Is it coated or is it supercalendered? Only the paper mill knows for sure.
We keep getting reports of SCA papers being made on coated machines, along with suspicions that the papers are actually coated rather than supercalendered.
Reel Time Report surfaced the issue earlier this month by reporting claims that Verso’s new Clarity SCA+, which is being made on a lightweight-coated (LWC) machine, was actually a coated sheet.
“Producing an SC-A+ grade is not an easy thing to do. It seems nearly impossible on a machine designed to produce coated groundwood,” said the newsletter, which is available by subscription from Forestweb by contacting firstname.lastname@example.org. “The more logical path, from a production-cost perspective, is to simply produce coated groundwood and label it SC-A — maybe bleach the grade a little less, perhaps change the coating formulation some — but the fewer changes the better. That seems to be what Verso is doing.”
My sources tell me that Verso insists it is using proprietary technology to make SCA+ and SCA on a coated-paper machine, but at least one competitor insists that the SCA+ is actually coated. Some sources agree with Reel Time Report in questioning whether SCA+ and LWC can be made on the same machine, but one source notes that the Clarity line has the crackly sound of a supercalendered paper.
Verso has muddied the waters by making SCA on both the LWC machine and the supercalendered machines at the same mill in Sartell, MN. Both are called Clarity SCA, but the specs are different depending upon the machine. Between those differences and tweaks to the new product, printers are having fits trying to evaluate runnability and ink consumption on Clarity SCA, which many customers are eager to use because of its aggressive pricing, sources say.
Sources also tell me that AbitibiBowater has shifted some production of SCA from idled Canadian mills to its coated mill in Catawba, SC. That makes sense given the mill’s low-cost position, the strength of the Canadian dollar, and the black-liquor subsidy of American-made kraft pulp. But again it raises questions about whether the paper is really an SCA or just lightly coated.
We’re also getting reports of an SC sheet coming out of Myllykoski’s Alsip, IL, which only has a coated machine. That may stem from confusion with Myllykoski’s SC mills in the U.S. and Europe. But Myllykoski has been more reluctant than most competitors to take downtime at Alsip during this weak market, so perhaps that mill is producing some grades that are not on the official list of its products.
Catalyst Paper has also toyed with making a paper for the SCA market on its Port Alberni, BC LWC machine but has clearly told customers that the paper is coated. Sources indicate the future of that product is uncertain.
Some people would argue that none of this matters, that the issue is not how the paper is made but rather how it performs. Don’t tell that to the printers. Even the best SCA+ papers consume more ink than LWC and need different tension settings on the web. Because clay and other materials that provide gloss are embedded in the sheet rather than on the surface, as with coated paper, SC papers tend to have less surface strength and are therefore less tolerant of high-tack inks.
What is clear is that North American paper mills are battling overcapacity by using their coated paper machines to make an increasingly wide variety of uncoated papers.
See also The Rush to Make Uncoated Paper on Coated Machines.