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 [...]

Paper Coating OBA Carriers

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

Paper Coating OBA Carriers Optical brighteners work only when they are fixed to a carrier. A good carrier is linear and contains OH- or other hydrophilic groups. Linearity increases the con¬tact between the carrier and OBA so that physical bonds (such as hydrogen bonds and van der Waals forces) can be formed between the OBA [...]

Paper Coating Optical Brightening Agents (OBA)

2012-03-02T15:55:06+00:00 Categories: Paper Coating Chemicals|Tags: , , , , , , , , , , , , |

Paper Coating Optical Brightening Agents (OBA) The brightness of paper and board has increased dramatically during recent years. The brightness of pulp, fillers and coating pigments is not high enough to reach these brightness targets. Therefore there is a need to use a coating additive called an optical brightener. These products are also known under [...]