GB2027736A

GB2027736A - Cleaning Preparation for Glass Surfaces

Info

Publication number: GB2027736A
Application number: GB7927769A
Authority: GB
Original assignee: Smiths Group PLC
Current assignee: Smiths Group PLC
Priority date: 1978-08-11
Filing date: 1979-08-09
Publication date: 1980-02-27

Abstract

A cleaning preparation for use in cleaning vehicle windscreens, headlamp glasses and the like comprises an aqueous solution containing a cleaning agent, preferably volatile, such as a mildly- alkaline mixture of ammonia solution and phenol, and a water-soluble cellulose derivative, such as sodium carboxymethyl-cellulose. In use the preparation is added to, for example, reservoir water of a vehicle windscreen-washing system and the resulting solution applied to a windscreen in the normal manner to clean the windscreen. The preparation may also include a wetting agent and a freezing-point depressant, for example, isopropylalcohol.

Description

SPECIFICATION Cleaning Preparations This invention relates to cleaning preparations and is concerned especially with cleaning preparations for cleaning vehicle windscreens and other transparent panels such as, for example, headlamp glasses.

The invention is particularly concerned with cleaning preparations which are to be added to water contained in, for example, a reservoir of a vehicle windscreen and/or headlamp glass washing system.

Heretofore, various additives have been proposed which may be added to water contained in the reservoir of a vehicle windscreen washing system in order to effect more efficient cleaning of the windscreen, and in particular the removal of oil-bound dirt particles from the windscreen.

These known additives generally comprise an aqueous solution which contains a cleaning agent such as, for example, sodium hydrogen phosphates and a detergent, thio-acids, or washing soda and soaps. Whilst these additives, when dissolved in the water of a windscreen washing system and sprayed onto a windscreen, have generally proved satisfactory in their ability, together with the operation of windscreen wipers, to remove dirt particles from the windscreen, it has been found that they tend to cause smearing on the windscreen. It is believed that this smearing results from the use of the abovementioned cleaning agents and that upon evaporation of the aqueous solution from the windscreen, a small amount of opaque precipitation from the cleaning agents is left behind on the windscreen.For example, when an additive including sodium hydrogen phosphates is mixed with hard tap water contained in a windscreen washer reservoir, an unsoluble precipitate of calcium phosphates is formed in the solution which is subsequently sprayed onto the windscreen. This precipitate remains on the windscreen when the remainder of the solution has evaporated and gives rise to smearing.

It is an object of the present invention to provide a cleaning preparation suitable for use as an additive in a washing system which is capable of readily removing oil-bound dirt particles from vehicle windscreen, headlamp glasses or other transparent panels.

Another object of the present invention is to provide a cleaning preparation, suitable for use as an additive for a windscreen and/or headlamp glass washing system, having a cleaning agent which substantially overcomes the above disadvantage.

According to one aspect of the present invention, a cleaning preparation for use in cleaning vehicle windscreens and the like comprises an aqueous solution which contains a cleaning agent and a water-soluble cellulose derivative.

The water-soluble cellulose derivative preferably comprises sodium carboxymethylcellulose. The sodium carboxymethylcellulose may comprise 0.2 to 10% by weight per total volume of the aqueous solution.

The cleaning agent is preferably volatile and may comprise 0.2 to 8% by weight per total volume of the aqueous solution. The cleaning agent may be a mixture of ammonia and phenol, the ratio of ammonia to phenol being such that the cleaning agent is mildly alkaline.

The aqueous solution may also include a wetting agent and a freezing-point depressant, for example, isopropylalcohol.

According to another aspect of the present invention a washing solution for washing vehicle windscreens and the like comprises a mixture of a cleaning preparation in accordance with the one aspect of the present invention, and water, wherein the cleaning preparation comprises 1 to 20% by volume of the washing solution.

Cleaning preparation in accordance with the present invention and in particular preparations for use as additives in vehicle windscreen washing systems will now be described by way of example.

The cleaning preparations to be described are intended to be added to water contained in a reservoir of a vehicle windscreen washing system to assist in the removal of dirt particles and such like from the windscreen.

The cleaning preparations generally comprise an aqueous solution containing a cleaning agent.

The aqueous solution includes a chemical which has the effect of improving the 'wetting' properties of the water in the reservoir to which the cleaning preparation is added. The mixture comprising the preparation and the reservoir water, hereinafter referred to as the washing solution, spreads more easily over the surface of the windscreen and is able to cover a larger area.

An example of such a wetting agent is isopropylalcohol which improves the wetting properties of the washing solution possibly by reducing the surface tension of the reservoir water. This particular chemical has an added advantage in that it is capable of lowering the temperature at which the preparation freezes.

Subject to seasonal requirements, a sufficient quantity of this chemical may be included in the cleaning preparation such that, when the preparation is added in predetermined proportions to the water in the reservoir of the windscreen washing system, the resulting solution, that is, the washing solution, is prevented from freezing at the lowest temperature expected to be encountered.

The use of isopropylalcohol is particularly convenient since it serves as both a wetting agent and a freezing-point depressant. However, other known wetting agents and other known freezingpoint depressants may be employed instead.

The cleaning agent comprises a mixture of an ammomia solution, for example, I.C.l's Ammonia Liquor, and phenol. The phenol is preferably provided in the form of detached phenol crystals which are convenient to handle during manufacture of the cleaning preparation and are also easily dissolved in the aqueous solution. Both the ammonia solution and the phenol are volatile and evaporate completely from the windscreen to which they are applied in contrast to cleaning agents such as washing soda and soaps, or thioglycollic acid which tend to leave precipitates on the windscreen.

In addition to the cleaning agents, a watersoluble cellulose derivative having a refractive index, when in the form of a thin film, substantially the same as that of the glass of the vehicle windscreen, is also added to the aqueous solution of the cleaning preparation for reasons which will become apparent. One example of such a water-soluble cellulose derivative is sodium carboxymethylcellulose which is commercially available under the name 'cellulose gum' from the Hercules Powder Company Limited.

Sodium carboxymethylcellulose dissolves rapidly in hot or cold water, is oil resistant, and has the ability to thicken the solution to which it is added. Thus by including such a cellulose derivative in the cleaning preparation, the preparation is thickened and packaging of the preparation in, for example, sachets, and transfer of the preparation from its package to the reservoir of the windscreen washing system is greatly facilitated.

With the exception of the cellulose derivative, each of the ingredients of the cleaning preparation is volatile. Hence, when the cleaning solution containing the cleaning preparation is sprayed onto a vehicle windscreen, all the ingredients, apart from the cellulose derivative (and perhaps minute traces of solids that may unavoidably be present in ordinary tap water), either evaporate from the windscreen or are wiped away, together possibly with some of the cellulose derivative, by the wiper blades if operated. The cellulose derivative that is left behind on the windscreen forms a thin film on the area of the windscreen over which the cleaning solution spreads or is wiped.This thin layer is transparent and, in the case of sodium carboxymethylcellulose in particular, has a refractive index of approximately 1.5, which is substantially the same as that of the glass of a vehicle windscreen, so that optical transmission through the vehicle's windscreen is substantially unaffected.

It has been found that the thin film formed by the cellulose derivative in the above manner will fill minute scratches on the surface of the windscreen, such as those caused by, for example, dirt particles trapped between the wiper blades and the windscreen. In the case of wider and deeper scratches, the thin film of cellulose derivative only partially fills the scratches but, in doing so, provides a smoothly-contoured covering over the sharp, prismatic edges of the scratches.

Scratches on the surface of the windscreen tend to scatter light and are a common source of glare.

Thus, by filling in these minute scratches, or at least providing a smoothly-contoured layer over sharp edges of larger scratches, the thin film of cellulose derivative helps to eliminate this source of glare.

As previously mentioned, cellulose derivatives, such as sodium carboxymethylcellulose, are oil resistant. This property has a particular advantage with regard to the thin film of cellulose derivative formed on the vehicle's windscreen. The thin film provides a protective barrier on the surface of the windscreen and any oil or diesel-fuel coated particles of dirt which may be thrown up from the road surface or emitted from vehicle exhausts, and indeed other dirt particles, adhere to this thin film and are prevented from directly contacting the area of the windscreen behind the thin film.

Upon the next application of cleaning solution to the windscreen, the thin film, together with the adhering particles of dirt, are dissolved and washed away from the windscreen, possibly with the help of the vehicle's windscreen wipers, and a fresh film of cellulose derivative is formed on the windscreen. It is seen therefore that the inclusion of the cellulose derivative in the cleaning preparation provides a simple and effective means of preventing dirt particles adhering directiy to the windscreen and at the same time enables dirt particles and such like to be easily removed from the windscreen.

One particular example of a cleaning preparation in accordance with the present invention will now be described. The aqueous solution includes a mixture which comprises approximately 80% by volume of water and 20% by volume of isopropylalcohol. To this mixture is added approximately 1% by weight per total volume of sodium carboxymethylcellulose and approximately 0.75% by weight per total volume of each of the cleaning agent constituents, which comprise I.C.l's ammonia liquor having a specific gravity of approximately 0.88, and detached phenol crystals. The ammonia liquor, which is alkaline, and the phenol crystals, which is acid, are mixed in predetermined proportions such that the cleaning agent has a pH value in the order of 9, that is, the cleaning agent is mildly alkaline.

The chemical environment of the cleaning preparation helps to prevent the cleaning preparation from gelling during prolonged periods of storage of the cleaning preparation in its packaging. Furthermore, the presence of ammonia liquor and phenol in the preparation helps to eliminate bacteria or fungi which may otherwise feed on the cellulose derivative.

The specific example of the cleaning preparation described above is illustrative of a preferred cleaning preparation particularly suitable for use as an additive for water contained in a windscreen washer reservoir and improves considerably the cleaning power of the windscreen washing system.

It is envisaged however that the relative proportions of the ingredients constituting the cleaning preparation may be varied to suit different requirements. For example, the proportion of cleaning agent in the cleaning preparation may be increased to cope with more difficult dirt and grime which may be encountered in some situations. In general, the cleaning agent comprises between 0.2% and 8% by weight per total volume of the cleaning preparation.

Similarly, the amount of sodium carboxymethylcellulose can also be varied, preferably lying within the range of 0.2 to 10% by weight per total volume of the cleaning preparation.

As previously mentioned, the cleaning preparation is conveniently packaged in sachets.

Each sachet preferably contains approximately 33 ml of the cleaning preparation and this amount has been found to be sufficient to treat approximately one litre of water. Generally speaking however, the preparation may be added to the water such that the resulting washing solution contains 1 to 20% by volume of the cleaning preparation.

Additional quantities of isopropyl alcohol or other totally insoluble freezing point depressant may be added to suit seasonal requirements.

Of course, the cleaning preparation can also be used in a headlamp glass washing system.

Although the cleaning preparation is particularly suitable for use in cleaning transparent surfaces, such as glass, in vehicles, it may also be used to clean other surfaces such as mirrors and windows of buildings. In this case, the cleaning preparation may simply be added to water in, for example, a bucket, applied with a cloth and wiped off with a squeegee.

Claims

1. A cleaning preparation for use in cleaning vehicle windscreens and the like comprising an aqueous solution which contains a cleaning agent and a watereoluble cellulose derivative.

2. A cleaning preparation according to Claim 1, wherein said water soluble cellulose derivative comprises sodium carboxymethylcellulose.

3. A cleaning preparation according to Claim 2, wherein the sodium carboxymethylcellulose comprises 0.2 to 10% by weight per total volume of the aqueous solution.

4. A cleaning preparation according to any one of the preceding claims, wherein said cleaning agent is volatile.

5. A cleaning preparation according to Claim 4, wherein said cleaning agent comprises 0.2 to 8% by weight per total volume of said aqueous solution.

6. A cleaning preparation according to Claim 4 or Claim 5, wherein said cleaning agent includes ammonia.

7. A cleaning preparation according to Claim 6, wherein said cleaning agent further includes phenol.

8. A cleaning preparation according to Claim 7, wherein the ratio of ammonia to phenol in said cleaning agent is such that the cleaning agent is mildly alkaline.

9. A cleaning preparation according to any one of the preceding claims, wherein the aqueous solution includes a wetting agent.

1 0. A cleaning preparation according to any one of the preceding claims, wherein said aqueous solution includes a freezing point depressant.

11. A cleaning preparation according to any one of Claims 1 to 8, wherein said aqueous solution includes isopropylalcohol.

12. A cleaning preparation according to Claim 1 substantially as hereinbefore described.

1 3. A washing solution for washing vehicle windscreens and the like comprising a mixture of a cleaning preparation in accordance with any one of the preceding claims, and water, wherein the cleaning preparation comprises 1 to 20% by volume of the washing solution.