US4073788A
Expired / Lapsed
US
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Partially imidized polyamide-acid polymers, aqueous coating compositions, coated wire and method, and partially imidized intermediate
Assignee: General Electric Co
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Filing: 1974-05-06
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Granted: 1978-02-14
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Expires: 1994-05-06
Abstract
Abstract The process for producing polyamide acid and polyimide polymers for use as coating materials by reacting an aromatic dianhydride reactant with an aromatic diamine reactant to produce a polyamide acid polymer wherein said reactants are present in approximately equal molar quantities, by utilizing the steps of forming an anhydrous mixture of an aromatic dianhydride reactant and an aromatic diamine reactant in an organic solvent wherein the reactants are in the molar ratio of about two-to-one, reacting said reactants at a temperature below that at which imidization occurs to form an amide acid intermediate having two free carboxyl groups each ortho to an amide group, and further reacting said amide acid intermediate with a reactant of the character of the original reactant initially present in the lesser amount with said additional reactant being in the molar amount equal to the molar amount of said lesser initial reactant thereby to form a polyamide acid polymer for use as a coating material. Additional steps may include the addition of a volatile ammonium base to produce a water soluble polyamide acid polymer and diluting the coating medium with water to form an aqueous-organic coating medium. The amide acid intermediate may be partially imidized and appropriate flow agents may be added. The coating medium is applied to a substrate to form a coating and the coating is cured to a polyimide form by the application of heat. The resulting product is a substrate with a polyimide coating.
Inventors
- 👤 Marvin A. Peterson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:28
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1003; C08G73/1007; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31678; Y10T428/31681
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
240 words
In a process for producing a high solids content polyamide acid solution for use in the preparation of a coating medium for applying a curable polyamide acid coating on magnet wire which includes the steps of reacting in a solvent an aromatic dianhydride reactant with an aromatic diamine reactant to produce a solution of a polyamide acid polymer wherein said reactants are present in approximately equal molar quantities, the improvement comprising: (a) forming an anhydrous mixture of an aromatic dianhydride reactant and an aromatic diamine reactant in an organic solvent wherein the reactants are in the molar ratio of about two-to-one; (b) reacting said reactants at a temperature below that at which imidization occurs to form an amide acid intermediate having two free carboxyl groups each ortho to an amide group; (c) partially imidizing said amide acid intermediate to an imidization level greater than a negligible amount up to but not more than 56% to provide the desired viscosity of the final polyamide acid polymer solution; (d) further reacting said amide acid intermediate with a reactant of the character of the original reactant initially present in the lesser amount with said additional reactant being in a molar amount equal to the molar amounts of said lesser initial reactant; (e) the total amounts of dianhydride reactant and diamine reactant being sufficient to produce a polyamide acid polymer solution having a solids content of between about 25% and about 70% by weight.
Claim 2
Dependent Claim
240 words
In a process for producing a high solids content polyamide acid solution for use in the preparation of a coating medium for applying a curable polyamide acid coating on magnet wire which includes the steps of reacting in a solvent an aromatic dianhydride reactant with an aromatic diamine reactant to produce a solution of a polyamide acid polymer wherein said reactants are present in approximately equal molar quantities, the improvement comprising: (a) forming an anhydrous mixture of an aromatic dianhydride reactant and an aromatic diamine reactant in an organic solvent wherein the reactants are in the molar ratio of about two-to-one; (b) reacting said reactants at a temperature below that at which imidization occurs to form an amide acid intermediate having two free carboxyl groups each ortho to an amide group; (c) partially imidizing said amide acid intermediate to an imidization level greater than a negligible amount up to but not more than 56% to provide the desired viscosity of the final polyamide acid polymer solution; (d) further reacting said amide acid intermediate with a reactant of the character of the original reactant initially present in the lesser amount with said additional reactant being in a molar amount equal to the molar amounts of said lesser initial reactant; (e) the total amounts of dianhydride reactant and diamine reactant being sufficient to produce a polyamide acid polymer solution having a solids content of between about 25% and about 70% by weight.
Claim 3
Dependent Claim
41 words
The process defined in claim 1 wherein said amide acid intermediate is partially imidized by heating the solution thereof to between about 90° C. and about 110° C. for a period of time sufficient to effect the desired degree of imidization.
Claim 4
Dependent Claim
66 words
The process of claim 1 wherein said aromatic dianhydride is of the general formula ##STR23## where R is a tetravalent radical containing at least one ring of six carbon atoms and having benzenoid unsaturation and with each pair of carboxyl groups being attached to different carbon atoms, and wherein said aromatic diamine is of the general formula NH.sub.2 --R'--NH.sub.2 where R' is a divalent aromatic radical.
Claim 5
Dependent Claim
15 words
The process defined in claim 3 wherein said aromatic dianhydride is 3,3', 4,4' benzophenonetetracarboxylic dianhydride.
Claim 6
Dependent Claim
13 words
The process defined in claim 3 wherein said aromatic diamine is p,p'-methylene dianiline.
Claim 7
Dependent Claim
51 words
The process defined in claim 1 wherein the initial reactants are in the molar ratio of two moles of aromatic diamine to one mole of aromatic dianhydride to form a stable amide acid intermediate material having two free carboxyl groups each ortho to an amide group and two terminal amine groups.
Claim 8
Dependent Claim
56 words
The process defined in claim 1 wherein the improvement further comprises the steps of adding ammonia to the high solids content organic solution of said polyamide acid polymer and thereafter further diluting said organic ammonium polyorthoamate solution with water to form a stable aqueous-organic coating medium having a solids content suitable for the intended coating application.
Claim 9
Dependent Claim
24 words
The process defined in claim 7 wherein the improvement further comprises the step of adding a flow promoting agent to the aqueous-organic coating medium.
Claim 10
Dependent Claim
40 words
The process in accordance with claim 1 in which said aromatic dianhydride is selected from the group consisting of 3,3',4,4' benzophenonetetracarboxylic dianhydride, pyromellitic dianhydride, and cyclopentane tetracarboxylic dianhydride and said aromatic diamine is selected from the group consisting of: m-phenylenediamine
Claim 11
Dependent Claim
42 words
4'-oxydianiline 4,4'-sulfonyldianiline 4,4'-methylenedianiline 4,4'-diamino-diphenyl sulfide 3,3'-diamino-diphenyl sulfone 4,4'-diamino-diphenyl ether 2,6-diamino pyridine bis-(4 amino-phenyl) diethyl silane bis-(4 amino-phenyl) phosphine oxide bis-(4 amino-phenyl)-N-methylamine 1,5-diamino naphthalene 3,3'-dimethyl-4,4'-diamino-biphenyl 3,3'-dimethoxy benzidine m-xylylene diamine p-xylylene diamine 1,3-bis-delta amino butyltetramethyl disiloxane and 1,3-bis-gamma-amino propyl tetraphenyl disiloxane and mixtures thereof.
Claim 12
Dependent Claim
42 words
4'-oxydianiline 4,4'-sulfonyldianiline 4,4'-methylenedianiline 4,4'-diamino-diphenyl sulfide 3,3'-diamino-diphenyl sulfone 4,4'-diamino-diphenyl ether 2,6-diamino pyridine bis-(4 amino-phenyl) diethyl silane bis-(4 amino-phenyl) phosphine oxide bis-(4 amino-phenyl)-N-methylamine 1,5-diamino naphthalene 3,3'-dimethyl-4,4'-diamino-biphenyl 3,3'-dimethoxy benzidine m-xylylene diamine p-xylylene diamine 1,3-bis-delta amino butyltetramethyl disiloxane and 1,3-bis-gamma-amino propyl tetraphenyl disiloxane and mixtures thereof.
Claim 13
Dependent Claim
40 words
The process in accordance with claim 1 wherein the reaction is carried out within an anhydrous organic solvent, said solvent having functional groups which are nonreactive with the reactants and being a solvent for at least one of said reactants.
Claim 14
Dependent Claim
38 words
The process of coating a substrate which comprises applying the polyamide acid produced according to the process defined in claim 1 to a substrate, and heating said coated substrate to cure said coating to the polyimide polymer form.
Claim 15
Dependent Claim
23 words
The process defined in claim wherein said coated substrate is heated to a temperature of between about 100° C. and about 500° C.
Claim 16
Dependent Claim
10 words
The process of claim 12 wherein the substrate is wire.
Claim 17
Dependent Claim
19 words
A substrate coated with a cured coating of coating material produced according to the process defined in claim 1.
Claim 18
Dependent Claim
20 words
Magnet wire coated with a cured coating of a coating material produced according to the process defined in claim 1.
Claim 19
Dependent Claim
270 words
A process for coating magnet wire with a polyamide acid coating comprising the steps of: (a) forming an anhydrous reaction mixture of an aromatic dianhydride type reactant and an aromatic diamine type reactant in an anhydrous solvent which is substantially inert to said reactants and wherein said reactants are in the molar ratio of about two-to-one; (b) reacting said reactants at a temperature below about 80° C. and for a period of time sufficient to form a prepolymeric reaction product; (c) partially imidizing said prepolymeric reaction product to an imidization level greater than a negligible amount up to but not more than 56% to provide the desired viscosity of the polyamide acid coating medium; (d) reacting said prepolymeric reaction product with a further amount of a reactant of the type of the one of said reactants which was present in the lesser amount in the reaction mixture, with said prepolymeric reaction product and said further reactant being in the molar ratio of about one-to-one, at a temperature of below about 80° C. to produce a solution of a polyamide acid reaction product having a solids content of between about 25% and about 70% by weight; (e) reacting said polyamide acid reaction product with a volatile ammonium base to render said reaction product water soluble; (f) adding water to said ammoniated reaction product in an amount sufficient to form an aqueous-organic solution thereof having a solids content suitable for the intended coating application; (g) adding to said aqueous-organic solution a flow control agent to form a coating medium; and (h) applying a coating of said coating medium to the magnet wire.
Claim 20
Dependent Claim
270 words
A process for coating magnet wire with a polyamide acid coating comprising the steps of: (a) forming an anhydrous reaction mixture of an aromatic dianhydride type reactant and an aromatic diamine type reactant in an anhydrous solvent which is substantially inert to said reactants and wherein said reactants are in the molar ratio of about two-to-one; (b) reacting said reactants at a temperature below about 80° C. and for a period of time sufficient to form a prepolymeric reaction product; (c) partially imidizing said prepolymeric reaction product to an imidization level greater than a negligible amount up to but not more than 56% to provide the desired viscosity of the polyamide acid coating medium; (d) reacting said prepolymeric reaction product with a further amount of a reactant of the type of the one of said reactants which was present in the lesser amount in the reaction mixture, with said prepolymeric reaction product and said further reactant being in the molar ratio of about one-to-one, at a temperature of below about 80° C. to produce a solution of a polyamide acid reaction product having a solids content of between about 25% and about 70% by weight; (e) reacting said polyamide acid reaction product with a volatile ammonium base to render said reaction product water soluble; (f) adding water to said ammoniated reaction product in an amount sufficient to form an aqueous-organic solution thereof having a solids content suitable for the intended coating application; (g) adding to said aqueous-organic solution a flow control agent to form a coating medium; and (h) applying a coating of said coating medium to the magnet wire.
Claim 21
Dependent Claim
120 words
The coating process defined in claim 16 wherein said flow control agent is selected from the group consisting of: (a) a flow agent surfactant in the amount of between about 0.6% and about 0.6% and about 0.7% by weight of the coating medium, (b) a fluorocarbon surfactant in the amount of about 100 parts per million by weight of the coating medium, (c) a carboxypropyl terminated dimethyl siloxane polymer flow agent in the amount of 100 parts per million by weight of the coating medium, and (d) a mixture of cresylic acid-phenol blend in the amount of about 6% by weight of the coating medium, and n-butyl alcohol in the amount of about 6% by weight of the coating medium.
Claim 22
Dependent Claim
30 words
The coating process defined in claim 16 wherein the flow control agent is nonylphenoxypoly(ethyleneoxy)ethanol in the amount of between about 0.6% and about 0.7% by weight of the coating medium.
Claim 23
Dependent Claim
41 words
The coating process defined in claim 16 wherein the flow control agent is cresylic acid-phenol blend in the amount of 6% by weight of the coating medium and n-butyl alcohol in the amount of 6% by weight of the coating medium.
Claim 24
Dependent Claim
32 words
The coating process defined in claim 16 wherein the flow control agent is carboxypropyl terminated siloxane polymer in the amount of about 100 parts per million by weight of the coating medium.
Claim 25
Dependent Claim
26 words
The coating process defined in claim 16 wherein the flow control agent is fluorocarbon surfactant in the amount of about 100 parts per million by weight.
Claim 26
Dependent Claim
13 words
The coating process defined in claim 16 wherein said substrate is magnet wire.
Claim 27
Dependent Claim
14 words
The coating process defined in claim 22 wherein said magnet wire is copper wire.
Claim 28
Dependent Claim
14 words
The coating process defined in claim 22 wherein said magnet wire is aluminum wire.
Claim 29
Dependent Claim
32 words
The coating process defined in claim 16 wherein the polyamide acid reaction product is present in the coating medium in a concentration of between about 17% and about 22% solids by weight.
Claim 30
Dependent Claim
31 words
The coating process defined in claim 16 including the step of heating the coated substrate to a temperature and for a time sufficient to effect imidization of the polyamide acid coating.
Claim 31
Dependent Claim
19 words
The coating process defined in claim 16 wherein said temperature is between about 100° C. and about 500° C.
Claim 32
Dependent Claim
21 words
The coating process defined in claim 16 wherein the reaction temperature in steps (b) and (d) is below about 50° C.
Claim 33
Dependent Claim
36 words
The coating process defined in claim 16 wherein the maximum reaction temperature in step (b) is about 35° C. and the reaction temperature in step (d) is maintained between about 25° C. and about 45° C.
Claim 34
Dependent Claim
43 words
The coating process defined in claim 16 wherein said partial imidization is effected by heating said prepolymeric reaction product to a temperature between about 90° C. and about 110° C for a period of time sufficient to produce the desired level of imidization.
Claim 35
Dependent Claim
22 words
The coating process defined in claim 16 wherein said aromatic dianhydride reactant is 3,3',4,4'-benzophenonetetracarboxylic dianhydride and said aromatic diamine is p,p'-methylene dianiline.
Claim 36
Dependent Claim
69 words
The coating process defined in claim 30 wherein said aromatic dianhydride reactant is 3,3',4,4'-benzophenonetetracarboxylic dianhydride, said aromatic diamine is p,p'-methylene dianiline, said solvent is N-methyl-2-pyrrolidone, said reactants are initially reacted in the ratio of two moles 3,3',4,4'-benzophenonetetracarboxylic dianhydride and one mole p,p'-methylene dianiline, and said prepolymeric reaction product is heated at a temperature of about 95° C. for a period of about 100 minutes to partially imidize said product.
Claim 37
Dependent Claim
95 words
A stable amide acid intermediate composition for use in preparing a high solids content polyamide acid coating composition, comprising the reaction product of an aromatic diamine reactant and an aromatic dianhydride reactant in an anhydrous organic solvent, wherein the reactants are in the molar ratio of about two moles of one reactant to about one mole of the other and wherein said product is partially imidized to a level greater than a negligible amount up to but not more than 56% to provide the desired viscosity of the high solids content polyamide acid coating composition.
Claim 38
Dependent Claim
95 words
A stable amide acid intermediate composition for use in preparing a high solids content polyamide acid coating composition, comprising the reaction product of an aromatic diamine reactant and an aromatic dianhydride reactant in an anhydrous organic solvent, wherein the reactants are in the molar ratio of about two moles of one reactant to about one mole of the other and wherein said product is partially imidized to a level greater than a negligible amount up to but not more than 56% to provide the desired viscosity of the high solids content polyamide acid coating composition.
Claim 39
Dependent Claim
68 words
The intermediate composition defined in claim 33 wherein said aromatic dianhydride is of the general formula ##STR24## where R is a tetravalent radical containing at least one ring of six carbon atoms and having benzenoid unsaturation and with each pair of carboxyl groups being attached to different carbon atoms, and wherein said aromatic diamine is of the general formula NH.sub.2 --R'--NH.sub.2 where R' is a divalent aromatic radical.
Claim 40
Dependent Claim
22 words
The intermediate composition defined in claim 33 wherein said aromatic dianhydride is 3,3',4,4' benzophenonetetracarboxylic dianhydride and said aromatic diamine is p,p'-methylene dianiline.
Claim 41
Dependent Claim
52 words
The intermediate composition defined in claim 33 wherein the initial reactants are in the molar ratio of two moles of aromatic diamine to one mole of aromatic dianhydride to form a stable amide acid intermediate material having two free carboxyl groups each ortho to an amide group, and two terminal amine groups.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-02-13 | 1981-08-15 | 1982-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-13 | 1985-08-15 | 1986-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-13 | 1989-08-15 | 1990-02-14 | $7700.00 | Window Closed / Lapsed |