초록

A composite material comprises inorganic-bonded alkaline earth silicate fibers in which any bonding agents or fillers comprise low amounts of aluminum so that the composite material comprises less than 1% by weight aluminum expressed as Al2--O3.

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What is claimed is: 1. A composite material comprising colloidal silica-bonded alkaline earth silicate fibers in which any bonding agents or fillers comprise low amounts of alumina so that the composite material comprises less than 1% by weight aluminium expressed as Al2O3. 2. A composite materi

What is claimed is: 1. A composite material comprising colloidal silica-bonded alkaline earth silicate fibers in which any bonding agents or fillers comprise low amounts of alumina so that the composite material comprises less than 1% by weight aluminium expressed as Al2O3. 2. A composite material as claimed in claim 1 in which the composite material comprises less than 0. 5% by weight of aluminium expressed as Al2O3. 3. A composite material as claimed in claim 2 in which the composite material comprises less than 0. 1% by weight of aluminium expressed as Al2O3. 4. A composite material as claimed in claim 1 in which the composite material is essentially free of aluminium. 5. A composite material as claimed in claim 1 and comprising less than 1% by weight sodium expressed as Na2O. 6. A composite material as claimed in claim 5 and comprising less than 0.5% by weight sodium expressed as Na2O. 7. A composite material as claimed in claim 6 and comprising less than 0.1% by weight sodium expressed as Na2O. 8. A composite material as claimed in claim 1 in which the composite material is essentially free of sodium. 9. A composite material as claimed in claim 1 and comprising less than 0.5% by weight boron expressed as B2O3. 10. A composite material as claimed in claim 9 and comprising less than 0.1% by weight boron expressed as B2O3. 11. A composite material as claimed in claim 1 in which the alkaline earth silicate fibre is itself adapted for use without excessive shrinkage at temperatures in excess of 1200째 C. 12. A composite material as claimed in claim 1 in which the material is obtainable by vacuum forming from a slurry containing the following ingredients in weight %:--Alkaline earth metal silicate fibres 70-85% Colloidal silica (30% SiO2 by weight) 3-25% Organic binder 1-6% Filler 11-20%. 13. A composite material as claimed in claim 1 comprising:--Alkaline earth metal silicate fibres 70-90% Silica binder from colloidal silica (30% SiO2 by weight) 1-10% Organic binder 1-6% Filler 11-20%. 14. A composite material as claimed in claim 13 comprising:--Alkaline earth metal silicate fibres 77.3-87.2% Silica binder from colloidal silica (30% SiO2 by weight) 1.2-8.2% Organic binder 3.3-4.7% Filler 12.8-18%. 15. A composite material as claimed in claim 1 in which the material is a paper comprising:--Alkaline earth metal silicate fibre 90-95% Organic binder 5-10% Organic flocculants <1%. 16. A composite material as claimed in claim 15 in which the organic binder is an acrylic latex. 17. A composite material as claimed in claim 1 in which the material is a material obtained by vacuum forming from a slurry comprising the ingredients: Alkaline earth metal silicate fibre 60 parts by weight Colloidal silica (30% by weight SiO2) 12-14 parts by weight Starch 2.5 parts by weight based upon the total weight of solids added to the slurry; and in which the colloidal silica has a pH of less than 8. 18. A composite material comprising 4-12% by weight colloidal silica, 3-6.5% starch, balance alkaline earth silicate fibre, to total 100% based on the weight of composite material. 19. A composite material as claimed in claim 18 and comprising 4-9% by weight colloidal silica, 3.5-5% starch, balance alkaline earth silicate fibre, to total 100% based on the weight of composite material. 20. A composite material as claimed in claim 18 comprising about 6% colloidal silica. 21. A composite material as claimed in claim 1 in which the material is a material obtainable by vacuum forming from the ingredients:--White water component 50-80% by volume of 30% solids colloidal silica with 20-50% by volume water Alkaline earth metal silicate fibre 0.5-4% by weight of fibre, calculated as the weight of the fibre solids per weight of white water component and in which the colloidal silica has a pH of less than 8. 22. A composite material as claimed in claim 1 in which the material is a material obtainable by vacuum forming from the ingredients:--White water component 90-100% by volume of 30% solids colloidal silica with 10-0% by volume water Alkaline earth metal silicate fibre 2-3% by weight of fibre, calculated as the weight of the fibre solids per weight of white water component and in which the colloidal silica has a pH of less than 8. 23. A composite material as claimed in claim 21 and which comprises 15-30% by weight silica binder formed from colloidal silica, balance fibre. 24. A composite material as claimed in claim 17 in which the fibre is present in amounts comprising 0. 5-5% by weight of the water in the slurry. 25. A composite material as claimed in claim 1 in which the material is a material obtainable by vacuum forming from the ingredients White water component 65-100% by volume of 40% solids colloidal silica having a pH of less than 10 with 35-0% by volume water Alkaline earth metal silicate fibre 2-3% by weight of fibre, calculated as weight of fibre solids per weight of white water component wherein the sodium content of the colloidal silica is below 0. 1 wt %. 26. A composite material as claimed in claim 22 and which comprises 15-30% by weight colloidal silica, balance fibre.