Laminate

Abstract

The present invention provides a laminate having excellent biodegradability, and at least excellent high-speed formability and / or appearance.　The laminate has a base material layer and a seal layer on at least one surface of the base material layer. The seal layer is composed of a resin composition including an aliphatic polyester resin (A). The aliphatic polyester resin (A) includes, as main structural units, a repeating structural unit A1 derived from an aliphatic diol and a repeating structural unit A2 derived from an aliphatic dicarboxylic acid. The repeating structural unit A2 derived from an aliphatic dicarboxylic acid at least includes a repeating structural unit A21 derived from succinic acid and a repeating structural unit A22 derived from a C9-36 aliphatic dicarboxylic acid.

Description

Laminate

[0001] The present invention relates to a laminate.

[0002] In recent years, concerns about ecosystem and environmental pollution due to marine disposal of plastic products have become apparent. For example, in Europe, regulations and laws are being enacted that prohibit the use of disposable plastic shopping bags in retail stores and disposable plastic containers such as cups and plates. Various regulations are being enacted around the world from the perspective of preventing environmental pollution. Recently, there has been a demand for biodegradable plastic products (home compostable products) that can be composted in ordinary households, as well as plastic products that combine moldability and quality from the perspectives of cost and practical use.

[0003] Conventionally, known biodegradable plastics (resins) include polybutylene succinate (hereinafter abbreviated as PBS), polybutylene terephthalate / adipate (hereinafter abbreviated as PBAT), polybutylene succinate / terephthalate (hereinafter abbreviated as PBST), and polylactic acid (hereinafter abbreviated as PLA). Furthermore, known biodegradable resins that are particularly suitable for home composting include polybutylene succinate / adipate (hereinafter abbreviated as PBSA) and polyhydroxyalkanoate (hereinafter abbreviated as PHA). PHAs include poly(3-hydroxybutyrate) (hereinafter abbreviated as PHB), poly(3-hydroxybutyrate / 3-hydroxyvalerate) (hereinafter abbreviated as PHBV), poly(3-hydroxybutyrate / 3-hydroxyhexanoate) (hereinafter abbreviated as PHBH), and poly(3-hydroxybutyrate / 4-hydroxybutyrate).

[0004] Patent Document 1 discloses a release substrate formed by melt-extrusion coating a substrate with a specific aliphatic polyester resin to form a filler layer. It describes that the use of this specific aliphatic polyester resin ensures good adhesion and adhesion of the filler layer to the substrate even when laminated on the substrate at low temperatures. Furthermore, the low melt-coating temperature suppresses the generation of oxidative odor and smoke during molding, and further provides a substrate that is decomposable by common microorganisms found in nature. Patent Document 1 also describes that the aliphatic polyester in Patent Document 1 is primarily composed of a polyester synthesized from glycols and an aliphatic polybasic acid or its acid anhydride. It also describes that, to achieve a sufficiently high molecular weight, a relatively high molecular weight polyester prepolymer having hydroxy groups at both ends is synthesized, and then the prepolymer is further coupled with a coupling agent. Patent Document 1's examples also describe the use of PBS or PBSA as the polyester prepolymer to obtain the aliphatic polyester.

[0005] Japanese Patent Application Publication No. 6-171050

[0006] According to the studies of the present inventors, the release substrate produced using the specific aliphatic polyester described in Patent Document 1 still has problems with high-speed formability and appearance after high-speed forming. The present invention has been made in consideration of the above-mentioned problems of the conventional technology, and aims to provide a laminate that has excellent biodegradability and is excellent at least in high-speed formability and / or appearance.

[0007] The gist of the present invention lies in the following [1] to

[20] .

[0008] [1] A laminate having a base layer and a seal layer on at least one surface of the base layer, wherein the seal layer is made of a resin composition containing an aliphatic polyester resin (A), wherein the aliphatic polyester resin (A) contains, as main structural units, a repeating structural unit A1 derived from an aliphatic diol and a repeating structural unit A2 derived from an aliphatic dicarboxylic acid, and wherein the repeating structural unit A2 derived from the aliphatic dicarboxylic acid contains at least a repeating structural unit A21 derived from succinic acid and a repeating structural unit A22 derived from an aliphatic dicarboxylic acid having 9 to 36 carbon atoms. [2] The laminate according to [1], wherein the repeating structural unit A2 derived from the aliphatic polyester resin (A) contains, as main structural units, a repeating structural unit A21 derived from succinic acid in the repeating structural unit A2 derived from the aliphatic dicarboxylic acid in an amount of 50 mol% to 99 mol%. [3] The laminate according to [1] or [2], wherein the aliphatic polyester resin (A), in the repeating structural units A2 derived from the aliphatic dicarboxylic acid, has a content of the repeating structural units A22 derived from the aliphatic dicarboxylic acid having 9 to 36 carbon atoms of 1 mol% or more and 50 mol% or less. [4] The laminate according to any of [1] to [3], wherein the repeating structural units A22 derived from the aliphatic dicarboxylic acid having 9 to 36 carbon atoms include a repeating structural unit derived from an aliphatic dicarboxylic acid having 9 to 13 carbon atoms. [5] The laminate according to any of [1] to [4], wherein the content of the repeating structural units A1 derived from the aliphatic diol is 25 mol% or more and 75 mol% or less, based on the number of moles of all structural units in the aliphatic polyester resin (A). [6] The laminate according to any one of [1] to [5], wherein the content of the repeating structural unit A2 derived from the aliphatic dicarboxylic acid is 25 mol% or more and 75 mol% or less, based on the number of moles of all structural units of the aliphatic polyester resin (A). [7] The laminate according to any one of [1] to [6], wherein the resin composition further comprises an aliphatic polyester resin (B) other than the aliphatic polyester resin (A).[8] The laminate according to [7], wherein the aliphatic polyester resin (B) comprises, as main structural units, a repeating structural unit B1 derived from an aliphatic diol and a repeating structural unit B2 derived from an aliphatic dicarboxylic acid, and the repeating structural unit B2 derived from the aliphatic dicarboxylic acid comprises a repeating structural unit derived from succinic acid. [9] The laminate according to [7] or [8], wherein the content of the aliphatic polyester resin (A) is 30% by weight or more and less than 100% by weight based on the total weight of the aliphatic polyester resin (A) and the aliphatic polyester resin (B).

[10] The laminate according to any of [1] to [9], wherein the proportion of the total number of moles of repeating structural units derived from an aliphatic dicarboxylic acid having 9 to 36 carbon atoms contained in the resin composition relative to the total number of moles of repeating structural units derived from all aliphatic dicarboxylic acids contained in the resin composition is 1 mol % or more and 50 mol % or less.

[11] The laminate according to any one of [1] to

[10] , wherein the ratio of the total number of moles of repeating structural units derived from aliphatic dicarboxylic acids having 9 to 36 carbon atoms contained in the resin composition to the total number of moles of repeating structural units derived from all aliphatic dicarboxylic acids contained in the resin composition is 5 mol% or more and 30 mol% or less.

[12] The laminate according to any one of [1] to

[11] , wherein the aliphatic polyester resin (A) has a storage modulus E' of 180 MPa or less at 100°C, as measured by solid viscoelasticity measurement in accordance with JIS K7244-4:1999, at a frequency of 1 Hz, a temperature range of 20°C to 130°C, and a heating rate of 3°C / min.

[13] The laminate according to any one of [1] to

[12] , wherein the aliphatic polyester resin (A) has a storage modulus G' of 60 MPa or less at 80°C, as measured by melt viscoelasticity measurement in accordance with JIS K7244-10:2005, at a frequency of 1 Hz. [Claim 14] The laminate according to any one of [1] to

[13] , wherein the aliphatic polyester resin (A) has a storage modulus G' of 80 MPa or less at 60°C, as determined by melt viscoelasticity measurement at a frequency of 1 Hz according to JIS K7244-10:2005.

[15] The laminate according to any one of [1] to

[14] , wherein the aliphatic polyester resin (A) has a melt tension of 20 mN or less at a temperature of 190°C, an extrusion speed of 10 mm / min, and a take-up speed of 4 m / min.

[16] The laminate according to any one of [1] to

[15] , wherein the aliphatic polyester resin (A) has a melt viscosity ratio of 4.0 or more, as expressed by the following mathematical formula (1): Melt viscosity ratio = η1 / η2 (1) (In formula (1), η1 is the melt viscosity ratio at a temperature of 190°C and a shear rate of 60.8 (sec). －１ ) represents the melt viscosity of the aliphatic polyester resin (A) at a temperature of 190°C and a shear rate of 1216 (sec －１ ) represents the melt viscosity of the aliphatic polyester resin (A).

[17] The laminate according to any one of [1] to

[16] , wherein the resin composition has a storage modulus E' at 100°C, as measured by solid state elasticity measurement in accordance with JIS K7244-4:1999, at a frequency of 1 Hz, in a temperature range of 20°C to 130°C, and at a heating rate of 3°C / min, of 180 MPa or less.

[18] The laminate according to any one of [1] to

[17] , wherein the resin composition has a storage modulus G' at 80°C, as measured by melt viscoelasticity measurement in accordance with JIS K7244-10:2005, at a frequency of 1 Hz, of 60 MPa or less.

[19] The laminate according to any one of [1] to

[18] , wherein the resin composition has a storage modulus G' at 60°C, as measured by solution viscoelasticity measurement in accordance with JIS K7244-10:2005, at a frequency of 1 Hz, of 80 MPa or less.

[20] The laminate according to any one of [1] to

[19] , wherein the resin composition has a melt tension of 20 mN or less at a temperature of 190°C, an extrusion speed of 10 mm / min, and a take-up speed of 4 m / min.

[0009] According to the present invention, a laminate having excellent biodegradability, high-speed formability and / or excellent appearance can be obtained.

[0010] The present invention is not limited to the following description and can be implemented with any modifications within the scope of the present invention. In this specification, when a numerical value or physical property value is enclosed before and after the prefix "to", the lower and upper limits are included as endpoints. When a numerical range is described in stages, any combination of the upper and lower limits of each numerical range is also disclosed. In this specification, the expression "A or B" can be interpreted as "at least one selected from the group consisting of A and B." Furthermore, in this specification, a description such as "at least one selected from the group consisting of XX, YY, and ZZ" means any of XX, YY, ZZ, a combination of XX and YY, a combination of XX and ZZ, a combination of YY and ZZ, or a combination of XX, YY, and ZZ. Although multiple embodiments are described in this specification, various conditions in each embodiment can be applied to each other to the extent applicable.

[0011] The present inventors conducted extensive research to solve the above-mentioned problems and discovered that a laminate that can effectively achieve the above-mentioned objectives can be obtained by incorporating a specific aliphatic polyester resin into the sealing layer of the laminate. That is, a laminate (hereinafter also referred to simply as "laminate") according to one embodiment of the present invention has a base layer and a sealing layer on at least one surface of the base layer, the sealing layer being made of a resin composition containing an aliphatic polyester resin (A), the aliphatic polyester resin (A) having as its main structural units a repeating structural unit A1 derived from an aliphatic diol and a repeating structural unit A2 derived from an aliphatic dicarboxylic acid, the repeating structural unit A2 derived from the aliphatic dicarboxylic acid including at least a repeating structural unit A21 derived from succinic acid and a repeating structural unit A22 derived from an aliphatic dicarboxylic acid having 9 to 36 carbon atoms. Because the sealing layer contains the highly biodegradable aliphatic polyester resin (A), such a laminate exhibits excellent biodegradability. The aliphatic polyester resin (A) contains, as the repeating structural units A2 derived from aliphatic dicarboxylic acid, a repeating structural unit A21 derived from succinic acid and a repeating structural unit A22 derived from an aliphatic dicarboxylic acid having 9 to 36 carbon atoms. This prevents the viscosity and tension of the resin composition in a molten state from becoming too high, which is thought to result in a laminate with excellent high-speed moldability and appearance. Furthermore, the aliphatic polyester resin (A) contains, as the repeating structural units A2 derived from aliphatic dicarboxylic acid, a repeating structural unit A21 derived from succinic acid and a repeating structural unit A22 derived from an aliphatic dicarboxylic acid having 9 to 36 carbon atoms. This allows the aliphatic polyester resin (A) to have high levels of both permeability into the substrate and solidification. Therefore, during the production of a laminate, the aliphatic polyester resin (A) penetrates into the substrate and then quickly solidifies, which is thought to result in good adhesion between the substrate and the sealing layer. Furthermore, since the aliphatic polyester resin (A) contains a repeating structural unit A21 derived from succinic acid and a repeating structural unit A22 derived from an aliphatic dicarboxylic acid having 9 to 36 carbon atoms, the crystallinity of the aliphatic polyester resin (A) is appropriately reduced, and it is thought that the resin will have excellent heat sealability between the sealing layers and marine biodegradability.

[0012] In this specification, an aliphatic diol refers to a compound in which two hydroxyl groups are bonded to an aliphatic hydrocarbon group, and the aliphatic hydrocarbon group is usually a straight-chain aliphatic hydrocarbon group, but may have a branched structure, a cyclic structure, or a plurality of such structures. Also, an aliphatic dicarboxylic acid refers to a compound in which two carboxyl groups are bonded to an aliphatic hydrocarbon group, and the aliphatic hydrocarbon group is usually a straight-chain aliphatic hydrocarbon group, but may have a branched structure, a cyclic structure, or a plurality of such structures.

[0013] Furthermore, the aliphatic polyester resin (A) is a polymer having repeating structural units, and each repeating structural unit is also referred to as a compound unit corresponding to the compound from which the repeating structural unit is derived. For example, a repeating structural unit derived from an aliphatic diol is also referred to as an "aliphatic diol unit (or diol unit)," and a repeating structural unit derived from an aliphatic dicarboxylic acid is also referred to as an "aliphatic dicarboxylic acid unit (or dicarboxylic unit)." In the present invention, the repeating structural unit A1 derived from an aliphatic diol refers to a repeating structural unit corresponding to an aliphatic diol, i.e., a repeating structural unit formed by the reaction of two hydroxyl groups possessed by an aliphatic diol. Furthermore, the repeating structural unit A2 derived from an aliphatic dicarboxylic acid refers to a repeating structural unit corresponding to an aliphatic dicarboxylic acid, i.e., a repeating structural unit formed by the reaction of two carboxy groups possessed by an aliphatic dicarboxylic acid. The "repeating structural unit A21 derived from succinic acid" refers to a "structural unit corresponding to succinic acid," i.e., a structural unit formed by the reaction of two carboxy groups possessed by succinic acid. Furthermore, the term "repeating structural unit A22 derived from an aliphatic dicarboxylic acid having 9 to 36 carbon atoms" refers to a "structural unit corresponding to an aliphatic dicarboxylic acid having 9 to 36 carbon atoms," i.e., a structural unit formed by the reaction of two carboxy groups possessed by an aliphatic dicarboxylic acid having 9 to 36 carbon atoms. In this specification, "wt%" and "parts by weight" are synonymous with "mass%" and "parts by mass," respectively. The term "main structural unit" generally refers to a structural unit that accounts for 80 mass% or more of the aliphatic polyester resin (A). It may be 90 mass% or more, and may also be 100 mass% when no structural units other than the main structural unit are contained. More specifically, having aliphatic diol units A1 and aliphatic dicarboxylic acid units A2 as main structural units means that the sum of the masses of the aliphatic diol units A1 and the aliphatic dicarboxylic acid units A2 is 80 mass% or more of the aliphatic polyester resin (A).Furthermore, for example, the sum of the masses of the aliphatic diol units A1 and the aliphatic dicarboxylic acid units A2 means the sum of the product of the mass of 1 mole of the aliphatic diol units A1 and the total number of moles of the aliphatic diol units A1, and the product of the mass of 1 mole of the aliphatic dicarboxylic acid units A2 and the total number of moles of the aliphatic dicarboxylic acid units A2, when the smallest ester units in the aliphatic polyester resin (A) are counted as 1 mole of the aliphatic diol units A1 and 1 mole of the aliphatic dicarboxylic acid units A2.

[0014] <Aliphatic Polyester Resin (A)> Aliphatic polyester resin (A) (hereinafter sometimes referred to as "polyester resin (A)") comprises, as main structural units, a repeating structural unit A1 derived from an aliphatic diol and a repeating structural unit A2 derived from an aliphatic dicarboxylic acid, and the repeating structural unit A2 derived from the aliphatic dicarboxylic acid comprises at least a repeating structural unit A21 derived from succinic acid (hereinafter also referred to as a succinic acid unit) and a repeating structural unit A22 derived from an aliphatic dicarboxylic acid having 9 to 36 carbon atoms (hereinafter also referred to as an aliphatic dicarboxylic acid unit having 9 to 36 carbon atoms). Furthermore, from the viewpoint of heat resistance, the aliphatic dicarboxylic acid unit A22 having 9 to 36 carbon atoms is preferably an aliphatic dicarboxylic acid unit having 9 to 13 carbon atoms.

[0015] One embodiment of the aliphatic polyester-based resin (A) according to the present invention is, for example, an aliphatic polyester-based resin (A) containing an aliphatic diol unit A1 represented by the following formula (1), a succinic acid unit A21 represented by the following structural formula (2), and an aliphatic dicarboxylic acid unit A22 represented by the following structural formula (3).

[0016] The aliphatic polyester resin (A) according to this embodiment may contain two or more types of aliphatic diol units A1 represented by the following structural formula (1), and may also contain two or more types of aliphatic dicarboxylic acid units A22 represented by the following structural formula (3). Furthermore, the resin may contain a structural unit other than these structural units. -O-R １ -O- (1) -OC-CH ２ -CH ２ -CO- (2) -OC-R ２ -CO- (3)

[0017] In structural formula (1), R １ represents a divalent aliphatic hydrocarbon group which may have a substituent. ２ is usually a substituted or unsubstituted divalent aliphatic hydrocarbon group having 7 to 34 carbon atoms, and preferably a substituted or unsubstituted divalent aliphatic hydrocarbon group having 7 to 11 carbon atoms. The aliphatic diol unit A1, succinic acid unit A21, and aliphatic dicarboxylic acid unit A22 represented by the above structural formulas (1), (2), and (3) may be derived from a compound derived from petroleum or a compound derived from a plant raw material, but are preferably derived from a compound derived from a plant raw material.

[0018] R １ and R ２ When the substituent and / or atom is substituted, the type of the substituent and / or atom is not particularly limited as long as the effects of the present invention can be obtained, and examples thereof include a halogen atom, a cyano group, an amino group, an ester group, an alkylcarbonyl group, an acetyl group, a silyl group, a boryl group, a nitrile group, a thio group, a seleno group, etc. These substituents and / or atoms may be of only one type or of two or more types.

[0019] The aliphatic diol that provides the diol unit A1 represented by the structural formula (1) is not particularly limited, but from the viewpoint of moldability and mechanical strength, an aliphatic diol having from 2 to 10 carbon atoms is preferred, and an aliphatic diol having from 4 to 6 carbon atoms is particularly preferred. Examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,4-cyclohexanedimethanol, and among these, 1,4-butanediol is particularly preferred.

[0020] The aliphatic dicarboxylic acid that provides the dicarboxylic acid unit A22 represented by the structural formula (3) is not particularly limited as long as it has 9 to 36 carbon atoms, but from the viewpoint of heat resistance, an aliphatic dicarboxylic acid having 9 to 13 carbon atoms is preferred. Examples of aliphatic dicarboxylic acids having 9 to 36 carbon atoms include azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, and brassylic acid, and among these, azelaic acid and sebacic acid are particularly preferred.

[0021] The content of the aliphatic dicarboxylic acid unit A2 in the aliphatic polyester resin (A) is not particularly limited, and from the viewpoint of biodegradability, it is usually 25 mol% or more, preferably 30 mol% or more, more preferably 35 mol% or more, even more preferably 40 mol% or more, and particularly preferably 45 mol% or more, relative to 100 mol% of all structural units constituting the aliphatic polyester resin (A), and is usually 75 mol% or less, preferably 70 mol% or less, more preferably 65 mol% or less, even more preferably 60 mol% or less, and particularly preferably 55 mol% or less. That is, the content of the aliphatic dicarboxylic acid unit A2 in the aliphatic polyester resin (A) is preferably 25 mol% to 75 mol%, particularly preferably 30 mol% to 70 mol%, further preferably 35 mol% to 65 mol%, even more preferably 40 mol% to 60 mol%, and particularly preferably 45 mol% to 55 mol%. In this specification, the number of moles of the repeating structural units in the aliphatic polyester resin (A) is counted with the smallest ester unit of the aliphatic polyester resin (A) as 1 mole.

[0022] The content of the aliphatic diol unit A1 in the aliphatic polyester resin (A) is not particularly limited, and from the viewpoint of biodegradability, it is usually 25 mol% or more, preferably 30 mol% or more, more preferably 35 mol% or more, even more preferably 40 mol% or more, and particularly preferably 45 mol% or more, relative to 100 mol% of all structural units constituting the aliphatic polyester resin (A), and is usually 75 mol% or less, preferably 70 mol% or less, more preferably 65 mol% or less, even more preferably 60 mol% or less, and particularly preferably 55 mol% or less. That is, the content of the aliphatic diol unit A1 in the aliphatic polyester resin (A), based on the number of moles of all structural units constituting the aliphatic polyester resin (A) (100 mol%), is preferably 25 mol% or more and 75 mol% or less, particularly preferably 30 mol% or more and 70 mol% or less, even more preferably 35 mol% or more and 65 mol% or less, still more preferably 40 mol% or more and 60 mol% or less, and particularly preferably 45 mol% or more and 55 mol% or less.

[0023] (1) Content of each structural unit in aliphatic polyester resin (A) The content of succinic acid unit A21 in aliphatic polyester resin (A) is not particularly limited, but from the viewpoint of moldability, the content of succinic acid unit A21 in the aliphatic dicarboxylic acid unit A2 in aliphatic polyester resin (A) is preferably 50 mol% or more, more preferably 60 mol% or more, even more preferably 70 mol% or more, and also preferably 99 mol% or less, more preferably 95 mol% or less, and from the viewpoint of biodegradation rate and surface smoothness, more preferably 89 mol% or less. That is, the content of succinic acid unit A21 is preferably 50 mol% or more and 99 mol% or less, particularly preferably 60 mol% or more and 95 mol% or less, and more preferably 70 mol% or more and 89 mol% or less, based on the total mole number of aliphatic dicarboxylic acid unit A2 in aliphatic polyester resin (A). The content of the aliphatic dicarboxylic acid units A22 having 9 to 36 carbon atoms in the aliphatic polyester resin (A) is not particularly limited, but from the viewpoints of high-speed moldability, heat-sealability, and appearance, the content of the aliphatic dicarboxylic acid units A22 having 9 to 36 carbon atoms in the aliphatic dicarboxylic acid units A2 in the aliphatic polyester resin (A) is preferably 1 mol% or more, more preferably 5 mol% or more, even more preferably 11 mol% or more, and preferably 50 mol% or less, more preferably 40 mol% or less, and even more preferably 30 mol% or less. That is, the content of the aliphatic dicarboxylic acid units A22 having 9 to 36 carbon atoms is preferably 1 mol% or more and 50 mol% or less, particularly preferably 5 mol% or more and 40 mol% or less, and even more preferably 11 mol% or more and 30 mol% or less, based on the total number of moles of the aliphatic dicarboxylic acid units in the aliphatic polyester resin (A).

[0024] (2) Content of each dicarboxylic acid unit in all polyester resins contained in the resin composition From the viewpoints of high-speed moldability, heat sealability, and appearance, it is preferable that the content of succinic acid units and aliphatic dicarboxylic acid units having 9 to 36 carbon atoms in all polyester resins contained in the resin composition relative to the aliphatic dicarboxylic acid units in all polyester resins contained in the resin composition satisfies the following range: The ratio (content) of the total number of moles of succinic acid units contained in the resin composition relative to the total number of moles of aliphatic dicarboxylic acid units in all polyester resins contained in the resin composition is preferably 40 mol% or more, more preferably 50 mol% or more, and also preferably 99 mol% or less, more preferably 97 mol% or less, even more preferably 95 mol% or less, and particularly preferably 89 mol% or less. That is, the content of succinic acid units in all polyester resins contained in the resin composition is preferably 40 mol% or more and 99 mol% or less, particularly preferably 40 mol% or more and 97 mol% or less, more preferably 50 mol% or more and 95 mol% or less, and particularly preferably 50 mol% or more and 89 mol% or less, based on the total number of moles of aliphatic dicarboxylic acid units in all polyester resins contained in the resin composition. The ratio (content) of the total number of moles of aliphatic dicarboxylic acid units having 9 to 36 carbon atoms contained in the resin composition to the total number of moles of aliphatic dicarboxylic acid units in all polyester resins contained in the resin composition is preferably 1 mol% or more, more preferably 3 mol% or more, even more preferably 5 mol% or more, particularly preferably 11 mol% or more, and also preferably 60 mol% or less, more preferably 50 mol% or less, and even more preferably 30 mol% or less. That is, the content of aliphatic dicarboxylic acid units having 9 to 36 carbon atoms in all polyester resins contained in the resin composition is preferably 1 mol% or more and 60 mol% or less, particularly preferably 3 mol% or more and 50 mol% or less, even more preferably 5 mol% or more and 30 mol% or less, and particularly preferably 11 mol% or more and 30 mol% or less, based on the total number of moles of aliphatic dicarboxylic acid units in all polyester resins.

[0025] When the content of succinic acid units and aliphatic dicarboxylic acid units having 9 to 36 carbon atoms in all polyester resins contained in the resin composition satisfies the preferred ranges of (1) and / or (2) above, it becomes possible to obtain a resin composition that can give a laminate (film) with improved high-speed moldability, heat sealability, heat resistance, easy biodegradability, and surface appearance.

[0026] (Other Copolymerization Components) Furthermore, for the purpose of improving heat resistance and strength, controlling biodegradability, etc., the aliphatic polyester resin (A) may contain one or more aliphatic dicarboxylic acid units A23 other than the succinic acid units A21 and the aliphatic dicarboxylic acid units A22 having 9 to 36 carbon atoms (hereinafter, these may be referred to as "other aliphatic dicarboxylic acid units"). When the aliphatic polyester resin (A) contains the other aliphatic dicarboxylic acid units A23 in addition to the succinic acid units A21 and the aliphatic dicarboxylic acid units A22 having 9 to 36 carbon atoms, the total content of the other aliphatic dicarboxylic acid units A23 in the aliphatic polyester resin (A) is usually 50 mol% or less, preferably 30 mol% or less, and more preferably 20 mol% or less, based on 100 mol% of all dicarboxylic acid units in the aliphatic polyester resin (A). That is, the content of the other aliphatic dicarboxylic acid units A23 is preferably 0 mol % or more and 50 mol % or less, particularly preferably 0 mol % or more and 30 mol % or less, and even more preferably 0 mol % or more and 20 mol % or less, based on all dicarboxylic acid units in the aliphatic polyester resin (A).

[0027] Examples of the aliphatic dicarboxylic acid that provides the other aliphatic dicarboxylic acid unit A23 include oxalic acid, malonic acid, and adipic acid.

[0028] The aliphatic polyester resin (A) may have a repeating structural unit (aliphatic oxycarboxylic acid unit) A3 derived from an aliphatic oxycarboxylic acid different from the repeating structural unit A1 and the repeating structural unit A2. Specific examples of the aliphatic oxycarboxylic acid component that provides the aliphatic oxycarboxylic acid unit A3 include aliphatic oxycarboxylic acids such as lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 6-hydroxycaproic acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, and 2-hydroxyisocaproic acid, as well as derivatives of these aliphatic oxycarboxylic acids, such as lower alkyl esters or intramolecular esters. When optical isomers exist, they may be in the D-form, L-form, or racemic form. Among these, lactic acid or glycolic acid, or derivatives thereof, are particularly preferred. These aliphatic oxycarboxylic acids may be used alone or as a mixture of two or more. The aliphatic oxycarboxylic acid component used as a raw material may be in the form of a solid, liquid, or aqueous solution.

[0029] When the aliphatic polyester resin (A) contains these aliphatic oxycarboxylic acid units A3, the content thereof is, from the viewpoint of moldability, preferably 20 mol% or less, more preferably 10 mol% or less, even more preferably 5 mol% or less, and most preferably 0 mol% (not included, i.e., below the detection limit) when all the structural units constituting the polyester resin (A) are taken as 100 mol%. That is, the content of the aliphatic oxycarboxylic acid units A3 is, based on the number of moles of all the structural units of the aliphatic polyester resin (A) (100 mol%), preferably 0 mol% or more and 20 mol% or less, particularly preferably 0 mol% or more and 10 mol% or less, more preferably 0 mol% or more and 5 mol% or less, and most preferably 0 mol% (not included, i.e., below the detection limit).

[0030] Furthermore, the aliphatic polyester resin (A) may contain, as dicarboxylic acid units other than the aliphatic dicarboxylic acid units, aromatic dicarboxylic acid units such as terephthalic acid or isophthalic acid, as long as the effects of the present invention are not impaired.

[0031] The aliphatic polyester resin (A) may have an increased melt viscosity by copolymerizing a tri- or higher functional aliphatic polyhydric alcohol, a tri- or higher functional aliphatic polycarboxylic acid or an acid anhydride thereof, or a tri- or higher functional aliphatic polyoxycarboxylic acid component.

[0032] Specific examples of trifunctional aliphatic polyhydric alcohols include trimethylolpropane and glycerin, and specific examples of tetrafunctional aliphatic polyhydric alcohols include pentaerythritol. These may be used alone or in combination of two or more. Specific examples of trifunctional aliphatic polycarboxylic acids or acid anhydrides thereof include propanetricarboxylic acid or its acid anhydride, and specific examples of tetrafunctional polycarboxylic acids or its acid anhydrides include cyclopentanetetracarboxylic acid or its acid anhydride. These may be used alone or in combination of two or more.

[0033] Trifunctional aliphatic oxycarboxylic acid components are divided into (i) a type having two carboxyl groups and one hydroxyl group in the same molecule, and (ii) a type having one carboxyl group and two hydroxyl groups in the same molecule, and either type can be used, but from the viewpoints of moldability, mechanical strength, and appearance of molded products, (i) a type having two carboxyl groups and one hydroxyl group in the same molecule, such as malic acid, is preferred, more specifically, malic acid is preferably used.Furthermore, tetrafunctional aliphatic oxycarboxylic acid components are divided into (i) a type having three carboxyl groups and one hydroxyl group in the same molecule, (ii) a type having two carboxyl groups and two hydroxyl groups in the same molecule, and (iii) a type having three hydroxyl groups and one carboxyl group in the same molecule, and either type can be used, but those having multiple carboxyl groups are preferred, more specifically, citric acid, tartaric acid, etc. These may be used alone or in combination of two or more.

[0034] When the aliphatic polyester resin (A) contains such a structural unit derived from a trifunctional or higher functional component, the content thereof, relative to all structural units constituting the polyester resin (A) as 100 mol %, is such that the lower limit is usually 0 mol % or more, preferably 0.01 mol % or more, and the upper limit is usually 5 mol % or less, preferably 2.5 mol % or less.

[0035] [Physical Properties of Aliphatic Polyester Resin (A)] (Solid Viscoelasticity) In measuring the solid viscoelasticity of the aliphatic polyester resin (A), the storage modulus E' measured at a temperature of 100°C and a frequency of 1 Hz according to Japanese Industrial Standards (JIS) K7244-4:1999 is preferably 180 MPa or less. Having the storage modulus E' at or below this value allows for a laminate with excellent low-temperature heat-sealability to be obtained. For the same reasons, the storage modulus E' is more preferably 150 MPa or less. The lower limit of the storage modulus E' is not particularly limited, but is typically 0 MPa or more. That is, the storage modulus E' of the aliphatic polyester resin (A) at a temperature of 100°C and a frequency of 1 Hz is preferably 0 to 180 MPa, and particularly preferably 0 to 150 MPa. The storage modulus E' is measured using a rotational rheometer according to JIS K7244-4:1999. In the examples described below, a rotational rheometer (trade name: ARES-G2; manufactured by TA Instruments) in DMA mode was used. Then, while increasing the temperature in the temperature range of 20°C to 130°C at a heating rate of 3°C / min, tensile deformation was performed at a frequency of 1 Hz, a strain of 0.1%, and a measurement interval of 1.0 s / point, and the storage modulus E' at each temperature was recorded. The value of the storage modulus E' at a temperature of 100°C was then obtained. The solid viscoelasticity of the aliphatic polyester resin (A) can be adjusted by the content of each structural unit of the aliphatic polyester resin (A). For example, the solid viscoelasticity value can be increased by increasing the content of succinic acid units A21, and the solid viscoelasticity value can be decreased by decreasing the content of succinic acid units A21.

[0036] (Melt Viscoelasticity) In the melt viscoelasticity measurement of the aliphatic polyester resin (A), the storage modulus G' measured at a temperature of 80°C and a frequency of 1 Hz according to JIS K7244-10:2005 is preferably 60 MPa or less. When the storage modulus G' is equal to or less than the above value, the anchor effect between the base layer and the seal layer is strengthened, thereby improving adhesion. For the same reason, the storage modulus G' is more preferably 40 MPa or less. The lower limit of the storage modulus G' is not particularly limited, but is usually 0 MPa or more. That is, the storage modulus G' of the aliphatic polyester resin (A) at a temperature of 80°C and a frequency of 1 Hz is preferably 0 to 60 MPa, and particularly preferably 0 to 40 MPa.

[0037] For the same reason, in the melt viscoelasticity measurement of the aliphatic polyester resin (A), the storage modulus G' measured at a temperature of 60°C and a frequency of 1 Hz according to JIS K7244-10:2005 is preferably 80 MPa or less, more preferably 70 MPa or less. The lower limit of the storage modulus G' is not particularly limited, but is typically 0 MPa or more. That is, the storage modulus G' of the aliphatic polyester resin (A) at a temperature of 60°C and a frequency of 1 Hz is preferably 0 to 80 MPa, particularly preferably 0 to 70 MPa. The storage modulus G' at each of the above temperatures (80°C, 60°C) is measured using a rotational rheometer according to JIS K7244-10:2005. In the examples described below, an "ARES-G2" (trade name, manufactured by TA Instruments) was used as the rotational rheometer. The measurement method involves placing a test piece (0.2 g) of the aliphatic polyester resin (A) to be measured on the plate of the rotational rheometer heated to 190°C and melting it under a nitrogen atmosphere. The test piece is then compressed between 8 mm diameter parallel plates to a distance of 0.5 to 2 mm, and any resin that protrudes from the plates is removed. After reaching 190°C, dynamic viscoelasticity measurements are performed at a frequency of 1 Hz, a strain of 0.1%, and a measurement interval of 1.0 s / point while cooling at a rate of 1°C / min, to measure the storage modulus G' in the range of 190 to 30°C. In this way, the storage modulus G' at temperatures of 60°C and 80°C is obtained. The melt viscoelasticity of the aliphatic polyester resin (A) can be adjusted by the content of each structural unit of the aliphatic polyester resin (A). For example, the melt viscoelasticity can be increased by increasing the content of the succinic acid unit A21, and the melt viscoelasticity can be decreased by decreasing the content of the succinic acid unit A21.

[0038] (Melt Viscosity Ratio) The melt viscosity ratio of the aliphatic polyester resin (A) represented by the following formula (1) is preferably 4.0 or more. The upper limit of the melt viscosity ratio is not particularly limited, but it can be, for example, 5.0 or less. That is, the melt viscosity ratio is preferably 4.0 or more and 5.0 or less. Melt Viscosity Ratio=(η1 / η2) (1) In formula (1), η1 is the melt viscosity ratio at a temperature of 190°C and a shear rate of 60.8 (sec－１ η2 represents the melt viscosity of the aliphatic polyester resin (A) at a temperature of 190°C and a shear rate of 1216 (sec －１ The melt viscosity ratio of the aliphatic polyester resin (A) at a shear rate of 60.8 (sec) is shown. By having the melt viscosity ratio in the above range, it is possible to suppress the appearance defects of the molten film due to melt fracture, etc., and to obtain a laminate with an excellent surface appearance of the seal layer. －１ ) is the shear rate applied to the resin in the melt flow rate (MFR) measurement, and the shear rate is 1216 (sec －１ ) is the shear rate applied to the resin during extrusion molding. The melt viscosities η1 and η2 are measured using a capillary rheometer based on JIS K7199:1999 (Method A). A capillary die with a diameter (inner diameter) of 1 mm and a length of 10 mm is used. The apparent shear rate at a test temperature of 190°C is 60.8 (sec －１ ) and 1216 (sec －１ In the examples described below, a "Capillograph" (trade name, manufactured by Toyo Seiki Seisakusho) was used as the capillary rheometer.

[0039] (Melt Tension) In the melt tension measurement of the aliphatic polyester resin (A), the average melt tension at a temperature of 190°C, an extrusion speed of 10 mm / min, and a take-up speed of 4 m / min is preferably 20 mN or less, and particularly preferably 18 mN or less. The lower limit of the melt tension is not particularly limited, but, for example, 5 mN or more is preferred, and 7 N or more is particularly preferred. That is, the melt tension of the aliphatic polyester resin (A) is preferably 5 mN or more and 20 mN or less, and particularly preferably 7 mN or more and 18 mN or less. When the melt tension value of the aliphatic polyester resin (A) is within the above range, the drawdown property of the molten film is improved, enabling even higher speed molding of the laminate. The melt tension is determined by measuring the stress when the aliphatic polyester resin (A) is stretched at a constant speed. A capillary rheometer is used for the measurement. For example, in the examples described below, a "Capilograph" (trade name, manufactured by Toyo Seiki Seisakusho) was used as the capillary rheometer. Measurement conditions were a resin temperature of 190°C, a cylinder extrusion speed of 10 mm / min, a take-up speed of 4 m / min, a capillary diameter of 1 mm, and a capillary length of 10 mm. The melt tension of the aliphatic polyester resin (A) can be adjusted by the molecular weight of the aliphatic polyester resin (A). That is, the melt tension can be increased by increasing the molecular weight, and the melt tension can be decreased by decreasing the molecular weight.

[0040] (Melt flow rate (MFR)) The melt flow rate (MFR) of the aliphatic polyester resin (A) is a value measured at 190 ° C. and a load of 2.16 kg according to JIS K7210-1:2014, and is usually 0.1 g / 10 min or more and 100 g / 10 min or less, but from the viewpoint of moldability and mechanical strength, it is preferably 40 g / 10 min or less, more preferably 20 g / 10 min or less, preferably 1.0 g / 10 min or more, more preferably 2.0 g / 10 min or more. That is, the MFR measured at 190 ° C. and a load of 2.16 kg according to JIS K7210-1:2014 is preferably 0.1 g / 10 min or more and 100 g / 10 min or less, particularly preferably 1.0 g / 10 min or more and 40 g / 10 min or less, and even more preferably 2.0 g / 10 min or more and 20 g / 10 min or less. The MFR of the aliphatic polyester resin (A) can be adjusted by the molecular weight of the aliphatic polyester resin (A). That is, the MFR can be reduced by increasing the molecular weight, and the MFR can be increased by decreasing the molecular weight.

[0041] (Melting Point) The melting point of the aliphatic polyester resin (A) is preferably 80°C or higher, more preferably 100°C or higher, and preferably 180°C or lower, more preferably 160°C or lower, and particularly preferably lower than 140°C. That is, the melting point of the aliphatic polyester resin (A) is preferably 80°C or higher and 180°C or lower, particularly preferably 100°C or higher and 160°C or lower, and even more preferably 100°C or higher and lower than 140°C. When there are multiple melting points, it is preferable that at least one melting point is within the above range. The glass transition temperature and melting point of the aliphatic polyester resin (A) can be measured using a differential scanning calorimeter (e.g., manufactured by Seiko Corporation, product name: DSC220). Specifically, about 5 mg of the aliphatic polyester resin (A) is precisely weighed, heated and melted under a nitrogen gas flow at a flow rate of 40 mL / min, cooled at a rate of 10°C / min, and then the glass transition temperature and melting point can be measured while the temperature is increased at a rate of 10°C / min.

[0042] (Weight-average molecular weight (Mw)) The molecular weight of the aliphatic polyester resin (A) can be measured by gel permeation chromatography (GPC). The weight-average molecular weight (Mw) of the aliphatic polyester resin (A) using monodisperse polystyrene as the standard is usually 10,000 or more and 1,000,000 or less. However, because this is advantageous in terms of moldability and mechanical strength, it is preferably 20,000 or more and 500,000 or less, more preferably 50,000 or more and 400,000 or less, and even more preferably 100,000 or more and 300,000 or less.

[0043] [Method for producing aliphatic polyester resin (A)] The method for producing the aliphatic polyester resin (A) according to this embodiment can employ a known method for producing polyesters. In addition, the polycondensation reaction at this time can be performed under suitable conditions that have been conventionally used, and is not particularly limited. Usually, a method is employed in which the degree of polymerization is further increased by carrying out a decompression operation after the esterification reaction has progressed.

[0044] When a diol component forming diol units (also referred to as "diol component providing diol units") and a dicarboxylic acid component forming dicarboxylic acid units (also referred to as "dicarboxylic acid providing dicarboxylic acid units") are reacted during the production of the aliphatic polyester resin (A), the amounts of the diol component and the dicarboxylic acid component used are set so that the aliphatic polyester resin (A) produced has the desired composition. Usually, the diol component and the dicarboxylic acid component react in substantially equimolar amounts, but the diol component is usually used in a 1 to 30 mol % excess over the dicarboxylic acid component because it is distilled off during the esterification reaction.

[0045] When the aliphatic polyester resin (A) contains components (optional components) other than the essential components such as polyfunctional component units, the corresponding compounds (monomers or oligomers) are reacted so that the polyfunctional component units also have the desired composition. In this case, there are no limitations on the timing and method of introducing the optional components into the reaction system, and they are arbitrary as long as the aliphatic polyester resin (A) suitable for the present invention can be produced.

[0046] The aliphatic polyester resin (A) is usually produced in the presence of a catalyst. As the catalyst, any catalyst that can be used in the production of known polyester resins can be selected as long as it does not significantly impair the effects of the present invention. Examples of the catalyst include metal compounds such as germanium, titanium, zirconium, hafnium, antimony, tin, magnesium, calcium, and zinc. Among them, titanium compounds and germanium compounds are preferred.

[0047] Examples of titanium compounds that can be used as catalysts include organic titanium compounds such as tetraalkoxytitanium compounds such as tetrapropyl titanate, tetrabutyl titanate, and tetraphenyl titanate. Among these, tetrapropyl titanate and tetrabutyl titanate are preferred in terms of price and availability.

[0048] In addition, other catalysts may be used in combination as long as the object of the present invention is not impaired. The catalysts may be used alone or in any combination and ratio of two or more.

[0049] The amount of catalyst used is arbitrary as long as it does not significantly impair the effects of the present invention, but is usually 0.0005% by mass or more, more preferably 0.001% by mass or more, and usually 3% by mass or less, preferably 1.5% by mass or less, relative to the amount of monomer used. That is, the amount of catalyst used is preferably 0.0005% by mass or more and 3% by mass or less, and particularly preferably 0.001% by mass or more and 1.5% by mass or less. By setting the amount of catalyst used within the above range, the effects of using the catalyst can be reliably enjoyed, production costs can be reduced, and discoloration of the obtained polymer and a decrease in hydrolysis resistance can be prevented.

[0050] The timing of introducing the catalyst is not particularly limited as long as it is before the polycondensation reaction, and it may be introduced when the raw materials are charged or when the pressure reduction is started.

[0051] The reaction conditions, such as temperature, polymerization time, and pressure, used in producing the aliphatic polyester resin (A) may be any as long as they do not significantly impair the effects of the present invention. However, the reaction temperature for the esterification reaction and / or transesterification reaction between the dicarboxylic acid component and the diol component typically has a lower limit of 150°C or higher, preferably 180°C or higher, and an upper limit of 260°C or lower, preferably 250°C or lower. That is, the reaction temperature is preferably 150°C or higher and 260°C or lower, and particularly preferably 180°C or higher and 250°C or lower. By maintaining the reaction temperature within the above range, excessive generation of unsaturated bonds can be more reliably suppressed, gelation due to unsaturated bonds can be prevented, and the polymerization reaction can be more effectively controlled. The reaction atmosphere is typically an inert atmosphere such as nitrogen or argon. Furthermore, the reaction pressure is typically atmospheric pressure to 10 kPa, with atmospheric pressure being preferred. The reaction time typically has a lower limit of 1 hour or higher and an upper limit of 10 hours or lower, preferably 6 hours or lower, and more preferably 4 hours or lower. That is, the reaction time is preferably from 1 hour to 10 hours, particularly preferably from 1 hour to 6 hours, and more preferably from 1 hour to 4 hours.

[0052] The polycondensation reaction after the esterification reaction and / or transesterification reaction between the dicarboxylic acid component and the diol component is carried out under a pressure of usually 0.01×10 ３ Pa or more, preferably 0.03 × 10 ３ Pa or more, and the upper limit is usually 1.4 × 10 ３ Pa or less, preferably 0.4 × 10 ３ It is desirable to carry out the polycondensation reaction under a vacuum of 0.01×10 Pa or less. ３ Pa or more 1.4×10 ３ Pa or less is preferable, and 0.03 × 10 ３ Pa or more 0.4×10 ３Pa or less is particularly preferred. Furthermore, the reaction temperature in the reaction has a lower limit of usually 150°C or more, preferably 180°C or more, and an upper limit of usually 260°C or less, preferably 250°C or less. That is, the reaction temperature in the reaction is preferably 150°C or more and 260°C or less, and particularly preferably 180°C or more and 250°C or less. By keeping the reaction temperature within the above range, excessive generation of unsaturated bonds can be more reliably suppressed, thereby preventing gelation caused by unsaturated bonds and enabling better control of the polymerization reaction. Furthermore, the lower limit of the reaction time is usually 2 hours or more, and the upper limit is usually 15 hours or less, preferably 10 hours or less. That is, the reaction time is preferably 2 hours or more and 15 hours or less, and particularly preferably 2 hours or more and 10 hours or less.

[0053] <Resin composition> The content of the aliphatic polyester resin (A) in the resin composition is not particularly limited, but from the viewpoint of high-speed moldability and appearance, it is usually 5% by weight or more, preferably 10% by weight or more, more preferably 15% by weight or more, even more preferably 20% by weight or more, and particularly preferably 25% by weight or more. The upper limit is not particularly limited and may be 100% by mass. That is, the content of the aliphatic polyester resin (A) in the resin composition is preferably 5% by weight or more and 100% by weight or less, particularly preferably 10% by weight or more and 100% by weight or less, more preferably 15% by weight or more and 100% by weight or less, even more preferably 20% by weight or more and 100% by weight or less, and even more preferably 25% by weight or more and 100% by weight or less.

[0054] The aliphatic polyester resin (A) is not limited to one type, and a blend of two or more types of aliphatic polyester resins (A) differing in the type and ratio of constituent units, production method, physical properties, etc. may be used.

[0055] [Aliphatic polyester resin (B)] From the viewpoint of high-speed moldability and heat resistance, the resin composition may further contain, as the aliphatic polyester resin (B), an aliphatic polyester resin other than the above-mentioned aliphatic polyester resin (A). For example, the resin composition may contain, as the polyester resin (B) other than the aliphatic polyester resin (A) containing a succinic acid unit and an aliphatic dicarboxylic acid unit having 9 to 36 carbon atoms, an aliphatic polyester resin that does not contain a succinic acid unit and an aliphatic dicarboxylic acid unit having 9 to 36 carbon atoms, or may contain an aliphatic polyester resin that contains one selected from the group consisting of a succinic acid unit and an aliphatic dicarboxylic acid unit having 9 to 36 carbon atoms, but not the other. In particular, from the viewpoint of high-speed moldability and heat resistance, the aliphatic polyester resin (B) is preferably an aliphatic polyester resin containing succinic acid units but not containing aliphatic carboxylic acid units having 9 to 36 carbon atoms. Specifically, for example, it is preferable that the aliphatic polyester resin has aliphatic diol units and aliphatic dicarboxylic acid units as its main structural units, and the aliphatic dicarboxylic acid units contain only succinic acid units or only succinic acid units and adipic acid units. Examples of such aliphatic polyester resins (B) include PBS and PBSA. Note that the content described in the above section "(2) Content of each dicarboxylic acid unit in all polyester resins contained in the resin composition" can be adjusted to satisfy the above preferred range by adjusting the amount of succinic acid units or aliphatic dicarboxylic acid units having 9 to 36 carbon atoms in polyester resins other than the polyester resin (A).

[0056] When the resin composition contains an aliphatic polyester resin (B), the content of the aliphatic polyester resin (B) in the resin composition is not particularly limited, but from the viewpoint of high-speed moldability, it is preferably 1% by weight or more, more preferably 5% by weight or more, even more preferably 10% by weight or more, preferably 90% by weight or less, more preferably 80% by weight or less, and even more preferably 70% by weight or less. That is, the content of the aliphatic polyester resin (B) in the resin composition is preferably 1% by weight or more and 90% by weight or less, particularly preferably 5% by weight or more and 80% by weight or less, and more preferably 10% by weight or more and 70% by weight or less. Furthermore, when the resin composition contains an aliphatic polyester resin (B), the content of the aliphatic polyester resin (A) is 10% by weight or more, more preferably 20% by weight or more, particularly preferably 30% by weight or more, and especially preferably 50% by weight or more, based on the total weight of the aliphatic polyester resin (A) and the aliphatic polyester resin (B). It may also be less than 100% by weight, preferably 99% by weight or less, more preferably 95% by weight or less, even more preferably 90% by weight or less, particularly preferably 80% by weight or less, and especially preferably 70% by weight or less. That is, when the resin composition contains an aliphatic polyester resin (A) and an aliphatic polyester resin (B), the content of the aliphatic polyester resin (A) in the resin composition is preferably 10% by weight or more and less than 100% by weight, particularly preferably 20% by weight or more and 99% by weight or less, more preferably 30% by weight or more and 95% by weight or less, more preferably 50% by weight or more and 90% by weight or less, particularly preferably 50% by weight or more and 80% by weight or less, and even more preferably 50% by weight or more and 70% by weight or less. By the content of the aliphatic polyester resin (A) relative to the total weight of the aliphatic polyester resin (A) and the aliphatic polyester resin (B) in the above range, the appearance of the seal layer surface becomes more excellent.

[0057] The aliphatic polyester resin (B) is not limited to one type, and a blend of two or more types of aliphatic polyester resins (B) differing in the type and ratio of constituent units, production method, physical properties, etc. may be used.

[0058] [Other Resins] The resin composition may contain resins (other resins) other than the aliphatic polyester resin (A) and the optional aliphatic polyester resin (B) as long as the effects of the present invention are not impaired. Examples of other resins include aromatic polyester resins, polycarbonate, polyamide, polystyrene, polyolefin, acrylic resin, amorphous polyolefin, ABS, AS (acrylonitrile styrene), polycaprolactone, polyvinyl alcohol, or synthetic resins such as cellulose ester, polylactic acid, PBAT, PBST, or PBSeT, and other biodegradable resins such as aliphatic aromatic polyesters. One type of other resin may be used alone, or two or more types may be used in combination.

[0059] When the resin composition contains other resins, in order to effectively obtain the effects of including the aliphatic polyester resin (A) as a resin component and further the optional aliphatic polyester resin (B), the content of the other resin is preferably 50 parts by weight or less, more preferably 30 parts by weight or less, and particularly preferably 20 parts by weight or less, per 100 parts by weight of the total of the aliphatic polyester resin (A), the aliphatic polyester resin (B), and the other resins. That is, the content of the other resin in the resin composition is preferably 0 to 50 parts by weight, particularly preferably 0 to 30 parts by weight, and even more preferably 0 to 20 parts by weight, per 100 parts by weight of the total of the aliphatic polyester resin (A), the aliphatic polyester resin (B), and the other resins.

[0060] [Other Components] The resin composition may contain various additives such as inorganic fillers, lubricants, plasticizers, antistatic agents, antioxidants, light stabilizers, UV absorbers, dyes, pigments, hydrolysis inhibitors, crystal nucleating agents, antiblocking agents, light resistance agents, plasticizers, heat stabilizers, flame retardants, release agents, antifogging agents, surface wetting improvers, incineration aids, dispersing aids, various surfactants, or slip agents, as well as fine powders of animal or plant substances such as starch, cellulose, paper, wood flour, chitin / chitosan, coconut shell powder, or walnut shell powder, or mixtures thereof, as "other components." The resin composition may also contain functional additives such as freshness-preserving agents or antibacterial agents. These may be blended in any amount within the range that does not impair the effects of the present invention, and may be used alone or in combination of two or more.

[0061] In order not to impair the physical properties of the resin composition, the content of these other components is usually preferably such that the total amount of the other components is 0.01% by weight or more and 15% by weight or less relative to the total amount of the resin composition.

[0062] [Physical Properties of Resin Composition] The various physical properties that the resin composition constituting the seal layer of the laminate according to the present invention preferably possesses are described below. When the resin composition is composed solely of the aliphatic polyester resin (A) according to the present invention, the various physical properties of the resin composition described below are the same as those of the aliphatic polyester resin (A) described above. (Solid Viscoelasticity) In measuring the solid viscoelasticity of the resin composition, the storage modulus E' measured at a temperature of 100°C and a frequency of 1 Hz according to Japanese Industrial Standards (JIS) K7244-4:1999 is preferably 180 MPa or less. Having the storage modulus E' at or below this value allows for the production of a laminate with excellent heat sealability at low temperatures. For the same reasons, the storage modulus E' is more preferably 150 MPa or less. The lower limit of the storage modulus E' is not particularly limited, but is typically 0 MPa or more. That is, the storage modulus E' of the resin composition is preferably 0 to 180 MPa, and particularly preferably 0 to 150 MPa. The storage modulus E' is measured using a rotational rheometer in accordance with JIS K7244-4:1999. In the examples described below, a rotational rheometer (trade name: ARES-G2; manufactured by TA Instruments) in DMA mode was used. Then, while raising the temperature in the temperature range of 20°C to 130°C at a heating rate of 3°C / min, the sample is subjected to tensile deformation at a frequency of 1 Hz, a strain of 0.1%, and a measurement interval of 1.0 s / point, and the storage modulus E' at each temperature is recorded. Then, the value of the storage modulus E' at a temperature of 100°C is obtained.

[0063] (Melt viscoelasticity) In measuring the melt viscoelasticity of the resin composition, the storage modulus G' measured at a temperature of 80°C and a frequency of 1 Hz according to JIS K7244-10:2005 is preferably 60 MPa or less. When the storage modulus G' is equal to or less than the above value, the anchor effect between the base layer and the seal layer is strengthened, thereby improving adhesion. For the same reason, the storage modulus G' is more preferably 40 MPa or less. The lower limit of the storage modulus G' is not particularly limited, but is usually 0 MPa or more. That is, the storage modulus G' of the resin composition at a temperature of 80°C and a frequency of 1 Hz is preferably 0 to 60 MPa, and particularly preferably 0 to 40 MPa.

[0064] For the same reason, in measuring the melt viscoelasticity of the resin composition, the storage modulus G' measured at a temperature of 60°C and a frequency of 1 Hz according to JIS K7244-10:2005 is preferably 80 MPa or less, and more preferably 70 MPa or less. The lower limit of the storage modulus G' is not particularly limited, but is typically 0 MPa or more. That is, the storage modulus G' of the resin composition at a temperature of 60°C and a frequency of 1 Hz is preferably 0 to 80 MPa, and particularly preferably 0 to 70 MPa. The storage modulus G' at each of the above temperatures (80°C, 60°C) is measured using a rotational rheometer according to JIS K7244-10:2005. In the examples described below, an "ARES-G2" (trade name, manufactured by TA Instruments) was used as the rotational rheometer. The measurement method involves placing a test piece (0.2 g) of the resin composition to be measured on the plate of the rotational rheometer heated to 190°C and melting it under a nitrogen atmosphere. The test piece is then compressed between 8 mm diameter parallel plates to a distance of 0.5 to 2 mm, and any resin that protrudes from the plates is removed. After the temperature reaches 190°C, dynamic viscoelasticity measurement is performed under conditions of a frequency of 1 Hz, a strain of 0.1%, and a measurement interval of 1.0 s / point while cooling at a rate of 1°C / min, and the storage modulus G' is measured in the range of 190 to 30°C. In this way, the storage modulus G' at temperatures of 60°C and 80°C is obtained.

[0065] (Melt Viscosity Ratio) The melt viscosity ratio of the resin composition, expressed by the following formula (2), is preferably 4.0 or more. Melt Viscosity Ratio=η3 / η4 (2) In formula (2), η3 is the melt viscosity ratio at a temperature of 190° C. and a shear rate of 60.8 (sec －１ η4 represents the melt viscosity of the resin composition at a temperature of 190°C and a shear rate of 1216 (sec －１ The melt viscosity ratio of the resin composition at a shear rate of 60.8 (sec) is shown. By having the melt viscosity ratio in the above range, it is possible to suppress the appearance defect of the molten film due to melt fracture or the like, and it is possible to obtain a laminate with an excellent surface appearance of the seal layer. －１ ) is the shear rate applied to the resin composition in the melt flow rate (MFR) measurement, and the shear rate is 1216 (sec －１ ) is the shear rate applied to the resin composition during extrusion molding. The melt viscosities η3 and η4 are measured using a capillary rheometer based on JIS K7199:1999 (Method A). A capillary die with a diameter (inner diameter) of 1 mm and a length of 10 mm is used. The apparent shear rate at a test temperature of 190°C is 60.8 (sec －１ ) and 1216 (sec －１ In the examples described later, a "Capillograph" (trade name, manufactured by Toyo Seiki Seisakusho) was used as the capillary rheometer.

[0066] (Melt Tension) In measuring the melt tension of the resin composition, the average melt tension at a temperature of 190°C, an extrusion speed of 10 mm / min, and a take-up speed of 4 m / min is preferably 20 mN or less, and particularly preferably 18 mN or less. The lower limit of the melt tension is not particularly limited, but is preferably 5 mN or more, and particularly preferably 7 N or more. That is, the melt tension of the resin composition is preferably 5 mN or more and 20 mN or less, and particularly preferably 7 mN or more and 18 mN or less. Having the melt tension of the resin composition within the above range improves the drawdown properties of the molten film, enabling even faster molding of the laminate. The melt tension is determined by measuring the stress when the resin composition is stretched at a constant speed. A capillary rheometer is used for the measurement. For example, in the examples described below, a "Capirograph" (trade name, manufactured by Toyo Seiki Seisakusho) was used as the capillary rheometer. The measurement conditions are as follows: resin temperature 190° C., cylinder extrusion speed 10 mm / min, take-up speed 4 m / min, capillary diameter 1 mm, and capillary length 10 mm.

[0067] (Melt flow rate (MFR)) The melt flow rate (MFR) of the resin composition is a value measured at 190 ° C. and a load of 2.16 kg according to JIS K7210-1:2014, and is usually 0.1 g / 10 min or more and 100 g / 10 min or less, but from the viewpoint of moldability and mechanical strength, it is preferably 40 g / 10 min or less, more preferably 20 g / 10 min or less, preferably 1.0 g / 10 min or more, and more preferably 2.0 g / 10 min or more. That is, the MFR of the resin composition measured at 190 ° C. and a load of 2.16 kg according to JIS K7210-1:2014 is preferably 0.1 g / 10 min or more and 100 g / 10 min or less, particularly preferably 1.0 g / 10 min or more and 40 g / 10 min or less, and even more preferably 2.0 g / 10 min or more and 20 g / 10 min or less. The MFR of the resin composition can be adjusted by the molecular weight of the aliphatic polyester resin (A) constituting the resin composition, etc. That is, the MFR can be reduced by increasing the molecular weight, and the MFR can be increased by decreasing the molecular weight.

[0068] [Method of producing resin composition] The resin composition is produced by a method including a mixing step of mixing the aliphatic polyester resin (A), preferably the aliphatic polyester resin (B), with other resins and other components that are used as needed.

[0069] This mixing step is carried out by mixing the aliphatic polyester resin (A), and the aliphatic polyester resin (B) that may be further contained, other resins, and other components in a predetermined ratio simultaneously or in any order using a mixer such as a tumbler, a V-type blender, a Nauta mixer, a Banbury mixer, a kneading roll, or an extruder, and preferably melt-kneading the mixture.

[0070] The kneader used in the mixing step may be a melt kneader. Although there is no limitation on the type of twin-screw extruder or single-screw extruder, a twin-screw extruder is more preferable for the purpose of achieving melt kneading depending on the properties of the aliphatic polyester resin (A) used and the aliphatic polyester resin (B) that may be contained.

[0071] The temperature during melt-kneading is preferably 120 to 220°C, and more preferably 130 to 180°C. This temperature range makes it possible to shorten the time required for the melting reaction, prevent deterioration in color tone due to resin degradation, and further improve practical physical properties such as impact resistance and moist heat resistance. Furthermore, from the viewpoint of further preventing the same resin degradation as described above, the melt-kneading time should not be unnecessarily long, and is preferably 20 seconds or more and 20 minutes or less, more preferably 30 seconds or more and 15 minutes or less, and it is preferable to set the time so as to satisfy these conditions together with the temperature.

[0072] <Laminate> A laminate according to one embodiment of the present invention has a base layer and a seal layer on at least one surface of the base layer. In the laminate, the mass proportion of the aliphatic polyester resin (A) relative to the total mass of the base layer and the seal layer is preferably 5 to 80 mass%, more preferably 10 to 70 mass%. When the mass proportion of the aliphatic polyester resin (A) is equal to or greater than the lower limit of the above range, sufficient heat sealability can be obtained when used as a packaging material, and when it is equal to or less than the upper limit of the above range, sufficient rigidity can be obtained.

[0073] The total thickness of the laminate is preferably 10 to 300 μm, particularly preferably about 20 to 250 μm, from the viewpoints of biodegradability, thin film properties, mechanical strength, processing stability, and the like.

[0074] [Sealing layer] The sealing layer of the laminate can be obtained by molding the above-mentioned resin composition into a film.The method for molding the resin composition into a film can be, for example, injection molding, extrusion molding, or co-extrusion molding (film molding by inflation method or T-die method), or extrusion lamination molding, heat press molding, blow molding (various blow moldings), thermoforming (vacuum molding, pressure molding), plastic processing, or powder molding (rotational molding).Among these, the method for molding by extrusion molding or inflation molding (inflation method), T-die method, or extrusion lamination molding is particularly preferred because the effects of the present invention are significantly exhibited.

[0075] More specifically, for example, a method can be mentioned in which a film-like, sheet-like or cylindrical product extruded to a predetermined thickness from a T-die, I-die, round die or the like is cooled and solidified by a cooling roll, water, compressed air, etc. In this case, it is also possible to form a laminated film by laminating several types of compositions within a range that does not impair the effects of the present invention.

[0076] In the case of inflation molding, conditions such as bubble internal pressure, heating temperature, bubble diameter, cooling rate, and take-up speed can be conventionally used. For example, the tear strength of the film can be adjusted by setting the blow ratio to, for example, 1.1 to 10 times, preferably 2 to 5 times. In addition, the suitability for inflation molding can be determined visually by bubble stability or frost line height, etc. For example, the more stable the bubble is, the more preferable it is, and the more symmetrical the bubble shape is. It is preferable that the frost line height is not too high. By optimizing the frost line height, the tubular film can be prevented from becoming difficult to solidify, preventing film blocking and deterioration of opening. It also prevents the bubble from contacting the air ring or die. Therefore, it is preferable to set the frost line height within a range appropriate for the equipment, raw materials used, and processing conditions.

[0077] The resin temperature in the die is usually 100°C or higher so that the melt viscosity does not become too high and the extrusion rate per power of the extruder is appropriate. On the other hand, it is usually 280°C or lower so that resin deterioration does not adhere to the die and get mixed into the obtained film. The resin temperature in the die is preferably 110 to 270°C, more preferably in the range of 120 to 265°C.

[0078] The film obtained by such inflation molding, i.e., the sealing layer, may have a single layer structure or a laminated structure. The thickness of the film obtained by inflation molding, i.e., the sealing layer, is usually 6 to 100 μm, preferably 10 to 50 μm.

[0079] In the case of T-die molding, the resin temperature inside the die is usually 110°C or higher so that the melt viscosity does not become too high and the extrusion rate per power of the extruder is appropriate. On the other hand, it is usually 280°C or lower so that resin deterioration does not adhere to the die and get mixed into the obtained film. The resin temperature inside the die is preferably 120 to 250°C, more preferably 130 to 220°C.

[0080] Furthermore, the extruded molten resin is desirably cooled quickly to prevent blocking during winding, and is usually cooled using an electrostatic contact or touch roll casting roll. In this case, the surface temperature of the casting roll is usually controlled to 15 to 70°C, preferably 20 to 60°C. Furthermore, when the sheet thickness is 1 mm or more, it is desirable to use a multistage cooling roll. Other commonly known molding conditions can be used.

[0081] The film obtained by T-die molding, i.e., the sealing layer, may have a single layer structure or a laminated structure. The thickness of the film obtained by T-die molding, i.e., the sealing layer, is usually 3 to 200 μm, preferably 5 to 100 μm.

[0082] The film-like molded article obtained by the inflation method or T-die method may then be uniaxially or biaxially stretched by a roll method, a tenter method, a tubular method, or the like. When stretching, the stretching temperature is usually in the range of 30°C to 110°C, and the stretching ratio is in the range of 0.6 to 10 times in both the longitudinal and transverse directions. After stretching, the film may be heat-treated by a method of blowing hot air, irradiating with infrared rays, irradiating with microwaves, or contacting with a heat roll, or the like.

[0083] [Substrate Layer] The substrate layer is preferably a fiber or a film, and specific examples thereof include paper, paperboard, cotton nonwoven fabric, rayon nonwoven fabric, polylactic acid film, cellulose nitrate film, cellulose acetate film, cellulose film, polyglycolic acid film, and polyethylene terephthalate film. Among these, from the viewpoint that the resulting laminate is biodegradable as a whole and can form an environmentally friendly packaging material, the substrate layer is preferably biodegradable. Specifically, the substrate layer preferably contains a plant-derived component, and more preferably is composed of a plant-derived component. Specific examples include paper, paperboard, pulp nonwoven fabric, cotton nonwoven fabric, rayon nonwoven fabric, polylactic acid film, and cellulose film, and paper, paperboard, polylactic acid film, and cellulose film are particularly preferred. Furthermore, composite films can also be used that are biodegradable by blending starch, chitosan, or the like with cellulose acetate or regenerated cellulose, which are not themselves biodegradable.

[0084] Examples of paper substrates include wrapping paper such as kraft paper or pure white roll paper; printing and information paper such as construction paper, fine paper, medium-quality paper, glassine paper, parchment, art paper, or coated paper; processed base paper such as cup base paper or cardboard base paper; paperboard such as Kent paper, Manila cardboard, or coated cardboard; and barrier paper provided with oxygen barrier properties or water vapor barrier properties by a coating agent such as polyvinyl alcohol (PVOH). Nonwoven fabrics such as cotton nonwoven fabrics and rayon nonwoven fabrics are also included in the paper substrate. The basis weight (JIS P8124:2011) of these paper substrates varies depending on the paper quality, but is usually 10 to 1,000 g / m ２ and particularly 30 to 700 g / m ２ It is preferable that:

[0085] One method for improving the dry strength of paper substrates is to internally add dry strength agents such as polyacrylamide, cationic starch, or amphoteric starch. The amount of dry strength agent added is typically 0.01 to 0.3% by mass based on the bone-dry pulp. Here, "internal addition" refers to adding an additive to the pulp slurry before papermaking. Another method involves increasing the beating degree of the pulp before papermaking to achieve a CSF of approximately 450 to 600 ml. Here, "CSF" refers to the Canadian Standard Freeness commonly used in the papermaking industry. Another method involves increasing the amount of softwood bleached kraft pulp (NBKP) added to the paper substrate.

[0086] Furthermore, because the paper substrate is hydrophilic, when the laminate comes into contact with water, water may penetrate from the edge of the laminate, causing the substrate layer to swell and become blistered or wrinkled, or the substrate layer may be broken down and peeled off. Therefore, for applications requiring water resistance, it is preferable to improve the sizing degree or wet strength of the paper substrate.

[0087] In paper substrates, methods for improving the sizing degree include the internal addition of an internal sizing agent such as alkyl ketene dimer. The amount of internal sizing agent added is usually 0.1 to 0.5% by mass based on the bone-dry pulp. In this case, it is also preferable to use aluminum sulfate in combination. Furthermore, methods for improving wet strength include the internal addition of an internal wet strength agent such as polyamide polyamine, polyamide polyamine epichlorohydrin modified product, or polyethylene imine epichlorohydrin modified product. The amount of internal wet strength agent added is usually 0.1 to 0.5% by mass based on the bone-dry pulp.

[0088] Paper and paperboard typically contain fillers, commonly referred to as "fillers." In order to improve the whiteness and opacity of the laminate, it is preferable to incorporate heavy calcium carbonate, titanium oxide, barium sulfate, or the like, either alone or in combination, into the substrate. The amount of these fillers incorporated is typically 1 to 30% by mass relative to the paper substrate. Other fillers may be selected and used as needed, including inorganic fillers such as talc, kaolin, calcined kaolin, clay, diatomaceous earth, magnesium carbonate, aluminum hydroxide, magnesium sulfate, silica, aluminosilicates, and bentonite, as well as organic fillers such as polystyrene particles and urea-formaldehyde resin particles. To increase the opacity of the laminate, graphite or carbon black may be incorporated into the substrate layer, or the surface of the substrate layer may be printed in black.

[0089] Nonwoven fabrics can also be used as the substrate layer. Specific examples include "Benliese" (registered trademark) manufactured by Asahi Kasei Corporation, which is a hydroentangled nonwoven fabric made from cotton linters, "Kinocloth" (registered trademark) manufactured by Oji Kinocloth Co., Ltd., which is an airlaid nonwoven fabric made from pulp, "Piros" (registered trademark) manufactured by Omikenshi Co., Ltd., which is a spunlaced nonwoven fabric made from rayon, "Kuraflex" (registered trademark) manufactured by Kuraray Co., Ltd., which is a hydroentangled nonwoven fabric made from rayon, "Terramac" (registered trademark) manufactured by Unitika Ltd., which is a spunbonded nonwoven fabric made from polylactic acid, and "Hibon" (registered trademark) manufactured by Shinwa Co., Ltd.

[0090] Films containing plant-derived components can also be used as the substrate layer. Specific examples include cellulose acetate films such as "Cellgreen PC-A" (registered trademark) manufactured by Daicel Chemical Industries, Ltd. and "Lunare ZT" (registered trademark) manufactured by Nippon Shokubai Co., Ltd., cellulose films such as "NatureFlex" (registered trademark) NP, NPU, NK, and NKR NE series manufactured by Futamura Chemical Co., Ltd., modified starch such as "Plantic" (registered trademark) manufactured by Kuraray Co., Ltd., "Materbee" (registered trademark) manufactured by Novamont Co., Ltd., a blend film of starch and synthetic biodegradable polymer, "Dron CC" (trade name) manufactured by Aicello Chemical Co., Ltd., a blend film of chitosan, cellulose, and starch, "Kuredux" (registered trademark) manufactured by Kuraray Co., Ltd., a polyglycolic acid film, and "Ecologe" (registered trademark) manufactured by Mitsubishi Chemical Corporation, a PLA film.

[0091] Furthermore, when forming a seal layer on at least one surface of the base layer to form a laminate, methods such as dry lamination or non-solvent lamination in which a film, i.e., the seal layer, is bonded to the base layer via an adhesive, or extrusion lamination in which the seal layer is extruded from a T-die in the form of a thin film and applied to at least one surface of the base layer can be used.

[0092] [Other Layers] The laminate may be formed by laminating and integrating a substrate layer and a seal layer made of a resin composition, but may also have other layers as needed. The other layers may be any layers that do not impair the object of the present invention and are not particularly limited, but examples thereof include a printing layer, an adhesive layer, etc.

[0093] <Applications> The laminate described above has excellent high-speed formability and appearance while being degradable in the natural environment, and therefore can be suitably used in a wide range of applications, particularly disposable applications, such as packaging materials, in particular food packaging materials, food containers, pharmaceutical packaging materials, packaging materials for liquids, powders, or solids such as miscellaneous goods, agricultural materials, or construction materials. Specific preferred uses include, for example, agricultural mulch film, tunnel film, greenhouse film, sunshade, weed control sheet, ridge sheet, germination sheet, forestry fumigation sheet, binding tape containing flat yarn or the like, diaper back sheet, packaging sheet, shopping bag, plastic bag, garbage bag, draining bag, compost bag, oily food packaging, dried food packaging, processed livestock product packaging, processed seafood product packaging, beverage and liquid food packaging, dried confectionery packaging, snack food packaging, instant noodle packaging, retort food packaging, chilled and frozen food packaging, packaging for black tea, green tea, coffee, etc., food cups, food trays, supplement packaging, cosmetic packaging, electronic component packaging, optical component packaging, etc.

[0094] Specific embodiments of the present invention will be described in more detail below using examples, but the present invention is not limited to the following examples as long as the gist of the invention is not exceeded. Note that the values ​​of various production conditions and evaluation results in the following examples represent preferred upper or lower limit values ​​in the embodiments of the present invention, and preferred ranges may be defined by a combination of the above-mentioned upper or lower limit values ​​and the values ​​in the following examples or values ​​between the examples.

[0095] [Raw Materials Used] The raw materials used in the Examples and Comparative Examples were polymerized resins or commercially available products as follows. In the following, "PBS" stands for "polybutylene succinate" and "PBSA" stands for "polybutylene succinate / adipate."

[0096] [Production Example] Aliphatic Polyester Resin A-1 A reaction vessel equipped with a stirrer, a nitrogen inlet, a heater, a thermometer, and a pressure reduction port was charged with the following raw materials: 57.8 parts by weight of succinic acid, 12.3 parts by weight of sebacic acid, 64.4 parts by weight of 1,4-butanediol, 0.125 parts by weight of trimethylolpropane, and 0.60 parts by weight of catalyst solution. The molar ratio of succinic acid to sebacic acid was 89:11, and the ratio of the molar amount of 1,4-butanediol to the total molar amount of succinic acid and sebacic acid was 1.30.

[0097] While stirring the contents of the vessel, nitrogen gas was introduced into the vessel, and the system was substituted by vacuum replacement to create a nitrogen atmosphere. Next, the raw materials were dissolved at 160°C. After confirming that the raw materials were completely dissolved and the temperature of the distillation section reached 50°C, the temperature was raised from 160 to 230°C over 1 hour while stirring the system, and the esterification reaction was continued at 230°C under normal pressure for 1 hour. Five minutes before the end of the esterification reaction, a catalyst solution was added. After the esterification reaction, the temperature was raised from 230°C to 250°C over 30 minutes, and at the same time, 0.07 x 10 ３ The pressure was reduced to a pressure of 100 Pa or less, and polymerization was continued while maintaining the heated and reduced pressure state. The polymerization was terminated when a predetermined viscosity was reached, thereby obtaining an aliphatic polyester resin A-1 (amount of succinic acid units based on the total amount of dicarboxylic acid units: 89 mol %, amount of sebacic acid units: 11 mol %, MFR: 5.0 g / 10 min, melting point: 102°C).

[0098] Aliphatic Polyester Resin A-2 Aliphatic polyester resin A-2 (amount of succinic acid units relative to total dicarboxylic acid units: 74 mol%, amount of sebacic acid units: 26 mol%, MFR: 5.0 g / 10 min, melting point: 85° C.) was produced in the same manner as in Production Example for Aliphatic Polyester Resin A-1, except that 44.9 parts by weight of succinic acid, 27.1 parts by weight of sebacic acid, 60.2 parts by weight of 1,4-butanediol, 0.125 parts by weight of trimethylolpropane, and 0.60 parts by weight of catalyst solution were used and the molar ratio of succinic acid to sebacic acid was changed to 74:26.

[0099] PBS: "BioPBS (registered trademark) FZ91PM" manufactured by PTTMCC Biochem (amount of succinic acid units in total dicarboxylic acid units: 100 mol%, MFR: 5.0 g / 10 min, melting point: 115°C) PBSA: "BioPBS (registered trademark) FD92PM" manufactured by PTTMCC Biochem (amount of succinic acid units in total dicarboxylic acid units: 74 mol%, amount of adipic acid units: 26 mol%, MFR: 5.0 g / 10 min, melting point: 89°C)

[0100] [Evaluation Methods] The methods for evaluating various physical properties and characteristics in the examples and comparative examples are as follows.

[0101] (1) Method for Evaluating Physical Properties of Resin Compositions (Melt Flow Rate (MFR)) Based on JIS K7210-1:2014, measurement was performed using a melt indexer at 190°C and a load of 2.16 kg. The unit is g / 10 min. The MFRs of the aliphatic polyester resins A-1, A-2, PBS, and PBSA were also measured by the same method.

[0102] (Melt Viscosity) Based on JIS K7199:1999, the melt viscosity of the resin composition was measured using a capillary rheometer (trade name: Capilograph, manufactured by Toyo Seiki Seisakusho) under the conditions of a temperature of 190°C, a capillary diameter of 1 mm, a capillary length of 10 mm, and shear rates of 60.8, 121.6, 608, and 1216 [1 / sec].

[0103] (Melt Tension) Measurement was carried out using a capillary rheometer (trade name: Capilograph, manufactured by Toyo Seiki Seisakusho) at a temperature of 190° C., a capillary diameter of 1 mm, a capillary length of 10 mm, a cylinder extrusion speed of 10 mm / min, and a take-up speed of 4 m / min.

[0104] (Storage Modulus (Solid Viscoelasticity)) The storage modulus E' was measured using a rotational rheometer (trade name: ARES-G2, manufactured by TA Instruments) in DMA mode. The specimen was heated at a rate of 3°C / min over a temperature range from room temperature (20 to 30°C) to 130°C, while being subjected to tensile deformation at a frequency of 1 Hz, a strain of 0.1%, and a measurement interval of 1.0 s / point, and the storage modulus E' was measured at each temperature. (Storage Modulus (Melt Viscoelasticity)) The storage modulus G' was measured using a rotational rheometer (trade name: ARES-G2, manufactured by TA Instruments) in accordance with JIS K7244-10:2005. The test piece was placed on the plate of a viscoelasticity measuring device heated to a measurement start temperature of 190°C, and heated and melted in a nitrogen atmosphere. Thereafter, the sample was compressed between parallel plates with a diameter of 8 mm to a distance of 0.5 to 2 mm, and any resin protruding from the plates was removed. After the temperature reached 190°C, the sample was cooled at a rate of 1°C / min. Dynamic viscoelasticity measurements were then performed under conditions of a frequency of 1 Hz, a strain of 0.1%, and a measurement interval of 1.0 s / point, to measure the storage modulus G' in the range of 190 to 30°C.

[0105] (2) Evaluation method of laminate (1: Surface appearance of seal layer) The state of the surface appearance of the seal layer was evaluated visually. The evaluation criteria were as follows: Rank A (good): The surface is in a normal state with no irregularities or roughness due to melt fracture or the like, and no FE (fish eye), foreign matter, or air bubbles. Rank B (fair): The surface is partially irregular and rough due to melt fracture or the like, or there are some FE (fish eye) or foreign matter, but it is within an acceptable range. Rank C (unacceptable): The entire surface is irregular and rough due to melt fracture or the like, or there are FE (fish eye), foreign matter, or air bubbles, and the secondary processability is poor.

[0106] (2: High-speed formability) The state of the molten film was checked while passing the molten film through a cooling roll under the same extrusion conditions and gradually changing the take-up speed. The evaluation criteria were as follows. Rank A (excellent): When molded at 15 m / min, there was no shaking or holes in either the center or edges of the film, and high-speed molding was possible without any sticking to the cooling roll, and the surface and edges of the film were in a clean state. Rank B (good): When molded at 15 m / min, there was no shaking or holes in either the center or edges of the film, and high-speed molding was possible, and the surface and edges of the film were in a clean state. Rank C (unacceptable): When molded at 15 m / min, the edges of the molten film were hard and cut, or a hole was made in the center of the molten film, preventing uniform film lamination and making high-speed molding impossible.

[0107] (3: Heat sealability between seal layers) Heat seal strength was determined in accordance with the heat seal strength test (7-4) specified in JIS Z 1707:2019. A flat portion of the resin layer with a film thickness of 30 μm was used as the test piece, cut into a length and width of 15 cm, heat-sealed one end with a heat sealer so that the resin layer portion was aligned, and cut into a 15 mm wide strip. Heat sealing was performed using a single-sided heating bar sealer with a seal bar width of 5 mm, at a sealing temperature of 120°C, a sealing pressure of 0.2 MPa, and a sealing time of 1 second. The heat seal strength was measured using a Tensilon universal testing machine at a peel angle of 180° and a tensile speed of 300 mm / min, and the load at peel or break (N / 15 mm) was measured. The evaluation criteria were as follows: Rank A (Excellent): 12N or more Rank B (Good): 10N or more but less than 12N Rank C (Unacceptable): Less than 10N

[0108] (4: Adhesion between substrate and seal layer) The adhesive strength between the seal layer and the paper substrate was shown as the strength when peeled at a peel angle of 180°, a peel speed of 300 mm / min, and a test piece width of 25 mm, and the state of peeling between the resin layer and the paper was also observed. Rank A: No interfacial peeling occurred, and cohesive failure of the paper was observed. Rank B: The adhesive strength between the resin and the paper substrate was weak, and interfacial peeling was observed.

[0109] (5: Biodegradation test in seawater) After storing the sheet in seawater collected from Yokkaichi Port in Yokkaichi City, Mie Prefecture for 3 months at a temperature of 28±2°C, weight measurements were carried out and biodegradability in seawater was evaluated according to the following criteria. The degree of decomposition was calculated using the following formula: Decomposition degree (%) = 100 - (sample weight after 3 months / sample weight before test) x 100 Rank A (excellent): Decomposition degree is 60% or more Rank B (good): Decomposition degree is 50% or more and less than 60% Rank C (passable): Decomposition degree is 10% or more and less than 50% Rank D (unacceptable): Decomposition degree is less than 10%

[0110] [Examples 1-4, Comparative Examples 1-2] Pellets of aliphatic polyester resin (A) shown in Table 1, or pellets of aliphatic polyester resin (A) and pellets of aliphatic polyester resin (B) dry blended in the ratios shown in Table 1, were introduced into a single-layer T-die molding machine (die width 300 mm, screw diameter 50 mmφ, L / D 28) equipped with a substrate feeder and a take-up machine to produce a laminate. The extrusion conditions were as follows: extruder cylinder set temperature C1 (hopper side temperature) 200 ° C, C2 (die side temperature) 250 ° C, die resin temperature (end 250 ° C, center 250 ° C, end 250 ° C). The extruder rotation speed was 15 rpm, the air gap width was 120 mm, and a semi-matt roll with a radius of 150 mm was used as a cooling roll, and the take-up speed was 20 m / min. The cooling temperature at this time was set to 30 ° C.

[0111] The substrate is a corona-treated cup base paper (250 g / m ２ A laminate was produced by using a substrate (non-laminate type) that was unwound at a low speed and brought into contact with the molten film of the resin composition, and then sandwiching both the substrate and the molten resin between the surfaces of a cooling roll with a nip roll at a pressure of 0.4 MPa, and then increasing the take-up speed to a predetermined speed.

[0112] The obtained laminate was subjected to the above-mentioned laminate evaluations 1 to 5. The results of the physical property evaluations of the resin composition and the evaluation results of the laminate are shown in Table 1.

[0113]

[0114] From Table 1, it can be seen that the laminate according to one embodiment of the present invention had excellent high-speed formability and appearance, as well as excellent adhesion between the substrate and the sealing layer, heat sealability between the sealing layers, and marine biodegradability.

Claims

1. A laminate having a base layer and a seal layer on at least one surface of the base layer, wherein the seal layer is made of a resin composition containing an aliphatic polyester-based resin (A), and the aliphatic polyester-based resin (A) contains, as main structural units, a repeating structural unit A1 derived from an aliphatic diol and a repeating structural unit A2 derived from an aliphatic dicarboxylic acid, and the repeating structural unit A2 derived from the aliphatic dicarboxylic acid contains at least a repeating structural unit A21 derived from succinic acid and a repeating structural unit A22 derived from an aliphatic dicarboxylic acid having 9 to 36 carbon atoms.

2. The laminate described in claim 1, wherein the aliphatic polyester resin (A) has a content of the repeating structural unit A21 derived from succinic acid in the repeating structural unit A2 derived from the aliphatic dicarboxylic acid of 50 mol % or more and 99 mol % or less.

3. The laminate described in claim 1, wherein the aliphatic polyester resin (A) has a content of repeating structural unit A22 derived from an aliphatic dicarboxylic acid having 9 to 36 carbon atoms in the repeating structural unit A2 derived from the aliphatic dicarboxylic acid of 1 mol % or more and 50 mol % or less.

4. The laminate according to claim 1, wherein the repeating structural unit A22 derived from an aliphatic dicarboxylic acid having 9 to 36 carbon atoms includes a repeating structural unit derived from an aliphatic dicarboxylic acid having 9 to 13 carbon atoms.

5. The laminate described in claim 1, wherein the content of the repeating structural unit A1 derived from the aliphatic diol is 25 mol % or more and 75 mol % or less, based on the number of moles of all structural units of the aliphatic polyester resin (A).

6. The laminate described in claim 1, wherein the content of the repeating structural unit A2 derived from the aliphatic dicarboxylic acid is 25 mol % or more and 75 mol % or less, based on the number of moles of all structural units of the aliphatic polyester resin (A).

7. The laminate according to claim 1, wherein the resin composition further contains an aliphatic polyester resin (B) other than the aliphatic polyester resin (A).

8. The laminate according to claim 7, wherein the aliphatic polyester resin (B) contains, as main structural units, a repeating structural unit B1 derived from an aliphatic diol and a repeating structural unit B2 derived from an aliphatic dicarboxylic acid, and the repeating structural unit B2 derived from an aliphatic dicarboxylic acid contains a repeating structural unit derived from succinic acid.

9. The laminate according to claim 7, wherein the content of the aliphatic polyester resin (A) is 30% by weight or more and less than 100% by weight based on the total weight of the aliphatic polyester resin (A) and the aliphatic polyester resin (B).

10. The laminate according to claim 1, wherein the ratio of the total number of moles of repeating structural units derived from aliphatic dicarboxylic acids having 9 to 36 carbon atoms contained in the resin composition to the total number of moles of repeating structural units derived from all aliphatic dicarboxylic acids contained in the resin composition is 1 mol % or more and 50 mol % or less.

11. The laminate according to claim 1, wherein the ratio of the total number of moles of repeating structural units derived from aliphatic dicarboxylic acids having 9 to 36 carbon atoms contained in the resin composition to the total number of moles of repeating structural units derived from all aliphatic dicarboxylic acids contained in the resin composition is 5 mol % or more and 30 mol % or less.

12. The laminate according to claim 1, wherein the aliphatic polyester resin (A) has a storage modulus E' of 180 MPa or less at 100°C, as determined by solid viscoelastic measurement in accordance with JIS K7244-4:1999 at a frequency of 1 Hz, a temperature range of 20°C to 130°C, and a heating rate of 3°C / min.

13. The laminate according to claim 1, wherein the aliphatic polyester resin (A) has a storage modulus G' of 60 MPa or less at a temperature of 80° C., as determined by melt viscoelasticity measurement at a frequency of 1 Hz in accordance with JIS K7244-10:2005.

14. The laminate according to claim 1, wherein the aliphatic polyester resin (A) has a storage modulus G' of 80 MPa or less at 60°C as determined by melt viscoelasticity measurement at a frequency of 1 Hz in accordance with JIS K7244-10:2005.

15. The laminate described in claim 1, wherein the aliphatic polyester resin (A) has a melt tension of 20 mN or less at a temperature of 190°C, an extrusion speed of 10 mm / min, and a take-up speed of 4 m / min.

16. The laminate according to claim 1, wherein the aliphatic polyester resin (A) has a melt viscosity ratio of 4.0 or more, as expressed by the following formula (1): Melt viscosity ratio = η1 / η2 (1) (In formula (1), η1 is the melt viscosity ratio at a temperature of 190°C and a shear rate of 60.8 (sec －１ ) represents the melt viscosity of the aliphatic polyester resin (A) at a temperature of 190° C. and a shear rate of 1216 (sec －１ ) shows the melt viscosity of the aliphatic polyester resin (A) at 17. The laminate according to claim 1, wherein the resin composition has a storage modulus E' at a temperature of 100°C, as measured in accordance with JIS K7244-4:1999, at a frequency of 1 Hz, in a temperature range of 20°C to 130°C, and at a heating rate of 3°C / min, of 180 MPa or less.

18. The laminate according to claim 1, wherein the resin composition has a storage modulus G' at a temperature of 80° C., as measured by melt viscoelasticity measurement at a frequency of 1 Hz in accordance with JIS K7244-10:2005, of 60 MPa or less.

19. The laminate according to claim 1, wherein the resin composition has a storage modulus G' at a temperature of 60° C., as measured by solution viscoelasticity measurement at a frequency of 1 Hz in accordance with JIS K7244-10:2005, of 80 MPa or less.

20. The laminate described in claim 1, wherein the resin composition has a melt tension of 20 mN or less at a temperature of 190°C, an extrusion speed of 10 mm / min, and a take-up speed of 4 m / min.

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