Curing agents for low-emission epoxy resin products

Patent metadata

Field	Value
Publication number	US-9631047-B2
Application number	US-201314759538-A
Country	US
Kind code	B2
Filing date	Dec 20, 2013
Priority date	Jan 8, 2013
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

The present invention relates to curing agents for epoxy resins, containing at least one adduct of a primary diamine and an aromatic monoepoxide, at least one primary diamine and at least one secondary diamine which is free of primary amino groups and free of hydroxyl groups. The curing agent is of low viscosity and cures, together with epoxy resins, rapidly and without blushing, even under damp, cold conditions, to form films of high hardness and low brittleness. It is particularly well suited for low-emission coatings that cure at room temperature.

First claim

The invention claimed is:

1. A curing agent, suitable for curing epoxy resins, comprising:
at least one adduct of at least one primary diamine P1 and at least one aromatic monoepoxide, wherein the adduct is a reaction product of the at least one primary diamine P1 with the at least one aromatic monoepoxide in a ratio of moles of the at least one primary diamine P1 to moles of the at least one aromatic monoepoxide ranging from 1/1 to 1/1.5;
at least one primary diamine P2; and
at least one secondary diamine, which is 1,3-bis(2-ethylhexylaminomethyl)benzene or 1,3-bis(2-phenylethylaminomethyl)benzene.

2. The curing agent according to claim 1 , wherein the monoepoxide is a cresyl glycidyl ether.

3. The curing agent according to claim 1 , wherein the primary diamine P1 is selected from the group consisting of 1,6-hexanediamine, 1,5-diamino-2-methylpentane, 2,2,4- and 2,4,4-trimethylhexamethylenediamine, isophoronediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 2- and 4-methyl-1,3-diaminocyclohexane and mixtures thereof, and 1,3-bis(aminomethyl)benzene.

4. The curing agent according to claim 1 , wherein the adduct is a reaction product of 1,5-diamino-2-methylpentane with a cresyl glycidyl ether in a ratio of moles of the 1,5-diamino-2-methylpentane to moles of the cresyl glycidyl ether ranging from 1/1 to 1/1.2.

5. The curing agent according to claim 1 , wherein the primary diamine P2 has a molecular weight ranging from 140 to 300 g/mol, and is selected from the group consisting of isophoronediamine, 2,2,4- and 2,4,4-trimethylhexamethylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, bis(4-aminocyclohexyl)methane, bis(4-amino-3-methylcyclohexyl)methane, 4,7-dioxadecane-1,10-diamine, polyoxypropylenediamines and cycloaliphatic ether group-containing diamines from the propoxylation and subsequent amination of 1,4-dimethylolcyclohexane.

6. The curing agent according to claim 5 , wherein the primary diamine P2 is a polyoxypropylenediamine or a cycloaliphatic ether group-containing diamine from the propoxylation and subsequent amination of 1,4-dimethylolcyclohexane.

7. The curing agent according to claim 1 , wherein the ratios of the at least one adduct, the at least one primary diamine P2 and the at least one secondary diamine are such that, of the total number of amine hydrogens thereof that are reactive to epoxy groups,
15 to 75% are from the at least one adduct,
15 to 60% are from the at least one primary diamine P2, and
10 to 40% are from the at least one secondary diamine.

8. An epoxy resin composition containing at least one epoxy resin and at least one curing agent according to claim 1 .

9. The epoxy resin composition according to claim 8 , being a two-component composition, consisting of:
(i) a resin component containing at least one epoxy resin and
(ii) a curing agent component containing the curing agent.

10. A cured composition obtained by curing a composition according to claim 8 .

11. A curing agent, suitable for curing epoxy resins, comprising:
at least one adduct of at least one primary diamine P1 and at least one aromatic monoepoxide;
at least one primary diamine P2; and
at least one secondary diamine, which is 1,3-bis(2-ethylhexylaminomethyl)benzene or 1,3-bis(2-phenylethylaminomethyl)benzene.

12. The curing agent according to claim 11 , wherein the monoepoxide is a cresyl glycidyl ether.

13. The curing agent according to claim 12 , wherein the primary diamine P1 is selected from the group consisting of 1,6-hexanediamine, 1,5-diamino-2-methylpentane, 2,2,4- and 2,4,4-trimethylhexamethylenediamine, isophoronediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 2- and 4-methyl-1,3-diaminocyclohexane and mixtures thereof, and 1,3-bis(aminomethyl)benzene.

14. The curing agent according to claim 13 , wherein the adduct is a reaction product of 1,5-diamino-2-methylpentane with a cresyl glycidyl ether in a ratio of moles of the 1,5-diamino-2-methylpentane to moles of the cresyl glycidyl ether ranging from 1/0.9 to 1/1.2.

Assignees

• Sika Tech Ag

Inventors

• Kasemi Edis
• Kramer Andreas
• Stadelmann Ursula
• Burckhardt Urs

Classifications

• C08G59/56 Primary

  together with other curing agents · CPC title

• C08G59/184 Primary

  with amines · CPC title

• C09D163/00

  Coating compositions based on epoxy resins; Coating compositions based on derivatives of epoxy resins · CPC title

• C08G2650/50

  containing nitrogen, e.g. polyetheramines or Jeffamines(r) · CPC title

• C08G59/223

  together with monoepoxy compounds · CPC title