2736 



CHAPTER 23 

 Fiberboards 



CONTENTS 



Page 



23-1 INTRODUCTION 2740 



23-2 THE INDUSTRY 2741 



INSULATION BOARD 2741 



Exterior 2742 



Interior 2744 



Industrial products 2744 



HARDBOARD 2744 



MEDIUM-DENSITY FIBERBOARD (MDF-DRY) 2744 



23-3 SOME CHEMICAL ASPECTS 2746 



23-4 RAW MATERIAL 2747 



SPECIES 2747 



WOOD DENSITY AND BOARD PROPERTIES 2748 



FIBER LENGTH 2748 



WOOD FURNISH 2751 



23-5 PREPARATION OF RAW MATERIAL 2751 



23-6 PULPING PROCESSES 2752 



PULP FREENESS 2754 



MASONITE PULPING PROCESS 2755 



The Masonite gun 2755 



Effect on wood 2756 



Yield 2757 



Pulp characteristics 2757 



DISK REFINING 2759 



Single- and double-disk refiners 2759 



Atmospheric disk refiners 2760 



Pressurized refining 2765 



Pulp consistency, plate design, and refiner selection . . . 2767 



PULP WASHERS AND SCREW PRESSES 2769 



