Deformable pulp paper product, its method of manufacture and method of use
First Claim
1. A method of forming a deformable, molded fiber product comprising the steps of,vacuum accreting a preform from slurried fibers comprising a mixture of fibers and at least one thermoplastic resin normally hard and having a softening point less than the degradation point of the most flammable fiber in the slurry,pressing said preform in a mold assembly, said mold assembly having uniformly spaced parallel grooves in a surface which contacts the preform, to form a molded fiber product, the grooves in said mold assembly forming uniformly spaced ridges on at least one surface of said product, said ridges constituting areas of low density,and drying said product to form said deformable molded fiber product, said ridges being sufficient in number to permit deformation of said deformable product without destruction of said product.
3 Assignments
0 Petitions
Accused Products
Abstract
A deformable molded fiber product is formed by a method of felting, pressing and drying the compressed product having a uniformly spaced series of low density ridges on one surface. These ridges provide the molded fiber product with sufficient flexibility so that is may be subjected to a hot swaging like process to change its dimensions. A method of forming detents by hot pressing is also shown. The process is particularly useful in forming combustible nitrocellulose shell casings from a single pulp molding operation.
17 Citations
30 Claims
-
1. A method of forming a deformable, molded fiber product comprising the steps of,
vacuum accreting a preform from slurried fibers comprising a mixture of fibers and at least one thermoplastic resin normally hard and having a softening point less than the degradation point of the most flammable fiber in the slurry, pressing said preform in a mold assembly, said mold assembly having uniformly spaced parallel grooves in a surface which contacts the preform, to form a molded fiber product, the grooves in said mold assembly forming uniformly spaced ridges on at least one surface of said product, said ridges constituting areas of low density, and drying said product to form said deformable molded fiber product, said ridges being sufficient in number to permit deformation of said deformable product without destruction of said product.
-
15. A method in which a die dried pulp molding is swaged into shapes difficult to mold in rigid dies comprising the steps of:
-
vacuum accreting a preform from slurried fibers on which at least one thermoplastic resin, normally hard at temperatures to about 150 degrees Fahrenheit and having a softening point less than the degradation temperature of the most flammable fiber in the slurry, has been deposited; and drying the preform at 5 to 250 psi in heated rigid dies to create the molding, one of which carries uniformly spaced longitudinal grooves, and connected to vacuum to carry off steam and water, the said grooves producing protuberant parallel ridges in the molding which are of lower density than the more thoroughly pressed portions; heating the molding to soften the thermoplastic binder; and applying a swaging tool to the molding to swage the same by compressing the low density ridges together and allowing them to be densified, thus increasing the strength of the molding and reducing the dimensions of the molding at the swaged portion. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
-
-
29. A method of forming a combustible shell casing comprising the steps of:
-
vacuum accreting a preform from a slurry containing nitrocellulose and other fibers on which thermoplastic resins have been deposited, at least one of the resins being normally hard at temperatures to about 150 degrees Fahrenheit and having a softening point less than the degradation temperature of the nitrocellulose; pressing and drying the perform in dies shaped to form a molding open at least at one end and having uniformly spaced longitudinal ridges on the inner surface, said ridges being of reduced density formed at substantilly 10 degree centers and at less than 10 degree centers; bringing the portion of the molding to be deformed into a semiplastic condition and subsequently forcing this portion into a swaging die to produce a reduced dimension along a predetermined length of the molding; removing the deformed molding from the swaging die, and again, while the composition has been brought to a semiplastic state, subsequently forming at least one detent about the circumference of the reduced dimension; and fitting a metal stub base to the detent to close the open end of the molding to form said shell casing.
-
-
30. A method in which a die dried pulp molding is swaged into shapes difficult to mold in rigid dies comprising the steps of:
-
vacuum accreting a preform from slurried fibers on which thermoplastic resins have been deposited, drying the preform in heated mated rigid dies, one of which carries grooves connected to vacuum to carry off water and steam, the said grooves producing protuberant ridges in the molding which are of lower density than the more thoroughly pressed portions; heating the molding to soften the thermoplastic binder; and applying a swaging tool to the perform to swage the same by compressing the low density ridges together and allowing them to be densified, thus increasing the strength of the molding and reducing the dimensions of the molding at the swaged portion.
-
Specification