Casein adhesive

Description

A clear, viscous solution formed when Casein, a milk protein, is soaked in water with an alkali (Ammonium carbonate, Borax, Lime, etc.). The alkali hydrolyzes the casein to make a solution that is usually stable for several weeks. Occasionally a plasticizer, such as Glycerol or Sorbitol and a preservative, such as Phenol, are added to the solution. Casein glues were used since ancient times as a water-proof adhesive. In the Renaissance period, casein was used for picture frames. Lime casein glues were first patented in the mid 19th century. They were an important commercial glue through W.W.I for applications such as furniture, plywood, and airplanes because they were more moisture resistant than animal glues. Casein glues were mostly replaced by phenolic, Resorcinol, and urea formaldehyde adhesives in the 1930s and 40s.

Synonyms and Related Terms

colle caséine (Fr.); cola de caseina (Esp.); colla di caseina (It); casein glue; ammonium casein; borax casein; lime-casein; lime casein

Risks

• May yellow with time.
• Susceptible to microbiological attack.

Physical and Chemical Properties

• Borax casein = pH (7.0-7.8); lime-casein = pH (9.0-9.9); ammonium casein = pH (8.0-9.0).
• Insoluble in water or ethanol when dry. Soluble in strong alkalis and ammonium hydroxide.

Resources and Citations

• H.K.Salzberg, "Casein Glues and Adhesives" in Handbook of Adhesives, I.Skeist (ed.), Van Nostrand Reinhold, New York, 1977, p.158-171.

• Dictionary of Building Preservation, Ward Bucher, ed., John Wiley & Sons, Inc., New York City, 1996

• Encyclopedia Britannica, http://www.britannica.com Comment: "adhesive" [Accessed February 12, 2002].

• The Dictionary of Art, Grove's Dictionaries Inc., New York, 1996 Comment: "Adhesives"

• Theodore J. Reinhart, 'Glossary of Terms', Engineered Plastics, ASM International, 1988

• Art and Architecture Thesaurus Online, https://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000