US4954609A
Expired / Lapsed
US
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Intermediate molecular weight fluorine containing polymide and method for preparation
Assignee: CNA Holdings LLC
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Filing: 1989-02-28
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Granted: 1990-09-04
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Expires: 2009-02-28
Abstract
Abstract The present invention provides a process for producing polyamic acids and polyimides having a controllable molecular weight and molecular weight distribution without the need to utilize end-capping agents in the polymerization process and without the need to stoichiometrically vary monomer ratios. The process of this invention involves subjecting a mixture of aromatic dianhydride and aromatic diamine monomers, at least one of which contains the group ##STR1## linking two aromatic moieties, wherein R is CF 3 or phenyl, to a low temperature, substantially isothermal solution polymerization process wherein the content of the mixed monomers in solvent is maintained within the range of from about 8 to about 12% by weight solids concentration during the polymerization process. The process is conducted for a sufficient length of time and uniformity of temperature, generally below about 35° C., to achieve a weight average polyimide polymer molecular weight within the range of about 80,000 to about 135,000, more preferably of about 90,000 to about 125,000, a polyimide inherent viscosity within the range of from about 0.45 to about 0.70, and a polydispersity with the range of from about 1.7 to about 2.6.
Inventors
- 👤 Rohitkumar H. Vora
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:54
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1003; C08G73/1007; C08G73/1028; C08G73/1039
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
226 words
A process for producing a polyimide polymer having recurring groups of the structure: ##STR6## wherein the moiety A is a tetravalent aromatic radical containing at least one benzene, naphthalene or poly-phenyl nucleus, the moiety B is a divalent aromatic group, and n is an integer ranging from about 100 to about 200, comprising: (a) forming a dispersion of an approximately equimolar mixture of an aromatic diamine monomer and an aromatic dianhydride monomer in organic solvent at the monomer solid level within the range of from about 8 to about 12% by weight, at least one of said monomers containing a ##STR7## group linking two aromatic moieties, wherein R is CF 3 or phenyl; (b) subjecting said monomer mixture to isothermal polymerization conditions in the absence of a monomer end capping agent to form a polyamic acid; and (c) cyclizing said polyamic acid to form a polyimide; said polymerization step being of sufficient length of time and uniformity of temperature to achieve a polyamide having a weight average molecular weight within the range of about 80,000 to about 135,000, an inherent viscosity within the range of from about 0.45 to about 0.70 as measured from a solution of the polymer in dimethyl acetamide at 25° C. at a polymer concentration of 0.5 weight percent, and a polydispersity within the range of from about 1.7 to about 2.6.
Claim 2
Dependent Claim
226 words
A process for producing a polyimide polymer having recurring groups of the structure: ##STR6## wherein the moiety A is a tetravalent aromatic radical containing at least one benzene, naphthalene or poly-phenyl nucleus, the moiety B is a divalent aromatic group, and n is an integer ranging from about 100 to about 200, comprising: (a) forming a dispersion of an approximately equimolar mixture of an aromatic diamine monomer and an aromatic dianhydride monomer in organic solvent at the monomer solid level within the range of from about 8 to about 12% by weight, at least one of said monomers containing a ##STR7## group linking two aromatic moieties, wherein R is CF 3 or phenyl; (b) subjecting said monomer mixture to isothermal polymerization conditions in the absence of a monomer end capping agent to form a polyamic acid; and (c) cyclizing said polyamic acid to form a polyimide; said polymerization step being of sufficient length of time and uniformity of temperature to achieve a polyamide having a weight average molecular weight within the range of about 80,000 to about 135,000, an inherent viscosity within the range of from about 0.45 to about 0.70 as measured from a solution of the polymer in dimethyl acetamide at 25° C. at a polymer concentration of 0.5 weight percent, and a polydispersity within the range of from about 1.7 to about 2.6.
Claim 3
Dependent Claim
11 words
The process of claim 1 wherein R is -CF 3 .
Claim 4
Dependent Claim
47 words
The process of claim 1 wherein at least one of said aromatic diamine monomer or aromatic dianhydride monomer is selected from the group consisting of 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride; 2,2-bis(3-aminophenyl) hexafluoropropane; 2,2-bis(4-aminophenyl) hexafluoropropane; 2(3-amino-phenyl)-2-(4-aminophenyl) hexafluoropropane, 2,2-hexafluoro-bis[4-(3-aminophenoxy) phenyl) propane; 2,2-hexafluoro-bis[4-(4-aminophenoxy) phenyl]propane; 1,1-bis-(4-aminophenyl)-1-phenyl-2, 2,2-trifluoroethane; 1,1-bis-[4-(1,2-dicarboxyphenyl)]-1-phenyl-2, 2,2-trifluoroethane dianhydride and mixtures thereof.
Claim 5
Dependent Claim
14 words
The process of claim 3 wherein said aromatic dianhydride monomer is 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride.
Claim 6
Dependent Claim
24 words
The process of claim 4 wherein said aromatic diamine is selected from the group consisting if 2,2-bis(3-aminophenyl) hexafluoropropane, 2,2-bis(4-aminophenyl) hexafluoropropane and 2-(3-aminophenyl) -2-(4-aminophenyl) hexafluoropropane.
Claim 7
Dependent Claim
12 words
The process of claim 5 wherein said aromatic diamine is 2,2-bis(4-aminophenyl) hexafluoropropane.
Claim 8
Dependent Claim
20 words
The process of claim 2 wherein said monomers are dispersed in solvent at a concentration of about 10% by weight.
Claim 9
Dependent Claim
25 words
The process of claim 2 wherein the weight average molecular weight of said polyimide polymer is within the range of about 90,000 to about 125,000.
Claim 10
Dependent Claim
10 words
A polyimide polymer produced by the process of claim 2.
Claim 11
Dependent Claim
75 words
A polyimide polymer produced by the process of claim 3 characterized as having an inherent viscosity within the range of from about 0.45 to about 0.70 as measured from a solution of the polymer in dimethylacetamide at 25° C. at a polymer concentration of 0.5 weight percent, a polydispersity within the range of from about 1.7 to about 2.6 and a weight average molecular weight within the range of from about 90,000 to about 125,000.
Claim 12
Dependent Claim
153 words
A method for controlling the molecular weight of a polyamide polymer having recurring groups of the structure of claim 1 within the weight average molecular weight range of from about 80,000 to about 135,000 without the use of monomer end capping agents comprising: (a) forming a dispersion of an approximately equimolar mixture of an aromatic diamine monomer and an aromatic dianhydride monomer in organic solvent; (b) subjecting said monomer mixture to isothermal polymerization conditions at a monomer solids level of from about 8 up to about 10% by weight to produce a polyamic acid polymer having a molecular weight on the lower side of said molecular weight range, or at a monomer solids level of from about 10 up to about 12% by weight to produce a polyamic acid polymer having a molecular weight on the higher side of said molecular weight range; and (c) cyclizing said polymeric acid to form a polyimide.
Claim 13
Dependent Claim
17 words
The method of claim 11 wherein said molecular weight range is from about 90,000 to about 125,000.
References Cited (Backward Citations)
GB1062435A
Cited
US4742152A
Cited
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