Eldridge M. Mount

Aroma, Oxygen and Moisture Barrier Behavior of Coated and Vacuum Coated OPP Films for Packaging

Various coated and vacuum coated, biaxially oriented polypropylene film product designs are examined in terms of their moisture, oxygen and aroma barriers. Factors that are thought to control oxygen barrier in these products are discussed and extended to aroma barrier development. The differences between the various vacuum coated and uncoated films with three organic permeants are evaluated and discussed in relationship to the impact on the polymer/coating interface and the development of aroma barrier in coated films. It is demonstrated that the existence of an evaporated barrier layer does not guarantee the existence of a chemical barrier. New combinations of film technology are described that permit the development of excellent aroma, oxygen and moisture barrier films.

9 – Twin Screw Extrusion Process

This chapter discusses extrusion of polymeric materials to produce finished products for industrial or consumer applications, which is an integrated process, with the extruder comprising one component of the entire line. In some applications, the production lines are very long with numerous operators, requiring operators to communicate and work together to produce an acceptable finished product.

Design of Experiments

Design of experiments, referred to as DOE, is a systematic approach to understanding how process and product parameters affect response variables such as processability, physical properties, or product performance.

Plastic Behavior in the Extruder

Polymer response or behavior in the extruder, combined with the extruder processing conditions, i.e. barrel temperatures, screw speed, and screw design, allows the extruder to extrude a homogeneous polymer melt at a constant pressure and temperature.

Polymer Overview and Definitions

To troubleshoot and solve extrusion process problems, it is important to understand both the equipment operation and the polymer being processed. Understanding either the equipment or the polymers alone may not provide enough information to solve a particular extrusion problem. This chapter covers the definition of polymers, how they are formed, different types of polymers, and their structures.

11 – Twin Screw Extruder Equipment

There are many twin screw extruders commercially available, and the choice should depend on the end-use application.

Pipe and Tubing Extrusion

Pipe and tubing is profile extrusion with dies designed to produce round cross-sections. A pipe and tubing extrusion line is like a profile line except it uses a vacuum sizing cooling unit rather than a cooling or calibration tank.

22 – Processing Recommendations for Various Resin Systems

Extrusion processing condition guidelines for different resin systems are summarized in this chapter. These conditions are good starting points for the various resin systems and may require optimization for a specific extrusion process to obtain the maximum throughput rate while meeting or exceeding all the quality criteria.

Single Screw Extruder: Equipment

What are the objectives or goals to be accomplished with the extruder in the overall extrusion process? The standard answer is to produce a quality product that meets the customer specifications 100% of the time. Although this is true, the extruder has five distinct goals or objectives to achieve in the extrusion process that will result in a quality product if done correctly.

Polymer Selection for Coextrusion

To produce an acceptable coextruded structure, proper resin systems have to be used with the correct die and/or feedblock technology. Just having the proper extruder, feedblock, and die design will not guarantee successful coextrusion.