Note: Descriptions are shown in the official language in which they were submitted.
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COMPOSITION INTENDED FOR THE PROTECTION
OF A SOLID SUBSTRATE AND ITS USE
BACKGROUND
The present invention concerns a composition that is
useful for protecting a solid substrate and its use.
It is common knowledge in protecting solid substrates
against environmental attack to use biocides for this
purpose. These compounds are agents that fight against or
kill plants or other undesirable living organisms. The
problem with the use of biocides is that they are very
often water soluble and, as such, when exposed to bad
weather, for example in the form of rains or floods, they
will be diluted or washed out, with the result that the
treated substrate is deprived of the protection of the
compound. Thus, there is a need for improvements in this
area so that biocide treated substrates can retain their
effectiveness even under wet conditions.
SUMMARY OF THE INVENTION
The invention relates to a substrate treating
composition for the protection of a solid substrate against
environmental attack. This composition comprises at least
one biocidal component, a hydrophobing agent, and a solvent
for maintaining the components) and agent in a liquid
phase. The biocidal component is present in an amount
sufficient to retard growth or kill plants or similar
living organisms while the hydrophobing agent is present in
an amount effective to impart hydrophobicity to, or
increase the hydrophobicity of, the substrate after the
liquid composition is applied thereto.
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Advantageously, the hydrophobing agent is a C1 to C4
alkyl siliconate compound or a siloxane polymer. A
preferred siloxane polymer is a polydimethyl(H)siloxane.
The alkyl siliconate compound may be an alkali metal
methyl siliconate present in an amount of about 0.005 to
5 % by weight. Preferably, the alkyl siliconate compound
is a sodium or potassium methyl siliconate and is present
in an amount of about 0.1 to 2 % by weight. If desired, a
portion of the alkyl siliconate compound can be replaced
with a silicate compound. This reduces the cost of the
composition and improves performance as well.
The biocidal component of the composition is
preferably a fungicide, an algicide, an insecticide, a
rodenticide, a herbicide, a bactericide, or mixtures
thereof. Generally, the biocidal component is present in
an amount of about 100 to 10000 ppm.
The solvent is preferably water or an alcohol/water
mixture.
The invention also relates to a method of treating a
substrate which comprises applying one of the solutions of
the invention upon or within the substrate to retard growth
or kill plants or similar living organisms on or in the
substrate and to impart hydrophobicity to, or increase the
hydrophobicity of, at least a portion of the substrate and
to impart or to render hydrophobic a portion of the
substrate after the liquid composition is applied thereto.
The composition is typically applied to the substrate by
topical application or by immersion.
Any of a wide variety of substrates can be treated
according to the invention. Rock, stone, a stone-like
material, a cement, a concrete or mixtures thereof, a wood,
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a textile, grains or cellulose-based products are all
suitable for treatment.
DETAILED DESCRIPTION OF THE PFRERRED EMBODIMENTS
The present invention relates to the development of a
composition for the treatment of a solid substrate which,
even exposed to bad weather as described above, will
conserve its biocidal protection of the substrate. A
further benefit of such a composition, according to the
invention, is to provide a durable protection of the
substrate.
The composition of the present invention is capable of
protecting a substrate against all environmental attacks.
The solid substrate that is to be treated with the
composition of the invention can be of all types that, when
exposed to bad weather, may be subject to environmental
attacks and/or attacks from rodents. For example, the
nature of the substrate may be stone-like, wood, textile,
or may be grains or cellulose-based products. Stone-like
materials in the present description include tiles,
concrete structures, bricks, sandstone and other porous
stones, earthenware objects and the like. Wood, in the
present description, includes construction materials (e. g.,
oak, beech, pine) and decorative wood (e. g., special woods
for works of art, statues, furniture). Textiles include,
for example, jute sacks used to contain raw materials such
as coffee, cocoa, cereals or other food products. Grains
include all kinds of grains attacked by rodents.
Cellulose-based products include paper, paperboard and
cardboard.
The hydrophobing agent is chosen among the group
constituted by an alkylsiliconate compound and a siloxane
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polymer: When using the alkyl siliconate compound, the
solvent in the composition is preferably water, while when
using the siloxane polymer, the solvent is preferably an
alcohol/water mixture, such as methanol/water or
ethanol/water. The alkyl siliconate is preferentially
methyl siliconate. The siloxane polymer is by preference
polydimethyl(H)siloxane.
When an alkyl siliconate compound is utilized, part of
that compound can be replaced by a silicate compound.
These compounds are present in combination in amount
effective to increase the hydrophobicity of the substrate
after the solution is applied thereto. Advantageously, the
siliconate compound is an alkali metal alkyl siliconate and
the silicate compound is an alkali metal silicate, with the
silicate and siliconate compounds being present in a molar
ratio of about 0.5:1 to 10:1. Preferably, the siliconate
compound is a alkali metal methyl siliconate and the
silicate compound is an sodium or potassium hydrosoluble
silicate, with the silicate and siliconate compounds being
present in a molar ratio of about 1:1 to 5:1. The most
preferred siliconate compound is a sodium or potassium
methyl siliconate and the most preferred silicate compound
is an sodium or potassium ortho or meta-silicate, with the
most preferred molar ratio being about 2:1 to 3:1. In
these mixtures, the siliconate compound is typically
present in an amount of about 0.1 and 1% by weight and the
silicate compound is typically present in an amount of
about 0.01 and 5% by weight.
Depending on the end use of the composition according
to the invention, different types of biocides can be
included, either alone or in mixtures. The biocides are
chosen among the group constituted by a fungicide, an
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algicide, an insecticide, a rodenticide, a herbicide and a
bactericide.
The type of biocide is selected based upon the type of
substrate to be protected. To protect a stone-like
5 substrate, for example, the composition according to the
invention advantageously contains a fungicide as biocidal
agent. Preferred fungicides in the present invention
include sodium or potassium sorbate and the copper complex
of ethylene diamine tetra-acetate (EDTA), these compounds
being present in the composition alone or in combination.
In this case, a preferred hydrophobing agent is sodium or
potassium methylsiliconate in aqueous solution.
In contrast, to protect a wooden substrate, the
composition according to the invention contains an
insecticide and/or a fungicide. The insecticide is
preferably chosen from the group consisting of salts and
chelates of active metals (Cu, Cr, Hg), fluorides,
rotenoide, pyrethoides, nitrophenols or the usual chlorine
derivatives such as DDT. In this case, the hydrophobing
agent is preferably polydimethyl(H)siloxane in a
methanol/water solvent.
To protect textiles, for example jute cloth, against
rodents, one employs a mixture of a rodenticide, such as
coumarin, with polydimethyl(H)siloxane as the preferred
hydrophobing agent and a methanol/water solvent.
To treat grains against rodents, one employs a
rodenticide with polydimethyl(H)siloxane as the preferred
hydrophobing agent.
To treat cellulose-based products, one employs a
fungicide and/or a rodenticide, with
polydimethyl(H)siloxane or a methylsiliconate compound as
the hydrophobing agent.
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The present invention also concerns the utilization of
the aforementioned composition, such as by applying it to
the substrate by topical application or by immersion. It
is preferable to package the composition according to the
invention in a concentrated form and then to dilute it
appropriately before use so as to avoid excessive transport
costs of the composition.
The composition according to the invention, when ready
for use, is diluted to contain on the order of 0.005 to 5
by weight of the hydrophobing agent, with a preference for
0.1 to 2 %, along with about 100 to 10000 ppm of the
biocidal component. The diluted composition described is
applied ideally at a rate of 1 1 for each 10 m2 of the
surface to be treated. As the composition is in liquid
form, it enables the hydrophobing agents to penetrate in
normal conditions to a depth on the order of about 1 to
10 mm into wood or stone-like materials, which guarantees a
good and durable protection of the treated substrate.
EXAMPLES
The rest of the description is given by reference to
the following specific examples which illustrate the most
preferred embodiments of the invention.
Example 1 Treatment of stone-like materials
25.3 kg of potassium sorbate is dissolved in 50 kg hot
water. Then, to a suspension of EDTA and copper sulfate in
10 L water, 3 kg of sodium hydroxide is progressively added
while simultaneously cooling the mixture. The solutions
containing sorbate and complexed copper are then mixed, and
the volume adjusted to 100 L by adding water. The
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resulting solution is mixed with 1000 kg of technical grade
potassium methylsiliconate from Rhone Poulenc.
This preparation is diluted in water by a factor of 50
and applied by spraying on sandstone. After drying and
S reaction, the treated surface is compared to a non-treated
surface as reference, after a season of exposure to the
elements. The non-treated surface is humid and colonized
by moss and/or lichens and or other vegetal species,
whereas the treated surface exposed to the same conditions
is visibly dry and free of vegetal colonization.
Example 2 Treatment of stone-like materials
Example 1 is repeated, except that the sorbate and
complexed copper solution is mixed with 500 kg of technical
grade potassium methylsiliconate from Rhone Poulenc and
500 Kg of potassium meta silicate.
This preparation is diluted in water by a factor of 50
and applied by spraying on sandstone. After drying and
reaction, the treated surface is compared to the surface
treated according to Example 1 as well as to the non-
treated, reference surface, after a season of exposure to
the elements. The treated surface of Example 2, like that
of Example 1, is visibly dry and free of vegetal
colonization.
Example 3 Treatment of wood
In 1L of an emulsion of technical grade
polydimethyl(H)siloxane from Rhone Poulenc, 10 g of sodium
fluoride, 20 g of copper complex and 0.1 g of allethrin
(synthetic pyrethroid) are dissolved. A solution of 10 g
lindane in 0.1 L methanol is prepared, and then is added
under agitation to the aqueous phase previously prepared.
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An aqueous dilution at 2% of the above preparation is
used for the following tests:
Four samples each of oak, beech and pine woods,
dimensions 10 mm/50 mm/50 mm are soaked to saturation at
the dilution described.
After drying, the samples exhibit the desired
hydrophobic characteristics. They are placed, along with
reference samples of untreated woods, on a surface of wood
compost infested with wood louse (coleoptera) larvae and
lichen spores, in a container kept at a temperature of 30°C
and with water added frequently to maintain a high
humidity.
Over a 3 month period, a perfect conservation, with
neither alteration nor discoloration, is observed on the
treated samples, whereas all of the non-treated reference
samples already show a marked degradation (although less
visible for oak wood than the others) and a pronounced
darkening in color.
