|
|
Gum is a compound in a liquid or semi-liquid state that adheres or bonds items together. Gum may come from either natural or synthetic sources. Some modern types of gum are extremely strong, and are becoming increasingly important in modern construction and industry. The types of materials that can be bonded using gum are virtually limitless, but they are especially useful for bonding thin materials. The first adhesives were natural gums and other plant resins or saps. It was believed that the sumerian people were the first to use them until it was discovered that neanderthals as far back as 80,000 years made adhesives from birch bark.Natural gum is made from inorganic mineral sources, or biological sources such as vegetable matter, starch, and natural resins or from animals e.G. Casein or animal glue. They are often referred to as bio-adhesives. Animal gum is traditionally used in bookbinding, wood joining, and many other areas but now is largely replaced by synthetic gum. Other form of natural adhesives is blood albumen (made from protein component of blood) and is used in plywood industry. Elastomers, thermoplastics, emulsion, and thermosetting adhesives are examples of synthetic gum. Glue sticks are solid adhesives in twist or push-up tubes. The user can apply glue by holding the open tube, thus keeping their fingers clean. Glue sticks are only designed to glue paper, card and felt together, as glue sticks are not as strong as some liquid based variants. They can be used for craft and design, office use and at school. Because of their ease of use, and their economic value, glue sticks are a popular school and office supply.
|
|
|
|
|
