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 [...]

Basic Chemicals For Paper

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

Wood is a natural composite material and is far more complex than any man-made composite. Wood consists of fibers with lignin as a glue in between, and is thus a “fiber composite material”. The purpose of the pulping process is to separate the wood into individual fibers and to make the fibers suitable for papermaking. [...]

Requirements of Coated Papers for the Printing Process

2017-01-08T00:14:26+00:00 Categories: Coating|Tags: , , , , , , , , , |

Requirements of Coated Papers for the Printing Process Printed matters are used for advertising, news and information, transactions, edu¬cation, and entertainment. Here they are in competition with other communica¬tion media, such as radio and television, and the internet. Printing on packaging paper and board has the functions of advertising, delivering information, and showing data such [...]

Requirements of Base Papers : Board for Coating

2017-01-08T00:14:27+00:00 Categories: Coating|Tags: , , , , , , , |

Requirements of Base Papers/Board for Coating General Aspects Coated papers are classified as wood-containing or mechanical papers, and fine papers, which are also called woodfree, or WF papers. Wood-containing papers are made of a fiber furnish such as groundwood or other mechanical pulps. Recycled fibers (RCF) are also currently an important and steadily growing raw [...]