Resin composition and method for producing same

Abstract

To provide a resin composition that has excellent stretchability and retains excellent impact strength even when put under low-temperature and low-humidity conditions for a long time.SOLUTION: A resin composition contains 6-45 pts.mass of modified starch (A), 1-5 pts.mass of a water-soluble polymer (B), 1-50 pts.mass of a polyol plasticizer (C) and 5-80 pts.mass of a thermoplastic resin (D), and satisfies the following formula (1): 0<mass of (A) / mass of (C)<1, the total content of the (A), (B), (C) and (D) being 100 pts.mass.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition used for food packaging containers and the like and a method for producing the same, a film or sheet made of the resin composition, a laminate including a layer made of the resin composition and a method for producing the same, and a container made of the laminate. [Background technology]

[0002] BACKGROUND ART Resin compositions containing modified starch and water-soluble polymers have been widely used in food packaging containers because of their excellent biodegradability (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2013-216918 Summary of the Invention [Problem to be solved by the invention]

[0004] Resin compositions used in these food packaging containers are required to be biodegradable, durable under harsh conditions, and stretchable from the viewpoint of thermoformability. However, according to the studies of the present inventors, conventional resin compositions can lose impact strength when exposed to low temperature and low humidity for a long period of time, which are considered to be unfavorable conditions for modified starch. Furthermore, even if the impact strength can be ensured, the stretchability is conversely reduced, and therefore it is not possible to achieve both stretchability and impact strength under low temperature and low humidity.

[0005] Therefore, an object of the present invention is to provide a resin composition that has excellent stretchability and also has excellent impact strength even when exposed to low temperature and low humidity for a long period of time, a method for producing the same, a film or sheet made of the resin composition, a laminate including a layer made of the resin composition and a method for producing the same, and a container made of the laminate. [Means for solving the problem]

[0006] As a result of extensive research to solve the above problems, the present inventors have found that the above problems can be solved if a resin composition contains 6 to 45 parts by mass of modified starch (A), 1 to 5 parts by mass of water-soluble polymer (B), 1 to 50 parts by mass of polyol plasticizer (C), and 5 to 80 parts by mass of thermoplastic resin (D), respectively, and the mass of polyol plasticizer (C) is greater than the mass of starch (A), and have completed the present invention. That is, the present invention includes the following aspects.

[0007] [1] 6 to 45 parts by mass of modified starch (A), 1 to 5 parts by mass of a water-soluble polymer (B), 1 to 50 parts by mass of a polyol plasticizer (C), and 5 to 80 parts by mass of a thermoplastic resin (D) different from the water-soluble polymer (B). The formula (1) is as follows: 0<(A) mass / (C) mass<1 (1) and the total content of (A), (B), (C) and (D) is 100 parts by mass. [2] The resin composition according to [1], wherein the total content of the modified starch (A), the water-soluble polymer (B), the polyol plasticizer (C) and the thermoplastic resin (D) is 80 mass% or more relative to the mass of the resin composition. [3] The resin composition according to [1] or [2], wherein the average amylose content of the modified starch (A) is 45% by mass or more. [4] The resin composition according to any one of [1] to [3], wherein the water-soluble polymer (B) is a polyvinyl alcohol-based resin. [5] The resin composition according to any one of [1] to [4], wherein the polyol plasticizer (C) comprises at least one selected from the group consisting of sorbitol, maltitol, xylitol, erythritol, sucrose, mannitol, lactitol, arabinose, xylose, fructose, glucose, galactose, ribose, trehalose, and glycerol. [6] The resin composition according to any one of [1] to [5], wherein the thermoplastic resin (D) comprises at least one selected from polyolefin-based resins and polyester-based resins. [7] The resin composition according to any one of [1] to [6], wherein the thermoplastic resin (D) comprises a biodegradable thermoplastic resin that is biodegradable in a biodegradability test in accordance with EN13432. [8] A film or sheet made of the resin composition according to any one of [1] to [7]. [9] An L1 layer made of the resin composition according to any one of [1] to [7]; an L2 layer different from the L1 layer and containing 50% by mass or more of the same thermoplastic resin (D) as the L1 layer, and / or an L3 layer containing 50% by mass or more of modified starch; A laminate comprising:

[10] A layer structure having an L3 layer / L1 layer / L3 layer in this order; A layer structure having an L2 layer / L1 layer / L3 layer in this order, and Layer structure consisting of L2 layer / L1 layer / L2 layer in this order The laminate according to [9], which at least partially comprises a layer structure selected from the group consisting of:

[11] The laminate according to [9] or

[10] , wherein the thickness of at least one L1 layer is 10 to 450 μm, the thickness of at least one L2 layer is 5 to 500 μm, and the thickness of at least one L3 layer is 20 to 800 μm.

[12] The laminate according to any one of [9] to

[11] , wherein the total thickness of the L1 layers is 10 to 1000 μm, the total thickness of the L2 layers is 5 to 1000 μm, and the total thickness of the L3 layers is 20 to 2000 μm.

[13] A material (X1) comprising a modified starch (A) and a water-soluble polymer (B), and optionally a polyol plasticizer (C) and / or a thermoplastic resin (D); a material (X2) containing a polyol plasticizer (C) and / or a thermoplastic resin (D); A method for producing the resin composition according to any one of [1] to [7], comprising a step of mixing the above.

[14] The method according to

[13] , wherein in the step, the material (X1) contains at least a modified starch (A), a water-soluble polymer (B), and a thermoplastic resin (D), and the material (X2) contains at least a polyol plasticizer (C).

[15] The method according to

[13] or

[14] , wherein the step is a step of melt-kneading the material (X1) that is a laminate and the material (X2).

[16] The method according to

[15] , wherein the laminate is a laminate according to any one of [9] to

[12] .

[17] A method for producing a laminate according to any one of [9] to

[12] , comprising a step of co-extrusion molding the L1 layer and other layers including the L2 layer and / or the L3 layer.

[18] A container comprising the laminate according to any one of [9] to

[12] . [Effects of the Invention]

[0008] The resin composition of the present invention has excellent stretchability and excellent impact strength even when exposed to low temperature and low humidity for a long period of time, and is therefore suitable for use as a material for food packaging and containers. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing a recycling scheme of a laminate according to one embodiment of the present invention. [Figure 2] FIG. 1 is a schematic diagram of a twin-screw extruder used in the examples. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Resin composition] The resin composition of the present invention comprises 6 to 45 parts by mass of modified starch (A), 1 to 5 parts by mass of a water-soluble polymer (B), 1 to 50 parts by mass of a polyol plasticizer (C), and 5 to 80 parts by mass of a thermoplastic resin (D) different from the water-soluble polymer (B), and is represented by the following formula (1): 0<(A) mass / (C) mass<1 (1) The total content of (A), (B), (C) and (D) is 100 parts by mass.

[0011] The present inventors have unexpectedly discovered that incorporating modified starch (A), water-soluble polymer (B), polyol plasticizer (C), and thermoplastic resin (D) in the above-described proportions results in enhanced compatibility, thereby improving the stretchability of the resin composition and even improving impact strength under low temperature and low humidity conditions. Furthermore, the present inventors have discovered that the resin composition of the present invention also exhibits excellent interlayer adhesive strength in a laminate containing the resin composition and excellent recyclability of the resin composition. In this specification, the stretchability of the resin composition, impact strength under low temperature and low humidity conditions, and recyclability of the resin composition are sometimes simply referred to as stretchability, impact strength, and recyclability, and the interlayer adhesive strength of the resulting laminate is sometimes simply referred to as adhesive strength. Furthermore, the modified starch (A) may be referred to as component (A) or simply (A), the water-soluble polymer (B) as component (B) or simply (B), the polyol plasticizer (C) as component (C) or simply (C), and the thermoplastic resin (D) as component (D) or simply (D).

[0012] <Modified starch (A)> The modified starch (A) is preferably at least one selected from the group consisting of, for example, etherified starch, esterified starch, cationized starch, and crosslinked starch.

[0013] Examples of starches include starches derived from cassava, corn, potato, sweet potato, sago, tapioca, sorghum, beans, bracken, lotus, water chestnut, wheat, rice, oats, arrowroot, and peas. Among these, starches derived from corn and cassava are preferred, and starches derived from high-amylose corn are more preferred. Starches can be used alone or in combination of two or more types.

[0014] Examples of etherified starches include alkyl-etherified starches such as methyl-etherified starch, carboxyalkyl-etherified starches such as carboxymethyl-etherified starch, and hydroxyalkyl-etherified starches such as etherified starches having a hydroxyalkyl group having 2 to 6 carbon atoms. Allyl-etherified starch can also be used.

[0015] Examples of esterified starches include esterified starches having structural units derived from carboxylic acids, such as esterified starches having structural units derived from acetic acid; esterified starches having structural units derived from dicarboxylic acid anhydrides, such as esterified starches having structural units derived from maleic anhydride, phthalic anhydride, and octenylsuccinic anhydride; and esterified starches having structural units derived from oxoacids, such as nitrate-esterified starch, phosphate-esterified starch, and urea-phosphate-esterified starch. Other examples include xanthate-esterified starch, acetoacetate-esterified starch, and the like.

[0016] Examples of the cationized starch include a reaction product of starch with 2-diethylaminoethyl chloride, and a reaction product of starch with 2,3-epoxypropyltrimethylammonium chloride.

[0017] Examples of crosslinked starches include formaldehyde crosslinked starch, epichlorohydrin crosslinked starch, phosphate crosslinked starch, and acrolein crosslinked starch.

[0018] From the viewpoint of easily improving stretchability, impact strength, adhesive strength, and recyclability, the modified starch (A) is preferably at least one selected from the group consisting of etherified starches having a hydroxyalkyl group having 2 to 6 carbon atoms and esterified starches having structural units derived from dicarboxylic acid anhydrides, and more preferably at least one selected from the group consisting of hydroxyethyl etherified starch, hydroxypropyl etherified starch, hydroxybutyl etherified starch, esterified starch having structural units derived from maleic anhydride, esterified starch having structural units derived from phthalic anhydride, and esterified starch having structural units derived from octenylsuccinic anhydride. The modified starches (A) can be used alone or in combination of two or more. In this specification, the number of carbon atoms listed before "starch" refers to the number of carbon atoms in the group substituted with one hydroxyl group in the starch (the group formed by modifying one hydroxyl group in the starch). For example, etherified starch having a hydroxyalkyl group with 2 to 5 carbon atoms indicates that the hydroxyalkyl group formed by modifying one hydroxyl group in the starch has 2 to 5 carbon atoms.

[0019] The etherified starch having a hydroxyalkyl group having 2 to 6 carbon atoms may be obtained by reacting starch with an alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide, etc. The average number of hydroxy groups used for modification is preferably 0.05 to 2 per glucose unit in the starch.

[0020] The average amylose content of the modified starch (A) is preferably 45% by mass or more, more preferably 50% by mass or more, and even more preferably 55% by mass or more. When the average amylose content is equal to or greater than the above-mentioned lower limit, stretchability, impact strength, adhesive strength, recyclability, and biodegradability are likely to be improved. The average amylose content of the modified starch (A) is usually 90% by mass or less. In this specification, the amylose content can be measured, for example, by the iodine coloring method described in "Starch 50 No. 4 158-163 (1998)." When one type of modified starch is used, the average amylose content refers to the amylose content of the one type of modified starch. When two or more types of modified starches are used, the average amylose content refers to the weighted average of the amylose contents of the two or more types of modified starches. Therefore, for example, when two or more types of modified starches are used to provide an average amylose content of 45% by mass or more, the starch may contain a modified starch with an amylose content of less than 45% by mass.

[0021] The modified starch (A) may preferably have a moisture content of 5 to 15% by mass.

[0022] Commercially available modified starch (A) can also be used. Typical commercially available examples of modified starch (A) include ECOFILM (trademark) and National 1658 (trademark), which are hydroxypropyl etherified starches manufactured by Ingredione.

[0023] The content of the modified starch (A) is 6 to 45 parts by mass relative to 100 parts by mass of the total of the components (A), (B), (C), and (D). If the content of the modified starch (A) is less than 6 parts by mass and more than 45 parts by mass, the stretchability, impact strength, adhesive strength, and recyclability tend to decrease. The content of the modified starch (A) is 6 parts by mass or more, preferably 7 parts by mass or more, more preferably 8 parts by mass or more, and even more preferably 9 parts by mass or more, and is 45 parts by mass or less, preferably 40 parts by mass or less, more preferably 35 parts by mass or less, even more preferably 30 parts by mass or less, still more preferably 25 parts by mass or less, and particularly preferably 20 parts by mass or less. When the content of the modified starch (A) is within the above range, stretchability, impact strength, adhesive strength, and recyclability are likely to be improved.

[0024] <Water-soluble polymer (B)> The water-soluble polymer (B) is not particularly limited as long as it is a water-soluble polymer, but is preferably a polyvinyl alcohol-based resin. Examples of the polyvinyl alcohol-based resin include an ethylene-vinyl alcohol copolymer, polyvinyl alcohol, and polyvinyl acetal. Among these, polyvinyl alcohol is preferred from the viewpoint of easily improving stretchability.

[0025] The saponification degree of polyvinyl alcohol is preferably 80 to 99.8 mol%. When the saponification degree of polyvinyl alcohol (B) is within the above range, stretchability, impact strength, adhesive strength, and recyclability are likely to be improved. The saponification degree is more preferably 85 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and still more preferably 98 mol% or more. In this specification, the saponification degree refers to the molar fraction of hydroxyl groups relative to the total of hydroxyl groups and ester groups in polyvinyl alcohol.

[0026] Polyvinyl alcohol may further contain other monomer units in addition to vinyl alcohol units, such as monomer units derived from ethylenically unsaturated monomers. Examples of ethylenically unsaturated monomers include α-olefins such as ethylene, propylene, n-butene, isobutylene, and 1-hexene; acrylic acid and its salts; unsaturated monomers having an acrylic ester group; methacrylic acid and its salts; unsaturated monomers having a methacrylic ester group; acrylamide, N-methylacrylamide, N-ethylacrylamide, N,N-dimethylacrylamide, diacetoneacrylamide, acrylamidopropanesulfonic acid and its salts, acrylamidopropyldimethylamine and its salts (e.g., quaternary salts); methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, methacrylamidopropanesulfonic acid and its salts, methacrylamidopropyldimethylamine and its salts (e.g., quaternary salts); methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, vinyl halides such as vinyl chloride and vinyl fluoride; vinylidene halides such as vinylidene chloride and vinylidene fluoride; allyl compounds such as allyl acetate, 2,3-diacetoxy-1-allyloxypropane and allyl chloride; unsaturated dicarboxylic acids such as maleic acid, itaconic acid and fumaric acid, and salts or esters thereof; vinyl silyl compounds such as vinyltrimethoxysilane; isopropenyl acetate; and vinyl ester monomers such as vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatate, vinyl caproate, vinyl carboxylate, vinyl laurate, vinyl palmitate, vinyl stearate, vinyl oleate and vinyl benzoate. The content of other monomer units is preferably 10 mol % or less, and more preferably 5 mol % or less.

[0027] The method for producing polyvinyl alcohol is not particularly limited. For example, a method can be used in which a vinyl alcohol monomer and optionally other monomers are polymerized, and the resulting polymer is saponified to convert it into vinyl alcohol units. Polymerization methods include batch polymerization, semi-batch polymerization, continuous polymerization, and semi-continuous polymerization. Polymerization methods include known methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. Known methods can be used for saponification of the polymer. For example, saponification can be performed in a state in which the polymer is dissolved in alcohol or aqueous alcohol. The alcohol that can be used in this case is preferably a lower alcohol such as methanol or ethanol.

[0028] The viscosity of the water-soluble polymer (B), as a 4% aqueous solution, at 20°C, measured in accordance with JIS Z 8803, is preferably 1 mPa·s or more, more preferably 2 mPa·s or more, even more preferably 3 mPa·s or more, and preferably 45 mPa·s or less, more preferably 35 mPa·s or less. When the viscosity of the water-soluble polymer (B) is within the above range, stretchability, impact strength, adhesive strength, and recyclability are likely to be improved. The viscosity of the water-soluble polymer (B) can be measured using a viscometer, for example, by the method described in the Examples.

[0029] The content of the water-soluble polymer (B) is 1 to 5 parts by mass relative to 100 parts by mass of the total of the components (A), (B), (C), and (D). If the content of the water-soluble polymer (B) is less than 1 part by mass or more than 5 parts by mass, the stretchability and impact strength tend to decrease. The content of the water-soluble polymer (B) is 1 part by mass or more, preferably 1.2 parts by mass or more, and 5 parts by mass or less, preferably 4.5 parts by mass or less, more preferably 4.0 parts by mass or less, even more preferably 3.5 parts by mass or less, and still more preferably 3.0 parts by mass or less. When the content of the water-soluble polymer (B) is within the above range, stretchability and impact strength are likely to be improved.

[0030] <Polyol plasticizer (C)> The polyol plasticizer (C) is not particularly limited, but examples thereof include sorbitol, maltitol, xylitol, erythritol, sucrose, mannitol, lactitol, arabinose, xylose, fructose, glucose, galactose, ribose, trehalose, glycerol, ethylene glycol, and propylene glycol. These polyol plasticizers (C) can be used alone or in combination. Among these, from the viewpoint of easily improving stretchability, impact strength, and recyclability, it is preferable to include at least one selected from the group consisting of sorbitol, maltitol, xylitol, erythritol, sucrose, mannitol, lactitol, arabinose, xylose, fructose, glucose, galactose, ribose, trehalose, and glycerol, and more preferably to include at least one selected from the group consisting of sorbitol, xylitol, and sucrose. The polyol plasticizer may be, for example, a commercially available product.

[0031] The content of the polyol plasticizer (C) is 1 to 50 parts by mass relative to 100 parts by mass of the total of the components (A), (B), (C), and (D). If the content of the polyol plasticizer (C) is less than 1 part by mass and exceeds 50 parts by mass, the stretchability, impact strength, and recyclability tend to decrease. The content of the polyol plasticizer (C) is 1 part by mass or more, preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 15 parts by mass or more, and is 50 parts by mass or less, preferably 45 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 35 parts by mass or less, and particularly preferably 30 parts by mass or less. When the content of the polyol plasticizer (C) is within the above range, stretchability, impact strength, and recyclability are likely to be improved.

[0032] <Thermoplastic resin (D)> The thermoplastic resin (D) is not particularly limited, but examples thereof include polyester resins, olefin resins, polyvinyl resins, polyacrylic resins, polycarbonate resins, polythiocarbonate resins, polyacetal resins, polyamide resins, polyphenylene ether resins, polysulfone resins, polyphenylene sulfide resins, polyimide resins, polyether ketone resins, and thermoplastic elastomers. These thermoplastic resins (D) can be used alone or in combination. Among these, from the viewpoint of easily improving stretchability, impact strength, adhesive strength, and recyclability, it is preferable that the thermoplastic resin (D) contains at least one selected from polyolefin resins and polyester resins. In addition, in one embodiment of the present invention, the thermoplastic resin (D) is preferably a water-insoluble resin.

[0033] Examples of polyolefin resins include linear polyolefin resins such as polyethylene, polypropylene, and polymethylpentene, and cyclic polyolefin resins such as cyclopentadiene and norbornene. Among these, from the viewpoint of easily improving stretchability, impact strength, adhesive strength, and recyclability, linear polyolefin resins are preferred, and polyethylene (for example, low-density polyethylene), polypropylene, etc. are more preferred. The polyolefin resins can be used alone or in combination of two or more.

[0034] Polyethylene refers to a polymer whose main component is a structural unit derived from ethylene, and polypropylene refers to a polymer whose main component is a structural unit derived from propylene. Polyethylene and polypropylene may each further contain other structural units in addition to the structural units described above. Examples of other structural units include the above-mentioned ethylenically unsaturated monomers other than ethylene or propylene. The content of other monomer units is preferably 10 mol% or less, more preferably 5 mol% or less. For example, commercially available polyethylene or polypropylene can be used.

[0035] The polyester resin refers to a polymer in which the main bond in the main chain is an ester bond, such as one having a dicarboxylic acid-derived structural unit and a diol-derived structural unit, or one having a hydroxycarboxylic acid-derived structural unit. When a polyester resin is used as the thermoplastic resin (D), the resin composition of the present invention is likely to have improved stretchability, impact strength, adhesive strength, and biodegradability, and is particularly excellent in biodegradability and adhesive strength. In this specification, the term "structural unit derived from" may be simply referred to as "unit." For example, a structural unit derived from a dicarboxylic acid is referred to as a dicarboxylic acid unit, a structural unit derived from a diol is referred to as a diol unit, and a structural unit derived from a hydroxycarboxylic acid is referred to as a hydroxycarboxylic acid unit.

[0036] When the thermoplastic resin (D) is a polyester resin, examples of the dicarboxylic acid constituting the dicarboxylic acid unit include aliphatic dicarboxylic acids such as malonic acid, succinic acid, adipic acid, azelaic acid, and sebacic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, norbornenedicarboxylic acid, and tricyclodecanedicarboxylic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, biphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenylketonedicarboxylic acid, sodium sulfoisophthalate, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid; and ester-forming derivatives thereof. Among these, aliphatic dicarboxylic acids or aromatic dicarboxylic acids are preferred, aromatic dicarboxylic acids are more preferred, and terephthalic acid is even more preferred, from the viewpoint of easily increasing adhesive strength and recyclability. Dicarboxylic acids can be used alone or in combination. When the polyester resin contains aromatic dicarboxylic acid units, the content of the aromatic dicarboxylic acid units is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more, based on the total molar amount of all constituent units derived from dicarboxylic acids.

[0037] When the thermoplastic resin (D) is a polyester resin, examples of the diol constituting the diol unit include aliphatic diols such as ethylene glycol, trimethylene glycol, butylene glycol (tetramethylene glycol), hexamethylene glycol, neopentyl glycol, methylpentanediol, and diethylene glycol; alicyclic diols such as cyclohexanedimethanol (e.g., 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, and 1,4-cyclohexanedimethanol), norbornene dimethanol, and tricyclodecane dimethanol; and aromatic diols such as bisphenol compounds and hydroquinone compounds. Among these, aliphatic diols are preferred, with ethylene glycol, trimethylene glycol, and butylene glycol being preferred, and butylene glycol being more preferred, from the viewpoint of easily increasing adhesive strength and recyclability. The diols can be used alone or in combination of two or more. When the polyester resin contains diol units, the content of the aliphatic diol units is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more, based on the total molar amount of all constituent units derived from diols.

[0038] In one embodiment of the present invention, when the polyester resin contains dicarboxylic acid units and diol units, the ratio of the dicarboxylic acid units to the diol units is preferably 10:1 to 1:10, more preferably 5:1 to 1:5, even more preferably 2:1 to 1:2, and particularly preferably 1:1.

[0039] When the thermoplastic resin (D) is a polyester resin, examples of the hydroxycarboxylic acid constituting the hydroxycarboxylic acid unit include aliphatic hydroxycarboxylic acids such as 10-hydroxyoctadecanoic acid, lactic acid, hydroxyacrylic acid, 2-hydroxy-2-methylpropionic acid, and hydroxybutyric acid; alicyclic hydroxycarboxylic acids such as hydroxymethylcyclohexanecarboxylic acid, hydroxymethylnorbornenecarboxylic acid, and hydroxymethyltricyclodecanecarboxylic acid; aromatic hydroxycarboxylic acids such as hydroxybenzoic acid, hydroxytoluic acid, hydroxynaphthoic acid, 3-(hydroxyphenyl)propionic acid, hydroxyphenylacetic acid, and 3-hydroxy-3-phenylpropionic acid; and ester-forming derivatives thereof. Among these, aliphatic hydroxycarboxylic acids are preferred, with lactic acid and hydroxybutyric acid being more preferred, and lactic acid being even more preferred, from the viewpoint of easily increasing adhesive strength and recyclability. These hydroxycarboxylic acids can be used alone or in combination.

[0040] The polyester resin may have the dicarboxylic acid unit and the diol unit, or the hydroxycarboxylic acid unit, or a combination of these structural units. The polyester resin may also contain structural units other than the dicarboxylic acid unit, the diol unit, and the hydroxycarboxylic acid unit, as long as the effects of the present invention are not impaired.

[0041] In one embodiment of the present invention, the polyester resin may be a copolymer of butylene adipate and butylene terephthalate [PBAT, poly(butylene adipate-co-butylene terephthalate)], a copolymer of butylene succinate and butylene adipate [PBSA, poly(butylene succinate-co-butylene adipate)], polylactic acid (PLA), polybutylene succinate, polyhydroxybutyrate (PHB), polyethylene terephthalate copolymer (PETG), or a mixture thereof. From the viewpoint of easily increasing adhesive strength and recyclability, PBAT, PLA, PETG, or a mixture thereof is preferred, and PBAT, PLA, or a mixture thereof is more preferred.

[0042] In one embodiment of the present invention, the thermoplastic resin (D) preferably contains a biodegradable thermoplastic resin or a biodegradable polyester resin that is biodegradable in a biodegradability test in accordance with EN 13432. By including such a thermoplastic resin, biodegradability can be enhanced. When the thermoplastic resin (D) contains a biodegradable thermoplastic resin, the content of the biodegradable thermoplastic resin is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, and particularly preferably 90% by mass or more, relative to the mass of the thermoplastic resin (D), from the viewpoint of easily enhancing biodegradability. The thermoplastic resin (D) may be produced by a conventional method, or a commercially available product may be used.

[0043] In one embodiment of the present invention, the melt volume rate (MVR) of the thermoplastic resin (D) measured under conditions of 190°C and 5 kgf is preferably 0.5 mL / 10 min or more, more preferably 1.0 mL / 10 min or more, even more preferably 1.5 mL / 10 min or more, and preferably 30 mL / 10 min or less, more preferably 20 mL / 10 min or less, and even more preferably 10 mL / 10 min or less. Having the MVR of the thermoplastic resin (D) within the above ranges facilitates improving stretchability, impact strength, and recyclability. The MFR and MVR of the thermoplastic resin (D) can be adjusted, for example, by appropriately changing the molecular weight, the type and content of the structural units, etc.

[0044] In one embodiment of the present invention, the melt flow rate (MFR) of the thermoplastic resin (D) measured under conditions of 190 to 230°C and 2.16 kgf is preferably 0.1 g / 10 min or more, more preferably 0.5 g / 10 min or more, even more preferably 1.0 g / 10 min or more, and preferably 50 g / 10 min or less, more preferably 30 g / 10 min or less, and even more preferably 20 g / 10 min or less. When the MFR of the thermoplastic resin (D) is within the above range, stretchability, impact strength, and recyclability are likely to be improved. The measurement temperature under the above MFR conditions is, for example, preferably 190°C when the thermoplastic resin is polyethylene, and preferably 230°C when the thermoplastic resin is polypropylene.

[0045] The content of thermoplastic resin (D) is 5 to 80 parts by mass relative to 100 parts by mass of the total of components (A), (B), (C), and (D). If the content of thermoplastic resin (D) is less than 5 parts by mass and more than 80 parts by mass, stretchability, impact strength, adhesive strength, and recyclability tend to decrease. The content of the thermoplastic resin (D) is 5 parts by mass or more, preferably 10 parts by mass or more, more preferably 20 parts by mass or more, even more preferably 30 parts by mass or more, still more preferably 40 parts by mass or more, particularly preferably 50 parts by mass or more, especially more preferably 55 parts by mass or more, and is 80 parts by mass or less, preferably 75 parts by mass or less, more preferably 70 parts by mass or less. When the content of the thermoplastic resin (D) is within the above range, stretchability, impact strength, adhesive strength, and recyclability are likely to be improved.

[0046] <Resin composition> The resin composition of the present invention contains, relative to 100 parts by mass of the total of components (A), (B), (C), and (D), 6 to 45 parts by mass of modified starch (A), 1 to 5 parts by mass of water-soluble polymer (B), 1 to 50 parts by mass of polyol plasticizer (C), and 5 to 80 parts by mass of thermoplastic resin (D), and is represented by the following formula (1): 0<(A) mass / (C) mass<1 (1) Since the resin composition satisfies the above requirements, it is possible to achieve both excellent stretchability and excellent impact strength under low temperature and low humidity conditions. Furthermore, a laminate comprising a layer made of the resin composition can exhibit excellent adhesive strength at the interface with the layer adjacent to the layer. Furthermore, as described below, the resin composition of the present invention also has excellent recyclability. Therefore, the resin composition of the present invention can be suitably used as a material for food packaging, containers, etc.

[0047] In formula (1), if the ratio of the mass of (A) to the mass of (C) is 0 or 1 or more, the stretchability, impact strength, adhesive strength, and recyclability tend to decrease.

[0048] In formula (1), the ratio (mass of (A)) / (mass of (C)) is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.3 or more, and is preferably 0.95 or less, even more preferably 0.90 or less, even more preferably 0.85 or less, and particularly preferably 0.75 or less. When the ratio (mass of (A)) / (mass of (C)) is within the above range, stretchability, impact strength, adhesive strength, and recyclability are likely to be improved.

[0049] The resin composition of the present invention may further contain a fatty acid having 12 to 22 carbon atoms and / or a fatty acid salt thereof. Examples of fatty acids having 12 to 22 carbon atoms and fatty acid salts thereof include stearic acid, calcium stearate, sodium stearate, palmitic acid, lauric acid, myristic acid, linoleic acid, and behenic acid. Among these, from the viewpoint of processability (e.g., stretchability), stearic acid, calcium stearate, and sodium stearate are preferred. The fatty acids having 12 to 22 carbon atoms and fatty acid salts thereof can be used alone or in combination of two or more.

[0050] When the resin composition of the present invention contains a fatty acid having 12 to 22 carbon atoms and / or a fatty acid salt thereof, the content in the resin composition is preferably 0.01 to 3 mass%, more preferably 0.03 to 2 mass%, and even more preferably 0.1 to 1 mass%, relative to the mass of the resin composition. When the content of the fatty acid having 12 to 22 carbon atoms and / or a fatty acid salt thereof is within the above range, it tends to be advantageous in terms of processability.

[0051] The resin composition of the present invention may further contain clay. Examples of clay include synthetic or natural layered silicate clays such as montmorillonite, bentonite, beidellite, mica, hectorite, saponite, nontronite, sauconite, vermiculite, ledikite, magadite, Kenyaite, stevensite, and vulkonskoite. The clays can be used alone or in combination.

[0052] When the resin composition of the present invention contains clay, the content of clay in the resin composition is preferably 0.1 to 5 mass %, more preferably 0.1 to 3 mass %, and even more preferably 0.5 to 2 mass %, relative to the mass of the resin composition. A clay content within the above range tends to be advantageous in terms of transparency and strength.

[0053] The resin composition of the present invention may contain a plasticizer (E) other than the polyol plasticizer (C). Examples of the plasticizer (E) include water, glycerol trioleate, epoxidized linseed oil, epoxidized soybean oil, tributyl citrate, acetyltriethyl citrate, glyceryl triacetate, and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate. The plasticizer (E) may be used alone or in combination. Among these plasticizers (E), water is preferred from the viewpoint of obtaining good film-forming properties and coatability.

[0054] The water content (moisture content) in the resin composition is preferably 3 to 20 mass %, more preferably 4 to 18 mass %, and even more preferably 7 to 15 mass %, relative to the mass of the resin composition, from the viewpoint of easily improving the film-forming properties of the resin composition. The water content can be determined, for example, by measuring at 130°C for 60 minutes using a heat-drying moisture meter.

[0055] The resin composition of the present invention may further contain additives, such as fillers, processing stabilizers, weather resistance stabilizers, colorants, ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, flame retardants, other thermoplastic resins, lubricants, fragrances, antifoaming agents, deodorizers, extenders, release agents, mold release agents, reinforcing agents, crosslinking agents, mildew inhibitors, preservatives, and crystallization rate retarders, as needed.

[0056] In the resin composition of the present invention, the total content of the modified starch (A), the water-soluble polymer (B), the polyol plasticizer (C), and the thermoplastic resin (D) is preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, and even more preferably 90% by mass or more, and is preferably 100% by mass or less, based on the mass of the resin composition. When the total content of components (A), (B), (C), and (D) is within the above range, stretchability, impact strength, adhesive strength, and recyclability are likely to be improved.

[0057] The resin composition of the present invention may be in the form of, for example, pellets, a film, or a sheet. When the resin composition of the present invention is used as a film or sheet, the thickness of the film is generally 5 to 100 μm, and the thickness of the sheet is generally 100 μm to 1000 μm. The film or sheet may be single-layered or multi-layered. In this specification, the term "sheet" can be substituted for "film," and vice versa.

[0058] The stretchability of the resin composition of the present invention increases with increasing strain at break, and can therefore be evaluated by measuring the strain at break. The strain at break of the resin composition is preferably 170% or more, more preferably 250% or more, even more preferably 300% or more, even more preferably 400% or more, particularly preferably 480% or more, and particularly preferably 600% or more. When the strain at break is equal to or greater than the lower limit, the composition has excellent stretchability. The upper limit of the strain at break is usually 1500% or less. The strain at break can be measured using a tensile tester, for example, by the method described in the Examples.

[0059] The resin composition of the present invention exhibits excellent impact strength even when exposed to low temperature and low humidity (e.g., 0°C, 10% RH) for a long period of time (e.g., 2 weeks). The impact strength of a film or sheet made of the resin composition of the present invention after conditioning at 0°C and 10% RH for 2 weeks is preferably 2.5 mN / μm or more, more preferably 3.0 mN / μm or more, even more preferably 4.5 mN / μm or more, even more preferably 6.0 mN / μm or more, and particularly preferably 7.0 mN / μm or more. When the impact strength is above the lower limit, excellent impact strength can be exhibited. The impact strength can be measured using an impact strength tester after conditioning at 0°C and 10% RH for 2 weeks, for example, by the method described in the Examples.

[0060] [Laminate] The present invention encompasses laminates comprising an L1 layer made of the resin composition described above, and an L2 layer different from the L1 layer and containing 50% by mass or more of a thermoplastic resin and / or an L3 layer containing 50% by mass or more of modified starch. The laminate of the present invention has an L1 layer made of the resin composition of the present invention, an L2 layer containing 50% by mass or more of a thermoplastic resin, and an L3 layer containing 50% by mass or more of modified starch. Because the L1 layer is made of the resin composition of the present invention, the L2 layer contains 50% by mass or more of a thermoplastic resin, and the L3 layer contains 50% by mass or more of modified starch, when the L1 layer is adjacent to the L2 layer and / or the L3 layer, the adhesive strength at the interface with the L1 layer is excellent. Therefore, the laminate of the present invention can have sufficient strength without the use of an adhesive.

[0061] In the laminate of the present invention, the L2 layer is a layer different from the L1 layer and contains a thermoplastic resin in an amount of 50% by mass or more relative to the mass of the L2 layer. The thermoplastic resin may be, for example, the thermoplastic resin (D) described above, a conventional thermoplastic resin other than the thermoplastic resin (D), or a combination thereof. However, from the viewpoint of easily improving adhesion to the L1 layer, the thermoplastic resin preferably contains at least the thermoplastic resin (D), more preferably the thermoplastic resin (D), and even more preferably the same thermoplastic resin (D) as the L1 layer. Note that being a layer different from the L1 layer means that the components constituting the L2 layer are not the resin composition of the present invention.

[0062] The L2 layer is a layer different from the L1 layer, and may contain other components as long as it contains 50% by mass or more of a thermoplastic resin. The other components are not particularly limited and include, for example, the additives, conventional resins (e.g., polyolefin resins, polystyrene resins, polyvinyl chloride, polyvinylidene chloride, polyacrylic resins, polyurethane resins, polycarbonate resins, polyamide resins, polyimide resins, etc.), the modified starch (A), the water-soluble polymer (B), the polyol plasticizer (C), the fatty acid having 12 to 22 carbon atoms and / or its fatty acid salt, the clay, the plasticizer (E), etc.

[0063] The content of the thermoplastic resin in the L2 layer is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, still more preferably 90% by mass or more, and preferably 100% by mass or less. When the content of the thermoplastic resin is within the above range, the adhesive strength with the L1 layer is easily increased.

[0064] The L3 layer is a layer containing 50% or more by mass of modified starch. The modified starch may be, for example, the modified starch (A) described above, a conventional modified starch other than the modified starch (A), or a combination thereof. However, from the viewpoint of easily improving adhesion to the L1 layer, it preferably contains at least the modified starch (A), and more preferably the modified starch (A). The L3 layer may contain the other components described above, and from the viewpoint of easily improving adhesion to the L1 layer, it preferably contains a water-soluble polymer (B). When the L3 layer contains the water-soluble polymer (B), the content of the water-soluble polymer (B) is preferably 2% by mass or more, more preferably 5% by mass or more, and preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less, based on the mass of the L3 layer.

[0065] The content of the modified starch in the L3 layer is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, and is preferably 100% by mass or less, and more preferably 98% by mass or less, relative to the mass of the L3 layer. When the content of the modified starch is within the above range, the adhesive strength with the L1 layer and the strength of the laminate are easily increased.

[0066] The laminate of the present invention may contain at least one L1 layer, at least one L2 layer, and / or at least one L3 layer, or may contain at least two of any or all of the layers. When two or more layers are contained, the thickness and composition of each layer may be the same or different.

[0067] In one embodiment of the present invention, from the viewpoint of easily increasing the adhesiveness between the layers and the strength of the laminate, the thickness of at least one L1 layer is preferably 10 to 450 μm, the thickness of at least one L2 layer is preferably 5 to 500 μm, and the thickness of at least one L3 layer is preferably 20 to 800 μm.

[0068] The thickness of at least one L1 layer is more preferably 50 μm or more, even more preferably 100 μm or more, particularly preferably 150 μm or more, and more preferably 450 μm or less, even more preferably 400 μm or less, particularly preferably 350 μm or less. The thickness of at least one L2 layer is more preferably 10 μm or more, even more preferably 20 μm or more, and more preferably 500 μm or less, even more preferably 200 μm or less, particularly preferably 80 μm or less. The thickness of at least one L3 layer is more preferably 50 μm or more, even more preferably 70 μm or more, particularly preferably 200 μm or more, and more preferably 800 μm or less, even more preferably 600 μm or less, particularly preferably 400 μm or less.

[0069] In one embodiment of the present invention, from the viewpoint of easily increasing the adhesiveness between the layers and the strength of the laminate, the total thickness of the L1 layer is preferably 10 to 1000 μm, the total thickness of the L2 layer is preferably 5 to 300 μm, and the total thickness of the L3 layer is preferably 20 to 2000 μm.

[0070] The total thickness of the L1 layer is more preferably 50 μm or more, even more preferably 100 μm or more, particularly preferably 150 μm or more, and more preferably 800 μm or less, even more preferably 700 μm or less. The total thickness of the L2 layer is more preferably 10 μm or more, even more preferably 20 μm or more, and more preferably 1000 μm or less, preferably 500 μm or less, even more preferably 200 μm or less. The total thickness of the L3 layer is more preferably 50 μm or more, even more preferably 70 μm or more, particularly preferably 200 μm or more, and more preferably 1600 μm or less, even more preferably 1200 μm or less, particularly preferably 800 μm or less. The total thickness of the layers refers to the thickness of one layer when there is one layer, and refers to the total thickness of all layers when there are two or more layers. The thickness of each layer can be measured using a microscope, for example, by the method described in the Examples.

[0071] In one embodiment of the present invention, the laminate of the present invention preferably at least partially comprises a layer structure selected from the group consisting of a layer structure having an L3 layer / an L1 layer / an L3 layer in this order, a layer structure having an L2 layer / an L1 layer / an L3 layer in this order, and a layer structure having an L2 layer / an L1 layer / an L2 layer in this order. When the laminate comprises such a layer structure, the L1 layer is adjacent to the L2 layer and / or the L3 layer, which makes it easy to exhibit excellent adhesive strength at the interface between the L1 layer and the L2 layer and at the interface between the L1 layer and the L3 layer, and thus makes it easy to improve the strength of the laminate.

[0072] In one embodiment of the present invention, the adhesive strength at the interface between the L1 layer and the L2 layer is preferably 25 N / 15 mm or more, more preferably 28 N / 15 mm or more, and even more preferably 30 N / 15 mm or more. When the adhesive strength is equal to or greater than the lower limit, excellent adhesiveness is likely to be exhibited. The adhesive strength is usually 100 N / 15 mm or less. The adhesive strength at the interface between the L1 layer and the L3 layer is preferably 15 N / 15 mm or more, more preferably 20 N / 15 mm or more, and even more preferably 25 N / 15 mm or more. When the adhesive strength is equal to or greater than the lower limit, excellent adhesiveness is likely to be exhibited. The adhesive strength is usually 100 N / 15 mm or less. The adhesive strength can be measured by tensile testing at the interface after humidifying the laminate for two weeks under conditions of a temperature of 23°C and a humidity of 50% RH, for example, by the method described in the Examples.

[0073] The laminate of the present invention may include a layer (W) other than the L1, L2, and L3 layers. The layer (W) is not particularly limited and may include, for example, a protective layer, a gas barrier layer, a moisture-proof layer, a light-shielding layer, a printed layer, a reinforcing layer, and an adhesive layer. Examples of materials for forming the other layers include polyethylene, polypropylene, ethylene-vinyl acetate copolymer, EVOH, polyvinyl chloride, polyurethane, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyamides such as nylon, polyacrylonitrile, cellulose or its derivatives, paper, glass, and wood. One or more other layers may be provided, and they may be single-layered or multi-layered. When there are two or more other layers, the thicknesses and materials of the layers may be different or the same.

[0074] The laminate of the present invention is not particularly limited, but examples thereof include a laminate having the following layers in the following order: L2 layer / L1 layer / L2 layer; L3 layer / L1 layer / L3 layer; L3 layer / L1 layer / L2 layer; L2 layer / L3 layer / L1 layer / L3 layer / L2 layer; L2 layer / L1 layer / L3 layer / L1 layer / L2 layer.

[0075] [Method of producing resin composition] The resin composition of the present invention can be produced, for example, by a method including the steps of: (1) mixing at least the modified starch (A), the water-soluble polymer (B), the polyol plasticizer (C), and the thermoplastic resin (D) to obtain a mixture; (2) extruding the mixture; and (3) cooling and drying the extruded mixture.

[0076] Step (1) is a step of mixing at least the modified starch (A), the water-soluble polymer (B), the polyol plasticizer (C), and the thermoplastic resin (D), and optionally other components, such as the fatty acid having 12 to 22 carbon atoms and / or its fatty acid salt, the clay, the plasticizer (E), and the additives, can also be mixed together.

[0077] Step (1) is usually carried out using an extruder. In the extruder, the components are subjected to shear stress by the screw and heated by external heat applied to the barrel to be homogeneously mixed. The components may be introduced directly into the extruder, or the components may be premixed using a mixer or grinder before being introduced into the extruder.

[0078] As the extruder, for example, a twin-screw extruder can be used. The twin-screw extruder may be either co-rotating or counter-rotating. The screw diameter may be, for example, 20 to 150 mm, and the ratio (L / D) of the extruder length (L) to the screw diameter (D) may be, for example, 20 to 50. The screw rotation speed is preferably 80 rpm or higher, more preferably 100 rpm or higher. The extrusion molding pressure is preferably 5 bar (0.5 MPa) or higher, more preferably 10 bar (1.0 MPa) or higher.

[0079] Since the resin composition of the present invention contains a polyol plasticizer, it is not necessary to mix any other plasticizer (E) other than the polyol plasticizer in step (1). However, from the viewpoint of the film-forming properties of the resin composition, a plasticizer (E), preferably water, may be mixed. When a plasticizer (E) is mixed, the content of the plasticizer (E) is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 10% by mass or more, even more preferably 15% by mass or more, particularly preferably 20% by mass or more, and preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less, based on the mass of the mixture. Here, the mass of the mixture refers to the total mass of the mixture including the plasticizer (E). In step (1) of this embodiment, the plasticizer (E) may be introduced at the initial stage of extrusion or before the heating temperature is reached, for example, at a temperature below 100°C. The modified starch (A) is subjected to a cooking treatment using a combination of moisture, heat, and shear stress, resulting in gelatinization (gelation). Furthermore, by separately introducing a plasticizer (E), preferably water, the water-soluble polymer such as the water-soluble polymer (B) can be dissolved, the resin composition can be softened, and the modulus and brittleness can be reduced.

[0080] In step (1), the cooking treatment is preferably carried out by heating to a temperature of more than 100°C and not more than 300°C, more preferably from 150°C to 250°C. Here, the cooking treatment is a treatment for crushing and gelling starch granules. Heating can be carried out by applying heat externally to the barrels of the extruder. By applying a temperature that changes stepwise to each barrel, heating to the desired temperature is possible. Cooking at a temperature above 180°C is advantageous in terms of processability.

[0081] Venting the air from the barrel prevents foaming and removes moisture. The residence time in the extruder can be set according to the temperature profile and screw speed, and is preferably 1 to 2.5 minutes.

[0082] In step (2) of extruding the mixture, the molten mixture that has been forced through the extruder while being melt-kneaded is extruded through a die at a temperature of preferably 85 to 300°C, more preferably 90 to 250°C.

[0083] In step (3) of cooling and drying the extruded mixture (melt), the extruded mixture (melt) can be formed into a film or strand, which can then be cooled and dried.

[0084] When the mixture is extruded into a film, it can be cooled and dried while being extruded through a film-forming die and then taken up by a take-up roller. It is preferable to cool the mixture between the die and the roller to prevent it from sticking to the roller. A forming roll may be installed between the die and the roller. The forming roll may be made of, for example, rubber, resin, or metal. For drying, the roll may be heated, and dehumidified air may be supplied during the take-up. In the case of the blown tube method, the dehumidified air can be used to expand the film as it exits the die. Talc can also be entrained in the air flow to prevent the film from blocking.

[0085] When the mixture is extruded into strands, it can be extruded through a strand nozzle with multiple holes and cut with a rotary cutter to form pellets. To prevent the pellets from sticking together, vibration can be applied periodically or constantly, and moisture in the pellets can be removed using hot air, dehumidified air, or an infrared heater.

[0086] (manufactured from recycled materials) The resin composition of the present invention has excellent recyclability. In this specification, "recyclability" refers to the property of being able to recycle the material (X1) containing components (A) and (B) constituting the resin composition, and optionally components (C) and / or (D), to form the resin composition of the present invention. In particular, a preferred embodiment is one in which a layer made of material (X1) or a laminate containing such a layer is reused to form the resin composition of the present invention. Here, material (X1) is intended to encompass not only cases in which it satisfies the composition of the resin composition of the present invention, but also cases in which it does not satisfy the composition.

[0087] The resin composition of the present invention has excellent recyclability, and therefore, even when formed by reusing the material (X1), the resulting laminate has excellent stretchability, impact strength under low temperature and low humidity conditions, and adhesive strength. In addition, the resin composition of the present invention can be recycled repeatedly.

[0088] When the resin composition of the present invention is formed by reusing the material (X1), step (1) in the method for producing the resin composition preferably includes a process (also referred to as process (Z)) of mixing the material (X1) with a material (X2) containing a polyol plasticizer (C) and / or a thermoplastic resin (D). In process (Z), the polyol plasticizer (C) and / or a thermoplastic resin (D), preferably at least the polyol plasticizer (C), is added to and mixed with the material (X2), which facilitates the formation of the resin composition of the present invention without impairing the effects of the present invention (e.g., stretchability, impact strength, adhesive strength).

[0089] The form of material (X1) is not particularly limited, and examples thereof include a monolayer or a laminate, preferably a monolayer sheet or a multilayer sheet. When material (X1) is a laminate, the components constituting material (X1) may be contained in the same layer or in different layers. For example, when material (X1) has a three-layer structure containing components (A), (B), and (D), the middle layer may contain components (A) and (B), and the outer layer may contain component (D).

[0090] When the material (X1) is a single-layer sheet or a multi-layer sheet, it is preferable to pulverize the sheet in advance using a pulverizer before mixing in the extruder. The material (X2) may be in the form of a sheet, but from the viewpoint of production efficiency, it is preferably in the form that does not need to be subjected to a pulverizer, such as pellets.

[0091] When the thermoplastic resin (D) is a water-insoluble thermoplastic resin, it has been difficult to recycle materials containing at least modified starch, a water-soluble polymer, and a thermoplastic resin, particularly materials in the form of laminates (e.g., laminates in which the inner layer contains modified starch and a water-soluble polymer and the outer layer contains a thermoplastic resin), because of the poor compatibility between water-soluble polymers and water-insoluble thermoplastic resins. However, the present inventors have unexpectedly found that even such materials can be recycle-ready by adjusting the composition to that of the resin composition of the present invention.

[0092] In the present invention, even if the material (X1) contains a thermoplastic resin (D), it can be recycled without impairing the effects of the present invention. Therefore, in the step (Z), it is more preferable that the material (X1) contains at least the modified starch (A), the water-soluble polymer (B), and the thermoplastic resin (D), and the material (X2) contains at least the polyol plasticizer (C).

[0093] Furthermore, in the present invention, even if the material (X1) is in the form of a laminate that is difficult to mix, it can be recycled without impairing the effects of the present invention, so it is preferable that the material (X1) is a laminate. The laminate may be the laminate of the present invention or a laminate other than the laminate of the present invention, but from the viewpoint of being able to reuse the laminate of the present invention, the laminate of the present invention is preferred.

[0094] When the material (X1) is a laminate, the step (Z) is preferably a step of melt-kneading the laminated material (X1) with the material (X2), and more preferably a step of melt-kneading the pre-pulverized laminated material (X1) with the material (X2) using an extruder as described above.

[0095] An example of a combination of material (X1) and material (X2) is shown below. In the following embodiment, both material (X1) and material (X2) may contain components other than (A), (B), (C), and (D). (1) Material (X1); (A) (B), Material (X2); (C) (D) (2) Material (X1); (A) (B) (C), Material (X2); (D) (3) Material (X1); (A) (B) (C), Material (X2); (C) (D) (4) Material (X1); (A) (B) (D), Material (X2); (C) (5) Material (X1); (A) (B) (D), Material (X2); (C) (D) (6) Material (X1); (A) (B) (C) (D), Material (X2); (C) (7) Material (X1); (A) (B) (C) (D), Material (X2); (D) (8) Material (X1); (A) (B) (C) (D), Material (X2); (C) (D).

[0096] When the material (X1) is a laminate, the laminate is not particularly limited, and examples thereof include the laminate of the present invention described in the section [Laminate], as well as a laminate having layers in the order of L2 layer / L3 layer / L2 layer.

[0097] [Method of manufacturing laminate] The method for producing the laminate of the present invention is not particularly limited, and may be, for example, a coextrusion molding method; a method in which a composition extruded from an extruder is coated on a layer transported by a take-up machine; or a combination of these methods.

[0098] In one embodiment of the present invention, the method for producing the laminate of the present invention can suitably use a step of co-extrusion molding the L1 layer and other layers including the L2 layer and / or the L3 layer, which may include the layer (W).

[0099] Examples of extruders used in coextrusion include single-screw extruders and twin-screw extruders. The extruder has a screw diameter of, for example, 15 to 150 mm, an L / D ratio (the ratio of the extruder length (L) to the screw diameter (D)) of, for example, 15 to 50, and a screw rotation speed of preferably 80 rpm or more, more preferably 100 rpm or more. The cylinder temperature in the extruder and the die outlet temperature may be, for example, 80 to 250°C, and preferably 90 to 200°C.

[0100] In one embodiment of the present invention, the method for producing a laminate of the present invention preferably includes a coextrusion molding step and a step of coating the coextruded composition onto a layer transported by a take-up machine. When the laminate of the present invention is a laminate having an L2 layer / L1 layer / L3 layer / L1 layer / L2 layer in this order, for example, a resin composition forming the L1 layer and a composition forming the L2 layer are fed into an extruder, whereby these compositions are plasticized and extruded from a multilayer film-forming die outlet. Then, the L3 layer transported by a take-up machine, preferably a roller-type take-up machine, is coated with the coextruded composition from the die outlet, thereby laminating the L1 layer and the L2 layer onto the L3 layer. Furthermore, by similarly coating the opposite side of the L3 layer, a laminate having an L2 layer / L1 layer / L3 layer / L1 layer / L2 layer in this order is obtained. The obtained laminate is transported while being pressed with a pressure roll or the like, and can be wound into a roll by a winder. The laminates according to other embodiments of the present invention can be produced by conventional methods or based on the above-described embodiments, with appropriate modifications depending on the layer structure and composition of the laminate.

[0101] The L1 layer in the laminate of the present invention may be formed from a non-recycled resin composition or a recycled resin composition. Furthermore, by recycling the laminate of the present invention as, for example, material (X1), a new resin composition or laminate can be formed.

[0102] [recycling] One embodiment of the recycling method of the present invention will now be described in more detail. FIG. 1 is a schematic diagram showing a recycling scheme for a laminate according to one embodiment of the present invention. Laminate 1 is a laminate other than that of the present invention, having an L3 layer, an L2 layer, and an L3 layer in this order. When recycling laminate 1, resin composition 2 is formed by, for example, mixing material (X1) that is laminate 1 with material (X2) containing a polyol plasticizer (C) and / or a thermoplastic resin (D). Next, the resulting resin composition 2 is subjected to, for example, co-extrusion molding to form laminate 3 that includes an L1 layer made of resin composition 2. As a result, the L1 layer in laminate 3 becomes a recycled layer (also referred to as a recovered layer). The layer structure of laminate 3 is in the order of L2 layer, L1 layer (recovered layer), L3 layer, L1 layer (recovered layer), and L2 layer. Next, resin composition 4 is formed by, for example, mixing material (X1) that is laminate 3 with material (X2') containing a polyol plasticizer (C) and / or a thermoplastic resin (D). Similarly to the above, the obtained resin composition 4 is co-extruded or the like to form a laminate 5 including an L1' layer (recovery layer) made of the resin composition 4. The layer structure of the laminate 5 is L2 layer / L1' layer (recovery layer) / L3 layer / L1' layer (recovery layer) / L2 layer in this order. In this way, the resin composition or laminate of the present invention can be recycled repeatedly, and even the recycled resin composition and laminate can have excellent stretchability, impact strength, adhesive strength, etc.

[0103] Furthermore, for example, when the sheet-like laminate 1 is molded into a coffee capsule container and used, a large amount of thermoforming burrs (for example, about 50%) remains, but in the present invention, such thermoforming burrs (laminate 1) can be recycled repeatedly, for example, as shown in Fig. 1, thereby reducing the environmental impact. In particular, in the production of food containers or packaging materials, many skeletons, like the thermoforming burrs of the coffee capsule containers described above, are often generated, and therefore the resin composition and laminate of the present invention can be suitably used. [Example]

[0104] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0105] Test Method

[0106] (1) Breaking strain The stretchability of the resin compositions (single-layer sheets) obtained in the examples and comparative examples was evaluated according to the following method. The 250 μm single-layer sheets obtained in the Examples and Comparative Examples were cut into strips 15 mm wide and 10 cm long. The cut samples were then clamped at both ends of the short sides in the chucks of a tensile tester, stretched at a constant speed (500 mm / min), and measured until breakage. The break strain of the single-layer sheet was calculated using the following formula, where the distance between the chucks before stretching was the initial length A0 (mm) and the distance between the chucks at breakage was the break length A1 (mm). Breaking strain (%) = A1 / A0 x 100 Tensile testing machine: Instron "INSTRON3367", load cell 500N The stretchability of the resin composition (single-layer sheet) can be evaluated as good if the strain at break is 170% or more.

[0107] (2) Impact strength The impact strength at low temperature and low humidity of the resin compositions (single layer sheets) obtained in the Examples and Comparative Examples was evaluated according to the following method. The 250 μm single-layer sheets obtained in the Examples and Comparative Examples were cut into squares measuring 10 cm in width and 10 cm in length. The cut samples were then conditioned for two weeks at a temperature of 0°C and a humidity of 10% RH, and then fixed to the sample stage of the impact strength tester described below. The energy required for a pendulum equipped with a 15 kg weight to break the sample was measured, and the impact strength was calculated using the following formula. Impact strength (mN / μm) = energy required to break the sample (kgf cm) × 1000 × 0.098 / sample thickness (μm) Impact strength tester: Toyo Seiki "Film Impact Tester" The impact strength of the resin composition (single layer sheet) can be evaluated as good if it is 2.5 mN / μm or more.

[0108] (3) Adhesive strength The adhesive strength of the laminates (multilayer sheets) obtained in the examples and comparative examples was evaluated according to the following method. The laminates (L2 layer / L1 layer / L3 layer / L1 layer / L2 layer) obtained in the examples and comparative examples were cut into strips 15 mm wide and 10 cm long. The interfaces to be measured were the interface between the L2 layer made of a thermoplastic resin and the L1 layer made of a resin composition (one of the two interfaces), and the interface between the L3 layer containing modified starch and the L1 layer made of a resin composition (one of the two interfaces). The cut samples were conditioned for two weeks at a temperature of 23°C and a humidity of 50%RH, and then the interfaces to be measured were pulled and peeled off under the following conditions using the following device, and the adhesive strength at each interface was measured. Measuring device: Instron "INSTRON3367", load cell maximum load 1kN Measurement conditions: Temperature: 23°C, Humidity: 50% RH, Peeling angle: 180° Adhesive strength (N / 15m) = Energy required to peel the sample (kgf) x 9.8 In addition, the adhesive strength at the interface between the L2 layer and the L1 layer can be evaluated as good if it is 25N / 15mm or more, and the adhesive strength at the interface between the L3 layer and the L1 layer can be evaluated as good if it is 15N / 15mm or more.

[0109] (4) Thickness The thickness of each layer of the single-layer sheet and the multilayer sheet obtained in the examples and comparative examples was measured by cutting out a cross section and using an optical microscope. Cross-sectioning device: Yamato Koki Kogyo Co., Ltd., "Small rotary microtome PR-50" Measuring device: Nikon "ECLIPSE Ci-E"

[0110] (5) Viscosity measurement method for polyvinyl alcohol In accordance with JIS Z 8803 (falling ball viscometer) and JIS K 6726 (polyvinyl alcohol test method), 4% aqueous solutions of polyvinyl alcohol in the examples and comparative examples were prepared, and the viscosity at 20°C was measured using a Hoebler viscometer, and this was taken as the viscosity (20°C) of the 4% aqueous solution of polyvinyl alcohol.

[0111] (6) Materials used <Modified starch (A)> (A-1): ECOFILM (trademark); corn starch modified with propylene oxide, amylose content 70% by mass, manufactured by Ingredion (A-2): National 1658 (trademark); corn starch modified with propylene oxide, amylose content 20% by mass, manufactured by Ingredion

[0112] <Water-soluble polymer (B)> (B-1): ELVANOL (trademark) 71-30; polyvinyl alcohol resin, saponification degree 99 mol% or more, viscosity 27-33 mPa·s (20°C, 4% aqueous solution), manufactured by Kuraray Co., Ltd.

[0113] <Polyol plasticizer (C)> (C-1): Sorbitol SG; sorbitol, manufactured by Bussan Food Science Co., Ltd. (C-2): Xylitol, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. (C-3): Sucrose (Fujifilm Wako Pure Chemical Industries, Ltd.)

[0114] <Thermoplastic resin (D)> (D-1): Ecovio™ F2341; a mixture of PLA and PBAT, MVR (Melt Volume Rate) 2.5-7.5 mL / 10 min (190°C, 5 kg), manufactured by BASF (D-2): ingeo™ 2003D; PLA, MFR (Melt Flow Rate) 6 g / 10 min (210°C, 2.16 kg), manufactured by Nature Works (D-3): SKYGREEN K2012 (trademark); PETG, manufactured by SK Chemicals (D-4): Novatec LD (trademark) LC600A; low-density polyethylene, MFR (Melt Flow Rate) 7 g / 10 min (190 °C, 2.16 kg), manufactured by Japan Polyethylene Co., Ltd. (D-5): Novatec PP (trademark) EA7AD; polypropylene, MFR (Melt Flow Rate) 1.4 g / 10 min (230 °C, 2.16 kg), manufactured by Japan Polypropylene Corporation The thermoplastic resins (D-1) and (D-2) are biodegradable in a biodegradability test in accordance with EN13432.

[0115] Example 1 (Preparation of single layer sheet) A monolayer film containing 67% by mass of modified starch (A-1), 23% by mass of modified starch (A-2), and 10% by mass of water-soluble polymer (B-1) as raw materials was subjected to a grinder ("ultracentrifugal grinder", ZM100, manufactured by Retsch). Hereinafter, modified starch (A) containing 67% by mass of modified starch (A-1) and 23% by mass of modified starch (A-2) will be referred to as modified starch (A'). The average amylose content of modified starch (A') was 58% by mass.

[0116] 15.3 parts by mass of film pieces (containing 90% by mass of modified starch (A') and 10% by mass of water-soluble polymer (B-1)) pulverized in a mill were mixed with 16.7 parts by mass of polyol plasticizer (C-1) and 67.9 parts by mass of thermoplastic resin (D-1) in a twin-screw extruder. The screw diameter, L / D ratio, rotation speed, operating mode, and temperature profile (Table 1) of the twin-screw extruder are shown below, and a schematic diagram of the twin-screw extruder is shown in Figure 2. In Example 1, material (X1) was a monolayer film, and material (X2) was 16.7 parts by mass of polyol plasticizer (C-1) and 67.9 parts by mass of thermoplastic resin (D-1).

[0117] [Table 1] Screw diameter: 27mm L / D ratio: 48 Screw rotation speed: 100 rpm Operation method: Co-rotation (meshing self-wiping) method

[0118] The mixture was fed into the twin-screw extruder via a weight feeder into the barrel at a rate of 4 kg / hour through a hopper at C1. The temperature ranges from C5 to C9 were cooking zones, and complete gelatinization was achieved within these zones to prepare the resin composition. The film-forming die was located from C11 onwards.

[0119] The resin composition was extruded through the film-forming die of the twin-screw extruder, formed into a film using a casting roll, and then taken up to produce a single-layer sheet (L1) made of the resin composition. The single-layer sheet (L1) had a thickness of 250 μm and contained 13.8% by mass of modified starch (A'), 1.5% by mass of water-soluble polymer (B-1), 16.7% by mass of polyol plasticizer (C-1), and 67.9% by mass of thermoplastic resin (D-1).

[0120] (Production of multilayer sheets) Separately, using the twin-screw extruder described above, the following strand die was attached after C11 of the twin-screw extruder, and the components were mixed and kneaded in the same manner as above. The resulting resin composition was extruded from the twin-screw extruder's multi-hole strand nozzle. The resulting strands were cut with a rotary cutter to produce pellets. The composition of the pellets was the same as that of the single-layer sheet (L1). Strand die: 450mm wide coat hanger die Lip opening: 0.2 mm Distance between die and casting roll (air gap): 10 mm

[0121] For the L1 layer, the obtained pellets (containing 13.8% by mass of modified starch (A'), 1.5% by mass of water-soluble polymer (B-1), 16.7% by mass of polyol plasticizer (C-1), and 67.9% by mass of thermoplastic resin (D-1)) were fed into a single-screw extruder (1) shown in Table 2 and extruded through a multi-layer film-forming die. For the L2 layer, the thermoplastic resin (D-1) crushed into pellets was fed into a single-screw extruder (2) shown in Table 3 and extruded through a multi-layer film-forming die. Next, both sides of the sheet (L3 layer, containing 90% by mass of modified starch (A') and 10% by mass of water-soluble polymer (B-1)) conveyed by a roller-type take-up machine were coated with the resin composition to become the L1 layer extruded from the multilayer film-forming die, and then both sides of that were coated with the resin to become the L2 layer extruded from the multilayer film-forming die. The sheet (L3 layer) was immediately pressed with a pressure roll, and then wound into a roll with a winder to obtain a laminate (multilayer sheet). The multilayer sheet had a layer structure consisting of L2 layer [50 μm] / L1 layer [260 μm] / L3 layer [290 μm] / L1 layer [260 μm] / L2 layer [50 μm] in this order. The numbers in parentheses indicate the thickness of each layer.

[0122] Single-screw extruder (1): Extruder manufactured by the Institute of Plastics Engineering (screw diameter 32 mm, L / D ratio = 28) Set temperature: [Table 2] Discharge amount: 2.5kg / hr Distance between die and casting roll (air gap): 150 mm

[0123] Single-screw extruder (2): Toyo Seiki extruder (screw diameter 20 mm, L / D ratio = 20) Set temperature: [Table 3] Discharge amount: 0.5kg / hr Distance between die and casting roll (air gap): 150 mm

[0124] Examples 2 to 8, 11 and 12 (Example 3 is a reference example) , and Comparative Examples 1 to 11> Single-layer sheets (resin compositions) and multilayer sheets (laminates) were obtained in the same manner as in Example 1, except that the contents of modified starch (A) and water-soluble polymer (B), and the types and amounts of polyol plasticizer (B) and thermoplastic resin (D) were adjusted as shown in Table 5. In Examples 8 and 12, the temperature in the twin-screw extruder shown in Table 1 (C5 to C11, adapter, and die) designated as 200°C was changed to 220°C and 230°C, respectively, taking into account the type of thermoplastic resin (D). Furthermore, in Table 5, all starches (A) were modified starches (A'), and all water-soluble polymers (B) were water-soluble polymers (B-1).

[0125] Example 9 (Fabrication of multilayer structure) For the L2 layer, pelletized thermoplastic resin (D-1) was fed into a single-screw extruder (3) shown in Table 4 and extruded through a multilayer film-forming die. Both sides of a sheet (L3 layer, containing 90% by mass of modified starch (A') and 10% by mass of water-soluble polymer (B-1)) transported by a roller-type take-up machine were coated with the resin (L2 layer) extruded from the multilayer film-forming die. The sheet was immediately pressed against the L3 layer using a pressure roll and then wound into a roll using a winder to obtain a multilayer structure. The multilayer structure had a layer structure consisting of an L2 layer [50 μm], an L3 layer [450 μm], and an L2 layer [50 μm] in this order. The numbers in parentheses indicate the thickness of each layer.

[0126] Single-screw extruder (3): Extruder manufactured by the Institute of Plastics Engineering (32 mm diameter, L / D = 28) Set temperature: [Table 4] Discharge amount: 0.5kg / hr Distance between die and casting roll (air gap): 150 mm

[0127] (Recycling of multi-layer structures) The multilayer structure obtained above was pulverized using a pulverizer ("Ultracentrifugal pulverizer," ZM100, manufactured by Retsch). 18.8 parts by mass of the pulverized film pieces [containing 73.6% by mass of starch (A'), 8.2% by mass of water-soluble polymer (B-1), and 18.2% by mass of thermoplastic resin (D-1)] were added with 16.7 parts by mass of polyol plasticizer (C-1) and 64.5 parts by mass of thermoplastic resin (D-1). The mixture was mixed and kneaded in a twin-screw extruder (under the conditions listed in Table 1 in Example 1) to obtain a resin composition with the same composition as in Example 1. Using the resulting resin composition, a single-layer sheet (resin composition) and a multilayer sheet (laminate) were obtained in the same manner as in Example 1. In Example 9, material (X1) was the multilayer structure, and material (X2) consisted of 16.7 parts by mass of polyol plasticizer (C-1) and 64.5 parts by mass of thermoplastic resin (D-1).

[0128] Example 10 (Recycling of laminates) The multilayer sheet (laminate) obtained in Example 1 was pulverized using a pulverizer ("ultracentrifugal pulverizer," ZM100, manufactured by Retsch). 37.7 parts by mass of the pulverized film pieces [containing 36.6% by mass of starch (A'), 4.0% by mass of water-soluble polymer (B-1), 9.5% by mass of polyol plasticizer (C-1), and 49.8% by mass of thermoplastic resin (D-1)] were added with 13.1 parts by mass of polyol plasticizer (C-1) and 49.1 parts by mass of thermoplastic resin (D-1). The mixture was mixed and kneaded in a twin-screw extruder (under the conditions shown in Table 1 in Example 1) to obtain a resin composition with the same composition as in Example 1. Using the resulting resin composition, a single-layer sheet (resin composition) and a multilayer sheet (laminate) were obtained in the same manner as in Example 1. In Example 10, material (X1) is the multilayer sheet (laminate) obtained in Example 1, and material (X2) is 13.1 parts by mass of polyol plasticizer (C-1) and 49.1 parts by mass of thermoplastic resin (D-1).

[0129] Example 13 The multilayer sheet obtained in Example 1 was molded into a coffee capsule container under the following conditions. Equipment: Compressed air vacuum forming machine (FKS-0632-20) Thermoforming temperature: 115℃ Draw ratio: 0.5 Pressure: 0.5 MPa Compression time: 4 seconds

[0130] The single-layer and multilayer sheets obtained in Examples 1 to 12 and Comparative Examples 1 to 11 were used to measure the strain at break, impact strength, and adhesive strength. The results and the acceptable ranges are shown in Table 5. Table 5 also shows the amounts of starch (A) and water-soluble polymer (B) added, the types and amounts of polyol plasticizer (C) and thermoplastic resin (D), and the mass of modified starch (A) / mass of polyol plasticizer (C) (A / C). [Table 5]

[0131] As shown in Table 5, the monolayer sheets obtained in Examples 1 to 12 were confirmed to be good in both stretchability and impact strength under low-temperature, low-humidity conditions. In contrast, the monolayer sheets obtained in Comparative Examples 1 to 11 were confirmed to be poor in both stretchability and impact strength, or either one of them. It was also confirmed that the multilayer sheets obtained in Examples 1 to 12 had good interfacial adhesive strength. Therefore, it was found that the resin composition of the present invention can achieve both excellent stretchability and excellent impact strength under low-temperature, low-humidity conditions, and that laminates including layers made of this resin composition have excellent interfacial adhesive strength. Furthermore, a multilayer structure was used in Example 9, and a laminate of the present invention was used in Example 10 to prepare a resin composition having the same composition as in Example 1, and a single-layer sheet was obtained using the same. The single-layer sheets obtained in Examples 9 and 10 showed favorable evaluation results almost similar to those of Example 1. These results also demonstrated that the resin composition and laminate of the present invention have excellent recyclability. [Explanation of symbols]

[0132] 1, 3, 5... laminate (layer structure), 2, 4... resin composition, 8... twin-screw extruder, 9... hopper, 10... liquid addition nozzle, 11... resin temperature gauge, 12... resin pressure gauge, 13... adapter, 14... die

Claims

1. 6 to 30 parts by weight of modified starch (A), 1 to 5 parts by mass of a water-soluble polymer (B), 1 to 45 parts by weight of a polyol plasticizer (C), and The water-soluble polymer (B) and the thermoplastic resin (D) are contained in an amount of 5 to 80 parts by mass, and the water-soluble polymer (B) and the thermoplastic resin (D) are represented by the following formula (1): 0<mass of (A) / mass of (C)<1 (1) and the total content of (A), (B), (C) and (D) is 100 parts by mass.

2. 2. The resin composition according to claim 1, wherein the total content of the modified starch (A), the water-soluble polymer (B), the polyol plasticizer (C), and the thermoplastic resin (D) is 80 mass% or more relative to the mass of the resin composition.

3. The resin composition according to claim 1 or 2, wherein the modified starch (A) has an average amylose content of 45% by mass or more.

4. 4. The resin composition according to claim 1, wherein the water-soluble polymer (B) is a polyvinyl alcohol-based resin.

5. The resin composition according to any one of claims 1 to 4, wherein the polyol plasticizer (C) comprises at least one selected from the group consisting of sorbitol, maltitol, xylitol, erythritol, sucrose, mannitol, lactitol, arabinose, xylose, fructose, glucose, galactose, ribose, trehalose, and glycerol.

6. The resin composition according to any one of claims 1 to 5, wherein the thermoplastic resin (D) comprises at least one selected from a polyolefin-based resin and a polyester-based resin.

7. The resin composition according to any one of claims 1 to 6, wherein the thermoplastic resin (D) comprises a biodegradable thermoplastic resin that is biodegradable in a biodegradability test in accordance with EN13432.

8. A film or sheet comprising the resin composition according to any one of claims 1 to 7.

9. An L1 layer made of the resin composition according to any one of claims 1 to 7; an L2 layer different from the L1 layer and containing 50% by mass or more of the same thermoplastic resin (D) as the L1 layer, and / or an L3 layer containing 50% by mass or more of modified starch; A laminate comprising:

10. a layer structure having an L3 layer / an L1 layer / an L3 layer in this order; A layer structure having an L2 layer / L1 layer / L3 layer in this order, and A layer structure having an L2 layer / L1 layer / L2 layer in this order. The laminate according to claim 9, which comprises at least a layer structure selected from the group consisting of:

11. 11. The laminate according to claim 9 or 10, wherein the thickness of at least one L1 layer is 10 to 450 μm, the thickness of at least one L2 layer is 5 to 500 μm, and the thickness of at least one L3 layer is 20 to 800 μm.

12. The laminate according to any one of claims 9 to 11, wherein the total thickness of the L1 layers is 10 to 1000 µm, the total thickness of the L2 layers is 5 to 1000 µm, and the total thickness of the L3 layers is 20 to 2000 µm.

13. A material (X1) comprising a modified starch (A) and a water-soluble polymer (B), and optionally a polyol plasticizer (C) and / or a thermoplastic resin (D); a material (X2) containing a polyol plasticizer (C) and / or a thermoplastic resin (D); A method for producing the resin composition according to any one of claims 1 to 7, comprising a step of mixing the above components.

14. 14. The method according to claim 13, wherein in the step, the material (X1) comprises at least a modified starch (A), a water-soluble polymer (B), and a thermoplastic resin (D), and the material (X2) comprises at least a polyol plasticizer (C).

15. The method according to claim 13 or 14, wherein the step is a step of melt-kneading a material (X1) that is a laminate and a material (X2).

16. The method according to claim 15, wherein the laminate is a laminate according to any one of claims 9 to 12.

17. The method for producing a laminate according to any one of claims 9 to 12, comprising a step of co-extruding the L1 layer and other layers including the L2 layer and / or the L3 layer.

18. A container comprising the laminate according to any one of claims 9 to 12.

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