A composite hot-melt adhesive mesh film and preparation process thereof, in particular, a composite hot-melt adhesive mesh film and preparation process thereof for bonding metal and non-polar material are disclosed. The mesh film is compounded of a polar polyamide hot-melt adhesive and a non-polar polyolefin hot-melt adhesive mesh film containing a compatibilizer. The mesh film has a high adhesive strength and a durable and stable adhesion, and is especially suitable for bonding stainless steel, aluminum, copper or other metal materials and polyethylene, polypropylene or other non-polar polymers. Additionally, the preparation process is completed in one set of production process from raw material pretreatment to the final preparation of the hot melt adhesive mesh film product, thereby greatly reducing production failures, and providing high production efficiency and low costs.

A process and apparatus for producing a dimensionally stable melt blown nonwoven fibrous web. The process includes forming a multiplicity of melt blown fibers by passing a molten stream including molecules of at least one thermoplastic semi-crystalline (co)polymer through at least one orifice of a melt-blowing die, subjecting at least a portion of the melt blown fibers to a controlled in-flight heat treatment operation at a temperature below a melting temperature of the at least one thermoplastic semi-crystalline (co)polymer immediately upon exiting from the at least one orifice, and collecting at least some of the melt blown fibers subjected to the controlled in-flight heat treatment operation on a collector to form a non-woven fibrous structure. The nonwoven fibrous structure exhibits a Shrinkage less than a Shrinkage measured on an identically-prepared structure including only fibers not subjected to the controlled in-flight heat treatment operation, and generally less than 15%.

A process and apparatus for producing a dimensionally stable melt blown nonwoven fibrous web. The process includes forming a multiplicity of melt blown fibers by passing a molten stream including molecules of at least one thermoplastic semi-crystalline (co)polymer through at least one orifice of a melt-blowing die, subjecting at least a portion of the melt blown fibers to a controlled in-flight heat treatment operation at a temperature below a melting temperature of the at least one thermoplastic semi-crystalline (co)polymer immediately upon exiting from the at least one orifice, and collecting at least some of the melt blown fibers subjected to the controlled in-flight heat treatment operation on a collector to form a non-woven fibrous structure. The nonwoven fibrous structure exhibits a Shrinkage less than a Shrinkage measured on an identically-prepared structure including only fibers not subjected to the controlled in-flight heat treatment operation, and generally less than 15%.

The present invention is directed to a method and a system for the production of at least one polymeric yarn comprising means for mixing a polymer (1) with a first solvent yielding a mixture; means for homogenizing the mixture; means for rendering the mixture inert (21, 22, 23); means for dipping the mixture into a quenching bath (30), wherein an air gap is maintained before the mixture reaches the quenching bath (30) liquid surface forming at least one polymeric yarn; means for drawing (41) the at least one polymeric yarn at least once; means for washing (5) the at least one polymeric yarn with a second solvent that is more volatile than the first solvent; means for heating the at least one polymeric yarn (6); means for drawing at room temperature (7) the at least one polymeric yarn at least once; and means for heat drawing (8) the at least one polymeric yarn at least once. The instant invention also concerns a system and method of dosing a polymer mixture with a first solvent into an extruder (26), a device (5), a system and a method of solvent extraction from at least one polymeric yarn, and a method and system of mechanical pre-recovery (4) of at least one liquid in at least one polymeric yarn.

The present invention is directed to a method and a system for the production of at least one polymeric yarn comprising means for mixing a polymer (1) with a first solvent yielding a mixture; means for homogenizing the mixture; means for rendering the mixture inert (21, 22, 23); means for dipping the mixture into a quenching bath (30), wherein an air gap is maintained before the mixture reaches the quenching bath (30) liquid surface forming at least one polymeric yarn; means for drawing (41) the at least one polymeric yarn at least once; means for washing (5) the at least one polymeric yarn with a second solvent that is more volatile than the first solvent; means for heating the at least one polymeric yarn (6); means for drawing at room temperature (7) the at least one polymeric yarn at least once; and means for heat drawing (8) the at least one polymeric yarn at least once. The instant invention also concerns a system and method of dosing a polymer mixture with a first solvent into an extruder (26), a device (5), a system and a method of solvent extraction from at least one polymeric yarn, and a method and system of mechanical pre-recovery (4) of at least one liquid in at least one polymeric yarn.

A method for tuning characteristics of a polyamide nanofiber nonwoven comprising the step of targeting a specific average nanofiber diameter and/or a specific relative viscosity for the polyamide nanofiber nonwoven. The specific average nanofiber diameter is within a range from 100 nm to 1000 nm and/or the specific relative viscosity is within a range from 5 to 75, e.g., from 15 to 50. The process further comprises the steps of extruding a polyamide composition having a moisture content with a pressurized gas through a fiber forming channel having a channel temperature to form the polyamide nanofiber nonwoven having the target average nanofiber diameter and/or relative viscosity and controlling the moisture content, the pressure of pressurized gas, and/or the channel temperature based on the specific average nanofiber diameter and/or the specific relative viscosity.

The method for producing non-core beta silicon carbide fibers includes four steps. The first step is spinning of multifilament polymeric fiber by melt-extrusion of polycarbosilane. The second step is thermooxidative cross-linking for which the produced spun polymeric fibers are cured in an oxidation furnace at a temperature of 175-250 degrees C. at a heating rate of 3-10 degrees C./h until their weight is increased by 6-15%. The third step is carbonization of the produced cured polymeric fibers with the conversion into the ceramic phase. The fourth step is finishing of the produced beta silicon carbide fiber. The effect of the invention is producing non-core silicon carbide fibers, improving their strength performance, improving resistance to high temperatures and their high creep resistance, stable fiber properties, optimal average diameter of fibers, absence of foreign impurities in the fiber composition.

The method for producing non-core beta silicon carbide fibers includes four steps. The first step is spinning of multifilament polymeric fiber by melt-extrusion of polycarbosilane. The second step is thermooxidative cross-linking for which the produced spun polymeric fibers are cured in an oxidation furnace at a temperature of 175-250 degrees C. at a heating rate of 3-10 degrees C./h until their weight is increased by 6-15%. The third step is carbonization of the produced cured polymeric fibers with the conversion into the ceramic phase. The fourth step is finishing of the produced beta silicon carbide fiber. The effect of the invention is producing non-core silicon carbide fibers, improving their strength performance, improving resistance to high temperatures and their high creep resistance, stable fiber properties, optimal average diameter of fibers, absence of foreign impurities in the fiber composition.

An apparatus for making a spunbond nonwoven from endless filaments of a thermoplastic synthetic resin has a spinneret for spinning the filaments in a filament-travel direction into a spinning zone and a monomer aspirator downstream of the spinneret and having two vacuum intake ports flanking the spinning zone zone, horizontally confronting each other, and each extending transversely to the direction opposite one another. Suction means connected to the two ports withdraws gas through both the vacuum intake ports. The suction and/or the ports are set up to vary the flow through the vacuum intake ports such that substantially more gas flows through one of the ports than through the other.

An apparatus for making a spunbond nonwoven from endless filaments of a thermoplastic synthetic resin has a spinneret for spinning the filaments in a filament-travel direction into a spinning zone and a monomer aspirator downstream of the spinneret and having two vacuum intake ports flanking the spinning zone zone, horizontally confronting each other, and each extending transversely to the direction opposite one another. Suction means connected to the two ports withdraws gas through both the vacuum intake ports. The suction and/or the ports are set up to vary the flow through the vacuum intake ports such that substantially more gas flows through one of the ports than through the other.