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Air-laid paper is a textile-like material categorized as a nonwoven fabric made from fluff pulp. [1]
| | This article needs additional citations for verification .(February 2022) |
Air-laid paper is a textile-like material categorized as a nonwoven fabric made from fluff pulp. [1]
Compared with normal wet-laid paper and tissue, air-laid paper is very bulky, porous and soft. It has good water absorption properties and is much stronger compared with normal tissue.
Main characteristics are:
Unlike the normal papermaking process, air-laid paper does not use water as the carrying medium for the fibre. Fibres are carried and formed to the structure of paper by air. The air-laid structure is isotropic.
The raw material is long fibered softwood fluff pulp in roll form. The pulp are defibrized in a hammermill. Defibration is the process of freeing the fibres from each other before entering the papermachine. Important parameters for dry defibration are shredding energy and knot content. Normally an air-laid paper consists of about 85% fibre. A binder must be applied as a spray or foam. Alternatively, additional fibres or powders can be added to the pulp which can then be activated and cured by heat.
The Danish inventor Karl Krøyer is considered to be the first who commercialized air-formed paper in the early 1980s. [2] Others developed different processes independently at about the same time. A Finnish company United Paper Mills(now UPM-Kymmene Oyj) was one of the companies developing airlaid technology in the 1980s. In the 1980s UPM formed a new company called Walkisoft Oy and also built an airlaid factory to Kotka Finland which started in 1985. Walkisoft built several plants around the world (including the world's largest airlaid-factory in Mt Holly, NC, USA) in the following 14 years before being sold to Buckeye Technologies Inc. The Walkisoft engineering team, which was responsible for the engineering and R&D of the airlaid machines, became known as Buckeye Engineering Finland and then, from 2002, as Anpap Oy, a private owned Finnish company. [3] [4]
Papermaking is the manufacture of paper and cardboard, which are used widely for printing, writing, and packaging, among many other purposes. Today almost all paper is made using industrial machinery, while handmade paper survives as a specialized craft and a medium for artistic expression.
Pulp is a fibrous lignocellulosic material prepared by chemically, semi-chemically or mechanically producing cellulosic fibers from wood, fiber crops, waste paper, or rags. Mixed with water and other chemicals or plant-based additives, pulp is the major raw material used in papermaking and the industrial production of other paper products.
UPM-Kymmene Oyj is a Finnish forest industry company. UPM-Kymmene was formed by the merger of Kymmene Corporation with Repola Oy and its subsidiary United Paper Mills Ltd in 1996. UPM consists of six business areas: UPM Fibres, UPM Energy, UPM Raflatac, UPM Specialty Papers, UPM Communication Papers and UPM Plywood. The Group employs around 17,000 people and it has production plants in 11 countries. UPM shares are listed on the NASDAQ OMX Helsinki stock exchange. UPM is the only paper company which is listed in the global Dow Jones Sustainability Index and also a member of the United Nations Global Compact organization.
A paper machine is an industrial machine which is used in the pulp and paper industry to create paper in large quantities at high speed. Modern paper-making machines are based on the principles of the Fourdrinier Machine, which uses a moving woven mesh to create a continuous paper web by filtering out the fibres held in a paper stock and producing a continuously moving wet mat of fibre. This is dried in the machine to produce a strong paper web.
Fiber crops are field crops grown for their fibers, which are traditionally used to make paper, cloth, or rope.
The kraft process (also known as kraft pulping or sulfate process) is a process for conversion of wood into wood pulp, which consists of almost pure cellulose fibres, the main component of paper. The kraft process involves treatment of wood chips with a hot mixture of water, sodium hydroxide (NaOH), and sodium sulfide (Na2S), known as white liquor, that breaks the bonds that link lignin, hemicellulose, and cellulose. The technology entails several steps, both mechanical and chemical. It is the dominant method for producing paper. In some situations, the process has been controversial because kraft plants can release odorous products and in some situations produce substantial liquid wastes.
Tissue paper or simply tissue is a lightweight paper or, light crêpe paper. Tissue can be made from recycled paper pulp on a paper machine.
Nonwoven fabric or non-woven fabric is a fabric-like material made from staple fibre (short) and long fibres, bonded together by chemical, mechanical, heat or solvent treatment. The term is used in the textile manufacturing industry to denote fabrics, such as felt, which are neither woven nor knitted. Some non-woven materials lack sufficient strength unless densified or reinforced by a backing. In recent years, non-wovens have become an alternative to polyurethane foam.
Coated paper is paper that has been coated by a mixture of materials or a polymer to impart certain qualities to the paper, including weight, surface gloss, smoothness, or reduced ink absorbency. Various materials, including kaolinite, calcium carbonate, bentonite, and talc, can be used to coat paper for high-quality printing used in the packaging industry and in magazines.
Ahlstrom Oyj is a manufacturer of fiber-based products. Renewable fibers represent about 95% of Ahlstrom's total fiber use.
Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, rags, grasses, or other vegetable sources in water, draining the water through a fine mesh leaving the fibre evenly distributed on the surface, followed by pressing and drying. Although paper was originally made in single sheets by hand, almost all is now made on large machines—some making reels 10 metres wide, running at 2,000 metres per minute and up to 600,000 tonnes a year. It is a versatile material with many uses, including printing, painting, graphics, signage, design, packaging, decorating, writing, and cleaning. It may also be used as filter paper, wallpaper, book endpaper, conservation paper, laminated worktops, toilet tissue, currency, and security paper, or in a number of industrial and construction processes.
Deinking is the industrial process of removing printing ink from paperfibers of recycled paper to make deinked pulp.
Liquid packaging board is a multi-ply paperboard with high stiffness, strong wet sizing and a high barrier coating, e.g. plastic. Only virgin paper fibers are used. The barrier coating must hold the liquid and prevent migration of air and flavors through the paperboard.
Electrical insulation papers are paper types that are used as electrical insulation in many applications due to pure cellulose having outstanding electrical properties. Cellulose is a good insulator and is also polar, having a dielectric constant significantly greater than one. Electrical paper products are classified by their thickness, with tissue considered papers less than 1.5 mils (0.0381 mm) thickness, and board considered more than 20 mils (0.508 mm) thickness.
Fluff pulp is a type of chemical pulp made from long fibre softwoods. Important parameters for fluff pulp are bulk and water absorbency.
The wet strength of paper and paperboard is a measure of how well the web of fibers holding the paper together can resist a force of rupture when the paper is wet. Wet strength is routinely expressed as the ratio of wet to dry tensile force at break.
Hydroentanglement is a bonding process for wet or dry fibrous webs made by either carding, airlaying or wet-laying, the resulting bonded fabric being a nonwoven. It uses fine, high pressure jets of water which penetrate the web, hit the conveyor belt and bounce back causing the fibres to entangle.
Repola Oy was a Finnish industrial conglomerate, between 1990 and 1995, in the engineering and forest industries.
Hemp paper is paper varieties consisting exclusively or to a large extent from pulp obtained from fibers of industrial hemp. The products are mainly specialty papers such as cigarette paper, banknotes and technical filter papers. Compared to wood pulp, hemp pulp offers a four to five times longer fibre, a significantly lower lignin fraction as well as a higher tear resistance and tensile strength. Because the paper industry's processes have been optimized for wood as the feedstock, production costs currently are much higher than for paper from wood.
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