CA1037177A

CA1037177A - Ethylene copolymer dispersions as water repellent coatings

Info

Publication number: CA1037177A
Application number: CA198,609A
Authority: CA
Inventors: Roland E. Stahl
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1973-04-30
Filing date: 1974-04-29
Publication date: 1978-08-22
Also published as: FR2227286B3; BE814440A; NL7405770A; FR2227286A1; DE2420971A1; IT1010231B; GB1427488A; JPS5014729A

Abstract

TITLE

Ethylene Copolymer Dispersions As Water Repellent Coatings ABSTRACT
An aqueous ethylene copolymer dispersion, from which an improved water-repellent coating can be applied, is provided. The dispersion comprises an ethylene co-polymer, a wax and a terpolymer of vinyl acetate, ethylene and N-methylol acrylamide. A fabric having thereon a coating of the dispersed phase of the dispersion and a process for preparing the coated fabric are also provided.

Description

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) ~ 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~
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 :

.

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 .~ .-~ .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 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 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 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.

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 :, ~ 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 .

~) -19--103717~7 ~
summarized in Table I, Part B. Viscosities were eter-ined usi~e ~ Dr~o}fi-ld LVT, 6 rp., No. 3 ~ indle ' , ' , . ~ .

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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:
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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 : ' , :

v -27-~s 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.

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.

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 ~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.

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 .~

1037~7~7 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.

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%
~, 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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Claims

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:

1. An aqueous dispersion comprising a mixture of (1) an ethylene copolymer comprising at least 30 percent by weight ethylene and up to 70 percent by weight of an alpha,-beta-ethylenically unsaturated carboxylic acid, 0 to 75 percent of said acid groups being neutralized with alkali metal ions, and a paraffin wax, the dry weight ratio of wax to ethylene copolymer being 1:1 to 19:1, and (2) a terpolymer emulsion comprising ?? to 77 percent by weight vinyl acetate, 20 to 30 percent by weight ethylene and 3 to 6 percent by weight N-methylol acrylamide.

2, A dispersion according to Claim 1 wherein the ethylene copolymer comprises at least 70 percent by weight ethylene and up to 30 percent by weight methacrylic acid.

3. A dispersion according to Claim 1 wherein the carboxylic acid has from 40 to 75 percent of its acid groups neutralized with alkali metal ions.

4. A dispersion according to Claim 1 wherein the dry weight ratio of wax to ethylene copolymer is about 1.5:1 to 6:1.

5. A dispersion according to Claim 1 wherein the dry weight ratio of ethylene copolymer and wax dispersion to terpolymer emulsion is from 70:30 to 20:80.

6. An article comprising a textile having there-on a coating of a dispersion phase of the dispersion according to Claim 1.

7. An article comprising a textile having thereon a coating of a dispersed phase of the dispersion according to Claim 2.

8. An article comprising a textile having thereon a coating of a dispersed phase of the dispersion according to Claim 3.

9. An article according to any one of Claim 6, Claim 7 or Claim 8 wherein the textile is cotton, polyester, nylon and blends of cotton and polyester.

10. A process for preparing a water-repellent fabric comprising applying to the fabric a dispersion of Claim 1 and applying heat until the water is vaporized and the coating is cured.

11. A process for preparing a water-repellent fabric comprising applying to the fabric a dispersion of Claim 2 and applying heat until the water is vaporized and the coating is cured.

12. A process for preparing a water-repellent fabric comprising applying to the fabric a dispersion of Claim 3 and applying heat until the water is vaporized and the coating is cured.

13. A dispersion according to Claim 1 wherein the wax is a paraffin wax of petroleum origin.