Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Solid – shaped macroscopic article or structure
Reexamination Certificate
2000-07-05
2003-03-04
Kopec, Mark (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Solid, shaped macroscopic article or structure
C510S337000, C510S349000, C510S352000, C510S359000, C510S443000, C510S444000, C510S456000, C510S459000, C510S467000, C510S495000, C510S510000, C510S533000, C510S534000
Reexamination Certificate
active
06528474
ABSTRACT:
This invention relates to a process for the production of detergents which contain a soluble builder system and which are substantially free from alumosilicates.
Builders are now among the most important classes of substances for building detergents and cleaners. The principal requirements builders are expected to satisfy include, above all, the softening of water, the boosting of the detergent effect, the inhibition of redeposition and the suspension of soil. Builders are intended to contribute towards the alkalinity required for the washing process, to have a high absorption capacity for surfactants, to improve the effectiveness of the surfactants, to make positive contributions to the properties of the solid products, for example in powder form, and thus to have a structure-forming effect or even to ease the dust problem. These various requirements cannot normally be satisfied by only one builder component alone, so that a system of builders and cobuilders is generally used.
Alumosilicates, particularly the water-insoluble sodium alumosilicate zeolite NaA, are widely used in detergents. Although these zeolites do require the use of cobuilders, such as polymeric polycarboxylates, above all to prevent incrustations, they are eminently suitable as carriers for surfactants.
Numerous processes which utilize the carrier function of alumosilicates for incorporating surfactants in powder-from detergents are known from the prior art. These compositions can be produced by spray drying processes, which start out from zeolite and surfactant-containing slurries, and by granulation processes in which solids, especially zeolites, are treated with liquid or paste-like surfactant preparations. If zeolite-reduced or even zeolite-free detergents are to be produced, the problem arises that the physical properties of the compositions, such as their storage stability and flowability, deteriorate with decreasing zeolite content. The products tend to become sticky on account of the surfactant content.
DE-A-44 42 977 is concerned with zeolite-reduced detergents. The extruded detergents produced in accordance with this document, which have bulk densities above 600 g/l, contain anionic and optionally nonionic surfactants and water-soluble builders, such as sodium carbonate and amorphous sodium silicate, in such quantities that zeolite can be completely or partly replaced without any process-related problems in the production of these detergents by extrusion. To achieve this, the zeolite content (based on water-free active substance) is limited to an average of less than 19% by weight and the combined sodium carbonate and amorphous sodium silicate content (based on water-free active substance) is adjusted to a value of 10 to 40% by weight, the ratio by weight of sodium carbonate to sodium silicate being from 5:1 to 1:10 and the sodium carbonate used being at least partly granular.
According to International patent application WO 98/54289, free-flowing powders with a high surfactant and low builder content, more especially a low zeolite content, are obtained by at least partly replacing the basic granules by separate granules which contain individual ingredients in highly concentrated form. Preferred detergents are made up of anionic surfactant granules containing at least 60% by weight of anionic surfactant, nonionic surfactant granules containing at least 20% by weight of nonionic surfactant and builder granules containing at most 10% by weight of surfactant.
Earlier German patent application 198 58 887.9 describes a process for the production of a detergent compactate with a bulk density above 700 g/l in which an aqueous preparation of an amorphous sodium silicate with an Na
2
O:SiO
2
ratio (modulus) of 1:2 to 1:3.3 and a polymeric polycarboxylate (M=500 to 10,000 g/mol) is sprayed together with other detergent ingredients in a dryer and optionally granulated at the same time. The resulting basic detergent is compacted after the optional addition of other ingredients. The silicatelpolymer slurry is preferably spray-dried and compacting is carried out by extrusion. The detergents thus produced are zeolite-reduced or totally zeolite-free and, instead, contain an amorphous silicate in quantities of 15 to more than 20% by weight and small quantities of soda as their principal builder.
A process in which a detergent containing a soluble builder system with alkali metal carbonate as the main builder is obtained in the form of free-flowing storage-stable granules has never been described in the literature. Earlier German patent application 1999 12 679.8 describes a phosphate- and alumosilicate-free detergent. Besides the main builder, alkali metal carbonate, the detergent contains silicates, phosphonates, polymeric polycarboxylates with a molecular weight of <10,000 g/mol and optionally an acidic component in the soluble builder system. The advantages of this soluble builder system include its excellent solubility, its better residue behavior compared with zeolite-containing detergents and improved inhibition of soil redeposition. In addition, this builder system can be used in small doses in relation to the surfactant content of the detergent and is thus particularly suitable for high-surfactant detergents.
High-surfactant, builder-reduced detergents are particularly susceptible to production problems, the builders used additionally having even poorer carrier properties than the traditional zeolites. If the processes recommended in the prior art for zeolite-containing detergents are used to produce such a detergent, the products flow poorly, form lumps in storage and, accordingly, are difficult to dispense into the washing machine.
A process for the production of substantially alumosilicate-free detergents containing a soluble builder system which provides free-flowing and storage-stable granules has now been found.
In a first embodiment, therefore, the present invention relates to a process for the production of a particulate, substantially alumosilicate-free detergent in which an anionic surfactant acid is sprayed onto a detergent component which contains anionic surfactant and builders in order to increase the anionic surfactant content.
Processes in which anionic surfactant acids are added in at least two different process steps are particularly preferred. In one particularly advantageous embodiment, the anionic surfactant acid is sprayed onto the detergent component containing anionic surfactant and builders in a mixer. In this case, spraying on of the anionic surfactant acid is preferably accompanied by granulation.
In another preferred embodiment, the detergent component containing anionic surfactant and builders consists of spray-dried basic granules.
In a preferred variant of this embodiment, a) a slurry containing detergent components suitable for spray drying is sprayed in a drying tower and dried to a water content of at most 20% by weight, b) the spray-dried basic granules are mixed with an alkali metal salt, c) an anionic surfactant acid is sprayed onto the mixture and d) other granules are optionally added to and mixed with the compound.
Acidic precursors, such as anionic surfactant acids, phosphonic acids and optionally acidic or partially neutralized polymers treated with a neutralizing agent are preferably used in the slurry. Preferred neutralizing agents are alkali metal hydroxides, more especially sodium hydroxide, or alkali metal carbonate, more especially sodium carbonate. In addition to these neutralized ingredients, the slurry normally already contains the alkali metal silicate, parts of the alkali metal carbonate and optionally sodium sulfate. The water content of the slurries used for spray drying is normally in the range from 20 to 50%. Preparation of the slurry and spray drying may be carried out as described in European patent application EP-A-0 273 688. In another preferred embodiment, however, the heat of neutralization released during the neutralization of the acidic precursors may be directly used to heat the slurries.
The anionic surfactants which may be used
Artiga Gonzalez Rene-Andres
Lietzmann Andreas
Liphard Maria
Roehl Wilfried
Harper Stephen D.
Henkel Kommanditgesellschaft auf Aktien
Kopec Mark
Mruk Brian P.
Murphy Glenn E. J.
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