Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Specific organic component
Reexamination Certificate
2000-09-11
2004-06-01
Mruk, Brian P. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Specific organic component
C510S220000, C510S221000, C510S222000, C510S228000, C510S232000, C510S507000, C510S511000, C510S532000, C423S332000, C423S327100, C423S328200
Reexamination Certificate
active
06743766
ABSTRACT:
CROSS-REFERENCES TO RELATED APPLICATIONS
The present invention is described in the German priority application No. 19943551.0, filed Sep. 11, 1999, which is hereby incorporated by reference as is fully disclosed herein.
BACKGROUND OF THE INVENTION
The invention relates to a sparingly soluble alkali metal silicate, to a process for its preparation and to its use in detergents and cleaners.
Crystalline sheet sodium silicates (phyllosilicates) of the formula NaMSi
x
O
2x+1
.yH
2
O, where M is sodium or hydrogen, x is a number from 1.9 to 4 and y is a number from 0 to 20, and preferred values for x are 2, 3 or 4, have proven to be suitable replacements for the detergent builders phosphate and zeolite. The use of such crystalline phyllosilicates for softening water is described, for example, in EP-A-0 164 514.
Detergent builders fulfill a large number of functions. Of these, particular mention may be made of the removal of or reduction in water hardness in the mains water used for washing and the supply of alkalinity, i.e. the regulation of and increase in the pH in the wash liquor.
The removal of the water hardness present in mains water in the form of calcium and magnesium ions is important since, at the customary, in particular relatively high, washing temperatures, it causes inorganic incrustations on heating elements and walls of the washing machine and also on textiles, and causes the anionic surfactants frequently used to precipitate out in the form of so-called lime soaps. This results in a reduction in detergency and leads to a gray haze on the laundry after just a few wash cycles.
The abovementioned inorganic incrustations consist of water hardness precipitated out in the form of calcium carbonate or of deposited residues of dissolved detergent builder components. The desired increase in the pH in the wash liquor results in the soil particles which may be present having a higher surface charge, making them easier to remove from the fabric being washed.
Silicatic detergent builders are divided into readily soluble types and sparingly soluble types. Readily soluble silicatic detergent builders are frequently pure X-ray-amorphous sodium silicates. Although these sodium silicates, which are prepared from spray-dried sodium water glass, are able to contribute to the regulation of the pH, they are only able to make a small contribution to the lowering of the water hardness.
Sparingly soluble detergent builders, which primarily include the aluminum-containing silicates (zeolites), are, however, not able by themselves to favorably influence the pH in the wash solution, i.e. to provide higher alkalinity of the wash solution.
The same is true for the sparingly soluble magnesium-containing silicates, as are known, for example, from EP-A-0 550 048.
SUMMARY OF THE INVENTION
There has therefore hitherto been a lack of builders of the sparingly soluble type which, despite their poor solubility, have a high water-softening capacity and at the same time display convincing effectiveness as builders. The object of the present invention was therefore to provide a sparingly soluble builder based on alkali metal silicate which has both a high water-softening capacity and is itself highly effective as a builder.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
This object is achieved by a sparingly soluble alkali metal silicate of the type mentioned in the introduction, which comprises alkali metal phyllosilicates in finely divided form in a non-phyllosilicatic alkali metal silicate environment of the formula x M
I
2
O.y SiO
2
, in which M
I
is an alkali metal and y/x is (1.9 to 500): 1. An essential feature here is that the alkali metal phyllosilicates are embedded into a non-phyllosilicatic matrix.
The crystalline alkali metal silicate preferably corresponds overall to the formula
a
M
I
2
O.
b
M
II
O.
c
X
2
O
3
.d
Z
2
O
5
.e
SiO
2
.f H
2
O
in which M
I
is an alkali metal, M
II
is an alkaline earth metal, X is an element of the third main group and Z is an element of the fifth main group of the Periodic Table of the Elements and the following also applies:
0≦a≦1;
0≦c/e≦0.05;
0≦die≦0.25;
1.9≦e≦4;
0≦f≦20.
Preferably,
0 ≦a≦1;
0≦b≦0.05;
0≦c/e≦0.025;
0≦d/e≦0.01;
1.9≦e≦4;
0≦f≦20.
Particularly preferably,
0≦a≦1;
b=0;
c/e=0;
d/e=0;
19≦e≦4;
0≦f≦20.
Preferably, y/x is (2.0 to 200): 1.
M
I
is preferably sodium.
The non-phyllosilicatic alkali metal silicate environment is preferably composed of non-phyllosilicatic sodium silicate.
Such non-phyllosilicatic sodium silicates include, in particular, the amorphous sodium silicates which, in the X-ray powder diffractogram, typically exhibit no sharp reflections which can be assigned to an ordered crystalline structure; they do not have a defined stoichiometric composition either. The alkali metal phyllosilicate is preferably composed of sheet crystalline disodium disilicates.
The latter in turn usually consist of at least one polymorphous phase.
The sparingly soluble alkali metal silicate preferably consists of
1 to 40% by weight of alpha-disodium disilicate,
0 to 60% by weight of beta-disodium disilicate,
10 to 77% by weight of delta-disodium disilicate and
0,1 to 40% by weight, preferably 1 to 20% by weight, of non-phyllosilicatic sodium silicates.
In another embodiment of the invention, the sparingly soluble alkali metal silicate consists of
0 to 40% by weight of alpha-disodium disilicate,
15 to 98% by weight of beta-disodium disilicate,
0 to 40% by weight of delta-disodium disilicate and
0,1 to 50% by weight, preferably 1 to 35% by weight, of non-phyllosilicatic sodium silicates.
In a further embodiment of the invention, the sparingly soluble alkali metal silicate consists of
16 to 98% by weight of alpha-disodium disilicate,
0 to 40% by weight of beta-disodium disilicate,
0 to 50% by weight of delta-disodium disilicate and
0,1 to 50% by weight, preferably 1 to 35% by weight, of non-phyllosilicatic sodium silicates.
In a further embodiment of the invention, the sparingly soluble alkali metal silicate consists of
21 to 98% by weight of alpha-disodium disilicate,
0 to 40% by weight of beta-disodium disilicate,
0 to 50% by weight of delta-disodium disilicate and
0,1 to 50% by weight, preferably 1 to 35% by weight, of non-phyllosilicatic sodium silicates.
In a further embodiment of the invention, the sparingly soluble alkali metal silicate consists of
1 to 40% by weight of alpha-disodium disilicate,
0 to 50% by weight of beta-disodium disilicate,
10 to 98% by weight of delta-disodium disilicate and
0,1 to 50% by weight, preferably 1 to 35% by weight, of non-phyllosilicatic sodium silicates.
In a further embodiment of the invention, the sparingly soluble alkali metal silicate consists of
0 to 4% by weight of alpha-disodium disilicate,
0 to 4% by weight of beta-disodium disilicate,
96 to 100% by weight, preferably 96 to 99% by weight, of delta-disodium isilicate and
0,1 to 4% by weight, preferably 1 to 4% by weight, of non-phyllosilicatic sodium silicates.
In a further embodiment of the invention, the sparingly soluble alkali metal silicate consists of
0 to 10% by weight of alpha-disodium disilicate,
0 to 10% by weight of beta-disodium disilicate,
91 to 100% by weight, preferably 91 to 99% by weight, of delta-disodium disilicate and
0,1 to 10% by weight, preferably 1 to 9% by weight, of non-phyllosilicatic sodium silicates.
The sparingly soluble alkali metal silicate preferably comprises up to 10% by weight, based on the alkali metal silicate content, of further constituents.
The further constituents are preferably cationic and/or anionic constituents.
The cationic constituents are preferably alkali metal ions and/or alkaline earth metal cations and/or Fe, W, Mo, Ta, Pb, Sn, Al, Zn, Ti, V, Cr, Mn, Co and/or Ni.
The anionic constituents are preferably sulfates, fluorides, chlorides, bromides, iodides, carbonates, hydrogencarbonates, nitrates, oxide hydrates, phosphates and/or borates.
The sparingly soluble alkali metal silicate preferably comprises up
Bauer Harald
Holz Josef
Schimmel Guenther
Tapper Alexander
Clariant GmbH
Mruk Brian P.
Silverman Richard P.
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