Literature

"Troubleshooting Alkaline Paper Problems," by Lane Olinghouse. Instant & Small Commercial Printer, Nov. 1994, p. 39. Today's sticky lithographic inks tend to pull carbonate filler particles out of the paper, which may have been weakened through the moisture (fountain solution) applied to its surface. The carbonate particles become absorbed in the ink on the rollers; if the quantity is great, they may prematurely activate the ink's drier, causing a hardened glaze to form on the rollers and blanket. Solutions offered: 1) Switch to low-tack inks; 2) use one of the newer lithographic inks that are impervious to the alkaline influence; 3) do frequent washups; 4) use a low-acid fountain solution; and 5) run minimum amounts of ink and water. (3A9.31)

"Causes and Prevention of Deterioration in Book Materials," compiled by Robert P. Walton. New York Public Library, 1929. This is a 39-page indexed bibliography on paper and leather (in separate sections), originally published in the Bulletin of the New York Public Library, April 1929. Entries are dated 60 AD (Pliny the Younger's comments on papyrus) to 1929, and are arranged in date order. The abstracts and commentaries are long and informative. About half of the references are from the library literature, and the rest from the paper industry or government.

Unlike most bibliographies, this one makes pretty good reading. In 1891, when wood pulp had not been in use much more than 20 years, a librarian named Rossiter Johnson wrote the article "Inferior Paper a Menace to the Permanency of Literature," and predicted that "centuries hence some bibliographer will construct an ingenious theory to explain why no books were printed between 1870 and 19--, the date at which we accomplish the destruction of the forests and begin again on cotton." That same decade, the Society of Arts, in England, published its investigation of the deterioration of paper, the summary of which here takes up most of a page in fine print. (3B1.1)

Photochemistry of Lignocellulosic Materials. American Chemical Society, 1993, 232 pp. $64.95. Available from ACS Distribution Office, Dept. 319, PO Box 57136, West End Station, Washington, DC 20037. This concerns light-induced yellowing of lignin-containing paper, techniques of observation and research on controlling it. (3B1.4)

"The Switch to Alkaline Paper," by Lane Olinghouse. Instant & Small Commercial Printer, Oct. 1994, p. 41. This piece is in a column called "Operations," and is part of a series on alkaline paper, a welcome and long overdue explanation of this new material that quick printers have been struggling with on their own for the last few years. The writer is an experienced, well-informed printer who believes the advantages of alkaline paper outweigh its disadvantages, and apparently knows how to use it. One point that he misses is the pH of calcium carbonate-filled paper. PCC-filled paper may come off the paper machine at pH 7.5 to 8.0, but the pH then rises, and is often in the 9-10 range by the time the printer gets it. This is not widely recognized. (3B3.42)

"Fractionation of Secondary Fiber--A Review," by Gary M. Scott and Said Abubakr. Progress in Paper Recycling, May 1994, p. 50-59. 102 references.

Both authors are at the Forest Products Lab in Madison. They review the literature of fiber fractionation, a process that has gained significance as a result of the increasing use of waste paper for making paper of all sorts. It allows the short, low-quality fibers to be separated out from the good long fibers, so that each can be processed with the most suitable equipment, and then recombined in desired proportions for different types of paper. (3B3.6)

"Opportunities for Composites from Recycled Wastewood-based Resources: A Problem Analysis and Research Plan," by Roger M. Rowell and ten other authors from a variety of companies, agencies and institutions. Forest Products Journal 43/1, Jan. 1993, p. 55-63.

The abstract says, "There are many opportunities to produce composites from recycled biobased fiber. The fiber can be used alone to make low-cost and high-performance composites, combined with inorganic materials, or combined with other recycled materials, such as plastics, to produce mixtures, compatibilized blends, and alloys. This report describes the resources available; problems associated with collecting, sorting, cleaning, breakdown, classification, and blending of the recycled resources; and process considerations for forming vrious types of composites. We propose a framework for research to utilize biobased resources in the waste stream. . . ."

Types of waste considered as raw materials for these composites include waste paper, as well as metal, glass and plastic, but methods of using waste paper in composites are still largely undeveloped. (3B3.6)

"Toilet Paper from Recycled Paper can be Dangerous to Health." Anon. Allg. Pap.-Rundsch. 117/42, 20 Oct. 1993, p. 1061 (In German). Skin specialists at the University of Munich have discovered that substances in waste paper used in toilet paper can produce contact allergies and other effects. There can be 10 to 100 times more metal present than in virgin pulp. The dermatologists recommend that toilet paper should not be made from recycled paper. (PBA Abstract 1675, 1994) (3B3.6)

Wet-strength resins have had a lot of attention lately. The first news item in the October APA was about a "durable-press" process (using polycarboxylic acids and catalysts) that also serves as a wet-strength process for paper. The same or a similar process was described by Phil Luner et al. at the September 1993 meeting at Oxford, Products of Papermaking--Tenth Fundamental Research Symposium. Other compounds that work are described in PBA Abstract # 4137 (1994).

TAPPI Press has published a book by the Papermaking Additives Committee of the Paper and Board Manufacture Division, Wet Strength Resins and Their Application. This is an update of the 1965 edition. It has 136 pages and costs $49 for members, $73 others.

An article potentially very useful for waste paper dealers and brokers is "Secondary Fiber Processing: Laboratory Evaluation--Wet Strength Paper Repulping," by C. Njaa, A. Renders and P. Walsh, Progress in Paper Recycling, Nov. 1994, p. 26-31. This is not about how to use wet strength resins in papermaking, but about how to tell what kind of resin is in the waste paper to be repulped, because some of them dissolve under normal conditions and others don't. The permanent wet-strength resins (urea and melamine-formaldehyde, and PAE or polyaminoamide epichlorohydrin) can only be dissolved in hot water. The formaldehyde compounds require a pH under 4.0 and the PAE requires the use of NaOH. A spot test is described for distinguishing the two resins. (3B3.61)

"Paper Grade Classifications," Technical Information Sheet 0404-36, issued 1987 by TAPPI. Over 300 specific grades or end-uses are listed in a table that indicates the major kind of paper commonly used for each grade. Computer paper, for instance, may be made of coated or uncoated groundwood or wood free paper, while copy paper is usually made only from uncoated wood free paper.

A classification like this, which lists both the end use and the paper stock used, may be the most practical kind, because neither dimension (use or material) is sufficient by itself.

TAPPI may not be able to send a copy, because this series of information sheets is not being kept up. (3B3.71)

"Can Kraft Mills be Potassium-Based?" by Tom Grace. PIMA Magazine, June 1994, p. 82-83.

Sodium-based chemicals are used in kraft mills for historical reasons: sodium sulfide and sodium hydroxide were cheap at the time the soda process (predecessor of kraft) was invented. Now the cost of sodium hydroxide, or caustic soda, is escalating. [This is understandable, since sales of chlorine are falling, and bleach and caustic are co-produced from salt brine, the Na going into caustic and the Cl going into the bleach. It is not economic to run the process and get only one product from it.]

The author says that limited lab studies show that kraft and soda pulps can be produced effectively (and maybe even better and faster) using potassium sulfide and/or potassium hydroxide. They could also ameliorate the problem of potassium buildup in the recovery boiler, a growing problem. Potassium comes into the mill in the wood chips, reacts with other chemicals and is hard to remove from the process. (3B3.8)

"Bleaching Processes for the Production of Mechanical and Chemi-mechanical Pulps of High Brightness," by S. Dessureault et al. Pulp & Paper Canada 95 no. 7, July 1994, p. 18-26.

The authors looked for the process that gave the brightest pulp at the cheapest price, with the least color reversion after thermal treatment, and settled on a double-stage bleaching sequence: peroxide at high consistency in the first stage and hydrosulphite at medium consistency in the second, or PY for short. This gave pulps in the 79-85% ISO brightness range, which after thermal treatment (heat aging) at 60°-70°C for 60-90 minutes declined only 1.5-2.0% points--pretty good for this kind of pulp. [However, that thermal treatment is quite mild when compared with the accelerated aging conditions used to test for paper permanence: 80°-90°C and 50-65% RH, for 1-4 weeks or longer.] (3B3.83)

"Bleaching of Secondary Fibers--Basic Principles," by Dominique Lachenal. Progress in Paper Recycling, Nov. 1994, p. 37-41. Ozone, chlorine dioxide and sodium hypochlorite work on chemical pulp, and nondegrading chemicals such as hydrogen peroxide, FAS or sodium dithionite work on pulps with over 20% mechanical fiber. No single bleaching compound works well for both mechanical and freesheet fiber. (3B3.83)

"Activated Oxygen for Totally-Chlorine-Free Bleaching of SW Kraft Pulps," by K. Hung, C.-L. Lee and R.W. Murray. A paper presented at Pacific Paper Expo 1993, held at Vancouver, Canada, Nov. 1993; p. 21-25 in the preprints or proceedings. Dimethyldioxiranes are a new group of potential non-chlorine bleaching compounds in the family of activated oxygens which react with lignin much as chlorine does and substantially enhance Kappa number reduction. (PBA Abstract 4103, 1994) (3B3.83)

"Board Mill Conversion to Alkaline Process," by D. Janigan, C. Cossette, and L.-G. Angell. Pulp & Paper Canada 95/10 (1994), pages T 407-T 411.

News of successful alkaline conversions in mills using mechanical pulps has travelled over the grapevine for the last few years, but no one expected them to publish descriptions of how they did it until they had the process under control. (Making groundwood grades at a high pH has been technically impossible until recently.) This paper is about Kruger Inc.'s mill in Montreal, where they have been making alkaline multi-ply linerboard and wrapper since 1989. The outer layers are white, and may contain up to 10% calcium carbonate filler.

This mill is one of those that converted in self-defense, because the waste paper stock they were buying contained calcium carbonate filler, which interfered with the chemistry of the acid system they had, causing foaming and deposits. When the decision was made to go alkaline, they had already heard of other mills like theirs that were operating in an alkaline medium. (3B3.85)

Eco-Sanity: A Common-Sense Guide to Environmentalism, by Joseph L. Bast, Peter J. Hill and Richard C. Rue. Madison Books UPA, 1994, 316 p., hardcover, $22.95. This book was listed in Science News for October 1, and can be ordered from SN on Visa or MasterCard, by calling 800/544-4565; add $2 for postage. The blurb says, "Urging a change in the alarmist strategies of many environmentalists, this treatise provides a 40-point plan for an efficient, practical means of advancing the environmental agenda. Many pages are devoted to the progress of the movement. However, as reported here, the backlash to 'green at any cost' has arrived, requiring a new focus for maintaining environmental prosperity." (3B3.93)