Impregnated blade coating

Abstract

A blade for treating fibrous nonwoven webs having a base body and a coating covering at least a part of the surface of the base body. The coating forms at least that part of the blade surface which is provided to come into contact with the fibrous nonwoven web. At the contact surface, the coating has an open-pored material, the pores of which are filled at least partly with a polymer.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This is a continuation of PCT application No. PCT / EP2011 / 070659, entitled “IMPREGNATED BLADE COATING”, filed Nov. 22, 2011, which is incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to blades for machines for the production of paper and, in particular to the configuration of blades for use in creping or coating of a paper web.[0004]2. Description of the Related Art[0005]In order to produce the surface properties required for a particular application purpose of a given paper type, the fibrous nonwoven web, or the so-called raw paper web, produced in the paper manufacturing process must, as a rule, be subjected to a separate treatment. In this regard, high quality paper types are coated and hygienic papers are creped.[0006]The creping process produces paper types having surface structures. Normally a blade called a creping doctor is applied with its working edge a...

AI Technical Summary

Benefits of technology

The patent describes a blade with good gliding properties and a dirt-repelling effect on its contact surface. This results in a longer lifespan for the blade and reduced risk of damage during service. The blade is coated with a polymer that contains an epoxy resin and a silicone-polyester resin to provide both sliding properties and dirt-repelling properties. Fillers, such as PFE, can be embedded in the polymer to improve its sliding and dirt-repelling properties. The coating base material is made of oxide ceramics or a mixture of oxide ceramics, such as aluminum oxide, zirconium dioxide, magnesium oxide, chromium (III) oxide, yttrium oxide, and titanate. The coating has a level of porosity between 2 and 10 percent, and the pores are small in size. An adhesive layer can be used to improve the adhesion of the coating onto the blade's base body.

Problems solved by technology

Since in the two processes strong forces act upon the blades, high demands are placed on the mechanical stability and wear resistance of the blades.

However, the wear and tear characteristics of these coating mediums do not permit extended standstills under the conditions prevailing during operation, so that creping doctors and doctor blades still need to be replaced in very short intervals in order to maintain the paper quality.

Particles and contaminants on and inside the paper web moreover lead to localized load peaks on the blades which regularly cause damage on the blade coating, thereby reducing the quality of the produced paper.

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