EP0574431B1 - Method of cleaning carpets - Google Patents

Abstract

In this method, fitted carpets are cleaned by spray extraction using an aqueous surfactant solution containing, in addition to synthetic surfactants, 0,005 to 0,2 % by wt. of a water-soluble salt of a fatty acid with 12 to 18 C-atoms, preferably ammonium salts.

Description

The present invention relates to a method for cleaning carpets with the aid of spray extraction.

When cleaning carpets with liquid cleaning agents, a distinction is essentially made between two processes today: In the shampooing process, a relatively concentrated surfactant solution is applied to the carpet and evenly worked into the carpet material with the help of brushes or similar devices with strong foaming. After a certain exposure time, which is at least a few minutes, the foam is then suctioned off together with the dirt that has been taken up, or it is waited until the foam has dried on the carpet, in order to then suction off the solid residues. In contrast, in the spray extraction process, the cleaning agent solution is sprayed on and suctioned off in succession using the same device. For this purpose, the devices have a row of nozzles at the front in the working direction, with the aid of which the very dilute surfactant solution is blown into the textile material under high pressure, and behind it a wide suction nozzle or a series of suction nozzles with which the liquid that has just been introduced into the textile is largely expelled again the textile is removed and transferred to a storage tank of the device. A brushing device can be provided between the application nozzles and the suction nozzles. European patent application 21 799, German patent application 21 18 820 and US patent 4,219,333 describe such methods and agents which can be used in this method. Because of the relatively large amounts of liquid that are enforced in the liquid extraction process, it is necessary to use only slightly foaming or non-foaming surfactants in the cleaning solutions in order not to exhaust the capacity of the collecting container too quickly. For this reason, adducts of long-chain alcohols, ethylene oxide (EO) and propylene oxide (PO) are mainly used, which are naturally low-foaming and make the use of large amounts of defoamers unnecessary. A disadvantage of these surfactants, however, is their relatively poor biodegradability and their limited Cleaning ability. Overcoming these drawbacks was one of the objects of the present invention.

Another task arose from the desire of the commercial carpet cleaner to use as few means as possible for his cleaning operations. For the reasons outlined above, it has so far not been possible to use the same cleaning agents for both the shampooing and spray extraction processes, since on the one hand strong foaming power and on the other hand low foam requirements were required. The task here was to develop an agent that can develop large amounts of foam in the undiluted or only slightly diluted state when used in the shampooing process, but which can be handled practically foam-free in a strong dilution in the spray extraction process. Of course, the agent should have the highest possible cleaning effect in both processes.

It has now been found that these goals can be achieved using agents that contain certain soaps in certain concentrations.

The invention relates to a process for cleaning carpets by spray extraction, in which the sprayed-on cleaning liquid contains, in addition to synthetic anionic or nonionic surfactants, 0.005 to 0.2% by weight of a water-soluble salt of a fatty acid having 12 to 18 carbon atoms. The ammonium salts of the fatty acids are preferably used as water-soluble salts.

The soap content in the cleaning liquid of the process according to the invention has the effect that even when strongly foaming anionic surfactants are used, the foaming is reduced to such an extent that the existing collecting tanks for the solutions to be extracted can be optimally used. Due to the extensive freedom in the choice of synthetic surfactants, it is possible to fall back on those surfactants that are characterized by particularly high cleaning power and low tendency to re-soiling. While the cleaning liquid is extremely low-foaming at the concentration used in the spray extraction process, a corresponding liquid concentrate from which this cleaning liquid is used shows can be produced in normal operation, with undiluted use and application of brushes a strong foam development. The liquid concentrate can therefore be used undiluted or with a low dilution without further ado for the shampooing process, so that there are advantages in warehousing, above all for commercial users.

The cleaning method according to the invention can easily be carried out with the aid of conventional spray extraction devices. The work processes differ from the conventional method only in so far as the agents to be used according to the invention are used. Due to the low foam content of the agents, the addition of silicone defoamers can generally be dispensed with.

The synthetic surfactants used in the cleaning liquid are nonionic and, preferably, anionic surfactants, although the use of other types of surfactants may also be appropriate in individual cases. The content of synthetic anionic and / or nonionic surfactants in the cleaning solution is preferably between 0.005 and 0.2% by weight, in particular between 0.04 and 0.08% by weight. The cleaning solution is preferably produced predominantly or exclusively with those surfactants which, together with the other constituents of the cleaning solution, lead to solid, brittle residues after the liquor remaining on the carpets has dried on.

Suitable anionic surfactants are in particular those of the sulfate or sulfonate type, but other types such as long-chain N-acyl sarcosinates, salts of fatty acid cyanamides or salts of ether carboxylic acids, as are obtainable from long-chain alkyl or alkylphenyl polyglycol ethers and chloroacetic acid, can also be used. The anionic surfactants are preferably used in the form of the sodium salts.

Particularly suitable surfactants of the sulfate type are the sulfuric acid monoesters of long-chain primary alcohols of natural and synthetic origin with 10 to 20 carbon atoms, ie of fatty alcohols, such as, for. B. coconut fatty alcohols, tallow fatty alcohols, oleyl alcohol, or the C₁₀ - C₂₀ oxo alcohols and those of secondary alcohols of these chain lengths. she The sulfuric acid monoesters of the aliphatic primary alcohols, secondary alcohols or alkylphenols (ether sulfates) ethoxylated with 1 to 6 moles of ethylene oxide are also suitable. Sulfated fatty acid alkanolamides and sulfated fatty acid monoglycerides are also suitable.

The surfactants of sulfonate type are primarily sulfosuccinic acid monoesters and diesters with 6 to 22 carbon atoms in the alcohol parts, the alkylbenzenesulfonates with C₉ - C₁₅ alkyl groups and the esters of α-sulfofatty acids, e.g. B. the α-sulfonated methyl or ethyl esters of hydrogenated coconut, palm kernel or tallow fatty acids. Other useful surfactants of the sulfonate type are the alkanesulfonates which are obtainable from C₁₂-C₁₈ alkanes by sulfochlorination or sulfoxidation and subsequent hydrolysis or neutralization or by bisulfite addition to olefins, and also the olefinsulfonates, which are mixtures of alkene and hydroxyalkanesulfonates and disulfonates, such as they are obtained, for example, from long-chain monoolefins with a terminal or internal double bond by sulfonation with gaseous sulfur trioxide and subsequent alkaline or acidic hydrolysis of the sulfonation products.

Preferred are the alkyl sulfates with 12 to 18 carbon atoms, the salts of sulfosuccinic acid monoesters with 15 to 20 carbon atoms in the alcohol part, the alkylbenzenesulfonates with 10 to 13 carbon atoms in the alkyl chain, the sulfates of the fatty alcohols ethoxylated with 1 to 3 mol EO with 12 - 18 carbon atoms and mixtures of these surfactants. Of these, the fatty alcohol sulfates with 12 to 18 carbon atoms are particularly preferred.

Suitable nonionic surfactants for the process according to the invention are, in particular, addition products of 1 to 30, preferably 3 to 15, moles of ethylene oxide with 1 mole of a long-chain compound having 10 to 20 carbon atoms from the group of alcohols, alkylphenols, carboxylic acids and carboxamides. The addition products of ethylene oxide (EO) with long-chain primary or secondary alcohols, such as, for example, fatty alcohols or oxo alcohols, and with mono- or dialkylphenols with 6 to 14 C atoms in the alkyl groups are particularly important. However, other nonionic surfactants can also be used, for example long-chain amine oxides and Alkyl glycosides. Particularly preferred nonionic surfactants are fatty alcohols or oxo alcohols with 10 to 20 carbon atoms, which are ethoxylated with 3 to 10 mol of EO, and mixtures of compounds of this type with different degrees of ethoxylation.

As a further constituent essential to the invention, the cleaning liquid used contains a water-soluble salt of a fatty acid with 12 to 18 carbon atoms. The alkali soaps of this chain length can be used, i. H. the lithium, sodium and potassium salts of the fatty acids, but also the salts of fatty acids with ammonia or suitable amines, for example triethanolamine. The ammonium soaps accessible from fatty acids and ammonia are particularly preferred. The content of fatty acid salts in the cleaning liquid is usually 0.005 to 0.2% by weight, preferably 0.03 to 0.06% by weight. The ratio of soap to other surfactants in the cleaning liquids is preferably between 0.2: 1 and 3: 1, in particular between 0.5: 1 and 2: 1.

The cleaning liquid can be used for the process according to the invention without further additives. In many cases, however, it can be expedient to add further auxiliaries customary in carpet cleaning agents to the cleaning solution. Particularly noteworthy are sequestering agents, anti-pollution agents, antistatic agents, hydrotropes, organic solvents, preservatives and perfume. When selecting the auxiliary materials, especially those that are contained in large quantities in the cleaning agent, preference is also given to those which lead to solid residues on the carpet after the liquid residues have dried off, since these can later also be vacuumed dry.

The auxiliaries which are intended to reduce the re-soiling of the carpet are primarily water-soluble or water-dispersible polymers which have film-forming temperatures above 70 ° C. and do not lead to films after drying, but to brittle residues. Corresponding polyacrylates and polymethacrylates are preferably used. Their concentration in the cleaning liquid is normally not more than 0.5% by weight, preferably between 0.01 and 0.3% by weight.

Quaternary ammonium compounds which attach to the textile material are usually used as active ingredients which are intended to provide the carpet with a certain antistatic finish. Inorganic salts can also have an antistatic effect on the carpet. The total content of auxiliaries in the cleaning agent solution, calculated without organic solvents, is generally not more than 1% by weight, preferably between 0.01 and 0.5% by weight.

The cleaning liquids sprayed in the cleaning process according to the invention can be mixed directly from the components. However, since these are very dilute cleaning agent solutions, it had been established in practice to prepare these solutions before use from more concentrated preparations, which contain the active ingredients in appropriate proportions in higher concentrations, by dilution with water. The concentrates can be solid, powdery products; However, more common are concentrates in liquid form, which contain all active ingredients. For the production of stable liquid concentrates, it may be necessary to add solubilizers that ensure the perfect miscibility of all ingredients. Suitable solubilizing additives are primarily hydrotropes, for example the salts of short-chain alkylbenzenesulfonic acids or low-boiling, water-miscible organic solvents, for example ethanol and isopropanol. The concentration of the active compounds in the concentrates is generally chosen so that the desired use concentrations can be achieved by dilution with Nasser in a ratio of from 1:30 to 1: 300, preferably from 1:50 to 1: 100.

Examples 1. Detergent concentrates

The following agents (Table 1) were prepared by dissolving the active ingredients in water and, if appropriate, organic solvent. The content is given in percent by weight, in each case calculated as a pure active substance. Table 1 concentrate a b c d e Sodium Lauryl Sulfate (Texapon ^(R) K 12) 3.8 3.8 - 5.0 - Sodium lauryl ether sulfate (2EO) (Texapon ^(R) N 25) - - 4.0 - - C _10/12 fatty alcohol + 6 PO + 4 EO - - - - 8.0 Polymethyl methacrylate (Ubatol ^(R) TR 1138) 6.4 6.4 6.4 10.0 - NH₄ soap from coconut palm kernel fatty acid ⁽ Edenor ^(R) KPK) 2.8 - 2.5 - - K-Soap from Coconut Palm Kernel Fatty Acid ⁽ Edenor ^(R) KPK) - - - 3.5 - Sodium cumene sulfonate - - - - 3.0 Nitrilotriacetic acid tri-Na salt - - - - 1.5 Ethanol 7.5 7.5 7.5 7.5 - Butyl glycol - - - - 1.0 Perfume + + + + + Preservative - - - - + Water ad 100%

2. Cleaning procedure

The agents according to Example 1 (a - e) were compared both with regard to their cleaning power and their foaming behavior in the spray extraction process and also checked for their usability in the shampooing process.
a) Checking the cleaning effect
Uniform, naturally soiled carpets (polyamide velor, beige) were cut into test specimens measuring 33 cm x 79 cm, only test specimens with the same degree of soiling being used for the test. The products (a, c, d) used according to the invention, as well as a comparison product (b) and a commercially available product (e) were diluted 1: 100 with tap water to the application concentration.
With a spray extraction device (Kärcher Puzzi S), each piece of carpet was sprayed and vacuumed evenly from all sides. The cleaning speed was chosen so that the product consumption per test specimen was 700 ml (± 50 ml). In the last step, the carpet samples were sucked off (against the pile direction without spraying) so that the carpet fiber was set up to dry.
After a drying phase of at least 12 hours, the test specimens were suctioned off from each side in a cross-way with a brush suction device (Siemens Universal Plus). Finally, the fibers of the carpet specimens were all brushed in the same direction using a soft brush.
The individual pieces of carpet were assessed visually in comparison to one another and to an uncleaned pattern. The assessment was carried out by 5 examiners who assessed each piece individually on a scale from 1 (completely clean) to 5 (no cleaning recognizable). Table 2 contains the results in the form of the mean values from 3 individual experiments.
b) Procedure for determining the suction quantity (without defoamer additive)
The fresh water tank was filled with 7.00 kg of the detergent solution to be tested (dilution of the concentrates 1: 100 with tap water) in a commercially available spray extraction device (Kärcher Puzzi S). The product to be tested was transferred to the dirty water tank by spraying the product onto a hard, clean plastic floor and simultaneously vacuuming it off. When the dirty water tank had reached its maximum filling quantity, the total weight of the extracted quantity was determined. Ideally (no foam formation), the amount of solution used could be sucked up without changing the dirty water tank. From the results in Table 2 it can be seen that in this respect the agents used according to the invention are superior to the commercially available product, while this in turn is to be rated better than the comparison product without added soap.
c) Testing as a shampoo
The test is carried out on polyamide velor carpets. 500 g of agents 1 a - e diluted with water in a ratio of 1: 4 (concentrate: water) were applied per m² using a shampooing machine (Shampooner Hoover F 4002) and brushed in. Only in cases 1a - d did enough foam develop for even distribution and gentle brushing. Table 2 Recipe 1a 1b 1c 1d 1e Cleaning performance 1.8 2.0 2.1 1.6 2.0 Suction volume (kg) 7.00 4.40 7.00 7.00 5.30 suitable for spray cleaning Yes conditionally Yes Yes Yes suitable for shampoo cleaning Yes Yes Yes Yes No

Claims (7)

1. A process for cleaning carpets by spray extraction, characterized in that the cleaning liquid sprayed on contains 0.005 to 0.2% by weight of a water-soluble salt of a C₁₂₋₁₈ fatty acid in addition to synthetic anionic and/or nonionic surfactant.
2. A process as claimed in claim 1 using a cleaning liquid in which an ammonium salt is used as the fatty acid salt.
3. A process as claimed in claim 1 or 2 using a cleaning liquid in which the ratio of fatty acid salts to synthetic surfactants is between 0.2:1 and 3:1 and, more particularly, between 0.5:1 and 2:1.
4. A process as claimed in claim 1 or 2 using a cleaning liquid containing an anionic surfactant as the synthetic surfactant.
5. A process as claimed in claim 4 using a cleaning liquid containing an alkyl sulfate as the anionic surfactant.
6. A process as claimed in 1 or 2 using a cleaning liquid additionally containing a water soluble polymer having a film forming temperature above 70°C, preferably a polymethacrylate.
7. A process as claimed in any of claims 1 to 6, in which the cleaning liquid is prepared by diluting a cleaning concentrate of suitable composition with water in a ratio of 1:30 to 1:300 and preferably 1:50 to 1:100.