Embodiment of the Separation/Distinction Method for Polymer Waste Materials by Utilizing Melt-Sticking Phenomena

为了实现利用熔粘现象对高分子废弃物进行分离/区分的方法，我们提出了从破碎的高分子废弃物（即各种高分子的混合物）中连续分离材料的新方法，以及从市场上收集的废旧工业产品中区分制造塑料部件的高分子材料的新方法，并对这些方法的可行性进行了实验研究。同时，研究了被加热固体与高分子材料之间熔粘现象的基本特征，即这些分离/区分方法的原理，以阐明加热温度与高分子材料的粘粘/分离力之间的关系。作为结果，得到了以下有价值的发现，体现了这些分离/区分方法。(1)采用多对加热辊（不同温度加热）和压辊（覆盖橡胶等软质材料）组成的系统，作为从破碎废渣中连续分离高分子材料的试验装置，并对其有效性进行了实验检验。结果表明，为了提高该装置的分离能力，应仔细调整加热辊与压辊之间的间隙，以适应通过该装置的聚合物颗粒的大小，在优化的条件下，采用连续三级分离辊的系统，可以成功地分离出四种聚合物材料。实验还表明，将聚合物颗粒多次通过一对加热压辊，可显著提高该装置的分离能力。(2)研制了工业废旧产品未破碎部分高分子材料识别试验装置，并对该系统的可行性进行了实验研究。在该装置中，在不同温度下加热的固体颗粒压在聚合物部件的表面，并且可以通过固体颗粒的粘附行为来区分部件的材料。实验结果表明，受热颗粒的粘附行为不仅受颗粒的初始温度和聚合物部件材料的影响，还受颗粒对聚合物表面的挤压时间的影响。这是因为在压制过程中，由于颗粒和聚合物部件之间的热传递，颗粒的温度逐渐下降。根据实验结果，建立了颗粒初始温度与粘接时间之间的关系式，并证明了在优化条件下，该体系可成功区分出4种不同高分子材料的塑料部件。(3)对加热固体与聚合物的熔粘现象进行了基础研究，结果表明，当界面温度超过玻璃化转变温度或聚合物软化温度时，黏附力急剧增加。而分离力，即分离黏附聚合物所需的力，随着聚合物温度在玻璃化转变/软化温度上的升高而减小，这是由于聚合物在分离过程中会发生大块变形，因此在界面温度为玻璃化转变温度或聚合物材料软化温度时分离力最大。少

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 … More 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