(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (19) World Intellectual Property Organization International Bureau (43) International Publication Date PCT (10) International Publication Number 13 September 2007 (13.09.2007) WO 2007/101855 A2 (51) International Patent Classification: (81) Designated States (unless otherwise indicated, for every C04B 28/14 (2006.01) C04B 41/47 (2006.01) kind of national protection available): AE, AG, AL, AM, C04B 20/10 (2006.01) C04B 41/48 (2006.01) AT,AU, AZ, BA, BB, BG, BR, BW, BY, BZ, CA, CH, CN, CO, CR, CU, CZ, DE, DK, DM, DZ, EC, EE, EG, ES, FI, (21) International Application Number: GB, GD, GE, GH, GM, GT, HN, HR, HU, ID, IL, IN, IS, PCT/EP2007/052098 JP, KE, KG, KM, KN, KP, KR, KZ, LA, LC, LK, LR, LS, (22) International Filing Date: 6 March 2007 (06.03.2007) LT,LU, LY,MA, MD, MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI, NO, NZ, OM, PG, PH, PL, PT, RO, RS, RU, (25) Filing Language: English SC, SD, SE, SG, SK, SL, SM, SV, SY, TJ, TM, TN, TR, (26) Publication Language: English TT, TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, ZW (30) Priority Data: (84) Designated States (unless otherwise indicated, for every 061 10735.5 6 March 2006 (06.03.2006) EP kind of regional protection available): ARIPO (BW, GH, (71) Applicant (for all designated States except US): GM, KE, LS, MW, MZ, NA, SD, SL, SZ, TZ, UG, ZM, AKZO NOBEL COATINGS INTERNATIONAL ZW), Eurasian (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), B.V. [NL/NL] ; Velperweg 76, NL-6824 BM Arnhem (NL). European (AT,BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GB, GR, HU, IE, IS, IT, LT,LU, LV,MC, MT, NL, PL, (72) Inventors; and PT, RO, SE, SI, SK, TR), OAPI (BF, BJ, CF, CG, CI, CM, (75) Inventors/Applicants (for US only): BURSTING, GA, GN, GQ, GW, ML, MR, NE, SN, TD, TG). Wolfgang Ludwig [DE/DE]; Alter Sportplatz 37, D-48727 Billerbeck (DE). SCHROEDER, Philipp Published: [DE/DE]; Karl-Wagenfeld-Strasse 4, D-48727 Biller — without international search report and to be republished beck (DE). KNOEBEL, Markus Oliver [DE/DE]; upon receipt of that report Eleonore-Pollmeyer-Strasse 70, D-48653 Coesfeld (DE). (74) Agent: SCHALKWIJK, Pieter Cornells; Akzo Nobel For two-letter codes and other abbreviations, refer to the "G uid N.V , Intellectual Property Department (AIP), P.O. Box ance Notes on Codes and Abbreviations" appearing at the beg in 9300, NL-6800 SB Arnhem (NL). ning of each regular issue of the PCT Gazette. (54) Title: METHOD OF APPLYING A TOP LAYER OF A FLOOR (57) Abstract: Method of applying a top layer of a floor using a levelling compound comprising an inorganic binder, a flow agent, and a colourant wherein the levelling compound is mixed with water to form a slurry which is subsequently applied to form a levelled layer characterized in that a binder with a calcium sulfate content of at least 90 % by weight is used and in that a transparent top coat is applied on the levelled layer using a coating composition comprising an organic binder. METHOD OF APPLYING A TOP LAYER OF A FLOOR The present invention relates to a method of applying a top layer of a floor using a levelling compound comprising an inorganic binder, a flow agent, and a colourant wherein the levelling compound is mixed with water to form a slurry which is subsequently applied to form a levelled layer. Levelling compounds are free-flowing compounds based on inorganic binders, such as calcium sulfate or cement. Commercially available in powder form, these products are mixed with water to form a slurry which is usually poured or pumped onto a floor, where it levels out and hardens to form a smooth levelled floor surface. EP 0 884 291 A 1 discloses the use of a pigmented levelling compound to form a top layer of a floor which does not need to be covered further. To obtain sufficient mechanical strength and wear resistance, such pigmented levelling compounds are based on cementitious binder systems. Such cementitious systems have a relatively high shrinkage and are susceptible to crack formation. Levelling compounds based on calcium sulfate, e.g. as disclosed in DE 101 59 337 A , can be used to form lightweight constructions. However, these calcium sulfate based levelling compounds are typically used for layers supporting floor coverings, such as textile carpeting, PVC carpeting, linoleum or parquet. WO 96/24561 discloses fly ash based compounds which may optionally comprise hydratable gypsum. The use of a pigment is also mentioned. The mixtures are used to make floor underlayments, which serve to carry further floor coverings. The fly ash is used to improve quick setting and high early compressive strength, which is required for use as a floor underlayment, since further layers must be applied on it. The gypsum content of the binder system is below 90 % . WO 03/082766 discloses flooring compounds based on beta calcined calcium sulfate, optionally comprising colourants. The compounds are used for subfloors and floor underlayments. It is the object of the invention to provide a method for applying a top layer of a floor without shrink effects or crack formation and with good mechanical properties, allowing direct use as a top floor layer without additional floor covering. The object of the invention is achieved by a method of applying a top layer of a floor using a levelling compound comprising an inorganic binder, a flow agent, and a colourant, wherein the levelling compound is mixed with water to form a slurry which is subsequently applied to form a levelled layer, characterized in that a binder with a calcium sulfate content of at least 90 % by weight is used and in that a transparent top coat is applied on the levelled layer using a coating composition comprising an organic binder. Contrary to expectation, it was found that pigments still allow the formulation of compounds with a high calcium sulfate content and a sufficient self-levelling flow. The floors obtained with the levelling compounds according to the invention can be homogeneously coloured and can be used directly without further floor covering. The top floor is finished by applying a transparent top coat comprising an organic binder on the cured layer of the levelling compound. Such a transparent top coat can for example be made using a transparent oil finishing, a transparent wax finishing, a reaction resin based transparent finishing, e.g. epoxy resin or polyurethane resin, transparent alkyd lacquers, or a dispersion based film-forming finishing. Suitable polyurethane resins are for example aqueous dispersions of polyurethanes, for instance based on a carbonyl - hydrazine crosslinking system, such as Neopac® E125 available from DSM Neoresins. Water or solvent borne oxidatively drying fatty acid modified polyurethanes can also be used. Suitable oil finishings can for example be based on linseed oil or tung oil. A suitable transparent top coat can for example be prepared by using HP-oil in combination with HP Hartwachs, both of IRSA, Germany. A commercially available suitable epxoxy system is EP 700 E of KLB Kδtztal. Suitable examples of aqueous two component polyurethane systems are Coelan® 2K PU and Altramex® 7600 Polytec. The amount of water to be mixed with the dry levelling compound generally is in the order of 10 - 40 wt.%, e.g., between 20 and 32 wt.%. These amounts of water are not sufficient to reduce the viscosity sufficiently to obtain a self- levelling compound. Therefore, flow agents are used. Generally, these flow agents are polymeric resins used in concentrations of up to about 5 wt.%, e.g., about 0.05 - about 2 wt.% of the dry composition of the levelling compound. Suitable examples of flow agents are melamine formaline sulfonates, lignine sulfonates, beta naphthalene sulfonic acid aldehyde condensation products, polyalkylallyl sulfonates, casein, polycarboxylates, acrylic copolymers, alkylnaphthalene sulfonates, and alkylnaphthalene sulfonic acid formaline condensation product salts. In order to prevent bleeding of water and aggregate separation, one or more thickeners can be used. Suitable examples of thickeners are cellulose ethers such as methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, ethylhydroxy- methyl cellulose, ethylhydroxyethyl cellulose, and carboxymethyl cellulose, polyacrylamide polyethylene oxide, polyvinyl alcohol, casein, starch ether, sulfonic organic polymers, xanthan gum, guar gum or polysaccharide. The amount of thickener generally is below 5 wt.%, e.g., between 0.01 and 1.0 wt.% of the dry composition. Addtionally, use can be made of one or more defoamers, which can for instance be based on a polyol, a glycol, a fatty acid ester, silicones, siloxanes, ethylene oxide or propylene oxide, alkoxy polymers or mineral oils. The amount of defoamer generally is below 1 wt.%, e.g. between 0.05 - 0.8 wt.% of the dry composition. The used colourant can be a dye or an organic or inorganic pigment or mixtures of organic and/or inorganic pigments and/or dyes. Effect pigments, such as metallic or pearlescent pigments or colour shift pigments, can also be used. The pigments can for example be in the powder or granular form or in the liquid or paste form. The pigment content in the levelling compound is within the following range: 0.01 - 10 wt.% of the dry levelling compound, preferably 0.1 - 2 wt.% of the dry levelling compound. Suitable organic colour pigments are for example monoazo pigments: C.I Pigment Brown 25; C.I. Pigment Orange 5 , 13, 36, 38, 64, and 67; C.I. Pigment Red 1, 2 , 3 , 4 , 5 , 8 , 9 , 12, 17, 22, 23, 3 1, 48:1 , 48:2, 48:3, 48:4, 49, 49:1 , 5 1 :1 , 52:1 , 52:2, 53, 53:1 , 53:3, 57:1 , 58:2, 58:4, 63, 112, 146, 148, 170, 175, 184, 185, 187, 191 :1 , 208, 210, 245, 247, and 251 ; C.I.