JP2020200386A - Resin composition and method for producing resin composition - Google Patents

Abstract

To provide a resin composition that has excellent environment properties by use of a biomass material, and prevents the impact strength from deteriorating and excels in high strength, high elastic modulus, and low thermal expansibility.SOLUTION: A resin composition containing a nano natural polymer is obtained by circulating polysaccharide slurry inside a polysaccharide slurry supply passage 3 through chambers 2a, 2b while circulating non-polysaccharide slurry in a second liquid medium supply passage 4 through chambers 2a, 2b.

Description

The present invention relates to a resin composition which is excellent in environmental properties due to the use of a biomass material, has little decrease in impact strength, and is excellent in high strength, high elastic modulus, and low thermal expansion.

Cellulose, which is the main component of the cell wall and fiber of plant cells, is one of the abundant renewable biomass resources on the earth. In recent years, research on cellulose nanofibers (hereinafter, also referred to as CNF) and cellulose nanocrystals, which are obtained by defibrating cellulose to nano size, has been actively conducted. It has been reported that cellulose nanofibers have excellent properties such as high strength, high elastic modulus, and low thermal expansion, and application development utilizing these characteristics is attracting attention.
In particular, compounding with a general-purpose plastic using NC as a filler improves the mechanical properties of the resin and thus makes it possible to reduce the weight, which is highly valuable from the viewpoint of utilization of renewable resources.

Patent Document 1 discloses microfibrous cellulose obtained by treating an aqueous suspension of cellulose pulp with a high-pressure homogenizer.

Further, Patent Document 2 discloses acetyl cellulose ultrafine fibers obtained by acetylating cellulose ultrafine fibers produced by bacteria. Cellulose ultrafine fibers produced by bacteria have a mass average degree of polymerization of 1700 or more, and are therefore excellent in terms of Young's modulus and tensile strength.

Japanese Unexamined Patent Publication No. 2000-17592 Japanese Unexamined Patent Publication No. 9-291102

However, in the method described in Patent Document 1, since a mechanical shearing force is applied to the fiber, the degree of polymerization is about 200, and as a result, sufficient strength cannot be obtained.
Further, since the cellulose fiber produced by the bacteria described in Patent Document 2 has a large amount of Iα-type crystal components, there is still room for improvement in terms of the reinforcing effect.

In view of the above problems in the prior art, the present invention provides a resin composition having excellent environmental properties, little decrease in impact strength, high strength, high elastic modulus, and low thermal expansion by using a biomass material. The purpose is.

As a result of diligent research, the present inventors have found that the above-mentioned problems can be solved by blending cellulose nanofibers having a specific degree of polymerization as a biomass material into a resin.

That is, the resin composition of the present invention is characterized by containing a nano-natural polymer.

It is a conceptual diagram of the manufacturing (defibration processing) apparatus of CNF. It is a conceptual diagram of the manufacturing (defibration processing) apparatus of another CNF. FIG. 2 is a conceptual diagram showing an enlarged part of a CNF manufacturing (defibration treatment) apparatus in FIG. 2.

Next, the resin composition of one embodiment of the present invention will be described, but the present invention is not limited to this embodiment.

The nanonatural polymer used in the present invention is a fibrous substance having a diameter of less than 1 to 1000 nm and having a length of 100 times or more the diameter, or a natural polymer nanofiber having a diameter of 10 to 50 nm and a length of 10 to 50 nm. It is a natural polymer nanocrystal which is a rod-shaped or spindle-shaped ultrafine crystal having a diameter of 100 to 500 nm or less.

The natural polymer used in the present invention is not particularly limited, and examples thereof include polysaccharides such as cellulose, chitin and chitosan, proteins such as collagen and gelatin, polylactic acid and polycaprolactam.

Next, a method for preparing cellulose nanofibers and an aqueous solution of cellulose nanocrystals using cellulose as a natural polymer will be described. In the present invention, examples of CNF include CNFs derived from polysaccharides including natural plants such as wood fibers, hardwoods, conifers, bamboo fibers, sugar cane fibers, seed hair fibers, and leaf fibers, and these CNFs are used alone. Alternatively, two or more types may be mixed and used. Further, as the polysaccharide, it is preferable to use pulp having an α-cellulose content of 60% to 99% by mass. If the purity has an α-cellulose content of 60% by mass or more, the fiber diameter and fiber length can be easily adjusted and entanglement between fibers can be suppressed, and an α-cellulose content of less than 60% by mass was used. Compared with the case, the thermal stability at the time of melting is high, the impact strength is not lowered, the coloring suppressing effect is good, and the effect of the present invention can be further improved. On the other hand, when 99% by mass or more is used, it becomes difficult to defibrate the fibers at the nano level.

The CNF in the present invention can be obtained as a CNF dispersion (hereinafter, may be referred to as a water-containing CNF) by performing the following defibration treatment.
The defibration treatment is performed by using the underwater facing collision method (hereinafter, also referred to as ACC method) shown in FIG. This is a method in which pulp suspended in water is introduced into two opposing nozzles (FIGS. 1: 108a and 108b) in a chamber (FIG. 1: 107), and the pulp is injected and collided from these nozzles toward one point. is there. The device shown in FIG. 1 is of a liquid circulation type, with a tank (FIG. 1: 109), a plunger (FIG. 1: 110), two opposing nozzles (FIGS. 1: 108a, 108b), and heat as needed. A exchanger (FIG. 1: 111) is provided, and fine particles dispersed in water are introduced into two nozzles and injected from the nozzles (FIGS. 1: 108a and 108b) facing each other under high pressure to cause a facing collision in water.

Before performing the defibration treatment, the defibration treatment may be carried out using a pretreatment device (FIGS. 2 and 3). Further, as another defibration method, such a pretreatment device may be used. The defibration treatment using the pretreatment apparatus is carried out by colliding high-pressure water of about 50 to 400 MPa with the polysaccharide prepared in a water mixture of 0.5 to 10% by mass. This can be done, for example, by using the manufacturing apparatus 1 shown in FIG. The manufacturing apparatus 1 has a polysaccharide slurry supply path 3 which is a first liquid medium supply path arranged so that the polysaccharide slurry can be supplied to one chamber 2, and a non-polysaccharide slurry which is water, for example, in one chamber. It comprises a second liquid medium supply path 4 that circulates through 2. The one chamber 2 is provided with an orifice injection unit 5 that injects the non-polysaccharide slurry of the second liquid medium supply path 4 in a direction intersecting the polysaccharide slurry supply direction from the polysaccharide slurry supply path 3. The polysaccharide slurry supply path 3 allows the polysaccharide slurry to be circulated through one chamber 2.

The polysaccharide slurry supply path 3 and the second liquid medium supply path 4 have a mutual intersection 6 in one chamber 2.
The polysaccharide slurry supply path 3 is a polysaccharide slurry supply section, and the tank 7 and the pump 8 for storing the polysaccharide slurry are arranged in the circulation path 9, while the second liquid medium supply path 4 is the tank 10, the pump 11, and the heat. The exchanger 12 and the plunger 13 are arranged in the liquid medium supply path 4 which is a circulation path.

The non-polysaccharide slurry is, for example, water, which is initially stored in the tank 10, and then passes through the intersection 6 with the operation of the cellulose nanofiber manufacturing apparatus 1, and the nano-miniaturized polysaccharide stored in the tank 10 is used. Those in a state where they are to be contained at a concentration according to the degree of operation are also comprehensively referred to.

As shown in FIG. 3, the circulation path 9 of the polysaccharide slurry supply path 3 is arranged in a manner of penetrating the chamber 2, and the non-polysaccharide slurry can be orifice-injected in the direction intersecting the circulation path 9 so as to penetrate the circulation path 9. The orifice injection port 14 of the orifice injection section 5 connected to the plunger 13 of the second liquid medium supply path 4 opens inside the chamber 2. The discharge port 15 of the chamber 2 is provided at a position facing the orifice injection port 14 of the chamber 2, and the circulation path of the second liquid medium supply path 4 is connected to the discharge port 15 of the chamber 2 to form a second liquid. The medium supply path 4 is configured.

On the other hand, the circulation path 9 of the polysaccharide slurry supply path 3 is formed by using, for example, a vinyl hose, a rubber hose, an aluminum pipe, or the like, and the valve is opened only in the chamber 2 direction on the entry side of the circulation path 9 into the chamber 2. The directional valve 16 is attached. Further, a one-way valve 17 that is opened only in the discharge direction from the chamber 2 is attached to the exit side of the circulation path 9 from the chamber 2. In addition, an air suction valve 18 is attached to the circulation path 9 between the chamber 2 and the one-way valve 17, and the air suction valve 18 is opened only in the direction of sucking air into the circulation path 9 from the outside.

According to the above-mentioned cellulose nanofiber manufacturing apparatus, cellulose nanofibers are manufactured as follows.
The non-polysaccharide slurry is circulated through the chamber 2 through the second liquid medium supply path 4. Specifically, the pump 11 is used to pass the non-polysaccharide slurry in the tank 10 through the heat exchanger 12 and the plunger 13 to circulate in the liquid medium supply path 4. On the other hand, the polysaccharide slurry is circulated in the polysaccharide slurry supply path 3 via the chamber 2. Specifically, the pump 8 is used to circulate the polysaccharide slurry in the tank 7 in the circulation path 9 formed by using a vinyl hose, a rubber hose, or the like.

As a result, the non-polysaccharide slurry circulating in the second liquid medium supply path 4 is orifice-injected to the polysaccharide slurry circulating in the polysaccharide slurry supply path 3 and flowing in the chamber 2. Specifically, high-pressure water is supplied from the plunger 13 to the orifice injection port 14 connected to the plunger 13, and the orifice is injected from the orifice injection port 14 toward the circulation path 9 at a high pressure of about 50 to 400 MPa.

As a result, it passes through the through holes 26a and 26 formed in advance in the circulation path 9 formed by using, for example, a vinyl hose, a rubber hose, an aluminum pipe, etc., and passes through the inside of the circulation path 9 in a direction intersecting the circulation path 9. The non-polysaccharide slurry is discharged toward the discharge port 15 of the chamber 2 while involving the polysaccharide slurry circulating in the circulation path 9, and flows into the second liquid medium supply path 4. As a result, the non-polysaccharide slurry circulates in the second liquid medium supply path 4 again.
In the process of repeating the above process, the polysaccharides in the polysaccharide slurry circulating in the polysaccharide slurry supply path 3 and circulating in the chamber 2 and the polysaccharides in the non-polysaccharide slurry circulating in the second liquid medium supply path 4 are gradually defibrated. Therefore, a CNF dispersion having a high degree of uniformity of defibration according to the application can be obtained.

The CNF obtained as described above has a structural formula represented by the following chemical formula 1 without any structural change of the cellulose molecule because the nanominiaturization is performed by cleaving only the interaction between the natural cellulose fibers. In other words, the CNF used in the present invention means that it has 6 hydroxyl groups in the cellobiose unit in Chemical Formula 1 and is not chemically modified. This can be confirmed by comparing the IR spectrum of cellulose with the CNF used in the present invention using FT-IR. By this ACC method, the average particle length of cellulose fibers can be pulverized to 10 μm, and as a result, CNF having an average thickness of 3 to 200 nm and an average length of 0.1 μm or more can be obtained.

The cellulose nanocrystal in the present invention is obtained by subjecting the cellulose fiber obtained by the ACC method to a chemical treatment such as acid hydrolysis using an acid such as sulfuric acid, or to the pulp before the micronization treatment by the ACC method. , Sulfur, etc., and then subjected to chemical treatment such as acid hydrolysis, and then micronized by the ACC method. Cellulose nanocrystals are also called cellulose nanowhiskers.

For the measurement of the average thickness and the average fiber length, a scanning electron microscope (SEM), a transmission electron microscope (TEM), etc. are appropriately selected, CNF is observed and measured, and 20 or more are selected from the obtained photographs. , Obtained by averaging each of these. On the other hand, in the counter-collision treatment, the applied energy is far less than the energy for breaking the covalent bond (estimated to be 1/300 or less), and the degree of polymerization of cellulose does not decrease. The cellulose nanofibers obtained by this ACC method show amphipathic properties in which hydrophilic sites and hydrophobic sites coexist.

In the present invention, TEMPO oxidation catalyst, phosphoric acid treatment, ozone treatment, enzyme treatment, maleic acid treatment, hydrophobic modification with alkenyl succinic anhydride, and hydrophobicity with alkyl keten dimer, which are known as other methods for producing cellulose nanofibers. Cellulose-based fibers obtained by chemical treatment such as modification and hydrophobic modification by acetylation, or by wet grinding using mechanical action such as grinder (stone mill type grinder), disc type refiner, conical refiner, etc. Even cellulose nanofibers obtained by a physical method of thinning can be used as a CNF dispersion in the present invention.

In the present invention, it is preferable to use a nano-natural polymer having an average degree of polymerization in the range of 450 to 900. This is because those having a degree of polymerization higher than the average degree of polymerization of 900 are inferior in their ability to support the resin due to a decrease in the specific surface area of the nanonatural polymer, and the reinforcing effect of the resin is inferior. If the average degree of polymerization is less than 450, the number of steps required for defibration increases, which increases the cost of producing nanonatural polymers. Therefore, the average degree of polymerization of the nanonatural polymer used is preferably in the range of 450 to 900, more preferably 540 to 850, and the average degree of polymerization is 730 to 850. More preferred. Further, the average degree of polymerization is most preferably 750 to 845.

(B) Resin component Examples of the (B) resin component used in the composition of the present invention include (B-1) thermoplastic resin, (B-2) curable resin, and (B-3) rubber.

(B-1) Thermoplastic resin:
Here, the thermoplastic resin refers to a resin that is melt-molded by heating. Specific examples thereof include general-purpose plastics such as polyethylene (HDPE, MDPE, LDPE), polyvinyl chloride, polypropylene, polystyrene, ABS resin, AS resin (copolymer of polystyrene and acrylic nitrile), methacrylic resin, polyamide, polyacetal, and the like. General-purpose engineering plastics such as polycarbonate, modified polyphenylene ether, polyethylene terephthalate, polyethylene for ultrapolymers, or polysulfone, polyether sulfone, polyphenylene sulfide, polyarylate, polyamideimide, polyetherimide, polyetherketone, polyimide, liquid crystal polymer, At least one selected from each group of super engineering plastics such as fluororesin can be mentioned. Resins such as PVA and polyethylene glycol that can be used as liquids that are soluble in water or liquid at room temperature can also be used. In addition, these thermoplastic resins can be used individually by 1 type or in combination of 2 or more types.

(B-2) Curable Resin When (B-2) Curable Resin is used as the (B) Matrix component in the resin composition of the present invention, the curable resin is used in the resin composition of the present invention. It exists in a state of being uniformly dispersed with cellulose nanofibers. There is no particular limitation on the type of curable resin. Examples of the thermosetting resin include epoxy resin, phenol resin, urea resin, melamine resin, polyurethane, unsaturated polyester resin, silicon resin, polyimide resin, diriaphthalate resin and the like. Resins such as dicyclopentadiene resin that can be used as a liquid having the characteristics of being soluble in water and liquid at room temperature can also be used. Further, for example, a resin that is cured by something other than heat, such as a photocurable resin or a moisture-curable resin, can also be used. In addition, these curable resins can be used individually by 1 type or in combination of 2 or more types.

(B-3) Rubber Examples of the rubber used include natural rubber, chloroprene rubber, ethylene-propylene-non-conjugated diene copolymer rubber, ethylene-butene-1 copolymer rubber, ethylene-hexene copolymer rubber, and ethylene-octene. Polymerized rubber, polybutadiene, styrene-butadiene block copolymer rubber, styrene-butadiene copolymer rubber, partially hydrogenated styrene-butadiene-styrene block copolymer rubber, styrene-isoprene block copolymer rubber, partially hydrogenated styrene-isoprene block copolymer Rubber, polyurethane rubber, styrene graft-ethylene-propylene-non-conjugated diene copolymer rubber, styrene-graft-ethylene-propylene copolymer rubber, styrene / acrylonitrile-graft-ethylene-propylene-non-conjugated diene copolymer rubber, styrene / acrylonitrile -Graft-ethylene-propylene copolymer rubber, chlorosulfonated polyethylene rubber, silicon rubber, ethylene-vinyl acetate rubber, epichlorohydrin rubber, polysulfide rubber and the like.
Further, a polymer alloy obtained by blending these rubbers with the resins (B-1) and (B-2) described above may be used. Rubber that can be used in liquids such as latex rubber can also be used. The content of rubber in the polymer alloy is preferably 50% by mass or less from the viewpoint of adding new properties to the properties of the resin.

[Resin composition]
Examples of the method for producing the resin composition of the present invention include a method of melt-kneading each component by a conventionally known method.
For example, each component is subjected to shearing force using a tumble mixer, a Henschel mixer, a ribbon blender, a high-speed mixer represented by a super mixer to remove water and dispersed and mixed, and then an extruder, a Banbury mixer, a roll, etc. The method of melt-kneading is appropriately selected.

The molding method using the resin composition of the present invention is not particularly limited, and molding methods such as injection molding, injection compression molding, extrusion molding, and hollow molded body can be applied.
Since the molded product using the polyolefin resin composition of the present invention has the above-mentioned properties, it can be suitably used in, for example, OA equipment, information / communication equipment, automobile parts, building materials, and the like.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The average degree of polymerization described in Examples and Comparative Examples was measured by the following measuring method.

(Measurement of degree of polymerization of CNF)
CNF sample solid content 0.15 g is dissolved in 30 ml of 0.5 M copper ethylenediamine solution, kept warm at 25 ° C using a Canon Fenceke kinematic viscosity tube, and then the viscosity is measured by measuring the flow time. Was done. The degree of polymerization was calculated by the following formula, where the viscosity of this CNF copper ethylenediamine solution was η and the viscosity of the 0.5 M copper ethylenediamine solution was η0. The average degree of polymerization is the average value of the values measured three times.
Extreme viscosity [η] = (η / η0) / {c (1 + A × η / η0)} (where c is the fibrous cellulose concentration (g / dL) at the time of viscosity measurement, and A is a unique value depending on the type of solution. In the case of 0.5M copper ethylenediamine solution, A = 0.28)
Degree of polymerization DP = [η] / aK (K and a are values determined by the type of polymer and solvent used. In the case of cellulose dissolved in copper ethylenediamine, K = 5.7 × 10-3, a = 1 )

(Example 1)
Cellulose nanofibers were prepared from coniferous bleached pulp by the underwater opposed collision method (ACC) (hereinafter referred to as NB). Next, the degree of polymerization and crystallinity of CNF were measured.
Next, medium-density polyethylene (3621MRM manufactured by Luporen) was used as the resin, and the ratio of NB to the resin was set to 1: 9 to obtain a composite resin.
A twin-screw extruder Labplast Mill manufactured by Toyo Seiki Co., Ltd. was used for compounding. The screw diameter was φ25 mm L / D: 30. In order to obtain a test piece for physical property evaluation, a dumbbell test piece 1BA and a strip-shaped test piece were prepared using a small injection molding machine NPX7-1F manufactured by Nissei Resin Industry Co., Ltd.

(Example 2)
Bleached pulp derived from hardwood was prepared with cellulose nanofibers by the underwater opposed collision method (ACC) (hereinafter referred to as LB). Next, the degree of polymerization and crystallinity of CNF were measured.
Next, medium-density polyethylene (3621MRM manufactured by Luporen) was used as the resin, and the ratio of LB to the resin was set to 1: 9 to obtain a composite resin.
A twin-screw extruder Labplast Mill manufactured by Toyo Seiki Co., Ltd. was used for compounding. The screw diameter was φ25 mm L / D: 30. In order to obtain a test piece for physical property evaluation, a dumbbell test piece 1BA and a strip-shaped test piece were prepared using a small injection molding machine NPX7-1F manufactured by Nissei Resin Industry Co., Ltd.

(Example 3)
Bamboo-derived bleached pulp was prepared with cellulose nanofibers by the underwater opposed collision method (ACC) (hereinafter referred to as BB). Next, the degree of polymerization and crystallinity of CNF were measured.
Next, medium-density polyethylene (3621MRM manufactured by Luporen) was used as the resin, and the ratio of BB to the resin was set to 1: 9 to obtain a composite resin.
A twin-screw extruder Labplast Mill manufactured by Toyo Seiki Co., Ltd. was used for compounding. The screw diameter was φ25 mm L / D: 30. In order to obtain a test piece for physical property evaluation, a dumbbell test piece 1BA and a strip-shaped test piece were prepared using a small injection molding machine NPX7-1F manufactured by Nissei Resin Industry Co., Ltd.

(Example 4)
Cellulose nanofibers were prepared from coniferous bleached pulp by the underwater opposed collision method (ACC) (hereinafter referred to as NB). Next, the degree of polymerization and crystallinity of CNF were measured.
Next, medium-density polyethylene (3621MRM manufactured by Luporen) was used as the resin, and the ratio of NB to the resin was 5:95 to obtain a composite resin.
A twin-screw extruder Labplast Mill manufactured by Toyo Seiki Co., Ltd. was used for compounding. The screw diameter was φ25 mm L / D: 30. In order to obtain a test piece for physical property evaluation, a dumbbell test piece 1BA and a strip-shaped test piece were prepared using a small injection molding machine NPX7-1F manufactured by Nissei Resin Industry Co., Ltd.

(Example 5)
Bleached pulp derived from hardwood was prepared with cellulose nanofibers by the underwater opposed collision method (ACC) (hereinafter referred to as LB). Next, the degree of polymerization and crystallinity of CNF were measured.
Next, medium-density polyethylene (3621MRM manufactured by Luporen) was used as the resin, and the ratio of LB to the resin was set to 5:95 to obtain a composite resin.
A twin-screw extruder Labplast Mill manufactured by Toyo Seiki Co., Ltd. was used for compounding. The screw diameter was φ25 mm L / D: 30. In order to obtain a test piece for physical property evaluation, a dumbbell test piece 1BA and a strip-shaped test piece were prepared using a small injection molding machine NPX7-1F manufactured by Nissei Resin Industry Co., Ltd.

(Example 6)
Bamboo-derived bleached pulp was prepared with cellulose nanofibers by the underwater opposed collision method (ACC) (hereinafter referred to as BB). Next, the degree of polymerization and crystallinity of CNF were measured.
Next, medium-density polyethylene (3621MRM manufactured by Luporen) was used as the resin, and the ratio of BB to the resin was set to 5:95 to obtain a composite resin.
A twin-screw extruder Labplast Mill manufactured by Toyo Seiki Co., Ltd. was used for compounding. The screw diameter was φ25 mm L / D: 30. In order to obtain a test piece for physical property evaluation, a dumbbell test piece 1BA and a strip-shaped test piece were prepared using a small injection molding machine NPX7-1F manufactured by Nissei Resin Industry Co., Ltd.

(Example 7)
Cellulose nanofibers were prepared from coniferous bleached pulp by the underwater opposed collision method (ACC) (hereinafter referred to as NB). Next, the degree of polymerization and crystallinity of CNF were measured.
Next, medium-density polyethylene (3621MRM manufactured by Luporen) was used as the resin, and the ratio of NB to the resin was 3:97 to obtain a composite resin.
A twin-screw extruder Labplast Mill manufactured by Toyo Seiki Co., Ltd. was used for compounding. The screw diameter was φ25 mm L / D: 30. In order to obtain a test piece for physical property evaluation, a dumbbell test piece 1BA and a strip-shaped test piece were prepared using a small injection molding machine NPX7-1F manufactured by Nissei Resin Industry Co., Ltd.

(Example 8)
Bleached pulp derived from hardwood was prepared with cellulose nanofibers by the underwater opposed collision method (ACC) (hereinafter referred to as LB). Next, the degree of polymerization and crystallinity of CNF were measured.
Next, medium-density polyethylene (3621MRM manufactured by Luporen) was used as the resin, and the ratio of LB to the resin was 3:97 to obtain a composite resin.
A twin-screw extruder Labplast Mill manufactured by Toyo Seiki Co., Ltd. was used for compounding. The screw diameter was φ25 mm L / D: 30. In order to obtain a test piece for physical property evaluation, a dumbbell test piece 1BA and a strip-shaped test piece were prepared using a small injection molding machine NPX7-1F manufactured by Nissei Resin Industry Co., Ltd.

(Example 9)
Bamboo-derived bleached pulp was prepared with cellulose nanofibers by the underwater opposed collision method (ACC) (hereinafter referred to as BB). Next, the degree of polymerization and crystallinity of CNF were measured.
Next, medium-density polyethylene (3621MRM manufactured by Luporen) was used as the resin, and the ratio of BB to the resin was 3:97 to obtain a composite resin.
A twin-screw extruder Labplast Mill manufactured by Toyo Seiki Co., Ltd. was used for compounding. The screw diameter was φ25 mm L / D: 30. In order to obtain a test piece for physical property evaluation, a dumbbell test piece 1BA and a strip-shaped test piece were prepared using a small injection molding machine NPX7-1F manufactured by Nissei Resin Industry Co., Ltd.

(Comparative Example 1)
A test piece was prepared in the same manner as in Examples 1 to 9 in order to evaluate the physical properties of medium-density polyethylene (3621MRM manufactured by Luporen).

(Measurement of physical property values)
The crystallinity of the cellulose nanofibers was evaluated by an X-ray diffractometer Smart Lab 9Kw manufactured by Rigaku Co., Ltd. For the measurement of mechanical properties, a three-point bending test and a tensile test were performed. In each case, Ez-LX manufactured by Shimadzu Corporation was used, and the three-point bending test speed was 2.0 mm / min and the tensile test speed was 10.0 mm / min.

(Impact test)
An impact test was performed using a digital impact tester (DG-VB2, Toyo Seiki Seisakusho Co., Ltd., hammer capacity: 4.0 J) in accordance with JIS K7111-1: 2012.

Measurements of the raw materials of cellulose nanofibers, the degree of polymerization and the degree of crystallization, the flexural modulus of the composite resin, the flexural modulus, the tensile modulus, the tensile strength, the tensile strain, and the impact test for Examples 1 to 9 and Comparative Example 1. The results are shown in Table 1.

Claims (4)

A resin composition characterized by containing a nano-natural polymer. The resin composition according to claim 1, wherein the nanonatural polymer is a cellulose nanofiber. The resin composition according to claim 2, wherein the cellulose nanofibers have an average degree of polymerization of 450 to 900. A method for producing a resin composition, which comprises a step of heating a nanonatural polymer and a resin and applying a shearing force to remove water and mixing them.

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