DE69602355T2 - METHOD AND COMPOSITION FOR CLEANING SURFACES - Google Patents

Description

Field of the invention

The present invention relates to a method and a composition for cleaning surfaces.

History of the invention

It is known to apply cleaning compositions containing surfactants to surfaces by spraying droplets of the composition onto a surface. In known spraying methods, the film of the composition is deposited continuously on the surface over a large part of the area, although a discontinuous field of droplets may be observed towards the edges of the spray pattern. This type of application enables the product to be targeted to the area of the surface where it is needed. The spraying apparatus, such as so-called "trigger pumps", used to deliver cleaning compositions usually delivers large doses of product in the form of relatively large droplets which flow and coalesce on the surfaces so as to form a continuous film of the composition.

It is also known to apply foams, which are not homogeneous on a small scale by definition, to a surface spray. Again, the trigger pumps used to deliver compositions in this form are known to deliver relatively large quantities of product.

Brief description of the invention

It has been found that when products containing aqueous solutions of non-ionic surfactants or non-ionic surfactant/solvent systems are sprayed as fine droplets to form a discontinuous film, either less cleaning power can be used with the same level of product, or the same effort can be used with less product. It is believed that the effect is due to the presence of an increased number of menisci and the evaporation of the aqueous liquid or part of any solvent component from the product to the surface. It is further believed that this evaporation, particularly at menisci, causes local increases in concentration and/or local turbulence which enhances the cleaning process. It has been found that a similar effect can also be observed with foams.

Detailed description of the invention

Accordingly, a first object of the invention provides a packaged aqueous or solvent-containing non-ionic cleaning composition in a container provided with a spray nozzle adapted to deliver the composition to a surface in the form of a spray, characterized in that the dosage applied to the surface on each actuation of the spray apparatus falls within the range of 0.15 to 0.5 ml, and said dosage is applied over an area of at least 50 cm² when the spray nozzle is actuated 15 cm from the surface.

A second subject matter of the invention relates to a method for cleaning a hard surface, which comprises the step spraying a composition containing a non-ionic surfactant from a container provided with a spray nozzle onto a surface in the form of a spray jet, characterized in that the dosage applied to the surface during each operation of the spraying apparatus falls within the range 0.15 to 0.5 ml, and said dosage is applied over an area of at least 50 cm² when the spray nozzle is in operation 15 cm from the surface.

As mentioned above, it is believed that by spreading the product on the surface in the form of discrete droplets and/or a foam which does not form a continuous film, a meniscus cleaning effect is promoted which aids the cleaning process. It is an important feature of the present invention that coalescence of the product on the surface to form a continuous film should be reduced, although it will be appreciated that some coalescence may occur.

Typically, the dosage applied to the surface with each actuation of the sprayer falls within the range of 0.2 to 0.4 ml: dosages of 0.25 to 0.35 ml are particularly preferred. Previously used spray jets for hard surface cleaners typically deliver upwards of 0.7 ml per spray, i.e. larger dosages than the spray jets of the present invention. It is particularly preferred in the process of the invention that the dosage is equivalent to at least 0.3 ml of product delivered over an area of 80 cm².

The preferred spray cone angles are such that 0.15 to 0.5 ml of product is recovered over a circular area of at least 10 cm diameter. The preferred droplet pattern on the surface is such that for each pump cycle a calculated 10 to 40 ml of product is recovered over each square meter of surface.

Typical cone angles in the embodiments of the present invention are 25 to 75 degrees. Previously used spray jets for hard surface cleaners often provide the product in a relatively narrow angle or jet, as well as delivering significantly larger amounts of product per pumping cycle. As particularly mentioned above, an important feature of the present invention is the reduced dosage and/or increased area of effect as compared to the prior art.

The preferred droplet size distribution is such that, for a 10 g amount, less than 350 mg of product is present in droplets having a particle size of less than 7 microns. Preferably, less than 700 mg of product is present in droplets having a particle size of less than 30 microns.

Typically the mean particle size will be in the range of 50 to 100 microns. It is believed that this avoids the problem of respirable particles while ensuring that the product is delivered to the surface rather than remaining suspended in air. It is also believed that using this range of distribution provides good surface coverage and promotes the meniscus cleaning effect mentioned above.

The droplet size range for a typical product now on the market (“CIF multiuso” (TM) trigger pack) appears to be 30 to 700 microns, with a peak at about 250 microns.

The composition must have a viscosity such that it can be obtained in the form of a spray. It is also considered essential that the composition contains at least one non-ionic surfactant. The compositions according to the present invention may be a simple solution or in a more complex form, such as a microemulsion.

Particularly preferred compositions contain from 2 to 30% nonionic surfactant, more preferably from 3 to 13% nonionic surfactant. Anionic surfactant is optional. Preferred nonionic surfactants include alkoxylated alcohols, particularly ethoxylated C₈₋₁₈ alcohols with from 3 to 8 moles of ethylene oxide per mole of alcohol. Other nonionic surfactants may be used, a variety of the surfactants mentioned being described in "Nonionic Surfactants" by Schick (Arnold: Surfactant Science Series, Volume 1).

The preferred concentrations of surfactant fall within the range of 5 to 15 weight percent total surfactant, with levels of about 10 weight percent product being preferred. These concentrations are higher than those typically used for atomizing compositions, however, due to the lower dosage of the composition and the improved cleaning effectiveness observed with the conventional methods of the present invention, it is possible to reduce the overall use of surfactant. Not only does this have a direct environmental consequence, but there is also an indirect benefit in that less packaging is used for the smaller containers in which the product may be packaged and less fuel is consumed in transporting the product. There is also an immediate benefit to the consumer that effective cleaning can be obtained with a lightweight, yet effective, delivery device.

Hydrophobic oils are optional components of the compositions according to the present invention. Suitable oils include oils which rapidly dissolve triglyceride. When oils are present, preferred oils include limonene, p-cymene, dibutyl ether and butyl butyrate.

Solvents are preferably present in amounts of 3 to 20% by weight, with amounts of 5 to 10% by weight being particularly preferred. Glycol ethers and/or lower alcohols having 1 to 5 carbon atoms are preferred as solvents, although the use of short-chain alkyl esters including ethyl acetate and/or pyrrolidones including N-methylpyrrolidone is also conceivable. Preferably, the solvent is selected from: propylene glycol mono-n-butyl ether, dipropylene glycol mono-n-butyl ether, propylene glycol mono-tert-butyl ether, dipropylene glycol mono-tert- butyl ether, diethylene glycol hexyl ether, methanol, ethanol, isopropyl alcohol, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether and mixtures thereof.

Particularly preferred solvents are selected from the group comprising ethanol (preferably as industrially methylated spirits), propylene glycol mono-n-butyl ether (available as "Dowanol PnB" [RTM]), and diethylene glycol monobutyl ether (available as "Butyl Digol" [RTM] or "Butyl Carbitol" [RTM]). These solvents are preferred due to cost, availability, and safety factors. This selection of solvents has been found to provide enhanced cleaning performance with respect to inks and dyes.

While the compositions of the present invention may also be alkaline, acidic or neutral, it is preferred that the compositions be fairly strongly alkaline with a preferred pH of > 10.

It is particularly preferred that the composition contains 1 to 10% of an alkanolamine, with contents of 2 to 6% by weight being particularly preferred.

Particularly suitable alkanolamines include: 2-amino-2- methyl-1-propanol, monoethanolamine and diethanolamine. These materials are believed to provide improved cleaning on tough or aged soils.

We have determined that it is particularly advantageous to include in the compositions of the present invention a polymer so as to reduce the level of formation of exceptionally fine droplets, i.e. droplets which may be inhaled and cause irritation to the consumer. Suitable polymers include PVP, available on the market as polymer PVP K-90.

Suitable contents of PVP polymers are in the range of 50 ppm and above. Contents of 500 to 1500 ppm are particularly preferred.

The composition preferably has a pH of > 10 and comprises, in admixture with water:

(a) 3 to 13% non-ionic surfactant

(b) 0 to 10% solvent

(c) 2 to 6% alkanolamine

(d) 0 to 5% buffer/alkali, and

(e) 50 to 1500 ppm polymer.

Particularly preferred compositions have a pH of > 10 and comprise, in admixture with water:

(a) 3 to 13% non-ionic surfactant (particularly preferably C10-EO5 non-ionic surfactant)

(b) 5 to 10% solvent (particularly preferred is diethylene glycol mono-n-butyl ether)

(c) 2 to 6% alkanolamine (particularly preferred 2-amino- 2-methyl-1-propanol)

(d) 1 to 5% buffer/alkali (preferably sodium or potassium carbonate), and

(e) 500 to 1000 ppm polymer (preferably PVP), wherein said composition is packaged in a container adapted to produce a spray of 0.15 to 0.5 ml of product per spraying, said spray having an average droplet size in the range of 30 to 300 microns.

In order that the present invention may be better understood, it will be described below with reference to examples and with reference to the single accompanying figure.

Examples

The cleaning performance was determined on soiled DECAMEL (RTM, from Formica) sheets. 0.5 mg/cm² (based on non-volatile compounds) of soil was deposited by spraying on an "A4" sized area of a "DECAMEL" test surface. The soil contained 1% glycerol tripalmitate, 0.5% glycerol trioleate, 0.5% kaolin, 0.2% liquid paraffin, 0.1% palmitic acid, 0.02% soot in methylated spirits. The dirt was aged for 24 hours at room temperature before cleaning.

The force used to remove the dirt from the test surface using a cellulose gauze cloth was measured.

example 1

Compositions were prepared by mixing the components listed in Table I below.

Table I

10% Imbentin 91-35 (TM) C10-EO5 non-ionic surfactant

8% Butyl Digol (TM): Diethylene glycol mono-n-butyl ether

4% 2-amino-2-methyl-1-propanol

2% buffer/alkali (sodium carbonate)

up to 100% water

From Table I it can be seen that the composition is a concentrate (as far as surfactant is concerned) as compared to conventional spray cleaning compositions which contain approximately 4% by weight surfactant, 5% solvent.

Table II and Figure 1 show results for six sprays using the composition described above. The compositions were sprayed onto undried soiled DECAMEL bricks prepared as described above using a variety of pumps. The These pumps are identified in Table II as P1-P3 and C1-C3. The P series pumps were obtained from "Perfect Valois" (TM) and the C series pumps from "CALMAR" (TM). The P series pumps are identified by the manufacturing codes as follows: P1: PZ2/290 4627, P2: PZ2/290 3020, P3: PZ2/290 2502. The C series pumps are identified by the manufacturing codes as follows: C1: M300 HV, C2: M300 60 degree discharge opening, C3: M300 30 degree discharge opening.

In the table and figure, "DS" (droplet size) is the mean particle concentration, averaged over a period of five minutes from spraying, in air, of particles per cm3 of diameter smaller than 7 microns. Higher numbers for the "DS" (droplet size) correspond to lower average droplet diameters in the spray liquid.

More detailed data were obtained for pumps P1-P3 and are given in Table III below. From these data it can be seen that there is a relationship between the droplet size "DS" as measured above and the mean particle size produced by the atomizations. Table III Particle diameter in microns

Returning to Table II, the cone diameter is as measured at 15 cm, ie it is the diameter of the atomizing pattern at 15 cm from the atomizer head.

The dose is the dose applied to the bricks over the area sprayed with product. In all cases, more than one cycle of the atomizer was used.

The power is the total power required to completely clean a brick, measured by the total power applied by a human operator in Ns. Table II

From the figures given in Table II it is possible to calculate the dose per unit area and thus the cleaning efficiency in terms of the required output per dose of product per unit area sprayed. Figure 1 plots this efficiency against the two series of "Drop Size" (DS) measurements expressed in terms of the quantity of fine droplets. From the figure it is clear that the efficiency is higher for higher values of "DS", ie the same Amount of product distributed in finer droplets allows to clean the surface with less effort. This applies to both the "P" atomizing series and the "C" atomizing series.

Example 2

To demonstrate the effect of a polymer on droplet size distribution, tests were carried out with a Calmar (TM) M300 6/35/BB034 pump operated as a finger pump from the rear. These tests showed that in the absence of polymer, the mean particle concentration, averaged over a five minute period from spraying, in air, of particles per cubic centimeter of diameter less than 7 microns was 315, but that in the presence of 500 ppm PVP (Polymer PVP K-90) the mean particle concentration dropped to 79.

Table IV below provides additional data for a tub in which the finger pump (all available from Calmar) was operated by a lever. Table IV

It can be seen from Table IV that the use of a lever and expansion thereafter further reduces the content of respirable droplets produced.

Example 3

In order to demonstrate directly the effect of varying the manner in which the product is dosed, compositions were prepared by mixing the components given in Table V below.

Table V

10% Nonidet 91-6T (TM) C10-EO6 non-ionic surfactant

8% Butyl Digol (TM): Diethylene glycol mono-n-butyl ether

4% 2-amino-2-methyl-1-propanol

1.25% buffer/alkali (potassium carbonate)

1000 ppm PVP-K90

0.2% perfume

up to 100% water

These compositions were applied to soiled DECAMEL bricks in three ways, by conventional atomizing spray, by pipette and at low dosage according to the invention. Table VI below gives details of dosage (ml), power required for cleaning (Ns) and cleaning effectiveness (10/- [ln(power) X dose]). Efficacy was defined without reference to spray range in this case. Table VI

From the results of Table VI it can be seen that the use of the product in the low dosage capacity of the invention provides more effective cleaning than any higher dosage of the conventional trigger pack which would show some discontinuity of distribution or the particularly high dose pipette from which the product was distributed as a puddle. It should be noted that in these experiments the same composition was used in each case to eliminate the possibility that the concentration of the product was influencing the results.

Claims (8)

1. A packaged aqueous or solvent-based cleaning composition containing a nonionic surfactant in a container provided with a spray nozzle adapted to deliver the composition to a surface in the form of a spray, characterized in that the dosage applied to the surface on each actuation of the spray apparatus falls in the range 0.15 to 0.5 ml, and said dosage is applied over an area of at least 50 cm² when the spray nozzle is actuated 15 cm from the surface. 2. A method for cleaning a hard surface, comprising the step of spraying a composition containing a non-ionic surfactant from a container provided with a spray nozzle onto a surface in the form of a spray, characterized in that the dosage applied to the surface on each actuation of the spray apparatus falls within the range of 0.15 to 0.5 ml, and said dosage is applied over an area of at least 50 cm² when the spray nozzle is actuated 15 cm from the surface. 3. A process according to claim 2, wherein the droplet size distribution of product in the spray is such that for a 10 g output less than 350 mg of product is present in droplets having a particle size of less than 7 microns. 4. A process according to claim 2, wherein the composition contains 1 to 10% of an alkanolamine. 5. A method according to claim 2, wherein the composition contains a polymer. 6. A method according to claim 2, wherein the composition has a pH of > 10. 7. A method according to claim 2, wherein the composition has a pH of > 10 and contains in admixture with water: (a) 3 to 13% non-ionic surfactant (b) 0 to 10% solvent (c) 2 to 6% alkanolamine (d) 0 to 5% buffer/alkali, and (e) 50 to 1500 ppm polymer. 8. A method according to claim 2, wherein the composition has a pH of > 10 and contains in admixture with water: (a) 3 to 13% non-ionic surfactant (b) 5 to 10% of a glycol ether solvent (c) 2 to 6% alkanolamine (d) 1 to 5% sodium or potassium carbonate, and, (e) 500 to 1000 ppm of polymer (preferably PVP), wherein said composition is packaged in a container adapted to produce a spray of 0.15 to 0.5 ml of product per spraying operation, said spray having an average droplet size in the range of 30 to 300 microns.