GB2106922A - Mixture of vinylidene chloride copolymer and ceramic material and method of use thereof - Google Patents

Abstract

A coating or moulding composition comprises a mixture of ceramic particles and an aqueous vinylidene chloride copolymer emulsion. The composition can be applied to existing wall surfaces or used to make building panels and slips. These can be made relatively light in weight compared with conventional products. By use of particles of ceramics such as brick, stone, slate and marble, the compositions when set resemble conventional building materials, so that the compositions are useful in the rehabilitation and repair of existing buildings. The composition has the special advantage that it will bond to a damp surface. The composition can be used in combination with low density, low heat conductivity materials to provide panels and walls which are tough, light in weight, highly heat-insulating, fire-resistant and water-proof.

Description

SPECFICATION Mixture of synthetic resin and inorganic material and method of use thereof This invention relates to a composition comprising a mixture of a synthetic resin and a non-metallic, inorganic refractory material (herein called a ceramic) and to a method of using such a composition.

The invention stems from the need for a versatile composition which can be easily applied to a surface by brushing or spraying, and which hardens to form a solid material to build up a coating of the composition on the surface which has excellent properties of fire retardment and which can be made to resemble a conventional ceramic building material.

According to the present invention there is provided a composition comprising a mixture of ceramic particles and a resin which is an aqueous vinylidene chloride copolymer emulsion.

The vinylidene chloride monomer may represent at least 75% by weight of the total monomers from which the copolymer is derived, and preferably represents between 88% to 93% by weight of the total monomers.

When such a composition is applied to a surface and allowed to dry and harden, it possesses excellent properties of fire retardment. A special advantage of the present invention over previous propos als is that the compositions will set and bond to a damp surface. The fire retardment may be improved by including an additive such as 2-ethyl hexyl diphenyl phosphate, zinc borate, antimony oxide or alumina hydrate.

Preferably the ceramic particles are of similar sizes. One useful size for optimum waterproofing is 300 mesh (in the British Standard Sieve classification), but coarser mesh sizes are more economical in use of resin and can be employed where a lesser degree of waterproofing is acceptable e.g. particle sizes upto 1 to 2 mm.

The invention includes within its scope a method of applying the foregoing composition to a surface and allowing the composition to dry and harden to form a tough coating when set. The invention also includes a method of moulding the foregoing composition or alternatively applying the foregoing composition to a surface of a former which imparts a desired shape to the composition during setting and which is separated from the composition when set.

When set, the composition provides an excellent barrier two passage of liquid water. In addition, the set composition is extremely durable and has good thermal insulation.

The resin may be that sold by Scott Bader Co. Ltd., of Wellingborough, Northamptonshire, England, under one of the trade designations "Polidene 33-001", "Polidene 33-004" and "Polidene 33-075", "Polidene" being a registered trade mark. The last-mentioned resin may be used where greater viscosity of composition is desired. Calcium carbonate or silicate may be included in the composition to hasten drying thereof, and titanium dioxide can be included to whiten the composition.

The composition may be built up in a number of layers by successive applications, using for example a brush or spray gun to build up a thickness of from 2mm. to 3mm. or even greater thicknesses, should a very high degree of fire retardment be required.

Each layer is allowed to dry before a subsequent layer is applied thereto.

When Polidene 33-075 is used as the resin, the resulting composition has stronger bonding properties. Accordingly, where the surface to be coated is smooth, it is convenient to mix a composition including Polidene 33-075 with a composition including Polidene 33-001, with the proportion by weight of the 075 composition being between 10% and 50% of the total weight.

The copolymer component of the resin may comprise an acrylate or methacrylate or a mixture thereof. For example, it may comprise a mixture of methyl methacrylate and ethylacrylate, or it may comprise acrylonitrile with an acrylate or methacrylate. Other monomers may be used if desired, for example, vinyl chloride, styrene, vinyl acetate, acrylamide, acrylic acid and the like.

In addition, a plasticiser may be added to the copolymer.

The ceramic particulate material may be either manufactured specifically for use in the present invention or may comprise a material e.g. brick particles, or china waste, which is a by-product of another manner of manufacture.

For greater bulk and heat insulation, particles of organic material e.g. cork granules can be added to the composition e.g. in an amount equal in volume to the amount of ceramic particles.

Multi-layer coatings, of which one or more layers is of a composition according to the present invention and at least one other layer is a composition described in British Patent No. 1578736 may be built up to provide composite coatings having excellent properties of thermal insulation, resistance to flow of water vapour, fire retardment, and mechanical durability. Bonding between successive layers is improved by stippling the surface of each layer while it is setting.

A fungicide/bactericide such as "Acticide 50", "Thion" or "Algon" (trade marks) as supplied by Thor Chemicals of Margate, Kent may be added to all the compounds mentioned above.

Compositions in accordance with the invention can be used to make "slips" with brick, stone, slate or marble powder, the slips being largely indistinguishable from single pieces of brick, stone and marble of the same size as the manufactured slip.

The following is one example of the manufacture and use of such slips.

A suitable grade of brick, stone, or marble dust is mixed with a vinylidene chloride copolymer emulsion e.g. Scott Bader's 'Polidene' resins, Nos. 33.075, 33.001,33.004 blended in suitable proportions. The resulting compound can then be filled into a mould into which is first placed a piece of expanded wire mesh (one example is that sold under the trade mark "Expamet") which is slightly smaller than the dimensions of the mould. Glass fibre or nylon can provide an alternative mesh. This mesh acts as reinforce ment and two layers placed in opposing directions to each other will provide even stronger and more resilient reinforcing. A brick slip formed in such a manner may have a thickness of, say, 6mm. and can withstand heavy blows without shattering or even cracking.It is, of course, possible to make these slips without the inclusion of wire mesh.

Such a brick slip is to a greater or lesser degree impermeable to liquid water, but will permit the passage of water vapour. The degree of impermeability to liquid water may be controlled by the proportion and blend of resins used. The slip also possesses good fire retardment properties. The admixture of the previously named resins with brick, stone, slate or marble fillers does not appreciably alter the colour of these materials when the compounds dry out.

Brick or other slips formed in this manner can be made extremely light in weight and also space saving and will provide excellent cladding when fixed to suitable supports for the purpose of providing a decorative and waterproof traditional brick or other facade on, say, timber-frame or steel-frame dwellings.

The reinforcing mesh can provide the base for attaching mechanical fixings e.g. hooks, clips or such like, in orderto provide permanent fixing to the supports mentioned above. Suitable water-proof adhesives may also be usefully employed to fix the slips to their grounds. The fixing with adhesives e.g.

tile adhesives, is all that is required if the slips are being used for decorative/insulative purposes on the internal walls of dwellings.

Once the slips are placed in position and correct pattern on the walls or building panels, the joints can be pointed with a resin-based compound incorporating the above-mentioned resins with a suitable sand.

Such a compound has the advantage of not staining the brick or stone material unlike the traditional cement mortars.

Alternatively, there can be screeded onto the surface to which the slips are to be fixed, to a depth of around 5 to 10 mm, a composition of 80% sand or powdered Portland stone and 20% blended resins as mentioned above. The brick or other slips are then pressed into the wet resin material and excess material in the spaces between the slips is "linedoff" while still wet with a suitably shaped tool, to eliminate a separate pointing operation.

(1) A suitable formulation for brick, stone, marble or slate slips would be: 80% powdered ceramic material 20% resins specified above and blended in their correct proportions.

These perecentages may be altered to suit various applications.

To the above may be added a suitablefungicidel algacide, such as Thion or Algon, mentioned above.

For internal use only Scott Bader's PVA resin "Texicote" (trade mark) No. 03.004 may be incorporated in the compound to provide additional adhesion when applied directly to the wall plaster. This resin is stirred into the formulation given above, after it has been mixed but before it sets.

(2) A suitable "pointing mixture would be: 80% suitable sand 20% blended resins as above.

Various types of sand may be used including the waste obtained from brick kilns in order to achieve a desired colour.

A wide variety of colours, textures and "antique" finishes may be obtained by (a) introduction of colouring matter and/or mixing various colours of brick or stone powder together, (b) texturing by mechanical manipulation of the surface.

Another form of brick, stone, slate or marble slip may be manufactured by coating a substrate of a suitable insulation material e.g. a X" thickness insulation cork, with a composition according to the invention, to a depth of say 3 mm and allowing it to set. Alternatively one ortwo layers of expanded wire, glass fibre or nylon mesh can be stapled to the insulation materials on one surface and coated as above. The boards so formed, which can be coated on one or both sides, can be cut into suitable sizes to simulate bricks or another conventional ceramic building material. They can be fixed to a wall of a building and then the junctions between panels filled with wet brick or other material, or pointed, as necessary.

Compositions according to the invention can be used for restoring existing brick or stone work by simply brushing or spraying them on the work to be restored and re-pointing as previously described.

By using a powdered form of the brick or stone as used in the original construction the original appearance of the structure can be achieved.

A heat-insulating substrate suitable for forming a base for the slips may be formed by soaking paper, for example newsprint or cardboard, in warm water and reducing the paper to pulp. This pulp is then tumble-dried to extract the bulk of the water. A suitable blend of 'Polidene' resins is added and the resultant mixture is then placed in a mould, with application of heat and pressure in order to mould lightweight insulation boards, capabie of being sawn, screwed or nailed as required.

Layers of a composition in accordance with the invention may be alternated with layers of a composition comprising fine work granules and a resin as mentioned above, the latter composition taking the form of a builders' plaster-type material which can be applied by brush or spray.

A system whereby alternate layers of ceramic compound and cork compound is brushed or sprayed on to, say, steel work (girders) will provide protection and insulation against fire, and will thus prevent the steel from buckling. Suitable fire retardment materials such as antimony oxide or one of the other materials mentioned above may be added to both the ceramic and the cork compounds in order to provide increased protection. Additionally it is beneficial to first encapsulate the steel (girder) in a wire mesh cage in orderto provide a firms base for the first layer of sprayed material. The number of alternate ceramic/cork layers will be governed by the degree of protection required.

A composite building panel may be formed by using the previously mentioned resins e.g.

"Polidenes" Nos. 33-001,33-075, and 33-004, with the addition of finely powdered brick. Such a panel may be formed according to the following Examples.

The completed panels can be affixed externally to the existed dwelling, in such a manner as to form a sealed cavity of, say, 2" between the insulation at the back of the panel and the existing wall.

Passive solar panels can be incorporated in the south elevation, (and possibly the east and west) of the dwelling, thus warming the air 'trapped' in this cavity. This warm air can be ducted to the interior of the dwelling and circulated by means of low power, electrically driven fans. Heat storage material painted matt black can be positioned opposite these panels on the inside.

It is also envisaged that the existing window spaces could be incorporated in this system, in the form of double-glazed units having openings into the cavity described above. Both the solar panels and windows wou Id require to be equipped with shutters to cut down heat loss at night, and excessive heat during hot weather. Decorative panels such as described herein can also be used internally where practicable, with or without the insulation backing. Also the insulation materials could be other than cork such as Polystyrene or Polyurethane foam or example. However, the use of cork is preferred because in the event of fire it does not give rise to toxic fumes (unlike many other insulation materials).

Internal walls can be clad with simulated brick or stone panels herein described in order to provide excellent decorative, fire retardment and water vapour barrier properties, and having approximately one tenth of the weight of solid brick or stone, thus cutting down the requirement of expensive structu ral supports.

E)'AIViPLE Cork granules are mixed with a blend of "Polidenes" 33-001 and 33-075 in the proportion of equal quantities by weight to which mixture is finally added 5% by weight of Texicote No. 03-004 PVA resin for improved adhesion.

The above mixture is either screeded or sprayed on to one side of a plywood panel of suitable dimensions, say 3/8" thick, (or other materials which will form suitable supports for the completed panels), in order to form a lining which provides excellent heat insulation and which may be X" or greater in thickness. The application of moderate heat will assist in the rapid setting of the mixture, and care is taken to maintain the temperature always above 15 C so that the resin sets properly.

A piece of galvanised expanded metal mesh is affixed by means of suitable staples to the reverse side of the panel. A mixture of sharp sand and cork granules in approximiately equal quantities by volume, and bound with a blend of "Polidenes" 33-001 and 33-075 in equal quantities by weight, is then screeded on to the metallic mesh and allowed to set hard, with the application of moderate heat.

A further mixture of finely ground brick in powder form is then bound with resins 33-001 and 33-075 in the proportions of approximately 40% resin to 60% powdered brick, by weight. A mould which is constructed to simulate bonded brick-work is then placed over the set screed on the metal mesh, described above, and the mixture of brick powder plus resins is poured or screeded into these moulds to a depth of, say, 1/4". This mixture can be rapidly dried by applying moderate heat, and when nearly set the mould is lifted clear.

The spaces between the 'bricks' , can now be 'pointed' by extruding a mixture of, say, silica sand and the blend of resins previously described. A 'mastic gun' may be used for this purpose, which will greatly speed the 'pointing' procedure.

The completed composite panel now possesses the following qualities.

(1) Impervious to rain and wind, thus preventing the extreme of heat loss associated with wet bricks and mortar.

(2) Excellent simulation of various coloured and textured bricks.

(3) Excellent heat insulation and the added advantage that the panel is applied externally of the wall, rather than internally, with all the attendant disruption of occupants, as is calied for with other methods of heat insulating existing walls of buildings.

(4) Good mechanical durability.

Claims (26)

1. A composition comprising a mixture of ceramic particles and a resin which is an aqueous vinylidene chloride copolymer emulsion.

2. A composition as claimed in claim 1 wherein vinylidene chloride monomer represents between 28% and 93% by weight of the total monomers.

3. A composition as claimed in claim 1 or 2, wherein the composition includes a fire retardment additive.

4. A composition as claimed in claim 1,2 or 3, wherein the composition includes a plasticiser.

5. A composition as claimed in any one of the preceding claims wherein the composition includes a poiyvinylacetate resin for improving adhesion of the composition to a substrate.

6. A composition as claimed in any one of the preceding claims including particulate organic mate rial to improve the degree of heat insulation of which the composition is capable of providing.

7. A composition as claimed in claim 6, wherein the organic material is cork granules.

8. A composition as claimed in any one of the preceding claims, wherein the ceramic particles are of brick or stone or slate or marble.

9. A composition as claimed in any one of the preceding claims wherein the ceramic particles are of size which accords with British Standard Mesh size 300.

10. A method of using a composition as claimed in any one of the preceding claims comprising applying the composition to a surface and allowing the composition to dry and harden to form a tough coating when set.

11. A method according to claim 10, wherein the surface is an internal or external surface of an exteriorwall of a building.

12. A method according to claim 10, wherein the surface is on an internal wall of a building and a decorative finish is provided on the coating.

13. A method according to claim 10, wherein the surface is a building panel.

14. A method according to claim 10 or13, wherein the surface is on a heat-insulating material.

15. A method according to claim 10, wherein the surface is a mould surface.

16. A method according to any one of claims 10 to 15, wherein a mesh is secured to the surface before the composition applied thereof.

17. A method according to claim 16, wherein the mesh is an expanded metal mesh.

18. A method according to any one of claims 10 to 17, wherein the composition is applied to the surface as a layer and, before the composition has set, planar building components are set into the unset composition to provide a finished surface.

19. A method according to claim 18, wherein the building components are brick slips.

20. A slip composed of a composition which is a mixture of ceramic particles and a vinylidene chloride copolymer.

21. A slip as claimed in claim 20 which has been made in a mould.

22. A slip as claimed in claim 20 or 21, wherein the ceramic particles are of brick.

23. A building panel comprising a substrate coated with a composition which is a mixture of ceramic particles and a vinylidene chloride copolymer.

24. A building panel as claimed in claim 23, wherein the ceramic particles are of brick.

25. A building panel as claimed in claim 24, wherein the external surface of the coating is made to resemble a section of brickwork.

26. A building panel as claimed in claim 23, 24 or 25, wherein the substrate is of a composition which comprises pulped paper and vinylidene chloride copolymer.