Tubular bodies, straws, cotton swabs and balloon sticks

Abstract

To provide a tubular body having high biodegradability at a room temperature compared to a conventional tubular molded product using a biodegradable resin, excellent in marine biodegradability, excellent in moldability when obtaining a tubular molded product, and also excellent in mechanical characteristics such as piercing strength, and characteristics such as heat resistance.SOLUTION: A tubular body comprises an aliphatic polyester resin composition which contains an aliphatic polyester resin (A) including a repeating unit derived from aliphatic diol, and a repeating unit derived from aliphatic dicarboxylic acid as the main constitutional units, polyhydroxyalkanoate (B) and an inorganic filler (C). The polyhydroxyalkanoate (B) is a copolymer which includes a 3-hydroxybutyrate unit and a 3-hydroxyhexanoate unit as the main constitutional units. A content ratio of the inorganic filler (C) to the total amount of the aliphatic polyester resin (A), the polyhydroxyalkanoate (B) and the inorganic filler (C) is 5-50 mass%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a tubular body formed by molding an aliphatic polyester resin composition, and to a straw, a cotton swab, and a balloon stick using the tubular body. [Background technology]

[0002] In recent years, there has been active development of biodegradable plastics as a solution to the problems of plastic waste, which pose a significant burden on the global environment, including its impact on ecosystems, the generation of harmful gases during combustion, and global warming due to the large amount of heat generated by combustion. In particular, the carbon dioxide emitted when plant-based biodegradable plastics are burned is carbon that was originally present in the air, and does not increase the amount of carbon dioxide in the atmosphere. This is called carbon neutrality, and is considered important under the Kyoto Protocol, which imposed carbon dioxide reduction targets, and active use of biodegradable plastics is desired.

[0003] Recently, from the viewpoints of biodegradability and carbon neutrality, aliphatic polyester resins have been attracting attention as plant-derived plastics, and in particular polyhydroxyalkanoate (hereinafter sometimes referred to as PHA) resins, and among PHA resins, poly(3-hydroxybutyrate) homopolymer resin (hereinafter sometimes referred to as PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer resin (hereinafter sometimes referred to as PHBV), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer resin (hereinafter sometimes referred to as PHBH), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer resin, and polylactic acid have been attracting attention.

[0004] For example, Patent Document 1 discloses a molded article made of an aliphatic polyester resin composition containing a compound having an amide bond in polyhydroxyalkanoate and pentaerythritol, and describes that the moldability in molding processes such as injection molding and sheet processing is improved. Meanwhile, in recent years, the use of biodegradable resins has also been investigated for tubular molded products, such as straws, tubes, hoses, etc. For example, Patent Document 2 discloses a straw that contains polylactic acid as an essential component and also contains polybutylene succinate adipate, which is an aliphatic polyester, or polybutylene adipate terephthalate, which is an aliphatic / aromatic polyester, and Patent Document 3 discloses a straw molded from a resin that contains polylactic acid, polybutylene adipate terephthalate, and an inorganic filler. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2014 / 068943 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-350530 [Patent Document 3] Japanese Patent Application Laid-Open No. 2011-208040 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, the social trend toward stronger environmental protection, particularly the environmental pollution caused by the disposal of used plastic products (particularly the impact of microplastics caused by the disposal of used plastic products in the ocean) has led to a demand for fully biodegradable resins, rather than only partially biodegradable. Furthermore, in terms of the biodegradation environment, biodegradability is required not only in aerobic composting environments (soil) at relatively high temperatures (58°C or higher), but also in aerobic composting environments (soil) at room temperature (28°C) and in the ocean. If biodegradable resins could be biodegraded not only at room temperature but also in the ocean (marine biodegradability), then, for example, straws, tubes, and hoses made of biodegradable resins could be composted at home after use, and furthermore, biodegradation in the ocean would eliminate the adverse impact of microplastics on marine life.

[0007] The above-mentioned Patent Documents 2 and 3 disclose the use of biodegradable resins such as polylactic acid and polybutylene succinate adipate or the aliphatic-aromatic polyester polybutylene adipate terephthalate for straws, but the biodegradable resins proposed therein have low biodegradability at room temperature and in the ocean, and do not satisfy the rapidly increasing demand for reduced environmental impact. Furthermore, Patent Document 1 discloses a molded product using PHBH, but this molded product is hard and brittle, resulting in poor impact resistance and puncture resistance, as well as poor stability during molding.

[0008] The present invention has been made in consideration of the above background, and aims to provide a tubular body that has a higher degree of biodegradability at room temperature and excellent marine biodegradability compared to tubular molded products made from conventional biodegradable resins, and that also has excellent moldability when obtaining tubular molded products, as well as excellent mechanical properties such as puncture strength and heat resistance. [Means for solving the problem]

[0009] As a result of extensive research to solve the above-mentioned problems, the present inventors have found that a tubular body molded from an aliphatic polyester resin composition containing an aliphatic polyester resin (A) containing, as main structural units, a repeating unit derived from an aliphatic diol and a repeating unit derived from an aliphatic dicarboxylic acid, a polyhydroxyalkanoate (B), and further an inorganic filler (C) in a predetermined ratio has excellent moldability, a high degree of biodegradability at room temperature, excellent marine biodegradability, and excellent mechanical properties such as puncture strength and heat resistance, thereby completing the present invention.

[0010] [1] A tubular body using an aliphatic polyester resin composition comprising an aliphatic polyester resin (A) containing, as main structural units, repeating units derived from an aliphatic diol and repeating units derived from an aliphatic dicarboxylic acid, a polyhydroxyalkanoate (B), and an inorganic filler (C), wherein the polyhydroxyalkanoate (B) is a copolymer containing, as main structural units, 3-hydroxybutyrate units and 3-hydroxyhexanoate units, and the content of the inorganic filler (C) relative to the total amount of the aliphatic polyester resin (A), the polyhydroxyalkanoate (B), and the inorganic filler (C) is 5 to 50 mass%.

[0011] [2] The tubular body according to [1], wherein the inorganic filler (C) is one or more selected from the group consisting of anhydrous silica, calcium carbonate, talc, and zeolite.

[0012] [3] The tubular body according to [1] or [2], wherein the proportion of repeating units derived from succinic acid in all repeating units derived from dicarboxylic acids contained in the aliphatic polyester resin (A) is 5 mol% or more and 100 mol% or less.

[0013] [4] The tubular body according to any one of [1] to [3], which is an extrusion molded body.

[0014] [5] A straw made of the tubular body according to any one of [1] to [4].

[0015] [6] A cotton swab comprising the tubular body according to any one of [1] to [4].

[0016] [7] A balloon stick comprising the tubular body according to any one of [1] to [4].

[0017] [8] In the marine biodegradability test (ASTM D6691), the absolute or relative biodegradability of the tubular body is 60% or more after 100 days in seawater at a temperature of 30°C ± 2°C.

[0018] [9] A straw comprising the tubular body described in [8]. [Effects of the Invention]

[0019] According to the present invention, there is provided a tubular body that has a high degree of biodegradability at room temperature and in the sea (marine biodegradability), and that is excellent in formability as well as in mechanical properties such as puncture strength and heat resistance, etc. Because the tubular body of the present invention has a high degree of biodegradability even at room temperature and an even higher degree of marine biodegradability, it is expected that even when used in disposable straws, cotton swabs, balloon sticks, etc., it will be completely biodegradable in the sea and will have a significantly reduced impact on marine organisms compared to conventional plastic products. DETAILED DESCRIPTION OF THE INVENTION

[0020] The following describes in detail the embodiments of the present invention, but the present invention is not limited to the following description and can be modified and implemented as desired within the scope that does not deviate from the gist of the present invention. In this specification, when "~" is used to express a numerical value or a physical property value, the values ​​before and after the "~" are included. In this specification, "mass %" and "parts by mass" have the same meaning as "weight %" and "parts by weight", respectively.

[0021] The tubular body of the present invention is obtained by molding an aliphatic polyester resin composition (hereinafter sometimes referred to as "the aliphatic polyester resin composition of the present invention") that contains an aliphatic polyester resin (A) containing, as main structural units, repeating units derived from an aliphatic diol and repeating units derived from an aliphatic dicarboxylic acid, a polyhydroxyalkanoate (B), and an inorganic filler (C), wherein the polyhydroxyalkanoate (B) is a copolymer containing, as main structural units, 3-hydroxybutyrate units and 3-hydroxyhexanoate units, and the content of the inorganic filler (C) relative to the total amount of the aliphatic polyester resin (A), the polyhydroxyalkanoate (B), and the inorganic filler (C) is 5 to 50 mass%.

[0022] Furthermore, the tubular body of the present invention is a tubular body that has an absolute or relative biodegradability of 60% or more after 100 days in a seawater temperature of 30°C ± 2°C in a marine biodegradability test (ASTM D6691), and is preferably a tubular body molded from the aliphatic polyester resin composition of the present invention. Furthermore, it can be suitably used for straws, and when used as a straw, it is extremely useful as a marine biodegradable straw. The higher the biodegradability, the better, and there is no particular upper limit.

[0023] In the present invention, an aliphatic diol refers to an aliphatic hydrocarbon group to which two hydroxyl groups are bonded. As the aliphatic hydrocarbon group, a linear aliphatic hydrocarbon group is usually used, but it may have a branched structure, a cyclic structure, or a plurality of these. Furthermore, an aliphatic dicarboxylic acid refers to an aliphatic hydrocarbon group to which two carboxyl groups are bonded. As the aliphatic hydrocarbon group, a straight-chain aliphatic hydrocarbon group is usually used, but it may have a branched structure, a cyclic structure, or a plurality of these.

[0024] The aliphatic polyester resin (A) contained in the aliphatic polyester resin composition of the present invention is a polymer having repeating units, and each repeating unit is also called a compound unit corresponding to the compound from which the repeating unit is derived. For example, a repeating unit derived from an aliphatic diol is also called an "aliphatic diol unit," and a repeating unit derived from an aliphatic dicarboxylic acid is also called an "aliphatic dicarboxylic acid unit." The "main structural unit" in the aliphatic polyester resin (A) generally refers to a structural unit that accounts for 80 mass% or more of the aliphatic polyester resin (A), and there are cases in which no structural units other than the main structural unit are contained. The same applies to the "main structural unit" in the polyhydroxyalkanoate (B).

[0025] [mechanism] The aliphatic polyester resin (A) and polyhydroxyalkanoate (B) contained in the aliphatic polyester resin composition of the present invention are highly biodegradable at room temperature and in the sea, and therefore the tubular body of the present invention made from the aliphatic polyester resin composition of the present invention containing the aliphatic polyester resin (A) and polyhydroxyalkanoate (B) as resin components has excellent biodegradability at room temperature and in the sea. Furthermore, the combined use of the aliphatic polyester resin (A) and polyhydroxyalkanoate (B) can improve moldability and provide excellent heat resistance. The aliphatic polyester resin composition of the present invention contains an inorganic filler (C) in a predetermined proportion in addition to the aliphatic polyester resin (A) and the polyhydroxyalkanoate (B), thereby imparting appropriate rigidity and making the composition excellent in puncture resistance. Furthermore, the addition of inorganic filler (C) increases the surface area of ​​the molded article, and as decomposition is accelerated, the inorganic filler falls off, increasing the contact area with the decomposing enzymes produced by the microorganisms, thereby accelerating the biodegradation rate of the aliphatic polyester resin (A) and the polyhydroxyalkanoate (B). Furthermore, inorganic filler (C) also functions as a nucleating agent, thereby effectively improving moldability. Therefore, by including inorganic filler (C) in a specified proportion, it is possible to provide tubular articles with even better room temperature biodegradability and marine biodegradability, with good moldability and productivity.

[0026] [Aliphatic polyester resin composition] The aliphatic polyester resin composition of the present invention, which contains an aliphatic polyester resin (A), a polyhydroxyalkanoate (B), and preferably further contains an inorganic filler (C), will be described below.

[0027] <Aliphatic polyester resin (A)> The aliphatic polyester resin (A) used in the present invention (hereinafter sometimes referred to as "polyester resin (A)") is an aliphatic polyester resin containing aliphatic diol units and aliphatic dicarboxylic acid units as main constituent units.

[0028] The polyester resin (A) used in the present invention preferably has a proportion of succinic acid units in all dicarboxylic acid units of 5 mol % or more and 100 mol % or less. The polyester resin (A) may be a mixture of aliphatic polyester resins having different amounts of succinic acid units. For example, it is possible to blend an aliphatic polyester resin that does not contain aliphatic dicarboxylic acid units other than succinic acid (containing only succinic acid units as aliphatic dicarboxylic acid units) with an aliphatic polyester resin that contains aliphatic dicarboxylic acid units other than succinic acid, and use the blend to adjust the amount of succinic acid units in the polyester resin (A) within the above-mentioned preferred range.

[0029] More specifically, the polyester resin (A) is a polyester resin containing an aliphatic diol unit represented by the following formula (1) and an aliphatic dicarboxylic acid unit represented by the following formula (2). -OR 1 -O- (1) -OC-R 2 -CO- (2)

[0030] In formula (1), R 1 represents a divalent aliphatic hydrocarbon group. 2 represents a divalent aliphatic hydrocarbon group. The aliphatic diol unit and the aliphatic dicarboxylic acid unit represented by the above formula (1) and (2) may be derived from a compound derived from petroleum or a compound derived from plant raw materials, but are preferably derived from a compound derived from plant raw materials.

[0031] When the polyester-based resin (A) is a copolymer, the polyester-based resin (A) may contain two or more types of aliphatic diol units represented by formula (1), and the polyester-based resin (A) may contain two or more types of aliphatic dicarboxylic acid units represented by formula (2).

[0032] As mentioned above, the aliphatic dicarboxylic acid units represented by formula (2) preferably contain succinic acid units in an amount of 5 mol % to 100 mol % based on the total dicarboxylic acid units. By setting the amount of succinic acid constituent units in the polyester resin (A) within the above-mentioned range, it is possible to obtain a biodegradable resin composition that has improved moldability and excellent heat resistance and decomposability. For the same reason, the amount of succinic acid units in the polyester resin (A) is preferably 10 mol % or more, more preferably 50 mol % or more, even more preferably 64 mol % or more, and particularly preferably 68 mol % or more based on the total dicarboxylic acid units. Hereinafter, the ratio of succinic acid units to all dicarboxylic acid units in the polyester resin (A) may be referred to as the "succinic acid unit amount." Furthermore, it is more preferable that the aliphatic dicarboxylic acid units represented by formula (2) contain one or more types of aliphatic dicarboxylic acid units other than succinic acid in an amount of 5 mol % to 50 mol % based on the total dicarboxylic acid units. By copolymerizing aliphatic dicarboxylic acid units other than succinic acid within the above-mentioned predetermined range, the crystallinity of the polyester resin (A) can be reduced, and biodegradability can be increased. For the same reason, the amount of aliphatic dicarboxylic acid units other than succinic acid in the polyester resin (A) is preferably 10 mol % to 45 mol %, more preferably 15 mol % to 40 mol %, based on the total dicarboxylic acid units.

[0033] The aliphatic diol that provides the diol unit represented by formula (1) is not particularly limited, but from the viewpoint of moldability and mechanical strength, an aliphatic diol having 2 to 10 carbon atoms is preferred, and an aliphatic diol having 4 to 6 carbon atoms is particularly preferred. Examples include ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,4-cyclohexanedimethanol, with 1,4-butanediol being particularly preferred. Two or more of the above aliphatic diols can also be used.

[0034] The aliphatic dicarboxylic acid component that provides the aliphatic dicarboxylic acid unit represented by formula (2) is not particularly limited, but is preferably an aliphatic dicarboxylic acid having 2 to 40 carbon atoms or a derivative thereof such as an alkyl ester, and particularly preferably an aliphatic dicarboxylic acid having 4 to 10 carbon atoms or a derivative thereof such as an alkyl ester. Examples of aliphatic dicarboxylic acids having 4 to 10 carbon atoms other than succinic acid or derivatives thereof such as an alkyl ester include adipic acid, suberic acid, sebacic acid, dodecanedioic acid, dimer acid, etc., and derivatives thereof such as alkyl esters. Among these, adipic acid and sebacic acid are preferred, and adipic acid is particularly preferred. Note that two or more types of the aliphatic dicarboxylic acid components can be used, and in this case, a combination of succinic acid and adipic acid is preferred.

[0035] The polyester resin (A) may have a repeating unit (aliphatic oxycarboxylic acid unit) derived from an aliphatic oxycarboxylic acid. Specific examples of the aliphatic oxycarboxylic acid component that provides the aliphatic oxycarboxylic acid unit include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 6-hydroxycaproic acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, and the like, as well as derivatives thereof, such as lower alkyl esters or intramolecular esters. When optical isomers exist, they may be in the D-form, L-form, or racemic form, and may be in the form of a solid, liquid, or aqueous solution. Among these, lactic acid, glycolic acid, or derivatives thereof are particularly preferred. These aliphatic oxycarboxylic acids may be used alone or in a mixture of two or more.

[0036] When the polyester resin (A) contains these aliphatic oxycarboxylic acid units, the content thereof is preferably 20 mol % or less, more preferably 10 mol % or less, even more preferably 5 mol % or less, and most preferably 0 mol % (not included), based on 100 mol % of all structural units constituting the polyester resin (A), from the viewpoint of moldability.

[0037] The polyester resin (A) may have an increased melt viscosity by copolymerizing a trifunctional or higher aliphatic polyhydric alcohol, a trifunctional or higher aliphatic polycarboxylic acid or its acid anhydride, or a trifunctional or higher aliphatic polyoxycarboxylic acid component.

[0038] Specific examples of trifunctional aliphatic polyhydric alcohols include trimethylolpropane, glycerin, etc., and specific examples of tetrafunctional aliphatic polyhydric alcohols include pentaerythritol, etc. These may be used alone or in combination of two or more. A specific example of a trifunctional aliphatic polycarboxylic acid or its acid anhydride is propanetricarboxylic acid or its acid anhydride, and a specific example of a tetrafunctional polycarboxylic acid or its acid anhydride is cyclopentanetetracarboxylic acid or its acid anhydride, etc. These may be used alone or in combination of two or more.

[0039] Trifunctional aliphatic oxycarboxylic acids are divided into (i) types having two carboxyl groups and one hydroxyl group in the same molecule, and (ii) types having one carboxyl group and two hydroxyl groups. Either type can be used, but from the viewpoints of moldability, mechanical strength, and the appearance of molded products, types having two carboxyl groups and one hydroxyl group in the same molecule, such as malic acid, are preferred. More specifically, malic acid is preferred. Tetrafunctional aliphatic oxycarboxylic acid components are divided into (i) types having three carboxyl groups and one hydroxyl group in the same molecule, (ii) types having two carboxyl groups and two hydroxyl groups in the same molecule, and (iii) types having three hydroxyl groups and one carboxyl group in the same molecule. Either type can be used, but those having multiple carboxyl groups are preferred. More specifically, examples include citric acid and tartaric acid. These can be used alone or in combination.

[0040] When the polyester resin (A) contains such structural units derived from trifunctional or higher functional components, the content thereof, with all structural units constituting the aliphatic polyester resin (A) being 100 mol %, is generally 0 mol % or more in lower limit, preferably 0.01 mol % or more in upper limit, and generally 5 mol % or less, preferably 2.5 mol % or less in upper limit.

[0041] The method for producing the aliphatic polyester resin (A) according to the present invention can employ a known method for producing polyesters. The polycondensation reaction can be carried out under conventionally adopted conditions, and is not particularly limited. Usually, a method is employed in which the degree of polymerization is further increased by carrying out a reduced pressure operation after the esterification reaction has proceeded.

[0042] When a diol component forming a diol unit and a dicarboxylic acid component forming a dicarboxylic acid unit are reacted during the production of the aliphatic polyester resin (A), the amounts of the diol component and the dicarboxylic acid component used are set so that the aliphatic polyester resin (A) produced has the desired composition. Usually, the diol component and the dicarboxylic acid component react in substantially equimolar amounts, but the diol component is usually used in a 1 to 20 mol % excess over the dicarboxylic acid component because it is distilled off during the esterification reaction.

[0043] When the aliphatic polyester resin (A) contains components (optional components) other than the essential components such as aliphatic hydroxycarboxylic acid units and polyfunctional component units, the corresponding compounds (monomers and oligomers) are reacted so that the aliphatic hydroxycarboxylic acid units and polyfunctional component units have the desired compositions. In this case, there are no limitations on the timing and method of introducing the optional components into the reaction system, and they are optional as long as the aliphatic polyester resin (A) suitable for the present invention can be produced.

[0044] For example, the timing and method of introducing the aliphatic hydroxycarboxylic acid into the reaction system are not particularly limited as long as it is before the polycondensation reaction between the diol component and the dicarboxylic acid component. Examples include (1) a method in which the catalyst is dissolved in an aliphatic hydroxycarboxylic acid solution in advance and mixed, and (2) a method in which the catalyst is introduced into the reaction system and mixed at the same time when the raw materials are charged.

[0045] The timing of introducing the compound that forms the polyfunctional component unit may be such that it is charged simultaneously with other monomers or oligomers at the initial stage of polymerization, or it may be charged after the transesterification reaction and before the start of decompression. However, charging it simultaneously with other monomers or oligomers is preferred from the viewpoint of simplifying the process.

[0046] The aliphatic polyester resin (A) is usually produced in the presence of a catalyst. Any catalyst that can be used in the production of known polyester resins can be selected as the catalyst 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 preferred.

[0047] 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, and tetrabutoxygermanium are preferred in terms of cost and availability, with germanium oxide being particularly preferred.

[0048] Examples of titanium compounds that can be used as catalysts include organic titanium compounds such as tetraalkoxytitanium compounds such as tetrapropyl titanate, tetrabutyl titanate, and tetraphenyl titanate. Among these, tetrapropyl titanate, tetrabutyl titanate, and the like are preferred in terms of price and availability.

[0049] In addition, other catalysts may be used in combination as long as the object of the present invention is not impaired. The catalysts may be used alone or in any combination and ratio of two or more.

[0050] 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, based on the amount of monomer used. If the amount is below the lower limit of this range, the effect of the catalyst may not be exhibited, while if the amount is above the upper limit, the production cost may increase, the resulting polymer may be significantly discolored, or the hydrolysis resistance may decrease.

[0051] The timing of introducing the catalyst is not particularly limited as long as it is before the polycondensation reaction, and it may be introduced when the raw materials are charged or when pressure reduction is started. When an aliphatic oxycarboxylic acid unit is introduced, it is preferably introduced simultaneously with a monomer or oligomer that forms an aliphatic oxycarboxylic acid unit, such as lactic acid or glycolic acid, when the raw materials are charged, or by dissolving the catalyst in an aqueous aliphatic oxycarboxylic acid solution and introducing it. In particular, the method of dissolving the catalyst in an aqueous aliphatic oxycarboxylic acid solution and introducing it is preferred because it increases the polymerization rate.

[0052] The reaction conditions, such as temperature, polymerization time, and pressure, used in producing the aliphatic polyester resin (A) may be any as long as they do not significantly impair the effects of the present invention. The reaction temperature for the esterification reaction and / or transesterification reaction between the dicarboxylic acid component and the diol component is typically 150°C or higher, preferably 180°C or higher, and typically 260°C or lower, preferably 250°C or lower. The reaction atmosphere is typically an inert atmosphere such as nitrogen or argon. The reaction pressure is typically normal pressure to 10 kPa, with normal pressure being preferred. The reaction time is typically 1 hour or higher, and typically 10 hours or shorter, preferably 6 hours or shorter, and more preferably 4 hours or shorter. If the reaction temperature is too high, excessive unsaturated bonds may be generated, resulting in gelation caused by the unsaturated bonds, making it difficult to control the polymerization.

[0053] The pressure for the polycondensation reaction after the esterification reaction and / or transesterification reaction between the dicarboxylic acid component and the diol component is usually 0.01 × 10 3 Pa or more, preferably 0.03 x 10 3 Pa or higher, with an upper limit of 1.4×10 3 Pa or less, preferably 0.4×10 3It is desirable to carry out the reaction under a vacuum of 100 Pa or less. The lower limit of the reaction temperature is usually 150°C or higher, preferably 180°C or higher, and the upper limit is usually 260°C or lower, preferably 250°C or lower. The lower limit of the reaction time is usually 2 hours or higher, and the upper limit is usually 15 hours or lower, preferably 10 hours or lower. If the reaction temperature is too high, excessive generation of unsaturated bonds may cause gelation due to the unsaturated bonds, making it difficult to control the polymerization.

[0054] When producing the aliphatic polyester resin (A), a chain extender such as a carbonate compound or a diisocyanate compound can also be used. In this case, the amount of the chain extender is usually 10 mol% or less, preferably 5 mol% or less, and more preferably 3 mol% or less, as the proportion of carbonate bonds or urethane bonds in the polyester resin (A) when all the structural units constituting the aliphatic polyester resin are 100 mol%. However, the presence of urethane bonds or carbonate bonds in the aliphatic polyester resin (A) may inhibit biodegradability. Therefore, in the present invention, the carbonate bonds are less than 1 mol%, preferably 0.5 mol% or less, more preferably 0.1 mol% or less, and the urethane bonds are 0.55 mol% or less, preferably 0.3 mol% or less, more preferably 0.12 mol% or less, and even more preferably 0.05 mol% or less, relative to all the structural units constituting the aliphatic polyester resin (A). This amount, calculated per 100 parts by mass of the aliphatic polyester resin (A), is 0.9 parts by mass or less, preferably 0.5 parts by mass or less, more preferably 0.2 parts by mass or less, and even more preferably 0.1 parts by mass or less. In particular, if the amount of urethane bonds exceeds the upper limit, decomposition of the urethane bonds may cause problems in the film-forming process, such as smoke and odor from the molten film exiting the die outlet, and film breakage due to foaming may occur in the molten film, making it impossible to stably mold it. The carbonate bond amount and urethane bond amount in the aliphatic polyester resin (A) are 1 H-NMR and 13 It can be calculated from the results of NMR measurements such as C-NMR.

[0055] Specific examples of carbonate compounds as the chain extender include diphenyl carbonate, ditolyl carbonate, bis(chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, ethylene carbonate, diamyl carbonate, dicyclohexyl carbonate, etc. In addition, carbonate compounds composed of the same or different hydroxy compounds derived from hydroxy compounds such as phenols and alcohols can also be used.

[0056] Specific examples of the diisocyanate compound include known diisocyanates such as 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, and tolidine diisocyanate.

[0057] Other chain extenders such as dioxazoline and silicate esters may also be used. Specific examples of silicate esters include tetramethoxysilane, dimethoxydiphenylsilane, dimethoxydimethylsilane, and diphenyldihydroxysilane.

[0058] High molecular weight polyester resins using these chain extenders (coupling agents) can also be produced using conventional techniques. After polycondensation is complete, the chain extender is added to the reaction system in a homogeneous molten state without a solvent, and reacted with the polyester obtained by polycondensation.

[0059] More specifically, a polyester with substantially hydroxyl terminal groups and a weight-average molecular weight (Mw) of 20,000 or more, preferably 40,000 or more, obtained by catalytically reacting a diol component with a dicarboxylic acid component, can be reacted with the above-mentioned chain extender to obtain a higher molecular weight polyester resin. Prepolymers with a weight-average molecular weight of 20,000 or more can be produced with the use of a small amount of chain extender without gel formation during the reaction, even under harsh conditions such as in a molten state, because they are not affected by residual catalyst. Here, the weight-average molecular weight (Mw) of the polyester resin is determined by gel permeation chromatography (GPC) using chloroform as the solvent at 40°C, converted into a monodisperse polystyrene value.

[0060] Therefore, when further increasing the molecular weight of a polyester resin using, for example, the above-mentioned diisocyanate compound as a chain extender, it is preferable to use a prepolymer having a weight-average molecular weight of 20,000 or more, preferably 40,000 or more. If the weight-average molecular weight is less than 20,000, the amount of diisocyanate compound used to increase the molecular weight may increase, resulting in a decrease in heat resistance. Using such a prepolymer, a polyester resin having urethane bonds with a linear structure linked via urethane bonds derived from the diisocyanate compound is produced.

[0061] The pressure during chain extension is usually 0.01 MPa or more and 1 MPa or less, preferably 0.05 MPa or more and 0.5 MPa or less, more preferably 0.07 MPa or more and 0.3 MPa or less, and most preferably normal pressure.

[0062] The lower limit of the reaction temperature during chain extension is usually 100° C. or higher, preferably 150° C. or higher, more preferably 190° C. or higher, and most preferably 200° C. or higher, and the upper limit is usually 250° C. or lower, preferably 240° C. or lower, and more preferably 230° C. or lower. If the reaction temperature is too low, the viscosity will be high, making it difficult to achieve a uniform reaction, and high stirring power will tend to be required. If the reaction temperature is too high, gelation or decomposition of the polyester resin will tend to occur concomitantly.

[0063] The lower limit of the time for chain extension is usually 0.1 minute or more, preferably 1 minute or more, and more preferably 5 minutes or more, and the upper limit is usually 5 hours or less, preferably 1 hour or less, more preferably 30 minutes or less, and most preferably 15 minutes or less. If the time for chain extension is too short, the effect of adding the chain extender tends not to be exerted, and if it is too long, gelation or decomposition of the polyester resin tends to occur concomitantly.

[0064] The molecular weight of the aliphatic polyester resin (A) used in the present invention can be measured by gel permeation chromatography (GPC). The weight average molecular weight (Mw) of the aliphatic polyester resin (A) using monodisperse polystyrene as the standard is usually 10,000 or more and 1,000,000 or less, but is preferably 20,000 or more and 500,000 or less, and more preferably 50,000 or more and 400,000 or less, because this is advantageous in terms of moldability and mechanical strength.

[0065] The melt flow rate (MFR) of the aliphatic polyester resin (A) is measured at 190°C under a load of 2.16 kg according to JIS K7210 (1999), and is usually 0.1 g / 10 min or more and 100 g / 10 min or less, but from the viewpoint of moldability and mechanical strength, it is preferably 50 g / 10 min or less, particularly preferably 30 g / 10 min or less. The MFR of the aliphatic polyester resin (A) can be adjusted by the molecular weight.

[0066] The melting point of the aliphatic polyester resin (A) is preferably 70° C. or higher, more preferably 75° C. or higher, and is preferably 170° C. or lower, more preferably 150° C. or lower, and particularly preferably lower than 130° C. When there are multiple melting points, it is preferable that at least one of the melting points is within the above range. The elastic modulus of the aliphatic polyester resin (A) is preferably 180 to 1000 MPa. If the melting point is outside the above range, moldability will be poor, if the modulus of elasticity is less than 180 MPa, problems will likely occur in moldability, and if the modulus of elasticity exceeds 1000 MPa, the resulting tubular body will tend to be more susceptible to cracking.

[0067] The method for adjusting the melting point and elastic modulus of the aliphatic polyester resin (A) is not particularly limited. For example, the melting point and elastic modulus can be adjusted by selecting the type of copolymerization component of the aliphatic dicarboxylic acid component other than succinic acid, adjusting the copolymerization ratio of each component, or combining these components. As the aliphatic polyester resin (A), commercially available products can be used, such as "BioPBS (registered trademark) FZ71PB," "BioPBS (registered trademark) FZ71PM," "BioPBS (registered trademark) FZ91PB," "BioPBS (registered trademark) FZ91PM," "BioPBS (registered trademark) FD92PB," and "BioPBS (registered trademark) FD92PM," all manufactured by PTTMCC Biochem.

[0068] In the present invention, the aliphatic polyester resin (A) is not limited to one type, and a blend of two or more types of aliphatic polyester resins (A) differing in the types and ratios of constituent units, production methods, physical properties, etc. may be used.

[0069] <Polyhydroxyalkanoate (B)> The polyhydroxyalkanoate (hereinafter sometimes referred to as PHA) (B) used in the present invention is an aliphatic polyester containing repeating units represented by the general 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 main constituent units.

[0070] From the viewpoints of moldability and thermal stability, the polyhydroxyalkanoate (B) used in the present invention preferably contains 80 mol% or more, and more preferably 85 mol% or more, of 3-hydroxybutyrate units as a constituent component. Furthermore, polyhydroxyalkanoates produced by microorganisms are preferred. Specific examples of polyhydroxyalkanoates (B) include poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer resins and poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) copolymer resins. In particular, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer resin, ie, PHBH, is preferred from the viewpoint of molding processability and the physical properties of the resulting molded article.

[0071] In the polyhydroxyalkanoate (B), the ratio of 3-hydroxybutyrate (hereinafter sometimes referred to as 3HB) to the copolymerized comonomer, such as 3-hydroxyhexanoate (hereinafter sometimes referred to as 3HH), i.e., the monomer ratio in the copolymer resin, is preferably 3-hydroxybutyrate / comonomer = 97 / 3 to 80 / 20 (mol % / mol %), and more preferably 95 / 5 to 85 / 15 (mol % / mol %), from the viewpoints of molding processability and molded product quality. If this comonomer ratio is less than 3 mol %, molding may be difficult because the molding temperature and thermal decomposition temperature are close to each other. If the comonomer ratio exceeds 20 mol %, the crystallization of the polyhydroxyalkanoate (B) may be slow, resulting in reduced productivity.

[0072] The ratio of each monomer in the polyhydroxyalkanoate (B) can be measured by gas chromatography as follows. Approximately 20 mg of dried PHA is added to 2 ml of a sulfuric acid / methanol mixture (15 / 85 by mass) and 2 ml of chloroform, sealed, and heated at 100°C for 140 minutes to obtain the methyl ester of the PHA decomposition product. 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 evolution of carbon dioxide gas stops. 4 ml of diisopropyl ether is added and mixed well, and the monomer unit composition of the PHA decomposition product in the supernatant is analyzed by capillary gas chromatography to determine the ratio of each monomer in the copolymer resin.

[0073] The weight-average molecular weight (hereinafter sometimes referred to as Mw) of the polyhydroxyalkanoate (B) used in the present invention can be measured by the above-mentioned gel permeation chromatography (GPC), and the weight-average molecular weight (Mw) using monodisperse polystyrene as the standard substance is usually 200,000 to 2,500,000, but is preferably 250,000 to 2,000,000, more preferably 300,000 to 1,000,000, because this is advantageous in terms of moldability and mechanical strength. If the weight-average molecular weight is less than 200,000, the mechanical properties may be poor, and if it exceeds 2,500,000, molding processing may be difficult.

[0074] The melt flow rate (MFR) of the polyhydroxyalkanoate (B), as measured at 190°C under a load of 2.16 kg according to JIS K7210 (1999), is preferably 1 g / 10 min or more and 100 g / 10 min or less, but from the viewpoints of moldability and mechanical strength, is more preferably 80 g / 10 min or less, and particularly preferably 50 g / 10 min or less. The MFR of the polyhydroxyalkanoate (B) can be adjusted by the molecular weight.

[0075] The melting point of the polyhydroxyalkanoate (B) is preferably 100° C. or higher, more preferably 120° C. or higher, and is preferably 180° C. or lower, more preferably 170° C. or lower, and particularly preferably lower than 160° C. When there are multiple melting points, it is preferable that at least one of the melting points is within the above range.

[0076] Polyhydroxyalkanoate (B) can be produced by, for example, a microorganism such as Alcaligenes eutrophus AC32 strain, which is obtained by introducing a PHA synthase gene derived from Aeromonas caviae into Alcaligenes eutrophus (international deposit under the Budapest Treaty, international depository authority: International Patent Organism Depositary of the National Institute of Advanced Industrial Science and Technology (6-1 Central, 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)).

[0077] Commercially available products can also be used as the polyhydroxyalkanoate (B). Commercially available products of the polyhydroxyalkanoate (B) containing 3-hydroxybutyrate units and 3-hydroxyhexanoate units as main constituent units include "Aonilex (registered trademark) X131N," "Aonilex (registered trademark) X131A," "Aonilex (registered trademark) 151A," "Aonilex (registered trademark) 151C," "PHBH (registered trademark) X331N," "PHBH (registered trademark) X131A," "PHBH (registered trademark) 151A," and "PHBH (registered trademark) 151C," all manufactured by Kaneka Corporation.

[0078] In the present invention, the polyhydroxyalkanoate (B) is not limited to one type, and a blend of two or more types of polyhydroxyalkanoates (B) differing in the type and ratio of constituent units, production method, physical properties, etc. can be used.

[0079] <Inorganic filler (C)> The aliphatic polyester resin composition of the present invention further contains an inorganic filler (C) in addition to the polyester resin (A) and the polyhydroxyalkanoate (B).

[0080] Examples of the inorganic filler (C) used in the present invention include anhydrous silica, mica, talc, titanium oxide, calcium carbonate, diatomaceous earth, allophane, bentonite, potassium titanate, zeolite, sepiolite, smectite, kaolin, kaolinite, glass, limestone, carbon, wollastonite, calcined perlite, silicates such as calcium silicate and sodium silicate, hydroxides such as aluminum oxide, magnesium carbonate and calcium hydroxide, and salts such as ferric carbonate, zinc oxide, iron oxide, aluminum phosphate and barium sulfate, with talc, calcium carbonate and zeolite being preferred.

[0081] Some inorganic fillers, such as calcium carbonate and limestone, have soil conditioner properties. If a tubular body made of an aliphatic polyester resin composition containing a biomass-derived aliphatic polyester resin (A) and a polyhydroxyalkanoate (B) that contains a particularly large amount of these inorganic fillers is dumped into the soil, the inorganic filler (C) will remain after biodegradation and will also function as a soil conditioner, thereby enhancing its significance as a biodegradable resin.

[0082] The inorganic filler (C) can also be classified by its shape, and includes fibrous, spherical, plate-like, and needle-like fillers, with spherical or plate-like fillers being preferred. Examples of spherical fillers include calcium carbonate, spherical silica, spherical glass beads, and graphite. Examples of plate-like fillers include talc, kaolin, mica, clay, sericite, glass flakes, synthetic hydrotalcite, various metal foils, graphite, molybdenum disulfide, tungsten disulfide, boron nitride, plate-like iron oxide, plate-like calcium carbonate, plate-like aluminum hydroxide, and zeolite. From the viewpoints of ease of blending, rigidity, moldability, decomposability, and enhanced deodorizing effect, talc, mica, or clay, calcium carbonate, and zeolite are preferred.

[0083] The particle size of the inorganic filler (C) used in the present invention is preferably 0.5 μm or more, more preferably 0.6 μm or more, even more preferably 0.7 μm or more, and particularly preferably 1.0 μm or more, for ease of handling. On the other hand, the average particle size is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less. Here, the method for measuring the average particle diameter of the inorganic filler (C) is not particularly limited, but a specific example of the measurement method is to determine the specific surface area per 1 g of powder measured using a powder specific surface area measuring device SS-100 (constant pressure air permeability method) manufactured by Shimadzu Corporation, and then calculate the average particle diameter of the filler from the measurement results of the specific surface area measured using the air permeability method in accordance with JIS M8511 using the following formula. Average particle size (μm) = 10,000 × {6 / (specific gravity of filler × specific surface area)}

[0084] The inorganic filler (C) may be used alone or as a mixture of two or more kinds in any combination and ratio.

[0085] Specific examples of talc that can be suitably used as the inorganic filler (C) include Microace manufactured by Nippon Talc Co., Ltd., and MG113 and MG115 manufactured by Fuji Talc Kogyo Co., Ltd. Specific examples of calcium carbonate that can be suitably used as the inorganic filler (C) include Softon 1200 and 2200 manufactured by Bihoku Funka Kogyo Co., Ltd.

[0086] <Composition ratio of aliphatic polyester resin (A), polyhydroxyalkanoate (B), and inorganic filler (C)> The mass ratio of the aliphatic polyester resin (A) to the polyhydroxyalkanoate (B) contained in the aliphatic polyester resin composition of the present invention is preferably aliphatic polyester resin (A) / polyhydroxyalkanoate (B)=40 / 60 to 10 / 90, more preferably 45 / 55 to 15 / 85, and even more preferably 50 / 50 to 20 / 80, from the viewpoints of improving rigidity and ease of molding processability. On the other hand, from the viewpoint of reducing odors felt when used in food packaging, the mass ratio of aliphatic polyester resin (A) / polyhydroxyalkanoate (B) is preferably 50 / 50 to 90 / 10, more preferably 51 / 49 to 85 / 15, and even more preferably 52 / 48 to 80 / 20.

[0087] The content of the inorganic filler (C) in the aliphatic polyester resin composition of the present invention is 5 to 50 mass% of the total of the aliphatic polyester resin (A), the polyhydroxyalkanoate (B), and the inorganic filler (C), preferably 10 to 45 mass%, and more preferably 15 to 40 mass%. If the content of the inorganic filler (C) is less than the above lower limit, the aforementioned effects of incorporating the inorganic filler (C) cannot be fully obtained, and the effects of improving room temperature biodegradability, marine biodegradability, and moldability cannot be obtained. On the other hand, if the content of the inorganic filler (C) is more than the above upper limit, mechanical strength such as impact resistance decreases.

[0088] <Other resins> The aliphatic polyester resin composition of the present invention may contain one or more resins other than the aliphatic polyester resin (A) and the polyhydroxyalkanoate (B), such as synthetic resins such as aromatic polyester resins, polycarbonate, polyamide, polystyrene, polyolefin, acrylic resin, amorphous polyolefin, ABS, AS (acrylonitrile styrene), polycaprolactone, polyvinyl alcohol, and cellulose ester, and biodegradable resins such as polylactic acid and the aliphatic aromatic polyester polybutylene adipate terephthalate (PBAT), within the range that does not impair the effects of the present invention.

[0089] When the aliphatic polyester resin composition of the present invention contains these other resins, in order to effectively obtain the effects of the present invention by including the aliphatic polyester resin (A) and the polyhydroxyalkanoate (B) as resin components, the content of the other resins is preferably 70 parts by mass or less, particularly 50 parts by mass or less, per 100 parts by mass of the total of the aliphatic polyester resin (A), the polyhydroxyalkanoate (B), and the other resins.

[0090] <Other ingredients> The aliphatic polyester resin composition of the present invention may contain, as "other components", various additives such as lubricants, plasticizers, antistatic agents, antioxidants, light stabilizers, UV absorbers, dyes, pigments, hydrolysis inhibitors, crystal nucleating agents, antiblocking agents, light resistance agents, plasticizers, heat stabilizers, flame retardants, release agents, anti-fogging agents, surface wetting improvers, incineration aids, dispersing aids, various surfactants, and slip agents, as well as fine powders of animal or plant substances such as starch, cellulose, paper, wood flour, chitin / chitosan, coconut shell powder, and walnut shell powder, or mixtures thereof. Furthermore, the aliphatic polyester resin composition of the present invention may also contain functional additives such as a freshness-preserving agent and an antibacterial agent. These may be blended in any amount within the range that does not impair the effects of the present invention, and one type may be used alone, or two or more types may be mixed and used.

[0091] In order not to impair the physical properties of the aliphatic polyester resin composition of the present invention, it is usually preferable that the total amount of the components to be mixed is 0.01 mass % or more and 40 mass % or less relative to the total amount of the aliphatic polyester resin composition of the present invention.

[0092] Among the other components, the antifogging agent may be kneaded into the aliphatic polyester resin composition in advance, or may be applied to the surface of the molded article after molding. Specifically, the antifogging agent used is preferably an ester surfactant of a saturated or unsaturated aliphatic carboxylic acid having from 4 to 20 carbon atoms and a polyhydric alcohol.

[0093] Examples of slip agents include unsaturated and saturated fatty acid amides and unsaturated and saturated fatty acid bisamides made from unsaturated and saturated fatty acids having 6 to 30 carbon atoms, with erucic acid amide, oleic acid amide, stearic acid amide, and their bisamides being the most preferred. These can be blended in any amount within the range that does not impair the effects of the present invention, and one type may be used alone, or two or more types may be mixed and used.

[0094] Examples of the anti-blocking agent include saturated fatty acid amides having 6 to 30 carbon atoms, saturated fatty acid bisamides, methylolamide, ethanolamide, natural silica, synthetic silica, synthetic zelite, and talc.

[0095] Specific examples of the light stabilizer include bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate, 2-(3,5-di-t-butyl-4-hydroxyphenyl)-2-n-butyl-bis(2,2,6,6-tetramethyl-4-piperidyl)malonate, 2-(3,5-di-t -butyl-4-hydroxyphenyl)-2-n-butyl-bis(1,2,2,6,6-pentamethyl-4-piperidyl)malonate, 2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butyl-bis(2,2,6,6-tetramethyl-4-piperidyl)malonate, 2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butyl-bis(1,2,2,6,6-pentamethyl-4-piperidyl)malonate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, mixed(2,2,6,6-tetramethyl-4-piperidyl / tridecyl)-1,2,3,4-butanetetracarboxylate, mixed(1,2,2,6,6-pentamethyl-4-piperidyl / tridecyl)-1,2 ,3,4-butanetetracarboxylate, mixed {2,2,6,6-tetramethyl-4-piperidyl / β,β,β',β'-tetramethyl-3,9-[2,4,8,10-tetraoxaspiro[5.5]undecane]diethyl}-1,2,3,4-butanetetracarboxylate, mixed {1,2,2,6,6-pentamethyl-4-piperidyl / β,β,β',β'-tetramethyl-3,9-[2,4,8,10-tetraoxaspiro[5.5]undecane)]diethyl}-1,2,3,4-butanetetracarboxylate, 1,2-bis(3-oxo-2,2,6,6-tetramethyl-4-piperidyl)ethane, 1-(3,5-di-t-butyl-4-hydroxyphenyl)-1,1-bis(2,2,6,6-tetramethyl-4-piperidyloxycarbonyl)pentane, poly[1-oxyethylene(2,2,6,6-tetramethyl-1,4-piperidyl)oxysuccinyl], poly[2-(1,1,4-trimethylbutylimino)-4,6-triazinedicarboxylate] Examples of suitable condensation products include N,N'-bis(3-aminopropyl)ethylenediamine-2,4-bis[N-butyl-N-(2,2,6,6-tetramethyl-4-piperidyl)amino]-6-chloro-1,3,5-triazine condensates and their N-methyl compounds, and polycondensates of succinic acid and 1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine.

[0096] Among these, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate and 2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butyl-bis(1,2,2,6,6-pentamethyl-4-piperidyl)malonate are particularly preferred.

[0097] As the ultraviolet absorber, among benzophenone-based, benzotriazole-based, salicylic acid-based, cyanoacrylate-based, and other ultraviolet absorbers, benzotriazole-based ultraviolet absorbers are preferred, and specific examples thereof include 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole and 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-hexyloxy-phenol.

[0098] Antioxidants include BHT (dibutylhydroxytoluene), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 3,3',3",5,5',5"-hexa-tert-butyl-α,α',α"-(mesitylene-2,4,6-triyl)tri-p-cresol, and octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) Propionate, 1,3,5-tris[(4-tert-butyl-3-hydroxy-2,6-xylyl)methyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, calcium diethyl bis[{3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl}methyl]phosphonate, bis(2,2'-dihydroxyphenyl)methyl hindered phenol antioxidants such as N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl)-4-hydroxyphenyl]propionamide, tridecyl phosphite, diphenyldecyl phosphite, tetrakis(2,4-di-tert-butylphenyl)[1,1-biphenyl]-4,4'-diylbisphosphonate, bis[2,4-bis(1,1-dimethylethyl)- Examples of antioxidants include phosphorus-based antioxidants such as bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, lactone-based antioxidants such as the reaction product of 3-hydroxy-5,7-di-tert-butyl-furan-2-one with xylene, sulfur-based antioxidants such as dilauryl thiodipropionate, distearyl thiodipropionate, and mixtures of two or more of these. Among these, hindered phenol-based antioxidants are preferably used.

[0099] Preferred hindered phenol-based antioxidants include Irganox 3790, Irganox 1330, Irganox 1010, Irganox 1076, Irganox 3114, Irganox 1425WL, Irganox 1098, Irganox HP2225FL, Irganox HP2341, Irgafos XP-30 (all manufactured by BASF), and Sumilizer BBM-S (manufactured by Sumitomo Chemical Co., Ltd.). The most preferred antioxidants are Irganox 1010 (pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]) and Irganox 1330 (3,3',3",5,5',5"-hexa-tert-butyl-α,α',α"-(mesitylene-2,4,6-triyl)tri-p-cresol).

[0100] <Method of producing an aliphatic polyester resin composition> The aliphatic polyester resin composition of the present invention is produced by mixing the aliphatic polyester resin (A), the polyalkanoate (B), and the inorganic filler (C), with other resins and other components that are used as needed.

[0101] This mixing step is carried out by mixing the aliphatic polyester resin (A), polyhydroxyalkanoate (B), and inorganic filler (C) with other resins and other components used as needed in a predetermined ratio simultaneously or in any order using a mixer such as a tumbler, V-type blender, Nauta mixer, Banbury mixer, kneading roll, or extruder, and preferably melt-kneading the mixture.

[0102] The kneader used in the mixing step may be a melt kneader. While there is no limitation on the type of twin-screw extruder or single-screw extruder, a twin-screw extruder is more preferred for the purpose of achieving melt kneading according to the properties of the aliphatic polyester resin (A), polyhydroxyalkanoate (B), and inorganic filler (C) used.

[0103] The temperature during melt-kneading is preferably 120 to 220° C., and more preferably 130 to 160° C. This temperature range makes it possible to shorten the time required for the melting reaction, prevent deterioration of color tone due to resin degradation, and further improve practical physical properties such as impact resistance and moist heat resistance. Furthermore, with regard to the melt-kneading time, from the viewpoint of more reliably avoiding the same resin deterioration as described above, unnecessary lengthening should be avoided, and the time is preferably from 20 seconds to 20 minutes, more preferably from 30 seconds to 15 minutes, and it is preferable to set the melt-kneading temperature and time conditions so as to satisfy this requirement.

[0104] [Molded body] The tubular body of the present invention is obtained by molding the aliphatic polyester resin composition of the present invention. Examples of molding methods include injection molding, extrusion molding, coextrusion molding (film molding by inflation method or T-die method, laminate molding, pipe molding, electric wire / cable molding, molding of profiled materials), heat press molding, blow molding (various blow moldings), thermoforming (vacuum forming, pressure forming), plastic processing, powder molding (rotational molding), and various nonwoven fabric moldings (dry method, adhesive method, entanglement method, spunbond method, etc.). Among these, extrusion molding is preferably used.

[0105] The tubular body of the present invention obtained by molding the aliphatic polyester resin composition of the present invention can also be subjected to various secondary processes for the purpose of imparting surface functions such as chemical functions, electrical functions, magnetic functions, mechanical functions, friction / wear / lubrication functions, optical functions, thermal functions, biocompatibility, etc. Examples of secondary processes include bellows processing, embossing, painting, bonding, printing, metallizing (plating, etc.), machining, and surface treatments (antistatic treatment, corona discharge treatment, plasma treatment, photochromism treatment, physical vapor deposition, chemical vapor deposition, coating, etc.).

[0106] [Application] The tubular body of the present invention can be suitably used for straws, tubes, hoses, cotton swab shafts, film or sheet cylinders, balloon sticks (holding rods), etc., particularly for disposable applications. [Example]

[0107] Specific embodiments of the present invention will be described in more detail below using examples, but the present invention is not limited to the following examples as long as the gist of the invention is not exceeded. Note that the values ​​of various production conditions and evaluation results in the following examples represent preferred upper or lower limit values ​​in the embodiments of the present invention, and preferred ranges may be defined by a combination of the above-mentioned upper or lower limit values ​​and the values ​​in the following examples or values ​​between the examples.

[0108] [Melt flow rate (MFR) measurement of resin used] Measurement was carried out using a melt indexer at 190°C under a load of 2.16 kg in accordance with JIS K7210 (1999). The unit is g / 10 min.

[0109] [Raw materials used] Details of the resins and inorganic fillers used in the examples and comparative examples are as follows. In the following, "PBS" stands for "polybutylene succinate," "PBSA" stands for "polybutylene succinate adipate," "PLA" stands for "polylactic acid," "PHBH" stands for "poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)," and "PBAT" stands for "polybutylene adipate terephthalate."

[0110] <Aliphatic polyester resin (A)> PBS (PTTMC BioChem BioPBS FZ91PM, MFR: 5.0 g / 10 min, melting point: 113°C) PBSA (BioPBS FD92PM manufactured by PTTMC Biochem, succinic acid unit content in total dicarboxylic acid units: 74 mol%, MFR: 5.0 g / 10 min, melting point: 89°C)

[0111] <Polyhydroxyalkanoate (B)> PHBH-1 (PHBH (registered trademark) X131A manufactured by Kaneka Corporation, 3HB / 3HH molar ratio: 94 / 6, MFR: 6 g / 10 min, melting point: 140°C) PHBH-2 (Aonilex (registered trademark) X151A, manufactured by Kaneka Corporation, 3HB / 3HH molar ratio: 89 / 11, MFR: 6 g / 10 min, melting point: 131°C)

[0112] <Polylactic acid> PLA (NatureWorks 4032D, MFR: 3.5g / 10min, melting point: 170℃)

[0113] <Aliphatic / aromatic polyester> PBAT (BASF Ecoflex C1200, MFR: 4g / 10min, melting point: 110℃)

[0114] <Inorganic filler (C)> Talc (MG-115 manufactured by Fuji Talc Industries, average particle size: 14 μm) Talc (Micro Ace K-1, manufactured by Nippon Talc Co., Ltd., average particle size: 8 μm) CaCO3 (Softon 1200, manufactured by Bihoku Funka Kogyo Co., Ltd., average particle size: 2 μm)

[0115] [Evaluation method] The methods for evaluating various physical properties and characteristics in the examples and comparative examples are as follows.

[0116] <Formability evaluation> The moldability when obtaining straws using a tubular circular die was evaluated according to the following criteria. ◯: No surging or cutting defects occurred, and a good sample was obtained. ×: Surging or cutting failure occurred.

[0117] <Piercing test> The tips of 10 straws were cut at a 45° angle using general-purpose scissors. The tips were then manually pierced from 3.5 cm above a 40 μm-thick polyethylene film attached to a cup. The condition was evaluated according to the following criteria. ○: All 10 straws penetrated the polyethylene film without breaking. △: 5 to 9 out of 10 penetrate the polyethylene film. ×: None of the ten pieces penetrated the polyethylene film.

[0118] <Odor test> Ten people evaluated whether they perceived any odor when drinking mineral water through the molded straws. The evaluation criteria are shown below. ◎: Fewer than two people noticed the smell ○: 3 or 4 people noticed the smell ×: Five or more people noticed the smell

[0119] <Elmendorf tear test> The measurement was carried out based on JIS K7128-2 (2007). The higher the tear strength, the better the tear resistance, and thus the more preferable.

[0120] <Soil biodegradation test> The sheets were stored in soil (30% moisture content) collected from a farm in Mie Prefecture for three months at 28±2°C, after which their weight was measured and their biodegradability was evaluated according to the following criteria. The degree of decomposition was calculated using the following formula. Degradation rate (%) = 100 - (sample weight after 3 months / sample weight before test) x 100 ○: Decomposition rate is 90% or more △: Decomposition rate is 30% or more but less than 90% ×: Decomposition rate is less than 30%

[0121] <Biodegradation test in seawater> The sheets were stored in seawater collected from Yokkaichi Port in Yokkaichi City, Mie Prefecture at 28±2°C for 6 months, after which their weight was measured and their biodegradability was evaluated according to the following criteria. The degree of decomposition was calculated using the following formula. Degradation rate (%) = 100 - (sample weight after 6 months / sample weight before test) x 100 ○: Decomposition rate is 50% or more △: Decomposition rate is 10% or more but less than 50% ×: Decomposition rate is less than 10%

[0122] <Marine biodegradability test (ASTM D6691)> The amount of CO2 generated 100 days after the start of the test was measured based on the test method of ASTM D6691, and the biodegradability was calculated using a calculation method in accordance with ASTM D6691. The test was conducted using seawater from the sea near Belgium, the measurement temperature was 30±2°C, and the evaluation sample was 60 mg of powder with an average particle size of 250 μm or less.

[0123] [Examples 1 to 6, Comparative Examples 1 and 2] The raw materials shown in Table 1 were blended in the ratios shown in Table 1, extruded into strands using a twin-screw extruder with a screw diameter of 30 mm at a kneading temperature of 140°C, and pelletized using a pelletizer. The resulting resin pellets were extruded into tubular shapes with a diameter of 7 mm and a wall thickness of 0.2 mm using a tubular circular die to obtain straws, which were then subjected to a puncture test and an odor test. The odor test was conducted only for Examples 1, 3, 4, and 6 and Comparative Examples 1 and 2. The pellets were pressed into sheets 100 μm thick, and biodegradation tests in soil and seawater were carried out. The obtained pellets were then powdered to an average particle size of 250 μm or less, and 60 mg of the powder was used to evaluate the degree of marine biodegradability in accordance with the marine biodegradability test according to ASTM D6691. The results are shown in Table 1. In Table 1, "Talc" refers to "Talc (MG-115 manufactured by Fuji Talc Industries Co., Ltd., average particle size: 14 μm)" in Examples 1 to 3, and to "Talc (Micro Ace K-1 manufactured by Nippon Talc Co., Ltd., average particle size: 8 μm)" in Example 6.

[0124] Comparative Example 3 The raw materials shown in Table 1 were blended in the ratios shown in Table 1 and kneaded at 180°C, and molding and evaluation were carried out in the same manner as in Example 1.

[0125] [Table 1]

[0126] [Examples 7 and 8, Comparative Example 4] The raw materials shown in Table 2 were blended in the proportions shown in Table 2, extruded into strands using a twin-screw extruder with a screw diameter of 30 mm at a mixing temperature of 140°C, and pelletized using a pelletizer. The resulting resin pellets were then molded into a tubular film with a wall thickness of 30 μm using an inflation film molding machine with a screw diameter of 40 mm at a molding temperature of 160°C and a blow ratio of 2.5. This film was subjected to a tear test. The resulting film was also subjected to soil biodegradation tests and seawater biodegradation tests. The results are shown in Table 2. In Table 2, "Talc" refers to "Talc (Microace K-1, manufactured by Nippon Talc Co., Ltd., average particle size: 8 μm)."

[0127] [Table 2]

[0128] From Table 1, it can be seen that the tubular body of the present invention has higher biodegradability at room temperature and excellent biodegradability in seawater compared to molded bodies made from conventional biodegradable resins, and also has excellent moldability when obtaining molded bodies, as well as excellent mechanical properties such as puncture strength. From Table 2, it can be seen that the tubular body of the present invention has high biodegradability at room temperature, excellent biodegradability in seawater, and high tear strength, so it is difficult to tear even when used as a cylindrical body made of film.

Claims

1. An aliphatic polyester resin composition comprising: an aliphatic polyester resin (A) containing, as main structural units, a repeating unit derived from an aliphatic diol and a repeating unit derived from an aliphatic dicarboxylic acid; a polyhydroxyalkanoate (B); and an inorganic filler (C), a mass ratio of the aliphatic polyester-based resin (A) to the polyhydroxyalkanoate (B) is aliphatic polyester-based resin (A) / polyhydroxyalkanoate (B)=90 / 10 to 10 / 90; the polyhydroxyalkanoate (B) is a copolymer containing 3-hydroxybutyrate units and 3-hydroxyhexanoate units as main structural units, the content of the inorganic filler (C) relative to the total amount of the aliphatic polyester-based resin (A), the polyhydroxyalkanoate (B), and the inorganic filler (C) is 5 to 50 mass%; A straw having a tubular body made of an aliphatic polyester resin composition, in which the proportion of repeating units derived from succinic acid among all repeating units derived from dicarboxylic acids contained in the aliphatic polyester resin (A) is 5 mol% or more and 100 mol% or less.

2. An aliphatic polyester-based resin composition comprising: an aliphatic polyester-based resin (A) containing, as main structural units, a repeating unit derived from an aliphatic diol and a repeating unit derived from an aliphatic dicarboxylic acid; a polyhydroxyalkanoate (B); and an inorganic filler (C), a mass ratio of the aliphatic polyester-based resin (A) to the polyhydroxyalkanoate (B) is aliphatic polyester-based resin (A) / polyhydroxyalkanoate (B)=90 / 10 to 10 / 90; the polyhydroxyalkanoate (B) is a copolymer containing 3-hydroxybutyrate units and 3-hydroxyhexanoate units as main structural units, the content of the inorganic filler (C) relative to the total amount of the aliphatic polyester-based resin (A), the polyhydroxyalkanoate (B), and the inorganic filler (C) is 5 to 50 mass%; The cotton swab includes a tubular body made of an aliphatic polyester-based resin composition, in which the proportion of repeating units derived from succinic acid in all repeating units derived from dicarboxylic acids contained in the aliphatic polyester-based resin (A) is 5 mol % or more and 100 mol % or less.

3. An aliphatic polyester-based resin composition comprising: an aliphatic polyester-based resin (A) containing, as main structural units, a repeating unit derived from an aliphatic diol and a repeating unit derived from an aliphatic dicarboxylic acid; a polyhydroxyalkanoate (B); and an inorganic filler (C), a mass ratio of the aliphatic polyester-based resin (A) to the polyhydroxyalkanoate (B) is aliphatic polyester-based resin (A) / polyhydroxyalkanoate (B)=90 / 10 to 10 / 90; the polyhydroxyalkanoate (B) is a copolymer containing 3-hydroxybutyrate units and 3-hydroxyhexanoate units as main structural units, the content of the inorganic filler (C) relative to the total amount of the aliphatic polyester-based resin (A), the polyhydroxyalkanoate (B), and the inorganic filler (C) is 5 to 50 mass%; A balloon stick comprising a tubular body made of an aliphatic polyester resin composition, in which the proportion of repeating units derived from succinic acid among all repeating units derived from dicarboxylic acids contained in the aliphatic polyester resin (A) is 5 mol% or more and 100 mol% or less.

4. The straw according to claim 1, wherein the inorganic filler (C) is one or more selected from the group consisting of anhydrous silica, calcium carbonate, talc, and zeolite.

5. The straw according to claim 1 or 4, wherein the aliphatic diol that provides the repeating units derived from the aliphatic diol is 1,4-butanediol.

6. The cotton swab according to claim 2, wherein the inorganic filler (C) is one or more selected from the group consisting of anhydrous silica, calcium carbonate, talc, and zeolite.

7. The cotton swab according to claim 2 or 6, wherein the aliphatic diol that provides the repeating units derived from the aliphatic diol is 1,4-butanediol.

8. 4. The balloon stick according to claim 3, wherein the inorganic filler (C) is one or more selected from the group consisting of anhydrous silica, calcium carbonate, talc, and zeolite.

9. The balloon stick according to claim 3 or 8, wherein the aliphatic diol that provides the repeating units derived from the aliphatic diol is 1,4-butanediol.

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