Papers and Boards

1 Key terms

Paper is a thin material produced by pressing together moist fibres of cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets. It is a versatile material with many uses, including writing, printing, packaging, cleaning, and a number of industrial and construction processes.
In Europe, paper and board is measured in grams per square metre (gsm).
This means the number of grams a 1m X 1m sheet weighs 80-220gsm.
There is a suggestion that the thicker the paper, the better the quality.
Standard copier paper is usualy 80gsm. with typical writing paper being 120gsm.

Weight - 80gsm.
Description - Thin, lightweight, cheap, bright white paper, with a smooth, bleached, uncoated surface.
Uses - Writing, printing and drawing.
Advantages - Takes colour well, good surface for pencils, pens and markers, cheap, readily available and in a range of colours.
Disadvantages - Can be prone to jamming printer feed mechanisims.

Weight - 120-150gsm.
Description - Creamy, thick heavyweight paper.
Uses - General drawing and printing, can be used with watercolour paints without buckling.
Advantages - Accepts most drawing media, opaque.
Disadvantages - Costs more than copier paper.

Weight - 60-90gsm.
Description - Thin, smooth and translucent, made by beating to remove air and processing to make a dense, strong paper.
Uses - Art, making copies, envelop windows and overlays on working drawings.
Advantages - Strong, translucent.
Disadvantages - Can be expensive, limited ink absorption and longer drying time.

Paperboard is a thick paper-based material. While there is no rigid differentiation between paper and paperboard, paperboard is generally thicker (usually over 0.30 mm, 0.012 in, or 12 points) than paper.
According to ISO standards, paperboard is a paper with a grammage above 250 g/m2, but there are exceptions.
Paperboard can be single- or multi-ply. Paperboard can be easily cut and formed, is lightweight, and because it is strong, is used in packaging.
Another end-use would be graphic printing, such as book and magazine covers or postcards. Sometimes it is referred to as cardboard, which is a generic, lay term used to refer to any heavy paper pulp–based board.
Paperboard is also used in fine arts for creating sculptures.

Description - Stiff layers consisting of:
1. A printable bleached virgin pulp top surface.
2. Unbleached yellowish centre layers.
3. A bleached inside layer.
Uses - Cereal boxes, food and health packaging and cartons.
Advantages -
1. Excellent for scoring and bending without splitting.
2. Accepts print well.
3. Inexpensive.
Disadvantages -
1. Lower strength than solid white board.

Description -
1. Two or more layers of fluted paper sandwiched between to paper liners.
2. Available in different thicknesses.
3. Strong and lightweight.
Uses - Protective packaging, for example boxes for electrical products and CD sleeves.
Advantages - Impact resistant, inexpensive, recyclable.
Disadvantages -
1. Brown finish does not convey quality.
2. Can deform under pressure.
3. Not water resistant.

Description -
1. Strong, rigid board made from pure, bleached wood pulp.
2. Excellent printing surface.
Uses - Book covers, food, cosmetics and medicine packaging.
Advantages - Strong, rigid and accepts print well.
Disadvantages - Can be expensive.

Amount of material bends when a force is applied (stiffness), determined by its thickness and weight.
Flexural stiffness is resistance to an external bending force.
Handling stiffness is the ability to support its own weight.

Ability to accept a printed image onto its surface (porosity).
Affected by surface properties, such as smoothness or finish, and structural properties, such as bulk or thickness.
Not the same as print quality, which is determined by other factors such as alignment of plates on the machinery.

Ability to be broken down by bacteria or other biological means.
Most uncoated paper products are biodegradable because they are made from wood pulp.
Compostable means that a material can biodegrade in less than 12 weeks.

Paper and card are extremely useful materials that are processed from wood fibres. They come in many different sizes and forms.
1. How many paper products have you used today?
2. Why do you think that some boards are laminated with other materials, such as foil.
3. How many different paper sizes do you know (list 3).

The box in the image above is used to package CDs sent to a supermarket.
1. Explain one reason why this material is suitable for the box. (2)
2. Explain one disadvantage of this material. (2)
Name three different paper types.
State an advantage of using folding boxboard.
Explain why printing might affect the quality of a finished product?
Describe and compare the properties of two different boards. Evaluate which one would be best for a new perfume package?