초록 ▼

Relatively long plastic microfilaments are used to make reinforcing, filler materials and fabrics. A blowing gas is applied at a positive pressure to the inert surface of a liquid plastic film formed across a coaxial blowing nozzle to blow the film and form an elongated hollow tube having a thinned

Relatively long plastic microfilaments are used to make reinforcing, filler materials and fabrics. A blowing gas is applied at a positive pressure to the inert surface of a liquid plastic film formed across a coaxial blowing nozzle to blow the film and form an elongated hollow tube having a thinned wall or weakened portion. An entraining fluid is directed at an angle over and around the blowing nozzle and as it passes over and around the blowing nozzle, it dynamically induces a pulsating or fluctuating pressure field at the opposite side of the blowing nozzle in the wake thereof and produces a laminar flow of entraining fluid in the vicinity of the forming elongated tube. The continued movement of the entraining fluid over the elongated tube produces asymmetric fluid drag forces on the tube, and at the thinned wall or weakened wall portion longitudinally breaks the tube to form a multiplicity of plastic microfilaments, and detaches the plastic microfilaments from the elongated tube and from the coaxial blowing nozzle and the detached microfilaments are carried away from the blowing nozzle. Quench nozzles or heating nozzles may be disposed below and on either side of the blowing nozzle to direct cooling or heating fluid at and into contact with the plastic microfilaments to cool or heat and cure, solidify and harden the plastic to form hard, smooth plastic microfilaments.

대표청구항 ▼

1. A method for making microfilaments from an organic film forming material which comprises forming a liquid film of said organic material across an orifice, applying a blowing gas at a positive pressure on the inner surface of the liquid organic film to blow the film and form an elongated hollow or

1. A method for making microfilaments from an organic film forming material which comprises forming a liquid film of said organic material across an orifice, applying a blowing gas at a positive pressure on the inner surface of the liquid organic film to blow the film and form an elongated hollow organic material tube or cylinder, forming a thinned wall or weakened portion of the elongated hollow tube or cylinder, subjecting the elongated hollow tube or cylinder during its formation to an external pulsating or fluctuating pressure field having periodic osciallations, said pulsating or fluctuating pressure field acting on said elongated hollow tube or cylinder to assist in its formation and to assist in the formation of a multiplicity of organic material microfilaments and in detaching the organic material microfilaments from said orifice. 2. The method of claim 1 wherein the liquid film of organic film forming material is formed across the orifice of a coaxial blowing nozzle, said blowing nozzle having an inner nozzle to convey said blowing gas to the inner surface of the liquid organic material film, and an outer nozzle to convey said organic material to said orifice and means disposed near said orifice forming the thinned wall or weakened portion of said elongated hollow organic material tube or cylinder, and pulsating or fluctuating pressure inducing means is directed at an angle to said coaxial blowing nozzle to induce said pulsating or fluctuating pressure field at the opposite or lee side of said coaxial blowing nozzle in the wake or shadow of said coaxial blowing nozzle. 3. The method of claim 1 wherein an entraining fluid is directed at an angle to a coaxial blowing nozzle having an orifice, an inner nozzle and an outer nozzle, the liquid film of organic film forming material is formed across the orifice, the blowing gas is conveyed to the inner surface of the liquid organic film through said inner nozzle, the film forming organic material is conveyed through said outer nozzle to said orifice, and means disposed near said orifice between the inner and outer nozzle form a thinned wall or weakened portion of said elongated hollow organic material tube or cylinder and the entraining fluid passes over and around said coaxial nozzle to fluid dynamically induce the 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. 4. The method of claim 3 wherein the lower portion of the outer nozzle is tapered inwardly to form with the outer edge of the inner nozzle a fine gap and the film forming organic material is fed under pressure and extruded through said gap to form a thin film of film forming organic material across the orifice of the blowing nozzle. 5. A method for making plastic microfilaments from a plastic film forming material, which comprises forming a liquid plastic film across an orifice, applying a blowing gas at a positive pressure on the inner surface of the liquid plastic film to blow the film and form an elongated hollow plastic tube or cylinder, forming a thinned wall or weakened portion of the elongated hollow tube or cylinder, subjecting the elongated hollow tube or cylinder during its formation to a pulsating or fluctuating pressure field having periodic oscillations, said pulsating or fluctuating pressure field acting on said elongated hollow tube or cylinder to assist in its formation and to assist in the formation of a multiplicity of plastic microfilaments and in detaching the plastic microfilaments from said orifice. 6. The method of claim 5 wherein the liquid plastic film is formed across the orifice of a coaxial blowing nozzle, said blowing nozzle having an inner nozzle to convey said blowing gas to the inner surface of the liquid plastic film, and an outer nozzle to convey said liquid plastic to said orifice and means disposed near said orifice between the inner and outer nozzle form a thinned wall or weakened portion of said elongated hollow tube or cylinder, and pulsating or fluctuating pressure inducing means is directed at an angle to said coaxial blowing nozzle to induce said pulsating or fluctuating pressure field at the opposite or lee side of said coaxial blowing nozzle in the wake or shadow of said coaxial blowing nozzle. 7. The method of claim 6 wherein the liquid plastic has a viscosity of 0.10 to 600 poises. 8. The method of claim 6 wherein the liquid plastic has a viscosity of 10 to 350 poises. 9. The method of claim 6 wherein the liquid plastic has a viscosity of 30 to 200 poises. 10. The method of claim 3 wherein said entraining fluid has a linear velocity in the region of the elongated hollow tube or cylinder formation of 1 to 120 ft/sec and entrains and transports the microfilaments away from the blowing nozzle. 11. The method of claim 10 wherein said entraining fluid has a linear velocity in the region of elongated hollow tube or cylinder formation of 5 to 80 ft/sec. 12. The method of claim 10 wherein said entraining fluid has a linear velocity in the region of elongated hollow tube or cylinder formation of 10 to 60 ft/sec. 13. The method of claim 6 wherein the plastic microfilaments are one to 8 inches in length and have a diameter of 1.0 to 30 microns. 14. The method of claim 6 wherein the plastic microfilaments are 2 to 6 inches in length and 2.0 to 10 microns in diameter. 15. A method for making plastic microfilaments which comprises forming liquid plastic, forming a liquid plastic film 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 liquid plastic to said orifice, applying said blowing gas through said inner nozzle at positive pressure on the inner surface of the liquid plastic film to blow the film downwardly and outwardly to form an elongated hollow plastic tube or cylinder, means disposed near said orifice between the inner and outer nozzle form a thinned wall or weakened portion of said elongated hollow tube or cylinder, continuously feeding said liquid plastic to said outer nozzle while said elongated hollow tube or cylinder 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 elongated hollow plastic tube or cylinder to break up said tube or cylinder into a multiplicity of plastic microfilaments which are connected to said tube or cylinder at a point proximate to the coaxial blowing nozzle and said entraining fluid acting to detach the plastic microfilaments from the coaxial blowing nozzle and solidifying said plastic microfilaments. 16. The method of claim 15 wherein the lower portion of the outer nozzle is tapered inwardly to form with the outer edge of the orifice of the inner nozzle a fine gap and feeding the liquid plastic under pressure through said gap to form a thin film of liquid plastic across the orifice of the blowing nozzle. 17. The method of claim 16 wherein the plastic microfilaments are one to 8 inches in length and have a diameter of 1.0 to 30 microns. 18. The method of claim 16 wherein the plastic microfilaments are 2 to 6 inches in length and 2.0 to 10 microns in diameter.