Note: Descriptions are shown in the official language in which they were submitted.
1037~7~
This invention relates to aqueous dispersion~ of
ethylene copolymers, wax and a terpolymer of vinyl acetate,
ethylene and N-methylol acrylamide which produce water-
repellent coatings.
Wax containing compositions as water-repellent
coatings are well known, as indicated by such sources as
"Waterproofing Textiles - 1970", M. W. Ranney, Editor,
Noyes Data Corporation~ Park Ridge, New Jersey. Such
coatings tend to have certain disadvantageous character-
istics: (l) a slippery feel or hand, making the finish
.
feel almost wet, (2) crocking (tendency of the coating to
rub off) is generally poor, (3) coating weights are
usually relatively hea~y; the coating weight is usually
; about one-half or more of the fabric weight, and (4) when
coatings are applied from a hydrocarbon solvent~ there
are problems due to toxicity to workers, atmospheric
pollution, and flammability.
; ~ore recen~y aque~us coa~ s base~ on
ethy~ene copolymers/wax dispersions have ~een deYel~ped.
Such coatings offer beneficial properties: (l) dry hand,
(2) improved dry crock resistance~ (3) lower coatin~
weights~ o~e-fourth to one-third of the fabric weight,
(~) hydrocarbon solvents are eliminated.
There are basically two~types of textile water-
repellent coatir~s: (I) those having poor to medium wash
fastness (wax, resin, pyridinium or silicone based), and
(II) those having excellent wash fas1;ness (fluorocarbon
,
based). Although type (I) water-repellent coatings do not
have the wash fastness of the type (II) coatings, type
(I) coatings are often preferred. For example, type (I)
-2-
~ 037177
coatings are usually more economical.
Aqueous dispersions from which type (I~ water-
repellent coatings can be applied are described in U. S.
Patent No. 3,347,~11, issued to T. C. Bissot on October
17, 1967~ and U. S. Patent No. 3,296,172, issued to D. L.
Funck and V. C. Wolff, Jr., on January 3, 1967. Although
these coatings are useful and have good water-repellent
characteristics, a type (I) water repellent having complete-
ly satisfactory water-repelIent characteristics, such as
initial water repellency has not yet been provided.
I U- S- Patent 3,741,925 discloses such an aqueous
; dispersion having an ethylene copolymer comprising at
leaæt 30 percent by ~eight ethylene and up to 70 percent
; by weight of at lea~t one comonomer having polar
characteristics~ a wax, an ammonium salt of a mineral
acid~ and from O to 25 percent by weight of an amino-
~ormaldehyde resin~ such as hexamethoxymethylmelamine.
Although that system represents an improvement over the
,~ ~ prior art, it too has at least ~one disadvantage in~ 20 commercial operation; the compositions tend to thicken
on standing. The thickening process can cause difficulty
in applying coatings with a pattern box~ or it may pro-
~¦~ ceed to the point where the coating is completely
coagulated.
U. S. Patent 3~756,973 discloses storage-stable
aqueous dispersions having an ethylene copolymer comprising
at least 30 percent by weight ethylene and up to 7~ percent
by weight of an alpha, beta-ethylenically unsaturated
carboxylic acid having up to 75 percent of its acid
groups neutralized with alkali metal ions, wax, and
-3-
l ~`
water-soluble, low molecular weig~t methylated melamine-
formaldehyde resin. Use of the low molecular weight
methylated melamine-formaldehyde resin permits an
increased curing rate. The resin also permits curing
without catalysts, ammonium salts of mineral acids,
which cause thickening of the dispersion. ~ile the
dispersion is YiSCosity stable, fabrics having sufficient
add-on or coating weight for good water repellency tend
to be boardy, i.e., have a stiff hand.
i 10 Coatings~made from vinyl acetate/ethylene/
N-methylol acrylamide terpolymer emulsion such as
described in U. S. Patent 3,345,31~ do not have
satisfactory water repellency.
According to the present invention there is
provided an aqueous dispersion comprisin~ a mixture of
(1) an ethylene copolymer comprising at least 30 percent
by weight ethylene and up to 70 percent by weight Or an
alpha, beta-ethylenically unsaturated carboxylic acid and
a wax, and (2) an emulsion o~ a terpolymer of vinyl
acetate, ethylene and N-methylol acrylamide. The
dispersions give excellent water repellent properties to
a variety Or fabrics. The dispersions can be applied
to the fabrics by ordinary methods~ dried and cured by
heating. In addition, the coated fabrics have the
a~vanta~es Or soft hand, excellent viscosity stability
of formulated mixtures, acceptance of mildewcides or
fungicides ~nthout adversely affecting viscosity
stability, and good crock fastness.
The essential in~redients of the present
3o dispersion comprise, in aqueous medium, an ethylene/
-4-
1 {'` 1037~7
alpha, beta-ethylenically unsaturated carboxylic acid
- copolymer (preferably an ionomer), a wax, and a terpolymer
of ~inyl acetate/ethylene/N-methylol acrylamide.
The ethylene copolymers useful in this invention
have an ethylene content of at least 30 percent by weight,
? preferably 30 to 95 percent by weight, and up to 70 per-
- cent by weight, preferably 5 to 70 percent by weight, of
an alpha, beta-ethylenically unsaturated carboxylic acid.
Examples of suitable alpha, beta-ethylenically unsaturated
carboxylic acids are acrylic aoid, methacrylic acid,
itaconic acid, maleic acid, fumaric acid, and aconitic
acid. Preferably the acid moiety of the copolymer will
be partially neutralized, e.g., up to about 75 percent
.
of the acid groups neutralized, with alkali metal ions.
Such partially neutralized copolymers are commonly
referred to as ionomers.
A`particularly preferred copolymer is a copolymer
- - of ethylene and methacrylic acid having at least 70 per-
cent by weight of ethylene and up to 30 percent by weight
of methacrylic acid. Such copolymers are generally
prepared by high-pressure, free-radical cataIytic process-
es, but they can also be prepared by low-pressure
coordination catalytic processes. The molecular weight
can be varied over a wide range; however, copolymers
having molecular weights corresponding to melt indexes of
5 to 1,000, preferably 150 or less, are especially suited
` for use in this invention. Copolymer melt index is
determined as described in .~STM D-123~-65T.
The waxes suitable for the practice of this
invention can be o~ natural, mineral, petroleum, or
f~ -5-
~1 .
~ 103717~7
synthetic origin. Natural waxes include beeswax, woolwax,
Japan wax, myrtle, mace, palm kernel, spermaceti, carnauba,
; candellia, and bayberry; mineral waxes include materials
such as Montan wax and paraffin waxes from shale oils or
coal; petroleum waxes include both the paraffin and
microcrystalline types; and synthetic waxes include
haLogenated hydrocarbons, e.g., chlorinated paraffins, t
polyethylene wax, alpha-olefin waxes, and Fischer-
Tropsch waxes.
I 10 Preferred waxes are the paraffin waxes of
- p~troleum origin. mese materials are normally very
difricult to convert into stable aqueous dispersions
without downgrading many of their inherent desirable
properties. These waxes are mixtures of solid hydro-
carbons derived from the overhead wax distillate
fraction obtained from fractional~distillation of
p-troleum. After purification, the paraffin wax contains
hydrocarbons that fall within the formulas C23H4g to
` C35H7~. The waxes are hard, colorless, and translucent
materials having melting points generally in the range
from about 120~ to 200F. (49 to 93C.), preferably 120
to 1~0F. (49 to ~20C.j. An especially preferred
paraffin wax melts in the range of from 143 to 153F.
; ~62- to 670C.).
Preferred chlorinated paraffin waxes are the
chlorinated, saturated hydrocarbons of the C10 to C30
range having a chlorine content of ~0 to 70 percent, as
described by Hardie, ~Chlorinated Hydrocarbons", in
Volume 5, "Encyclopedia of Chemical Technology", page 231,
3 Kirk-Othmer, Second Edition, 1964. Depending upon their
-6-
1037~7~7
chlorine content, these chlorlnated para~fins have melting
polnts from -30C. (42 percent chlorine) to 90C. (70
percent chlorine).
me ethylene copolymer/wax dispersion can be
prepared by any mean~ known in the art. me ethylene
cop~lymer and wax can be separately dlspersed in aqueous
media and then mixed or, i~ the copolymer is an ionomer,
they can be codispersed according to the method dlsclosed
in French Pa~ent 70.06669 of E. I. du Pont de Nemour~ and
Company, granted November 16, 1970.
me weight ratio of wax to ethylene copolymer
i8 an important consideratlon because of two performance
properties involved; namely, water repellency and coating
adhesion (crock resistance). Water repellency, or the
ablllty of the coated fabric to shed water, is a function
of the wax content. Higher wax contents give better water
repellency. The ethylene/alpha, beta-ethylenically un-
saturated carboxglic acld component provide~ adhesion to
the fabric, more specificallg, the acid functionality of
the copolymer provides adhesion. merefore, lt i8
desirable to lncrease the ethylene/alpha, beta-ethylenically
unsaturated carboxglic acid copolymer content or, more
preferably, increase the alpha, beta-ethylenically un-
saturated carboxglic acid content, in the copolgmer/wax
combination. Obviously, both wax and alpha, beta-
ethylenically unsaturated carboxylic acid content cannot
be increased beyond certain limits. A workable range of
weight ratios oi wax to ethylene copolymer is about from
1:1 to 19:1, preferably from 1:1 to 6:1, and more
preferablg from 1.5:1 to 6:1.
The terpol~mer emulsion has a range of solids
103717~7 .
in weight percent of 64 to 77 vinyl acetate, 20 to 30
ethylene, and 3 to 6 N-methylol acrylamide. The terpolymer
is useful having the content of components within the
given range. It has been found that the hand softness
iq particularly related to the ethylene component. It is
not desirable to decrease the ethylene content below about
20 weight percent because of the increase Or modulus of t
the terpolymer. m e fabric coated therewith would have
a boardy or harsh hand. Increased amounts of vinyl
acetate tend to make the coated fabric stiff. N-methylol
acrylamide within th~ stated range provides good body,
tensile strength and crosslinkability.
While the particular method of preparing the
terpolymers is not limited, a particularly suitable method
18 a batch process which involves first poIymerizing a
portion (usually about lO~) of the vinyl acetate under
an ethylene pressure in an emulsion and, thereafter,
continuously adding the remaining vinyl acetate and
N-methylol acrylamide to the reaction vessel. The
polymerization is accomplished in the presence of a
catalyst and at least one emulsifying agent, portions of
which are added initially and with the continuous
addition. The aqueous system is preferably maintained, by
1 .
a suitable buffering agent, at a pH of 5 to 7 during the
, . .. .
polymerization. Polymerization temperatures and ethylene
pres~ures are preferably ~0-~0C. and 100-2000 psi. (6.~-
136.0~ atm.), respectively, the higher pressures being
' used when it is desired to introduce a relatively large
amount of ethylene into the interpolymer.
,. .
~3 _g_
~1
lQ371
3 An additional general method Or preparing the
present terpolymers is described ln Netherland~ Applica-
tion 6,604,289 of Cumberland Chemical Corporatlon, published
October 3, 1966, and French Patent 1,4.72,857 o~ Alr Products,
published March 10, 1967, as rollow~: .
Vlnyl acetate and ethylene are copolymerlzed in
the presence of the N-methylol acrylamide in an aqueous
medium under pressures not exceeding lOO atmospheres in c
the presence Or a catalyst and at least one emulslfylng
agent, the aqueous system belng malntained, by a suitable
bu~fering agent, at a pH of 2 to 6, the catalyst being
added incrementally. The process is a batch process
~hich inrolres ~ir~t a homogenization period in whlch the
vinyl acetate suspended in water is thoroughly agitated
in the presence of ethylene under the working pressure to
e~fect solution Or the ethylene in the vinyl acetate up to
the substantial limit o~ its solubility under the condi-
tions existing in the reactlon zone, whlle the vinyl
acetate is gradually heated to polymerlzation temperature
~30-80C., preferably 50C.). me
homogenization period
i8 followed by a polymerlzation p
eriod durlng which the
catalyst, which con~ists Or a mai
n catalyst or initiator,
and may include an activator, ls
added incrementally, and
t-he N-methylol.acrylamide is sim
ilarly added incrementallg,
the pressure ln the system belng
maintained substantlally
`. constant (10-100 atm.) by applica
tion of a constant
ethylene pressure.
Various free-radlcal fo
rmine catalysts can be
_g_
~.~,
1~37~
used in carrying out the polymerization to prepare the
present terpolymers. For example, combination type
catalysts employing both reducing agents and oxidizing
agents can be used. ~ The use of this type of combined
catalyst is generally referred to in the art as "redox
polymerization" or "redox system". The reducing agent is
also often referred to as an activator and the oxidizing
agent as an initiator. Suitable reducing agents or
.
activators include bisulfites, dithionites, sulfoxylates,
or other compounds havlng reducing properties such as
I ferrous salts, and tertiary amines; e.g., N-N-dimethyl
;~ àniline. The oxidizing agents or initiators include
;j hydrogen peroxide, organic peroxides, such as benzoyl
peroxide, t-butyl hydroperoxide and the like; persulfates,
such as ammonium or potassium persulfate; perborates, and
the like. Specific combination type catalysts or redox
systems which can be used include hydrogen peroxide,
;I ammonium persulfate, or potassium persulfate, with
sodium metabisulfite, sodium bisulfite, ferrous sulfate,
dimethyl aniline, zinc formaldehyde sulfoxylate, sodium
dithionite, or sodium formaldehyde sulfoxylate. In
~ general, redox catalyst systems are described, for example,
! in "Fundamental Principles of Polymerization" by G. F.
D'Alelio (John Wiley and Sons, Inc., New York, 19~2)
pages 333 et seq. Other types of catalysts are well
known in the art and can also be used to polymerize the
, monomers, with or without the addition of reducing agents
' or other activating materials.
I The catalyst is generally employed in an amount
of 0.1-2%, preferably 0. 5-1. 5%~ based on the weight of
.:
--10--
10~
vinyl acetate introduced into the system. With a redox
catalyst, the initiator is generally present in an amount
of 2-5 times that of the activator.
Nonionic or anionic emulsifying agents, as well
as mixtures, can be used in preparing the terpolymers.
Suitable nonionic emulsifying agents lnclude polyoxy-
ethylene condensates. Polyoxyethylene condensates can be
represented by the general formula:
R (CH2-CH2-O)nH
where R is the residue of a fatty alcohol containing 10-1
carbon atoms, an alkyl phenol, a fatty acid containing 10-
` 1~ carbon atoms, an amide, an amine, or a mercaptan, and
where n is an integer of 1 or above. Some specific
examples of polyoxyethylene condensates which can be used
include: polyoxyethylene aliphatic ethers, such as polyoxy-
ethylene lauryl ether, polyoxyethylene oleyl ether, poly-
oxyethylene hydroabietyl ether and the like; polyoxy-
ethylene alkaryl ethers, such as polyoxyethylene nonyl-
phenyl ether, polyoxyethylene octylphenyl ether and the
llke; polyoxyethylene esters of higher fatty acids, such
as polyoxyethylene laurate, polyoxyethylene oleate and the
like, as well as condensates of ethylene oxide with resin
; acids and tall oil acids; polyoxyethylene amide and amine
condensates, such as N-polyoxyethylene lauramide, and
N-lauryl-N-polyoxyethylene amine and the like; and
; polyoxyethylene thio-ethers, such as polyoxyethylene n-
dodecyl thlo-ether. Other nonionic emulsifiers! such
as the sugar esters of long-chain monocarboxylic acids
with ~-20 carbon atoms are useful as well.
Preferred emulsifying agents include monoalkyl
:
--11--
.
1~3q~7 7
phenoxy polyethylene oxide ester ~f phosphoric acid
(TRITON* QS-9 of Rohm & Haas), pre~erably 3.5% by weight
of polymer, and hydroxyethyl cellulose, preferably 0.3 to
0.5~ by welght of polymer.
Suitable anionlc emulslfiers can be characterized
by the following: salts of sulfosuccinic acld esters; ~alts
of higher alkyl sulronlc acldæ and alkyl aryl sulfonic
acids; and salt3 of long-chain alkyl monocarboxylic acids.
The concentration range of the total amount of emulsifying
agents useful is about 0.5 to 5~, based on the aqueous
phase of the dispersion regardle~s of the 601ids content.
me dry weight ratio of ethylene copolymer/wax
to terpolymer emulslon is from 70:30 to 20:80, preferably
50:50 to 30:70, all on a dry welght basi~.
e aqueous disperslon of this lnvention may
be applled to fabrlcs by slmply uslng the above essential
ingredients, for some applications it may be deslrable to
add one or more auxillary ingredient 8 to achieve certain
performance properties, to impart color, to use the
coating ln a specific manner, or to use a specific type
of equipment. Such auxiliary lngredients or addltives
include: flllers, pigmentæ, thickeners, mildewcides or
fungicides, defoamers, etc. a~ are descrlbed below.
While almost any of the flllers known in the
art can be used, the preferred filler types are kaolin
(aluminum silicate) and talc (magnesium silicate) and
whitlng (calcium carbonate). The preferred average
particle size of these fillers is 0.1 to 35
microns, more preferably from 0.1 to 30 microns, and
mo~t preferably from 0.3 to 25 microns.
* denotes trade mark
-12-
.~ .-
~ .J
,' ' . ' .
lonl7 7 -
The quantity of filler can vary over a wide
range. me filler to binder ratio ~binder being defined
as the total solids weight of ethylene copolymer, wax,
:. . -.
and terpolymer) may vary from about 0 to ~. The
preferred ratio is 0 to 2.
Filler is desirable when it is necessary to coat
an open wea~e or lightweight fabric because it gives bulk
to the coating, helping to fill the voids.
A large variety of pigments can be successfully
used in this invention. These materials are preferably
aqueous dispersions of organic or inorganic pigments and
should be anionic in nature. Nonionic dispersed pigments
may also be employed if desired, but are not preferred.
The amount of pigment can vary with the depth
of shading required~ and only the ultimate user can
- judge his requirements. Essentially any color coating
can be made. For a blue coating, the quantity of pigment
required to give a bright color shade is from about 0.025
to 0.030 ounce per square yard (0.0~ to 0.10 dyne/sq. cm.)
of coated fabric. Usually below 0.025 ounce per square yard
(0.0~ dyne/sq. cm.) the color depth is too lean, while at
greater than 0.03 ounce per square yard (0.10 dyne/sq. cm.),
pigmentation is too intense. To achieve the correct
pigmentation level, one must first find out what his
coating weights are with the coating system he is using
and then adjust the pigment level accordingly.
To improve brightness, it is desirable to add
titanium dioxide in addition to the colored pigment.
~ Usually one uses titanium dioxide to the extent of four 30 times the dry weight of colored pigment. Titanium dioxide
is best added as an a~ueous slurry of up to about 70
-13-
1037~7~7
percent solids. For white pigmented coatings, titanium
dioxide is used alone. Usually about lO percent of the
dry weight of the coating should be titanium dioxide to
give an acceptably bright coating. The peicentage of
titanium dioxide in the coating can be raised or lowered
from the 10 percent level according to the pigmentation
needs of the user. For non-white coatings, rutile titanlum
dioxide is preferred because of its improved hiding power
and better chalk resistance. For white coatings, a
mixture of rutile and anatase titanium dioxide is preferred.
The chalking of the anatase gives the white coating a
better and clearer appearance.
For certain coating application ~echniques it
is desirable to increase the viscosity of the aqueous
coating composition. This may be done by adding
materials commonly known as thickening agents, which are
I
viscosity modifiers. A number of these agents have
been found useful for the compositions used in this in-
vention. Examples of some materials that are useful are
copolymers of methyl vinyl ether and maleic anhydride,
polyethylene oxide polymers, hydroxyethyl cellulose,
and polyacrylic acid polymers that have been neutralized
with bases, such as ammonium hydroxide. The criteria
for a useful thickener are water solubility, compatibility
with the composition, and reasonable viscosity stability,
the limits for which must be set by the ultimate user.
Any thickener meeting these criteria may be employed.
The amount of thickener needed varies according
to the solids level in the coating composition and the
nature of the thickener. Usually, as the solids content
-14-
103717~7
of the coatlng increa~e3, the amount of thickener needed de-
creases. On the other hand, at low solids levels, the quantity
of thickener may be increased to get to a certain visco~ity.
me usual quantity of thickener required ls from O to 15
percent by weight of total sollds, preferably from O to 6
percent and more preferably from 0.1 to 5 percent by weight.
It ma~ be deslrable to incorporate a mildewcide into the
coating to prevent weakening of cellulo~ic fabrics by
organisms. One materlal effectlve for this use ls a
synergistic mixture of zinc salts of dlmethyldithiocarbamic
acid and 2-mercaptobenzothiazole (F~NGICIDE ZV* by
Arkansas Company). When the dry weight of this material
i8 2 percent by weight of the total solids, resi~tance
to organism attack of the cellulose i8 obtained. Lesser
quantities of this component reduce resistance. Sali-
cylanilide and copper 8-quinolinolate have also been
found to be u~eful mildewcide~.
Another ingredient which may be added is an
antifoaming or defoaming agent which prevents or breaks
air entrainment. A variety of these agent 8 i S known to
those skilled ln the art. One particularly effective
foam-control agent is marketed by Cruclble Chemical Co. J
; under the name of FOAMKILL* 649, a hydrocarbon-oil-based
material.
The pigmented coatings may be formulated with
; chlorowax (chlorinated paraffin wax) and antimony trioxide
to give a flame retardant coating. me ratio of antimony
- trioxlde to chlorowax i~ within the range of about 0.25:1
to 3:1, preferably 0.5:1 to 2:1. The chlorowax should
contain greater than about 50 percent by weight chlorine,
* denote~ trade mark
-15-
103717~
preferably between 60 and 70 percent, and the total
chlorine content in the coating should be within the range
of about 20 to 60 percent by weight.
The type of composition prepared depends upon
such considerations as method of application, coating weight
desired, and desirability of using a pigmented coating.
mere are two basic application techniques, padding and
blading. In a padding operation the ~abric is immersed
in a coating bath, at ambient temperature, and led
through a device for removing excess coating, a set of
wringer rolls, scraping bars, or some other means.
i Normally, but not always, the padding process utilizes a
composition having a viscosity from about 5 to 1500 cps.,-
preferably 50 to lO00 cps. In blade coating, a puddle of
coating is placed on top of a horizontally-held fabric,
and the blade is drawn through the coating over the
fabric surface to give a uniform layer of coating. For
this application, it is usually necessary to use a higher
coating viscosity, in the range of 1500 to ~000 cps.,
preferably 2000 to 4000 cps. A higher viscosity is
necessary to prevent the coating from soaking through to
the opposite side of the fabric.
Regardless of what application method is being
used, coating weights are best controlled by the solids
level in the coating. A useful range of ethylene copolymer/
wax and terpolymer coating solids is from 30 to 99 parts
by weight per lO0 parts by weight of total coating on a
dry basis. A preferred range is 35 to 70 parts by weight
per 100 parts of total coating on a dry basis. The coating
weight used depends upon the performance requirements.
-16-
10~
For simple repel}ency, 0.1 to 0.2 oz./yd.2 (3.34 to 6.6~
dynes/sq. cm.) of dry coating may be sufficient; but~ for a
high performance system, as much as 3.0 to 3.5 oz./yd.2
I tlO0.2 to 116.9 dynes/sq. cm.) may be desirable.
Compositlons are prepared according to the type
of coating system being employed. A nonpigmented type
of water-repellent coating can be prepared by mixing the
ethylene copolymer/wax dispersion with an emulsion of
the terpolymer and adjustlng the solids level to the desired
degree with water. The pH should be adjusted to about 10
I with aqueous ammonium hydroxide. ~lixtures must be agitated
1. .
to insure homogeneity. It does not appear to be necessary
that the terpolymer be completely dissolved in the aqueous
phase; however, it should at least be uniformly dispersed.
Compositions containing filler, pigment, and
thickeners may be prepared by first charging the calculated
~uantity of water into a suitable tank or container equipped
with an agitator. Aqueous concentrated ammonia is added
to adjust the pH to about 10. Coating filler is added
under agitation. The mixture is agitated until the filler
is completely dispersed. The wax dispersion, containing
the ethylene copolymer, wax, and terpolymer resin are then
added. If a defoamer is necessary, it should be added at
this point. Agitation for 5-30 minutes is usually
sufficient to blend in the dispersion. The pigments are
then added and blended. This step is completed when the
pigmentation of the mixture is homogeneous. The final step
is the addition of the thickener. Agitation of the mixture
; containing thickener should be conducted in such a fashion
as to minimize air entrainment. Removal of the air from
the thickened composition is extremely difficult. When
-17-
:,
~ 1~3717~
the mixture becomes homogeneous after blend~ng in the
~` thickener, the composition is ready for use.
! . After the coating is prepared, it may be applied
to the fabric in a number of ways, such as blading,
1 padding, or any other suitable technique known to those
!~
¦ sk~l~ed in the art. As soon as the coating is applied, it
t i8 desirable to place the coated fabric into an oven or
other suitably heated zone for curing. Curing temperatures
.
1 may range from 300-500F. (149 to 260OC.). m e cur~ng
t lO time i~ related to the o~en temperature. At relatively low
te~peratures~ about 300F. (1~9C.), the curing ti~e is
longer than at relatively high temperatures, about 3~0F.
(193C.). Under most conditions a curing time of 0.5 to 5
~inutes iq sufficient. A low solids composition may require
more curing time than one having high solids because there
i8 more water to remo~e from the coating. Usually in a
blade-coated sample, one minute per side is a sufficient
length of time to cure the coating when the oven tempe~ature
i~ 300 to 350F. (1~9C. to l77C.). When padding
20 (bath technique) is employed, 2 to 5 minutes may be
required at the same temperature. At higher tempera-
tures the curing time can be reduced, but one must use
..
care to avoid degrading the fabric by excessive heating.
Curing can be judged to be complete by determining whether
the coating is wetted when a light spray of water is
directed on the coating.
These coatings have been applied to cotton, poly-
ester (Dacro~a), and nylon fabric. Fabrics composed of
blends of cotton and polyester may also be coated with the
30 compositions of the invention.
Test methods for evaluating performance of
~` .
~,~
'
,1 103717t7
coated fabric of this invention are:
SPraY Ratin~
.
AATCC Test Method 22-1967 ~ASTM D-5~3-63)
HYdrostatic Pressure Test
AATCC Test Method 127-196~ (ASTM D-5~3-63)
J ;Crock Resistance
! AATCC Test Method ~-1969 (1 worst to 5 no crocking)
; Moisture Vapor Transmission Rate
.
- Described by John H. Skinkle, "Textile Testing",
. . ............................. ..
Second Edition, Chemical Publishing Company, Inc.,
; Brook~yn, New York, 19~9, Page~ 96-97.
- in Test~
The rainproof test is conducted by flowing water at a
rat~ of 270 inches (6B5.~ c~.)~hour (1.5 gallon~ (5.6~ 1.)/
~in.) from a height of 60 inche~ (152.4 cm.) onto a fabric
sample ~ inches (20.32 cm.) by 7.5 i~ches (19.05 cm.)
for 30 minutes and measuring the amount of water passing
through the fabric. Fabric that passes less than 100 ml./
30 min. is characterized as having satisfactory rainproof-
ness. ~
Examples l to 19 illustrate the usefulness of
this invention. The compositions of these examples
provide coated fabrics which have a soft, pliable hand.
me last two examples, 20 and 21, illustrate control
compositions. Coating composition 20 contains no ter-
polymer and gives a boardy or harsh hand to a coated
fabric. Coating composition 21 contains no copolymer/
wax component. Fabric coated with composition 21 does
not have satisfactory water repellency.
The formulation components of the compositions
, are given in Table I, Part A. The compositions are
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103717~7
LE 1 . !
Composition 1 was coated by means of a coating
using a 1/~ inch (0.32 cm.) thick aluminum blade mounted
perpendicular to the fabric and parallel to the fill or cross
direction of the fabric. A puddle of coating was maintained
behind the blade and the fabric was passed lunder th~e blade
at the rate of 4.5 feet (1.37 m.) per minute. The coated
fabric was then passed through a heated oven having a
length of 9 feet (2.74 m.) and maintained at 3600F. (1~2C.). -
Fabric width wa:s approximately 15 inches (3~.1 cm.). After~
the goods were coated on one side~ they were turned ow r
and coated on the reverse side. The fabrics coated and
their weight, as well as the properties of the coated
fabrics~ are ehown in Table II.
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' ~03717t7
E~AMPLE 2
Composition 2 had a viscosity of 3,300 cps. at
make up. After five days, the viscosity was 2,900 cps.,
and after twelve days, the viscosity was 2,~00 cps.
EXA~LE 3
Composition 3 was blade coated asldescribed in
Example 1 on several different fabrics as noted below a~d
cured for 1.25 minutes at an oven temperature of 175C. for
each side. The properties of the coated fabric were:
:¦ io F~brlc Wt. Or ~
W~igbt 2 Co~tlng2 S~ray ~t~tlc F~Jt~e~
. Sl~ o~/ya~ oz./yd. tlnR e~....... in. Dry Wet
6.ol 1.95 lOo ~24 .~0 atm.) 4_3 4-3
, ~ ster 6.42 3.o6 100 ~24 .~0 atm.? 4-3 4
ter 6.63 2.77 100 ~24 .~0 atm.~ 4_3 4
~ ~ter 5.94 2.9~ 24 .~0 atm.) 4 5-4
1 19.95 dynes/sq. cm. 5 6.32 dynes/sq. cm.
21.2~ dynes/sq. cm. 6 9.9~ dynes/sq. cm.
3 21.95 dynes/sq. cm. 7 ~.9~ dynes/sq. cm.
20~ 19.62 dynes/sq. cm. ~ 9.64 dynes/sq. cm.
Composition 3 had a viscosity of 2~900 cps. after standing
for 12 days.
EXAMPLE 4 ~~
Composltion ~ had a viscosity o~ 4,600 cps. at
make up and after 12 days, the viscosity was 5,000 cps.
EX~IPLE 5
I Composition 5 had a viscosity of 2,500 cps. at
make up and after 12 days, the viscosity was 3,550 cps.
EX~LE 6
~ 3 Composition 6 was blade coated ~s described in
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103717t7
~xample 1 on 6.7 oz./yd.2 (22.2~ dynes/sq. cm.) cotton
fabric and cured at 175C. for 1.25 minutes. The welght of
the dry coating was 2~3 oz./~yd.2 (7.65 dynes/sq. cm.). me
coated fabric had a hydrostatic pressure of ~24 inches (.B0
atm.) and a spray rating of 100. The viscosity of composi-
tion 6 was 5~100 cps. arter ten days.
EYAMPLE 7
Composition 7 was blade coated as described in
Example } on 6.7 oz./yd.2 (22.2~ dynes/sq. cm.) cotton fabric
and cured at 175C. for 1.25 minutes. The weight of the dry
coating was 2.4 oz.jyd.2 (7.9~ dynes/sq. cm.). The coated
fabric had a hydrostatic pressure Or ~24 inches (.~0 atm.)
and a spray rating Or 100. me viscosity Or the composition
was 4,000 cps. after ten days.
E:gAMPLE ~
Composition ~ pigmented white~ was blade coated
as described in Example 1 on 6.7 oz./yd.2 (22.2~ dynes/sq. cm.)
cotton fabric and cured at 175C. for 1.25 minutes. Weight
of the dry coating was 2.2 oz./yd.2 (7.32 dynes/sq. cm.). The
coated fabric had a hydrostatic pressure of ~24 inches (.gO
atm.) and a spray rating Or 100. The viscosity of the
composition was 4~100 cps. after 9 days.
~A~LE 9
Composition 9~ pigmented white~ was blade coated
as described in Example 1 on 6.7 oz./yd.2 (22.2g dynes/sq. cm.)
cotton fabric and cured at 175C. for 1.25 minutes. Weight
of the dry coating was 2.6 oz./yd.2 (g.65 dynes/sq. cm.).
- The coated fabric had a hydro~tatic pressure of ~24 inches
(.gO atm.) and a spray rating of 100. The composition had
a ~iscosity of 2~00 cps. after 9 days.
-2~-
:103~ 7~7
EXAMPLE lO
Composition lO, pigmented red, was blade coated
as described in Example l on 6.7 oz./yd.2 (22.2~ dynes/sq.
cm.) cotton fabric and cured at 175C. for 1.25 minutes.
Weight of the dry coating was 2.2 oz./yd.2 (7.32 dynes/sq.
cm.). The coated fabric had a hydrostatic pressure of
~ 2~ inches (.~0 atm.) and a spray rating of lO0. The
composition had a Yiscosity of 4,500 cps. after ~ days.
EXL~E 11 '
Composition ll, pigmented red, was blade coated
aæ descr1bed in Example l on 6.7 oz./yd.2 (22.2$ dynes/sq.
cm.) cotton fabric and cured at 175C. for 1.25 minutes.
Weight of the dry coating was 2.5 oz./yd.2 (~.31 dynes/sq.
cm.). The coated fabric had a hydrostatic pressure of ~24
~ inches (.~0 atm.) and a spray rating of lO0. me composi-
I tion had a viscosity of 2~00 cps. after ~ days.
EXAMPL~ 12
Composition 12 was blade coated as described in
Example l on 6.5 oz./yd.2 (21.61 dynes/sq. cm.) cotton
fabric and cured at 175C. for 1.25 minutes. Weight of the
dry coating was 2.5 oz./yd.2 (-~.31 dynes/sq. cm.). The
coated fabric had crock fastness values of 3 (dry) and
3-2 (wet). In the 30-minute rain test, the coated fabric
did not leak. The composition had a viscosity of 3,500 cps.
after 13 dayæ.
EXAMPLE 13
Composition 13 was blade coated as described in
Example l on 6.5 oz./yd.2 (21.61 dynes/sq. cm.) cotton
" fabric and cured at 175C. for 1.25 minutes. Weight of the
dry coating was 2.7 oz./yd.2 (~.9~ dynes/sq. cm.). The
- 29 -
~037~7~7
coated fabric had crock fastness values of 3-2 (dry) and
2-1 (wet). In the 30-minute rain test, the coated fabric
lèaked only a ~ew drops. me composition had a viscosity of
3,800 cp~. after 13 days.
E~AMPLE 14
Composition 14 was blade coated a3 described in
Example 1 on cotton fabric and cured at 175C. for 1.25
minutes. One sample wa~ leached ln water for 16 hours,
and one sample was not. Both samples were sub~ected to a
soil burial te8t for 14 days to determine reslstance to
fungicide attack. Fabrlc strengths of the cured samples
were mea~ured in an INSTRON* Tester at a cro~shead speed of
2 inches (5.08 cm.)/minute. The leached sample exhibited
100~ and 83% strength retentlon in the warp and fill
directions, respectively. The unleached ~ample had 49%
and 36% strength retention in the warp and fill direction~,
respectlvely.
EXAMPLE 15
Composition 15 was blade coated as described in
Example 1 on 6.5 oz./yd. (21.61 dynes/sq. cm.) cotton
fabric and cured at 175C. for 1.25 minutes. me weight
of the coating was 2.3 oz~/yd~2 (7.65 dyne3/sq. cm.). The
coated ~abrlc had a spray rating of 100, a hydrostatic
pressure of 15 inches (0.5 atm.) and crock fastne~s values
o~ 2 (dry~ and 3-2(wet). A coated fabric sample was
~ sub~ected to a 14-day soil burial te~t. me exposed
- fabric had a strength retention of 27% after the burial
test. After 15 days the compo~ition had a visco~lty of
3,500 cps.
* denotes trade mark
-3
.~
1037~7~7
EXAMPLE 16
Composition 16 was blade coated as described in
Example 1 on 6.5 oz./yd.2 (21.61 dynes/sq. cm.) cotton
fabr:Lc and cured at 175C. for 1.25 minutes. The weight of
the coating was 2.7 oz./yd.2 (~.9~ dynes/sq. cm.). me
coated fabric had a spray rating of 100 and a hydrostatic
pressure of 24 inches (0~ atm.). In a 14-day soil
burial test~ the coated fabric exhibited a 7% retention in
strength. The composition had a viscosity of 4~700 cps.
after 15 days.
EXAMPLE 17
Composition 17 was blade coated as described in
Example 1 on 6.5 oz./yd.2 (21.61 dynes/sq. cm.) cotton
fabric and cured at 175C. for 1.25 minutes. The weight
of the coating was 2.5 oz./yd.2 (~.31 dynes/sq. cm.). The
coated fabric had a spray rating of 100 and a hydrostatic
pressure of 1~ inches (o.60 atm.). A 2 inch x 5 inch
(5.0~ cm. x 12.7 cm.) strip of fabric was held vertically
in a flame for 10 seconds. After removal of the flame,
the flame on the coated goods self-extinguished. There
was some afterglow~ which consumed up to one inch (2.54 cm.)
of the base of the fabric.
Composition 1~ was applied to 2 oz./yd.2 (6.65
dynes/sq. cm.) predyed, nylon goods by padding, using
squeeze rolls with 10 pounds (4.54 kg.) total weight on
the roll. The padded samples were cured at 1~0C. for 1.25
minutes. me weight of the coating was 0.25 oz./yd.2 (0.~3
dyne/sq. cm.). me spray rating was 100, and the hydrostatic
pressure was >24 inches (O.g atm.). The coated sample had
~ 0 ~ ~L7~7
a moisture ~apor transmission rate of 756 grams of water
~ ~ per 24 hours per square meter.
i EXAMPLE 19
Composition 19 was blade coated as described in
Example 1 on 6 oz./yd.2 (19.95 dynes/sq. cm.) cotton fabric
and cured at 175C. for 1.25 minutes per side. The weight
of the dry coating was 2.94 oz./yd.2 (9.7~ dynes/sq. cm.).
The coated fabric had a spray rating of 100. The hydrostatic
pressure of the coated fabric was 20 inches (0.67 atm.).
The coated fabric had a soft, pliable hand. me formulated
composition had a viscosity of 3,300 cps. after 1~ days. -A
sample of the coated fabric was leached for 1~ hours in a
tank with fresh water flowing into the tank continuously.
Samples of the leached and unleached fabric were subjected
` to 14-day soil trial tests. After the test~ strength
measurements were made on the fabrics. The unleached
sample had a strength retention of ~4%; the leached sample
had a strength retention of 71%.
EXAMPL$ 20
Gomposition 20 was blade coated as described in
Example 1 on 6.5 oz./yd.2 (21.61 dynes/sq. cm.) 100%
Dacro~D polyester~ woven fabric and cured at 170C. for
1.25 minutes per side. The weight of the dry coating was
~ 2.27 oz./'yd.2 (7.55 dynes/sq. cm.). The coated fabric had
i a spray rating of 90-100 and a hydrostatic pressure of ~ 24
inches (0.~ atm.). The hand of the fabric was boardy,
and the coated fabric had a papery feel.
; EXANPLE 21
Composition 21 was blade coated as described in
30 Example 1 on 7.5 oz./yd.2 (24.94 dynes/sq. cm.) 100%
~,
- -32-
10~7~
Dacro~ polyester, woven fabric and cured at 170C. for
1.25 minutes per side. The dry weight of the coating was
2 oz./yd.2 (6.65 dynes/sq. cm.). The coated fabric
had an excellent hand~ but the spray rating was 50.
.
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,:
-33-
