Prepreg containing epoxy resin with improved flexural properties
View Patent ↗Prepreg that contains epoxy resin compositions that include an epoxy resin component and a curative powder comprising particles of 4,4′-diaminobenzanilide (DABA) wherein the size of the DABA particles is less than 100 microns and wherein the median particle size is below 20 microns.
1. A prepreg comprising:
a fibrous reinforcement; and
an uncured epoxy resin composition comprising:
an epoxy resin component; and
a curative powder comprising particles of 4,4′-diaminobenzanilide wherein the size of said particles is less than 100 microns and wherein the median particle size is below 20 microns.
2. A prepreg according to claim 1 wherein said the median particle size is between 10 microns and 20 microns.
3. A prepreg according to claim 1 wherein said epoxy resin component consists essentially of a trifunctional epoxy.
4. A prepreg according to claim 1 wherein the stoichiometric ratio of said epoxy component to said 4,4′-diamino benzanilide is between 1.0 to 1.0 and 1.0 to 0.7.
5. A prepreg according to claim 4 wherein the stoichiometric ratio of said epoxy component and said 4,4′-diamino benzanilide is about 1.0 to 0.85.
6. A prepreg according to claim 1 wherein at least 70 percent of the particles in said curative powder have a particle size of below 50 microns.
7. A cured laminate comprising prepreg according to claim 1 that has been cured.
8. A cured laminate comprising prepreg according to claim 2 that has been cured.
9. A cured laminate comprising prepreg according to claim 3 that has been cured.
10. A cured laminate comprising prepreg according to claim 4 that has been cured.
11. A cured laminate according to claim 7 which has a flexural strength of at least 25 ksi and a strain to failure of at least 4.0 percent.
12. A method for making a prepreg comprising the step of combining a fibrous reinforcement with an uncured epoxy resin composition comprising:
an epoxy resin component; and
a curative powder comprising particles of 4,4′-diaminobenzanilide wherein the size of said particles is less than 100 microns and wherein the median particle size is below 20 microns.
13. A method for making a prepreg according to claim 12 wherein said median particle size is between 10 microns and 20 microns.
14. A method for making a prepreg according to claim 12 wherein said epoxy resin component consists essentially of a trifunctional epoxy.
15. A method for making a prepreg according to claim 12 wherein the stoichiometric ratio of said epoxy component to said 4,4′-diamino benzanilide is between 1.0 to 1.0 and 1.0 to 0.7.
16. A method for making a prepreg according to claim 12 wherein at least 70 percent of the particles in said curative powder have a particle size of below 50 microns.
17. A method for making a cured laminate comprising the step of curing prepreg according to claim 1 .
18. A method for making a cured laminate comprising the step of curing prepreg according to claim 2 .
19. A method for making a cured laminate comprising the step of curing prepreg according to claim 3 .
20. A method for making a cured laminate comprising the step of curing prepreg according to claim 4 .