COMPOSITION FOR A POWDER MORTAR AND A POWDER MORTAR, IN PARTICULAR FOR USE AS A SPACKLING COMPOUND

Abstract

The invention relates to a composition for a powder mortar comprising one or more fillers, one or more binders, one or more thickeners and optionally further additives, wherein at least one of the one or more binders comprises a starch, and wherein at least one of the one or more thickeners is an etherified starch. The invention further relates to a corresponding powder mortar, in particular for use as a spackling compound.

Claims

1. A composition, comprising one or more fillers, one or more binders, one or more thickeners and optionally further additives, wherein at least one of the one or more binders is a starch, and wherein at least one of the one or more thickeners is an etherified starch.

2. The composition according to claim 1, wherein the starch is selected from the group consisting of potato starch, wheat starch, rice starch, corn starch, tapioca starch, pea starch and any combinations thereof.

3. The composition according to claim 1, wherein the starch is selected from the group consisting of native starch, pregelatinized starch, extruded starch, spray-cooked starch, spray-dried starch, drum-dried starch, cold-water-soluble starch, cold-water-swellable starch, annealed starch, oxidized starch, crosslinked starch, esterified starch and non-modified native starch.

4. The composition according to claim 1, wherein the starch is present in an amount of from more than 0.5% by weight to less than 7% by weight of the total composition.

5. The composition according to claim 1, wherein the starch is a native, pregelatinized starch, an oxidized starch or a pregelatinized starch, a native, pregelatinized wheat starch, a native, pregelatinized, cold-water-swellable starch, an oxidized, cold-water-swellable wheat starch, or a pregelatinized, cold-water-swellable wheat starch.

6. The composition according to claim 1, wherein the starch comprises one or more polysaccharides having an average molecular weight M.sub.w of between 15,000 g/mol and 200,000,000 g/mol.

7. The composition according to claim 1, wherein the one or more fillers are selected from the group consisting of calcium carbonates, calcium magnesium carbonates, calcium sulfates, perlite, expanded perlite, magnesium carbonate, glass, mica and resin microbeads, or any combination thereof.

8. The composition according to an claim 1, wherein the etherified starch is etherified with sodium-monochloroacetate or alkylene oxides with the general formula C.sub.nH.sub.2nO, where n=2 to 5.

9. The composition according to an claim 1, wherein the etherified starch is selected from the group consisting of potato etherified starch, wheat etherified starch, rice etherified starch, corn etherified starch, tapioca etherified starch, pea etherified starch or any combinations thereof, preferably a wheat etherified starch and/or a potato etherified starch and combinations thereof.

10. The composition according to claim 1, wherein the etherified starch is a pregelatinized etherified starch.

11. The composition according to claim 1, wherein the etherified starch is present in the composition in an amount of from more than 0.01% by weight to less than 5% by weight of the total composition.

12. The composition according to claim 1, wherein the composition comprises at least two thickeners, wherein the at least two thickeners are an etherified starch and a further thickener selected from the group consisting of cellulosic ether, cellulose-based gum, methyl cellulose, hydroxyethyl cellulose, hydroxyethylmethyl cellulose, dextran, carboxymethyl dextran, dextran-sulfonate salt, chitosan, xanthan gum, carboxymethyl cellulose or a salt thereof, carrageenan, hydroxyethyl hydroxypropyl cellulose, ethyl hydroxyethyl cellulose, hydroxypropylmethyl cellulose, methylhydroxylpropyl cellulose, polyacrylamide, polyacrylamide copolymer, ethylene maleic anhydride copolymer, crosslinked carboxymethylcellulose, polyvinyl alcohol copolymers or crosslinked polyethylene oxide and esterified starch.

13. The composition according to claim 1, wherein the composition comprises at least three thickeners, wherein the at least three thickeners are an etherified starch and two further thickeners selected from the group consisting of cellulosic ether, cellulose-based gum, methyl cellulose, hydroxyethyl cellulose, hydroxyethylmethyl cellulose, dextran, carboxymethyl dextran, dextran-sulfonate salt, chitosan, xanthan gum, carboxymethyl cellulose or a salt thereof, carrageenan, hydroxyethyl hydroxypropyl cellulose, ethyl hydroxyethyl cellulose, hydroxypropylmethyl cellulose, methylhydroxylpropyl cellulose, polyacrylamide, polyacrylamide copolymer, ethylene maleic anhydride copolymer, crosslinked carboxymethylcellulose, polyvinyl alcohol copolymers, crosslinked polyethylene oxide and esterified starch.

14. The composition according to claim 1, wherein the composition comprises at least two binders, wherein the at least two binders are a starch and a further binder, wherein the further binder is a mineral binder or an organic binder.

15. The composition according to claim 1, wherein the composition comprises at least two binders, wherein the at least two binders are a starch and a further organic binder selected from the group consisting of a further starch, polyvinyl acetate, polyethylene vinyl acetate, polyacrylate and polyvinyl alcohol, preferably polyvinyl acetate and polyethylene vinyl acetate.

16. The composition according to claim 1, wherein the composition consists of a filler, a starch, an etherified starch and a cellulosic ether and optionally a dispersion powder and/or polyacrylamide.

17. Powder mortar comprising the composition according to claim 1.

18. A method of using a starch in combination with starch ether comprising the step of adding the starch and the starch ether in a powder mortar.

19. The composition according to claim 1, wherein the etherified starch is selected from the group consisting of pregelatinized etherified starch, extruded etherified starch, spray-cooked etherified starch, spray-dried etherified starch, drum-dried etherified starch, cold-water-soluble etherified starch, cold-water-swellable etherified starch, annealed etherified starch, oxidized etherified starch, crosslinked etherified starch, and esterified etherified starch.

20. A spackling compound comprising the composition according to claim 1 and water.

Description

EXAMPLES

[0054] Examples are prepared showing the effect in properties of the inventing composition. All examples (V) are prepared by mixing water with the composition in a “kitchen aid” mixing machine in a weight ratio of 0.48:1.

[0055] The interspersing is carried out in about 15 seconds, while some soft mixing with a shovel is done. After waiting for 60 seconds, the mixture is mixed for 30 seconds on level 1 of the mixing machine, followed by 5 seconds on level 2 and finally followed by 25 seconds again on level 1. After a relaxing time for the mixture of 180 seconds, another mixing of 30 seconds on level 1 is followed.

[0056] The different mixtures are shown in table 1. Examples V0, V0-1, V0-2, V1 and V2 are comparison examples. V0 only comprises dispersion powder, but no starch or etherified starch. V0-1 and V0-2 comprise only comprise dispersion powder and etherified starch but no starch. V1 and V2 comprise starch but no etherified starch. Examples V1-1, V1-2 V2-1 and V2-2 are inventive since they comprise starch and etherified starch.

TABLE-US-00001 TABLE 1 Thickener Thickener Thickener Ex- Filler: 1: 2: 3: ample Microdol Solvitose Bermocoll E Agocel S No. A 250 Binder ZPF 431 X 2000 V 0 1000.00 g Vinnapas — 4.00 g 0.22 g 5043N: 25.00 g V 0-1 1000.00 g Vinnapas  0.5 g 4.00 g 0.22 g 5043N: 25.00 g V 0-2 1000.00 g Vinnapas 1.00 g 4.00 g 0.22 g 5043N: 25.00 g V 1 1000.00 g Quellstar — 4.00 g 0.22 g CWS 10: 25.00 g V 1-1 1000.00 g Quellstar  0.5 g 4.00 g 0.22 g CWS 10: 25.00 g V 1-2 1000.00 g Quellstar 1.00 g 4.00 g 0.22 g CWS 10: 25.00 g V 2 1000.00 g Pregeflo — 4.00 g 0.22 g P 100 G: 25.00 g V 2-1 1000.00 g Pregeflo  0.5 g 4.00 g 0.22 g P 100 G: 25.00 g V 2-2 1000.00 g Pregeflo 1.00 g 4.00 g 0.22 g P 100 G: 25.00 g

[0057] Table 2 shows the results.

[0058] Abrasion is tested by bringing up the mixture as prepared with a thickness of about 2 mm on a defined piece of a gypsum board. After drying at room temperature until constant weight (usually 3 days) the piece is weighed and put into an abrasion machine (Taber-Abraser Modell 503) and is rotated 100 times with 60 rotations per minute and sandpaper S 33 and 500 g of check weight. After that, the weight of the piece is checked again and the difference is the abrasion.

[0059] Adhesion is tested by bringing up the mixture as prepared with a thickness of about 2 mm on a gypsum board. Afterwards two tapes (paper or “Kurt”) are placed in the mixture in that way that about 5 cm of the tape are over the edge of the gypsum board. Then it is overdrawn twice with a putty knife. After drying for about 48 hours at room climate the tape is connected to a bucket that is slowly filled with water until the tape cracks off. Then the bucket with the water is weighed. Since there are two tapes the average is calculated.

[0060] Adhesive tensile strength is the stress in N/mm.sup.2 required to rip off a test surface (test disc) glued to a defined surface (substrate) by tensile stress perpendicular to it. As substrate a gypsum plasterboard is used. Two rails with a thickness of 1.5 mm are to be arranged at a distance of about 20 cm on the plasterboard and are attached with an adhesive tape. The mixture is filled in evenly, without air bubbles and excess material is leveled on the rails with a spatula or putty knife. After complete drying (about 48 hours of room climate) a test disc is full-faced glued to the dried mixture with two-component adhesive, followed by inserting a screw into the test disc. Then a wooden plate with a cavity in the form of the test disc is put onto the substrate in that way that the test disc lies in the cavity. After that, the measuring device (Sattec) is put on the wooden plate and a perpendicular connection with the screw is established. Then the crank of the measuring device is turned until the crack occurs. While turning the crank, the force has to rise constantly about 50 +/−5 N/s. The adhesive tensile strength is then calculated by dividing the measured force with the square of the radius x □ of the test disc (here: 1963 mm.sup.2, since the radius of the disc is 25 mm).

[0061] According to abrasion, it has to be said that a smaller value (in g) is better, since then the composition is harder to destroy. According to the adhesions it has to be said that a higher value is better, since that is significant for a stronger connection of the composition with the respective tape. “Kurt” is a special tape by Knauf. According to the adhesive tensile strength, it has to be said that again a higher value is better, since that is significant for a stronger connection of the mixture to the gypsum board.

TABLE-US-00002 TABLE 2 Adhesion adhesive joint tape Adhesion tensile Example Abrasion .sub.”Kurt“ paper tape strength in No. in g in g in g N/mm.sup.2 V 0 3.56 424 369 0.30 V 0-1 3.46 524 314 0.34 V 0-2 3.30 510 308 0.34 V 1 3.74 474 236 0.29 V 1-1 3.14 545 362 0.33 V 1-2 3.09 563 339 0.35 V 2 2.76 730 1015 0.28 V 2-1 2.52 917 1359 0.39 V 2-2 2.37 867 1332 0.38

[0062] The inventive compositions show at least equal, but mostly enhanced properties compared to the respective comparison examples. Especially surprising are the very small amounts of etherified starch, which are enough to generate rather big effects in combination with starch as binder.