Non-efflorescing cementitious mortar compositions

1. A non-efflorescing cementitious mortar composition, free of reactive silica material, in the form of a dry-mortar composition or an aqueous mortar composition, comprising

a) from 1% by weight to 10% by weight of ordinary portland cement, based on the dry weight of the cementitious mortar composition

b) from 1% by weight to 30% by weight of calcium aluminate cement, based on the dry weight of the cementitious mortar composition

c) from 1% by weight to 15% by weight of calcium sulfate, based on the dry weight of the cementitious mortar composition and

d) from 0.5% by weight to 30% by weight, based on the dry weight of the cementitious mortar composition, of an aqueous polymer dispersion or a water-redispersible polymer powder of polymers based on one or more monomers from the group consisting of vinyl esters, (meth)acrylates, vinyl aromatics, olefins, 1,3-dienes and vinyl halides and, if required, further monomers copolymerizable therewith, the weight percentage of aqueous polymer dispersion based on the weight of solids in the dispersion, wherein reactive silica material means non-crystalline silica which is in metastable form and can react with cement hydration product calcium hydroxide to form hydrated calcium silicate, and wherein in the cementitious mortar composition, the components a), b), c) and d) are present in a weight ratio of a):b):c):d) of 1 to 1.5:2 to 4:1 to 1.5:2 to 4.

2. The cementitious mortar composition of claim 1 , comprising as calcium sulfate c), anhydrite, hemi-hydrate, and/or gypsum.

3. The cementitious mortar composition of claim 1 , comprising one or more polymers selected from the group consisting of vinyl acetate homopolymers; copolymers of vinyl acetate with ethylene; copolymers of vinyl acetate with ethylene and with one or more other vinyl esters; copolymers of vinyl acetate with ethylene and (meth)acrylic ester; copolymers of vinyl acetate with (meth)acrylates and other vinyl esters; copolymers of vinyl acetate with ethylene and vinyl chloride; copolymers of vinyl acetate with acrylates; styrene-acrylic ester copolymers; and styrene-1,3 butadiene copolymers.

4. The cementitious mortar composition of claim 1 , comprising one or more further ingredients selected from the group of fillers, pigments, thickeners, retardants, antifungal agents, wetting agents and dispersing agents.

5. A process for the preparation of a cementitious mortar composition as claimed in claim 1 , comprising mixing components a) to d), and optionally one or more of the abovementioned further ingredients, to form a dry mortar in a powder mixer, and homogenizing the mixture.

6. A process for the preparation of a cementitious mortar composition as claimed in claim 1 , comprising mixing the aqueous polymer dispersion d) with the components a) to c), and optionally further ingredients, and if necessary an additional amount of water to obtain a pasty mortar.

7. A building adhesive, plaster, render, knifing filler, flooring screed, leveling compound, sealing slurry, jointing mortar and coating, comprising a cementitious mortar composition of claim 1 .

8. A powder paint, comprising a cementitious mortar composition of claim 1 .

9. A thin layer coating having a thickness of 0.1 to 3 mm, comprising a cementitious mortar composition of claim 1 .

10. The composition of claim 1 , wherein the portland cement contains Fe 2 O 3 in an amount of less than 2.5% by weight based on the weight of portland cement.

11. The composition of claim 1 , wherein the calcium aluminate cement contains Fe 2 O 3 in an amount of less than 3 weight percent based on the weight of the calcium aluminate cement.

12. The composition of claim 10 , wherein the calcium aluminate cement contains Fe 2 O 3 in an amount of less than 3 weight percent based on the weight of the calcium aluminate cement.

13. A non-efflorescing cementitious mortar composition, free of reactive silica material, in the form of a dry-mortar composition or an aqueous mortar composition, comprising

a) from 1% by weight to 10% by weight of ordinary portland cement, based on the dry weight of the cementitious mortar composition

b) from 1% by weight to 30% by weight of calcium aluminate cement, based on the dry weight of the cementitious mortar composition

c) from 1% by weight to 15% by weight of calcium sulfate, based on the dry weight of the cementitious mortar composition and

d) from 0.5% by weight to 30% by weight, based on the dry weight of the cementitious mortar composition, of an aqueous polymer dispersion or a water-redispersible polymer powder of polymers based on one or more monomers from the group consisting of vinyl esters, (meth)acrylates, vinyl aromatics, olefins, 1,3-dienes and vinyl halides and, if required, further monomers copolymerizable therewith, the weight percentage of aqueous polymer dispersion based on the weight of solids in the dispersion, wherein reactive silica material means non-crystalline silica which is in metastable form and can react with cement hydration product calcium hydroxide to form hydrated calcium silicate, and wherein in the cementitious mortar composition, the components a), b), c) and d) are present in a weight ratio of a):b):c):d) of 1 to 1.5:2 to 4:1 to 1.5:2 to 4,

and comprising as calcium sulfate c), anhydrite, hemi-hydrate, or gypsum.

14. The cementitious mortar composition of claim 2 , comprising one or more polymers selected from the group consisting of vinyl acetate homopolymers; copolymers of vinyl acetate with ethylene; copolymers of vinyl acetate with ethylene and with one or more other vinyl esters; copolymers of vinyl acetate with ethylene and (meth)acrylic ester; copolymers of vinyl acetate with (meth)acrylates and other vinyl esters; copolymers of vinyl acetate with ethylene and vinyl chloride; copolymers of vinyl acetate with acrylates; styrene-acrylic ester copolymers; and styrene-1,3 butadiene copolymers.

15. The cementitious mortar composition of claim 3 , comprising one or more further ingredients selected from the group of fillers, pigments, thickeners, retardants, antifungal agents, wetting agents and dispersing agents.

16. A building adhesive, plaster, render, knifing filler, flooring screed, leveling compound, sealing slurry, jointing mortar and coating, comprising a cementitious mortar composition of claim 7 .

17. A powder paint, comprising a cementitious mortar composition of claim 8 .

18. A thin layer coating having a thickness of 0.1 to 3 mm, comprising a cementitious mortar composition of claim 9 .

19. The composition of claim 10 , wherein the portland cement contains Fe 2 O 3 in an amount of less than 2.5% by weight based on the weight of portland cement.

20. The composition of claim 11 , wherein the calcium aluminate cement contains Fe 2 O 3 in an amount of less than 3 weight percent based on the weight of the calcium aluminate cement.