WO2022270184A1 - Polyacetal resin composition and gear formed of resin - Google Patents

Polyacetal resin composition and gear formed of resin Download PDF

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Publication number
WO2022270184A1
WO2022270184A1 PCT/JP2022/020764 JP2022020764W WO2022270184A1 WO 2022270184 A1 WO2022270184 A1 WO 2022270184A1 JP 2022020764 W JP2022020764 W JP 2022020764W WO 2022270184 A1 WO2022270184 A1 WO 2022270184A1
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mass
parts
less
component
polyacetal
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PCT/JP2022/020764
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French (fr)
Japanese (ja)
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裕基 神田
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ポリプラスチックス株式会社
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G2/00—Addition polymers of aldehydes or cyclic oligomers thereof or of ketones; Addition copolymers thereof with less than 50 molar percent of other substances
    • C08G2/18—Copolymerisation of aldehydes or ketones
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K13/00—Use of mixtures of ingredients not covered by one single of the preceding main groups, each of these compounds being essential
    • C08K13/04—Ingredients characterised by their shape and organic or inorganic ingredients
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/24—Acids; Salts thereof
    • C08K3/26—Carbonates; Bicarbonates
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/01—Hydrocarbons
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/04—Oxygen-containing compounds
    • C08K5/10—Esters; Ether-esters
    • C08K5/101—Esters; Ether-esters of monocarboxylic acids
    • C08K5/103—Esters; Ether-esters of monocarboxylic acids with polyalcohols
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L13/00—Compositions of rubbers containing carboxyl groups
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/26—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers modified by chemical after-treatment
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L59/00—Compositions of polyacetals; Compositions of derivatives of polyacetals
    • C08L59/04—Copolyoxymethylenes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L71/00—Compositions of polyethers obtained by reactions forming an ether link in the main chain; Compositions of derivatives of such polymers
    • C08L71/02—Polyalkylene oxides
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
    • F16H55/02—Toothed members; Worms
    • F16H55/06—Use of materials; Use of treatments of toothed members or worms to affect their intrinsic material properties

Definitions

  • the present invention relates to a polyacetal resin composition and a resin gear.
  • Polyacetal resin also called polyoxymethylene resin, abbreviated as POM resin
  • POM resin polyoxymethylene resin
  • the properties required in this field are gradually becoming more sophisticated, and as one example, there is a demand for further improvements in sliding properties as well as general physical properties.
  • Such sliding properties are anti-friction and wear properties, and in order to further improve such properties, POM resin compositions containing various additives have been proposed (see Patent Document 1).
  • Patent Document 2 Although the POM resin composition described in Patent Document 2 is excellent in sliding properties under specific environments as described above, it is used for applications that require high levels of durability and mechanical properties, such as materials for gears. Considering this, there is still room for further improvement.
  • the present invention has been made in view of the conventional problems described above, and an object of the present invention is to provide a polyacetal resin composition and a resin gear which are excellent in durability, mechanical properties, and sliding properties.
  • A contains oxymethylene units as main constituents, and contains 0.4 mol % or more and 0.9 mol % or less of oxyalkylene units other than oxymethylene units as comonomer units, and melts For 100 parts by mass of a linear polyacetal copolymer having a flow rate of 1 to 12 g/10 minutes, (B) (b1) trioxane, (b2) a compound having 3 or more and 4 or less cyclic ether units in one molecule, and (b3) a copolymer of a compound having one cyclic ether unit in one molecule, branched or 1 part by mass or more and 10 parts by mass or less of a polyacetal copolymer having a crosslinked structure; (C) 0.5 parts by mass or more and 10 parts by mass or less of a modified olefin polymer obtained by modifying an olefin polymer with at least one selected from unsaturated carboxylic acids,
  • the POM resin composition of the present embodiment has (A) oxymethylene units as main constituents, and the ratio of oxyalkylene units other than oxymethylene units as comonomer units to all constituent units is 0.4 mol % or more and 0.9.
  • the following components (B) to (G) are contained with respect to 100 parts by mass of a linear polyacetal copolymer containing mol % or less and having a melt flow rate (MFR) of 1 to 12 g/10 minutes.
  • (B) (b1) trioxane, (b2) a compound having 3 or more and 4 or less cyclic ether units in one molecule, and (b3) a copolymer of a compound having one cyclic ether unit in one molecule, branched or 1 part by mass or more and 10 parts by mass or less of a polyacetal copolymer having a crosslinked structure.
  • (C) 0.5 parts by mass or more and 10 parts by mass or less of a modified olefin polymer obtained by modifying an olefin polymer with at least one selected from unsaturated carboxylic acids, unsaturated fatty acid anhydrides, and derivatives thereof; .
  • an oxyalkylene unit when an oxyalkylene unit is described, it means an oxyalkylene unit other than an oxymethylene unit.
  • the linear polyacetal copolymer (A) which is the base resin, has a low MFR (that is, a high molecular weight) and a low content of oxyalkylene units as comonomer units;
  • a linear polyacetal copolymer and (B) a polyacetal copolymer having a branched or crosslinked structure are combined to improve durability.
  • the use of a linear polyacetal copolymer provides sufficient mechanical properties
  • the addition of (B) a polyacetal copolymer having a branched or crosslinked structure further improves the mechanical properties.
  • by adding predetermined amounts of components (C) to (G) to 100 parts by mass of the polyacetal copolymer (A), the sliding properties are improved.
  • Each component will be described in detail below.
  • a linear polyacetal copolymer (A) (also referred to as “(A) component” in this specification) is used as the base resin.
  • the component (A) according to the present embodiment has oxymethylene units ( --CH.sub.2O--) as main structural units, and the ratio of oxyalkylene units to all structural units is 0.4 mol % or more and 0.9 mol % or less. contains. By using such component (A), mechanical properties can be improved.
  • Trioxane is widely used as the main raw material for component (A).
  • Trioxane is a cyclic trimer of formaldehyde, and is generally obtained by reacting an aqueous formaldehyde solution in the presence of an acidic catalyst, and is used after being purified by a method such as distillation.
  • Trioxane preferably contains as little impurities as water, methanol, and formic acid.
  • the oxyalkylene unit is contained in an amount of 0.4 mol% or more and 0.9 mol% or less as a proportion of all structural units. becomes insufficient, and if it exceeds 0.9 mol %, the mechanical properties (tensile strength) deteriorate.
  • the ratio of the oxyalkylene units to all structural units is preferably 0.5 mol % or more and 0.8 mol % or less, and more preferably 0.5 mol % or more and 0.7 mol % or less.
  • Examples of oxyalkylene units include an oxyethylene group, an oxypropylene group, an oxybutylene group, and the like.
  • the number of carbon atoms in the oxyalkylene unit is not particularly limited, it is more preferably 2 or more and 4 or less.
  • Examples of comonomers from which oxyalkylene units are derived include one or more compounds selected from monofunctional cyclic ether compounds and monofunctional cyclic formal compounds.
  • the monofunctional cyclic ether compound refers to a compound having one cyclic ether unit per molecule
  • the monofunctional cyclic formal compound refers to a compound having one cyclic formal unit per molecule. .
  • Component (A) has a melt flow rate (MFR) of 1 to 12 g/10 minutes at 190° C. under a load of 2160 g in order to improve creep resistance.
  • MFR melt flow rate
  • the melt flow rate is preferably 1.2 to 10 g/10 minutes, more preferably 1.5 g/10 minutes or more and less than 7 g/10 minutes.
  • the melt flow rate is a numerical value measured according to ISO 1133.
  • (A) component can be produced by a known production method.
  • a polyacetal copolymer having a branched or crosslinked structure includes (b1) trioxane, (b2) a compound having 3 or more and 4 or less cyclic ether units in one molecule, and (b3) a cyclic ether unit in one molecule. is a copolymer with a compound having one
  • the (B) polyacetal copolymer having a branched or crosslinked structure is also referred to as "(B) component".
  • Trioxane is the same as the trioxane described for component (A), and is a cyclic trimer of formaldehyde. (b1) Trioxane is also preferably free of impurities as much as possible.
  • (b2) a compound having 3 or more and 4 or less cyclic ether units in one molecule
  • a compound having 3 to 4 cyclic ether units in one molecule means an epoxy unit, a glycidyl unit, a 1,3-dioxolane unit, a 1,4-butanediol formal unit, and a diethylene glycol formal unit in one molecule. and 1,3,6-trioxepane units. If the number of cyclic ether units is 2, there is a possibility that sufficient rigidity cannot be obtained. Specifically, the flexural modulus of a test piece conforming to ISO178 may be less than 2700 MPa. On the other hand, if the number of cyclic ether units is too large, toughness may decrease.
  • the cyclic ether unit is preferably a glycidyl unit
  • preferred compounds include triglycidyl ether compounds and tetraglycidyl ether compounds. Examples thereof include glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether and the like. These compounds can be used alone or in combination of two or more for copolymerization with (a) trioxane.
  • the copolymerization amount of the compound having 3 or more and 4 or less cyclic ether units in one molecule is not particularly limited.
  • the polymerization amount is preferably 0.01 parts by mass or more and 1 part by mass or less, more preferably 0.05 parts by mass or more and 0.5 parts by mass or less with respect to 100 parts by mass of trioxane (b1). 0.1 part by mass or more and 0.3 part by mass or less is more preferable.
  • (b3) a compound having one cyclic ether unit in one molecule (b3) A compound having one cyclic ether unit in one molecule is suitable for stabilizing the polymerization reaction during the production of component (B) and increasing the thermal stability of the component (B) produced. is.
  • Compounds having one cyclic ether unit in one molecule include ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, epibromohydrin, styrene oxide, oxetane, 3,3-bis(chloromethyl)oxetane , tetrahydrofuran, trioxepane, 1,3-dioxolane, ethylene glycol formal, propylene glycol formal, diethylene glycol formal, triethylene glycol formal, 1,4-butanediol formal, 1,5-pentanediol formal, 1,6-hexanediol formal etc.
  • ethylene oxide, 1,3-dioxolane, 1,4-butanediol formal, and diethylene glycol formal are preferred.
  • the amount of the compound (b3) having one cyclic ether unit in one molecule in the component (B) is not particularly limited, it should be 20 parts by mass or less with respect to 100 parts by mass of the (b1) trioxane. , more preferably 0.05 to 15 parts by mass, and even more preferably 0.1 to 10 parts by mass.
  • the modified olefin polymer is also referred to as "(C) component".
  • the sliding properties are excellent.
  • the polyacetal resin composition contains an olefinic polymer other than the component (C)
  • the sliding properties are poor.
  • the olefin polymer (before modification) used in component (C) includes homopolymers of ⁇ -olefins such as ethylene, propylene, butene, hexene, octene, nonene, decene, and dodecene, and two or more of these. Random, block or graft copolymers, and non-conjugated diene components such as 1,4-hexadiene, dicyclopentadiene, 5-ethylidene-2-norbornene, 2,5-norbornadiene, butadiene, isoprene, piperylene, etc.
  • Conjugated diene components ⁇ , ⁇ -unsaturated acids such as acrylic acid and methacrylic acid, derivatives such as esters thereof, aromatic vinyl compounds such as acrylonitrile, styrene, ⁇ -methylstyrene, vinyl esters such as vinyl acetate, and vinyl methyl
  • aromatic vinyl compounds such as acrylonitrile, styrene, ⁇ -methylstyrene, vinyl esters such as vinyl acetate, and vinyl methyl
  • vinyl esters such as vinyl acetate, and vinyl methyl
  • vinyl methyl examples include random, block or graft copolymers containing at least one comonomer component such as vinyl ethers such as ethers and derivatives of these vinyl compounds, and the degree of polymerization, the presence or absence of side chains and branches, and the like. It does not matter what the degree, copolymer composition ratio, etc. are.
  • olefin polymers examples include high pressure polyethylene, medium and low pressure polyethylene, gas phase ethylene- ⁇ -olefin copolymer, LLDPE, polypropylene, polybutene, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer. polymers, ethylene-ethyl acrylate copolymers, ethylene-butyl acrylate copolymers, ethylene-propylene copolymers, ethylene-propylene-diene terpolymers, and the like. Preferred are polyethylene, ethylene-methyl acrylate copolymer and ethylene-ethyl acrylate copolymer.
  • the component (C) used in the present embodiment includes the above olefin-based polymer, acrylic acid, methacrylic acid, maleic acid, citraconic acid, itaconic acid, tetrahydrophthalic acid, nadic acid, methylnadic acid, and allylsuccinic acid. and unsaturated carboxylic anhydrides such as maleic anhydride, citraconic anhydride, itaconic anhydride, tetrahydrophthalic anhydride, nadic anhydride, methyl nadic anhydride, allyl succinic anhydride, and these It is modified with at least one selected from the group consisting of derivatives and the like.
  • Component (C) preferably has a melt flow rate (MFR) of 0.01 to 100 g/10 minutes, more preferably 0.1 to 50 g/10 minutes, and particularly preferably. are those with an MFR of 0.2 to 30 g/10 min.
  • MFR melt flow rate
  • the melt flow rate (MFR) is a numerical value measured in accordance with ISO 1133.
  • preferable component (C) examples include polyethylene modified with maleic anhydride, polypropylene, ethylene-propylene copolymer, ethylene-ethyl acrylate copolymer, and the like. Among them, it is preferable that the component (C) contains polyethylene modified with maleic anhydride, because the sliding properties of the molded product obtained by molding the polyacetal resin composition are enhanced.
  • an olefin polymer and at least one compound selected from the group consisting of unsaturated carboxylic acids, anhydrides thereof, and derivatives thereof are added in a solution state or a molten state.
  • a method of heating and reacting in the presence of a radical initiator such as an appropriate organic peroxide under certain conditions is suitable, but the method is not particularly limited to this.
  • the blending amount of both components is suitably 0.1 to 20 parts by mass, preferably 0.1 to 10 parts by mass, per 100 parts by mass of the olefinic polymer. If the effective amount of the compound in the olefinic polymer modified with such a compound is too low, the affinity between components (A) and (C) may be insufficient; In this case, physical properties to be improved such as sliding properties may be deteriorated.
  • component (C) is preferably contained in an amount of 0.5 parts by mass or more and 10 parts by mass or less, and may be contained in an amount of 2 parts by mass or more and 7 parts by mass or less with respect to 100 parts by mass of component (A). more preferred. If the amount of component (C) is less than 0.5 parts by mass in the obtained polyacetal resin composition, the amount of frictional wear may increase, which is not preferable. If the amount of component (C) is more than 10 parts by mass, mechanical properties may deteriorate, which is not preferable.
  • the alkylene glycol-based polymer is also referred to as "(D) component".
  • the sliding properties are excellent.
  • Component (D) is an alkylene glycol-based polymer having a primary amino group or a secondary amino group, which is a homopolymer or copolymer of ethylene glycol, propylene glycol, or tetramethylene glycol, at the terminal or in the molecular chain.
  • the type of polymer is not particularly limited, but if the alkylene glycol polymer is a slightly modified polymer such as forming an ester with a fatty acid or an ether with an aliphatic alcohol, the polyacetal resin composition It is preferable in that the sliding property of a molded product obtained by molding an object is enhanced.
  • the number average molecular weight of component (D) is from 400 to 500,000, preferably from 400 to 100,000, and more preferably from 1,000 to 6,000. This is because the dispersibility of component (C) in the polyacetal resin is improved by blending component (D), but if the number average molecular weight of component (D) is less than 400, component (A) or component (C) This is because if the number average molecular weight exceeds 500,000, the melt viscosity becomes high and it becomes difficult to disperse it in the polyacetal resin.
  • the blending amount of component (D) is 0.01 parts by mass or more and 5 parts by mass or less, more preferably 0.1 parts by mass or more and 4 parts by mass or less, relative to component (A), and 0.3 parts by mass. It is more preferably 1 part or more and 3 parts by mass or less, and particularly preferably 1 part or more and 2 parts by mass or less. Above all, when the amount of the component (D) is 1 part by mass or more, it is preferable in that the sliding properties of a molded product obtained by molding the polyacetal resin composition can be greatly improved. If the amount of component (D) is less than 0.01 parts by mass, the effect of improving the sliding properties of the molded product cannot be sufficiently obtained, and if it exceeds 5 parts by mass, the mechanical properties are unfavorably lowered.
  • the above (E) spindle-shaped calcium carbonate is also referred to as "(E) component".
  • the component (E) blended in the linear polyacetal resin (A) is particles belonging to light calcium carbonate and having a spindle shape.
  • the spindle shape refers to a shape similar to a spindle used for spinning yarn, that is, a cylindrical shape with a thick central portion and gradually tapered ends.
  • the barrel-shaped calcium carbonate may have a shape generally similar to this.
  • the average particle diameter is preferably 0.1 to 1 ⁇ m, the average particle length is 0.5 to 10 ⁇ m, and the average value of particle length/particle diameter is preferably 2 to 10, more preferably 3 to 6.
  • the particle diameter refers to the diameter of the spindle-shaped particle at its maximum diameter (usually, approximately the center in the longitudinal direction), and the particle length refers to the length of the spindle-shaped particle.
  • the average particle diameter and average particle length are obtained by photographing spindle-shaped calcium carbonate with an electron microscope, reading the particle diameter and particle length of 50 particles randomly selected from the photograph, and calculating the average value. It refers to the value measured by the method.
  • Examples of such a specific (E) component include Silver W, PC, PCX, and Callite SA manufactured by Shiraishi Kogyo Co., Ltd.
  • Component (E) used in the present embodiment is preferably surface-treated with a surface treating agent, particularly preferably aminosilane.
  • SL-101 manufactured by Shiraishi Kogyo Co., Ltd. is exemplified as the component (E) that has undergone such a surface treatment.
  • the blending amount of component (E) is 0.1 to 20 parts by mass, more preferably 0.1 to 1 part by mass, relative to component (A). If the amount of component (E) is less than 0.1 parts by mass, frictional wear may increase, and if it exceeds 20 parts by mass, the surface properties may deteriorate, which is not preferable.
  • the partial ester of the polyhydric alcohol is also referred to as "(F) component".
  • the surface properties and sliding properties are excellent.
  • a lubricant as a component of a polyacetal resin composition.
  • both the partial ester as the (F) component and the alpha olefin oligomer as the (G) component described later are essential constituent elements. Even if a lubricant other than these components (F) and (G) is contained as a lubricant, it cannot be said that the surface properties are as excellent as in the present embodiment, and thus it is not preferable.
  • the component (F) examples include glycerin monostearate, glycerin distearate, glycerin monobehenate, pentaerythritol monostearate, and the like.
  • the partial ester as the component (F), if the ester is not a partial ester, it is not preferable in that the molded article obtained by molding the polyacetal resin composition has poor surface properties and sliding properties.
  • the blending amount of component (F) is 0.1 parts by mass or more and 10 parts by mass or less, more preferably 0.5 parts by mass or more and 2 parts by mass or less relative to component (A). If the amount of component (F) is less than 0.1 parts by mass, frictional wear may increase, and if it exceeds 10 parts by mass, bleeding may occur, which is not preferable.
  • the oligomer is also referred to as "(G) component".
  • the sliding properties are excellent.
  • the blending amount of component (G) is 0.1 parts by mass or more and 10 parts by mass or less, more preferably 1 part by mass or more and 5 parts by mass or less relative to component (A). If the amount of component (G) is less than 0.1 part by mass, the molded product obtained by molding the polyacetal resin composition may have poor sliding properties. It is not preferable because it may
  • the stability of the polyacetal resin composition according to the present embodiment can be enhanced by further adding various known stabilizers. Moreover, in order to improve the physical properties according to the intended use, various known additives may be added.
  • Additives include various colorants, mold release agents, nucleating agents, antistatic agents, other surfactants, heterogeneous polymers (other than the above-mentioned graft copolymer), and the like.
  • fibrous, powdery, granular, plate-like fillers such as inorganic, organic, and metal are used alone or in combination. You can also
  • the polyacetal resin composition according to the present embodiment can be easily prepared by a known method generally used as a conventional resin composition preparation method. For example, (1) a method of mixing all the components that make up the composition, feeding this to an extruder and melt-kneading to obtain a pellet-like composition, (2) a method of obtaining a pellet-like composition, A method of obtaining a composition in the form of pellets by supplying the remaining components from the main feed port of the extruder and melt-kneading them from the side feed port. It is also possible to adopt a method of adjusting the composition to a predetermined composition.
  • the resin gear of this embodiment is formed by molding the polyacetal resin composition described above. As with the polyacetal resin composition of the present embodiment, the resin gear of the present embodiment is excellent in durability, mechanical properties, and sliding properties.
  • the method for molding a resin gear using the polyacetal resin composition according to this embodiment is not particularly limited, and various methods known in the technical field can be employed.
  • the polyacetal resin composition according to the present embodiment is put into an extruder, melt-kneaded and pelletized, and the pellets are put into an injection molding machine equipped with a predetermined mold and injection molded. can be done.
  • the resin gear of this embodiment can be formed by molding the polyacetal resin composition according to this embodiment into a plate-like or rod-like shape, and then molding them by general molding such as cutting.
  • gears to which the resin gear of the present embodiment can be applied are not particularly limited. Gears, straight bevel gears, spiral bevel gears, zerol bevel gears, screw gears, cylindrical worm gears, and the like.
  • a continuous twin-screw polymerization machine was used as a polymerization reactor. This polymerization machine is equipped with a jacket for passing a medium for heating or cooling on the outside, and two rotating shafts with many paddles for stirring and propelling are provided in the longitudinal direction inside. ing. A heat medium of 80° C. is passed through the jacket of the twin-screw polymerizer, and while the two rotating shafts are rotated at a constant speed, 10.0 kg/hr of trioxane and 0 of 1,3-dioxolane as a comonomer are added to one end of the shaft.
  • Linear Polyacetal Copolymer A-3 A linear polyacetal copolymer A-3 was obtained in the same manner as the linear polyacetal copolymer A-1. However, the amount of 1,3-dioxolane was 0.19 kg/hr.
  • Linear Polyacetal Copolymer A-5 A linear polyacetal copolymer A-5 was obtained in the same manner as the linear polyacetal copolymer A-1. However, the amount of 1,3-dioxolane was 0.29 kg/hr.
  • melt flow rate (MFR) The melt flow rate (MFR) of the linear polyacetal copolymers A-1 to A-6 obtained as described above was measured according to ISO 1133. Table 1 shows the measurement results.
  • a polyacetal copolymer B-2 was obtained in the same manner as the linear polyacetal copolymer A-1.
  • pentaerythritol tetraglycidyl ether (PETGE) (tetrafunctional) 10 g/hr as the first comonomer (b2) and 1,3-dioxolane as the second comonomer (b3) 0.11 Kg/hr was used and the amount of methylal was 4.0 g/hr.
  • C Modified olefin polymer
  • C-1 Maleic anhydride-modified low-density polyethylene (LDPE) (product name: Toughmer MM6850, manufactured by Mitsui Chemicals, Inc.)
  • C-2) Maleic anhydride-modified ethylene-ethyl acrylate copolymer (EEA) (product name: HPR AR2011, manufactured by DuPont Mitsui Polychemicals Co., Ltd.)
  • D Alkylene glycol polymer having a primary amino group or secondary amino group and a number average molecular weight of 400 or more and 500,000 or less
  • D-1) Amine-modified polyethylene glycol (PEG) at both ends (product name : Chemistat Y-400, number average molecular weight: 4,000, manufactured by Sanyo Chemical Industries Co., Ltd.)
  • E) Spindle-shaped calcium carbonate (E-1) Spindle-shaped calcium carbonate (product name: SL-101, average particle size: 0.3 ⁇ m
  • Creep resistance (creep rupture time) An ISO Type-A test piece with a thickness of 4 mm was molded, and a creep test was performed using a creep tester under an environment of 80 ° C. under a load of 20 MPa, and the time until rupture (creep rupture time (h) ) were compared. Three samples were measured, and the average value was taken as the creep rupture time.
  • Comparative Example 1 in which the proportion of oxyethylene units in component (A) was excessive, was inferior in creep resistance and mechanical strength.
  • Comparative Example 2 in which the component (A) had an excessively high MFR, was inferior in creep resistance.
  • Comparative Example 3 in which the compound (b2) having 3 to 4 cyclic ether units per molecule was not used as the component (B), was inferior in creep resistance and mechanical strength.
  • Comparative Examples 4 and 6, in which the content of component (B) was too small or did not contain component (B), were inferior in creep resistance and mechanical strength.
  • Comparative Example 5 in which the content of component (B) was excessive, was inferior in creep resistance.
  • Comparative Example 7, which did not contain components (B) to (G) was inferior in quietness. That is, Comparative Example 7 was inferior in sliding properties.

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Abstract

A polyacetal resin composition which contains, per 100 parts by mass of (A) a linear polyacetal copolymer that has a specific MFR and is mainly composed of an oxymethylene unit, while containing an oxyalkylene unit that serves as a comonomer unit at a predetermined ratio, 1 to 10 parts by mass of (B) a specific polyacetal copolymer that has a branched or crosslinked structure, 0.5 to 10 parts by mass of (C) a specific modified olefin polymer, 0.01 to 5 parts by mass of (D) a specific alkylene glycol polymer, 0.1 to 20 parts by mass of (E) a specific calcium carbonate, 0.1 to 10 parts by mass of a partial ester of a polyhydric alcohol having a functionality of 2 to 4, and 0.1 to 10 parts by mass of (G) an alpha olefin oligomer.

Description

ポリアセタール樹脂組成物及び樹脂製歯車Polyacetal resin composition and resin gear
　本発明は、ポリアセタール樹脂組成物及び樹脂製歯車に関する。 The present invention relates to a polyacetal resin composition and a resin gear.
　ポリアセタール樹脂（ポリオキシメチレン樹脂とも称され、ＰＯＭ樹脂と略される。）は、バランスのとれた機械的性質を有し、耐摩擦・摩耗特性、耐薬品性、耐熱性、電気特性等に優れるため、自動車、電気・電子製品等の分野で広く利用されている。かかる分野における要求特性は次第に高度化しつつあり、その一例として、一般物性と共に摺動特性の一層の向上が望まれている。かかる摺動特性とは、耐摩擦・摩耗特性であり、そのような特性の更なる向上を図るため、種々の添加剤を添加したＰＯＭ樹脂組成物が提案されている（特許文献１参照）。 Polyacetal resin (also called polyoxymethylene resin, abbreviated as POM resin) has well-balanced mechanical properties and is excellent in friction/wear resistance, chemical resistance, heat resistance, electrical properties, etc. Therefore, it is widely used in fields such as automobiles and electric/electronic products. The properties required in this field are gradually becoming more sophisticated, and as one example, there is a demand for further improvements in sliding properties as well as general physical properties. Such sliding properties are anti-friction and wear properties, and in order to further improve such properties, POM resin compositions containing various additives have been proposed (see Patent Document 1).
　一方、砂などのダスト及び水分が存在する環境下においては、部材同士が擦れ合うと、いわゆる鳴き音（squeak noise）といった異音が発生したり、摩耗量が多くなったりするといった問題がある。そのため、ダスト及び水分が存在する環境下における摺動特性は、平常時と同じように考えることができない。そこで、本出願人は、そのような環境下において、耐摩擦摩耗性に優れ、摺動時において異音の発生が極めて少なく、かつ、優れた機械特性（引張強度）を有する、ＰＯＭ樹脂組成物からなる耐ダスト摺動性部材を提案した（特許文献２参照）。 On the other hand, in an environment where dust such as sand and moisture exist, there is a problem that when the members rub against each other, an abnormal noise such as so-called squeak noise is generated and the amount of wear increases. Therefore, the sliding properties in an environment where dust and moisture are present cannot be considered the same as in normal times. Therefore, the present applicant has developed a POM resin composition that has excellent friction and wear resistance, generates very little abnormal noise during sliding, and has excellent mechanical properties (tensile strength) under such an environment. proposed a dust-sliding resistant member consisting of (see Patent Document 2).
特許５８４７２６１号公報Japanese Patent No. 5847261 国際公開第２０１９／０６５４６５号WO2019/065465
　しかしながら、特許文献２に記載のＰＯＭ樹脂組成物は、上記のような特定環境下における摺動特性には優れるものの、耐久性及び機械特性が高いレベルで要求される用途、例えば歯車の材料とすることを考えた場合には更なる改善の余地が残されていた。 However, although the POM resin composition described in Patent Document 2 is excellent in sliding properties under specific environments as described above, it is used for applications that require high levels of durability and mechanical properties, such as materials for gears. Considering this, there is still room for further improvement.
　本発明は、上記従来の問題点に鑑みなされたものであり、その課題は、耐久性、機械特性、及び摺動特性に優れるポリアセタール樹脂組成物及び樹脂製歯車を提供することにある。 The present invention has been made in view of the conventional problems described above, and an object of the present invention is to provide a polyacetal resin composition and a resin gear which are excellent in durability, mechanical properties, and sliding properties.
　前記課題を解決する本発明の一態様は以下の通りである。
　（１）（Ａ）オキシメチレン単位を主たる構成成分とし、コモノマー単位としてオキシメチレン単位以外のオキシアルキレン単位を全構成単位に占める割合として０．４モル％以上０．９モル％以下含有し、メルトフローレートが１～１２ｇ／１０分である線状ポリアセタール共重合体１００質量部に対し、
　（Ｂ）（ｂ１）トリオキサン、（ｂ２）１分子中に環状エーテル単位を３以上４以下有する化合物及び（ｂ３）１分子中に環状エーテル単位を１個有する化合物の共重合体である、分岐又は架橋構造を有するポリアセタール共重合体１質量部以上１０質量部以下と、
　（Ｃ）不飽和カルボン酸、不飽和脂肪酸の酸無水物及びこれらの誘導体から選択される少なくとも１種によってオレフィン系重合体が変性された変性オレフィン系重合体０．５質量部以上１０質量部以下と、
　（Ｄ）１級アミノ基又は２級アミノ基を有し、数平均分子量が４００以上５００，０００以下であるアルキレングリコール系重合体０．０１質量部以上５質量部以下と、
　（Ｅ）紡錘状炭酸カルシウム０．１質量部以上２０質量部以下と、
　（Ｆ）２価以上４価以下の多価アルコールの部分エステル０．１質量部以上１０質量部以下と、
　（Ｇ）アルファオレフィンオリゴマー０．１質量部以上１０質量部以下と、
　を含有する、ポリアセタール樹脂組成物。 One aspect of the present invention for solving the above problems is as follows.
(1) (A) contains oxymethylene units as main constituents, and contains 0.4 mol % or more and 0.9 mol % or less of oxyalkylene units other than oxymethylene units as comonomer units, and melts For 100 parts by mass of a linear polyacetal copolymer having a flow rate of 1 to 12 g/10 minutes,
(B) (b1) trioxane, (b2) a compound having 3 or more and 4 or less cyclic ether units in one molecule, and (b3) a copolymer of a compound having one cyclic ether unit in one molecule, branched or 1 part by mass or more and 10 parts by mass or less of a polyacetal copolymer having a crosslinked structure;
(C) 0.5 parts by mass or more and 10 parts by mass or less of a modified olefin polymer obtained by modifying an olefin polymer with at least one selected from unsaturated carboxylic acids, unsaturated fatty acid anhydrides, and derivatives thereof; When,
(D) 0.01 parts by mass or more and 5 parts by mass or less of an alkylene glycol polymer having a primary amino group or a secondary amino group and a number average molecular weight of 400 or more and 500,000 or less;
(E) 0.1 parts by mass or more and 20 parts by mass or less of spindle-shaped calcium carbonate;
(F) 0.1 parts by mass or more and 10 parts by mass or less of a partial ester of a polyhydric alcohol having a valence of 2 or more and 4 or less;
(G) an alpha olefin oligomer of 0.1 parts by mass or more and 10 parts by mass or less;
A polyacetal resin composition containing
（２）前記（１）に記載のポリアセタール樹脂組成物を成形してなる樹脂製歯車。 (2) A resin gear formed by molding the polyacetal resin composition according to (1) above.
　本発明によれば、耐久性、機械特性、及び摺動特性に優れるポリアセタール樹脂組成物及び樹脂製歯車を提供することができる。 According to the present invention, it is possible to provide a polyacetal resin composition and a resin gear that are excellent in durability, mechanical properties, and sliding properties.
＜ポリアセタール樹脂組成物＞
　本実施形態のＰＯＭ樹脂組成物は、（Ａ）オキシメチレン単位を主たる構成成分とし、コモノマー単位としてオキシメチレン単位以外のオキシアルキレン単位を全構成単位に占める割合として０．４モル％以上０．９モル％以下含有し、メルトフローレート（ＭＦＲ）が１～１２ｇ／１０分である線状ポリアセタール共重合体１００質量部に対し、以下の（Ｂ）～（Ｇ）成分を含有する。
　（Ｂ）（ｂ１）トリオキサン、（ｂ２）１分子中に環状エーテル単位を３以上４以下有する化合物及び（ｂ３）１分子中に環状エーテル単位を１個有する化合物の共重合体である、分岐又は架橋構造を有するポリアセタール共重合体１質量部以上１０質量部以下。
　（Ｃ）不飽和カルボン酸、不飽和脂肪酸の酸無水物及びこれらの誘導体から選択される少なくとも１種によってオレフィン系重合体が変性された変性オレフィン系重合体０．５質量部以上１０質量部以下。
　（Ｄ）１級アミノ基又は２級アミノ基を有し、数平均分子量が４００以上５００，０００以下であるアルキレングリコール系重合体０．０１質量部以上５質量部以下。
　（Ｅ）紡錘状炭酸カルシウム０．１質量部以上２０質量部以下。
　（Ｆ）２価以上４価以下の多価アルコールの部分エステル０．１質量部以上１０質量部以下。
　（Ｇ）アルファオレフィンオリゴマー０．１質量部以上１０質量部以下。
　以下において、オキシアルキレン単位と表記した場合、オキシメチレン単位以外のオキシアルキレン単位を示す。 <Polyacetal resin composition>
The POM resin composition of the present embodiment has (A) oxymethylene units as main constituents, and the ratio of oxyalkylene units other than oxymethylene units as comonomer units to all constituent units is 0.4 mol % or more and 0.9. The following components (B) to (G) are contained with respect to 100 parts by mass of a linear polyacetal copolymer containing mol % or less and having a melt flow rate (MFR) of 1 to 12 g/10 minutes.
(B) (b1) trioxane, (b2) a compound having 3 or more and 4 or less cyclic ether units in one molecule, and (b3) a copolymer of a compound having one cyclic ether unit in one molecule, branched or 1 part by mass or more and 10 parts by mass or less of a polyacetal copolymer having a crosslinked structure.
(C) 0.5 parts by mass or more and 10 parts by mass or less of a modified olefin polymer obtained by modifying an olefin polymer with at least one selected from unsaturated carboxylic acids, unsaturated fatty acid anhydrides, and derivatives thereof; .
(D) 0.01 parts by mass or more and 5 parts by mass or less of an alkylene glycol polymer having a primary amino group or secondary amino group and a number average molecular weight of 400 or more and 500,000 or less;
(E) 0.1 parts by mass or more and 20 parts by mass or less of spindle-shaped calcium carbonate;
(F) 0.1 parts by mass or more and 10 parts by mass or less of a partial ester of a polyhydric alcohol having a valence of 2 to 4;
(G) Alpha olefin oligomer 0.1 parts by mass or more and 10 parts by mass or less.
Hereinafter, when an oxyalkylene unit is described, it means an oxyalkylene unit other than an oxymethylene unit.
　本実施形態のＰＯＭ樹脂組成物においては、ベース樹脂たる（Ａ）線状ポリアセタール共重合体が、ＭＦＲが低く（すなわち高分子量）、コモノマー単位としてのオキシアルキレン単位の含有量が少ないこと、及び当該（Ａ）線状ポリアセタール共重合体と、（Ｂ）分岐又は架橋構造を有するポリアセタール共重合体との組合せにより耐久性の向上を図っている。また、（Ａ）線状ポリアセタール共重合体を用いることで十分な機械特性が得られるが、（Ｂ）分岐又は架橋構造を有するポリアセタール共重合体を含有することで機械特性の更なる向上を図っている。更に、（Ａ）ポリアセタール共重合体１００質量部に対して、（Ｃ）～（Ｇ）成分を所定量含有させることで、摺動特性の向上を図っている。
　以下に、各成分について詳述する。 In the POM resin composition of the present embodiment, the linear polyacetal copolymer (A), which is the base resin, has a low MFR (that is, a high molecular weight) and a low content of oxyalkylene units as comonomer units; (A) A linear polyacetal copolymer and (B) a polyacetal copolymer having a branched or crosslinked structure are combined to improve durability. In addition, although (A) the use of a linear polyacetal copolymer provides sufficient mechanical properties, the addition of (B) a polyacetal copolymer having a branched or crosslinked structure further improves the mechanical properties. ing. Further, by adding predetermined amounts of components (C) to (G) to 100 parts by mass of the polyacetal copolymer (A), the sliding properties are improved.
Each component will be described in detail below.
［（Ａ）線状ポリアセタール共重合体］
　本実施形態においては、ベース樹脂として、線状ポリアセタール共重合体（Ａ）（本明細書において、「（Ａ）成分」ともいう。）を用いる。本実施形態に係る（Ａ）成分は、オキシメチレン単位（－ＣＨ２Ｏ－）を主たる構成単位とし、オキシアルキレン単位を全構成単位に占める割合として０．４モル％以上０．９モル％以下含有する。このような（Ａ）成分を用いることで機械特性の向上を図ることができる。 [(A) Linear polyacetal copolymer]
In this embodiment, a linear polyacetal copolymer (A) (also referred to as “(A) component” in this specification) is used as the base resin. The component (A) according to the present embodiment has oxymethylene units ( --CH.sub.2O--) as main structural units, and the ratio of oxyalkylene units to all structural units is 0.4 mol % or more and 0.9 mol % or less. contains. By using such component (A), mechanical properties can be improved.
　（Ａ）成分の主原料として、トリオキサンが広く用いられる。トリオキサンは、ホルムアルデヒドの環状三量体であり、一般的には酸性触媒の存在下でホルムアルデヒド水溶液を反応させることによって得られ、これを蒸留等の方法で精製して用いられる。トリオキサンは、水、メタノール、蟻酸等の不純物を極力含まないものが好ましい。 Trioxane is widely used as the main raw material for component (A). Trioxane is a cyclic trimer of formaldehyde, and is generally obtained by reacting an aqueous formaldehyde solution in the presence of an acidic catalyst, and is used after being purified by a method such as distillation. Trioxane preferably contains as little impurities as water, methanol, and formic acid.
　本実施形態に係る（Ａ）成分において、全構成単位に占める割合としてオキシアルキレン単位を０．４モル％以上０．９モル％以下含有するが、０．４モル％未満であると熱安定性が不十分となり、０．９モル％を超えると機械特性（引張強度）が劣化する。当該オキシアルキレン単位を全構成単位に占める割合は、０．５モル％以上０．８モル％以下であることが好ましく、０．５モル％以上０．７モル％以下であることがより好ましい。 In the component (A) according to the present embodiment, the oxyalkylene unit is contained in an amount of 0.4 mol% or more and 0.9 mol% or less as a proportion of all structural units. becomes insufficient, and if it exceeds 0.9 mol %, the mechanical properties (tensile strength) deteriorate. The ratio of the oxyalkylene units to all structural units is preferably 0.5 mol % or more and 0.8 mol % or less, and more preferably 0.5 mol % or more and 0.7 mol % or less.
　オキシアルキレン単位としては、例えば、オキシエチレン基、オキシプロピレン基、オキシブチレン基、などが挙げられる。 Examples of oxyalkylene units include an oxyethylene group, an oxypropylene group, an oxybutylene group, and the like.
　オキシアルキレン単位の炭素数は特に限定されるものではないが、２以上４以下であることがより好ましい。 Although the number of carbon atoms in the oxyalkylene unit is not particularly limited, it is more preferably 2 or more and 4 or less.
　オキシアルキレン単位の由来となるコモノマーの例として、単官能環状エーテル化合物及び単官能環状ホルマール化合物から選択される１種以上の化合物が挙げられる。本実施形態において、単官能環状エーテル化合物とは、環状エーテル単位を１分子中に１個有する化合物をいい、単官能環状ホルマール化合物とは、環状ホルマール単位を１分子中に１個有する化合物をいう。具体的には、エチレンオキシド、プロピレンオキシド、ブチレンオキシド、エピクロロヒドリン、エピブロモヒドリン、スチレンオキシド、オキセタン、３，３－ビス（クロルメチル）オキセタン、テトラヒドロフラン、トリオキセパン、１，３－ジオキソラン、エチレングリコールホルマール、プロピレングリコールホルマール、ジエチレングリコールホルマール、トリエチレングリコールホルマール、１，４－ブタンジオールホルマール、１，５－ペンタンジオールホルマール、１，６－ヘキサンジオールホルマール等が挙げられる。 Examples of comonomers from which oxyalkylene units are derived include one or more compounds selected from monofunctional cyclic ether compounds and monofunctional cyclic formal compounds. In the present embodiment, the monofunctional cyclic ether compound refers to a compound having one cyclic ether unit per molecule, and the monofunctional cyclic formal compound refers to a compound having one cyclic formal unit per molecule. . Specifically, ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, epibromohydrin, styrene oxide, oxetane, 3,3-bis(chloromethyl)oxetane, tetrahydrofuran, trioxepane, 1,3-dioxolane, ethylene glycol formal, propylene glycol formal, diethylene glycol formal, triethylene glycol formal, 1,4-butanediol formal, 1,5-pentanediol formal, 1,6-hexanediol formal and the like.
　（Ａ）成分は、耐クリープ特性の向上を図るため、１９０℃、２１６０ｇ荷重下でのメルトフローレート（ＭＦＲ）が１～１２ｇ／１０分のものを用いる。当該メルトフローレートは、好ましくは１．２～１０ｇ／１０分であり、より好ましくは１．５ｇ／１０分以上７ｇ／１０分未満である。
　なお、メルトフローレートは、ＩＳＯ １１３３に準拠して測定される数値である。 Component (A) has a melt flow rate (MFR) of 1 to 12 g/10 minutes at 190° C. under a load of 2160 g in order to improve creep resistance. The melt flow rate is preferably 1.2 to 10 g/10 minutes, more preferably 1.5 g/10 minutes or more and less than 7 g/10 minutes.
The melt flow rate is a numerical value measured according to ISO 1133.
　（Ａ）成分は公知の製造方法によって製造することができる。 (A) component can be produced by a known production method.
［（Ｂ）分岐又は架橋構造を有するポリアセタール共重合体］
　（Ｂ）分岐又は架橋構造を有するポリアセタール共重合体は、（ｂ１）トリオキサンと、（ｂ２）１分子中に環状エーテル単位を３以上４以下有する化合物と、（ｂ３）１分子中に環状エーテル単位を１個有する化合物との共重合体である。本明細書において、（Ｂ）分岐又は架橋構造を有するポリアセタール共重合体を「（Ｂ）成分」ともいう。 [(B) Polyacetal copolymer having a branched or crosslinked structure]
(B) A polyacetal copolymer having a branched or crosslinked structure includes (b1) trioxane, (b2) a compound having 3 or more and 4 or less cyclic ether units in one molecule, and (b3) a cyclic ether unit in one molecule. is a copolymer with a compound having one In this specification, the (B) polyacetal copolymer having a branched or crosslinked structure is also referred to as "(B) component".
（（ｂ１）トリオキサン）
（ｂ１）トリオキサンは、（Ａ）成分で説明したトリオキサンと同じであり、ホルムアルデヒドの環状三量体である。（ｂ１）トリオキサンについてもまた、不純物を極力含まないことが好ましい。 ((b1) trioxane)
(b1) Trioxane is the same as the trioxane described for component (A), and is a cyclic trimer of formaldehyde. (b1) Trioxane is also preferably free of impurities as much as possible.
（（ｂ２）１分子中に環状エーテル単位を３以上４以下有する化合物）
　（ｂ２）１分子中に環状エーテル単位を３以上４以下有する化合物とは、１分子中に、エポキシ単位、グリシジル単位、１，３－ジオキソラン単位、１，４－ブタンジオールホルマール単位、ジエチレングリコールホルマール単位及び１，３，６－トリオキセパン単位等からなる群から選択される環状エーテル単位を３以上４以下有する化合物の総称をいう。環状エーテル単位の個数が２であると、十分な剛性を得られない可能性がある。具体的には、ＩＳＯ１７８に準拠する試験片の曲げ弾性率が２７００ＭＰａ未満である可能性がある。一方、環状エーテル単位の個数が多すぎると、靭性が低下する可能性がある。 ((b2) a compound having 3 or more and 4 or less cyclic ether units in one molecule)
(b2) A compound having 3 to 4 cyclic ether units in one molecule means an epoxy unit, a glycidyl unit, a 1,3-dioxolane unit, a 1,4-butanediol formal unit, and a diethylene glycol formal unit in one molecule. and 1,3,6-trioxepane units. If the number of cyclic ether units is 2, there is a possibility that sufficient rigidity cannot be obtained. Specifically, the flexural modulus of a test piece conforming to ISO178 may be less than 2700 MPa. On the other hand, if the number of cyclic ether units is too large, toughness may decrease.
　また、環状エーテル単位としてはグリシジル単位が好ましく、トリグリシジルエーテル化合物及びテトラグリシジルエーテル化合物が好ましい化合物として挙げられる。その例としては、グリセロールトリグリシジルエーテル、トリメチロールプロパントリグリシジルエーテル、ペンタエリスリトールテトラグリシジルエーテル等が挙げられる。これらの化合物は単独で又は２種以上を併用して（ａ）トリオキサンとの共重合に供することができる。 In addition, the cyclic ether unit is preferably a glycidyl unit, and preferred compounds include triglycidyl ether compounds and tetraglycidyl ether compounds. Examples thereof include glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether and the like. These compounds can be used alone or in combination of two or more for copolymerization with (a) trioxane.
　（ｂ２）１分子中に環状エーテル単位を３以上４以下有する化合物の共重合量は特に限定されるものでないが、目的とする特性を有するポリアセタール樹脂組成物を好適に得ることを踏まえると、共重合量は、（ｂ１）トリオキサン１００質量部に対して０．０１質量部以上１質量部以下であることが好ましく、０．０５質量部以上０．５質量部以下であることがより好ましく、０．１質量部以上０．３質量部以下であることが更に好ましい。 (b2) The copolymerization amount of the compound having 3 or more and 4 or less cyclic ether units in one molecule is not particularly limited. The polymerization amount is preferably 0.01 parts by mass or more and 1 part by mass or less, more preferably 0.05 parts by mass or more and 0.5 parts by mass or less with respect to 100 parts by mass of trioxane (b1). 0.1 part by mass or more and 0.3 part by mass or less is more preferable.
（（ｂ３）１分子中に環状エーテル単位を１個有する化合物）
　（ｂ３）１分子中に環状エーテル単位を１個有する化合物は、（Ｂ）成分を製造する際の重合反応を安定化させると共に、生成した（Ｂ）成分の熱安定性を高められる点で好適である。 ((b3) a compound having one cyclic ether unit in one molecule)
(b3) A compound having one cyclic ether unit in one molecule is suitable for stabilizing the polymerization reaction during the production of component (B) and increasing the thermal stability of the component (B) produced. is.
　（ｂ３）１分子中に環状エーテル単位を１個有する化合物としては、エチレンオキシド、プロピレンオキシド、ブチレンオキシド、エピクロロヒドリン、エピブロモヒドリン、スチレンオキシド、オキセタン、３，３－ビス（クロルメチル）オキセタン、テトラヒドロフラン、トリオキセパン、１，３－ジオキソラン、エチレングリコールホルマール、プロピレングリコールホルマール、ジエチレングリコールホルマール、トリエチレングリコールホルマール、１，４－ブタンジオールホルマール、１，５－ペンタンジオールホルマール、１，６－ヘキサンジオールホルマール等が挙げられる。中でも、エチレンオキシド、１，３－ジオキソラン、１，４－ブタンジオールホルマール、ジエチレングリコールホルマールが好ましい。 (b3) Compounds having one cyclic ether unit in one molecule include ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, epibromohydrin, styrene oxide, oxetane, 3,3-bis(chloromethyl)oxetane , tetrahydrofuran, trioxepane, 1,3-dioxolane, ethylene glycol formal, propylene glycol formal, diethylene glycol formal, triethylene glycol formal, 1,4-butanediol formal, 1,5-pentanediol formal, 1,6-hexanediol formal etc. Among them, ethylene oxide, 1,3-dioxolane, 1,4-butanediol formal, and diethylene glycol formal are preferred.
　（Ｂ）成分における（ｂ３）１分子中に環状エーテル単位を１個有する化合物の共重合量は特に限定されるものでないが、（ｂ１）トリオキサン１００質量部に対して２０質量部以下であることが好ましく、０．０５質量部以上１５質量部以下であることがより好ましく、０．１質量部以上１０質量部以下であることが更に好ましい。 Although the amount of the compound (b3) having one cyclic ether unit in one molecule in the component (B) is not particularly limited, it should be 20 parts by mass or less with respect to 100 parts by mass of the (b1) trioxane. , more preferably 0.05 to 15 parts by mass, and even more preferably 0.1 to 10 parts by mass.
　次いで、本実施形態において使用する（Ｃ）～（Ｇ）成分について、以下に説明する。
　以下の（Ｃ）～（Ｇ）成分は、上記の通り、摺動特性の向上のために添加される。 Next, the components (C) to (G) used in this embodiment will be explained below.
The following components (C) to (G) are added to improve sliding properties as described above.
［（Ｃ）不飽和カルボン酸、不飽和脂肪酸の酸無水物及びこれらの誘導体から選択される少なくとも１種によってオレフィン系重合体が変性された変性オレフィン系重合体］
　本明細書において、上記変性オレフィン系重合体を「（Ｃ）成分」ともいう。本実施形態に係るポリアセタール樹脂組成物おいて、（Ｃ）成分を含有させることで、摺動特性に優れる。逆に、ポリアセタール樹脂組成物おいて、（Ｃ）成分以外のオレフィン系重合体を含有させる場合、摺動特性が劣る。 [(C) Modified olefin polymer obtained by modifying an olefin polymer with at least one selected from unsaturated carboxylic acids, unsaturated fatty acid anhydrides and derivatives thereof]
In this specification, the modified olefin polymer is also referred to as "(C) component". In the polyacetal resin composition according to the present embodiment, by containing the component (C), the sliding properties are excellent. Conversely, when the polyacetal resin composition contains an olefinic polymer other than the component (C), the sliding properties are poor.
　（Ｃ）成分において用いられるオレフィン系重合体（変性前）としては、エチレン、プロピレン、ブテン、ヘキセン、オクテン、ノネン、デセン、ドデセン等のα－オレフィンの単独重合体、及びこれらの２種以上からなるランダム、ブロック又はグラフト共重合体、及びこれらに１，４－ヘキサジエン、ジシクロペンタジエン、５－エチリデン－２－ノルボルネン、２，５－ノルボナジエン等の非共役ジエン成分、ブタジエン、イソプレン、ピペリレン等の共役ジエン成分、アクリル酸、メタクリル酸等のα，β－不飽和酸又はそのエステル等の誘導体、アクリロニトリル、スチレン、α－メチルスチレン等の芳香族ビニル化合物、又は酢酸ビニル等のビニルエステル、ビニルメチルエーテル等のビニルエーテルやこれらのビニル系化合物の誘導体等のコモノマー成分のうちの少なくとも１種を含んでなるランダム、ブロック又はグラフト共重合体等が挙げられ、その重合度、側鎖や分岐の有無や程度、共重合組成比等の如何を問わない。 The olefin polymer (before modification) used in component (C) includes homopolymers of α-olefins such as ethylene, propylene, butene, hexene, octene, nonene, decene, and dodecene, and two or more of these. Random, block or graft copolymers, and non-conjugated diene components such as 1,4-hexadiene, dicyclopentadiene, 5-ethylidene-2-norbornene, 2,5-norbornadiene, butadiene, isoprene, piperylene, etc. Conjugated diene components, α,β-unsaturated acids such as acrylic acid and methacrylic acid, derivatives such as esters thereof, aromatic vinyl compounds such as acrylonitrile, styrene, α-methylstyrene, vinyl esters such as vinyl acetate, and vinyl methyl Examples include random, block or graft copolymers containing at least one comonomer component such as vinyl ethers such as ethers and derivatives of these vinyl compounds, and the degree of polymerization, the presence or absence of side chains and branches, and the like. It does not matter what the degree, copolymer composition ratio, etc. are.
　オレフィン系重合体の例としては、高圧法ポリエチレン、中低圧法ポリエチレン、気相法エチレン－α－オレフィン共重合体、ＬＬＤＰＥ、ポリプロピレン、ポリブテン、エチレン－酢酸ビニル共重合体、エチレン－アクリル酸メチル共重合体、エチレン－アクリル酸エチル共重合体、エチレン－アクリル酸ブチル共重合体、エチレン－プロピレン共重合体、エチレン－プロピレン－ジエン三元共重合体等がある。好ましくは、ポリエチレン、エチレン－アクリル酸メチル共重合体、エチレン－アクリル酸エチル共重合体である。 Examples of olefin polymers include high pressure polyethylene, medium and low pressure polyethylene, gas phase ethylene-α-olefin copolymer, LLDPE, polypropylene, polybutene, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer. polymers, ethylene-ethyl acrylate copolymers, ethylene-butyl acrylate copolymers, ethylene-propylene copolymers, ethylene-propylene-diene terpolymers, and the like. Preferred are polyethylene, ethylene-methyl acrylate copolymer and ethylene-ethyl acrylate copolymer.
　本実施形態において使用される（Ｃ）成分とは、上記のオレフィン系重合体を、アクリル酸、メタクリル酸、マレイン酸、シトラコン酸、イタコン酸、テトラヒドロフタル酸、ナジック酸、メチルナジック酸、アリルコハク酸などの不飽和カルボン酸、及び無水マレイン酸、無水シトラコン酸、無水イタコン酸、テトラヒドロ無水フタル酸、無水ナジック酸、無水メチルナジック酸、アリル無水コハク酸等の不飽和カルボン酸無水物、及びこれらの誘導体等からなる群より選ばれた少なくとも１種で変性したものである。 The component (C) used in the present embodiment includes the above olefin-based polymer, acrylic acid, methacrylic acid, maleic acid, citraconic acid, itaconic acid, tetrahydrophthalic acid, nadic acid, methylnadic acid, and allylsuccinic acid. and unsaturated carboxylic anhydrides such as maleic anhydride, citraconic anhydride, itaconic anhydride, tetrahydrophthalic anhydride, nadic anhydride, methyl nadic anhydride, allyl succinic anhydride, and these It is modified with at least one selected from the group consisting of derivatives and the like.
　好ましい（Ｃ）成分は、そのメルトフローレート（ＭＦＲ）が０．０１～１００ｇ／１０分のものであり、更に好ましいのは、ＭＦＲが０．１～５０ｇ／１０分のものであり、特に好ましいのは、ＭＦＲが０．２～３０ｇ／１０分のものである。尚、メルトフローレート（ＭＦＲ）は、ＩＳＯ　１１３３に準拠して測定される数値である。 Component (C) preferably has a melt flow rate (MFR) of 0.01 to 100 g/10 minutes, more preferably 0.1 to 50 g/10 minutes, and particularly preferably. are those with an MFR of 0.2 to 30 g/10 min. The melt flow rate (MFR) is a numerical value measured in accordance with ISO 1133.
　好ましい（Ｃ）成分の具体例としては、無水マレイン酸で変性されたポリエチレン、ポリプロピレン、エチレン－プロピレン共重合体、エチレン－エチルアクリレート共重合体等が挙げられる。中でも、（Ｃ）成分が無水マレイン酸で変性されたポリエチレンを含有するものであると、ポリアセタール樹脂組成物を成形してなる成形品の摺動特性が高まる点で好ましい。 Specific examples of preferable component (C) include polyethylene modified with maleic anhydride, polypropylene, ethylene-propylene copolymer, ethylene-ethyl acrylate copolymer, and the like. Among them, it is preferable that the component (C) contains polyethylene modified with maleic anhydride, because the sliding properties of the molded product obtained by molding the polyacetal resin composition are enhanced.
　ポリエチレンを無水マレイン酸で変性する変性方法としては、オレフィン系重合体と、不飽和カルボン酸、その無水物、及びそれらの誘導体からなる群より選ばれた少なくとも１種の化合物を、溶液状態又は溶融状態で適当な有機過酸化物等のラジカル開始剤の存在下で加熱して反応させる方法等が好適であるが、特にこれに限定されるものではない。両成分の配合量は、オレフィン系重合体１００質量部に対して、前記化合物０．１質量部以上２０質量部以下、好ましくは０．１質量部以上１０質量部以下が適当である。そのような化合物で変性したオレフィン系重合体中の有効なその化合物の量が少なすぎる場合、（Ａ）成分と（Ｃ）成分との間の親和性が不十分となる場合があり、多すぎる場合、摺動特性等の改善すべき物性を低下させる場合がある。 As a modification method for modifying polyethylene with maleic anhydride, an olefin polymer and at least one compound selected from the group consisting of unsaturated carboxylic acids, anhydrides thereof, and derivatives thereof are added in a solution state or a molten state. A method of heating and reacting in the presence of a radical initiator such as an appropriate organic peroxide under certain conditions is suitable, but the method is not particularly limited to this. The blending amount of both components is suitably 0.1 to 20 parts by mass, preferably 0.1 to 10 parts by mass, per 100 parts by mass of the olefinic polymer. If the effective amount of the compound in the olefinic polymer modified with such a compound is too low, the affinity between components (A) and (C) may be insufficient; In this case, physical properties to be improved such as sliding properties may be deteriorated.
　本実施形態において、（Ｃ）成分は、（Ａ）成分１００質量部に対して、０．５質量部以上１０質量部以下含有させることが好ましく、２質量部以上７質量部以下含有させることがより好ましい。得られるポリアセタール樹脂組成物において、（Ｃ）成分の配合量が０．５質量部未満であると、摩擦摩耗量が増加する可能性があるため、好ましくない。（Ｃ）成分の配合量が１０質量部を超える場合は、機械物性が低下する可能性があるため、好ましくない。 In the present embodiment, component (C) is preferably contained in an amount of 0.5 parts by mass or more and 10 parts by mass or less, and may be contained in an amount of 2 parts by mass or more and 7 parts by mass or less with respect to 100 parts by mass of component (A). more preferred. If the amount of component (C) is less than 0.5 parts by mass in the obtained polyacetal resin composition, the amount of frictional wear may increase, which is not preferable. If the amount of component (C) is more than 10 parts by mass, mechanical properties may deteriorate, which is not preferable.
［（Ｄ）１級アミノ基又は２級アミノ基を有し、数平均分子量が４００以上５００，０００以下であるアルキレングリコール系重合体］
　本明細書において、当該アルキレングリコール系重合体を「（Ｄ）成分」ともいう。本実施形態に係るポリアセタール樹脂組成物において、（Ｄ）成分を含有させることで、摺動特性に優れる。 [(D) Alkylene glycol-based polymer having a primary amino group or a secondary amino group and a number average molecular weight of 400 or more and 500,000 or less]
In this specification, the alkylene glycol-based polymer is also referred to as "(D) component". In the polyacetal resin composition according to the present embodiment, by containing the component (D), the sliding properties are excellent.
　（Ｄ）成分である、１級アミノ基又は２級アミノ基を有するアルキレングリコール系重合体とは、エチレングリコール、プロピレングリコール、テトラメチレングリコールのホモポリマー又はコポリマーであって、その末端又は分子鎖中に１級又は２ 級アミノ基を有するポリマーをいう。更に脂肪酸とのエステル、脂肪族アルコールとのエーテルを形成する等の若干の変性をした重合体でもよい。その例として、ポリエチレングリコール、ポリプロピレングリコール、ポリテトラメチレングリコール、及びこれらの構成単位からなるコポリマーであって、少なくとも１つのアミノプロピル基、アミノオクチル基を有するもの等がある。 Component (D) is an alkylene glycol-based polymer having a primary amino group or a secondary amino group, which is a homopolymer or copolymer of ethylene glycol, propylene glycol, or tetramethylene glycol, at the terminal or in the molecular chain. A polymer having a primary or secondary amino group in Further, it may be a slightly modified polymer such as an ester with a fatty acid or an ether with an aliphatic alcohol. Examples thereof include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymers composed of these constituent units having at least one aminopropyl or aminooctyl group.
　重合体の種類は特に限定されるものでないが、アルキレングリコール系重合体が、脂肪酸とのエステル、脂肪族アルコールとのエーテルを形成する等の若干の変性をした重合体であると、ポリアセタール樹脂組成物を成形してなる成形品の摺動特性が高まる点で好ましい。 The type of polymer is not particularly limited, but if the alkylene glycol polymer is a slightly modified polymer such as forming an ester with a fatty acid or an ether with an aliphatic alcohol, the polyacetal resin composition It is preferable in that the sliding property of a molded product obtained by molding an object is enhanced.
　（Ｄ）成分の数平均分子量は、４００以上５００，０００以下であり、４００以上１００，０００以下であることが好ましく、１，０００以上６，０００以下であることが更に好ましい。これは、（Ｄ）成分の配合により、（Ｃ）成分のポリアセタール樹脂への分散性が改善されるが、（Ｄ）成分の数平均分子量が４００未満では（Ａ）成分又は（Ｃ）成分の高分子材料として持つ機械物性、摺動特性を損ない、数平均分子量が５０万を超えては、溶融粘度が高くなりポリアセタール樹脂に分散させることが困難になるからである。 The number average molecular weight of component (D) is from 400 to 500,000, preferably from 400 to 100,000, and more preferably from 1,000 to 6,000. This is because the dispersibility of component (C) in the polyacetal resin is improved by blending component (D), but if the number average molecular weight of component (D) is less than 400, component (A) or component (C) This is because if the number average molecular weight exceeds 500,000, the melt viscosity becomes high and it becomes difficult to disperse it in the polyacetal resin.
　（Ｄ）成分の配合量は、（Ａ）成分に対して０．０１質量部以上５質量部以下であり、０．１質量部以上４質量部以下であることがより好ましく、０．３質量部以上３質量部以下であることが更に好ましく、１質量部以上２質量部以下であることが特に好ましい。中でも、（Ｄ）成分の配合量が１質量部以上であると、ポリアセタール樹脂組成物を成形してなる成形品の摺動特性を大きく改善できる点で好ましい。（Ｄ）成分が０．０１質量部未満であると、成形品の摺動特性の改質効果を充分得られず、また５質量部を超えると機械物性を低下させ、好ましくない。 The blending amount of component (D) is 0.01 parts by mass or more and 5 parts by mass or less, more preferably 0.1 parts by mass or more and 4 parts by mass or less, relative to component (A), and 0.3 parts by mass. It is more preferably 1 part or more and 3 parts by mass or less, and particularly preferably 1 part or more and 2 parts by mass or less. Above all, when the amount of the component (D) is 1 part by mass or more, it is preferable in that the sliding properties of a molded product obtained by molding the polyacetal resin composition can be greatly improved. If the amount of component (D) is less than 0.01 parts by mass, the effect of improving the sliding properties of the molded product cannot be sufficiently obtained, and if it exceeds 5 parts by mass, the mechanical properties are unfavorably lowered.
［（Ｅ）紡錘状炭酸カルシウム］
　本明細書において、上記（Ｅ）紡錘状炭酸カルシウムを「（Ｅ）成分」ともいう。本実施形態において、（Ａ）線状ポリアセタール樹脂に配合される（Ｅ）成分は軽質炭酸カルシウムに属し、その形状が紡錘状をなしている粒子である。紡錘状とは、糸をつむぐ際に使用される紡錘に似た形、すなわち円柱状で中央部が太く、両端が次第に細くなっている形を言うが、本実施形態で使用する（Ｅ）成分たる紡錘状炭酸カルシウムは、概ねこれに類似する形状を有するものであればよい。その平均粒子径は０．１～１μｍ、平均粒子長さは０．５～１０μｍ、粒子長さ／粒子径の平均値は、２～１０のものが好ましく、３～６がより好ましい。ここで、粒子径とは紡錘状粒子の最大直径部（通常は長さ方向のほぼ中央部）の直径、粒子長さとは紡錘状粒子の長さを指す。また、平均粒子径及び平均粒子長さは、紡錘状炭酸カルシウムを電子顕微鏡で撮影し、写真から無作為に選択した５０個の粒子についてその粒子径及び粒子長さを読み取り、その平均値を求める方法で測定した値を指す。 [(E) Spindle-shaped calcium carbonate]
In the present specification, the above (E) spindle-shaped calcium carbonate is also referred to as "(E) component". In the present embodiment, the component (E) blended in the linear polyacetal resin (A) is particles belonging to light calcium carbonate and having a spindle shape. The spindle shape refers to a shape similar to a spindle used for spinning yarn, that is, a cylindrical shape with a thick central portion and gradually tapered ends. Component (E) used in this embodiment. The barrel-shaped calcium carbonate may have a shape generally similar to this. The average particle diameter is preferably 0.1 to 1 μm, the average particle length is 0.5 to 10 μm, and the average value of particle length/particle diameter is preferably 2 to 10, more preferably 3 to 6. Here, the particle diameter refers to the diameter of the spindle-shaped particle at its maximum diameter (usually, approximately the center in the longitudinal direction), and the particle length refers to the length of the spindle-shaped particle. In addition, the average particle diameter and average particle length are obtained by photographing spindle-shaped calcium carbonate with an electron microscope, reading the particle diameter and particle length of 50 particles randomly selected from the photograph, and calculating the average value. It refers to the value measured by the method.
　このような特定の（Ｅ）成分としては白石工業（株）製のシルバーＷ、ＰＣ、ＰＣＸ、カルライトＳＡ等が例示される。本実施形態において使用する（Ｅ）成分は、表面処理剤で表面処理されたものが好ましく、特に、アミノシランで表面処理されたものが好ましい。このような表面処理された（Ｅ）成分としては白石工業（株）製のＳＬ－１０１が例示される。 Examples of such a specific (E) component include Silver W, PC, PCX, and Callite SA manufactured by Shiraishi Kogyo Co., Ltd. Component (E) used in the present embodiment is preferably surface-treated with a surface treating agent, particularly preferably aminosilane. SL-101 manufactured by Shiraishi Kogyo Co., Ltd. is exemplified as the component (E) that has undergone such a surface treatment.
　（Ｅ）成分の配合量は、（Ａ）成分に対して０．１質量部以上２０質量部以下であり、０．１質量部以上１質量部以下であることがより好ましい。（Ｅ）成分が０．１質量部未満であると摩擦摩耗量が増加する可能性があり、また２０質量部を超える表面性が悪化する可能性があるため、好ましくない。 The blending amount of component (E) is 0.1 to 20 parts by mass, more preferably 0.1 to 1 part by mass, relative to component (A). If the amount of component (E) is less than 0.1 parts by mass, frictional wear may increase, and if it exceeds 20 parts by mass, the surface properties may deteriorate, which is not preferable.
［（Ｆ）２価以上４価以下の多価アルコールの部分エステル］
　本明細書において、当該多価アルコールの部分エステルを「（Ｆ）成分」ともいう。本実施形態に係るポリアセタール樹脂組成物において、（Ｆ）成分を含有させることで、表面性及び摺動特性に優れる。 [(F) Partial Ester of Dihydric to Tetravalent Polyhydric Alcohol]
In this specification, the partial ester of the polyhydric alcohol is also referred to as "(F) component". In the polyacetal resin composition according to the present embodiment, by including the component (F), the surface properties and sliding properties are excellent.
　従来より、ポリアセタール樹脂組成物の成分として、潤滑剤を用いることが知られている。また、潤滑剤として、鉱油、炭化水素、脂肪酸、脂肪族アルコール、脂肪酸と脂肪族アルコールよりなる脂肪族エステル、多価アルコールの部分エステル及び／又はフルエステル、カルボン酸と無機酸とのエステル、脂肪酸とアミン化合物とのアミド、金属石鹸、天然ワックス、シリコーン及びその誘導体、置換ジフェニルエーテル等が知られている。しかしながら、本実施形態においては、（Ｆ）成分としての部分エステルと、後に説明する（Ｇ）成分としてのアルファオレフィンオリゴマーとの両方が必須の構成要素である。潤滑剤として、これら（Ｆ）成分及び（Ｇ）成分以外の他の潤滑剤を含有していたとしても、本実施形態ほど、表面性に優れるとはいえないため、好ましくない。 Conventionally, it has been known to use a lubricant as a component of a polyacetal resin composition. In addition, as lubricants, mineral oils, hydrocarbons, fatty acids, fatty alcohols, fatty esters composed of fatty acids and fatty alcohols, partial esters and/or full esters of polyhydric alcohols, esters of carboxylic acids and inorganic acids, fatty acids and amine compounds, metal soaps, natural waxes, silicones and their derivatives, substituted diphenyl ethers, and the like. However, in this embodiment, both the partial ester as the (F) component and the alpha olefin oligomer as the (G) component described later are essential constituent elements. Even if a lubricant other than these components (F) and (G) is contained as a lubricant, it cannot be said that the surface properties are as excellent as in the present embodiment, and thus it is not preferable.
　（Ｆ）成分の具体例として、グリセリンモノステアレート、グリセリンジステアレート、グリセリンモノベヘネート、ペンタエリスリトールモノステアレート等が挙げられる。（Ｆ）成分としての部分エステルに関し、エステルが部分エステルでないと、ポリアセタール樹脂組成物を成形してなる成形品の表面性及び摺動特性が劣る点で好ましくない。 Specific examples of the component (F) include glycerin monostearate, glycerin distearate, glycerin monobehenate, pentaerythritol monostearate, and the like. Regarding the partial ester as the component (F), if the ester is not a partial ester, it is not preferable in that the molded article obtained by molding the polyacetal resin composition has poor surface properties and sliding properties.
　（Ｆ）成分の配合量は、（Ａ）成分に対して０．１質量部以上１０質量部以下であり、０．５質量部以上２質量部以下であることがより好ましい。（Ｆ）成分が０．１質量部未満であると摩擦摩耗量が増加する可能性があり、また１０質量部を超えると染み出しが発生する可能性があるため、好ましくない。 The blending amount of component (F) is 0.1 parts by mass or more and 10 parts by mass or less, more preferably 0.5 parts by mass or more and 2 parts by mass or less relative to component (A). If the amount of component (F) is less than 0.1 parts by mass, frictional wear may increase, and if it exceeds 10 parts by mass, bleeding may occur, which is not preferable.
［（Ｇ）アルファオレフィンオリゴマー］
　本明細書において、当該オリゴマーを「（Ｇ）成分」ともいう。本実施形態に係るポリアセタール樹脂組成物において、（Ｇ）成分を含有させることで、摺動特性に優れる。 [(G) Alpha Olefin Oligomer]
In this specification, the oligomer is also referred to as "(G) component". In the polyacetal resin composition according to the present embodiment, by including the component (G), the sliding properties are excellent.
　（Ｇ）成分の配合量は、（Ａ）成分に対して０．１質量部以上１０質量部以下であり、１質量部以上５質量部以下であることがより好ましい。（Ｇ）成分が０．１質量部未満であると、ポリアセタール樹脂組成物を成形してなる成形品の摺動特性が劣る可能性があり、また１０質量部を超えると染み出し、剥離が発生する可能性があるため、好ましくない。 The blending amount of component (G) is 0.1 parts by mass or more and 10 parts by mass or less, more preferably 1 part by mass or more and 5 parts by mass or less relative to component (A). If the amount of component (G) is less than 0.1 part by mass, the molded product obtained by molding the polyacetal resin composition may have poor sliding properties. It is not preferable because it may
［他の安定剤及び添加剤］
　本実施形態に係るポリアセタール樹脂組成物は、公知の各種安定剤を更に添加して安定性を補強することができる。また、目的とする用途に応じてその物性を改善するために、公知の各種の添加剤を更に配合し得る。 [Other stabilizers and additives]
The stability of the polyacetal resin composition according to the present embodiment can be enhanced by further adding various known stabilizers. Moreover, in order to improve the physical properties according to the intended use, various known additives may be added.
　添加剤として、各種の着色剤、離型剤、核剤、帯電防止剤、その他の界面活性剤、異種ポリマー（前記のグラフト共重合体以外）等が挙げられる。また、本実施形態の目的とする組成物の性能を大幅に低下させない範囲内であれば、無機・有機・金属等の繊維状、粉粒状、板状の充填剤を１種又は２種混合使用することもできる。 Additives include various colorants, mold release agents, nucleating agents, antistatic agents, other surfactants, heterogeneous polymers (other than the above-mentioned graft copolymer), and the like. In addition, within a range that does not significantly reduce the performance of the composition targeted by the present embodiment, fibrous, powdery, granular, plate-like fillers such as inorganic, organic, and metal are used alone or in combination. You can also
［ポリアセタール樹脂組成物の調製］
　本実施形態に係るポリアセタール樹脂組成物の調製は、従来の樹脂組成物調製法として一般に用いられる公知の方法により容易に調製される。例えば、（１）組成物を構成する全成分を混合し、これを押出機に供給して溶融混練し、ペレット状の組成物を得る方法、（２）組成物を構成する成分の一部を押出機の主フィード口から、残余成分をサイドフィード口から供給して溶融混練し、ペレット状の組成物を得る方法、（３）押出し等により一旦組成の異なるペレットを調製し、そのペレットを混合して所定の組成に調整する方法等を採用できる。 [Preparation of polyacetal resin composition]
The polyacetal resin composition according to the present embodiment can be easily prepared by a known method generally used as a conventional resin composition preparation method. For example, (1) a method of mixing all the components that make up the composition, feeding this to an extruder and melt-kneading to obtain a pellet-like composition, (2) a method of obtaining a pellet-like composition, A method of obtaining a composition in the form of pellets by supplying the remaining components from the main feed port of the extruder and melt-kneading them from the side feed port. It is also possible to adopt a method of adjusting the composition to a predetermined composition.
＜樹脂製歯車＞
　本実施形態の樹脂製歯車は、上述のポリアセタール樹脂組成物を成形してなる。上記の本実施形態のポリアセタール樹脂組成物と同様に、本実施形態の樹脂製歯車は、耐久性、機械特性、及び摺動特性に優れる。 <Resin gear>
The resin gear of this embodiment is formed by molding the polyacetal resin composition described above. As with the polyacetal resin composition of the present embodiment, the resin gear of the present embodiment is excellent in durability, mechanical properties, and sliding properties.
　本実施形態に係るポリアセタール樹脂組成物を用いて樹脂製歯車を成形する方法としては特に限定はなく、当該技術分野で知られている各種方法を採用することができる。例えば、本実施形態に係るポリアセタール樹脂組成物を押出機に投入して溶融混練してペレット化し、このペレットを所定の金型を装備した射出成形機に投入し、射出成形することで作製することができる。 The method for molding a resin gear using the polyacetal resin composition according to this embodiment is not particularly limited, and various methods known in the technical field can be employed. For example, the polyacetal resin composition according to the present embodiment is put into an extruder, melt-kneaded and pelletized, and the pellets are put into an injection molding machine equipped with a predetermined mold and injection molded. can be done.
　その他、本実施形態の樹脂製歯車は、本実施形態に係るポリアセタール樹脂組成物を板状又は棒状に成形したあと、それらを切削加工などの一般的な成形加工により成形することができる。 In addition, the resin gear of this embodiment can be formed by molding the polyacetal resin composition according to this embodiment into a plate-like or rod-like shape, and then molding them by general molding such as cutting.
　本実施形態の樹脂製歯車が適用できる歯車の種類としては、特に限定はないが、例えば、平歯車、ラック、内歯車、はすば歯車、はすば内歯車、はすばラック、やまば歯車、すぐばかさ歯車、まがりばかさ歯車、ゼロールかさ歯車、ねじ歯車、円筒ウォームギヤ等が挙げられる。 The types of gears to which the resin gear of the present embodiment can be applied are not particularly limited. Gears, straight bevel gears, spiral bevel gears, zerol bevel gears, screw gears, cylindrical worm gears, and the like.
　以下に、実施例により本実施形態を更に具体的に説明するが、本実施形態は以下の実施例に限定されるものではない。 The present embodiment will be described in more detail below with reference to examples, but the present embodiment is not limited to the following examples.
（１）（Ａ）線状ポリアセタール共重合体の調製
　以下のようにして、線状ポリアセタール共重合体Ａ－１～Ａ－６を得た。 (1) (A) Preparation of Linear Polyacetal Copolymer Linear polyacetal copolymers A-1 to A-6 were obtained as follows.
《線状ポリアセタール共重合体Ａ－１》
　重合反応装置として連続式二軸重合機を用いた。この重合機は、外側に加熱用又は冷却用の媒体を通すためのジャケットを備えており、その内部には撹拌、推進用の多数のパドルを付した２本の回転軸が長手方向に設けられている。この二軸重合機のジャケットに８０℃の熱媒を通し、２本の回転軸を一定の速度で回転させながら、その一端に、トリオキサン１０．０ｋｇ／ｈｒとコモノマーとしての１，３－ジオキソラン０．１３ｋｇ／ｈｒと連鎖移動剤としてのメチラール３．０ｇ／ｈｒを連続的に供給した。これに触媒として三フッ化ホウ素をガス状で用い、全モノマー量に対し２０質量ｐｐｍになるように連続供給し、重合を行った。重合機の他端に設けられた吐出口から粗ポリアセタール共重合体を排出し、排出された反応生成物は速やかに破砕機に通しながら、トリエチルアミンを０．０５質量％含有する６０℃の水溶液に加え触媒を失活させた。更に、分離、洗浄、乾燥することで、粗ポリアセタール共重合体を得た。次いで、この粗ポリアセタール共重合体１００質量部に対して、トリエチルアミン５質量％水溶液を４質量部、ペンタエリスリチル－テトラキス〔３－（３，５－ジ－ｔｅｒｔ－ブチル－４－ヒドロキシフェニル）プロピオネート〕を０．３質量部添加して、二軸押出機にて２１０℃で溶融混練し不安定部分を除去し、線状ポリアセタール共重合体Ａ－１を得た。得られた線状ポリアセタール共重合体Ａ－１の性状は、ＭＦＲ＝２．５ｇ／１０分、オキシエチレン単位＝０．５モル％(対オキシメチレン単位＋オキシエチレン単位)であった。 <<Linear Polyacetal Copolymer A-1>>
A continuous twin-screw polymerization machine was used as a polymerization reactor. This polymerization machine is equipped with a jacket for passing a medium for heating or cooling on the outside, and two rotating shafts with many paddles for stirring and propelling are provided in the longitudinal direction inside. ing. A heat medium of 80° C. is passed through the jacket of the twin-screw polymerizer, and while the two rotating shafts are rotated at a constant speed, 10.0 kg/hr of trioxane and 0 of 1,3-dioxolane as a comonomer are added to one end of the shaft. .13 kg/hr and 3.0 g/hr of methylal as a chain transfer agent were continuously fed. A gaseous boron trifluoride was used as a catalyst and continuously supplied to the mixture so as to give a concentration of 20 ppm by mass based on the total amount of monomers to carry out polymerization. The crude polyacetal copolymer is discharged from the discharge port provided at the other end of the polymerization machine, and the discharged reaction product is quickly passed through a crusher and added to an aqueous solution at 60 ° C. containing 0.05% by mass of triethylamine. was added to deactivate the catalyst. Furthermore, by separating, washing and drying, a crude polyacetal copolymer was obtained. Next, with respect to 100 parts by mass of this crude polyacetal copolymer, 4 parts by mass of a 5% by mass triethylamine aqueous solution, pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate ] was added, melt-kneaded at 210° C. with a twin-screw extruder, and unstable portions were removed to obtain a linear polyacetal copolymer A-1. Properties of the obtained linear polyacetal copolymer A-1 were MFR=2.5 g/10 min, oxyethylene unit=0.5 mol % (relative to oxymethylene unit+oxyethylene unit).
《線状ポリアセタール共重合体Ａ－２》
　上記線状ポリアセタール共重合体Ａ－１と同様にして線状ポリアセタール共重合体Ａ－２を得た。ただし、メチラール量は０．５ｇ／ｈｒとした。
　線状ポリアセタール共重合体Ａ－２の性状は、ＭＦＲ＝１．５ｇ／１０分、オキシエチレン単位＝０．５モル％(対オキシメチレン単位＋オキシエチレン単位)であった。 <<Linear Polyacetal Copolymer A-2>>
A linear polyacetal copolymer A-2 was obtained in the same manner as the linear polyacetal copolymer A-1. However, the amount of methylal was set to 0.5 g/hr.
The properties of the linear polyacetal copolymer A-2 were MFR=1.5 g/10 min, oxyethylene unit=0.5 mol % (relative to oxymethylene unit+oxyethylene unit).
《線状ポリアセタール共重合体Ａ－３》
　上記線状ポリアセタール共重合体Ａ－１と同様にして線状ポリアセタール共重合体Ａ－３を得た。ただし、１，３－ジオキソラン量は０．１９ｋｇ／ｈｒとした。
　線状ポリアセタール共重合体Ａ－３の性状は、ＭＦＲ＝２．５ｇ／１０分、オキシエチレン単位＝０．７モル％(対オキシメチレン単位＋オキシエチレン単位)であった。 <<Linear Polyacetal Copolymer A-3>>
A linear polyacetal copolymer A-3 was obtained in the same manner as the linear polyacetal copolymer A-1. However, the amount of 1,3-dioxolane was 0.19 kg/hr.
The properties of the linear polyacetal copolymer A-3 were MFR=2.5 g/10 min, oxyethylene unit=0.7 mol % (relative to oxymethylene unit+oxyethylene unit).
《線状ポリアセタール共重合体Ａ－４》
　上記線状ポリアセタール共重合体Ａ－１と同様にして線状ポリアセタール共重合体Ａ－４を得た。ただし、メチラール量は１１．０ｇ／ｈｒとした。
　線状ポリアセタール共重合体Ａ－４の性状は、ＭＦＲ＝９．０ｇ／１０分、オキシエチレン単位＝０．５モル％(対オキシメチレン単位＋オキシエチレン単位)であった。 <<Linear Polyacetal Copolymer A-4>>
A linear polyacetal copolymer A-4 was obtained in the same manner as the linear polyacetal copolymer A-1. However, the amount of methylal was set to 11.0 g/hr.
The properties of the linear polyacetal copolymer A-4 were MFR=9.0 g/10 min and oxyethylene unit=0.5 mol % (relative to oxymethylene unit+oxyethylene unit).
《線状ポリアセタール共重合体Ａ－５》
　上記線状ポリアセタール共重合体Ａ－１と同様にして線状ポリアセタール共重合体Ａ－５を得た。ただし、１，３－ジオキソラン量は０．２９Ｋｇ／ｈｒとした。
　線状ポリアセタール共重合体Ａ－５の性状は、ＭＦＲ＝２．５ｇ／１０分、オキシエチレン単位＝１．２モル％(対オキシメチレン単位＋オキシエチレン単位)であった。 <<Linear Polyacetal Copolymer A-5>>
A linear polyacetal copolymer A-5 was obtained in the same manner as the linear polyacetal copolymer A-1. However, the amount of 1,3-dioxolane was 0.29 kg/hr.
The properties of the linear polyacetal copolymer A-5 were MFR=2.5 g/10 min and oxyethylene units=1.2 mol % (relative to oxymethylene units+oxyethylene units).
《線状ポリアセタール共重合体Ａ－６》
　上記線状ポリアセタール共重合体Ａ－１と同様にして線状ポリアセタール共重合体Ａ－６を得た。ただし、メチラール量は１３．５ｇ／ｈｒとした。
　線状ポリアセタール共重合体Ａ－６の性状は、ＭＦＲ＝１４．０ｇ／１０分、オキシエチレン単位＝０．５モル％（対オキシメチレン単位＋オキシエチレン単位）であった。 <<Linear Polyacetal Copolymer A-6>>
A linear polyacetal copolymer A-6 was obtained in the same manner as the linear polyacetal copolymer A-1. However, the amount of methylal was 13.5 g/hr.
The properties of the linear polyacetal copolymer A-6 were MFR=14.0 g/10 min, oxyethylene unit=0.5 mol % (relative to oxymethylene unit+oxyethylene unit).
（メルトフローレート（ＭＦＲ）の測定）
　上記のようにして得られた線状ポリアセタール共重合体Ａ－１～Ａ－６のメルトフローレート（ＭＦＲ）を、ＩＳＯ　１１３３に従って測定した。測定結果を表１に示す。 (Measurement of melt flow rate (MFR))
The melt flow rate (MFR) of the linear polyacetal copolymers A-1 to A-6 obtained as described above was measured according to ISO 1133. Table 1 shows the measurement results.
（２）（Ｂ）分岐又は架橋構造を有するポリアセタール共重合体の調製
《ポリアセタール共重合体Ｂ－１（３官能）》
　上記線状ポリアセタール共重合体Ａ－１と同様にしてポリアセタール共重合体Ｂ－１を得た。ただし、コモノマーとしての１，３－ジオキソランの代わりに、第１コモノマー（ｂ２）としてトリメチロールプロパントリグリシジルエーテル（ＴＭＰＴＧＥ）(３官能)１０ｇ／ｈｒを、第２コモノマー（ｂ３）として１，３－ジオキソラン０．１１ｋｇ／ｈｒを使用し、メチラール量は４．０ｇ／ｈｒとした。
　ポリアセタール共重合体Ｂ－１の性状は、ＭＦＲ＝１．５ｇ／１０分、オキシエチレン単位＝０．５モル％(対オキシメチレン単位＋オキシエチレン単位)であった。また、ＴＭＰＴＧＥの含量は０．１質量％であった。 (2) (B) Preparation of Polyacetal Copolymer Having Branched or Crosslinked Structure <<Polyacetal Copolymer B-1 (Trifunctional)>>
A polyacetal copolymer B-1 was obtained in the same manner as the linear polyacetal copolymer A-1. However, instead of 1,3-dioxolane as a comonomer, 10 g/hr of trimethylolpropane triglycidyl ether (TMPTGE) (trifunctional) as the first comonomer (b2) and 1,3-dioxolane as the second comonomer (b3) 0.11 kg/hr of dioxolane was used and the amount of methylal was 4.0 g/hr.
The properties of the polyacetal copolymer B-1 were MFR=1.5 g/10 min and oxyethylene units=0.5 mol % (relative to oxymethylene units+oxyethylene units). Also, the content of TMPTGE was 0.1% by mass.
《ポリアセタール共重合体Ｂ－２（４官能）》
　上記線状ポリアセタール共重合体Ａ－１と同様にしてポリアセタール共重合体Ｂ－２を得た。ただし、コモノマーとしての１，３－ジオキソランの代わりに、第１コモノマー（ｂ２）としてペンタエリスリトールテトラグリシジルエーテル（ＰＥＴＧＥ） (４官能)１０ｇ／ｈｒを、第２コモノマー（ｂ３）として１，３－ジオキソラン０．１１Ｋｇ／ｈｒを使用し、メチラール量は４．０ｇ／ｈｒとした。
　ポリアセタール共重合体Ｂ－２の性状は、ＭＦＲ＝１．５ｇ／１０分、オキシエチレン単位＝０．５モル％(対オキシメチレン単位＋オキシエチレン単位)であった。また、ＰＥＴＧＥの含量は０．１質量％であった。 <<Polyacetal copolymer B-2 (tetrafunctional)>>
A polyacetal copolymer B-2 was obtained in the same manner as the linear polyacetal copolymer A-1. However, instead of 1,3-dioxolane as a comonomer, pentaerythritol tetraglycidyl ether (PETGE) (tetrafunctional) 10 g/hr as the first comonomer (b2) and 1,3-dioxolane as the second comonomer (b3) 0.11 Kg/hr was used and the amount of methylal was 4.0 g/hr.
The properties of the polyacetal copolymer B-2 were MFR=1.5 g/10 min and oxyethylene unit=0.5 mol % (relative to oxymethylene unit+oxyethylene unit). Also, the content of PETGE was 0.1% by mass.
《ポリアセタール共重合体Ｂ－３（２官能）》
　上記線状ポリアセタール共重合体Ａ－１と同様にしてポリアセタール共重合体Ｂ－３を得た。ただし、コモノマーとしての１，３－ジオキソランの代わりに、第１コモノマー（ｂ２）としてブタンジオールジグリシジルエーテル（ＢＤＧＥ） (２官能)１０ｇ／ｈｒを、第２コモノマー（ｂ３）として１，３－ジオキソラン０．１１Ｋｇ／ｈｒを使用し、メチラール量は４．０ｇ／ｈｒとした。
　ポリアセタール共重合体Ｂ－３の性状は、ＭＦＲ＝１．５ｇ／１０分、オキシエチレン単位＝０．５モル％(対オキシメチレン単位＋オキシエチレン単位)であった。また、ＢＤＧＥの含量は０．１質量％であった。 <<Polyacetal copolymer B-3 (bifunctional)>>
A polyacetal copolymer B-3 was obtained in the same manner as the linear polyacetal copolymer A-1. However, instead of 1,3-dioxolane as a comonomer, butanediol diglycidyl ether (BDGE) (bifunctional) 10 g/hr as the first comonomer (b2) and 1,3-dioxolane as the second comonomer (b3) 0.11 Kg/hr was used and the amount of methylal was 4.0 g/hr.
The properties of the polyacetal copolymer B-3 were MFR=1.5 g/10 min and oxyethylene unit=0.5 mol % (relative to oxymethylene unit+oxyethylene unit). Also, the content of BDGE was 0.1% by mass.
［実施例１～７、比較例１～７］
　上記＜（１）（Ａ）線状ポリアセタール共重合体の調製＞及び（２）＜（Ｂ）分岐又は架橋構造を有するポリアセタール共重合体の調製＞で得た（Ａ）成分及び（Ｂ）成分並びに下記（Ｃ）～（Ｇ）成分を表１に示す割合（単位は質量部）でプリブレンドした。その後、１ヶ所のベント口を有する３０ｍｍ径の二軸押出機の主フィード口に投入して溶融混合（押出条件：Ｌ／Ｄ＝３５、押出し温度＝２００℃、スクリュー回転数＝１２０ｒｐｍ、ベント真空度＝－７００ｍｍＨｇ、吐出量＝１２ｋｇ／ｈｒ）し、ペレット状のポリアセタール樹脂組成物を得た。 [Examples 1 to 7, Comparative Examples 1 to 7]
Components (A) and (B) obtained in the above <(1) Preparation of (A) linear polyacetal copolymer> and (2) <Preparation of polyacetal copolymer having branched or crosslinked structure> In addition, the following components (C) to (G) were preblended in proportions shown in Table 1 (unit: parts by mass). After that, it was introduced into the main feed port of a 30 mm diameter twin-screw extruder having one vent port and melt-mixed (extrusion conditions: L / D = 35, extrusion temperature = 200 ° C., screw rotation speed = 120 rpm, vent vacuum pressure = -700 mmHg, discharge rate = 12 kg/hr) to obtain a polyacetal resin composition in the form of pellets.
（Ｃ）変性オレフィン系重合体
　（Ｃ－１）無水マレイン酸変性低密度ポリエチレン（ＬＤＰＥ）（製品名：タフマーＭＭ６８５０，三井化学（株）製）
　（Ｃ－２）無水マレイン酸変性エチレン－アクリル酸エチルコポリマー（ＥＥＡ）（製品名：ＨＰＲ　ＡＲ２０１１，三井デュポンポリケミカル（株）製）
（Ｄ）１級アミノ基又は２級アミノ基を有し、数平均分子量が４００以上５００，０００以下であるアルキレングリコール系重合体
　（Ｄ－１）両末端アミン変性ポリエチレングリコール（ＰＥＧ）（製品名：ケミスタットＹ－４００，数平均分子量：４，０００，三洋化成工業（株）製）
（Ｅ）紡錘状炭酸カルシウム
　（Ｅ－１）紡錘状炭酸カルシウム（製品名：ＳＬ－１０１，平均粒子径：０．３μｍ，平均粒子長さ：１．２μｍ，白石工業（株）製）
（Ｆ）多価アルコールの部分エステル
　（Ｆ－１）グリセリンモノステアレート（製品名：リケマールＳ１００，理研ビタミン（株）製）
（Ｇ）アルファオレフィンオリゴマー
　（Ｇ－１）アルファオレフィンオリゴマー（製品名：ルーカントＨＣ６００，三井化学（株）製） (C) Modified olefin polymer (C-1) Maleic anhydride-modified low-density polyethylene (LDPE) (product name: Toughmer MM6850, manufactured by Mitsui Chemicals, Inc.)
(C-2) Maleic anhydride-modified ethylene-ethyl acrylate copolymer (EEA) (product name: HPR AR2011, manufactured by DuPont Mitsui Polychemicals Co., Ltd.)
(D) Alkylene glycol polymer having a primary amino group or secondary amino group and a number average molecular weight of 400 or more and 500,000 or less (D-1) Amine-modified polyethylene glycol (PEG) at both ends (product name : Chemistat Y-400, number average molecular weight: 4,000, manufactured by Sanyo Chemical Industries Co., Ltd.)
(E) Spindle-shaped calcium carbonate (E-1) Spindle-shaped calcium carbonate (product name: SL-101, average particle size: 0.3 μm, average particle length: 1.2 μm, manufactured by Shiraishi Kogyo Co., Ltd.)
(F) Partial ester of polyhydric alcohol (F-1) Glycerin monostearate (product name: Rikemal S100, manufactured by Riken Vitamin Co., Ltd.)
(G) Alpha olefin oligomer (G-1) Alpha olefin oligomer (product name: Lucant HC600, manufactured by Mitsui Chemicals, Inc.)
［評価］
　実施例及び比較例に係るペレット状のポリアセタール共重合体の耐クリープ特性、機械特性（引張強度）及び静音性を以下のようにして評価した。 [evaluation]
The creep resistance, mechanical properties (tensile strength) and quietness of the pellet-shaped polyacetal copolymers of Examples and Comparative Examples were evaluated as follows.
（１）耐クリープ特性（クリープ破断時間）
　厚さ ４ｍｍのＩＳＯ　Ｔｙｐｅ－Ａ試験片を成形し、クリープ試験機を用いて、８０℃環境下で、２０ＭＰａの荷重をかけクリープ試験を実施し、破断するまでの時間（クリープ破断時間（ｈ））で比較した。３本を測定し、その平均値をクリープ破断時間とした。 (1) Creep resistance (creep rupture time)
An ISO Type-A test piece with a thickness of 4 mm was molded, and a creep test was performed using a creep tester under an environment of 80 ° C. under a load of 20 MPa, and the time until rupture (creep rupture time (h) ) were compared. Three samples were measured, and the average value was taken as the creep rupture time.
（２）機械特性（引張強度）
　各実施例・比較例において、ＩＳＯ５２７に従って、得られた樹脂組成物ペレットを用いて試験片を作製して引張強度を測定した（ＩＳＯ５２７－２／１Ａ／５０）。 (2) Mechanical properties (tensile strength)
In each example and comparative example, according to ISO527, the obtained resin composition pellets were used to prepare test pieces and measure the tensile strength (ISO527-2/1A/50).
（３）静音性（鳴き音）
　ＪＩＳ　Ｋ　７２１８　Ａ法に従い、以下の試験機を用い、荷重を０ＭＰａから段階的に増大させていき、異音が発生したときの面圧を得る。
　試験片：中空円筒形（内径：２０ｍｍ、外径：２５．６ｍｍ、高さ：１５ｍｍ）
　試験機：（株）オリエンテック製、スラスト式摩擦摩耗試験機ＥＦＭ－III－Ｅ
　環境：２３℃，５０％ＲＨ
　線速度：１０ｍｍ／ｓｅｃ
　相手材：同材 (3) Silence (noise)
According to JIS K 7218 A method, the following test machine is used, and the load is increased stepwise from 0 MPa to obtain the surface pressure when abnormal noise occurs.
Test piece: hollow cylindrical (inner diameter: 20 mm, outer diameter: 25.6 mm, height: 15 mm)
Tester: Thrust type friction wear tester EFM-III-E manufactured by Orientec Co., Ltd.
Environment: 23°C, 50% RH
Linear velocity: 10mm/sec
Mating material: Same material
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１より、実施例１～７のポリアセタール樹脂組成物はいずれの評価結果も良好な結果が得られたことが分かる。それに対して、（Ａ）成分におけるオキシエチレン単位の割合が過多の比較例１は、耐クリープ特性及び機械強度に劣っていた。また、（Ａ）成分のＭＦＲが過大である比較例２は、耐クリープ特性に劣っていた。更に、（Ｂ）成分として、（ｂ２）１分子中に環状エーテル単位を３以上４以下有する化合物を用いなかった比較例３は、耐クリープ特性及び機械強度に劣っていた。更に、（Ｂ）成分の含有量が過少又は（Ｂ）成分を含有していない比較例４、６は、耐クリープ特性及び機械強度に劣っていた。更に、（Ｂ）成分の含有量が過多の比較例５は、耐クリープ特性に劣っていた。更に、（Ｂ）～（Ｇ）成分を含有していない比較例７は、静音性に劣っていた。すなわち、比較例７は摺動特性に劣っていた。 From Table 1, it can be seen that the polyacetal resin compositions of Examples 1 to 7 gave good results in all evaluations. On the other hand, Comparative Example 1, in which the proportion of oxyethylene units in component (A) was excessive, was inferior in creep resistance and mechanical strength. Comparative Example 2, in which the component (A) had an excessively high MFR, was inferior in creep resistance. Furthermore, Comparative Example 3, in which the compound (b2) having 3 to 4 cyclic ether units per molecule was not used as the component (B), was inferior in creep resistance and mechanical strength. Furthermore, Comparative Examples 4 and 6, in which the content of component (B) was too small or did not contain component (B), were inferior in creep resistance and mechanical strength. Furthermore, Comparative Example 5, in which the content of component (B) was excessive, was inferior in creep resistance. Furthermore, Comparative Example 7, which did not contain components (B) to (G), was inferior in quietness. That is, Comparative Example 7 was inferior in sliding properties.

Claims (2)

  1. 　（Ａ）オキシメチレン単位を主たる構成成分とし、コモノマー単位としてオキシメチレン単位以外のオキシアルキレン単位を全構成単位に占める割合として０．４モル％以上０．９モル％以下含有し、メルトフローレートが１～１２ｇ／１０分である線状ポリアセタール共重合体１００質量部に対し、
    　（Ｂ）（ｂ１）トリオキサン、（ｂ２）１分子中に環状エーテル単位を３以上４以下有する化合物及び（ｂ３）１分子中に環状エーテル単位を１個有する化合物の共重合体である、分岐又は架橋構造を有するポリアセタール共重合体１質量部以上１０質量部以下と、
    　（Ｃ）不飽和カルボン酸、不飽和脂肪酸の酸無水物及びこれらの誘導体から選択される少なくとも１種によってオレフィン系重合体が変性された変性オレフィン系重合体０．５質量部以上１０質量部以下と、
    　（Ｄ）１級アミノ基又は２級アミノ基を有し、数平均分子量が４００以上５００，０００以下であるアルキレングリコール系重合体０．０１質量部以上５質量部以下と、
    　（Ｅ）紡錘状炭酸カルシウム０．１質量部以上２０質量部以下と、
    　（Ｆ）２価以上４価以下の多価アルコールの部分エステル０．１質量部以上１０質量部以下と、
    　（Ｇ）アルファオレフィンオリゴマー０．１質量部以上１０質量部以下と、
    　を含有する、ポリアセタール樹脂組成物。     (A) contains an oxymethylene unit as a main component, and contains 0.4 mol% or more and 0.9 mol% or less of oxyalkylene units other than oxymethylene units as comonomer units, and the melt flow rate is For 100 parts by mass of the linear polyacetal copolymer that is 1 to 12 g / 10 minutes,
    (B) (b1) trioxane, (b2) a compound having 3 or more and 4 or less cyclic ether units in one molecule, and (b3) a copolymer of a compound having one cyclic ether unit in one molecule, branched or 1 part by mass or more and 10 parts by mass or less of a polyacetal copolymer having a crosslinked structure;
    (C) 0.5 parts by mass or more and 10 parts by mass or less of a modified olefin polymer obtained by modifying an olefin polymer with at least one selected from unsaturated carboxylic acids, unsaturated fatty acid anhydrides, and derivatives thereof; When,
    (D) 0.01 parts by mass or more and 5 parts by mass or less of an alkylene glycol polymer having a primary amino group or a secondary amino group and a number average molecular weight of 400 or more and 500,000 or less;
    (E) 0.1 parts by mass or more and 20 parts by mass or less of spindle-shaped calcium carbonate;
    (F) 0.1 parts by mass or more and 10 parts by mass or less of a partial ester of a polyhydric alcohol having a valence of 2 or more and 4 or less;
    (G) an alpha olefin oligomer of 0.1 parts by mass or more and 10 parts by mass or less;
    A polyacetal resin composition containing
  2. 　請求項１に記載のポリアセタール樹脂組成物を成形してなる樹脂製歯車。 A resin gear formed by molding the polyacetal resin composition according to claim 1.
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JP2012116883A (en) * 2010-11-29 2012-06-21 Polyplastics Co Polyacetal resin composition
JP2012136656A (en) * 2010-12-27 2012-07-19 Polyplastics Co Polyacetal resin composition
JP5847261B1 (en) * 2014-09-29 2016-01-20 ポリプラスチックス株式会社 Polyacetal resin composition and sliding member
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JP2018002830A (en) * 2016-06-30 2018-01-11 ポリプラスチックス株式会社 Polyacetal resin composition for molding plate-like molded body, plate-like molded body, and carrier plate of window regulator
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JP2002003694A (en) * 2000-06-23 2002-01-09 Polyplastics Co Polyacetal resin composition
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JP5847261B1 (en) * 2014-09-29 2016-01-20 ポリプラスチックス株式会社 Polyacetal resin composition and sliding member
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