Epoxy systems having improved fracture toughness

Patent metadata

Field	Value
Publication number	US-10081704-B2
Application number	US-201615077071-A
Country	US
Kind code	B2
Filing date	Mar 22, 2016
Priority date	Mar 24, 2015
Publication date	Sep 25, 2018
Grant date	Sep 25, 2018

Abstract

The disclosure relates to at least one partially reacted product of an isocyanate and an amine (e.g., a reaction product comprising at least one adducted compound). The reaction product comprises polyurea oligomers. The reaction product can be combined with at least one amine in order to formulate a curing agent for epoxy resins wherein the cured epoxy resin has enhanced fracture toughness. The at least partially reacted product does not increase the viscosity of the curing agent and is at least partially soluble in the amine component of the curing agent.

First claim

The invention claimed is:

1. An epoxy curing agent comprising at least one liquid polyurea oligomer and at least one polyamine, wherein the oligomer comprises an adduct of an isocyanate and aromatic diamine selected from the group consisting of polytetramethyleneoxide-di-p-aminobenzoate, polytetraethyleneoxide-di-p-aminobenzoate, polytetrapropyleneoxide-di-p-aminobenzoate, and polytetrahexyleneoxide-di-p-aminobenzoate.

2. The curing agent of claim 1 wherein the range of isocyanate to aromatic diamine to form the polyurea oligomer is from 0.3:1 to 0.5:1.

3. The curing agent of claim 1 wherein the isocyanate comprises at least one cycloaliphatic diisocyanate.

4. The curing agent of claim 1 wherein the isocyanate comprises at least one member selected from the group consisting of methylenediphenyldiisocyanate (MDI), toluenediisocyanate (TDI), and isophoronediisocyanate (IPDI).

5. The curing agent of claim 1 wherein the polyurea oligomer is at least partially soluble in aliphatic amine.

6. The curing agent of claim 1 wherein the polyamine comprises at least one member selected from the group consisting of diethylenetriamine (DETA), triethylenetetramine (TETA), teraethylenepentamine (TEPA), pentaethylenehexamine (PEHA), hexamethylenediamine (HMDA), N-(2-aminoethyl)-1,3-propanediamine (N 3 -Amine), N, N′-1,2-ethanediyIbis-1,3-propanediamine (N 4 -amine), and dipropylenetriamine.

7. A method for producing the epoxy curing agent of claim 1 comprising contacting at least one isocyanate and an excess of at least one aromatic diamine to produce at least one liquid polyurea oligomer, and further contacting the at least one polyurea oligomer with at least one polyamine.

8. The curing agent of claim 2 wherein the range of isocyanate to aromatic diamine to form the polyurea oligomer is 0.3:1.

9. The curing agent of claim 2 wherein the range of isocyanate to aromatic diamine to form the polyurea oligomer is 0.5:1.

Assignees

• Evonik Degussa Gmbh

Inventors

• Patel Pritesh G
• Espinoza Perez Judith Dolores
• Lal Gauri Sankar
• Bender Jared Denis
• Tijsma Edze Jan

Classifications

• C08G59/4021 Primary

  Ureas; Thioureas; Guanidines; Dicyandiamides · CPC title

• C09J163/00

  Adhesives based on epoxy resins; Adhesives based on derivatives of epoxy resins · CPC title

• C08L75/02

  Polyureas · CPC title

• C08G59/245

  aromatic · CPC title

• C08L63/00

  Compositions of epoxy resins; Compositions of derivatives of epoxy resins · CPC title