1 INTRODUCTION

ACRYLIC AND OTHER POLYMER DISPERSIONS have been used as adhesives and in paint media for more than 20 years. These synthetic polymers have found sporadic use in the conservation field as well, specifically for consolidating fragile materials and lining paintings. Properties such as permanence, stability, and reversibility, important to the conservator, are not always important in industry; yet often these materials have been adapted for use in conservation without extensive testing.

This study focused on the practical reliability of five polymer dispersions used frequently in paintings conservation: Plextol B500, Rhoplex AC 33 and AC 234, and Lascaux 360 HV and 498 HV. These adhesives were chosen because they are readily available to the conservator. Properties of peel strength (reversibility), color change, and swelling of dried films (solubility) were examined. Both aged and unaged samples were tested and examined for flexibility. Consideration of these data provided information about the long-term stability of these products.

In a recent paintings conservation refresher course sponsored by the FAIC, these materials were demonstrated to have advantages in their low toxicity, ease of short-term reversibility, and compatibility with other materials. Disadvantages included the risk of moisture reactivity when used as a wet laminate, some application difficulties with large fabrics, changing of product formulation without notice, and, most important, the lack of comparative testing.1