U.S. patent application number 11/072834 was filed with the patent office on 2005-09-08 for barrier coating comprising a polyurethane dispersion.
Invention is credited to Faler, Dennis L., Kasper, Walter F., Miles, Michelle S., Nguyen, Diep, Temple, Rodger G., Woodworth, Brian E..
Application Number | 20050197481 11/072834 |
Document ID | / |
Family ID | 34963582 |
Filed Date | 2005-09-08 |
United States Patent
Application |
20050197481 |
Kind Code |
A1 |
Temple, Rodger G. ; et
al. |
September 8, 2005 |
Barrier coating comprising a polyurethane dispersion
Abstract
A barrier coating comprising a polyurethane dispersion is
disclosed. The polyurethane comprises at least 30 weight percent of
meta-substituted aromatic material. Methods for improving barrier
using the coatings are also disclosed.
Inventors: |
Temple, Rodger G.; (Sarver,
PA) ; Faler, Dennis L.; (Glenshaw, PA) ;
Nguyen, Diep; (Wexford, PA) ; Woodworth, Brian
E.; (Pittsburgh, PA) ; Kasper, Walter F.;
(Gibsonia, PA) ; Miles, Michelle S.; (Mercer,
PA) |
Correspondence
Address: |
PPG INDUSTRIES, INC.
Intellectual Property Department
One PPG Place
Pittsburgh
PA
15272
US
|
Family ID: |
34963582 |
Appl. No.: |
11/072834 |
Filed: |
March 4, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60550491 |
Mar 5, 2004 |
|
|
|
Current U.S.
Class: |
528/83 |
Current CPC
Class: |
C08G 18/12 20130101;
Y10T 428/31573 20150401; Y10T 428/28 20150115; Y10T 428/249953
20150401; Y10T 428/31551 20150401; C08G 18/12 20130101; C08G
18/3237 20130101; C08G 18/3271 20130101; C08G 18/3215 20130101;
C08G 18/12 20130101; C09D 175/04 20130101; Y10T 428/31583 20150401;
C08G 18/4205 20130101; C08G 18/6659 20130101; C08G 18/3829
20130101; C08G 18/0823 20130101; C08G 18/12 20130101; C08G 18/4222
20130101 |
Class at
Publication: |
528/083 |
International
Class: |
C08G 018/30 |
Claims
What is claimed is:
1. A barrier coating comprising a polyurethane dispersion
comprising at least 30 weight percent of meta-substituted aromatic
material.
2. The coating of claim 1, wherein the meta-substituted aromatic
material comprises TDI, HER, MXDA, TMXDI and/or isophthalic
acid.
3. The coating composition of claim 1, wherein the polyurethane
dispersion is water-based.
4. The coating composition of claim 1, wherein the polyurethane
dispersion is solvent-based.
5. The coating composition of claim 1, wherein the polyurethane
dispersion comprises a polyester polyol.
6. The coating of claim 1, wherein the polyurethane has a Molar
Permachor Number of at least 50.
7. The coating of claim 1, further comprising a crosslinker.
8. The coating of claim 7, wherein the crosslinker comprises
aziridine.
9. The coating of claim 1, wherein the polyurethane dispersion
comprises a blend of two or more polyurethane dispersions.
10. The coating of claim 1, further comprising one or more
polymers.
11. The coating of claim 10, wherein the one or more polymers
imparts additional barrier to the coating.
12. The coating of claim 11, wherein one of the polymers is
polyvinylidene chloride and/or copolymers comprising polyvinylidene
chloride.
13. The coating of claim 1, further comprising a colorant.
14. The coating of claim 1, further comprising a high aspect ratio
pigment.
15. The coating of claim 13, wherein the colorant is a polyester
nylon composite.
16. A barrier coating having a Molar Permachor Number of at least
50.
17. A method for improving barrier on the substrate, comprising
applying to the substrate the coating of claim 1.
18. The method of claim 17, wherein the substrate is a flexible
substrate.
19. The method of claim 17, wherein the substrate is an elastic
substrate.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to provisional application
No. 60/550,491, filed Mar. 5, 2004.
FIELD OF THE INVENTION
[0002] The present invention relates to barrier coatings comprising
a polyurethane dispersion.
BACKGROUND INFORMATION
[0003] For many substrates used in a variety of industries, barrier
protection, such as protection against vapor, gas and/or chemical
ingress and/or egress, is often desired. For example, thermoplastic
and thermoset polymeric materials are widely used substrates
through which gases, such as oxygen and carbon dioxide, can be
readily permeated. This is particularly true of most of the plastic
materials commonly used by the packaging industry. Some
oxygen-sensitive products may become discolored and/or spoiled upon
even minute exposure to oxygen, and carbonated beverages can lose
their carbonation or become "flat" if carbon dioxide is removed.
Bladders, such as those used in sporting equipment including shoes
and balls, are similarly permeable to gas. The materials used in
tires are also permeable to gas, and resistance to gas and moisture
permeation is typically desired. Often, coatings used for
increasing the barrier of these substrates can have a negative
effect on the flexibility and/or elasticity of the substrate.
Improved barrier coatings, particularly those in which flexibility
and/or elasticity are not significantly sacrificed, are therefore
desired.
SUMMARY OF THE INVENTION
[0004] The present invention is directed to a barrier coating
comprising a polyurethane comprising at least 30 weight percent of
meta-substituted aromatic material. The present invention is
further directed to methods for using the barrier coatings
described herein.
DETAILED DESCRIPTION OF THE INVENTION
[0005] The present invention is directed to a barrier coating
comprising a polyurethane comprising at least 30 weight percent of
meta-substituted aromatic material. The weight percent is based on
the total solid weight of the resin. "Polyurethane" as used herein
refers to compounds having urethane and/or urea linkages.
[0006] As used herein, "barrier coating" refers to a coating that
imparts vapor barrier, gas barrier and/or chemical barrier to a
substrate. "Vapor barrier" refers to a barrier and/or low
permeability to liquid and/or its vapor. "Gas barrier" refers to a
barrier or low permeability to oxygen, nitrogen, carbon dioxide
and/or other gases. "Chemical barrier" refers to a barrier or low
permeability to the migration of a molecule from one substrate to
another, and/or from within one substrate to its surface. Any
resistance to permeation of vapor, gas and/or chemical(s) is
sufficient to qualify the coating as a "barrier coating" according
to the present invention. The gas barrier properties of a
substrate, and/or any coatings thereon, are typically described in
terms of the oxygen permeability constant ("P(O.sub.2)"). The
"P(O.sub.2)" number quantifies the amount of oxygen that can pass
through a substrate and/or coating under a specific set of
circumstances and is generally expressed in units of
cm.sup.3-mil/100 inches.sup.2/atmosphere/day. This is a standard
unit of permeation measured as cubic centimeters of oxygen
permeating through one mil (25.4 micron) thickness of a sample, 100
square inches (654 square centimeters) in an area, over a 24-hour
period, under a partial pressure differential of one atmosphere at
a specific temperature and relative humidity (R.H.) conditions.
[0007] As noted above, at least 30 weight percent of the
polyurethane used in the present barrier coating is
meta-substituted aromatic material. The meta-substituted aromatic
material can be introduced through components of the polyurethane
pre-polymer, or through chain extenders reacted with the
polyurethane. Components that contribute barrier may have a
negative effect on flexibility and/or elasticity of a substrate;
the needs of the user will help to determine the desired level of
barrier, flexibility and/or elasticity. The percent of
meta-substituted aromatic material can be determined, for example,
by adding the weight of all the monomers containing
meta-substituted aromatic material, dividing that number by the
total solid weight of the final resin and multiplying by 100.
[0008] In one embodiment of the present invention, the polyurethane
comprises a polyester polyol. In another embodiment of the present
invention, the polyester polyol has a Molar Permachor Number of at
least 35, such as 39 or higher. "Molar Permachor Number" and like
terms refer to the number calculated from the chemical structure of
the polymer; each atom or group of atoms in side chains or the
backbone has a value from the Master Table of Segmental Permachor
Values, which Table can be found, for example, in "Properties of
Polymers" by D. W. Van Krevelan, 3.sup.rd Ed., Elsevier, (1990).
The values are then used to get the Permachor Number, according to
methods known to those skilled in the art, which are also discussed
in "The Use of Barrier Polymers in Packaging" by Morris Salame,
Polysultants Co.
[0009] In certain nonlimiting embodiments of the invention, the
polyester polyol Molar Permachor Number of at least 35 is achieved
by preparing a polyester polyol from a polyol comprising an ether
moiety and a carboxylic acid or anhydride. Suitable ether polyols
include, for example, diethylene glycol, ethylene glycol and lower
oligomers of ethylene glycol including diethylene glycol,
triethylene glycol and tetraethylene glycol; propylene glycol and
lower oligomers of propylene glycol including dipropylene glycol,
tripropylene glycol and tetrapropylene glycol; also
poly(tetrahydrofuran). Suitable dicarboxylic acids include but are
not limited to glutaric acid, succinic acid, malonic acid, oxalic
acid, phthalic acid, isophthalic acid, hexahydrophthalic acid,
adipic acid, maleic acid, and mixtures thereof. Anhydrides of these
and any other carboxylic acids can also be used. In certain
nonlimiting embodiments, the polyester polyol has greater than
eight carbon atoms.
[0010] The polyester polyol can be prepared according to any method
known in the art. For example, the polyol and carboxylic
acid/anhydride can be heated together while removing the water
generated by esterification until a desired acid number is
achieved.
[0011] The polyester polyol can then be reacted with isocyanate to
form a polyurethane. The polyurethane can be formed according to
any method known in the art, such as by heating the polyol with an
isocyanate until a desired NCO equivalent weight is achieved. Any
isocyanate can be used according to the present invention; examples
include, but are not limited to, isophorone diisocyanate (IPDI),
dicyclohexylmethane 4,4'-diisocyanate (H.sub.12MDI), cyclohexyl
diisocyanate (CHDI), m-tetramethylxylylene diisocyanate (m-TMXDI),
p-tetramethylxylylene diisocyanate (p-TMXDI), ethylene
diisocyanate, 1,2-diisocyanatopropane, 1,3-diisocyanatopropane,
1,6-diisocyanatohexane (hexamethylene diisocyanate or HDI),
1,4-butylene diisocyanate, lysine diisocyanate, 1,4-methylene
bis-(cyclohexyl isocyanate), toluene diisocyanate (TDI),
m-xylylenediisocyanate (MXDI) and p-xylylenediisocyanate,
4-chloro-1,3-phenylene diisocyanate, 1,5-tetrahydro-naphthalene
diisocyanate, 4,4'-dibenzyl diisocyanate, and 1,2,4-benzene
triisocyanate, xylylene diisocyanate (XDI), and combinations
thereof.
[0012] The polyurethane can then be chain extended to build
molecular weight using, for example, any chain extension agent
having more than one reactive functional group. Examples include
polyols, polyamines, polythiols, or other compounds having reactive
functional groups, such as hydroxy groups, thiol groups, amine
groups, carboxylic acids, and acetylacetonate protons. Suitable
polyol chain extenders include, but are not limited to:
1,6-hexanediol; cyclohexanedimethanol; 2-ethyl-1,6-hexanediol;
1,4-butanediol; ethylene glycol and lower oligomers of ethylene
glycol including diethylene glycol, triethylene glycol and
tetraethylene glycol; propylene glycol and lower oligomers of
propylene glycol including dipropylene glycol, tripropylene glycol
and tetrapropylene glycol; 1,3-propanediol; 1,4-butanediol;
neopentyl glycol; dihydroxyalkylated aromatic compounds such as the
bis (2-hydroxyethyl) ethers of hydroquinone and resorcinol (HER);
p-xylene-a, a'-diol; the bis (2-hydroxyethyl) ether of p-xylene-a,
a'-diol; m-xylene-a, a'-diol and the bis (2-hydroxyethyl) ether,
trimethylol propane, 1,2,6-hexantriol, glycerol, and mixtures
thereof. Suitable polyamine extenders include, but are not limited
to, p-phenylenediamine, m-phenylenediamine, benzidine,
4,4'-methylenedianiline, 4,4'-methylenibis (2-chloroaniline),
ethylene diamine, m-xylylenediamine (MXDA) and combinations of
these. Other typical chain extenders are amino alcohols such as
ethanolamine, propanolamine, and butanolamine. Acidic chain
extenders include 2,2-bis(hydroxymethyl)propionic acid (DMPA),
2,2-bis(hydroxymethyl)butyri- c acid, and diphenolic acid. Other
suitable chain extenders and combinations of chain extenders are
also within the scope of the present invention.
[0013] Isocyanates can also be used, such as any of those listed
above, to further chain extend the molecule and/or impart desired
properties.
[0014] Chain extension can be accomplished by means standard in the
art. For example, the chain extenders can be heated in a flask and
the polyurethane added thereto. In certain nonlimiting embodiments,
it may be desired to neutralize a chain extended polyurethane
having acidic functionality to increase stability of the
polyurethane when it is dispersed in water. Any amine or other
neutralizing agent can be used; certain chain extenders may also
provide neutralization. Examples include but are not limited to
MXDA and dimethylethanol amine (DMEA); the neutralizing agent can
also contribute to the barrier properties of the coating. In
certain nonlimiting embodiments, the polyurethane is in solvent,
and neutralization of any acid in the polyurethane molecule is not
desired.
[0015] As noted above, the polyurethanes used in the coatings of
the present invention comprise at least 30 weight percent of
meta-substituted aromatic material. Weight percent is based on the
total solid weight of the resin (i.e. polyurethane) itself. The
meta-substituted aromatic material can be introduced in the
polyester polyol, the isocyanate reacted with the polyester polyol
to form the urethane, and/or any of the various chain
extenders.
[0016] The polyurethane prepolymer of the present invention will
typically have a weight average molecular weight in THF of 5000 to
30,000, such as 7000 to 25,000 or 10,000 to 15,000. The
polyurethane when dispersed in water (i.e. the "polyurethane
dispersion") will typically have a weight average molecular weight
(in DMF) of 8000 to 200,000, such as 10,000 to 130,000 or 20,000 to
60,000. In certain nonlimiting embodiments, the polyurethane will
have a Molar Permachor Number of at least 50.
[0017] In certain nonlimiting embodiments, it may be desired to use
a meta-substituted aliphatic isocyanate, such as TMXDI, to form the
polyurethane.
[0018] In certain nonlimiting embodiments, the polyurethane
dispersion is comprised of a blend of two or more different
polyurethanes. In these embodiments, there will be at least 30
weight percent of meta-substituted aromatic material based on the
overall weight of polyurethane in the blend, but each polyurethane
added to the blend may or may not have at least 30 weight percent
of meta-substituted aromatic material. For example, a first
polyurethane dispersion having approximately 35 weight percent TDI
and approximately 20 weight percent HER can be blended with a
second polyurethane dispersion comprising approximately 20 weight
percent TDI and zero percent HER.
[0019] In certain nonlimiting embodiments, the barrier coating of
the present invention further comprises one or more additional
polymers. The polymer(s) can be chosen to impart various properties
and/or effects to the coating. For example, a polymer known to
impart barrier can be used, such as polyvinylidene chloride (PVDC),
copolymers of vinylidene chloride, EVOH, polyamides, and the like.
Other polymers that function as adhesion promoters, flexibilizers,
plasticizers and the like can also be used.
[0020] In certain nonlimiting embodiments, the present barrier
coatings further comprise a pigment or other colorant. As used
herein, the term "colorant" means any substance that imparts color
and/or other opacity and/or other visual effect to the composition.
The colorant can be added to the coating in any suitable form, such
as discrete particles, dispersions, solutions and/or flakes. A
single colorant or a mixture of two or more colorants can be used
in the coating of the present invention.
[0021] Example colorants include pigments, dyes and tints, such as
those used in the paint industry and/or listed in the Dry Color
Manufacturers Association (DCMA) as well as special effect
compositions. A colorant may include, for example, a finely divided
solid powder that is insoluble but wettable under the conditions of
use. A colorant can be organic or inorganic and can be agglomerated
or non-agglomerated.
[0022] As noted above the colorant can be in the form of a
dispersion including, but not limited to, a nanoparticle
dispersion. Nanoparticle dispersions can include one or more highly
dispersed nanoparticle colorants or colorant particles that produce
a desired visible color and/or opacity and/or visual effect.
Nanoparticle dispersions can include colorants such as pigments or
dyes having a particle size of less than about 150 nm, such as less
than 70 nm, or less than 30 nm. Example nanoparticle dispersions
and methods for making them are identified in U.S. Application
Publication No. 2003/0125417, which is incorporated herein by
reference. Nanoparticle dispersions can also be produced by
crystallization, precipitation, gas phase condensation, and
chemical attrition (i.e., partial dissolution). In order to
minimize re-agglomeration of nanoparticles within the coating, a
dispersion of resin-coated nanoparticles can be used. As used
herein, a "dispersion of resin-coated nanoparticles" refers to a
continuous phase in which is dispersed discreet "composite
microparticles" that comprise a nanoparticle and a resin coating on
the nanoparticle. Example dispersions of resin-coated nanoparticles
and methods for making them are identified in U.S. application Ser.
No. 10/876,315 filed Jun. 24, 2004, which is incorporated herein by
reference, and U.S. Provisional Application No. 60/482,167 filed
Jun. 24, 2003, which is also incorporated herein by reference.
[0023] Example special effect compositions that may be used in the
coating of the present invention include pigments and/or
compositions that produce one or more appearance effects such as
reflectance, pearlescence, metallic sheen, phosphorescence,
fluorescence, photochromism, photosensitivity, thermochromism,
goniochromism and/or color-change. Additional special effect
compositions can provide other perceptible properties, such as
opacity or texture. In a non-limiting embodiment, special effect
compositions can produce a color shift, such that the color of the
coating changes when the coating is viewed at different angles.
Example color effect compositions are identified in U.S. Patent
Application Publication No. 2003/0125416, incorporated herein by
reference. Additional color effect compositions can include
transparent coated mica and/or synthetic mica, coated silica,
coated alumina, a transparent liquid crystal pigment, a liquid
crystal coating, and/or any composition wherein interference
results from a refractive index differential within the material
and not because of the refractive index differential between the
surface of the material and the air.
[0024] In certain non-limiting embodiments, a photosensitive
composition and/or photochromic composition, which reversibly
alters its color when exposed to one or more light sources, can be
used in the coating of the present invention. Photochromic and/or
photosensitive compositions can be activated by exposure to
radiation of a specified wavelength. When the composition becomes
excited, the molecular structure is changed and the altered
structure exhibits a new color that is different from the original
color of the composition. When the exposure to radiation is
removed, the photochromic and/or photosensitive composition can
return to a state of rest, in which the original color of the
composition returns. In one non-limiting embodiment, the
photochromic and/or photosensitive composition can be colorless in
a non-excited state and exhibit a color in an excited state. Full
color-change can appear within milliseconds to several minutes,
such as from 20 seconds to 60 seconds. Example photochromic and/or
photosensitive compositions include photochromic dyes.
[0025] In a non-limiting embodiment, the photosensitive composition
and/or photochromic composition can be associated with and/or at
least partially bound to, such as by covalent bonding, a polymer
and/or polymeric materials of a polymerizable component. In
contrast to some coatings in which the photosensitive composition
may migrate out of the coating and crystallize into the substrate,
the photosensitive composition and/or photochromic composition
associated with and/or at least partially bound to a polymer and/or
polymerizable component in accordance with a non-limiting
embodiment of the present invention, have minimal migration out of
the coating. Example photosensitive compositions and/or
photochromic compositions and methods for making them are
identified in U.S. application Ser. No. 10/892,919 filed Jul. 16,
2004 and incorporated herein by reference. Composite
polyester/nylon pigments, for example, can be incorporated into the
present coatings and provide, for example, a good appearance
without affecting flexibility; such pigments can also contribute to
barrier. Suitable polyester/nylon pigments are commercially
available from Teijin Fiber Limited, Osaka, Japan.
[0026] In certain nonlimiting embodiments, the pigment can be one
having a high aspect ratio. Suitable high aspect ratio pigments
include, for example, vermiculite, mica, talc, metal flakes, platy
clays and platy silicas. High aspect ratio platelets or pigments
may be present in coatings in amounts from above 0.1 to 20 weight
percent of the barrier coating, such as from 1 to 10 weight
percent, with weight percent based on the total solid weight of the
coating. The high aspect ratio pigments may form a "fish-scale"
arrangement within the coating, which provides a tortuous path for
gases to pass through from one side of the coating to the other.
Such platelets typically have diameters of from about 1 to about 20
microns, such as about 2 to 5 or 10 microns. The aspect ratio of
the platelets is typically at least 5:1, such as at least 10:1 or
20:1. As particular examples, mica flakes may have an aspect ratio
of about 20:1, talc may have an aspect ratio of about 10:1 to about
20:1 and vermiculite may have an aspect ratio of from about 200:1
to about 10,000:1. While high aspect ratio pigments contribute to
barrier properties, if used in quantities that are too great,
flexibility and/or elasticity may be sacrificed. Accordingly, the
user will need to determine the appropriate amount of high aspect
ratio pigment to use to get the desired properties of barrier and
flexibility/elasticity. In certain nonlimiting embodiments, a high
aspect pigment can be ground and added directly to the
polyurethane.
[0027] The barrier coating composition of the present invention may
optionally include other ingredients such as fillers, other than
the pigments described above, extenders, UV absorbers, light
stabilizers, plasticizers, surfactants and wetting agents. These
optional ingredients, if used, may comprise up to 10 weight
percent, with weight percent being based on the total solid weight
of the barrier coating composition.
[0028] In certain nonlimiting embodiments, the present barrier
coating compositions and/or polyurethane dispersions may be
water-based, such as in the form of an aqueous dispersion. The term
"water-based" as used herein refers to a composition in which the
carrier fluid of the composition is predominantly water on a weight
percent basis, i.e., more than 50 weight percent of the carrier
comprises water. The remainder of the carrier comprises less than
50 weight percent organic solvent, such as less than 25 weight
percent or less than 15 weight percent. Based on the total weight
of the barrier coating composition (including the carrier and
solids), the water may comprise up to about 90 weight percent. In
certain nonlimiting embodiments, the barrier coating composition
may be substantially solvent-free. The term "substantially
solvent-free" as used herein means that the barrier coating
composition contains less than about 15 or 20 weight percent
organic solvents, such as less than 5 or 10 weight percent, with
weight percent being based on the total weight of the coating
composition. For example, the coating composition may contain from
0 to 2 or 3 weight percent organic solvents.
[0029] In other nonlimiting embodiments of the present invention,
the barrier coating and/or polyurethane dispersions are
solvent-based. The term "solvent-based" as used herein refers to a
composition in which the carrier fluid is predominantly organic
solvent on a weight percent basis, i.e., more than 50 weight
percent of the carrier comprises organic solvent. Any compatible
suitable organic solvent(s) can be used.
[0030] The barrier coating compositions may form physical
crosslinks by drying, that is the coating composition may be a
thermoplastic that is cured at ambient or elevated temperature.
Alternatively, the coating compositions may comprise crosslinkers
that render the coatings thermosetting. Suitable crosslinkers
include carbodiimides, aminoplasts, aziridines, zinc/zirconium
ammonium carbonates and isocyanates. Water-based carbodiimides and
isocyanates may be particularly suitable in some applications
because they do not add a significant amount of organic solvent to
the barrier coating composition. Aziridines might be particularly
suitable in other applications. When a crosslinker is used, it is
typically present in an amount of up to about 50 weight percent,
based on the total solid weight of the barrier coating. In certain
nonlimiting embodiments, use of a crosslinker can result in better
barrier. It will be appreciated that when a crosslinker is used,
the coating in the present invention will be thermoset, and when a
crosslinker is not used, the coating of the present invention will
be a thermoplast.
[0031] The present invention is further directed to a method for
improving barrier on a substrate comprising applying to the
substrate any of the barrier coating compositions described above.
Any suitable substrate can be treated according to the present
invention. Typically, the substrates will be those that have gas
permeability, such as polymers, including but not limited to,
polyesters, polyolefins, polyamides, cellulosics, polystyrenes,
polyacrylics and polycarbonates. Poly(ethylene terephthalate),
poly(ethylene naphthalate), and combinations thereof may be
particularly suitable. Other typical substrates will be those that
exhibit flexibility and/or elasticity. "Flexible substrate",
"flexibility", and like terms refer to a substrate that can undergo
mechanical stresses, such as bending, stretching and the like,
without significant irreversible change. "Elastic substrate",
"elasticity", and like terms refer to a substrate that will become
distorted when it undergoes mechanical stresses, such as bending,
stretching and the like, and will substantially return to its
original shape when the mechanical stress is removed. Thus, it will
be appreciated that a flexible substrate may or may not also be an
elastic substrate. Examples of flexible substrates include nonrigid
substrates, such as thermoplastic urethane, synthetic leather,
natural leather, finished natural leather, finished synthetic
leather, ethylene vinyl acetate foam, polyolefins and polyolefin
blends, polyvinyl acetate and copolymers, polyvinyl chloride and
copolymers, urethane elastomers, synthetic textiles and natural
textiles. Elastic substrates include, for example, natural or
synthetic rubber.
[0032] Any of the barrier coating compositions described above can
be applied to a substrate according to any method known in the art.
For example, the coating can be applied by spraying, dipping,
brushing, rolling and the like.
[0033] Following application, the coating can be cured by any
suitable means.
[0034] Once cured, the coating on the substrate will typically have
a dry film thickness of 0.1 to 20 mils, such as 0.5 to 10 or 1 to
2.
[0035] The coatings and methods of the present invention can be
used for numerous end-use applications. Examples include but are
not limited to athletic balls, such as soccer balls, basketballs,
volleyballs, footballs, racquet balls, squash balls, beach balls,
tennis balls, golf balls, baseballs, and the like; inflatable
rafts; furniture, toys and the like; air mattresses; air bags; air
shocks; bladders; emergency slides; life vests; medical equipment
and devices, such as blood pressure bags, catheters, and the like;
tires, such as bike tires, automobile tires, bike tubes, ultra
terrain bike tires, motorcycle tires, lawn tractor tires and the
like; balloons; air bladders or other footwear applications;
packaging material, such as bottles, wraps, food or plastic sheets;
hoses; garbage bags; plastic light bulbs; fire extinguishers; LED
displays; plasma TV's; parachutes; scuba tanks; gas cylinders;
flexible foam; rigid foam, other pipes, hoses, tubes and the like;
architectural needs, such as windows, roofing, siding and the like;
fiber optic cables; seals and gaskets; batteries; clothing and
other textiles; swimming pool liners and covers; hot tubs; tanks;
electronics; buckets and pails.
[0036] As used herein, unless otherwise expressly specified, all
numbers such as those expressing values, ranges, amounts or
percentages may be read as if prefaced by the word "about", even if
the term does not expressly appear. Any numerical range recited
herein is intended to include all sub-ranges subsumed therein.
Plural encompasses singular and vice versa. Thus, while the
invention has been described in terms of "a" polyurethane, one or
more polyurethanes can be used. Similarly, one or more of any of
the other additives described herein or standard in the art can be
used. Also, as used herein, the term "polymer" is meant to refer to
prepolymers, oligomers and both homopolymers and copolymers; the
prefix "poly" refers to two or more.
EXAMPLES
[0037] The following examples are intended to illustrate the
invention, and should not be construed as limiting the invention in
any way.
Example 1
[0038] Hydroxyl-functional polyesters were prepared using the
following procedure. The ingredients listed in Table 1a were
charged to a round-bottomed glass flask equipped with a mechanical
stirrer, nitrogen inlet tube, thermometer, steam jacket column,
fractionating column, and a distillation head connected to a
condenser and a receiver. The resultant mixture was heated to react
in a nitrogen atmosphere. At about 160.degree. C., water generated
by the esterification process began to be collected. With
continuous removal of water, heating continued to 210.degree. C.
The reaction was allowed to continue until the acid value was below
3.0 mg KOH/gram, at which time the reaction product was cooled and
collected. Table 1a lists the polyester prepared by the foregoing
procedure (Polyester Sample No. 1), as well as several other
polyesters prepared by a similar procedure. The determined acid
value in mg KOH/gram, and hydroxyl value in mg KOH/gram for each
sample was determined and is shown in Table 1b, as are the Mw, Mn
and Mw/Mn values as determined by GPC (using linear polystyrene
standards).
1TABLE 1a Polyester Synthesis Hydroxyethyl Polyester Ethylene
Diethylene ether of Succinic Dibutyl Sample glycol glycol
resorcinol anhydride Isophthalic Adipic tin oxide No. (Eg) (g)
(DEG) (g) (HER) (g) (g) acid (g) acid (g) (DBTO) 1 -- 4176 -- 3500
-- -- 15.0 2 794.4 -- -- -- 1594.8 -- 4.7 3 -- -- 2137.5 -- --
1360.2 6.9 4 627.9 -- -- -- -- 1374.8 4.0 5 -- 986 -- -- -- 1015
4.0 6 693.8 -- -- -- -- 1305.5 4.0
[0039]
2TABLE 1b Polyester Analysis Polyester Sample No. M.sub.n M.sub.w
M.sub.w/M.sub.n Hydroxyl Value 1 2051 4108 2.0 65.3 1 1809 4381 2.4
62.2 2 822 1573 1.9 139.7 3 1344 2208 1.6 70.3 4 2458 6544 2.7 41.2
5 938 2296 2.4 145.5 6 1072 2203 2.1 142.9
Example 2
[0040] Polyurethane prepolymers were prepared in a similar manner.
The diols were combined (including HER and DMPA) and heated until
dissolved. This mixture was then added to isocyanate in an
appropriate solvent and held until a specific NCO equivalent weight
was reached. Specifically, a polyurethane prepolymer in the form of
an isocyanate-functional polymer was prepared in the following
manner. Polyester diol Sample No. 1 from Example 1 and Table 1a,
162.9 g, DMPA (2,2-bis(hydroxymethyl)propionic acid), 56.4 g and
HER (hydroxyethyl ether of resorcinol), 233.7 g, were charged to a
round-bottomed glass flask equipped with a mechanical stirrer,
nitrogen inlet, condenser and thermometer. The contents of the
flask were slowly heated to 110.degree. C. to dissolve the solids.
To a separate round-bottomed glass flask equipped with a mechanical
stirrer, nitrogen inlet, condenser and thermometer was added MEK,
420 g, and TDI (toluene diisocyanate), 327 g. The contents of this
flask were heated to 60.degree. C. with constant stirring. The
heated mixture of diols was then added slowly to the isocyanate
solution to form the polyurethane prepolymer. The diols were added
at a rate such that the temperature of the reaction did not exceed
80.degree. C. The reaction was held at 80.degree. C. until the NCO
equivalent weight was greater than 3000. The resultant polymer had
a non-volatile content of 62.2%, the acid value was 17.5 mg
KOH/gram and the NCO equivalent weight was 3380. GPC analysis gave
Mw=14229, Mn=4478 with Mw/Mn=3.2.
Example 3
[0041] The isocyanate-functional prepolymer of Example 2 was chain
extended and dispersed in water in the following manner. To a
round-bottomed glass flask equipped with a mechanical stirrer,
nitrogen inlet, condenser and thermometer was added deionized
water, 1533 g, MXDA (m-xylylenediamine), 23.0 g, and DMEA
(dimethylethanol amine), 33.4 g. The contents of the flask were
heating with stirring to 50.degree. C. The polyurethane prepolymer
of Example 2 was then dropped into the aqueous mixture over about
15 minutes followed by an MEK rinse, 60 g, resulting in a
milky-white dispersion. The dispersion was then put under vacuum to
remove MEK to a level of less than 0.1% by weight. The resultant
dispersion had a non-volatile content of 35.8%, the pH was 8.9, meq
acid was 0.195 and meq base was 0.197. GPC analysis (dmf) yielded
Mw=40360, Mn=10802 with Mw/Mn=3.7.
[0042] Table 2 lists the ingredients of the polyurethane dispersion
prepared in the foregoing example (Dispersion Code No. 1), as well
as ingredients of several other polyurethane dispersions prepared
in a similar manner using polyester diols. The values listed in
Table 2 represent grams of each listed ingredient.
3TABLE 2 Polyurethane Dispersions (Polyester) Polyester Sample No.
(from Table 1a) 1 3 6 5 4 DEG/ 2 HER/ EG/ DEG/ EG/ Dispersion
succinic EG/ adipic adipic adipic adipic Code No. anhydride
isophthalic acid acid acid acid DMPA HER TDI m-pyrol 1 162.9 -- --
-- -- -- 56.4 233.7 327.0 -- 2 68.5 -- -- -- -- -- 48.0 230.8 302.7
57.9 3 107.3 -- -- -- -- -- 46.0 194.9 301.8 -- 4 123.3 -- -- -- --
-- 46.3 194.9 285.5 -- 5 162.9 -- -- -- -- -- 56.4 233.7 327.0 72.8
6 256.8 -- -- -- -- -- 86.9 373.5 527.5 -- 7 -- -- -- 139.8 -- --
46.2 196.5 267.4 -- 8 -- -- -- -- 123.2 -- 46.2 195.4 285.4 -- 9 --
-- -- -- -- 123.6 46.0 195.6 284.8 -- 10 -- 142.7 -- -- -- -- 46.1
175.6 285.4 48.3 11 268.3 -- -- -- -- -- 90.8 390.0 551.0 -- 12
33.9 -- -- -- -- -- 11.8 48.7 68.1 -- 13 33.9 -- -- -- -- -- 11.8
48.7 68.1 15.2 14 62.5 -- -- -- -- -- 37.0 181.8 238.6 -- 15 118.0
-- 106.2 -- -- -- 46.0 141.6 238.3 65.0 16 47.8 -- -- -- -- -- 11.7
40.6 62.4 16.5 17 730.3 -- -- -- -- -- 57.3 -- 188.1 81.2 18 62.5
-- -- -- -- -- 37.0 181.8 238.6 -- 19 161.3 -- -- -- -- -- 46.9
162.3 279.5 59.0 20 162.9 -- -- -- -- -- 56.4 233.7 327.0 72.8 21
286.7 -- -- -- -- -- 70.1 243.8 374.4 98.8 22 162.9 -- -- -- -- --
56.4 233.7 327.0 72.8 23 191.2 -- -- -- -- -- 46.7 162.5 249.6 65.8
24 191.2 -- -- -- -- -- 46.7 162.5 249.6 65.8 25 376.4 -- -- -- --
-- 67.2 193.9 337.5 102.1 26 268.3 -- -- -- -- -- 90.8 390.0 551.0
-- 27 240.4 -- -- -- -- -- 81.3 349.6 493.9 -- 28 174.6 -- -- -- --
-- 40.9 182.1 252.4 -- 29 274.6 -- -- -- -- -- 68.7 192.2 439.4* --
Dispersion DI MICROLITE MICROLITE Code No. MEK Water MXDA DMEA 923
963 HEEU MEK 1 420.0 1533.2 23.0 33.4 -- -- -- 60.0 2 292.1 1306.4
20.3 24.9 -- -- -- 50.0 3 350.0 1742.8 39.9 29.3 -- -- -- 0.0 4
350.0 1693.0 25.0 27.7 -- -- -- 0.0 5 347.1 1629.0 12.7 34.1 -- --
-- 60.0 6 670.3 2181.0 41.3 52.5 -- 1714.3 -- 95.7 7 350.0 1720.1
15.4 28.6 -- -- -- 50 8 349.8 1710.7 17.6 28.4 -- -- -- 50 9 350.0
1680.8 12.3 24.9 -- -- -- 50 10 301.9 1766 24.2 26.5 -- -- -- 50 11
700.0 1300.0 39.9 50.6 -- 1746.6 -- 100.0 12 87.5 160.0 4.8 6.3
206.0 -- -- 12.5 13 72.3 219.3 2.7 7.1 217.3 -- 11.6 12.5 14 280.0
864.4 14.7 21.6 -- 692.0 -- 40.0 15 285.0 1665.3 20.9 25.6 -- -- --
50 16 71.0 219.3 3.4 7.2 217.3 -- 11.9 12.5 17 444.1 2647.1 15.2
39.7 -- -- -- 75.0 18 280.0 1402.1 14.7 21.6 -- -- -- 40.0 19 291.1
1628.4 40.4 27.8 -- -- 50.3 50.0 20 347.1 1728.0 12.7 34.1 -- --
55.6 60.0 21 426.2 2647.1 17.1 42.6 -- -- 69.6 75.0 22 347.1 1734.8
15.1 34.1 -- -- 55.8 60.0 23 284.2 1541.4 13.6 28.9 -- -- -- 50.0
24 284.2 1494.0 13.6 28.9 -- -- 47.4 50.0 25 422.9 2173.1 17.3 33.1
-- -- 69.6 75.0 26 700.0 1938.4 40.0 50.7 -- 1746.6 -- 100.0 27
749.8 2681.0 41.3 52.5 -- 1714 -- 95.0 28 350.0 1604.8 12.7 27.0 --
-- -- 50.0 29 525.1 2711.0 16.1 40.3 -- -- -- 50.0 *TMXDI was used
in place of TDI. MICROLITE 923 and 963 are supplied at 7.5% solids
in water. MICROLITE is a dispersion of vermiculite sold by W. R.
Grace. HEEU--hydroxyethyl ethylene urea MEK--methyl ethyl
ketone.
Example 4
[0043] Table 3 lists additional polyurethane dispersions prepared
without polyester. These polyurethane prepolymers and dispersions
were prepared in substantially the same way as described in
Examples 2 and 3.
4TABLE 3 Polyurethane Dispersions (Non-Polyester) Dispersion
JEFFAMINE m- DI Code No. DMPA TEG DEG EG XTJ-500 HER TDI pyrol MEK
Water 30 45.4 63.4 -- -- -- 213.4 327.6 46.5 303.5 1212.9 31 30.2
-- 14.7 8.8 -- 140.6 228.2 32.4 195.1 1030.8 32 30.2 -- 14.7 8.8 --
140.6 228.2 32.4 195.1 992.2 33 47.2 -- -- -- 67.4 226.8 308.7 49.4
300.6 1220.4 Dispersion MICROLITE MICROLITE Code No. MXDA DMEA 923
963 HEEU MEK 30 14.7 24.9 -- -- -- 0 31 12.2 15.3 -- -- -- 32.5 32
0 16.8 -- -- -- 32.5 33 17.5 24.9 -- -- -- 0 TEG--tetraethylene
glycol. JEFFAMINE XTJ-500 is a polyether diamine commercially
available from Huntsman.
Example 5
[0044] Several coating materials having compositions as listed
below in Table 4 were spray-applied to Mylar sheets, and subjected
to oxygen barrier testing. The results are listed in Table 4. All
of the oxygen permeabilities were measured using an OXTRAN 2/20 at
36 percent R.H., unless otherwise indicated.
5TABLE 4 Coated Mylar Oxygen Barrier Properties Filler Coating
Dispersion Composition Coating PO.sub.2 of the Code No. Code No.
and Amount Thickness coating M1 2 0.1/1 p/b 0.25 mil 0.01 Microlite
963 M2 2 0.1/1 p/b 0.52 mil 0.02 Microlite 963 M3 30 0.1/1 p/b 0.44
mil 0.02 Microlite 963 M4 1 0.1/1 p/b 0.32 mil 0.02 Microlite 963
M5 3 0.1/1 p/b 0.33 mil 0.02 Microlite 963 M6 4 0.1/1 p/b 0.31 mil
0.02 Microlite 963 M7 2 0.1/1 p/b 0.48 mil 0.03 Microlite 923 M8 2
0.06/1 p/b 0.35 mil 0.03 Microlite 923 M9 5 0.1/1 p/b 0.61 mil 0.03
Microlite 963 M10 5 0.1/1 p/b 0.61 mil 0.03 Microlite 963++ M11 2
0.1/1 p/b 0.47 mil 0.03 Microlite 963 M12 31 0.1/1 p/b 0.57 mil
0.03 Microlite 963 M13 32 0.1/1 p/b 0.56 mil 0.03 Microlite 963 M14
1 0.1/1 p/b 0.67 mil 0.03 Microlite 963 M15 6 0.1/1 p/b 0.56 mil
0.03 Microlite 963 M16 7 0.1/1 p/b 0.37 mil 0.03 Microlite 963 M17
8 0.1/1 p/b 0.55 mil 0.03 Microlite 963 M18 9 0.1/1 p/b 0.35 mil
0.03 Microlite 963 M19 2 0.1/1 p/b 0.48 mil 0.04 Microlite 923 M20
33 0.1/1 p/b 0.44 mil 0.04 Microlite 963 M21 10 0.1/1 p/b 0.39 mil
0.04 Microlite 963 M22 10 0.1/1 p/b 0.41 mil 0.04 Microlite 963 M23
11 0.58 mil 0.05 M24 11 0.1/1 p/b 0.47 mil 0.048 Microlite 963 M25
2 0.08/1 p/b 0.38 mil 0.05 Microlite 923 M26 5 0.08/1 p/b 0.17 mil
0.05 Microlite 923 M27 11 0.1/1 p/b 0.50 mil 0.053 Microlite 963
M28 2 0.06/1 p/b 0.42 mil 0.06 Microlite 963 M29 5 0.12/1 p/b 0.30
mil 0.06 Microlite 923 M30 12 0.1/1 p/b 0.91 mil 0.07 Microlite 923
M31* 2 0.1/1 p/b 0.25 mil 0.08 Microlite 963 M32 12 0.1/1 p/b 1.17
mil 0.1 Microlite 923 M33 14 0.60 mil 0.12 M34 5 0.05/1 p/b 0.60
mil 0.12 Microlite 963 M35** 1 0.1/1 p/b 0.67 mil 0.13 Microlite
963 M36 15 0.1/1 p/b 0.65 mil 0.14 Microlite 963 M37 14 0.60 mil
0.22 M38 2 0.1/1 p/b mica 0.49 mil 0.33 M39 16 0.1/1 p/b 0.58
Microlite 923 M40 1 0.45 mil 0.6 M41 5 0.01/1 p/b 0.49 mil 0.67
Microlite 963 M42 5 (1/3) 0.49 mil 0.67 32 (2/3) M43 5 0.1/1 p/b
0.71 mil 0.68 Microlite 963++ M44 2 0.42 mil 0.69 M45 5 0.1/1 p/b
mica 0.32 mil 0.7 M46 5 0.08/1 p/b mica 0.20 mil 0.74 M47 5 0.06/1
p/b mica 0.28 mil 0.79 M48 5 (1/3) 0.54 mil 0.81 30 (2/3) M49 5
(1/3) 0.63 mil 0.84 31 (2/3) M50 5 0.1/1 p/b Cloisite 0.73 mil 0.85
NA+ clay M51 17 0.1/1 p/b 0.36 mil 0.9 Microlite 923 M52 7 0.34 mil
0.91 M53 5 0.1/1 p/b 0.46 mil 0.98 Nanocor M54 33 0.86 mil 1.09
M55** 1 0.45 mil 1.36 M56 5 0.68 mil 1.51 M57 5 0.50 mil 1.65 M58
18 (2/10) 0.40 mil 1.65 14 (8/10) M59 20 0.30 mil 2.29 M60 15 0.86
mil 2.8 M61 22 0.40 mil 2.97 M62 18 (4/10) 0.50 mil 5.29 14 (6/10)
M63 8 n.g. M64 32 n.g. M65 30 n.g. M66 31 n.g. M67 10 n.g. M68 10
n.g. M69 18 n.g. M70 9 n.g. *72-76% R.H. **76% R.H.
[0045] As shown in Table 4, the gas barrier coatings possess
excellent oxygen barrier properties.
Example 6
[0046] Two coating materials having compositions as listed below in
Table 6 were spray-applied to 0.6 mil thick polypropylene sheets,
and subjected to permeance testing similar to Example 6 with Mocon
Company's OXTRAN 2/20 at 23.degree. C. and 50% R.H. (N.sub.2 and
O.sub.2) for Coating P1 and at 78% R.H. (N.sub.2) and 85% R.H.
(O.sub.2) for Coating P2. The results are listed in Table 6.
6TABLE 5 Coated Polypropylene Oxygen Barrier Properties Coating
Filler Code Dispersion Composition Coating Permeance No. Code No.
and Amount Thickness cc/m/day P1 26 Microlite 963 0.89 mil 0.66
0.1/1 p/b P2 26 Microlite 963 0.89 mil 14.7 0.1/1 p/b
Example 7
[0047] A polyester prepolymer was prepared in a four-neck round
bottom flask equipped with an electronic temperature probe,
mechanical stirrer, condenser, dry nitrogen sparge, and a heating
mantle. The following ingredients were used:
7 diethylene glycol 3500.0 g succinic anhydride 4176.0 g dibutyltin
oxide 15.0 g
[0048] The ingredients were charged to the flask and the
temperature was gradually increased to 210.degree. C. over a
four-hour period while stirring, sparging with nitrogen, and
collecting the distillate. The reaction temperature was then held
at 210.degree. C. for 20 hours until the acid value dropped to 10.6
and 561 ml of distillate was collected. The final product was a
dark orange liquid with a Gardner-Holdt viscosity of Z6+, an acid
value of 10.6, a number average molecular weight (MN) of 1734, a
weight average molecular weight (M.sub.w) of 3394, and a
nonvolatile content of 98.5% (measured at 110.degree. C. for one
hour).
Example 8
[0049] A polyurethane dispersion with TDI and 20 percent HER was
prepared in a four-neck round bottom flask equipped with an
electronic temperature probe, mechanical stirrer, condenser,
nitrogen atmosphere, and a heating mantle. The following
ingredients were used:
8 Charge A toluene diisocyanate (TDI) 470.0 g methyl ethyl ketone
548.0 g Charge B N-methyl pyrrolidinone 84.0 g dimethylolpropionic
acid (DMPA) 93.6 g polyester pre-polymer of Example 1 582.4 g
1,3-bis(2-hydroxyethoxy) benzene (or 270.0 g hydroxyethyl
resorcinol, HER) Charge C methyl ethyl ketone 40.0 g Charge D
methyl ethyl ketone 105.0 g Charge E water 2173.1 g
dimethylethanolamine 33.1 g hydroxyethyl ethyleneurea (HEEU) 69.6 g
meta-xylene diamine (MXDA 17.3 g Charge F methyl ethyl ketone 75.0
g
[0050] Charge A was stirred in the flask at a temperature of
75.degree. C. Charge B was heated in a separate flask to a
temperature of 90.degree. C. and added to Charge A over a one hour
period at a temperature of 80.degree. C. Charge C was used to rinse
the Charge B flask and then added to the reaction mixture. The
reaction mixture was held at 80.degree. C. for an additional three
hours at which time Charge D was added. Charge E was heated to
50.degree. C. in a separate 12 liter four-neck round-bottom flask
under a nitrogen atmosphere. 1500.0 g of the reaction product of
Charges A, B, C, and D was added to Charge E over a ten-minute
period followed by the addition of Charge F. The methyl ethyl
ketone was removed by vacuum distillation at 50.degree. C. The
final dispersion had a Brookfield viscosity of 512 centipoise
(spindle #2, 60 rpm), an acid value of 12.2, a pH of 7.1, and a
nonvolatile content of 37.6% (measured at 110.degree. C. for one
hour).
Example 9
[0051] A polyurethane dispersion with TDI and no HER was prepared
in a four-neck round bottom flask equipped with an electronic
temperature probe, mechanical stirrer, condenser, nitrogen
atmosphere, and a heating mantle. The following ingredients were
used:
9 Charge A toluene diisocyanate (TDI) 193.0 g methyl ethyl ketone
377.0 g Charge B N-methyl pyrrolidinone 22.0 g dimethylolpropionic
acid (DMPA) 64.0 g polyester pre-polymer of Example 7 782.0 g
Charge C methyl ethyl ketone 40.0 g Charge D water 1714.0 g
dimethylethanolamine 26.2 g hydroxyethyl ethyleneurea (HEEU) 54.9 g
meta-xylene diamine (MXDA) 10.0 g Charge E methyl ethyl ketone 59.4
g
[0052] Charge A was stirred in the flask at a temperature of
70.degree. C. Charge B was heated in a separate flask to a
temperature of 90.degree. C. and added to charge A over a thirty
minute period at a temperature of 80.degree. C. Charge C was used
to rinse the Charge B flask and then added to the reaction mixture.
The reaction mixture was held at 80.degree. C. for an additional
five hours. Charge D was heated to 50.degree. C. in a separate 12
liter four-neck round-bottom flask under a nitrogen atmosphere.
1188.0 g of the reaction product of Charges A, B, and C was added
to Charge D over a ten-minute period followed by the addition of
Charge E. The methyl ethyl ketone was removed by vacuum
distillation at 50.degree. C. The final dispersion had a Brookfield
viscosity of 731 centipoise (spindle #3, 60 rpm), an acid value of
12.1, a pH of 6.6, and a nonvolatile content of 41.7% (measured at
110.degree. C. for one hour).
Example 10
[0053] A coating according to the present invention was prepared as
follows:
10 Name Weight Polyurethane dispersion of Example 8 25.32
Polyurethane dispersion of Example 9 22.45 Both under agitation,
stir together DARAN SL-143.sup.1 51.49 Neutralize to pH 6-6.5 with
ammonia under agitation Add slowly to polyurethane dispersion
mixture, stir 10 minutes LW-44.sup.2 0.58 Add under agitation, stir
5 minutes XHD-47J.sup.3 0.16 Add under agitation, stir 5 minutes
TOTAL 100.0 .sup.1PVDC terpolymer from Hampshire Corporation,
Ammonia (KAR-5995). .sup.2Associative thickener from Bayer
Corporation. .sup.3Defoamer from Ultra Additives.
[0054] The elongation and P(O.sub.2) of the coating were as
follows:
11 Elongation @ 25.degree. C..sup.4 P(O.sub.2).sup.5 400% 2.26
.sup.4Obtained from Instron measurement, in which a rectangular
sample (1/2 inch wide, 3 inches long) is stretched. .sup.5Measured
by Mocon equipment using Oxygen as test gas; unit is cc-mil/100
in.sup.2-day-atm at 0% relative humidity.
[0055] Whereas particular embodiments of this invention have been
described above for purposes of illustration, it will be evident to
those skilled in the art that numerous variations of the details of
the present invention may be made without departing from the
invention as defined in the appended claims.
* * * * *