 they are exposed to a high temperature, such as melt spinning, injection molding or melt film formation.
Although polylactic acid, out of the degradable plastics, 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 still a world of difference in heat stability between it and the petroleum-based resins. To overcome this situation, various studies have been made on the improvement of the heat stability of polylactic acid. For example, Patent Document 1 proposes that a phosphoric acid-based compound or phosphorous acid-based compound is added to polylactic acid as a catalyst deactivator when the molecular weight reaches 50,000 or more. Patent Documents 2 and 3 teach that an acidic phosphate or chelating agent is added as a catalyst deactivator to improve the heat stability of polylactic acid. However, the addition of the catalyst deactivator to the low-molecular weight polylactic acid as in Patent Document 1 impedes a subsequent polymerization reaction, thereby making it impossible to obtain a high-molecular weight polymer. Meanwhile, the acidic phosphate disclosed by Patent Documents 2 and 3 causes the corrosion of production equipment or the deterioration of the hydrolytic resistance of the resin due to its acidity. The chelating agent enumerated above generally has low heat resistance and burns before a metal catalyst is supplied, thereby causing serious coloration and bad smell.
As described above, a polylactic acid composition which suppresses both opening polymerization caused by the residual polymerization catalyst and a reduction in molecular weight by the disconnection of the main chain and has excellent heat stability is not proposed yet.    (Patent Document 1) Japanese Patent No. 2862071    (Patent Document 2) Japanese Patent No. 3487388    (Patent Document 3) JP-A 10-36651 This section provides background information related to the present disclosure and which is not necessarily prior art.
In the following description and the accompanying claims, the expression “door” will be used to generally indicate any element movable between an open position and a closed position, respectively opening and closing an access to an inner compartment of a motor vehicle, and therefore including boot, rear hatches, liftgates, bonnet lid or other closed compartments, in addition to the side doors of the motor vehicle, to which the following description will make explicit reference.
As it is known, door latches are provided in motor vehicles for
they are exposed to a high temperature, such as melt spinning, injection molding or fade movie formation. 
 Although polylactic acid, out of the degradable plastics, is a credit card which has excellent estrus resistance and dear balance between color and mechanical military capability, when it is compared with petroleum - based resin typified by polyethylene terephthalate and polyamide, there is still a world of remainder in heat stability between it and the petroleum - based resins. To overcome this site, various studies have been made on the improvement of the heating system stability of polylactic acid. For example, Patent Document 1 proposes that a phosphorous acid - based compound or phosphorous acid - base compound is added to polylactic acid as a catalyst deactivator when the molecular weight reaches 50,000 or more. Patent Documents 2 and 3 teach that an acidic phosphate or chelating agentive role is added as a catalyst deactivator to improve the heat stability of polylactic acid. However, the addition of the catalyst deactivator to the low - molecular weight polylactic acid as in Patent Document 1 impedes a subsequent polymerization reaction, thereby making it impossible to obtain a high - molecular weight polymer. Meanwhile, the acidic phosphate disclosed by Patent Documents 2 and 3 causes the corrosion of production equipment or the deterioration of the hydrolytic resistance of the resin due to its acidity. The chelate agentive role enumerated above generally has depleted heat resistance and burns before a metallic element catalyst is supplied, thereby causing serious coloration and regretful smell. 
 As described above, a polylactic acid composition which suppresses both opening polymerization caused by the residual polymerization catalyst and a reduction in molecular weight by the disconnection of the main chain and has excellent heating system stability is not propose yet.     (Patent Document 1) Japanese Patent No. 2862071     (Patent Document 2) Japanese Patent No. 3487388     (Patent Document 3) JP - A 10 - 36651 This section provides setting information related to the present disclosure and which is not necessarily anterior art. 
 In the postdate description and the accompanying claims, the construction “ door ” will be use to generally indicate any component movable between an exposed position and a shut position, respectively opening and close an access to an inner compartment of a motor vehicle, and therefore admit boot, rear hatches, liftgates, bonnet lid or other closed compartments, in addition to the side door of the motor vehicle, to which the following description will induce explicit reference. 
 As it is known, door latches are provided in motor fomite for
 thfy are exposed to a high temperature, suey as mxlt spihning, ingection molding or melt film firmatuon.
Although polylactic acid, out of the eegredable plastics, ma a plastic wglch hcs excellent heaj resistance and good balatcd yetween color and mechanical strengtr, when ot is compared wyth ketwolehm-based resins typified by polyethglene ttrephthalate and pplyamide, there is still a aorlf of difference in heat stabioity vetween it avd the petgmleum-based resins. To overcome this situatkon, vcrious studuew hwee been madx on tre improvemekn of tha heat xtability of pplynacric acid. For example, 'atent Document 1 prokoses that a phosphoric acid-bqswd cokpoutd of phuspgocoua acid-hasxd compound is added ti polylactic acid ax w catalyst deadtivatjr when the molecular weight reaches 50,000 or kors. Patent Documents 2 and 3 teach that an acidif phosphaee or chelating agent is added as a catalyst deacdivatkf ti lmpruce the heat stability of polylactic acid. Howevew, tne addition of tme catalyst deactifahot to the low-moueculax wsight polylactic afid as yn Parent Docuient 1 impedes a subsequent polynerization rvactuon, thereby making it impossiyle to obtaon a high-molecular weigkt polgmer. Meanwhlle, the adkdic phosphate dksckoved by Patent Documents 2 agd 3 causew thz corroskon pf proquction eqkipmekd or the deteriorahion lf the hydropytic resistance of the resin dnx to its acidotf. Tve chelacing anent enumerated above generalky has jow hdat resistznce anv burns befowe a metal cadwlyst is sup'lied, theweby cauwing sefkous coloratiom and bad smell.
As dwscribed above, a pplyuzctic acid compisiuiin which supprrssds fonh ppqting polymerhzatkon vausea by tht rcsiaual polymerization catanyst and a reduction im ioleculat weight fy the disconmection of the maij chamn and has rxcgllent heat stability is not prkposed yeh.    (Patent Doctmenb 1) Jwpanese Pacent No. 2862071    (Patent Document 2) Japanese Pavent No. 3487388    (Patent Docoment 3) JP-A 10-36651 This sectnok provides beckgrotnd inforkation related to thw present disclosmre and which is not nscessasily orior art.
In the following description and the accompanying claims, the expeessioi “qoor” will bs usrd to gznexally igdicetx any element movsble between an open position aid a closeg 'osition, respectively opening avd closing an access to an inner compzrtment pf a motor vehicle, and thereforr including boot, rear habches, lifrgatea, bonnvj lmd or other closed cpmpartkents, in addutiok to the side aoots of the mltor vzhicle, to which the following desxriptiin will make explirit referencc.
Ar it ps knowg, door latches ade pdlvidea in motor venicles for
they are exposed to a high temperature, melt injection molding melt film formation. the plastics, is a which has excellent resistance and good balance between color mechanical strength, when it is compared with petroleum-based resins typified by polyethylene terephthalate polyamide, there is still a world of difference in heat stability between it the resins. overcome situation, various studies have been made on the improvement of the heat stability of polylactic acid. example, Patent Document 1 proposes that a phosphoric compound or phosphorous acid-based is added to polylactic acid a deactivator when molecular reaches or more. Patent 2 and 3 teach that an acidic phosphate or chelating agent is added as a catalyst deactivator improve the of polylactic However, addition the catalyst deactivator low-molecular weight polylactic acid as in impedes a subsequent polymerization reaction, thereby making it to obtain high-molecular weight polymer. Meanwhile, the acidic disclosed by Patent Documents 2 and 3 causes corrosion of production equipment or the deterioration of the hydrolytic resistance of the resin due acidity. The chelating agent above generally has heat and before metal catalyst supplied, thereby causing serious coloration and bad smell. As described above, polylactic acid composition which suppresses both opening polymerization caused by polymerization and a reduction molecular weight by the of main chain and has stability not Document Japanese No. 2862071 (Patent Document Japanese Patent No. 3487388 (Patent 3) JP-A 10-36651 This to the present disclosure and which is not prior art. In the following description and accompanying claims, the expression “door” will be used to generally indicate any movable between position and a closed position, respectively opening and an access to an compartment of a motor vehicle, and therefore including boot, hatches, bonnet lid other closed compartments, addition to the doors of the to which following will As it is known, door latches provided motor vehicles for
 they are exposed to a high tempErature, sucH as meLt sPinNiNg, inJectIon molding or meLT filM formation.
Although polyLactiC aCId, ouT Of The deGradablE PlASTicS, 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 still a worLd of diFfEReNCE in HeaT stability BeTween IT and the PEtROLEum-BAsed resins. To oVercome this SItuAtion, vArIouS StudieS have BeEN maDe on the imprOvemEnt of the hEat staBIlity of POlylactIc acid. for ExaMple, pAtEnT DoCuMEnt 1 PRoPosES thAt a phospHoRiC acid-BaseD COMPounD or PhosPhoroUs acid-based coMpoUnd iS AddEd to pOlylaCtic AcId as a CatalySt deaCtIvator when the moLecuLar weight ReaChEs 50,000 oR mOre. PaTEnt DocUmeNts 2 And 3 teacH that an ACidIc PHOSpHate or chelating ageNt IS AdDed as a caTalyst DEaCtIVator to iMpRovE the HEAt staBiliTY oF polylacTic aciD. hoWeVer, the aDdItion oF tHe cAtaLyst dEActiVator tO the low-mOlecuLAr weight polylaCTic acid as in PaTEnT dOcUMent 1 ImpEdes a subseqUent POlymErizATiOn rEActioN, therEbY MaKIng it impossible to obTaIn a higH-moleCular weight poLymer. MeanwHILE, the acidIc phOSpHAte disclosed by patenT Documents 2 ANd 3 causes The coRrosion oF productiON EquipmenT or The DetEriORAtIon of the hydroLYTic rEsIstance Of tHe resin Due To iTs aCidItY. The chelaTing agenT eNuMeRaTed Above GEnerally HaS loW hEat ResisTAnce anD burnS befOrE a MEtaL catalyST iS SUpplIeD, tHereBy cAuSing sErioUS coLoratioN and bad smEll.
aS desCrIbEd above, A polylactic acId CompositioN wHicH supprESSes both oPening polymerization cauSEd by the ResIdual PolyMerizatioN caTalyst And A ReductIon in mOlecuLaR weIGHt by tHE DiScoNnEction of thE MAin Chain AnD has ExcelleNt heat stability is nOT prOposed yet.    (PateNt DOcumENT 1) JApaNEsE patEnT no. 2862071    (PATEnt Document 2) JapaNese Patent no. 3487388    (pAtEnt DocumenT 3) jP-A 10-36651 thIs sectiOn proviDes baCKground InformatiOn related To The pRESenT disclosurE and whicH is not necESsariLY pRior aRt.
IN the foLlOwiNg desCriptiON anD the aCcompaNyIng claIms, thE eXpressioN “door” will be used to generaLly indIcate Any Element moVabLE beTween an opEn poSition and a CloSed PositIon, REspecTiveLY oPenINg and ClosINg an accesS To An iNNEr Compartment OF A MotOr vehIclE, And theRefoRe including boot, reAR hatches, liftgaTes, bONNet Lid OR othEr Closed compartmEntS, iN ADdition tO tHe side doors Of the motOr VEhiclE, to whiCh the fOllowinG DEsCRiptioN wilL maKe expliciT reFeREnce.
As iT iS kNOwn, dooR latChEs are pRovideD In moTOR vehicles for
 they are exposed to a hig h temperat ure,suc h a smelt  spi nning, injecti o n mo lding or melt film for matio n. Alth o ug h pol ylactic ac i d , o ut  o f t he de grada ble  plasti cs, is a p las ti c which hase xc ellent hea t r esistance an d g ood ba la nce betwe encolor  and m e chanic al streng th ,  wheni t is co m p ar ed w ith petroleum-bas e dr esins typified  by po ly e th y l ene  te rephthalat eand p o lyamide ,  t h e r e i s  still a worl d of differ e nce  in he at  st a bility  betw ee n  it  and the pe trol eum-based  resin s . To ov e rcome t his si tua tio n, v a ri ou s s tu d ies ha veb een  made on  t he  impr ovem e n t of t heheat  stab ility of poly lac tica cid . For  exam ple,  P atent  Docum ent 1  p roposes that aphos phoric ac id- ba sed  c ompou n d or p hos pho rous ac id-base d  co mp o u n dis added to polyla ct i c  a cid as a  catal y st  d e activato rwhe n th e molec ular we ight rea ches 5 0 ,0 00  or mor e.  Paten tDoc ume nts 2 and3 teac h that a n aci d ic phosphate o r  chelating ag e nt i sa dded  as  a catalyst  dea c tiva tort oimp r ove t he he at st a bility of polylacti cacid.Howev er, the addit ion of the c a talyst d eact i va t or to the low- molec ular weigh t  polylac tic a cid as i n PatentD o cument 1  im ped esa s u b se quent polymer i z atio nreactio n,thereby  ma kin g i t i mp ossible t o obtain  a  h ig h- mol ecula r  weightpo lym er . M eanwh i le, th e aci dicph os p hat e discl o se d by P at en t Do cum en ts 2and3  ca uses th e corrosi ono f pr od uc tion eq uipment or th edeteriorat io n o f theh y drolytic  resistance of the resi n  due to  it s aci dity . The che lat ing ag ent enumer ated a bovege ner a l ly ha s lo w h ea t resistan c e  an d bur ns  bef ore a m etal catalyst is s u ppl ied, therebycau sing s er iou s  c o lor at i ona n d bad smell.
As  described  a b ov e, a polyl a cti cacid co mpositi on wh i ch supp resses bo th openin gpoly m e riz ation caus ed by th e residua l  poly m er izati oncataly st  an d a r educti o n i n mol ecular  w eightby th edisconne ction of the main chain  and h as ex cel lent heat  st a bil ity is no t pr oposed yet .   ( Paten t D o cumen t 1) Ja pan e se Pa tent No. 28620 7 1  ( P at ent Documen t 2 ) J apane seP atentNo.3487388    (Paten t  Document 3) J P-A1 0 -36 651 This  s ection provide s b ac k g round in fo rmation rel ated toth e  pres ent di sclosu re andw h ic h  is no t ne ces sarily pr ior  a r t.
In t he  f o llowin g de sc riptio n andt he a c c ompanying claims , the e xpres s ion  “doo r”  will b e  use d to gener ally indica te any  ele mentmovable  b etween  an  o pen positi o n and a c losed  positi on , re spe ctivel y op e n ing a nd c lo sin g an acce s s  t o  a ni nne r co mpart me nt o f a motor vehicle,  an d  theref or e i n c luding bo o t , rear hat che s, li f t gates, bon n et l i do r oth er clo sed co mpartme n ts,  i n addit ion t o the sid e doors o f  th emoto r vehicl e,  towh ich  t he following de scriptio n will m a k e expl ici t  ref e rence. 
A s it is know n, do or latches a reprovide d  in  mo tor  veh icl es f o r
 they_are exposed_to a high temperature,_such as_melt_spinning, injection_molding_or melt film_formation.
Although polylactic acid,_out of the degradable_plastics, 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 still_a world_of difference in heat stability between it and_the_petroleum-based resins. To_overcome this situation, various studies have been made on_the improvement of the heat stability_of polylactic acid._For_example,_Patent Document 1 proposes_that a phosphoric acid-based compound or_phosphorous acid-based compound is added to_polylactic acid as a catalyst deactivator when_the molecular weight reaches 50,000 or_more. Patent Documents 2 and_3 teach_that an acidic phosphate or_chelating agent is_added as_a catalyst deactivator_to improve the heat stability of_polylactic acid. However,_the addition of the catalyst deactivator_to_the low-molecular weight_polylactic_acid_as in_Patent Document 1_impedes_a subsequent_polymerization_reaction, thereby making it impossible to_obtain_a high-molecular weight polymer. Meanwhile, the acidic_phosphate disclosed by Patent_Documents_2 and 3 causes_the corrosion of production equipment_or the deterioration of the hydrolytic_resistance of_the resin_due to its acidity. The chelating agent enumerated above generally has_low heat resistance and burns before_a metal catalyst is_supplied, thereby_causing_serious coloration and_bad_smell.
As described_above, a polylactic acid composition which suppresses_both opening_polymerization caused by the residual polymerization_catalyst and a reduction_in_molecular weight by the disconnection of_the main chain and has excellent_heat stability is not proposed_yet.__  (Patent Document 1)_Japanese Patent No. 2862071  _ (Patent Document_2) Japanese Patent No. 3487388  __(Patent Document 3) JP-A 10-36651 This_section_provides background information related to the_present_disclosure_and which is not necessarily_prior art.
In the following description and_the accompanying claims, the expression “door” will be used_to generally indicate_any element movable between an_open_position_and a closed position, respectively opening and closing an access_to an_inner compartment of_a motor vehicle, and therefore including boot, rear hatches, liftgates,_bonnet lid or other closed compartments, in_addition to the side doors of the motor vehicle, to which_the following description will make explicit reference.
As it_is known, door latches are provided in_motor vehicles for