US2386789A - Cleaning composition - Google Patents

Description

Patented Oct. 16, 1945 CLEANING COMPOSITION George W. Gregg, South Bend, Ind., assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware No Drawing. Application June 19, 1940,

Serial No. 341 ,275

Claims. (01.252-12'l) This invention relates to a cleaner and to the method of mixingand preparing the cleaner. It has for one object to provide 'a cleaner suitable for cleaning metal parts although its use is not limited to metal. One important use of the cleaner is to remove oil, grease, carbon, s ms; the stain from ethyl gasoline and contamination and foreign matter generally from metal and metal parts. Another object of the invention is to pro- 1 vide a cleaner of the type indicated which requires no special equipment and has no injurious efiects on the metal or metal parts themselves. Another object is to provide acleaner for use in cleaning metals which have ,been treated with .dicincmic and anodic treatments and which will not iniure such metals or destroy or counteract the efiects of such treatments. Metals which are commonly given such treatments are'zinc die-casttags and aluminum castings.

is highly stable and non-corrosive and which has a sufdciently high flash point to be safe in use without special precautions or special apparatus and which can be used cold.

The cleaner of this invention in one arrangement includes generally the following materials or their equivalents in the proportions indicated although some materials may be omitted, others may be substituted and the proportions may be varied:

v. Blending and thinning agent (sodium '01- ehromate) 2 Water (sumcient to dissolve the soap) 20 The specific materials above given are mentioned by way of illustration rather than by way of limitation. Many substitutions of equivalent materials are possible and many variations in the relative proportions of the materials are possible. One specific example of a substitution is that in the solvent either the ethylene-dichloride or the propylene-dichloride may be omitted and the remaining solvents increased proportionally.

While the cleaner has its present most import- V Another-object is .to provide a cleaner of the type indicated which drocarbons may be used.

ant use in cleaning metal, it may be used for other purposes to clean other materials, among them china and earthenware, bakelite and plastic generally, and many other materials.

It is important that a cleaner of this sort be as free from fire hazard as possible. When'mixed with the materials and in the proportions above indicated, the cleaner has a flash point of approximately degrees and a fire point of approximately degrees under agitation. When the material is not agitated, it will stratify; and when so stratifled, it has a flash point of approximately degrees. It has also the property that the least inflammable materials come to the top and hence reduce the fire danger. Another important purpose, as a result of the stratification, is that those materials which come to the-top protect the more volatile materials which tend to lie lower in the mixture and prevent their evaporation and thus prevent waste. In general. the material which comes to the surface when the material is allowed to stand is a mixture of water and soap and sodium bichromate. Other materials may, of course, be mixed with the upper.

stratum but those mentioned make up the upper ody of that stratum.

in general, the material is used without any agitation. After preparation it is put into an open tank of suitable size for the'size' of the parts which are to be cleaned. The Parts are put into it, allowed to soak for a few minutes and then removed. Should agitation be desired. it may be applied and tends to hasten the action as is generally the case with almost all cleaners.

but agitation is not necessary for commercial use and success.

As above noted the materials and proportions set out in the table above are illustrative rather than limiting. The solvent has primarily the function of weakening the bond between certain foreign material and the metal to which it has adhered so that the foreign material, including greases, gums and the like, is removed from the metal without being fully dissolved. The purpose of the solvent is, therefore. to dissolve whatever it is that causes the bond of contamination and the foreign matter generally to adhere to the metal. While unchlorinated hydrocarbons mi ht be used, their solvent power and ability are les Chlorinated hydrocarbons have a greater solvent ability and are efi'ective on a larger number f materials. Only two hydrocarbons are specifically mentioned in the table above. However. any chlorinated hydrocarbons or any mixture of hy- The soap is used for its detergent action. It tends to surround the particles of foreign matter. It tends to break down the surface tension of the foreign matter and contamination. The solvent present breaks the-bond between the foreign matter and the metal, and the soap tends to surround the matter after its bond is broken.

When the foreign matter has thus been broken away from the metal and surrounded with soap, it sinks or floats, depending upon its weight; and when the cleaner is quiet, as when it is out of use, the foreign matter sinks when stratification of the material occurs and settles to the bottom as sludge. It does not go to the top of the material and scum is not formed. Practically all of the foreign matter settles to the bottom as sludge. While vegetable oil soap has been mentioned and is preferable, others may be used. One advantage of vegetable soap is that it dissolves readily in cold water.

The penetrant which is mentioned may be any of the cresols or phenol or cresylic acid or tar acid. Preferably, as above mentioned, a tar acid oil of the low boiling range is used which contains not less than fifty per cent tar acid. The penetrant, which is the third ingredient in the list set out above, penetrates the contamination to permit the rapid action of the solvent and the detergent. The penetrant has to some extent a solvent action itself. The penetrant is properly considered as primarily a softener.

The coupling agent, which may also be considered a blending agent, is preferably normal butyl alcohol. In the cleaner of this invention, the butyl alcohol acts as a coupling agent for the solvent and the detergent and it thins the emulsion; hence, reducing the drag-out." When parts which have been cleaned are removed from a body of the cleaner, that portion of the cleaner which sticks to them and is carried out and lost is called the drag-out." It is, of course, an advantage to reduce this as far as possible and one of the effects of the coupler is to thin the material, particularly, the emulsion, and to limit or reduce the drag-out. The coupler is not merely a thinner, however, but it causes a chemical coupling of the molecules of one material with the other. A mere thinner such as waterwould not have the true coupling efiect required.

The anti-foaming agent has the effect of further reducing the drag-out. If the material were highly foamy, which would otherwise be the case, a larger quantity of the cleaner would be lost as drag-out when the articles which have been cleaned are removed through the foam because appreciable quantities of foam would adhere to the articles and be lost with them. Other alcohols might be used, including methyl alcohol, and a variety of denatured alcohols might be used, including the formula Fl3. Experience has shown that although many alcohols may be used, synthetic ethyl alcohol is of particular advantage. It is uniform and cheaper than natural grain alcohol and readily obtainable.

A preservative is used to prevent rancidity. Animal fats and greases are frequently taken into the cleaner during its use. It is important to prevent rancidity of these products present in the cleaner or in the sludge which settles from it. Since the rosin is present in the cleaner, it acts upon the fats as soon as they are taken up. The fats tend to move promptly into the sludge and since the sludge may be present for quite a long while rancidity would occur were it not for the presence of the preservative. The fats tend might be used but rosin is a satisfactory one and is suillciently cheap for normal commercial use.

The blending and thinning agent, referred to as the seventh ingredient in the above table, ef- I fects a coupling between the solvent and the soap solution and a blending between the soap solution and the tar acids and between the double soap solution and the solvent which is partially coupled by the butyl alcohol. Sodium bichromate is referred to as a suitable blending and thinning agent. Without the presence of the sodium bichromate, the soap would have a tendency to separate, particularly upon stratification of the material when quiet. Also, an unstable emulsion is produced. The advantage of the unstable emulsion is that when the dirt is separated from the metal from which it is being cleaned, it is not suspended in the cleaner but is permitted to sink. While sodium bichromate is a suitable blending and thinning agent, there are others, among them potassium bichromate. Before the sodium bichromate is added, there is a clear soap solution. When the acids are put in they tend to curdle the soap and this curdling is prevented or the tendency for its occurrence is overcome by the sodium bichromate or other blending and thinning agent.

The eighth ingredient in the list above is water. It acts as a solvent for some of the materials. Other materials might be used instead. Alcohol might be used but it would not be as satisfactory as the detergent action which soap has with water would be reduced or destroyed. The presence of water effects a more complete removal of the contamination by increasing the detergent action of the soap.

In considering the proportions of the ingredients above, it has been said that they may be varied. For example, the solvent might be present from ten to thirty per cent of the total and other similar variations might be made.

While the material may be mixed in several different ways and while the ingredients do not have to be put in a fixed order, experience has shown that the following is a satisfactory order of mixing:

1. The tar 'acid 'is put into the mixing vat.

2. The solvent. and the soap are mixed separately and the butyl alcohol is added. This mixture of solvent, soap solution and butyl alcohol is then put into the tar acid.

3. The rosin may be added to the soap or it may be present in the alcohol when the alcohol is added to the solvent and soap solution.

4. The sodium bichromate is then added.

5. During the adding and mixing the material is agitated in whatever vessel it is being mixed in. Mixing takes place at ordinary room temperatures and when it is completed the desired quantity of the cleaner may be removed and used.

I claim:

1. In a stratified surface cleaner for cleaning relatively hard materials, the combination of the following stratifying materials: a solvent comprising one of the chlorinated hydrocarbons, a detergent comprising a vegetable oil soap, :1 penetrant comprising a tar acid. oil, a coupling agent comprising normal butyl alcohol, an antifoaming agent comprising ethyl alcohol, a preservative comprising rosin, a blending and thinning agent comprising sodium bichromate, and water.

2. In a surface cleaner for cleaning relatively hard materials, the combination of the following materials: a solvent comprising one of the chlorinated hydrocarbons, a detergent comprising a vegetable oil soap, a penetrant comprising a 50 per cent tar acid oil, a coupling agent comprising normal butyl alcohol, an anti-foaming agent comprising ethyl alcohol, a preservative comprising rosin, a blending and thinning agent comprising sodium bichromate, and water.

3. In a surface cleaner for cleaning relatively hard materials, the combination of the following materials: a solvent comprising one of the chlorinated hydrocarbons, a detergent comprising a vegetable oil soap, a penetrant comprising a tar acid oil, a coupling agent comprising normal butyl alcohol, an anti-foaming agent comprising denatured ethyl alcohol, a fat preservative comprising rosin, a blending and thinning agent comprising sodium bichromate, and water.

4. A cleaning bath for metallic articles adapted to be immersed therein and whose surfaces are contaminated with oils, greases, gums, fats,

' carbons and other contaminating substances,

said bath consisting of a solvent comprising one of the chlorinated hydrocarbons selected from the group consisting of ethylene-dichloride and propylene-dichloride, approximately 20 per cent; a detergent comprising a vegetable oil soap, approximately 10 per cent; a penetrant selected from the group consisting of cresol, phenol, cresylic acid and tar acid oil, approximately 33 per cent; a coupling agent comprising normal butyl alcohol, approximately 8 per cent; an anti-foaming agent comprising ethyl alcohol, approximately 6 per cent; a preservative for preventing rancidity of the contaminating substances removed from the metal articles by the bath, said preservative comprising rosin, approximately 1 per cent; a blending and thinning agent selected from the group consisting of sodium bichromate and potassium bichromate, approximately 2 per cent; and water, approximately 20 per cent.

5. A cleaning bath for metallic articles adapted to be immersed therein and whose surfaces are contaminated with oils, greases, gums, fats, carbon and other contaminating substances, said bath consisting of a solvent comprising ethyl- GEORGE W. GREGG.