US4501878A
Expired / Lapsed
US
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Process for the preparation of high molecular weight polyesters
Assignee: Eastman Chemical Co
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Filing: 1984-01-30
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Granted: 1985-02-26
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Expires: 2004-01-30
Abstract
Abstract Disclosed is an improved process for the preparation of high molecular weight linear polyesters. In the preparation of polyesters by formation of a bis-dihydroxy ester prepolymer by transesterifying dimethyl terephthalate with a glycol in the presence of a catalyst followed by polycondensing the prepolymer in the presence of certain phosphorous-containing compounds and a transition metal-containing catalyst which remains active in the presence of said phosphorous compound, an improved rate of polycondensation is achieved by introducing the phosphorous compounds after first polycondensing the prepolymer to a low molecular weight linear polyester having an average degree of polymerization of about 2 to about 10. The improved process further requires that the catalyst employed in the formation of the prepolymer be substantially inactive in the presence of said phosphorous compounds.
Inventors
- 👤 L. Jane Adams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:08
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/78; C08G63/82; C08G63/85; C08G63/87
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
152 words
In the process for the preparation of high molecular weight linear polyester by the steps of (a) reacting dimethyl terephthalate with a glycol containing up to about 8 carbon atoms in the presence of a transesterification catalyst to form a bis-dihydroxy ester prepolymer, (b) polycondensing said prepolymer in the presence of one or more phosphorous-containing compounds and a transition metal containing polycondensation catalyst which is active in the presence of said phosphorous compound, the improvement comprising employing a transesterification catalyst which is substantially inactive in the presence of said phosphorous-containing compound and introducing said phosphorous compound into the polycondensation reaction zone after first polycondensing said prepolymer until a low molecular weight linear polyester having an average degree of polymerization of about 2 to about 10 is obtained and polycondensing in the presence of said phosphorous compound until a linear polyester having an inherent viscosity of about 0.35 to about 0.8 is obtained.
Claim 2
Dependent Claim
152 words
In the process for the preparation of high molecular weight linear polyester by the steps of (a) reacting dimethyl terephthalate with a glycol containing up to about 8 carbon atoms in the presence of a transesterification catalyst to form a bis-dihydroxy ester prepolymer, (b) polycondensing said prepolymer in the presence of one or more phosphorous-containing compounds and a transition metal containing polycondensation catalyst which is active in the presence of said phosphorous compound, the improvement comprising employing a transesterification catalyst which is substantially inactive in the presence of said phosphorous-containing compound and introducing said phosphorous compound into the polycondensation reaction zone after first polycondensing said prepolymer until a low molecular weight linear polyester having an average degree of polymerization of about 2 to about 10 is obtained and polycondensing in the presence of said phosphorous compound until a linear polyester having an inherent viscosity of about 0.35 to about 0.8 is obtained.
Claim 3
Dependent Claim
106 words
The process of claim 1 wherein the phosphorous-containing compound is selected from the group comprising phosphoric acid, salts of said acid, ethyl acid phosphate, diethyl acid phosphate, triethyl acid phosphate, aryl alkyl phosphate, tris-2-ethylhexyl phosphate and a phosphate ester having the formula ##STR2## wherein n has an average value of about 1.5 to about 3.0 and each R is hydrogen or an alkyl radical having from 6 to 10 carbon atoms, the ratio of the number of R groups of hydrogen atoms to the number of phosphorus atoms being about 0.25 to 0.50, and the ester has a free acidity equivalent of about 0.2 to 0.5.
Claim 4
Dependent Claim
28 words
The process of claim 1 wherein the transesterification catalyst comprises one or more catalysts selected from the group consisting of cobaltous acetate tetrahydrate, manganese acetate and zinc acetate.
Claim 5
Dependent Claim
13 words
The process of claim 1 wherein the polycondensation catalyst comprises an antimony compound.
Claim 6
Dependent Claim
11 words
The process of claim 4 wherein the antimony compound is antimony-III-acetate.
Claim 7
Dependent Claim
27 words
The process of claim 1 wherein the polycondensation catalyst comprises antimony and up to about 10 weight % titanium, based on the total weight of metal employed.
Claim 8
Dependent Claim
32 words
The process of claim 2 wherein the phosphorous-containing compound is present in the amount to provide phosphorous in the amount of about 0.5 to about 2.0 moles per mole of transesterification catalyst.
Claim 9
Dependent Claim
11 words
The process of claim 1 wherein the bis-dihydroxy ester is bis(2-hydroxyethyl)terephthalate.
Claim 10
Dependent Claim
28 words
The process of claim 1 wherein the glycol comprises ethylene glycol, from 0 to about 30 mole % 1,4-cyclohexanedimethanol, and up to about 5 mole % diethylene glycol.
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) | 1988-02-26 | 1988-08-27 | 1989-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-02-26 | 1992-08-27 | 1993-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-02-26 | 1996-08-27 | 1997-02-26 | $7700.00 | Window Closed / Lapsed |