Melt extrusion industry

Hot-melt extrusion is one of the most widely applied processing techniques in the plastics industry. Joseph Brama invented the extrusion process for the manufacturing of lead pipes at the end of the eighteenth century. However, hot-melt extrusion was not applied in the plastics industry until the mid-nineteenth century, when it was first introduced into a wire insulation polymer coating process. Today, hot-melt extrusion is not only widely applied in the production of polymeric articles but also in polymer production and compounding. Currently, more than half of all plastic products, including plastic bags, sheets, and pipes, are manufactured by this process. ... 

For over two decades, the value of continuous processing in the pharmaceutical industry has been recognized. The potential of automation, reduction of capital investment, and the reduction in labor costs has made hot-melt extrusion worthy of consideration. ... 

Clear, transparent films (or fibers) may be obtained by melt extrusion or solvent casting. Although rather similar in their properties to certain polyesters, they failed to achieve industrial applications. 

Different polymers have different unique properties. To combine these unique properties of component polymers blending is an attractive means. There are a few methods to make polymer/polymer blends solution blending, melt extrusion, in situ polymerization, among others. Compatibility usually plays a major role in the development of properties. The blends prepared by melt mixing of thermoplastic materials and rubbers have met industrial needs in recent years. 

By virtue of its well-established nature in a number of industries, scalability, and excellent process control, melt extrusion meets the needs of both biotechnology and small molecule discovery pipelines. Combining this with an ever-expanding compositional knowledge for the technology, melt extrusion will make a clear difference in the future of drug delivery. 

Schenck, L. Troup, G.M. Lowinger, M. Li, L. McKelvey, C. Achieving a hot melt extrusion design space for the production of solid solutions. In Chemical Engineering in the Pharmaceutical Industry R D to Manufacturing am Ende, D.J., Ed. John Wiley Sons, Inc. New York, 2011. 

Uses Fluoropolymer for wire and cable jacketing, melt extrusion and transfer molding, in the chemical industry for chemical linings, bellows, and valve components... 

Uses Melt processable high performance thermoplastic for melt extrusion, coating of fine wire and inj. molding of slender, thin-walled, or intricate shapes, compression and transfer molding for pipes, sheets, and cable jackets in elec, wire insulation, industrial fibers, weather-resist, films, mechanical applies., and in chemical service Manuf./Distrib. Aldrich http //www.sigma-aldrich.com... 

In order to adjust the properties of these starch-based materials to the desired application, it is necessary to combine starch with other polymers, as frequently done in the plastic industry. The need for tuneable properties may also require starch modifications, such as esterification or etherification, grafting and reactive or melting extrusion of thermoplastic starch (TPS). The main forms of starch utilization as a polymer are (i) starch grafted with vinyl monomers, (ii) starch as a filler of other polymers and (iii) plasticized starch (PLS), commonly known as TPS. 

The effect of flow is of industrial relevance in the processing of polymer blends where high deformation rates are encountered, as in melt extrusion or injection molding. 

Several modifications have been proposed to improve the performance of the elastic melt extruder. Fritz [43] suggested incorporation of spiral grooves to improve the pressure generating capability, essentially combining the elastic melt extruder and the spiral disk extruder into one machine. In Russia [47], several modifications were made to the design of the elastic melt extruder. One of those combined a screw extruder with the elastic melt extruder to eliminate the feeding and plasticating problem. Despite all of these activities, the elastic melt extruder has not been able to acquire a position of importance in the extrusion industry. 

Analyses that require numerical techniques to arrive at solutions tend to be quite time consuming and require skilled personnel to develop the computer programs and to interpret the results of the computer simulations. Many people in the extrusion industry do not have the time or inclination to work through elaborate and complex analyses of melting. In this case, the preferred action is to use a less complicated analysis that yields analytical results. In most cases, actual predictions of melting performance can be made with a relatively simple programmable calculator. 

Increasing the barrel diameter will increase the shear rate—other factors being constant. This will increase viscous dissipation and melt temperatures as discussed earlier. Another problem with larger barrel diameters is that the heat transfer surface area increases with the diameter squared, while the channel volume increases with the diameter cubed. As a result, the heat transfer becomes less effective with larger diameter extruders. It is well known in the extrusion industry that the ability to influence melt temperature by changes in barrel temperature is very limited for large extruders. 

Coextrusion Dies. Another type of die used in the extrusion industry is the coextrusion die. This type of die is used to make a multilayered product in one step. There are two main coextrusion systems the feed block system and the multimanifold system. In the feed block system, the different plastic melt streams are combined in a feed block and then fed into a regular single manifold extrusion die (see Fig. 18). 

Schenck L, Troup GM, Lowinger M, Li L, McKelvey C (2011) Achieving a hot melt extrusion design space for the production of sohd solutions. Chemical engineering in the pharmaceutical industry R D to manufacturing. WUey, Hoboken, pp 819-836... 

One of the numerous applications of polymers as formulation excipients in the pharmaceutical industry is their use as matrix formers in the hot-melt extrusion process. Although HME was invented at the end of the 18th century as a method of manufacturing metal parts, its potential for the production and treatment of polymers was recognized and has now become the main production method of plastic materials [1]. However, HME was only recently introduced in the pharmaceutical industry [2], but since its introduction it has opened a new area of industrial application for polymers in pharmaceutical formulation. 

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