Fibrous composite, method for producing same, and powder

Abstract

The purpose of the present invention is to provide with a configuration different from conventional configurations: a fibrous composite that can be handled without coexistence of cellulose fibers and moisture; a method for producing same; and powder. The fibrous composite is characterized in that: cellulose fibers and a copolymer having an acid-modification group are bound; the acid-modification group is an anhydrous carboxy group and / or a carboxy group derived from an anhydrous carboxy group; and the cellulose fibers and the copolymer are bound through an ester bond between a hydroxy group included in cellulose constituting the cellulose fibers and the acid-modification group. The powder is characterized by being formed from an assembly of the fibrous composite. The method for producing the fibrous composite is characterized by involving an esterification step in which the acid-modification group included in the copolymer is bound to a hydroxy group included in cellulose constituting the cellulosic fibers.

Description

Fibrous composite, its manufacturing method and powder

[0001] The present invention relates to a fibrous composite, a method for producing the same, and a powder thereof, and more particularly to a fibrous composite using cellulosic fibers, a method for producing the same, and a powder thereof.

[0002] In recent years, cellulose fibers have been used in aqueous applications for the purpose of controlling viscoelasticity, such as in thickeners. Meanwhile, in composite material applications, for example, cellulose fibers have been proven to be excellent reinforcing materials for resins for some time, but they have yet to be put to practical use. Thus, while cellulose fibers have been suggested to have excellent utility in composite material applications, they have not yet been put to practical use in many cases. One of the reasons for this is thought to be the strong hydrophilicity of cellulose fibers. Regarding this issue, the following patent documents 1 to 3 are known.

[0003] JP 2014-148629 A JP 2016-176052 A JP 2019-189792 A

[0004] While cellulose fibers are generally handled in an aqueous dispersion, it can be difficult to increase their solids concentration above 60% by mass. This solids concentration decreases as the degree of defibration of the cellulose fibers contained in the aqueous dispersion increases, and in products generally referred to as nanocellulose, the solids concentration does not reach 15% by mass. In other words, cellulose is handled in a state where it coexists with far more water than the target components. This is believed to be because cellulose, a polysaccharide, has many hydroxy groups derived from sugar chains, making it highly hydrophilic. For example, as mentioned above, blending with a resin is difficult if more water than the target components coexist. Even if blending is possible, removing the water requires significant energy costs. On the other hand, cellulose fibers have the property that, as the amount of water removed increases, the cellulose gradually aggregates and solidifies through hydrogen bonding. While this property is extremely useful in paper production, it is impossible to form a dispersion in the absence of water. Therefore, there is a problem that cellulose fibers cannot be dispersed in a non-hydrophilic environment, and cellulose fibers cannot be dispersed in a resin. As described above, cellulose fibers must be handled in the presence of water, and they aggregate when the dispersant is removed, making them difficult to handle. This has hindered their practical use in many applications and uses.

[0005] In this regard, the above-mentioned Patent Document 1 discloses a technology (e.g., [Claim 1]) for chemically modifying some of the hydroxyl groups in the cellulose constituting the nanocellulose with alkanoyl groups having an alicyclic hydrocarbon group, with the aim of providing novel modified nanocellulose and resin compositions containing the same (

[0011] ). The above-mentioned Patent Document 2 discloses a fiber-reinforced resin composition in which fibers with good dispersibility are suitably combined, and a method for producing the same (

[0007] ). The fiber-reinforced resin composition (e.g., [Claim 1]) contains (A) chemically modified cellulose nanofibers and (B) a thermoplastic resin, and the ratio R of the SP value of (A) to the SP value of (B) is 0.87 to 1.88, and the crystallinity of (A) is 42.7% or more. This disclosure mentions that the introduction of alkanoyl groups such as acetyl groups (i.e., the hydroxyl groups are chemically modified) blocks the hydroxyl groups of the cellulose molecules, thereby suppressing the hydrogen bonding strength of the cellulose molecules (

[0012] ). The above-mentioned Patent Document 3 discloses a modified cellulose nanofiber ([Claim 1], etc.) that has a cellulose nanofiber, a polycarboxylic acid bonded to the cellulose molecules, and a polyvalent metal salt of a fatty acid having 8 to 24 carbon atoms that is chelate-bonded to carboxy groups of the polycarboxylic acid other than the carboxy group bonded to the cellulose molecule, with the aim of providing a modified cellulose nanofiber that can be kneaded with a thermoplastic resin in a dry powder state and has good compatibility and dispersibility in the thermoplastic resin (

[0009] ).

[0006] The techniques described in Patent Documents 1 to 3 all address the above-mentioned problems by chemically modifying hydroxy groups derived from sugar chains. These techniques enable cellulose fibers to be handled in non-aqueous systems, thereby resolving the aforementioned resin formulation problems. However, for example, Patent Document 1 raises concerns about the need to use a special alicyclic compound as a chemical modifier, and Patent Document 2 raises concerns about the large amount of organic solvent used during production, requiring a total of 750 mL of organic solvent (Patent Document 1

[0445] ) for 5 g of plant fiber solids. Furthermore, the technique described in Patent Document 3 employs a chelate bond via a metal salt, which is less stable than chemical modification via covalent bonding, raising concerns about the long-term stability, hydrolysis resistance, and resistance to catalytic decomposition due to metal ions of products obtained using the modified cellulose. Thus, while various techniques are currently being investigated for chemical modification of cellulose, it remains unclear which techniques and solutions are appropriate and practical. Therefore, a greater variety of options are needed to provide more options for the future.

[0007] The present invention has been made in consideration of the above-mentioned situation, and aims to provide a fibrous composite that can handle cellulosic fibers in a non-aqueous system using a configuration different from conventional ones, a method for producing the same, and a powder thereof.

[0008] That is, the present invention includes the following: [1] A fibrous composite comprising a cellulosic fiber and a copolymer having an acid-modified group bonded together, wherein the acid-modified group is a carboxy anhydride group and / or a carboxy group derived from a carboxy anhydride group, and wherein the cellulosic fiber and the copolymer are bonded together by an ester bond between a hydroxy group of the cellulose constituting the cellulosic fiber and the acid-modified group. [2] The fibrous composite according to [1], wherein the copolymer has an ethylene-propylene copolymer, an ethylene-butene copolymer, an ethylene-octene copolymer, or a styrene-ethylene / butylene-styrene copolymer as a skeleton. [3] The fibrous composite according to [1] or [2], wherein the copolymer has structural units derived from at least two monomers differing in carbon number by two or more. [4] The fibrous composite according to any of [1] to [3], wherein the copolymer has five or more acid-modified groups. [5] The fibrous composite according to any of [1] to [4], wherein the fibrous composite is a modifier for olefin-based resins. [6] A powder characterized by being formed by assembling the fibrous composites according to any one of [1] to [5]. [7] A method for producing the fibrous composite according to any one of [1] to [5], comprising an esterification step of bonding the carboxy anhydride group of the copolymer to a hydroxy group of cellulose constituting the cellulosic fiber.

[0009] The fibrous composite of the present invention has a structure different from that of conventional ones, which allows the cellulosic fibers to be handled without being exposed to moisture. The method for producing a fibrous composite of the present invention allows the fibrous composite to be obtained. The powder of the present invention has a structure different from that of conventional ones, which allows the cellulosic fibers to be handled without being exposed to moisture.

[0010] 1 is a graph showing the correlation between flexural modulus and Charpy impact strength for Experimental Examples 1 to 2, 4, and 6 to 8. 2 is a graph showing the correlation between flexural modulus and Charpy impact strength for Experimental Examples 3 to 5, and 8.

[0011] The matters set forth herein are for illustrative purposes only and are intended to exemplify embodiments of the present invention, and are set forth for the purpose of providing what is believed to be the most effective and easily understandable explanation of the principles and conceptual features of the present invention. In this regard, it is not intended to show structural details of the present invention beyond the extent necessary for a fundamental understanding of the present invention, and the description, taken together with the drawings, will make clear to those skilled in the art how several forms of the present invention can be actually realized. In this specification, unless otherwise specified, the expression "XX to YY" means "XX or more and YY or less." Furthermore, "room temperature" means 25°C, and "room pressure" means 1013.25 hPa.

[0012] [1] Fibrous Composite The fibrous composite of the present invention is characterized in that it is formed by bonding a cellulosic fiber to a copolymer having an acid-modified group, the acid-modified group being a carboxy anhydride group and / or a carboxy group derived from a carboxy anhydride group, and the cellulosic fiber and the copolymer are bonded by an ester bond between a hydroxy group contained in the cellulose constituting the cellulosic fiber and the acid-modified group.

[0013] The above-mentioned "cellulosic fiber" means a fibrous material mainly composed of cellulose. In this specification, cellulosic fiber will be expressed as follows, as necessary. That is, cellulosic fiber, which is the raw material of a fibrous composite, will also be referred to as "aqueous cellulosic fiber." That is, aqueous cellulosic fiber is a cellulosic fiber that requires the coexistence of water to suppress aggregation without being bonded to a copolymer. Furthermore, cellulosic fiber incorporated into a fibrous composite and ester-bonded to a copolymer will also be referred to as "intra-composite cellulosic fiber." When the term is common to both aqueous cellulosic fiber and intra-composite cellulosic fiber, it will also be simply referred to as "cellulosic fiber."

[0014] Such cellulosic fibers typically have a maximum length of 1,000 μm or less, and can be 500 μm or less, 250 μm or less, or even 100 μm or less. The lower limit is not limited, and typically, a single cellulose fiber has a maximum length of 1 nm or more, 3 nm or more, 5 nm or more, or even 10 nm or more. These upper and lower limits can be appropriately combined. Thus, for example, the maximum length can be 1 nm to 1,000 μm, 3 nm to 500 μm, 5 nm to 250 μm, or 10 nm to 100 μm.

[0015] Specific examples include plant-derived fibers, pulp, cellulose microfibrils, cellulose nanofibers (hereinafter also referred to simply as "CNF"), lignocellulose (fibrous lignocellulose), etc. These may be used alone or in combination of two or more. Therefore, for example, CNF (fiber width 3 to 100 nm, aspect ratio 10 or more, length 100 μm or less) according to ISO / TS 20477:2017 is included.

[0016] The origin of the cellulosic fiber is not limited, and examples thereof include cellulosic fiber obtained from plants and cellulosic fiber produced by microorganisms (bacterial cellulose). These may be used alone or in combination of two or more. Among these, the cellulosic fiber obtained from plants may be one that has been primarily obtained from a plant, or may be one that has been re-obtained (secondarily obtained, or more multiple times obtained, etc.) from an article formed using the cellulosic fiber that has been primarily obtained.

[0017] The primary source of acquisition is not limited to, but may be, a tree, a plant, or other plants such as bamboo or algae. Examples of tree species include tall trees, shrubs, subshrubs, conifers, broad-leaved trees, evergreen trees, deciduous trees, and vines. The part of the tree is not limited to, and may be, for example, xylem, roots, leaves, or bark. On the other hand, the plant may be annual, biennial, perennial, upright, creeping, or creeping. The part of the plant is not limited to, and may be, for example, stems, roots, leaves, or other parts. These may be used alone or in combination of two or more. Examples of reacquisition sources include cloth, woven fabrics, knitted fabrics, and paper. These may be used alone or in combination of two or more.

[0018] The plant-derived fibers may be obtained by fiberizing a plant body in any manner, and examples thereof include plant-derived fibers fiberized by pulping, plant-derived fibers fiberized by retting, plant-derived fibers fiberized by microbial decomposition, plant-derived fibers fiberized by enzymatic decomposition, etc. These may be used alone or in combination of two or more.

[0019] Among the above, the plant-derived fibers (i.e., pulp) fiberized by pulping may be mechanically treated pulp (mechanical pulp (MP), groundwood pulp (GP), refiner ground pulp (RGP), thermomechanical pulp (TMP), etc.), chemically treated pulp (chemical pulp (CP), kraft pulp (KP), sulfite pulp (SP), soda pulp (AP), etc.), pulp treated to have properties of both of these (chemical ground pulp (CGP), semi-chemical pulp (SCP), etc.), or recycled pulp. Furthermore, it may be fiber pulp or dissolving pulp (DP). These may be used alone or in combination of two or more.

[0020] As mentioned above, the source of the pulp is not limited, and it may be wood pulp or non-wood pulp. Examples of wood pulp include softwood pulp (N pulp) and hardwood pulp (L pulp). These may be used alone or in combination of two or more. Examples of non-wood pulp include linter pulp, rag pulp, linen pulp, bagasse pulp, bamboo pulp, kenaf pulp, esparto pulp, hemp pulp, and straw pulp. These may be used alone or in combination of two or more.

[0021] Furthermore, there are no limitations on whether the pulp has been bleached. Examples include bleached hardwood kraft pulp (LBKP), unbleached hardwood kraft pulp (LUKP), bleached softwood kraft pulp (NBKP), unbleached softwood kraft pulp (NUKP), bleached hardwood sulfite pulp (LBSP), unbleached hardwood sulfite pulp (LUSP), bleached softwood sulfite pulp (NBSP), and unbleached softwood sulfite pulp (NUSP). These may be used alone or in combination of two or more. There are no limitations on whether the pulp has been beaten. These may be beaten pulp or unbeaten pulp. In the case of beaten pulp, it may be beaten pulp that has undergone a free beating treatment or a sticky beating treatment. These may be used alone or in combination of two or more. In the case of beaten pulp, the degree of beating and freeness (Canadian Freeness Standard [CFS]) are not limited.

[0022] Among the above, dissolving pulp (DP) can be selected from the viewpoints of odor reduction and heat resistance. Dissolving pulp has a high cellulose content, and therefore a lower content of lignin, which is thermally decomposed in a lower temperature heating environment, compared to non-dissolving pulp. Therefore, the use of dissolving pulp can reduce odor compared to when dissolving pulp is not used. Furthermore, better heat resistance can be obtained.

[0023] Here, the odor refers to an odor generated by the decomposition of components constituting cellulosic fibers. For example, in a molded body obtained from a resin for molding containing a fibrous composite, heating (heating to a temperature at which the resin can flow) is performed during the manufacturing process of the fibrous composite, the molding process of the resin for molding, etc., resulting in the decomposition of components constituting the cellulosic fibers, such as lignin. As a result, the resulting molded body may emit an odor. In contrast, when DP pulp is used as the cellulosic fiber, the amount of low-temperature decomposition components (such as lignin) contained in the DP pulp is small, or the DP pulp is substantially free of low-temperature decomposition components, so that no odor is generated even after the heating, or even if an odor is generated, the odor can be reduced.

[0024] Furthermore, excellent heat resistance can be exemplified by, for example, a reduced temperature dependence of mechanical strength. That is, as described above, in molded bodies obtained from resins for molded bodies containing a fibrous composite, lignin and the like are decomposed. Therefore, the mechanical strength of the resulting molded body may be strongly temperature-dependent. Specifically, the rate at which the flexural modulus decreases with increasing temperature can be cited as an example. In contrast, when DP pulp is used as the cellulosic fiber, the amount of low-temperature decomposition components (lignin, etc.) contained in the DP pulp is small or substantially absent, so the rate at which the flexural modulus decreases even after the above-mentioned heating can be reduced compared to the former.

[0025] As mentioned above, cellulosic fibers are fibrous materials primarily composed of cellulose. The percentage of cellulose contained in the cellulosic fibers is not limited, but can be, for example, 40% by mass or more, assuming that the entire cellulosic fiber is 100% by mass. When the cellulosic fibers contain 40% by mass or more of cellulose, the effects of cellulose can be effectively obtained. This percentage is preferably 50% by mass or more, and more preferably 60% by mass or more. This percentage may also be 100% by mass. The cellulose content in the cellulosic fibers is calculated from the alkali-decomposition-insoluble content. Specifically, the fibers are immersed in a 17.5% NaOH aqueous solution for two hours, followed by adding an equal volume of water to the NaOH aqueous solution and boiling for one hour. The dried residue (dried at 80°C or less) contained in the resulting liquid is used as the cellulose. Furthermore, if the measurement target contains lignin, the lignin is decomposed and removed by chlorine treatment, and then the cellulose content is measured. Specifically, the object to be measured is immersed in a solution of sodium chlorite and acetic acid mixed in a mass ratio of 5:1, heated at 80°C for 1 hour, and then filtered to obtain a residue, which is subjected to the same procedure a total of four times to measure the amount of cellulose contained in the residue from which lignin has been removed.

[0026] However, since the number of cellulosic fibers constituting a fibrous composite is large, and it is sufficient that a fibrous composite is formed as a result, there is no practical meaning in specifying the cellulose content of each cellulosic fiber. Similarly, when using cellulosic fibers derived from plants, the cellulose content varies depending on the source (type, part, etc.), and depending on the degree of purification, some fibers have a high cellulose content and others have a low cellulose content. Since these can be used in combination, it is sufficient that a fibrous composite is formed as a result, and there is no practical meaning in specifying the average value. Furthermore, since it is sufficient that a fibrous composite is formed as a result, the fibrous composite may or may not contain hemicellulose, lignin, and components derived therefrom.

[0027] Furthermore, the form of the cellulosic fiber is not limited other than being fibrous. Specifically, an aspect ratio of 4 or greater is preferred. An aspect ratio of 4 or greater facilitates maintaining the fibrous form of the fibrous composite. An aspect ratio of 5 or greater is more preferred, with 6 or greater being even more preferred. The aspect ratio is typically 10,000 or less. The aspect ratio can be determined by measuring the maximum and minimum lengths of the cellulosic fibers using an optical microscope or an electron microscope and calculating the ratio between them. However, since the number of cellulosic fibers constituting a fibrous composite is large, and the resulting fibrous composite is sufficient, specifying the aspect ratio of each individual cellulosic fiber is essentially meaningless. Similarly, when using plant-derived cellulosic fibers, the aspect ratio varies depending on the source (type, site, etc.), and some fibers have a high aspect ratio and some have a low aspect ratio depending on the processing process. Since these fibers can be mixed and used, specifying their average value is essentially meaningless as long as the resulting fibrous composite is sufficient.

[0028] The "copolymer" is a polymer having an acid-modified group and has structural units derived from two or more monomers. The acid-modified group is a group capable of functioning as an acid modified in the copolymer. In the present invention, it is at least one of a carboxy anhydride group and a carboxy group derived from a carboxy anhydride group. Of these, the former is a carboxy anhydride group having a closed ring structure. On the other hand, the latter is a carboxy group formed by ring-opening of a carboxy anhydride group. Therefore, the latter has a structure in which two carboxy groups are adjacent to each other (i.e., an open-ring structure). Hereinafter, the latter will also be referred to as a "dicarboxy group." As described above, the copolymer is ester-bonded to the cellulosic fiber in the fibrous composite. That is, the acid-modified group of the copolymer is ester-bonded to the hydroxy group of the cellulose. Therefore, since the acid-modified group of the copolymer is consumed by the ester bond in the fibrous composite, it is generally considered that the structure will consist of the ester bond and the carboxy group, which is the remainder of the carboxy anhydride group, present in the fibrous composite.

[0029] The copolymer has an acid-modified group, which can form an ester bond between the hydroxy group of cellulose and the acid-modified group. That is, by using a carboxy anhydride group and / or a dicarboxy group as the acid-modified group, high reactivity can be achieved within the copolymer, and high reactivity with the hydroxy group of cellulose can be obtained. Therefore, it can function as an effective reaction site within the polymer compound (copolymer), and the copolymer can be modified with respect to cellulose. Furthermore, since the polymer compound (copolymer) can be modified with respect to cellulose due to the small number of ester bonds, the hydroxy groups of cellulose can be widely inhibited, and the hydrophilicity of cellulose can be effectively inhibited.

[0030] A carboxy anhydride group originally contains two carboxy groups, which form a ring-closed carboxy anhydride group. On the other hand, a dicarboxy group is composed of two adjacent carboxy groups and is not ring-closed. That is, both a carboxy anhydride group and a dicarboxy group contain two carboxy groups, but at least one of these two carboxy groups is ester-linked to a hydroxy group in cellulose. That is, when a hydroxy group in cellulose is ester-linked to a carboxy anhydride group, only one of the two carboxy groups constituting the carboxy anhydride group is ester-linked, while the other carboxy group can remain as a carboxy group. Similarly, when a hydroxy group in cellulose is ester-linked to a dicarboxy group, only one of the two carboxy groups constituting the dicarboxy group is ester-linked, while the other carboxy group can remain as a carboxy group. Furthermore, in either case, the remaining carboxy group may also be ester-linked to another hydroxy group in cellulose.

[0031] Furthermore, by using a carboxy anhydride group and / or a dicarboxy group as the acid-modifying group, the copolymer can be modified into cellulosic fibers at a relatively low temperature. Therefore, the deterioration and decomposition of the cellulosic fibers during modification can be suppressed. That is, these acid-modifying groups are capable of reacting with water (H ２In the presence of carboxyanhydride (CO), the dicarboxyanhydride reacts with water to open the ring and exists as a dicarboxy group. However, since functional groups in the dicarboxy group state have lower reactivity than functional groups in the carboxyanhydride state, obtaining an ester bond requires a reaction temperature higher than the temperature at which the above-mentioned deterioration and decomposition occur. In contrast, high reactivity can be achieved by dehydrating and ring-closing the dicarboxyanhydride to form a carboxyanhydride group. That is, by increasing the probability of the presence of carboxyanhydride groups in the copolymer in advance, it is possible to obtain an ester bond at a reaction temperature lower than the temperature at which the above-mentioned deterioration and decomposition occur. Therefore, by ring-closing the carboxyanhydride group as represented by [—CO—O—OC—] and actually utilizing it as a literal carboxyanhydride group, the above-mentioned deterioration and decomposition can be avoided, thereby modifying the copolymer with respect to the cellulosic fiber.

[0032] As mentioned above, the anhydrous carboxyl group is a group that can be written as [—CO—O—OC—], and one molecule of H is formed from two carboxyl groups. ２ It is a group having a cyclic acid anhydride skeleton formed by dehydration of O. The carboxy anhydride group is also expressed as an acid anhydride group, a carboxylic acid anhydride group, a dicarboxylic acid anhydride group, etc. As described above, unless a ring-closure treatment is performed, it usually exists as a dicarboxy group. Whether the reactive group in the copolymer is a carboxy anhydride group or a dicarboxy group can be determined by infrared absorption spectroscopy. Specifically, when a carboxy anhydride group is present, a peak due to C=O of the carboxy anhydride group is detected at 1790 cm －１ and 1850 cm －１ On the other hand, when a dicarboxy group is present, a peak due to C═O is observed at 1700 to 1720 cm －１ When both of these are present, all of the above peaks are observed. The fibrous composite has a peak at 1790 cm due to the carboxyl anhydride group. －１ and the peak height of 1700 to 1720 cm due to the dicarboxy group －１ The peak height is equal to or equal to 1790 cm －１ This can be achieved by using a copolymer in which the peak height of

[0033] The acid-modified group may be derived from any monomer or compound. For example, it can be introduced into the copolymer using a structure derived from maleic acid, itaconic acid, succinic acid, glutaric acid, adipic acid, citraconic acid, tetrahydrophthalic acid, butenylsuccinic acid, and their acid anhydrides (i.e., maleic anhydride, itaconic anhydride, succinic anhydride, glutaric anhydride, adipic acid anhydride, citraconic anhydride, tetrahydrophthalic anhydride, butenylsuccinic anhydride, etc.). These may be used alone or in combination of two or more. Among these, structures derived from maleic acid and / or maleic anhydride are preferred. Note that a carboxyl anhydride group can form a dicarboxyl group by hydrolysis. Similarly, a dicarboxyl group can form a carboxyl anhydride group by dehydration condensation.

[0034] In the fibrous composite of the present invention, an acid-modified group is used as the reactive group. For example, instead of the carboxy anhydride group and the dicarboxy group, a carboxy group (—COOH, non-adjacent carboxy group), an epoxy group {—C ２ O (a three-membered ring structure consisting of two carbon atoms and one oxygen atom)}, an isocyanate group (—NCO), an oxazoline group (—C ３ H ４ NO) and the like can also be used. However, the carboxy group (—COOH) has the problem of lower reactivity compared to a ring-closed carboxy anhydride group. Furthermore, although epoxy groups, isocyanate groups, oxazoline groups, and the like have excellent reactivity, they are deactivated when they react with water in the system (for example, water coexisting with cellulose), and thereafter, there is a problem that they are unable to react with the hydroxy groups of cellulose. In this regard, even if a carboxy anhydride group reacts with water in the reaction system to become a dicarboxy group, it can be dehydrated again in the system and return to a carboxy anhydride group, so the carboxy anhydride group and dicarboxy group can ultimately be deactivated by reacting with the hydroxy groups of cellulose. For this reason, cellulose can be modified more efficiently than by using reactive groups other than acid-modified groups.

[0035] Furthermore, by using a copolymer as the main chain of a copolymer having an acid-modified group, the bulkiness of the copolymer having an acid-modified group can be obtained compared to using a homopolymer. Therefore, the hydrophilicity of cellulose can be more effectively inhibited. In this specification, "a copolymer having an acid-modified group" means that the main chain is a copolymer. Therefore, for example, modified polyethylene and modified polypropylene (maleic acid-modified PE and maleic acid-modified PP) have a main chain of polyethylene or polypropylene, and are not copolymers, so they are not included in the "copolymer" referred to in this application. On the other hand, for example, a modified ethylene-propylene copolymer is included in the "copolymer" referred to in this application because its main chain is a copolymer of ethylene and propylene. Similarly, for example, a modified ethylene-butene copolymer is included in the "copolymer" referred to in this application because its main chain is a copolymer of ethylene and butene.

[0036] Furthermore, by employing a copolymer as the main chain of a copolymer having an acid-modified group, the melting point of the copolymer can be kept lower than when a homopolymer is employed as the main chain. Therefore, the copolymer can react with cellulose at a lower temperature than when a homopolymer is employed as the main chain. Furthermore, by employing a copolymer as the main chain, the main chain can be made more flexible than when a homopolymer is employed as the main chain. Therefore, compared to when a homopolymer is employed as the main chain, more opportunities for the hydroxy groups of cellulose to react with the acid-modified groups of the copolymer can be provided. In other words, the reactivity between cellulose and the copolymer can be improved. From the same viewpoint, it is preferable that the acid-modified group be contained in a side chain of the copolymer, rather than being contained in the main chain of the copolymer.

[0037] Furthermore, by using a copolymer as the main chain of a copolymer having acid-modified groups, it is possible to obtain more elastomeric properties than by using a homopolymer. Therefore, when a fibrous composite is used as an additive component, the cellulosic fibers can be prevented from becoming fracture initiation points in the additive component. For example, when unmodified cellulosic fibers (e.g., those in which hydroxy groups derived from cellulose have been inhibited by other means) are added to an additive target (e.g., a resin), the additive target forms a matrix within which the unmodified cellulosic fibers are dispersed. In this case, the interface between the additive target and the unmodified cellulosic fibers is prone to dissociation due to the difference in their material properties, which can become a fracture initiation point. In contrast, in copolymer-modified cellulosic fibers (i.e., a fibrous composite), at least a portion of the cellulosic fibers is coated with the copolymer, and the copolymer is present at the interface between the additive target and the cellulosic fibers. Furthermore, the copolymer exerts elastic properties at the interface, thereby preventing the copolymer from becoming a fracture initiation point. Therefore, by using the copolymer as the main chain of the copolymer having an acid-modified group, it is possible to prevent cellulosic fibers from becoming the starting point of breakage in the added destination.

[0038] The structure of the copolymer skeleton (the main chain obtained by excluding the side chains from the copolymer) is not limited, and various structures can be adopted. Specific examples include olefin copolymers, styrene copolymers, etc. These may be used alone or in combination of two or more. Note that the olefin copolymer includes an olefin elastomer (olefin thermoplastic elastomer). Similarly, the styrene copolymer includes a styrene elastomer (styrene thermoplastic elastomer).

[0039] Examples of olefin copolymers include polymeric compounds obtained by copolymerizing two or more olefins as monomers. The copolymers may be random copolymers, block copolymers, copolymers of other types, hydrogenated copolymers thereof, or mixtures thereof.

[0040] Examples of the olefin include ethylene, propylene, and α-olefins having 4 to 8 carbon atoms. Examples of the α-olefins having 4 to 8 carbon atoms include butene (1-butene, etc.), pentene (3-methyl-1-butene, 1-pentene, etc.), hexene (3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, etc.), and octene (1-octene, etc.). These may be used alone or in combination of two or more.

[0041] Among these, copolymers of ethylene and other α-olefins are preferred as the olefin copolymers. That is, for example, copolymers of ethylene and an α-olefin having 3 to 8 carbon atoms, copolymers of propylene and an α-olefin having 4 to 8 carbon atoms, etc. These may be used alone or in combination of two or more.

[0042] Among the above, examples of copolymers of ethylene and an α-olefin having 3 to 8 carbon atoms include ethylene-propylene copolymer (EPR), ethylene-butene copolymer (EBR), ethylene-pentene copolymer, and ethylene-octene copolymer (EOR). Examples of copolymers of propylene and an α-olefin having 4 to 8 carbon atoms include propylene-butene copolymer (PBR), propylene-pentene copolymer, and propylene-octene copolymer (POR). These may be used alone or in combination of two or more. Among these, copolymers of ethylene and an α-olefin having 3 to 8 carbon atoms are preferred. That is, EPR, EBR, and EOR are preferred, and EBR and / or EOR are more preferred.

[0043] The styrene copolymer may be a polymer compound obtained by copolymerizing a styrene compound with another monomer, and may be a random copolymer, a block copolymer, a copolymer of another type, a hydrogenated product thereof, or a mixture thereof.

[0044] Examples of styrene-based compounds include styrene and its derivatives. These may be used alone or in combination of two or more. Among these, examples of styrene derivatives include alkylstyrenes such as α-methylstyrene, p-methylstyrene, and p-t-butylstyrene, p-methoxystyrene, and vinylnaphthalene. These may be used alone or in combination of two or more.

[0045] Examples of monomers other than styrene-based compounds include conjugated diene compounds and olefins. Among these, examples of conjugated diene compounds include butadiene, isoprene, piperylene, methylpentadiene, phenylbutadiene, 3,4-dimethyl-1,3-hexadiene, and 4,5-diethyl-1,3-octadiene. These may be used alone or in combination of two or more. On the other hand, the olefins described above may be used as the olefins.

[0046] Therefore, examples of styrene copolymers include styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), styrene-ethylene / butylene-styrene copolymer (SEBS, i.e., hydrogenated SBS copolymer), and styrene-ethylene / propylene-styrene copolymer (SEPS). These may be used alone or in combination of two or more. Of these, SEBS is preferred.

[0047] As described above, various options are available for the skeleton of the copolymer having an acid-modified group. However, from the viewpoint of obtaining higher elastomeric properties, it is preferable to adopt a skeleton having structural units derived from at least two monomers differing in the number of carbon atoms by two or more. That is, for example, in the case of an olefin-based copolymer, among EPR, EBR, EOR, PBR, POR, etc., EBR, EOR, and POR are preferred. In addition, in the case of a styrene-based copolymer, any of the above-mentioned copolymers is preferred. Furthermore, from the viewpoints of being more easily aligned with cellulose and less inhibiting its crystallinity, the skeleton of the copolymer having an acid-modified group is preferably linear rather than branched. A linear structure can more effectively inhibit the hydrophilicity of cellulose.

[0048] The copolymer may have one or more acid-modified groups, and the number is not limited, but because the copolymer is a polymer compound, having multiple acid-modified groups will result in higher reactivity than having only one acid-modified group. Furthermore, when actually forming ester bonds with cellulosic fibers, having ester bonds at multiple locations is preferable to having an ester bond at only one location, from the viewpoint of being able to more firmly modify the cellulose fibers with the copolymer.

[0049] As described above, the number of acid-modified groups contained in the copolymer (in the present invention, when the acid-modified group is a carboxy anhydride group, this refers to the number of carboxy anhydride groups; when the acid-modified group is a dicarboxy group, this refers to the number calculated as one set of two carboxy groups constituting the dicarboxy group) is not limited, but is preferably 2 or more, more preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more. On the other hand, the number of acid-modified groups does not need to be excessively large, and is usually 50 or less, preferably 30 or less, more preferably 20 or less, more preferably 12 or less, and can be 11 or less. These upper and lower limits can be appropriately combined. Thus, for example, the number can be 1 to 50, 2 to 30, 3 to 20, 4 to 12, or 5 to 11. Furthermore, the acid-modified group may be contained as a main portion within the backbone of the copolymer (for example, when maleic anhydride is used as a monomer), or may be contained in a graft side chain relative to the backbone of the copolymer, or both.

[0050] The copolymer may have no functional groups other than the acid-modified group, but may have other functional groups. In this case, the other functional groups may be carboxy groups (—COOH), epoxy groups (—C ２ O (a three-membered ring structure consisting of two carbon atoms and one oxygen atom)}, an oxazoline group (—C ３ H ４ These may be used alone or in combination of two or more.

[0051] The molecular weight of the copolymer having an acid-modified group is not limited, but the weight-average molecular weight can be 30,000 or more, 50,000 or more, or even 70,000 or more. By making the weight-average molecular weight of the copolymer 30,000 or more, sufficient bulkiness of the copolymer can be imparted to the cellulosic fiber, and the hydrophilicity of cellulose can be more effectively inhibited. On the other hand, the upper limit of the weight-average molecular weight is not limited, but is typically 1,000,000 or less, 500,000 or less, 300,000 or less, or 200,000 or less. The weight-average molecular weight of the copolymer may exceed 1,000,000, but an excessively large molecular weight makes the copolymer itself difficult to handle, so it is preferably 1,000,000 or less. These upper and lower limits can be combined as appropriate. Therefore, for example, the weight average molecular weight can be 30,000 to 1,000,000, 30,000 to 500,000, 50,000 to 300,000, or 70,000 to 200,000. The weight average molecular weight is measured by the GPC method (standard polystyrene equivalent).

[0052] Although the properties of the copolymer having an acid-modified group are not limited, for example, the MFR (230°C / 2.16 kg) of the copolymer having an acid-modified group can be 10 g / 10 min or less. By having the MFR of the copolymer be 10 g / 10 min or less, higher elastomer properties can be obtained. This MFR can be further set to 7 g / 10 min or less, or even 5 g / 10 min or less. The lower limit is not limited, but it can be set to 0.5 g / 10 min or more, or even 1.0 g / 10 min or more. The MFR (230°C / 2.16 kg) of the copolymer is a value based on ISO 1133. The density of the copolymer having an acid-modified group is 0.90 g / cm. ３ or less, and further 0.89 g / cm ３ The lower limit of the density is not limited, but it can be 0.85 g / cm ３These MFR and density can be adjusted by the molecular weight and modification amount of the copolymer. The density of the copolymer is a value based on ISO1183.

[0053] The cellulosic fiber and the copolymer having an acid-modified group may be bonded in any quantitative ratio, but the copolymer having an acid-modified group can be bonded in a range of 0.001 to 500 parts by weight per 100 parts by weight of the cellulosic fiber. Within this range, the modification of the copolymer having an acid-modified group allows the cellulosic fiber to be handled without coexistence with moisture. This quantitative ratio can be 0.005 parts by weight or more, 0.01 parts by weight or more, 0.5 parts by weight or more, 1 part by weight or more, 5 parts by weight or more, or 7 parts by weight or more. The upper limit is not limited, but can be 250 parts by weight or less, 150 parts by weight or less, 100 parts by weight or less, 80 parts by weight or less, or 50 parts by weight or less. These upper and lower limits can be combined as appropriate. Therefore, for example, it can be 0.005 to 250 parts by mass, 0.01 to 250 parts by mass, 0.5 to 150 parts by mass, 1 to 100 parts by mass, 5 to 80 parts by mass, or 7 to 50 parts by mass.

[0054] The uses of the fibrous composite are not limited, and it can be used, for example, as a raw material for a molded body, a modifier, a masterbatch, a support for additives, etc. The raw material for a molded body is the main component constituting the molded body. That is, since the fibrous composite contains a copolymer, the fibrous composite itself can be molded into a molded body. Examples of molded bodies include injection molded bodies, extrusion molded bodies (sheet extrusion molded bodies, profile extrusion molded bodies, etc.), T-die molded bodies, blow molded bodies, injection blow molded bodies, inflation molded bodies, hollow molded bodies, vacuum molded bodies, foam molded bodies, compression molded bodies, press molded bodies, stamping molded bodies, transfer molded bodies, transfer molded bodies, and insert molded bodies.

[0055] On the other hand, among the above, modifiers are components that can modify the properties of other materials when blended with them. Since fibrous composites contain cellulose fibers, they can be used as modifiers for fiber-reinforced resins, i.e., modifiers that improve the mechanical strength properties of molded articles obtained from the blended resin by blending them with a resin raw material for a molded article. Examples of mechanical strength properties include improved flexural modulus. Furthermore, examples of improved impact resistance include improving impact resistance to suppress the decrease in impact resistance that occurs as the flexural modulus increases. Furthermore, blending them with a resin raw material for a paint can modify the viscosity of the paint obtained from the blended resin for the paint. Examples of viscosity modifications include thickening, imparting or strengthening thixotropy, etc. Similarly, blending them with a resin raw material for an adhesive can modify the viscosity of the adhesive obtained by blending them. Examples of viscosity modifications include thickening, imparting or strengthening thixotropy, etc.

[0056] Furthermore, a masterbatch is similar to a modifier in that it is a component that can modify the properties of other materials by blending with them, but differs from a modifier in that it already contains the other materials. Furthermore, an additive carrier is a carrier used when adding an additive to other materials. The type of additive is not limited, but examples include flame retardants, flame retardant auxiliaries, fillers, colorants, antibacterial agents, antistatic agents, etc. These additives may be used alone or in combination of two or more.

[0057] Among the above, the fibrous composite can be suitably used as a modifier, masterbatch, carrier for additives, etc. The type of the other material is not limited, and examples thereof include resins (thermoplastic resins, curable resins), thermoplastic elastomers, rubbers, etc. These may be used alone or in combination of two or more. Among these, the fibrous composite can be suitably used when the other material is a thermoplastic resin and / or a thermoplastic elastomer. Examples of such other materials include a thermoplastic polyolefin resin and / or a thermoplastic polyolefin elastomer.

[0058] The type of olefin constituting the above-mentioned thermoplastic polyolefin resin and thermoplastic polyolefin elastomer is not limited, and examples thereof include ethylene, propylene, olefins having 4 carbon atoms (1-butene, etc.), olefins having 5 carbon atoms (3-methyl-1-butene, 1-pentene, etc.), olefins having 6 carbon atoms (3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, etc.), and olefins having 8 carbon atoms (1-octene, etc.). These may be used alone or in combination of two or more. Therefore, examples of polyolefins include polyethylene, polyethylene-based copolymers, polypropylene, polypropylene-based copolymers, polybutene, polybutene-based copolymers, etc. These polymers may be used alone or in combination of two or more. Furthermore, when two or more types are used, both pellets made of mixed resins and pellet mixtures are included.

[0059] Among the above, examples of polyethylene include ethylene homopolymers and copolymers of ethylene and olefins having 3 or more carbon atoms. Examples of the latter include ethylene-propylene copolymers, ethylene-butene copolymers, ethylene-hexene copolymers, and ethylene-octene copolymers. Furthermore, copolymers of ethylene and other olefins may be random copolymers or block copolymers. In addition, in copolymers of propylene and other olefins, 50% or more of the total number of constituent units are ethylene-derived constituent units.

[0060] As the polyethylene, plant-derived polyethylene (hereinafter simply referred to as "plant-derived PE") having a bio-based carbon content of 80% or more according to ISO 16620-2 can be used. This bio-based carbon content is the percentage of the total carbon content. １４This is a value calculated as the plant-derived carbon content (bio-based carbon content) based on the ratio of carbon to plant-derived carbon. When using plant-derived PE, a bio-based carbon content of 80% or more (or 100%) is preferred, and plant-derived PE with a bio-based carbon content of 85% or more, or even 90% or more can be used. In addition to ISO 16620-2, values ​​measured in accordance with the ASTM D6866 standard can also be used for the bio-based carbon content. Usually, the values ​​according to these standards are substantially the same.

[0061] Plant-derived PE has a methylene group (-CH ２ -) are linked together (methylene chain) as the main skeleton. The methylene chain is a structural unit derived from ethylene in particular. Plant-derived PE also includes ethylene homopolymers and copolymers of ethylene and other olefins. These may be used alone or in combination of two or more. When the plant-derived PE is a copolymer, non-ethylene-derived units (units derived from other olefins) preferably account for 50% or less (more preferably 30% or less, and even more preferably 10% or less) of the total number of structural units. This is because a lower proportion of non-ethylene-derived units can increase the bio-based carbon content. In other words, plant-derived PE that has a low proportion of non-ethylene-derived units (for example, 10% or less) and is essentially an ethylene homopolymer is preferred.

[0062] Examples of other olefins include olefins having 3 carbon atoms (propylene), olefins having 4 carbon atoms (1-butene, etc.), olefins having 5 carbon atoms (3-methyl-1-butene, 1-pentene, etc.), olefins having 6 carbon atoms (3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, etc.), olefins having 8 carbon atoms (1-octene, etc.), etc. These may be used alone or in combination of two or more.

[0063] The properties of plant-derived PE are not limited, but include a density of 0.942 g / cm ３Preferably, the plant-derived PE is a high-density polyethylene of 35 g / 10 min or less. The plant-derived PE preferably has an MFR (230°C / 2.16 kg) of 35 g / 10 min or less, and can be 20 g / 10 min or less, or even 15 g / 10 min or less. While the lower limit is not limited, from the viewpoint of ease of melt-kneading, it is preferably 2 g / 10 min or more, and can be 3 g / 10 min or more. The plant-derived PE has an MFR (230°C / 2.16 kg) measured in accordance with ISO 1133 or ASTM D1238. The values ​​according to these standards are usually substantially the same.

[0064] As mentioned above, the density of plant-derived PE is 0.942 g / cm ３ Preferably, the density is 0.950 g / cm or more. ３ The upper limit of the density is not limited, but it can be 0.954 g / cm ３ It is preferable that the density of the polyethylene is equal to or less than 1000 kJ / cm. The density of the polyethylene is a value measured in accordance with the standards of ISO 1183 or ASTM D792. The values ​​according to these standards are usually substantially the same. The compatibility of the above-mentioned MFR and density can be adjusted by the linearity, branching amount, molecular weight, etc. of the polyethylene.

[0065] Among the above-mentioned polypropylenes, examples include propylene homopolymers and copolymers of propylene with other olefins. Examples of the latter include propylene-ethylene copolymers. Examples include propylene-butene copolymers, propylene-hexene copolymers, and propylene-octene copolymers. Furthermore, copolymers of propylene with other olefins may be random copolymers or block copolymers. Among these, propylene-ethylene copolymers can be used from the viewpoint of their excellent elastomeric properties. Propylene-ethylene copolymers are block copolymer polypropylenes having ethylene blocks as a dispersed phase. That is, they are polypropylene resins in which homopolypropylene serves as a continuous phase and a dispersed phase containing polyethylene exists within this continuous phase. Such copolymer polypropylenes having ethylene blocks as a dispersed phase are also referred to as impact copolymers, polypropylene impact copolymers, heterophasic polypropylenes, heterophasic block polypropylenes, etc. Furthermore, in copolymers of propylene with other olefins, 50% or more of the total number of constituent units are derived from propylene.

[0066] The properties of the polyolefin as another material are not limited. For example, in the case of polypropylene, the density is 0.85 to 0.95 g / cm ３ (Furthermore, density 0.88 to 0.92 g / cm ３ ) can be used. Its MFR (230°C / 2.16 kg) can be, for example, 15 g / 10 min or more. When the MFR of the polypropylene is 15 g / 10 min or more (usually 100 g / 10 min or less), excellent impact resistance can be obtained. This MFR can be further increased to 20 g / 10 min or more, and even 25 g / 10 min or more. There is no upper limit, but from the viewpoint of ease of kneading, it can be set to 80 g / 10 min or less, and 50 g / 10 min or less. The MFR (230°C / 2.16 kg) of the polyolefin is measured in accordance with ISO 1133. The compatibility of MFR and density can be adjusted by the linearity, branching amount, molecular weight, etc. of the polyolefin.

[0067] [2] Powder The powder of the present invention is formed by assembling fibrous composites. The fibrous composites are as described above. As described above, the powder of the present invention contains cellulose fibers, but the coexistence of the ester-bonded copolymer allows it to be handled in a non-aqueous system. Therefore, it can be blended with resins that must be handled in a non-aqueous system. That is, it can be dispersed and contained within the resin. Therefore, a reinforced resin reinforced with the fibrous composite can be obtained. More specifically, for resins that have traditionally been reinforced using reinforcing agents such as glass fiber, whiskers, and fibrous fillers, the fibrous composite can be blended with the resin in place of these reinforcing agents or together with these conventional reinforcing agents.

[0068] Furthermore, resins (molded bodies) containing these reinforcing agents are difficult to reuse. That is, when conventional reinforcing agents are reused, they are destroyed during kneading, resulting in a decrease in aspect ratio and a decrease in reinforcing effect. In this regard, the powder of the present invention is formed from cellulose and a copolymer and is therefore flexible. Therefore, it is less likely to be destroyed during kneading during reuse, and the decrease in aspect ratio can be significantly suppressed. Therefore, reinforced resins using the powder of the present invention as a reinforcing agent can have excellent reusability.

[0069] Furthermore, when the cellulose-based materials and the like according to the techniques of Patent Documents 1 to 3 are blended with resin as a reinforcing agent, they can significantly improve rigidity, but a decrease in impact resistance is unavoidable. In this regard, when the powder of the present invention is used as a reinforcing agent, the decrease in impact resistance can be reduced compared to conventional reinforcing agents. In other words, compared to conventional products, molded articles with high impact resistance can be obtained while using a cellulose-based reinforcing agent.

[0070] [3] Method for producing a fibrous composite The method for producing a fibrous composite of the present invention is characterized by comprising an esterification step in which an acid-modified group contained in a copolymer having an acid-modified group is bonded to a hydroxy group contained in the cellulose constituting the cellulosic fiber.

[0071] The "esterification step" is a step of bonding an acid-modified group of a copolymer having an acid-modified group to a hydroxy group of the cellulose constituting the cellulosic fiber. The cellulosic fiber and the copolymer are as described above. The esterification step can be carried out by kneading the cellulosic fiber and the copolymer. However, as described above, the cellulosic fiber is dispersed in an aqueous system. Therefore, from the viewpoint of increasing the reaction efficiency, it is preferable to knead the non-aqueous cellulosic fiber and the copolymer rather than the aqueous cellulosic fiber and the copolymer.

[0072] Non-aqueous cellulosic fibers can be obtained by various conventional methods. For example, non-aqueous cellulosic fibers can be obtained by interposing a water-soluble nonionic compound between the cellulosic fibers. That is, cellulosic fibers can be modified so that they can be handled in a non-aqueous system. This modification can be achieved by interposing a water-soluble nonionic compound in place of the water interposed between the fibers of the aqueous cellulosic fibers. That is, the water-soluble nonionic compound can be dissolved in water coexisting with the aqueous cellulosic fibers, thereby forming a mixture containing dispersed aqueous cellulosic fibers, water, and the water-soluble nonionic compound. Then, by removing the water from this mixture, non-aqueous cellulosic fibers can be obtained in which the water-soluble nonionic compound is interposed between the fibers of the cellulosic fibers.

[0073] The water-soluble nonionic compound is a nonionic compound that is soluble in water. That is, it is a compound that can be dissolved in water without ionization. Therefore, by removing water from the mixture, the water-soluble nonionic compound remains in the gaps between the cellulosic fibers, preventing the aggregation of the cellulosic fibers. That is, the cellulosic fibers that have been made non-aqueous can be obtained in a non-aqueous form without chemically bonding (chemically reacting) the water-soluble nonionic compound to the cellulosic fibers or their constituents.

[0074] By utilizing this interpenetrating structure in which a water-soluble nonionic compound penetrates between aqueous cellulosic fibers, it is possible to obtain nonaqueous cellulosic fibers that can maintain a dispersed state without the coexistence of water, i.e., nonaqueous cellulosic fibers, from aqueous cellulosic fibers that cannot maintain a dispersed state without the coexistence of water, without chemical bonding. As a result, while aqueous cellulosic fibers must be handled as a liquid or fluid, nonaqueous cellulosic fibers can be handled as a powder. Furthermore, while aqueous cellulosic fibers require the coexistence of a large amount of water, nonaqueous cellulosic fibers do not, thereby achieving a significant weight reduction when handling the cellulosic fibers. Furthermore, removal of water eliminates the need for refrigeration, allowing storage at room temperature and normal pressure. In this way, nonaqueous conversion of aqueous cellulosic fibers (hereinafter simply referred to as the "nonaqueous conversion process") can significantly improve the handleability of the cellulosic fibers.

[0075] As mentioned above, the water-soluble nonionic compound forms a non-aqueous cellulosic fiber without bonding with the cellulosic fiber (no IR shift due to chemical bonding is observed). From this, it is believed that the cellulosic fiber and the water-soluble nonionic compound form a mutually penetrating structure (interpenetrating structure). This interpenetrating structure is further believed to be obtained by a coating structure in which the water-soluble nonionic compound covers the cellulosic fiber. This is derived from the fact that the non-aqueous cellulosic fiber exhibits excellent dispersibility in resin. That is, the non-aqueous cellulosic fiber can obtain excellent dispersibility in resin by having an interpenetrating structure and a coating structure with the water-soluble nonionic compound.

[0076] Examples of such water-soluble nonionic compounds include pyrrolidone compounds, formamide compounds, acetamide compounds, alcohol compounds, sulfoxides, and ketones. These may be used alone or in combination of two or more. Examples of pyrrolidone compounds include 2-pyrrolidone and 2-pyrrolidone derivatives such as N-methyl-2-pyrrolidone. These may be used alone or in combination of two or more. Examples of formamide compounds include formamide and formamide derivatives such as N,N-dimethylformamide. These may be used alone or in combination of two or more. Examples of acetamide compounds include acetamide and acetamide derivatives such as 2-chloroacetamide and N,N-dimethylacetamide, as well as polymers such as poly-N-vinylacetamide. These may be used alone or in combination of two or more. Examples of alcohol compounds include monohydric alcohols such as n-butanol, dihydric alcohols such as ethylene glycol, diethylene glycol, and propylene glycol, and polymers such as polyethylene glycol and polypropylene glycol. These may be used alone or in combination of two or more. Examples of sulfoxides include dimethyl sulfoxide, etc. These may be used alone or in combination of two or more. Examples of ketones include diethyl ketone, etc. These may be used alone or in combination of two or more.

[0077] The water-soluble nonionic compound may be a solid at room temperature and normal pressure, but is preferably a liquid. When the water-soluble nonionic compound is a liquid at room temperature and normal pressure, it has better solubility and dispersibility in water coexisting with aqueous cellulosic fibers than when it is a solid. That is, a small amount of the water-soluble nonionic compound can form the interpenetrating structure described above, and a small amount of the water-soluble nonionic compound can be used to powder the aqueous cellulosic fibers as non-aqueous cellulosic fibers. Among the above-mentioned water-soluble nonionic compounds, those that are solid at room temperature and normal pressure are acetamide, 2-chloroacetamide, poly-N-vinylacetamide, polyethylene glycol, and polypropylene glycol.

[0078] The degree of water solubility (solubility in water) of the water-soluble nonionic compound is not limited, but is preferably 0.05 g / 100 gH ２ It is preferable that the solubility is 0 or more. That is, it is preferable that 1 mass % or more of the water-soluble nonionic compound can be dissolved in an aqueous dispersion of aqueous cellulosic fiber having a solid content concentration of 5 mass %. A higher solubility is preferable from the viewpoint of dispersibility. That is, from the viewpoint of excellent dispersibility when dissolved in the aqueous dispersion, it is preferable that the solubility is higher, for example, 0.5 g / 100 g H ２ 0 or more, and 5g / 100gH ２ 0 or more, and 50g / 100gH ２ 0 or more, and 100g / 100gH ２ On the other hand, the upper limit of the solubility in water is not limited and is practically unlimited. That is, when the water-soluble nonionic compound is solid, for example, acetamide, the solubility is twice the amount of water present, that is, 200 g / 100 g H ２ If the water-soluble nonionic compound is a liquid, it may have a solubility that allows it to be miscible with water, such as N,N-dimethylacetamide.

[0079] Therefore, as mentioned above, from the viewpoint that higher solubility is preferable, among the water-soluble nonionic compounds exemplified above, liquids that are miscible with water are preferred. Therefore, 2-pyrrolidone, N-methyl-2-pyrrolidone, formamide, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, ethylene glycol, diethylene glycol, and propylene glycol are preferred. These may be used alone or in combination of two or more. Note that values ​​recorded in various databases (such as MERCK INDEX (https: / / merckindex.rsc.org / )) can be used for the solubility in water.

[0080] When the non-aqueous process includes a mixture-forming process (a process for forming a mixture of aqueous cellulosic fibers, water, and a water-soluble nonionic compound) and a water-removing process (a process for evaporating and removing water from the mixture), the mixture-forming process may be performed before the water-removing process, may be performed simultaneously with the water-removing process, or may be both. Simultaneous performance of the mixture-forming process and the water-removing process refers to a case in which the formation of the mixture and the removal of water from the mixture proceed simultaneously. For example, a case in which components constituting the mixture are added during the water-removing process may be exemplified. That is, a case in which a water-soluble nonionic compound is added to a mixture of aqueous cellulosic fibers and water while simultaneously removing water. Another example is a case in which water is added to a mixture of aqueous cellulosic fibers and water while simultaneously removing water. Examples of the latter include, for example, when dry pulp is used as a raw material for aqueous cellulosic fibers, a process in which water is added to more reliably dissociate the cellulosic fibers, or a process in which beating is performed while adding water to increase the degree of beating (a process for increasing the degree of defibration). By improving the dissociation state of the cellulosic fibers in this way, mutual penetration by the water-soluble nonionic compound can be more reliably achieved.

[0081] The mixture-forming step is a step of forming a mixture in which cellulosic fibers, a water-soluble nonionic compound, and water coexist. The method for forming the mixture is not limited as long as it can form a state in which cellulosic fibers, a water-soluble nonionic compound, and water coexist. For example, the mixture can be obtained by (1) mixing a mixture of aqueous cellulosic fibers and water with a water-soluble nonionic compound. Alternatively, the mixture can be obtained by (2) mixing cellulosic fibers, water, and a water-soluble nonionic compound. Furthermore, the mixture can be obtained by (3) mixing cellulosic fibers with a mixture of a water-soluble nonionic compound and water. Furthermore, in the case of (1) above, the water-soluble nonionic compound can be added to the coexisting materials while mixing, or a mixture of a water-soluble nonionic compound and water can be added to the coexisting materials while mixing. These materials may be used alone or in combination of two or more. When a mixture of aqueous cellulosic fiber and water is used to form the mixture, the ratio of aqueous cellulosic fiber to water in the mixture is not limited.

[0082] Any device may be used to form the mixture, and examples thereof include a mixer, kneader, extruder, kneader, and mixer (high-speed fluid mixer, paddle mixer, ribbon mixer, etc.). These may be used alone or in combination of two or more types. When two or more types are used, they may be operated continuously or batchwise (batchwise). Furthermore, the raw materials may be mixed all at once, or may be added and mixed in multiple batches (multi-stage blending). Furthermore, when these devices have a screw, they may be single-shaft, twin-shaft, or multi-shaft.

[0083] The proportion of each component in the mixture is not limited, but the components can be blended in the mixture so that the non-aqueous cellulosic fiber and the water-soluble nonionic compound are blended in the resulting non-aqueous cellulosic fiber. That is, the total of the cellulosic fiber and the water-soluble nonionic compound is taken as 100% by mass, and the proportion of the cellulosic fiber is taken as R Ｃ The ratio of the water-soluble nonionic compound is R Ｗ In terms of mass%, RＣ / R Ｗ >1 is preferable, and the lower limit thereof can be 1.1 or more, 1.3 or more, 1.5 or more, 2.0 or more, 3.0 or more, 5.0 or more, or 7.5 or more. On the other hand, this ratio (R Ｃ / R Ｗ The upper limit of R can be 10,000 or less, 1,000 or less, 500 or less, 100 or less, 50 or less, 25 or less, or 15 or less. These upper and lower limits can be appropriately combined. Therefore, for example, 1.0≦R Ｃ / R Ｗ ≦10000, and 1.1≦R Ｃ / R Ｗ ≦1000, and 1.1≦R Ｃ / R Ｗ ≦500, and 1.5≦R Ｃ / R Ｗ ≦100, and 2.0≦R Ｃ / R Ｗ ≦50, and 3.0≦R Ｃ / R Ｗ ≦25, and 5.0≦R Ｃ / R Ｗ ≦15, and 7.5≦R Ｃ / R Ｗ ≦15. However, for example, after removing water by evaporation, a step of removing the water-soluble nonionic compound can be provided so that the amount of the water-soluble nonionic compound is appropriate. When such a water-soluble nonionic compound removal step is provided, a large amount of the water-soluble nonionic compound can be blended regardless of the blending ratio.

[0084] The water removal step is a step of removing water from the mixture. Water removal may be performed by any method, and examples of the removal method include removal by evaporation (evaporative removal), removal by centrifugation (centrifugal removal), and removal by compression (compressive removal). These methods may be used alone or in combination of two or more. Among these, evaporation is preferred. When removing water by evaporation, by using a water-soluble nonionic compound having a boiling point higher than the boiling point of water, only water can be efficiently removed, and substantially the entire amount of the water-soluble nonionic compound blended in the mixture can be left in the resulting non-hydrated cellulosic fiber, thereby suppressing loss of the water-soluble nonionic compound.

[0085] The boiling point of the water-soluble nonionic compound is not limited, but when a water removal step by evaporation is performed, a water-soluble nonionic compound having a boiling point of more than 100° C. can be used. When the boiling point of the water-soluble nonionic compound is more than 100° C., the difference in boiling points between water and the water-soluble nonionic compound can be utilized to remove water from a mixture of aqueous cellulosic fiber, water, and the water-soluble nonionic compound by evaporation, thereby obtaining non-aqueous cellulosic fiber.

[0086] Furthermore, from the viewpoint of facilitating separation from water during evaporation, the boiling point difference with water can be made larger. That is, for example, the boiling point of the water-soluble nonionic compound is preferably 125°C or higher, preferably 150°C or higher, preferably 160°C or higher, preferably 170°C or higher, preferably 180°C or higher, and preferably 190°C or higher. On the other hand, although there is no upper limit to the boiling point of the water-soluble nonionic compound, when considering the case where it is blended with a resin as a modifier, it is preferable that it can be evaporated by heating during mixing (melting and kneading, etc.), and the content contained inside the obtained product, etc. can be reduced. From this viewpoint, the boiling point of the water-soluble nonionic compound is preferably 280°C or lower, preferably 250°C or lower, preferably 230°C or lower, and preferably 210°C or lower. These upper and lower limits can be appropriately combined with each other. Therefore, the boiling point of the water-soluble nonionic compound can be, for example, 125 to 280°C, 125 to 250°C, 150 to 250°C, 150 to 210°C, or 160 to 230°C.

[0087] Within the above range, examples of water-soluble nonionic compounds having a boiling point in the range of 150 to 250°C include 2-pyrrolidone (boiling point 245°C), diethylene glycol (boiling point 244.3°C), formamide (boiling point 210°C), N-methyl-2-pyrrolidone (boiling point 202°C), ethylene glycol (boiling point 197.3°C), dimethyl sulfoxide (boiling point 189°C), propylene glycol (boiling point 188.2°C), N,N-dimethylacetamide (boiling point 165°C), and N,N-dimethylformamide (boiling point 153°C). Examples of water-soluble nonionic compounds having a boiling point in the range of 150 to 210°C include formamide (boiling point 210°C), N-methyl-2-pyrrolidone (boiling point 202°C), ethylene glycol (boiling point 197.3°C), dimethyl sulfoxide (boiling point 189°C), propylene glycol (boiling point 188.2°C), N,N-dimethylacetamide (boiling point 165°C), and N,N-dimethylformamide (boiling point 153°C). The boiling point values ​​can be those recorded in various databases (MERCK INDEX (https: / / merckindex.rsc.org / ), etc.).

[0088] When evaporation is used to remove water in the water removal step, any conditions may be used, including atmospheric pressure, elevated pressure, reduced pressure, or a combination of these. However, among these, evaporation under reduced pressure (evaporation under reduced pressure) is preferred from the viewpoint of energy costs because it allows for a lower heating temperature. The reduced pressure conditions can be adjusted to an appropriate range depending on the water-soluble nonionic compound used. Furthermore, the heating conditions can also be adjusted to an appropriate range depending on the water-soluble nonionic compound used, and can be, for example, 90°C or higher, 100°C or higher, or 120°C or higher. The upper limit is not limited, but can usually be 250°C or lower, or 200°C or lower. These upper and lower limits can be appropriately combined. Therefore, for example, the temperature can be 90 to 250°C, 100 to 200°C, or 120 to 200°C.

[0089] In the water removal step, the water may be removed partially or entirely from the mixture. That is, the water removal rate may be 100%, or less than 100%. This is because the moisture content of the resulting dehydrated cellulosic fiber may be 0%, but as long as it exists as a powder, the moisture content may be greater than 0%. Specifically, as described above, when the total mass of the dehydrated cellulosic fiber is taken as 100% by mass, the water content of the resulting dehydrated cellulosic fiber may be 25% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, 5% by mass or less, or 1% by mass or less.

[0090] If necessary, a water-soluble nonionic compound removal step can be provided after the water removal step, in which the water-soluble nonionic compound is removed. The water-soluble nonionic compound may be removed only partially or entirely from the water-soluble nonionic compound contained in the resulting non-hydrated cellulosic fiber. The water-soluble nonionic compound may be removed by any means, but can be removed by evaporation, as in the case of water removal. In this case, the water-soluble nonionic compound can be removed by evaporation continuously after the water is removed. Furthermore, when the water-soluble nonionic compound removal step is provided, the non-hydrated cellulosic fiber can contain a larger amount of the water-soluble nonionic compound, regardless of the blending ratio (content ratio) of the cellulosic fiber and the water-soluble nonionic compound.

[0091] The non-aqueous cellulosic fiber obtained in the non-aqueous process may contain the cellulosic fiber and the water-soluble nonionic compound, and the quantitative ratio thereof is not limited. However, the total of the cellulosic fiber and the water-soluble nonionic compound is taken as 100% by mass, and the proportion of the cellulosic fiber is taken as R Ｃ The ratio of the water-soluble nonionic compound is R Ｗ In terms of mass%, R Ｃ >R Ｗ That is, the ratio (RＣ / R Ｗ ) is R Ｃ / R Ｗ It is preferable that R is >1. Ｃ / R Ｗ By satisfying the condition of >1, the amount of the water-soluble nonionic compound used can be reduced.

[0092] This ratio (R Ｃ / R Ｗ The lower limit of this ratio (R) can be 1.1 or more, 1.3 or more, 1.5 or more, 2.0 or more, 3.0 or more, 5.0 or more, or 7.5 or more. Ｃ / R Ｗ The upper limit of R can be 10,000 or less, 1,000 or less, 500 or less, 100 or less, 50 or less, 25 or less, or 15 or less. These upper and lower limits can be appropriately combined. Therefore, for example, 1.0≦R Ｃ / R Ｗ ≦10000, and 1.1≦R Ｃ / R Ｗ ≦1000, and 1.1≦R Ｃ / R Ｗ ≦500, and 1.5≦R Ｃ / R Ｗ ≦100, and 2.0≦R Ｃ / R Ｗ ≦50, and 3.0≦R Ｃ / R Ｗ ≦25, and 5.0≦R Ｃ / R Ｗ ≦15, and 7.5≦R Ｃ / R Ｗ It can be ≦15.

[0093] The water content (moisture content) of the non-aqueous cellulosic fiber can be 0%, but the non-aqueous cellulosic fiber is basically required to exist as a powder. This does not preclude the non-aqueous cellulosic fiber from containing water, and the water content of the non-aqueous cellulosic fiber may exceed 0%. In the non-aqueous cellulosic fiber, the water content can be, for example, 25% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less, 5% by mass or less, or 1% by mass or less, where the total mass of the non-aqueous cellulosic fiber is taken as 100% by mass. Cellulose is inherently hydrophilic. Furthermore, since the water-soluble nonionic compound that inhibits the aggregation of the non-aqueous cellulosic fiber does not exert its effect by bonding with the hydroxyl groups of the cellulose, the hydroxyl groups of the cellulose are considered to be present in the same manner as in aqueous cellulosic fiber. For this reason, it is believed that the non-aqueous cellulosic fibers and the powder formed by their aggregation have hygroscopic properties.

[0094] The kneading process is a process of kneading the non-aqueous cellulosic fiber with the copolymer. This kneading process allows for the production of a fibrous composite. As described above, the copolymer before being reacted with the non-aqueous cellulosic fiber has an acid-modified group. This is because the use of the acid-modified group can suppress the alteration and decomposition of the cellulosic fiber during modification. The copolymer and the fibrous composite are as described above.

[0095] The kneading of the non-aqueous cellulosic fiber and the copolymer may be carried out in any manner, and any apparatus may be used. For example, a kneader, an extruder, a kneader, a mixer (such as a high-speed fluid mixer, a paddle mixer, or a ribbon mixer), etc. may be used. These may be used alone or in combination of two or more. When two or more types are used, they may be operated continuously or batchwise (batchwise). Furthermore, the raw materials may be mixed all at once, or may be added and mixed in multiple batches (multi-stage blending). Furthermore, when these apparatuses have screws, they may be single-shaft, twin-shaft, or multi-shaft, with twin-shaft being preferred.

[0096] The kneading conditions are also not limited, and it is sufficient that the copolymer is softened to enable kneading with the non-aqueous cellulosic fiber. However, as described above, from the viewpoint of suppressing decomposition and deterioration of the components constituting the non-aqueous cellulosic fiber (cellulose, lignin, hemicellulose, etc.), the kneading temperature can be set to 220°C or less, 210°C or less, 200°C or less, or 190°C or less. As described above, the lower limit of the kneading temperature is preferably selected depending on the type of copolymer used, but can be, for example, 160°C or more, 165°C or more, 170°C or more, or 175°C or more. These upper and lower limits can be appropriately combined. Therefore, for example, the kneading temperature can be set to 160 to 220°C, 165 to 210°C, 170 to 200°C, or 175 to 190°C.

[0097] Furthermore, as mentioned above, depending on the environment, acid-modified groups are more likely to exist as dicarboxy groups than as carboxy anhydride groups, so it is preferable to use a copolymer in which the probability of the dicarboxy groups existing as carboxy anhydride groups has been increased by dehydrating and ring-closing the groups. That is, it is preferable to use a copolymer that has been ring-closed in the kneading step. This is because using a copolymer in which the probability of the presence of carboxy anhydride groups is high can suppress the decomposition and deterioration of the components (cellulose, lignin, hemicellulose, etc.) that make up the non-aqueous cellulosic fiber. That is, in this method, a copolymer that has been ring-closed in advance may be used in the kneading step, or a ring-closure step in which the copolymer is ring-closed may be provided before the kneading step.

[0098] The ring-closed copolymer is not limited, but for example, in the infrared absorption spectrum, it has a peak at 1790 cm due to C═O of the carboxy anhydride group. －１ The peak height observed in the range of 1700 to 1720 cm due to the C═O of the dicarboxy group －１ Preferably, the copolymer has a peak height equal to or greater than that observed in the graph.

[0099] The ring-closure treatment may be carried out in any manner, but can be achieved by kneading the copolymer at high temperatures, regardless of whether the functional group is in the form of a carboxy anhydride group or a dicarboxy group. Specifically, a copolymer having a ring-closed carboxy anhydride group can be obtained by kneading at a temperature of 180°C or higher. The kneading temperature in the ring-closure treatment can be 185°C or higher, or 190°C or higher. The upper limit of the kneading temperature in the ring-closure treatment is not limited, but can be, for example, 220°C or lower, 210°C or lower, or 205°C or lower. These upper and lower limits can be appropriately combined. Therefore, for example, the temperature can be 185 to 220°C, 185 to 210°C, or 190 to 205°C.

[0100] As explained above, in this method, the esterification step can be composed of steps such as a non-aqueous step, a kneading step, a mixture formation step, a water removal step, and a ring closure step, but other steps can also be included. Examples of other steps include a purification step for purifying cellulosic fibers. The purification step is a step for purifying cellulosic fibers, and can be, for example, a step for increasing the cellulose concentration or a step for increasing the degree of beating. The purification step is preferably carried out before the non-aqueous step.

[0101] The present invention will be specifically described below with reference to examples. [1] Raw material components (1) Cellulose fiber: Microfibrillated fiber (microfibrous cellulose), solid content 14.4% by mass, product name "Celish KY110N" (manufactured by Daicel Miraize Co., Ltd.), which was powdered using a water-soluble nonionic compound (N-methyl-2-pyrrolidone (NMP)).

[0102] (2) Copolymers Having Acid-Modified Groups (2-1) Copolymer 1 (mEPR) Maleic Acid-Modified Ethylene-Propylene Copolymer (mEPR) / Copolymer Backbone: Ethylene-Propylene Copolymer, Mass Average Molecular Weight: 200,000, Type of Carboxylic Anhydride Group: Derived from Maleic Anhydride, Number of Acid-Modified Groups in One Molecule: 2.5

[0103] (2-2) Copolymer 2 (mEBR) Maleic acid-modified ethylene-butene copolymer (mEBR) / Copolymer skeleton: ethylene-butene copolymer, mass average molecular weight: 100,000, type of carboxylic anhydride group: derived from maleic anhydride, number of acid-modified groups per molecule: 5

[0104] (2-3) Copolymer 3 (mEBR) Maleic acid-modified ethylene-butene copolymer (mEBR) / Copolymer skeleton: ethylene-butene copolymer, Mass average molecular weight: 100,000, Type of carboxylic anhydride group: derived from maleic anhydride, Number of acid-modified groups per molecule: 10

[0105] (2-4) Copolymer 4 (mEOR) Maleic acid modified ethylene-octene copolymer (mEOR) / Copolymer skeleton: ethylene-octene copolymer, type of carboxylic anhydride group: derived from maleic anhydride

[0106] (2-5) Copolymer 5 (mSEBS) Maleic acid-modified hydrogenated styrene-butadiene copolymer (mSEBS) / Copolymer skeleton: hydrogenated styrene-butadiene copolymer, type of carboxylic anhydride group: derived from maleic anhydride, number of acid-modified groups per molecule: 10

[0107] (3) Homopolymer having acid-modified group (mPP) Maleic acid-modified polypropylene homopolymer (mPP) / Homopolymer skeleton: polypropylene homopolymer, mass average molecular weight: 70,000, type of carboxylic anhydride group: derived from maleic anhydride, number of acid-modified groups in one molecule: 65

[0108] (4) Resin to be modified: Polyolefin resin (propylene block copolymer, manufactured by Japan Polypropylene, product name "Novatec BC6", MFR 2.7 g / 10 min, melting point 163 ° C)

[0109] [2] Production of fibrous composites (1) Raw materials used The cellulosic fibers used were those described in [1](1) above. Copolymers 1 to 5 described in [1](2) above were used as copolymers. For comparison, a homopolymer (mPP) having an acid-modified group described in [1](3) above was used.

[0110] (2) Apparatus used An apparatus was prepared that has one reaction vessel and can perform mixing, kneading, and vacuum distillation individually or simultaneously in the reaction vessel. The apparatus is designed to perform the mixing and kneading operations by mixing the contents of the reaction vessel using a three-pronged stirrer (motor performance: 0.75 kW, 4 P, 200 V, 60 Hz, 39 A, 1800 rpm / min) and heating the inside of the reaction vessel to a maximum of approximately 300 °C using a heater jacket wrapped around the outer periphery of the reaction vessel. Furthermore, the apparatus is designed to perform the distillation operation by reducing the pressure inside the reaction vessel to a maximum of approximately 0.1 MPa using a connected vacuum pump and heating the inside of the reaction vessel to a maximum of approximately 80 °C using a heater jacket wrapped around the outer periphery of the reaction vessel.

[0111] (3) Operation As shown in the "mass ratio of polymer to cellulosic fiber" in Table 1, both raw materials were charged into a reaction vessel so that the solid content of each cellulosic fiber was 1 part by mass, 5 parts by mass, 10 parts by mass, or 100 parts by mass, assuming 1 part by mass of polymer. Then, with the pressure in the reaction vessel reduced to 0.030 MPa, the stirrer was rotated at 20 Hz, and the vessel was heated to a temperature of 120°C for vacuum distillation. After substantially all of the water contained in the charged raw materials was distilled, the apparatus was stopped, and the reaction products (fibrous composites of Experimental Examples 1 to 8) were removed from the reaction vessel. In all cases, the reaction products were powdery products with a soft texture and a moisture content of 0 (zero).

[0112] [3] Preparation of Thermoplastic Resin Compositions Each of the fibrous composites obtained in [2] above and the polyolefin resin described in [1](3) above were fed into a twin-screw kneading extruder (manufactured by Technovel Co., Ltd., model "KZW15TW-30 / 45MG-NH", screw diameter 15 mm, L / D = 45) and kneaded at an extrusion rate of 0.6 kg / hour and a screw rotation speed of 200 rpm to obtain each of the thermoplastic resin compositions of Experimental Examples 1 to 8. Each thermoplastic resin composition was then injected from the twin-screw kneading extruder into a mold to obtain each of the molded articles for evaluation of Experimental Examples 1 to 8. The amount of fibrous composite added relative to the total amount (100% by mass) of the thermoplastic resin composition is as shown in Table 1.

[0113] [4] Evaluation of Molded Articles for Evaluation (1) Measurement of Flexural Modulus Using each of the molded articles for evaluation in Experimental Examples 1 to 8 obtained in [3] above, a tensile test was performed in accordance with ISO 527-1. The results are shown in Table 1 as "flexural modulus." A molded article for evaluation consisting solely of the resin to be modified (block PP) without the addition of a fibrous composite was molded by injection molding, and when this was measured in the same manner as above, the flexural modulus was 902 (MPa). [Test conditions] Testing equipment: Autograph 50 kN (Shimadzu Corporation, model "AGS-X") Testing temperature: 23°C Specimen shape: ISO multipurpose test specimen Tensile speed (elastic modulus measurement): 1 mm / min Drying conditions: Vacuum drying at 23°C for at least 24 hours

[0114] (2) Measurement of Charpy Impact Strength A Charpy impact strength test (based on ISO 179) was carried out using each of the evaluation molded articles of Experimental Examples 1 to 8 obtained in [3] above. Test pieces with a notch (Type A) were used, and the test was carried out by the edgewise test method at a test temperature of 23°C. The results are shown in Table 1 as "Charpy." Furthermore, an evaluation molded article consisting of only the resin to be modified (block PP) without the addition of a fibrous composite was molded by injection molding, and this was measured in the same manner as above. The Charpy impact strength was 59.0 (kJ / m ２ ) was.

[0115]

[0116] [5] Effects of Examples (1) From the results of Table 1, a graph comparing Experimental Examples 1 to 2, 4, 6 to 8 in which the polymer (copolymer or homopolymer):cellulosic fiber ratio was 1:10 is shown in Figure 1. From Figure 1, it can be seen that compared to Experimental Example 8 in which the component compounded with the cellulosic fiber was a homopolymer, Experimental Examples 1 to 2, 4 and 6 in which a copolymer was compounded all significantly suppressed a decrease in impact resistance while improving the flexural modulus. Specifically, the flexural modulus obtained at an addition amount of 5 mass% in Experimental Example 8 was 1242 MPa, and the Charpy impact strength at that time was 4.9 kJ / m ２ When the flexural modulus of elasticity of Experimental Example 8, 1242 MPa, is used as a reference, the calculated value of the Charpy impact strength obtained in each Experimental Example calculated from the graph in FIG. 1 is as follows: Experimental Example 1: 22.6 kJ / m ２ , Experimental Example 2: 16.9 kJ / m ２ , Experimental Example 4: 27.0 kJ / m ２ , Experimental Example 6: 16.2 kJ / m ２ , Experimental Example 7: 17.3 kJ / m ２ It can be seen that the impact resistance values ​​obtained are significantly higher, 3.3 to 5.5 times, than those of Experimental Example 8. Among these, it can be seen that particularly remarkable results were obtained in Experimental Example 4 (using Copolymer 3).

[0117] (2) Figure 2 shows a graph comparing Experimental Examples 3 to 5 and Experimental Example 8, which are examples using fibrous composites that utilize Copolymer 3, which exhibited the most excellent effect in (1) above, and in which the polymer (copolymer or homopolymer):cellulosic fiber ratio was 1:5 to 1:100. As can be seen from Figure 2, compared to Experimental Example 8, which used mPP (acid-modified homopolymer) as the composite component, Experimental Example 5, which used mEBR (acid-modified copolymer) as the composite component, exhibited higher Charpy impact strength across the entire range than Experimental Example 8, even in Experimental Example 5, where the composite component ratio was as low as 1:100. This shows that the use of an acid-modified copolymer as the polymer to be composited with the cellulosic fiber significantly improved impact resistance.

[0118] The present invention is not limited to the specific examples described above, and various modifications can be made within the scope of the present invention depending on the purpose and application.

[0119] The foregoing examples are for illustrative purposes only and are not to be construed as limiting the invention. While the invention has been described with reference to exemplary embodiments, it is understood that the language used in describing and illustrating the invention is descriptive and exemplary, rather than limiting. As detailed herein, changes may be made within the purview of the appended claims without departing from the scope or spirit of the invention in its form. While the description of the invention has referred to specific structures, materials, and examples, it is not intended that the invention be limited to the disclosure set forth herein; rather, the invention is intended to cover all functionally equivalent structures, methods, and uses within the scope of the appended claims.

Claims

1. A fibrous composite comprising a cellulosic fiber and a copolymer having an acid-modified group bonded together, wherein the acid-modified group is a carboxyl anhydride group and / or a carboxyl group derived from a carboxyl anhydride group, and wherein the cellulosic fiber and the copolymer are bonded together by an ester bond between a hydroxyl group of the cellulose constituting the cellulosic fiber and the acid-modified group.

2. A fibrous composite according to claim 1, wherein the copolymer has a skeleton of an ethylene-propylene copolymer, an ethylene-butene copolymer, an ethylene-octene copolymer, or a styrene-ethylene / butylene-styrene copolymer.

3. The fibrous composite according to claim 1, wherein the copolymer has structural units derived from at least two types of monomers differing in the number of carbon atoms by two or more.

4. The fibrous composite according to claim 1, wherein the number of acid-modifiable groups is five or more.

5. The fibrous composite according to claim 1, which is a modifier for olefin resins.

6. A powder characterized by being an aggregate of the fibrous composites according to any one of claims 1 to 5.

7. A method for producing a fibrous composite according to any one of claims 1 to 5, comprising a modification step for forming the ester bond.

Images