New Acrylic Block Elastomer for Adhesive Applications
Developed using proprietary living anionic polymerization technology, a new acrylic thermoplastic elastomer is suitable as an adhesive for masking tape, packaging, surface protection film, double-sided tape, and as an anti-slip film.
The authors have developed the world's first acrylic thermoplastic elastomer (TPE) with the best weather resistance currently on the market, using proprietary living anionic polymerization technology. The acrylic TPE is a block copolymer consisting of two polymethyl methacrylate (PMMA) blocks (glass transition temperature: 100-120 °C) and a variety of acrylic ester blocks (glass transition temperature: -70 to -50 °C) in between them (Figure 1).
The size exclusion chromatography curve of the final block copolymer obtained by this technique shows a unimodal peak with no trace of the intermediate homopolymer (which is PMMA) or diblock polymer, and its molecular weight distribution is narrow, less than 1.3. The polymerization conversion of monomers at each stage is virtually 100%, and there are very few low molecular weight impurities such as residual monomers. Since the acrylic TPE is a block copolymer, the microphase-separated structure that can be obtained depends on the molecular weight and percent composition of each block, and the physical properties change with differences in these parameters. When the PMMA ratio is high, it takes on a lamellar structure and becomes a hard material that does not crack easily when bent, and is used as a molding material for smartphone cases and as a modifier for various resins (such as polycarbonate, ABS, and PVC).