Abstract: A process for the production of virtually full density polyolefin suitable for further processing by drawing to form a high tenacity, highly oriented polyolefin sheet comprising: a) feeding a metered amount of polyolefin powder into the nip between two vertically stacked and heated calender rolls through application of the polyolefin powder to the apex of the topmost of the two heated calender rolls; b) rolling the powder through the nip until a coherent sheet of polyolefin sheet is produced: and c) once a coherent polyolefin sheet exits the nip adjusting the temperature in the nip to obtain specific tensile and elongation properties. Apparatus for the performance of such a process is also described.

Abstract: A ballistic-resistant panel in which the entire panel or a strike-face portion thereof is formed of a plurality of sheets of high modulus high molecular weight polyethylene tape. The sheets of high modulus polyethylene tape can be in the form of cross-plied laminated layers of tape strips or a woven fabric of tape strips. The strips of UHMWPE tape include a width of at least one inch and a modulus of greater than 1400 grams per denier. The ballistic-resistant panel may include a backing layer of conventional high modulus fibers embedded in resin. A wide variety of adhesives were found acceptable for bonding the cross-plied layers of high modulus polyethylene tape together for forming the ballistic-resistant panels of the present invention.

Abstract: A ballistic-resistant panel in which the entire panel or a strike-face portion thereof is formed of a plurality of sheets of high modulus high molecular weight polyethylene tape. The sheets of high modulus polyethylene tape can be in the form of cross-plied laminated layers of tape strips or a woven fabric of tape strips. The strips of UHMWPE tape include a width of at least one inch and a modulus of greater than 1400 grams per denier. The ballistic-resistant panel may include a backing layer of conventional high modulus fibers embedded in resin. A wide variety of adhesives were found acceptable for bonding the cross-plied layers of high modulus polyethylene tape together for forming the ballistic-resistant panels of the present invention.

Abstract: A process for the production of a non-fibrous ultra high molecular weight polyethylene tape having a width of 1-inch or greater and a modulus of 1,400 grams per denier or greater. The non-fibrous UHMWPE tape is obtained by compression molding ultrahigh molecular weight polyethylene powder at a temperature below its melting point and then drawing and stretching the entire resultant compression molded UHMWPE sheet, with no slitting or splitting of the sheet, at a draw ratio of at least 100:1. The UHMWPE tape can be produced in weights of 6,000 to 90,000 denier or greater. The UHMWPE tape of the present invention minimizes the effect of stress concentrators that are prevalent with fibers and thereby enables the tape to be drawn at much higher draw ratios than is possible with fibrous UHMWPE. When used in ballistics panels, the high modulus high molecular weight polyethylene tape of the present invention improves ballistic performance by providing enhanced dissipation of the impact energy of a projectile.

Abstract: A process for the production of virtually full density polyolefin suitable for further processing by drawing to form a high tenacity, highly oriented polyolefin sheet comprising: a) feeding a metered amount of polyolefin powder into the nip between two heated calender rolls; b) rolling the powder through the nip under these conditions until a coherent sheet of polyolefin is produced. According to a highly preferred embodiment, initially, the nip is set at a gap smaller than the size of the smallest polyolefin powder particle and at a temperature above the melting point of the powder and once a coherent sheet of polyolefin exits the nip the temperature in the nip is lowered to a temperature below the melting point of the polyolefin powder and the gap increased to a desired level above the thickness of the largest powder particle.

Abstract: A process for the production of virtually full density polyolefin suitable for further processing by drawing to form a high tenacity, highly oriented polyolefin sheet comprising: a) feeding a metered amount of polyolefin powder into the nip between two heated calender rolls initially set at a gap smaller than the size of the smallest polyolefin powder particle and at a temperature above the melting point of the powder; b) rolling the powder through the nip under these conditions until a coherent sheet of polyolefin is produced: and c) once a coherent sheet of polyolefin exits the nip lowering the temperature in the nip to a temperature below the melting point of the polyolefin powder and increasing the gap to a desired level above the thickness of the largest powder particle. Apparatus for the performance of such a process is also described.

Abstract: A process for the production of virtually full density polyolefin suitable for further processing by drawing to form a high tenacity, highly oriented polyolefin sheet comprising: a) feeding a metered amount of polyolefin powder into the nip between two heated calender rolls; b) rolling the powder through the nip under these conditions until a coherent sheet of polyolefin is produced. According to a highly preferred embodiment, initially, the nip is set at a gap smaller than the size of the smallest polyolefin powder particle and at a temperature above the melting point of the powder and once a coherent sheet of polyolefin exits the nip the temperature in the nip is lowered to a temperature below the melting point of the polyolefin powder and the gap increased to a desired level above the thickness of the largest powder particle.

Abstract: A process for the production of virtually full density polyolefin suitable for further processing by drawing to form a high tenacity, highly oriented polyolefin sheet comprising: a) feeding a metered amount of polyolefin powder into the nip between two heated calender rolls initially set at a gap smaller than the size of the smallest polyolefin powder particle and at a temperature above the melting point of the powder; b) rolling the powder through the nip under these conditions until a coherent sheet of polyolefin is produced: and c) once a coherent sheet of polyolefin exits the nip lowering the temperature in the nip to a temperature below the melting point of the polyolefin powder and increasing the gap to a desired level above the thickness of the largest powder particle. Apparatus for the performance of such a process is also described.

Abstract: A non-fibrous ultra high molecular weight polyethylene tape having a width of 1-inch or greater and a modulus of 1,400 grams per denier or greater. The non-fibrous UHMWPE tape is obtained by compression molding ultrahigh molecular weight polyethylene powder at a temperature below its melting point and then drawing and stretching the entire resultant compression molded UHMWPE sheet, with no slitting or splitting of the sheet, at a draw ratio of at least 100:1. The UHMWPE tape can be produced in weights of 6,000 to 90,000 denier or greater. The UHMWPE tape of the present invention minimizes the effect of stress concentrators that are prevalent with fibers and thereby enables the tape to be drawn at much higher draw ratios than is possible with fibrous UHMWPE. When used in ballistics panels, the high modulus high molecular weight polyethylene tape of the present invention improves ballistic performance by providing enhanced dissipation of the impact energy of a projectile.

Abstract: A process for the production of a non-fibrous ultra high molecular weight polyethylene tape having a width of 1-inch or greater and a modulus of 1,400 grams per denier or greater. The non-fibrous UHMWPE tape is obtained by compression molding ultrahigh molecular weight polyethylene powder at a temperature below its melting point and then drawing and stretching the entire resultant compression molded UHMWPE sheet, with no slitting or splitting of the sheet, at a draw ratio of at least 100:1. The UHMWPE tape can be produced in weights of 6,000 to 90,000 denier or greater. The UHMWPE tape of the present invention minimizes the effect of stress concentrators that are prevalent with fibers and thereby enables the tape to be drawn at much higher draw ratios than is possible with fibrous UHMWPE. When used in ballistics panels, the high modulus high molecular weight polyethylene tape of the present invention improves ballistic performance by providing enhanced dissipation of the impact energy of a projectile.

Abstract: A non-fibrous ultra high molecular weight polyethylene tape having a width of 1-inch or greater and a modulus of 1,400 grams per denier or greater. The non-fibrous UHMWPE tape is obtained by compression molding ultrahigh molecular weight polyethylene powder at a temperature below its melting point and then drawing and stretching the entire resultant compression molded UHMWPE sheet, with no slitting or splitting of the sheet, at a draw ratio of at least 100:1. The UHMWPE tape can be produced in weights of 6,000 to 90,000 denier or greater. The UHMWPE tape of the present invention minimizes the effect of stress concentrators that are prevalent with fibers and thereby enables the tape to be drawn at much higher draw ratios than is possible with fibrous UHMWPE. When used in ballistics panels, the high modulus high molecular weight polyethylene tape of the present invention improves ballistic performance by providing enhanced dissipation of the impact energy of a projectile.

Abstract: A ballistic-resistant panel in which the entire panel or a strike-face portion thereof is formed of a plurality of sheets of high modulus high molecular weight polyethylene tape. The sheets of high modulus polyethylene tape can be in the form of cross-plied laminated layers of tape strips or a woven fabric of tape strips. The strips of UHMWPE tape include a width of at least one inch and a modulus of greater than 1400 grams per denier. The ballistic-resistant panel may include a backing layer of conventional high modulus fibers embedded in resin. A wide variety of adhesives were found acceptable for bonding the cross-plied layers of high modulus polyethylene tape together for forming the ballistic-resistant panels of the present invention.

Abstract: A ballistic resistant panel including a strike face portion and a backing portion. The strike face portion includes a plurality of interleaved layers of non-fibrous ultra high molecular weight polyethylene tape. The backing portion includes a plurality of interleaved layers of cross-plied fibers of ultra high molecular weight polyethylene. The entire stack of interleaved layers is compressed at high temperature and pressure to form a ballistic resistant panel having a strike face on one side. It has been found that ballistic resistance increases as the weight ratio of the strike face portion with respect to the backing portion decreases. A composite panel having a strike face Tensylon tape with at most 40% of the total weight of the panel exhibits improved ballistic resistance properties as compared to a monolithic structure of strictly interleaved layers of cross-plied high modulus fibers.

Abstract: A non-fibrous ultra high molecular weight polyethylene tape having a width of 1-inch or greater and a modulus of 1,400 grams per denier or greater. The non-fibrous UHMWPE tape is obtained by compression molding ultrahigh molecular weight polyethylene powder at a temperature below its melting point and then drawing and stretching the entire resultant compression molded UHMWPE sheet, with no slitting or splitting of the sheet, at a draw ratio of at least 100:1. The UHMWPE tape can be produced in weights of 6,000 to 90,000 denier or greater. The UHMWPE tape of the present invention minimizes the effect of stress concentrators that are prevalent with fibers and thereby enables the tape to be drawn at much higher draw ratios than is possible with fibrous UHMWPE. When used in ballistics panels, the high modulus high molecular weight polyethylene tape of the present invention improves ballistic performance by providing enhanced dissipation of the impact energy of a projectile.

Abstract: A ballistic-resistant molded article having a sandwich-type structure including two outer portions of a first high modulus material surrounding an inner portion of a second high modulus material. The outer portions are comprised of a plurality of interleaved layers of adhesive coated cross-plied non-fibrous ultra high molecular weight polyethylene tape. The inner portion is comprised of a plurality of interleaved layers of high modulus cross-plied fibers embedded in resin. The stack of interleaved layers is compressed at high temperature and pressure to form a hybrid sandwich ballistic-resistant molded article that includes a mix of high modulus materials. It has been found that ballistic resistance is higher for the hybrid structure than for a monolithic structure of comparable areal density.

Abstract: A wide sheet of highly oriented ultra high molecular weight polyethylene comprising a plurality of strips of highly oriented ultra high molecular weight polyethylene partially overlapped or abutted longitudinally to define joints between adjoining strips wherein the thickness of the joint is less than about 80% of the thickness of the sum of the thicknesses of the adjoining strips that make up the joint. A continuous method for the production of such materials comprising subjecting longitudinally overlapping or abutted strips of these materials to temperatures below the melting point of the UHMWPE and pressures over 300 pli is also disclosed.

Abstract: A ballistic-resistant panel in which the entire panel or a strike-face portion thereof is formed of a plurality of sheets of high modulus high molecular weight polyethylene tape. The sheets of high modulus polyethylene tape can be in the form of cross-plied laminated layers of tape strips or a woven fabric of tape strips. The strips of UHMWPE tape include a width of at least one inch and a modulus of greater than 1400 grams per denier. The ballistic-resistant panel may include a backing layer of conventional high modulus fibers embedded in resin. A wide variety of adhesives were found acceptable for bonding the cross-plied layers of high modulus polyethylene tape together for forming the ballistic-resistant panels of the present invention.

Abstract: A process for the production of virtually full density polyolefin suitable for further processing by drawing to form a high tenacity, highly oriented polyolefin sheet comprising: a) feeding a metered amount of polyolefin powder into the nip between two heated calender rolls; b) rolling the powder through the nip under these conditions until a coherent sheet of polyolefin is produced. According to a highly preferred embodiment, initially, the nip is set at a gap smaller than the size of the smallest polyolefin powder particle and at a temperature above the melting point of the powder and once a coherent sheet of polyolefin exits the nip the temperature in the nip is lowered to a temperature below the melting point of the polyolefin powder and the gap increased to a desired level above the thickness of the largest powder particle.

Abstract: A process for the production of virtually full density polyolefin suitable for further processing by drawing to form a high tenacity, highly oriented polyolefin sheet comprising: a) feeding a metered amount of polyolefin powder into the nip between two heated calender rolls initially set at a gap smaller than the size of the smallest polyolefin powder particle and at a temperature above the melting point of the powder; b) rolling the powder through the nip under these conditions until a coherent sheet of polyolefin is produced: and c) once a coherent sheet of polyolefin exits the nip lowering the temperature in the nip to a temperature below the melting point of the polyolefin powder and increasing the gap to a desired level above the thickness of the largest powder particle. Apparatus for the performance of such a process is also described.

Abstract: A process for the production of virtually full density polyolefin suitable for further processing by drawing to form a high tenacity, highly oriented polyolefin sheet comprising: a) feeding a metered amount of polyolefin powder into the nip between two heated calender rolls initially set at a gap smaller than the size of the smallest polyolefin powder particle and at a temperature above the melting point of the powder; b) rolling the powder through the nip under these conditions until a coherent sheet of polyolefin is produced: and c) once a coherent sheet of polyolefin exits the nip lowering the temperature in the nip to a temperature below the melting point of the polyolefin powder and increasing the gap to a desired level above the thickness of the largest powder particle. Apparatus for the performance of such a process is also described.