The present invention provides a homopolypropylene having high strength and a low content of low molecular weights together with excellent processability, and a preparation method thereof.

The present invention provides a homopolypropylene having high strength and a low content of low molecular weights together with excellent processability, and a preparation method thereof.

A polyolefin material that comprises a thermoplastic composition that is annealed and thereafter drawn in a solid state is provided. The composition contains a continuous phase that includes a polyolefin matrix polymer and a nanoinclusion additive dispersed within the continuous phase in the form of discrete domains. A porous network is defined within the thermoplastic composition that includes a plurality of nanopores, wherein the thermoplastic composition has a glass transition temperature of from about 20 C. to about 50 C. as determined in accordance with ASTM E1640-13.

A polyolefin material that comprises a thermoplastic composition that is annealed and thereafter drawn in a solid state is provided. The composition contains a continuous phase that includes a polyolefin matrix polymer and a nanoinclusion additive dispersed within the continuous phase in the form of discrete domains. A porous network is defined within the thermoplastic composition that includes a plurality of nanopores, wherein the thermoplastic composition has a glass transition temperature of from about 20 C. to about 50 C. as determined in accordance with ASTM E1640-13.

A method for forming porous fibers is provided. The fibers are formed from a thermoplastic composition containing a continuous phase, which includes a matrix polymer, and a nanoinclusion additive that is at least partially incompatible with the matrix polymer so that it becomes dispersed within the continuous phase as discrete nano-scale phase domains. The method includes traversing a bundle of the fibers through a multi-stage drawing system that includes at least a first fluidic drawing stage and a second fluidic drawing stage. The first drawing stage employs a first fluidic medium having a first temperature and the second drawing stage employs a second fluidic medium having a second temperature. The first and second temperatures are both lower than the melting temperature of the matrix polymer, and the first temperature is greater than the second temperature.

A method for forming porous fibers is provided. The fibers are formed from a thermoplastic composition containing a continuous phase, which includes a matrix polymer, and a nanoinclusion additive that is at least partially incompatible with the matrix polymer so that it becomes dispersed within the continuous phase as discrete nano-scale phase domains. The method includes traversing a bundle of the fibers through a multi-stage drawing system that includes at least a first fluidic drawing stage and a second fluidic drawing stage. The first drawing stage employs a first fluidic medium having a first temperature and the second drawing stage employs a second fluidic medium having a second temperature. The first and second temperatures are both lower than the melting temperature of the matrix polymer, and the first temperature is greater than the second temperature.

The present invention relates to a nonwoven fabric comprising a plurality of polypropylene-containing fibers that form a nonwoven web, which fibers in addition contain a slip agent, the web has a side which is provided with an alternating pattern which consists of individualized bonded areas which bonded areas are in the form of rods which are arranged in the cross direction of the web, the alternating pattern of individualized bonded areas defines a non-bonded area, the web has a basis weight on the range of from 5-25 g/m.sup.2, the surface of the bonded areas is in the range of 5-20% of the total surface of the side, and the surface of the non-bonded area is in the range of 80-95% of the total surface of the side. The present invention further relates to a process for forming the nonwoven fabric.

The present invention relates to a nonwoven fabric comprising a plurality of polypropylene-containing fibers that form a nonwoven web, which fibers in addition contain a slip agent, the web has a side which is provided with an alternating pattern which consists of individualized bonded areas which bonded areas are in the form of rods which are arranged in the cross direction of the web, the alternating pattern of individualized bonded areas defines a non-bonded area, the web has a basis weight on the range of from 5-25 g/m.sup.2, the surface of the bonded areas is in the range of 5-20% of the total surface of the side, and the surface of the non-bonded area is in the range of 80-95% of the total surface of the side. The present invention further relates to a process for forming the nonwoven fabric.

Nonwoven fibrous webs including a multiplicity of (co)polymeric fibers made of a mixture including from about 50% w/w to about 99% w/w of at least one crystalline polyolefin (co)polymer, and from about 1% w/w to about 40% w/w of at least one hydrocarbon tackifier resin. A process for making the nonwoven fibrous webs includes heating the foregoing mixture to at least a Melting Temperature of the mixture to form a molten mixture, extruding this molten mixture through at least one orifice to form at least one filament, applying a gaseous stream to attenuate the at least one filament to form a plurality of discrete, discontinuous fibers, and cooling the plurality of discrete, discontinuous fibers to a temperature below the Melting Temperature and collecting the discrete discontinuous fibers as a nonwoven fibrous web. The nonwoven fibrous webs exhibit a Heat of Fusion measured using Differential Scanning Calorimetry of greater than 50 Joules/g.

Nonwoven fibrous webs including a multiplicity of (co)polymeric fibers made of a mixture including from about 50% w/w to about 99% w/w of at least one crystalline polyolefin (co)polymer, and from about 1% w/w to about 40% w/w of at least one hydrocarbon tackifier resin. A process for making the nonwoven fibrous webs includes heating the foregoing mixture to at least a Melting Temperature of the mixture to form a molten mixture, extruding this molten mixture through at least one orifice to form at least one filament, applying a gaseous stream to attenuate the at least one filament to form a plurality of discrete, discontinuous fibers, and cooling the plurality of discrete, discontinuous fibers to a temperature below the Melting Temperature and collecting the discrete discontinuous fibers as a nonwoven fibrous web. The nonwoven fibrous webs exhibit a Heat of Fusion measured using Differential Scanning Calorimetry of greater than 50 Joules/g.