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US 4,303,603 AGranted
Method and apparatus for producing hollow plastic microspheres
OwnerLeonard B. Torobininventor
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OwnerLeonard B. Torobininventor
Estimating the term…
Hollow plastic microspheres made from thermoplastic or thermosetting plastic compositions are described. The hollow plastic microspheres are made by forming a liquid film of thermoplastic or thermosetting plastic composition across a coaxial blowing nozzle, applying a blowing gas at a positive pressure to the inner surface of the plastic film to blow the film and form an elongated cylinder shaped liquid film of plastic. A transverse jet is used to direct an entraining fluid over and around the blowing nozzle at an angle to the axis of the blowing nozzle. The entraining fluid as it passes over and around the blowing nozzle fluid dynamically induces a pulsating or fluctuating pressure field at the opposite or lee side of the blowing nozzle in the wake or shadow of the coaxial blowing nozzle. The continued movement of the entraining fluid over the elongated cylinder produces asymmetric fluid drag forces on the cylinder and closes and detaches the elongated cylinder from the coaxial blowing nozzle and the detached cylinder by the action of surface tension forms into a spherical shape. Quench nozzles where the plastic is thermoplastic and heating nozzles where the plastic is thermosetting are disposed below and on either side of the blowing nozzle and direct cooling fluid or heating fluid at and into contact with the plastic microspheres to rapidly cool or heat and cure, solidify and harden the plastic to form hard, smooth hollow plastic microspheres. The hollow plastic microspheres can be used as filler materials in plastics, in plastic foam compositions and in concrete and asphalt compositions. The hollow plastic microspheres can be made from low heat conductivity plastic compositions and blown with a low heat conductivity gas and used to make improved insulation materials and composites and insulating systems. The hollow plastic microspheres can be made to contain a thin transparent or reflective metal coating deposited on the inner wall surface of the microspheres by adding to the blowing gas small dispersed metal particles and/or gases or organo metal compounds and decomposing the organo metal compounds. The hollow plastic microspheres can also be made in the form of filamented plastic microspheres with a thin plastic filament connecting adjacent plastic microspheres.
A method for making hollow microspheres from an organic film forming material which comprises forming a liquid film of said material across an orifice, applying a blowing gas at a positive pressure on the inner surface of the liquid film to blow the film and form the microsphere, subjecting the microsphere during its formation to an external pulsating or fluctuating pressure field having periodic oscillations, said pulsating or fluctuating pressure field acting on said microsphere to assist in its formation and to assist in detaching the microsphere from said orifice.
A method for making filamented, hollow plastic microspheres which comprises forming a liquid film of plastic across an orifice of a coaxial blowing nozzle, said blowing nozzle having an inner nozzle to convey blowing gas to the inner surface of the liquid film and an outer nozzle to convey plastic to said orifice, the lower portion of said outer nozzle being tapered inwardly to form with the outer edge of the inner nozzle a fine gap, feeding the plastic under pressure through said gap and forming said thin film of plastic across said orifice of the blowing nozzle, applying said blowing gas through said inner nozzle at positive pressure on the inner surface of the liquid film to blow the film downwardly and outwardly to form the microsphere, continuously feeding said plastic to said outer nozzle while said microsphere is being formed, directing an entraining fluid at said coaxial blowing nozzle, at a linear velocity in the region of microsphere formation of about 1 to 50 feet per second to obtain connecting plastic filaments between microspheres, and at an angle relative to a line drawn through the center axis of said coaxial blowing nozzle, said entraining fluid passing over and around said coaxial blowing nozzle to fluid dynamically induce a pulsating or fluctuating pressure field having periodic oscillations at the opposite or lee side of the blowing nozzle in the wake or shadow of said blowing nozzle, said entraining fluid acting on the microsphere to pinch and close off the microsphere at a point proximate to the coaxial blowing nozzle and said entraining fluid acting to detach the microsphere from the coaxial blowing nozzle, surface tension forces causing the detached microsphere to form a spherical shape, and cooling, solidifying and hardening said microsphere to obtain microspheres of 500 to 6,000 microns diameter and 0.5 to 400 microns wall thickness, said microspheres being connected by thin filamented portions that are continuous with the plastic microspheres.
A method for making hollow plastic microspheres which comprises forming a liquid film of plastic across an orifice, applying a blowing gas at a positive pressure on the inner surface of the liquid film to blow the film and form a microsphere, subjecting the microsphere during its formation to a pulsating or fluctuating pressure field having periodic oscillations, said pulsating or fluctuating pressure field acting on said microsphere to assist in its formation and to assist in detaching the microspheres from said orifice.
A method for making hollow plastic microspheres which comprises forming a liquid film of plastic across an orifice of a coaxial blowing nozzle, said blowing nozzle having an inner nozzle to convey an inert gas or organo metal compound blowing gas to the inner surface of the liquid film and an outer nozzle to convey said plastic to said orifice, applying said inert gas or organo metal compound blowing gas through said inner nozzle at positive pressure on the inner surface of the liquid film to blow the film downwardly and outwardly to form an elongated cylinder shaped liquid film of plastic which is closed at its outer end and connected at its inner end to the outer edge of the orifice of said blowing nozzle, continuously feeding said plastic to said nozzle while said elongated cylinder is being formed, directing an entraining fluid at said coaxial blowing nozzle at an angle of 25.degree. to 75.degree. relative to a line drawn through the center axis of said coaxial blowing nozzle, said entraining fluid passing over and around said coaxial blowing nozzle to fluid dynamically induce a pulsating or fluctuating pressure field having periodic oscillations at the opposite or lee side of the blowing nozzle in the wake or shadow of said blowing nozzle, whereby said entraining fluid envelops and acts on the elongated cylinder to flap, fold, pinch and close-off said elongated cylinder at its inner end at a point proximate to the coaxial blowing nozzle and said entraining fluid acting through drag forces on said cylinder to detach the cylinder from the coaxial blowing nozzle whereby surface tension forces cause the cylinder to form a spherical shape microsphere and directing a quench fluid into contact with said microsphere to rapidly cool and solidify said microsphere.
An apparatus for blowing hollow organic film forming material microspheres comprising a coaxial blowing nozzle consisting of an inner nozzle having an inner orifice at the lower end thereof for a blowing gas and an outer nozzle having an outer orifice for said material, said inner nozzle orifice being disposed proximate to said outer orifice, there being disposed external to said blowing nozzle means cooperating with said blowing nozzle by which there is induced a pulsating or fluctuating pressure field having periodic oscillations at the opposite or lee side of the blowing nozzle in the wake or shadow of said blowing nozzle.
An apparatus for blowing hollow plastic microspheres comprising a coaxial blowing nozzle consisting of an inner nozzle having an inner orifice at the lower end thereof for a blowing gas and an outer nozzle having an outer orifice for liquid plastic, said inner nozzle orifice being disposed proximate to said outer orifice, there being disposed external to said blowing nozzle a transverse jet cooperating with said blowing nozzle by which an entraining fluid is directed at said coaxial blowing nozzle at an angle of 25.degree. to 75.degree. relative to a line drawn through the center axis of said coaxial blowing nozzle such that said entraining fluid dynamically induces a pulsating or fluctuating pressure field having periodic oscillations at the opposite or lee side of the blowing nozzle in the wake or shadow of said blowing nozzle.
A method for making hollow plastic microspheres which comprises forming a liquid film of plastic across an orifice of a coaxial blowing nozzle, said blowing nozzle having an inner nozzle to convey a blowing gas to the inner surface of the liquid film and an outer nozzle to convey said plastic to said orifice, applying said blowing gas through said inner nozzle at positive pressure on the inner surface of the liquid film to blow the film downwardly and outwardly to form the microsphere, continuously feeding said plastic to said outer nozzle while said microsphere is being formed, directing an entraining fluid at said coaxial blowing nozzle at an angle relative to a line drawn through the center axis of said coaxial blowing nozzle, said entraining fluid passing over and around said coaxial blowing nozzle to fluid dynamically induce a pulsating or fluctuating pressure field having periodic oscillations at the opposite or lee side of the blowing nozzle in the wake or shadow of said blowing nozzle, said entraining fluid acting on the microsphere to pinch and close-off the microsphere at a point proximate to the coaxial blowing nozzle and said entraining fluid acting to detach the microsphere from the coaxial blowing nozzle, surface tension forces causing the detached microsphere to form a spherical shape, and cooling and solidifying said microsphere.
An apparatus for blowing hollow organic film forming material microspheres comprising a coaxial blowing nozzle comprising an inner nozzle having an inner orifice at the lower end thereof for a blowing gas and an outer nozzle having an outer orifice for said liquid material, said inner nozzle orifice being disposed proximate to said outer orifice, there being disposed external to said blowing nozzle means cooperating with said blowing nozzle by which there is induced a pulsating or fluctuating pressure field having periodic oscillations at the opposite or lee side of the blowing nozzle in the wake or shadow of said blowing nozzle.
An apparatus for blowing hollow plastic microspheres comprising a coaxial blowing nozzle comprising an inner nozzle having an inner orifice at the lower end thereof for a blowing gas and an outer nozzle having an outer orifice for the plastic, said inner nozzle orifice being disposed proximate to said outer orifice, there being disposed external to said blowing nozzle a transverse jet cooperating with said blowing nozzle by which an entraining fluid is directed at said coaxial blowing nozzle at an angle relative to a line drawn through the center axis of said coaxial blowing nozzle such that said entraining fluid dynamically induces a pulsating or fluctuating pressure field having periodic oscillations at the opposite or lee side of the blowing nozzle in the wake or shadow of said blowing nozzle.
A method for making hollow plastic microspheres which comprises forming a liquid film of plastic across an orifice of a coaxial blowing nozzle, said blowing nozzle having an inner nozzle to convey blowing gas to the inner surface of the liquid film and an outer nozzle to convey plastic to said orifice, the lower portion of said outer nozzle being tapered inwardly to form with the outer edge of the inner nozzle a fine gap, feeding the plastic under pressure through said gap and forming said thin film of plastic across said orifice of the blowing nozzle, applying said blowing gas through said inner nozzle at positive pressure on the inner surface of the liquid film to blow the film downwardly and outwardly to form the microsphere, continuously feeding said plastic to said outer nozzle while said microsphere is being formed, directing an entraining fluid at said coaxial blowing nozzle at an angle relative to a line drawn through the center axis of said coaxial blowing nozzle, said entraining fluid passing over and around said coaxial blowing nozzle to fluid dynamically induce a pulsating or fluctuating pressure field having periodic oscillations at the opposite or lee side of the blowing nozzle in the wake or shadow of said blowing nozzle, said entraining fluid acting on the microsphere to pinch and close-off the microsphere at a point proximate to the coaxial blowing nozzle and said entraining fluid acting to detach the microsphere from the coaxial blowing nozzle, surface tension forces causing the detached microsphere to form a spherical shape, and cooling, solidifying and hardening said microsphere to obtain microspheres of 500 to 6,000 microns diameter and 0.5 to 400 microns wall thickness.
Dependencies are inferred from the claim text.