초록 ▼

A mixture of virgin crumb rubber sized to between 30 mesh and 100 mesh containing less than 5%+100 fines and thermoplastic binder, such as carbon black filled polyethylene containing a coating promoter, such as a citrate salt and lubricant, such as a calcium stearate, is mixed in a vented Banburg mi

A mixture of virgin crumb rubber sized to between 30 mesh and 100 mesh containing less than 5%+100 fines and thermoplastic binder, such as carbon black filled polyethylene containing a coating promoter, such as a citrate salt and lubricant, such as a calcium stearate, is mixed in a vented Banburg mixer heated to at least 350°F. to remove volatiles through vent before extrusion. The mixture is formed into sheet in the nip of a two roll assembly and cooled in air before diced into pellets by a dicer. The pellets are formed into porous pipe by extrusion in a pipe extruder having the feeding, transition and metering zones separately heated to temperatures from 320°F. to 400°F. (T1, T2, T3). The die has a separate jacket receiving heat exchange fluid for heating the die to a temperature from 290°F. to 380°F. to form a porous pipe having more uniformly spaced and sized pores and a smoother inner wall surface. The linearity factor, tensile strength and elongation are also improved.

대표청구항 ▼

A porous pipe comprising a hollow pipe having a pipe wall containing uniformly spaced pores, said pipe being formed of uniformly sized, vulcanized elastomer particles differing by no more than 5% from an average size dispersed in a thermoplastic resin, at least 90% of the particles exposed on the in

A porous pipe comprising a hollow pipe having a pipe wall containing uniformly spaced pores, said pipe being formed of uniformly sized, vulcanized elastomer particles differing by no more than 5% from an average size dispersed in a thermoplastic resin, at least 90% of the particles exposed on the inner wall of the pipe being coated with said binder resin.