ACOUSTIC-EMISSION MONITORING OF LIGHTWEIGHT COATED PAPER

In this report, some results from acoustic emission (AE) monitoring Ca brief description of this test method can be found in the Appendix) o f paper specimens, loaded uniaxially in tension and with different typ es of coating, are given. Both base paper and coated base paper with v arying latex content in the coating layer have been studied. It is fou nd that the emission data, e.g. total events vs the sample tensile loa d, are subject to a large amount of scatter. Nevertheless, the results seem to indicate that the emission curves are translated to larger lo ads with increasing latex content in the coating layer. It may also be concluded that the increase of the load for onset of AE is larger goi ng from base paper to 10 parts by mass of latex per 100 parts by mass of pigment, than going from 10 to 20 parts of latex per 100 parts of p igment, indicating the existence of some saturation value for the late x content with regard to the onset of micro damaging. Some influence o n the amplitude distribution of varying latex content was observed. A cyclic loading scheme was considered in order to evaluate the so-calle d felicity ratio. However, these results did not show any definite dep endency on the latex content.