Polyacetal resin composition, molded article thereof and article

Abstract

The invention relates to a polyacetal resin composition, a molded article thereof, and an article. The purpose of the present invention is to provide a polyacetal resin composition which suppresses a decrease in impact resistance due to a formaldehyde scavenger, and which has little formaldehyde emission and little mold contamination. A polyacetal resin composition containing (A) a polyacetal resin, (B) a thermoplastic polyurethane, (C) a cyclic urea compound having at least one urea unit-NHCONH-as a constituent unit of a ring, and (D) a polyamide resin, with respect to a total of 100 parts by mass of the polyacetal resin (A) and the thermoplastic polyurethane (B), the polyacetal resin composition contains from 50 parts by mass to 95 parts by mass (inclusive) of the polyacetal resin (A), from 5 parts by mass to 50 parts by mass (inclusive) of the thermoplastic polyurethane (B), from 0.05 parts by mass to 0.2 parts by mass (inclusive) of the cyclic urea compound (C), and from 0.1 parts by mass to 5.0 parts by mass (inclusive) of the polyamide resin (D).

Description

Technical Field

[0001] The present invention relates to a polyacetal resin composition, and a molded product and an article thereof. Background Art

[0002] Polyacetal resin is a crystalline resin, and has excellent rigidity, strength, toughness, sliding property and creep property, and is therefore widely used as materials for mechanical parts such as automotive parts, electrical / electronic parts and industrial parts. Particularly for automotive parts, the requirements of VOC performance and color tone characteristics are constantly improving. In addition, along with the miniaturization and lightweight of automotive parts, the requirements for improving impact resistance are also constantly improving. On the other hand, the compatibility of thermoplastic polyurethane and polyacetal resin is relatively good, and impact resistance can be given to polyacetal resin. Thus, the composition comprising polyacetal resin and thermoplastic polyurethane is often used.

[0003] As such a composition, a composition disclosed in the following Patent Document 1 is known. The following Patent Document 1 discloses a polyacetal resin composition, wherein 1 to 120 parts by mass of a thermoplastic polyurethane resin and 0.01 to 5 parts by mass of a formaldehyde scavenger having formaldehyde-reactive nitrogen are blended with respect to 100 parts by mass of the polyacetal resin, the thermoplastic polyurethane resin having a residual isocyanate amount of 0.1% by mass or less, a water content of 3000 ppm by mass or less, and a melt viscosity of 200,000 poise or more at 180°C.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2013-057044 Summary of the invention

[0007] Problems to be solved by the invention

[0008] However, there is room for improvement in the reduction in impact resistance caused by the addition of a formaldehyde scavenger in the composition described in Patent Document 1. In the case of a polyacetal resin to which a formaldehyde scavenger is added, the thermoplastic polyurethane resin is decomposed by the addition of the formaldehyde scavenger, and the impact resistance of the molded article is reduced.

[0009] In addition, mold contamination caused by the accumulation of formaldehyde scavengers on the mold during continuous molding, which are used to suppress the release of formaldehyde from molded products, has also become a problem.

[0010] Therefore, an object of the present invention is to provide a polyacetal resin composition which improves the reduction in impact resistance caused by a formaldehyde scavenger, has a small amount of formaldehyde emission, and has a small amount of mold contamination.

[0011] Means used to solve problems

[0012] The present inventors have conducted intensive studies to solve the above-mentioned problems of the prior art, and as a result, have found that the above-mentioned problems can be solved by the following means, thereby completing the present invention.

[0013] That is, the present invention is as follows.

[0014] [1] A polyacetal resin composition, wherein the polyacetal resin composition comprises:

[0015] (A) Polyacetal resin,

[0016] (B) Thermoplastic polyurethane,

[0017] (C) a cyclic urea compound having at least one urea unit -NHCONH- as a ring constituent unit, and

[0018] (D) polyamide resin,

[0019] With respect to 100 parts by mass of the total of the (A) polyacetal resin and the (B) thermoplastic polyurethane,

[0020] The polyacetal resin composition comprises:

[0021] 50 parts by mass or more and 95 parts by mass or less of the (A) polyacetal resin,

[0022] 5 parts by mass or more and 50 parts by mass or less of the (B) thermoplastic polyurethane,

[0023] 0.05 parts by mass or more and 0.2 parts by mass or less of the (C) cyclic urea compound, and

[0024] 0.1 parts by mass or more and 5.0 parts by mass or less of the (D) polyamide resin.

[0025] [2] The polyacetal resin composition according to [1], wherein the (C) cyclic urea compound is at least one compound selected from the group consisting of cyclic monoureas and cyclic diureas.

[0026] [3] The polyacetal resin composition according to [1] or [2], wherein the (C) cyclic urea compound does not contain a -CONHNH2 group.

[0027] [4] The polyacetal resin composition according to any one of [1] to [3], wherein the (C) cyclic urea compound is at least one compound selected from the group consisting of ethylene urea, hydantoin, and allantoin.

[0028] [5] The polyacetal resin composition according to any one of [1] to [4], wherein the (D) polyamide resin is an amorphous polyamide resin or a polyamide resin having a melting point of 180° C. or less.

[0029] [6] The polyacetal resin composition according to any one of [1] to [5], wherein the (D) polyamide resin is polyamide 6I or a polyamide 6-66-610 copolymer having a melting point of 180° C. or less.

[0030] [7] The polyacetal resin composition according to any one of [1] to [6], wherein the (D) polyamide resin is polyamide 6I.

[0031] [8] The polyacetal resin composition according to any one of [1] to [7], wherein the (D) polyamide resin comprises:

[0032] (Da) an amorphous polyamide resin or a polyamide resin having a melting point of 180°C or less, and

[0033] (Db) a crystalline polyamide resin having a melting point of 250°C or higher,

[0034] With respect to 100 parts by mass of the total of the (A) polyacetal resin and the (B) thermoplastic polyurethane,

[0035] The amount of the (Da) amorphous polyamide resin or the polyamide resin having a melting point of 180° C. or less is 0.20 parts by mass or more and 2.0 parts by mass or less,

[0036] The amount of the crystalline polyamide resin (Db) having a melting point of 250° C. or higher is 0.01 parts by mass or more and 0.10 parts by mass or less,

[0037] The mass ratio (Db) / (Da) of the crystalline polyamide resin (Db) having a melting point of 250° C. or higher to the amorphous polyamide resin (Da) or the polyamide resin having a melting point of 180° C. or lower is 0.02 to 0.10.

[0038] [9] The polyacetal resin composition according to [8], wherein the (Db) crystalline polyamide resin having a melting point of 250° C. or higher is polyamide 66.

[0039]

[10] The polyacetal resin composition according to any one of [1] to [9], wherein the (A) polyacetal resin has a melt flow rate (MFR) of 15 (g / 10 min) or less.

[0040]

[11] The polyacetal resin composition according to any one of [1] to

[10] , wherein the (D) polyamide resin is a polyamide 6-66-610 copolymer.

[0041] The mass ratio of (C) / (D) is in the range of 0.33 or more and 0.60 or less.

[0042]

[12] The polyacetal resin composition according to any one of [1] to

[10] , wherein the (D) polyamide resin is polyamide 6I,

[0043] The mass ratio of (C) / (D) is in the range of 0.20 to 0.70.

[0044]

[13] A molded article, wherein the molded article is a molded article of the polyacetal resin composition according to any one of [1] to

[12] .

[0045]

[14] An article comprising the molded article described in

[13] , wherein the article is selected from a clip, a wiper, a sun visor, a seat belt, a height adjuster and a gear shift handle.

[0046] Effects of the Invention

[0047] According to the present invention, it is possible to provide a polyacetal resin composition which suppresses a decrease in impact resistance due to a formaldehyde scavenger, has a small amount of formaldehyde emission, and has a small amount of mold contamination. DETAILED DESCRIPTION

[0048] Hereinafter, a mode for carrying out the present invention (hereinafter, sometimes referred to as “the present embodiment”) will be described in detail.

[0049] It should be noted that the present invention is not limited to the following embodiments, and can be implemented with various modifications within the scope of the gist of the invention.

[0050] In this specification, two or more embodiments can be arbitrarily combined.

[0051] Unless otherwise specified, the materials, components, compounds, resins, catalysts, and solvents described in the present specification may be used alone or in combination of two or more.

[0052] In this specification, (A) polyacetal resin, (B) thermoplastic polyurethane, (C) cyclic urea compound and (D) polyamide resin may be referred to as (A) component, (B) component, (C) component and (D) component, respectively.

[0053] In the present embodiment, the melt flow rate (MFR) value of the (A) polyacetal resin (component (A)) refers to a value measured in accordance with ISO1133.

[0054] In the present embodiment, "thermoplastic" means having a reversible property of being able to melt by heating below the decomposition temperature, exhibiting plastic flow while in a molten state, and solidifying by cooling. In general, polyurethane resins begin to decompose at 230°C or higher.

[0055] (Polyacetal resin composition)

[0056] The polyacetal resin composition of the present embodiment is the following polyacetal resin composition, and the polyacetal resin composition comprises:

[0057] (A) Polyacetal resin,

[0058] (B) Thermoplastic polyurethane,

[0059] (C) a cyclic urea compound having at least one urea unit -NHCONH- as a ring constituent unit, and

[0060] (D) polyamide resin,

[0061] With respect to 100 parts by mass of the total of the (A) polyacetal resin and the (B) thermoplastic polyurethane,

[0062] The polyacetal resin composition comprises:

[0063] 50 parts by mass or more and 95 parts by mass or less of the (A) polyacetal resin,

[0064] 5 parts by mass or more and 50 parts by mass or less of the (B) thermoplastic polyurethane,

[0065] 0.05 parts by mass or more and 0.2 parts by mass or less of the (C) cyclic urea compound, and

[0066] 0.1 parts by mass or more and 5.0 parts by mass or less of the (D) polyamide resin.

[0067] In the case of the polyacetal resin composition, the decrease in impact resistance due to the formaldehyde scavenger is improved, the amount of formaldehyde emission is small, and mold contamination during continuous molding due to the formaldehyde scavenger is small.

[0068] First, components that can be contained in the polyacetal resin composition of the present embodiment will be described.

[0069] <(A) Polyacetal resin (component A)>

[0070] The polyacetal resin of the present embodiment refers to a polymer having an oxymethylene group in the main chain. As the polyacetal resin, for example, there can be mentioned: a polyacetal copolymer obtained by copolymerizing a formaldehyde monomer or a cyclic oligomer thereof with a cyclic ether or a cyclic formal; a polyacetal copolymer having a branched chain obtained by copolymerizing a formaldehyde monomer or a cyclic oligomer thereof with a monofunctional glycidyl ether; a polyacetal copolymer having a cross-linked structure obtained by copolymerizing a formaldehyde monomer or a cyclic oligomer thereof with a multifunctional glycidyl ether, etc. In addition, for example, polyacetal homopolymers, polyacetal copolymers, compounds having functional groups such as hydroxyl groups at both ends or at one end, etc. described in Japanese Patent Gazette No. 2020-143256 can also be used.

[0071] The content of the comonomer unit in the case where the (A) polyacetal resin (component (A)) in the present embodiment is a polyacetal copolymer is not particularly limited, but when converted to a content relative to 1 mol of the formaldehyde trimer (trioxymethylene), the comonomer unit is preferably 0.01 mol or more, more preferably 0.02 mol or more, further preferably 0.03 mol or more, and is preferably 0.10 mol or less, more preferably 0.07 mol or less, and further preferably 0.05 mol or less.

[0072] As described above, the (A) polyacetal resin may be either a polyacetal homopolymer or a polyacetal copolymer. Among them, a polyacetal copolymer is preferred from the viewpoint of thermal stability.

[0073] The melt flow rate (MFR) value of the component (A) may be appropriately adjusted, for example, to be 0.1 (g / 10 minutes) or more and 100 (g / 10 minutes) or less. In a preferred embodiment, the MFR value of the component (A) is 0.5 (g / 10 minutes) or more, 1.0 (g / 10 minutes) or more, 2.0 (g / 10 minutes) or more, 2.5 (g / 10 minutes) or more, 3.0 (g / 10 minutes) or more, 4.0 (g / 10 minutes) or more, 5.0 (g / 10 minutes) or more, 6.0 (g / 10 minutes) or more, 7.0 (g / 10 minutes) or more, 8.0 (g / 10 minutes) or more, 9.0 (g / 10 minutes) or more, or 10.0 (g / 10 minutes) or more. In another preferred embodiment, the MFR value of the component (A) is 70 (g / 10 minutes) or less, 60 (g / 10 minutes) or less, 50 (g / 10 minutes) or less, 40 (g / 10 minutes) or less, 30 (g / 10 minutes) or less, 20 (g / 10 minutes) or less, 15.0 (g / 10 minutes) or less, 10.0 (g / 10 minutes) or less, 9.0 (g / 10 minutes) or less, 8.0 (g / 10 minutes) or less, 7.0 (g / 10 minutes) or less, 6.0 (g / 10 minutes) or less, 5.0 (g / 10 minutes) or less, or 4.0 (g / 10 minutes) or less. By adjusting the MFR value of the polyacetal resin (A) to 0.1 (g / 10 minutes) or more and 100 (g / 10 minutes) or less, a polyacetal resin having better mechanical strength can be obtained. In addition, by adjusting the MFR value of the (A) polyacetal resin to 1.0 (g / 10 minutes) or more and 4.0 (g / 10 minutes) or less, a polyacetal resin having further excellent mechanical strength can be obtained.

[0074] In addition, the melt flow rate can be measured using MELT INDEXER F-F01 (manufactured by Toyo Seiki Co., Ltd.).

[0075] The content of component (A) (polyacetal resin) is 50 parts by mass or more and 95 parts by mass or less relative to 100 parts by mass of component (A) (polyacetal resin) and component (B) (thermoplastic polyurethane). In a preferred embodiment, the content of component (A) is preferably 60 parts by mass or more, preferably 65 parts by mass or more, preferably 70 parts by mass or more, 75 parts by mass or more, or 80 parts by mass or more relative to 100 parts by mass of component (A) and component (B). In another preferred embodiment, the content of component (A) is preferably 90 parts by mass or less, 85 parts by mass or less, 80 parts by mass or less, 75 parts by mass or less, or 70 parts by mass or less relative to 100 parts by mass of component (A) and component (B). In another preferred embodiment, from the viewpoint of exhibiting excellent rigidity of the engineering resin, the content of the component (A) is 50 parts by mass or more and 95 parts by mass or less, preferably 60 parts by mass or more and 90 parts by mass or less, and further preferably 70 parts by mass or more and 90 parts by mass or less, relative to 100 parts by mass of the total of the components (A) and (B).

[0076] In addition, the number average molecular weight Mn of the component (A) in the present embodiment is not particularly limited, and is, for example, 20000 or more and 100000 or less. In a preferred embodiment, the Mn of the component (A) is 20000 or more, 25000 or more, 30000 or more, 35000 or more, 40000 or more, 45000 or more, 50000 or more, 55000 or more, 60000 or more, 65000 or more, 70000 or more, 75000 or more, 80000 or more, 85000 or more, 90000 or more, or 95000 or more. In another preferred embodiment, Mn of the component (A) is 100,000 or less, 95,000 or less, 90,000 or less, 85,000 or less, 80,000 or less, 75,000 or less, 70,000 or less, 65,000 or less, 60,000 or less, 55,000 or less, 50,000 or less, 45,000 or less, 40,000 or less, 35,000 or less, 30,000 or less, or 25,000 or less.

[0077] The method for producing the component (A) is not particularly limited, and a known method can be adopted. As a method for producing the component (A), for example, the method described in International Publication No. 2020 / 250895 can be used.

[0078] <(B) Thermoplastic polyurethane ((B) component)>

[0079] As the thermoplastic polyurethane, a polyurethane having thermoplasticity is used. Polyurethane can be obtained by reacting a diol with a diisocyanate.

[0080] As said diol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1, 3- butanediol, 1, 4- butanediol etc. are mentioned, for example.

[0081] Examples of the diisocyanate include aromatic diisocyanate, aliphatic diisocyanate, and alicyclic diisocyanate. These can be used alone or in combination of two or more.

[0082] As said aromatic diisocyanate, 1, 4- phenylene diisocyanate, 2, 4- toluene diisocyanate, 2, 6- toluene diisocyanate, 2, 2- methylene diphenylene diisocyanate, naphthalene diisocyanate etc. are mentioned, for example.

[0083] As said aliphatic diisocyanate, hexamethylene diisocyanate etc. are mentioned, for example.

[0084] Examples of the alicyclic diisocyanate include isophorone diisocyanate, 4,4′-methylenebis(cyclohexyl isocyanate), 1,3-bis(isocyanatemethyl)cyclohexane, and 1,4-bis(isocyanatemethyl)cyclohexane.

[0085] The diisocyanate may be, for example, a dimer or trimer of the above-mentioned aromatic diisocyanate, aliphatic diisocyanate and alicyclic diisocyanate (hereinafter sometimes referred to as "isocyanate compound"), a carbodiimide-modified product of these isocyanate compounds, a prepolymer of these isocyanate compounds and a polyol, or a blocked isocyanate compound obtained by blocking these isocyanate compounds with a blocking agent such as phenol, primary alcohol, or caprolactam.

[0086] The content of the (B) thermoplastic polyurethane (component (B)) is 5 parts by mass or more and 50 parts by mass or less relative to 100 parts by mass of the total of the (A) component ((A) polyacetal resin) and the (B) component ((B) thermoplastic polyurethane). From the viewpoint of improving impact resistance, the content of the (B) thermoplastic polyurethane (component (B)) is preferably 10 parts by mass or more, preferably 15 parts by mass or more, and more preferably 20 parts by mass or more relative to 100 parts by mass of the total of the (A) component and the (B) component. In addition, the content of the (B) thermoplastic polyurethane (component (B)) is preferably 45 parts by mass or less, can be 40 parts by mass or less, can be 35 parts by mass or less, and can also be 30 parts by mass or less.

[0087] <(C) Cyclic urea compounds>

[0088] The polyacetal resin composition of the present embodiment contains (C) a cyclic urea compound from the viewpoint of capturing formaldehyde. By containing (C) a cyclic urea compound, a decrease in impact resistance can be improved, and the polyacetal resin composition can be obtained with less mold contamination.

[0089] Here, the "cyclic urea compound" refers to a compound having at least one urea unit -NHCONH- as a constituent unit of a ring. Each of the H atoms bonded to the N atom in the urea unit is unsubstituted.

[0090] The cyclic urea compound may be at least one compound selected from the group consisting of cyclic monoureas (cyclic monourea) and cyclic diureas (cyclic diurea). Cyclic monoureas (cyclic monourea) refer to compounds having one urea group (urea unit -NHCONH-) as a constituent unit of the ring, and cyclic diureas (cyclic diurea) refer to compounds having two urea groups (urea unit -NHCONH-) as constituent units of the ring. In one embodiment, the cyclic urea compound is a cyclic monourea (cyclic monourea).

[0091] The cyclic urea compound is preferably a cyclic monourea, and from the viewpoint of capturing formaldehyde, at least one compound selected from the group consisting of ethylene urea (also called 2-imidazolidinone), hydantoin and allantoin is particularly preferred. From the viewpoint of mold contamination, ethylene urea or hydantoin is more preferred as the cyclic monourea (cyclic monourea).

[0092] When the cyclic urea compound is ethylene urea, the change in impact resistance over time can be suppressed.

[0093] In addition, the above-mentioned cyclic urea compound preferably does not have a -CONHNH2 group.

[0094] The content of component (C) is 0.05 parts by mass or more and 0.20 parts by mass or less relative to 100 parts by mass of the total of components (A) and (B). In a preferred embodiment, the content of component (C) is preferably 0.06 parts by mass or more, preferably 0.07 parts by mass or more, preferably 0.075 parts by mass or more, preferably 0.08 parts by mass or more, preferably 0.10 parts by mass or more, preferably 0.12 parts by mass or more, preferably 0.15 parts by mass or more relative to 100 parts by mass of the total of components (A) and (B). In another preferred embodiment, the content of component (C) is preferably 0.18 parts by mass or less, preferably 0.16 parts by mass or less, preferably 0.15 parts by mass or less, preferably 0.12 parts by mass or less, preferably 0.10 parts by mass or less relative to 100 parts by mass of the total of components (A) and (B). In another preferred embodiment, the content of the component (C) is preferably 0.10 parts by mass or more and 0.15 parts by mass or less relative to 100 parts by mass of the total of the components (A) and (B).

[0095] <(D) Polyamide resin ((D) component)>

[0096] As (D) polyamide resin (component (D)), there is no particular limitation, and known polyamide resins can be used. Polyamide resin is a general term for polymers having an amide bond in the main chain. Polyamide resins are basically obtained by various reactions such as polycondensation of a dibasic acid and a diamine, polycondensation of an aminocarboxylic acid, or ring-opening polymerization of a lactam. Component (D) may be composed of one structural unit or may be composed of two or more structural units. In the case of a copolymerized polyamide resin, the ratio of the structural units, the copolymerization form (e.g., a random copolymer, a block copolymer, a cross-linked polymer), etc. can be arbitrarily selected.

[0097] Specific examples of the polyamide resin include polycaproamide (polyamide 6), polybutylene adipamide (polyamide 46), polyhexamethylene adipamide (polyamide 66), polyhexamethylene sebacamide (polyamide 610), polyhexamethylene dodecanamide (polyamide 612), polyundecanamide (polyamide 11), polydodecanamide (polyamide 12), polytrimethylhexamethylene terephthalamide (polyamide TMHT), polyhexamethylene terephthalamide (polyamide 6T), polyhexamethylene isophthalamide (polyamide 6I), Polydodecanoylbis(4-aminocyclohexyl)methane (polyamide PACM12), polydodecanoylbis(3-methyl-4-aminocyclohexyl)methane (polyamide dimethyl PACM12), polymethylene adipamide (polyamide MXD6), polynonane terephthalamide (polyamide 9T), polydecane terephthalamide (polyamide 10T), polyundecanediamine terephthalamide (polyamide 11T), polyhexahydroundecane terephthalamide (polyamide 11T(H)), dimer acid polyamide, etc. The polyamide resin may also be a copolymer or a mixture of these polyamides such as polyamide 6-66-610 copolymer and polyamide 6T / 6I.

[0098] When the ratio of the amide bond contained in the component (D) is high, the compatibility with the component (C) is good, and the effect of suppressing the emission of formaldehyde gas and the effect of suppressing the deterioration of physical properties can be more significantly obtained.

[0099] When the concentration of amide bonds contained in the (D) polyamide resin of the present embodiment is high, the compatibility with the (C) ethylene urea is good, and the effect of suppressing the release of formaldehyde gas and the effect of suppressing the degradation of physical properties can be more significantly improved.

[0100] The polyamide resin (D) of the present embodiment is preferably an amorphous polyamide resin or a crystalline polyamide resin having a melting point of 180°C or less. More preferably, it is a crystalline polyamide resin having a melting point of 180°C or less. By using such a polyamide resin, the amount of formaldehyde gas released can be further suppressed. In addition, the melting point of the crystalline polyamide resin is, for example, 160°C or more, 165°C or more, 170°C or more, or 175°C or more.

[0101] Amorphous polyamide resin refers to a resin in which no clear melting peak is observed when the temperature is increased at 10°C / min in accordance with JIS K7121 in differential scanning calorimetry (DSC) analysis, and specifically, refers to a resin in which no melting peak of 4 cal / g or more is observed. In addition, the melting point of a crystalline polyamide resin is the melting peak temperature when the temperature is kept at 30°C higher than the end of the melting peak for 10 minutes, cooled at 10°C / min, and then increased at 10°C / min in accordance with JIS K7121.

[0102] As the amorphous polyamide resin or the crystalline polyamide resin having a melting point of 180° C. or less in the present embodiment, polyamide 6I or a polyamide 6-66-610 copolymer having a melting point of 180° C. or less is particularly preferred.

[0103] The (D) polyamide resin of the present embodiment is preferably at least one of polyamide 6, polyamide 610, polyamide 612, polyamide 11, polyamide 12, polyamide TMHT, polyamide 6I, polyamide PACM12, polyamide dimethyl PACM12, polyamide MXD6, polyamide 6-66 copolymer, polyamide 6-66-610 copolymer, and polyamide 6T / 6I copolymer; more preferably at least one of polyamide TMHT, polyamide 6I, polyamide 6-66 copolymer, and polyamide 6-66-610 copolymer; particularly preferably polyamide 6I or polyamide 6-66-610 copolymer.

[0104] The content of the polyamide resin (D) in the present embodiment is 0.1 parts by mass or more, preferably 0.2 parts by mass or more, preferably 0.21 parts by mass or more, and more preferably 0.3 parts by mass or more, relative to 100 parts by mass of the total of the polyacetal resin and the thermoplastic polyurethane. In another preferred embodiment, the content of the component (D) is 5.0 parts by mass or less, preferably 2.1 parts by mass or less, preferably 1.0 parts by mass or less, more preferably 0.6 parts by mass or less, and further preferably 0.5 parts by mass or less, relative to 100 parts by mass of the total of the components (A) and (B). In another preferred embodiment, the content of the component (D) is 0.3 parts by mass or more and 0.5 parts by mass or less, relative to 100 parts by mass of the total of the components (A) and (B).

[0105] In one embodiment of the polyacetal resin composition, the (D) polyamide resin comprises:

[0106] (Da) amorphous polyamide or polyamide having a melting point of 180°C or less, and

[0107] (Db) a crystalline polyamide resin having a melting point of 250°C or higher,

[0108] With respect to 100 parts by mass of the total of the (A) polyacetal resin and the (B) thermoplastic polyurethane,

[0109] The amount of the (Da) amorphous polyamide or polyamide having a melting point of 180° C. or less is 0.20 parts by mass or more and 2.0 parts by mass or less,

[0110] The amount of the crystalline polyamide resin (Db) having a melting point of 250° C. or higher is 0.01 parts by mass or more and 0.10 parts by mass or less,

[0111] The mass ratio (Db) / (Da) of the crystalline polyamide resin (Db) having a melting point of 250° C. or higher to the amorphous polyamide (Da) or the polyamide having a melting point of 180° C. or lower is 0.02 to 0.10.

[0112] In the case of the polyacetal resin composition, changes in impact resistance due to differences in molding conditions can be suppressed, and a molded article with a low formaldehyde emission amount can be obtained.

[0113] <(Da) Amorphous polyamide resin ((Da) component)>

[0114] As the (Da) amorphous polyamide resin ((Da) component), there is no particular limitation, and known amorphous polyamide resins can be used. Amorphous polyamide resin refers to a polymer that does not have a specific melting point and has an amide bond in the main chain. Polyamide resins are basically obtained by various reactions such as polycondensation of a dibasic acid and a diamine, polycondensation of an aminocarboxylic acid, or ring-opening polymerization of a lactam. The (Da) component may be composed of one structural unit or may be composed of two or more structural units. In the case of a copolymerized polyamide resin, the ratio of the structural units, the copolymerization form (e.g., a random copolymer, a block copolymer, a cross-linked polymer), etc. can be arbitrarily selected.

[0115] Specific examples of amorphous polyamide resins include PA12 / MACMI (PA12 / 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, isophthalic acid), PA12 / MACMT (PA12 / 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, terephthalic acid), PAMACM12 (3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, dodecanedioic acid or laurolactam), PAMC12 (PA12, 1,3-bis(aminomethyl)cyclohexane), PA6I (polyamide 6I) (polyhexamethylene isophthalamide), PA6I / 6T, PA6I / 6T / MACMI, etc. These polyamides may be used alone or as a mixture. As the (Da) amorphous polyamide resin of the present embodiment, polyamide 6I (PA6I) is particularly preferred.

[0116] The content of the component (Da) is preferably 0.20 parts by mass or more and 2.0 parts by mass or less relative to 100 parts by mass of the total of the components (A) and (B). In another preferred embodiment, the content of the component (Da) is preferably 0.30 parts by mass or more, and more preferably 0.50 parts by mass or more relative to 100 parts by mass of the total of the components (A) and (B). In another preferred embodiment, the content of the component (Da) is preferably 1.5 parts by mass or less, more preferably 1.0 parts by mass or less, and further preferably 0.70 parts by mass or less relative to 100 parts by mass of the total of the components (A) and (B). In another preferred embodiment, the content of the component (Da) is preferably 0.30 parts by mass or more and 0.7 parts by mass or less, and more preferably 0.50 parts by mass or more and 0.7 parts by mass or less relative to 100 parts by mass of the total of the components (A) and (B).

[0117] In addition, when the ratio of the amide bond contained in the component (Da) is high, the compatibility with the component (C) is good, and the effect of suppressing the release of formaldehyde gas can be more significantly obtained. From the viewpoint of suppressing the release of formaldehyde gas, the ratio of the amide bond of the component (Da) is preferably 5% by mass to 15% by mass, preferably 7% by mass to 15% by mass, and more preferably 9% by mass to 13% by mass in terms of nitrogen content.

[0118] The ratio of the amide bonds of the component (Da) can be determined by measuring the nitrogen content of the polyamide resin. The nitrogen content of the polyamide resin can be determined by oxidatively decomposing the polyamide using a micro-total nitrogen analyzer (TN-2100H, manufactured by Mitsubishi Chemical Analytical Science), allowing the generated nitrogen monoxide to react with ozone, and measuring the chemiluminescence intensity.

[0119] The number average molecular weight Mn of the (Da) component is preferably 5000 or more and 15000 or less. In one embodiment, the Mn of the (Da) component is 5000 or more, 6000 or more, 7000 or more, 8000 or more, 9000 or more, 10000 or more, 11000 or more, 12000 or more, 13000 or more, or 14000 or more. In another embodiment, the Mn of the (Da) component is 15000 or less, 14000 or less, 13000 or less, 12000 or less, 11000 or less, 10000 or less, 9000 or less, 8000 or less, 7000 or less, or 6000 or less. The number average molecular weight can be measured by gel permeation chromatography (GPC).

[0120] <(Db) Crystalline polyamide resin having a melting point of 250°C or higher>

[0121] The crystalline polyamide resin (Db) of the present embodiment having a melting point of 250°C or more is not particularly limited, and a known crystalline polyamide resin having a melting point of 250°C or more can be used. Crystalline polyamide resin refers to a polymer having a specific melting point and having an amide bond in the main chain. Polyamide resins are basically obtained by various reactions such as polycondensation of dibasic acids and diamines, polycondensation of aminocarboxylic acids, or ring-opening polymerization of lactams. The (Db) component may be composed of one structural unit or of two or more structural units. In the case of a copolymerized polyamide resin, the ratio of the structural units, the copolymerization form (e.g., a random copolymer, a block copolymer, a cross-linked polymer), etc. can be arbitrarily selected.

[0122] Since the polyacetal resin composition of the present embodiment contains the crystalline polyamide resin having a melting point of 250° C. or higher, the crystalline polyamide resin functions as a crystal nucleating agent during molding, and the crystallinity of the molded article can be controlled.

[0123] The melting point of the component (Db) is 250° C. or higher, and more preferably 260° C. or higher. The melting point of the component (Db) is, for example, 320° C. or lower or 300° C. or lower.

[0124] Examples of the component (Db) include PA46 (polyamide 46) (polybutylene adipamide), PA66 (polyamide 66) (polyhexamethylene adipamide), PA6 / 6T (polycaproamide / polyhexamethylene terephthalamide copolymer), PA9T (polynonamethylene terephthalamide), PA10T (polydecamethylene terephthalamide), and PA4T (polybutylene terephthalamide), and these components may be used alone or as a mixture. Among these, the crystalline polyamide resin (Db) of the present embodiment is more preferably at least one of polyamide 66, polyamide 46, polyamide 6 / 6T, and polyamide 4T, and polyamide 66 is particularly preferred.

[0125] As the polyamide resin (D) of the present embodiment, when the components (Da) and (Db) are used in combination, the content of the component (Db) is preferably 0.01 parts by mass or more and 0.10 parts by mass or less relative to 100 parts by mass of the total of the components (A) and (B). In another preferred embodiment, the content of the component (Db) is preferably 0.02 parts by mass or more relative to 100 parts by mass of the total of the components (A) and (B). In another preferred embodiment, the content of the component (Db) is preferably 0.08 parts by mass or less, more preferably 0.06 parts by mass or less, and even more preferably 0.05 parts by mass or less relative to 100 parts by mass of the total of the components (A) and (B). In another preferred embodiment, the content of the component (Db) is 0.02 parts by mass or more and 0.05 parts by mass or less relative to 100 parts by mass of the total of the components (A) and (B).

[0126] When the (Da) component and the (Db) component are used in combination, the mass ratio (Db) / (Da) of the (Db) component to the (Da) component is preferably 0.02 or more and 0.10 or less. In addition, the mass ratio (Db) / (Da) of (Db) to (Da) is preferably 0.025 or more, more preferably 0.027 or more, and most preferably 0.029 or more. On the other hand, the mass ratio (Db) / (Da) of (Db) to (Da) is preferably 0.080 or less, more preferably 0.070 or less, and most preferably 0.050 or less. In another preferred embodiment, from the viewpoint of being able to further suppress the change in impact resistance caused by the difference in molding conditions and being able to further suppress the formaldehyde emission, the mass ratio (Db) / (Da) of (Db) to (Da) is preferably 0.025 or more and 0.100 or less, and more preferably 0.029 or more and 0.070 or less.

[0127] The weight average molecular weight Mw of the component (Db) is preferably 5000 or more and 15000 or less. In one embodiment, the Mw of the component (Db) is 5000 or more, 6000 or more, 7000 or more, 8000 or more, 9000 or more, 10000 or more, 11000 or more, 12000 or more, 13000 or more, or 14000 or more. In another embodiment, the Mw of the component (Db) is 15000 or less, 14000 or less, 13000 or less, 12000 or less, 11000 or less, 10000 or less, 9000 or less, 8000 or less, 7000 or less, or 6000 or less. The weight average molecular weight can be measured by gel permeation chromatography (GPC).

[0128] In the resin composition of the present embodiment, the preferred mass ratio of the (C) cyclic urea compound to the (D) polyamide resin, that is, the mass ratio of the (C) cyclic urea compound / (D) polyamide resin ((C) / (D)) is preferably 0.05 or more, more preferably 0.10 or more, further preferably 0.20 or more, further preferably 0.30 or more, and most preferably 0.32 or more. On the other hand, the mass ratio of the (C) cyclic urea compound / (D) polyamide resin is preferably 2.0 or less, more preferably 1.5 or less, further preferably 1.0 or less, further preferably 0.70 or less, and most preferably 0.6 or less.

[0129] It should be noted that the preferred mass ratio of (C) cyclic urea compound / (D) polyamide resin varies depending on the type of (D) polyamide resin used. When polyamide 6-66-610 copolymer is used as (D) polyamide resin, the mass ratio is preferably 0.33 or more and 0.60 or less, more preferably 0.33 or more and 0.55 or less, and further preferably 0.40 or more and 0.50 or less. In addition, when polyamide 6I is used as (D) polyamide resin, the mass ratio is preferably 0.20 or more and 0.70 or less, more preferably 0.25 or more and 0.60 or less, and further preferably 0.30 or more and 0.50 or less.

[0130] <(E) Other ingredients ((E) ingredients)>

[0131] The polyacetal resin composition may contain, in addition to the components (A) to (D), other components, for example, a formaldehyde scavenger other than the cyclic urea compound (C), an antioxidant, a formic acid scavenger, a weather stabilizer, a mold release agent, a lubricant, a conductive agent, a dye / pigment, or a well-known additive such as an inorganic filler or an organic filler (E) other component (component (E)).

[0132] The content of (E) other components may be appropriately adjusted. For example, the content of (E) other components is preferably 50 parts by mass or less, preferably 30 parts by mass or less, preferably 10 parts by mass or less, preferably 5 parts by mass or less, or preferably 1 part by mass or less, relative to 100 parts by mass of the total of the components (A) and (B).

[0133] As a formaldehyde scavenger other than the cyclic urea compound (C), a basic nitrogen compound other than the cyclic urea compound (C) can be used. Examples of basic nitrogen compounds other than the cyclic urea compound (C) include aminotriazine compounds, guanidine compounds, amino acid compounds, amino alcohol compounds, imide compounds, and amide compounds described in Japanese Patent Application Laid-Open No. 2005-163019. In one embodiment, the polyacetal resin composition does not contain a formaldehyde scavenger other than the cyclic urea compound (C).

[0134] (Method for producing polyacetal resin composition)

[0135] The polyacetal resin composition is not particularly limited, and can be produced by, for example, kneading the component (A), the component (B), the component (C), the component (D), and other components as necessary.

[0136] The kneading machine is not particularly limited, and a known kneading machine can be used. For example, the kneading machine described in International Publication No. 2020 / 250895 can be mentioned.

[0137] From the viewpoint of thermal stability and productivity, it is preferred to use an extruder equipped with a venting and decompression device for mixing. In addition, in order to manufacture the polyacetal resin composition in large quantities and stably, it is preferred to use a single screw or twin screw extruder. When a single screw or twin screw extruder is used, a granulated polyacetal resin composition (hereinafter sometimes referred to as "polyacetal resin granules") can be obtained.

[0138] Alternatively, the components may be continuously supplied to the extruder alone or in combination using a quantitative feeder or the like without mixing them in advance.

[0139] Alternatively, a high-concentration masterbatch containing each component may be prepared in advance and diluted with the polyacetal resin during extrusion melt kneading.

[0140] The kneading temperature may be determined according to the preferred processing temperature of the polyacetal resin used, and is usually set in the range of 140°C to 260°C, preferably in the range of 160°C to 230°C.

[0141] (Molded article of polyacetal resin composition)

[0142] The polyacetal resin composition of the present embodiment can be molded and used as a molded article.

[0143] The molding method of the polyacetal resin composition is not particularly limited, and a known molding method of the polyacetal resin composition can be used. For example, a molding method such as injection molding described in International Publication No. 2020 / 250895 can be mentioned.

[0144] The molded article of the present embodiment is preferably a molded article using the polyacetal resin composition of the present embodiment.

[0145] <Application of molded products>

[0146] The molded product of this embodiment has excellent quality stability and can be used for various purposes, such as mechanism parts (e.g., gears, cams, sliders, rods, shafts, bearings, guides, etc.), resin parts for injection molding on substrates, resin parts for insert molding (chassis, trays, side panel parts), printer parts, copier parts, digital camera equipment parts, digital video equipment parts, music equipment parts, imaging equipment parts, information equipment parts, communication equipment parts, electrical equipment parts, and electronic equipment parts.

[0147] In addition, the molded article of this embodiment is suitable for interior parts, door peripheral parts, seat belt peripheral parts, combination switch parts, and switches as automobile parts. Examples of interior parts, door peripheral parts, seat belt peripheral parts, combination switch parts, and switches include: inner handles, fuel tank openers, seat belt buckles, auxiliary handles, various switches, knobs, rods, clips, etc. In addition, the molded article of this embodiment can also be suitably used as industrial parts represented by residential equipment machines.

[0148] The article of this embodiment preferably includes the molded article of this embodiment.

[0149] In one embodiment, the article of this embodiment preferably comprises the molded article of this embodiment, and the article is preferably selected from a clip, a wiper, a sun visor, a seat belt, a height adjuster and a gear shift handle.

[0150] Example

[0151] Hereinafter, the present embodiment will be described with reference to Examples and Comparative Examples, but the present embodiment is not limited to the following Examples.

[0152] The measurement and evaluation methods used in Examples and Comparative Examples are as follows.

[0153] <Evaluation of Mechanical Properties (Impact Resistance)>

[0154] The test piece was produced using EC100SX manufactured by Toshiba Machine Co., Ltd. under the conditions of barrel temperature: 205° C., injection time: 35 seconds, cooling time: 15 seconds, and mold temperature: 80° C., and an ISO dumbbell test piece for property evaluation was molded. This molding condition is referred to as molding condition I.

[0155] Then, the following test was performed on the test piece.

[0156] The Charpy impact strength was evaluated based on ISO179 / 1eA on the day after molding and 30 days later. The evaluation results are shown in Tables 1 and 2 below.

[0157] In addition, the Charpy impact strength of each Example and each Comparative Example was evaluated as a Charpy impact strength improvement rate relative to the Charpy impact strength of the reference examples (Reference Examples 1 to 11) having the same ratio of the (A) component to the (B) component. The Charpy impact strength improvement rate is preferably improved by 10% or more, and more preferably improved by 15% or more, compared to the samples of the reference examples having the same ratio of the (A) component to the (B) component.

[0158] In addition, in order to evaluate the change in impact resistance caused by molding conditions, EC100SX manufactured by Toshiba Machine Co., Ltd. was used to prepare test pieces under the conditions of barrel temperature: 220°C, injection time: 35 seconds, cooling time: 15 seconds, and mold temperature: 80°C, and ISO dumbbell test pieces for physical property evaluation were molded. This molding condition was referred to as molding condition II.

[0159] For these test pieces, impact resistance was evaluated based on Charpy impact strength: ISO179 / 1eA on the day after molding.

[0160] As an index of the change in impact resistance of the molded product caused by the molding conditions, the ratio of the Charpy impact value of the molded product under molding condition I to the Charpy impact value of the molded product under molding condition II (Charpy impact value (molding condition II] / Charpy impact value (molding condition I)) is used as an index. The closer the value of Charpy impact value (molding condition II] / Charpy impact value (molding condition I) is to 1.0, the smaller the change in impact resistance caused by the difference in molding conditions is, that is, the change in impact resistance caused by the difference in molding conditions can be suppressed. Specifically, the Charpy impact value [molding condition II] / Charpy impact value (molding condition I) is preferably 0.80 or more, and more preferably 0.85 or more.

[0161] <Evaluation of the amount of formaldehyde gas from molded products>

[0162] [Preparation of Flat Plate Test Specimens]

[0163] Test pieces were prepared using an IS-100GN injection molding machine manufactured by Toshiba Machine Co., Ltd., with the barrel temperature set to 200°C, injection time set to 15 seconds, cooling time set to 20 seconds, and mold temperature set to 77°C. The amount of formaldehyde released from the molded product was measured using the VDA275 method (under the following conditions).

[0164] [VDA275 method]

[0165] The amount of formaldehyde generated from the test piece was measured in accordance with VDA275 as follows. First, 50 mL of distilled water and the prepared test piece were placed in a polyethylene container and sealed. Next, the polyethylene container was heated at 60°C for 3 hours, and then the formaldehyde generated in the distilled water was reacted with acetylacetone in the presence of ammonium ions. The obtained reaction product was used as the object, and the absorption peak at a wavelength of 412 nm was measured using a UV spectrometer to determine the amount of formaldehyde generated per 1 kg of the test piece (mg / kg). The smaller the value of the formaldehyde emission, the better. The value of the formaldehyde emission is preferably less than 2.0 mg / kg, and more preferably less than 1.5 mg / kg.

[0166] <Mold contamination>

[0167] Using the product name "Si-30V" manufactured by Toyo Machine Metal Co., Ltd., under the conditions of mold setting temperature: 60 °C, barrel temperature: 200 °C, injection pressure: 34 MPa, injection time: 20 seconds, and cooling time: 15 seconds, the mold fouling on the mold surface after 1000 consecutive injections into an arrow-shaped mold with a test piece of 30 mm × 12 mm × 2 mm was confirmed. The presence or absence of mold fouling was observed from a direction perpendicular to the surface on the fixed side of the mold and evaluated according to the following evaluation criteria. Evaluation A is qualified, and evaluations B and C are unqualified.

[0168] A: No mold fouling was observed at all.

[0169] B: Colorless mold fouling was observed.

[0170] C: An interference color (interference fringes) of mold fouling with a thickness estimated to be 200 nm or more was generated.

[0171] [Raw material components]

[0172] The raw material components used in the examples and comparative examples are as follows.

[0173] <(A) Polyoxymethylene resin>

[0174] (A-1) Polyoxymethylene copolymer (MFR: 2.5 g / 10 min): (Trade name: TENAC-C 3510, manufactured by Asahi Kasei)

[0175] (A-2) Polyoxymethylene copolymer (MFR: 9.0 g / 10 min): (Trade name: TENAC-C 4520, manufactured by Asahi Kasei)

[0176] (A-3) Polyoxymethylene homopolymer (MFR: 5.0 g / 10 min): (Obtained by anionic polymerization of formaldehyde in the presence of a catalyst)

[0177] <(B) Polyurethane resin>

[0178] (B-1) Polyurethane elastomer (Trade name: WHT-1180K, manufactured by Wanhua Chemical Co., Ltd.)

[0179] (B-2) Polyurethane elastomer (Trade name: WHT-1185F, manufactured by Wanhua Chemical Co., Ltd.)

[0180] <Component C>

[0181] (C-1) Hydantoin (manufactured by Tokyo Chemical Industry)

[0182] (C-2) Allantoin (manufactured by Tokyo Chemical Industry)

[0183] (C-3) Ethyleneurea (manufactured by Tokyo Chemical Industry)

[0184] <(D) Polyamide resin>

[0185] (D-1) Polyamide 6-66-610 (melting point 175°C): obtained by copolymerizing ε-caprolactam, adipic acid and hexamethylenediamine. Equivalent to (Da) a crystalline polyamide resin having a melting point of 180°C or less.

[0186] (D-2) Polyamide 6I (number average molecular weight Mn=9760) (amorphous): obtained by copolymerizing isophthalic acid and hexamethylenediamine. Corresponding to (Da) amorphous polyamide.

[0187] (D-3) Polyamide 66 (weight average molecular weight Mw=10,000, melting point 260°C): obtained by polymerizing adipic acid and hexamethylenediamine. Corresponding to (Db) a crystalline polyamide having a melting point of 250°C or higher.

[0188] <Other ingredients>

[0189] (E-1) Benzoguanamine (manufactured by Tokyo Chemical Industry)

[0190] (E-2) Adipic acid dihydrazide (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0191] (E-3) Dodecanedioic acid dihydrazide (manufactured by Tokyo Chemical Industry)

[0192] (E-4) Amicure VDH (manufactured by Ajinomoto Fine-Techno)

[0193] The above-mentioned (E-1) to (E-4) are formaldehyde scavengers other than the (C) cyclic urea compound.

[0194] (Production of polyacetal resin composition and molded article thereof)

[0195] According to the ratios shown in Tables 1 and 2, a twin-screw extruder (TEM-26SS extruder manufactured by Toshiba Machine Co., Ltd. (L / D=48, with exhaust port) was used, the barrel temperature was all set to 200°C, and the (A) to (E) components were supplied from the main feed port of the extruder by a quantitative feeder. The resin kneaded product was extruded into a strand shape under the conditions of an extrusion rate of 20 kg / hour and a screw speed of 200 rpm, and was quenched in a strand bath and cut with a strand cutter to obtain pellets of the resin composition of each example, reference example and comparative example. Using each of the obtained resin compositions, molded articles of each example, reference example and comparative example were produced by the above-mentioned measurement / evaluation methods, and various physical properties were evaluated.

[0196] Tables 1 to 6 show the blending amounts, evaluation results, and the like.

[0197] [Table 1]

[0198]

[0199] [Table 2]

[0200]

[0201] [Table 3]

[0202]

[0203] [Table 4]

[0204]

[0205] [Table 5]

[0206]

[0207] [Table 6]

[0208]

[0209] As shown in the table, it can be seen that the polyacetal resin compositions obtained in Examples have improved Charpy impact strength, less formaldehyde emission, and less mold contamination than those in Reference Examples.

[0210] Industrial Applicability

[0211] According to the present invention, it is possible to provide a polyacetal resin composition which suppresses a decrease in impact resistance due to a formaldehyde scavenger, has a small amount of formaldehyde emission, and has a small amount of mold contamination.

[0212] One embodiment of the present invention is as follows.

[0213] [1] A polyacetal resin composition, wherein the polyacetal resin composition comprises:

[0214] (A) Polyacetal resin,

[0215] (B) Thermoplastic polyurethane,

[0216] (C) Cyclic urea compounds, and

[0217] (D) polyamide resin,

[0218] With respect to 100 parts by mass of the total of the (A) polyacetal resin and the (B) thermoplastic polyurethane,

[0219] The polyacetal resin composition comprises:

[0220] 50 parts by mass or more and 95 parts by mass or less of the (A) polyacetal resin,

[0221] 5 parts by mass or more and 50 parts by mass or less of the (B) thermoplastic polyurethane,

[0222] 0.05 parts by mass or more and 0.2 parts by mass or less of the (C) cyclic urea compound, and

[0223] 0.1 part by mass or more and 1.0 part by mass or less of the (D) polyamide resin.

[0224] [2] The polyacetal resin composition according to [1], wherein the (D) polyamide resin is an amorphous polyamide or a polyamide having a melting point of 180° C. or less.

[0225] [3] The polyacetal resin composition according to [1] or [2], wherein the (D) polyamide resin is polyamide 6I or a polyamide 6-66-610 copolymer having a melting point of 180° C. or less.

[0226] [4] The polyacetal resin composition according to any one of [1] to [3], wherein the (D) polyamide resin is polyamide 6I.

[0227] [5] The polyacetal resin composition according to any one of [1] to [4], wherein the (A) polyacetal resin has a melt flow rate (MFR) of 4 (g / 10 min) or less.

[0228] [6] The polyacetal resin composition according to any one of [1] to [5], wherein the (D) polyamide resin is a polyamide 6-66-610 copolymer.

[0229] The mass ratio of (C) / (D) is in the range of 0.33 or more and 0.60 or less.

[0230] [7] The polyacetal resin composition according to any one of [1] to [6], wherein the (D) polyamide resin is polyamide 6I,

[0231] The mass ratio of (C) / (D) is in the range of 0.20 or more and 0.70 or less.

[0232] [8] A molded article, wherein the molded article is a molded article of the polyacetal resin composition according to any one of [1] to [7].

Claims

1. A polyacetal resin composition, wherein The polyacetal resin composition comprises: (A) Polyacetal resin, (B) Thermoplastic polyurethane, (C) a cyclic urea compound having at least one urea unit -NHCONH- as a ring constituent unit, and (D) polyamide resin, With respect to 100 parts by mass of the total of the (A) polyacetal resin and the (B) thermoplastic polyurethane, The polyacetal resin composition comprises: 50 parts by mass or more and 95 parts by mass or less of the (A) polyacetal resin, 5 parts by mass or more and 50 parts by mass or less of the (B) thermoplastic polyurethane, 0.05 parts by mass or more and 0.2 parts by mass or less of the (C) cyclic urea compound, and 0.1 parts by mass or more and 5.0 parts by mass or less of the (D) polyamide resin.

2. The polyacetal resin composition according to claim 1, wherein The (C) cyclic urea compound is at least one compound selected from the group consisting of cyclic monoureas and cyclic diureas.

3. The polyacetal resin composition according to claim 1, wherein The (C) cyclic urea compound does not contain a -CONHNH2 group.

4. The polyacetal resin composition according to claim 1, wherein The (C) cyclic urea compound is at least one compound selected from the group consisting of ethylene urea, hydantoin and allantoin.

5. The polyacetal resin composition according to claim 1, wherein The (D) polyamide resin is an amorphous polyamide resin or a polyamide resin having a melting point of 180° C. or less.

6. The polyacetal resin composition according to claim 1, wherein The (D) polyamide resin is polyamide 6I or a polyamide 6-66-610 copolymer having a melting point of 180° C. or less.

7. The polyacetal resin composition according to claim 1, wherein The (D) polyamide resin is polyamide 6I.

8. The polyacetal resin composition according to claim 1, wherein The (D) polyamide resin comprises: (Da) an amorphous polyamide resin or a polyamide resin having a melting point of 180°C or less, and (Db) a crystalline polyamide resin having a melting point of 250°C or higher, With respect to 100 parts by mass of the total of the (A) polyacetal resin and the (B) thermoplastic polyurethane, The amount of the (Da) amorphous polyamide resin or the polyamide resin having a melting point of 180° C. or less is 0.20 parts by mass or more and 2.0 parts by mass or less, The amount of the crystalline polyamide resin (Db) having a melting point of 250° C. or higher is 0.01 parts by mass or more and 0.10 parts by mass or less, The mass ratio (Db) / (Da) of the crystalline polyamide resin (Db) having a melting point of 250° C. or higher to the amorphous polyamide resin (Da) or the polyamide resin having a melting point of 180° C. or lower is 0.02 to 0.

10.

9. The polyacetal resin composition according to claim 8, wherein The (Db) crystalline polyamide resin having a melting point of 250° C. or higher is polyamide 66.

10. The polyacetal resin composition according to claim 1, wherein The (A) polyacetal resin has a melt flow rate (MFR) of 15 (g / 10 minutes) or less.

11. The polyacetal resin composition according to claim 1, wherein The (D) polyamide resin is a polyamide 6-66-610 copolymer, The mass ratio of (C) / (D) is in the range of 0.33 or more and 0.60 or less.

12. The polyacetal resin composition according to claim 1, wherein The (D) polyamide resin is polyamide 6I, The mass ratio of (C) / (D) is in the range of 0.20 or more and 0.70 or less.

13. A molded article, wherein The molded article is a molded article of the polyacetal resin composition according to any one of claims 1 to 12.

14. An article comprising the molded article according to claim 13, wherein: The items are selected from the group consisting of clips, wipers, sun visors, seat belts, height adjusters and gear shift handles.

Images