The Paper Industry

The 2003 World Emulsion Polymer Demand Forecast 8.8 Million Metric Tons 

This chapter will cover the applications of emulsion polymers in the paper industry, especially in surface sizing and paper coating. Since information on the breakdown in the uses of emulsion polymers for surface sizing and paper coating is not readily available in the world markets, it is hoped that information available on the Western Europe market would provide some perspectives on their relative uses of emulsion polymers. Table 4-1 shows the amounts of emulsion polymers used for these applications in Western Europe 3 % and 97 %, respectively [2]. 

Market segment Amount of polymer dispersions in metric tons and percent (1997) 

The precursors of paper were papyrus and parchment, which were used for writing as early as 3000 BC in Egypt. In China, strips of bamboo or wood were used for writing and drawing before the discovery of paper. The invention of paper has been attributed to Ts ai Lun in AD 105, who produced a uniform writing-material paper from felted plant fibers [3]. The original paper was made in China from rags, bark 

In 1998, the world production of paper and paperboard excluding newsprint and tissue totaled approximately 240 million metric tons and is expected to grow to approximately 290 million metric tons in 2003 with an annual growth rate of 4 % [1]. 

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Manero J M, Masson D V, Marsai M and Pianeii J L 1999 Appiication of the technique of environmentai scanning eiectron microscopy to the paper industry Scanning 21 36-9... 

E. Hamilton and B. Leopold, eds.. Pulp and Paper Manufacture, Vol. 3, Secondary Fibers and Non-Wood Pulping, Joint Textbook Committee of the Paper Industry, Tappi, Adanta, Ga., 1987. 

Paper Industry Applications. Derivatives of bistriazinjistilbene (1) are used in the paper industry. 

Both types of xyloglucans exhibit monolayer sorption onto cellulose (116) and tamarind xyloglucan exhibits maximum specific sorption onto cellulose less than that of coniferous xylan. By inference with other data, this is also less than that of glucomannan and hardwood xylan, but similar to many additives used in the paper industry. 

D. Clayton and co-workers, "Chemistry of Alkaline Pulpiag," ia Eulp and Paper Manufacture, 3rd ed., Vol. 5, Alkaline Pulpiag, The Joiat Textbook Committee of the Paper Industry, TAPPI, CPPA, Technology Park Adanta, Ga., 1989. 

This purity is adequate for conversion into aqueous emulsions which are suppHed to the paper industry. 

The higher, long-chain dimers as weH as the tetramer dehydroacetic acid are far more stable and can be handled safely. The alkylketene dimers (AKDs) are shipped to the paper industry in tank tmcks in the form of ready-to-use aqueous emulsions with a total soHds content of 12—25% and a guaranteed shelf life of 30 days, as they have good hydrolytic stabHity. In this form they are not combustible Hquids, and are Hsted in the Canadian Domestic Substances List. 

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). 

Lists of the manufacturers of each type of product used by the paper industry are available (6). Surveys of chemical suppHers for the U.S. and Canadian pulp and paper industries have been pubHshed (7). 

In the paper industry, PEO is widely used as a retention aid and pitch control agent in the newsprint industry (118—135). Typically, a phenol formaldehyde-type resin is added to the substrate before the addition of PEO. The chemical that is added before PEO has been referred to as an enhancer. Recent pubHcations on designing enhancers that work with PEO have resulted in expanding the use of PEO in flocculation of several substrates (128,129). 

Aluminum sulfate has largely replaced alums for the major appHcations as a sizing agent in the paper industry and as a coagulant to clarify municipal and industrial water suppHes. In terms of worldwide production, it ranks third behind alumina and aluminum hydroxide, with markets in excess of 3 x 10 t/yr (19). 

Sodium aluminate is used in water purification, in the paper industry, for the after treatment of Ti02 pigment, and in the manufacture of aluminum containing catalysts and zeoHte. Worldwide markets are in the range of 125,000 t/yr (19). 

Whiteness and Brightness. Photometric instmments, originally developed by the paper industry, are used for these measurements. Values are compared against standard white pigments such as BaSO, Ti02, or MgO. 

Amino resins are used by the paper industry in large volume for a variety of apphcations. The resins are divided into two classes according to the mode of appHcation. Resins added to the fiber slurry before the sheet is formed are called wet-end additives and are used to improve wet and dry strength and stiffness. Resins appHed to the surface of formed paper or board, almost invariably together with other additives, are used to improve the water resistance of coatings, the sag resistance in ceiling tiles, and the scuff resistance in cartons and labels. 

J. V. Hatton, ed.. Pulp andPaper Technology Series, No. 5, Chip Quality Monograph,Textbook Committee of the Paper Industry, TAPPI Press, Adanta, Ga., 1979. 

In 1980, >1 one million ts of sodium sulfate were consumed in the United States, but this had declined to <600, 000 t by the end of 1994. The decline is partly a result of higher energy prices and more efficient use of Na2S04 by the paper industry. At one time the kraft paper industry consumed two-thirds of sodium sulfate production. Pressures on paper producers to clean effluent streams and reduce energy forced improvements in internal processes and recycling of sodium sulfate (11,12). 

Condensation dyes from 4-nitrotoluene-2-sulfonic acid are the most important of the stilbene dyes. Direct YeUow 11 (Cl 40000), discovered in 1883 and commonly known as Sun YeUow [1325-37-7] is widely used in the paper industry (2,4). 

CTO prices are closely tied to the cycles of the U.S. economy and the paper industry. They vary between 120 and 220 per metric ton. In 1995 they were close to 200/t (4). With 50% of pine wood being converted to linerboard valued at 400— 600 per ton, pulp manufacturers do not focus on optimum black Hquor soap recovery, which only amounts of 60—70 kg/1 of southern pine pulp. This soap is converted to 30—35 kg of CTO, worth 6— 7 or less than a Htde over 1% of the pulp value (5). This recovery is only 45% of the CTO available in the pine tree. With more care and higher CTO prices, 10—15 kg of additional CTO could be obtained per ton of pulp (6). 

The fully and super hydrolyzed PVA grades are preferred by the paper industry for their superior strength, greater adhesion to cellulose, better water resistance, and better foaming characteristics. However, the intermediate and partially hydrolyzed grades provide better surface filming characteristics on many paper and paperboard substrates. 

Both natural ground or precipitated calcium carbonate are available as dry products shipped in 22.7 kg multiwaH bags, supersacks, or in bulk via tmck and railcar. Calcium carbonate slurry, primarily used by the paper industry, is shipped by tmck and rail. The soflds content of these slurries is typically >70% by weight for ground products and 20—50% for precipitated. In the 1980s small precipitation plants were built at the site of large North American papermills. 

The most comprehensive set of test methods for calcium carbonate has been assembled by the Pulverized Limestone Division of the National Stone Association. Methods for particle size, brightness, +325 mesh (44 -lm), and percentage of calcium carbonate have been pubflshed standards are available and have been well characterized (5). The Technical Association of the Pulp and Paper Industry (TAPPl) has pubflshed methods for calcium carbonate used in the paper industry (6). 

The use of calcium carbonate in paint, paper, and plastics make up the principal part of the market. In the paper industry calcium carbonate products find two uses as a filler in the papermaking process and as a part of the coating on paper. 

Of the sodium sulfate produced in the United States the paper industry consumes 36%, 45% is used in detergents, and 10% in the glass industry (72). Powdered detergents are on the decline in favor of Hquids that do not use sodium sulfate. Since the pulp and paper industry are also using less, the price of sodium sulfate is fluctuating (see Sodium compounds). 

Properties. The properties of kaolin that make it useful in the paper industry are brightness, viscosity, and particle si2e and shape. 

Triglycerides are important constituents of resin. In softwood, the triglycerides account for 20—40% of total resin content, and in hardwood, 40—50%. The paper industry uses the term pitch for resins that create problems in paper machines. Traditionally, pitch is controlled or reduced by aging the wood, by use of chemicals to avoid deposits on the roUs, or by intensive washing of the pulp. AH these methods add to the cost of paper production. An alternative is to add a Upase to the pulp in a reaction lasting about one hour with the help of agitation. Results from Japanese paper mills show substantial... 

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