JP2020007492A - Cellulose-containing resin composition - Google Patents

Abstract

To provide a resin composition which is excellent in wear resistance and vibration fatigue characteristics in practical applications while being imparted with sufficient mechanical characteristics and thermal characteristics.SOLUTION: The resin composition contains (A) 100 pts.mass of a thermoplastic resin, (B) 1-200 pts.mass of a nanocellulose having an average fiber diameter of 1,000 nm or less, (C) 0.1-200 pts.mass of a surface modifier, and (D) 0.1-10,000 mass ppm of an aprotic organic solvent having a boiling point of 100°C or higher.SELECTED DRAWING: None

Description

  The present invention relates to a resin composition containing cellulose.

  Since thermoplastic resins are light and have excellent processing characteristics, they are 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, and clay has a problem that the weight of the obtained resin molded article is increased due to the high specific gravity of these fillers. There is. Therefore, in recent years, cellulose having a low environmental load has been used as a new reinforcing material for resin.

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. cm ³ ), which is by far the lightest material.

  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 a 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 alleviate the hydrogen bond caused by 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 (ie, less than 1 μm)) in the resin. Therefore, there have been problems such as a low rate of improvement in mechanical strength and weakness to repeated vibration fatigue.

  In order to utilize these CNFs as fillers, CNF production methods have been proposed. For example, Patent Literature 1 describes a technique in which cellulose and an aprotic organic solvent are defibrated by a kneader. Patent Document 2 discloses a production technique for drying cellulose nanofibers in the presence of an organic solvent and water.

JP 2018-35466 A WO 2017/11116

  In Patent Document 1, the energy of fibrillation is reduced by introducing cellulose and an organic solvent having an affinity for cellulose into a kneader without using water. Furthermore, surface treatment is performed by adding a compound having a fluorene skeleton and defibrating. However, in this technique, the amount of the organic solvent used for cellulose is large, and the environmental load is large. Further, Patent Document 1 does not mention improvement in the strength of the composition by dispersing the cellulose nanofibers when the resin composition is used, and practical characteristics (wear resistance, vibration fatigue characteristics).

  Patent Document 2 discloses a method for treating a surface of a carboxylated cellulose nanofiber or a cationized cellulose nanofiber, and improving the water removal efficiency by precipitating these cellulose nanofibers with an organic solvent, and returning to water again. A method for expressing similar dispersibility when dissolved is described. Patent Document 2 further discloses that addition of carboxymethyl cellulose further improves dispersibility. However, the technique of Patent Document 2 has the purpose of removing water and then dispersing it in water again. The document describes that the dispersion of cellulose nanofibers as a resin composition improves the strength of the composition, No reference is made to practical properties (wear resistance, vibration fatigue properties).

  Therefore, there is a problem that the technology described in these patent documents is not suitable for practical use. That is, at present, a sufficient amount of cellulose is finely dispersed in the resin composition to exhibit the desired mechanical properties of the resin molded article, and high mechanical properties and thermal properties (particularly, reduced thermal expansion) are obtained. In addition, a composition having excellent wear resistance (particularly wear resistance during sliding) and excellent vibration fatigue properties has not been obtained.

  An object of the present invention is to solve the above problems and to provide a resin composition having excellent mechanical properties and thermal properties to a resin molded article, and excellent in wear resistance and vibration fatigue properties in actual use. I do.

  The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, the thermoplastic resin contains a necessary amount of cellulose, and further contains a specific surface modifier, and a specific aprotic solvent. The present inventors have found that a resin composition containing the same can solve the above-mentioned problems, and have accomplished the present invention.

That is, the present invention includes the following embodiments.
[1] (A) 100 parts by mass of a thermoplastic resin, (B) 1 to 200 parts by mass of a cellulose nanofiber having an average fiber diameter of 1000 nm or less, and (C) 0.1 to 200 parts by mass of a surface modifier. And (D) a resin composition containing 0.1 to 10000 ppm by mass of an aprotic organic solvent having a boiling point of 100 ° C or higher.
[2] (A) The thermoplastic resin is a polyolefin resin, a polyamide resin, a polyester resin, a polyacetal resin, a polyacrylic resin, a polyphenylene ether resin, a polyphenylene sulfide resin, and a mixture of any two or more thereof. The resin composition according to the above aspect 1, which is selected from the group consisting of:
[3] The resin composition according to the above aspect 1 or 2, wherein the (D) aprotic organic solvent is water-soluble.
[4] The resin composition according to any one of Aspects 1 to 3, wherein the aprotic organic solvent has a relative dielectric constant of 3 to 80 at 25 ° C.
[5] The resin composition according to any one of the above aspects 1 to 4, wherein the aprotic organic solvent (D) has a boiling point of 110 to 290 ° C.
[6] The resin composition according to any of the above aspects 1 to 5, wherein the (C) surface modifier contains a hydrophilic segment and a hydrophobic segment in the molecule.
[7] The resin composition according to any of the above aspects 1 to 6, which comprises (C) a surface modifier in an amount of 1 to 100% by mass based on (B) the cellulose nanofiber.
[8] The resin composition according to any one of Aspects 1 to 7, wherein the surface modifier has a cloud point of 20 ° C or higher.
[9] The resin composition according to any one of the above aspects 1 to 8, wherein the ethylene glycol unit in the molecule of the surface modifier (C) is 50% by mass or more of all units.
[10] A molded article formed from the resin composition according to any one of the above aspects 1 to 9.

  ADVANTAGE OF THE INVENTION According to this invention, while providing sufficient mechanical and thermal characteristics to a resin molded object, the resin composition which was excellent in abrasion resistance and vibration fatigue characteristics in actual use is provided.

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

<< (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 the peak 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 preferable to use a sample which is once heated to a temperature condition of not less 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 apparatus 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 for 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 acid modified product thereof, copolymer of (ethylene and / or propylene) and (unsaturated carboxylic acid and / or unsaturated carboxylic acid ester), (ethylene And / or propylene) and (olefinically 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 Copolymer rubber, chlorosulfonated polyethylene, acrylic rubber, epichlorohydrin rubber, polysulfide rubber, silicone rubber, fluorine rubber, urethane rubber, polyvinyl chloride, polystyrene, polyacrylic acid ester, polymethacrylic acid and other acrylic and acrylonitrile 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. Further, those obtained by modifying the above-mentioned 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 at least one resin selected from the group consisting of polyphenylene sulfide resin, particularly polyamide One or more resins selected from the group consisting of a base resin and a polyacetal 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 the 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 a resin is heated to a melting point or higher and melt-kneaded in the presence / absence of a peroxide. As the polyolefin resin to be acid-modified, all of the above-mentioned polyolefin resins can be used, but 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 interfacial strength with cellulose, the lower limit is preferably greater than or equal to the lower 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, nonanedioic acid, decane diacid, benzene-1,2-dicarboxylic acid, 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 resin, the ratio of the carboxyl terminal group to all terminal groups ([COOH] / [all terminal groups]) is 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 preferably 0.30 or more from the viewpoint of dispersibility of (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 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 cyclohexanecarboxylic acid; aromatic monocarboxylic acids such as benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, and phenylacetic acid; A carboxylic acid; 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 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, 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. The use of the polyamide resin having an intrinsic viscosity in a preferred range, and particularly preferred range among them, significantly enhances fluidity in a mold at the time of injection molding of the 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 obtaining this viscosity is to measure ηsp / c of several measurement solvents having different concentrations in 96% concentrated sulfuric acid under a temperature condition of 30 ° C., 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), and 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-based resin, the terminal group can be freely changed depending on the monomer ratio at the time of polymerization and the presence or absence and amount of the terminal stabilizer, but the ratio of the carboxyl terminal group to the total terminal group of the polyester-based resin can be freely changed. ([COOH] / [all terminal groups]) is preferably 0.30 to 0.95. The lower limit of the carboxyl end 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 preferably 0.30 or more from the viewpoint of dispersibility of (B) cellulose nanofiber in the composition, and 0.95 or less from the viewpoint of the color tone of the obtained composition. Is desirable.

  The preferred polyacetal resin as a thermoplastic resin is a homopolyacetal using formaldehyde as a raw material and a copolyacetal containing trioxane as a main monomer and, for example, 1,3-dioxolane as a comonomer component, and both can be used. 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%, further 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 having an average fiber diameter of 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, and for example, cellulose nanofiber using cellulose pulp as a raw material or one or more kinds of modified 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. (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 molded product. The average fiber diameter is preferably smaller, but from the viewpoint of processability, 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 L / D lower limit of the cellulose nanofiber is preferably 30, more preferably 40, more preferably 50, and even more preferably 100. The upper limit is not particularly limited, but is preferably 10,000 or less from the viewpoint of handling. 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 are determined by using a water-dispersed liquid 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 nanofibers in the molded product 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 washing sufficiently 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 mica 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.

  (B) Cellulose nanofibers are prepared by treating pulp or the like with hot water of 100 ° C. or more, hydrolyzing the hemicellulose portion to make it weak, and then pulverizing using a high-pressure homogenizer, a microfluidizer, a ball mill, a disk mill, or the like. It may be cellulose fibrillated by a method. In one embodiment, the (B) cellulose nanofiber may have an L / D ratio of 30 or more and is not classified as a cellulose pulp (that is, an L / D ratio of 40 or more and a fiber diameter of more than 1000 nm). .

  (B) The lower limit of L / D of the cellulose nanofiber is preferably 50, more preferably 80, more preferably 100, even more preferably 120, and most preferably 150. The upper limit is not particularly limited, but is preferably 1,000 or less from the viewpoint of handling. The L / D ratio of the (B) cellulose nanofiber is desirably within the above range, in order to exhibit good mechanical properties of the resin molded body obtained by using the resin composition of the present disclosure in a small amount.

  As the modified product of (B) cellulose nanofiber in the present disclosure, at least one modified agent selected from an esterifying agent, a silylating agent, an isocyanate compound, a halogenated alkylating agent, an alkylene oxide and / or a glycidyl compound is used. Modified ones may be mentioned.

  The esterifying agent as a modifying agent includes (B) an organic compound having at least one functional group capable of reacting with and hydroxylating a hydroxyl group on the surface of the cellulose nanofiber. 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 symmetrical 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 and halogenating 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 (B) an organic compound having at least one isocyanate group capable of reacting with a hydroxyl group on the surface of the cellulose nanofiber. Further, the isocyanate compound may be a blocked isocyanate compound capable of regenerating an isocyanate group by removing a blocking group at a specific temperature, or a dimer or trimer of polyisocyanate, or a buret-forming isocyanate. And polymethylene polyphenyl polyisocyanate (polymeric MDI). These may be commercially available reagents or products.

  Suitable 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. A cyanate compound, and the like.

  Among these, 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, phenylphenol 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 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 are exemplified.

  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.

(B) Cellulose nanofibers are obtained by dissolving the resin component in the composition in an organic or inorganic solvent capable of dissolving the resin component of the composition, separating the cellulose, washing sufficiently with the solvent, and then separating the separated cellulose. It can be confirmed by 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) that can be used in the present invention will be described in detail. (C) The surface modifier is, for example, (A) a modified polymer (for example, an acid-modified product or copolymer) of the same polymer as the thermoplastic resin, or (A) a polymer different from the thermoplastic resin. Is different from (A) thermoplastic resin. (C) The surface modifier may be added by, for example, a method of kneading the resin in an aqueous solution state. (C) The surface modifier may be a commercially available reagent or product.

  In a typical embodiment, (C) the surface modifier comprises (A) a thermoplastic resin and / or (B) a functional group capable of chemically or physically binding or interacting with the cellulose nanofiber (in the present disclosure, "Reactive functional group"). Bonds typically involve chemical bonds, such as ionic and covalent bonds, and interactions are typically due to intermolecular forces (eg, hydrogen bonds, van der Waals forces, and electrostatic attraction). Adsorption (chemical or physical adsorption). In one embodiment, the reactive functional group of the surface modifier (C) is a group that exhibits binding or adsorptivity with at least a hydroxyl group. As the reactive functional group, hydroxyl group, carboxyl group, formyl group, acyl group, amino group, azo group, azi group, imino group, carbonyl group, thiocarbonyl group, diimide group, thiol group, epoxy group, isocyanate group, Isothiocyanate group, sulfone group, cyano group, nitro group, isonitrile group, vinyl group, allyl group, alkoxy group, acid anhydride group, carbon-carbon double bond, ester bond, thioester bond, ether bond, thioether bond, disulfide Bond, amide bond, imide bond, urethane bond, and the like. One or more of these reactive functional groups can be present in the molecule.

  Among them, a hydroxyl group, a carboxyl group, a formyl group, an amino group, a carbonyl group, and an isocyanate group can be preferably used from the viewpoint of reactivity with (A) a thermoplastic resin and / or (B) cellulose nanofiber. .

  In a typical embodiment, (A) the thermoplastic resin and (C) the surface modifier differ in molecular weight and / or functional group structure. Examples of preferable combinations of (A) the thermoplastic resin and (C) the surface modifier are polyamide resin and polyurethane, polyamide resin and polyethylene glycol, polyamide resin and polyacryl, and the like.

  (C) The surface modifier may be a water-soluble polymer. Throughout the present disclosure, “water-soluble” means that 0.1 g or more is dissolved in 100 g of water at 23 ° C. (C) The structure of the surface modifier is not particularly limited, and examples thereof include a compound having a hydrophilic segment and a hydrophobic segment in the molecule, and such a compound can be water-soluble.

  (C) The hydrophilic segment of the surface modifier can improve the affinity with the surface of cellulose. On the other hand, through the hydrophilic segment, the hydrophobic segment can suppress aggregation between celluloses. Therefore, the hydrophilic segment and the hydrophobic segment need to exist in the same molecule.

  Examples of the hydrophilic segment include a segment having a polyethylene glycol, a segment including a repeating unit including a quaternary ammonium salt structure, a segment of polyvinyl alcohol, a segment of polyvinyl pyrrolidone, a segment of polyacrylic acid, a segment of carboxyvinyl polymer, and cationization. Examples include a guar gum segment, a hydroxyethyl cellulose segment, a methyl cellulose segment, a carboxymethyl cellulose segment, and a polyurethane flexible diol segment (soft segment).

  Examples of the hydrophobic segment include a segment having an alkylene oxide unit having 3 or more carbon atoms, a rigid urethane segment (hard segment) of polyurethane, an acrylic polymer, a styrene resin, a vinyl chloride resin, a vinylidene chloride resin, and a polyolefin resin. A polycondensate of an organic dicarboxylic acid having 4 to 12 carbon atoms and an organic diamine having 2 to 13 carbon atoms; a polycondensate of an ω-amino acid (for example, ω-aminoundecanoic acid) (for example, polyundecaneamide (11 nylon)) Lactam ring-opening polymers such as polycapramide (6 nylon) which is a ring-opening polymer of ε-aminocaprolactam and polylauric lactam (12 nylon) which is a ring-opening polymer of ε-aminolaurolactam. Amino acid containing lactam, polymer composed of diamine and dicarboxylic acidー, polyacetal resin, polycarbonate resin, polyester resin, polyphenylene sulfide resin, polysulfone resin, polyetherketone resin, polyimide resin, fluorine resin, hydrophobic silicone resin, melamine resin, epoxy resin And phenolic resins.

  (C) The structure of the surface modifier is not particularly limited, but when the hydrophilic segment is A and the hydrophobic segment is B, the AB type block copolymer, the ABA type block copolymer, and the BAB type block copolymer Polymer, ABAB block copolymer, ABABA block copolymer, BABAB copolymer, star copolymer containing A and B, monocyclic copolymer containing A and B, containing A and B Examples include a polycyclic copolymer, a cage copolymer containing A and B, and the like.

  (C) The lower limit of the ethylene glycol unit relative to all units in the molecule in the surface modifier (in one embodiment, the water-soluble polymer) is preferably 20%, more preferably 30%, and even more preferably 40% on a mass basis. Preferably, 50% is most preferred. The upper limit of the ethylene glycol unit is not particularly limited, but is preferably 90%, more preferably 80%, and most preferably 70% on a mass basis. With the above range, the solubility in water can be sufficiently satisfied.

(C) The surface modifier can have a graft copolymer structure and / or a block copolymer structure. 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, these copolymers may be partially modified or terminal modified (acid-modified).
In order to ensure good affinity with the (B) cellulose nanofiber, the structure of the (C) surface modifier is desirably the above structure.

  In an exemplary embodiment, (C) the surface modifier may have a cloud point. As the temperature of an aqueous solution of a nonionic surfactant having a polyether chain such as a polyoxyethylene chain as a hydrophilic site is increased, the temperature of a transparent or translucent aqueous solution (this temperature is called a cloud point) ), The phenomenon of cloudiness is observed. That is, when an aqueous solution that is transparent or translucent at a low temperature is heated, the solubility of the nonionic surfactant rapidly decreases at a certain temperature, and the surfactants that have been dissolved until then are aggregated and clouded. And separate from water. It is considered that this is because the nonionic surfactant loses hydration power at high temperatures (the hydrogen bond between the polyether chain and water is broken and the solubility in water is rapidly reduced). The cloud point tends to be lower as the polyether chain is longer. The cloud point is a measure of the hydrophilicity of the nonionic surfactant since it dissolves in water at any temperature at temperatures below the cloud point.

  (C) The cloud point of the surface modifier can be measured by the following method. Using a tuning fork type viscometer (for example, SV-10A manufactured by A & D Corporation), 0.5% by mass, 1.0% by mass, and 5% by mass of the aqueous solution of the surface modifier (C) was used. And measure at a temperature in the range of 0-100 ° C. At this time, a portion showing an inflection point (a change in viscosity or a point at which the aqueous solution is clouded) at each concentration is defined as a cloud point.

  (C) The lower limit of the cloud point of the surface modifier is preferably 10 ° C, more preferably 20 ° C, and most preferably 30 ° C, from the viewpoint of handleability. The upper limit of the cloud point is not particularly limited, but is preferably 120 ° C., more preferably 110 ° C., further preferably 100 ° C., and most preferably 60 ° C. In order to ensure good affinity with (B) cellulose nanofibers having an average fiber diameter of 1000 nm or less, it is desirable that the cloud point of (C) the surface modifier is within the above range.

  (C) The lower limit of the mass ratio of the hydrophilic segment to the hydrophobic segment (hydrophobic segment molecular weight / hydrophilic segment molecular weight) of the surface modifier is not particularly limited, but is preferably 0.01, more preferably 0.01. 0.02, most preferably 0.03. In addition, the upper limit of the mass ratio of the hydrophilic segment to the hydrophobic segment (hydrophobic segment molecular weight / hydrophilic segment molecular weight) is preferably 15, more preferably 10, more preferably 10, from the viewpoint of solubility in water. 5, most preferably 3. In order to ensure good affinity with the cellulose nanofiber (B) having an average fiber diameter of 1000 nm or less, the ratio of the (C) surface modifier is desirably within the above range.

  (C) The lower limit of the number average molecular weight of the surface modifier is 1,000, preferably 2,000, more preferably 3,000, and most preferably 5,000. The upper limit of the number average molecular weight is not particularly limited, but is preferably 1,000,000 or less from the viewpoint of handleability. From the viewpoint of improving the binding or adsorption to (A) the thermoplastic resin and / or (B) the cellulose nanofiber having an average fiber diameter of 1000 nm or less in the resin composition, (C) the number average of the surface modifier. It is desirable that the molecular weight is in the above-mentioned range.

  The lower limit of (C) the amount of the surface modifier is 0.1 part by mass, preferably 0.5 part by mass, more preferably 1 part by mass, based on 100 parts by mass of the thermoplastic resin (A). It is preferably 2 parts by mass, and the upper limit is 200 parts by mass, preferably 50 parts by mass, more preferably 10 parts by mass, and still more preferably 5 parts by mass. By setting the upper limit of (C) the surface modifier as described above, (A) plasticization of the thermoplastic resin can be suppressed, and the strength 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.

  When the amount of the (B) cellulose nanofiber in the resin composition is 100% by mass, the lower limit of the amount of the (C) surface modifier in the resin composition is as good as that of the (B) cellulose nanofiber. From the viewpoint of excellent dispersibility, preferably 0.1% by mass, more preferably 0.5% by mass, more preferably 1.0% by mass, more preferably 1.5% by mass, and still more preferably 1.8% by mass. From the viewpoint of suppressing the plasticization of the thermoplastic resin (A), the upper limit is preferably 100% by mass, more preferably 10% by mass, more preferably 8% by mass, and still more preferably 6% by mass.

  The method of adding the surface modifier (C) when preparing the resin composition is not particularly limited, but (A) a thermoplastic resin, and (B) a cellulose nanoparticle having an average fiber diameter of 1000 nm or less. A method of preliminarily mixing and melting and kneading the fiber and (C) the surface modifier, (A) adding the (C) surface modifier to the thermoplastic resin in advance, preliminarily kneading if necessary, and (B) the average fiber A method in which cellulose nanofibers having a diameter of 1000 nm or less are added and melt-kneaded, (B) cellulose nanofibers having an average fiber diameter of 1000 nm or less and (C) a surface modifier are mixed in advance, and then (A) A method of melt-kneading with a thermoplastic resin, (B) adding a surface modifier (C) to a dispersion in which cellulose nanofibers having an average fiber diameter of 1000 nm or less are dispersed in water, and drying. After a cellulose preparations Te, a method of adding the formulation (A) a thermoplastic resin, and the like are exemplified.

  (C) Specific examples that can be suitably used as a surface modifier include one compound each of which gives a hydrophilic segment (eg, polyethylene glycol) and one compound which gives a hydrophobic segment (eg, diisocyanate, polypropylene glycol, etc.). Copolymers (for example, polyurethanes composed of diisocyanate, polypropylene glycol and polyethylene glycol) obtained by using the above are exemplified. The surface modifier 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, those obtained by modifying the above-mentioned copolymer (for example, those modified with at least one compound selected from unsaturated carboxylic acids, acid anhydrides or derivatives thereof) can also be used.

  Among these, from the viewpoints of heat resistance and mechanical properties, a copolymer containing polyethylene glycol and polypropylene as main components, a polyurethane containing polyethylene glycol and toluene diisocyanate as main components, and polyethylene glycol and 4,4′-diphenylmethane diisocyanate as main components. Polyurethane, a polyurethane whose main component is polyethylene glycol and 4,4'-dicyclohexylmethane diisocyanate, and a mixture thereof are preferable. A copolymer whose main component is polyethylene glycol and polypropylene, and polyethylene glycol, polypropylene glycol and toluene diisocyanate are preferred. Polyurethane as a main component is more preferable from the viewpoint of handleability and cost.

<< (D) aprotic organic solvent >>
Next, the aprotic organic solvent (D) that can be used in the present invention will be described in detail. (D) The aprotic organic solvent has a boiling point of 100 ° C. or higher. A protic organic solvent is an organic solvent having a relatively acidic hydrogen atom bonded to an oxygen atom and serving as a hydrogen bond donor. On the other hand, the aprotic organic solvent is an organic solvent having no highly acidic hydrogen atom. That is, in the present disclosure, the aprotic organic solvent refers to a solvent that is not a hydrogen bond donor. (D) The aprotic organic solvent may be a commercially available reagent or product.

  In a typical embodiment, the lower limit of the molecular weight of (D) the aprotic organic solvent is 50, preferably 100, more preferably 300, and most preferably 1000. The upper limit of the number average molecular weight is not particularly limited, but is preferably 2000 or less from the viewpoint of handleability. From the viewpoint of dissolving the surface modifier (C) and improving the binding or adsorption to (A) the thermoplastic resin and / or (B) the cellulose nanofiber having an average fiber diameter of 1000 nm or less in the resin composition. , Within the above-mentioned range.

  In a typical embodiment, (D) the lower limit of the boiling point of the aprotic organic solvent is 100 ° C, preferably 110 ° C, more preferably 120 ° C, more preferably 150 ° C, Preferably it is 180 ° C. In a preferred embodiment, the upper limit of the boiling point is 300 ° C, more preferably 290 ° C, more preferably 280 ° C, more preferably 260 ° C, and most preferably 240 ° C. (D) The lower limit of the boiling point of the aprotic organic solvent is in the above range, whereby the (C) surface modifier is dissolved, and (B) the cellulose fiber in the resin composition has an average fiber diameter of 1000 nm or less. Tends to be well dispersed. On the other hand, when the upper limit of the boiling point of the aprotic organic solvent (D) is in the above range, plasticization of the resin composition is suppressed, and good strength tends to be maintained.

  In a typical embodiment, (D) the lower limit of the relative dielectric constant at 25 ° C. of the aprotic organic solvent is 1, preferably 2, more preferably 3, and more preferably 5, Most preferably it is 7. The upper limit of the relative permittivity at 25 ° C. is preferably 80, more preferably 70, more preferably 60, and most preferably 50. It is presumed that (D) the relative dielectric constant of the aprotic organic solvent is within the above range, but it is presumed that (C) the surface modifier is dissolved, and the resin composition has (B) an average fiber diameter of 1000 nm or less. This is desirable because (D) the aprotic organic solvent seems to diffuse in certain cellulose nanofibers.

  When producing the resin composition, the lower limit of the amount of the (D) aprotic organic solvent added is preferably 0.1 part by mass, more preferably 100 parts by mass, based on 100 parts by mass of the thermoplastic resin (A). 0.5 parts by mass, more preferably 1 part by mass, still more preferably 2 parts by mass, and the upper limit is preferably 200 parts by mass, more preferably 50 parts by mass, more preferably 10 parts by mass, even more preferably 5 parts by mass. Parts by weight. By setting the upper limit of the addition amount of the (D) aprotic organic solvent to the above, the plasticization of the (A) thermoplastic resin can be suppressed, and the strength can be kept good. In addition, by setting the lower limit of the amount of the (D) aprotic organic solvent to be as described above, the dispersibility of (B) the cellulose nanofiber having an average fiber diameter of 1000 nm or less in the (A) thermoplastic resin is improved. Can be.

  (D) The lower limit of the content of the aprotic organic solvent in the resin composition is 0.1 ppm, preferably 1 ppm, more preferably 10 ppm, and most preferably 15 ppm on a mass basis. The upper limit is 10,000 ppm, preferably 5000 ppm, more preferably 2000 ppm, and most preferably 1000 ppm on a mass basis. From the viewpoint of dispersing the cellulose nanofiber (B) having an average fiber diameter of 1,000 nm or less in the resin composition and further maintaining the strength of the composition, the above range is preferable.

  The amount of the (D) aprotic organic solvent in the resin composition can be easily confirmed by those skilled in the art by a common method. The confirmation method is not limited, but the following method can be exemplified.

  The fragmentation of the resin composition is subjected to pyrolysis GCMS measurement, and (D) the aprotic organic solvent can be determined from the chromatogram and the mass spectrum. The content in the resin composition can be quantified by preparing a calibration curve under the same condition using the (D) aprotic organic solvent detected at this time.

  (D) Specific examples that can be suitably used as the aprotic organic solvent include 1,4-dioxane, anisole, diethylene glycol dimethyl ether, cyclohexanone, N, N-dimethylformamide, N-methylacetamide, N, N-dimethylacetamide , N-methyl-2-pyrrolidone, hexamethylphosphorintriamide, triethyl phosphate, succinonitrile, benzonitrile, pyridine, nitromethane, morpholine, ethylenediamine, dimethylsulfoxide, sulfolane, propylene carbonate and the like.

  In a preferred embodiment, (D) the aprotic organic solvent is water-soluble from the viewpoint of improving the dispersibility of the surface modifier. Preferred examples of the water-soluble (D) aprotic organic solvent include N, N-dimethylformamide.

  Among these, from the viewpoints of heat resistance and availability, diethylene glycol dimethyl ether, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, hexamethyllinsantriamide, dimethyl sulfoxide, sulfolane Are preferred, and N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, hexamethyllinsantriamide, dimethylsulfoxide, and sulfolane are more preferred from the viewpoint of handleability and cost.

<< other components >>
Next, other components that can be used in the present invention will be described in detail. The resin composition of the present embodiment can contain various additives conventionally used for thermoplastic resins and cellulose as long as the purpose of the present embodiment is not impaired. Examples of the additives include, but are not limited to, stabilizers (antioxidants, ultraviolet absorbers, light stabilizers, and heat stabilizers), antistatic agents, flame retardants, and flame retardant auxiliaries. , Impact modifier, fluidity improver, reinforcing material (organic fiber, inorganic filler, fibrous particle, plate-like particle, inorganic pigment), nucleating agent, colorant, lubricant, sliding agent, plasticizer, release agent Examples include a mold agent, a hue improving material, a dispersant, an antibacterial agent, and a preservative. These may be used alone or in combination of two or more. These may be commercially available reagents or products.

  (A) The lower limit of the content of the additive to 100 parts by mass of the thermoplastic resin is not particularly limited, but is preferably 0.001 part by mass, more preferably 0.002 parts by mass, and further preferably 0.003 parts by mass. preferable. The upper limit of the content is not particularly limited, but is preferably 100 parts by mass, more preferably 50 parts by mass, and still more preferably 30 parts by mass.

  The apparatus for producing the resin composition of the present embodiment 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.

  The resin composition of the present invention can be provided in various shapes. Specific examples include resin pellets, sheets, fibers, plates, rods, and the like, and the resin pellets are more preferable in terms of ease of post-processing and transportation. Preferable pellet shapes at this time include a round shape, an elliptical shape, a cylindrical shape, and the like, which differ depending on a cutting method at the time of extrusion. 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 oval, and cuts called strand cuts The pellets cut by the 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.

Specific examples of the method for producing the resin composition include the following methods.
(1) Using a single-screw or twin-screw extruder, melt a mixture of (A) a thermoplastic resin and (B) cellulose nanofiber, (C) a surface modifier, and (D) an aprotic organic solvent. A method in which the mixture is kneaded, extruded into a strand, cooled and solidified in a water bath to obtain a pellet-shaped molded body.
(2) Using a single-screw or twin-screw extruder, melt a mixture of (A) thermoplastic resin, (B) cellulose nanofiber, (C) surface modifier, and (D) aprotic organic solvent. A method in which the mixture is kneaded, extruded into a rod shape or a cylindrical shape, and cooled to obtain an extruded product.
(3) Using a single-screw or twin-screw extruder, melt a mixture of (A) a thermoplastic resin, (B) cellulose nanofiber, (C) a surface modifier, and (D) an aprotic organic solvent. A method of kneading and obtaining an extruded sheet or film-like molded body from a T-die.

Further, as a specific example of a method of melt-kneading a mixture of (A) a thermoplastic resin, (B) cellulose nanofiber, (C) a surface modifier, and (D) an aprotic organic solvent, the following method is used. No.
(1) Melt kneading (A) thermoplastic resin and (B) cellulose nanofiber, (C) surface modifier, (D) aprotic organic solvent, and water mixed in a desired ratio at a time. how to.
(2) (A) a thermoplastic resin and, if necessary, (C) a surface modifier and / or (D) an aprotic organic solvent, after melt-kneading, (B) cellulose nanofiber mixed at a desired ratio; A method in which water and, if necessary, (C) a surface modifier and / or (D) an aprotic organic solvent are added, followed by melt-kneading.
(3) After melt-kneading (A) a thermoplastic resin, (B) cellulose nanofiber mixed in a desired ratio, (C) a powder mixed with a surface modifier, (D) an aprotic organic solvent, and water. (B) Cellulose nanofibers and water mixed in a desired ratio, and if necessary, (C) a surface modifier and / or (D) an aprotic organic solvent, and further melt kneading all at once. Method.
(4) (A) thermoplastic resin, (B) cellulose nanofiber, (C) surface A method in which a modifier, water, and (D) an aprotic organic solvent are added, and the mixture is further melt-kneaded.
(5) A method in which the above (1) to (4) are dividedly added at Top and Side at an arbitrary ratio using a single-screw or twin-screw extruder and melt-kneaded.

<< member >>
The present embodiment also provides a molded article formed from the above-described resin composition. The molded body can be in the form of the following members. The method for molding the resin composition is not particularly limited, and a known molding method can be applied. For example, extrusion molding, injection molding, vacuum molding, blow molding, injection compression molding, decorative molding, other material molding, gas assist injection molding, foam injection molding, low pressure molding, ultra thin injection molding (ultra high speed injection molding), It can be molded by any of molding methods such as in-mold composite molding (insert molding, outsert molding).

  As the use of the member of the present embodiment obtained from the above-mentioned cellulose-containing resin composition, sliding resistance, excellent discoloration characteristics, small dimensional change due to heat after molding, and applications requiring these characteristics are preferable. It is.

  The application of the member of the present embodiment is not limited to the following, but includes, for example, an application of a general thermoplastic resin composition. Specific examples of such applications include, but are not limited to, cams, sliders, levers, arms, clutches, felt clutches, idler gears, pulleys, rollers, rollers, key stems, key tops, and shutters. , Reels, shafts, joints, shafts, bearings, guides, and other mechanical parts; outsert molded resin parts, insert molded resin parts, chassis, trays, side plates, printers, and offices represented by copiers Parts for automation equipment; Video tape recorder (VTR), video movie, digital video camera, camera, and parts for camera or video equipment represented by digital camera; Cassette player, DAT, LD (Laser disk), MD (Mini disk) , D (Compact disk) [including CD-ROM (Read only memory), CD-R (Recordable), CD-RW (Rewritable)], DVD (Digital versatile disk) [DVD-ROM, DVD-R, DVD + R, DVD -RW, DVD + RW, DVD-R DL, DVD + R DL, DVD-RAM (Random access memory), DVD-Audio), Blu-ray (registered trademark) Disc, HD-DVD, and other optical disk drives; MFD ( Multi-function display (MO), MO (Magneto-Optical Disk), navigation system and music, video or Parts for communication equipment typified by information equipment, mobile phones, and facsimile machines; parts for electric equipment; parts for electronic equipment, etc. The molded article of the present embodiment is used as a part for automobiles as a gasoline tank or fuel. Parts around fuel such as pump modules, valves, gasoline tank flanges, etc .; Parts around doors such as door locks, door handles, window regulators, speaker grills, etc .; representatives such as slip rings for seat belts, press buttons, etc. Peripheral seat belt parts; Combination switch parts, switches, clips, etc .; mechanical parts for inserting and removing the pencil tip of the mechanical pencil; core for the mechanical pencil; wash basins, drain outlets, and drain cock opening and closing mechanism parts; Locking mechanism for opening / closing part of vending machine, parts discharging mechanism parts; cords for clothing Upper, adjuster, button; watering nozzle, watering hose connection joint; stair railing, and architectural supplies that support flooring; disposable cameras, toys, fasteners, chains, conveyors, buckles, sports equipment, vending machines , Furniture, musical instruments, industrial machinery parts (for example, electromagnetic equipment housings, roll materials, transfer arms, medical equipment parts, etc.), general mechanical parts, parts for automobiles, railways and vehicles (for example, outer panels, chassis, aerodynamic parts) , Seats, friction materials inside the transmission, etc.), marine components (eg, hulls, seats, etc.), aviation-related parts (eg, fuselage, wings, tail wings, rotor blades, fairings, cowls, doors, seats, interior materials, etc.), Spacecraft, satellite components (motor case, wings, structures, antennas, etc.), electronic and electrical components (for example, personal computer housings, mobile phones) Telephone housings, OA equipment, AV equipment, telephones, facsimile machines, home appliances, toy goods, etc., architectural / civil engineering materials (for example, reinforcing steel substitute materials, truss structures, suspension bridge cables, etc.), daily necessities, sports and leisure goods (Eg, golf club shafts, fishing rods, tennis and badminton rackets, etc.), housing members for wind power generation, etc., and containers / packaging members, for example, high-pressure containers filled with hydrogen gas used in fuel cells, etc. Material for

  When the member of the present embodiment is a resin composite film, it is suitable for reinforcing a laminated board in a printed wiring board. Others, for example, insulation cylinders, insulation levers, arc extinguishing plates, operation rods, insulation spacers in generators, transformers, rectifiers, circuit breakers, and controllers, insulation spacers, cases, wind tunnels, end bells, wind seals, switch boxes in standard electrical products , Cases, crossbars, insulating shafts, fan blades, mechanical parts, transparent resin substrates, speaker diaphragms, eta diaphragms, TV screens, fluorescent light covers, antennas for communication equipment and aerospace, horn covers, radomes, cases, Mechanical components, wiring boards, aircraft, rockets, satellite electronics components, railway components, marine components, bathtubs, septic tanks, corrosion-resistant equipment, chairs, safety caps, pipes, tank lorries, cooling towers, floating breakwaters, underground It can be suitably used as an industrial part typified by a buried tank or container housing equipment.

<< Binding / Adsorption >>
In the resin composition of the present embodiment, (C) the surface modifier binds to (A) a thermoplastic resin and / or (B) cellulose nanofiber (for example, a chemical bond such as an ionic bond or a covalent bond) or adsorbs ( For example, chemical adsorption or physical adsorption can be performed. A typical example of physisorption is a van der Waals force in which an adsorbate ((C) surface modifier) acts between a solid adsorbent ((A) thermoplastic resin and / or (B) cellulose nanofiber). It is a phenomenon that the solid adsorbent is concentrated on the surface. In general, the Van der Waals force is a much weaker interaction than a chemical bond (ionic bond, covalent bond, etc.), so that a physically adsorbed molecule is easily desorbed by a physical operation such as heating and decompression.

  The physical adsorption phenomenon can be easily confirmed by those skilled in the art by a general method. The confirmation method is not limited, but the following method can be exemplified.

  First, a surface analysis of a molded article composed of the resin composition is performed. Confirm the components of (A) thermoplastic resin or (B) cellulose nanofibers near the molded body by infrared spectroscopy, time-of-flight secondary ion mass spectrometry, local pyrolysis GC-MS, etc. Can be done.

  Next, the following operation is performed. In the resin composition, (A) a thermoplastic resin, (C) a surface modifier, and (D) an aprotic organic solvent are dissolved. The solution is separated from (B) the cellulose nanofiber, and the cellulose nanofiber is isolated. After reprecipitating the solution (that is, the solution in which (A) the thermoplastic resin is dissolved), and taking out (A) the thermoplastic resin, (C) the surface modifier, and (D) the aprotic organic solvent, The solution is allowed to dry. The two dried components are subjected to component analysis by various methods, and if the components match the components detected by the surface analysis, it can be confirmed that the components are components related to physical adsorption.

  On the other hand, a chemical bond is an irreversible bond depending on physical operations, unlike physical adsorption. When (C) the surface modifier is chemically bonded to (A) the thermoplastic resin and / or (B) the cellulose nanofiber, thermal decomposition and hydrolysis of (A) the thermoplastic resin and (B) the cellulose nanofiber are performed. (C) The surface modifier can be easily decomposed by alkali decomposition or the like.

  The chemical bonding phenomenon can be easily confirmed by those skilled in the art by a general method. The confirmation method is not limited, but the following method can be exemplified.

First, (A) the thermoplastic resin and (B) the cellulose nanofiber of the resin composition are isolated. First, (A) a thermoplastic resin and (D) an aprotic organic solvent of a resin composition are dissolved. The solution and (B) the cellulose nanofibers are separated to isolate the cellulose component. The solution (that is, the solution in which (A) the thermoplastic resin is dissolved) is reprecipitated, and the (A) thermoplastic resin and (D) the aprotic organic solvent are taken out, and the solution is dried. By directly analyzing the isolated (A) thermoplastic resin and (B) cellulose nanofiber by ¹ H-NMR or ¹³ C-NMR, the components that are chemically bonded can be confirmed.

Next, the following operation is performed. The isolated (A) thermoplastic resin and (B) cellulose nanofiber are subjected to thermal decomposition, hydrolysis, alkali decomposition, etc., and the decomposed components are analyzed by infrared spectroscopy, GC-MS, LC-MS. The structure of the component before decomposition is determined by analyzing it by time-of-flight secondary ion mass spectrometry, ¹ H-NMR, ¹³ C-NMR and the like. If the components detected before and after decomposition match, it can be confirmed that the component is a component related to chemical bonding.

<< Linear expansion coefficient >>
Since the resin composition of this embodiment contains (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 molded product. Specifically, the linear expansion coefficient of the resin molded product in the temperature range of 0 ° C to 60 ° C is preferably 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.

<< Vibration fatigue characteristics >>
Since the resin composition of the present embodiment contains (B) cellulose nanofibers and (C) a specific surface modifier, and further contains (D) an aprotic organic solvent, the resin composition is superior to a conventional molded article. Vibration fatigue characteristics can be exhibited. Although the cause of such excellent vibration fatigue properties has not been elucidated, (B) an aprotic organic solvent is added to the interface where (B) cellulose nanofiber and (C) a specific surface modifier are in close contact. Is presumed to have permeated and improved the interface adhesion.

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 (number average molecular weight 18000) manufactured by Ube Industries, Ltd.
(A-2) PP Prime Polymer Co., Ltd. Prime Polypro J105G (number average molecular weight 5000 or more)
(A-3) POM manufactured by Asahi Kasei Corporation Tenac TM 4520 (number average molecular weight 70000)

<< (B) cellulose nanofiber >>
(B-1) Cellulose A
After cutting the linter pulp, the purified pulp from which the hemicellulose portion has been removed is heated in a hot water of 120 ° C. or more for 3 hours using an autoclave, and the solid content becomes 1.5% by mass 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 defibrating function (hereinafter, referred to as a defibrating blade) is processed for 2.5 hours with a defibrating blade having a high cutting function (hereinafter, referred to as a "cutting blade"). The mixture was further beaten for 2 hours to obtain cellulose A.
(B-2) Cellulose B
[0108] Cellulose B was prepared by the method described in Example 1 of WO 2017/159823.

<Degree of polymerization of cellulose component>
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).
<Crystal form and crystallinity of cellulose component>
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.

<L / D of cellulose component>
The cellulose component was made into a pure water suspension at a concentration of 1% by mass, and a high shear homogenizer (trade name “Excel Auto Homogenizer ED-7” manufactured by Nippon Seiki Co., Ltd., processing condition: rotation speed 15,000 rpm × 5 minutes) The aqueous dispersion dispersed in the above step was diluted with pure water to 0.1 to 0.5% by mass, cast on mica, and air-dried to obtain a product as measured by an atomic force microscope (AFM). The ratio (L / D) between the major axis (L) and the minor axis (D) of the obtained particle image was determined and calculated as an average value of 100 to 150 particles.

<Average diameter of cellulose component>
In a planetary mixer (trade name “5DM-03-R”, manufactured by Shinagawa Kogyo KK, trade name “5DM-03-R”, stirring blade is a hook type), the cellulose component is set to 40% by mass as solid content at 126 rpm for 30 minutes at room temperature and normal pressure. Kneaded. 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 integrated 50% particle diameter (volume average particle diameter) in the frequency particle size distribution was measured, and this value was defined as the average diameter.

<< (C) surface modifier >>
(C-1) 66 parts by mass of polyethylene oxide (Mn3700), 33 parts by mass of polypropylene oxide (Mn2000), and 0.6 parts by mass of KOH as a catalyst were reacted at 160 ° C. for 4 hours to obtain c-1 (Mn9400 ABA block copolymer). Was obtained.
(C-2) 66 parts by mass of polyethylene oxide (Mn550), 33 parts by mass of polypropylene oxide (Mn2000), and 0.6 part by mass of KOH as a catalyst were reacted at 160 ° C. for 4 hours, and c-1 (Mn3100 ABA type block copolymer) was reacted. Was obtained.
(C-3) Polyethylene oxide (Mn20000) was used.
(C-4) Superflex (registered trademark) 300 manufactured by Daiichi Kogyo Co., Ltd. was used.
The molecular weight could not be measured due to the aqueous dispersion emulsion.

<(C) Measurement of molecular weight of surface modifier>
Each surface modifier was measured under the following conditions.
[GPC measurement]
Those which were solid at room temperature were heated above the melting point and melted, then dissolved in water and measured.
Apparatus name: HLC-8320GPC EcoSEC (manufactured by Tosoh Corporation)
Column: Shodex GPC KD-802 + KD-80 (manufactured by Showa Denko KK)
Eluent: 0.01 M LiBr in DMF
Flow rate: 1.0 mL / min
Detector: RI
Measurement temperature: 50 ° C

<(C) Cloud point of surface modifier>
Those which were solid at room temperature were heated to above the melting point and melted, then dissolved in water to obtain samples.
Apparatus name: SV-10A manufactured by A & D Corporation
Measurement concentration: 0.5% by mass, 1.0% by mass, 5% by mass
Measurement temperature: 0 to 90 ° C
Those which did not show a cloud point in the above method were sealed in a glass-made visible container. Thereafter, the temperature was increased, and the clouding point of the aqueous precipitation solution was visually confirmed to measure the clouding point. Table 2 shows the measurement results.

<< (D) aprotic organic solvent >>
The solvents described in Table 3 were used. As the relative permittivity, the numbers described in the Chemical Chemistry Handbook, Basic Edition, edited by the Chemical Society of Japan, Ip770-777, were used.

<< Production conditions >>
Using a twin-screw extruder (TEM-26SS extruder manufactured by Toshiba Machine Co., Ltd. (L / D = 48, with vacuum vent)), polyamide-based material is 260 ° C, polypropylene-based material is 190 ° C, polyoxymethylene The material is set at a cylinder temperature of 200 ° C., (A), components are supplied from a quantitative feeder from the main throat section of the extruder, (B) an aqueous dispersion of cellulose nanofiber, (C) a surface modifier, and (D) The aprotic organic solvent was previously batch-mixed, supplied from the side of the extruder through a quantitative feeder, and extruded into a strand at a rate of 15 kg / hour and a screw rotation speed of 250 rpm. The top collecting hopper of the extruder was used as a B1 barrel, and from there, a vacuum was maintained at a 10-barrel section to reduce the pressure. Quenched Te, cut with a strand cutter to obtain a resin composition pellet.

<< Measurement of molding conditions and mechanical properties >>
A multipurpose test piece based on ISO294-3 was molded using an injection molding machine.
Polyamide-based material: Conditions based on JIS K6920-2 Polypropylene-based material: Conditions based on JIS K6921-2 Polyoxymethylene-based material: Conditions based on JIS K7364-2 Raw material resin (that is, thermoplastic resin alone) and resin composition For each of the products (that is, the cellulose-containing resin composition), the tensile yield strength was measured in accordance with ISO527, and the flexural modulus was measured in accordance with ISO179.
In addition, since the polyamide-based material changes due to moisture absorption, it was stored in an aluminum moisture-proof bag immediately after molding to suppress moisture absorption.

<< Linear expansion coefficient >>
From the center of the multipurpose test piece, a cubic sample of 4 mm long, 4 mm wide, and 4 mm long is cut out with a precision cut-saw, and measured in a measurement temperature range of -10 to 80 ° C in accordance with ISO11359-2. The expansion coefficient between 60 ° C was calculated.

<< Abrasion resistance >>
Regarding the multipurpose test piece obtained in the above << Molding condition / mechanical property measurement >>, a reciprocating friction and wear tester (AFT-15MS type manufactured by Toyo Seimitsu Co., Ltd.) was used. As a mating material, a SUS304 test piece (sphere having a diameter of 5 mm) was used. ), A sliding test was performed at a linear velocity of 50 mm / sec, a reciprocating distance of 50 mm, a load of 9.8 N, a number of reciprocating cycles of 10,000, a temperature of 23 ° C., and a humidity of 50%. The amount of abrasion was measured using a confocal microscope (OPTELICS (registered trademark) H1200, manufactured by Lasertec Corporation). The wear depth was an average of the values measured at n = 4. The measurement was performed at an equal interval of 12.5 mm from the end of the wear mark. The lower the wear depth, the better the wear characteristics.

<< cantilever bending fatigue properties >>
From the pellets of the obtained resin composition, using an EC-75NII molding machine manufactured by Toshiba Machine Co., Ltd., a resin molded body of a test piece (thickness 6 mm, type III test piece) conforming to ISO294-3 was obtained. Using this test piece, measurement of a cantilever bending fatigue test was performed under an environment based on JIS-K7119 under a repetition rate of 35 Hz, a temperature of 23 ± 1 ° C., and a humidity RH of 60 ± 5%. The number of times from the intersection of the stress-life curve obtained at this time and the stress of 30 MPa to breakage was calculated.

[Examples 1 to 18 and Comparative Examples 1 to 9]
A resin composition was obtained using (A) a thermoplastic resin, (B) a cellulose nanofiber, (C) a surface modifier, and (D) an aprotic organic solvent in the proportions shown in Tables 4 to 8, respectively. The obtained composition was evaluated according to the evaluation method described above.

  As described above, linear expansion is achieved by blending (A) a thermoplastic resin, (B) cellulose nanofiber, (C) a surface modifier, and (D) an aprotic organic solvent in appropriate types and amounts. It can be seen that mechanical properties can be significantly improved while maintaining the coefficient, wear resistance, and vibration fatigue characteristics.

  Since the resin composition according to the present invention has excellent vibration fatigue properties and sliding resistance, and has a small dimensional change due to heat after molding, various applications requiring these properties are suitably applied. You.

Claims (10)

  (A) 100 parts by mass of a thermoplastic resin, (B) 1 to 200 parts by mass of cellulose nanofiber having an average fiber diameter of 1000 nm or less, (C) 0.1 to 200 parts by mass of a surface modifier, and ( D) A resin composition containing 0.1 to 10000 ppm by mass of an aprotic organic solvent having a boiling point of 100 ° C or higher.   (A) The group consisting of a polyolefin resin, a polyamide resin, a polyester resin, a polyacetal resin, a polyacrylic resin, a polyphenylene ether resin, a polyphenylene sulfide resin, and a mixture of any two or more of these resins. The resin composition according to claim 1, which is selected from the group consisting of:   The resin composition according to claim 1, wherein (D) the aprotic organic solvent is water-soluble.   (D) The resin composition according to any one of claims 1 to 3, wherein the aprotic organic solvent has a relative dielectric constant at 25 ° C of 3 to 80.   (D) The resin composition according to any one of claims 1 to 4, wherein the aprotic organic solvent has a boiling point of 110 to 290 ° C.   (C) The resin composition according to any one of claims 1 to 5, wherein the surface modifier contains a hydrophilic segment and a hydrophobic segment in a molecule.   The resin composition according to any one of claims 1 to 6, comprising (C) a surface modifier in an amount of 1 to 100% by mass based on (B) the cellulose nanofiber.   (C) The resin composition according to any one of claims 1 to 7, wherein the surface modifier has a cloud point of 20 ° C or higher.   (C) The resin composition according to any one of claims 1 to 8, wherein an ethylene glycol unit in a molecule of the surface modifier is 50% by mass or more of all units.   A molded article formed from the resin composition according to claim 1.