Biocidal compositions are provided comprising a mixture of o-phenylphenol and 2,2'-methylene bis(4-chlorophenol). Said compositions advantageously include a surface active agent which is stable under basic conditions. There are also provided aqueous solutions comprising the above biocidal compositions.

The present invention relates to biocidal compositions. There are known 
many biocides, many of them being phenol derivatives. One of said biocidal 
phenol derivatives is o-phenylphenol. Said compound is quite effective 
against a broad range of micro-organisms. However, when used against 
certain other bacteria, in particular against Pseudomonas species which is 
a wide spread bacteria well known to be an especially biocidal resistant 
bacteria relatively high levels of said phenol are required. 
Another known effective biocidal phenol derivative is 2,2'-methylenebis 
(4-chlorophenol) (hereinafter called "dichlorophene"). This compound is 
also effective against a broad range of micro-organisms. However, it is 
less effective then o-phenylphenol against Pseudomonas species. 
U.S. Pat. No. 3,824,190 describes and claims a phenolic-synthetic detergent 
disinfectant composition comprising a mixture of o-phenylphenol and a 
phenol selected from the group consisting of 4-chloro-2-cyclopentylphenol, 
4-chloro-2-benzylphenol, 4-chloro-2-phenolphenyl, 6-chloro-2-phenylphenol, 
4-5-amylphenol, 4-n-amylphenol, 2,4-dichloro-3,5-dimethylphenol, 
4-chloro-3,5-dimethylphenol, 5-methyl-2-isopropylphenol, and ortho 
chloro-p-phenylphenol. It is stated in the specification that said 
composition is effective, inter alia, against Pseudomonas in hard water. 
However, the amount of composition required is at least 750 ppm of which 
at least 450 ppm should be o-phenylphenol. This composition constitutes a 
certain improvement. However, in order to obtain satisfactory biocidal 
efficacy relatively high levels of the compositions are required. 
It has now been found that when one utilises a biocidal composition 
comprising a mixture of o-phenylphenol and dichlorophene, the desired 
biocidal effect is achieved with a composition comprising lower levels of 
each of the effective compounds, i.e. a synergistic effect is observed. As 
will be shown hereinafter this synergistic effect is especially strong 
under actual field conditions, i.e. in the presence of organic soil. 
The present invention thus consists in a biocidal composition comprising as 
active components a mixture of o-phenylphenol and 2,2'-methylene 
bis(4-chlorophenol) (dichlorophene). 
In a preferred embodiment of the invention, said composition also comprises 
a surface active compound which is stable under basic conditions, for 
example, certain anionic surface active compounds, e.g. aliphatic 
sulfonates, sulfonates of aliphatic-aromatic hydrocarbons, ester 
sulfonates, amide sulfonates, and sulfonates containing ether, amino, keto 
and sulfone groups, as well as those obtained from sulfated fatty 
alcohols, sulfated fatty condensation products such as sulfated 
ethoxylated primary or secondary alcohols, and sulfated fatty glycerides, 
acids, esters, phosphates, and modified carboxylates, and mixtures 
thereof. 
The composition according to the present invention is preferably applied in 
the form of the aqueous solution. The active compounds which as such are 
sparingly soluble in water are for this purpose utilized in the form of 
their sodium salts. Said sodium salts may be used as such or prepared in 
situ. 
In order to save transport costs the composition is either sold in dry form 
or as a relatively concentrated aqueous solution. The amount of active 
components in the concentrated solution is preferably 30-50% and the 
amount of the surfactant, if present, is preferably 1.5-3.5%, all 
percentages being percentages by weight. Said solution can be diluted to 
the recommended use concentration, i.e. about 2-3 ml/L water. As will be 
shown hereinafter total concentrations of 500 ppm i.e. of 250 ppm of 
o-phenyl-phenol or even less, are very effective. This certainly 
constitutes a considerable advantage in comparison to the known 
compositions, which require higher levels. 
The ratio of o-phenylphenol:dichlorophene may vary to a large extent. 
However, it appears that the most effective ratio is between 2:1 to 1:3. 
The biocidal composition according to the present invention is not only 
effective against Pseudomonas but also against many other bacteria, such 
as Staphylocci, Streptococci, Brucella, Enterobacter, E. Coli, Proteus, 
Shigella and Salmonella. Moreover, it is effective against viruses in 
particular byophilic viruses such as: 
Newcastle Disease--Acute Asian type as in Israel--(Velogenic Visceral 
Newcastle Disease); 
Herpes simplex--Mareks Disease in Poultry; 
Infectious Bronchitis; 
Infectious Laryngotracheitis; 
Influenza A2 Virus; 
Adenovirus; 
Vaccinia--Virus Causing Fox 
The composition according to the present invention is also a broad spectrum 
fugicide. It kills algae, yeast, fungi and moulds. It prevents slime 
formation. 
The composition according to the present invention is stable in the 
presence of organic matter. It retains its activity even in exaggeratedly 
hard water (over 700 ppm CaCO.sub.3). It has a low toxicity. 
In view of the above it is readily understood that the biocidal composition 
according to the present invention can be widely used in farm, home, 
hospital and industry. The low concentration of active components required 
and the high degree of efficacy makes the use very economical and safe. 
The composition according to the present invention is prepared by methods 
known per se, i.e., by conventional mixing and dissolving operations. 
The present invention will now be illustrated by the following examples 
without being limited by them. 
In said examples the following solutions were utilized: a. 40% aqueous 
solution of dichlorophene and 2.1% of sodium lauryl ether sulfate. b. 40% 
aqueous solution of o-phenylphenol and 2.1% of sodium lauryl ether 
sulfate. Said solutions were mixed and/or diluted as required. 
Wherever in the Examples a "composition" is stated this means a composition 
according to the present invention, i.e. a mixture of o-phenylphenol and 
dichloropheene. As in the case of a. and b. the composition also include 
the surfactant. 
As Pseudomonas species there are utilised human, chicken and cattle strains 
of Pseudomonas aerogunosa. Said strains were isolated gt the Kimron 
Veterinary Institute from clinical outbreaks. 
The microbioligical results were obtained as per the following procedure: 
Bacterial dilutions of a fresh culture of the appropriate strain were 
incubated for 18 hours at 37.degree. C. 0.2 ml of the bacterial culture at 
a concentration of 1.times.10.sup.7 were then introduced into 1.8 ml of 
the appropriate dilution of the biocide. There was thus obtained a final 
bacterial concentration of 1.times.10.sup.6. 
After the stated contact time of the bacteria with the biocidal solution 
0.1 ml of the solution was removed and introduced into 9.9 ml of 
physiological solution in order to neutralize the activity of the biocide. 
Two samples were taken from said solution and each introduced into a 
nutrient broth (pH 7.2). A third sample was taken and introduced into a 
test-tube containing physiological solution. From the latter test-tube 
containing the physiological solution a sample was taken and added to a 
nutrient broth (pH 7.2). 
The test tubes with the broth were then incubated for 18 hours at 
37.degree. C. and the presence of bacteria was checked and determined.