One component epoxy curing agents comprising hydroxyalkylamino cycloalkanes

Patent metadata

Field	Value
Publication number	US-10017603-B2
Application number	US-201715682306-A
Country	US
Kind code	B2
Filing date	Aug 21, 2017
Priority date	Feb 28, 2013
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

Liquid epoxy curing agents that have improved latency over conventional liquid curing agents while retaining the physical properties of the cured material are disclosed. These liquid curing agents can be used for curing epoxy resins, or in combination with dicyandiamide (DICY) based curing agents in order to accelerate DICY curing.

First claim

The invention claimed is:

1. A latent curing and heat activated composition comprising: i) dicyandiamide, ii) at least one liquid tertiary amine salt curing agent accelerator having a viscosity of about 150 to about 200 cP, and iii) at least one epoxy resin; wherein the tertiary amine salt comprises a salt of at least one carboxylic acid and 1,4-bis(2-hydroxyethyl)piperazine, wherein the carboxylic acid comprises at least one member selected from the group consisting of acetic acid, propanoic acid, decanoic acid, dimer acid and mixtures thereof, wherein the amount of the curing agent accelerator ranges from about 1 phr to about 2 phr and wherein the composition is at least 85% cured when exposed to a temperature of 80° C. for 2 hours.

2. The composition of claim 1 wherein a cured composition has a Tg of about 90 to about 130° C.

3. The composition of claim 2 wherein the composition is substantially free of anhydrides and styrene and styrene containing compounds.

4. The composition of claim 1 wherein a cured composition has a flexural modulus when measured in accordance with ASTM C881 of about 14,000 to about 450,000 psi.

5. A cured epoxy resin obtained from the composition of claim 1 .

6. A latent heat curable composition consisting of: i) at least one epoxy resin, and ii) a curing agent consisting of dicyandiamide and a liquid carboxylic acid salt of 1,4-bis(2-hydroxyethyl)piperazine.

7. The composition of claim 6 wherein the composition is substantially free of anhydrides.

8. The composition of claim 6 wherein the ratio of amine to acid is about 1.0 to about 1.1.

9. The composition of claim 8 wherein the composition is at least 85% cured when exposed to a temperature of 80° C. for 2 hours.

10. The composition of claim 9 wherein the curing agent is between 5 weight percent and 7.4 weight percent of the composition.

11. The composition of claim 9 wherein the composition has a viscosity from about 6000 cp to about 20,000 cp for a period of about 2 days to about 8 days when measured at a temperature of 25° C.

12. The composition of claim 6 wherein the epoxy resin comprises bisphenol A diglycidyl ether.

13. The composition of claim 11 wherein the composition is cured when heated to a temperature of about 50 to about 150° C.

Assignees

• Evonik Degussa Gmbh

Inventors

• Lal Gauri Sankar
• Vedage Gamini Ananda
• Boyce Stephen Michael
• Shah Dilipkumar Nandlal
• Abdourazak Atteye Houssein

Classifications

• C08G59/506

  having one nitrogen atom in the ring · CPC title

• C08G59/56 Primary

  together with other curing agents · CPC title

• C08G59/42 Primary

  Polycarboxylic acids; Anhydrides, halides or low molecular weight esters thereof · CPC title

• C08G59/5073

  having two nitrogen atoms in the ring · CPC title

• C08G59/686

  containing nitrogen · CPC title