US4139518A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polyethylene terephthalate composition and shaped articles
Assignee: Hoechst AG
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Filing: 1977-07-22
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Granted: 1979-02-13
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Expires: 1997-07-22
Abstract
Abstract Disclosed is a composition, comprising a calcium-containing polyethylene terephthalate polymer and from about 0.01 to 1% by weight of silica obtained by a pyrogenic process, as well as a method of producing same and improved shaped articles made from said composition.
Inventors
- 👤 Siegfried Janocha
- 👤 Manfred Unger
- 👤 Klaus Hoheisel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 09:20
CPC Classifications
C; C07; C07C; C07C309/00; C08; C08G; C08G63/00; C08G63/78; C08G63/82; C08G63/83; C08K; C08K3/00; C08K3/34; C08K3/36; Y; Y10; Y10S; Y10S260/00; Y10S260/35
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
84 words
A polyester composition characterized by enhanced melt filterability properties and being adapted for producing biaxially oriented film products having improved depth of roughness values and low values for short wave length irregularities in film thickness, said composition consisting essentially of a polyethylene terephthalate polymer, calcium in the form of a salt which is capable of catalyzing the transesterification reaction between dimethyl terephthalate and ethylene glycol, and an amount sufficient to enhance the melt filterability of the composition of silica obtained by a pyrogenic process.
Claim 2
Dependent Claim
84 words
A polyester composition characterized by enhanced melt filterability properties and being adapted for producing biaxially oriented film products having improved depth of roughness values and low values for short wave length irregularities in film thickness, said composition consisting essentially of a polyethylene terephthalate polymer, calcium in the form of a salt which is capable of catalyzing the transesterification reaction between dimethyl terephthalate and ethylene glycol, and an amount sufficient to enhance the melt filterability of the composition of silica obtained by a pyrogenic process.
Claim 3
Dependent Claim
23 words
The composition as defined by claim 1, wherein the amount of silica is between about 0.01 and 1% by weight of the composition.
Claim 4
Dependent Claim
23 words
The composition as defined by claim 1, wherein the amount of silica is between about 0.1 and 0.6% by weight of the composition.
Claim 5
Dependent Claim
20 words
The composition as defined by claim 1, wherein said pyrogenic silica is produced by pyrogenic treatment of a silicon halide.
Claim 6
Dependent Claim
26 words
The composition as defined by claim 4, wherein said pyrogenic silica is produced by hydrolysis at an elevated temperature of SiCl 4 in a gaseous phase.
Claim 7
Dependent Claim
23 words
The composition as defined by claim 1, wherein said pyrogenic silica comprises an average particle size of between about 5 and 50 millimicrons.
Claim 8
Dependent Claim
23 words
The composition as defined by claim 6, wherein said pyrogenic silica comprises an average particle size of between about 20 and 50 millimicrons.
Claim 9
Dependent Claim
27 words
The composition as defined by claim 7, wherein said pyrogenic silica comprises a BET surface area per mass of between about 150 and 250 m 2 /g.
Claim 10
Dependent Claim
14 words
The composition as defined by claim 1, wherein said calcium salt comprises calcium acetate.
Claim 11
Dependent Claim
27 words
The composition as defined by claim 1, wherein said calcium salt is present in the polyethylene terephthalate in an amount between about 0.01 and 0.1% by weight.
Claim 12
Dependent Claim
84 words
A process for preparing the composition as defined by claim 1, comprising the steps of conducting a transesterification reaction between ethylene glycol and a lower alkyl ester of terephthalic acid in the presence of a catalytically active calcium salt for said reaction, whereby an ester is produced, subjecting said ester to polyester condensation reaction conditions, and incorporating an amount of said pyrogenic silica effective to enhance the melt filterability of the composition at a point in the process not subsequent to said condensation reaction.
Claim 13
Dependent Claim
21 words
The process as defined by claim 11, wherein said pyrogenic silica is incorporated prior to the beginning of said esterification reaction.
Claim 14
Dependent Claim
17 words
The process as defined by claim 12, wherein said pyrogenic silica is contained in said ethylene glycol.
Claim 15
Dependent Claim
17 words
The process as defined by claim 11, wherein said pyrogenic silica is added during said esterification reaction.
Claim 16
Dependent Claim
21 words
The process as defined by claim 14, wherein said pyrogenic silica is added shortly after the beginning of said esterification reaction.
Claim 17
Dependent Claim
11 words
A shaped article, comprising the composition as defined by claim 1.
Claim 18
Dependent Claim
11 words
A shaped article, comprising the composition as defined by claim 2.
Claim 19
Dependent Claim
11 words
A shaped article, comprising the composition as defined by claim 4.
Claim 20
Dependent Claim
29 words
A stretched film characterized by improved values for depth of roughness and low values for shortwave length irregularities in film thickness, comprising the composition as defined by claim 1.
Claim 21
Dependent Claim
29 words
A stretched film characterized by improved values for depth of roughness and low values for shortwave length irregularities in film thickness, comprising the composition as defined by claim 2.
Claim 22
Dependent Claim
29 words
A stretched film characterized by improved values for depth of roughness and low values for shortwave length irregularities in film thickness, comprising the composition as defined by claim 4.
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) | 1982-02-12 | 1982-08-14 | 1983-02-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-02-12 | 1986-08-14 | 1987-02-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-02-12 | 1990-08-14 | 1991-02-13 | $7700.00 | Window Closed / Lapsed |