Hide and bone glue

Table 3 Comparative Properties of Hide and Bone Glues ...

Animal (Colla) Impure gelatinous mattet of animal origin, most commonly bone glue made from hides and bones, casein glue made from skimmed milk, and fish glue made from fish skins [Hackh s... 

Glue.—Hide-glue is usually concentrated from 2 to 15 per cent solids, and bone glue from 3 to 20 per cent in a horizontal-tube or rapid-circulation type double or triple effect evaporator. The capacity is from 2 to 2 gal. per square foot with a steam pressure of 5 lb. and a vacuum of 27 in. Evaporators are built of cast iron with copper or brass tubes. 

Animal glues are derived by the hydrolysis of the protein constituent collagen of animal hides and bones. Collagen in its natural state is water insoluble and must be conditioned to solubilize the protein. Collagen molecules are triple helices of amino acid sequences and contain both nonpolar and charged acidic and basic side chains. The conversion of... 

In the Middle Ages, the first glue-boiling plants came into being and produced protein glues from animal raw materials (glutin from hides and bones, blood albumin, casein from milk) or starch paste from plants. 

Both low test hide glue and bone glue have played an important role in the manufacture of gummed tape. Glue has to a certain extent been replaced by dextrin or combined with dextrin... 

Animal glue - This is obtained from the hydrolysis of the protein collagen which is extracted from animal hides and bones. It is still used as an adhesive in wood working and as a paekaging adhesive for tape, fiber cans, and paper tubes. 

Syn. Animal Glue Technical ->Gelatin G. Tierischer Leim E colie forte G. derives from the protein - collagen, extracted from hides and bones of animals. Animal glue and gelatin have the same structure (- gelatin). G. can be made from bone or skin wastes. Waste fish proteins are sometimes also used. 

Finally, a large variety of hot-melt or thermoplastic adhesives have been developed in recent years. These are solid at normal temperatures, but melt and flow if heated and re solidity when cooled. A wide range of melting points and bond strengths are available, depending on the requirements of the application. These adhesives are widely used in furniture and cabinet construction and have largely replaced the hide/bone glues formedy used in these applications. 

Animal glues are usually made from bones and hide. Casein from milk and fish glues are also of animal origin. 

Gelatin and animal glues (glutines) are extracted from waste bones and hides [30.10, 30.11], Type A gelatin is produced by an acid extraction, while Type B uses an alkali — usually slaked lime. Demineralised bone (ossein) and cattle hide pieces are soaked in lime water at ambient temperature for up to 20 weeks. Additional milk of lime is added to the liquor to maintain the alkalinity. 

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