Accession Number : AD0712136

Title :   EFFECT OF REFINING ON COMPRESSIBILITY OF WET FIBRE PADS AND ON STRENGTH PROPERTIES OF AIR DRIED FIBRE BUILDING BOARDS. STUDIES IN PLANE PRESSING 4,

Corporate Author : SVENSKA TRAFORSKNINGSINSTITUTET STOCKHOLM

Personal Author(s) : Norberg,K. Gunnar ; Back,Ernst L.

Report Date : 19 MAR 1969

Pagination or Media Count : 11

Abstract : Masonite pulp was refined in one step at a consistency of 20% to pulp freeness values between 15 to 100 Defibrator seconds (DS) (780-645 CSF). These pulps were characterized by their fibre length distributions, their Hillbom fractions and the width of fibre bundles transverse to the fibre direction. At 15 DS less than 60% of the pulp occurred as free single fibres. Increased refining, especially between 60 to 100 DS, gave some network dislocations on plane pressing of the wet pads in the pressure range 3 to 100 kp/sq cm and thereby lowered the usable compression speed in the press. On the other hand, at 20C press temperature the static compressibility increased and therewith also the dewatering. There was no corresponding effect at 90C. The strength properties of the air dried sheets compared at densities between 0.3 to 0.9 g/cu cm were improved by increased refining up to 60 DS and especially in the range 15 to 30 DS. Above 60 Ds only the strength perpendicular to the plane of the sheet increased, while the rest of the strength parameters, especially the breaking elongation diminished. (Author)

Descriptors :   (*FIBERBOARD, MECHANICAL PROPERTIES), SHEETS, WOOD PULP, PROCESSING, PURIFICATION, SWEDEN

Subject Categories : Wood, Paper and Related Forestry Products

Distribution Statement : APPROVED FOR PUBLIC RELEASE