US4755587A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Solid state polymerization of polyester prepolymers
Assignee: Corpus Christi Polymers LLC
•
Filing: 1987-03-26
•
Granted: 1988-07-05
•
Expires: 2007-03-26
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. The present invention specifically relates to an improved process for solid state polymerizing a polyester prepolymer into a high molecular weight polyester resin comprising heating the polyester prepolymer to an elevated temperature which is sufficient to induce solid state polymerization, wherein the polyester prepolymer is in the form of porous pills. The porous pills utilized in such solid state polymerizations generally have a density within the range of about 70% to about 96% of the density of solid polyester pellets which are comprised of the polyester prepolymer and weigh from about 0.02 to about 0.5 grams.
Inventors
- 👤 Verne R. Rinehart
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:34
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/78; C08G63/80
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
61 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 polyester prepolymer has an intrinsic viscosity of less than 0.3 dl/g as measured in a 60/40 phenol/tetrachloroethane solvent system at 30° C.
Claim 2
Dependent Claim
61 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 polyester prepolymer has an intrinsic viscosity of less than 0.3 dl/g as measured in a 60/40 phenol/tetrachloroethane solvent system at 30° C.
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 compacting 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 compacting a powder of the polyester prepolymer having a particle size of less than about 841 microns.
Claim 5
Dependent Claim
103 words
In a solid state process for polymerizing low molecular weight polyester prepolymer to high molecular weight polyester resin, the improvement which comprises the use in said process of polyester prepolymer having an intrinsic viscosity of less than 0.3 dl/g as measured in a 60/40 phenol/tetrachloroethane solvent system at 30° C., therein said polyester prepolymer is in the form of discrete porous pills which have a density within the range of about 70% to about 96% of the density of solid polyester pellets which are comprised of said low molecular weight polyester prepolymer and wherein said porous pills weigh from 0.02 to 0.5 grams.
Claim 6
Dependent Claim
103 words
In a solid state process for polymerizing low molecular weight polyester prepolymer to high molecular weight polyester resin, the improvement which comprises the use in said process of polyester prepolymer having an intrinsic viscosity of less than 0.3 dl/g as measured in a 60/40 phenol/tetrachloroethane solvent system at 30° C., therein said polyester prepolymer is in the form of discrete porous pills which have a density within the range of about 70% to about 96% of the density of solid polyester pellets which are comprised of said low molecular weight polyester prepolymer and wherein said porous pills weigh from 0.02 to 0.5 grams.
Claim 7
Dependent Claim
32 words
A process as specified in claim 2 wherein said porous pills weigh from 0.02 grams to 0.5 grams and wherein said polyester prepolymer has an intrinsic viscosity of less than 0.3 dl/g.
Claim 8
Dependent Claim
38 words
A process as specified in claim 1 wherein the solid state polymerization is conducted in the presence of an inert gas and wherein said polyester prepolymer has an intrinsic viscosity within the range of 0.18 to 0.29 dl/g.
Claim 9
Dependent Claim
185 words
A process as specified in claim 2 wherein said polyester prepolymer is comprised of repeat units which are derived from a diacid component and a diol component; wherein said diacid component is at least one member selected from the group consisting of alkyl dicarboxylic acids which contain from 4 to 36 carbon atoms, diesters of alkyl dicarboxylic acids which contain from 6 to 38 carbon atoms, aryl dicarboxylic acids which contain from 8 to 20 carbon atoms, diesters of aryl dicarboxylic acids which contain from 10 to 22 carbon atoms, alkyl substituted aryl dicarboxylic acids which contain from 9 to 22 carbon atoms, or diesters of alkyl substituted aryl dicarboxylic acids which contain from 11 to 22 carbon atoms and wherein said diol component is at least one member selected from the group consisting of glycols containing from 2 to 12 carbon atoms, glycol ethers containing from 4 to 12 carbon atoms, and polyether glycols having the structural formula HO--A-O) n H wherein A is an alkylene group containing from 2 to 6 carbon atoms and wherein n is an integer from 2 to 400.
Claim 10
Dependent Claim
39 words
A process as specified in claim 6 wherein the density of said porous pills is within the range of 70% to 96% of the density of solid polyester pellets which are comprised of said low molecular weight polyester prepolymer.
Claim 11
Dependent Claim
17 words
A process as specified in claim 7 wherein said porous pills weigh from 0.02 to 0.5 grams.
Claim 12
Dependent Claim
14 words
A process as specified in claim 2 wherein said polyester prepolymer is polyethylene terephthalate.
Claim 13
Dependent Claim
37 words
A process as specified in claim 9 wherein the density of said porous pills is from 1.1 to 1.3 grams per cubic centimeter and wherein said polyester prepolymer has an intrinsic viscosity of less than 0.3 dl/g.
Claim 14
Dependent Claim
27 words
A process as specified in claim 10 wherein said process is carried out at a temperature within the range of about 210° C. to about 255° C.
Claim 15
Dependent Claim
56 words
A process as specified in claim 11 wherein the density of said porous pills is within the range of 85% to 93% of the density of solid polyester pellets which are comprised of said low molecular weight polyester prepolymer and wherein said polyester prepolymer has an intrinsic viscosity within the range of 0.18 to 0.29 dl/g.
Claim 16
Dependent Claim
19 words
A process as specified in claim 12 wherein said porous pills weigh from about 0.03 to about 0.2 grams.
Claim 17
Dependent Claim
22 words
A process as specified in claim 13 wherein said polymerization is carried out in the presence of at least one inert gas.
Claim 18
Dependent Claim
45 words
A process as specified in claim 14 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 19
Dependent Claim
21 words
A process as specified in claim 15 wherein said porous pills weigh within the range of 0.05 grams to 0.1 grams.
Claim 20
Dependent Claim
13 words
A process as specified in claim 16 wherein said inert gas is nitrogen.
Claim 21
Dependent Claim
79 words
A process as specified in claim 8 wherein said diacid component is at least one member selected from the group consisting of alkyl dicarboxylic acids containing from 4 to 12 carbon atoms; diesters of alkyl dicarboxylic acids containing from 6 to 12 carbon atoms; aryl dicarboxylic acids containing from 8 to 16 carbon atoms; diesters of aryl dicarboxylic acids containing from 10 to 18 carbon atoms; and alkyl substituted aryl dicarboxylic acids containing from 9 to 16 carbon atoms.
Claim 22
Dependent Claim
38 words
A process as specified in claim 18 wherein said porous pills have a density within the range of 85% to 93% of the density of solid polyester pellets which are comprised of said low molecular weight polyester prepolymer.
Claim 23
Dependent Claim
37 words
A process as specified in claim 19 wherein said solid state polymerization is carried out at a temperature within the range of about 5° C. to about 20° C. below the sticking temperature of said polyester prepolymer.
Claim 24
Dependent Claim
26 words
A process as specified in claim 16 wherein said polyester prepolymer is crystallized to a crystallinity of at least about 20% prior to solid state polymerization.
Claim 25
Dependent Claim
26 words
A process as specified in claim 20 wherein said polyester prepolymer is crystallized to a crystallinity of at least about 20% prior to solid state polymerization.
Claim 26
Dependent Claim
26 words
A process as specified in claim 9 wherein said polyester prepolymer is crystallized to a crystallinity of at least about 20% prior to solid state polymerization.
Claim 27
Dependent Claim
28 words
A process as specified in claim 17 wherein said polyester prepolymer is crystallized to a crystallinity within the range of 20% to 40% prior to solid state polymerization.
Claim 28
Dependent Claim
23 words
A process as specified in claim 21 wherein said polyester prepolymer has an intrinsic viscosity within the range of 0.2 to 0.28 dl/g.
Claim 29
Dependent Claim
31 words
A process as specified in claim 3 wherein said porous pills are made by compacting a powder of the polyester prepolymer having a particle size of less than about 841 microns.
Claim 30
Dependent Claim
33 words
A process as specified in claim 25 wherein said porous pills are made by compacting a powder of the polyester prepolymer having a particle size within the range of 20 to 60 mesh.
Claim 31
Dependent Claim
100 words
An improved process for solid state polymerizing a polyester prepolymer into a high molecular weight polyester resin which comprises: (1) crystallizing the polyester prepolymer, wherein the polyester prepolymer has an IV which is greater than about 0.3 dl/g; and (2) heating the polyester prepolymer which is in the form of porous pills to a temperature which is within the range of about 1° C. to about 50° C. below the sticking temperature of the polyester prepolymer, wherein said porous pills were made by compacting a powder of the polyester prepolymer having a particle size of less than about 841 microns.
Claim 32
Dependent Claim
100 words
An improved process for solid state polymerizing a polyester prepolymer into a high molecular weight polyester resin which comprises: (1) crystallizing the polyester prepolymer, wherein the polyester prepolymer has an IV which is greater than about 0.3 dl/g; and (2) heating the polyester prepolymer which is in the form of porous pills to a temperature which is within the range of about 1° C. to about 50° C. below the sticking temperature of the polyester prepolymer, wherein said porous pills were made by compacting a powder of the polyester prepolymer having a particle size of less than about 841 microns.
Claim 33
Dependent Claim
22 words
A process as specified in claim 26 wherein said compacting is done utilizing a pressure of at least about 1.379×10 7 Pascals.
Claim 34
Dependent Claim
31 words
A process as specified in claim 7 wherein said porous pills are made by compacting a powder of the polyester prepolymer having a particle size of less than about 841 microns.
Claim 35
Dependent Claim
31 words
A process as specified in claim 7 wherein said porous pills are made by agglomerating a powder of the polyester prepolymer having a particle size of less than about 841 microns.
Claim 36
Dependent Claim
22 words
A process as specified in claim 29 wherein said compacting is done utilizing a pressure of at least about 1.379×10 7 Pascals.
Claim 37
Dependent Claim
21 words
A process as specified in claim 12 wherein said porous pills are made by compacting a powder of the polyester prepolymer.
Claim 38
Dependent Claim
20 words
A process as specified in claim 33 wherein said powder has 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 |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-07-05 | 1992-01-04 | 1992-07-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-05 | 1996-01-04 | 1996-07-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-05 | 2000-01-04 | 2000-07-05 | $7700.00 | Window Closed / Lapsed |