JP2023115611A - Fiber-reinforced resin master batch, resin composition, method for producing fiber-reinforced resin master batch, and method for producing resin composition - Google Patents

Abstract

To provide a fiber-reinforced resin master batch having high energy efficiency and high reinforcement effect, and a resin composition including the same.SOLUTION: A fiber-reinforced resin master batch for thermoplastic resin comprises at least pulp fiber and thermoplastic resin mixed together. The pulp fiber is enzyme-treated pulp fiber (A). The thermoplastic resin is a thermoplastic resin (B) that is modified with a hydrophilic functional group and has a melting point lower than or equal to a melting point of a thermoplastic resin (M) as a base material.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a fiber-reinforced resin masterbatch, a resin composition, a method for producing a fiber-reinforced resin masterbatch, and a method for producing a resin composition.

Fine fibrous cellulose obtained by finely disintegrating plant fibers includes microfibril cellulose and cellulose nanofibers, and is fine fibers with a fiber diameter of about 1 nm to several tens of μm. Fine fibrous cellulose is lightweight, has high strength and high elastic modulus, and has a low coefficient of linear thermal expansion, and is therefore suitably used as a reinforcing material for resin compositions.

However, while the pulp fibers, which are the raw materials of the fine fibrous cellulose, are hydrophilic, the resin is hydrophobic. There was a problem that it was difficult to defibrate. On the other hand, a method of mixing and kneading with a resin after defibrating into fine fibrous cellulose has been adopted.

In Patent Document 1, after beating and enzymatic treatment of pulp fibers, cellulose nanofibers are obtained by fibrillating with a water stream, and a dispersion of the cellulose nanofibers is dried and then kneaded with a thermoplastic resin to form a thermoplastic resin composition. getting things The thermoplastic resin composition obtained by this method is relatively inexpensive, does not cause problems such as thermal recycling and solvent treatment, and has high strength.

However, in the resin composition obtained by the method of Patent Document 1, a dispersion of cellulose nanofibers produced by fibrillation treatment with a high-pressure water stream is mixed with polypropylene powder and dried while being stirred, and then kneaded with a thermoplastic resin. Therefore, the cellulose nanofibers, which have a high degree of miniaturization, agglomerate during drying due to the size of the specific surface area, causing a problem in dispersibility, and the reinforcing effect was not sufficient. In addition, since the fibrillation treatment is carried out using high-pressure water jets, the solid content concentration during production of cellulose nanofibers is low, so there is the problem that a large amount of energy is required for drying.

JP 2017-19976 A

An object of the present invention is to provide a fiber-reinforced resin masterbatch having a small drying load, excellent energy efficiency, and a high reinforcing effect, and a resin composition using the same. Another object of the present invention is to provide a method for producing this fiber-reinforced resin masterbatch and a method for producing a resin composition.

The present invention provides the following.
[1] A fiber-reinforced resin masterbatch in which at least pulp fibers and a thermoplastic resin are kneaded,
The pulp fibers are enzyme-treated pulp fibers (A),
The thermoplastic resin is a thermoplastic resin (B) modified with a hydrophilic functional group and having a melting point equal to or lower than the melting point of the thermoplastic resin (M) serving as the base material,
Fiber reinforced resin masterbatch for thermoplastic resins.
[2] A thermoplastic resin composition obtained by kneading the fiber-reinforced resin masterbatch according to [1] and a thermoplastic resin (M).
[3] (i) a step of treating the pulp fiber with an enzyme, and (ii) the enzyme-treated pulp fiber (A) and a thermoplastic thermoplastic modified with a hydrophilic functional group and having a melting point as a base material a step of drying and stirring a thermoplastic resin (B) having a melting point of resin (M) or lower to obtain a mixture; A method for producing a fiber-reinforced resin masterbatch for thermoplastic resin, comprising a step of kneading at a set temperature equal to or lower than the decomposition temperature.
[4] A method for producing a thermoplastic resin composition, comprising a step of kneading a fiber-reinforced resin masterbatch produced by the production method according to [3] above and the thermoplastic resin (M).

According to the present invention, dispersibility of the fibers in the resin is improved by performing defibration of the enzyme-treated pulp fibers and kneading with the resin at the same time, and a thermoplastic resin composition having excellent elongation at break can be obtained. In addition, since the number of mechanical processing steps can be reduced, it is possible to provide a method for producing a resin composition that does not require energy and has a small environmental impact.

(Pulp fiber (A))
Pulp as a raw material for the enzyme-treated pulp fiber (A) used in the present invention can be obtained by pulping a pulp raw material. The pulp raw material may be either wood or non-wood. Wood raw materials used for producing wood pulp include softwoods, hardwoods, and the like. Non-wood raw materials used to produce non-wood pulp include cotton, hemp, sisal, Manila hemp, flax, straw, bamboo, bagasse, kenaf, and the like. The pulp raw material (wood raw material, non-wood raw material) may be unbleached (before bleaching) or bleached (after bleaching).

The method of pulping the wood raw material is not particularly limited, and an example is a pulping method commonly used in the paper industry. Wood pulp can be classified according to the pulping method, for example, chemical pulp cooked by methods such as Kraft method, sulfite method, soda method, polysulfide method; ); semi-chemical pulp obtained by mechanical pulping after pretreatment with chemicals; waste paper pulp; deinked pulp, and the like.

In addition, the enzyme-treated pulp fiber (A) has a lignin content of 1% by mass or more and 30% by mass or less, preferably 3% by mass or more and 25% by mass or less, and more preferably 5% by mass or more and 20% by mass or less. preferable. If the lignin content is too much more than the above upper limit, the reinforcing effect will be reduced because the proportion of reinforcing fibers will be relatively low. Affinity is lowered and interfacial strength between fiber and resin is lowered. The lignin content can be adjusted by delignifying or bleaching the pulp raw material that is the raw material of the enzyme-treated pulp fiber (A). Moreover, the measurement of lignin content can be performed using the Clason method, for example.

The enzyme-treated pulp fibers (A) used in the present invention may be used in an undenatured state. It may be chemically modified.

(enzyme treatment)
By enzymatically treating pulp fibers, the enzyme-treated pulp fibers (A) used in the present invention can be obtained. The enzymes react with accessible sites on the pulp fiber surface, fibrillating the fiber surface and facilitating the disentanglement of the pulp fibers. It is believed that the dispersibility of the fibers in the resin is improved by facilitating the fibrillation of the pulp fibers, and as a result, a thermoplastic resin composition having excellent elongation at break can be obtained. At least one of a cellulase enzyme and a hemicellulase enzyme is preferably used as the enzyme.

(cellulase enzyme)
Cellulase enzymes are enzymes that can degrade cellulose. For example, endoglucanase that degrades cellulose from the inside of the molecule, exoglucanase that degrades cellulose from the end of the molecule, β- β-, which hydrolyzes glycosidic bonds and decomposes cellobiose into glucose. glucosidases or mixtures thereof. Cellulase treatment can improve the fibrillation properties of pulp fibers without excessively shortening the fiber length of the pulp. Although the mechanism is not clear, it is speculated that cellulase weakens hydrogen bonds between molecular chains, and fibrillation of fibers proceeds predominantly over scission of molecular chains. From this point of view, the cellulase is preferably endoglucanase, exoglucanase, β-glucosidase, or a mixture thereof.

The origin of the cellulase used in the present invention is not particularly limited, and it may be of various origins such as Trichoderma, Aspergillus, Irpex, Aeromonas, Clostridium, Bacillus, Pseudomonas, Penicillium, Humicola, or genetically modified cellulases. can be used singly or in admixture of two or more, and cellulases from filamentous fungi, basidiomycetes, bacteria, and the like can also be used. Also, the form of cellulase is not limited, and a commercially available cellulase preparation, a culture of the above bacteria, or a filtrate thereof may be used directly. Among them, cellulase having high cellulolytic activity such as cellulase derived from the genus Trichoderma or Aspergillus is preferable.

Cellulases are generally marketed as cellulase chemicals containing various chemicals such as multiple cellulases and buffering agents. In the present invention, the cellulase-based chemicals may be used, and examples thereof include "Cellulase T2" manufactured by HIPI, "Meicerase (registered trademark)" manufactured by Meiji Seika Pharma, "Harcobond (registered trademark)" manufactured by Riken Green Co., Ltd. Trademark) 8922”, “Novozyme (registered trademark) 188” “Cellcrust” “FiberCare R” manufactured by Novozyme, “Multifect CX10L, B, GCc, GC, pectinase (hemicellulase)” “Spezyme CP” manufactured by Genencor GC220” and the like.

(Hemicellulase enzyme)
A hemicellulase enzyme is an enzyme that causes the decomposition of hemicellulose in the presence of water. Examples of hemicellulase enzymes include xylanase, an enzyme that degrades xylan, mannase, an enzyme that degrades mannan, and arabanase, an enzyme that degrades araban.

Pectinase, which is an enzyme that decomposes pectin, can also be used as a hemicellulase enzyme. Microorganisms that produce hemicellulase enzymes often also produce cellulase enzymes.

Hemicellulose is a polysaccharide excluding pectins present between cellulose microfibrils in plant cell walls. Hemicelluloses are very diverse and differ between wood types and cell wall layers. Glucomannan is the main component in the secondary wall of coniferous trees, and 4-O-methylglucuronoxylan is the main component in the secondary wall of broadleaf trees. Therefore, it is preferred to use mannanase for obtaining fine fibrous cellulose from bleached softwood kraft pulp (NBKP), and xylanase for bleached hardwood kraft pulp (LBKP).

(Enzyme treatment conditions)
Enzymatic treatment can be carried out by contacting a slurry of pulp fibers with an enzyme. The medium in the slurry is preferably water. Although the concentration of pulp fibers in the slurry is not limited, it is preferably 0.01 to 10% by weight, more preferably 0.1 to 7.5% by weight. The amount of the enzyme added to the pulp fiber is preferably 0.1 to 3% by weight, more preferably 0.3 to 2.5% by weight, even more preferably 0.5 to 2% by weight. If the amount added is less than 0.1% by mass, the effect of the enzyme may decrease. On the other hand, if the amount added exceeds 3% by mass, cellulose or hemicellulose may be saccharified, and the yield of fine fibers may decrease. can't

(Timing of enzyme treatment)
The enzymatic treatment may be subjected to a mechanical treatment such as beating, which will be described later, before the treatment. It is preferred to carry out an enzymatic treatment.

The pH of the slurry may vary depending on the enzyme used, but is preferably pH 4-8 in the case of cellulase enzymes. From the viewpoint of cellulase activity, the temperature is 15° C. or higher, preferably 20° C. or higher, more preferably 25° C. or higher. The temperature conditions are not limited as long as cellulase is not deactivated, but the temperature is preferably less than 80°C, more preferably 65°C or less. In the case of hemicellulase enzymes, the pH is preferably 4-8. The temperature is 15° C. or higher, preferably 20° C. or higher, more preferably 25° C. or higher, from the viewpoint of hemicellulase activity. The temperature conditions are not particularly limited as long as the hemicellulase is not deactivated, but the temperature is preferably less than 80°C, more preferably 60°C or less.

(Deactivation treatment)
Although deactivation treatment is preferably performed after enzyme treatment, it does not matter whether deactivation treatment is performed or not because heat during resin kneading inactivates deactivation treatment. The deactivation treatment may be a treatment that changes the steric structure of the enzyme, and includes, for example, heat treatment, pH adjustment, salt concentration adjustment, addition of an oxidizing agent, addition of a solvent, etc. In the present invention, the above-mentioned It is preferable to deactivate the enzyme by a method of heating the slurry to 80° C. or higher, or a method of adding an alkaline substance such as sodium hydroxide so that the pH becomes about 12.

(freeness)
The pulp used for enzymatic treatment is not particularly limited in its Canadian standard freeness. From the viewpoint of the enzyme uniformly penetrating and reacting with the cellulose in the pulp fiber, when the freeness is lower than 600 mL by mechanical treatment, the specific surface area of the pulp increases and the reaction efficiency with the enzyme increases. can be expected. When the freeness exceeds 600 mL, the mechanical treatment step can be omitted, which is preferable from the viewpoint of contributing to cost reduction. Although the upper limit of freeness is not particularly limited, it is practically 800 mL or less. The Canadian standard freeness of the pulp fiber (A) can be measured according to JIS P 8121-2:2012.

(mechanical treatment)
The enzyme-treated pulp fibers (A) used in the present invention may be mechanically treated. In the present invention, the mechanical treatment generally means mixing fibers in a dispersion medium represented by water and fibrillating the mixture, and includes beating, dispersion, and the like. Apparatuses used for mechanical treatment are not limited, but examples include apparatus of types such as high-speed rotary, colloid mill, high pressure, roll mill, and ultrasonic, high pressure or ultrahigh pressure homogenizers, refiners, beaters, PFIs. Mills, kneaders, dispersers, high-speed disaggregators, topfiners, etc., centering on a rotating shaft, can be used to make wet pulp work with a metal or blade and pulp fibers, or by friction between pulp fibers. In the present invention, the mechanical treatment is preferably beating using a refiner or a kneader because the fibrillation of fibers can be efficiently advanced, and considering the drying load in the post-process, high-concentration treatment is possible. A beating treatment using a disc refiner or a conical refiner is more preferable.

The mechanical treatment is carried out using a mixture containing the enzyme-treated pulp fiber (A) and a dispersion medium. 15% by mass or more is more preferable, and 18% by mass or more is even more preferable. (Mechanical treatment at this concentration is also referred to as “high-concentration mechanical treatment”.) The dispersion medium is not limited, and an organic solvent or water can be used, but water is preferred. Solids concentration is the concentration of solids in the mixture subjected to mechanical treatment. By subjecting the pulp to mechanical treatment such as beating under conditions of a high solid content concentration of 10% by mass or more, merits such as improved treatment efficiency and improved handling properties can be obtained. As handling properties, for example, after high-concentration mechanical treatment, it can be transported as it is at high concentration without dilution, and the viscosity of the pulp dispersion that has undergone high-concentration mechanical treatment is not high and can be pumped. Another advantage is that the dispersion is less likely to stick to the inside of the storage container. Furthermore, when the drying step is performed after the high-concentration mechanical treatment, the amount of volatilized dispersion medium is small, and the drying efficiency is good.

If the solid content concentration during mechanical treatment exceeds 50% by mass, drying proceeds in the apparatus during the treatment and scorching of the material is likely to occur. A condition of mass % or less is more preferable.

In addition, the enzyme-treated pulp fiber (A) used in the present invention preferably has a moisture content of 1 to 90%, more preferably 10 to 85%, from the viewpoint of preventing aggregation in the resin and handling. Yes, more preferably 20 to 80%. The moisture content can be measured using, for example, a moisture meter that measures heat loss.

(Freeness after mechanical treatment)
The Canadian standard freeness after mechanical treatment of the enzyme-treated pulp fibers (A) used in the present invention is preferably 0 mL to 600 mL.

(Thermoplastic resin (B))
The thermoplastic resin (B) used in the present invention must be modified with a hydrophilic functional group, preferably acid-modified. The term "hydrophilicity" as used herein means having good affinity with water and the surface of cellulose. Hydrophilic functional groups include hydroxyl, carboxy, carbonyl, amino, amide, and sulfo groups. Examples of such thermoplastic resins (B1) include base-modified polyolefins and acid-modified polyolefins, and among them, maleic anhydride-modified polypropylene (MAPP) and maleic anhydride-modified polyethylene (MAPE) are exemplified.

The melting point of the thermoplastic resin (B) used in the present invention is not higher than the melting point of the thermoplastic resin (M) described below from the viewpoint of easy dispersibility. Here, for example, the melting point of maleic anhydride-modified polypropylene (MAPP) is 150°C, and the melting point of maleic anhydride-modified polyethylene (MAPE) is 120°C.

The thermoplastic resin (B) functions as a compatibilizing resin. The compatibilizing resin functions to uniformly mix the cellulose fibers with different hydrophobicity and the thermoplastic resin (M) to be described later and to enhance the adhesion. For example, in the case of maleic anhydride-modified polyolefin, factors that determine the characteristics of the compatibilizing resin include the amount of dicarboxylic acid added and the weight-average molecular weight of the polyolefin resin serving as the base material. A polyolefin resin having a large amount of dicarboxylic acid added increases compatibility with a hydrophilic polymer such as cellulose, but the molecular weight of the resin decreases during the addition process, resulting in a decrease in the strength of the molded product. As an optimum balance, the amount of dicarboxylic acid added is 20 to 100 mgKOH/g, more preferably 45 to 65 mgKOH/g. If the amount added is small, the number of points that interact with the hydroxyl groups of cellulose and the hydroxyl groups and modified functional groups contained in modified cellulose in the resin decreases. Further, when the addition amount is large, self-aggregation due to hydrogen bonding between carboxyl groups in the resin, or reduction in the molecular weight of the base material olefin resin due to excessive addition reaction, the strength as a reinforced resin is not achieved. The molecular weight of the polyolefin resin is preferably 35,000 to 250,000, more preferably 50,000 to 100,000. If the molecular weight is smaller than this range, the strength of the resin is lowered, and if it is larger than this range, the viscosity increases significantly when melted, resulting in poor workability during kneading and molding defects.

The blending amount of the thermoplastic resin (B) is preferably 10 to 70% by mass, more preferably 20 to 50% by mass, based on the mass (100% by mass) of the pulp fibers (A) excluding lignin. If the amount added exceeds 70% by mass, the amount exceeds the amount necessary for forming an interface between the cellulose and the resin.

The thermoplastic resin (B) may be used singly or as a mixed resin of two or more. In the case of use as a graft of one or more polymers and polyolefin, the polyolefin resin constituting the graft is not particularly limited. can be used.

(Fiber-reinforced resin masterbatch)
The fiber-reinforced resin masterbatch of the present invention includes at least enzyme-treated pulp fibers (A) and modified with hydrophilic functional groups, and has a melting point equal to or lower than the melting point of the thermoplastic resin (M) serving as the base material. It is a fiber-reinforced resin masterbatch in which the thermoplastic resin (B) is kneaded.

(Thermoplastic resin (M))
As the thermoplastic resin (M) used in the present invention, the following common thermoplastic resins having a melting temperature of 250° C. or less can be mentioned. The thermoplastic resin (M) may be used singly or as a mixture of two or more resins. The thermoplastic resin (M) may also be referred to as a diluent resin in the present invention.

General thermoplastic resins include polyolefin resin, polyamide resin, polyvinyl chloride, polystyrene, polyvinylidene chloride, fluororesin, (meth)acrylic resin, polyester, polylactic acid, copolymer resin of lactic acid and ester, poly Glycolic acid, acrylonitrile-butadiene-styrene copolymer (ABS resin), polyphenylene oxide, polyurethane, polyacetal, vinyl ether resin, polysulfone resin, cellulose resin (triacetylated cellulose, diacetylated cellulose, etc.), etc. can be used. can.

As the polyolefin resin, polyethylene, polypropylene (hereinafter also referred to as "PP"), ethylene-propylene copolymer, polyisobutylene, polyisoprene, polybutadiene, etc. can be used.

Polyamide resin (PA) is also expected to interact with hydroxyl groups of cellulose that have not been affected by urea, and can be preferably used. PA includes polyamide 6 (nylon 6, PA6), polyamide 11 (nylon 11, PA11), polyamide 12 (nylon 12, PA12), polyamide 66 (nylon 66, PA66), polyamide 46 (nylon 46, PA46), polyamide 610 (nylon 610, PA610), polyamide 612 (nylon 612, PA612), etc., aromatic diamines such as phenylenediamine, aromatic dicarboxylic acids such as terephthaloyl chloride and isophthaloyl chloride, or aromatic PAs composed of derivatives thereof etc. can be mentioned. From the viewpoint of high affinity with cellulose fibers and cellulose nanofibers, it is preferable to use aliphatic PA, more preferably PA6, PA11, and PA12, and particularly preferably PA6. Moreover, a polyamide resin may be used individually by 1 type, and may be used in mixture of 2 or more types of polyamide resins.

The resins exemplified above can be used not only as homopolymers but also as block copolymers containing less than half of resins having various known functions.

In the present invention, urea may be used as a low-molecular auxiliary agent for imparting a primary amine from the viewpoint of improving the strength of the resulting resin composition.

Urea has a thermal decomposition temperature of 135°C, and when it exceeds 135°C, it decomposes into ammonia and isocyanic acid. It is believed that the unmodified hydroxyl groups react with the generated isocyanic acid to promote the formation of urethane bonds, and it is speculated that the hydrophobicity increases compared to pulp fibers not subjected to urea treatment. Furthermore, by melt-kneading simultaneously with the thermoplastic resin (B) having an acid anhydride, the amino groups newly introduced to the surface of the pulp fiber by the urea treatment and the carboxylic acid of the thermoplastic resin (B) become hydrophilic mutually. It is believed that this action enables the formation of a stronger composite of the pulp fibers and the thermoplastic resin (B). As for the timing of adding urea, it is preferable to add it at the timing of step (ii) to be described later because of its thermal decomposition temperature.

The amount of urea is not particularly limited, but from the viewpoint of suppressing the decrease in strength due to the aggregation of fibers due to the excessive amount of urea, enzyme-treated pulp fibers excluding lignin (A) The ratio of the mass of urea to the mass of is preferably less than 0.8, more preferably 0.05 or more and less than 0.75, and still more preferably 0.1 or more and less than 0.7.

(Manufacturing method of fiber-reinforced resin masterbatch)
The method for producing the fiber-reinforced resin masterbatch of the present invention is not particularly limited, but for example, it can be produced by performing the following steps (i), (ii) and (iii).

(Step (i))
In step (i), the pulp fibers are treated with an enzyme.
In the step (i), the enzymatic treatment may be carried out by any apparatus as long as it is capable of stirring while maintaining the temperature of the dispersion within a certain range.

(Step (ii))
In step (ii), the enzyme-treated pulp fibers (A) and thermoplastic resin (B) are dried and stirred to obtain a mixture. Urea may be added in step (ii).

In the step (ii), a single-screw or multi-screw kneader (extruder) can be given as an apparatus for drying the raw material composition by heating it at a predetermined temperature while stirring (volatilizing the dispersion medium). From the viewpoint of versatility, it is preferable to use a twin-screw kneader. The set temperature of the barrel of the kneader when drying and stirring in step (ii) is not particularly limited, but the maximum temperature is preferably not higher than the decomposition temperature of the enzyme-treated pulp fibers (A). It is preferable that the minimum temperature be equal to or higher than the temperature at which the solvent can be volatilized. When urea is added at the same time, the temperature is preferably 135° C. or lower, which is lower than the decomposition temperature of urea.

In step (ii), the amount of the enzyme-treated pulp fibers (A) fed into the kneader is preferably 10 to 50% by mass, more preferably 20 to 40% by mass. If the solid content concentration of the cellulose fibers at the start of kneading is too lower than the above lower limit, the drying load increases, resulting in insufficient drying. A medium may be brought in, and the strength of the finally obtained resin composition may be lowered. If the solid content concentration of the cellulose fibers at the start of kneading is too higher than the above upper limit, the penetration of the dispersion medium into the cellulose fibers becomes poor, resulting in unevenness.

In step (ii), the dispersion medium is preferably removed until the resulting mixture has a solid content concentration of 90% by mass or more and 100% by mass or less, more preferably 95% by mass or more and 100% by mass or less.

(Step (iii))
In step (iii), the mixture obtained in step (ii) is melt-kneaded in a kneader that is the same as or different from the kneader used in step (ii) to obtain a fiber-reinforced masterbatch. Knead at a set temperature below the decomposition temperature of the enzyme-treated pulp fibers (A).

A single-screw or multi-screw kneader (extruder) is preferably used as an apparatus for performing kneading in step (iii) of the present invention. A twin-screw kneader (extruder) has a strong kneading force that promotes nano-ization of pulp, in addition to being able to melt-knead the enzyme-treated pulp fiber (A) and the thermoplastic resin (B). , a multi-screw kneader (extruder) such as a four-screw kneader (extruder), and a plurality of kneaders, rotors, and the like in the parts constituting the screw.

The set temperature of the barrel of the kneader when kneading the masterbatch in step (iii) is not particularly limited, but the maximum temperature is preferably not higher than the decomposition temperature of the enzyme-treated pulp fibers (A). The minimum temperature is preferably equal to or higher than the melting temperature of the thermoplastic resin (B). For example, when maleic anhydride-modified polypropylene is used as the thermoplastic resin (B), the maximum temperature is preferably 135° C. or higher and 200° C. or lower, more preferably 150° C. or higher and 180° C. or lower. The minimum temperature is not limited as long as stable operation is possible, but is preferably 60° C. or higher.

(Dilution kneading process)
In the dilution kneading step, the fiber reinforced resin masterbatch obtained in step (iii) and the thermoplastic resin (M) are kneaded. In other words, the masterbatch obtained in step (iii) and the diluent resin are kneaded.

When the thermoplastic resin (M) is added and melt-kneaded, the masterbatch and the thermoplastic resin (M) may be mixed without heating at room temperature and then melt-kneaded, or may be mixed with heating. It may be melt-kneaded.

As an apparatus for adding the thermoplastic resin (M) and performing melt-kneading, the same apparatus as used in the above step (iii) (masterbatch kneading step) can be used. Moreover, the heating setting temperature during melt-kneading is preferably about ±10° C., the minimum processing temperature recommended by the thermoplastic resin supplier for the thermoplastic resin (M). By setting the temperature within this temperature range, the pulp and resin can be uniformly mixed.

The resin composition produced by the production method of the present invention further includes, for example, surfactants; polysaccharides such as starches and alginic acid; natural proteins such as gelatin, glue and casein; tannins, zeolites, ceramics, metal powders, etc. colorants; plasticizers; fragrances; pigments; flow control agents; leveling agents; conductive agents; may The content of any additive may be appropriately contained within a range that does not impair the effects of the present invention.

According to the present invention, dispersibility of the fibers in the resin is improved by performing defibration of the enzyme-treated pulp fibers and kneading with the resin at the same time, and a thermoplastic resin composition having excellent elongation at break can be obtained. , it is possible to provide a method for producing a low-cost resin composition.

(Application)
Molding materials and moldings (molding materials and moldings) can be produced using the resin composition produced by the production method of the present invention. Examples of the shape of the molded body include various shaped bodies such as film-like, sheet-like, plate-like, pellet-like, powder-like and three-dimensional structures. As a molding method, die molding, injection molding, extrusion molding, blow molding, foam molding, etc. can be used.

The molded article (molded article) can be used not only in the field of fiber-reinforced plastics where matrix moldings (molded articles) containing cellulose fibers are used, but also in fields requiring thermoplasticity and mechanical strength (tensile strength, etc.).

Interior materials, exterior materials, structural materials, etc. for transportation equipment such as automobiles, trains, ships, and airplanes; housings, structural materials, internal parts, etc. for electrical appliances such as personal computers, televisions, telephones, and clocks; mobile communications such as mobile phones Housings, structural materials, internal parts, etc. of equipment; housings, structural materials, internal parts, etc. of portable music players, video players, printers, copiers, sporting goods; building materials; office equipment such as stationery, etc. It can be effectively used as a vessel, container, or the like.

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to these.

(Measurement of Canadian Standard Freeness (CSF))
The Canadian standard freeness of pulp fibers used in Examples and Comparative Examples was measured according to JIS P 8121-2:2012.

(Measurement of lignin content)
The lignin content of the pulp fibers used in Examples and Comparative Examples was measured based on the Clarson method commonly used as a quantitative method (Clason lignin). The lignin content can also be derived based on the kappa number measured according to JIS P 8211:2011. In general, the relationship between lignin content and kappa number varies depending on the type of pulp, so it is necessary to derive the correlation with the above-mentioned Clarson lignin. For example, in the case of softwood kraft pulp, lignin content = kappa number × 0 It can also be derived in .15. In addition, in this specification, when the lignin content is 10% by mass, the lignin content is 10.

(Measurement of tensile modulus)
150 g of pellet-shaped resin moldings obtained in Examples and Comparative Examples were put into a small molding machine ("MC15" manufactured by Xplore Instruments), and the heating cylinder temperature was 200 ° C. and the mold temperature was 40 ° C. A dumbbell-shaped test piece (type A12, JIS K 7139) was molded. The tensile modulus of the obtained test piece was measured using a precision universal testing machine ("Autograph AG-Xplus" manufactured by Shimadzu Corporation) at a test speed of 1 mm/min and an initial distance between gauge lines of 30 mm. A dumbbell-shaped test piece was molded in the same manner as described above using only the diluent resin (hPP), and the tensile modulus of the obtained test piece was measured in the same manner as described above. Table 1 shows the results of the ratio of the measured values of each sample at each time as the reinforcement rate.

(Measurement of bending strength)
150 g of pellet-shaped resin moldings obtained in Examples and Comparative Examples were put into a small molding machine ("MC15" manufactured by Xplore Instruments), and the temperature of the heating cylinder (cylinder) was 250 ° C., and the mold temperature was 40 ° C. A bar specimen was molded under the conditions (4 mm thickness, 80 mm parallel length). For the obtained test piece, using a precision universal testing machine (manufactured by Shimadzu Corporation "Autograph AG-Xplus", the test speed was 10 mm / min, the distance between fulcrums was 64 mm, and the elastic modulus, maximum stress, and breaking displacement were measured. The measured values are shown in Tables 1 and 2.

(Materials used for manufacturing masterbatch and resin composition)
(A) Pulp fiber treated with enzyme (degradation temperature: 299°C)
(B) Thermoplastic resin Maleic anhydride-modified polypropylene (MAPP): (Toyo Tac PMA-H1000P manufactured by Toyobo Co., Ltd.: amount of dicarboxylic acid added 57 mg KOH / g, melting point: 150 ° C.)
(M) Resin for dilution Homopolypropylene (hPP): (PP MA04A manufactured by Japan Polypropylene Corporation, melting point: 165°C)
・Cellulase (Wako Pure Chemical, Aspergillus origin)

(Production example 1)
(Production of pulp fiber 1)
Cellulase (Wako Jun drug) was added and stirred at 45° C. for 90 minutes to carry out cellulase treatment. Then, the dispersion was heated at 80° C. for 30 minutes for deactivation. The dispersion after the deactivation treatment is treated with a single disc refiner (manufactured by Kumagai Riki Kogyo Co., Ltd., plate blade width: 4 mm, groove width: 5 mm) until the Canadian standard freeness (CSF) reaches 0 mL, clearance: 0 Beating treatment was performed three times under conditions of .25 mm to obtain pulp fibers 1 having a moisture content of 20%.

(Production example 2)
(Production of Pulp Fiber 2)
Softwood unbleached kraft pulp (NUKP) with a solid content concentration of 18% by mass and a lignin content of 7.9% by mass is processed in a single disc refiner (manufactured by Kumagai Riki Kogyo Co., Ltd., Using a plate blade width of 4 mm and a groove width of 5 mm, the beating treatment was performed four times under conditions of a clearance of 0.25 mm to obtain pulp fibers 2 having a moisture content of 20%.

(Example 1)
(Manufacturing of masterbatch)
391 g of the solid content of the pulp fiber 1 produced in Production Example 1, 108 g of MAPP, and 252 g of urea (granular: manufactured by Mitsui Chemicals) are dried and stirred under conditions of 130° C. or less using a twin-screw extruder to obtain a mixture. got The entire amount of this mixture was kneaded at 180° C. or lower using a twin-screw extruder to obtain a masterbatch.

(Manufacture of resin composition)
41.8 g of the obtained masterbatch and 158.2 g of diluent resin (hPP) were mixed and kneaded under heating conditions of 180° C. or less using a twin-screw extruder. The melt-kneaded product was then pelletized using a pelletizer to obtain a pellet-like resin composition (molded article) containing pulp fiber 1, MAPP, a urea-derived compound, and a diluent resin (hPP).

(Comparative example 1)
A masterbatch and a resin composition (molded body) were produced in the same manner as in Example 1, except that pulp fiber 2 was used as pulp fiber 1.

As can be seen from Table 1, a fiber-reinforced resin masterbatch in which at least an enzyme-treated pulp fiber (A) and a thermoplastic resin (B) modified with a hydrophilic functional group are kneaded, and a diluent resin, heat The resin composition of Example 1 kneaded with the plastic resin (M) is the resin composition of Comparative Example 1 using pulp fibers not treated with enzymes instead of the pulp fibers (A) treated with enzymes. It had a larger breaking displacement and better breaking elongation than the others.

Claims (4)

A fiber-reinforced resin masterbatch in which at least pulp fibers and a thermoplastic resin are kneaded,
The pulp fibers are enzyme-treated pulp fibers (A),
The thermoplastic resin is a thermoplastic resin (B) modified with a hydrophilic functional group and having a melting point equal to or lower than the melting point of the thermoplastic resin (M) serving as the base material,
Fiber reinforced resin masterbatch for thermoplastic resins. A thermoplastic resin composition in which the fiber-reinforced resin masterbatch according to claim 1 and a thermoplastic resin (M) are kneaded. (i) a step of treating pulp fibers with an enzyme; and (ii) the enzyme-treated pulp fibers (A) and a thermoplastic resin (M ) drying and agitating the thermoplastic resin (B) having a melting point below the melting point of the pulp fiber (A) to obtain a mixture; A method for producing a fiber-reinforced resin masterbatch for thermoplastic resin, comprising a step of kneading at a set temperature of. A method for producing a thermoplastic resin composition, comprising kneading a fiber-reinforced resin masterbatch produced by the production method according to claim 3 and the thermoplastic resin (M).