(1) Animal Glue
In umu le mini known types of glue Kak. This material is made of collagen (a protein animal skins, bones and bone connective meat). The specialty of this material is soluble in hot water, and the cooling time clotting occurs such as agar-agar (jelly), so that it can generate power lam first adhesive that is strong enough. In the subsequent drying there was a strong adhesive power. Kak glue is there in the market in the form of granulate (grain), potonganpotongan and slabs.
(2) Casein
Casein is a protein substance found in animal milk (cow) as a byproduct of the cheese company. Casein solution in the form of pastes used on label paper sticking to glass bottles.
The specialty of this casein glue is the result penempelannya is resistant to moisture and also tehan to water, so if the bottle is submerged in water the paper will not come loose.
(3) Starch and Dextrin
Starch or starch are the result of the plant, an example of which we have encountered is made from tapioca starch. This material has been known since long ago as glues, is a way to cook it with water. Dextrin is chemically modifokasi result of kanji. Both of these materials are widely used in the manufacture of paper bags, cardboard boxes, and others.
(4) Poly Vinyl Acetate
Poly vinyl acetate or abbreviated to PVAC is a resin (polymer) of the results of polymerization in which a material is vinyl acetate monomer. The results of this polymerization shaped disperse or emulsified in water, white and pasta. Poly vinyl acetate is used widely in the field of glue since 1940 in lieu of glue Kak (animal glue) in the timber industry. PVAC is very suitable to be used on the machines of high speed wrapper.
Also, PVAC used on the machines bookbinders, paper bags, cover the making, and others. Chemically poly vinyl acetate having clusters of atoms are active so that it can bind other materials by means of hydrogen bonding and chemical adsorption.
(5) Urea Formaldehyde
The progress achieved in terms of adhesion to the timber was the invention of a synthetic adhesive material in mid 1930. This syntactical adhesive is Phenol Formaldehyde and Urea Formaldehyde. Caused cheaper, then Urea Formaldehyde is more widely used than others. Urea Formaldehyde is widely used in the manufacture of plywood. In its use is sometimes mixed with wheat flour for making flexible gluing results.
The resin is mixed with hardener in the water and then add the flour as a filler and then the catalyst substance. This slurry is spread onto the surface layer of wood with a roller spreader. Layers of thin wood (veneer) which has dispread with urea glue is then composed of three layers (plywood) and pressed with heated with steam for 4 to 7 minutes, with the temperature or the temperature of steam between 125 degrees to 140 degrees Celsius.