包装材料专业英语

第5、6讲

Unit 3 Packaging Materials and Containers

（第三单元包装材料和容器）

Lesson 1 Paper and Paperboard（第1课纸与纸板）

（概述，典型造纸机，纸板的加工方向与横向，表面处理与涂覆，纸特性，纸/纸板等级，纸盒）

1. Introduction (概述)

Definition of paper: paper is defined as a matted or felted sheet usually composed of plant fiber. Paper has been commercially 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: t he invention of paper by blending cellulose fibers didn’t occur until the beginning of the second century A.D. 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 A.D.

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 m achine” which formed a multi-layered (multi-ply) type of paperboard. These machines were first installed in the United States around 1830.

·Paperboard, boxboard, cardboard, and carton board are all terms used to describe heavier paper stock. The International Organization 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. U.S. practice calls material that is more than 0.3mm(0.012 in.) thick paperboard.

2. Representative Papermaking Machines (典型造纸机)

(1)Fourdrinier Machines

Fourdrinier machines (Figure 3.1) 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 3.2)situated downstream of the first headbox to add further quantities of furnish onto the partially dewatered initial lay-down.

Figure 3.1 Furnish pours out of the headbox of a fourdrinier machine and onto an endless wire or screen where excess water can be drained. The fibers remain trapped on the screen

Figure 3.2 Paper is dewatered at the wet end of a fourdrinier machine

(2)Cylinder Machines

A cylinder machine (Figure 3.3) rotates a screen drum in a vat of furnish (The paper is sometimes called vat paper). As the water pours through the screen, fiber accumulates on the outside of the screen. This thin layer of matted fiber is transferred onto a moving felt belt that passes sequentially over further rotating cylinders, each of which deposits another fiber layer.