IMPROVEMENTS IN OR RELATING TO CURING AGENTS

Abstract

A curative system comprising a combination of adipic acid dihydrazide and/or isophthalic dihydrazide and a clathrate in which the guest compound of the clathrate comprises an imidazole, an imidazoline or diazabicycloalkanes (DBCA).

Claims

1. A curative composition comprising a combination of adipic acid dihydrazide or isophthalic dihydrazide and a clathrate, said clathrate having a guest compound, said guest compound comprising an imidazole, an imidazoline or one or more diazabicycloalkanes (DBCA).

2. A The curative composition according to claim 1, wherein the clathrate contains a host component and a guest component, said guest component comprising at least one compound selected from the group consisting of a compound represented by formula: ##STR00004## in which R.sub.1 represents a hydrogen atom, a C.sub.1-C.sub.10 alkyl group, an aryl group, an arylalkyl group, or a cyanoethyl group, and R.sub.2 to R.sub.4 each independently represent a hydrogen atom, a nitro group, a halogen atom, a C.sub.1-C.sub.20 alkyl group, a C.sub.1-C.sub.20 alkyl group substituted with a hydroxy group, an aryl group, an arylalkyl group, or a C.sub.1-C.sub.20 acyl group; and a part with a dashed line represents a single bond or a double bond, and diazabicycloalkanes (DBCA) such as [1,8-diazabicyclo[5.4.0]undecene-7, 1,4-diazabicyclo[2.2.2]octane and 1,5-diazabicyclo[[4.3.0]non-5-ene.] and adipic acid dihydrazide or isophthalic acid dihydrazide.

3. The curative composition according to claim 2 in which the host component of the clathrate contains a single carboxylic acid group or carboxylic acid ester group.

4. The curative composition according to claim 3 in which the mol ratio of the host component to the guest component in the clathrate is in the range of from 0.95 to 1.1.

5. A The curative composition according to claim 4, further comprising a urea-based accelerator.

6. (canceled)

7. (canceled)

8. (canceled)

9. (canceled)

10. (canceled)

11. (canceled)

12. A moulding material comprising a thermosetting resin composition according to claim 5 in combination with a fibrous reinforcement material.

13. (canceled)

Description

EXAMPLES 1 TO 7

[0114] The following formulations with varying curative systems were prepared, each containing varying amounts of an imidazole in combination with ADH. All amounts for the components are in weight % (wt %) in relation to the total weight of the composition.

TABLE-US-00002 Example 1 2 3 4 5 6 7 Curative ADH/Urone ADH/Urone ADH BHPVA- ADH ADH BHPPA- ADH ADH system 2E4MZ 2E4MZ 2E4MZ PhPh-IMZ 2E4AMZ PhPh-IMZ PhPh-IMZ Novolac 45 45 37 29 37 24 36 (wt %) BPA-Type 20 20 16 16 16 16 16 1 (wt %) BADGE 18.5 18 29 29 29 29 29 (wt %) ADH (wt %) 9 9 7 7 7 7 7 Urone 7 7 (wt %) BHPVA- 11 2E4MZ (wt %) PhPh- 19 24 12 IMZ(wt %) BHPPA- 11 2E4MZ (wt %) 2E4MZ 0.5 1 (wt %) Outlife @ 1.5 3 6 6 6 6 6 23° C. (weeks) Time to 2.7 3.2 1.7 1.1 1.6 1 1.6 95% cure at 150° C. (min) Tg (° C.) 145 144 156 155 158 124 163 Active 0.5 1 3 3 3 4 2 amount of Imidazole (wt %)

[0115] The materials were stored at 23° C. and the time to onset of cure determined. The clathrate and adipic acid dihydrazide containing formulations were compared with formulations containing adipic acid, dihydrazide and a free imidazole. In every instance the time to onset of cure for the clathrate containing formulations (Examples 3 to 7) was about double the time for the free imidazole containing formulations (Examples 1 and 2).

[0116] The resin formulations were exposed to a temperature of 150° C. to isothermally cure the compositions and the time to peak exotherm and the time to reach 95% cure were measured. The time from the onset of cure to 95% cure when heated to 150° C. for the clathrate containing formulations (Examples 3 to 7) was less than half the time required for the free imidazoline containing formulations (Examples 1 and 2) whereas the Tg was in most instances at least 30% higher with the clathrate containing formulations.

EXAMPLES 8 TO 11

[0117] Basic formulations were prepared with a difunctional epoxy resin component and varying curative systems. The active amount of imidazole was varied in the different curative systems which each contain ADH. These formulations were again cured isothermally at 150° C.

TABLE-US-00003 Example 8 9 10 11 Curative system ADH/imidazole ADH/clathrate Urone/clathrate Urone/ (1% imidazole (3% imidazole (3% imidazole ADH content) content) content) Time to 4.6 2.6 1.8 5 95% cure at 150° C. (min) Tg (° C.) 135 145 157 148 Active 1.00 3.00 3.00 amount of Imidazole

[0118] The effect of a curative system was compared in relation to the time to cure at 150° C. and Tg for formulations of the same resin component in relation to curative systems containing

[0119] (i) Urone plus adipic acid dihydrazide

[0120] (ii) Adipic acid dihydrazide plus Imidazole

[0121] (iii) Adipic acid dihydrazide plus clathrate

[0122] (iv) Urone plus clathrate.

[0123] The formulation containing the adipic acid dihydrazide clathrate combination had the shortest time to reach 95% cure when heated to 150° C. and also had the highest cured Tg of 157° C.