JPS6119678B2 - - Google Patents

Abstract

The invention pertains to aqueous liquid detergent compositions having improved non-corrosive properties which comprise an effective amount of silica having a surface area greater than 200 m<2>/gram. The inclusion of silica provides good non-corrosive properties both in respect to metal and enamel surfaces.

Description

[Detailed description of the invention]

The present invention relates to liquid detergent compositions, particularly aqueous liquid detergent compositions having improved non-corrosive properties. Antioxidants are included in the detergent composition to counteract the corrosive and discoloring effects of cleaning liquids on metal or enamel parts of cleaning machines and thereby prevent deterioration of machine performance or discoloration of textiles in contact with such corroded parts. It is desirable to include a caustic agent. Aqueous liquid detergent compositions containing corrosion inhibitors are known in the art. Commonly used are soluble silicates such as metasilicates, orthosilicates and sesxylilicates. Apart from their anti-corrosive action, such compounds give liquid detergent compositions a highly alkaline environment, which is not always a desirable situation;
This is particularly the case when alkali-sensitive ingredients are used in such compositions. Further added corrosion inhibitors described in the detergent technology category include sulfites, nitrites, carbonates, borax or organic compounds such as benzoates. It has now been discovered that the corrosive effects of aqueous liquid detergent compositions can be significantly reduced by incorporating such types of silica in amounts that establish a certain critical concentration of dissolved silica in the wash water. The present invention thus provides aqueous liquid detergent compositions having improved non-corrosive properties that include conventional detergent ingredients and an effective amount of silica of the type hereinafter defined. To achieve optimal anti-corrosion protection, silica should be present in dissolved form in the cleaning solution at least 120% by weight.
It has now been found that it must be present in a concentration of ppm and preferably 150 ppm by weight. Accordingly, in accordance with the present invention, generally from about 1 to 10%, preferably from 1.5 to 10% by weight of the liquid detergent composition, to provide the required amount of dissolved silica in the cleaning liquid to ensure adequate anti-corrosion protection. Silica will be incorporated into the liquid detergent composition in an amount corresponding to up to 5% by weight and most preferably from 2 to 4% by weight.
This amount is then intended to be used at a product dosage of 10 g/ft during washing. If a liquid detergent composition is formulated with a preferred in-cleaning product dosage different from 10 g/d, the amount of silica to be incorporated to achieve adequate anti-corrosion protection will therefore be The amount must be adjusted so that it corresponds to the range as specified for 10 g/dose. The silica to be used in the invention should have a surface area of greater than 200 m ² /g and preferably greater than 350 m ² /g or even 500 m ² /g. Although the upper limit of surface area is not a critical factor, surface areas typically range up to about 1200 m ² /g. Generally, such silica has a particle size of less than about 30 nm, particularly less than about 25 nm. Preferably the particle size is less than 20 nm or even 10 nm. There is no critical low limit for particle size; the low limit is constrained by other factors such as manufacturing practices. Generally, commercially available silica has a particle size of 1 nm or more. Suitable forms of silica include precipitated silica, amorphous silica such as pyrogenic silica, silica gel such as hydrogels, xerogels and aerogels, or pure crystalline forms of quartz, lepidolite or cristobalite, but amorphous silica of the form is preferred. Suitable silicas are readily available commercially. They are, for example, Aerosil 380
(from Degussa Corp., NJ, USA), Cab-O-
Sil M5 (from Cabot Corp., I 11, USA),
Tixosil 38A (from SI Chimie, France) and
Sold under the registered trade name Gasil 200 (from Crosfield, UK). The liquid detergent compositions of the present invention contain as essential ingredients active detergent materials, which can be alkali metal or alkanolamine soaps of _C10 - _C24 fatty acids, polymerized fatty acids, or anionic, nonionic, cationic, Contains zwitterionic or amphoteric synthetic detergent materials, or mixtures of any of these. Anionic synthetic detergents are synthetic detergents of the sulfate- and sulfonate type. Their examples are C ₉ −C ₂₀
Salts of alkyl benzene sulfonates (including sodium, potassium, ammonium and substituted ammonium salts such as mono-, di- and tri-ethanolamine salts), C ₈ -C ₂₂ primary or secondary alkane sulfonates, C ₈ -C ₂₄ Olefin sulfonates, e.g. British Patent Specification no.
Sulfonated polycarboxylic acids, _C8 - _C22 , prepared by sulfonation of the pyrolysis products of alkaline earth metal citrates as described in No. 1082179.
Alkyl sulfates, _C8 - _C24 alkyl polyglycol ether sulfates (containing up to 10 moles of ethylene oxide); further examples in "Surfactants and Detergents" by Schwartz, Perry and Berch (and volumes) It is described in. Examples of non-ionic synthetic detergents are ethylene oxide, propylene oxide and/or butylene oxide and C ₈ -C ₁₈
Alkylphenols, _C8 - _C18 primary or secondary aliphatic alcohols, condensation products with _C8 - _C18 fatty acid amides; further examples of non-ionic detergents include tertiary amine oxides and one Contains a _C8 - _C18 alkyl chain and a condensate with two _C1 - _C3 alkyl chains. The above references also describe further examples of nonionic detergents. The average number of moles of ethylene oxide and/or propylene oxide present in the above nonionic detergent is 1
mixtures of various nonionic detergents can also be used, including mixtures of nonionic detergents and highly alkoxylated products. Examples of cationic detergents are quaternary ammonium compounds such as alkyl dimethyl ammonium halides. Examples of amphoteric or zwitterionic detergents are N-alkyl amino acids, sulfobetaines and condensation products of fatty acids with protein hydrolysates, but because of their relative cost they are usually combined with anionic or nonionic detergents. used. Mixtures of various types of active detergents can also be used, and anionic and nonionic detergent-active compound mixtures are preferred. Soaps (in the form of their sodium, potassium, and substituted ammonium salts, such as salts of polymerized fatty acids) can also be used, preferably with anionic and/or nonionic synthetic detergents. The amount of active detergent material is from 1 to 60%, preferably from 2 to 40% and particularly preferably from 5% by weight.
It varies from 25% to 25%. If soap is included, its amount is from 1 to 40% by weight. Although not essential, the liquid compositions of the invention preferably also contain up to 60% of suitable builder substances, such as sodium, potassium and ammonium or substituted ammonium pillows and tri-polyphosphates, -ethylenediamine tetraacetate, -nitrilotri- Acetate, -
Ether polycarboxylate, -citrate, -carbonate, -orthophosphate, zeolite, carboxymethyloxysuccinate,
Including etc. Particularly preferred are polyphosphates.
builder salts, nitrilotri-acetates, citrates, zeolites, and mixtures thereof. Generally the builder is present in an amount of 1 to 60%, preferably 5 to 50% by weight of the final composition. The amount of water present in the detergent compositions of the invention varies from 10 to 70% by weight. Other conventional substances may also be present in the liquid detergent compositions of the present invention. Sequestering agents such as ethylenediaminetetraphosphonic acid; non-builder electrolytes such as alkali metal chlorides, bromides, nitrates and sulfates; sodium carboxymethyl cellulose, polyvinyl pyrrolidone or maleic anhydride/vinyl Foul anti-settling agents such as methyl ether copolymers; hydrotropes; dyes; fragrances; alkaline substances such as silicates; fluorescent brighteners; disinfectants; antifogging agents; suds enhancers; liquid polysiloxane anti-foaming compounds suds suppressants such as; enzymes, especially subtilisins available on the market;
Maxatase (Gist-Brocades NV, Delft,
from The Netherlands), Alcalase and
Esperase (both Novo Industri A/S,
proteolytic, amylolytic and fibrinolytic enzymes such as (from Copenhagen, Denmark); enzyme stabilization systems such as mixtures with polyometal borates;
Oxygen liberating bleaches such as diperisophthalic anhydride with or without bleach precursors such as sodium perborate or sodium percarbonate, tetraacetyl ethylene diamine; or chlorine liberating bleaches such as dichlorocyanurate. agents; antioxidants such as sodium sulfite; opacifiers; fabric softeners; stabilizers such as polysaccharide hydrocolloids, such as partially acetylated xanthan gum, "Kelzan" (Kelco Comp., New Jersey,
commercially available from USA); buffers and the like. The invention is further illustrated by the following examples, in which parts and percentages are by weight unless otherwise indicated. EXAMPLE The following composition was made: Ingredients: % Sodium Dodecyl Benzene Sulfonate
5.0 C ₁₃ -C ₁₅ linear primary alcohol condensed with 7 moles of alkylene oxide (92:8 weight ratio mixture of ethylene oxide and propylene oxide) 2.0 Anhydrous sodium tripolyphosphate 21.0 Amorphous silica (raw) Particle size 10nm, surface area 700m ² /
g) 3.0 Sodium carboxymethyl cellulose 0.2 Foam suppressant 0.3 Fluorescent brightener 0.1 Stabilizer 0.2 Proteolytic enzyme ^* Enzyme stabilizer 10.0 Flavor 0.25 Water Remaining PH 8.0 *The final product of the enzyme has a proteolytic activity of 9GU/mg
(733 GU/mg = 1 Anson unit/g). In order to demonstrate the anti-corrosion effect of the composition of the present invention, comparative tests were carried out on the said composition under various temperature conditions and degrees of water hardness. Al - Corrosion Test In order to evaluate the corrosive effect of the test cleaning solution, a 40 cm ²
A pure aluminum (99.5% Al) disk with a surface area of 100 mL was cleaned to remove surface dust and contaminants. It was rinsed with distilled water, soaked in methanol and air dried. After weighing the plates, they were treated with the test solution for 8 hours, during which time the solution was constantly stirred.
The plates were then cleaned, dried and weighed. The corrosive action of the test liquid was expressed as weight loss of Al per hour and per m ² . In all tests, the liquid cleaning compositions were added to give a concentration of 10 g/cube of cleaning solution, unless otherwise specified. Corrosion vs. Water Hardness Test Example compositions were tested with a control composition (i.e., the example composition containing no silica) in water of various hardness at a temperature of 85° C. according to the corrosion test method described above. compared. Water hardness is expressed in degrees of French hardness (1 degree French hardness is 10 mg).
CaCO ₃ /stand). The following results were obtained:

Table: Corrosion vs. Temperature Test The compositions of the Examples were compared to a reference composition according to the corrosion test method described above at various temperatures using deionized water as the cleaning fluid. The following results were obtained:

[Table] These results clearly demonstrate the corrosion prevention effect of silica. EXAMPLE The following composition was made: Ingredients: % Sodium Dodecyl Benzene Sulfonate
7.0 C ₁₃ -C ₁₅ linear primary alcohol condensed with 7 moles of alkylene oxide (92:8 weight ratio mixture of ethylene oxide and propylene oxide) 2.0 Coconut Potassium Soap 1.0 Sodium Tripolyphosphate 23.8 Amorphous Silica (particle size 10nm, surface area ^700m2 /
g) 2.0 Enzyme stabilizer 7.0 Proteolytic enzyme 9GU/mg Sodium Carboxymethyl cellulose
0.1 Fluorescent brightener 0.1 Foam suppressant 0.2 Fragrance 0.3 Water Remaining PH 7.8 The compositions of the examples were subjected to corrosion tests to illustrate the corrosive effect as a function of product dosage (and thus as a function of silica concentration). Comparisons were made using deionized water as the wash solution and at a temperature of 85° C. with different product dosages and a control composition. The following results were obtained:

[Table] These results are valid if the product dosage is 120wt.
It is clearly shown that an effective corrosion prevention effect is provided when the amount is 6 g/cubic acid or more, which corresponds to ppm of silica. EXAMPLE The following composition was made: Ingredients % Sodium Dodecylbenzene Sulfonate
8.0 Sodium laolyl ether sulfate
C ₁₂ − condensed with 0.5 8 moles of ethylene oxide
2 Linear primary alcohol 2.5 Sodium pyrophosphate 11.0 Amorphous silica (particle size 10 nm, surface area 700 m ² /
g) 7.5 Enzyme stabilizer 10.0 Proteolytic enzyme 9 GU/mg Fluorescent brightener 0.2 Water Balance PH 8.0 The above composition was subjected to the same experiments as those carried out in the Examples. The investigated ranges of product dosages are different since the above products must be used in lower dosages. The following results were obtained:

TABLE The above tests indicate that at least 120 ppm and preferably 150 ppm silica should be present in the cleaning solution to provide effective corrosion protection. EXAMPLES Corrosion tests were conducted on a set of compositions made according to the formulations of the Examples, varying the type of silica used to illustrate the anti-corrosion effects of various types of silica. The amount of silica added was equal to 10% by weight of the composition. The following results were obtained at 85 DEG C., water hardness of 0 DEG and a product dosage during cleaning of 10 g/vert.

Table: Examples Compositions according to the examples were tested for their effectiveness in protecting enamel from corrosive attack. Silica specified in the examples is 2.5% by weight
It was included in an amount of Dosage during cleaning 12g/stand, water hardness of 0° and 90
The composition was subjected to an enamel application corrosion test similar to the Al-corrosion test described above. Since enamel corrosion progresses somewhat slower than metal corrosion, enamel-coated steel plates with a surface area of 100 cm ² were used and the test time was extended to 24 hours. The results showed a significant anti-corrosion effect: enamel weight loss (mg/dm ² /24 hours) 101 vs. control composition 19 vs. sample composition

Claims (1)

Claims: 1. An aqueous liquid detergent composition with improved non-corrosive properties comprising customary detergent ingredients, comprising: 200 m ² /
characterized in that silica having a surface area greater than Detergent composition. 2. A detergent composition according to claim 1, characterized in that silica is contained in an amount of about 1 to 10% by weight of the total composition. 3. A detergent composition according to any one of claims 1 to 2, characterized in that the silica has a particle size smaller than 30 nm. 4. Detergent composition according to any one of claims 1 to 3, characterized in that the silica has a surface area greater than 500 m ² /g. 5. Detergent composition according to any one of claims 1 to 4, characterized in that silica is contained in an amount of 2 to 4% by weight of the total composition. 6. A detergent composition according to any one of claims 1 to 5, characterized in that the silica has a particle size smaller than 10 nm. 7 5 to 25% by weight of anionic, nonionic,
Said silica is present in a detergent composition comprising detergent active materials of cationic and/or zwitterionic type and builder materials in an amount of from 2 to 4% by weight of the total composition. The detergent composition according to any one of claims 1 to 6, characterized in that: