Microbicidal compositions and methods using combinations of propiconazole with dodecylamine or a dodecylamine salt

Microbicidal compositions are described. The compositions contain (a) propiconazole and (b) dodecylamine or a dodecylamine salt. The propiconazole and dodecylamine or dodecylamine salt are present in a synergistically effective amount to control the growth of at least one microorganism. Methods for controlling the growth of microorganisms on various substrates or in aqueous systems are also described. Also described is the industrial application of the microbicidal composition in the leather industry, the lumber industry, the papermaking industry, the textile industry, the agricultural industry, and the coating industry, as well as in aqueous systems.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to compositions for controlling the growth of 
microorganisms on a variety of substrates and in aqueous systems. More 
particularly, the invention relates to combinations of propiconazole, also 
known as 
(RS)-1-2-(2,4-dichlorophenyl)-2-propyl-1,3-dioxalan-2-ylmethyl!-1H-1,2,4- 
triazole, with dodecylamine or a dodecylamine salt. The invention also 
relates to the use of such combinations as microbicides. 
2. Background of the Invention 
A large variety of commercial, industrial, agricultural, and wood materials 
or products are subject to microbiological attack or degradation which 
reduces or destroys their economic value. Examples of such materials or 
products include surface coatings, lumber, seeds, plants, leather and 
plastics. The various temperatures at which such materials or products are 
manufactured, stored, or used as well as their intrinsic characteristics 
make them susceptible to growth, attack, and degradation by common 
microorganisms such as algae, fungi, yeasts, and bacteria. These 
microorganisms may be introduced during a manufacturing or other 
industrial process, by exposure to air, tanks, pipes, equipment, and 
humans. They can also be introduced while using a material or product, for 
example, by multiple openings and reclosures of packages or from stirring 
or removing material with contaminated objects. 
Aqueous systems are also highly subject to microbiological growth, attack, 
and degradation. The aqueous system may be a fresh, brackish or saltwater 
system. Exemplary aqueous systems include, but are not limited to, 
latexes, surfactants, dispersants, stabilizers, thickeners, adhesives, 
starches, waxes, proteins, emulsifying agents, cellulose products, metal 
worlking fluids, cooling water, waste water, aqueous emulsions, aqueous 
detergents, coating compositions, paint compositions, and resins 
formulated in aqueous solutions, emulsions or suspensions. These systems 
frequently contain relatively large amounts of water and organic material 
causing them to be environments well-suited for microbiologic growth and 
thus attack and degradation. 
Microbiological degradation of aqueous systems may manifest itself as a 
variety of problems, such as loss of viscosity, gas formation, 
objectionable odors, decreased pH, emulsion breaking, color change, and 
gelling. Additionally, microbiological deterioration of aqueous systems 
can cause fouling of the related water-handling system, which may include 
cooling towers, pumps, heat exchangers, and pipelines, heating systems, 
scrubbing systems, and other similar systems. 
Microbiological degradation can have a direct adverse economic impact when 
it occurs in industrial process waters, for example in cooling waters, 
metal working fluids, or other recirculating water systems such as those 
used in papermaking or textile manufacture. If not controlled, 
microbiological degradation of industrial process waters can interfere 
with process operations, lower process efficiency, waste energy, plug the 
water-handling system, and even degrade product quality. 
For example, cooling water systems used in power plants, refineries, 
chemical plants, air-conditioning systems, and other industrial operations 
frequently encounter microbiological degradation problems. Airborne 
organisms entrained from cooling towers as well as waterborne organisms 
from the system's water supply commonly contaminate these aqueous systems. 
The water in such systems generally provides an excellent growth medium 
for these organisms. Aerobic and heliotropic organisms flourish in the 
towers. Other organisms grow in and colonize such areas as the tower sump, 
pipelines, heat exchangers, etc. If not controlled, the resulting 
microbiological degradation can plug the towers, block pipelines, and coat 
heat-transfer surfaces with layers of slime and other biologic mats. This 
prevents proper operation, reduces cooling efficiency and, perhaps more 
importantly, increases the costs of the overall process. 
Industrial processes subject to microbiological degradation also include 
papermaking, the manufacture of pulp, paper, paperboard, etc. and textile 
manufacture, particularly water-laid non-woven textiles. These industrial 
processes generally recirculate large amounts of water under conditions 
which favor the growth of microbiological degradation organisms. 
Paper machines, for example, handle very large volumes of water in 
recirculating systems called "white water systems." The furnish to a paper 
machine typically contains only about 0.5% of fibrous and non-fibrous 
papermaking solids, which means that for each ton of paper almost 200 tons 
of water pass through the headbox. Most of this water recirculates in the 
white water system. White water systems provide excellent growth media for 
microbiological degradation organisms. That growth can result in the 
fromation of slime and other deposits in headboxes, waterlines, and 
papermaking equipment. Such microbiological degradation not only can 
interfere with water and stock flows, but when loose, can cause spots, 
holes, and bad odors in the paper as well as web breaks, all of which 
translate into costly disruptions in paper machine operations. 
Slime formation can occur in other aqueous systems including fresh, 
brackish or salt water systems. Slime consists of matted deposits of 
microorganisms, fibers and debris. It may be stringy, pasty, rubbery, 
tapioca-like, or hard, and may have a characteristic undesirable odor that 
is different from that of the aqueous system in which it formed. The 
microorganisms involved in its formation are primarily different species 
of spore-forming and nonspore-forming bacteria, particularly capsulated 
forms of bacteria which secrete gelatinous substances that envelop or 
encase the cells. Slime microorganisms also include filamentous bacteria, 
filamentous fungi of the mold type, yeast, and yeast-like organisms. Slime 
reduces yields in production and causes plugging, bulking, and other 
problems in industrial water systems. 
Various chemicals known as industrial microbicides have been used to 
prevent microbiological deterioration or degradation of industrial 
systems, raw materials, and products. Some of these biocides, however, are 
of questionable practical utility because they have undesirable odors, are 
high in cost, show low degree of effectiveness or create hazards with 
respect to storage, use, or handling. For instance, the use of such 
popular industrial microbicides as organomercurial compounds, organotin 
compounds and chlorinated phenols have come under great regulatory 
pressure in recent times because of their high toxicity and concern about 
their adverse effects on the environment. 
Propiconazole, also known as 
(RS)-1-2-(2,4-dichlorophenyl)-2-propyl-1,3-dioxalan-2ylmethyl!1H-1,2,4-tr 
iazole, is one commercial biocide which has been shown to have a reasonably 
good toxicological profile and biocidal activity. However, at low 
concentrations, propiconazole may have a relatively narrow antimicrobial 
spectrum and may not completely prevent the growth of microorganisms. 
Despite the existence of current microbicides, workers in the trade have 
continued to seek improved biocides which possess low toxicity while 
exhibiting a prolonged biocidal effect at normal use levels. The improved 
microbicide should also preferably be more economical and cost-effective 
offering equal or better protection at lower cost and lower concentration. 
The concentration of conventional microbicides and the corresponding 
treatment costs for such use, can be relatively high. Thus, important 
factors in the search for improved microbicides include the duration of 
microbicidal effect, the ease of use, and the effectiveness of the 
microbicide per unit weight. 
SUMMARY OF THE INVENTION 
In view of industry's search for improved microbicides, the present 
invention offers an improvement over current biocides and practices. A 
first embodiment of the invention provides a microbicidal composition. 
This composition comprises propiconazole and dodecylamine or a 
dodecylamine salt. In the microbicidal composition, the propiconazole and 
the dodecylamine or dodecylamine salt are present in a synergistically 
effective amount to control the growth of at least one microorganism. This 
combination according to the invention achieves superior microbicidal 
activity at lower concentrations and lower cost than propiconazole alone 
against microbiological attack or degradation such as discussed above. 
Another embodiment of the present invention provides a method for 
controlling the growth of a microorganism on a substrate. This method 
comprises contacting the substrate with propiconazole and dodecylamine or 
a dodecylamine salt. The propiconazole and the dodecylamine or 
dodecylamine salt are present in a synergistically effective amount to 
control the growth of at least one microorganism on the substrate. 
Another embodiment of the invention provides a method for controlling the 
growth of microorganisms in an aqueous system capable of supporting growth 
of a microorganism. This method comprises the step of treating the aqueous 
system with propiconazole and dodecylamine or dodecylamine salt, where the 
propiconazole and the dodecylamine or dodecylamine salt are present in a 
synergistically effective amount to control the growth of at least one 
microorganism in the aqueous system. 
The combination of propiconazole and dodecylamine or a dodecylamine salt is 
useful in preventing the microbiological attack, degradation, or 
deterioration of various types of raw materials and products such as 
leather, textiles, pulp, paper and paperboard, coatings, lumber, as well 
as agricultural products such as seeds and crops. Advantageously, such a 
combination may be used in various industrial processes used to prepare or 
manufacture these products. Accordingly, additional embodiments of the 
present invention employ the combination to control the growth of 
microorganisms on or in such industrial products, raw materials or 
processes. 
The features and advantages of the present invention will be made more 
apparent from the following detailed description and preferred 
embodiments. 
DETAILED DESCRIPTION OF THE INVENTION 
As discussed above, the invention relates to combinations of propiconazole, 
also known as 
(RS)-1-2-(2,4-dichlorophenyl)-2-propyl-1,3-dioxalan-2ylmethyl!-1H-1,2,4-t 
riazole, with dodecylamine or a dodecylamine salt. Mixtures of dodecylamine 
and its salts may also be used. 
The dodecyl group of the dodecylamine or a dodecylamine salt may be 
branched or unbranched, i.e., straight chain. Preferably, the dodecyl 
group is unbranched. The dodecyl group may be unsubstituted or substituted 
by one or more substituents that do not adversely effect the activity of 
the inventive salts. Illustrative examples of suitable substituents 
include alkyl groups, alkenyl groups, alkoxy groups, aryl groups, aralkyl 
groups, hydroxy groups, oxo groups (to form a ketone), acid groups and 
derivatives thereof, such as esters and amides, and halogen atoms. 
Preferably, the dodecyl group is unsubstituted. 
The salts of dodecylamine employed in the present invention preferably have 
the following general formula: 
EQU C.sub.12 H.sub.25 NH.sub.3.sup.+ Z.sup.- 
in which Z is an anion or a fraction of a polyvalent counter ion sufficient 
to balance the cationic charge in the dodecylamine. The anion Z is 
preferably the conjugate base of an organic acid, i.e., Z is derived from 
an organic acid by loss of an ionizable proton. Illustrative examples of 
suitable organic acids are the mono- and di-carboxylic acids. 
Preferably, Z is derived from an acyclic, cyclic, or aromatic mono- or 
dicarboxylic acid. The carboxylic acid preferably has up to ten carbon 
atoms. If cyclic or aromatic, the ring may contain one or more 
heteroatoms, such as N, O, or S. The carboxylic acid may also be 
substituted by any suitable substituent that does not adversely effect the 
activity of the inventive compositions. Illustrative examples of suitable 
substituents include alkyl groups, substituted alkyl groups, alkenyl 
groups, substituted alkenyl groups, amino groups, oxo groups, halogen 
atoms, etc. 
Illustrative examples of useful carboxylic acid groups include: acetyl, 
propionyl, butyryl, citral, lactyl, valeryl, phthalyl, succinyl, octanoyl, 
nonanoyl, formyl, sorbyl, oxalyl, lauryl, cyclohexanoyl and benzoyl. One 
of ordinary skill will recognize that other organic acid groups may also 
be used in the present invention. 
One or more of the hydrogen atoms bound to the nitrogen atom may be 
replaced by a suitable substituent to give a secondary, tertiary, or 
quaternary amine salt of dodecylamine. Preferably, a primary amine salt of 
dodecylamine is employed. 
The following carboxylic acid salts of dodecylamine are particularly 
preferred in the practice of the present invention: dodecylamine acetate, 
dodecylamine maleate, dodecylamine malonate, dodecylamine propionate, 
dodecylamine butyrate, dodecylamine citrate, dodecylamine lactate, 
dodecylamine valerate, dodecylamine phthalate, dodecylamine succinate, 
dodecylamine hydroxysuccinate, dodecylamine octanoate, dodecylamine 
nonanate, dodecylamine formate, dodecylamine sorbate, dodecylamine 
oxalate, dodecylamine laurate, dodecylamine cyclohexanoate, dodecylamine 
benzoate, dodecylamine 2-hydroxybenzoate, dodecylamine 3-hydroxybenzoate, 
or dodecylamine 4-hydroxybenzoate. More particularly preferred of these 
compounds are dodecylamine acetate, dodecylamine propionate, and 
dodecylamine benzoate. 
The salts of dodecylamine are preferably prepared by reacting dodecylamine 
with the desired acid in the presence of a suitable solvent. Suitable 
acids groups are available in their acid or salt form either commercially 
from laboratory supply houses or can be prepared from readily available 
starting materials using well-known literature methods. The synthesis of 
the amine salts generally can be carried out in a solvent which may be a 
solvent for at least one of the reactants but which is generally a solvent 
for the desired product. Preferred solvent systems include inorganic acids 
and organic acids or alcohols. Most preferred is acetic acid. 
The reaction temperature may be readily determined by one skilled in the 
art depending on the particular reactants employed. Preferably the 
temperature of reaction varies from 40.degree. C. to 110.degree. C. or 
more, more preferably the temperature of the reaction is between 
70.degree. C. and 100.degree. C. The reaction is allowed to proceed until 
complete, as shown, for example, by a pH meter (the reaction is complete 
when the pH meter indicates that the limiting reactant has been 
neutralized). Generally, the reaction is stirred for 30 min to 2 hours, 
preferably for about 1 to 2 hours. 
After the reaction is complete, the reaction product can be worked up using 
well-known techniques to isolate and purify the desired salt of 
dodecylamine. Excess reactants and any solids formed during the reaction 
can be filtered off, and the filtrate evaporated to yield the crude 
product. In cases where the desired salt compound is a solid, the product 
of the reaction may be recrystallized from an appropriate solvent to yield 
a more pure compound. It should be noted, however, that both pure and 
crude salts of dodecylamine can be used for in the compositions and 
methods of this invention. The preparation of the dodecylamine salts is 
not limited to the exact process or steps described above. Any of 
procedures known to the art which yield the desired end product may be 
used. 
In one embodiment, the present invention relates to a microbicidal 
composition comprising propiconazole and dodecylamine or a dodecylamine 
salt. The propiconazole and the dodecylamine or dodecylamine salt are 
present in a synergistically effective amount to control the growth of at 
least one microorganism. 
Depending on the application, microbicidal compositions according to the 
present invention may be prepared in various forms known in the art. For 
example, the composition may be prepared in liquid form as an aqueous 
solution, dispersion, emulsion, or suspension, a dispersion or suspension 
in a non-solvent, or as a solution by dissolving the propiconazole and the 
dodecylamine or dodecylamine salt in a solvent or combination of solvents. 
Suitable solvents include, but are not limited to, methyl ethers of 
glycols, M-pyrol or petroleum distillates. The microbicidal composition 
may be prepared as a concentrate for dilution prior to its intended use. 
Common additives such as surfactants, emulsifiers, dispersants, and the 
like may be used as known in the art to increase the solubility of the 
propiconazole, dodecylamine, or dodecylamine salt in a liquid composition 
or system, such as an aqueous composition or system. In many cases, the 
biocidal composition of the invention may be solubilized by simple 
agitation. 
Microbicidal compositions of the present invention may also be prepared in 
solid form, for example as a powder or tablet, using means known in the 
art. In a preferred method of preparation, a liquid product containing 
propiconazole is deposited on a carrier such as diatomaceous earth 
zeolites, kaolin, or a water-soluable matrix and mixed with the 
dodecylamine or dodecylamine salt in the form of a liquid or solution to 
form a powder or tablet. 
The propiconazole and the dodecylamine or its salt may be combined in a 
single composition. Alternatively, the propiconazole and the dodecylamine 
or dodecylamine salt may be employed as separate components such that 
combined amount for the intended use is synergistically effective to 
control the growth of at least one microorganism. 
As mentioned above, a microbicidal composition of the invention 
demonstrates an unexpected enhanced microbicidal effect between the 
respective components, propiconazole and dodecylamine or a dodecylamine 
salt. That is, the combination according to the invention achieves 
superior microbicidal activity at lower concentrations to control the 
growth of microorganisms as compared to the microbicidal capability of 
either component alone. Thus, the combination synergistically enhances the 
microbicidal effect of the individual components. Such a superior effect 
presents a distinct economic advantage and increases the microbicide's 
effectiveness per unit weight. 
According to the present invention, control of the growth of a 
microorganism on a substrate or in an aqueous system means control to, at, 
or below a desired level and for a desired period of time for the 
particular substrate or system. This can vary from the complete prevention 
or inhibition of microbiological growth to control at a certain desired 
level and for a desired time. The combination of propiconazole with 
dodecylamine or a dodecylamine salt as described here can, in many cases, 
reduce the total microbiological count to undetectable limits and maintain 
the count at that level for a significant period of time. Accordingly, the 
combination may be used to preserve a substrate or system. 
The effective amount or percentage of the combination of propiconazole and 
dodecylamine or its salt acid necessary to achieve the desired result may 
vary somewhat depending on the substrate or aqueous system to be 
protected, the conditions for microbial growth, and the degree of 
protection desired. For a particular application, the amount of choice may 
be determined by routine testing of various amounts prior to treatment of 
the entire affected substrate or system. In general, an effective amount 
used on a substrate ranges from about 0.0001% to about 4% (w/w); 
preferably about 0.0001% to about 0.2%. With aqueous systems, an effective 
amount may range from about 0.5 to about 5000 parts per million, more 
preferably from about 5 to about 1000 parts per million of the aqueous 
system, and most preferably from, about 10 to about 25 parts per million. 
Similar amounts effectively control slime formation. For slime control, 
effective amounts preferably range from about 1 to about 200 parts per 
million, and more preferably, from about 1 to about 25 parts per million 
of the aqueous system. 
In a preferred embodiment, combinations of propiconazole and dodecylamine 
or a dodecylamine are those combinations having a weight ratio from about 
99:1 to about 1:99. More preferably the weight ratio is from about 60:10 
to about 10:60, and most preferably, from about 50:50 to about 25:75. The 
weight ratio may vary depending on the intended use, the microorganism 
encountered as well as the particular material, product, or system to 
which the combination according to the invention is applied. 
A combination of propiconazole with dodecylamine or a dodecylamine salt may 
be applied in a variety of industrial uses and processes for microorganism 
control. The combination of the invention may be used in place of and in 
the same manner as other microbicides traditionally used in the particular 
industry. As discussed above, such industries include, but are not limited 
to the leather industry, the lumber industry, the papermaking industry, 
the textile industry, the agricultural industry, and the coating industry. 
Combinations of propiconazole and dodecylamine or a dodecylamine salt may 
also be used with aqueous systems such as those previously discussed which 
are subject to microbiological attack and degradation. The problems caused 
by microbiological attack and deterioration in these various applications 
has been described above. The use of a combination according to the 
invention to control the growth of microorganisms in particular exemplary 
applications is described below. 
The invention also relates to a method for controlling the growth of 
microorganisms on various substrates. The method comprises the step of 
contacting a substrate susceptible to microbiological growth or attack 
with propiconazole and dodecylamine or a dodecylamine salt, as described 
above. The propiconazole and the dodecylamine or dodecylamine salt are 
present in a synergistically effective amount to control the growth of at 
least one microorganism on the substrate. Preferably, the method may be 
used to eliminate or prevent substantially all microbiological growth on 
the substrate. As discussed above, the components of a combination 
according to the invention may be applied together or as separate 
compositions. Preferred applications of this general method are discussed 
below. 
In the leather industry, a combination of propiconazole and dodecylamine or 
a dodecylamine salt may be used to control the growth of microorganisms on 
a hide during a tanning process. To achieve this control, the hide is 
contacted with a combined amount of propiconazole and dodecylamine or a 
dodecylamine salt synergistically effective to control the growth of at 
least one microorganism on the hide. The combination of the invention may 
be used in the tanning process in similar amounts and manner similar to 
that used to apply other microbicides used in the tanning industry. The 
type of hide may be any type of hide or skin that is tanned, for example 
cowhide, snake skin, alligator skin, sheep skin, and the like. The amount 
used, to some extent, will depend on the degree of microbiological 
resistance required and may be readily determined by one skilled in the 
art. 
A typical tanning process comprises a number of stages, including, but not 
limited to, a pickling stage, a chrome-tanning stage, a vegetable-tanning 
stage, a post-tan washing stage, a retanning stage, a dyeing stage, and a 
fatliquoring stage. The combination of propiconazole and dodecylamine or a 
dodecylamine salt may be used during all process stages in the tanning 
process in addition to those stages where a known microbiological problem 
is occurring. In each stage, the combination may be a component of the 
appropriate tanning liquor applied to the hide undergoing tanning. 
Incorporating the propiconazole and dodecylamine or a dodecylamine salt in 
a tanning liquor protects the hide from microbiological deterioration 
during the tanning process. Preferably, the combination is uniformly 
dispersed, e.g., under agitation, into an appropriate liquor to be used in 
a tanning process. Typical tanning liquors include, for example, a 
pickling liquor, a chrome-tanning liquor, a vegetable-tanning liquor, a 
post-tan washing liquor, a retanning liquor, a dye liquor, and a 
fatliquor. This method of application ensures that the combination applied 
to the hides protects against microbiological attack, deterioration, or 
other microbiological degradation. 
In a somewhat analogous nature, the combination of the invention may also 
be employed to control the growth of microorganisms on a textile substrate 
in a textile manufacturing process. Contacting the textile substrate with 
a synergistic combination of propiconazole and dodecylamine or a 
dodecylamine salt according to the invention effectively controls the 
growth of a microorganism on the textile substrate. In a textile process, 
the combination may be used in similar amounts and a manner similar to 
other microbicides commonly used in such processes. As one of ordinary 
skill would appreciate, particular amounts generally depend on the textile 
substrate and the degree of microbiological resistance required. 
The step of contacting the textile substrate with the combination of 
propiconazole and dodecylamine or a dodecylamine salt may be accomplished 
using means known in the textile art. To control microbiological growth, a 
textile process generally dips the textile substrate into a bath 
containing a microbicide, alone or with other chemicals used to treat the 
textile substrate. Alternatively, the textile substrate may be sprayed 
with a formulation containing a microbicide. In the bath or the spray, the 
propiconazole and dodecylamine or dodecylamine salt are present in a 
synergistically effective amount to control the growth of at least one 
microorganism on the textile substrate. Preferably, the bath and the spray 
are aqueous-based compositions. 
To preserve the value of its raw materials and products, the lumber 
industry also must control the growth of microorganisms in order to 
prevent microbiological degradation. A combination of propiconazole and 
dodecylamine or a dodecylamine salt according to the invention is 
effective to control the growth of microorganisms on lumber. 
A combination of propiconazole with dodecylamine or a dodecylamine salt may 
be used to protect the lumber in similar amounts and a similar manner 
employed for other microbicides used in the lumber industry. Contacting 
lumber with an effective amount of the combination may be accomplished, 
for example, by spraying the lumber with an aqueous formulation containing 
the combination, by dipping the lumber into a dip bath containing the 
combination, or other means known in the art. Dipping the lumber in an 
aqueous bath is preferred. 
The propiconazole and dodecylamine or dodecylamine salt are preferably 
uniformly dispersed in a bath (for example, by agitation) prior to the 
dipping of the lumber into the bath. In general, the lumber is dipped into 
the bath, raised, allowed to drip dry, and then air dried. The dip time 
will depend, as is known in the art, on a variety of factors such as the 
degree of microbiological resistance desired, the moisture content of the 
lumber, type and density of the wood, etc. Pressure may be applied to 
promote penetration of the combination into the lumber being treated. 
Applying a vacuum to the upper surface of the lumber may also be used to 
degas the lumber and promote increased wetting of the lumber by a bath 
containing the microbicidal combination. 
The combination of propiconazole and dodecylamine or dodecylamine salt 
according to the invention also has uses in the agricultural industry. To 
control the growth of microorganisms on a seed or plant, the seed or plant 
may be contacted with propiconazole and dodecylamine or a dodecylamine 
salt in a synergistically effective amount to control the growth of at 
least one microorganism on the seed or plant. This contacting step may be 
accomplished using means and amounts known in the agricultural industry 
for other microbicides. For example, the seed or plant may be sprayed with 
an aqueous formulation containing a combination of the invention or dipped 
into a bath containing the combination. After being sprayed or dipped, the 
seed or plant is generally dried by means known in the art such as drip 
drying, heated drying, or air drying. For plants or crops, the combination 
may also be applied using a soil drench. A soil drench is particularly 
advantageous when the microorganisms of concern inhabit the soil 
surrounding the plant. 
Yet another aspect of the present invention is a method for controlling the 
growth of microorganisms in an aqueous system capable of supporting such 
growth. The aqueous system is treated with propiconazole and dodecylamine 
or a dodecylamine salt such that the combination is present in an amount 
synergistically effective to control the growth of at least one 
microorganism in the aqueous system. This includes controlling, and 
preferably preventing, slime formation in the aqueous system. 
Examples of various aqueous systems include, but are not limited to, 
latexes, surfactants, dispersants, stabilizers, thickeners, adhesives, 
starches, waxes, proteins, emulsifying agents, cellulose products, aqueous 
emulsions, aqueous detergents, coating compositions, paint compositions, 
alum compositions, and resins formulated in aqueous solutions, emulsions 
or suspensions. The combination may also be employed in aqueous systems 
used in industrial processes such as metal working fluids, cooling waters 
(intake cooling water, effluent cooling water, and recirculating cooling 
water), waste waters including waste waters or sanitation waters 
undergoing treatment of the waste in the water, e.g. sewage treatment, and 
other recirculating water systems such as those used in papermaking or 
textile manufacture. 
As with the other uses discussed above, the combination of the invention 
may be used in the same amounts and in the same manner as microbicides 
traditionally used in these various aqueous systems. The combination may 
not only protect the aqueous system prior to use or when stored, but in 
many cases protects the aqueous system when in use or in appropriate 
applications even after the aqueous system has dried. When used in a paint 
formulation for example, the combination not only protects the paint in 
the can, but also the paint film after being applied to a substrate. 
Another embodiment of the present invention is a method for controlling the 
growth of microorganisms on paper or in a papermaking process, e.g., in a 
pulp or paper slurry and on a finished paper product such as paper board. 
The paper, pulp, or slurry is contacted with propiconazole and 
dodecylamine or a dodecylamine salt in a synergistically effective amount 
to control the growth of at least one microorganism on the paper, the pulp 
or in a slurry. The contacting step is accomplished using means and 
amounts known in the papermaking art. 
According to this aspect of the invention, for example, a forming web on a 
papermaking machine (or a wet-lap pulp) may be contacted with a 
combination according to the invention by spraying an aqueous dispersion 
containing the combination onto the pulp after the pulp leaves the presses 
in a papermaking process. Or, a combination of propiconazole with 
dodecylamine or a dodecylamine salt may be incorporated into a bath used 
at the wet or size press and the web contacted by nipping the web to 
incorporate the combination into the web with any other agents applied at 
the press. Alternatively, the pulp may be contacted by mixing 
propiconazole with dodecylamine or a dodecylamine salt into the pulp/white 
water mixture, preferably prior to the pulp reaching the formation wire. 
When treating paper (which includes paperboard and other cellulosic 
products or substrates), the propiconazole and dodecylamine or 
dodecylamine salt may be added into pulp slurries in the headbox, in the 
substrate forming solution, or in the white water system to treat the 
water system itself or for incorporation into the body of the paper. 
Alternatively, as with other known microbicides, a combination of the 
invention may be mixed into a coating used to coat the finished paper. 
As discussed above, the mode as well as the rates of application of the 
composition of this invention could vary depending upon the intended use. 
The composition could be applied by spraying or brushing onto the material 
or product. The material or product in question could be also treated by 
dipping in a suitable formulation of the composition. In a liquid or 
liquid-like medium, the composition could be added into the medium by 
pouring, or by metering with a suitable device so that a solution or a 
dispersion of the composition could be produced. 
The synergistic activity of combinations of propiconazole and dodecylamine 
or a salt of dodecylamine according to the invention has been confirmed 
using standard laboratory techniques as illustrated below. The following 
examples are intended to illustrate, not limit, the present invention.