Method for fabricating improved fiber reinforced plastic rods having a smooth surface

Claim 1

The method of fabricating a solidified bundle of fiber reinforced plastic comprising the steps of wetting a plurality of strand-like fibers with a liquid heat-hardenable plastic, collecting said fibers into a plastic wetted bundle and unidirectionally intermittently pulling said bundle through a continuous elongated tubular die device, said die device being filled with said bundle, subjecting a length portion of said bundle in said die device to a predetermined pre-heating temperature for a given period of time which temperature and time conjointly are insufficient to solidify said plastic but which are conducive to solidification, pulling said length portion in which said plastic has not solidified to a successive portion in said die device for a distance substantially equal to the length of said length portion and then stopping, said plastic which has not solidified during such pre-heating to said predetermined temperature being sufficiently liquid as not to solidify during bundle movement, then subjecting that portion of the length of said length portion in which the plastic has not solidified to further enhanced heating at a higher predetermined temperature for another given period of time sufficient to solidify said plastic, solidification occurring during said enhanced heating at said higher predetermined temperature and while said bundle is stationary, said bundle remaining substantially in contact with said die device while residing therein except for shrinkage of the plastic and said die being unoperable.

Claim 2

The method of fabricating a solidified bundle of fiber reinforced plastic comprising the steps of wetting a plurality of strand-like fibers with a liquid heat-hardenable plastic, collecting said fibers into a plastic wetted bundle and unidirectionally intermittently pulling said bundle through a continuous elongated tubular die device, said die device being filled with said bundle, subjecting a length portion of said bundle in said die device to a predetermined pre-heating temperature for a given period of time which temperature and time conjointly are insufficient to solidify said plastic but which are conducive to solidification, pulling said length portion in which said plastic has not solidified to a successive portion in said die device for a distance substantially equal to the length of said length portion and then stopping, said plastic which has not solidified during such pre-heating to said predetermined temperature being sufficiently liquid as not to solidify during bundle movement, then subjecting that portion of the length of said length portion in which the plastic has not solidified to further enhanced heating at a higher predetermined temperature for another given period of time sufficient to solidify said plastic, solidification occurring during said enhanced heating at said higher predetermined temperature and while said bundle is stationary, said bundle remaining substantially in contact with said die device while residing therein except for shrinkage of the plastic and said die being unoperable.

Claim 4

The method of fabricating a solidified bundle of fiber reinforced plastic comprising the steps of wetting a plurality of strand-like fibers with a liquid heat-hardenable plastic, collecting said fibers into a plastic wetted bundle and unidirectionally intermittently pulling said bundle through a continuous elongated tubular die device, said die device being filled with and directly engaged by said bundle, heating said die device to different temperatures in discrete sequential zones, respectively, with the zones in the downstream direction being of increasing temperatures, said zones being of predetermined lengths, interrupting the pulling of said bundle after a predetermined length increment of said bundle has passed from said die device for a predetermined dwell time whereby said bundle is alternately at rest and moving a distance of said predetermined length, at least a portion of said length increment being moved from one of said zones to the next succeeding downstream zone during movement of said bundle for said predetermined length, the length of said predetermined length increment, the temperatures of the respective zones and said dwell time being such that said plastic in the moved predetermined length increment is pre-heated but does not fully solidify in the first upstream zone but does solidify in a successive zone such that the plastic is sufficiently liquid that it will not solidify during bundle movement, solidification occurring while the bundle is stationary, and further the plastic in the bundle which emerges from the die device being fully solidified, the surface of the emerging bundle is of a smoothness corresponding to the smoothness of the die device, the size and shape of the emerging bundle is substantially the same as the size and shape of the die device except for shrinkage of the plastic occurring as a result of solidification, said plastic shrinking during solidification thereby reducing the bundle size and the force required to pull said bundle through said die device, said bundle remaining substantially in contact with the die device while the bundle resides therein except for shrinkage of the plastic and said die being unoperable.

Claim 5

The method of fabricating a solidified bundle of fiber reinforced plastic comprising the steps of wetting a plurality of strand-like fibers with a liquid heat-hardenable plastic, collecting said fibers into a plastic wetted bundle and unidirectionally intermittently pulling said bundle through a continuous elongated tubular die device, said die device being filled with and directly engaged by said bundle, heating said die device to different temperatures in discrete sequential zones, respectively, with the zones in the downstream direction being of increasing temperatures, said zones being of predetermined lengths, interrupting the pulling of said bundle after a predetermined length increment of said bundle has passed from said die device for a predetermined dwell time whereby said bundle is alternately at rest and moving a distance of said predetermined length, at least a portion of said length increment being moved from one of said zones to the next succeeding downstream zone during movement of said bundle for said predetermined length, the length of said predetermined length increment, the temperatures of the respective zones and said dwell time being such that said plastic in the moved predetermined length increment is pre-heated but does not fully solidify in the first upstream zone but does solidify in a successive zone such that the plastic is sufficiently liquid that it will not solidify during bundle movement, solidification occurring while the bundle is stationary, and further the plastic in the bundle which emerges from the die device being fully solidified, the surface of the emerging bundle is of a smoothness corresponding to the smoothness of the die device, the size and shape of the emerging bundle is substantially the same as the size and shape of the die device except for shrinkage of the plastic occurring as a result of solidification, said plastic shrinking during solidification thereby reducing the bundle size and the force required to pull said bundle through said die device, said bundle remaining substantially in contact with the die device while the bundle resides therein except for shrinkage of the plastic and said die being unoperable.