JP2021172824A - Resin composition and method for producing the same - Google Patents

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

The present invention relates to a resin composition used for a food packaging container and a method for producing the same, a film or sheet composed of the resin composition, a laminate containing a layer composed of the resin composition, a method for producing the same, and the laminate. Concerning a container consisting of.

Conventionally, a resin composition containing a modified starch and a water-soluble polymer has excellent biodegradability and is therefore widely used in a container for packaging food (for example, Patent Document 1).

JP 2013-216918

The resin composition used for these food packaging containers is required to have stretchability from the viewpoint of biodegradability, durability under harsh conditions, and thermoformability. However, according to the study of the present inventor, the conventional resin composition may have a reduced impact strength when exposed to low temperature and low humidity, which is a disadvantageous condition for modified starch, for a long period of time, and the impact strength may decrease. On the contrary, it was found that the stretchability and the impact strength under low temperature and low humidity cannot be compatible with each other because the stretchability is lowered even if the stretchability can be ensured.

Therefore, an object of the present invention is a resin composition having excellent stretchability and excellent impact strength even when exposed to low temperature and low humidity for a long time, a method for producing the same, a film or sheet made of the resin composition, and the resin. An object of the present invention is to provide a laminate containing a layer composed of a composition, a method for producing the laminate, and a container composed of the laminate.

As a result of diligent studies to solve the above problems, the present inventor has determined that the resin composition contains modified starch (A), water-soluble polymer (B), polyol plasticizer (C) and thermoplastic resin (D). If it contains 6 to 45 parts by mass, 1 to 5 parts by mass, 1 to 50 parts by mass, and 5 to 80 parts by mass, respectively, and the mass of the polyol plasticizer (C) is larger than the mass of starch (A), the above-mentioned problem. We have found that we can solve the problem and completed the present invention. That is, the present invention includes the following aspects.

[1] 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 the polyol plasticizer (C) and 5 to 80 parts by mass of the thermoplastic resin (D) different from the water-soluble polymer (B).
Including, the following equation (1);
0 <mass of (A) / mass of (C) <1 (1)
The resin composition, wherein the total content of (A), (B), (C) and (D) is 100 parts by mass.
[2] The total content of the modified starch (A), the water-soluble polymer (B), the polyol plasticizer (C) and the thermoplastic resin (D) is 80% by mass or more with respect to the mass of the resin composition. The resin composition according to [1].
[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 polyol plasticizer (C) is at least selected from the group consisting of sorbitol, maltitol, xylitol, erythritol, sucrose, mannitol, lactitol, arabinose, xylose, fructose, glucose, galactose, ribose, trehalose, and glycerol. The resin composition according to any one of [1] to [4], which comprises one.
[6] The resin composition according to any one of [1] to [5], wherein the thermoplastic resin (D) contains at least one selected from a polyolefin resin and a polyester resin.
[7] The resin composition according to any one of [1] to [6], wherein the thermoplastic resin (D) contains a biodegradable thermoplastic resin having biodegradability in a biodegradability test based on EN13432. thing.
[8] A film or sheet comprising the resin composition according to any one of [1] to [7].
[9] The L1 layer composed of the resin composition according to any one of [1] to [7] and
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 consisting of.
[10] A layer structure having an L3 layer / L1 layer / L3 layer in this order.
At least a part of the layer structure selected from the group consisting of a layer structure having L2 layer / L1 layer / L3 layer in this order and a layer structure having L2 layer / L1 layer / L2 layer in this order is included [9]. ] The laminated body described in.
[11] 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, [9] or [ 10].
[12] The total thickness of the L1 layer is 10 to 1000 μm, the total thickness of the L2 layer is 5 to 1000 μm, and the total thickness of the L3 layer is 20 to 2000 μm. The laminate described.
[13] A material (X1) containing 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),
The method for producing a resin composition according to any one of [1] to [7], which comprises a step of mixing.
[14] In the above 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 a polyol plasticizer (C). The method according to [13], which comprises at least.
[15] The method according to [13] or [14], wherein the step is a step of melt-kneading the material (X1) which is a laminated body and the material (X2).
[16] The method according to [15], wherein the laminate is the laminate according to any one of [9] to [12].
[17] The method for producing a laminate according to any one of [9] to [12], which comprises a step of coextruding the L1 layer and another layer including the L2 layer and / or the L3 layer.
[18] A container made of the laminate according to any one of [9] to [12].

The resin composition of the present invention is excellent in stretchability and can have excellent impact strength even when exposed to low temperature and low humidity for a long time. Therefore, it can be suitably used as a material for food packaging and containers.

It is the schematic which shows the scheme of the recycling of the laminated body which concerns on one Embodiment of this invention. It is the schematic of the twin-screw extruder used in an Example.

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

When the present inventor contains the modified starch (A), the water-soluble polymer (B), the polyol plasticizer (C) and the thermoplastic resin (D) in the above proportions, the compatibility is unexpectedly increased. It has been found that this improves the stretchability of the resin composition and also improves the impact strength under low temperature and low humidity. Furthermore, the present inventor has found that the resin composition of the present invention is also excellent in the adhesive strength between layers of the laminate containing the resin composition and the recyclability of the resin composition. In the present specification, the stretchability of the resin composition, the impact strength under low temperature and low humidity, and the recyclability of the resin composition may be simply referred to as stretchability, impact strength, and recyclability, and the layers of the obtained laminate are laminated. The adhesive strength in the above may be simply referred to as the adhesive strength. Further, the modified starch (A) is the component (A) or simply (A), the water-soluble polymer (B) is the component (B) or simply (B), and the polyol plasticizer (C) is the component (C) or simply ( C), the thermoplastic resin (D) may be referred to as a component (D) or simply (D).

<Denatured 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.

Examples of starch include starch derived from cassava, corn, potato, sweet potato, sago, tapioca, great millet, beans, warabi, hass, hiss, wheat, rice, oat barley, arrowroot, pea and the like. Among them, starch derived from corn and cassava is preferable, and starch derived from high amylose corn is more preferable. Starch can be used alone or in combination of two or more.

Examples of the etherified starch include alkyl etherified starch such as methyl etherified starch; carboxyalkyl etherified starch such as carboxymethyl etherified starch; for example, etherification having a hydroxyalkyl group having 2 to 6 carbon atoms. Examples thereof include hydroxyalkyl etherified starch such as starch. Further, allyl etherified starch and the like can also be used.

Examples of the esterified starch include esterified starch having a structural unit derived from a carboxylic acid such as esterified starch having a structural unit derived from acetic acid; and esterified starch having a structural unit derived from maleic acid anhydride, phthalic acid anhydride, for example. Estered starches having structural units derived from dicarboxylic acid anhydrides such as esterified starches having structural units derived from them, esterified starches having structural units derived from octenyl succinic acid anhydrides; for example, nitrate esterified starches, phosphoric acid esters Examples thereof include esterified starch having a structural unit derived from oxo acid such as modified starch and urea phosphate esterified starch. Other examples include xanthate esterified starch, acetoacetic esterified starch and the like.

Examples of the cationized starch include a reaction product of starch and 2-diethylaminoethyl chloride, a reaction product of starch and 2,3-epoxypropyltrimethylammonium chloride, and the like.

Examples of the crosslinked starch include formaldehyde crosslinked starch, epichlorohydrin crosslinked starch, phosphoric acid crosslinked starch, achlorine crosslinked starch and the like.

The modified starch (A) is derived from an esterified starch having a hydroxyalkyl group having 2 to 6 carbon atoms and a dicarboxylic acid anhydride from the viewpoint of easily enhancing stretchability, impact strength, adhesive strength and recyclability. It is preferably at least one selected from the group consisting of esterified starch having a structural unit, and has a structural unit derived from hydroxyethyl etherified starch, hydroxypropyl etherified starch, hydroxybutyl etherified starch, maleic acid anhydride. More preferably, it is at least one selected from the group consisting of esterified starch, esterified starch having a structural unit derived from phthalic acid anhydride and esterified starch having a structural unit derived from octenyl succinic acid anhydride. The modified starch (A) can be used alone or in combination of two or more. In the present specification, the number of carbon atoms described before "starch" is the carbon atom of a group substituted with one hydroxyl group in starch (a group formed by modifying one hydroxyl group in starch). Represents a number. For example, an etherified starch having a hydroxyalkyl group having 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.

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 or butylene oxide. The average number of hydroxy groups used for denaturation is preferably 0.05-2 per glucose unit in starch.

The modified starch (A) has an average amylose content in the modified starch (A) of preferably 45% by mass or more, more preferably 50% by mass or more, still more preferably 55% by mass or more. When the average amylose content is at least the above lower limit, stretchability, impact strength, adhesive strength, recyclability, and biodegradability are likely to be enhanced. The average amylose content in the modified starch (A) is usually 90% by mass or less. In the present specification, the amylose content can be measured by, for example, the iodine coloring method described in "Starch 50 No. 4 158-163 (1998)". The average amylose content indicates the amylose content of the one type of modified starch when one type of modified starch is used, and when two or more types of modified starch are used, the amylose content of two or more types of modified starch is contained. It is a weighted average of the amounts. Therefore, for example, when two or more types of modified starch are used and the average amylose content is 45% by mass or more, the modified starch having an amylose content of less than 45% by mass may be contained.

The modified starch (A) may have a water content of preferably 5 to 15% by mass in the modified starch (A).

As the modified starch (A), commercially available ones can also be used. Examples of typical commercially available products of the modified starch (A) include ECOFILM ™ and National 1658 ™, which are hydroxypropyl etherified starches manufactured by Ingrediоn.

The content of the modified starch (A) is 6 to 45 parts by mass with respect to a total of 100 parts by mass of the components (A), (B), (C) and (D). When 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, still more preferably 9 parts by mass or more, and 45 parts by mass or less, preferably 40 parts by mass or less. , More preferably 35 parts by mass or less, still 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 in the above range, stretchability, impact strength, adhesive strength, and recyclability are likely to be enhanced.

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

The degree of saponification 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 can be easily improved. The degree of saponification is more preferably 85 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more, still more preferably 98 mol% or more. In the present specification, the degree of saponification refers to the mole fraction of the hydroxyl group with respect to the total of the hydroxyl group and the ester group in polyvinyl alcohol.

Polyvinyl alcohol can further contain other monomeric units other than vinyl alcohol units. Examples of other monomer units include monomer units derived from ethylenically unsaturated monomers. Examples of the ethylenically unsaturated monomer include α-olefins such as ethylene, propylene, n-butene, isobutylene, and 1-hexene; allyl acid and a salt thereof; an unsaturated monomer having an allyl ester group; and methacrylic acid. And salts thereof; unsaturated monomers having a methacrylic ester group; acrylamide, N-methylacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide, diacetoneacrylamide, acrylamide propanesulfonic acid and its salts, acrylamidepropyldimethyl Amin and its salts (eg, quaternary salts); methalkylamides, N-methylmethacrylates, N-ethylmethacrylates, methallylamide propanesulfonic acids and salts thereof, methallylamide propyldimethylamines and salts thereof (eg, 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, dodecyl vinyl ether, stearyl vinyl ether, 2,3-diacetoxy-1-vinyloxypropane, etc. Vinyl ethers; Vinyl cyanide such as acrylonitrile and methacrylonitrile; Vinyl halides such as vinyl chloride and vinyl fluoride; Vinylidene halides such as vinylidene chloride and vinylidene fluoride; Allyl acetate, 2,3-diacetoxy- Allyl compounds such as 1-allyloxypropane and allyl chloride; unsaturated dicarboxylic acids such as maleic acid, itaconic acid and fumaric acid and salts or esters thereof; vinylsilyl compounds such as vinyltrimethoxysilane, isopropenyl acetate; vinyl formate, acetic acid Vinyl, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versaticate, vinyl caproate, vinyl carlylate, vinyl laurate, vinyl palmitate, vinyl stearate, vinyl oleate, vinyl benzoate, etc. Vinyl ester monomers are exemplified. The content of the other monomer unit is preferably 10 mol% or less, and more preferably 5 mol% or less.

The method for producing polyvinyl alcohol is not particularly limited. For example, a method of polymerizing a vinyl alcohol monomer and optionally another monomer and saponifying the obtained polymer to convert it into a vinyl alcohol unit can be mentioned. Examples of the polymerization method at the time of polymerization include batch polymerization, semi-batch polymerization, continuous polymerization, semi-continuous polymerization and the like. Examples of the polymerization method include known methods such as a massive polymerization method, a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method. A known method can be applied to the saponification of the polymer. For example, it can be carried out in a state where the polymer is dissolved in alcohol or hydrous alcohol. The alcohol that can be used at this time is preferably a lower alcohol such as methanol or ethanol.

The water-soluble polymer (B) has a viscosity of a 4% aqueous solution measured in accordance with JIS Z 8803 at 20 ° C., preferably 1 mPa · s or more, more preferably 2 mPa · s or more, and further preferably 3 mPa · s or more. It is preferably 45 mPa · s or less, and more preferably 35 mPa · s or less. When the viscosity of the water-soluble polymer (B) is in 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 Examples.

The content of the water-soluble polymer (B) is 1 to 5 parts by mass with respect to 100 parts by mass in total of the components (A), (B), (C) and (D). When the content of the water-soluble polymer (B) is less than 1 part by mass and 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, 5 parts by mass or less, preferably 4.5 parts by mass or less, and more preferably 4.0 parts by mass. Hereinafter, it is more preferably 3.5 parts by mass or less, and even more preferably 3.0 parts by mass or less. When the content of the water-soluble polymer (B) is in the above range, the stretchability and impact strength are likely to be improved.

<Polyplasticizer (C)>
The polyol plasticizer (C) is not particularly limited, but for example, sorbitol, maltitol, xylitol, erythritol, sucrose, mannitol, lactitol, arabinose, xylose, fructose, glucose, galactose, ribose, trehalose, glycerol, ethylene glycol, propylene. Glycol and the like can be mentioned, and these polyol plasticizers (C) can be used alone or in combination of two or more. Among these, from the viewpoint of easily enhancing stretchability, impact strength, and recyclability, from sorbitol, multitor, xylitol, erythritol, sucrose, mannitol, lactitol, arabinose, xylose, fructose, glucose, galactose, ribose, trehalose and glycerol. It is preferable to contain at least one selected from the group consisting of sorbitol, xylitol and sucrose, and more preferably to contain at least one selected from the group consisting of sorbitol, xylitol and sucrose. As the polyol plasticizer, for example, a commercially available product can be used.

The content of the polyol plasticizer (C) is 1 to 50 parts by mass with respect to 100 parts by mass in total of the components (A), (B), (C) and (D). When the content of the polyol plasticizer (C) is less than 1 part by mass and more than 50 parts by mass, 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, still more preferably 15 parts by mass or more, and 50 parts by mass or less, preferably 45 parts by mass. Hereinafter, it is more preferably 40 parts by mass or less, further 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 in the above range, stretchability, impact strength, and recyclability are likely to be improved.

<Thermoplastic resin (D)>
The thermoplastic resin (D) is not particularly limited, but for example, a polyester resin, an olefin resin, a polyvinyl resin, a polyacrylic resin, a polycarbonate resin, a polythiocarbonate resin, a polyacetal resin, or a polyamide resin. , Polyphenylene ether-based resin, polysulfone-based resin, polyphenylene sulfide-based resin, polyimide-based resin, polyether ketone-based resin, thermoplastic elastomer and the like. These thermoplastic resins (D) can be used alone or in combination of two or more. Among these, the thermoplastic resin (D) preferably contains at least one selected from a polyolefin-based resin and a polyester-based resin from the viewpoint of easily enhancing stretchability, impact strength, adhesive strength, and recyclability. Further, in one embodiment of the present invention, the thermoplastic resin (D) is preferably a water-insoluble resin.

Examples of the polyolefin-based resin include chain polyolefin-based resins such as polyethylene, polypropylene, and polymethylpentene, and cyclic polyolefin-based resins such as cyclopentadiene and norbornene. Among these, stretchability, impact strength, adhesive strength, and adhesive strength, and From the viewpoint of easily enhancing recyclability, a chain polyolefin resin is preferable, and polyethylene (for example, low density polyethylene etc.), polypropylene and the like are more preferable. Polyolefin-based resins can be used alone or in combination of two or more.

Polyethylene indicates a polymer whose main component is an ethylene-derived structural unit, and polypropylene indicates a polymer whose main component is a propylene-derived structural unit. Polyethylene and polypropylene can each further contain other structural units other than the above-mentioned structural units. Examples of other constituent units include the above-mentioned ethylenically unsaturated monomers other than ethylene or propylene. The content of the other monomer unit is preferably 10 mol% or less, and more preferably 5 mol% or less. As the polyethylene or polypropylene, for example, commercially available ones can be used.

The polyester resin represents a polymer having an ester bond as a main bond in the main chain, and has, for example, a constituent unit derived from a dicarboxylic acid and a constituent unit derived from a diol, or a constituent unit derived from a hydroxycarboxylic acid. Show things. When a polyester resin is used as the thermoplastic resin (D), the resin composition of the present invention tends to increase stretchability, impact strength, adhesive strength and biodegradability, and is particularly excellent in biodegradability and adhesive strength.
In the present specification, the "constituent unit of origin" may be simply referred to as "unit". For example, the structural unit derived from dicarboxylic acid is a dicarboxylic acid unit, the structural unit derived from diol is a diol unit, and the constitution derived from hydroxycarboxylic acid. The unit is called a hydroxycarboxylic acid unit.

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; cyclohexanedicarboxylic acid. Alicyclic dicarboxylic acids such as acids, norbornenedicarboxylic acids and tricyclodecanedicarboxylic acids; terephthalic acid, isophthalic acid, phthalic acid, biphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenylketonedicarboxylic acid, sodium sulfoisophthalate. , 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, aromatic dicarboxylic acid such as 2,7-naphthalenedicarboxylic acid; and ester-forming derivatives thereof. Among these, an aliphatic dicarboxylic acid or an aromatic dicarboxylic acid is preferable, an aromatic dicarboxylic acid is more preferable, and a terephthalic acid is further preferable, from the viewpoint of easily increasing the adhesive strength and recyclability. Dicarboxylic acids can be used alone or in combination of two or more. When the polyester resin contains an aromatic dicarboxylic acid unit, the content of the aromatic dicarboxylic acid unit is preferably 50 mol% or more, preferably 70 mol% or more, based on the total molar amount of all the constituent units derived from the dicarboxylic acid. More preferably, 90 mol% or more is further preferable, and 95 mol% or more is particularly preferable.

When the thermoplastic resin (D) is a polyester resin, examples of the diol constituting the diol unit include ethylene glycol, trimethylene glycol, butylene glycol (tetramethylene glycol), hexamethylene glycol, neopentyl glycol, and methylpentane. Aliper diols such as diols and diethylene glycols; cyclohexanedimethanol (eg 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol), norbornenedimethanol, tricyclodecanedimethanol and the like. Alicyclic diols; examples include aromatic diols such as bisphenol compounds and hydroquinone compounds. Among these, aliphatic diols are preferable, ethylene glycol, trimethylene glycol and butylene glycol are preferable, and butylene glycol is more preferable, from the viewpoint of easily increasing the adhesive strength and recyclability. The diol can be used alone or in combination of two or more. When the polyester resin contains a diol unit, the content of the aliphatic diol unit is preferably 50 mol% or more, more preferably 70 mol% or more, and more preferably 90 mol, based on the total molar amount of all the constituent units derived from the diol. % Or more is more preferable, and 95 mol% or more is particularly preferable.

In one embodiment of the present invention, when the polyester resin contains a dicarboxylic acid unit and a diol unit, the ratio of the dicarboxylic acid unit to the diol unit is preferably 10: 1 to 1:10, more preferably 5: 1 to 1. It is 1: 5, more preferably 2: 1 to 1: 2, and particularly preferably 1: 1.

When the thermoplastic resin (D) is a polyester resin, examples of the hydroxycarboxylic acid constituting the hydroxycarboxylic acid unit include 10-hydroxyoctadecanoic acid, lactic acid, hydroxyacrylic acid, and 2-hydroxy-2-methylpropionic acid. , An aliphatic hydroxycarboxylic acid such as hydroxybutyric acid; an alicyclic hydroxycarboxylic acid such as hydroxymethylcyclohexanecarboxylic acid, hydroxymethylnorbornenecarboxylic acid, and hydroxymethyltricyclodecanecarboxylic acid; , 3- (Hydroxyphenyl) propionic acid, hydroxyphenylacetic acid, aromatic hydroxycarboxylic acids such as 3-hydroxy-3-phenylpropionic acid; and ester-forming derivatives thereof. Among these, an aliphatic hydroxycarboxylic acid is preferable, lactic acid and hydroxybutyric acid are more preferable, and lactic acid is further preferable, from the viewpoint of easily increasing the adhesive strength and recyclability. These hydroxycarboxylic acids can be used alone or in combination of two or more.

The polyester resin may have the dicarboxylic acid unit and the diol unit, may have the hydroxycarboxylic acid unit, or may have a combination of these constituent units. Further, the polyester resin may contain a constituent unit other than the dicarboxylic acid unit, the diol unit and the hydroxycarboxylic acid unit as long as the effect of the present invention is not impaired.

In one embodiment of the present invention, the polyester resin is 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. PBAT, PLA, PETG, or a mixture thereof is preferable, and PBAT, PLA, or a mixture thereof is more preferable, from the viewpoint of easily increasing the adhesive strength and recyclability.

In one embodiment of the present invention, the thermoplastic resin (D) preferably contains a biodegradable thermoplastic resin having biodegradability and a biodegradable polyester-based resin in a biodegradability test based on EN13432. 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 based on the mass of the thermoplastic resin (D) from the viewpoint of easily increasing the biodegradability. It is preferably 30% by mass or more, more preferably 50% by mass or more, still more preferably 70% by mass or more, and particularly preferably 90% by mass or more.
The thermoplastic resin (D) may be produced by a conventional method or a commercially available product may be used.

In one embodiment of the present invention, the melt volume rate (MVR) of the thermoplastic resin (D) measured under the conditions of 190 ° C. and 5 kgf is preferably 0.5 mL / 10 minutes or more, more preferably 1.0 mL / 10. Minutes or more, more preferably 1.5 mL / 10 minutes or more, preferably 30 mL / 10 minutes or less, more preferably 20 mL / 10 minutes or less, still more preferably 10 mL / 10 minutes or less. When the MVR of the thermoplastic resin (D) is in the above range, stretchability, impact strength, and recyclability can be easily improved. The MFR and MVR of the thermoplastic resin (D) can be adjusted by appropriately changing, for example, the molecular weight, the type of the structural unit, and the content thereof.

In one embodiment of the present invention, the melt flow rate (MFR) of the thermoplastic resin (D) measured under the conditions of 190 to 230 ° C. and 2.16 kgf is preferably 0.1 g / 10 minutes or more, more preferably 0. It is .5 g / 10 minutes or more, more preferably 1.0 g / 10 minutes or more, preferably 50 g / 10 minutes or less, more preferably 30 g / 10 minutes or less, still more preferably 20 g / 10 minutes or less. When the MFR of the thermoplastic resin (D) is in the above range, stretchability, impact strength, and recyclability can be easily 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 it is polypropylene.

The content of the thermoplastic resin (D) is 5 to 80 parts by mass with respect to 100 parts by mass in total of the components (A), (B), (C) and (D). When the content of the thermoplastic resin (D) is less than 5 parts by mass and more than 80 parts by mass, the 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, still more preferably 30 parts by mass or more, still more preferably 40 parts by mass or more, particularly preferably. It is 50 parts by mass or more, more preferably 55 parts by mass or more, 80 parts by mass or less, preferably 75 parts by mass or less, and more preferably 70 parts by mass or less. When the content of the thermoplastic resin (D) is in the above range, stretchability, impact strength, adhesive strength, and recyclability are likely to be improved.

<Resin composition>
The resin composition of the present invention contains 6 to 45 parts by mass of the modified starch (A) and 1 to 5 parts by mass with respect to 100 parts by mass of the total of the components (A), (B), (C) and (D). The water-soluble polymer (B), 1 to 50 parts by mass of the polyol plasticizer (C), and 5 to 80 parts by mass of the thermoplastic resin (D) are contained in the following formula (1);
0 <mass of (A) / mass of (C) <1 (1)
In order to satisfy the above conditions, both excellent stretchability and excellent impact strength under low temperature and low humidity can be achieved. In addition, the laminate containing the layer made of the resin composition can exhibit excellent adhesive strength at the interface with the layer adjacent to the layer. Further, as described later, 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, and the like.

In the formula (1), when the mass of (A) / the mass of (C) is 0 and 1 or more, the stretchability, impact strength, adhesive strength, and recyclability tend to decrease.

In the formula (1), the mass of (A) / the mass of (C) is preferably 0.1 or more, more preferably 0.2 or more, still more preferably 0.3 or more, and preferably 0.95 or less. , More preferably 0.90 or less, even more preferably 0.85 or less, and particularly preferably 0.75 or less. When the mass of (A) / the mass of (C) is in the above range, stretchability, impact strength, adhesive strength, and recyclability can be easily improved.

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, stearic acid, calcium stearate, and sodium stearate are preferable from the viewpoint of processability (for example, stretchability). Fatty acids having 12 to 22 carbon atoms and fatty acid salts thereof can be used alone or in combination of two or more.

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. It is 01 to 3% by mass, more preferably 0.03 to 2% by mass, and further preferably 0.1 to 1% by mass. When the content of the fatty acid having 12 to 22 carbon atoms and / or the fatty acid salt thereof is in the above range, it tends to be advantageous in terms of processability.

The resin composition of the present invention may further contain clay. Clays include synthetic or natural layered silicate clays such as montmorillonite, bentonite, byderite, mica, hectorite, saponite, nontronite, saponite, vermiculite, lady kite, magadite, kenyaite, stephensite, vorcons. Examples include koito. Clay can be used alone or in combination of two or more.

When the resin composition of the present invention contains clay, the content in the resin composition is preferably 0.1 to 5% by mass, more preferably 0.1 to 3% by mass, based on the mass of the resin composition. %, More preferably 0.5 to 2% by mass. When the clay content is in the above range, it tends to be advantageous in terms of transparency and strength.

The resin composition of the present invention can 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, 2,2,4-trimethyl-1,3. -Pentanediol diisobutyrate can be mentioned. The plasticizer (E) can be used alone or in combination of two or more. Among these plasticizers (E), water is preferable from the viewpoint of obtaining good film-forming property and coatability.

The water content (water content) in the resin composition is preferably 3 to 20% by mass, more preferably 4 to 18% by mass, based on the mass of the resin composition, from the viewpoint of easily enhancing the film-forming property of the resin composition. %, More preferably 7 to 15% by mass. The water content can be determined by measuring at 130 ° C. for 60 minutes using, for example, a heat-drying moisture meter.

The resin composition of the present invention can be used as a filler, a processing stabilizer, a weathering stabilizer, a colorant, an ultraviolet absorber, a light stabilizer, an antioxidant, an antistatic agent, a flame retardant, and other heats, if necessary. Additives such as thermoplastic resins, lubricants, fragrances, defoaming agents, deodorants, bulking agents, release agents, mold release agents, reinforcing agents, cross-linking agents, mold retardants, preservatives, and crystallization rate retarders. Can include.

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 based on the mass of the resin composition. It is preferably 60% by mass or more, more preferably 80% by mass or more, still more preferably 85% by mass or more, still more preferably 90% by mass or more, and preferably 100% by mass or less. When the total content of the components (A), (B), (C) and (D) is within the above range, stretchability, impact strength, adhesive strength and recyclability are likely to be enhanced.

The resin composition of the present invention may be in the form of, for example, pellets and a film or sheet. When the resin composition of the present invention is used as a film or a 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. Further, the film or sheet may be a single layer or a multilayer. In the present specification, the term "sheet" can be substituted for "film", and the term "film" can be substituted for "sheet".

Since the stretchability of the resin composition of the present invention increases as the breaking point strain increases, it can be evaluated by measuring the breaking point strain. The breaking point strain of the resin composition is preferably 170% or more, more preferably 250% or more, still more preferably 300% or more, still more preferably 400% or more, particularly preferably 480% or more, and particularly more preferably 600. % Or more. When the breaking point strain is at least the above lower limit, the stretchability is excellent. The upper limit of breaking point strain is usually 1500% or less. The breaking point strain can be measured using a tensile tester, for example, by the method described in Examples.

The resin composition of the present invention has excellent impact strength even when exposed to low temperature and low humidity (for example, 0 ° C., humidity 10% RH) for a long time (for example, 2 weeks). The impact strength of the film or sheet made of the resin composition of the present invention after adjusting the humidity 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. , 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 equal to or higher than the above lower limit, excellent impact strength can be exhibited. The impact strength can be measured using an impact strength tester after adjusting the humidity for 2 weeks in an environment of a temperature of 0 ° C. and a humidity of 10% RH, and can be measured by, for example, the method described in Examples.

[Laminate]
The present invention includes an L1 layer made of the resin composition, 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. Includes laminate. In the laminate of the present invention, the L1 layer comprises the resin composition of the present invention, the L2 layer contains 50% by mass or more of the thermoplastic resin, and the L3 layer contains 50% by mass or more of the modified starch. Therefore, the L1 layer and the L2 layer And / or when the L3 layers are adjacent to each other, the adhesive strength at the interface with the L1 layer is excellent. Therefore, the laminate of the present invention can have sufficient strength without using an adhesive.

In the laminated body of the present invention, the L2 layer is a layer different from the L1 layer, and is a layer containing 50% by mass or more of the thermoplastic resin with respect to the mass of the L2 layer. The thermoplastic resin may be, for example, the thermoplastic resin (D), a conventional thermoplastic resin other than the thermoplastic resin (D), or a combination thereof, but with the L1 layer. From the viewpoint of easily enhancing the adhesiveness of the resin, the thermoplastic resin preferably contains at least the thermoplastic resin (D), more preferably the thermoplastic resin (D), and is the same thermoplastic resin (D) as the L1 layer. ) Is more preferable. The layer different from the L1 layer means that the component constituting the L2 layer is not the resin composition of the present invention.

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 the thermoplastic resin. The other components are not particularly limited, and are, for example, the above-mentioned additives, conventional resins (for example, polyolefin resins, polystyrene resins, polyvinyl chloride, polyvinylidene chloride, polyacrylic resins, polyurethane resins, polycarbonate resins). Resin, polyamide resin, polyimide resin, 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 Examples thereof include fatty acid salts, the clay, and the plasticizer (E).

The content of the thermoplastic resin contained in the L2 layer is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, still more preferably 90% by mass or more, and preferably 100% by mass. It is mass% or less. When the content of the thermoplastic resin is in the above range, it is easy to increase the adhesive strength with the L1 layer.

The L3 layer is a layer containing 50% by mass or more of modified starch. The modified starch may be, for example, the modified starch (A), a conventional modified starch other than the modified starch (A), or a combination thereof, but has an adhesiveness to the L1 layer. From the viewpoint of easy enhancement, it is preferable to contain at least modified starch (A), and more preferably modified starch (A). The L3 layer may contain the other components, and preferably contains a water-soluble polymer (B) from the viewpoint of easily enhancing the adhesiveness with the L1 layer. 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, based on the mass of the L3 layer. It is preferably 40% by mass or less, more preferably 30% by mass or less, and further preferably 20% by mass or less.

The content of the modified starch contained in the L3 layer is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and preferably 100% by mass with respect to the mass of the L3 layer. Hereinafter, it is more preferably 98% by mass or less. When the content of the modified starch is in the above range, it is easy to increase the adhesive strength with the L1 layer and the strength of the laminate.

The laminate of the present invention may contain one or more L1 layers, L2 layers and / or L3 layers, respectively, and may include two or more layers of any one or all of them. When two or more layers are included, the thickness and composition of each layer may be the same or different.

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

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

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

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

In one embodiment of the present invention, the laminate of the present invention has a layer structure having L3 layer / L1 layer / L3 layer in this order, a layer structure having L2 layer / L1 layer / L3 layer in this order, and L2 layer / L1. It is preferable that at least a part of the layer structure is selected from the group consisting of layers having layers / L2 layers in this order. Including such a layer structure, since the L1 layer and the L2 layer and / or the L3 layer are adjacent to each other, excellent adhesive strength is obtained at the interface between the L1 layer and the L2 layer and the interface between the L1 layer and the L3 layer. It is easy to develop, which makes it easy to improve the strength of the laminate.

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, still more preferably 30 N / 15 mm or more. When the adhesive strength is at least the above 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 further preferably 25 N / 15 mm or more. When the adhesive strength is at least the above 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 adjusting the humidity of the laminate under the conditions of a temperature of 23 ° C. and a humidity of 50% RH for 2 weeks and then pulling the interface with a tensile tester. For example, the adhesive strength can be measured by the method described in Examples.

The laminated body of the present invention may include a layer (W) other than the L1 layer, the L2 layer and the L3 layer. The layer (W) is not particularly limited, and examples thereof include a protective layer, a gas barrier layer, a moisture-proof layer, a light-shielding layer, a printing layer, a reinforcing layer, and an adhesive layer. Examples of the material forming the other layer include polyethylene, polypropylene, ethylene-vinyl acetate copolymer, EVOH, polyvinyl chloride, polyurethane, polyethylene terephthalate, polybutylene terephthalate, polyester such as polyethylene naphthalate, nylon and the like. Polyamide, polyacrylonitrile, cellulose or derivatives thereof, paper, glass, wood and the like can be mentioned. The other layers may be provided in one or more layers, and may be a single layer or multiple layers. When the other layers are two or more layers, the thickness and material of each layer may be different or the same.

The laminate of the present invention is not particularly limited, and examples thereof include a laminate having each layer 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.

[Manufacturing method of resin composition]
The resin composition of the present invention is obtained, for example, by 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. It can be produced by a method including a step (1), a step (2) of extruding the mixture, and a step (3) of cooling and drying the extruded mixture.

The step (1) is at least a step of mixing the modified starch (A), the water-soluble polymer (B), the polyol plasticizer (C), and the thermoplastic resin (D), and optionally other steps. Ingredients such as the fatty acid having 12 to 22 carbon atoms and / or a fatty acid salt thereof, the clay, the plasticizer (E), and the additive can be mixed together.

Step (1) is usually performed using an extruder. In the extruder, shear stress is applied to each component by a screw, and the components are uniformly mixed while being heated by applying external heat to the barrel. Each component may be introduced directly into the extruder, or each component may be premixed using a mixer or a crusher and introduced into the extruder.

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

Since the resin composition of the present invention contains a polyol plasticizer, it is not necessary to mix a plasticizer (E) other than the polyol plasticizer in step (1). From the viewpoint, the plasticizer (E), preferably water, may be mixed. When the 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, still more preferably 10% by mass, based on the mass of the mixture. The above is even more preferably 15% by mass or more, particularly preferably 20% by mass or more, preferably 50% by mass or less, more preferably 45% by mass or less, still more preferably 40% by mass or less. Here, the mass of the mixture indicates the total mass of the mixture containing the plasticizer (E). In step (1) of such an embodiment, the plasticizer (E) may be introduced at the initial stage of extrusion, and the plasticizer (E) may be introduced before reaching the heating temperature, for example, at 100 ° C. or lower. May be good. The modified starch (A) can be made into gelatin (gel) by being cooked by a combination of moisture, heat and shear stress. Further, 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.

In step (1), the cooking process is carried out by heating to a temperature of preferably more than 100 ° C. and 300 ° C. or lower, more preferably 150 ° C. or higher and 250 ° C. or lower. Here, the cooking treatment is a treatment in which starch granules are crushed and gelled. Heating can be performed by applying heat to the barrel of the extruder from the outside. Each barrel can be heated to the desired temperature by applying a stepwise temperature change. When the cooking process is performed at a temperature of more than 180 ° C., it is advantageous in terms of workability.

By exhausting from the barrel, foaming can be prevented and water can be removed. The residence time in the extruder can be set according to the temperature profile and the screw speed, and is preferably 1 to 2.5 minutes.

In the step (2) of extruding the mixture, the molten mixture that has been pushed through the extruder while being melt-kneaded is extruded from the die. The temperature of the die is preferably 85 to 300 ° C, more preferably 90 to 250 ° C.

In the step (3) of cooling and drying the extruded mixture (melt), the extruded mixture (melt) can be cooled and dried in the form of a film or a strand.

When the mixture is extruded into a film, the mixture can be extruded from a film forming die and then cooled and dried while being wound by a take-up roller. It is preferable to cool between the die and the roller so as to prevent the mixture from adhering to the roller. A molding roll may be installed between the die and the roller. The material of the molding roll is, for example, rubber, resin, or metal. For drying, the rolls may be warmed or supplied with dehumidified air during winding. Dehumidified air can be used to inflate the film as it exits the die in the case of the blow tube method. Talc can also be included in the air stream to prevent film blocking.

When the mixture is extruded into a strand shape, the strand can be formed into a pellet shape by extruding from a multi-hole strand nozzle and cutting with a rotary cutter. In order to prevent the pellets from sticking, vibration can be applied regularly or constantly, and the moisture in the pellets can be removed by hot air, dehumidified air or an infrared heater.

(Manufacturing by recycling)
The resin composition of the present invention is excellent in recyclability. In the present specification, recyclability refers to a material (X1) containing a component (A) and a component (B) constituting the resin composition, and optionally a component (C) and / or a component (D). It shows the property that it can be reused to form the resin composition of the present invention. In particular, it is preferable to reuse the layer made of the material (X1) and the laminate containing the layer to form the resin composition of the present invention. Here, the material (X1) is meant to include not only the case where the composition of the resin composition of the present invention is satisfied but also the case where the composition is not satisfied.

Since the resin composition of the present invention is excellent in recyclability, even if it is formed by reusing the material (X1), it is excellent in stretchability, impact strength under low temperature and low humidity, and adhesive strength in the obtained laminate. In addition, the resin composition of the present invention can be repeatedly recycled.

When the material (X1) is reused to form the resin composition of the present invention, the step (1) in the method for producing the resin composition is the material (X1) and the polyol plasticizer (C) and / or the thermoplastic. It is preferable to include a step (also referred to as step (Z)) of mixing the material (X2) containing the resin (D). In the step (Z), the material (X1) is mixed with the material (X2) containing the polyol plasticizer (C) and / or the thermoplastic resin (D), preferably at least the polyol plasticizer (C). Therefore, it is easy to form the resin composition of the present invention without impairing the effects of the present invention (stretchability, impact strength, adhesive strength, etc.).

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

When the material (X1) is a single-layer sheet or a multi-layer sheet, it is preferable to crush the sheet with a crusher in advance before mixing with an extruder. The form of the material (X2) may be in the form of a sheet, but from the viewpoint of production efficiency, it is preferably in the form of a pellet, for example, a form that does not need to be subjected to a crusher.

Here, when the thermoplastic resin (D) is a water-insoluble thermoplastic resin, conventionally, since the water-soluble polymer and the water-insoluble thermoplastic resin have poor compatibility, for example, modified starch or water-soluble. It is difficult to recycle a material containing at least a thermoplastic polymer and a thermoplastic resin, particularly a material in the form of a laminate (for example, a laminate in which the inner layer contains modified starch and a water-soluble polymer and the outer layer contains a thermoplastic resin). rice field. However, the present inventor has surprisingly found that even such a material can be recycled by adjusting the composition of the resin composition of the present invention to improve compatibility. I found it.

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

Further, 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 effect of the present invention, so that the material (X1) is preferably a laminate. The laminate may be the laminate of the present invention or a laminate other than the present invention, but from the viewpoint that the laminate of the present invention can be reused, the laminate of the present invention is preferable. Is.

When the material (X1) is a laminate, the step (Z) is preferably a step of melt-kneading the material (X1) which is a laminate and the material (X2), and more preferably a pre-crushed laminate. As described above, this is a step of melt-kneading the body material (X1) and the material (X2) using an extruder.

An example of the mode of the combination of the material (X1) and the material (X2) is shown below. In the following aspects, both the material (X1) and the 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).

When the material (X1) is a laminated body, the laminated body is not particularly limited, but in addition to the laminated body of the present invention described in the section of [laminated body], for example, in the order of L2 layer / L3 layer / L2 layer. A laminate having each layer can be mentioned.

[Manufacturing method of laminated body]
The method for producing the laminate of the present invention is not particularly limited, and is, for example, a method of coextrusion molding; a method of coating a composition extruded from an extruder on a layer conveyed by a taker; a method of combining these. It's okay.

In one embodiment of the present invention, the method for producing a laminate of the present invention can preferably use a step of coextruding an L1 layer and another layer including an L2 layer and / or an L3 layer. The other layer may include the layer (W).

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

Further, in one embodiment of the present invention, the method for producing a laminate of the present invention preferably comprises a step of coextruding and a step of coating the coextruded composition on a layer conveyed by a take-up machine. include. 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, the resin composition forming the L1 layer and the composition forming the L2 layer are extruded. They are charged into the machine, whereby these compositions are plasticized and discharged from the multi-layer film die outlet. Then, the composition co-extruded from the die outlet is coated on the L3 layer conveyed by the take-up machine, preferably the roller-type take-up machine, so that the L1 layer and the L2 layer are laminated on the L3 layer. Further, by coating the opposite surface of the L3 layer in the same manner, a laminate having the L2 layer / L1 layer / L3 layer / L1 layer / L2 layer in this order can be obtained. The obtained laminate is conveyed while being crimped with a pressure roll or the like, and can be wound into a roll by a winder. The laminate according to another embodiment of the present invention can be produced by appropriately modifying the laminate according to the layer structure and composition of the laminate based on a conventional method or the above embodiment.

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

[recycling]
One embodiment of recycling in the present invention will be described in more detail.
FIG. 1 is a schematic view showing a scheme for recycling a laminate according to an embodiment of the present invention. The laminate 1 is a laminate other than the present invention, and is a laminate having an L3 layer / L2 layer / L3 layer in this order. When the laminate 1 is recycled, the resin is formed by mixing the material (X1) which is the laminate 1 and the material (X2) containing the polyol plasticizer (C) and / or the thermoplastic resin (D). The composition 2 is formed. Next, the obtained resin composition 2 is coextruded or the like to form a laminate 3 including an L1 layer made of the resin composition 2. As a result, the L1 layer in the laminated body 3 becomes a recycled layer (also referred to as a recovery layer). The layer structure of the laminated body 3 is in the order of L2 layer / L1 layer (recovery layer) / L3 layer / L1 layer (recovery layer) / L2 layer. Next, the resin composition 4 is formed by mixing the material (X1) which is the laminate 3 and the material (X2') containing the polyol plasticizer (C) and / or the thermoplastic resin (D). In the same manner as described above, the obtained resin composition 4 is coextruded 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 laminated body 5 is in the order of L2 layer / L1'layer (recovery layer) / L3 layer / L1'layer (recovery layer) / L2 layer. As described above, the resin composition or laminate of the present invention can be repeatedly recycled, and even if the recycled resin composition or laminate has excellent stretchability, impact strength, adhesive strength, etc. Can have.

Further, for example, when the sheet-shaped laminated body 1 is molded into a coffee capsule container and used, many thermoformed burrs (for example, about 50%) remain, but in the present invention, such thermoformed burrs (laminated body) are left. Since 1) can be repeatedly recycled as shown in FIG. 1, for example, the environmental load can be reduced. In particular, in food containers or packaging materials, many skeletons are often generated during production, such as the thermoformed burrs of the coffee capsule container, so that the resin composition and laminate of the present invention can be preferably used.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

<Test method>

(1) Breaking point strain The stretchability of the resin compositions (single-layer sheets) obtained in Examples and Comparative Examples was evaluated according to the following method.
The 250 μm single-layer sheets obtained in Examples and Comparative Examples were cut into strips having a width of 15 mm and a length of 10 cm. Next, both ends of the short side of the cut sample were sandwiched between the chucks of the following tensile testers, and then a constant speed (500 mm / min) was applied to stretch and measure until the sample was broken. When the distance between the chucks before stretching is set to the initial length A ₀ (mm) and the distance between the chucks at the time of breaking is set to the breaking length A ₁ (mm), the breaking point of the single-layer sheet is set by the following formula. The strain was calculated.
Break point strain (%) = A ₁ / A ₀ x 100
Tensile tester: Instron "INSTRON3637", load cell 500N
The stretchability of the resin composition (single layer sheet) can be evaluated to be good if the breaking point strain is 170% or more.

(2) Impact Strength The impact strength of the resin compositions (single layer sheets) obtained in Examples and Comparative Examples at low temperature and low humidity was evaluated according to the following method.
The 250 μm single-layer sheets obtained in Examples and Comparative Examples were cut into squares having a width of 10 cm and a length of 10 cm. Next, after adjusting the humidity of the cut sample for 2 weeks under the conditions of a temperature of 0 ° C. and a humidity of 10% RH, the sample is fixed on the sample table of the following impact strength tester, and a pendulum with a 15 kg weight destroys the sample. The energy required for this was measured, and the impact strength was calculated by the following formula.
Impact strength (mN / μm) = Energy required to destroy the sample (kgf · cm) × 1000 × 0.098 / Sample thickness (μm)
Impact strength tester: "Film Impact Tester" manufactured by Toyo Seiki Co., Ltd.
If the impact strength of the resin composition (single layer sheet) is 2.5 mN / μm or more, it can be evaluated to be good.

(3) Adhesive strength The adhesive strength of the laminates (multilayer sheets) obtained in 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 Examples and Comparative Examples were cut into strips having a width of 15 mm and a length of 10 cm. 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 (of the two interfaces). One) was used as the interface to be measured.
The cut sample is humidity-controlled for 2 weeks under the conditions of a temperature of 23 ° C. and a humidity of 50% RH, and then peeled off by pulling the interface to be measured under the following conditions using the following device, and the adhesive strength at each interface is obtained. Was measured.
Measuring device: Instron "INSTRON3637", load cell maximum load 1kN
Measurement conditions: Temperature: 23 ° C, Humidity: 50% RH, Peeling surface angle: 180 °
Adhesive strength (N / 15m) = Energy required to peel off the sample (kgf) x 9.8
If the adhesive strength at the interface between the L2 layer and the L1 layer is 25 N / 15 mm or more, it can be evaluated as good, and if the adhesive strength at the interface between the L3 layer and the L1 layer is 15 N / 15 mm or more, it is good. Can be evaluated as.

(4) Thickness The thickness of each layer of the single-layer sheet and the multi-layer sheet obtained in Examples and Comparative Examples was cross-sectionald and measured with an optical microscope.
Cross-sectioning device: "Small rotary microtome PR-50" manufactured by Daiwa Kouki Kogyo Co., Ltd.
Measuring device: "ECLIPSE Ci-E" manufactured by Nikon Corporation

(5) Method for measuring viscosity of polyvinyl alcohol According to JIS Z 8803 (falling ball viscometer) and JIS K 6726 (polyvinyl alcohol test method), a 4% aqueous solution of polyvinyl alcohol in Examples and Comparative Examples was prepared, and a hebrewer was used. The viscosity at 20 ° C. was measured using a viscometer and used as the viscosity (20 ° C.) in a 4% aqueous solution of polyvinyl alcohol.

(6) Materials used <Modified starch (A)>
(A-1): ECOFILM ™; corn starch modified with propylene oxide, amylose content 70% by mass, manufactured by Ingredition. (A-2): National 1658 ™; corn modified with propylene oxide. Starch, amylose content 20% by mass, manufactured by Ingredition

<Water-soluble polymer (B)>
(B-1): ELVANOL ™ 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.

<Polyplasticizer (C)>
・ (C-1): Sorbitol SG; Sorbitol, manufactured by Bussan Food Science Co., Ltd. ・ (C-2): Xylitol manufactured by Fuji Film Wako Pure Chemical Industries, Ltd. ・ (C-3): Sucrose manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.

<Thermoplastic resin (D)>
(D-1): Ecobio ™ F2341; 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) 6g / 10min (210 ° C, 2.16kg), manufactured by Nature Works (D-3): SKYGREEN K2012 ™; PETG, manufactured by SK Chemicals (D-4): Novatec LD ™ LC600A; low density polyethylene, MFR (Melt Flow Rate) 7 g / 10 min (190 ° C, 2.16 kg), manufactured by Nippon Polyethylene Co., Ltd. (D-5): Novatec PP EA7AD (trademark) EA7AD; polypropylene, MFR (Melt Flow Rate) 1.4 g / 10 min (230 ° C, 2.16 kg), manufactured by Nippon Polypro Co., Ltd. Thermoplastic resins (D-1) and (D-2) are EN13432. It has biodegradability in a biodegradability test based on.

<Example 1>
(Making a single layer sheet)
A single-layer film containing 67% by mass of modified starch (A-1), 23% by mass of modified starch (A-2), and 10% by mass of a water-soluble polymer (B-1) as raw materials is crushed (" It was used in an ultracentrifugation crusher (manufactured by ZM100 Resch). Hereinafter, the modified starch (A) containing 67% by mass of the modified starch (A-1) and 23% by mass of the modified starch (A-2) will be referred to as a modified starch (A'). The average amylose content of the modified starch (A') was 58% by mass.

Polypolyplasticizer (containing in a proportion of 90% by mass of modified starch (A') and 10% by mass of water-soluble polymer (B-1)) of a film piece crushed by a crusher. 16.7 parts by mass of C-1) and 67.9 parts by mass of the thermoplastic resin (D-1) were added, and the mixture was mixed and kneaded by a twin-screw extruder. The screw diameter, L / D ratio, rotation speed, operation method, and temperature profile (Table 1) of the twin-screw extruder are as shown below, and a schematic view of the twin-screw extruder is shown in FIG. .. Further, in Example 1, the material (X1) is a single-layer film, and the material (X2) is 16.7 parts by mass of a polyol plasticizer (C-1) and 67.9 parts by mass of a thermoplastic resin (D-). 1).

スクリュー直径：２７ｍｍ
Ｌ／Ｄ比：４８
スクリュー回転速度１００ｒｐｍ
運転方式：共回転（かみ合せ自己ワイピング）方式

Screw diameter: 27 mm
L / D ratio: 48
Screw rotation speed 100 rpm
Operation method: Co-rotation (engagement self-wiping) method

When the mixture was supplied to the twin-screw extruder, it was supplied into the barrel through the hopper in C1 at a speed of 4 kg / hour via the weight feeder of the twin-screw extruder. The temperature range of C5 to C9 was a cooking range, and complete gelatinization was completed within these bands to prepare the resin composition. The film-forming die is after C11.

A single-layer sheet (L1) made of the resin composition was produced by extruding the resin composition from the film-forming die of the twin-screw extruder, forming a film with a cast roll, and taking it back. The single-layer sheet (L1) has a thickness of 250 μm, modified starch (A') 13.8% by mass, water-soluble polymer (B-1) 1.5% by mass, and polyol plasticizer (C-1) 16. It had a composition of 0.7% by mass and 67.9% by mass of the thermoplastic resin (D-1).

(Making a multi-layer sheet)
Separately, in the above-mentioned twin-screw extruder, with the following strand dies attached to C11 or later of the twin-screw extruder, each component is mixed and kneaded by the same method as above, and the obtained resin composition is obtained. Extruded from a multi-hole strand nozzle in a twin-screw extruder. Pellets were prepared by cutting the strands obtained with a rotary cutter. The composition of the pellet was similar to that of the single layer sheet (L1).
Strand die: 450mm width Coat hanger die Lip opening 0.2mm
Distance between die-cast roll (air gap): 10 mm

As the L1 layer, the obtained pellets (modified starch (A') 13.8% by mass, water-soluble polymer (B-1) 1.5% by mass, polyol plasticizer (C-1) 16.7% by mass, And the thermoplastic resin (D-1) containing 67.9% by mass) was put into the single-screw extruder (1) shown in Table 2 and extruded from the multi-layer film-forming die. Further, as the L2 layer, the thermoplastic resin (D-1) crushed into pellets was put into the single-screw extruder (2) shown in Table 3 and extruded from the multi-layer film forming die.
Next, the above-mentioned multi-layer film formation was performed on both surfaces of the sheet (including L3 layer, 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. The resin composition to be the L1 layer extruded from the die was coated, and further, the resin to be the L2 layer extruded from the multi-layer film forming die was coated on both sides thereof. Immediately after being pressure-bonded to the sheet (L3 layer) with a pressure roll, it was wound into a roll with a winder to obtain a laminated body (multilayer sheet). The multilayer sheet had a layer structure having an 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.

吐出量：２.５ｋｇ／ｈｒ
ダイ−キャストロール間の距離（エアーギャップ）：１５０ｍｍ Single-screw extruder (1): Extruder manufactured by Plastic Engineering Laboratory (screw diameter 32 mm, L / D ratio = 28)
Preset temperature:

Discharge rate: 2.5 kg / hr
Distance between die-cast roll (air gap): 150 mm

吐出量：０.５ｋｇ／ｈｒ
ダイ−キャストロール間の距離（エアーギャップ）：１５０ｍｍ Single-screw extruder (2): Toyo Seiki extruder (screw diameter 20 mm, L / D ratio = 20)
Preset temperature:

Discharge rate: 0.5 kg / hr
Distance between die-cast roll (air gap): 150 mm

<Examples 2 to 8, 11 and 12, and Comparative Examples 1 to 11>
The contents of the modified starch (A) and the water-soluble polymer (B), and the types and addition amounts of the polyol plasticizer (B) and the thermoplastic resin (D) were adjusted as shown in Table 5. A single-layer sheet (resin composition) and a multi-layer sheet (laminated body) were obtained by the same method as in Example 1 except for the above. In Examples 8 and 12, in consideration of the type of the thermoplastic resin (D), the locations (C5 to C11, the adapter and the die) at 200 ° C. in the twin-screw extruder shown in Table 1 are 220 ° C., respectively. , 230 ° C., and 220 ° C. (C2-C4, adapter and die) at 180 ° C. in the single-screw extruder (1) shown in Table 2 and the single-screw extruder (2) shown in Table 3. The temperature was changed to 230 ° C. Further, in Table 5, all starches (A) are modified starches (A'), and all water-soluble polymers (B) are water-soluble polymers (B-1).

<Example 9>
(Manufacturing of multi-layer structure)
As the L2 layer, the thermoplastic resin (D-1) crushed into pellets was put into the single-screw extruder (3) shown in Table 4 and extruded from the multi-layer film forming die. The multi-layer film-forming die on both sides of a sheet (L3 layer, 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. The resin (L2 layer) extruded from the above was coated, and immediately pressed against the sheet (L3 layer) with a pressure roll, and then wound into a roll with a winder to obtain a multilayer structure. The multilayer structure had a layer structure having an L2 layer [50 μm] / L3 layer [450 μm] / L2 layer [50 μm] in this order. The numbers in parentheses indicate the thickness of each layer.

吐出量：０.５ｋｇ／ｈｒ
ダイ−キャストロール間の距離（エアーギャップ）：１５０ｍｍ Single-screw extruder (3): Extruder manufactured by Plastic Engineering Laboratory (32 mm diameter, L / D = 28)
Preset temperature:

Discharge rate: 0.5 kg / hr
Distance between die-cast roll (air gap): 150 mm

(Recycling of multi-layer structure)
The multilayer structure obtained above was crushed by a crusher (“ultracentrifugal crusher”, manufactured by ZM100 Resch). Film pieces crushed by a crusher [contains 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)] To 18.8 parts by mass, 16.7 parts by mass of polyol plasticizer (C-1) and 64.5 parts by mass of thermoplastic resin (D-1) were added, and mixed and kneaded by a twin-screw extruder. (Implemented in Example 1 under the conditions shown in Table 1 above) to obtain a resin composition having the same composition as in Example 1. Using the obtained resin composition, a single-layer sheet (resin composition) and a multilayer sheet (laminated body) were obtained in the same manner as in Example 1. In Example 9, the material (X1) is a multilayer structure, and the material (X2) is 16.7 parts by mass of a polyol plasticizer (C-1) and 64.5 parts by mass of a thermoplastic resin (D-). 1).

<Example 10>
(Recycling of laminated body)
The multilayer sheet (laminated body) obtained in Example 1 was pulverized by a crusher (“ultracentrifugal crusher”, manufactured by ZM100 Resch). Film pieces crushed by a crusher [starch (A') 36.6% by mass, water-soluble polymer (B-1) 4.0% by mass, polyol plasticizer (C-1) 9.5% by mass and heat Contains 49.8% by mass of the plasticizer (D-1)] 13.1 parts by mass of the polyol plasticizer (C-1) and 49.1 parts of the thermoplastic resin (D-1) with respect to 37.7 parts by mass. A part by mass was added, and the mixture was mixed and kneaded with a twin-screw extruder (implemented under the conditions shown in Table 1 in Example 1) to obtain a resin composition having the same composition as that of Example 1. Using the obtained resin composition, a single-layer sheet (resin composition) and a multilayer sheet (laminated body) were obtained in the same manner as in Example 1. In Example 10, the material (X1) is the multilayer sheet (laminated body) obtained in Example 1, and the material (X2) is 13.1 parts by mass of the polyol plasticizer (C-1) and 49. 1 part by mass of thermoplastic resin (D-1).

<Example 13>
Under the following conditions, the multilayer sheet obtained in Example 1 was molded into a coffee capsule container.
Equipment: Compressed air vacuum forming machine (FKS-0632-20)
Thermoforming temperature: 115 ° C
Draw ratio: 0.5
Pressure: 0.5 MPa
Compression time: 4 seconds

The breaking point strain, impact strength and adhesive strength were measured using the single-layer sheet and the multi-layer sheet obtained in Examples 1 to 12 and Comparative Examples 1 to 11. The results and the pass range are shown in Table 5. In addition, the amount of starch (A) and water-soluble polymer (B) added, the type and amount of polyol plasticizer (C) and thermoplastic resin (D) added, and the mass / polyol plasticizer of modified starch (A). The mass (A / C) of (C) is also shown in Table 5.

As shown in Table 5, it was confirmed that the single-layer sheets obtained in Examples 1 to 12 had good evaluations of both stretchability and impact strength under low temperature and low humidity. On the other hand, it was confirmed that the single-layer sheets obtained in Comparative Examples 1 to 11 were poor in both stretchability and / or impact strength. It was also confirmed that the multilayer sheets obtained in Examples 1 to 12 had good adhesive strength at the interface. Therefore, it was found that the resin composition of the present invention can achieve both excellent stretchability and excellent impact strength under low temperature and low humidity, and that the laminate containing the layer made of the resin composition has excellent adhesive strength at the interface. rice field.
Further, in Example 9, a multilayer structure was used, and in Example 10, a laminate of the present invention was used to prepare a resin composition having the same composition as that of Example 1, and a single-layer sheet using the same composition was prepared. Obtained. The single-layer sheets obtained in Examples 9 and 10 showed good evaluation results almost the same as those in Example 1. From this result, it was also found that the resin composition and the laminate of the present invention are excellent in recyclability.

1,3,5 ... Laminated body (layer structure), 2,4 ... Resin composition, 8 ... Biaxial extruder, 9 ... Hopper, 10 ... Liquid addition nozzle, 11 ... Resin thermometer, 12 ... Resin pressure gauge, 13 ... adapter, 14 ... die

Claims (18)

6-45 parts by mass of modified starch (A),
1 to 5 parts by mass of water-soluble polymer (B),
It contains 1 to 50 parts by mass of the polyol plasticizer (C) and 5 to 80 parts by mass of the thermoplastic resin (D) different from the water-soluble polymer (B), and contains the following formula (1);
0 <mass of (A) / mass of (C) <1 (1)
The resin composition, wherein the total content of (A), (B), (C) and (D) is 100 parts by mass. The total content of the modified starch (A), the water-soluble polymer (B), the polyol plasticizer (C) and the thermoplastic resin (D) is 80% by mass or more based on the mass of the resin composition. Item 2. The resin composition according to Item 1. 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. The resin composition according to any one of claims 1 to 3, wherein the water-soluble polymer (B) is a polyvinyl alcohol-based resin. The polyol plasticizer (C) is 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. The resin composition according to any one of claims 1 to 4, which comprises. The resin composition according to any one of claims 1 to 5, wherein the thermoplastic resin (D) contains at least one selected from a polyolefin-based resin and a polyester-based resin. The resin composition according to any one of claims 1 to 6, wherein the thermoplastic resin (D) contains a biodegradable thermoplastic resin having biodegradability in a biodegradability test based on EN13432. A film or sheet comprising the resin composition according to any one of claims 1 to 7. The L1 layer made of the resin composition according to any one of claims 1 to 7 and
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 consisting of. A layer structure having an L3 layer / L1 layer / L3 layer in this order,
A claim that includes at least a part of a layer structure selected from a group consisting of 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. 9. The laminate according to 9. 9. Laminated body. The laminate according to any one of claims 9 to 11, wherein the total thickness of the L1 layer is 10 to 1000 μm, the total thickness of the L2 layer is 5 to 1000 μm, and the total thickness of the L3 layer is 20 to 2000 μm. A material (X1) containing 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),
The method for producing a resin composition according to any one of claims 1 to 7, which comprises a step of mixing. In the step, 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). The method according to claim 13. The method according to claim 13 or 14, wherein the step is a step of melt-kneading the material (X1) which is a laminated body and the material (X2). The method according to claim 15, wherein the laminate is the laminate according to any one of claims 9 to 12. The method for producing a laminate according to any one of claims 9 to 12, which comprises a step of coextruding the L1 layer and another layer including the L2 layer and / or the L3 layer. A container made of the laminate according to any one of claims 9 to 12.

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