DESCRIPTION
POLYLACTlDE COMPOSITION
Field of the Invention
The present: invention relates to a composition comprising polylactide. More specifically, it relates to a composition which has excellent heat stability, mechanical strength and color and can be kept for a long time.
Description of the Prior Arc
Since most plastics are light and stiff, have high durability and can be easily molded into any shape, they are mass-produced to support our lives in various ways . However, whan they are thrown away into the environment, they are not easily decomposed and are accumulated. When they are burnt, they produce a large amount of carbon dioxide which accelerates global warming.
In view of the above situation, studies on biodegradable plastics which are degraded by microorganisms are now under way energetically- Biodegradable plasties have an aliphatic carboxylic acid ester unit and are easily degraded by microorganisms. On the other hand, they have low heat stability, and their molecular weights tend to become lower and their colors tend to become worse in the step of exposing them to a high temperature, such as melt spinning, injection molding or melt film formation.
Out of the biodegradable plastics, polylactide is a plastic which has excellent heat resistance and good balance between color and mechanical strength, when it is compared with petroleum-based resins typified by polyethylene terephthalate and polyamide, there is a world of difference in heat stability between them. To resolve this situation, various studies on the improvement of the heat stability of

polylactide have been made.
Per example, patent document 1 proposes that a phosphoric acid-based compound or phosphorous acid-based compound should be added as a catalyst deactivator to polylactide when its molecular weight reaches 50,000. However, the addition of the catalyst deactivator to polylactide having a low molecular weight as in patent document 1 means that the subsequent polymerization reaction is impeded, thereby making it impossible to obtain a polymer having a high molecular weight.
Patent documents 2 and 3 propose that an acidic phosphoric acid ester or & chelating agent should be added as a catalyst deactivator to improve the he&t stability of polylactide. Since the safety against toxicity of the acidic phosphoric acid ester disclosed by patent documents 2 and 3 is not ensured, when the resin is scrapped, it pollutes, the environment and its use in food is limited, The chelating agent generally has low heat resistance and is .baked before it captures a metal catalyst to become a serious coloring factor.
Meanwhile, it is known that the heat stability of polylactide is affected not only by a polymerisation catalyst bun also by the spontaneous disconnection of the main chain (refer to non-patent documents l and 2]. The spontaneous disconnection of the main chain proceeds monolithically to produce a carbon radical, acyl radical, oxo radical or carboxyl radical, thereby causing the production of a lactide by depolymerisation and an increase in the amount of a coloring component such as & pyruvic acid derivative due to a rebonding or dehydrogenation reaction, or disproportionation.
To improve the heat stability, coioz and hydrolytic resistance of polylactide while retain.1nc Its safety, further improvement must be made on the suppression of

depolymerization caused by the residual catalyst and the suppression of a reduction in the molecular weight caused by the disconnection of the main chain, (patent document i) Japanese Patent No. 2,862,071 (patent document 2} Japanese Patent No. 3,4 67,588 (patent document 3) JP-A No, 10-3665l'
(non-patent document 1) Polymer Degradation and Stability,. 1985, vol. 11, pp. 309-326, I, C. McNeil et al. (non-patent document 2) Journal of .Analytical and Applied Pyrolysis, 1997, vol. 40-41, pp. 43-53, F. D. Copinche et al.
Summary of the Invention
It is therefore an object of the present invention to provide a composition which comprises polylactide and has excellent heat stability. It is another object of the present invention to provide a composition which comprises polylactide and has excellent color. It is still another object of the present invention to provide a composition which comprises polylactide and has excellent hydrolytic
resistance.
The inventors of the present invention have conducted intensive studies on a deactivator which is effective for deactivating the residual catalyst contained in polylactide, As a result, they have found that when a hypophosphorous acid-based deactivator is contained an polylactide, the residual catalyst contained in polylastide can be deactivated efficiently and a composition having excellent heat stability and color is obtained. The present invention has been accomplished based on thit rinding.
The inventors of the present invention have also found that when a met&phosphoric acid-betsec deactivator is contained in polylactide, the residual catalyst and water contained in polylactide can be deactivated effectively a.nd

a composition having excellent heat stablity and hydrolytic resistance can be obtained. The presjeat invention has been accomplished based on this finding.


in terms of standard polystyrene measured by gel permeation chromatography 1GPC) using chloroform as an eluent.
PolylaLicide is preferably poly-L-lactide, poly-D-lactide or a mixture of both. The weight ratio of poly-L-laer. Lde to poly-D-lactide ia preferably 90:10 to 10: dO, more preferably ?5: 25 to 25f75, much more preferably 60:40 to 4C;6C.
Poly-L-lactide contains an L-lactide unit as the major component. roly-L-Iactide contains an L-lactide unit in an amount of preferably 9C to 100 molt, more preferably 95 to 100 mol%, much more preferably 98 to 2 00 mol%. The other units are a o-lactide unit and a unit other than lactide. The total amount of tne D-lactide unit and the unit other than lactide is , to 10 mol%, preferably 0 to 5 molt, more preferably o to a mol%.
Poly-D-lactide contains a D-lactide unit as the major component, Poly-D-lactide contains a D~lactide unit in an amount of preferably 90 to IOC molV, more preferably 95 to DC mo1%, much more preferably 98 to 100 mo1%. The other mits are an L-lactide unit and a unit other than lactide. The total amount of the L-lactide unit and the unit other than lactide is 0 to 10 molt, preferably 0 to 5 mol%, more preferably o to :.: mol%..
The unit other than lactide is a unit derived from a dicarboxylic acid, polyhydric alcohol, hydroxycarboxylie acid or lactone having a functional group capable of forming two cr more ester bonds, or a unit derived from a polyester*, polyetner or polycarbonate which comprises the above constituent components.
Examples -jf che dicarboxylic acid include succinic acid, adipic acid azelaic acid, sebacic acid, terephthalic acid and isophthalic acid. Examples of the polyhydric alcohol include aliphatic polyhydric alcohols such aG ethylene glycol, propylene glycol, butanediol, pentsnediol,

hexanediol, octanediol, glycerin, sorbitan, neopentyl glycol, diethylene glycol, triethylene glycol, polyethylene glycol and polypropylene glycol, and aromatic polyhydric alcohols such at- adduct of bisphenol with ethylene oxide. Examples of the hydroxycarbcxylic acid include glycolic acid and hydroxybunyric acid. Examples of the lactone include,
glycolide, c-caprolactone glycolidfc, e-caprolactone, P-propiclaetone, 6-butyroiactone, ß- or y-butyrolactone, pivalolactone and 6-valerolactcne.
Poly-L-lutide and poly-r-lactide can be manufactured by known method . For example, they can be manufactured by heating L- or D-lactide in the presence of a metal catalyst to ring-opening polymerize it. Alternatively, they can be manufactured by crystallising low molecular weight polylactide containing a metal catalyst and heating it under reduced pressure or in a inert gas stream to solid phase polymerize it. Further, they can be manufactured by a direct polymerisation method in which lactide is dehydrated and condensed in the presence or absence cf an organic solvent.
The polymerisation reaction can be carried out in a conventionally toown reactor. For example, vertical reactors having high-viscosity agitating elements such as helical ribbon elements can be used alone or in combination,
An alcohol may be used as a polymerization initiator. Preferably, the alcohol does not impede the polymerization of pclylactide and is non-volatila. Preferred examples of the alcohol include decanol, dodecanol, tetradecanol, hexadecanol and octadecanol.
In the solid-phase polymerisation method, a lactide polyester having a relatively low molecular weight obtained by the above ring-opening polymerisation or the direct polymerisation of lactide is used as a prepolymer., It is preferred from the viewpoint of preventing fusion that the prepolymer should be crystallised at a temperature range of

its glass transition temperature (Tg) or higher and lower than its melting point (Tm) in advance. The crystallized prepolymer is filled into a fixed vertical reactor cr a reactor whoee vessel turns, such as a tumbler or kiln and heated at a temperature of the glass transition temperature (Tg) of the prepolymer or higher and lower than the melting point (Tm). If the polymerisation temperature is raised stepwise along with the proceeding' of polymerization, there will be no problem. It is also preferred that the inside pressure of the above reactor should be reduced to remove water generated during solid-phase polymerization efficiently or that a heated inert gas stream should be circulated.
(stereocomplex polylactide)
Polylactide is preferably so-called "stereocomplex polylactide" which is a mixture of poly-L-lactide and poly-D-lactide and contains stereocomplex crystal. The stereocomplex crystal is formed by mixing together poly-L-lactide and poly-D-lactide. In this case, the weight ratio of poly-L-lactide to poly-D-lactide is preferably 90:10 to 10:90, more preferably 75:25 to 25:75, much more preferably 60:40 to 40; 60. The weight average molecular weights (Mw) of poly-L-lactide and poly-D-lactide are each preferably 100,000 to 500,000, more preferably 150,000 to 350,000.
The stereocomplex crystal content (X) of the composition of the present invention is preferably SO to 100 %, more preferably 95 to 100 %. The stereocomplex crystal content (X) is represented by the following equation,
X = {AHB/(AHA.+ AHB)) x 100 (%)
In the above equation, AHB is the fusion enthalpy of a crystal melting point which appears at 150CC or higher and
lower than 190°C, and AHB is the fusion enthalpy of a crystal

melting point which appears at 190°C or higher and lower than
250°C.
The stereocomplex polylactide as used in the present invention has fusion peaks at 195°C or higher which account for preferably 80 % or more, more preferably 90% or more, much more preferably 95 V or more of the total of all the fusion peaks during temperature elevation when measured by a differential scanning calorimeter (DSC). The melting point of the stereocomplex polylactide is in the range of preferably 195 to 25GCC, more preferably 200 to 220°C. The fusion enthalpy is 20 J/g or more, preferably 30 J/g or more. More specifically, it is preferred that fusion peaks at 19S°C or higher should account for 30% or more of the total of all the fusion peaks during temperature elevation when measured by a differential scanning calorimeter (DSC), the melting point should be in the range of 195 to 250°c, and the fusion enthalpy should be 20 J/g or more.
The stereocomplex crystal can be manufactured by mixing together poly-L-lactide and poly-D-lactide in a predetermined weight ratio.
The above mixing can be carried out in the presence of a solvent. The mixing may be carried out in the absence of a solvent. That is, poly-L-lactide and poly-D-lactide are mixed together in a predetermined ratio and melt kneaded together, or one o£ them is molten and the other is added to and kneaded with the molten product.
(metal catalyst)
The metal catalyst used for the manufacture of poly-L-lactide or poly-D-lactide is preferably a compound of at least one metal selected from the group consisting of an alkali earth metal, a rare earth element, a transition metal of the third period, aluminum, germanium, tin and antimony. Examples of the alkali earth metal include

magnesium, calcium and strontium. Examples of the rare earth element include scandium, yttrium, lanthanum and cerium, Examples of the transition metal of the third period include titanium, iron, cobalt, nickel and zinc.
The metal catalyst is preferably a carboxylase, alkoxide, halide, oxide, carbonate, enolate salt or trifluoromethane sulfonate cf the above metal. When polymerisation activity and the color of the obtained composition are taken into consideration, tinoctylate, zinc nitrate, titanium tetraisopropoxide and aluminum triisopropoxide are particularly preferred.
The composition of the present invention comprises polylactide which is polymerized in the presence of the above metal catalyst. Therefore the composition of the present invention contains the metal catalyst in an amount of 0.001 to 1 part by weight, preferably 0.005 to 0.1 part by weight based on 100 parte by weight of polylactide. When the amount of the metal catalyst is too small, the polymerisation rate becomes too low disadvantageously. When the amount is too large, coloring caused by reaction heat, depolymeri2ation or an ester interchange reaction is, accelerated, thereby deteriorating the color and heat stability of the obtained composition.
(hypophosphorous acid-based deactivator)
The hypophosphorous acid-based deactivator is a compound having the ability of forming a sale or complex with the metal catalyst. Two hydrogen atoms showing strong reduction power are bonded to the phosphorus atom of the hydrophoephoroue acid-based deactivator, thereby making it possible to suppress an increase in tha amount of a radical or oxide produced at a high temperature. The hypophosphorous acid-based deactivator is preferably at loast one selected from the group consisting of hypophosphorous acid, an alkali

metal salt of hypophosphorous acid, an alkali earth metal salt of hypophosphorous acid and an onium salt of hypophosphorous acid.
Examples o£ the alkali metal salt of hypophosphorous acid include aodium salts and potassium salts of hypophosphorous acid. Examples of the alkali earth metal salt of hypophosphorous acid include calcium salts and magnesium salts of hypophosphorous acid. Examples of the onium salt of hypophosphorous acid include tetraethylammonium hypophosphite, cetra-n-butylammonium hypophosphite, tetraethylphosphonium hypcphosphite and tetra-rt-bucylphoephonium hypophosphite. The hypophosphorous acid-based deactivator is preferably hypophosphorous acid, sodium hypcphosphite, potassium hypophoephite, magnesium hypophosphite, calcium hypophoephite and ammonium hypophosphite. Hypophosphorous acid is particularly preferred from the viewpoints of the deactivation power of the metal catalyse and the suppression of an oxide.
The content of the hypophosphorous acid-based deactivator is 0.001 to 5 parts by weight, preferably 0.01 to 0,5 part by weight based on 100 parts by weight of polylactide. When the content of the hypophosphorous acid-based deactivator is too low, its reaction efficiency with the residual polymerization catalyst becomes too low, thereby causing the nonuniform deactivation of the polymerisation catalyst- When the content is too high, the plasticisation of the composition cyufced by the hypophosphorous acid-based deactivator or a reduction in hydrolytic resistance caused by an increase in water absorptivity becomes marked.
The hypophosphorous aciv based deactivator can be directly added to and kneaded in a rector in the latter stage of polymerization in the ring-openiny polymerisation method.

it may be kneaded by means of an extruder or kneader after it is molded into A chip, when the uniform distribution of the hypophospborcus acid-based deactivator in polylactide is taken into consideration, the use of an extruder or kneader ia preferred. It is also preferred that the discharge unit c..f the reactor should be directly connected to the extruder to add the hypophoephorous acid-based deactivator from a side feeder. To add the hypophoaphcroua acid-based deactivator by the above methol, it is preferred that an aqueous solution of the deactivator or a solution of the deactivator dissolved in a polar organic solvent such as an alcohol or tetrahydrofuran should be added.
in the solid-phase polymerisation method, it is possible to knead solid polylactide obtained at the end of polymerization with the hypophoaphoroue acid-baaed deactivator by means of an extruder or kneader or to knead solid polylactide with a mater batch containing the hypophosphorous acid-based deactivator by means of an extruder or Kneader.
Since a high temperature of 180CC or higher is required to produce stereocompiex poly-L-lactide and poly-D-lactide, the hypophosphorous acid-based deactivator is prsferably added by any one of the above methods before the production of the- stereocomplex poly-L-lactide and poly-D-iaetide.
(metaphcsphoric acid-based deactivator)
The metaphosphoric acid-based deactivator used in the present invention is a compound obtained by condensing 3 to 200 phosphoric acid units in a loop and hae the ability of forming a complex with a metal catalyst or water. The mecaphosphoric acid-based deactivator is a cyclic multidentate ligand, has a larger complex stability constant thsn phosphoric acid, phosphorous acid, pyrophospheric acid, polyphosphoric acid and esters thereof which are monodendate

or chain multidendate ligands, and can capture a metal catalyst and water efficiently and firmly. The metaphosphoric acid-based deactivator is preferably at least one selected from the group consisting of metaphosphoric acid, an alkali metal salt of metaphosphoric acid, an alkali earth metal salt of metaphosphoric acid and an onium salt of metaphosphoric acid. Examples of the alkali metal salt of metaphosphcric acid include sodium salts and potassium salts of metaphosphoric acid. Examples of the alkali earth metal salt of metaploephcric acid include calcium salts and magnesium salts of metaphosphoric acid. Examples of the onium salt of metaphosphcric acid include tetraethylammonium metaphosphate, tetra-n-eutylamnonium metaphoephate, tetraethylphosphonium metaphosphate and cenra-n-butylphoflphonium metaphosphate.
The menaphosphoric acid-based deactivator is preferably a least one selected from the group consisting of a compound represented by the following formula, and an alkali metal salt, an alkali earth metal salt and an ouium sale thereof-



Metaphosphoric acid-based deactivators have a glass transition temperature of 130 to 150°C, whihc slightly differs according to preparation prccees. Since a metaphospiaoric acid-based deactivator having a glass transition temperature of 10D*C or higher alone easily dried by heating in a solid state, it can be direcly added to and kneaded in a reactor in the latter stage of polymerization in the ring-opening polymerisation method advantageoualy.


The composition of the present invention has a weight average molecular weight [Mw] of lOO/OGO to 500,000, preferably 150. 000 to 350, 000, is excellent m heat stability,

I
I
color arid hydrolytic resistance and can be advantageously used for melt spinning, melt film formation and injection molding.



hexafluoroisopropanol. They may be used alone or in combinsition of two or mors. Th^ miring may be carried out in the absence of a solvent. That is, poly-L-lactide and poly-D-lactide are mixed together in a predetermined ratio and melt kneaded together, cr one of them is molran and the other is added to and kneaded with the molten product.
In the above process, tha following poly-L-lactide and poly-D-lactide are mixed together. The alphabets below

indicate the following.
(L) pcly-L-lactide contAining substantially no metal
catalyst
(Lc) poly-L-lactide containing a metal catalyst
(Lcp) poly-L-lacrids containing a metal catalyst and a
hypophosphorous acid-based deactivator or mfetaphogphoric
acid-based deactivator
(D) pcly-D-lactide containing substantially no metal
catalyst
(DC) poly-D-l&ctide containing a metal catalyst
(Dcp) poly-D-lactide containing a metal catalyst and a
hypophoephorouG acid-based deactivator or me taphosphoric
acid'hasftd deactivator



resistance of the composition. An incrcase in the amountt of the terminal carboxyl group is an index of the degree of hydrolysis. The amount of the terminal carboxyl group was


(5) evaluation of color of composition
The evaluation of the color of the composition WAS made based on L, a and b values obtainftd by the uv2400PC ultraviolet-visible spectrometer of Shimadsu Corporation. The evaluated sample was a 40 nm-thick film which was farmed from a 15 wt% dichloromethane edlucion of the composition as a stock solution by a solvent casting method.


After the end of polymerization; 0.02 part by weight of hypophosphorous acid (man.uf actured by wako Pure Chemica1 Industries, Ltd.) was added from the material feed port and kneaded for 15 minutes. Finally, surplus L-iactide was volatilized and a strand- like poly-L-lactide composition was discharged from the discharge port of the reactor and pelletised while it wae cooled. The Mw and lactide content of the obtained comosition are shown in Table 1,
The obtained composition was ground with a grinder, and 10 g of the grains was fed to a test tube with a cock made of the Pyrx (registered trademark of Corning CO» , Ltd,) heat resistant glass. Thereafter, the inside of the Pyrex (registered trademark) test tube was substituted by nitrogen to oarry out a heat stability test at: 260°C for ID minutes. After the end o£ the test, the composition was taken out to measure its Mw and lactide content. The measurement results

are shown in Table i. The I,, a and b values of the composition at this point are shown in Table 2. .
Comparative Example 1
A composition wa$ obtained in the same manner as in Example 1 except that hypophosphorous acid was not added. when a heat stability test was made on this composition, the composition after the heat stability i:est was fragile, and lactide crystal which was a decomposed product adhered to the Pyrex (registered trademark! test tube used in the test. The Mw and lactide content of the composition after the heat stability test are shown in Table 1. The L, a and b values of the composition at thie point areshown in Table 2,



(manufacture of poly-D-laicridfe)
Poly-D-lactide was prepared by the same operation as above. That is, 100 parts by weight o£ relactid£ and 0.15 part by weight of stearyl alcohol were ted, the inside of the reactor was substituted by nitrogan 5 times, and D-lactide was molten at 190*C. WhenD-lact..de was completely molten, 0.05 part by weight of tin 3-ethylhexanoate was added
from the matterial feed port together wiln 500 µ1 of toluene to carry out polymerization at 190°C for 1 hour- After the

end of polymerization 0 . 02 part, by weight of hypophophorous acid (manufaccured by Wako Pure Chemical industries, Ltd., phosphinic acid) was added from the material feed port and kneaded for 15 minutes. Finally, solplus D-lactide was volaciliaed ana etrand-like pcly-D- actide was discharged from the discharge port of the reactor and pelletired while


and b values of the composicion are snown in Table 4.
Comparative Example 2
A composition was obtained in the same manner as in Example 2 except that the hypophosphorouB acid-based deactivator was not added. When a heat etability test was made on this cpmposition, the composition afrer the heat stability test was fragile and assumed broen, and lactide crystal which was a decomposesd product adhered to the Pyrrx (registered trademark) test tube used in the 'test. The Mw and lactide content of the compositiion before and after tne heat stability test are shown in Table 2 and the L, a and b values are shoen. In Table 4.


100 parts by weighs of L-lactide and 0 .15 part by weight of atearyl alcohol were fed from the material feed porn of a polymerisation reactor equipped with a cooling distillation tube in a nitrogen stream. Subsequently; the inside of the reactor wa$ ©xijbstituted by nitrogen 5 times, and L-lactid.- wa.s molten at 190°C. when L-lactide was completely malten, 0.O5 part by weight of tin 2-ethylhexanoate was added from the material feed port



composition are shown in Table 5. The cbtainsd composition was ground with a griader to obtain grains as large a.s 2 to r mm, and 10 g of the grains was fed to a Pyrex (registered rrademark) test tube with a cock. Thereafter. the inside of the Pyrex (registered trademark) tesn tube was substituted by nitrogen to carry out a heat stability test at 260°C for 10 minutes and 60 minutes. After the end of the test, the composition was taken out to measure its Mw and lactide content. The meaeureTnent results are shown in Tables 5,


Comparative Example 3
A composition was obtained in the same manner as in Example 4 except that metaphosphoric acid was not added. A heat stability test was carried out on this composition in the same manner as in Example 4, The Mw, lactide conteut a-nd terminal carboxyl group amount of the obtained composition after the heat stability test are shown in Table 5.

Example 8 stereocomplex polylactide + netaphosphoric acid (manufacture of poly-L-lactide)
10 0 parts by weight of L-lactide and C . 15 part by weight of stearyl Alcohol were fed from the material feed port of a polymerization reactor equipped wir.h a cooling-distillation tube in a nitrogen stream. Subaequer.tly, the inside of the reactor was substituted by nitrogen 5 times, and L-lactidft wgig molten at 190°C. When L-lactide was completely molten, 0,05 part by weight of tin 2-ethylhexanoate was added from the material feed port
together with 500 ul of toluene to carry out polymerization at 190°C for 1 hour.
After the end of polymerisation, 0. 02 part by weight of metaphosphoric acid having a pH of an aquftouy solution prepared by dissolving 1 g thereof in 100 ml of water of D.85 was added from a catalyst injection port and knea.ded for 15 minutes. Finally; surplus L-lactide was volsLtilised and strand-like poly-L-lactide was discharged from, the discharge port of the reactor and pelletized while it was cooled, (manufacture of poly-D-lactide)


Finally, surplus D-lactide was volatilized and strand-like poly-D-lactide was disCharged frotn the discharge port of the reactor and pelletized while it was cooled, (formation of stereocomplexi
5 0 parts by weight of the above poly-L-lactide pellet and 50 parts by weight of the above poly-D-lactide pellet were mixed together well and kneaded together at 230°C in a nitrogen stream for 10 minutes ty using the 5 0C150 Labo Plastomill kneader of Toyo Seiki Co. , Ltd. The stereocomplex crystal content (X) of the obtained composition was 99.7 %. The Mw and lactide content of the obtained composition, are Shown in Table 6.

The measurement results are shown la Table 6*

Comparative Example 4
A composition was prepared in the $ame monner as in Example a except that the metaphosphoric acid-based deactivator was not added. The Mw, stereocotnplex crystal Content (x), lactide content and terminal carboxyl group amount ot the obtained composition are shown in Table 6. A heat stability test was made on the composition in the same manner as in Example 6. The measurement results are shown in Table 6.

Effect of the Invention
The composition of the present invention is excellent in heat stability, color and hydrolytic resistance. Therefore; even when it is heated, it rarely sxperiences a reduction in its molecular weight and keeps a good color. An increase in the lactide content of the composition of the present invention is very small even when it is heated.
That is, the compoeition of the present Invention hardly generates a lactide/ cyclic oligomer or chain low molecule in the step which requires heating at 180oC or higher such as melt spinning, melt film formation or injection molding.
Industrial Feasibility
The conposition of the present invention is useful as a raw material for fibers, films and molded articles.

CLAIMS
I. A compoition comprising (i) polylactide, (ii) a metal catalyst and (xii) a hypophoephoroue acid-based decictivator or A metaphosphoric acid-based deactivator.,
2 The composition according to claiin 1, wherein the
poLylactide is poly-L-lactide. poly-D-lactide or a mixture thereof.
3, The composition according to claim 1, wherein the pclylactide is a mixture of poly-L-lactide and pcly-D-lactide and, contains stereocompiex crystal,
4. The composition according to claim 1, wherein the metal catalyst is a compound containing an least one metal selected from the group consisting of an alkali earth metal, a rare eaxth element, a transition metal of the third period, aluminum, germanium, zin and antimony.
5 . The composition according to claim 1, which comprises 1.001 to 1 part by weight of the. metal catalyst based on IOC parts by weight of the polylactide-
The composition according to claim 1, wherein the hypophosphorous acid-based deactivator is at least one selected from the group consisting of hypophosphorous acid, an alkali metal salt of hypophosphorous acid, an alicali earth meta.l. salt of hypophosphorous acid and an onium salt of hypophosphorous acid.
7. The composition according to claim I, which comprises 1,001 no 5 parts by weight of the hypophosphorous acid-based deactivator based on 100 parts by weight of the polylactide,

8. The composition according to claim 1, wherein the
metaphosphorit acid-based deactivator is at least one
selected from the group consisting of a compound reprtsented
by the following formula., an alkali metal salt thereof, an
alkali earth netal salt thereof and an onium salt thereof:

9. The composition according to claim l, wherein the
metaphofiphoric acid-based deactivator has a pH of an aqueous
solution prepared oy dissolving i g thereof in 100 ml of water of a or less.
10. The composition according to claim 1, which comprises
0.001 to 10 parts by weight of the metaphosphoric acid-based
deactivator based on 100 parts by weigh of the polylactide.
11. A molded product of the composition of any one of claims
1 to 10.
12. A procese for manufacturing a composition containing
stereocomplex crystal by mixing poly-L-lactide and
poly-t-lactide, wherein at least one of poly-L-lactide and
poly-P-lactide contains a metal catalyst and the mixing is
carried out in the presence of a hypophosphorous acid-based
deactivator or a metaphosphoric acid-based deactivator.
13. The process according to claim 12, wherein the metal
catalyst is a compound containing at least one metal selected

from the group consisting of an alkali earth metal, a rare earth element, a tr&nsition metal of the third period, aluminum, germanium, tin and antimony-
14 , The process according to claim 12, wherein tha content of the metal catalyst is O.COl to 1 part by weight based on 10 0 parts by weight of the total of poly-L-lactide and
poly-D-lactide.
15. The procees according to claim 12, wherein the
hypophosphorous acid-bassd deactivator is at least one
selected from the group consisting of hypophosphorous acid,
an alJcali metal salt of hypophoephoroue acid, an alkali earth
metal salt of hypophosphorous acid and an onium salt of
hypophosphorous acid.
16. The process according to claim 12, wherein the
hypophosphorous acid-based deactivator is present in an
amount of 0,001 to 5 parts by weight based on 100 parts by
weight of the total of poly-L-lactide and poly-D-lactide,
17. The process according to claim 12, wherein the
metaphosphoric acid-based deactivator is at least one
selected from the group consisting of a compound represented
by the following formula, an alkali metal salt thereof, an
alkali earth metal salt thereof and an onium salt thereof:


18. The process according to claim 12, wherein the metaphoaphoric acid-based deactivator has a pH of an aqueous solution prepared by die solving 1 g thereof in 100 ml of water of. 6 or less.
15. The process according to claim 12, wherein the metaphoephoric acid-based deactivator is present in an amount of 0.001 to 10 parts by weight based on 100 parts by weight of the total of poly-L-lactide ard poly-D-iactide.