Paper Bleaching Chemicals : Paper Bleaching Auxiliaries

2017-01-08T00:14:16+00:00 Categories: Chemical Additives|Tags: , , , , , , , , , , |

Paper Bleaching Auxiliaries These products enable a more efficient bleaching of the chemical, mechanical and deinked pulps and lead to increased whiteness. They are generally based on sur¬face active agents, i. e. wetting agents (see Section 3.6.7.) which are resistant to bleaching chemicals as well as chelating (complexing) agents (see Section 3.6.3.). Some of the [...]

Paper Bleaching Chemicals : Bleaching Substances

2017-01-08T00:14:16+00:00 Categories: Chemical Additives|Tags: , , , , , , , , , |

Bleaching Substances . • Chlorination (C) with chlorine, an effective, selective and inexpensive bleaching agent that reacts very fast with lignin. For environmental reasons during the last ten years chlorine is being substituted by chlorine dioxide, ozone and/or oxygen all over the world. In Europe substitution is already 100 %. In this particular case bleached [...]

Influencing Printability in Paper Coating

2017-01-08T00:14:16+00:00 Categories: Paper Coating Chemicals|Tags: , , , , , , , , , , , |

Influencing Printability in Paper Coating The evenness of the printed image is a very important criterion for quality. The acceptance of coated paper by printers depends on its runnability in the printing process and its printability in terms of an even image that is free of defects. The printability of paper is principally determined by [...]

Paper Coating Machines : General

2012-03-14T12:23:08+00:00 Categories: Paper Coating Machines|Tags: , , , , , , , , , |

Paper Coating Machines Overview Coating machines are separate machines in which a previously produced dry base paper is unwound, coated, dried, and then reeled again (Fig. 7.24). In contrast to coating applicators placed on-line in a paper machine (Section 6.8), they are usu¬ally called “off-line coaters” or “OMC” (off-machine coaters).   In a paper mill, [...]

Paper Coating Machines : Blade And Rod Coating

2017-01-08T00:14:16+00:00 Categories: Paper Coating Machines|Tags: , , , , , , , , , |

Direct Coating In direct coating, the web is supported by a backing roll and the coating medium is fed in excess onto the web. After a certain distance, defining the “dwell time”, the coat layer is metered down to the final thickness, being the desired coat weight. In the “roll applicator” or “LDTA” (long dwell [...]

Paper Coating Machines : Film Press , Metering Rod

2012-03-14T12:22:03+00:00 Categories: Paper Coating Machines|Tags: , , , , , , , , , |

Indirect Coating As an alternative to direct coating, a film press can be used for the application of coating media. The film press was derived from the size press, which is used for the application of starch or size solutions. Today, a wide variety of coating media are applied, including pigment dispersions with high solids [...]

Paper Coating Machines : Curtain Coating

2012-03-14T12:21:52+00:00 Categories: Paper Coating Machines|Tags: , , , , , , , , , |

Curtain Coating Besides film and blade coating, curtain coating is used for the application of coat¬ing media onto paper surfaces. Although curtain coating is a very old application technique, going back to the end of the 19th century, it has only been used for coating of paper since the 1990s. Curtain coating is mainly used [...]

Influencing Printability in Paper Coating

2017-01-08T00:14:17+00:00 Categories: Paper Coating Chemicals|Tags: , , , , , , , , , , , |

Influencing Printability in Paper Coating The evenness of the printed image is a very important criterion for quality. The acceptance of coated paper by printers depends on its runnability in the printing process and its printability in terms of an even image that is free of defects. The printability of paper is principally determined by [...]

Paper Coating : Influencing Porosity, Print Gloss and Glueability

2017-01-08T00:14:17+00:00 Categories: Paper Coating Chemicals|Tags: , , , , , , , , , , , , |

Influencing Porosity, Print Gloss and Glueability The gloss of the printed paper is determined by the smoothness of the paper surface and the ink holdout. In turn, the ink holdout is mainly determined by the porosity and the chemical and physical structure of the coated surface. Coatings need to be porous on a microscopic scale [...]

Paper Coating : Influencing Opacity,Smoothness and Gloss

2012-03-02T16:01:08+00:00 Categories: Paper Coating Chemicals|Tags: , , , , , , , , , , , , |

Influencing Opacity The main contribution to opacity has to come from the pigments. Synthetic prod¬ucts are usually less opaque than natural products and this can be a problem, especially when coating ULWC (ultra light weight) grades of paper. Products with a very pronounced thickening effect are only added in small quantities, so they hardly have [...]