Method for producing porous shaped products

Claim 1

A method of producing a porous plastic molded product of predictable porosity throughout, comprising the steps of forming a fluidized stream of ultra-high-molecular-weight moldable-plastic powder solid particles and air; injecting said fluidized powder airstream into a cavity of a closed mold, composed of mating portions which define said cavity when mutually closed together and which confines said powder within its interior, to fill said mold cavity with said powder while said airstream leaves said cavity through means for escape of said air while precluding flow of said particles from said cavity; maintaining said mold at a temperature and for a time sufficient to fuse or sinter said powder particles together, in situ within said mold, without needing the imposition upon said powder of any molding pressure beyond that developed by said injecting in order to fuse or sinter said particles, without opening said portions apart and without melting said particles, thereby to form a porous plastic molded product of uniform predictable porosity and the exterior of which has a determined size and shape defined by and conformed to the shape and size of said interior; and subsequently discharging said porous plastic molded product from said mold without first having to have cooled said mold.

Claim 2

A method of producing a porous plastic molded product of predictable porosity throughout, comprising the steps of forming a fluidized stream of ultra-high-molecular-weight moldable-plastic powder solid particles and air; injecting said fluidized powder airstream into a cavity of a closed mold, composed of mating portions which define said cavity when mutually closed together and which confines said powder within its interior, to fill said mold cavity with said powder while said airstream leaves said cavity through means for escape of said air while precluding flow of said particles from said cavity; maintaining said mold at a temperature and for a time sufficient to fuse or sinter said powder particles together, in situ within said mold, without needing the imposition upon said powder of any molding pressure beyond that developed by said injecting in order to fuse or sinter said particles, without opening said portions apart and without melting said particles, thereby to form a porous plastic molded product of uniform predictable porosity and the exterior of which has a determined size and shape defined by and conformed to the shape and size of said interior; and subsequently discharging said porous plastic molded product from said mold without first having to have cooled said mold.

Claim 11

A method of producing a porous plastic molded product of predictable porosity throughout, comprising the steps of forming a fluidized stream of ultra-high-molecular-weight moldable-plastic powder solid particles and moisturized air; injecting said moisturized, fluidized powder airstream into a cavity of a closed mold, composed of mating portions which define said cavity when mutually closed together and which confines said powder within its interior, to fill said mold cavity with said powder while said airstream leaves said cavity through means for escape of said air while precluding flow of said particles from said cavity; maintaining said mold at a temperature and for a time sufficient to fuse or sinter said powder particles together, in situ within said mold, without needing the imposition upon said powder of any molding pressure beyond that developed by said injecting in order to fuse or sinter said particles, without opening said portions apart and without melting said particles, thereby to form a porous molded product and the exterior of which has a determined size and shape defined by and conformed to the shape and size of said interior, partially separating said mating portions of said mold and cooling said product sufficiently to increase its rigidity and without first having to have cooled said mold; and subsequently discharging said cooled porous plastic, molded product from said mold.

Claim 12

A method of producing a porous plastic molded product of predictable porosity throughout, comprising the steps of forming a fluidized stream of ultra-high-molecular-weight moldable-plastic powder solid particles and moisturized air; injecting said moisturized, fluidized powder airstream into a cavity of a closed mold, composed of mating portions which define said cavity when mutually closed together and which confines said powder within its interior, to fill said mold cavity with said powder while said airstream leaves said cavity through means for escape of said air while precluding flow of said particles from said cavity; maintaining said mold at a temperature and for a time sufficient to fuse or sinter said powder particles together, in situ within said mold, without needing the imposition upon said powder of any molding pressure beyond that developed by said injecting in order to fuse or sinter said particles, without opening said portions apart and without melting said particles, thereby to form a porous molded product and the exterior of which has a determined size and shape defined by and conformed to the shape and size of said interior, partially separating said mating portions of said mold and cooling said product sufficiently to increase its rigidity and without first having to have cooled said mold; and subsequently discharging said cooled porous plastic, molded product from said mold.

Claim 13

A method of producing a porous plastic molded product of predictable porosity throughout, comprising the steps of forming a fluidized stream of ultra-high-molecular-weight moldable-plastic powder solid particles and air; injecting said fluidized powder airstream into a cavity of a closed mold, composed of mating portions which define said cavity when mutually closed together and which confines said powder within its interior, to fill said mold cavity with said powder whle said airstream leaves said cavity through means for escape of said air while precluding flow of said particles from said cavity; maintaining said mold at a temperature and for a time sufficient to at least partially fuse or sinter said powder particles together, in situ within said mold, without needing the imposition upon said powder of any molding pressure beyond that developed by said injecting in order to fuse or sinter said particles, without opening said portions apart and without melting said particles, thereby to form a porous plastic molded product and the exterior of which has a determined size and shape defined by and conformed to the shape and size of said interior; subsequently discharging said porous plastic molded product from said mold without first having to have cooled said mold; and placing said molded product in an oven maintained at a temperature sufficient to complete rigidification of said molded product without melting said powder particles or glazing the surface of said molded product.

Claim 14

A method of producing a porous plastic molded product of predictable porosity throughout, comprising the steps of forming a fluidized stream of ultra-high-molecular-weight moldable-plastic powder solid particles and air; injecting said fluidized powder airstream into a cavity of a closed mold, composed of mating portions which define said cavity when mutually closed together and which confines said powder within its interior, to fill said mold cavity with said powder whle said airstream leaves said cavity through means for escape of said air while precluding flow of said particles from said cavity; maintaining said mold at a temperature and for a time sufficient to at least partially fuse or sinter said powder particles together, in situ within said mold, without needing the imposition upon said powder of any molding pressure beyond that developed by said injecting in order to fuse or sinter said particles, without opening said portions apart and without melting said particles, thereby to form a porous plastic molded product and the exterior of which has a determined size and shape defined by and conformed to the shape and size of said interior; subsequently discharging said porous plastic molded product from said mold without first having to have cooled said mold; and placing said molded product in an oven maintained at a temperature sufficient to complete rigidification of said molded product without melting said powder particles or glazing the surface of said molded product.

Claim 15

A method of producing a porous plastic molded product of predictable porosity throughout, comprising the steps of forming a fluidized stream of ultra-high-molecular-weight moldable-plastic powder solid particles and moisturized air, as a uniform fluidized dispersion of powder in said airstream; injecting said moisturized, fluidized, powder airstream into a cavity of a closed mold, composed of mating portions which define said cavity when mutually closed together and which confines said powder within its interior, to fill said mold cavity with said powder while said airstream leaves said cavity through means for escape of said air while precluding flow of said particles from said cavity; maintaining said mold at a temperature and for a time sufficient to at least partially fuse or sinter said powder particles together, in situ within said mold, without needing the imposition upon said powder of any molding pressure beyond that developed by said injecting in order to fuse or sinter said particles, without opening said portions apart and without melting said particles, thereby to form a porous plastic molded product and the exterior of which has a determined size and shape defined by and conformed to the shape and size of said interior; partially separating mating portions of said mold and cooling said product sufficiently to increase its rigidity and without first having to have cooled said mold; discharging said porous plastic molded product from said mold; and thereafter heating said molded product in an oven at a temperature and for a time sufficient to complete rigidification of said molded product without melting said plastic or glazing said product, thereby producing a porous plastic molded product of uniform, predictable porosity.

Claim 16

A method of producing a porous plastic molded product of predictable porosity throughout, comprising the steps of forming a fluidized stream of ultra-high-molecular-weight moldable-plastic powder solid particles and moisturized air, as a uniform fluidized dispersion of powder in said airstream; injecting said moisturized, fluidized, powder airstream into a cavity of a closed mold, composed of mating portions which define said cavity when mutually closed together and which confines said powder within its interior, to fill said mold cavity with said powder while said airstream leaves said cavity through means for escape of said air while precluding flow of said particles from said cavity; maintaining said mold at a temperature and for a time sufficient to at least partially fuse or sinter said powder particles together, in situ within said mold, without needing the imposition upon said powder of any molding pressure beyond that developed by said injecting in order to fuse or sinter said particles, without opening said portions apart and without melting said particles, thereby to form a porous plastic molded product and the exterior of which has a determined size and shape defined by and conformed to the shape and size of said interior; partially separating mating portions of said mold and cooling said product sufficiently to increase its rigidity and without first having to have cooled said mold; discharging said porous plastic molded product from said mold; and thereafter heating said molded product in an oven at a temperature and for a time sufficient to complete rigidification of said molded product without melting said plastic or glazing said product, thereby producing a porous plastic molded product of uniform, predictable porosity.

Claim 17

A method of producing a porous plastic molded product of predictable porosity throughout, comprising the steps of forming a fluidized stream of ultra-high-molecular-weight moldable ultra-high-molecular-weight polyethylene polymer solid particles having a particle size of from about 60 microns to about 180 microns and in a uniform dispersion of powder in said airstream; injecting said moisturized, fluidized, powder airstream into a cavity of a closed mold, composed of mating portions which define said cavity when mutually closed together and which confines said powder within its interior, to fill said cavity with said powder while said airstream leaves said cavity through means for escape of said air while precluding flow of said particles from said cavity; maintaining said mold at a temperature and for a time sufficient to at least partially fuse or sinter said powder particles together, in situ within said mold, without needing the imposition upon said powder of any molding pressure beyond that developed by said injecting in order to fuse or sinter said particles, without opening said portions apart and without melting said particles, thereby to form a porous, plastic molded product and the exterior of which has a determined size and shape defined by and conformed to the shape and size of said interior; partially separating said mating portions of said mold and cooling said product sufficiently to increase its rigidity; subsequently discharging said porous plastic molded product from said mold; and thereafter heating said molded product in an oven at a temperature and for a time sufficient to complete rigidification of said molded product without melting said plastic or glazing said product, thereby producing a porous plastic molded product of uniform predictable porosity.

Claim 18

A method of producing a porous plastic molded product of predictable porosity throughout, comprising the steps of forming a fluidized stream of ultra-high-molecular-weight moldable ultra-high-molecular-weight polyethylene polymer solid particles having a particle size of from about 60 microns to about 180 microns and in a uniform dispersion of powder in said airstream; injecting said moisturized, fluidized, powder airstream into a cavity of a closed mold, composed of mating portions which define said cavity when mutually closed together and which confines said powder within its interior, to fill said cavity with said powder while said airstream leaves said cavity through means for escape of said air while precluding flow of said particles from said cavity; maintaining said mold at a temperature and for a time sufficient to at least partially fuse or sinter said powder particles together, in situ within said mold, without needing the imposition upon said powder of any molding pressure beyond that developed by said injecting in order to fuse or sinter said particles, without opening said portions apart and without melting said particles, thereby to form a porous, plastic molded product and the exterior of which has a determined size and shape defined by and conformed to the shape and size of said interior; partially separating said mating portions of said mold and cooling said product sufficiently to increase its rigidity; subsequently discharging said porous plastic molded product from said mold; and thereafter heating said molded product in an oven at a temperature and for a time sufficient to complete rigidification of said molded product without melting said plastic or glazing said product, thereby producing a porous plastic molded product of uniform predictable porosity.

Claim 19

A method of producing a porous plastic molded product of predictable porosity throughout, comprising the steps of forming a fluidized stream of moldable plastic powder solid particles and air, said material having a melt flow index sufficiently low that it can be heated above its crystalline melting point without destroying porosity when cured; injecting said fluidized powder airstream into a cavity of a closed mold, composed of mating portions which define said cavity when mutually closed together and which confines said powder within its interior, to fill said mold cavity with said powder while said airstream leaves said cavity through means for escape of said air while precluding flow of said particles from said cavity; maintaining said mold at a temperature above said crystalline melting point and for a time sufficient to fuse or sinter said powder particles together, in situ within said mold, without needing the imposition upon said powder of any molding pressure beyond that developed by said injecting in order to fuse or sinter said particles, without opening said portions apart and without melting said particles, thereby to form a porous, plastic molded product of predictable porosity and the exterior of which has a determined size and shape defined by and conformed to the shape and size of said interior; and subsequently discharging said porous plastic molded product from said mold without first having to have cooled said mold.

Claim 20

A method of producing a porous plastic molded product of predictable porosity throughout, comprising the steps of forming a fluidized stream of moldable plastic powder solid particles and air, said material having a melt flow index sufficiently low that it can be heated above its crystalline melting point without destroying porosity when cured; injecting said fluidized powder airstream into a cavity of a closed mold, composed of mating portions which define said cavity when mutually closed together and which confines said powder within its interior, to fill said mold cavity with said powder while said airstream leaves said cavity through means for escape of said air while precluding flow of said particles from said cavity; maintaining said mold at a temperature above said crystalline melting point and for a time sufficient to fuse or sinter said powder particles together, in situ within said mold, without needing the imposition upon said powder of any molding pressure beyond that developed by said injecting in order to fuse or sinter said particles, without opening said portions apart and without melting said particles, thereby to form a porous, plastic molded product of predictable porosity and the exterior of which has a determined size and shape defined by and conformed to the shape and size of said interior; and subsequently discharging said porous plastic molded product from said mold without first having to have cooled said mold.