Thermoplastic resin composition and method for producing same

Abstract

This thermoplastic resin composition and this method for producing the same can blend cellulose fibers in a resin without relying on denaturation of cellulose by using a compositional make-up different from conventional ones. This thermoplastic resin composition comprises a thermoplastic resin as a continuous phase and cellulose fibers dispersed in the continuous phase. The thermoplastic resin composition is obtained by kneading a thermoplastic resin in which the denaturation rate of hydroxy groups provided to cellulose contained in the cellulose fibers is at most 0.5% (including 0%) or which forms a continuous phase, and a fibrous substance that forms a disperse phase. The fibrous substance includes cellulose fibers and a water-soluble nonionic compound that has a boiling point higher than 100°C and is interposed between the cellulose fibers.

Description

Thermoplastic resin composition and method for producing same

[0001] The present invention relates to a thermoplastic resin composition and a method for producing the same, and more particularly to a thermoplastic resin composition using cellulosic fibers and a method for producing the same.

[0002] In recent years, cellulose fibers have been used in aqueous applications to control viscoelasticity, such as in thickeners. Meanwhile, in composite material applications, for example, cellulose fibers have long been proven to be excellent reinforcing materials for resins, 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. Specifically, the cellulose contained in cellulose fibers is a polysaccharide and contains many hydroxyl groups derived from sugar chains. This makes them highly hydrophilic, making them difficult to disperse in resins and difficult to incorporate into resins. 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] The above-mentioned Patent Document 1 discloses a technique (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 highly dispersible fibers 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 higher. This disclosure mentions (

[0012] ) that the introduction of alkanoyl groups such as acetyl groups (i.e., chemically modifying the hydroxyl groups) blocks the hydroxyl groups of the cellulose molecules, thereby suppressing the hydrogen bonding strength of the cellulose molecules. The above-mentioned Patent Document 3 discloses a modified cellulose nanofiber ([Claim 1], etc.) having 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 carboxyl groups of the polycarboxylic acid other than the carboxyl 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] ).

[0005] The techniques described in Patent Documents 1 to 3 all involve modifying cellulose by chemically modifying hydroxyl groups, etc., to enable cellulose fibers to be dispersed in a resin. These techniques make it possible to handle cellulose fibers in a non-aqueous system, thereby resolving the aforementioned problems associated with resin formulation. Thus, while various methods are currently being investigated for modifying cellulose, it remains unclear which techniques and solutions are appropriate and practical. Therefore, there is a need for a wide variety of options in order to have more options for the future.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a thermoplastic resin composition that can be blended with cellulosic fibers without modifying the cellulose, using a configuration different from conventional ones, and a method for producing the same.

[0007] That is, the present invention includes the following: [1] A thermoplastic resin composition comprising a thermoplastic resin as a continuous phase and cellulosic fibers dispersed within the continuous phase, characterized in that the modification rate of hydroxy groups of the cellulose constituting the cellulosic fibers is 0.5% or less (including 0%). [2] A thermoplastic resin composition obtained by kneading a thermoplastic resin as a continuous phase and a fibrous material as a dispersed phase, characterized in that the fibrous material contains cellulosic fibers and a water-soluble nonionic compound having a boiling point exceeding 100°C interposed between the cellulosic fibers. [3] A thermoplastic resin composition having a solubility in water of 0.5 g / 100 gH ２The thermoplastic resin composition according to [2], wherein the water-soluble nonionic compound accounts for 50% by mass or less when the total of the cellulosic fiber and the water-soluble nonionic compound is taken as 100% by mass. [4] The thermoplastic resin composition according to [2], wherein the water-soluble nonionic compound accounts for 50% by mass or less when the total of the cellulosic fiber and the water-soluble nonionic compound is taken as 100% by mass. [5] The thermoplastic resin composition according to [2], wherein the water-soluble nonionic compound has a boiling point of 150°C or more and 230°C or less. [6] The fibrous material according to [2], wherein the water-soluble nonionic compound is at least one of N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide. [7] The fibrous material according to [1] or [2], wherein the thermoplastic resin is at least one of polyolefin, polyamide, and polyester. [8] A method for producing a thermoplastic resin composition, comprising a kneading step of kneading a thermoplastic resin that forms a continuous phase with a fibrous material that forms a dispersed phase, wherein the fibrous material contains cellulosic fibers and a water-soluble nonionic compound having a boiling point of over 100°C that is interposed between the cellulosic fibers. [9] A method for producing a thermoplastic resin composition according to [8], comprising a fibrous material formation step of obtaining the fibrous material, wherein the fibrous material formation step comprises a water removal step of removing water from a mixture in which the cellulosic fibers, the water-soluble nonionic compound, and water are coexistent.

[10] A method for producing a thermoplastic resin composition, comprising: a step of kneading a thermoplastic resin that forms a continuous phase with a fibrous material that forms a dispersed phase; Ｃ % by mass, and the proportion of the water-soluble nonionic compound is R Ｗ When expressed as mass%, R Ｃ >R Ｗ The method for producing a thermoplastic resin composition according to claim [9],

[0008] According to the fibrous material and the method for producing the fibrous material of the present invention, a constitution different from that of the conventional art allows cellulosic fibers to be blended with a resin without relying on cellulose modification.

[0009] 1 is a graph showing the correlation between flexural modulus and Charpy impact strength for Experimental Examples 2 and 4 to 6. 2 is a graph showing the correlation between flexural modulus and Charpy impact strength for Experimental Examples 1 to 3.

[0010] 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.

[0011] [1] Thermoplastic Resin Composition The thermoplastic resin composition of the present invention comprises a thermoplastic resin as a continuous phase and cellulosic fibers dispersed within the continuous phase, and is characterized in that the modification rate of hydroxy groups of the cellulose constituting the cellulosic fibers is 0.5% or less (including 0%). The cellulosic fibers can be contained in a fibrous material together with a water-soluble nonionic compound. In this case, the thermoplastic resin composition of the present invention is obtained by kneading a thermoplastic resin as a continuous phase and a fibrous material as a dispersed phase, and the fibrous material is characterized in that it contains cellulosic fibers and a water-soluble nonionic compound having a boiling point above 100°C interposed between the cellulosic fibers.

[0012] (1) Cellulosic Fibers The term "cellulosic fibers" as used herein refers to fibrous materials primarily composed of cellulose. In this specification, cellulosic fibers are expressed as follows, as necessary. That is, cellulosic fibers that are raw materials for fibrous materials and that require the coexistence of water in order to inhibit aggregation in the absence of a water-soluble nonionic compound are also referred to as "aqueous cellulosic fibers." Furthermore, cellulosic fibers that constitute fibrous materials and that no longer require the coexistence of water due to the coexistence of a water-soluble nonionic compound are also referred to as "non-aqueous cellulosic fibers." When used interchangeably, these aqueous and non-aqueous cellulosic fibers are also simply referred to as "cellulosic fibers."

[0013] The maximum length of cellulosic fibers is typically 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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 material, the resin for molding is heated (heated to a temperature at which the resin can flow) during molding, etc., and components constituting the cellulosic fibers, such as lignin, are decomposed. 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 (lignin, etc.) 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.

[0023] 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 a resin for molded bodies blended with a fibrous material, lignin and the like are decomposed. As a result, the mechanical strength of the obtained 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 made smaller than in the former case.

[0024] As mentioned above, cellulosic fibers are fibrous materials primarily composed of cellulose. However, the percentage of cellulose contained in the cellulosic fibers is not limited. For example, it can be 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 cellulose is determined by immersing the fibers in a 17.5% NaOH aqueous solution for 2 hours, adding an equal volume of water to the NaOH aqueous solution, and boiling the resulting solution for 1 hour. The dried residue (dried at 80°C or less) contained in the resulting liquid is used as the cellulose. 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 containing sodium chlorite and acetic acid in a mass ratio of 5:1, heated at 80°C for one hour, and then filtered to obtain a residue. The same procedure is repeated four times to measure the amount of cellulose contained in the residue after lignin removal. However, since the number of cellulosic fibers constituting the fibrous material is large, and it is sufficient for the fibrous material to ultimately be formed, there is no practical point in specifying the cellulose content of each cellulosic fiber. Similarly, when using plant-derived cellulosic fibers, 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. These fibers can be used in combination, so it is sufficient for the fibrous material to ultimately be formed, and there is no practical point in specifying the average value. Note that, as long as the fibrous material ultimately forms a fibrous material, it is acceptable for the fibrous material to contain hemicellulose, lignin, and components derived from these.

[0025] Furthermore, the morphology of the cellulosic fibers 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 morphology of the fibrous material in a fibrous form. 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 material is large, and it is sufficient for the resulting fibrous material to be formed, there is no practical point in specifying the aspect ratio of each individual cellulosic fiber. 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. These fibers can be mixed and used, and therefore, there is no practical point in specifying the average value of the aspect ratios as long as the resulting fibrous material is formed.

[0026] (2) Water-soluble nonionic compound The "water-soluble nonionic compound" is a nonionic compound that is soluble in water and has a boiling point exceeding 100°C (a temperature exceeding 100°C). As mentioned above, aqueous cellulosic fibers are fibrous materials that require the coexistence of water in order to suppress aggregation in the absence of a water-soluble nonionic compound. In this regard, water-soluble nonionic compounds can be dissolved in water coexisting with aqueous cellulosic fibers, thereby forming a dispersed state in which the cellulosic fibers, water, and the water-soluble nonionic compound coexist. Furthermore, since the water-soluble nonionic compound has a boiling point exceeding 100°C, solvent removal from a state in which water and the water-soluble nonionic compound coexist can preferentially remove water with a relatively low boiling point. As a result, water is removed from a mixture in which the cellulosic fibers, water, and the water-soluble nonionic compound coexist, forming a fibrous material in which the nonaqueous cellulosic fibers and the water-soluble nonionic compound coexist.

[0027] Furthermore, the water-soluble nonionic compound is a water-soluble but nonionic compound. That is, it is a compound that can be dissolved in water without ionization. Because the compound is nonionic, when water is removed from a mixture of cellulosic fibers, water, and the water-soluble nonionic compound, it remains in the gaps between the cellulosic fibers, preventing the cellulosic fibers from aggregating. As a result, the cellulosic fibers are not agglomerated and remain separate, allowing the formation of a fibrous material.

[0028] Furthermore, the fibrous material can be formed in the above-described form without chemically bonding (chemically reacting) the water-soluble nonionic compound to the cellulosic fiber or its constituent components. That is, by utilizing an interpenetrating structure in which the water-soluble nonionic compound penetrates between aqueous cellulosic fibers, it is possible to obtain non-aqueous cellulosic fibers, i.e., fibrous materials, that can maintain a dispersed state without the aid of chemical bonds, using aqueous cellulosic fibers, which cannot maintain a dispersed state without the aid of water. As a result, while aqueous cellulosic fibers must be handled as a liquid or fluid, the fibrous material can be handled as a powder. Furthermore, while aqueous cellulosic fibers require the coexistence of a large amount of water, fibrous materials do not, which allows for a significant reduction in the mass of the cellulosic fiber when handling it. Furthermore, the elimination of water eliminates the need for refrigeration, allowing for storage at room temperature and normal pressure. Thus, powderization can significantly improve the handleability of cellulosic fibers.

[0029] As mentioned above, the water-soluble nonionic compound inhibits the aggregation of cellulosic fibers within the fibrous material without bonding with the cellulosic fibers (no IR shift due to chemical bonding is observed). From this, it is thought that the cellulosic fibers and the water-soluble nonionic compound at least form a structure (interpenetrating structure) in which the cellulosic fibers and the water-soluble nonionic compound interpenetrate each other, and this interpenetrating structure is thought to be obtained by a coating structure in which the water-soluble nonionic compound covers the cellulosic fibers. This is derived from the fact that the fibrous material of the present invention exhibits excellent dispersibility in resin. In other words, the fibrous material of the present invention can obtain excellent dispersibility in resin by having a coating structure in which the water-soluble nonionic compound covers the outer periphery of the cellulosic fibers.

[0030] 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.

[0031] 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 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 aqueous cellulosic fibers into nonaqueous 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.

[0032] 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 water in the aqueous cellulosic fiber contained in a mixture of aqueous cellulosic fiber and water 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 mixture, a higher solubility is preferable, and 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.

[0033] 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.

[0034] As mentioned above, the boiling point of the water-soluble nonionic compound may be above 100°C. However, from the viewpoint of facilitating separation from water, a larger boiling point difference is preferable. 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, there is no upper limit to the boiling point of the water-soluble nonionic compound. However, when considering the case where the water-soluble nonionic compound is used as a resin modifier, it is preferable that the compound can be evaporated by heating during mixing (melting and kneading, etc.), thereby lowering the content inside the resulting product. 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. 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.

[0035] Therefore, within the above range, 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 (MNP, boiling point 202°C), ethylene glycol (boiling point 197.3°C), dimethyl sulfoxide (DMSO, boiling point 189°C), propylene glycol (boiling point 188.2°C), N,N-dimethylacetamide (DMAc, boiling point 165°C), N,N-dimethylformamide (DMF, boiling point 153°C), etc. In addition to these, 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), etc. The boiling point values ​​can be those recorded in various databases (MERCK INDEX (https: / / merckindex.rsc.org / ) and the like).

[0036] (3) Fibrous Material The fibrous material contains the above-mentioned cellulosic fiber and the above-mentioned water-soluble nonionic compound, and has an interpenetrating structure in which the water-soluble nonionic compound penetrates between the cellulosic fibers. That is, within the fibrous material, the cellulosic fiber and the water-soluble nonionic compound form a structure in which they penetrate each other (interpenetrating structure) without chemical bonding. By utilizing this interpenetrating structure, the fibrous material can be made into a non-aqueous cellulosic fiber that can maintain a dispersed state without coexisting with water, even though the aqueous cellulosic fiber is used as the raw material, without the aqueous cellulosic fiber bonding with the water-soluble nonionic compound, in other words, without denaturing the cellulose contained in the aqueous cellulosic fiber. In other words, because the fibrous material has an interpenetrating structure in which the water-soluble nonionic compound penetrates between the cellulosic fibers, it can be handled in a non-aqueous system without denaturing the cellulose, and can be blended with a resin. In the fibrous material, the ratio of the amount of the cellulosic fiber to the amount of the water-soluble nonionic compound is not limited. However, the total amount 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 (R Ｃ / 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.

[0037] 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 ＷThe 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.

[0038] The water content (moisture content) of a fibrous material can be 0%, but the fibrous material basically only needs to exist as a powder. As long as it exists as a powder, it is not prohibited from containing water, and the water content of the fibrous material may exceed 0%. In a fibrous material (and further, a powder, as described below), 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, assuming that the total mass of the fibrous material is 100% by mass. Cellulose is inherently hydrophilic. Furthermore, since the water-soluble nonionic compounds that inhibit the aggregation of cellulosic fibers in a fibrous material do not exert their effect by bonding with the hydroxyl groups of cellulose, the hydroxyl groups of cellulose are considered to exist in the same manner as aqueous cellulosic fibers. Therefore, the fibrous material and its aggregate, the powder, are considered to be hygroscopic.

[0039] In the thermoplastic resin composition of the present invention, the fibrous material (cellulosic fiber) can be used as a modifier for thermoplastic resins, a carrier for additives, or the like. Among the above, the modifier is a component that can modify the properties of a thermoplastic resin. The fibrous material (cellulosic fiber) can be used as a modifier for fiber-reinforced resins, that is, a modifier that improves the mechanical strength properties of molded bodies obtained from the resin for molded bodies after blending with a thermoplastic resin that is a resin raw material for molded bodies. Examples of mechanical strength properties include an improvement in flexural modulus. Further examples of mechanical strength properties include an improvement in impact resistance to suppress a decrease in impact resistance that occurs as the flexural modulus increases.

[0040] The mechanism by which the effect of suppressing the decrease in impact resistance of the resulting resin for moldings when a fibrous substance is blended with a resin raw material for moldings is not clear, but the following mechanism can be considered. That is, as mentioned above, the fibrous substance has a water-soluble nonionic compound interposed between the cellulosic fibers. Looking at this situation microscopically, it can be said that the water-soluble nonionic compound coats each individual cellulosic fiber. Furthermore, when a fibrous substance is blended with a resin raw material for moldings, it is thought that heating during resin kneading causes some or all of the water-soluble nonionic compound to evaporate, forming gaps between the cellulosic fibers and the matrix (e.g., resin) in which the fibrous substance is blended. It is thought that such gaps can reduce the number of fracture initiation points compared to when the cellulosic fibers are blended in contact with the matrix. Therefore, it is thought that the effect of suppressing the decrease in impact resistance can be exerted.

[0041] Furthermore, when the thermoplastic resin is a resin for use in paints, the viscosity of the paint obtained from the paint resin after blending can be modified. Examples of viscosity modification include thickening, imparting or strengthening thixotropy, etc. Similarly, when the thermoplastic resin is a resin for use in adhesives, the viscosity of the adhesive obtained by blending can be modified. Examples of viscosity modification include thickening, imparting or strengthening thixotropy, etc.

[0042] Among the above, the carrier for additives is a carrier when adding additives to a thermoplastic resin. The type of additive is not limited, but examples include flame retardants, flame retardant assistants, fillers, colorants, antibacterial agents, antistatic agents, etc. These may be used alone or in combination of two or more.

[0043] (4) Thermoplastic Resin The "thermoplastic resin" forms a continuous phase in the thermoplastic resin composition of the present invention, in contrast to the dispersed phase of the fibrous material or the cellulosic fiber. Thermoplastic resins are polymers formed by the polymerization of monomers, and are thermoplastic. The type of thermoplastic resin is not limited, but examples include thermoplastic resins and thermoplastic elastomers. These may be used alone or in combination of two or more. The thermoplastic resin system is not limited, but examples include polyolefins, polyamides, polyesters, polyurethanes, polystyrenes, polyvinyl chlorides, and the like. These may be used alone or in combination of two or more. Among these, the thermoplastic resin system is preferably at least one of polyolefins, polyamides, and polyesters, and more preferably polyolefins, from the viewpoints of availability and versatility for use in a wide variety of applications.

[0044] With regard to the polyolefins described above, the type of olefin 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, and the like. These polymers may be used alone or in combination of two or more. Furthermore, when two or more types are used, this includes both pellets made of mixed resins and pellet mixtures.

[0045] 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.

[0046] 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. １４ This 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.

[0047] 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.

[0048] 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.

[0049] The properties of plant-derived PE are not limited, but include a density of 0.942 g / cm ３ Preferably, 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.

[0050] 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.

[0051] 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.

[0052] The properties of the polyolefin used as the thermoplastic resin in the present invention 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.

[0053] The polyamides described above are not limited to specific types, and examples include those containing an aliphatic skeleton (commonly known as "nylons") and those composed solely of an aromatic skeleton (commonly known as "aramids"). Examples of polyamides containing an aliphatic skeleton include those synthesized by the polycondensation reaction of ω-amino acids using lactam as a raw material (e.g., PA6, PA11, PA12, etc., commonly known as "n-nylons") and those synthesized by the co-polycondensation reaction of diamines and dicarboxylic acids (e.g., PA66, PA610, PA6T, etc., commonly known as "n,m-nylons"). Examples of polyamides composed solely of an aromatic skeleton include para-aramids synthesized by the co-polycondensation of p-phenylenediamine and terephthalic acid chloride, and meta-aramids synthesized by the co-polycondensation of m-phenylenediamine and isophthalic acid chloride. These polyamides may be used alone or in combination. The polyamides described above are widely used in fiber applications as well as resin applications. That is, the thermoplastic resin composition of the present invention can also be used as a fiber raw material.

[0054] The polyesters described above are not limited to specific types, and examples include those synthesized by a dehydration condensation reaction between a dicarboxylic acid and a diol, such as polyethylene terephthalate synthesized from terephthalic acid and ethylene glycol, polybutylene terephthalate synthesized from terephthalic acid and 1,4-butanediol, polytrimethylene terephthalate synthesized from terephthalic acid and 1,3-propanediol, polyethylene naphthalate synthesized from 2,6-naphthalenedicarboxylic acid and ethylene glycol, polybutylene naphthalate synthesized from 2,6-naphthalenedicarboxylic acid and 1,4-butanediol, and polylactic acid synthesized by polymerizing lactic acid via an ester bond. Other examples of polyesters include unsaturated polyesters containing unsaturated groups and modified polyesters modified with alkyd resins, epoxy resins, or the like. These may be used alone or in combination of two or more. The polyesters described above are widely used in resin applications, particularly in engineering plastics, which are excellent in strength and heat resistance. That is, the thermoplastic resin composition of the present invention can also be used as a raw material for engineering plastics.

[0055] (5) Thermoplastic Resin Composition The thermoplastic resin composition of the present invention is obtained by kneading a thermoplastic resin as a continuous phase and a fibrous material as a dispersed phase. That is, the thermoplastic resin composition comprises a thermoplastic resin as a continuous phase and a fibrous material dispersed within the continuous phase. Here, the fibrous material contains cellulosic fibers and a water-soluble nonionic compound, and has an interpenetrating structure in which the water-soluble nonionic compound penetrates between the cellulosic fibers. This interpenetrating structure allows the cellulosic fibers to be handled in a non-aqueous system without denaturing the cellulose contained therein, and thus can be incorporated into the thermoplastic resin by kneading. Furthermore, in the fibrous material having an interpenetrating structure, the water-soluble nonionic compound is not bonded to the cellulosic fibers and may evaporate at the temperature during kneading with the thermoplastic resin. In this case, the water-soluble nonionic compound is removed from the fibrous material, and the thermoplastic resin composition of the present invention comprises a thermoplastic resin as a continuous phase and cellulosic fibers dispersed within the continuous phase. The thermoplastic resin composition exhibits suitable strength due to the thermoplastic resin being fiber-reinforced by the incorporated fibrous material and / or cellulosic fibers.

[0056] The amount of fibrous material and / or cellulosic fiber blended is not limited, but can be 50% by mass or less, 40% by mass or less, 30% by mass or less, or 20% by mass or less, assuming the total amount with the thermoplastic resin as 100% by mass. The amount of this fibrous material and / or cellulosic fiber blended can further be 0.5% by mass or more, 1% by mass or more, 3% by mass or more, or 5% by mass or more. These upper and lower limits can be appropriately combined. Thus, for example, the amount can be 0.5 to 50% by mass, 1 to 40% by mass, 3 to 30% by mass, or 5 to 20% by mass.

[0057] Regarding the performance of a thermoplastic resin composition, the "strength" of the resulting molded article, which relates to its mechanical strength, can usually be evaluated by its elasticity. The elasticity can be expressed as the flexural modulus measured by a flexural modulus test (JIS K7171, ISO 178, ASTM D790). The flexural modulus is not limited, but can be 1000 MPa or more, 1100 MPa or more, 1150 MPa or more, or 1200 MPa or more. This flexural modulus can be further set to 4000 MPa or less, 3500 MPa or less, 3000 MPa or less, or 2500 MPa or less. These upper and lower limits can be appropriately combined. Therefore, for example, the flexural modulus can be set to 1000 to 4000 MPa, 1100 to 3500 MPa, 1150 to 1600 MPa, or 1200 to 1550 MPa.

[0058] Regarding the performance of a thermoplastic resin composition, the "rigidity" relating to the mechanical strength properties of the resulting molded article can usually be evaluated by impact resistance, which can be expressed as an impact resistance value measured by a Charpy impact test (JIS K7111-1, ISO 179-1, ASTM D6110). The impact resistance value is not limited, but is preferably 10 kJ / m ２ and 12 kJ / m or more. ２ and 15 kJ / m or more. ２ and 18 kJ / m or more. ２ This impact resistance value can be further increased to 45 kJ / m or more. ２ and 40 kJ / m or less. ２ and 35 kJ / m ２ These upper and lower limits can be appropriately combined. Therefore, for example, 10 to 45 kJ / m ２ and 12 to 40 kJ / m ２ and 18 to 35 kJ / m ２ It can be said that:

[0059] [2] Method for producing a thermoplastic resin composition The method for producing a thermoplastic resin composition of the present invention includes a kneading step. The "kneading step" is a step of kneading a thermoplastic resin that forms a continuous phase with a fibrous material that forms a dispersed phase. The fibrous material used in the kneading step includes cellulosic fibers and a water-soluble nonionic compound with a boiling point of over 100°C that is interposed between the cellulosic fibers. In this fibrous material, the water-soluble nonionic compound penetrates between the cellulosic fibers without chemical bonding, thereby forming an interpenetrating structure.

[0060] The water-soluble nonionic compound contained in the fibrous material forms an interpenetrating structure with the cellulosic fiber, thereby coating the hydroxyl groups of the cellulose contained in the cellulosic fiber and suppressing the hydrophilicity of the cellulosic fiber. Therefore, in the kneading process, the fibrous material, although made from aqueous cellulosic fiber as the raw material, can behave as a non-aqueous cellulosic fiber that can maintain a dispersed state without coexisting with water, and can be dispersed approximately uniformly in the thermoplastic resin that serves as the continuous phase.

[0061] In the kneading step, the method for kneading the thermoplastic resin and the fibrous material is not limited, and examples thereof include a melt-kneading method using a kneader such as a single-screw kneader extruder, a twin-screw kneader extruder, or a multi-screw kneader extruder; a method in which each component is dissolved or dispersed in a solvent or solvent and then the solvent or solvent is removed by heating; and a dry blending method in which each component is stirred and mixed at a temperature at which the resin components do not melt to form a homogeneous state. Of these, the melt-kneading method using a kneader is preferred from the viewpoint of workability. Furthermore, the thermoplastic resin composition obtained by melt-kneading can be, for example, pelletized and directly extruded into a mold or the like to form a molded product.

[0062] In the kneading step, the kneading of the thermoplastic resin and the fibrous material may be carried out under any temperature conditions, but can usually be set within an appropriate range depending on the softening temperature or melting temperature of the thermoplastic resin used. For example, when the thermoplastic resin is a polyolefin, the temperature can be 160°C or higher, 180°C or higher, or 200°C or higher. The upper limit is not limited, but usually it can be 250°C or lower, or 200°C or lower. When the thermoplastic resin is a polyamide or polyester, the temperature can be 180°C or higher, 200°C or higher, or 220°C or higher. The upper limit is not limited, but usually it can be 280°C or lower, or 270°C or lower. These upper and lower limits can be appropriately combined. Therefore, for example, the temperature can be 160 to 280°C, 180 to 270°C, or 200 to 250°C.

[0063] The method for producing a thermoplastic resin composition may include a fibrous material formation step. The "fibrous material formation step" is a step for obtaining the above-described fibrous material. In this fibrous material formation step, a mixture in which cellulosic fibers, a water-soluble nonionic compound, and water coexist can be formed. In forming the fibrous material, the mixture may be formed by any method, for example, (1) mixing aqueous cellulosic fibers (including cellulosic fibers and water) with a water-soluble nonionic compound. Alternatively, (2) mixing cellulosic fibers with water and a water-soluble nonionic compound. Furthermore, (3) mixing cellulosic fibers with a mixture of a water-soluble nonionic compound and water. In the case of (1) above, the water-soluble nonionic compound may be added to the aqueous cellulosic fibers while mixing, or the mixture of a water-soluble nonionic compound and water may be added to the aqueous cellulosic fibers while mixing. These may be used alone or in combination of two or more.

[0064] The fibrous material forming step can include a water removal step. The "water removal step" is a step of removing water from a mixture of cellulosic fibers, a water-soluble nonionic compound, and water. The cellulosic fibers and the water-soluble nonionic compound are as described above.

[0065] In the water removal step, water may be removed 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 may be used alone or in combination of two or more. Among these, evaporation is preferred. As mentioned above, the water-soluble nonionic compound is a water-soluble, nonionic compound with a boiling point exceeding 100°C. Therefore, by utilizing evaporation, water having a boiling point lower than that of the water-soluble nonionic compound can be preferentially removed while leaving the water-soluble nonionic compound in the mixture.

[0066] In the water removal step, all of the water contained in the mixture may be removed, but not all of it. That is, the water removal rate may be 100%, but it may also be less than 100%. This is because the moisture content of the resulting fibrous material 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 mass of the entire fibrous material is taken as 100% by mass, the water content of the resulting fibrous material 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.

[0067] The water removal step can be carried out simultaneously with the mixture formation step, or can be carried out substantially after the mixture formation step. That is, the mixture may be formed before the water removal step or simultaneously with the water removal step. Simultaneous carrying out of the mixture formation step and the water removal step refers to cases in which the formation of the mixture and the removal of water from the mixture proceed simultaneously. For example, the components constituting the mixture may be added during the water removal step. That is, cases 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 cases 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 water is added while beating to increase the degree of beating (a process to increase the degree of defibration). In this way, by improving the dissociation state of the cellulosic fibers, mutual penetration by the water-soluble nonionic compound can be more reliably achieved.

[0068] In addition, an embodiment in which a mixture is formed simultaneously with the water removal process (the water removal process and the mixture formation process proceed simultaneously) includes a case in which the components constituting the mixture are added during the water removal process. That is, a case in which a water-soluble nonionic compound is continuously added during the water removal process. Furthermore, when the water content of the aqueous cellulose fiber used as a raw material is reduced, water can be added to perform a pretreatment that more reliably dissociates the cellulose fibers contained in the aqueous cellulose fiber. By using a mixture in which the dispersibility of the cellulose fibers contained in the aqueous cellulose fiber is improved, mutual penetration by the water-soluble nonionic compound can be more reliably achieved.

[0069] The amount of the water-soluble nonionic compound contained in the mixture is not limited as long as the above-mentioned fibrous material is obtained as a result, but the water-soluble nonionic compound can be blended in the mixture so that the cellulosic fiber and the water-soluble nonionic compound are blended in the resulting fibrous material. That is, as described above, the total of the cellulosic fiber and the water-soluble nonionic compound is taken as 100 mass %, and the proportion of the cellulosic fiber is R Ｃ The ratio of the water-soluble nonionic compound is R Ｗ In terms of mass%, R Ｃ / 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.

[0070] Any device may be used to mix the mixture, and examples thereof include mixers, kneaders, extruders, kneaders, mixers (high-speed fluid mixers, paddle mixers, ribbon mixers, 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 screws, they may be single-shaft, twin-shaft, or multi-shaft, with twin-shaft being preferred.

[0071] 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.

[0072] If necessary, a water-soluble nonionic compound removal step can be provided to remove the water-soluble nonionic compound. The removal of the water-soluble nonionic compound may involve removing only a portion or all of the water-soluble nonionic compound contained in the fibrous material. When the water-soluble nonionic compound is removed, the thermoplastic resin composition can have a configuration in which the cellulosic fibers contained in the fibrous material remain dispersed as fibrous materials in the continuous phase of the thermoplastic resin, thereby allowing the thermoplastic resin composition to have the cellulosic fibers dispersed in the continuous phase of the thermoplastic resin.

[0073] The water-soluble nonionic compound removal step can be carried out simultaneously with the mixture formation step. That is, the temperature conditions in the kneading step may exceed the boiling point of the water-soluble nonionic compound contained in the fibrous material. In this case, since the water-soluble nonionic compound is not chemically bonded to the cellulosic fiber, it is evaporated under the temperature conditions during kneading and removed from the fibrous material. Alternatively, the water-soluble nonionic compound removal step can be carried out after the water removal step.

[0074] The water-soluble nonionic compound may be removed by any means, but can be removed by evaporation, as in the case of removing water. In this case, after water is removed by evaporation, the water-soluble nonionic compound can be continuously removed by evaporation. Furthermore, when a water-soluble nonionic compound removal step is provided, the fibrous material 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.

[0075] Alternatively, in addition to the water removal step, mixture formation step, and other steps, a purification step of purifying the cellulosic fibers may be included. The purification step is a step of purifying the cellulosic fibers, and may be, for example, a step of increasing the cellulose concentration or a step of increasing the degree of beating. The purification step is preferably carried out before the mixture formation step.

[0076] The present invention will be specifically described below with reference to examples. [1] Production of fibrous material (1) Raw material components (1-1) Microfibrillated fiber (microfibrous cellulose), solid content concentration 14.4 mass%, trade name "Celish KY110N" (manufactured by Daicel Miraize Co., Ltd.) (1-2) Water-soluble nonionic compound "NMP": N-methyl-2-pyrrolidone "DMF": N,N-dimethylformamide "DMAc": N,N-dimethylacetamide "DMSO": dimethyl sulfoxide

[0077] (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.

[0078] (3) As shown in Table 1, both raw materials were charged into a reaction vessel so that the solid content of the cellulosic fiber was 1 part by mass, 10 parts by mass, or 1,000 parts by mass when each water-soluble nonionic compound (NMP, DMF, DMAc, and DMSO) was 1 part by mass. Then, with the pressure in the reaction vessel reduced to 0.072 MPa, the stirrer was rotated at 20 Hz, and the vessel was heated to a temperature of 120°C, and a reduced-pressure evaporation operation was carried out. After substantially all of the water contained in the charged raw materials had evaporated, the apparatus was stopped, and the reaction product, a powder that was an aggregate of the fibrous material of Experimental Examples 1 to 6, was removed from the reaction vessel. In all cases, these reaction products were powder-like products having a soft texture, i.e., powders that were aggregates of fibrous material.

[0079] (4) Measurement of moisture content of fibrous materials The moisture content of the fibrous materials (powders that are aggregates of fibrous materials) of Experimental Examples 1 to 6 was measured using an infrared moisture meter (model "FD-720", manufactured by Kett Electric Laboratory Co., Ltd.) under conditions of a drying temperature of 105°C and a drying time of 5 hours. The moisture content of all fibrous materials was 0% (rounded to the nearest integer).

[0080] [2] Preparation of Molded Articles for Modification Evaluation Each of the fibrous materials of Experimental Examples 1 to 6 obtained in [1] above was kneaded with the following polyolefin-based resin (feeding into a twin-screw kneading extruder (manufactured by Technovel Co., Ltd., model "KZW15TW-30 / 45MG-NH", screw diameter 15 mm, L / D = 45) and kneading at an extrusion rate of 0.6 kg / hour and a screw rotation speed of 200 rpm), followed by injection molding to obtain molded articles for evaluation of Experimental Examples 1 to 6. The blending amounts of the fibrous materials are as shown in Table 1. The polyolefin-based resin used was a propylene block copolymer (manufactured by Japan Polypropylene, product name "Novatec BC6", MFR 2.7 g / 10 min, melting point 163°C).

[0081] [3] Evaluation of Molded Articles for Evaluation (1) Measurement of Flexural Modulus Using each of the molded articles for evaluation obtained in [2] above, a tensile test was carried out in accordance with ISO 527-1. The results are shown in Table 1 as "flexural modulus." A molded article for evaluation consisting of only a polyolefin resin (block PP) without any fibrous composite compound 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

[0082] (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 obtained in [2] above. Test pieces with a notch (Type A) were used, and the test was carried out at a test temperature of 23°C by the edgewise test method. The results are shown in Table 1 as "Charpy." Furthermore, an evaluation molded article consisting of only a polyolefin resin (block PP) without any fibrous composite compound 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.

[0083]

[0084] [4] Effects of Examples (1) From the results of Table 1, a graph comparing Experimental Examples 2 and 4 to 6 in which the ratio of water-soluble nonionic compound to cellulosic fiber was 1:10 is shown in Figure 1. It can be seen from Figure 1 that the water-soluble nonionic compound NMP, DMF, DMAc, and DMSO could be dispersed equally easily in the matrix resin, and that the addition of cellulosic fiber significantly improved the flexural modulus.

[0085] Furthermore, when cellulosic fibers are generally blended into a resin for the purpose of modifying the resin, the resulting modified resin has a significantly improved flexural modulus, but a trade-off (a trade-off between flexural modulus and impact resistance) occurs in which the impact resistance is significantly reduced. In this regard, Experimental Examples 2, 4 to 6 maintain high impact resistance (high Charpy impact strength obtained at the same flexural modulus) throughout the entire range of 1900 MPa or less, which is a practical flexural modulus range. In particular, when NMP (Experimental Example 2) or DMF (Experimental Example 4) is used as the water-soluble nonionic compound, it is found that high impact resistance can be maintained compared to when DMAc (Experimental Example 5) or DMSO (Experimental Example 6) is used as the water-soluble nonionic compound. In other words, it is found that the trade-off between flexural modulus and impact resistance can be more effectively suppressed. Furthermore, in FIG. 1, the plotted data for NMP (Experimental Example 2) and the plotted data for DMF (Experimental Example 4) have a flexural modulus of 1513 MPa and a Charpy impact strength of 19.47 kJ / m ２However, it can be seen that in the region of 1513 MPa or less, which can be said to be a more practical range of flexural modulus, Experimental Example 2 can most effectively maintain Charpy impact strength.

[0086] (2) Figure 2 shows a graph comparing Experimental Examples 1 to 3, which are examples using a fibrous material that utilizes NMP, the water-soluble nonionic compound that exhibited the most excellent effect in (1) above, in which the water-soluble nonionic compound:cellulosic fiber ratio was 1:1 to 1:1000. From these results, it can be seen that Experimental Example 3 is most effective in improving the flexural modulus. On the other hand, it can be seen that Experimental Example 1 is most effective in maintaining the Charpy impact strength. In this regard, it can be seen that Experimental Example 2 is most effective in suppressing the trade-off between flexural modulus and impact resistance (it can have the highest Charpy impact strength for the same flexural modulus).

[0087] 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.

[0088] 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 thermoplastic resin composition comprising a thermoplastic resin as a continuous phase and cellulosic fibers dispersed within said continuous phase, characterized in that the modification rate of hydroxy groups possessed by the cellulose constituting said cellulosic fibers is 0.5% or less (including 0%).

2. A thermoplastic resin composition obtained by kneading a thermoplastic resin that forms a continuous phase and a fibrous material that forms a dispersed phase, characterized in that the fibrous material contains cellulosic fibers and a water-soluble nonionic compound with a boiling point above 100°C that is interposed between the cellulosic fibers.

3. The solubility of the water-soluble nonionic compound in water is 0.5 g / 100 gH ２ The thermoplastic resin composition according to claim 2, wherein the molecular weight is 0 or more.

4. A thermoplastic resin composition according to claim 2, wherein the proportion of the water-soluble nonionic compound is 50% by mass or less when the total of the cellulosic fiber and the water-soluble nonionic compound is 100% by mass.

5. The thermoplastic resin composition according to claim 2, wherein the boiling point of said water-soluble nonionic compound is 150°C or higher and 230°C or lower.

6. The thermoplastic resin composition according to claim 2, wherein the water-soluble nonionic compound is at least one of N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide.

7. The thermoplastic resin composition according to claim 1 or 2, wherein the thermoplastic resin is at least one of polyolefin, polyamide and polyester.

8. A method for producing a thermoplastic resin composition, comprising a kneading step of kneading a thermoplastic resin that forms a continuous phase with a fibrous material that forms a dispersed phase, wherein the fibrous material contains cellulosic fibers and a water-soluble nonionic compound with a boiling point of over 100°C that is interposed between the cellulosic fibers.

9. A method for producing a thermoplastic resin composition as described in claim 8, comprising a fibrous material formation step for obtaining the fibrous material, wherein the fibrous material formation step comprises a water removal step for removing water from a mixture in which the cellulosic fiber, the water-soluble nonionic compound, and water coexist.

10. The total amount of the cellulosic fiber and the water-soluble nonionic compound contained in the mixture is 100% by mass, and the ratio of the cellulosic fiber is R Ｃ % by mass, and the proportion of the water-soluble nonionic compound is R Ｗ When expressed as mass%, R Ｃ >R Ｗ The method for producing a thermoplastic resin composition according to claim 9, wherein

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