JP2020034164A - Cellulose-containing resin gear - Google Patents

Abstract

To provide a resin gear having both sufficient durability and quietness in practical use.SOLUTION: Provided is a resin gear comprising (A) a thermoplastic resin, and (B) cellulose nanofibers having an average fiber diameter of 1000 nm or less, wherein the arithmetic average surface roughness Sa of a slide surface with other gear teeth is 3.0 μm or less. In one embodiment, the resin gear is used with a torque of 3 N/m or more. In a preferred embodiment, the resin gear is exposed to hot water at 80°C for 24 hours, and then the change in the water absorption dimension when held for 120 hours under a temperature of 80°C and a relative humidity of 57% is 3% or less.SELECTED DRAWING: None

Description

  The present invention relates to a resin composition containing cellulose.

  Thermoplastic resins are light and have excellent processing characteristics, and are therefore widely used in various fields such as automobile parts, electric / electronic parts, office equipment housings, and precision parts. However, a single resin is often insufficient in mechanical properties, slidability, thermal stability, dimensional stability, and the like, and a composite of a resin and various inorganic materials is generally used.

  A resin composition in which a thermoplastic resin is reinforced with a reinforcing material that is an inorganic filler such as glass fiber, carbon fiber, talc, or clay has a high specific gravity, and thus has a problem that the weight of the obtained resin molded article increases. In addition, using a resin composition containing glass fiber, a round bar can be extruded and then cut into a specific shape, or even if a thick part is formed by injection molding, a void ( (Vacuum-like cavity) is generated, and there is a problem that the durability is inferior due to stress concentration. This is because voids (vacuum-like cavities) are generated inside the molded body due to the difference between the external cooling rate and the internal cooling rate. Therefore, in recent years, cellulose having a low environmental load has been used as a new reinforcing material for resins.

It is known that cellulose has, as its simple properties, a high elastic modulus comparable to aramid fiber and a lower linear expansion coefficient than glass fiber. Further, the true density is as low as 1.56 g / cm ^3, and glass (density 2.4 to 2.6 g / cm ³ ) or talc (density 2.7 g / cm ³ ) used as a reinforcing material for general thermoplastic resin is used. It is overwhelmingly lighter than ³ ).

  Cellulose has a wide variety of sources, including those made from trees, hemp, cotton, kenaf, cassava and the like. Furthermore, bacterial cellulose such as Nata de coco is also known. These natural resources as raw materials are present in large quantities on the earth, and techniques for utilizing cellulose as a filler in resins have attracted attention for their effective use.

  CNF (cellulose nanofiber) is obtained by using pulp or the like as a raw material, hydrolyzing a hemicellulose part to make it weak, and then defibrating it by a pulverization method such as a high-pressure homogenizer, a microfluidizer, a ball mill or a disk mill. It is known that they form a highly dispersed state or network at a level called fine nano-dispersion in water.

  However, in order to mix CNF in the resin, it is necessary to dry and powder CNF. However, CNF becomes a strong aggregate from a finely dispersed state in the process of being separated from water, and is difficult to redisperse. is there. This cohesive force is expressed by hydrogen bonding due to the hydroxyl group of cellulose, and is said to be very strong.

Therefore, in order to exhibit sufficient performance, it is necessary to relax the hydrogen bond due to the hydroxyl group of cellulose. Further, even if the hydrogen bond can be sufficiently relaxed, it is difficult to maintain the defibrated state (nanometer size (that is, less than 1 μm)) in the resin.
A composition in which these cellulose nanofibers (hereinafter, may be referred to as CNF) are composited with various resins as a filler is disclosed.

  For example, Patent Literature 1 describes a slidable resin composition using cellulose in which a hydroxyl group on the cellulose surface is substituted with a hydrophobic group. Patent Document 2 describes a resin gear made of an apatite compound and a polyamide. Patent Document 3 discloses an electric power steering apparatus using glass fiber and polyamide resin and having a surface roughness of 0.15 or less in arithmetic average roughness Ra.

JP-A-2017-171698 JP 2001-289309 A JP 2006-44306 A

  However, in Patent Document 1, the sliding properties of the compound of cellulose and polyoxymethylene, polypropylene or polyethylene are evaluated by relatively common sliding tests such as a pin-on-disk test and a journal bearing test. There is no mention of the durability of the gear molded piece in actual use. Further, Patent Document 2 describes the tensile strength and tensile elongation of a polyamide resin gear using a nanomaterial, but does not mention the durability, quietness, etc. of the gear in actual use. Patent Document 3 describes surface roughness of glass fiber and polyamide resin in a specific shape, and a method of using a lubricant, but does not mention durability and noise reduction of a gear.

  In other words, in the prior art, it is difficult to reduce the voids inside the thick molded body and improve the durability and the quietness of the gear, and there has been a demand for a gear in which these are improved. An object of the present invention is to solve the above-mentioned problems and to provide a resin gear that achieves both sufficient durability and quietness in practical use.

  The present inventors have conducted intensive studies to solve the above problems, and as a result, the thermoplastic resin contains a specific cellulose, and the arithmetic average surface roughness of the sliding surface with other gear teeth. The present inventors have found that a resin gear having Sa of 3.0 μm or less can solve the above-mentioned problems while being a thick resin molded product, and have accomplished the present invention.

That is, the present invention includes the following embodiments.
[1] (A) a thermoplastic resin, and (B) a cellulose nanofiber having an average fiber diameter of 1000 nm or less, and an arithmetic average surface roughness Sa of a sliding surface with another gear tooth is 3.0 μm or less. And a resin gear used at a torque of 3 N / m or more.
[2] (A) a thermoplastic resin, and (B) a cellulose nanofiber having an average fiber diameter of 1000 nm or less, and an arithmetic average surface roughness Sa of a sliding surface with another gear tooth is 3.0 μm or less. Is a resin gear.
[3] The above-mentioned embodiment 1, in which the dimensional change in water absorption when exposed to hot water at 80 ° C. for 24 hours and then kept at 80 ° C. and a relative humidity of 57% for 120 hours to absorb water is 3% or less. Or the resin gear according to 2.
[4] The resin gear according to any of the above aspects 1 to 3, wherein the maximum size of voids in the resin gear is 1.0 μm or less.
[5] The resin gear according to any one of the above aspects 1 to 4, which is used at a torque of 5 N / m or more.
[6] The resin gear according to any one of the above aspects 1 to 5, which is used at a torque of 10 N / m or more.
[7] (A) one kind of thermoplastic resin selected from the group consisting of polyolefin resin, polyamide resin, polyester resin, polyacetal resin, polyacrylic resin, polyphenylene ether resin, and polyphenylene sulfide resin The resin gear according to any one of the above aspects 1 to 6, which is the above resin.
[8] The resin gear according to the above aspect 7, wherein (A) the thermoplastic resin is at least one resin selected from the group consisting of polyamide and polyacetal.
[9] The resin gear according to any one of the first to eighth aspects, further comprising (C) a surface modifier.
[10] The resin gear according to the above aspect 9, wherein the (C) surface modifier has a number average molecular weight of 200 to 10,000.
[11] The resin gear according to the above aspect 9 or 10, wherein (C) the surface modifier is contained in an amount of 1 to 50 parts by mass relative to 100 parts by mass of the cellulose nanofiber (B).
[12] The resin gear according to any of the above aspects 1 to 11, which comprises (D) a metal ion component.
[13] The resin gear according to the above aspect 12, comprising (D) a metal ion component in an amount of 0.005 to 5 parts by mass based on 100 parts by mass of the thermoplastic resin (A).
[14] The resin gear according to any one of the above aspects 1 to 13, which comprises (E) a sliding agent component.
[15] The resin gear according to the above aspect 14, comprising (E) a sliding agent component in an amount of 0.01 to 5 parts by mass based on 100 parts by mass of the thermoplastic resin (A).
[16] The resin gear according to the above aspect 14 or 15, wherein (E) the melting point of the sliding agent component is from 40 to 150 ° C.
[17] The resin gear according to any of the above aspects 1 to 16, wherein the module is 2.0 or less.
[18] A gear driving body, comprising: the resin gear according to any one of the above aspects 1 to 17;
[19] The gear driving body according to the above aspect 18, wherein the motor is a motor having an operating speed of 10,000 rpm or less.

  According to the present invention, there is provided a resin gear having both sufficient durability and low noise in practical use.

  Hereinafter, exemplary embodiments of the present invention will be specifically described below, but the present invention is not limited to these embodiments.

  The resin gear of this embodiment includes (A) a thermoplastic resin and (B) cellulose nanofiber having an average fiber diameter of 1000 nm or less, and has an arithmetic average surface roughness of a sliding surface with another gear tooth. Sa has 3.0 μm or less.

<< (A) thermoplastic resin >>
The thermoplastic resin (A) that can be used in the present invention typically has a number average molecular weight of 5000 or more. The number average molecular weight of the present disclosure is a value measured using GPC (gel permeation chromatography) in terms of standard polymethyl methacrylate. (A) Examples of the thermoplastic resin include a crystalline resin having a melting point in the range of 100 ° C to 350 ° C, or an amorphous resin having a glass transition temperature in the range of 100 to 250 ° C. (A) The thermoplastic resin may be composed of one or more polymers which may be a homopolymer or a copolymer.

  The melting point of the crystalline resin as used herein refers to a peak top of an endothermic peak that appears when the temperature is raised from 23 ° C. at a rate of 10 ° C./min using a differential scanning calorimeter (DSC). Refers to temperature. When two or more endothermic peaks appear, it indicates the peak top temperature of the endothermic peak on the highest temperature side. At this time, the enthalpy of the endothermic peak is preferably at least 10 J / g, more preferably at least 20 J / g. In the measurement, it is desirable to use a sample which is once heated to a temperature condition of not lower than the melting point + 20 ° C. to melt the resin, and then cooled to 23 ° C. at a rate of 10 ° C./min.

  The glass transition temperature of the amorphous resin as used herein refers to a value measured at an applied frequency of 10 Hz by using a dynamic viscoelasticity measuring device while increasing the temperature from 23 ° C. at a rate of 2 ° C./min. The temperature at the peak top of the peak at which the storage modulus is greatly reduced and the loss modulus is maximized. When two or more peaks of the loss elastic modulus appear, it indicates the peak top temperature of the highest temperature peak. The measurement frequency at this time is desirably at least once every 20 seconds in order to increase the measurement accuracy. The method of preparing the measurement sample is not particularly limited. From the viewpoint of eliminating the influence of molding distortion, it is preferable to use a cut piece of a hot press molded product, and the size (width and thickness) of the cut piece is as small as possible. Smaller is more desirable from the viewpoint of heat conduction.

  (A) As the thermoplastic resin, polyamide-based resin, polyester-based resin, polyacetal-based resin, polycarbonate-based resin, polyacryl-based resin, polyphenylene ether-based resin (modified by blending or graft-polymerizing polyphenylene ether with another resin) Modified polyphenylene ether), polyarylate resin, polysulfone resin, polyphenylene sulfide resin, polyethersulfone resin, polyketone resin, polyphenylene ether ketone resin, polyimide resin, polyamideimide resin, polyetherimide Resin, polyurethane resin, polyolefin resin (for example, α-olefin (co) polymer), and various ionomers.

  (A) Preferred specific examples of the thermoplastic resin include high-density polyethylene, low-density polyethylene (for example, linear low-density polyethylene), polypropylene, polymethylpentene, cyclic olefin-based resin, poly1-butene, poly1-pentene, Polymethylpentene, ethylene / α-olefin copolymer, ethylene / butene copolymer, EPR (ethylene / propylene copolymer), modified ethylene / butene copolymer, EEA (ethylene / ethyl acrylate copolymer), modified EEA, modified EPR, modified EPDM (ethylene-propylene-diene terpolymer), ionomer, α-olefin copolymer, modified IR (isoprene rubber), modified SEBS (styrene-ethylene-butylene-styrene copolymer) , Halogenated isobutylene-paramethylstyrene copolymer, d. Tylene-acrylic acid modified product, ethylene-vinyl acetate copolymer and its acid modified product, copolymer of (ethylene and / or propylene) and (unsaturated carboxylic acid and / or unsaturated carboxylic acid ester), (ethylene And / or propylene) and (unsaturated carboxylic acid and / or unsaturated carboxylic acid ester) polyolefins obtained by metal salification of at least a part of the carboxyl groups of conjugated dienes and vinyl aromatic hydrocarbons. Block copolymers, hydrides of block copolymers of conjugated dienes and vinyl aromatic hydrocarbons, copolymers of other conjugated diene compounds with non-conjugated olefins, natural rubber, various butadiene rubbers, various styrene-butadiene copolymers Combined rubber, isoprene rubber, butyl rubber, bromide of isobutylene and p-methylstyrene copolymer, halogen Butyl rubber, acrylonitrilobutadiene rubber, chloroprene rubber, ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, styrene-isoprene copolymer rubber, styrene-isoprene-butadiene copolymer rubber, isoprene-butadiene Acrylic and acrylonitrile such as copolymer rubber, chlorosulfonated polyethylene, acrylic rubber, epichlorohydrin rubber, polysulfide rubber, silicone rubber, fluorine rubber, urethane rubber, polyvinyl chloride, polystyrene, polyacrylate, polymethacrylate, etc. Cellulose resins such as acrylonitrile-based copolymer, acrylonitrile-butanediene-styrene (ABS) resin, acrylonitrile-styrene (AS) resin, cellulose acetate, etc. Le / ethylene copolymer, vinyl chloride / vinyl acetate copolymer, ethylene / vinyl acetate copolymer, and ethylene / saponified like vinyl acetate copolymer.

  These may be used alone or in combination of two or more. When two or more kinds are used in combination, they may be used as a polymer alloy. In addition, a resin obtained by modifying the above-described thermoplastic resin with at least one compound selected from unsaturated carboxylic acids, acid anhydrides, and derivatives thereof can also be used.

  Among these, from the viewpoint of heat resistance, moldability, design properties and mechanical properties, polyolefin resins, polyamide resins, polyester resins, polyacetal resins, polyacrylic resins, polyphenylene ether resins, and polyphenylene sulfide resins One or more resins selected from the group consisting of

  Among them, polyolefin resin, polyamide resin, polyester resin, polyacetal resin, polyacrylic resin, polyphenylene ether resin, and one or more resins selected from the group consisting of polyphenylene sulfide resin, particularly polyamide One or more resins selected from the group consisting of a series resin and a polyacetal series resin are more preferable from the viewpoint of handleability and cost.

  The polyolefin-based resin is a polymer obtained by polymerizing a monomer unit containing an olefin (for example, an α-olefin). Specific examples of the polyolefin-based resin include, but are not particularly limited to, ethylene-based (co) weight exemplified by low-density polyethylene (for example, linear low-density polyethylene), high-density polyethylene, ultra-low-density polyethylene, and ultra-high-molecular-weight polyethylene. Coal, polypropylene, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, and other polypropylene-based (co) polymers, ethylene-acrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene And glycidyl methacrylate copolymers and other monomer units.

  Here, the most preferable polyolefin-based resin includes polypropylene. Particularly, polypropylene having a melt mass flow rate (MFR) of 3 g / 10 min or more and 30 g / 10 min or less measured at 230 ° C. under a load of 21.2 N according to ISO 1133 is preferable. The lower limit of the MFR is more preferably 5 g / 10 minutes, still more preferably 6 g / 10 minutes, and most preferably 8 g / 10 minutes. Further, the upper limit is more preferably 25 g / 10 minutes, still more preferably 20 g / 10 minutes, and most preferably 18 g / 10 minutes. The MFR desirably does not exceed the above upper limit from the viewpoint of improving the toughness of the composition, and desirably does not exceed the above lower limit from the viewpoint of fluidity of the composition.

  In order to increase the affinity with cellulose, an acid-modified polyolefin-based resin can also be suitably used. The acid can be appropriately selected from maleic acid, fumaric acid, succinic acid, phthalic acid and anhydrides thereof, and polycarboxylic acids such as citric acid. Among these, maleic acid or its anhydride is preferred because of its high modification rate. The modification method is not particularly limited, but a method is generally used in which the resin is heated to a melting point or higher and melt-kneaded in the presence / absence of peroxide. As the polyolefin resin to be acid-modified, any of the above-mentioned polyolefin resins can be used, and polypropylene is particularly preferably used.

  The acid-modified polyolefin-based resin may be used alone, but is preferably used in combination with an unmodified polyolefin-based resin in order to adjust the modification rate of the composition. For example, when using a mixture of unmodified polypropylene and acid-modified polypropylene, the ratio of the acid-modified polypropylene to the total polypropylene is preferably 0.5% by mass to 50% by mass. A more preferred lower limit is 1% by mass, further preferably 2% by mass, still more preferably 3% by mass, particularly preferably 4% by mass, and most preferably 5% by mass. Further, a more preferable upper limit is 45% by mass, further preferably 40% by mass, still more preferably 35% by mass, particularly preferably 30% by mass, and most preferably 20% by mass. In order to maintain the interface strength with cellulose, the lower limit is preferably greater than or equal to the lower limit, and in order to maintain ductility as a resin, the upper limit is preferably equal to or less than the upper limit.

  The melt mass flow rate (MFR) of the acid-modified polypropylene measured at 230 ° C. under a load of 21.2 N according to the preferred ISO 1133 is preferably 50 g / 10 min or more in order to increase the affinity with the cellulose interface. preferable. A more preferred lower limit is 100 g / 10 minutes, still more preferably 150 g / 10 minutes, and most preferably 200 g / 10 minutes. There is no particular upper limit, but the upper limit is 500 g / 10 minutes from the viewpoint of maintaining the mechanical strength. By setting the MFR within this range, it is possible to enjoy the advantage that the MFR is easily present at the interface between the cellulose and the resin.

  The polyamide-based resin that is preferable as the thermoplastic resin is not particularly limited, but includes polyamide 6, polyamide 11, polyamide 12, and the like obtained by a polycondensation reaction of lactams; 1,6-hexanediamine, 2-methyl-1,5 -Pentanediamine, 1,7-heptanediamine, 2-methyl-1-6-hexanediamine, 1,8-octanediamine, 2-methyl-1,7-heptanediamine, 1,9-nonanediamine, 2-methyl- Diamines such as 1,8-octanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, m-xylylenediamine, and butanedioic acid, pentanedioic acid, and hexanedioic acid , Heptane diacid, octane diacid, nonane diacid, decane diacid, benzene-1,2-dicarboxylic acid, ben Polyamide 6 obtained as a copolymer with dicarboxylic acids such as cyclohexane-1,3-dicarboxylic acid and cyclohexane-1,4-dicarboxylic acid such as zen-1,3-dicarboxylic acid and benzene-1,4 dicarboxylic acid. , 6, polyamide 6,10, polyamide 6,11, polyamide 6,12, polyamide 6, T, polyamide 6, I, polyamide 9, T, polyamide 10, T, polyamide 2M5, T, polyamide MXD, 6, polyamide 6 , C, polyamides 2M5, C, etc .; and copolymers of these copolymers (for example, polyamides 6, T / 6, I).

  Among these polyamide resins, aliphatic polyamides such as polyamide 6, polyamide 11, polyamide 12, polyamide 6,6, polyamide 6,10, polyamide 6,11 and polyamide 6,12, polyamide 6, C, polyamide 2M5, C The alicyclic polyamide is more preferable.

  Although the terminal carboxyl group concentration of the polyamide resin is not particularly limited, the lower limit is preferably 20 μmol / g, more preferably 30 μmol / g. Further, the upper limit of the terminal carboxyl group concentration is preferably 150 μmol / g, more preferably 100 μmol / g, and still more preferably 80 μmol / g.

  In the polyamide-based resin, the carboxyl terminal group ratio ([COOH] / [total terminal group]) to the preferable total terminal group is more preferably 0.30 to 0.95. The lower limit of the carboxyl end group ratio is more preferably 0.35, even more preferably 0.40, and most preferably 0.45. The upper limit of the carboxyl terminal group ratio is more preferably 0.90, still more preferably 0.85, and most preferably 0.80. The carboxyl terminal group ratio is desirably 0.30 or more from the viewpoint of dispersibility of the (B) cellulose nanofiber in the composition, and 0.95 or less from the viewpoint of the color tone of the obtained composition. Is desirable.

  As a method for adjusting the terminal group concentration of the polyamide resin, a known method can be used. For example, a diamine compound, a monoamine compound, a dicarboxylic acid compound, a monocarboxylic acid compound, an acid anhydride, a monoisocyanate, a monoacid halide, a monoester, a monoalcohol, etc., so as to have a predetermined terminal group concentration during polymerization of polyamide. A method in which a terminal adjuster that reacts with a terminal group is added to the polymerization solution may be used.

  Examples of the terminal regulator that reacts with a terminal amino group include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, and isobutyric acid. Aliphatic monocarboxylic acids such as cyclohexane carboxylic acid; aromatic monocarboxylic acids such as benzoic acid, toluic acid, α-naphthalene carboxylic acid, β-naphthalene carboxylic acid, methyl naphthalene carboxylic acid, and phenyl acetic acid Carboxylic acids; and a plurality of mixtures arbitrarily selected from these. Among them, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid are preferred from the viewpoints of reactivity, sealed terminal stability, and price. And at least one terminal adjuster selected from the group consisting of benzoic acid and benzoic acid, and acetic acid is most preferred.

  Examples of a terminal adjuster that reacts with a terminal carboxyl group include, for example, aliphatic amines such as methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, and dibutylamine. Monoamines; alicyclic monoamines such as cyclohexylamine and dicyclohexylamine; aromatic monoamines such as aniline, toluidine, diphenylamine, and naphthylamine, and any mixtures thereof. Among them, from the viewpoints of reactivity, boiling point, stability of a sealed end, price, etc., at least one selected from the group consisting of butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine and aniline. Terminal modifiers are preferred.

The concentration of these amino terminal groups and carboxyl terminal groups is preferably determined from the integrated value of the characteristic signal corresponding to each terminal group by ¹ H-NMR in terms of accuracy and simplicity. As a method for determining the concentration of these terminal groups, a method described in JP-A-7-228775 is specifically recommended. When this method is used, deuterated trifluoroacetic acid is useful as a measuring solvent. Further, the number of times of integration of ¹ H-NMR requires at least 300 scans even when measured by an instrument having a sufficient resolution. In addition, the concentration of the terminal group can be measured by a titration measurement method as described in JP-A-2003-055549. However, in order to minimize the influence of mixed additives, lubricants, and the like, quantification by ¹ H-NMR is more preferable.

  The polyamide resin preferably has an intrinsic viscosity [η] measured in concentrated sulfuric acid at 30 ° C. of 0.6 to 2.0 dL / g, and 0.7 to 1.4 dL / g. Is more preferable, 0.7 to 1.2 dL / g is further preferable, and 0.7 to 1.0 dL / g is particularly preferable. Use of the polyamide resin having an intrinsic viscosity in a preferable range, and particularly preferable range among them, greatly enhances fluidity in a mold at the time of injection molding of a resin composition, and gives an effect of improving appearance of a molded piece. be able to.

  In the present disclosure, “intrinsic viscosity” is synonymous with viscosity generally called intrinsic viscosity. A specific method for determining this viscosity is to measure ηsp / c of several measurement solvents having different concentrations in 96% concentrated sulfuric acid at a temperature of 30 ° C., and to determine the respective ηsp / c and the concentration (c ) And extrapolating the concentration to zero. The value extrapolated to zero is the intrinsic viscosity. Details of these are described in, for example, pages 291 to 294 of Polymer Process Engineering (Prentice-Hall, Inc. 1994).

  At this time, it is desirable from the viewpoint of accuracy that the number of the measurement solvents having different concentrations be at least four. The recommended concentrations of the different viscometric solutions are preferably at least 4 points: 0.05 g / dL, 0.1 g / dL, 0.2 g / dL, 0.4 g / dL.

  The polyester resin preferable as the thermoplastic resin is not particularly limited, but includes polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polybutylene succinate (PBS), polybutylene succinate adipate ( PBSA), polybutylene adipate terephthalate (PBAT), polyarylate (PAR), polyhydroxyalkanoic acid (PHA) (a polyester resin composed of 3-hydroxyalkanoic acid), polylactic acid (PLA), polycarbonate (PC) and the like. One or more kinds can be used. Among these, more preferred polyester-based resins include PET, PBS, PBSA, PBT, and PEN, and more preferably, PBS, PBSA, and PBT.

  Further, the polyester resin, the terminal group can be freely changed depending on the monomer ratio at the time of polymerization and the presence or absence and the amount of the terminal stabilizer, but the ratio of the carboxyl terminal group to the total terminal group of the polyester resin. ([COOH] / [all terminal groups]) is preferably 0.30 to 0.95. The lower limit of the carboxyl terminal group ratio is more preferably 0.35, further preferably 0.40, and most preferably 0.45. The upper limit of the carboxyl terminal group ratio is more preferably 0.90, further preferably 0.85, and most preferably 0.80. The carboxyl terminal group ratio is desirably 0.30 or more from the viewpoint of dispersibility of the (B) cellulose nanofiber in the composition, and 0.95 or less from the viewpoint of the color tone of the obtained composition. Is desirable.

  Polyacetal resins preferred as thermoplastic resins include homopolyacetals using formaldehyde as a raw material and copolyacetals containing trioxane as a main monomer and, for example, 1,3-dioxolane as a comonomer component, and both are usable. However, from the viewpoint of thermal stability during processing, copolyacetal can be preferably used. Particularly, the amount of the comonomer component (for example, 1,3-dioxolane) is preferably in the range of 0.01 to 4 mol%. A more preferred lower limit of the comonomer component amount is 0.05 mol%, further preferably 0.1 mol%, and particularly preferably 0.2 mol%. A more preferred upper limit is 3.5 mol%, still more preferably 3.0 mol%, particularly preferably 2.5 mol%, and most preferably 2.3 mol%. From the viewpoint of thermal stability during extrusion and molding, the lower limit is preferably within the above range, and from the viewpoint of mechanical strength, the upper limit is preferably within the above range.

<< (B) Cellulose nanofiber whose average fiber diameter is 1000 nm or less >>
Next, (B) a cellulose nanofiber having an average fiber diameter of 1000 nm or less (also referred to as “(B) cellulose nanofiber” in the present disclosure) that can be used in the present invention will be described in detail.
(B) Preferable examples of the cellulose nanofiber having an average fiber diameter of 1000 nm or less are not particularly limited. For example, one or more kinds of cellulose fibers obtained from cellulose pulp or modified products of these celluloses can be used. Among these, from the viewpoints of stability, performance, and the like, one or more modified cellulose products can be preferably used.

  The production method of the cellulose nanofiber is not particularly limited.For example, after the raw pulp is cut and treated with hot water of 100 ° C. or more, the hemicellulose portion is hydrolyzed and weakened, and then a high-pressure homogenizer, a microfluidizer, a ball mill, It can be obtained by defibrating by a pulverization method using a disk mill or the like.

  (B) The average fiber diameter of the cellulose nanofiber is 1000 nm or less, preferably 500 nm or less, more preferably 200 nm or less, from the viewpoint of obtaining good mechanical strength (particularly tensile modulus) of the resin gear. The average fiber diameter is preferably smaller, but from the viewpoint of processing easiness, it is preferably 10 nm or more, more preferably 20 nm or more, and further preferably 30 nm or more. The average fiber diameter is a value obtained as a spherical equivalent diameter (volume average particle diameter) of the particles when the integrated volume becomes 50% by a laser diffraction / scattering particle size distribution analyzer.

The average fiber diameter can be measured by the following method. (B) A cellulose nanofiber having a solid content of 40% by mass was placed in a planetary mixer (for example, 5DM-03-R, manufactured by Shinagawa Kogyosho Co., Ltd., hook type stirring blade) at 126 rpm at room temperature under normal pressure. The mixture was kneaded for 0.5 min, then made into a pure water suspension at a concentration of 0.5% by mass, and a high-shear homogenizer (for example, Nippon Seiki Co., Ltd., trade name “Excel Auto Homogenizer ED-7” processing conditions) was used. The dispersion was performed at 15,000 rpm for 5 minutes, and a centrifugal separator (for example, trade name “6800 type centrifuge”, rotor type RA-400 type, manufactured by Kubota Shoji Co., Ltd.) was used. Processing conditions: centrifugal force: 39200 m ² / The supernatant obtained by centrifugation at s for 10 minutes is collected, and the supernatant is further centrifuged at 116000 m ² / s for 45 minutes, and the supernatant after centrifugation is collected. Using this supernatant, a laser diffraction / scattering particle size distribution analyzer (for example, trade name "LA-910" or trade name "LA-950" manufactured by Horiba Seisakusho Co., Ltd.), ultrasonic treatment 1 minute, refractive index 1. The 50% integrated particle diameter in the volume frequency particle size distribution obtained in 20) (that is, the spherical equivalent diameter of the particle when the integrated volume becomes 50% with respect to the volume of the entire particle) is defined as the volume average particle diameter. .

  In a typical embodiment, the L / D ratio of (B) the cellulose nanofiber having an average fiber diameter of 1000 nm or less is 20 or more. The lower limit of L / D of the cellulose nanofiber is preferably 30, more preferably 40, more preferably 50, and even more preferably 100. Although the upper limit is not particularly limited, it is preferably 10,000 or less from the viewpoint of handleability. In order to exhibit good mechanical properties of the resin gear of the present disclosure with a small amount of the cellulose nanofiber, it is desirable that the L / D ratio of the cellulose nanofiber be in the above range.

  In the present disclosure, the length, diameter, and L / D ratio of the cellulose nanofiber can be determined by using an aqueous dispersion of the cellulose nanofiber with a high-shear homogenizer (for example, Nippon Seiki Co., Ltd., trade name “Excel Auto Homogenizer ED”). -7 "), processing conditions: an aqueous dispersion dispersed at a rotation speed of 15,000 rpm for 5 minutes, diluted with pure water to 0.1 to 0.5% by mass, cast on mica, and air-dried. The obtained sample is used as a measurement sample, and measured by an optical microscope, a high-resolution scanning microscope (SEM), or an atomic force microscope (AFM). Specifically, the length (L) and diameter (D) of 100 randomly selected cellulose nanofibers in an observation field of view in which the magnification is adjusted so that at least 100 cellulose nanofibers are observed. Is measured, and the ratio (L / D) is calculated. In addition, the length and diameter of the cellulose nanofiber of the present disclosure is a number average value of the 100 celluloses.

  The length, diameter, and L / D ratio of each of the cellulose fibers in the molded article are determined by dissolving the resin component in the composition in an organic or inorganic solvent capable of dissolving the resin component of the composition, separating cellulose, After thoroughly washing with the solvent, an aqueous dispersion in which the solvent is replaced with pure water or a dispersible organic solvent is prepared, and the cellulose concentration is diluted with pure water to 0.1 to 0.5% by mass, It can be confirmed by casting on the top and air-dried as a measurement sample and measuring by the above-described measurement method. At this time, 100 or more randomly selected celluloses are measured.

  Examples of the modified cellulose in the present disclosure include those modified with one or more modifiers selected from an esterifying agent, a silylating agent, an isocyanate compound, a halogenated alkylating agent, an alkylene oxide and / or a glycidyl compound. No.

  The esterifying agent as a modifier includes an organic compound having at least one functional group capable of reacting with and esterifying a hydroxyl group on the surface of cellulose. Esterification can be carried out by the method described in paragraph [0108] of WO 2017/159823. The esterifying agent may be a commercially available reagent or product.

  Suitable examples of the esterifying agent are not particularly limited, but include, for example, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, Aliphatic monocarboxylic acids such as butyric acid; alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid; aromatics such as benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, and phenylacetic acid Monocarboxylic acids; and a plurality of mixtures arbitrarily selected from these, and symmetric anhydrides (acetic anhydride, maleic anhydride, cyclohexane-carboxylic anhydride, benzene-sulfonic anhydride) optionally selected therefrom, Mixed acid anhydride (butyric acid-valeric anhydride), cyclic anhydride (succinic anhydride, phthalic anhydride) Acid, naphthalene-1,8: 4,5-tetracarboxylic dianhydride, cyclohexane-1,2,3,4-tetracarboxylic acid 3,4-anhydride), ester anhydride (acetic acid 3- (ethoxy) Carbonyl) propanoic anhydride, benzoylethyl carbonate) and the like.

  Among them, from the viewpoint of reactivity, stability, price, etc., acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, benzoic acid, Acetic anhydride, maleic anhydride, succinic anhydride, and phthalic anhydride are preferably used.

  The silylating agent as a modifier includes a Si-containing compound having at least one reactive group capable of reacting with a hydroxyl group on the surface of cellulose or a group thereof after hydrolysis. The silylating agent may be a commercially available reagent or product.

  Preferred examples of the silylating agent are not particularly limited, but include chlorodimethylisopropylsilane, chlorodimethylbutylsilane, chlorodimethyloctylsilane, chlorodimethyldodecylsilane, chlorodimethyloctadecylsilane, chlorodimethylphenylsilane, and chloro (1-hexenyl). Dimethylsilane, dichlorohexylmethylsilane, dichloroheptylmethylsilane, trichlorooctylsilane, hexamethyldisilazane, 1,3-divinyl-1,1,3,3-tetramethyldisilazane, 1,3-divinyl-1,3 -Diphenyl-1,3-dimethyl-disilazane, 1,3-N-dioctyltetramethyl-disilazane, diisobutyltetramethyldisilazane, diethyltetramethyldisilazane, N-dipropyltetramethyldisilazane, N Dibutyltetramethyldisilazane or 1,3-di (para-t-butylphenethyl) tetramethyldisilazane, N-trimethylsilylacetamide, N-methyldiphenylsilylacetamide, N-triethylsilylacetamide, t-butyldiphenylmethoxysilane, octadecyl Examples thereof include dimethylmethoxysilane, dimethyloctylmethoxysilane, octylmethyldimethoxysilane, octyltrimethoxysilane, trimethylethoxysilane, and octyltriethoxysilane.

  Among these, hexamethyldisilazane, octadecyldimethylmethoxysilane, dimethyloctylmethoxysilane, and trimethylethoxysilane are preferably used from the viewpoints of reactivity, stability, and price.

  The halogenated alkylating agent as a modifying agent includes an organic compound having at least one functional group capable of reacting with a hydroxyl group on the surface of cellulose to halogenate and alkylate it. The halogenated alkylating agent may be a commercially available reagent or product.

  Suitable examples of the halogenated alkylating agent are not particularly limited, but chloropropane, chlorobutane, bromopropane, bromohexane, bromoheptane, iodomethane, iodoethane, iodooctane, iodooctadecane, iodobenzene and the like can be used. Among them, bromohexane and iodooctane can be preferably used in view of reactivity, stability, price and the like.

  The isocyanate compound as a modifier includes an organic compound having at least one isocyanate group capable of reacting with a hydroxyl group on the surface of cellulose. The isocyanate compound may be a blocked isocyanate compound capable of regenerating an isocyanate group by removing a blocking group at a specific temperature. And polymethylene polyphenyl polyisocyanate (polymeric MDI). These may be commercially available reagents or products.

  Preferred examples of the isocyanate compound include, but are not particularly limited to, aliphatic polyisocyanate, alicyclic polyisocyanate, aromatic polyisocyanate, araliphatic polyisocyanate, blocked isocyanate compound, polyisocyanate, and the like. For example, tetramethylene diisocyanate, dodecamethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3-bis (isocyanatemethyl) Cyclohexane), tolylene diisocyanate (TDI), 2,2'-diphenylmethane diisocyanate, 2,4'-diphenyl Nylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 4,4'-dibenzyl diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate) Dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, α, α, α, α-tetramethylxylylene diisocyanate, oxime-based blocking agents, phenol-based blocking agents, lactam-based blocking agents, alcohol-based blocking agents, active methylene Block reactant with an amine-based blocking agent, an amine-based blocking agent, a pyrazole-based blocking agent, a bisulfite-based blocking agent, or an imidazole-based blocking agent. And a cyanate compound.

  Among them, TDI, MDI, hexamethylene diisocyanate, and blocked isocyanate using a modified material of hexamethylene diisocyanate and hexamethylene diisocyanate as raw materials are preferably used from the viewpoints of reactivity, stability, and price.

  The upper limit of the dissociation temperature of the blocking group of the blocked isocyanate compound is preferably 210 ° C, more preferably 190 ° C, and still more preferably 150 ° C, from the viewpoint of reactivity and stability. The lower limit is preferably 70 ° C., more preferably 80 ° C., and even more preferably 110 ° C. Examples of the blocking agent having a dissociation temperature of the blocking group within this range include methyl ethyl ketone oxime, ortho-secondary butylphenol, caprolactam, sodium bisulfite, 3,5-dimethylpyrazole, 2-methylimidazole and the like.

  The alkylene oxide and / or glycidyl compound as a modifier includes an organic compound having at least one alkylene oxide group, glycidyl group and / or epoxy group capable of reacting with a hydroxyl group on the surface of cellulose. The alkylene oxide and / or glycidyl compound may be a commercially available reagent or product.

  Preferred examples of the alkylene oxide and / or glycidyl compound include, but are not particularly limited to, for example, methyl glycidyl ether, ethyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, 2-methyloctyl glycidyl ether, phenyl glycidyl ether, p Glycidyl ethers such as tertiary butyl phenyl glycidyl ether, sec-butyl phenyl glycidyl ether, n-butyl phenyl glycidyl ether, phenyl phenol glycidyl ether, cresyl glycidyl ether, dibromocresyl glycidyl ether; glycidyl acetate, glycidyl stearate and the like Glycidyl ester; ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether 1,4-butanediol diglycidyl ether, hexamethylene glycol diglycidyl ether, resorcinol diglycidyl ether, bisphenol A diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polybutylene glycol diglycidyl ether, glycerol Examples include polyhydric alcohol glycidyl ethers such as triglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, sorbitol polyglycidyl ether, sorbitan polyglycidyl ether, polyglycerol polyglycidyl ether, and diglycerol polyglycidyl ether.

  Among these, 2-methyloctyl glycidyl ether, hexamethylene glycol diglycidyl ether, and pentaerythritol tetraglycidyl ether are preferably used from the viewpoints of reactivity, stability, and price.

The modified cellulose nanofiber is obtained by dissolving the resin component in the composition in an organic or inorganic solvent capable of dissolving the resin component of the molded product, separating the cellulose by centrifugation or filtration of the solution, and sufficiently using the solvent. After the washing, the modified denatured cellulose nanofiber can be confirmed by subjecting it to thermal decomposition or hydrolysis. Alternatively, it can be confirmed by directly performing ¹ H-NMR and ¹³ C-NMR measurements.

  The blending amount of (B) cellulose nanofiber with respect to 100 parts by mass of (A) the thermoplastic resin is preferably 1 part by mass or more, and more preferably 3 parts by mass or more from the viewpoint of good mechanical properties, thermal stability and durability. And more preferably 5 parts by mass or more, and from the viewpoint of obtaining sufficient moldability, it is 200 parts by mass or less, preferably 100 parts by mass or less, more preferably 50 parts by mass or less.

<< (C) surface modifier >>
Next, the surface modifier (C) which can be used as an additional component in the present invention will be described in detail. In a typical embodiment, the (C) surface modifier is a low molecular weight thermoplastic and / or an amphipathic molecule. (C) The surface modifier may be a polymer having a different molecular weight, repeating structure, and / or block structure from (A) the thermoplastic resin. That is, the (C) surface modifier and the (A) thermoplastic resin may be the same polymer. In this case, when the respective number average molecular weights are compared, the smaller the molecular weight, the lower the (C) the surface modifier Becomes

  (C) The lower limit of the number average molecular weight of the surface modifier is preferably 100, more preferably 200, and most preferably 300. Further, the upper limit of the number average molecular weight is not particularly limited, but is preferably 50,000, more preferably 10,000 from the viewpoint of handleability. In order to secure good affinity with the cellulose nanofiber (B) having an average fiber diameter of 1000 nm or less, it is desirable that the number average molecular weight of the (C) surface modifier be within the above range.

  (C) The surface modifier may be used in the form of an aqueous dispersion or an aqueous solution, or may be a commercially available reagent or product.

  The preferred amount of (C) the surface modifier is within the range of (C) 50 parts by mass or less based on 100 parts by mass of the cellulose nanofiber (B) having an average fiber diameter of 1000 nm or less. is there. The upper limit is more preferably 45 parts by mass, even more preferably 40 parts by mass, still more preferably 35 parts by mass, and particularly preferably 30 parts by mass. The lower limit is not particularly limited, but is preferably 0.1 part by mass, more preferably 0.5 part by mass, and most preferably 1 part by mass with respect to 100 parts by mass of the cellulose nanofiber (B) having an average fiber diameter of 1000 nm or less. It is. By setting the upper limit of (C) the surface modifier as described above, the strength of (A) the thermoplastic resin can be kept good. In addition, by setting the lower limit of (C) the surface modifier to be as described above, the dispersibility of (A) cellulose nanofiber having an average fiber diameter of 1000 nm or less in (A) thermoplastic resin can be increased.

  Further, the method of adding the surface modifier (C) when preparing the resin composition to be a constituent material of the resin gear is not particularly limited, but (A) a thermoplastic resin, (B) an average fiber A method in which a cellulose nanofiber having a diameter of 1000 nm or less and (C) a surface modifier are mixed in advance and melt-kneaded, (A) a surface modifier is added in advance to a thermoplastic resin, and preliminary kneading is performed as necessary. After that, (B) a method of adding and melting and kneading cellulose nanofibers having an average fiber diameter of 1000 nm or less, and (B) a cellulose nanofiber having an average fiber diameter of 1000 nm or less and (C) a surface modifier (A) a method of melt-kneading with a thermoplastic resin after pre-mixing, (B) a dispersion in which cellulose nanofiber having an average fiber diameter of 1000 nm or less is dispersed in water, It was added Men'aratame modifying agent, after a cellulose formulation is dried, a method of adding the formulation (A) a thermoplastic resin, and the like are exemplified.

  (C) Specific examples of the low-molecular thermoplastic resin that can be suitably used as the surface modifier include polyamide resins, polyester resins, polyacetal resins, polycarbonate resins, polyacryl resins, and polyphenylene ether resins ( (Including modified polyphenylene ether modified by blending or graft-polymerizing polyphenylene ether with another resin), polyarylate resin, polysulfone resin, polyphenylene sulfide resin, polyethersulfone resin, polyketone resin, polyphenylene ether ketone Resin, polyimide resin, polyamideimide resin, polyetherimide resin, polyurethane resin (for example, thermoplastic polyurethane), polyolefin resin (for example, α-olefin copolymer), and various ionomers. It is.

  Preferred specific examples of the (C) surface modifier include high-density polyethylene, low-density polyethylene (for example, linear low-density polyethylene), polypropylene, polymethylpentene, cyclic olefins, poly1-butene, and poly1-pentene. , Polymethylpentene, ethylene / α-olefin copolymer, ethylene / butene copolymer, EPR (ethylene / propylene copolymer), modified ethylene / butene copolymer, EEA (ethylene / ethyl acrylate copolymer), Modified EEA, modified EPR, modified EPDM (ethylene-propylene-diene terpolymer), modified IR (isoprene rubber), modified SEBS (styrene-ethylene-butylene-styrene copolymer), halogenated isobutylene-paramethylstyrene Copolymer, ethylene-acrylic acid modified, ethylene- Acid vinyl copolymer and its acid modified product, copolymer of (ethylene and / or propylene) and (unsaturated carboxylic acid and / or unsaturated carboxylic acid ester), (ethylene and / or propylene) and (unsaturated Polyolefin obtained by metal salification of at least a part of the carboxyl group of the copolymer with carboxylic acid and / or unsaturated carboxylic acid ester), block copolymer of conjugated diene and vinyl aromatic hydrocarbon, conjugated diene and vinyl Hydrogenated block copolymers of aromatic hydrocarbons, copolymers of other conjugated diene compounds with non-conjugated olefins, natural rubber, various butadiene rubbers, various styrene-butadiene copolymer rubbers, isoprene rubber, butyl rubber, isobutylene Bromide, halogenated butyl rubber, acrylonitrilobutadiene Rubber, chloroprene rubber, ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, styrene-isoprene copolymer rubber, styrene-isoprene-butadiene copolymer rubber, isoprene-butadiene copolymer rubber, chloro Acrylonitrile based on acrylic or acrylonitrile such as sulfonated polyethylene, acrylic rubber, epichlorohydrin rubber, polysulfide rubber, silicone rubber, fluorine rubber, urethane rubber, polyvinyl chloride, polystyrene, polyacrylate, polymethacrylate, etc. Copolymer, acrylonitrile butanediene styrene (ABS) resin, acrylonitrile styrene (AS) resin, cellulose resin such as cellulose acetate, vinyl chloride / ethylene copolymer, vinyl chloride / vinegar Vinyl copolymer, an ethylene / vinyl acetate copolymer, and saponified ethylene / vinyl acetate copolymer,

  Polyethylene glycol, polypropylene glycol, poly (tetramethylene ether) glycol (PTMEG), poly (propylene oxide) glycol, polybutadiene diol and copolymers thereof (for example, a copolymer of propylene oxide and ethylene oxide, a copolymer of tetrahydrofuran and ethylene oxide) And these block copolymers. These may be used alone or in combination of two or more. When two or more kinds are used in combination, they may be used as a polymer alloy. Further, a resin obtained by modifying the above-described low-molecular thermoplastic resin with at least one compound selected from unsaturated carboxylic acids, acid anhydrides and derivatives thereof can also be used.

  Among these, from the viewpoints of heat resistance, moldability, design properties, and mechanical properties, polyolefin resins, polyamide resins, polyester resins, polyacetal resins, polyethylene glycol resins, polypropylene glycol resins, and the two types thereof The above-mentioned mixtures are preferred, and in particular, polyolefin-based resins, polyamide-based resins, polyester-based resins, polyethylene glycol-based resins, and polypropylene glycol-based resins are more preferred from the viewpoint of handling properties and costs.

A polyolefin-based resin that is preferable as the low-molecular thermoplastic resin is a polymer obtained by polymerizing a monomer unit containing an olefin (for example, an α-olefin). Specific examples of the polyolefin-based resin include, but are not particularly limited to, ethylene-based (co) weight exemplified by low-density polyethylene (for example, linear low-density polyethylene), high-density polyethylene, ultra-low-density polyethylene, and ultra-high-molecular-weight polyethylene. Coal, polypropylene, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, and other polypropylene-based (co) polymers, ethylene-acrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene And glycidyl methacrylate copolymers and other monomer units.
Here, the most preferable polyolefin-based resin includes polypropylene.

  Further, in order to increase the affinity with the cellulose nanofiber (B) having an average fiber diameter of 1000 nm or less, an acid-modified polyolefin resin can also be suitably used. The acid can be appropriately selected from maleic acid, fumaric acid, succinic acid, phthalic acid and anhydrides thereof, and polycarboxylic acids such as citric acid. Among these, maleic acid or its anhydride is preferred because of its high modification rate. The modification method is not particularly limited, but a method is generally used in which the resin is heated to a melting point or higher and melt-kneaded in the presence / absence of peroxide. As the polyolefin-based resin to be acid-modified, all of the above-mentioned polyolefin-based resins can be used, and polypropylene is particularly preferably used.

  The acid-modified polypropylene may be used alone, but it is more preferable to use it in combination with unmodified polypropylene in order to adjust the modification rate. At this time, the ratio of the acid-modified polypropylene to all the polypropylenes is preferably 0.5% by mass to 50% by mass. A more preferred lower limit is 1% by mass, further preferably 2% by mass, still more preferably 3% by mass, particularly preferably 4% by mass, and most preferably 5% by mass. Further, a more preferable upper limit is 45% by mass, further preferably 40% by mass, still more preferably 35% by mass, particularly preferably 30% by mass, and most preferably 20% by mass. (B) In order to maintain good interface strength with the cellulose nanofiber, the lower limit is preferably higher, and in order to maintain good ductility as a resin gear, the upper limit is preferable.

  The polyamide-based resin preferable as the low-molecular thermoplastic resin is not particularly limited, but includes polyamide 6, polyamide 11, polyamide 12, and the like obtained by a polycondensation reaction of lactams; 1,6-hexanediamine, 2-methyl-1, 5-pentanediamine, 1,7-heptanediamine, 2-methyl-1-6-hexanediamine, 1,8-octanediamine, 2-methyl-1,7-heptanediamine, 1,9-nonanediamine, 2-methyl Diamines such as -1,8-octanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, m-xylylenediamine, and butanediacid, pentanedioic acid, and hexanediamine; Acid, heptandioic acid, octanedioic acid, nonanedioic acid, decandioic acid, benzene-1,2-dicarboxylic acid, Polyamide 6, which is obtained as a copolymer with dicarboxylic acids such as cyclohexane-1,3-dicarboxylic acid and cyclohexane-1,4-dicarboxylic acid such as benzene-1,3-dicarboxylic acid and benzene-1,4 dicarboxylic acid. 6, polyamide 6,10, polyamide 6,11, polyamide 6,12, polyamide 6, T, polyamide 6, I, polyamide 9, T, polyamide 10, T, polyamide 2M5, T, polyamide MXD, 6, polyamide 6, C, polyamides 2M5, C, and the like; and copolymers of these copolymers (for example, polyamides 6, T / 6, I) and the like.

  Among these polyamide resins, aliphatic polyamides such as polyamide 6, polyamide 11, polyamide 12, polyamide 6,6, polyamide 6,10, polyamide 6,11 and polyamide 6,12, polyamide 6, C, polyamide 2M5, C The alicyclic polyamide is more preferable.

  There is no particular limitation on the terminal carboxyl group concentration of the polyamide resin that can be used as a low molecular thermoplastic resin, but the lower limit is preferably 20 μmol / g, more preferably 30 μmol / g. Further, the upper limit of the terminal carboxyl group concentration is preferably 150 μmol / g, more preferably 100 μmol / g, and still more preferably 80 μmol / g.

  In a polyamide as a low-molecular thermoplastic resin, the carboxyl end group ratio ([COOH] / [all end groups]) to all the end groups is more preferably 0.30 to 0.95. The lower limit of the carboxyl end group ratio is more preferably 0.35, even more preferably 0.40, and most preferably 0.45. The upper limit of the carboxyl terminal group ratio is more preferably 0.90, still more preferably 0.85, and most preferably 0.80. The carboxyl terminal group ratio is desirably 0.30 or more from the viewpoint of dispersibility of the (B) cellulose nanofiber in the composition, and 0.95 or less from the viewpoint of the color tone of the obtained composition. Is desirable.

  As a method for adjusting the terminal group concentration of the polyamide resin, a known method can be used. For example, a diamine compound, a monoamine compound, a dicarboxylic acid compound, a monocarboxylic acid compound, an acid anhydride, a monoisocyanate, a monoacid halide, a monoester, a monoalcohol, or the like may be used so that a predetermined end group concentration is obtained during polymerization of the polyamide. A method in which a terminal adjuster that reacts with a terminal group is added to the polymerization solution may be used.

  Examples of the terminal regulator that reacts with a terminal amino group include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, and isobutyric acid. Aliphatic monocarboxylic acids such as cyclohexane carboxylic acid; aromatic monocarboxylic acids such as benzoic acid, toluic acid, α-naphthalene carboxylic acid, β-naphthalene carboxylic acid, methyl naphthalene carboxylic acid, and phenyl acetic acid Carboxylic acids; and a plurality of mixtures arbitrarily selected from these. Among them, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid are preferred from the viewpoints of reactivity, sealed terminal stability, and price. And at least one terminal adjuster selected from the group consisting of benzoic acid and benzoic acid, and acetic acid is most preferable.

  Examples of a terminal adjuster that reacts with a terminal carboxyl group include aliphatic amines such as methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, and dibutylamine. Monoamines; alicyclic monoamines such as cyclohexylamine and dicyclohexylamine; aromatic monoamines such as aniline, toluidine, diphenylamine and naphthylamine, and any mixtures thereof. Among these, from the viewpoints of reactivity, boiling point, stability of the sealed terminal, and price, one or more selected from the group consisting of butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine, and aniline. Terminal modifiers are preferred.

The concentration of these amino terminal groups and carboxyl terminal groups is preferably determined from the integrated value of the characteristic signal corresponding to each terminal group by ¹ H-NMR from the viewpoint of accuracy and simplicity. As a method for determining the concentration of these terminal groups, a method described in JP-A-7-228775 is specifically recommended. When this method is used, deuterated trifluoroacetic acid is useful as a measuring solvent. In addition, the number of integrations of ¹ H-NMR requires at least 300 scans even when measurement is performed with an instrument having a sufficient resolution. In addition, the concentration of the terminal group can be measured by a titration measurement method as described in JP-A-2003-055549. However, quantification by ¹ H-NMR is more preferable in order to minimize the influence of mixed additives, lubricants and the like.

The polyester-based resin which is preferable as the thermoplastic resin is not particularly limited, but includes polyethylene terephthalate (PET), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), polybutylene adipate terephthalate (PBAT), polyarylate ( One or more selected from PAR), polyhydroxyalkanoic acid (PHA, polylactic acid (PLA), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polycarbonate (PC) and the like can be used.
Among these, more preferred polyester-based resins include PET, PBS, PBSA, PBT, and PEN, and more preferably, PBS, PBSA, and PBT.

  Further, the polyester resin, the terminal group can be freely changed depending on the monomer ratio at the time of polymerization and the presence or absence and the amount of the terminal stabilizer, but the ratio of the carboxyl terminal group to the total terminal group of the polyester resin. ([COOH] / [all terminal groups]) is preferably 0.30 to 0.95. The lower limit of the carboxyl terminal group ratio is more preferably 0.35, further preferably 0.40, and most preferably 0.45. The upper limit of the carboxyl terminal group ratio is more preferably 0.90, further preferably 0.85, and most preferably 0.80. The carboxyl terminal group ratio is desirably 0.30 or more from the viewpoint of dispersibility of the (B) cellulose nanofiber in the composition, and 0.95 or less from the viewpoint of the color tone of the obtained composition. Is desirable.

  Polyacetal resins preferred as thermoplastic resins include homopolyacetals using formaldehyde as a raw material and copolyacetals containing trioxane as a main monomer and, for example, 1,3-dioxolane as a comonomer component, and both are usable. However, from the viewpoint of thermal stability during processing, copolyacetal can be preferably used. Particularly, the amount of the comonomer component (for example, 1,3-dioxolane) is preferably in the range of 0.01 to 4 mol%. A more preferred lower limit of the comonomer component amount is 0.05 mol%, further preferably 0.1 mol%, and particularly preferably 0.2 mol%. A more preferred upper limit is 3.5 mol%, still more preferably 3.0 mol%, particularly preferably 2.5 mol%, and most preferably 2.3 mol%.

  From the viewpoint of thermal stability during extrusion and molding, the lower limit is preferably within the above range, and from the viewpoint of mechanical strength, the upper limit is preferably within the above range.

Next, (C) an amphipathic molecule that can be used as a surface modifier will be described in detail.
In a typical embodiment, the amphiphilic molecule has a dynamic surface tension of 60 mN / m or less. Examples of the amphiphilic molecule include those having a carbon atom as a basic skeleton and having a functional group composed of an element selected from carbon, hydrogen, oxygen, nitrogen, chlorine, sulfur, and phosphorus. As long as the molecule has the above-mentioned structure, a compound in which an inorganic compound and the above functional group are chemically bonded is also preferable. The amphiphilic molecule may be a commercially available reagent or product.

  The amphipathic molecule may be used alone or as a mixture of two or more amphipathic molecules. In the case of a mixture, the characteristic values (eg, static surface tension, dynamic surface tension, SP value) of the amphipathic molecules of the present disclosure refer to the values of the mixture.

  In the present embodiment, it is preferable that the static surface tension of the amphiphilic molecule is 20 mN / m or more. This static surface tension refers to the surface tension measured by the Wilhelmy method. When a liquid amphiphilic molecule is used at room temperature, the value measured at 25 ° C. is used. When a solid or semi-solid amphipathic molecule is used at room temperature, the amphipathic molecule is heated to a temperature equal to or higher than the melting point and measured in a molten state. In the present disclosure, room temperature means 25 ° C. For the purpose of facilitating the addition, the amphiphilic molecule may be dissolved and diluted in an organic solvent, water, or the like. The above-mentioned static surface tension in this case means the static surface tension of the amphipathic molecule used.

  The fact that the static surface tension of the amphipathic molecule is within the specific range of the present disclosure means that (B) the dispersibility of the cellulose nanofiber having an average fiber diameter of 1000 nm or less in a resin is remarkably improved. It works. Although the reason is not clear, the hydrophilic functional group in the amphipathic molecule is (B) through a hydrogen bond or the like with a hydroxyl group or a reactive group on the surface of the cellulose nanofiber having an average fiber diameter of 1000 nm or less. It is considered that (B) coats the surface of the cellulose nanofiber having an average fiber diameter of 1000 nm or less and inhibits the formation of the interface with the resin. It is considered that the hydrophilic group is disposed on the cellulose nanofiber side (B) having an average fiber diameter of 1000 nm or less, so that the resin side has a hydrophobic atmosphere and the affinity with the resin side is also increased.

  The preferred lower limit of the static surface tension of the amphiphilic molecule is 23 mN / m, more preferably 25 mN / m, still more preferably 30 mN / m, still more preferably 35 mN / m, and most preferably 39 mN / m. . (E) A preferred upper limit of the static surface tension of the surfactant is 72.8 mN / m, more preferably 60 mN / m, still more preferably 50 mN / m, and most preferably 45 mN / m.

  Cellulose having both an affinity for the amphipathic molecule for the thermoplastic resin and (B) an affinity for the cellulose nanofiber having an average fiber diameter of 1000 nm or less, and having (B) an average fiber diameter of 1000 nm or less in the resin. It is preferable that the static surface tension of the amphipathic molecule be in a specific range from the viewpoint of exhibiting characteristics such as fine dispersion of the nanofiber, fluidity of the resin composition, and improvement in strength and elongation of the resin molded product.

The static surface tension of the amphipathic molecule referred to in the present disclosure can be measured by using a commercially available surface tension measuring device. As a specific example, it can be measured by the Wilhelmy method using an automatic surface tension measuring device (for example, a product name “CBVP-Z” manufactured by Kyowa Interface Science Co., Ltd., using an attached glass cell). At this time, when the surfactant (E) is a liquid at room temperature, the height from the bottom to the liquid surface was set to 7 mm to 9 mm in the attached stainless steel dish, and the temperature was adjusted to 25 ° C. ± 1 ° C. It is measured later and determined by the following equation.
γ = (P-mg + shρg) / Lcos θ
Here, γ: static surface tension, P: balancing force, m: plate mass, g: gravitational constant, L: plate peripheral length, θ: contact angle between plate and liquid, s: plate cross-sectional area, h: ( The depth submerged from the liquid surface (until the force balances), ρ: the density of the liquid.

  Since the surface tension of a solid at room temperature cannot be measured by the above method, the surface tension measured at a temperature of melting point + 5 ° C. is adopted for convenience. When the melting point is an unknown substance, first, the melting point is measured by a visual melting point measurement method (JIS K6220), heated to a temperature equal to or higher than the melting point, and then adjusted to a temperature of the melting point + 5 ° C. This is possible by measuring the surface tension.

  The dynamic surface tension of the amphiphilic molecule is preferably 60 mN / m or less. The more preferable upper limit of the dynamic surface tension is 55 mN / m, more preferably 50 mN / m, still more preferably 45 mN / m, and particularly preferably 40 mN / m. (E) A preferred lower limit of the dynamic surface tension of the surfactant is 10 mN / m. A more preferred lower limit is 15 mN / m, most preferably 20 mN / m.

The dynamic surface tension referred to here is the maximum bubble pressure method (measured the maximum pressure (maximum bubble pressure) when bubbles are generated by flowing air through a thin tube (hereinafter referred to as a probe) inserted into a liquid, Is a method of calculating the surface tension. Specifically, (E) a surfactant is dissolved or dispersed in ion-exchanged water with 5% by mass of a surfactant to prepare a measurement solution. After the temperature is adjusted to 25 ° C., a dynamic surface tensiometer (for example, manufactured by Eiko Seiki Co., Ltd.) The product name refers to the value of the surface tension measured using a Theta Science t-60 model, a probe (capillary TYPE I (manufactured by Peak Resin), single mode) and a bubble generation cycle of 10 Hz. Is determined by the following equation.
σ = ΔP · r / 2
Here, σ: dynamic surface tension, ΔP: pressure difference (maximum pressure−minimum pressure), r: capillary radius.

  Dynamic surface tension, as measured by the maximum bubble pressure method, refers to the dynamic surface tension of a surfactant in a fast moving field. In water, amphiphilic molecules usually form micelles. Low dynamic surface tension means that the diffusion rate of the surfactant molecule from the micelle state is high, and high dynamic surface tension means that the diffusion rate of the molecule is low.

  The fact that the dynamic surface tension of the amphiphilic molecule is equal to or less than the specific value has an effect of (B) remarkably improving the dispersion of the cellulose nanofiber having an average fiber diameter of 1000 nm or less in the resin composition. Is advantageous. Although the details of the reason for the improvement of the dispersibility are unknown, amphiphilic molecules having a low dynamic surface tension are excellent in diffusivity in an extruder, and thus, (B) cellulose nano-particles having an average fiber diameter of 1000 nm or less. It is considered that localization at the interface between the fiber and the resin and that (B) the surface of the cellulose nanofiber having an average fiber diameter of 1000 nm or less can be satisfactorily coated contribute to the effect of improving dispersibility. The effect of improving the dispersibility of the cellulose nanofiber having an average fiber diameter of 1,000 nm or less (B) obtained by setting the dynamic surface tension of the surfactant to a specific value or less is that the strength defect of the molded article is eliminated. Produce a remarkable effect.

  As the amphiphilic molecule, those having a higher boiling point than water are preferable. Note that the boiling point higher than that of water refers to a boiling point higher than the boiling point at each pressure in the water vapor pressure curve (for example, 100 ° C. under one atmosphere).

  By selecting an amphipathic molecule having a higher boiling point than water, for example, (E) cellulose nanofiber dispersed in water in the presence of a surfactant and (B) having an average fiber diameter of 1000 nm or less can be obtained. Is dried to obtain (B) a cellulose nanofiber preparation having an average fiber diameter of 1000 nm or less. In the process of evaporating water, water and amphipathic molecules are substituted, and (B) the average fiber diameter is 1000 nm or less. Since the amphipathic molecules are present on the surface of the cellulose nanofiber, the effect of (B) significantly suppressing aggregation of the cellulose nanofiber having an average fiber diameter of 1000 nm or less can be achieved.

  The amphipathic molecule is preferably a liquid at room temperature (that is, 25 ° C.) from the viewpoint of its handleability. Amphiphilic molecules that are liquid at room temperature have the advantage that they are easily compatible with (B) cellulose nanofibers having an average fiber diameter of 1000 nm or less and easily penetrate into resins.

  As the amphipathic molecule, those having a solubility parameter (SP value) of 7.25 or more can be more preferably used. When the amphiphilic molecule has the SP value in this range, the dispersibility of the (B) cellulose nanofiber having an average fiber diameter of 1000 nm or less in the resin is improved.

The SP value is dependent on both the cohesive energy density and the molar molecular weight of a substance according to the Fosters literature (RF Fenders: Polymer Engineering & Science, vol. 12 (10), p. 2359-2370 (1974)). However, these are considered to depend on the type and number of substituents of the substance, and according to Ueda et al.'S literature (Paint Research, No. 152, Oct. 2010), the existing ones described in Examples described later are used. SP values (cal / cm ³ ) ^1/2 for major solvents have been published.

  The SP value of the amphiphilic molecule can be experimentally determined from the boundary between soluble and insoluble when the amphiphilic molecule is dissolved in various solvents having known SP values. For example, when 1 mL of an amphipathic molecule is dissolved in various solvents (10 mL) having different SP values in the table shown in the examples for 1 hour at room temperature under stirring with a stirrer, it can be determined whether or not the entire amount is dissolved. is there. For example, when the amphipathic molecule is soluble in diethyl ether, the SP value of the amphipathic molecule is 7.25 or more.

  In one aspect, the amphiphilic molecule is a surfactant. Examples of the surfactant include a compound having a chemical structure in which a hydrophilic substituent and a hydrophobic substituent are covalently bonded, and those used in various applications such as food and industrial use can be used. For example, the following may be used alone or in combination of two or more. In a particularly preferred embodiment, the surfactant is a surfactant having a specific dynamic surface tension as described above.

  As the surfactant, any of anionic surfactants, nonionic surfactants, amphoteric surfactants, and cationic surfactants can be used. In terms of affinity, an anionic surfactant and a nonionic surfactant are preferred, and a nonionic surfactant is more preferred.

  Examples of the anionic surfactant include fatty acid sodium (fatty acid), sodium fatty acid potassium, and sodium alpha sulfo fatty acid ester as fatty acid (anion), and linear sodium alkylbenzene sulfonate as linear alkylbenzene based. Alcohols (anions) include sodium alkyl sulfates, sodium alkyl ether sulfates, and the like. Alpha-olefins include sodium alpha-olefin sulfonates, and normal paraffins include sodium alkyl sulfonates. It is also possible to use one kind or a mixture of two or more kinds.

  Examples of the nonionic surfactant include fatty acid-based (nonionic) glycolipids such as sucrose fatty acid esters, sorbitan fatty acid esters, and polyoxyethylene sorbitan fatty acid esters, and fatty acid alkanolamides. Examples of the (ion) include polyoxyethylene alkyl ethers, and examples of the alkylphenol-based compound include polyoxyethylene alkyl phenyl ether. These may be used alone or in combination of two or more.

  Examples of the amphoteric surfactant include an amino acid surfactant such as sodium alkylaminofatty acid, a betaine surfactant such as alkyl betaine, and an amine oxide surfactant such as an alkylamine oxide. It is also possible to use a mixture of more than one species.

  Examples of the cationic surfactant include quaternary ammonium salts, such as alkyltrimethylammonium salts and dialkyldimethylammonium salts. These can be used alone or in combination of two or more. .

  The surfactant may be a derivative of a fat. Fats and oils include esters of fatty acids and glycerin, usually those in the form of triglyceride (tri-O-acylglycerin). Dry oils, semi-dry oils, classified as non-drying oils in order of being easily solidified by oxidation with fatty oils, edible, those used for various purposes such as industrial use, for example, the following, One or two or more of them are used in combination.

  Examples of fats and oils include animal and vegetable oils such as terpin oil, tall oil, rosin, white squeezed oil, corn oil, soybean oil, sesame oil, rapeseed oil (canola oil), rice oil, bran oil, camellia oil, safflower oil (safflower oil) , Palm oil (palm kernel oil), cottonseed oil, sunflower oil, perilla oil (EB oil), linseed oil, olive oil, peanut oil, almond oil, avocado oil, hazelnut oil, walnut oil, grape seed oil, mustard oil, Lettuce oil, fish oil, whale oil, shark oil, liver oil, cocoa butter, peanut butter, palm oil, lard (pork tallow), het (tallow fat), chicken oil, rabbit fat, sheep fat, horse fat, schmaltz, milk fat (butter, Grease, etc.), hardened oils (margarine, shortening, etc.), castor oil (vegetable oil) and the like.

  In particular, among the above-mentioned animal and vegetable oils, terpin oil, tall oil, and rosin are preferable from the viewpoint of (B) affinity to the cellulose nanofiber surface and uniform coating properties.

  Terpine oil (also referred to as terbin oil) is an essential oil obtained by steam distillation of pine tree chips or pine resin obtained from those trees, and both pine essential oil and turpentine Say. Examples of the terpin oil include gum turpentine oil (obtained by steam distillation of pine resin), wood turpentine oil (obtained by steam distillation or carbonization of pine tree chips), turpentine sulfate Oil (obtained by distilling chips when heat-treated during sulphate pulp production) and turpentine sulphite oil (extracted by heating chips during sulphite pulp production), almost colorless To a pale yellow liquid, mainly composed of α-pinene and β-pinene except for turpentine sulfite oil. Turpentine sulfite oil, unlike other turpentine oils, contains p-cymene as a main component. If the above-mentioned components are contained, derivatives of any one or a plurality of mixtures contained in the terpin oil can be used as the surfactant of the present invention.

  Tall oil is an oil composed mainly of resins and fatty acids, which is a by-product of making kraft pulp from pine wood. As the tall oil, a tall fat containing oleic acid and linoleic acid as main components, or a tall rosin containing a diterpenoid compound having 20 carbon atoms such as abietic acid as a main component may be used.

  Rosin is a residue that remains after collecting balsams such as rosin, which is the sap of pine family plants, and distilling turpentine essential oil. Rosin is a natural resin mainly composed of rosin acid (abietic acid, parastolic acid, isopimaric acid, etc.). It is. Also called colophony or colophonium. Among them, tall rosin, wood rosin, and gum rosin can be suitably used. Rosin derivatives obtained by subjecting these rosins to various stabilization treatments, esterification treatments, purification treatments and the like can be used as surfactants. The stabilization treatment means that the rosin is subjected to hydrogenation, disproportionation, dehydrogenation, polymerization treatment and the like. Further, the esterification treatment refers to a treatment in which the rosin or the rosin subjected to the stabilization treatment is reacted with various alcohols to form a rosin ester. Various known alcohols or epoxy compounds can be used for the production of the rosin ester. Examples of the alcohol include monohydric alcohols such as n-octyl alcohol, 2-ethylhexyl alcohol, decyl alcohol, and lauryl alcohol; dihydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and neopentyl glycol; Trihydric alcohols such as glycerin, trimethylolethane, trimethylolpropane, and cyclohexanedimethanol; and tetrahydric alcohols such as pentaerythritol and diglycerin. Also, isopentyldiol, ethylhexanediol, erythrulose, ozonized glycerin, caprylyl glycol, glycol, (C15-18) glycol, (C20-30) glycol, glycerin, diethylene glycol, diglycerin, dithiaoctanediol, DPG, Thioglycerin, 1,10-decanediol, decylene glycol, triethylene glycol, thimethylmethylhydroxymethylcyclohexanol, phytantriol, phenoxypropanediol, 1,2-butanediol, 2,3-butanediol, butylethyl Polyvalent such as propanediol, BG, PG, 1,2-hexanediol, hexylene glycol, pentylene glycol, methylpropanediol, menthanediol, lauryl glycol Alcohol may be used. In addition, those classified as sugar alcohols such as inositol, erythritol, xylitol, sorbitol, maltitol, mannitol, and lactitol are also included in the polyhydric alcohol.

  Further, as the alcohol, an alcoholic water-soluble polymer can be used. As alcoholic water-soluble polymers, polysaccharides / mucopolysaccharides, those classified as starch, those classified as polysaccharide derivatives, those classified as natural resins, those classified as cellulose and derivatives, proteins -Those classified as peptides, those classified as peptide derivatives, those classified as synthetic homopolymers, those classified as acrylic (methacrylic acid) acid copolymers, those classified as urethane polymers, Examples include those classified as laminates, those classified as cationized polymers, and those classified as other synthetic polymers, and water-soluble ones at room temperature can be used. More specifically, sodium polyacrylate, cellulose ether, calcium alginate, carboxyvinyl polymer, ethylene / acrylic acid copolymer, vinylpyrrolidone-based polymer, vinyl alcohol / vinylpyrrolidone copolymer, nitrogen-substituted acrylamide-based polymer, poly Cationic polymers such as acrylamide, cationized guar gum, dimethylacrylammonium polymer, acrylic acid methacrylate acrylic copolymer, POE / POP copolymer, polyvinyl alcohol, pullulan, agar, gelatin, tamarind seed polysaccharide, xanthan gum, carrageenan , High methoxyl pectin, low methoxyl pectin, guar gum, gum arabic, cellulose whiskers, arabinogalactan, karaya gum, tragacanth gum, algin , Albumin, casein, curdlan, gellan gum, dextran, cellulose (those not cellulose fibers and cellulose whiskers of the present disclosure), polyethylene imine, polyethylene glycol, cationized silicone polymer and the like.

  Among the various rosin esters described above, (B) those in which rosin and a water-soluble polymer are esterified because the coating properties of the cellulose nanofiber surface and the dispersibility of the cellulose preparation in the resin tend to be further promoted. Esterified products of rosin and polyethylene glycol (also referred to as rosin ethylene oxide adduct, polyoxyethylene glycol resin acid ester, and polyoxyethylene rosin acid ester) are particularly preferable.

  As the hardened castor oil type surfactant, for example, hydrogenated castor oil (castor oil, castor oil, castor oil) which is a kind of vegetable oil collected from the seeds of castor seeds of the family Euphorbiaceae is used as a raw material. Is a hydrophobic group, and a hydroxyl group in the structure thereof and a hydrophilic group such as a PEO chain are covalently bonded. The components of castor oil are glycerides of unsaturated fatty acids (87% ricinoleic acid, 7% oleic acid, 3% linoleic acid) and small amounts of saturated fatty acids (3% palmitic acid, stearic acid, etc.). In addition, typical POE group structures include those having 4 to 40 ethylene oxide (EO) residues, and typical examples include those having 15 to 30 ethylene oxide (EO) residues. The EO residue of nonylphenol ethoxylate is preferably 15 to 30, more preferably 15 to 25, and particularly preferably 15 to 20.

  Examples of the mineral oil derivatives include greases such as calcium soap-based grease, calcium composite soap-based grease, sodium soap-based grease, aluminum soap-based grease, and lithium soap-based grease.

  The surfactant may be an alkylphenyl type compound, for example, an alkylphenol ethoxylate, that is, a compound obtained by ethoxylating an alkylphenol with ethylene oxide. Alkylphenol ethoxylates are nonionic surfactants. Since a hydrophilic polyoxyethylene (POE) chain and a hydrophobic alkylphenol group are linked by an ether bond, it is also called a poly (oxyethylene) alkylphenyl ether. Generally, a series of products having different average chain lengths are commercially available as a mixture of a large number of compounds having different alkyl chain lengths and POE chain lengths. The alkyl chain length is commercially available having a carbon number of 6 to 12 (excluding the phenyl group), but typical alkyl group structures include nonylphenol ethoxylate and octylphenol ethoxylate. In addition, typical POE group structures include those having 5 to 40 ethylene oxide (EO) residues, and typical examples include those having 15 to 30 ethylene oxide (EO) residues. The EO residue of nonylphenol ethoxylate is preferably 15 to 30, more preferably 15 to 25, and particularly preferably 15 to 20.

  The surfactant may be a β-naphthyl-type compound. For example, a β-monosubstituted compound in which naphthalene is contained in a part of its chemical structure and carbon at the 2 or 3 or 6 or 7 position of the aromatic ring is bonded to a hydroxyl group. Compounds in which a body and a hydrophilic group such as a PEO chain are covalently bonded. In addition, typical POE group structures include those having 4 to 40 ethylene oxide (EO) residues, and typical examples include those having 15 to 30 ethylene oxide (EO) residues. The EO residue is preferably 15 to 30, more preferably 15 to 25, and particularly preferably 15 to 20.

The surfactant may be a bisphenol A-type compound. For example, the surfactant may include bisphenol A (chemical formula: (CH ₃ ) ₂ C (C ₆ H ₄ OH) ₂ ) in a part of its chemical structure. A compound in which two phenol groups in the inside and a hydrophilic group such as a PEO chain are covalently bonded. In addition, typical POE group structures include those having 4 to 40 ethylene oxide (EO) residues, and typical examples include those having 15 to 30 ethylene oxide (EO) residues. The EO residue of nonylphenol ethoxylate is preferably 15 to 30, more preferably 15 to 25, and particularly preferably 15 to 20. This EO residue indicates an average value obtained by adding two ether bonds when one molecule has two ether bonds.

  The surfactant may be a styrenated phenyl type compound. For example, a styrenated phenyl group is included in a part of its chemical structure, and a phenol group in the structure and a hydrophilic group such as a PEO chain are covalently bonded. Compounds described above can be mentioned. The styrenated phenyl group has a structure in which one to three molecules of styrene are added to the benzene ring of a phenol residue. In addition, typical POE group structures include those having 4 to 40 ethylene oxide (EO) residues, and typical examples include those having 15 to 30 ethylene oxide (EO) residues. The EO residue of nonylphenol ethoxylate is preferably 15 to 30, more preferably 15 to 25, and particularly preferably 15 to 20. This EO residue indicates an average value obtained by adding two ether bonds when one molecule has two ether bonds.

  Specific preferred examples of the surfactant include, for example, acyl amino acid salts such as acyl gutamate, higher alkyl sulfates such as sodium laurate, sodium palmitate, sodium lauryl sulfate, potassium lauryl sulfate, and polyoxyethylene lauryl. Anionic surfactants such as alkyl ether sulfates such as triethanolamine sulfate and sodium polyoxyethylene lauryl sulfate; N-acyl sarcosinates such as sodium lauroyl sarcosine; alkyls such as stearyltrimethylammonium chloride and lauryltrimethylammonium chloride Trimethylammonium salt, distearyldimethylammonium dialkyldimethylammonium chloride, (N, N'-dimethyl-3,5-methylenepiperidinium chloride), Cationic surfactants such as alkylpyridinium salts such as pitidinium, alkyl quaternary ammonium salts, alkylamine salts such as polyoxyethylene alkylamine, polyamine fatty acid derivatives, and amyl alcohol fatty acid derivatives; 2-undecyl-N, N, N- (Hydroxyethyl carboxymethyl) 2-imidazoline sodium, 2-cocoyl-2-imitazolinium hydroxide-1-carboxyethyloxy disodium salt and other imidazoline amphoteric surfactants, 2-heptadecyl-N-carboxymethyl- Amphoteric surfactants such as betaine-based amphoteric surfactants such as N-hydroxyethylimidazolinium betaine, betaine lauryldimethylaminoacetate, betaine, alkylbetaine, amidobetaine and sulfobetaine, sorbitan nomooleate, and sorbie Monomoisostearate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan sesquioleate, sorbitan trioleate, diglycerol penta-2-ethylhexylate sorbitan, diglycerol tetra-2-ethylhexylate sorbitan, etc. Sorbitan fatty acid esters, glycerin monostearate, glycerin polyglycerin fatty acids such as α, α'-oleic acid pyroglutamate, glyceryl monostearate, propylene glycol fatty acid esters such as propylene glycol monostearate, curing Castor oil derivative, glycerin alkyl ether, polyoxyethylene-sorbitan monostearate, polyoxyethylene-sorbitan monooleate Polyoxyethylene-sorbitan fatty acid esters such as polyoxyethylene-sorbitan tetraoleate, polyoxyethylene-sorbit monolaurate, polyoxyethylene-sorbit monooleate, polyoxyethylene-sorbit pentaoleate, polyoxyethylene- Polyoxyethylene-glycerin fatty acid esters such as sorbit monostearate, polyoxyethylene-glycerin monoisostearate, polyoxyethylene-glycerin triisostearate, polyoxyethylene monooleate, polyoxyethylene distearate, poly Polyoxyethylene fatty acid esters such as oxyethylene monodioleate and ethylene glycol cysteate, polyoxyethylene hydrogenated castor oil, polyoxyethylene Castor oil, polyoxyethylene hydrogenated castor oil monoisostearate, polyoxyethylene hydrogenated castor oil triisostearate, polyoxyethylene hydrogenated castor oil monopyroglutamic acid monoisostearate diester, polyoxyethylene hydrogenated castor oil maleic acid, etc. Nonionic surfactants such as oxyethylene castor oil-hardened castor oil derivatives and the like are included.

  Among them, (B) a surfactant having a polyoxyethylene chain, a carboxylic acid, or a hydroxyl group as a hydrophilic group is preferable from the viewpoint of affinity with the cellulose nanofiber, and a polyoxyethylene having a polyoxyethylene chain as a hydrophilic group. Ethylene-based surfactants (polyoxyethylene derivatives) are more preferred, and nonionic polyoxyethylene derivatives are even more preferred. The polyoxyethylene chain length of the polyoxyethylene derivative is preferably 3 or more, more preferably 5 or more, still more preferably 10 or more, and particularly preferably 15 or more. The longer the chain length, the higher the affinity with (B) cellulose nanofibers, but the balance with coating properties (localization at the interface with (A) thermoplastic resin and (B) cellulose nanofibers) In the formula, the upper limit is preferably 60 or less, more preferably 50 or less, still more preferably 40 or less, particularly preferably 30 or less, and most preferably 20 or less.

  When (B) cellulose nanofiber is blended with a hydrophobic resin (for example, polyolefin, polyphenylene ether, or the like), it is preferable to use a hydrophilic group having a polyoxypropylene chain instead of a polyoxyethylene chain. The polyoxypropylene chain length is preferably 3 or more, more preferably 5 or more, still more preferably 10 or more, and particularly preferably 15 or more. The longer the chain length, the higher the affinity for (B) cellulose nanofibers, but in terms of balance with coating properties, the upper limit is preferably 60 or less, more preferably 50 or less, still more preferably 40 or less, and 30 or less. The following is particularly preferred, and 20 or less is most preferred.

  Among the above-mentioned surfactants, particularly, as the hydrophobic group, alkyl ether type, alkyl phenyl ether type, rosin ester type, bisphenol A type, β naphthyl type, styrenated phenyl type, and hydrogenated castor oil type have affinity for resin. , So that it can be suitably used. The preferred alkyl chain length (in the case of alkylphenyl, the number of carbon atoms excluding the phenyl group) is preferably 5 or more, more preferably 10 or more, still more preferably 12 or more, and particularly preferably 16 or more. . When the resin is a polyolefin, the upper limit is not set because the affinity with the resin increases as the number of carbon atoms increases, but the upper limit is preferably 30, and more preferably 25.

  Among these hydrophobic groups, those having a cyclic structure or those having a bulky multifunctional structure are preferable, and those having a cyclic structure include alkylphenyl ether type, rosin ester type, bisphenol A type, β naphthyl type, The styrenated phenyl type is preferred, and the cured castor oil type is particularly preferred as having a polyfunctional structure. Among these, rosin ester type and hardened castor oil type are most preferable.

  Therefore, in a particularly preferred embodiment, the surfactant is at least one selected from the group consisting of rosin derivatives, alkylphenyl derivatives, bisphenol A derivatives, β-naphthyl derivatives, styrenated phenyl derivatives, and hydrogenated castor oil derivatives.

<< (D) metal ion component >>
Next, the metal ion component (D) that can be used in the present invention will be described in detail.
The resin gear can include (D) a metal ion component as an additional component. (D) The metal ion component may be a commercially available reagent or product.

  (D) Examples of the metal ion component include a copper compound, a halide of a metal (other than copper or copper), an alkali metal salt, and an alkaline earth metal salt.

  The upper limit of the content of the metal ion component (D) in the resin gear of the present embodiment is preferably 5 parts by mass, and more preferably 2 parts by mass based on 100 parts by mass of the thermoplastic resin (A). Is more preferable, and the amount is more preferably 0.5 part by mass. (D) The lower limit of the content of the metal ion component is preferably 0.005 parts by mass, more preferably 0.01 part by mass, based on 100 parts by mass of the thermoplastic resin (A). More preferably, it is 0.015 parts by mass. Surprisingly, when the amount of the metal ion component (D) is within the above range, the wear resistance of the resin gear in a sliding test is improved. Although the cause of such excellent abrasion resistance is unknown, it is not clear yet, but (B) the interface between the surface of the cellulose nanofiber and (C) the surface modifier, or (B) the surface of the cellulose nanofiber and (A) the heat It is presumed that the metal ion component (D) is present at the interface with the plastic resin, thereby increasing the adhesion.

Examples of the copper compound include, but are not limited to, copper halides such as copper chloride, copper bromide, and copper iodide; copper acetate, copper propionate, copper benzoate, copper adipate, copper terephthalate Carboxylic acid copper salts such as copper isophthalate, copper salicylate, copper nicotinate, and copper stearate; copper complex salts in which copper is coordinated with a chelating agent such as ethylenediamine and ethylenediaminetetraacetic acid; One type of copper compound may be used, or two or more types may be used in combination. As the copper compound, copper iodide (CuI) is preferred from the viewpoints of being more excellent in heat aging resistance and being capable of suppressing metal corrosion (hereinafter, also simply referred to as “metal corrosion”) of a screw or a cylinder portion during molding extrusion. , cuprous bromide (CuBr), cupric bromide (CuBr _2), cuprous chloride (CuCl), and copper acetate are preferred, copper iodide, and copper acetate is more preferred.

  The upper limit of the content of the copper compound is preferably 0.6 parts by mass, more preferably 0.4 parts by mass, and more preferably 0.3 parts by mass, based on 100 parts by mass of the thermoplastic resin (A). Is more preferable. The lower limit of the content of the copper compound is preferably 0.005 parts by mass, more preferably 0.01 parts by mass, and more preferably 0.015 parts by mass, per 100 parts by mass of the thermoplastic resin (A). Is more preferable. When the lower limit of the content of the copper compound is within the above range, the heat aging resistance is further improved. When the upper limit of the content of the copper compound is within the above range, copper precipitation and metal corrosion can be further suppressed.

  The resin gear of the present embodiment may further contain at least one metal halide selected from the group consisting of an alkali metal halide and an alkaline earth metal halide. One metal halide may be used alone, or two or more metal halides may be used in combination.

  Examples of the metal halide include, but are not limited to, potassium iodide, potassium bromide, potassium chloride, sodium iodide, and sodium chloride. As the metal halide, potassium iodide and potassium bromide are preferable, and potassium iodide is more preferable, in that the heat aging resistance of the resin composition is further improved and metal corrosion is further suppressed.

  The upper limit of the content of the metal halide in the resin gear is preferably 0.6 parts by mass, more preferably 0.4 parts by mass, based on 100 parts by mass of the thermoplastic resin (A). , 0.3 parts by mass. The lower limit of the content of the metal halide in the resin gear is preferably 0.005 parts by mass, more preferably 0.01 part by mass, based on 100 parts by mass of the thermoplastic resin (A). , 0.015 parts by mass. When the lower limit of the content of the metal halide is within the above range, the heat aging resistance is further improved. When the upper limit of the content of the metal halide is within the above range, copper precipitation and metal corrosion can be further suppressed.

  The metal halide is preferably blended such that the molar ratio C3 / C4 of the content C3 of the halogen element and the content C4 of the copper element is 2/1 to 50/1. It is more preferably blended so as to be 1 and even more preferably 5/1 to 30/1. By setting the molar ratio C3 / C4 to 2/1 or more, copper precipitation and metal corrosion can be further suppressed. By setting the molar ratio C3 / C4 to 50/1 or less, metal properties such as toughness and rigidity are not impaired. Corrosion can be further suppressed.

  Examples of the alkali metal salt and alkaline earth metal salt include, but are not limited to, hydroxides such as sodium, potassium, magnesium, calcium and barium, and carbonates, phosphates and silicates of the above metals. Salts, borates, carboxylate salts. From the viewpoint of improving the thermal stability of the resin gear, specifically, a calcium salt is preferable.

  Examples of the calcium salt include, but are not limited to, calcium hydroxide, calcium carbonate, calcium phosphate, calcium silicate, calcium borate, and fatty acid calcium salts (such as calcium stearate and calcium myristate). The fatty acid component of the fatty acid calcium salt may be substituted with, for example, a hydroxyl group. Among them, fatty acid calcium salts (such as calcium stearate and calcium myristate) are more preferable from the viewpoint of improving the thermal stability of the resin gear.

  The upper limit of the content of the alkali metal salt and the alkaline earth metal salt in the resin gear is preferably 0.6 parts by mass, and more preferably 0.4 parts by mass with respect to 100 parts by mass of the thermoplastic resin (A). And more preferably 0.3 parts by mass. The lower limit of the content of the alkali metal salt and the alkaline earth metal salt is preferably 0.005 part by mass, and more preferably 0.01 part by mass, based on 100 parts by mass of the thermoplastic resin (A). More preferably, it is still more preferably 0.015 parts by mass. When the lower limit of the content of the alkali metal salt and the alkaline earth metal salt is within the above range, the heat aging resistance is further improved. Further, when the upper limit of the content of the alkali metal salt and the alkaline earth metal salt is within the above range, the thermal decomposition of the resin gear can be further suppressed.

  (D) The method of causing the metal ion component to be present in the resin gear includes, for example, (A) a copper compound (if necessary, a metal halide or an alkali metal salt) at the time of polymerization of the thermoplastic resin (Production Method 1). And / or an alkaline earth metal salt), a melt kneading (manufacturing method 2), a copper compound (if necessary, a metal halide, an alkali metal salt, and / or Or an alkaline earth metal salt).

  In the method of manufacturing the resin gear of the present embodiment, the copper compound may be added in a solid state, for example, in a state of an aqueous solution. The term (A) at the time of the polymerization of the thermoplastic resin in the production method 1 may be any stage until the polymerization of the raw material monomer into the polymer is completed. The apparatus for performing the melt-kneading in Production Method 2 is not particularly limited, and a known apparatus, for example, a melt-kneader such as a single-screw or twin-screw extruder, a Banbury mixer, and a mixing roll can be used. . Among them, a twin-screw extruder is preferably used.

The temperature of the melt-kneading is preferably a temperature about 1 to 100 ° C. higher than the melting point of the thermoplastic resin (A), more preferably a temperature about 10 to 50 ° C. higher. The shear rate in the kneader is preferably about 100 sec ^-1 or more, and the average residence time during kneading is preferably about 0.5 to 5 minutes.

{(E) Sliding agent component}
Next, the (E) sliding agent component that can be used in the present invention will be described in detail. The resin gear of the present embodiment can contain (E) a sliding agent component as an additional component. These may be commercially available reagents or products.

  The preferred lower limit of the (E) sliding agent component is 0.01 part by mass, more preferably 0.5 part by mass, particularly preferably 1 part by mass, per 100 parts by mass of the thermoplastic resin (A). 0.0 parts by mass. Further, the preferred upper limit of the sliding agent component (E) is 5 parts by mass, more preferably 4 parts by mass, particularly preferably 3 parts by mass with respect to 100 parts by mass of the thermoplastic resin (A). . (E) By setting the amount of the sliding agent component in the above range, the amount of wear can be suppressed, and the number of breaks in a repeated fatigue test is improved. When a normal filler (for example, glass fiber or the like) is used, (E) the sliding agent component is unevenly distributed on the filler surface, and a large number of sliding agent molecules are laminated, so that the filler is likely to fall off, and long-term fatigue. In tests and the like, there may be a problem that the effect is reduced. However, in the case of (B) nanocellulose having an average fiber diameter of 1000 nm or less, since the surface area is largely different from that of glass fiber or the like and is large, the (E) sliding agent component is hardly unevenly distributed on the cellulose surface. Difficulty in stacking molecules. Thereby, it is presumed that the number of breaks in the fatigue test is improved and the wear resistance is also maintained.

  When the amount of the sliding agent component (E) is 5 parts by mass or less based on 100 parts by mass of the thermoplastic resin (A), delamination and generation of silver streaks in the resin molded product are more favorably suppressed. When the amount of the sliding agent component (E) is at least 0.01 part by mass with respect to the thermoplastic resin (A), a more remarkable effect of reducing the wear amount can be obtained.

Examples of the (E) sliding agent component include compounds having a structure represented by the following general formula (1), (2) or (3).
_{[R 11 - (A 1 -R} 12) x -A 2 -R 13] y ··· (1)
_{A 3 -R 11 -A 4 ··· (} 2)
R ₁₄ -A ₅ (3)
Here, in the formulas (1) and (2), R ₁₁ , R ₁₂ and R ₁₃ are each independently an alkylene group having 1 to 7000 carbon atoms or a substituted or unsubstituted alkylene group having 1 to 7000 carbon atoms. A substituted alkylene group in which at least one hydrogen atom is substituted with an aryl group having 6 to 7000 carbon atoms, an arylene group having 6 to 7000 carbon atoms, or at least one hydrogen atom in an arylene group having 6 to 7000 carbon atoms is It is a substituted arylene group substituted with a substituted or unsubstituted alkyl group having 1 to 7000 carbon atoms.

In the formula (3), R ₁₄ represents an alkyl group having 1 to 7000 carbon atoms or an aryl group having at least one hydrogen atom of a substituted or unsubstituted alkyl group having 1 to 7000 carbon atoms. Wherein at least one hydrogen atom in a substituted alkyl group, an aryl group having 6 to 7,000 carbon atoms, or an aryl group having 6 to 7,000 carbon atoms is substituted with a substituted or unsubstituted alkyl group having 1 to 7,000 carbon atoms. Substituted aryl group.

  These groups may be groups containing a double bond, a triple bond, or a cyclic structure.

In the formula (1), A ₁ and A ₂ each independently represent an ester bond, a thioester bond, an amide bond, a thioamide bond, an imide bond, a ureide bond, an imine bond, a urea bond, a ketoxime bond, an azo bond, It is an ether bond, a thioether bond, a urethane bond, a thiourethane bond, a sulfide bond, a disulfide bond, or a trisulfide bond.

In the formulas (2) and (3), A ₃ , A ₄ and A ₅ each independently represent a hydroxyl group, an acyl group (for example, an acetyl group), an aldehyde group, a carboxyl group, an amino group, a sulfo group, Amidine group, azi group, cyano group, thiol group, sulfenic acid group, isocyanide group, ketene group, isocyanate group, thioisocyanate group, nitro group, or thiol group.

  From the viewpoint of the wear characteristics when sliding under a minute load, it is preferable that the structure represented by the general formulas (1), (2), and (3) in the (E) sliding agent component be within the following range.

That is, the number of carbon atoms in R ₁₁ , R ₁₂ , R ₁₃ , and R ₁₄ is preferably 2 to 7000, more preferably 3 to 6800, and still more preferably 4 to 6500.
In the formula (1), x represents an integer of 1 to 1000, preferably an integer of 1 to 100. y represents an integer of 1 to 1000, preferably an integer of 1 to 200.

In the formula (1), preferred A ₁ and A ₂ are each independently an ester bond, a thioester bond, an amide bond, an imide bond, an ureide bond, an imine bond, a urea bond, a ketoxime bond, an ether bond, and a urethane bond. Preferred and more preferred A ₁ and A ₂ are each independently an ester bond, an amide bond, an imide bond, a ureide bond, an imine bond, a urea bond, a ketoxime bond, an ether bond, and a urethane bond.

In the formulas (2) and (3), preferred A ₃ , A ₄ and A ₅ are each independently a hydroxyl group, an acyl group (for example, an acetyl group), an aldehyde group, a carboxyl group, an amino group, an azi group, a cyano group. Groups, thiol groups, isocyanide groups, ketene groups, isocyanate groups, and thioisocyanate groups, more preferably A ₃ , A ₄ and A ₅ are each independently a hydroxyl group, an acyl group (for example, an acetyl group), an aldehyde Group, carboxyl group, amino group, cyano group, isocyanide group, ketene group, and isocyanate group.

  Specifically, the sliding agent component (E) is not particularly limited, and may be, for example, a group consisting of alcohol, amine, carboxylic acid, hydroxy acid, amide, ester, polyoxyalkylene glycol, silicone oil, and wax. At least one compound selected is exemplified.

  As the alcohol, a saturated or unsaturated monohydric or polyhydric alcohol having 6 to 7000 carbon atoms is preferable. Specific examples are not particularly limited, for example, octyl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, lauryl alcohol, tridecyl alcohol, myristyl alcohol, pentadecyl alcohol, cetyl alcohol, heptadecyl alcohol, stearyl alcohol, Oleyl alcohol, linolyl alcohol, nonadecyl alcohol, eicosyl alcohol, seryl alcohol, behenyl alcohol, melisyl alcohol, hexyl decyl alcohol, octyl dodecyl alcohol, decyl myristyl alcohol, decyl stearyl alcohol, uniline alcohol, ethylene glycol, diethylene glycol, triethylene glycol Ethylene glycol, propylene glycol, dipropylene glycol, butane Ol, pentanediol, hexanediol, glycerol, diglycerol, triglycerol, threitol, erythritol, pentaerythritol, arabitol, ribitol, xylitol, sorbite, sorbitan, sorbitol, mannitol.

  Among them, alcohols having 11 or more carbon atoms are preferable from the viewpoint of the efficiency of the slidability. More preferably, it is an alcohol having 12 or more carbon atoms, and further preferably, an alcohol having 13 or more carbon atoms. Particularly preferred among these are saturated alcohols.

  Of these, stearyl alcohol, oleyl alcohol, linolyl alcohol, behenyl alcohol, ethylene glycol, propylene glycol, diethylene glycol, and triethylene glycol are preferably used, and behenyl alcohol, diethylene glycol, and triethylene glycol are particularly preferably used.

  Examples of the amine include, but are not limited to, primary amines, secondary amines, and tertiary amines.

  The primary amine is not particularly limited, for example, methylamine, ethylamine, propanamine, butanamine, pentanamine, hexaneamine, heptamine, octaneamine, cyclohexylamine, ethylenediamine, aniline, mensendiamine, isophoronediamine, xylenediamine , Metaphenylenediamine, diaminodiphenylamine and the like.

  Although it does not specifically limit as a secondary amine, For example, dimethylamine, diethylamine, N-methylethylamine, diphenylamine, tetramethylethylenediamine, piperidine, N, N-dimethylpiperazine, etc. are mentioned.

  The tertiary amine is not particularly limited, but includes, for example, trimethylamine, triethylamine, hexamethylenediamine, N, N-diisopropylethylamine, pyridine, N, N-dimethyl-4-aminopyridine, triethylenediamine, benzyldimethylamine and the like. Can be

  Although it does not specifically limit as a special amine, For example, diethylene triamine, triethylene tetramine, tetraethylene pentamine, diethylamino ropylamine, N-aminoethyl piperazine, etc. are mentioned. Among these, hexaneamine, heptaneamine, octaneamine, tetramethylethylenediamine, N, N-dimethylpiperazine, hexamethylenediamine can be more preferably used, and among these, heptaneamine, octaneamine, tetramethylethylenediamine, hexamethylenediamine Methylene diamine can be used particularly preferably.

  As the carboxylic acid, a saturated or unsaturated monovalent or polyvalent aliphatic carboxylic acid having 6 to 7000 carbon atoms is preferable. Specific examples are not particularly limited, for example, caproic acid, enanthic acid, caprylic acid, undecylic acid, pelargonic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, stearic acid, nanodecane Acids, arachinic acid, behenic acid, lignoceric acid, cerotic acid, heptaconic acid, montanic acid, etc., adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, melicic acid, raccelic acid, undecylenic acid, elaidic acid, setraic acid , Brassic acid, sorbic acid, palmitoleic acid, oleic acid, vaccenic acid, linoleic acid, linolenic acid, eleostearic acid, arachidonic acid, nervonic acid, erucic acid, propiolic acid, stearolic acid and the like.

  Among them, fatty acids having 10 or more carbon atoms are preferable from the viewpoint of the efficiency of the slidability. More preferably, it is a fatty acid having 11 or more carbon atoms, and further preferably, a fatty acid having 12 or more carbon atoms. Particularly preferred among these are saturated fatty acids. Among the saturated fatty acids, palmitic acid, stearic acid, behenic acid, montanic acid, adipic acid, sebacic acid and the like are easily available industrially and are more preferable.

  In addition, a naturally occurring fatty acid containing such a component or a mixture thereof may be used. These fatty acids may be substituted with a hydroxy group, or may be synthetic fatty acids obtained by carboxyl-modifying the terminal of unilin alcohol which is a synthetic aliphatic alcohol.

  Although it does not specifically limit as a hydroxy acid, For example, an aliphatic hydroxy acid and an aromatic hydroxy acid are mentioned. The aliphatic hydroxy acid is not particularly limited, for example, glycolic acid, hydroxypropionic acid, hydroxybutanoic acid, hydroxypentanoic acid, hydroxyhexanoic acid, hydroxyheptanoic acid, hydroxynonanoic acid, hydroxydecanoic acid, hydroxyundecanoic acid, hydroxy Dodecanoic acid, hydroxytridecanoic acid, hydroxytetradecanoic acid, hydroxypentadecanoic acid, hydroxyhexadecanoic acid, hydroxyheptadecanoic acid, hydroxyoctadecanoic acid, hydroxynonadecanoic acid, hydroxyicosanoic acid, hydroxydocosanoic acid, hydroxytetradocosanoic acid, Hydroxyhexadocosanoic acid, hydroxyoctadocosanoic acid or lactic acid, tartronic acid, glyceric acid, hydroxybutyric acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, γ- Droxybutyric acid, malic acid, tartaric acid, citramalic acid, citric acid, isocitric acid, leucic acid, mevalonic acid, pantoic acid, ricinoleic acid, ricineraidic acid, cerebronic acid, quinic acid, shikimic acid, and the like, and isomers thereof It may be.

  The aromatic hydroxy acid is not particularly limited. For example, salicylic acid, creosoteric acid (homosalicylic acid, hydroxy (methyl) benzoic acid) as a monohydroxybenzoic acid derivative, vanillic acid, syringic acid, pyrocatechuic acid as a dihydroxybenzoic acid derivative, As resorcylic acid, protocatechuic acid, gentisic acid, orseric acid, trihydroxybenzoic acid derivatives, gallic acid, phenylacetic acid derivatives, mandelic acid, benzylic acid, atrolactic acid, cinnamic acid and hydrocinnamic acid derivatives, melilotic acid, phloretic acid , Coumaric acid, umbellic acid, caffeic acid, ferulic acid, sinapic acid, and isomers thereof. Among these, aliphatic hydroxy acids are more preferred, among them, aliphatic hydroxy acids having 5 to 30 carbon atoms are more preferred, and aliphatic hydroxy acids having 8 to 28 carbon atoms are particularly preferred.

  As the amide, a saturated or unsaturated monovalent or polyvalent aliphatic amide having 6 to 7000 carbon atoms is preferable. Specific examples are not particularly limited. For example, as primary amides, heptane amide, octane amide, nonanamide, decanamide, undecane amide, lauryl amide, tridecyl amide, myristyl amide, pentadecyl amide, cetyl amide, hepta decyl amide, Stearyl amide, oleyl amide, nonadecyl amide, eicosyl amide, ceryl amide, behenyl amide, meryl amide, hexyl decyl amide, octyl dodecyl amide, lauric amide, palmitic amide, stearic amide, behenic amide, hydroxystearic amide, oleic acid Saturated or unsaturated amides such as amides and erucic acid amides are exemplified.

  Examples of secondary amides include, but are not limited to, N-oleyl palmitic amide, N-stearyl stearamide, N-stearyl oleic amide, N-oleyl stearamide, N- Stearyl erucic acid amide, methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, ethylene bisoleic acid amide, ethylene bis And saturated or unsaturated amides such as erucamide, hexamethylenebisstearic acid amide, hexamethylenebisbehenic acid amide, hexamethylenebisoleic acid amide, hexamethylenehydroxystearic acid amide and the like. That.

  Examples of tertiary amides include, but are not limited to, N, N-distearyl adipamide, N, N-distearyl sebacic amide, N, N-dioleyl adipamide, Saturated or unsaturated amides such as N, N-dioleyl sebacamide, N, N-distearylisophthalamide.

  Among these, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, oleic acid amide, erucic acid amide, and N-stearyl stearic acid amide can be more preferably used.

  Among these, methylenebisstearic acid amide, ethylenebislauric acid amide, ethylenebisstearic acid amide, and ethylenebisbehenic acid amide can be preferably used. Among these, amides having 10 or more carbon atoms are preferable from the viewpoint of the efficiency of the slidability. More preferably, it is an amide having 11 or more carbon atoms, and further preferably, an amide having 13 or more carbon atoms. Particularly preferred among these are the saturated aliphatic amides.

  As the ester, a reaction product or the like in which the above-mentioned alcohol is reacted with a carboxylic acid or a hydroxy acid to form an ester bond is preferable.

  Specific examples are not particularly limited, for example, butyl stearate, 2-ethylhexyl palmitate, 2-ethylhexyl stearate, monoglyceride behenate, cetyl 2-ethylhexanoate, isopropyl myristate, isopropyl palmitate, Cholesteryl isostearate, methyl laurate, methyl oleate, methyl stearate, cetyl myristate, myristyl myristate, octyl dodecyl pentaerythritol monooleate, pentaerythritol monostearate, pentaerythritol tetrapalmitate, stearyl stearate, Isotridecyl stearate, 2-ethylhexanoic acid triglyceride, diisodecyl adipate, ethylene glycol monolaurate, ethylene glycol Coal dilaurate, ethylene glycol monostearate, ethylene glycol distearate, triethylene glycol monostearate, triethylene glycol distearate, ethylene glycol monooleate, ethylene glycol dioleate, polyethylene glycol monolaurate, polyethylene glycol mono Examples include stearate, polyethylene glycol distearate, polyethylene glycol monooleate, glycerin monostearate, glycerin distearate, glycerin monolaurate, glycerin dilaurate, glycerin monooleate, glycerin dioleate and the like.

  Among these, cetyl myristate, diisodecyl adipate, ethylene glycol monostearate, ethylene glycol distearate, triethylene glycol monostearate, triethylene glycol distearate, polyethylene glycol monostearate, and polyethylene glycol distearate are preferred. Cetyl myristate, diisodecyl adipate, and ethylene glycol distearate can be particularly preferably used.

  Examples of the polyoxyalkylene glycol include, but are not limited to, the following three types.

  The first polyoxyalkylene glycol is a polycondensate using alkylene glycol as a monomer. Examples of such polycondensates include, but are not limited to, polyethylene glycol, polypropylene glycol, block copolymers of ethylene glycol and propylene glycol, and random copolymers. The preferred range of the degree of polymerization of these polycondensates is 5 to 2500, more preferably 10 to 2300.

  The second polyoxyalkylene glycol is an ether compound of the polycondensate mentioned for the first polyoxyalkylene glycol and an aliphatic alcohol. Examples of such an ether compound include, but are not limited to, polyethylene glycol oleyl ether (ethylene oxide polymerization degree: 5-500), polyethylene glycol cetyl ether (ethylene oxide polymerization degree: 5-500), polyethylene glycol Stearyl ether (ethylene oxide polymerization degree 5 to 300), polyethylene glycol lauryl ether (ethylene oxide polymerization degree 5 to 300), polyethylene glycol tridecyl ether (ethylene oxide polymerization degree 5 to 300), polyethylene glycol nonyl phenyl ether (ethylene oxide polymerization Degree 2 to 1000), and polyethylene glycol oxytyl phenyl ether (ethylene oxide polymerization degree 4 to 500).

  The third polyoxyalkylene glycol is an ester compound of the polycondensate mentioned for the first polyoxyalkylene glycol and a higher fatty acid. Examples of such ester compounds include, but are not limited to, polyethylene glycol monolaurate (ethylene oxide polymerization degree of 2-300), polyethylene glycol monostearate (ethylene oxide polymerization degree of 2-500), Polyethylene glycol monooleate (ethylene oxide polymerization degree: 2 to 500);

  Examples of the wax include, but are not particularly limited to, for example, shrub wax, beeswax, whale wax, shellac wax, wool wax, carbana wax, wood wax, rice wax, candelilla wax, wax, paraffin wax, microcrystalline wax. , Montan wax, Fischer-Tropsch wax, polyethylene wax, polypropylene wax, and high-density polymerization type, low-density polymerization type, oxidation type, acid-modified type, and special monomer-modified type thereof.

  Among them, carnauba wax, rice wax, candelilla wax, paraffin wax, montan wax, polyethylene wax and their high-density polymerization type, low-density polymerization type, oxidized type, acid-modified type, and special monomer-modified type can be more preferably used. Among them, carnauba wax, rice wax, candelilla wax, paraffin wax, polyethylene wax, and high-density polymerization type, low-density polymerization type, oxidized type, acid-modified type and special monomer-modified type thereof can be particularly preferably used.

  Among them, (E) the sliding agent component includes at least one selected from the group consisting of alcohols, amines, carboxylic acids, esters, amide compounds composed of monovalent or divalent amines and carboxylic acids, and waxes. Preferably, it is a compound.

  The paraffin wax, polyethylene wax, and high-density polymerization type, low-density polymerization type, oxidized type, acid-modified type, and special monomer-modified type (E) of the sliding agent component used in the polyamide resin composition of the present embodiment are particularly preferable. Although not limited, an acidic group is introduced by an oxidation reaction of a polyolefin wax, or a polyolefin is oxidatively decomposed, and an inorganic acid, an organic acid or an unsaturated carboxylic acid is reacted with the polyolefin wax to form a carboxyl group or a sulfonic acid group. It can be obtained by introducing a polar group or by introducing a monomer having an acidic group during polymerization of the polyolefin wax.

  These are commercially available under the name of oxidation-modified or acid-modified polyolefin wax and can be easily obtained.

  Examples of the polyolefin wax include, but are not limited to, paraffin wax, microcrystalline wax, montan wax, Fischer-Tropsch wax, polyethylene wax, polypropylene wax, and their high-density polymerization type, low-density polymerization type, specialty And a monomer-modified type.

  Examples of the polyolefin include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-octene copolymer, polypropylene-butene copolymer, polybutene, hydrogenated polybutadiene, ethylene-acrylic acid Examples include an ester copolymer, an ethylene-methacrylic acid ester copolymer, an ethylene-acrylic acid copolymer, an ethylene-vinyl acetate copolymer, and the like.

  (E) As a sliding agent component, an acid-modified paraffin wax, polyethylene wax, polypropylene wax, polyethylene (high-pressure low-density polyethylene, linear low-density polyethylene, ultra-low-density polyethylene) from the viewpoint of the sliding property improving effect , Polypropylene, an ethylene-propylene copolymer, and an acid-modified ethylene-butene copolymer are preferred.

  (E) The sliding agent component is particularly preferably a modified wax containing acid-modified polyethylene and / or acid-modified polypropylene.

As the sliding agent component (E), one type may be used alone, or two or more types may be used in combination.
In the present embodiment, the molecular structure, molecular weight, melting point, acid value, viscosity, and the like can be calculated by separating the sliding agent component (E) from the resin gear (that is, the molded product).

The (E) sliding agent component in the molded product should be isolated by dissolving the molded product and then performing an operation such as separation, and then purifying the (E) sliding agent component by an operation such as recrystallization or reprecipitation. Is possible. (E) The sliding agent component is subjected to various measurements such as ¹ H-NMR, ¹³ C-NMR, two-dimensional NMR, and MALDI-TOF MS to obtain a molecular structure such as a repeating structure, a branched structure, and positional information of various functional groups. Can be determined.

  (E) When the sliding agent component is an acid-modified polyethylene and / or an acid-modified polypropylene, the acid value is preferably in the range of 0 to 85 mg-KOH / g. There is no particular lower limit for the acid value, but it is preferably 0 mg-KOH / g or more. The more preferable upper limit of the acid value is 83 mg-KOH / g, further preferably 80 mg-KOH / g, and still more preferably 75 mg-KOH / g. When the acid value is in the above range, discoloration during drying is suppressed, and abrasion resistance during high-temperature sliding with a small load tends to be improved. (E) The acid value of the sliding agent component can be measured by a method according to JIS K0070.

  (E) The acid value of the sliding agent component can be determined by, for example, the method described in Example 1 or 2 of JP-A-2004-75749, or by thermally decomposing commercially available high-density polyethylene in an oxygen atmosphere. It can be controlled by a method of adjusting or controlling the introduced amount and / or the introduced amount of the polar group. When (E) the sliding agent component is an acid-modified polyethylene and / or an acid-modified polypropylene, it is also possible to use a commercially available product.

  (E) When the sliding agent component is acid-modified polyethylene and / or acid-modified polypropylene, the melt viscosity at 140 ° C. is preferably in the range of 1 to 3000 mPa · s. Although the lower limit is not particularly limited, it is preferably 1 mPa · s, more preferably 20 mPa · s, and still more preferably 25 mPa · s, from the viewpoint of processability during melt-kneading of the polyamide resin composition of the present embodiment. Yes, still more preferably 30 mPa · s, and still more preferably 50 mPa · s. The preferred upper limit of the 140 ° C. melt viscosity is 2850 mPa · s, more preferably 2800 mPa · s, still more preferably 2700 mPa · s, still more preferably 2650 mPa · s, and still more preferably 2000 mPa · s.

  (E) When the sliding agent component is an acid-modified polyethylene and / or an acid-modified polypropylene, the melt viscosity at 180 ° C. is preferably in the range of 100 to 2900 mPa · s. (E) When the sliding agent component is acid-modified polyethylene and / or acid-modified polypropylene, the lower limit of the 180 ° C. melt viscosity is preferably 110 mPa · s, more preferably 140 mPa · s, and still more preferably 160 mPa · s. S, and still more preferably 300 mPa · s. Further, when the sliding agent component (E) is an acid-modified polyethylene and / or an acid-modified polypropylene, the preferable upper limit of the melt viscosity at 180 ° C. is 2850 mPa · s, more preferably 2800 mPa · s, and further preferably 2700 mPa · s. S, still more preferably 2650 mPa · s, still more preferably 2000 mPa · s, and particularly preferably 1600 mPa · s.

  (E) When the sliding agent component is an acid-modified polyethylene and / or an acid-modified polypropylene, the melt viscosity is set within the above range, so that the resin composition as a constituent material of the resin gear of the present embodiment is melt-kneaded. At times, the resin pellets are completely melted and tend to be sufficiently kneaded.

  (E) When the sliding agent component is an acid-modified polyethylene and / or an acid-modified polypropylene, the melt viscosity at 140 ° C. and 180 ° C. can be measured with a Brookfield viscometer.

  (E) The lubricating oil that can be used as the sliding agent component is not limited to the following, but may be any substance that can improve the friction and wear characteristics of the thermoplastic resin molded article. Oils such as oils and cylinder oils; paraffin oils (such as Diana Process Oil PS32 manufactured by Idemitsu Kosan Co., Ltd.), naphthenic oils (such as Diana Process Oil NS90S manufactured by Idemitsu Kosan Co., Ltd.), and aroma oils (Diana manufactured by Idemitsu Kosan Co., Ltd.) Synthetic oils such as process oil AC12); silicone oils such as silicone grease (G30 series manufactured by Shin-Etsu Chemical Co., Ltd.); silicone oils represented by polydimethylsiloxane; silicone gums; modified silicone gums; Can be generally marketed Select and from the lubricating oil is suitably, as it is or may be used appropriately in the formulation if desired. Of these, paraffinic oils and silicone oils are preferred from the viewpoint of slidability, and are easily available industrially and are preferred. These lubricating oils may be used alone or in combination.

  The lower limit of the molecular weight of the lubricating oil is preferably 100, more preferably 400, and even more preferably 500. The upper limit is preferably 5,000,000, more preferably 2,000,000, and still more preferably 1,000,000. The lower limit of the melting point of the lubricating oil is preferably −50 ° C., more preferably −30 ° C., and even more preferably −20 ° C. The upper limit of the melting point of the lubricating oil is preferably 50 ° C, more preferably 30 ° C, even more preferably 20 ° C. When the molecular weight is 100 or more, the lubricating oil tends to have good slidability. Further, when the molecular weight is 5,000,000 or less, particularly 1,000,000 or less, the dispersion of the lubricating oil is good, and the abrasion resistance tends to be improved. Further, by setting the melting point to -50 ° C or higher, the fluidity of the lubricating oil present on the surface of the molded body is maintained, and the wear resistance of the molded body tends to be improved by suppressing abrasive wear. When the melting point is 50 ° C. or less, the lubricating oil is easily kneaded with the thermoplastic resin (A), and the dispersibility of the lubricating oil tends to be improved. From the viewpoints described above, it is preferable that the molecular weight and the melting point of the lubricating oil be within the above ranges. The above melting point means a temperature lower by 2.5 ° C. than the pour point of the lubricating oil, and the pour point is a value measured according to JIS K2269.

  (A) The lower limit of the content of the lubricating oil based on 100 parts by mass of the thermoplastic resin is not particularly limited, but is preferably 0.1 part by mass, more preferably 0.2 part by mass, and further more preferably 0.3 part by mass. preferable. The upper limit of the content is not particularly limited, but is preferably 5.0 parts by mass, more preferably 4.5 parts by mass, and still more preferably 4.2 parts by mass. When the content of the lubricating oil is in the above-mentioned range, the wear resistance of the resin composition as a constituent material of the resin gear tends to be improved. In particular, when the content of the lubricating oil is 0.1 parts by mass or more, good slidability can be ensured, and abrasion resistance tends to be improved. Further, when the content of the lubricating oil is 5.0 parts by mass or less, the softening of the resin can be suppressed, and the strength of the resin composition that can withstand applications such as helical gears tends to be secured. Therefore, when the range of the lubricating oil content in the resin gear of the present embodiment is adjusted as described above, it is preferable from the viewpoint of improving the abrasion characteristics at the time of sliding and excellent in the stable sliding property.

  In resin gears, the weight average molecular weight of (E) the sliding agent component is important because the dispersion state of the sliding agent component in the vicinity of the surface layer greatly affects the sliding characteristics. (E) A preferable lower limit of the weight average molecular weight of the sliding agent component is 500, more preferably 600, and particularly preferably 700. Although there is no particular upper limit of the weight average molecular weight of the (E) sliding agent component, 100000 is a rough standard because of easy handling. In the resin gear of the present embodiment, by maintaining the weight average molecular weight of the sliding agent component (E) in the above-described range, it is possible to achieve the maintenance of wear resistance when the number of sliding operations exceeds 10,000.

  (E) There is no particular lower limit on the molecular weight distribution of the sliding agent component, but from the viewpoint of the stability of the friction coefficient during sliding, it is a guideline to be close to 1.0. The preferred upper limit of the molecular weight distribution of the sliding agent component (E) is 9.0, more preferably 8.5, still more preferably 8.0, and even more preferably 7.5.

  (E) The weight average molecular weight of the sliding agent component is measured by liquid chromatography / mass spectrometry when the weight average molecular weight is 1000 or less, and measured by gel permeation chromatography when the weight average molecular weight exceeds 1000. And expressed in terms of weight average molecular weight in terms of standard polystyrene or the like.

  (E) The sliding agent component preferably has a melting point of 40 to 150 ° C. By setting the melting point of the sliding agent component (E) to 40 ° C. or higher, the wear resistance of the resin molded article at a higher temperature tends to be improved. By setting the melting point to 150 ° C. or less, it becomes easy to achieve good dispersion of the (E) sliding agent component in the resin during processing. (E) A more preferred lower limit of the melting point of the sliding agent component is 45 ° C, a further preferred lower limit is 50 ° C, and a particularly preferred lower limit is 80 ° C. Further, the more preferable upper limit of the melting point of the sliding agent component (E) is 140 ° C, more preferably 135 ° C, particularly preferably 130 ° C. (E) The melting point of the sliding agent component can be measured by a method according to JIS K 7121 (DSC method).

≪Other ingredients≫
The resin gear of the present embodiment can contain various stabilizers conventionally used in thermoplastic resins as long as the object of the present embodiment is not impaired. Examples of the stabilizer include, but are not limited to, the following inorganic fillers and heat stabilizers. These may be used alone or in combination of two or more. These may be commercially available reagents or products.

  The inorganic filler is not limited to the following, but is, for example, at least one compound selected from the group consisting of fibrous particles, plate-like particles, and inorganic pigments. Here, the fibrous particles and the plate-like particles are particles in which the average aspect ratio of the fibrous particles and the plate-like particles existing in the polyacetal resin molded product is 5 or more.

  Examples of the fibrous particles include, but are not particularly limited to, glass fibers, carbon fibers, potassium titanate fibers, asbestos fibers, silicon carbide fibers, silicon nitride fibers, calcium metasilicate fibers, and aramid fibers.

  The plate-like particles are not particularly limited, and examples thereof include talc, mica, kaolin, glass flake, bentonite, and the like. Of these, talc, mica, and glass fiber are preferred. By using these, it tends to be more excellent in mechanical strength and more economical.

  Examples of the inorganic pigment include, but are not particularly limited to, for example, zinc sulfide, titanium oxide, zinc oxide, iron oxide, barium sulfate, titanium dioxide, barium sulfate, hydrated chromium oxide, chromium oxide, cobalt aluminate, barite powder, zinc yellow. 1 kind, zinc yellow 2 kinds, ferrocyanide iron caricaolin, titanium yellow, cobalt blue, ultramarine blue, cadmium, nickel titanium, lithopone, strontium, amber, sienna, azurite, malachite, azlo malachite, opiment, real gar, cinnabar, Turquoise, rhodochrosite, yellow ocher, tail belt, roshenna, roo amber, kassel earth, chalk, plaster, burnt sienna, burnt amber, lapis lazuli, azurite, malachite, coral powder, white mica, cobalt blue, se Lian Blue, Cobalt Violet, Cobalt Green, Zinc White, Titanium White, Light Red, Chrome Oxide Green, Mars Black, Viridian, Yellow Ocher, Alumina White, Cadmium Yellow, Cadmium Red, Vermillion, Talc, White Carbon, Clay, Mineral Bio Red, Rose Cobalt Violet, Silver White, Gold Powder, Bronze Powder, Aluminum Powder, Prussian Blue, Aureolin, Mica Titanium, Carbon Black, Acetylene Black, Lamp Black, Furnas Black, Vegetable Black, Bone Charcoal, Calcium Carbonate, Navy Blue No.

  Among these, zinc sulfide, zinc oxide, iron oxide, titanium dioxide, titanium yellow, cobalt blue, and carbonate are preferable from the viewpoint of imparting higher wear resistance, and zinc oxide and titanium yellow have a sufficient Mohs hardness. From the viewpoint of imparting even higher wear resistance.

  Although the addition amount of the above-mentioned inorganic filler is not particularly limited, it is preferable that the amount of the inorganic filler is in the range of 0.002 to 70 parts by mass with respect to 100 parts by mass of the thermoplastic resin (A). By setting the addition amount of the inorganic filler within the above range, the handleability of the resin composition can be improved.

  As the heat stabilizer, a hindered phenol-based antioxidant is preferable from the viewpoint of improving the heat stability of the resin molded article.

  Examples of the hindered phenol-based antioxidant include, but are not limited to, n-octadecyl-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) -propionate, n-octadecyl-3- (3'-methyl-5'-t-butyl-4'-hydroxyphenyl) -propionate, n-tetradecyl-3- (3 ', 5'-di-t-butyl-4'- (Hydroxyphenyl) -propionate, 1,6-hexanediol-bis- (3- (3,5-di-t-butyl-4-hydroxyphenyl) -propionate), 1,4-butanediol-bis- (3- (3,5-di-tert-butyl-4-hydroxyphenyl) -propionate), triethylene glycol-bis- (3- (3-tert-butyl-5-methyl-4-hydroxy) Phenyl) - propionate), and the like.

  Examples of the hindered phenol-based antioxidant include, but are not limited to, tetrakis- (methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) pro Pionate methane, 3,9-bis (2- (3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy) -1,1-dimethylethyl) -2,4,8,10 -Tetraoxaspiro (5,5) undecane, N, N'-bis-3- (3 ', 5'-di-tert-butyl-4-hydroxyphenol) propionylhexamethylenediamine, N, N'- Tetramethylenebis-3- (3'-methyl-5'-t-butyl-4-hydroxyphenol) propionyldiamine, N, N'-bis- (3- (3,5-di-t-butyl-4- Hydroxy Enol) propionyl) hydrazine, N-salicyloyl-N'-salicylidenehydrazine, 3- (N-salicyloyl) amino-1,2,4-triazole, N, N'-bis (2- (3- (3,3 5-di-butyl-4-hydroxyphenyl) propionyloxy) ethyl) oxyamide and the like.

  Among the above hindered phenolic antioxidants, from the viewpoint of improving the thermal stability of the resin molded product, triethylene glycol-bis- (3- (3-t-butyl-5-methyl-4-hydroxyphenyl)- Propionate) and tetrakis- (methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate) methane are preferred.

  Although the addition amount of the above-mentioned antioxidant is not particularly limited, the antioxidant, for example, 0.1 to 2 parts by mass of a hindered phenol-based antioxidant is used per 100 parts by mass of the thermoplastic resin. It is preferably within the range. By controlling the addition amount of the antioxidant within the above range, the handleability of the resin composition can be improved.

また、算術平均表面粗さＳａとは、算術平均表面粗さＲａを面に拡張したものであり下記式（５）で表される。

{Arithmetic average surface roughness of gear sliding surface Sa}
In the resin gear of the present embodiment, the surface roughness of the sliding surface with the other gear teeth needs to be 3.0 μm or less in arithmetic average surface roughness Sa. The arithmetic average surface roughness Sa is a value obtained by a measurement method based on ISO25178, and can be obtained by extending the arithmetic average surface roughness Ra to a surface. The arithmetic average surface roughness Ra conforms to JIS B0031, and is a roughness on a sliding surface of the resin gear with other gear teeth (the sliding surface can be specified by a person skilled in the art based on the shape of the resin gear). The roughness curve is measured, and only the reference length (a) is extracted in the average line direction of the roughness curve, the direction of the average line of the extracted portion is set as the X axis, the direction of the vertical magnification is set as the Y axis, and the roughness curve is set as y. = F (x) means a value obtained by the following equation (4) expressed in micrometers (μm).

The arithmetic average surface roughness Sa is obtained by extending the arithmetic average surface roughness Ra to a surface, and is represented by the following equation (5).

  The upper limit of the arithmetic mean surface roughness Sa is preferably 0.9 μm, more preferably 0.8 μm, still more preferably 0.7 μm, and most preferably 0.6 μm. The lower limit of the arithmetic mean surface roughness Sa is not particularly limited, but is preferably, for example, 0.1 μm from the viewpoint of manufacturability. The surface roughness can be measured using a commercially available microscope device such as a confocal microscope (for example, OPTELICS (registered trademark) H1200, manufactured by Lasertec Corporation).

≪void≫
The fewer voids in the resin gear, the better. The presence of the voids causes a stress concentration due to the load applied to the gear teeth starting from that portion, which may be a starting point of fracture during repeated fatigue. In particular, as the module size of a gear formed by injection molding increases, the void tends to increase. The existence of voids can be confirmed by cutting the gear in half in the direction perpendicular to the teeth, observing the cross section, and observing the microvoids. For example, by using a confocal microscope (for example, OPTELICS (registered trademark) H1200, manufactured by Lasertec Corporation). You can check the size of the microvoids. The upper limit of the maximum size of the void (defined in the present disclosure as the maximum value of the equivalent circle diameter of the void observed in the entire cross section of the resin gear) is preferably 2.0 μm, more preferably 1 μm. 0.0 μm, even more preferably 0.5 μm, most preferably 0.4 μm. The void is preferably absent, and even if it is present, its maximum size is preferably small. From the viewpoint of practical durability, for example, the maximum size of the void may be 0.01 μm or more. .

The number of voids in the resin gear is preferably as small as possible, and is preferably 10 or less, more preferably 8 or less, and still more preferably 5 or less per 100 mm ^{2 of the} cross section. From the viewpoint of practical durability, the number of voids may be, for example, one or more per 100 mm ^{2 of the} cross section.

≫Change in water absorption size≫
In resin gears, the water absorption dimensional change (hereinafter referred to as equilibrium water absorption) when water is absorbed in an equilibrium state (exposure to hot water at 80 ° C. for 24 hours and then holding at 80 ° C. and a relative humidity of 57% for 120 hours). (Also referred to as dimensional change) is preferably 3% or less. In an actual use environment, a smaller dimensional change is less likely to apply a large load (stress concentration) to a specific tooth of the gear, and the durability is easily improved. The upper limit of the equilibrium water absorption dimensional change is preferably 3%, more preferably 2%, still more preferably 2.5%, and most preferably 1%. The lower limit of the equilibrium water absorption dimensional change is not particularly limited, but may be, for example, 0.5% from the viewpoint of practical durability.

≪Torque≫
Since the resin gear of the present embodiment exhibits excellent durability even in a use environment where the torque is large, in one aspect, the resin gear is used at a torque of 3 N / m or more. The upper limit of the torque when the resin gear of the present embodiment is used is preferably 25 N / m, more preferably 20 N / m, and even more preferably 15 N / m from the viewpoint of durability. The lower limit of the torque is preferably 5 N / m, more preferably 10 N, from the viewpoint of obtaining a good durability advantage of the resin gear of the present embodiment.

≪Operating speed≫
The resin gear of the present embodiment can be preferably applied to a drive source whose operating rotation speed is 100 rpm or more. Therefore, one embodiment of the present disclosure provides a gear driver including the resin gear of the present disclosure and the drive source of the present disclosure. The durability of a gear greatly varies depending on the operating speed of a drive source to which the gear is applied, and the gear tends to deteriorate under an operating environment with a high operating speed. The resin gear of the present embodiment also exhibits excellent performance when applied to a drive source with a higher operating speed. The drive source is typically a motor. The upper limit of the operating rotation speed of the drive source is preferably 10,000 rpm, more preferably 5000 rpm, even more preferably 3000 rpm, and most preferably 2000 rpm. The lower limit of the operating rotational speed is not particularly limited, but is preferably, for example, 10 rpm, 100 rpm, 300 rpm, or 800 rpm from the viewpoint of obtaining a good durability advantage of the resin gear of the present embodiment.

≪Module≫
The resin gear of the present embodiment may have a module of 0.5 or more. The module is a value obtained by dividing the reference circle diameter of the gear by the number of teeth, and represents the size of the gear. The durability of the gear greatly varies depending on the size of the module. The resin gear of the present embodiment exhibits excellent performance over a wide range of module designs. The upper limit of the module is preferably 5.0, more preferably 3.0, even more preferably 2.0, and most preferably 1.0. The lower limit of the module is not particularly limited, but is preferably, for example, 0.5 from the viewpoint of obtaining a good durability advantage of the resin gear of the present embodiment.

≪Linear expansion coefficient≫
Since the resin gear of this embodiment includes (B) cellulose nanofiber having an average fiber diameter of 1000 nm or less, it is possible to exhibit a lower linear expansion property than a conventional resin gear. Specifically, it is preferable that the linear expansion coefficient in the temperature range of 0 ° C. to 60 ° C. of the resin composition which is a constituent material of the resin gear is 60 ppm / K or less. The coefficient of linear expansion is more preferably 50 ppm / K or less, still more preferably 45 ppm / K or less, and most preferably 35 ppm / K or less. The lower limit of the linear expansion coefficient is not particularly limited, but is preferably, for example, 5 ppm / K, and more preferably 10 ppm / K, from the viewpoint of ease of production.

製造 Method of manufacturing resin gears≫
The resin gear of the present embodiment includes, for example, a resin composition including (A) 100 parts by mass of the thermoplastic resin described above and (B) 1 to 50 parts by mass of cellulose nanofiber having an average fiber diameter of 1000 nm or less. It can be manufactured by melting and kneading the product and molding it into a specific shape.

  The apparatus for producing the resin composition is not particularly limited, and a generally used kneader can be used. The kneading machine is not limited to the following, but for example, a single-screw or multi-screw kneading extruder, a roll, a Banbury mixer, or the like may be used. Among them, a twin-screw extruder equipped with a decompression device and a side feeder device is preferable.

  Using these kneaders, it is possible to mold the resin composition into various shapes. Various shapes such as a resin pellet, a sheet, a fiber, a plate, and a bar are exemplified, and the resin pellet is more preferable because of easiness of post-processing and transportation. Preferable pellet shapes at this time include a round shape, an elliptical shape, and a columnar shape. The shape of the pellet varies depending on the cutting method used during extrusion. For example, pellets cut by a cutting method called underwater cut are often round, and pellets cut by a cutting method called hot cut are often round or elliptical, and a strand cut and The pellets cut by the so-called cutting method often have a columnar shape. In the case of a round pellet, the preferred size is 1 mm or more and 3 mm or less as a pellet diameter. Further, in the case of a cylindrical pellet, a preferred diameter is 1 mm or more and 3 mm or less, and a preferred length is 2 mm or more and 10 mm or less. The above-mentioned diameter and length are desirably not less than the lower limit from the viewpoint of operation stability during extrusion, and desirably not more than the upper limit from the viewpoint of biting into a molding machine in post-processing.

  The resin composition (for example, resin pellets) obtained by the above method is charged into an injection molding machine equipped with a mold having a desired gear shape, and is molded, whereby a molded product having a desired gear shape can be obtained. I can do it. Further, for example, a resin pellet is put into an extrusion molding machine, and a round bar is extruded, whereby a round bar-shaped molded body can be obtained. By cutting this round bar into a desired gear shape, a molded body having a desired gear shape can be obtained. These are easy for those skilled in the art. A more preferred molding method is injection molding. According to the above-described method, by controlling the mold surface temperature, the injection speed, the holding pressure, and the like, voids are less likely to be generated even in a thick molded product. In a typical embodiment, the resin gear is a thick molded body having a tooth width dimension of, for example, 2 to 50 mm.

≪Application≫
The resin gear of the present embodiment is excellent in mechanical strength, durability and quietness, and thus can be suitably used for various applications. In particular, as the gear, although not limited to the following, for example, helical gear, spur gear, internal gear, rack gear, helical gear, straight bevel gear, helical bevel gear, spiral bevel gear, crown gear, Face gears, screw gears, worm gears, worm wheel gears, hypoid gears, and Novikov gears. Further, the above-mentioned helical gear, spur gear, etc. may be a single gear, a two-stage gear, or a combination gear having a structure in which a drive motor is combined in multiple stages to reduce rotation without uneven rotation.

  Examples of parts that are preferably used for such gears include, but are not limited to, cams, sliders, levers, arms, clutches, felt clutches, idler gears, pulleys, rollers, rollers, rollers, key stems, key tops, shutters, reels, and shafts. , Joints, shafts, bearings, and guides. In addition, outsert molded resin parts, insert molded resin parts, chassis, trays and side plates are also included.

  Specific applications of the resin gear of the present embodiment include, but are not limited to, mechanical components for office automation equipment, mechanical components for cameras or video equipment, mechanical components for music, video or information equipment, and communication equipment. Mechanical parts, electrical equipment mechanical parts, electronic equipment mechanical parts, automobile mechanical parts (door peripheral parts, seat peripheral parts, air conditioner peripheral parts), bicycle mechanical parts (drive motor transmission, etc.), switch parts, Stationary mechanism components, mechanical components of residential equipment, mechanical components of vending machines, mechanical components of sports, leisure and recreation-related equipment, and mechanical components of industrial equipment.

  In addition, the resin gear of the present embodiment can be applied to automobiles and electric vehicles in general, from the viewpoint of maintaining remarkably excellent durability and quietness as compared with conventional resin gears. Examples of the electric vehicle include, but are not limited to, senior four-wheeled vehicles, motorcycles, and electric motorcycles.

  The resin gear of the present embodiment is preferably used by applying grease. Thereby, durability and quietness can be improved greatly.

The present invention will be further described based on examples, but the present invention is not limited to these examples.
≪Raw materials and evaluation method≫
Hereinafter, the used raw materials and the evaluation method will be described.

<< (A) thermoplastic resin >>
(A-1) PA6 UBE nylon 1013B manufactured by Ube Industries, Ltd.
(A-2) POM Tenac TM 4520 manufactured by Asahi Kasei Corporation

<< (B) Cellulose nanofiber whose average fiber diameter is 1000 nm or less >>
(B-1) Cellulose A
After cutting the linter pulp, the purified pulp from which the hemicellulose portion was removed was heated in a hot water of 120 ° C. or more for 3 hours using an autoclave, and the solid content was reduced to 1.5% by weight in pure water. After the fibers were highly shortened and fibrillated by beating as described above, the fibers were fibrillated at the same concentration using a high-pressure homogenizer (operating pressure: processing 10 times at 85 MPa) to obtain fibrillated cellulose. Here, in the beating process, using a disc refiner, a beating blade having a high cutting function (hereinafter referred to as a cutting blade) is used for 2.5 hours, and then a beating blade having a high defibrating function (hereinafter referred to as a defibrating blade) is used. The mixture was further beaten for 2 hours to obtain cellulose A.

(B-2) Cellulose B
After cutting the linter pulp, the purified pulp from which the hemicellulose portion was removed was heated in a hot water of 120 ° C. or more for 3 hours using an autoclave, and the solid content was reduced to 1.5% by weight in pure water. After the fibers were highly shortened and fibrillated by beating as described above, the fibers were fibrillated at the same concentration using a high-pressure homogenizer (operating pressure: processing 10 times at 85 MPa) to obtain fibrillated cellulose. Here, in the beating process, a disc refiner is used, and after processing for 4 hours with a beating blade having a high cutting function (hereinafter, referred to as a cutting blade), using a beating blade having a high defibrating function (hereinafter, referred to as a defibrating blade). Beating was further performed for 4 hours to obtain cellulose B.

(B-3) Cellulose C
WO 2017/159823 [0108] Cellulose C was obtained by the method described in Example 1.

<(B) Degree of polymerization of cellulose nanofiber>
It was measured by the reduced specific viscosity method using a copper ethylenediamine solution specified in the crystalline cellulose confirmation test (3) of “14th Revised Japanese Pharmacopoeia” (published by Hirokawa Shoten).

<(B) Crystal Form and Crystallinity of Cellulose Nanofiber>
Using an X-ray diffractometer (manufactured by Rigaku Corporation, a multipurpose X-ray diffractometer), a diffraction image was measured by a powder method (normal temperature), and the crystallinity was calculated by a Segal method. The crystal form was also measured from the obtained X-ray diffraction image.

<(B) L / D of cellulose nanofiber>
(B) Cellulose nanofiber was made into a pure water suspension at a concentration of 1% by mass, and a high shear homogenizer (manufactured by Nippon Seiki Co., Ltd., trade name "Excel Auto Homogenizer ED-7", processing condition: rotation speed: 15,000 rpm) × 5 minutes), the aqueous dispersion was diluted with pure water to 0.1 to 0.5% by mass, cast on mica, and air-dried, and measured with an atomic force microscope (AFM). Then, the ratio (L / D) when the major axis (L) and the minor axis (D) were obtained was calculated as an average value of 100 to 150 particles.

<(B) Average fiber diameter of cellulose nanofiber>
(B) Using a cellulose nanofiber having a solid content of 40% by mass, in a planetary mixer (trade name “5DM-03-R”, manufactured by Shinagawa Kogyo KK, trade name: hook type stirring blade) at 126 rpm at room temperature. Kneaded under pressure for 30 minutes. Next, a pure water suspension having a solid content of 0.5% by mass was prepared, and a high shear homogenizer (manufactured by Nippon Seiki Co., Ltd., trade name "Excel Auto Homogenizer ED-7"), processing conditions: 15,000 rpm × 5 minutes), and centrifuged (Kubota Shoji Co., Ltd., trade name “6800 type centrifuge”, rotor type RA-400), processing conditions: centrifuged at 39200 m ² / s for 10 minutes, and supernatant Was collected, and the supernatant was centrifuged at 116,000 m ² / s for 45 minutes.) Using the supernatant liquid after centrifugation, the volume obtained by a laser diffraction / scattering particle size distribution analyzer (trade name “LA-910”, manufactured by HORIBA, Ltd., ultrasonic treatment for 1 minute, refractive index 1.20). The cumulative 50% particle diameter (volume average particle diameter) in the frequency particle size distribution was measured, and this value was defined as the average fiber diameter.

<< (C) surface modifier >>
(C-1) Aoki Yushi Kogyo Co., Ltd. Braunon RCW-20 (CAS No. 61788-85-0, static surface tension 42.4 mN / m, dynamic surface tension 52.9 mN / m)
Boiling point above 100 ° C under normal pressure.
(C-2) Superflex 300 manufactured by Daiichi Kogyo Co., Ltd.
(C-3) PEG 20000 manufactured by Sanyo Chemical Industries, Ltd.

<Measurement of static surface tension>
Using each surfactant, the static surface tension was measured by the Wilhelmy method using an automatic surface tension measuring device (trade name “CBVP-Z”, manufactured by Kyowa Interface Science Co., Ltd., attached glass cell). Since each surfactant used in Examples and Comparative Examples was liquid at room temperature, it was charged into a stainless steel petri dish attached to the apparatus so that the height from the bottom to the liquid surface was 7 mm to 9 mm, and 25 ° C. ± It was measured after adjusting the temperature to 1 ° C., and determined by the following equation. γ = (P-mg + shρg) / Lcos θ. Here, P: balancing force, m: plate mass, g: gravitational constant, L: plate perimeter, θ: contact angle between plate and liquid, s: plate cross-sectional area, h: liquid (to the point where force is balanced) Depth from the surface, ρ: density of liquid (1 was used because the density of the surfactant used in Examples and Comparative Examples was 1 ± 0.4 g / mL).
A solid at room temperature was heated to a temperature equal to or higher than the melting point and melted, then adjusted to a temperature of the melting point + 5 ° C., and the surface tension was measured by the Wilhelmy method described above.

<Measurement of dynamic surface tension>
Using a surfactant, a dynamic surface tensiometer (manufactured by Eiko Seiki Co., Ltd., product name: ThetaScience t-60 type), a probe (capillary TYPE I (manufactured by Peak Resin), single mode), air bubbles were obtained by the maximum bubble pressure method. The dynamic surface tension was measured at a generation period of 10 Hz, and each surfactant used in Examples and Comparative Examples was dissolved or dispersed in ion-exchange water with 5% by mass to prepare a measurement solution, and 100 mL of the solution or dispersion was prepared. Was charged into a glass beaker having a capacity of 100 mL, the temperature was adjusted to 25 ° C. ± 1 ° C., and the measured value was used.The dynamic surface tension was determined by the following equation: σ = ΔP · r / 2, where σ: dynamic surface tension, ΔP: pressure difference (maximum pressure−minimum pressure), r: capillary radius.

<< (D) metal ion component >>
(D-1) Copper (I) iodide Product name Wako Pure Chemical Industries, Ltd. Copper (I) iodide
(D-2) Potassium iodide Product name, manufactured by Wako Pure Chemical Industries Potassium iodide (d-3) Calcium stearate Product name, manufactured by Sakai Chemical Industry Co., Ltd. Calcium stearate

{(E) Sliding agent component}
(E-1) Product name Uniside 700 (melting point 110 ° C) manufactured by Wax Baker Petrolite Co., Ltd.
(E-2) Ethylenebisstearylamide Lion Product name Armowax EBS (melting point 145 ° C)

≪ (F) glass fiber≫
(F-1) Average fiber diameter φ10 μm, manufactured by Asahi Fiberglass Co., Ltd.
(F-2) Average fiber diameter φ13 μm NEC Electronics Glass Co., Ltd. product name ECS03T-651P

≪Manufacturing conditions≫
Using a twin screw extruder (Toshiba Machine Co., Ltd. TEM-26SS extruder (L / D = 48, with vent), set the cylinder temperature to 260 ° C for polyamide-based materials and 200 ° C for polyoxymethylene-based materials. Then, the components (A) and (B), and optionally the components (C), (D) and additional components are mixed at once and fed from a main throat section of an extruder through a fixed-quantity feeder to obtain an extrusion rate of 15 kg / hour. The resin kneaded material was extruded into strands under the conditions of a screw rotation number of 250 rpm, rapidly cooled in a strand bath, and cut with a strand cutter to obtain a pellet-shaped resin composition.

≪Molding conditions / multipurpose test specimen≫
A multi-purpose test piece conforming to ISO294-3 was molded from the pellet-shaped resin composition obtained under the above-described production conditions using an injection molding machine.
Polyamide-based material: Conditions in accordance with JIS K6920-2 Polyoxymethylene-based material: Conditions in accordance with JIS K7364-2 Since polyamide-based materials undergo changes due to moisture absorption, they are stored in an aluminum moisture-proof bag immediately after molding. Suppressed moisture absorption.

≪Evaluation conditions and multipurpose test pieces≫
The tensile yield strength and tensile elongation at break of the multipurpose test piece obtained in the above {Molding conditions / multipurpose test piece} were measured in accordance with ISO527, and the flexural modulus was measured in accordance with ISO179.

≪Aging test≫
An exposure test of the multipurpose test piece was performed in a 150 ° C. atmosphere using GPH-102 manufactured by Espec Corporation. The sample after exposure was stored in an aluminum bag, and the tensile yield strength was measured according to ISO527. The strength retention at this time was evaluated based on the multi-purpose test piece on day 0 of exposure as a reference (100%), and the number of days that the tensile yield strength maintained 80% was evaluated.

≪Wear amount≫
For the multi-purpose test piece obtained in the above {Molding conditions / multi-purpose test piece}, a reciprocating friction and wear tester (AFT-15MS type, manufactured by Toyo Seimitsu Co., Ltd.) and a SUS304 test piece (ball having a diameter of 5 mm) as a mating material were used. A sliding test was performed at a linear velocity of 50 mm / sec, a reciprocating distance of 50 mm, a temperature of 23 ° C., and a humidity of 50%. The value at the end of the following test conditions was adopted as the coefficient of friction. The amount of abrasion was measured using a confocal microscope (OPTELICS (registered trademark) H1200, manufactured by Lasertec Corporation). The wear cross-sectional area was an average of the values measured at n = 4, and rounded off to the first decimal place. The measurement was made at a position 12.5 mm from the end of the wear mark, and the measurement was performed at equal intervals. The lower the numerical value of the wear cross-sectional area, the better the wear characteristics.
Test conditions: 9.8N load, 10,000 reciprocations

≫Change in water absorption size≫
The multi-purpose test piece obtained in the above {Molding conditions / multi-purpose test piece} was brought into an equilibrium state (exposed in hot water at 80 ° C. for 24 hours, and then kept at 80 ° C. and a relative humidity of 57% for 120 hours). Thereafter, the outer diameter before and after water absorption was measured with a digital precision caliper manufactured by Mitutoyo Corporation, and the equilibrium water absorption dimension change (%) = (dimension after water absorption) / (dimension before water absorption) × 100 was calculated. "Before water absorption" means a state in which a multipurpose test piece immediately after molding is stored in an aluminum bag and returned to room temperature.

≪Linear expansion coefficient≫
From the central part of the multi-purpose test piece obtained in the above {Molding conditions / multi-purpose test piece}, cut out a rectangular parallelepiped sample having a length of 4 mm, a width of 4 mm, and a length of 10 mm with a precision cut-saw, and a measurement temperature range of -10 to 80 ° C. The expansion coefficient between 0 ° C and 60 ° C was calculated in accordance with ISO 11359-2.

≪Molding conditions / Gear molding A≫
Using the injection molding machine (trade name “α50i-A injection molding machine”) manufactured by FANUC CORPORATION, the cylinder temperature of the pellet-shaped resin composition obtained under the above manufacturing conditions was set to 250 ° C. for the polyamide-based material. The polyoxymethylene-based material was subjected to injection molding under the conditions of 190 ° C., a mold temperature of 80 ° C., an injection pressure of 120 MPa, an injection time of 10 seconds, and a cooling time of 60 seconds, module 0.8, number of teeth 50, tooth width 5 mm. Spur gear was obtained. In addition, about the polyamide type | system | group material, since it changes by moisture absorption, it was stored in the aluminum moistureproof bag immediately after molding, and moisture absorption was suppressed. At this time, two types of mirror finish and grain finish were used as the mold surface. The arithmetic average surface roughness Ra of the mirror-finished mold surface was 0.03, and the arithmetic average surface roughness Ra of the grain-finished mold surface was 2.0.

≪Molding conditions / Gear molding B≫
Using the injection molding machine (trade name “α50i-A injection molding machine”) manufactured by FANUC CORPORATION, the cylinder temperature of the pellet-shaped resin composition obtained under the above manufacturing conditions was set to 250 ° C. for the polyamide-based material. Injection molding was carried out under the conditions of a polyoxymethylene-based material at 190 ° C., a mold temperature of 80 ° C., an injection pressure of 120 MPa, an injection time of 10 seconds and a cooling time of 60 seconds, module 0.8, number of teeth 50, tooth width 12 mm. Spur gear was obtained. In addition, about the polyamide type | system | group material, since it changes by moisture absorption, it was stored in the aluminum moistureproof bag immediately after molding, and moisture absorption was suppressed. At this time, two types of mirror finish and grain finish were used as the mold surface. The arithmetic average surface roughness Ra of the mirror-finished mold surface was 0.03, and the arithmetic average surface roughness Ra of the grain-finished mold surface was 2.0.

≪Molding conditions / Gear molding C≫
Using the injection molding machine (trade name “α50i-A injection molding machine”) manufactured by FANUC CORPORATION, the cylinder temperature of the pellet-shaped resin composition obtained under the above manufacturing conditions was set to 250 ° C. for the polyamide-based material. Injection molding was carried out under the conditions of a polyoxymethylene-based material at 190 ° C., a mold temperature of 80 ° C., an injection pressure of 120 MPa, an injection time of 10 seconds and a cooling time of 60 seconds, module 1.5, number of teeth 50, tooth width 12 mm. Spur gear was obtained. In addition, about the polyamide type | system | group material, since it changes by moisture absorption, it was stored in the aluminum moistureproof bag immediately after molding, and moisture absorption was suppressed. At this time, two kinds of mold surfaces, mirror finish and grain finish, were used. The arithmetic average surface roughness Ra of the mirror-finished mold surface was 0.03, and the arithmetic average surface roughness Ra of the grain-finished mold surface was 2.0.

≪Annealing treatment≫
The spur gears obtained in the above {Molding condition / Gear molding A}, {Molding condition / Gear molding B}, {Molding condition / Gear molding C} were applied at 130 ° C. for 1 hour (A condition) for polyamide-based materials. The polyoxymethylene-based material was heat-treated at 140 ° C. for 5 hours (condition B) using GPH-102 manufactured by Espec Corporation.

{Arithmetic average surface roughness of gear sliding surface Sa}
Using the spur gears obtained in the above {Molding condition / Gear molding A}, {Molding condition / Gear molding B}, {Molding condition / Gear molding C}, or the spur gears annealed by the previous {Annealing treatment} Then, five arbitrary teeth are cut out per one spur gear, and the surface roughness (arithmetic average surface roughness Sa) of 100 μm square area at the center of the surface of each tooth in the in-plane direction is based on ISO25178. Was measured. Further, a number average value was calculated using Sa of the five measured teeth (that is, n = 5 for each spur gear and n = 1 measurement for each tooth). At this time, the surface roughness was measured using a confocal microscope (OPTELICS (registered trademark) H1200, manufactured by Lasertec Co., Ltd.).

≪Gear durability test≫
The spur gears obtained in {Molding Condition / Gear Molding A}, {Molding Condition / Gear Molding B} and {Molding Condition / Gear Molding C} are the same material as a gear durability tester manufactured by Toshiba Machine Co., Ltd. The gears were knitted and installed. One of the gears was the drive side and the other was the driven side. Next, the gear on the driving side was rotated under the following conditions, and the time until the gear was broken (durable time) was measured.
Durability test A: torque 5 N / m, rotation speed 1000 rpm
Durability test B: torque 5 N / m, rotation speed 2000 rpm
Durability test C: torque 15 N / m, rotation speed 1000 rpm
Durability test D: torque 20 N / m, rotation speed 1000 rpm
Further, in the durability test A, the water absorption dimensional change was measured in the same manner as the above {water absorption dimensional change}.

≫Evaluation of quietness≫
The quietness was evaluated at the time of {gear durability test}. A microphone is installed at a position 50 mm away from the shaft of the gear on the drive side, and after the start of the gear durability test, the noise level is measured with a sound level meter (based on JIS C1502) for 1 minute from 60 minutes after. evaluated.
：: Maximum noise level is less than 70 dB 最大: Maximum noise level is 70 dB or more and less than 75 dB Δ: Maximum noise level is 75 dB or more and less than 85 dB ×: Maximum noise level is 85 dB or more

≪Molding conditions and round gear molding≫
The pellet-shaped resin composition obtained under the above manufacturing conditions is supplied to a take-off device and a 30 mm single-shaft solidifying extruder having a water cooling zone in an extruder die, and the cylinder temperature is set to 280 ° C. for the polyamide-based material. The temperature of the polyoxymethylene-based material was set to 230 ° C., and a round bar having a diameter of 60 mm was solidified and extruded. At this time, the take-off device was driven toward the die so that the extrusion speed was 3 mm / min in order to suppress sink marks and microvoids in the extruded product. The obtained round bar was cut and formed into the same gear as in {Forming conditions / Gear forming A}. In addition, about the polyamide type | system | group material, since it changes by moisture absorption, it was stored in the aluminum moistureproof bag immediately after molding, and moisture absorption was suppressed.

≫Observation of voids≫
The gear obtained in {Molding Condition / Gear Molding A} is an injection molding gear, the gear obtained in {Molding Condition / Round Bar Gear Molding} is a round bar cutting gear, and each gear is perpendicular to the teeth. The wafer was cut in half in the direction, and the cross section was observed to confirm the presence or absence of microvoids. For observation, a confocal microscope (OPTELICS (registered trademark) H1200, manufactured by Lasertec Co., Ltd.) was used. For the microvoids observed, the size of the region where the voids were generated was measured and expressed as a numerical value using the diameter of the circle-equivalent diameter of the generated region. The maximum value of the observed voids was recorded.

[Examples 1 to 12 and Comparative Examples 1 to 5]
A polyamide resin composition was obtained by the methods described in Tables 2 and 3. These were molded and evaluated according to the evaluation method described above. The results are shown in Tables 2 and 3.

[Examples 13 to 16 and Comparative Examples 6 to 9]
A polyacetal resin composition was obtained by the method shown in Table 4. These were molded and evaluated according to the evaluation method described above. Table 4 shows the results.

  The resin gear of the present invention is particularly useful in the field of automobile mechanism parts that require durability and quietness.

Claims (19)

  (A) a thermoplastic resin, and (B) a cellulose nanofiber having an average fiber diameter of 1000 nm or less, and an arithmetic average surface roughness Sa of a sliding surface with another gear tooth is 3.0 μm or less, A resin gear used at a torque of 3 N / m or more.   (A) a thermoplastic resin, and (B) a cellulose nanofiber having an average fiber diameter of 1000 nm or less, and an arithmetic average surface roughness Sa of a sliding surface with another gear tooth is 3.0 μm or less. Gear made of resin.   3. The method according to claim 1, wherein a dimensional change in water absorption when exposed to hot water at 80 ° C. for 24 hours, and then held for 120 hours under a condition of 80 ° C. and a relative humidity of 57% is 3% or less. The resin gear described.   The resin gear according to any one of claims 1 to 3, wherein a maximum size of a void in the resin gear is 1.0 m or less.   The resin gear according to any one of claims 1 to 4, which is used at a torque of 5 N / m or more.   The resin gear according to any one of claims 1 to 5, which is used at a torque of 10 N / m or more.   (A) the thermoplastic resin is at least one resin selected from the group consisting of polyolefin resins, polyamide resins, polyester resins, polyacetal resins, polyacrylic resins, polyphenylene ether resins, and polyphenylene sulfide resins; The resin gear according to any one of claims 1 to 6, wherein   The resin gear according to claim 7, wherein (A) the thermoplastic resin is at least one resin selected from the group consisting of polyamide and polyacetal.   The resin gear according to any one of claims 1 to 8, further comprising (C) a surface modifier.   The resin gear according to claim 9, wherein the number average molecular weight of the surface modifier (C) is from 200 to 10,000.   The resin gear according to claim 9 or 10, wherein the resin gear comprises (C) a surface modifier in an amount of 1 to 50 parts by mass based on 100 parts by mass of the cellulose nanofiber (B).   The resin gear according to any one of claims 1 to 11, further comprising (D) a metal ion component.   The resin gear according to claim 12, wherein (D) the metal ion component is contained in an amount of 0.005 to 5 parts by mass based on 100 parts by mass of the thermoplastic resin (A).   The resin gear according to any one of claims 1 to 13, further comprising (E) a sliding agent component.   15. The resin gear according to claim 14, comprising (E) a sliding agent component in an amount of 0.01 to 5 parts by mass based on 100 parts by mass of the thermoplastic resin (A).   The resin gear according to claim 14 or 15, wherein the melting point of the sliding agent component (E) is 40 to 150 ° C.   The resin gear according to any one of claims 1 to 16, wherein the number of modules is 2.0 or less.   A gear drive, comprising: the resin gear according to any one of claims 1 to 17; and a drive source that is a motor having an operating speed of 800 rpm or more.   19. The gear drive according to claim 18, wherein the motor is a motor having an operating rotation speed of 10,000 rpm or less.