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 [...]

Paper Coating Machines : Application Concepts

2012-03-14T12:21:41+00:00 Categories: Paper Coating Machines|Tags: , , , , , , , , , |

Paper Coating Machine Application Concepts Typical coat weights for graphic papers are given in Fig. 7.28, plotted against the basis weight of the base paper. The coat weight is typically 25–40 % of the final basis weight of the paper. Wood-containing papers are mainly single-coated (LWC). Coat weights are usu¬ally between 6 and 10 g [...]

Paper Coating Machines : Coating Machine Driers

2017-01-08T00:14:20+00:00 Categories: Paper Coating Machines|Tags: , , , , , , , , , |

Coating Machine Driers After its application, the wet coat must be dried. Three different drying principles are used: radiation (infrared), convection (hot air), and contact (cylinders). Infrared drying yields a very good energy transport, whereas mass transfer is inferior. Therefore, infrared is especially suitable for heating the paper or board web to temperatures where considerable [...]

Introduction

2017-01-08T00:14:25+00:00 Categories: Chemical Additives|Tags: , , , , , , , , |

Natural chemical additives have played an important role in the raw material prep¬aration stage since the earliest beginnings of handmade papermaking more than two thousand years ago. Up to the end of the eighteenth century, chemical ad¬ditives from natural resources were used to increase paper strength, to generate better writing and printing characteristics, to enhance [...]

Paper Roll Handling

2017-01-08T00:14:26+00:00 Categories: Paper Finishing And Slitting|Tags: , , , , , , , , , , , |

Paper Roll Handling 8.2.1 Objective and General Description of Roll Handling The objective of roll handling is to prepare the finished paper rolls for shipment in such a way that they arrive at the end user in the best possible condition. The mill can contribute to this aim by two means, i. e. by very [...]

Process Chemicals For Paper

2017-01-08T00:14:28+00:00 Categories: Chemical Additives|Tags: , , , , , |

Process chemicals are all additives which are used to solve or prevent problems in the paper manufacturing process, to improve its efficiency and/or to provide eco¬logical advantages. For example these additives allow reduction in the consump¬tion of fresh water and energy, the prevention of foam and deposits, the improve¬ment of drainage and/or reduction in fiber [...]