Fabrics for Paper and Board Production

Almost throughout the whole paper machine the paper web is in contact with fabrics on one or both sides. Hereby quahty issues such as surface characteristics of the paper or board are influenced as well as economic parameters, e. g. by ensuring continuous production by secure web guiding throughout the paper machine  

The main requirements forming fabrics have to meet are  

This means that the forming fabrics have in part to meet contradictory requirements, as for instance  

All these properties should be constant over the width and length of the individual fabric and over the whole lifetime, which should be as long as possible. 

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Fabrics for Paper and Board Production 1253 Warp Weft... 

PLA polymers have been proposed also as water-based emulsions. Emulsion applications may include paper and board coatings and pigments, paints, binders for non-woven fabrics, binders for building products, and adhesives. Lactic acid derivatives, to be used as chemical intermediates in products such as solvents, hot-melt adhesives, coatings, surfactants, acrylic esters, and agricultural intermediates [348]. 

Sheet Drying. At a water content of ca 1.2—1.9 parts of water per part of fiber, additional water removal by mechanical means is not feasible and evaporative drying must be employed. This is at best an efficient but cosdy process and often is the production botdeneck of papermaking. The dryer section most commonly consists of a series of steam-heated cylinders. Alternate sides of the wet paper are exposed to the hot surface as the sheet passes from cylinder to cylinder. In most cases, except for heavy board, the sheet is held closely against the surface of the dryers by fabrics of carefuUy controUed permeabiHty to steam and air. Heat is transferred from the hot cylinder to the wet sheet, and water evaporates. The water vapor is removed by way of elaborate air systems. Most dryer sections are covered with hoods for coUection and handling of the air, and heat recovery is practiced in cold climates. The final moisture content of the dry sheet usually is 4—10 wt %. 

Phenolic plastics. Collective designation for phenolic resin-based plastics. Phenolic resins are produced by condensation of phenol and/or its homologues, such as cresol, with an aldehyde, such as formaldehyde or with an aldehyde-releasing material such as hexamethylenetetramine. Phenol/formaldehyde and/or cresol/formaldehyde resins are used as binding materials in fibre board, laminated paper and fabrics. In phenolic moulding compounds, the proportion of filler (such as wood flour, rock flour, asbestos, stone powder, mica, glass fibre) can be equal to that of the resin. These thermosets can be processed by compression or injection moulding into black or dark-coloured products mainly for the electric industry. 

Oxide fibers are manufactured by thermal or chemical processes into a loose wool mat, which can then be fabricated into a flexible blanket combined with binders and formed into boards, felts, and rigid shapes or fabricated into ropes, textiles and papers. The excellent thermal properties of these products make them invaluable for high temperature industrial appHcations. 

Organic thin film transistors are fabricated with a low-temperature process. It is therefore possible to fabricate TFT arrays for flat panel displays in a low cost process. The substrates are low-cost and flexible such as polyethylene terepthalate (PET). The low cost, large area TFT arrays can be used for many applications, e.g. electronic paper, smart cards and remotely updateable posters and notice boards. Currently the amorphous-silicon-on-glass technology is used for such applications. This technology is very expensive. These applications will only become popular in marketplace if the cost of production is substantially reduced. This is the driving force for the R D effort in organic TFTs. 

Formaldehyde (CH2O) release was measured for seven types of consumer products pressed wood, urea formaldehyde foam materials, clothes, insulation, paper, fabric, and carpet. A modified Japanese Industrial Standard (JIS) desiccator test was used to measure release rate coefficients and to rank 53 products. Ten pressed wood products and five urea formaldehyde foam products showed the highest CH2O releases (1-34 mg m 2.day"b The remainder, representing all product types, had lower releases ranging from 680 yg m 2.day to nondetectable levels. In other studies, CH2O release was measured in a ventilated chamber for single samples of particle board, plywood, insulation, and carpet. 

Binders for building products such as ceramics, ceiling tiles, floor coatings and paper board Binders for pigmented paper coatings, ceramic materials and non-woven fabrics... 

Automotive interior door panels often use PVC latex as a binder for a high-loft fabric bonded to a backing board. This is then covered with vinyl-coated fabric, and the entire assembly placed in a dielectric sealing press, where it is both heat-sealed and embossed. PVC latex-coated paperboard stock also finds use in various packaging applications. When PVC latex is used to saturate, rather than coat, paper-board, the products are suitable for preparation of molded mats. 

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