Nishiyama and C. Sato Abstract

Adhesion - Current Research and Application. WulfF Possart Copyright 2005 WILEY-VCH Verlag GmbH Co. KGaA, Weinheim ISBN 3-527-31263-3 

Recycling of industrially produced material is important from the environmental point of view. For the recycling of materials bonded with adhesives, dismantlement of the products is necessary to separate them, although that is quite difficult. Therefore, a novel technique by which adherends can be dismantled easily has to be established. A conventional way to solve the problem is the use of thermoplastic adhesives because they soften at high temperature and joints bonded with them can be separated by applying small forces. Recently, a new kind of adhesive including thermally expansive microcapsuies has been proposed as an alternative method [1]. A joint bonded with such an adhesive can be dismantled by heating, as shown in Fig. 34.1. 

Adhesive including thermally expansive mic recap sule 

The expansion behavior of the microcapsules was measured by a PVT (pressure-volume-temperature) apparatus [12, 13] since it is also very important for the design or for modification of the microcapsules. The expansion behavior of the adhesive is discussed on the basis of the experimental results. 

As the filler of the dismantlable adhesive, thermally expansive microcapsules (Matsumoto Microsphere F-30 Matsumoto Yushi-Seiyaku Co. Ltd.) were used. They consisted of a poly(vinyl chloride) shell filled with liquid hydrocarbon (H-quefied isobutane) as shown in Fig. 34.2. The diameter of the microcapsule was 10-30 pm and the average was 20 pm. The shell thickness was 3—4 pm at room 

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