EP0063503A1 - Activating composition for peroxide bleaching - Google Patents

Abstract

An activating composition for bleaching textiles with peroxide products, containing an activator of the cyanamide type or derivative thereof, further contains a ternary protective mixture comprising a magnesium silicate precipitated in the finely divided powder state, a sequestering agent of the acetic type, preferably organoacetic, and a sequestering agent of the phosphonic type, preferably organophosphonic. The composition finds its application in activation of bleaching at moderate temperature with protection of textile fibers, of household washing powders at moderate temperature (30 DEG to 60 DEG C.) or any temperature (up to 90 DEG C.).

Description

The present invention relates to an activating composition for bleaching at moderate temperature, in particular intended for detergents and detergents containing, as bleaching agent, peroxidized products capable of releasing active oxygen.

Bleaching agents that generate liquid active oxygen such as hydrogen peroxide or solids such as persalts such as sodium perborate, do not decompose at a speed fast enough to be compatible with a bleaching process, except at a temperature above 60 ° C.

However, household detergents at moderate temperature are a subject on the agenda linked to the problem of energy saving. In addition, the implementation in a washing machine of an effective bleaching process at a temperature below 60 ° C has a number of advantages. In the case of cotton fabrics, there is less degradation of the cellulose, and consequently a reduction in the wear of the linen. Improved bleaching is observed - synthetic fabrics or textile articles treated with a finish ensuring their wrinkle-resistant and permanent ironing, and which cannot withstand a temperature above 60 ° 0. Bleaching at moderate temperature reduces the risk of attack of the dyes or their transfer from one fabric to another. This type of bleaching is also in favor of the fight against pollution by lowering the polyphosphates content of waste water.

French patent 2,340,371 discloses a process for activating a peroxide-based bleaching agent, in which is incorporated into an aqueous medium: (a) a peroxide-based bleaching agent, (b) cyanamide and / or a metallic cyanamide in an amount suitable for activating the peroxide, and optionally (c) a group II metal compound, and the aqueous medium is maintained in an alkaline state, optionally by incorporating a buffer, with the condition that if component (b) is cyanamide and if component (c) is absent, the aqueous medium is maintained at a pH greater than 7.5.

However, it has been found that bleaching in the presence of an activator of the cyanamide type causes a certain depolymerization of textile polymers and in particular of cellulose fibers.

The degradation observed is particularly accentuated when the washing temperature exceeds 60 ⁰ 0, and especially when it reaches 90 ° C; the temperature of 90 ° C is a relatively frequent case in the case of all temperature laundry. At 90 ° C, the depolymerization is such that it causes a degradation likely to accelerate the wear of the cotton linen during successive washes.

On the other hand, although the prior teaching has proposed ethylenediaminetetraacetic dimagnesium as constituent ( ₀ ) of the activating composition, it has been observed that this adjuvant, under the prescribed conditions of use has practically no effect on the observed degradation of cellulosic fibers.

French patent 2,140,213 proposes as stabilizing agent a combination of 1-hydroxyethylidene -1,1-diphosphonic acid and its water-soluble salts, nitrilotriacetic acid and its water-soluble salts and a water-soluble salt chosen from magnesium salts, calcium salts. Tests have shown that this stabilizing agent is not suitable for effective protection of the cellulose against the aggressiveness of cyanamide.

A protective composition has been sought which makes it possible to reduce the aggressiveness of cyanamide vis-à-vis cellulosic fibers while retaining its performance in activating peroxidized compounds.

A protective composition has been found which significantly reduces the degradation effect of cellulosic fibers by cyanamide and its derivatives, while in no way limiting the effectiveness of the bleaching obtained by activation of the compounds peroxidized by cyanamide and its derivatives.

This protective composition, which has no adverse effect on the bleaching results, makes it possible to reduce the aggressiveness of cyanamide to that of ethylenediaminetetra-acetyl TAED. With the new composition, obtaining equivalent bleaching results and the degree of polymerization was found possible between TAED at 0.6 g / liter and calcium cyanamide CaNCN at 0.2 g / liter.

Given that calcium cyanamide is an activator approximately three times more active than ethylene diaminetetraaoetyl TAED, and that on the other hand, cyanamide is of a much lower cost than TAED, one perceives all the economic interest of the present activating composition.

The activating composition for bleaching contains an activator of the cyanamide type and its derivatives, alone or in a mixture for activating bleaching by means of peroxidized products at temperature moderate; it also contains a ternary protective mixture, with synergistic effect comprising a magnesium silicate in the finely divided powder state, a sequestering agent of the acetic type, preferably organoacetic, and a sequestering agent of the phosphonic type, preferably organophosphonic.

It has been found that the ternary protective mixture provides the most effective protection although the concentration of each constituent is lower, either than each constituent used alone, or than the binary mixtures thereof, consequently, the combination of the three components has a clearly marked synergistic effect.

The acetic sequestrants are nitrilotriacetic, hexamethylenediaminetetraacetic, ethylene diaminetetraacetic and, preferably diethylenetriaminepentaacetic.

The phosphonic sequestrants are nitrilomethylene-phosphonic, ethylenediaminetetramethylenephosphonic, preferably diethylene triaminopentamethylenephosphonic.

The acetic and phosphonic sequestrants are chosen in the form of free acid or of alkali or alkaline earth metal salts.

Very advantageous results have been obtained by using the activating composition constituted by calcium cyanamide and / or its derivatives and the protective mixture comprising magnesium silicate precipitated in the form of finely divided powder, and in the form of a magnesium complex, the diethylenetriaminepentaacetic acid and diethylenetriaminepentamethylenephosphonic acid.

The cyanamide derivatives are the cyanamide of alkali or alkaline earth metals, preferably calcium cyanamide, magnesium laoyanamide or sodium cyanamide.

The activating composition is intended to be incorporated into detergents, in particular household powder detergents for washing laundry and its bleaching at moderate temperature.

On the other hand, it is important for the effectiveness of the activating composition that it is dispersed in a homogeneous manner in the powdered detergent and in a form which allows its homogeneous distribution in the detergent bath. As regards, for example, the sparingly soluble compounds of cyanamide, in particular calcium cyanamide, it is advantageous to use a powder of less than 100 microns.

The finely divided calcium cyanamide powder is homogenized using a conventional powder mixer, in the powder of precipitated magnesium silicate already containing the acetic sequestrant and the phosphonic sequestrant.

The phosphonic sequestrant and the acetic sequestrant are incorporated into the magnesium silicate, preferably during the manufacturing process of the magnesium silicate; they can also be incorporated after its manufacture.

The activating composition comprises a protective mixture based on precipitated magnesium silicate in which is incorporated in the form of a magnesium complex of 3 to 30%, preferably 5 to 15%, of an acetic type sequestrant and of 5 to 50%, preferably 8 to 25% of a phosphonic type sequestrant, the proportions being indicated by weight relative to the magnesium silicate.

It has been found advantageous that the activating composition contains from 20 to 150%, preferably 30 to 100% by weight, of activator of the cyanamide type and derivatives with respect to the protective mixture representing 100%.

Very good results have been obtained using the activating composition at a concentration in the detergent bath of between 0.2 and 1 gram per liter, preferably between 0.4 and 0.8 g per liter.

Non-limiting examples are given below which illustrate the results and advantages of the invention.

• - CaNCN : cyanamide calcique blanche à 96 % de pureté, de granulométrie inférieure à 100 microns ;
• - Si0₃Mg: Silicate de magnésium précipité ayant une surface spécifique de 250 m2/g environ ;
• - TAED : Ethylène diaminetétraacétyle ;
• - Produit vendu sous la marque commerciale "Dequest 2060" : acide diéthylènetriaminepentaméthylènephosphonique ;
• - Produit vendu sous la marque commerciale "Versenex 80" : sel de sodium de l'acide diéthylènetriamine pentaacétique, en solution à 40 % de produit actif, DTPA ;
• - Produit vendu sous la marque commerciale "Vérsène 100" : sel de sodium de l'acide éthylènediaminetétraacétique en solution à 40 % de produit actif ;
• - EDTA (Mg) : sel de magnésium de l'acide éthylènediaminetétraacétique, à 70 % de produit actif ;
• - Produit vendu sous la marque "Dequest 2010" acide hydroxyéthylidène diphosphonique ;
• - DTPMP : acide diéthylène triamine pentaméthylène phosphonique.

Definitions and characteristics of the products used in the various tests:

• - CaNCN: white calcium cyanamide with 96% purity, particle size less than 100 microns;
• - Si0 ₃ Mg: precipitated magnesium silicate having a specific surface of 250 m2 / g approximately;
• - TAED: Ethylene diaminetetraacetyl;
• - Product sold under the trademark "Dequest 2060": diethylenetriaminepentamethylenephosphonic acid;
• - Product sold under the trademark "Versenex 80": sodium salt of diethylenetriamine pentaacetic acid, in 40% solution of active product, DTPA;
• - Product sold under the trademark "Vérsène 100": sodium salt of ethylenediaminetetraacetic acid in solution at 40% of active product;
• - EDTA (Mg): magnesium salt of ethylenediaminetetraacetic acid, with 70% of active product;
• - Product sold under the brand name "Dequest 2010" hydroxyethylidene diphosphonic acid;
• - DTPMP: diethylene triamine pentamethylene phosphonic acid.

Example 1

Whitening tests without protective composition.

A detergent bath is prepared from tap water to which an ECE detergent, sodium perborate and an activator are added. ECE detergent has the following composition in percentage by weight:

• - 2 échantillons de 10 x 10 cm salis de vin;
• - 2 échantillons de 10 x 10 cm salis de thé;
• - 2 échantillons de 10 x 10 cm salis de café.

We use a Terg-0-Tometer device containing 1 liter of detergent bath, in which we place:

• - 2 samples of 10 x 10 cm soiled with wine;
• - 2 samples of 10 x 10 cm soiled with tea;
• - 2 samples of 10 x 10 cm soiled coffee.

The samples for the study of cellulose degradation were taken from a cotton fabric, reference EMPA 301 used in the textile and bleaching industry supplied by the Federal Laboratory for Materials Testing of the Research Institute. from St GALL in SWITZERLAND, whose initial degree of polymerization (DP) is 2,000.

Six washing tests are carried out, over a period of 40 minutes, including the rise in temperature, the stirring being adjusted to 60 revolutions per minute. The washing conditions and the results are collated in Table 1 below; the degree of polymerization is determined after five successive washes at 90 ° C.

From the reading of this table, it follows that after a succession of five washes at 90 ° C. with ECE detergent alone, no reduction in the degree of polymerization of the fabric is observed. After the same succession of washes in the presence of 1.5 g of sodium perborate, depolymerization is practically non-existent. It is observed, on the other hand, that TAED (ethylenediaminetetracetyl) has a very weak depolymerization effect. On the other hand, calcium cyanamide (CaNCN) has a very marked effect, since the degree of polymerization is only 1400 when the CaNCN concentration is 0.3 g / l. It is also observed that the calcium cyanamide at 0.2 g / l gives a percentage of stain removal roughly equivalent to that of the TAED at 0.6 g / l; which would seem to mean, as a first approximation, that calcium cyanamide has an activation power at 30 and 60 ° C about three times that of TAED.

Example 2

Performing a series of 13 put bleaching tests performed with the products or protective compositions under the same conditions as test n ⁰ 6 of Table 1, that is to say with 0.3 g / l cyanamide .

The results of these thirteen tests are shown in Table 2 below; the degree of polymerization of the cotton is determined after five successive washes at 90 ° C.

The compared results of this table show that the magnesium silicate exerts a sensitive protective effect, roughly equivalent to that of the sodium salt of diethylenetriaminepentaacetic acid, ("Versenex 80") and the sodium salt of ethylenediaminetetraacetic acid. ("Versène100") at 0.09 g / l. The mixture of magnesium silicate + sodium salt of diethylenetriaminepentaacetic acid (test 15) has a slightly more marked effect; however the protective effect of diethylenetriaminepentamethylenephosphonic acid ("Dequest 2060") is still greater than that of the Si0 ₃ Mg + "Versenex 80" mixture of test 15; and the protective effect of the mixture of magnesium silicate + diethylenetriaminepentamethylenephosphonic acid ("Dequest 2060") is clearly enhanced.

Finally, we note that the ternary mixture of magnesium silicate + sodium salt of diethylenetriaminepentaacetic acid + diethylenetriaminepentamethylenephosphonic acid provides the most effective protection although the concentration of each constituent is lower, either with each constituent used alone, or with binary mixtures . Consequently, it appears that the combination of the three components has a markedly synergistic effect.

Example 3

New bleaching tests were carried out with protective agents or protective compositions under the conditions identical to those of Test N ⁰ 5 in Table 1 with 0.2 g / 1 of calcium cyanamide.

The results of these tests are recorded in the table below, the degree of polymerization is determined after five successive washings at 90 ° C.

It is noted that the magnesium silicate exerts a protective effect superior to that of the sodium salt of ethylenediaminetetraacetic acid ("Versene 100") and of the magnesium salt of ethylenediaminetetraacetic acid. On the other hand, diethylenetriaminepentamethylenephosphonic acid ("Dequest 2060") has a protective action little superior to that of magnesium silicate when used at 0.04 g / l. The protective effect of the binary mixture of magnesium silicate + sodium salt of diethylenetriaminepentaacetic acid ("Versenex 80") is slightly greater than that of magnesium silicate alone (test 25). Test 26 shows that the protective power of magnesium silicate is clearly reinforced by the addition of diethylenetriaminepentamethylenephosphonic acid.

However, test 27, once again reveals that the ternary mixture of magnesium silicate + diethylenetriaminepentaacetic acid (Na) + diethylenetriaminepentamethylenephosphonic acid, has the best protective effect although each component is used at a concentration equal to or less than that of the tests in which it is used alone or in binary mixture.

On the other hand, it is noted that the degree of polymerization of cotton treated in the presence of the ternary mixture (1900) is the same as in Test ^No. 4 in Table 1 with 0.6 g / l éthylènediaminetétracétyle (TAED) . This shows that with the ternary composition with synergistic effect, it is possible to obtain bleaching results and equivalent degree of polymerization between TAED at 0.6 g / l and cyanamide at 0.2 g / l.

Comparative example 4:

Demonstration of the protective effect of a ternary protective mixture according to the invention compared to the combination described in French patent 2,140,213.

This patent cites a stabilizing composition consisting of a 36.1% solution of 1 mole of nitrilotriacetic acid (NTA), 0.47 mole of magnesium salt, originating from a soluble salt, for example magnesium sulfate and 0.3 mole of 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP).

• 29 % NTA à 90 % (acide NTA)
• 15,8 % MgSO₄, 7H₂O
• 14,1 %HEDP à 60 % (Dequest 210)

This composition applied to the invention and prepared in the form of a solution contains:

• 29% NTA to 90% (NTA acid)
• 15.8% MgSO ₄ , 7H ₂ O
• 14.1% HEDP at 60% (Dequest 210)

• 84,7 % Silicate de magnésium
• 6,8 % DTPA (sel de sodium de l'acide diéthylène triamine pentaacétique expression 100 %)
• 8,5 % DTPMP (acide diéthylène triamine pentaméthylène phosphonique).

The composition according to the invention in the case of this comparative test is as follows:

• 84.7% Magnesium silicate
• 6.8% DTPA (sodium salt of diethylene triamine pentaacetic acid expression 100%)
• 8.5% DTPMP (diethylene triamine pentamethylene phosphonic acid).

In order to evaluate the protection efficiency of the cellulose provided by each of these stabilizers, successions of washes were carried out in an AHIBA device on the one hand and in a Terg-0-Tometer device on the other hand.

The degradation of the cellulose was determined on EMPA 301 fabric, reference fabric supplied by the Federal Laboratory for Materials Testing and Research Institute of St GALL in SWITZERLAND. The initial degree of polymerization (DP) of this fabric was 2400. Test A: 15 washes were carried out in an AHIBA machine of 15 g of EMPA 301 fabric in 600 ml of washing bath, the compositions of which are mentioned in the table 4 below. The total duration of each wash is 40 min, including 30 min to rise from 25 to 90 ° C, and 10 min at a temperature of 90 ^° C. The samples are rinsed under the usual conditions between each wash.

The results obtained show that the components contained in the detergent in a usual manner are not effective enough to avoid significant degradation of the cellulose. It is therefore essential to accompany the addition of activator to calcium cyanamide with a cellulose protector.

Comparison of the degrees of polymerization between the results obtained in test A ₂ in the presence of cyanamide and in tests A ₆ and A ₇ in the presence of the protective mixture according to the invention and tests A ₉ and A ₁₀ according to the French patent 2.140.213, shows the superiority of the effectiveness of the protection of the new protective mixture.

Trial B

Successive 10 washes in a Terg-0-Tometer machine were carried out with a detergent containing no magnesium silicate. 15 g of EMPA 301 fabric were used in 1 liter of washing bath, the compositions of which are given in table 6. As previously, the total duration of each washing was 40 minutes, of which 30 minutes were used to increase from 25 to 90 ° C and 10 minutes at 90 ° C.

These results confirm the effectiveness of the protective mixture of the invention compared to that of the prior art.

Table 7 below shows that doubling the dose of use of the protective mixture of the prior art does not allow to approach the effect of the new protective mixture. The comparison is made between test B ₂ ( _{DP 1120} ) and tests B ₃ (DP 2120), ^B ₄ and B ₅ (1350 and 1550).

Claims (11)

1 - Activating composition for bleaching, using peroxidized products, containing an activator of the cyanamide type and derivatives, characterized in that it also contains a ternary protective mixture comprising a magnesium silicate precipitated in the finely powdered state divided, an acetic type sequestrant and a phosphonic type sequestrant. 2 - Activating composition for bleaching according to claim 1, characterized in that the acetic sequestrant is of the organoacetic type and the phosphonic sequestrant is of the organophosphonic type. 3 - Activating composition for bleaching according to claim 1 or 2, characterized in that the acetic sequestrant is nitrilotriacetic, hexamethylenediaminetetraacetic, ethylenediaminetetraacetic, diethylenetriaminepentaacetic, in free acid form or of alkali and alkaline earth metal salts , the phosphonic sequestrant is nitrilotrimethylenephosphonic, ethylenediaminetetramethylenephosphonic and diethylenetriaminopentamethylenephosphonic in free acid form or of alkaline and alkaline-earth salts. 4 - Activating composition for bleaching according to claim 1 or 2, characterized in that the acetic sequestrant is diethylenetriaminepentaacetic in free acid form or of alkali and alkaline earth metal salts, the phosphonic sequestrant is diethylenetriaminopentamethylenephosphonic in free acid form or of alkali and alkaline earth metal salts. 5 - Activating composition for bleaching according to any one of claims 1 to 4, characterized in that the cyanamide derivatives are the cyanamide of alkali and alkaline earth metals, calcium cyanamide, magnesium cyanamide and monosodium cyanamide. 6 - activating composition for bleaching according to any one of claims 1 to 5, characterized in that it contains as activator calcium cyanamide and a protective mixture consisting of magnesium silicate precipitated in the form of finely divided powder and in the form of a magnesium complex, diethylenetriaminepentaacetic acid and diethylenetriaminepentamethylenephosphonic acid. 7 - activating composition for bleaching according to any one of claims 1 to 6, when the cyanamide derivative is poorly soluble, such as calcium cyanamide, characterized in that the particle size of calcium cyanamide is less than 100 microns. 8 - activating composition for bleaching according to any one of claims 1 to 7, characterized in that the protective mixture based on magnesium silicate contains in the form of magnesium complex from 3 to 30% of a sequestering agent of acetic type and 5 50% of a phosphonic type sequestrant, the proportions being indicated by weight relative to the magnesium silicate. 9 - Activating composition for bleaching according to claim 8, characterized in that the protective mixture based on magnesium silicate further contains in the form of a magnesium complex of 5 to 15% of a sequestering agent of acetic type and 8 to 25 % of a phosphonic type sequestrant, the proportions being indicated by weight relative to the magnesium silicate. 10 - activating composition for bleaching according to any one of claims 1 to 9, characterized in that the composition contains from 20 to 150% by weight, preferably 30 to 100% by weight, of activator of the cyanamide type and derivatives with respect with the protective mixture representing 100%. 11 - Activating composition for bleaching according to any one of claims 1 to 10, characterized in that the concentration of said composition in the detergent bath is between 0.2 and 1 g per liter, preferably between 0.4 and 0 , 8 g per liter.