US4876326A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Solid state polymerization of polyester prepolymers
Assignee: Shell USA Inc
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Filing: 1988-03-11
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Granted: 1989-10-24
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Expires: 2008-03-11
Abstract
Abstract High molecular weight polyester resins such as polyethylene terephthalate, are sometimes produced from low molecular weight polyester prepolymers having the same composition by solid state polymerization. The low molecular weight polyester prepolymers which are used in such solid state polymerizations are normally prepared by conventional melt polymerizations and are generally in the form of pellets or chips. It has been unexpectedly found that solid state polymerization rates can be greatly improved by utilizing polyester prepolymers which are in the form of porous pills. By utilizing polyester prepolymers that are in the form of porous pills, higher molecular weights can be achieved after shorter solid state polymerization times.
Inventors
- 👤 Verne R. Rinehart
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 09:59
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/02; C08G63/12; C08G63/40; C08G63/78; C08G63/80
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
93 words
In a process for solid state polymerizing a polyester prepolymer into a high molecular weight polyester resin at an elevated temperature, the improvement which comprises utilizing a polyester prepolymer which is in the form of porous pills, wherein the porous pills were made by compacting a powder or the polyester prepolymer having a particle size of less than about 841 microns; wherein the elevated temperature is within the range of about 50? C. below the sticking temperature of the polyester prepolymer up to but not including the sticking temperature of the polyester prepolymer.
Claim 2
Dependent Claim
93 words
In a process for solid state polymerizing a polyester prepolymer into a high molecular weight polyester resin at an elevated temperature, the improvement which comprises utilizing a polyester prepolymer which is in the form of porous pills, wherein the porous pills were made by compacting a powder or the polyester prepolymer having a particle size of less than about 841 microns; wherein the elevated temperature is within the range of about 50? C. below the sticking temperature of the polyester prepolymer up to but not including the sticking temperature of the polyester prepolymer.
Claim 3
Dependent Claim
73 words
An improved process for solid state polymerizing a polyester prepolymer into a high molecular weight polyester resin comprising heating the polyester prepolymer to a temperature of from about 1? C. to about 50? C. below its sticking temperature, wherein the polyester prepolymer is in the form of porous pills, wherein said porous pills were made by agglomerating a powder of the polyester prepolymer having a particle size of less than about 841 microns.
Claim 4
Dependent Claim
73 words
An improved process for solid state polymerizing a polyester prepolymer into a high molecular weight polyester resin comprising heating the polyester prepolymer to a temperature of from about 1? C. to about 50? C. below its sticking temperature, wherein the polyester prepolymer is in the form of porous pills, wherein said porous pills were made by agglomerating a powder of the polyester prepolymer having a particle size of less than about 841 microns.
Claim 5
Dependent Claim
137 words
A porous pill which can be solid state polymerized at a very rapid rate into a high molecular weight polyester resin wherein said porous pill is comprised of a polyester prepolymer having an intrinsic viscosity of at least about 0.1 dl/g in a 60:40 phenol:tetrachloroethane solvent system at a temperature of 30? C. and at a concentration of 0.4 g/dl; wherein said porous pill contains a substantial volume of interstice which penetrates the porous pill and open to the outside; wherein the porous pill has a density which is within the range of about 70% to about 99% of the density of solid polyester pellets which are comprised of the same polyester prepolymer; and wherein the porous pill is made by compacting a power of the polyester having a particle size of less than about 841 microns.
Claim 6
Dependent Claim
137 words
A porous pill which can be solid state polymerized at a very rapid rate into a high molecular weight polyester resin wherein said porous pill is comprised of a polyester prepolymer having an intrinsic viscosity of at least about 0.1 dl/g in a 60:40 phenol:tetrachloroethane solvent system at a temperature of 30? C. and at a concentration of 0.4 g/dl; wherein said porous pill contains a substantial volume of interstice which penetrates the porous pill and open to the outside; wherein the porous pill has a density which is within the range of about 70% to about 99% of the density of solid polyester pellets which are comprised of the same polyester prepolymer; and wherein the porous pill is made by compacting a power of the polyester having a particle size of less than about 841 microns.
Claim 7
Dependent Claim
18 words
A porous pill as specified in claim 3 wherein said compacting is done by utilizing a compaction/granulation system.
Claim 8
Dependent Claim
17 words
A porous pill as specified in claim 3 wherein said compacting is done by utilizing extrusion equipment.
Claim 9
Dependent Claim
21 words
A porous pill as specified in claim 3 wherein said porous pill is made by compaction in a pellet mill system.
Claim 10
Dependent Claim
17 words
A process as specified in claim 1 wherein the porous pill is made utilizing a compaction/granulation system.
Claim 11
Dependent Claim
17 words
A process as specified in claim 1 wherein the porous pill is made utilizing a pellet mill.
Claim 12
Dependent Claim
21 words
A porous pill as specified in claim 3, wherein said powder has a particle size of less than about 420 microns.
Claim 13
Dependent Claim
21 words
A porous pill as specified in claim 3, wherein said powder has a particle size of less than about 250 microns.
Claim 14
Dependent Claim
15 words
A porous pill as specified in claim 3, wherein said polyester prepolymer is polyethylene terephthalate.
Claim 15
Dependent Claim
23 words
A porous pill as specified in claim 3, wherein said polyethylene terephthalate has an intrinsic viscosity of about 0.18 to about 0.29 dl/g.
Claim 16
Dependent Claim
23 words
A porous pill as specified in claim 3, wherein said polyethylene terephthalate has an intrinsic viscosity of about 0.2 to about 0.28 dl/g.
Claim 17
Dependent Claim
14 words
A process as specified in claim 1 wherein the polyester prepolymer is polyethylene terephthalate.
Claim 18
Dependent Claim
23 words
A process as specified in claim 4 wherein said elevated temperature is within the range of about 210° C. to about 255° C.
Claim 19
Dependent Claim
23 words
A process as specified in claim 14 wherein said elevated temperature is within the range of about 230° C. to about 250° C.
Claim 20
Dependent Claim
46 words
A process as specified in claim 7 wherein the polyester prepolymer is polyethylene terephthalate; wherein the elevated temperature is within the range of about 210° C. to about 255° C.; and wherein said polymerization is carried out in the presence of at least one inert gas.
Claim 21
Dependent Claim
45 words
A process as specified in claim 1 wherein said solid state polymerization is conducted in a static bed reactor wherein the porous pills move from the top to the bottom of the reactor by reason of the force of gravity in a partially dammed state.
Claim 22
Dependent Claim
26 words
A porous pill as specified in claim 3 wherein said porous pill has a density which is within the range of about 70% to about 96%.
Claim 23
Dependent Claim
25 words
A porous pill as specified in claim 3 wherein said porous pill has a density which is within the range of about 85% to 93%.
Claim 24
Dependent Claim
16 words
A process as specified in claim 1 wherein the porous pills are made utilizing extrusion equipment.
Claim 25
Dependent Claim
18 words
A porous pill as specified in claim 3 wherein said compaction is done by utilizing a briquetting system.
Claim 26
Dependent Claim
17 words
A process as specified in claim 1 wherein the porous pill is made utilizing a briquetting system.
Claim 27
Dependent Claim
138 words
A porous pill which can be solid state polymerized at a very rapid rate into a high molecular weight polyester resin wherein said porous pill is comprised of a polyester prepolymer having an intrinsic viscosity of at least about 0.1 dl/g in a 60:40 phenol:tetrachloroethane solvent system at a temperature of 30° C. and at a concentration of 0.4 g/dl; wherein said porous pill contains a substantial volume of interstices which penetrates the porous pill and open to the outside; wherein the porous pill has a density which is within the range of about 70% to about 99% of the density of solid polyester pellets which are comprised of the same polyester prepolymer; and wherein the porous pill is made by agglomerating a powder of the polyester prepolymer having a particle size of less than about 841 microns.
Claim 28
Dependent Claim
138 words
A porous pill which can be solid state polymerized at a very rapid rate into a high molecular weight polyester resin wherein said porous pill is comprised of a polyester prepolymer having an intrinsic viscosity of at least about 0.1 dl/g in a 60:40 phenol:tetrachloroethane solvent system at a temperature of 30° C. and at a concentration of 0.4 g/dl; wherein said porous pill contains a substantial volume of interstices which penetrates the porous pill and open to the outside; wherein the porous pill has a density which is within the range of about 70% to about 99% of the density of solid polyester pellets which are comprised of the same polyester prepolymer; and wherein the porous pill is made by agglomerating a powder of the polyester prepolymer having a particle size of less than about 841 microns.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1992-10-23 | 1993-04-24 | 1993-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-23 | 1997-04-24 | 1997-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-23 | 2001-04-24 | 2001-10-24 | $7700.00 | Window Closed / Lapsed |