# US 5,710,242 A · High temperature epoxy resins from hydrogenated quinoxalines

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- Number: US 5,710,242 A
- Document ID: US5710242A
- Status: Granted
- Kind: A
- Application number: 08/700,371
- Filed: 1996-10-25
- Granted: 1998-01-20
- Earliest claimed: 1994-02-24
- Assignees: The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland of Defence Evaluation and Research Agency
- Inventors: Peter Johncock; David Alan Jones
- Web page: https://patentgrep.com/patent/US5710242A

## CPC

- C07D 405/14: containing three or more hetero rings
- C08G 59/26: heterocyclic
- C08G 59/3245: {containing only nitrogen as a heteroatom}
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

A multi-functional epoxy resin with good high temperature properties allowing prolonged service at temperatures above 120.degree. C. is derived from a precursor of formula (I): ##STR1## in which R.sup.3 to R.sup.8 inclusive are independently selected from hydrogen, C.sub.1 to C.sub.3 alkyl or halo-alkyl and R.sup.9 is hydrogen, alkyl or halogen, and in which n has the value 0, 1 or 2. The precursor (I) may be self-coupled or cross-coupled with precursors of other epoxy compounds of the TGDDM type. Such cross-coupling gives rise to a complex mixture containing not only the mixed product, but also the self-coupled products of each constituent. Regardless of the precise chemical make-up of the mixture, the observed glass transition temperature is higher than for TGDDM resins formed without precursor (I). If the substituent at the R.sup.9 position is alkyl or halogen, oligomer formation is suppressed and a less complex mixture results.

## Claims

### Claim 1

A high temperature multi-functional epoxy resin precursor of formula (I): ##STR8## wherein R.sup.3 to R.sup.8 inclusive are independently selected from hydrogen, C.sub.1 to C.sub.3 alkyl or halo-alkyl, or aryl and wherein n=0,1 or 2, and wherein R.sup.9 =hydrogen, alkyl or halogen.

### Claim 2 (depends on 1)

An epoxy resin wherein the precursor as claimed in claim 1 (I) is substituted at the R.sup.9 position with hydrogen and self-coupled under acidic conditions in the presence of formaldehyde or benzaldehyde to give, after subsequent dehydrochlorination, a multi-functional compound of formula (II): ##STR9## and higher oligomers (III), wherein R.sup.1 to R.sup.8 inclusive are independently selected from H, C.sub.1 to C.sub.3 alkyl, halo-alkyl, or aryl, and wherein n=0, 1 or 2 and x=0 to 10. ##STR10##

### Claim 3 (depends on 2)

An epoxy resin as claimed in claim 2 wherein n=0 and R.sup.1 to R.sup.8 inclusive are hydrogen.

### Claim 4 (depends on 2)

An epoxy resin as claimed in claim 2 wherein n=1 and R.sup.1 to R.sup.8 inclusive are hydrogen.

### Claim 5 (depends on 2)

An epoxy resin as claimed in claim 2 wherein n=0, R.sup.1 =C.sub.6 H.sub.5 and R.sup.2 to R.sup.8 inclusive are hydrogen.

### Claim 6 (depends on 1)

An epoxy resin wherein the precursor as claimed in claim 1 (I) is substituted at the R.sup.9 position with alkyl or halogen and self-coupled in the presence of formaldehyde or benzaldehyde to give, after subsequent dehydrochlorination, a multi-functional compound of formula (IV): ##STR11## wherein R.sup.1 to R.sup.8 inclusive are independently selected from hydrogen, C.sub.1 to C.sub.3 alkyl or halo-alkyl, or aryl, and wherein n=0, 1 or 2.

### Claim 7 (depends on 6)

An epoxy resin as claimed in claim 6 wherein R.sup.1 to R.sup.8 are hydrogen and n=0.

### Claim 8 (depends on 1)

An epoxy resin wherein the precursor as claimed in claim 1 (I) in which R.sup.9 is hydrogen is cross-coupled with further precursor (I) in which R.sup.9 is alkyl or halogen.

### Claim 9 (depends on 8)

An epoxy resin as claimed in claim 8 wherein R.sup.3 to R.sup.8 are hydrogen, n=0 and R.sup.9 is hydrogen or CH.sub.3.

### Claim 10 (depends on 1)

An epoxy resin wherein the precursor as claimed in claim 1 is cross-coupled with a precursor (V) of the formula: ##STR12## in which X and Y are independently selected from halogen, haloalkyl or hydrogen, and at least one of the groups X or Y attached to each aromatic ring is a halogen or haloalkyl.

### Claim 11 (depends on 10)

An epoxy resin as claimed in claim 10 or wherein R.sup.3 to R.sup.8 inclusive are independently selected from hydrogen, C.sub.1 to C.sub.3 alkyl, halo-alkyl, or aryl, wherein n=0, 1 or 2 and wherein R.sup.9 is hydrogen.

### Claim 12 (depends on 11)

An epoxy resin as claimed in claim 11 wherein n=0 and R.sup.3 to R.sup.8 inclusive are hydrogen.

### Claim 13 (depends on 11)

An epoxy resin as claimed in claim 11 wherein n=1 and R.sup.3 to R.sup.8 inclusive are hydrogen.

### Claim 14 (depends on 6)

An epoxy resin as claimed in claim 6 wherein n=0, R.sup.1 =C.sub.6 H.sub.5 and R.sup.2 to R.sup.8 inclusive are hydrogen.

### Claim 15 (depends on 10)

An epoxy resin as claimed in claim 10 wherein n=0, R.sup.3 to R.sup.8 inclusive are hydrogen and R.sup.9 is alkyl or halogen.