Monday, September 1, 2008


It is a matter of great concern that plastics have become omnipotent in almost all spheres of life and many countries are facing severe environmental problems due to accumulation of these biologically indestructible materials. While burning off presents the problem of dioxin pollution of the atmosphere, dumping often causes choking of drains in many urban areas besides adversely affecting the soil quality. Recycling is fraught with its own problems too, though the recent reported use of plastics for road building is a welcome development. Many states in India have put in place a ban that is supposed to prevent use of thin plastic carry bags for shopping purposes.

As an alternative to plastics, paper has been touted and many supermarkets in many developed countries provide bags made from recycled paper to their customers in place of plastic bags. Even re-use of plastic bags was promoted with incentives so that their use can be multiplied several times before disposal. Years ago in India itself use of cloth bags was advocated especially for distribution of grains through the PDS though very little was done to pursue the proposal. Compared to many other countries, in India there is an active market for old news papers which are collected from house holds by small dealers for supply to recycling industry or making of paper bags which were predominantly used in most of the mom & pop stores. Because of the low tearing strength of paper, consumers do not prefer paper bags, especially the ones made from recycled paper.

Normal paper, depending on the thickness can be a strong material but it is brittle in nature with poor tearing strength. There have been many developments that have made possible stronger paper materials but invariably they fall under the special category with high price tag beyond the reach of many users like retailers and packaging industry. As far as food products are concerned paper has excellent barrier properties but use is limited because of its poor strength. In combination with other materials like aluminum, paper is still preferred for making laminated pouches for packing many food products. Waxed, glassine, Kraft and grease proof papers are still in use in industries like meat, dairy, frozen vegetables, baked goods, butter, ice cream, etc as they have high resistance to fat, oil and grease and are capable of high flavor retention. Multilayer sacks with 2-6 plies of paper also are extensively used. The corrugated cartons which happen to be the work horse for the transportation of almost all industrial products are based on Kraft paper.

In a recent development in Holland, paper materials with tear strength better than cast iron was found possible by subtle innovation in the paper making process. Called the nano paper, the process involves treating the wood pulp the basic raw material,with enzymes and pulverizing to generate fibers with 10 u diameter which were then swirled into tangles that are 10-40 nanometer wide for making the paper. The web like structure created and the strong adherence between the fibers make the paper very strong with high resistance to tear. Obviously such developments will be covered by patents and how far they will be economical remains to be seen.

Food packing is a delicate balance between the imperative to protect the contents from damage, physical, chemical and vectorial, and the compelling need to make it consumer friendly so that contents are easily accessible. Whether the new 'iron' paper is amenable to the two critical needs will decide its ultimate use by the industry.

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