US4268656A
Expired / Lapsed
US
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Co-curing agents for epoxy resins
Assignee: Ingredion Inc
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Filing: 1980-01-16
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Granted: 1981-05-19
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Expires: 2000-01-16
Abstract
Abstract A N-substituted piperazine or N-substituted homopiperazine adduct with a polyepoxide is used as a co-curing agent in epoxy resin systems containing a polyepoxide and a known curing agent such as dicyandiamide, a carboxylic acid anhydride, or a dihydrazide. The preferred adducts have a ratio of epoxy groups to secondary amino groups of between 1.2:1 and 3:1. The preferred polyepoxides are polyglycidyl ethers of 4,4'-isopropylidenediphenol (bisphenol A). Suitable adducts are prepared from N-methyl-, N-(2-hydroxyethyl)-, N-octyl-, N-phenyl- and N-benzyl piperazine and N-methyl homopiperazine.
Inventors
- 👤 Dilip K. Ray-Chaudhuri
- 👤 Wen B. Chiao
- 👤 Jules E. Schoenberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:07
CPC Classifications
C; C08; C08G; C08G59/00; C08G59/18; C08G59/40; C08G59/4007; C08G59/4014; C08G59/4021; C08G59/182; C08G59/184; C08G59/4035; C08G59/50; C08G59/5046; C08G59/5053; C08G59/5073
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
97 words
A unitary, storable, heat-curable epoxy resin system, which comprises a polyepoxide and a curing amount of a combination comprising (1) an epoxy curing agent and (2) a co-curing agent prepared by reacting (a) a polyepoxide with (b) a N-substituted piperazine or a N-substituted homopiperazine, wherein said piperazine is substituted with an alkyl, substituted alkyl, cycloalkyl, aryl or aralkyl group of up to 12 carbon atoms and said homopiperazine is substituted with an alkyl group of up to 3 carbon atoms, said co-curing agent having a ratio of epoxy groups to secondary amino groups of at least 0.8:1.
Claim 2
Dependent Claim
97 words
A unitary, storable, heat-curable epoxy resin system, which comprises a polyepoxide and a curing amount of a combination comprising (1) an epoxy curing agent and (2) a co-curing agent prepared by reacting (a) a polyepoxide with (b) a N-substituted piperazine or a N-substituted homopiperazine, wherein said piperazine is substituted with an alkyl, substituted alkyl, cycloalkyl, aryl or aralkyl group of up to 12 carbon atoms and said homopiperazine is substituted with an alkyl group of up to 3 carbon atoms, said co-curing agent having a ratio of epoxy groups to secondary amino groups of at least 0.8:1.
Claim 3
Dependent Claim
31 words
The system of claim 1, wherein said polyepoxides are aromatic polyepoxides and said co-curing agent has a mole ratio of epoxy groups to secondary amino groups of between 1.2:1 and 3:1.
Claim 4
Dependent Claim
23 words
The system of claim 2, wherein said polyepoxides are glycidyl polyethers of 4,4'-isopropylidenediphenol having an epoxide equivalent weight of from 175 to 4000.
Claim 5
Dependent Claim
12 words
The system of claim 1, wherein said epoxy curing agent is dicyandiamide.
Claim 6
Dependent Claim
15 words
The system of claim 1, wherein said epoxy curing agent is a carboxylic acid ahydride.
Claim 7
Dependent Claim
22 words
The system of claim 5, wherein said carboxylic acid anhydride is 1,2-cyclohexane dicarboxylic acid anhydride, succinic anhydride, phthalic anhydride, or bicyclo(2.2.1)-heptene-2,3-dicarboxylic anhydride.
Claim 8
Dependent Claim
13 words
The system of claim 1, wherein said epoxy curing agent is a dihydrazide.
Claim 9
Dependent Claim
14 words
The system of claim 7, wherein said dihydrazide is azelayl dihydrazide or isophthalyl dihydrazide.
Claim 10
Dependent Claim
67 words
The system of claim 1, wherein said co-curing agent is prepared from a glycidyl polyether of 4,4'-isopropylidenediphenol having an epoxide equivalent of from 175 to 600 and and a compound selected from the group consisting of N-methyl piperazine, N-(2-hydroxyethyl) piperazine, N-octyl piperazine, N-phenyl piperazine, N-benzyl piperazine, and N-methyl homopiperazine, said co-curing agent being employed in amounts of from 0.05 to 20% by weight, based on said polyepoxide.
Claim 11
Dependent Claim
24 words
The system of claim 9, wherein said co-curing agent is employed in amounts of from 0.5 to 10% by weight, based on said polyepoxide.
Claim 12
Dependent Claim
125 words
A process for converting a polyepoxide into an insoluble, infusible product, which comprises heating said polyepoxide at an elevated temperature with a curing amount of a combination comprising (1) an epoxy curing agent and (2) a co-curing agent prepared by reacting (a) a polyepoxide with (b) a N-substituted piperazine or a N-substituted hompiperazine, wherein said piperazine is substituted with an alkyl, substituted alkyl, cycloalkyl, aryl or aralkyl group of up to 12 carbon atoms and said homopiperazine is substituted with an alkyl group of up to 3 carbon atoms and said co-curing agent has a ratio of epoxy groups to secondary amino groups of at least 0.8:1, said heating taking place at a temperature above 50° C. for a time sufficient to complete the cure.
Claim 13
Dependent Claim
125 words
A process for converting a polyepoxide into an insoluble, infusible product, which comprises heating said polyepoxide at an elevated temperature with a curing amount of a combination comprising (1) an epoxy curing agent and (2) a co-curing agent prepared by reacting (a) a polyepoxide with (b) a N-substituted piperazine or a N-substituted hompiperazine, wherein said piperazine is substituted with an alkyl, substituted alkyl, cycloalkyl, aryl or aralkyl group of up to 12 carbon atoms and said homopiperazine is substituted with an alkyl group of up to 3 carbon atoms and said co-curing agent has a ratio of epoxy groups to secondary amino groups of at least 0.8:1, said heating taking place at a temperature above 50° C. for a time sufficient to complete the cure.
Claim 14
Dependent Claim
22 words
The process of claim 11, wherein said polyepoxides are glycidyl polyethers of 4,4'-isopropylidenediphenol having an epoxide equivalent of from 175 to 4000.
Claim 15
Dependent Claim
12 words
The process of claim 11, wherein said epoxy curing agent is dicyandiamide.
Claim 16
Dependent Claim
33 words
The process of claim 11, wherein said epoxy curing agent is a carboxylic acid anhydride selected from the group consisting of 1,2-cyclohexane dicarboxylic acid anhydride, succinic anhydride, phthalic anhydride, and bicyclo (2.2.1)-heptene-2,3-dicarboxylic anhydride.
Claim 17
Dependent Claim
24 words
The process of claim 11, wherein said epoxy curing agent is a dihydrazide selected from the group consisting of azelayl dihydrazide and isophthalyl dihydrazide.
Claim 18
Dependent Claim
84 words
The process of claim 11, wherein said co-curing agent is prepared from a glycidyl polyether of 4,4'-isopropylidenediphenol having an epoxide equivalent of from 175 to 600 and a compound selected from the group consisting of N-methyl piperazine, N-(2-hydroxyethyl) piperazine, N-octyl piperazine, N-phenyl piperazine, N-benzyl piperazine, and N-methyl homopiperazine, said co-curing agent has a mole ratio of epoxy groups to secondary amino groups of between 1.2:1 and 1:3, and said co-curing agent is employed in amounts of from 0.05 to 20%, based on said polyepoxide.
Claim 19
Dependent Claim
22 words
The process of claim 16, wherein said co-curing agent is employed in amounts of from 0.5 to 10%, based on said polyepoxide.
Claim 20
Dependent Claim
94 words
A process for making a thermoset article of manufacture using a heat-curable epoxy resin adhesive comprising a polyepoxide, an epoxy curing agent, and a co-curing agent prepared by reacting (a) a polyepoxide with (b) a N-substituted piperazine or a N-substituted homopiperazine, wherein said piperazine is substituted with an alkyl, substituted alkyl, cycloalkyl, aryl or aralkyl group of up to 12 carbon atoms and said homopiperazine is substituted with an alkyl group of up to 3 carbon atoms, said co-curing agent having a ratio of epoxy groups to secondary amino groups of at least 0.8:1.
Claim 21
Dependent Claim
94 words
A process for making a thermoset article of manufacture using a heat-curable epoxy resin adhesive comprising a polyepoxide, an epoxy curing agent, and a co-curing agent prepared by reacting (a) a polyepoxide with (b) a N-substituted piperazine or a N-substituted homopiperazine, wherein said piperazine is substituted with an alkyl, substituted alkyl, cycloalkyl, aryl or aralkyl group of up to 12 carbon atoms and said homopiperazine is substituted with an alkyl group of up to 3 carbon atoms, said co-curing agent having a ratio of epoxy groups to secondary amino groups of at least 0.8:1.
Claim 22
Dependent Claim
109 words
The process of claim 18, wherein said polyepoxide is a glycidyl polyether of 4,4'-isopropylidenediphenol having an epoxide equivalent of from 175 to 4000; said epoxy curing agent is selected from the group consisting of dicyandiamide, 1,2-cyclohexane dicarboxylic acid anhydride, succinic anhydride, phthalic anhydride, and bicyclo (2.2.1)-heptene-2,3-dicarboxylic anhydride; and said co-curing agent is prepared from a glycidyl polyether of 4,4'-isopropylidenediphenol having an epoxide equivalent of from 175 to 600 and a compound selected from the group consisting of N-methyl piperazine, N-(2-hydroxyethyl)-piperazine, N-octyl piperazine, N-phenyl piperazine, N-benzyl piperazine, and N-methyl homopiperazine and said co-curing agent has a mole ratio of epoxy groups to secondary amino groups of between 1.2:1 and 3:1.
Claim 23
Dependent Claim
95 words
A composition of matter, useful as a co-curing agent for polyepoxides, which comprises the reaction product of a glycidyl polyether of 4,4'-isopropylidenediphenol having an epoxide equivalent of from 175 to 600 with a N-substituted piperazine or a N-substituted homopiperazine, wherein said piperazine is substituted with an alkyl, substituted alkyl, cycloalkyl, aryl, or aralkyl group of up to 12 carbon atoms and said homopiperazine is substituted with an alkyl group of up to 3 carbon atoms, wherein said reaction product has a mole ratio of epoxy groups to secondary amino groups of between 0.8:1 and 4:1.
Claim 24
Dependent Claim
95 words
A composition of matter, useful as a co-curing agent for polyepoxides, which comprises the reaction product of a glycidyl polyether of 4,4'-isopropylidenediphenol having an epoxide equivalent of from 175 to 600 with a N-substituted piperazine or a N-substituted homopiperazine, wherein said piperazine is substituted with an alkyl, substituted alkyl, cycloalkyl, aryl, or aralkyl group of up to 12 carbon atoms and said homopiperazine is substituted with an alkyl group of up to 3 carbon atoms, wherein said reaction product has a mole ratio of epoxy groups to secondary amino groups of between 0.8:1 and 4:1.
Claim 25
Dependent Claim
28 words
The composition of matter of claim 20, wherein said piperazine is N-methyl piperazine, N-(2-hydroxyethyl) piperazine, N-octyl piperazine, N-phenyl piperazine or N-benzyl piperazine and said homopiperazine is N-methyl homopiperazine.
Claim 26
Dependent Claim
23 words
The process for preparing the composition of claim 20, which comprises mixing said glycidyl polyether with said N-substituted piperazine or said N-substituted homopiperazine.
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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) | 1984-05-18 | 1984-11-17 | 1985-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-05-18 | 1988-11-17 | 1989-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-05-18 | 1992-11-17 | 1993-05-19 | $7700.00 | Window Closed / Lapsed |