Thermoplastic starch composition containing starch and a starch plasticizer, 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 a thermoplastic starch composition, pellets, flakes, a compound, 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, and a method for producing a resin molded product.

Background Art

[0002] Recently, from the viewpoints of utilization of renewable materials and reduction of carbon dioxide emissions, i.e., carbon circulation, and environmental protection of the earth by the spread of biodegradable resins, a switch from conventional petroleum-derived resins to biomass-derived resins has been demanded. Under such circumstances, Patent Document 1 discloses a method of blending starch with a resin.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, as disclosed in Patent Document 1, a composition simply mixed with starch and a plasticizer for starch may have significantly low fluidity. A composition with low fluidity is difficult to disperse in a thermoplastic resin, which may cause deterioration of the physical properties of a resin molded product. A resin molded product produced using such a compound or composition has limited physical properties and quality, and thus inevitably has limited uses.

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

Means for Solving the Problems

[0006] To achieve the aforementioned objective, one aspect of the thermoplastic starch composition of this disclosure is: A thermoplastic starch composition, Contains starch and a plasticizer for starch, The thermoplastic starch composition, diluted to 15% by weight with water, is heated to 95°C in a water bath, stirred at 400 rpm for 20 minutes, dispersed using a homogenizer at 15000 rpm for 1 minute, cooled to 70°C in a water bath, and the viscosity measured by a B-type viscometer is 270 mPa·s or less.

[0007] One embodiment of the thermoplastic starch composition of this disclosure is Contains 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 60-95% by weight. The content of the aforementioned starch plasticizer is 5 to 35% by weight. The melt flow rate of the thermoplastic starch composition at a temperature of 160°C and a load of 5 kg, in accordance with JIS K 7210, is 0.01 g / 10 min or more.

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

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

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

[0011] The resin molded articles of this disclosure include the thermoplastic starch composition of this disclosure.

[0012] The method for producing the thermoplastic starch composition of this disclosure is as follows: The process includes a mixing step of mixing the raw materials, which include the starch and the plasticizer for the starch.

[0013] The method for producing pellets or flakes as disclosed herein is: A strand forming step of extruding a thermoplastic starch composition to form strands, and a strand cutting step of cutting the strands to form pellets or flakes, wherein the thermoplastic starch composition is the thermoplastic starch composition of the present disclosure.

[0014] The method for producing a compound body of the present disclosure includes a first kneading step of kneading a raw material containing pellets or flakes and a raw material containing a thermoplastic resin, wherein the pellets are the pellets of the present disclosure, and the flakes are the flakes of the present disclosure.

[0015] The method for producing a resin molded product of the present disclosure includes a resin molding step of resin molding a raw material containing a compound body to produce a resin molded product, wherein the compound body is the compound body of the present disclosure.

Advantages of the Invention

[0016] According to the present disclosure, a thermoplastic starch composition having fluidity can be obtained.

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments suitable for the implementation of the present disclosure will be disclosed. However, the following embodiments disclose typical embodiments of the present disclosure, and the scope of the present disclosure is not limited to only these embodiments.

[0018] In the present disclosure, unless otherwise specified, "mass %" and "weight %" 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" generally refers to a thermoplastic starch composition discharged from various extruders, and the shape such as the length is not particularly limited. For example, it includes any shape as long as it is discharged from various extruders, such as a long string-like one or a short flat plate-like one.

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

[0021] [Viscosity] In one aspect of the present disclosure, the thermoplastic starch composition diluted to 15% by weight with water is heated to 95°C in a water bath, heated and stirred at 400 rpm for 20 minutes, dispersed at 15000 rpm for 1 minute using a homogenizer, cooled to 70°C in the water bath, and then the viscosity measured by a B-type viscometer (hereinafter, may be simply referred to as "B-type viscosity") is 270 mPa·s or less. The upper limit value of the B-type 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 value 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 B-type viscosity can be measured by the measurement method described in the examples below. The B-type viscosity can be adjusted, for example, by adjusting the mixing ratio of starch, compatibilizer, thermoplastic resin, starch plasticizer, or metal halide salt, etc., described below, or the manufacturing temperature during production, or the manufacturing conditions such as kneading time.

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

[0023] Furthermore, the thermoplastic starch composition of this 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 above formula (1), A is the viscosity (the B-type viscosity) obtained by adding the thermoplastic starch composition to water to a concentration of 15% by weight, heating it in a water bath to 95°C, stirring it at 400 rpm for 20 minutes, dispersing it using a homogenizer at 15000 rpm for 1 minute, cooling it in a water bath to 70°C, and then measuring it with a B-type viscometer. B is the starch content when the total weight of all components other than water contained in the thermoplastic starch composition is set to 100% by weight.

[0024] The viscosity X may, for example, have an upper limit of 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 a lower limit of 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 value of the B-type viscosity 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, this disclosure is useful when a compound body with a high starch content and a high elongation at break 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 elongation at break.

[0026] [Melt Flow Rate (MFR)] In one embodiment of this disclosure, the melt flow rate (MFR) of the thermoplastic starch composition at a temperature of 160°C and a load of 5 kg, in accordance with JIS K 7210, is 0.01 g / 10 min or more. 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 aforementioned MFR can be adjusted, for example, by adjusting the blending ratio of starch, compatibilizer, thermoplastic resin, starch plasticizer, or metal halide salt, as described later, or by adjusting manufacturing conditions such as manufacturing temperature or kneading time during manufacturing.

[0027] When the thermoplastic starch composition of this disclosure has an MFR of 0.01 g / 10 min or higher, a thermoplastic starch composition exhibiting high fluidity can be obtained. For example, this disclosure is useful when a compound body with a high starch content and a high elongation at break 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 reduced elongation at break.

[0028] [starch] Examples of the starch mentioned above include unprocessed starch obtained from corn, potatoes, sweet potatoes, 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. Processed starches, such as those obtained by etherification, esterification, or cross-linking, are also included. The starch may be used individually or in combination of two or more types. From the viewpoint of manufacturing cost, for example, unprocessed starches such as corn starch and tapioca starch are preferred, and corn starch is more preferred.

[0029] The moisture content of the starch used in this 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% by weight or more, more preferably 65% ​​by weight or more, and even more preferably 70% by weight or more, with the total weight of all components other than water in the thermoplastic starch composition being 100% by weight, taking into consideration the improvement of the biomass content. From the viewpoint of dispersing the starch when mixed with a thermoplastic resin, the starch content is 95% by weight or less, preferably 90% by weight or less, more preferably 80% by weight or less, and most preferably 75% by weight or less, with the total weight of all components other than water in the thermoplastic starch composition being 100% by weight, and the range is, for example, 60-95% by weight, more preferably 60-85% by weight, even more preferably 60-80% by weight, and most preferably 65-75% by weight. This disclosure shows that, for example, even when the starch content is high, such as 60% by weight or more, if the MFR is 0.01 g / 10 min or more, it exhibits high fluidity, making it easy to knead with thermoplastic resins and the like.

[0031] For example, low-molecular-weight starch may be used as the starch. By using the low-molecular-weight starch, the thermoplastic starch composition can be easily dispersed in the resin, and a resin molded product having the desired physical properties or quality can be obtained. The low-molecular-weight starch is, for example, starch that has been treated to reduce molecular weight by the treatment method described later.

[0032] The starch treatment method for producing the low molecular weight starch is not particularly limited, but examples include chemical low molecular weight treatments such as acid treatment, alkali treatment, oxidation treatment, radical treatment, enzyme treatment, and mixing treatment with a metal salt; and physical low molecular weight treatments that apply energy to the starch, such as heat treatment, radiation treatment, electron beam treatment, microwave treatment, ultrasonic treatment, high-frequency treatment, pressure treatment, milling treatment, powder impact 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 method is preferably one of the following, which can be implemented easily and inexpensively: acid treatment, alkali treatment, oxidation treatment, enzyme treatment, mixing treatment with a metal salt, heat treatment, pulverization treatment, and extrusion treatment. The above treatment method may be one of the treatment methods or two or more 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 treatment to reduce damage to the equipment used. In other words, it is preferable that the low-molecular-weight starch is washed low-molecular-weight starch. The washing method is, for example, washing with water. The number of washes is not particularly limited.

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

[0034] As the starch before the low-molecular-weight treatment, conventionally known starches can be used, for example, unmodified starches such as corn starch, glutinous corn starch, wheat starch, potato starch, tapioca starch, and sago starch. In addition, as the starch before the low-molecular-weight treatment, for example, chemically modified starches that have undergone esterification, etherification, crosslinking, etc., physically modified starches that have undergone granulation, moist heat treatment, hot water treatment, bleaching treatment, sterilization treatment, etc., and modified starches obtained by applying any two or more of the above treatments can be used.

[0035] [Plasticizer for starch] In this disclosure, "plasticizer for starch" means a plasticizer used to plasticize starch unless otherwise specified. In other words, it does not mean a plasticizer used by those skilled in the art to adjust the physical properties of thermoplastic resins in a form that does not contain starch.

[0036] The aforementioned plasticizer for starch is not particularly limited as long as it is a substance that substantially plasticizes the starch, excluding water, but examples include polyhydric alcohols, sugars, ammonias, ureas, ionic liquids, etc. Examples of 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, diglycerol, etc. Examples of sugars include sorbitol, glucose, maltitol, mannitol, erythritol, etc. These may be used individually or in combination of two or more. These substances may, for example, be pre-included in the starch. Furthermore, if a thermoplastic resin, as described later, is included, these substances may be pre-included in the thermoplastic resin. They may also be included at any point in obtaining the thermoplastic starch composition of this disclosure.

[0037] The starch plasticizer used in this disclosure is preferably glycerin, propylene glycol, or sorbitol, and more preferably glycerin, from the viewpoint of its effect in 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, based on the total weight of all components other than water contained in the thermoplastic starch composition being 100% by weight.

[0039] Furthermore, it is preferable that the starch plasticizer substantially contains no water. In other words, it is preferable that the starch plasticizer is, for example, a starch plasticizer that does not have water as its main component. This is because, for example, if water is used as the main component of the starch plasticizer, foaming due to the evaporation of water occurs during the production of the thermoplastic starch composition or during the molding process of the compound body described later. For example, when producing in an extruder, if the thermoplastic starch composition unintentionally foams at the discharge port of the extruder, it may lead to a decrease in productivity. In addition, during the normal production of the thermoplastic starch composition or the molding process of the compound body described later, high temperature conditions of 100°C or higher and removal of gas by vacuum degassing are involved, so there is a high possibility that plasticizers with low boiling points, such as water, will be discharged outside the system. As a result, the amount of starch plasticizer component contained in the thermoplastic starch composition before forming the strands decreases compared to before kneading, the thermoplasticity of the starch is lost, and the dispersibility of the starch in the thermoplastic starch composition may be significantly reduced.

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

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

[0042] The content of the thermoplastic resin is not particularly limited, but it is preferable to have a high content of the starch, for example, in view of improving the biomass content, and is 0% by weight. Also, when the thermoplastic resin is included, with the total weight of all components other than water in the thermoplastic starch composition being 100% by weight, for example, the lower limit is greater than 0% by weight, 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 this disclosure can be, for example, any known metal halide salt. The metal halide salt may include, for example, at least one selected from the group consisting of metal chloride salts, metal bromide salts, and metal iodide salts. The effect of imparting fluidity to the thermoplastic starch composition, as described later, depends, for example, on the amount of substance of the metal halide salt contained in the thermoplastic starch composition. The greater the amount of substance of the metal halide salt contained in the thermoplastic starch composition, the greater the effect of imparting fluidity. Therefore, the metal halide salt preferably includes, for example, at least one of a metal chloride salt and a metal bromide salt, which contains more molecules (i.e., has a smaller molar mass) even if they are the same weight of metal halide salts, and more preferably 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; for example, it may be a solid such as a powder, or a liquid such as an aqueous solution. From the viewpoint of dispersion in the starch raw material, a 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, for example, thermoplastic starch compositions 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). Therefore, it is presumed that they are difficult to disperse when kneaded with thermoplastic resins as described later, causing a decrease in the physical properties of the compound. On the other hand, the inventors of this 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 the structure of the starch. However, this is merely a hypothesis, and this disclosure is not limited thereto.

[0047] [Compatibilizer] The thermoplastic starch composition of this disclosure may or may not further contain a compatibilizer. The compatibilizer is not particularly limited, and for example, a commonly known compatibilizer can be used. For example, it may contain one or more compounds selected from the group consisting of compounds having acid anhydride groups such as maleic anhydride, succinic anhydride, and glutaric anhydride; compounds having carboxyl groups such as maleic acid, succinic acid, and glutaric acid; compounds having epoxy groups; compounds having imino groups; compounds having isocyanate groups; compounds having oxazoline groups; and silane coupling agents having reactive groups such as alkoxy groups. Acid anhydride groups, epoxy groups, imino groups, and isocyanate groups are functional groups that can react with hydroxyl groups, and compounds having such functional groups are preferred as compatibilizers in this disclosure. Examples of compounds that can be used as compatibilizers include polymer compounds having the above-mentioned functional groups such as polyolefin, acrylic, and styrene, and from the viewpoint of ensuring affinity with the resin to be blended, polyolefin polymer compounds having the above-mentioned functional groups are preferred.

[0048] Examples of the polyolefin polymer compounds 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, but ethylene polymers and propylene polymers are preferred. Specific examples of the polyolefin polymer compounds having the above-mentioned functional groups include, for example, maleic anhydride-modified polyolefins, and 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% by weight, where the total weight of all components other than water contained in the thermoplastic starch composition is 100% by weight. The content of the compatibilizer may have a lower limit of 0.1% by weight or more, 0.5% by weight or more, or 1% by weight or more, and an upper limit of 10% by weight or less, or 8% by weight or less, where the total weight of all components other than water contained in the thermoplastic starch composition is 100% by weight, and the range is, for example, preferably 0.1 to 10% by weight, more preferably 0.1 to 8% by weight, even more preferably 0.5 to 8% by weight, and most preferably 1 to 8% by weight.

[0050] [Other additives] The thermoplastic starch composition of this disclosure may or may not contain, for example, various conventionally known additives. Examples of such additives include emulsifiers, elastomers, inorganic fillers, heat stabilizers, lightfasteners, ultraviolet absorbers, and antistatic agents. These may be used individually or in combination of two or more. These substances may also be pre-contained in the starch, for example. Furthermore, if a thermoplastic resin, as described later, is included, these substances may be pre-contained in the thermoplastic resin. Moreover, they may be added at any time when obtaining the thermoplastic starch composition of this disclosure.

[0051] [Water contained in thermoplastic starch composition] As described above, in the thermoplastic starch composition of this disclosure, it is preferable that the starch plasticizer is substantially free of water. This is because, as described above, if the starch plasticizer substantially contains water, when the thermoplastic starch composition containing water is kneaded (heated), the water contained in the starch plasticizer is likely to be discharged from the system. As a result, the amount of starch plasticizer component contained in the thermoplastic starch composition before forming the strands decreases compared to before kneading, the thermoplasticity of the starch is lost, and the dispersibility of the starch in the thermoplastic starch composition may be significantly reduced.

[0052] On the other hand, when the content of the starch plasticizer satisfies the aforementioned numerical range (hereinafter sometimes simply referred to as "when the starch plasticizer is sufficiently contained"), the thermoplastic starch composition of this disclosure may contain a small amount of water. When the starch plasticizer is sufficiently contained, it is preferable that the thermoplastic starch composition of this disclosure contains a small amount of water (i.e., the water content exceeds 0% by mass) because plasticization of the thermoplastic starch composition proceeds more easily, and the manufacturing conditions of the thermoplastic starch composition can be easily optimized. When the starch plasticizer is sufficiently contained, the water content contained in all the raw materials constituting the thermoplastic starch composition of this disclosure (hereinafter sometimes simply referred to as "total water content of raw materials") is, for example, considering the plasticity of the starch, with the total weight of all components other than water contained in the thermoplastic starch composition being 100% by weight, it is greater than 0% by weight and 30% by weight or less, preferably 5 to 30% by weight, more preferably 6 to 25% by weight, even more preferably 7 to 22% by weight, and most preferably 8 to 20% by weight. The total moisture content of the raw materials in this disclosure may be calculated, for example, from the ratio of the total weight of the thermoplastic starch composition to the total weight of the thermoplastic starch composition, plus the sum of the moisture content of all components other than water contained in the thermoplastic starch composition. Alternatively, the total moisture content of the raw materials in this disclosure may be calculated, for example, from the weight change of the thermoplastic starch composition before and after drying using a dryer or the like, or it may be measured using a device such as a moisture meter.

[0053] The thermoplastic starch composition provided in this disclosure is not limited to any final form, but can take the form of, for example, pellets or flakes as described later, a compound obtained by further mixing the pellets or flakes with a thermoplastic resin, a resin molded article obtained by further mixing the compound with another thermoplastic resin, or a resin molded article as described later obtained by molding them.

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

[0055] The pellets and flakes of this disclosure include the thermoplastic starch composition of this disclosure, as described above. In this disclosure, pellets refer to, for example, the thermoplastic starch composition molded into a granular or other shape, and more specifically, a molded product obtained by cutting the stranded thermoplastic starch composition. Pellet-like refers to the shape or form of the product obtained when the stranded thermoplastic starch composition is cut into granular or other shapes. In this disclosure, flakes refer to, for example, the thermoplastic starch composition molded into a plate-like, cubic, rectangular parallelepiped, polygonal prism, and polygonal pyramidal shape, and more specifically, a molded product obtained by cutting the stranded thermoplastic starch composition. Flake-like refers to the shape or form of the product obtained when the stranded thermoplastic starch composition is cut into a plate-like, cubic, rectangular parallelepiped, polygonal prism, and polygonal pyramidal shape.

[0056] The compound of this disclosure comprises the thermoplastic starch composition of this disclosure and other thermoplastic resins, as described above. The other thermoplastic resins are not particularly limited, but may be, for example, the same as the thermoplastic resins described in the thermoplastic starch composition of this disclosure above. The compound of this disclosure may be extruded and then reshaped into pellets, flakes, sheets, etc. Compounds molded into pellets, flakes, etc., can be molded into resin molded articles, similar to the pellets and flakes of this disclosure containing the thermoplastic starch composition of this disclosure.

[0057] <Methods for producing thermoplastic starch compositions, pellets, flakes, etc., and compound products>

[0058] [Method for producing thermoplastic starch composition] The method for producing the thermoplastic starch composition of this disclosure includes, as described above, a mixing step of mixing raw materials including 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 in the thermoplastic starch composition of this disclosure.

[0059] The mixing step will be explained in detail with an example. In the mixing step, for example, the starch and the plasticizer for starch are kneaded while being heated. By kneading, the thermoplastic starch composition of this disclosure is obtained. Examples of equipment for kneading include mills, despas, mixer kneaders, Banbury mixers, rolls, single-screw or multi-screw extruders, continuous kneaders, etc. Multiple kneaders may also be combined, for example, a 1.5-screw extruder which combines a single-screw and a twin-screw extruder. There are no particular limitations in this disclosure, but for example, from the viewpoint of production speed, multi-screw extruders and combinations thereof are preferred, and more preferably twin-screw extruders.

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

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

[0062] The mixing process does not require any particular order of mixing, as long as it plasticizes the starch and yields the thermoplastic starch composition of the Disclosure. For example, if the metal halide salt is included, 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 mixed in before being introduced into the kneading equipment.

[0063] There are no particular restrictions on the method of mixing the metal halide salt and the starch; for example, they may be mixed with the starch beforehand, or mixed simultaneously with the starch plasticizer. Alternatively, the metal halide salt may be added from a separate raw material inlet from the starch using an extruder or the like. From the viewpoint of dispersibility in the raw materials contained in the thermoplastic starch composition, it is preferable to mix the metal halide salt simultaneously with the starch plasticizer, and even more preferable to mix them beforehand.

[0064] Furthermore, the metal halide salt may be mixed as a solid, such as a powder, or as a liquid, such as an aqueous solution. From the viewpoint of dispersion, mixing as a liquid is preferable.

[0065] When low-molecular-weight starch is used as the starch, the method for producing the thermoplastic starch composition of this disclosure may further include, for example, a low-molecular-weight step of treating the starch to reduce its molecular weight in order to obtain low-molecular-weight starch. The low-molecular-weight step may be performed, for example, within the system of an extrusion molding machine for extruding the thermoplastic starch composition of this disclosure. When the low-molecular-weight step is performed within the system of the extrusion molding machine, it is preferable, for example, that the starch treatment method does not damage the extrusion molding machine.

[0066] [Manufacturing methods for pellets, flakes, etc.] After the kneading process, the thermoplastic starch composition extruded from a heated extrusion section may be molded into a suitable shape. The molded shape is not particularly limited, but examples include pellets, flakes, crumbs, powders, sheets, and chips. Alternatively, the mixture may be molded directly into the shape of a molded body after kneading. In this specification, molded products in the form of pellets, flakes, or sheets may simply be referred to as "pellets," "flakes," or "sheets."

[0067] When the pellets or flakes are to be formed as described above, for example, the pellets or flakes of the present disclosure can be manufactured as follows. The method for manufacturing the pellets or flakes of the present disclosure includes, as described above, 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-forming 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 by the 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, which is a strand, that has been extruded from the extrusion outlet by the extrusion step. As a method for turning the thermoplastic starch composition, which is a strand, into pellets or flakes, examples include a cold cut method in which the strand is air-cooled or water-cooled and then cut with a strand cutter, a hot cut method in which it is cut with a rotary cutter attached to the outlet of an extruder, an underwater cut method, etc. For example, from the viewpoint of quality stability, the cold cut method and the hot cut method are preferred, and the cold cut method is more preferred.

[0070] [Method for manufacturing compound bodies] As described above, the method for producing the compound of the present disclosure includes a first kneading step of kneading a raw material containing the pellets or flakes of the present disclosure with the thermoplastic resin. The raw material may include, for example, other thermoplastic resins, the other additives, etc.

[0071] [Method for manufacturing resin molded products] As described above, the method for manufacturing a resin molded article of the present disclosure includes a resin molding step of resin molding a raw material containing the compound of the present disclosure to produce a resin molded article. The resin molding step may include, for example, a second kneading step of kneading the compound of 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 to produce a resin molded article.

[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 carried out by, for example, conventionally known methods. Examples include calendering, thermoforming, extrusion blow molding, inflation molding, vacuum forming, casting, 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. [Examples]

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

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

[0075] [Viscosity measurement] 75 g of 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 mixture was held for 20 minutes and, without cooling, stirred for 1 minute at 15000 rpm using a homogenizer (Microtech Nichion Co., Ltd., product 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 then measured using a B-type viscometer (Toki Sangyo Co., Ltd., product name: TVB10M). Furthermore, viscosity X was calculated from the measured B-type viscosity using the aforementioned formula (1).

[0076] [MFR measurement] The melt flow rate (MFR) was measured at a temperature of 160°C and a load of 5 kg using a melt indexer (Toyo Seiki Co., Ltd., product name: G-02) in accordance with JIS K 7210. The measurement sample consisted of 30 g of pelletized thermoplastic starch composition, weighed onto an aluminum tray, spread out without overlapping, heated at 160°C for 30 minutes, and then allowed to cool at room temperature for 6 hours. The heat treatment was performed using a shelf-type forced-air dryer (Advantec Toyo Co., Ltd., product name: DRK632DC).

[0077] [Elongation at break] The compound obtained by the method described later was sandwiched between PET films and molded in a heat press (AS ONE Corporation, product name: H300-1) at 150°C and 0.8t for 6 minutes. The PET film and compound were then removed and cooled to room temperature to produce films with a thickness of 0.1 to 1.5 mm. The obtained films were left to stand at 23°C and 50% RH for one week, and then molded into dumbbell test pieces (JIS K 7127 Type 5) using a lever-type sample cutter (Dumbbell Co., Ltd., model number: SDL-100). Nine dumbbell test pieces were measured in a universal material testing machine (A&D Co., Ltd., model number: RTG-1210) at 23°C and 50% RH with a chuck distance of 70 mm and a tensile speed of 100 mm / min to measure the tensile elongation at break (elongation at break). The elongation at break was calculated as the average value of 7 samples, excluding the maximum and minimum values ​​from the measurement results of the 9 samples. Unless otherwise specified, the elongation at break (%GL) as defined herein refers to the result obtained by the method described above. Furthermore, the result obtained by the method described above is defined as a characteristic of the thermoplastic starch composition in this embodiment.

[0078] <Manufacturing of thermoplastic starch composition> (Materials used) In this example, the starches used were "unprocessed corn starch (Nippon Shokuhin Kako Co., Ltd., product name: Nisshoku Corn Starch Y (moisture content 13.2%))", "oxidized starch (Nippon 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 plasticizers for starch.

[0080] The following metal halide salts were used: "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, a slurry of starch (unprocessed cornstarch) was heated to 40°C to 50°C, and 4% by weight of hydrochloric acid was added to the starch. Five hours after adding the hydrochloric acid, 4% by weight of sodium hydroxide was added until the pH reached 7. The mixture was then dehydrated, and washed and dehydrated twice with five times the amount of water relative to the weight of the starch. Next, the wet cake was broken up and dried overnight at 40°C to obtain acid-treated starch.

[0082] (Preparation of starch treated with metal halide salts) 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 mixture was mixed with starch (unprocessed corn starch), reacted at 130°C, and allowed to cool at room temperature to obtain 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 and dewatered twice with 5 times the weight of the starch to remove the salt from the starch.

[0083] Note that the starch content listed in the table includes the water content of the starch. Also, in this example, "cornstarch" may be simply referred to as "corn."

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

[0085] (Manufacturing of pellets containing thermoplastic starch composition) The raw materials listed in Table 1 below were pre-mixed in a Kenwood mixer. The resulting mixture was supplied from a feeder installed above C1 (the inlet of the kneader) of a twin-screw extruder (φ20mm, L / D=45, Technovel Co., Ltd.). In this example, a twin-screw extruder was used to produce pellets, but the apparatus for producing pellets is not limited to this. The kneading temperature was adjusted so that the outlet product temperature (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 supplied to the inlet of a pelletizer (Technovel Co., Ltd., product name: SCP-203-2MT). The strands pulled by the pelletizer were cut inside the pelletizer to produce pellets containing the thermoplastic starch compositions of Example 1 and Comparative Example 1 listed in Table 1 below (test sections A-1 to A-10, and X-1 to A-3).

[0086] [Table 1-1]

[0087] [Table 1-2]

[0088] [Example 2, Comparative Example 2] The compounds of this example and comparative example were prepared by the following procedure.

[0089] (Production of compounds containing thermoplastic starch composition) As shown in Table 2 below, the thermoplastic starch compositions prepared in Example 1 and Comparative Example 1, thermoplastic resin (LDPE, Tosoh Corporation, trade name: Petrocene® LDPE183, MFR 2g / 10min (according to JIS K 6922-1), elongation at break 400.3%GL), and compatibilizer (Mitsui Chemicals, Inc., trade name: Admer HE-810) were placed in a polyethylene bag, the opening of the bag was tied, and the bag was shaken up and down and left and right to mix thoroughly. The entire amount was supplied from a feeder installed at the top of C1 of a twin-screw extruder (φ20mm, L / D=45, Technovel Corporation). The mixing temperature was adjusted so that the outlet product temperature was 159℃, and the shaft rotation speed was set to 150 rpm. The compound of the extruded strands was held in the hand, cooled in a water tank (Technovel Co., Ltd., product name: SCB150-1500), and supplied to the inlet of a pelletizer (Technovel Co., Ltd., product name: SCP-203-2MT). The strands, pulled by the pelletizer, were cut inside the pelletizer to produce pellet-shaped compound. The elongation at break (%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 this example and comparative example, compound bodies were prepared using thermoplastic resins with different fluidity levels.

[0094] Compounds for Example 3 and Comparative Example 3 were manufactured in the same manner as in Example 2, except that the thermoplastic resin was changed to a thermoplastic resin with different fluidity as listed in Table 3 below (LDPE, Tosoh Corporation, trade name: Petrocene® LDPE212, MFR 13g / 10min (according to JIS K 6922-1), elongation at break 317.3%GL; LDPE, Tosoh Corporation, trade name: Petrocene® LDPE249, MFR 70g / 10min (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 this example and comparative example, the type of thermoplastic resin was changed to polypropylene (PP) to prepare the compound.

[0098] The compound bodies of Example 4 and Comparative Example 4 were manufactured in the same manner as in Example 2, except that the thermoplastic resin was changed to the thermoplastic resin listed in Table 4 below (PP, Sun Allomer Co., Ltd., product name: PF621S, MFR 6.5g / 10min (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 outlet product temperature was 180°C.

[0099] [Table 4]

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

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

[0102] [Table 5]

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

[0104] As shown in Table 6 below, the compounds 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 thermoplastic resin were changed.

[0105] [Table 6]

[0106] As shown in Table 1, the thermoplastic starch composition containing a metal halide salt in Example 1, and the thermoplastic starch composition prepared using pre-treated low-molecular-weight starch, both exhibited lower viscosity compared to test sections X-1 to X-3, which contained unprocessed corn starch, and fluidity was observed in MFR measurements. In test sections A-9 and X-2, the starch content was reduced and the glycerol content was increased, but even under these conditions, the viscosity was reduced by incorporating a metal halide salt, and fluidity was observed in MFR measurements. Furthermore, fluidity was also observed in A-10, which had increased starch content and decreased glycerol content.

[0107] As shown in Table 2, the test plots of the Examples showed higher elongation at break than the Comparative Example under conditions in which thermoplastic starch compositions containing glycerol or sorbitol as a starch plasticizer and LDPE183 as a thermoplastic resin were used. In other words, the Examples showed less change in elongation at break from the raw material LDPE183 compared to the Comparative Example. This trend was similar regardless of whether a compatibilizer was added or not.

[0108] As shown in Table 3, even when the thermoplastic resin was changed to other PEs with different fluidity, the elongation at break in the examples (test sections B2-1 to B2-6) was superior to that of the comparative examples (test sections 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 sections B3-1 to B3-2) was superior to that of the comparative example (test section B3X-1).

[0110] As shown in Table 5, even when the thermoplastic resin was changed to PBS, the elongation at break of Example (Test Group B4-1) was superior to that of the Comparative Example (Test Group B4X-1).

[0111] As shown in Table 6, even with a high concentration of thermoplastic starch composition, the elongation at break 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] <Note> The above embodiments and some or all of the examples may also be described as follows, but are not limited to these. (Note 1) A thermoplastic starch composition, Contains starch and a plasticizer for starch, The thermoplastic starch composition, diluted to 15% by weight with water, is heated in a water bath to 95°C, stirred at 400 rpm for 20 minutes, dispersed using a homogenizer at 15000 rpm for 1 minute, cooled to 70°C in a water bath, and the viscosity measured by a B-type viscometer is 270 mPa·s or less. Thermoplastic starch composition. (Note 2) The viscosity X calculated by the following formula (1) is 270 mPa·s or less. The thermoplastic starch composition described in Appendix 1. X = A + (73 - B) × 6.57 (1) In the above formula (1), A is the viscosity measured by a B-type viscometer after adding the thermoplastic starch composition to water to a concentration of 15% by weight, heating to 95°C in a water bath, stirring at 400 rpm for 20 minutes, dispersing using a homogenizer at 15000 rpm for 1 minute, and cooling to 70°C in a water bath. B is the starch content when the total weight of all components other than water contained in the thermoplastic starch composition is set to 100% by weight. (Note 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 60-95% by weight. The content of the aforementioned starch plasticizer is 5 to 35% by weight. The thermoplastic starch composition described in Appendix 1 or 2. (Note 4) A thermoplastic starch composition, Contains 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 60-95% by weight. The content of the aforementioned starch plasticizer is 5 to 35% by weight. The melt flow rate of the thermoplastic starch composition at a temperature of 160°C and a load of 5 kg, in accordance with JIS K 7210, is 0.01 g / 10 min or more. Thermoplastic starch composition. (Note 5) The aforementioned starch includes low molecular weight starch, The aforementioned low molecular weight starch is washed low molecular weight starch. A thermoplastic starch composition as described in any of the appendices 1 to 4. (Note 6) The thermoplastic starch composition according to Appendix 5, wherein the low molecular weight starch is a metal halide salt-treated starch obtained by treating it with a metal halide salt to reduce its molecular weight. (Note 7) The thermoplastic starch composition according to any one of Appendix 1 to 6, comprising at least one of polyhydric alcohols and sugars as the plasticizer for starch. (Note 8) The polyhydric alcohols are at least one selected from the group consisting of glycerin, propylene glycol, and ethylene glycol. The aforementioned sugar is at least one of sorbitol and glucose. The thermoplastic starch composition described in Appendix 7. (Note 9) Furthermore, it contains metal halide salts, 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. A thermoplastic starch composition as described in any of the appendices 1 to 8. (Note 10) The thermoplastic starch composition according to any one of the appendices 1 to 9, wherein the plasticizer for starch substantially contains no water. (Note 11) Pellets containing the thermoplastic starch composition described in any of the appendices 1 to 10. (Note 12) Flakes containing the thermoplastic starch composition described in any of the appendices 1 to 10. (Note 13) A compound comprising the thermoplastic starch composition described in any of the appendices 1 to 10. (Note 14) A resin molded article containing a thermoplastic starch composition as described in any of the appendices 1 to 10. (Note 15) The process includes a mixing step of mixing raw materials containing the starch and the plasticizer for the starch, A method for producing a thermoplastic starch composition as described in any of Appendix 1 to 10. (Note 16) Furthermore, the process includes a molecular weight reduction step to obtain low molecular weight starch by treating the starch to reduce its molecular weight, The mixing step is a step of mixing raw materials including the low molecular weight starch and the starch plasticizer. The manufacturing method described in Appendix 15. (Note 17) The manufacturing method according to Appendix 16, wherein the molecular weight reduction step is performed within the system of an extruder for extruding the thermoplastic starch composition. (Note 18) A strand forming step involves extruding a thermoplastic starch composition to form strands, The process includes a strand cutting step of cutting the strand to form pellets or flakes, A method for producing pellets or flakes, wherein the thermoplastic starch composition is the thermoplastic starch composition described in any of the appendices 1 to 10. (Note 19) The process includes a first kneading step of kneading a raw material containing pellets with a raw material containing thermoplastic resin, A method for producing a compound, wherein the pellets are the pellets described in Appendix 11. (Note 20) The process includes a first kneading step of kneading a raw material containing flakes with a raw material containing a thermoplastic resin, A method for producing a compound, wherein the aforementioned flakes are the flakes described in Appendix 12. (Note 21) The process includes a resin molding step in which a raw material containing a compound is resin-molded to produce a resin molded product, A method for manufacturing a resin molded product, wherein the compound body is the compound body described in Appendix 13. (Note 22) A second kneading step in which the compound body is kneaded with a raw material containing other thermoplastic resins, The process includes a resin molding step in which the kneaded material obtained in the second kneading step is resin-molded to produce a resin molded product, A method for manufacturing a resin molded product as described in Appendix 21. [Industrial applicability]

[0113] As described above, this disclosure can provide a thermoplastic starch composition having fluidity, pellets, flakes, compounds, resin molded articles, a method for producing a thermoplastic starch composition, a method for producing pellets or flakes, a method for producing a compound, and a method for producing a resin molded article. This disclosure can, for example, provide a thermoplastic starch composition having fluidity, and a masterbatch of a thermoplastic starch composition. Furthermore, for example, by kneading the thermoplastic starch composition of this disclosure with a thermoplastic resin, a compound with a high starch content can be efficiently mass-produced. For example, by supplying a thermoplastic starch composition with high fluidity, i.e., low B-type viscosity, a compound exhibiting better physical properties than conventional pastes with high B-type viscosity thermoplastic starch compositions can be provided, for example, a compound exhibiting a high elongation at break value can be provided. For example, by supplying a thermoplastic starch composition with high fluidity, i.e., high MFR, a compound exhibiting better physical properties than conventional pastes with low MFR thermoplastic starch compositions can be provided, for example, a compound exhibiting a high elongation at break value can be provided. The uses of the present disclosure are not particularly limited. For example, the uses of the thermoplastic starch compositions of the present disclosure are not limited to the pellets, flakes, and resin molded products of the present disclosure, but are arbitrary and can be used in a wide range of applications.

Claims

1. A thermoplastic starch composition, Contains starch and a plasticizer for starch, The aforementioned plasticizer for starch contains at least one of polyhydric alcohols and sugars. The thermoplastic starch composition, diluted to 15% by weight with water, is heated to 95°C in a water bath, stirred at 400 rpm for 20 minutes, dispersed using a homogenizer at 15,000 rpm for 1 minute, cooled to 70°C in a water bath, and the viscosity measured by a B-type viscometer is 270 mPa·s or less. The total weight of all components other than water contained in the thermoplastic starch composition is set to 100% by weight. The starch content is 60 to 85% by weight. The content of the aforementioned starch plasticizer is 15 to 35% by weight. Thermoplastic starch composition.

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

3. A thermoplastic starch composition, Contains starch and a plasticizer for starch, The aforementioned plasticizer for starch contains at least one of polyhydric alcohols and sugars. The total weight of all components other than water contained in the thermoplastic starch composition is set to 100% by weight. The starch content is 60 to 85% by weight. The content of the aforementioned starch plasticizer is 15 to 35% by weight. The melt flow rate of the thermoplastic starch composition at a temperature of 160°C and a load of 5 kg, in accordance with JIS K 7210, is 0.01 g / 10 min or more. Thermoplastic starch composition.

4. The aforementioned starch includes low molecular weight starch, The aforementioned low molecular weight starch is washed low molecular weight starch. The thermoplastic starch composition according to any one of claims 1 to 3.

5. The thermoplastic starch composition according to claim 4, wherein the low molecular weight starch is a metal halide salt-treated starch that has been treated to reduce molecular weight with a metal halide salt.

6. The polyhydric alcohols are at least one selected from the group consisting of glycerin, propylene glycol, and ethylene glycol. The aforementioned sugar is at least one of sorbitol and glucose. The thermoplastic starch composition according to claim 5.

7. The thermoplastic starch composition according to any one of claims 1 to 3, wherein the plasticizer for starch substantially contains no water.

8. A pellet comprising the thermoplastic starch composition according to any one of claims 1 to 3.

9. A flake comprising the thermoplastic starch composition according to any one of claims 1 to 3.

10. A compound comprising the thermoplastic starch composition according to any one of claims 1 to 3.

11. A resin molded article comprising the thermoplastic starch composition according to any one of claims 1 to 3.

12. The process includes a mixing step of mixing raw materials containing the starch and the plasticizer for the starch, A method for producing a thermoplastic starch composition according to any one of claims 1 to 3.

13. Furthermore, the process includes a molecular weight reduction step to obtain low molecular weight starch by treating the starch to reduce its molecular weight, The mixing step is a step of mixing raw materials including the low molecular weight starch and the starch plasticizer. The manufacturing method according to claim 12.

14. The manufacturing method according to claim 13, wherein the molecular weight reduction step is performed within the system of an extruder for extruding the thermoplastic starch composition.

15. A strand forming step involves extruding a thermoplastic starch composition to form strands, The process includes a strand cutting step of cutting the strand to form pellets or flakes, A method for producing pellets or flakes, wherein the thermoplastic starch composition is the thermoplastic starch composition described in any one of claims 1 to 3.

16. The process includes a first kneading step of kneading a raw material containing pellets with a raw material containing thermoplastic resin, A method for producing a compound, wherein the pellet is the pellet described in claim 8.

17. The process includes a first kneading step of kneading a raw material containing flakes with a raw material containing a thermoplastic resin, A method for producing a compound, wherein the aforementioned flakes are the flakes described in claim 9.

18. The process includes a resin molding step in which a raw material containing a compound is resin-molded to produce a resin molded product, A method for manufacturing a resin molded product, wherein the compound body is the compound body described in claim 10.

19. A second kneading step involves kneading the aforementioned compound with a raw material containing other thermoplastic resins, The process includes a resin molding step, in which the kneaded material obtained in the second kneading step is resin-molded to produce a resin molded product, A method for producing a resin molded product according to claim 18.

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