Aluminum phosphorus acid salts as epoxy resin cure inhibitors

Patent metadata

Field	Value
Publication number	US-9145488-B2
Application number	US-201213455414-A
Country	US
Kind code	B2
Filing date	Apr 25, 2012
Priority date	May 19, 2011
Publication date	Sep 29, 2015
Grant date	Sep 29, 2015

Abstract

Certain aluminum salts of organic phosphorus acids are found to have a strong effect on inhibiting the epoxy cure rate in epoxy formulations. The substances act catalytically and can be used at a low level in an epoxy formulation to adjust the reactivity of a resin formulation to give longer gel times. Compositions and methods of preparing and using the compositions are disclosed.

First claim

What is claimed:

1. A composition comprising
a) an epoxy resin,
b) a cross linker comprising a phenolic cross linker and wherein the composition comprises from about 50 to about 150% of the stoichiometric amount of hydroxy groups needed to cure the epoxy resin,
c) from 0.1 to 2 parts per hundred parts of epoxy resin of an aluminum phosphonate, phosphinate or phosphate salt cure inhibitor selected from compounds having the formula I:

wherein X and Y are independently selected from C 1-10 alkoxy, C 1-10 alkyl, C 6-10 aryl, C 6-10 aryl substituted by one or more C 1-10 alkyl, C 6-10 aryloxy and C 6-10 aryloxy substituted by one or more C 1-10 alkyl, and
d) a phosphorus containing flame retardant comprising from about 10 to 50 wt % of one or more compounds of formula (i)

from about 30 to 60 wt % of one or more compounds of formula (ii)

from about 10 to 50 wt % of one or more compounds of formula (iii)

and
from 0 to about 10 wt % tri-phenyl phosphine oxide based on the combined weight of compounds of formula (i), (ii), (iii) and tri-phenyl phosphine oxide,
wherein each R is independently hydrogen or an alkyl group containing from 1 to 6 carbon atoms, R 1 and R 2 are the same or different and each is an alkyl group containing from 1 to 6 carbon atoms, each of x and y is an integer from 0 through 4.

2. The composition according to claim 1 wherein each OR in the compounds of formulae (i), (ii) and (iii) are independently in the ortho- or para- position with respect to the bond between the P atom and the associated phenyl group.

3. The composition according to claim 2 wherein x and y are 0, R is hydrogen, and the ratio of the number of OR groups in the ortho-position with respect to the bond between the P atom and the associated phenyl group to the number of OR groups in the para-position with respect to the bond between the P atom and the associated phenyl group in the mixture is from about 20:80 to about 1:99.

4. The composition according to claim 3 wherein the ratio of the number of OR groups in the ortho-position with respect to the bond between the P atom and the associated phenyl group to the number of OR groups in the para-position with respect to the bond between the P atom and the associated phenyl group in the mixture is from about 10:90 to about 2:98.

5. The composition of claim 1 wherein the cure inhibitor c) is a aluminum phosphinate salt of formula I wherein X and Y are independently selected from C 1-10 alkyl, C 6-10 aryl and C 6-10 aryl substituted by one or more C 1-10 alkyl.

6. The composition of claim 1 wherein the epoxy resin a) comprises an epoxy novolac resin.

7. The composition of claim 1 wherein the cross linker b) comprises a novolac cross linker.

8. A process of slowing the cure rate of a curable epoxy composition by adding to an epoxy composition comprising an epoxy resin, a cross linker and a phosphorus containing flame retardant comprising from about 10 to 50 wt % of one or more compounds of formula (i)

from about 30 to 60 wt % of one or more compounds of formula (ii)

from about 10 to 50 wt % of one or more compounds of formula (iii)

and
from 0 to about 10 wt % tri-phenyl phosphine oxide based on the combined weight of compounds of formula (i), (ii), (iii) and tri-phenyl phosphine oxide,
wherein each R is independently hydrogen or an alkyl group containing from 1 to 6 carbon atoms R 1 and R 2 are the same or different and each is an alkyl group containing from 1 to 6 carbon atoms, each of x and y is an integer from 0 through 4,
from 0.1 to 2 parts per hundred parts of epoxy resin of an aluminum phosphonate, phosphinate or phosphate salt cure inhibitor selected from compounds having the structure I:

wherein X and Y are independently selected from C 1-10 alkoxy, C 1-10 alkyl, C 6-10 aryl, C 6-10 aryl substituted by one or more C 1-10 alkyl, C 6-10 aryloxy and C 6-10 aryloxy substituted by one or more C 1-10 alkyl.

9. A prepreg pepared by applying to, or impregnating into a substrate the composition according to claim 1 to obtain an epoxy coated substrate, heating the epoxy coated substrate at a temperature sufficient to draw off solvent from the epoxy formulation and optionally to partially cure the epoxy formulation to form the prepreg.

10. A laminate prepared by by stacking or layering sheets of prepreg according to claim 9 in alternating layers with one or more sheets of a conductive material, followed by processing to provide fully processed laminates.

11. The composition according to claim 1 further comprising e) an amine containing accelerant.

12. The process according to claim 9 wherein the curable epoxy composition further comprises an amine containing accelerant.

Assignees

• Timberlake Larry D
• Hanson Mark V
• Bol Kenneth
• Chemtura Corp

Inventors

• Timberlake Larry D
• Hanson Mark V
• Bol Kenneth

Classifications

• C08K5/13

  Phenols; Phenolates · CPC title

• B32B2307/202

  Conductive · CPC title

• B32B38/164

  Drying · CPC title

• C08K5/53 Primary

  bound to oxygen and to carbon only · CPC title

• B32B2363/00

  Epoxy resins · CPC title