NO139225B - DETERGENT MIXTURE. - Google Patents

Description

The object of the invention is a detergent mixture containing anionic or non-ionic surfactants and building salts, as well as possibly further additives.

It is known that the cleaning power of soaps and synthetic detergents in washing and cleaning products is increased by adding certain products. Such cleansing enhancers are referred to as building substances or "Builder". Building material-containing washing <p>g cleaners are more effective and even more cost-effective than the corresponding building material-free formulations.

The mechanism and details of the "builder effect" are

not yet completely settled. There are several processes that play a role in the function of builders such as stabilization of the pigment dirt suspensions, emulsification of dirt particles, influence of surface and interface properties of aqueous surfactant solutions, solubilization of water-insoluble components of the cleaning bath, peptization of dirt agglomerates, neutralization of acidic substances and inactivation of mineral substances in the washing bath.

In order to obtain information about the quality and properties of certain products as builders, their ratios and their effectiveness during washing or cleaning processes are appropriately examined. This ensures that all factors participating in the builder effect are taken into account qualitatively and quantitatively.

Classic builders are the water-soluble inorganic alkali salts, such as alkali carbonates, borates, phosphates, polyphosphates, bicarbonates and silicates.

Of the numerous products that are proposed as builders, the usual detergents and cleaners use almost exclusively the linear condensed phosphates or polyphosphates, especially penta-sodium triphosphate or sodium tripolyphosphate. The detergent and cleaning agent content of these building materials amounts to approx. 50% by weight.

Due to the considerable increase in consumption of phosphate-containing detergents and cleaning agents, both in households and in industry, the phosphate content of natural waste water has also increased. In the discussion about the increasing water neutrofation, the nitrates and phosphates have recently been attributed with properties that promote the growth of certain types of algae under certain conditions and thus can contribute to water neutrofation in this way. Although an unequivocal clarification of the importance of detergents and cleaning agents for water eutrophication is not yet possible, it seems that efforts should be made to develop potential nitrogen- and phosphorus-free replacement substances instead of the carrier substances currently used in normal detergent formulations, namely the polyphosphates.

The use of nitrogen- and phosphorus-free builders for detergent formulations is known. As such, starch derivatives, such as dicarboxyl and carboxymethyl starch, polycarboxylic acids such as polymaleic acid and their mixed polymers, oxydiacetic acid, oxydiacetic acid, esters of polyethylene glycol and adipic acid resp. maleic acid containing sulfonate groups, as well as esters of ethylene glycol and tri- or tetra-carboxylic acids. The use of the above-mentioned substances as carriers is associated with disadvantages which consist in the fact that these substances are either not sufficiently biodegradable or do not have sufficient dispersing power for hydrophilic dirt. In addition, economical methods for the production of these compounds are also partially lacking.

However, in addition to the surfactant component of a detergent formulation, whereby only hydrophobic dirt such as soot and fat particles are dispersed and/or peptized, the detergent must also contain a component which is suitable for removing hydrophilic dirt. This task belongs to the building materials. In the absence of such a building material, the dirt deposits on the fabric are only incompletely removed from the washing bath or there is a deposit of dirt particles on the sink, so that no satisfactory washing effect is achieved.

According to US patent 3,692,684, it is known to produce detergent compositions which, in addition to usual detergent components, contain an alkali salt of a carboxylic acid such as lactic acid, acetic acid, tartaric acid, citric acid, butanecarboxylic acid adipic acid and the like.

Furthermore, according to column 3, paragraph 2.. of the above-mentioned patent, the building effect of the above-mentioned salts can be improved by adding 0.5-25% by weight of sorbitol or pentaerythritol, referred to the amount of building salt.

As sorbitol and pentaerythritol are relatively expensive products and citric acid resp. its trisodium salt alone has no optimal building properties, the builders mentioned in US patent 3,692,684 cannot be attributed technical and economic importance.

With the builders mentioned in US patents 2,311,008 and 2,264,103 such as sorbitol acetate or acetylcitric acid, it is a disadvantage that the acetic acid components do not have building properties and thus only sorbitol or the citric acid to a limited extent is active as a builder.

The invention now relates to a detergent mixture containing anionic or non-ionic surfactants and building salts, as well as possibly further additives, the mixture being characterized in that the building salt contains 15-60% by weight, referred to the amount of dry matter of the washing and cleaning agent, of a water-soluble salt of glycerol tri-citrate. The detergent mixture according to the invention gives a pH value of from 8 to 12 in the aqueous environment of the washing bath.

Additives, which may possibly be contained alongside ion-active and/or non-ionic surfactants in the detergent formulation, include substances such as alkali or ammonium salts of sulfuric acid, silicic acid, di- and trisilicic acid, carbonic acid, boric acid, iminodiacetic acid, nitrilotriacetic acid, ethylenediaminetetraacetic acid, alkylenephosphonic acid , hydroxyalkylene phosphonic acid and/or aminoalkylene-r phosphonic acid, or stabilizers and activators for perborates as well as white toners, carboxymethyl cellulose, magnesium silicate, disinfectants and/or enzymes.

The carboxylic acid ester underlying the building salt according to the invention can be prepared according to known methods. ring procedures, for example by reaction of carboxylic acid with the alcohol by simultaneous distillation removal of the reaction water with the help of a drag agent. The molar ratio between carboxylic acid and alcohol is usually chosen so that per alcoholic hydroxyl group■ a molecule of carboxylic acid is available. If the carboxylic acid itself contains one or more alcoholic hydroxyl groups, these can also be esterified. It is important that the esterification removes per mole of carboxylic acid used one mole of reaction water from the esterification mixture. The acidic carboxylic acid ester formed is transferred by adding stoichiometric amounts of alkali in the corresponding water-soluble salt of the carboxylic acid ester.

The carrier substance according to the invention can be described as technical progress, as it significantly delays the precipitation of calcium ions in the washing bath and also forms stable dispersions with hydrophilic pigment particles. A further advantage is to be seen in its good biological degradability, whereby an enrichment of carrier substances in the waste water is avoided.

For assessing the building properties of the building materials according to the invention, for example its dispersing ability for iron (III) oxide, the binding ability for calcium ions and the washing power when washing an artificially soiled fabric are suitable. Similar experiments were carried out with building materials according to the invention and the results the toes compared to the properties of known building materials. Implementation of the experiments is explained in the following examples:

Attempt 1

The dispersing effect of the sodium salt of glycerol tricitrate (A) in an aqueous 4% by weight slurry of dry, powdered iron (III) oxide with a particle size of less than 0.058 mm was determined and compared to the effect of known carrier substances such as

B: trisodium citrate

C: glycerol

D: diacetin

D: sodium salt of ethylene glycol dicitrate

The possible concentration of building materials in the slurry amounted to 0.16% by weight, referred to the aqueous solution. As a measure of the dispersing effect, the deposition time of the iron oxide particles in 25 ml measuring cylinders was determined each time, as well as the sedimentation volume after 24 hours, as the slurry has a pH value of 10. The results obtained are summarized in Table 1:

Table 1 shows that the new carrier substance (A) disperses hydrophilic dirt particles better than the known carrier substances,

as the sedimentation volumes are smaller and the deposition time longer than for the two known carrier substances.

Attempt 2

The binding capacity for calcium ions was determined from the carrier substances mentioned in Example 1. The binding capacity for calcium ions in aqueous solutions is defined by the number indicating how many grams of calcium ions are held in solution by 100 g of carrier substance under certain conditions. The determination of this number takes place by titration with sodium carbonate, titrating the 1% sample solution adjusted to pH 10 with 0.1 normal calcium chloride solution until cloudiness appears. For the individual carrier substances, the measured figures listed in Table 2 for the binding capacity of calcium ions were determined:

Table 2 shows that the new carrier substance (A) in addition to the good dispersibility demonstrated in Table 1 also has a

good binding capacity for Ca<++-> ions, while the known carrier substances do not simultaneously have both properties to the above-mentioned extent.

Attempt 3

The washing power quotient of washing baths with a constant concentration of washing active substance, however with different amounts of it in Ex. 1 said carrier substance (A) according to the invention and the resulting results graphically displayed in fig. 1 in the form of curve A. For comparison, the analogous washing tests were carried out using those in Ex. 1 listed known carrier substances and the thereby formed washing power quotients likewise shown in fig. 1 in the form of curves B, D and E.

The washing tests were carried out with a standard cotton fabric with Krefelder soiling in a Launder-O meter at a washing bath temperature of 90°C. Standard weaving with Krefelder soil is defined in the book by Kurt Lindner "Tenside, Textilhilfsmittel-Wasch-rohstoffe", Wissenschafti. Verlagsgesellschaft Stuttgart (1964), Volume II, page 1837.

The washing water has a German hardness of 20° and a pH value of 10. The washing time was 30 minutes and the bathing conditions characterized by the ratio of (kg) laundry to (litres) washing bath, 1:50 in the presence of 10 steel balls. The washing bath contained 0.45 g/l dodecylbenzene sulphonate as washing active substance

0.15 g/l tallow fat alcohol and

0.15 g/l hardened tallow soap.

The concentration of the carrier substances constituted in the washing bath

0.2-2 g/l washing bath.

After the above-mentioned washing time, the standard cotton fabric was rinsed, once hot and once cold, and then measured in the emission photometer Elrepho from the company Zeiss for the degree of whiteness using filter R 53. The washing power was determined according to the difference method, for which the following equation is to reason:

In this equation means:

% WK = % washing power.

% WG = % whiteness content of the washed fabric %WGb = % whiteness content in unwashed fabric..

Of the curve sequence for curve A in fig. 1 shows that the carrier substance according to the invention gives the washing bath a higher washing power than the known carrier substances B, D and E.

Example

The procedure was analogous to Trial 3, however the following ingredients were additionally introduced into the wash bath: 0.15 g magnesium silicate/1 wash bath 0.15 g sodium silicate/1 wash bath

1.25 g "sodium perborate tetrahydrate/1 wash bath 0.45 g sodium sulfate/l wash bath

0.05 g carboxymethylgeilulose/1 wash bath.

The achieved washing effects are shown in the form of curves in fig. 2, as the curve progression for curve A shows the superiority of the carrier substance according to the invention in relation to the known carrier substances which were represented by curves B, D and E.

Preparation of the carrier substance A according to the invention: From a mixture consisting of 92 parts by weight of glycerol and 768 parts by weight of anhydrous citric acid with 250 parts by weight of toluene under constant circulation of the toluene, 72 parts by weight of reaction water, which arose during the esterification, were azeotropically distilled. After the mixture cooled, the toluene was separated from the ester. To prepare the sodium salt, the acidic ester was neutralized with 800 parts by weight of 40% caustic soda and the neutralization mixture was dried in a vacuum. The product formed was used in the example as carrier substance A.

Claims (1)

Detergent mixture containing anionic or non-ionic surfactants and building salts, as well as possibly further additives, characterized in that the building salt contains 15-60% by weight,' ref. to the amount of dry matter of