JP5621219B2 - Method for producing cellulose fiber-containing resin composite material and method for producing resin molded body using the same - Google Patents

Description

The present invention relates to a method of manufacturing a resin molded body using the manufacturing side Ho及 Bikore cellulose fiber-containing resin composite material.

  BACKGROUND ART Fiber reinforced composite materials whose strength and rigidity are greatly improved by blending various fibrous reinforcing materials with resins are widely used in industrial fields such as electric / electronics, machinery, automobiles, and building materials.

  As the fibrous reinforcing material blended in the fiber-reinforced composite material, glass fibers having excellent strength and lightness are mainly used. However, although the glass fiber reinforced material can achieve high rigidity, the specific gravity is increased, so that there is a limit to weight reduction.

  On the other hand, fiber reinforcement made of organic materials such as polyester fiber, polyamide fiber, and aramid fiber has been studied as a fibrous reinforcement, but fiber reinforcement materials containing these reinforcements are lightweight and thermal recyclable. However, there was a problem that the mechanical reinforcement effect was not sufficient.

  On the other hand, in recent years, high-performance materials using plant-derived materials have attracted attention from the viewpoint of carbon neutrality. Fibers obtained by fibrillating cellulose fibers and mixing them with resin as fibrous reinforcements Composite materials have been proposed.

  In order to disperse these fibers uniformly in the resin and to make a highly functional material, the fibers must be microfibrillated and made uniform.

  As a method for microfibrillation, for example, Patent Document 1 describes a production method in which cellulose is wet-pulverized with water or a solvent. However, wet pulverization only describes an example in which water is used, and an organic solvent is used. There is no description of how to use it. In addition, the aqueous suspension of microfibrillated cellulose fibers is in a gel-like or wet flour state and cannot be said to be a uniform dispersion.

  Patent Document 2 describes a method of dispersing microfibrillated cellulose in an organic solvent, but water is used in the pulverization step for microfibrillating cellulose. For this reason, since the microfibrillated cellulose dispersed in the organic solvent contains water, it aggregates during the surface treatment of the cellulose or mixing with the resin.

JP 2008-248441 A JP 2008-24795 A

  Conventionally, when pulverizing cellulose into microfibrillated cellulose (MFC), water has been used, and as the MFC becomes smaller due to hydrogen bonds acting between cellulose and water, the slurry becomes gelled. It was a difficult problem to raise the concentration of the dispersion at the same time as producing a uniform dispersion.

The problem to be solved by the present invention is to produce a cellulose fiber-containing resin composite material using a cellulose fiber dispersion liquid which is pulverized into MFC at a high concentration and made into a uniform dispersion state without gelling cellulose. is there. In addition, a cellulose fiber-containing resin composite material is produced using a cellulose fiber dispersion that maintains a uniform dispersion state even when mixed with a resin, improves the mechanical strength of the resin, and does not impair the transparency. It is providing the manufacturing method of the resin molding which uses a fiber containing resin composite material .

  The object of the present invention is achieved by the following configurations.

1. Without adding water , cellulose fibers were pulverized to an average fiber diameter of 2 nm or more and 200 nm or less by an wet pulverization method in an organic solvent that is a solvent for dissolving and dispersing a matrix resin, and the cellulose fibers were uniformly dispersed in the organic solvent. Thereafter, the matrix resin is dissolved , cellulose fibers are dispersed in the organic solvent, and the matrix resin is dissolved, and then the organic solvent is removed. Production method.

2. A method for producing a resin molded article, comprising producing a resin molded article using the cellulose fiber-containing resin composite material produced by the method for producing a cellulose fiber-containing resin composite material according to item 1.

3. The method for producing a resin molded body according to item 2, wherein the resin molded body is formed in a film shape .

  According to the embodiment of the present invention, the cellulose fiber dispersion can be uniformly dispersed at a high concentration without gelation, and the microfibrillated cellulose can be uniformly dispersed in a transparent resin. As a result, mixing with the matrix resin was facilitated, and the mechanical properties such as tensile strength and low linear expansion of the polymer film or polymer composite could be greatly improved while maintaining the transparency of the resin.

  Conventionally, it has been considered that cellulose derived from natural products is hydrophilic and agglomerates in an organic solvent and cannot be dispersed. This invention discovered that the fiber diameter of a cellulose can be disperse | distributed in a common organic solvent by wet-pulverizing the fiber diameter of a cellulose with an organic solvent to the nanoscale microfibril.

  Hereinafter, although this invention is demonstrated based on embodiment, this invention is not limited to these.

(Cellulose fiber)
Examples of the raw material cellulose fiber used in the present invention include plant-derived pulp, wood, cotton, hemp, bamboo, cotton, kenaf, hemp, jute, banana, coconut, seaweed, tea leaves, and other fibers separated from plant fibers, marine animals Examples include fibers separated from animal fibers produced by sea squirts, and bacterial cellulose produced from acetic acid bacteria. Among these, fibers separated from plant fibers can be preferably used, but fibers obtained from plant fibers such as pulp and cotton are more preferable.

  Further, since hard materials such as wood cannot be directly processed using a homogenizer, a grinder, or the like, it is preferable to perform wet pulverization after pulverization with a dry pulverizer as pre-crushing.

(About organic solvents)
Any organic solvent that can disperse cellulose fibers may be used as long as the fibers can be dispersed in the solvent. Alcohols such as methanol, ethanol, 2-propanol, ketones such as acetone, methyl ethyl ketone, methyl butyl ketone, cyclohexanone, ethers such as tetrahydrofuran and diethyl ether, aromatic hydrocarbons such as toluene and xylene, Halogenated hydrocarbons can be used. These solvents can be used alone or in combination of two or more. Preferred are ketones.

(Wet grinding method)
In the present invention, these fibers are microfibrillated by a grinder, a high speed mixer, a homogenizer, a high speed impact mill, a Banbury mixer, a homomixer, a kneader, a ball mill, a vibration ball mill, a planetary ball mill, an attritor, a sand mill, a bead mill, and a colloid mill. , Using a jet mill, a roller mill, a tron mill, a high-speed stone mill, a high-pressure homogenizer, etc., and mechanically pulverizing cellulose fibers together with the organic solvent described above to obtain finely divided microfibril cellulose fibers. As long as the cellulose maintains the fiber state, there is no restriction on the defibrating method.

  The concentration at the time of defibration can be 0.1% by mass or more and 50% by mass or less with respect to the organic solvent, and preferably 0.5% by mass or more and 30% by mass or less.

  In particular, in order to achieve dispersion within an average fiber diameter of 10% or less, the following high shear mechanical pulverization method is preferable.

<High shear mechanical grinding method 1>
From the viewpoint of reducing the fiber diameter, a media disperser is preferable, and mills such as a ball mill, a sand mill, and a bead mill can be specifically mentioned. These dispersers may be arranged in series and dispersed in one pass, and there may be a storage process or the like between the first and second units.

  Distributing in one pass by arranging in series means that material is introduced from the sample inlet of one disperser, and the dispersion liquid that has come out from the outlet is not stored in a stock tank or the like, but is stored in the sample inlet of the next disperser. Indicates that they are connected directly or via piping. This simplifies the process, reduces adhesion loss in the process, and has many advantages as a production process.

  When these dispersers are arranged in series and operated continuously in one pass, there is considerable heat generation, so a heat exchanger is placed before or after the disperser or between the disperser and disperser. It is preferable to adjust the temperature. There is also a method of preventing heat generation by cooling in a storage tank between the first and second units.

  As the media of the media disperser preferably used in the present invention, beads of 1 mm or less, preferably 0.5 mm or less, more preferably 0.3 mm or less are preferable. Ceramic beads are preferred as the beads.

  When two or more media dispersers are arranged in series, it is preferable that the front disperser uses beads having a larger particle size as the bead particle size of the front and rear dispersers.

Examples of ceramics used for the ceramic beads used in the media disperser include, for example, Al ₂ O ₃ , BaTiO ₃ , SrTiO ₃ , MgO, ZrO, BeO, Cr ₂ O ₃ , SiO ₂ , SiO ₂ —Al ₂ O _3. , Cr ₂ O ₃ —MgO, MgO—CaO, MgO—C, MgO—Al ₂ O ₃ (spinel), SiC, TiO ₂ , K ₂ O, Na ₂ O, BaO, PbO, B ₂ O ₃ , SrTiO ₃ (strontium _{titanate), BeAl 2 O 4, Y} 3 Al 5 O 12, ZrO 2 -Y 2 O 3 ( cubic _{zirconia), 3BeO-Al 2 O 3} -6SiO 2 ( synthesis emerald), C (diamond) Si ₂ O—nH ₂ O, silicon nitride, yttrium stabilized zirconia, zirconia reinforced alumina, and the like are preferable. Yttrium-stabilized zirconia and zirconia-reinforced alumina (ceramics containing these zirconia are hereinafter abbreviated as zirconia) are particularly preferably used because of the low generation of impurities due to friction with beads and dispersers during dispersion.

<About high shear mechanical grinding method 2>
As a high-shear mechanical pulverization method, a pulverization method in which fine dispersion is performed by pressurizing the dispersion liquid at a high pressure to pass through a fine slit and then causing a rapid pressure drop can be preferably exemplified. In general, (a) “shearing force” generated when the dispersoid passes through a narrow gap (about 75 μm to 350 μm) at high pressure and high speed, and (b) liquid-liquid collision or wall collision in a narrow space with high pressure. It is considered that uniform and efficient dispersion is performed by further increasing the cavitation force due to the subsequent pressure drop without changing the generated impact force. Dispersing devices using this type of pulverization method have long been known as gorin homogenizers. However, in this device, the liquid to be dispersed sent at a high pressure is converted into a high-speed flow through a narrow gap on the cylindrical surface, It collides with the wall surface and emulsifies and disperses by the impact force. Examples of the liquid-liquid collision include a Y-type chamber of a microfluidizer, a spherical chamber using a spherical check valve as described in JP-A-8-103642, and the liquid-wall collision includes Examples include a Z-type chamber of a microfluidizer. In order to increase the dispersion efficiency, a device that has been devised such as making the high-speed flow part into a saw blade shape and increasing the number of collisions has been devised. Typical examples of such devices include Gorin homogenizers, microfluidizers manufactured by Microfluidics International Corporation, microfluidizers manufactured by Mizuho Industry Co., Ltd., nanomizers manufactured by Special Machine Industries, Inc., and Sugino Machine High pressure crushing system “Ultimizer HJP-25005”, etc. Further, there are also descriptions in JP-A-8-238848, JP-A-8-103642, and US Pat. No. 4,533,254.

  The degree of dispersion is not particularly limited as long as the average fiber diameter is 2 nm or more and 200 nm or less, but the average fiber diameter dispersion is preferably within 30%, particularly preferably the dispersion is 10% or less. It is also preferable in terms of tensile strength, transmittance and the like.

(Average fiber diameter)
The cellulose fiber of the present invention only needs to be defibrated to an average fiber diameter of 2 nm or more and 200 nm or less, and the fiber surface may be further subjected to surface treatment by chemical modification or physical modification.

(About measuring method of average fiber diameter and degree of dispersion)
Specifically, the standard deviation of the average fiber diameter can be known by the following procedure. First, a microfibrillated cellulose film coated on a support is attached to an appropriate holder with an adhesive, and an ultrathin film having a thickness of 0.1 to 0.2 μm is used with a diamond knife in a direction substantially parallel to the support surface. Make sections. At this time, the upper and lower ends of the microfibrillated cellulose film are observed with an optical microscope to confirm that the cutting is performed substantially parallel to the support surface, that is, the cutting angle is 1 degree or less.

  The prepared ultrathin slice was supported on a copper mesh, transferred onto a carbon film that had been hydrophilized by glow discharge, and cooled to −130 ° C. or lower with liquid nitrogen, while being subjected to a transmission electron microscope (hereinafter referred to as TEM). Thus, a bright field image is observed at a magnification of 5,000 to 40,000, and the image is quickly recorded on a film, an imaging plate, a CCD camera or the like. At this time, it is preferable to appropriately select a portion where the section is not torn or slack as an observed visual field.

  As the carbon film, it is preferable to use a film supported by an organic film such as a very thin collodion or form bar, and more preferably, the carbon film is formed on a rock salt substrate and dissolved and removed, or the organic film is formed of an organic film. It is a carbon-only film obtained by solvent and ion etching.

  The acceleration voltage of TEM is preferably 80 to 400 kV, particularly preferably 80 to 200 kV.

  In addition, for details of electron microscope observation techniques and sample preparation techniques, see “The Electron Microscopy Society of Kanto Branch / Medical and Biological Electron Microscopy” (Maruzen), “The Electron Microscopy Society of Kanto Branch / Electron Microscope Biological Samples” "Manufacturing method" (Maruzen) can be referred to respectively.

  A TEM image recorded on a suitable medium is preferably decomposed into at least 1024 pixels × 1024 pixels, preferably 2048 pixels × 2048 pixels or more, and image processing by a computer is performed.

  In order to perform image processing, it is preferable that an analog image recorded on a film is converted into a digital image by a scanner or the like, and shading correction, contrast / edge enhancement, and the like are performed as necessary. Thereafter, a histogram is prepared, and a portion corresponding to microfibrillated cellulose that is 2 nm or more and 200 nm or less is extracted from the image by binarization processing. Inevitably, the aggregated particles are cut by an appropriate algorithm, and particles having an equivalent circle diameter (HEYWOOD) of less than 2 nm are deleted (ELIMINATE). Next, the center point of each particle is obtained (SHLINK), and each pixel is expanded (EXTEND) by the center point until it touches each other to form a cell around the center point. At this time, the cell that has taken the measurement frame is deleted (EDGEPROCESS REJECT), and the equivalent circle diameter (HEYWOOD) of each cell is obtained. Similarly, an average value and a standard deviation are calculated from values obtained for at least 500, preferably 1000 or more cells, and the degree of dispersion is obtained by the following equation.

Dispersity = (standard deviation of equivalent circle diameter of cell) / (average value of equivalent circle diameter of cell) × 100
When performing the measurement according to the above procedure, it is preferable to sufficiently perform the length correction (scale correction) per pixel and the two-dimensional distortion of the measurement system in advance using a standard sample. Uniform latex particles (DULP) marketed by US Dow Chemical Company are suitable as the standard sample, and polystyrene particles having a coefficient of variation of less than 10% for a particle size of 0.1 to 0.3 μm are used. Specifically, a lot having a particle size of 0.212 μm and a standard deviation of 0.0029 μm is available.

  The details of the image processing technology can be referred to "Hiroshi Tanaka image processing applied technology (Industry Research Committee)", and the image processing program or device is not particularly limited as long as the above operation is possible, An example is Lulex-III manufactured by Nireco.

(Matrix resin)
Next, the matrix resin used in the present invention will be described.

  Examples of the matrix resin include the following materials that are generally used as general-purpose plastics that are commercially available. Polyethylene (PE), high density polyethylene, medium density polyethylene, low density polyethylene, polypropylene (PP), polyvinyl chloride (PVC), polyvinylidene chloride, polystyrene (PS), polyvinyl alcohol (PVA), polyvinyl acetate (PVAc) , Teflon (registered trademark) (polytetrafluoroethylene, PTFE), ABS resin (acrylonitrile butadiene styrene resin), AS resin, acrylic resin (PMMA), and the like.

  When strength and resistance to breakage are particularly required, the following may be mentioned.

  Polyamide (PA), nylon, polyacetal (POM), polycarbonate (PC), modified polyphenylene ether (m-PPE, modified PPE, PPO), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), glass fiber reinforced polyethylene terephthalate ( GF-PET) and cyclic polyolefin (COP).

  In the case where higher heat distortion temperature and long-term use characteristics are required, the following can be mentioned. Polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), polysulfone, polyethersulfone, amorphous polyarylate, liquid crystal polymer, polyetheretherketone, thermoplastic polyimide (PI), polyamideimide (PAI), etc. .

  Although these general resins are abundant in types, there are many commercially available products of the same type and different molecular weights, so combinations of types and molecular weights should be performed according to the application of the present invention. Is possible.

  Particularly preferred thermoplastic resins include polyethylene terephthalate (PET), polycarbonate (PC), and acrylic resin (PMMA).

(Method for producing cellulose fiber-containing resin material)
As a method for producing the cellulose fiber-containing resin material of the present invention, one type of cellulose fiber or one or more types of cellulose fibers are uniformly dispersed in an organic solvent, and then the matrix resin is dissolved, and the film is obtained by a solvent casting method. There is a way to make it.

  In addition, in the case of mixing with a resin that does not dissolve in a solvent, the cellulose fiber dispersion is dried once by a drying method that does not aggregate, such as freeze drying, and then a powder is added to the molten resin to form a molded body However, it is sufficient that the cellulose fiber and the matrix resin can be mixed, and the mixing method is not limited to this.

  The resin molding is various fibrous reinforcing materials widely used in industrial fields such as electric / electronics, machinery, automobiles, and building materials, and includes those in the form of films.

  The content of the cellulose fiber with respect to the matrix resin is 1% to 60% by volume, preferably 2% to 50%, more preferably 3% to 40%.

  Examples of the present invention are shown below, but the present invention is not limited to these Examples.

  First, the evaluation method of the cellulose fiber dispersion and the cellulose fiber-containing resin composite material according to the present invention will be described below.

(Dispersion evaluation method)
(1) Measurement of light transmittance As a test piece, using a molded body having a length of 1 cm, a width of 1 cm, and a thickness of 2 mm, the total transmitted light amount and scattered light with respect to the incident light amount of visible light are measured according to a spectrophotometer ASTM D-1003. It was measured. Evaluation was performed using the measurement result at 550 nm. The results in the examples are shown in Table 1 below.
(2) Evaluation of gelation After making a cellulose fiber dispersion, the state after standing still for one day and staying still was evaluated visually, and the gelled state was evaluated with and without gelation. Similarly, the results in Examples are shown in Table 1 below.
(3) Evaluation of fiber diameter and dispersion degree of cellulose fiber in composite material For each sample, the fiber diameter and dispersion degree of cellulose fiber having a fiber diameter of 2 nm or more and 200 nm or less were evaluated by the dispersion degree evaluation method. went.

(Composite material evaluation method)
(1) Tensile strength A test piece for measuring physical properties of a resin molded body was prepared and subjected to a tensile test using a tensile tester of Twin Column Model 3360 series manufactured by Instron. The length of the test piece was 5 cm, the width was 1 cm, the thickness was 2 mm, and the pulling speed was 1 cm per minute.
(2) Linear expansion coefficient About the molded object, temperature was changed within the range of 40-80 degreeC, and the linear expansion coefficient was measured. SII (Seiko Instruments) EXSTAR6000 TMA / SS6100 was used as a measuring device. The test piece was 1 cm in length, 1 cm in width, and 2 mm in thickness.

<Creation of cellulose fiber (dispersion)>
(Production Example 1 (Comparison))
Sulfuric acid bleached pulp obtained from conifers is added to 1.0% by mass in pure water, and cellulose fibers are defibrated using an Excel Auto Homogenizer manufactured by Nippon Seiki Seisakusho Co., Ltd. for 15 minutes at 3000 rpm. did. This aqueous dispersion was designated as cellulose fiber A. From the observation result of the scanning electron microscope, it was confirmed that the obtained cellulose fiber was fibrillated to an average fiber diameter of 250 nm and was microfibrillated.

(Production Example 2 (Comparison))
The cellulose fiber A aqueous dispersion prepared in Comparative Example 1 was treated at 15,000 rpm for 15 minutes with an Ultra Tarax manufactured by IKA. This aqueous dispersion was designated as cellulose fiber B. From the result of observation with a scanning electron microscope, the obtained cellulose fiber was kept at an average fiber diameter of 200 nm. The obtained sample was designated as cellulose fiber B.

(Production Example 3 (Comparative))
Cellulose fibers were defibrated by the same method as in Comparative Example 1 except that the concentration of the pulp in Comparative Example 1 was 5.0% by mass, but gelation occurred in 5 minutes. This aqueous dispersion was designated as cellulose fiber C. The average fiber diameter could not be measured because the dispersion was gelled.

(Production Example 4 (Comparison))
Cellulose fiber C aqueous dispersion prepared in Comparative Example 3 was processed at 15,000 revolutions for 15 minutes with IKA's Ultra Tarrax for 15 minutes as cellulose fiber D. The gel state could not be eliminated, and the average fiber diameter was not measured. It was possible.

(Production Examples 5-8)
Sulfuric acid bleached pulp obtained from conifers was added to acetone to the concentration shown in Table 1, and cellulose fibers were defibrated for 15 minutes at 1000 rpm with an Excel Auto Homogenizer manufactured by Nippon Seiki Seisakusho Co., Ltd. . This dispersion was designated as cellulose fiber E-1. Further, the cellulose fiber was defibrated at 3000 rpm for 15 minutes. This dispersion was designated as cellulose fibers E-2 to E-4. The obtained cellulose fiber diameter was described in Table 1 from the observation result of the scanning electron microscope.

(Production Examples 9-12)
Sulfuric acid bleached pulp obtained from conifers was added to acetone so as to have the concentration shown in Table 1, and cellulose fibers were defibrated for 15 minutes at 15,000 revolutions using IKA Ultra Turrax as a mechanical grinding method. This dispersion was designated as cellulose fibers F-1 to F-4. The obtained cellulose fiber diameter was described in Table 1 from the observation result of the scanning electron microscope.

(Production Examples 13 to 16)
Sulfuric acid bleached pulp obtained from conifers was added to acetone so as to have the concentration shown in Table 1. Ultra Apex Mill UAM-015 (manufactured by Kotobuki Kogyo Co., Ltd.) as a high shear mechanical grinding system, 0.5 mm Using the beads, the cellulose fibers were defibrated for 1 hour at a peripheral speed of 6 m / sec. This dispersion was designated as cellulose fibers G-1 to G-4. The obtained cellulose fiber diameter was described in Table 1 from the observation result of the scanning electron microscope.

(Production Examples 17-20)
Sulfuric acid bleached pulp obtained from conifers was added to acetone so as to have the concentration shown in Table 1, and high-pressure grinding system Artemizer HJP-2005 (manufactured by Sugino Machine Co., Ltd.) as a high shear mechanical grinding system, 200 MPa Was pulverized 180 times. This dispersion was designated as cellulose fibers H-1 to H-4. The obtained cellulose fiber diameter was described in Table 1 from the observation result of the scanning electron microscope.

(Production Examples 21 to 24)
Sulfuric acid bleached pulp obtained from conifers was added to ethanol to the concentration shown in Table 1, and cellulose fibers were defibrated for 15 minutes at 1000 rpm with an Excel Auto Homogenizer manufactured by Nippon Seiki Seisakusho Co., Ltd. . This dispersion was designated as cellulose fiber I-1. Further, the cellulose fibers were defibrated at 3000 rpm for 15 minutes. This dispersion was designated as cellulose fibers I-2 to I-4. The obtained cellulose fiber diameter was described in Table 1 from the observation result of the scanning electron microscope.

(Production Examples 25 to 28)
Sulfuric acid bleached pulp obtained from conifers was added to ethanol so as to have the concentration shown in Table 1, and mechanical pulverization method was used to defibrate cellulose fibers at 15,000 rpm for 15 minutes using Ultra Tarax manufactured by IKA. This dispersion was designated as cellulose fibers J-1 to J-4. The obtained cellulose fiber diameter was described in Table 1 from the observation result of the scanning electron microscope.

(Production Examples 29 to 32)
Sulfuric acid bleached pulp obtained from conifers was added to ethanol so as to have the concentration shown in Table 1. Ultra Apex Mill UAM-015 (manufactured by Kotobuki Kogyo Co., Ltd.) as a high shear mechanical grinding system, 0.5 mm Using the beads, the cellulose fibers were defibrated for 1 hour at a peripheral speed of 6 m / sec. This dispersion was designated as cellulose fibers K-1 to K-4. The obtained cellulose fiber diameter was described in Table 1 from the observation result of the scanning electron microscope.

(Production Examples 33 to 36)
Sulfuric acid bleached pulp obtained from conifers was added to ethanol so as to have the concentration shown in Table 1, and as a high shear mechanical pulverization system, high pressure pulverization system Artemizer HJP-2005 (manufactured by Sugino Machine Co., Ltd.), 200 MPa Was pulverized 180 times. This dispersion was designated as cellulose fibers L-1 to L-4. The obtained cellulose fiber diameter was described in Table 1 from the observation result of the scanning electron microscope.

(Production Examples 37 to 40)
Sulfuric acid bleached pulp obtained from conifers was added to methyl chloride so as to have the concentration shown in Table 1, and cellulose fibers were defibrated using an Excel auto homogenizer manufactured by Nippon Seiki Seisakusho Co., Ltd. for 15 minutes at 1000 rpm. did. This dispersion was designated as cellulose fiber M-1. Further, the cellulose fiber was defibrated at 3000 rpm for 15 minutes. This dispersion was designated as cellulose fibers M-2 to M-4. The obtained cellulose fiber diameter was described in Table 1 from the observation result of the scanning electron microscope.

(Production Examples 41 to 44)
Sulfuric acid bleached pulp obtained from conifers was added to methyl chloride so as to have the concentrations shown in Table 1, and cellulose fibers were defibrated for 15 minutes at 15,000 revolutions using Ultra Turrax manufactured by IKA as a mechanical grinding method. This dispersion was designated as cellulose fibers N-1 to N-4. The obtained cellulose fiber diameter was described in Table 1 from the observation result of the scanning electron microscope.

(Production Examples 45 to 48)
Sulfuric acid bleached pulp obtained from conifers was added to methyl chloride so as to have the concentration shown in Table 1, and Ultra Apex Mill UAM-015 (manufactured by Kotobuki Kogyo Co., Ltd.) as a high shear mechanical pulverization system. Cellulose fibers were defibrated using 5 mm beads for 1 hour at a peripheral speed of 6 m / sec. This dispersion was designated as cellulose fibers O-1 to O-4. The obtained cellulose fiber diameter was described in Table 1 from the observation result of the scanning electron microscope.

(Production Examples 49 to 52)
Sulfuric acid bleached pulp obtained from conifers was added to methyl chloride so as to have the concentration shown in Table 1, and as a high shear mechanical pulverization system, high pressure pulverization system Artemizer HJP-2005 (manufactured by Sugino Machine Co., Ltd.) The grinding process was performed 180 times at 200 MPa. This dispersion was designated as cellulose fibers P-1 to P-4. The obtained cellulose fiber diameters are shown in Table. It was described in 1.

  The sample prepared above was measured by the method for evaluating a dispersion. The results are shown in Tables 1 and 2.

  The cellulose fiber dispersion of the present invention is a dispersion having a high concentration without gelling in a dispersion with a high concentration even in a small fiber diameter, and a dispersion with a small dispersion (equal average fiber diameter). It turns out that it is a liquid.

<Creation of composite material>
100 g of each of the dispersions prepared in the comparative example and the production example are weighed, polyvinyl alcohol (PVA) is used for water, polyvinyl chloride (PVC) is used for acetone, and ethanol is used for ethanol. Polypropylene (PP) and 50 g of triacetyl cellulose (TAC) were dissolved in methyl chloride. This was transferred to a petri dish and dried in a drying box at 100 ° C. for 24 hours to prepare a composite material film. Further, after pulverizing the film in a mortar, using an injection molding machine (IS-80G type manufactured by Toshiba Machine Co., Ltd.), a test piece for measuring physical properties of each size, for example, 1 cm in length, 1 cm in width, and 2 mm in thickness is prepared. (Samples 1 to 56) were subjected to various measurements. Tables 3 and 4 show the cellulose fibers (dispersion) used for the prepared composite materials 1 to 56, the types of resins used, and the evaluation of the prepared composite materials.

  For composite materials using cellulose fiber dispersions in which cellulose fibers are pulverized in an organic solvent by a wet pulverization method to an average fiber diameter of 2 nm to 200 nm, the tensile strength is high, the linear expansion coefficient is low, and the transmittance It turns out that it is also favorable. That is, it was found that the mechanical strength of the base resin can be improved while maintaining the transparency, and the linear expansion can be reduced.

Claims (3)

Without adding water , cellulose fibers were pulverized to an average fiber diameter of 2 nm or more and 200 nm or less by an wet pulverization method in an organic solvent that is a solvent for dissolving and dispersing a matrix resin, and the cellulose fibers were uniformly dispersed in the organic solvent. Thereafter, the matrix resin is dissolved , cellulose fibers are dispersed in the organic solvent, and the matrix resin is dissolved, and then the organic solvent is removed. Production method. A method for producing a resin molded body, comprising producing a resin molded body using the cellulose fiber-containing resin composite material produced by the method for producing a cellulose fiber-containing resin composite material according to claim 1 . The method for producing a resin molded body according to claim 2 , wherein the resin molded body is formed in a film shape .