JP2562064C - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to concentrated liquid bleaching compositions suitable for sale and use as household bleaches. Pourable by containing one or more surfactants that, in the presence of the electrolyte, act to thicken the solution to a higher viscosity than water.
ble) Household bleaches are often thickened. Concentration of the pourable household bleach helps the user control the dispersion of the composition and delays discharge from the surface to which it is applied. SUMMARY OF THE INVENTION The present invention is directed to such compositions that include a surfactant and an electrolyte to increase viscosity. The compositions of the present invention may be pourable or may be of higher viscosity so as not to be easily pourable. Household bleaches need to be sufficiently stable so that most of the bleach does not lose its activity during storage between manufacture and use. Prior to the present invention, commercially available liquid bleaching products often utilized hypochlorite as a bleaching agent. It is well known that hydrogen peroxide is unstable in the absence of a stabilizer.
Stabilizers prevent decomposition catalyzed by transition metal ions. Hydrogen peroxide shows good bleaching action when used under alkaline conditions. However, stabilization of hydrogen peroxide under alkaline conditions was difficult, and commercial solutions of hydrogen peroxide were therefore generally acidic for stability. Certain phosphonates capable of stabilizing hydrogen peroxide in alkaline solutions are disclosed in EP-B-9839 (Unilever). The presence of the electrolyte tends to cause decomposition of the alkaline hydrogen peroxide solution.
For example, a 4% by weight solution of hydrogen peroxide rendered alkaline at pH 10 and containing 0.25% ethylenediaminetetramethylenephosphonic acid as stabilizer (not as effective as the phosphonate of EP-B-9839). Was found to retain 95% of its hydrogen peroxide after storage at 37 ° C. for 2 weeks. In contrast, 85% or less of the hydrogen peroxide remained if the solution contained 1% by weight sodium chloride, while about 50% if the solution contained 10% by weight sodium chloride. Only% hydrogen peroxide remained. Similar results were observed when using sodium tripolyphosphate rather than sodium chloride as the added electrolyte. Doubling the amount of phosphonate stabilizer has little effect on the rate of degradation. Thus, prior attempts to make surfactant-enriched alkaline household liquid bleach products using hydrogen peroxide as a bleaching agent have required the presence of certain electrolytes to concentrate the solution, This electrolyte could face the problem of helping to accelerate peroxide decomposition. However, the inventors have found that it is possible to formulate aqueous alkaline solutions of hydrogen peroxide that are concentrated with surfactants and electrolytes but still have sufficient stability to be used as commercial products. The present invention relates to an electrolyte other than hydrogen peroxide, a stabilizer thereof, and a surfactant, and an anionic surfactant that is either a C ₈ -C ₂₀ alkane sulfonate or a C ₈ -C ₂₀ alcohol sulfate. A concentrated liquid bleaching composition for a surface comprising an aqueous alkaline solution containing a surfactant selected from the group consisting of: a combination with an amphoteric surfactant. The use of the above surfactants has been found to be beneficial in achieving concentration at fairly low electrolyte concentrations. This allows the electrolyte to be provided by ions present in the composition for other reasons without the need to add salt solely for the sole purpose of increasing ionic strength. Apart from considerations for peroxide stability, the advantage of low electrolyte concentration is that it reduces the tendency of the product to leave streaks on the surface with which it is cleaned. If the surfactant is a combination of the above, those considered as preferred amphoteric surfactants include amine oxide surfactants, preferably one long chain alkyl having 8 to 20 carbon atoms and an alkyl having 1 to 4 carbon atoms. It is a trialkylamine oxide having two groups. At that time, when the primary alcohol sulfate is an anionic surfactant, the weight ratio of amine oxide to alcohol sulfate is preferably 82:18 to 65:35, and more preferably 80:20 to 65:35. , 80:20 to 70:30. Alkanesulfonates are preferred over alcohol sulfates. This is because the viscosity in that case is hardly affected by changes in the composition and it is easier to produce a final product with a reproducible viscosity. The weight ratio of amine oxide to alkane sulfonate (if used) is preferably in the range 80:20 to 50:50, or better still 80:20 to 65:35, and preferably 70:20 to 65:35. It is a narrower range of 30-65: 35. One or more additional surfactants may be included within the scope of the present invention. The total concentration of surfactant ranges from 0.75 to 6% by weight of the total composition, and may even be as narrow as 0.75 to 3% by weight, especially if the composition is pourable. Concentrations above 6% by weight are less preferred. The concentration of the electrolyte in the composition of the present invention is such that the total amount of salts other than the surfactant is 5% by weight or less, and more preferably 3% by weight or less. The electrolyte level is 0.05-
It may be 0.30 molar, preferably showing an electrolyte concentration in the range of 0.1-0.2 molar. Again, higher concentrations are less preferred. The stabilizer for hydrogen peroxide may be a phosphonate sequestration similar to that of EP-B-9839, which has the general formula: Wherein n = 1 to 4; X is H or a water-soluble cation selected from the group consisting of alkali metals, ammonium, substituted ammonium and alkaline earth metals. Such sequestering agents may be used in amounts of 0.01 to 1% by weight. It is about 1.5 × 10 ^-4 to 2 × 10 ^-2 mol. These compounds are effective in preventing ion-catalyzed decomposition, but are less effective against manganese. It has been found that additional stabilizers for manganese may not be needed because contamination by trace amounts of manganese can be prevented (eg using sufficiently pure raw materials). However, if necessary, another stabilizer inhibiting the action of manganese may be phosphate, used in an amount of 0.5 to 4% by weight, preferably 1 to 3% by weight (calculated as anhydrous salt). . Tetrasodium pyrophosphate may be used as such a salt. Another stabilizer that has been found to be effective in alkaline solutions against degradation caused by transition metals, including both iron and manganese, is colloidal stannic oxide hydrate. It is preferred to form this stabilizer in situ in solution as a product of hydrolysis of the soluble tin compound. Various tin compounds, including tin sulfate, sodium stannate, tin dichloride and tin tetrachloride, may be added to the solution and hydrolyzed to form stannic oxide. A suitable concentration of the tin compound in the composition is between 10 ^{-4 and} 10 ^-2 mol, preferably 3 × 10 ^-3.
It may be in the range of ６6 × 10 ^-3 mol. The amount of tin compound should not actually be more than necessary, as the excess itself can cause peroxide decomposition.
The optimal concentration of the tin compound (or any stabilizer) can be determined by testing the solution with various concentrations of stabilizer and analytically measuring the amount of hydrogen peroxide remaining after the storage period. it can. Suitable viscosities for pourable compositions having the appearance of a concentrate are 40 to 250 centipoise (0 to
.05 to 0.25 Pa.s), preferably about 100 centipoise (0.1 Pa.s).
) Viscosity. High viscosity liquids having a viscosity of 250-1000 centipoise or more are also within the scope of the present invention. Since the compositions of the invention are generally aqueous, they usually have a specific gravity close to 1. Therefore, the kinetic viscosity value (Stokes) is numerically almost the same as the dynamic viscosity value (Poise). The dynamic viscosity expressed in Pascal-second is almost 1000 times the kinematic viscosity expressed in m ² -second ^-1 . The pH of the solution is 8.0 to 10.5, and better still 8.5 to 9.8 or 8.5 to 10.0. If a phosphonate stabilizer is used, it is more preferably in the narrower range of 9.2-9.8, whereas if colloidal stannic oxide is used as stabilizer, a slightly lower pH in the range of 8.7-9.3. It is preferable to use Buffers may be included to maintain the pH at the desired value, but this may not be necessary. Phosphate, when present, exhibits a buffering effect. Another compound that can be used for this purpose is borax. The concentration of hydrogen peroxide in the composition of the present invention, calculated as pure H ₂ O _2, 1 to 15 wt%, preferably from 2 to 10 wt%. Example 1 A formulation containing the components shown in Table 1 below was prepared. The composition was stored at 37 ° C. in a plastic bottle. From time to time, aliquots were removed and titrated with potassium permanganate to determine the level of residual hydrogen peroxide. Table 1 shows the results. The viscosity of these formulations was measured using a Ubbelohde capillary viscometer and was approximately 100
turned out to be cS. Example 2 The procedure of Example 1 was repeated using a formulation containing the same amounts of hydrogen peroxide, surfactant, fragrance and dye. Various tin compounds were used at a concentration of 6 × 10 ^-3 molar, both with and without 3% borax decahydrate. A glass bottle was used, which is somewhat harmful for stability. In all cases, the pH was initially 9.6.
Met. The percentage of hydrogen peroxide remaining after 28 days was as follows: Borax and SnCl ₂ 68% Borax and Na ₂ SnO ₃ 47% Borax and SnSO ₄ 45% Na ₂ SnO ₃ (no borax) 96% SnCl ₄ was prepared (borax none) 68% example 3 a range formulations, it all contained the following: hydrogen peroxide 5.0% (calculated as anhydride) tetrasodium pyrophosphate 10 hydrated Thing 3.0%
(Approximately 1.8% calculated as anhydride) Phosphonate stabilizer of EP 9839 0.3% Fragrance 0.1% Sodium hydroxide Concentrating system up to pH 9.6 Various water used The remaining 100% Concentrating system Various components were used, but varied in the properties and total amounts of the materials used. Thickening system was sodium lauryl sulfate (SLS) or sodium alkane sulfonate (SAS) (which is essentially secondary alkane sulphonate derived from n- alkane mixtures of C ₁₃ -C ₁₈ ) Containing tallow dimethylamine oxide (AO). The viscosity of the formulation was measured using a Ubbelohde capillary viscometer. The results obtained are shown in the accompanying drawings. FIG. 1 shows the variation in viscosity with respect to the proportion of SLS in the AO / SLS mixture when the total amount of AO + SLS was varied from 1.1% to 1.9% by weight of the composition. FIG. 2 shows the variation in viscosity for an AO / SAS mixture when the total amount of AO + SAS was varied from 1.2% to 2.6% by weight of the composition. It is observed that the viscosity peak is broad and the maximum viscosity is hardly affected by the variation of the total amount of AO + SAS. For example, in FIG. 1, the concentration of surfactant to have a viscosity of 100 cS is 1.2%, and increasing from 0.2% to 1.4% doubles the viscosity to 200 cS. In FIG. 2, 1.4% of total surfactant shows a viscosity of 100 cS. Increasing by 0.2% increases the viscosity to 150 cS, but to reach 200 cS, it must be further increased to 1.8%.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the variation in viscosity with respect to the proportion of SLS in the AO / SLS mixture when the total amount of AO + SLS was varied from 1.1% to 1.9% by weight of the composition. FIG. 2 shows the variation in viscosity for an AO / SAS mixture when the total amount of AO + SAS was varied from 1.2% to 2.6% by weight of the composition.

Claims (1)

Claims: (1) 1 to 15% by weight of hydrogen peroxide, 0.01 to 4% by weight of a stabilizer against hydrogen peroxide, 0.05 to 0.30 mol and 5% by weight or less of an electrolyte other than a surfactant , and 0.75 to 3 wt%, contains a combination of a C ₈ -C ₂₀ anionic surfactant is either alkanesulfonate or C ₈ -C ₂₀ alcohol sulfates and amphoteric surface active agents, and A concentrated liquid bleaching composition for a surface comprising an aqueous alkaline solution having a pH of 8.0 to 10.5 having a total amount of surfactant of 6% by weight or less. (2) The composition according to claim 1, wherein the stabilizer is colloidal stannic oxide hydrate. (3) The stabilizer has the formula: 2. The compound of claim 1, wherein n = 1 to 4; X is H or a water-soluble cation selected from the group consisting of alkali metals, ammonium, substituted ammonium and alkaline earth metals. Composition.