Development of A New Process for Manufacturing Micro-Capsule by Using Binderless Granulation and Coating

为开发一种以玉米淀粉为原料，乳糖为薄膜包衣的微胶囊制备工艺，以玉米淀粉和乳糖粉为原料，进行了无粘结剂造粒和包衣试验。然而，由于包衣过程中颗粒的机械强度不足，这项工作不得不被迫停止。因此，性能（尺寸分布，机械强度）和颗粒的产量和操作变量之间的关系进行了检查，通过进行无粘合剂造粒实验，以获得基本的调查结果，作为这个新工艺的发展的初步阶段。主要研究结果如下：1.实验装置和实验条件：采用丙烯酸树脂制成的二维锥形流化床（喷动床型）进行造粒实验。柱厚10mm，锥角15 °。气体入口为10平方毫米。柱宽变化 关于我们 可从150mm到500mm。使用44 μ m开口的不锈钢网作为气体分布器，并使用空气作为流化气体。将具有0.3、0.6和1.0 μ m窄切的氧化铝颗粒用作进料粉末。在不同的操作条件下，如粉末的进料量，气速，操作时间和柱宽进行造粒实验。结果：（1）颗粒呈球形，粒径分布符合对数正态分布，颗粒大小与粒径成正比。(2)利用塔内干舷区的分级现象，可以获得所需最小粒径的颗粒。(3)当保证平稳流化状态时，获得具有几乎相似的物理性质的颗粒，而不管操作变量，如粉末的进料量、气体速度和床宽。(4)对于较大的颗粒（1.0 μ m颗粒），沟道作为造粒的障碍物易于形成。(5)颗粒的表观抗压强度随颗粒粒度的增大而减小，随进料粒度的减小而增大，与操作条件几乎无关。少

To develop a process for manufacturing micro-capsule of cornstarch covered with thin lactose film, experimental work on binder1ess granulation and coating using cornstarch and lactose powder as feeding materials was started. However this work had to be stopped unwillingly because of insufficient mechanical strength of granules in the coating process. Consequently, the relations between the properties (size distribution, mechanical strength) and yield of granules and operational variables were examined by performing binderless granulation experiments for obtaining fundamental findings as a preliminary stage of the development of this new process. The summary of the results is described as follows.1.Experimental apparatus and conditions : A two dimensional tapered-fluidized bed column (spouted bed type) made of acrylic resin as used for granulation experiments. The thickness and taper angle of the column were 10mm and 15 degrees. The gas inlet was 10mm square. The column wideness was var … More iable from 150mm to 500mm. Stainless steel mesh with opening of 44 mu m was used as gas distributor and air was used as fluidizing gas. Alumina particles with narrow cut of 0.3, 0.6 and 1.0 mu m were used as feeding powder. Granulation experiments were conducted at various operational conditions such as charge amount of powder, gas velocity, operation time and column wideness. Granule size was measured by sieving and yield of granules was obtained by weighing the amount of granules discharged from the column after each run.2.Results : (1) The granules were spherical and their size distribution obeyed log-normal distribution. (2) The granules having a required minimum size could be obtained by utilizing classification phenomena in the freeboard region of the column. (3) When the smooth fluidizing state is ensured, the granules with almost similar physical properties were obtained irrespective of operational variables such as charge amount of powder, gas velocity and bed wideness. (4) For relatively large particLes (1.0 mu m particles), the channeling as an obstruction of granulation is liable to set in. (5) Apparent compressive strength of granules which was almost independent of the operational conditions, decreased with the increase of granule size and increased with the decrease of feed particle size. Less