Cure rate control in epoxy resin compositions

• US 4,668,758 A
• Filed: 09/30/1985
• Issued: 05/26/1987
• Est. Priority Date: 09/30/1985
• Status: Expired due to Fees

• Current Assignee: Shell Oil Company (Shell Plc)
• Original Assignee: Shell Oil Company (Shell Plc)
• Inventors: Corley, Larry S.
• Primary Examiner(s): Nielsen, Earl
• Application Number:
  US06/782,750
• Time in Patent Office: 603 Days
• Field of Search: 528/88, 528/89, 528/90, 528/91, 528/92, 528/408, 528/409, 528/416, 528/413
• US Class Current: 528/91
• CPC Class Codes: C08G 59/18 Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
• CPC Class Codes: C08G 59/68 characterised by the catalysts used

Abstract

An epoxy resin composition containing a cationic curing agent and a cure-retarding amount of a diarylamine. The diarylamine lengthens the pot life of the epoxy-curing agent composition.

Claims

1. A composition comprising:

(a) an epoxy resin;

(b) a cationic curing agent for the epoxy resin selected from the group consisting of protonic acids having anions of low nucleophilicity and metal salts of such protonic acids; and

(c) a diarylamine present in an amount effective to retard cure of the epoxy resin by the curing agent.

2. The composition of claim 1 in which the curing agent is selected from the group consisting of HBF₄, HPF₆, HSbF₆, CF₃ SO₃ H, H₂ SO₄, Sn(BF₄)₂, Al(BF₄)₃ and Mg(BF₄)₂.

3. The composition of claim 1 in which the diarylamine can be represented by the formula ##STR3## wherein each R and R'"'"' is selected independently from H, C₁ -C₁₀ alkyl, halogen, hydroxyl and ArNH--.

4. The composition of claim 3 in which the diarylamine is diphenylamine.

5. The composition of claim 3 in which the diarylamine is present in the composition in an amount of about 0.01 to about 20 weight percent, based on the weight of the epoxy resin.

6. The composition of claim 5 in which the curing agent is present in the composition in an amount of about 0.01 to about 10 weight percent, based on the weight of the epoxy resin.

7. The composition of claim 6 in which the epoxy resin is a reaction product of epichlorohydrin and bisphenol-A having a molecular weight of from about 340 to about 1500.

8. The composition of claim 7 which further comprises a surfactant.

16. The composition of claim 1 in which the curing agent is HBF4 and the diarylamine is an alkylated diphenylamine.

9. A method for retarding the cure of an epoxy resin by a cationic curing agent selected from the group consisting of HBF₄, HPF₆, HPF₆, HSbF₆, CF₃ SO₈ H, H₂ SO₄, Sn(BF₄)₃ and Mg(BF₄)₂ comprising incorporating in a mixture of the epoxy resin and the cationic curing agent from about 0.01 to about 20 weight percent, based on the weight ofthe epoxy resin, of a diarylamine.

10. The method of claim 9 is which the epoxy resin is a reaction product of epichlorohydrin and bisphenol-A having a molecular weight in the range of about 340 to about 1500.

11. The method of claim 9 in which the cationic curing agent is selected from the group consisting of HBF₄, HPF₆, HSbF₆, CF₃ SO₃ H, H₂ SO₄, Sn(BF₄)₃ and Mg(BF₄)₂.

12. The method of claim 11 in which the mixture of the epoxy resin and the cationic curing agent further comprises a surfactant.

13. The method of claim 11 in which the diarylamine can be represented by the formula ##STR4## wherein each R and each R'"'"' is selected independently from H, C₁ -C₁₀ alkyl, halogen, hydroxyl and ArNH--.

14. The method of claim 13 in which the diarylamine is mixed first with the epoxy resin and the resulting epoxy resin-diarylamine composition is then mixed with the cationic curing agent.

15. The method of claim 13 in which the cationic curing agent is present in an amount of from about 0.5 to about 5 weight percent and the diarylamine is present in an amount of about 1 to about 10 percent, based on the weight of the epoxy resin.

17. The method of claim 9 in which the curing agent is HBF4 and the diarylamine is an alkylated diphenylamine.