JP2015063672A - Aliphatic polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aliphatic polyester resin composition which has a sufficient molecular weight and excellent mechanical strength when being produced, but begins to reduce the molecular weight immediately in soil, in water, or in a humid condition under a relatively mild temperature condition.SOLUTION: Provided is an aliphatic polyester resin composition comprising an aliphatic polyester resin (A) and an organic phosphorus compound (B) represented by the following formula (1). [In the formula (1), X represents a hydrogen atom or OH; n represents an integer of 1 to 20; and m represents 1 or 2.] A content of the organic phosphorus compound (B) is 0.3 to 5 pts.mass relative to 100 pts.mass of the aliphatic polyester resin (A). Also provided is a method for producing the aliphatic polyester resin composition comprising melt kneading 0.3 to 5 pts.mass of the organic phosphorus compound (B) represented by the formula (1) in 100 pts.mass of the aliphatic polyester resin (A).

Description

  The present invention relates to an aliphatic polyester resin composition, and more particularly to an aliphatic polyester resin composition with controlled degradation characteristics under humid conditions.

  Biodegradable resins such as aliphatic polyesters are used in films, sheets, fibers, molded products, etc. for the purpose of reducing the environmental burden. However, in applications that require rapid degradation after use, such as agricultural applications, soil reforming applications, and underground resource mining applications such as oil and gas, the mechanical strength required in the initial use and the decomposition rate required after use are It is difficult to achieve both, which is a challenge.

For example, a proppant solution containing a polymer may be used as a sealant (support material) for a rift formed in shale by hydraulic fracturing during shale gas mining (Non-patent Document 1).
Such a polymer can reduce the friction of the proppant solution and improve the efficiency of shale gas mining. However, in recent years, it has been regarded as a problem that the polymer introduced into the ground in this way contaminates the aquifer and the surface water source, and a biodegradable resin that rapidly decomposes after being put into the ground is expected. .

  On the other hand, for the purpose of improving the color tone, heat stability, moist heat resistance and moldability of the resin, it has been proposed to blend an organic phosphorus compound at the time of polymerization or by melt kneading (for example, Patent Documents 1 to 7). ).

JP 2007-92048 A JP 2001-49097 A Special table 2008-520806 JP 2006-249152 A International Publication No. 06/118096 International Publication No. 10/053167 Japanese Patent Laid-Open No. 9-104809

Ken Ihara, “Impact of Shale Gas”, Oil / Natural Gas Review, Japan Petroleum Natural Gas / Metal Mineral Resources Organization, 2010.5 Vol.44 No.3, P15-38

  However, Patent Document 1 suggests that the hydrolysis resistance decreases when the amount of the organophosphorus compound is large, but the degradation characteristics required by the present inventors are not obtained. It's real. In addition, if a large amount of a phosphorus stabilizer is added during polymerization of an aliphatic polyester for the purpose of improving the color tone of the resin or maintaining the molecular weight, an aliphatic polyester having a sufficient degree of polymerization may not be obtained or the color tone may not be stable. There was a problem.

  Patent Documents 2 to 6 describe a resin composition in which an organic phosphorus compound is added to an aliphatic polyester, but there is no suggestion that hydrolyzability is improved by adding an organic phosphorus compound.

  In addition, Patent Document 7 has a description that 0.2 part by weight of the organophosphorus compound defined by the present invention is added to the aliphatic polyester, but the reason for adding the organophosphorus compound in this document is related to suppression of polymer cleavage. Therefore, it is used for the purpose opposite to the improvement of the hydrolyzability aimed by the present invention.

  The present invention has been made in view of the above situation, and its purpose is to have a sufficient molecular weight at the time of production by a simple production method, excellent in mechanical strength, and particularly under high humidity conditions such as in soil and water. It is an object to provide an aliphatic polyester resin composition having controlled degradation characteristics.

  As a result of intensive studies to solve the above problems, the present inventors have added a certain amount of an organophosphorus compound having a specific chemical structure to the aliphatic polyester resin, thereby having a sufficient molecular weight at the time of production, -It has been found that controlled degradation characteristics can be imparted under humid conditions such as in water. The present invention has been accomplished based on these findings.

That is, the gist of the present invention is as follows (1) to (9).
(1) A resin composition containing an aliphatic polyester resin (A) and an organic phosphorus compound (B) represented by the following formula (1), wherein the organic phosphorus with respect to 100 parts by mass of the aliphatic polyester resin (A) Content of a compound (B) is 0.3-5 mass parts, The aliphatic polyester resin composition characterized by the above-mentioned.

[In Formula (1), X shows a hydrogen atom or OH, n shows the integer of 1-20, m shows 1 or 2. ]

(2) The aliphatic polyester resin (A) contains an aliphatic polyester mainly composed of a diol and a dicarboxylic acid, and when the content is 100 parts by mass of the entire aliphatic polyester resin (A), It is 50-100 mass parts, The aliphatic polyester resin composition as described in (1) characterized by the above-mentioned.
(3) The aliphatic polyester resin composition according to (2), wherein the diol is 1,4-butanediol and the dicarboxylic acid is succinic acid.
(4) The aliphatic polyester resin according to any one of (1) to (3), wherein the aliphatic polyester resin (A) as a raw material has an intrinsic viscosity (IV) of 0.6 to 1.8. Resin composition.
(5) When the aliphatic polyester resin (A) contains an aliphatic polyester containing oxycarboxylic acid as a main component and the content is 100 parts by mass of the entire aliphatic polyester resin (A), It is 50 mass parts, The aliphatic polyester resin composition in any one of (1)-(4) characterized by the above-mentioned.
(6) The aliphatic polyester resin composition according to any one of (1) to (5), wherein the aliphatic polyester resin composition has an intrinsic viscosity (IV) of 0.6 to 1.8.
(7) The inherent viscosity retention of the aliphatic polyester resin composition with respect to the aliphatic polyester resin (A) as a raw material is 60 to 100%, as described in any one of (1) to (6) Aliphatic polyester resin composition.
(8) The aliphatic polyester resin composition according to any one of (1) to (7), wherein the aliphatic polyester resin composition is used for a filler for a void for underground resource mining.
(9) In the method for producing a resin composition containing the aliphatic polyester resin (A) and the organophosphorus compound (B), the formula (1) is used for 100 parts by mass of the aliphatic polyester resin (A). The manufacturing method of the aliphatic polyester resin composition characterized by melt-kneading 0.3-5 mass parts of organophosphorus compounds (B) made using an extruder.

  Since the aliphatic polyester resin composition of the present invention has a sufficient molecular weight during production, it has excellent mechanical properties. In addition, it has controlled decomposition characteristics under humid conditions such as soil and water, that is, its molecular weight decreases rapidly even under mild temperature conditions, so it can be used for agricultural use, soil reforming, underground resource extraction such as crude oil and gas. It is particularly useful for applications that require rapid degradation after use, such as applications.

  Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention. In addition, in this specification, when the expression “to” is used, it is used in a sense including numerical values or physical values before and after that.

1. Aliphatic polyester resin composition The aliphatic polyester resin composition of the present invention is a resin composition containing an aliphatic polyester resin (A) and an organic phosphorus compound (B) represented by the following formula (1). The content of the organophosphorus compound (B) with respect to 100 parts by mass of the aliphatic polyester resin (A) is 0.3 to 5 parts by mass. Hereinafter, the “aliphatic polyester resin composition of the present invention” may be abbreviated as “the resin composition of the present invention”.

[In the formula (1), X represents a hydrogen atom or OH, n represents an integer of 1 to 20, and m represents 1 or 2.
Indicates. ]

1.1. Aliphatic polyester resin (A)
In the present invention, the aliphatic polyester resin (A) is not particularly limited as long as the molar ratio of the aliphatic structure is a maximum ratio with respect to the entire structure. For example, the aliphatic polyester resin (A) is partially aromatic in addition to the aliphatic structure. It may be an aliphatic aromatic polyester having a group structure. More specifically, for example, an aliphatic polyester mainly composed of diol and dicarboxylic acid, an aliphatic polyester mainly composed of oxycarboxylic acid (hydroxycarboxylic acid), and an aliphatic fragrance mainly composed of diol and dicarboxylic acid. Group polyesters, and mixtures thereof. Of these, aliphatic polyesters mainly composed of diol and dicarboxylic acid are preferred.

  Here, “being as a main component” means that the monomer component is obtained by polymerization reaction using 50 mol% or more of each monomer component. The amount of each monomer component used is preferably 60 mol% or more, more preferably 70 mol% or more, and still more preferably 80 mol% or more.

1.1.1. Aliphatic polyester mainly composed of diol and dicarboxylic acid The aliphatic polyester mainly composed of diol and dicarboxylic acid is an aliphatic diol unit represented by the following formula (2) and a fat represented by the following formula (3). An aliphatic polyester resin comprising an aliphatic dicarboxylic acid unit.

—O—R ¹ —O— (2)
[In the formula (2), R ¹ represents a divalent chain aliphatic hydrocarbon group and / or a divalent alicyclic hydrocarbon group which may have an oxygen atom in the chain, and is a copolymer If it is, it is not limited to one type. ]

^-OC-R 2 -CO- (3)
[In the formula (3), R ² represents a direct bond or a divalent chain aliphatic hydrocarbon group and / or a divalent alicyclic hydrocarbon group, and is copolymerized. It is not limited to one type. ]

  Although it does not specifically limit as an aliphatic diol which gives the diol unit of Formula (2), From a viewpoint of a moldability or mechanical strength, a C2-C10 aliphatic diol is preferable and a C4-C6 aliphatic diol. Is particularly preferred. Specifically, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptane Diol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, neopentyl glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, 1,2-cyclohexanediol, 1, Examples include 4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, and 1,4-butanediol is particularly preferable. The above aliphatic diols may be used alone or in combination of two or more in any ratio and combination.

  Although it does not specifically limit as a dicarboxylic acid component which gives the dicarboxylic acid unit of Formula (3), A C2-C40 aliphatic dicarboxylic acid is preferable and a C4-C10 aliphatic dicarboxylic acid is especially preferable. Specific examples include succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, and dimer acid. Of these, succinic acid, adipic acid and sebacic acid are preferred, succinic acid and adipic acid are more preferred, and succinic acid is particularly preferred. The above aliphatic dicarboxylic acids may be used alone or in combination of two or more in any ratio and combination.

  Specific examples of the aliphatic polyester mainly composed of diol and dicarboxylic acid include polybutylene succinate, polybutylene succinate adipate, and the like.

  When the aliphatic dicarboxylic acid is succinic acid, by setting the amount of structural units derived from succinic acid within a predetermined range, when used in applications where rapid degradation is required after use, moderate biodegradability is obtained. It becomes possible. The proportion of structural units derived from succinic acid in the total aliphatic dicarboxylic acid units is preferably 50 to 100 mol%, more preferably 80 to 100 mol%, still more preferably 90 to 100 mol%.

  Further, when the aliphatic dicarboxylic acid is succinic acid and adipic acid, moderate biodegradability under normal conditions is possible by setting the amount of structural units derived from succinic acid and adipic acid within a predetermined range, and resistance to It becomes easier to impart impact properties. The proportion of structural units derived from succinic acid in the total aliphatic dicarboxylic acid units is preferably 50 to 95 mol%, more preferably 60 to 93 mol%, still more preferably 70 to 90 mol%. The ratio of the structural unit derived from adipic acid in the acid unit is preferably 5 to 50 mol%, more preferably 7 to 40 mol%, and still more preferably 10 to 30 mol%.

  Furthermore, the aliphatic polyester resin mainly comprising diol and dicarboxylic acid in the present invention may have a repeating unit derived from aliphatic oxycarboxylic acid (aliphatic oxycarboxylic acid unit). Specific examples of the aliphatic oxycarboxylic acid that gives an aliphatic oxycarboxylic acid unit include, for example, lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxycaproic acid, 6-hydroxycaproic acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, 3-hydroxyvaleric acid, malic acid, citric acid, etc., or lower Examples thereof include alkyl esters and intramolecular esters. In addition, lactone compounds such as ε-caprolactone are also included in the aliphatic oxycarboxylic acid in the present invention. When optical isomers exist in these, any of D-form, L-form and racemic form may be sufficient, and the form may be solid, liquid, or aqueous solution. Of these, lactic acid, glycolic acid, malic acid, and citric acid are particularly preferred. One of these aliphatic oxycarboxylic acids may be used alone, or two or more thereof may be used in any ratio and combination.

  The amount of the aliphatic oxycarboxylic acid unit is preferably 20 mol% or less, more preferably 10 mol% or less, and still more preferably in the total aliphatic dicarboxylic acid unit of the aliphatic polyester resin (A) from the viewpoint of moldability. 5 mol% or less.

  In addition, the aliphatic polyester mainly composed of diol and dicarboxylic acid may have a chain length extended by a coupling agent or the like.

  Examples of the coupling agent include diisocyanate, oxazoline, diepoxy compound, acid anhydride and the like. Specific examples include 2,4-tolylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, and the like. It is preferable that these addition amounts are 0.1-5 mass parts with respect to 100 mass parts of aliphatic polyester resin (A).

  Aliphatic polyesters mainly composed of diol and dicarboxylic acid are produced by known methods (methods described in JP 2012-144744 A, JP 2010-195989 A, JP 2009-173884 A, etc.). be able to. For example, a general method of melt polymerization in which an esterification reaction and / or transesterification reaction between the aliphatic dicarboxylic acid and the aliphatic diol is performed, and then a polycondensation reaction under reduced pressure is performed, or an organic solvent is used. Although it can manufacture also by the well-known solution heating dehydration condensation method used, the method of manufacturing by the melt polymerization performed without a solvent from a viewpoint of economical efficiency or the simplicity of a manufacturing process is preferable.

Examples of usable products (commercially available products) include polybutylene succinate resin GS Pla (registered trademark) (polybutylene succinate, polybutylene succinate adipate, etc.) manufactured by Mitsubishi Chemical Corporation, polybutylene succinate resin manufactured by Showa Denko KK Examples include Bionore (registered trademark).

In the present invention, the aliphatic polyester having diol and dicarboxylic acid as main components preferably has the following physical properties.
The lower limit of the weight average molecular weight is preferably 10,000 or more, more preferably 20,000 or more, further preferably 50,000 or more, and the upper limit is preferably 1,000,000 or less, more preferably 500,000 or less. More preferably, it is 400,000 or less. By setting the weight average molecular weight within the above range, it is advantageous in terms of moldability and mechanical strength. The weight average molecular weight is based on a value obtained by measuring polystyrene as a standard substance by gel permeation chromatography (GPC).

  When measured at 190 ° C. and 2.16 kg, the lower limit of the melt flow rate (MFR) is preferably 0.1 g / 10 min or more, and the upper limit is preferably 150 g / 10 min or less, more preferably 120 g / 10 min. Hereinafter, it is particularly preferably 100 g / 10 min or less. By setting the melt flow rate within the above range, moldability and mechanical strength are improved.

  The lower limit of the melting point is preferably 70 ° C. or higher, more preferably 75 ° C. or higher, and the upper limit is preferably 250 ° C. or lower, more preferably 200 ° C. or lower, and particularly preferably 150 ° C. or lower. When there are a plurality of melting points, at least one melting point is preferably within the above range.

  The intrinsic viscosity (IV) is usually 0.6 or more, preferably 0.8 or more, more preferably 1.0 or more, and the upper limit is usually 1.8 or less, preferably 1.6 or less, more preferably 1. 4 or less. If the intrinsic viscosity is too small, the mechanical properties of the molded product may be lowered. If the intrinsic viscosity is too large, the melt viscosity becomes too high during molding and the moldability may be lowered. The intrinsic viscosity (IV) is based on a value measured at 30 ° C. using a mixed solvent of phenol / tetrachloroethane (mass ratio 1/1).

  In the present invention, the physical properties of the aliphatic polyester resin (A) used as a raw material for the resin composition are substantially the same as described above.

  The content of the aliphatic polyester mainly composed of diol and dicarboxylic acid in the aliphatic polyester resin (A) is preferably 50 masses when the entire aliphatic polyester resin (A) is 100 mass parts. Part or more, more preferably 70 parts by weight or more, particularly preferably 90 parts by weight or more, and the upper limit is preferably 100 parts by weight or less. When the content is within the above range, moderate biodegradability is possible particularly when used in applications that require rapid degradation after use as described above.

1.1.2. Aliphatic polyester mainly composed of oxycarboxylic acid The aliphatic polyester mainly composed of oxycarboxylic acid is an aliphatic polyester comprising at least one aliphatic oxycarboxylic acid unit.

  Specific examples of the aliphatic oxycarboxylic acid that gives an aliphatic oxycarboxylic acid unit include, for example, lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxycaproic acid, 6-hydroxycaproic acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, 3-hydroxyvaleric acid, malic acid, citric acid, etc., or lower Examples thereof include alkyl esters and intramolecular esters. When optical isomers exist in these, any of D-form, L-form and racemic form may be sufficient, and the form may be solid, liquid, or aqueous solution. Among these, lactic acid, glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 6-hydroxycaproic acid, and 3-hydroxyvaleric acid are preferable. One of these aliphatic oxycarboxylic acids may be used alone, or two or more thereof may be used in any ratio and combination.

  Specific examples of the aliphatic polyester mainly composed of oxycarboxylic acid include polylactic acid, polyglycolic acid, poly-3-hydroxybutyrate, poly-4-hydroxybutyrate, poly (3-hydroxybutyrate-co-3- Hydroxyvalerate), polycaprolacto and the like. Of these, polylactic acid is particularly preferred.

The polylactic acid contained in the polylactic acid resin preferably has a molar ratio of D-lactic acid: L-lactic acid = 100: 0 to 85:15 or 0: 100 to 15:85. Also,
It is also possible to blend other polylactic acids having different constituent ratios of D-lactic acid and L-lactic acid. A polylactic acid resin having only D-lactic acid or L-lactic acid as a structural unit becomes a crystalline resin, has a high melting point, and tends to have excellent heat resistance and mechanical properties.

  Furthermore, the polylactic acid resin may be a copolymer of the above-described polylactic acid and other hydroxycarboxylic acid units, and may contain a small amount of a chain extender residue. As other hydroxycarboxylic acid units, optical isomers of lactic acid (D-lactic acid for L-lactic acid, L-lactic acid for D-lactic acid), glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid Bifunctional aliphatic hydroxycarboxylic acids such as 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-methyllactic acid, 2-hydroxycaproic acid, and the like, and Examples include lactones such as caprolactone, butyrolactone, and valerolactone. Such other hydroxycarboxylic acid units are preferably used in less than 15 mol% in the polylactic acid resin.

  Examples of the chain extender residue that may be contained in the resin include a residue derived from the above-described coupling agent.

  Aliphatic polyesters mainly composed of oxycarboxylic acid, such as polylactic acid resin, are prepared by known methods such as condensation polymerization and ring-opening polymerization (JP-A-9-151244, JP-A-8-12750, international publication). No. 00/078839, etc.). For example, in the condensation polymerization method, a polylactic acid resin having an arbitrary composition and crystallinity can be obtained by directly dehydrating condensation polymerization of L-lactic acid, D-lactic acid, or a mixture thereof. Further, in the ring-opening polymerization method (lactide method), a lactate which is a cyclic dimer of lactic acid can be used to obtain a polylactic acid resin using an appropriate catalyst while using a polymerization regulator or the like as necessary. it can. The lactide includes L-lactide which is a dimer of L-lactic acid, D-lactide which is a dimer of D-lactic acid, DL-lactide which is a dimer of D-lactic acid and L-lactic acid. These are mixed as necessary and polymerized to obtain a polylactic acid resin having an arbitrary composition and crystallinity.

  Examples of usable products (commercial products) include polylactic acid resin Ingeo (registered trademark) manufactured by Nature Works.

  The lower limit of the weight average molecular weight of the polylactic acid resin that can be used in the present invention is preferably 60,000 or more, more preferably 80,000 or more, particularly preferably 100,000 or more, and the upper limit is preferably 700,000 or less. , More preferably 400,000 or less, particularly preferably 300,000 or less. When the weight average molecular weight is less than 60,000, practical physical properties such as mechanical properties and heat resistance are inferior, and when it is more than 700,000, the melt viscosity tends to be too high and the molding processability tends to be inferior.

  The content of the aliphatic polyester mainly composed of oxycarboxylic acid in the aliphatic polyester resin (A) is preferably 1 part by mass when the total amount of the aliphatic polyester resin (A) is 100 parts by mass. Above, more preferably 3 parts by mass or more, particularly preferably 5 parts by mass or more, and the upper limit is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and particularly preferably 30 parts by mass or less. By making content into the said range, hydrolyzability may improve.

1.1.3. Aliphatic aromatic polyester mainly composed of diol and dicarboxylic acid An aliphatic aromatic polyester mainly composed of diol and dicarboxylic acid is an aliphatic diol unit represented by the following formula (4): ) And an aromatic dicarboxylic acid unit represented by the following formula (6) as essential components. However,
It may have an oxycarboxylic acid unit.

—O—R ³ —O— (4)
[In the formula (4), R ³ represents a divalent chain aliphatic hydrocarbon group and / or a divalent alicyclic hydrocarbon group which may have an oxygen atom in the chain, and is a copolymer If it is, it is not limited to one type. ]

—OC—R ⁴ —CO— (5)
[In the formula (5), R ⁴ represents a direct bond or a divalent chain aliphatic hydrocarbon group and / or a divalent alicyclic hydrocarbon group, and is copolymerized. It is not limited to one type. ]

—OC—R ⁵ —CO— (6)
[In formula (6), R ⁵ represents a divalent aromatic hydrocarbon group, and is not limited to one type when copolymerized. ]

  Although it does not specifically limit as an aliphatic diol which gives the diol unit of Formula (4), From a viewpoint of a moldability or mechanical strength, a C2-C10 aliphatic diol is preferable and a C4-C6 aliphatic diol. Is particularly preferred. Specifically, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptane Diol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, neopentyl glycol, diethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, 1,2-cyclohexanediol, 1, Examples include 4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, and 1,4-butanediol is particularly preferable. The above aliphatic diols may be used alone or in combination of two or more in any ratio and combination.

  Although it does not specifically limit as an aliphatic dicarboxylic acid component which gives the aliphatic dicarboxylic acid unit of Formula (5), C2-C40 aliphatic dicarboxylic acid is preferable, C4-C10 aliphatic dicarboxylic acid is especially preferable. Specific examples include succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, and dimer acid. Of these, succinic acid, adipic acid and sebacic acid are preferred, succinic acid and adipic acid are more preferred, and succinic acid is particularly preferred. The above aliphatic dicarboxylic acids may be used alone or in combination of two or more in any ratio and combination.

  Although it does not specifically limit as an aromatic dicarboxylic acid component which gives the aromatic dicarboxylic acid unit of Formula (6), A terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, etc. are mentioned. These may be acid anhydrides. Examples of the aromatic dicarboxylic acid derivatives include lower alkyl esters of these aromatic dicarboxylic acids. Among these, terephthalic acid, isophthalic acid, or their lower alkyl (e.g., alkyl having 1 to 4 carbon atoms) ester derivatives are preferable, and in particular, terephthalic acid and / or methyl ester of terephthalic acid, terephthalic acid and / or terephthalic acid. A mixture containing a methyl ester of an acid and isophthalic acid and / or a methyl ester of isophthalic acid is preferred. These may be used individually by 1 type, and may mix and use 2 or more types.

  As specific examples of the aliphatic aromatic polyester, polybutylene terephthalate alkylate is preferable, polybutylene adipate terephthalate or polybutylene succinate terephthalate is more preferable, and polybutylene adipate terephthalate is particularly preferable.

  Aliphatic aromatic polyesters mainly composed of diol and dicarboxylic acid are obtained by known methods (methods described in JP 2008-31457 A, JP 2008-31456 A, JP 2001-26643 A, etc.). Can be manufactured. For example, a general method of melt polymerization in which after the esterification reaction and / or transesterification reaction of the above aliphatic dicarboxylic acid, aromatic dicarboxylic acid and aliphatic diol, a polycondensation reaction is performed under reduced pressure Alternatively, it can also be produced by a known solution heating dehydration condensation method using an organic solvent, but from the viewpoint of economy and simplicity of the production process, a method of production by melt polymerization carried out in the absence of a solvent is preferred.

  Examples of usable products (commercially available products) include polybutylene terephthalate adipate resin Ecoflex manufactured by BASF.

1.2. Other resins In the present invention, in addition to the aliphatic polyester resin (A), other resins may be included as long as the effects of the present invention are not impaired. Examples of other resins include polyamide, polyvinyl alcohol, cellulose ester, and aromatic polyester.

  In the resin composition of the present invention, the blending ratio of the aliphatic polyester resin (A) and the other resin may be such that the aliphatic polyester resin (A) is a main component in the resin component. Specifically, the total amount of the resin components contained in the resin composition is 100% by mass, and the aliphatic polyester resin (A) is 50% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more.

1.3. Organophosphorus compound (B)
In the present invention, the organophosphorus compound (B) has a chemical structure represented by the following formula (1).

[In the formula (1), X represents a hydrogen atom or OH, n represents an integer of 1 to 20, and m represents 1 or 2.
Indicates. ]

  In the formula (1), X is preferably OH, n is preferably an integer of 2 to 18, more preferably an integer of 4 to 13, and more preferably an integer of 6 to 10.

Further, m is 1 or 2, but the compound represented by the formula (1) does not have to be a single compound having m = 1 and m = 2, and is a compound having m = 1 and m = 2. It may be a mixture of The mixing ratio is not particularly limited, and may be a mixing ratio that inevitably occurs depending on manufacturing conditions and the like. That is, in the formula (1), m is 1 or 2, but it is not necessary to be only one of them.

Examples of the group C _n H _{2n + 1} include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, an isooctyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, and an isodecyl group. , Lauryl group, tridecyl group, oleyl group, stearyl group and the like. Of these, a 2-ethylhexyl group is preferred.

  In the present invention, the organic phosphorus compound (B) contains a phosphate and a phosphite as is apparent from the above formula (1). Further, the phosphate and phosphite may be combined to form diphosphate diphosphite.

  Examples of the organic phosphorus compound represented by the formula (1) include 2-ethylhexyl acid phosphate, bis (2-ethylhexyl) hydrogen phosphite, ethyl acid phosphate, butyl acid phosphate, isotridecyl acid phosphate, oleyl acid phosphate, Examples thereof include diethyl hydrogen phosphite, bis (2-ethylhexyl) hydrogen phosphite, dilauryl hydrogen phosphite, and dioleyl hydrogen phosphite. Among these, 2-ethylhexyl acid phosphate, bis (2-ethylhexyl) hydrogen phosphite, isotridecyl acid phosphate, dilauryl hydrogen phosphite are preferable, and 2-ethylhexyl acid phosphate, bis (2-ethylhexyl) hydrogen phosphite. Is more preferable. These compounds may be used individually by 1 type, or may be used 2 or more types by arbitrary ratios and combinations.

  In the resin composition of the present invention, the lower limit of the content of the organophosphorus compound (B) is 0.3 parts by mass or more, preferably 0.5 parts by mass or more with respect to 100 parts by mass of the aliphatic polyester resin (A). More preferably 0.6 parts by mass or more, still more preferably 0.8 parts by mass or more, particularly preferably 1.5 parts by mass or more, and the upper limit is 5 parts by mass or less, preferably 4.8 parts by mass or less. Preferably it is 4.0 mass parts or less, More preferably, it is 3.5 mass parts or less, Most preferably, it is 3.0 mass parts or less.

  In the present invention, the organophosphorus compound has a function as a hydrolysis accelerator for the aliphatic polyester resin. By blending the above-mentioned aliphatic polyester resin (A) with the organophosphorus compound (B) so as to have the above content, it has a sufficient molecular weight (intrinsic viscosity) at the time of production, and is humid in soil and water. It is possible to obtain an aliphatic polyester resin composition having characteristics that cause degradation under controlled conditions, that is, a molecular weight that rapidly decreases even under mild temperature conditions.

1.4. Other components The resin composition of the present invention includes various kinds of lubricants, fillers (fillers), plasticizers, antistatic agents, antioxidants, light stabilizers, ultraviolet absorbers, dyes, pigments, hydrolysis inhibitors, and the like. Additives, animal / plant substance fine powders such as starch, cellulose, paper, wood powder, chitin / chitosan, coconut shell powder, walnut shell powder, or a mixture thereof may be included as "other ingredients" Good. These can be arbitrarily used as long as the effects of the present invention are not impaired. These may be used individually by 1 type, or may be used 2 or more types by arbitrary ratios and combinations. As other components, known additives can be used without any particular limitation. The added amount of other components is usually such that the total amount of compounds to be mixed is 0.01% by mass or more and 40% by mass or less with respect to the total amount of the resin composition so as not to impair the physical properties of the resin composition. Is preferred.

1.4.1. Lubricant When the resin composition of the present invention contains a lubricant, the moldability of the resin composition can be improved.

Examples of the lubricant include paraffins such as paraffin oil and solid paraffin; higher fatty acids such as stearic acid and palmitic acid; higher alcohols such as palmityl alcohol and stearyl alcohol; calcium stearate, zinc stearate, barium stearate, aluminum stearate , Metal salts of fatty acids such as magnesium stearate and sodium palmitate; fatty acid esters such as butyl stearate, glycerin monostearate, diethylene glycol monostearate; stearamide, methylenebisstearamide, ethylenebisstearamide, oxystearic acid Fatty acid amides such as ethylenediamide, methylolamide, oleylamide, stearic acid amide, erucic acid amide; carnauba wax, montan wax, etc. Waxes, and the like. Of these, erucic acid amide is particularly preferred. In addition, lubricants and waxes may be used alone or in combination of two or more in any ratio and combination. The content of these lubricants is usually in the range of 0.01 to 2% by mass and preferably in the range of 0.05 to 0.5% by mass in the resin composition.

1.4.2. Filler When a filler is included in the resin composition of the present invention, the rigidity of the resin composition can be improved. Moreover, when a resin composition is used as a film, blocking between films can be prevented. Alternatively, when the film is formed into a bag, the opening of the bag can be easily opened. Furthermore, the film and the bag can be colored to improve the light shielding property and the light reflecting property.

Depending on the shape of the filler, there are fibrous, powdery, and plate-like fillers, and powdery and plate-like fillers are particularly preferable. Examples of the particulate filler include mineral particles such as talc, zeolite, diatomaceous earth, kaolin, clay, silica and quartz powder; metal carbonate particles such as calcium carbonate, magnesium carbonate and heavy calcium carbonate; calcium silicate and aluminum silicate Metal silicate particles such as magnesium silicate; metal oxide particles such as alumina, silica, zinc oxide and titanium oxide; metal hydroxide particles such as aluminum hydroxide, calcium hydroxide and magnesium hydroxide; carbon such as carbon black Particles and the like. Moreover, as a plate-shaped filler, mica is mentioned, for example. From the viewpoint of facilitating the opening of the bag and preventing blocking, talc, calcium carbonate, or silica is preferably used. From the viewpoint of coloring the film or bag and improving the light shielding property or light reflecting property. Carbon black or titanium oxide may be used. The dispersion state of the filler in a molded body such as a film or the resin composition is 0.08 to 25 μm, more preferably 0.1 to 5 μm, in terms of number average particle diameter. When it deviates from this range, the addition effect of the said filler will become low. A filler may be used individually by 1 type, or may be used 2 or more types by arbitrary ratios and combinations. These fillers are usually used in the resin composition in the range of 0.05 to 40% by mass.

1.4.3. Plasticizer In addition, when the flowability of a resin composition is bad, it is good to add a plasticizer. In particular, when a filler is included in the resin composition, the viscosity of the resin composition may increase and the flowability of the resin composition may deteriorate, and this may be reduced by adding a plasticizer to the resin composition. Can be improved.

Examples of the plasticizer include methyl adipate, diethyl adipate, diisopropyl adipate, di-n-propyl adipate, di-2-ethylhexyl adipate, diisobutyl adipate, dibutyl adipate, diisodecyl adipate, dibutyl diglycol adipate, di-2-ethylhexylase Fatty acid esters such as rate, dibutyl sebacate, di-2-ethylhexyl sebacate, methylacetyl lysylate; glycerin esters such as triacetin; diethyl maleate, dibutyl maleate, dioctyl maleate, dibutyl fumarate, dioctyl fumarate, etc. Maleic acid and fumaric acid ester; polyester / epoxidized ester such as adipic acid-1,3-butylene glycol and epoxidized soybean oil; trioctyl Trimellitic acid esters such as melitrate; triethylene glycol diacetate, tributyl acetyl citrate, glycerol diacetomonopropionate, glycerol diacetomonocaprylate, glycerol diacetomonocaprate, glycerol diacetomonolaurate, glycerol diacetomonooleate, glycerol Acetylated monoglycerides such as monoacetomonobehenate and glycerin monoacetomonostearate; polyglycerides such as diglycerin acetate, decaglycerin propionate, tetraglycerin caprylate, decaglycerin laurate, decaglycerin oleate, decaglycerin behenate Examples include glycerin fatty acid esters; rosin derivatives and the like. These plasticizers may be used alone or in combination of two or more in any ratio and combination. The plasticizer is preferably used in the resin composition in the range of 0.05 to 10% by mass.

1.4.4. Antistatic agent The resin composition of the present invention may contain an antistatic agent. Any antistatic agent can be used as long as the effects of the present invention are not significantly impaired. Specific examples include surfactant type nonionic, cationic and anionic types.

  Nonionic antistatic agents include, for example, glycerin fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, alkyl diethanolamine, hydroxyalkyl monoethanolamine, polyoxyethylene alkylamine, polyoxyethylene alkylamine fatty acid ester , Alkyldiethanolamide and the like. Of these, alkyldiethanolamine is preferred.

  Examples of the cationic antistatic agent include tetraalkylammonium salts and trialkylbenzylammonium salts.

  Examples of the anionic antistatic agent include alkyl sulfonates, alkyl benzene sulfonates, and alkyl phosphates. Of these, alkylbenzene sulfonate is preferable. This is because the kneadability with the resin is good and the antistatic effect is high.

  The amount of the antistatic agent used is arbitrary as long as the effects of the present invention are not significantly impaired. However, the lower limit of the resin composition is preferably 0.5% by mass or more, more preferably 1% by mass or more, and the upper limit. Is preferably 5% by mass or less, more preferably 3% by mass or less. When the above range is exceeded, the resin composition has surface stickiness and the product value tends to decrease. On the other hand, if it is below the above range, the effect of improving the antistatic property tends to be reduced.

1.4.5. Other Additives In addition to the above additives, the resin composition of the present invention may contain starch, a light-resistant agent, an ultraviolet absorber, a heat stabilizer, a terminal blocking agent, and the like.

  Examples of the starch include corn starch, waxy corn starch, high amylose corn starch, wheat starch, rice starch, potato starch, sweet potato starch, tapioca starch, and pea starch. These can be used as unmodified products or modified products. Modification includes all modification methods such as chemical, physical, and biological, and chemical modification includes esterification, etherification, oxidation, reduction, or partial or all of the structural units of carbohydrates (polysaccharides). It shows that it is modified by a chemical reaction such as coupling, dehydration, hydrolysis, dehydrogenation, halogenation, etc., and particularly shows that a hydroxyl group is etherified or esterified. Physical modification means changing physical properties such as changing the crystallinity. Biological degeneration refers to changing a chemical structure or the like using a living organism.

Examples of the light stabilizer include bis (2,2,6,6-tetramethyl-1 (octyloxy) -4-piperidinyl) ester decanoate, a reaction product of 1,1-dimethylethyl hydroperoxide and octane, Bis (1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butyl malonate, bis (1,2 , 2,6,6-pentamethyl-4-piperidyl) sebacate, methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) ) Sebacate, 1- [2- [3- [3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di-ter -Butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperidine, poly [[6- (1,1,3,3-tetramethylbutyl) amino-1,3,5- Triazine-2,4-diyl] [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}] and the like Hindered amine stabilizers and the like. The light stabilizer is preferably used in combination with an ultraviolet absorber, and a combination of a hindered amine stabilizer and an ultraviolet absorber is effective.

  The amount of the light proofing agent to be mixed is, on the mass basis, preferably 100 ppm or more, more preferably 200 ppm or more, and the upper limit is preferably 5% or less, more preferably 1% or less, based on the resin composition. Preferably it is 0.5% or less. Below this range, the effect of the light resisting agent tends to be small. Moreover, when it exceeds this range, the manufacturing cost tends to increase, and the heat resistance of the resin composition tends to be inferior, or the light-proofing agent tends to bleed out.

  Examples of the ultraviolet absorber include 2- (2H-benzotriazol-2-yl) -4-6-bis (1-methyl-1-phenylethyl) phenol, 2- (4,6-diphenyl-1,3). , 5-triazin-2-yl) -5-[(hexyl) oxy] phenol and the like. It is preferable to use two or more different kinds of ultraviolet absorbers in any ratio and combination.

  The amount of the ultraviolet absorber to be mixed is arbitrary as long as the effects of the present invention are not significantly impaired. However, the lower limit of the resin composition is preferably 100 ppm or more, more preferably 200 ppm or more, and the upper limit. Is preferably 5% or less, more preferably 2% or less, and still more preferably 0.5% or less. Below this range, the effect of the ultraviolet absorber tends to decrease. Moreover, when it exceeds this range, the production cost tends to be too high, the heat resistance of the resin composition is inferior, or the ultraviolet absorber bleeds out.

  Examples of the heat stabilizer include dibutylhydroxytoluene (BHT; 2,6-di-tert-butyl-4-methylphenol), 2,2′-methylenebis (4-methyl-6-tert-butylphenol), pentaerythritol. Tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl-a, a ′, a ″-(mesitylene-2,4,6-triyl) tri-p-cresol, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-tris [ (4-tert-Butyl-3-hydroxy-2,6-xylyl) methyl] -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3 5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, calcium diethylbis [[3 5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] phosphonate, bis (2,2′-dihydroxy-3,3′-di-tert-butyl-5,5′-dimethylphenyl) ethane Hindered phenol heat stabilizers such as N, N′-hexane-1,6-diylbis [3- (3,5-di-tert-butyl-4-hydroxyphenylpropionamide; 3-hydroxy-5,7 -Lactone heat stabilizers such as di-tert-butyl-furan-2-one and xylene reactive organisms; dilauryl thiodipropionate, distearyl thiodipropionate Sulfur-based antioxidants and the like can be mentioned. Alternatively, the organic phosphorus compounds described above by (B), it is also possible to also functions as a phosphorus-based heat stabilizer.

  The amount of the heat stabilizer to be mixed is based on the mass of the resin composition, and the lower limit is preferably 100 ppm or more, more preferably 200 ppm or more, and the upper limit is preferably 5% or less, more preferably 1% or less. More preferably, it is 0.5% or less. Below this range, the effect of the heat stabilizer tends to be small. On the other hand, if it exceeds this range, the manufacturing cost tends to be high, and the bleedout of the thermal stabilizer may occur.

  The end-capping agent is mainly used for the purpose of suppressing hydrolysis due to moisture in the atmosphere, and examples thereof include carbodiimide compounds, epoxy compounds, and oxazoline compounds. Among the above carbodiimide compounds, examples of the monocarbodiimide compound include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, di-t-butylcarbodiimide, di-β- Naphthyl carbodiimide etc. are mentioned. Of these, dicyclohexylcarbodiimide and diisopropylcarbodiimide are preferred because they are easily available industrially.

  Examples of the polycarbodiimide compound include U.S. Pat. No. 2,941,956, Japanese Patent Publication No. 47-33279, J. Pat. Org. Chem. 28, p2069-2075 (1963), Chemical Review 1981, 81, No. 4, p. What was manufactured by the method described in 619-621 grade | etc., Can be used.

  These carbodiimide compounds may be used individually by 1 type, or may be used 2 or more types by arbitrary ratios and combinations. In the present invention, it is particularly preferable to use a polycarbodiimide compound, and the degree of polymerization of the lower limit is usually 2 or more, preferably 4 or more, and the upper limit is usually 40 or less, preferably 20 or less. The amount of these carbodiimides is usually 0.1 to 5% by mass with respect to the entire resin composition.

  In addition to these, known surface wettability improvers, flame retardants, mold release agents, incineration aids, pigments, dispersion aids, surfactants, hydrolysis inhibitors, crystal nucleating agents, compatibilizing agents and the like are included. Also good.

2. Properties of Aliphatic Polyester Resin Composition The resin composition of the present invention preferably has an intrinsic viscosity (IV) of 0.6 to 1.8. The intrinsic viscosity is more preferably 0.8 or more, further preferably 1.0 or more, more preferably 1.6 or less, and further preferably 1.4 or less. If the intrinsic viscosity is too small, the mechanical properties of the molded product may be lowered. If the intrinsic viscosity is too large, the melt viscosity becomes too high during molding and the moldability may be lowered.

  In addition, in the resin composition of the present invention, the intrinsic viscosity retention rate with respect to the aliphatic polyester resin (A) as a raw material is preferably 60% or more and 100% or less, and more preferably 80% or more and 100% or less. preferable. If the intrinsic viscosity retention is less than 60%, a large amount of low molecular weight components derived from the aliphatic polyester resin composition are produced, and thus trouble may occur during molding of the resin composition.

  Moreover, the intrinsic viscosity retention after water immersion becomes a predetermined preferable range by containing the organophosphorus compound (B) as described above in the resin composition of the present invention. That is, the resin composition of the present invention preferably has an intrinsic viscosity retention of 20% or less after being immersed in water at 60 ° C. for 13 days. The intrinsic viscosity retention is more preferably 15% or less, and still more preferably 12% or less. Thereby, since molecular weight falls rapidly, it can be used conveniently for the use as which quick decomposition | disassembly is calculated | required.

The resin composition of the present invention has a mass retention of 90 after being immersed in 60 ° C. water for 13 days.
% Or less is preferable. The mass retention rate is more preferably 85% or less, and still more preferably 80% or less. Thereby, it can use suitably for the use for which quick decomposition | disassembly is calculated | required.

3. Production method of aliphatic polyester resin composition The resin composition of the present invention is an organophosphorus compound (B) of 0.3 to 5 represented by the formula (1) with respect to 100 parts by mass of the aliphatic polyester resin (A). The mass part can be produced by further melt-kneading other components as necessary using an extruder. Here, the details of the aliphatic polyester resin (A), the organic phosphorus compound (B), and other components used as raw materials are the same as described above.

  In the prior art, an organic phosphorus compound (for example, a phosphorus-based antioxidant or a heat stabilizer) is mixed (internal polymerization) with a raw material at the time of polymerizing a resin. If too much is added, polymerization is inhibited. Moreover, the molecular weight of the resin to be produced is lowered, which is not preferable as a polymer. On the other hand, in the present invention, after polymerizing the polymer in advance, the polymer (aliphatic polyester resin (A)) and the organophosphorus compound (B) are characterized by melting and kneading, It has a sufficient molecular weight at the time of production, excellent mechanical properties, and a large amount of organophosphorus compound is added than before, so that after production, the molecular weight rapidly decreases under high humidity conditions such as in soil and water. The resin composition which has the outstanding effect which is not before can be obtained.

  In addition, when melt-kneading the aliphatic polyester resin (A) and the organophosphorus compound (B), it is preferable that the water content in the aliphatic polyester resin (A) before kneading is within a predetermined range. In other words, the upper limit of the amount of water in the aliphatic polyester resin (A) before melt-kneading is preferably 2000 ppm or less, more preferably 1500 ppm or less, on a mass basis. Thereby, the intrinsic viscosity retention with respect to the aliphatic polyester resin (A) of the aliphatic polyester resin composition obtained by melt-kneading the aliphatic polyester resin (A) and the organic phosphorus compound (B) is 60% or more. It is easier to maintain. The lower limit of the moisture content is not particularly limited, and the lower the moisture content, the better.

  In the production of the resin composition, all conventionally known mixing / kneading techniques can be applied. As the mixer, a horizontal cylindrical type, V-shaped, double-cone type mixer, a blender such as a ribbon blender or a super mixer, various continuous mixers, or the like can be used. As the kneader, a batch kneader such as a roll or an internal mixer, a single-stage or two-stage continuous kneader, a twin screw extruder, a single screw extruder, or the like can be used. In this invention, it is preferable to use a twin screw extruder from the point of kneading | mixing efficiency, and also the thing whose rotation direction of a screw is the same direction is preferable.

  Specific examples of the production method include a method in which the aliphatic polyester resin (A), the organophosphorus compound (B), and other components as necessary are blended and then melt mixed in the same extruder. Alternatively, the aliphatic polyester resin (A) and the organic phosphorus compound (B) can be mixed and heated and melted, and other components can be added and blended as necessary. At this time, blending oil or the like can be used for the purpose of uniformly dispersing the respective components.

A single screw or twin screw extruder can be used as the resin extruder. In particular, it is preferable to use a resin extruder equipped with a vacuum vent and perform melt kneading while reducing the pressure inside the extruder with the vacuum vent. The internal pressure of the extruder during decompression is preferably about 5 to 50 kPa. By reducing the pressure in the system at the time of melt-kneading, moisture can be removed from the resin composition, and a resin composition having further excellent mechanical properties and the like can be obtained.
Moreover, conditions, such as temperature at the time of melt-kneading and screw rotation speed, are not specifically limited, What is necessary is just to apply conventionally well-known conditions.

4). Resin molded product and use The method for obtaining the molded product from the resin composition of the present invention is not particularly limited, and various molding methods employed for thermoplastic resins can be applied. Examples of the obtained molded products include molded products by injection molding methods such as injection molding, injection blow molding, injection compression molding, and foam molding; pipes and tubes by extrusion molding methods such as T-die method, inflation method, and laminating. , Shaped products such as wire-covered, multi-layer or single-layer film / sheet, monofilament, multifilament, core-sheath structure fiber; molded product by blow molding method, molded product by vacuum molding method, molded product by calendar molding method Examples thereof include a molded product by a compression molding method and a molded product such as a powder or a granule by a pulverization method.

  In the present invention, the resin composition of the present invention is molded into a molded product by directly performing melt-kneading of the aliphatic polyester (A) and the organophosphorus compound (B) with a molding machine used in the molding method described above. Can also be manufactured directly.

  The resin composition of the present invention has good mechanical strength at the initial stage of use, and rapidly decreases in molecular weight under high humidity conditions such as in soil and water. In order to effectively use the characteristics, the resin composition of the present invention is preferably formed into a film, container, fiber, particle or the like used for agricultural use, soil reforming, underground resource extraction such as crude oil or gas, and the like. . When forming into a film, it is also possible to set it as the laminated | multilayer film which laminated | stacked several types of compositions in the range which does not inhibit the effect of this invention. When the resin composition of the present invention is formed into a film, the film may be uniaxially or biaxially stretched by a roll method, a tenter method, a tubular method, or the like. When extending | stretching, extending | stretching temperature is normally in the range of 30 to 110 degreeC, and a draw ratio is performed in the range of 0.6 to 10 times in the vertical and horizontal directions, respectively. Further, after stretching, heat treatment may be performed by a method of blowing hot air, a method of irradiating infrared rays, a method of irradiating microwaves, a method of contacting on a heat roll, or the like.

  The resin composition of the present invention has sufficient mechanical strength at the initial stage of use as specifically shown in the examples described later, and is 100 ° C. or lower, and further 70 ° C. or lower in water or soil ( Controlled decomposition characteristics even under mild temperature conditions or cold conditions), ie rapid mass loss, so use with proppant as a sealant for voids when mining underground resources such as crude oil and gas, eg shale gas mining Thus, shale gas mining efficiency can be improved, and contamination of the water source can be prevented.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. In addition, the following examples are shown in order to explain the present invention in detail, and the present invention is not limited to the following examples unless it is contrary to the gist thereof. In addition, various production conditions and evaluation result values in the following examples have meanings as preferred values of the upper limit or the lower limit in the embodiment of the present invention, and the preferred range is the value of the upper limit or the lower limit. It may be a range defined by a combination of values of the examples or values between the examples.

<Evaluation methods and materials>
(1) Underwater decomposition (hydrolysis) test 5.0 g of aliphatic polyester resin composition and 15.0 g of deionized water were placed in a glass bottle, capped, and then placed in an oven at 60 ° C for 13 days. Then, the resin composition was taken out from the glass bottle and dried at 70 ° C. for 6 hours under a nitrogen flow. The obtained resin composition is subjected to mass measurement and intrinsic viscosity measurement, and the ratio between the mass before measurement and the intrinsic viscosity is calculated, and the mass retention rate and intrinsic viscosity retention rate in the underwater decomposition test are calculated. did.

(2) Mass measurement Mass measurement is made by sartorius digital balance A200S (weighing up to 0.0001 g)
It was performed using.

(3) Intrinsic viscosity measurement (IV measurement)
It calculated | required in the following way using the Ubbelohde type viscometer. That is, a mixed solvent of phenol / tetrachloroethane (mass ratio 1/1) was used, and at 30 ° C., the polyester sample solution having a concentration of 0.5 g / dL and the falling seconds of the solvent alone were measured, and the following formula (A )
IV = ((1 + 4KHη _sp ) ^0.5 −1) / (2KHC) (A)
Here, η _sp = η / η ₀ −1, η is the sample solution dropping time, η ₀ is the solvent dropping time, C is the sample solution concentration (g / dL), and KH is the Huggins constant. It is. KH adopted 0.33.

(4) Aliphatic polyester resin The aliphatic polyester resin used is as follows.
(PBS-1) Polybutylene succinate manufactured by Mitsubishi Chemical Corporation FZ61PN, IV = 1.228
(PBS-2) Polybutylene succinate FZ71PN, IV = 1.427 manufactured by Mitsubishi Chemical Corporation
(PBSA) manufactured by Mitsubishi Chemical Co., Ltd. Polybutylene succinate adipate FD92WN, IV = 1.752
(PLA) Polylactic acid 6302D, IV = 1.383 manufactured by Nature Works

(5) Hydrolysis accelerator The additives used as the hydrolysis accelerator are as follows.
(2-ethylhexyl acid phosphate) JP-508 manufactured by Johoku Chemical Industry Co., Ltd.
(Bis (2-ethylhexyl) hydrogen phosphite) JPE-208 manufactured by Johoku Chemical Industry Co., Ltd.
(Tris (2-ethylhexyl) phosphate) Reagent made by Tokyo Chemical Industry Co., Ltd. Tris (2-ethylhexyl) Phosphate
(Triphenyl Phosphate) Reagent made by Tokyo Chemical Industry Co., Ltd. Triphenyl Phosphate
(Trilauryl phosphite) Johoku Chemical Industry Co., Ltd. JP-312L
(Dialkylpentaerythritol phosphite) PEP-4C manufactured by ADEKA
(Phosphate) Reagent manufactured by Wako Pure Chemical Industries, Ltd. Phosphoric acid

<Production and Evaluation of Aliphatic Polyester Resin Composition>
[Examples 1-6, Comparative Examples 1-8]
Aliphatic polyester resin and hydrolysis accelerator are melted in a twin-screw extruder (TEX30; 15 cylinders, L / D = 52.5) manufactured by Nippon Steel Works having one vent port in the ratio shown in Table 1. After kneading and extruding in a strand form from the outlet of the twin-screw extruder, cooling and solidifying with water, the mixture was pelletized with a rotary cutter to obtain an aliphatic polyester resin composition. The set temperature during kneading was 140 ° C., and the screw rotation speed was 300 rpm.
The obtained aliphatic polyester resin composition was subjected to an underwater decomposition (hydrolysis) test, and the respective retention rates were calculated from the mass and intrinsic viscosity measured before and after the test. The results are shown in Table 1.

In addition, IV before kneading | mixing in Example 6 was computed from the following formula.
Before kneading IV = (IV of PBS-2) × 0.92 + (IV of PLA) × 0.08

  In each of Examples 1 to 6, the intrinsic viscosity retention after kneading is 60% or more, and the intrinsic viscosity retention in an underwater decomposition (hydrolysis) test (at 60 ° C. after 13 days) is 20% or less. , When used as a sealant for voids in mining underground resources such as crude oil and gas, such as shale gas mining, the proppant solution can be efficiently put into the shale layer and decomposed quickly after being put into the ground. It is thought that the pollution of the water source can be prevented. Therefore, it is considered that the material shown in the present invention can be used very suitably in the application.

  The aliphatic polyester resin composition of the present invention has sufficient mechanical strength at the time of manufacture and at the beginning of use, has decomposition characteristics controlled under humid conditions such as soil and water, and rapidly decreases in molecular weight. Wake up. Therefore, for film, sheet, fiber, particle, molded product, etc., for applications that require rapid degradation after use, such as agricultural applications, soil modification applications, and underground resource mining applications such as oil and gas. Can be widely used.

Claims (9)

A resin composition containing an aliphatic polyester resin (A) and an organophosphorus compound (B) represented by the following formula (1), the organophosphorus compound (B) per 100 parts by mass of the aliphatic polyester resin (A) ) Is 0.3 to 5 parts by mass, an aliphatic polyester resin composition.

(In the formula, X represents a hydrogen atom or OH, n represents an integer of 1 to 20, and m represents 1 or 2.)   The aliphatic polyester resin (A) contains an aliphatic polyester mainly composed of diol and dicarboxylic acid, and the content thereof is 50 to 100 when the entire aliphatic polyester resin (A) is 100 parts by mass. It is a mass part, The aliphatic polyester resin composition of Claim 1 characterized by the above-mentioned.   The aliphatic polyester resin composition according to claim 2, wherein the diol is 1,4-butanediol and the dicarboxylic acid is succinic acid.   The aliphatic polyester resin composition according to any one of claims 1 to 3, wherein the intrinsic viscosity (IV) of the aliphatic polyester resin (A) as a raw material is 0.6 to 1.8. .   The aliphatic polyester resin (A) contains an aliphatic polyester containing oxycarboxylic acid as a main component, and the content thereof is 1 to 50 parts by mass when the entire aliphatic polyester resin (A) is 100 parts by mass. The aliphatic polyester resin composition according to any one of claims 1 to 4, wherein the composition is an aliphatic polyester resin composition.   The aliphatic polyester resin composition according to any one of claims 1 to 5, wherein the aliphatic polyester resin composition has an intrinsic viscosity (IV) of 0.6 to 1.8.   The aliphatic polyester resin composition according to any one of claims 1 to 6, wherein an intrinsic viscosity retention of the aliphatic polyester resin composition with respect to the aliphatic polyester resin (A) as a raw material is 60 to 100%. Resin composition.   The aliphatic polyester resin composition according to any one of claims 1 to 7, wherein the aliphatic polyester resin composition is used for a gap sealing material for underground resource mining.   In the method for producing a resin composition containing an aliphatic polyester resin (A) and an organophosphorus compound (B), the organic compound represented by the formula (1) with respect to 100 parts by mass of the aliphatic polyester resin (A). A method for producing an aliphatic polyester resin composition, comprising melt-kneading 0.3 to 5 parts by mass of a phosphorus compound (B) using an extruder.