WO2020202813A1 - Polyester resin composition, production method therefor, and molded body - Google Patents

Abstract

The present invention pertains to a polyester resin composition that: includes 10%–40% by mass poly (3-hydroxy butyrate) resin (A), 30%-60% by mass of aliphatic aromatic polyester (B), 10%–30% by mass of starch (C), 0.1%–7% by mass of a dispersant (D), and 0.05%–1.0% by mass of a lubricant (E); and does not substantially include inorganic matter. The poly (3-hydroxy butyrate) resin (A) includes a constituent unit indicated by [-CHCH₃-CH₂-CO-O-]. The lubricant (E) includes at least one type selected from the group consisting of aliphatic carboxylic acid metal salts and a fatty acid amide. As a result, a polyester resin composition is provided that can rapidly decompose in nature, does not generate residue such as inorganic matter, and has excellent formability.

Description

Polyester-based resin composition, its manufacturing method and molded product

The present invention relates to a polyester-based resin composition using a biodegradable resin, a method for producing the same, and a molded product.

In recent years, garbage derived from plastic products such as plastic films has become a problem. Amid the long-awaited realization of a recycling-oriented society on a global scale, research and development of resin compositions using biodegradable resins that are decomposed into water and carbon dioxide by the action of microorganisms after use and molded articles made of them are being conducted. It is actively carried out. For example, Patent Document 1 describes a resin composition containing an aliphatic polyester resin, which is a biodegradable resin, silica, and a dispersant.

International Publication No. 2018/012583

However, since the resin composition described in Patent Document 1 contains an inorganic substance (silica), the inorganic substance may remain even if the biodegradable resin is decomposed. Therefore, as the problem of environmental pollution becomes more serious, there is a demand for a resin composition that does not substantially contain an inorganic substance and has moldability equivalent to that of a resin composition having an inorganic substance.

In order to solve the above-mentioned conventional problems, the present invention provides a polyester resin composition which is rapidly decomposed in the natural world, hardly generates residues such as inorganic substances, and has excellent moldability, a method for producing the same, and a molded product. provide.

As a result of diligent studies to solve the above problems, the present inventors have made a polyester resin composition in which a specific component is mixed in a specific ratio, which is excellent in biodegradability and molding processability, and can withstand practical use. We have found that a molded product having an excellent balance of characteristics can be obtained, and have completed the present invention. That is, the present invention includes one or more of the following aspects.

The present invention relates to a polyester-based resin composition containing a poly (3-hydroxybutyrate) -based resin (A), an aliphatic aromatic polyester (B), a starch (C), a dispersant (D), and a lubricant (E). , Poly (3-hydroxybutyrate) -based resin (A) contains a structural unit represented by the following general formula (1), and the lubricant (E) comprises a metal salt of an aliphatic carboxylic acid and a fatty acid amide. When one or more selected from the group is contained and the polyester-based resin composition is 100% by weight, the poly (3-hydroxybutyrate) -based resin (A) is 10% by weight or more and 40% by weight or less, and an aliphatic fragrance. Group polyester (B) is 30% by weight or more and 60% by weight or less, starch (C) is 10% by weight or more and 30% by weight or less, dispersant (D) is 0.1% by weight or more and 7.0% by weight or less, and lubricant. The present invention relates to a polyester-based resin composition, which comprises 0.05% by weight or more and 1.0% by weight or less of (E) and substantially does not contain an inorganic substance.

In the polyester-based resin composition of one or more embodiments of the present invention, the poly (3-hydroxybutyrate) -based resin (A) contains a poly (3-hydroxy) containing a structural unit represented by the following general formula (2). Butyrate-co-3-hydroxyhexanoate) is preferably included.

(However, in the general formula (2), R represents a C ₃ H ₇ group linear.)

In one or more embodiments of the present invention, the poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) contains 83 mol% or more and 91 mol% or less of 3-hydroxybutyrate units, and 3-hydroxy. Hexanoate units may be contained in an amount of 9 mol% or more and 17 mol% or less.

In one or more embodiments of the present invention, the poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) exceeds 3-hydroxybutyrate units by 91 mol% to 99 mol%, and 3-hydroxy. Hexanoate units may be contained in an amount of 1 mol% or more and less than 9 mol%.

In one or more embodiments of the present invention, the aliphatic aromatic polyester (B) preferably contains polybutylene adipate terephthalate (PBAT).

In one or more embodiments of the present invention, it is preferable that the lubricant (E) contains two or more selected from the group consisting of metal salts of aliphatic carboxylic acids and fatty acid amides.

In one or more embodiments of the present invention, the lubricant (E) preferably contains a fatty acid amide.

In one or more embodiments of the present invention, the polyester-based resin composition preferably further contains a crystal nucleating agent (F).

In one or more embodiments of the present invention, the dispersant (D) preferably contains a glycerin ester compound.

The present invention relates to a molded product containing the polyester-based resin composition in one or more embodiments.

The present invention comprises, in one or more embodiments, the method for producing the polyester-based resin composition, the step of preparing a mixture (X) containing an aliphatic aromatic polyester (B) and starch (C). A step of dry-blending a poly (3-hydroxybutyrate) resin (A), a dispersant (D) and a lubricant (E) to obtain a mixture (Y), and melting the mixture (X) and the mixture (Y). The present invention relates to a method for producing a polyester resin composition, which comprises a step of kneading.

According to the present invention, it is possible to provide a polyester-based resin composition which can be rapidly decomposed in nature, hardly generates residues such as inorganic substances, and has excellent moldability, and a molded product containing the same. ..
Further, according to the production method of the present invention, it is possible to obtain a polyester resin composition which can be rapidly decomposed in the natural world, hardly generates residues such as inorganic substances, and has excellent moldability.

The embodiments of the present invention will be described in detail below, but the present invention is not limited to the following embodiments.

In one or more embodiments of the present invention, the polyester-based resin composition comprises a poly (3-hydroxybutyrate) -based resin (A), an aliphatic aromatic polyester (B), a starch (C), and a dispersant (D). And the lubricant (E) as an essential ingredient.

<Poly (3-hydroxybutyrate) resin (A)>
The poly (3-hydroxybutyrate) resin (A) contains a structural unit represented by the following general formula (1).

The poly (3-hydroxybutyrate) -based resin (A) may be a poly (3-hydroxybutyrate) having only 3-hydroxybutyrate as a repeating unit, or 3-hydroxybutyrate and other hydroxy. It may be a copolymer with alkanoate. Further, the poly (3-hydroxybutyrate) resin may be a mixture of a homopolymer and one or more kinds of copolymers, or may be a mixture of two or more kinds of copolymers.

The poly (3-hydroxybutyrate) -based resin (A) is not particularly limited, but specifically, poly (3-hydroxybutyrate) and poly (3-hydroxybutyrate-co-3-hydroxyhexano) are used. Ate), poly (3-hydroxybutyrate-co-3-hydroxyvariate), poly (3-hydroxybutyrate-co-4-hydroxybutyrate), poly (3-hydroxybutyrate-co-3-hydroxy) Octanoate), poly (3-hydroxybutyrate-co-3-hydroxyoctadecanoate) and the like. Among them, poly (3-hydroxybutyrate), poly (3-hydroxybutyrate-co-3-hydroxyhexanoate), and poly (3-hydroxybutyrate-co-) are easy to produce industrially. 3-Hydroxyvariate) and poly (3-hydroxybutyrate-co-4-hydroxybutyrate) are preferably selected from the group consisting of one or more.

Furthermore, by changing the composition ratio of each monomer unit, the melting point and crystallinity can be changed, and the physical properties such as Young's ratio and heat resistance can be changed, and the physical properties between polypropylene and polyethylene can be imparted. The poly (3-hydroxybutyrate) resin (A) is represented by the following general formula (2) from the viewpoint of being possible, industrially easy to produce, and physically useful. It is particularly preferable to use poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) having a structural unit.

(However, in the general formula (2), R represents a C ₃ H ₇ group linear)

In particular, among the poly (3-hydroxybutyrate) -based resins (A) having the property of being easily thermally decomposed at a temperature of 180 ° C. or higher, poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) has a melting point. It is also preferable from the viewpoint that it is possible to reduce the amount of the material and to perform the molding process at a low temperature.

The composition ratio of the monomer unit in the poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) is the 3-hydroxybutyrate unit and the 3-hydroxyhexanoate unit from the viewpoint of the balance between flexibility and strength. When the total of is 100 mol%, it is preferable that the 3-hydroxybutyrate unit is 75 mol% or more and 99 mol% or less, and the 3-hydroxyhexanoate unit is 1 mol% or more and 25 mol% or less. It is more preferable that the 3-hydroxybutyrate unit is 80 mol% or more and 97 mol% or less, and the 3-hydroxyhexanoate unit is 3 mol% or more and 20 mol% or less. In poly (3-hydroxybutyrate-co-3-hydroxyhexanoate), when the 3-hydroxybutyrate unit is 99 mol% or less, flexibility can be imparted to the resin. Further, in poly (3-hydroxybutyrate-co-3-hydroxyhexanoate), when the 3-hydroxybutyrate unit is 75 mol% or more, the resin has an appropriate hardness.

The poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) is a total of 100 mol% of 3-hydroxybutyrate units and 3-hydroxyhexanoate units from the viewpoint of increasing the tear strength of the molded product. , The 3-hydroxybutyrate unit is preferably 83 mol% or more and 91 mol% or less, and the 3-hydroxyhexanoate unit is preferably 9 mol% or more and 17 mol% or less, and more preferably 3-hydroxybutyrate. The rate unit is 85 mol% or more and 91 mol% or less, and the 3-hydroxyhexanoate unit is 9 mol% or more and 15 mol% or less.

The poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) is a 3-hydroxybutyrate unit and 3-hydroxybutyrate unit from the viewpoint that a molded product having excellent shape retention such as being less likely to lose its shape can be easily obtained. When the total of hydroxyhexanoate units is 100 mol%, 3-hydroxybutyrate units are contained in an amount of more than 91 mol% and 99 mol% or less, and 3-hydroxyhexanoate units are contained in an amount of 1 mol% or more and less than 9 mol%. More preferably, it contains 92 mol% or more and 98 mol% or less of 3-hydroxybutyrate units, and 2 mol% or more and 8 mol% or less of 3-hydroxyhexanoate units.

As the poly (3-hydroxybutyrate-co-3-hydroxyhexanoate), for example, a commercially available product such as "Kaneka Biodegradable Polymer PHBH" (registered trademark) manufactured by Kaneka Corporation can be used.

<Alphatic aromatic polyester (B)>
The aliphatic aromatic polyester (B) contains an aliphatic diol as a diol component, and contains an aliphatic dicarboxylic acid and an aromatic dicarboxylic acid as a dicarboxylic acid component. The aliphatic diol of the aliphatic aromatic polyester (B) is not particularly limited, and examples thereof include ethylene diol and butane diol. The aliphatic dicarboxylic acid is not particularly limited, and includes, for example, adipic acid and sebacin. Examples thereof include acids, azelaic acids, and succinic acids, and the aromatic dicarboxylic acid is not particularly limited. For example, a benzene ring-containing dicarboxylic acid such as terephthalic acid, a polyarophatic ring-containing dicarboxylic acid such as naphthalenedicarboxylic acid, and a flange. Examples thereof include a furan ring-containing dicarboxylic acid such as a carboxylic acid.

The aliphatic aromatic polyester (B) is not particularly limited, and specific examples thereof include polybutylene adipate terephthalate (PBAT), polybutylene sebacate terephthalate, polybutylene azelate terephthalate, and polybutylene succinate terephthalate. In particular, polybutylene adipate terephthalate can be preferably used because it is excellent in physical properties such as tensile elongation at break and moldability.

The polybutylene adipate terephthalate (PBAT) refers to a random copolymer of 1,4-butanediol, adipic acid and terephthalic acid, and among them, it is described in JP-A-10-508640. (A) Mainly adipic acid or an ester-forming derivative thereof or a mixture thereof 35 mol% or more and 95 mol% or less, terephthalic acid or an ester-forming derivative thereof or a mixture thereof 5 mol% or more and 65 mol% or less (individual) The total of mol% of the monomers in the above is 100 mol%), and the mixture containing (b) butanediol (where the molar ratio of (a) and (b) is 0.4: 1 to PBAT or the like obtained by the reaction of 1.5: 1) is preferable. As the PBAT, for example, a commercially available product such as "Ecoflex" (registered trademark) manufactured by BASF may be used.

<Starch (C)>
Starch (C) is mainly composed of carbohydrates, which are aggregates of amylose and amylopectin, and is stored in seeds, rhizomes, etc. as a nutrient storage substance for plants, and generally has a shape such as starch derived from plants. Therefore, those that can be obtained as those containing water and ash can be used. Specific examples of the starch include corn starch, wheat starch starch, rice starch, soramame starch, green bean starch, small bean starch, horse belly starch, sweet potato starch, and tapioca starch.

Starch (C) may be a starch derivative. Starch derivative means modified starch or functional starch. As the starch derivative, starch in which the free OH group is at least partially substituted is preferably used, for example, starch modified with an ether group and / or an ester group, hydrophobic starch, hydrophilic starch, hydroxy. Examples thereof include propyl starch and carboxymethyl starch.

The above-mentioned starch and starch derivative can be used individually by 1 type, or can be used in combination of 2 or more type.

<Dispersant (D)>
The dispersant (D) can be used to control the dispersibility of each component in order to improve the processability and properties of the resin composition and the molded product made from the resin composition. As the dispersant (D), for example, an ester compound can be used, and more specifically, a glycerin ester compound, an adipic acid ester compound, a polyether ester compound, a phthalate ester compound, and an isosorbide. Examples thereof include ester compounds and polycaprolactone compounds. Of these, glycerin ester compounds such as glycerin diacet monolaurate, glycerin diacet monocaprelate, and glycerin diacet monodecanoate; diethylhexyl adipate, dioctyl adipate, because they have excellent affinity for resin components and are difficult to bleed. Adiponic acid ester compounds such as diisononyl adipate; polyether ester compounds such as polyethylene glycol dibenzoate, polyethylene glycol dicaprelate, and polyethylene glycol diisostearate are preferable, and those containing a large amount of biomass-derived components are the entire composition. It is particularly preferable because it can increase the degree of biomass of ester. Examples of the dispersant containing a large amount of biomass-derived components include commercially available products such as "Rikemar" (registered trademark) PL series of RIKEN Vitamin Co., Ltd. and Polysorb series of ROQUETTE.

As the dispersant (D), a glycerin ester compound is particularly preferable because it is excellent in cost and versatility and has a high degree of biomass. As the glycerin ester compound, any monoester, diester, or triester of glycerin can be used, but the triester of glycerin is preferable from the viewpoint of promoting crystallization. Among the glycerin triesters, the glycerin diacet monoester is particularly preferable. As specific examples of the glycerin diacet monoester, glycerin diacet monolaurate, glycerin diacet monooleate, glycerin diacet monostearate, glycerin diacet monocaprelate, glycerin diacet monodecanoate and the like can be preferably used.

The above-mentioned dispersant can be used alone or in combination of two or more.

<Glidant (E)>
The lubricant (E) contains one or more selected from the group consisting of metal salts of aliphatic carboxylic acids and fatty acid amides. By using such a lubricant (E), it is possible to improve the processability and characteristics of the molded product, particularly the mouth opening property of the bag-shaped molded product, without using an inorganic substance such as silica. In addition, the lubricant (E) may have an effect of suppressing friction between the polyester resin composition or its molded product and the apparatus or the like.

The metal salt of the aliphatic carboxylic acid is not particularly limited as long as it is a metal salt of the aliphatic carboxylic acid used as a known lubricant. For example, a metal salt of a higher fatty acid having 12 or more carbon atoms can be used. Examples of higher fatty acids having 12 or more carbon atoms include lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, and behenic acid. Examples of the metal salt include metal salts such as sodium, calcium, magnesium, aluminum, zinc, and barium. Specific examples thereof include metal salts of stearic acid such as sodium stearate, calcium steerate phosphate, magnesium stearate and zinc stearate, and metal salts of behenic acid such as sodium behenate and calcium behenate. In such a respect, a metal salt of stearic acid can be preferably used.

The fatty acid amide may be any amide composed of a fatty acid and an amine, and one having a long-chain aliphatic group and an amide group in the molecule can be used. For example, saturated / unsaturated monoamides, substituted amides, saturated / unsaturated bisamides, methylolamides, ethanolamides, esteramides, aromatic bisamides, substituted ureas and the like can be mentioned. Specific examples of the fatty acid amide include oleic acid amide, erucic acid amide, bechenic acid amide, stearic acid amide, palmitic acid amide, N-stearyl behenic acid amide, N-stearyl erucic acid amide, and ethylene bissteer acid amide. , Ethylenebisoleic acid amide, ethylenebiserucic acid amide, ethylenebislauric acid amide, ethylenebiscapric acid amide, p-phenylene bisstearic acid amide, polycondensate of ethylenediamine, stearic acid and sebacic acid and the like. Of these, it is particularly preferable to use erucic acid amide. By using the erucic acid amide, the friction between the polyester resin composition or the molded product thereof and the apparatus or the like can be further suppressed, and the mouth opening property of the film molded product can be further improved.

As the lubricant (E), one of the above-mentioned lubricants may be used alone, or two or more of them may be used in combination. It is preferable to use a fatty acid amide from the viewpoint that the friction between the polyester resin composition or the molded product thereof and the apparatus can be further suppressed and the mouth opening property of the film molded product is further improved, and erucic acid is preferable. It is more preferable to use an amide.

When two or more kinds of lubricants are used in combination, it is preferable to use a lubricant having a function of suppressing friction between resins as one of them, and behenic acid amide can be preferably used as such a lubricant.

<Crystal Nucleating Agent (F)>
In one or more embodiments of the present invention, the polyester resin composition preferably further contains a crystal nucleating agent (F). This makes it possible to promote the crystallization of the poly (3-hydroxybutyrate) resin (A) contained in the polyester resin composition.

As the crystal nucleating agent (F), a cellulosic compound, a sorbitol-based compound, or the like can be used, but it is preferable to use a sorbitol-based compound (sugar alcohol) because it is particularly effective as a crystal nucleating agent. Among them, pentaerythritol is particularly preferable. Pentaerythritol is a white crystalline organic compound having a melting point of 260.5 ° C. Pentaerythritol is classified as a sugar alcohol, but it is not derived from natural products and can be synthesized by condensing acetaldehyde and formaldehyde in a basic environment.

The pentaerythritol is generally not particularly limited as long as it is generally available, and a reagent product or an industrial product can be used. Examples of the reagent product include Wako Pure Chemical Industries, Ltd., Sigma Aldrich, Tokyo Chemical Industry Co., Ltd. and Merck, and if it is an industrial product, Koei Chemical Industry Co., Ltd. (trade name: Pentalit) and Toyo Chemicals Co., Ltd. products, but are not limited to these.

Some of the generally available reagent products and industrial products contain oligomers such as dipentaerythritol and tripentaerythritol, which are produced by dehydration condensation of pentaerythritol. The above oligomer has no effect on the crystallization of the poly (3-hydroxybutyrate) resin (A), but does not inhibit the crystallization effect of pentaerythritol. Therefore, the pentaerythritol used in the present invention may contain an oligomer.

<Polyester resin composition>
In one or more embodiments of the present invention, the polyester-based resin composition contains 10% by weight or more and 40% by weight of the poly (3-hydroxybutyrate) -based resin (A) when the polyester-based resin composition is 100% by weight. % Or less, aliphatic aromatic polyester (B) 30% by weight or more and 60% by weight or less, starch (C) 10% by weight or more and 30% by weight or less, dispersant (D) 0.1% by weight or more 7.0 It contains 0.05% by weight or more and 1.0% by weight or less of the lubricant (E), and substantially does not contain inorganic substances. In one or more embodiments of the present invention, "substantially free of inorganic substances" means that the content of inorganic substances is less than 1% by weight when the polyester resin composition is 100% by weight. , It is preferable not to add inorganic substances intentionally unless they are contained as impurities.

A molded product such as a film obtained by molding the polyester-based resin composition by containing 10% by weight or more and 40% by weight or less of the poly (3-hydroxybutyrate) -based resin (A) in the polyester-based resin composition. Appropriate elasticity can be imparted to. Preferably, the poly (3-hydroxybutyrate) resin (A) is contained in an amount of 15% by weight or more and 35% by weight or less.

When the polyester-based resin composition contains 30% by weight or more and 60% by weight or less of the aliphatic aromatic polyester (B), the flexibility of the molded product such as a film obtained by molding the polyester-based resin composition is appropriate. Can be given. Preferably, the aliphatic aromatic polyester (B) is contained in an amount of 35% by weight or more and 55% by weight or less.

When the polyester resin composition contains starch (C) in an amount of 10% by weight or more and 30% by weight or less, the tear strength of a molded product such as a film obtained by molding the polyester resin composition can be improved. .. Preferably, the starch (C) is contained in an amount of 15% by weight or more and 30% by weight or less.

When the polyester resin composition contains the dispersant (D) in an amount of 0.1% by weight or more and 7.0% by weight or less, the tear strength of a molded product such as a film obtained by molding the polyester resin composition can be increased. Can be improved. Preferably, the dispersant (D) is contained in an amount of 0.4% by weight or more and 6.0% by weight or less.

In the polyester-based resin composition, the poly (3-hydroxybutyrate) -based resin (A) is poly (3-hydroxybutyrate-co-3-hydroxyhexanoate), and the 3-hydroxybutyrate unit is 91. When it contains mol% or less, it is preferable to contain the dispersant (D) in an amount of 1.0% by weight or more and 7.0% by weight or less, preferably 2.0% by weight, from the viewpoint of further improving the tensile properties and tear strength of the molded product. It is more preferable to contain more than 6.0% by weight.

In the polyester-based resin composition, the poly (3-hydroxybutyrate) -based resin (A) is poly (3-hydroxybutyrate-co-3-hydroxyhexanoate), and the 3-hydroxybutyrate unit is 91. When it is contained in an amount of more than mol%, it is preferable to contain the dispersant (D) in an amount of 0.1% by weight or more and 6.0% by weight or less, preferably 0.2% by weight, from the viewpoint of further improving the tensile properties and tear strength of the molded product. It is more preferable to contain% or more and 2.0% by weight or less, and further preferably 0.4% by weight or more and 1.0% by weight or less.

When the polyester resin composition contains the lubricant (E) in an amount of 0.05% by weight or more and 1.0% by weight or less, the molding processability is excellent, and when the polyester resin composition is molded into a film or bag shape. In addition, the films do not adhere to each other, and the opening of the bag is improved. Preferably, the lubricant (E) is contained in an amount of 0.10% by weight or more and 0.70% by weight or less. Further, when the content of the lubricant (E) is 1.0% by weight or less, the bleed-out of the lubricant can be suppressed, and as a result, the printability on the surface of the molded product is improved. In particular, the use of erucic acid amide as the lubricant (E) enhances the above-mentioned effects. Further, as the lubricant (E), it is preferable to use another fatty acid amide together with the erucic acid amide, and it is particularly preferable to use a behenic acid amide in combination.

The polyester-based resin composition is not particularly limited, but when the polyester-based resin composition is 100% by weight, crystal nuclei from the viewpoint of promoting the crystallization of the poly (3-hydroxybutyrate) -based resin (A). The agent (F) is preferably contained in an amount of 0.05% by weight or more and 2.0% by weight or less, and particularly preferably 0.1% by weight or more and 1.0% by weight or less.

In the polyester resin composition, it is preferable to use a glycerin ester compound as the dispersant (D) and the fatty acid amide (E) as the lubricant (E), as the poly (3-hydroxybutyrate) resin (A). Poly (3-hydroxybutyrate-co-3-hydroxyhexanoate), polybutylene adipate terephthalate as the aliphatic aromatic polyester (B), a glycerin ester compound as the dispersant (D), and a lubricant (E). It is more preferable to use an ester amide, or an ester amide and a bechenic acid amide. In the polyester-based resin composition, poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) as the poly (3-hydroxybutyrate) -based resin (A) is used as the aliphatic aromatic polyester (B). Polybutylene adipate terephthalate, glycerin ester compound as dispersant (D), erucic acid amide as lubricant (E), or erucic acid amide and behenic acid amide, and pentaerythritol (F) as crystal nucleating agent (F). It is more preferable to include.

By using the polyester-based resin composition of the above combination, the film forming processability and mouth opening property are improved, and the tensile strength, tensile strength, tensile elongation at break and the like when the film is formed into a molded product are further improved. be able to. Further, even if it does not substantially contain an inorganic substance, it can have the same processability of a molded product such as a film or a bag as when it contains an inorganic substance.

The polyester resin composition may further contain other additives as long as the effects of the present invention are not impaired. Other additives include pigments, colorants such as dyes, odor absorbers such as activated carbon and zeolite, fragrances such as vanillin and dextrin, antioxidants, antioxidants, weather resistance improvers, UV absorbers, and water repellents. Examples include agents and antibacterial agents. These other additives may contain only one type, or may contain two or more types. The content of these additives is not particularly limited as long as the total amount of the additives is 1% by weight or less, and can be appropriately set by those skilled in the art according to the purpose of use.

<Manufacturing method of polyester resin composition>
The resin composition of the present invention comprises a poly (3-hydroxybutyrate) resin (A), an aliphatic aromatic polyester (B), a starch (C), a dispersant (D) and a lubricant (E), and if necessary. Accordingly, the crystal nucleating agent (F) and other additives can be produced by kneading by a general kneading method. For example, the above components are added and melt-kneaded using an extruder, a kneader, a Banbury mixer, a roll, or the like to prepare a resin composition, which is extruded into a strand shape and then cut to form a columnar or elliptical columnar shape. , Spherical, cubic, rectangular parallelepiped and other particle-shaped resin compositions can be obtained. Further, before melt-kneading, each component may be mixed in a state where it is not melted, and then melt-kneaded.

In one or more embodiments of the present invention, the polyester-based resin composition is not particularly limited, but is a step of preparing a mixture (X) containing an aliphatic aromatic polyester (B) and starch (C), and a poly (3). -A step of dry-blending a (hydroxybutyrate) resin (A), a dispersant (D) and a lubricant (E) to obtain a mixture (Y), and a step of melt-kneading the mixture (X) and the mixture (Y). It is preferable to manufacture in.

As the mixture (X), pellets prepared by melt-kneading the aliphatic aromatic polyester (B) and the starch (C) can usually be used. As the mixture (X) containing the aliphatic aromatic polyester (B) and the starch (C), a commercially available product may be used.

On the other hand, the poly (3-hydroxybutyrate) resin (A), the dispersant (D) and the lubricant (E) can be dry-blended without being melted, so that the number of times of melt-kneading can be reduced and the resin composition can be reduced. It is possible to suppress a decrease in the molecular weight of a substance and thermal decomposition. Further, when the crystal nucleating agent (F) is used, it is preferable to dry-blend it with the poly (3-hydroxybutyrate) resin (A) to prepare a mixture, similarly to the dispersant (D) and the lubricant (E).

As a method of melt-kneading the mixture (X) and the mixture (Y), the mixture (X) and the mixture (Y) may be simultaneously put into an extruder and melt-kneaded, or the mixture (X) and the mixture (Y) may be melt-kneaded. A part of the mixture (Y) may be charged into the extruder at the same time, and then the rest of the mixture (Y) may be charged into the extruder in a plurality of times using a side feeder or the like for melt kneading, or the mixture (X) may be extruded. The mixture may be charged into the machine, and then the entire amount of the mixture (Y) may be charged into the extruder or the like in a plurality of times using a side feeder or the like for melt-kneading. The extruder is not particularly limited, and may be a single-screw extruder or a twin-screw extruder, but a twin-screw extruder is preferable from the viewpoint of versatility and dispersibility. Further, the melt kneading is preferably performed by setting the cylinder temperature to 180 ° C. or lower from the viewpoint of suppressing thermal decomposition of the poly (3-hydroxybutyrate) resin (A). The number of rotations during melt-kneading is not particularly limited, but for example, from the viewpoint of suppressing thermal decomposition and allowing melt-kneading, it is preferably 50 rpm or more and 200 rpm or less, and more preferably 50 rpm or more and 150 rpm or less.

<Molded body>
Since the polyester resin composition of one or more embodiments of the present invention has excellent biodegradability, agriculture, fishery, forestry, gardening, medicine, sanitary products, food industry, clothing, non-clothing, packaging , Automotive, building materials, and other fields, such as garbage bags, agricultural multi-films, forestry smoked sheets, binding tapes including flat yarns, planted root wrap films, diaper back sheets, packaging. It can be used as a molded body molded into a shape suitable for applications such as a sheet for use, a shopping bag, a drain bag, and other compost bags. Among them, a film-shaped or bag-shaped molded product using the polyester-based resin composition of one or more embodiments of the present invention is preferable. By using the resin composition of one or more embodiments of the present invention, it is possible to impart the same tear strength as when the resin composition containing an inorganic substance is used, even if the resin composition containing the inorganic substance is substantially not contained. In particular, by using a predetermined lubricant (E) at a predetermined content, adhesion between the films is suppressed, and a molded product having improved mouth opening can be obtained.

As a method for producing a molded product, a general molding method can be used, and examples thereof include a blow molding method, an inflation molding method, an injection molding method, and an extrusion molding method. In particular, an inflation molding method is preferable as a method for obtaining a film-shaped or bag-shaped molded product in which the resin composition of the present invention can be preferably used, and a single-layer film or a single-layer film or a single-layer film using the polyester-based resin composition of the present invention is used. It can be manufactured as a multilayer film.

Inflation molding is a film molding method in which molten resin is extruded into a tube shape from an extruder with a cylindrical die attached to the tip, and immediately after that, gas is blown into the tube to inflate it into a balloon shape to form a film. It means that. The method of inflation molding is not particularly limited, but for example, it can be carried out as a single-layer or multilayer film using a general inflation molding machine used when molding a thermoplastic resin into a film. In the case of a single-layer film, a general inflation molding machine means a machine in which a cylindrical die is attached to one single-screw extruder, and in the case of a multilayer film, a plurality of machines are used according to the type of resin used. A type in which molten resin can be poured into one cylindrical die from the extruder of the above, and each resin can be laminated in the die. The single-screw extruder is not particularly limited in screw shape as long as it melt-kneads the charged raw material resin and obtains a constant discharge while maintaining a desired temperature, but the one provided with a mixing element has kneadability. It is preferable from the viewpoint of. Further, the structure of the cylindrical die is not particularly limited, but among them, the spiral mandrel die is preferable because the generation of welds is small and the thickness uniformity can be easily obtained. The rotation speed of the screw during melt-kneading is not particularly limited, but for example, from the viewpoint of melting the resin, it is preferably 5 rpm or more and 100 rpm or less, and more preferably 5 rpm or more and 50 rpm or less.

The molding temperature in inflation molding is not particularly limited as long as the poly (3-hydroxybutyrate) resin (A), the aliphatic aromatic polyester (B) and the like can be appropriately melted, but is 135. It is preferably ° C. or higher and 180 ° C. or lower. The molding temperature referred to here refers to the resin temperature from the extruder to the time of ejection from the die. The resin temperature can generally be measured by, for example, a thermometer installed in an adapter. If the temperature is lower than 135 ° C., unmelted resin may be generated and fish eyes may be generated in a molded product such as a film, resulting in poor appearance. On the other hand, when the temperature is higher than 180 ° C., the poly (3-hydroxybutyrate) resin (A) is liable to be thermally deteriorated, resulting in poor appearance as a burnt resin, deterioration of balloon stability, and molding film machinery. There is a risk of degrading the characteristics.

The take-up speed in inflation molding is determined by the film thickness, width, and resin discharge amount, but can be adjusted within the range in which balloon stability can be maintained. Generally, it is preferably 1 m / min or more and 100 m / min or less.

In inflation molding, the air ring sprayed from the outside of the balloon is used to solidify the discharged molten resin and stabilize the balloon. The air ring spraying structure preferably used is a slit type in which a plurality of annular slits for blowing air are provided, and the stabilization of the balloon is promoted by the chamber between the slits.

When the molded product is a film, the film thickness is preferably 5 μm or more and 100 μm or less, and particularly preferably 10 μm or more and 70 μm or less. The film may be tubular.

When the molded product is a laminated film, one of the surface layer and the inner layer may be composed of the polyester resin composition of the present invention, and a plurality of two or more layers may be composed of the polyester resin composition of the present invention. It may be composed of.

When the molded product is a film, it is preferable that both tensile properties and tear properties are compatible. It is preferable to have a tensile elastic modulus, a tensile breaking strength, a tensile elongation at breaking (rate), and a tear strength in a well-balanced manner. Specifically, the tensile elastic modulus in the resin flow direction (MD direction) during film molding is preferably 300 MPa or more and 1200 MPa or less, particularly preferably 300 MPa or more and 1000 MPa or less, and 90 degrees with respect to the resin flow direction during film molding. The tensile elastic modulus in the direction (TD direction) is preferably 300 MPa or more and 1000 MPa or less, and particularly preferably 300 MPa or more and 900 MPa or less. The tensile breaking strength is preferably 20 MPa or more in the MD direction, particularly preferably 25 MPa or more, particularly preferably 15 MPa or more in the TD direction, and particularly preferably 20 MPa or more. The tensile elongation at break (rate) is preferably 150% or more in the MD direction, particularly preferably 200% or more, particularly preferably 150% or more in the TD direction, and particularly preferably 200% or more. The tear strength is preferably 5.0 N / mm or more in the MD direction, particularly preferably 10 N / mm or more, particularly preferably 5.0 N / mm or more in the TD direction, and particularly preferably 10 N / mm or more. By having these characteristics in a well-balanced manner within the above range, a molded product having good molding processability and mouth opening property can be obtained.

Examples and comparative examples are shown below to explain the present invention more specifically, but the present invention is not limited to these examples.

(Ingredients used)
(1) Poly (3-hydroxybutyrate) resin (A)
(A-1)
The 3-hydroxyhexanoate (3HH) composition was 11.2 mol% and the 3-hydroxybutyrate (3HB) composition was 88, which was obtained according to the method described in International Publication No. 2013/147139 (Production Example 1). Poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB3HH) with a weight average molecular weight of 580,000 mol% and measured by GPC.
(A-2)
3 Produced using the KNK-005 strain (see Example 1 of JP-A-2008-29218) instead of the KNK-631 strain in the method described in International Publication No. 2013/147139 (Production Example 1). Poly (3-hydroxy) having a -hydroxyhexanoate (3HH) composition of 5.4 mol%, a 3-hydroxybutyrate (3HB) composition of 94.6 mol%, and a weight average molecular weight of 620,000 as measured by GPC. Butyrate-co-3-hydroxyhexanoate) (P3HB3HH)
(2) Mixture (X) containing aliphatic aromatic polyester (B) and starch (C)
Aliphatic aromatic polyester containing starch consisting of polybutylene adipate terephthalate (PBAT) and potato-derived starch (GF106 / 02 Biotec, PBAT / starch = 66/34 (weight ratio), pelletized)
(3) Dispersant (D)
Glycerin diacet monolaurate: manufactured by Riken Vitamin Co., Ltd., product name "Rikemar PL012"
(4) Lubricants (E)
E-1: Erucic acid amide, manufactured by Nippon Fine Chemical Co., Ltd., product name "Neutron-S"
E-2: Behenic acid amide, manufactured by Nippon Fine Chemical Co., Ltd., product name "BNT-22H"
(5) Crystal nucleating agent (F)
Pentaerythritol: manufactured by Nippon Synthetic Chemistry Co., Ltd., product name "Neurizer P"
(6) Silica Wet silica, manufactured by Toso Silica, product name "Nipsil LP"

The measurement / evaluation method used in Examples and Comparative Examples will be described.

(Film thickness)
The thickness in the resin flow direction (MD direction) at the time of film molding was calculated by measuring a length of 400 mm with a thickness gauge at intervals of 50 mm and arithmetically averaging. The direction of 90 degrees (TD direction) with respect to the resin flow direction at the time of film molding was calculated by measuring the film width of 400 mm with a thickness gauge at intervals of 50 mm and performing an arithmetic mean.

(Tear strength)
Measured in MD direction and TD direction by a light load tear degree tester (manufactured by Kumagai Riki Kogyo Co., Ltd .: NO.2037 special specification machine) having a function and structure conforming to the standard Elmendorf tear tester specified in JIS P 8116. The value obtained was divided by the thickness of the film to obtain the Ermendorf tear strength of the film sample.

(Tensile test)
After storing the multipurpose test piece in an atmosphere of 23 ° C. and 50% humidity for 1 week, a tensile test was performed using EZ-LX (load cell 1 kN) manufactured by Shimadzu Corporation, and a tensile elastic modulus was determined. The tensile breaking strength and the tensile breaking elongation (rate) were measured.

(Inflation molding workability evaluation)
While keeping the screw rotation speed at 10 rpm, increase the film tensile speed at intervals of 5.0 m / min to 2.0 m / min, and measure the film width when the tubular film passes through the first pinch roll where it is folded. The maximum film tensile speed at which the fluctuation of the film width was less than 10 mm was determined and evaluated according to the following four-step criteria. That is, the higher the speed at which the fluctuation of the film width is less than 10 mm, the higher the molding processability, which is an important index for reducing the film molding cost.
4: 11 m / min or more 3: 7.0 m / min or more and less than 11 m / min 2: 5.0 m / min or more and less than 7.0 m / min 1: 5.0 m / min

(Evaluation of mouth opening)
When the tubular film obtained by inflation molding is molded into a bag (especially a gusset bag with a gusset on the side), it is required to be folded by the first pinch roll and then reopened in the same process (mouth opening). Be done. If it cannot be opened in the same process, it is necessary to open the film in another process and insert a gusset after producing the tubular film, which leads to an increase in processing cost. Mouth opening was evaluated according to the following. Whether or not the film immediately after inflation molding at a resin temperature of 150 ° C. and a film tensile speed of 7 m / min was cut out and opened was evaluated according to the following four-step criteria.
4: Easy to open with your finger.
3: Open with your finger.
2: It cannot be opened with a finger, but it can be opened with a tape (mending tape, manufactured by 3M).
1: It cannot be opened even with tape.

<Example 1>
The poly (3-hydroxybutyrate) resin (A), lubricant (E), and crystal nucleating agent (F) were added to a 75 L Henschel mixer at the blending ratios shown in Table 1, and the mixer jacket temperature was set to 20 ° C. While cooling below, the mixture was stirred at 300 rpm for 3 minutes for dry blending. Next, the dispersant (D) was put into a Henschel mixer being stirred, and further stirred at 300 rpm for 3 minutes for dry blending. A twin-screw extruder (TEX44 /) having a diameter of 44 mm so that the obtained mixture and the aliphatic aromatic polyester containing a starch containing the aliphatic aromatic polyester (B) and the starch (C) have a blending ratio shown in Table 1. Separately supplied to the same hopper (manufactured by Japan Steel Works, Ltd.), melt-kneaded under the conditions of a rotation speed of 90 rpm and an extruder cylinder temperature of 140 ° C to 160 ° C, and passed through a water tank filled with water at 25 ° C to pass the strands. The polyester-based resin composition pellet 1 was obtained by solidifying and cutting with a pelletizer.
The obtained polyester-based resin composition pellet 1 is subjected to a screw rotation speed of 10 rpm, a temperature of 150 ° C., by an inflation molding machine (manufactured by Hokushin Sangyo Co., Ltd.) having a single-screw extruder and a cylindrical die (die diameter 100 mm, die clearance 1 mm). Molding was performed under the conditions of a film tensile speed of 7.0 m / min and a folding width of 400 mm to obtain a tubular film having a thickness of 28 μm in the MD direction and a thickness of 26 μm in the TD direction.

<Example 2>
Polyester-based resin composition pellets 2 were obtained in the same manner as in Example 1 except that the compounding ratio of each component was as shown in Table 1 below. Inflation was carried out using the polyester resin composition pellet 2 in the same manner as in Example 1 to prepare a tubular film having a thickness of 26 μm in the MD direction and a thickness of 27 μm in the TD direction.

<Example 3>
Polyester-based resin composition pellets 3 were obtained in the same manner as in Example 1 except that the compounding ratio of each component was as shown in Table 1 below. Inflation was carried out using the polyester resin composition pellet 3 in the same manner as in Example 1 to prepare a tubular film having a thickness of 25 μm in the MD direction and a thickness of 26 μm in the TD direction.

<Example 4>
Polyester-based resin composition pellets 4 were obtained in the same manner as in Example 1 except that the compounding ratio of each component was as shown in Table 1 below. Inflation was carried out using the polyester resin composition pellet 4 in the same manner as in Example 1 to prepare a tubular film having a thickness of 26 μm in the MD direction and a thickness of 31 μm in the TD direction.

<Example 5>
Polyester-based resin composition pellets 5 were obtained in the same manner as in Example 1 except that the compounding ratio of each component was as shown in Table 1 below. Inflation was carried out using the polyester resin composition pellet 5 in the same manner as in Example 1 to prepare a tubular film having a thickness of 28 μm in the MD direction and a thickness of 28 μm in the TD direction.

<Comparative example 1>
Polyester-based resin composition pellets 6 were obtained in the same manner as in Example 1 except that the compounding ratio of each component was as shown in Table 1 below. Inflation was carried out using the polyester resin composition pellet 6 in the same manner as in Example 1 to prepare a tubular film having a thickness of 25 μm in the MD direction and a thickness of 25 μm in the TD direction.

<Comparative example 2>
Polyester-based resin composition pellets 7 were obtained in the same manner as in Example 1 except that the compounding ratio of each component was as shown in Table 1 below. Inflation was carried out using the polyester resin composition pellet 7 in the same manner as in Example 1 to prepare a tubular film having a thickness of 34 μm in the MD direction and a thickness of 32 μm in the TD direction.

<Reference example 1>
Polyester-based resin composition pellets 9 were obtained in the same manner as in Example 1 except that the compounding ratio of each component was as shown in Table 1 below. Inflation was carried out using the polyester resin composition pellet 9 in the same manner as in Example 1 to prepare a tubular film having a thickness of 27 μm in the MD direction and a thickness of 28 μm in the TD direction.

The films obtained in Examples 1 to 5, Comparative Examples 1 and 2, and Reference Example 1 were evaluated for molding processability, mouth opening property, tear strength, and tensile test. The evaluation results are shown in Table 1 below.

As can be seen from the results in Table 1 above, the films of Examples 1 to 3 are almost the same as the films of Reference Example 1 having silica in tear strength and tensile properties even if they do not contain silica. Further, Examples 4 to 5 have excellent tensile properties as compared with Reference Example 1, and in particular, Example 5 has almost the same tear strength as the film of Reference Example 1. The films described in these examples were also excellent in biodegradability and had a good balance of characteristics.

Comparing Example 1 and Example 2, the molding processability of Example 2 was improved as compared with that of Example 1. It is presumed that this is because the amount of the aliphatic aromatic polyester (B) in Example 2 is larger than that in Example 1. Comparing Example 2 and Example 3, the mouth opening property of Example 3 was improved as compared with that of Example 2. It is presumed that this is because the amount of erucic acid amide, which is a lubricant, was increased in Example 3 as compared with Example 2. From the comparison of Examples 1 to 3, it can be seen that the mouth opening property is improved as the blending amount of the erucic acid amide, which is a lubricant, is increased.

Reference Example 1 which does not contain a lubricant but contains silica does not have a bad mouth opening property, but Comparative Example 1 which does not contain a lubricant and silica has a bad mouth opening property. In the present application, the problem of poor mouth opening that occurs when the polyester resin composition does not contain silica because no inorganic substances remain is selected from the group consisting of metal salts of aliphatic carboxylic acids and fatty acid amides. The solution is to include a predetermined amount of one or more specific lubricants. Specifically, in Reference Example 1, the silica content is 4% by weight, whereas one or more specific lubricants selected from the group consisting of metal salts of aliphatic carboxylic acids and fatty acid amides are used. In Examples 1 to 5, even if the content of the lubricant is reduced to 1% by weight or less, the mouth opening property can be maintained at almost the same level or higher.

Example 4 and Example 5 have excellent tensile properties as compared with Comparative Example 1 and Reference Example 1. Further, by appropriately adjusting the blending amount of the poly (3-hydroxybutyrate) resin (A) as compared with Comparative Example 2, the tensile properties and the tear strength can be well compatible with each other.

Compared with Comparative Example 1 and Reference Example 1, molding workability was improved in Examples 2 to 5. It is presumed that this is because the friction between the resins, the resin composition or the molded product and the machine could be reduced by containing the lubricant (E).

Claims (11)

1. In a polyester resin composition containing a poly (3-hydroxybutyrate) resin (A), an aliphatic aromatic polyester (B), a starch (C), a dispersant (D) and a lubricant (E),
   The poly (3-hydroxybutyrate) resin (A) contains a structural unit represented by the following general formula (1).
   The lubricant (E) contains one or more selected from the group consisting of metal salts of aliphatic carboxylic acids and fatty acid amides.
   When the polyester-based resin composition is 100% by weight, the poly (3-hydroxybutyrate) -based resin (A) is 10% by weight or more and 40% by weight or less, and the aliphatic aromatic polyester (B) is 30% by weight or more. 60% by weight or less, starch (C) 10% by weight or more and 30% by weight or less, dispersant (D) 0.1% by weight or more and 7.0% by weight or less, and lubricant (E) 0.05% by weight or more. A polyester-based resin composition containing 1.0% by weight or less and substantially free of inorganic substances.
   

   
2. Claimed that the poly (3-hydroxybutyrate) -based resin (A) contains a poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) containing a structural unit represented by the following general formula (2). Item 2. The polyester-based resin composition according to Item 1.
   

   

   (However, in the general formula (2), R represents a C ₃ H ₇ group linear.)
3. The poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) contains 83 mol% or more and 91 mol% or less of 3-hydroxybutyrate units, and 9 mol% or more and 17 mol% or more of 3-hydroxyhexanoate units. The polyester-based resin composition according to claim 2, which comprises mol% or less.
4. The poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) contains 91 mol% or more and 99 mol% or less of 3-hydroxybutyrate units, and 1 mol% or more and 9 of 3-hydroxyhexanoate units. The polyester-based resin composition according to claim 2, which contains less than mol%.
5. The polyester-based resin composition according to any one of claims 1 to 4, wherein the aliphatic aromatic polyester (B) contains polybutylene adipate terephthalate (PBAT).
6. The polyester-based resin composition according to any one of claims 1 to 5, wherein the lubricant (E) contains two or more kinds selected from the group consisting of a metal salt of an aliphatic carboxylic acid and a fatty acid amide.
7. The polyester-based resin composition according to any one of claims 1 to 6, wherein the lubricant (E) contains a fatty acid amide.
8. The polyester-based resin composition according to any one of claims 1 to 7, further comprising a crystal nucleating agent (F).
9. The polyester resin composition according to any one of claims 1 to 8, wherein the dispersant (D) is a glycerin ester compound.
10. A molded product containing the polyester resin composition according to any one of claims 1 to 9.
11. The method for producing a polyester resin composition according to any one of claims 1 to 9.
    A step of preparing a mixture (X) containing an aliphatic aromatic polyester (B) and a starch (C), and
    A step of dry-blending a poly (3-hydroxybutyrate) resin (A), a dispersant (D) and a lubricant (E) to obtain a mixture (Y), and
    A method for producing a polyester resin composition, which comprises a step of melt-kneading the mixture (X) and the mixture (Y).