Case Study I – Work for International ClientsPosted by superadmin on Apr 16, 2013 in Case Study | 0 comments
We got a business inquiry for bread wrappers from East Africa. The brief was double side dip wax coated paper for wrapping bread loafs. This did not seem complicated as we had prior experience of supplying wax bread wrappers to Britannia Industries. We got an order for one container load of bread wrappers. We prepared the lot and sent it to the client. The client complained that the paper was tearing and not running properly on the automatic packaging machines. The situation was disastrous. A lot of money was at stake and there was a danger of losing not only money but a prospective regular customer.
We asked the client to send back samples of their existing wrappers so that we could analyze their samples. On examination of samples, the first thing we realized was that the paper was made of much longer fibers as compared to our base paper. Longer fiber meant that there was more entanglement of the fiber which gave the paper better resistance to shear and tear.
Tearing resistance characterises the toughness of papers with respect to the ability to absorb shocks. Fiber length and interfibre bonding are both important factors in tearing strength. Softwood pulp have longer fibre length while hardwood pulp have shorter fibre length.
In India, paper makers face a constant shortage of long fibre raw materials and hence the commonly available paper does not show high tensile strength. Cellulose fibers of Indian papers mostly coming from softwoods or agro based material or recycled paper and tend to have shorter lengths while papers procured from other parts of the world have long fibres and corresponding higher tear, tensile and wet web strengths.
We contacted our paper mill to give us a paper with longer fibre length as per the sample of the wax bread wrapper we had received. The mill supplied us with a new batch of paper. We made samples and sent them by courier. The feedback was that though the wrapper was better than last time but it was still not as good as the paper the client was procuring from elsewhere. We passed on the feedback to the paper mill who assured us that they had matched the strength of the bread wrapper sample we had given them.
We were apprehensive and confused. We got the raw paper from the mill before and after wax coating tested while also testing the East African samples for strength. The strength of the East African was per the Paper Mill findings, however we made a new discovery that after wax coating the strength of the mill paper got reduced. Thus, the paper mill was not wrong when it said that the raw paper it had produced afresh was of as high strength as wax coated paper from East Africa. The missing link to the problem was after wax coating paper was becoming weaker and hence strength of the raw paper had to matched rather than the wax coated wrapper. We immediately contacted the client and asked for a sample of base paper (unwaxed) from the client for analysis. The client was cooperative and managed to arrange the same for us.
To further understand this relation of fibre length affecting the tear and shear properties of paper we decided to do a bursting strength test on both paper samples (Indian and that from East Africa). The bursting strength of paper is a composite strength property that is principally affected by tensile strength and stretch-ability of fibre mesh within the paper. Normally, bursting strength relies on proportion, kind and amount of fibres available in the sheet, their preparation process, degree of beating and refining and use of additives. On testing the burst strength of the paper sample received the results showed that the East African paper sample had 50% higher burst strength to the Indian paper sample we had initially sent to the client.
We once again contacted our paper supplier and got in touch with the paper mill. This time our brief was more specific, we needed paper with longer fibre length and burst strength which was 50% higher. The paper mill analyzed the samples we had received and specially prepared a pulp blend for making this paper. Within a weeks time we received new samples. The burst factor which was achieved by the Paper Mill this time was now actually 10% higher than the base paper from East Africa. We new that our research and efforts have worked. The sample roll was prepared and sent to the client and approval was received. The client however wanted some further minor improvements such as whiteness of paper, but largely, after toiling for nearly a year, we managed to win the confidence of a client and create a long-term business opportunity.