An adhesive or glue is a material, usually in a liquid or semi liquid state, that adheres or bonds items together. Adhesives come from either natural or synthetic sources. The types of materials that can be bonded are vast but they are especially useful for bonding thin materials. Adhesives cure (harden) by either evaporating a solvent or by chemical reactions that occur between two or more constituents. Animal glues are essentially high polymer proteins; these glues find application in a wide range of industrial uses. Fish glue as the name indicates, is obtained as the byproduct of the fish skin industry, was the first liquid glue that reached commercial importance and was forerunner of all household glues. Resins are used in the manufacture of adhesives, paints and number of other products. Polyesters are thermosetting and thermoplastic resins for various applications. Due to high cost they are used with other resins for the application of adhesives. Polyamide resins used in adhesives can be divided into four used classes; thermoset adhesives, nylon epoxy adhesives, thermoset plastic adhesives and thermoplastic thermoset adhesives. The adhesives industry has found its place in many industries and will surely spread too many other fields. It is used in building, electrical, automobile, aircraft and aerospace industries. The future advancement and consumption are practically beyond mental comprehension. Even today, as ones surroundings are observed, the use of adhesives, glues and resins are associated with almost every product that is marketed. While use of all adhesives has increased, the greatest gain has occurred in the synthetic resin category. The synthetic resin adhesive is the most important for packaging uses. Pressure sensitive adhesive is a fast growing segment of the industry. This field includes products designed for the industrial trade but which can, by minor modification, be marketed through the hardware dealer and variety store. Adhesives for this growing market range from the simplest glues and mucilage for furniture making and repair, to metal to metal bonding for frame construction.
For more details download PDF file.