Professional Polymer Technology
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Plants and Animals can provide us with Polyurethane Glu […]
Plants and Animals can provide us with Polyurethane Glue. Glues are used in a multitude of applications. The uses are in pest control where glue is used to trap rodents and flying insects. Just as some plants have used glue to trap insects, so we are doing so today and with great effect.
PUR (Poly Urethane Reactive) Glue is a type of adhesive used by book binding experts which lasts longer than the hot melted and the cold emulsion glues. It is clear and withstands any temperature. Only a little is needed for a good bind. Hot melt glue used to be used in book binding. However, it lost its strength with time. This was not ideal for books that were to be preserved for a long time. This continued until 1980 when a new discovery was made.
PUR Glue is strong, flexible and is not affected by water. Cheap and unaffected by the environment can be another advantages of it. Most museum and library books are bound using this adhesive. It is three times stronger than ordinary glue. It can therefore preserve valuable books for years. The difficulties associated with hot melted glue are overcome.
This book binding adhesive needs 24 hours for curing. There's now a new formula that allows the glue to cure fast. It is a slow but sure way of binding your books. It should be handled at the correct temperature and under good ventilation. The adhesive contains Methylene Diphenyl Disocynate (MDI) that causes respiratory problems on prolonged exposure. This adhesive contains lower levels of MDI compared to the hot melt glues.
It is so excellent but costly for pur glue to bind. Before use, read the product's manual. Use the product at the correct temperature and avoid skin contact. This glue can be used at high temperatures. Up to 200F is permissible. The adhesive is unaffected by the migration if ink vehicles. It is durable and never loses its strength.
Glue guns are available as the hot type or the cold type. Both use the thermoplastic sticks. The sticks are classified depending on the plastic they contain. The plastics used very in strength. Some of the plastics used include: ethylene, vinyl acetate, polyethylene, polypropylene among others. The sticks are melted before application on the surface.
The guns may be cordless or, they may be powered by the mains. The cordless type may be powered by batteries. The plastic used must therefore have a low melting point. The cold type of guns work on low temperatures. Most work at around 250 degree Celsius. The cold type are used for substances that are damaged by high temperatures. They are also used when little strength is required. They can be used for clothes, craft materials and laces.
High temperature glue guns work at around 380 degree Celsius. They are used when much strength is required. They should not be used with substances that are damaged by hot plastic. These guns can be modified to work at low temperatures. Cordless guns are usually of the cold temperature type. Be careful when using the hot type. They can burn your hands. The hot plastic should not be touched until it has dried and cooled.