JP2011153275A - Polyester resin, resin composition and molded body using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester resin excellent in mechanical properties and heat resistance with high flexibility. <P>SOLUTION: The polyester is a block copolymer (I) comprising a polylactic acid unit (a) and a polyester unit (b) as main components, and is a stereo complex. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polyester resin excellent in mechanical properties and heat resistance, and a resin composition. More specifically, the present invention relates to a polyester resin containing a polylactic acid unit and a polyester unit, and a part or all of the polylactic acid unit is a stereo complex, and a resin composition.

  In recent years, biodegradable resins and resins using biomass-derived materials have been developed and put into practical use as medical materials or environmentally conscious materials. However, these resins are currently inferior in manufacturing cost, mechanical properties, and thermal properties to conventional general-purpose resins and engineering plastics.

  Among them, poly L-lactic acid, which has been known for a long time and is most widely applied, is hydrolyzed non-enzymatically in the living body, and the degradation product enters the metabolic pathway and is finally released outside the body. It has been used as a medical material such as a drug sustained release material for drug delivery systems (DDS). In recent years, since the raw material is derived from plants, it has attracted attention as a material having an effect of suppressing global warming gas. However, compared to general-purpose resins and physical properties, their applications have been limited in that they have low heat resistance, are brittle in mechanical strength and are easily broken.

  In order to overcome such disadvantages of polylactic acid, various solutions have been studied so far. For example, when a polylactic acid stereocomplex crystal is formed by mixing poly L-lactic acid and poly D-lactic acid, the melting point is remarkably improved (Patent Document 1 and Non-Patent Documents 1 and 2). Therefore, the possibility of application of polylactic acid stereocomplexes to fibers and medical materials has been disclosed. (Patent Document 2, Patent Document 3)

  Also, a method of improving mechanical properties by copolymerizing a soft segment such as polyether with polylactic acid (Patent Document 4), or blocking an aliphatic polyester unit derived from dicarboxylic acid and diol in polylactic acid A method of introducing by copolymerization has been proposed (Patent Document 5). Also disclosed is a method of mixing a polymer impact resistance imparting agent obtained by copolymerizing a polyester unit with polylactic acid (Patent Document 6).

JP-A-61-36321 JP 2007-23393 A International Publication No. 2007/116646 Pamphlet JP-A-11-255873 JP 2004-250663 A JP 2001-335623 A

Macromolecules, 24, 5651, 1991 "Biodegradable polymer" written by Yoshito Tsuji, published by IPC Corporation (first edition on September 30, 1999)

  However, in the above-described stereocomplex of poly L-lactic acid homopolymer and poly D-lactic acid homopolymer, the melting point is improved and the heat resistance is improved, but the mechanical properties are poor due to the brittle nature inherent in polylactic acid. It was often sufficient, and there was a problem in putting it to practical use. Furthermore, there has been a problem that a stereocomplex cannot be obtained if the physical properties are improved by increasing the molecular weight or copolymerization.

  In addition, the polymer obtained by copolymerizing the soft segment with the above-mentioned polylactic acid has improved mechanical properties, but the heat resistance is reduced, and the crystallinity of polylactic acid is reduced by the copolymerization. Decreases. Furthermore, since it does not crystallize depending on the copolymerization ratio, there is a problem that the polymer melts at a glass transition temperature of polylactic acid that is not higher than the melting point of polylactic acid. In addition, there is a problem that the glass transition temperature decreases as the soft segment is copolymerized in order to improve the mechanical properties, and the heat resistance is greatly reduced.

  Furthermore, many random copolymers and block copolymers of polylactic acid have been reported for the purpose of improving various physical properties of polylactic acid, but flexible lactic acid polymers having higher heat resistance than polylactic acid homopolymers have been reported. There is no example, and it has been common knowledge that polylactic acid copolymers have lower heat resistance than conventional polylactic acid homopolymers.

  In view of the above, an object of the present invention is to provide a polyester resin containing a polylactic acid unit and a resin composition, which are excellent in heat resistance and excellent in mechanical properties.

  The present inventors have found that the mechanical properties of polylactic acid can be improved by copolymerizing a polyester unit as a soft segment with polylactic acid. In addition, by making the copolymerization of the polylactic acid unit and the polyester unit into a block copolymer, it is possible to make a stereocomplex of poly L-lactic acid and poly D-lactic acid at the polylactic acid part, and it has excellent heat resistance, The inventors have found that a polyester resin excellent in mechanical properties can be obtained, and have reached the present invention.

That is, the gist of the present invention is as follows.
(1) A polyester resin which is a block copolymer (I) mainly composed of a polylactic acid unit (a) and a polyester unit (b), and is a stereocomplex.

(2) The polyester resin according to (1), wherein a melting point derived from the stereocomplex of the polyester resin is 180 ° C. or higher.
(3) The polyester resin according to (1) or (2), wherein the block copolymer (I) is a triblock copolymer.
(4) The polyester resin according to (1) or (2), wherein the block copolymer (I) is a pentablock copolymer.

(5) The polyester resin according to any one of (1) to (4), wherein the polyester unit (b) is an aliphatic polyester unit.
(6) The polyester resin according to any one of (1) to (5), wherein the polyester unit (b) comprises an aliphatic dicarboxylic acid and an aliphatic diol.

(7) Resin composition comprising two or more types of polyester resins which are block copolymers (I) mainly composed of polylactic acid units (a) and polyester units (b), and is a stereocomplex. object.

(8) The resin composition according to (7), wherein a melting point derived from the stereocomplex of the resin composition is 180 ° C. or higher.
(9) The resin composition according to (7) or (8), wherein the block copolymer (I) is a triblock copolymer.

(10) The resin composition according to (7) or (8), wherein the block copolymer (I) is a pentablock copolymer.
(11) The resin composition according to any one of (7) to (10), wherein the polyester unit (b) is an aliphatic polyester unit.
(12) The resin composition according to any one of (7) to (11), wherein the polyester unit (b) comprises an aliphatic dicarboxylic acid and an aliphatic diol.
(13) A molded article comprising the polyester resin according to any one of (1) to (6) or the resin composition according to any one of (7) to (12).

  According to the present invention, it is possible to provide a polyester resin (polylactic acid copolymer) and a resin composition having a high melting point and excellent flexibility and mechanical properties.

The X-ray-diffraction figure of the resin composition of Examples 6-8 is shown.

  Below, the typical aspect for implementing this invention is demonstrated concretely, However, This invention is not limited to the following aspects, unless the summary is exceeded.

A. Polyester resin The polyester resin of the present invention will be described. The polyester resin of the present invention is a block copolymer (I) mainly composed of a polylactic acid unit (a) and a polyester unit (b), and is characterized by being a stereocomplex.

  The block copolymer (I) mainly composed of the polylactic acid unit (a) and the polyester unit (b) in the present invention refers to the polylactic acid unit (a) and the polyester unit (in the block copolymer (I)). The total amount of b) shall mean block copolymer (I) which is 50 weight% or more with respect to the weight of block copolymer (I).

Moreover, the polyester resin being a stereo complex means that part or all of the polylactic acid unit is a stereo complex.
In general, a polylactic acid stereocomplex is formed, for example, by mixing poly-L-lactic acid and poly-D-lactic acid in a solution or in a molten state, as described in Non-Patent Document 2 above, By using a stereo complex, the melting point is higher than that of a homopolymer. As described in Patent Document 1, homopoly L-lactic acid or homopoly D-lactic acid has a peak around 2θ = 16 ° by X-ray diffraction, and stereocomplex polylactic acid has a peak around 2θ = 12 °. Is observed.
In the present invention, by including a poly L-lactic acid unit and a poly D-lactic acid unit in the polyester resin (block copolymer (I)), a part of the poly L-lactic acid unit and the poly D-lactic acid unit. Or it can be set as the polyester resin which all are stereocomplexes. Confirmation that the polyester resin is a stereocomplex can be performed by the above-mentioned X-ray diffraction, melting point measurement described later, and the like.

In the present invention, since the polylactic acid portion is a stereo complex, the heat resistance of the polyester resin can be increased.
In addition, since the block copolymerization is performed using the polyester unit (b) as a soft segment, the mechanical properties can be improved as compared with the case where only the polylactic acid unit is used, and the mechanical properties of the entire polyester resin. Can be made good.

<Polylactic acid unit (a)>
The polylactic acid unit referred to in the present invention is a constituent component having a lactic acid polymer structure obtained by polycondensation or ring-opening polymerization using lactic acid, lactide, or a derivative thereof as a monomer. The unit is 80% by weight or more. Lactic acid used as a monomer includes L-lactic acid and derivatives thereof, D-lactic acid and derivatives thereof, and lactide includes L-lactide and D-lactide. Among these, L-lactide and D-lactide are preferably used as monomers from the viewpoint of polymerizability.

  The polylactic acid unit (a) may be polymerized with a small amount of other copolymer components other than lactic acid or lactide, preferably L-lactic acid, L-lactide, D-lactic acid, D-lactide, or these. One or more of the derivatives is used as a monomer, and its purity is preferably 95% by weight or more, more preferably 98% by weight or more, and further preferably 99% by weight or more. When the purity is smaller than the above value, it is difficult to form a stereo complex, and the heat resistance may be lowered.

The number average molecular weight calculated from ¹ H-NMR of the polylactic acid unit is usually 1,000 or more and 500,000 or less. The lower limit of the number average molecular weight is preferably 2,000, more preferably 5,000, still more preferably 10,000, and particularly preferably 20,000. The upper limit of the number average molecular weight is preferably 200,000, more preferably 100,000, still more preferably 50,000, and particularly preferably 30,000. When the number average molecular weight of the polylactic acid unit is smaller than the lower limit, the melting point derived from the stereocomplex of polylactic acid tends to decrease. Moreover, when larger than the said upper limit, formation of a stereo complex may become difficult and shaping | molding of a polyester resin may become difficult.

<Polyester unit (b)>
As a polyester unit (b), the polyester unit which has an aliphatic polyester unit, an aromatic polyester unit, an aliphatic aromatic polyester unit etc. as a main component is mentioned, for example. These may be used alone or in combination of two or more in any ratio and combination. Here, the main component means that the total amount of the aliphatic polyester unit, the aromatic polyester unit, and the aliphatic aromatic polyester unit is 50% by weight or more based on the weight of the polyester unit (b). .
The polyester unit (b) has a structure derived from a lactic acid monomer of usually 40% by weight or less, preferably 30% by weight or less, more preferably 20% by weight or less. Note that the lactic acid monomer refers to L-lactic acid, L-lactide, D-lactic acid, D-lactide, or derivatives thereof. The amount of the structure derived from the lactic acid monomer in the polyester unit (b) can be measured by NMR.

  The polyester unit (b) is preferably liquid or rubbery or has an elongation percentage of 100% or more when subjected to a tensile test alone, preferably 200% or more, more preferably 300. % Or more. The tensile test is performed by the method specifically shown in the examples.

The aromatic polyester unit is usually a polyester unit composed of an aromatic dicarboxylic acid and an aliphatic diol, and examples thereof include a polyethylene terephthalate unit, a polybutylene terephthalate unit, and a polytrimethylene terephthalate unit.
The aliphatic aromatic polyester unit means a polyester unit composed of an aliphatic dicarboxylic acid, an aromatic dicarboxylic acid and an aliphatic diol, or a polyester unit composed of an aromatic diol and an aliphatic dicarboxylic acid.

  The aliphatic polyester unit is a polyester unit composed of an aliphatic dicarboxylic acid and an aliphatic polyester, or a polyester unit mainly composed of an aliphatic hydroxycarboxylic acid other than lactic acid.

  Among the above, aliphatic polyester units are particularly preferable from the viewpoints of improving the mechanical properties and biodegradability, and easily synthesizing triblock copolymers and pentablock copolymers.

  Moreover, it is preferable that both terminal has a hydroxyl group from the reason that a polyester block (b) can manufacture a triblock copolymer and a pentablock copolymer easily.

  Although the manufacturing method of the polyester unit (b) whose both terminal is a hydroxyl group is not specifically limited, For example, the method of charging many moles of a diol monomer with respect to the moles of a dicarboxylic acid monomer, and synthesize | combining it are used. . The charge ratio between the diol monomer and the dicarboxylic acid monomer varies depending on the molecular weight of the polyester unit (b) to be obtained. The excess is usually 1% or more and 100% or less with respect to the number of moles of the body. The minimum with the preferable excess amount of a diol unit is 5%, More preferably, it is 10%. The upper limit of the excess amount is preferably 50%, more preferably 30%.

The number average molecular weight calculated from ¹ H-NMR of the polyester unit (b) is usually from 3,000 to 500,000. The lower limit of the number average molecular weight is preferably 5,000, more preferably 10,000, still more preferably 15,000, and particularly preferably 20,000. The upper limit of the number average molecular weight is preferably 300,000, more preferably 100,000, still more preferably 60,000, particularly preferably 50,000. By setting the lower limit of the number average molecular weight within the above range, a polyester resin having good mechanical properties and good moldability can be obtained. The higher the number average molecular weight, the better the mechanical properties, but the number average molecular weight that can be produced by a known method is usually 50,000 or less.

  The polyester unit (b) may be polymerized with a small amount of other copolymer components other than the copolymer components such as the dicarboxylic acid and the diol, but the aliphatic polyester unit, the aromatic polyester unit, and the aliphatic The total amount of aromatic polyester units is preferably 60% by weight or more, more preferably 80% by weight or more, and still more preferably 90% by weight or more based on the weight of the polyester unit (b). When the purity is smaller than the above value, it may be difficult to exhibit the characteristics of the polyester unit (b).

Aliphatic dicarboxylic acid Examples of the aliphatic dicarboxylic acid used for the synthesis of the polyester unit (b) include aliphatic dicarboxylic acids having 2 or more carbon atoms, preferably 3 or more, more preferably 4 or more. It is. Moreover, carbon number is 20 or less normally, Preferably it is 12 or less, More preferably, it is 10 or less.

Specific examples include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, heptanedioic acid, octanedioic acid, nonanedioic acid, undecanedioic acid, dodecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecane Examples thereof include diacid, eicosane diacid, maleic acid, fumaric acid, sebacic acid, and derivatives thereof. These can be used individually by 1 type or in mixture of 2 or more types.
Examples of the derivatives include alkyl esters of carboxylic acids, acid chlorides, acid anhydrides, etc. Among them, methyl esters of carboxylic acids are preferable from the viewpoint of reactivity.

  Among the above, succinic acid, adipic acid, sebacic acid and dodecanedioic acid are preferable from the viewpoint of physical properties, succinic acid, adipic acid or a mixture thereof is more preferable, and succinic acid is a substance generated in a Krebs circuit in vivo. Therefore, it is particularly preferable to use it as a biomaterial.

-Aliphatic diol As an aliphatic diol used for the synthesis | combination of a polyester unit (b), carbon number normally has 2 or more aliphatic diol, More preferably, carbon number is 3 or more. Particularly preferably, it is 4 or more. Moreover, carbon number is 20 or less normally, Preferably it is 10 or less, More preferably, it is 8 or less.

  Specific examples include ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentane. Examples thereof include diol, 1,6-hexanediol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol. Among these, 1,4-butanediol, 1,3-propanediol, and 3-methyl-1,5-pentanediol are preferable, particularly 1 from the viewpoint of physical properties and polymerizability of the obtained block copolymer. 4-butanediol and / or 3-methyl-1,5-pentanediol are preferred. These may be used individually by 1 type, and may mix and use 2 or more types.

<Other copolymer components>
The polyester resin of the present invention comprises a polylactic acid unit (a) and a polyester unit (b) as main components. However, the polylactic acid unit (a) or the polyester unit ( b) Or other components may be copolymerized in both units. Raw materials for copolymerizable components include aliphatic hydroxy compounds, aliphatic dicarboxylic acids, aliphatic diols, aromatic dihydroxy compounds, bisphenol, aliphatic (including alicyclic) dicarboxylic acids, aromatic dicarboxylic acids, hydroxycarboxylic acids Examples include acids, diamines, and derivatives thereof. These may be used individually by 1 type, and may mix and use 2 or more types. Among these, aliphatic diols, aliphatic (including alicyclic) dicarboxylic acids and esters thereof, aromatic dicarboxylic acids and esters thereof are preferable, and aliphatic diols are more preferable.

  Specific examples of copolymerizable aliphatic (including alicyclic) dicarboxylic acids include oxalic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, dimer acid, dodecanedioic acid, and 1,6-cyclohexanedicarboxylic acid. Etc. These may be acid anhydrides. Examples of the derivatives of aliphatic (including alicyclic) dicarboxylic acids include lower alkyl esters of these aliphatic (including alicyclic) dicarboxylic acids. Among these, succinic acid, glutaric acid, sebacic acid, dimer acid and dodecanedioic acid, and their lower alkyl (for example, alkyl having 1 to 4 carbon atoms) ester derivatives are preferable, and in particular, lower succinic acid and succinic acid. Alkyl ester derivatives or mixtures thereof are preferred. These may be used individually by 1 type, and may mix and use 2 or more types.

Specific examples of the copolymerizable aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, and the like. 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 and isophthalic acid, and lower alkyl (for example, alkyl having 1 to 4 carbon atoms) ester derivatives thereof are preferable, and methyl ester derivatives of terephthalic acid and terephthalic acid, or a mixture thereof are particularly preferable.
These may be used individually by 1 type, and may mix and use 2 or more types.

Examples of copolymerizable aliphatic and / or alicyclic diols include ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, and 1,5. -Pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, isosorbide and the like. Among these, from the viewpoint of physical properties, 1,4-butanediol, ethylene glycol and 1,3-propanediol are preferable, and 1,4-butanediol and / or ethylene glycol are particularly preferable.
These may be used individually by 1 type, and may mix and use 2 or more types.

The copolymerizable hydroxycarboxylic acid and hydroxycarboxylic acid derivative are not particularly limited as long as they are compounds having one hydroxyl group and carboxyl group in the molecule or derivatives thereof. Specific examples of hydroxycarboxylic acid and derivatives thereof include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 6-hydroxycaproic acid, 2-hydroxy-3,3-dimethylbutyric acid, 2- Examples thereof include hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, mandelic acid, salicylic acid, and esters, acid chlorides, acid anhydrides and the like thereof.
These may be used individually by 1 type, and may mix and use 2 or more types.

  Moreover, when an optical isomer exists in these, any of D-form, L-form, or a racemate may be sufficient.

<Copolymerization ratio of polylactic acid unit (a) and polyester unit (b)>
The copolymerization ratio of the polylactic acid unit (a) and the polyester unit (b) can be arbitrarily set according to the intended use. The copolymerization amount of the polylactic acid unit (a) is usually 1% by weight or more and 99% by weight or less of the entire block copolymer (I). The lower limit of the copolymerization amount of the polylactic acid unit (a) is preferably 5% by weight, more preferably 10% by weight, still more preferably 20% by weight, and particularly preferably 30% by weight. The upper limit of the copolymerization amount of the polylactic acid unit (a) is preferably 95% by weight, more preferably 90% by weight, still more preferably 80% by weight, and particularly preferably 75% by weight. If the polylactic acid unit (a) is less than the lower limit, it is difficult to form a stereocomplex and the heat resistance tends to be lowered. Moreover, when there are more polylactic acid units (a) than the said upper limit, there exists a tendency for a mechanical physical property to fall and to become weak.

  Moreover, the copolymerization amount of the polyester unit (b) is usually 5% by weight or more and 95% by weight or less of the entire block copolymer (I). The lower limit of the copolymerization amount of the polyester unit (b) is preferably 10% by weight, more preferably 15% by weight, still more preferably 20% by weight, and particularly preferably 30% by weight. The upper limit of the copolymerization amount of the polyester unit (b) is preferably 90% by weight, more preferably 85% by weight, still more preferably 80% by weight, and particularly preferably 70% by weight. By setting the polyester unit (b) in the above range, the properties derived from the polyester unit (b) can be exhibited.

  The polyester resin of the present invention (block copolymer (I)) is mainly composed of the polylactic acid unit (a) and the polyester unit (b), and as described above, the polylactic acid unit (a) and The total amount of the polyester unit (b) is 50% by weight or more of the block copolymer (I), more preferably 70% by weight or more, and further preferably 80% by weight or more. These balances are the total amount of other copolymer components and the like.

<Binding format of block copolymer (I)>
The number of polylactic acid units (a) and polyester units (b) in the block copolymer (I) is not particularly limited, but from the viewpoint of ease of formation of a stereocomplex and ease of production, Block copolymers and pentablock copolymers are preferred.

  The triblock copolymer is usually composed of A-C-A, B-C- as bond types, where A is the poly L-lactic acid unit, B is the poly D-lactic acid unit, and C is the polyester unit other than the polylactic acid unit. B, A-C-B, C-A-B, C-A-C, C-B-C, etc. are mentioned. In order to form a stereo complex, both A and B are contained in the same molecule. It is necessary to be included. Therefore, when the polyester resin of the present invention is a triblock copolymer, the bonding type is A-C-B, C-A-B, or A-B-C.

  In the case where the polyester resin of the present invention is a pentablock copolymer, when the poly L-lactic acid unit is A, the poly D-lactic acid unit is B, and the polyester unit is C, the bond type is ABC B-A, B-A-C-A-B, B-A-C-B-A, B-C-A-C-B, A-C-B-C-A and the like can be mentioned. Among these, A—B—C—B—A and B—A—C—A—B are preferable from the viewpoint of ease of production.

<Molecular weight of polyester resin and measuring method thereof>
The number average molecular weight (Mn) of the polyester resin (block copolymer (I)) of the present invention can be calculated from the terminal group quantitative analysis value of the ¹ H-NMR spectrum. The number average molecular weight (Mn) and the weight average molecular weight (Mw) can also be measured by a SEC (Size Exclusion Chromatography) method. Specifically, Mn and Mw can be determined by analyzing a SEC curve based on a calibration curve created from monodisperse standard samples having different molecular weights such as polystyrene or polymethyl methacrylate.

  The number average molecular weight calculated by the SEC of the polyester resin (block copolymer (I)) of the present invention is appropriately selected depending on the use, but is usually 5,000 or more and 500,000 or less. The lower limit of the number average molecular weight is preferably 10,000, more preferably 20,000, still more preferably 40,000, particularly preferably 60,000. The upper limit of the number average molecular weight is preferably 400,000, more preferably 300,000, still more preferably 200,000, and particularly preferably 150,000. If the number average molecular weight is lower than the lower limit, the mechanical properties and melting point may be lowered. Further, if the amount is larger than the above upper limit value, molding may be difficult.

<Melting point derived from stereo complex>
The polyester resin of the present invention preferably has a stereocomplex-derived melting point of 180 ° C. or higher, more preferably 190 ° C. or higher, and further preferably 200 ° C. or higher. When the melting point is lower than 180 ° C., the heat resistance is lowered, and it cannot be applied to applications requiring heat resistance, and the application range is narrowed. The upper limit of the melting point is not particularly limited, but is preferably 280 ° C or lower, more preferably 250 ° C or lower, and further preferably 230 ° C or lower. If the melting point is close to the thermal decomposition temperature, it is necessary to mold at a high temperature during melt molding, and the resin may be decomposed during molding.

  The melting point derived from the stereo complex is a temperature detected by an endothermic peak when the temperature is raised from −50 ° C. to 240 ° C. at 20 ° C./min by a DSC thermal analyzer. When there are a plurality of melting points, the melting point derived from the stereocomplex can be determined by comparing with the melting point of each block copolymer unit or the like and the peak of X-ray diffraction.

<Other ingredients>
The polyester resin (block copolymer (I)) of the present invention may appropriately contain other components in addition to the above polymerization components. Examples of other components include a crosslinking component, a chain extender, and a terminal blocking agent. These may be used alone or in combination of two or more in any ratio and combination.

-Crosslinking component The polyester resin (block copolymer (I)) may contain a small amount of a crosslinking component. Examples of the crosslinking component include a structural unit having a tri- or higher functional ester-forming group, a structural unit having an amide bond-forming group, a structural unit having a urethane bond-forming group, and a structural unit having a carbon-carbon bond. However, from the viewpoint of reactivity, a structural unit having an ester-forming group and a trifunctional compound having a urethane bond-forming group are preferably used.

  The proportion of the crosslinking component is usually 0.01 mol% or more and 30 mol% or less with respect to the total number of moles of the constituent components of the entire block copolymer (I), but the lower limit is preferably 0.05 mol%, more preferably. Is 0.1 mol%, more preferably 0.5 mol%. The upper limit is preferably 10 mol%, more preferably 8 mol%, still more preferably 5 mol%. If the cross-linking component is too small, the cross-linking effect tends to decrease, and if it is too large, molding tends to be difficult.

  Examples of the structural unit compound having a trifunctional or higher functional ester-forming group include a trifunctional or higher polyhydric alcohol; a trifunctional or higher polyvalent carboxylic acid or an anhydride thereof, an acid chloride, an ester; Examples thereof include at least one trifunctional or higher polyfunctional compound selected from the group consisting of hydroxycarboxylic acids or anhydrides, acid chlorides and esters thereof. These may be used individually by 1 type, and may mix and use 2 or more types.

  Examples of the trifunctional or higher functional polyhydric alcohol include glycerin, trimethylolpropane, pentaerythritol and the like. These may be used individually by 1 type, and may mix and use 2 or more types.

  Examples of the tri- or higher functional polycarboxylic acid or anhydride thereof include trimesic acid, propanetricarboxylic acid, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, cyclopentatetracarboxylic anhydride, and the like. Can be mentioned. These may be used individually by 1 type, and may mix and use 2 or more types.

Examples of the tri- or higher functional hydroxycarboxylic acid include malic acid, hydroxyglutaric acid, hydroxymethylglutaric acid, tartaric acid, citric acid, hydroxyisophthalic acid, hydroxyterephthalic acid, and the like. These may be used individually by 1 type, and may mix and use 2 or more types.
Of these, malic acid, tartaric acid, and citric acid are particularly preferred because of their availability.

-Chain extender and terminal blocker In manufacture of block copolymer (I), you may use chain extenders, such as diisocyanate, diphenyl carbonate, dioxazoline, a silicate ester, for example. These may be used individually by 1 type, and may mix and use 2 or more types. In particular, when a carbonate compound such as diphenyl carbonate is used, it is preferable to mix these carbonate compounds in an amount of 20 mol% or less, preferably 10 mol% or less, with respect to all components of the block copolymer (I). .

  In this case, as the carbonate compound, specifically, diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, dimethyl carbonate, diethyl carbonate, dibutyl carbonate, ethylene carbonate, diamyl Examples include carbonate and dicyclohexyl carbonate. In addition, carbonate compounds composed of the same or different hydroxy compounds derived from hydroxy compounds such as phenols and alcohols can also be used.

  Specific examples of the diisocyanate compound include 2,4-tolylene diisocyanate, a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, and 1,5-naphthylene diisocyanate. And known diisocyanates such as xylylene diisocyanate, hydrogenated xylylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.

  Specific examples of the silicate ester include tetramethoxysilane, dimethoxydiphenylsilane, dimethoxydimethylsilane, and diphenyldihydroxylane.

A small amount of peroxide may be mixed to increase the melt tension.
Any of these may be used alone or in combination of two or more.

  Moreover, in this invention, you may seal the polyester terminal group of block copolymer (I) with a carbodiimide, an epoxy compound, monofunctional alcohol, or carboxylic acid.

In this case, examples of the carbodiimide compound of the end-capping agent include compounds having one or more carbodiimide groups in the molecule (including polycarbodiimide compounds). Specifically, the monocarbodiimide compound includes dicyclohexylcarbodiimide, diisopropyl. Carbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, di-t-butylcarbodiimide, di-β-naphthylcarbodiimide, N, N′-di-2,6-diisopropylphenylcarbodiimide, etc. Illustrated.
These may be used individually by 1 type, and may mix and use 2 or more types.

B. Resin Composition The resin composition of the present invention will be described. The resin composition of the present invention contains two or more polyester resins, which are block copolymers (I) having polylactic acid units (a) and polyester units (b) as main components, and is a stereocomplex. And
Here, the term “stereo complex” means that part or all of the polylactic acid unit in the polyester resin is a stereo complex.
In the present invention, the polyester resin containing a poly L-lactic acid unit and the polyester resin containing a poly D-lactic acid unit may be in a stereocomplex, and the poly L-lactic acid unit and the poly D- Lactic acid units are included, and these may be stereocomplexes. Confirmation that the polyester resin in the resin composition is a stereocomplex can be performed by X-ray diffraction, melting point measurement, or the like, as in the case of the polyester resin described above.

  Since the resin composition of the present invention includes a polyester resin in which a part or all of the polylactic acid unit is a stereocomplex, the resin composition can have high heat resistance. It can be set as the resin composition used for.

  Moreover, since the polyester unit (b) is block copolymerized as a soft segment in the polyester resin, the mechanical properties of the polyester resin are improved as compared with the case where only the polylactic acid unit (a) is used. be able to. Therefore, it is possible to use the resin composition for applications that require mechanical properties.

<Polyester resin>
The polyester resin contained in the resin composition of the present invention is not particularly limited as long as it is a polyester resin that is a block copolymer (I) having polylactic acid units (a) and polyester units (b) as main components. However, from the viewpoint of production efficiency and the like, the block copolymer (I) is preferably a triblock copolymer or a pentablock copolymer.

An example of such a polyester resin is the polyester resin described in the section “A. Polyester Resin”. Moreover, the polyester resin contained in the resin composition does not necessarily need to contain a poly L-lactic acid unit and a poly D-lactic acid unit in the block copolymer (I). Therefore, for example, when the block copolymer (I) is a triblock copolymer, the bond form when the poly L-lactic acid unit is A, the poly D-lactic acid unit is B, and the polyester unit is C is: Also included are A-C-A, B-C-B, C-A-C, and C-B-C. In particular, from the viewpoint of production, it is preferable to use ACA or BCB.
In the polyester resin, the polylactic acid unit (a), the polyester unit (b), other copolymerization components, other components, a preferable melting point, and the like are the same as those described in the above section “A. Polyester resin”. can do.

<Content of polyester resin>
The resin composition contains two or more kinds of polyester resins, and the number is not particularly limited as long as the essence of the invention is not impaired, but two kinds are particularly preferable.
The kind of polyester resin to contain is suitably selected according to the use etc. of a resin composition.

  Each polyester resin is preferably contained in the resin composition in an amount of 25% by weight or more, more preferably 40% by weight or more, and further preferably 45% by weight or more. Moreover, it is 75 weight% or less normally, Furthermore, 60 weight% or less, More preferably, it is 55 weight% or less. By setting it as such a range, the function of each polyester resin can be exhibited.

  The total amount of the polyester resin contained in the resin composition is usually 70% by weight or more, preferably 80% by weight or more, and more preferably 90% by weight or more. Moreover, it is 100 weight% or less normally, Preferably it is 98 weight% or less, More preferably, it is 95 weight% or less. By setting it within such a range, the characteristics of the polyester resin can be exhibited, which is suitable for various applications.

<Other ingredients>
The resin composition of the present invention contains additives, crystal nucleating agents, fillers, resins other than the above polyester resins, and the like within a range not impairing the objects and effects of the present invention, in addition to the above two or more types of polyester resins. May be.

Additives The resin composition has various additives such as heat stabilizers, antioxidants, hydrolysis inhibitors, crystal nucleating agents, flame retardants, antistatic agents, mold release, as long as the properties are not impaired. An agent, an ultraviolet absorber or the like may be mixed.

  These additives may be mixed in the reaction apparatus before the polymerization reaction of the polyester resin, or may be mixed in a conveying apparatus or the like from the start of the polymerization reaction to the end of the polymerization reaction. You may mix before extracting a thing. Moreover, you may mix with the product after extraction.

Crystal nucleating agent A crystal nucleating agent may be mixed in the resin composition. As the crystal nucleating agent, talc, boron nitride, silica, layered silicate, polyethylene wax, polypropylene wax are preferable, and talc, Polyethylene wax is preferred. These may be used individually by 1 type, and may mix and use 2 or more types.

  When a crystal nucleating agent is mixed with the polyester resin (block copolymer (I)), it is preferably contained in an amount of 0.001% by weight or more based on the block copolymer (I).

  When the crystal nucleating agent is an inorganic material, the smaller the particle size, the better the nucleating agent effect. The average particle size of the preferred crystal nucleating agent is 5 μm or less, more preferably 3 μm or less, still more preferably 1 μm or less, and particularly preferably 0.5 μm or less. The lower limit of the average particle size of the crystal nucleating agent is 0.1 μm.

  A preferable mixing amount of the crystal nucleating agent is more preferably 0.01% by weight or more, still more preferably 0.1% by weight or more with respect to the block copolymer (I). The upper limit of the amount of the crystal nucleating agent mixed is 30% by weight, more preferably 10% by weight, still more preferably 5% by weight, and particularly preferably 1% by weight. If the mixing amount of the crystal nucleating agent is less than the above lower limit, the effect of promoting crystallization by mixing the crystal nucleating agent cannot be sufficiently obtained, and if it exceeds the above upper limit, the mechanical properties are lowered and the flexibility is increased. Tend to be damaged.

  Even when not mixing for the purpose of functioning as a nucleating agent, other purposes such as inorganic fillers mixed for improving the rigidity of polyester resin, organic stabilizers mixed as a thermal stabilizer, etc. also act as nucleating agents. In addition, inorganic or organic foreign matters mixed in the manufacturing process of the polyester resin or in the molding process can be used as the crystal nucleating agent. Accordingly, the crystal nucleating agent referred to in the present invention corresponds to all inorganic substances and organic substances that are solid at room temperature.

Filler When molding the resin composition, in addition to the various additives shown above, glass fiber, carbon fiber, titanium whisker, mica, talc, boron nitride, CaCO ₃ , TiO ₂ , silica, layered silicate, Crystal nucleating agents such as polyethylene wax and polypropylene wax, reinforcing agents, extenders and the like may be mixed and molded. You may use these individually by 1 type or 2 or more types by arbitrary ratios and combinations.

  In addition, various inorganic or organic fillers may be mixed in the resin composition.

  Inorganic fillers include anhydrous silica, mica, talc, titanium oxide, calcium carbonate, diatomaceous earth, allophane, bentonite, potassium titanate, zeolite, sepiolite, smectite, kaolin, kaolinite, glass, limestone, carbon, wollastonite. , Calcinated perlite, silicates such as calcium silicate and sodium silicate, hydroxides such as aluminum oxide, magnesium carbonate and calcium hydroxide, salts such as ferric carbonate, zinc oxide, iron oxide, aluminum phosphate and barium sulfate Is mentioned. These may be used individually by 1 type, and may mix and use 2 or more types.

  When a resin composition containing an inorganic filler is used, the content of these inorganic fillers in the entire composition is usually 1% by weight or more, preferably 3% by weight or more, more preferably 5% by weight or more. is there. Moreover, it is 80 weight% or less normally, Preferably it is 70 weight% or less, More preferably, it is 60 weight% or less.

  Examples of the organic filler include raw starch, processed starch, pulp, chitin / chitosan, palm shell powder, bamboo powder, bark powder, and powders such as kenaf and straw. These may be used individually by 1 type, and may mix and use 2 or more types.

  When setting it as the resin composition containing an organic type filler, content of these organic type fillers in a resin composition is 0.1 weight% or more normally, Preferably it is 1 weight% or more. Moreover, it is 70 weight% or less normally, Preferably it is 50 weight% or less.

  If the content of the inorganic filler and the organic filler is less than the above lower limit value, the filler mixing amount is small, so that the mixing effect may not be sufficiently obtained. There is a tendency for mechanical properties to decrease, such as impact resistance.

C. Production method of polyester resin and resin composition <Production method of polyester resin>
The manufacturing method of the above-mentioned polyester resin is not particularly limited as long as the above-described polyester resin can be manufactured. For example, a known method relating to the production of a polyester block copolymer can be employed. In particular, a known method for producing a polylactic acid diblock copolymer or a triblock copolymer can be suitably employed.

  Specific examples of the method for producing a polyester resin include a method in which a polyester unit (b) is synthesized, and then a polylactic acid unit (a) is polymerized at one or both ends of the polyester unit (b). After synthesizing the unit (a), a method of polymerizing the polyester unit (b) at one end or both ends of the polylactic acid unit (a) can be used. Hereinafter, a method for polymerizing the polylactic acid unit (a) to the polyester unit after producing the polyelter unit (b) will be described, but the present invention is not limited thereto.

-Synthesis method of polyester unit (b) As a synthesis method of the polyester unit (b) in the polyester resin, a known method relating to the production of polyester can be employed.

Specific examples of the production method include solution polymerization, melt polymerization, interfacial polycondensation, and the like, and melt polymerization is preferable from the viewpoint of efficiency.
In melt polymerization, after the raw materials are usually charged, the reaction vessel is heated and depressurized to carry out an esterification reaction and a polycondensation reaction. The esterification reaction is usually performed at a temperature equal to or higher than the melting point of the raw material at normal pressure or in a nitrogen stream, and the polycondensation reaction is performed under reduced pressure at a temperature equal to or higher than the melting point of the raw material and the produced polymer. The polymerization reaction at this time can set appropriate conditions conventionally employed, and is not particularly limited.

  For example, when the polyester unit (b) is an aliphatic polyester unit, it is preferable to add a component and copolymer component having the above-mentioned aliphatic dicarboxylic acid and aliphatic diol, as well as a chain extender and a terminal blocking agent. And produced in the presence of a catalyst.

  Specific procedures, conditions, and the like of the polymerization step are not particularly limited, and known polyester manufacturing procedures, conditions, and the like can be applied as they are.

(I) Catalyst:
The polymerization step is usually carried out in the presence of a catalyst.
The type of the catalyst is not particularly limited, and any catalyst that can be used for the production of polyester can be selected. Usually, a metal catalyst is used.

  Examples of metal catalysts include germanium, titanium, zirconium, hafnium, antimony, tin, magnesium, calcium, zinc, aluminum, cobalt, lead, cesium, manganese, lithium, potassium, sodium, copper, barium, cadmium, etc. Is mentioned. Any one of these may be used alone, or two or more may be used in any combination and ratio.

  Among these, as the metal catalyst, a tin compound, a germanium compound, a titanium compound, a magnesium compound, a zinc compound, and a lead compound are preferable, a tin compound, a titanium compound, and a magnesium compound are more preferable, and a tin compound is particularly preferable.

  Preferable specific examples of the tin compound include tin octylate, tin chloride, tin oxide and the like. Any one of these may be used alone, or two or more may be used in any combination and ratio. Among these, tin chloride and tin octylate are preferable in terms of high activity, and tin chloride is particularly preferable.

  Preferable specific examples of the titanium compound include organic titanium compounds such as tetraalkoxytitanium such as tetrapropyl titanate, tetrabutyl titanate, tetraethyl titanate, tetrahydroxyethyl titanate, and tetraphenyl titanate. Any one of these may be used alone, or two or more may be used in any combination and ratio. Of these, tetrapropyl titanate and tetrabutyl titanate are preferable, and tetrabutyl titanate is particularly preferable from the viewpoints of price and availability.

  Specific examples of suitable magnesium compounds include magnesium formate, magnesium acetate, magnesium propionate, magnesium n-butyrate, magnesium n-valerate, magnesium n-caproate, magnesium n-caprate, magnesium stearate, magnesium oxide and the like. Is mentioned. Any one of these may be used alone, or two or more may be used in any combination and ratio. Among these, magnesium formate, magnesium acetate, and magnesium propionate are preferable, and magnesium acetate is particularly preferable.

  Among these, a combination of tetraalkoxy titanium and a magnesium compound is preferable from the viewpoint of high catalytic activity, and a combination of tetrabutyl titanate and magnesium acetate is particularly preferable.

  The amount of the catalyst used is a weight ratio in terms of metal in the catalyst with respect to the total weight of all raw materials, and is usually 0.1 ppm or more, preferably 10 ppm or more, more preferably 100 ppm or more, and particularly preferably 500 ppm or more. The amount of the catalyst used is usually 30,000 ppm or less, preferably 20,000 ppm or less, more preferably 10,000 ppm or less, and particularly preferably 5,000 ppm or less. If the amount of catalyst used is too small, the reaction rate of the polymerization reaction becomes too slow, which may be undesirable in production. On the other hand, if the amount of the catalyst used is too large, the produced polyester unit (b) may be colored and the production cost may become too high. In addition, the stability of the polyester unit (b) from which the catalyst residue is obtained may be affected, and when used as a medical material, there may be a problem with safety in vivo.

(Ii) Presence or absence of solvent:
The polymerization step may be performed in the presence of a solvent or may be performed in the absence of a solvent. However, the solvent is removed after the polymerization reaction if the polymerization step is performed under a condition where the solvent is not substantially present. It is preferable because the process can be omitted and the production can be efficiently performed. Here, “under conditions where substantially no solvent is present” means that the amount of the solvent used relative to the raw material is usually 10% by weight or less, preferably 5% by weight or less, more preferably 1% by weight or less, particularly preferably 0.8%. 1% by weight or less. However, even in this case, a small amount of solvent may be used when a catalyst, an additive, or the like is charged during the polymerization reaction.

(Iii) Reaction method:
The reaction system in the polymerization step is not particularly limited, and can be carried out in batch equipment or continuous equipment. For example, when the reaction is performed in a batch facility, the polymerization process is carried out by charging the raw materials using a reactor capable of controlling the internal temperature and pressure, and further adjusting the temperature and pressure in the reactor. Good.

  There are no particular limitations on the timing for charging the catalyst, additives, and the like in the polymerization step. It may be charged simultaneously with the raw material, or may be charged before or after the raw material is charged.

(Iv) Polymerization conditions:
The conditions for the polymerization process are as follows.
The polymerization temperature is usually 130 ° C or higher, preferably 140 ° C or higher, more preferably 160 ° C or higher, more preferably 180 ° C or higher, and usually 250 ° C or lower, preferably 230 ° C or lower, more preferably 210 ° C or lower. . When the polymerization temperature is too low, the reaction rate of the polymerization reaction is slowed, and the production efficiency of the polyester unit (b) may be lowered. If the polymerization temperature is too high, the molecular weight distribution may be widened, the polyester resin may be decomposed during the polymerization, or coloring may occur.

  The pressure during the polymerization is not particularly limited, and it may be under normal pressure, under pressure, or under reduced pressure, but usually under reduced pressure.

  The polymerization time is usually 1 hour or longer, preferably 5 hours or longer, more preferably 10 hours or longer, and usually 100 hours or shorter, preferably 80 hours or shorter, more preferably 50 hours or shorter, even more preferably 40 hours or shorter. . In consideration of manufacturing efficiency and the like, it is preferable to select from the above range.

  In addition, you may add stirring etc. suitably as needed at the time of a polymerization reaction.

(V) Other:
After the polymerization step, the obtained polyester unit (b) may be used as it is, but may be subjected to a post-treatment if necessary. Examples of the post-treatment include solvent removal treatment in the case of using a solvent, isolation / purification treatment of the obtained polyester unit (b), modification treatment of the polyester unit (b), and the like. In order to improve the efficiency of the production process, it is preferable to use the obtained polyester unit (b) as it is without performing post-treatment.

-Polylactic acid unit (a) polymerization method Examples of the method for polymerizing the polylactic acid unit (a) to the polyester unit (b) include solution polymerization, melt polymerization, interfacial polycondensation, etc. And melt polymerization is preferred.

For the production of the polylactic acid unit (a), ring-opening polymerization of lactide is usually used. For example, in the case of producing a polylactic acid unit (a), a polyester unit (b) having hydroxyl groups at both ends or one end and L- (or D-) lactide are charged as raw materials, and a catalyst is charged. Is heated to carry out a ring-opening polymerization reaction. The polymerization reaction at this time can set appropriate conditions conventionally employed, and is not particularly limited.
Furthermore, when polymerizing other polylactic acid units (a) and polyester units (b), the block copolymer (I) is obtained by repeating the same polymerization step.

  Specific procedures, conditions, etc. of the polymerization step are not particularly limited, and known procedures, conditions, etc. of the polylactic acid block copolymer can be applied as they are. The polymerization time is usually 10 minutes or more, preferably 30 minutes or more, more preferably 1 hour or more, and usually 24 hours or less, preferably 10 hours or less, more preferably 5 hours or less, and even more preferably 3 hours or less. . In consideration of manufacturing efficiency and the like, it is preferable to select from the above range. In addition, about the catalyst used at the time of superposition | polymerization, the presence or absence of a solvent, the system of reaction, and other matters, it can be made to be the same as that of what was described by the manufacturing method of the said polyester unit.

  When the finally obtained block copolymer (I) is made into a stereocomplex, the stereocomplex is obtained by a process such as melt molding or distilling off the solvent from a solution once dissolved in an organic solvent. can do.

<Method for producing resin composition>
The resin composition can be produced by a method of blending the above-described two types of polyester resins (block copolymer (I)) by a known method, adding the above additives and fillers as necessary. it can. For example, (poly L-lactic acid)-(aliphatic polyester)-(poly L-lactic acid) triblock copolymer and (poly D-lactic acid)-(aliphatic polyester)-(poly D-lactic acid) triblock copolymer A blending method and the like can be performed by a known method. When the resin composition contains two types of block copolymers (I), for example, after making a uniform solution in which two types of block copolymers are dissolved in the same organic solvent , A method for producing a cast film, or after dissolving two types of block copolymers in the same organic solvent to make a uniform solution, a mixed solution in a large excess solvent in which both block copolymers do not dissolve And a method of recovering the precipitated solid and then mixing the two types of block copolymers to a temperature higher than the melting point of both copolymers and mechanically mixing them in a molten state. A method of mixing as a uniform solution is suitable for forming a stereocomplex.

D. Mechanical properties of polyester resin and resin composition The mechanical properties of the polyester resin or resin composition of the present invention should be evaluated by known methods such as a tensile test, an impact resistance test, a compressive strength test, and a tear strength test. I can do it.

  The tensile elastic modulus of the polyester resin or resin composition of the present invention is usually 1 MPa or more and 3000 MPa or less. Although a suitable range varies depending on the application, it is preferably 10 MPa or more, more preferably 100 MPa or more, still more preferably 500 MPa or more, and particularly preferably 1000 MPa or more. If the tensile modulus is smaller than the lower limit, sufficient rigidity and hardness may not be obtained.

  The tensile strength at break of the polyester resin or resin composition of the present invention is preferably 1 MPa or more, more preferably 10 MPa or more, still more preferably 20 MPa or more, and particularly preferably 30 MPa or more. If the tensile strength at break is smaller than the lower limit, sufficient strength as a practical material cannot be obtained, and there is a possibility that it cannot withstand actual use.

  The tensile elongation of the polyester resin or resin composition of the present invention is preferably 5% or more, more preferably 10% or more, still more preferably 100% or more, and particularly preferably 400% or more. If the tensile elongation is smaller than the lower limit, sufficient strength as a practical material cannot be obtained, and there is a possibility that it cannot be used in actual use.

  In addition, the tensile modulus of elasticity, tensile breaking strength, and tensile elongation of the polyester resin or the resin composition are the stress at break in the tensile test of the polyester resin and the sample film obtained by molding the resin composition, In detail, it measures by the method described in the term of the below-mentioned Example.

E. Uses Examples of uses of the polyester resin and the resin molded body of the present invention include molded bodies.
<Molded body>
The polyester resin and the resin composition of the present invention can be molded into an arbitrary form such as a film, a sheet, a fiber, a foam, an injection-molded product, an extrusion-molded product, a nonwoven fabric, a porous body, and a coding layer. When manufacturing a molded object, you may mix and use for example other aliphatic polyester resin, other general purpose resin, engineering plastic resin, etc.).

  A suitable molding form of the polyester resin and the resin composition is a film. The thickness of the film is usually 0.001 μm or more and 10 mm, and the lower limit of the thickness is preferably 0.01 μm, more preferably 0.1 μm, more preferably 1 μm, and particularly preferably 10 μm. The upper limit of the thickness is preferably 5 mm, more preferably 1 mm, more preferably 500 μm, and particularly preferably 300 μm.

<Molding method>
The polyester resin or resin composition of the present invention can be subjected to molding by various molding methods applied to general-purpose plastics and functional resin materials.

  Examples of the molding method include cast molding, compression melt molding (hot press molding), dip coating molding, compression molding (compression molding, laminate molding, stampable molding), injection molding, extrusion molding, and coextrusion molding (inflation method and T Film molding by die method, laminate molding, pipe molding, electric wire / cable molding, molding of deformed material), hollow molding (various blow molding), calendar molding, foam molding (melt foam molding, solid phase foam molding), solid molding ( Uniaxial stretch molding, biaxial stretch molding, roll rolling molding, stretch-oriented nonwoven fabric molding, thermoforming (vacuum molding, pressure forming), plastic working), powder molding (rotational molding), spinning molding (melt spinning method, electrospinning method) And various non-woven fabric molding (dry method, adhesion method, entanglement method, spun bond method, etc.).

  The polyester resin and resin composition of the present invention are particularly preferably applied to injection molding, cast molding, compression melt molding (hot press molding), and dip coating molding.

  Also, these molded products are provided with chemical functions, electrical functions, magnetic functions, mechanical functions, friction / wear / lubricating functions, optical functions, thermal functions, surface functions such as biocompatibility, etc. For this purpose, it is also possible to perform various purposeful secondary processing. Examples of secondary processing include embossing, painting, adhesion, printing, metalizing (plating, etc.), machining, surface treatment (antistatic treatment, corona discharge treatment, plasma treatment, photochromism treatment, physical vapor deposition, chemical vapor deposition, Coating, etc.).

<Uses of molded products>
Examples of specific uses of the molded product of the present invention include injection molded products (for example, containers for fresh food trays and fast foods, outdoor leisure products, etc.), extruded products (films, sheets, etc., for example fishing lines, Fishing nets, vegetation nets, water-retaining sheets, etc.), hollow molded products (bottles, etc.), and other agricultural films, coating materials, fertilizer coating materials, laminate films, plates, stretched sheets, monofilaments, non-woven fabrics, flats Yarn, staple, crimped fiber, striped tape, split yarn, composite fiber, blow bottle, foam, shopping bag, garbage bag, compost bag, cosmetic container, detergent container, bleach container, rope, binding material, hygiene Daily miscellaneous goods such as cover stock materials, pen grips, toothbrush grips, buttons, goggles gaskets Food-related materials such as food packaging films and food packaging containers, automotive interior materials, automotive exterior materials, airbag covers, door clutches, side molding end caps, door mirrors and other automotive parts, housings, housing shock absorbers, mobile phones Electronic and electrical parts such as telephone connector caps, grips, touch panels, keyboards, civil engineering sheet materials such as civil engineering sheets, cables, hoses, packings, cold insulation boxes, cushion material films, multifilaments, synthetic paper, non-woven fabrics, surgical threads for medical use, Suture, anti-adhesion membrane, stent, stent coating material, artificial blood vessel, artificial bone, artificial cartilage, bone pin, bone repair material, artificial hip joint, artificial knee joint, spinal cord injury repair material, artificial ligament, artificial skin, microcapsule, etc. DDS (Drug Delivery System), wound dressings, dental materials, contact lenses, cells Nutrient container, a cell culture delivery device, and scaffolds such cells.

  In addition, information electronic materials such as toner binders and ink binders for thermal transfer, automobile interior parts such as electrical product casings, instrument panels, sheets and pillars, and automobile parts such as bumper, front grille, wheel covers and other automotive exterior structural materials. Can be used.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples as long as the gist thereof is not exceeded.
Various physical property measurements and polymer synthesis were performed as follows.

<Structure determination>
The structural analysis of the polymer was measured using a Bruker ARX spectrometer ¹ H-NMR analyzer with a deuterated chloroform solution containing a chemical shift internal standard substance tetramethylsilane.

<Molecular weight>
The number average molecular weight Mn was calculated by the terminal group determination method using the ¹ H-NMR analyzer. Further, the number average molecular weight Mn and the weight average molecular weight Mw were measured by an SEC analyzer (Analysis system manufactured by Shimadzu Corporation equipped with an LC-10ADv pump, a RID-10A RI detector, and a C-R7A chromatographic data analyzer). For triblock polymers (Examples 1 and 2, Comparative Examples 1 and 2) having a polyester unit (b) of succinic acid and 3-methyl-1,5-pentanediol (hereinafter also referred to as “Soft1”), Measured with a SEC analyzer (LC-10ADv pump, RID-10A RI detector, Shimadzu Corporation analysis system equipped with a C-R7A chromatographic data analyzer). Specifically, the number average molecular weight (Mn) and weight are determined by a calibration curve using polystyrene as a molecular weight standard substance using two TSKgel GMH _HR- M columns manufactured by Tosoh Corporation at 45 ° C. with 1,3-dioxolane as an eluent. Average molecular weight (Mw) was measured.

  About the pentablock polymer (Examples 6-8) which has Soft1 by the SEC analyzer (Shimadzu Corporation analysis system provided with LC-10ADv pump, RID-10A RI detector, C-R7A chromatographic data analyzer) It was measured. Specifically, the number average molecular weight (Mn) and the weight average by a calibration curve using PMMA as a molecular weight standard substance using a Shodex HFIP-806M column manufactured by Showa Denko KK at 40 ° C. with HFIP (hexafluoroisopropanol) as an eluent. Molecular weight (Mw) was measured.

  Polymers (Examples 3-5, 9, and 10) having polyester units (b) (hereinafter also referred to as “Soft2”) of succinic acid and 1,4-butanediol, and PDLA (poly D-lactic acid) ( For Comparative Example 3) and PLLA (poly L-lactic acid) (Comparative Example 4), LC-20AD pump, RID-10A RI detector, 2 TSKgelSuperHZM-N columns manufactured by Tosoh Corporation at 40 ° C. with chloroform as an eluent. The number average molecular weight (Mn) and the weight average molecular weight (Mw) were measured by a calibration curve using polystyrene as a molecular weight standard substance.

<Thermal properties>
In the copolymer having Soft1, the melting point and glass transition temperature were measured with a Perkin Elmer Diamond DSC thermal analyzer under α-alumina as a reference under nitrogen. After the sample was heated from −50 ° C. to 240 ° C. at a heating rate of 20 ° C./min (first temperature increase), it was rapidly cooled by quenching from 240 ° C. to −50 ° C. using an intercooler for 1-2 minutes. . Next, the temperature was raised from −50 ° C. to 240 ° C. at a rate of 20 ° C./min (second temperature rise). Finally, the temperature was lowered (cooling process) from 240 ° C. to 20 ° C. at 10 ° C./min. At this time, the heat of fusion was measured by the melting point due to the endothermic peak at the second temperature increase, the glass transition temperature due to the inflection point, and the area of the endothermic peak.
In the copolymer having Soft2, the melting point and glass transition temperature were measured under nitrogen using α-alumina as a reference by a SEIKO INSTRUMENT SSC / 5200 DSC thermal analyzer. The sample was heated from 25 ° C. to 240 ° C. at a rate of temperature increase of 10 ° C./min (first temperature increase), and then rapidly cooled by standing in liquid nitrogen at 240 ° C. to −60 ° C. Next, the temperature was raised from −50 ° C. to 240 ° C. at 10 ° C./min (second temperature rise). Finally, the temperature was lowered (cooling process) from 240 ° C. to 20 ° C. at 10 ° C./min. At this time, the heat of fusion was measured by the melting point due to the endothermic peak at the second temperature increase, the glass transition temperature due to the inflection point, and the area of the endothermic peak.

<Tensile test>
The mechanical properties of the polyester resins or resin composition films obtained in Examples and Comparative Examples were measured by a tensile test. The tensile tester was measured by a STA-1150 apparatus manufactured by Orientec Co., Ltd. at room temperature under a distance between marked lines of 20 mm and a crosshead speed of 50 mm / min. A film having a thickness of 100 μm was subjected to a tensile test, and the measured values of tensile strength, tensile elastic modulus, and tensile elongation were obtained by averaging the number of repeated samples n = 5 or more.

<Crystal analysis>
Wide angle X-ray diffraction (WAXS) is a Rigaku 2000FSL X-ray diffraction system (Rigaku RINT2000 X-ray generator 40 kV-50 mA nickel filter Cu-Kα irradiation, λ = 0.154 nm, 2θ = 5-40 ° C., scan rate 2 ° / min) Used.

<Soft Segment = Synthesis of Polyester Unit (b)>
A flask was charged with 59.1 g (0.501 mol) of succinic acid (SA) and 70.9 g (0.601 mol) of 3-methyl-1,5-pentanediol (MPD), and the flask was heated to 150 ° C. The internal pressure of the flask was reduced to 30 Torr and reacted for 3 hours. As a result, SA / MPD oligomer (degree of polymerization 1 to 3) was obtained in a yield of 85%. The obtained SA / MPD oligomer (50 g) was subjected to a polymerization reaction for 36 hours at 190 ° C. and an internal pressure of 5 Torr with SnCl ₂ .2H ₂ O (0.15 g) and p-toluenesulfonic acid (0.15 g), and the number average molecular weight Mn = 20,000 polyester SA / MPD was obtained. The number average molecular weight and structure of the polymer were confirmed by ¹ H-NMR. The attribution is shown below.

δ (ppm) = 0.95 (OCH ₂ CH ₂ CH (C H ₃ ) CH ₂ CH ₂ O),
1.49 (OCH ₂ C H ₂ CH (CH ₃ ) C H ₂ CH ₂ O),
1.68 (OCH ₂ CH ₂ C H (CH ₃ ) CH ₂ CH ₂ O),
2.61 (COOC H ₂ C H ₂ COO),
3.68 (OCH ₂ CH ₂ CH (CH ₃ ) CH ₂ C H ₂ OH),
4.13 (OC H ₂ CH ₂ CH (CH ₃ ) CH ₂ C H ₂ O)

<Synthesis of triblock copolymer>
Polyester SA / MPD having a number average molecular weight of 20,000 was charged into a reaction vessel, and then L-lactide and tin octylate (1.78 × 10 ⁻⁵ mol% with respect to L-lactide) were charged under nitrogen. The charging weight ratio of the polyester SA / MPD and L-lactide was determined so as to be equal to the copolymerization ratio of the polylactic acid unit (lactide) and the polyester unit (SA / MPD) of the triblock copolymer to be synthesized. The polymerization reaction was performed in the reaction vessel at 180 ° C. for 1 hour. The obtained (poly L-lactic acid)-(polyester SA / MPD)-(poly L-lactic acid) triblock copolymer was dissolved in dichloromethane, precipitated in a large excess of methanol, filtered and dried. The number average molecular weight and structure of the polymer were confirmed by ¹ H-NMR.

<Synthesis of pentablock copolymer>
Triblock copolymer (poly L-lactic acid)-(polyester SA / MPD)-(poly L-lactic acid) obtained by the above method, D-lactide and tin octylate (1.78 × for D-lactide) 10 ⁻⁵ mol%) was charged into the reaction vessel. The charging weight ratio of the triblock copolymer and D-lactide was determined according to the copolymer composition ratio of the pentablock copolymer to be synthesized. The reaction vessel was heated at 190 ° C. for 1 hour to carry out the polymerization reaction. The polymer obtained was dissolved in dichloromethane / 1,1,1,3,3,3-pentafluoro-2-propanol (90/10 vol%), precipitated in a large excess of methanol, filtered and dried. A pentablock copolymer of (poly D-lactic acid)-(poly L-lactic acid)-(polyester SA / MPD)-(poly L-lactic acid)-(poly D-lactic acid) was obtained. The number average molecular weight and structure of the polymer were confirmed by ¹ H-NMR.

<Film production method>
The obtained copolymer was dissolved in dichloromethane or dichloromethane / 1,1,1,3,3,3-pentafluoro-2-propanol (90/10 vol%) at 5 g / dL and cast on a glass substrate. A film was prepared.

[Example 1]
In the method of <Synthesis of Triblock Copolymer>, poly L-lactic acid (12.5 k) -Soft1 (polyester SA / polyester) was prepared by setting the weight ratio of L-lactide and soft segment (SA / MPD) to 25:20. MPD) (20k) -poly L-lactic acid (12.5k) triblock copolymer was obtained. (The numbers in the parentheses are the theoretical molecular weights calculated from the charging ratio. For example, 20k indicates that the theoretical molecular weight is 20,000.)
Further, poly-D-lactic acid (12.5 k) -Soft1 (polyester SA / MPD) (20 k) was obtained in the same manner except that L-lactide was changed to D-lactide and L-lactide was changed to D-lactide. ) -Poly D-lactic acid (12.5k) triblock copolymer was obtained. Equal amounts of these two types of triblock copolymers were blended in solution to prepare a cast film comprising the resin composition of the present invention by the method described in <Film Preparation Method>. Using this cast film, a tensile test and thermal analysis were performed. The blended cast film exhibited a melting point derived from the stereo complex at 203 ° C. The tensile test showed a tensile elongation of 200% or more. The results are shown in Table 1. Further, Table 2 shows the number average molecular weight Mn and the weight average molecular weight Mw measured by SEC.

[Example 2]
The copolymer composition ratio of the triblock copolymer was changed as shown in Table 1, blended, and a tensile test and thermal analysis were conducted in the same manner as in Example 1. The blended cast film exhibited a melting point derived from the stereo complex at around 200 ° C. The tensile elongation was 20% or more, and a flexible film having excellent mechanical properties was obtained. Table 1 shows each physical property, and Table 2 shows the number average molecular weight Mn and the weight average molecular weight Mw measured by SEC.

[Example 3]
<Soft segment = Polyester unit (b) except that MPD was changed to 1,4-butanediol (BD) and p-toluenesulfonic acid was not used in <Synthesis of soft segment = polyester unit (b)> Soft2 (polyester SA / BD) was obtained in the same manner as in the above synthesis. Structure confirmation and number average molecular weight Mn measurement were performed by ¹ H-NMR. By performing the polymerization reaction for 15 hours, a polyester having Mn = 22,000 was obtained. (Poly L-lactic acid)-(Poly D-lactic acid) -Soft 2 (Polyester SA /) by using the polyester unit (b) of Soft 2 and the same method as described in <Synthesis of Pentablock Copolymer>. A pentablock copolymer (polyester resin of the present invention) of (BD)-(poly D-lactic acid)-(poly L-lactic acid) was obtained. About this pentablock copolymer, molecular weight and structure were confirmed by < ¹ > H-NMR. According to SEC measurement, Mn was 73,000 and Mw was 101,000. The results of thermal analysis are shown in Table 1. The melting point derived from the stereo complex was shown at 209 ° C. In addition, Table 2 shows the number average molecular weight Mn and the weight average molecular weight Mw measured by SEC.

[Examples 4 and 5]
Using Soft2 (polyester unit (b)) used in Example 3, the charged composition ratio is shown in Example 4 or 5 in Table 1 by the same method as described in <Synthesis of Pentablock Copolymer>. A pentablock copolymer was synthesized in the same manner as in Example 3 except that the composition was changed to (poly L-lactic acid)-(poly D-lactic acid) -Soft 2 (polyester SA / BD)-(poly D-lactic acid). A pentablock copolymer (polyester resin of the present invention) of-(poly L-lactic acid) was obtained. The Mn by SEC measurement was 93,000 in Example 4 and 110,000 in Example 5. Mw was 168,000 in Example 4 and 200,000 in Example 5. The results of thermal analysis are shown in Table 1. In addition, Table 2 shows the number average molecular weight Mn and the weight average molecular weight Mw measured by SEC. The melting point derived from the stereo complex was shown around 200 ° C., and it was found that the heat resistance was good.

[Examples 6 to 8]
Using the method described in <Synthesis of pentablock copolymer> using polyester SA / MPD having Mn = 20,000 synthesized by the method of <soft segment = synthesis of polyester unit (b)> A pentablock copolymer (polyester resin of the present invention) was synthesized so as to have a copolymer composition ratio of 1 in Examples 6 to 8. Mn measured by SEC was 54,000 in Example 6, 71,000 in Example 7, 90,000 in Example 8, and Mw was 150,000 in Example 6, 215,000 in Example 7. Example 8 was 322,000. The results of thermal analysis and tensile test are shown in Table 1. The cast film exhibited a melting point derived from the stereo complex at around 190 ° C. In the tensile test, the balance between elastic modulus, strength and tensile elongation was good. Table 1 shows each physical property, and Table 2 shows the number average molecular weight Mn and the weight average molecular weight Mw measured by SEC. FIG. 1 shows X-ray diffraction patterns of the resin compositions of Examples 6 to 8. A peak derived from the stereocomplex was observed at 2θ = 12 °.

[Examples 9 and 10]
Soft 2 (polyester SA / BD) with Mn = 22,000 was obtained in the same manner as in Example 3 except that the polymerization time was changed to 35 hours in the same manner as in Example 3. In the same manner as in Example 3, pentablock copolymers (polyester resins of the present invention) having the composition ratios of Examples 9 and 10 in Table 1 were obtained. Structure confirmation and number average molecular weight Mn measurement were performed by ¹ H-NMR. The Mn by SEC measurement was 68,000 in Example 9 and 107,000 in Example 10, and Mw was 147,000 in Example 9 and 133,000 in Example 10. The results of thermal analysis are shown in Table 1. In addition, Table 2 shows the number average molecular weight Mn and the weight average molecular weight Mw measured by SEC. A melting point of 200 ° C. or higher derived from a stereo complex was exhibited.

[Comparative Examples 1 and 2]
In the same manner as in Example 1, the charge composition ratio was adjusted so as to be the copolymer composition ratio of Comparative Examples 1 and 2 in Table 1 to obtain a triblock copolymer. Table 1 shows the results of thermal analysis and tensile test of these triblock copolymers alone. The number average molecular weight Mn and the weight average molecular weight Mw are shown in Table 2. The melting points were all below 170 ° C.

[Comparative Example 3]
The thermal analysis and tensile test results of poly D-lactic acid alone are shown in Table 1. The melting point was 170 ° C. or less, and the film prepared by casting was a fragile film having a small tensile elongation. The results are shown in Table 1. The number average molecular weight Mn and the weight average molecular weight Mw measured by SEC are shown in Table 2.

[Comparative Example 4]
Using L-lactic acid homopolymer (number average molecular weight 123,000) and D-lactic acid homopolymer (number average molecular weight 118,000), a film was prepared by the same method as in Example 1 and the physical properties were measured. The results are shown in Table 1. In addition, Table 2 shows the number average molecular weight Mn and the weight average molecular weight Mw measured by SEC. The film was brittle and had a small elongation in the tensile test.

  As shown in Table 1, according to the present invention, it is possible to provide a polyester and a polyester composition having high heat resistance and excellent mechanical properties. Specifically, when the resin composition (stereocomplex) of the present invention of Example 1 is compared with the polyester resin that is not a stereocomplex of Comparative Example 2 in which a polylactic acid is a polyester resin having only L form, tensile elongation is compared. It is clear that the resin composition of Example 1 is superior in mechanical properties such as.

  The polyester resin and resin composition of the present invention have a high melting point and are excellent in flexibility and mechanical properties. Therefore, these are highly industrially applicable materials applicable to various fields as environment-friendly materials, for example, fibers and medical materials.

Claims (13)

A polyester resin, which is a block copolymer (I) mainly composed of a polylactic acid unit (a) and a polyester unit (b), and is a stereocomplex. The polyester resin according to claim 1, wherein the melting point derived from the stereocomplex of the polyester resin is 180 ° C or higher. The polyester resin according to claim 1 or 2, wherein the block copolymer (I) is a triblock copolymer. The polyester resin according to claim 1 or 2, wherein the block copolymer (I) is a pentablock copolymer. The polyester resin according to claim 1, wherein the polyester unit (b) is an aliphatic polyester unit. The polyester resin according to any one of claims 1 to 5, wherein the polyester unit (b) is composed of an aliphatic dicarboxylic acid and an aliphatic diol. A resin composition comprising two or more polyester resins which are block copolymers (I) mainly composed of a polylactic acid unit (a) and a polyester unit (b), and is a stereocomplex. The resin composition according to claim 7, wherein the melting point derived from the stereocomplex of the resin composition is 180 ° C or higher. The resin composition according to claim 7 or 8, wherein the block copolymer (I) is a triblock copolymer. The resin composition according to claim 7 or 8, wherein the block copolymer (I) is a pentablock copolymer. The resin composition according to any one of claims 7 to 10, wherein the polyester unit (b) is an aliphatic polyester unit. The resin composition according to any one of claims 7 to 11, wherein the polyester unit (b) comprises an aliphatic dicarboxylic acid and an aliphatic diol. A molded article comprising the polyester resin according to any one of claims 1 to 6 or the resin composition according to any one of claims 7 to 12.

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