Volume 4, Number 2
May 1991

Letters

To the Editor:

The article by Herb Espy ["The Genesis of Alkaline Sizing and Alkaline-Curing Wet-Strength Resins," APA, Aug. 1990, p. 28-291 is historically correct. The article by J. W. Davis, W.H. Roberson and C.A. Weisgerber was one of the first and best presentations on alkaline sizing made to TAPPI on February 3, 1955.

During the early days of alkyl ketene dimer sizing before the advent of starch stabilized emulsions, I was involved with numerous trials of AKD in several forms, namely Aquapel 364, a dry waxy flake mainly consisting of higher melting point fatty acids such as stearic and palmitic; Aquapel 380, a dry emulsifiable product composed of a mixture of high and low melting point fatty acids plus a nonionic surfactant; Aquapel 421, a low efficiency liquid made using oleic acid to form the acid chloride; and last but not least, Aquapel 486, a dry silica powder which was surface treated with Aquapel 364. Trials of these products were nightmarish, to say the least. Aquapel 380 was used via spray booms and although sizing was often obtained, dryer picking and slippery rolls were almost impossible to deal with. Aquapel 380 was added as a dry flake to the machine chest and one prayed that it would be retained in the system to melt an the dryers and react with the cellulosic hydroxyl groups. Often it was not, with the result that off-machine sizing was zero. So much material had to be added that to obtain the sizing required, the cost tended to be prohibitive. Aquapel 486 was added to the dump or machine chest, an unscientific procedure. We tended to coat the top of the chest, the floor and nearby equipment with silica dust, creating a hazardous slippery condition.

I remember running a trial of Aquapel 486 in a cylinder board application at the old Hinde & Dauch paperboard mill in Toronto, Canada, in 1956. The alkaline was on rosin size and alum. After both of these products were removed and the pH raised with caustic soda to 7.0-8.0, Aquapel 486 was added to the machine chest. We retained no sizing whatsoever and lost vat levels. Our knowledge of sizing systems, based on experience with rosin, was no use to us. (Because a rosin size system is foamy in nature, it allows the entrapment of air, thus reducing the drainage on the cylinder molds so that the paper mill is able to keep its vats at efficient operating levels.) After two hours we were escorted from the mill and it was suggested that we not return.

The breakthrough in this whole technology was definitely the discovery that you could emulsify Aquapel 364 with a cationic starch. This work was done by Bob Tofte, who worked for Charlie on the West Coast, I believe in the lab at Fiberboard Corporation in Antioch, California.

Your old-timers list [see the Hercules part of this list below. -Ed.] is fairly complete but should include Bill Roberson, Don Thompson, Woody Rice, Ozzie Kincannon and Jack Keough, all Hercules personnel who personally spent a great deal of time introducing alkaline sizing to a reluctant industry.

I had the dubious task of being the Aquapel Product Manager during the years of 1966-69. My mission was to convert the printing and writing industry from acid to alkaline sizing. Once you told the papermaker to remove alum from the system, the guarantee of failure was engraved in stone. Alum was, and still is in a lot of cases, the papermaker's ally, and the papermaker could not make paper without it. As you know, in the early days, alum was detrimental to the development of sizing with alkyl ketene dimer and we absolutely insisted on having it removed from the system although, as you know, today it is often part of the sizing package-both with AKD and ASA.

This particular period, 1966-1969, was most interesting, as we developed a great deal of technical information involving the behavior of other chemicals such as fillers, dyes, retention aids, pitch dispersants, wet strength resins, biocides, etc., under alkaline conditions. The only major supplier of precipitated calcium carbonate for wet end addition that we were ware of was Wyandotte. Ground calcium carbonate did not give very good optical properties.

This also was an era of tremendous cooperation with various other companies such as DuPont, National Starch, A.E. Staley and J.M. Huber Company, to name a few. Everyone recognized and sensed that a new era was developing and that alkaline paper someday would be a reality. Many hurdles would have to be overcome, especially the papermakers' reluctance to even carry out an evaluation, as they were in completely uncharted waters when running at alkaline pHs. Fillers could not be retained, foam was a problem, slime and bacteria had to be controlled with new bactericides, felt and wire filling and dryer deposits were common, excessive pick-up at the size press was a serious problem due to a waterleaf sheet, and of course, there was SLIP. It was not uncommon for an MG grade of paper to leave the Yankee and continue on upward into the hood, wrapping the exhaust fan. Other horror stories could be told, such as keeping a roll of board an the reel and then having the reel telescope once it was removed when the tow motor driver tried to stand the roll on its end. We were a very popular group at that time, I can tell you!

Chandler Associates, a specialty chemical technology transfer company, is heavily involved in the alkaline papermaking field at the present time. We have clients around the world who are just now becoming interested in alkaline sizing and we are working with them starting from scratch. It is easier today, as half of the world is an alkaline sizing " most of the problems have been addressed and solved. One of the big secrets of success of alkaline sizing, incidentally, is when a directive is issued by the Chairman of the Board that his mill will go alkaline. it's amazing what cooperation you get from the paper alkaline superintendent and operating crews. As you know, several major companies have switched from acid to alkaline conditions in one month, something that would be almost unheard of in the 1950s, 60s and even 70s.

Incidentally, I forgot to mention that during my role as product manager, I was only able to convert one major fine paper mill to alkaline sizing in the U.S. and Canada. I worked very closely with one well-known company, namely, P.H. Glatfelter, of Spring Grove, Pennsylvania, and its R&D manager, Bob Olson, whom you mention in your old-timers list. P.H. Glatfelter went alkaline but, unfortunately for Hercules, with a competitive process, which was successful at Glatfelter mainly due to better response of ASA for sizing development.

[The old-timers list has more Hercules people on it than people from any other company: 17. They are Paul Aldrich, Bob Cates, Charles Chapman, Jim Davis (deceased), Bob Davison, Clarence Hanford, Gerald Keim, Jack Keough, Ozzie Kincannon, Bob Leahy, Ed Meginniss, Woody Rice, Bill Roberson, David A. Smith, W. Don Thompson (deceased), Bob Tofte, and Cy Weisgerber. The list is still growing. Not everyone on it was directly involved during the momentous 1950s, but judging from those contacted so far, everyone who is still around has a story to tell. -Ed.]