Board production

Cadmium usage, illegal in most of Europe, is being discouraged elsewhere. The U.S. military has cadmium specifications for electronic, fastener, and marine equipment, which requires only cadmium. Tin is being substituted for tin—lead as a metallic etch resist during printed circuit board production. 

The total production of the U.S. paper industry in 1994 was ca 85 million metric tons with a compound aimual growth rate over the previous decade of 2.7%. The domestic production of paper and board plus imports and minus exports maintains a remarkably constant ratio with real gross domestic product in the United States. One sector of the paper industry that has grown at a higher rate than GDP is recycled papers and boards which is projected to grow at 6.8% aimuaHy. Over one-half of paperboard production in the United States is from recycled fiber, and the industry as a whole is expected to achieve 50% recovery rate for paper and board products by the end of the twentieth century (see Recycling, paper). 

In recent years, lumber production has accounted for close to 40% of all roundwood used ia the United States (4). Pulp, paper, and board products have accounted for close to 30% of total roundwood used. Between 1965 and 1994, aimual production of lumber (ia board feet) iacreased by 26%. In contrast, production of paper and board (ia tons) more than doubled (4). 

C473-87a Physical Testing of Gypsum Board Products ... 

In 1989, 4,689,000 metric tons of uncalcined gypsum was sold or used 3,229,000 metric tons for use in Pordand cement and the remainder for agriculture and miscellaneous uses. About 17,778,000 metric tons of calcined material was used to produce 1.9 million square meters of board products. Over one million square meters of this material was regular board and about 560,000 m was Type X board. 

The cost of the chemicals used in electroless copper plating is very low, rarely exceeding 2.78/m, except for fully additive processes. The principal costs of printed circuit board production arise mainly from handling steps and other operations. 

However, it has to be considered that it is neither the content of free formaldehyde itself nor the molar ratio which eventually should be taken as the decisive and the only criterion for the classification of a resin concerning the subsequent formaldehyde emission from the finished board. In reality, the composition of the glue mix as well as the various process parameters during the board production also determine both performance and formaldehyde emission. Depending on the type of board and the manufacturing process, it is sometimes recommended to use a UF-resin with a low molar ratio F/U (e.g. F/U = 1.03), hence low content of free formaldehyde, while sometimes the use of a resin with a higher molar ratio (e.g. F/U = 1.10) and the addition of a formaldehyde catcher/depressant will give better results [17]. Which of these two, or other possible approaches, is the better one in practice can only be decided in each case by trial and error. 

The experience of the particleboard industry on the influence of seasonal variations of the wood quality has been reported. Problems occur especially using wood which has been harvested in the wintertime and which goes into board production immediately. 

There is growing interest in the use of cereal straws such as wheat straw for animal feed after increasing its digestibility by various methods, or as a raw material for paper and board production. This is particularly important in areas with limited forest resources (1). For all these purposes a good physicochemical characterisation of cereal straw is necessary. 

Abstract Paper for recycling is the most important fibre raw material of the German paper industry. 16.3 Mio t of paper for recycling was utilised in 2010 corresponding to 72% of the total fibre raw material input for paper and board production. In comparison to the used virgin fibre-based chemical and mechanical pulp, the utilised amount of paper for recycling is about 2.6 times higher. 

Reduction of the mineral oil input during recycled board production by using alternative chemical additives. 

Producers of board try to manufacture board for foodstuff packaging with other, less mineral oil-contaminated RCP grades. Major sources of mineral oil in paper for recycling are offset coldset inks preferably used in newspapers and which contain typically 20-30% mineral oil as solvent [12]. By appropriate sorting of the RCP, the theoretical possibility exists to remove newspapers from collected household paper mixtures, so-called household collections, so that a mixed RCP grade without newspaper is generated especially for board production. 

The substitution of recycled fibre-based boxboard for foodstuff and from corrugated boxes as transport packaging to virgin fibre-based products is impossible due to insufficient availability of fibres and of paper and board production capacity. 

Measures in RCP processing to reduce the mineral oil do not obtain the desired success so far. Development work on the finishing of board products with functional barriers is under progress. In both areas, further research needs exist. The use of inner bags as barrier against mineral oil migration is possible but cannot be used for all types of foodstuff. Here also exists research demand. 

Blattellaquinone, 27 259 Bleach activator, ethyleneamines application, 8 500t, 504-505 Bleach boosting, 70 304-305 Bleached board products, 78 130 Bleached chemo-thermo mechanical pulp (BCTMP), 74 57 Bleached montan wax, 9 677 Bleaches. See also Bleaching... 

The annual world production of paper and board is around 250 million metric tonnes, and well over half of this is produced in the US and EEC countries. A mere 1.2 million tonnes is produced in the whole of Africa. It is also consumed almost totally by the developed world and the per capita consumption of paper and board products varies hugely throughout the world (Table 1.1). 

In addition to fibre obtained directly from plant sources by chemical or mechanical treatment (virgin fibre), recycled fibre is also used and to an increasing extent for paper and board production. A breakdown of world fibre usage is given in Table 1.2 and the subject... 

Table 1.1 Annual per capita consumption (1991) of paper and board products in various regions world-wide.

Table 1.2 The source of fibre world-wide for paper and board production.

Figure 1.3 World-wide distribution of paper and board product types (1992).

The remarkable property of cellulose fibres which gives rise to their widespread use in paper and board products is their ability, when dried in contact with each other from water, to form a strong bond. Perhaps more importantly, this bond can be completely disrupted by the re-addition of water and this is the essential property which allows cellulosic fibres to be relatively easily recycled. 

Recycling clearly has an important bearing upon fibre supply. There are two important environmental aspects to waste paper recycling. The first of these is what is known as the utilisation rate of waste paper and is defined as the waste paper consumption as a proportion of total paper and board production. The second useful definition is the recovery rate, which is simply the amount of waste paper recovered as a percentage of total paper and board consumption. An example of the use of such figures is shown in Table 10.1. 

The principle of surface activation is to generate free radicals on the surface of the wood this then provides bonding sites on the wood surfaces for resin-free board production. The use of biological systems to generate surface radicals will be considered later, this section being concerned with the use of chemical systems for surface activation. 

Barsberg and Hassingboe (2003) noted that the use of enzymes for surface activation of fibres for board production can produce highly variable results and that the reasons for this are not understood. In order to further understand the process, they treated TMP fibres with a laccase from Trametes villosa for 1 hour and dried the fibres. A control set of fibres was subjected to an identical protocol, but with no enzyme present. Air-laid fibre mats were produced from the fibres, which were then hot-pressed to form 3 mm thickness boards. Varying amounts of wax were sprayed on to the fibres prior to board production. Both the MOE and the MOR of the composites increased with board density. Boards produced from enzyme-treated or control fibres exhibited no difference in MOE, but the MOR of boards formed from enzyme-treated fibres was higher above a density of 800 kg m . Wax addition resulted in a decrease in mechanical properties. At a board density of c. 930 kg m , the MOR was of the order of 23 MPa and the MOE 11 GPa. 

It is evident that the application of a biological catalyst, the enzyme, in a technical process (in this case particle board production) demands as conditiones sine qua non the following parameters ... 

Source Agriculture, industrial processes. Specifically, industrial plants for the production of pulp from timber or other fibrous materials, and paper or board production are responsible of 70% of the total organic carbon released directly into water from industry per year. 

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