Impact of volatile organic compounds (VOCs) from acrylic double-sided pressure-sensitive adhesives (PSAs) on metals found in cultural heritage environments

Abstract

An artificial aging protocol known as the Oddy test was combined with headspace solid phase micro-extraction (SPME) gas chromatography-mass spectrometry (GC–MS) data to identify which of 17 double-sided acrylic pressure-sensitive adhesives (PSAs) were safest to use in cultural heritage environments. Traditional Oddy testing showed every PSA corroded lead coupons while 1 also corroded copper and silver coupons. 10 PSAs were suitable for short-term use near cultural heritage artifacts while the remaining 7 were unsuitable. An adapted Oddy test identified whether several known acrylic-based adhesive precursor chemicals, including ethyl acrylate, n‑butyl acrylate, 2-ethylhexyl acrylate, acrylic acid, and abietic acid caused the observed corrosion. Lead coupons were extremely sensitive to acrylic acid, with a 5 × 10−5 mg L-1 Oddy test jar concentration capable of initiating corrosion at 60 °C and 50% RH. SPME GC–MS showed that any evidence of acrylic acid or acetic acid with peak areas larger than 19 million were both markers for unsuitable PSAs. 2-ethylhexyl acrylate was less reactive to metals though a GCMS peak area greater than 200 million was correlated with unsuitable PSAs. 3M™ 465, 3M™ 908, and Tesa® 88,250 tapes were concluded to be the best double-sided PSAs for use in cultural heritage environments.