US 4,954,195 A · Production of thermoset composites containing thermoplastic fillers

Abstract

A process for increasing the damage tolerance in thermoset composites without loss of processibility or mechanical properties of the thermoset, by controlled solubility of a thermoplastic filler in the base thermoset. The process includes mixing spherical particles of a selected thermoplastic, such as polyimide, of particle size ranging from about 10 to 80 microns, with a hot thermoset resin, such as a bismaleimide, to form a uniform dispersion of the resin mixture, employing about 5 to about 40% of the thermoplastic by weight of the mixture of the two resins. The particles of thermoplastic are non-agglomerating and insoluble in the resin mixture. The hot resin dispersion is then applied to fiber reinforcement, such as carbon fiber tapes, to form pre-pregs. Upon curing the thermoset at elevated temperature, the thermoplastic particles dissolve in the thermoset resin, forming a composite with no definable boundary interfaces between the thermoplastic and thermosetting resins.

Claims14

Dependent claims

In a process for producing thermoset composites, the steps which comprise:

providing a suitable thermoplastic resin composition comprised of particles of a suitable thermoplastic resin having a particle size ranging from about 10 to about 80 microns,
providing a base thermosetting resin curable by heating, said thermoplastic resin being insoluble in said thermosetting resin at room temperature and at elevated processing temperatures prior to curing, but soluble in said thermosetting resin at cure conditions thereof, and
mixing said particles of thermoplastic resin and said thermosetting resin in liquid form in a proportion of about 5% to about 40% of said thermoplastic resin, by weight of said mixture, and forming a substantially uniform dispersion of said thermoplastic resin particles and said thermosetting resin, said particles of thermoplastic resin being substantially non-agglomerating in said thermosetting resin.

A process for producing a composite which is damage tolerant and thermally stable by controlled solubility of thermoplastic resin fillers in a thermosetting resin, which comprises:

dissolving a suitable thermoplastic resin in a suitable solvent,
recrystallizing and reforming said thermoplastic resin from said solvent, to form substantially spherical particles of said thermoplastic resin having a particle size ranging from about 10 to about 80 microns,
providing a base thermosetting resin in a liquid medium at elevated temperature, said thermosetting resin being curable by heating, said thermoplastic resin being insoluble in said thermosetting resin at room temperature and at processing temperatures ranging from about 140 to about 230.degree. F. but soluble in said thermosetting resin at increased temperature under cure conditions thereof,
incorporating said particles of thermoplastic resin into said liquid medium containing said thermosetting resin, while stirring the mixture, in a proportion of about 5% to about 40% of said thermoplastic resin, by weight of the mixture,
applying said mixture of thermoplastic resin and thermosetting resin to the surface of reinforcement fibers and forming a pre-preg, and
curing the thermosetting resin by heating at elevated temperature, said thermoplastic resin dissolving in said base thermosetting resin during curing.

3 more elements

Dependencies are inferred from the claim text.

Production of thermoset composites containing thermoplastic fillers

Life of this patent

Production of thermoset composites containing thermoplastic fillers

Life of this patent

Abstract

Claims14