Papermakers fabric of nonwoven layers in a laminated construction

DETAILED DESCRIPTION The present invention relates to a papermakers fabric which generally comprises a plurality of impervious nonwoven sheets joined together in a laminated arrangement to define the fabric.
Defined throughout the fabric are a series of drainage apertures which are created in the fabric by conventional techniques, such as laser drilling.
Each layer of the papermakers fabric is chosen to serve a particular purpose.
For example, if the laminated fabric is to be used as a forming fabric, then the layer that contacts the paper slurry is made of a highly abrasion resistant material.
The same is true of the layer that contacts the dewatering screen during the initial paper formation process.
The remaining layers are chosen to provide the papermakers fabric with desirable characteristics important to its intended use.
For example, one of the layers might be a material exhibiting high tensile strength to add strength and rigidly to the fabric.
Another layer might be acid resistant.
In addition, another layer might be antistatic, to combat a condition which is very prevalent in dryer fabrics.
Thus, it can be appreciated that, depending on the intended use, the number of layers and the materials constituting the layers may differ from fabric to fabric.
For certain applications, it is desirable to produce the drainage apertures or holes after the various layers have been laminated together.
For other applications, it is desirable to produce apertures for varying sizes in the individual layers and then to laminate the layers together so as to create capillary channels of varying size.
For still other applications, it is desirable to incorporate yarns between the foils.
For wet press felt applications, a basic laminated fabric is incorporated with a traditional batt material secured to the base fabric by glue, resin or similar adhesives.
Through the use of layered materials, it is possible to repair and splice a papermakers fabric while it is in its position of intended use.
The destroyed area of the belt may be removed and a ew piece may be inserted by building up the various layers on a corresponding basis through ultrasonic welding