WO2019155929A1 - Fiber-reinforced resin composition and production method therefor - Google Patents

Fiber-reinforced resin composition and production method therefor Download PDF

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Publication number
WO2019155929A1
WO2019155929A1 PCT/JP2019/002785 JP2019002785W WO2019155929A1 WO 2019155929 A1 WO2019155929 A1 WO 2019155929A1 JP 2019002785 W JP2019002785 W JP 2019002785W WO 2019155929 A1 WO2019155929 A1 WO 2019155929A1
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WIPO (PCT)
Prior art keywords
fiber
water
cellulose
resin composition
reinforced resin
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PCT/JP2019/002785
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French (fr)
Japanese (ja)
Inventor
茂樹 森井
伸一 足立
信博 山田
裕也 田原
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長瀬産業株式会社
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Priority to JP2019570687A priority Critical patent/JP6994520B2/en
Publication of WO2019155929A1 publication Critical patent/WO2019155929A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K7/00—Use of ingredients characterised by shape
    • C08K7/02—Fibres or whiskers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L101/00—Compositions of unspecified macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L5/00—Compositions of polysaccharides or of their derivatives not provided for in groups C08L1/00 or C08L3/00

Definitions

  • the present invention relates to a fiber reinforced resin composition and a manufacturing method thereof, and a coated fiber and a manufacturing method thereof.
  • thermoplastic resins Since thermoplastic resins have excellent moldability, they are molded by various molding methods such as injection molding, extrusion molding, and blow molding, and are used for various applications.
  • a composite material in which strength and rigidity are improved by dispersing a filler in such a thermoplastic resin is known.
  • inorganic materials such as talc and glass fiber are filled. Strength and rigidity are improved as an agent.
  • inorganic materials such as talc and glass fiber have a large specific gravity of 2.5 to 2.7, so they deprive the resin of being lightweight, leave residue as sludge when incinerated, For reasons such as the possibility that the composite inorganic material may be scattered in the living space due to deterioration, it has been studied to convert the filler to another material.
  • fibers such as polyacrylonitrile fiber, aliphatic nylon fiber, aromatic nylon fiber, cellulose fiber, and polyvinyl alcohol fiber are used as a filler.
  • cellulose fibers have a specific gravity of about 1.5, which is lighter than inorganic materials, can be sintered by combustion, and are being studied for use as plant-derived renewable materials.
  • an object of the present invention is to provide a fiber reinforced resin composition capable of obtaining a molded body having sufficient strength and rigidity.
  • the present inventors unexpectedly added a water-soluble polysaccharide to a fiber-reinforced resin composition containing cellulose fibers and a thermoplastic resin composition, thereby unexpectedly reinforcing the fiber-reinforced resin composition.
  • the present invention has been completed by finding that the strength and rigidity of a molded product obtained from the product are improved.
  • a fiber reinforced resin composition containing a thermoplastic resin, cellulose fibers, and at least one water-soluble polysaccharide is provided.
  • the strength and rigidity of the molded body are improved as compared with a fiber reinforced resin composition containing cellulose fibers and not containing water-soluble polysaccharides.
  • a fiber reinforced resin composition containing cellulose fibers and not containing water-soluble polysaccharides.
  • Water-soluble polysaccharide forms a film on the surface of cellulose fiber. Therefore, when the molten thermoplastic resin and the cellulose fiber are kneaded, the polysaccharide coating suppresses recombination of the cellulose fibers and reduces the aggregation of the cellulose fibers, so that the cellulose fibers are contained in the thermoplastic resin. It is conceivable that it is easy to disperse uniformly and that the cellulose fibers are easily defibrated during kneading.
  • the water-soluble polysaccharide coating increases the adhesion between the thermoplastic resin and the cellulose fibers, thereby improving the strength and rigidity of the molded product.
  • the polysaccharide may be at least one selected from the group consisting of pullulan and dextrins.
  • the polysaccharide is preferably pullulan.
  • Pullulan has excellent film properties and adhesiveness among polysaccharides, and therefore can efficiently form a film firmly adhered to cellulose fibers. Furthermore, since pullulan has excellent lubricity, the cellulose fibers are easily dispersed uniformly in the thermoplastic resin. Pullulan is a Newtonian fluid having a relatively low viscosity among polysaccharides, and therefore has an advantage that it is easy to knead thermoplastic resin and cellulose fibers.
  • the thermoplastic resin is preferably a polyolefin resin or a polyamide resin.
  • Polyolefin resins and polyamide resins have the advantage of low specific gravity and light weight, but there is room for improvement in the strength and rigidity of the molded body. Therefore, by strengthening with cellulose fibers in the present invention, the strength and rigidity of the molded body are improved. The effect of improvement is exhibited more remarkably.
  • the polyolefin resin has advantages such as easy control of the molecular weight, various modifications by the copolymer, and establishment of a synthesis method.
  • the water-soluble polysaccharide may cover the surface of the cellulose fiber.
  • the fiber reinforced resin composition may contain 0.1 to 30 parts by weight of a water-soluble polysaccharide with respect to 100 parts by weight of cellulose fiber.
  • the present invention also provides a method for producing a fiber-reinforced resin composition, which includes a step of kneading a molten thermoplastic resin, cellulose fibers, and at least one water-soluble polysaccharide. According to the method of the present invention, it is not necessary to control a complex reaction, and the fiber-reinforced resin composition of the present invention can be produced simply and efficiently.
  • the surface of the cellulose fiber used in the step of kneading the molten thermoplastic resin, the cellulose fiber, and the water-soluble polysaccharide may be coated with the water-soluble polysaccharide in advance. It can. Since it is difficult for water to exist at the temperature at which the thermoplastic resin melts, and it is not easy to coat the cellulose fiber with a water-soluble polysaccharide, it is preferable to coat the thermoplastic resin before melting.
  • a step of heating the mixture containing the thermoplastic resin, the cellulose fiber, the water-soluble polysaccharide, and water to remove water from the mixture can be included.
  • the step of heating the mixture and the step of kneading can be performed in a kneader.
  • the heating step of the mixture may be performed outside the kneader.
  • the mixture before heating may contain 5 to 100 parts by weight of water with respect to 1 part by weight of the water-soluble polysaccharide.
  • the present invention also provides a coated fiber comprising cellulose fiber and a film of at least one water-soluble polysaccharide that coats the surface of the cellulose fiber.
  • the fiber reinforced resin composition of the present invention can be efficiently produced.
  • strength and rigidity can be shape
  • the present invention also provides a method for producing a coated fiber, comprising the step of coating cellulose fiber with at least one water-soluble polysaccharide. According to this method, the coated fiber of the present invention can be produced efficiently.
  • the coating step includes contacting the cellulose fiber with an aqueous solution containing the polysaccharide and drying the aqueous solution in contact with the cellulose fiber.
  • a fiber reinforced resin composition capable of giving sufficient strength and rigidity is provided.
  • the fiber reinforced resin composition of the present invention contains a thermoplastic resin, cellulose fibers, and a water-soluble polysaccharide.
  • a thermoplastic resin e.g., polyethylene glycol
  • cellulose fibers e.g., polypropylene glycol
  • a water-soluble polysaccharide e.g., polyethylene glycol
  • thermoplastic resin constitutes a base material on which cellulose fibers are dispersed.
  • the type of the thermoplastic resin is not particularly limited.
  • polyolefin resin, polyamide resin, polycarbonate resin, vinyl acetate resin, aromatic polyester resin, aliphatic polyester resin, polyether resin, vinyl chloride resin, fluorine resin, acrylic resin, A polystyrene resin, a polyacetal resin, etc. can be mentioned.
  • a thermoplastic resin can be used alone or in combination of two or more resins.
  • the thermoplastic resin used in the present invention preferably has a processing temperature of 280 ° C. or lower.
  • the processing temperature is 280 ° C. or lower, when the thermoplastic resin, the cellulose fiber, and the water-soluble polysaccharide are mixed at the processing temperature of the thermoplastic resin, and a molded product from the obtained fiber reinforced resin composition
  • the resin having such a processing temperature include a polyolefin resin and a polyamide resin among the resins listed above.
  • thermoplastic resins crystalline resins such as polyolefin resins and polyamide resins are preferable.
  • the thermoplastic resin includes a crystalline resin and an amorphous resin.
  • a crystalline resin is processed at a melting point +20 to 50 ° C.
  • an amorphous resin is processed at a glass transition temperature +100 to 120 ° C. . Therefore, in this specification, the processing temperature refers to a melting point +20 to 50 ° C. in the case of a crystalline resin, and refers to a glass transition temperature +100 to 120 ° C. in the case of an amorphous resin. Therefore, for example, when the thermoplastic resin is a crystalline resin, it preferably has a melting point of 260 ° C. or lower, more preferably 230 ° C. or lower.
  • the thermoplastic resin when the thermoplastic resin is an amorphous resin, the thermoplastic resin preferably has a glass transition temperature of 180 ° C. or lower, and more preferably has a glass transition temperature of 160 ° C. or lower. It is preferable to adjust the processing temperature to 280 ° C. or lower according to the melting point or glass transition temperature of the thermoplastic resin used.
  • the melting point and glass transition temperature of the thermoplastic resin can be adjusted by modifying the functional group of the monomer constituting the thermoplastic resin.
  • the thermoplastic resin is preferably a polyolefin resin or a polyamide resin. While polyolefin resins and polyamide resins have the advantage of being light in weight with a small specific gravity, there is room for improvement in the strength and rigidity of the molded body. Therefore, by strengthening with cellulose fibers in the present invention, the strength and rigidity of the molded body The effect of improvement is exhibited more remarkably. In addition, polyolefin resins and polyamide resins also have advantages such as easy control of molecular weight, various modifications by the copolymer, and establishment of a synthesis method.
  • polystyrene resin examples include olefin polymers such as low density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, and cyclic polyolefin, copolymers thereof, and modified products thereof.
  • the polyolefin resin may be a copolymer of ethylene and / or propylene and an ⁇ -olefin having 4 or more carbon atoms, such as an ethylene ⁇ -olefin copolymer or a propylene ⁇ -olefin copolymer.
  • polypropylene is particularly preferable because it is lightweight and has excellent heat resistance, chemical resistance, and moldability.
  • polypropylene include an ethylene / propylene block copolymer, an ethylene / propylene random copolymer, and a propylene / butene copolymer in addition to a homopolymer.
  • the thermoplastic resin is a polyolefin having an acid group, such as an acid-modified polyolefin to which maleic anhydride is added or a copolymer of maleic anhydride and an olefin such as an ⁇ -olefin in order to improve adhesion to cellulose fibers. Can be included.
  • the amount of the polyolefin having an acid group is preferably 0.5 to 50% by weight based on the whole thermoplastic resin.
  • polyamide resin polyamide polymers such as nylon 6, nylon 66, nylon 12, nylon 6,66 copolymer, nylon 6,12 copolymer, metaxylene adipamide / nylon 6 copolymer, and the like Denatured products can be mentioned.
  • nylon 6 and nylon 66 are preferably used.
  • the content of the thermoplastic resin in the fiber reinforced resin composition of the present invention is preferably 60 to 99 parts by weight with respect to 100 parts by weight of the fiber reinforced resin composition.
  • the content of the thermoplastic resin is preferably 65 to 99 parts by weight, more preferably 75 to 90 parts by weight.
  • the cellulose fibers are dispersed in the thermoplastic resin to increase the strength and rigidity of the molded body.
  • the cellulose fiber used in the present invention is a fiber containing cellulose as a main component.
  • the cellulose fiber source is not particularly limited, and various known materials can be used. Specifically, wood, plants other than wood (cotton, hemp, bamboo, kenaf, hemp, seaweed, etc.); animal fibers produced by sea squirts; bacterial cellulose produced by bacteria such as acetic acid bacteria; waste paper; rayon, polynosic, And regenerated cellulose such as cupra, lyocell, and acetate. Cellulose fibers can be used alone or in combination of two or more.
  • the form of the cellulose fiber used in the present invention is not particularly limited, and examples thereof include cellulose nanofiber, microfibrillated cellulose, and pulp.
  • KP kraft pulp
  • L material hardwood
  • N material coniferous tree
  • SP sulfide pulp
  • hemp and cotton which are representative examples of non-wood pulp, have a long fiber length, they are often entangled with the fiber itself when combined with a resin.
  • Cotton linter pulp a kind of cotton pulp, is easy to handle because it has a fiber length similar to wood pulp. The pulp is preferably defibrated.
  • Regenerated cellulose is characterized by easy fiber length control.
  • the cellulose nanofiber means cellulose having a fiber diameter of 3 nm to 35 nm or less, and the diameter of the cellulose nanofiber of the carboxylic acid-modified product produced with a TEMPO-based catalyst is also said to be 3 to 6 nm.
  • Microfibrillated cellulose is a cellulose fiber such as pulp that has been mechanically defibrated, which means cellulose fibers from micro to nano level, and such materials can also be used in the present invention as cellulose fibers. .
  • the average fiber length of the cellulose fibers in the resin is not particularly limited, but for example, the average fiber length of the cellulose fibers can be 0.2 to 20 mm. If the average fiber length of a cellulose fiber is the said range, the intensity
  • the average fiber diameter of the cellulose fibers in the resin is not particularly limited, but for example, the average fiber diameter of the cellulose fibers can be 15 nm to 30 ⁇ m.
  • the fiber diameter of the cellulose fiber can be appropriately adjusted by selecting the raw material of the cellulose fiber, the method of defibrating treatment, and the like.
  • the fiber length and fiber diameter of the cellulose fiber can be measured by, for example, a scanning electron microscope (SEM), an optical microscope or the like.
  • the content of the cellulose fiber in the fiber reinforced resin composition of the present invention is not particularly limited, but can be 0.5 to 75 parts by weight with respect to 100 parts by weight of the thermoplastic resin.
  • the cellulose fiber content is more preferably 1 to 50 parts by weight, and even more preferably 10 to 50 parts by weight.
  • the water-soluble polysaccharide forms a film on the surface (for example, side surface) of the cellulose fiber.
  • Polysaccharide refers to a sugar obtained by polymerizing a large number (eg, 10 or more) of monosaccharide molecules by glycosidic bonds. It is considered that a coating / coating effect that cannot be obtained with a monosaccharide and a disaccharide due to a small molecular weight (molecular length) can be obtained with a polysaccharide with a large molecular weight (molecular length).
  • Water-soluble means that 1 g of solid is powdered and then placed in water, and when it is shaken vigorously every 5 minutes at 100 ° C. or lower for 30 seconds, it dissolves in less than 30 mL of water within 30 minutes. Say. Even if the polysaccharide does not dissolve when the water temperature is low, if the water dissolves when the water is heated, a film can be formed on the cellulose fiber by heating. In the present invention, it is “water-soluble”.
  • the weight average molecular weight based on GPC of the water-soluble polysaccharide used in the present invention is preferably 100,000 or more, more preferably 200,000 or more from the viewpoint of easy formation of a film on cellulose fibers, and the upper limit is particularly high. Although it is not, it is preferable that it is 400,000 or less.
  • the type of water-soluble polysaccharide is not particularly limited, and any of synthetic polysaccharides, natural polysaccharides, and natural product modified polysaccharides can be used.
  • ⁇ -1,4-glucan (amylose, amylopectin, glycogen), ⁇ - 1,6-glucan (dextran), ⁇ -1,6-glucan (pustulan), ⁇ -1,3-glucan (eg curdlan, schizophyllan, etc.), ⁇ -1,3-glucan, ⁇ -1,2- Glucan, ⁇ -1,4-galactan, ⁇ -1,4-mannan, ⁇ -1,6-mannan, ⁇ -1,2-fructan (inulin), ⁇ -2,6-fructan (levan), ⁇ - Mention may be made of 1,4-xylan, ⁇ -1,3-xylan, pullulan, agarose, alginic acid and the like and their salts and derivatives.
  • starch containing amylose may be used.
  • Dextrins may also be used.
  • One or a combination of two or more water-soluble polysaccharides can be used.
  • cellulose since cellulose is not water-soluble, it is not included in the “water-soluble polysaccharide” in the present invention.
  • pullulan is a water-soluble compound having a structure in which maltotriose in which three molecules of glucose are linked by ⁇ -1,4 bonds is a structural unit and maltotriose is linked through ⁇ -1,6 bonds. Since pullulan has excellent coating properties and adhesiveness among polysaccharides, it can efficiently form a coating firmly adhered to cellulose fibers, and the effect of preventing aggregation of cellulose fibers becomes higher. Furthermore, since pullulan has excellent lubricity, the cellulose fibers are easily dispersed uniformly in the thermoplastic resin. Further, since it is a Newtonian fluid having a relatively low viscosity among the polysaccharides, it has an advantage of being easily kneaded when the thermoplastic resin and the cellulose fiber are kneaded.
  • the pullulan used in the present invention is not particularly limited in the obtaining method and type, but preferably has a weight average molecular weight based on GPC of 5,000 to 500,000, more preferably 50,000 to 400,000. .
  • a weight average molecular weight based on GPC of 5,000 to 500,000, more preferably 50,000 to 400,000.
  • dextrins are also preferable.
  • Dextrins can be obtained by hydrolysis of starch or glycogen, and are compounds having a molecular structure in which ⁇ -glucose is polymerized by ⁇ -1,4 or ⁇ -1,6 glycosidic bonds.
  • Dextrins include dextrin, maltodextrin, and powdered candy. Since dextrins also have excellent film properties and adhesiveness, a film firmly adhered to cellulose fibers can be efficiently formed, and the effect of preventing aggregation of cellulose fibers is enhanced.
  • the dextrins used in the present invention are not particularly limited in the obtaining method and type, but those having a dextrose equivalent (DE) of 10 or less are preferred, and those having a dextrose equivalent of 3.0 or less are more preferred. Further, those having a weight average molecular weight based on GPC of 5,000 to 500,000 are preferred, and those having a weight average molecular weight of 50,000 to 400,000 are more preferred. By using dextrins having a weight average molecular weight within the above range, it is considered that the coating effect on the cellulose fibers by the coating of dextrins becomes better.
  • DE dextrose equivalent
  • the content of the water-soluble polysaccharide in the fiber-reinforced resin composition of the present invention is not particularly limited, but is preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of cellulose fibers.
  • the polysaccharide can efficiently form a film on the cellulose fiber.
  • the water-soluble polysaccharide is more preferably 0.2 to 10 parts by weight with respect to 100 parts by weight of the cellulose fiber.
  • the fiber reinforced resin composition of the present invention may contain components other than the above-described thermoplastic resin, cellulose fiber, and water-soluble polysaccharide, if necessary.
  • components include various additives usually used in thermoplastic resin compositions, such as antioxidants, light stabilizers, ultraviolet absorbers, neutralizers, lubricants, antiblocking agents, dispersants, and fluidity.
  • additives such as an improving agent, a release agent, a flame retardant, a foaming agent, a colorant, a filler, a thickener, a low viscosity agent, and a crystal nucleating agent.
  • the content ratio of the fiber reinforced resin composition of these additives is preferably 30 parts by weight or less when the entire fiber reinforced resin composition is 100 parts by weight.
  • strength and rigidity of a molded object become high compared with the fiber reinforced resin composition which does not contain water-soluble polysaccharide although it contains a cellulose fiber. The reason is not clear, but the following can be considered.
  • Water-soluble polysaccharide forms a film on the surface of cellulose fiber. Therefore, when the melted thermoplastic resin and the cellulose fiber are mixed, the polysaccharide coating suppresses recombination of the cellulose fibers and reduces the aggregation of the cellulose fibers, and the cellulose fibers are contained in the thermoplastic resin. It is conceivable that it is easy to disperse uniformly and the cellulose fibers are easily defibrated during mixing.
  • the water-soluble polysaccharide coating increases the adhesion between the thermoplastic resin and the cellulose fiber, thereby improving the strength and rigidity.
  • the method for producing a fiber-reinforced resin composition of the present invention includes a step of kneading a molten thermoplastic resin, cellulose fibers, and a water-soluble polysaccharide. According to the method of the present invention, complicated reaction control is unnecessary, and the above-described fiber-reinforced resin composition can be produced simply and efficiently.
  • the above kneading can be performed by various kneaders such as a single or twin screw extruder, a roll, a Banbury mixer, a kneader, and a Brabender.
  • the cellulose fiber to be charged into the kneader may be an aqueous dispersion or a dry body.
  • the temperature at which the molten thermoplastic resin and the cellulose fiber are kneaded may be any temperature at which the thermoplastic resin dissolves.
  • the melting point of the crystalline thermoplastic resin can be +20 to 50 ° C.
  • the glass transition temperature of the amorphous thermoplastic resin can be set to +100 to 120 ° C.
  • the cellulose fiber is preferably defibrated in advance.
  • the method of defibrating treatment is not particularly limited, and examples thereof include physical treatment such as a grinder method, a high-pressure homogenizer method, an underwater counter impact method, a refiner method, an ultrasonic homogenizer method, a biaxial kneading method, a TEMPO oxidation method, and ozone. Chemical treatments such as an oxidation method and an enzyme treatment method, and combinations thereof can be performed.
  • the dry method there are generally two methods for defibrating sheet-like pulp, one of which is the dry method.
  • the dry method when the pulverized material is recovered by air blow while the pulp sheet is pulverized with a hammer mill or the like, the defibrated fiber can be obtained. Obstacles such as shortening the length may appear.
  • a special apparatus since the obtained defibrated material becomes a low-density cotton, a special apparatus may be required when it is put into the kneader together with the resin.
  • Another method of defibrating sheet-like pulp is a wet method.
  • pulp is well-familiar with water and can be fibrillated with a weak force in water, for example, with a normal stirring device or a pulper (stirring device).
  • a suction filtration method, a centrifugal separation method, a belt press method, or the like a fibrillated cellulose fiber (water dispersion) is obtained.
  • a kneader having a function of removing residual water such as a vent is required, but the crystallization degree is not lowered during defibration and the fiber length can be preserved.
  • the cellulose fiber concentration obtained by wet defibration is about 15 to 30% by weight for KP, about 20 to 35% by weight for cotton linter, and 5 to 20% by weight for microfibrillated cellulose. In the case of cellulose nanofibers, it can be 0.3 to 3% by weight.
  • a water-soluble polysaccharide film is formed on the surface of the cellulose fiber in advance.
  • the cellulose fiber and the cellulose fiber are brought into contact with the cellulose fiber by bringing the aqueous solution A containing a water-soluble polysaccharide into contact with the cellulose fiber, and drying the aqueous solution A in contact with the cellulose fiber by heating, decompression, or the like. It is possible to obtain a coated fiber having a water-soluble polysaccharide film covering the surface.
  • the aqueous solution A can be dried by a known method such as heating, reduced pressure, or natural drying.
  • the coating of the cellulose fiber with the water-soluble polysaccharide can also be performed in a kneader.
  • a mixture B of solid thermoplastic resin, cellulose fiber, water-soluble polysaccharide, and water may be kneaded in a kneader.
  • the mixture B is heated by the kneading of the mixture B, and the water in the mixture B can be removed out of the system as water vapor.
  • a water-soluble polysaccharide film is formed on the surface of the cellulose fiber.
  • the thermoplastic resin is melted, and the melted thermoplastic resin and cellulose fibers having a polysaccharide coating are kneaded.
  • the cellulose fiber contains 5 to 9% by weight of adsorbed water even in a dry body. Therefore, even when liquid water is not added to the kneader, the mixture containing the thermoplastic resin, cellulose fiber, and water-soluble polysaccharide is heated by shearing in the kneader, and the adsorbed water is separated from the cellulose fiber. Since it is desorbed to form free water, a mixture of thermoplastic resin, cellulose fiber, water-soluble polysaccharide, and water can be formed in the kneader. Therefore, the above-mentioned fiber reinforced resin composition can be produced without adding liquid water.
  • the aqueous solution A and the mixture B are 5 to 100 parts by weight with respect to 1 part by weight of the water-soluble polysaccharide. It is preferred to contain water.
  • a molded body can be produced from the above-described fiber-reinforced resin composition of the present invention.
  • the molding method various known methods can be used without particular limitation, and examples thereof include compression molding, injection molding, extrusion molding, extrusion lamination molding, rotational molding, calendar molding, vacuum molding, blow molding and the like.
  • the shape of the molded body is not particularly limited.
  • the molded product obtained from the fiber-reinforced resin composition of the present invention has sufficient strength and rigidity.
  • aqueous dispersion of cellulose fiber 1 A water slurry containing 2% by weight of NBKP (bleached kraft pulp made from softwood) was prepared. This was mechanically defibrated with a pulper (stirrer) to obtain an aqueous dispersion of cellulose fibers 1. Thereafter, excess water was removed by a centrifuge and concentrated to finally produce an aqueous dispersion of cellulose fibers 1 in which the concentration of cellulose fibers 1 was 25% by weight. The average fiber length of the cellulose fiber 1 was 2.8 mm, and the average fiber diameter was 25 ⁇ m.
  • Examples 1 to 6 In Examples 1 to 4, an aqueous dispersion of cellulose fiber 1, polypropylene (BC06C, manufactured by Nippon Polypro), acid-modified polypropylene (H1000P, manufactured by Toyobo), and powdered pullulan (food grade grade “Pullan”, manufactured by Hayashibara) Blended in the amounts shown in Table 1, supplied to a biaxial kneader with a vent, kneaded while discharging water vapor from the vent, and further kneaded while melting polypropylene at 230 ° C. to produce a fiber reinforced resin composition did. From the obtained fiber reinforced resin composition, an injection-molded article was prepared, and the flexural modulus was measured.
  • Example 5 was the same as Example 2 except that 20 parts by weight of a 10% by weight pullulan aqueous solution was blended to increase the amount of water. In Example 6, 2 parts by weight of a 10% by weight aqueous pullulan solution was blended.
  • Example 7 a fiber reinforced resin was prepared by the formulation shown in Table 1 in the same manner as in Example 2, except that a fluffy dried cellulose fiber 2 was used instead of the aqueous dispersion of cellulose fiber 1. did.
  • the cellulose fiber 2 does not contain liquid water but contains 7% by weight of adsorbed water.
  • Examples 8 to 10 were the same as Example 7 except that liquid water was further added according to the formulation shown in Table 1.
  • Example 11 was the same as Example 7 except that 20 parts by weight of a 10% by weight aqueous pullulan solution was blended.
  • Example 12 A cellulose fiber reinforced resin was prepared according to the formulation shown in Table 1 in the same manner as in Example 7 except that cellulose fiber 3 previously coated with pullulan was used instead of the combination of powdered pullulan and cellulose fiber 2. In addition, 2 parts of pullulan covers 20 parts of cellulose fibers.
  • Example 6 A fiber reinforced resin was produced in the same manner as in Example 1 except that 10 parts by weight of powdered trehalose was blended instead of the powdered pullulan.
  • Example 1 to 6 and Comparative Examples 1 to 4 an aqueous dispersion of cellulose fiber 1 obtained by wet defibrating treatment was used. According to the comparison between Examples 1 to 4 and Comparative Examples 1 to 4, the bending elastic modulus tended to improve as the amount of cellulose fiber increased regardless of whether or not pullulan was added. Is constant, the flexural modulus is significantly improved in each example with pullulan added as compared with each comparative example without pullulan added. It can also be seen that in the system to which pullulan is added, the degree of crystallinity of the resin increases as the amount of cellulose fibers increases.
  • Example 5 the crystallinity and the flexural modulus were obtained when the powdered pullulan was added to the cellulose fiber aqueous dispersion and when the aqueous pullulan solution was added to the cellulose fiber aqueous dispersion. It can be seen that it does not affect Further, when Example 5 and Example 6 were compared, the amount of pullulan added was one-tenth that of Example 5 in Example 6, but the same was true for the crystallinity of the resin and the flexural modulus. Showed the effect.
  • Comparative Example 6 in which 10 parts by weight of powdered trehalose was mixed in place of powdered pullulan, unlike Examples 1 to 4, the effects of increasing the crystallinity of the resin and improving the flexural modulus were observed. There wasn't.
  • Example 7 In Examples 7 to 11 and Comparative Example 5, dried cellulose fiber 2 obtained by dry defibrating treatment was used. Comparing Example 7 in which dried cellulose fiber 2 and pullulan in powder form were added and liquid water was not added, and Comparative Example 5 in which neither pullulan nor water was added, the crystallinity of polypropylene The bending elastic modulus of the molded body of Example 7 was slightly higher. Further, when Examples 7 to 10 are compared, when the same amount of cellulose fiber and the same amount of pullulan are used, as the amount of liquid water added increases, the degree of crystallinity of polypropylene increases, and the bending of the molded body increases. Elastic modulus increased.
  • Example 7 Even when liquid water is not added as in Example 7, the cellulose fibers contain moisture as adsorbed water, so that the pullulan is separated from the cellulose fibers by the process of heating. A film can be formed on the film, but it is considered that the effect of forming the film is enhanced by adding liquid water as in Examples 8 to 10.
  • Example 11 pullulan was added in the form of an aqueous solution. Compared with Example 9 in which the same amount of powder pullulan and almost the same amount of water were added, in Example 11, the crystallinity of polypropylene and the flexural modulus of the molded product were significantly increased. While there was no difference between Example 2 and Example 5 of wet defibrated cellulose fibers as described above, the reason why such difference appears in dry defibrated cellulose fibers is not clear, but wet defibrated cellulose Unlike fibers, dry defibrated cellulose fibers are considered more effective when added as an aqueous solution from the beginning.
  • Example 12 is an example in which cellulose fiber 3 in which cellulose fiber 2 was previously coated with pullulan was used for kneading.
  • Example 12 the same degree of polypropylene crystallinity and bending elastic modulus as in Examples 10 and 11 were obtained. That is, by using cellulose fibers pre-coated with pullulan, it was possible to effectively increase the flexural modulus of the molded body without adding water during kneading.
  • the present invention provides a fiber reinforced resin composition from which a molded article having excellent strength and rigidity can be obtained, and can be used in various fields.

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Abstract

A purpose of the present invention is to provide a fiber-reinforced resin composition capable of giving molded objects having sufficient strength and rigidity. The fiber-reinforced resin composition of the present invention comprises a thermoplastic resin, cellulose fibers, and at least one water-soluble polysaccharide.

Description

繊維強化樹脂組成物及びその製造方法Fiber reinforced resin composition and method for producing the same
　本発明は、繊維強化樹脂組成物及びその製造方法、並びに、被覆繊維及びその製造方法に関する。 The present invention relates to a fiber reinforced resin composition and a manufacturing method thereof, and a coated fiber and a manufacturing method thereof.
　熱可塑性樹脂は、優れた成形性を有することから、射出成形、押出成形、ブロー成形等の各種の成形方法で成形され、各種用途に利用されている。このような熱可塑性樹脂中に、充填剤を分散させて強度、剛性を向上した複合材料が知られており、例えば、特許文献１、２の方法では、タルク、ガラス繊維等の無機材料を充填剤として、強度、剛性を向上させている。 Since thermoplastic resins have excellent moldability, they are molded by various molding methods such as injection molding, extrusion molding, and blow molding, and are used for various applications. A composite material in which strength and rigidity are improved by dispersing a filler in such a thermoplastic resin is known. For example, in the methods of Patent Documents 1 and 2, inorganic materials such as talc and glass fiber are filled. Strength and rigidity are improved as an agent.
　しかし、タルクやガラス繊維といった無機材料は、比重が２．５～２．７と大きいため、軽量であるという樹脂の特性を奪うこと、焼却処分する際にスラッジとして残渣物を残すこと、樹脂の劣化により、複合されている無機材料が生活空間に飛散するおそれがあること等の理由から、充填材を他の材料へ転換することが検討されている。 However, inorganic materials such as talc and glass fiber have a large specific gravity of 2.5 to 2.7, so they deprive the resin of being lightweight, leave residue as sludge when incinerated, For reasons such as the possibility that the composite inorganic material may be scattered in the living space due to deterioration, it has been studied to convert the filler to another material.
　このような材料として、特許文献３では、充填剤としてポリアクリロニトリル繊維、脂肪族ナイロン繊維、芳香族ナイロン繊維、セルロース繊維、ポリビニルアルコール繊維等の繊維を用いている。 As such a material, in Patent Document 3, fibers such as polyacrylonitrile fiber, aliphatic nylon fiber, aromatic nylon fiber, cellulose fiber, and polyvinyl alcohol fiber are used as a filler.
　繊維の中でもセルロース繊維の比重は１．５程度で無機材料より軽く、燃焼により焼結することができるほか、植物由来の再生可能な材料として、その利用が検討されている。 Among the fibers, cellulose fibers have a specific gravity of about 1.5, which is lighter than inorganic materials, can be sintered by combustion, and are being studied for use as plant-derived renewable materials.
特開２００５－２６４０３３号公報JP 2005-264033 A 特開２０１７－６１５９５号公報JP 2017-61595 A 特開平０５－２４７２６３号公報JP 05-247263 A
　しかしながら、熱可塑性樹脂中にセルロース繊維を分散させた従来の繊維強化樹脂組成物から得られた成形体の強度及び剛性（弾性率）は十分ではなかった。 However, the strength and rigidity (elastic modulus) of a molded product obtained from a conventional fiber reinforced resin composition in which cellulose fibers are dispersed in a thermoplastic resin are not sufficient.
　したがって、本発明においては、十分な強度及び剛性を有する成形体を得ることができる、繊維強化樹脂組成物を提供することを目的とする。 Therefore, an object of the present invention is to provide a fiber reinforced resin composition capable of obtaining a molded body having sufficient strength and rigidity.
　本発明者らは、鋭意検討した結果、セルロース繊維と熱可塑性樹脂組成物とを含む繊維強化樹脂組成物に対して、さらに水溶性の多糖類を加えることにより、予想外にも繊維強化樹脂組成物から得られる成形体の強度及び剛性が向上することを見出し、本発明を完成させた。 As a result of intensive studies, the present inventors unexpectedly added a water-soluble polysaccharide to a fiber-reinforced resin composition containing cellulose fibers and a thermoplastic resin composition, thereby unexpectedly reinforcing the fiber-reinforced resin composition. The present invention has been completed by finding that the strength and rigidity of a molded product obtained from the product are improved.
　すなわち、本発明においては、熱可塑性樹脂と、セルロース繊維と、少なくとも一つの水溶性の多糖類とを含む、繊維強化樹脂組成物を提供する。 That is, in the present invention, a fiber reinforced resin composition containing a thermoplastic resin, cellulose fibers, and at least one water-soluble polysaccharide is provided.
　本発明によれば、セルロース繊維を含み水溶性の多糖類を含まない繊維強化樹脂組成物と比べて、成形体の強度及び剛性が向上する。その作用機序は明らかではないが例えば以下の理由が考えられる。 According to the present invention, the strength and rigidity of the molded body are improved as compared with a fiber reinforced resin composition containing cellulose fibers and not containing water-soluble polysaccharides. Although the mechanism of action is not clear, for example, the following reasons can be considered.
　水溶性の多糖類は、セルロース繊維の表面に被膜を形成する。したがって、溶融した熱可塑性樹脂と、セルロース繊維とが混練される際に、多糖類の被膜によりセルロース繊維同士の再結合が抑制されてセルロース繊維同士の凝集が低減され、セルロース繊維が熱可塑性樹脂中で均一に分散しやすくなること、混練中にセルロース繊維が解繊されやすくなることが考えられる。 Water-soluble polysaccharide forms a film on the surface of cellulose fiber. Therefore, when the molten thermoplastic resin and the cellulose fiber are kneaded, the polysaccharide coating suppresses recombination of the cellulose fibers and reduces the aggregation of the cellulose fibers, so that the cellulose fibers are contained in the thermoplastic resin. It is conceivable that it is easy to disperse uniformly and that the cellulose fibers are easily defibrated during kneading.
　また、水溶性の多糖類の被膜が熱可塑性樹脂とセルロース繊維との密着性を高め、これにより成形体の強度及び剛性が向上することも考えられる。 It is also conceivable that the water-soluble polysaccharide coating increases the adhesion between the thermoplastic resin and the cellulose fibers, thereby improving the strength and rigidity of the molded product.
　前記多糖類は、プルラン及びデキストリン類から成る群から選択される少なくとも一つであることができる。 The polysaccharide may be at least one selected from the group consisting of pullulan and dextrins.
　特に、多糖類はプルランであることが好ましい。プルランは多糖類の中でも優れた被膜性、接着性を有するため、セルロース繊維に強固に密着した被膜を効率的に形成することができる。さらに、プルランは優れた潤滑性を有するため、セルロース繊維が熱可塑性樹脂中で均一に分散しやすくなる。また、プルランは多糖類の中でも比較的低粘性のニュートン流体であることから、熱可塑性樹脂とセルロース繊維とを混練しやすいという利点を有する。 In particular, the polysaccharide is preferably pullulan. Pullulan has excellent film properties and adhesiveness among polysaccharides, and therefore can efficiently form a film firmly adhered to cellulose fibers. Furthermore, since pullulan has excellent lubricity, the cellulose fibers are easily dispersed uniformly in the thermoplastic resin. Pullulan is a Newtonian fluid having a relatively low viscosity among polysaccharides, and therefore has an advantage that it is easy to knead thermoplastic resin and cellulose fibers.
　熱可塑性樹脂はポリオレフィン樹脂又はポリアミド樹脂であることが好ましい。ポリオレフィン樹脂及びポリアミド樹脂は比重が小さく軽量であるという利点を有する反面、成形体の強度及び剛性には向上の余地があったため、本発明においてセルロース繊維で強化することにより、成形体の強度及び剛性向上という効果がより顕著に発揮される。また、ポリオレフィン樹脂は、分子量のコントロールが容易である、共重合体による多様な変性が可能である、合成方法が確立されている等の利点も有する。 The thermoplastic resin is preferably a polyolefin resin or a polyamide resin. Polyolefin resins and polyamide resins have the advantage of low specific gravity and light weight, but there is room for improvement in the strength and rigidity of the molded body. Therefore, by strengthening with cellulose fibers in the present invention, the strength and rigidity of the molded body are improved. The effect of improvement is exhibited more remarkably. In addition, the polyolefin resin has advantages such as easy control of the molecular weight, various modifications by the copolymer, and establishment of a synthesis method.
　上記繊維強化樹脂組成物において、上記水溶性の多糖類は、上記セルロース繊維の表面を被覆していてもよい。 In the fiber reinforced resin composition, the water-soluble polysaccharide may cover the surface of the cellulose fiber.
　上記繊維強化樹脂組成物は、１００重量部のセルロース繊維に対して、０．１～３０重量部の水溶性の多糖類を含むことができる。 The fiber reinforced resin composition may contain 0.1 to 30 parts by weight of a water-soluble polysaccharide with respect to 100 parts by weight of cellulose fiber.
　また、本発明は、溶融した熱可塑性樹脂と、セルロース繊維と、少なくとも一つの水溶性の多糖類とを混練するステップを含む、繊維強化樹脂組成物の製造方法も提供する。本発明の方法によれば、複雑な反応の制御が不要であり、簡便かつ効率的に、上記本発明の繊維強化樹脂組成物を製造することができる。 The present invention also provides a method for producing a fiber-reinforced resin composition, which includes a step of kneading a molten thermoplastic resin, cellulose fibers, and at least one water-soluble polysaccharide. According to the method of the present invention, it is not necessary to control a complex reaction, and the fiber-reinforced resin composition of the present invention can be produced simply and efficiently.
　ここで、溶融した熱可塑性樹脂と、セルロース繊維と、水溶性の多糖類とを混練するステップに供される上記セルロース繊維の表面には、あらかじめ上記水溶性の多糖類が被覆されていることができる。熱可塑性樹脂が溶融する温度では水が存在しにくく、水溶性の多糖類でのセルロース繊維の被覆が容易でないため、熱可塑性樹脂の溶融前に被覆することが好適である。 Here, the surface of the cellulose fiber used in the step of kneading the molten thermoplastic resin, the cellulose fiber, and the water-soluble polysaccharide may be coated with the water-soluble polysaccharide in advance. it can. Since it is difficult for water to exist at the temperature at which the thermoplastic resin melts, and it is not easy to coat the cellulose fiber with a water-soluble polysaccharide, it is preferable to coat the thermoplastic resin before melting.
　この場合、上記混練するステップの前に、上記熱可塑性樹脂、上記セルロース繊維、上記水溶性の多糖類、及び、水を含む混合物を加熱して上記混合物から水を除去するステップを含むことができる。 In this case, before the kneading step, a step of heating the mixture containing the thermoplastic resin, the cellulose fiber, the water-soluble polysaccharide, and water to remove water from the mixture can be included. .
　これにより、水溶性の多糖類が、セルロース繊維の表面のより広範囲に行き渡り、セルロース繊維に密着して被膜を形成することができる。得られた繊維強化樹脂組成物からは、より強度及び剛性の高い成形体を作製することができる。 This allows the water-soluble polysaccharide to spread over a wider area on the surface of the cellulose fiber and to form a film in close contact with the cellulose fiber. From the obtained fiber reinforced resin composition, a molded product having higher strength and rigidity can be produced.
　上記混合物を加熱するステップ及び上記混練するステップを、混練機内で行うことができる。一方、上記混合物の加熱ステップを、混練機外で行ってもよい。 The step of heating the mixture and the step of kneading can be performed in a kneader. On the other hand, the heating step of the mixture may be performed outside the kneader.
　ここで、加熱前の上記混合物は、１重量部の上記水溶性の多糖類に対して、５～１００重量部の水を含むことができる。 Here, the mixture before heating may contain 5 to 100 parts by weight of water with respect to 1 part by weight of the water-soluble polysaccharide.
　また、本発明は、セルロース繊維と、前記セルロース繊維の表面を被覆する少なくとも一つの水溶性の多糖類の膜と、を備える被覆繊維を提供する。本発明の被覆繊維を用いることにより、上記本発明の繊維強化樹脂組成物を効率的に製造することができる。また、得られる繊維強化樹脂組成物からは、優れた強度及び剛性を有する成形体を成形できる。 The present invention also provides a coated fiber comprising cellulose fiber and a film of at least one water-soluble polysaccharide that coats the surface of the cellulose fiber. By using the coated fiber of the present invention, the fiber reinforced resin composition of the present invention can be efficiently produced. Moreover, the molded object which has the outstanding intensity | strength and rigidity can be shape | molded from the fiber reinforced resin composition obtained.
　また、本発明は、セルロース繊維を少なくとも一つの水溶性の多糖類で被覆するステップを含む、被覆繊維の製造方法を提供する。本方法によれば、上記本発明の被覆繊維を効率的に製造することができる。 The present invention also provides a method for producing a coated fiber, comprising the step of coating cellulose fiber with at least one water-soluble polysaccharide. According to this method, the coated fiber of the present invention can be produced efficiently.
　上記方法においては、上記被覆するステップは、上記セルロース繊維に上記多糖類を含む水溶液を接触させること、及び、前記セルロース繊維に接触した上記水溶液を乾燥させること、を含むことが好ましい。水溶性の多糖類を水に溶解させて水溶液の形態にしてからセルロース繊維と接触させることにより、多糖類を、セルロース繊維の表面のより広範囲に行き渡らせることができる。 In the above method, it is preferable that the coating step includes contacting the cellulose fiber with an aqueous solution containing the polysaccharide and drying the aqueous solution in contact with the cellulose fiber. By dissolving the water-soluble polysaccharide in water to form an aqueous solution and then bringing it into contact with the cellulose fiber, the polysaccharide can be spread more widely on the surface of the cellulose fiber.
　本発明によれば、十分な強度及び剛性を与えることができる繊維強化樹脂組成物が提供される。 According to the present invention, a fiber reinforced resin composition capable of giving sufficient strength and rigidity is provided.
　以下、本発明の実施の形態を、具体的に説明する。 Hereinafter, embodiments of the present invention will be specifically described.
（繊維強化樹脂組成物）
　本発明の繊維強化樹脂組成物は、熱可塑性樹脂と、セルロース繊維と、水溶性の多糖類とを含む。以下、それぞれの構成要素について説明する。 (Fiber reinforced resin composition)
The fiber reinforced resin composition of the present invention contains a thermoplastic resin, cellulose fibers, and a water-soluble polysaccharide. Hereinafter, each component will be described.
（熱可塑性樹脂）
　本発明の繊維強化樹脂組成物において、熱可塑性樹脂はセルロース繊維を分散させる基材を構成する。熱可塑性樹脂の種類は特に限定されないが、例えば、ポリオレフィン樹脂、ポリアミド樹脂、ポリカーボネート樹脂、酢酸ビニル樹脂、芳香族ポリエステル樹脂、脂肪族ポリエステル樹脂、ポリエーテル樹脂、塩化ビニル樹脂、フッ素樹脂、アクリル樹脂、ポリスチレン樹脂、ポリアセタール樹脂等を挙げることができる。熱可塑性樹脂は、１種類または２種類以上の樹脂を組み合わせて用いることができる。 (Thermoplastic resin)
In the fiber reinforced resin composition of the present invention, the thermoplastic resin constitutes a base material on which cellulose fibers are dispersed. The type of the thermoplastic resin is not particularly limited. For example, polyolefin resin, polyamide resin, polycarbonate resin, vinyl acetate resin, aromatic polyester resin, aliphatic polyester resin, polyether resin, vinyl chloride resin, fluorine resin, acrylic resin, A polystyrene resin, a polyacetal resin, etc. can be mentioned. A thermoplastic resin can be used alone or in combination of two or more resins.
　本発明に用いる熱可塑性樹脂は、２８０℃以下の加工温度を有することが好ましい。加工温度が２８０℃以下であれば、熱可塑性樹脂の加工温度において、熱可塑性樹脂、セルロース繊維、及び、水溶性の多糖類を混合する際、及び、得られた繊維強化樹脂組成物から成形体を作製する際に、セルロース繊維が劣化したり分解されたりせずに樹脂組成物中に残存しやすくなるため、より強度が向上した成形体が得やすくなる。このような加工温度を有する樹脂としては、上記列挙した樹脂の中で、ポリオレフィン樹脂、ポリアミド樹脂等を挙げることができる。熱可塑性樹脂のなかでも、ポリオレフィン樹脂及びポリアミド樹脂の様な結晶性樹脂が好適である。
　なお、熱可塑性樹脂には、結晶性樹脂と非晶性樹脂があり、一般的に、結晶性樹脂は融点＋２０～５０℃で、非晶性樹脂はガラス転移温度＋１００～１２０℃で加工される。
　したがって、本明細書において、加工温度とは、結晶性樹脂の場合、融点＋２０～５０℃を指し、非晶性樹脂の場合、ガラス転移温度＋１００～１２０℃を指す。
　したがって、例えば、熱可塑性樹脂が結晶性樹脂の場合、２６０℃以下の融点を有することが好ましく、２３０℃以下の融点を有することがより好ましい。また、例えば、熱可塑性樹脂が非結晶性樹脂の場合、１８０℃以下のガラス転移温度を有することが好ましく、１６０℃以下のガラス転移温度を有することがより好ましい。
　用いる熱可塑性樹脂の融点又はガラス転移温度に応じて、加工温度を２８０℃以下になるように調整することが好ましい。
　熱可塑性樹脂の融点やガラス転移温度は、熱可塑性樹脂を構成する単量体の官能基を修飾することによって、調整することができる。 The thermoplastic resin used in the present invention preferably has a processing temperature of 280 ° C. or lower. When the processing temperature is 280 ° C. or lower, when the thermoplastic resin, the cellulose fiber, and the water-soluble polysaccharide are mixed at the processing temperature of the thermoplastic resin, and a molded product from the obtained fiber reinforced resin composition When the is manufactured, the cellulose fibers are easily left in the resin composition without being deteriorated or decomposed, so that a molded body with improved strength can be easily obtained. Examples of the resin having such a processing temperature include a polyolefin resin and a polyamide resin among the resins listed above. Among thermoplastic resins, crystalline resins such as polyolefin resins and polyamide resins are preferable.
The thermoplastic resin includes a crystalline resin and an amorphous resin. Generally, a crystalline resin is processed at a melting point +20 to 50 ° C., and an amorphous resin is processed at a glass transition temperature +100 to 120 ° C. .
Therefore, in this specification, the processing temperature refers to a melting point +20 to 50 ° C. in the case of a crystalline resin, and refers to a glass transition temperature +100 to 120 ° C. in the case of an amorphous resin.
Therefore, for example, when the thermoplastic resin is a crystalline resin, it preferably has a melting point of 260 ° C. or lower, more preferably 230 ° C. or lower. For example, when the thermoplastic resin is an amorphous resin, the thermoplastic resin preferably has a glass transition temperature of 180 ° C. or lower, and more preferably has a glass transition temperature of 160 ° C. or lower.
It is preferable to adjust the processing temperature to 280 ° C. or lower according to the melting point or glass transition temperature of the thermoplastic resin used.
The melting point and glass transition temperature of the thermoplastic resin can be adjusted by modifying the functional group of the monomer constituting the thermoplastic resin.
　本発明においては、熱可塑性樹脂がポリオレフィン樹脂又はポリアミド樹脂であることが好ましい。ポリオレフィン樹脂やポリアミド樹脂は比重が小さく軽量であるという利点を有する反面、成形体の強度及び剛性には向上の余地があったため、本発明においてセルロース繊維で強化することにより、成形体の強度及び剛性向上という効果がより顕著に発揮される。また、ポリオレフィン樹脂やポリアミド樹脂は、分子量のコントロールが容易である、共重合体による多様な変性が可能である、合成方法が確立されている等の利点も有する。 In the present invention, the thermoplastic resin is preferably a polyolefin resin or a polyamide resin. While polyolefin resins and polyamide resins have the advantage of being light in weight with a small specific gravity, there is room for improvement in the strength and rigidity of the molded body. Therefore, by strengthening with cellulose fibers in the present invention, the strength and rigidity of the molded body The effect of improvement is exhibited more remarkably. In addition, polyolefin resins and polyamide resins also have advantages such as easy control of molecular weight, various modifications by the copolymer, and establishment of a synthesis method.
　ポリオレフィン樹脂としては、低密度ポリエチレン、高密度ポリエチレン、直鎖状低密度ポリエチレン、ポリプロピレン、環状ポリオレフィン等のオレフィン重合体及びその共重合体並びにそれらの変性物を挙げることができる。また、ポリオレフィン樹脂は、エチレンαオレフィン共重合体又はプロピレンαオレフィン共重合体のような、エチレン及び／またはプロピレンと、炭素数４以上のαオレフィンとの共重合体でもよい。ポリオレフィン樹脂の中でも、特にポリプロピレンが、軽量であり、耐熱性、耐薬品性、成形性に優れることから好ましい。ポリプロピレンとしては、単独重合体の他に、エチレン・プロピレンブロック共重合体、エチレン・プロピレンランダム共重合体、プロピレン・ブテン共重合体等が例示される。 Examples of the polyolefin resin include olefin polymers such as low density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, and cyclic polyolefin, copolymers thereof, and modified products thereof. The polyolefin resin may be a copolymer of ethylene and / or propylene and an α-olefin having 4 or more carbon atoms, such as an ethylene α-olefin copolymer or a propylene α-olefin copolymer. Among polyolefin resins, polypropylene is particularly preferable because it is lightweight and has excellent heat resistance, chemical resistance, and moldability. Examples of polypropylene include an ethylene / propylene block copolymer, an ethylene / propylene random copolymer, and a propylene / butene copolymer in addition to a homopolymer.
　熱可塑性樹脂は、セルロース繊維との密着性を向上させるために、無水マレイン酸が付加した酸変性ポリオレフィンや、無水マレイン酸とαオレフィンなどのオレフィンとの共重合体等の、酸基を有するポリオレフィンを含むことができる。 The thermoplastic resin is a polyolefin having an acid group, such as an acid-modified polyolefin to which maleic anhydride is added or a copolymer of maleic anhydride and an olefin such as an α-olefin in order to improve adhesion to cellulose fibers. Can be included.
　酸基を有するポリオレフィンの量は、熱可塑性樹脂全体に対して０．５～５０重量％であることが好適である。 The amount of the polyolefin having an acid group is preferably 0.5 to 50% by weight based on the whole thermoplastic resin.
　ポリアミド樹脂としては、ナイロン６、ナイロン６６、ナイロン１２、ナイロン６，６６共重合体、ナイロン６，１２共重合体、メタキシレンアジパミド・ナイロン６共重合体等のポリアミド系重合体やそれらの変性物を挙げることができる。ポリアミド樹脂の中でも、ナイロン６、ナイロン６６を用いることが好ましい。 As the polyamide resin, polyamide polymers such as nylon 6, nylon 66, nylon 12, nylon 6,66 copolymer, nylon 6,12 copolymer, metaxylene adipamide / nylon 6 copolymer, and the like Denatured products can be mentioned. Among polyamide resins, nylon 6 and nylon 66 are preferably used.
　本発明の繊維強化樹脂組成物における熱可塑性樹脂の含有量は、繊維強化樹脂組成物１００質量部に対して、６０～９９重量部であることが好ましい。熱可塑性樹脂の含有量が上記範囲であると、繊維強化樹脂組成物の優れた成形性を保ちつつ、繊維強化樹脂組成物から得られる成形体の強度を高くすることができる。熱可塑性樹脂の含有量は、好ましくは６５～９９重量部であり、より好ましくは７５～９０重量部である。 The content of the thermoplastic resin in the fiber reinforced resin composition of the present invention is preferably 60 to 99 parts by weight with respect to 100 parts by weight of the fiber reinforced resin composition. When the content of the thermoplastic resin is within the above range, the strength of the molded body obtained from the fiber reinforced resin composition can be increased while maintaining the excellent moldability of the fiber reinforced resin composition. The content of the thermoplastic resin is preferably 65 to 99 parts by weight, more preferably 75 to 90 parts by weight.
（セルロース繊維）
　本発明の繊維強化樹脂組成物において、セルロース繊維は熱可塑性樹脂中に分散し、成形体の強度及び剛性を高める。本発明において用いられるセルロース繊維とは、主成分としてセルロースを含む繊維である。 (Cellulose fiber)
In the fiber reinforced resin composition of the present invention, the cellulose fibers are dispersed in the thermoplastic resin to increase the strength and rigidity of the molded body. The cellulose fiber used in the present invention is a fiber containing cellulose as a main component.
　セルロース繊維源は、特に限定されず各種公知のものを使用できる。具体的には、木材、木材以外の植物（コットン、麻、竹、ケナフ、ヘンプ、海草等）；ホヤが産生する動物繊維；酢酸菌等の細菌が産生するバクテリアセルロース；古紙；レーヨン、ポリノジック、キュプラ、リヨセル、アセテート等の再生セルロース；等が挙げられる。セルロース繊維は、１種類又は２種類以上を組み合わせて用いることができる。 The cellulose fiber source is not particularly limited, and various known materials can be used. Specifically, wood, plants other than wood (cotton, hemp, bamboo, kenaf, hemp, seaweed, etc.); animal fibers produced by sea squirts; bacterial cellulose produced by bacteria such as acetic acid bacteria; waste paper; rayon, polynosic, And regenerated cellulose such as cupra, lyocell, and acetate. Cellulose fibers can be used alone or in combination of two or more.
　本発明に用いるセルロース繊維の形態に特に限定はなく、例えば、セルロースナノファイバー、ミクロフィブリル化セルロース、パルプであることができる。 The form of the cellulose fiber used in the present invention is not particularly limited, and examples thereof include cellulose nanofiber, microfibrillated cellulose, and pulp.
　パルプの例は、広葉樹（Ｌ材）や針葉樹（Ｎ材）を機械的に粉砕して、チップ状とし、リグニンやオイル成分を除いたクラフトパルプ（ＫＰ）である。ＫＰはコスト的にも有利である。一方、ＫＰはパルプ中にヘミセルロースを残すので、酸やアルカリで分解しやすく、また熱変性を受けて変色などを引き起こす。この問題を避けるために、αセルロース体に近い形のパルプを用いてもよい。このようなパルプの例は、木材系ではサルファイドパルプ（ＳＰ）又はあらかじめチップを塩酸で処理したのちクラフトパルプ化されたＤＫＰ、あるいは非木系のパルプである。非木系パルプの代表例である麻やコットンなどは、繊維長が長いために、樹脂と複合させる際に、繊維自体で絡む場合が多い。コットン系パルプの一種である、コットンリンターパルプは、木材パルプと似た繊維長を持つために扱いやすい。パルプは、解繊されていることが好適である。 An example of pulp is kraft pulp (KP) from which hardwood (L material) or coniferous tree (N material) is mechanically crushed into chips to remove lignin and oil components. KP is advantageous in terms of cost. On the other hand, KP leaves hemicellulose in the pulp, so it is easily decomposed by acid or alkali, and undergoes thermal denaturation to cause discoloration. In order to avoid this problem, a pulp having a shape close to an α-cellulose body may be used. Examples of such pulp are sulfide pulp (SP) in the wood system, DKP which has been processed into kraft pulp after treating chips with hydrochloric acid in advance, or non-wood pulp. Since hemp and cotton, which are representative examples of non-wood pulp, have a long fiber length, they are often entangled with the fiber itself when combined with a resin. Cotton linter pulp, a kind of cotton pulp, is easy to handle because it has a fiber length similar to wood pulp. The pulp is preferably defibrated.
　再生セルロースは繊維長の制御が容易であるという特徴がある。 Regenerated cellulose is characterized by easy fiber length control.
　セルロースナノファイバーとは、繊維径が３ｎｍから３５ｎｍ以下のセルロースを意味しており、ＴＥＭＰＯ系触媒で作製させるカルボン酸変性体のセルロースナノファイバーの径は３～６ｎｍとも言われている。ミクロフィブリル化セルロースとは、パルプ等のセルロース繊維を機械的に解繊したもので、マイクロからナノレベルまでのセルロース繊維を意味しており、このような材料もセルロース繊維として、本発明に利用できる。 The cellulose nanofiber means cellulose having a fiber diameter of 3 nm to 35 nm or less, and the diameter of the cellulose nanofiber of the carboxylic acid-modified product produced with a TEMPO-based catalyst is also said to be 3 to 6 nm. Microfibrillated cellulose is a cellulose fiber such as pulp that has been mechanically defibrated, which means cellulose fibers from micro to nano level, and such materials can also be used in the present invention as cellulose fibers. .
　樹脂中のセルロース繊維の平均繊維長には特段の限定はないが、例えば、セルロース繊維の平均繊維長は、０．２～２０ｍｍであることができる。セルロース繊維の平均繊維長が上記範囲であれば、繊維強化樹脂組成物から得られる成形体の強度及び剛性を十分に高くすることができる。好ましくは、セルロース繊維の平均繊維長は、０．２～３ｍｍであり、より好ましくは、０．８～２ｍｍである。セルロース繊維の繊維長は、セルロース繊維の原料、解繊処理の方法等を選択することにより、適宜調整することができる。 The average fiber length of the cellulose fibers in the resin is not particularly limited, but for example, the average fiber length of the cellulose fibers can be 0.2 to 20 mm. If the average fiber length of a cellulose fiber is the said range, the intensity | strength and rigidity of the molded object obtained from a fiber reinforced resin composition can be made high enough. Preferably, the average fiber length of the cellulose fibers is 0.2 to 3 mm, more preferably 0.8 to 2 mm. The fiber length of the cellulose fiber can be appropriately adjusted by selecting the raw material of the cellulose fiber, the method of defibrating treatment, and the like.
　樹脂中のセルロース繊維の平均繊維径に特段の限定はないが、例えば、セルロース繊維の平均繊維径は、１５ｎｍ～３０μｍであることができる。セルロース繊維の繊維径は、セルロース繊維の原料、解繊処理の方法等を選択することにより、適宜調整することができる。 The average fiber diameter of the cellulose fibers in the resin is not particularly limited, but for example, the average fiber diameter of the cellulose fibers can be 15 nm to 30 μm. The fiber diameter of the cellulose fiber can be appropriately adjusted by selecting the raw material of the cellulose fiber, the method of defibrating treatment, and the like.
　セルロース繊維の繊維長及び繊維径は、例えば、走査型電子顕微鏡（ＳＥＭ）、光学顕微鏡等によって測定することができる。 The fiber length and fiber diameter of the cellulose fiber can be measured by, for example, a scanning electron microscope (SEM), an optical microscope or the like.
　本発明の繊維強化樹脂組成物におけるセルロース繊維の含有量は、特に限定されないが、熱可塑性樹脂１００重量部に対して０．５～７５重量部とすることができる。セルロース繊維の含有量が上記範囲にあることで、樹脂組成物から成形される成形体の引張強度、曲げ強度、強度及び剛性、耐衝撃性等が向上しやすい。セルロース繊維の含有量は、より好ましくは１～５０重量部であり、さらに好ましくは１０～５０重量部である。 The content of the cellulose fiber in the fiber reinforced resin composition of the present invention is not particularly limited, but can be 0.5 to 75 parts by weight with respect to 100 parts by weight of the thermoplastic resin. When the content of the cellulose fiber is in the above range, the tensile strength, bending strength, strength and rigidity, impact resistance, and the like of the molded body molded from the resin composition are easily improved. The cellulose fiber content is more preferably 1 to 50 parts by weight, and even more preferably 10 to 50 parts by weight.
（水溶性の多糖類）
　本発明の繊維強化樹脂組成物において、水溶性の多糖類は、セルロース繊維の表面（例えば側面）上に被膜を形成する。 (Water-soluble polysaccharide)
In the fiber reinforced resin composition of the present invention, the water-soluble polysaccharide forms a film on the surface (for example, side surface) of the cellulose fiber.
　「多糖類」とは、単糖分子がグリコシド結合によって多数（例えば、１０以上）重合した糖のことである。単糖類及び２糖類では分子量（分子長）が小さくて得られない被覆・被膜効果が、分子量（分子長）の大きい多糖類によれば得られると考えられる。 “Polysaccharide” refers to a sugar obtained by polymerizing a large number (eg, 10 or more) of monosaccharide molecules by glycosidic bonds. It is considered that a coating / coating effect that cannot be obtained with a monosaccharide and a disaccharide due to a small molecular weight (molecular length) can be obtained with a polysaccharide with a large molecular weight (molecular length).
　「水溶性である」とは、固体１ｇを粉末とした後、水中に入れ、１００℃以下で５分ごとに強く３０秒間振り混ぜたときに、３０分以内に３０ｍＬ未満の水に溶解する性質をいう。多糖類が、水温が低い場合には溶解しなくとも、水を加温すれば溶解する場合は、加温することによって、セルロース繊維へ被膜を形成することができるため、そのような場合は本発明においては「水溶性である」とする。 “Water-soluble” means that 1 g of solid is powdered and then placed in water, and when it is shaken vigorously every 5 minutes at 100 ° C. or lower for 30 seconds, it dissolves in less than 30 mL of water within 30 minutes. Say. Even if the polysaccharide does not dissolve when the water temperature is low, if the water dissolves when the water is heated, a film can be formed on the cellulose fiber by heating. In the present invention, it is “water-soluble”.
　セルロース繊維への被膜の形成のし易さの観点から本発明において用いられる水溶性の多糖のＧＰＣに基づく重量平均分子量は、１０万以上が好ましく、より好ましくは２０万以上であり、特に上限はないが、４０万以下であることが好ましい。 The weight average molecular weight based on GPC of the water-soluble polysaccharide used in the present invention is preferably 100,000 or more, more preferably 200,000 or more from the viewpoint of easy formation of a film on cellulose fibers, and the upper limit is particularly high. Although it is not, it is preferable that it is 400,000 or less.
　水溶性の多糖類の種類は特に限定されないが、合成多糖、天然多糖及び天然物変成多糖のいずれも用いることができ、例えば、α－１，４－グルカン（アミロース、アミロペクチン、グリコーゲン）、α－１，６－グルカン（デキストラン）、β－１，６－グルカン（プスツラン）、β－１，３－グルカン（例えばカードラン、シゾフィラン等）、α－１，３－グルカン、β－１，２－グルカン、β－１，４－ガラクタン、β－１，４－マンナン、α－１，６－マンナン、β－１，２－フラクタン（イヌリン）、β－２，６－フラクタン（レバン）、β－１，４－キシラン、β－１，３－キシラン、プルラン、アガロース、アルギン酸等並びにこれらの塩及び誘導体を挙げることができる。また、アミロースを含有するデンプンを用いてもよい。また、デキストリン類を用いてもよい。水溶性の多糖類は、１種類又は２種類以上を組み合わせて用いることができる。なお、セルロースは水溶性ではないので、本発明における「水溶性の多糖」には含まれない。 The type of water-soluble polysaccharide is not particularly limited, and any of synthetic polysaccharides, natural polysaccharides, and natural product modified polysaccharides can be used. For example, α-1,4-glucan (amylose, amylopectin, glycogen), α- 1,6-glucan (dextran), β-1,6-glucan (pustulan), β-1,3-glucan (eg curdlan, schizophyllan, etc.), α-1,3-glucan, β-1,2- Glucan, β-1,4-galactan, β-1,4-mannan, α-1,6-mannan, β-1,2-fructan (inulin), β-2,6-fructan (levan), β- Mention may be made of 1,4-xylan, β-1,3-xylan, pullulan, agarose, alginic acid and the like and their salts and derivatives. Further, starch containing amylose may be used. Dextrins may also be used. One or a combination of two or more water-soluble polysaccharides can be used. In addition, since cellulose is not water-soluble, it is not included in the “water-soluble polysaccharide” in the present invention.
　上記した多糖類の中では、プルランが好ましい。プルランは、グルコースがα－１,４結合で３分子連なったマルトトリオースを構成単位とし、マルトトリオースがα－１，６結合を介して連結した構造を有する水溶性の化合物である。プルランは多糖類の中でも優れた被膜性、接着性を有するため、セルロース繊維に強固に密着した被膜を効率的に形成することができ、セルロース繊維同士の凝集を防止する効果がより高くなる。さらに、プルランは優れた潤滑性を有するため、セルロース繊維が熱可塑性樹脂中で均一に分散しやすくなる。また、多糖類の中でも比較的低粘性のニュートン流体であることから、熱可塑性樹脂とセルロース繊維とを混練する際に混練しやすいという利点を有する。 Among the polysaccharides described above, pullulan is preferable. Pullulan is a water-soluble compound having a structure in which maltotriose in which three molecules of glucose are linked by α-1,4 bonds is a structural unit and maltotriose is linked through α-1,6 bonds. Since pullulan has excellent coating properties and adhesiveness among polysaccharides, it can efficiently form a coating firmly adhered to cellulose fibers, and the effect of preventing aggregation of cellulose fibers becomes higher. Furthermore, since pullulan has excellent lubricity, the cellulose fibers are easily dispersed uniformly in the thermoplastic resin. Further, since it is a Newtonian fluid having a relatively low viscosity among the polysaccharides, it has an advantage of being easily kneaded when the thermoplastic resin and the cellulose fiber are kneaded.
　本発明に用いられるプルランとしては、入手方法や種類に特に制限はないが、ＧＰＣに基づく重量平均分子量が５０００～５０万のものが好ましく、重量平均分子量が５万～４０万のものがより好ましい。重量平均分子量が上記範囲のプルランを用いることにより、プルランの被膜によるセルロース繊維への被覆効果がより良好なものとなると考えられる。 The pullulan used in the present invention is not particularly limited in the obtaining method and type, but preferably has a weight average molecular weight based on GPC of 5,000 to 500,000, more preferably 50,000 to 400,000. . By using pullulan having a weight average molecular weight within the above range, it is considered that the effect of covering the cellulose fiber by the film of pullulan is improved.
　また、多糖類の中で、デキストリン類も好ましい。デキストリン類は、デンプンやグリコーゲンの加水分解で得ることができ、α-グルコースがα－１,４またはα－１，６グリコシド結合によって重合した分子構造を有する化合物である。デキストリン類には、デキストリン、マルトデキストリン、粉あめが含まれる。デキストリン類も優れた被膜性、接着性を有するため、セルロース繊維に強固に密着した被膜を効率的に形成することができ、セルロース繊維同士の凝集を防止する効果が高くなる。本発明に用いられるデキストリン類としては、入手方法や種類に特に制限はないが、デキストロース当量（ＤＥ）が１０以下のものが好ましく、３．０以下のものがより好ましい。また、ＧＰＣに基づく重量平均分子量が５０００～５０万のものが好ましく、重量平均分子量が５万～４０万のものがより好ましい。重量平均分子量が上記範囲のデキストリン類を用いることにより、デキストリン類の被膜によるセルロース繊維への被覆効果がより良好なものとなると考えられる。 Of the polysaccharides, dextrins are also preferable. Dextrins can be obtained by hydrolysis of starch or glycogen, and are compounds having a molecular structure in which α-glucose is polymerized by α-1,4 or α-1,6 glycosidic bonds. Dextrins include dextrin, maltodextrin, and powdered candy. Since dextrins also have excellent film properties and adhesiveness, a film firmly adhered to cellulose fibers can be efficiently formed, and the effect of preventing aggregation of cellulose fibers is enhanced. The dextrins used in the present invention are not particularly limited in the obtaining method and type, but those having a dextrose equivalent (DE) of 10 or less are preferred, and those having a dextrose equivalent of 3.0 or less are more preferred. Further, those having a weight average molecular weight based on GPC of 5,000 to 500,000 are preferred, and those having a weight average molecular weight of 50,000 to 400,000 are more preferred. By using dextrins having a weight average molecular weight within the above range, it is considered that the coating effect on the cellulose fibers by the coating of dextrins becomes better.
　本発明の繊維強化樹脂組成物における水溶性の多糖類の含有量は、特に限定されないが、セルロース繊維１００重量部に対して、０．１～３０重量部であることが好ましい。セルロース繊維に対する水溶性の多糖類の含有量が上記範囲にあることで、セルロース繊維に対して効率的に多糖類が被膜を形成することができる。水溶性の多糖類は、より好ましくはセルロース繊維１００重量部に対して０．２～１０重量部である。 The content of the water-soluble polysaccharide in the fiber-reinforced resin composition of the present invention is not particularly limited, but is preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of cellulose fibers. When the content of the water-soluble polysaccharide in the cellulose fiber is in the above range, the polysaccharide can efficiently form a film on the cellulose fiber. The water-soluble polysaccharide is more preferably 0.2 to 10 parts by weight with respect to 100 parts by weight of the cellulose fiber.
（その他の成分）
　本発明の繊維強化樹脂組成物には、必要に応じて、上述した熱可塑性樹脂、セルロース繊維、水溶性の多糖類以外の成分が含まれていてもよい。このような成分としては、熱可塑性樹脂組成物に通常用いられる各種の添加剤、例えば、酸化防止剤、光安定剤、紫外線吸収剤、中和剤、滑剤、ブロッキング防止剤、分散剤、流動性改良剤、離型剤、難燃剤、発泡剤、着色剤、充填剤、増粘剤、低粘剤、結晶核剤等の添加剤が挙げられる。これらの添加剤の繊維強化樹脂組成物の含有割合は、繊維強化樹脂組成物全体を１００重量部とした際に、３０重量部以下であることが好ましい。 (Other ingredients)
The fiber reinforced resin composition of the present invention may contain components other than the above-described thermoplastic resin, cellulose fiber, and water-soluble polysaccharide, if necessary. Examples of such components include various additives usually used in thermoplastic resin compositions, such as antioxidants, light stabilizers, ultraviolet absorbers, neutralizers, lubricants, antiblocking agents, dispersants, and fluidity. Examples thereof include additives such as an improving agent, a release agent, a flame retardant, a foaming agent, a colorant, a filler, a thickener, a low viscosity agent, and a crystal nucleating agent. The content ratio of the fiber reinforced resin composition of these additives is preferably 30 parts by weight or less when the entire fiber reinforced resin composition is 100 parts by weight.
　（作用）
　本発明の実施形態にかかる繊維強化樹脂組成物によれば、セルロース繊維を含むものの水溶性の多糖類を含まない繊維強化樹脂組成物に比べて、成形体の強度及び剛性が高くなる。その理由は明らかではないが以下が考えられる。 (Function)
According to the fiber reinforced resin composition concerning embodiment of this invention, the intensity | strength and rigidity of a molded object become high compared with the fiber reinforced resin composition which does not contain water-soluble polysaccharide although it contains a cellulose fiber. The reason is not clear, but the following can be considered.
　水溶性の多糖類は、セルロース繊維の表面に被膜を形成する。したがって、溶融した熱可塑性樹脂と、セルロース繊維とが混合される際に、多糖類の被膜によりセルロース繊維同士の再結合が抑制されてセルロース繊維同士の凝集が低減され、セルロース繊維が熱可塑性樹脂中で均一に分散しやすくなること、混合中にセルロース繊維が解繊されやすくなることが考えられる。 Water-soluble polysaccharide forms a film on the surface of cellulose fiber. Therefore, when the melted thermoplastic resin and the cellulose fiber are mixed, the polysaccharide coating suppresses recombination of the cellulose fibers and reduces the aggregation of the cellulose fibers, and the cellulose fibers are contained in the thermoplastic resin. It is conceivable that it is easy to disperse uniformly and the cellulose fibers are easily defibrated during mixing.
　また、水溶性の多糖類の被膜が熱可塑性樹脂とセルロース繊維との密着性を高め、これにより強度及び剛性が向上することも考えられる。 It is also conceivable that the water-soluble polysaccharide coating increases the adhesion between the thermoplastic resin and the cellulose fiber, thereby improving the strength and rigidity.
（繊維強化樹脂組成物の製造方法）
　本発明の繊維強化樹脂組成物の製造方法は、溶融した熱可塑性樹脂と、セルロース繊維と、水溶性の多糖類とを混練するステップを含む。本発明の方法によれば、複雑な反応の制御が不要であり、簡便かつ効率的に、上述の繊維強化樹脂組成物を製造することができる。 (Method for producing fiber-reinforced resin composition)
The method for producing a fiber-reinforced resin composition of the present invention includes a step of kneading a molten thermoplastic resin, cellulose fibers, and a water-soluble polysaccharide. According to the method of the present invention, complicated reaction control is unnecessary, and the above-described fiber-reinforced resin composition can be produced simply and efficiently.
　上記の混練は、一軸または二軸押出機、ロール、バンバリーミキサー、ニーダー、ブラベンダー等の種々の混錬機により行うことができる。混錬機に投入するセルロース繊維は、水分散体でも、乾燥体でもよい。 The above kneading can be performed by various kneaders such as a single or twin screw extruder, a roll, a Banbury mixer, a kneader, and a Brabender. The cellulose fiber to be charged into the kneader may be an aqueous dispersion or a dry body.
　溶融した熱可塑性樹脂とセルロース繊維とを混練する際の温度は、熱可塑性樹脂が溶解する温度であればよい。例えば、結晶性の熱可塑性樹脂の融点＋２０～５０℃、非晶性の熱可塑性樹脂のガラス転移温度＋１００～１２０℃とすることができる。 The temperature at which the molten thermoplastic resin and the cellulose fiber are kneaded may be any temperature at which the thermoplastic resin dissolves. For example, the melting point of the crystalline thermoplastic resin can be +20 to 50 ° C., and the glass transition temperature of the amorphous thermoplastic resin can be set to +100 to 120 ° C.
　セルロース繊維は、あらかじめ解繊されていることが好ましい。解繊処理の方法については、特に限定されず、例えば、グラインダー法、高圧ホモジナイザー法、水中対向衝法、リファイナー法、超音波ホモジナイザー法、二軸混練法等の物理的処理、ＴＥＭＰＯ酸化法、オゾン酸化法、酵素処理法等の化学的処理、及びこれらを組み合わせて行うことができる。 The cellulose fiber is preferably defibrated in advance. The method of defibrating treatment is not particularly limited, and examples thereof include physical treatment such as a grinder method, a high-pressure homogenizer method, an underwater counter impact method, a refiner method, an ultrasonic homogenizer method, a biaxial kneading method, a TEMPO oxidation method, and ozone. Chemical treatments such as an oxidation method and an enzyme treatment method, and combinations thereof can be performed.
　シート状のパルプを解繊する場合には、一般的には二通りの方法があって、その一つは乾式法である。乾式法では、パルプシートをハンマーミルなどで粉砕しながら、粉砕物をエアブローで回収すると、解繊された繊維を得ることができるが、強い衝撃で、セルロースの結晶化度が低下する他、繊維長が短くなるなどの障害が現れる場合がある。更に得られた解繊物は低密度の綿状となるので、混練機へ樹脂とともに投入する際には、特殊な装置が必要となる場合がある。 There are generally two methods for defibrating sheet-like pulp, one of which is the dry method. In the dry method, when the pulverized material is recovered by air blow while the pulp sheet is pulverized with a hammer mill or the like, the defibrated fiber can be obtained. Obstacles such as shortening the length may appear. Furthermore, since the obtained defibrated material becomes a low-density cotton, a special apparatus may be required when it is put into the kneader together with the resin.
　シート状のパルプの別の解繊方法は、湿式法である。通常、パルプは水との馴染みがよく、水中で弱い力で、例えば、通常の撹拌装置かパルパー（撹拌装置）により繊維状に解繊することができる。この状態から吸引濾過法、遠心分離法、ベルトプレス法などにより余剰水を除くと、解繊した含水状態のセルロース繊維（水分散体）が得られる。樹脂と混練する場合には、ベントなど残留水を除く機能を有した混練機が必要となるが、解繊時に結晶化度が低下せず、繊維長も保存できる。 Another method of defibrating sheet-like pulp is a wet method. Normally, pulp is well-familiar with water and can be fibrillated with a weak force in water, for example, with a normal stirring device or a pulper (stirring device). When excess water is removed from this state by a suction filtration method, a centrifugal separation method, a belt press method, or the like, a fibrillated cellulose fiber (water dispersion) is obtained. In the case of kneading with a resin, a kneader having a function of removing residual water such as a vent is required, but the crystallization degree is not lowered during defibration and the fiber length can be preserved.
　一般的に湿式解繊法で得られるセルロース繊維濃度は、ＫＰの場合は１５～３０重量％程度、コットンリンターの場合は２０～３５重量％程度、ミクロフィブリル化セルロースの場合は５～２０重量％程度、セルロースナノファイバーの場合は０．３～３重量％であることができる。 Generally, the cellulose fiber concentration obtained by wet defibration is about 15 to 30% by weight for KP, about 20 to 35% by weight for cotton linter, and 5 to 20% by weight for microfibrillated cellulose. In the case of cellulose nanofibers, it can be 0.3 to 3% by weight.
　セルロースナノファイバーやミクロフィブリル化セルロース等を乾燥させると、これらが強く相互作用をするため、一般的には乾燥させずに含水状態のまま、樹脂と混練することが好適である。 When cellulose nanofibers, microfibrillated cellulose and the like are dried, they strongly interact with each other. Therefore, it is generally preferable to knead them with the resin in a water-containing state without drying.
　溶融した熱可塑性樹脂とセルロース繊維とを混練する際に、あらかじめ、セルロース繊維の表面に水溶性の多糖類の被膜が形成されていることが好適である。このようにするには、例えば、混練機に投入する前に、セルロース繊維の表面を、水溶性の多糖類で被覆して膜を形成しておくことが好適である。 When the molten thermoplastic resin and the cellulose fiber are kneaded, it is preferable that a water-soluble polysaccharide film is formed on the surface of the cellulose fiber in advance. In order to do this, for example, it is preferable to form a film by coating the surface of the cellulose fiber with a water-soluble polysaccharide before putting it into the kneader.
　具体的には、セルロース繊維に水溶性の多糖類を含む水溶液Ａを接触させること、及び、セルロース繊維に接触した前記水溶液Ａを加熱、減圧等により乾燥させることにより、セルロース繊維、及び、セルロース繊維の表面を被覆する水溶性の多糖類膜を有する被覆繊維を得ることができる。水溶液Ａの乾燥は、加熱、減圧、自然乾燥等の公知の方法で実施できる。 Specifically, the cellulose fiber and the cellulose fiber are brought into contact with the cellulose fiber by bringing the aqueous solution A containing a water-soluble polysaccharide into contact with the cellulose fiber, and drying the aqueous solution A in contact with the cellulose fiber by heating, decompression, or the like. It is possible to obtain a coated fiber having a water-soluble polysaccharide film covering the surface. The aqueous solution A can be dried by a known method such as heating, reduced pressure, or natural drying.
　また、水溶性の多糖類によるセルロース繊維の被覆は、混練機内で行うこともできる。
　具体的には、混錬機内で、固体の熱可塑性樹脂、セルロース繊維、水溶性の多糖類、および、水の混合物Ｂを混練すれば良い。混練機内では、この混合物Ｂの混練により混合物Ｂが加熱され、混合物Ｂ中の水を水蒸気として系外に除去することができる。この場合、ベントを有する混練機を用いることが好適である。混合物Ｂから水が除去されると、セルロース繊維の表面に水溶性の多糖類の被膜が形成される。その後、更に、水の除去された混合物を混練すれば、熱可塑性樹脂が溶融して、溶融した熱可塑性樹脂と、多糖類の被膜を有するセルロース繊維とが混練されることになる。 Moreover, the coating of the cellulose fiber with the water-soluble polysaccharide can also be performed in a kneader.
Specifically, a mixture B of solid thermoplastic resin, cellulose fiber, water-soluble polysaccharide, and water may be kneaded in a kneader. In the kneader, the mixture B is heated by the kneading of the mixture B, and the water in the mixture B can be removed out of the system as water vapor. In this case, it is preferable to use a kneader having a vent. When water is removed from the mixture B, a water-soluble polysaccharide film is formed on the surface of the cellulose fiber. Thereafter, if the mixture from which water has been removed is further kneaded, the thermoplastic resin is melted, and the melted thermoplastic resin and cellulose fibers having a polysaccharide coating are kneaded.
　なお、セルロース繊維は乾燥体であっても５～９重量％の吸着水を含有している。したがって、混練機に液体の水を投入しない場合であっても、熱可塑性樹脂、セルロース繊維、及び、水溶性の多糖類を含む混合物が混練機内での剪断により加熱され、吸着水がセルロース繊維から脱離して遊離水を形成するため、混練機内で熱可塑性樹脂、セルロース繊維、水溶性の多糖類、及び、水の混合物を形成させることができる。したがって、液体の水を投入しなくても、上述の繊維強化樹脂組成物の製造は可能である。 Note that the cellulose fiber contains 5 to 9% by weight of adsorbed water even in a dry body. Therefore, even when liquid water is not added to the kneader, the mixture containing the thermoplastic resin, cellulose fiber, and water-soluble polysaccharide is heated by shearing in the kneader, and the adsorbed water is separated from the cellulose fiber. Since it is desorbed to form free water, a mixture of thermoplastic resin, cellulose fiber, water-soluble polysaccharide, and water can be formed in the kneader. Therefore, the above-mentioned fiber reinforced resin composition can be produced without adding liquid water.
　効率よくセルロース繊維の表面に水溶性の多糖類を被覆するためには、上記の水溶液Ａ、及び、混合物Ｂは、１重量部の前記水溶性の多糖類に対して、５～１００重量部の水を含むことが好適である。 In order to efficiently coat the water-soluble polysaccharide on the surface of the cellulose fiber, the aqueous solution A and the mixture B are 5 to 100 parts by weight with respect to 1 part by weight of the water-soluble polysaccharide. It is preferred to contain water.
（成形体）
　上述した、本発明の繊維強化樹脂組成物からは、成形体を製造することができる。成形方法としては、特に制限なく各種公知の方法を用いることができ、例えば、圧縮成形、射出成形、押出成形、押出ラミネート成形、回転成形、カレンダー成形、真空成形、ブロー成形等を挙げることができる。また、成形体の形状も特に制限されない。本発明の繊維強化樹脂組成物から得られる成形体は、十分な強度及び剛性を有する。 (Molded body)
A molded body can be produced from the above-described fiber-reinforced resin composition of the present invention. As the molding method, various known methods can be used without particular limitation, and examples thereof include compression molding, injection molding, extrusion molding, extrusion lamination molding, rotational molding, calendar molding, vacuum molding, blow molding and the like. . Further, the shape of the molded body is not particularly limited. The molded product obtained from the fiber-reinforced resin composition of the present invention has sufficient strength and rigidity.
（セルロース繊維１の水分散体の作製）
　２重量％のＮＢＫＰ（針葉樹を原料とする晒しクラフトパルプ）を含む水スラリーを用意した。これを、パルパー（撹拌装置）で機械的に解繊してセルロース繊維１の水分散体を得た。その後、遠心分離機で余剰水分を除去して濃縮し、最終的にセルロース繊維１の濃度が２５重量％であるセルロース繊維１の水分散体を作製した。セルロース繊維１の平均繊維長は２．８ｍｍ、平均繊維径は２５μｍであった。 (Preparation of aqueous dispersion of cellulose fiber 1)
A water slurry containing 2% by weight of NBKP (bleached kraft pulp made from softwood) was prepared. This was mechanically defibrated with a pulper (stirrer) to obtain an aqueous dispersion of cellulose fibers 1. Thereafter, excess water was removed by a centrifuge and concentrated to finally produce an aqueous dispersion of cellulose fibers 1 in which the concentration of cellulose fibers 1 was 25% by weight. The average fiber length of the cellulose fiber 1 was 2.8 mm, and the average fiber diameter was 25 μm.
（セルロース繊維２の作製）
　シート状のＮＢＫＰをハンマーミルで砕き、フラッフ状のセルロース繊維２を得た。セルロース繊維２の平均繊維長は１．８ｍｍ、平均繊維径は２５μｍ、水分含有量は７重量％であった。 (Production of cellulose fiber 2)
Sheet-like NBKP was crushed with a hammer mill, and fluffy cellulose fibers 2 were obtained. The average fiber length of the cellulose fiber 2 was 1.8 mm, the average fiber diameter was 25 μm, and the water content was 7% by weight.
（セルロース繊維３の作製）
　１００重量部のセルロース繊維２に対し、１．０重量％濃度のプルラン水溶液を１０００重量部噴霧し、これらをよく混合し、その後６０℃で乾燥させ、１００重量部のセルロース繊維を１０重量部のプルランでコーティングしたセルロース繊維３を作製した。 (Production of cellulose fiber 3)
1000 parts by weight of an aqueous pullulan solution having a concentration of 1.0% by weight is sprayed on 100 parts by weight of the cellulose fibers 2, these are mixed well, and then dried at 60 ° C. Cellulose fiber 3 coated with pullulan was produced.
（実施例１～６）
　実施例１～４では、セルロース繊維１の水分散体と、ポリプロピレン（ＢＣ０６Ｃ、日本ポリプロ製）、酸変性ポリプロピレン（Ｈ１０００Ｐ、東洋紡製）、および粉末プルラン（食品級グレード「プルラン」、林原製）を表１記載の量で配合し、ベント付二軸混練機に供給して、ベントから水蒸気を排出させつつ混練し、さらに、２３０℃でポリプロピレンを溶融しながら混練し、繊維強化樹脂組成物を作製した。得られた繊維強化樹脂組成物から、射出成形体を作製し、その曲げ弾性率を測定した。なお、表１中、「部」は「重量部」を意味する。
　実施例５では、１０重量％のプルラン水溶液を２０重量部配合して、水の量を多くする以外は実施例２と同様とした。
　実施例６では、１０重量％のプルラン水溶液を２重量部配合した。 (Examples 1 to 6)
In Examples 1 to 4, an aqueous dispersion of cellulose fiber 1, polypropylene (BC06C, manufactured by Nippon Polypro), acid-modified polypropylene (H1000P, manufactured by Toyobo), and powdered pullulan (food grade grade “Pullan”, manufactured by Hayashibara) Blended in the amounts shown in Table 1, supplied to a biaxial kneader with a vent, kneaded while discharging water vapor from the vent, and further kneaded while melting polypropylene at 230 ° C. to produce a fiber reinforced resin composition did. From the obtained fiber reinforced resin composition, an injection-molded article was prepared, and the flexural modulus was measured. In Table 1, “parts” means “parts by weight”.
Example 5 was the same as Example 2 except that 20 parts by weight of a 10% by weight pullulan aqueous solution was blended to increase the amount of water.
In Example 6, 2 parts by weight of a 10% by weight aqueous pullulan solution was blended.
（比較例１～４）
　プルランを添加しなかったこと以外は、実施例１～４と同様にして、表１記載の配合で繊維強化樹脂を作製した。 (Comparative Examples 1 to 4)
A fiber reinforced resin was prepared according to the formulation shown in Table 1 in the same manner as in Examples 1 to 4 except that pullulan was not added.
（実施例７～１１）
　実施例７では、セルロース繊維１の水分散体に代えて、フラッフ状の乾燥したセルロース繊維２を用いたこと以外は、実施例２と同様にして、表１記載の配合で繊維強化樹脂を作製した。なお、セルロース繊維２は液体の水を含まないが、吸着水を７重量％含む。
　実施例８～１０では、表１の配合で液体の水をさらに添加する以外は実施例７と同様とした。
　実施例１１では、１０重量％のプルラン水溶液を２０重量部配合する以外は実施例７と同様とした。 (Examples 7 to 11)
In Example 7, a fiber reinforced resin was prepared by the formulation shown in Table 1 in the same manner as in Example 2, except that a fluffy dried cellulose fiber 2 was used instead of the aqueous dispersion of cellulose fiber 1. did. The cellulose fiber 2 does not contain liquid water but contains 7% by weight of adsorbed water.
Examples 8 to 10 were the same as Example 7 except that liquid water was further added according to the formulation shown in Table 1.
Example 11 was the same as Example 7 except that 20 parts by weight of a 10% by weight aqueous pullulan solution was blended.
（比較例５）
　プルランを添加しなかったこと以外は、実施例７と同様にして、表１記載の配合で繊維強化樹脂を作製した。 (Comparative Example 5)
A fiber reinforced resin was prepared in the same manner as in Example 7 except that no pullulan was added.
（実施例１２）
　粉末プルラン及びセルロース繊維２の組み合わせに代えて、あらかじめプルランを被覆したセルロース繊維３を用いた以外は、実施例７と同様にして、表１記載の配合でセルロース繊維強化樹脂を作製した。なお、セルロース繊維２０部に対して、２部のプルランが被覆している。 (Example 12)
A cellulose fiber reinforced resin was prepared according to the formulation shown in Table 1 in the same manner as in Example 7 except that cellulose fiber 3 previously coated with pullulan was used instead of the combination of powdered pullulan and cellulose fiber 2. In addition, 2 parts of pullulan covers 20 parts of cellulose fibers.
（比較例６）
　粉末プルランに代えて、粉末トレハロースを１０重量部配合したこと以外は実施例１と同様にして、繊維強化樹脂を作製した。 (Comparative Example 6)
A fiber reinforced resin was produced in the same manner as in Example 1 except that 10 parts by weight of powdered trehalose was blended instead of the powdered pullulan.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　実施例１～６、比較例１～４では、湿式解繊処理により得たセルロース繊維１の水分散体を用いた。実施例１～４および比較例１～４の比較によれば、プルランの添加の有無にかかわらず、セルロース繊維の量が増えるにしたがって曲げ弾性率が向上する傾向が見られるが、セルロース繊維の量を一定とした場合、プルランを添加した各実施例ではプルランを添加しない各比較例と比較して、有意に曲げ弾性率が向上している。また、プルランを添加した系では、セルロース繊維の量が増えるにつれて樹脂の結晶化度が高くなることもわかる。
　また、実施例２および実施例５の比較から、セルロース繊維水分散体に粉体プルランを添加した場合と、セルロース繊維水分散体にプルラン水溶液を添加した場合とでは、結晶化度や曲げ弾性率に影響を与えないことがわかる。
　また、実施例５と実施例６とを比較すると、プルランの添加量が実施例６では実施例５の１０分の１の量であったが、樹脂の結晶化度、曲げ弾性率について同様の効果を示した。 In Examples 1 to 6 and Comparative Examples 1 to 4, an aqueous dispersion of cellulose fiber 1 obtained by wet defibrating treatment was used. According to the comparison between Examples 1 to 4 and Comparative Examples 1 to 4, the bending elastic modulus tended to improve as the amount of cellulose fiber increased regardless of whether or not pullulan was added. Is constant, the flexural modulus is significantly improved in each example with pullulan added as compared with each comparative example without pullulan added. It can also be seen that in the system to which pullulan is added, the degree of crystallinity of the resin increases as the amount of cellulose fibers increases.
In addition, from the comparison between Example 2 and Example 5, the crystallinity and the flexural modulus were obtained when the powdered pullulan was added to the cellulose fiber aqueous dispersion and when the aqueous pullulan solution was added to the cellulose fiber aqueous dispersion. It can be seen that it does not affect
Further, when Example 5 and Example 6 were compared, the amount of pullulan added was one-tenth that of Example 5 in Example 6, but the same was true for the crystallinity of the resin and the flexural modulus. Showed the effect.
　粉末プルランに代えて、粉末トレハロースを１０重量部配合した比較例６では、実施例１～４とは異なり、樹脂の結晶化度が高くなったり、曲げ弾性率が向上したりする効果は見られなかった。 In Comparative Example 6 in which 10 parts by weight of powdered trehalose was mixed in place of powdered pullulan, unlike Examples 1 to 4, the effects of increasing the crystallinity of the resin and improving the flexural modulus were observed. There wasn't.
　実施例７～１１、比較例５では、乾式解繊処理により得た乾燥したセルロース繊維２を用いた。乾燥したセルロース繊維２と、粉末形態のプルランとを添加し、液体の水を添加しなかった実施例７と、プルランも水も添加しなかった比較例５とを比べると、ポリプロピレンの結晶化度は同程度であったが、実施例７の成形体の曲げ弾性率の値の方がやや高かった。さらに、実施例７～１０を比較すると、同量のセルロース繊維、同量のプルランを用いた場合、液体の水の添加量が増えるにつれ、ポリプロピレンの結晶化度が上がり、さらに、成形体の曲げ弾性率が上昇した。
　実施例７のように、液体の水を添加しなかった場合でも、セルロース繊維が吸着水として水分を含有しているため、加熱の過程でセルロース繊維から脱離する水によってプルランはセルロース繊維の表面に被膜を形成することができるが、実施例８～１０のように、液体の水を添加した方が、被膜形成の効果は高まると考えられる。 In Examples 7 to 11 and Comparative Example 5, dried cellulose fiber 2 obtained by dry defibrating treatment was used. Comparing Example 7 in which dried cellulose fiber 2 and pullulan in powder form were added and liquid water was not added, and Comparative Example 5 in which neither pullulan nor water was added, the crystallinity of polypropylene The bending elastic modulus of the molded body of Example 7 was slightly higher. Further, when Examples 7 to 10 are compared, when the same amount of cellulose fiber and the same amount of pullulan are used, as the amount of liquid water added increases, the degree of crystallinity of polypropylene increases, and the bending of the molded body increases. Elastic modulus increased.
Even when liquid water is not added as in Example 7, the cellulose fibers contain moisture as adsorbed water, so that the pullulan is separated from the cellulose fibers by the process of heating. A film can be formed on the film, but it is considered that the effect of forming the film is enhanced by adding liquid water as in Examples 8 to 10.
　実施例１１では、プルランを水溶液の形態で添加した。同量の粉体プルランとほぼ同量の水とを添加した実施例９と比較して、実施例１１においてポリプロピレンの結晶化度と成形体の曲げ弾性率は有意に高くなった。上述のように湿式解繊セルロース繊維の実施例２と実施例５では差がなかったのに対して、乾式解繊セルロース繊維においてこのような差が表れる理由は明らかではないが、湿式解繊セルロース繊維とは異なり、乾式解繊セルロース繊維では初めから水溶液として添加するほうがより効果的であると考えられる。 In Example 11, pullulan was added in the form of an aqueous solution. Compared with Example 9 in which the same amount of powder pullulan and almost the same amount of water were added, in Example 11, the crystallinity of polypropylene and the flexural modulus of the molded product were significantly increased. While there was no difference between Example 2 and Example 5 of wet defibrated cellulose fibers as described above, the reason why such difference appears in dry defibrated cellulose fibers is not clear, but wet defibrated cellulose Unlike fibers, dry defibrated cellulose fibers are considered more effective when added as an aqueous solution from the beginning.
　実施例１２は、セルロース繊維２をプルランであらかじめ被覆したセルロース繊維３を混練に用いた実施例である。実施例１２は、実施例１０，１１と同様のポリプロピレンの結晶化度および成形体の曲げ弾性率が得られた。すなわち、プルランで予めコーティングしたセルロース繊維を用いることにより、混練時に水を添加しなくとも、成形体の曲げ弾性率を効果的に上げることができた。 Example 12 is an example in which cellulose fiber 3 in which cellulose fiber 2 was previously coated with pullulan was used for kneading. In Example 12, the same degree of polypropylene crystallinity and bending elastic modulus as in Examples 10 and 11 were obtained. That is, by using cellulose fibers pre-coated with pullulan, it was possible to effectively increase the flexural modulus of the molded body without adding water during kneading.
　本発明は、優れた強度及び剛性を有する成形体が得られる繊維強化樹脂組成物を提供し、種々の分野で利用可能である。 The present invention provides a fiber reinforced resin composition from which a molded article having excellent strength and rigidity can be obtained, and can be used in various fields.

Claims (15)

  1. 　熱可塑性樹脂と、セルロース繊維と、少なくとも一つの水溶性の多糖類とを含む、繊維強化樹脂組成物。 A fiber reinforced resin composition comprising a thermoplastic resin, cellulose fibers, and at least one water-soluble polysaccharide.
  2. 　前記多糖類は、プルラン及びデキストリン類から成る群から選択される少なくとも一つである、請求項１に記載の繊維強化樹脂組成物。 The fiber-reinforced resin composition according to claim 1, wherein the polysaccharide is at least one selected from the group consisting of pullulan and dextrins.
  3. 　前記多糖類はプルランである、請求項１又は２に記載の繊維強化樹脂組成物。 The fiber-reinforced resin composition according to claim 1 or 2, wherein the polysaccharide is pullulan.
  4. 　前記熱可塑性樹脂はポリオレフィン樹脂又はポリアミド樹脂である、請求項１～３のいずれか１項に記載の繊維強化樹脂組成物。 The fiber-reinforced resin composition according to any one of claims 1 to 3, wherein the thermoplastic resin is a polyolefin resin or a polyamide resin.
  5. 　前記水溶性の多糖類は、前記セルロース繊維の表面を被覆している、請求項１～４のいずれか１項に記載の繊維強化樹脂組成物。 The fiber-reinforced resin composition according to any one of claims 1 to 4, wherein the water-soluble polysaccharide covers the surface of the cellulose fiber.
  6. 　１００重量部のセルロース繊維に対して、０．１～３０重量部の水溶性の多糖類を含む、請求項１～５のいずれか１項に記載の繊維強化樹脂組成物。 The fiber-reinforced resin composition according to any one of claims 1 to 5, comprising 0.1 to 30 parts by weight of a water-soluble polysaccharide with respect to 100 parts by weight of cellulose fibers.
  7. 　溶融した熱可塑性樹脂と、セルロース繊維と、少なくとも一つの水溶性の多糖類とを混練するステップを含む、
    　請求項１～６のいずれか１項に記載の繊維強化樹脂組成物の製造方法。     Kneading a molten thermoplastic resin, cellulose fibers, and at least one water-soluble polysaccharide,
    The method for producing a fiber-reinforced resin composition according to any one of claims 1 to 6.
  8. 　前記混練するステップするステップに供される前記セルロース繊維の表面には、あらかじめ前記水溶性の多糖類が被覆されている、請求項７に記載の方法。 The method according to claim 7, wherein the surface of the cellulose fiber subjected to the kneading step is coated with the water-soluble polysaccharide in advance.
  9. 　前記混練するステップの前に、
    　前記熱可塑性樹脂、前記セルロース繊維、前記水溶性の多糖類、及び、水を含む混合物を加熱して前記混合物から水を除去するステップを含む、請求項８に記載の方法。     Before the kneading step,
    The method according to claim 8, comprising heating the mixture including the thermoplastic resin, the cellulose fiber, the water-soluble polysaccharide, and water to remove water from the mixture.
  10. 　前記混合物を加熱するステップ及び前記混練するステップを、混練機内で行う、請求項９に記載の方法。 The method according to claim 9, wherein the step of heating the mixture and the step of kneading are performed in a kneader.
  11. 　加熱前の前記混合物は、１重量部の前記水溶性の多糖類に対して、５～１００重量部の水を含む、請求項９又は１０に記載の方法。 The method according to claim 9 or 10, wherein the mixture before heating contains 5 to 100 parts by weight of water with respect to 1 part by weight of the water-soluble polysaccharide.
  12. 　セルロース繊維と、前記セルロース繊維の表面を被覆する少なくとも一つの水溶性の多糖類の膜と、を備える、被覆繊維。 A coated fiber comprising cellulose fiber and at least one water-soluble polysaccharide film covering the surface of the cellulose fiber.
  13. 　前記多糖類はプルランである、請求項１２に記載の被覆繊維。 The coated fiber according to claim 12, wherein the polysaccharide is pullulan.
  14. 　セルロース繊維を少なくとも一つの水溶性の多糖類で被覆するステップを含む、
    　請求項１２又は１３に記載の被覆繊維の製造方法。     Coating the cellulose fibers with at least one water-soluble polysaccharide,
    A method for producing a coated fiber according to claim 12 or 13.
  15. 　前記被覆するステップは、前記セルロース繊維に前記多糖類を含む水溶液を接触させること、及び、前記セルロース繊維に接触した前記水溶液を乾燥させることを含む、請求項１４に記載の方法。
          The method according to claim 14, wherein the coating step includes contacting the cellulose fiber with an aqueous solution containing the polysaccharide and drying the aqueous solution in contact with the cellulose fiber.
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