Resin composition

Abstract

A resin composition comprising: a biodegradable resin; and a cellulose structure containing cellulose and / or a cellulose derivative as a main component, the cellulose structure being present in the biodegradable resin at an average diameter of 50 [mu] m or less.

Description

Technical Field

[0001] The present invention relates to a resin composition. Background Art

[0002] Patent document 1 proposes "a polylactic acid or aliphatic polyester resin composition, characterized in that the nucleating agent is composed of a crystalline polysaccharide, the particle size of the nucleating agent is 500 μm or less and is composed of chitin, chitosan or crab shell, and the nucleating agent (b) is in the range of 0.1 to 10 parts by weight relative to 100 parts by weight of the polylactic acid or aliphatic polyester resin (a)".

[0003] Patent document 2 proposes "a biodegradable resin composition comprising a biodegradation accelerator, wherein the biodegradation accelerator comprises polysaccharides and / or monosaccharides, and the content of xylose in the biodegradation accelerator is 15% by mass or more. The biodegradation accelerator is contained in an amount of 1 part by mass or more and 250 parts by mass or less relative to 100 parts by mass of the biodegradable resin."

[0004] Patent document 3 proposes "a polylactic acid-based resin composition, characterized in that it is composed of a polymer component (A) containing polylactic acid (a1) and an aliphatic polyester (a2) having a melting point of 50 to 250°C and being biodegradable, wherein, based on the total weight of the polylactic acid (a1) and the aliphatic polyester (a2), it contains 90 to 50% by weight of the polylactic acid (a1) and 10 to 50% by weight of the aliphatic polyester (a2), and the biodegradable natural product (B) contains 0.1 to 100 parts by weight relative to 100 parts by weight of the polymer component (A)".

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2008-8158

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2022-21326

[0007] Patent Document 3: Japanese Patent Application Laid-Open No. 11-241009 Summary of the invention

[0008] The present invention aims to provide a resin composition comprising a biodegradable resin and a cellulose structure containing at least one of cellulose and a cellulose derivative as a main component, wherein in the resin composition, a resin molded body having excellent biodegradability and heat resistance can be obtained compared with a case where the cellulose structure is present in the biodegradable resin with an average diameter exceeding 50 μm.

[0009] Means for solving the above-mentioned problems include the following aspects.

[0010] <1>

[0011] A resin composition comprising:

[0012] Biodegradable resins; and

[0013] A cellulose structure comprising at least one of cellulose and a cellulose derivative as a main component,

[0014] The cellulose structure is present in the biodegradable resin with an average diameter of 50 μm or less.

[0015] <2>

[0016] The resin composition according to <1>, wherein the cellulose structure is a porous cellulose structure.

[0017] <3>

[0018] The resin composition according to <1> or <2>, wherein the cellulose and the cellulose derivative have a number average molecular weight of 15,000 to 50,000.

[0019] <4>

[0020] The resin composition according to any one of <1> to <3>, wherein the cellulose derivative is cellulose acetate.

[0021] <5>

[0022] The resin composition according to any one of <1> to <4>, wherein the content of the cellulose structure relative to the biodegradable resin is 0.1% by mass or more and 10% by mass or less.

[0023] <6>

[0024] The resin composition according to any one of <1> to <5>, wherein the resin composition has a deflection temperature under load (HDT) of 140° C. or higher.

[0025] <7>

[0026] The resin composition according to any one of <1> to <6>, wherein the biodegradation rate measured by a method in accordance with ISO 14855-1:2012 is 30% or more within 28 days.

[0027] <8>

[0028] The resin composition according to any one of <1> to <7>, wherein the biodegradable resin is at least one selected from the group consisting of polylactic acid, polybutylene succinate, polybutylene succinate adipate, cellulose acetate, and cellulose acetate propionate.

[0029] Effects of the Invention

[0030] According to the invention involved in <1>, <6>, <7> or <8>, there is provided a resin composition comprising a biodegradable resin and a cellulose structure containing at least one of cellulose and a cellulose derivative as a main component, wherein in the resin composition, a resin molded body excellent in biodegradability and heat resistance can be obtained compared to a case where the cellulose structure is present in the biodegradable resin with an average diameter exceeding 50 μm.

[0031] According to the invention as set forth in <2>, there is provided a resin composition capable of obtaining a resin molded body having excellent biodegradability and heat resistance compared to a case where the cellulose structure is a cellulose non-porous structure.

[0032] According to the invention as set forth in <3>, there is provided a resin composition capable of obtaining a resin molded article having excellent biodegradability and heat resistance compared to a case where the number average molecular weight of cellulose or the cellulose derivative is less than 15,000 or exceeds 50,000.

[0033] According to the invention as set forth in <4>, there is provided a resin composition capable of obtaining a resin molded body having excellent biodegradability and heat resistance compared to a case where the cellulose derivative is cellulose acetate propionate.

[0034] According to the invention of <5>, there is provided a resin composition capable of obtaining a resin molded article having excellent biodegradability and heat resistance compared to a case where the content of a cellulose structure relative to a biodegradable resin is less than 0.1% by mass or exceeds 10% by mass. DETAILED DESCRIPTION

[0035] Hereinafter, an embodiment as an example of the present invention will be described. These descriptions and examples are for illustrative purposes only and do not limit the scope of the invention.

[0036] In the numerical ranges described in this specification, the upper limit or lower limit described in one numerical range can be replaced by the upper limit or lower limit of the numerical range described in another stage. In addition, in the numerical ranges described in this specification, the upper limit or lower limit of the numerical range can be replaced by the value shown in the examples.

[0037] Each component may contain a plurality of corresponding substances.

[0038] When referring to the amount of each component in a composition, if there are plural substances corresponding to each component in the composition, unless otherwise specifically stated, the amount refers to the total amount of the plural substances present in the composition.

[0039] <Resin composition>

[0040] The resin composition according to this embodiment includes:

[0041] Biodegradable resins; and

[0042] A cellulose structure comprising at least one of cellulose and a cellulose derivative as a main component,

[0043] The cellulose structure is present in the biodegradable resin with an average diameter of 50 μm or less.

[0044] The cellulose structure is, for example, a powder containing at least one of cellulose and a cellulose derivative as a main component.

[0045] The resin composition according to the present embodiment can obtain a resin molded product having excellent biodegradability and heat resistance due to the above-mentioned structure. The reason for this is presumed to be as follows.

[0046] In recent years, due to environmental awareness represented by SDGs (Sustainable Development Goals), interest in biodegradable resins has been increasing. In particular, among biodegradable resins, polylactic acid is a carbon-neutral, highly biodegradable resin and is highly anticipated as a substitute for petroleum-derived plastics. However, biodegradable resins, especially polylactic acid, have low heat resistance and their uses are limited.

[0047] If petroleum-based resins and modifiers are compounded in biodegradable resins, heat resistance can be improved, but this will reduce biomass, CO2 emissions, petroleum resources, and other environmental effects. In addition, biodegradability will be increasingly impaired.

[0048] Therefore, in the resin composition according to the present embodiment, the cellulose structure is finely present in the biodegradable resin with an average diameter of 50 μm or less.

[0049] By including a highly biodegradable cellulose structure in a biodegradable resin, the biodegradation rate of the entire resin composition can be increased. It is believed that since the biodegradation of the cellulose structure occurs preferentially, degradative enzymes and microorganisms are concentrated in the entire biodegradable resin, thereby accelerating the biodegradation rate of the biodegradable resin.

[0050] In addition, it is considered that the cellulose structure finely present in the biodegradable resin acts as a crystal nucleating agent in the biodegradable resin, and promotes crystallization of the biodegradable resin, thereby improving heat resistance.

[0051] From the above, it is presumed that the resin composition according to the present embodiment can obtain a resin molded body having excellent biodegradability and heat resistance.

[0052] Hereinafter, the resin composition according to the present embodiment will be described in detail.

[0053] (Biodegradable resin)

[0054] The biodegradable resin is a resin that is decomposed into water and carbon dioxide by microorganisms. Specifically, in the present embodiment, the biodegradable resin refers to a resin whose biodegradation rate under aerobic conditions is 5% or more within 28 days according to the method in accordance with ISO 14855-1:2012.

[0055] Examples of the biodegradable resin include polyester resins, natural polymers, and polyvinyl alcohol.

[0056] Examples of the polyester resin include aliphatic polyester resins and aliphatic aromatic polyester resins.

[0057] Examples of the aliphatic polyester resin include polylactic acid (PLA), polyglycolic acid (PGA), polyhydroxyalkanoate (PHA), polycaprolactone, polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), polybutylene adipate (PBA) and other polyhydroxyalkanoic acids; and the like.

[0058] Examples of the aliphatic aromatic polyester resin include polyadipate / butylene terephthalate copolymer resin (PBAT) and polyadipate / tetramethylene terephthalate copolymer resin.

[0059] Examples of the natural polymer include starch, cellulose, chitin, chitosan, gluten, gelatin, zein, soybean protein, collagen, and keratin.

[0060] Examples of the biodegradable resin include cellulose derivatives (cellulose acylate, cellulose ether, hydroxyalkyl cellulose, and carboxymethyl cellulose).

[0061] Examples of cellulose acylate include cellulose acetate (monoacetyl cellulose, diacetyl cellulose (DAC), triacetyl cellulose), cellulose acetate propionate (CAP), and cellulose acetate butyrate (CAB).

[0062] Among these biodegradable resins, from the viewpoint of environmental adaptability, as the biodegradable resin, for example, at least one selected from the group consisting of polylactic acid, polybutylene adipate, polybutylene succinate adipate, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), cellulose acetate and cellulose acetate propionate can be cited, and particularly preferred are resins corresponding to both biomass resins and biodegradable resins (particularly preferred is polylactic acid).

[0063] These biodegradable resins may be used alone or in combination of two or more.

[0064] The content of the biodegradable resin is, for example, preferably 50% by mass or more and 99.9% by mass or less, and more preferably 90% by mass or more and 99.9% by mass or less, based on the resin composition.

[0065] (Cellulose structure)

[0066] The cellulose structure contains at least one of cellulose and a cellulose derivative as a main component.

[0067] Here, “comprising at least one of cellulose and a cellulose derivative as a main component” means that the total content of cellulose and the cellulose derivative relative to the cellulose structure is 90% by mass or more, for example, preferably 95% by mass or more, 98% by mass or more, or 100% by mass.

[0068] Cellulose is a polymer compound formed by linear polymerization of multiple β-glucose molecules through glycosidic bonds.

[0069] On the other hand, examples of cellulose derivatives include cellulose acylate, cellulose ether, hydroxyalkyl cellulose, and carboxymethyl cellulose.

[0070] Among them, as the cellulose derivative, for example, cellulose acylate is preferred from the viewpoint of high biodegradability.

[0071] Cellulose acylate is a cellulose derivative in which at least a part of the hydroxyl groups in cellulose is substituted (acylated) by acyl groups. AC (R AC represents a hydrogen atom or a hydrocarbon group. ) structure group.

[0072] Cellulose acylate is, for example, a cellulose derivative represented by the following general formula (CA).

[0073] [Chemical formula 1]

[0074]

[0075] In the general formula (CA), A 1 , A 2 and A 3 Each independently represents a hydrogen atom or an acyl group, and n represents an integer greater than 2. 1 、nA 2 and n A 3 At least one of the A represents an acyl group. 1 They may be all the same, partly the same, or different from each other.2 And there are n A 3 They may be entirely the same, partially the same, or different from each other.

[0076] In A 1 , A 2 and A 3 In the acyl group represented by , the hydrocarbon group in the acyl group may be any of linear, branched, and cyclic, and is preferably linear or branched, and more preferably linear.

[0077] In A 1 , A 2 and A 3 In the acyl group represented, the hydrocarbon group in the acyl group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group, and for example, a saturated hydrocarbon group is more preferable.

[0078] A 1 , A 2 and A 3 The acyl group represented is preferably an acyl group having, for example, 1 to 6 carbon atoms. That is, as cellulose acylate, for example, a cellulose acylate having 1 to 6 carbon atoms in the acyl group is preferred.

[0079] A 1 , A 2 and A 3 The acyl group represented may be a group in which a hydrogen atom in the acyl group is substituted with a halogen atom (eg, a fluorine atom, a bromine atom, an iodine atom), an oxygen atom, a nitrogen atom or the like, but is preferably an unsubstituted group.

[0080] As A 1 , A 2 and A 3 Examples of the acyl group include formyl, acetyl, propionyl, butanoyl, acryloyl, hexanoyl, etc. Among them, as the acyl group, from the viewpoint of increasing the biodegradation rate of the resin particles, for example, an acyl group having 2 to 4 carbon atoms is more preferred, and an acyl group having 2 or 3 carbon atoms is further preferred.

[0081] Examples of cellulose acylate include cellulose acetate (monoacetate cellulose, diacetate cellulose (DAC), triacetate cellulose), cellulose acetate propionate (CAP), and cellulose acetate butyrate (CAB).

[0082] Cellulose acylate is preferably cellulose acetate, for example, from the viewpoint of high biodegradability.

[0083] From the viewpoint of biodegradability, the degree of substitution of cellulose acylate is, for example, preferably 1.7 to 2.9, more preferably 1.9 to 2.6, further preferably 2.0 to 2.5, particularly preferably 2.1 to 2.4.

[0084] The degree of substitution of cellulose acylate is an index indicating the degree to which the hydroxyl groups of cellulose are replaced by acyl groups. That is, the degree of substitution is an index indicating the degree of acylation of cellulose acylate. Specifically, the degree of substitution indicates the intramolecular average of the number of substitutions of 3 hydroxyl groups in the D-pyranose glucose unit of cellulose acylate by acyl groups. 1 H-NMR (manufactured by JMN-ECA / JEOL RESONANCE Inc.) was determined from the integrated ratio of the peaks of hydrogen derived from cellulose and hydrogen derived from acyl groups.

[0085] These cellulose derivatives may be used alone or in combination of two or more.

[0086] -Number average molecular weight of cellulose and cellulose derivatives-

[0087] The number average molecular weight of cellulose and cellulose derivatives is, for example, preferably 5,000 to 50,000, more preferably 10,000 to 50,000, and still more preferably 15,000 to 30,000.

[0088] When the number average molecular weight of cellulose and cellulose derivatives is 15,000 or more, the cellulose structure can be prevented from being finely pulverized before being kneaded with the resin. As a result, secondary aggregation after pulverization can be suppressed, and a nearly fine and uniform dispersion in the resin can be easily achieved, which can easily improve the biodegradability and heat resistance of the resin molded body.

[0089] When the number average molecular weight of cellulose and a cellulose derivative is 50,000 or less, a decrease in biodegradability can be suppressed.

[0090] The number average molecular weight of cellulose and cellulose derivatives was measured by gel permeation chromatography (differential refractometer Optilab T-rEX / manufactured by Wyatt Technology Corporation, multi-angle light scattering detector DAWN HELEOSII / manufactured by Wyatt Technology Corporation, columns TSKgel α-M and α-3000, 1 each / manufactured by TOSOH CORPORATION) using dimethylacetamide (with 0.1 M lithium chloride added) as solvent.

[0091] The cellulosic structure may contain other ingredients.

[0092] (Characteristics of Cellulose Structure)

[0093] -Average Diameter of Cellulose Structure in Biodegradable Resin-

[0094] The cellulose structure exists in the biodegradable resin with an average diameter of 50 μm or less, for example, more preferably with an average diameter of 5 μm or less, and further preferably with an average diameter of 1 μm or less.

[0095] When the cellulose structure is present in the biodegradable resin with an average diameter of 50 μm or less, the cellulose structure is finely dispersed in the resin, thereby improving the biodegradability and heat resistance of the resin composition.

[0096] In addition, from the viewpoint of fully utilizing the modifying ability of the cellulose resin to improve the biodegradability and heat resistance of the resin composition, the cellulose structure preferably exists in the biodegradable resin with an average diameter of, for example, 0.05 μm or more.

[0097] The average diameter of the cellulose structure in the biodegradable resin is measured as follows.

[0098] Cut the resin composition. Observe the cellulose structure of the cut surface of the resin composition by scanning electron microscope (SEM) at a magnification of 1000 times, and obtain SEM images. Read the SEM images into the image processing software "ImageJ", and calculate the circle equivalent diameter according to the area of ​​the cellulose structure. Then, calculate the average value of the circle equivalent diameters of 20 cellulose structures, and use it as the average diameter.

[0099] -Porous structure-

[0100] The cellulose structure may be a porous structure or a non-porous structure.

[0101] Among them, when a cellulose porous structure is used, the contact area with the biodegradable resin increases, and the biodegradability is easily improved. In addition, the modification ability is also improved, and the heat resistance is also easily improved.

[0102] -Specific surface area-

[0103] The specific surface area of ​​the cellulose structure is preferably, for example, 1 m 2 / g and above and 150m 2 / g or less, more preferably 10m 2 / g and above and 150m 2 / g or less, more preferably 20m 2 / g or more and 100m 2 / g.

[0104] If the specific surface area of ​​the cellulose structure is 0.1 m 2 / g or more, the modification ability of the cellulose structure can be fully exerted to improve the heat resistance.

[0105] If the specific surface area of ​​the cellulose structure is 150 m 2 / g or less, the cellulose structure can be prevented from being finely disintegrated before being kneaded with the resin. As a result, secondary aggregation after disintegration can be suppressed, and nearly fine and uniform dispersion in the resin can be achieved, thereby improving the biodegradability and heat resistance of the resin molded body.

[0106] The specific surface area of ​​the cellulose structure is a BET specific surface area, and is a value measured by automatic measurement using a specific surface area / pore size distribution measuring device (BELSORP MAXII MicrotracBEL Corp.) by a multi-point method. The measurement temperature was set to 77 K, and nitrogen was used as the adsorption gas.

[0107] Prior to the measurement, the sample (ie, cellulose structure) was vacuum dried at 100° C. for 24 hours as a pretreatment to remove water adsorbed in the pores of the sample.

[0108] -Porosity-

[0109] The porosity of the cellulose structure is, for example, preferably 10% to 50%, more preferably 15% to 50%, and even more preferably 20% to 50%.

[0110] When the porosity of the cellulose structure is 20% or more, the modifying ability of the cellulose structure is fully exerted, and the heat resistance is improved.

[0111] If the porosity of the cellulose structure is 50% or less, the cellulose structure can be prevented from being finely disintegrated before being kneaded with the resin. As a result, secondary aggregation after disintegration can be suppressed, and nearly fine and uniform dispersion in the resin can be achieved, thereby improving the biodegradability and heat resistance of the resin molded body.

[0112] The porosity of the cellulose structure is measured as follows.

[0113] The cellulose structure was observed by scanning electron microscopy (SEM) at a magnification of 25,000 times, and a SEM image was obtained. The SEM image was read into the image processing software "ImageJ" and binarized to obtain the overall area of ​​the cellulose structure and the area of ​​the pores. Then, the ratio of the pores of the cellulose structure to the overall area of ​​the cellulose structure was obtained to obtain the porosity of the cellulose structure.

[0114] This operation was performed 10 times, and the average value was calculated.

[0115] -proportion-

[0116] The specific gravity of the cellulose structure is preferably 0.5 g / cm 3 Above and 1.15g / cm 3 Below, more preferably 0.6 g / cm 3 Above 1g / cm 3 Below, more preferably 0.7 g / cm 3 Above and 0.9g / cm 3 the following.

[0117] When the specific gravity of the cellulose structure is within the above range, the cellulose structure can be easily dispersed in the resin in a nearly fine and uniform manner when kneading the cellulose structure with the resin, thereby improving the biodegradability and heat resistance of the resin molded article.

[0118] The specific gravity of the cellulose structure is measured as follows.

[0119] 30 g of the structure was used as a sample and an automatic densitometer (DSG-1 manufactured by Toyo Seiki Seisaku-sho, Ltd.) was used. The measurement was performed three times by a water substitution method except that the measurement liquid was changed from water to ethanol. The average value was taken as the measurement value.

[0120] (Method for producing cellulose structure)

[0121] The cellulose structure according to the present embodiment can be obtained, for example, by the following method.

[0122] (1) A cellulose derivative is added to a good solvent for the cellulose derivative, and then heated to obtain a solution A in which the cellulose derivative is dissolved in the good solvent.

[0123] (2) A poor solvent for the cellulose derivative is added to solution A to obtain solution B.

[0124] (3) Solution B is rapidly cooled to generate a gel-like substance of the cellulose derivative by phase separation.

[0125] (4) After washing the gel-like substance, drying is performed to obtain a cellulose porous structure having a cellulose derivative as a main component.

[0126] (5) The obtained cellulose porous structure can be crushed and sieved to remove coarse particles and agglomerates as needed. The crushing method is not particularly limited, and can be carried out, for example, by a dry pulverizing device such as a jet mill, a vibration mill, a ball mill, or a pin mill. The sieving method can be carried out, for example, by a known method such as a vibrating screen or a wind-powered sieving machine.

[0127] Here, by saponifying the gel-like substance (that is, by saponifying the cellulose derivative), cellulose or a cellulose porous structure containing cellulose and a cellulose derivative as a main component is obtained depending on the degree of saponification.

[0128] In order to obtain a cellulose non-porous structure, for example, there are methods such as a method of obtaining cellulose particles by a suspension emulsion method and a method of crushing cellulose acetate (DAC) raw material.

[0129] (Content of cellulose structure)

[0130] The content of the cellulose structure is, for example, preferably 0.1% by mass to 20% by mass, more preferably 0.1% by mass to 10% by mass, and further preferably 1% by mass to 5% by mass, based on the biodegradable resin.

[0131] When the content of the cellulose structure is within the above range, a resin molded product having sufficiently high biodegradability and heat resistance can be easily obtained.

[0132] (Other ingredients)

[0133] The resin composition according to this embodiment may contain other components.

[0134] Examples of other components include plasticizers, flame retardants, compatibilizers, release agents, lightfast agents, weatherproof agents, colorants, pigments, modifiers, anti-dripping agents, antistatic agents, hydrolysis inhibitors, fillers, reinforcing agents (glass fiber, carbon fiber, talc, clay, mica, glass flakes, ground glass, glass beads, crystalline silica, alumina, silicon nitride, aluminum nitride, boron nitride, etc.), acid acceptors (oxides such as magnesium oxide and aluminum oxide; metal hydroxides such as magnesium hydroxide, calcium hydroxide, aluminum hydroxide, and hydrotalcite; calcium carbonate; talc; etc.), reactive scavengers (for example, epoxy compounds, acid anhydride compounds, carbodiimide, etc.), and the like.

[0135] The content of other components is preferably 0% by mass or more and 5% by mass or less, respectively, based on the total amount of the resin composition. Here, "0% by mass" means that other components are not included.

[0136] (Characteristics of resin composition)

[0137] -Load Deflection Temperature (HDT)-

[0138] The load deflection temperature (HDT) of the resin composition according to the present embodiment is, for example, preferably 125° C. or higher, more preferably 140° C. or higher, and further preferably 150° C. or higher. However, from the viewpoint of molding processability, the load deflection temperature (HDT) is, for example, 200° C. or lower.

[0139] When the load deflection temperature (HDT) is within the above range, a resin molded body having sufficiently high heat resistance can be obtained.

[0140] (Biodegradation rate)

[0141] The resin composition according to the present embodiment has a biodegradation rate measured by a method according to ISO 14855-1:2012 JIS 14855-1 within 28 days of, for example, preferably 30% or more, more preferably 50% or more, and even more preferably 70% or more. However, from the viewpoint of shape retention, the biodegradation rate is, for example, 100% or less.

[0142] When the biodegradation rate is within the above range, a resin molded product having sufficiently high biodegradability can be easily obtained.

[0143] Here, the load deflection temperature (HDT) and the biodegradation rate are values ​​measured by the methods described in the "Examples" described later.

[0144] (Method for producing resin composition)

[0145] As the manufacturing method of the resin composition involved in the present embodiment, for example, a method of mixing a raw material cellulose structure and a biodegradable resin and performing melt kneading, etc. can be cited. As the mechanism of melt kneading, there is no particular limitation, and for example, a twin-screw extruder, a Henschel mixer, a Banbury mixer, a single-screw extruder, a multi-screw extruder, a kneader, etc. can be cited.

[0146] Then, by controlling the kneading conditions, a resin composition including the raw material cellulose structure and a disintegrated product (ie, cellulose structure) obtained by disintegrating the raw material cellulose structure through kneading with the biodegradable resin can be obtained.

[0147] Here, the raw material cellulose structure preferably has an average diameter of, for example, 1 μm to 500 μm (for example, preferably 1 μm to 355 μm, more preferably 1 μm to 150 μm).

[0148] When the average diameter of the raw material cellulose structure is 1 μm or more, the cellulose porous structure collapses when the raw material cellulose structure is kneaded with the resin, and the cellulose porous structure is easily dispersed in the resin in a nearly fine and uniform manner, thereby improving the biodegradability and heat resistance of the resin molded product.

[0149] If the average diameter of the raw material cellulose structure is 500 μm or less, the cellulose porous structure can be prevented from being finely disintegrated before being kneaded with the resin. As a result, secondary aggregation after disintegration can be suppressed, and a nearly fine and uniform dispersion in the resin can be easily achieved, thereby improving the biodegradability and heat resistance of the resin molded body.

[0150] The method for measuring the average diameter of the raw material cellulose structure is as follows.

[0151] The cellulose porous structure was observed by scanning electron microscopy (SEM) at a magnification of 250 times, and a SEM image was obtained. The SEM image was read into the image processing software "ImageJ", and the circle equivalent diameter was calculated based on the area of ​​the cellulose porous structure. Then, the average value of the circle equivalent diameters of 20 cellulose porous structures was calculated and used as the average diameter.

[0152] In addition, the structure of the raw material cellulose structure is the same as that of the above-mentioned cellulose structure except for the above-mentioned average diameter, and therefore the description thereof is omitted.

[0153] <Resin molded body>

[0154] The resin molded body according to the present embodiment includes the resin composition according to the present embodiment. That is, the resin molded body according to the present embodiment is composed of the same combination as the resin composition according to the present embodiment.

[0155] As a molding method of the resin molded article according to the present embodiment, an injection molded article obtained by injection molding can be mentioned from the viewpoint of high degree of freedom in shape.

[0156] The injection molding of the resin molded body according to the present embodiment can be performed using commercially available apparatuses such as NEX500 manufactured by NISSEI PLASTIC INDUSTRIAL CO., LTD., NEX150 manufactured by NISSEI PASTIC INDUSTRIAL CO., LTD., NEX7000 manufactured by NISSEI PASTIC INDUSTRIAL CO., LTD., PNX40 manufactured by NISSEI PASTIC INDUSTRIAL CO., LTD., and SE50D manufactured by Sumitomo Heavy Industries, Ltd.

[0157] The resin molded body of the present embodiment may be a resin molded body obtained by other molding methods, such as extrusion molding, blow molding, hot press molding, calendering molding, coating molding, casting molding, impregnation molding, vacuum molding, transfer molding, etc.

[0158] Examples of uses of the resin molded body according to the present embodiment include frames of electronic / electrical equipment or household appliances; various components of electronic / electrical equipment or household appliances; interior components of automobiles; building block assembly toys; plastic model kits; storage boxes for CD-ROMs or DVDs; tableware; beverage bottles; food trays; packaging materials; films; sheets, etc.

[0159] Example

[0160] Hereinafter, examples will be described, but the present invention is not limited to these examples. In the following description, "parts" and "%" are based on mass unless otherwise specified.

[0161] <Production of cellulose structure>

[0162] (Cellulose structure CS (1))

[0163] In a container, 5 parts by mass of cellulose acetate DAC (1) was added to 20 parts by mass of dimethylformamide to obtain a solution A, which was stirred at 90°C for 1 hour. After dissolving cellulose acetate in dimethylformamide in solution A, 25 parts by mass of hexanol were slowly added to solution A while stirring, and the obtained solution B was stirred for 1 hour. Then, solution B was immersed in ice water together with the container for rapid cooling, and a gel product of a cellulose structure was obtained by phase separation. The generated gel product was washed with 200 parts by mass of ethanol and vacuum dried at 50°C for 24 hours to obtain a cellulose structure. Then, the structure was crushed with a grinder and sieved with a 106 μm mesh to obtain a finely pulverized cellulose structure.

[0164] (Cellulose structure CS (2))

[0165] A cellulose structure CS(2) was obtained in the same manner as in the cellulose structure CS(1) except that the mesh diameter of the sieve was set to 38 μm.

[0166] (Cellulose structure CS (3))

[0167] A cellulose structure CS(3) was obtained in the same manner as in the cellulose structure CS(1) except that the amount of cellulose acetate was changed to 7.5 parts by mass.

[0168] (Cellulose structure CS (4))

[0169] A cellulose structure CS(4) was obtained in the same manner as in the cellulose structure CS(1) except that the amount of cellulose acetate was changed to 3.5 parts by mass.

[0170] (Cellulose structure CS (5))

[0171] A cellulose structure CS(5) was obtained in the same manner as in the cellulose structure CS(1) except that cellulose acetate DAC(1) was changed to DAC(2).

[0172] (Cellulose structure CS (6))

[0173] A cellulose structure CS(6) was obtained in the same manner as in the cellulose structure CS(1) except that cellulose acetate DAC(1) was changed to DAC(3).

[0174] (Cellulose structure CS (7))

[0175] A cellulose structure CS(7) was obtained in the same manner as in the cellulose structure CS(1) except that cellulose acetate DAC(1) was changed to DAC(4).

[0176] (Cellulose structure CS (8))

[0177] A cellulose structure CS(8) was obtained in the same manner as in the cellulose structure CS(1) except that cellulose acetate was changed to triacetyl cellulose.

[0178] (Cellulose structure CS (9))

[0179] A cellulose structure CS(9) was obtained in the same manner as in the cellulose structure CS(1) except that cellulose acetate was changed to cellulose acetate propionate.

[0180] (Cellulose structure CS (10))

[0181] A cellulose structure CS(10) was obtained in the same manner as in the cellulose structure CS(1) except that cellulose acetate was changed to cellulose acetate butyrate.

[0182] (Cellulose structure CS (11))

[0183] A cellulose structure CS(11) was obtained in the same manner as in the cellulose structure CS(1), except that the gel product was subjected to alkali saponification before being subjected to ethanol washing.

[0184] (Cellulose structure CS (12))

[0185] A cellulose structure CS(12) was obtained in the same manner as in the cellulose structure CS(1) except that the mesh diameter of the sieve was set to 212 μm.

[0186] (Cellulose structure CS (13))

[0187] A cellulose structure CS(13) was obtained in the same manner as in the cellulose structure CS(1) except that the amount of cellulose acetate was changed to 10.0 parts by mass.

[0188] (Cellulose structure CS (14))

[0189] A cellulose structure CS(14) was obtained in the same manner as in the cellulose structure CS(1) except that the amount of cellulose acetate was changed to 12.5 parts by mass.

[0190] (Cellulose structure CS (15))

[0191] A cellulose structure CS(15) was obtained in the same manner as in the cellulose structure CS(1) except that dimethylformamide was changed to 120 parts by mass and hexanol was changed to 370 parts by mass.

[0192] (Cellulose structure CS (16))

[0193] A cellulose structure CS(16) was obtained in the same manner as in the cellulose structure CS(1) except that cellulose acetate DAC(1) was changed to DAC(5).

[0194] (Cellulose structure CS (17))

[0195] A cellulose structure CS(17) was obtained in the same manner as in the cellulose structure CS(1) except that sieving after crushing was not performed.

[0196] (Cellulose structure CS (C1))

[0197] Cellulose acetate DAC (1) was crushed with a grinder and then sieved with a 106 μm sieve to obtain a cellulose structure (C1).

[0198] (Cellulose structure CS (C2))

[0199] 130 parts by mass of cellulose acetate DAC (1) was dissolved in 870 parts by mass of ethyl acetate. This was added to a dispersion obtained by dispersing 50 parts by mass of calcium carbonate in 500 parts by mass of pure water, and stirred for 3 hours. This was added to a dispersion obtained by dispersing 4 parts by mass of carboxymethyl cellulose and 200 parts by mass of methyl ethyl ketone in 600 parts by mass of pure water, and stirred for 5 minutes using a high-speed emulsifier. 10 g of sodium hydroxide was added thereto, and the mixture was stirred at 80° C. for 3 hours to remove ethyl acetate and methyl ethyl ketone. 10 g of dilute hydrochloric acid was added thereto, and the residue was filtered to obtain non-porous cellulose particles.

[0200] (Characteristics of Cellulose Structure)

[0201] The following properties of the obtained cellulose structure were measured according to the methods described above.

[0202] Average diameter of cellulose structure

[0203] ·Specific surface area of ​​cellulose structure (marked as "BET" in the table)

[0204] Porosity of cellulose structure

[0205] Specific gravity of cellulose structure

[0206] <Example 1 to Example 25, Comparative Example 1 to Comparative Example 3>

[0207] Under the conditions of the composition, barrel temperature and kneading torque shown in Table 1, each component was charged into a twin-screw extruder (TEM58SS manufactured by SHIBAURA MACHINE CO., LTD.), kneaded, cooled and cut to obtain resin pellets (equivalent to the resin composition).

[0208] <Evaluation>

[0209] (Dispersion diameter)

[0210] The average diameter of the cellulose structures present in the biodegradable resin (represented as "dispersion diameter" in the table) was measured according to the method described above.

[0211] (Biodegradation rate)

[0212] The obtained resin pellets were crushed by LaboMill (LM-05 manufactured by DALTON Corporation), sieved with a 100 μm mesh, and the passed fraction was recovered. The recovered product was subjected to aerobic biodegradation measurement according to ISO 14855-1:2012 to determine the biodegradation rate after 28 days.

[0213] (Load Deflection Temperature (HDT))

[0214] Under the conditions of barrel temperature, mold temperature and mold holding time shown in Table 1, the resin pellets of each example were loaded into an injection molding device (manufactured by NISSEIPLASTIC INDUSTRIAL CO., LTD., NEX500) to mold ISO multi-purpose dumbbell-shaped test pieces (test part width 8 mm×thickness 4 mm×length 110 mm).

[0215] The deflection temperature under load (HDT) of the obtained test piece at a load of 0.45 MPa was measured using an HDT measuring device (HDT-3 manufactured by Toyo Seiki Seisaku-sho, Ltd.) in accordance with ISO75-1:2020.

[0216] <Materials used>

[0217] The following describes in detail the materials used.

[0218] - Raw materials for additives -

[0219] DAC (1): "Trade name CA-398-3" manufactured by Eastman Chemical Company, cellulose diacetate, number average molecular weight Mn = 15000

[0220] DAC (2): "Trade name L20" manufactured by DAICEL CORPORATION, cellulose diacetate, number average molecular weight Mn = 15000

[0221] DAC (3): "Trade name L50" ​​manufactured by DAICEL CORPORATION, cellulose diacetate, number average molecular weight Mn = 50,000

[0222] DAC (4): "Trade name L70" manufactured by DAICEL CORPORATION, cellulose diacetate, number average molecular weight Mn = 75,000

[0223] DAC(5): Cellulose diacetate synthesized by our company, number average molecular weight Mn=13000

[0224] ·TAC: "Trade name LT-35" manufactured by DAICEL CORPORATION, triacetyl cellulose, number average molecular weight Mn = 50,000

[0225] CAP: "Trade name CAP-482-20" manufactured by Eastman Chemical Company, cellulose acetate propionate, number average molecular weight Mn = 72000

[0226] ·CAB: "Trade name CAB-381-20" manufactured by Eastman Chemical Company, cellulose acetate butyrate, number average molecular weight Mn = 85,000

[0227] CNF: "BiNFIS DRY" manufactured by SUGINO MACHINE LIMITED CO., LTD., cellulose nanofiber

[0228] -Biodegradable resin-

[0229] PLA: Polylactic acid (manufactured by NatureWorks LLC., Ingeo3001D)

[0230] PBS: Polybutylene succinate (Bio-PBS manufactured by PTT MCC Biochem Co., Ltd.)

[0231] PBSA: Polybutylene succinate adipate (Bio-PBSA manufactured by PTT MCC Biochem Co., Ltd.)

[0232] CAP: Cellulose acetate propionate (manufactured by Eastman Chemical Company, CAP-482-20) [Table 1-1]

[0233]

[0234] [Table 1-2]

[0235]

[0236] As can be seen from the above results, in the present example, a resin molded body (ie, a resin composition) having high biodegradability and heat resistance can be obtained compared with the comparative example.

[0237] In Example 1, even when the biodegradable resin was replaced with "poly(3-hydroxybutyrate-co-3-hydroxyvalerate)" or "poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)", the same results as in Example 1 were obtained in terms of high biodegradability and heat resistance.

[0238] This embodiment includes the following aspects. (1)

[0240] A resin composition comprising:

[0241] Biodegradable resins; and

[0242] A cellulose structure comprising at least one of cellulose and a cellulose derivative as a main component,

[0243] The cellulose structure is present in the biodegradable resin with an average diameter of 50 μm or less. (2)

[0245] The resin composition according to (1), wherein

[0246] The cellulose structure is a cellulose porous structure. (3)

[0248] The resin composition according to (1) or (2), wherein

[0249] The number average molecular weight of the cellulose and the cellulose derivative is 15,000 or more and 50,000 or less. (4)

[0251] The resin composition according to any one of (1) to (3), wherein

[0252] The cellulose derivative is cellulose acetate. (5)

[0254] The resin composition according to any one of (1) to (4), wherein

[0255] The content of the cellulose structure relative to the biodegradable resin is 0.1% by mass or more and 10% by mass or less. (6)

[0257] The resin composition according to any one of (1) to (5), wherein

[0258] The load deflection temperature (HDT) is 140°C or higher. (7)

[0260] The resin composition according to any one of (1) to (6), wherein

[0261] The biodegradation rate measured by the method according to ISO 14855-1:2012 is 30% or more within 28 days. (8)

[0263] The resin composition according to any one of (1) to (7), wherein

[0264] The biodegradable resin is at least one selected from the group consisting of polylactic acid, polybutylene succinate, polybutylene succinate adipate, cellulose acetate, and cellulose acetate propionate.

[0265] The effects of the above method are as follows.

[0266] According to the invention involved in (1), (6), (7) or (8), there is provided a resin composition comprising a biodegradable resin and a cellulose structure containing at least one of cellulose and a cellulose derivative as a main component, wherein in the resin composition, a resin molded body having excellent biodegradability and heat resistance can be obtained compared with a case where the cellulose structure is present in the biodegradable resin with an average diameter exceeding 50 μm.

[0267] According to the invention as set forth in (2), there is provided a resin composition capable of obtaining a resin molded body having excellent biodegradability and heat resistance compared to a case where the cellulose structure is a cellulose non-porous structure.

[0268] According to the invention as set forth in (3), there is provided a resin composition capable of obtaining a resin molded article having excellent biodegradability and heat resistance compared to the case where the number average molecular weight of cellulose and the cellulose derivative is less than 15,000 or exceeds 50,000.

[0269] According to the invention as set forth in (4), there is provided a resin composition capable of obtaining a resin molded body having excellent biodegradability and heat resistance compared to a case where the cellulose derivative is cellulose acetate propionate.

[0270] According to the invention as set forth in (5), there is provided a resin composition capable of obtaining a resin molded body having excellent biodegradability and heat resistance compared to a case where the content of a cellulose structure relative to a biodegradable resin is less than 0.1% by mass or exceeds 10% by mass.

[0271] The above-mentioned embodiments of the present invention are provided for the purpose of illustration and description. In addition, the embodiments of the present invention do not fully and exhaustively include the present invention, and do not limit the present invention to the disclosed methods. Obviously, various modifications and changes are self-evident to those skilled in the art to which the present invention belongs. The present embodiment is selected and described in order to most easily understand the principles of the present invention and its application. Thus, other technicians in the art can understand the present invention through various variations optimized for specific uses assumed to be various embodiments. The scope of the present invention is defined by the above claims and their equivalents.

Claims

1. A resin composition comprising: Biodegradable resins; and A cellulose structure comprising at least one of cellulose and a cellulose derivative as a main component, The cellulose structure is present in the biodegradable resin with an average diameter of 50 μm or less.

2. The resin composition according to claim 1, wherein The cellulose structure is a cellulose porous structure.

3. The resin composition according to claim 1 or 2, wherein The number average molecular weight of the cellulose and the cellulose derivative is 15,000 or more and 50,000 or less.

4. The resin composition according to any one of claims 1 to 3, wherein The cellulose derivative is cellulose acetate.

5. The resin composition according to any one of claims 1 to 4, wherein The content of the cellulose structure relative to the biodegradable resin is 0.1% by mass or more and 10% by mass or less.

6. The resin composition according to any one of claims 1 to 5, wherein The deflection temperature under load HDT is 140°C or higher.

7. The resin composition according to any one of claims 1 to 6, wherein The biodegradation rate measured by the method according to ISO 14855-1:2012 is 30% or more within 28 days.

8. The resin composition according to any one of claims 1 to 7, wherein The biodegradable resin is at least one selected from the group consisting of polylactic acid, polybutylene succinate, polybutylene succinate adipate, cellulose acetate, and cellulose acetate propionate.

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