US 2901395 A
Description (OCR text may contain errors)
United States Patent O COPPER PENTACHLOROPHENATE SOLUTION Charles Parkes Matzinger, Berkeley, Calif., assignor to The Mountain Copper Company, Ltd., a corporation of Great Britain No Drawing. Application April 28, 1958 Serial No. 731,122
4 Claims. (Cl. 167-42) This application is a continuation-in-part of my application Serial No. 533,496, filed September 7, 1955, now abandoned.
This invention relates to a method for the preservation of wood and particularly relates to a novel wood preservative containing copper pentachlorophenate.
Copper pentachlorophenate has heretofore been used as a preservative of wood, but it has previously been necessary to incorporate copper pentachlorophenate into the wood by means of a complicated technique. Thus, it is first necessary to form a cuprammonium salt of copper and add this to pentachlorophenol in the presence of a dilute, water soluble solvent to produce an arnmoniacal solution of copper pentachlorophenate. This solution must then be used at an elevated temperature and pressure, so the treatment is complicated and expensive. Further, since the compound is used with a solvent which evaporates, the copper pentachlorophenate is deposited in solid form and loses its ability to migrate, and thus does not protect against fresh cuts or holes which may develop in the wood.
It is therefore one object of the present invention to provide a stable, non-volatile solution of copper pentachlorophenate which readily penetrates wood and which may be used with or without pressure.
Another object of the invention is to provide a solvent for copper pentachlorophenate which does not require the use of ammonia.
Still another object of this invention is to provide a formulation of copper pentachlorophenate which gives protection to treated wood for an extended period of time and particularly gives potection against fresh injuries to the wood.
A further object of this invention is to provide a pentachlorophenate which is easy to store and ship and which can be diluted before use with relatively inexpensive solvents.
In general, the objects of the present invention are accomplished by utilizing a solvent sold commercially as Lebcol T-40. Lebcol T40 is a mixture of the methyl esters of the fatty acids of tallow and is capable of dissolving copper pentachlorophenate; copper pentachlorophenate may be dissolved in Lebcol T-40 directly, or the process can be speeded up by employing a bridging solvent, such as ethanol or hexylene glycol.
It is possible to incorporate the copper pentachlorophenate into the Lebcol T-40 directly. In general, about 5% copper pentachlorophenate may be incorparted in the Lebcol solution in this manner. However, a preferred solution contains only about 3% copper pentachlorophenate for when efiorts are made to incorporate greater quantities somewhat unstable solutions are formed. A temperature of 130-140 C. for a period of about half an hour is preferably employed as a means of aiding the solubilization of the copper pentachlorophenate in the Lebcol T-40. The purpose of heating to such a temperature is to remove water whereby to produce a stable solution.
fiililllbll ICC Improved results are obtained by mixing the copper pentachlorophenate with Lebcol T-40 in the presence of a bridging solvent such as ethanol or hexylene glycol. Where ethanol is used, a temperature in the neighborhood of -140 C. for one-half hour is necessary, as above, to drive off the water present in the alcohol. Where hex ylene glycol replaces the alcohol, substantially lower temperatures are possible, such as set forth in Example 6 below.
Where only Lebcol T40 and hexylene glycol are present, it is possible to place as much as 40% of the copper pentachlorophenate in solution. This, however, is not ordinarily a stable solution and it is preferred that no more than about 25% copper pentachlorophenate, as set forth in the examples, is incorporated in the solution containing the hexylene glycol and Lebcol. Where only Lebcol and ethanol are present, the 5% maximum mentioned above applies with 3% being the preferred concentration of the copper pentachlorophenate in solution.
The preferred method, however, for the preparation of the copper pentachlorophenate solution is by the in situ preparation of the copper pentachlorophenate in the solvent. The copper pentachlorophenate as produced by the method set forth in my copending patent application, Serial No. 521,629, filed July 12, 1955, is suitable for practicing the present invention. In that application, a method is shown of making copper pentachlorophenate by reacting pentachlorophenol with copper hydroxide in a solution of ethyl alcohol. This results in the production of copper pentachlorophenate dissolved in from one to two parts of alcohol per part of copper pentachlorophenate. The copper pentachlorophenate alcohol solution can then be added to the Lebcol T-40 to produce a solution containing as much as about 5% copper pentachlorophenate.
Better results are secured where hexylene glycol is used in place of ethyl alcohol, as set forth in Example 6 below. Far lower temperatures are possible since there is no necessity for driving oli water and, as indicated above, much larger quantities of the copper pentachlorophenate may be dissolved. The percentages are as set forth above, a 40% absolute maximum with 25 being a preferred maximum in solution.
By heating a mixture of Lebcol T-40 and copper pentachlorophenate together at a temperature of from 130- C. for about one-half hour, the two form a solution either with or without the use of a bridging solvent. Further, the heating prevents the subsequent formation of a residue which sometimes happens where bridging solvent is used without heating.
Where more water is present than can be handled readily by the coupling agent, the residue formation seems to take place more readily. Hence, the advantage of heating to drive off water.
The use of ethylene glycol in combination with Lebcol T-40 presents an additional advantage. When this mixture is used, it is possible to use substantial quantities of inexpensive solvents such as the aromatics, paint thinners, and others (but excluding kerosene and the like). The less volatile extenders are preferred, such as Aromatic Solvent 42, since the wood penetration of copper pentachlorophenate is greater if the carrier is present for a longer period of time. Where Lebcol T-40 alone or a combination of Lebcol T-40 and ethanol are present without the ethylene glycol, it is found that there is an insufliciently strong coupling agent present to hold copper pentachlorophenate in solution should quantities of paint thinner or stove oil be added. Hence, it is preferred to use substantial quantities of extenders only where the ethylene glycol is used.
The following examples illustrate how solutions may be formed:
Example I.About 3.5 grams of pentachlorophenol in 50 ml. ethanol is added with agitation to 0.45 gram of copper hydroxide. When solution is complete, 50 m1. of Lebcol T-40 is added and the mixture is heated to 130 C. for one-half hour. The mixture is then cooled and more Lebcol T-40 is added to make a total of 100 grams. The solution contains 3% copper pentachlorophenate and a slight excess of pentachlorophenol. This is more concentrated than is necessary for use and can be diluted to a /2% solution either with more Lebcol T-4O or with a solvent such as Aromatic Petroleum Solvent 42.
Example 2.A mixture containing 0.45 gram copper hydroxide, 3.5 grams of pentachlorophenol and 50 ml. of Lebcol T-40 was agitated until all of the pentachlorophenol had gone into solution. The mixture was then gradually heated to 130 C. and held at this temperature for one-half hour. The solution was then diluted with additional Lebcol T-40 to make 100 grams and remained stable.
The following examples illustrate the formation of concentrated solutions of copper pentachlorophenate. In Examples 3-5, the copper pentachlorophenate is made in situ by first mixing the hexylene glycol and Lebcol T-40. The pentachlorophenol and copper hydroxide are then slowly added with continuous stirring. The solution is warmed slightly (30 C.) and is stirred for 20 to 30 minutes. A stable solution of copper pentachlorophenate is thus produced which can be employed directly in wood preserving, or which can be diluted to the desired concentration with additional Lebcol T-40 or with less expensive solvents such as Aromatic Petroleum Solvent 42, paint thinner, or the like.
Example 3.To make (by weight) concentration of copper pentachlorophenate:
Formula 45 lbs. hexylene glycol 45 lbs. Lebcol T-40 9 lbs. pentachlorophenol 1.5 lbs. copper hydroxide Example 4.To make concentration of copper pentachlorophenol:
Formula 40 lbs. hexylene glycol 40 lbs. Lebcol T-40 18 lbs. pentachlorophenol 3 lbs. copper hydroxide Example 5.To make concentration of copper pentachlorophenol:
Formula 37 /2 lbs. hexylene glycol 37 /2 lbs. Lebcol T-40 22 /2 lbs. pentachlorophenol 3% lbs. copper hydroxide In the above examples, the copper pentachlorophenate was formed in situ in the presence of the Lebcol T-40. However, it is also possible to form the copper pentachlorophenate in hexylene glycol and then add the Lebcol T-40, as is shown in the following example.
Example 6.About 45 pounds of hexylene glycol, 9 pounds of pentachlorophenol and 1.5 pounds of copper hydroxide were stirred together at 30 C. for 20 minutes. This solution of copper pentachlorophenate in hexylene glycol was then added to 45 pounds of Lebcol T40 and stirred to produce a solution having the same characteristics as that of Example 3.
In the following example, the copper pentachlorophenate was not made in situ, but the solution was prepared from previously made copper pentachlorophenate:
Example 7.-To 20 pounds of copper pentachlorophenate there were added with stirring 40 pounds of hexylene glycol and 40 pounds of Lebcol T-40. This produced a solution having the characteristics of Example 4.
The solutions prepared as above may then be used to treat lumber in any desired manner. Although pressure treatment is entirely feasible with the solution, it has generally been found that pressure treatment does not offer any particular advantage since the composition of the present invention readily penetrates the wood upon contact. Further, since the composition is not volatile, it is retained by the wood for an indefinite length of time. When the composition of the present invention is used, it remains a liquid and continued protection is offered as holes or cuts develop in the wood. The wood may be preserved by merely dipping it into the solution, or the solution may be painted onto the surface of the wood. One attractive alternative is the employment of hot and cold dipping.
One indication of the penetrating powers of the solution of the present invention is shown by the fact that 1.4 ml. of a solution prepared as in Example 1 was applied drop-wise to the surface of a fir board. In a period of twenty-four hours, the solution traveled completely through the board and could be observed on the opposite side.
1. As a new composition of matter a mixture of copper pentachlorophenate and the methyl esters of tallow fatty acids.
2. The composition of claim 1 wherein the copper pentachlorophenate constitutes about 3% of the mixture.
3. The composition of claim 1 wherein ethyl alcohol is present.
4. The composition of claim 1 wherein hexylene glycol is present.
References Cited in the file of this patent UNITED STATES PATENTS UNITED STATES PATENT orrrss CERTIFICATE OI CORRECTION Patent No. 2,90l,395 August 25, 1959 Charles Parkes Matzin'g er It is hereby certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.
Column 2, lines 56, 6'7, and '72, for "ethylene"', each occurrence, read hexylene Signed and sealed this 12th day of April 19609 (SEAL) Attest:
KARL H AXLINE ROBERT C. WATSON Attesting Officer Commissioner of Patents