Biodegradable resin composition and application of the same

Abstract

To provide a biodegradable resin composition having excellent transparency, flexibility and elasticity.SOLUTION: A resin composition that contains biodegradable resin (A) containing hard biodegradable resin and an epoxy compound (B) having a plurality of epoxy groups, and in which the ratio of the hard biodegradable resin is 90 mass% or more in the biodegradable resin (A) is prepared. The hard biodegradable resin may be polylactic acid-based resin. The epoxy compound (B) may be a bifunctional epoxy compound such as a glycidyl ether compound expressed by the following formula (1) (in the formula, A denotes an alkylene group having a carbon number 2 or more, n denotes an integer of 1 or more, R1 and R2 denote independently a hydrogen atom or a methyl group). The resin composition may further contain plasticizer (C) such as ester-based plasticizer. The haze of the resin composition may be 30% or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a biodegradable resin composition having excellent transparency, flexibility and stretchability, and uses thereof. [Background technology]

[0002] There is a strong demand for efforts to realize a "low-carbon society" by reducing greenhouse gas emissions and an environmentally friendly "resource-circulating society," and the spread of new materials called "bioplastics" is accelerating in order to realize these societies.

[0003] Among these, polylactic acid is used as a plant-derived, biodegradable resin, but it is a hard resin and lacks flexibility for use as a film, which has made it difficult to create a film made primarily of polylactic acid.

[0004] To solve this problem, a known method is to add an additive (plasticizer) to the resin to increase its flexibility, thereby imparting flexibility suitable for film formation.

[0005] Japanese Patent Laid-Open Publication No. 2011-52149 (Patent Document 1) discloses a polylactic acid resin composition composed of polylactic acid, a plasticizer for plasticizing the polylactic acid, and a polymer having a thickening effect.

[0006] Japanese Patent Application Laid-Open Publication No. 2015-193750 (Patent Document 2) discloses a resin composition containing a hard biodegradable resin such as a polylactic acid-based resin, a soft biodegradable resin, a plasticizer, and at least one compound selected from the group consisting of a fatty acid amide compound, an aliphatic monoepoxy compound, and an aliphatic monocarboxylic acid compound. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-52149 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-193750 Summary of the Invention [Problem to be solved by the invention]

[0008] However, as with the resin compositions of Patent Documents 1 and 2, simply imparting flexibility to a resin using a plasticizer limits the range of products that can be manufactured, and this is not applicable to films that require flexibility and stretchability. In particular, no resin compositions with stretchability are known among those made from inexpensive, conventional, hard biodegradable resins that are already mass-produced, such as polylactic acid. Furthermore, combining multiple resins or increasing the number of additives to achieve flexibility, as in Patent Document 2, reduces the transparency of the film, limiting its uses.

[0009] Therefore, an object of the present invention is to provide a biodegradable resin composition having excellent flexibility and stretchability, and uses thereof.

[0010] Another object of the present invention is to provide a biodegradable resin composition having excellent transparency, flexibility and stretchability, and uses thereof.

[0011] A further object of the present invention is to provide a biodegradable resin composition that is excellent in handleability and moldability, and uses thereof. [Means for solving the problem]

[0012] As a result of extensive research to solve the above problems, the present inventors have found that the transparency, flexibility, and stretchability of a biodegradable resin composition can be improved by combining a biodegradable resin containing 90% by mass or more of a rigid biodegradable resin with an epoxy compound having multiple epoxy groups, and have completed the present invention.

[0013] That is, the present invention includes the following aspects.

[0014] Aspect [1]: A resin composition comprising a biodegradable resin (A) containing a hard biodegradable resin and an epoxy compound (B) having a plurality of epoxy groups, wherein the proportion of the hard biodegradable resin in the biodegradable resin (A) is 90 mass% or more.

[0015] Aspect [2]: The resin composition of aspect [1], wherein the hard biodegradable resin is a polylactic acid-based resin.

[0016] Aspect [3]: The resin composition according to aspect [1] or [2], wherein the epoxy compound (B) is a bifunctional epoxy compound.

[0017] Aspect [4]: ​​The bifunctional epoxy compound is represented by the following formula (1):

[0018] [ka]

[0019] (In the formula, A represents an alkylene group having 2 or more carbon atoms, n represents an integer of 1 or more, and R 1 and R 2 each independently represents a hydrogen atom or a methyl group. The resin composition according to the above aspect [3], wherein the glycidyl ether compound is represented by the formula:

[0020] Aspect [5]: The resin composition according to any one of Aspects [1] to [4], wherein the proportion of the epoxy compound (B) is 0.5 to 20 parts by mass per 100 parts by mass of the biodegradable resin (A).

[0021] Aspect [6]: The resin composition according to any one of Aspects [1] to [5], further comprising a plasticizer (C).

[0022] Aspect [7]: The resin composition of aspect [6], wherein the plasticizer (C) is an ester-based plasticizer.

[0023] Aspect [8]: The resin composition according to aspect [6] or [7], wherein the proportion of the plasticizer (C) is 50 to 1000 parts by mass per 100 parts by mass of the epoxy compound (B).

[0024] Aspect [9]: The resin composition according to any one of Aspects [1] to [8], wherein the haze is 30% or less.

[0025] Aspect

[10] : The resin composition according to any one of Aspects [1] to [9], wherein the melt flow rate at a temperature of 190° C. and a load of 2.16 kgf is 5 g / 10 min or more.

[0026] Aspect

[11] : A molded article formed from the resin composition according to any one of Aspects [1] to

[10] .

[0027] Aspect

[12] : The molded article of aspect

[11] , which is a film or sheet.

[0028] Aspect

[13] : A method for producing a molded article according to aspect

[11] or

[12] , comprising heating and melting a resin composition comprising a biodegradable resin (A) containing a hard biodegradable resin and an epoxy compound (B) having a plurality of epoxy groups, to form the molded article.

[0029] Aspect

[14] : A method for improving at least one of the properties of transparency, stretchability, and flexibility of a resin composition comprising a biodegradable resin (A) containing a rigid biodegradable resin and an epoxy compound (B) having a plurality of epoxy groups, by making the proportion of the rigid biodegradable resin in the biodegradable resin (A) 90 mass% or more.

[0030] In this specification and claims, the number of carbon atoms in a substituent is represented by C1, C6, C 10 For example, "C1 alkyl group" means an alkyl group with 1 carbon atom, and "C 6-10 The term "aryl group" refers to an aryl group having 6 to 10 carbon atoms.

[0031] In this specification and claims, 2-10 "Alkanoic acid" means that the total number of carbon atoms in the alkanoic acid, including the number of carbon atoms in the carboxyl group, is 2 to 10. 2-10The term "alkanedicarboxylic acid" also means that the total number of carbon atoms in the alkanedicarboxylic acid, including the number of carbon atoms in the carboxyl group, is 2 to 10.

[0032] Furthermore, in this specification and claims, when a numerical range is indicated using "X to Y," it means that both ends of the range are included.

[0033] Furthermore, in this specification and claims, the terms "carboxylic acid component," "dicarboxylic acid component," and "hydroxycarboxylic acid component" are used to mean not only carboxylic acids, dicarboxylic acids, and hydroxycarboxylic acids, but also their reactive derivatives (lower alkyl esters, acid anhydrides, or acid halides). [Effects of the Invention]

[0034] The resin composition of the present invention combines a biodegradable resin (A) containing 90% or more by mass of a hard biodegradable resin with an epoxy compound (B) having multiple epoxy groups, thereby improving flexibility and stretchability, as well as transparency. In particular, the use of an inexpensive hard biodegradable resin such as polylactic acid makes it highly economical. Furthermore, the resin composition has excellent thermoplasticity, excellent fluidity, and suppressed bleed-out of additives, resulting in excellent handleability and moldability. DETAILED DESCRIPTION OF THE INVENTION

[0035] The resin composition of the present invention combines a biodegradable resin (A) containing 90% by mass or more of a hard biodegradable resin with an epoxy compound (B) having multiple epoxy groups. Therefore, despite being composed primarily of a hard biodegradable resin, the resin composition can improve flexibility without impairing transparency, and can also achieve thermoplasticity and stretchability.

[0036] [Biodegradable resin (A)] In the resin composition of the present invention, the biodegradable resin (A) contains a hard biodegradable resin as a main component.

[0037] (Hard biodegradable resin) The hard biodegradable resin may be any resin that is conventionally known as a hard biodegradable resin, and may be, for example, a resin with a flexural modulus of elasticity of 1000 MPa or more.

[0038] In this specification and claims, the flexural modulus of the biodegradable resin can be measured in accordance with ISO 178.

[0039] Hard biodegradable resins are made from C-type compounds such as glycolic acid, lactic acid, and butyric acid. 2-4 The hard biodegradable resin may be a biodegradable resin containing, as a polymerization component, a hydroxycarboxylic acid or a hydroxypolycarboxylic acid such as malic acid or tartaric acid. Examples of hard biodegradable resins include polyglycolic acid resins, polylactic acid resins, and polyhydroxybutyric acid resins. These hard biodegradable resins can be used alone or in combination of two or more. They may also be alloy resins combining two or more hard biodegradable resins of different types (or polymerization compositions), but a single type of resin is preferred from the viewpoint of improving transparency. Among these, polylactic acid resins are preferred from the viewpoints of storage stability and versatility. Furthermore, polylactic acid resins, typified by polylactic acid, are versatile and hard, and therefore can effectively realize the effects of the present invention.

[0040] The polylactic acid resin may be a resin (polymer) containing a lactic acid component as a polymerization component. The lactic acid component may be lactic acid (2-hydroxypropanoic acid or 2-hydroxypropionic acid) or a reactive derivative of lactic acid.

[0041] Lactic acid may be an optical isomer (D-form, L-form) or a racemic form (DL-form), but it is preferable to include the L-form (L-lactic acid) in terms of mechanical properties and the like.

[0042] When lactic acid contains an L-isomer, the proportion of the L-isomer in the lactic acid is preferably 10 mol % or more, more preferably 50 mol % or more, even more preferably 70 mol % or more, and most preferably 90 mol % or more.

[0043] When the lactic acid is a combination of L- and D-forms (D-lactic acid), the molar ratio of the L- and D-forms (L- / D-form) may be 99.9 / 0.1 to 10 / 90, for example, 99.5 / 0.5 to 50 / 50, preferably 99 / 1 to 70 / 30, even more preferably 98 / 2 to 80 / 20, even more preferably 97 / 3 to 90 / 10, and most preferably 96 / 4 to 93 / 7.

[0044] Reactive derivatives of lactic acid include lactide (lactic acid dimer), acid anhydride, methyl ester, and other C 1-3 Examples thereof include alkyl esters, acid halides such as acid chlorides, and the like.

[0045] These lactic acid components can be used alone or in combination of two or more. Among these lactic acid components, a lactic acid component containing L-lactic acid [(S)-2-hydroxypropanoic acid] or a reactive derivative thereof is preferred, and a combination of L-lactic acid and D-lactic acid [(R)-2-hydroxypropanoic acid] is particularly preferred.

[0046] The polylactic acid resin is preferably a polymer having a lactic acid component as the main polymerization component, and may be a homopolymer of a lactic acid component (e.g., poly D-lactic acid, poly L-lactic acid, poly D,L-lactic acid, etc.) or a copolymer of a lactic acid component and a copolymer component.

[0047] Examples of copolymerizable components copolymerizable with the lactic acid component include diols, dicarboxylic acid components, hydroxycarboxylic acid components, and lactones.

[0048] The diol is not particularly limited and may be any of aliphatic diols, alicyclic diols, and aromatic diols, but aliphatic diols are preferred from the viewpoint of biodegradability, etc. Examples of aliphatic diols include C 1 diols such as ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, 1,3-butanediol, neopentyl glycol, hexanediol, and octamethylene glycol. 2-10 Aliphatic diols, etc. These diols can be used alone or in combination of two or more.

[0049] Of these diols, C 2-8 Aliphatic diols are preferred, and C 11 diols such as ethylene glycol, 1,4-butanediol, and neopentyl glycol are preferred. 2-6 Alkanediols are particularly preferred.

[0050] The dicarboxylic acid component is not particularly limited and may be any of an aliphatic dicarboxylic acid component, an alicyclic dicarboxylic acid component, and an aromatic dicarboxylic acid component, but from the viewpoint of biodegradability and the like, an aliphatic dicarboxylic acid component is preferred.

[0051] The aliphatic dicarboxylic acid component may be an aliphatic dicarboxylic acid or a reactive derivative of an aliphatic dicarboxylic acid. Examples of the aliphatic dicarboxylic acid include C 12 acid, such as oxalic acid, succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid. 2-10 Examples of reactive derivatives of aliphatic dicarboxylic acids include C anhydrides, methyl esters, etc. 1-3 Examples of the dicarboxylic acid component include alkyl esters, acid halides such as acid chlorides, etc. These dicarboxylic acid components can be used alone or in combination of two or more.

[0052] Of these dicarboxylic acid components, C 2-8 Aliphatic dicarboxylic acids or their reactive derivatives are preferred, and C carboxylic acids such as oxalic acid, succinic acid, and adipic acid are preferred. 2-6 Alkanedicarboxylic acids or reactive derivatives thereof are particularly preferred.

[0053] The hydroxycarboxylic acid component may be any of a hydroxyaliphatic carboxylic acid component, a hydroxyalicyclic carboxylic acid component, and a hydroxyaromatic carboxylic acid component, but from the viewpoint of biodegradability and the like, a hydroxyaliphatic carboxylic acid component is preferred.

[0054] The hydroxyaliphatic carboxylic acid component may be a hydroxyaliphatic carboxylic acid or a reactive derivative of a hydroxyaliphatic carboxylic acid.

[0055] Hydroxyaliphatic carboxylic acids include glycolic acid, 3-hydroxypropanoic acid (3HP), 2-hydroxybutyric acid (2-hydroxybutanoic acid), 3-hydroxybutyric acid (3HB), 4-hydroxybutyric acid (4HB), 3-hydroxy-3-methyl-butyric acid, 2-hydroxyvaleric acid (2-hydroxypentanoic acid), 3-hydroxyvaleric acid (3HV), 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 2-hydroxy-2-methyl-valeric acid, 3-hydroxyhexanoic acid, 6-hydroxyheptanoic acid, 3-hydroxyheptanoic acid, 7-hydroxyheptanoic acid, 3-hydroxyoctanoic acid, 8-hydroxyoctanoic acid, 3-hydroxynananoic acid, 9-hydroxynananoic acid, 3-hydroxydecanoic acid, and 10-hydroxydecanoic acid. 1-6 Hydroxy C optionally having an alkyl group 2-15 Alkanoic acids are included.

[0056] Reactive derivatives of hydroxyaliphatic carboxylic acids include C anhydrides, methyl esters, etc. 1-3 Examples include alkyl esters, acid halides such as acid chlorides, and lactones corresponding to hydroxyaliphatic carboxylic acids.

[0057] Lactones include glycolide, di-C such as β-propiolactone, β-dimethylpropiolactone, γ-butyrolactone, γ-dimethylbutyrolactone, δ-valerolactone, and ε-caprolactone. 1-6 C optionally having an alkyl group 3-15 These lactones can be used alone or in combination of two or more. Among these lactones, C 3-10 Lactones are preferred, and C hydroxy groups such as glycolide, propiolactone, and caprolactone are preferred. 3-8 Lactones are particularly preferred.

[0058] These hydroxycarboxylic acid components can be used alone or in combination of two or more.

[0059] Among these hydroxycarboxylic acid components, hydroxy C 2-10Alkanoic acids or reactive derivatives thereof are preferred, and hydroxy C 2-8 Alkanoic acids or their reactive derivatives are more preferred, and hydroxy C such as glycolic acid and 3-hydroxypropanoic acid. 2-6 Alkanoic acids or reactive derivatives thereof are more preferred.

[0060] These copolymerization components can be used alone or in combination of two or more. Among these copolymerization components, C ethylene glycol and the like are preferred. 2-4 C such as alkanediols and adipic acid 2-6 Alkanedicarboxylic acid components, hydroxy C such as glycolic acid 2-4 Alkanoic acid components, C such as glycolide and caprolactone 4-6 Lactone is preferred. The copolymerization component may be any copolymerization component other than the 3-hydroxybutyric acid component.

[0061] In a polylactic acid resin, the proportion of the lactic acid component as a monomer may be the maximum proportion of all constituent monomers, for example, 50 mol % or more (e.g., about 50 to 99.5 mol %) of all constituent monomers, preferably 70 mol % or more (e.g., about 70 to 99 mol %), more preferably 80 mol % or more (e.g., about 80 to 98 mol %), even more preferably 90 mol % or more, and most preferably 95 mol % or more. The polylactic acid resin may be a resin consisting only of a lactic acid component. If the proportion of the lactic acid component is too low, the biodegradability of the resin composition may be reduced.

[0062] The polylactic acid resin may be an alloy resin made by combining two or more polylactic acid resins of different types (or polymerization compositions), but from the viewpoint of transparency, a single type of polylactic acid resin is preferred.

[0063] The polylactic acid resin may account for 50% by mass or more of the hard biodegradable resin, preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and most preferably 100% by mass.

[0064] The melt flow rate (MFR) of the rigid biodegradable resin (particularly polylactic acid-based resin) is, for example, 1 to 30 g / 10 min, preferably 2 to 20 g / 10 min, further preferably 2.5 to 15 g / 10 min, even more preferably 3 to 10 g / 10 min, and most preferably 3.5 to 7 g / 10 min, under conditions of a temperature of 190°C and a load of 2.16 kgf. If the MFR is too small, the moldability of the resin composition may be reduced, and conversely, if it is too large, the mechanical properties of the resin composition may be reduced.

[0065] The weight average molecular weight of the hard biodegradable resin (particularly, polylactic acid resin) can be selected from the range of 1,000 to 1,000,000, for example, 5,000 to 1,000,000, preferably 10,000 to 800,000, further preferably 20,000 to 700,000, even more preferably 30,000 to 600,000, and most preferably 50,000 to 500,000.

[0066] In this specification and claims, the weight average molecular weight of the resin and resin composition can be measured by GPC in terms of standard polystyrene.

[0067] The glass transition temperature (Tg) of the rigid biodegradable resin (particularly, polylactic acid-based resin) is, for example, 40 to 80°C, preferably 45 to 75°C, further preferably 50 to 70°C, even more preferably 55 to 65°C, and most preferably 57 to 62°C. If the glass transition temperature is too low, the heat resistance and mechanical properties of the resin composition may be reduced, and conversely, if it is too high, the biodegradability and moldability of the resin composition may be reduced. The rigid biodegradable resin (particularly, polylactic acid-based resin) may be crystalline.

[0068] The melting point of the hard biodegradable resin (particularly polylactic acid resin) is, for example, 80 to 250°C, preferably 100 to 200°C, further preferably 130 to 180°C, even more preferably 140 to 170°C, and most preferably 150 to 160°C.

[0069] In this specification and claims, the glass transition temperature and melting point of the resin and resin composition can be measured using a differential scanning calorimeter (DSC), and in detail, can be measured by the method described in the examples below.

[0070] The acid value of the rigid biodegradable resin (particularly, polylactic acid-based resin) may be, for example, 0 to 100 mgKOH / g (e.g., 0.1 to 80 mgKOH / g), preferably 0.2 to 80 mgKOH / g, more preferably 0.3 to 60 mgKOH / g, and particularly about 0.5 to 30 mgKOH / g. If the acid value is too high, hydrolysis may occur easily. The hydroxyl value of the rigid biodegradable resin (particularly, polylactic acid-based resin) can also be selected from the same range as the acid value.

[0071] The hard biodegradable resin may account for 90% or more by mass of the biodegradable resin, preferably 95% or more by mass, more preferably 99% or more by mass, and most preferably 100% by mass. If the proportion of the hard biodegradable resin is too low, transparency and stretchability will decrease.

[0072] (Other resin components) The biodegradable resin (A) may contain other resin components in addition to the hard biodegradable resin, as long as the effects of the present invention are not impaired. Examples of other resin components include soft biodegradable resins and non-biodegradable resins. Among these, soft biodegradable resins are preferred because they can improve biodegradability.

[0073] The soft biodegradable resin may be any resin that is conventionally known as a soft biodegradable resin, and may be, for example, a resin with a flexural modulus of elasticity of less than 1000 MPa.

[0074] Examples of soft biodegradable resins include polyester-based resins such as polyethylene succinate copolymer (PES), polybutylene succinate copolymer (PBS), polybutylene succinate-adipate copolymer (PBSA), polyethylene sebacate copolymer, polybutylene succinate-terephthalate copolymer, polybutylene succinate-carbonate copolymer, polybutylene terephthalate-adipate copolymer (PBAT), hydroxybutyric acid-hydroxyhexanoic acid copolymer, polycaprolactone (PCL), and polycaprolactone-butylene succinate copolymer; and vinyl alcohol-based resins such as polyvinyl alcohol and ethylene-vinyl alcohol copolymer. These soft biodegradable resins can be used alone or in combination. Among these, aliphatic polyester-based resins such as PBS are preferred.

[0075] The weight average molecular weight of the soft biodegradable resin can be selected from the range of 1,000 to 1,000,000, for example, 10,000 to 1,000,000, preferably 20,000 to 800,000, further preferably 30,000 to 500,000, and even more preferably 40,000 to 400,000.

[0076] The glass transition temperature (Tg) of the soft biodegradable resin is, for example, -150°C to 20°C, preferably -130°C to 10°C, further preferably -125°C to 0°C, and even more preferably -120°C to -5°C.

[0077] The proportion of other resin components (especially soft biodegradable resins) in the biodegradable resin may be 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less. In particular, it is preferable that the biodegradable resin contains substantially no other resin components, and most preferably no other resin components at all. If the proportion of other resin components is too high, there is a risk of reduced transparency and stretchability.

[0078] (Proportion of biodegradable resin (A)) The biodegradable resin (A) may account for 50% by mass or more of the resin composition, for example, 50 to 99% by mass, preferably 70 to 97% by mass, further preferably 80 to 95% by mass, even more preferably 83 to 92% by mass, and most preferably 85 to 90% by mass. If the proportion of the biodegradable resin is too low, there is a risk that biodegradability will decrease.

[0079] [Epoxy compound (B)] The resin composition of the present invention contains an epoxy compound (B) having multiple epoxy groups. The multiple epoxy groups of the epoxy compound (B) partially crosslink the biodegradable resin (A), resulting in flexibility and thermoplasticity while also exhibiting stretchability. The epoxy compound (B) may be a bifunctional or higher epoxy compound, with bifunctional epoxy compounds being particularly preferred. Specifically, the number of epoxy groups in the molecule of the epoxy compound (B) is two or more, and can be selected from a range of, for example, about 2 to 10. From the viewpoint of improving flexibility and stretchability, the number is preferably 2 to 6, more preferably 2 to 4, even more preferably 2 or 3, and most preferably 2. If the number of epoxy groups is too large, not only flexibility but also stretchability may be reduced.

[0080] The epoxy compound (B) may have an aromatic skeleton and / or an alicyclic skeleton, but preferably has an aliphatic skeleton in order to improve flexibility. Furthermore, the epoxy group may be in the form of an alicyclic epoxy group, but preferably in the form of a glycidyl group in order to improve flexibility.

[0081] That is, as the epoxy compound (B), a compound having 2 to 4 epoxy groups in the molecule and having an aliphatic skeleton is preferred, a compound having 2 to 3 glycidyl groups and / or 2-methylglycidyl groups in the molecule and having an aliphatic skeleton is more preferred, a compound having two glycidyl groups and / or 2-methylglycidyl groups in the molecule and having an aliphatic skeleton is even more preferred, and a glycidyl ether compound represented by the above formula (1) (hereinafter referred to as "glycidyl ether compound (1)") is most preferred.

[0082] In the formula (1), examples of the alkylene group (straight-chain or branched-chain alkylene group) having 2 or more carbon atoms represented by A include C alkylene groups such as ethylene group, trimethylene group, propylene group, tetramethylene group, 1,2-butanediyl group, 1,3-butanediyl group, hexamethylene group, octamethylene group, and 1,10-decanediyl group. 2-12 These alkylene groups can be used alone or in combination of two or more. 2-6 Alkylene groups are preferred, C 2-4 An alkylene group is more preferred, and C 2-3 An alkylene group is more preferred, and an ethylene group is most preferred.

[0083] The repeat number n of the alkylene group A is 1 or more and can be selected, for example, from the range of integers from 1 to 15, and is preferably 1 to 10, more preferably 2 to 8, more preferably 2 to 6, even more preferably 3 to 5, and most preferably 4. If the repeat number n is too small, flexibility may decrease, and if it is too large, stretchability may decrease.

[0084] In this specification and claims, the "repeating number (number of moles added)" may be an average value (arithmetic mean value, additive mean value) or an average number of moles added, and preferred embodiments are the same as the preferred ranges (range of integers) described above.

[0085] When the number of repetitions n is 2 or more, the types of alkylene groups A may be the same or different, but are preferably the same.

[0086] R 1 is R 2 may be different from, but are preferably the same as, R 1 and R 2 is preferably a hydrogen atom.

[0087] Examples of the glycidyl ether compound (1) include C glycidyl ethers such as ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, and 1,6-hexanediol diglycidyl ether. 2-12 Alkylene glycol diglycidyl ethers; Poly-C such as diethylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, tritetramethylene glycol diglycidyl ether, tetraethylene glycol diglycidyl ether, tetrapropylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether 2-6 alkylene glycol diglycidyl ether.

[0088] These glycol ether compounds can be used alone or in combination of two or more. Among these glycol ether compounds, di- or octa-C 2-6 Alkylene glycol diglycidyl ethers are preferred, and di- to hexaC 2-4 Alkylene glycol diglycidyl ether is more preferred, and tri- to penta-C 2-3 Alkylene glycol diglycidyl ethers are more preferred, and tri- to pentaethylene glycol diglycidyl ethers are most preferred.

[0089] The proportion of the epoxy compound (B) can be selected from the range of, for example, about 0.1 to 30 parts by mass relative to 100 parts by mass of the biodegradable resin (A), and is, for example, 0.3 to 20 parts by mass, preferably 0.5 to 10 parts by mass, further preferably 1 to 8 parts by mass, more preferably 1.5 to 5 parts by mass, and most preferably 2 to 4 parts by mass. If the proportion of the epoxy compound (B) is too low, there is a risk of reduced stretchability, and if it is too high, there is a risk of reduced flexibility or bleeding out.

[0090] [Plasticizer (C)] The resin composition of the present invention may further contain a plasticizer (C) from the viewpoints of achieving high levels of transparency, stretchability, and flexibility and suppressing bleed-out of the epoxy compound.

[0091] The plasticizer (C) may be a conventional plasticizer used as a plasticizer for polyester resins.

[0092] Examples of conventional plasticizers include ester-based plasticizers such as aliphatic dicarboxylic acid esters, aromatic dicarboxylic acid esters, oxycarboxylic acid esters, and polyhydric alcohol fatty acid esters; phosphate-based plasticizers such as aliphatic phosphate esters, aromatic phosphate esters, and condensed phosphate esters; epoxy-based plasticizers such as alkyl epoxy stearates; amide-based plasticizers such as sulfonamides; and oligomer-based plasticizers such as ester oligomers and amide oligomers. These plasticizers can be used alone or in combination of two or more.

[0093] Among these plasticizers, ester-based plasticizers and oligomer-based plasticizers such as ester oligomers are preferred from the viewpoint of compatibility with hard biodegradable resins such as polylactic acid-based resins, with ester-based plasticizers being particularly preferred.

[0094] Preferred ester-based plasticizers include polycarboxylic acid esters and polyhydric alcohol esters.

[0095] The polycarboxylic acid ester may be a dicarboxylic acid ester or a polycarboxylic acid ester having three or more carboxyl groups.

[0096] Examples of the dicarboxylic acid ester include aliphatic dicarboxylic acid esters and aromatic dicarboxylic acid esters.

[0097] Examples of the aliphatic dicarboxylic acid ester include dialkyl aliphatic dicarboxylic acids, diesters of aliphatic dicarboxylic acids with glycol ethers, and diesters of aliphatic dicarboxylic acids with aralkyl alcohols and (poly)alkylene glycol monoalkyl ethers.

[0098] Examples of aliphatic dicarboxylic acid dialkyl include C 2 alkyl esters such as dibutyl adipate, dioctyl adipate, di-2-ethylhexyl adipate, diisodecyl adipate, dibutyl sebacate, dioctyl sebacate, diethyl azelate, dibutyl azelate, and di-2-ethylhexyl azelate. 2-10 Alkanedicarboxylic acid di-C 1-12 Alkyl (especially C 4-10 Alkanedicarboxylic acid di-C 4-8 alkyl esters).

[0099] Examples of diesters of aliphatic dicarboxylic acids and glycol ethers include diesters of aliphatic dicarboxylic acids and (poly)alkylene glycol monoalkyl ethers, such as bis(methyldiethylene glycol) adipate [or adipic acid di(methoxyethoxyethyl) ester], bis(butyldiethylene glycol) adipate, bis(methyldiethylene glycol) succinate, methyldiethylene glycol ethyl diethylene glycol adipate (or adipic acid methoxyethoxyethyl ethoxyethoxyethyl ester), and methyldiethylene glycol butyl diethylene glycol adipate. 2-10 Alkanedicarboxylic acids and di- or tetra-C 2-4 Alkylene glycol mono C 1-4 Diesters with alkyl ethers are also included.

[0100] Diesters of aliphatic dicarboxylic acids with aralkyl alcohols and (poly)alkylene glycol monoalkyl ethers include C esters such as benzyl methyl diethylene glycol adipate (or adipic acid methoxyethoxyethyl benzyl ester), benzyl ethyl diethylene glycol adipate, benzyl butyl diethylene glycol adipate, benzyl methyl diglycol succinate, and benzyl butyl diglycol succinate. 2-10 Alkanedicarboxylic acids and C 6-10 Aryl C 1-4 Alkyl alcohols and C 2-4 Alkylene glycol mono C 1-4 Diesters with alkyl ethers are also included.

[0101] Examples of aromatic dicarboxylic acid esters include dialkyl aromatic dicarboxylic acids, alkyl-aralkyl aromatic dicarboxylic acid esters, and diesters of aromatic dicarboxylic acids and glycol ethers.

[0102] Examples of aromatic dicarboxylic acid dialkyl include C phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, di-2-ethylhexyl phthalate, and diisodecyl phthalate. 8-14 Arenedicarboxylic acid diC 1-12 Alkyl esters (especially benzenedicarboxylic acid C 4-8 alkyl esters).

[0103] Aromatic dicarboxylic acid alkyl and aralkyl esters include C butyl benzyl phthalate and other 8-14 Arenedicarboxylic acid C 1-12 Alkyl C 6-10 Aryl C 1-4 Alkyl esters and the like.

[0104] Examples of the diesters of aromatic dicarboxylic acids and glycol ethers include diesters of aromatic dicarboxylic acids and (poly)alkylene glycol monoalkyl ethers, such as C bis(methyldiethylene glycol) phthalate (or di(methoxyethyl) phthalate). 8-14 Arenedicarboxylic acids (especially C 8-12 arenedicarboxylic acids) and di- or tetra-C 2-4 Alkylene glycol mono C 1-4 Diesters with alkyl ethers are also included.

[0105] The polycarboxylic acid ester having three or more carboxyl groups may be an ester of an aliphatic or aromatic carboxylic acid having about 3 to 8 (particularly 3 to 6) carboxyl groups. Examples of such polycarboxylic acid esters include citric acid esters such as tributyl citrate, acetyl tributyl citrate, and tri-2-ethylhexyl acetyl citrate; trimellitic acid esters such as trimethyl trimellitate, triethyl trimellitate, trioctyl trimellitate, and tri-2-ethylhexyl trimellitate; and pyromellitic acid esters such as tetraoctyl pyromellitate.

[0106] The polyhydric alcohol ester may be an ester of a polyhydric alcohol having three or more hydroxyl groups and a fatty acid. Examples of the polyhydric alcohol include alcohols having about 3 to 6 hydroxyl groups, such as sucrose, glycerin, diglycerin, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol, and sorbitol. Examples of the polyhydric alcohol fatty acid ester include glycerin diacetate mono-C 8-10 (Poly)C such as alkyl esters, triacetin, and diglycerin tetraacetate 3-10 Alkane polyol mono- or hexa-C 2-10 Alkanoates and the like.

[0107] These ester-based plasticizers can be used alone or in combination of two or more. Among these ester-based plasticizers, aliphatic dicarboxylic acid esters are preferred from the viewpoint of biodegradability, and C esters such as adipic acid esters are preferred. 4-8 Alkanedicarboxylic acid esters are particularly preferred.

[0108] The proportion of the plasticizer (C) may be 50 parts by mass or less (e.g., 0.1 to 50 parts by mass) relative to 100 parts by mass of the biodegradable resin (A), and is, for example, 1 to 30 parts by mass, preferably 3 to 25 parts by mass, further preferably 5 to 20 parts by mass, more preferably 10 to 15 parts by mass, and most preferably 11 to 13 parts by mass. If the proportion of the plasticizer (C) is too low, the effect of improving the flexibility of the resin composition may not be exerted, and conversely, if it is too high, the stretchability and transparency of the resin composition may decrease.

[0109] The proportion of the plasticizer (C) may be 10,000 parts by mass or less relative to 100 parts by mass of the epoxy compound (B), for example, 10 to 5,000 parts by mass, preferably 50 to 3,000 parts by mass, further preferably 100 to 1,000 parts by mass, more preferably 200 to 800 parts by mass, and most preferably 300 to 500 parts by mass. If the proportion of the plasticizer (C) is too low, the effect of improving the flexibility of the composition may not be exerted, whereas if it is too high, the elasticity and transparency of the resin composition may decrease or bleed out.

[0110] [Other ingredients] The resin composition of the present invention may further contain other components, which may be conventional additives that are blended into resins.

[0111] Commonly used additives include antiblocking agents, slip agents (or anti-scratch agents), stabilizers (antiaging agents, antioxidants, antiozonants, ultraviolet absorbers, light stabilizers, heat stabilizers, etc.), flame retardants, compatibilizers, lubricants, antistatic agents, crystal nucleating agents, colorants, preservatives, antifungal agents, etc. These additives can be used alone or in combination of two or more.

[0112] The total proportion of other components can be selected from the range of about 0.1 to 100 parts by mass per 100 parts by mass of the biodegradable resin (A), for example, 0.5 to 50 parts by mass, preferably 1 to 30 parts by mass, and more preferably 2 to 20 parts by mass.

[0113] [Characteristics and preparation method of resin composition] The resin composition of the present invention has flexibility and stretchability due to being crosslinked to an appropriate degree without impairing thermoplasticity. The crosslink density of the resin composition of the present invention may be 0.3 mmol / cc or more (e.g., 0.3 to 10 mmol / cc), for example, 0.3 to 5 mmol / cc, preferably 0.5 to 3 mmol / cc, more preferably 0.6 to 2 mmol / cc, more preferably 0.7 to 1.5 mmol / cc, even more preferably 0.8 to 1.3 mmol / cc, and most preferably 0.9 to 1.1 mmol / cc. If the crosslink density is too low, stretchability may decrease, and conversely, if it is too high, flexibility may decrease.

[0114] In this specification and claims, the crosslink density of the resin composition can be calculated based on the storage modulus obtained by measuring the dynamic viscoelasticity, and in detail, can be measured by the method described in the examples below.

[0115] The resin composition of the present invention has excellent flexibility. The elongation at break of the resin composition of the present invention (test speed: 10 mm / min) may be 10% or more (particularly 50% or more), for example, 100 to 1000%, preferably 200 to 800%, further preferably 300 to 700%, even more preferably 400 to 600%, and most preferably 450 to 550%. If the elongation at break is too low, the flexibility of the resin composition may decrease.

[0116] In this specification and claims, the elongation at break (elongation at break or elongation at break) of a resin composition can be measured in accordance with JIS K 7161, and more specifically, by the method described in the examples below.

[0117] The tensile modulus of elasticity of the resin composition of the present invention (test speed 10 mm / min) may be 1500 MPa or less (particularly 1000 MPa or less), for example, 10 to 500 MPa, preferably 30 to 300 MPa, further preferably 40 to 200 MPa, more preferably 50 to 100 MPa, and most preferably 60 to 80 MPa. If the tensile modulus is too high, the flexibility of the resin composition may decrease.

[0118] In this specification and claims, the tensile modulus of elasticity of the resin composition can be measured in accordance with JIS K 7161, and more specifically, by the method described in the examples below.

[0119] The resin composition of the present invention has thermoplasticity, excellent melt fluidity, and high moldability. The MFR (melt flow rate or melt flow index (MFI)) of the resin composition of the present invention (temperature: 190°C, load: 2.16 kgf) may be 3 g / 10 min or more (particularly 5 g / 10 min or more), for example, 5 to 50 g / 10 min, preferably 7 to 40 g / 10 min, further preferably 10 to 35 g / 10 min, more preferably 15 to 30 g / 10 min, and most preferably 20 to 25 g / 10 min. If the MFR is too low, moldability may be reduced.

[0120] In this specification and claims, the MFR of a resin composition can be measured in accordance with ISO 1133, and more specifically, by the method described in the examples below.

[0121] The glass transition temperature (Tg) of the resin composition of the present invention can be selected, for example, within a range of about 0 to 100°C, and is, for example, 5 to 55°C, preferably 10 to 50°C, further preferably 15 to 45°C, even more preferably 20 to 40°C, and most preferably 25 to 35°C.

[0122] The resin composition of the present invention also has excellent transparency. The haze of the resin composition of the present invention may be 50% or less (particularly 30% or less), for example, 0.1 to 50%, preferably 0.5 to 30%, further preferably 1 to 20%, more preferably 3 to 15%, and most preferably 5 to 13%. If the haze is too high, there is a risk of reduced transparency.

[0123] In this specification and claims, the haze of the resin composition can be measured using a spectrophotometer in accordance with JIS K 7105, and more specifically, by the method described in the examples below.

[0124] The resin composition of the present invention can be prepared by mixing a biodegradable resin (A), an epoxy compound (B) having multiple epoxy groups, and, if necessary, a plasticizer (C) and other components by a conventional method such as dry mixing or melt kneading. The resin composition may be in the form of pellets or the like. When melt kneading, the kneading temperature is, for example, 100 to 250°C, preferably 130 to 230°C, more preferably 150 to 220°C, more preferably 160 to 200°C, and most preferably 180 to 190°C. Conventional methods can be used for melt kneading, and for example, a twin-screw extrusion kneader may be used. By heating the resin composition of the present invention at the above-mentioned temperature, the biodegradable resin (A) can be appropriately crosslinked with the epoxy compound (B).

[0125] [Molded body] The molded article of the present invention may be formed from the resin composition. The shape of the molded article of the present invention is not particularly limited and can be selected depending on the application, and examples thereof include one-dimensional structures such as linear or thread-like structures, two-dimensional structures such as film-like, sheet-like, and plate-like structures, and three-dimensional structures such as block-like, rod-like, tubular, and hollow structures.

[0126] The molded article of the present invention can be produced by molding the resin composition by a conventional molding method, such as compression molding, injection molding, injection compression molding, extrusion molding, transfer molding, blow molding, pressure molding, and casting molding.

[0127] When the molded article of the present invention is a film-like or sheet-like two-dimensional structure, the molded article of the present invention can be produced by forming (or molding) the resin composition into a film using a conventional film-forming method, such as melt extrusion, injection molding, inflation molding, casting (solvent casting), or calendaring.

[0128] When the molded article of the present invention is produced by injection molding, the cylinder temperature is, for example, 130 to 250°C, preferably 150 to 230°C, further preferably 180 to 210°C, even more preferably 185 to 205°C, and most preferably 190 to 200°C. [Example]

[0129] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. The raw materials used are as follows, and the properties and evaluation of the obtained resin compositions and test pieces were measured and evaluated as follows.

[0130] [Ingredients used] PLA (polylactic acid): manufactured by Anhui Fengyuan Group Co., Ltd.; FY804, melting point 150-160°C, L-isomer content 95.5 mol%, D-isomer content 4.5 mol%, MFR (temperature 190°C, load 2.16 kgf) 4 g / 10 min, glass transition temperature 60°C PBS (polybutylene succinate): Manufactured by China Xinjiang Lanshan Tunhe Chemical Co., Ltd.; TH803S Epoxy compound A: Denacol EX-821 (tetraethylene glycol diglycidyl ether) manufactured by Nagase ChemteX Corporation Epoxy compound B: Denacol EX-920 (tripropylene glycol diglycidyl ether) manufactured by Nagase ChemteX Corporation Adipic acid ester: "DAIFATTY-101" manufactured by Daihachi Chemical Industry Co., Ltd.

[0131] [Hayes] The resin compositions obtained in the examples and comparative examples were hot pressed at 160°C to produce sheets with a thickness of 0.1 mm. The haze (%) of the obtained sheets was measured using a spectrophotometer in accordance with JIS K 7105. The measuring device used was a "CM-36dG" manufactured by Konica Minolta, Inc.

[0132] [Crosslink density and glass transition temperature] The resin compositions obtained in the examples and comparative examples were hot-pressed at 160°C to produce sheets with a thickness of 0.3 mm. The obtained sheets were cut into test pieces measuring 5 mm in width and 17 mm in length, and dynamic viscoelasticity measurements were carried out. The measurement conditions were a temperature range of 0 to 100°C, a heating rate of 1°C / min, and an N2 atmosphere (50 mL / min), and the apparatus used was a "DTG-60" manufactured by Shimadzu Corporation. The crosslink density (mmol / cc) was calculated from the storage modulus obtained by the dynamic viscoelasticity measurement using the following formula:

[0133] n=E' / 3RT [In the formula, n represents the crosslink density (mmol / cc), E' represents the storage modulus (Pa), R represents the gas constant (=8.314 J / mol K), and T represents the absolute temperature (K)]

[0134] Furthermore, the glass transition temperature was calculated from the peak position of the ratio (tan δ) of the storage modulus to the loss modulus obtained by dynamic viscoelasticity measurement.

[0135] [Stretchability] The resin compositions obtained in the examples and comparative examples were injection molded at 195°C using a small injection molding machine to prepare dumbbell-shaped test pieces with a thickness of 2 mm and a length of 72 mm. Using a small benchtop testing machine (Shimadzu Corporation's "EZ-Graph"), the crosshead speed was set to 10 mm / min, and the test was stopped after 20 mm of stretching to prepare a 92 mm-long test piece for stretch evaluation. The resulting test piece for stretch evaluation was removed from the benchtop testing machine and left at 23°C for 1 hour. The length of the test piece was evaluated. If the test piece had shrunk to +2 mm or less of the length before stretching, it was evaluated as "stretchable," and if it remained longer than +2 mm of the length before stretching, it was evaluated as "not stretchable." Note that if the test piece broke before stretching 20 mm, it was evaluated as "broken."

[0136] [Tensile test (elongation at break and tensile modulus)] The resin composition was measured for elongation at break and tensile modulus of elasticity using a small tabletop testing machine (Shimadzu Corporation, "EZ-Graph") in accordance with JIS K 7161. The test conditions were a crosshead speed of 10 mm / min, a test piece length of 750 mm, a width of 10 mm, and a thickness of 2 mm. A 100 N load cell was used.

[0137] [MFR] The resin composition was measured in accordance with ISO 1133 under conditions of a holding time of 5 minutes, a temperature of 190°C, and a test load of 2.16 kgf.

[0138] Example 1 As raw materials, 300 g of PLA and 45 g of epoxy compound A were mixed, and the mixture was melt-kneaded at 185°C using a twin-screw extrusion kneader to produce pellets.

[0139] The obtained pellets were hot pressed at 160°C to produce sheet-like test pieces with a thickness of 0.1 mm for haze evaluation and 0.3 mm for dynamic viscoelasticity measurement.

[0140] The resulting resin pellets were injection molded at 195°C to produce test pieces for stretchability evaluation and tensile test. The injection-molded products had good transparency. Furthermore, the test pieces had stretchability, a large elongation at break, a low tensile modulus, and excellent flexibility.

[0141] Example 2 An experiment was carried out in the same manner as in Example 1, except that 300 g of PLA, 9 g of epoxy compound A, and 36 g of adipic acid ester were used as raw materials. As a result of the test, the test piece was excellent in transparency, stretchability, and flexibility.

[0142] Example 3 An experiment was carried out in the same manner as in Example 1, except that 300 g of PLA, 15 g of epoxy compound A, and 30 g of adipic acid ester were used as raw materials. As a result of the test, the test piece was excellent in transparency, stretchability, and flexibility.

[0143] Example 4 An experiment was carried out in the same manner as in Example 1, except that 300 g of PLA, 15 g of epoxy compound B, and 30 g of adipic acid ester were used as raw materials. As a result of the test, the test piece was excellent in transparency, stretchability, and flexibility.

[0144] Comparative Example 1 An experiment was carried out in the same manner as in Example 1, except that 300 g of PLA was used as the raw material. As a result of the test, the test piece had low stretchability and flexibility.

[0145] Comparative Example 2 An experiment was carried out in the same manner as in Example 1, except that 300 g of PLA and 45 g of adipic acid ester were used as raw materials. As a result of the test, the test piece was excellent in flexibility and transparency, but had low stretchability.

[0146] Comparative Example 3 An experiment was carried out in the same manner as in Example 1, except that 255 g of PLA, 45 g of PBS, and 45 g of epoxy compound A were used as raw materials. As a result of the test, the test piece had excellent flexibility, but low stretchability and transparency.

[0147] Comparative Example 4 An experiment was carried out in the same manner as in Example 1, except that 210 g of PLA, 90 g of PBS, and 45 g of epoxy compound A were used as raw materials. As a result of the test, the test piece had excellent flexibility, but low stretchability and transparency.

[0148] Table 1 shows the evaluation results of the resin compositions and test pieces obtained in Examples 1 to 4 and Comparative Examples 1 to 4.

[0149] [Table 1]

[0150] As is clear from the results in Table 1, the test pieces of Examples 1 to 4 not only had excellent transparency, but also, unexpectedly, excellent stretchability and flexibility, despite containing a high proportion of hard biodegradable resin. In particular, in Example 1, slight bleeding of the epoxy compound was observed after long-term storage, but in Examples 2 to 4, no bleeding was observed even after long-term storage.

[0151] In contrast, the test piece obtained in Comparative Example 1 had low stretchability and broke, and also had low flexibility.

[0152] Moreover, the test piece obtained in Comparative Example 2 had low stretchability.

[0153] Furthermore, the test pieces obtained in Comparative Examples 3 and 4 had low stretchability and also low transparency. [Industrial Applicability]

[0154] The resin composition of the present invention is highly biodegradable and can be used in a variety of fields, including paints, antistatic agents, inks, adhesives, pressure-sensitive adhesives, electrical and electronic materials (e.g., carrier transport agents, light emitters, organic photoreceptors, etc.), electrical and electronic components or devices (e.g., optical lenses, optical films, optical disks, inkjet printers, digital paper, organic semiconductor lasers, dye-sensitized solar cells, etc.), and mechanical parts or devices (e.g., automobiles, aerospace materials, sensors, etc.). In particular, due to its excellent mechanical properties, it can be easily molded by extrusion molding, injection molding, etc., and is suitable for use in various molded components (e.g., molded articles such as casings and housings), containers (containers for food, daily necessities, electrical and electronic devices and parts, etc.), packaging materials such as films and sheets, and bags such as garbage bags. Due to its excellent transparency and stretchability, it is particularly suitable for use as a packaging material such as stretch film. Furthermore, its high biodegradability can also be used to solve the emerging problem of microplastics (particularly in the ocean), which has become a problem in recent years.

Claims

1. A resin composition comprising a biodegradable resin (A) containing a rigid biodegradable resin and an epoxy compound (B) having a plurality of epoxy groups, wherein the proportion of the rigid biodegradable resin in the biodegradable resin (A) is 90 mass% or more.

2. 2. The resin composition according to claim 1, wherein the hard biodegradable resin is a polylactic acid-based resin.

3. 3. The resin composition according to claim 1, wherein the epoxy compound (B) is a difunctional epoxy compound.

4. The bifunctional epoxy compound is represented by the following formula (1): 【Chemical 1】 (In the formula, A represents an alkylene group having 2 or more carbon atoms, n represents an integer of 1 or more, and R １ and R ２ each independently represents a hydrogen atom or a methyl group) 4. The resin composition according to claim 3, wherein the glycidyl ether compound is represented by the formula:

5. 3. The resin composition according to claim 1, wherein the proportion of the epoxy compound (B) is 0.5 to 20 parts by mass per 100 parts by mass of the biodegradable resin (A).

6. The resin composition according to claim 1 or 2, further comprising a plasticizer (C).

7. 7. The resin composition according to claim 6, wherein the plasticizer (C) is an ester-based plasticizer.

8. 7. The resin composition according to claim 6, wherein the proportion of the plasticizer (C) is 50 to 1000 parts by mass per 100 parts by mass of the epoxy compound (B).

9. 3. The resin composition according to claim 1, which has a haze of 30% or less.

10. 3. The resin composition according to claim 1, which has a melt flow rate of 5 g / 10 min or more at a temperature of 190° C. and a load of 2.16 kgf.

11. A molded article formed from the resin composition according to claim 1 or 2.

12. The molded article according to claim 11, which is a film or sheet.

13. The method for producing a molded article according to claim 11, wherein a resin composition containing a biodegradable resin (A) including a hard biodegradable resin and an epoxy compound (B) having a plurality of epoxy groups is heated, melted, and molded.

14. A method for improving at least one of the properties of transparency, stretchability, and flexibility of a resin composition comprising a biodegradable resin (A) containing a rigid biodegradable resin and an epoxy compound (B) having a plurality of epoxy groups, by adjusting the proportion of the rigid biodegradable resin in the biodegradable resin (A) to 90 mass% or more.

Images