NZ333778A

NZ333778A - Fire resistant panels and doors using fly ash casting plaster and water

Info

Publication number: NZ333778A
Application number: NZ33377899A
Authority: NZ
Inventors: Jonathan Wexler
Original assignee: Tyco Building Products Pty Ltd
Priority date: 1998-01-19
Filing date: 1999-01-18
Publication date: 1999-10-28
Also published as: AUPP138298A0

Description

<div class="application article clearfix" id="description"> New Zealand No 333778 International No PCT/ TO BE ENTERED AFTER ACCEPTANCE AND PUBLICATION Priority dates 19 01 1998, Complete Specification Filed 18 01 1999 Classification (6) E06B5/16, C04B14/00 Publication date 28 October 1999 Journal No 1445 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION Title of Invention Fire lesistant panels and doors and methods for their production Name, address and nationality of applicant(s) as in international application form. TYCO BUILDING PRODUCTS PTY LIMITED, an Australian company of 21-25 Mitchell Road, Brookvale, New South Wales 2100, Australia THIS INVENTION relates to panels and doors and, in particular, to fire resistant panels and doors and apparatus and methods for their production It is well known to use fire resistant doors to limit the spread of flames in a building fire and to provide protected exit paths for occupants Building codes specify the level of fire resistance required in a particular type of construction For example, the Building Code of Australia specifies fire resistant doors be installed in buildings where the level of fire resistance required may vary as a result of the conditions likely to be met in a specific type of construction The level of fire resistance is measured by the duration of a period of resistance and is commonly specified as 30, 60, 90, 120, 180 or 240 minutes, depending on service requirements Fire resistance performance is normally determined by exposure, of a full size prototype door set, to fire from a test furnace in the laboratory of an approved testing authority in accordance with specified testing procedures During the course of such procedure in Australia, the furnace temperature is raised from the ambient starting temperature, say 25°C, through 850°C at 30 minutes, 950°C at 60 minutes, 1050°C at 120 minutes, and then through to 1150°C at 240 minutes Whatever the specified fire resistance period, the door leaf, when subjected to fire exposure at either of its major faces, is required not to exhibit any line of sight perforations through the body of the leaf or separations between edges of the leaf and surrounding frame, through which fire may be deemed to pass Essential properties required to achieve this performance include low-linear shrinkage under fire conditions coupled with a high degree of stability against heat-induced deflection perpendicular to the plane of the door leaf Additional test performance requirements are for no flaming to occur at the unexposed face of the door assembly, and for temperature rises measured at five positions on the unexposed face of the door leaf not to exceed an average of 140°C within the first 30 minutes of the test cycle time It is known to fabricate fire resisting doors using various core materials of bonded heat-resisting matrix composition which, in turn, may be combined with specially shaped metal plates or edge pieces, wooden edge frames, and/or lock area inserts capable of accepting fastenings for hinges, locks, closures or other items of door furniture Decorative facings of plywood, fibreboard, metal sheet, laminate, etc , are normally adhered to the major faces of the core Typical examples are referred to in Australian Patent Nos 538681 and 591 637 by the present inventor From the late 1970's, there occurred a transition from asbestos containing core materials of laminated or composite construction to non-asbestos containing cores of monolithic construction Those now commonly in service in Australia include compression-bonded exfoliated vermiculite/clay/alkali silicate, compression-bonded rockwool synthetic resin, and individual gravity cast mouldings of gypsum/lightweight filler such as perlite To meet handling weight limitations, the formed monolithic door cores are required to have a bulk density preferably not exceeding about 550kg/m3, giving a maximum core weight of about 35kg for a standard sized door Core formulae made to this low density need relatively high levels of inclusion of ultra lightweight components such as exfoliated vermiculite, perlite, vitreous microspheres, mineral fibres, etc , all of which are relatively expensive compared to the cost of inorganic binders such as sodium silicate, calcium silicate, calcium aluminate or calcium sulphate (Gypsum) In an effort to avoid or mitigate the cost of these ultra lightweight aggregates, there have been past attempts to produce fire door cores where low bulk density is achieved by introducing gas or air bubbles into hydraulic cement mixtures While this is a well-proved and viable technique for many types of cement and gypsum-based products having relatively thick cross-sections, it has been found when attempting to produce large thin panels, such as fire door cores of typical size, 2000mm height x 800mm width and maximum thickness of about 40mm with a desired bulk density of around 500kg/m3, such panels whether from a cement composition or from unmodified gypsum were found to perform inadequately under fire conditions so that necessary test approvals could not be obtained In respect of lightweight foamed gypsum composition panels, deficiencies encountered are 1) excessive deflections of a door leaf under fire conditions leading to premature integrity failure by separation of door leaf portions from the adjacent frame member, and 2) excessive linear shrinkage of a leaf leading to premature integrity failure by gapping between the edges of the panel and surrounding door frames Similar problems were encountered in the fire testing of door panels based upon calcium silicate and calcium aluminate cement binders, with fire-induced deflections of somewhat larger order and different time/directional disposition being encountered Further difficulties were encountered with pre-existing lightweight foamed gypsum and non-autoclave cured silicate/aluminate cement composition core panel due to the low inherent mechanical strength giving rise to breakage with in-plant handling and transportation between manufacturing centres Problems were also encountered due to low surface pick strength giving insufficient tenacity of adhesive lamination of sheet facing material OBJECTS It is an object of the present invention to provide an alternative core material for a door or panel It is a preferred object of the invention to provide, an alternative core material for a fire resistant door It is a further preferred object to provide a door comprising a core of the alternative core material Other preferred objects will become apparent from the following description SUMMARY OF THE PRESENT INVENTION In one aspect, this invention resides in a method of manufacturing a core panel material for a composite door including the steps of combining fly ash, casting plaster and water, and setting the combined ingredients as a sheet Preferably, fly ash is provided in the range of 20-40% (w/w), casting plaster is provided in the range of 20-50% (w/w), and water is provided in the range of 23-35% (w/w) Fly ash is a known low cost extender to cements and concretes in building and road construction It is a refractory alumino-silicate powder composition which has mildly cementitious (pozzolanic) properties and is produced in large quantities as a by-product of electric power generation from black coal It is readily and cheaply available in areas where such power generation occurs The present inventor has found that fly ash can be incorporated in major proportions into low-density gypsum composition door core formulations to greatly improve flexural strength and residual hardness upon exposure to fire when compared to that of unmodified gypsum plaster, which normally weakens substantially when dehydrating under fire conditions The presence of fly ash also reduces the amount of linear shrinkage and deflection transverse to the plane of a panel under fire test conditions It has been found that these hot-fired strength and thermal deflection properties further improve with the addition of small amounts of glass or other fibre reinforcement and also with a water-based adhesion promoter such as acrylic or other synthetic resin emulsion which serves to anchor the reinforcement fibres within the lightweight core matrix and also improves the strength of surface adhesion to external facing materials Preferably, dispersed gas voids are incorporated in the mixture These voids may be incorporated by a mechanical foam generation and/or chemical foam generation A suitable procedure for mechanical foaming is to mix a proportion of the core mix formula water component with a wetting agent and pass it simultaneously with air through a foam-generating nozzle or similar device to form a stabilized froth, which is subsequently mixed in with the remainder of the core mix ingredients In addition or alternatively, dispersed gas voids can be incorporated by chemical foam generation A suitable procedure is to add to the mix a blowing agent and a decomposition catalyst A suitable blowing agent is commercial hydrogen peroxide solution, eg , in the range of 0 30-0 70% (w/w) Suitable decomposition catalysts include manganese dioxide, eg , in the range of 0 0-0 20% (w/w) and potassium permanganate When using chemical foaming methods, a further step may be undertaken for control and stabilization of foam-generation by the incorporation of liquid viscosity thickeners, such as selected cellulose esters, acrylic resin compounds or similar proprietary agents Optionally, small amounts of fibre reinforcement may be added to the mixture to improve the hot fired strength and thermal deflection properties of the panel Suitably, the fibre reinforcement consists of the addition of small amounts of glass, refractory mineral or synthetic resin fibre up to a level of 2% (w/w), but preferably around 0 80% Preferably, a water-based adhesion promoter is added to the combination Suitably, such adhesion promoter is acrylic or other synthetic resin emulsion A suitable range of the water-based adhesion promoter is up to 10% (w/w) However, this range may vary with the nature of the adhesion promoter which can come in a large range of different types and strengths In a second aspect, the present invention resides in panel forming means Suitably, the panel forming means may comprise a continuous horizontal moving belt with edge guides capable of retaining the lateral spread of core mixture Preferably, the edge guides are adjustable to allow variation of the width of panel produced Suitably, the volume rate of core mixture feed onto the belt is variable Preferably, the rate is co-ordinated with lineal belt speed to produce the desired thickness of mixture deposited on the belt 8 Homogeneity of texture may be improved by vibratory or other mechanical means Preferably, the uniformity of thickness is further controlled by passage through mechanical doctor, blade or roller devices Preferably, the belt is of suitable length to allow adequate hardness setting of the panel material to allow handling Alternatively, the panel forming equipment may comprise individual panel moulds After setting of the gypsum component of the panel, the core panel contains free water which is preferably substantially removed The water can be removed by air drying under ambient conditions Alternatively, water removal may be assisted by microwave heating Preferably, the water is removed by forced air circulation drying at elevated temperature in an oven operating in a range of 50-100°C Preferably, backing means is applied to the belt surface and also to the top surface of the wet mixture combination to form a sandwich composition Suitably, the backing means is backing paper Alternatively, the backing means may be a film or foil material suitably treated or configured to allow subsequent desired exit of moisture vapour in the drying process In a third aspect, the present invention resides in a method of manufacturing a door leaf including a solid core manufactured according to the above method and including the further steps of applying at least one edge strip piece to the core, applying a facing of sheet material which substantially covers at least the core face Preferably, the edge strip pieces are timber Alternatively, the edge strip pieces may be metal or other suitable material, and/or the sheet material is plywood laminate Alternatively, the sheet material may be metal or other desired facing material In a fourth aspect, the present invention resides in a method for manufacturing a door including a door leaf manufactured according to the above and including the further step of attaching mounting means Preferably, the mounting means, in operation, receives locks, hinges, closer or other hardware such as head bolts, sequencing arm and panic bars To enable the invention to be fully understood, preferred embodiments will now be described with reference to the accompanying drawings, in which FIG 1 is a sectional view of a door leaf including the core panel of the invention, FIG 2 is a sectional view of a second embodiment of a door leaf, and FIG 3 is a schematic diagram of a continuous belt manufacturing system for a core panel 10 DETAILED DESCRIPTION OF THE DRAWINGS Referring to FIG 1, there is shown a sectional view of a door leaf 1 which includes a core 2 of the fire resistant material of the invention Facings 3, 4 of sheet material are adhesively attached to the core 2, and to the edge strip 7 Metal channels 5, may be applied to edges of door core, at the points of hardware attachment, or alternatively metal strips 6, may be inserted into the core to accept hardware screws, or a combination of both 5 and 6 may be used FIG 2 is a sectional view of a second embodiment of a door leaf 8, in which the two major faces 9, 10 of the core 11, are bonded to sheets of backing paper 12, 13 which, in turn, are adhered to facings of plywood 14, 15 In other embodiments, the facings may be of any appropriate sheet material FIG 3 is a schematic diagram of one method of construction of a core panel Wet core panel ingredients 1 6 are poured from a container 1 7 onto a conveyor belt assembly 18 which has opposed side walls 19 which stop the lateral flow of the panel mixture Although FIG 3 shows schematically a container pouring the mixture, a skilled addressee will know the method extends to an instantaneous mix of the ingredients through a continuous mixer of wet and dry ingredients with immediate deposition on the conveyor belt The distance between the side walls 19 is variable so that panels of different width can be manufactured 11 The thickness of the panels may be controlled by varying the speed of the conveyor belt 20 and/or varying the rate at which the ingredients 16 are poured onto the conveyor belt 20 The length of the conveyor belt assembly 18 is such that the core panel ingredients 16 which have been poured onto the moving conveyor belt 20 are adequately set by the time they reach the end of the conveyor belt assembly 18 so that they may be cut at a desired length by a cutting tool 21 The core panel 22 is then dried in an oven 23 at, for example, 50-100°C Example 1 An example of a core panel manufactured in accordance with this invention is described below INGREDIENT WEIGHT % Dry Ingredients Fly Ash 30 00 Casting Plaster 35 00 Glass Fibre 0 80 Hydroxy Methyl Cellulose 0 08 Manganese Dioxide 0 02 Wet Ingredients Water 28 60 Acrylic Resin Emulsion 4 85 Foaming Agents 0 15 12 Hydrogen Peroxide 0 50 The five dry ingredients are pre-blended in a suitable mixing apparatus The four liquid ingredients are then added to form a fluid slurry consistency With continued mixing, foam formation initiates and then proceeds for several minutes until complete A mix made in accordance with this formula will have a handling time of up to approximately 15 minutes before i.ydraulic set begins to initiate This time period can be modified by minor additions of accelerating chemicals such as sulphate salts of alkali and alkaline earth metals Alternatively, the time period may be extended by the addition of retarding chemical salts such as salts of citric acid or powdered animal protein such as keratin The initial fluidity of the mix can be modified, if desired, with the addition of a wetting agent such as a sulphonated lignin or naphthalene type At completion of the foaming process, the foam liquid batch is transferred by pump, pressunsation or gravity feed to panel forming equipment The mixture may be poured into 5-sided open cast tray moulds or pumped into 6-sided closed surface moulds whose interior surfaces have been suitably lined or otherwise prepared to allow clean release of the panel after completion of the setting process which may take from minutes to hours, depending on which process activators have been favoured The setting time for the above formula is normally of the order of 30-60 minutes 13 Example 2 Preferably, the core panel production is performed by a continuous mix of the ingredients (hereinbefore described in Example 1) which are then cast as a foaming slurry onto a horizontal moving belt. 5 The belt has a working width in excess of normal door panel widths, eg , say 1000mm or 1200mm and is provided with adjustable edge guides capable of retaining the lateral spread of core mix, thus controlling the width of panel material The volume rate of core mix feed is co-ordinated with lineal belt speed to produce the desired 10 thickness of deposit, eg , 25, 28 or 38mm Homogeneity of texture is improved by vibratory or other mechanical means and the uniformity of thickness may be further controlled by passage through mechanical doctor blade or roller devices (not shown) Production may be enhanced by the addition of backing 15 paper, film or foil material which is unwound onto the belt surface before addition of the mixture The edges of this material are formed into a C section with the major leg equal to the required thickness of the core and the minor leg is formed at right angles over the top surface of the core A further layer of backing paper, film or foil material is applied 2 0 to the top of the panel mix, and overlaps, and is adhered to the minor leg of the backing material already in place, to form an envelope with clean, dry outer faces which prevent fouling of machine parts by the wet mix A further layer of backing paper, film or foil material is applied to the top of the panel mix to form a sandwich with clean, dry outer 14 faces which prevent fouling of machine parts by the wet mix, The face liners can be made adherent to the mix upon setting so as to provide the resulting core panel with additional skin strength and surface protection. Incorporation of additional carbohydrate and resin emulsion adhesive ingredients into the mix are of advantage in maximising the adhesion of paper-faced linings to the hardened core material The moving belt method of production requires a primary conveyor length that results in sufficient retention time to allow hardness setting such that the continuously formed panel can be cut by sawing or chopping into predetermined lengths The cut panels may be then gathered and stored in suitable racking After setting through crystallisation of the gypsum content, the panel material contains approximately 20% by weight of uncombined water which needs to be substantially removed This can be accomplished by air drying under ambient temperatures It is preferably carried out, however, by force drying at elevated temperatures (eg , at 50-100°C) in an oven This may occur by batch operation with the panels arranged on racking or alternative drying may be on a continuous basis in line with the belt casting operation Conversion of the core panels into door leaves requires the addition of mounting points for locks, hinges, closer and other hardware such as headbolts, sequencing arms, panic bars and other features as required The hardware mounting points can be in the form of localised sheet metal plates extending over the faces or edges of the core panel 15 in required positions and secured by means of adhesive or mechanical fastenings Alternatively, the hardware mounting points may be provided by heavy cross-section edge frames (eg , 28mm x 28mm or 38mm x 38mm) of timber or preferred material as opposed to light edge strips (5-15mm x 28 or 38mm) which are used in combination with metal plate mountings. Selection between the alternatives may depend on the degree of fire resistance performance required from a finished door set Edge pieces whether of light or heavy section can be attached to the core by solvent or water-based adhesive It is necessary to apply edge strip pieces covering the edges of the core Commonly, the edge strip pieces are of timber or material having similar appearance and working properties Finally, facings of sheet material such as plywood, laminate or sheet metal are applied to cover the major core panel faces These sheet facings can be adhesively attached If required, the sheet facings may be applied with the assistance of mechanical pressing and heat activation for accelerated setting and improved surface appearance The preferred embodiments described herein are intended to illustrate the principles of the invention, but not to limit its scope Other embodiments and variations to the preferred embodiments may be evident to those skilled in the art, and may be made without departing from the spirit and scope of the invention For example, the invention may include aerated or foamed gypsum core material in the bulk density 16 range of 400-600Kg/M3 having admixture of light weight silica, silica/alumina, compound alkaline earth silicate or other inner mineral filler, reinforcement with rockwool, metal, polypropylene, acrylic or other artificial or natural fibre, and supplementary binding ingredients derived from vegetable starch, animal protein and other natural or synthetic resins such as rubber latex, butyl rubber, ethylene vinyl acetate, polyvinyl alcohol/acetate, styrene acrylic, styrene/butadiene, neoprene and like materials in forms compatible with aqueous systems The door leaf can be manufactured with alternative edging and facing material such as melamine, laminate, medium density fibreboard, sheet metal or similar materials and various combinations of the above with timber substrates Door sets manufactured in accordance with this invention may have their performance further enhanced by incorporation of hot and cold smoke sealing provisions, either at the margins of the door leaf or as inclusions to the matching frame members Smoke seals can take the form of bristle brush mountings, flexible extrusion profiles, intumescent strip compositions or combinations of any of these forms Various other changes and modifications may be made to the embodiments described and illustrated without departing from the present invention 17 What We Claim Is. 1 A method of producing a fire resistant panel including the steps of combining fly ash, casting plaster and water, and setting the combined ingredients as a sheet 2 A method of producing a fire resistant panel as claimed in </div>

Claims

<div class="application article clearfix printTableText" id="claims"> Claim 1 wherein the ingredients are combined in the following ranges fly ash - 20-40% (w/w), casting plaster - 20-50% (w/w), water - 23-35% (w/w) 3 A method of producing a fire resistant panel as claimed in

Claim 1 or
Claim 2, further including the steps of adding one or more of fibre reinforcement and at least one water-based adhesion promoter 4 A method of producing a fire resistant panel as claimed in
Claim 3 wherein the fibre reinforcement is one or more of glass fibre, mineral fibre or synthetic fibre in a range up to 2% (w/w) 18 5 A method as claimed in either of Claims 3 or 4 wherein the water-based adhesion promoter is one or more of an acrylic or other synthetic resin emulsion or carboh\'didte 6 A method as claimed in any one of the preceding claims, further incorporating the step of introducing dispersed gas voids into the mixture 7 A method as claimed in Claim 6 wherein the dispersed gas voids are introduced using a mechanical foam generation technique 8 A method as claimed in Claim 6 wherein the dispersed gas voids are introduced using a chemical foam generation technique 9 A method of producing a fire resistant panel including the steps of combining Fly Ash approximately 30% (w/w) Casting Plaster approximately 35% (w/w) Glass Fibre approximately 0 80% (w/w) Hydroxy Methyl Cellulose approximately 0 08% (w/w) Manganese Dioxide approximately 0 02% (w/w) 19 Water approximately 28 60% (w/w), Acrylic Resin Emulsion approximately 4 85% (w/w), Foaming Agents approximately 0 1 5% (w/w), Hydrogen Peroxide approximately 0 50% (w/w), and setting the combined ingredients 10 A method as claimed in any one of the preceding claims, further including the step of placing the combined ingredients in panel-forming means before setting the combined ingredients 11 A method as claimed in Claim 9 wherein the panel forming means includes a continuous horizontal moving belt with edge guides which are capable of retaining the lateral spread of the combined ingredients 12 A method as claimed in Claim 11 wherein the edge guides are adjustable to allow variation of the width of panel produced 13 A method as claimed in either of Claims 11 or Claim 12 wherein the rate of addition of combined ingredients onto the moving belt is co-ordinated with lineal belt speed to produce a 20 predetermined thickness of combined ingredients deposited on the belt 14 A method as claimed in any one of Claims 11 to 13, further comprising the step of 5 improving the homogeneity of the combined ingredients by applying vibratory means 15 A method according to any one of Claims 11 to 14, further comprising the step of passing the combined ingredients through one or more of mechanical doctor blade or roller devices 16 A method according to any one of Claims 11 to 15, wherein the belt is of suitable length to allow adequate hardness setting of the panel to permit handling 17 A method as claimed in Claim 10 wherein the panel forming means comprises individual panel 2 0 moulds 18 A method as claimed in any one of Claims 10 to 16, further incorporating the step of drying the panel 10 21 19 A method as claimed in Claim 18 wherein drying is carried out by forced air circulation at elevated temperature in an oven operating in the range of 50-100°C 5 20 A method as claimed in any one of Claims 11 to 19 wherein backing means is applied to one or more of a belt surface, a top surface, and at least one edge of the combined ingredients when wet 10 21 A method as claimed in Claim 20 wherein the backing means is one or more of backing paper, film or foil material 15 22 A fire resistant panel produced according to the method of any one of Claims 1 to 21 23 A fire resistant core for a door leaf produced according to the method of any one of Claims 1 to 21 20 24 A method of producing a fire resistant door leaf, including the steps of producing a core as claimed in Claim 23, applying at least one edge strip to the core, and 22 applying a facing of sheet material which substantially covers at least one core face 25 A method of producing a fire resistant door leaf as claimed 5 in Claim 24 wherein the at least one edge strip is selected from one or more of timber or metal 26 A method of producing a fire resistant door leaf as claimed 10 in either of Claim 24 or Claim 25 wherein the sheet material is selected from plywood laminate or metal 27 A method of producing a fire resistant door leaf as claimed in Claim 24, further including the step of attaching mounting means to the core 28 A method of producing a fire resistant door leaf substantially as herein described with reference to FIGS 1 and 3 or 20 FIGS 2 and 3 of the accompanying drawings DATED this fifteenth day of January 1999 TYCO BUILDING PRODUCTS PTY LIMITED By its Patent Attorneys FISHER ADAMS KELLY END OF CLAIMS </div>