Biodegradable resin composition and biomass nanofiber particles

Abstract

To provide a biodegradable resin composition which can improve impact resistance while satisfactorily keeping tensile strength with respect to a conventional biodegradable resin.SOLUTION: A biodegradable resin composition contains a biomass nanofiber and a biodegradable resin, wherein a content of the biomass nanofiber is 0.1 to 10 mass%.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a biodegradable resin composition and biomass nanofiber particles for the biodegradable resin composition. [Background technology]

[0002] Biodegradable plastics are expected to solve waste disposal problems because they are ultimately broken down into water and carbon dioxide by the action of microorganisms. However, because biodegradable plastics are based on the premise of being biodegraded, they tend to have low strength when molded into articles.

[0003] In recent years, the rising price of petroleum, the risk of its depletion, and the problem of global warming due to increased carbon dioxide emissions have attracted attention, and interest in new materials derived from biomass has been growing in order to solve these problems. One such new material is cellulose nanofiber, and development of its manufacturing method and various applications has been progressing.

[0004] Therefore, in order to increase the strength of biodegradable plastics without impairing their biodegradability, Patent Document 1 proposes a biodegradable composite material in which cellulose nanofibers are blended with a biodegradable resin to enhance the strength and biodegradability. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-21041 Summary of the Invention [Problem to be solved by the invention]

[0006] However, although Patent Document 1 evaluates various strengths and biodegradability, it does not consider impact resistance at all. In the examples of Patent Document 1, various strengths are improved when the cellulose nanofiber is 20 mass% or more, but in this case, there is a concern that the impact resistance may be inferior.

[0007] In view of the above, an object of the present invention is to provide a biodegradable resin composition which is capable of maintaining good tensile strength and improving impact resistance compared to conventional biodegradable resins. [Means for solving the problem]

[0008] As a result of intensive research aimed at solving the above problems, the present inventors have come up with the following invention and found that the above problems can be solved.

[0009] [1] A biodegradable resin composition comprising a biomass nanofiber and a biodegradable resin, the content of the biomass nanofiber being 0.1 to 10 mass%. [2] The biodegradable resin composition according to [1], wherein the content of the biomass nanofibers is 0.8 to 8 mass %. [3] The biodegradable resin composition according to [1] or [2], wherein the biomass nanofibers are mechanically defibrated biomass nanofibers. [4] The biodegradable resin composition according to any one of [1] to [3], wherein the biomass nanofibers have a degree of polymerization of 150 to 900. [5] A biomass nanofiber particle for a biodegradable resin composition according to any one of [1] to [4], which is made of a biomass nanofiber, and which is formed by agglomeration of a plurality of biomass nanofibers each having an average fiber diameter of 5 to 50 nm, the biomass nanofiber having a degree of polymerization of 150 to 900, a moisture content of 9 mass% or less, and a median diameter of 3 to 15 μm. [6] Biomass nanofiber particles according to [5], having a content of functional groups selected from at least one of a carboxy group, a carboxymethyl group, a phosphate group, a sulfate group, a phosphite group, a xanthene group, and a sulfo group of 0.1 mmol / g or less. Effect of the Invention

[0010] According to the present invention, it is possible to provide a biodegradable resin composition which can maintain good tensile strength and improve impact resistance compared to conventional biodegradable resins. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the biodegradable resin composition and biomass nanofiber particles according to one embodiment (the present embodiment) of the present invention will be described.

[0012] [Biodegradable resin composition] The biodegradable resin composition according to the present embodiment contains biomass nanofibers and a biodegradable resin, and the content of the biomass nanofibers is 0.1 to 10 mass %. If the content of the biomass nanofibers is less than 0.1, it is not possible to maintain good tensile strength and improve impact resistance compared to conventional biodegradable resins.

[0013] From the viewpoint of maintaining good tensile strength and more reliably improving impact resistance, the content of biomass nanofibers is preferably 0.8 to 8 mass %, and more preferably 1 to 7 mass %.

[0014] (Biomass nanofiber) The biomass nanofiber (BNF) according to the present embodiment is a nanofiber made of a biological polymer that is poorly soluble in water, and examples of such nanofibers include cellulose nanofiber, chitin nanofiber, chitosan nanofiber, silk nanofiber, etc. Among these, cellulose nanofiber (CNF) is preferred from the viewpoints of chemical stability, thermal stability, and cost. The average fiber diameter of the biomass nanofibers is preferably 5 to 100 nm, more preferably 6 to 50 nm, even more preferably 7 to 40 nm, and even more preferably 8 to 25 nm, and of these, preferably 8 to 15 nm. The average length of the biomass nanofibers is preferably 0.5 to 100 μm, and more preferably 10 to 100 μm. The average fiber diameter and average length of biomass nanofibers can be calculated from the fiber diameter and length (approximately n = 20) measured based on electron microscope photographs taken at an appropriate magnification.

[0015] Biomass nanofibers are produced by various production methods, but mechanically defibrated biomass nanofibers produced by mechanical defibration are preferred. Mechanically defibrated biomass nanofibers are obtained by cutting raw biomass to a predetermined length using a beater or refiner, and fibrillating or pulverizing (mechanically pulverizing) it using a high-pressure homogenizer, grinder, impact crusher, bead mill, etc.

[0016] On the other hand, chemically modified biomass nanofibers are obtained by making the raw biomass easier to pulverize by chemical treatment, and then pulverizing it by mechanical defibration. Therefore, chemically modified biomass nanofibers are chemically modified. For example, when chemically modified CNF such as TEMPO oxidized CNF is used, metal ions contained in the salt may act as impurities. Metal ions are, for example, sodium, aluminum, copper, and silver. However, mechanically defibrated biomass nanofibers are not chemically modified during pulverization, and only an aqueous medium is used as a medium, so there are no compounds that are likely to affect the resin properties, and they are chemically and thermally stable. In addition, even if treated with a high-pressure homogenizer, mechanically defibrated biomass nanofibers are less likely to experience a decrease in the degree of polymerization.

[0017] Here, the mechanically defibrated biomass nanofibers have a content of any one of sodium, aluminum, copper, and silver (preferably, any two of each, and more preferably, any three of each) of 0.1 mass% or less, and preferably 0.01 mass% or less. Furthermore, the content can be determined by measurement using high-frequency inductively coupled plasma optical emission spectroscopy, EPMA using an electron probe microanalyzer, or elemental analysis using X-ray fluorescence spectroscopy, and it is preferable that the content in at least one of the above methods is 0.1 mass% or less, and more preferably 0.01 mass% or less.

[0018] Mechanically defibrated biomass nanofibers are produced using only the force of a water jet, resulting in less contamination with impurities compared to chemical modification. Also, compared to chemical modification, there is less loss in the degree of polymerization and crystallinity from the original raw material. Furthermore, compared to chemical modification, there is an advantage in that fewer steps are required, such as no cleaning process being required after chemical modification.

[0019] When the mechanically defibrated biomass nanofibers are cellulose nanofibers (mechanically defibrated cellulose nanofibers), the degree of polymerization is preferably 150 to 900, and more preferably 400 to 900. When the degree of polymerization is 150 or more, impact resistance can be improved more reliably. When the degree of polymerization is 900 or less, the dispersibility of the mechanically defibrated biomass nanofibers, including the cellulose nanofibers, in resin can be improved.

[0020] The degree of polymerization is the number of glucose units linked together, which are the minimum structural units of cellulose, and is determined by a viscosity method using a copper ethylenediamine solution.

[0021] (biodegradable resin) As the biodegradable resin, a conventionally known resin can be used. For example, polyhydroxyalkanoates such as polyglycolic acid (PGA), polylactic acid (PLA), polyhydroxybutyrate (PHB), and poly(hydroxybutyrate / hydroxyhexanoate) (PHBH); polycaprolactone (PCL), polybutylene succinate (PBS), poly(caprolactone / butylene succinate) (PCLBS), poly(butylene succinate / adipate) (PBSA), and poly(butylene succinate / carboxamide) (PCLBS) can be used. Examples of suitable polylactic acid resins include polyester resins such as poly(ethylene terephthalate / succinate) (PEC), poly(ethylene terephthalate / succinate) (PETS), poly(butylene adipate / terephthalate) (PTMAT), polyethylene succinate (PES), and poly(ethylene succinate / adipate); (polylactic acid / polybutylene succinate-based) block copolymers; polyvinyl alcohol (PVA); modified starch; cellulose acetate; chitin; chitosan; lignin, etc. Among these, polylactic acid (PLA) is preferred.

[0022] From the viewpoint of obtaining practical rigidity, the weight average molecular weight of the biodegradable resin is preferably 5,000 or more, more preferably 50,000 or more, and even more preferably 100,000 or more. The weight average molecular weight is an average molecular weight calculated in terms of polystyrene measured by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent.

[0023] The resin composition of this embodiment can be produced by mixing the biomass nanofibers described above (preferably the biomass nanofiber particles described below) and a biodegradable resin in a blender or the like, drying in a constant temperature bath at about 80°C, and then melt-kneading in a twin-screw kneader. During the above mixing or into the biodegradable resin, sodium oxalate, calcium oxalate, sodium benzoate, calcium benzoate, calcium phthalate, calcium tartrate, magnesium stearate, higher fatty acids, higher fatty acid metal salts, higher fatty acid esters, higher fatty acid amides, and the like, which have the effect of crystallization accelerators, as well as rubber components, plasticizers, ultraviolet protection agents, heat stabilizers, light stabilizers, anti-fog agents, antistatic agents, flame retardants, antioxidants, pigments, colorants, and the like, may be added within a range that does not impair the resin properties.

[0024] Furthermore, from the viewpoint of maintaining good tensile strength and more reliably improving impact resistance, the biodegradable resin composition according to this embodiment preferably contains 0.1 to 12 parts by mass of biomass nanofibers per 100 parts by mass of biodegradable resin, more preferably 0.3 to 10 parts by mass, and even more preferably 0.7 to 8 parts by mass.

[0025] The resin composition of the present embodiment may be in the form of, for example, a pellet, a sheet, a fiber, a plate, a rod, etc., but the pellet form is more preferred from the viewpoint of ease of post-processing and ease of transportation. Preferred pellet shapes in this case include a round shape, an elliptical shape, a cylindrical shape, etc., which differ depending on the cutting method used during extrusion processing.

[0026] The resin composition of the present embodiment can be used as various resin molded products. There is no particular limitation on the method for producing the resin molded product, and various known production methods can be used, including injection molding, extrusion molding, blow molding, inflation molding, and foam molding.

[0027] The resin composition of the present embodiment has excellent mechanical properties (tensile elasticity) and impact resistance, and can therefore be suitably used in a variety of parts and products.

[0028] [Biomass nanofiber particles] The biomass nanofiber particles according to this embodiment are the biomass nanofiber particles for the biodegradable resin composition of the present invention described above, and are made of biomass nanofibers. The biomass nanofibers are the biomass nanofibers already described, and are preferably mechanically defibrated biomass nanofibers, and specifically, the following biomass nanofiber particles are preferred.

[0029] The biomass nanofiber particles of this embodiment are in the form of a particulate aggregate of multiple biomass nanofibers with an average fiber diameter of 5 to 50 nm, and the biomass nanofibers have a degree of polymerization of 150 to 900, a moisture content of 9 mass% or less, and a median diameter of 3 to 15 μm.

[0030] Since the biomass nanofibers are in the form of particulate aggregates of multiple biomass nanofibers with an average fiber diameter of 5 to 50 nm, the aggregates of biomass nanofibers break down in the resin when melted and kneaded into the resin, allowing the biomass nanofibers to be highly dispersed in the resin.

[0031] When the degree of polymerization of the biomass nanofiber is 150 to 900, it is possible to more reliably improve the impact resistance and improve the dispersibility in the resin. The degree of polymerization is more preferably 400 to 900, and more preferably 600 to 850.

[0032] When the biomass nanofiber particles have a low moisture content of 9% by mass or less, hydrolysis is less likely to occur even when the biomass nanofiber particles are added to a biodegradable resin, making it possible to produce a more practical biodegradable resin composition. The moisture content is more preferably 8% by mass or less. Also, it is more preferably 7% by mass or less. Also, it is more preferably 6% by mass or less, and more preferably 5% by mass or less. The moisture content can be measured by the method described in the Examples.

[0033] When the median diameter of the biomass nanofiber particles is 3 to 15 μm, aggregates of biomass nanofibers are easily disintegrated in the resin during kneading with the resin, and the nanofibers can be well dispersed in the resin. The median diameter is more preferably 3 to 12 μm, and even more preferably 3 to 10 μm. The median diameter can be measured by the method described in the Examples.

[0034] The biomass nanofiber particles further preferably have a content of functional groups (ionic functional groups) selected from at least one of a carboxy group, a carboxymethyl group, a phosphate group, a sulfate group, a phosphite group, a xanthetic group, and a sulfo group of 0.1 mmol / g or less. By using the mechanically defibrated biomass nanofibers described above, the content of ionic functional groups can be reduced to 0.1 mmol / g or less.

[0035] In the biomass nanofiber particles, the content of the ionic functional group is 0.1 mmol / g or less, which can improve discoloration when kneaded with a resin and the heat resistance of the cellulose itself. The content of the ionic functional group is more preferably 0.08 mmol / g or less, and even more preferably 0.02 mmol / g or less. The content of the ionic functional group can be measured by the method described in the Examples. It is more preferable that the total content of all the ionic functional groups described above is within the above range.

[0036] In terms of dispersibility in resin, strength, and impact resistance, the BET specific surface area of ​​the biomass nanofiber particles is set to 70 to 200 m. 2 / g, and 90 to 150m 2 It is more preferable that the molecular weight is / g.

[0037] The biomass nanofiber particles of this embodiment can be produced by preparing a BNF dispersion and then drying the BNF, etc.

[0038] (Preparation of BNF Dispersion) First, a slurry of biomass nanofibers dispersed in water is prepared as a biomass dispersion fluid. For example, when the BNF according to this embodiment is CNF, it is a fiber obtained by mechanically crushing cellulose. Examples of cellulose include wood pulp with cellulose of type I crystal form (cellulose type I), non-wood pulp such as cotton, linter, hemp, bacterial cellulose, and parenchyma cell fiber, and regenerated cellulose fibers using N-methylmorpholine N-oxide / water solvent, cuprammonium complex, and sodium hydroxide / carbon disulfide as a dissolving agent with cellulose of type II crystal form (cellulose type II). Cellulose type II has a lower molecular weight and crystallinity, so that the fibers are more easily cut than cellulose type I, and also has a lower heat resistance, so cellulose type I is a preferred material. As a method for mechanically crushing raw cellulose, a method is known in which the pulp is cut to a predetermined length using a beater or refiner, and then mechanically crushed by fibrillating or pulverizing using a high-pressure homogenizer, grinder, impact crusher, bead mill, or the like.

[0039] The BNF is preferably obtained by defibrating a biomass dispersion fluid by jetting it through a jet nozzle having a diameter of 0.1 to 0.8 mm at a high pressure of 100 to 245 MPa against a hard body for impaction, by which the biomass dispersion fluid is jetted.

[0040] This fiber-opening method, like commercially available high-pressure homogenizers, allows continuous processing at high pressure by passing a biomass dispersion fluid through a narrow channel at high pressure and low speed, and not only by using shear force to homogenize the biomass when released, but also by using impact force by colliding with a hard body for impact and cavitation. The fiber-opening method using the shear force, impact force, and cavitation of a water jet (WJ) is defined as the WJ method. In addition, one collision process is considered to be one pass, and in order to obtain uniform nanofibers, it is necessary to perform repeated collisions preferably 1 to 30 passes, more preferably 5 to 20 passes.

[0041] In addition, since the above method does not require the use of acids or alkalis, it causes less damage to the molecular chains of cellulose, for example, and CNF with a high degree of crystallinity can be obtained. In the case of cellulose, the degree of crystallinity at each pass number (number of collisions) compared to untreated cellulose is 40 to 83%. In addition, the degree of crystallinity of chitin is 48 to 73%. In other physical grinding methods such as ball mills and disk mills, the degree of crystallinity decreases, but a major feature of the WJ method is that the degree of crystallinity is less likely to decrease.

[0042] Furthermore, in the WJ method, a high-concentration biomass dispersion fluid of up to 30 mass% can be defibrated by colliding it with a hard collision body using a high-pressure spray process of 100 to 245 MPa through a spray nozzle with a diameter of 0.1 to 0.8 mm.Compared to the commonly used process of producing nanofibers at 1 to 2 mass%, this dramatically improves the processing volume per solid content, making it possible to obtain BNF dispersions at low cost, with low environmental impact and high efficiency.

[0043] (Drying BNF) The drying of BNF is carried out by preheating the BNF dispersion or by mixing and stirring the BNF dispersion with an appropriate organic component in a drying device, and the drying rate is set to 0.0002-0.5 [kg / m] during the constant rate drying period (the period during the drying process in which the moisture content decreases at a constant rate over time in the process of drying food, etc. under constant heating conditions). 2 It is preferable to carry out the process under the condition of [.s].

[0044] In this case, the mass of the wet material before drying, ms [kg], changes over time θ [s], and the rate of decrease is expressed as rm [kg / s], which is expressed as rm = -dms / dθ. If the mass of the dry material is m [kg] and the mass of the moisture is mw [kg], then ms = m + mw. Since m remains constant during the drying process, it can be expressed as rm = -d(m + mw) / dθ = -dmw / dθ. Furthermore, the drying rate R is expressed as the area A [m 2 ] as the standard, R=-1 / A dmw / dθ=rm / A [kg / m 2 ·s].

[0045] The drying speed for drying the BNF produced by the WJ method is 0.0002 to 0.5 [kg / m 2 If the drying speed is within the range of 0.0002 [kg / m s], the particles will not aggregate strongly during drying and will be highly dispersible in the resin. 2 If the drying speed is less than 0.0002 to 0.5 [kg / m ·s], the dispersibility may decrease drastically. 2 The drying method for the conditions falling within the range of [1 / s] is not limited as long as the drying device can obtain the desired drying speed, and various commercially available drying devices can be used. For example, in addition to spray drying devices using the spray drying method, drying devices using the vacuum drying method, air flow drying devices using the air flow drying method, and fluidized bed drying devices using the fluidized bed drying method can be envisioned.

[0046] Spray drying is a method of producing dry powders by spraying a liquid or a mixture of liquid and solids (slurry) into a gas and rapidly drying it. Spray drying, also known as spray drying or spray drying, is suitable for drying materials that are easily damaged by heat, such as food and pharmaceuticals, and is used to dry products such as catalysts, as the dried product has a stable particle size distribution.

[0047] Vacuum drying is a method of drying objects under vacuum or reduced pressure. When the air pressure is reduced, the partial pressure of water vapor in the air decreases, lowering the boiling point of water and accelerating the evaporation rate, which can speed up the drying of objects.

[0048] Flash drying is a method in which powdery, wet, muddy, or lumpy materials are suspended in a high-velocity hot air current of 300-600℃ and transported while being rapidly dried in a matter of seconds. Hot air generally flows at about 10-30m / s inside the flash drying tube, resulting in good heat transfer efficiency.

[0049] Fluidized bed drying is a method of drying powder by injecting drying gas into it to fluidize it, taking advantage of the excellent mixing, gas contact, and heat transfer properties of the fluidized bed. The material to be dried is fed into one end of the fluidized chamber and discharged from the outlet while floating and flowing. The moving speed and fluid state of the material to be dried may be appropriately adjusted, and a partition may be inserted.

[0050] The spray dryer and conditions for spray drying may be, for example, those described in JP 2019-131772 A and JP 2019-131774 A, which produces biomass nanofiber particles having a moisture content of 10 mass% or less. The drying speed is set to 0.0002 to 0.5 kg / m 2 ·s] range, the moisture content of the biomass nanofiber particles can be made 9 mass% or less.

[0051] The storage temperature of the biomass nanofiber particles obtained by the above-mentioned production method is preferably 4 to 40° C., more preferably 4 to 30° C. The pressure is preferably normal pressure for storage. The humidity is preferably 70% or less, more preferably 60% or less. When storing the biomass nanofiber particles, it is preferable to add them to a bag such as an aluminum pouch or a sealable container, seal it, and then store it. The aluminum pouch or the sealed container can be transported in its original form. EXAMPLES

[0052] [Example 1] (Preparation of cellulose nanofiber particles) Ion-exchanged water was added to a CNF aqueous dispersion (BiNFi-s series WFo, degree of polymerization: 650, manufactured by Sugino Machine Ltd.) to adjust the final concentration to 1% by mass, thoroughly mixed and stirred using a Three-One Motor Mixer BLW3000 (manufactured by Shinto Scientific Co., Ltd.), and dried using a spray dryer to the properties shown in Table 1, yielding cellulose nanofiber particles as dried CNF. The cellulose nanofiber particles were in the form of particulate aggregates made up of multiple biomass nanofibers. The moisture content of the cellulose nanofiber particles was measured using a heat-drying moisture meter (manufactured by A&D, product name: MX-50) and was found to be 4.5% by mass. Furthermore, the properties of the produced cellulose nanofiber particles are shown in Table 1 below.

[0053] [Table 1]

[0054] The median diameter of the CNF particles was measured by a laser diffraction / scattering particle size distribution measurement method (Horiba, Ltd., device name: LA-960). The content of ionic functional groups in the CNF particles was measured by treating the biomass nanofiber aqueous dispersion with an ion exchange resin, and then measuring the content of ionic functional groups (total content of carboxy groups, carboxymethyl groups, phosphate groups, sulfate groups, phosphite groups, xanthete groups, and sulfo groups) using a conductometric titration method in which the change in electrical conductivity is determined while adding an aqueous sodium hydroxide solution. In the above table, the cellulose crystal structure was measured using an X-ray diffractometer (manufactured by Rigaku Corporation, device name: Rotary Anode X-ray Generator Rotaflex RU-200B) with an accelerating voltage of 40 kV, an accelerating current of 150 mA, and CuKα radiation (A=1.542) passed through a Ni filter, using a horizontal goniometer for powder X-ray diffraction manufactured by the same company. The diffraction intensity was measured over a diffraction angle 2θ range of 5° to 35°. The presence or absence of cellulose type I crystals was confirmed by checking whether the diffraction profile (wide-angle X-ray diffraction image) obtained by measuring the wide-angle X-ray diffraction image of cellulose fiber had peaks at two positions, near scanning angles 2θ=14-17° and 2θ=22-23°, which are due to typical cellulose type I crystals.

[0055] (Preparation of Resin Composition) Cellulose nanofiber particles (CNF particles), polylactic acid (TE-1030, manufactured by Unitika Co., Ltd.), heat stabilizer (Irganox 168, manufactured by BASF Japan), and antioxidant (Irgafos 1010, manufactured by BASF Japan) were mixed in the ratios shown in Table 2, and mixed at 20,000 rpm for 1 minute using a blender. The mixture was then melt-mixed at 250 ° C., 100 rpm, and kneaded for 5 minutes using a twin-screw kneader, and injection molded (molding temperature 250 ° C., mold temperature 40 ° C.) to obtain dumbbell pieces (ASTM D638 standard TYPE-1) with a length of 150 mm, a maximum width of 20 mm, a minimum width of 13 mm, and a thickness of 3.3 mm, and a Charpy impact test piece (JIS K7139 rectangular TYPE-B1) with a length of 80 mm, a width of 10 mm, and a thickness of 4 mm. Each test piece corresponds to a resin composition.

[0056] (evaluation) The resin composition thus obtained was subjected to the following evaluations. The evaluations were carried out at room temperature (23° C.). The results are shown in the table below.

[0057] Tensile strength (tensile modulus) The dumbbell pieces were conditioned for 7 days and then subjected to a tensile test using a precision universal testing machine (Shimadzu Corporation, product name: Autograph AG-Xplus). The test conditions were set to a test speed of 10 mm / min and a gripping distance of 60 mm. Measurements were performed in accordance with JIS K7161.

[0058] Charpy impact value The prepared Charpy impact test specimens were used to carry out a Charpy impact test. The Charpy impact value was evaluated by a notched Charpy test (notch shape: Type A notch (notch radius 0.25 mm)). The measurement was in accordance with JIS K7111, and a digital impact tester (DG-UB manufactured by Toyo Seiki Seisakusho) was used as the measuring device, the impact speed was 2.9 m / s, the nominal pendulum energy was 2 J or 4 J, the number of test pieces n = 5, and the evaluation item was absorbed energy.

[0059] [Examples 2 to 5, Comparative Example 1] A resin composition was prepared in the same manner as in Example 1 except for the proportions shown in Table 2. Then, evaluations were carried out in the same manner as in Example 1. The results are shown in the table below.

[0060] [Table 2]

[0061] In the present examples and comparative examples, TE-1030 manufactured by Unitika Ltd. was used as the polylactic acid, but other polylactic acid products (for example, Lacia manufactured by Mitsui Chemicals, Inc., Ingeo manufactured by NatureWorks, etc.) may also be used.

Claims

1. A biodegradable resin composition comprising biomass nanofibers and a biodegradable resin, wherein the content of the biomass nanofibers is 0.1 to 10% by mass.

2. The biodegradable resin composition according to Claim 1, wherein the content of the biomass nanofibers is 0.8 to 8% by mass.

3. The biodegradable resin composition according to Claim 1, wherein the biomass nanofibers are mechanically defibrated biomass nanofibers.

4. The biodegradable resin composition according to Claim 1, wherein the degree of polymerization of the biomass nanofibers is 150 to 900.

5. Biomass nanofiber particles for the biodegradable resin composition according to any one of Claims 1 to 4, comprising biomass nanofibers, wherein the biomass nanofiber particles are in the form of particles as an aggregate composed of a plurality of the biomass nanofibers having an average fiber diameter of 5 to 50 nm, the degree of polymerization of the biomass nanofibers is 150 to 900, the water content is 9% by mass or less, and the median diameter is 3 to 15 μm.

6. The biomass nanofiber particles according to Claim 5, wherein the content of a functional group selected from at least any one of a carboxy group, a carboxymethyl group, a phosphate group, a sulfate group, a phosphite group, a xanthate group, and a sulfo group is 0.1 mmol / g or less.