GB1604809A - Manufacture of shaped articles - Google Patents

Description

(54) MANUFACTURE OF SHAPED ARTICLES (71) We, CAPE BOARDS & PANELS LIMITED, a British Company of Iver Lane, Cowley, Uxbridge, Middlesex UB8 2JQ, do hereby declare the invention, for which we pra that a patent may be granted to us, and the method by which it is to be performe, , to be particularly described in and by the following statement:- This invention relates to moulding compositions for the manufacture of shaped articles, and is primarily concerned with providing a novel composition from which fire-resistant and other shaped articles may be made. The invention also relates to a method for making the shaped articles and to the shaped articles themselves.

It is well known to manufacture fibre-reinforced shaped articles such as boards from various binder materials (e.g. plastics and cementitious binders) reinforced with various fibrous materials. It is, for example, known to reinforce polyester resin binder with glass fibres, and to reinforce Portland cement or calcium silicate with asbestos fibres.

We have described, in our Patent Specifications Nos. 1,404,001 and 1,498,966 non-asbestos moulding compositions in which excellent properties, as regards both strength and fire-resistance, are achieved when mica and/or vermiculite is/are incorporated in a mouldable mix comprising a water-settable binder, such as calcium silicate, Portland cement, aluminous cement or blast furnace slag cement together with a non-asbestos fibrous reinforcement. The fibrous reinforcement comprises, in the main, organic fibres which do not melt below 140"C, cellulose fibres being particularly suitable.We have ascertained that the presence of mica and/or vermiculite in these products modifies them to the extent that they show better fire-resisting properties than compositions not containing mica and/or vermiculite; and that they shrink very little in comparison when subjected to high temperatures.

We have now discovered that the presence of mica in other classes of fibrereinforced cementitious compounds produces compositions from which shaped articles having very advantageous properties may be manufactured.

In accordance with the present invention, a composition suitable for the manufacture of shaped articles comprises a calcium silicate binder (or materials necessary for the production thereof) and/or Portland cement, mica and inorganic fibrous reinforcing material, the composition being free of organic fibres.

Such a composition preferably consists of 70 to 85%, by weight based on the total solids content of the composition, of the calcium silicate and/or Portland cement binder; 10 to 20% mica, on the same basis; and 2 to 15% inorganic fibrous reinforcing material, on the same basis. The inorganic fibrous reinforcing material is suitably asbestos-free and preferably it comprises glass fibres (e.g. alkali-resistant glass fibres such as "Cemfil"-Trade Mark), mineral wool fibres such as rock wool or slag wool fibres, or metallic fibres such as steel fibres.

The compositions of the present invention may be formed into shape, e.g. into board-shape, using the techniques described in Patent Specifications Nos.

1,404,001 and 1,498,966. Thus they can be formed into shape on a Magnani machine, a Hatschek machine, a Fourdrinier machine or a simple de-watering press. They can also be formed into shape by other, less conventional methods, for example injection-, extrusion- and suction-forming, with or without fluidisation using super-plasticisers or high frequency vibration.

Whatever forming technique is used, the compositions of the invention will normally initially be formed into an aqueous slurry. The slurry will have its water content adjusted as desired (such may not be necessary when fluidisation techniques are used, since less water is required to form the initial slurry), after which the slurry is formed into shape and the binder caused to set. Whatever technique is used for the setting of the binder will depend upon the nature of the binder. For example, when the binder is Portland cement, the setting may be by aircuring or by steam heating followed by maturing. When the binder is a calcium silicate binder, setting may be achieved by an autoclaving technique.

The mica used in the compositions of the invention suitably has an average particle size (or flake diameter) of less than 2 mm. Preferably the particle size of the mica is such that at least 95% is of a particle size less than 0.6 mm. Particularly suitable grades of mica are muscovite, biotite and phlogopite (e.g. Suzorite-Trade Mark). The mica preferably has a bulk density of less than 500 kg/m3, most preferably less than 350 kg/m3.

The following Examples are given for the purpose of illustrating the invention, the contents of the various ingredients being specified as parts by weight.

Examples 1-3 Building boards were produced from the following compositions: Example I Example 2 Example 3 Mica 1S 15 15 Lime 40 37.5 41 Silica 40 37.5 41 Glass fibre ("Cemfil") 5 - Mineral fibre ("Rocksil" - 10 Trade Mark) Steel fibre - - 3 These mixes were formed into shape using low water-content systems, namely a spray-suction technique in the case of Example 1 and vibro-fluidisation techniques in the cases of Examples 2 and 3. The products after curing had good strength and fire-resisting properties, coupled with low shrinkage at high temperatures.

Examples 46 In a manner similar to that described in Examples I to 3, building boards were produced from the following compositions: Example 4 Example 5 Example 6 Mica 15 15 15 Portland cement 80 75 82 Glass fibre ("Cemfil") 5 Mineral fibre ("Rocksil") - 10 Steel fibre 3 - 3 Reference is directed to our copending Application No. 8036000 (Serial No.

1604810).

WHAT WE CLAIM IS: 1. A composition suitable for the production of shaped articles comprising a calcium silicate binder (or materials necessary for the formation thereof) and/or Portland cement, mica and inorganic fibrous reinforcing material, said composition being free of organic fibres.

2. A composition as claimed in claim 1 wherein the inorganic fibrous material comprises glass fibres, mineral wool fibres or metal fibres.

3. A composition as claimed in claim 1 or 2 consisting of (by weight based on the total solids content of the composition) 70 to 85% calcium silicate and/or Portland cement binder; 10 to 20% mica, 2 to 15% inorganic fibrous reinforcing material.

4. A composition as claimed in any of claims 1 to 3 wherein the mica has an average particle size of less than 2 mm.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (10)

1. **WARNING** start of CLMS field may overlap end of DESC **.

   example injection-, extrusion- and suction-forming, with or without fluidisation using super-plasticisers or high frequency vibration.

   Whatever forming technique is used, the compositions of the invention will normally initially be formed into an aqueous slurry. The slurry will have its water content adjusted as desired (such may not be necessary when fluidisation techniques are used, since less water is required to form the initial slurry), after which the slurry is formed into shape and the binder caused to set. Whatever technique is used for the setting of the binder will depend upon the nature of the binder. For example, when the binder is Portland cement, the setting may be by aircuring or by steam heating followed by maturing. When the binder is a calcium silicate binder, setting may be achieved by an autoclaving technique.

   The mica used in the compositions of the invention suitably has an average particle size (or flake diameter) of less than 2 mm. Preferably the particle size of the mica is such that at least 95% is of a particle size less than 0.6 mm. Particularly suitable grades of mica are muscovite, biotite and phlogopite (e.g. Suzorite-Trade Mark). The mica preferably has a bulk density of less than 500 kg/m3, most preferably less than 350 kg/m3.

   The following Examples are given for the purpose of illustrating the invention, the contents of the various ingredients being specified as parts by weight.

   Examples 1-3 Building boards were produced from the following compositions: Example I Example 2 Example 3 Mica 1S 15 15 Lime 40 37.5 41 Silica 40 37.5 41 Glass fibre ("Cemfil") 5 - Mineral fibre ("Rocksil" - 10 Trade Mark) Steel fibre - - 3 These mixes were formed into shape using low water-content systems, namely a spray-suction technique in the case of Example 1 and vibro-fluidisation techniques in the cases of Examples 2 and 3. The products after curing had good strength and fire-resisting properties, coupled with low shrinkage at high temperatures.

   Examples 46 In a manner similar to that described in Examples I to 3, building boards were produced from the following compositions: Example 4 Example 5 Example 6 Mica 15 15 15 Portland cement 80 75 82 Glass fibre ("Cemfil") 5 Mineral fibre ("Rocksil") - 10 Steel fibre 3 - 3 Reference is directed to our copending Application No. 8036000 (Serial No.

   1604810).

   WHAT WE CLAIM IS: 1. A composition suitable for the production of shaped articles comprising a calcium silicate binder (or materials necessary for the formation thereof) and/or Portland cement, mica and inorganic fibrous reinforcing material, said composition being free of organic fibres.
2. 2. A composition as claimed in claim 1 wherein the inorganic fibrous material comprises glass fibres, mineral wool fibres or metal fibres.
3. 3. A composition as claimed in claim 1 or 2 consisting of (by weight based on the total solids content of the composition) 70 to 85% calcium silicate and/or Portland cement binder; 10 to 20% mica, 2 to 15% inorganic fibrous reinforcing material.
4. 4. A composition as claimed in any of claims 1 to 3 wherein the mica has an average particle size of less than 2 mm.
5. 5. A composition as claimed in claim 4 wherein at least 95% of the mica has a

   particle size less than 0.6 mm.
6. 6. A composition as claimed in any of claims I to 5 wherein the mica is muscovite, biotite or phlogopite.
7. 7. A composition suitable for the production of shaped articles, substantially as described in any of the Examples.
8. 8. Shaped articles produced from a composition as claimed in any of claims 1 to 7.
9. 9. Shaped articles as claimed in claim 8, in the form of boards.
10. 10. A method for producing a shaped article comprising forming into shape an aqueous slurry of a composition as claimed in any of claims I to 7, removing excess water therefrom and causing or allowing the binder to set.