JP6684371B2 - Kneading composition, method for producing the same, and composite - Google Patents

Description

  The present invention relates to a kneading composition having a high content of cellulose nanofibers dispersed (or uniformly dispersed) in a thermoplastic resin, a method for producing the same, and a composite (or a composite material) containing the kneading composition and a resin. .

  Cellulose, which is a fiber of plant origin, has a small environmental load, is a sustainable resource, and has excellent properties such as high elastic modulus, high strength, and low linear expansion coefficient. In particular, micronized cellulose nanofibers (cellulose nanofibers) are useful as a reinforcing agent for resins, and resin compositions (composite materials) in which cellulose nanofibers are dispersed in resins are known.

  JP-A-2014-234472 (Patent Document 1) describes a microporous stretched film in which cellulose nanofibers are uniformly dispersed. As a method for producing this film, cellulose obtained by half-esterifying hydroxyl groups of cellulose having a powder particle size with a dibasic acid anhydride (succinic anhydride) is dispersed in a plasticizer (paraffin), and the obtained cellulose powder dispersion mixture is used as a polyolefin. (Polyethylene) is melt-kneaded, the resulting polyolefin resin composition is stretched to form a microporous stretched film, and a plasticizer is extracted from this film. In the examples of this document, the ratio (weight ratio) of polyethylene to paraffin (plasticizer) is the former: the latter = 30: 70, and the ratio of cellulose nanofibers in the composition is 0.5% by weight. Is listed. However, the resin is limited to polyolefin and the cellulose is also limited to modified cellulose. Moreover, since the semi-esterified cellulose is uniformly dispersed in the plasticizer, it is difficult to prepare a resin composition (kneading composition) containing a high content of cellulose nanofibers. Further, it is necessary to remove the plasticizer by extraction after forming the film, so that not only the shape of the molded body is limited, but also the productivity of the molded product is low.

  A resin composition (masterbatch) in which a high content of cellulose nanofibers is dispersed in a resin is also known, and a composite material in which the masterbatch is mixed (or kneaded) with a resin is also disclosed.

  Japanese Unexamined Patent Publication No. 2013-14741 (Patent Document 2) discloses a cellulose nanofiber in which a natural cellulose fiber is reacted with an N-oxyl compound (oxidizing agent) to oxidize a part of the methylol group at the C6 position into a carboxyl group. And / or a resin-modifying additive (masterbatch) containing the cellulose nanofiber derivative and resin particles. In the examples of this document, TEMPO (2,2,6,6-tetramethyl-1-piperidine-N-oxyl), sodium hypochlorite and sodium bromide were used to prepare pulp fibers in the presence of deionized water. Oxidation treatment is carried out, and the obtained oxidized pulp fiber is subjected to a micronization treatment with a mixer in ion-exchanged water to obtain a dispersion liquid of cellulose nanofibers. Further, this cellulose nanofiber dispersion is mixed with a separately prepared water emulsion having a resin particle concentration of 25% by weight, such as polyethylene, and then stirred and dried by mist-drying to modify the resin having a content of cellulose nanofibers of 50% by mass. Obtaining additive (masterbatch). Further, in this document, the oxidation treatment weakens the hydrogen bond between the surfaces, which is the driving force of the strong cohesive force between the microfibrils, and easily achieves a fine fiber diameter. It is described that the repulsive force increases the dispersion stability of the nanofibers. However, in the oxidation treatment step, the degree of polymerization may be lowered (or the molecular chain of cellulose may be cut), and the mechanical strength of cellulose may be lowered. Moreover, a part of the aldehyde group may remain without being oxidized, and the aldehyde group may cause coloration by heating. Moreover, since the cellulose and the resin are mixed in the form of an aqueous dispersion, applicable resins are limited. Furthermore, in addition to the oxidation treatment step and the dispersion liquid preparation step, a step of removing a large amount of water in the dispersion liquid by spray drying is required, and the resin composition cannot be simply prepared.

  In addition, "Molding processing '14", published by Japan Society for Plastic Molding Processing, pages 377 to 378 (Non-Patent Document 1), cellulose, fluorene compound [bisphenoxyethanol fluorene (BPEF), bisphenol fluor, under argon atmosphere. Orange glycidyl ether (BPFG)], an aprotic polar solvent, and a catalyst were reacted to remove unreacted fluorene and the catalyst to obtain modified cellulose. A 2% dioxane dispersion of this modified cellulose was used as polylactic acid dioxane. After mixing with the solution, atomizing with a homogenizer and precipitating with methanol, a composite (masterbatch) of 30% by weight of cellulose nanofibers and polylactic acid was obtained, and further, the obtained masterbatch and polylactic acid were combined. Melt-kneaded with 10 wt% cellulose nanofiber It is described that was prepared polylactic acid composite containing. This document describes the appearance of a sheet (film) formed of the polylactic acid composite, but the sheet (film) is slightly cloudy in appearance in spite of the content of cellulose of 10% by weight. is doing. Therefore, there is a possibility that cellulose fibers having a microfiber diameter are mixed. Further, it is necessary to prepare in advance modified cellulose to which a fluorene compound is bound (or modified) in the presence of a catalyst. Furthermore, since a large amount of organic solvent is required, productivity is reduced.

  Note that in JP-A-2014-162880 (Patent Document 3), a step of mixing cellulose, a resin, and a dispersant having a resin affinity segment A and a cellulose affinity segment B to obtain a resin composite composition A method for producing a resin composite composition containing is described. In addition, in the experimental section of the example of this document, pulp was nanofiberized by low-temperature kneading of pulp, polyethylene (PE), a dispersant, and water (fiber ratio 9%), and the obtained fiber ratio 10%. It is described that the resin composition was obtained by melt-kneading the composition of 1) with a resin. However, it is described that a large amount of pulp remained and nano-defibration was insufficient.

JP-A-2014-234472 (Claims, Examples, [0007]) JP, 2013-14741, A (claim, example, [0014] [0017] [0024]) Japanese Patent Laid-Open No. 2014-162880 (claims, examples)

"Molding processing '14", published by Japan Society for Plastic Molding Processing, pages 377-378.

  Therefore, an object of the present invention is to provide a kneading composition in which cellulose fibers are dispersed in a resin in a nanometer size (evenly dispersed) even with a high content, and a production method capable of preparing such a kneading composition simply and easily. Another object is to provide a composite (or composite material) containing the kneading composition and a resin.

  Another object of the present invention is to provide a kneading composition having a wide application range of a resin and having cellulose nanofibers dispersed (uniformly dispersed) in the resin, a method for producing the same, and a composite containing the kneading composition and the resin. It is in.

  Still another object of the present invention is to provide a kneading composition in which cellulose nanofibers are dispersed in a resin without oxidizing the cellulose (or cellulose nanofibers), a method for producing the same, and a composite containing the kneading composition and the resin. To provide the body.

  Another object of the present invention is to prepare a kneading composition in which cellulose nanofibers are dispersed in a resin, a method for producing the same, and a composite containing the kneading composition and a resin, without preparing a cellulose nanofiber having a modifier bonded thereto in advance. To provide the body.

  As a result of intensive studies to achieve the above-mentioned object, the present inventors have surprisingly found that when cellulose (cellulose raw material) is kneaded in the presence of a resin solution while heating to remove the solvent, cellulose is microfibrillated. The present invention has been completed by discovering that cellulose nanofibers having a high content can be uniformly dispersed in a resin.

  That is, the kneading composition of the present invention is a kneading composition in which cellulose nanofibers are dispersed in a solvent-soluble thermoplastic resin, wherein the ratio of the cellulose nanofibers is relative to the total amount of the resin and the cellulose nanofibers. 20 wt% or more (for example, 40 wt% or more). In the present invention, even if a high content of cellulose nanofibers is contained, aggregation of the cellulose nanofibers can be suppressed, and the cellulose nanofibers are usually uniformly dispersed in the thermoplastic resin matrix.

  The solvent may be at least one selected from hydrocarbons, halogenated hydrocarbons, alcohols, ethers, ketones, and esters. Further, the thermoplastic resin may be at least one selected from a styrene resin, a modified olefin resin, an acrylic resin, a halogen-containing resin, and a polyester resin. Further, the thermoplastic resin may be a condensation type thermoplastic resin.

  The cellulose nanofiber may be a modified cellulose nanofiber to which a compound having a 9,9-bis (aryl) fluorene skeleton is bound. The ratio of the compound having a 9,9-bis (aryl) fluorene skeleton bonded to the cellulose nanofiber may be about 0.1 to 20% by weight based on the total amount of the modified cellulose nanofiber. Further, in the present invention, the thermoplastic resin can be dispersed in a finely divided form without modifying or oxidizing the cellulose fiber. Therefore, the cellulose nanofibers may be unmodified cellulose nanofibers to which no modifier is bound, or may be unoxidized cellulose nanofibers.

  The kneaded composition may not substantially contain cellulose fibers having a fiber diameter of micrometer, and the cellulose nanofibers may have an average fiber diameter of about 5 to 500 nm. The average fiber length of the cellulose nanofibers may be 10 μm or more. Further, the content of the cellulose nanofibers may be about 40 to 60% by weight based on the total amount of the resin and the cellulose nanofibers.

  The kneading composition of the present invention may be used as a reinforcing agent for resins. Therefore, the present invention also includes a complex containing the kneading composition and the resin.

  In the method of the present invention, a composition containing at least a resin solution in which a thermoplastic resin is dissolved in the solvent and cellulose (or a cellulose raw material) is kneaded while removing the solvent to produce the kneaded composition. In the present invention, a solution-like resin and cellulose (or a resin, a solvent and cellulose) are kneaded to disperse the cellulose (or a cellulose raw material) in the resin solution in the initial kneading, and then the solvent is removed. In the process of increasing the viscosity of the system, the shearing force can be effectively applied. Probably the microfibrillation (or nanoization) of cellulose (cellulose raw material) can be promoted, and even if the content is high, cellulose nano Agglomeration of fibers can be suppressed, and a kneaded composition in which the fibers are uniformly dispersed can be obtained.

  In this method, the composition may be kneaded while being heated from a temperature equal to or lower than the boiling point of the solvent to remove the solvent, and the composition may be kneaded while melting the thermoplastic resin. That is, the kneading can be carried out while the temperature is raised from the boiling point of the solvent to at least the temperature at which the thermoplastic resin can be melted. In the composition to be kneaded, the composition containing the resin solution and cellulose may be kneaded in the presence of a compound having a 9,9-bis (aryl) fluorene skeleton without adding a catalyst.

  In the present invention, probably because the thermoplastic resin penetrates and intervenes between the finely divided cellulose nanofibers, the cellulose nanofibers are uniformly dispersed in the resin in the kneading composition even if the content is high. Moreover, since a resin that is soluble in a solvent can be used, the range of application of the resin can be expanded. Further, the kneading composition can be simply and easily obtained by a simple operation of kneading. Moreover, when kneading is performed in the presence of a modifier (for example, a compound having a 9,9-bis (aryl) fluorene skeleton), the modifier and cellulose (or cellulose nanofibers) are likely to react with each other. It is possible to form a kneading composition containing modified cellulose nanofibers to which a modifier is bound without preparing modified cellulose to which the modifier is bound in advance, and moreover, because hydrogen bonds acting between fibers can be relaxed. The diameter can be reduced. Further, by using this method, since it is possible to disperse without performing the oxidation treatment of the cellulose, it is possible to suppress the decrease in the degree of polymerization of cellulose due to the oxidation treatment, and because there is no fear that the cellulose nanofibers form an aldehyde group, Coloring can also be prevented. Such a kneaded composition having a large content of cellulose nanofibers can be used as a masterbatch (or a resin reinforcing agent) and can be applied to various resins, so that a composite (resin strength, etc.) with improved resin properties ( Composite materials) can be formed. In particular, the composite including the modified cellulose nanofibers can effectively improve the strength and linear expansion characteristics, probably because the composite has high dispersibility in the resin.

FIG. 1 is a scanning electron microscope (SEM) photograph of masterbatch 1 obtained in Example 1. FIG. 2 is a diagram showing Fourier transform infrared spectroscopy (FT-IR) spectra of the master batch and pulp raw material obtained in Examples 1 and 2 and Reference Example 1. FIG. 3 is a scanning electron microscope (SEM) photograph of the masterbatch 2 obtained in Example 2. FIG. 4 is a polarization micrograph of masterbatch 3 obtained in Comparative Example 1. FIG. 5 is a polarization micrograph of pulp raw material. FIG. 6 is a polarization micrograph of masterbatch 4 obtained in Comparative Example 2. FIG. 7 is a polarization micrograph of masterbatch 5 obtained in Reference Example 1. FIG. 8 is a scanning electron microscope (SEM) photograph of masterbatch 5 obtained in Reference Example 1.

  The kneading composition of the present invention is a kneading (or melt kneading) composition in which cellulose nanofibers are dispersed (uniformly dispersed) in a solvent-soluble thermoplastic resin.

[Thermoplastic resin]
The thermoplastic resin constituting the kneaded composition may be any resin that is soluble in a solvent, and the solvent can be selected according to the type of the resin, such as water, an organic solvent [for example, hydrocarbons (hexane, octane, Aliphatic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as toluene and xylene), halogenated hydrocarbons (dichloromethane, chloroform, carbon tetrachloride, dichloroethane, trichloroethylene, etc.), alcohols (methanol, ethanol, propanol, C _1-4 alkanols such as isopropanol), ethers (dialkyl ethers such as diethyl ether and diisopropyl ether, cyclic ethers such as dioxane and tetrahydrofuran), ketones (dialkyl ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone). Tons, cycloalkane ketones such as cyclohexanone), esters (acetic acid esters such as methyl acetate, ethyl acetate, butyl acetate), amides (dimethylformamide, diethylformamide, dimethylacetamide, diethylacetamide, etc.), sulfoxides (dimethylformamide) Sulfoxide, etc.), Nitriles (acetonitrile, benzonitrile, etc.), Cellosolves (methyl cellosolve, ethyl cellosolve), Carbitols (ethyl carbitol, etc.), Cellosolve acetates, carbitol acetates, Carbonates (dimethyl carbonate, ethylene) Carbonate, propylene carbonate, etc.)]. These solvents may be used alone or in combination of two or more.

  Of these solvents, those with relatively low boiling points, such as hydrocarbons (hexane, cyclohexane, toluene, etc.), halogenated hydrocarbons (dichloromethane, chloroform, carbon tetrachloride, etc.), alcohols (methanol, ethanol, etc.) ), Ethers (diethyl ether, dioxane, tetrahydrofuran, etc.), ketones (acetone, methyl ethyl ketone, etc.), esters (methyl acetate, ethyl acetate, etc.) and the like are preferable. The boiling point of the solvent may be, for example, 40 to 150 ° C, preferably 50 to 110 ° C, and more preferably 60 to 105 ° C. When such a solvent having a low boiling point is used, the viscosity of the resin increases as the solvent evaporates (or evaporates), so that the nano force (or micronization) of cellulose can be promoted by applying a shearing force. From the viewpoint of the dispersibility of cellulose, polar solvents such as alcohols, ethers, ketones, and esters are more preferable, and ethers are preferable from the viewpoint of suppressing hydrolysis and increasing the permeability to fibers. Particularly preferred are the compounds, ketones and esters.

  Such a solvent-soluble thermoplastic resin may be a water-soluble resin or a water-insoluble resin.

  As the water-soluble resin, for example, vinyl alcohol-based resin [polyvinyl alcohol (polyvinyl alcohol having a saponification degree of 60 to 100% or the like), polyalkylene glycol-based resin (polyethylene glycol, polyethylene glycol-polypropylene glycol block copolymer, etc.) , Vinylpyrrolidone-based resins (polyvinylpyrrolidone, etc.) and the like.

  As the water-insoluble resin, an addition polymerization type thermoplastic resin (for example, a styrene resin, an olefin resin, a modified olefin resin, an acrylic resin, a halogen-containing resin, a vinyl ester resin or a derivative thereof, a thermoplastic polyurethane resin) Etc.), condensed thermoplastic resins (for example, polyester resins, polyamide resins, polyether resins, polycarbonate resins, polysulfone resins, thermoplastic polyimide resins, thermoplastic polyurethane resins, etc.) and the like.

  Examples of the styrene resin include homopolymers or copolymers of styrene monomers (styrene, α-methylstyrene, vinyltoluene, etc.) (styrene, styrene-vinyltoluene copolymer, styrene-α-methylstyrene copolymer, etc.). ), A copolymer of a styrene monomer and a copolymerizable monomer (styrene-acrylonitrile copolymer (AS resin), styrene- (meth) acrylic acid copolymer, styrene- (meth) acrylic acid ester) Copolymers (MS resin, etc.), styrene-maleic anhydride copolymers, etc .; block copolymers, such as styrene-butadiene block copolymers, etc .; at least styrene-based monomers were graft-polymerized in the presence of a rubber component. Graft polymers such as high impact polystyrene (HIPS), acrylonitrile-butadiene-styrene copolymer ( ABS resin), a graft copolymer (AES resin, AAS resin) using a rubber component such as ethylene propylene rubber E, acrylic rubber A, chlorinated polyethylene C, vinyl acetate polymer in place of butadiene rubber B of this ABS resin. , ACS resin such as ACS resin), a graft copolymer using a (meth) acrylic monomer (such as methyl methacrylate) instead of acrylonitrile (for example, methyl methacrylate-butadiene rubber-styrene copolymer (MBS)). The resin solution includes a mixed solution of a solvent and a polymer alloy (for example, a copolymer of styrene and butadiene) containing a thermoplastic resin soluble in the solvent. .

As the olefin-based resin, a homopolymer or copolymer of α-C _2-6 olefin, for example, a homopolymer or copolymer of olefin such as polyethylene, polypropylene, ethylene-propylene copolymer, poly (methylpentene-1), Copolymer of olefin and copolymerizable monomer (ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl alcohol copolymer (EVOA), ethylene- (meth) acrylic acid copolymer, ethylene- ( (Meth) acrylic acid ester copolymers, ethylene- (meth) acrylic acid glycidyl copolymers and the like).

  Examples of the modified olefin-based resin include modified polyethylene (eg, chlorinated polyethylene, maleic anhydride modified polyethylene, etc.), modified polypropylene (eg, chlorinated polypropylene, maleic anhydride modified polypropylene, etc.) and the like.

Examples of the acrylic resin include (meth) acrylic monomers ((meth) acrylic acid, (meth) acrylic acid C _1-18 alkyl ester, (meth) acrylic acid hydroxy C _1-18 alkyl, (meth) acrylic acid). Glycidyl, (meth) acrylonitrile, etc.) or a copolymer thereof, for example, poly (meth) acrylic acid ester such as poly (meth) acrylic acid methyl, methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate -Acrylic acid ester- (meth) acrylic acid copolymer, methyl methacrylate- (meth) acrylic acid ester copolymer, (meth) acrylic monomer and other copolymerizable monomer (styrene-based monomer And the like) and copolymers.

  Examples of the halogen-containing resin include polyvinyl chloride resins (for example, polyvinyl chloride), vinyl chloride-vinyl acetate copolymers, vinylidene chloride resins, and the like.

  Examples of vinyl ester resins include homo- or copolymers of carboxylic acid vinyl esters (polyvinyl acetate, etc.).

  Examples of the thermoplastic polyurethane-based resin include polyester-type polyurethane-based resin and polyether-type polyurethane-based resin.

Examples of the polyester resin include aliphatic polyester, alicyclic polyester, aromatic polyester and the like. The aliphatic polyester can be formed with, for example, a first ester-forming component composed of alkylene glycol and alkanedicarboxylic acid, and at least one second ester-forming component selected from oxycarboxylic acid and lactone. The aliphatic polyester may be a copolymer of the first ester forming component and the second ester forming component. For example, poly (C _2-6 alkylene glycol-C _2-10 alkane-dicarboxylic acid ester) such as poly C _2-6 alkylene-oxalate, poly C _2-6 alkylene-succinate, and poly C _2-6 alkylene-adipate, Polyoxycarboxylic acid-based resin {for example, homo- or copolymer of oxycarboxylic acid and its lactone [for example, polyoxy C _2-10 carboxylic acid such as polyglycolic acid, polylactic acid, polycaprolactone, copolymers thereof (for example, , Glycolic acid-lactic acid copolymers, etc.], etc.], and these copolyesters (eg, polycaprolactone-polybutylene succinate copolymers, etc.) and the like. The aromatic polyester (or copolymerized polyester) is, for example, a copolyester containing a C _2-6 alkylene-C _6-12 arylate unit as a main component (for example, 50 mol% or more) (for example, the copolymerization component is oxyalkylene. And a polyoxy C _2-4 alkylene diol having a unit, a C _6-12 aliphatic dicarboxylic acid, a copolyester such as an asymmetric aromatic dicarboxylic acid such as isophthalic acid or phthalic acid). The content of the copolymerization component may be, for example, 5 to 50 mol%, preferably about 10 to 35 mol%.

  Examples of polyamide resins include aliphatic polyamide resins (eg, polyamide 46, polyamide 6, polyamide 66, etc.), copolyamides (eg, polyamide 6/11, polyamide 6/12, etc.); alicyclic polyamide resins. And so on.

  Examples of the polyether resin include polyphenylene ether resin and the like.

  Examples of the polycarbonate-based resin include bisphenol-based aromatic polycarbonates such as bisphenol A-type polycarbonate resin.

  Examples of the polysulfone resin include polysulfone resin, polyether sulfone resin, polyarylsulfone resin, alloys of these polysulfone resin and styrene resin, and the like.

  Examples of the thermoplastic polyimide resin include polyetherimide resin and polyamideimide resin.

  The thermoplastic resin also includes a thermoplastic elastomer (for example, a polyamide elastomer, a polyester elastomer, a polyolefin elastomer, a polyvinyl chloride elastomer, a thermoplastic polyurethane elastomer, etc.). These thermoplastic resins may be used alone or in combination of two or more.

  Among these thermoplastic resins, resins that are soluble in the above-mentioned preferable solvent and have a melting point lower than the decomposition temperature of cellulose, for example, styrene resin, modified olefin resin, acrylic resin, halogen-containing resin (polyvinyl chloride resin) ), Polyester resins (polyoxycarboxylic acid resins, polylactone resins) and the like are preferable. Styrene-based resins, modified olefin-based resins, halogen-containing resins, and polyester resins are often soluble in polar solvents, so resins using polar solvents (eg, ethers, ketones, esters, etc.) are used. A solution may be prepared. Further, in the method of the present invention, a condensation type resin (for example, a polyester type resin such as a polyoxycarboxylic acid type resin) can be preferably used since it can be applied without being in the form of an emulsion. A resin having a reactive group (for example, a hydroxyl group, a carboxyl group, an amino group, etc.) or a resin that generates a reactive group (for example, a polyester resin that generates a carboxyl group or a hydroxyl group by hydrolysis) In the kneading process, the resin and the cellulose nanofibers are chemically bonded (ester bond, ether bond, amide bond, etc.), and the reinforcing property of the resin can be effectively improved. Therefore, a resin having a reactive group, which is soluble in a polar solvent having a low boiling point (for example, ethers), has a small fiber diameter of cellulose nanofibers, and a kneaded composition having a high reinforcing effect by the nanofibers can be obtained. In many cases.

  Note that the thermoplastic resin is preferably a resin that is soluble in a solvent at room temperature (for example, about 20 to 30 ° C.), unlike polyethylene, polypropylene, or the like.

  Thus, the kneading composition of the present invention can be applied to any solvent-soluble resin, so that the range of application of the resin can be expanded.

[Cellulose nanofiber]
Cellulose nanofibers (or cellulose nanofibers) are cellulose fibers obtained by micronizing (or microfibrillating) cellulose (cellulose raw material) to the nano order. As the cellulose, lignin, pulp with a low content of non-cellulose components such as hemicellulose, for example, plant-derived cellulose raw material {for example, wood [for example, conifer (pine, fir, spruce, hemlock, cedar, etc.), hardwood ( Beech, hippo, poplar, maple, etc.), herbs (linen (linen, flax, Manila hemp, ramie, etc.), straw, bagasse, mitsumata, etc.), seed hair fiber (cotton linter, bombax cotton, kapok, etc.) , Bamboo, sugar cane, etc., animal-derived cellulosic raw materials (such as ascidian cellulose), bacterial-derived cellulosic raw materials (such as cellulose contained in nata de coco), and the like. These celluloses can be used alone or in combination of two or more kinds. Among these celluloses, wood pulp (for example, softwood pulp, hardwood pulp, etc.), seed hair fiber-derived pulp (for example, cotton linter pulp), and the like are preferable. The pulp may be mechanical pulp obtained by mechanically treating the pulp material, but chemical pulp obtained by chemically treating the pulp material is preferable because the content of the non-cellulose component is small.

  Further, the cellulose nanofibers may be nanofibers (oxidized cellulose nanofibers) that have been subjected to an oxidation treatment (for example, a treatment for oxidizing a methylol group at the C6 position to a carboxyl group), but in the present invention, oxidized cellulose is used. Cellulose nanofibers that have not been subjected to the oxidation treatment are preferable because they can be dispersed (or uniformly dispersed) in a resin even if they are not nanofibers. The kneaded composition formed of the cellulose nanofibers that has not been subjected to the oxidation treatment has no risk of the cellulose molecular chain being cleaved (or the degree of polymerization being lowered) due to the oxidation treatment, and there is no risk of coloring due to heating. Therefore, the properties of cellulose (for example, tensile strength, elastic modulus, low fiber expansion coefficient, etc.) can often be maintained. It should be noted that, even though it has not been subjected to an oxidation treatment process, the carboxyl groups and the like formed in the production process of pulp and the like may be contained in the cellulose nanofibers, but the cellulose nanofibers may not be practically oxidized. Good.

  The average fiber diameter of the cellulose nanofibers is, for example, 1 to less than 1000 nm (for example, 3 to 800 nm), preferably 5 to 500 nm (for example, 10 to 400 nm), and more preferably 50 to 300 nm (for example, 70 to 250 nm). May be If the average fiber diameter is too large, properties such as strength of the kneaded composition may deteriorate. The maximum fiber diameter of the cellulose nanofibers is, for example, 3 to less than 1000 nm (for example, 5 to 900 nm), preferably 10 to 700 nm (for example, 50 to 500 nm), and more preferably 70 to 400 nm (for example, 100 to 300 nm). ) May be about. In many cases, the cellulose fibers do not substantially include cellulose fibers having a fiber diameter of micrometer.

  Further, in the present invention, kneading in a state of permeating or impregnating the resin solution into the cellulose, because it can be suppressed that the shearing force acts directly on the cellulose fiber, it is possible to suppress the longitudinal cutting of the cellulose raw material, A fiber having a relatively long fiber length can be obtained. That is, the average fiber length of the cellulose fibers can be selected from the range of, for example, about 0.01 to 500 μm (for example, 0.1 to 400 μm), and is usually 1 μm or more (for example, 5 to 300 μm), preferably 10 μm or more ( For example, it may be 20 to 200 μm), more preferably 30 μm or more (for example, 50 to 150 μm).

  Furthermore, the ratio (aspect ratio) of the average fiber length to the average fiber diameter of cellulose (or cellulose fiber) is, for example, 5 or more (for example, about 5 to 10000), preferably 10 or more (for example, about 10 to 5000), More preferably, it may be 20 or more (for example, about 20 to 3000), particularly 50 or more (for example, 50 to 2000), 100 or more (for example, 100 to 1000), and further 200 or more (for example, 200). ~ 800). If the aspect ratio is too small, the reinforcing property of the resin may decrease.

  The cellulose (or cellulose fiber) may be a highly crystalline cellulose (or cellulose fiber), and the crystallinity of cellulose is, for example, 40 to 100% (for example, 50 to 100%), preferably It may be about 60 to 95%, more preferably about 70 to 90% (for example, 75 to 90%), and usually the crystallinity may be 60% or more. As the crystal structure of cellulose, for example, I-type, II-type, III-type, IV-type and the like can be exemplified, and the I-type crystal structure having low linear expansion characteristics and elastic modulus is preferable.

  Further, in the method of the present invention, by kneading in a resin solution, it may be possible to effectively apply a shearing force to the cellulose raw material while increasing the permeability of the resin solution into the cellulose nanofibers. Even in this case, it is possible to form a kneaded composition having a nano-order average fiber diameter and uniformly dispersed in a resin. In many cases, the kneaded composition usually does not substantially contain cellulose fibers having a fiber diameter of micrometer.

  On the other hand, from the viewpoint of improving the affinity (or dispersibility) for the resin, the cellulose nanofiber may be a modified cellulose nanofiber to which a modifier is bound. The modifier can be used as long as it is a modifier capable of binding to a hydroxy group of cellulose nanofibers and / or a carboxyl group formed in the manufacturing process of pulp, and in particular, a compound having a 9,9-bis (aryl) fluorene skeleton and the like. Is mentioned.

The compound having a 9,9-bis (aryl) fluorene skeleton (which may be referred to as a fluorene compound) has a 9,9-bisarylfluorene skeleton and comprises a carboxyl group or a reactive derivative thereof, an epoxy group and a hydroxyl group. It has at least one reactive group selected. Examples of the reactive derivative of the carboxyl group include alkoxycarbonyl groups (C _1-4 alkoxy-carbonyl groups such as methoxycarbonyl group and ethoxycarbonyl group), acid halide groups (haloformyl groups such as acid chloride group and acid bromide group). Can be exemplified. The epoxy group may be a glycidyl group as long as it contains an oxirane ring.

  A typical fluorene compound is represented by the following formula (1).

[In the formula, ring Z is an arene ring, X is a group represented by the following formula (2-1), (2-2) or (2-3), n is an integer of 1 to ³ , R ³ and R ⁴ represents a substituent, p represents an integer of 0 or 1 or more, and k represents an integer of 0 to 4].

(R ¹ represents a hydrogen atom or an alkyl group, R ² represents an alkylene group, and m 1 and m ² each represent 0 or an integer of 1 or more).

  In the above formula (1), examples of the arene ring represented by the ring Z include a monocyclic arene ring such as a benzene ring and a polycyclic arene ring. The polycyclic arene ring includes a condensed polycyclic arene. A ring (fused polycyclic hydrocarbon ring), a ring-collecting arene ring (ring-collecting aromatic hydrocarbon ring) and the like are included.

Examples of the fused polycyclic arene ring include a fused bicyclic arene (eg, fused bicyclic C _10-16 arene such as naphthalene) ring, a fused tricyclic arene (eg, anthracene, phenanthrene, etc.) ring, and the like. Examples include fused bi- to tetra-cyclic arene rings. Examples of preferable fused polycyclic arene ring include naphthalene ring and anthracene ring, and naphthalene ring is particularly preferable. The two rings Z may be the same or different rings.

Examples of the ring-collecting arene ring include a bilane ring, for example, a biphenyl ring, a binaphthyl ring, a biC _6-12 arene ring such as a phenylnaphthalene ring (1-phenylnaphthalene ring, 2-phenylnaphthalene ring, etc.), a terarene ring, for example, An example is a ter C _6-12 arene ring such as a terphenylene ring. Preferred ring-assembled arene rings include biC _6-10 arene rings, especially biphenyl rings.

In the formula (1), the alkyl group represented by R ¹ is a linear or branched C _1-6 such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, or a t-butyl group. An alkyl group can be illustrated. Preferred alkyl groups are C _1-4 alkyl groups, especially C _1-2 alkyl groups. m1 may be 0 or an integer of 1 or more (for example, 1 to 6, preferably 1 to 4, more preferably about 1 to 2). m1 may usually be 0 or 1-2.

The alkylene group R ² includes a linear or branched alkylene group, and examples of the linear alkylene group include a C _2-6 alkylene group (preferably, an ethylene group, a trimethylene group, a tetramethylene group, etc. A linear C _2-4 alkylene group, more preferably a linear C _2-3 alkylene group, particularly an ethylene group) can be exemplified, and examples of the branched chain alkylene group include a propylene group and a 1,2-butanediyl group. And a branched C _3-6 alkylene group such as a 1,3-butanediyl group (preferably a branched C _3-4 alkylene group, particularly a propylene group).

The number m2 of the oxyalkylene group (OR ² ) can be selected from the range of 0 or an integer of 1 or more (eg, 0 to 15, preferably 0 to 10), for example, 0 to 8 (eg, 1 to 8). , Preferably 0 to 5 (for example, 1 to 5), more preferably 0 to 4 (for example, 1 to 4), and particularly 0 to 3 (for example, 1 to 3), and usually 0 to It may be 2 (eg 0 or 1). When m2 is 2 or more, the alkylene groups R ² may be the same or different. Further, the types of the substituent R ² may be the same or different in the same or different ring Z.

  In the formula (1), the substitution number n of the group X may be the same or different depending on the kind of the ring Z and may be an integer of 1 or more, for example, 1 to 4, preferably 1 to 3, and more preferably May be 1 or 2, especially 1. The number of substitutions n may be the same or different in each ring Z.

  The group X can be substituted at an appropriate position on the ring Z. For example, when the ring Z is a benzene ring, the 2-, 3-, 4-position (particularly the 3-position and / or the -position of the phenyl group can be substituted. 4-position) is often substituted, and when ring Z is a naphthalene ring, it is often at the 5-8-position of the naphthyl group, for example, a naphthalene ring for the 9-position of fluorene. At the 1-position or 2-position (substitution with 1-naphthyl or 2-naphthyl), and the 1,5-position, 2,6-position or the like (particularly n Is 1, the group X is often substituted in the 2,6-position). Further, when n is 2 or more, the substitution position is not particularly limited. Further, in the ring-assembled arene ring Z, the substitution position of the group X is not particularly limited, and, for example, even if it is substituted with an arene ring bonded to the 9-position of fluorene and / or an arene ring adjacent to this arene ring. Good. For example, the 3-position or 4-position of the biphenyl ring Z may be bonded to the 9-position of fluorene, and when the 4-position of the biphenyl ring Z is bonded to the 9-position of fluorene, The substitution position may be any of 2-, 3-, 2'-, 3'-, 4'-positions, usually 2-, 3'-, 4'-positions, preferably 2-, 4 It may be substituted at the'-position (particularly at the 2-position).

In the above formula (1), as the substituent R ³ , a halogen atom (eg, fluorine atom, chlorine atom, bromine atom, iodine atom), an alkyl group (methyl group, ethyl group, propyl group, isopropyl group, butyl group, Linear or branched C _1-10 alkyl group such as s-butyl group and t-butyl group, preferably linear or branched C _1-6 alkyl group, more preferably linear or branched chain etc. Jo _{C 1-4} alkyl group), a cycloalkyl group (cyclopentyl group and _{C 5-10} cycloalkyl groups such as cyclohexyl group), an aryl group [phenyl group, alkylphenyl group (methylphenyl (tolyl) group, Dimethylphenyl (xylyl) group, etc., biphenyl group, C _6-12 aryl group such as naphthyl group], aralkyl group (C such as benzyl group, phenethyl group etc.) _6-10 aryl-C _1-4 alkyl group), an alkoxy group (for example, a methoxy group, an ethoxy group, a propoxy group, an n-butoxy group, an isobutoxy group, a t-butoxy group, or another linear or branched C). _1-10 alkoxy group), cycloalkoxy group (for example, C _5-10 cycloalkyloxy group such as cyclohexyloxy group), aryloxy group (for example, C _6-10 aryloxy group such as phenoxy group) , Aralkyloxy groups (eg, C _6-10 aryl-C _1-4 alkyloxy groups such as benzyloxy group), alkylthio groups (eg, methylthio group, ethylthio group, propylthio group, n-butylthio group, t-butylthio group) Groups such as C _1-10 alkylthio groups), cycloalkylthio groups (eg cyclohexyl) A C _5-10 cycloalkylthio group such as a ruthio group), an arylthio group (eg, a C _6-10 arylthio group such as a thiophenoxy group), an aralkylthio group (eg a C _6-10 aryl-C such as a benzylthio group). _1-4 alkylthio group, etc.), acyl group (for example, C _1-6 acyl group such as acetyl group), carboxyl group, alkoxycarbonyl group (for example, C _1-4 alkoxy-carbonyl group such as methoxycarbonyl group) , Nitro group, cyano group, dialkylamino group (eg, diC _1-4 alkylamino group such as dimethylamino group), dialkylcarbonylamino group (eg, diC _1-4 alkyl-carbonylamino group such as diacetylamino group) Groups, etc.) and the like.

Of these substituents R ³ , typically, a halogen atom, a hydrocarbon group (alkyl group, cycloalkyl group, aryl group, aralkyl group), an alkoxy group, an acyl group, a nitro group, a cyano group, a substituted amino group. And so on. Preferable substituent R ³ is an alkoxy group (linear or branched C _1-4 alkoxy group such as methoxy group), particularly an alkyl group (particularly linear or branched C ₁ such as methyl group). _1-4 alkyl groups) are preferred. When the substituent R ³ is an aryl group, the substituent R ³ together with the ring Z may form the ring-collecting arene ring. The types of the substituent R ³ may be the same or different in the same or different ring Z.

The coefficient p of the substituent R ³ can be appropriately selected depending on the type of the ring Z, and may be, for example, an integer of 0 to 8, an integer of 0 to 4, preferably 0 to 3 (for example, 0. It may be an integer of 2), especially 0 or 1. In particular, when p is 1, the ring Z may be a benzene ring, a naphthalene ring or a biphenyl ring, and the substituent R ³ may be a methyl group.

As the substituent R ⁴ , a cyano group, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, etc.), a carboxyl group, an alkoxycarbonyl group (for example, a C _1-4 alkoxy-carbonyl group such as a methoxycarbonyl group), an alkyl group (C _1-6 alkyl group such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, t-butyl group) and aryl group (C _6-10 aryl group such as phenyl group).

Among these substituents R ⁴ , a linear or branched C _1-4 alkyl group (in particular, a C _1-3 alkyl group such as a methyl group), a carboxyl group or a C _1-2 alkoxy-carbonyl group, cyano A group and a halogen atom are preferable. The substitution number k is an integer of 0 to 4 (for example, 0 to 3), preferably an integer of 0 to 2 (for example, 0 or 1), and particularly 0. The substitution numbers k may be the same or different from each other, and when k is 2 or more, the types of the substituents R ⁴ may be the same or different from each other, and the two benzene rings of the fluorene ring are substituted. The types of the substituents R ⁴ may be the same or different. The substitution position of the substituent R ⁴ is not particularly limited, and may be, for example, the 2-position to the 7-position (2-position, 3-position and / or 7-position) of the fluorene ring.

As a specific fluorene compound having the group X represented by the formula (2-1), 9,9-bis (carboxyaryl) fluorene in which n = 1, p = k = 0 and m1 = 0, for example, 9,9-bis (3-carboxyphenyl) fluorene, 9,9-bis (4-carboxyphenyl) fluorene, 9,9-bis (5-carboxynaphthyl) fluorene, 9,9-bis (6-carboxynaphthyl) 9,9-Bis (carboxy C _6-10 aryl) fluorene such as fluorene; 9,9-bis (carboxyalkyl-aryl) fluorene compound where n = 1, p = k = 0 and m1 = 1 to 3, for example , 9,9-bis (4- (carboxymethyl) phenyl) fluorene, 9,9-bis (4- (2-carboxyethyl) phenyl) fluorene, 9,9-bis (3- (ca) Ruboxoxymethyl) phenyl) fluorene, 9,9-bis (5- (carboxymethyl) naphthyl) fluorene, 9,9-bis (6- (carboxymethyl) naphthyl) fluorene and other 9,9-bis (carboxy C _1-6) Examples thereof include alkyl C _6-10 aryl) fluorene. These fluorene compounds can be used alone or in combination of two or more.

Specific examples of the fluorene compound having the group X represented by the formula (2-2) include 9,9-bis (glycidyloxyaryl) fluorene in which n = 1, p = k = 0, and m2 = 0. , For example, 9,9-bis (3-glycidyloxyphenyl) fluorene, 9,9-bis (4-glycidyloxyphenyl) fluorene, 9,9-bis (5-glycidyloxynaphthyl) fluorene , 9,9-bis (6-glycidyl-di-Cyr oxy naphthyl) fluorene such as 9,9-bis (Gurijishiruokishi _{C 6-10} aryl) fluorene; is n = 1, p = k = 0, m2 = 1~5 9,9-bis (glycidyloxy (poly) alkoxyaryl) fluorene, for example, 9,9-bis (4- (2-glycidyloxyethoxy) phenyl) fluorene, 9,9-bis (4- (2-glycidyl) Luoxypropoxy) phenyl) fluorene, 9,9-bis (5- (2-glycidyloxyethoxy) naphthyl) fluorene, 9,9-bis (6- (2-glycidyloxyethoxy) naphthyl) fluorene, etc. Roh 9,9-bis (Gurijishiruokishi _{(poly) C 2-4} alkoxy _{C 6-10} aryl) fluorene; n = 1, p = 1 , k = 0, m2 = is 0 9,9-bis (alkyl - glycidyl Disiloxyaryl) fluorene, for example 9,9-bis (C _1-4 alkyl-glycidyloxy C _6-10 aryl) fluorene such as 9,9-bis (3-methyl-4-glycidyloxyphenyl) fluorene. ; 9,9-bis (alkyl-glycidyloxy (poly) alkoxyaryl) fluorene with n = 1, p = 1, k = 0, m2 = 1-5, for example For example, 9,9-bis (3-methyl-4- (2-glycidyloxyethoxy) phenyl) fluorene and other 9,9-bis (C _1-4 alkyl-glycidyloxy (poly) C _2-4 alkoxy C _6-10 aryl) fluorene; 9,9-bis (aryl-glycidyloxyaryl) fluorene where n = 1, p = 0, k = 0, m2 = 0, for example 9,9-bis (4- phenyl-3-glycidyl-di-Sil oxyphenyl) fluorene such as 9,9-bis _{(C 6-10} aryl - Gurijishiruokishi _{C 6-10} aryl) fluorene; n = 1, p = 0 , k = 0, m2 = 1~ 5,9-bis (aryl-glycidyloxy (poly) alkoxyaryl) fluorene, for example 9,9-bis (4-phenyl-3- (2-glycidyloxyethoxy) phenyl. Is n = 2, p = 0, k = 0, m2 = 0; - ( Gurijishiruokishi (poly _{C 6-10 aryl) C 2-4} alkoxy _{C 6-10} aryl) fluorene) 9,9-bis fluorene 9,9-bis (di (Gurijishiruokishi) aryl) fluorene, e.g., 9,9-bis (3,4-di (Gurijishiruokishi) phenyl) 9,9-bis fluorene (di _{(Gurijishiruokishi) C 6-10} aryl ) Fluorene; 9,9-bis (di (glycidyloxy (poly) alkoxy) aryl) fluorene in which n = 2, p = 0, k = 0, m2 = 1-5, for example, 9,9-bis (3,3). 4-di (2-glycidyl-di-Sil oxy ethoxy)) phenyl) fluorene such as 9,9-bis (di (Gurijishiruokishi _{(poly) C 2-4 alkoxy) C 6-10} aryl) off Examples include luolene. These fluorene compounds can be used alone or in combination of two or more.

  The fluorene compound having a group represented by the formula (2-2) may be a monomer or a multimer (for example, a dimer or trimer). The fluorene compound having a glycidyl group usually contains at least a monomer, and may be, for example, a mixture of a monomer, a dimer and a trimer.

  Further, as a specific fluorene compound having the group X represented by the formula (2-3), a compound corresponding to the fluorene compound having the group X represented by the formula (2-3) (a glycidyloxy group is a hydroxyl group Compounds substituted for groups) and the like.

Among these fluorene compounds, preferable fluorene compounds include, for example, 9,9-bis (glycidyloxy C _6-10 aryl) fluorene and 9,9-bis (glycidyloxy (poly) C _2-4 alkoxy C _6-10 aryl. ) fluorene, 9,9-bis _{(C 1-4} alkyl - Gurijishiruokishi _{C 6-10} aryl) fluorene, 9,9-bis _{(C 1-4} alkyl - Gurijishiruokishi _{(poly) C 2-4} alkoxy _{C 6-10} aryl ) fluorene, 9,9-bis _{(C 6-10} aryl - Gurijishiruokishi _{C 6-10} aryl) fluorene, 9,9-bis _{(C 6-10} aryl - Gurijishiruokishi _{(poly) C 2-4} alkoxy _{C 6-10} aryl ) fluorene, 9,9-bis (di _{(Gurijishiruokishi) C 6-10} aryl) Fluorene, 9,9-bis (di (Gurijishiruokishi _{(poly) C 2-4 alkoxy) C 6-10} aryl) monomer of formula fluorene compound having a group X of the formula (2-2), such as fluorene , And multimers (dimers, trimers, etc.); 9,9-bis (hydroxy C _6-10 aryl) fluorene, 9,9-bis (hydroxy (poly) C _2-4 alkoxy C _6-10 aryl ) Fluorene, 9,9-bis ( _C1-4 alkyl-hydroxy _C6-10 aryl) fluorene, 9,9-bis ( _C1-4 alkyl-hydroxy (poly) _C2-4 alkoxy _C6-10 aryl) ) fluorene, 9,9-bis _{(C 6-10} aryl - hydroxy _{C 6-10} aryl) fluorene, 9,9-bis _{(C 6-10} aryl - hydroxy _{(poly) C 2-4} alkoxy Shi _{C 6-10} aryl) fluorene, 9,9-bis (dihydroxy _{C 6-10} aryl) fluorene, 9,9-bis (dihydroxy _{(poly) C 2-4 alkoxy) C 6-10} aryl) wherein the fluorene Examples thereof include a fluorene compound having the group X represented by the formula (2-3). In addition, "(poly) _C2-4 alkoxy" means that the repeating number m2 of the _C2-4 alkoxy group is an integer of 1 or more.

  The cellulose nanofibers (modified cellulose nanofibers) to which such a fluorene compound is bonded can exhibit excellent dispersibility (or affinity) with respect to the resin. Therefore, when the kneading composition contains the cellulose nanofibers to which the fluorene compound is bound, properties such as mechanical strength of the kneading composition can be improved. Furthermore, the average fiber diameter of the cellulose nanofibers can be reduced, probably because hydrogen bonds acting between the fibers can be relaxed in the process of microfibrillation of cellulose. Further, the cellulose nanofibers can effectively exhibit the effect of improving the dispersibility (or affinity) and the effect of reducing the fiber diameter even if the binding ratio of the fluorene compound is small. That is, the ratio of the modifying agent bonded to the cellulose nanofibers (may be referred to as a modification ratio) is 0.1 to 20% by weight with respect to the total amount of the modified cellulose nanofibers (the total amount of the cellulose nanofibers and the modifying agent). It can be selected from a range of about 0.2 to 15% by weight, preferably 0.5 to 10% by weight (eg 1 to 7% by weight), more preferably 1.5 to 5% by weight (eg 2 Up to about 4% by weight). If the modification rate is too high, the properties of the cellulose nanofibers (properties such as high strength, high elastic modulus and low linear expansion coefficient) may deteriorate. On the contrary, if it is too low, dispersibility (or miscibility) in the resin And the fiber diameter of the cellulose nanofibers may increase.

  The form of modification (or chemical modification) of the fluorene compound is usually a combination of a hydroxy group of cellulose nanofibers and / or a carboxy group formed in cellulose in the production process of pulp or the like and a hydroxy group of the fluorene compound. In many cases (ether bond and / or ester bond).

  The kneading composition of the present invention has a large proportion (content) of cellulose nanofibers and is useful as a masterbatch. The ratio of the cellulose nanofibers (or modified cellulose nanofibers) is, for example, 20% by weight or more (for example, 25 to 90% by weight), preferably 30% by weight or more (based on the total amount of the resin and the cellulose nanofibers). For example, it may be 35 to 70% by weight), more preferably 40% by weight or more (eg 40 to 60% by weight), and particularly 45% by weight or more (eg 45 to 55% by weight). If the proportion of the cellulose nanofibers is too small, the mechanical properties may deteriorate, and conversely, if it is too large, the moldability may deteriorate.

[Production method]
The kneading composition of the present invention can be obtained by kneading the resin solution of the thermoplastic resin and the cellulose raw material (or resin, solvent and cellulose raw material) and removing the solvent. In this method, the solvent can be removed by heating and the resin can be kneaded in a high-viscosity state while the resin solution permeates the cellulose nanofibers, so that the shearing force can be effectively applied. Probably because of this, it is possible to efficiently defibrate the cellulose raw material along with the kneading, to microfibrillate to a nano-order level, and to uniformly disperse the cellulose nanofibers in the resin. Further, even if the concentration of the cellulose nanofibers is high, the cellulose nanofibers can be uniformly dispersed in the resin in a short time without agglomeration of the cellulose nanofibers (or suppressing reaggregation of the cellulose nanofibers). Moreover, preparation of a dispersion liquid of cellulose nanofibers, preparation of an emulsion and the like are unnecessary, and the kneaded composition can be prepared by a one-step operation of kneading.

  As the cellulose raw material, the cellulose (or cellulose raw material) exemplified in the section of cellulose nanofiber can be used. The average fiber diameter of the cellulose raw material can be selected according to the type, and is, for example, 1 μm to 1 mm, preferably 5 to 500 μm (eg, 10 to 300 μm), and more preferably 20 to 100 μm (eg, 30 to 50 μm). It may be. The average fiber length of the cellulose raw material is, for example, 0.1 to 100 mm, preferably 0.5 to 50 mm (for example, 0.5 to 30 mm), and more preferably 1 to 10 mm (for example, 1 to 5 mm). It may be.

  The concentration of the thermoplastic resin solution can be appropriately selected depending on the solubility of the resin in the solvent and the like, and is, for example, 1 to 70% by weight (for example, 3 to 60% by weight), preferably 5 to 50% by weight (for example, 10 to 40% by weight), more preferably 15 to 30% by weight (for example, 15 to 25% by weight). If the solution concentration is too low or too high, the cellulose material may not be defibrated (or nanosized) sufficiently.

  The ratio of the cellulose raw material and the resin corresponds to the ratio (content) of the cellulose nanofibers to the total amount of the resin and the cellulose nanofibers in the kneading composition described above. It can be used in the ratio converted into the ratio of fiber.

  The kneading is not particularly limited as long as the resin solution and the cellulose raw material (or the resin, the solvent and the cellulose raw material) are kneaded, and the solvent in the system can be removed or the amount of the solvent can be controlled, and a conventional method such as a mixing roller or a kneader. , A Banbury mixer, an extruder (such as a single-screw or twin-screw extruder), and the like, and a twin-screw extruder or the like may be preferably used.

  The kneading step may be carried out in air or in an atmosphere of an inert gas (a rare gas such as nitrogen or argon) in an open system, and usually in a closed kneading system. When removing the solvent, the solvent may be evaporated (or evaporated) by heating using a deaerator installed in the kneader. In order to increase the shearing force, it is preferable to completely remove the solvent in the kneading process, but the solvent may remain in the range where the cellulose raw material can be defibrated to the nano level. The removal ratio of the solvent is, for example, 10% by weight or more (for example, 20 to 80% by weight), preferably 30% by weight or more (for example, 40 to 95% by weight), and more preferably 50% with respect to the solvent before removal. It may be about wt% or more (for example, 70 to 99 wt%), particularly about 80 wt% or more (for example, 90 to 99.9 wt%). After kneading, the residual solvent may be removed by a conventional method (for example, concentration) if necessary. If necessary, the solvent may be removed by reducing the pressure.

  Further, the composition may be kneaded (melt kneaded) while finally melting the thermoplastic resin. In the case of melt-kneading, a temperature equal to or higher than the melting point (or softening point) of the resin (usually equal to or higher than the boiling point of the solvent), for example, 100 to 270 ° C. (for example, 130 to 250 ° C.), preferably 150 to 220 ° C., more preferably The composition may be melt-kneaded at a temperature of about 170 to 200 ° C.

  In a preferred embodiment, the mixture is kneaded at a temperature below the boiling point of the solvent or near the boiling point of the solvent (for example, 40 to 100 ° C., preferably about 50 to 80 ° C.) for a certain time, and cellulose (or cellulose fibers) is added to the resin solution. And then heated to a temperature above the melting point (or softening point) of the resin (or a temperature above the melting point and below the decomposition temperature of cellulose) to increase the viscosity and shearing force of the resin, and kneading for a predetermined time. To be According to this method, cellulose nanofibers having a small fiber diameter can be uniformly dispersed in the resin in a short time. The kneading time is not particularly limited, but in the method of the present invention, since the kneading composition is often obtained in a short time, the kneading time is, for example, 1 minute to 5 hours (for example, 3 minutes to 3 hours), It may be preferably 5 minutes to 1 hour, more preferably about 8 to 30 minutes.

  In addition, in the case of producing a kneading composition containing a modified cellulose nanofiber in which a modifier is bonded to cellulose, after the modifier is bonded (or modified) to cellulose in the presence of a catalyst (for example, an acid) in advance ( This modified cellulose may be kneaded with the resin solution after the modified cellulose preparation step), but in the method of the present invention, the cellulose nanofibers and the modifier are effectively kneaded by kneading in the presence of the modifier. Since they can be bonded and there is no need to add a catalyst (for example, an acid catalyst such as hydrochloric acid), a kneaded composition (or masterbatch) containing modified cellulose nanofibers can be prepared simply and easily.

  The ratio of the modifier can be selected according to the modification ratio, and for example, is 1 to 50 parts by weight (for example, 3 to 45 parts by weight), preferably 5 to 40 parts by weight, relative to 100 parts by weight of the cellulose nanofibers. More preferably, it may be about 10 to 30 parts by weight (15 to 25 parts by weight). If the proportion of the modifier is too small, the defibration property of the cellulose may decrease.

  In the kneading step, each component may be added to the kneading system in plural times. For example, a composition containing at least a resin solution and a cellulose raw material may be kneaded, and a solid resin and / or a modifier may be added.

  After kneading, the kneaded composition may be obtained by a conventional drying method (for example, hot air drying, reduced pressure drying, etc.).

[Complex]
The composite (composite material) of the present invention contains the kneading composition (masterbatch) and another resin (second resin), and can be obtained by kneading (or mixing). The other resin (second resin) may be a resin having an affinity (or compatibility) with the thermoplastic resin of the kneading composition forming the masterbatch, and may be the same as or different from the resin forming the masterbatch. May be.

The second resin of the composite material may be the same as or different from the thermoplastic resin of the kneading composition. The second resin does not have to be soluble in the solvent, and by selecting a masterbatch according to the type of the second resin, a composite (composite material) formed of various resins can be obtained. Can be formed. The second resin may be either a thermoplastic resin or a thermosetting resin. Examples of the thermoplastic resin include addition polymerization resins [for example, olefin resins (poly α-C _2-10 olefins such as polyethylene, polypropylene and polymethylpentene), amorphous polyolefin resins (low density polyethylene, etc.). Amorphous polyolefins, cycloolefins such as cyclopentadiene-based resins and norbornene-based resins), ultra-high molecular weight polyolefin-based resins (eg ultra-high-molecular-weight polyethylene), vinyl-based resins (polyvinyl chloride, vinyl acetate-based resins) Etc.), aromatic vinyl resins [polystyrene, syndiotactic polystyrene, acrylonitrile-styrene resin, styrene-methyl methacrylate resin, acrylonitrile-butadiene-styrene copolymer (ABS resin), etc.], acrylic resins (for example, polymetha Homo- or copolymers of (meth) acrylic monomers such as methyl methacrylate, (meth) acrylic acid- (meth) acrylic acid ester, methyl methacrylate-styrene copolymers, etc., fluororesins (eg, Polytetrafluoroethylene, etc.), thermoplastic elastomer (eg, styrene-based thermoplastic elastomer, olefin-based thermoplastic elastomer, etc.), condensation polymerization-based resin (eg, polycarbonate-based resin (bisphenol A-type polycarbonate, etc.), polyester-based resin [for example, polyethylene terephthalate, polybutylene terephthalate, poly C _2-10 alkylene arylate such as polyethylene naphthalate, polycyclohexanedimethylene terephthalate, reinforced polyethylene terephthalate, these copolyesters, Poria Rate resins (polycondensation products of bisphenols such as bisphenol A and aromatic dicarboxylic acids such as phthalic acid), liquid crystal polyesters, polyoxycarboxylic acid resins (polyglycolic acid, polylactic acid, glycolic acid-lactic acid copolymerization) Etc.], polyacetal resin (polyoxymethylene homo or copolymer etc.), polyamide resin (for example, polyamide 6, polyamide 66, polyamide 46, polyamide 6T, polyamide 9T, polyamide 11, polyamide 12, polyamide MXD, etc.), Polysulfone-based resin (eg, polysulfone, polyethersulfone, etc.), poly (thio) ether-based resin [eg, polyphenylene ether-based resin (eg, polyphenylene ether, modified polyphenylene ether, etc.), polysulfide-based resin (Polyphenylene sulfide, polybiphenylene sulfide, etc.)], polyketone resin (polyether ketone, polyether ether ketone, polyphenylene sulfide ketone, etc.), polyimide resin (eg, polyimide, polyether imide, polyamide imide, etc.), polybenz Imidazole and the like}. The second resin may be engineering plastic or super engineering plastic.

  Examples of the thermosetting resin include amino resin (urea resin, melamine resin, phenol resin, furan resin, etc.), unsaturated polyester, diallyl phthalate resin, vinyl ester resin, epoxy resin, urethane resin, silicone resin, thermosetting resin. Examples of the resin include a polyimide resin. The second resin can be used alone or in combination of two or more kinds.

  In the composite, the ratio (content) of the cellulose nanofibers is, for example, 0.1 to 50% by weight (based on the total amount of the resin (the resin forming the masterbatch and the second resin) and the cellulose nanofibers ( For example, it may be 0.5 to 40% by weight), preferably 1 to 30% by weight (for example, 3 to 20% by weight), and more preferably about 5 to 15% by weight.

  Further, since the composite has excellent dispersibility of cellulose nanofibers, it does not need to include an additive such as a dispersant, and if necessary, various additives, for example, a stabilizer (an antioxidant, an ultraviolet absorbing agent). Agent, light stabilizer, heat stabilizer, etc.), antistatic agent, flame retardant (phosphorus flame retardant, halogen flame retardant, inorganic flame retardant, etc.), flame retardant aid, impact modifier, fluidity improvement It may contain agents, reinforcing materials (fillers and the like), colorants, lubricants, release agents, hue improvers, dispersants, antibacterial agents, preservatives and the like. You may use these additives individually or in combination of 2 or more types.

  Since the composite of the present invention is formed by a kneading composition (masterbatch) in which cellulose nanofibers are uniformly dispersed, the composition is a composition in which cellulose nanofibers having a small fiber diameter are dispersed without agglomeration of fibers. It has excellent characteristics such as high strength, high elastic modulus and low linear expansion characteristics. Therefore, it is useful for composite materials.

  The composite (composite material) can be obtained by kneading the masterbatch and the other resin according to the conventional method.

  The composite may be molded by, for example, an injection molding method, an injection compression molding method, an extrusion molding method, a transfer molding method, a blow molding method, a pressure molding method, or a casting molding method. The molded article of the composite is not limited to a two-dimensional structure (film, sheet, plate, etc.) but may have a three-dimensional structure (eg, tube, rod, tube, leather, hollow product, etc.). Further, the molded product may be a housing, a casing, or the like.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

(Observation of cellulose fiber)
The cellulose fibers were observed with a scanning electron microscope FE-SEM (JIM-6700F, manufactured by JEOL Ltd.) after removing excess resin and compounds adsorbed on cellulose in the solvent. The average fiber diameter was calculated by randomly selecting 50 fibers from the SEM image and averaging them.

(Modification rate of fluorene compound bonded to cellulose)
Modification ratio of fluorene compound (hereinafter fluorene modification ratio) of the Raman microscope (HORIBA JOBIN YVON Co., XploRA) performs Raman analysis using an aromatic ring (1604cm ^-1) and cellulose endocyclic CH (1375 cm ^{- It} was calculated from the intensity ratio (I ₁₆₀₄ / I ₁₃₇₅ ) of the absorption band to ¹ ). In the calculation, a diacetyl cellulose (manufactured by Daicel Corporation) film containing a predetermined amount of a fluorene compound was prepared by a solution casting method, and a calibration curve prepared from these intensity ratios (I ₁₆₀₄ / I ₁₃₇₅ ) was used. I was there. All samples were measured three times, and the average value of the values calculated from the results was taken as the fluorene modification rate.

(Tensile test)
The composites obtained in Examples 3 and 4 and Comparative Example 3 were hot press molded into a sheet having a thickness of 0.5 mm, and then annealed at 110 ° C. for 30 minutes to prepare a sheet. Then, it cut to the IEC540 standard size and used for the test. The tensile test was performed using "LTS-1kNB" manufactured by Minebea Co., Ltd. under the conditions of a chuck distance of 3 mm and a tensile speed of 5 mm / min.

(Coefficient of linear expansion)
The same 0.5 mm sheet as the tensile test sample was cut into a strip of 5 mm × 30 mm, and the sample was subjected to the test. The measurement was performed using a dynamic viscoelasticity measuring device ("Q-800" manufactured by TA Instruments Co., Ltd.), and a static load of 0.001 N was applied to the sample, and the temperature rising rate from room temperature to 170 ° C was 2 The temperature was raised at ° C / min, and the linear expansion coefficient [ppm / ° C] from 70 ° C to 100 ° C was calculated from the temperature-displacement curve.

(Example 1)
3.2 g of GP Cellulose fluff pulp (Grade 4800) cut into chips of about 3 mm square and 6.8 g of a solution of polylactic acid (REVODE110 manufactured by Hisun, hereinafter referred to as PLA) in dioxane (PLA fraction 20% by weight). Were blended with a lab kneader for 10 minutes to prepare a composition of pulp / dioxane / PLA = 3.2 / 5.44 / 1.36 (g / g / g). Furthermore, to 9 g of this composition, 0.6 g of 9,9-bis (4-glycidyloxyphenyl) fluorene (hereinafter, BPFG) and 2.24 g of PLA were added, and a twin-screw extruder (“Laboplast Mill”, Co., Ltd.) was added. White PLA / CNF (polylactic acid / cellulose nanofiber) masterbatch 1 (kneading composition) was obtained by kneading with Toyo Seiki. At this time, the initial 2 minutes were kneaded under the conditions of 80 ° C. and 300 revolutions, then the temperature was raised, and the kneading was performed under the conditions of 180 ° C. and 90 revolutions for 8 minutes. The solvent in the system was completely removed during the kneading process. The results of observing the defibration degree of CNF in the obtained PLA / CNF masterbatch 1 are shown in Fig. 1, which shows the average fiber diameter of defibrated fibers, the fluorene (BPFG) modification rate modified on the fiber surface, and the presence or absence of PLA modification. Shown in 1. In addition, regarding the presence or absence of PLA modification, the Fourier transform infrared spectrophotometer FT-IR (Nicolet, "MAGNA-IR 760") was used to measure the infrared spectroscopic spectrum, and the absorption peak of the carbonyl group of PLA It was judged by the presence or absence of (1750 cm ⁻¹ ) (shown in FIG. 2).

(Example 2)
A white PLA / CNF masterbatch 2 was obtained in the same manner as in Example 1 without adding BPFG in the kneading process using a twin-screw extruder (“Laboplast Mill”, manufactured by Toyo Seiki Co., Ltd.). . Fig. 3 shows the results of observing the defibration degree of CNF in the obtained PLA / CNF masterbatch 2, showing the average fiber diameter of defibrated fibers, the fluorene (BPFG) modification fraction modified on the fiber surface, and the presence or absence of PLA modification. It shows in Table 1. The presence or absence of modification of PLA was measured in the same manner as in Example 1 (shown in FIG. 2). Further, the masterbatch 1 obtained in Example 1 has a stronger absorption peak of carbonyl group than the masterbatch 2 obtained in Example 2, and thus more PLA is modified in Example 1. I found out.

(Comparative Example 1)
A masterbatch was prepared in the same manner as in Example 1 except that kneading was performed for 10 minutes at room temperature and 300 rpm in the kneading process using a twin-screw extruder (“Laboplast Mill”, manufactured by Toyo Seiki Co., Ltd.). Got 3. Moreover, in order to easily evaluate the pulp defibration degree in the obtained PLA / CNF masterbatch 3, it was diluted 10 times with dioxane and observed with a polarizing microscope (40 times). Many were seen (shown in Figure 4). The results of observing the pulp material with a polarizing microscope are shown in FIG.

(Comparative example 2)
A masterbatch was prepared in the same manner as in Example 1 except that the kneading process was carried out by using a twin-screw extruder (“Laboplast Mill”, manufactured by Toyo Seiki Co., Ltd.) at room temperature for 300 minutes under the conditions of 300 revolutions. Got 4. Further, when the pulp disentanglement degree was simply evaluated as in Comparative Example 1, a large amount of undisentangled pulp was found (shown in FIG. 6).

(Reference example 1)
In the kneading process using a twin-screw extruder (“Laboplast Mill”, manufactured by Toyo Seiki Co., Ltd.), PLA / PLA was prepared in the same manner as in Example 1 except that the kneading was performed for 120 minutes at room temperature and 300 rpm. CNF masterbatch 5 was obtained. In addition, when the defibration degree of the purple was simply evaluated in the same manner as in Comparative Example 1, undefibrated pulp was confirmed (shown in FIG. 7). The observation results of the CNF defibration degree of the obtained PLA / CNF masterbatch 5 are shown in FIG. 8, and Table 1 shows the average fiber diameter of defibrated fibers, the fluorene modification fraction modified on the fiber surface, and the presence or absence of PLA modification. Show. The presence or absence of modification of PLA was measured in the same manner as in Example 1 (shown in FIG. 2).

  From these results, it was found that in Examples 1 and 2, pulp (cellulosic raw material) can be defibrated to the nano level in the kneading process with the resin. Further, it was confirmed that Example 1 has a higher fluorene modification rate and PLA is modified as compared with Reference Example 1, and that it can be defibrated to the nano level in a short time of 10 minutes. It was also found that in Example 2 in which the fluorene compound (BPFG) was not added, similarly to the modification of PLA, it is possible to defibrate to the nano level by kneading for a short time. It was confirmed that in Example 1 in which BPFG was added, the average fiber diameter of the defibrated fibers was smaller and the PLA modification amount was larger.

(Example 3)
2.58 g of PLA / CNF masterbatch 1 (CNF fraction: 46.5% by weight, prepared in Example 1) dried at 110 ° C. overnight and 9.42 g of PLA were twin-screw extruder (“Laboplast mill”, ( A PLA composite material containing 10% by weight of CNF was prepared by kneading at 190 ° C. and 90 rotations for 5 minutes by Toyo Seiki Co., Ltd.). Table 2 shows the tensile measurement results and the linear expansion coefficient measurement results of the obtained composite material.

(Example 4)
2.40 g of PLA / CNF masterbatch 2 (CNF fraction: 50% by weight, prepared in Example 2) dried at 110 ° C. overnight and 9.60 g of PLA were twin-screw extruder (“Laboplast Mill”, Co., Ltd.). A PLA composite material containing 10% by weight of CNF was prepared by kneading with Toyo Seiki Co., Ltd.) under the conditions of 190 ° C. and 90 rotations for 5 minutes. Table 2 shows the tensile measurement results and the linear expansion coefficient measurement results of the obtained composite material.

(Comparative example 3)
12 g of PLA dried at 110 ° C. overnight was kneaded under the same conditions as in Example 3. Table 2 shows the tensile measurement results and the linear expansion coefficient measurement results of the obtained PLA.

  As is clear from the results in Table 2, the composite materials prepared using PLA / CNF master batches 1 and 2 have high tensile strength and elastic modulus, and can reduce the linear expansion coefficient. In addition, it was found that particularly excellent physical properties can be expressed in Example 3 using PLA / CNF masterbatch 1 using a modifier.

  The kneading composition (or masterbatch) of the present invention can be used for a wide range of applications, as a resin reinforcing material, an additive, a film or sheet material, and the like. In addition, since the composite (composite material) has excellent properties such as low linear expansion characteristics, high strength, and high elastic modulus, for example, various resin molded products [for example, packing materials for electric / electronic parts, building materials, etc. (Wall materials, etc.), Civil engineering materials, Agricultural materials, Packaging materials (Containers, cushioning materials, etc.), Living materials (Daily goods, etc.)], various materials such as liquid crystal display substrates and solar cell substrates; optical sheets, optical films ( For example, a polarizing film (and a polarizing plate protective film), a retardation film (for example, a retardation film having a reverse wavelength dispersion characteristic), an alignment film (alignment film), a viewing angle expansion (compensation) film, a diffusion plate (film), etc. ), Etc .; Space-related products due to their high strength [artificial satellites (artificial satellite bodies, parabolic antennas, solar battery frames, etc.), space shuttles (airframes, wings, remote control rods) Luggage compartment doors, etc.), aircraft parts (airframes, wings, tails, rudders, etc.), automobile parts (body, hoods, doors, drive shafts, etc.), sports equipment (golf shafts, tennis racket frames, etc.), leisure equipment ( It can also be used for fishing rods, etc.). Further, it can be used for molded members in various fields (for example, molded bodies such as caging and housings).

Claims (7)

A method for producing a kneading composition, in which cellulose nanofibers are dispersed in a solvent-soluble thermoplastic resin, and the ratio of the cellulose nanofibers is 20% by weight or more based on the total amount of the thermoplastic resin and the cellulose nanofibers. Wherein the solvent is water, hydrocarbons, halogenated hydrocarbons, alcohols, ethers, ketones, esters, amides, sulfoxides, nitriles, cellosolves, carbitols, cellosolve acetate. And at least one selected from the group consisting of carbitol acetates and carbonates;
The thermoplastic resin is at least one condensation-type thermoplastic resin selected from polyester-based resins, polyamide-based resins, polyether-based resins, polycarbonate-based resins, polysulfone-based resins, thermoplastic polyimide-based resins, and thermoplastic polyurethane-based resins. Including resin;
At least a resin solution in which the thermoplastic resin is dissolved in the solvent, and a cellulose containing a cellulose raw material having an average fiber diameter of 5 to 500 μm and an average fiber length of 0.5 to 50 mm and having no modifier bonded thereto. A method for producing, which comprises kneading a composition while removing a solvent, and further kneading the composition while melting a thermoplastic resin.   The method according to claim 1, wherein the composition is kneaded while being heated from a temperature not higher than the boiling point of the solvent to remove the solvent, and further the composition is kneaded while melting the thermoplastic resin.   Without adding a catalyst for binding a compound having a 9,9-bis (aryl) fluorene skeleton to cellulose, the resin solution and the cellulose were mixed in the presence of the compound having a 9,9-bis (aryl) fluorene skeleton. The method according to claim 1 or 2, wherein the composition containing the compound is kneaded.   Cellulose nanofibers having an average fiber diameter of 5 to 500 nm and an average fiber length of 10 μm or more, which does not include a cellulose fiber having a fiber diameter of micrometer, are used in an amount of 40 to 40 with respect to the total amount of the resin and the cellulose nanofibers. The method according to claim 1, wherein a kneading composition containing 60% by weight is produced.   The method according to any one of claims 1 to 4, wherein the solvent is at least one selected from hydrocarbons, halogenated hydrocarbons, alcohols, ethers, ketones, and esters.   The method according to claim 1, wherein the thermoplastic resin contains a polyester resin.   The method according to any one of claims 1 to 6, wherein the thermoplastic resin and the cellulose nanofibers are chemically bound to each other in the kneaded composition.