Powdery cellulose

Abstract

To provide a powdery cellulose which enhances tensile strength and flexural strength when formulated into a resin composition, and also exhibits superior flowability.SOLUTION: The present invention provides a powdery cellulose for a molding resin material, the powdery cellulose having a particle diameter D50 of 10-100 μm and an aspect ratio of 1.0-4.0. The powdery cellulose has a fiber length ratio of less than 20% as represented by the following formula (1). (1): Fiber length ratio=average fiber length of the powdery cellulose÷average fiber length of the raw pulp×100.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to powdery cellulose.

Background Art

[0002] In recent years, powdery cellulose has been used as a reinforcing agent for resin materials such as rubber and plastic (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As one of the uses of a resin composition containing powdery cellulose, it is used for appearance parts such as home appliance housings and interior and exterior parts of automobiles. The properties required for appearance parts include mechanical strengths such as tensile strength, bending strength, and impact strength, and fluidity of the resin is required during part molding. However, a resin composition containing general cellulose fibers has a problem of low fluidity.

[0005] The present invention has been made in view of the above, and an object thereof is to provide powdery cellulose that has improved tensile strength and bending strength and good fluidity when used as a resin composition.

Means for Solving the Problems

[0006] The present invention provides the following [1] to [7]. [1] Powdery cellulose for a molding resin material, having a particle size D50 of 10 to 100 μm and an aspect ratio of 1.0 to 4.0, wherein the fiber length ratio represented by the following formula (1) of the powdery cellulose is less than 20%, and the powdery cellulose for a molding resin material. (1): Fiber length ratio = average fiber length of powdered cellulose ÷ average fiber length of raw material pulp × 100 〔2〕The powdered cellulose for the molding resin material according to 〔1〕, wherein the fiber length of the powdered cellulose is 40 to 100 μm. 〔3〕The powdered cellulose for the molding resin material according to 〔1〕, wherein the value obtained by subtracting the particle size D50 from the particle size D90 of the powdered cellulose (particle size D90 - particle size D50) is 30 to 80 μm. 〔4〕The powdered cellulose for the molding resin material according to claim 1, wherein in the raw material pulp used for the powdered cellulose, the proportion of fibers having a fiber width greater than 20 μm is 20% or more. 〔5〕The powdered cellulose for the molding resin material according to 〔1〕, wherein the raw material pulp used for the powdered cellulose contains softwood bleached kraft pulp (NBKP). 〔6〕A molding resin material comprising the powdered cellulose and a thermoplastic resin. 〔7〕The molding resin material according to 〔6〕, wherein the content of the powdered cellulose is 10% by weight or more when the molding resin material is 100% by weight.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide powdered cellulose having improved tensile strength and flexural strength and good fluidity when made into a resin composition.

Modes for Carrying Out the Invention

[0008] 〔1. Powdered cellulose〕 The powdered cellulose has a predetermined average particle size and aspect ratio, and the fiber length ratio is less than 20%.

[0009] 〔1.1. Average particle size〕 〔Particle size distribution〕 The particle size distribution of powdered cellulose can be expressed as the particle size distribution (10% diameter, 50% diameter, 90% diameter, D.10, D.50, D.90, respectively) when the integrated value of the volume accumulation distribution is 10%, 50%, and 90%. In this specification, the particle size distribution is a value obtained by wet measurement (with ultrasonic irradiation) using the laser scattering method as the measurement principle. Note that the average particle size in this specification refers to the value of D.50 obtained by wet measurement (with ultrasonic irradiation).

[0010] -Wet measurement (with ultrasonic irradiation)- In this specification, the wet condition (with ultrasonic irradiation) refers to the condition where the particle size is measured after ultrasonic irradiation is performed on the sample after adding water. The preferred ranges of D.10, D.50, and D.90 in the case of wet (with ultrasonic) are as follows. Generally, the larger the particle size, the higher the tendency of entanglement between fibers. Furthermore, within the following ranges, the strength can be appropriately improved without impairing their properties when added to resins, rubbers, etc. D.10 is usually 3.0 μm or more, preferably 5.0 μm or more, and more preferably 10.0 μm or more. The upper limit is usually 20.0 μm or less, preferably 17.0 or less, and more preferably 15.0 μm or less. D.50 is usually 10.0 μm or more, preferably 20.0 μm or more, more preferably 25.0 μm or more, and even more preferably 30.0 μm or more (however, it is a value larger than D.10). The upper limit is usually 100.0 μm or less, preferably 80.0 μm or less, more preferably 60.0 μm or less, and even more preferably 50.0 μm or less. D.90 is usually 50.0 μm or more, preferably 65.0 μm or more, and more preferably 80.0 μm or more (however, it is a value larger than D.50). The upper limit is usually 150.0 μm or less, preferably 120.0 μm or less, and more preferably 100.0 μm or less.

[0011] The value obtained by subtracting the particle diameter D10 from the particle diameter D90 of the powdery cellulose of the present invention (particle diameter D90 - particle diameter D10) is preferably 40 to 100 μm, more preferably 50 to 90 μm, and even more preferably 60 to 90 μm. When the particle diameter D90 - particle diameter D10 is 400 to 100 μm, since the particle size distribution is appropriate, when kneaded with a resin to form a resin composition, the tensile strength and flexural strength can be improved while maintaining appropriate fluidity.

[0012] Also, the value obtained by subtracting the particle diameter D50 from the particle diameter D90 of the powdery cellulose of the present invention (particle diameter D90 - particle diameter D50) is preferably 30 to 80 μm, more preferably 40 to 70 μm, and even more preferably 50 to 70 μm. When the particle diameter D90 - particle diameter D50 is 30 to 80 μm, since the powder having a large particle size is appropriately contained, the tensile strength and flexural strength can be improved when kneaded with a resin.

[0013] Also, the value obtained by subtracting the particle diameter D10 from the particle diameter D50 of the powdery cellulose of the present invention (particle diameter D50 - particle diameter D10) is preferably 10 to 40 μm, more preferably 15 to 30 μm, and even more preferably 20 to 30 μm. When the particle diameter D50 - particle diameter D10 is 10 to 40 μm, since the powder having a small particle size is appropriately contained, appropriate fluidity can be maintained when kneaded with a resin.

[0014] [1.2. Average fiber width (μm), average fiber length (μm), average fiber length / average fiber width (L / D, aspect ratio) of powdery cellulose] The average fiber length of the powdery cellulose is preferably 40 to 100 μm, more preferably 50 to 90 μm. When the average fiber length is 40 to 100 μm, appropriate fluidity can be maintained when kneaded with a resin.

[0015] The average fiber width of the powdery cellulose is usually 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more. The upper limit is usually 50 μm or less, preferably 40 μm or less, more preferably 35 μm or less.

[0016] The average fiber length / average fiber width (L / D, aspect ratio) of the powdery cellulose is preferably 1.0 to 4.0, more preferably 2.0 to 4.0, and still more preferably 2.0 to 3.5. When a fibrous filler is added to a resin, the fluidity decreases and molding becomes difficult. However, when the L / D of the powdery cellulose is 2.0 to 4.0, when a resin composition containing the powdery cellulose is formed, the tensile strength and flexural strength are improved compared to the resin alone, and appropriate fluidity when forming the resin composition can also be maintained.

[0017] The average fiber length and average fiber width can be measured with a Fiber Tester Plus manufactured by ABB. In this specification, the average fiber length refers to the length-weighted fiber length when all fibers of 0.0 mm or more are the analysis target, and the average fiber width refers to the width-weighted fiber width. L / D is a value calculated from these measured values.

[0018] [[2.1. Cellulose raw material]] The cellulose raw material is usually naturally derived cellulose, preferably pulp, and more preferably wood-derived pulp. Examples of wood-derived pulp include softwood unbleached kraft pulp (NUKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), hardwood bleached kraft pulp (LBKP), softwood bleached dissolving kraft pulp (NDKP), hardwood bleached dissolving kraft pulp (LDKP), softwood unbleached sulfite pulp (NUSP), softwood bleached sulfite pulp (NBSP), hardwood unbleached sulfite pulp (LUSP), hardwood bleached sulfite pulp (LBSP) and other wood-derived pulps, thermomechanical pulp (TMP), pressure groundwood pulp (PGW), refiner groundwood pulp (RGP), alkaline hydrogen peroxide mechanical pulp (APMP), alkaline hydrogen peroxide thermomechanical pulp (APTMP), etc. Among them, softwood bleached kraft pulp (NBKP) and hardwood bleached kraft pulp (LBKP) are preferred as the material, and softwood bleached kraft pulp (NBKP) is more preferred. In the present invention, the reason why softwood bleached kraft pulp (NBKP) is preferred is that the fiber width of softwood bleached kraft pulp (NBKP) is longer than that of hardwood bleached kraft pulp (LBKP), and the aspect ratio of the pulp after pulverization is likely to be smaller.

[0019] Examples of the method for preparing wood-derived pulp include methods including treatment by a chemical pulping method (kraft method). By treatment by the chemical pulping method (kraft method), lignin, which is a coloring substance, is dissolved and removed, and high-whiteness pulp can be obtained by combining with oxygen delignification treatment and bleaching treatment. Examples of the chemical pulping method (kraft method) include the sulfite kraft method, the kraft method, the soda-quinone kraft method, and the organosolv kraft method. In terms of the environment and economy, kraft pulp is preferred. The kraft method is a method in which alkaline chemicals such as sodium hydroxide, potassium hydroxide, and sodium carbonate and chemicals containing sulfur such as sodium sulfide and sodium sulfite are used in combination, and quinone-based cooking aids, polysulfides, etc. can be used as additives. These additives do not need to be used if cooking can be performed with only alkaline chemicals.

[0020] In the method for preparing pulp, oxygen delignification treatment can be performed on the pulp obtained by cooking. The oxygen delignification used in the present invention can be directly applied with known medium-consistency or high-consistency methods. In the case of the medium-consistency method, it is preferably carried out at a pulp concentration of 8 to 15% by mass, and in the case of the high-consistency method, it is preferably carried out at 20 to 35% by mass. As the alkali in oxygen delignification, sodium hydroxide and potassium hydroxide can be used, and as the oxygen gas, oxygen from cryogenic separation, oxygen from PSA (Pressure Swing Adsorption), oxygen from VSA (Vacuum Swing Adsorption), etc. can be used. The reaction conditions for the oxygen delignification treatment are not particularly limited, but the oxygen pressure is 3 to 9 kg / cm 2 , more preferably 4 to 7 kg / cm 2The alkali addition rate is 0.5 to 4 mass %, the temperature is 80 to 140° C., the treatment time is 20 to 180 minutes, and other conditions that are known in the art can be applied. In the present invention, the oxygen delignification treatment may be carried out multiple times.

[0021] The pulp that has been subjected to the oxygen delignification treatment may then be sent to a washing step, and after washing, may be subjected to a bleaching treatment as described below. The brightness of the pulp that has been subjected to the oxygen delignification treatment is preferably 30% to 55% based on ISO 2470.

[0022] In the preparation of pulp, in addition to chemical pulping (cooking) and oxygen delignification, a bleaching treatment can also be carried out. This results in a pulp with a higher brightness. Examples of bleaching treatment methods include chlorine treatment (C), chlorine dioxide bleaching (D), alkaline extraction (E), hypochlorite bleaching (H), hydrogen peroxide bleaching (P), alkaline hydrogen peroxide treatment stage (Ep), alkaline hydrogen peroxide-oxygen treatment stage (Eop), ozone treatment (Z), chelate treatment (Q), and combinations of two or more of these treatments on pulp that has been delignified by any conventional method. Examples of combinations (sequences) of two or more treatments include DE / PD, C / DEHD, ZED-PZ / D-Ep-D, Z / D-Ep-DP, D-Ep-D, D-Ep-DP, D-Ep-PD, Z-Eop-DD, Z / D-Eop-D, and Z / D-Eop-DED (the " / " in the sequence means that the treatments before and after the " / " are performed consecutively without washing). The bleaching treatment is not limited to the above examples, and may be a commonly used method. Pulp that has been bleached is usually in a fluid state (fluid pulp).

[0023] The brightness of the pulp subjected to such bleaching treatment is preferably 70% or more based on ISO 2470.

[0024] The moisture content of the cellulose raw material is usually preferably 5 to 30%, more preferably 5 to 20% based on 100% of the cellulose raw material. When the moisture content of the cellulose raw material is more than the above range, the moisture content may be adjusted by the dehydration and drying treatment described below.

[0025] The average fiber length of the raw material pulp is preferably 500 to 3,000 μm, more preferably 600 to 2,000 μm. When the average fiber length is 500 to 3,000 μm, the aspect ratio tends to be small when pulverized into powdered cellulose.

[0026] The average fiber width of the raw material pulp is usually 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more. The upper limit is usually 50 μm or less, preferably 40 μm or less, more preferably 35 μm or less.

[0027] The proportion of fibers having a fiber width greater than 20 μm in the raw material pulp is preferably 20% or more, more preferably 40% or more, still more preferably 60% or more. By using a raw material pulp containing 20% or more of fibers having a fiber width greater than 20 μm, the L / D after pulverization tends to be small, and the fluidity of the resin composition containing powdered cellulose can be ensured.

[0028] In addition to the average fiber length and the average fiber width, the proportion of fibers having a fiber width greater than 20 μm can also be measured with the Fiber Tester Plus manufactured by ABB as described above. By obtaining the fiber width distribution when all fibers of 0.0 mm or more are analyzed with the Fiber Tester Plus and summing up the proportion of fibers having a fiber width greater than 20 μm, the proportion of fibers having a fiber width greater than 20 μm is calculated.

[0029] ​​The fiber length ratio of the powdery cellulose of the present invention is preferably less than 20%, more preferably less than 15%, and even more preferably less than 10%. When the fiber length ratio is less than 20%, the pulverization is appropriate, and when a resin composition containing powdery cellulose is obtained, appropriate fluidity can be maintained. Note that the fiber length ratio is calculated by the following formula (1). (1): Fiber length ratio = average fiber length of powdery cellulose ÷ average fiber length of raw material pulp × 100

[0030] [3. Method for producing powdery cellulose] The method for producing powdery cellulose is not particularly limited as long as it is a method for obtaining powdery cellulose from a cellulose raw material. For example, a method including at least a pulverization treatment can be mentioned, and a method including a mechanical pulverization treatment is preferable.

[0031] [Mechanical pulverization treatment] The pulverization treatment is a treatment for mechanically pulverizing a cellulose raw material. Prior to the pulverization treatment, pretreatment such as dehydration / drying treatment and acid hydrolysis treatment may be performed, and dehydration / drying treatment is preferable. Classification treatment may be performed simultaneously with or after the pulverization treatment.

[0032] Examples of the pulverizer include a cutting mill, an impact mill, a pneumatic mill, a hammer mill, a roll mill, a roller mill, a media mill, a media stirring mill, and a freeze pulverizer, and they may be used alone or in combination of two or more.

[0033] Examples of the cutting mill include a cutting mill (manufactured by Horai Co., Ltd.), a mesh mill (manufactured by Horai Co., Ltd.), Atoms (manufactured by Yamamoto Hyakuba Seisakusho Co., Ltd.), a knife mill (manufactured by Palman), a cutter mill (manufactured by Tokyo Atomizer Co., Ltd.), a centric cutter (manufactured by Nippon Coke Industry Co., Ltd.), a rotary cutter mill (manufactured by Nara Machinery Co., Ltd.), a turbo cutter (manufactured by Floyd Turbo Co., Ltd.), and a pulp crusher (manufactured by Zuiho Co., Ltd.).

[0034] Examples of hammer mills include, for example, Hammer Mill (manufactured by Hosokawa Micron Corporation), Joe Crusher (manufactured by Makino Corporation), and Hammer Crusher (manufactured by Mano Industries Co., Ltd.).

[0035] Examples of impact mills include, for example, Pulverizer (manufactured by Hosokawa Micron Corporation), Fine Impact Mill (manufactured by Hosokawa Micron Corporation), Super Micron Mill (registered trademark, manufactured by Hosokawa Micron Corporation), Inomizer (registered trademark, manufactured by Hosokawa Micron Corporation), Fine Mill (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), CUM Type Centrifugal Mill (manufactured by Mitsui Mining Co., Ltd.), Ixeed Mill (manufactured by Mano Industries Co., Ltd.), Ultra Plex (manufactured by Mano Industries Co., Ltd.), Contra Plex (manufactured by Mano Industries Co., Ltd.), Colo Plex (manufactured by Mano Industries Co., Ltd.), Atomizer (manufactured by Seishin Enterprise Co., Ltd.), Tornado Mill (manufactured by Nikkiso Co., Ltd.), Near Mill (manufactured by Dalton Co., Ltd.), Free Mill (manufactured by Nara Machinery Co., Ltd.), New Cosmomizer (manufactured by Nara Machinery Co., Ltd.), Turbo Mill (manufactured by Floyd Turbo Co., Ltd.), Super Powder Mill (manufactured by Nishimura Machinery Co., Ltd.), Blade Mill (manufactured by Nisshin Engineering Co., Ltd.), Super Rotor (manufactured by Nisshin Engineering Co., Ltd.), Wire Mill (manufactured by Sanki Manufacturing Co., Ltd.), Pulp Mill (manufactured by Zuiho Co., Ltd.), Jacobson Fine Mill (manufactured by Kobe Steel Pantech Co., Ltd.), Universal Mill (manufactured by Tokuju Kousakusho Co., Ltd.), and Continuous Vibro Mill (manufactured by Eurastech Co., Ltd.).

[0036] Examples of air classifying mills include, for example, CGS Type Jet Mill (manufactured by Mitsui Mining Co., Ltd.), Micron Jet (registered trademark, manufactured by Hosokawa Micron Corporation), Counter Jet Mill (registered trademark, manufactured by Hosokawa Micron Corporation), Cross Jet Mill (manufactured by Kurimoto Iron Works Co., Ltd.), Supersonic Jet Mill (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), Current Jet (manufactured by Nisshin Engineering Co., Ltd.), Jet Mill (manufactured by Mitsou Ind., Ltd.), Selen Miller (manufactured by Masayuki Sangyo Co., Ltd.), New Micro Cyclotmat (manufactured by Masuno Manufacturing Co., Ltd.), and Crypton (manufactured by Earth Technica Co., Ltd.).

[0037] Examples of roller mills include vertical roller mills (manufactured by Seishin Co., Ltd.), vertical roller mills (manufactured by Shinion Co., Ltd.), roller mills (manufactured by Kotobuki Giken Kogyo Co., Ltd.), VX mills (manufactured by Kurimoto Iron Works, Ltd.), KVM type vertical roller mills (manufactured by Earth Technica Co., Ltd.), and IS mills (manufactured by IHI Plant Engineering Co., Ltd.). Among these, cutting mills and roller mills are preferred.

[0038] The conditions for the pulverization treatment can be appropriately set so as to obtain the desired powdered cellulose. For example, the treatment conditions can be adjusted by referring to a calibration curve created from the pulverization conditions (e.g., treatment time, input amount) and the desired physical properties of the powdered cellulose.

[0039] - Neutralization, washing, dehydration, and drying treatment - The cellulose raw material is appropriately pretreated before the pulverization treatment. Examples of the pretreatment include neutralization, washing, liquid removal, and drying treatment, and it is preferable to perform the dehydration and drying treatments in this order. The cellulose raw material can adjust the solid content concentration by the drying (dehydration) treatment, and it is easy to control the physical property values of the powdered cellulose.

[0040] - Acid hydrolysis treatment - Examples of the acid used for the acid hydrolysis treatment include mineral acids such as hydrochloric acid, sulfuric acid, and nitric acid. The acid concentration is not particularly limited, but from the viewpoints of maintaining the degree of polymerization and whiteness, it is preferably lower than the acid concentration in the conventional acid hydrolysis treatment for manufacturing powdered cellulose, more preferably 0.4 to 2.0 N, and even more preferably 0.5 to 1.5 N. When the acid concentration is less than 0.4 N, the depolymerization of cellulose by the acid is suppressed, and the decrease in the degree of polymerization of cellulose can be reduced, but it may be difficult to achieve fine particle size. On the other hand, when it exceeds 2.0 N, the depolymerization of cellulose proceeds and fine particle size is easily achieved, so the powder fluidity is improved, but the tablet hardness may decrease due to the decrease in the degree of polymerization (when molded, it may be easily disintegrated). The reaction conditions for the acid hydrolysis treatment are not particularly limited, but the reaction temperature is usually 80 to 100°C, and the reaction time is usually 30 minutes to 3 hours.

[0041] Prior to the acid hydrolysis treatment, pretreatment may be performed on the cellulose raw material. For example, slurrying of the cellulose raw material (preparation of a dispersion), adjustment of the cellulose raw material concentration can be mentioned. The concentration of the cellulose raw material is usually 3 to 10% by weight (in terms of solid content) with respect to the dispersion. When the cellulose raw material is a bleached fluid pulp, usually, a treatment to increase the pulp concentration is often performed before hydrolysis. For the adjustment (concentration) of the cellulose raw material concentration, a dehydrator such as a screw press or a belt filter may be used. The acid hydrolysis treatment may be performed on the slurry of the cellulose raw material, or may be performed on the sheet-like cellulose raw material. When the cellulose raw material is a dry sheet of pulp, usually, the pulp is loosened and then the acid hydrolysis treatment is performed. When loosening the pulp, a crusher such as a roll crusher may be used.

[0042] During the pulverization treatment after acid hydrolysis, if necessary, at least one other component (for example, an organic component, an inorganic component) may be subjected to the pulverization treatment together with the acid hydrolysis treatment product. Thereby, functionality can be imparted to the powdered cellulose or the functionality can be improved. The blending amount of the other component may be appropriately selected as an appropriate amount. Further, prior to the pulverization step, the above-mentioned neutralization, washing, dehydration, and drying treatments may be further performed on the acid hydrolysis treatment product.

[0043] The powdered cellulose may be subjected to a chemical treatment if necessary. The chemical treatment is preferably a treatment that does not significantly impair the degree of polymerization of the cellulose raw material. The timing of the chemical treatment may be performed during the pulverization treatment of the cellulose raw material, or may be performed before the pretreatment of the pulverization treatment.

[0044] [4. Uses of Powdered Cellulose] As uses of other powdered celluloses, for example, they can be used as industrial additives (for example, for resins such as polypropylene, phenol resin, melamine resin, etc., for various rubbers). Also, they can be used as components and raw materials of resin compositions (for example, polyolefin resins, modified polyolefin resins, rubbers), rubber compositions (for example, automobiles, personal computers, building materials, containers), etc.

[0045] The powdered cellulose of the present invention can be particularly used as a resin material for molding. By using the powdered cellulose of the present invention in a resin material for molding, the tensile strength and flexural strength can be improved, and a certain degree of fluidity can also be maintained.

[0046] When the powdered cellulose of the present invention is used for a resin material for molding, although there is no particular limitation, the content of the powdered cellulose can be 10% by weight or more when the resin material for molding is 100% by weight. Further, since the fluidity of the resin material for molding is good due to the effect of the present invention, the content of the powdered cellulose can be 20% by weight or more, 50% by weight, 60% by weight or more.

Examples

[0047] Hereinafter, the present invention will be described by way of examples. The following examples do not limit the present invention. The test methods in the examples of this application are shown below. The measurement methods for physical property values and the like are the measurement methods described above unless otherwise specified.

[0048] <Average particle size> A laser diffraction particle size distribution measuring device (Mastersizer 3000, Malvern Panalytical Limited, Malvern, UK) was used. Using the laser scattering method as the measurement principle, the particle size distribution was measured by wet measurement (with ultrasonic irradiation). When the particle size distribution was expressed as a volume accumulation distribution, the values at which the integrated values of the volume accumulation distribution were 10%, 50%, and 90% were defined as the particle size distribution D.10, D.50, and D.90, respectively. The D.50 of wet measurement (with ultrasonic irradiation) was taken as the average particle size.

[0049] For wet measurement, the sample was added to the measurement part in water stirred at 3000 rpm so that the scattering intensity was about 10%. When ultrasonic waves were irradiated, ultrasonic waves were applied to the sample in water based on the following conditions and then wet measurement was performed. · Mode: Continuous · Intensity: 100% · Time: 600 seconds

[0050] The analysis of the particle size distribution was carried out under the following conditions for all measurement conditions. ·Analysis: General purpose ·Analysis sensitivity: Emphasis ·Light scattering model: Mie theory

[0051] <Average fiber length (μm), average fiber width (μm), L / D (aspect ratio)> The average fiber length and average fiber width of the raw pulp and powdered cellulose were measured using an L&W Fiber Tester Plus (manufactured by ABB) according to the following procedure. 0.1 g of the sample was placed in a cylinder containing 200 ml of pure water, stirred for about 1 minute, then transferred to a dedicated 300 ml beaker, set in a sample cycler, and measurement was started. Measurement was carried out until more than 55,000 fibers with a fiber length of 0.1 mm or more were counted. The length-weighted fiber length and width-weighted fiber width were obtained and taken as the average fiber length and average fiber width of the sample. In addition, on the Sample type screen for determining the measurement conditions, the Max value of Fines Limit was set to 0.0 and the Min value of Length class1 was set to 0.001 before measurement. The obtained average fiber length was divided by the average fiber width to calculate the L / D (aspect ratio).

[0052] <Ratio (%) of fibers with a fiber width greater than 20 μm> For the raw pulp, measurement was carried out using an L&W Fiber Tester Plus (manufactured by ABB) in the same manner as the measurement of the average fiber length and average fiber width above. The data of the fiber width distribution displayed on the Standard report screen was obtained, and the ratio of fibers with a width greater than 20 μm was calculated by summing.

[0053] <Fiber length ratio (%)> The fiber length ratio was calculated by the following formula (1). (1): Fiber length ratio = average fiber length of powdered cellulose ÷ average fiber length of raw pulp × 100

[0054] For the tensile strength, flexural strength, Charpy impact strength, and melt flow rate (MFR) of Examples 1 to 3 and Comparative Examples 1 to 4, evaluations were conducted using the following methods.

[0055] <Preparation of Resin Composition and Test Specimens> Powdered cellulose, polypropylene resin (BC10HRF, manufactured by Nippon Polypropylene Corporation), and maleic anhydride-modified polypropylene (Yumex 1010, manufactured by Sanyo Chemical Industries, Ltd.) were weighed in a ratio of 51:48.5:0.5 to a total of 8 g, and eight sets of these were prepared. Each 8-g portion of the weighed materials was charged into a small kneader ("MC15" manufactured by Xplore Instruments), kneaded at a temperature of 200°C for 5 minutes, and then, using an Xplore injection molding machine (manufactured by Xplore Instruments), five dumbbell-shaped test specimens (Type A12, JIS K7139) and eight strip-shaped test specimens (Type B1, JIS K7139) were molded under the conditions of a cylinder temperature of 200°C and a mold temperature of 40°C. Similarly, 25 g of the resin composition kneaded at 200°C for 5 minutes in the small kneader was collected for MFR measurement.

[0056] <Tensile Strength (MPa)> Regarding the obtained dumbbell-shaped test specimens, using a precision universal testing machine ("Autograph AG-Xplus" manufactured by Shimadzu Corporation), in accordance with JIS K 7161: Plastics - Test Method for Tensile Properties, the tensile stress was measured at a test speed of 1 mm / min and an initial gauge length of 30 mm, and the maximum value was taken as the tensile strength. The average value of the tensile strengths of the five test specimens was taken as the tensile strength of the sample. The tensile strength of the resin (BC10HRF) alone was 19.2 MPa.

[0057] <Flexural Strength (MPa)> Regarding the obtained strip-shaped test specimens, using a precision universal testing machine ("Autograph AG-Xplus" manufactured by Shimadzu Corporation), in accordance with JIK 7171, a flexural test was conducted with a support span of 64 mm and a test speed of 10 mm / min, and the maximum flexural stress that the test specimen could withstand during the flexural test was taken as the flexural strength. The average value of the flexural strengths of the three test specimens was taken as the flexural strength of the sample. The flexural strength of the resin (BC10HRF) alone was 28.5 MPa.

[0058] <Charpy impact strength (kJ / m 2 )> For the obtained strip-shaped test pieces, a Charpy impact test was carried out using a Charpy impact tester (model: IT, manufactured by Toyo Seiki Seisakusho Co., Ltd.). A notch with a depth of 2 mm was inserted into the center of the test piece. The pendulum of JC005J (0.5 J) was used to strike the side opposite the notch, and the impact strength was calculated. The average value of the Charpy impact strengths of 5 test pieces was taken as the Charpy impact strength of the said sample.

[0059] <MFR (g / 10 min)> The melt flow rate (MFR) of the obtained resin composition was measured using a melt flow indexer (G-02, manufactured by Toyo Seiki Seisakusho Co., Ltd.) under the conditions of a measurement temperature of 230 °C and a test load of 2.16 kg in accordance with JIS K7210.

[0060] <Preparation of powdered cellulose> (Example 1) Using a bleached kraft pulp sheet derived from hardwood (LBKP dry sheet, manufactured by Nippon Paper Industries Co., Ltd., moisture content 6.9%), the sheet was roughly crushed with a uniaxial crusher, and then primary crushed with a vertical roller mill (manufactured by Hatsuratsu Co., Ltd.) at a supply rate of 30 kg / h, a classifier frequency of 22 Hz, and a crushing roller frequency of 55 Hz. Then, secondary crushing was carried out with the same apparatus at a supply rate of 50 kg / h, a classifier frequency of 43 Hz, and a crushing roller frequency of 55 Hz to obtain powdered cellulose 1 with a moisture content of 1.9%.

[0061] (Example 2) Using a sun-dried kraft pulp sheet derived from coniferous trees (NBKP dry sheet, manufactured by Nippon Paper Industries Co., Ltd., moisture content 11.6%) as a raw material, after coarsely pulverizing it with a cutting mill (PI-20120, manufactured by Horai Co., Ltd., screen diameter Φ3 mm), the pulverized material obtained by pulverizing it with a cutting mill (HA8-2542, manufactured by Horai Co., Ltd., main mesh: 165 mesh, auxiliary mesh: 20 mesh) was further pulverized with a vertical roller mill (manufactured by Hatsuratsu Co., Ltd.) at a supply rate of 40 Kg / h, a classifier frequency of 45 Hz, and a pulverizing roller frequency of 55 Hz to obtain powdery cellulose 2 with a moisture content of 3.1%.

[0062] (Example 3) Using a sun-dried kraft pulp sheet derived from coniferous trees (NBKP dry sheet, manufactured by Nippon Paper Industries Co., Ltd., moisture content 10%) as a raw material, after coarsely pulverizing the sheet with a single-shaft crusher, it was first pulverized with a vertical roller mill (manufactured by Hatsuratsu Co., Ltd.) at a supply rate of 30 Kg / h, a classifier frequency of 14 Hz, and a pulverizing roller frequency of 55 Hz, and then secondarily pulverized with the same apparatus at a supply rate of 45 kg / h, a classifier frequency of 28 Hz, and a pulverizing roller frequency of 55 Hz to obtain powdery cellulose 3 with a moisture content of 3.5%.

[0063] (Comparative Example 1) Using a sun-dried kraft pulp sheet derived from broad-leaved trees (LBKP dry sheet, manufactured by Nippon Paper Industries Co., Ltd., moisture content 6.9%) where 35% is acacia wood as a raw material, after coarsely pulverizing it with a cutting mill (PI-20120, manufactured by Horai Co., Ltd., screen diameter Φ3 mm), it was pulverized with a cutting mill (HA8-2542, manufactured by Horai Co., Ltd., main mesh: 165 mesh, auxiliary mesh: 20 mesh) to obtain powdery cellulose 4 with a moisture content of 2.6%.

[0064] (Comparative Example 2) The same treatment as in Comparative Example 1 was carried out except that a sun-dried kraft pulp sheet derived from broad-leaved trees (LBKP dry sheet, manufactured by Nippon Paper Industries Co., Ltd., moisture content 4.4%) where 70% is acacia wood was used as a raw material, to obtain powdery cellulose 5 with a moisture content of 2.3%.

[0065] (Comparative Example 3) Using a hardwood-derived air-dried kraft pulp sheet (LBKP dry sheet, manufactured by Nippon Paper Industries Co., Ltd., moisture content 6.6%), the sheet was coarsely pulverized with a uniaxial crusher, and then pulverized with a vertical roller mill (manufactured by Hatsuratsu Co., Ltd.) at a supply rate of 52 kg / h, a classifier frequency of 50 Hz, and a pulverizing roller frequency of 55 Hz to obtain powdery cellulose 6 with a moisture content of 3.5%.

[0066] (Comparative Example 4) Using a hardwood-derived air-dried sulfite pulp sheet (LDPT dry sheet, manufactured by Nippon Paper Industries Co., Ltd., moisture content 6.2%) as a raw material, except that the mesh during pulverization with a cutting mill (HA8-2542) was set to 50 mesh, the same treatment as in Comparative Example 2 was performed to obtain powdery cellulose 7 with a moisture content of 5.5%.

[0067] [Table 1]

[0068] In Examples 1 to 3 where the particle size and aspect ratio were within a predetermined range and the fiber length ratio was less than 20%, the tensile strength and flexural strength were improved compared to the resin alone, and compared to Comparative Examples 1 to 4, the fluidity (MFR) when made into a resin composition was good.

Claims

1. Powdery cellulose for a molding resin material, having a particle size D50 of 10 to 100 μm and an aspect ratio of 1.0 to 4.0, wherein the fiber length ratio represented by the following formula (1) of the powdery cellulose is less than 20%. (1): Fiber length ratio = average fiber length of powdery cellulose ÷ average fiber length of raw pulp × 100

2. The powdery cellulose for a molding resin material according to Claim 1, wherein the fiber length of the powdery cellulose is 40 to 100 μm.

3. The powdery cellulose for a molding resin material according to Claim 1, wherein the value obtained by subtracting the particle size D50 from the particle size D90 of the powdery cellulose (particle size D90 - particle size D50) is 30 to 80 μm.

4. The powdery cellulose for a molding resin material according to Claim 1, wherein, in the raw pulp used for the powdery cellulose, the proportion of fibers having a fiber width greater than 20 μm is 20% or more.

5. The powdery cellulose for a molding resin material according to Claim 1, wherein the raw pulp used for the powdery cellulose contains softwood kraft pulp (NBKP).

6. A molding resin material comprising the powdery cellulose and a thermoplastic resin.

7. The molding resin material according to Claim 6, wherein the content of the powdery cellulose is 10% by weight or more when the molding resin material is 100% by weight.

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