Alkyl Ketene Dimer Wet End Hydrolysis in Alkaline Hardwood Furnish
Alkyl ketene dimer hydrolysis in alkaline hardwood stock converts active sizing wax into unreactive dialkyl ketone, raising chemical costs and felt deposits.
Alkaline Hardwood Furnish
Short-Fibre Base
Short-density deciduous wood pulp suspended in a mild alkaline aqueous suspension forms a foundational slurry for high-opacity printing stocks. Papermakers utilize alkaline hardwood furnish to establish structural smoothness and dimensional stability in uncoated freesheet grades. The slurry operates at a pH range of 7.5 to 8.5, accommodating calcium carbonate fillers without acid hydrolysis of cellulose chains.
Fiber length remains strictly bounded between 0.8 and 1.5 millimeters, defining the physical boundaries of this raw stock.
Chemical Mechanism
Fiber swelling occurs rapidly in mild alkaline liquor, increasing the total surface area available for hydrogen bonding during sheet formation. Refining actions cut and fibrillate short hardwood fibers to build internal bond strength without generating excessive fine particles that clog wire drainage. Calcium carbonate particles deposit within the wet web, acting as a bright whitening agent while reducing energy demand during press-section dewatering.
Excess swelling can lead to slow drainage on the Fourdrinier wire if beating parameters exceed standard web forming limits.
Sheet Properties
Uniform formation achieved with this furnish minimizes micro-variations in ink absorption across the paper sheet. Printed images display high tonal clarity because the dense short-fiber matrix limits lateral ink spreading. Lower tear strength compared to softwood pulps requires blending with long fibers for high-speed web offset applications.