CA2056549A1 - Continuous lactide polymerization - Google Patents
Continuous lactide polymerizationInfo
- Publication number
- CA2056549A1 CA2056549A1 CA002056549A CA2056549A CA2056549A1 CA 2056549 A1 CA2056549 A1 CA 2056549A1 CA 002056549 A CA002056549 A CA 002056549A CA 2056549 A CA2056549 A CA 2056549A CA 2056549 A1 CA2056549 A1 CA 2056549A1
- Authority
- CA
- Canada
- Prior art keywords
- process according
- reactor
- catalyst
- monomers
- operated
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/24—Stationary reactors without moving elements inside
- B01J19/245—Stationary reactors without moving elements inside placed in series
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
- C08G63/06—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from hydroxycarboxylic acids
- C08G63/08—Lactones or lactides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/00049—Controlling or regulating processes
- B01J2219/00051—Controlling the temperature
- B01J2219/00074—Controlling the temperature by indirect heating or cooling employing heat exchange fluids
- B01J2219/00087—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements outside the reactor
- B01J2219/00094—Jackets
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/00049—Controlling or regulating processes
- B01J2219/00051—Controlling the temperature
- B01J2219/00132—Controlling the temperature using electric heating or cooling elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/00049—Controlling or regulating processes
- B01J2219/00051—Controlling the temperature
- B01J2219/00159—Controlling the temperature controlling multiple zones along the direction of flow, e.g. pre-heating and after-cooling
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Polyesters Or Polycarbonates (AREA)
Abstract
CONTINUOUS LACTIDE POLYMERIZATION
ABSTRACT OF TEE DISCLOSURE
Lactide monomers and copolymers may be polymerized by a continuous process using one or more continuous stirred tank reactors. The process offers productivity and product quality advantages over the batch process of polymerization.
ABSTRACT OF TEE DISCLOSURE
Lactide monomers and copolymers may be polymerized by a continuous process using one or more continuous stirred tank reactors. The process offers productivity and product quality advantages over the batch process of polymerization.
Description
~ .~k~
~; ;~ ;65 FIELD Oli' T~ TION
The present invention relates to the manufacture of polymers of l, d, cll or meso lactides. More particularly the present invention relates to a process for the continuous production of such polymers.
BA~KGROUND OF TE~E INVENTION
0 Canadian patent ~08,731 issued March 18, 1969 to Ethicon Inc. disclosesa process for the formation of polylactides using a catalyst of the formula RlMR2 wherein Rl and R2 are hydrocarbyl groups having from 1 to 12 atoms and M is a divalent metal of Group II of the periodic table. The patent teacllesthat the polymerization may be carried out as a bulk polymerization. However, the patent does not disclose a continuous process. Rather the process is a batch2 o process.
WO 90/01521 (PCT/US89/03380) application in ~he name of Batelle Memorial Institute discloses a degradable thermoplastic made from lactides.
The disclosure teaches at page 19, that the polymerization process may be conducted in a batch, semi-continuous or continuous manner. However, no further details of a continuous process are disclosed and all the examples ~Ise batch process. The disclosure does not suggest a process using a chain of one preferably two or more reactors in series. The Batelle patent application giYes an extensive ~iscussion of the prior art and no prior art seems to contemplate acontinuous reaction using a chain at least one, preferably two or more re~ctors in series. -. f , . ., , , , . . , . , ,. , ., , . , ,... . . .. . . . -- . . , : , -.. , . , . . . . .. , . - . . . ., . "..... . ..
,, :, . :, - .. . . .. . . .... . . .
- ~ . . . , , , . , . . ,: . .
: , . . ,- ' ' . - ' ' '.'. . .
The present seeks to provide a novel process :~or the continuous polymerization of polylactides in which one, preferably a chain of at least two reactors in series is used.
SIJMMARY OF THE INVENTION
The present invent;on provides a continuous process for the polymerization of monomeric mixture comprising from 100 to 60 weight % of one or more monomers the formula T2 ~o R1 C~
o o ~ `
~C C R
O R2 . ' wherein R~ is a hydrogen atom or a Cl 4 alkyl radical; and R2 is a hydrogen :~
atom or a Cl 8 alkyl radical, provided that Rl and R2 cannot both be a hydrogen atom; and 0-40 weight % of one or more copolymerizable monomers which 30 comprises:
(a) forming a melt or solution of said monomers;
(b) passing said monomeric melt or solution through at least one reactors operated at temperatures from 150 to 250C and at a pressure rang;ng from 0.5 to 5 atmospheres at a rate and for a period of time to provicle .,:, , ~ -, - , . . , : ' , , ,~ . : . , , , .. , , , , -, , . , , , , . , , , . ~ , . . ~ . , "
.: ~ -2U~ii6549 not less than 75 % conversion of said monomer mixture to polymer. - -DET~ILED DE~RIPTI~N
Figure 1 is a schematic drawing of a reactor system which may be ~Isec in accordance with the present invention.
The monomers of Formula I useful in accordance with the present 10 invention may be obtained from a number of sources. Preferably the monomer is obtained from the fermentation of a relatively inexpensive feed stock s~lch as starch derived from sugar(s) etc. However, it should be borne in mind that generally such procedures result in a racemic mixture of the d, and l, monomer and the polymerization of such a mixture will result in a polymer having a relatively low level of crystallinity. Preferably the monomers will be selectecl ~o to provide higher crystallinity polymers comprising a relatively grater amoullt, preferably at least 75 more preferably at least 85 weight % of the 1, monomer and up to about 25 preferably less than 15 weight % of the d monomer. Such a blend of monomers should also provide relatively higher melting polymers, having a melting temperature in the range from 130 to 170~. However, other mixtures of the monomers may be used ;f melting temperature is not a 30 significant concern as would be the case for example in blister packaging.
A particularly usefill monomer of Formula 1 may be a lactide, that is a alpha hydroxy lactic acid. Suitable monomers of Formula 1 also inclucle may be a Cl-8 alkyl ester of lactide. Switable copolymerizable monomers include cyclic C24 alkylene oxides such as polypropylene oxide. Other f~mctional :
; , - - , . . . . . . . ... . . . . . .
. . ;.: . .. ..
, , : ' ~
X~s6S4~
monomers may be included in the monomeric mixture provided they will not significantly hydrolyse the resulting polymer. Preferably, the copolymeriz~ble monomers will be esters.
The monomeric mixture may comprise 100 weight % of one or more monomers of Formula 1. Preferably, the mixture will comprise from 100 to 65 more preferably 100 to 85 weight % of one or more monomers oiF Formula I, and from 0 to 35 preferably not more than about 15 weight % of one or more copolymerizable monomers.
The present invention will now be described in association with Figure l in which like parts have like numbers.
The monomers are fed into a prereactor 1 which is a heated vessel. The 20 vessel may be heated by o;l or steam or pressurized water maintained at initi~l temperature Tl. The vessel is heated to above the melting point of the monomer mixture to be polymerized. Typically the temperature will be from about 125 to 150C. The monomers may be fed to the prereactor in dry form or may be in the form of a solution or suspension. If the monomers are in the form of a solution the concentration of monomers in solvent or diluent should 30 be as high as practicable, and preferably not less than about 85 % by weight.
There are a number of suitable diluents or solvents including C6 ,~ aromatic solvents, C6 ~2 alkanes which are unsubstituted or substituted by a Cl 4 alkyl radical, and Cl 6 alkyl ketones. Suitable aromatic diluents include ethyl benzene and toluene. Suitable C6 ,2 alkanes include hexane and ethyl hexane. Suitable . ~ ,. . . . .
. . ' .. :: ~ . : ............................... ~ :
~ ~ ";," ' ",,.., , ': ' '.
,~
X~565~g C1-6 ketones include acetone. The prereactor is joined to the first reactor by aheated line 2 maintained at constant temperature. The monomer melt is pumpecl to the first reactor 4 by pump 3. The pump is also heated to maintain a constant temperature of at least Tl. The heating means on the pump 3 and line 2, may be any suitable means such as an electric heating line steam line or lloto oil and preferably controlled independently.
In an alternate embodiment the lactide monomer may also be deliverecl directly to the first reactor using a dry bulk feed apparatus. Such as approach -is of greater simplicity as it replaces the pre-reactor, metering pumps, associated lines, heating equ;pment and controls, with a simple self-containecl unheated device. In addition such a feed device provides a simple process to 20 stop the process without compromising monomer feed which otherwise would be in a melt. However, it should be noted that such a feed device should be equipped with water cooling capability to avoid premature melting of incoming monomer. Premature melting could lead to monomer feed blockage.
~ eactor 1 and also the subsequent reactors may typically be a stirred vessel, such as a continuous stirred tank reactor, capable of operating at 30 reduced and elevated pressure and temperatures up to about 250C. The reactor configuration may be spherical, cylindrical or tubular. The agitator may be of any suitable type for the reactor including turb;ne, anchor, paddles and screw conveyor, or comb;nations thereof, such as an ax;al flow turb;ne in combination w;th peripheral anchor(s) or anchors in comb;nation with peripheral a single or : - : . . . -.
~ ~ ~ . - . .. . . .
-, . . . . . . . . . . .
."...... ,. . , . . , . : . . : : :
', ' .'''~' '', ' ' ', '. .'' ;.' .' ' . ~
2~S~5~9 double helix r;bbon.
In a preferred, optional, embodiment a catalyst is used to increase the rate of reaction. A wide range of catalysts are suitable to promote the rate of the reaction. The catalyst may be an acid cation exchange resin, acid clay, activated clay, bentonite, alumina, or an aluminurn complex of the formula lO Al(O-R)3 where R is a C~.6 alkyl radical, talc, silicic acid, metal complexes of the formula RlMR2 wherein R~ and R2 independently may be selected from the group consisting of C"~, preferably a Cs lo carboxy radicals, an oxygen atom, a halogen atom,and M is a Group II or IV metal atom. Preferably, M is selected from the group consisting of magnesium, calcium, tin and lead. Preferably, R, and R2 are the same and are Cs lo carboxyl radicals. Particularly useful 20 catalysts include stannous octoate and the aluminum complex Al (O-R)3. S~lch aluminum complexes are disclosed in H. R. Dricheldorf Macromolecules Vol.
21, No. 2 p. 286 (1988).
The catalyst may be added to the first and/or any subsequent reactor. ln the drawing a catalyst vessel is shown at 5. The catalyst may be used as a dilute solution or suspension. However, preferably the catalyst is used in 30 undilute form. The catalyst vessel is connectecl to the first reactor by a line 6 and a pump 7. As noted-above, the catalyst vessel need not be only connectecl to the first reactor. It may be connected t~ one or more subsequent reactors.
The monomers and optionally catalyst are fed to the first reactor 4. The first reactor 4 has a jacket 8 which may be heated by steam or hot oil or , . .
. . . . . .
' . , , ' ~ '' ' ' ,' .: , , . . .
:; : ' . ' , ,~ .
` ; ' " " ` : `. -' . , `:
.'` ' . ' ' 2~S65~9 pressurized hot water to a temperature T3. The reactor is operated at temperatures from about lS0 to 225, preferably from 175 to 200, most pre~erably about 175C and at a pressure from about 0.5 to 5.0, preferably about 1.0 atmospheres pressure. Typically, the reactor is a stirred tank reactor.
That is there is agitation in the reactor using typical systems as described above.
The monomers and optional catalyst are kept in the first reactor for a period of time to permit a conversion from about 35 to 85 % depending on the number of reactors in the chain. Typically the conversion of monomer to polymer coming out of the first reactor should be from about 50 to 80%. The residence time in the first reactor should be from 1 to 3 hours depend;ng on thesize of the reactor and the rate of feed to the reactor. ;~The polymer melt is pumped from the first reactor to the second reactor 9 by a pump 10 through a heated or insulated line 17 maintain at T3. The second reactor, like the first reactor also has a jacket 11 and is maintained atT4. The second reactor is operated at temperatures from lS0 to about 250, most pre~erably from about 185 to 200C.
The polymer melt is held in the second reactor for a period of time from - -about 1 to 3 hours to bring the conversion up to from about 75 to 95, most preferably from 90 to 95% .
The polymer melt is then pumped from the second reactor by a pump 12.
In the embodiment shown in the drawing the polymer melt is pumped througll line 13 to reactor (or preheated) 14. The reactor is preferably a t~lbe shell type ., . ~ . . , . ~ ,.... . ..
: ................. . " . . . . . . ... . . .
. . -. . . . , . , ... : , .. :, ..
; , :, -, , , .. . , .. . ~ ; .. . ..
. .: ., ... ~ . ., .. .: - .
, . . . ~ , .... . ... . . ..
,, ,, " , . .: .. : . . . .
~Q56Sfi9 heat exchanger. Reactor 3 rnay comprise a single pass tul~e in shell heat exchanger with static mixers for a more uniform product; or an extruder-type device if additional pressure is required. The shell enclosing the tubes thro~lgh which the polymer melt passes is heated and maintained at a temperature of T3 using suitable heating means such as electric heaters, hot oil, water or steam.
o The preheater is heated to temperatures up to about 250C. More typically the preheater will be heated to from about 180 to 210 preferably froln190 to 200, most preferably about 200C. The residence time of the polymer melt in the preheater may range from about 5 to 15 minutes. Preferably the time is kept a short as possible to minimize polymer degradation and/or depolymerization. The pressure in the preheater should range from abo~lt 0.1 to 1.5 typically about 0.5 atmospheres.
Generally, the polymer melt e~its the preheater directly into the upper end of devolatilizer 15. The devolatilizer is operated at a temperature T6 from about 150 up to about 225, preferably from about 200 to 220C. The internal pressure in the devolatilizer is below atmospheric, typically less than abo~lt 0.02, most preferably less than about 0.01 most preferably less than about 0.005 atmospheres. While the embodiment in Figure 1 shows only one devolatilizer the devolatilizer may comprise a series of two devolatilizers as are disclosed in a mlmber of patents in the name of Monsanto. The devolatilizer may be a falling strand devolatilizer. That is the polymer melt falls as strandsfrom the top to the bottom of the devolatilizer. As the polymer descends to the g ~,- , , - . . . :
:. . -, ,, . ~ . . ~ . .
. - . . . . . . . . . . .
, . . . . . .
. .
. .. , .. : , .. , . - .- ., . . , . . .:: . .
.. . .. : . . . . . :, , . - . . . . .
:, . . , , . ~ .
., ,. .. . . . , ~ . :
. . , . . , .
2QS654~
bottom of the clevolatilizer the unreacted monomer and diluent evaporate from the polymer and are withdrawn from the devolatilizer. Depending on the polyrner viscosity and the level of unreacted monomer polymer distributors may be used. For e~cample, the polymer melt could be held in a sub atmospheric chamber for longer periods of times by using a buffer or catcher tray, such as o those disclosed in U.S. Patent application 271,636 in the name of Polysar Financial Services S.A. A further alternative could be to use an extruder type devolatilizer equipped with a single or multi-stage vacuum apparatus to ach;eve ~ -vacuum levels as low as 0.002 atmospheres. Also a suitable carrier solvent such as nitrogen, toluene, ethyl benzene etc., may be used as a nucleating agent and to aid in reducing the partial pressure of unreacted lactide monomer. This would be beneficial in trying to reduce the final level of lactide monomer in the finished product.
Yet another approach could be to use thin film (wiped-film) evaporators where the combination of shorter dwell times, high ratios of surface area to volume and reduced shear rate is of benef~t to the properties of the finished product.
The volatiles from the devolatilizer pass to a condenser 16. The condenser may comprise one or more stages or zones at different temperatllres to more completely condense the volatiles and to poss;bly separate the volatiles into dif~erent fractions. The separation may also be achieved by using thin film separators and by chang;ng or increasing the amount of carrier diluent or .... . - ,. .. , ... , , , .. , , . :. .,.. ,, : ... , , . ., . .,: . .
.. . .. , ,... , , : . .:: .. , - : . :
. .. . . . . . .. . . .
.: . ." :. ,. . : . .. .. .. . .
.. . . . . . ...
; . :. ,.. .,, - , . .. , :
.. . . . . . . . .
2~S6~49 solvent.
The resulting polymer may then extruded as strands and cooled ancl chopped into pellets which then may be moulded, extruded, blown or thermoformed into various articles.
The polymer resulting from the process of the present invention sho~lld o have an intrinsic viscosity from about 0.5 to about 2.5 indicating a molec~llar weight from about 50,000 to about 300,000.
The process of the present invention has been described in association with two reactors. However, the chain could comprise from two to five, more typically two to three reactors.
The present invention will now be illustrated by the -following non-20 limiting example in which unless otherwise indicated parts are parts by weight.
Example 1 A continuous polymerization of l-lactide was carried out using a pilot plant having a single CSTR reactor in a layout as in Figure 1. Af!ter reaching steady state in about 7 hours, the monomer was melted in a p~erea,ctor and fed into the reactor at a rate of 10 lb/hr. The reactor was operated atll78C. The 30 reactor was a stirred tank reactor. A catalyst comprising stanno~ls 2-ethyl hexanoate was fed to reactor at a rate of 1-1.5 g./hr. Dlle to a mechanical problem the catalyst feed was 0.1% based on monomer. The target feed was 0.65~ based on monomer. As a result the molecular weight of the resulting laGtide polymer was low. The residence time in the first reactor was about 4 .. . , ~ . ... . . . . .
. , . ~ . " , , , ., ., : . . ., . . . . :. ~ ..
- . .. - , . . . ..
: . , .- .. ,. ~ . .. .. . . ..
.. . . .
, . . . . .. . . . . . . .
.: . . - ., ",.. ,: . . . . .
. . .
hours. The conversion in the reactor after reaching steady state was from 95.5 to 96%.
Due to the problem with catalyst feed the product exiting the reactor was sampled and conversion (gravimetric in an oven) was determined. As indicatecl the conversion was constant. The other variables including temperature, RPM
o of the stirrer, etc. remained essentially constant, with in experimental error given the continuous nature of the process. The conversion result during start-up and while running are set forth in Table 1.
.
.
. .
.. . . .
,.. .
.
2~5~i5 Contimlolls Bulk Polylactide Proc~ss ¦ DATE TIMEConversion % SOL~DS (Oven method) I~
12/12/90_ 09:50 54.1 12/12/9010:50 97.1 0 12/12/9011:50 93.6 12/12/9012:50 92.5 _ 12/12/9013:50 92.9 12/12/90 16.45 _ 96.8 12/12/90 18: 15 95.3 l _ _ I
12/12/90 21 :50 96.1 12/13/90 _ 00:50 96.8 12/13/9û 04:50 96.8 12/13/90 09:55 89.~ (*) 12/13/90 12:00 95.5 Onset of ~ontinuous Operation: 17:00 hours on 12/12 End of Continuous Operation: 13:30 hours on 12/13 TOT~L Continuous Operation: 20:50 hours ~*) sample degraded during oven test.
The results show that lactide polymer may be produced by a continuous process.
,:
- ,, , , ; , , . , , ., ~ ., . ~ ,: , :
:' ' - " ' ' . ' , : - ' ~ , . . ''. ::' '~
-: : , . . . . . . .
.
~; ;~ ;65 FIELD Oli' T~ TION
The present invention relates to the manufacture of polymers of l, d, cll or meso lactides. More particularly the present invention relates to a process for the continuous production of such polymers.
BA~KGROUND OF TE~E INVENTION
0 Canadian patent ~08,731 issued March 18, 1969 to Ethicon Inc. disclosesa process for the formation of polylactides using a catalyst of the formula RlMR2 wherein Rl and R2 are hydrocarbyl groups having from 1 to 12 atoms and M is a divalent metal of Group II of the periodic table. The patent teacllesthat the polymerization may be carried out as a bulk polymerization. However, the patent does not disclose a continuous process. Rather the process is a batch2 o process.
WO 90/01521 (PCT/US89/03380) application in ~he name of Batelle Memorial Institute discloses a degradable thermoplastic made from lactides.
The disclosure teaches at page 19, that the polymerization process may be conducted in a batch, semi-continuous or continuous manner. However, no further details of a continuous process are disclosed and all the examples ~Ise batch process. The disclosure does not suggest a process using a chain of one preferably two or more reactors in series. The Batelle patent application giYes an extensive ~iscussion of the prior art and no prior art seems to contemplate acontinuous reaction using a chain at least one, preferably two or more re~ctors in series. -. f , . ., , , , . . , . , ,. , ., , . , ,... . . .. . . . -- . . , : , -.. , . , . . . . .. , . - . . . ., . "..... . ..
,, :, . :, - .. . . .. . . .... . . .
- ~ . . . , , , . , . . ,: . .
: , . . ,- ' ' . - ' ' '.'. . .
The present seeks to provide a novel process :~or the continuous polymerization of polylactides in which one, preferably a chain of at least two reactors in series is used.
SIJMMARY OF THE INVENTION
The present invent;on provides a continuous process for the polymerization of monomeric mixture comprising from 100 to 60 weight % of one or more monomers the formula T2 ~o R1 C~
o o ~ `
~C C R
O R2 . ' wherein R~ is a hydrogen atom or a Cl 4 alkyl radical; and R2 is a hydrogen :~
atom or a Cl 8 alkyl radical, provided that Rl and R2 cannot both be a hydrogen atom; and 0-40 weight % of one or more copolymerizable monomers which 30 comprises:
(a) forming a melt or solution of said monomers;
(b) passing said monomeric melt or solution through at least one reactors operated at temperatures from 150 to 250C and at a pressure rang;ng from 0.5 to 5 atmospheres at a rate and for a period of time to provicle .,:, , ~ -, - , . . , : ' , , ,~ . : . , , , .. , , , , -, , . , , , , . , , , . ~ , . . ~ . , "
.: ~ -2U~ii6549 not less than 75 % conversion of said monomer mixture to polymer. - -DET~ILED DE~RIPTI~N
Figure 1 is a schematic drawing of a reactor system which may be ~Isec in accordance with the present invention.
The monomers of Formula I useful in accordance with the present 10 invention may be obtained from a number of sources. Preferably the monomer is obtained from the fermentation of a relatively inexpensive feed stock s~lch as starch derived from sugar(s) etc. However, it should be borne in mind that generally such procedures result in a racemic mixture of the d, and l, monomer and the polymerization of such a mixture will result in a polymer having a relatively low level of crystallinity. Preferably the monomers will be selectecl ~o to provide higher crystallinity polymers comprising a relatively grater amoullt, preferably at least 75 more preferably at least 85 weight % of the 1, monomer and up to about 25 preferably less than 15 weight % of the d monomer. Such a blend of monomers should also provide relatively higher melting polymers, having a melting temperature in the range from 130 to 170~. However, other mixtures of the monomers may be used ;f melting temperature is not a 30 significant concern as would be the case for example in blister packaging.
A particularly usefill monomer of Formula 1 may be a lactide, that is a alpha hydroxy lactic acid. Suitable monomers of Formula 1 also inclucle may be a Cl-8 alkyl ester of lactide. Switable copolymerizable monomers include cyclic C24 alkylene oxides such as polypropylene oxide. Other f~mctional :
; , - - , . . . . . . . ... . . . . . .
. . ;.: . .. ..
, , : ' ~
X~s6S4~
monomers may be included in the monomeric mixture provided they will not significantly hydrolyse the resulting polymer. Preferably, the copolymeriz~ble monomers will be esters.
The monomeric mixture may comprise 100 weight % of one or more monomers of Formula 1. Preferably, the mixture will comprise from 100 to 65 more preferably 100 to 85 weight % of one or more monomers oiF Formula I, and from 0 to 35 preferably not more than about 15 weight % of one or more copolymerizable monomers.
The present invention will now be described in association with Figure l in which like parts have like numbers.
The monomers are fed into a prereactor 1 which is a heated vessel. The 20 vessel may be heated by o;l or steam or pressurized water maintained at initi~l temperature Tl. The vessel is heated to above the melting point of the monomer mixture to be polymerized. Typically the temperature will be from about 125 to 150C. The monomers may be fed to the prereactor in dry form or may be in the form of a solution or suspension. If the monomers are in the form of a solution the concentration of monomers in solvent or diluent should 30 be as high as practicable, and preferably not less than about 85 % by weight.
There are a number of suitable diluents or solvents including C6 ,~ aromatic solvents, C6 ~2 alkanes which are unsubstituted or substituted by a Cl 4 alkyl radical, and Cl 6 alkyl ketones. Suitable aromatic diluents include ethyl benzene and toluene. Suitable C6 ,2 alkanes include hexane and ethyl hexane. Suitable . ~ ,. . . . .
. . ' .. :: ~ . : ............................... ~ :
~ ~ ";," ' ",,.., , ': ' '.
,~
X~565~g C1-6 ketones include acetone. The prereactor is joined to the first reactor by aheated line 2 maintained at constant temperature. The monomer melt is pumpecl to the first reactor 4 by pump 3. The pump is also heated to maintain a constant temperature of at least Tl. The heating means on the pump 3 and line 2, may be any suitable means such as an electric heating line steam line or lloto oil and preferably controlled independently.
In an alternate embodiment the lactide monomer may also be deliverecl directly to the first reactor using a dry bulk feed apparatus. Such as approach -is of greater simplicity as it replaces the pre-reactor, metering pumps, associated lines, heating equ;pment and controls, with a simple self-containecl unheated device. In addition such a feed device provides a simple process to 20 stop the process without compromising monomer feed which otherwise would be in a melt. However, it should be noted that such a feed device should be equipped with water cooling capability to avoid premature melting of incoming monomer. Premature melting could lead to monomer feed blockage.
~ eactor 1 and also the subsequent reactors may typically be a stirred vessel, such as a continuous stirred tank reactor, capable of operating at 30 reduced and elevated pressure and temperatures up to about 250C. The reactor configuration may be spherical, cylindrical or tubular. The agitator may be of any suitable type for the reactor including turb;ne, anchor, paddles and screw conveyor, or comb;nations thereof, such as an ax;al flow turb;ne in combination w;th peripheral anchor(s) or anchors in comb;nation with peripheral a single or : - : . . . -.
~ ~ ~ . - . .. . . .
-, . . . . . . . . . . .
."...... ,. . , . . , . : . . : : :
', ' .'''~' '', ' ' ', '. .'' ;.' .' ' . ~
2~S~5~9 double helix r;bbon.
In a preferred, optional, embodiment a catalyst is used to increase the rate of reaction. A wide range of catalysts are suitable to promote the rate of the reaction. The catalyst may be an acid cation exchange resin, acid clay, activated clay, bentonite, alumina, or an aluminurn complex of the formula lO Al(O-R)3 where R is a C~.6 alkyl radical, talc, silicic acid, metal complexes of the formula RlMR2 wherein R~ and R2 independently may be selected from the group consisting of C"~, preferably a Cs lo carboxy radicals, an oxygen atom, a halogen atom,and M is a Group II or IV metal atom. Preferably, M is selected from the group consisting of magnesium, calcium, tin and lead. Preferably, R, and R2 are the same and are Cs lo carboxyl radicals. Particularly useful 20 catalysts include stannous octoate and the aluminum complex Al (O-R)3. S~lch aluminum complexes are disclosed in H. R. Dricheldorf Macromolecules Vol.
21, No. 2 p. 286 (1988).
The catalyst may be added to the first and/or any subsequent reactor. ln the drawing a catalyst vessel is shown at 5. The catalyst may be used as a dilute solution or suspension. However, preferably the catalyst is used in 30 undilute form. The catalyst vessel is connectecl to the first reactor by a line 6 and a pump 7. As noted-above, the catalyst vessel need not be only connectecl to the first reactor. It may be connected t~ one or more subsequent reactors.
The monomers and optionally catalyst are fed to the first reactor 4. The first reactor 4 has a jacket 8 which may be heated by steam or hot oil or , . .
. . . . . .
' . , , ' ~ '' ' ' ,' .: , , . . .
:; : ' . ' , ,~ .
` ; ' " " ` : `. -' . , `:
.'` ' . ' ' 2~S65~9 pressurized hot water to a temperature T3. The reactor is operated at temperatures from about lS0 to 225, preferably from 175 to 200, most pre~erably about 175C and at a pressure from about 0.5 to 5.0, preferably about 1.0 atmospheres pressure. Typically, the reactor is a stirred tank reactor.
That is there is agitation in the reactor using typical systems as described above.
The monomers and optional catalyst are kept in the first reactor for a period of time to permit a conversion from about 35 to 85 % depending on the number of reactors in the chain. Typically the conversion of monomer to polymer coming out of the first reactor should be from about 50 to 80%. The residence time in the first reactor should be from 1 to 3 hours depend;ng on thesize of the reactor and the rate of feed to the reactor. ;~The polymer melt is pumped from the first reactor to the second reactor 9 by a pump 10 through a heated or insulated line 17 maintain at T3. The second reactor, like the first reactor also has a jacket 11 and is maintained atT4. The second reactor is operated at temperatures from lS0 to about 250, most pre~erably from about 185 to 200C.
The polymer melt is held in the second reactor for a period of time from - -about 1 to 3 hours to bring the conversion up to from about 75 to 95, most preferably from 90 to 95% .
The polymer melt is then pumped from the second reactor by a pump 12.
In the embodiment shown in the drawing the polymer melt is pumped througll line 13 to reactor (or preheated) 14. The reactor is preferably a t~lbe shell type ., . ~ . . , . ~ ,.... . ..
: ................. . " . . . . . . ... . . .
. . -. . . . , . , ... : , .. :, ..
; , :, -, , , .. . , .. . ~ ; .. . ..
. .: ., ... ~ . ., .. .: - .
, . . . ~ , .... . ... . . ..
,, ,, " , . .: .. : . . . .
~Q56Sfi9 heat exchanger. Reactor 3 rnay comprise a single pass tul~e in shell heat exchanger with static mixers for a more uniform product; or an extruder-type device if additional pressure is required. The shell enclosing the tubes thro~lgh which the polymer melt passes is heated and maintained at a temperature of T3 using suitable heating means such as electric heaters, hot oil, water or steam.
o The preheater is heated to temperatures up to about 250C. More typically the preheater will be heated to from about 180 to 210 preferably froln190 to 200, most preferably about 200C. The residence time of the polymer melt in the preheater may range from about 5 to 15 minutes. Preferably the time is kept a short as possible to minimize polymer degradation and/or depolymerization. The pressure in the preheater should range from abo~lt 0.1 to 1.5 typically about 0.5 atmospheres.
Generally, the polymer melt e~its the preheater directly into the upper end of devolatilizer 15. The devolatilizer is operated at a temperature T6 from about 150 up to about 225, preferably from about 200 to 220C. The internal pressure in the devolatilizer is below atmospheric, typically less than abo~lt 0.02, most preferably less than about 0.01 most preferably less than about 0.005 atmospheres. While the embodiment in Figure 1 shows only one devolatilizer the devolatilizer may comprise a series of two devolatilizers as are disclosed in a mlmber of patents in the name of Monsanto. The devolatilizer may be a falling strand devolatilizer. That is the polymer melt falls as strandsfrom the top to the bottom of the devolatilizer. As the polymer descends to the g ~,- , , - . . . :
:. . -, ,, . ~ . . ~ . .
. - . . . . . . . . . . .
, . . . . . .
. .
. .. , .. : , .. , . - .- ., . . , . . .:: . .
.. . .. : . . . . . :, , . - . . . . .
:, . . , , . ~ .
., ,. .. . . . , ~ . :
. . , . . , .
2QS654~
bottom of the clevolatilizer the unreacted monomer and diluent evaporate from the polymer and are withdrawn from the devolatilizer. Depending on the polyrner viscosity and the level of unreacted monomer polymer distributors may be used. For e~cample, the polymer melt could be held in a sub atmospheric chamber for longer periods of times by using a buffer or catcher tray, such as o those disclosed in U.S. Patent application 271,636 in the name of Polysar Financial Services S.A. A further alternative could be to use an extruder type devolatilizer equipped with a single or multi-stage vacuum apparatus to ach;eve ~ -vacuum levels as low as 0.002 atmospheres. Also a suitable carrier solvent such as nitrogen, toluene, ethyl benzene etc., may be used as a nucleating agent and to aid in reducing the partial pressure of unreacted lactide monomer. This would be beneficial in trying to reduce the final level of lactide monomer in the finished product.
Yet another approach could be to use thin film (wiped-film) evaporators where the combination of shorter dwell times, high ratios of surface area to volume and reduced shear rate is of benef~t to the properties of the finished product.
The volatiles from the devolatilizer pass to a condenser 16. The condenser may comprise one or more stages or zones at different temperatllres to more completely condense the volatiles and to poss;bly separate the volatiles into dif~erent fractions. The separation may also be achieved by using thin film separators and by chang;ng or increasing the amount of carrier diluent or .... . - ,. .. , ... , , , .. , , . :. .,.. ,, : ... , , . ., . .,: . .
.. . .. , ,... , , : . .:: .. , - : . :
. .. . . . . . .. . . .
.: . ." :. ,. . : . .. .. .. . .
.. . . . . . ...
; . :. ,.. .,, - , . .. , :
.. . . . . . . . .
2~S6~49 solvent.
The resulting polymer may then extruded as strands and cooled ancl chopped into pellets which then may be moulded, extruded, blown or thermoformed into various articles.
The polymer resulting from the process of the present invention sho~lld o have an intrinsic viscosity from about 0.5 to about 2.5 indicating a molec~llar weight from about 50,000 to about 300,000.
The process of the present invention has been described in association with two reactors. However, the chain could comprise from two to five, more typically two to three reactors.
The present invention will now be illustrated by the -following non-20 limiting example in which unless otherwise indicated parts are parts by weight.
Example 1 A continuous polymerization of l-lactide was carried out using a pilot plant having a single CSTR reactor in a layout as in Figure 1. Af!ter reaching steady state in about 7 hours, the monomer was melted in a p~erea,ctor and fed into the reactor at a rate of 10 lb/hr. The reactor was operated atll78C. The 30 reactor was a stirred tank reactor. A catalyst comprising stanno~ls 2-ethyl hexanoate was fed to reactor at a rate of 1-1.5 g./hr. Dlle to a mechanical problem the catalyst feed was 0.1% based on monomer. The target feed was 0.65~ based on monomer. As a result the molecular weight of the resulting laGtide polymer was low. The residence time in the first reactor was about 4 .. . , ~ . ... . . . . .
. , . ~ . " , , , ., ., : . . ., . . . . :. ~ ..
- . .. - , . . . ..
: . , .- .. ,. ~ . .. .. . . ..
.. . . .
, . . . . .. . . . . . . .
.: . . - ., ",.. ,: . . . . .
. . .
hours. The conversion in the reactor after reaching steady state was from 95.5 to 96%.
Due to the problem with catalyst feed the product exiting the reactor was sampled and conversion (gravimetric in an oven) was determined. As indicatecl the conversion was constant. The other variables including temperature, RPM
o of the stirrer, etc. remained essentially constant, with in experimental error given the continuous nature of the process. The conversion result during start-up and while running are set forth in Table 1.
.
.
. .
.. . . .
,.. .
.
2~5~i5 Contimlolls Bulk Polylactide Proc~ss ¦ DATE TIMEConversion % SOL~DS (Oven method) I~
12/12/90_ 09:50 54.1 12/12/9010:50 97.1 0 12/12/9011:50 93.6 12/12/9012:50 92.5 _ 12/12/9013:50 92.9 12/12/90 16.45 _ 96.8 12/12/90 18: 15 95.3 l _ _ I
12/12/90 21 :50 96.1 12/13/90 _ 00:50 96.8 12/13/9û 04:50 96.8 12/13/90 09:55 89.~ (*) 12/13/90 12:00 95.5 Onset of ~ontinuous Operation: 17:00 hours on 12/12 End of Continuous Operation: 13:30 hours on 12/13 TOT~L Continuous Operation: 20:50 hours ~*) sample degraded during oven test.
The results show that lactide polymer may be produced by a continuous process.
,:
- ,, , , ; , , . , , ., ~ ., . ~ ,: , :
:' ' - " ' ' . ' , : - ' ~ , . . ''. ::' '~
-: : , . . . . . . .
.
Claims (13)
1. The present invention provides a continuous process for the polymerization of monomeric mixture comprising from 100 to 60 weight % of one or more monomers the formula wherein R1 is a hydrogen atom or a C1-4 alkyl radical; and R2 is a hydrogen atom or a C1-8 alkyl radical, provided that R1 and R2 cannot both be a hydrogen atom; and 0 - 40 weight % of one or more copolymerizable monomers which comprises:
(a) forming a melt or solution of said monomers;
(b) passing said monomeric melt or solution continuously through at least one reactor(s) operated at temperatures from 150 to 250°C and at a pressure ranging from 0.5 to 5 atmospheres at a rate and for a residence time to provide not less than 75% conversion of said monomer mixture to polymer.
(a) forming a melt or solution of said monomers;
(b) passing said monomeric melt or solution continuously through at least one reactor(s) operated at temperatures from 150 to 250°C and at a pressure ranging from 0.5 to 5 atmospheres at a rate and for a residence time to provide not less than 75% conversion of said monomer mixture to polymer.
2. The process according to claim 1, wherein said copolymerizable monomer is selected from the group consisting of C2-4 alkylene oxides.
3. The process according to claim 1, further comprising passing said melt of polymer through a preheater operated at a temperature from 180 to 220°C at a pressure from 0.1 to 1.5 atmospheres for a time from 0.5 to 5 minutes.
4. The process according to claim 3, further comprising substantially upon exit from said preheater passing said polymer melt through a devolatilizer operated at a temperature from 150 to 225°C and at a pressure of less than 0.02 atmospheres.
5. The process according to claim 1 wherein each successive reactor is operated at a temperature of up to 15°C higher than the preceding reactor.
6. The process according to claim 4, wherein each successive reactor is operated at a temperature from 5 to 10°C higher than the preceding reactor.
7. The process according to claim 5, wherein said reactors are continuous stirred tank reactors.
8. The process according to claim 6, wherein said devolatilizer is a falling strand devolatilizer.
9. The process according to claim 6, wherein the volatiles recovered from said falling strand devolatilizer is recycled to said reactors.
10. The process according to claim 8, further comprising adding to one or more said reactor(s) a catalyst.
11. The process according to claim 9, wherein said catalyst is selected from the group consisting of tin esters of C1-8 carboxylic acids.
12. The process according to claim 10, wherein the diluent or solvent for said catalyst is selected from the group consisting of C6-12 aromatic solvents, C6-12 alkanes which are unsubstituted or substituted by a C1-4 alkyl radical which are unsubstituted or substituted by a C1-4 alkyl radical, C1-6 ketones.
13. The process according to claim 11, wherein said catalyst is stannous octoate.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US659,567 | 1991-02-22 | ||
| US07/659,567 US5136017A (en) | 1991-02-22 | 1991-02-22 | Continuous lactide polymerization |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2056549A1 true CA2056549A1 (en) | 1992-08-23 |
Family
ID=24645884
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002056549A Abandoned CA2056549A1 (en) | 1991-02-22 | 1991-11-28 | Continuous lactide polymerization |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US5136017A (en) |
| EP (1) | EP0499747A3 (en) |
| JP (1) | JPH0593050A (en) |
| CA (1) | CA2056549A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010147088A1 (en) | 2009-06-19 | 2010-12-23 | 東洋エンジニアリング株式会社 | Process for production of polylactic acid |
Families Citing this family (42)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6323307B1 (en) | 1988-08-08 | 2001-11-27 | Cargill Dow Polymers, Llc | Degradation control of environmentally degradable disposable materials |
| US5247059A (en) * | 1992-01-24 | 1993-09-21 | Cargill, Incorporated | Continuous process for the manufacture of a purified lactide from esters of lactic acid |
| US6005067A (en) * | 1992-01-24 | 1999-12-21 | Cargill Incorporated | Continuous process for manufacture of lactide polymers with controlled optical purity |
| US6326458B1 (en) | 1992-01-24 | 2001-12-04 | Cargill, Inc. | Continuous process for the manufacture of lactide and lactide polymers |
| US5247058A (en) * | 1992-01-24 | 1993-09-21 | Cargill, Incorporated | Continuous process for manufacture of lactide polymers with controlled optical purity |
| US5258488A (en) * | 1992-01-24 | 1993-11-02 | Cargill, Incorporated | Continuous process for manufacture of lactide polymers with controlled optical purity |
| US5142023A (en) * | 1992-01-24 | 1992-08-25 | Cargill, Incorporated | Continuous process for manufacture of lactide polymers with controlled optical purity |
| US6005068A (en) | 1992-10-02 | 1999-12-21 | Cargill Incorporated | Melt-stable amorphous lactide polymer film and process for manufacture thereof |
| US5338822A (en) * | 1992-10-02 | 1994-08-16 | Cargill, Incorporated | Melt-stable lactide polymer composition and process for manufacture thereof |
| AU5296393A (en) * | 1992-10-02 | 1994-04-26 | Cargill Incorporated | Paper having a melt-stable lactide polymer coating and process for manufacture thereof |
| WO1994008078A1 (en) * | 1992-10-02 | 1994-04-14 | Cargill, Incorporated | A melt-stable lactide polymer fabric and process for manufacture thereof |
| US5420235A (en) * | 1993-01-21 | 1995-05-30 | E. I. Du Pont De Nemours And Company | Continuous poly (hydroxy acid) polymerization using a counter-current impeller mixing system |
| DE4340400A1 (en) * | 1993-11-26 | 1995-06-01 | Wacker Chemie Gmbh | Aqueous dispersions of organopolysiloxanes |
| DE69428583T2 (en) * | 1993-12-28 | 2002-06-27 | Dainippon Ink & Chemicals | Process for the continuous production of lactide copolymer |
| US5883222A (en) * | 1995-10-04 | 1999-03-16 | Kyowa Hakko Kogyo Co., Ltd. | Process for producing polyhydroxycarboxlic acid |
| US5844067A (en) * | 1996-04-18 | 1998-12-01 | Erneta; Modesto | Process for producing absorbable segmented copolymers with a substantially uniform sequence distribution |
| FI103581B (en) * | 1996-11-11 | 1999-07-30 | Fortum Heat And Gas Oy | A method of preparing polyhydroxy acids |
| CA2274676A1 (en) | 1996-12-31 | 1998-07-09 | James Hongxue Wang | Water-responsive polymer compositions and method of making the same |
| FI107337B (en) | 1997-02-14 | 2001-07-13 | Fortum Oil & Gas Oy | A method for polymerizing lactide |
| EP0961800B1 (en) * | 1997-02-14 | 2002-12-11 | Fortum Oil and Gas Oy | Method for the removal and recovery of lactide from polylactide |
| US6552162B1 (en) | 1997-07-31 | 2003-04-22 | Kimberly-Clark Worldwide, Inc. | Water-responsive, biodegradable compositions and films and articles comprising a blend of polylactide and polyvinyl alcohol and methods for making the same |
| US5945480A (en) * | 1997-07-31 | 1999-08-31 | Kimberly-Clark Worldwide, Inc. | Water-responsive, biodegradable fibers comprising polylactide modified polylactide and polyvinyl alcohol, and method for making the fibers |
| US6075118A (en) * | 1997-07-31 | 2000-06-13 | Kimberly-Clark Worldwide, Inc. | Water-responsive, biodegradable film compositions comprising polylactide and polyvinyl alcohol, and a method for making the films |
| US5952433A (en) * | 1997-07-31 | 1999-09-14 | Kimberly-Clark Worldwide, Inc. | Modified polyactide compositions and a reactive-extrusion process to make the same |
| US6350518B1 (en) | 1998-06-01 | 2002-02-26 | Kimberly-Clark Worldwide, Inc. | Methods of making blend compositions of an unmodified poly vinyl alcohol and a thermoplastic elastomer |
| US6562931B1 (en) | 1999-10-29 | 2003-05-13 | Alliedsignal Inc. | Room temperature vulcanizable silicone compositions with improved adhesion to acrylic |
| US6960626B2 (en) * | 2000-01-21 | 2005-11-01 | Cyclics Corporation | Intimate physical mixtures containing macrocyclic polyester oligomer and filler |
| US7750109B2 (en) | 2000-09-01 | 2010-07-06 | Cyclics Corporation | Use of a residual oligomer recyclate in the production of macrocyclic polyester oligomer |
| US7767781B2 (en) | 2000-09-01 | 2010-08-03 | Cyclics Corporation | Preparation of low-acid polyalkylene terephthalate and preparation of macrocyclic polyester oligomer therefrom |
| US20020111458A1 (en) * | 2000-12-01 | 2002-08-15 | Masato Minami | Method for producing aliphatic polyester |
| US6559275B2 (en) | 2000-12-01 | 2003-05-06 | Canon Kabushiki Kaisha | Method for producing aliphatic polyester |
| JP4487598B2 (en) | 2004-03-04 | 2010-06-23 | 株式会社日立プラントテクノロジー | Polymerization method and polymerization apparatus |
| US20090171065A1 (en) * | 2006-02-16 | 2009-07-02 | Toray Industries, Inc. A Corporation Of Japan | Polyether-polylactic acid composition and polylactic acid film containing same |
| JP2008007740A (en) | 2006-06-01 | 2008-01-17 | Daicel Chem Ind Ltd | Method for producing polyester block copolymer |
| EP2452701A4 (en) | 2009-08-27 | 2014-04-23 | Terumo Corp | Medical device for delivery of drug |
| KR101548314B1 (en) * | 2012-12-17 | 2015-08-28 | 주식회사 엘지화학 | Preparation Method of Polylactide Resin |
| ES2649369T3 (en) | 2012-12-18 | 2018-01-11 | Uhde Inventa-Fischer Gmbh | Device and method for separating a cyclic diester from polymeric melts |
| KR101692988B1 (en) | 2014-11-27 | 2017-01-04 | 롯데케미칼 주식회사 | Polylactide resin having improved thermal stability |
| DE102015206688B4 (en) | 2015-04-14 | 2016-11-24 | Thyssenkrupp Ag | A process for the crystallization and separation of low molecular weight components from a granulate of a crystallizable thermoplastic material and device therefor |
| EP3303445B1 (en) | 2015-06-05 | 2020-12-16 | Council of Scientific and Industrial Research | A one step process for the pelletisation of poly lactic acid without melt processing |
| EP3318590B1 (en) | 2016-11-08 | 2020-08-05 | thyssenkrupp AG | Method for the separation of volatile compounds from viscous products having a thin film evaporator |
| RU2637923C1 (en) * | 2016-11-30 | 2017-12-08 | Общество с ограниченной ответственностью "Медин-Н" | Method of producing (co) polymer of glycolide and/or lactide for production of absorbable surgical products |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1425333A (en) * | 1963-11-08 | 1966-01-24 | Du Pont | Preparation of high molecular weight polylactides |
| US3879352A (en) * | 1973-02-06 | 1975-04-22 | Eastman Kodak Co | Continuous process for polymerizing {60 ,{60 -disubstituted-{62 -propiolactones |
| US4643734A (en) * | 1983-05-05 | 1987-02-17 | Hexcel Corporation | Lactide/caprolactone polymer, method of making the same, composites thereof, and prostheses produced therefrom |
| EP0372221B1 (en) * | 1988-11-01 | 2000-01-19 | Boehringer Ingelheim Pharma KG | Continuous process for the preparation of resorbable polyesters, and their use |
-
1991
- 1991-02-22 US US07/659,567 patent/US5136017A/en not_active Expired - Fee Related
- 1991-11-28 CA CA002056549A patent/CA2056549A1/en not_active Abandoned
- 1991-12-20 EP EP19910311854 patent/EP0499747A3/en not_active Ceased
-
1992
- 1992-01-29 JP JP4014011A patent/JPH0593050A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2010147088A1 (en) | 2009-06-19 | 2010-12-23 | 東洋エンジニアリング株式会社 | Process for production of polylactic acid |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0499747A3 (en) | 1993-01-13 |
| US5136017A (en) | 1992-08-04 |
| JPH0593050A (en) | 1993-04-16 |
| EP0499747A2 (en) | 1992-08-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2056549A1 (en) | Continuous lactide polymerization | |
| RU2510990C2 (en) | Method of continuous obtaining of polyesters | |
| US7132484B2 (en) | Continuous process for producing poly (trimethylene terephthalate) | |
| US3185669A (en) | Total liquid phase esterification | |
| RU2005106178A (en) | COMPLEX POLYESTER POLYMER WITH HIGH CHARACTERISTIC VISCOSITY OF MELT PHASE CATALYZED WITH ANTIMONY CONTAINING COMPOUNDS | |
| WO2001042334A1 (en) | Method of preparing modified polyester bottle resins | |
| US6127493A (en) | Pressure polymerization of polyester | |
| US5331066A (en) | Process for producing polyester ether copolymer | |
| US3271370A (en) | Poly(l,x-cyclohexylenedimethylene ter- ephthalate) process using substantial- ly equal proportions of reactants | |
| US6111064A (en) | Pressure polymerization of polyester | |
| US6403762B1 (en) | Solid state polymerization process for poly(trimethylene terephthalate) utilizing a combined crystallization/preheating step | |
| US4319017A (en) | Semi or fully continuous process for polyester of bisphenol and dicarboxylic acid by transesterification polymerization and product thereof | |
| KR20000071024A (en) | Process for the polymerization of lactide | |
| GB1578151A (en) | Apparatus and process for producing poly-condensates | |
| EP1491569A1 (en) | Polytrimethylene terephthalate resin | |
| GB2361925A (en) | High temperature solid state polymerisation of poly(trimethylene terephthalate) | |
| JPH09124778A (en) | Production of polylactic acid | |
| CN109796584B (en) | Preparation system and preparation method of aromatic thermotropic liquid crystal polymer | |
| JP3517857B2 (en) | Polylactic acid production method | |
| US4465819A (en) | Semi or fully continuous process for polyester of bisphenol and dicarboxylic acid by transesterification polymerization and product thereof | |
| US4415721A (en) | Semi or fully continuous process for polyester of bisphenol and dicarboxylic acid by transesterification polymerization and product thereof | |
| JP3517856B2 (en) | Polylactic acid production method | |
| NO116300B (en) | ||
| CN113773480B (en) | Catalyst composition for preparing polyglycolide and preparation method of polyglycolide | |
| JP3517858B2 (en) | Polylactic acid production method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued | ||
| FZDE | Discontinued |
Effective date: 20011128 |