Thermoplastic compositions, methods, apparatus, and uses

Abstract

Thermoplastic polyurethane (TPU) compositions, methods for producing TPU compositions, methods of using TPU compositions, and apparatuses produced therefrom are disclosed. Disclosed TPU compositions include a thermoplastic polyurethane polymer, a heat stabilizer, a flow agent, and a filler material. The filler may be a glass fiber. Disclosed TPU compositions have improved thermal stability and improved flow properties suitable for injection molding of articles of manufacture having a large plurality of fine openings or pores. Articles produced from the composition have superior thermal stability, abrasion resistance, and chemical resistance. Example articles include screening members for vibratory screening machines.

What is claimed is: 
     
         1 . A screen apparatus, comprising
 a screening element including a composition that includes a thermoplastic polyurethane configured to melt at a temperature in a range of about 148° C. to about 260° C.;   wherein the screening element is a single injection molded piece including openings generated during injection molding of the single injection molded piece, the openings have a size that is in a range from approximately 35 μm to approximately 4000 μm, and the screening element has an open screening area of approximately 10% or more of a total screening area.   
     
     
         2 . The screen apparatus of  claim 1 , further comprising one or more additional screening elements in combination with the screening element, wherein each of the one or more additional screening elements is an additional single injection molded piece including additional openings generated during injection molding of the additional single injection molded piece, the additional openings have the size that is in a range from approximately 35 μm to approximately 4000 μm, and each of the one or more additional screening elements has the open screening area of approximately 10% or more. 
     
     
         3 . The screen apparatus of  claim 1 , wherein the open screening area is 17% or more of the total screening area. 
     
     
         4 . The screen apparatus of  claim 1 , wherein the open screening area is from approximately 10% to approximately 35% of the total screening area. 
     
     
         5 . The screen apparatus of  claim 4 , wherein the open screening area is from approximately 25% to approximately 35% of the total screening area. 
     
     
         6 . The screen apparatus of  claim 4 , wherein the open screening area is from approximately 30% to approximately 35% of the total screening area. 
     
     
         7 . The screen apparatus  claim 1 , wherein the open screening area is from approximately 16% to approximately 35% of the total screening area. 
     
     
         8 . The screen apparatus of  claim 1 , wherein the size is in a range from approximately 35 μm to approximately 150 μm. 
     
     
         9 . The screen apparatus of  claim 8 , wherein the size is in a range from approximately 35 μm to less than 43 μm. 
     
     
         10 . The screen apparatus of  claim 1 , wherein the size is in a range from approximately 38 μm to approximately 150 μm. 
     
     
         11 . The screen apparatus of  claim 1 , wherein the single-piece screening element is micro-molded. 
     
     
         12 . The screen apparatus of  claim 1 , wherein the openings have a shape that is approximately rectangular, square, circular, or oval. 
     
     
         13 . The screen apparatus of  claim 1 , wherein the openings are elongated slots having a substantially uniform length L along a first direction, and a substantially uniform width W along a second direction, separated by surface elements having a thickness T along the second direction. 
     
     
         14 . The screen apparatus of  claim 13 , wherein the thickness T of the surface elements is in a range from approximately 0.003 inch to 0.020 inch. 
     
     
         15 . The screen apparatus of  claim 13 , wherein the width W of the surface elements is in a range from approximately 0.0015 inch to approximately 0.0059 inch. 
     
     
         16 . The screen apparatus of  claim 13 , wherein a length-to-width ratio L/W of the elongated slots has a value in a range from approximately 1:1 to approximately 30:1. 
     
     
         17 . The screen apparatus of  claim 13 , wherein:
 the surface elements have a thickness T that is approximately 0.014 inch.   
     
     
         18 . The screen apparatus of  claim 17 , wherein the open screening area is from approximately 30% to approximately 35% of the total screening area. 
     
     
         19 . The screen apparatus of  claim 13 , wherein:
 the surface elements have a thickness T that is approximately 0.007 inch.   
     
     
         20 . The screen apparatus of  claim 13 , wherein:
 the surface elements have a thickness T that is approximately 0.005 inch.   
     
     
         21 . The screen apparatus of  claim 13 , wherein:
 the surface elements have a thickness T that is approximately 0.003 inch.   
     
     
         22 . The screen apparatus of  claim 1 , wherein the open screening area is in a range from approximately 10% to approximately 15% of a total screening area. 
     
     
         23 . The screen apparatus of  claim 1 , wherein the thermoplastic polyurethane is obtained by a process in which a polyurethane prepolymer having a free polyisocyanate monomer content of less than 1% by weight is reacted with a curing agent and then processed by extrusion at temperatures of 150° C. or higher prior to the injection molding of the single injection molded piece. 
     
     
         24 . The screen apparatus of  claim 23 , wherein the polyurethane prepolymer is prepared from a polyisocyanate monomer and a polyol comprising an alkane diol, polyether polyol, polyester polyol, polycaprolactone polyol and/or polycarbonate polyol, and the curing agent includes a diol, triol, tetrol, alkylene polyol, polyether polyol, polyester polyol, polycaprolactone polyol, polycarbonate polyol, diamine or diamine derivative. 
     
     
         25 . The screen apparatus of  claim 1 , wherein the screen withstands an applied compression force in a range of about 1500 lbs. to about 3000 lbs. at a vibrational acceleration in a range of about 3G to about 10G and an operating temperature that is up to a value in a range of about 37° C. to about 94° C. 
     
     
         26 . The screen apparatus of  claim 1 , wherein the screen withstands applied compression forces of about 1500 lbs. to about 3000 lbs. at vibrational accelerations of up to about 10G and temperatures up to about 94° C. 
     
     
         27 . The screen apparatus of  claim 1 , wherein the composition comprises a flow agent in an amount of about 0.1% to about 5% by weight of the thermoplastic polyurethane. 
     
     
         28 . The screen apparatus of  claim 27 , wherein the flow agent comprises a wax. 
     
     
         29 . A screen apparatus, comprising
 a screening element including a composition that includes a thermoplastic polyurethane;   wherein the screening element is a single injection molded piece including openings generated during micro-molding of the single injection molded piece that melts the composition at a temperature in a range of about 148° C. to about 260° C. and injects the composition into a mold at an injection pressure in a range of about 400 psi to about 900 psi, the openings have a size that is in a range from approximately 35 μm to approximately 4000 μm, and the screening element has an open screening area of approximately 10% or more of a total screening area.   
     
     
         30 . The screen apparatus of  claim 29 , further comprising one or more additional screening elements in combination with the screening element, wherein each of the one or more additional screening elements is an additional single injection molded piece including additional openings generated during micro-molding of the additional single injection molded piece, the additional openings have the size that is in a range from approximately 35 μm to approximately 4000 μm, and each of the one or more additional screening elements has the open screening area of approximately 10% or more of the total screening area. 
     
     
         31 . The screen apparatus of  claim 30 , wherein the single-piece injection molded screening element and the one or more additional single-piece injection molded screening elements are joined using laser welding. 
     
     
         32 . The screen apparatus of  claim 29 , wherein the open screening area is 17% or more of the total screening area. 
     
     
         33 . The screen apparatus of  claim 29 , wherein the open screening area is from approximately 16% to approximately 35% of the total screening area 
     
     
         34 . The screen apparatus of  claim 33 , wherein the open screening area is from approximately 25% to approximately 35% of the total screening area. 
     
     
         35 . The screen apparatus of  claim 29 , wherein the size is in a range from approximately 35 μm to approximately 150 μm. 
     
     
         36 . The screen apparatus of  claim 35 , wherein the size is in a range from approximately 35 μm to less than 43 μm. 
     
     
         37 . The screen apparatus of  claim 29 , wherein the size is in a range from approximately 38 μm to approximately 150 μm. 
     
     
         38 . The screen apparatus of  claim 29 , wherein the screen withstands an applied compression force in a range of about 1500 lbs. to about 3000 lbs. at a vibrational acceleration in a range of about 3G to about 10G and an operating temperature that is up to a value in a range of about 37° C. to about 94° C. 
     
     
         39 . The screen apparatus of  claim 29 , wherein the screen withstands applied compression forces of about 1500 to about 3000 lbs. at vibrational accelerations of up to about 10G and temperatures up to about 94° C. 
     
     
         40 . The screen apparatus of  claim 29 , comprising a plurality of square feet in area. 
     
     
         41 . The screen apparatus of  claim 29 , wherein the open screening area is about 30% to about 35% of the total screening area. 
     
     
         42 . The screen apparatus of  claim 29 , wherein the openings range in size from approximately 43 μm to approximately 100 μm. 
     
     
         43 . A method of separating materials, comprising:
 placing the materials to be separated on a top surface of a screen positioned between a first wall and a second wall of a vibratory screening apparatus; and   exciting the screen to separate undersized materials of the materials from oversized materials of the materials to a desired level,
 the screen including a single-piece injection molded screening element, 
 the screening element including a composition including a thermoplastic polyurethane, 
 wherein the screen includes openings having a size that is in a range from approximately 35 μm to approximately 4000 μm, and the screen has an open screening area of approximately 10% or more of a total screening area, and the openings are generated during micro-molding of the single-piece screening element. 
   
     
     
         44 . The method of  claim 43 , wherein the screen further includes one or more additional single-piece injection molded screening elements in combination with the single-piece injection molded screening element, the one or more additional single-piece injection molded screening elements each include the composition, and the openings are generated during micro-molding of the single-piece screening element and the one or more additional single-piece screening elements. 
     
     
         45 . The method of  claim 43 , wherein the open screening area is 17% or more of the total screening area. 
     
     
         46 . The method of  claim 43 , wherein the open screening area is from approximately 10% to approximately 35% of the total screening area 
     
     
         47 . The method of  claim 46 , wherein the open screening area is from approximately 25% to approximately 35% of the total screening area. 
     
     
         48 . The method of  claim 47 , wherein the open screening area is from approximately 30% to approximately 35% of the total screening area. 
     
     
         49 . The method of  claim 43 , wherein the size is in a range from approximately 35 μm to approximately 150 μm. 
     
     
         50 . The method of  claim 49 , wherein the size is in a range from approximately 35 μm to less than 43 μm. 
     
     
         51 . The method of  claim 43 , wherein the size is in a range from approximately 38 μm to approximately 150 μm. 
     
     
         52 . The method of  claim 43 , wherein the vibratory screening apparatus excites the screen with vibrational accelerations of about 3G to about 10G. 
     
     
         53 . The method of  claim 43 , wherein the method is employed in at least one of the oil, gas, chemical, automotive, mining, and water purification industries. 
     
     
         54 . The method of  claim 43 , wherein the materials include a drilling mud.