Animal origin, 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... 

Products of animal origin animal glues, casein... 

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

Plant Resin Formulations, Sometimes compounded with shellac, as in DeKhotinsky cement, these compounds have long been used as hot-melt glues. Likewise, waxes of plant and animal origin have also been used as hot-melt adhesives (22). They all should be reversible by application of heat, possibly in conjunction with solvent action in the more diflScult cases. 

Glues of animal origin are very prone to biodegradation and will fail rapidly in hot damp conditions. 

Solutions of natural and synthetic high molecular mass substances in water, e.g., starch, dextrins, casein, cellulose ethers, water-soluble derivatives of poly(acrylic acid), poly(vinyl alcohol), poly(vinyl pyrrolidone) (adhesive sticks). Uses paper, fiberboard. Glutins (glues of animal origin). Uses wood, paper, fiberboard, moistenable adhesive tapes. 

Any conservation material or technique used should produce results that are reversible and not permanently bonded to the artist s original work this allows for the removal of conservation treatments that later no longer serve their intended purpose. This constraint alone eliminates all thermosetting type adhesives because of their thermal irreversibility. It also excludes adhesives that are applied as solutions of low molecular weight material, due to their tendency to penetrate and dry in unreachable areas. Lining adhesives have therefore been limited in principle to stable, thermoplastic materials. One important exception is the use of starch and animal type glues discussed in section 4.1. These adhesives arc not readily reversible by thermal means and arc usually removed... 

From antiquity, glues had been made almost entirely from materials of animal or vegetable origin, and were sensitive to moisture, oxidation, and bacterial or fungus attack. Because of these deficiencies, production of durable plywood, for example, was not possible. The modern plywood industry actually owes its growth to the availabiUty of relatively low cost urea adhesives. Plywood and chipboard or wood chip glues are often made at the plywood and chip board mill. 

Tannin-containing woods also darken with ammonia, a process which is usefully employed in darkening oak furniture by fuming . Ammonia stains can originate from animal glue, amino-type adhesives and concrete additive sources, particularly where damp conditions exist. 

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