Resin composition and molded article

Abstract

The objective is to provide a resin composition that begins to decompose upon contact with an ionic aqueous solution such as seawater, and a molded article using the same. [Solution] A resin composition comprising a composite in which an ionic nitrogen compound represented by formula (I) and having a molecular weight of less than 10,000 is adsorbed on a carrier by non-covalent bonds, and a resin. JPEG2026068704000007.jpg30170

Description

[Technical Field]

[0001] The present invention relates to a resin composition and a molded article using the resin composition. More specifically, it relates to a biodegradable resin composition and a molded article using the resin composition. [Background technology]

[0002] In modern society, plastics are used in a wide range of everyday applications, such as packaging materials, home appliance materials, and building materials, due to their lightness, electrical insulation properties, moldability, and durability. Examples of plastics used in these applications include polyethylene, polypropylene, polystyrene, polyvinyl chloride, and polyethylene terephthalate. However, molded products made from these plastics are difficult to decompose in the natural environment and tend to remain in the soil even when buried after use. Furthermore, incineration can generate harmful gases that damage incinerators. In recent years, from the perspective of preventing environmental pollution, there has been a growing demand worldwide for products that can be composted in ordinary households (home compostable products).

[0003] As a means of solving the above-mentioned problems, research has been conducted on biodegradable materials that are broken down into carbon dioxide and water by microorganisms in compost. Representative examples of biodegradable materials include polylactic acid (hereinafter sometimes abbreviated as "PLA") (Non-Patent Literature 1).

[0004] In recent years, marine pollution caused by plastic waste dumped into the ocean has become a major social problem. Therefore, the development of highly biodegradable plastics for marine environments is expected to help solve the problem of plastic pollution in the oceans. However, the aforementioned biodegradable plastics mainly focus on biodegradation in compost, and sufficient research has not been conducted on plastics that are highly biodegradable in seawater where there are few biodegrading bacteria. On the other hand, when using plastics, it is generally required that they be resistant to degradation, and high hydrolysis resistance is considered desirable. Therefore, practically speaking, the development of plastics that combine biodegradability and hydrolysis resistance is desirable, but since biodegradability and hydrolysis resistance are contradictory properties in terms of plastic decomposition, it was thought that developing a plastic that possesses both properties would be difficult.

[0005] Non-patent document 2 discloses a film in which protease K (enzyme) is physically immobilized and captured within the pores of a porous carrier and kneaded with poly(L-lactic acid) (hereinafter sometimes referred to as "PLLA"). In Non-patent document 2, a non-charged porous polyacrylamide is used as the porous carrier. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Polymer Degradation and Stability 98 (2013) 1089-1096 [Non-Patent Document 2] Biomacromolecules 2020, 21, 3301-3307 [Overview of the project] [Problems that the invention aims to solve]

[0007] The technology disclosed in Non-Patent Document 2 above is thought to involve the release of enzymes from the porous carrier when scratches are made on the film surface and the film comes into contact with moisture, and the degradation of PLLA is initiated by the action of these enzymes. However, in the technology disclosed in Non-Patent Document 2, even during use, if scratches occur on the film surface, contact with moisture will cause the film to start decomposing, and there is a risk that the functions and performance of the film will deteriorate. That is, in the technology disclosed in Non-Patent Document 2, there is a problem that it is difficult to control the starting point of decomposition, for example, decomposition only starts when it accidentally comes into contact with seawater discarded in the ocean. In addition, there were problems that enzymes were difficult to mass-produce and became too expensive to be used as general-purpose products. Furthermore, enzymes are generally heat-sensitive, and there is a risk of reduction in enzyme activity due to heat during the molding process. Depending on the molding conditions, there is also a risk that sufficient decomposition performance cannot be obtained even when in contact with water.

[0008] Therefore, an object of the present invention is to provide a resin composition that starts decomposing upon contact with an ionic aqueous solution such as seawater, and a molded article using the same.

Means for Solving the Problems

[0009] In view of the above circumstances, the present inventors conducted intensive studies and as a result, found that a resin composition containing a composite in which an ionic nitrogen compound is adsorbed to a carrier by non-covalent bonding and a resin can solve the above problems, and completed the present invention. That is, the gist of the present invention is as follows.

[0010] [1] A resin composition comprising a composite in which an ionic nitrogen compound represented by the formula (I) and having a molecular weight of less than 10,000 is adsorbed to a carrier by non-covalent bonding, a resin, and.

Chemical formula

[10] The resin composition according to [9], wherein the polyester resin comprises an aliphatic diol unit.

[11] The resin composition according to [9], wherein the polyester resin comprises an aliphatic dicarboxylic acid unit.

[12] A molded article obtained using any one of the resin compositions described in [1] to

[11] . [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a resin composition and a molded article that begin to decompose upon contact with an ionic aqueous solution such as seawater. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described in detail below. The present invention is not limited to the following description and can be modified and implemented as appropriate without departing from the spirit of the invention. In this specification, when a "~" is used to enclose numerical values ​​or physical properties, it is intended to include the values ​​before and after it.

[0013] The present invention will be described in detail below, but the description of the constituent elements described below is just one example (representative example) of an embodiment of the present invention, and the present invention is not limited to these contents, and can be implemented in various ways within the scope of its gist.

[0014] [Resin composition] One embodiment of the present invention is A complex in which an ionic nitrogen compound represented by formula (I) and having a molecular weight of less than 10,000 is adsorbed on a carrier by non-covalent bonds, resin and It is a resin composition containing [the specified ingredient]. The resin composition according to this embodiment may be a biodegradable resin composition depending on its composition, and it is preferable that it be a biodegradable resin composition. Hereinafter, the term "this resin composition" may include biodegradable resin compositions. In this specification, "biodegradability" means the property of a resin being broken down into low molecular weight molecules such as oligomers and monomers by hydrolysis or other means through the action of microorganisms, and then further broken down into water and carbon dioxide.

[0015] The resin compositions according to this embodiment will be described in detail below, using biodegradable resin compositions as an example. The resin composition according to this embodiment can be biodegraded in any environment, as long as the resin is biodegraded. In particular, seawater has a small amount of microorganisms, a limited variety of microorganisms, and few nutrients, making it difficult for resins to biodegrade. However, the resin composition according to this embodiment maintains biodegradation accelerators and ionic nitrogen compounds that serve as nutrients for microorganisms in the resin composition and in the molded articles obtained using the resin composition, so it can exhibit sufficient biodegradability even in the ocean. The inventors have found that nitrogen is a particularly deficient nutrient in seawater, and that using low-molecular-weight nitrogen compounds that are easily taken up by microorganisms in seawater is effective in promoting decomposition. In the resin composition according to this embodiment, the composite material contains an ionic nitrogen compound adsorbed onto a carrier by non-covalent bonds. Therefore, external stimuli easily dissociate the bond between the two, releasing the ionic nitrogen compound from the carrier. Consequently, upon contact with an ionic aqueous solution such as seawater, the ionic nitrogen compound is released from the carrier of the composite material, rapidly taken up by microorganisms, and can exert its function as a decomposition accelerator. Furthermore, unlike enzymes, the above-mentioned ionic nitrogen compounds are less susceptible to deactivation by heat. Therefore, the resin composition according to this embodiment exhibits excellent thermal stability, and biodegradability can be promoted even when the resin composition is manufactured at a higher temperature or when the resin composition is molded at a high temperature to form a molded body. On the other hand, before contact with an ionic aqueous solution such as seawater, the ionic nitrogen compounds exist adsorbed onto the carrier, so the ionic nitrogen compounds are not released. As a result, the resin does not decompose, and the function and performance of the molded product can be maintained. As described above, the resin composition according to this embodiment can promote biodegradation even in environments that are difficult to biodegrade, such as the ocean. Therefore, the resin composition according to this embodiment and the molded articles obtained using it exhibit high biodegradability even in seawater.

[0016] <Complex (specific complex)> The resin composition according to this embodiment includes a composite (hereinafter also referred to as a specific composite) in which an ionic nitrogen compound represented by formula (I) and having a molecular weight of less than 10,000 is adsorbed on a support by non-covalent bonds.

[0017] In the above-mentioned specific composite, the ionic nitrogen compound is adsorbed onto the carrier by non-covalent bonds. Non-covalent bonds include intermolecular forces, specifically ionic bonds, hydrophobic bonds, hydrogen bonds, van der Waals forces, and dipole interactions. Among these, ionic bonds or hydrogen bonds are preferred, and ionic bonds are more preferred. Since ionic bonds are not as strong as covalent bonds, when the above-mentioned specific composite comes into contact with seawater, it can dissociate and easily release the ionic nitrogen compound. Furthermore, under normal use conditions, the ionic nitrogen compound and the carrier are adsorbed by ionic bonds, so the ionic nitrogen compound is not released, and the decomposition of the resin by the ionic nitrogen compound does not begin. Although hydrogen bonds and van der Waals forces are weaker than ionic bonds, these bonds may be used to adsorb the ionic nitrogen compound onto the carrier depending on the purpose.

[0018] The content of the specific composite in the resin composition is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, even more preferably 1.0% by mass or more, particularly preferably 3.0% by mass or more, and most preferably 4.0% by mass or more. The upper limit of the content of the specific composite is preferably 30.0% by mass or less, more preferably 20.0% by mass or less, even more preferably 10.0% by mass or less, particularly preferably 7.5% by mass or less, and most preferably 6.0% by mass or less. Setting the content above the lower limit tends to result in a significant biodegradation-promoting effect, while setting it below the upper limit tends to maintain good mechanical properties.

[0019] The following describes the components of each specific complex.

[0020] <<Ionic Nitrogen Compounds>> Ionic nitrogen compounds are ionic nitrogen compounds represented by formula (I) with a molecular weight of less than 10,000.

[0021] [ka] (In the formula, R, R', R'', and R''' each independently represent a hydrogen atom or a monovalent organic group which may have a substituent.)

[0022] Examples of monovalent organic groups that may have substituents represented by R, R', R'', and R''' in formula (I) include hydrocarbon groups that may contain one or more atoms selected from the group consisting of elements from groups 15 to 17.

[0023] Examples of group 15 to 17 elements that may be contained in the above hydrocarbon group include nitrogen, oxygen, sulfur, phosphorus, selenium, fluorine, chlorine, and bromine atoms. Of these, nitrogen, oxygen, sulfur, and phosphorus atoms are preferred.

[0024] The hydrocarbon group described above may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group may be linear or cyclic. It may also have a carbon-carbon unsaturated bond. Of these, the hydrocarbon group is preferably an aliphatic hydrocarbon group, more preferably a linear aliphatic hydrocarbon group, and even more preferably a linear aliphatic hydrocarbon group. In this specification, the term "aromatic hydrocarbon group" includes an aromatic heterocyclic group. Furthermore, the aromatic hydrocarbon group may be a monocyclic ring or a ring formed by the bonding or fusion of multiple rings, and these rings may have substituents. Furthermore, the phrase "may contain one or more atoms selected from the group consisting of elements of groups 15 to 17" means that the substituents may include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, astatine atoms, primary amino groups, hydroxyl groups, carboxyl groups, carboxylate groups, thiol groups, acetyl groups, carboxymethyl groups, nitrogen-containing aromatic ring groups, etc. In addition, it means that the carbon skeleton may contain secondary amino groups, tertiary amino groups, ether bonds, carbonyl bonds, thioether bonds, and other linking groups containing nitrogen or sulfur atoms. Primary amino groups, secondary amino groups, and tertiary amino groups may be protonated. Of these, the substituents are preferably carboxylate groups, and more preferably carboxylate groups and nitrogen-containing aromatic ring groups. Note that the embodiment of containing a secondary amino group in the carbon skeleton of a hydrocarbon group does not refer to a polymer containing repeating units having amino groups in the polymer main chain.

[0025] The number of carbon atoms in the hydrocarbon group described above (including substituents, if any) is not particularly limited, and a suitable number of carbon atoms can be selected to fall within the molecular weight range described later. From the viewpoint of promoting biodegradability, availability, and workability, the number of carbon atoms in the hydrocarbon group described above (including substituents, if any) is preferably 1 to 40, and more preferably 1 to 20.

[0026] It is preferable that at least one of R, R', R'', and R''' in formula (I) is a hydrocarbon group which may have substituents. Furthermore, it is preferable that at least one of R, R', R'', and R''' is a hydrogen atom, more preferably two are hydrogen atoms, and even more preferably three are hydrogen atoms.

[0027] A preferred embodiment is a hydrocarbon group having 1 to 20 carbon atoms, where three atoms R, R', R'', and R'''' are hydrogen atoms, and one atom may have a substituent. The hydrocarbon group is preferably an aliphatic hydrocarbon group, more preferably a linear aliphatic hydrocarbon group, and even more preferably a linear aliphatic hydrocarbon group. Examples of substituents that the hydrocarbon group may have include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, astatine atoms, primary amino groups, hydroxyl groups, carboxyl groups, carboxylate groups, thiol groups, acetyl groups, carboxymethyl groups, nitrogen-containing aromatic ring groups, and the like. The hydrocarbon group preferably contains a carboxylate group as a substituent, and more preferably contains a carboxylate group and a nitrogen-containing aromatic ring group.

[0028] The molecular weight of the above ionic nitrogen compound is less than 10,000. From the viewpoint of promoting biodegradability, the molecular weight of the ionic nitrogen compound is preferably 5,000 or less, more preferably 1,000 or less, even more preferably 500 or less, and particularly preferably 400 or less. Furthermore, the lower limit of the molecular weight of the above ionic nitrogen compound is not particularly limited, but is usually 18 or more, preferably 50 or more, more preferably 90 or more, even more preferably 100 or more, and particularly preferably 150 or more.

[0029] The mass ratio of nitrogen to carbon in the above ionic nitrogen compound is preferably 5 or less, more preferably 2.5 or less, even more preferably 1.2 or less, even more preferably 1.0 or less, particularly preferably 0.8 or less, and most preferably 0.7 or less. The lower limit of the above mass ratio is preferably 0.01 or more, more preferably 0.05 or more, even more preferably 0.10 or more, and even more preferably 0.13 or more.

[0030] The ratio of nitrogen atoms to carbon atoms in the above ionic nitrogen compound is preferably 5 or less, more preferably 2.5 or less, even more preferably 1.2 or less, even more preferably 1.0 or less, particularly preferably 0.8 or less, and most preferably 0.7 or less. The lower limit of the above ratio is preferably 0.01 or more, more preferably 0.05 or more, even more preferably 0.10 or more, and even more preferably 0.13 or more.

[0031] The specific complex may consist of only one or two or more of the above-mentioned ionic nitrogen compounds. If the above ionic nitrogen compound contains secondary and tertiary amines, it is preferable that their content be low. When primary, secondary, and tertiary amines are present in the above ionic nitrogen compound, the ratio of primary amine to the total of secondary and tertiary amines is preferably 0.1 or more, more preferably 0.4 or more, and even more preferably 1.0 or more. There is no particular upper limit, but it is preferably 5 or less, and more preferably 2.5 or less. The ratio of amines refers to the ratio of nitrogen atoms in the primary to tertiary amino groups contained in one molecule. For example, if the ionic nitrogen compound is a compound that has one primary amine and a total of two secondary and tertiary amines in one molecule, the ratio of primary amine to the total of secondary and tertiary amines is 0.5.

[0032] The nitrogen atom concentration in the above ionic nitrogen compound is preferably 6% by mass or more, more preferably 7% by mass or more, and even more preferably 10% by mass or more, in order to easily exhibit a biodegradation-promoting effect. The upper limit is preferably 60% by mass or less, more preferably 50% by mass or less, even more preferably 40% by mass or less, and particularly preferably 35% by mass or less.

[0033] The above-mentioned ionic nitrogen compound may be anionic or cationic, but it is preferable that it be cationic at neutral. That is, the isoelectric point (pI) of the ionic nitrogen compound is preferably higher than the pH of the aqueous solution during the adsorption treatment on the support. The isoelectric point of the above ionic nitrogen compound is preferably 7.0 or higher, more preferably 7.5 or higher, even more preferably 8.0 or higher, and most preferably 8.5 or higher. The upper limit of the isoelectric point is preferably 13.0 or lower, more preferably 12.0 or lower, even more preferably 11.0 or lower, and most preferably 10.0 or lower.

[0034] The above-mentioned ionic nitrogen compound is preferably a compound that does not easily inhibit the growth of microorganisms. Furthermore, from a safety standpoint, it is preferable that it is not a hazardous material or insecticide.

[0035] Specific examples of the above-mentioned ionic nitrogen compounds include amino acids, monoalkylamines, alkylenediamines, and polyamines, with amino acids being preferred. More specific examples include amino acids such as histidine, arginine, and lysine; monoalkylamines such as ethylamine, propylamine, butylamine, pentylamine, hexylamine, and isobutylamine; alkylenediamines such as ethylenediamine, trimethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, putrescine, and octamethylenediamine; alkylenediamines having an NH group in the alkylene skeleton, such as norspermidine, spermine, and spermidine; and polyamines such as putrescine. Two or more of these may be used in combination. These compounds have a high nitrogen concentration in their molecules, are low molecular weight, and are quickly taken up by microorganisms and used as nutrients, making them useful for decomposing resins. Among these, histidine, arginine, lysine, tetramethylenediamine (putrescin), pentamethylenediamine (cadaverine), hexamethylenediamine, heptamethylenediamine, spermine, spermidine, and norspermidine are more preferred, histidine, arginine, lysine, and hexamethylenediamine are particularly preferred, and histidine is the most preferred.

[0036] The content of ionic nitrogen compounds in the resin composition is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, and most preferably 1% by mass or more. The upper limit of the content of ionic nitrogen compounds is preferably 50% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, particularly preferably 10% by mass or less, and most preferably 5% by mass or less. Setting the content above the lower limit tends to result in a significant biodegradation-promoting effect, while setting it below the upper limit tends to maintain good mechanical properties.

[0037] <<Carrier>> The support material used in the above-mentioned specific composite is not particularly limited as long as it can adsorb and support the above-mentioned ionic nitrogen compound by non-covalent bonds. Examples include crosslinkable synthetic polymers such as polyvinyl alcohol polymers, styrene-divinylbenzene polymers, and (meth)acrylic polymers; natural organic polymers such as cellulose, Sepharose, agarose, chitosan, and chitin; and inorganic polymers such as acid clay, activated clay, bentonite, montmorillonite, silica, glass, ceramics, and clay minerals. The silica may be crystalline silica or amorphous silica. It is preferable to partially modify these support materials to facilitate the adsorption of ionic nitrogen compounds.

[0038] The support used in the above-mentioned specific composite preferably contains naturally derived materials. Furthermore, the support is preferably biodegradable. The support is preferably a natural inorganic polymer such as acid clay, activated clay, bentonite, montmorillonite, silica, or clay minerals, or a natural organic polymer such as cellulose. The support material is preferably composed of finer particles, as this affects the mechanical properties when mixed with the resin. The support preferably contains at least one selected from acid clay, activated clay, bentonite, montmorillonite, and silica, more preferably contains at least one selected from acid clay and activated clay, and most preferably contains acid clay.

[0039] The carrier is preferably a porous material. A porous material has a large surface area, which allows it to adsorb a large amount of ionic nitrogen compounds into its pores.

[0040] The support preferably has ionic functional groups. When the support has ionic functional groups, the ionic nitrogen compound is adsorbed onto the support by ionic bonding with the ionic functional groups of the support. The ionic functional group on the support may be a cationic or anionic functional group. Examples of cationic functional groups include ammonium groups, phosphonium groups, and diethylaminoethyl groups. Examples of anionic functional groups include carboxylate groups, sulfonate groups, and carboxymethyl groups. If the above-mentioned ionic nitrogen compound is a cationic compound, it is preferable that the ionic functional group on the support is an anionic functional group. If the above-mentioned ionic nitrogen compound is an anionic compound, it is preferable that the ionic functional group of the support is a cationic functional group.

[0041] A preferred embodiment of the above-mentioned specific complex is one in which the ionic nitrogen compound is a cationic compound, the support has anionic functional groups, and the ionic nitrogen compound is adsorbed onto the support by ionic bonding with the anionic functional groups of the support.

[0042] For the support to be anionic, when a mineral is used as the support, for example, it is preferable that the support contains a large amount of SiO2. The molar ratio of SiO2 / Al2O3 is preferably 5 or more, more preferably 6 or more, and even more preferably 7 or more. The upper limit of the above molar ratio is preferably 11 or less, more preferably 10 or less, and even more preferably 9 or less.

[0043] The particle size of the support is preferably 100 μm or less, more preferably 50 μm or less, even more preferably 30 μm or less, and most preferably 25 μm or less. There is no particular lower limit to the particle size of the support, but for ease of handling, it is preferably 0.1 μm or more, more preferably 1.0 μm or more, even more preferably 5.0 μm or more, particularly preferably 10.0 μm or more, and most preferably 15.0 μm or more. In this specification, the particle size of the support is a value obtained by sieving.

[0044] The content of the support in the resin composition is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, even more preferably 1.0% by mass or more, particularly preferably 3.0% by mass or more, and most preferably 4.0% by mass or more. The upper limit of the support content is preferably 30.0% by mass or less, more preferably 20.0% by mass or less, even more preferably 10.0% by mass or less, particularly preferably 7.5% by mass or less, and most preferably 6.0% by mass or less. Setting the content above the lower limit tends to significantly promote biodegradation, while setting it below the upper limit tends to maintain good mechanical properties.

[0045] <Resin> The resin composition according to this embodiment includes a resin. While there are no particular limitations on the resin, a biodegradable resin is preferred. Examples include polyvinyl alcohol (PVA), polyglycolic acid (PGA), polyester resin, and polyamide resin. The resin contained in the resin composition according to this embodiment may be used alone, or two or more resins may be used in any combination and ratio. The resin can be used individually, or a blend of two or more resins differing in constituent unit types, constituent unit ratios, manufacturing methods, physical properties, etc.

[0046] <<Polyester resin>> The resin composition according to this embodiment preferably contains a polyester resin, which has good moldability and mechanical properties and is easily hydrolyzed. A biodegradable polyester resin is preferred as the polyester resin. The degree of biodegradation of the resin and resin composition will be described later. The polyester resin contained in the resin composition according to this embodiment may be one type alone, or two or more types of polyester resins may be used in any combination and ratio. Preferred polyester resins include biodegradable polyester resins such as polylactic acid (PLA), polyhydroxyalkanoate (PHA), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), polycaprolactone (PCL), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), polybutylene succinate sebacate (PBSSe), polybutylene adipate terephthalate (PBAT), and polybutylene sebacate terephthalate (PBSeT). The polyester resin may be a single type, or two or more resins with different types and numbers of constituent units, ratios of constituent units, manufacturing methods, and physical properties may be used in combination. Other resins may also be used in combination. Preferred other resins include biodegradable resins such as polyvinyl alcohol, polyamide, and polyethylene glycol.

[0047] Polyester resins are described in detail below. Each repeating unit in a polyester resin is also called a compound unit for the compound from which the repeating unit originates. For example, a repeating unit derived from an aliphatic diol is called an "aliphatic diol unit," a repeating unit derived from an aliphatic dicarboxylic acid is called an "aliphatic dicarboxylic acid unit," and a repeating unit derived from an aromatic dicarboxylic acid is called an "aromatic dicarboxylic acid unit." Furthermore, the "main constituent unit" in a polyester resin is usually a constituent unit that is present in the polyester resin at a concentration of 80% by mass or more, and this also includes cases where no constituent units other than the main constituent unit are present.

[0048] The polyester resin contained in the resin composition according to this embodiment is preferably a polyester resin having diol units and dicarboxylic acid units.

[0049] The polyester resin may be an aliphatic polyester resin, an aromatic polyester resin, or an aliphatic-aromatic polyester resin. Aliphatic polyester resins or aliphatic-aromatic polyester resins are preferred in terms of high flexibility, and aliphatic polyester resins are more preferred from the viewpoint of biodegradability. In this specification, "aromatic" also includes heteroaromatic compounds. It is preferable for polyester resins to have two or more structural units, and more preferably two or more dicarboxylic acid units, because a decrease in the crystallinity of the polyester resin and an increase in amorphous regions are thought to accelerate biodegradation.

[0050] (Diol units) The diol units in the polyester resin may be aliphatic or aromatic. Furthermore, the polyester resin may contain only one type of diol unit, or two or more types of units in any combination and ratio, and may contain both aliphatic and aromatic diol units. In terms of biodegradability, it is preferable to include aliphatic diol units in the constituent units, and more preferably to have linear aliphatic diol units.

[0051] The diol unit is preferably the diol unit represented by formula (1). -OR 1 -O- (1) In formula (1), R 1 This represents an aliphatic hydrocarbon group with 2 to 20 carbon atoms.

[0052] R 1 The number of carbon atoms in the aliphatic hydrocarbon group represented by is preferably 4 or more from the viewpoint of moldability, mechanical strength, etc. The upper limit is preferably 16 or less, more preferably 13 or less, even more preferably 10 or less, and particularly preferably 6 or less. A particularly preferred aliphatic hydrocarbon group is an aliphatic hydrocarbon group with 4 carbon atoms. Examples of aliphatic diols that give the aliphatic diol unit represented by formula (1) are ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,4-cyclohexanedimethanol, with 1,4-butanediol, 1,3-propanediol, and ethylene glycol being more preferred, and 1,4-butanediol being particularly preferred.

[0053] The diol units contained in the polyester resin may have aromatic diol units. Specific examples of aromatic diol components that provide aromatic diol units include xylylene glycol, 4,4'-dihydroxybiphenyl, 2,2-bis(4'-hydroxyphenyl)propane, 2,2-bis(4'-β-hydroxyethoxyphenyl)propane, bis(4-hydroxyphenyl)sulfone, and bis(4-β-hydroxyethoxyphenyl)sulfonic acid. The aromatic diol component of the raw material that forms the aromatic diol unit may be a derivative of an aromatic diol compound. It may also be a compound having a structure in which multiple aliphatic diol compounds and / or aromatic diol compounds are dehydrated and condensed with each other. The diol units in the polyester resin preferably contain 30 mol% or more of the above-mentioned preferred diol units, and more preferably 50 mol% or more, relative to the total number of diol units. The upper limit is 100 mol%.

[0054] (Dicarboxylic acid unit) The dicarboxylic acid units in the polyester resin may be aliphatic or aromatic. Furthermore, the polyester resin may contain only one type of dicarboxylic acid unit, or two or more types of units in any combination and ratio, and may contain both aliphatic and aromatic dicarboxylic acid units. In terms of biodegradability, it is preferable to include aliphatic dicarboxylic acid units in the constituent units. The number of carbon atoms in a dicarboxylic acid unit is more preferably 2 or more, and even more preferably 4 or more, from the viewpoint of biodegradability, moldability, and mechanical strength. The upper limit is preferably 22 or less, more preferably 16 or less, even more preferably 13 or less, and most preferably 10 or less.

[0055] The dicarboxylic acid unit is preferably a dicarboxylic acid unit represented by formula (2). -OC-R 2 -CO- (2) In formula (2), R 2 The symbols represent a single bond, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, or an aromatic hydrocarbon group or heteroaromatic group having 4 to 8 carbon atoms.

[0056] R 2 The number of carbon atoms in the aliphatic hydrocarbon group represented by is preferably 2 or more, more preferably 4 or more. The upper limit is preferably 16 or less, more preferably 12 or less, and even more preferably 8 or less. When a polyester resin contains two or more types of aliphatic dicarboxylic acid units, a preferred combination of aliphatic hydrocarbon groups is one having two carbon atoms and another having four to ten carbon atoms.

[0057] The aliphatic dicarboxylic acid component that gives the aliphatic dicarboxylic acid unit represented by formula (2) is not particularly limited, but aliphatic dicarboxylic acids or derivatives thereof such as alkyl esters, in which the number of carbon atoms in the carboxylic acid unit containing the carboxyl group is within the above-mentioned preferred range, and aliphatic carboxylic acids or derivatives thereof such as alkyl esters having 4 to 10 carbon atoms are more preferred. Preferred aliphatic dicarbon units include, for example, oxalic acid units, malonic acid units, succinic acid units, glutaric acid units, adipic acid units, pimelic acid units, suberic acid units, azelaic acid units, sebacic acid units, brassic acid units, undecanediic acid units, and dodecanediic acid units. Of these, adipic acid units, azelaic acid units, succinic acid units, and sebacic acid units are preferred, succinic acid units and sebacic acid units are more preferred, and succinic acid units are particularly preferred.

[0058] In polyester resins, the proportion of the above-mentioned preferred dicarboxylic acid units in the total dicarboxylic acid units is preferably 5 mol% or more, more preferably 10 mol% or more, even more preferably 50 mol% or more, particularly preferably 64 mol% or more, and most preferably 68 mol% or more. The upper limit is 100 mol%. By setting the proportion of preferred dicarboxylic acids in the polyester resin within the above range, it is possible to obtain a biodegradable resin composition that has improved moldability as well as excellent heat resistance and biodegradability. Furthermore, when the polyester resin contains aliphatic dicarboxylic acid units, it is preferable that the aliphatic dicarboxylic acid units make up 30 mol% or more of the total dicarboxylic acid units, and more preferably 40 mol% or more. The upper limit is 100 mol%. Furthermore, if the polyester resin contains aromatic dicarboxylic acid units, the amount of aromatic dicarboxylic acid units is preferably 70 mol% or less, and more preferably 60 mol% or less, relative to the total amount of dicarboxylic acid units.

[0059] The polyester preferably contains two or more aliphatic dicarboxylic acid components, and more preferably contains two or more of the preferred aliphatic dicarboxylic acid components described above. In this case, the combination of aliphatic dicarboxylic acid units is preferably a combination of a four-carbon aliphatic dicarboxylic acid unit and a six- to thirteen-carbon aliphatic dicarboxylic acid unit, and more preferably a combination of a four-carbon aliphatic dicarboxylic acid unit and a six- to thirteen-carbon aliphatic dicarboxylic acid unit. Specifically, the combination of aliphatic dicarboxylic acid units preferably includes at least one of succinic acid units, adipic acid units, azelaic acid units, sebacic acid units, and brassic acid units, and more preferably a combination of two or more dicarboxylic acid units from among these.

[0060] Preferred dicarboxylic acid units to be combined with succinic acid units include pimelic acid units, suberic acid units, azelaic acid units, adipic acid units, sebacic acid units, undecanediic acid units, brassic acid units, or dodecanediic acid units. Combinations with adipic acid units or sebacic acid units are more preferred, and combinations with sebacic acid units are even more preferred. Specifically, the following polyester resins are preferred. Preferred polyester resins having succinic acid units include polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), polybutylene succinate sebacate (PBSSe), and polybutylene succinate azelate (PBSAz), with polyester resins having two or more dicarboxylic acid units, such as polybutylene succinate adipate (PBSA), polybutylene succinate sebacate (PBSSe), polybutylene succinate azelate (PBSAz), and polybutylene succinate brassilate (PBSBr), being more preferred. Preferred polyester resins having sebaciic acid units include polybutylene succinate sebacate (PBSSe), polybutylene sebacate terephthalate (PBSeT), and polybutylene sebacate furanoate (PBSeF). Preferred polyester resins containing azelaic acid units include polybutylene succinate azelate (PBSAz) and polybutylene azelate terephthalate (PBAzT). Preferred polyester resins containing adipic acid units include polybutylene succinate adipate (PBSA) and polybutylene adipate terephthalate (PBAT). Preferred polyester resins containing brassic acid units include polybutylene succinate brassilate (PBSBr) and polybutylene brassilate terephthalate (PBBrT).

[0061] The dicarboxylic acid units combined with succinic acid units are preferably present in an amount of 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more, relative to the total dicarboxylic acid units. On the other hand, it is more preferably 50 mol% or less, more preferably 45 mol% or less, and even more preferably 40 mol% or less. By copolymerizing aliphatic dicarboxylic acid units other than succinic acid units within the above range, the crystallinity of the polyester resin can be reduced, and the biodegradation rate can be increased.

[0062] The number of carbon atoms in the aromatic dicarboxylic acid unit represented by formula (2) is usually 4 or more and 8 or less, preferably 6 or more. Specifically, examples include 1,2-phenylene group, 1,3-phenylene group, 1,4-phenylene group, 2,5-franziyl group, etc.

[0063] The aromatic dicarboxylic acid component that gives the aromatic dicarboxylic acid unit represented by formula (2) is not particularly limited, but is usually an aromatic dicarboxylic acid or derivative thereof with the preferred number of carbon atoms as described above. Specifically, examples include phthalic acid, isophthalic acid, terephthalic acid, 2,5-franzicarboxylic acid, etc. or derivatives thereof, among which terephthalic acid and 2,5-franzicarboxylic acid or derivatives thereof are preferred, and 2,5-franzicarboxylic acid or derivatives thereof are even more preferred.

[0064] Derivatives of aromatic dicarboxylic acids include lower alkyl esters and acid anhydrides of aromatic dicarboxylic acids, each having 1 to 4 carbon atoms. Specific examples of derivatives of aromatic dicarboxylic acids include lower alkyl esters such as methyl esters, ethyl esters, propyl esters, and butyl esters of the aforementioned aromatic dicarboxylic acids; and cyclic acid anhydrides of aromatic dicarboxylic acids. Among these, dimethyl terephthalate is preferred. The polyester resin having dicarboxylic acid units may be a polyester resin with different amounts of dicarboxylic acid units. For example, it is possible to blend a polyester resin containing only the preferred dicarboxylic acid units described above with a polyester resin containing other dicarboxylic acid units to adjust the proportion of preferred dicarboxylic acid units in the polyester resin to within the above range.

[0065] (Oxycarboxylic acid unit) The polyester resin may also be a resin containing oxycarboxylic acid units. The oxycarboxylic acid units contained in the polyester resin are preferably aliphatic oxycarboxylic acid units represented by formula (3). -OR 3 -CO- (3) In formula (3), R 3represents an aliphatic hydrocarbon group having 1 to 20 carbon atoms.

[0066] R 3 The number of carbon atoms in the aliphatic hydrocarbon group represented by 3 is preferably 16 or less, more preferably 12 or less, and still more preferably 8 or less.

[0067] The aliphatic oxycarboxylic acid unit represented by formula (3) is not particularly limited, and examples thereof include hydroxy acid units such as lactic acid unit, glycolic acid unit, 3-hydroxybutyric acid unit, 2-hydroxy-n-butyric acid unit, 2-hydroxycaproic acid unit, 6-hydroxycaproic acid unit, 2-hydroxy-3,3-dimethylbutyric acid unit, 2-hydroxy-3-methylbutyric acid unit, 2-hydroxyisocaproic acid unit, 3-hydroxypropionic acid unit, 4-hydroxybutyric acid unit, 5-hydroxyvaleric acid unit, 6-hydroxycaproic acid unit, etc. These aliphatic oxycarboxylic acid units may be used as raw materials in the form of derivatives such as their lower alkyl esters or intramolecular esters. When optical isomers exist in these units, either the D-form or the L-form may be used. Among these, preferred are glycolic acid unit and 3-hydroxybutyric acid unit.

[0068] When the polyester resin contains these aliphatic oxycarboxylic acid units, the content thereof is preferably 20 mol% or less, more preferably 10 mol% or less, and still more preferably 5 mol% or less based on all the constituent units constituting the polyester resin from the viewpoint of moldability. Note that the polyester resin may not contain aliphatic oxycarboxylic acid units.

[0069] The oxycarboxylic acid unit contained in the polyester resin may contain an aromatic oxycarboxylic acid unit. Specific examples of aromatic oxycarboxylic acid units include, for example, p-hydroxybenzoic acid units and p-β-hydroxyethoxybenzoic acid units. The raw material that gives the aromatic oxycarboxylic acid units may be a derivative of an aromatic oxycarboxylic acid compound. Alternatively, it may be a compound (oligomer) having a structure in which multiple aromatic oxycarboxylic acid compounds and / or aromatic oxycarboxylic acid compounds are dehydrated and condensed with each other. In other words, an oligomer may be used as the raw material.

[0070] If optical isomers exist for the aromatic compound component that yields these aromatic compound units, any of the D-isomer, L-isomer, or racemic mixture may be used. Furthermore, the aromatic compound component is not limited to the above examples, as long as it can yield aromatic compound units.

[0071] (Units with 3 or more functions) The polyester resin may be a resin whose melt viscosity has been increased by copolymerizing a trifunctional or higher aliphatic polyhydric alcohol with a trifunctional or higher aliphatic polyhydric carboxylic acid or its acid anhydride, or a trifunctional or higher aliphatic polyoxycarboxylic acid component. When using these copolymer components, one type may be used alone, or two or more types may be used in any combination and ratio.

[0072] Examples of trifunctional aliphatic polyhydric alcohols include trimethylolpropane and glycerin. Examples of tetrafunctional aliphatic polyhydric alcohols include pentaerythritol. Specific examples of trifunctional aliphatic polycarboxylic acids or their acid anhydrides include propanetricarboxylic acid or its acid anhydride. Specific examples of tetrafunctional polycarboxylic acids or their acid anhydrides include cyclopentanetetracarboxylic acid or its acid anhydride, etc.

[0073] Furthermore, trifunctional aliphatic oxycarboxylic acids can be broadly classified into two types: (i) those having two carboxyl groups and one hydroxyl group in the same molecule, and (ii) those having one carboxyl group and two hydroxyl groups. While both types can be used, from the viewpoint of moldability, mechanical strength, and the appearance of the molded product, the type having (i) two carboxyl groups and one hydroxyl group in the same molecule, such as malic acid, is preferred, and malic acid is more preferred. Furthermore, tetrafunctional aliphatic oxycarboxylic acid components can be broadly classified into three types: (i) those sharing three carboxyl groups and one hydroxyl group in the same molecule, (ii) those sharing two carboxyl groups and two hydroxyl groups in the same molecule, and (iii) those sharing three hydroxyl groups and one carboxyl group in the same molecule. Any type can be used, but those having multiple carboxyl groups are preferred, and citric acid and tartaric acid are more preferred. These may be used individually or in any combination and ratio of two or more types.

[0074] When the polyester resin contains structural units derived from the above-mentioned three or more functional components, the content of these units is preferably 0.01 mol% or more, and more preferably 5 mol% or less, and more preferably 2.5 mol% or less, as the amount contained in the total structural units constituting the polyester resin. Furthermore, the polyester resin does not need to contain constituent units derived from the three or more functional components mentioned above.

[0075] (Types of polyester resin) The polyester resin contained in the resin composition according to this embodiment is preferably an aliphatic polyester resin (hereinafter sometimes referred to as "aliphatic polyester resin (A)") which contains aliphatic diol units and aliphatic dicarboxylic acid units as the main constituent units, an aliphatic-aromatic polyester resin (B) which is a resin in which at least a portion of the repeating units of aliphatic polyester resin (A) are replaced with aromatic compound units, and an aromatic polyester resin (polyarylate) (C) which is a resin in which the repeating units of aliphatic polyester resin (A) are replaced with aromatic compound units. Aliphatic polyester resin (A) is more preferred in terms of its high biodegradability.

[0076] (Aliphatic polyester resin (A)) The aliphatic polyester resin (A) consists of aliphatic diol units represented by the above formula (1) and R 2 Aliphatic polyester resin containing an aliphatic dicarboxylic acid unit represented by the above formula (2), in which is an aliphatic hydrocarbon group; and an aliphatic diol unit represented by the above formula (1) and R 2 An aliphatic polyester resin containing an aliphatic dicarboxylic acid unit represented by the above formula (2), in which is an aliphatic hydrocarbon group, and an aliphatic oxycarboxylic acid unit represented by the above formula (3) is preferred. Note that the aliphatic diol unit represented by formula (1), R 2 The aliphatic dicarboxylic acid unit represented by formula (2) and the aliphatic oxycarboxylic acid unit represented by formula (3), where is an aliphatic hydrocarbon group, are as described above. Furthermore, the preferred aliphatic polyester resin as the aliphatic polyester (A), and the case in which the aliphatic polyester resin (A) is copolymerized with a trifunctional or higher aliphatic polyhydric alcohol and a trifunctional or higher aliphatic polyhydric carboxylic acid or its acid anhydride or a trifunctional or higher aliphatic polyhydric oxycarboxylic acid component are also as described above.

[0077] As the aliphatic polyester resin (A), polybutylene succinate-based resins such as polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), polybutylene succinate sebacate (PBSSe), polybutylene succinate azelate (PBSAz), and polybutylene brasilate terephthalate (PBSBr) are particularly preferred due to their high biodegradability.

[0078] (Aliphatic-aromatic polyester resin (B)) Aliphatic-aromatic polyester resin (B) is a resin in which at least some of the repeating units of the aliphatic polyester resin (A) described above are replaced with aromatic compound units. Aliphatic-aromatic polyester resin (B) is an aliphatic diol unit represented by formula (1) described above and R 2 Aliphatic-aromatic polyester resin containing an aromatic dicarboxylic acid unit represented by the above formula (2), in which is an aromatic group; an aliphatic diol unit represented by formula (1), R 2 Aliphatic-aromatic polyester resins are preferred that contain aromatic dicarboxylic acid units represented by formula (2) and aliphatic oxycarboxylic acid units represented by formula (3), where the aromatic hydrocarbon group is the aromatic hydrocarbon group.

[0079] Note that the aliphatic diol unit represented by formula (1), R 2 The aromatic dicarboxylic acid unit represented by formula (2) and the aliphatic oxycarboxylic acid unit represented by formula (3), where is an aromatic hydrocarbon group, are as described above. Furthermore, the preferred aliphatic polyester as the aliphatic-aromatic polyester (B) is also as described above, including the case in which the aliphatic-aromatic polyester resin (B) is copolymerized with a trifunctional or higher aliphatic polyhydric alcohol and a trifunctional or higher aliphatic polyhydric carboxylic acid or its acid anhydride or a trifunctional or higher aliphatic polyhydric oxycarboxylic acid component.

[0080] Aliphatic-aromatic polyester resin (B) may contain aromatic diol units. In other words, the aliphatic-aromatic polyester resin (B) may be a polyester resin having aromatic diol units and aliphatic dicarboxylic acid units; aromatic diol units and aliphatic dicarboxylic acid units and aromatic dicarboxylic acid units; aliphatic diol units and aromatic diol units and aromatic dicarboxylic acid units; aliphatic diol units and aromatic diol units and aliphatic dicarboxylic acid units and aromatic dicarboxylic acid units. Specific examples of aromatic diol components are as described above.

[0081] Aliphatic-aromatic polyester resin (B) may contain aromatic oxycarboxylic acid units. Specific examples of aromatic oxycarboxylic acid components that provide aromatic oxycarboxylic acid units are as described above.

[0082] The aliphatic-aromatic polyester resin (B) preferably has aromatic dicarboxylic acid units as aromatic units, and in this case, the content of aromatic dicarboxylic acid units is preferably 10 mol% or more and 80 mol% or less, based on the total amount of aliphatic dicarboxylic acid units and aromatic dicarboxylic acid units (100 mol%).

[0083] It is preferable to use terephthalic acid units or 2,5-franzicarboxylic acid units as aromatic dicarboxylic acid units. Specifically, as the aliphatic-aromatic polyester resin (B), polybutylene terephthalate resins such as polybutylene adipate terephthalate (PBAT), polybutylene succinate terephthalate (PBST), polybutylene sebacate terephthalate (PBSeT), polybutylene azelate terephthalate (PBAzT), and polybutylene brushlate terephthalate (PBBrT) are preferred, as are polyflange carboxylate resins such as polybutylene adipate furanoate (PBAF), polybutylene succinate furanoate (PBSF), polybutylene sebacate furanoate (PBSeF), polybutylene succinate sebacate furanoate (PBSSeF), polybutylene adipate sebacate furanoate (PBASeF), and polybutylene azelate furanoate (PBAzF) are preferred.

[0084] As the aliphatic-aromatic polyester resin (B), resins having succinic acid units, adipic acid units, and sebacic acid units as dicarboxylic acid units are preferred. Therefore, as the aliphatic-aromatic polyester resin (B), polybutylene succinate resins such as PBST, PBSF, and PBSSeF; polybutylene adivate resins such as PBAT, PBAF, and PBASeF; and polybutylene sebacate resins such as PBSeT and PBSeF are preferred; PBAzT (polybutylene azelate terephthalate) and PBAzF (polybutylene azelate furanoate) are preferred, and polybutylene succinate-aromatic dicarboxylic acid resins such as PBST, PBSF, and PBSSeF are even more preferred.

[0085] (Aromatic polyester resin (C)) Aromatic polyester resin (polyarylate) (C) is a resin in which the repeating units of the aliphatic polyester resin (A) described above are replaced with aromatic compound units. The aromatic polyester resin (C) may contain aromatic diol units and R 2 Aromatic polyester resin containing aromatic dicarboxylic acid units represented by the above formula (2), where is an aromatic hydrocarbon group; aliphatic-aromatic polyester resin (B) may contain aromatic diol units, R 2 Preferred are aromatic polyester resins, etc., that include aromatic dicarboxylic acid units represented by the above formula (2), which are aromatic hydrocarbon groups, and aromatic oxycarboxylic acid units that may be included in the aliphatic-aromatic polyester resin (B).

[0086] The units and other components contained in aromatic polyester resin (C) are as described above.

[0087] (Method of manufacturing polyester resin) The method for producing polyester resin can employ known methods for producing polyester resin. Furthermore, the polycondensation reaction in this process can be carried out under conventionally adopted and appropriate conditions, and is not particularly limited. The method for producing polyester resin containing diol units and dicarboxylic acid units is described in detail below as an example.

[0088] Polyester resins containing diol units and dicarboxylic acid units are typically subjected to a method in which the degree of polymerization is further increased by carrying out an esterification reaction followed by a reduced pressure operation.

[0089] When manufacturing polyester resins, if a diol component that forms diol units is reacted with a dicarboxylic acid component that forms dicarboxylic acid units, the amounts of the diol component and the dicarboxylic acid component used are adjusted so that the resulting polyester resin has the desired composition. Normally, the diol component and the dicarboxylic acid component react in substantially equimolar amounts, but since the diol component distills off during the esterification reaction, it is usually used in an excess of 1 mol% to 20 mol% compared to the dicarboxylic acid component.

[0090] When copolymerizing polyester resin with components such as oxycarboxylic acid units and polyfunctional component units, the oxycarboxylic acid units and polyfunctional component units can be reacted using the corresponding compounds (monomers or oligomers) so that they achieve the desired composition. There are no restrictions on the timing or method of introducing these components into the reaction system; it is arbitrary as long as the polyester resin can be produced.

[0091] For example, when copolymerizing a polyester resin with an oxycarboxylic acid, the timing of introducing the oxycarboxylic acid component is not particularly limited as long as it is before the polycondensation reaction between the diol component and the dicarboxylic acid component. Methods include mixing the catalyst after dissolving it in the oxycarboxylic acid solution beforehand, or introducing the catalyst into the reaction system and mixing it at the same time as the raw materials are being prepared.

[0092] The timing of introducing the compound that forms the polyfunctional component unit can be either simultaneously with the other monomers or oligomers in the early stages of polymerization, or after the transesterification reaction and before starting the reduced pressure. However, introducing it simultaneously with the other monomers or oligomers is preferable in terms of simplifying the process.

[0093] Polyester resins are typically manufactured in the presence of a catalyst. Any catalyst that can be used in the production of known polyester resins can be arbitrarily selected, as long as it does not significantly impair the effects of the present invention. Examples of suitable catalysts include metal compounds such as germanium, titanium, zirconium, hafnium, antimony, tin, magnesium, calcium, and zinc. Among these, germanium compounds and titanium compounds are particularly preferred.

[0094] Examples of germanium compounds that can be used as catalysts include organic germanium compounds such as tetraalkoxygermanium, and inorganic germanium compounds such as germanium oxide and germanium chloride. Among these, germanium oxide, tetraethoxygermanium, or tetrabutoxygermanium are preferred due to their price and availability, and germanium oxide is particularly preferred.

[0095] Examples of titanium compounds that can be used as catalysts include organotitanium compounds such as tetrapropyl titanate, tetrabutyl titanate, and tetraphenyl titanate, which are tetraalkoxy titanium compounds. Among these, tetrapropyl titanate and tetrabutyl titanate are preferred due to their price and availability.

[0096] Furthermore, the use of other catalysts is not prohibited as long as it does not impair the objective of the present invention. Note that one type of catalyst may be used alone, or two or more types may be used in any combination and ratio.

[0097] 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. By keeping the amount of catalyst within the above range, sufficient catalytic effect can be obtained while keeping manufacturing costs down, and discoloration or a decrease in hydrolysis resistance of the resulting polymer can be suppressed.

[0098] The timing of catalyst introduction is not particularly limited as long as it is before the polycondensation reaction; it may be introduced when the raw materials are being charged, or when the reduced pressure is started. When introducing aliphatic oxycarboxylic acid units, it is preferable to introduce them simultaneously with monomers or oligomers that form aliphatic oxycarboxylic acid units, such as lactic acid and glycolic acid, when the raw materials are being charged, or to dissolve the catalyst in an aqueous solution of aliphatic oxycarboxylic acid and introduce it. In particular, the method of dissolving the catalyst in an aqueous solution of aliphatic oxycarboxylic acid is preferred because it increases the polymerization rate.

[0099] The reaction conditions, such as temperature, polymerization time, and pressure, during the esterification and / or transesterification reaction between the dicarboxylic acid component and the diol component are arbitrary as long as they do not significantly impair the effects of the present invention. However, the reaction temperature for the esterification and / or transesterification reaction between the dicarboxylic acid component and the diol component is usually 150°C or higher, preferably 180°C or higher, and on the other hand, usually 260°C or lower, preferably 250°C or lower. The reaction atmosphere is usually an inert atmosphere such as nitrogen or argon. The reaction pressure is usually atmospheric pressure to 10 kPa, with atmospheric pressure being preferred. The reaction time is usually 1 hour or more, and on the other hand, usually 10 hours or less, preferably 6 hours or less, more preferably 4 hours or less. By setting the reaction conditions within the above range, gelation due to the excessive formation of unsaturated bonds can be suppressed, and the degree of polymerization can be controlled.

[0100] Furthermore, the pressure in the esterification reaction and / or the polycondensation reaction after the transesterification reaction between the dicarboxylic acid component and the diol component is typically 0.01 × 10⁻⁶. 3 Pa or higher, preferably 0.03 × 10⁻⁶3 It is above Pa, and on the other hand, it is usually 1.4 × 10 3 Pa or less, preferably 0.4 × 10 3 It is desirable to carry out the reaction under a vacuum of Pa or less. The reaction temperature is usually 150°C or higher, preferably 180°C or higher, and on the other hand, usually 260°C or lower, preferably 250°C or lower. The reaction time is usually 2 hours or more, and on the other hand, usually 15 hours or less, preferably 10 hours or less. By keeping the reaction conditions within the above range, gelation due to the excessive formation of unsaturated bonds can be suppressed, and the degree of polymerization can be controlled.

[0101] When manufacturing polyester resin, chain extenders such as carbonate compounds and diisocyanate compounds may be used. In this case, the amount of chain extender is usually 10 mol% or less, preferably 5 mol% or less, and more preferably 3 mol% or less, as a ratio of carbonate bonds or urethane bonds to the total constituent units of the polyester resin. From the viewpoint of the biodegradability of the biodegradable resin composition according to this embodiment, the amount of carbonate bonds is preferably less than 1 mol%, more preferably 0.5 mol% or less, and even more preferably 0.1 mol% or less, relative to the total constituent units of the polyester resin. The amount of urethane bonds is preferably 0.5 mol% or less, more preferably 0.3 mol% or less, even more preferably 0.12 mol% or less, and particularly preferably 0.05 mol% or less. Converting this amount to mass% relative to the polyester resin composition, it is preferably 0.9 mass% or less, more preferably 0.5 mass% or less, even more preferably 0.2 mass% or less, and particularly preferably 0.1 mass% or less. In particular, by keeping the amount of urethane bonding within the above range, smoke and odor caused by urethane bonding decomposition are suppressed during the film formation process, and film breakage due to foaming in the molten film is suppressed, thereby ensuring molding stability. The amount of carbonate bonding or urethane bonding in the polyester resin is 1 H-NMR and 13 It can be calculated from measurement results using NMR (nuclear magnetic resonance spectroscopy) such as 13C-NMR.

[0102] Examples of carbonate compounds used as chain extenders include diphenyl carbonate, ditrile carbonate, bis(chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, ethylene carbonate, diamyl carbonate, and dicyclohexyl carbonate. In addition, carbonate compounds derived from hydroxy compounds such as phenols and alcohols can also be used.

[0103] Examples of diisocyanate compounds include 2,4-tolylene diisocyanate, a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, tetramethylxylylene diisocyanate, 2,4,6-triisopropylphenyl diisocyanate, 4,4'-diphenylmethane diisocyanate, tolidine diisocyanate, and other known diisocyanates.

[0104] In addition, other chain extenders such as dioxazoline and silicate esters may be used. Examples of silica esters include tetramethoxysilane, dimethoxydiphenylsilane, dimethoxydimethylsilane, and diphenyldihydroxysilane.

[0105] High molecular weight polyester resins using these chain extenders (coupling agents) can also be manufactured using conventionally known techniques. Typically, the chain extender is added to the reaction system in a uniform molten state without a solvent after the polycondensation is complete, and reacted with the polyester obtained by polycondensation.

[0106] More specifically, a polyester resin with a higher molecular weight can be obtained by reacting a chain extender with a polyester resin having substantially hydroxyl end groups, which is obtained by catalytic reaction of a diol component and a dicarboxylic acid component. Prepolymers with a weight-average molecular weight of 20,000 or more can be used to produce high molecular weight polyester resins without gel formation during the reaction, even under harsh conditions such as a molten state, as they are not affected by residual catalyst, by the use of a small amount of chain extender. Here, the weight-average molecular weight (Mw) of the polyester resin is determined as a converted value for monodisperse polystyrene from the measurement value obtained by gel permeation chromatography (GPC) using chloroform as the solvent at a measurement temperature of 40°C.

[0107] Therefore, for example, when the weight-average molecular weight of the polyester resin is further increased using the above-mentioned diisocyanate compound as a chain extender, the weight-average molecular weight of the prepolymer is preferably 20,000 or more, and more preferably 40,000 or more. A higher weight-average molecular weight means that a smaller amount of diisocyanate compound is needed to increase the molecular weight, thus preventing a decrease in heat resistance. In this way, a polyester resin having urethane bonds having a linear structure linked via urethane bonds derived from the diisocyanate compound is produced.

[0108] The pressure during chain extension is preferably 0.01 MPa or higher, more preferably 0.05 MPa or higher, and even more preferably 0.07 MPa or higher. On the other hand, the pressure during chain extension is preferably 1 MPa or lower, more preferably 0.5 MPa or lower, and even more preferably 0.3 MPa or lower. And, most preferably, the pressure during chain extension is atmospheric pressure.

[0109] The reaction temperature during chain extension is preferably 100°C or higher, more preferably 150°C or higher, even more preferably 190°C or higher, and particularly preferably 200°C or higher. On the other hand, the reaction temperature during chain extension is preferably 250°C or lower, more preferably 240°C or lower, and even more preferably 230°C or lower. By keeping the reaction temperature within the above range, the reaction solution is maintained at an appropriate viscosity, enabling a uniform reaction, allowing the reaction solution to be sufficiently stirred without requiring high stirring power, and suppressing the simultaneous occurrence of gelation or decomposition of the polyester resin.

[0110] The chain extension reaction time is preferably 0.1 minutes or more, more preferably 1 minute or more, and even more preferably 5 minutes or more. On the other hand, the chain extension reaction time is preferably 5 hours or less, more preferably 1 hour or less, even more preferably 30 minutes or less, and particularly preferably 15 minutes or less. By keeping the chain extension time within the above range, the chain can be extended to the desired molecular weight, and the simultaneous occurrence of gelation or decomposition of the polyester resin can be suppressed.

[0111] (Aliphatic oxycarboxylic acid resin (D)) Aliphatic oxycarboxylic acid resins can also be used as polyester resins. Aliphatic oxycarboxylic acid resin (D) is a polyester resin whose main constituent unit is aliphatic oxycarboxylic acid unit. Examples of aliphatic oxycarboxylic acid resin (D) include aliphatic oxycarboxylic acid resins containing aliphatic oxycarboxylic acid units represented by the above formula (3).

[0112] In the aliphatic oxycarboxylic acid resin (D), the aliphatic oxycarboxylic acid unit and the component that provides the unit are defined in the same way as the aliphatic oxycarboxylic acid unit and aliphatic oxycarboxylic acid component in the aliphatic polyester resin (A) described above, and the preferred embodiment is also the same.

[0113] The aliphatic oxycarboxylic acid resin (D) is preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) or polycaprolactone (PCL), with polycaprolactone being more preferred.

[0114] Furthermore, within limits that do not affect biodegradability, urethane bonds, amide bonds, carbonate bonds, ether bonds, etc., may be introduced into the aliphatic oxycarboxylic acid resin (D).

[0115] The method for producing the aliphatic oxycarboxylic acid resin (D) is not particularly limited and can be produced by known methods such as direct polymerization of oxycarboxylic acids or ring-opening polymerization of cyclic compounds.

[0116] As the aliphatic oxycarboxylic acid resin (D), polyhydroxyalkanoate (E), as described below, is preferred.

[0117] (Polyhydroxyalkanoate (E)) Polyhydroxyalkanoate (E) is an aliphatic polyester containing repeating units represented by the formula:[-CHR-CH2-CO-O-] (wherein R is an alkyl group having 1 to 15 carbon atoms), and is a copolymer containing 3-hydroxybutyrate units and 3-hydroxyhexanoate units as its main constituent units.

[0118] From the viewpoint of moldability and thermal stability, polyhydroxyalkanoate (E) preferably contains 80 mol% or more of 3-hydroxybutyrate units as a constituent component, and more preferably 85 mol% or more. Furthermore, polyhydroxyalkanoate (E) is preferably produced by microorganisms. Specific examples of polyhydroxyalkanoate (E) include poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer resin and poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) copolymer resin. In particular, from the viewpoint of moldability and the physical properties of the resulting molded article, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer resin, i.e., PHBH, is preferred.

[0119] In polyhydroxyalkanoate (E), the composition ratio of 3-hydroxybutyrate (hereinafter sometimes referred to as 3HB) to the copolymerized comonomer, such as 3-hydroxyhexanoate (hereinafter sometimes referred to as 3HH), that is, the molar ratio of monomers in the copolymerized resin, is preferably 97 / 3 or higher, more preferably 95 / 5 or higher, and on the other hand, preferably 80 / 20 or lower, and more preferably 85 / 15 or lower, from the viewpoint of moldability and molded product quality. By keeping the monomer ratio within the above range, the difference between the molding temperature and the thermal decomposition temperature becomes larger, making molding easier, and the crystallization rate is within an appropriate range, thus ensuring productivity.

[0120] The ratio of each monomer in polyhydroxyalkanoate (E) can be measured by gas chromatography as follows. 20 mg of dried polyhydroxyalkanoate is placed in a sample container, 2 ml of sulfuric acid / methanol mixture (15 / 85 (weight ratio)) and 2 ml of chloroform are added, the container is sealed, and the mixture is heated at 100°C for 140 minutes to decompose the polyhydroxyalkanoate and obtain a methyl ester. After cooling, 1.5 g of sodium bicarbonate is added little by little to neutralize the mixture, and the mixture is left to stand until the generation of carbon dioxide stops. 4 ml of diisopropyl ether is added and thoroughly mixed, and the monomer unit composition of the sample decomposition product in the supernatant is analyzed by capillary gas chromatography to determine the ratio of each monomer in the copolymer resin.

[0121] Polyhydroxyalkanoates (E) can be produced by microorganisms such as Alcaligenes eutrophus AC32 strain, which was created by introducing a polyhydroxyalkanoate synthase gene from Aeromonas caviae into Alcaligenes eutrophus (international deposit under the Budapest Convention, international depositary authority: Patent Organism Depositary Center, National Institute of Advanced Industrial Science and Technology (1-1-1 Higashi, Tsukuba, Ibaraki Prefecture, Japan), original deposit date: August 12, 1996, transferred on August 7, 1997, deposit number FERM BP-6038 (transferred from original deposit FERM P-15786)) (J. Bacteriol., 179, 4821 (1997)).

[0122] Commercially available polyhydroxyalkanoates (E) can also be used. Commercially available polyhydroxyalkanoates (E) containing 3-hydroxybutyrate units and 3-hydroxyhexanoate units as the main constituent units include Kaneka Corporation's "PHBH X331N," "PHBH X131A," "PHBH X151A," and "PHBH 151C," among others.

[0123] In this embodiment, the aliphatic oxycarboxylic acid resin (D), including the polyhydroxyalkanoate (E) described above, is not limited to one type, but can be used by blending two or more aliphatic oxycarboxylic acid resins (D) that differ in the type of constituent units, the ratio of constituent units, the manufacturing method, physical properties, etc.

[0124] The polyester resin contained in the resin composition according to this embodiment may be used individually as one type of constituent unit, or two or more types may be used in any combination and ratio. Furthermore, the diol units, dicarboxylic acid units, and aliphatic oxycarboxylic acid units may be derived from compounds derived from petroleum or from compounds derived from plant materials, but it is preferable that they be derived from compounds derived from plant materials as it takes environmental issues into consideration.

[0125] Furthermore, if optical isomers exist for the aromatic compound component that yields these aromatic compound units, any of the D-isomer, L-isomer, or racemic mixture may be used. Also, the aromatic compound component is not limited to the examples above, as long as it can yield aromatic compound units. A single aromatic compound component may be used alone, or two or more may be used in any combination and ratio.

[0126] <<Other resins>> The resin composition according to this embodiment may contain resins other than polyester resins. The other resins are not particularly limited, and known resins can be used. Examples include polyurethane resins; polyimide resins; polyacrylic resins; acrylonitrile-butadiene-styrene resins; acrylonitrile-styrene resins; polycarbonate resins; polyethylene such as LDPE, MDPE, HDPE, LLDPE, and carboxyl-modified polyethylene; polyolefin resins such as polypropylene, polybutene, polypentene, ethylene-propylene copolymer, and ethylene-butylene copolymer; polyvinyl acetate resins; polyvinyl chloride resins; polyvinylidene chloride resins; polystyrene resins; epoxy resins; melamine resins; and polyamide resins such as nylon 6, nylon 11, nylon 66, nylon 12, nylon 610, and nylon 6T. These resins may be present individually or in combination of two or more types. The other resins are preferably biodegradable resins.

[0127] In the resin composition according to this embodiment, the polyester resin content (preferably the biodegradable polyester resin content) is preferably 5% by mass or more, and more preferably 10% by mass or more, from the viewpoint of the biodegradability of the resin composition. Furthermore, from the viewpoint of improving moldability, it is preferably 99.9% by mass or less, and more preferably 99.5% by mass or less. The resin contained in the resin composition according to this embodiment is preferably only a polyester resin, and more preferably only a biodegradable polyester resin. However, the resin contained in the resin composition according to this embodiment may be a resin other than polyester resin, or a polyester resin and a resin other than polyester resin may be used in combination, as long as its biodegradability is improved by the ionic nitrogen compound released from the specific composite described above.

[0128] (Physical properties of resins) Reduced viscosity of resin at 30°C η sp / c can be appropriately selected depending on the application, processing method, etc. Specifically, the reduced viscosity of the resin at 30°C is preferably 0.5 dL / g or more, more preferably 0.8 dL / g or more, even more preferably 1.0 dL / g or more, and particularly preferably 1.2 dL / g or more. On the other hand, it is preferably 4.0 dL / g or less, more preferably 3.0 dL / g or less, even more preferably 2.5 dL / g or less, and particularly preferably 2.3 dL / g or less. By keeping the reduced viscosity of the resin within the above range, the mechanical properties of the molded article can be ensured. Furthermore, the melt viscosity of the resin composition during molding will not place an excessive load on molding machines such as extruders and injection molders, thereby ensuring productivity.

[0129] The reduced viscosity of a resin can usually be measured by the following method. First, the resin is dissolved in a solvent to prepare a resin solution of concentration c (g / dL). Next, using a capillary viscometer (Ubbelohde viscometer), the solvent passage time t0 and the resin solution passage time t are measured at a temperature of 30.0°C ± 0.1°C, and the relative viscosity η is calculated based on the following equation (i). rel Calculate the relative viscosity η. rel Therefore, based on the following equation (ii), the specific viscosity η sp We seek η. rel = t / t0···(i) η sp =η rel -1 ···(ii) Specific viscosity obtained η sp By dividing by the concentration c (g / dL), the reduced viscosity η is obtained. sp The / c value can be calculated. Generally, a higher value indicates a larger molecular weight.

[0130] The molecular weight of the resin is usually measured by gel permeation chromatography (GPC). From the viewpoint of moldability and mechanical strength, the resin contained in the resin composition according to this embodiment preferably has a weight-average molecular weight (Mw) of monodisperse polystyrene as a standard substance within the following range. That is, the molecular weight of the resin is preferably 10,000 or more, more preferably 20,000 or more, even more preferably 30,000 or more, and particularly preferably 50,000 or more. The upper limit is preferably 2,500,000 or less, more preferably 1,000,000 or less, even more preferably 800,000 or less, particularly preferably 600,000 or less, especially preferably 500,000 or less, and most preferably 400,000 or less.

[0131] Furthermore, the weight-average molecular weight (Mw) of the polyhydroxyalkanoate resin is preferably 200,000 or more, more preferably 250,000 or more, and even more preferably 300,000 or more. On the other hand, the weight-average molecular weight (Mw) of the polyhydroxyalkanoate resin is preferably 2,500,000 or less, more preferably 2,000,000 or less, and even more preferably 1,000,000 or less.

[0132] The melt flow rate (MFR) of the resin can be evaluated based on the value measured at 190°C and a load of 2.16 kg according to JIS K 7210 (1999). From the viewpoint of moldability and mechanical strength, the MFR of the resin contained in the resin composition according to this embodiment is preferably within the following range: preferably 0.1 g / 10 min or more, and more preferably 1 g / 10 min or more. On the other hand, the MFR of the resin is preferably 100 g / 10 min or less, more preferably 80 g / 10 min or less, even more preferably 50 g / 10 min or less, particularly preferably 40 g / 10 min or less, and most preferably 30 g / 10 min or less. Note that the MFR of the resin can be adjusted by the molecular weight, etc.

[0133] By setting the melting point of the resin within the following ranges, good moldability can be ensured. Specifically, the melting point of the resin is preferably 50°C or higher, more preferably 70°C or higher, even more preferably 75°C or higher, and particularly preferably 80°C or higher. On the other hand, it is preferably 270°C or lower, more preferably 200°C or lower, even more preferably 160°C or lower, particularly preferably 150°C or lower, especially preferably 140°C or lower, and most preferably 130°C or lower. If the resin has multiple melting points, it is preferable that at least one of them is within the above ranges.

[0134] Furthermore, regarding the melting point of the polyhydroxyalkanoate resin, it is preferably 100°C or higher, more preferably 110°C or higher, while it is preferably 180°C or lower, more preferably 170°C or lower, and particularly preferably less than 160°C.

[0135] The tensile modulus of the resin is preferably 50 MPa or higher, more preferably 100 MPa or higher, and more preferably 2000 MPa or lower, and more preferably 500 MPa or lower, as this ensures good moldability and impact strength. The tensile modulus can be measured by the following method. A heat-pressed resin sheet is prepared and punched out into a No. 8 dumbbell shape to create a test specimen. Specifically, a metal frame (SUS304, outer diameter 110 mm, inner diameter 70 mm, thickness 0.2 mm) with surface release treatment is placed on a 150 mm x 150 mm PTFE tape. 1.6 g of resin is measured and placed inside this metal frame, and another 150 mm x 150 mm PTFE tape is placed on top of it. The resin sandwiched between two iron plates (160 mm x 160 mm, thickness 3 mm) is then heat-pressed using a heat press machine, followed by cooling and pressing using a cooling press machine to obtain a heat-pressed sheet measuring 70 mm x 70 mm x 0.2 mm thick. The heat press temperature is 180°C, and the heat press time is 2 minutes of preheating followed by 2 minutes of pressing. The cooling press temperature is 20°C, and the cooling press time is 2 minutes. This hot-pressed sheet is uniaxially stretched at a speed of 50 mm / min, and the initial slope of the resulting stress-strain curve is determined as the tensile modulus. The method for adjusting the melting point and tensile modulus of the resin is not particularly limited. These can be adjusted by the type of copolymerization components and their copolymerization ratio.

[0136] When the temperature of a resin exceeds its glass transition temperature, the molecular chains become more mobile. Therefore, when a resin is biodegraded, if the glass transition temperature is lower than the temperature of the environment in which the resin is placed, such as in the ocean, the crystal structure of the resin loosens, allowing the molecular main chain to rotate and vibrate, thus facilitating biodegradation. For this reason, resins with low glass transition temperatures are presumed to be easily biodegraded. In particular, if the glass transition temperature of a resin is 40°C or lower, nitrogen compounds released from the ion adsorption complex in seawater become a nutrient source for microorganisms, making it even easier to biodegrade. Accordingly, the glass transition temperature (Tg) of the resin is preferably 40°C or lower, more preferably 30°C or lower, even more preferably 25°C or lower, and particularly preferably 20°C or lower. The glass transition temperature can be measured by the following method. 10 mg of resin is placed in an aluminum sample container to prepare the sample for measurement. Then, using a DSC, the temperature is increased at a rate of 10°C / min under a nitrogen atmosphere to obtain a DSC chart. The glass transition temperature is determined from the baseline shift located at a lower temperature than the peak indicating the melting point in this chart. Specifically, the glass transition temperature is defined as the intersection point of the lower-temperature baseline and the point of junction with the inflection point.

[0137] The acid value of the resin is preferably low because it makes hydrolysis less likely and improves storage stability. Specifically, it is preferably 250 eq / t or less, more preferably 150 eq / t or less, even more preferably 100 eq / t or less, and particularly preferably 50 eq / t or less. The acid value can be measured by the following method. Weigh 0.4 g of resin accurately, add 25 mL of benzyl alcohol, and heat to 195°C, stirring to dissolve. Once the resin is dissolved, cool the container holding the resin solution in an ice bath, and add 2 mL of ethanol to the container. Titrate with a 0.01 N sodium hydroxide solution of benzyl alcohol (let the titration volume be A (ml)). Next, the same measurement was performed using only benzyl alcohol, and this was used as the blank value (B(ml)). The acid value is calculated using the following formula. Terminal acid value (μeq / g)=(AB)×F×10 / W A (ml): Measured titer amount B (ml): Blank titration volume F: 0.01N NaOH benzyl alcohol your period factor W(g): Sample weight

[0138] <Other ingredients> The resin composition according to this embodiment may contain other components such as fillers, plasticizers, antistatic agents, antioxidants, light stabilizers, ultraviolet absorbers, dyes, pigments, hydrolysis inhibitors, nucleating agents, antiblocking agents, weathering agents, heat stabilizers, flame retardants, mold release agents, antifogging agents, surface wetting improvers, incineration aids, dispersion aids, various surfactants, slip agents, freshness preservatives, antibacterial agents, and other additives, as long as the effects of the present invention are not significantly impaired. If these components are included, there may be only one type of component or two or more types.

[0139] If other components are included in the resin composition, their content is preferably 40% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, and particularly preferably 5% by mass or less, based on the total amount of the resin composition, from the viewpoint of not impairing the properties of the resin composition. There is no particular lower limit to the content of other components.

[0140] [Method for producing resin composition] The method for producing the resin composition according to this embodiment is not particularly limited. The resin composition according to this embodiment is obtained by blending a resin with the specific composite described above and other components as needed. The resin composition can be produced, for example, by blending each component in predetermined proportions simultaneously or in any order, and mixing or kneading them using a mixer such as a tumbler, V-type blender, Nauter mixer, Banbury mixer, kneading roll, or extruder, preferably by melt kneading. Alternatively, the resin and the specific composite described above can be dissolved or dispersed in a solvent, and the solvent can be removed to produce the composition.

[0141] From the viewpoint of improving the biodegradability and biodegradation rate of the resin composition, particularly the initial biodegradation rate, it is preferable that the above-mentioned specific composite is uniformly dispersed in the resin composition. From this viewpoint, the resin composition according to this embodiment is preferably manufactured by kneading, and more preferably by melt kneading.

[0142] The kneader used for mixing may be a melt kneader. The extruder may be either a twin-screw extruder or a single-screw extruder, but a twin-screw extruder is more preferred.

[0143] When performing melt mixing, the melt mixing temperature is preferably 80°C or higher, and more preferably 100°C or higher. The upper limit is preferably 220°C or lower, and more preferably 210°C or lower. Within this temperature range, melt mixing can be performed in a short time, deterioration of the resin and deterioration of color tone are less likely to occur, and the resulting resin composition tends to have better practical physical properties such as impact resistance and heat and humidity resistance. The melting and mixing time is not particularly limited, but it is desirable to perform it for a short time to minimize resin degradation. Specifically, the melting and mixing time is preferably 10 seconds or more, and more preferably 30 seconds or more. The upper limit is preferably 20 minutes or less, and more preferably 15 minutes or less.

[0144] [Biodegradability] The resin composition according to this embodiment and the molded article obtained using it are preferably biodegradable. In particular, the resin composition according to this embodiment and the molded article obtained using it are preferably biodegradable in seawater, where resins are generally considered difficult to biodegrade (marine biodegradability). In this specification, the degree of biodegradability is calculated as the ratio of biological oxygen demand (BOD) to theoretical oxygen demand (ThOD). For example, biodegradation in seawater is measured in accordance with ISO 14851:1999 (Plastics - Determination of aerobic ultimate biodegradability in aqueous culture solutions - Method by measurement of carbon dioxide emissions); and biodegradation in soil is measured in accordance with ISO 17556:2003 (Plastics - Determination of aerobic ultimate biodegradability in soil by measurement of oxygen consumption or carbon dioxide emissions using a respiration meter).

[0145] [Molded body] The resin composition according to this embodiment can be molded by various molding methods applicable to general-purpose plastics. Examples of molding methods include compression molding (compression molding, lamination molding, stampable molding), injection molding, extrusion molding, co-extrusion molding (film molding, lamination molding, pipe molding, wire / cable molding, profile molding by inflation method or T-die method), hot press molding, hollow molding (various blow molding methods), calendering, solid molding (uniaxial stretching, biaxial stretching, roll rolling, stretch-oriented nonwoven fabric molding), thermoforming (vacuum forming, pressure forming), plastic processing, powder molding (rotational molding), and various nonwoven fabric molding methods (dry method, adhesive method, entanglement method, spunbond method, etc.). Among these, injection molding, extrusion molding, compression molding, or hot press molding are preferably applied, and injection molding or extrusion molding are more preferably applied. In terms of specific shapes, application to sheets, films, and containers is preferred. A molded article containing any of the resin compositions described above is also preferred.

[0146] Furthermore, molded articles obtained using the resin composition according to this embodiment can be subjected to various secondary processing for the purpose of imparting chemical functions, electrical functions, magnetic functions, mechanical functions, friction / wear / lubrication functions, optical functions, thermal functions, biocompatibility, and other surface functions. Examples of secondary processing include embossing, painting, bonding, printing, metallizing (plating, etc.), machining, and surface treatment (antistatic treatment, corona discharge treatment, plasma treatment, photochromism treatment, physical vapor deposition, chemical vapor deposition, coating, etc.).

[0147] [Application] Molded articles obtained using the resin composition according to this embodiment are suitably used in a wide range of applications, such as packaging materials for liquids, powders, and solids of various foods, pharmaceuticals, and general merchandise, as well as agricultural materials and construction materials. Specific applications include injection-molded articles (e.g., trays for fresh food, fast food containers, coffee capsule containers, cutlery, outdoor leisure products, etc.), extruded articles (e.g., films, sheets, fishing lines, fishing nets, vegetation nets, sheets for secondary processing, water-retaining sheets, etc.), and hollow molded articles (bottles, etc.). Furthermore, other examples include agricultural films, coating materials, fertilizer coating materials, seedling pots, laminate films, boards, stretched sheets, monofilaments, nonwoven fabrics, flat yarns, staples, crimped fibers, crimped tapes, split yarns, composite fibers, blow bottles, shopping bags, garbage bags, compost bags, cosmetic containers, detergent containers, bleach containers, ropes, binding materials, sanitary coverstock materials, insulated boxes, cushioning films, multifilaments, synthetic paper, and for medical use, surgical threads, sutures, artificial bones, artificial skin, DDS such as microcapsules, wound dressings, etc. The molded articles are particularly suitable as food packaging films, fresh food trays, fast food containers, lunch boxes, and other food containers. [Examples]

[0148] The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited to the following examples unless it exceeds its gist. The various manufacturing conditions or evaluation result values ​​in the following examples are intended to represent preferred upper or lower limits in embodiments of the present invention, and the preferred range may be defined by a combination of the aforementioned upper or lower limits and the values ​​of the following examples or between examples.

[0149] <Measurement of the isoelectric point of ionic nitrogen compounds> Isoelectric point of precast gel (SERVAGel) TMIsoelectric focusing (IEF) was measured using SERVA Electrophoresis (Heidelberg). The isoelectric points of ionic nitrogen compounds were calculated visually using a SERVA IEF Marker 3-10 mixture.

[0150] <Manufacturing of polyester resin> (PBSSe) 1,4-Butanediol (100.1 g), succinic acid (75.0 g), sebacic acid (32.1 g), trimethylolpropane (0.34 g), and titanium tetrabutoxide (0.50 g) were heated under nitrogen at 200°C for 2 hours with stirring. Subsequently, the temperature was raised to 250°C under reduced pressure and reacted for 5 hours and 15 minutes. The resulting polymer was extracted in strand form into water and cut to obtain pellet-shaped PBSSe. The reduced viscosity of PBSSe was measured according to the measurement method described below and was found to be 1.8 dL / g. Furthermore, the glass transition temperature and acid value were measured according to the measurement method described below and were -30°C and 28 eq / t, respectively. 1 The molar ratio of succinic acid units to sebacic acid units, determined by 1H-NMR (nuclear magnetic resonance spectroscopy), was 80 / 20.

[0151] (Method for measuring reduced viscosity) A resin solution was prepared by dissolving the resin in a 1:1 (by weight) mixed solvent of phenol and tetrachloroethane to a concentration of 0.5 g / dL. Next, the reduced viscosity of the resin solution at 30°C was measured using an Ubbelohde viscous tube, and the reduced viscosity was calculated based on the results.

[0152] (Method for measuring glass transition temperature) 10 mg of each resin was placed in an aluminum sample container to prepare the measurement sample. Next, using a Hitachi High-Tech Science Corporation "DSC6220," the temperature was increased from -100°C to 160°C at a rate of 10°C / min under a nitrogen atmosphere to obtain a DSC chart. The glass transition temperature was determined from the baseline shift located at a temperature lower than the peak indicating the melting point in this chart. Specifically, the intersection of the lower-temperature baseline and the point of junction with the inflection point was defined as the glass transition temperature.

[0153] (Method for measuring acid value) The titration was performed using the GT100 automatic titrator manufactured by Iwate Toa DKK Co., Ltd., following the method described above.

[0154] <Method for manufacturing the composite> (Manufacturing Example 1) Cationic L-histidine hydrochloride (monohydrate) (manufactured by Kishida Chemical Co., Ltd., isoelectric point (pI) 7.59) was used as the ionic nitrogen compound, and an anionic acid clay (Mizuka Ace #20, manufactured by Mizusawa Chemical Industry Co., Ltd., a support with anionic functional groups) was used as the support. First, an aqueous solution of an ionic nitrogen compound with a concentration of 0.05% by mass was prepared. The absorbance of the ionic nitrogen compound in the aqueous solution was measured using an ultraviolet (UV) spectroscopy device (initial concentration C0). The absorbance at a wavelength of 190 nm, where absorption from amino acids is observed, was used. Next, 50 mg of a support was added to 4 ml of the aqueous solution of the ionic nitrogen compound and immersed for 6 hours to adsorb the ionic nitrogen compound onto the support. After filtration, the solid was recovered and dried to produce a composite. In this composite, the ionic nitrogen compound is adsorbed onto the support by ionic bonds. Furthermore, the absorbance of the aqueous solution of the ionic nitrogen compound (filtrate) after adsorption was measured at a wavelength of 190 nm (at the concentration C after adsorption). IE Since absorbance is proportional to the concentration of ionic nitrogen compounds, the initial concentration C0 and the concentration after adsorption C0 are related. IE The adsorption rate of the ionic nitrogen compound to the support was calculated from the change in absorbance before and after the addition of the support. The adsorption rate was calculated using the following formula. A Shimadzu UV2600 ultraviolet-visible light spectrophotometer was used for UV measurements. [(C0-C IE ) / C0]×100

[0155] The resulting composites were immersed in either pure water or 3.5% by mass saline solution at 23°C for at least one hour, and the degree to which ionic nitrogen compounds were desorbed (desorption rate) was calculated by UV measurement, similar to the method used to calculate the adsorption rate of ionic nitrogen compounds described above. The desorption rate was calculated with the amount of ionic nitrogen compounds adsorbed on the carrier as 100%.

[0156] [Table 1]

[0157] As shown in Table 1, the composite of Production Example 1 had a high adsorption rate of ionic nitrogen compounds. Furthermore, while the desorption rate of ionic nitrogen compounds was small in pure water, the desorption rate of ionic nitrogen compounds was high in 3.5% by mass saline solution.

[0158] (Manufacturing example 2) Cationic spermine 4 hydrochloride (manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the ionic nitrogen compound, and an anionic acid clay (Mizuka Ace #20, manufactured by Mizusawa Chemical Industry Co., Ltd., a support with anionic functional groups) was used as the support. First, an aqueous solution of an ionic nitrogen compound with a concentration of 0.05% by mass was prepared. Next, 50 mg of a support was added to 4 ml of the aqueous solution of the ionic nitrogen compound, and the mixture was immersed for 6 hours to adsorb the ionic nitrogen compound onto the support. After filtration, the solid was recovered and dried to produce a composite. In this composite, the ionic nitrogen compound is adsorbed onto the support by ionic bonds.

[0159] <Examples 1-3> (Method for creating resin compositions) The pulverized resins listed in the table below and the dried composites listed in the table below were blended in a ratio of resin (95% by mass) to composite (5% by mass). The mixture was then placed in a small twin-screw kneader (DSM's "Xplore MC15HT Micro Compounder") and melt-kneaded at 120°C for 3 minutes under a nitrogen atmosphere. The resulting mixture was pulverized to a particle size (by sieving method) of 250 μm or less to obtain the resin compositions of Examples 1 to 3.

[0160] (Biodegradation assessment) The biodegradability of the resins and the resin compositions of Examples 1-3 was measured in accordance with ISO 14851 as follows. 30 mg of the resin composition of each example was placed in a 510 mL brown bottle, to which 100 mL of a mixture of standard test culture solution prepared in accordance with ISO 14851 and seawater (natural seawater collected from Tokyo Bay) was added. A pressure sensor (WTW, OxiTop®-C type) was attached to the brown bottle, and the test solution was stirred with a stirrer for 30 days under a constant temperature environment of 25°C. The degree of biodegradation (%) was calculated based on BOD measurement. The biodegradability of the resin (PBSSe or PBSA) and the biodegradability of the resin composition containing the composite were measured, and the degree of improvement in the biodegradability of the resin composition containing the composite relative to the biodegradability of the resin (biodegradability of the resin composition / biodegradability of the resin) was calculated. The PBSSe used was the PBSSe produced in the section on polyester resin production described above. PBSA used was BioPBS® FD92PM (manufactured by PTT MCC Biochem).

[0161] [Table 2]

[0162] As shown in the table above, the biodegradability was improved by including a composite in the carrier in which an ionic nitrogen compound represented by formula (I) and having a molecular weight of less than 10,000 is adsorbed by non-covalent bonds. Furthermore, a comparison between Example 2 and Example 3 reveals that the complex from Production Example 1 tends to have a higher biodegradation-enhancing effect than the complex from Production Example 2. The higher biodegradation-enhancing effect of the L-histidine hydrochloride (monohydrate) complex used in Production Example 1 compared to the spermine 4 hydrochloride complex used in Production Example 2 is thought to be due to differences in the biodegradation-enhancing effect of the substances themselves, their desorption properties with salt, and their hydrophilic / hydrophobic properties.

[0163] <Examples 4 and 5> The resin compositions listed in the table below were used to create press films with a thickness of approximately 100 μm using Toyo Seiki's Mini Test Press MP-WNH, and molded articles of Examples 4 and 5 were obtained. Using the same method as in Examples 1-3, the biodegradability of the resin (PBSA) and the biodegradability of each molded product were measured, and the degree of improvement in the biodegradability of the molded product relative to the biodegradability of the resin (biodegradability of the molded product / biodegradability of the resin) was calculated.

[0164] [Table 3]

[0165] As shown in the table above, the biodegradability was improved by including a composite in the carrier in which an ionic nitrogen compound represented by formula (I) and having a molecular weight of less than 10,000 is adsorbed by non-covalent bonds. Furthermore, a comparison of Example 4 and Example 5 reveals that the composite from Production Example 1 (Example 4) tends to have a higher biodegradation-enhancing effect than the composite from Production Example 2 (Example 5).

Claims

1. A composite in which an ionic nitrogen compound represented by formula (I) and having a molecular weight of less than 10,000 is adsorbed on a carrier by non-covalent bonds, resin and A resin composition containing the following: 【Chemistry 1】 (In the formula, R, R', R'', and R''' each independently represent a hydrogen atom or a monovalent organic group which may have a substituent.)

2. The monovalent organic group which may have substituents is a hydrocarbon group which may contain one or more atoms selected from the group consisting of elements of groups 15 to 17. The resin composition according to claim 1.

3. The support has an ionic functional group, The resin composition according to claim 1 or 2, wherein the ionic nitrogen compound is adsorbed onto the support by ionic bonding with the ionic functional group of the support.

4. The resin composition according to claim 1 or 2, wherein the ionic nitrogen compound is an amino acid or a polyamine.

5. The resin composition according to claim 1 or 2, wherein the isoelectric point of the ionic nitrogen compound is 7.0 or higher.

6. The resin composition according to claim 1 or 2, wherein the support comprises a naturally derived material.

7. The resin composition according to claim 1 or 2, wherein the support comprises at least one selected from acid clay, activated clay, bentonite, montmorillonite, and silica.

8. The resin composition according to claim 1 or 2, wherein the resin is a biodegradable resin.

9. The resin composition according to claim 8, wherein the biodegradable resin is a polyester resin.

10. The resin composition according to claim 9, wherein the polyester resin contains aliphatic diol units.

11. The resin composition according to claim 9, wherein the polyester resin contains aliphatic dicarboxylic acid units.

12. A molded article obtained using the resin composition described in claim 1 or 2.

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