Monofilament of polyamide, flat textile product and method for producing same

#This application is a 371 of International Patent Application No. PCT/US02/18896 filed Jun. 13, 2002, now WO 03/000742 A1 published Jan. 3, 2003 and which claims priority benefits from German patent application number DE 101 317 29.8 filed Jun. 21, 2001.

#The invention relates to a monofilament of polyamide, especially for flat textile products, for use in paper machines, for instance, as well as a flat textile product, a method for producing same and the use of a method for producing a flat textile product.

#Among other uses, such flat products are used as paper machine covers, e.g., as press felts. Press felts are conducted with the still moist paper web or cellulose web over rolls and through a series of roll pairs and water is removed from the moist web during this passage. The press felt serves not only as a carrying surface for the moist web, but also to absorb the water pressed out of the web. The water accumulating in the conveyor belt-like press felt is removed by dewatering devices, positioned for instance at a point where the paper web is no longer in direct contact with the press felt.

#The objective of the present invention is to propose a monofilament of polyamide which features improved mechanical properties, especially with regard to abrasion, strength and proneness to splitting, but also with regard to the modification of properties over the course of time. It is also the objective of the invention to propose a flat textile product, especially a forming wire or press felt, for use in cellulose fiber preparation or paper production, for instance, and a method for producing such a flat textile product.

#Under the present invention, the objective is attained by a monofilament of the type mentioned in the beginning, containing polyamide at the rate of 99.9% to 90% by weight, and a cross-linkage reinforcement agent at the rate of 0.1% to 10% by weight, the polyamide being at least partially cross-linked. The polyamide is a meltable, spinnable, thread-forming polyamide.

#Such a monofilament possesses the advantage that the molecule chains are bound to each other more closely and strongly as a result of the cross-linkage, which causes the formation of covalent bonds, thereby preventing the infiltration of water molecules between the molecule chains through the amorphous regions. Consequently, the hydrogen bridge linkages are no longer widened or loosened.