U.S. patent application number 14/519425 was filed with the patent office on 2016-04-21 for colored biocidal multi-layer structure.
The applicant listed for this patent is Ronald Steven Cok, Tomas Gerard Patrick McHugh, Alan Richard Priebe, John Joseph Scheible. Invention is credited to Ronald Steven Cok, Tomas Gerard Patrick McHugh, Alan Richard Priebe, John Joseph Scheible.
Application Number | 20160107415 14/519425 |
Document ID | / |
Family ID | 55748290 |
Filed Date | 2016-04-21 |
United States Patent
Application |
20160107415 |
Kind Code |
A1 |
Scheible; John Joseph ; et
al. |
April 21, 2016 |
COLORED BIOCIDAL MULTI-LAYER STRUCTURE
Abstract
A colored biocidal multi-layer structure includes a first layer
of a first color and a biocidal second layer on or over the first
layer. The biocidal second layer has a second color different from
the first color.
Inventors: |
Scheible; John Joseph;
(Fairport, NY) ; McHugh; Tomas Gerard Patrick;
(Webster, NY) ; Priebe; Alan Richard; (Rochester,
NY) ; Cok; Ronald Steven; (Rochester, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Scheible; John Joseph
McHugh; Tomas Gerard Patrick
Priebe; Alan Richard
Cok; Ronald Steven |
Fairport
Webster
Rochester
Rochester |
NY
NY
NY
NY |
US
US
US
US |
|
|
Family ID: |
55748290 |
Appl. No.: |
14/519425 |
Filed: |
October 21, 2014 |
Current U.S.
Class: |
428/148 ;
428/174; 428/195.1; 428/212; 428/213 |
Current CPC
Class: |
B32B 27/32 20130101;
B32B 7/02 20130101; B32B 27/30 20130101; B05D 3/108 20130101; B32B
27/16 20130101; B32B 2307/73 20130101; B32B 27/304 20130101; B32B
2255/10 20130101; B32B 2535/00 20130101; B05D 3/148 20130101; B05D
7/52 20130101; B05D 5/00 20130101; B32B 2264/104 20130101; B32B
2607/02 20130101; B32B 38/145 20130101; B32B 3/30 20130101; B32B
2264/102 20130101; B32B 2307/402 20130101; B32B 2264/10 20130101;
B32B 2307/404 20130101; B32B 2471/00 20130101; B32B 2307/412
20130101; B32B 2307/7145 20130101; B32B 2307/75 20130101; B32B
27/18 20130101; B32B 2307/70 20130101; B32B 27/08 20130101; B32B
2307/546 20130101; B32B 2439/70 20130101; B32B 2307/748 20130101;
B32B 2419/00 20130101; B32B 7/12 20130101; B05D 5/06 20130101; B32B
7/06 20130101; B32B 2307/736 20130101; B05D 3/12 20130101; B32B
2264/105 20130101; B32B 27/10 20130101; B32B 37/144 20130101 |
International
Class: |
B32B 7/02 20060101
B32B007/02; B32B 7/12 20060101 B32B007/12; B32B 7/06 20060101
B32B007/06 |
Claims
1. A colored biocidal multi-layer structure, comprising: a first
layer of a first color; and a biocidal second layer on or over the
first layer, the biocidal second layer of a second color different
from the first color.
2. The colored biocidal multi-layer structure of claim 1, wherein
at least a portion of the biocidal second layer is mechanically
separable from the first layer.
3. The colored biocidal multi-layer structure of claim 2, wherein
at least a portion of the biocidal second layer is mechanically
separable from the first layer by abrasion.
4. The colored biocidal multi-layer structure of claim 1, wherein
at least a portion of the biocidal second layer is chemically
separable from the first layer or chemically dissolvable in a
substance that does not dissolve the first layer.
5. The colored biocidal multi-layer structure of claim 1, wherein a
substance that chemically separates the biocidal second layer from
the first layer or that chemically dissolves the biocidal second
layer is a cleaning agent.
6. The colored biocidal multi-layer structure of claim 1, further
including a support, wherein the first layer has opposing first and
second sides, and the biocidal second layer is adjacent to the
first side and the support is adjacent to the second side.
7. The colored biocidal multi-layer structure of claim 6, further
including an adhesive between the first layer and the support.
8. The colored biocidal multi-layer structure of claim 1, wherein
the first color is red, is black or gray, is a dark color, or is
darker than the second color.
9. The colored biocidal multi-layer structure of claim 1, wherein
the second color is green, is blue, is white, is a light color, or
is a lighter color than the first color.
10. The colored biocidal multi-layer structure of claim 1, wherein
the biocidal second layer is thinner than the first layer.
11. The colored biocidal multi-layer structure of claim 1, wherein
the biocidal second layer includes particles.
12. The colored biocidal multi-layer structure of claim 11, wherein
the biocidal second layer includes particles that are silver,
copper, have a silver or copper component, is a salt, have a sulfur
component, is a silver sulfate salt, or includes phosphors.
13. The colored biocidal multi-layer structure of claim 11, wherein
the particles extend from the biocidal second layer surface and are
exposed.
14. The colored biocidal multi-layer structure of claim 1, wherein
the biocidal second layer has a thickness that is less than at
least one diameter of one or more of the particles, has a thickness
that is less than a mean diameter of the particles, or has a
thickness that is less than the median diameter of the
particles.
15. The colored biocidal multi-layer structure of claim 11, wherein
the particles have at least one diameter between 0.05 microns and
25 microns.
16. The colored biocidal multi-layer structure of claim 1, wherein
the biocidal second layer is greater than or equal to 0.5 micron
thick and the biocidal second layer is less than or equal to 20
microns thick.
17. The colored biocidal multi-layer structure of claim 1, wherein
the first layer includes particles.
18. The colored biocidal multi-layer structure of claim 1, wherein
the first layer and biocidal second layer both include particles,
and the particles in the first layer are the same kind of particles
as the particles in the biocidal second layer.
19. The colored biocidal multi-layer structure of claim 1, further
including a binder primer between the first layer and the biocidal
second layer.
20. The colored biocidal multi-layer structure of claim 1, wherein
the first layer is patterned or has an indicator.
21. The colored biocidal multi-layer structure of claim 20, wherein
the pattern or indicator indicates that the biocidal second layer
should be replaced.
22. The colored biocidal multi-layer structure of claim 20, wherein
the patterning is a patterning of the first color.
23. The colored biocidal multi-layer structure of claim 1, wherein
the biocidal second layer is non-planar.
24. The colored biocidal multi-layer structure of claim 1, wherein
the first layer or the biocidal second layer is hydrophobic.
25. The colored biocidal multi-layer structure of claim 1, wherein
the first layer, the biocidal second layer, or the support 30 is or
includes a heat shrink film.
26. The colored biocidal multi-layer structure of claim 1, wherein
the biocidal second layer is thicker than the first layer.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] Reference is made to commonly-assigned co-pending U.S.
patent application Ser. No. ______ (Attorney Docket No. K001887)
filed concurrently herewith, entitled Making Colored Biocidal
Multi-Layer Structure, by Scheible et al, to commonly-assigned
co-pending U.S. patent application Ser. No. ______ (Attorney Docket
No. K001888) filed concurrently herewith, entitled Using Colored
Biocidal Multi-Layer Structure, by Scheible et al, to
commonly-assigned co-pending U.S. patent application Ser. No.
13/235,789, filed Sep. 19, 2011, entitled Antibacterial and
Antifungal Protection for Toner Image, by Blanton et al, and to
commonly-assigned co-pending U.S. patent application Ser. No.
13/357,082, filed Jan. 24, 2012, entitled Ink Having Antibacterial
and Antifungal Protection, by Blanton et al, the disclosures of
which are incorporated herein.
FIELD OF THE INVENTION
[0002] The present invention relates to biocidal layers having
antimicrobial efficacy on a surface.
BACKGROUND OF THE INVENTION
[0003] Widespread attention has been focused in recent years on the
consequences of bacterial and fungal contamination contracted by
contact with common surfaces and objects. Some noteworthy examples
include the sometimes fatal outcome from food poisoning due to the
presence of particular strains of Escherichia coli in undercooked
beef; Salmonella contamination in undercooked and unwashed poultry
food products; as well as illnesses and skin irritations due to
Staphylococcus aureus and other micro-organisms. Anthrax is an
acute infectious disease caused by the spore-forming bacterium
bacillus anthracis. Allergic reactions to molds and yeasts are a
major concern to many consumers and insurance companies alike. In
addition, significant fear has arisen in regard to the development
of antibiotic-resistant strains of bacteria, such as
methicillin-resistant Staphylococcus aureus (MRSA) and
vancomycin-resistant Enterococcus (VRE). The U.S. Centers for
Disease Control and Prevention estimates that 10% of patients
contract additional diseases during their hospital stay and that
the total deaths resulting from these nosocomially-contracted
illnesses exceeds those suffered from vehicular traffic accidents
and homicides. In response to these concerns, manufacturers have
begun incorporating antimicrobial agents into materials used to
produce objects for commercial, institutional, residential, and
personal use.
[0004] Noble metal ions such as silver and gold ions are known for
their antimicrobial properties and have been used in medical care
for many years to prevent and treat infection. In recent years,
this technology has been applied to consumer products to prevent
the transmission of infectious disease and to kill harmful bacteria
such as Staphylococcus aureus and Salmonella. In common practice,
noble metals, metal ions, metal salts, or compounds containing
metal ions having antimicrobial properties can be applied to
surfaces to impart an antimicrobial property to the surface. If, or
when, the surface is inoculated with harmful microbes, the
antimicrobial metal ions or metal complexes, if present in
effective concentrations, will slow or even prevent altogether the
growth of those microbes. Recently, silver sulfate,
Ag.sub.2SO.sub.4, described in U.S. Pat. No. 7,579,396, U.S. Patent
Application Publication 2008/0242794, U.S. Patent Application
Publication 2009/0291147, U.S. Patent Application Publication
2010/0093851, and U.S. Patent Application Publication 2010/0160486
has been shown to have efficacy in providing antimicrobial
protection in polymer composites. The United States Environmental
Protection Agency (EPA) evaluated silver sulfate as a biocide and
registered its use as part of EPA Reg. No, 59441-8 EPA EST. NO.
59441-NY-001. In granting that registration, the EPA determined
that silver sulfate was safe and effective in providing
antibacterial and antifungal protection.
[0005] Antimicrobial activity is not limited to noble metals but is
also observed in other metals such as copper and organic materials
such as triclosan, and some polymeric materials.
[0006] It is important that the antimicrobial active element,
molecule, or compound be present on the surface of the article at a
concentration sufficient to inhibit microbial growth. This
concentration, for a particular antimicrobial agent and bacterium,
is often referred to as the minimum inhibitory concentration (MIC).
It is also important that the antimicrobial agent be present on the
surface of the article at a concentration significantly below that
which can be harmful to the user of the article. This prevents
harmful side effects of the article and decreases the risk to the
user, while providing the benefit of reducing microbial
contamination. There is a problem in that the rate of release of
antimicrobial ions from antimicrobial films can be too facile, such
that the antimicrobial article can quickly be depleted of
antimicrobial active materials and become inert or non-functional.
Depletion results from rapid diffusion of the active materials into
the biological environment with which they are in contact, for
example, water soluble biocides exposed to aqueous or humid
environments. It is desirable that the rate of release of the
antimicrobial ions or molecules be controlled such that the
concentration of antimicrobials remains above the MIC. The
concentration should remain there over the duration of use of the
antimicrobial article. The desired rate of exchange of the
antimicrobial can depend upon a number of factors including the
identity of the antimicrobial metal ion, the specific microbe to be
targeted, and the intended use and duration of use of the
antimicrobial article.
[0007] Antimicrobial coatings are known in the prior art, for
example as described in U.S. Patent Application Publication No.
2010/0034900. This disclosure teaches a method of coating a
substrate with biocide particles dispersed into a coating so that
the particles are in contact with the environment. Non-planar
coatings are also known to provide surface topographies for
non-toxic bio-adhesion control, for example as disclosed in U.S.
Pat. No. 7,143,709.
[0008] Fabrics or materials incorporating biocidal elements are
known in the art and commercially available. U.S. Pat. No.
5,662,991 describes a biocidal fabric with a pattern of biocidal
beads. U.S. Pat. No. 5,980,620 discloses a means of inhibiting
bacterial growth on a coated substrate comprising a substantially
dry powder coating containing a biocide. U.S. Pat. No. 6,437,021
teaches a water-insoluble polymeric support containing a biocide.
Methods for depositing thin silver-comprising films on
non-conducting substrates are taught in U.S. Patent Application
Publication No. 2014/0170298.
[0009] However, as noted above, the antimicrobial coatings and
materials lose their efficacy over time. Due to the variety of
environmental circumstances and usage patterns of such
anti-microbial coatings and materials, it is difficult to know when
they are no longer efficacious.
SUMMARY OF THE INVENTION
[0010] There is a need, therefore, for an anti-microbial article
that is readily replaced or refreshed in response to a simply
observed indication incorporated into the anti-microbial
article.
[0011] In accordance with the present invention, a colored biocidal
multi-layer structure includes:
[0012] a first layer of a first color; and
[0013] a biocidal second layer on or over the first layer, the
biocidal second layer of a second color different from the first
color.
[0014] The present invention provides a colored biocidal
multi-layer structure that provides antimicrobial properties and is
readily refreshed or replaced in response to a simply observed
indication.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The above and other features and advantages of the present
invention will become more apparent when taken in conjunction with
the following description and drawings wherein identical reference
numerals have been used to designate identical features that are
common to the figures, and wherein:
[0016] FIG. 1 is a cross section illustrating an embodiment of the
present invention;
[0017] FIG. 2 is a cross section of a multi-layer structure in
another embodiment of the present invention;
[0018] FIGS. 3 and 4 are plan views of a layer useful in
embodiments of the present invention;
[0019] FIG. 5 is a cross section of a non-planar embodiment of the
present invention; and
[0020] FIGS. 6-8 are flow diagrams illustrating methods of the
present invention.
[0021] The Figures are not drawn to scale since the variation in
size of various elements in the Figures is too great to permit
depiction to scale.
DETAILED DESCRIPTION OF THE INVENTION
[0022] The present invention provides an antimicrobial article such
as a bi-layer biocidal structure 5 shown in FIG. 1 of the present
invention that includes a simply observed indication to replace the
article. In an embodiment, the indication is related, either
directly or indirectly, to the antimicrobial efficacy of the
article or is otherwise associated with the antimicrobial efficacy
of the article. The indication is provided by apparent changes in
color of at least portions of the article. The changes are, for
example, patterns, text, or graphic elements formed in an
underlying layer that are exposed as overlying layers exposed to
the environment are degraded over time. In one method of the
present invention, the antimicrobial article is repeatedly washed
and the repeated washing removes portions of the article to expose
the indication and indicate that the article should be
replaced.
[0023] Referring to FIG. 1, in an embodiment of the present
invention, the biocidal multi-layer structure 5 includes a first
layer 10 of a first color and a biocidal second layer 20 on or over
the first layer 10. The biocidal second layer 20 has a second color
different from the first color. Any layers, for example adhesive or
environmental protection layers, located between the first layer 10
and the second layer 20 are sufficiently transparent that the color
of the first layer 10 is perceived by an observer through the
second layer 10. In an embodiment, the first or second layers 10,
20 are polymer or contain polymers, for example polymers coated as
a liquid or laminated and then cured with heat, drying, or
radiation.
[0024] In an embodiment, the first layer 10 is located on or over a
support 30, for example a substrate such as glass or plastic. In a
useful arrangement, the support 30 is adhered, for example with an
adhesive layer 50 such as a pressure-sensitive adhesive or glue
such as wall-paper glue, to a surface 8. The surface 8 is any
surface 8, planar or non-planar that is desired to resist the
growth of biologically undesirable organisms, including microbes,
bacteria, or fungi. In various applications, the surface 8 is a
surface of a structure 40, such as a wall, floor, table top, door,
handle, cover, device surface, or any surface likely to come into
contact with a human.
[0025] The support 30 is any layer that is capable of supporting
the first and second layers 10, 20 and in different embodiments is
rigid, flexible, or transparent and is made of a plastic, paper, or
vinyl or combinations of materials. The support 30 has a support
thickness 36 measured from a first support side 32 to an opposing
second support side 34 that can, for example be adhered to the
surface 8. The biocidal multi-layer structure 5 can form a wall
paper.
[0026] The first layer 10 has a first-layer thickness 16 measured
from a first-layer first side 12 to an opposing first-layer second
side 14 that is, for example, adhered to the first support side 32.
The biocidal second layer 20 has a second-layer thickness 26
measured from a second-layer first side 22 to an opposing
second-layer second side 24 that is, for example, adhered or cross
linked to the first-layer first side 12. Alternatively, an adhesion
layer such as a binder primer layer 52 (FIG. 2) is located between
the first and second layers 10, 20 to adhere the first and second
layers 10, 20 together.
[0027] The biocidal second layer 20 is a biocidal layer. By
biocidal layer is meant herein any layer that resists the growth of
undesirable biological organisms, including microbes, bacteria, or
fungi or more generally, eukaryotes, prokaryotes, or viruses. In
particular, the biocidal second layer 20 resists the growth,
reproduction, or life of infectious micro-organisms that cause
illness or death in humans and especially antibiotic-resistant
strains of bacteria. In various embodiments, the biocidal second
layer 20 is rendered biocidal by including chemicals such as drugs
in the biocidal second layer 20 or by including particles 60 such
as ionic metals or metal salts in the biocidal second layer 20. The
particles 60 reside in the biocidal second layer 20. In an
embodiment, some of the particles 60 in the biocidal second layer
20 are exposed particles 62 that extend from the second-layer first
side 22 into the environment and can interact with any
environmental contaminants or biological organisms in the
environment. Exposed particles 62 are thus more likely to be
efficacious in destroying microbes. In various embodiments, the
particles 60 are silver or copper, are a metal sulfate, have a
silver component, are a salt, have a sulfur component, have a
copper component, are a silver sulfate salt, or include phosphors.
In an embodiment, the biocidal second layer 20 is thinner than the
first layer 10 so that the second-layer thickness 26 is less than
the first-layer thickness 16, thus reducing the quantity of
particles 60 or drugs that are required in the biocidal second
layer 20. In an alternative embodiment, the second-layer thickness
26 is greater than the first-layer thickness 16.
[0028] Referring further to FIG. 2, the particles 60 of the
bi-layer biocidal structure 5 in the biocidal second layer 20 have
a variety of sizes, for example some particles are large particles
64, others are smaller particles 60, and some of either are exposed
particles 62. The particles 60 include both the large particles 64
and any exposed particles 62. In an embodiment, the biocidal second
layer 20 has a second-layer thickness 26 that is less than at least
one diameter of one or more of the particles 60, has a second-layer
thickness 26 that is less than a mean diameter of the particles 60,
or has a second-layer thickness 26 that is less than the median
diameter of the particles 60. In another embodiment, the particles
62 have at least one diameter between 0.05 and 25 microns. Suitable
particles with such a size range have been made. Alternatively, the
biocidal second layer 20 is greater than or equal to 0.5 microns
thick and the biocidal second layer 20 is less than or equal to 20
microns thick. When the second-layer thickness 26 is less than the
diameter of a substantial number of particles 60, some of the
particles 60 are not necessarily exposed particles 62.
[0029] In another embodiment and as shown in FIG. 2, the first
layer 10 includes particles 60. Alternatively, both the first layer
10 and the biocidal second layer 20 include particles 60 and the
particles 60 in the first layer 10 are the same kind of particles
60 as the particles 60 in the biocidal second layer 20.
[0030] Referring to FIGS. 3 and 4, according to embodiments of the
present invention, the first layer 10 is patterned or has an
indicator 70. The indicator 70 or pattern can be text (for example
the word "Replace"), graphic elements, pictograms, or pictures. In
an embodiment, the patterning or indicator 70 is a patterning
having the first color. Alternatively, the first layer 10 simply
has a different first color from the second color and the different
color indicates that the biocidal second layer 20 should be
replaced. Since the biocidal second layer 20 can, over time, become
ineffective and need to be replaced, the first color, the pattern
or the indicator 70 indicates that the biocidal second layer 20
should be replaced.
[0031] In various embodiments, the first color is red (a color of
alarm or emergency in many cultures), is darker than the second
color (since darker colors are associated with dirt in medical
environments), or is black or gray. Alternatively or in addition,
for similar reasons in some embodiments the second color is lighter
than the first color or is a color associated in some cultures with
cleanliness or purity, such as white, blue, or green.
[0032] Referring to FIG. 5, in an embodiment the biocidal second
layer 20 is non-planar. Such non-planar layers are made in curable
polymer layers with a stamp using imprinting methods known in the
art. As shown in FIG. 5, the first and second layers 10, 20 are
formed on the support 30. The non-planar second layer includes the
particles 60 and the exposed particles 62 and has indentations 80.
The indentations 80 form a topographical non-planar layer in the
biocidal second layer 20 that is inhospitable to the growth and
reproduction of microbes. In yet another embodiment, the first or
second layers 10, 20 have a hydrophobic surface, for example by
providing a roughened surface either by imprinting or by a
treatment such as sandblasting or exposure to energetic gases or
plasmas.
[0033] In a further embodiment of the present invention, the first
layer 10, the biocidal second layer 20, or the support 30 is or
includes a heat-shrink film, for example polyolefin,
polyvinylchloride, polyethylene, or polypropylene. Any of the first
layer 10, the biocidal second layer 20, or the support 30 can
include cross linking materials that are cross linked for example
by radiation or heat to provide strength.
[0034] FIG. 6 is a flow chart illustrating various methods of the
present invention. Referring to FIG. 6, a method of making a
colored biocidal multi-layer structure 5 includes providing the
support 30 in step 100 and forming the first layer 10 on the
support 30 in step 105. In one embodiment, the support 30 and first
layer 10 are the same structure provided as a single element. The
first layer 10 has a first color. In an optional embodiment, the
first color is patterned in the first layer 10 in step 110, for
example forming text, graphics, graphic elements, pictures, or
pictograms. In various embodiments, the support 30 is paper or
plastic and the first layer 10 is plastic, for example a polymer or
a cross linkable polymer that is curable. The first layer 10 is
patterned in any of a variety of ways known in the art, for example
by printing with ink transfer from a patterned surface or by inkjet
patterning. The first layer 10 is formed in various ways, including
extrusion or coating, for example spin coating, curtain coating, or
hopper coating, or other methods known in the art. The first layer
10 is cured, if necessary, for example by heat or radiation in step
115.
[0035] The biocidal second layer 20 is also formed in various
methods known in the art and is a biocidal layer that includes
biocidal materials such as drugs, biocides, or particles 60. The
biocidal second layer 20 has a second color different from the
first color. In an embodiment, a dispersion of particles 60 is
formed in a carrier such as a liquid in step 140 and located on the
cured first layer 10 in step 120, for example by coating, to form
the biocidal second layer 20. Making and coating liquids with
dispersed particles is known in the art. In an alternative, the
biocidal second layer 20 is made separately and laminated on or
over the first layer 10.
[0036] Optionally, the biocidal second layer 20 is imprinted in
step 125 and cured in step 130 to form the non-planar biocidal
second layer 20 including biocidal particles 60. Imprinting methods
are known in the art and employ a stamp pressed against an uncured
layer that is then cured and the stamp removed. Again optionally, a
portion of the biocidal second layer 20 is removed in step 135, for
example to expose the particles 60 to form exposed particles 62 or
increase the surface area of the exposed particles 62 that is
exposed. Removal of portions of the biocidal second layer 20 is
accomplished in step 135, for example, by exposing the biocidal
second layer 20 and particles 60 to energetic particles such as
gases or plasma, for example using processes such as etching,
plasma etching, reactive plasma etching, ion etching, or
sandblasting. Such removal methods are known in the art. In other
embodiments, the biocidal second layer 20 is formed, imprinted, and
treated before it is located on or over the first layer 10, for
example by lamination.
[0037] In step 150, a surface 8 is identified. The surface 8 is a
surface which it is desired to keep free of microbes, for example a
wall, floor, table top, door, handle, knob, cover, or device
surface, especially any surface found in a any type of medical
institution. In an embodiment, the surface 8 is planar; in another
embodiment, the surface 8 is non-planar. In step 155, an adhesive
is located, for example on the surface 8 or on the second support
side 34 of the support 30 opposite the surface 8, to form an
adhesive layer 50. The support 30 is adhered to the surface 8 in
step 160. In a further embodiment, the support 30, first layer 10,
and biocidal second layer 20 are heated to shrink the layers on the
surface 8 if the surface 8 is non-planar. In an embodiment, the
heating step (not shown separately) is also the adhesion step 160
and a separate adhesive layer 50 is not necessary or used. In an
embodiment, the biocidal second layer 20 is thinner than the first
layer 10. In another embodiment, the biocidal second layer 20 is
formed to have a thickness such that the particles 60 extend from a
surface (e.g. second-layer first side 22) of the biocidal second
layer 20 and a portion of the particle's surface area is exposed.
For example, the biocidal second layer 20 is formed with a
thickness that is less than at least one diameter of one or more of
the particles 60, has a thickness that is less than a mean diameter
of the particles 60, or has a thickness that is less than the
median diameter of the particles 60.
[0038] In a further embodiment, the first layer 10 is a biocidal
first layer 10 and includes drugs or anti-microbial particles 60.
In such an embodiment, the first layer 10 is formed as a dispersion
with particles or a liquid with multiple components that are coated
over the support 30 or formed into a layer that is laminated to the
support 30 or formed into a free-standing layer on which the
biocidal second layer 20 is located. In an alternative, the
biocidal second layer 20 includes one or more particles 60 in a
liquid and the particles 60 self-segregate in the liquid before the
liquid is cured. In an embodiment, the particles 60 self-segregate
after the liquid is coated, for example over or on first layer 10,
and before the liquid is cured to form the biocidal second layer
20. In another embodiment, the self-segregating particles aggregate
at the second-layer first side 22 of the biocidal second layer
20.
[0039] In another embodiment, the first layer 10 includes one or
more particles 60, and a method of the present invention further
includes forming the first layer 10 so that the particles 60 extend
from a portion of the surface of the first layer 10 and are exposed
and optionally further including removing a portion of the first
layer surface and increasing the exposed surface area of the
particles 60, for example by etching, plasma etching, reactive
plasma etching, ion etching, or sandblasting.
[0040] Referring to FIG. 7, in another method of the present
invention, the colored biocidal multi-layer structure 5 is used by
first locating the structure in step 200, for example on the
surface 8 on which it is desired to inhibit the presence of
microbes. The colored biocidal multi-layer structure 5 is observed
over time in step 205, especially with respect to the structure's
color or appearance and the visibility of the patterns described
above (e.g. as shown in FIGS. 3 and 4). The colored biocidal
multi-layer structure 5 and especially the biocidal second layer 20
is periodically cleaned in step 210 to remove dirt and any
microbes, alive or dead, on the surface (e.g. second-layer first
side 22) of the biocidal second layer 20. According to various
embodiments of the present invention, the cleaning process of step
210 gradually abrades or dissolves the biocidal second layer 20 so
that over time the biocidal second layer 20 is at least partially
removed and the first color or patterning of the first layer 10 is
revealed. As long as the biocidal second layer 20 remains
sufficiently in place, no color or pattern change is observed in
step 215 and the periodic cleaning continues. Eventually, the color
change is observed in step 215 and the biocidal layer 20 is
replaced in step 220.
[0041] Replacement can proceed in a variety of ways. According to
various embodiments of the present invention, the colored biocidal
multi-layer structure 5, or portions of the colored biocidal
multi-layer structure 5 are replaced when the first color of the
first layer 10 becomes apparent. In one embodiment, another colored
biocidal multi-layer structure 5 is simply located over the colored
biocidal multi-layer structure 5. Thus, the colored biocidal
multi-layer structure 5 becomes the structure 40 and another
colored biocidal multi-layer structure 5 is applied to the
structure 40, for example with an adhesive layer 50 (FIG. 1). In
another embodiment, the colored biocidal multi-layer structure 5 is
removed and another colored biocidal multi-layer structure 5 put in
its place. As shown in FIG. 1, the support 30 is adhered to the
structure 40 with an adhesive layer 50. Chemical or heat treatments
are applied to the colored biocidal multi-layer structure 5 to
loosen, dissolve, or remove the adhesive layer 50 so the colored
biocidal multi-layer structure 5 can be removed and another
adhesive layer 50 is applied to the structure 40. In an embodiment,
the colored biocidal multi-layer structure 5 is peeled from the
structure 40 and another colored biocidal multi-layer structure 5
having an adhesive layer 50 on the third-layer second support side
34 adhered to the structure 40.
[0042] Alternatively, portions of the colored biocidal multi-layer
structure 5 are removed, for example at least a portion of the
biocidal second layer 20 is mechanically separated from the first
layer 10. In an embodiment, the biocidal second layer 20 is peeled
from the first layer 10. Alternatively, the biocidal second layer
20 is abraded and removed by abrasion from the first layer 10. As
the biocidal second layer 20 is removed, the first color, pattern,
or indicator 70 of the first layer 10 becomes increasingly visible.
In another embodiment, the biocidal second layer 20 is chemically
separable from the first layer 10 or chemically dissolvable in a
substance that does not dissolve the first layer 10. In a useful
embodiment, a substance that chemically separates the biocidal
second layer 20 from the first layer 10 or that chemically
dissolves the biocidal second layer 20 is a cleaning agent. In an
embodiment, the biocidal second layer 20 is repeatedly cleaned, for
example by spraying the biocidal second layer 20 with a cleaning
agent and then rubbing or wiping the biocidal second layer 20, and
at each cleaning a portion of the biocidal second layer 20 is
removed to gradually expose the first layer 10, the first color of
the first layer 10, and the indicator 70.
[0043] Referring to FIG. 8 in another embodiment of the present
invention, fluorescent or phosphorescent materials are included in
the biocidal second layer 20 and are illuminated in step 212. The
fluorescent or phosphorescent materials respond to ultra-violet,
visible, or infrared illumination and emit light that can be seen
or detected in step 213 and compared to a threshold emission value
in step 214. Thus, the continuing presence of the biocidal second
layer 20 is observed. When light emission in response to
illumination is no longer present at a desired level, the biocidal
second layer 20 is replaced.
[0044] According to yet another embodiment of the present
invention, the cleaning step 215 refreshes the biocidal second
layer 20 so that the exposed particles 60 in the biocidal second
layer 20 are more efficacious. This can be done, for example, by
ionizing the particles 70, by removing oxidation layers on the
particles 60, or by removing extraneous materials such as dust from
the particles 70.
[0045] Useful cleaners include hydrogen peroxide, for example 2%
hydrogen peroxide, water, soap in water, or a citrus-based cleaner.
In an embodiment, the 2% hydrogen peroxide solution is reactive to
make oxygen radicals that improve the efficacy of particles 60. In
various embodiments, cleaning is accomplished by spraying the
second-layer first side 22 of the biocidal second layer 20 with a
cleaner and then wiping or rubbing the second-layer first side 22.
The cleaner can dissolve the biocidal second layer 20 material and
the wiping or rubbing can remove dissolved material or abrade the
second-layer first side 22 of the biocidal second layer 20 to
expose other particles 60 or increase the exposed surface area of
exposed particles 62.
[0046] The present invention is useful in a wide variety of
environments and on a wide variety of surfaces 8, particularly
surfaces 8 that are frequently handled by humans. The present
invention can reduce the microbial load in an environment and is
especially useful in medical facilities.
[0047] The invention has been described in detail with particular
reference to certain embodiments thereof, but it will be understood
that variations and modifications can be effected within the spirit
and scope of the invention.
PARTS LIST
[0048] 5 bi-layer biocidal structure [0049] 8 surface [0050] 10
first layer [0051] 12 first-layer first side [0052] 14 first-layer
second side [0053] 16 first-layer thickness [0054] 20 second layer
[0055] 22 second-layer first side [0056] 24 second-layer second
side [0057] 26 second-layer thickness [0058] 30 support [0059] 32
first support side [0060] 34 second support side [0061] 36 support
thickness [0062] 40 structure [0063] 50 adhesive layer [0064] 52
binder primer [0065] 60 particle [0066] 62 exposed particle [0067]
64 large particle [0068] 70 indicator [0069] 80 indentations [0070]
100 provide support step [0071] 105 provide first layer step [0072]
110 pattern first layer step [0073] 115 cure first layer step
[0074] 120 locate second layer step [0075] 125 imprint second layer
step [0076] 130 cure second layer step
PARTS LIST (CON'T)
[0076] [0077] 135 remove second layer portion step [0078] 140 form
dispersion step [0079] 150 identify surface step [0080] 155 locate
adhesive step [0081] 160 adhere support to surface step [0082] 200
locate structure step [0083] 205 observe structure step [0084] 210
clean structure step [0085] 212 illuminate structure step [0086]
213 sufficient emission comparison step [0087] 214 detect emission
step [0088] 215 observe color change step [0089] 220 replace
biocidal layer step
* * * * *