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TAPPI T 277
Macro stickies content in pulp: the “pick-up” method
TAPPI T 277 Macro stickies describes removing and preparation of a test specimen that can be analyzed for determining heat-set area and number of macro stickies in a specified amount of pulp screened. The method applies to a wide range of pulps, typically, recycled pulp. The standard practice does not quantify content of micro stickies.
Stickies testing procedures practiced currently in the industry vary enormously. This procedure provides a consistent format to separate for analysis stickies in a reasonable amount of time and with acceptable precision. Stickies present in a papermaking mill system can deposit on wires, felts, dryers, and calender stacks. Therefore, when carried onto the dry end, these stickies frequently cause sheet breaks and downtime for fabric cleaning. This method satisfactorily measures the macro stickies content, thus providing a means to determine the efficiency of stickies removal across various process modules in the recycle process and quantifying the final macro stickies content in the recycled pulp.
Pulp samples are screened using a laboratory screening device. The rejects from the screen are transferred to a black filter paper. A coated paper is placed on top of the filter paper, and then heated and pressed under controlled conditions. Once the coated paper is removed from the filter paper, the coating will be picked up by the stickies and create a contrast on the black filter paper, which readily allows the measurement of area and number of the heat-set stickies with an image analyzer or by hand using the transparent defect size measurement chart. The manufacturer and type of image analyzer and the parameters of measurement are not specified in this standard practice, but an example of an analysis procedure can be found in the appendix of this standard practice.
An initial sample size of 100g o.d. is recommended. If a pulp contains high stickies content, the sample size may be reduced.
SGS-IPS cannot sell or otherwise provide standards, specifications, or test procedures to third parties.