Patent ID: 8591793

Claim:
A method for making a press felt with a smoothed permeable surface on its paper side for use in the press section of a paper machine, wherein the press felt comprises a nonwoven layer lying on its paper side surface, the paper side surface of said layer being bonded and fixed by a thermoplastic binding material, the method comprising the steps: making an untreated press felt containing the nonwoven layer and the thermoplastic binder material, in which the thermoplastic binder material is contained in the form of thermoplastic adhesive fibers and/or as thermoplastic adhesive component of bicomponent fibers, distributed in the nonwoven layer; heating the untreated press felt to a temperature lying above the melting point of the thermoplastic binder material; and cooling the heated press felt to a temperature lying below the melting point of the thermoplastic binder material while applying pressure with a smooth surface; wherein the untreated press felt is fashioned as an endless web and placed under tension around a heated calendar roller and another calendar roller , arranged in parallel with this, and with the paper side surface of the untreated press felt oriented against the surface of the heated calendar roller; wherein a cooling surface is arranged between the two calendar rollers pushing the web somewhat outward thereby applying a pressing force onto the paper side surface of the untreated press felt; wherein the untreated press felt is moved across the heated roller in order to heat it, and across the cooling surface to cool it down; and wherein the paper side surface of the nonwoven layer is smoothed by the application of pressure from the smooth cooling surface during the cooling of said layer surface from a temperature in excess of the melting temperature of the thermoplastic binding material to a temperature below this melting temperature.