Abstract The moldings are manufactured from synthetic thermoplastics, from non-thermoplastic fibrous flakes, which are available in an uncoated or incompletely coated state, and from optionally admixed fillers. The fibrous flakes and the thermoplastic material are mixed under the action of pressure and heat to produce a precompacted composite material, in which the fibrous flake material constitutes about 65% or more by volume of the composite material, and the latter is then extruded and is subsequently finally shaped and finally compacted at the same time. To manufacture the precompacted composite material, the non-thermoplastic materials consisting of the fibrous flake material and of any fillers, as well as synthetic thermoplastics which are adapted to adhere to the fibrous flake material, are subjected to a pretreatment, by which the thermoplastic and non-thermoplastic materials are extruded at elevated temperature and are thus bonded together and the extrusions are subsequently chopped to form a flowable composite particulate material.
A process of manufacturing a flowable composite particulate suitable for use in extrusion molding, comprising: (a) charging synthetic thermoplastic to an unheated extruder; (b) simultaneously charging and admixing a non-thermoplastic material to the extruder with the proviso that the non-thermoplastic material constitutes about 65% or more by volume of the total charged material; (c) extruding the mixture in the absence of external heat through the bores of a perforated die at a rate sufficient to generate frictional heat adequate to bond the thermoplastic and non-thermoplastic materials to one another as they pass through the die, but not before; and (d) severing the extrudate into a discrete flowable composite particulate; with the proviso that said flowable composite particulate has a bulk density of from 200 to 500 grams per liter.
Claim 2
Dependent Claim
129 words
A process of manufacturing a flowable composite particulate suitable for use in extrusion molding, comprising: (a) charging synthetic thermoplastic to an unheated extruder; (b) simultaneously charging and admixing a non-thermoplastic material to the extruder with the proviso that the non-thermoplastic material constitutes about 65% or more by volume of the total charged material; (c) extruding the mixture in the absence of external heat through the bores of a perforated die at a rate sufficient to generate frictional heat adequate to bond the thermoplastic and non-thermoplastic materials to one another as they pass through the die, but not before; and (d) severing the extrudate into a discrete flowable composite particulate; with the proviso that said flowable composite particulate has a bulk density of from 200 to 500 grams per liter.
Claim 3
Dependent Claim
40 words
The process of claim 1, wherein the non-thermoplastic material is selected from the group consisting of fibrous flakes having an area below 10 mm 2 and random fibrous material having a bulk density of at least 10 grams per liter.
Claim 4
Dependent Claim
29 words
The process of claim 1, wherein the discrete composite particles which partly adhere to each other are cooled in an air stream whereby they disintegrate into individual composite particles.
Claim 5
Dependent Claim
13 words
The process of claim 1, wherein the non-thermoplastic material further comprises a filler.
Claim 6
Dependent Claim
16 words
The process of claim 4, wherein the filler is admixed before the thermoplastic material is plasticized.