U.S. patent application number 17/193099 was filed with the patent office on 2022-01-27 for self-lubricating surfaces for food packaging and food processing equipment.
This patent application is currently assigned to Massachusetts Institute of Technology. The applicant listed for this patent is Massachusetts Institute of Technology. Invention is credited to Rajeev Dhiman, Christopher J. Love, Adam T. Paxson, Jonathan David Smith, Brian R. Solomon, Kripa K. Varanasi.
Application Number | 20220024682 17/193099 |
Document ID | / |
Family ID | |
Filed Date | 2022-01-27 |
United States Patent
Application |
20220024682 |
Kind Code |
A1 |
Smith; Jonathan David ; et
al. |
January 27, 2022 |
SELF-LUBRICATING SURFACES FOR FOOD PACKAGING AND FOOD PROCESSING
EQUIPMENT
Abstract
In certain embodiments, the invention relates to an article
having a liquid-impregnated surface. The surface includes a matrix
of solid features (e.g., non-toxic and/or edible features) spaced
sufficiently close to stably contain a liquid therebetween or
therewithin, wherein the liquid is non-toxic and/or edible. The
article may contain, for example, a food or other consumer product,
such as ketchup, mustard, or mayonnaise.
Inventors: |
Smith; Jonathan David;
(Arlington, MA) ; Dhiman; Rajeev; (Pleasanton,
CA) ; Paxson; Adam T.; (Cambridge, MA) ; Love;
Christopher J.; (Atlantis, FL) ; Solomon; Brian
R.; (Rockville, MA) ; Varanasi; Kripa K.;
(Lexington, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Massachusetts Institute of Technology |
Cambridge |
MA |
US |
|
|
Assignee: |
Massachusetts Institute of
Technology
Cambridge
MA
|
Appl. No.: |
17/193099 |
Filed: |
March 5, 2021 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
15187410 |
Jun 20, 2016 |
10968035 |
|
|
17193099 |
|
|
|
|
14581068 |
Dec 23, 2014 |
9371173 |
|
|
15187410 |
|
|
|
|
13517552 |
Jun 13, 2012 |
8940361 |
|
|
14581068 |
|
|
|
|
61651545 |
May 24, 2012 |
|
|
|
61614941 |
Mar 23, 2012 |
|
|
|
International
Class: |
B65D 85/72 20060101
B65D085/72; B65D 23/02 20060101 B65D023/02; B65D 25/14 20060101
B65D025/14 |
Claims
1. An article comprising a liquid-impregnated surface, said surface
comprising a matrix of solid features spaced sufficiently close to
stably contain a liquid therebetween and/or therewithin, wherein
the features and liquid are non-toxic and/or edible.
2. The article of claim 1, and wherein the article is a container
of a consumer product.
3. The article of claim 1, wherein the solid features comprise
particles.
4. The article of claim 3, wherein the particles have an average
dimension in a range of 5 microns to 50 microns.
5. The article of claim 3, wherein the particles comprise one or
more members selected from the group consisting of insoluble
fibers, purified wood cellulose, micro-crystalline cellulose, oat
bran fiber, kaolinite (clay mineral), Japan wax (obtained from
berries), pulp (spongy part of plant stems), ferric oxide, iron
oxide, sodium formate, sodium oleate, sodium palmitate, sodium
sulfate, wax, carnauba wax, beeswax, candelilla wax, zein (from
corn), dextrin, cellulose ether, Hydroxyethyl cellulose,
Hydroxypropyl cellulose (HPC), Hydroxyethyl methyl cellulose,
Hydroxypropyl methyl cellulose (HPMC), and Ethyl hydroxyethyl
cellulose.
6. The article of claim 5, wherein the particles comprise a
wax.
7. The article of claim 3, wherein the particles are randomly
spaced.
8. The article of claim 7, wherein the particles are arranged with
average spacing of about 10 microns to about 30 microns between
adjacent particles or clusters of particles.
9. The article of claim 3, wherein the particles are
spray-deposited.
10. The article of claim 2, wherein the consumer product comprises
at least one member selected from the group consisting of ketchup,
catsup, mustard, mayonnaise, syrup, honey, jelly, peanut butter,
butter, chocolate syrup, shortening, butter, margarine, oleo,
grease, dip, yogurt, sour cream, cosmetics, shampoo, lotion, hair
gel, and toothpaste.
11. The article of claim 2, wherein the container of the consumer
product is shelf-stable when filled with the consumer product.
12. The article of claim 2, wherein the consumer product has a
viscosity of at least 100 cP at room temperature.
13. The article of claim 2, wherein the consumer product is a
non-Newtonian material.
14. The article of claim 1, wherein the liquid comprises at least
one member selected from the group consisting of a food additive
(e.g., ethyl oleate), fatty acids, proteins, and a vegetable oil
(e.g., olive oil, light olive oil, corn oil, soybean oil, rapeseed
oil, linseed oil, grapeseed oil, flaxseed oil, canola oil, peanut
oil, safflower oil, sunflower oil).
15. The article of claim 1, wherein the article is a component of
consumer product processing equipment.
16. The article of claim 1, wherein the article is a component of
food processing equipment that comes into contact with food.
17. The article of claim 1, wherein the liquid-impregnated surface
has solid-to-liquid ratio less than about 50 percent.
18. A method of manufacturing a container of a consumer product,
the method comprising: providing a substrate; applying a texture to
the substrate, the texture comprising a matrix of solid features
spaced sufficiently close to stably contain a liquid therebetween
and/or therewithin; and impregnating the matrix of solid features
with the liquid, wherein the solid features and the liquid are
non-toxic and/or edible.
19. The method of claim 18, wherein the solid features are
particles.
20. The method of claim 19, wherein the applying step comprises
spraying a mixture of a solid and a solvent onto the textured
substrate.
21-30. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to and the benefit of, and
incorporates herein by reference in its entirety, U.S. Provisional
Patent Application No. 61/614,941, filed Mar. 23, 2012, U.S.
Provisional Patent Application No. 61/651,545.
TECHNICAL FIELD
[0002] This invention relates generally to non-wetting and
self-lubricating surfaces for food and other consumer product
packaging and processing equipment.
BACKGROUND
[0003] The advent of micro/nano-engineered surfaces in the last
decade has opened up new techniques for enhancing a wide variety of
physical phenomena in thermofluids sciences. For example, the use
of micro/nano surface textures has provided nonwetting surfaces
capable of achieving less viscous drag, reduced adhesion to ice and
other materials, self-cleaning, and water repellency. These
improvements result generally from diminished contact (i.e., less
wetting) between the solid surfaces and adjacent liquids.
[0004] There is a need for improved non-wetting and
self-lubricating surfaces. A particular need exists for improved
non-wetting and self-lubricating surfaces for food packaging and
food processing equipment.
SUMMARY OF THE INVENTION
[0005] In general, the invention relates to liquid-impregnated
surfaces for use in food packaging and food processing equipment.
In some embodiments, the surfaces are used in containers or bottles
for food products, such as ketchup, mustard, mayonnaise, and other
products that are poured, squeezed, or otherwise extracted from the
containers or bottles. The surfaces allow the food products to flow
easily out of the containers or bottles. The surfaces described
herein may also prevent leaching of chemicals from the walls of a
food container or food processing equipment into the food, thereby
enhancing the health and safety of consumers. In one embodiment,
the surfaces provide barriers to diffusion of water or oxygen,
and/or protect the contained material (e.g., a food product) from
ultraviolet radiation. Cost-efficient methods for fabricating these
surfaces are described herein.
[0006] Containers having liquid encapsulated coatings described
herein demonstrate surprisingly effective food-emptying properties.
The embodiments described herein are particularly useful for use
with containers or processing equipment for foods or other consumer
products that notoriously stick to the containers or processing
equipment (e.g., containers and equipment that come into contact
with such consumer products). For example, it has been found that
the embodiments described herein are useful for use with consumer
products that are non-Newtonian fluids, particularly Bingham
plastics and thixotropic fluids. Other fluids for which embodiments
described herein work well include high viscosity fluids, high zero
shear rate viscosity fluids (shear-thinning fluids),
shear-thickening fluids, and fluids with high surface tension.
Here, fluid can mean a solid or liquid (a substance that
flows).
[0007] Bingham plastics (e.g., yield stress fluids) are fluids that
require a finite yield stress before beginning to flow. These are
more difficult to squeeze or pour out of a bottle or other
container. Examples of Bingham plastics include mayonnaise,
mustard, chocolate, tomato paste, and toothpaste. Typically,
Bingham plastics will not flow out of containers, even if held
upside down (e.g., toothpaste will not flow out of the tube, even
if held upside down). It has been found that embodiments described
herein work well for use with Bingham plastics.
[0008] Thixotropic fluids are fluids with viscosities that depend
on the time history of shear (and whose viscosities decrease as
shear is continually applied). In other words, thixotropic fluids
must be agitated over time to begin to thin. Ketchup is an example
of a thixotropic fluid, as is yogurt. Embodiments described herein
are found to work well with thixotropic fluids.
[0009] Embodiments described herein also work well with high
viscosity fluids (e.g., fluids with greater than 100 cP, greater
than 500 cP, greater than 1000 cP, greater than 3000 cP, or greater
than 5000 cP, for example). Embodiments also work well with high
zero shear rate viscosity materials (e.g., shear-thinning fluids)
above 100 cP. Embodiments also work well with high surface tension
substances, which are relevant where substances are contained in
very small bottles or tubes.
[0010] In one aspect, the invention is directed to an article
including a liquid-impregnated surface, said surface including a
matrix of solid features spaced sufficiently close to stably
contain a liquid therebetween and/or therewithin, wherein the
features and liquid are non-toxic and/or edible. In certain
embodiments, the liquid is stably contained within the matrix
regardless of orientation of the article and/or under normal
shipping and/or handling conditions. In certain embodiments, the
article is a container of a consumer product. In certain
embodiments, the solid features include particles. In certain
embodiments, the particles have an average characteristic dimension
in a range, for example, of about 5 microns to about 500 microns,
or about 5 microns to about 200 microns, or about 10 microns to
about 50 microns. In certain embodiments, the characteristic
dimension is a diameter (e.g., for roughly spherical particles), a
length (e.g., for roughly rod-shaped particles), a thickness, a
depth, or a height. In certain embodiments, the particles include
insoluble fibers, purified wood cellulose, micro-crystalline
cellulose, oat bran fiber, kaolinite (clay mineral), Japan wax
(obtained from berries), pulp (spongy part of plant stems), ferric
oxide, iron oxide, sodium formate, sodium oleate, sodium palmitate,
sodium sulfate, wax, carnauba wax, beeswax, candelilla wax, zein
(from corn), dextrin, cellulose ether, Hydroxyethyl cellulose,
Hydroxypropyl cellulose (HPC), Hydroxyethyl methyl cellulose,
Hydroxypropyl methyl cellulose (HPMC), and/or Ethyl hydroxyethyl
cellulose. In certain embodiments, the particles include a wax. In
certain embodiments, the particles are randomly spaced. In certain
embodiments, the particles are arranged with average spacing of
about 1 micron to about 500 microns, or from about 5 microns to
about 200 microns, or from about 10 microns to about 30 microns
between adjacent particles or clusters of particles. In certain
embodiments, the particles are spray-deposited (e.g., deposited by
aerosol or other spray mechanism). In certain embodiments, the
consumer product comprises at least one member selected from the
group consisting of ketchup, catsup, mustard, mayonnaise, syrup,
honey, jelly, peanut butter, butter, chocolate syrup, shortening,
butter, margarine, oleo, grease, dip, yogurt, sour cream,
cosmetics, shampoo, lotion, hair gel, and toothpaste. In certain
embodiments, a food product is sticky food (e.g., candy, chocolate
syrup, mash, yeast mash, beer mash, taffy), food oil, fish oil,
marshmallow, dough, batter, baked goods, chewing gum, bubble gum,
butter, cheese, cream, cream cheese, mustard, yogurt, sour cream,
curry, sauce, ajvar, currywurst sauce, salsa lizano, chutney,
pebre, fish sauce, tzatziki, sriracha sauce, vegemite, chimichurri,
HP sauce/brown sauce, harissa, kochujang, hoisan sauce, kim chi,
cholula hot sauce, tartar sauce, tahini, hummus, shichimi, ketchup,
Pasta sauce, Alfredo sauce, Spaghetti sauce, icing, dessert
toppings, or whipped cream. In certain embodiments, the container
of the consumer product is shelf-stable when filled with the
consumer product. In certain embodiments, the consumer product has
a viscosity of at least about 100 cP at room temperature. In
certain embodiments, the consumer product has a viscosity of at
least about 1000 cP at room temperature. In certain embodiments,
the consumer product is a non-Newtonian material. In certain
embodiments, the consumer product comprises a Bingham plastic, a
thixotropic fluid, and/or a shear-thickening substance. In certain
embodiments, the liquid includes a food additive (e.g., ethyl
oleate), fatty acids, proteins, and/or a vegetable oil (e.g.,olive
oil, light olive oil, corn oil, soybean oil, rapeseed oil, linseed
oil, grapeseed oil, flaxseed oil, canola oil, peanut oil, safflower
oil, sunflower oil). In certain embodiments, the article is a
component of consumer product processing equipment. In certain
embodiments, the article is a component of food processing
equipment that comes into contact with food. In certain
embodiments, the liquid-impregnated surface has solid-to-liquid
ratio less than about 50 percent, or less than about 25 percent, or
less than about 15 percent.
[0011] In another aspect, the invention is directed to a method of
manufacturing a container of a consumer product, the method
including the steps of: providing a substrate; applying a texture
to the substrate, the texture comprising a matrix of solid features
spaced sufficiently close to stably contain a liquid therebetween
and/or therewithin (e.g., for example, stably contained when the
container is in any orientation, or undergoing normal shipping
and/or handling conditions throughout the useful lifetime of the
container); and impregnating the matrix of solid features with the
liquid, wherein the solid features and the liquid are non-toxic
and/or edible. In certain embodiments, the solid features are
particles. In certain embodiments, the applying step includes
spraying a mixture of a solid and a solvent onto the textured
substrate. In certain embodiments, the solid insoluble fibers,
purified wood cellulose, micro-crystalline cellulose, oat bran
fiber, kaolinite (clay mineral), Japan wax (obtained from berries),
pulp (spongy part of plant stems), ferric oxide, iron oxide, sodium
formate, sodium oleate, sodium palmitate, sodium sulfate, wax,
carnauba wax, beeswax, candelilla wax, zein (from corn), dextrin,
cellulose ether, Hydroxyethyl cellulose, Hydroxypropyl cellulose
(HPC), Hydroxyethyl methyl cellulose, Hydroxypropyl methyl
cellulose (HPMC), and/or Ethyl hydroxyethyl cellulose. In certain
embodiments, the method includes the step of allowing the solvent
to evaporate following the spraying of the mixture onto the
textured substrate and before the impregnating step. In certain
embodiments, the method includes the step of contacting the
impregnated matrix of features with a consumer product. In certain
embodiments, the consumer product is ketchup, catsup, mustard,
mayonnaise, syrup, honey, jelly, peanut butter, butter, chocolate
syrup, shortening, butter, margarine, oleo, grease, dip, yogurt,
sour cream, cosmetics, shampoo, lotion, hair gel, or toothpaste. In
certain embodiments, In certain embodiments, the consumer product
is a sticky food (e.g., candy, chocolate syrup, mash, yeast mash,
beer mash, taffy), food oil, fish oil, marshmallow, dough, batter,
baked goods, chewing gum, bubble gum, butter, cheese, cream, cream
cheese, mustard, yogurt, sour cream, curry, sauce, ajvar,
currywurst sauce, salsa lizano, chutney, pebre, fish sauce,
tzatziki, sriracha sauce, vegemite, chimichurri, HP sauce/brown
sauce, harissa, kochujang, hoisan sauce, kim chi, cholula hot
sauce, tartar sauce, tahini, hummus, shichimi, ketchup, Pasta
sauce, Alfredo sauce, Spaghetti sauce, icing, dessert toppings, or
whipped cream. In certain embodiments, the liquid includes a food
additive (e.g.,ethyl oleate), fatty acids, proteins, and/or
vegetable oil (e.g.,olive oil, light olive oil, corn oil, soybean
oil, rapeseed oil, linseed oil, grapeseed oil, flaxseed oil, canola
oil, peanut oil, safflower oil, and/or sunflower oil). In certain
embodiments, the step of applying the texture to the substrate
includes:
[0012] exposing the substrate to a solvent (e.g., solvent-induced
crystallization), extruding or blow-molding a mixture of materials,
roughening the substrate with mechanical action (e.g., tumbling
with an abrasive), spray-coating, polymer spinning, depositing
particles from solution (e.g., layer-by-layer deposition and/or
evaporating away liquid from a liquid and particle suspension),
extruding or blow-molding a foam or foam-forming material (e.g., a
polyurethane foam), depositing a polymer from a solution, extruding
or blow-molding a material that expands upon cooling to leave a
wrinkled or textured surface, applying a layer of material onto a
surface that is under tension or compression, performing
non-solvent induced phase separation of a polymer to obtain a
porous structure, performing micro-contact printing, performing
laser rastering, performing nucleation of the solid texture out of
vapor (e.g., desublimation), performing anodization, milling,
machining, knurling, e-beam milling, performing thermal or chemical
oxidation, and/or performing chemical vapor deposition. In certain
embodiments, applying the texture to the substrate includes
spraying a mixture of edible particles onto the substrate. In
certain embodiments, impregnating the matrix of features with the
liquid includes: spraying the encapsulating liquid onto the matrix
of features, brushing the liquid onto the matrix of features,
submerging the matrix of features in the liquid, spinning the
matrix of features, condensing the liquid onto the matrix of
features, depositing a solution comprising the liquid and one or
more volatile liquids, and/or spreading the liquid over the surface
with a second immiscible liquid. In certain embodiments, the liquid
is mixed with a solvent and then sprayed, because the solvent will
reduce the liquid viscosity, allowing it to spray more easily and
more uniformly. Then, the solvent will dry out of the coating. In
certain embodiments, the method further includes chemically
modifying the substrate prior to applying the texture to the
substrate and/or chemically modifying the solid features of the
texture. For example, the method may include chemically modifying
with a material having contact angle with water of greater than 70
degrees (e.g., hydrophobic material). The modification may be
conducted, for example, after the texture is applied, or may be
applied to particles prior to their application to the substrate.
In certain embodiments, impregnating the matrix of features
includes removing excess liquid from the matrix of features. In
certain embodiments, removing the excess liquid includes: using a
second immiscible liquid to carry away the excess liquid, using
mechanical action to remove the excess liquid, absorbing the excess
liquid using a porous material, and/or draining the excess liquid
off of the matrix of features using gravity or centrifugal
forces.
[0013] Elements of embodiments described with respect to a given
aspect of the invention may be used in various embodiments of
another aspect of the invention. For example, it is contemplated
that features of dependent claims depending from one independent
claim can be used in apparatus and/or methods of any of the other
independent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The objects and features of the invention can be better
understood with reference to the drawings described below, and the
claims.
[0015] FIG. 1a is a schematic cross-sectional view of a liquid
contacting a non-wetting surface, in accordance with certain
embodiments of the invention.
[0016] FIG. 1b is a schematic cross-sectional view of a liquid that
has impaled a non-wetting surface, in accordance with certain
embodiments of the invention.
[0017] FIG. 1c is a schematic cross-sectional view of a liquid in
contact with a liquid-impregnated surface, in accordance with
certain embodiments of the invention.
[0018] FIG. 2 is an SEM (Scanning Electron Microscope) image of a
typical rough surface obtained by spraying an emulsion of ethanol
and carnauba wax onto an aluminum substrate. After drying, the
particles display characteristic sizes of 10 .mu.m-50 .mu.m and
arrange into sparse clusters with characteristic spacings of 20
.mu.m-50 .mu.m between adjacent particles. These particles
constitute the first length scale of the hierarchical texture.
[0019] FIG. 3 is an SEM (Scanning Electron Microscope) image of
exemplary detail of a particle of carnauba wax obtained from a
boiled ethanol-wax emulsion and sprayed onto an aluminum substrate.
After drying, the wax particle exhibits porous sub-micron roughness
features with characteristic pore widths of 100 nm-1 .mu.m and pore
lengths of 200 nm-2 .mu.m. These porous roughness features
constitute the second length scale of the hierarchical texture.
[0020] FIG. 4 is an SEM (Scanning Electron Microscope) image of a
typical rough surface obtained by spraying an mixture of ethanol
and carnauba wax particles onto an aluminum substrate. After
drying, the particles display characteristic sizes of 10 .mu.m-50
.mu.m and arrange into dense clusters with characteristic spacings
of 10 .mu.m-30 .mu.m between adjacent particles. These particles
constitute the first length scale of the hierarchical texture.
[0021] FIG. 5 is an SEM (Scanning Electron Microscope) image of
exemplary detail of a particle of carnauba wax obtained from a wax
particle-ethanol mixture sprayed onto an aluminum substrate. After
drying, the wax particle exhibits low aspect ratio sub-micron
roughness features with heights of 100 nm. These porous roughness
features constitute the second length scale of the hierarchical
texture.
[0022] FIG. 6 is an SEM (Scanning Electron Microscope) image of a
typical rough surface obtained by spraying an emulsion of a solvent
solution and carnauba wax onto an aluminum substrate. After drying,
the particles display characteristic sizes of 10 .mu.m-10 .mu.m
with and average characteristic size of 30 .mu.m. They are sparsely
spaces with characteristic spacings of 50 .mu.m-100 .mu.m between
adjacent particles. These particles constitute the first length
scale of the hierarchical texture.
[0023] FIG. 7 is an SEM (Scanning Electron Microscope) image of
exemplary detail of a particle of carnauba wax obtained from a
solvent-wax emulsion and sprayed onto an aluminum substrate. After
drying, the wax particle exhibits sub-micron roughness features
with characteristic widths of pore widths of 200 nm and pore
lengths of 200 nm-2.mu.m. These porous roughness features
constitute the second length scale of the hierarchical texture.
[0024] FIGS. 8 through 13 include a sequence of images of a spot of
ketchup on a liquid-impregnated surface, in accordance with an
illustrative embodiment of the invention.
[0025] FIG. 14 includes a sequence of images of ketchup flowing out
of a plastic bottle, in accordance with an illustrative embodiment
of the invention.
[0026] FIG. 15 includes a sequence of images of ketchup flowing out
of a glass bottle, in accordance with an illustrative embodiment of
the invention.
[0027] FIG. 16 includes a sequence of images of mustard flowing out
of a bottle, in accordance with an illustrative embodiment of the
invention.
[0028] FIG. 17 includes a sequence of images of mayonnaise flowing
out of a bottle, in accordance with an illustrative embodiment of
the invention.
[0029] FIG. 18 includes a sequence of images of jelly flowing out
of a bottle, in accordance with an illustrative embodiment of the
invention.
[0030] FIG. 19 includes a sequence of images of sour cream and
onion dip flowing out of a bottle, in accordance with an
illustrative embodiment of the invention.
[0031] FIG. 20 includes a sequence of images of yogurt flowing out
of a bottle, in accordance with an illustrative embodiment of the
invention.
[0032] FIG. 21 includes a sequence of images of toothpaste flowing
out of a bottle, in accordance with an illustrative embodiment of
the invention.
[0033] FIG. 22 includes a sequence of images of hair gel flowing
out of a bottle, in accordance with an illustrative embodiment of
the invention.
DESCRIPTION
[0034] It is contemplated that articles, apparatus, methods, and
processes of the claimed invention encompass variations and
adaptations developed using information from the embodiments
described herein. Adaptation and/or modification of the articles,
apparatus, methods, and processes described herein may be performed
by those of ordinary skill in the relevant art.
[0035] Throughout the description, where articles and apparatus are
described as having, including, or comprising specific components,
or where processes and methods are described as having, including,
or comprising specific steps, it is contemplated that,
additionally, there are articles and apparatus of the present
invention that consist essentially of, or consist of, the recited
components, and that there are processes and methods according to
the present invention that consist essentially of, or consist of,
the recited processing steps.
[0036] It should be understood that the order of steps or order for
performing certain actions is immaterial so long as the invention
remains operable. Moreover, two or more steps or actions may be
conducted simultaneously.
[0037] The mention herein of any publication, for example, in the
Background section, is not an admission that the publication serves
as prior art with respect to any of the claims presented herein.
The Background section is presented for purposes of clarity and is
not meant as a description of prior art with respect to any
claim.
[0038] Liquid-impregnated surfaces are described in U.S. patent
application Ser. No. 13/302,356, titled "Liquid-Impregnated
Surfaces, Methods of Making, and Devices Incorporating the Same,"
filed Nov. 22, 2011, the disclosure of which is hereby incorporated
by reference herein in its entirety.
[0039] FIG. 1a is a schematic cross-sectional view of a liquid 102
in contact with a traditional or previous non-wetting surface 104
(i.e., a gas impregnating surface), in accordance with some
embodiments of the invention. The surface 104 includes a solid 106
having a surface texture defined by features 108. In some
embodiments, a solid 106 is defined by features 108. The regions
between the features 108 are occupied by a gas 110, such as air. As
depicted, while the liquid 102 is able to contact the tops of the
features 108, a gas-liquid interface 112 prevents the liquid 102
from wetting the entire surface 104.
[0040] Referring to FIG. 1b, in certain instances, the liquid 102
may displace the impregnating gas and become impaled within the
features 108 of the solid 106. Impalement may occur, for example,
when a liquid droplet impinges the surface 104 at high velocity.
When impalement occurs, the gas occupying the regions between the
features 108 is replaced with the liquid 102, either partially or
completely, and the surface 104 may lose its nonwetting
capabilities.
[0041] Referring to FIG. 1c, in certain embodiments, a non-wetting,
liquid-impregnated surface 120 is provided that includes a solid
122 having textures (e.g., features 124) that are impregnated with
an impregnating liquid 126, rather than a gas. In various
embodiments, a coating on the surface 104 includes the solid 106
and the impregnating liquid 126.
[0042] In the depicted embodiment, a contacting liquid 128 in
contact with the surface, rests on the features 124 (or other
texture) of the surface 120. In the regions between the features
124, the contacting liquid 128 is supported by the impregnating
liquid 126. In certain embodiments, the contacting liquid 128 is
immiscible with the impregnating liquid 126. For example, the
contacting liquid 128 may be water and the impregnating liquid 126
may be oil.
[0043] In some embodiments, micro-scale features are used. In some
embodiments, a micro-scale feature is a particle. Particles can be
randomly or uniformly dispersed on a surface. Characteristic
spacing between particles can be about 200 .mu.m, about 100 .mu.m,
about 90 .mu.m, about 80 .mu.m, about 70 .mu.m, about 60 .mu.m,
about 50 .mu.m, about 40 .mu.m, about 30 .mu.m, about 20 .mu.m,
about 10 .mu.m, about 5.mu.m or 1.mu.m. In some embodiments,
characteristic spacing between particles is in a range of 100
.mu.m-1.mu.m, 50 .mu.m-20 .mu.m, or 40 .mu.m-30 .mu.m. In some
embodiments, characteristic spacing between particles is in a range
of 100 .mu.m-80 .mu.m, 80 .mu.m-50 .mu.m, 50 .mu.m-30 .mu.m or 30
.mu.m-10 .mu.m. In some embodiments, characteristic spacing between
particles is in a range of any two values above.
[0044] Particles can have an average dimension of about 200 .mu.m,
about 100 .mu.m, about 90 .mu.m, about 80, about 70 .mu.m, about 60
.mu.m, about 50 .mu.m, about 40 .mu.m, about 30 .mu.m, about 20
.mu.m, about 10 .mu.m, about 5.mu.m or 1.mu.m. In some embodiments,
an average dimension of particles is in a range of 100
.mu.m-1.mu.m, 50 .mu.m-10 .mu.m, or 30 .mu.m-20 .mu.m. In some
embodiments, an average dimension of particles is in a range of 100
.mu.m-80 .mu.m, 80 .mu.m-50 .mu.m, 50 .mu.m-30 .mu.m or 30 .mu.m-10
.mu.m. In some embodiments, an average dimension of particles is in
a range of any two values above.
[0045] In some embodiments, particles are porous. Characteristic
pore size (e.g., pore widths or lengths) of particles can be about
5000 nm, about 3000 nm, about 2000 nm, about 1000 nm, about 500 nm,
about 400 nm, about 300 nm, about 200 nm, about 100 nm, about 80
nm, about 50, about 10 nm. In some embodiments, characteristic pore
size is in a range of 200 nm-2.mu.m or 100 nm-1 .mu.m. In some
embodiments, characteristic pore size is in a range of any two
values above.
[0046] The articles and methods described herein relate to
liquid-impregnated surfaces that are particularly valuable as
interior bottle coatings, and valuable to food processing
equipment. The articles and methods have applications across a
wide-range of food packaging and process equipment. For example,
the articles may be used as bottle coatings to improve the flow of
the material out of the bottle, or flow over or through food
processing equipment. In certain embodiments, the surfaces or
coatings described herein prevent leaching of chemicals from the
walls of a bottle or food processing equipment into the food,
thereby enhancing the health and safety of consumers. These
surfaces and coatings may also provide barriers to diffusion of
water or oxygen, and/or protect the contained material (e.g., a
food product) from ultraviolet radiation. In certain embodiments,
the surfaces or coatings described herein can be used with food
bins/totes/bags and/or conduits/channels in industrial
transportation setting as well as other food processing
equipments.
[0047] In certain embodiments, the articles described here are used
to contain a consumer product. For example, handling of sticky
foods, such as chocolate syrup, in coated containers leaves
significant amount of food left stuck to container walls. Coating
container walls with liquid encapsulated texture can not only
reduce food wastage but also lead to easy handling.
[0048] In certain embodiments, the articles described here are used
to contain a food product. The food product may be, for example,
ketchup, mustard, mayonnaise, butter, peanut butter, jelly, jam,
ice cream, dough, gum, chocolate syrup, yogurt, cheese, sour cream,
sauce, icing, curry, food oil or any other food product that is
provided or stored in a container. A food product can also be dog
food or cat food. The articles may also be used to contain
household products and healthcare products, such as cosmetics,
lotion, toothpaste, shampoo, hair gel, medical fluids (e.g.,
antibacterial ointments or creams), and other related products or
chemicals.
[0049] In some embodiments, a consumer product in contact with an
article has a viscosity of at least 100 cP (e.g., at room
temperature). In some embodiments, a consumer product has a
viscosity of at least 500 cP, 1000 cP, 2000 cP, 3000 cP or 5000 cP.
In some embodiments, a consumer product has a viscosity in a range
of 100-500 cP, 500-1000 cP, or 1000-2000 cP. In some embodiments, a
consumer product has a viscosity in a range of any two values
above.
[0050] In various embodiments, a liquid-impregnated surface
includes a textured, porous, or roughened substrate that is
encapsulated or impregnated by a non-toxic and/or an edible liquid.
The edible liquid may be, for example, a food additive (e.g., ethyl
oleate), fatty acids, proteins, and/or or a vegetable oil
(e.g.,olive oil, light olive oil, corn oil, soybean oil, rapeseed
oil, linseed oil, grapeseed oil, flaxseed oil, canola oil, peanut
oil, safflower oil, sunflower oil). In one embodiment, the edible
liquid is any liquid approved for consumption by the U.S. Food and
Drug Administration (FDA). The substrate is preferably listed in
the FDA's list of approved food contact substances, available at
www.accessdata.fda.gov.
[0051] In certain embodiments, a textured material on the inside of
an article (e.g., a bottle or other food container) is integral to
the bottle itself. For example, the textures of a polycarbonate
bottle may be made of polycarbonate.
[0052] In various embodiments, the solid 122 comprises a matrix of
solid features. The solid 122 or a matrix of solid features can
include a non-toxic and/or edible material. In some embodiments,
surfaces textures of a liquid-encapsulated include solid, edible
materials. For example, the surfaces textures may be formed from a
collection or coating of edible solid particles. Examples of solid,
non-toxic and/or edible materials include insoluble fibers (e.g.,
purified wood cellulose, micro-crystalline cellulose, and/or oat
bran fiber), wax (e.g., carnauba wax), and cellulose ethers (e.g.,
Hydroxyethyl cellulose, Hydroxypropyl cellulose (HPC), Hydroxyethyl
methyl cellulose, Hydroxypropyl methyl cellulose (HPMC), and/or
Ethyl hydroxyethyl cellulose).
[0053] In various embodiments, a method is provided for imparting a
surface texture (e.g., roughness and/or porosity) to the solid
substrate. In one embodiment, the texture is imparted by exposing
the substrate (e.g., polycarbonate) to a solvent (e.g., acetone).
For example, the solvent may impart texture by inducing
crystallization (e.g., polycarbonate may recrystallize when exposed
to acetone).
[0054] In various embodiments, the texture is imparted through
extrusion or blow-molding of a mixture of materials (e.g., a
continuous polymer blend, or mixture of a polymer and particles).
One of the materials may be subsequently dissolved, etched, melted,
or evaporated away, leaving a textured, porous, and/or rough
surface behind. In one embodiment, one of the materials is in the
form of particles that are larger than an average thickness of the
coating. Advantageously, packaging for food products (e.g., ketchup
bottles) is currently produced using extrusion or blow-molding.
Methods described herein may therefore be performed using existing
equipment, with little added expense.
[0055] In certain embodiments, the texture is imparted by
mechanical roughening (e.g.,tumbling with an abrasive),
spray-coating or polymer spinning, deposition of particles from
solution (e.g.,layer-by-layer deposition, evaporating away liquid
from a liquid+particle suspension), and/or extrusion or
blow-molding of a foam, or foam-forming material (for example a
polyurethane foam). Other possible methods for imparting the
texture include: deposition of a polymer from a solution (e.g., the
polymer forms a rough, porous, or textured surface behind);
extrusion or blow-molding of a material that expands upon cooling,
leaving a wrinkled surface; and application of a layer of a
material onto a surface that is under tension or compression, and
subsequently relaxing the tension or compression of surface
beneath, resulting in a textured surface.
[0056] In one embodiment, the texture is imparted through
non-solvent induced phase separation of a polymer, resulting in a
sponge-like porous structure. For example, a solution of
polysulfone, poly(vinylpyrrolidone), and DMAc may be cast onto a
substrate and then immersed in a bath of water. Upon immersion in
water, the solvent and non-solvent exchange and the polysulfone
precipitates and hardens.
[0057] In some embodiments, a liquid-impregnated surface includes
the impregnating liquid and portions of the solid material that
extend or poke through the impregnating liquid (e.g., to contact an
adjacent air phase). To achieve optimal non-wetting and
self-lubricating performance, it is generally desirable to minimize
the amount of solid material that extends through (i.e., is not
covered by) the impregnating liquid. For example, a ratio of the
solid material to the impregnating liquid at the surface is
preferably less than about 15 percent, or more preferably less than
about 5 percent. In some embodiments, a ratio of the solid material
to the impregnating liquid is less than 50 percent, 45 percent, 40
percent, 35 percent, 30 percent, 25 percent, 20 percent, 15
percent, 10 percent, 5 percent, or 2 percent. In some embodiments,
a ratio of the solid material to the impregnating liquid is in a
range of 50-5 percent, 30-10 percent, 20-15 percent or any two
values above. In certain embodiments, a low ratio is achieved using
surface textures that are pointy or round. By contrast, surface
textures that are flat may result in higher ratios, with too much
solid material exposed at the surface.
[0058] In various embodiments, a method is provided for
impregnating the surface texture with an impregnating liquid. For
example, the impregnating liquid may be sprayed or brushed onto the
texture (e.g., a texture on an inner surface of a bottle). In one
embodiment, the impregnating liquid is applied to the textured
surface by filling or partially filling a container that includes
the textured surface. The excess impregnating liquid is then
removed from the container. In various embodiments, the excess
impregnating liquid is removed by adding a wash liquid (e.g.,
water) to the container to collect or extract the excess liquid
from the container. Additional methods for adding the impregnating
liquid include spinning the container or surface in contact with
the liquid (e.g., a spin coating process), and condensing the
impregnating liquid onto the container or surface. In various
embodiments, the impregnating liquid is applied by depositing a
solution with the impregnating liquid and one or more volatile
liquids (e.g., via any of the previously described methods) and
evaporating away the one or more volatile liquids.
[0059] In certain embodiments, the impregnating liquid is applied
using a spreading liquid that spreads or pushes the impregnating
liquid along the surface. For example, the impregnating liquid
(e.g., ethyl oleate) and spreading liquid (e.g., water) may be
combined in a container and agitated or stirred. The fluid flow
within the container may distribute the impregnating liquid around
the container as it impregnates the surface textures.
[0060] With any of these methods, the excess impregnating liquid
may be mechanically removed (e.g., pushed off the surface with a
solid object or fluid), absorbed off of the surface using another
porous material, or removed via gravity or centrifugal forces. The
processing materials are preferably FDA approved for consumption in
small quantities.
EXPERIMENTAL EXAMPLES
Creating Matrix of Solid Features on Interior Bottle Surfaces:
[0061] In these experiments, 200-proof pure ethanol (KOPTEC),
powdered carnauba wax (McMaster-Carr) and aerosol carnauba wax
spray (PPE, #CW-165), which contains trichloroethylene, propane and
carnauba wax, were used. The sonicator was from Branson, Model
2510. The advanced hot plate stirrer was from VWR, Model 97042-642.
The airbrush was from Badger Air-Brush Co., Model Badger 150.
[0062] A first surface with a matrix of solid features was prepared
by procedure 1 described here. A mixture was made by heating 40 ml
ethanol to 85.degree. C., slowly adding 0.4 g carnauba wax powder,
boiling the mixture of ethanol and was for 5 min, followed by
allowing the mixture to cool while being sonicated from 5 min. The
resulting mixture was sprayed onto a substrate with an airbrush at
50 psi, and then allowing the substrate to dry at ambient
temperature and humidity for 1 min. SEM images are shown in FIGS. 2
and 3.
[0063] A second surface was prepared by procedure 2 described here.
A mixture was made by adding 4 g powdered carnauba wax to 40 ml
ethanol and vigorously stirring. The resulting mixture was sprayed
onto a substrate with an airbrush at 50 psi for 2 sec at a distance
of 4 inches from the surface, and then allowing the substrate to
dry at ambient temperature and humidity for 1 min. SEM images are
shown in FIGS. 4 and 5.
[0064] A third surface was prepared by procedure 3 described here.
An aerosol wax was sprayed onto a substrate at a distance of 10
inches for 3 sec. We moved the spray nozzle such that spray
residence time was no longer than 0.5 sec/unit area, and then
allowed the substrate to dry at ambient temperature and humidity
for 1 min. SEM images are shown in FIGS. 6 and 7.
Impregnating a Wax Coating: p A quantity of 5 to 10 mL of ethyl
oleate (sigma Aldrich) or vegetable oil was swirled around in the
bottles until the entire wax-covered surface prepared by procedure
3 described above became transparent. Such a coating time is chosen
so that cloudy (not patchy) coating forms over the whole surface.
In some embodiments, a formed coating has a thickness in a range of
10-50 microns.
[0065] The excess oil was removed by 2 different methods in the
experiments. They were either drained by placing them upside down
for about 5 minutes, or drained by adding about 50 mL of water to
the bottle and shaking it for 5-10 seconds to entrain most of the
excess oil into the water. The water/oil emulsion was then dumped
out. In general, after draining, the coating appears clear. When it
is over-drained it usually appears cloudy.
[0066] FIGS. 8 through 13 include a sequence of images of a spot of
ketchup on a liquid-impregnated surface, in accordance with an
illustrative embodiment of the invention. As depicted, the spot of
ketchup was able to slide along the liquid-impregnated surface due
to a slight tilting (e.g., 5 to 10 degrees) of the surface. The
ketchup moved along the surface as a substantially rigid body,
without leaving any ketchup residue along its path. The elapsed
time from FIG. 8 to FIG. 13 was about 1 second.
Bottle-Emptying Experiments:
[0067] Unless otherwise specified, bottle-emptying experiments were
conducted within about 30 minutes after draining excess oil. Coated
and uncoated bottles of the same type with an equal amount of the
same condiment type. They were then flipped upside down.
Plastic/glass bottles were then repeatedly squeezed/pumped until
more than 90% of the materials were removed, and then shaken until
only small drops of the material were coming out of the uncoated
bottles. The coated and uncoated bottles were then weighed, then
rinsed, then weighed again, to determine the amount of food left in
the bottles after the experiment.
Ketchup
[0068] To prepare the liquid-impregnated surface for these images
shown in FIGS. 14 and 15, an inner surface of a plastic (plastic
Heinz bottles made from polyethylene terephthalate (PETE) or glass
container was sprayed for a few seconds with a mixture containing
particles of carnauba wax and a solvent. After the solvent
evaporated, the carnauba wax that remained on the surface provided
surface texture or roughness. The surface texture was then
impregnated with ethyl oleate by applying the ethyl oleate to the
surface and removing the excess ethyl oleate.
[0069] FIGS. 14 and 15 include two sequence of images of ketchup
flowing out of a bottle, in accordance with an illustrative
embodiment of the invention. The bottle on the left in each image
is a standard ketchup bottle. The bottle on the right is a
liquid-impregnated bottle. Specifically, the inner surfaces of the
bottle on the right were liquid-impregnated prior to filling the
bottle with ketchup. Aside from the different inner surfaces, the
two bottles were identical. The sequence of images show ketchup
flowing from the two bottles due to gravity. At time equal to zero,
the initially full bottles were overturned to allow the ketchup to
pour or drip from the bottles. As depicted, the ketchup drained
considerably faster from the bottle having the liquid-impregnated
surfaces. After 200 seconds, the amount of ketchup remaining in the
standard bottle was 85.9 grams. By comparison, the amount of
ketchup remaining in the liquid-impregnated bottle at this time was
4.2 grams.
[0070] The amount of carnauba wax on the surface of the bottle was
about 9.9.times.10.sup.-5 g/cm2. The amount of ethyl oleate in the
liquid-impregnated surface was about 6.9.times.10.sup.-4 g/cm2. The
estimated coating thickness was from about 10 to about 30
micrometers.
Mustard
[0071] To prepare the liquid-impregnated surface for these images
shown in FIG. 16, an inner surface of a container was sprayed for a
few seconds with a mixture containing particles of carnauba wax and
a solvent. After the solvent evaporated, the carnauba wax that
remained on the surface provided surface texture or roughness. The
surface texture was then impregnated with ethyl oleate by applying
the ethyl oleate to the surface and removing the excess ethyl
oleate.
[0072] FIG. 16 includes a sequence of images of mustard flowing out
of a bottle, in accordance with an illustrative embodiment of the
invention. The bottle on the left in each image is a standard
mustard bottle (Grey Poupon mustard bottle). The bottle on the
right is a liquid-impregnated bottle. Specifically, the inner
surfaces of the bottle on the right were liquid-impregnated prior
to filling the bottle with mustard. Aside from the different inner
surfaces, the two bottles were identical. The sequence of images
show mustard flowing from the two bottles due to gravity. At time
equal to zero, the initially full bottles were overturned to allow
the mustard to pour or drip from the bottles. As depicted, the
mustard drained considerably faster from the bottle having the
liquid-impregnated surfaces.
Mayonnaise
[0073] To prepare the liquid-impregnated surface for these images
shown in FIG. 17, an inner surface of a container was sprayed for a
few seconds with a mixture containing particles of carnauba wax and
a solvent. After the solvent evaporated, the carnauba wax that
remained on the surface provided surface texture or roughness. The
surface texture was then impregnated with ethyl oleate by applying
the ethyl oleate to the surface and removing the excess ethyl
oleate.
[0074] FIG. 17 includes a sequence of images of mayonnaise flowing
out of a bottle, in accordance with an illustrative embodiment of
the invention. The bottle on the left in each image is a standard
mayonnaise bottle (The Hellman's Mayonnaise bottle). The bottle on
the right is a liquid-impregnated bottle. Specifically, the inner
surfaces of the bottle on the right were liquid-impregnated prior
to filling the bottle with mayonnaise. Aside from the different
inner surfaces, the two bottles were identical. The sequence of
images show mayonnaise flowing from the two bottles due to gravity.
At time equal to zero, the initially full bottles were overturned
to allow the mayonnaise to pour or drip from the bottles. As
depicted, the mayonnaise drained considerably faster from the
bottle having the liquid-impregnated surfaces.
[0075] Two days later, the experiment was repeated and the coated
bottle of mayonnaise still emptied substantially completely.
Jelly
[0076] To prepare the liquid-impregnated surface for these images
shown in FIG. 18, an inner surface of a container was sprayed for a
few seconds with a mixture containing particles of carnauba wax and
a solvent. After the solvent evaporated, the carnauba wax that
remained on the surface provided surface texture or roughness. The
surface texture was then impregnated with ethyl oleate by applying
the ethyl oleate to the surface and removing the excess ethyl
oleate.
[0077] FIG. 18 includes a sequence of images of jelly flowing out
of a bottle, in accordance with an illustrative embodiment of the
invention. The bottle on the left in each image is a standard jelly
bottle. The bottle on the right is a liquid-impregnated bottle.
Specifically, the inner surfaces of the bottle on the right were
liquid-impregnated prior to filling the bottle with jelly. Aside
from the different inner surfaces, the two bottles were identical.
The sequence of images show jelly flowing from the two bottles due
to gravity. At time equal to zero, the initially full bottles were
overturned to allow the jelly to pour or drip from the bottles. As
depicted, the jelly drained considerably faster from the bottle
having the liquid-impregnated surfaces.
[0078] In addition, experiments were tested at 55.degree. C. in a
liquid-impregnated bottle with jelly. The liquid-impregnated
surface was stable and showed similar conveying effect.
Sour Cream and Onion Dip
[0079] To prepare the liquid-impregnated surface for these images
shown in FIG. 19, an inner surface of a container was sprayed for a
few seconds with a mixture containing particles of carnauba wax and
a solvent. After the solvent evaporated, the carnauba wax that
remained on the surface provided surface texture or roughness. The
surface texture was then impregnated with canola oil by applying
the canola oil to the surface and removing the excess canola
oil.
[0080] FIG. 19 includes a sequence of images of cream flowing out
of a bottle, in accordance with an illustrative embodiment of the
invention. The bottle on the left in each image is a standard
bottle. The bottle on the right is a liquid-impregnated bottle.
Specifically, the inner surfaces of the bottle on the right were
liquid-impregnated prior to filling the bottle with cream. Aside
from the different inner surfaces, the two bottles were identical.
The sequence of images show cream flowing from the two bottles due
to gravity. At time equal to zero, the initially full bottles were
overturned to allow the cream to pour or drip from the bottles. As
depicted, the cream drained considerably faster from the bottle
having the liquid-impregnated surfaces.
Yogurt
[0081] To prepare the liquid-impregnated surface for these images
shown in FIG. 20, an inner surface of a container was sprayed for a
few seconds with a mixture containing particles of carnauba wax and
a solvent. After the solvent evaporated, the carnauba wax that
remained on the surface provided surface texture or roughness. The
surface texture was then impregnated with ethyl oleate by applying
the ethyl oleate to the surface and removing the excess ethyl
oleate.
[0082] FIG. 20 includes a sequence of images of yogurt flowing out
of a bottle, in accordance with an illustrative embodiment of the
invention. The bottle on the left in each image is a standard
bottle. The bottle on the right is a liquid-impregnated bottle.
Specifically, the inner surfaces of the bottle on the right were
liquid-impregnated prior to filling the bottle with yogurt. Aside
from the different inner surfaces, the two bottles were identical.
The sequence of images show yogurt flowing from the two bottles due
to gravity. At time equal to zero, the initially full bottles were
overturned to allow the yogurt to pour or drip from the bottles. As
depicted, the yogurt drained considerably faster from the bottle
having the liquid-impregnated surfaces.
Toothpaste
[0083] To prepare the liquid-impregnated surface for these images
shown in FIG. 21, an inner surface of a container was sprayed for a
few seconds with a mixture containing particles of carnauba wax and
a solvent. After the solvent evaporated, the carnauba wax that
remained on the surface provided surface texture or roughness. The
surface texture was then impregnated with ethyl oleate by applying
the ethyl oleate to the surface and removing the excess ethyl
oleate.
[0084] FIG. 21 includes a sequence of images of toothpaste flowing
out of a bottle, in accordance with an illustrative embodiment of
the invention. The bottle on the left in each image is a standard
bottle. The bottle on the right is a liquid-impregnated bottle.
Specifically, the inner surfaces of the bottle on the right were
liquid-impregnated prior to filling the bottle with toothpaste.
Aside from the different inner surfaces, the two bottles were
identical. The sequence of images show toothpaste flowing from the
two bottles due to gravity. At time equal to zero, the initially
full bottles were overturned to allow the toothpaste to pour or
drip from the bottles. As depicted, the toothpaste drained
considerably faster from the bottle having the liquid-impregnated
surfaces.
Hair Gel
[0085] To prepare the liquid-impregnated surface for these images
shown in FIG. 22, an inner surface of a container was sprayed for a
few seconds with a mixture containing particles of carnauba wax and
a solvent. After the solvent evaporated, the carnauba wax that
remained on the surface provided surface texture or roughness. The
surface texture was then impregnated with ethyl oleate by applying
the ethyl oleate to the surface and removing the excess ethyl
oleate.
[0086] FIG. 22 includes a sequence of images of hair gel flowing
out of a bottle, in accordance with an illustrative embodiment of
the invention. The bottle on the left in each image is a standard
bottle. The bottle on the right is a liquid-impregnated bottle.
Specifically, the inner surfaces of the bottle on the right were
liquid-impregnated prior to filling the bottle with hair gel. Aside
from the different inner surfaces, the two bottles were identical.
The sequence of images show hair gel flowing from the two bottles
due to gravity. At time equal to zero, the initially full bottles
were overturned to allow the hair gel to pour or drip from the
bottles. As depicted, the hair gel drained considerably faster from
the bottle having the liquid-impregnated surfaces.
Data from Bottle Emptying Experiments
[0087] The weight of food remaining in both the coated and uncoated
bottles used in the above-described experiments was recorded and is
presented in Table 1 below. As is clear, the weight of product
remaining in the bottles with liquid encapsulated interior surfaces
("coated bottles") after emptying is significantly less than the
weight of product remaining in the bottles without the liquid
encapsulated surfaces.
TABLE-US-00001 TABLE 1 Weight of food remaining for coated and
uncoated bottles Weight remaining Weight remaining Time of in
coated bottle in uncoated bottle shaking Heinz ketchup 4 g 86 g 200
seconds (plastic) - 36 oz Heinz ketchup 3 g 41 g 29 seconds (glass)
- 14 oz Welch's Jelly 1 g 48 g 30 seconds (plastic) - 22 oz Grey
Poupon 2 g 45 g 36 seconds Mustard (plastic) - 10 oz Honey
(plastic) 9 g 35 g 125 seconds Hellmann's 9 g 85 g 46 seconds
Mayonnaise (plastic) - 22 oz
Equivalents
[0088] While the invention has been particularly shown and
described with reference to specific preferred embodiments, it
should be understood by those skilled in the art that various
changes in form and detail may be made therein without departing
from the spirit and scope of the invention as defined by the
appended claims.
* * * * *
References