Construction boarding material - formed by layers with differing filler contents to give inner light core and flanking outer surfaces of higher density

摘要

The construction board material, formed from a basic mass of at least ground paper with water and a mineral bonding agent, is formed in a number of layers, where at least one layer contains a filler or additive as a porous material or matter with a low specific gravity. The boarding is formed on a Hatschek or papermaking machine, in a succession of layers, each with variable filler contents. Pref. the boarding has a core with an additive, and a high density layer flanking both sides of the core, forming the outer surfaces of the board. The additive is a porous plastics, in particle form. The basic mass is used paper and/or used cardboard. The mineral bonding agent is cement and/or slaked lime and/or gypsum. The basic mass can also be given additives such as fibres and/or cellulose and/or additives of ground quartz or silica. The dry content of the basic mass is 15-20% used paper and/or cardboard or 15% used paper and 5% cellulose and/or used cardboard with the remainder of mineral bonding agent. The outer layers have a specific gravity of 1.5-1.8 and the core specific gravity is 0.4-1.2 USE/ADVANTAGE - The boarding is for construction applications, esp. as an insulation material. The boarding structure gives improved performance and better mfg. operation.