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US 7,407,699 B2Granted
Extruded polypropylene sheets containing beta spherulites
AssigneeMayzo, Inc.
InventorPhilip Jacoby
Life of this patent
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AssigneeMayzo, Inc.
InventorPhilip Jacoby
Estimating the term…
Improved extruded polypropylene sheets containing a high level of beta crystallinity and A process for making such sheets are disclosed herein. The polypropylene sheets comprise a resinous polymer of propylene and an effective amount of beta spherulites. Uniaxially or biaxially oriented mesh structures produced from the disclosed sheets exhibit lower density, higher strength, and higher torsional rigidity than polypropylene meshes without beta spherulites. Thus, lighter weight mesh structures which meet all of the physical property requirements for end-use applications, such as reinforcing grids to stabilize concrete and soil in civil engineering and landfill applications, are produced. The lighter weight extruded beta-nucleated sheet can also be stretched at higher line speeds, thereby reducing manufacturing costs.
An oriented web produced from a perforated extruded sheet comprising a propylene polymer comprising beta-spherulites in an amount sufficient to produce a K-value of about 0.2 to 0.95 when measured by x-ray diffraction or to show a beta crystalline melting peak during the first or second heating scan when measured using a differential scanning calorimeter, wherein the oriented web is biaxially oriented and wherein the web has thickness in the node junction region between the machine direction and transverse direction strands that is at least 10% less than that of an otherwise identical biaxially oriented web made from a perforated, extruded propylene sheet with no added beta nucleant and the same starting sheet thickness and wherein the oriented web has a tensile strength measured at 2% elongation in the machine direction, that is at least 10% higher than that of an otherwise identical biaxially oriented web made from a perforated, extruded propylene sheet with no added beta nucleant and the same starting thickness.
An oriented web produced from a perforated extruded sheet comprising a propylene polymer comprising beta-spherulites in an amount sufficient to produce a K-value of about 0.2 to 0.95 when measured by x-ray diffraction or to show a beta crystalline melting peak during the first or second heating scan when measured using a differential scanning calorimeter, wherein the oriented web is uniaxially oriented and wherein the web has thickness in the node junction region between the machine direction and transverse direction strands that is at least 10% less than that of an otherwise identical uniaxially oriented web made from a perforated, extruded propylene sheet with no added beta nucleant and the same starting sheet thickness and wherein the oriented web has a tensile strength measured at 2% elongation in the machine direction, that is at least 10% higher than that of an otherwise identical uniaxially oriented web made from a perforated, extruded propylene sheet with no added beta nucleant and the same starting thickness.
A method for making a perforated oriented web, wherein the oriented web is uniaxially oriented or biaxially oriented and wherein the web has thickness in the node junction region between the machine direction and transverse direction strands that is at least 10% less than that of an otherwise identical uniaxially oriented or biaxially oriented web made from a perforated, extruded propylene sheet with no added beta nucleant and the same starting sheet thickness and wherein the oriented web has a tensile strength measured at 2% elongation in the machine direction, that is at least 10% higher than that of an otherwise identical biaxially oriented web made from a perforated, extruded propylene sheet with no added beta nucleant and the same starting thickness, the method comprising the steps of:
Dependencies are inferred from the claim text.