Paper is a widely used packaging material and is nowadays regaining importance. Paper exhibits dimensional changes as a result of changes in moisture content that, at times, can seriously limit the performance and usefulness of paper. Moisture-induced dimensional changes have a significant effect on the runnability of paper and paperboard in converting operations.
BS 5879 specifies a method of measuring the dimensional change of paper after immersion in water. This property should not be confused with hydro-expansivity.
The method described in BS 5879 is suitable for use with most kinds of paper. However, it may not be suitable for some papers, which soaking makes it extremely fragile or causes to curl excessively.
BS 5879 on dimensional changes of paper is useful for:
The measurement of dimensional changes in paper and board with changes in the ambient humidity is necessary for accurate control of printing and similar processes. Dimensional instability strongly influences the end-use performance of paper, primarily in high-speed converting processes.
BS 5879 discusses the development of a test method to measure the dimensional stability of paper. An essential requirement of the test is that the paper should not be under any load while wet; most papers are very weak when wet and an extremely small load is sufficient to stretch them.
BS 5879 provides you with guidance on the measurement of dimension change of paper and board. BS 5879 guidelines help you to ensure the quality and permanence of paper which influences usefulness and accurate printing processes.