AU664706B2 - Filler composition - Google Patents

Description

AUSTRALIA66 4 0 6 Patents Act 1990 COMPLETE SPECIFICATION For a Standard Patent

ORIGINAL

TO BE COMPLETED BY APPLICANT 4e*C tI I; I at at a itC t a La Name of Applicant: TERRANCE JOHN GARNER Actual Inventor: TERRANCE JOHN GARNER Address for Service: It I I I a a La at' a WRAY ASSOCIATES, Primary Industry House, 239 Adelaide Terrace, Perth, Western Australia, 6000.

Attorney code: WR Invention Title: "FILLER COMPOSITION" Details of Associated Provisional Application No: PK7724 The following statement is a full description of this invention, including the best method of performing it known to me:- 1 -2- This invention relates to a composition for use as a filler in the building and building renovation industry.

This invention has particular application in the finishing of internal walls, particularly the finishing of plaster board walls.

In a building construction where internal walls are formed by attaching sheets of plaster board to studs, joists, and the like, the join between the sheets has to be treated to obscure the join. It is the usual practice to use a two or three stage float and set technique to fill the join and when material has set the join is then sanded smooth for finishing as required by painting or wall papering.

Similar procedures are adopted to fill other imperfections in the plaster board, such as nail holes.

ItI~t S. 15 The two or three coat plastering is necessary for two reasons. The first reason is that often the first render coat is a gypsum (calcium sulphate) based plaster. When set, this tends to have a crystalline structure which when sanded becomes scratched, and is accordingly unsuitable as a final finish when sanded. This necessitates the use of finishing coats in order to leave a smooth finish on the wall. Additionally, the coating is necessarily a two or i Ithree step process due to shrinkage of the material when it sets. It is also desirable that the two or three step process take place over a period of time sufficient to enable each coat to dry, in order to prevent cracking or surface imperfections.

It is an object of the present invention to provide a composition which will allow the join between adjacent plaster sheets to be filled with a single application and provide a good finish when sanded.

1 II 3 It has been fof nd that if a quantity of expanded siliceous compound is added to the usual filling compositions shrinkage of the material when set can be substantially eliminated.

Thus in one form the invention resides in a composition for filling the join between adjacent sheets of plaster board and other imperfections in the plaster board with a single application comprising at least one filling material in powdered form which may be mixed with water and sets when dry characterised by the addition of a sufficient quantity of an expanded siliceous material whereby shrinkage or contraction of the composition on drying is substantially 1. :eliminated.

One expanded siliceous material suitable for the purposes of the present invention is in the form of microspheres or hollow ceramic spheres of silica and alumina such as that produced by combustion of coal in power generating stations and the like and recovered from the ash by washing.

.4, Generally the material is in the form of a fine white S 20 powder which is non volatile and non toxic having a specific gravity of the order of 0.7, a melting point of r the order of 1600 0 C and a particle size range of 12 to 315 C microns. Preferably the material has no detectable crystalline silica quartz when subjected to an x-ray diffraction scan. Suitable materials include these marketed under the trade mark "EXTENDOSPHERES", "PHILLITE" or "Q CELLS".

Another suitable expanded siliceous material suitable for the purposes of the present invention is expanded perlite which is obtained by heating a glass like form of volcanic lava known as perlite.

The amount of expanded siliceous material required will r~ depend on the nature of the filling compound and/or the hydraulic setting compound and is generally up to 40% by weight of the total composition. Most applications will require an amount of expanded siliceous material within the range of 20% to 40% by weight of the total composition, although some applications may require as little as Suitable hydraulic setting compounds comprise a cement preferably a white cement. Fillers which set when dry and are suitable for the purposes of the present invention 10 include clays.

SVarious additives are incorporated in the composition to improve the characteristics thereof such as inorganic fillers substantially insoluble in water selected from micronised mica, water retention agents such as hydrated aluminium silicate (kaolin), calcined hydrated silica (diatomite), and organic polymers such as a polyvinyl acetate redispersible polymer. The additives used and the amounts thereof may be varied to suit individual S requirements. Other additives may include anti-foaming 20 agents such as talc and fungicidal agents, and emulsifying agents such as methylcellulose.

The prirn y fi'..ling agent suitable for the purposes of the present invent-Ion is calcium carbonate preferably having a parti:le size within the range of 10 and 100 microns. A particle size distribution of 20% by weight of between and 25 microns and 80% by weight of between 50 and 100 microns is preferred.

The invention will be better understood by reference to the following description of one specific embodiment thereof, suitable for most applications.

The filling composition is made by blending 1.2kg of white S cement, 2.25kg of 75 microns calcium carbonate powder, 570g of 15 microns calcium carbonate powder, 150g of hydrated lime powder, 20g of diatomite clay powder, 80g of kaolin powdered clay, 100g of micronised mica, 1.2kg of 150 microns silica micro spheres, 450g of 100 to 25 microns silica micro spheres, 200g of powdered talc, 100g of an organic polymer in the form of a polyvinyl acetate redispersible polymer (sold under the trade mark "VINAPAS 526"), 22g of methyl cellulose and 12g of dextrin yellow.

The dry particulate mixture is then thoroughly blended to ensure thorough intermixing of all of the components thereof before packaging. In use, sixteen parts of the rendering composition are added to approximately five or six parts of water. The mixture is stirred until it reaches a smooth creamy and stiff mortar consistency. The 0 15 mixture is then allowed to stand for sufficient time to r.i allow the particles to be thoroughly wetted (generally from ten to thirty minutes) before it is lightly remixed. At :this stage, the mixture is ready for application.

The plaster board joints in the wall are taped according to 20 normal practice, and a single coat of the mix is applied Salong the join using a trowel. The applied compound is best trowelled flat, in order to minimise the effort 4 0required when sanding the finish, once the mixture has dried. Alternatively, the plaster board joint recesses can be filled using the mixture, which is either allowed to *firm before applying a top coat with the trowel, or trowelled straight over with the finishing coat.

When the treated area has been allowed to dry, which will occur within six to seven hours, depending upon ambient conditions, or preferably the following day, the surface is then sanded to a smooth finish. For best results, a one hundred and fifty grade open mesh paper on a sanding float jis recommended for the sanding. The finish is sufficiently i i 6 firm to be sandable after six to seven hours. Full cure generally requires twenty four hours.

The composition of this invention exhibits the advantage over the previously known three step render float and set compound, as the interior wall finishing operation on a building site, may be finished in one step instead of three steps. The result of this is that instead of taking at least seventy two hours as in the case of a three step render float and set operation, the same operation uiising the composition of the invention can be completed in twenty four hours.

Generally the composition of the present invention is sold as a dry powder which is mixed with the required quantity Sof water immediately prior to use. It may also be sold as a ready to use preparation by mixing a composition which does not include a reactive filling material with a I :quantity of water and packaging it in cans or other sealed containers.

The effectiveness of the one stage filling composition of 20 the present invention as compared with the three stage conventional filling composition is illustrated by tests C'0 conducted by the School of Civil Engineering Laboratories of Curtin University of Technology situated at Bentley, Western Australia, set out below: 1i. TEST SPECIMENS The test specimens are identified as follows:- One coat plasterboerd jointing cement on "CSR" board with paper tape One coat plasterboard joint cement on "CSR" board with easy tape 7 7 "Cl" One coat plasterboard jointing cement on "Boral" Board with paper tape "C2" One coat plasterboard jointing cement on "Boral" Board with easy tape "CSR" Board with paper tape GB100 base coat and X450 top coat applied as recommended by manufacturer "Boral" board with paper tape B300 base coat and top coat 550 applied as recommended by manufacturer "Boral" board with easy tape B300 base coat and top coat 550 applied as recommended by manufacturer "CSR" Board with easy tape GB100 base coat and X450 top coat applied as recommended by manufacturer Specimens A, B, Cl and C2 utilised the filling composition described in the specific example above. The remainder used filling composition recommended by the plaster board manufacturer.

2. METHOD OF TESTS Two arbitrary types of tests were conducted a tensile type (pull) test, and a bending type test.

Specimens were prepared in a draught free laboratory.

3. TEST RESULTS TENSILE TESTS Two identical specimens of each type were subjected to the tensile test, each being nominally 50mm wide and some 300mm long with a central joint. Specimens were clamped via their plaster board ends in a UPD 10 Universal testing machine, used on the 500 N range reading in 10N divisions. Loading rate was 250N/minute.

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-8- SPECIMEN THTCKNESS WIDTH ULTIMATE LOAD REFERENCE (mm) (mm) (N) A(1) 11 53 300 A(2) 11 49 260 B(1) 11.5 51 470 B(2) 11.5 54 490 C1(1) 10 51 270 C1(2) 10 48 230 C2(1) 10.5 49 430 C2(2) 10.5 50 490 D(1) 11 50 300 D(2) 11 49 280 E(1) 10 51 240 E(2) 10 51 310 F(1) 10 47 400 F(2) 10 51 420 G(1) 11.5 50 440 G(2) 11.5 47 440 BENDING TESTS S 20 Specimens were nominally 200mm wide and some 400mm long with a central joint, one from each type.

Specimens were simply supported on 25mm diameter rollers over a span of 300mm and loaded at third points with the open side of the joint uppermost. The test arrangement is shown in the accompanying diagrammatic drawing.

Load was applied gradually using a 360kN Avery Denison universal testing machine with load measured by electronic load cell.

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9 SPECIMEN REF WIDTH ULTIMATE TOTAL (mm) LOAD (N) A 208 1600 B 205 1500 C1 200 1400 C2 204 1650 D 205 1500 E 201 1400 F 206 1800 G 204 1150 4e 544c 454 SUMMARY OF TEST RESULTS In the tensile test the specimens utilising the filling composition of the present invention performed better than the other compositions tested whilst in the binding tests.

The results for the respective compositions were substantially equal.

A further embodiment comprises the composition as hereinbefore described, with the hydraulic setting constituents the cements and/or gypsum deleted therefrom, but mixed with the appropriate amount of water 20 to form a thick paste. This paste sets by evaporation and has all of the attributes of the embodiment hereinbefore described, except that the hydraulic setting qualities are absent. One advantage of this composition not containing the hydraulic setting constituents is that it can be made up and packaged in ready-to-use form such as a squeezable tube and sold from hardware outlets and the like for handyman use. Such embodiments are considered to fall within the scope of the appended claims.

It should be appreciated that the scope of the claims is I limited to the embodiments described herein.

Claims (18)

1. A filling composition for filling the join between adjacent sheets of plaster board and for filling other imperfections in plaster board comprising proportionately: 100 grams of a polyvinyl acetate redispersible polymer, 100 grams of an inorganic filler comprising micronised mica, S100 grams of water retention agent, 2820 grams of particulate calcium carbonate, and to 40% by weight of an expanded siliceous material. S.

2. A filling composition as claimed in claim 1 wherein I said water retention agent is selected from diatomite clay powder and kaolin clay powder.

3. A filling composition as claimed in claim 1 wherein said water retention agent comprises 20 grams of diatomite clay powder and 80 grams of kaolin cl 'y powder.

4. A filling compusition as claimed in any one of the preceding claims further including proportionately 150 grams of hydrated lime powder.

A filling composition as claimed in any one of the preceding claims further including proportionately 12 grams of dextrin yellow.

6. A filling composition as claimed in any one of the RA 4 preceding claims further including proportionately 22 grams Scf an emulsifying agent such as methyl cellulose.

Ni TO_ preceding claims further including proportionately 200 grams of an antifoaming agent such as talc.

8. A filling composition as claimed :I.n any one of the preceding claims wherein said particulate calcium carbonate has a particulate size lying between 10 and 100 microns.

9. A filling composition as claimed in claim 8 wherein said particulate calcium carbonate has a particle size distribution of 20% by weight between 10 and 25 microns and 80% by weight of between 50 and 100 microns.

10. A filling composition as claimed in any one of the preceding claims further including proportionately 1200 grams of a particulate hydraulic setting compound.

11, A filling composition as claimed in claim 10 wherein said hydraulic setting compound is cement.

12. A filling composition as claimed in claim 10 wherein said hydraulic setting compound is white cement. 4* t

13. A filling composition as claimed in any one of the preceding claims wherein said expanded siliceous material is selected from silica microspheres and expanded perlite.

14. A filling composition as claimed in claim 13 wherein said expanded siliceous material includes no detectable crystaline silica quartz.

A filling composition as claimed in any one of the preceding claims wherein said expanded siliceous material comprises 20% to 40% by weight thereof.

16. A spreadable filler paste comprising a filling ,'Acomposition as claimed in any one of claims 1 to 9, or 13 12- to 15, further including sufficient water to impart a workable paste like consistency.

17. A filling composition for filling the join between adjacent sheets of plaster board and other imperfections in the plaster board comprising:- white cement 1.200kg calcium carbonate powder (75 microns) 2.250kg calcium carbonate powder (15 microns) 0.570kg hydrated lime power 0.150kg diatomite clay powder 0.020kg kaolin powdered clay 0.080kg micronised mica 0.100kg silica microspheres (150 microns) 1.200kg silica microspheres (100-25 microns) 0.100kg powdered talc 0.200kg polyvinyl acetate redispersible polyn.er 0.100kg methyl cellulose 0.022kg dextrin yellow 0.012kg tit

18. A composition for filling the join between adjacent ,ttt e i sheets of plaster board and other imperfections in the plaster board substantially as herein described with reference to the description of the embodiment. Dated this TWENTY NINTH day of SEPTEMBER 1995. TERRANCE JOHN GARNER Applicant WRAY ASSOCIATES, Perth, Western Australia, Patent Attorneys for the Applicant. 1 k 16 Abstract A composition for use in the building or joinery industries intended for filling the join between adjacent sheets of plaster board or filling other imperfections in the plaster board. The filler may be utilised in a single application due to its low shrinkage characteristics. The filler comprises filling material in powdered form such as clays or limestone, a hydraulic setting compound such as a cement or plaster, and a sufficient quantity (typically in the range of 20% to 40%) of an expanded siliceous material such as microspheres or hollow ceramic spheres of silica and alumina, or expanded perlite. The filler constituents are blended with water and mixed to form a mortar like paste which may be applied to fill joins and imperfections, and left to harden. The set composition is readily sandable. t tA Ir I-I ,sa fo it ip bor. Tefle ayb tlsdi snl plcto J du toits ow hrinagecharcteistis. he flle