Effects of the compatibility of a polyacrylic block copolymer/tackifier blend on the phase structure and tack of a pressure‐sensitive adhesive

Abstract

Adhesion and viscoelastic properties and morphology of a polyacrylic block copolymer/tackifier blend were investigated. Special rosin ester resins with different weight average molecular weights of 650, 710, 890, and 2160 were used as the tackifier and blended with a polyacrylic block copolymer consisting of poly(methyl methacrylate) and poly(n-butyl acrylate) blocks at tackifier content levels of 10, 30, and 50 wt %. The compatibility decreased with an increase in molecular weight. From TEM observation, the number of formed agglomerates of the tackifier with sizes on the order of several tens of nanometers increased with increasing tackifier content and molecular weight of the tackifier in the range from 650 to 890. For the tackifier with a molecular weight of 2160, micrometer-sized agglomerates were observed. The storage modulus at low temperature and the glass transition temperature of adhesive measured by a dynamic mechanical analysis increased dependent on the number of formed nanometer sized agglomerates. Tack was measured using a rolling cylinder tack tester over wide temperature and rolling rate ranges, and master curves were prepared in accordance with the time-temperature superposition law. Tack and peel strength were optimum at a blend combination of intermediate compatibility, i.e., the molecular weight of 890. These optimum properties were correlated to maximal values of the storage modulus at room temperature and the glass transition temperature. Therefore, it was found that these features of blend properties are strongly affected by the nanometer sized agglomerates of tackifier.

Study on the synthesis and application of silicone resin containing phenyl group

“…As materials with broad application, they have outstanding heat resistance, water resistance, ultraviolet resistance and improved adhesion [2][3][4]. SPSA have traditionally been made by compounding a silicone resin and a high molecular weight polydimethylsiloxane [5]. Silicone resin is chemical compounds used in formulating adhesives to increase peel strength and the stickiness of the surface of the adhesive.…”

Influences of debonding rate and temperature on tack properties and peel behavior of polyacrylic block copolymer/tackifier system

“…However, it must be taken into consideration that the average molecular weight of MAM-16 is far greater than that of MAM-23. The phase structures of base polymer and tackifier-added system were reported previously [19] as mentioned in the introduction part.…”

“…previous report [19], both the temperature and frequency dependencies of the storage modulus were measured for MAM using dynamic mechanical analysis. The storage modulus decreased with an increase of temperature or by lowering the frequency, where the frequency is equivalent to the debonding rate.…”

“…We have already investigated the adhesion mechanism of tackifier-added block copolymer system. [19] A sea-island structure with spherical PMMA domains possessing a mean size of about 20 nm dispersed in the PBA continuous phase was observed in all base polymers using transmission electron microscopy (TEM). A special rosin ester was used as a tackifier.…”

“…The tackifier hardens PBA (increases both E′ and T g ) at lower temperature, but softens it at higher temperature. As previously reported [19], the frequency dependence of the MAM/tackifier system was measured and the tendency was similar to the temperature dependence according to the time-temperature superposition law. [21][22][23][24][25] For viscoelastic polymers such as PSAs, the polymer property at high and low temperatures is the same as those …”