane, etc. Examples of the vinylalkoxysilane include vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(2-methoxyethoxy)silane, etc.

[0084] Examples of epoxyalkoxysilane include 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-glycidoxypropyltriethoxysilane.

[0085] Examples of the mercaptoalkoxysilane include 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane.

[0086] Examples of the allylalkoxysilane include 3-diallylaminopropyltrimethoxysilane, 3-allylaminopropyltrimethoxysilane, and 3-allylthiopropyltrimethoxysilane.

[0087] Examples of titanate coupling agents include titanium-isopropoxy suberate, tetra-n-butoxytitanium, tetrakis(2-ethylhexyloxy)titanium, etc. These coupling agents may be used alone or in combination of two or more.

[0088] 《Various stabilizers and additives》

[0089] In addition, the polyacetal resin composition of the present invention may contain known inorganic, organic, and metal fiber-shaped, plate-shaped, powdery, and granular fillers other than glass fiber as long as the performance of the target molded product is not significantly reduced. Examples of the above-mentioned fillers include talc, mica, wollastonite, carbon fiber, glass beads, etc.

[0090] Furthermore, various known stabilizers and additives may be blended. Examples of stabilizers include hindered phenol compounds, hindered amine compounds, hydroxides of alkali or alkaline earth metals, inorganic compounds such as boric acid compounds, carboxylates, etc. Examples of additives include general additives for thermoplastic resins such as dyes and pigments, fluorescent brighteners, lubricants, nucleating agents, mold release agents, antistatic agents, surfactants, etc.

[0091] The type of boric acid compound is not particularly limited, and may be orthoboric acid, metaboric acid, tetraboric acid, dehydrate of orthoboric acid, etc. Among these, orthoboric acid is preferred. The amount of boric acid blended is preferably 0.001 parts by mass or more and 1.0 parts by mass or less, more preferably 0.01 parts by mass or more and 0.5 parts by mass or less.

[0092] <Method for producing polyacetal resin composition>

[0093] Examples of the method for producing the polyacetal resin composition include: a method for producing pellets of the polyacetal resin composition by mixing the above-mentioned components (A) to (D) and then melt-kneading them in a single-screw extruder or a twin-screw extruder; a method for temporarily producing pellets (master batches) of different compositions and mixing (diluting) the pellets in a predetermined amount to obtain a molded article; etc. In addition, examples of the above-mentioned production method also include: a method for producing pellets of the polyacetal resin composition and molding the same after impregnating the above-mentioned components (blocked isocyanate compound, aminosilane coupling agent and epoxy resin) into glass fibers (rovings) subjected to a specific surface treatment.

[0094] In the production of the polyacetal resin composition, a method is preferably to pulverize a part or all of the polyacetal resin as a matrix and mix it with other components before extrusion in order to improve the dispersibility of the additives.

[0095] Example

[0096] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples at all.

[0097] <Production of polyacetal resin composition>

[0098] In 100 parts by mass of (A) polyacetal resin, (B) surface-treated glass fiber, (C) organic metal compound and (D) triazine derivative having nitrogen-containing functional group were blended in the amounts shown in Tables 1 and 2, and melt-kneaded in a twin-screw extruder at a barrel temperature of 200° C. to produce pelletized polyacetal resin compositions of Examples and Comparative Examples. It should be noted that the surface-treated glass fiber was added by side feeding. The units of the values ​​in the table are parts by mass.

[0099] [Table 1]

[0100]

[0101] [Table 2]

[0102]

[0103] The components (A) to (D) shown in Tables 1 and 2 are as follows.

[0104] <(A) Polyacetal resin>

[0105] (A-1)

[0106] Polyacetal resin (polyacetal copolymer obtained by copolymerizing 96.7% by mass of trioxane and 3.3% by mass of 1,3-dioxolane (melt flow value (measured at 190° C. and a load of 2160 g in accordance with ISO1133): 45 g / 10 minutes)

[0107] (A-2)

[0108] Polyacetal resin (polyacetal copolymer obtained by copolymerizing 96.7 mass % of trioxane and 3.3 mass % of 1,3-dioxolane (melt flow value (measured in accordance with ISO1133 at 190° C. and a load of 2160 g): 9 g / 10 minutes)

[0109] <(B) Surface-treated glass fiber>

[0110] The glass fiber used was chopped fiber having a single fiber diameter of 10 μm. (B-1) to (B-9) are materials used for surface treatment of the glass fiber.

[0111] (B-1)

[0112] Blocked isocyanate compound of hexamethylene diisocyanate blocked with methyl ethyl ketone oxime: 0.8 parts by mass

[0113] Aminosilane coupling agent: 0.1 parts by mass

[0114] Bisphenol A epoxy resin: 0.1 parts by mass

[0115] (B-2)

[0116] Blocked isocyanate compound of hexamethylene diisocyanate blocked with methyl ethyl ketone oxime: 0.6 parts by mass

[0117] Aminosilane coupling agent: 0.1 parts by mass

[0118] Bisphenol A epoxy resin: 0.1 parts by mass

[0119] (B-3)

[0120] Blocked isocyanate compound of hexamethylene diisocyanate cyclic trimer blocked with methyl ethyl ketone oxime: 1.2 parts by mass

[0121] Aminosilane coupling agent: 0.1 parts by mass

[0122] Bisphenol A epoxy resin: 0.2 parts by mass

[0123] (B-4)

[0124] Blocked isocyanate compound of hexamethylene diisocyanate cyclic trimer blocked with ε-caprolactam: 0.8 parts by mass

[0125] Aminosilane coupling agent: 0.15 parts by mass

[0126] Bisphenol A epoxy resin: 0.15 parts by mass

[0127] (B-5)

[0128] Blocked isocyanate compound of isophorone diisocyanate blocked with methyl ethyl ketone oxime: 1.2 parts by mass

[0129] Aminosilane coupling agent: 0.1 parts by mass

[0130] Phenol novolac type epoxy resin: 0.2 parts by mass

[0131] (B-6)

[0132] Blocked isocyanate of hexamethylene diisocyanate cyclic trimer blocked with methyl ethyl ketone oxime: 0.6 parts by mass

[0133] Blocked isocyanate compound of hexamethylene diisocyanate cyclic trimer blocked with ε-caprolactam: 0.2 parts by mass

[0134] Aminosilane coupling agent: 0.1 parts by mass

[0135] Bisphenol A epoxy resin: 0.1 parts by mass

[0136] (B-7)

[0137] Blocked isocyanate compound of hexamethylene diisocyanate blocked with methyl ethyl ketone oxime: 0.8 parts by mass

[0138] Aminosilane coupling agent: 0.1 parts by mass

[0139] (B-8)

[0140] Blocked isocyanate compound of hexamethylene diisocyanate blocked with methyl ethyl ketone oxime: 0.8 parts by mass

[0141] Bisphenol A epoxy resin: 0.1 parts by mass

[0142] (B-9)

[0143] Aminosilane coupling agent: 0.1 parts by mass

[0144] Bisphenol A epoxy resin: 0.1 parts by mass

[0145] It should be noted that the aminosilane coupling agent described in (B-1) to (B-9) above is 3-aminopropyltriethoxysilane.

[0146] <(C)Organometallic compounds>

[0147] (C-1) Zinc stearate

[0148] (C-2) 12-Hydroxyzinc stearate

[0149] (C-3) Zinc acetate

[0150] (C-4) stearic acid / zinc oxide = 2 / 1 (molar ratio)

[0151] (C-5) Calcium Stearate

[0152] <(D) Triazine derivatives having a nitrogen-containing functional group>

[0153] (D-1) Melamine

[0154] <Physical property evaluation>

[0155] For the pelletized polyacetal resin compositions of Examples and Comparative Examples, test pieces were prepared using an injection molding machine in accordance with ISO 3167. Then, the tensile strength TS (initial TS, unit: MPa) was measured in accordance with ISO 527-1 and 2. The measurement atmosphere was 23° C. and 50% RH. The results are shown in Tables 3 and 4.

[0156] <Hot water resistance evaluation>

[0157] The test piece prepared according to ISO3167 was immersed in an autoclave containing hot water at 120°C for 4 days and then taken out. The tensile strength (TS after hot water immersion, unit: MPa) was measured under the same measurement conditions as the above physical property evaluation. The tensile strength retention rate (TS retention rate) was calculated by taking the initial TS value measured in the above physical property evaluation as 100%. The results are shown in Tables 3 and 4.

[0158] <Productivity Evaluation>

[0159] When the surface-treated glass fibers were side-fed, the fuzzing of the glass fibers near the feed portion was evaluated visually as follows. A and B are practical levels. The results are shown in Tables 3 and 4.

[0160] A: The occurrence of fuzzing was not observed.

[0161] B: The occurrence of fuzz was slightly observed.

[0162] C: The supply amount of glass fiber varies due to the occurrence of fuzz.

[0163] [Table 3]

[0164]

[0165] [Table 4]

[0166]

[0167] As can be seen from the results in Tables 3 and 4, the molded products of the polyacetal resin composition which is blended with (A) 100 parts by mass of a polyacetal resin; (B) 1 part by mass or more and 100 parts by mass or less of glass fiber surface-treated with a blocked isocyanate compound, an aminosilane coupling agent and an epoxy resin; (C) 0.001 part by mass or more and 2 parts by mass or less of at least one organic metal compound selected from organic metal compounds, wherein the organic metal compound is an organic metal compound having a metal selected from Zn, Sn and Pb; and (D) 0.002 parts by mass or more and 10 parts by mass or less of a triazine derivative having a nitrogen-containing functional group also have excellent hot water resistance and excellent productivity.

[0168] Industrial Applicability

[0169] The polyacetal resin composition of the present invention has not only excellent mechanical properties but also high hot water resistance and excellent productivity, and therefore can be widely used as structural materials and mechanism parts for electrical equipment, automobile parts, precision machinery parts, etc., thereby making it possible to contribute to the industry.

Claims

1. A polyacetal resin composition, comprising, relative to 100 parts by mass of (A) polyacetal resin: (B) 1 part by mass or more and 100 parts by mass or less of glass fibers surface-treated with a blocked isocyanate compound, an aminosilane coupling agent, and an epoxy resin; (C) 0.001 parts by mass or more and 2 parts by mass or less of at least one organometallic compound selected from organometallic compounds, wherein: The organometallic compound is an organometallic compound having a metal selected from Zn, Sn, and Pb, and the organometallic compound having a metal selected from Zn, Sn, and Pb is selected from an organometallic compound having a bond between the metal and carbon, a metal complex having a coordination bond with the metal, a carboxylate of the metal, a mixture of a carboxylic acid and an inorganic metal compound, The organic metal compound having a bond between the metal and carbon is selected from dibutyltin dilaurate, dibutyltin di(2-ethylhexanoate), dioctyltin dilaurate, dibutyltin diacetate, dimethyltin dimalate, dibutyltin dioxide, dioctyltin oxide, The metal complex having a coordination bond with the metal is selected from tin acetylacetonate, lead acetylacetonate, zinc acetylacetonate, zinc acetylacetonate hydrate, bis(2,6-dimethyl-3,5-heptanedione)zinc, bis(2,2,6,6-tetramethyl-3,5-heptanedione)zinc, bis(5,5-dimethyl-2,4-hexanedione)zinc, bis(ethyl acetoacetate)zinc, The inorganic metal compound is selected from tin oxide, tin hydroxide, lead oxide, lead hydroxide, zinc oxide, zinc hydroxide; and (D) 0.002 parts by mass or more and 10 parts by mass or less of a triazine derivative having a nitrogen-containing functional group.

2. The polyacetal resin composition according to claim 1, wherein The organometallic compound (C) having a metal selected from the group consisting of Zn, Sn and Pb is a metal carboxylate.

3. The polyacetal resin composition according to claim 1, wherein The organic metal compound (C) having a metal selected from the group consisting of Zn, Sn and Pb is a mixture of a carboxylic acid and an inorganic metal compound.

4. The polyacetal resin composition according to any one of claims 1 to 3, wherein The triazine derivative having a nitrogen-containing functional group (D) is melamine.

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