Synergistic Biostatic Composition

Biocidal compositions for contact sterilization are well known and much has been published on the composition and uses. The composition of this invention, however, has a number of advantages that are superior to those of prior compositions of which applicants are aware in that the active ingredients have low toxicity to animals and the composition is easily made, is active even in small proportions, and is stable while exerting its biocidal properties. One of the features of this invention, therefore, is to provide an improved biocidal composition, as disclosed above, and employing the above ester in combination with two biocides of the class consisting of 2,3,5,6 Tetrachloro 4, (methylsulfonyl) pyridine; 2,4,4 Trichloro-2-Hydroxydiphenyl ether; 3,7 Dichlorodibenz (be) (1,4) oxiodinium bisulfate; 3, Chlorodibenz (be) (1,4) oxiodinium chloride; Dibenz (be) (1,4) oxiodinium chloride; a(2,4 Dichlorophenyl) a-phenyl 5-pyriridine methanol; 4, Chloro-2-cyclopentyl phenol; 3,4,5 Tribromosalicylanilide; 3,5 dimethyl-tetrahydro 1,3,5,2 H-thiodiazine-2 thione; Diphenyl-stilbene 2 ethyl hexoate; 4 Chloro-3 methylphenol; 10,10, oxybisphenoxyarsine; paratertiary amyl phenol; and phenyl 3 iodo 2-propynyl ether.

Other possible biocides are Tributyl tin fluoride, Di(phenylmercury) dodecenylsuccinate, 2(4 thiazolyl) benzimidazole, Barium metaborate, and Hexachlorophene, as well as others, but, for various reasons, are not preferred.

The ester has the probable structural formula ##STR1## in which R, R', and R" are the same or different alkyl groups, with each having from one to 17 carbon atoms and the two biocides may be any pair selected from the above class. Although the invention is not limited by any theory, either stated or implied herein, it is believed that these three components form a closed triangle. It is also believed that each biocide links with the TA-100 as an alkyl group to give an exposed electron for linking with the other biocide.

The ester is sometimes identified herein as TA-100. It is present in the three-component biocidal composition (synergistic solution) in an amount of about 25-55%. One of the two biocides is present in the amount of about 29-69%, and the other in the amount of about 6-16%, for a total of 100%. All percentages herein are by weight. It is believed that the two biocides combine or react with the TA-100 by addition with the alkyl groups or possibly by electrophylic substitution. It has the effect of forming a three-member complex with an inhibitory and, even, a killing action against bacteria and fungi to provide contact sterilization.

The TA-100, when complexed as described with the two biocides, results in a biocidal composition having increased effectiveness over the sum of the effectiveness of the two biocides added together. In other words, the TA-100 acts as a true synergist, even though it has no cidal activity toward bacteria of its own. Furthermore, the biocidal activity of the resulting three-component complex is directly proportional to the amount of the TA-100 ester and with synergistic activity being noted so long as the amount is at least 20% of the complex composition, although, as stated above, the preferred minimum amount is about 25%.

In the above ranges of amounts of the three components in the complex, it should be understood that a composition having biocidal characteristics could be produced outside these ranges of amounts but for practical reasons these ranges are preferred.

The TA-100 ester can be generally classified as the reaction product of an amino hydroxy compound, an organic carboxylic acid, and an aldehyde. The chemical combination or reaction of the TA-100 with the two biocides creates a synergistic complex which is believed to be of closed structure and has the ability to impregnate the systems carrier so as to achieve a homogeneous distribution throughout the system, thereby increasing the biocidal surface that acts as a barrier to microbial attack.

The biocidal composition which is effective as a fungicide and bacteriocide is usable in sterilizing compositions, paints, surface coating materials such as plastics, cosmetics, soaps, salves, ointments, deodorants, lotions, shampoos, skin creams, and pharmaceuticals such as gargles and sterilizing sprays when employed with the customary carriers, such as ointment bases, and thus find very effective use in coatings, tile sealant, air filter protective sprays, vinyl cover adhesives, protective floor coverings, and in grout mixes. Although the biocidal composition is usable with water-based systems of pH4-9, it is also usable with oils or resinous organic liquid bases.

In order to prepare the biocidal composition, the mixture of TA-100 and the two biocides is mixed with high shear and at the temperature, in the area of room temperature or above at which time the solubility and the complexing of the compounds is effected.

The following examples illustrate the invention:

The above compositions may be used as such or may be added directly to completed pigmented coating materials as concentrates or they can be included in the formula during manufacture of pigmented coating materials. The amount of the biocidal composition three-component complex used in the formulas can be any amount desired but, ordinarily, will be from about 0.5% to about 10% by weight of the formulation. Examples of such formulations are as follows:

A coating primer for providing a microbial control coating on a solid surface has the following ingredients:

A semi-gloss coating with biocidal characteristics has the following formula:

In preparing the above formulation, the ingredients were mixed in a high speed disperser, such as a Cowles Dissolver (a trademark of the Morehouse-Cowles Corporation), by first adding the liquid of the first ingredient and then adding the listed ingredients through the titanium dioxide, while stirring from thirty minutes to one hour at high speed to provide a dispersing action. Then, the remaining ingredients were added at a lower speed over a period of twenty minutes.

An example of a biocidal synergistic composition has the following ingredients:

The ingredients down through Tamol 731 were mixed for five minutes in a Cowles tank, then the TA-100 was added and mixed for an additional ten minutes and, finally, the last two ingredients were sifted into the tank and mixed for about fifteen minutes until well-dispersed in the other ingredients to provide a substantially homogeneous composition.

In this example, there is produced a flat paint having excellent washability characteristics. This formulation has the following ingredients:

In preparing this material, the water was added to the clean Cowles tank. Then, the methocel was sifted slowly into the water together with the ammonium hydroxide to dissolve the methocel, and the whole was mixed for about twenty minutes. Then, the K.T.P.P. and following-listed ingredients, through the titanium dioxide pigment were added and the speed of mixing was increased to provide a dispersing action and this was continued for about thirty minutes. At the end of this time, the additional water was added slowly at low speed and, finally, the remaining ingredients were added slowly at the lowest speed and the whole was mixed for an additional twenty minutes.