Literature

How Paper is Made/Highlights. This is a one- to two-hour CD-ROM, based on the three-CD set entitled How Paper is Made: An Overview of Pulping and Papermaking from Woodyard to Finished Product. (Full reference is given at the end of "Papermaking Facts" in this issue.)

"Paper Persists: Why Physical Library Collections Still Matter," by Walt Crawford. Online v. 22, no. 1, 1998, pp. 42-44, 46-48. (On the Web at http://www.onlineinc.com/onlinemag/OL1998/crawford1.html)

Crawford analyzes and rebuts the grandiloquent predictions, common in the early 1990s, of the death of the book and the triumph of the (all-)digital library. His vision for the future is not what you would expect from a "lifelong technologist" who makes his living designing and promulgating services that run on the World Wide Web:

The future means both print and electronic communication.
The future means both linear text and hypertext.
The future means both mediation by librarians and direct access.
The future means both collections and access.
The future means a library that is both edifice and interface.

"Moulds in Paper and Cardboard--Problem of Test Methods," by I. Chadima. Pap. Celul. v. 53, #2, 1998, p. 42-44. (In Czech and English). (PB Abstract 4560, 1998)

Eight different culture media at different pHs were used to test the amount of fungi in paper samples collected from sources with varying degrees of fungal contamination at a paper mill. Petri dishes were incubated under identical conditions for five days. Results demonstrated a need for an international standard for testing of fungal levels in paper, including the way in which samples are taken and the culture medium used.

"Tetrakishydroxymethyl Phosphonium Sulfate (THPS): a New Biocide with Environmental Benefits for Paper Mills," by T.H. Haack et al. 1997 Engineering and Papermakers: Forming Bonds for Better Papermaking, Nashville, TN, 6-9 Oct. 1997, Book 3, p. 1115-1119 (TAPPI Press, 1997). 1557 pp. 3 vols. $141.55 (ISBN 0-89852-706-6) (PB Abstract 4443, 1998)

An entirely new class of antimicrobial chemistry, based on THPS, has been registered with the U.S. Environmental Protection Agency. It can combine broad spectrum antimicrobial efficacy with relatively benign human and environmental toxicity. THPS biocides are classified as nonhazardous, and degrade rapidly on discharge to a molecule that is virtually nontoxic.

"Microbiological Control of Pigments and Fillers in Paper Industry," by J. Mentu et al. Fundamentals of Papermaking Materials--11th Fundamental Research Symposium, Cambridge, UK, 21-26 Sept. 1997, v. 2, p. 955-993. Leatherhead, UK: Pira International, 1997. 1394 pp., 2 vols., £225.00 (ISBN 1-85802-210-X) (PB Abstract 2750, 1998)

Rapid measurement of microbial growth is possible using the Bioscreen C test from Labsystems Oy. This uses an automated turbidometric technique and requires only overnight incubation when used on mineral pigment samples. Measurement of biomass using an adenosine triphosphate assay gave results immediately but was only suitable for high levels of microbial contamination.

"Significantly Reduced Toxicity Approach to Paper Machine Deposit Control," by J.B. Wright. 1997 Engineering and Papermakers: Forming Bonds for Better Papermaking, Nashville, TN, 6-9 Oct. 1997, Book 3, p. 1083-1088 (Atlanta: TAPPI Press, 1997). 1557 pp., 3 vols., $141.55 (ISBN 0-89852-706.-6) (PB Abstract 4439, 1998)

On the inner surfaces of the pipes and vats in the paper machine, bacteria deposit slime as a kind of living environment. When it builds up, production must stop while these deposits are cleared out with "slimicides" and steam. They are a growing problem because of increased closure of mill water systems and use of recycled fiber. a nontoxic control method has been developed, based upon use of a patented surfactant that blocks the assembly of the matrices that hold deposits together.

"Paper Mill Freshwater Treatment: Life After Chlorine. Tips for Selecting Alternative Treatment Programs," by Richard J. Mouché and Robert F. Kelly. Tappi Journal, v. 81, no. 6, June 1998, p. 71-75.

To control microbiological growth in mill water loops, incoming water must be treated. The pros and cons are examined for five chemical alternatives to gaseous chlorine: Sodium hypochlorite (bleach), activated bromine, chlorine dioxide, stabilized bromine and bromochlorodimethylhydantoin (BCDMH).

"Slime and Deposit Control: The Alkaline Challenge," by John Stitt. Pima's Papermaker, Sept. 1997, p. 54-56.

Alkaline papers pose many new deposit control challenges, because of their complex, additive-dependent wet end chemistry; fillers; and the alkaline sizing agents, cationic starch and emulsion polymer retention aids, which provide nutrients for microorganisms and contribute to deposits. Not all the sizing agents stay in the paper; some form slime in which microorganisms can grow. Also, alum, which is used in acid systems to prevent deposits, actually causes more deposits and scale in an alkaline system. The elements of a good deposit control program are described: Wise system design, good housekeeping, and a proper deposit control chemical program.

"The North American Specialty Paper Business: A Market Overview," by Theodore R. Wirtz. Pima's Papermaker Dec. 1997, p. 46-48.

The author has published on the specialty or "technical" paper segment of the industry before this (APA, v. 9 #3, p. 35b), focusing on the types of mills it includes, and offering his advice for business success in the specialty paper market. This article focuses on high dilution technology and the equipment it uses (Rotoformers^TM and inclined wire machines), what can be made with these machines (tea bags, filters, cigar outer wrap, synthetic papers), and which mills use them. (Archival paper and board are produced mainly by what the author calls "semi-commodity" and "semi-specialty" mills.)

The author says that the "specialty papers" market has been a quiet, fairly secretive market segment, and that over the years, industry statistics that would quantify or draw attention to it have been rare. As a result, it is poorly understood by other paper companies, raw material and equipment suppliers or end users of specialty paper grades. He intends to change that picture.

"Heat-Induced Yellowing--A Secondary Phenomenon of Chlorine-free Bleaching ('YELLOW')," by K. Fischer et al. Proceedings of the European Conference on Pulp and Paper Research: The Present and the Future., Stockholm, 9-11 Oct. 1996, p. 83-92. (Brussels, Belgium: European Commission, 1997) 460 pp. ECU 30.00 (ISBN 92-827-9327-3) (PB Abstract 4554, 1998)

Totally chlorine free (TCF) pulps lose a lot of brightness. Yellowing is influenced by temperature, oxidizing or inert media and lignin; it decreases with decreasing lignin content in an oxidizing atmosphere but grows in an inert medium. Heat-induced discoloration is strong when decarboxylation takes place at a temperature of about 100°C. Carbonyl group content is significant in heat-induced yellowing. The pH value is not a dominant factor.

"Coffee Drop Ring, Tideline, Brown Line." (A continuing series of "Classroom Lectures") Progress in Paper Recycling, May 1998, p. 80-84.

This discusses recent research and speculation from the conservation and papermaking fields on the cause of the dark rings that form at the "evaporation front" in paper. But some scientists at the University of Chicago also got interested and published a paper in Nature last year. It is also on their Web site:

Deegan, R.D. et al. "Capillary flow as the cause of ring stains from dried liquid drops." Nature, Oct. 23, 1997. <http://mrsec.uchicago.edu/MRSEC/>>

"Concentration of Metals Entering and Leaving a Recycled

Paper Deinking Mill," by Valerie A. D'Souza, V.C. Hand and R.L. Schaefer. Progress in Paper Recycling, May 1998, p. 22-32.

Metal ions are troublemakers in pulp and paper mills. They can cause deposit problems, brightness reversion, bleach decomposition, and environmental problems. Twelve kinds including iron and copper were measured in paper, process water, effluent and sludge at a 100% recycled paper mill. Most or all of the individual metals entered the mill in the recycled paper and left in the wastewater sludge.

This article is well written and informative. It is an expanded version of the paper "Concentration of Metals in Recycled Papers," presented at the 1998 TAPPI Recycling Symposium, New Orleans, LA, March 8-12, 1998.

"The Role of Transition Metal Ions During Peracetic Acid Bleaching of Chemical Pulps," by Z. Yuan et al. Presented at the 83rd Annual Meeting, Technical Section CPPA, 1997, p. B213-B219.

Peracetic acid (CH₃COOOH) (yes, three O's in a row) is seen as a potential replacement for chlorine-containing chemicals in bleaching of chemical pulps.

Peracetic acid is a strong oxidizing agent, dangerous in contact with organic materials, and it explodes at 110°C. It is widely used in industry as a bleach (textiles, paper, oils etc.), bactericide and fungicide (with foods), catalyst, etc.

Metals have been investigated extensively as a cause of alkaline peroxide decomposition, but not as a cause of peroxy acid decomposition. This study showed that a significant amount of peracetic acid may be wasted when metal ions are present, thus making bleaching less effective. Solution: A chelation pretreatment stage for pulps with high metal ion content (especially manganese).

"Conventional and Stratified Forming of Office Paper Grades," by Ulla M. Haggblom-Ahnger et al. Tappi Journal, v. 81 #5, May 1998, p. 149-158.

All paper, even handmade paper, has a "stratified structure" whether this is intended or not, because the fibers, fines and fillers sort themselves out this way in response to chemical and colloidal forces as the water drains. This paper is a study of the layered structure of uncoated fine paper grades produced by both conventional and stratified forming. The authors say the gap forming technique offers the best opportunities for producing high quality office paper grades, because the paper structure is symmetrical. Multi-layering is a more complicated and expensive technique.

The authors say that "Markets have recently accepted a wider range of raw materials for some offset printing and writing grades. They can contain considerable amounts of 'wood-containing' mechanical or chemimechanical pulp at a maximum level of 10%."

"The Surface and Physical Properties of Toners and Their Effects on Office Waste Deinking," by T.F. Ling. Progress in Paper Recycling, Nov. 1997, p. 50-60.

Toners from copy machines and laser printers are fused to the paper with heat and pressure, and are hard to remove in the deinking process. The composition and characteristics of several types of toners are analyzed for this study of the effect of wettability on the deinking process.

"Binders for Paper Coating: Starches, Proteins and Latices," by N.O. Bergh. Fundamentals of Papermaking Materials--11th Fundamental Research Symposium, Cambridge, UK, 21-26 Sept. 1997, v.1, p. 1139-1209. (Leatherhead, UK: Pira International, 1997) 1394 pp., 2 vols. £225.00 (ISBN 1-85802-209-6) (PB Abstract 2747, 1998)

Starch, proteins and latex are reviewed, as well as the interactions of coating pigment, binder and paper properties. Latex producers can develop polymer dispersions to suit the requirements of various individual paper products within a mill. Different binders may be used together to achieve best performance.

Binders in paper coatings are a concern for paper conservators as well as for papermakers, because books printed on coated paper usually block if they dry out after being dampened or soaked in floods. Conservators have no way of separating pages of blocked books; however, they might be able to find a way if they knew what binders were used.

"Differentiation and Classification of Photocopier Toners: A Comparison Between [DRIFTS, SEM-EDX and PyGC]," by James Brandi, Bruce James and Steven J. Gutowski. International Journal of Forensic Document Examiners, v. 3, #4, Oct./Dec. 1997, p. 324-343.

Seventy-five different toner samples from 10 companies were examined and the analytic techniques evaluated. The combination of SEM-EDX and DRIFTS (Diffuse Reflectance Infrared Fourier Transform Spectroscopy) gave the best discrimination and reproducibility.

"MoDo Wants to Fight the Forgery of its Copy Paper," short anonymous article in Allg. Pap.-Rundsch., no. 1, 5 Jan. 1998, p. 9. (PB Abstract 3014, 1998)

Imitation ("forgery") of successful products is not limited to high-fashion clothing or packaged food sold in the supermarket. Even copy paper gets knocked off, as this example shows. MoDo Paper's DataCopy paper was first forged in 1993 in Turkey and, more recently, in Bulgaria and the Ukraine. Counterfeit paper is analyzed at MoDo's Husum mill in Sweden, where it is tested for quality, whiteness and printability.

"Sustaining the World's Forests," by Janet N. Abramovitz. In State of the World 1998: a Worldwatch Institute Report on Progress Toward a Sustainable Society, p. 21-40. W.W. Norton & Co., New York & London, 1998.

The author says that almost half the forests that once covered the earth are gone, and deforestation is expanding and accelerating. the health and quality of remaining forests are declining. This, briefly, is due to mechanization of forestry and agriculture, globalization and free trade, huge fires, pollution, and greenhouse gases that bring climate change. These trends are driven mainly by increasing population, affluence, and consumption. Governments of developing countries often look to their forests as a standing asset that can be liquidated to solve financial problems.

Watershed protection is lost when forests disappear; floods become frequent and severe; landslides result (94% of the hundreds of landslides that occur yearly in the U.S. Pacific Northwest originate from clear-cuts and logging roads). Transnational logging operations are increasingly involved in these changes. The subsidies for use of public land, even in wealthy countries, can be so large that governments are in effect paying private interests to take public timber.

"The Bleaching of Mechanical Pulps with Oxygen and Borohydride," by G. Leary et al. Holzforschung v. 1, no. 5, 1997, p. 445-451. (PB Abstract 1216, 1998)

Brightness gains of 15 to 20 points were made after bleaching of mechanical pulps by treatment with oxygen gas and an alkali in the presence of borohydrides. The process is not economically competitive with traditional peroxide bleaching, however, owing to the high cost of borohydride.

"Do Zeolites have a Role in Peroxide Bleaching?" by D. Finnegan et al. 51st Appita annual general conference, Melbourne, Australia, 28 Apr.-2 May 1997, v. 2, p. 389-395. (Carlton, Australia: Appita, 1997) 694 pp., 2 vols. ISBN 0-646-31809-8 (PB Abstract 7470, 1997)

Hydrogen peroxide can bleach mechanical pulps without breaking down the lignin, but it decomposes in the presence of metals, which often come mainly from the wood itself. In the reported study, the rate of peroxide decomposition decreased when zeolite-A and sodium citrate were added to pine TMP alkaline peroxide bleaches containing manganese; brightness also increased. The zeolite's ability to chelate metal ions was comparable to that of DTPA when sodium citrate was added.

A paper on a similar study, confirming these results and reporting several others, all beneficial, was given the following month in Montreal by J. Rivard et al. (PB Abstract 7479, 1997).

"The Modified Zeolite in Waste Paper Recycling," by M.M. Sain et al. Presented at the 83rd Annual Meeting, Technical Section CPPA, 1997, p. B195-B199.

A sodium a type zeolite can be impregnated with bleach chemicals, which are later released. The role of zeolite support in fines retention and white water quality is discussed.

Zeolite can be modified and used as an oxidative or reductive catalyst. Used with selected organic acids, it can serve as a stabilizer in the pulp brightening process; and synthetic zeolite has been investigated as a replacement chemical for calcium carbonate and talc in the papermaking process.

"Utilizing Cellulon^® Cellulosic Fiber for Binding in Nonwoven Applications," by Frank J. Miskiel. Tappi Journal v. 81 #3, Mar. 1998, p. 183-186.

Cellulon is a bacterial cellulose made by a strain of Acetobacter in an agitated culture. It is composed of extremely fine (0.1 m in diameter) reticulated fibers with a high surface area. It has a great affinity to water and hydrogen bonds easily, which makes it valuable as a binding agent and retention aid in the forming of paper and polyester nonwovens. When present in fairly small amounts (up to 5%), it increases the tensile index of a dry rayon sheet a thousand times, and a dry Kevlar^® sheet four times. When the sheets were wet, tensile index still improved, but much less.

Monsanto bought the product from Weyerhaeuser in 1995. The particular strain of Acetobacter selected by Weyerhaeuser is unusual, if not unique, in being able to produce cellulose in an agitated solution.

"Mill Experiences with AT Precipitated Calcium Carbonate (PCC) in Papers Containing Mechanical Pulp," by R.L. Ain and M. Laleg. Pulp and Paper Canada, vol. 98, no. 12, Dec. 1998, p. 172-176. (PB Abstract 3549, 1998)

Acid-tolerant PCC, developed for use with mechanical pulps, overcomes the problems of pulp darkening at alkaline pH and the dissolution of PCC at an acid pH. In newsprint trials, it stabilized the paper machine pH at neutral and kept dissolved calcium levels low. It improves brightness and opacity. Papers made with AT PCC age significantly better than acid papers: strength and brightness losses were significantly lower, and no pitch or deposit problems developed.

"Inhibition of the Dissolution of Papermaking Grade Precipitated Calcium Carbonate Filler," by Peter Pang, K.K. Khoultchaev and P. Englezos. Tappi Journal April 1998, v. 81 #4, p. 188-192.

Sodium oxylate and phosphoric acid were used to inhibit dissolution of PCC so that it could be used in the acid range, where alkaline conditions will not darken mechanical pulp. Because wastewater treatment would also benefit from a method to keep calcium carbonate from dissolving in acid water, researchers in that field identified several chemicals that could help: Magnesium ions, ions of 1,2-dicarboxylic acids, oxalate ions, and orthophosphate. Phosphoric acid worked best. Inhibition is thought to be made possible by formation of a layer of insoluble calcium compounds on the surface of the calcium carbonate particles.

"Value-Added Groundwood Grades Offer Alternative for Heatset Offset Printing," by Charles P. Klass. Pulp & Paper, March 1998, p. 71-77.

Groundwood grades range in quality from newsprint at the low end, to lightweight coated (LWC) at the high end. LWC is freer of problems on the press than other grades but it is expensive because it needs a high proportion of kraft pulp in the furnish. Fortunately, a new machine has made it possible to coat high groundwood sheets: the metering size press. A high gloss can be given these papers with soft nip calendering.

The reason North American newsprint was unfilled until about 20 years ago was that the customs classification specified a maximum of 3% ash content. Then offset began to replace letterpress in the printing of newspapers, and (as always happens) paper evolved to meet the needs of the preferred printing method. Surface strength and resistance to linting increased; with USA Today's debut, color and filler use increased. To make a long story short, new surface-treated grades have been created to meet the need (surface-treated newsprint and supercalendered papers; machine-finished pigmented; machine-finished coated; and film-coated offset), and machines have been adapted to make the new higher-quality groundwood grades.

"A Snapshot of the Current State of Cluster Compliance for Kraft Mills," by Steve S. Dowe. Tappi Journal, April 1998, v. 81 #4, p. 82-84.

The first of EPA's Cluster Rules for air and water effluent regulation are now being enforced. They permit elemental chlorine free (ECF) bleaching, as long as certain criteria are met. (For details see Bill Nichols' "Four Years of Work, Debate Produce First Phase of EPA's Cluster Rules," in Pulp & Paper, Jan. 1998, p. 71-78.)

The author surveyed 124 kraft mills, 86 of which bleached their pulp. One of the 86 was totally chlorine free, one was considering closing their operation, and one has shut down its bleaching operation. Fifty-five were able to bleach with ClO₂ and meet their product quality criteria. The other 28 must increase their ClO₂ production capacity, add oxygen delignification or another ECF bleach process, or change to a TCF process.

"Alternatives to Landfill/Landspread," by M. Hillman. Managing Environmental Effects: PITA Environmental Seminar, Chorley, UK, 13 May, 1997, 4 pp. (PB Abstract 1489, 1998)

The projected size and cost of paper mill sludge disposal over the next 8 years, as landfill costs increase, is given together with an overview of the range of sludges, their key properties and criteria for added value products. Paper mills are advised that substantial investment costs will be needed in order to find cost-efficient alternative uses for sludge when landfill is no longer an option.

"Potential Use of White Rot Fungi to Decontaminate Polluted Soils," by J-C. Sigoillot, C. Mougin and L. Sohier. Biofutur #170, Sept. 1997, p. 34-36. (In French) (PB Abstract 1511, 1998)

Soils contaminated with organic pollutants can be cleaned up with the aid of white rot fungi, which can break down lignin and grow in hostile environments, unlike bacteria cultivated in vitro. The most appropriate fungus must be selected for each contaminated site. When gases are forced through the contaminated soil to promote the growth of fungi, contaminants can be reduced by almost 50% in 28 days.

"Paper Mill Sludge: Feedstock for Tomorrow," by Jim Glenn. Progress in Paper Recycling, May 1998, p. 54-59. (Reprinted in modified form, with permission of BioCycle, from the Nov. 1997 issue of Biocycle, Journal of Composting & Recycling, v. 38, no. 11, p. 23-30.)

In the 16 years between 1979 and 1995, the percentage of sludge going to landfill or a lagoon declined from 86% to 50%; incineration more than doubled; and land application sextupled. Beneficial use and recycling/reusing are coming to be more important, but accounted for no more than 7% and 6% of disposal methods used in 1995, according to a survey of NCASI members (ncasi=National Council of the Paper Industry for Air and Stream Improvement). This article describes how member mills handle their sludge.

History of Paper Inventor Tsai-Lun, by Y.K. Yung. Part one is in Chinese (72 pp. with 75 illustrations); Part two is in English, with excellent portraits, a biography of Tsai-Lun, dates of the spread of papermaking, and an article reprinted from IPH-Information, 1983, no. 3. Published by the author, 769 Xia Tu Road, Shanghai 200023, P.R. China. Price per volume is $30, postage paid; for IPH members, $24. (IPH-Information is the newsletter of the International Association of Paper Historians.

"Museum Pieces," by A. Jankovic. Pap. Eur., vol. 9, no. 4, July 1997, p. 39. (PB Abstract 7908, 1997)

This article describes the paper artifacts in Papierfabrik Scheufelen's Museum of Paper and Book Art, near Lenningen, Germany. Adolf Scheufelen developed a [presumably automated] process in 1892 for coating paper with kaolin and casein. Art paper was also developed in 1892. Although paper had been coated using a hand-held brush for centuries, these two inventions made widely available the paper needed for printing of high-quality half-tones.