U.S. patent application number 10/131134 was filed with the patent office on 2002-11-07 for biocidal plastic material.
This patent application is currently assigned to NovaPharm Research (Australia) Pty Ltd.. Invention is credited to Kritzler, Steven, Kwon, Hyo Sang.
Application Number | 20020165112 10/131134 |
Document ID | / |
Family ID | 3804889 |
Filed Date | 2002-11-07 |
United States Patent
Application |
20020165112 |
Kind Code |
A1 |
Kwon, Hyo Sang ; et
al. |
November 7, 2002 |
Biocidal plastic material
Abstract
The invention provides a biocidal concentrate including zinc
pyridinethione; and a second biocide selected to be biocidally
effective in a pH range complimentary to zinc pyridinethione. The
second biocide may be an aromatic halogenated phenol such as
triclosan, dichlorophen and trichlorcarban. The invention also
provides biocidal cleaning devices and plastic materials and
methods of manufacture thereof.
Inventors: |
Kwon, Hyo Sang; (Rosebery,
AU) ; Kritzler, Steven; (Rosebery, AU) |
Correspondence
Address: |
LEYDIG VOIT & MAYER, LTD
700 THIRTEENTH ST. NW
SUITE 300
WASHINGTON
DC
20005-3960
US
|
Assignee: |
NovaPharm Research (Australia) Pty
Ltd.
Rosebery
AU
NSW 2018
|
Family ID: |
3804889 |
Appl. No.: |
10/131134 |
Filed: |
April 25, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10131134 |
Apr 25, 2002 |
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09555269 |
Aug 4, 2000 |
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6399560 |
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09555269 |
Aug 4, 2000 |
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PCT/AU98/00984 |
Nov 26, 1998 |
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Current U.S.
Class: |
510/382 ;
510/383; 510/499 |
Current CPC
Class: |
A01N 2300/00 20130101;
A01N 43/40 20130101; A01N 43/40 20130101; A61L 2/18 20130101 |
Class at
Publication: |
510/382 ;
510/383; 510/499 |
International
Class: |
C11D 003/48 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 27, 1997 |
AU |
PP 0605 |
Claims
The claims of the present invention are as follows:
1. A biocidal concentrate comprising: a first biocide which is a
metal pyridinethione; and: a second biocide selected to be
biocidally effective in a pH range complementary to said metal
pyridinethione, said second biocide selected from the group
consisting of: halogenated phenols, phenols, derivatives of
halogenated phenols, derivatives of phenols, and
trichlorcarbon.
2. A biocidal concentrate according to claim 1 wherein said
metallo-pyridinethione is zinc pyridinethione.
3. A biocidal concentrate according to claim 1 wherein said
metallo-pyridinethione is sodium pyridinethione.
4. A biocidal concentrate according to claim 1 wherein said
metallo-pyridinethione is magnesium pyridinethione.
5. A biocidal concentrate according to any one of claims 1 to 4
wherein the second biocide is dichlorophen.
6. A biocidal concentrate according to any one of claims 1 to 4
wherein the second biocide is triclosan.
7. A biocidal concentrate according to any one of the preceding
clam wherein the metal pyridinethione comprises 5-25% w/w of the
mixture.
8. A biocidal concentrate according to any one of the preceding
claims wherein the metal pyridinethione comprises 11-16% w/w of the
mixture.
9. A biocidal concentrate according to any one of the preceding
claims wherein the second biocide comprises 32-37% of the
mixture.
10. A biocidal concentrate according to any one of the preceding
claims wherein the second biocide comprises 25-45% w/w of the
mire.
11. A biocidal concentrate according to any one of the preceding
claims further including a mineral oil.
12. A biocidal concentrate according to any one of the preceding
claims further including polyvinlypyrrolidone.
13. A biocidal concentrate according to any one of the preceding
claims further including an alcoholic solvent.
14. A biocidal concentrate according to any one of the preceding
claims further including water.
15. A biocidal clean device comprising: A biocidal concentrate
according to any one of claims 1 to 14; and a substrate.
16. A biocidal cleaning device according to claim 15 wherein the
metal pyridine thione is present in an amount of to 2.5% of the
weight of the device.
17. A biocidal cleaning device according to claim 15 or 16 wherein
the metal pyridine thione is present in an amount of 0.05-10% of
the weight of the device.
18. A biocidal cleaning device according to any one of claims 15-17
wherein the metal pyridine thione is present in an amount of
0.1-1.0% of the weight of the device.
19. A biocidal cleaning device according to any one of claims 15-18
wherein the second biocide is present in an amount up to 6% of the
weight of the device.
20. A biocidal device according to any one of claims 15-19 wherein
the second biocide is present in an amount of 0.05-2.0% of the
weight of the device.
21. A biocidal cleaning device according to any one of claims 15-20
wherein the second biocide is present im an amount of 0.1-2.0% of
the weight of the device.
22. A biocidal cleaning device according to any one of claims 15-21
wherein the substrate is cloth.
23. A biocidal cleaning device according to claim 22 wherein the
cloth weight is from 30-200 g/m.sup.2.
24. A biocidal cleaning device according to claim 22 or 23 wherein
the cloth weight is from 30-120 g/m.sup.2.
25. A biocidal cleaning device according to any one of claim 22-24
wherein the cloth is comprised of from: 70-100% rayon; and 0-30%
polyester.
26. A biocidal cleaning device according to claim 25 comprising
0-30% polypropylene.
27. A biocidal cleaning device according to any one of claims 15-21
wherein the substrate is sponge or a synthetic equivalent.
28. A biocidal cleaning device according to any one of claims 15-21
wherein the substrate is paper.
29. A biocidal cleaning device according to any one of claims 15-21
wherein the substrate is woven textile.
30. A method of making a biocidal cleaning device comprising the
steps of: combining a biocidal concentrate according to any one of
claims 1 to 14 with a binding agent; contacting the resultant
formulation with a substrate; and binding the formulation to the
substrate with binding means.
31. A method according to claim 30 wherein said binding means is in
the form of a heat treatment.
32. A method of making a biocidal cleaning device according to
claim 31 wherein the heat treatment is carried out by a steam
heated drum.
33. A method of making a biocidal cleaning device according to
claim 31 wherein the heat treatment is applied by infra red
means.
34. A method according to claim 30 wherein said binding means is in
the form of UV or visible light.
35. A method of making a biocidal cleaning device according to any
one of claims 30-34 wherein the binding agent is a polymer latex
formulation.
36. A method of making a biocidal cleaning device according to any
one of claims 30-34 wherein the big agent is acrylate.
37. A method of making a biocidal cleaning device according to any
one of claims 30-36, wherein the substrate is selected from the
group comprising cloth, sponge or a synthetic equivalent, paper and
woven textiles.
38. A method of making a biocidal cleaning device according to any
one of claims 30-37 wherein the absorbent material is cloth.
39. Biocidal plastic material incorporating a biocidal concentrate
according to any one of claims 1-14.
40. A method of making a biocidal plastic material comprising the
steps of: a) dissolving a biocidal mixture according to any one of
claims 1-14 in a plasticiser; b) compounding the above formed
biocide-plasticiser mixture into a polymer; and c) forming the
plastic into the deed shape.
41. A method of making a biocidal plastic material according to
claim 40 wherein the plasticiser is a hydrocarbon.
42. A method of making a biocidal plastic material according to
claim 41 wherein the plasticiser is selected from the group
comprising polybutene, low density polyethylene, low density
polypropylene and paraffin wax.
43. A method of making a biocidal plastic material according to
claim 40 wherein the plasticiser is an ester.
44. A method of making a biocidal plastic material according to
claim 43 wherein the plasticiser is selected from the group
comprising dibutyl phthalate and dioctylphthalate.
45. A method of making a biocidal plastic material according to
claim 43 wherein the plasticiser is an epoxidised vegetable oil or
a blend thereof.
46. A biocidal concentrate substantially as herein described with
reference to any one of the examples.
47. A biocidal cleaning substantially herein described with
reference to any one of the examples.
48. A method of making a biocidal cleaning device substantially as
herein described with reference to any one of the examples.
49. A biocidal plastic material substantially as herein described
with reference to any one of the examples.
50. A method of making a biocidal plastic material substantially as
herein described with reference to any one of the examples.
Description
TECHNICAL FIELD
[0001] This invention relates to a biocidal cleaning composition
and the incorporation thereof into a biocidal cloth, sponge, paper,
wound dressing, plastic or other substrate.
BACKGROUND ART
[0002] In domestic and hospital environments one of the most common
methods of cleaning large surfaces is to wipe a cloth over such
surfaces. Typically, the cloth will be moistened with water and may
additionally have added a detergent or disinfectant. Cloths which
do not contain a disinfectant are ineffective in controlling the
growth of microorganisms. Indeed, the cloth itself may provide
favourable conditions for the proliferation of such microorganisms
and the action of wiping such an infected cloth over a surface may
produce an effect counter to the desired outcome of making the
surface more hygienic. Ordinary cleaning cloths which remain damp
for a period are also notorious for the odours they develop, which
are a result of microbial action.
[0003] Soaking a cloth in disinfectant provides fairly short term
relief and requires the reapplication of the disinfectant to the
cloth. While this method uses only modest amounts of disinfectant,
the quantity is nevertheless much more than is required to achieve
adequate bactericidal action. An extremely efficacious disinfectant
is also required to prevent bacterial proliferation in the cleaning
cloth itself, especially against the wide range of bacteria which
are present in domestic and hospital situations. This somewhat
unsophisticated method is also wasteful in that every time the
cloth is rinsed or washed the disinfectant is removed and a new
aliquot must be applied.
[0004] It has been practiced to incorporate an antimicrobial agen
in a non-woven fabric as a colloidal suspension within an amorphous
polymeric binder. The antimicrobial is not bound and is available
to migrate to the surface of the binding agent. Such systems
require an internal reservoir having a very large quantity of
antimicrobial agent--typically 12 to 30 grams per square yard, and
are more costly and less durable than is desired.
[0005] Cellulose sponges containing zinc pyridinethione as an
active antibacterial agent are known. These sponges suffer from the
drawback that a single wash in a washing machine is sufficient to
remove much of the zinc pyridinethione. Thus, the sponge remains an
effective weapon against bacteria for only a limited portion of
its' working life, and may lead to users having false confidence in
its' potency.
[0006] The reason that the zinc pyridinethione is so readily
removed under normal washing conditions is that it is hydrolysed
markedly at around pH 11. Zinc pyridinethione is an effective
biocide, but suffers from the drawback that its optimal range of
efficacy is within the pH range of 4.5 to 9.5. Many detergents and
household cleaning agents have pH's above this range (for instance
washing powders give rise to solutions of around pH 11 and
household bleaches have a pH of around 13), and, as in use they are
often present in greater quantities than the zinc pyridinethione,
are capable of rendering it ineffective.
[0007] The use of high concentrations of zinc pyridinethione to
compensate for it's high loss under domestic cleaning conditions is
undesirable as it has some human toxicity and is mildly irritating
to the skin, and severely so to the eye. Further, the zinc
pyridinethione has been shown to leach irreversibly out of the
sponge over time.
[0008] There remains the problem then of providing a cleaning
device, such as a cloth, sponge or similar, which will remain
effective against a wide range of bacteria for a significant period
of time, yet will not be unacceptably toxic.
[0009] Surprisingly, the inventor has found that one or more
selected biocides, for example triclosan, dichlorophen (sometimes
known as "dichlorophen" or DCP) or other chlorinated phenolic
biocides, phenolic biocides, or trichlorcarban, in combination with
an organometallic biocide, for example a metallic pyridinethione
exhibit a synergy which enables the combination to be effective
against a wide range of bacteria under a wide range of pH
conditions. Further, the addition of an acrylate binder, with or
without other immobilising agents such as PVP, has also been found
to render the biocidal mixture suitable for incorporation into a
substrate for example a woven or non-woven cloth.
[0010] It is to be appreciated that such a biocide and method of
binding is not limited to textiles used for cleaning, but may also
be applicable to other materials, such as sponges, paper, wound
dressings, plastics or even concrete.
DESCRIPTION OF THE INVENTION
[0011] It is to be understood that the use of the term "biocidal"
throughout this specification is used in the sense that it refers
to killing one or more organisms, and thus it embraces both the
terms "biocidal" and "biostatic" as commonly referred to in
relation to reducing or maintaining the number of microorganism in
a colony.
[0012] According to a first aspect the invention consists in a
biocidal composition comprising a first biocide which is a metal
pyridinethione; and a second biocide selected to be biocidally
effective in a pH range complementary to the metal pyridinethione,
said second biocide selected from the group consisting of
halogenated phenols, phenols, derivatives of halogenated phenols,
derivatives of phenols and trichlorcarban
[0013] Examples of derivatives include diphenyl ether derivatives,
methylene bridged derivatives and the like. The most preferred
compounds are triclosan, dichlorophen and trichlorcarban. Examples
of phenolic biocides which may be used include, but are not limited
to, ortho-phenylphenol, methyl parahydroxybenzoate, propyl
parahydroxybenzoate, ortho-cresol, meta-cresol and para-cresol.
[0014] Preferably the metal pyridinethione is zinc, sodium or
magnesium pyridinethione, and most preferably it is zinc
pyridinethione.
[0015] According to a second aspect the invention consists in a
biocidal cleaning device comprising a biocidal composition
according to the first aspect and a substrate.
[0016] According to a third aspect the invention consist a method
of making a biocidal cleaning device comprising the steps of
combining a biocidal composition according to the firs aspect with
a binding agent and contacting the resultant formulation with a
substrate. Preferably the method further includes the step of
binding the composition to the substrate.
[0017] According to a fourth aspect, the invention consists in a
biocidal plastic material comprising a biocidal composition
according to the fist aspect
[0018] According to a fifth aspect, the invention consists in a
method of making a biocidal plastic material according to the
fourth aspect comprising the steps of dissolving a biocidal
composition according to the first aspect in a plasticiser then
compounding the plasticiser into a polymer and forming the polymer
into a desired shape.
[0019] Preferably in a biocidal cleaning device the metal
pyridinethione is present in amounts up to 2.5% of the Weight of
the device. More preferably it is present in amounts of 0.05 to
1.0% of the weight of the device. Most preferably it is present in
amounts of 0.1 to 1.0% of the Weight of the device.
[0020] Preferably in the biocidal cleaning device the second
biocide is present in amounts up to 6% of the weight of the device.
More preferably it is present in amounts of 0.05 to 2.0% of the
weight of the device. Most preferably it is present in amounts of
0.1 to 2.0% of the weight of the device.
[0021] Desirably the biocidal composition is prepared as a
concentrate which is diluted prior to impregnation into the
substrate. In the concentrate the metal pyridinethione is present
in amounts up to 40% w/w. and more preferably 20 to 30% w/w.
[0022] Preferably the second biocide is present in the biocidal
concentrate in amounts up to 60% w/w, and more preferably 20 to 40%
w/w.
[0023] The biocidal composition or concentrate may also include, in
any combination, a mineral oil. (PVP) polyvinylpyrrolidone, an
alcoholic solvent, an anionic surfactant, a non-ionic surfactant
and water.
[0024] The substrate for use in the biocidal cleaning device is
preferably cloth.
[0025] Preferably the cloth weight is from 30 to 200 g/m.sup.2, and
more preferably from 30-120 g/m.sup.2 and the cloth is comprised of
from: 70-100% rayon and 0-30% polyester. Preferably, the cloth also
includes 0-30% polypropylene.
[0026] The substrate may also be sponge or a synthetic equivalent,
paper or woven textile. In the case of a sponge, the weight can be
up to 250 g/m.sup.2 or more.
[0027] When binding the biocidal mixture onto a substrate
preferably the binding means comprises a heat activated
crosslinking reaction. The heat activated crosslinking reaction may
be carried out by a steam heated drum or by infra red means. The
crosslinking reaction may also be activated by UV or visible light,
electron beam or the like or chemical initiation.
[0028] The binding agent used in binding a biocidal mixture to a
substrate may be a polymer latex formulation or acrylate, in
particular acrylate copolymers.
[0029] When making a biocidal plastic material the plasticiser is
optionally a hydrocarbon, preferably selected from the group
comprising polybutene, low density polyethylene, low density
polypropylene and paraffin wax. The plasticiser may also be, for
example, an ester preferably selected from the group comprising
dibutyl phthalate. dioctylphthalate, or epoxidised vegetable oil or
blends thereof.
[0030] Unless the context clearly requires otherwise, throughout
the description and the claims, the words comprise, comprising, and
the like are to be construed in an inclusive sense as opposed to an
exclusive or exhaustive sense that is to say, in the sense of
including, but not limited to.
BEST MODE FOR CARRYING OUT THE INVENTION
[0031] Preferred embodiments of the invention will now be described
by way of example only. In the embodiments described zinc
pyridinethione is used as the first biocide and triclosan as the
second. However it will be understood that the invention is not
limited to this embodiment.
[0032] The combination of zinc pyridinethione and triclosan or
dichlorophen provides important advantages over the use of either
disinfectant alone.
[0033] Zinc pyridinethione is effective at pH ranges from 4.5 to
9.5. As many detergents are strongly basic in nature, they can
render zinc pyridinethione ineffective at very high pH's.
Triclosan, dichlorophen, trichlorcarban, chlorinated phenolic
biocides and phenolic biocides generally, on the other hand become
more effective at higher pH ranges, in particular, at pH 9.5 and
above.
[0034] In pH neutral or near neutral conditions, i.e. in the
absence of large amounts of detergent, both the zinc pyridinethione
and the complementary biocide work well. However, zinc
pyridinethione, while effective against gram positive
microorganisms, has been shown to be intrinsically only of limited
effectiveness against gram negative bacteria, Triclosan and
dichlorophen, for example, on the other hand while having some gram
negative activity are particularly effective against gram positive
bacteria. In particular, the combination of the zinc pyridinethione
and the complementary biocide as described above, has been shown to
exhibit a marked synergistic effect in killing Pseudomonas
Aeruginosa.
[0035] The quantity of zinc pyridinethione used in the mixture to
achieve a given bactericidal result is much less than if it was
used alone, with the added advantage that less of this relatively
toxic compound is used.
[0036] Thus, the combination of the two active ingredients is
effective against a wide range of microorganisms at neutral pH's,
and retains a good deal of this efficacy at higher pH's, in the
presence of detergents.
[0037] The compositions of the present invention may also be used
against mould.
[0038] Toxicologically, DCP is much safer than Zinc pyridinethione.
Toxicological data is shown in table 1. It is possible to formulate
a biocidal mixture which has a high biocidal activity over a wide
pH range, against a broad spectrum of microorganisms yet exhibiting
with a low level of toxicity to humans.
1TABLE I PROPERTY DICHLOROPHEN ZINC PYRIDINETHIONE Melting Point
.degree. C. 175 240 Decomp. .degree. C. 290 240 pH Stability
>activity>pH decomposes pH>9.5 Oxidising Agents
incompatible decomposes Reducing Agents no effect decomposes
Biodegradability Yes No Acute Toxicity LD50 Oral 3300 mg/kg 160
mg/kg LD50 Dermal 5000 mg/kg 100 mg/kg LD50 Subcut >3000 mg/kg
730 mg/kg LD50 IV 17 mg/kg 10 mg/kg Teratogenicity no effect
reduced wt Fish Toxicity 23 mg/lt not available Irritancy Slight
dermal Moderate dermal Moderate eye Severe eye Genotoxicity None
None Regulatory: Max 0.1 mg/lt Max 0.1 mg/lt Pesticide in waste
water in waste water Heavy Metal none Max 10 mg/lt
[0039] PVP (poly vinyl pyrrolidone) may be added optionally as a
complexing material. PVP modifies the solubility and dispersibility
of the biocide in water, as disclosed in PCT/AU96/00224.
[0040] The ability of PVP to modify the solubility and
dispersibility have been found extremely useful when incorporating
composite biocidal mixtures of the present invention onto a
substrate, for example, cloth.
[0041] It is postulated that the PVP and the second (non-zinc
pyridinethione) biocidal compound form a complex which provides
excellent binding between the cloth and the active ingredients,
retaining the biocidal dispersion and providing a longer effective
life to for the biocidal cloth. A postulated complex is shown in
FIG. I. It will be appreciated that the dichlorophen need not be
complexed with a single polymeric strand of the PVP, but may
cross-link one or more other strands. FIG. I. The structure of the
complex formed between Dichlorophen and PVP 1
[0042] Preferably for disinfecting and cleaning,
polyvinylpyrrolidones with a degree of polymerisation (K value) of
15, 30, 60 and 90, most preferably 90 or copolymers with
vinylacetate comprising from 20 to 80% polyvinylpyrrolidone (most
preferably comprising at least 50% vinylacetate and can possibly
possess cationic character) are used.
[0043] For impregnation, the amount of PVP polymer used is
preferably in the range of from 0.01 to 99.9 parts of the polymer
for each part of biocide. More preferably the polymer is in the
range of from 0.01 to 50 parts and most preferably 0.01 to 10 parts
for each part of phenolic biocide.
[0044] The triclosan. DCP, trichlorocarban or other complementary
biocide can at any time be substituted by a PVP/DCP, PVP/triclosan,
PVP/trichlorocarban of PVP/complementary biocide combination.
[0045] The addition of a binding agent such as an acrylate enhances
binding of the biocide into a woven or non-woven textile. The
addition of polyvinylpyrrolidone has also been found to increase
the binding of the biocidal agents to the cloth, either alone or in
combination with the acrylate binder. More importantly, the
addition of polyvinylpyrrolidone has been found to limit the
biocide, so that as the surface wears. fresh biocide is exposed at
the fresh surface.
[0046] The biocidal mixture in any of its forms can be mixed into
binders such as acrylic or acrylic copolymer lattices or solutions.
PVA lattices or PVA copolymer lattices or solutions, or any other
polymer latex or solution or blend of any of the previously
described polymers.
[0047] The biocidal mixture, with or without PVP or binding agents
can be used for the treatment of any type of substrate, including
woven or non-woven textile, fabrics, sponges, scourers and the
like, paper, or any other material. The treatments can be applied
from solutions, suspensions or emulsions at ambient or other
operational temperatures.
[0048] The inclusion of a mineral oil and an acrylate binder into
the any of the above formulation can increase the suitability of
the biocidal mixture for cloth impregnation.
[0049] The most suitable fabrics for impregnation with the biocidal
mixture are those which are rayon/polyester cloths which contain
from 70 to 100 percent rayon, although most known fabrics perform
adequately. In particular, fabrics which weigh between 30 and 200
g/m.sup.2 and especially 30 and 120 g/m.sup.2 have been found to be
the most suitable.
[0050] Plasticisers are commonly added to synthetic polymers to
modify their hardness and/or flexibility. Some common plasticisers
are hydrocarbon polymers, such as polybutene, low density
polyethylene, low density polypropylene and paraffin wax. Other
commonly used plasticisers are esters, such as dibutyl phthalate,
dioctyl phthalate and similar esters, such as epoxidised vegetable
oils or blends thereof and similar esters.
[0051] The biocide combination can be dissolved into a plasticiser
or plasticisers and then compounded into a polymer which is then
moulded by extrusion, injection moulding or some other process. The
resulting item would then resist the growth of microorganisms on
the surface of the item by virtue of the incorporated biocides. If
the plasticiser were selected so as to be incompatible with the
bulk material, it leaches out slowly, carrying effective amounts of
the biocidal composition with it to the surface.
[0052] A use of particular interest is on materials used in
evaporative cooling systems. Such systems typically harbour a wide
range of bacterial varieties, including legionella. The use of a
bound bactericide in such systems would provide a low but long
lasting level of activity against bacteria. Such systems typically
utilise a number of plastic plates, and impregnating these with a
biocidal mixture and a binder which was incompatible with the
plastic, so as to leach slowly to the surface, would provide a
constantly self renewable biocidally active surface.
EXAMPLES
[0053]
2 Raw Material % W/W Example 1. Formulation of Biocidal Concentrate
The following formulation is prepared: Zinc Pyridinethione 17.19
Dichlorophen 34.39 Mineral Oil 22.92 PVP 8.44 Ethanol 3.44 Sodium
Lauryl Ether Sulfate 0.70 Dioctyl Sulfosuccinate 1.50 Water qs 100%
Example 2: Alternate Biocidal Concentrate Zinc pyridinethione 24.60
Dichlorophen 24.60 Mineral Oil 16.40 PVP 7.20 Ethanol 2.40 Sodium
Laurylether sulfate 0.70 Dioctyl Sulfosuccinate 1.50 Water qs 100%
Example 3. Binder Formulation Acrylic polymer self crosslinking
46.0 binder emulsion (approx 56% solids) Defoamer emulsion 0.15
(Foam Master. Henkel) Acrylic copolymer viscosity 3.60 controlling
emulsion (Latekol DG. BASF) Sodium dioctyl sulfosuccinate 1.0
Ammonium hydroxide (30%) 1.0 Ammonium nitrate 1.0 Dyestuff
dispersion to standard qs colour Water 47.25
[0054] The acrylic polymer binder emulsions is of a soft
crosslinking type formulated with good tensile strength and
rewetting properties for use in non-woven applications.
Example 4
Application to Fabric
[0055] In this process, bales of textile fibre are fed into a
machine for making bonded, carded or hydroentangled non-woven
fabric. These fibres can be of one type alone or of various
combinations, for example most bonded, carded non wovens used for
wipes are made from either rayon fibres or a combination of rayon
and polyester fibres.
[0056] In the bonded, carded process the fibres are tangled
together be one or more carding units in series, whereas the
entangling takes place using high pressure water jets in
hydroentangling. In both cases, at the end of the entangling stage
the material is in continuous web form and is quite damp due to
residual water which has been used in the course of each
process.
[0057] The damp continuous web is then printed using a suitable
dilution of the concentrate of example 1 or 2 and the binder of
example 3, which is applied to isolated areas of the web. The damp,
printed web passes through a heated zone to dry the printed fabric
and cross-link the polymeric binder. These heated zones are usually
either composed of steam heated drums over which the fabric passes
and dries by contact, or else infra-red lamps which heat by
radiation, or combinations of both.
[0058] This dry printed web is then rolled up for future slitting
and cutting.
Example 5
Simulated Life Cycle of Cloth
[0059] The treated fabric is put into an automatic domestic clothes
washing machine set on a warm wash (35.degree. C.). Five cycles of
washing were applied which constitutes the simulated useful life of
the fabric. At the end of five cycles of washing the fabric is put
through the following tests to validate that biocidal performance
is still effective at the end of the working life of the
fabric.
Example 6
Standard Sensory Tests
[0060] Standard sensory tests (stayfresh tests) were applied to the
cloth to examine the resistance of the cloth to malodours produced
by bacterial attack on food residues entrapped in the cloth in the
normal course of kitchen use. Biocidal cloths produced according to
the invention gave good results when subjected to the following
tests:
AS2609.1, AS2542.1.1, As2542.1.2 and AS2542.2.3
Example 7
Standard Quantitative Microbiological Test
[0061] A biocidal cloth according to the invention was subjected to
a standard quantitative test for microorganisms. "Assessment of
Antibacterial Finishes on Textile Materials": Test Method AATCC
100-1993. This test is specifically designed for the assessment of
the biocidal properties of fabric treatments. These treatments are
designed to kill microorganisms within the fabric, rather than on
surfaces which come into contact with the fabric.
Example 8
[0062] Table II shows the effect of Pseudomonas Aeruginosa of
fabric impregnated with zinc pyridinethione (0.85%), a second
fabric impregnated with dichlorophen (0.85%) and a third fabric
impregnated with a combination of dichlorophen (0.5%) and zinc
pyridinethione (0.5%). The weights are given relative to the weight
of dry fabric. A positive sign indicates an increase in the
bacterial population and a negative sign shows a decrease.
3 TABLE II BIOCIDE DAY 1 DAY 2 zinc pyridinethione +0.845 +0.35
dichlorophen +0.439 +2.12 dichlorophen/zinc pyridinethione -0.94
-0.98
[0063] While the invention has been described herein with reference
to zinc pyridinethione, those skilled in the art will appreciate
that the use of other metal pyridinethiones also form part of the
same inventive concept.
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