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US 4,016,022 AGranted
Low flow, vacuum bag curable prepreg material for high performance composite systems
AssigneeThe United States of America as represented by the Secretary of the Air Force
InventorsCharles E. Browning, Theodore J. Reinhart, Jr.
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Abstract
A composite prepreg material comprising a carboxy-terminated polybutadiene, an epoxy novolak resin, a carboxylic acid accelerator and an epoxy catalyst. When reinforced with well known reinforcing fibers or filaments, the material is eminently suitable for use in the fabrication of structural composites.
Claims13
A method for fabricating a composite panel which comprises the following steps:
- a. mixing in a common solvent 100 parts by weight of a carboxy terminated vinyl polybutadiene and 100 to 150 parts by weight of an epoxy novolak resin with 2.5 to 2.6 parts by weight of chromium octoate;
- b. refluxing the resulting solution for a period of about 0.25 to 3 hours;
- c. at the end of the reflux period, cooling the solution to room temperature;
- d. adding to the cooled solution 8 to 10 parts by weight of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane and 1 to 5 parts by weight of benzyldimethylamine;
- e. stirring the solution containing the added materials, thereby obtaining a resin solution;
- f. coating the resin solution on a tape formed of reinforcing fibers;
- g. evaporating solvent from the resin solution, thereby obtaining tape impregnated with the resin;
- h. cutting the resin impregnated tape into plies of a desired size;
- i. stacking the plies to a desired thickness;
- j. placing a porous glass reinforced Teflon coated fabric on the top and bottom of the stack of plies;
- k. laying a breather cloth above and below the Teflon coated fabric;
- l. positioning the resulting assembly on a base plate and installing a vacuum bag thereover sealed to the base plate;
- m. evacuating air from the bag down to about 28 to 30 inches of mercury;
- n. placing the assembly in an air circulating oven;
- o. raising the temperature in the oven from room temperature to about 325.degree. to 375.degree. F at a rate of 3.degree. to 7.degree. F per minute;
- and
- p. maintaining the assembly at a temperature in the aforementioned range for a period of 0.75 to 1.5 hours, thereby obtaining a cured composite panel, the amount of resin in the panel being substantially equal to the amount of resin in the stacked plies.
14 more elements
A prepreg material consisting essentially of the following components:
- a. the reaction product obtained by reaction 100 parts by weight of a carboxy terminated vinyl polybutadiene and 100 to 150 parts by weight of an epoxy novolak resin in the presence of 2.5 to 2.6 parts by weight of chromium octoate;
- b. zero to 20 parts by weight of bis(4-maleimidophenyl)methane;
- c. 8 to 10 parts by weight of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane;
- and
- d. 1 to 5 parts by weight of epoxy catalyst.
2 more elements
A method for preparing a prepreg material which comprises the following steps:
- a. mixing in a common solvent 100 parts by weight of a carboxy terminated vinyl polybutadiene and 100 to 150 parts by weight of an epoxy novolak resin with 2.5 to 2.6 parts by weight of chromium octoate;
- b. refluxing the resulting solution for a period of about 0.25 to 3 hours;
- c. at the end of the reflux period, cooling the solution to room temperature;
- d. adding to the cooled solution 8 to 10 parts by weight of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane and 1 to 5 parts by weight of benzyldimethylamine;
- and
- e. stirring the solution containing the added materials, thereby obtaining a homogeneous solution of a prepreg material consisting essentially of a high vinyl polybutadiene endcapped with epoxy novolak resin, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane and benzyldimethylamine.
3 more elements
Dependencies are inferred from the claim text.