DESCRIPTION

This invention concerns coating compositions, a method of coating and coated articles and substrates. The invention also concerns compositions that may be used as insulation material and products incorporating such insulation and compositions that may be used for moulding.

A comparatively recent development in the manufacture of materials for the building sector is that of chipboards comprising wood particles bound together with cement. This gives a board of great rigidity with a high resistance to fire. There are, however, several disadvantages with such chipboards in practical use. The material is hydroscopic being capable of absorbing 30% of its own weight in water. It has a natural balance level of 9% of water and loses strength if that water level is decreased. An architect calculating the weight of a structure including the board has to allow a very high safety margin. The cement content is alkaline and this effectively stops the application of acid cured systems. Conventional paints can lift off due to the variable moisture content, which may be high at the time of coating. Merely coating such boards with phenolic

resin cured with an acid catalyst does not alleviate these difficulties as the acid catalyst is counteracted by the alkaline substrate.

Furthermore, when cement fibre board is being manufactured the cement fines migrate to the surface, giving a finish which is not acceptable in some circumstances. In that case, it is the practice to machine the surfaces of the board, which is a costly procedure. One object of this invention is to provide a composition suitable for coating cement bound boards.

Another object of this invention is to provide a composition for coating cement based substrates generally. A further object of this invention is to provide a composition for producing insulating materials, especially for situations where low smoke, low toxic fume and low spread of flame characteristics are required. Yet further object of the invention is to provide a mouldable composition that preferably has low toxic fume emission, low smoke emission and low, preferably nil, flame spread under fire conditions.

It has now been surprisingly found, that adding cement to a non-acidic, preferably alkaline, phenolic resin and ester catalyst system can provide useful

materials .

According to the invention there is provided a composition comprising a non-acidic phenolic resin, an ester catalyst therefor and cement. The phenolic resin is preferably an aqueous alkaline resin, although a neutral phenolic resin emulsion may be an alternative.

Compositions according to the invention may include selections of various fillers, such as fly ash, fire resistant additives, such as frit mixtures

(CEEPREE), in which one is a devitrifying frit, and fibrous reinforcement such as glass fibre or ceramic or basalt fibres, possibly as chopped strands, according to the intended use of the composition. Preferably glass fibre used is treated to resist degradation in alkaline conditions.

The amount of cement included in the compositions of the invention will preferably be sufficient to take up substantially all of the water held by the phenolic resin, although other substances may be included in the compositions of the invention to take up some of the water, such as hydrated magnesium calcium carbonate. Typically the amount of cement used will be in the weight ratio of from 1:3 to 1:1 relative to the resin dispersion.

Typical fillers for compositions of the invention

include, finely divided particulate materials, such as fly ash, mica and., clays, and foamed or expanded materials, such as foamed or expanded waste glass (eg. PORAVER) , foamed kaolin, expanded clay (eg. LECA) , expanded fire clay grog powder and vermiculite. The type of filler chosen will depend on the end use of the composition and a close packed structure may be achieved by suitable mixing of filler sizes.

For enhancing fire resistance of compositions of the invention suitable additives may include intumescent materials, such as alumina trihydrate or hydrated magnesium calcium carbonate and combinations of frits (eg. CEEPREE).

When the compositions of the invention are to provide a top surface, a decorative, non-slip or hardwearing finish may be provided. In one case large grained silica sand and in other cases white hemispheres in ceramic and black anthracite specks as a mixture may be used in forming the top surface. Hardwearing and/or decorative powder materials may be added to the intended upper surface of a moulded product or coating, such as coloured glass frit say with a melt temperature of about 400 degrees C. Alternatively, materials such as carborundum powder, fibre or grit or silica sand may be used.

The decorative finish can be varied to suit

different environments and can give a non-slip walking surface, if required. Glass reinforcement can be applied as part of the process to give good deflection strength. Acid cured phenolic resins do not accept colouring, other than carbon black, without very rapid loss of colour. It is found that by using colourants formulated from metal oxides for colouring concrete products, the phenolic ester system can be tinted with a limited range of colours. Suitable colourants include titanium dioxide, zircon and manganese dioxide.

According to a first preferred embodiment of the invention there is provided a composition suitable for coating or protecting cement based substrates comprising a non-acidic, preferably alkaline, phenolic resin, an ester catalyst, cement and optionally additional water.

The present invention may also provide a method of coating _. or protecting cement based substrates comprising applying thereto a composition comprising a non-acidic, preferably alkaline, phenolic resin, an ester catalyst therefor, cement and optionally additional water.

The phenolic and ester combination can be used as a coating to decorate, renovate and protect concrete structures. Carbon dioxide, slightly acidic rain and chlorine ions present in urban atmospheres attack

concrete chemically, weakening its natural alkalinity. Gradually carbon dioxide penetrates to reinforcing bars and induces rust which swells to twice the volume of the bar and destroys the concrete from within. A building can be sprayed with the composition of the invention and glass reinforcement can be incorporated if required. A decorative finish can be applied in any suitable manner, such as of pebble dash. Alternatively the coating composition when dry can be painted, such as with a polypepoxide paint containing I.C.I. Ceepree fire barrier material.

The phenolic and ester mix is filled with cement. The water in the resin system cures the cement which is strengthened by the resin. This mix can be applied to the inside of a mould and be transferred during a concrete casting process, thus providing a prefinished casting.

According to a second preferred embodiment of the invention there is provided a mouldable composition comprising a non-acidic, preferably alkaline, phenolic resin, an aliphatic ester, cement, a filler having an average particle size of at least 0.5mm and optionally water, the composition when cured having a weight of at least 30kg/m ² at a thickness of 50mm. The fillers useful in the mouldable compositions of this invention may include waste glass material

preferably of a honeycomb or foamed type e.g. PORAVER (produced, by Dennert of West Germany) and foamed clays such as kaolin e.g. TECPRIL. It will be appreciated that other relatively large size fillers may be used in the compositions of the invention, provided that they are of sufficiently low density to give a light but strong moulded product with, of course, desirable fire resistant properties.

The aim of this invention is to take the alkaline resin and by using it as a binder to various additives arrive at strong, lightweight, mouldable material with good fire characteristics. Various additives may be included in the compositions of the invention towards achieving that aim. One of the preferred additiv.es is glass fibre chopped strand preferably treated to resist degradation in alkaline conditions, Pilkington's Semphil being an example. Small size particulate fillers may also be included in the compositions of the invention. Fly ash as a weight reducing material being an example thereof. Moulded products made from compositions of the invention when dry can be painted, such as with a polypepoxide paint containing I.C.I. Ceepree fire barrier material. The mouldable compositions of the invention may be used for producing a variety of products particularly

for the building industry. Examples of products that may e produced from mouldable compositions of the invention include suspended platform floor tiles, roof tiles, insulation blocks, fire door covers, sheet material for cladding or forming insulating laminates.

According to a third preferred embodiment of the -invention there is provided a composition for producing an insulating material comprising a non-acidic, preferably alkaline, phenolic resin, an ester catalyst therefor, cement and a filler of average particle size of at least 0.5mm, the material when cured having a weight less than 30Kg/m ^{2 at a} thickness of 50mm.

Suitable fillers for producing an insulation material include expanded or foamed fillers, such as kaolin prill.

The compositions of the invention may be used in making boards and sheets, including insulation boards.

The ester catalyst used in the invention is preferably an aliphatic ester, such as butaline diacetate or butyl lactone which act at varying speeds to produce gel and cure from seconds to thirty minutes. The time of cure can also be changed by varying the quality of hardener, or the temperature, or both.

A preferred aqueous alkaline phenolic resin for use in the present invention comprises an aqueous phenol formaldehyde resin in the molecular ratio of

approximately 1:2 containing an alkali, such as sodium hydroxide, potassium hydroxide or calcium hydroxide, in an amount less than 10 per cent, preferably at least 4 per cent, especially about '1.2 per cent. The resin preferably has a molecular weight such that the following specification is achieved. pH at 20 degrees C 11 to 12.5 B4 at 25 degrees C 30 to 48 sees Solid resin yield 100 minutes at 150 degrees C 41 to 45%

Free formaldehyde upto 1.5%

The alkaline phenolic resin includes an alkali, such as sodium hydroxide, potassium hydroxide or calcium hydroxide in its composition. A small percentage of urea and of brominated phosphate may be added as smoke, flame and afterglow inhibitors. A pregelled starch at

2% may be included to render the mix more adhesive.

About 0.1% of silane may be added to strengthen the resin top surface by some 15% when it is used as a decorative or walking surface by the addition of large grain multi-coloured sand.

The addition of cement in its widest sense to the catalysed phenolic eliminates the problem of synoresis.

The phenolic is composed of broadly 50% solids and 50% water, the addition of cement in the correct ratio for the cement to be cured by the water is a function of

common practice modified on occasions by the action of other fillers. A typical mix would be:- 100 parts by weight of phenolic 50 parts by weight of cement 12 parts by weight of ester catalyst

15 parts by weight of Ceepree (frit mix from ICI)

Although alkaline phenolic resin is produced as an aqueous dispersion of approximately 50:50 solids to water, the solids content can be increased upto say 97% by weight, i.e. to form a high solids concentrate.

Alternatively the base resin may be spray dried so that again water content is low. Either of these forms of resin may also be used in forming the compositions of the invention by mixing the resin in relatively dry form with other dry ingredients, of the composition and adding water and catalyst as a final operation.

Used in the context of a substrate which is alkaline and moisture laden, the compositions of the invention can achieve a penetration which gives a physical bond. One preferred method of application of the compositions involves the modification of a polyester resin spray machine to accept a catalyst ratio of between 10% and 30% by weight of the alkaline phenolic resin instead of the normal approximately 5%. The machine may be fitted with a glass roving chopping head. The glass is prepared for use in alkaline

conditions and is normally used in the manufacture of glass reinforced concrete. All aluminium parts of the machine are preferably replaced with stainless steel.

The resin and catalyst are mixed and sprayed, taking the chopped glass strand into the stream and depositing the mix onto the board. Each strand is encapsulated and delamination does not occur. One possible product made in this way is a suspended access floor tile based on a cement/woodchip board. The boards are preferably coated on both sides with a composition comprising alkaline phenolic resin, butyl lactone, Ceepree fire barrier material from I.C.I. (frit mixture) , alumina trihydrate as a smoke suppressant, colourant and zinc borate. The board is preferably put through calendar rolls to consolidate the mix.

Hardwearing and/or decorative powder materials may be added to the intended upper surface of the tile, such as coloured glass frit say with a melt temperature of about 400 degrees C. Alternatively, materials such as carborundum powder, fibre or grit or silica sand may be used.

The decorative finish can be varied to suit different environments and can give a non-slip walking surface, if required. Glass reinforcement can be applied as part of the process to give good deflection

strength.

One or more frits may be added in the same way to save wear on the mixing pumps. Powder components are preferably applied between the spray and calendar nip rollers at a point before complete gellation. The calendar can have a texture or pattern on the top roll which would transfer onto the resin surface before full cure.

The production of a completely encapsulated platform tile with detail and fine edges may be accomplished by completing the cure of the component as described by pressing in a heated mould at a suitable point during the process.

The alkaline resin and cement can be used to seal and coat cement bound fibre board giving a waterproof coating which is both physically and chemically bound to the surface.

Boards may be produced according to the invention based on cement as a filler. For example chipboard may be produced by mixing a composition of the invention with cement and woodchips and cured. Wetting agent, for example, sodium silicate may be included in the mixture along with possibly one or more of colourant, fire barrier material, for example mixed frits, and a substance to give off water on heating, such as alumina trihydrate or hydrated magnesium calcium carbonate.

Such a board may be used to make insulation boards by forming sandwiches thereof with layers of insulating material made in accordance with the present invention. Insulation boards may also be produced according to the invention from mixtures of alkaline phenolic resin/ester catalyst, cement and foamed or expanded material, such as clay prill or any other suitable foamed or expanded material. Fire and smoke retardant substances may also be included in the mixtures from which insulation boards are produced.

This invention will now be further described with reference to the following Examples and with reference to the accompanying drawings in which: Figure l is a section through a moulded product made in accordance with Example 12; and

Figure 2 is a section through a moulded product made in accordance with Example 19.

Example 1 A cement bound chipboard panel 600m x 600m x 25m was used to make a suspended access floor tile. The underside of the board was reinforced in order to meet standard load tests.

The edges of the board were chamfered to avoid binding when placed edge to edge. The tiles were passed under a spray and glass roving chopping head, on a

vacuum conveyor, butted as a continuous stream. The underside of the tile was placed uppermost and was sprayed with catalysed resin mix including entrained glass strand, made to the following formula:- 50 parts by weight Alkaline phenolic resin

7 parts by weight Butyl lactone 20 parts by weight Ceepree Fire Barrier material from ICI (mixture of low and high melting frits) 12 parts by weight Alumina trihydrate as a smoke suppressant 5 parts by weight Manganese dioxide as a colourant 3 parts by weight Zinc borate 30 parts by weight Cement

10 parts by weight water

The conveyor had stainless steel upstands protected by release agent. The sprayed resin was allowed to run down the chamfered edge of the board, where it was rolled in place by sprung, teflon coated rollers, which are scraped clean on the outside of the conveyor and mounted in gaps in the upstand. The board was then put through calendar rolls to consolidate the mix. The board which, at this point, has the underside and two edges coated, was sent through a tunnel oven with a temperature of 80 degrees C and a surface stream

of air. The conditions allow the moisture to be dispersed and the resin mix to cure. The board was then reversed and rotated through 90 degrees and sent through the system again to coat the top surface and the remaining two edges. On this occasion the glass spray was cut off and a powder depositing head used to give a coating of a hard wearing walking surface and decorative coloured finish. The powder used was a coloured glass frit with a melt temperature of 400 degrees C which would aid in a fire test, carborundum powder, fibre or grit or silica sand also be used.

The production of a completely encapsulated platform floor tile with detail and fine edges was accomplished by completing the cure of the component as described by pressing in a heated mould at a suitable point during the process.

Example 2

A coating method for a wall board made from cement bound woodchip is described. A 3 m x l.5 m board plus cutting allowance x 15 mm thickness was coated using an alkaline phenolic resin and ester mix with 20% by weight Ceepree fire barrier material and colourant. The mix was compounded by a continuous screw mixer made from stainless steel. The mixer was fed by hoppers and discharged into a curtain coater. A roller can also be used if required to

compact the mix. A warm air stream removed surplus moisture and completed the cure. The board was then turned over and the process was repeated for a balanced board. Example 3

The manufacture of an integral bonded insulation sandwich suitable for partitioning or ducting is described.

One face of a cement based woodchip board was coated and cured as in Example 1. The other face was coated and before cure had a mix made up of the following formula deposited on the uncured face: 20 parts by weight of a mixture of

55 parts by weight Alkaline phenolic resin

7 parts by weight Butyl lactone 12 parts by weight Alumina trihydrate 20 parts by weight Ceepree powder 3 parts by weight Zinc borate 30 parts by weight Cement

11 parts by weight water 80 parts Kaolin Prill 140 density foamed reclaimed bottle glass from 0.5mm to 8mm in diameter in a ratio to pack. The binding agent was mixed into the dry components using a continuous stainless steel mixer fed

by hoppers. The mix was then discharged onto the board through a reciprocating nozzle. The depth was controlled by a stainless steel scraper running on the upstanding side guards. A second coated board was then applied to the top face of the insulation mix and pressure applied via a series of nip rollers. The sandwich construction described was tested at over 1100 degrees C for over four hours without failure. This sandwich could be cut, drilled and screwed. Example 4

A cement filled coating mix was prepared according to the following formula:

50 parts by weight Alkaline phenolic resin 10 parts by weight Butyl lactone 35 parts by weight Cement

5 parts by weight Metal oxide colourant

The water in the resin system cured the cement which is strengthened by the resin. This mix can be applied to the inside of a mould and be transferred during a concrete casting process, thus providing a pre-finished casting.

Example 5 A cement filled phenolic resin and ester catalyst was used to bind woodchip into a chipboard according to the following formula.

20 parts by weight Alkaline Phenolic Resin

3 parts by weight Butyl Lactone 15 parts by weight Cement 10 parts by weigh Sodium Silicate 5 parts by weight Metal Oxide Colourant 32 parts by weight Woodchip

10 parts by weight Ceepree (frit mixture) 10 parts by weight Alumina Trihydrate

5 parts by weight water

The woodchip was treated with the sodium silicate as a wetting agent and the other components were then mixed with the woodchip. This was laid onto a steel tray and pressed with a heated platen at 80 degrees C for three minutes. After turning out the board was allowed to mature using synoresis as the source of the water to cure the cement.

Example 6 An insulation board was made using the Example 5 formula as the bottom and top layers of a sandwich with the insulating material from Example 3 deposited between them. The layers were laid onto a stainless steel conveyor, one above the other from three separate mixers and whilst still in the uncured state were compressed into a homogeneous board which can be cut and drilled.

Example 7 An insulation board was produced by mixing the following ingredients in the amounts stated:

50 parts by weight of alkaline phenolic resin 7 parts by weight of a slow curing ester 50 parts by weight of cement

50 parts by weight of foamed clay prill as supplied by Filtec Limited under the trade name

Tecpril at a density of 140gms per cu metre 15 parts by weight of Ceepree fire barrier material (mixed frits) 25 parts water The dry ingredients were first mixed by tumbling in a stainless steel cement mixture and the liquid alkaline resin, water and catalyst were then added. The mixture was poured into a flat tray made from stainless steel which was mounted on a vibrating table. The board was mixed, poured and part cured and within seven minutes was capable of being de oulded. The cure of the cement over a period of several hours in a warm room completed the manufacture.

It was found that the side of the board in contact with the mould surface was of good finish and was capable of accepting a paint coating.

It has been found that the addition of the alkaline phenolic and ester system to the mix during the manufacture of cement bound chip and fibre board has the effects of shortening cure time and cutting down the hydroscopic quality of the board.

In a further experiment two cement bound wood fibre boards made by Pyrok were placed parallel to each other standing on their long edges in a vertical disposition. The gap between the boards was 40mm and the boards were 10mm thickness x 2m x 3m. The boards were held in steel frames clamped by pneumatic cylinders. A mixture of insulation materials in the following ratio was blown between the two boards in the method used for core manufacture in the foundry trade. 100 parts by weight Phenolic resin

12 parts by weight Catalyst 400 litres by weight of Tecpril 100 parts by weight Cement 25 parts by weight Ceepree (mixed frit) 50 parts by weight water

50 parts by weight T3000 microspheres The phenolic and cement extended by the T300 microspheres, adhered to the inner faces of Pyrok board. The insulation board was therefore an integral, self supporting board with a hard surface capable of accepting screws and tapped bolts. The pyrok board can be painted using a polyepoxide paint containing Ceepree. This combination of materials has been tested to over 4 hours in a BS476 test for insulation and integrity. Example 8

A coating mix was prepared according to the

following formula:

100 parts by weight alkaline phenolic resin 12 parts by weight butyl lactone 50 parts by weight cement 5 parts by weight metal oxide colourant

10 parts by weight Filtec Ltd T45 extender (Fly ash) 15 parts by weight Ceepree (mixed frits) 25 parts by weight water This mix was applied to a substrate via a modified polyester spray machine with the aluminium parts replaced by stainless steel.

Example 9

The mixture as prepared in Example 8 was deposited on a concrete substrate but with the addition of a glass fibre chopping head dispensing Cemfil pre- treated strand. The mix was consolidated with a serrated metal roller.

Example 10 The mixtures prepared in Examples 8 and 9 were applied to separate block moulds after the application of P.V.A. release agent. Concrete was poured into the mould and when set the demoulded component exhibited a coloured surface, in one case reinforced. Example 11

Mixtures as detailed in Example 8 and then

Example 9 were applied via a reciprocating head mounted on a goal post and computer controlled into .a Pyrok Cement wood fibre board as it passed below on a conveyor belt. The spray machinery was ^' made from a polyester machine with the catalyst ratios altered to suit and the spray gun replaced with a broad nozzle machine as used in the spraying of concrete.

Example 12 A suspended platform floor tile was manufactured by taking two screw and barrel type glass reinforced concrete machines and using one to lay down the equivalent of a gel coat and the other the core material.

The procedure was that a modified polyester spray machine laid down a layer 10 (see Figure 1) of alkaline phenolic resin ester catalyst, cement, fly ash and chopped strand Cemfil glass. A layer 12 of a mix of PORAVER, alkaline phenolic resin, ester catalyst, cement and fly ash was deposited on top of the saturated glass mat. The spray machine then made another pass to lay down the glass 14 on top of the PORAVER mix. A gel coat 16 containing silica was then laid on the top of that layer. The male half of the tool was closed after PVA release agent had been applied. Within six minutes the moulded tile was ejected. The top surface was machined off to expose the silica and the component was

stacked to dry in a temperature controlled room. After cure of the cement, which can be quick cure cement, a coat 18 of clear polyepoxide Ceepree paint was applied as a sealer.

Examples 13 to 16 Ester -cured phenolic resin, whether alkaline (that is catalysed by sodium "hydroxide, potassium hydroxide or calcium hydroxide), or emulsions which are neutral, can suffer form shrinkage and cracking if not adequately filled. During the catalysing process the excess water is discarded and can be an embarrassment.

Some filler formula which have proved to pack the resin and stop these defects are as follows in parts by weight:

Example 13 Example 14

300 Cement 300 Ciment Fondu

500 Ultracarb 500 Ultracarb

300 Ceepree 300 Ceepree

200 Mica 300 Expanded fireclay

30 Volclay grog powder

700 Resin 700 Resin

300 H ₂ 0 300 H ₂ 0

160 Catalyst 160 Catalyst

Example 15 Example 16

150 Portland Cement 300 Ciment Fondu

150 Ciment Fondu (High 600 Ultracarb

Alumina Content) 300 Ceepree 500 Ultracarb 300 -Expanded fireclay 300 Ceepree grog powder 200 Mica 30 Raw fireclay 30 Volclay 800 Resin 800 Resin 350 H ₂ 0 350 H ₂ 0 180 Catalyst 180 Catalyst 100 Molasses

The size and synergy of each particle of these powders produce a packing effect in the resin and the water, including that in the resin, is taken up by the cement and Ultracarb as part of the setting process. Ultracarb is the trade name of hydrated magnesium calcium carbonate. Alumina trihydrate can be substituted for Ultracarb if the required H 0 and C ₀₂ emission is at the lower end of the temperature scale. A mixture of alumina trihydrate and Ultracarb produced more gasses at the lower end, followed _. by a further five stages of gaseous production, up to approximately 1000 degrees C.

In Example 15, the Ciment Fondu and Portland Cement act together to produce a very rapid set and with the resin/catalyst cure being tuneable from 30 seconds to 30 minutes, a cold moulding or coating material can be produced. If reaction time is too fast then molasses dissolved in a little of the water can be added to slow

the reaction down (see Example 16). However it is usually sufficient to choose a suitable ester catalyst. The formula of Example 16 can also be used with glass reinforcement at 300 parts by weight. The glass should be alkaline resistant, such as Cemfil.

The use of a mixture of Portland Cement and alumina, producing a quick set cement, such as Blue Hawk, can help the problem of ion exchange between Portland Cement and the alkaline phenolic which results in a loss of strength. The preferred resins have low sodium, potassium or calcium hydroxide, or are emulsions which help this problem. Ciment Fondu at a ratio of lOOgms with crushed expanded clay such as Leca at 300gms with resin at 800 millilitres or alternatively Leca at I350gms Ciment Fondu 500gms and resin 400gms, the water in the resin activating the cement, can be used as a high heat resisting mortar. The crushed clay can be replaced by a refractory aggregate such as Fireclay grog, sodium silicate glass crushed and ground to 150 to 200, and made non hydroscopic by resin coating can be used in the coating mix or the mortar to intumesce and give further protection.

The formulae of Examples 13 to 16 may be used as binders to an insulating material. The aggregates in that case can be Poraver (expanded waste glass) at varying sizes to give good packing at the ratio of 20-

25% resin/powder to 80-85% aggregate. Another suitable aggregate is an expanded clay such as Leca in varying sizes or expanded Kaolin clay in the form of prill. A successful formula which has been indicatively tested gives four hours on BS 476 part 8 at 40mm thick between two 10mm containing cement boards and combines both Leca and Poraver. A old moulding polrusion or coating material and also be produced.

The alkaline nature of the resin, (or neutral but with alkaline fillers) means that it is possible to induce a foam by mechanical means. The procedure is to add 10 parts of detergent, such a Fairy Liquid, to 100 parts of water extracted from the formula. This mix is beaten vigorously until all the water is taken up. The molasses and water mix, if used, is then added. The resin is then thoroughly mixed in and all powders added. A specific gravity of 0.7 can be achieved and maintained with the aggregate .mixed in.

The aggregates can be of expanded foamed clay such as Leca, expanded fireclay grog, kaolin prill, Vermiculite etc. All have a foamed or expanded construction and a specific gravity lower than water.

An alternative aggregate material is foamed waste bottle glass, such as Poraver, produced by Dennert in West Germany. Typical formulae in parts by weight would be:

Example 17

300 Cement 500 Ultracarb 300 Ceepree 200 Mica 30 Volclay

700 Resin 300 H ₂ 0 160 Catalyst 2000 Leca 5mm to 10mm 300 Poraver mixed 0 - 0.5mm

1 - 2mm

2 - 4mm Example 18

300 Ciment Fondu 600 Ultracarb

300 Ceepree

300 Expanded Fireclay grog powder

30 Raw Fireclay

800 Resin 350 H ₂ 0

180 Catalyst

300 EFG 0-2mm

400 EFG 2-5mm

700 EFG 5-10mm 500 Poraver 4-8mm

Example 19

When phenolic resin has powder components added, typically as follows:-

Partially hydrated magnesium calcium carbonate (Ultracarb) at about 2 micron. Glass frits about 70 micron (Ceepree) .

Mica at about 38 micron. Volclay at about.20 micron. Cement at more than 90 micron.

Then a viscous liquid is formed which, when catalysed, can be used to bind together aggregates of different sizes and composition. The resin does not shrink or crack, being filled by the varyingly sized powder particles and the excess water taken up in chemical reaction. One of the aggregates which can be used successfully is vermiculite in the expanded form.

It is possible to make a strong fire resistant board using this combination of materials. The phenolic resin and powder components without aggregates make a good adhesive which can be used to adhere many facing boards onto a lightweight aggregate filled fire insulation panel. Typically foamed glass beads (Poraver) foamed clay (Leca) and/or expanded fire clay grog.

A composite board was fabricated as follows (see Figure 2) :- 1. A thin sheet (20) of dimpled stainless steel sheet, painted mild steel, galvanised steel, or

painted rigidised aluminium, or similar sheet is placed as- front face in the bottom half of a sheet mould, then duplicated as the top sheet (22) at the end of the process. 2. A rigid sheet of fire resistant board (24) is adhered to the metal facing using the phenolic and' powders . as an adhesive. The board could be calcium carbonate, mineral fibre or vermiculite bound with the phenolic and resin mix into a board made in the mould by casting a layer, or spraying, using concrete applicators.

3. A lightweight core (26) of phenolic, powders, and aggregate is then applied and the process completed by the addition of a top board (28) the same as board (24) and metal cladding (22), if the latter is required.

4. Light pressure and vibration are sufficient to expel air and keep the laminate stable, whilst the catalyst acts. The resultant board, particularly the vermiculite and fire insulation sandwich, is a strong lightweight heat barrier which can resist fire up to four hours and beyond with no loss of integrity or insulation. No shrinkage has been observed. Example 20

An insulation material was prepared as follows.

200g of water was mixed with lOg of liquid detergent in a mixing container. 600g of Alkaline phenolic resin was mixed in a further lOOg of water used to wash remnant of phenolic resin into the mixing container. 'With that was mixed a pre-mixed powder of 200g cement, 500g Ultracarb, 200g mica, 70g Ceepree and 20g volclay. Then pre-mixed aggregate consisting of 500g Poraver (equal volumes of 0.5 to 1mm, l-2mm and 2-4mm and lOOg of 2-4mm) and 800g Leca (3mm-10mm) was added and mixed in followed by 80g of ester catalyst.

The resultant mixture was poured into a mould and allowed to set (5 minutes).