DETERGENT COMPOSITION AND DISHWASHING PROCESS
Introduction
The present invention refers to a detergent, preferably for dishwashing, with low contents of active agents (surface active agents or surfactants) and high viscosity, showing also low cloud point.
Dishwashing detergents commercially available, up to the present time, can be divided, basically, into three groups: low quality products, representing 33%, traditional products, representing 65% and distinguishing products, representing 2%.
Consumers may notice the difference between the above described products through the correspondence viscosity, of fat removal; foam durability and performance.
Despite the success of the products now commercially available, there is still a problem, for example, with consumers' skin irritation, among others.
Thus, one of the purposes of the present invention is to provide a detergent, preferably for dishwashing, at low cost, with extremely low concentration of surfactants, showing high viscosity and reducing considerably the problem of the consumers' skin irritation.
The reduction of the consumers' skin irritation is explained by the reduction of the concentration of surfactants, which
are the products traditionally considered to be the cause of this kind or problem.
Therefore, the composition of the present invention shows excellent and unexpected results in its performance, for example, in the dishwashing, due to the new combination of an extremely low concentration of surfactants, totalling up to 7.0% by weight, (sum of all the surfactants), of anionic, nonionic and amphoteric surfactants as well as in inorganic salt electrolytes.
State of the Art
Document WO 95/02664, Jeye Group Pic, discloses a concentrated liquid containing sulphate ether based surfactants and others, besides electrolytes and/or hydrotropes .
Document WO 93/25650, Henkel Corporation, describes a method of preparing highly concentrated surfactant compositions, combined with electrolytes of organic and inorganic salts.
Document EP 392 667, Vista Chemical Co., discloses a composition for use in thixotropic salt and sulphate ether based-detergent formulations. The minimum concentration of sulphate ether in said formulation is of 5% by weight.
Document EP 254, 653, Cotelle S.A., refers to a process of preparing a concentrated detergent in order to obtain a viscous composition upon its corresponding dilution in water, showing a blend of 10 to 70%, by weight, of anionic surfactant, of 2 to 20%, by weight, of nonionic, amphoteric and zwitteronic surfactants.
Background of the Present Invention
As can be easily seen, the state-of-the-art teachings do not reveal detergent compositions with the low surfactant concentration of the present invention's composition, i.e., in present invention the sum of the surfactants (anionic, nonionic, and amphoteric) do not exceed 7%, by weight.
It is also seen that the sulphate ether concentration in the present invention is limited to 3.0%, by weight.
Besides, as can be seen in Table 1 and 2 given below, despite the low concentration of active agents (surfactants), the present invention presents a notably different performance compared with the state-of-the-art compositions of the same character.
Detailed Description of the Present Invention
The present invention refers to a high performance detergent composition, having a low concentration of active agents, as shown below, comprising the following surfactants:
(a) (LES) - M+ - lauryl ether sulphate combined with cations, where M is selected among alkali metal, alkaline-earth metal, ammonium and alike ions.
In the present invention, the preferred lauryl ether sulphate is SLES - sodium lauryl ether sulphate, which is an anionic surfactant, whose carbon chain contains 8
to 10 carbon atoms and presents an ethoxylation number varying from 1 to 3.
The SLES concentration in the present composition ranges from 0,5 to 4.0%, by weight, showing preferably a concentration in the range of 0.8 to 3.0%, by weight .
(b) APG - alkyl polyglucoside, an anionic surfactant, whose carbon chain contains 8 to 16 carbon atoms with an oligomeriszation number in the range of 0.8 to 1.6.
The APG concentration in the present composition ranges from 0.1 to 1.5% by weight, showing preferably a concentration of 0.5%, by weight ,
(c) CAPB - cocoamido-propyl-betaine, an amphoteric surfactant, whose carbon chain, contains from 8 to 16 carbon atoms.
The CAPB concentration in the present composition ranges from 0.1 to 1.5% by weight, showing preferably a concentration of 0.5%, by weight.
(d) LAS-Na - sodium alkyl benzene sulphonate, an anionic surfactant, whose carbon chain contains from 8 to 16 carbon atoms .
The concentration of LAS-Na in the present composition ranges from 0.5% to 3.0%, by weight, showing, preferably, a concentration of 1.78%, by weight .
(e) LAS-TEA - triethanolamine alkyl benzene sulphonate, an anionic surfactant, whose carbon chain contains 8 to 16 carbon atoms.
The concentration of LAS-TEA ranges from 0.5 to 3.5%, by weight, showing preferably a concentration of 2.20%, by weight.
One notes that on effecting the summation of the concentrations of LAS-Na and LAS-TEA one should consider the fact that the molecular weight of said components increases the effective surfactant's concentration.
This means that the total sum of the concentrations of LAS- Na and LAS-TEA in fact must be subtracted by, approximately, 30% due to the existence of Na and TEA.
The formulation of the present invention also includes electrolytes selected from inorganic salts.
The useful inorganic salts in the present invention are selected among salts of alkaline ions and/or alkaline-earth ions and anions selected among halogens and sulphates.
Thus, the preferred salts in the present invention are selected among NaCl, MgCl , MgS04, among others.
The concentrations of inorganic salts in the present invention ranges from 0.5 to 3.0%, by weight and preferably they are present in a concentration of 1.6%, by weight.
Embodiment Examples
The following examples illustrate the embodiment of the present invention. Such examples show some of the preferred embodiments and shall not be limited in their scope.
4 to 10 kg of anionic surfactants, 0.75 to 1.5 kg of nonionic surfactants, 1 to 2 kg of amphoteric surfactants and 92 to 96 kg of water are added to a stirred vessel.
The nonionic surfactant is previously heated to 40°C to be afterwards incorporated in the final blend.
After attaining a complete and homogeneous solution, water is added to the surfactant blend to complete the volume of the reaction vessel, also adding dyes and perfumes.
The blend is stirred during some more minutes.
The final product must have a clear and transparent appearance after incorporating all ingredients.
The successful production of the present invention's composition relies on the skill of the manufacturer in
4 controlling and maintaining the final product's quality as required or specified.
The main parameters which must be controlled during the production are pH, in the range of 4 to 7, as well as a surfactant concentration of 5.5 to 7%, by weight, besides the viscosity which must be in the range of 400 to 1, 000 cP.
Comparative Examples
To confirm without doubt the superiority of the detergent composition of the present invention, compared to detergent compositions of the same character now commercially available, tables 1 and 2 were plotted - Evaluation Forms Based on Standardised Technical Rules - ASTM and ISO.
The tests used for the evaluation are based on the following standards:
(i) ISO 7535-1984-06-01 and (ii) ASTM D4009-92
A starch, protein, oil and carbohydrate mixture, in the following amounts, (1% by weight) was used as contaminants:
(a) 10% starch
(b) 7.25% protein (c) 11.75% oil
(d) 7.5% carbohydrate; and
(e) 63.5% water
The above contaminant represents, in whole, the soil resultant from the Brazilian food diet traditionally found in dishwashing operation, with water at room temperature.
The data collected are statistical resulting from comparison with commercially available dishwashing detergents (state- of-the-art) .
Other compositions containing the ingredients herein taught may be formulated by persons skilled in the art of detergents and the like, however, without departing from the scope as claimed in the present invention, which is represented by the attached claims.