AIC 53rd Annual Meeting

The Conserving Canvas Initiative project focused on reformulating BEVA 371 has completed its goal of making a new formulation of Beva 371 with the same activation properties of the formulation developed by Gustav Berger in the early 1970s. This became necessary because after about 2005 the main tackifier was discontinued, coincidentally around the time of Berger’s death, and the formulation containing the substitute tackifier required more heat to properly activate. Berger recommended 65 °C as the activation temperature and noted that it acted as a heat-set adhesive, not a hot melt adhesive. Posthumous formulations after 2005 perform more like  hot-melts and require activation temperatures of 70 °C. Through collaboration with the University of Akron (UA) Polymer Science and Engineering department, test formulations were screened and evaluated through a range of end-user testing methodologies common to Paintings Conservators working in museums and in private practice. Peel strength and shear studies were carried out at UA on mockups of paintings on linen and advanced shear testing was carried out at Virginia Tech. The Akron-optimized formulation is phthalate-free and has proven to have heat-set activation properties akin to Berger’s formulation. In addition to films and solutions currently available commercially, Akron is investigating solvent-free pellets and non-woven sheets of the formulation. The non-woven consists of monofilament that is pure adhesive cast onto release paper, similar to how the film is currently produced; it does not rely upon a carrier. The benefits of a heat-set adhesive based on the semi-crystalline EVA copolymers used in BEVA 371 and the prospects of the formulation available in both pelletized and non-woven forms are discussed.

Conflict of Interest: This research has been fully funded by the Getty Foundation and the authors have no financial or material interest in CPC or CTS, the producers of BEVA products.