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 [...]

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 [...]

Non-fiber Raw Materials For Paper

2017-01-08T00:14:25+00:00 Categories: Raw Materials|Tags: , , , , , , , , , |

Pigments as Fillers Mineral fillers have long been used in papermaking. While they can be found in different paper and board grades, printing and writing papers represent by far the most dominant area for their application. Initially, they were added to increase the weight of the sheet and to improve the writing properties. Today, there [...]

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. [...]

Fibrous Materials for Paper

2017-01-08T00:14:25+00:00 Categories: Raw Materials|Tags: , , , , , |

Fibrous Materials Overview Paper production is mainly based on fibrous raw material which may consist of primary or secondary fibers. Primary fibers are obtained directly from plant raw materials, mainly from wood and annual non-wood plants. Industrially, mostly thinnings and sawmill wastes are used. Secondary fibers are produced from re¬covered paper. Rags are used only [...]

Overview of the Manufacturing Process for Paper and Board : Part 1

2017-01-08T00:14:26+00:00 Categories: Introduction to paper|Tags: , , , , , , |

Overview of the Manufacturing Process for Paper and Board Papermaking today includes, in principle, the same process steps as applied for centuries: preparation of the fiber material, sheet or web forming, pressing, dry¬ing, sizing and smoothing. However, in the last two centuries much of the detail has changed. Each process step has undergone – and [...]

Historical Background and General Aspects

2017-01-08T00:14:26+00:00 Categories: Introduction to paper|Tags: , , , , , , |

Historical Background and General Aspects 1.3.1 Introduction Paper is defined internationally as a thin layer of mostly cellulosic plant fibers, produced on a screen by dewatering a slurry of fibers in water [2]. The slurry is called pulp. Despite recent developments (proteinic or synthetic fibers, chemical additives, coating, etc.) the “cellulosic plant [...]

Paper Bleaching Chemicals

2012-08-07T11:02:39+00:00 Categories: Chemical Additives|Tags: , , , , , , , , , |

When chemical pulp, mechanical pulp and deinked recycled fibers are used in the production of white papers e. g. printing and writing papers, hygiene paper (tissue) or white top of board, these pulps have to be bleached up to a certain brightness. The bleaching of chemical pulp (see Volume 1) is carried out in several [...]