US5338822A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Melt-stable lactide polymer composition and process for manufacture thereof
Assignee: Cargill Inc
•
Filing: 1992-10-02
•
Granted: 1994-08-16
•
Expires: 2012-10-02
Abstract
Abstract A lactide polymer composition combining compositional and purity limitations and catalyst optimization or addition of stabilizing agents resulting in a melt-stable polymer is disclosed. The melt-stable lactide polymer comprises a plurality of polylactide polymer chains, residual lactide in concentration of less than 2 percent and water in concentration of less than 1000 parts-per-million. A stabilizing agent in an amount sufficient to reduce depolymerization of the lactide polymer during melt-processing or alternatively, control of catalyst level at a molar ratio of monomer to catalyst greater than 3000:1 is also included in the melt-stable composition. A process for manufacture of a melt-stable lactide polymer composition includes polymerizing a lactide mixture and adding stabilizing agents sufficient to reduce depolymerization of the polylactide during melt-processing, followed by devolatilizing the polylactide to remove monomer and water.
Inventors
- 👤 Patrick R. Gruber
- 👤 Jeffrey J. Kolstad
- 👤 Eric S. Hall
- 👤 Robin S. Eichen Conn
- 👤 Christopher M. Ryan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:38
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; A; A61; A61L; A61L15/00; A61L15/16; A61L15/22; A61L15/26; A61L31/00; A61L31/04; A61L31/06; C08G; C08G63/00; C08G63/02; C08G63/06; C08G63/08; C08G63/88; C08G63/90; C08L; C08L67/00; C08L67/04; C09; C09D; C09D167/00; C09D167/04; D; D01; D01F; D01F6/00; D01F6/58; D01F6/62; D01F6/625; D04; D04H; D04H1/00; D04H1/40; D04H1/42; D21; D21H; D21H19/00; D21H19/10; D21H19/14; D21H19/24; D21H19/28; D21H19/36; D21H19/44; D21H19/62; C08G2230/00; C08J2367/00; C08J2367/04; C08L101/00; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31786; Y10T428/3179; Y10T428/31801; Y10T428/31804; Y10T428/31808; Y10T428/31815; Y10T428/31819; Y10T428/31971; Y10T428/31993
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
112 words
A melt-stable lactide polymer composition, comprising: (a) a plurality of polylactide polymer chains, said plurality having a number average molecular weight of from about 10,000 to about 300,000; (b) lactide in a concentration of less than about 2 percent by weight; (c) water, if present at all, present in a concentration of less than about 1000 parts-per-million; and (d) a stabilizing agent in an amount sufficient to reduce depolymerization of said plurality of polylactide polymer chains during melt-processing, such that the generation of lactide is less than about 2 percent by weight of the composition from a devolatilized sample in the first hour at a temperature of 180° C. and atmospheric pressure.
Claim 2
Dependent Claim
112 words
A melt-stable lactide polymer composition, comprising: (a) a plurality of polylactide polymer chains, said plurality having a number average molecular weight of from about 10,000 to about 300,000; (b) lactide in a concentration of less than about 2 percent by weight; (c) water, if present at all, present in a concentration of less than about 1000 parts-per-million; and (d) a stabilizing agent in an amount sufficient to reduce depolymerization of said plurality of polylactide polymer chains during melt-processing, such that the generation of lactide is less than about 2 percent by weight of the composition from a devolatilized sample in the first hour at a temperature of 180° C. and atmospheric pressure.
Claim 3
Dependent Claim
46 words
The melt-stable lactide polymer composition of claim 1, wherein the plurality of polylactide polymer chains are the reaction product of polymerizing a lactide mixture comprising about 5 percent by weight to about 50 percent by weight meso-lactide and about 95 percent by weight or less L-lactide.
Claim 4
Dependent Claim
27 words
The melt-stable lactide polymer composition of claim 1, wherein the plurality of polylactide polymer chains have a number average molecular weight from about 15,000 to about 150,000.
Claim 5
Dependent Claim
20 words
The melt-stable lactide polymer composition of claim 1, wherein the lactide concentration is less than about 0.5 percent by weight.
Claim 6
Dependent Claim
15 words
The melt-stable lactide polymer composition of claim 1, wherein the stabilizing agent is an antioxidant.
Claim 7
Dependent Claim
19 words
The melt-stable lactide polymer composition of claim 1, wherein the stabilizing agent comprises an antioxidant and a water scavenger.
Claim 8
Dependent Claim
15 words
The melt-stable lactide polymer composition of claim 5, wherein the antioxidant is a phosphite-containing compound.
Claim 9
Dependent Claim
18 words
The melt-stable lactide polymer composition of claim 5, wherein the antioxidant is a hindered phenolic or phenolic compound.
Claim 10
Dependent Claim
57 words
The melt-stable lactide polymer composition of claim 5, wherein the antioxidant is selected from the group consisting of: trialkyl phosphites, mixed alkyl/aryl phosphites, alkylated aryl phosphites, sterically hindered aryl phosphites, aliphatic spirocyclic phosphites, sterically hindered phenyl spirocyclics, sterically hindered bisphosphonites, hydroxyphenyl propionates, hydroxy benzyls, alkylidene bisphenols, alkyl phenols, aromatic amines, thioethers, hindered amines, hydroquinones and mixtures thereof.
Claim 11
Dependent Claim
29 words
The melt-stable lactide polymer composition of claim 6, wherein the water scavenger is elected from the group consisting of carbodiimides, anhydrides, acyl chlorides, isocyanates, alkoxy silanes and mixtures thereof.
Claim 12
Dependent Claim
36 words
The melt-stable lactide polymer composition of claim 6, wherein the water scavenger is a desiccant selected from the group consisting of: clay, alumina, silica gel, zeolites, calcium chloride, calcium carbonate, sodium sulfate, bicarbonates and mixtures thereof.
Claim 13
Dependent Claim
59 words
The melt-stable lactide polymer composition of claim 1, wherein the composition further comprises: (e) catalyst means for catalyzing the polymerization of lactide to form the polylactide polymer chains, said catalyst means incorporated into the melt-stable lactide polymer composition during polymerization; and (f) a catalyst deactivating agent in an amount sufficient to reduce catalytic depolymerization of said polylactide polymer chains.
Claim 14
Dependent Claim
29 words
The melt-stable lactide polymer composition of claim 2 wherein the plurality of polylactide polymer chains is the reaction product of polymerization at a temperature greater than about 160° C.
Claim 15
Dependent Claim
131 words
An amorphous melt-stable lactide polymer composition, comprising: (a) a plurality of polylactide polymer chains, said plurality of polylactide polymer chains resulting from the polymerization of a lactide mixture comprising about 5 to about 50 percent by weight meso-lactide and about 95 percent by weight or less L-lactide; (b) lactide in a concentration of less than about 2 percent by weight; (c) water, if present at all, present in a concentration of less than about 1000 parts-per-million; and (d) a stabilizing agent in an amount sufficient to reduce depolymerization of said plurality of polylactide polymer chains during melt-processing, such that the generation of lactide is less than about 2 percent by weight of the composition from a devolatilized sample in the first hour at a temperature of 180° C. and atmospheric pressure.
Claim 16
Dependent Claim
131 words
An amorphous melt-stable lactide polymer composition, comprising: (a) a plurality of polylactide polymer chains, said plurality of polylactide polymer chains resulting from the polymerization of a lactide mixture comprising about 5 to about 50 percent by weight meso-lactide and about 95 percent by weight or less L-lactide; (b) lactide in a concentration of less than about 2 percent by weight; (c) water, if present at all, present in a concentration of less than about 1000 parts-per-million; and (d) a stabilizing agent in an amount sufficient to reduce depolymerization of said plurality of polylactide polymer chains during melt-processing, such that the generation of lactide is less than about 2 percent by weight of the composition from a devolatilized sample in the first hour at a temperature of 180° C. and atmospheric pressure.
Claim 17
Dependent Claim
28 words
The amorphous melt-stable lactide polymer composition of claim 14, wherein the plurality of polylactide polymer chains have a number average molecular weight from about 15,000 to about 150,000.
Claim 18
Dependent Claim
15 words
The amorphous melt-stable lactide-polymer composition of claim 14, wherein the stabilizing agent is an antioxidant.
Claim 19
Dependent Claim
20 words
The amorphous melt-stable lactide polymer composition of claim 14, wherein the stabilizing agent comprises an antioxidant and a water scavenger.
Claim 20
Dependent Claim
16 words
The amorphous melt-stable lactide polymer composition of claim 16, wherein the antioxidant is a phosphite-containing compound.
Claim 21
Dependent Claim
19 words
The amorphous melt-stable lactide polymer composition of claim 16, wherein the antioxidant is a hindered phenolic or phenolic compound.
Claim 22
Dependent Claim
58 words
The amorphous melt-stable lactide polymer composition of claim 16, wherein the antioxidant is selected from the group consisting of: trialkyl phosphites, mixed alkyl/aryl phosphites, alkylated aryl phosphites, sterically hindered aryl phosphites, aliphatic spirocyclic phosphites, sterically hindered phenyl spirocyclics, sterically hindered bisphosphonites, hydroxyphenyl propionates, hydroxy benzyls, alkylidene bisphenols, alkyl phenols, aromatic amines, thioethers, hindered amines, hydroquinones and mixtures thereof.
Claim 23
Dependent Claim
30 words
The amorphous melt-stable lactide polymer composition of claim 17, wherein the water scavenger is selected from the group consisting of carbodiimides, anhydrides, acyl chlorides, isocyanates, alkoxy silanes and mixtures thereof.
Claim 24
Dependent Claim
36 words
The amorphous melt-stable lactide polymer composition of claim 17, wherein the water scavenger is a desiccant Selected from the group consisting clay, alumina, silica gel, zeolites, calcium chloride, calcium carbonate, sodium sulfate, bicarbonates and mixtures thereof.
Claim 25
Dependent Claim
60 words
The amorphous melt-stable lactide polymer composition of claim 14, wherein the composition further comprises: (e) catalyst means for catalyzing the polymerization of lactide to form the polylactide polymer chains, said catalyst means incorporated into the melt-stable lactide polymer composition during polymerization; and (f) a catalyst deactivating agent in an amount sufficient to reduce catalytic depolymerization of said polylactide polymer chains.
Claim 26
Dependent Claim
78 words
A melt-stable lactide polymer composition comprising: (a) a plurality of polylactide polymer chains, said plurality of polylactide polymer chains having a number average molecular weight of from about 10,000 to about 300,000; (b) lactide in a concentration of less than about 2 percent by weight; (c) water, if present at all, present in a concentration of less than about 1,000 parts-per-million; and (d) residual catalyst in a molar ratio of monomer to catalyst of greater than about 3000:1.
Claim 27
Dependent Claim
78 words
A melt-stable lactide polymer composition comprising: (a) a plurality of polylactide polymer chains, said plurality of polylactide polymer chains having a number average molecular weight of from about 10,000 to about 300,000; (b) lactide in a concentration of less than about 2 percent by weight; (c) water, if present at all, present in a concentration of less than about 1,000 parts-per-million; and (d) residual catalyst in a molar ratio of monomer to catalyst of greater than about 3000:1.
Claim 28
Dependent Claim
46 words
The melt-stable lactide polymer composition of claim 24, wherein the plurality of polylactide polymer chains are the reaction product of polymerizing a lactide mixture comprising about 5 percent by weight to about 50 percent by weight meso-lactide and about 95 percent by weight or less L-lactide.
Claim 29
Dependent Claim
27 words
The melt-stable lactide polymer composition of claim 24, wherein the plurality of polylactide polymer chains have a number average molecular weight from about 15,000 to about 150,000.
Claim 30
Dependent Claim
20 words
The melt-stable lactide polymer composition of claim 24, wherein the lactide concentration is less than about 0.5 percent by weight.
Claim 31
Dependent Claim
133 words
A process for the manufacture of a melt-stable lactide polymer composition, comprising the steps of: (a) providing a lactide mixture, wherein said mixture contains about 5 percent by weight to about 50 percent by weight meso-lactide and about 95 percent by weight or less L-lactide; (b) polymerizing said lactide mixture to form polylactide and unreacted monomer in the presence of catalyst means for catalyzing the polymerization of lactide to form polylactide; (c) adding a stabilizing agent in an amount sufficient to reduce depolymerization of polylactide during melt-processing such that the generation of lactide is less than about 2 percent by weight of the composition from a devolatilized sample in the first hour at a temperature of 180° C. and atmospheric pressure; and (d) devolatilizing the polylactide to remove unreacted monomer and residual water.
Claim 32
Dependent Claim
133 words
A process for the manufacture of a melt-stable lactide polymer composition, comprising the steps of: (a) providing a lactide mixture, wherein said mixture contains about 5 percent by weight to about 50 percent by weight meso-lactide and about 95 percent by weight or less L-lactide; (b) polymerizing said lactide mixture to form polylactide and unreacted monomer in the presence of catalyst means for catalyzing the polymerization of lactide to form polylactide; (c) adding a stabilizing agent in an amount sufficient to reduce depolymerization of polylactide during melt-processing such that the generation of lactide is less than about 2 percent by weight of the composition from a devolatilized sample in the first hour at a temperature of 180° C. and atmospheric pressure; and (d) devolatilizing the polylactide to remove unreacted monomer and residual water.
Claim 33
Dependent Claim
13 words
The process of claim 28, wherein said catalyst means is a soluble catalyst.
Claim 34
Dependent Claim
21 words
The process of claim 29, further comprising the step of adding a catalyst deactivating agent subsequent to polymerizing said lactide mixture,
Claim 35
Dependent Claim
15 words
The process of claim 28, wherein said catalyst means is an insoluble solid supported catalyst.
Claim 36
Dependent Claim
20 words
The process of claim 28, wherein the polymerizing of step (b) occurs at a temperature greater than about 160° C.
Claim 37
Dependent Claim
23 words
The process of claim 28, further comprising the step of adding a molecular weight control agent prior to the polymerizing of step (b).
Claim 38
Dependent Claim
36 words
The process of claim 33, wherein the molecular weight control agent is added in an amount sufficient that the polylactide formed in step(b) has a number average molecular weight of between about 10,000 and about 200,000.
Claim 39
Dependent Claim
42 words
The process of claim 28, wherein the step of devolatilizing includes reducing the concentration of unreacted lactide to less than about 2 percent by weight of the polylactide and the concentration of water to less than about 1000 parts-per-million of the polylactide.
Claim 40
Dependent Claim
26 words
The process of claim 28, wherein the step of adding a stabilizing agent occurs prior to or simultaneously with the step of polymerizing said lactide mixture.
Claim 41
Dependent Claim
23 words
The process of claim 28, wherein the step of adding a stabilizing agent occurs subsequent to the step of polymerizing said lactide mixture.
References Cited (Backward Citations)
CA863673A
Cited
CA808731A
Cited
DE267826C
Cited
US1095205A
Cited
US1849107A
Cited
US1995970A
Cited
US2396994A
Cited
US2703316A
Cited
US2758987A
Cited
US2951828A
Cited
DE1083275B
Cited
US3322791A
Cited
GB1040168A
Cited
US3268487A
Cited
US3531561A
Cited
DE1543958A1
Cited
GB1108720A
Cited
US3772420A
Cited
US3887699A
Cited
US3773919A
Cited
CA923245A
Cited
US3636956A
Cited
GB1351409A
Cited
US3839297A
Cited
US3912692A
Cited
US4045418A
Cited
US4279249A
Cited
US4249531A
Cited
US4273920A
Cited
US4343931A
Cited
US4529792A
Cited
EP0052510A2
Cited
US4441496A
Cited
EP0107591A2
Cited
US4643734A
Cited
GB2145422A
Cited
US4677191A
Cited
US4683288A
Cited
US4595713A
Cited
US4728721A
Cited
US4727163A
Cited
US4789726A
Cited
DE3632103A1
Cited
US4990222A
Cited
US4960866A
Cited
US4797468A
Cited
US4766182A
Cited
US4719246A
Cited
US4800219A
Cited
US4981696A
Cited
US4835293A
Cited
US5053522A
Cited
US4983745A
Cited
EP0299730A2
Cited
EP0314245A1
Cited
US5053485A
Cited
US4950258A
Cited
US4902515A
Cited
WO1990001521A1
Cited
US5180765A
Cited
US5108399A
Cited
US5041529A
Cited
US5149833A
Cited
US5011946A
Cited
WO1991002015A1
Cited
WO1991006601A1
Cited
US5043458A
Cited
WO1991017155A1
Cited
US5023349A
Cited
US5097005A
Cited
US5023350A
Cited
WO1992000292A1
Cited
WO1992000974A1
Cited
US5136057A
Cited
US5076983A
Cited
US5134171A
Cited
WO1992004413A1
Cited
WO1992004412A1
Cited
WO1992004410A1
Cited
WO1992005168A1
Cited
WO1992005167A1
Cited
WO1992005311A1
Cited
EP0481732A1
Cited
US5210296A
Cited
US5136017A
Cited
WO1992015340A1
Cited
JPH04283227A
Cited
EP0507554A1
Cited
US5132397A
Cited
EP0510998A2
Cited
EP0515203A2
Cited
EP0532154A2
Cited
EP0533314A2
Cited
US5229528A
Cited
US5142023A
Cited
US5236560A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-08-15 | 1998-02-14 | 1998-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-08-15 | 2002-02-14 | 2002-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-08-15 | 2006-02-14 | 2006-08-16 | $7700.00 | Window Closed / Lapsed |