|Budget Amount *help
¥15,200,000 (Direct Cost : ¥15,200,000)
Fiscal Year 2005 : ¥3,800,000 (Direct Cost : ¥3,800,000)
Fiscal Year 2004 : ¥5,000,000 (Direct Cost : ¥5,000,000)
Fiscal Year 2003 : ¥6,400,000 (Direct Cost : ¥6,400,000)
In order to materialize the separation/distinction method for polymer waste materials by utilizing the melt-sticking phenomena, we proposed novel methods for separating the materials continuously from the crashed polymer wastes, i.e. the mixture of various kinds of polymers, and for distinguishing the polymer material that makes the plastic parts of waste industrial products collected from the market, and investigated the feasibilities of these method experimentally. At the same time, basic characteristics of the melt-sticking phenomena, which are the principle of these separation/distinction methods, between the heated solid and polymer materials were examined to clarify the relation between the heating temperature and the sticking/separation forces of the polymer materials. As the results, the following findings valuable for embodying these separation/distinction methods have been obtained.
(1) As the test apparatus for continuous separation of the polymer materials from the crashed p
olymer wastes, a system having plural pairs of a heating roller-heated at different temperatures and a pressing roller covered with a soft material such as rubber was fabricated, and its effectiveness was experimentally examined. The results showed that, in order to enhance the separation ability of this apparatus, the gap between the heating and pressing rollers should he carefully adjusted so as to fit the size of polymer particles passing through it, and that, under the optimized conditions, four kinds of polymer materials is successfully separated by using the system having three successive stages of the separation rollers. It was also shown that the separation ability of this apparatus is markedly enhanced by passing the polymer particles through a certain pair of the heating and pressing rollers several times.
(2) A test apparatus for distinguishing the polymer material of an un-crashed part of waste industrial products was fabricated, and the feasibility of this system was experimentally investigated. In this apparatus, solid particles heated at different temperatures are pressed against the surface of the polymer part, and the material of the part can be distinguished by the sticking behavior of the solid particles. From the experimental results, it was shown that the sticking behavior of the heated particles is affected not only by the initial temperature of the particles and by the material of polymer parts, but also by the pressing duration of the particles against the polymer surface. This is because the particles' temperature gradually drops due to heat transfer between the particles and the polymer parts during pressing. From the results, relation between the particles' initial temperature and pressing duration required for making the sticking take place was formulated, and under the optimized conditions it was proved that four plastic parts made of different polymer materials is successfully distinguished by using this system.
(3) From the basic investigation about the melt-sticking phenomena between heated solids and polymers, it was shown that the sticking force emerges steeply when the interface temperature exceeds the glass-transition temperature or the softening temperature of the polymer materials. However, separation force, i.e. the force required for separating the stuck polymer, decreases with increasing the polymer temperature over the glass-transition/softening temperature, because of the bulk deformation of polymer during the separation, and it consequently has a maximum when the interface temperature is at the glass-transition temperature or the softening temperature of the polymer materials. Less