JP2021066780A - Fibrous substance fluid dispersion, and fiber-reinforced resin composition - Google Patents

Abstract

To provide fibrous substance fluid dispersion which generates extremely small quantity of aggregate in piping and/or a pump, therefore allows for stabilization of a production process and good dispersion of a fibrous substance in a resin, and allows for provision of a resin composition having good and stable physical properties.SOLUTION: A fibrous substance fluid dispersion is provided that includes 100 pts.mass of a dispersion medium and 0.01-20 pts.mass of a fibrous substance dispersed in the dispersion medium. A fluid dispersion for test prepared from the fibrous substance fluid dispersion has a degree α of 80% or less determined according to the following expression (1): α=1-([A]/[B]). In Expression (1), [A] is a height from a bottom surface to a separation interface of the fluid dispersion, and [B] is a height from the bottom surface to an upper surface of the fluid dispersion.SELECTED DRAWING: None

Description

The present invention relates to a fibrous substance dispersion and a resin composition containing the fibrous substance.

Thermoplastic resins are light and have excellent processing characteristics, and are therefore widely used in various fields such as automobile parts, electrical / electronic parts, office equipment housings, and precision parts. However, the resin alone often has insufficient mechanical properties, dimensional stability, and the like, and a composite of the resin and various fibrous substances is generally used.

In recent years, nanofibers such as cellulose nanofibers (CNF) have come to be used as fibrous substances. Since nanofibers such as CNF have the property of agglutinating in a dry state, they are produced as an aqueous dispersion capable of stable dispersion.

Patent Document 1 describes an aqueous dispersion in which a highly viscous hydrophilic cellulose fiber and a thickener are used in combination for the purpose of improving the performance of cosmetics and spray products, and Patent Document 2 describes paper diapers and the like. For the purpose of improving the surface gloss of the molded product recycled from the absorbent article, a thermoplastic resin containing pulp fibers and a highly absorbent polymer is described in Patent Documents 3 and 4, which describes cellulose fibers and a thickener. Examples of the combined use of and in foods and cold insulators are described, respectively.

Japanese Unexamined Patent Publication No. 2014-141675 Japanese Unexamined Patent Publication No. 2016-069543 Japanese Unexamined Patent Publication No. 2013-236585 Japanese Unexamined Patent Publication No. 2014-133826

In recent years, hydrophobic fibers such as hydrophobic modified CNF have come to be used as new fiber reinforcing materials for thermoplastic resins. Since the hydrophobic fiber has a high affinity with the thermoplastic resin, it has high dispersibility in the resin, and is expected to greatly improve mechanical properties and dimensional stability.

Since hydrophobic fibers have the property of agglutinating in a dry state, they are produced as an aqueous dispersion capable of stable dispersion. However, since the hydrophobic fiber does not have a high affinity with water by nature, the hydrophobic fiber dispersion is squeezed in a narrow flow path in the pipe, a gap formed by the reciprocating motion in the pump, etc., and the hydrophobic fiber is squeezed. There is a problem that agglomerates of Since the squeezed agglomerates contain hydrophobic fibers as the main component, water re-permeation hardly occurs, and it is difficult to swell and disperse using water as a medium.

Hydrophobic fiber agglomerates formed by squeezing not only cause problems in the manufacturing process such as pipe clogging and pump clogging, but also due to variations in the composition of the resin composition and mixing of the agglomerates into the resin, the resin composition. It leads to the problem of destabilizing the density and strength of the plastic.

Further, the dispersion liquid containing the hydrophobic fibers has a low water retention property, and has a problem that it dries in a short time as compared with the dispersion liquid of the hydrophilic fibers. As described above, agglomerates of dried hydrophobic fibers are difficult to redisperse in the resin, which leads to poor dispersion in the resin composition and insufficient physical properties due to this.

The techniques described in Patent Documents 1 to 4 do not address the above-mentioned problems concerning the liquid transfer property of the dispersion liquid and the mechanical properties of the resin composition.

The present invention solves the above-mentioned problems peculiar to a slurry containing hydrophobic fibers, and for example, even when hydrophobic fibers are used, the generation of agglomerates in a pipe and / or a pump is extremely small. It is an object of the present invention to provide a fibrous substance dispersion liquid which can stabilize the production process and disperse the fibrous substance in the resin well, and can give a resin composition having good and stable physical characteristics. ..

As a result of diligent studies in order to solve the above-mentioned problems, the present inventor has found that the above-mentioned problems can be solved by controlling the sedimentation of the fibrous substance in the dispersion liquid, and has reached the present invention.
That is, the present invention includes the following aspects.
[1] With 100 parts by mass of the dispersion medium,
0.01 to 20 parts by mass of fibrous material dispersed in the dispersion medium,
It is a fibrous substance dispersion liquid containing
The fibrous substance is a cellulose fiber,
The test dispersion prepared from the fibrous substance dispersion has the following formula (1):
α = 1-([A] / [B]) ... (1)
(In the formula (1), [A] is the height from the bottom surface of the dispersion liquid to the separation interface, and [B] is the height from the bottom surface of the dispersion liquid to the top surface of the dispersion liquid.)
The sedimentation degree α obtained according to the above is 80% or less.
When the concentration of the fibrous substance in the fibrous substance dispersion liquid is 0.05% by mass, the test dispersion liquid is the fibrous substance dispersion liquid itself, and the concentration is 0.05% by mass. If not, the fibrous substance dispersion is prepared by concentrating or diluting the fibrous substance dispersion with the same dispersion medium as the dispersion medium so that the concentration becomes 0.05% by mass.
[2] To 100 parts by mass of the dispersion medium, 0.0001 to 2 parts by mass of a thickener is further contained.
The fibrous substance dispersion liquid according to the above aspect 1, wherein the number average fiber diameter of the fibrous substance is 1 to 1000 nm.
[3] The thickener is one or more selected from the group consisting of polyacrylamide, polyalkylene oxide, polyacrylic acid and its salt, cellulose derivative, polyvinyl alcohol, propylene glycol, alginic acid and its salt. The fibrous substance dispersion liquid according to the second aspect.
[4] The fibrous substance dispersion liquid according to any one of the above aspects 1 to 3, wherein the surface of the fibrous substance is hydrophobic.
[5] The fibrous substance dispersion liquid according to any one of the above aspects 1 to 4, wherein the fibrous substance is cellulose nanofibers.
[6] The above embodiment 5, wherein the cellulose nanofibers have a weight average molecular weight (Mw) of 100,000 or more and a ratio (Mw / Mn) of 6 or less of the weight average molecular weight (Mw) to the number average molecular weight (Mn). Fibrous material dispersion.
[7] The fibrous substance dispersion liquid according to the above aspect 5 or 6, wherein the cellulose nanofibers have an average content of alkali-soluble polysaccharides of 12% by mass or less and a crystallinity of 60% or more.
[8] The fibrous substance dispersion liquid according to any one of the above aspects 5 to 7, wherein the average content of acid-insoluble components of the cellulose nanofibers is 10% by mass or less.
[9] The fibrous substance dispersion liquid according to any one of the above aspects 1 to 8, wherein the dispersion medium is water.
[10] The fibrous substance dispersion liquid according to any one of the above aspects 1 to 9, which contains a particulate component.
[11] The fibrous substance dispersion liquid according to the above aspect 10, which is an emulsion.
[12] The fibrous substance dispersion liquid according to any one of the above aspects 1 to 11, which contains a surfactant.
[13] A method for improving the liquid transfer property of a fibrous substance dispersion liquid containing a dispersion medium and a fibrous substance dispersed in the dispersion medium.
The method is
The test dispersion prepared from the fibrous substance dispersion has the following formula (1):
α = 1-([A] / [B]) ... (1)
(In the formula (1), [A] is the height from the bottom surface of the dispersion liquid to the separation interface, and [B] is the height from the bottom surface of the dispersion liquid to the top surface of the dispersion liquid.)
The fibrous material dispersion liquid contains a thickener so that the sedimentation degree α obtained according to the above is 80% or less.
When the concentration of the fibrous substance in the fibrous substance dispersion liquid is 0.05% by mass, the test dispersion liquid is the fibrous substance dispersion liquid itself, and the concentration is 0.05% by mass. If not, the method is prepared by concentrating the fibrous substance dispersion liquid or diluting it with the same dispersion medium as the dispersion medium so that the concentration becomes 0.05% by mass.
[14] A resin composition containing 100 parts by mass of a resin, 0.001 to 50 parts by mass of a fibrous substance having an average fiber diameter of 1 to 1000 nm, and 0.00001 to 5 parts by mass of a thickener.
[15] The resin composition according to the above aspect 14, wherein the resin is a thermoplastic resin.
[16] The tensile yield elongation (TEy) and the tensile elongation at break (TEb) are the following relational expressions:
[TEb / TEy] ≧ 1
The resin composition according to the above aspect 14 or 15, which satisfies the above conditions.
[17] The resin composition according to any one of the above aspects 14 to 16, wherein the tensile strength is improved by 1.01 times or more as compared with the comparative resin composition having the same composition except that the thickener is not contained. Stuff.
[18] A method for producing a resin composition containing a thermoplastic resin and a fibrous substance.
To prepare the fibrous substance dispersion according to any one of the above aspects 1 to 12,
Melting and kneading the fibrous material dispersion and the thermoplastic resin,
Including methods.
[19] A method for producing a resin composition containing a thermoplastic resin and a fibrous substance.
To prepare the fibrous substance dispersion according to any one of the above aspects 1 to 12,
To prepare a dried product by drying the fibrous substance dispersion liquid,
Melting and kneading the dried product and the thermoplastic resin,
Including methods.

According to one aspect of the present invention, for example, even when hydrophobic fibers are used, the generation of agglomerates in piping and / or pumps is extremely small, so that the production process is stabilized and the resin is used. It is possible to provide a fibrous substance dispersion liquid which can disperse the fibrous substance well and can give a resin composition having good and stable physical properties.

It is explanatory drawing of the calculation method of IR index 1730 and IR index 1030. It is explanatory drawing of the calculation method of the average degree of substitution of the hydroxyl group of cellulose.

Hereinafter, embodiments of the present invention will be specifically described, but the present invention is not limited to these aspects.

≪Fibrous substance dispersion liquid≫
One aspect of the present invention provides a fibrous substance dispersion liquid (also simply referred to as a dispersion liquid in the present disclosure) containing a dispersion medium and a fibrous substance dispersed in the dispersion medium. In one embodiment, the fibrous material is a cellulose fiber. In one embodiment, the amount of fibrous material in the dispersion is 0.01 to 20 parts by mass with respect to 100 parts by mass of the dispersion medium.

In one embodiment, the test dispersion prepared from the fibrous material dispersion has the following formula (1):
α = 1-([A] / [B]) ... (1)
(In the formula (1), [A] is the height from the bottom surface of the dispersion liquid to the separation interface, and [B] is the height from the bottom surface of the dispersion liquid to the top surface of the dispersion liquid.)
The sedimentation degree α obtained according to the above is 80% or less. Here, the test dispersion liquid is the fibrous substance dispersion liquid itself when the concentration of the fibrous substance in the fibrous substance dispersion liquid is 0.05% by mass, and the concentration is 0.05% by mass. If not, the fibrous substance dispersion is concentrated or diluted with the same (that is, the same substance) dispersion as the dispersion in the dispersion so that the concentration is 0.05% by mass. There is. Dilution is performed by adding a required amount of a dispersion medium to the dispersion liquid. Concentration is performed by separating the dispersion liquid into a dispersion medium and a fibrous substance by a filter cloth, a membrane filter, centrifugation or the like. After dividing 20 ml of the test dispersion into a glass vial having a capacity of 30 ml, disperse it with a homogenizer (rotation speed: 10000 rpm, 1 minute), and then quickly add 8 ml of the test dispersion to a 15 ml capacity screw cap test tube (AS ONE part number: 4). It is placed in −565-06), sealed, and shaken manually to homogenize the dispersion, and then allowed to stand at a temperature of 23 ° C. and normal pressure for 24 hours. The separation interface is defined by an in-liquid dispersion stability evaluation device (for example, "Turbiscan" manufactured by FORMULICION), and [A] and [B] are measured.

The sedimentation degree α of the present disclosure is an index of the dispersion stability (difficulty of sedimentation in the dispersion medium) of the fibrous substance of the dispersion liquid, and the smaller the value, the more difficult it is to settle (that is, the fibrous substance of the dispersion medium). (It is unlikely that separation and exudation will occur over time). Since the dispersion liquid of the present disclosure can have various fibrous substance concentrations, the sedimentation degree α is measured after adjusting the fibrous substance concentration to 0.05% by mass. The sedimentation degree α is 80% or less, preferably 70% or less, 60% or less, or 50% or less from the viewpoint of good dispersibility of the fibrous material. From the viewpoint of ease of preparation of the dispersion liquid, the sedimentation degree α may be 1% or more, 5% or more, or 10% or more. As a method of controlling the sedimentation degree α of the dispersion liquid of the present disclosure within the above range, control of the shape of the fibrous substance (for example, a method of giving unevenness, fluff, etc. to the surface of the fibrous substance), various additives (for example, Use of thickener) and the like.

<Fibrous material>
Examples of the fibrous substance include cellulose fibers, synthetic polymer fibers, glass fibers, carbon fibers and the like. In one aspect, the fibrous material is cellulose fibers, especially cellulose nanofibers. Cellulose nanofibers are made by treating pulp or the like with hot water at 100 ° C. or higher, hydrolyzing hemicellulose to make it fragile, and then using a high-pressure homogenizer, microfluidizer, ball mill, disc mill, mixer (for example, homomixer), etc. Refers to cellulose deflated by the crushing method of. The cellulose fiber may be chemically modified as described below.

In one aspect, the number average fiber diameter of the fibrous material is preferably 1 to 1000 nm from the viewpoint of satisfactorily obtaining the effect of improving the physical properties of the fibrous material. The number average fiber diameter of the fibrous material is more preferably 4 nm or more, more preferably 5 nm or more, more preferably 10 nm or more, more preferably 15 nm or more, still more preferably 20 nm or more, still more preferably 500 nm or less. It is more preferably 450 nm or less, more preferably 400 nm or less, more preferably 350 nm or less, still more preferably 300 nm or less, still more preferably 250 nm or less.
It is particularly preferable that the fibrous substance is a cellulose nanofiber having the above number average fiber diameter.

The lower limit of the average L / D of the fibrous material (preferably cellulose nanofibers) is preferably 50, more preferably 80, more preferably 100, even more preferably 120, and most preferably 120. It is 150. The upper limit is not particularly limited, but is preferably 5000 or less from the viewpoint of handleability. From the viewpoint of improving the mechanical properties of the resin composition containing the fibrous substance with a small amount of the fibrous substance, it is desirable that the average L / D ratio of the fibrous substance is within the above range.

In the present disclosure, the length, diameter, and L / D ratio of each of the fibrous substances are 0.01 to 0.01 to the aqueous dispersion of the fibrous substances in a water-soluble solvent (for example, water, ethanol, tert-butanol, etc.). Dilute to 0.1% by mass, use a high-shear homogenizer (for example, manufactured by IKA, trade name "Ultratalax T18"), and disperse under treatment conditions: rotation speed 25,000 rpm x 5 minutes, cast on mica, and cast. The air-dried sample is used as a measurement sample and measured with a high-resolution scanning electron microscope (SEM) or an atomic force microscope (AFM). Specifically, the length (L) and diameter (D) of 100 fibrous substances randomly selected in the observation field of view adjusted so that at least 100 fibrous substances can be observed. Is measured and the ratio (L / D) is calculated. For the fibrous material, the number average value of the length (L), the number average value of the diameter (D), and the number average value of the ratio (L / D) are calculated.

The length, diameter, and L / D ratio of the fibrous substance in the composition described later can be confirmed by measuring the solid composition as a measurement sample by the above-mentioned measuring method. Alternatively, the length, diameter, and L / D ratio of the fibrous substance in the composition are determined by dissolving the resin component in the composition in an organic or inorganic solvent capable of dissolving the resin component of the composition to obtain the fibrous substance. After separation and thorough washing with the above solvent, an aqueous dispersion prepared by substituting the solvent with pure water was prepared, and the fibrous substance concentration was diluted with pure water to 0.1 to 0.5% by mass on mica. It can be confirmed by casting to and air-drying as a measurement sample and measuring by the above-mentioned measuring method. At this time, 100 or more randomly selected fibrous substances are measured.

When the fibrous substance is a cellulose fiber, the crystallinity of the cellulose fiber is preferably 55% or more. When the crystallinity is in this range, the mechanical properties (strength and dimensional stability) of the cellulose fiber itself are high. Therefore, when the cellulose fiber is dispersed in the resin, the strength and dimensional stability of the resin composition tend to be high. is there. The lower limit of the more preferable crystallinity is 60%, even more preferably 70%, and most preferably 80%. The upper limit of the crystallinity of the cellulose fiber is not particularly limited, and a higher value is preferable, but a preferable upper limit is 99% from the viewpoint of production.

Alkali-soluble polysaccharides such as hemicellulose and acid-insoluble components such as lignin are present between microfibrils of plant-derived cellulose and between microfibril bundles. Hemicellulose is a polysaccharide composed of sugars such as mannan and xylan, and plays a role of hydrogen bonding with cellulose to connect microfibrils. Lignin is a compound having an aromatic ring, and is known to be covalently bound to hemicellulose in the cell wall of plants. If the residual amount of impurities such as lignin in the cellulose fiber is large, discoloration may occur due to heat during processing. Therefore, from the viewpoint of suppressing discoloration of the resin composition during extrusion processing and molding processing, the cellulose fiber It is desirable that the degree of crystallinity of is within the above range.

The degree of crystallinity referred to here is based on the diffraction pattern (2θ / deg. 10 to 30) when the sample is measured by wide-angle X-ray diffraction when the cellulose fiber is a cellulose type I crystal (derived from natural cellulose). It is calculated by the following formula by the Segal method.
Crystallinity (%) = ([Diffraction intensity due to (200) plane of 2θ / deg. = 22.5]-[Diffraction intensity due to amorphous of 2θ / deg. = 18]) / [2θ / Deg. = Diffraction intensity due to 22.5 (200) plane] × 100

The degree of crystallinity is 2θ = 12.6 °, which is assigned to the (110) plane peak of the cellulose type II crystal in wide-angle X-ray diffraction when the cellulose fiber is a cellulose type II crystal (derived from regenerated cellulose). From the absolute peak intensity h0 in, and the peak intensity h1 from the baseline at this surface spacing, it is calculated by the following equation.
Crystallinity (%) = h1 / h0 x 100

As the crystal form of cellulose, type I, type II, type III, type IV and the like are known, and among them, type I and type II are widely used, and type III and type IV are obtained on a laboratory scale. Although it has been used, it is not widely used on an industrial scale. The cellulose fibers (cellulose nanofibers in one embodiment) of the present disclosure have relatively high structural mobility, and by dispersing the cellulose fibers in a resin, the linear expansion coefficient is lower, and the cellulose fibers are pulled and bent and deformed. Since a resin composition having more excellent strength and elongation can be obtained, cellulose fibers containing cellulose type I crystals or cellulose type II crystals are preferable, and cellulose type I crystals are contained and the degree of crystallization is 55% or more. Cellulose fibers are more preferred.

The degree of polymerization of the cellulose fiber is preferably 100 or more, more preferably 150 or more, more preferably 200 or more, more preferably 300 or more, preferably 400 or more, more preferably 420 or more, and more preferably 430 or more. , More preferably 440 or more, more preferably 450 or more, preferably 3500 or less, more preferably 3300 or less, more preferably 3200 or less, more preferably 3100 or less, still more preferably 3000 or less.

From the viewpoint of processability and expression of mechanical properties, it is desirable that the degree of polymerization of the cellulose fiber is within the above range. From the viewpoint of processability, it is preferable that the degree of polymerization is not too high, and from the viewpoint of developing mechanical properties, it is desirable that the degree of polymerization is not too low.

The degree of polymerization of cellulose fibers means the average degree of polymerization measured according to the reduction specific viscosity method with a copper ethylenediamine solution described in the confirmation test (3) of the "15th revised Japanese Pharmacopoeia Manual (published by Hirokawa Shoten)". ..

In one embodiment, the weight average molecular weight (Mw) of the cellulose fibers is 100,000 or more, more preferably 200,000 or more. The ratio (Mw / Mn) of the weight average molecular weight to the number average molecular weight (Mn) is 6 or less, preferably 5.4 or less. The larger the weight average molecular weight, the smaller the number of terminal groups of the cellulose molecule. Further, since the ratio (Mw / Mn) of the weight average molecular weight to the number average molecular weight represents the width of the molecular weight distribution, it means that the smaller the Mw / Mn, the smaller the number of terminals of the cellulose molecule. Since the end of the cellulose molecule is the starting point of thermal decomposition, not only the weight average molecular weight of the cellulose molecule of the cellulose fiber is large, but also when the weight average molecular weight is large and the width of the molecular weight distribution is narrow, the cellulose having high heat resistance is particularly high. A resin composition containing fibers and cellulose fibers and a resin can be obtained. The weight average molecular weight (Mw) of the cellulose fibers may be, for example, 600,000 or less, or 500,000 or less, from the viewpoint of availability of the cellulose raw material. The ratio (Mw / Mn) of the weight average molecular weight to the number average molecular weight (Mn) may be, for example, 1.5 or more, or 2 or more, from the viewpoint of ease of producing cellulose fibers. The Mw can be controlled within the above range by selecting a cellulose raw material having Mw according to the purpose, appropriately performing physical treatment and / or chemical treatment on the cellulose raw material within an appropriate range, and the like. Mw / Mn also has the above range by selecting a cellulose raw material having Mw / Mn according to the purpose, appropriately performing physical treatment and / or chemical treatment on the cellulose raw material within an appropriate range, and the like. Can be controlled. In both Mw control and Mw / Mn control, the physical treatment includes dry or wet pulverization of a microfluidizer, ball mill, disc mill, etc., grinder, homomixer, high-pressure homogenizer, ultrasonic device. Physical treatments that apply mechanical forces such as impact, shearing, shearing, and friction due to such factors can be exemplified, and examples of the chemical treatments include cooking, bleaching, acid treatment, and regenerated cellulose formation.

The weight average molecular weight and number average molecular weight of cellulose referred to here are those obtained by dissolving cellulose in N, N-dimethylacetamide to which lithium chloride is added, and then gel permeation chromatography using N, N-dimethylacetamide as a solvent. This is the calculated value.

Examples of the method for controlling the degree of polymerization (that is, the average degree of polymerization) or the molecular weight of the cellulose fibers include hydrolysis treatment and the like. By the hydrolysis treatment, the amorphous cellulose inside the cellulose fiber is depolymerized, and the average degree of polymerization is reduced. At the same time, the hydrolysis treatment removes impurities such as hemicellulose and lignin in addition to the above-mentioned amorphous cellulose, so that the inside of the fiber becomes porous.

The method of hydrolysis is not particularly limited, and examples thereof include acid hydrolysis, alkali hydrolysis, hydrothermal decomposition, steam explosion, and microwave decomposition. These methods may be used alone or in combination of two or more. In the acid hydrolysis method, for example, α-cellulose obtained as pulp from a fibrous plant is used as a cellulose raw material, and in a state where this is dispersed in an aqueous medium, an appropriate amount of protonic acid, carboxylic acid, Lewis acid, heteropolyacid, etc. is added. In addition, the average degree of polymerization can be easily controlled by heating while stirring. The reaction conditions such as temperature, pressure, and time at this time differ depending on the cellulose type, cellulose concentration, acid type, acid concentration, etc., but are appropriately prepared so as to achieve the desired average degree of polymerization. For example, there is a condition that cellulose is treated for 10 minutes or more under pressure at 100 ° C. or higher using an aqueous mineral acid solution of 2% by mass or less. Under this condition, the catalyst component such as acid permeates into the inside of the cellulose fiber, hydrolysis is promoted, the amount of the catalyst component used is reduced, and the subsequent purification is facilitated. The dispersion liquid of the cellulose raw material at the time of hydrolysis may contain a small amount of an organic solvent in addition to water as long as the effect of the present invention is not impaired.

Alkali-soluble polysaccharides that can be contained in cellulose fibers include β-cellulose and γ-cellulose as well as hemicellulose. The alkali-soluble polysaccharide is a component (that is, a component obtained by removing α-cellulose from holocellulose) obtained as an alkali-soluble portion of holocellulose obtained by solvent-extracting and chlorine-treating a plant (for example, wood). Understood by those skilled in the art. Alkali-soluble polysaccharides are polysaccharides containing hydroxyl groups and have poor heat resistance, and are inconvenient because they decompose when heated, cause yellowing during heat aging, and cause a decrease in the strength of cellulose fibers. Therefore, it is preferable that the content of the alkali-soluble polysaccharide in the cellulose fiber is small.

In one aspect, the average content of alkali-soluble polysaccharides in the cellulose fibers is preferably 20% by mass or less, or 18% by mass, based on 100% by mass of the cellulose fibers, from the viewpoint of obtaining good dispersibility of the cellulose fibers. % Or less, or 15% by mass or less, or 12% by mass or less. The content may be 1% by mass or more, 2% by mass or more, or 3% by mass or more from the viewpoint of ease of production of cellulose fibers.

The average content of alkali-soluble polysaccharides can be determined by the method described in non-patent documents (Wood Science Experiment Manual, edited by Japan Wood Society, pp. 92-97, 2000), and the holocellulose content (Wise method). It is obtained by subtracting the α-cellulose content from. This method is understood in the art as a method for measuring the amount of hemicellulose. The alkali-soluble polysaccharide content is calculated three times for one sample, and the number average of the calculated alkali-soluble polysaccharide content is defined as the alkali-soluble polysaccharide average content.

In one embodiment, the average content of the acid-insoluble component in the cellulose fiber is preferably 10% by mass or less, or 10% by mass or less, based on 100% by mass of the cellulose fiber, from the viewpoint of avoiding a decrease in heat resistance of the cellulose fiber and the accompanying discoloration. It is 5% by mass or less, or 3% by mass or less. The content may be 0.1% by mass or more, 0.2% by mass or more, or 0.3% by mass or more from the viewpoint of ease of production of cellulose fibers.

The average content of acid-insoluble components is determined as a quantification of acid-insoluble components using the Clarson method described in a non-patent document (Wood Science Experiment Manual, edited by Japan Wood Society, pp. 92-97, 2000). This method is understood in the art as a method for measuring the amount of lignin. The sample is stirred in a sulfuric acid solution to dissolve cellulose, hemicellulose, etc., and then filtered through a glass fiber filter paper, and the obtained residue corresponds to an acid-insoluble component. The acid-insoluble component content is calculated from the weight of the acid-insoluble component, and the number average of the acid-insoluble component contents calculated for the three samples is defined as the acid-insoluble component average content.

Cellulose fibers may be chemically treated (for example, oxidized or chemically modified with a modifying agent). As an example, after oxidizing cellulose fibers with 2,2,6,6-tetramethylpiperidin-1-oxyl radicals as shown in Cellulose (1998) 5,153-164, washing and mechanical defibration are performed. Finely divided cellulose fibers obtained by passing through may be used.

As the modifying agent for cellulose, a compound that reacts with the hydroxyl group of cellulose can be used, and examples thereof include an esterifying agent, an etherizing agent, and a silylating agent. In a preferred embodiment, the chemical modification is acylation with an esterifying agent. As the esterifying agent, acid halides, acid anhydrides, and carboxylic acid vinyl esters are preferable.

The acid halide may be at least one selected from the group consisting of the compounds represented by the following formula (1).
R ^1- C (= O) -X (1)
(In the formula, R ¹ represents an alkyl group having 1 to 24 carbon atoms, an alkenyl group having 2 to 24 carbon atoms, a cycloalkyl group having 3 to 24 carbon atoms, or an aryl group having 6 to 24 carbon atoms, and X is Cl. , Br or I.)
Specific examples of acid halides include acetyl chloride, acetyl bromide, acetyl iodide, propionyl chloride, propionyl bromide, propionyl iodide, butyryl chloride, butyryl bromide, butyryl iodide, benzoyl chloride, benzoyl bromide, and iodide. Examples include, but are not limited to, benzoyl chloride. Among them, the acid chloride can be preferably adopted from the viewpoint of reactivity and handleability. In the reaction of the acid halide, one or more alkaline compounds may be added for the purpose of neutralizing an acidic substance which is a by-product at the same time as acting as a catalyst. Specific examples of the alkaline compound include, but are not limited to, tertiary amine compounds such as triethylamine and trimethylamine; and nitrogen-containing aromatic compounds such as pyridine and dimethylaminopyridine.

As the acid anhydride, any suitable acid anhydride can be used. For example
Saturated aliphatic monocarboxylic acid anhydrides such as acetic acid, propionic acid, (iso) butyric acid and valeric acid; unsaturated aliphatic monocarboxylic acid anhydrides such as (meth) acrylic acid and oleic acid;
Alicyclic monocarboxylic acid anhydrides such as cyclohexanecarboxylic acid and tetrahydrobenzoic acid;
Aromatic monocarboxylic acid anhydrides such as benzoic acid and 4-methylbenzoic acid;
Examples of the dibasic carboxylic acid anhydride include an anhydride-saturated aliphatic dicarboxylic acid such as succinic anhydride and adipic acid, anhydrous unsaturated aliphatic dicarboxylic acid anhydride such as maleic anhydride and itaconic anhydride, and 1-cyclohexene anhydride-1. , 2-Dicarboxylic acid, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride and other anhydrous alicyclic dicarboxylic acids, and anhydrous phthalic acid, naphthalic anhydride and other anhydrous aromatic dicarboxylic acid anhydrides, etc.;
Examples of polybasic carboxylic acid anhydrides having 3 or more bases include (anhydrous) polycarboxylic acids such as trimellitic anhydride and pyromellitic anhydride.
In the reaction of acid anhydride, one or more acidic compounds such as sulfuric acid, hydrochloric acid and phosphoric acid, Lewis acids such as metal chloride and metal triflate, and alkaline compounds such as triethylamine and pyridine are used as catalysts. It may be added.

The carboxylic acid vinyl ester has the following formula (1):
R-COO-CH = CH ₂ ... Equation (1)
{In the formula, R is either an alkyl group having 1 to 24 carbon atoms, an alkenyl group having 2 to 24 carbon atoms, a cycloalkyl group having 3 to 16 carbon atoms, or an aryl group having 6 to 24 carbon atoms. } Is preferred. Vinyl carboxylic acid esters include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl caproate, vinyl cyclohexanecarboxylate, vinyl caprilate, vinyl caproate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, and pivalin. More preferably, it is at least one selected from the group consisting of vinyl acetate, vinyl octylate divinyl adipate, vinyl methacrylate, vinyl crotonic acid, vinyl pivalate, vinyl octylate, vinyl benzoate, and vinyl cinnamic acid. .. In the esterification reaction with vinyl carboxylate ester, as a catalyst, alkali metal hydroxide, alkaline earth metal hydroxide, alkali metal carbonate, alkaline earth metal carbonate, alkali metal hydrogen carbonate, grades 1 to 3. One or more selected from the group consisting of amines, quaternary ammonium salts, imidazoles and derivatives thereof, pyridines and derivatives thereof, and alkoxides may be added.

Examples of the alkali metal hydroxide and alkaline earth metal hydroxide include sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, barium hydroxide and the like. Alkali metal carbonates, alkaline earth metal carbonates, alkali metal bicarbonates include lithium carbonate, sodium carbonate, potassium carbonate, cesium carbonate, magnesium carbonate, calcium carbonate, barium carbonate, lithium hydrogen carbonate, sodium hydrogen carbonate, carbonic acid. Examples include potassium hydrogen hydrogen and cesium hydrogen carbonate.

The 1st to 3rd amines are primary amines, secondary amines, and tertiary amines, and specific examples thereof include ethylenediamine, diethylamine, proline, N, N, N', and N'-tetramethylethylenediamine. N, N, N', N'-tetramethyl-1,3-propanediamine, N, N, N', N'-tetramethyl-1,6-hexanediamine, tris (3-dimethylaminopropyl) amine, Examples thereof include N, N-dimethylcyclohexylamine and triethylamine.

Examples of imidazole and its derivatives include 1-methylimidazole, 3-aminopropylimidazole, carbonyldiimidazole and the like.

Examples of pyridine and its derivatives include N, N-dimethyl-4-aminopyridine, picoline and the like.

Examples of the alkoxide include sodium methoxide, sodium ethoxide, potassium-t-butoxide and the like.

Among these esterification reactants, at least one selected from the group consisting of acetic anhydride, propionic anhydride, butyric anhydride, vinyl acetate, vinyl propionate, and vinyl butyrate, among which acetic anhydride and vinyl acetate have reaction efficiencies. It is preferable from the viewpoint of.

The degree of modification of the chemically modified cellulose fiber of the present embodiment is expressed as the average degree of substitution of hydroxyl groups (the average number of substituted hydroxyl groups per glucose, which is the basic constituent unit of cellulose, also referred to as DS). In one embodiment, the DS of the chemically modified cellulose fiber is preferably 0.01 or more and 2.0 or less. When the DS is 0.01 or more, a resin composition containing chemically modified cellulose having a high thermal decomposition start temperature can be obtained. On the other hand, when it is 2.0 or less, an unmodified cellulose skeleton remains in the chemically modified cellulose, so that the chemical modification has both high tensile strength and dimensional stability derived from cellulose and a high thermal decomposition start temperature derived from the chemical modification. A resin composition containing cellulose can be obtained. The DS is more preferably 0.05 or more, still more preferably 0.1 or more, particularly preferably 0.2 or more, most preferably 0.3 or more, still more preferably 1.8 or less, still more preferably 1. It is 5 or less, particularly preferably 1.2 or less, and most preferably 1.0 or less.

When the modifying group of the chemically modified cellulose fiber is an acyl group, the degree of acyl substitution (DS) is the peak intensity ratio between the peak derived from the acyl group and the peak derived from the cellulose skeleton from the reflective infrared absorption spectrum of the esterified cellulose fiber. Can be calculated based on. The peak of the C = O absorption band based on the acyl group ^{appears at 1730 cm -1,} and the peak of the CO-O absorption band based on the cellulose skeleton chain appears at 1030 cm ^-1 (see FIGS. 1 and 2). The DS of the esterified cellulose fiber is the DS obtained from the solid-state NMR measurement of the esterified cellulose fiber described later, and the peak intensity of the absorption band of C = O based on the acyl group with respect to the peak intensity of the absorption band of the cellulose skeleton chain CO. A correlation graph with the modification rate (IR index 1030) defined by the ratio of is prepared, and the calibration curve substitution degree DS = 4.13 × IR index (1030) calculated from the correlation graph.
Can be obtained by using.

The method for calculating the DS of the esterified cellulose fiber by solid-state NMR is that ¹³ C solid-state NMR measurement is performed on the freeze-ground esterified cellulose fiber, and it is attributed to carbon C1-C6 derived from the pyranose ring of cellulose appearing in the range of 50 ppm to 110 ppm. It can be obtained by the following formula from the area intensity (Inf) of the signal assigned to one carbon atom derived from the modifying group with respect to the total area intensity (Inp) of the signal.
DS = (Inf) x 6 / (Inp)
For example, if the modifying group is an acetyl group, a 23 ppm signal attributed to _{−CH 3 may be used.}
^{The conditions for the 13} C solid-state NMR measurement used are as follows, for example.
Equipment: Bruker Biospin Avance 500WB
Frequency: 125.77MHz
Measurement method: DD / MAS method Waiting time: 75 sec
NMR sample tube: 4 mmφ
Accumulation number: 640 times (about 14 hours)
MAS: 14,500Hz
Chemical shift standard: Glycine (external standard: 176.03 ppm)

The DS non-uniform ratio (DSt) defined by the ratio of the degree of modification (DSs) on the fiber surface to the degree of modification (DSt) of the entire fiber of the chemically modified cellulose fiber (which is synonymous with the above-mentioned degree of acyl substitution (DS)). DSs / DSt) is preferably 1.05 or more. The larger the value of the DS non-uniform ratio, the more non-uniform structure like the sheath core structure (that is, the fiber surface layer is highly chemically modified while the fiber center retains the structure of cellulose which is close to the original unmodified structure. (Structure) is remarkable, and while having high tensile strength and dimensional stability derived from cellulose, it is possible to improve the affinity with the resin at the time of compounding with the resin and the dimensional stability of the resin composition. is there. The DS non-uniform ratio is more preferably 1.1 or more, 1.2 or more, 1.3 or more, 1.5 or more, or 2.0, from the viewpoint of ease of production of chemically modified cellulose fibers. Therefore, it is preferably 30 or less, or 20 or less, or 10 or less, or 6 or less, or 4 or less, or 3 or less.
The value of DSs varies depending on the degree of modification of the esterified cellulose, but as an example, it is preferably 0.1 or more, more preferably 0.2 or more, still more preferably 0.3 or more, still more preferably 0.5 or more. It is preferably 3.0 or less, more preferably 2.5 or less, particularly preferably 2.0 or less, still more preferably 1.5 or less, particularly preferably 1.2 or less, and most preferably 1.0 or less. is there. The preferred range of DSt is as described above for acyl substituents (DS).

The smaller the coefficient of variation (CV) of the DS non-uniform ratio of the chemically modified cellulose fiber is, the smaller the variation in various physical properties of the resin composition is, which is preferable. The coefficient of variation is preferably 50% or less, or 40% or less, or 30% or less, or 20% or less. The above fluctuation coefficient can be further reduced by, for example, a method of obtaining chemically modified cellulose fibers by chemically modifying the cellulose raw material after defibrating it (that is, a sequential method), while defibrating and chemically modifying the cellulose raw material at the same time. The method (ie, simultaneous method) can be increased. Although the mechanism of action has not been clarified, it is understood that the simultaneous method makes it easier for chemical modification to proceed in the fine fibers produced in the early stage of defibration, and that the chemical modification reduces hydrogen bonds between cellulose microfibrils. As a result of the further progress of the fibers, it is considered that the coefficient of variation of the DS non-uniformity ratio increases.

For the coefficient of variation (CV) of the DS non-uniform ratio, 100 g of an aqueous dispersion of chemically modified cellulose fibers (solid content of 10% by mass or more) was sampled, and 10 g of each was freeze-ground and used as a measurement sample. After calculating the DS non-uniform ratio from the DSs, it can be calculated by the following formula from the standard deviation (σ) and the arithmetic mean (μ) of the DS non-uniform ratio among the obtained 10 samples.
DS non-uniform ratio = DSs / DSt
Coefficient of variation (%) = standard deviation σ / arithmetic mean μ × 100

The calculation method of DSs is as follows. That is, the esterified cellulose powdered by freeze pulverization is placed on a dish-shaped sample table having a diameter of 2.5 mm, the surface is suppressed and flattened, and measurement is performed by X-ray photoelectron spectroscopy (XPS). The XPS spectrum reflects the constituent elements and the chemical bond state of only the surface layer of the sample (typically about several nm). Peak separation was performed on the obtained C1s spectrum, and the peak (289eV, CC bond) attributed to carbon C2-C6 derived from the pyranose ring of cellulose was assigned to one carbon atom derived from the modifying group with respect to the area intensity (Ipp). It can be calculated by the following formula from the area intensity (Ixf) of the peak to be formed.
DSs = (Ixf) x 5 / (Ixp)
For example, when the modifying group is an acetyl group, the C1s spectrum is peak-separated at 285 eV, 286 eV, 288 eV, and 289 eV, and then the peak of 289 ev is used for Ix and the O-C = O bond of the acetyl group is used for Ixf. A peak (286 eV) may be used.
The conditions for XPS measurement used are as follows, for example.
Equipment used: ULVAC-PHI VersaProbeII
Excitation source: mono. AlKα 15kV x 3.33mA
Analysis size: Approximately 200 μmφ
Photoelectron extraction angle: 45 °
Capture area Now scan: C 1s, O 1s
Pass Energy: 23.5eV

In one embodiment, the fibrous material is a synthetic polymeric fiber. Examples of the synthetic polymer fiber include polyamide (for example, polyamide 66) fiber, aramid fiber, Kevlar, polypropylene fiber, polyester fiber, polyurethane fiber, and nanofiber obtained by further defibrating these by a defibration method described later.

Examples of the method for producing the synthetic polymer fiber include a melt spinning method, a wet spinning method, an electric field spinning method, a carbon dioxide laser supersonic stretching method, a high-pressure homogenizer defibration, and an underwater opposed collision method. Synthetic polymer fibers may be produced by using one or a plurality of these methods in combination.

A plurality of types of fibrous substances may be used in combination. Further, the fibrous substance may be surface-treated with a surface modifier, a surfactant or the like.

In one aspect, the fibrous material is hydrophobic. Hydrophobicity in the present disclosure refers to a state in which the hydrophilicity of a molecule is lowered by a low-polarity or non-polar functional group. Specific examples of hydrophobic fibrous substances include aramid fibers. When the fibrous substance is cellulose fiber (cellulose nanofiber in one embodiment), cellulose itself is a highly hydrophilic substance, but the hydroxyl group of cellulose is acetylated, propionylated, or butylated by the method as described above. , A hydrophobic fibrous substance can be obtained by esterification by a method such as benzylation or adamantylation.

<Dispersion medium>
As the dispersion medium of the fibrous substance dispersion liquid, a liquid medium such as water or an organic solvent can be used. As the organic solvent, a commonly used water-miscible organic solvent can be used. As the water-miscible organic solvent, polyols (for example, polypropylene glycol, polyether polyols such as polyethylene glycol, etc.), ethanol, methanol, dimethylformamide, dimethylsulfoxide, acetonitrile, acetone, acetic acid, t-butanol and the like can be used. Water is particularly preferable from the viewpoint of handleability. In one embodiment, the dispersion medium in the dispersion is water.

<Thickener>
The thickener is not particularly limited as long as it can increase the viscosity of the dispersion medium and stabilize the fibrous substance dispersion liquid. Stabilization here includes improvement of phase separability of the fibrous material dispersion (that is, increase of affinity between the fibrous material and the dispersion medium), suppression of aggregation of the fibrous material, improvement of liquid permeability, etc. Can be mentioned.

The amount of the thickener with respect to 100 parts by mass of the dispersion medium is preferably 0.0001 parts by mass or more, more preferably 0.001 parts by mass or more, still more preferably 0.005 parts by mass, from the viewpoint of obtaining a good thickening effect. From the viewpoint of avoiding the inconvenience caused by the residual thickener in the resin composition when the resin composition is produced using the dispersion liquid, it is preferably 2 parts by mass or less, more preferably 1.5 parts by mass. It is less than a part, more preferably 1 part by mass or less.

As the thickener, polymers having a hydrophilic group (for example, hydroxyl group, amino group, etc.) (for example, polyacrylamide, polyalkylene oxide, polyacrylic acid and salts thereof, polysaccharides (for example, cellulose derivative, starch, alginic acid, etc.) and Examples thereof include salts thereof (for example, sodium alginate), guar gum, gellan gum, gelatin, etc., polyvinyl alcohol, etc., and monomers having a hydrophilic group (for example, propylene glycol, N-vinylacetamide, etc.). These have a good thickening effect in a dispersion medium (a dispersion medium containing water in one embodiment) and contribute to good dispersion of fibrous substances. Among them, one or more selected from the group consisting of polyacrylamide, polyalkylene oxide, polyacrylic acid and salts thereof, cellulose derivatives, polyvinyl alcohol, alginic acid and salts thereof is preferable.

Examples of the alkylene oxide unit of the polyalkylene oxide include alkylene oxides having 2 to 4 carbon atoms, preferably ethylene oxide and propylene oxide. In a preferred embodiment, the polyalkylene oxide is composed of ethylene oxide units and / or propylene oxide units. A particularly preferred polyalkylene oxide is polyethylene oxide.

Examples of the cellulose derivative include cellulose ethers (for example, methyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, etc.).

The weight average molecular weight of the thickener is preferably 1,000 or more, more preferably 5,000 or more, still more preferably 10000 or more, preferably 5 × 10 ⁸ or less, more preferably 10 ⁸ or less, more preferably 5 × 10 ⁷ It is as follows.

In one aspect, the thickener is a surfactant. Surfactants have a chemical structure in which a site having a hydrophilic substituent and a site having a hydrophobic substituent are covalently bonded. As the surfactant, any of anionic surfactant, nonionic surfactant, amphoteric ionic surfactant, and cationic surfactant can be used, but a dispersion liquid of a fibrous substance can be used. Nonionic surfactants are preferred because they can better reduce sedimentation in them.

As the hydrophilic group of the surfactant, a polyoxyethylene chain, a carboxyl group, and a hydroxyl group are preferable, and a polyoxyethylene chain is particularly preferable, in terms of affinity with a fibrous substance (particularly cellulose fiber). Nonionic polyoxyethylene derivatives are particularly preferred. The polyoxyethylene chain length of the polyoxyethylene derivative may be 1 or more, 4 or more, 10 or more, or 15 or more. The longer the chain length, the higher the affinity with the hydrophobic fibrous substance. However, from the viewpoint of the balance between the properties of the resin composition containing the fibrous substance and the resin (for example, mechanical properties), the polyoxyethylene chain length May be 60 or less, or 50 or less, or 40 or less, or 30 or less, or 20 or less.

As for the structure of the hydrophobic group of the surfactant, alkyl ether type, alkyl phenyl ether type, rosin ester type, bisphenol A type, β naphthyl type, styrenated phenyl type, and cured castor oil are used because of their high affinity with the resin. The mold is preferred. The number of carbon atoms of the alkyl chain of the hydrophobic group (in the case of alkylphenyl, the number of carbon atoms excluding the phenyl group) is preferably 5 or more, 10 or more, or 12 or more, or 16 or more. For example, when the resin is a polyolefin resin, the higher the carbon number of the surfactant, the higher the affinity with the resin. The carbon number may be, for example, 30 or less, or 25 or less.

In one aspect, the dispersion contains particulate components. The particulate component can be solid or liquid. Examples of the solid include spherical silica, cellulose nanocrystals, nanoclay, and nanotalc, and examples of the liquid include dispersed phases in emulsions (for example, polyurethane, polyamide, modified polypropylene, vinyl acetate, ABS, etc.). Examples of the size of the particulate component include 0.001 to 20 μm, 0.01 to 10 μm, and 0.1 to 1 μm.

<Dispersion stabilizer>
In one embodiment, the dispersion may further contain a dispersion stabilizer. The dispersion stabilizer of the present disclosure has a function of stably dispersing a fibrous substance, and is a resin composition produced by using a dispersion liquid by improving or controlling the dispersion state of the fibrous substance in the resin. It means a compound that improves the mechanical properties of a substance. Dispersion stabilizers are distinguished from the thickeners of the present disclosure by their small contribution of fibrous material to the sedimentation degree α. In one aspect, the sedimentation degree (with sedimentation degree B) when 2 parts by mass is added to 100 parts by mass of the dispersion liquid (having a sedimentation degree A) in which the fibrous substance is dispersed at a concentration of 0.05% by mass. The thickener satisfies the relational expression: (settling degree B) <(settling degree A) × 0.9, and the relational expression: (settling degree A) × 0.9 ≦ (settling degree B) ≦ ( A dispersion stabilizer that satisfies the sedimentation degree A) × 1.1 is used. In a preferred embodiment, the fibrous material is dispersed in the resin composition in the form of a dispersion containing the dispersion stabilizer and the fibrous material dispersed in the dispersion stabilizer. That is, the resin composition is preferably one in which a dispersion in which a fibrous substance is dispersed in a dispersion stabilizer is dispersed in the resin. The mass ratio of the fibrous substance to 100% by mass of the total of the fibrous substance and the dispersion stabilizer is preferably 5% by mass or more, 10% by mass or more, or 20% by mass or more, preferably 90% by mass or less. Or 80% by mass or less, or 50% by mass or less. The dispersion stabilizer is selected from the group consisting of surfactants (excluding those included in thickeners), organic compounds having a boiling point of 160 ° C. or higher, and resins having a chemical structure capable of highly dispersing fibrous substances. It can be at least one kind, and is preferably at least one kind selected from the group consisting of a surfactant and an organic compound having a boiling point of 160 ° C. or higher.

As the surfactant as the dispersion stabilizer, any of anionic surfactants, nonionic surfactants, amphoteric ionic surfactants, and cationic surfactants can be used, but fibers. Anionic surfactants and nonionic surfactants are preferable, and nonionic surfactants are more preferable, from the viewpoint of affinity with the state substance.

As the hydrophilic group of the surfactant, a polyoxyethylene chain, a carboxyl group, and a hydroxyl group are preferable, and a polyoxyethylene chain is particularly preferable, in terms of affinity with a fibrous substance. Nonionic polyoxyethylene derivatives are particularly preferred. The polyoxyethylene chain length of the polyoxyethylene derivative may be 3 or more, 5 or more, 10 or more, or 15 or more. The longer the chain length, the higher the affinity with fibrous substances (particularly cellulose fibers), but from the viewpoint of balance with the desired properties (for example, mechanical properties) of the resin composition, the polyoxyethylene chain length is 60 or less. Or it may be 50 or less, 40 or less, 30 or less, or 20 or less.

As for the structure of the hydrophobic group of the surfactant, alkyl ether type, alkyl phenyl ether type, rosin ester type, bisphenol A type, β naphthyl type, styrenated phenyl type, and cured castor oil are used because of their high affinity with the resin. The mold is preferred. The number of carbon atoms of the alkyl chain of the hydrophobic group (in the case of alkylphenyl, the number of carbon atoms excluding the phenyl group) is preferably 5 or more, 10 or more, or 12 or more, or 16 or more. For example, when the resin is a polyolefin resin, the higher the carbon number of the surfactant, the higher the affinity with the resin. The carbon number may be, for example, 30 or less, or 25 or less.

As the hydrophobic group, one having a cyclic structure or one having a bulky polyfunctional structure is more preferable. As the hydrophobic group having a cyclic structure, an alkylphenyl ether type, a rosin ester type, a bisphenol A type, a β-naphthyl type, and a styrene phenyl type group are preferable, and as a group having a polyfunctional structure, a cured castor oil type (for example, A group of hardened castor oil ether) is preferred. The rosin ester type and the cured castor oil type are particularly preferable.

In a preferred embodiment, the surfactant is a polyethylene glycol (PEG) -polypropylene glycol (PPG) copolymer.

<Agglomerate>
In the fibrous substance dispersion liquid, the liquid composition becomes non-uniform when aggregates are formed by the entanglement of the fibrous substances. Regarding the degree of formation of aggregates, an appropriate amount of fibrous substance dispersion was collected, sandwiched between two flat plates (for example, glass plates), and crushed by sandwiching with a force of 0.05 MPa, and the number of aggregates and the number of aggregates were observed. It can be evaluated by measuring the size. For example, the number of aggregates measured by the above method by collecting 0.3 g of the dispersion is preferably 50 or less, 10 or less, or 1 or less, and the size is preferably 25 mm ² or less, or It is 10 mm ² or less, or 1 mm ² or less. The smaller the number and size values are, the more preferable.

<Liquid permeability>
When the fibrous substance dispersion liquid is passed through a narrow flow path, the liquid permeability may decrease due to the above-mentioned phase separation (that is, separation / exudation of liquid components) and / or formation of aggregates. As a method for evaluating the liquid permeability, there is a method in which a fibrous substance dispersion liquid is passed through a strainer having an appropriate opening (specifically, 400 μm) and the time until clogging occurs is measured. The liquid permeability measured by the above method is preferably 10 minutes or longer, 1 hour or longer, or 24 hours or longer. The greater the liquid permeability of the dispersion, the more preferable it is, but from the viewpoint of ease of production of the dispersion, for example, it may be 5000 hours or less, 1000 hours or less, or 100 hours or less.

<Stable supply of fibrous material dispersion>
As a method for evaluating the stable supply of the fibrous substance dispersion liquid, the supply amount and the fibrous substance concentration when the fibrous substance dispersion liquid is to be transferred using a transfer device such as a pump are measured over time and are stable. There is a method of determining whether or not the fibrous substance dispersion liquid can be supplied. In one embodiment, a tube pump having an inner diameter of 5 mm is used, and the transfer conditions are set to the same tube pump rotation speed at which distilled water is transferred at 150 g / min, and the fibrous substance dispersion liquid to the resin pipe having a pipe diameter of 10 mm is used. When the transfer is performed, the discharged material is received in a container, and the concentration and supply amount (g / min) are measured every minute, the standard deviation (n = 10) of the supply amount is within 50%, preferably 10%. Within, more preferably within 5%, and the standard deviation of concentration (n = 10) is preferably within 30%, preferably within 10%, more preferably within 5%.

One aspect of the present invention is
Provided is a method for improving the liquid transfer property of a fibrous substance dispersion liquid containing a dispersion medium and a fibrous substance dispersed in the dispersion medium. The method is
The following formula (1): of the test dispersion prepared from the fibrous substance dispersion:
α = 1-([A] / [B]) ... (1)
(In the formula (1), [A] is the height from the bottom surface of the dispersion liquid to the separation interface, and [B] is the height from the bottom surface of the dispersion liquid to the top surface of the dispersion liquid.)
This includes adding a thickener to the fibrous material dispersion so that the sedimentation degree α obtained according to the above is 80% or less. The test dispersion is the fibrous substance dispersion itself when the concentration of the fibrous substance in the fibrous substance dispersion is 0.05% by mass, and the test dispersion is the fibrous substance dispersion itself when the concentration is not 0.05% by mass. , The fibrous substance dispersion is concentrated or diluted with the same dispersion medium as the dispersion medium so that the concentration becomes 0.05% by mass. The details of the method for measuring the sedimentation degree α, the method for preparing the test dispersion, and the thickener are the same as described above.

≪Resin composition≫
One aspect of the present invention also provides a resin composition containing a fibrous substance and a resin. In one embodiment, the fibrous material has an average fiber diameter of 1 to 1000 nm. In one aspect, the resin composition comprises a thickener. In one aspect, the resin composition can be produced using the dispersions of the present disclosure.

<Resin>
As the resin, a thermoplastic resin, a thermosetting resin, and a photocurable resin can be used. The resin may be an elastomer. From the viewpoint of moldability and productivity, a thermoplastic resin is more preferable.

(Thermoplastic resin)
When the resin is a thermoplastic resin, the melting point of the thermoplastic resin may be appropriately selected depending on the use of the resin composition and the like. As the melting point of the thermoplastic resin, for example, for a resin having a relatively low melting point (for example, a polyolefin resin), 150 ° C. to 190 ° C., or 160 ° C. to 180 ° C., for example, a resin having a relatively high melting point (for example, a polyamide resin). Can be exemplified with respect to 220 ° C. to 350 ° C. or 230 ° C. to 320 ° C.

The thermoplastic resin is preferably at least one selected from the group consisting of polyolefin resins, polyacetate resins, polycarbonate resins, polyamide resins, polyester resins, polyphenylene ether resins, and acrylic resins. Can be done.

A preferred polyolefin resin as a thermoplastic resin is a polymer obtained by polymerizing olefins (for example, α-olefins) and / or alkenes as a monomer unit. Specific examples of the polyolefin-based resin include ethylene-based (co) polymers such as low-density polyethylene (for example, linear low-density polyethylene), high-density polyethylene, ultra-low-density polyethylene, and ultra-high-molecular-weight polyethylene, polypropylene, and ethylene. Polypropylene-based (co) copolymers such as -propylene copolymer, ethylene-propylene-diene copolymer, etc., ethylene-acrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-glycidyl methacrylate copolymer Examples thereof include a copolymer of ethylene and α-olefin typified by coalescence.

Here, polypropylene is mentioned as the most preferable polyolefin resin. In particular, polypropylene having a melt mass flow rate (MFR) of 3 g / 10 minutes or more and 30 g / 10 minutes or less measured at 230 ° C. and a load of 21.2 N in accordance with ISO1133 is preferable. The lower limit of MFR is more preferably 5 g / 10 min, even more preferably 6 g / 10 min, and most preferably 8 g / 10 min. The upper limit is more preferably 25 g / 10 minutes, even more preferably 20 g / 10 minutes, and most preferably 18 g / 10 minutes. It is desirable that the MFR does not exceed the above upper limit value from the viewpoint of improving the toughness of the resin composition, and it is desirable that the MFR does not exceed the above lower limit value from the viewpoint of the fluidity of the resin composition.

Further, in order to enhance the affinity with fibrous substances (particularly cellulose fibers), an acid-modified polyolefin resin can also be preferably used. As the acid used for acid modification, mono or polycarboxylic acid can be used, and examples thereof include maleic acid, fumaric acid, succinic acid, phthalic acid and their anhydrides, citric acid and the like. Maleic acid or its anhydride is particularly preferable because of the ease of increasing the denaturation rate. The modification method is not particularly limited, but a general method is to heat the polyolefin resin to a temperature higher than the melting point and melt-knead it in the presence or absence of a peroxide. As the acid-modified polyolefin resin, all of the above-mentioned polyolefin resins can be used, but polypropylene is particularly preferable. The acid-modified polypropylene-based resin may be used alone, but it is more preferable to use the acid-modified polypropylene-based resin in combination with an unmodified polypropylene-based resin in order to adjust the modification rate of the resin as a whole. At this time, the ratio of the acid-modified polypropylene-based resin to all the polypropylene-based resins is preferably 0.5% by mass to 50% by mass. A more preferable lower limit is 1% by mass, 2% by mass, or 3% by mass, or 4% by mass, or 5% by mass. Further, a more preferable upper limit is 45% by mass, 40% by mass, or 35% by mass, or 30% by mass, or 20% by mass. In order to maintain the interfacial strength between the resin and the fibrous substance (particularly cellulose fiber), the lower limit or more is preferable, and in order to maintain the ductility of the resin, the upper limit or less is preferable.

The melt mass flow rate (MFR) of an acid-modified polypropylene resin measured at 230 ° C. and a load of 21.2 N in accordance with ISO 1133 determines the affinity at the interface between the resin and fibrous substances (particularly cellulosic fibers). From the viewpoint of enhancing, it is preferably 50 g / 10 minutes or more, 100 g / 10 minutes or more, 150 g / 10 minutes or more, or 200 g / 10 minutes or more. The upper limit is not particularly limited, but is preferably 500 g / 10 minutes from the viewpoint of maintaining mechanical strength.

Preferred polyamide-based resins for the thermoplastic resin are: polyamides obtained by polycondensation of lactams (eg polyamide 6, polyamide 11, polyamide 12, etc.); diamines (eg 1,6-hexanediamine, 2-methyl-1). , 5-Pentanediamine, 1,7-Heptanediamine, 2-Methyl-1-6-hexanediamide, 1,8-Octanediamine, 2-Methyl-1,7-Heptanediamine, 1,9-Nonandiamine, 2- Methyl-1,8-octanediamide, 1,10-decanediamide, 1,11-undecanediamine, 1,12-dodecanediamide, m-xylylene diamine, etc.) and dicarboxylic acids (eg butane diic acid, pentan diic acid, etc.) Hexanic acid, heptanedioic acid, octane diic acid, nonane diic acid, decanedioic acid, benzene-1,2-dicarboxylic acid, benzene-1,3-dicarboxylic acid, benzene-1,4 dicarboxylic acid, cyclohexane-1, Polyamide (for example, polyamide 6, 6, polyamide 6, 10, polyamide 6, 11, polyamide 6, 12, polyamide 6, T) obtained as a copolymer with 3-dicarboxylic acid, cyclohexane-1,4-dicarboxylic acid, etc. , Polyamide 6, I, Polyamide 9, T, Polyamide 10, T, Polyamide 2M5, T, Polyamide MXD, 6, Polyamide 6, C, Polyamide 2M5, C, etc.); For example, polyamide 6, T / 6, I, etc.).

Among these polyamide-based resins, aliphatic polyamides such as polyamide 6, polyamide 11, polyamide 12, polyamide 6, 6, polyamide 6, 10, polyamide 6, 11, polyamide 6, 12 and polyamide 6, C, polyamide 2M5 , C and other alicyclic polyamides are more preferable.

From the viewpoint of improving the heat resistance of the resin composition, the melting point of the polyamide resin is preferably 220 ° C. or higher, 230 ° C. or higher, or 240 ° C. or higher, or 245 ° C. or higher, or 250 ° C. or higher, and the resin composition. From the viewpoint of ease of manufacturing the product, the melting point is preferably 350 ° C. or lower, 320 ° C. or lower, or 300 ° C. or lower.

The concentration of the terminal carboxyl group of the polyamide resin is not particularly limited, but is preferably 20 μmol / g or more, or 30 μmol / g or more, and preferably 150 μmol / g or less, or 100 μmol / g or less, or It is 80 μmol / g or less.

In a polyamide resin, the ratio of carboxyl terminal groups to total terminal groups ([COOH] / [total terminal groups]) is preferably from the viewpoint of dispersibility of fibrous substances (particularly cellulose fibers) in the resin composition. It is 0.30 or more, 0.35 or more, 0.40 or more, or 0.45 or more, and is preferably 0.95 or less, or 0.90 or less, or 0 from the viewpoint of the color tone of the resin composition. It is .85 or less, or 0.80 or less.

The terminal group concentration of the polyamide resin can be adjusted by a known method. As a preparation method, a terminal modifier (for example, a diamine compound, a monoamine compound, a dicarboxylic acid compound, a monocarboxylic acid compound, an acid anhydride, or a mono) that reacts with a terminal group so as to have a predetermined terminal group concentration during polymerization of polyamide is used. Examples thereof include a method of adding (isocyanate, monoacid halide, monoester, monoalcohol, etc.) to the polymerization solution.

Examples of the terminal modifier that reacts with the terminal amino group include acetic acid, propionic acid, butylic acid, valeric acid, caproic acid, capric acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, and isobutylic acid. Alicyclic monocarboxylic acid such as aliphatic monocarboxylic acid; alicyclic monocarboxylic acid such as cyclohexanecarboxylic acid; aromatic monocarboxylic acid such as benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid and phenylacetic acid ; And a plurality of mixtures arbitrarily selected from these. Among these, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, etc. One or more terminal modifiers selected from the group consisting of benzoic acid and benzoic acid are preferable, and acetic acid is most preferable.

Aliphatic monoamines such as methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine and dibutylamine; Aliphatic monoamines such as cyclohexylamines and dicyclohexylamines; aromatic monoamines such as aniline, toluidine, diphenylamines and naphthylamines and any mixtures thereof. Among these, one or more terminals selected from the group consisting of butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine and aniline from the viewpoints of reactivity, boiling point, stability of sealing terminal, price and the like. Regulators are preferred.

The concentrations of the amino-terminal group and the carboxyl-terminal group of the polyamide resin ^{can be determined by 1} H-NMR from the integrated value of the characteristic signal corresponding to each terminal group. This method is preferable in terms of accuracy and simplicity. More specifically, it is recommended to use the method described in JP-A-7-228775, to use heavy trifluoroacetic acid as the measurement solvent, and to set the number of integrations to 300 scans or more.

The intrinsic viscosity [η] of the polyamide resin measured under the condition of 30 ° C. in concentrated sulfuric acid has good fluidity in the mold and a good appearance of the molded piece when the resin composition is injection-molded, for example. From the viewpoint, preferably 0.6 to 2.0 dL / g, or 0.7 to 1.4 dL / g, or 0.7 to 1.2 dL / g, or 0.7 to 1.0 dL / g. is there. In the present disclosure, "intrinsic viscosity" is synonymous with viscosity generally called intrinsic viscosity. For the intrinsic viscosity, ηsp / c of several measuring solvents having different concentrations was measured under a temperature condition of 30 ° C. in 96% concentrated sulfuric acid, and the relational expression between each ηsp / c and the concentration (c) was calculated. It is obtained by deriving and extrapolating the concentration to zero. The value extrapolated to zero is the intrinsic viscosity. Details of the above method are described, for example, on pages 291 to 294 of Prentice-Hall, Inc. (Prentice-Hall, Inc. 1994). It is accurate that the concentration in some measurement solvents having different concentrations is at least 4 points (for example, 0.05 g / dL, 0.1 g / dL, 0.2 g / dL, 0.4 g / dL). Desirable from the point of view.

Preferred polyester resins as the thermoplastic resin include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), and polybutylene. One or more selected from adipate terephthalate (PBAT), polyhydroxyalkanoic acid (PHA), polylactic acid (PLA), polyallylate (PAR) and the like can be used. Among them, PET, PBS, PBSA, PBT and PEN are more preferable, and PBS, PBSA and PBT are particularly preferable.

The terminal group of the polyester resin can be arbitrarily changed depending on the monomer ratio at the time of polymerization, the presence / absence and amount of the terminal stabilizer added, and the like. The ratio of carboxyl end groups to all end groups ([COOH] / [all end groups]) of the polyester resin is preferably 0. From the viewpoint of dispersibility of fibrous substances (particularly cellulose fibers) in the resin composition. It is 30 or more, 0.35 or more, or 0.40, or 0.45, and is preferably 0.95 or less, or 0.90 or less, or 0.85 from the viewpoint of the color tone of the resin composition. Below, or 0.80 or less.

As the preferred polyacetal resin as the thermoplastic resin, homopolyacetal using formaldehyde as a raw material and copolyacetal containing trioxane as a main monomer and 1,3-dioxolan as a comonomer component are generally used, and both can be used. However, copolyacetal is preferable from the viewpoint of thermal stability during processing. The amount of the structure derived from the comonomer component (for example, 1,3-dioxolane) is preferably 0.01 mol% or more, 0.05 mol% or more, or 0 from the viewpoint of thermal stability during extrusion processing and molding processing. .1 mol% or more, or 0.2 mol% or more, preferably 4 mol% or less, 3.5 mol% or less, or 3.0 mol% or less, or 2. It is 5 mol% or less, or 2.3 mol% or less.

(Thermosetting resin)
Examples of the thermosetting resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol E type epoxy resin, bisphenol M type epoxy resin, bisphenol P type epoxy resin, and bisphenol Z type epoxy resin. Novolak type epoxy resin such as bisphenol type epoxy resin, bisphenol A novolac type epoxy resin, phenol novolac type epoxy resin, cresol novolac epoxy resin, biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, arylalkylene type epoxy resin, tetraphenylol ethane Type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, phenoxy type epoxy resin, dicyclopentadiene type epoxy resin, norbornene type epoxy resin, adamantan type epoxy resin, fluorene type epoxy resin, glycidyl methacrylate copolymer type epoxy resin, Copolymerized epoxy resin of cyclohexyl maleimide and glycidyl methacrylate, epoxy-modified polybutadiene rubber derivative, CTBN-modified epoxy resin, trimethylolpropane polyglycidyl ether, phenyl-1,3-diglycidyl ether, biphenyl-4,4'-di Glycidyl ether, 1,6-hexanediol diglycidyl ether, ethylene glycol or propylene glycol diglycidyl ether, sorbitol polyglycidyl ether, tris (2,3-epoxypropyl) isocyanurate, triglycidyltris (2-hydroxyethyl) isocia Novolak type phenol resin such as nurate, phenol novolac resin, cresol novolak resin, bisphenol A novolak resin, unmodified resolephenol resin, oil-modified resolephenol resin modified with tung oil, flaxseed oil, walnut oil, etc. Such as phenol resin, phenoxy resin, urea (ureia) resin, triazine ring-containing resin such as melamine resin, unsaturated polyester resin, bismaleimide resin, diallyl phthalate resin, silicone resin, resin having benzoxazine ring, norbornene resin, etc. Examples thereof include cyanate resin, isocyanate resin, urethane resin, benzocyclobutene resin, maleimide resin, bismaleimide triazine resin, polyazomethin resin, and thermosetting polyimide.

(Photocurable resin)
Examples of the photocurable resin include (meth) acrylate resin, vinyl resin, epoxy resin and the like. These are roughly classified into a radical reaction type in which a monomer reacts with a radical generated by light and a cationic reaction type in which a monomer is cationically polymerized, depending on the reaction mechanism. Examples of the radical reaction type monomer include (meth) acrylate compounds and vinyl compounds (for example, some vinyl ethers). Epoxy compounds, certain vinyl ethers, and the like correspond to the cationic reaction type. For example, the epoxy compound that can be used as a cationic reaction type can be a monomer of both a thermosetting resin and a photocurable resin.

The (meth) acrylate compound is a compound having one or more (meth) acrylate groups in the molecule. Examples of the (meth) acrylate compound include monofunctional (meth) acrylate, polyfunctional (meth) acrylate, epoxy acrylate, polyester acrylate, urethane acrylate and the like.

Examples of the vinyl compound include vinyl ether, styrene and styrene derivatives. Examples of the vinyl ether include ethyl vinyl ether, propyl vinyl ether, hydroxyethyl vinyl ether, ethylene glycol divinyl ether and the like. Examples of the styrene derivative include methylstyrene and ethylstyrene. Examples of other vinyl compounds include triallyl isocyanurate and trimetaallyl isocyanurate.

A so-called reactive oligomer may be used as a raw material for the photocurable resin. As the reactive oligomer, an oligomer having an arbitrary combination selected from a (meth) acrylate group, an epoxy group, a urethane bond, and an ester bond in the same molecule, for example, a (meth) acrylate group and a urethane bond in the same molecule. Urethane acrylate having both (meth) acrylate group and ester bond in the same molecule, epoxy acrylate derived from epoxy resin and having epoxy group and (meth) acrylate group in the same molecule, etc. Be done.

(Elastomer)
Examples of the elastomer (that is, rubber) include natural rubber (NR), butadiene rubber (BR), styrene-butadiene copolymer rubber (SBR), isoprene rubber (IR), butyl rubber (IIR), acrylonitrile-butadiene rubber (NBR), and the like. Acrylonitrile-styrene-butadiene copolymer rubber, chloroprene rubber, styrene-isoprene copolymer rubber, styrene-isoprene-butadiene copolymer rubber, isoprene-butadiene copolymer rubber, chlorosulfonated polyethylene rubber, modified natural rubber ( Epoxidized natural rubber (ENR), hydrogenated natural rubber, deproteinized natural rubber, etc.), ethylene-propylene copolymer rubber, acrylic rubber, epichlorohydrin rubber, polysulfide rubber, silicone rubber, fluororubber, urethane rubber, etc. ..

The amount of the fibrous substance with respect to 100 parts by mass of the resin (thermoplastic resin in one embodiment) is preferably in the range of 0.001 to 100 parts by mass. The lower limit of the amount of the fibrous substance is more preferably 0.01 part by mass, further preferably 0.1 part by mass, and most preferably 1 part by mass. The upper limit of the amount of the fibrous substance is more preferably 80 parts by mass, further preferably 70 parts by mass, and most preferably 50 parts by mass. From the viewpoint of the balance between workability and mechanical properties, it is desirable that the amount of fibrous substance is within the above range.

In one embodiment, the amount of the thickener with respect to 100 parts by mass of the resin (in one embodiment, the thermoplastic resin) is preferably 0.00001 parts by mass or more, 0.0001 parts by mass or more, or 0.001 parts by mass or more. Alternatively, it may be 0.01 parts by mass or more, preferably 5 parts by mass or less, 3% by mass or less, 1% by mass or less, or 0.5% by mass or less.

The ratio (TEb / TEy) of the tensile yield elongation TEy and the tensile elongation at break TEb of the resin composition of the present disclosure is preferably large from the viewpoint of improving the elongation by improving the dispersibility of the fibrous material. It is preferably 0 or more, 1.5 or more, or 2.0 or more. When the above ratio is large, the resin composition yields before breaking and exhibits good elongation. The larger the ratio is, the more preferable it is from the viewpoint of improving the elongation, but from the viewpoint of ease of production, in one aspect, it may be 1000 or less, 100 or less, or 10 or less.

When the resin composition of the present disclosure contains a thickener, the ratio of the tensile strength of the resin composition to the tensile strength of the comparative resin composition having the same composition except that it does not contain the thickener is the ratio of the fibrous substance. From the viewpoint of improving the strength by improving the dispersibility, the larger one is preferable, and 1.01 times or more, 1.05 times or more, 1.10 times or more, or 1.15 times or more is preferable. The larger the ratio is, the more preferable it is from the viewpoint of improving the elongation, but from the viewpoint of ease of production, in one aspect, it may be 100 times or less, 10 times or less, or 5 times or less.

≪Manufacturing method of resin composition≫
When the resin is a thermoplastic resin, the fibrous substance dispersion liquid of the present disclosure or a dried product obtained by drying the dispersion liquid (hereinafter, also simply referred to as a dried product) is kneaded with a thermoplastic resin to form a resin composition. Can manufacture things. As a more specific manufacturing method of the resin composition,
-A method of mixing a resin monomer with a fibrous substance dispersion or a dried product, carrying out a polymerization reaction, extruding the obtained resin composition into a strand shape, cooling and solidifying in a water bath, and obtaining a pellet-shaped molded product.
-A method of melt-kneading a mixture of a resin and a fibrous substance dispersion or a dried product using a single-screw or twin-screw extruder, extruding it into a strand, and cooling and solidifying it in a water bath to obtain a pellet-shaped molded product.
-A method in which a mixture of a resin and a fibrous substance dispersion or a dried product is melt-kneaded using a single-screw or twin-screw extruder, extruded into a rod or cylinder, and cooled to obtain an extruded product.
-A method of melt-kneading a mixture of a resin and a fibrous substance dispersion or a dried product using a single-screw or twin-screw extruder to obtain an extruded sheet or a film-shaped molded product from a T-die.
And so on. In a preferred embodiment, a single-screw or twin-screw extruder is used to melt-knead a mixture of resin and fibrous material dispersion or dried product, extrude into strands, cool and solidify in a water bath, and pellet-molded product. To get.
Specific examples of the method for melt-kneading the resin and the fibrous material dispersion or the dried product include a method in which the resin and the fibrous material dispersion or the dried product transported in a desired ratio are mixed and then melt-kneaded. Be done.
When the resin is a thermoplastic resin, the minimum processing temperature recommended by the thermoplastic resin supplier is 255 to 270 ° C for nylon 66, 225 to 240 ° C for nylon 6, 170 ° C to 190 ° C for polyacetal resin, and 160 ° C for polypropylene. ~ 180 ° C. The heating set temperature is preferably in the temperature range of 20 ° C. higher than these recommended minimum processing temperatures. By setting the mixing temperature within this temperature range, the fibrous substance and the resin can be uniformly mixed.

Resin compositions containing a thermoplastic resin as a resin can be provided in various shapes. Specific examples thereof include a resin pellet shape, a sheet shape, a fibrous shape, a plate shape, a rod shape, and the like, but the resin pellet shape is more preferable from the viewpoint of ease of post-processing and ease of transportation. Preferred pellet shapes at this time include a round shape, an elliptical shape, a cylindrical shape, and the like, which differ depending on the cutting method at the time of extrusion processing. Pellets cut by a cutting method called underwater cut often have a round shape, and pellets cut by a cutting method called hot cut often have a round or oval shape, which is called a strand cut. Pellets cut by the method often have a columnar shape. In the case of round pellets, the preferred size is 1 mm or more and 3 mm or less as the pellet diameter. Further, in the case of columnar pellets, the preferable diameter is 1 mm or more and 3 mm or less, and the preferable length is 2 mm or more and 10 mm or less. The above diameter and length are preferably not more than the lower limit from the viewpoint of operational stability during extrusion, and preferably not more than the upper limit from the viewpoint of biting into the molding machine in post-processing.

Resin compositions containing a thermoplastic resin as a resin can be used as various resin molded products. The method for producing the resin molded product is not particularly limited, and any production method may be used, but an injection molding method, an extrusion molding method, a blow molding method, an inflation molding method, a foam molding method, or the like can be used. Of these, the injection molding method is the most preferable from the viewpoint of design and cost.

When the resin is a thermosetting resin or a photocurable resin, for example, a method of sufficiently dispersing a fibrous substance dispersion liquid or a dried product in a resin solution or a resin powder dispersion and drying the resin, fibers in a resin monomer liquid. A method of sufficiently dispersing a state material dispersion or a dried body and polymerizing with heat, UV irradiation, a polymerization initiator, etc., a molded body composed of a dried body of a fibrous substance dispersion (for example, a sheet, a powder particle molded body, etc.) Is sufficiently impregnated with a resin solution or a resin powder dispersion and dried, or a molded product made of a dried fibrous substance dispersion is sufficiently impregnated with a resin monomer solution and subjected to heat, UV irradiation, a polymerization initiator, etc. The resin composition can be produced by a method of polymerization or the like. At the time of curing, various polymerization initiators, curing agents, curing accelerators, polymerization inhibitors and the like can be blended.

When the resin is a thermosetting resin or a photocurable resin, a sheet called an uncured or semi-cured prepreg is prepared, and then the prepreg is made into a single layer or a laminated layer, and the resin is cured and molded by pressurization and heating. The method may be used. Examples of the pressurizing and heating methods include a press molding method, an autoclave molding method, a bagging molding method, a lapping tape method, and an internal pressure molding method.

When the resin is a photocurable resin, a resin molded product can be produced by using various curing methods using active energy rays.

When the resin is an elastomer, a method of kneading the dried body of the fibrous substance dispersion liquid and the raw material rubber in a dry manner, or dispersing or dissolving the dispersion or the dried body of the fibrous substance dispersion liquid and the raw material rubber in a dispersion medium. After that, the resin composition can be produced by a method of drying and mixing. As the mixing method, a homogenizer mixing method is preferable in that high shearing force and pressure can be applied to promote dispersion, but in addition, a propeller type stirring device, a rotary stirring device, an electromagnetic stirring device, manual stirring, etc. The method can also be used. A resin composition containing an elastomer is molded by a desired molding method such as mold molding, injection molding, extrusion molding, hollow molding, foam molding, etc., and unsulfurized in a desired shape such as a sheet, pellet, powder, etc. A molded product can be obtained. The unvulcanized molded product can be vulcanized by heat treatment or the like, if necessary, to obtain a resin molded product.

A resin molded product containing a thermoplastic resin or an elastomer may be used by heat-treating a part (for example, several places) thereof to melt it and adhering it to a resin or metal substrate, for example. Further, the resin molded body may be a coating film applied to a resin or metal substrate, or may form a laminate with the substrate. Further, the sheet-shaped, film-shaped or fibrous resin molded body may be subjected to secondary processing such as annealing treatment, etching treatment, corona treatment, plasma treatment, grain transfer, cutting and surface polishing.

Since the resin composition of the present disclosure has improved transportability of fibrous substances, stable production is possible, there is little variation, and stable physical properties can be exhibited.

The present invention will be further described with reference to the examples, but the present invention is not limited to these examples.

[Ingredients and evaluation method]
The raw materials used and the evaluation method will be described below.

≪Thermoplastic resin (polyamide resin) ≫
-"UBE Nylon 1013B" Polyamide 6 manufactured by Ube Industries, Ltd. (hereinafter referred to as PA)
Carboxylic acid end group ratio is ([COOH] / [all end groups]) = 0.59

≪Thermoplastic resin (polypropylene resin) ≫
・ Made of Prime Polypro J105G Prime Polymer

≪Fibrous substance (cellulose fiber) ≫
-Cellulose fiber A (hereinafter, may be abbreviated as CNF-A)
After cutting the filter paper, 1 part by mass was stirred at 500 rpm for 1 hour at room temperature in 30 parts by mass of dimethyl sulfoxide (DMSO) using a uniaxial stirrer (DKV-1 φ125 mm dissolver manufactured by IMEX). Subsequently, it was fed to a bead mill (NVM-1.5 manufactured by Imex) with a hose pump and circulated for 180 minutes using only DMSO to prepare a fine cellulose fiber slurry (S1, DMSO solvent) having a solid content of 3.2% by mass. 31 parts by mass was obtained.
During the circulation operation, the rotation speed of the bead mill was 2500 rpm and the peripheral speed was 12 m / s, and the beads used were made of zirconia, φ2.0 mm, and the filling rate was 70% (the slit gap of the bead mill was 0.6 mm). Further, during the circulation operation, the slurry temperature was controlled to 40 ° C. by a chiller in order to absorb heat generated by friction.
After adding 30 parts by mass of pure water to the slurry S1 and stirring it sufficiently, it was put into a dehydrator and concentrated. DMSO is removed by repeating the washing operation of dispersing, stirring, and concentrating the obtained wet cake in 30 parts by mass of pure water again a total of 5 times, and a fine cellulose fiber cake (K1, water) having a solid content of 10% by mass is removed. Solvent) was obtained in an amount of 10 parts by mass.

(Acetylation process)
The obtained cellulose fiber precursor A was acetylated to obtain cellulose fiber A.
After the slurry S2 in Example 2 was put into an explosion-proof disperser tank, 3.2 parts by mass of vinyl acetate and 0.49 parts by mass of sodium hydrogen carbonate were added, the temperature in the tank was set to 50 ° C., and stirring was performed for 120 minutes. 35 parts by mass of a slurry (DMSO solvent) having a solid content of 2.9% by mass was obtained. In order to stop the reaction, 30 parts by mass of pure water was added, the mixture was sufficiently stirred, and then the mixture was placed in a dehydrator for concentration. By repeating the washing operation of dispersing, stirring, and concentrating the obtained wet cake in 30 parts by mass of pure water again a total of 5 times, unreacted reagents and solvents were removed, and acetylation with a solid content of 10% by mass was performed. 10 parts by mass of a fine cellulose fiber cake (K3, aqueous solvent) was obtained.
Average fiber diameter = 90 nm
Crystallinity = 80%
Degeneration (DS) = 1.02
Mw = 360000, Mw / Mn = 2
Average content of alkali-soluble polysaccharides = 8.3% by mass

-Cellulose fiber B (hereinafter, may be abbreviated as CNF-B)
A slurry of CNF-B was obtained in the same procedure as in the production of CNF-A except that the temperature in the tank was 40 ° C. and the stirring time was 60 minutes. The characteristics of the obtained CNF were evaluated by the method described later. The results are shown below.
Average fiber diameter = 90 nm
Crystallinity = 82%
Degeneration (DS) = 0.50
Mw = 410000, Mw / Mn = 3.2
Average content of alkali-soluble polysaccharides = 7.1% by mass

-Cellulose fiber C (hereinafter, may be abbreviated as CNF-C)
A slurry of CNF-B was obtained in the same procedure as in the production of CNF-A except that the temperature in the tank was 30 ° C. and the stirring time was 30 minutes. The characteristics of the obtained CNF were evaluated by the method described later. The results are shown below.
Average fiber diameter = 92 nm
Crystallinity = 84%
Degeneration (DS) = 0.30
Mw = 380000, Mw / Mn = 2.5
Average content of alkali-soluble polysaccharides = 7.5% by mass

≪Evaluation of cellulose fiber≫
The physical characteristics of the cellulose fibers were evaluated using a porous sheet prepared by the following method.
[Porous sheet]
First, the wet cake was added to tert-butanol, and further dispersed with a mixer or the like until there were no agglutinates. The concentration was adjusted to 0.5% by mass with respect to the weight of the cellulose fiber solid content of 0.5 g. 100 g of the obtained tert-butanol dispersion was filtered on a filter paper, dried at 150 ° C., and then the filter paper was peeled off to obtain a sheet. A porous sheet having an air permeation resistance of 100 sec / 100 ml or less per ^{10 g / m 2 of the sheet was used as a measurement sample.
After measuring the basis weight W (g / m 2} ) of the sample left to stand in an environment of 23 ° C. and 50% RH for 1 day, a Wangken type air permeability resistance tester (manufactured by Asahi Seiko Co., Ltd., model EG01) was used. The air permeation resistance R (sec / 100 ml) was measured. ^{At this time, the value per 10 g / m 2} basis weight was calculated according to the following formula.
Air permeation resistance per 10 g / m ² basis weight (sec / 100 ml) = R / W x 10

[DS]
The infrared spectroscopic spectra of the porous sheet at five locations by the ATR-IR method were measured with a Fourier transform infrared spectrophotometer (FT / IR-6200 manufactured by JASCO). Infrared spectroscopic spectrum measurement was performed under the following conditions.
Accumulation number: 64 times,
Wavenumber resolution: 4 cm ^-1 ,
Wavenumber range: 4000-600cm ^-1 ,
ATR crystal: diamond,
Incident angle: 45 °
From the obtained IR spectrum, the IR index was calculated by the following formula (1):
IR index = H1730 / H1030 ... (1)
Calculated according to. In the formula, H1730 and H1030 are the absorbances at 1730 cm ^-1 and 1030 cm ^-1 (absorption band of cellulose skeleton chain CO stretching vibration). However, each of the line connecting the lines and 800 cm ^-1 and 1500 cm ^-1 connecting 1900 cm ^-1 and 1500 cm ^-1 as a baseline, means absorbance when the baseline was zero absorbance.
Then, the average degree of substitution at each measurement location was calculated from the IR index according to the following equation (2), and the average value was taken as DS.
DS = 4.13 x IR index ... (2)

[Crystallinity]
X-ray diffraction measurement of the porous sheet was performed, and the crystallinity was calculated from the following formula.
Crystallinity (%) = [I ₍₂₀₀₎ -I _(amorphous) ] / I ₍₂₀₀₎ x 100
I _{(200) : Diffraction peak intensity due to amorphous in the} cellulose type I crystal by 200 planes (2θ = 22.5 °) I (amorphous): Hello peak intensity due to amorphous in the cellulose type I crystal, 4 from the diffraction angle of 200 planes Peak intensity on the low angle side (2θ = 18.0 °) of .5 °

(X-ray diffraction measurement conditions)
Equipment MiniFlex (manufactured by Rigaku Co., Ltd.)
Operating axis 2θ / θ
Radioactive source CuKα
Measurement method Continuous voltage 40kV
Current 15mA
Start angle 2θ = 5 °
End angle 2θ = 30 °
Sampling width 0.020 °
Scan speed 2.0 ° / min
Sample: Paste a porous sheet on the sample holder

[Average fiber diameter]
The wet cake was diluted with tert-butanol to 0.01% by mass, and dispersed using a high-shear homogenizer (manufactured by IKA, trade name "Ultratalax T18") under treatment conditions: rotation speed of 25,000 rpm x 5 minutes. Casting on mica and air-dried was measured with a high-resolution scanning microscope. The measurement was performed by adjusting the magnification so that at least 100 cellulose fibers were observed, the major axis (L) of 100 randomly selected cellulose fibers was measured, and the added average of 100 cellulose fibers was calculated. Calculated.

[Weight average molecular weight (Mw), number average molecular weight (Mn) and Mw / Mn ratio]
0.88 g of the porous sheet was weighed, chopped into small pieces with scissors, stirred lightly, 20 mL of pure water was added, and the mixture was left to stand for 1 day. The water and solids were then separated by centrifugation. Subsequently, 20 mL of acetone was added, and the mixture was lightly stirred and left to stand for 1 day. Acetone and solids were then separated by centrifugation. Subsequently, 20 mL of N, N-dimethylacetamide was added, and the mixture was lightly stirred and left to stand for 1 day. After separating N, N-dimethylacetamide and solid content by centrifugation again, 20 mL of N, N-dimethylacetamide was added, and the mixture was lightly stirred and left to stand for 1 day. The N, N-dimethylacetamide and the solid content were separated by centrifugation, 19.2 g of the N, N-dimethylacetamide solution prepared so that lithium chloride was 8% by mass was added to the solid content, and the mixture was stirred with a stirrer. It was confirmed that it was visually dissolved. The solution in which cellulose was dissolved was filtered through a 0.45 μm filter, and the filtrate was used as a sample for gel permeation chromatography. The equipment and measurement conditions used are as follows.
Equipment: Tosoh HLC-8120
Column: TSKgel SuperAWM-H (6.0 mm ID x 15 cm) x 2 Detector: RI detector Eluent: N, N-dimethylacetamide (lithium chloride 0.2%)
Flow velocity: 0.6 mL / min Calibration curve: Pullulan conversion

[Average content of alkali-soluble polysaccharides]
The alkali-soluble polysaccharide content is determined from the holocellulose content (Wise method) based on the method described in the non-patent literature (Wood Science Experiment Manual, edited by Japan Wood Society, pp. 92-97, 2000) for cellulose fibers. It was calculated by subtracting the content rate. The alkali-soluble polysaccharide content was calculated three times for each sample, and the number average of the calculated alkali-soluble polysaccharide content was taken as the average alkali-soluble polysaccharide content of the cellulose fiber.

≪Fibrous substance (aramid fiber PA-Fiber) ≫
As a commercially available aramid fiber, Tiara KY400S manufactured by Daicel FineChem was used.
≪Wood flour≫
Sugi wood was crushed to about 2 to 5 mm with a cutter mill to obtain wood powder.

≪Thickener≫
As a commercially available thickener
Akovloc N-104 made of polyacrylamide MT aquapolymer
Carboxymethyl Cellulose Sodium Tokyo Chemical Industry Hydroxypropyl Cellulose Tokyo Chemical Industry Hydroxyethyl Cellulose Tokyo Chemical Industry Polyacrylic Acid Fujifilm Wako Pure Chemical Industries Polyvinyl Alcohol Tokyo Chemical Industry N-Vinyl Acetamide Tokyo Chemical Industry Polyethylene Oxide Al Cox E-300
Propylene Glycol Soluble starch made by Tokyo Chemical Industry Guar gum made by Nacalai Tesque Guar gum made by Tokyo Chemical Industry Gellan gum made by Nacalai Tesque Gelatin made by Nacalai Tesque Sodium alginate made by Nacalai Tesque was used.

≪Particular component≫
Spherical silica Snowtex (hydrophilic, 50 nm) manufactured by Nissan Chemical Industries, Ltd. was used as a commercially available particulate component.

≪Surfactant≫
As a commercially available surfactant, PEG-PPG GL-3000 manufactured by Sanyo Chemical Industries, Ltd. and hardened castor oil ether RCW-20 manufactured by Aoki Oil & Fat Co., Ltd. were used.

≪Preparation and evaluation of fibrous material dispersion ≫
The obtained fibrous substance, distilled water, and the above-mentioned commercially available thickener, particulate component, and surfactant are mixed at the ratios shown in Tables 1 and 2, and then stirred for 1 hour with a stirring blade rotating at 300 rpm. , A fibrous substance dispersion was prepared.

[Settlement α]
Distilled water was added to the obtained fibrous substance dispersion liquid so that the fibrous substance content was 0.05% by mass to prepare a test dispersion liquid. After dividing 20 ml of the test dispersion into a glass vial having a capacity of 30 ml, disperse it with a homogenizer (rotation speed 10000 rpm, 1 minute), and then quickly put 8 ml of the test dispersion into a 15 ml capacity screw cap test tube (inner diameter 12 mm). It was added, sealed, and manually shaken to homogenize the dispersion. The transmittance of the dispersion liquid at a wavelength of 850 nm (hereinafter, also referred to as initial transmittance) at this time was measured using a liquid dispersion stability evaluation device Turbiscan (manufactured by FORMULICION). Further, after allowing this test tube to stand at 23 ° C. for 24 hours, the height from the bottom surface of the dispersion liquid to the separation interface and the height from the bottom surface of the dispersion liquid to the top surface of the dispersion liquid are determined by the above-mentioned in-liquid dispersion stability evaluation device. The height at which the transmittance is 50% at the above wavelength is defined as the separation interface and measured.
α = 1-([A] / [B]) ... (1)
(In the formula (1), [A] is the height from the bottom surface of the dispersion liquid to the separation interface, and [B] is the height from the bottom surface of the dispersion liquid to the top surface of the dispersion liquid.)
Therefore, the degree of sedimentation α was determined. When the height at which the transmittance is 50% is not defined, the region having a higher transmittance than the initial transmittance is defined as the supernatant portion and the region having a lower transmittance is defined as the deposition portion, and the supernatant portion and the volume portion are used. The boundary was defined as the separation interface, and the sedimentation degree α was determined according to (1) above. The smaller the sedimentation degree α, the better the stability as a fibrous material dispersion liquid, the better the supply stability in the pump described later, and the better the handleability in transferring the dispersion liquid, so that it is industrially useful. is there. Further, the smaller the sedimentation degree α, the better the dispersibility of the fibrous substance, and therefore the better the mechanical properties (particularly the tensile elongation and the tensile strength) of the resin composition.

[Dispersiveness]
After sufficiently stirring the fibrous substance dispersion, one drop (about 0.3 mL) is dropped on a slide glass, and the two slide glasses are sandwiched with a force of 0.05 MPa to squeeze in the pipe. Was reproduced. Dispersibility was evaluated by the number of aggregates having a diameter (that is, the maximum transfer length) of 1 mm or more observed by this method.
A ... 0 pieces B ... 1 piece C ... 2-10 pieces D ... 11 pieces or more

[Supply and concentration stability]
Using a tube pump with an inner diameter of 5 mm, the transfer condition is set to the number of revolutions at which distilled water is transferred at 150 g / min, and the fibrous substance dispersion is transferred to the resin pipe with a pipe diameter of 10 mm, and the discharged material is received in the container. , The concentration and the supply amount (g / min) were measured every minute, and the supply amount stability and the concentration stability were evaluated according to the following criteria.
(Supply stability)
A: Pump is not clogged after 30 minutes of operation, and the standard deviation of supply is within 5%. B: Pump is not clogged after 30 minutes of operation, and the standard deviation of supply is more than 5% and 10%. Within C: The pump is clogged after 5 to 30 minutes of operation, or the standard deviation of the supply amount is more than 10% and within 50%. D: The pump is clogged in less than 5 minutes and cannot be operated (concentration stability).
A ... Concentration standard deviation within 5% B ... Concentration standard deviation over 5% and within 10% C ... Concentration standard deviation over 10% and within 30% D ... Concentration standard deviation Is over 30%

≪Preparation and evaluation of resin composition≫
The fibrous substance dispersion was stirred in a planetary mixer (Primix Corporation, trade name "Hibismix 2P-1") at 50 rpm, 10 minutes, 25 ° C., and atmospheric pressure, and then the jacket temperature was 80 ° C., −0. A dried fibrous substance was obtained by performing a vacuum drying treatment at 50 rpm for 8 hours under a reduced pressure condition of 1 MPa.

The obtained fibrous material and thermoplastic resin are melted under the following conditions at the ratios shown in Tables 1 and 2 using a twin-screw extruder (OMEGA30H manufactured by STEER, L / D = 60) having 13 cylinder blocks. The mixture was kneaded to obtain pellets of a fibrous material-reinforced thermoplastic resin.
(Melting and kneading conditions)
Rotation speed: 300 rpm
Cylinder temperature: 250 ° C (other than Example 35 and Comparative Example 15) or 200 ° C (for Example 35 and Comparative Example 15)

[Tensile yield strength, tensile yield elongation (TEy), tensile elongation at break (TEb)]
A multipurpose test piece compliant with ISO294-3 was molded using an injection molding machine with a maximum mold clamping pressure of 75 tons, and carried out at n = 10 under the conditions compliant with JIS K6920-2. Since the polyamide resin changes due to moisture absorption, it was stored in an aluminum moisture-proof bag immediately after molding to suppress moisture absorption.
The ratio [TEb / TEy] of the tensile yield elongation (TEy) and the tensile elongation at break (TEb) was calculated.

As is clear from Tables 1 and 2, the fibrous substance dispersions obtained in Examples 1 to 28 are fibrous substance dispersions containing a thickener, and the fibrous substances are highly dispersed. In addition to the dispersibility, the stability of the supply amount and supply concentration during pump transfer was excellent. On the other hand, in the fibrous substance dispersions of Comparative Examples 1 to 8, even if the fibrous substance has a low concentration, the supply amount and concentration at the time of transfer are not stable, clogging occurs in the pump, and the fibrous substance is present. When the concentration became high, it became impossible to send the liquid.

As is clear from Table 3, the fibrous material-reinforced thermoplastic resins obtained in Examples 29 to 40 suppress the aggregation of the fibrous material due to the water-retaining effect of the thickener, and the fibrous material is highly dispersed. Therefore, it was excellent in tensile strength and tensile elongation. On the other hand, the fibrous material-reinforced thermoplastic resins of Comparative Examples 9 to 15 had inferior tensile strength and tensile elongation as those of the examples due to insufficient dispersion of the fibrous material.

Since the fibrous substance dispersion liquid of the present disclosure can impart high strength to the resin molded product by highly dispersing the fibrous substance, it can be suitably used in fields such as automobile interior materials and exterior materials.

Claims (19)

With 100 parts by mass of dispersion medium,
0.01 to 20 parts by mass of fibrous material dispersed in the dispersion medium,
It is a fibrous substance dispersion liquid containing
The fibrous substance is a cellulose fiber,
The test dispersion prepared from the fibrous substance dispersion has the following formula (1):
α = 1-([A] / [B]) ... (1)
(In the formula (1), [A] is the height from the bottom surface of the dispersion liquid to the separation interface, and [B] is the height from the bottom surface of the dispersion liquid to the top surface of the dispersion liquid.)
The sedimentation degree α obtained according to the above is 80% or less.
When the concentration of the fibrous substance in the fibrous substance dispersion liquid is 0.05% by mass, the test dispersion liquid is the fibrous substance dispersion liquid itself, and the concentration is 0.05% by mass. If not, the fibrous substance dispersion is prepared by concentrating or diluting the fibrous substance dispersion with the same dispersion medium as the dispersion medium so that the concentration becomes 0.05% by mass. To 100 parts by mass of the dispersion medium, 0.0001 to 2 parts by mass of a thickener was further contained.
The fibrous material dispersion liquid according to claim 1, wherein the number average fiber diameter of the fibrous material is 1 to 1000 nm. The thickener is at least one selected from the group consisting of polyacrylamide, polyalkylene oxide, polyacrylic acid and salts thereof, cellulose derivatives, polyvinyl alcohol, propylene glycol, alginic acid and salts thereof, according to claim 2. The fibrous substance dispersion liquid described. The fibrous substance dispersion liquid according to any one of claims 1 to 3, wherein the surface of the fibrous substance is hydrophobic. The fibrous substance dispersion liquid according to any one of claims 1 to 4, wherein the fibrous substance is cellulose nanofibers. The fibrous form according to claim 5, wherein the cellulose nanofibers have a weight average molecular weight (Mw) of 100,000 or more and a ratio (Mw / Mn) of 6 or less of the weight average molecular weight (Mw) to the number average molecular weight (Mn). Material dispersion. The fibrous substance dispersion liquid according to claim 5 or 6, wherein the cellulose nanofibers have an average content of alkali-soluble polysaccharides of 12% by mass or less and a crystallinity of 60% or more. The fibrous substance dispersion according to any one of claims 5 to 7, wherein the average content of acid-insoluble components of the cellulose nanofibers is 10% by mass or less. The fibrous substance dispersion liquid according to any one of claims 1 to 8, wherein the dispersion medium is water. The fibrous substance dispersion liquid according to any one of claims 1 to 9, which contains a particulate component. The fibrous substance dispersion liquid according to claim 10, which is an emulsion. The fibrous substance dispersion liquid according to any one of claims 1 to 11, which contains a surfactant. A method for improving the liquid transfer property of a fibrous substance dispersion liquid containing a dispersion medium and a fibrous substance dispersed in the dispersion medium.
The method is
The test dispersion prepared from the fibrous substance dispersion has the following formula (1):
α = 1-([A] / [B]) ... (1)
(In the formula (1), [A] is the height from the bottom surface of the dispersion liquid to the separation interface, and [B] is the height from the bottom surface of the dispersion liquid to the top surface of the dispersion liquid.)
The fibrous material dispersion liquid contains a thickener so that the sedimentation degree α obtained according to the above is 80% or less.
When the concentration of the fibrous substance in the fibrous substance dispersion liquid is 0.05% by mass, the test dispersion liquid is the fibrous substance dispersion liquid itself, and the concentration is 0.05% by mass. If not, the method is prepared by concentrating the fibrous substance dispersion liquid or diluting it with the same dispersion medium as the dispersion medium so that the concentration becomes 0.05% by mass. A resin composition containing 100 parts by mass of a resin, 0.001 to 50 parts by mass of a fibrous substance having an average fiber diameter of 1 to 1000 nm, and 0.00001 to 5 parts by mass of a thickener. The resin composition according to claim 14, wherein the resin is a thermoplastic resin. The tensile yield elongation (TEy) and the tensile elongation at break (TEb) are the following relational expressions:
[TEb / TEy] ≧ 1
The resin composition according to claim 14 or 15. The resin according to any one of claims 14 to 16, wherein the tensile strength is improved by 1.01 times or more as compared with the comparative resin composition having the same composition except that the thickener is not contained. Composition. A method for producing a resin composition containing a thermoplastic resin and a fibrous substance.
To prepare the fibrous substance dispersion liquid according to any one of claims 1 to 12,
Melting and kneading the fibrous material dispersion and the thermoplastic resin,
Including methods. A method for producing a resin composition containing a thermoplastic resin and a fibrous substance.
To prepare the fibrous substance dispersion liquid according to any one of claims 1 to 12,
To prepare a dried product by drying the fibrous substance dispersion liquid,
Melting and kneading the dried product and the thermoplastic resin,
Including methods.

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