IS 1060 : Part 5 : Sec 4 : 2024/ISO 535 : 2023 Methods of Sampling and Test for Paper and Allied Products - Part 5 Methods of Test for Paper and Board - Section 4 Determination of Water Absorptiveness - Cobb Method

ICS 85.060

CHD 15

NATIONAL FOREWORD

This Indian Standard (Part 5/Sec 4) (First Revision) which is identical to ISO 535 : 2023 'Paper and board - Determination of water absorptiveness - Cobb method' issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on the recommendation of the Paper and its Products Sectional Committee and approval of the Chemical Division Council.

Paper and paperboard are fundamentally hygroscopic in nature which impacts their performance in various application such as packaging, printing and other similar usages. The cobb method helps in evaluating how well paper and paperboard can resist water penetration and accordingly exercise quality controls to get the desired quality of the paper and paperboard.

ISO has published test method standards related to paper, pulp and board under three broad categories namely 'paper, board and pulps', 'paper and board' and 'pulps'. Related Indian Standards published in IS 1060 (Parts 1, 2 and 3) 'Methods of sampling and test for paper and allied products' and IS 6213 series of standards published for 'Methods of test for pulps' are widely recognized and used in India. To maintain consistency with the prevailing international practices and to retain the existing test methods series, the committee responsible for formulating this standard decided to harmonize the methods of tests prescribed in IS 1060 series and IS 6213 series with those published by ISO and publish these adopted test methods standards in subsequent parts/ sections of IS 1060 series or IS 6213 series.

Other parts of IS 1060 series on 'Methods of sampling and test for paper and allied products' in which related Indian standards have been published are:

Part 4 Methods of test for paper, board and pulp

Part 6 Methods of test for paper

Part 5 Methods of test for paper and board

Part 7 Methods of test for board

This section of IS 1060 (Part 5) specifies a method for determining the water absorptiveness of paper and board, including corrugated fibreboard, under standard conditions. This document is not applicable for paper of grammage less than 50 g/m2 or embossed paper. It is not applicable for porous papers such as newsprint or papers such as blotting paper or other papers having a relatively high-water absorptiveness for which IS 1060 (Part 5/Sec 16)/ISO 8787 is more suitable. The other sections of IS 1060 (Part 5) are: