Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Heterogeneous arrangement
Reexamination Certificate
2001-03-28
2002-10-22
Douyon, Lorina M. (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Heterogeneous arrangement
C510S351000, C510S353000, C510S357000, C510S491000, C510S495000, C510S498000, C510S535000, C562S097000
Reexamination Certificate
active
06468957
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a process for the production of detergents. More particularly, the invention relates to a process by which it is possible to produce detergent compositions with or without a reduced number of spray drying steps.
Granular detergent compositions are largely produced by spray drying. In the spray drying process, the ingredients, such as surfactants, builders etc. containing around 35 to 50% by weight of water, are mixed to form an aqueous suspension, known as a slurry, and the resulting mixture is sprayed into a hot gas stream in spray drying towers, resulting in the formation of the detergent particles. Both the installations for this process and the operation of the process are expensive because most of the water in the slurry has to be evaporated in order to obtain particles having residual water contents of around 5 to 10% by weight. In addition, although the granules produced by spray drying generally show excellent solubility, they have low bulk densities which leads to higher packaging volumes and transportation and storage capacities. The flowability of spray-dried granules is also far from optimal in view of their irregular surface structure which also has an effect on their appearance. Spray drying processes have a number of other disadvantages, so that there has been no shortage of attempts to carry out the production of detergents without any spray drying whatever or at least to have low levels of spray-dried products in the end product.
Thus, W. Hermann de Groot, I. Adami, G. F. Moretti in “The Manufacture of Modern Detergent Powders”, Hermann de Groot Academic Publisher, Wassenaar, 1995, pages 102 et seq. describe various mixing and granulation processes for the production of detergents. One feature common to all these processes is that premixed solids are granulated in the presence of the liquid ingredients and optionally dried in a following step.
A broad prior art on the non-tower production of detergents also exists in the patent literature. Many of these processes start out from the acid form of anionic surfactants because, in quantitative terms, this class of surfactants represents the largest percentage of detersive substances and because, in the course of their production, anionic surfactants accumulate in the form of the free acids which have to be neutralized to the corresponding salts.
Thus, European patent application EP-A-0 678 573 (Procter & Gamble) describes a process for the production of flowable surfactant granules having bulk densities above 600 g/l, in which anionic surfactant acids are reacted with an excess of neutralizing agent to form a paste containing at least 40% by weight of surfactant and the resulting paste is mixed with one or more powder(s), of which at least one has to be spray-dried and contains anionic polymer and cationic surfactant, the resulting granules optionally being dried. Although this document reduces the percentage of spray-dried granules in the detergents, it does not avoid spray drying altogether.
European patent application EP-A-0 438 320 (Unilever) discloses a batch process for the production of surfactant granules having bulk densities above 650 g/l. In this process, the anionic surfactant acid is added, optionally with other solids, to a solution of an alkaline inorganic substance in water and the whole is granulated with a liquid binder in a high-speed mixer/granulator. Although neutralization and granulation take place in the same apparatus, they are carried out in separate process steps so that the process can only be operated in batches.
European patent application EP-A-0 402 112 (Procter & Gamble) describes a continuous neutralization/granulation process for the production of FAS and/or ABS granules from the acid, in which the ABS acid is neutralized with at least 62% NaOH and is then granulated in the presence of auxiliaries, for example ethoxylated alcohols or alkyl phenols or a polyethylene glycol with a molecular weight of 4,000 to 50,000 melting at temperatures above 48.9° C.
European patent application EP-A-0 508 543 (Procter & Gamble) discloses a process in which a surfactant acid is neutralized with an excess of alkali to form an at least 40% by weight surfactant paste which is subsequently conditioned and granulated, the granules being directly cooled with dry ice or liquid nitrogen.
Dry neutralization processes, in which sulfonic acids are neutralized and granulated, are disclosed in EP 555 622 (Procter & Gamble). According to the teaching of this document, the anionic surfactant acids are neutralized in a high-speed mixer with an excess of fine-particle neutralizing agent having a mean particle size below 5 &mgr;m.
A similar process, which is also carried out in a high-speed mixer and in which sodium carbonate ground to between 2 and 20 &mgr;m in size is used as the neutralizing agent, is described in WO 98/20104 (Procter & Gamble).
Surfactant mixtures which are subsequently sprayed onto solid absorbents and which provide detergent compositions or complonents therefor are also described in EP 265 203 (Unilever). The liquid surfactant mixtures disclosed in this document contain sodium or potassium salts of alkyl benzenesulfonic acids or alkyl sulfuric acids in quantities of up to 80% by weight, ethoxylated nonionic surfactants in quantities of up to 80% by weight and at most 10% by weight water.
Similar surfactant mixtures are also described in earlier EP 211 493 (Unilever). According to the teaching of this document, the surfactant mixtures to be sprayed on contain between 40 and 92% by weight of a surfactant mixture and more than 8 to at most 60% by weight of water. At least 50% of the surfactant mixture itself consists of polyalkoxylated nonionic surfactants and ionic surfactants.
A process for the production of a liquid surfactant mixture of the three components anionic surfactant, nonionic surfactant and water is described in EP 507 402 (Unilever). The surfactant mixtures disclosed in this document, which are said to contain very little water, are obtained by combining equimolar quantities of neutralizing agent and anionic surfactant acid in the presence of nonionic surfactant.
DE-A-42 32 874 (Henkel KGaA) discloses a process for the production of detersive anionic surfactant granules by neutralizing anionic surfactants in their acid form. However, only solid powders are disclosed as the neutralizing agents. The granules obtained have surfactant contents of around 30% by weight and bulk densities below 550 g/l.
EP-A-642 576 (Henkel KGaA) describes a two-step granulation process carried out in two mixer/granulators arranged in tandem, 40 to 100% by weight, based on the total quantity of constituents used, of the solid and liquid constituents being pregranulated in a first low-speed granulator and the “pregranules” being mixed with the remaining constituents, if any, and converted into granules in a second high-speed granulator.
EP 772 674 (Henkel KGaA) describes a process for the production of surfactant granules by spray drying in which anionic surfactant acid(s) and highly concentrated alkaline solutions are separately exposed to a gaseous medium and mixed in a multicomponent nozzle, neutralized and spray-dried by spraying into a hot gas stream. The fine-particle surfactant particles thus obtained are then agglomerated in a mixer to form granules with bulk densities above 400 g/l.
Now, the problem addressed by the present invention was to provide a process by which it would be possible to produce detergents with or without a reduced number of spray drying steps. The process to be provided by the invention would also enable the acid forms of detergent raw materials to be processed in a direct and economically attractive manner, but would avoid the disadvantage of the energy-intensive evaporation of water as far as possible. Theoretical solutions to the described problems are described in the prior-art literature cited in the foregoing. Nevertheless, the processes in question are attended by a number of disadvantages:
the neutralization with
Larson Bernd
Markiefka Josef
Raehse Wilfried
Schulze Wieland
Sunder Matthias
Douyon Lorina M.
Harper Stephen D.
Henkel Kommanditgesellschaft auf Aktien
Murphy Glenn E. J.
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