The functions and operation of batch type rubber mixer are described. The effects of each parameter on mixing are also explained. The case study of the use of computer simulation through the development of Rotors, which have the big effect on mixing, is also presented. Examples of the development of improved mixing machines in response to recent changes in formulation are described.

Rubber mixing process consists of batch weighing, mixing and kneading, sheeting and cooling processes. As several types of mixing machines have been introduced for the core mixing and kneading process in the rubber industry, the selection of mixer type has a significant effect on factory construction and mixing line engineering entirely.

This paper explains in detail the features of a tilting chamber type kneader, which is a kind of internal mixers used in rubber mixing process, in comparison with an opening bottom type mixer, and makes clear its influence to the engineering of rubber mixing lines based on the mixer structural features.

Rubber processing technology including compound design, extruding, and metal mold cure are closely related each other. Especially mixing technology are most important for extruding metal mold cure to produce the high quality products. Because the processing index such as pressure losses of rubber compound are important for establish the most desireble producing condition to produce high quality products. In this report, the relation between mixing index and processing technology of rubber compounds will be discusse.

Cellulose Nano Fibers (CNFs) is expected to be utilized in various fields because of its attractive properties such as high strength, high rigidity, and low coefficient of linear expansion. CNFs have attracted significant attention as materials that can enhance the mechanical properties of polymers. CNFs can easily form hydrogen bonds between CNFs because of the many hydroxyl groups on the surface of a CNF. Therefore, in many cases, CNF agglomerates with diameters greater than 100 µm remain in a composite when compounded with hydrophobic polymers. Recently, we can success in preparing the dry powders of CNFs by coating of hydrophobizing agent and special drying (trial products by Sugino Machine ; 20 nm of fiber diameter, 1 and 10 µm of fiber length) . The CNFs are easily dispersed in a polypropylene (PP) matrix by melt-compounding with using a twin-screw extruder. No agglomerates of CNFs with diameters greater than 1 µm can be found in the composite by optical microscope observations and TEM observations of electron staining ultrathin section.

In this article, we introduce a dispersion mechanism of CNFs in polymers, development of CNF dray powders which are easily dispersed in polymers and the outline of our CNF nanocomposite studies in the joint researches with companies by support programs of MEXT, NEDO and SME Agency.

Melt compounding using an extruder is the method for mixing functionalized materials into plastics to add functionality to existing plastics and improve their performance. The performance of the composites depends on the dispersion state of the mixed materials in the composites. Therefore, the analysis and evaluation of the dispersion state of adding materials in the composites are necessary for considering the performance of the composites. In this article, we focus on the melt compounding of composite materials using thermoplastics and outline the analysis and evaluation methods of melt compounding and mixing process of plastics by an extruder, citing the references. First, we explain the concepts of dispersive mixing and distributive one as the basic theory of melt compounding. Next, we introduce the following examples for the analysis and evaluation of melt compounding by an extruder, 1) Dispersion of binary mixtures, 2) Dispersion of functionalized fillers such as nanoclay and vapor-grown carbon fiber, 3) Evaluation by flow simulation of polymer melts in an extruder, 4) Estimation of pigment dispersion and online estimation during melt compounding as the other topics. Finally, we describe future problems and tasks as the conclusion.