U.S. patent application number 12/815334 was filed with the patent office on 2010-12-02 for barrier compositions and articles produced with the compositions.
This patent application is currently assigned to University of Maine System Board of Trustees. Invention is credited to Michael A. Bilodeau, Anthony Jabar, JR., David J. Neivandt, Jonathan M. Spender.
Application Number | 20100301254 12/815334 |
Document ID | / |
Family ID | 43219178 |
Filed Date | 2010-12-02 |
United States Patent
Application |
20100301254 |
Kind Code |
A1 |
Jabar, JR.; Anthony ; et
al. |
December 2, 2010 |
BARRIER COMPOSITIONS AND ARTICLES PRODUCED WITH THE
COMPOSITIONS
Abstract
A stable, aqueous barrier coating composition includes: (a)
prolamine; (b) cold water insoluble polymer; (c) water; (d)
water-soluble co-solvent; and (e) stabilizer. The composition, when
applied to a substrate, produces an article having a high surface
energy and resistance to oil and grease penetration. A method of
producing the article involves applying the composition to a
substrate.
Inventors: |
Jabar, JR.; Anthony;
(Waterville, ME) ; Bilodeau; Michael A.; (Brewer,
ME) ; Neivandt; David J.; (Bangor, ME) ;
Spender; Jonathan M.; (Enfield, ME) |
Correspondence
Address: |
MACMILLAN SOBANSKI & TODD, LLC
ONE MARITIME PLAZA FIFTH FLOOR, 720 WATER STREET
TOLEDO
OH
43604-1619
US
|
Assignee: |
University of Maine System Board of
Trustees
Bangor
ME
Cerealus Holdings, LLC
Waterville
ME
|
Family ID: |
43219178 |
Appl. No.: |
12/815334 |
Filed: |
June 14, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11093621 |
Mar 30, 2005 |
7737200 |
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12815334 |
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60582260 |
Jun 23, 2004 |
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Current U.S.
Class: |
252/8.62 |
Current CPC
Class: |
A23V 2002/00 20130101;
D21H 19/14 20130101; D21H 27/10 20130101; A23V 2002/00 20130101;
A23V 2250/5482 20130101; A23V 2250/5086 20130101; A23V 2250/5118
20130101; A23V 2200/22 20130101; A23P 20/20 20160801; A23V 2200/209
20130101; D21H 19/50 20130101; D21H 19/12 20130101 |
Class at
Publication: |
252/8.62 |
International
Class: |
D06M 15/19 20060101
D06M015/19 |
Claims
1. A stable, aqueous barrier composition comprising: (a) prolamine;
(b) cold water insoluble polymer; (c) water; (d) water-soluble
co-solvent; and (e) stabilizer; the composition not requiring an
alcohol for its preparation; and the composition, when applied to a
substrate, producing an article having a high surface energy and
resistance to oil and grease penetration.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation-in-part of pending U.S.
utility application Ser. No. 11/093,621, filed Mar. 30, 2005, which
claims the benefit of U.S. provisional application Ser. No.
60/582,260, filed Jun. 23, 2004, now abandoned.
FIELD OF THE INVENTION
[0002] The present invention relates to barrier compositions, more
particularly to barrier compositions providing resistance to oil
and grease penetration, and to articles which are produced with the
compositions.
TECHNICAL BACKGROUND
[0003] Industry has utilized compounds based on fluorocarbon
chemistry for many years to produce articles having improved
resistance to penetration by oil and grease, due to the ability of
fluorocarbons to lower the surface energy of the articles. One
emerging issue with the use of perfluorinated hydrocarbons is that
they are remarkably persistent in the environment. The EPA and FDA
have recently begun a review of the source, environmental fate, and
toxicity of these compounds. A recent study reported a very high
(>90%) rate of occurrence of perfluorooctane sulfonate in blood
samples taken from school children. The expense and potential
environmental liability of these compounds has driven manufacturers
to seek alternative means of producing articles having resistance
to penetration by oil and grease.
[0004] While lowering the surface energy improves the penetration
resistance of the articles, lowering the surface energy also has
some disadvantages. For example, a textile fabric treated with a
fluorocarbon will exhibit good stain resistance; however, once
soiled, the ability of cleaning compositions to penetrate and hence
release the soil from the fabric, which may result in permanently
soiled fabrics of reduced useful life. Another example is a
greaseproof paper which is to be subsequently printed and or coated
with an adhesive. In this case the requisite grease resistance is
attained by treatment with the fluorocarbon, but the low surface
energy of the paper may cause problems related to printing ink or
adhesive receptivity, including blocking, back trap mottle, poor
adhesion, and register. If a greaseproof paper is to be used as a
release paper having an adhesive applied, the low surface energy
may reduce the strength of the adhesion. To improve their
printability, coatability or adhesion, the low surface energy
articles can be treated by a post forming processes such as corona
discharge, chemical treatment, flame treatment, or the like.
However, these processes increase the cost of producing the
articles and may have other disadvantages.
[0005] Prolamines are proteinaceous compounds present as the
storage proteins of cereal grains. For example, zein is a prolamine
found in corn gluten meal, a by-product of corn milling. Since the
primary use for corn gluten meal is animal feed, which typically
sells for a low price, there has been a great deal of interest in
the development of value added products from zein. Unfortunately,
the suitable applications for zein have been limited due to its
lack of solubility in water.
DESCRIPTION OF PRIOR ART
[0006] Fluorochemicals and other surface modifying compositions are
known for imparting oil and grease resistance to articles. Such
compositions include, for example, compositions of cationic and
non-cationic fluorochemicals (U.S. Pat. No. 4,540,497, Chang et
al), compositions useful in the treatment of articles to impart oil
and grease resistance (PCT Application WO 02/14426, Dixit et al),
fluorinated polymeric paper sizes (U.S. Pat. No. 6,818,717,
Kantamneni), urethane oligomers containing perfluoroalkyl moieties
for imparting water and oil repellency (U.S. Pat. No. 6,803,109,
Qiu et al), compositions for oil and water repellency containing a
polyalkoxylated urethane and a fluorochemical (U.S. Pat. No.
5,725,789, Huber et al), compositions containing a filler material
and wheat gluten (U.S. Pat. No. 6,605,367, Bassi et al), starch and
gelatin surface sizes for oil and grease resistant papers (U.S.
Pat. No. 6,790,270, Billmers et al), and flexible starch films to
impart oil and grease resistance (U.S. Pat. No. 6,649,188,
Gilleland et al). However, these compositions usually suffer from
one or more disadvantages, e.g., they have low surface energy, they
do not provide for a high degree of oil and grease resistance, they
contain fluorocarbons, they are not biodegradable, they contain
high concentrations (>50%) of VOCs, or they are cost prohibitive
on a commercial scale.
[0007] A number of patents relate to compositions containing
prolamines such as zein. For example, U.S. Pat. No. 5,705,207, Cook
et al, discloses a coating/barrier against water, oil and gas,
consisting of a colloidal dispersion of a prolamine-derived protein
and starch in an aqueous acid. Propylene glycol or polyethylene
glycol can be used to plasticize the composition. U.S. Pat. No.
6,231,970, Andersen et al, discloses a thermoplastic starch
composition that can be shaped into articles such as sheet, films
and packaging materials. The composition includes starch, a
protein-based polymer such as zein, and a plasticizer such as
propylene glycol. U.S. Pat. No. 5,705,242, Andersen et al,
discloses food beverage containers made from aggregates held
together by organic binders. The binders can include starch-based
polysaccharides, cellulose-based polysaccharides and/or
prolamines.
[0008] U.S. Pat. No. 6,573,340, Khemani et al, discloses
biodegradable polymer films having good water vapor barrier
properties, which are useful as packaging materials. The films can
include starch, a prolamine, and polyethylene glycol. U.S. Pat. No.
5,356,467, Oshlack et al, discloses aqueous dispersions of zein
which may be used as controlled release coatings for
pharmaceutical, animal, health or food products. The coatings can
also include starch and propylene glycol. U.S. Pat. No. 5,609,909,
Meyer et al, discloses prolamine coatings for orally administered
drugs. The coatings also include a hydrophilic plasticizer such
propylene glycol and/or a non-ionic cellulosic polymer such as
hydroxyethyl cellulose. U.S. Pat. No. 6,844,181, Jabar, Jr.,
discloses a composition used to inhibit fungal growth containing a
peptide such as zein and a polysaccharide such as starch, dissolved
in a water/alcohol solution. A plasticizing agent such as propylene
glycol can also be added.
SUMMARY OF THE INVENTION
[0009] The present invention relates to a stable, aqueous barrier
composition which comprises: (a) prolamine; (b) cold water
insoluble polymer; (c) water; (d) water-soluble co-solvent; and (e)
stabilizer. The composition, when applied to a substrate, produces
an article having a high surface energy and resistance to oil and
grease penetration.
[0010] The invention also relates to a method of producing an
article. The method comprises applying the above-described
composition to a substrate to produce the article which has a high
surface energy and resistance to oil and grease penetration.
[0011] The invention also relates to an article which comprises the
above-described composition applied to a substrate. The article has
a high surface energy and resistance to oil and grease
penetration.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0012] The present invention provides value added products from
zein by overcoming its lack of solubility in water to produce
stable, aqueous barrier compositions. When applied to a substrate,
the compositions produce an article having resistance to oil and
grease penetration. Surprisingly, the compositions achieve these
barrier properties while producing articles having a high surface
energy. As a result, the compositions avoid the disadvantages
associated with the use of barrier compositions that lower the
surface energy of articles. In certain embodiments, the barrier
composition may be characterized as a solution or a stable
suspension and not a latex.
[0013] A barrier composition according to the invention includes
one or more prolamines. Prolamines are proteinaceous compounds
present as the storage proteins of cereal grains, such as corn,
wheat, barley, rice and sorghum. Representative prolamines include,
for example, zein, hordein, gliadin and kafirin. The preferred
prolamine for use in the invention is zein. Zein is available
commercially from various manufacturers, including Freeman
Industries, Tuckahoe, N.Y. and Global Protein Products, Marina,
Calif. In certain embodiments, the prolamine used in the barrier
composition is raw or unmodified, in contrast with prolamines that
are chemically and/or enzymatically altered. For example, fine
milling of the zein is not required. Also, in certain embodiments,
the prolamine is zein having a molecular weight within a range of
from about 15 kd to about 30 kd, more particularly an alpha zein
having a molecular weight within a range of from about 19 kd to
about 24 kd. Further, in certain embodiments, the three-dimensional
properties of the zein are relevant to the film forming ability of
the barrier composition; for example, the zein may be in alpha
helix configuration rather than beta sheet. The prolamine can be
included in the composition in any suitable amount. In certain
embodiments, the prolamine is included in an amount within a range
of from 1 wt % to about 10 wt %, and more particularly from about 2
wt % to about 5 wt %.
[0014] The barrier composition also includes one or more cold water
insoluble polymers. By "cold water insoluble" is meant that the
polymer is insoluble in water at temperatures of 75.degree. F.
(24.degree. C.) or below. The polymer may be soluble or insoluble
at higher temperatures. Water solubility, as defined herein, is
tested as follows. A 1 g sample of the polymer is provided. The
sample is added to a flask containing 100 mL of distilled water
held at a temperature of 75.degree. F. The flask is subjected to
vigorous stirring or shaking for one minute(s), and then held still
for 60 minute(s). If any precipitation of the polymer has occurred,
the supernatant is poured from the flask and the precipitate is
collected and weighed. The polymer is considered to be water
soluble if not more than 5 wt % of the polymer precipitates.
[0015] The composition can include any type of cold water insoluble
polymer suitable for combining with the other components to produce
the stable barrier composition. Preferably, the polymer is a
polysaccharide. Some examples of suitable polysaccharides include
starches, starch derivatives, modified starches, thermoplastic
starches, starch esters, such as starch acetate, starch
hydroxyethyl ethers, alkyl starches, dextrins, amine starches,
phosphate starches, and dialdehyde starches. The starch can be
cationic, anionic, amphoteric, or non-ionic. Preferably, the starch
is non-ionic. The starch derivatives include carboxymethylstarch,
hydroxyethylstarch, hydroxypropylstarch,
carboxymethylhydroxypropylstarch, and oxidized starch.
[0016] Some other examples of cold water insoluble polymers include
synthetic polymers such as polyethylene, high density polyethylene,
low density polyethylene, linear low density polyethylene, ultralow
density polyethylene, polyolefins, poly(ethylene-co-methyl
acrylate), poly(ethylene-co-ethyl acrylate), poly(ethylene-co-butyl
acrylate), poly(ethylene-co-(meth)acrylic acid), metal salts of
poly(ethylene-co-(meth)acrylic acid), poly((meth)acrylates), such
as poly(methyl methacrylate), poly(ethyl methacrylate), and the
like, poly(vinyl acetate), poly(ethylene-co-vinyl acetate),
poly(vinyl alcohol), poly(ethylene-co-vinyl alcohol),
polypropylene, polybutylene, polyesters, poly(ethylene
terephthalate), poly(1,3-propyl terephthalate), poly(1,4-butylene
terephthalate), poly(vinyl chloride), PVDC, poly(vinylidene
chloride), polystyrene, polyamides, nylon, nylon 6, nylon 46, nylon
66, nylon 612, polycarbonates, polysulfides, polyethers,
polysulfones, and the like, and copolymers thereof.
[0017] The composition can contain any suitable amount of water. In
certain embodiments, the composition contains water in an amount
within a range of from about 30 wt % to about 90 wt %, more
particularly about 40 wt % to about 85 wt %, and most particularly
about 50 wt % to about 80 wt %.
[0018] The barrier composition also includes one or more
water-soluble co-solvents. Preferably, the co-solvent is soluble in
both aqueous and nonaqueous solvents. The co-solvent is usually
multifunctional, i.e. it serves as co-solvent for the prolamine and
as a plasticizer for the film formed from the aqueous composition.
Any suitable type of co-solvent can be used in the composition.
Preferably, the co-solvent is a glycol, such as propylene glycol,
ethylene glycol, diethylene glycol, triethylene glycol, or
diethylene glycol monobutyl ether. Other examples of suitable
co-solvents include diethanolamine, and glycerol. In certain
embodiments, the co-solvent excludes a monohydric alcohol, and also
in certain embodiments it excludes a ketone such as acetone. In
other embodiments, these materials are included in amounts no
greater than 10 wt %, and more particularly no greater than 5 wt %.
The co-solvent can be included in any suitable amount in the
composition. In certain embodiments, the composition includes
co-solvent in an amount within a range of from about 5 wt % to
about 60 wt %, more particularly from about 10 wt % to about 50 wt
%, and most particularly from about 20 wt % to about 45 wt %. The
amount of water in the composition is usually greater than the
amount of co-solvent, so that the primary solvent of the
composition is water.
[0019] The barrier composition further includes one or more
stabilizers that, in combination with the other components of the
composition, produce a stable aqueous composition as described more
fully below. Any type of material suitable for stabilizing the
composition can be used. When the cold water insoluble polymer is a
starch, preferably the stabilizer bears an anionic charge. In such
a case, a preferred stabilizer is a cellulose derivative, such as
carboxymethylcellulose, hydroxyethyl-cellulose, methylcellulose,
ethylcellulose, hydroxyethylpropylcellulose,
methyl-hydroxypropylcellulose, or
carboxymethylhydroxyethylcellulose. In certain embodiments, the
barrier composition includes the combination of a starch and a
cellulose derivative.
[0020] Other examples of suitable stabilzers include gums such as
xanthan gum, guar gum and its derivatives, gum arabic, acaia gum,
carrageenan gum, furcellaran gum, ghatti gum, locust bean gum, gum
karaya, and gum tragacanth
[0021] Other stabilizers can include polymeric or surfactant
species such as polyacrylates, polyoxyethylene sorbitan mono-oleate
(e.g., Tween 20 or Tween 80), other glycerides preferably those
derivatives of fatty acids in the C.sub.8-C.sub.20 range, sodium
lauryl sulfate and cetyltrimethylammonium bromide. Other
stabilizers can be inorganic steric stabilizers such as magnesium
carbonate, magnesium sulfate and magnesium silicate. Additionally
the stabilizers can include functional agents such as water
repellant agents inlcuing alkenyl succinic anhydride (ASA), alkyl
ketene dimmer (AKD), styrene maleic anhydride, octynl succinic
anhydride, rosin, rosin derivatives, styrene acrylic acetates,
styrene acrylic emulsions, polyurethane dispersions, wax
dispersions, and the like.
[0022] The stabilizer can be included in any amount suitable for
providing a stable aqueous composition. Generally, the stabilizer
is included in an amount within a range of from about 0.01 wt % to
about 10 wt % of the composition, and usually from about 0.01 wt %
to about 5 wt %.
[0023] In addition to the above-described components, the
composition can optionally contain one or more additives to enhance
various properties of the composition, so long as the stability of
the composition and the barrier properties are maintained. For
example, suitable additives may include various dispersants,
vehicles, leveling agents, defoamers, antifoamers, antimicrobials,
or pigments.
[0024] In some embodiments of the invention, the barrier
composition "consists essentially of" the prolamine, cold water
insoluble polymer, water, water-soluble co-solvent, and stabilizer.
In other words, the barrier composition excludes other components
of any essential significance to the composition.
[0025] In contrast to compositions such as those disclosed in U.S.
Pat. No. 5,705,207 to Cook et al, the barrier composition does not
require the use of an acid as a component. In some embodiments, the
barrier composition excludes more than about 5 wt % acid, more
particularly it contains not more than 2 wt % acid, more
particularly not more than 1 wt %, and most particularly and it
contains substantially no acid.
[0026] The barrier composition is a stable aqueous composition,
"stable aqueous composition" is defined as an aqueous composition
which is substantially resistant to viscosity change, coagulation,
precipitation, and sedimentation over at least an 8-hour period
when contained in a closed vessel and stored at a temperature in a
range of from about 0.degree. C. to about 60.degree. C. Some
embodiments of the composition are stable over at least a 24-hour
period, and often over at least a 6-month period.
[0027] The barrier composition, when applied to a substrate,
produces an article having a high surface energy. As used herein,
"high surface energy" refers to an article having a surface energy
of at least about 32 dynes/cm, and commonly at least about 36
dynes/cm. Surface energy can be measured by any suitable method,
for example by contact angle measurement and the relationship
between surface energies using Young's Equation, as described below
in Example 1.
[0028] Importantly, the barrier composition, when applied to a
substrate, also produces an article having resistance to oil and
grease penetration. Resistance to oil and grease penetration
includes resistance to penetration by various oils, greases, waxes,
other oily substances and surprisingly highly penetrating solvents
like toluene and heptane. The resistance to oil and grease
penetration may be measured by the 3M Kit Test, which is described
below in Example 2. The Kit number may also be measured according
to a standard Tappie method. Preferably, the composition has a Kit
number of at least 3, more preferably at least 5, more preferably
at least 7, and most preferably at least 9.
[0029] The barrier composition can be produced by any suitable
method. In certain embodiments, the composition is produced without
the use of a monohydric alcohol such as ethanol. The preparation of
the composition may include a dihydric alcohol such as a glycol, or
in certain embodiments the composition may be prepared without
using any type of alcohol. Further, in certain embodiments, the
barrier composition is produced without a hazardous or high VOC
material.
[0030] In certain embodiments, the order of addition of the
components is relevant for producing the barrier composition. For
example, first the zein is dissolved in the glycol. Then a
stabilizer such as a cellulose derivative is mixed with the zein
and glycol. Then the water is added to the mixture of zein and
stabilizer in glycol. The water is added to this mixture, and not
the other way around (i.e., the mixture of zein, stabilizer and
glycol are not added to the water).
[0031] In certain embodiments, the barrier composition can be
produced without the need for filtering the product.
[0032] A method of producing an article according to the invention
comprises applying the barrier composition to a substrate to
produce the article which has a high surface energy and resistance
to oil and grease penetration. The barrier composition is provided
in intimate contact with one or more surfaces of the substrate in
order to provide penetration resistance to those surfaces. The
barrier coating can be applied as a coating on the one or more
surfaces, or in some applications it can be applied such that it is
absorbed into the interior of substrate and contacts one or more
surfaces.
[0033] In a preferred embodiment, the barrier composition is
applied as a coating on the substrate. The substrate can be coated
with the composition by any suitable method, for example, by
rolling, spreading, spraying, brushing, or pouring processes,
followed by drying, by co-extruding the barrier composition with
other materials onto a preformed substrate, or by melt/extrusion
coating a preformed substrate. The substrate can be coated on one
side or on both or all sides with the barrier composition. A
coating knife, such as a "doctor blade", allows uniform spreading
of the barrier composition onto a substrate that is moved along by
rollers. The composition is then dried. For example, U.S. Pat. No.
3,378,424 discloses processes for coating a fibrous substrate with
an aqueous polymeric emulsion. Coatings can be applied to textiles,
non-wovens, foil, paper, paperboard, and other sheet materials by
continuously operating spread-coating machines.
[0034] The amount of barrier composition applied to the substrate
can vary depending on the application. In certain embodiments, the
application rate of the composition is within a range of from about
1 gram/square meter to about 10 grams/square meter (dry coat
weight), and more particularly from about 3 grams/square meter to
about 8 grams/square meter. Also, in certain embodiments, the dry
coating has a substantially uniform thickness throughout the area
of the coating. Further, in certain embodiments, the composition
produces a substantially continuous film on the substrate. The
substrate may be completely covered by the coating or only a
portion covered.
[0035] After application to the substrate, the barrier composition
can be dried either with or without the application of heat to
produce a film or coating on the substrate.
[0036] The barrier compositions of the invention can be used to
produce a wide variety of different articles having resistance to
oil and grease penetration. The articles can include, for example,
paper, paperboard, cardboard, containerboard, gypsum board, wood,
wood composites, furniture, masonry, leather, automobile finishes,
furniture polishes, plastics, non-stick cookware, and foams.
[0037] A particularly preferred use for the barrier compositions is
food packaging papers and paperboard, especially fast food
packaging. Specific examples of food packaging uses include fast
food wrappers, food bags, snack bags, grocery bags, cups, trays,
cartons, boxes, bottles, crates, food packaging films, blister pack
wrappers, microwavable popcorn bags, release papers, pet food
containers, beverage containers, OGR papers, and the like. In
another preferred embodiment, textile articles are produced, such
as natural textile fibers or synthetic textile fibers. The textile
fibers can be further processed into garments, linens, carpets,
draperies, wall-coverings, upholstery and the like.
[0038] Substrates can be formed into articles prior to or after
applying the barrier composition. For example, containers can be
produced from flat, coated paperboard by press-forming, by vacuum
forming, or by folding and adhering them into the final desired
shape. Coated, flat paperboard stock can be formed into trays by
the application of heat and pressure, as disclosed within, for
example, U.S. Pat. No. 4,900,594, or vacuum formed into containers
for foods and beverages, as disclosed within U.S. Pat. No.
5,294,483.
Example 1
Contact Angle Studies
[0039] This example describes how surface energy can be measured
according to the invention. Contact angle measurements allow us to
determine a relationship between surface energies of different
materials. Young's Equation allows us to relate these
quantities:
.gamma.lv(COS .theta.)=(.gamma.sv-.gamma.sl)
[0040] Here, .gamma.sv represents the interface between the solid
substrate and the vapor. For our purposes it is considered to be
zero. .gamma.lv=the surface energy between the liquid and the
vapor. The constant used for this water/air interaction is 72.94
dynes/cm. The contact angle gives us .theta., and we solve for
.gamma.sl which is the surface energy between the solid liquid
interface. Table 1 below lists the surface energies of some barrier
compositions according to the invention and also the surface
energies of several other substances.
TABLE-US-00001 TABLE 1 Surface Energy Coating type Contact angle
(approx.) dyne/cm Fluorocarbon 105.11, 104.6 19.02 Fluorocarbon
106.24, 108.96 20.40 Pure Prolamine film 54.67, 54.78 42.18 (PG
solvent) Pure Prolamine film 63.65, 62.35 32.39 (PG solvent) Pure
Prolamine film 59.75, 65.96 36.75 (Ethanol solvent) Pure Prolamine
film 61.36, 60.55 34.96 (Ethanol solvent) Polyvinyl Alcohol 62.63,
60.78 33.53 (Airvol 425) Polyvinyl Alcohol 60.71, 64.36 35.68
(Airvol 425) Invention 50.10, 51.69 46.78 Composition Invention
41.27, 46.52 54.82 Composition
[0041] The barrier compositions of the invention are compositions A
and B described below in Example 3. The fluorocarbon is a 5% w/w
aqueous composition. The pure prolamine film made with propylene
glycol (PG) solvent is 5% w/w zein, and the pure prolamine film
made with ethanol solvent is 5% w/w. The polyvinyl alcohol is 4%
w/w aqueous composition. The invention compositions were 5% w/w
zein. All composition were cast on glass, dried at 100.degree. C.
for 60 minutes and evaluated for contact angle.
Example 2
3M Kit Test
[0042] The 3M Kit test can be used to measure the resistance to
oil, grease, and solvent penetration of articles produced with the
barrier compositions of the invention.
[0043] Kit solutions are prepared as follows:
TABLE-US-00002 Volume of Castor Oil Volume of Toluene Volume of
Heptane Kit # (ml) (ml) (ml) 1 200 0 0 2 180 10 10 3 160 20 20 4
140 30 30 5 120 40 40 6 100 50 50 7 80 60 60 8 60 70 70 9 40 80 80
10 20 90 90 11 0 100 100 12 0 90 110
[0044] An article is placed on a clean flat, surface and a drop of
test solution is released from a height of 25 mm onto a surface of
the article to which the barrier composition has been applied.
After 15 seconds, the excess fluid is removed with a cotton swatch
or a tissue and the wetted area is examined. A pronounced darkening
of the article denotes a failure. The Kit Rating is the highest
numbered solution that stands on the surface of the article without
causing failure. Table 2 below shows the Kit Ratings of various
compositions.
TABLE-US-00003 TABLE 2 Kit Ratings of Various Compositions Concen-
Kit Additive tration achieved Notes ASA (alkenyl 5%-8%.sup. 11
Stable, creamy succinic anhydride) Xanthan Gum 1-2% 9 Stable,
creamy, thick Tween 20 1-2% 8 Stable Tween 80 1-2% 11 Stable Sodium
Carbonate 2% Formulation unstable Potassium Hydroxide <1% 5 pH
8.3 Formulation unstable Carboxymethylcellu- 1-3% 12 Stable over
time, lower lose, Sodium salt viscosity than xgum
[0045] Base composition of 4% zein, 9.6% ethylated starch, 70.4%
water, 14.5% propylene glycol
Example 3
Examples of Barrier Compositions
[0046] Compositions according to the present invention were
formulated as follows: A creamy flowable composition was produced
and coated onto paper stock. The paper stock was subsequently dried
and tested using the 3M Kit procedure.
TABLE-US-00004 Composition A B C D E 1) zein 2.5% 1.0% 2.5% 2.5%
1.0% 2) ethylated starch 6.0% 6.0% 9.0% 7.2% 10.8% 3) water 50% 50%
66% 52.8% 79% 4) propylene glycol 41.3% 43.0% 22.5% 16% 9% 5)
xanthan gum 0.2% 0 0 0 0.2% 6) Alkyl succinic 0 0 0 21.5 0
anhydride 3M Kit Response 9 3 6 11 5
[0047] In accordance with the provisions of the patent statutes,
the principle and mode of operation of this invention have been
explained in its preferred embodiments. However, it must be
understood that this invention may be practiced otherwise than as
specifically explained without departing from its spirit or
scope.
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