文档介绍：UNIT TWO
PACKAGING MATERIALS AND CONTAINER
第二单元包装材料和容器
Lesson 3
Paper and Paperboard
第3课纸与纸板
Introduction
Definition of paper:
·Paper is defined as a matted or felted sheet usually
composed of plant fiber. Paper has mercially
made from such fiber sources as rags (linen), bagasse
(sugar cane), cotton, and straw. Modern paper is made
almost exclusively from cellulose fiber derived from wood.
·Although the word “paper” is derived from the Egyptian
term, “papyrus” was not a true paper in the modern
sense.
- Invention of paper
·The invention of paper by blending cellulose fibers didn’t
occur until the beginning of the second century .
Introduction
Ts’ai Lun, a member of the court of the later Han
Dynasty, is generally credited with developing the first
real papermaking process in 105 .
·The “Fourdrinier machine” was the first on the market
and produced a homogenous (single-ply) sheet of
boxboard in various thicknesses. It was soon joined by
the “Cylinder machine” which formed a multi-layered
(multi-ply) type of paperboard. These machines were first
installed in the United States around 1830.
Introduction
Paper and paperboard
· Paperboard, boxboard, cardboard, and cartonboard are all terms used to describe heavier paper stock.
· The anization for Standardization (ISO) states that material weighing more than 250 grams per square metre (511b per 1,000 sq. ft.) shall be known as paperboard. . practice calls material that is
more than 300( in.) thick paperboard.
Representative Papermaking Machines
Fourdrinier Machines
Fourdrinier machines (Figure ) pump furnish from a
headbox directly onto a moving wire screen through
which the water is continuously drained. Fourdrinier
machines may have a second headbox (Figure
)situated downstream of the first headbox to add
further quantities of furnish onto the partially dewatered
initial lay-down.
Representative Papermaking Machines
Figure Furnish pours out of the headbox o