https://www.ppg.com/en-US/aerospace/product/pr-188-universal-sealant-adhesion-promoter/PLP0000015825
PR-188 Adhesisive Compound Promoter for Aerospace | PPG
PPG PR-188 Adhesive Compound Promoter enhances adhesion of polysulfide and polythioether sealants to aerospace substrates, fully qualified to AMS 3100.
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