The Ministry of Food Processing Industries (MOFPI) is supporting the “Make in India” initiative with the focus on the reduction in the wastage of perishable agricultural produce and enhancing shelf life of processed food products thereby ensuring value addition to agricultural produce.

Multilayer rigid plastic container for Food Packaging will be very useful as one of the tools by the food processing industry in achieving the goals of “Make in India” with modern improved way of packaging and also reduction in the wastage of perishable agriculture produce along with enhanced shelf life. 

Conventional rigid plastic containers such as PET, HDPE, PP and LDPE containers are commonly used in the food industries; but these containers do not offer sufficient barrier required against the Oxygen gas which is very detrimental for the products shelf life.

Glass containers on the other hand have its own problems such as heavy weight of the container, high transport cost for empty as well as filled containers, difficult handling, design freedom and injury during handling. This makes glass containers less preferable as compared with the plastic containers.

In order to increase the product’s shelf life, a barrier layer of EVOH is introduced into the plastic container to decrease the permeability of gases, aromas and moisture. These containers are also known as multilayer EVOH containers or Co-extruded containers or simply Co-ex containers.

Multilayer EVOH plastics containers; because of their high barrier properties gives extended shelf life and in turn can be used for replacement of glass and aluminium packaging.

Structure of Multilayer Containers:

The six layer structure of co-extruded container is as given below. The regrind layer is either next to outermost Virgin HDPE / PP layer or the innermost HDPE/ PP layer.

Inner Virgin HDPE / PP                                     (1)
Process grind Layer                                          (2)
Adhesive Layer                                                 (3)
Barrier Layer (EVOH)                                        (4)
Adhesive Layer                                                  (5)
Outer Virgin HDPE / PP                                     (6)

The raw material used for the majority thickness of container shall be HDPE or other materials such as Polypropylene (PP) as agreed between buyer and seller.

The adhesive layer used is EAA based polymer. The barrier layer used is usually EVOH.

Advantages of using Multilayer / Co-extruded containers having EVOH as barrier layer: -

diagram
                    
Superior Gas and Moisture Barrier Properties
- EVOH based Multilayer containers provide excellent barrier properties against the permeation of gases. It exhibits superior barrier compared to any other conventional polymers. The gas barrier prevents oxygen from penetration thus preventing the spoilage of the contents and preserves the organoleptic properties of the product.. 

Barrier to Aroma or Flavour Permeation
- The EVOH layer provides an excellent barrier against the permeation of aroma. Thus EVOH based Multilayer packaging containers provides high aroma retention for use in food packaging. This helps in retaining the value of the product till it reaches to the ultimate customer.

Resistance to Oil
- EVOH provides effective barrier to oils and organic compounds by way of reduced oxygen permeation through the packaging wall.

Weather Resistance
- EVOH based multilayer plastic container provides good weather resistance to outdoor exposure. Since the EVOH is sandwiched between other polymer layers hence its barrier remains intact during transportation, handling and storage. 

Hot Filling of Container
- The biggest advantage with these EVOH based Multilayer container is that the products can be hot filled at 75 to 80 deg C; this helps in enhanced production on the shop floor for the products.

Co-extruded plastics containers because of their non-porous property gives extended shelf life and in turn can be used for replacement of glass, Tin and aluminium packaging in most of the food products.

Advantages of using Multilayer Containers over Glass and Metal packaging:

The comparative advantage of the Multilayer Barrier Containers as compared with the Glass and Metal containers is described in the below table.

Table

Case Study:

The below case study is based on the Ketch up Container.

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About the author

Bhupendra Singh

Bhupendra Singh is a Polymer Technologist from UDCT Mumbai with rich experience in Technical Consultancy and Polymer, Packaging Businesses for the last 18 years.
He is the associated with Tekno Solutions & Grace Technologies based out of Navi- Mumbai. He is currently active in the field of Chemical additives, Packaging and Printing segment. He has rich experiences in the Projects, Product developments, Regulatory & Marketing field.

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