Resins are found in nature and are chiefly of vegetable origin.
Resins are soluble in alcohol, ether, and many hydrocarbons but are insoluble in water.
When heated, they soften and finally melt. Their chemical composition varies, but most are mixtures of organic acids and esters. Resins are generally classified according to their source or by such qualities as hardness or solubility. Other resins are exceedingly hard and resistant to most solvents, softening only at high temperatures. Click here to see documents from Electric Library, a pay service.