Disclosed are an industrial polyamide yarn, a preparation method therefor, and the use thereof. The raw materials for producing the industrial polyamide yarn include at least 1,5-pentanediamine and a linear aliphatic dibasic acid; or polyamide 5X obtained by the polymerization of 1,5-pentanediamine and a linear aliphatic dibasic acid as monomers. The industrial polyamide yarn according to an embodiment has the characteristics of a low water absorption, a good dimensional stability, a high fracture strength, and a good heat resistance.

A spinning die for melt-blowing has plastic passages, a hot air passage, and an opening surface, in which discharge ports and blowing ports open. Adjacent and closest two of the discharge ports are first and second proximate discharge ports. One of the blowing ports corresponding to the first proximate discharge port is a first proximate blowing port, and one of the blowing ports corresponding to the second proximate discharge port is a second proximate blowing port. The first proximate blowing port includes a guide portion that projects away from the center of the first proximate discharge port. The guide portion is formed such that, as the distance from the opening surface increases, the hot air flow guided by the guide portion flows to be separated away from the hot air flow blown onto the molten plastic discharged from the second proximate discharge port.

A spinning die for melt-blowing has plastic passages, a hot air passage, and an opening surface, in which discharge ports and blowing ports open. Adjacent and closest two of the discharge ports are first and second proximate discharge ports. One of the blowing ports corresponding to the first proximate discharge port is a first proximate blowing port, and one of the blowing ports corresponding to the second proximate discharge port is a second proximate blowing port. The first proximate blowing port includes a guide portion that projects away from the center of the first proximate discharge port. The guide portion is formed such that, as the distance from the opening surface increases, the hot air flow guided by the guide portion flows to be separated away from the hot air flow blown onto the molten plastic discharged from the second proximate discharge port.

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 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.

Provided is a crystalline silicon carbide fiber containing silicon carbide, boron nitride, and zirconium carbide and having a content of Si of 64% by weight or more and a content of C of 28% by weight or more, in which the average particle size of SiC crystal grains is 100 nm or more.

The present invention relates to a spinning nozzle apparatus for manufacturing a high-strength fiber. The spinning nozzle apparatus for manufacturing a high-strength fiber according to the present invention is designed to optimize a heating method for the spinning region of a spinning nozzle in the melt spinning process. The heat transfer method is optimized by disposing the spinning nozzle holes of spinning nozzle commercially available on the outside of, directly under the pack body and heating the spinning nozzle holes with a heating body. In addition, an instantaneous heat treatment at high temperature is adopted to control the molecular entanglement structure in the melted polymer, which enhances the drawability of the thermoplastic resin and hence improves the mechanical properties such as strength and elongation.

The present invention relates to a spinning nozzle apparatus for manufacturing a high-strength fiber. The spinning nozzle apparatus for manufacturing a high-strength fiber according to the present invention is designed to optimize a heating method for the spinning region of a spinning nozzle in the melt spinning process. The heat transfer method is optimized by disposing the spinning nozzle holes of spinning nozzle commercially available on the outside of, directly under the pack body and heating the spinning nozzle holes with a heating body. In addition, an instantaneous heat treatment at high temperature is adopted to control the molecular entanglement structure in the melted polymer, which enhances the drawability of the thermoplastic resin and hence improves the mechanical properties such as strength and elongation.

An ultrafine fiber production device has a first heating unit, a nozzle unit, a hot air heating unit, a hot air blowing unit, a second heating unit, and a fiber collecting unit. The first heating unit melts a thermoplastic resin. The nozzle unit discharges the thermoplastic resin melted by the first heating unit. The hot air blowing unit performs fiber forming by blowing high-temperature gas produced by the hot air heating unit to the melted thermoplastic resin discharged by the nozzle unit and by extending the thermoplastic resin. The second heating unit further heats, extends, and fines produced fibers. The fiber collecting unit collects the thermoplastic resin in a fibrous form which is fined by the second heating unit.

An ultrafine fiber production device has a first heating unit, a nozzle unit, a hot air heating unit, a hot air blowing unit, a second heating unit, and a fiber collecting unit. The first heating unit melts a thermoplastic resin. The nozzle unit discharges the thermoplastic resin melted by the first heating unit. The hot air blowing unit performs fiber forming by blowing high-temperature gas produced by the hot air heating unit to the melted thermoplastic resin discharged by the nozzle unit and by extending the thermoplastic resin. The second heating unit further heats, extends, and fines produced fibers. The fiber collecting unit collects the thermoplastic resin in a fibrous form which is fined by the second heating unit.