CUK Paperboard (Coated Unbleached Kraft)
CUK paperboard is not bleached, which gives the sheet a draft/brown appearance all the way through the sheet. The sheet
may be clay coated or uncoated. CUK is composed of "virgin" fiber, making it the strongest of the paperboards, but not the
smoothest printing surface. CUK paperboard is two or three ply and can be treated with a moisture barrier to render it useful
for beverage carriers.
SBS Paperboard (Solid Bleached Sulfate)
SBS paperboard is bleached, which gives the sheet a clean, white appearance all the way through. The bleaching process
degrades and weakens the "virgin" fibers, which, in turn, has some effect on the strength of the sheet. The clay coating on
the SBS sheet provides a smoother printer surface than CUK or recycled fibers, because bleached fibers are smooth, clean
and pliable. SBS paperboard is usually one ply.
Recycled Paperboards
Recycled paperboards are made from pre- and post-consumer waste. Pre consumer waste is mill conversion waste -
in other words, paper products that haven't made it to market. Post consumer waste consists of paper products that have
been used and discarded. Recycled paperboard is six to nine ply, and has a less desirable printing surface than SBS.
There are four basic grades of recycled papers:
CCNB (Clay Coated News Back)
- Brown or gray (depending on the fiber used)
- Clay coated (one side)
CCLB (Clay Coated Light Back)
- Light gray
- Clay coated (one side)
CCKB (Clay Coated Kraft Back)
- Brown
- Clay coated (one side)
BC (Bending Chip)
- Brown
- Not coated
Caliper
The thickness of a sheet of paperboard is measured in
thousandths of an inch, commonly referred to as "points."
Our paperboard ranges from .012 thickness or "caliper"
to .028.
Paperboard has a "grain direction," which is the direction
that the paperboard is machined at the mill. Cross
direction is 90 degrees to the grain direction.
Paperboard and the Environment
The SBS/CUK mills rely on trees (wood) to produce their products, which is why they concentrate on replanting and
cultivating forests.
Contrary to what many may believe, America's forests are not in decline. They are growing, largely because of replanting
by private landowners, forest products companies (peppermills) and individual tree farmers. America has more trees today
than it did 70 years ago -- there are approximately 230 billion trees in the U.S., or 1,000 trees for every man, woman and
child in the country.
Recycled mills would not exist if the "virgin" mills did not produce paper, because they rely on pre- and post consumer waste.
Four times more paper is diverted from the waste stream for recycling than all other recyclables combined. For every ton of
paper recycled, we save 3.3 cubic yards of landfill. Recycled mills use 64% less energy, 58% less water, produce 74% less
air pollution and 35% less water pollution than "virgin" papermaking.
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