Mineral Fibre Panel and Process of Manufacture

Abstract

The invention relates to a process for manufacturing mineral fibre panels. The invention relates in particular to a process of manufacturing mineral fibre panels having high strength despite reduced binder content, thereby providing improved fire safety.

1 . A process for manufacturing a composite panel, comprising the steps of:
 (a) providing mineral fibres in an amount of 85 to 99 wt % of the total weight of starting materials;   (b) providing a binder in an amount of 1 to 15 wt % of the total weight of starting materials;   (c) mixing the binder with the mineral fibres;   (d) collecting the mixture of mineral fibres and binder onto a surface to form a fibre mat having an upper surface, a lower surface and an initial thickness;   (e) wetting the fibre mat with 0.01 to 3 wt % water based on the total weight of the starting materials; and   (f) compressing and curing the fibre mat to provide a consolidated composite panel having a final thickness.   
     
     
         2 . The process according to  claim 1 , wherein step (e) comprises spraying water onto the fibre mat from one or more spray nozzles. 
     
     
         3 . The process according to  claim 2 , wherein the water is sprayed:
 i) onto the upper surface of the fibre mat;   ii) onto the lower surface of the fibre mat; or   iii) onto the upper surface and the lower surface of the fibre mat.   
     
     
         4 . The process according to  claim 1 , wherein step (e) comprises wetting the fibre mat with 0.02 to 2 wt %, or 0.03 to 1.5 wt %, or 0.04 to 1 wt %, or 0.05 to 0.5 wt %, or 0.06 to 0.2 wt %, or 0.07 to 0.15 wt %, or 0.08 to 0.13 wt %, or 0.09 to 0.11 wt % water based on the total weight of the starting materials. 
     
     
         5 . The process according to  claim 1 , wherein the mineral fibres are provided in an amount of from 85 to 97 wt %, or from 88 to 96 wt %, or from 90 to 95 wt %, or from 91 to 94 wt %, or from 92 to 93 wt % based on the total weight of the starting materials, and/or
 wherein the binder is provided in an amount of from 3 to 15 wt %, or from 4 to 12 wt % or from 5 to 10 wt %, or from 6 to 9 wt %, or from 7 to 8 wt % of the total weight of starting materials, and/or   wherein the mineral fibres and binder together form at least 96 wt %, or at least 97 wt %, or at least 98 wt %, or at least 99 wt %, or substantially all of the total weight of the starting materials.   
     
     
         6 . The process according to  claim 1 , wherein the mass-weighted median fibre diameter of the mineral fibres is in the range from 1 to 20 μm, or from 2 to 10 μm, or from 3 to 5 μm, and/or
 wherein the mass-weighted median fibre length of the mineral fibres is in the range from 20 to 800 μm, or from 50 to 500 μm, or from 60 to 400 μm, or from 80 to 300 μm, or from 100 to 250 μm. 
 
     
     
         7 . The process according to  claim 1 , wherein the fibre mat comprises at least a first surface layer and a base layer, wherein the first surface layer forms the upper surface of the fibre mat, and wherein the first surface layer comprises a finer fraction of mineral fibres than the base layer. 
     
     
         8 . The process according to  claim 7 , wherein the fibre mat further comprises a second surface layer, wherein the second surface layer forms the lower surface of the fibre mat, and wherein the second surface layer comprises a finer fraction of mineral fibres than the base layer. 
     
     
         9 . The process according to  claim 1 , wherein step (f) comprises applying pressure to the fibre mat using at least one pair of opposed heated compression elements. 
     
     
         10 . The process according to  claim 1 , wherein step (f) comprises compressing the fibre mat for a predetermined compression residence time and at a curing temperature that is effective to cause curing of the binder,
 optionally wherein the compression residence time is in the range from 0.5 to 50 minutes, or from 1 to 10 minutes, or from 1.2 to 7 minutes, or from 1.5 to 6 minutes, or from 1.8 to 5 minutes, or from 2 to 4.5 minutes, or from 2 to 4 minutes, or from 2.2 to 3.8 minutes, or from 2.5 to 3.5 minutes, and/or   optionally wherein the curing temperature is in the range from 100 to 300° C., or from 120 to 280° C., or from 150 to 250° C.   
     
     
         11 . The process according to  claim 10 , wherein step (f) comprises an initial compression phase wherein the fibre mat is compressed to no more than 125%, or no more than 120%, or no more than 115%, or no more than 110%, or no more than 105% of the final thickness of the composite panel within the first 20% of the compression residence time, or wherein step (f) comprises an initial compression phase wherein the fibre mat is compressed to an intermediate thickness within a first portion of the compression residence time, wherein the first portion of the compression residence time begins at the start of the compression residence time, wherein the first portion of the compression residence time is from 1% to 25%, or from 4% to 20%, or from 5% to 19%, or from 6% to 18%, or from 7% to 17%, or from 8% to 16%, or from 9% to 14%, or from 10% to 14%, or from 11% to 13% of the compression residence time, and the intermediate thickness of the fibre mat is no more than 125%, or no more than 120%, or no more than 115%, or no more than 110%, or no more than 105% of the final thickness of the composite panel. 
     
     
         12 . The process according to  claim 11 , wherein the initial compression phase is followed by a final compression phase wherein the fibre mat is compressed to the final thickness of the composite panel. 
     
     
         13 . The process according to  claim 1 , wherein the final thickness of the composite panel is between 4 and 50 mm, or between 4 and 30 mm, or between 5 and 20 mm, or between 5 and 15 mm, or between 6 and 12 mm, and/or wherein the composite panel has a density in the range from 600 to 1600 kg/m 3 , or from 900 to 1550 kg/m 3 , or from 1000 to 1500 kg/m 3 , or from 1050 to 1450 kg/m 3 , or from 1100 to 1400 kg/m 3 , or from 1150 to 1350 kg/m 3 , or from 1175 to 1325 kg/m 3 . 
     
     
         14 . A composite panel obtainable by the process of  claim 1 . 
     
     
         15 . The composite panel according to  claim 14  having a loss-on-ignition (LOI) of from 3 to 15 wt %, or from 5 to 12 wt %, or from 6 to 10 wt %, or from 7 to 9 wt %, or from 7 to 8 wt %. 
     
     
         16 . The composite panel according to  claim 14 , having an initial bending strength in the range of 35 to 60 N/mm 2 , or from 35 to 55 N/mm 2 , or from 35 to 50 N/mm 2 , or from 35 to 45 N/mm 2 , or from 36 to 44 N/mm 2 , or from 37 to 43 N/mm 2 , or from 38 to 42 N/mm 2 . 
     
     
         17 . The composite panel according to  claim 14 , having an elastic modulus in the range of 4500 to 15,000 N/mm 2 , or from 5000 to 12,500 N/mm 2 , or from 5500 to 10,000 N/mm 2 , or from 6000 to 9000 N/mm 2 .