Thermoplastic starch composition comprising starch and plasticizer for starch, and method for producing the same

Abstract

To provide a thermoplastic starch composition having flowability.SOLUTION: A thermoplastic starch composition of the present disclosure comprises starch and a plasticizer for starch. When the thermoplastic starch composition diluted to 15 wt.% with water is heated in a water bath to 95°C, stirred at 400 rpm for 20 minutes, dispersed using a homogenizer at 15,000 rpm for 1 minute, and then cooled in a water bath to 70°C, the viscosity is 270 mPa s or less as measured with a B-type viscometer.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to thermoplastic starch compositions, pellets, flakes, compound bodies, resin molded products, methods for producing thermoplastic starch compositions, methods for producing pellets or flakes, methods for producing compound bodies, and methods for producing resin molded products. [Background technology]

[0002] Recently, from the viewpoints of utilizing renewable materials and reducing carbon dioxide emissions, i.e., carbon circulation, and protecting the global environment through the widespread use of biodegradable resins, there is a demand to switch from conventional petroleum-derived resins to biomass-derived resins. Against this background, Patent Document 1 discloses a method of blending starch into a resin. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2011-522950 Summary of the Invention [Problem to be solved by the invention]

[0004] As disclosed in Patent Document 1, a composition simply made by mixing starch and a starch plasticizer may have significantly reduced fluidity. A composition with low fluidity is difficult to disperse in a thermoplastic resin, which can cause a deterioration in the physical properties of a resin molded product. Resin molded products produced using such compounds or compositions have limited physical properties and quality, which inevitably limits their applications.

[0005] Therefore, an object of the present disclosure is to provide a thermoplastic starch composition having fluidity, pellets, flakes, a compound body, a resin molded product, a method for producing a thermoplastic starch composition, a method for producing pellets or flakes, a method for producing a compound body, and a method for producing a resin molded product. [Means for solving the problem]

[0006] To achieve the above object, one embodiment of the thermoplastic starch composition of the present disclosure comprises: 1. A thermoplastic starch composition comprising: starch and a plasticizer for starch, The thermoplastic starch composition is diluted with water to 15% by weight, heated to 95°C in a water bath, heated and stirred at 400 rpm for 20 minutes, dispersed at 15,000 rpm for 1 minute using a homogenizer, and cooled to 70°C in a water bath. The viscosity measured with a Brookfield viscometer is 270 mPa s or less.

[0007] One aspect of the thermoplastic starch composition of the present disclosure comprises: starch and a plasticizer for starch, The total weight of all components other than water contained in the thermoplastic starch composition is taken as 100% by weight, The starch content is 60 to 95% by weight, The content of the starch plasticizer is 5 to 35% by weight, The thermoplastic starch composition has a melt flow rate of 0.01 g / 10 min or more at a temperature of 160° C. under a load of 5 kg according to JIS K 7210.

[0008] The pellets of the present disclosure comprise the thermoplastic starch composition of the present disclosure.

[0009] The flakes of the present disclosure comprise the thermoplastic starch composition of the present disclosure.

[0010] The compound body of the present disclosure comprises the thermoplastic starch composition of the present disclosure.

[0011] The molded resin article of the present disclosure comprises the thermoplastic starch composition of the present disclosure.

[0012] The method for producing the thermoplastic starch composition of the present disclosure includes: The method includes a mixing step of mixing raw materials containing the starch and the starch plasticizer.

[0013] The method of producing pellets or flakes of the present disclosure includes: a strand forming step of extruding the thermoplastic starch composition to form strands; and a strand cutting step of cutting the strands to form pellets or flakes, The thermoplastic starch composition is the thermoplastic starch composition of the present disclosure.

[0014] The method for producing a compound body according to the present disclosure includes: A first kneading step of kneading a raw material containing pellets or flakes with a raw material containing a thermoplastic resin, the pellets are pellets of the present disclosure; The flakes are flakes of the present disclosure.

[0015] The method for producing a resin molded product according to the present disclosure includes: A resin molding step of resin-molding a raw material including a compound body to produce a resin molded product, The compound body is the compound body of the present disclosure. [Effects of the Invention]

[0016] According to the present disclosure, a thermoplastic starch composition having fluidity can be obtained. DETAILED DESCRIPTION OF THE INVENTION

[0017] Preferred embodiments for carrying out the present disclosure will be disclosed below. However, the following embodiments disclose typical embodiments of the present disclosure, and the scope of the present disclosure is not limited to these embodiments.

[0018] In the present disclosure, unless otherwise specified, "mass %" and "wt %" may be read interchangeably, and "parts by mass" and "parts by weight" may be read interchangeably.

[0019] In the present disclosure, unless otherwise specified, the term "strand" refers to a general term for a thermoplastic starch composition extruded from various extruders, and the shape, such as length, is not particularly limited. For example, the term "strand" includes any shape extruded from various extruders, such as a long string-like one or a short plate-like one.

[0020] <Thermoplastic starch composition> First, the thermoplastic starch composition of the present disclosure will be described.

[0021] [viscosity] In one embodiment of the present disclosure, the thermoplastic starch composition is diluted with water to 15% by weight, heated to 95°C in a water bath, heated and stirred at 400 rpm for 20 minutes, dispersed using a homogenizer at 15,000 rpm for 1 minute, and cooled to 70°C in a water bath. The viscosity measured using a Brookfield viscometer (hereinafter sometimes simply referred to as "B-type viscosity") is 270 mPa s or less. The upper limit of the Brookfield viscosity may be, for example, 260 mPa·s or less, 250 mPa·s or less, 240 mPa·s or less, 230 mPa·s or less, 220 mPa·s or less, 210 mPa·s or less, 200 mPa·s or less, 190 mPa·s or less, or 180 mPa·s or less, and the lower limit may be, for example, 1 mPa·s or more, 3 mPa·s or more, 5 mPa·s or more, 10 mPa·s or more, 20 mPa·s or more, 30 mPa·s or more, 40 mPa·s or more, 50 mPa·s or more, 60 mPa·s or more, 70 mPa·s or more, or 80 mPa·s or more. The Brookfield viscosity can be measured by the measurement method described in the Examples below. The Brookfield viscosity can be adjusted by, for example, adjusting the compounding ratio of starch, compatibilizer, thermoplastic resin, starch plasticizer, or metal halide salt, which will be described later, or by adjusting production conditions such as the production temperature or kneading time during production.

[0022] When the B-type viscosity is 270 mPa·s or less, a thermoplastic starch composition exhibiting high fluidity can be obtained. For example, the present disclosure is useful when a compound body having a high starch content and a high breaking elongation is desired. However, when the starch content is increased, a compound body containing a thermoplastic starch composition having a high B-type viscosity tends to have a lower breaking elongation.

[0023] The thermoplastic starch composition of the present disclosure may have a viscosity X calculated by the following formula (1) of 270 mPa·s or less. X=A+(73-B)×6.57 (1) In the formula (1), A is the viscosity (the B-type viscosity) measured using a B-type viscometer after adding the thermoplastic starch composition to water so that the concentration becomes 15% by weight, heating the mixture in a water bath to 95°C, heating and stirring the mixture at 400 rpm for 20 minutes, dispersing the mixture using a homogenizer at 15,000 rpm for 1 minute, and cooling the mixture in a water bath to 70°C; B is the content of the starch when the total weight of all components other than water contained in the thermoplastic starch composition is taken as 100% by weight.

[0024] The upper limit of the viscosity X may be, for example, 260 mPa·s or less, 250 mPa·s or less, 240 mPa·s or less, 230 mPa·s or less, 220 mPa·s or less, 210 mPa·s or less, 200 mPa·s or less, 190 mPa·s or less, or 180 mPa·s or less, and the lower limit may be, for example, 1 mPa·s or more, 3 mPa·s or more, 5 mPa·s or more, 10 mPa·s or more, 20 mPa·s or more, 30 mPa·s or more, 40 mPa·s or more, 50 mPa·s or more, 60 mPa·s or more, 70 mPa·s or more, or 80 mPa·s or more.

[0025] The viscosity X is the Brookfield viscosity value when the starch content is converted to 73% by weight. When the viscosity X is 270 mPa·s or less, a thermoplastic starch composition exhibiting high fluidity can be obtained. For example, the present disclosure is useful when a compound body having a high starch content and a high breaking elongation is desired. Note that when the starch content is increased, a compound body containing a thermoplastic starch composition with a high viscosity X tends to have a lower breaking elongation.

[0026] Melt Flow Rate (MFR) In one embodiment of the present disclosure, the thermoplastic starch composition has a melt flow rate (MFR) of 0.01 g / 10 min or more at a temperature of 160° C. under a load of 5 kg according to JIS K 7210. The lower limit of the MFR may be, for example, 0.01 g / 10 min or more, 0.02 g / 10 min or more, 0.05 g / 10 min or more, 0.1 g / 10 min or more, 0.2 g / 10 min or more, 0.5 g / 10 min or more, 1.0 g / 10 min or more, 2.0 g / 10 min or more, 3.0 g / 10 min or more, or 4.0 g / 10 min or more, and the upper limit may be, for example, 200 g / 10 min or less, 170 g / 10 min or less, 150 g / 10 min or less, 120 g / 10 min or less, 100 g / 10 min or less, 80 g / 10 min or less, 50 g / 10 min or less, 30 g / 10 min or less, 20 g / 10 min or less, or 15 g / 10 min or less. The MFR can be measured by the measurement method described in the Examples below. The MFR can be adjusted by, for example, adjusting the compounding ratio of starch, compatibilizer, thermoplastic resin, starch plasticizer, or metal halide salt, which will be described later, or by adjusting production conditions such as the production temperature or kneading time during production.

[0027] When the thermoplastic starch composition of the present disclosure has an MFR of 0.01 g / 10 min or more, it is possible to obtain a thermoplastic starch composition exhibiting high fluidity. For example, the present disclosure is useful when a compound body having a high starch content and a high breaking elongation is desired. However, when the starch content is increased, a compound body containing a thermoplastic starch composition with a low MFR tends to have a lower breaking elongation.

[0028] [starch] Examples of the starch include unmodified starches obtained from corn, potato, sweet potato, cassava, sago palm, rice, wheat, etc. Specifically, examples include corn starch, waxy corn starch, high-amylose corn starch, potato starch, sweet potato starch, tapioca starch, sago starch, rice starch, wheat starch, etc. Further examples include processed starches obtained by etherifying or esterifying unmodified starches, or by crosslinking, etc. One type of starch may be used alone, or two or more types may be used in combination. From the viewpoint of production costs, the unmodified starch is preferably corn starch or tapioca starch, and more preferably corn starch.

[0029] The moisture content of the starch used in the present disclosure is not particularly limited, but is, for example, 5 to 25% by weight, more preferably 7 to 23% by weight, even more preferably 9 to 20% by weight, and most preferably 10 to 18% by weight.

[0030] The starch content is, for example, 60 wt% or more, more preferably 65 wt% or more, and even more preferably 70 wt% or more, based on 100 wt% of the total weight of all components other than water contained in the thermoplastic starch composition, in order to improve the biomass ratio. From the viewpoint of dispersing the starch by mixing with a thermoplastic resin, the starch content is 95 wt% or less, preferably 90 wt% or less, more preferably 80 wt% or less, and most preferably 75 wt% or less, based on 100 wt% of the total weight of all components other than water contained in the thermoplastic starch composition, and is in the range of, for example, 60 to 95 wt%, more preferably 60 to 85 wt%, even more preferably 60 to 80 wt%, and most preferably 65 to 75 wt%. In the present disclosure, even when the starch content is as high as 60 wt% or more, a high MFR of 0.01 g / 10 min or more exhibits high fluidity, facilitating kneading with a thermoplastic resin or the like.

[0031] The starch may be, for example, a degraded starch. By using the degraded starch, the thermoplastic starch composition can be easily dispersed in a resin, and a resin molded product having the desired properties or quality can be obtained. The degraded starch is, for example, a starch that has been subjected to a degrading treatment by the treatment method described below.

[0032] The starch treatment method for producing the low-molecular-weight starch is not particularly limited, and examples thereof include chemical low-molecular-weight treatments such as acid treatment, alkali treatment, oxidation treatment, radical treatment, enzyme treatment, and mixing with metal salts; and physical low-molecular-weight treatments that involve applying energy to starch, such as heat treatment, radiation treatment, electron beam treatment, microwave treatment, ultrasonic treatment, high-frequency treatment, pressure treatment, milling treatment, powder collision treatment, friction treatment, pulverization treatment, extrusion treatment, and gelatinization treatment. Examples of the metal salt include metal halide salts, which will be described later. The treatment methods are preferably acid treatment, alkali treatment, oxidation treatment, enzyme treatment, mixing with metal salts, heat treatment, pulverization, and extrusion, which are easy to perform and inexpensive. The treatment methods may be any one of these treatment methods, or two or more of these treatment methods may be used in combination. The low-molecular-weight starch obtained by the chemical low-molecular-weight treatment is preferably washed after the low-molecular-weight treatment, for example, to reduce damage to the equipment used. That is, the depolymerized starch is preferably a washed depolymerized starch. The washing method is, for example, washing with water. The number of times of washing is not particularly limited.

[0033] The decrease in molecular weight due to the depolymerization of starch can be confirmed by known methods such as gel filtration chromatography and multi-angle light scattering, and can also be confirmed by measuring the viscosity of the starch after the depolymerization.

[0034] The starch before the molecular weight reduction treatment can be a conventionally known starch, and examples thereof include unmodified starches such as corn starch, waxy corn starch, wheat starch, potato starch, tapioca starch, sago starch, etc. Furthermore, examples of the starch before the molecular weight reduction treatment include chemically modified starches that have been subjected to esterification treatment, etherification treatment, crosslinking treatment, etc., physically modified starches that have been subjected to granulation treatment, moist heat treatment, hot water treatment, bleaching treatment, sterilization treatment, etc., and modified starches obtained by performing any two or more of the above treatments.

[0035] [Starch plasticizer] In this disclosure, unless otherwise specified, the term "starch plasticizer" refers to a plasticizer used to plasticize starch, and does not refer to a starch-free plasticizer commonly used by those skilled in the art to adjust the physical properties of thermoplastic resins.

[0036] The starch plasticizer is not particularly limited as long as it is a substance that substantially plasticizes the starch, excluding water. Examples of the starch plasticizer include polyhydric alcohols, sugars, ammonia, ureas, and ionic liquids. Examples of the polyhydric alcohols include glycerol (glycerin), ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-heptanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nanonediol, 1,10-decanediol, 1,12-dodecanediol, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, and diglycerol. Examples of the sugars include sorbitol, glucose, maltitol, mannitol, and erythritol. These may be used alone or in combination. These substances may be incorporated into the starch in advance, for example. Furthermore, when a thermoplastic resin described below is contained, these substances may be incorporated into the thermoplastic resin in advance. Furthermore, these substances may be incorporated at any timing during the preparation of the thermoplastic starch composition of the present disclosure.

[0037] The starch plasticizer used in the present disclosure is preferably glycerin, propylene glycol, or sorbitol, more preferably glycerin, from the viewpoint of the effect of plasticizing starch.

[0038] The content of the starch plasticizer is, for example, 5 to 35% by weight, preferably 10 to 35% by weight, more preferably 10 to 30% by weight, even more preferably 15 to 30% by weight, and most preferably 20 to 30% by weight, where the total weight of all components other than water contained in the thermoplastic starch composition is 100% by weight.

[0039] It is preferable that the starch plasticizer is substantially free of water. In other words, it is preferable that the starch plasticizer is not primarily composed of water. This is because, for example, when water is used as the primary component of the starch plasticizer, foaming occurs due to water evaporation during the production of the thermoplastic starch composition or during the molding of the compound body described below. For example, when the thermoplastic starch composition is produced using an extruder, unintentional foaming of the thermoplastic starch composition at the extruder outlet may result in reduced productivity. Furthermore, during the typical production of the thermoplastic starch composition or during the molding of the compound body described below, high-temperature conditions of 100°C or higher and the removal of gas by vacuum degassing are involved, increasing the possibility that plasticizers with low boiling points, such as water, may be discharged outside the system. As a result, the starch plasticizer component contained in the thermoplastic starch composition before strand formation may decrease in volume compared to before the kneading, causing the thermoplasticity of the starch to be lost and significantly reducing the dispersibility of the starch in the thermoplastic starch composition.

[0040] [Thermoplastic resin] The thermoplastic starch composition of the present disclosure may or may not further contain a thermoplastic resin. Furthermore, as described below, a compound can be obtained by kneading the thermoplastic starch composition of the present disclosure and the thermoplastic resin. The thermoplastic resin is not particularly limited, and for example, a commonly known thermoplastic resin can be used. Furthermore, for example, a biodegradable thermoplastic resin can be used. Examples of the thermoplastic resin include polyolefin-based resins, which are polymers of olefins having 2 to 20 carbon atoms, such as polypropylene, polybutene, polypentene, and polyethylene; polycyclic olefin-based resins such as polynorbornene; polystyrene-based resins such as polystyrene and ABS resin; and polyester-based resins such as polylactic acid, polyethylene terephthalate, polybutylene terephthalate, and polybutylene succinate, and mixtures thereof are also acceptable. Examples of the polyethylene include linear low-density polyethylene, low-density polyethylene, very low-density polyethylene, medium-density polyethylene, and high-density polyethylene. Furthermore, it may be a copolymer, such as an ethylene-propylene (block and random) copolymer, an ethylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymer, a propylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymer, an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid copolymer, etc. The thermoplastic resin may be used alone or in combination of two or more kinds.

[0041] The thermoplastic resin is preferably, for example, polyethylene or polypropylene from the viewpoint of versatility, and more preferably polyethylene.

[0042] The content of the thermoplastic resin is not particularly limited, but is preferably high, e.g., 0% by weight, in consideration of improving the biomass content. Furthermore, when the thermoplastic resin is contained, the total weight of all components other than water contained in the thermoplastic starch composition is taken as 100% by weight, and the lower limit is, for example, more than 0% by weight, and the upper limit is 30% by weight or less, more preferably 20% by weight or less, even more preferably 10% by weight or less, and most preferably 5% by weight or less.

[0043] [Metal halide salts] The metal halide salt used in the present disclosure may be, for example, a known metal halide salt. The metal halide salt may include, for example, at least one selected from the group consisting of metal chlorides, metal bromides, and metal iodides. The fluidity-imparting effect of a thermoplastic starch composition, described below, depends, for example, on the amount of the metal halide salt contained in the thermoplastic starch composition. The greater the amount of the metal halide salt contained in the thermoplastic starch composition, the greater the fluidity-imparting effect. Therefore, the metal halide salt preferably includes at least one of a metal chloride salt and a metal bromide salt, which contain more molecules (i.e., have a smaller molar mass) at the same weight of the metal halide salt, and more preferably includes a metal chloride salt. The metal halide salt may be, for example, at least one selected from the group consisting of sodium chloride, magnesium chloride, calcium chloride, aluminum chloride, sodium bromide, magnesium bromide, calcium bromide, sodium iodide, magnesium iodide, and calcium iodide.

[0044] The form of the metal halide salt is not particularly limited, and may be, for example, a solid such as a powder, or a liquid such as an aqueous solution. From the viewpoint of dispersion in the starch raw material, the liquid form is preferred.

[0045] The content of the metal halide salt is, for example, 0.1 to 10% by weight, more preferably 0.2 to 8% by weight, even more preferably 0.25 to 7% by weight, and most preferably 0.3 to 5% by weight.

[0046] Here, thermoplastic starch compositions that do not contain the metal halide salt, such as those produced by mixing the starch (particularly the starch before the low-molecular-weight treatment) with the starch plasticizer, tend to have a high B-type viscosity (i.e., low fluidity). This is presumably why they are difficult to disperse when kneaded with the thermoplastic resin described below, resulting in a deterioration in the physical properties of the compound. Meanwhile, the inventors of the present disclosure have found that mixing a mixture containing the starch, the starch plasticizer, and the metal halide salt under heating reduces the B-type viscosity of the thermoplastic starch composition (i.e., increases fluidity). From this, it is presumed that the metal halide salt imparts high fluidity to the thermoplastic starch composition by plasticizing the starch or changing its structure. However, this is merely a hypothesis, and the present disclosure is not limited thereto.

[0047] [Compatibilizer] The thermoplastic starch composition of the present disclosure may or may not further contain a compatibilizer. The compatibilizer is not particularly limited, and any commonly known compatibilizer can be used. Examples include compounds containing one or more compounds selected from the group consisting of compounds having an acid anhydride group (e.g., maleic anhydride, succinic anhydride, glutaric anhydride), compounds having a carboxyl group (e.g., maleic acid, succinic acid, glutaric acid), compounds having an epoxy group, compounds having an imino group, compounds having an isocyanate group, compounds having an oxazoline group, and silane coupling agents having a reactive group (e.g., an alkoxy group). Acid anhydride groups, epoxy groups, imino groups, and isocyanate groups are functional groups that can react with hydroxy groups, and compounds having such functional groups are preferred as compatibilizers in the present disclosure. Examples of compounds that can be used as compatibilizers include polymer compounds having the above-mentioned functional groups, such as polyolefin-based, acrylic-based, and styrene-based polymer compounds. To ensure compatibility with the resin to be blended, polyolefin-based polymer compounds having such functional groups are preferred.

[0048] Examples of the polyolefin polymer compound include ethylene polymers (high-density polyethylene, medium-density polyethylene, low-density polyethylene, copolymers of ethylene and one or more other vinyl compounds (e.g., α-olefin, vinyl acetate, methacrylic acid, acrylic acid, etc.)), propylene polymers (polypropylene, copolymers of propylene and one or more other vinyl compounds), ethylene-propylene copolymers, polybutene, and poly-4-methylpentene-1, with ethylene polymers and propylene polymers being preferred. Specific examples of the polyolefin polymer compound having such functional groups include maleic anhydride-modified polyolefins, more specifically maleic anhydride-modified polyethylene and maleic anhydride-modified polypropylene.

[0049] When the thermoplastic starch composition of the present disclosure contains a compatibilizer, the content of the compatibilizer is, for example, 0.1 to 10 wt%, where the total weight of all components other than water contained in the thermoplastic starch composition is 100 wt%. The content of the compatibilizer may have a lower limit of 0.1 wt% or more, 0.5 wt% or more, or 1 wt% or more, and an upper limit of 10 wt% or less or 8 wt% or less, where the range is, for example, preferably 0.1 to 10 wt%, more preferably 0.1 to 8 wt%, even more preferably 0.5 to 8 wt%, and most preferably 1 to 8 wt%, where the total weight of all components other than water contained in the thermoplastic starch composition is 100 wt%.

[0050] [Other additives] The thermoplastic starch composition of the present disclosure may or may not further contain various conventionally known additives. Examples of the additives include emulsifiers, elastomers, inorganic fillers, heat stabilizers, light stabilizers, UV absorbers, antistatic agents, etc. These may be used alone or in combination of two or more. Furthermore, these substances may be incorporated into the starch in advance. Furthermore, when a thermoplastic resin described below is contained, these substances may be incorporated into the thermoplastic resin in advance. Furthermore, these substances may be incorporated at any timing during the preparation of the thermoplastic starch composition of the present disclosure.

[0051] [Water contained in thermoplastic starch composition] As described above, it is preferable that the thermoplastic starch composition of the present disclosure is substantially free of water as the starch plasticizer. This is because, as described above, if water is substantially contained as the starch plasticizer, when the water-containing thermoplastic starch composition is kneaded (heated), the water contained as the starch plasticizer is likely to be discharged outside the system. As a result, the starch plasticizer component contained in the thermoplastic starch composition before forming into strands may decrease in volume compared to before the kneading, causing the thermoplasticity of the starch to be lost and resulting in a significant decrease in the dispersibility of the starch in the thermoplastic starch composition.

[0052] On the other hand, when the content of the starch plasticizer satisfies the aforementioned numerical range (hereinafter, sometimes simply referred to as "when a sufficient amount of starch plasticizer is contained"), the thermoplastic starch composition of the present disclosure may contain a small amount of water. When the thermoplastic starch composition of the present disclosure contains a sufficient amount of starch plasticizer, it is preferable to contain a small amount of water (i.e., a water content greater than 0% by mass) because this facilitates plasticization of the thermoplastic starch composition and facilitates optimization of the production conditions for the thermoplastic starch composition. When the thermoplastic starch composition of the present disclosure contains a sufficient amount of starch plasticizer, the water content of all raw materials constituting the thermoplastic starch composition of the present disclosure (hereinafter, sometimes simply referred to as "total water content of raw materials") is, for example, greater than 0% by mass and 30% by mass or less, preferably 5 to 30% by mass, more preferably 6 to 25% by mass, even more preferably 7 to 22% by mass, and most preferably 8 to 20% by mass, based on the total weight of all components other than water contained in the thermoplastic starch composition as 100% by mass, taking into account the plasticity of the starch. The total moisture content of the raw materials in the present disclosure may be calculated, for example, from the ratio of the weight of water added to the thermoplastic starch composition and the moisture content of all components other than water contained in the thermoplastic starch composition to the total weight of the thermoplastic starch composition. Furthermore, the total moisture content of the raw materials in the present disclosure may be calculated, for example, from the change in weight of the thermoplastic starch composition before and after drying using a dryer or the like, or may be measured using a device such as a moisture meter.

[0053] The thermoplastic starch composition provided in the present disclosure is not limited in its final form, and may be in the form of, for example, pellets or flakes, which will be described later, a compound obtained by further mixing the pellets or flakes with a thermoplastic resin, a resin molded product obtained by further mixing the compound with another thermoplastic resin, or a resin molded product, which will be described later, obtained by molding any of these.

[0054] <Pellets, flakes, compounds, and resin molded products> Next, the pellets, flakes, compound bodies, and resin molded products of the present disclosure will be described.

[0055] As described above, the pellets and flakes of the present disclosure comprise the thermoplastic starch composition of the present disclosure. In the present disclosure, the term "pellets" refers to, for example, the thermoplastic starch composition molded into a granular shape or the like, and more specifically, refers to a molded product obtained by cutting the thermoplastic starch composition in the form of strands. Furthermore, the term "pellet-like" refers to the shape or form of the product obtained when the thermoplastic starch composition in the form of strands is cut into granular shapes or the like. In the present disclosure, the term "flakes" refers to, for example, the thermoplastic starch composition molded into a plate, cube, rectangular parallelepiped, polygonal prism, polygonal pyramid, or the like, and more specifically, refers to the shape or form of the product obtained when the thermoplastic starch composition in the form of strands is cut. Furthermore, the term "flake-like" refers to the shape or form of the product obtained when the thermoplastic starch composition in the form of strands is cut into a plate, cube, rectangular parallelepiped, polygonal prism, polygonal pyramid, or the like.

[0056] As described above, the compound body of the present disclosure contains the thermoplastic starch composition of the present disclosure and another thermoplastic resin. The other thermoplastic resin is not particularly limited, and may be, for example, the same as the thermoplastic resin described above for the thermoplastic starch composition of the present disclosure. The compound body of the present disclosure may be extrusion-molded and then molded again into pellets, flakes, sheets, or the like. The compound body molded into pellets, flakes, or the like can be molded into a resin molded product, similar to the pellets and flakes of the present disclosure containing the thermoplastic starch composition of the present disclosure.

[0057] <Method for producing thermoplastic starch composition, method for producing pellets, flakes, etc., and method for producing compound body>

[0058] [Method for producing thermoplastic starch composition] As described above, the method for producing a thermoplastic starch composition of the present disclosure includes a mixing step of mixing raw materials containing the starch and the starch plasticizer. The starch may be, for example, the low-molecular-weight starch. The raw materials may further include, for example, the metal halide salt. The raw materials may also include, for example, the other additives used in the thermoplastic starch composition of the present disclosure.

[0059] The mixing step will be specifically described using an example. In the mixing step, for example, the starch and the starch plasticizer are kneaded while being heated. By this kneading, the thermoplastic starch composition of the present disclosure is obtained. Examples of equipment for the kneading include a mill, a despa, a mixer kneader, a Banbury mixer, a roll, a single-screw or multi-screw extruder having two or more screws, and a continuous kneader. Furthermore, a combination of these kneaders may be used, for example, a 1.5-screw extruder that combines a single-screw and a twin-screw extruder. In the present disclosure, there are no particular limitations, but for example, from the viewpoint of production speed, a multi-screw extruder or a combination thereof is preferred, and a twin-screw extruder is more preferred.

[0060] The pressure during the kneading is not particularly limited, but from the viewpoint of stable production, it is, for example, 0 MPa or more and 15 MPa or less, 10 MPa or less, 5 MPa or less, or 3 MPa or less, and the range is, for example, preferably 0 to 15 MPa, 0 to 10 MPa, or 0 to 5 MPa, and more preferably 0 to 3 MPa.

[0061] The temperature during the kneading is not particularly limited, but is, for example, 80°C or higher, 90°C or higher, or 100°C or higher from the viewpoint of sufficiently plasticizing the starch, and is 300°C or lower, 250°C or lower, 200°C or lower, 150°C or lower, or 130°C or lower from the viewpoint of preventing carbonization of the starch, and the range is, for example, 80 to 300°C, 90 to 200°C, or 100 to 130°C.

[0062] In the mixing step, the order of mixing is not particularly limited as long as the starch is plasticized and the thermoplastic starch composition of the present disclosure is obtained. For example, when the metal halide salt is contained, the starch, the starch plasticizer, and the metal halide salt may all be introduced into the kneading equipment at the same time, or the starch and the metal halide salt may be mixed first, and then the starch plasticizer may be added and introduced into the kneading equipment.

[0063] The method for mixing the metal halide salt with the starch is not particularly limited. For example, the metal halide salt may be mixed with the starch in advance, or may be mixed simultaneously with the starch plasticizer. The metal halide salt may also be added from a separate raw material inlet from the starch inlet using an extruder or the like. From the viewpoint of dispersibility in the raw materials contained in the thermoplastic starch composition, the metal halide salt is preferably mixed simultaneously with the starch plasticizer, and more preferably mixed in advance.

[0064] The metal halide salt may be mixed as a solid such as a powder, or as a liquid such as an aqueous solution, although mixing as a liquid is preferred from the viewpoint of dispersion.

[0065] When a low-molecular-weight starch is used as the starch, the method for producing a thermoplastic starch composition according to the present disclosure may further include, for example, a low-molecular-weight step of subjecting the starch to a low-molecular-weight treatment to obtain a low-molecular-weight starch. The low-molecular-weight step may be carried out, for example, within an extruder system for extruding the thermoplastic starch composition according to the present disclosure. When the low-molecular-weight step is carried out within the extruder system, it is preferable that, among the starch treatment methods described above, the treatment method does not damage the extruder.

[0066] [Manufacturing methods for pellets, flakes, etc.] After the kneading, the thermoplastic starch composition may be extruded from a heated extrusion port and molded into an appropriate shape. The shape of the molded product is not particularly limited, and examples thereof include pellets, flakes, crumbs, powder, sheets, and chips. After the kneading, the product may be molded directly into a molded product. In this specification, molded products in the form of pellets, flakes, or sheets may be simply referred to as "pellets," "flakes," or "sheets."

[0067] When forming the starch into pellets or flakes, the pellets or flakes of the present disclosure can be produced, for example, as follows: As described above, the method for producing the pellets or flakes of the present disclosure includes a strand forming step of extruding the thermoplastic starch composition of the present disclosure to form strands, and a strand cutting step of cutting the strands to form pellets or flakes.

[0068] The strand formation step includes, for example, a step of extruding the thermoplastic starch composition mixed in the mixing step (extrusion step). The extrusion step can be carried out, for example, using a conventionally known extruder. The extruder is not particularly limited, but for example, a twin-screw extruder can be used. Both the mixing step and the extrusion step may be carried out using an extruder. The composition obtained in the mixing step may be recovered and supplied to the extruder in the extrusion step to form strands.

[0069] The strand cutting step is, for example, a step of cutting the thermoplastic starch composition in the form of strands discharged from an extrusion outlet in the extrusion step. Methods for converting the thermoplastic starch composition in the form of strands into pellets or flakes include, for example, a cold cut method in which the strands are air- or water-cooled and then cut with a strand cutter, a hot cut method in which the strands are cut with a rotary cutter attached to the outlet of the extruder, and an underwater cut method. From the viewpoint of quality stability, for example, the cold cut method and the hot cut method are preferred, and the cold cut method is more preferred.

[0070] [Manufacturing method of compound body] As described above, the method for producing the compound body of the present disclosure includes a first kneading step of kneading raw materials containing the pellets or flakes of the present disclosure with the thermoplastic resin. The raw materials may also contain, for example, other thermoplastic resins, the other additives, etc.

[0071] [Method of manufacturing resin molded products] As described above, the method for producing a resin molded product according to the present disclosure includes a resin molding step of producing a resin molded product by resin molding a raw material containing the compound body according to the present disclosure. The resin molding step may include, for example, a second kneading step of kneading the compound body according to the present disclosure with a raw material containing another thermoplastic resin, and a resin molding step of resin molding the kneaded material obtained in the second kneading step.

[0072] The resin molding step may be, for example, a step of resin molding the compound obtained in the first kneading step to produce a resin molded product. The resin molding step can be performed by, for example, a conventionally known method. Examples of such methods include calendar molding, thermoforming, extrusion blow molding, inflation molding, vacuum molding, cast molding, foam molding, extrusion molding, injection molding, press molding, and melt spinning. Examples of molded products include containers, packaging materials, cushioning materials, daily necessities, machine parts, building materials, and automobile parts. [Example]

[0073] Next, examples of the present disclosure will be described, but the present disclosure is not limited to the following examples.

[0074] In this example and the above-described embodiment, the viscosity, melt flow rate (MFR), and elongation at break of the thermoplastic starch composition were measured by the following procedures.

[0075] [Viscosity measurement] 75 g of the thermoplastic starch composition and 425 g of water were weighed into a stainless steel container and heated to 95°C in a water bath while stirring at 400 rpm. After heating, the container was held for 20 minutes and then, without cooling, stirred at 15,000 rpm for 1 minute using a homogenizer (Microtec Nichion Co., Ltd., trade name: Hiscotron NS-50S). The resulting paste was transferred to a 300 ml tall beaker and cooled to 70°C. The B-type viscosity was measured using a B-type viscometer (Toki Sangyo Co., Ltd., trade name: TVB10M). The viscosity X was calculated from the measured B-type viscosity using the aforementioned formula (1).

[0076] [MFR measurement] The MFR was measured in accordance with JIS K 7210 using a melt indexer (Toyo Seiki Co., Ltd., product name: G-02) at a temperature of 160°C under a load of 5 kg. The measurement sample was prepared by weighing 30 g of a thermoplastic starch composition in pellet form onto an aluminum tray, spreading the pellets so that they did not overlap, heating them at 160°C for 30 minutes, and then allowing them to cool at room temperature for 6 hours. The heat treatment was carried out using a shelf-type air-blowing dryer (Advantec Toyo Co., Ltd., product name: DRK632DC).

[0077] [Breaking elongation] The compound obtained by the method described below was sandwiched between PET films and molded in a heat press (AS ONE Corporation, product name: H300-1) at 150°C and 0.8 t for 6 minutes. The PET films were then removed and cooled to room temperature to produce films with thicknesses of 0.1 to 1.5 mm. The resulting films were then left to stand at 23°C and 50% RH for 1 week and then molded into dumbbell test specimens (JIS K 7127 Type 5) using a lever-type specimen cutter (Dumbell Corporation, model number: SDL-100). Nine dumbbell test specimens were measured at 23°C and 50% RH using a universal testing machine (A&D Corporation, model number: RTG-1210) with a chuck distance of 70 mm and a pulling speed of 100 mm / min to determine the tensile elongation at break (elongation at break). The elongation at break was calculated as the average of the seven samples, excluding the maximum and minimum values ​​from the nine samples. Unless otherwise specified, the breaking elongation (% GL) defined in this specification is the result obtained by the above method. The result obtained by the above method is also defined as the characteristic of the thermoplastic starch composition in this example.

[0078] <Production of Thermoplastic Starch Composition> (Materials used) The starches used in this example were "unprocessed cornstarch (Nihon Shokuhin Kako Co., Ltd., product name: Nisshoku Cornstarch Y (moisture content: 13.2%))", "oxidized starch (Nihon Shokuhin Kako Co., Ltd., product name: MS#3800 (moisture content: 13.9%))", acid-treated starch, and metal halide salt-treated starch.

[0079] Glycerol (Kanto Chemical Co., Ltd.) and sorbitol (Kanto Chemical Co., Ltd.) were used as starch plasticizers.

[0080] The metal halide salts used were magnesium chloride hexahydrate (Kanto Chemical Co., Ltd., special grade), calcium chloride (Kanto Chemical Co., Ltd., special grade), and magnesium bromide hexahydrate (Fujifilm Wako Pure Chemical Industries, Ltd.).

[0081] (Preparation of acid-treated starch) First, the temperature of a starch (unmodified cornstarch) slurry was adjusted to 40°C to 50°C, and 4% by weight of hydrochloric acid relative to the starch was added. Five hours after the addition of the hydrochloric acid, 4% by weight of sodium hydroxide was added until the pH reached 7. The mixture was then dehydrated, washed with water in an amount five times the weight of the starch, and dehydrated twice. Next, the wet cake was loosened and dried overnight at 40°C to obtain an acid-treated starch.

[0082] (Preparation of metal halide salt-treated starch) First, 1% by weight of a metal halide salt relative to the weight of starch was dissolved in 20% by weight of water relative to the weight of starch. Next, the dissolved material was mixed with starch (unmodified cornstarch), reacted at 130°C, and allowed to cool to room temperature to obtain a metal halide salt-treated starch. When calcium chloride was used, the reaction time was 3 hours, and when magnesium chloride was used, the reaction time was 1 hour. The metal halide salt-treated starch was washed with water in an amount 5 times the weight of the starch and dehydrated twice to remove salt from the starch.

[0083] The starch content listed in the table includes the water content of the starch. In addition, in the examples, "cornstarch" may be simply referred to as "cornstarch."

[0084] [Example 1, Comparative Example 1] Pellets containing the thermoplastic starch compositions of the present examples and comparative examples were prepared by the following procedure.

[0085] (Production of pellets containing thermoplastic starch composition) The raw materials listed in Table 1 below were premixed in a Kenwood mixer. The resulting mixture was fed from a feeder installed above C1 (the inlet of the kneader) of a twin-screw extruder (φ20 mm, L / D=45, Technobel Corporation). While pellets were produced using a twin-screw extruder in this example, other pellet-producing devices are possible. The kneading temperature was adjusted so that the outlet temperature (the temperature of the thermoplastic starch composition at the outlet of the kneader) was 128°C, and the shaft rotation speed was set to 100 rpm. The discharged strands were air-cooled on a belt conveyor (Shinsei Sangyo Co., Ltd., Model: SMB-100) and fed to the inlet of a pelletizer (Technobel Corporation, Product Name: SCP-203-2MT). The strands pulled by the pelletizer were cut in the pelletizer to produce pellets containing the thermoplastic starch compositions of Example 1 and Comparative Example 1 listed in Table 1 below (Test Groups A-1 to A-10 and X-1 to X-3).

[0086] [Table 1-1]

[0087] [Table 1-2]

[0088] [Example 2, Comparative Example 2] The compound bodies of the present example and comparative example were prepared according to the following procedure.

[0089] (Production of Compound Body Containing Thermoplastic Starch Composition) As shown in Table 2 below, the thermoplastic starch compositions prepared in Example 1 and Comparative Example 1, a thermoplastic resin (LDPE, Tosoh Corporation, trade name: Petrothene® LDPE183, MFR 2 g / 10 min (according to JIS K 6922-1), elongation at break 400.3% GL), and a compatibilizer (Mitsui Chemicals, Inc., trade name: Admer HE-810) were placed in a polyethylene bag, the bag's opening was tied, and the mixture was thoroughly mixed by shaking up and down and left and right. The entire mixture was fed from a feeder installed above C1 of a twin-screw extruder (φ20 mm, L / D=45, Technovel Corporation). The kneading temperature was adjusted so that the product temperature at the outlet was 159°C, and the shaft rotation speed was set to 150 rpm. The discharged strand compound was held by hand, water-cooled in a water tank (Technovel Co., Ltd., product name: SCB150-1500), and fed to the inlet of a pelletizer (Technovel Co., Ltd., product name: SCP-203-2MT). The strand pulled by the pelletizer was cut inside the pelletizer to produce a pellet-shaped compound. The breaking elongation (%GL) of the obtained compound was measured.

[0090] [Table 2-1]

[0091] [Table 2-2]

[0092] [Table 2-3]

[0093] [Example 3, Comparative Example 3] In the present examples and comparative examples, compound bodies were prepared using thermoplastic resins with different fluidities.

[0094] The compounds of Example 3 and Comparative Example 3 were produced in the same manner as in Example 2, except that the thermoplastic resin was changed to a thermoplastic resin with different fluidity as shown in Table 3 below (LDPE, Tosoh Corporation, trade name: Petrothene (registered trademark) LDPE212, MFR 13 g / 10 min (according to JIS K 6922-1), elongation at break 317.3% GL; LDPE, Tosoh Corporation, trade name: Petrothene (registered trademark) LDPE249, MFR 70 g / 10 min (according to JIS K 6922-1), elongation at break 287.5% GL).

[0095] [Table 3-1]

[0096] [Table 3-2]

[0097] [Example 4, Comparative Example 4] In the present examples and comparative examples, the type of thermoplastic resin was changed to polypropylene (PP) to prepare the compound body.

[0098] The compound bodies of Example 4 and Comparative Example 4 were produced in the same manner as in Example 2, except that the thermoplastic resin was changed to the thermoplastic resin shown in Table 4 below (PP, SunAllomer Co., Ltd., product name: PF621S, MFR 6.5 g / 10 min (according to JIS K 6921-2), elongation at break 584.4% GL), and the set temperature of each die of the twin-screw extruder was adjusted so that the product temperature at the outlet was 180°C.

[0099] [Table 4]

[0100] [Example 5, Comparative Example 5] In the present examples and comparative examples, the compound bodies were prepared by changing the type of thermoplastic resin.

[0101] The compounds of Example 5 and Comparative Example 5 were produced in the same manner as in Example 2, except that the thermoplastic resin was changed to the thermoplastic resin shown in Table 5 below (PBS, Mitsubishi Chemical Corporation, product name: FZ91, MFR 5 g / 10 min (according to ISO 1133), elongation at break 52.9% GL).

[0102] [Table 5]

[0103] [Example 6, Comparative Example 6] In the present examples and comparative examples, compound bodies were prepared by changing the blending ratio of the thermoplastic resin.

[0104] Compound bodies of Example 6 and Comparative Example 6 were produced in the same manner as in Example 2, except that the blending ratios of the thermoplastic starch composition and the thermoplastic resin were changed as shown in Table 6 below.

[0105] [Table 6]

[0106] As shown in Table 1, the thermoplastic starch composition of Example 1 containing a metal halide salt and the thermoplastic starch composition prepared using starch that had been previously subjected to a low-molecular-weight treatment all had lower viscosities than the test plots X-1 to X-3 containing cornstarch, an unmodified starch, and fluidity was also observed in the MFR measurement. Test plots A-9 and X-2 had a reduced starch content and an increased glycerol content, but even under these conditions, the addition of a metal halide salt resulted in a lower viscosity, and fluidity was also observed in the MFR. Fluidity was also observed in A-10, which had an increased starch content and a decreased glycerol content.

[0107] As shown in Table 2, the test plots of the Examples showed higher breaking elongation than the Comparative Examples under conditions where the thermoplastic starch compositions containing glycerol or sorbitol as a starch plasticizer and LDPE183 were blended as a thermoplastic resin. That is, the Examples showed less change in breaking elongation from the raw material LDPE183 compared to the Comparative Examples. The above-mentioned tendency was the same regardless of whether a compatibilizer was blended or not.

[0108] As shown in Table 3, even when the thermoplastic resin was changed to another PE with different fluidity, the elongation at break of the examples (test plots B2-1 to B2-6) was superior to that of the comparative examples (test plots B2X-1 to B2X-4).

[0109] As shown in Table 4, even when the thermoplastic resin was changed to PP, the elongation at break of the examples (test plots B3-1 and B3-2) was superior to that of the comparative example (test plot B3X-1).

[0110] As shown in Table 5, even when the thermoplastic resin was changed to PBS, the breaking elongation of the example (test plot B4-1) was superior to that of the comparative example (test plot B4X-1).

[0111] As shown in Table 6, even when the thermoplastic starch composition was highly blended, the breaking elongation of the Examples (Test plots B5-1 and B5-2) was superior to that of the Comparative Examples (Test plots B1X-1A and B5X-1).

[0112] <Additional Notes> Some or all of the above embodiments and examples may be described as, but are not limited to, the following supplementary notes. (Appendix 1) 1. A thermoplastic starch composition comprising: starch and a plasticizer for starch, The thermoplastic starch composition diluted with water to 15% by weight is heated to 95°C in a water bath, heated and stirred at 400 rpm for 20 minutes, dispersed at 15,000 rpm for 1 minute using a homogenizer, and cooled to 70°C in a water bath, and the viscosity measured with a B-type viscometer is 270 mPa s or less. Thermoplastic starch composition. (Appendix 2) The viscosity X calculated by the following formula (1) is 270 mPa s or less. 2. The thermoplastic starch composition of claim 1. X=A+(73-B)×6.57 (1) In the formula (1), A is the viscosity measured using a B-type viscometer after adding the thermoplastic starch composition to water so that the concentration becomes 15% by weight, heating the mixture to 95°C in a water bath, heating and stirring the mixture at 400 rpm for 20 minutes, dispersing the mixture at 15,000 rpm for 1 minute using a homogenizer, and cooling the mixture to 70°C in a water bath; B is the content of the starch when the total weight of all components other than water contained in the thermoplastic starch composition is taken as 100% by weight. (Appendix 3) The total weight of all components other than water contained in the thermoplastic starch composition is taken as 100% by weight, The starch content is 60 to 95% by weight, The content of the starch plasticizer is 5 to 35% by weight. 3. The thermoplastic starch composition according to claim 1 or 2. (Appendix 4) 1. A thermoplastic starch composition comprising: starch and a plasticizer for starch, The total weight of all components other than water contained in the thermoplastic starch composition is taken as 100% by weight, The starch content is 60 to 95% by weight, The content of the starch plasticizer is 5 to 35% by weight, The thermoplastic starch composition has a melt flow rate of 0.01 g / 10 min or more at a temperature of 160°C under a load of 5 kg according to JIS K 7210. Thermoplastic starch composition. (Appendix 5) The starch includes a low molecular weight starch, The depolymerized starch is a washed depolymerized starch. 5. The thermoplastic starch composition of any one of claims 1 to 4. (Appendix 6) 6. The thermoplastic starch composition according to claim 5, wherein the low molecular weight starch is a metal halide salt-treated starch that has been subjected to a low molecular weight treatment with a metal halide salt. (Appendix 7) 7. The thermoplastic starch composition according to any one of claims 1 to 6, wherein the starch plasticizer comprises at least one of a polyhydric alcohol and a sugar. (Appendix 8) the polyhydric alcohol is at least one selected from the group consisting of glycerin, propylene glycol, and ethylene glycol; The sugar is at least one of sorbitol and glucose. 8. The thermoplastic starch composition of claim 7. (Appendix 9) Further, it contains a metal halide salt, The total weight of all components other than water contained in the thermoplastic starch composition is taken as 100% by weight, The content of the metal halide salt is 0.1 to 10% by weight. 9. The thermoplastic starch composition of any of claims 1 to 8. (Appendix 10) 10. The thermoplastic starch composition according to any one of claims 1 to 9, wherein the starch plasticizer is substantially free of water. (Appendix 11) 11. A pellet comprising the thermoplastic starch composition of any of claims 1 to 10. (Appendix 12) 11. A flake comprising the thermoplastic starch composition of any of claims 1 to 10. (Appendix 13) 11. A compound body comprising the thermoplastic starch composition of any one of claims 1 to 10. (Appendix 14) A molded resin article comprising the thermoplastic starch composition according to any one of claims 1 to 10. (Appendix 15) a mixing step of mixing raw materials containing the starch and the starch plasticizer, 11. A method for producing a thermoplastic starch composition according to any one of claims 1 to 10. (Appendix 16) Further, the method includes a step of subjecting the starch to a low molecular weight treatment to obtain a low molecular weight starch, the mixing step is a step of mixing raw materials containing the low-molecular-weight starch and the starch plasticizer; The manufacturing method according to claim 15. (Appendix 17) 17. The manufacturing method according to claim 16, wherein the molecular weight reduction step is carried out in an extruder system for extruding the thermoplastic starch composition. (Appendix 18) a strand forming step of extruding the thermoplastic starch composition to form strands; and a strand cutting step of cutting the strands to form pellets or flakes, 11. A method for producing pellets or flakes, wherein the thermoplastic starch composition is the thermoplastic starch composition of any one of appendixes 1 to 10. (Appendix 19) A first kneading step of kneading a raw material containing pellets and a raw material containing a thermoplastic resin, 12. The method for producing a compound body, wherein the pellets are the pellets described in Appendix 11. (Appendix 20) A first kneading step of kneading a raw material containing flakes and a raw material containing a thermoplastic resin, The method for producing a compound body, wherein the flakes are the flakes described in Appendix 12. (Appendix 21) A resin molding step of resin-molding a raw material including a compound body to produce a resin molded product, 14. A method for producing a resin molded product, wherein the compound body is the compound body described in Appendix 13. (Appendix 22) a second kneading step of kneading the compound body with a raw material containing another thermoplastic resin; A resin molding step of resin-molding the kneaded product obtained in the second kneading step to produce a resin molded product, 22. A method for producing a resin molded product according to claim 21. [Industrial Applicability]

[0113] As described above, the present disclosure can provide a thermoplastic starch composition, pellets, flakes, compound body, resin molded product, a method for producing a thermoplastic starch composition, a method for producing pellets or flakes, a method for producing a compound body, and a method for producing a resin molded product, having fluidity. The present disclosure can provide, for example, a thermoplastic starch composition and a masterbatch of a thermoplastic starch composition, having fluidity. Furthermore, for example, by kneading the thermoplastic starch composition of the present disclosure with a thermoplastic resin, a compound body with a high starch content can be efficiently mass-produced. For example, by providing a thermoplastic starch composition with high fluidity, i.e., a low B-type viscosity, a compound body exhibiting excellent physical properties different from those of blends with conventional thermoplastic starch compositions with high B-type viscosity can be provided, such as a compound body exhibiting a high breaking elongation value. For example, by providing a thermoplastic starch composition with high fluidity, i.e., a high MFR, a compound body exhibiting excellent physical properties different from those of blends with conventional thermoplastic starch compositions with low MFR can be provided, such as a compound body exhibiting a high breaking elongation value. The applications of the present disclosure are not particularly limited. For example, the applications of the thermoplastic starch composition of the present disclosure are not limited to the pellets, flakes, and resin molded products of the present disclosure, and are optional and can be used in a wide range of applications.

Claims

1. 1. A thermoplastic starch composition comprising: starch and a plasticizer for starch, The thermoplastic starch composition diluted with water to 15% by weight is heated to 95°C in a water bath, heated and stirred at 400 rpm for 20 minutes, dispersed at 15,000 rpm for 1 minute using a homogenizer, and cooled to 70°C in a water bath, and the viscosity measured with a Brookfield viscometer is 270 mPa s or less. Thermoplastic starch composition.

2. The viscosity X calculated by the following formula (1) is 270 mPa s or less. The thermoplastic starch composition of claim 1. X=A+(73-B)×6.57 (1) In the formula (1), A is the viscosity measured by a Brookfield viscometer after adding the thermoplastic starch composition to water so that the concentration becomes 15% by weight, heating the mixture to 95°C in a water bath, stirring the mixture for 20 minutes at 400 rpm, dispersing the mixture at 15,000 rpm for 1 minute using a homogenizer, and cooling the mixture to 70°C in a water bath; B is the content of the starch when the total weight of all components other than water contained in the thermoplastic starch composition is taken as 100% by weight.

3. The total weight of all components other than water contained in the thermoplastic starch composition is taken as 100% by weight, The starch content is 60 to 95% by weight, The content of the starch plasticizer is 5 to 35% by weight. The thermoplastic starch composition of claim 1.

4. 1. A thermoplastic starch composition comprising: starch and a plasticizer for starch, The total weight of all components other than water contained in the thermoplastic starch composition is taken as 100% by weight, The starch content is 60 to 95% by weight, The content of the starch plasticizer is 5 to 35% by weight, The thermoplastic starch composition has a melt flow rate of 0.01 g / 10 min or more at a temperature of 160°C under a load of 5 kg according to JIS K 7210. Thermoplastic starch composition.

5. The starch includes a low molecular weight starch, The depolymerized starch is a washed depolymerized starch.

5. The thermoplastic starch composition of claim 1.

6. 6. The thermoplastic starch composition according to claim 5, wherein the low molecular weight starch is a metal halide salt-treated starch that has been subjected to a low molecular weight treatment with a metal halide salt.

7. The thermoplastic starch composition according to claim 1 , wherein the starch plasticizer comprises at least one of a polyhydric alcohol and a sugar.

8. the polyhydric alcohol is at least one selected from the group consisting of glycerin, propylene glycol, and ethylene glycol; The sugar is at least one of sorbitol and glucose. The thermoplastic starch composition of claim 7.

9. Further, it contains a metal halide salt, The total weight of all components other than water contained in the thermoplastic starch composition is taken as 100% by weight, The content of the metal halide salt is 0.1 to 10% by weight.

5. The thermoplastic starch composition of claim 1.

10. 5. The thermoplastic starch composition according to claim 1, which is substantially free of water as a plasticizer for the starch.

11. A pellet comprising the thermoplastic starch composition of any one of claims 1 to 4.

12. A flake comprising the thermoplastic starch composition of any one of claims 1 to 4.

13. A compound body comprising the thermoplastic starch composition of any one of claims 1 to 4.

14. A resin molded article comprising the thermoplastic starch composition according to any one of claims 1 to 4.

15. a mixing step of mixing raw materials containing the starch and the starch plasticizer, A method for producing the thermoplastic starch composition of any one of claims 1 to 4.

16. Further, the method includes a step of subjecting the starch to a low molecular weight treatment to obtain a low molecular weight starch, the mixing step is a step of mixing raw materials containing the low-molecular-weight starch and the starch plasticizer; The method of claim 15.

17. The method according to claim 16, wherein the step of depolymerizing is carried out in an extruder system for extruding the thermoplastic starch composition.

18. a strand forming step of extruding the thermoplastic starch composition to form strands; and a strand cutting step of cutting the strands to form pellets or flakes, The method for producing pellets or flakes, wherein the thermoplastic starch composition is the thermoplastic starch composition of any one of claims 1 to 4.

19. A first kneading step of kneading a raw material containing pellets and a raw material containing a thermoplastic resin, The method for producing a compound body, wherein the pellet is the pellet according to claim 11.

20. A first kneading step of kneading a raw material containing flakes and a raw material containing a thermoplastic resin, The method for producing a compound body, wherein the flakes are the flakes according to claim 12.

21. A resin molding step of resin-molding a raw material including a compound body to produce a resin molded product, The method for producing a resin molded product, wherein the compound body is the compound body according to claim 13.

22. a second kneading step of kneading the compound body with raw materials containing other thermoplastic resins; A resin molding step of resin-molding the kneaded product obtained in the second kneading step to produce a resin molded product, A method for producing the resin molded product according to claim 21.

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