FIELD OF THE INVENTION
[0001] The present invention relates to liquid droplets comprising internal solid material
and to methods of making said liquid droplets.
BACKGROUND OF THE INVENTION
[0002] Benefit agents, such as perfumes, enzymes and the like are often delivered to a substrate
in the form of a droplet or particle. Examples of delivery agents comprising benefit
agents can be found in
US 2005/0000028 A1 and
US 8 158 571 B2. Such delivery can be achieved by using a liquid droplet which can exist within another
liquid or within the air, such as an aerosol for example. Another method is via a
loaded solid carrier material such as zeolite or starch. In this case the benefit
agent usually exists as a liquid which is applied to the carrier material and is absorbed
within the solid particle. A final approach is via core-shell particles, in which
the benefit agent is a component of a liquid core which is surrounded by a solid shell.
However, there are a number of problems encountered when using these known methods.
[0003] Loaded carrier materials suffer from two issues. The first is the ability to attach
to the substrate. Attachment often relies upon attractive forces such as charge attraction
between the solid carrier material and the substrate. If the surface has a charge
that is similar to that of the carrier material outer surface then attachment is unlikely.
Secondly, even if attachment to the substrate should be successful, movement of the
benefit agent from the carrier material to the substrate can be problematic. This
is because the solid carrier material is attached to the substrate, and so the liquid
absorbed into the carrier material may not be able to easily transfer as it is not
in direct contact with the substrate.
[0004] Liquid droplets overcome some of the disadvantages of loaded carrier materials. Firstly,
since they are liquid, they can attach to the substrate without the same requirement
as for solid particles, such as charge attraction, etc. Attachment is facilitated
by liquid-solid attachment, i.e. 'wetting'. Wetting' is essentially the extent to
which a liquid can wet a solid, and is a function of the force of adhesion between
a liquid and a solid. This type of adhesion is evident, for example, when droplets
of a liquid form on a solid surface, e.g. water droplets on glass. Furthermore, the
ability of the benefit agent to reach the substrate surface will also be improved.
This is because when the droplet adheres to the substrate, the benefit agent can easily
pass through the liquid and directly to the substrate surface. However, liquid droplets
tend to be spherical. This results in a low surface area for initial contact to the
substrate, especially if the substrate presents a low surface area to the droplet
itself, such as a natural fiber (examples being hair or cotton fiber) or a synthetic
fiber (examples being nylon or polypropylene). Hence, initial attachment tends to
be problematic.
[0005] Core-shell particles comprise a solid outer shell and a liquid inner core comprising
the benefit agent. These types of particle are often spherical, but can also be non-spherical
hence providing a higher surface area for improved initial attachment and adhesion.
However core-shell particles still suffer from the charge-based adhesion problems
and transfer of benefit agent as those of loaded carrier material particles. For either
solid particles or core-shell particles the contact area between particle and substrate
is limited because solids tend not to deform much upon contacting a substrate. This
is especially problematic when the substrate has a non-planar surface topography,
such as a curved hair or fibre.
[0006] Thus, there remains a need in the art for a benefit agent delivery particle that
at least partially overcomes the above-mentioned problems.
[0007] It has now been surprisingly found that a non-spherical liquid droplet comprising
a solid material that defines the shape of the droplet overcomes the above-mentioned
problems. The solid material allows the droplet to have a non-spherical shape, but
since the droplet is liquid over its entire surface, optimal attachment to the substrate
can be achieved due to the wetting of the substrate and spreading onto the substrate
by the liquid droplet.
SUMMARY OF THE INVENTION
[0008] The present invention is to a non-spherical liquid droplet, wherein the liquid droplet
comprises: a liquid; and an internal solid material, the internal solid material defining
the shape of the droplet; and a benefit agent; and wherein the three-phase contact
angle of the liquid on the internal solid material is less than 1°; and wherein, the
liquid droplet has a yield stress of between 100 and 1,000,000 Pascals.
[0009] The present invention is also to a composition comprising an external liquid and
the liquid droplet as described above, wherein the liquid droplet is immiscible with
the external liquid.
[0010] The present invention is also to a method of depositing a benefit agent on a substrate
comprising the steps of: (i) preparing a liquor comprising an external liquid and
a non-spherical liquid droplet, wherein the droplet comprises; (a) a liquid; and (b)
an internal solid material, the internal solid material defining the shape of the
droplet; and (c) a benefit agent; and wherein the three-phase contact angle of the
liquid on the internal solid material is less than 1°; and wherein, the liquid droplet
has a yield stress of between 100 and 1,000,000 Pascals; and wherein, the liquid droplet
is immiscible with the external liquid; and (ii) contacting the liquor with the substrate.
[0011] The present invention is also to a method for making a non-spherical droplet according
to the present invention comprising the steps of: (i) mixing a first liquid composition
comprising a molten ingredient having a yield stress of between 100 and 1,000,000
Pascals, the yield stress being measured at a temperature of 25°C and a second liquid
and a liquid benefit agent, wherein the first and second liquids and liquid benefit
agent are mixed at a temperature above 50°C to make a liquid droplet premix; (ii)
preparing a channel, wherein the channel optionally comprises a third liquid, the
third liquid being immiscible with the second liquid, and wherein the third liquid
is flowing through the channel; (iii) drawing individual droplets of the liquid droplet
premix into the channel, wherein the channel comprises a constriction to shape the
droplet; (iv) passing the premix droplets into the constriction at a temperature of
50°C or below so that the first liquid solidifies to produce liquid non-spherical
droplets; (v) depositing the non-spherical liquid droplets into a composition comprising
the third liquid, the third liquid being immiscible with the second liquid.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012]
FIG. 1 discloses examples of two-dimensional projections of three-dimensional non-spherical
liquid droplets.
FIG. 2A depicts three phase contact angle measurement.
FIG. 2B depicts three phase contact angle measurement.
FIG. 2C depicts three phase contact angle measurement.
FIG. 3 disclose non-spherical droplets according to the present invention.
FIG. 4 discloses an exemplary droplet shape making means.
DETAILED DESCRIPTION OF THE INVENTION
The non-spherical liquid droplet
[0013] The present invention is to a non-spherical liquid droplet, wherein the liquid droplet
comprises: a liquid; and an internal solid material, the internal solid material defining
the non-spherical shape of the droplet; a benefit agent; and wherein the three-phase
contact angle of the liquid on the internal solid material is less than 1°; and wherein
the liquid droplet has a yield stress ofbetween 100 Pascal and 1,000,000 Pascal, or
even between 1000 Pascal and 100,000 Pascal, or even between 5000 and 10,000 Pascal.
[0014] The yield stress of the liquid droplet is measured at a temperature of 25°C. Without
wishing to be bound by theory, the yield stress is a measure of the rheology of the
liquid droplet. The yield stress is the point at which the liquid droplet, comprising
both liquid and internal solid material, goes from being in a non-flowable state to
a flowable state. The method for determining the yield stress is described in more
detail below.
[0015] A spherical liquid droplet is a droplet in which every point on its surface is equidistant
from its centre. It should be understood that the term 'equidistant' includes a standard
degree of error of +/- 2%. A non-spherical liquid droplet is a droplet that has any
shape which is not spherical. Without wishing to be bound by theory, non-spherical
liquid droplets are advantageous because they exhibit excellent attachment to the
substrate due to the wetting effect of the liquid, but also exhibit excellent adherence
to the substrate because of the large surface area of the non-spherical droplet.
[0016] The non-spherical liquid droplet may be any non-spherical shape. A number of non-limiting
examples can be seen in FIG. 1. The diagrams in FIG. 1 represent two-dimensional projections
of three-dimensional non-spherical liquid droplets. Here the projected area is taken
to mean the area of a two-dimensional projection of a three-dimensional object onto
a flat plane such as an image provided when viewing a microscope slide where a 3D
object is placed upon the slide, or a 3D object is sandwiched between a slide and
a coverslip. The non-spherical droplet maybe rod shaped (1). Alternatively, it may
have an elongated, yet curved shape (2) or even a triangular or wedge shape (3).
[0017] A liquid droplet is understood to mean a droplet in which the entire outer surface
of the droplet is liquid (4). Even if the droplet also comprises a solid component
(5), to be a liquid droplet the solid component must be completely enclosed within
the liquid part of the droplet (4). The distance between any point on the surface
of the internal solid material (6) and the outer edge of the liquid droplet (7) may
be at least 10 nanometers, or even at least 100 nanometers, or even at least 1 micron.
[0018] The liquid can be any suitable liquid. The liquid could be an oil or an aqueous liquid.
Suitable liquids are described in more detail below. It should be noted that the materials
used in the liquid, the internal solid material and the benefit agent are all different
from one other. For example the liquid in the droplet and the benefit agent are not
the same substance. The material used for the internal solid material and droplet
liquid can be derived from the same source, for example both may be fatty alcohols,
but at room temperature the fatty alcohol in the liquid is liquid and the fatty alcohol
in the solid is solid. Hence, in this particular example, they will be different in
terms of melting point.
[0019] The internal solid material can be any suitable solid material. The internal solid
material can be porous or non-porous. Suitable internal solid materials are detailed
below. The internal solid material may comprise at least 5%, or even at least 10%,
or even at least 20%, or even at least 50% by volume of the droplet. The internal
solid material comprises at most 95% by volume of the liquid droplet. The person skilled
in the art would know how to determine the percentage using known techniques.
[0020] The internal solid material defines the shape of the liquid droplet. A liquid droplet
that does not comprise an internal solid material that defines the shape will seek
to form a sphere because of the pressure exerted by its interfacial tension, y, with
any external fluid within which it exists (as in an emulsion, for example). The pressure
exerted by the interfacial tension can be offset by an internal structure, such as
an internal solid material, within the droplet, when the yield stress of the internal
solid material matches or exceeds the pressure exerted by the interfacial tension,
allowing the droplet to stably preserve a non-spherical shape. The deformed liquid
droplet will remain stable as long as the force balance does not change. If the pressure
exerted by the interfacial tension is increased, for example by dilution of the external
liquid with a diluent, for example water, so as to exceed the yield stress of the
droplet containing the internal solid material, the droplet will transform into a
more compact shape, including a sphere or more curved form. Similarly the balance
may be shifted if the yield stress of the droplet containing internal solid material
is decreased, for example by heating to soften or melt the internal solid material
while maintaining the same/similar pressure exerted by the interfacial tension. Other
diluents can include an aqueous solution of surfactant, or an aqueous solution of
polymer, or an aqueous dispersion of colloids or mixtures thereof. Without wishing
to be bound by theory, the yield stress of the internal solid material contributes
to the overall yield stress of the liquid droplet. Hence the internal solid material
contributes to resisting deformation of the overall liquid droplet. It should be noted
that the yield stress of the internal solid material will always be greater than that
of the yield stress of the complete liquid droplet (comprising the internal solid
material). The method for determining the yield stress is described in more detail
below.
[0021] The liquid droplet comprises a benefit agent. A benefit agent is defined as a compound
or ingredient that imparts a benefit, for example cleaning, coating, substrate restoration,
colour change, reduced coefficient of friction or water repellency, sensorial, biological
agents including enzymes, probiotics, prebiotics, medicament, nutraceutical or combinations
thereof. The benefit agent is described in more detail below.
[0022] The liquid droplet has a three phase contact angle of the droplet liquid on the internal
solid material of less than 1°, a condition termed "complete wetting." 'Wettability'
is essentially the extent to which a liquid can wet a solid, and is a function of
the force of adhesion between a liquid and a solid. Wetting is a fundamental physical
property of a solid-liquid combination. In naturally non-wetting, or low wettability
situations, wetting agents such as surfactants, polymers, or colloids can be added
to modify a fluid's or solid's properties to allow wetting, between the two, that
would not occur without additives. In the context of the present invention, the surface
of the internal solid material is completely wetted by the droplet liquid. In other
words, the surface of the internal solid material is not in contact with the environment
external to the non-spherical liquid droplet. Only the outer surface of the liquid
part of the non-spherical liquid droplet is in contact with the external environment.
[0023] Without wishing to be bound by theory, the three-phase contact angle is a measure
of the capacity of the liquid to remain around the internal solid material and not
dissociate from it. In a liquid external environment if the liquid component of the
droplet does not completely wet the internal solid material, in order to achieve equilibrium,
the droplet liquid may dissociate from the solid, and independently form a liquid
droplet in the external environment. If the three-phase contact angle of the droplet
liquid component is less than 1° on the internal solid material within a volume of
external liquid material, then liquid remains around the internal solid material rather
than dissociating from it.
[0024] FIG. 2A, FIG. 2B, and FIG. 2C represent the steps in measuring the three-phase contact
angle. The three-phase contact angle is measured by placing a sample of the internal
solid material (5) into a sample of external liquid material (8). Next a droplet of
a second liquid (4) which is immiscible with the external liquid material (i.e. droplet
liquid) is placed on the solid surface (9). The contact angle (10) is then measured
as a tangent from the internal solid material surface (9) along the edge of the droplet
(11), as shown in FIG. 2A. Increasing 'wettability' of the internal solid material
by the droplet liquid material leads to a decreasing contact angle (12) (FIG. 2B)
until total wetting is seen at very low angles (13) (FIG. 2C). Increased wetting means
that the droplet liquid material preferably remains associated with the internal solid
material rather than dissociating from it. The method for determining the three-phase
contact angle is described in more detail below.
[0025] The liquid droplet may have a volume of 1 ml or less. By 'volume' we herein mean
the space occupied by the liquid droplet. The liquid droplet may have a volume of
0.8 ml or less, or even 0.6 ml or less. The liquid droplet has a volume of at least
0.5 picoliters, or even 4 picoliters, or even 35 picoliters.
[0026] The liquid droplet may have at least one orientation having a circularity of less
than 0.9, or even less than 0.8, or even less than 0.7. "Orientation" as used herein
means the two-dimensional projected area of a three-dimensional shape when viewed
from any given point. A three-dimensional shape will present different orientations
depending upon the angle or point from which it is viewed. Thus, at least one of these
orientations must have a circularity of less than 0.9. This means that from a different
orientation, or orientations, the same liquid droplet may have a circularity of greater
than 0.9. The circularity may be at least 0.1, or even 0.2, or even 0.3. Without wishing
to be bound by theory, a perfect circle has a circularity of 1.0 Circularity is a
non-unit value of the two-dimensional projected area of a particle multiplied by 4π,
and then divided by the square of the projected perimeter of the particle;

[0027] Here the projected area is taken to mean the area of a two-dimensional projection
of a three-dimensional object onto a flat plane such as an image provided when viewing
a microscope slide where a 3D object is placed upon the slide, or a 3D object is sandwiched
between a slide and a coverslip. Those skilled in the art would know how to determine
the circularity of the projection using standard equipment and techniques known in
the art. An exemplary test method is detailed below.
[0028] The liquid droplet may have at least one orientation having an aspect ratio of greater
than 1.0, or even greater than or equal to 1.5 or even greater than or equal to 2.0,
or even greater than or equal to 10 or even greater than or equal to 100. The aspect
ratio may be no greater than 200, or even no greater than 175, or even no greater
than 150. By "orientation" is meant the two-dimensional projected area of a three-dimensional
shape when viewed from any given point. A three-dimensional shape will present different
orientations depending upon the angle or point from which it is viewed. Thus, at least
one of these orientations must have an aspect ratio of at least 1.0. This means that
from a different orientation, or orientations, the same liquid droplet may have an
aspect ratio of 1 or less. The aspect ratio is determined by assigning a major and
minor axis to the projection of the liquid droplet. Here the projected area is taken
to mean the area of a two-dimensional projection of a three-dimensional object onto
a flat plane such as a microscope slide. This is achieved by fitting an artificial
bounding rectangle to the projection of the liquid droplet, where the rectangle dimensions
determine each axis value. The aspect ratio is then determined as the ratio of length
of the major to minor axis. An exemplary method of determining the aspect ratio is
described in more detail below.
Other droplets
[0029] In one embodiment, the spherical or non-spherical liquid droplet may comprise a liquid;
and an internal solid material, the internal solid material defining the shape of
the droplet; and wherein the liquid or the internal solid material, or both comprise
a benefit agent; and wherein the three-phase contact angle of the liquid on the internal
solid material is less than about 1°; and wherein, the liquid droplet has a yield
stress of between about 100 Pascal and about 100,000 Pascal, when measured at about
25°C; and wherein, the liquid and the internal solid material are chemically distinct
from one another. By "chemically distinct" is meant that the liquid and the internal
solid material have different chemistries, for example different chemical species
or compounds.
[0030] In one aspect, the non-spherical liquid droplet could be a liquid droplet comprising
a liquid; and an internal solid material, the internal solid material defining the
shape of the droplet; and wherein the three-phase contact angle of the liquid on the
internal solid material is less than about 1°; and wherein the liquid droplet has
a yield stress of between about 100 Pascal and about 1,000,000 Pascal, when measured
at about 25°C; and wherein the droplet comprises at least 10 weight percent inorganic
material; and wherein the droplet comprises at least 1 weight percent of a benefit
agent.
[0031] The droplet may comprise from 20, or even 30, or even 40, or even 50, or even 60,
or even 70, or even 80, or even 90, or even up to 100 weight percent inorganic material.
[0032] The droplet may comprise from 5, or even 10, or even 20, or even 30, or even 40,
or even 50, or even 60, or even 70, or even 80, or even 90, or even up to 100 weight
percent benefit agent.
[0033] The liquid may comprise inorganic material. Alternatively the internal solid material
may comprise inorganic material. Alternatively, both the droplet liquid and the internal
solid material may comprise inorganic material. When present in both, the weight percent
of inorganic material comprising the liquid and the solid internal material may be
the same or may differ.
[0034] The droplet may comprise various materials comprising in part or whole the droplet's
liquid and internal solid material. One or more of the materials comprising the liquid
may be comprised of one or more benefit agents comprising up to 100 weight percent
of the liquid of the droplet. One or more of the materials comprising the internal
solid may be comprised of one or more benefit agents comprising up to 100 weight percent
of the liquid of the droplet.
[0035] The inorganic material may comprise inorganic polymers.
[0036] By "inorganic materials" it is meant all substances except hydrocarbons and their
derivatives, or all substances that are not compounds of carbon, with the exception
of carbon oxides, and carbon sulfide. Suitable inorganic materials may include calcium
and zinc salts, zinc oxide, zinc pyrithione calcium-based compounds, bismuth compounds,
clays, water, or mixtures thereof. Suitable calcium-based compounds include calcium
carbonate. Suitable clays can include laponites, kaolinitie, montmorillonite, atapulgite,
illite, bentonite, halloysite and mixtures thereof. Inorganic polymers are polymers
in which the main chain contains no carbon atoms. Suitable inorganic polymers include
polysilanes, polygermanes, polystannanes, polysulfides; and heterochain polymers with
more than one type of atom in the main chain such as polyborazylenes, polysiloxanes
like polydimethylsiloxane (PDMS), polymethylhydrosiloxane (PMHS) and polydiphenylsiloxane,
polysilazanes like perhydridopolysilazane (PHPS), polyphosphazenes, polythiazyls and
mixtures thereof.
[0037] In one embodiment, the non-spherical liquid droplet may comprise a liquid; and an
internal solid material, the internal solid material defining the shape of the droplet;
and wherein the three-phase contact angle of the liquid on the internal solid material
is less than about 1°; and wherein the liquid droplet has a yield stress of between
about 100 Pascal and about 1,000,000 Pascal, when measured at about 25°C; and wherein
the droplet comprises at least 10 weight percent in total from the group of organo-compounds,
synthetic organic polymers, and semisynthetic organic polymers; and wherein the droplet
comprises at least 1 weight percent of a benefit agent.
[0038] The droplet may comprise from 20, or even 30, or even 40, or even 50, or even 60,
or even 70, or even 80, or even 90, or even up to 100 weight percent organo-compounds,
synthetic organic polymers, semisynthetic organic polymers, or mixtures thereof.
[0039] The droplet may comprise from 5, or even 10, or even 20, or even 30, or even 40,
or even 50, or even 60, or even 70, or even 80, or even 90, or even up to 100 weight
percent benefit agent.
[0040] The droplet liquid may comprise from 5, or even 10, or even 20, or even 30, or even
40, or even 50, or even 60, or even 70, or even 80, or even 90, or even up to 100
weight percent benefit agent.
[0041] The droplet liquid, the internal solid material or a combination thereof may comprise
organo-compounds, synthetic organic polymers, semisynthetic organic polymers, or a
mixture thereof.
[0042] The droplet may comprise at least 1, or even 2, or even 5, or even 10, or even 20,
or even 30, or even 40, or even 50, or even 60, or even 70, or even 80, or even 90,
or even 100 weight percent organo-compound material. The droplet may comprise at least
1, or even 2,or even 3, or even 4, or even 5, or even 10, or even 20, or even 30,
or even 40, or even 50, or even 60, or even 70, or even 80, or even 90, or even 100
weight percent of a benefit agent. Organo-compound material is an organic compound
to which one or more non-oxygen hetero-atoms replace one or more carbon atoms in a
hydrocarbon chain of an organic material and/or acts in the stead of a carbon atom
in an otherwise hydrocarbon chain of an organic material. Example organo compounds,
including polymeric forms, include: thio-compounds (also known as sulfur-containing
organo compounds such as thiols, sulfides, and disulfides); phosphorous-containing
compounds (such as phosphines and phosphoniums); nitrogen-containing compounds (such
as amines and ammonium); organosilicon compounds (such as silanes, silyl halides,
silanols, siloxanes, alkoxysilanes, silizanes, and polydimethylsiloxane); organoboron
compounds (such as boranes); organometallic compounds; organoclay (also known as organopolysilicate)
compounds such as kaolin or montmorillonite to which an organic structure has been
chemically bonded; organotin compounds; organozinc compounds; and mixtures thereof.
The organo-compound material may be comprised of one or more organo compounds.
[0043] The droplet may comprise at least 1, or even 2, or even 5, or even 10, or even 20,
or even 30, or even 40, or even 50, or even 60, or even 70, or even 80, or even 90,
or even 100 weight percent of a synthetic organic polymer or a semisynthetic organic
polymer. Semisynthetic involves additional actions beyond hydrogenating a natural
polymer to increase its degree of saturation.
[0044] Synthetic organic polymer materials include thermoplastics such as Acrylonitrile
butadiene styrene (ABS), Acrylic, Celluloid, Cellulose acetate, Ethylene-Vinyl Acetate
(EVA), Ethylene vinyl alcohol (EVAL), Fluoroplastics (PTFEs, including FEP, PFA, CTFE,
ECTFE, ETFE), Ionomers, acrylic/PVC alloy (such as Kydex, a trademarked product),
Liquid Crystal Polymer (LCP), Polyacetal (POM or Acetal), Polyacrylates (Acrylic),
Polyacrylonitrile (PAN or Acrylonitrile), Polyamide (PA or Nylon), Polyamide-imide
(PAI), Polyaryletherketone (PAEK or Ketone), Polybutadiene (PBD), Polybutylene (PB),
Polybutylene terephthalate (PBT), Polyethylene terephthalate (PET), Polycyclohexylene
dimethylene terephthalate (PCT), Polycarbonate (PC), Polyhydroxyalkanoates (PHAs),
Polyketone (PK), Polyester, Polyethylene (PE) including low density (LDPE) and high
density (HDPE) versions, Polyetheretherketone (PEEK), Polyetherimide (PEI), Polyethersulfone
(PES), Polysulfone, Polyethylenechlorinates (PEC), Polyimide (PI), Polylactic acid
(PLA), Polymethylpentene (PMP), Polyphenylene oxide (PPO), Polyphenylene sulfide (PPS),
Polyphthalamide (PPA), Polypropylene (PP), Polystyrene (PS), Polysulfone (PSU), Polyvinyl
chloride (PVC), Polyvinylidene chloride (PVDC), Fluoropolymer (e.g., Spectralon),
or mixtures thereof. Semisynthetic organic polymer materials include cross-linked
thermosets such as those involving epoxy, phenol formaldehyde, urea formaldehyde,
phenolics, alkyds, amino resins, polyesters, epoxides, silicones, proteins; other
cross-linked materials such as natural and synthetic rubbers (which may be cured,
for example, via vulcanization); and mixtures thereof. Semisynthetic organic polymer
materials include cellulosics (such as cellulose gum, cellulose triacetate, nitrocellulose,
rayon, cellophane and other modified celluloses), and modified starches (including
those that have been physically treated, enzymatically treated, or chemically treated,
such as by acetylation, chlorinations and acid hydrolysis), and mixtures thereof.
[0045] In one aspect, the non-spherical liquid droplet comprises a liquid; and an internal
solid material, the internal solid material defining the shape of the droplet; and
wherein the three-phase contact angle of the liquid on the internal solid material
is less than about 1°; and wherein the liquid droplet has a yield stress of between
about 100 Pascal and about 1,000,000 Pascal, when measured at about 25°C; and wherein
the droplet comprises less than 95 weight percent lipid material; and wherein the
droplet comprises at least 1 weight percent of a benefit agent.
[0046] The droplet may comprise less than 80, or even less than 70, or even less than 60,
or even less than 50, or even less than 40, or even less than 30 weight percent lipid
material.
[0047] The droplet may comprise from 5, or even 10, or even 20, or even 30, or even 40,
or even 50, or even 60, or even 70, or even 80, or even 90, or even up to 100 weight
percent benefit agent.
[0048] The droplet liquid may comprise from 5, or even 10, or even 20, or even 30, or even
40, or even 50, or even 60, or even 70, or even 80, or even 90, or even up to 100
weight percent benefit agent.
[0049] In one embodiment the non-spherical liquid droplet comprises a liquid; and an internal
solid material, the internal solid material defining the shape of the droplet; and
wherein the three-phase contact angle of the liquid on the internal solid material
is less than about 1°; and wherein the liquid droplet has a yield stress of between
about 100 Pascal and about 1,000,000 Pascal, when measured at about 25°C; and wherein
the droplet comprises less than 95 weight percent total hydrocarbons; and wherein
the droplet comprises at least 1 weight percent of a benefit agent.
[0050] The droplet may comprise less than 80, or even less than 70, or even less than 60,
or even less than 50, or even less than 40, or even less than 30 weight percent hydrocarbon
material.
[0051] The droplet may comprise from 5, or even 10, or even 20, or even 30, or even 40,
or even 50, or even 60, or even 70, or even 80, or even 90, or even up to 100 weight
percent benefit agent.
[0052] The droplet liquid may comprise from 5, or even 10, or even 20, or even 30, or even
40, or even 50, or even 60, or even 70, or even 80, or even 90, or even up to 100
weight percent benefit agent.
[0053] Lipids constitute a broad group of naturally occurring molecules that include fats,
waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E, and K), monoglycerides,
diglycerides, triglycerides, phospholipids, and others. Lipids may be derived from
an organism such as animal, fungus, micro-organism, or plant. The droplet may comprise
at least 1, or even 2, or even 3, or even 4, or even 5, or even 10, or even 20, or
even 30, or even 40, or even 50, or even 60, or even 70, or even 80, or even 90, or
even 100 weight percent of a benefit agent.
[0054] The droplet may comprise up to 95 weight percent lipid material. The droplet may
comprise less than 1, or even 2, or even 5, or even 10, or even 20, or even 30, or
even 40, or even 50, or even 60, or even 70, or even 80,or even 90 weight percent
lipid. The total weight of the lipid of the droplet can be wholly comprised within
the liquid or the internal solid material, or may be apportioned between the liquid
and the internal solid material in respective ratios, which add up to no greater than
100%, of: more than or equal to 10% and less than or equal to 90%, more than or equal
to 20% and less than or equal to 80%, more than or equal to 30% and less than or equal
to 70%, more than or equal to 40% and less than or equal to 60%, more than or equal
to 50% and less than or equal to 50%, more than or equal to 60% and less than or equal
to 40%, more than or equal to 70% and less than or equal to 30%, more than or equal
to 80% and less than or equal to 20%, and more than or equal to 90% and less than
or equal to 10%. In another example, the droplet may comprise a liquid that is 100%
lipid and an internal solid material that is comprised of less than 100%, less than
90%, less than 80%, less than 70%, less than 60%, less than 50%, less than 40%, less
than 30%, less than 20%, less than 10% lipid or contain no lipid. In another example,
the internal solid material may comprise a liquid that is 100% lipid and a droplet
that is comprised of less than 100%, less than 90%, less than 80%, less than 70%,
less than 60%, less than 50%, less than 40%, less than 30%, less than 20%, less than
10% lipid or contain no lipid.
[0055] The remainder of the droplet may comprise non-lipid material, such as inorganic polymers;
hydrocarbons; organo-compound materials; synthetic organic polymers; semisynthetic
organic polymers; alkyl halides; peroxides; carbohydrates including sugars, simple
starches, polysaccharides (such as starches, cellulose), pectins, gums (such as gellan
and xanthan), or mixtures thereof. The droplet may also comprise non-lipidic materials
such as aliphatic compounds (including paraffin, also known as alkane compounds),
olefinic compounds, and acetylenic compounds; cyclic compounds which include alicyclic
compounds, aromatic hydrocarbon compounds, and heterocyclic compounds including pyroles,
furans, and thiazoles; alcohols including fatty alcohols; ethers; aldehydes and ketones
or mixtures thereof.
[0056] Hydrocarbons are organic compounds consisting exclusively of the elements carbon
and hydrogen. Hydrocarbons may be derived from oil, petroleum, coal, or natural gas.
The droplet may comprise up to 95 weight percent hydrocarbon material. The droplet
may comprise at least 1, or even 2, or even 3, or even 4, or even 5, or even 10, or
even 20, or even 30, or even 40, or even 50, or even 60, or even 70, or even 80, or
even 90, or even 100 weight percent of a benefit agent. The droplet may comprise less
than 1, or even 2, or even 5, or even 10, or even 20, or even 30, or even 40, or even
50, or even 60, or even 70, or even 80,or even 90 weight percent hydrocarbon. The
total weight of the hydrocarbon of the droplet can be wholly comprised with the liquid
or the internal solid material, or maybe apportioned between the liquid and the internal
solid material in respective ratios, which add up to no greater than 100%, of: more
than or equal to 10% and less than or equal to 90%, more than or equal to 20% and
less than or equal to 80%, more than or equal to 30% and less than or equal to 70%,
more than or equal to 40% and less than or equal to 60%, more than or equal to 50%
and less than or equal to 50%, more than or equal to 60% and less than or equal to
40%, more than or equal to 70% and less than or equal to 30%, more than or equal to
80% and less than or equal to 20%, and more than or equal to 90% and less than or
equal to 10%.
[0057] The hydrocarbon may comprise aliphatic compounds such as paraffin (also known as
alkane compounds); olefinic compounds; acetylenic compounds; and alicyclic and aromatic
hydrocarbon compounds. The remainder of the droplet may comprise non-hydrocarbon material.
Said non-hydrocarbon material may comprise material including inorganic polymers;
lipids; organo-compound materials; non-hydrocarbon synthetic organic polymers; non-hydrocarbon
semisynthetic organic polymers; alkyl halides; peroxides; carbohydrates including
sugars, simple starches, polysaccharides (such as starches, cellulose); pectins; gums
(like gellan and xanthan); or mixtures thereof; heterocyclic compounds (such as pyroles,
furans, and thiazoles); alcohols (such as fatty alcohols); ethers; aldehydes; ketones;
and mixtures thereof.
[0058] It is noted that some organic compounds can be considered to fall into multiple groups
or classes (e.g. ethers and amines). Organic compounds maybe derived from living organisms
such as animal, fungus, micro-organism, or plant, or from non-renewable resources
such as oil, petroleum, coal, or natural gas. Organic compounds maybe extracted directly
from the source, possibly with purification, separation, distillation, or other process
steps. Organic compounds may be synthesized or prepared by one or more chemical steps,
such as by reaction, possibly involving multiple starting compounds. For example,
polymers are produced from monomers during a polymerization step. Synthetic polymers
may be formed by using a combination of monomers derived from renewable resources
such as recently living plant or animal sources; and, monomers derived from non-renewable
resources such as coal, petroleum, oil, and natural gas.
Liquid
[0059] The liquid droplet comprises a liquid (also referred to as the "droplet liquid").
The liquid can be any suitable liquid that exhibits a three-phase contact angle with
the internal solid material of less than 1°. The liquid maybe an aqueous liquid or
an oil or an alcohol.
[0060] The droplet liquid may be an oil, even a hydrophobic oil. The oil may have a melting
point of greater than 10° C, or even 5° C or even -20° C. The oil may have a melting
point no greater than 25° C, or even no greater than 22.5°C, or even no greater than
20°C.
[0061] The oil may be selected from alkanes, tri- and di- and monoglycerides, saturated
and unsaturated fatty acids, sterols, silicone oils, fluorinated oils, mineral oils,
and mixtures thereof. Oils maybe sourced from petroleum, vegetable, animal, fish or
plant materials. Oils can be derived from natural oil-containing materials, or can
be synthetically produced.
[0062] The droplet liquid may also be an aqueous liquid. The aqueous liquid may be an aqueous
solution of surfactant, an aqueous dispersion of colloidal particles, an aqueous solution
ofpolymer, or mixtures thereof. Suitable surfactants can include anionic, non-ionic,
cationic, zwitterionic, or a mixture thereof.
[0063] The droplet liquid may also be an alcohol. Suitable alcohols may include alcohols
such as ethanol, propanol, butanol, pentanol, hexanol, and octanol. It should be noted
that both the liquid and the internal solid material may comprise fatty alcohols.
Suitable alcohols may also include fatty alcohols. Fatty alcohols (such as stearyl
alcohol) making up the internal material may be distinguished from fatty alcohols
in the liquid by the fact that the fatty alcohol making up the internal solid material
has a melting point no lower than 40° C while the fatty alcohol present in the droplet
liquid has a melting point of greater than 10° C, or even 5° C or even -20° C, but
no greater than 25° C, or even no greater than 22.5°C, or even no greater than 20°C.
Internal solid material
[0064] The internal solid material may have a yield stress of at least 10,000 Pascals, or
even at least 12,500 Pascals, or even at least 15,000 Pascals. The internal solid
material may have a yield stress of at most 100,000,000,000 Pascals, or even 10,000,000,000
Pascals, or even 1,000,000,000 Pascals, or even 100,000,000 Pascals, or even 10,000,000
Pascals, or even 1,000,000 Pascals. The yield stress of the internal solid material
is measured at a temperature of 25°C.
[0065] The internal solid material may be porous or non-porous and may be water-soluble
or water-insoluble.
[0066] FIG .3 discloses non-limiting examples of the non-spherical droplets of the present
invention. The internal solid material maybe porous. By "porous" is meant a solid
material which comprises a void volume within the solid material. The void volume
may comprise the droplet liquid, or may be completely devoid of the droplet liquid.
The void volume may comprise the benefit agent. The droplet liquid (4) completely
surrounds the internal solid material (14) and the distance between any point on the
surface of the internal solid material (15) and the outer surface of the droplet (16)
can vary from another point on the surface of the internal solid material and the
outer surface of the droplet, i.e. the 'thickness' of the liquid part of the liquid
droplet may vary. Alternatively the internal solid material may be non-porous. The
internal solid material may be in the form of a shell (17) in which there exists a
chamber (18) within the solid material. This chamber (18) may contain another material.
The internal solid material may exist as a single structure, for example a single
solid structure (19) within the liquid droplet or may exist as more than one structure
(20). If there is more than one structure, these structures may or may not be in contact
with one another within the liquid droplet. The internal solid material could be an
assembly of discrete components. For example, this assembly could be comprised of
a series of rod shaped solid materials (21) which are in close contact but which comprise
a void volume between each other. In this instance, the internal solid material will
be porous due to the void volume existing between the rod shape solid materials. Alternatively,
the internal solid material may comprise a porous material (22), non-porous material
(23) in which there exists no void volume, shell material (17) or a combination thereof
(24).
[0067] The internal solid material may comprise an assembly of solid forms or components
which in their positioning make up the overall internal shape, whether it be for example
a rod or a ring-like overall shape. In one example, the shape of the internal solid
material may be rod shaped, or be an assembly of rods or splines or needles that give
an overall rod shape to the liquid droplet. The internal solid material in a rod shape
may be porous, non-porous, be a shell, or be a tube/pipe (i.e. hollow within and open
at both ends). An assembly of rods may comprise porous rods, non-porous rods, rod
shaped shells, tubes/pipes, or mixtures thereof. Alternatively, the internal solid
material may be comprised of spherically shaped forms or subcomponents (25), in which
case the internal solid material would need to be an assembly of spherical shapes
(26) which in their totality give the liquid droplet a non-spherical shape. Alternatively,
the internal solid material may have a substantially flat profile (27) (i.e., comprises
at least two sides that are substantially planar).
[0068] The solid material may be selected from waxes, polymeric materials, fatty materials,
inorganic materials or mixtures thereof. Waxes may be sourced from petroleum, vegetable,
animal, fish or plant materials. Waxes can be derived from natural wax-containing
materials or may be synthetically produced.
[0069] Suitable waxes can include synthetic waxes, mineral waxes, hydrocarbon waxes, plant
waxes, animal waxes, or mixtures thereof. Synthetic waxes can comprise polyethylene.
Mineral waxes can include ozokerite. Hydrocarbon waxes can comprise paraffins, microcrystalline
hydrocarbon waxes, petrolatum waxes, or mixtures thereof. Plant waxes can comprise
castor wax, carnauba wax, or mixtures thereof. Animal waxes can comprise beeswax,
spermaceti or mixtures thereof. Other suitable waxes can include those commercially
available under the trade names Castrolatum™, Super White Proto-Pet™, Thixcin-R™,
or mixtures thereof.
[0070] Suitable polymeric materials can include cellulose, polydimethylsiloxane, polymethylmethacrylate,
polyethylene oxide, biopolymers, or mixtures thereof. Suitable biopolymers can include
gums such as gellan, xanthan, and carrageenan or mixtures thereof. Other polymers
include polysiloxanes, polyamides, polyamines, polycarbonates, and polyesters.
[0071] Suitable fatty materials may comprise tri- and di- and monoglycerides, saturated
and unsaturated fatty acids, sterols, and fatty alcohols. Fatty alcohols (such as
stearyl alcohol) making up the internal material may be distinguished from fatty alcohols
in the liquid by the fact that the fatty alcohol making up the internal solid material
has a melting point no lower than 40° C. Suitable alcohols for the internal solid
include cetyl alcohol, stearyl alcohol, and behenyl alcohol.
[0072] Suitable inorganic materials may include zinc oxide, zinc pyrithione calcium-based
compounds, bismuth compounds, clays, or mixtures thereof. Suitable calcium-based compounds
include calcium carbonate. Suitable clays include laponites, kaolinitie, montmorillonite,
atapulgite, illite, bentonite, halloysite, and mixtures thereof.
Benefit agent
[0073] The liquid droplet comprises a benefit agent. The liquid droplet may comprise from
0.0001%, or even from 0.1 %, or even from 1% to 50 %, or even to 40%, or even to 30%,
or even to 20% by weight of the benefit agent.
[0074] The benefit agent may be a liquid or a solid. If the benefit agent is solid, then
it must have a three-phase contact angle of the droplet liquid on the solid benefit
agent of less than 1°. If the benefit agent is liquid, then if present in the droplet
liquid, the droplet liquid/benefit agent mixture must have a three-phase contact angle
on the internal solid material of less than 1°. If the benefit agent is liquid, then
if present in the internal solid material, there must be a three-phase contact angle
of the droplet liquid on the internal solid material/liquid benefit agent mixture
of less than 1°. The internal solid material/liquid benefit agent mixture can have
a yield stress of at least 10,000 Pascals, or even at least 12,500 Pascals, or even
at least 15,000 Pascals, and preferably a yield stress of at most 100,000,000,000
Pascals, or even 10,000,000,000 Pascals, or even 1,000,000,000 Pascals, or even 100,000,000
Pascals, or even 10,000,000 Pascals, or even 1,000,000 Pascals. The yield stress is
measured at a temperature of 25°C. Alternatively, a solid benefit agent may be dissolved
in a liquid, wherein the mixture comprising the liquid and dissolved solid benefit
agent has a three-phase contact angle with the internal solid material of less than
1°.
[0075] The benefit agent may be fully or partly enclosed within the internal solid material
or may be attached to the solid material. Alternatively, it may be present within
the droplet liquid, or it maybe present in both the liquid and the internal solid
material.
[0076] The benefit agent may be selected from compounds useful in cleaning compositions,
such as fabric or household cleaning compositions, body wash and body care compositions,
hair and beauty care compositions, health care compositions, or mixtures thereof.
[0077] The benefit agent maybe a surfactant. Suitable surfactants can be selected from anionic,
non-ionic, zwitterionic, cationic, or mixtures thereof. If the benefit agent is a
surfactant and the liquid present in the liquid droplet comprises a surfactant then
the two surfactants must be different. Suitable surfactants can include lipids of
biological origin such as fatty acids, acyl glycerols, glycerolphospholipids, phosphatidic
acid (and salts thereof), phosphatidylethanolamine, phosphatidylcholine (lecithin),
phosphatidylserine, phosphatidyllinositol, phosphatidylethanolamine, sphingolipids
(e.g., ceramides), sphingomyelin, cerebroside, glucocerebroside, ganglioside, steriods,
cholesterol esters (e.g., stearates), sugar-based surfactants, glucolipids, galactolipids,
and combinations thereof.
[0078] The benefit agent may be transition metal catalysts; imine bleach boosters; enzymes
such as amylases, carbohydrases, cellulases, laccases, lipases, bleaching enzymes
such as oxidases and peroxidases, proteases, pectate lyases and mannanases; sources
of peroxygen; bleach activators such as tetraacetyl ethylene diamine, oxybenzene sulphonate
bleach activators such as nonanoyl oxybenzene sulphonate, caprolactam bleach activators,
imide bleach activators such as N-nonanoyl-N-methyl acetamide, preformed peracids
such as N,N-pthaloylamino peroxycaproic acid, nonylamido peroxyadipic acid or dibenzoyl
peroxide; suds suppressing systems such as silicone based suds suppressors; brighteners;
hueing agents; photobleach; fabric-softening agents such as clay, silicone, and/or
quaternary ammonium compounds; flocculants such as polyethylene oxide; dye transfer
inhibitors such as polyvinylpyrrolidone, poly 4-vinylpyridine N-oxide and/or co-polymer
of vinylpyrrolidone, and vinylimidazole; fabric integrity components such as oligomers
produced by the condensation of imidazole and epichlorhydrin; soil dispersants and
soil anti-redeposition aids such as alkoxylated polyamines and ethoxylated ethyleneimine
polymers; anti-redeposition components such as polyesters and/or terephthalate polymers,
polyethylene glycols including polyethylene glycol substituted with vinyl alcohol
and/or vinyl acetate pendant groups; perfumes; cellulosic polymers such as methyl
cellulose, carboxymethyl cellulose, hydroxyethoxycellulose, or other alkyl or alkylalkoxy
cellulose, and hydrophobically modified cellulose; carboxylic acid and/or salts thereof,
including citric acid and/or sodium citrate; and any combination thereof.
[0079] A benefit agent can comprise perfumes, brighteners, insect repellants, silicones,
waxes, flavors, vitamins, fabric softening agents, and/or skin care agents. Suitable
benefit agents include silicones, enzymes, fragrances, perfumes, perfume raw materials,
fragrance raw materials, deodorants, odor counteractants, malodors, essential oils,
ethers, esters, ketones, alcohols, glycols, silicone hydrocarbons, cyclic hydrocarbons,
aldehydes, terpines, volatile insecticides, volatile insect repellants, volatile pesticides,
volatile antimicrobial agents, volatile fungicides, volatile herbicides and mixtures
thereof. Skin benefit agents suitable for use in the present invention may include
salicylic acid, Vitamin C, Vitamin E, Vitamin A, alpha hydroxy acids, glycolic acids,
N-6 furfuryladenine, ethyl resorcinol, niacinamide, zinc pyrithione, selenium sulphide,
octopirox, ketoconazole, climbazole and salicylic acid. Finasteride, protease inhibitors
connected with hair growth regulation, keratinization regulators (e.g., zinc pyrithione
(ZPT), tar based compositions, steroids (e.g. corticosteroids), selenium sulfide,
imidazole, ketoconazole, hydroxypyridones, and naturopathic agents); octopirox, climbazole,
trichogen; climbazole and zinc gluconate.
[0080] Oftentimes, benefit agents are expensive, therefore improved delivery, such as by
the droplet of this invention, can help make effective use of such components.
Composition comprising the liquid droplet
[0081] One aspect of the present invention is a composition comprising an external liquid
and the liquid droplet according to the present invention. The liquid droplet and
the external liquid are immiscible with one other. The composition can be, for example,
a fully formulated consumer goods product, for example a liquid detergent, shampoo,
or a liquid hand soap. Alternatively the composition could be a liquor prepared by
the consumer, for example a fabric or dish wash liquor. The composition can be a fabric
care, home care, health care, or beauty care product; a medicament; or a nutraceutical
composition.
[0082] The liquid droplet is within the external liquid. The liquid droplet is immiscible
with the external liquid. The external liquid can be a hydrophilic liquid such as
an aqueous liquid, or an oleophilic liquid such as an oil. If the external liquid
is an aqueous liquid, then the droplet liquid is an oil. Alternatively, if the external
liquid is an oil, then the droplet liquid is an aqueous liquid.
[0083] Suitable external liquids can include water, aqueous liquid comprising a surfactant,
an aqueous dispersion of colloidal particles, an aqueous solution of polymer, or mixtures
thereof.
[0084] The composition may also comprise adjunct materials other than the liquid droplets.
Adjunct ingredients can include those that are commonly found in fabric, home, beauty,
or health care compositions. Those skilled in the art would recognize such suitable
adjunct ingredients.
Method of depositing benefit agent on a substrate
[0085] The present invention also contemplates a method of depositing a benefit agent on
a substrate comprising the steps of;
- i) preparing a non-spherical liquid droplet, wherein the liquid droplet comprises;
- a) a liquid;
- b) an internal solid material, the internal solid material defining the shape of the
droplet; and
- c) a benefit agent;
wherein the three-phase contact angle of the liquid on the internal solid material
is less than 1°;
and wherein the droplet has a yield stress of between 100 Pascal and 1,000,000 Pascal,
or even between 1000 Pascal and 100,000 Pascal; and
- ii) contacting the liquid droplet with the substrate.
[0086] The liquid droplet may be in the form of an aerosol, i.e. a liquid dispersion in
air. Alternatively, the liquid droplet may be in an external liquid, wherein the liquid
droplet is immiscible in the external liquid.
[0087] The liquid droplet may be the liquid droplet according to the present invention.
The liquid, internal solid material, benefit agent, three-phase contact angle, yield
stress and external liquid are as described above.
Method of making a non-spherical droplet
[0088] Another aspect of the present invention is a method for making the non-spherical
liquid droplets of the present invention comprising the steps of;
- i) mixing a first liquid composition comprising a molten ingredient having a yield
stress of between 100 and 1,000,000 Pascals, the yield stress being measured at a
temperature of 25°C, and a second liquid and a benefit agent, wherein the first and
second liquids and benefit agent are mixed at a temperature above 50°C to make a liquid
droplet premix;
- ii) preparing a channel, wherein the channel optionally comprises a third liquid,
the third liquid being immiscible with the second liquid, and wherein the third liquid
flows through the channel;
- iii) drawing individual droplets of the liquid droplet premix into the channel, wherein
the channel comprises a constriction to shape the droplet;
- iv) passing the premix droplets into the constriction at a temperature of 50°C or
below so that the first liquid solidifies to produce liquid non-spherical droplets;
- v) depositing the non-spherical liquid droplets into a composition comprising the
third liquid, the third liquid being immiscible with the second liquid.
[0089] The liquid droplet premix comprises two separate fractions. The first fraction corresponds
to the internal solid material in a molten state and the second fraction corresponds
to the droplet liquid and the benefit agent. In order to shape the non-spherical liquid
droplet, these three components exist in the droplet premix as a homogenous mixture
at a temperature above 50°C. The benefit agent may be a liquid or a solid. If the
benefit agent is solid, then it must have a three-phase contact angle of the liquid
on the solid benefit agent of less than 1°. If the benefit agent is liquid, then when
dissolved in the droplet liquid, the droplet liquid/benefit agent mixture must have
a three-phase contact angle on the internal solid material of less than 1°. Alternatively,
a solid benefit agent may be dissolved in a liquid, wherein the mixture comprising
the liquid and dissolved solid benefit agent has a three-phase contact angle with
the internal solid material of less than 1°.
[0090] In step (iv) above, this homogenous premix is drawn into a constriction to shape
the droplet, while simultaneously cooling the mixture to a temperature of 50°C or
less. Suitable means of lowering the temperature could be a heat exchanger, for example
a water bath or a cooling jacket. As the temperature is decreased, the first fraction
(molten internal solid material) cools and solidifies in a non-spherical shape. Due
to the interactive forces between the shaped internal solid material and the liquid,
the droplet maintains a non-spherical shape. The interactive forces are explained
in more detail above in relation to the three-phase contact angle.
[0091] The constriction may be in the form of a capillary, or one in which the droplet premix
is extruded through a membrane system or one in which the droplet premix is passed
through a fiber-spinning apparatus or a mold, or a mixture thereof.
[0092] FIG. 4 shows an exemplary means to shape the liquid droplet. The droplet premix (28)
is injected into the channel (29) wherein the third liquid (30) is flowing through
the channel. Individual droplets of the droplet premix (29) pass into a restricted
capillary zone (32) in which the droplet premix is shaped into a non-spherical shape
(33). The capillary passes through a heat exchanger to lower the temperature to 50°C
or below (34). As the droplets of the liquid droplet premix pass through the cooling
means (34), the internal solid material solidifies (35).
EXAMPLES
Test methods
[0093] Circularity was measured by optical microscopy using a Zeiss Axiscop microscope, fitted with
a 20X objective lens, available from Carl Zeiss Microlmaging Inc. in Thornwood, N.Y.
A1 mL sample of a droplet dispersion was placed on a microscope slide and positioned
under the objective lens. The sample was viewed through the ocular lenses and the
focus and illumination adjusted until the droplets were visually clear. An image of
the individual droplet was then digitized using ImageJ image analysis program, available
from National Institutes of Health in Bethesda, Maryland. Using ImageJ software, the
digitized image was then analyzed using the area and perimeter analysis options to
measure the droplet's two-dimensional area and perimeter. The values reported on the
screen were then used to calculate the circularity using the equation given above.
[0094] Aspect ratio was measured by image analysis using a Zeiss Axiscop microscope, fitted with a 20X
objective lens, available from Carl Zeiss Microlmaging Inc. in Thornwood, N.Y. A1
mL sample of a droplet dispersion was placed on a microscope slide and positioned
under the objective lens. The sample was viewed through the ocular lenses and the
focus and illumination adjusted until droplets were visually clear. An image of an
individual droplet was then digitized using ImageJ image analysis program, available
from National Institutes of Health in Bethesda, Maryland. Using ImageJ software, the
digitized image was then analyzed using the bounding rectangle analysis option. The
dimensions of the bounding rectangle were then recorded from the output screen shown
and used to calculate the aspect ratio by taking the major axis value and dividing
it by the minor axis value.
[0095] Yield stress was measured using a TA Instruments AR2000 stress-controlled rheometer available
from TA Instruments of New Castle Delaware, fitted with a 40 mm 2 degree angle cone
and plate attachment.
[0096] A 0.5 gram sample was placed on the bottom plate and the temperature set to 25° C.
For a liquid material the sample was poured onto the plate, while a solid sample was
cut into a cylindrical shape having the diameter of the cone and a height of 1 millimeter.
[0097] The cone was lowered until the apparatus software determined the position of the
sample.
[0098] The sample was heated to 60° C and mixed for 5 minutes at a shear rate of 100 s
-1.
[0099] The sample was then cooled from 60° C to 25° C at 5° C per minute while oscillating
the sample with a strain of 0.1% at a frequency of 1 Hertz.
[0100] The apparatus measured and recorded the elastic modulus, G', every 10 seconds during
the oscillation.
[0101] Once 25° C was reached, G' measurement and recording continued and a gradual increase
in strain was conducted until reaching 100%. G' was plotted as a function of strain.
[0102] The value of G' will exhibit a constant plateau value at low strain values and the
critical strain is defined as the strain at which the G' first drops below its plateau
value by 20% or more.
[0103] The yield stress is then calculated as the product of the critical strain and the
G' plateau value.
[0104] For example, a sample that has a G' plateau value of 10,000 Pascals and a critical
strain of 0.2% has a yield stress of 20 Pa.
[0105] The three-phase contact angle was measured using a Kruss DSA100 droplet shape analyzer that is available from Kruss
Instruments of Hamburg Germany.
[0106] A flat sample of the solid to be characterized was prepared by cutting it so the
surface was flat and not contaminated with dust.
[0107] The first liquid to be characterized was then placed on the flat sample of the solid
at the bottom of a rectangular quartz cuvette, and the cuvette placed on the sample
plate. The cuvette was then filled with the first liquid.
[0108] A droplet of the second liquid was then placed on the surface of the solid sample.
[0109] The apparatus was then used to measure the contact angle using the contact angle
calculation function of the DSA1 software, available from Kruss Instruments of Hamburg
Germany, that performs a best-fit of the boundary of the droplet.
[0110] The interfacial tension between the droplet and external liquid was measured using a Kruss DSA100 droplet shape analyzer that is available from Kruss
Instruments of Hamburg Germany.
[0111] A syringe containing the droplet liquid was attached to the syringe holder of the
instrument and lowered into a rectangular quartz cuvette containing a sample of the
external liquid.
[0112] The droplet liquid was then pushed out of the syringe until a droplet formed in the
external liquid. The sample was equilibrated for five minutes and then photographed
using the interfacial tension function of the DSA1 software that performs a best-fit
of the droplet boundary and uses that to calculate the interfacial tension between
the two liquids.
Example 1
[0113] The following is an example of making a rod shaped droplet. A mixture of 70 wt% Vaseline™
brand petrolatum, 15 wt% Sigma Aldrich light mineral oil, and 15 wt% Shin Etsu silicone
oil (benefit agent) was mixed in a beaker. This was heated up while being mixed until
completely melted and homogeneous. A 10 millimolar solution of sodium dodecyl sulfate
in water was prepared by mixing 2.9 grams of sodium dodecyl sulfate into a liter of
water and mixing until a clear solution was formed.
[0114] Two Harvard Apparatus PHD 2000 syringe pumps were set to a temperature of 65°C. One
syringe pump was filled with the homogenous heated mixture and the other with the
sodium dodecyl sulfate composition. The pumps were connected to a Dolomite 3000436
microfluidic chip. IDEX FEP 150 micron ID tubing was connected to the outlet of the
chip. The outlet tubing of the chip was surrounded with a concentric copper tube heat
exchanger around the microfluidic chip's outlet tubing and its outer tube connected
to the reservoir of heat exchanger fluid. The compositions were flowed through the
apparatus and rod-shape droplets collected.
[0115] Alternatively, the Shin Etsu silicone oil was replaced with 15 wt% Arch Chemicals
zinc pyrithione.
Example 2
[0116] The following is an example of making a rod shaped droplet. A mixture of 70 wt% Vaseline™
brand petrolatum, 15 wt% Sigma Aldrich light mineral oil, and 15 wt% Shin Etsu silicone
oil (benefit agent) was mixed in a beaker. This was heated up while being mixed until
completely melted and homogeneous.
[0117] IDEX FEP 150 micron ID tubing was connected to the outlet of a New Era Pump Systems
metal syringe. The syringe was connected to a syringe pump. An Omega heating tape
was wrapped around the syringe and set to a temperature of 61°C. The homogenous mixture
was pumped through the apparatus and rod shaped droplets collected in a beaker comprising
a 10 millimolar solution of sodium dodecyl sulfate in water. Alternatively, the Shin
Etsu silicone oil was replaced with 15 wt% Arch Chemicals zinc pyrithione.
Example 3
[0118] Rod-shaped droplets were made as described in Example 1 above. An aqueous composition
comprising 1.6wt% linear alkyl benzene sulfonate, 0.4 wt% of hydrogenated castor oil
crystals, 10.07 wt% borax and 0.2 wt% NaOH. The aqueous composition had a yield stress
of IPa. To this the rod-shaped liquid droplets were added to a concentration of 1wt%
to make a liquid droplet composition. At a yield stress of IPa, the aqueous composition
was such that it prevented aggregation of the liquid droplets (which would give a
false positive), yet was not too viscous to pump.
[0119] The liquid droplet composition was divided in half and one of the two resulting samples
was heated to a temperature above 60° C for 15 minutes to melt the internal solid
material. Upon melting, the rod-shaped droplets assumed a spherical shape (since the
interfacial tension is no longer offset by an internal structure).
[0120] A volume of 1 ml of the composition being tested was then pushed through a 25 mm
Stainless Steel Filter Holder, available from EMD Millipore Corporation in Billerica,
Massachusetts, using a 1 mL Becton-Dickinson syringe available from Becton, Dickinson
and Company in Franklin Lakes, New Jersey. The average mesh pore size was ~ 550 µm.
The filter mesh was removed following each test and the entire mesh imaged under a
microscope to detect the amount of droplet material that was deposited.
[0121] The amount of droplet deposition was measured by optical microscopy using a Zeiss
Axioscop microscope, fitted with a 4X objective lens, available from Carl Zeiss Microlmaging
Inc. in Thornwood, N.Y. The entire filter mesh was placed on a microscope slide and
positioned under the objective lens. The sample was viewed through the ocular lenses
and the focus and illumination adjusted until the mesh was visually clear. An image
of the mesh was then digitized using the ImageJ image analysis program, available
from National Institutes of Health in Bethesda, Maryland.
[0122] Using ImageJ software, the digitized image was then analyzed to determine the area
of droplets blocking the mesh of the filter using the Measure Particle option with
the Area parameter specified as an output. Using the Summary option, the total area
of droplets in the filter mesh was determined and compared for each droplet shape.
[0123] The average area of filter blockage is reported below for each shape:
Rods: 74.60 square millimeters
Spheres: 1.55 square millimeters
[0124] As can clearly be seen from the data, a much larger area of the filter mesh was blocked
with rod-shaped liquid droplets than spherical liquid droplets. Thus, rod-shaped liquid
droplets have much better adhesion to a substrate than spherical liquid droplets.
[0125] The citation of any document is not an admission that it is prior art with respect
to any invention disclosed or claimed herein or that it alone, or in any combination
with any other reference or references, teaches, suggests or discloses any such invention.
[0126] While particular embodiments of the present invention have been illustrated and described,
it would be obvious to those skilled in the art that various other changes and modifications
can be made without departing from the scope of the invention. It is therefore intended
to cover in the appended claims all such changes and modifications that are within
the scope of this invention. using the ImageJ image analysis program, available from
National Institutes of Health in Bethesda, Maryland.
[0127] Using ImageJ software, the digitized image was then analyzed to determine the area
of droplets blocking the mesh of the filter using the Measure Particle option with
the Area parameter specified as an output. Using the Summary option, the total area
of droplets in the filter mesh was determined and compared for each droplet shape.
[0128] The average area of filter blockage is reported below for each shape:
Rods: 74.60 square millimeters
Spheres: 1.55 square millimeters
[0129] As can clearly be seen from the data, a much larger area of the filter mesh was blocked
with rod-shaped liquid droplets than spherical liquid droplets. Thus, rod-shaped liquid
droplets have much better adhesion to a substrate than spherical liquid droplets.
[0130] The dimensions and values disclosed herein are not to be understood as being strictly
limited to the exact numerical values recited. Instead, unless otherwise specified,
each such dimension is intended to mean both the recited value and a functionally
equivalent range surrounding that value. For example, a dimension disclosed as "40
mm" is intended to mean "about 40 mm."
[0131] Every document cited herein, including any cross-referenced or related patent or
application, is hereby incorporated herein by reference in its entirety unless expressly
excluded or otherwise limited. The citation of any document is not an admission that
it is prior art with respect to any invention disclosed or claimed herein or that
it alone, or in any combination with any other reference or references, teaches, suggests
or discloses any such invention. Further, to the extent that any meaning or definition
of a term in this document conflicts with any meaning or definition of the same term
in a document incorporated by reference, the meaning or definition assigned to that
term in this document shall govern.
[0132] While particular embodiments of the present invention have been illustrated and described,
it would be obvious to those skilled in the art that various other changes and modifications
can be made without departing from the spirit and scope of the invention. It is therefore
intended to cover in the appended claims all such changes and modifications that are
within the scope of this invention.