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Property Improvements of SBC Adhesive with Low Molecular Weight PPO Resin -- Effect of Loading and Processing Conditions Disclosure Number: IPCOM000005669D
Publication Date: 2001-Oct-24

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The Prior Art Database


PPO SA120 resin is a new low molecular weight (Mn »2500) polyphenylene-ether (PPE) resin recently commercialized by GE Plastics as a polymer additive. In addition to having the well-known properties inherent to PPE, this new resin has an excellent thermal performance--glass transition temperature (Tg) of 165°C combined with a characteristic feature of improved processability. PPE and polystyrene (PS) are inherently miscible evidenced with a linear Tg increase as a function of PPE loading. The same principle applies to the polystyrene phase of Styrenic Block Copolymers (SBC). Due to the molecular weight constraint of the polystyrene end-blocks in most SBCs used for adhesives, conventional high molecular weight PPO resin fails to express its beneficial properties. However, for the new PPO SA120 resin, its optimal end-block compatibility makes it an ideal candidate for improving the property profile of SBC-based adhesives and sealants. Reported herein is an evaluation of PPO SA120 resin in tape and assembly adhesives for solvent and hot-melt applications. A special procedure has been developed that allows PPO SA120 resin to be processed into unsaturated mid-block rubber SBC hot melts at 150-170 °C. Relatively small amounts of PPO SA120 (preferably less than 5%wt) have resulted in a significant increase of the Shear Adhesion Failure Temperature (SAFT up to 20°C). This has been achieved without sacrificing other adhesive properties, such as Tack and Peel Strength. Enhancement in these adhesive properties has been observed in certain cases. In all formulations tested similar property improvements for unsaturated SBC based adhesives have been observed at low PPO SA120 resin loading. Key Words: polyphenylene oxide, PPO, polyphenylene ether, PPE, SBC, styrenic block copolymer, adhesive, hotmelt, SEBS, polystyrene, sealant, tape, assembly, SAFT, shear adhesion failure temperature, end-block reinforcer, Z-blade, coatings