CA1200337A - Coating composition - Google Patents

Abstract

Abstract of the Disclosure There is disclosed an emulsion coating composition having water dispersed in an organic solvent soluble resin and solvent through the use of an emulsifier having a hydrophile-lipophile balance of from two to about six. The composition may be mixed with a hydro-carbon propellant miscible in the continuous phase in suitable con-tainers to produce a non-foaming water containing aerosol spray paint or varnish.

Description

COATING ~,O~POSITIO~

Back~round of the Invention The present invention relates generally to coatin~
compositions and specifically to a solvent soluble resin paint or varnish having water dispersed ~herein.

It has been a desideratum in the coatings art to formu-late a paint, varnish or other protective coating composition which employs an organic solvent soluble film-forming component and which further includes water as part of the evaporative vehicle.

Presently such compositions, commonly called solvent or solution resin coatings, comprise organic solvPnts as the evaporative vehicle, often in amounts in excess of 60% of the total composition. As this solvent evaporates during the drying of the coating, consi-derable irritation and odor may be caused by the escape of these fumes in the atmosphere. Also, organic sol-vents are not inexpensive, and contribute substantiallyto the cost of the coating composition. In addition, as organic solvents are highly flammable they are haæardous during the manufacture and use of the coatings, and add to the fireload and insurance costs of manufac-turing and warehouse facilities. For these reasons, ithas been desirable to substitute water for part of the solvents previously employed.

Heretoore, water containing coatings have required water soluble or dispersable film-forming components, and latex paint, for example, has met with wide acceptance.
Latex paint is composed of two dispersions. First, a dispersion of pigments and various extenders in water, and second; a dispersion of the resin in the water. The `~ 35 resin dispersion is either a latex formed by emulsion ~ .
~-.

~.,.

~3~33'7 polymerization or a resin in emulsion form. Such paints are characterized by the fact ~hat the film-forming component is in a water-dispersed form. The principle film-for~ing components in latex paints are styrene-butadiene, polyvinyl acetate, and acrylic resins.

However, latex coating compositions are not without ~heir disadvantages, First, as the latex composition is a double dispersion, it requires two emulsifiers which may conflict and may, in particular, cause prob-lems in formulation due to the fact that the emulsifier used in the polymerization of the resin may be un-known and have an unpredictable effect on the final product. In addition, the oil-in-water emulsion found in latex compositions will not dry to produce the clear or gloss finish found in solvent coatings such as varnish and the like. Oil-in-water emulsion clear coatings, due to the latex resins used, tend to form with brush marks or surface disruptions and cannot be easily sanded or otherwise refinished as can traditional solvent varnishes.

Also, latex coatings are not easily adaptable to use in pressurized cans commonly referred to as aerosol containers~ This is due to the high viscosity of the late~ composition and the tendency of the latex oil-in-water emulsion to foam excessively when sprayed from an aerosol container. This foaming begins, as the composi-tion leaves the nozzle and becomes apparent after th~
coating has been applied to the substrate or workpiece, ~or example, previous water base spray pain~s dry with small craters rather than a smooth surface which indi-cates that foaming has occurred during the application process. Thus, when the foam dries there is left a ,~; 35 penetrable film which seriously affects the protective .. . . ... . _ _ . .. . . . . _ , " ~2S~337 value of the coating. In addition, as the propellant must be mis-cible in the continuous phase in order to properly atomize the emulsion for spraying, suitable i.e. water soluble propellants have led to an excessive product cost and have been otherwise unsatisfactory.

Summary of the Inve tio This invention comprises a water-in-oil emulsion coating composi-tion having a continuous phase including an organic solvent and a film-forming resin dissolved in said solvent, with water dispersed in the continuous phase through the use of a suitable emulsifier The composition rnay be applied by brush, roller or compressed air spraying apparatus as well as being advantageously suited to being sprayed from aerosol containers such as by the inclusion of an oil-phase soluble propellant. As hereinafter described, the water-in-oil emulsion is maintained through the use of an emulsifier or an emulsifier system having a hydrophile-lipophile balance, or EILB
value, of from two to about six.

Among the advantages of the present composition is that water is substituted for a large proportion of the evaporative vehicle in traditional solvent coating compositions. Thus, the invention allows the known advantages of solvent resin films to be retained in a composition havlng the benefits of a water base product, and a wide range of resins, including any organic solvent Eilm-forming resin, ma~ be used.

Substantial cost savings are atta.ined because of the lower cost of 33~
-3a-water as compared to organic solvents. The hazards and costs of unneeded flammable solvents are also markedly reduced. Cost sav~
ings are further realized since the traditional organic solvent soluble resins are often less expensive than the resins heretofore used in latex oil~in-water emulslon pain~s. The ~resent invention also enhances the functional utility of the ~int as the resultant film ~ay be sanded, stripped or otherwise re-finished throup,h the use of traditional methods.

The water-in-oil emulsion of the present invention may be sprayed from aerosol con~ainers, which are known in ~he art, and atomizes readily upon spraying to produce a smooth, non-foaming coating on the workpiece to which it is applied.

The coatings referred to herein and the compositions contempla~ed by the present invention include those products ~nown as varnish, paint, enamel, primers, lac-quer and commercial protective coatings or any coating or composition wherein the film-forming resin is organic solvent soluble and which will form a water-in-oil emul-sion as hereinafter described.
Description of the Preferred Embodiment The percentages expressed herein, both in the specifica-tion and the claim~ appended thereto, are intended and expressed as percentages by weight of the total composi-tion to which they refer.

Solvents which are contemplated by and have been found useful in the present invention include aliphatic and ar~matic hydrooarbons, esters, ketones, glycol ethers and alcohols having a distillation range of from 100 to 500 ~, Although any organic solvent soluble film`forming resin is suitable for use in the present invention, resins ~hich are preferred for use in the water-in-oil emulsion ~$~337 system are those with the greatest resistance to hydrolysis.
Aliphatic and aromatic hydrocarbon resins possess this character-istic to a high degree, as do vinyl toluene and styrene modified resins. Epoxy ester resins also have a high resistance to hydro-lysis because of the ether groups in the molecule and resultant steric hindrance found in these resins.

The water-in-oil emulsion of the present invention is adaptable to produce varnishes, wherein a clear or gloss coating is produced from the polymerization of the resin or the evaporation of the volatile portion of the vehicle. Paints such as enamels may also be produced by the addition of various organic and inorganic pig-ments, including carbon black, and both natural or synthetic oxides and other known colorants as hereinafter described, along with conventional pigment dispersants and anti-settling agents.
Additional ingredients known in the art may also be added, such as mar resistance agents and drier catalysts.

Water is dispersed in the oil phase according to the present inven-tion, dependent upon the required coating composition or use, in any ratio which allows the coating to form. Specifically, water has been dispersed in amounts of up -to 80% of the liquid composi-tion through the use of appropriate emulsifying agents. Emulsi-fiers which have been found useful in the formation of the composi-tion of the present invention are emulsifiers having a hydrophile-lipophile balance number of from one/half to twelve.

me HLB system is a semi-empirical procedure for the selection of an appropriate emulsifier. The procedure is based on the concept that the molecule of any emulsifier contains both hydrophobic and hydrophilic groups, and the ratio of their respective weiyht per-centages should influence emulsification behavior.

The HLB value can be calculated from the theoretical composition of the emulsifier. For example, in determining the HLB for ethylene oxide condensation products, HLB equals one-fifth of the weight percent of the oxyethylene hydrophlic content of the mole-cule. The HLB of ester emulsifiers may be calculated by the formula HLB=20 (1-S/A), wherein S is the saponfication of the emulsifier and A is the acid number of the fatty acid moiety.
Such methods of calculation are known in the art and expressed in a wide variety of publications.

HLB values have also been determined by titration, spreading coefficients, gas-liquid chromatograph -techniques and other labora-tory methods. Generally, suppliers of commercial proprietary emulsifiers provide an HLB number for their products, and published HLB indices of these materials are known in the art.

According to the present invention, a single emulsifier having an ~I,B of from two to about six may be used. However, it is prefer-able to use a blend of emulsifiers, including a continuous phasecomponent as well as an emulsifier for the dispersed phase, which produce an emulsifier system having an HLB of from two to abou-t six. When two or more of these emulsifiers are to be blended the HLB of the combination is calculated by the formula xA+(l-x)B

wherein x is the percent proportion of the emulsifier having an HLB of A and B is the HLB of the second emulsifier~ It has been ~L~S~337 -6a-found that the most stable emulsion systems consis-t of blends of two or more emulsifiers, one portion having lipophilic tendencies (HLB 0.5 to 5.0), and the other portion having hydrophilic tendenc-ies (HLB 5.0 to 12.0).

~., 33~;) Example One A gloss black enamel was prepared having the following composition:
Carbon black 1.1 %
Vinyl toluene modified alkyd resin 9.5 %
Aromatic hydrocarbon resin 5.7 %
VM & P Naphtha lS.4 ~/D
Toluol 5.7 %
Xylol 3.2 %
Aliphatic hydrocarbon solvent, boiling range, 300-400~ F. 28.4 %
Pigment dispersant (Nuosperse 657) 0.1 %
Anti-settling agent 0.1 %
Mar resistanee agent 0.3 %
Drier catalyst 0.1 %
Sorbitan trioleate (Span~85, HLB 1.8)0.32%
Polyethylene glycol monooleate (Mapeg~200 MO, HLB 8.0) 0.08%
Water 30 0 %
100 . 00%

The composition was prepared by first combining the pig-ment, pigment dispersant, anti-settling agent and a ~5 portion of the resin and solvent in a mixing vessel as is known in the art. I`he mixing was continued until the pigment was dispersed ~o a suitable degree of fineness. Thereafter, the remainder o the resin and solvent was added along with the mar resistance agen~
an'd drier catalyst. When the mixing was completed, the oil dispersable emulsifier, HLB 1.8, was stirred into the enamel with a homogenizer-type intensive mixer.
After five minutes of mi~ing, a solution of~water and the water dispersable emulsifierl HLB 8.0 is poured into the enamel while under constant mixing. These two emulsifierc as hereinbefore described, yielded a total ~ T~ ~4a~k emulsifier syst~m value of 80% x 1.8 ~ 20% x 8.0 - 3.04.
The wa~er-in-oil emulsion was formed within five to te~ minutes.

Example Two In a like manner, varnish compositions may be made using the same ingredients, with the omission of the carbon black pigment and pigment related additives. Speci~ically, a varnish was made having the following composition:
; Oil modified polyurethane resin (Urotu ~13-309) 13.9%
Mineral ~pirits ~boiling range 307-389 F.) 13.9%
Aromatic solvent ~SC-100, boiling range 311U-344 F.) 31.7%
Aromatic sol~ent (SC 150, boiling range 352-410 F.) 9.4%
Drier catalyst 008%
~0 Anti-skinning agent ` 0.~%
Polyoxyethylene so~b;tol beeswax derivative (Atla~G-1727, HL~ 4.0~ 0.2%
Water . 30.0%
100, 0%
~5 SC-100 and SC-150 are known naphtha mixtures containing 98% aromatic material of C8 or higher. Aliphatic naph-thas of like boiling ranges may be used and are intended as equivalent.
Example Three According 'co t-he-same method, a gloss white enamel was prepared ha~ing the following composi~ion:
T~

~2tJ~3~

Titanium dioxide 11.0 %
Vinyl toluene modified alkyd resin 14,7 ~/0 VM & P Naphtha 14 . 5 %
Aliphatic hydrocarbon solvent, boiling range, ~11-344 D F. (SC-100) 19 6 %
Xylol 7.5 %
Pigment dispersant (Disperse Ayd No. 1) 0.2 %
Anti-settling agent 1. 8 %
Mar resistance agent 0.3 %
Drier catalyst 0.1 %
Sorbitan trioleate (Span 85, HLB 1.8) 0.25%
Polye~hylene glycol monool~ate - (Mapeg 200 MO, HLB 8.0) 0.05%
Water 30.0 %
100.0 ~/0 The compositions described above in examples one through three were each further processed to form aerosol spray coating compositions. After the water-in-oil emulsion described above is formed, the composition was packed in an aerosol can with a suitable propellant, here pro-pane or a mixture of propane, isobutane and/or butane ?5 as known in the art. The amount of propellant may vary in accordance with the intended result, but is generally in the ratio of twenty to thirty-five percent propellant by weight in relation to the total composition. A metal or glass object weighing from ~ive to ten grams is cu~-tomarily added to the can along with the enamel. Thisobject serves as an aid ;n mixing the pigmçnt, if any, which settles to the bottom of the can during storage.

Example Four Black Enamel using an aromatic hydro~arbon resin:

~'h~33~

Carbon black 1.2 %
Aromatic hydrocarbon ~esin 19.6 %
: Toluene 23.4 %
Hexane 4.9 %
Aromatic solvent, ~oiling range 300-400D F, 20.0 %
Plgment dispersan~ (Nuosperse 657)0.1 %
Anti-settling agent 0.2 %
Mar reslstance agent O.l %
Drier catalyst 0.1 %
Sorbitan sesquioleate ~Liposorb SQ0, HLB 3,7~ 0.32%
Diethylene glycol fatty acid ester (Emcol DP-S0, HLB 5.1) 0.08%
W~ter 30.00%
100 . 00%

Example Five 20 White Ground Marking Paint using an aromatic hydrocarbon resin:
Titanium dioxide 11.34%
Calcium carbonate 2.59%
Aromatic hydrocarbon resin 14.06%
Toluol . 14.72%
Aromatic hydrocarbon solvent, boiling range 311 344 F, (SC~lO0~ 4.47%
Anti-settling agent 1.0270 Drier catalyst 0~.22%
Pigment dispersant (Nuosperse 557) 0.34%
Sorbitan trioleate (Span 85, I~B 1.8) 0.24%
Polyethylene-glycol monoolea-te --- - -(M~peg 200 M0, HLB 800) Q.06%
Water . . 50.94%
100 . 00%

It has been found that when water is used in excess of 60%, particularly when dispersed in resins having a hi:gh viscosity at high solids conten~, a high viscoslty emulsion is produced ~ue to the reduction of the ef-fective amount of solvent for the resin and the internalfriction created by the emulsified water. Thus, while hi~h water content may ~e advantageous in brushed coa~ings or industrial s~ray applications, lower vis-cosity emulsions should ~e used in the aerosol spray compositions of the present invention.

Exal~le Six .

Red Enamel using an epoxy ester resin:
Toluidine Red 1,9 %
Epoxy ester resin 14,8 %
Xylol 15.9 %
Aromatic solvent, boiling ; range 311~340 F, (SC-100) ~ 35.3 D/o Pigment dispersant (Nuosperse 657) 0.06%
~nti~settling agent 0.2 %
Mar resistance agent 0.1 %
Drier catalyst 1.0 %
Anti-skinning agent 0.3 %
Sorbitan tristearate (Liposor ~ TS, HLB 2.1) 0.56%
Polyethylene glycol 200 dilaurate (Emerest~ ~22, HLB 6,2) 0,08%
Water 29.8 %
100.~0%

Example Seven Red Fluorescent Paint using an acrylic resin:
~ ~a~
... ., . . . .,~

12~1C1 33 7 -~2-Red Fluorescent Pigment 1~,8 %
Acrylic resin 4.2 %
; Aliphatic hydrocarbon solvent, boiling range 150-200 F. 37.0 %
Xylol 15.6 %
Sorbitan trioleate (Span 85, HLB 1.8~ 0~35%
Polyethylene glycol monooleate (Mape~ 200 MO, HLB 8.0~ 0.09%
Water 29.96%
100 . 00%

ExamPle Eight Red Iron Oxide Primer using an ~poxy Ester:
Red Iron Oxide 5.4 %
Yellow Iron Oxide 1.6 ~/O
Magnesium Silicate 6.8 %
Zinc Phosphate 2.6 %
Carbon Black 0.2 %
Epo~y ester resin 8.7 %
Xylol 30-4 /o Toluol 11.2 %
Anti-skinning agent 0.03%
Pigment dispersant (Nuosperse 657)0.15%
Anti-settling agent 2.12%
Drier ca~alysts 0.40%
Ethylene glycol distearate (Emerest 2355, HLB 1.2) 0,34%
~ Polyethylene oxide sorbitan tristearate (Liposorb TS-20, HLB 10.5) 0.0~%
Water 29.97%
100 . 00~

.. . _ __ . _ _ ~ . ~. .,____ _~. _ ._ ._ ,.. . . . _ _ .. .. ... ___ ~ . . .... .

Each of the compositions hereinbefore described pro-vided a coatin~ comparable to the solution resin co~tings as previously known at a markedly lower cost due to the inclusion of water in the composition, The amount of water in the composition is dependent upon the type of film desired and ~ay vary up to 80% of the total conposition.

Further, each of the compositions, when s~rayed from a standard aerosol container, resisted foaming and formed a smooth, continuous coating heretofore unobtainable in an aerosol water containing paint.

F~rther compositions were made including standard ~aria-tions in the percentages of resin, solvent, pigments and other additives as known in the art. Oil modified polyurethane resins, epoxy ester resin, aromatic hydro-carbon resin, aliphatic hydrocarbon resin, vinyl toluene modified oil, solution vinyl resin, silicone resin and solvent soluble acrylics may be selected in accordance with the requirements of the desired application.

From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of the invention! and without departing from the spirit and scope thereof, can make various changes and modifications to adap~ the invention to various usages and conditions.

Claims (16)

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

1. A water-in-oil emulsion coating composition comprising: (a) a continuous phase, said continuous phase including a solvent; (b) a dispersed phase, said dispersed phase, including water; (c) a film-forming resin, said resin being dissolvable in said solvent, said continuous phase further including an effective amount of said resin for forming a film on a workpiece; and, (d) an emulsifier, said coating composition including an effective amount of said emulsifier for effecting stable dispersion of said dispersed phase throughout said continuous phase, whereupon said coating composition has as much as 80 percent water on a weight basis, said water thereby serving to extend said solvent as to said coating composition throughout said coating composition.

2. The coating composition of claim 1 wherein said emulsifier has an HLB value of from about 2 to about 6.

3. The coating composition of claim 2 wherein said film-forming resin is selected from the group consisting of modified vinyl-toluenes, oil-modified polyurethanes, modified styrenes, epoxy esters, solution vinyls, silicones and mixtures thereof.

4. A water-in-oil emulsion coating composition comprising: (a) a continuous phase, said continuous phase including a solvent; (b) a dispersed phase, said dispersed phase including water; (c) a film-forming resin, said resin being dissolvable in said solvent, said continuous phase further including an effective amount of said resin for forming a film on a workpiece; and, (d) an emulsifier system, said coating composition including an effective amount of said emulsifier system for effecting stable dispersion of said dispersed phase throughout said continuous phase, said emulsifier system including at least two emulsifying components, a first emulsifying component having an HLB value of from about 1/2 to about 5, a second emulsifying component having an HLB value of from about 5 to about 12, an HLB value for said emulsifier system being a weighted average of said respective HLB values of said first and said second emulsifying components, said emulsifier system having an HLB value of from about 2 to about 6, whereupon said coating composition has as much as 80 percent water on a weight basis, said water thereby serving to extend said solvent as to said coating composition throughout said coat-ing composition.

5. The coating composition of claim 4 wherein said film-forming resin is selected from the group consisting of modified vinyl-toluenes, oil-modified polyurethanes, modified styrenes, epoxy esters, solution vinyls, silicones and mixtures thereof.

6. The coating composition of claim 3 or claim 5 wherein said solvent has a distillation range of from 100 to 500 degrees Fahrenheit.

7. The coating composition of claim 3 or 5 wherein said solvent has a distillation range of from 100 to 500 degrees Fahrenheit and is selected from the group consisting of esters, ketones, glycol ethers, alcohols and mixtures thereof.

8. The coating composition of claim 3 or 5 wherein said solvent has a dis-tillation range of from 100 to 500 degrees Fahrenheit and is selected from the group consisting of esters, ketones, glycol ethers, alcohols and mixtures thereof and wherein said continuous phase includes an effective amount of paint pigment particles for providing a desired color, said continuous phase further including an effective amount of a pigment dispersant for effecting stable dispersion of said pigment particles throughout said continuous phase.

9. The coating composition of claim 8 wherein said coating composition ranges from about 29 to about 51 percent water on a weight basis.

10. A method of manufacturing a water-in-oil emulsion coating composition, said coating composition having a continuous phase and a dispersed phase, said continuous phase including a solvent, said dispersed phase including water, said coating composition including an effective amount of an emulsifier for effecting stable dispersion of said dispersed phase throughout said continuous phase, said method comprising: (a) adding to said solvent an effective amount of a film-forming resin thereby producing a mixture, said resin being soluble in said solvent; and (b) adding to said mixture a first effective amount of said emulsifier and to a dispersible phase a second effective amount of said emulsifier for effecting stable dispersion of said dispersible phase throughout said continuous phase and thereafter combining said dispersible phase and said mixture thereby producing said water-in-oil emulsion which is capable of forming a film on a workpiece, said emulsifier having an HLB value of from about 2 to about 6, whereupon said coating composition has as much as 80 percent water on a weight basis, said water thereby serving to extend said solvent as to said coating composition throughout said coating compo-sition.

11. The method of claim 10 wherein said film-forming resin is selected from the group consisting of modified vinyl-toluenes, oil-modified polyurethanes, modified styrenes, epoxy esters, solution vinyls, silicones and mixtures thereof.

12. A method of manufacturing a water-in-oil emulsion coating composition, said coating composition having a con-tinuous phase and a dispersed phase, said continuous phase including a solvent, said dispersed phase including water, said coating composition including an effective amount of an emulsifier system for effecting stable dispersion of said dispersed phase throughout said continuous phase, said emulsifier system including at least two emulsifying components, a first emulsifying component having an HLB value of from about 1/2 to about 5, a second emulsifying component having an HLB value of from about 5 to about 12, an HLB value for said emulsifier system being a weighted average of said respective HLB values of said first and said second emulsifying components, said method com-prising: (a) adding to said solvent an effective amount of a film-forming resin thereby producing a mixture, said resin being soluble in said solvent; and, (b) adding to said mixture an effective amount of said first emulsifying component and to a dispersible phase an effective amount of said second emulsifying component for effecting stable dispersion of said dispersible phase throughout said continuous phase and thereafter combining said dispersible phase and said mixture thereby producing said water-in-oil emulsion which is capable of forming a film on a work-piece, said emulsifier system having an HLB value of from about 2 to about 6, whereupon said coating composition has as much as 80 percent water on a weight basis, said water thereby serving to extend said solvent as to said coating composition throughout said coating composition.

13. The method of claim 12 wherein said film-forming resin is selected from the group consisting of modified vinyl-toluenes oil-modified polyurethanes, modified styrenes, epoxy esters, solution vinyls, silicones and mixtures thereof.

14. The method of claim 11 or claim 13 wherein said solvent has a distilla-tion range of from 100 to 500 degrees Fahrenheit.

15. The method of claim 11 or 13 wherein said solvent has a distillation range of from 100 to 500 degrees Fahrenheit and is selected from the group con-sisting of esters, ketones, glycol ethers, alcohols and mixtures thereof.

16. The method of claim 11 or 13 wherein said solvent has a distillation range of from 100 to 500 degrees Fahrenheit and is selected from the group con-sisting of esters, ketones, glycol ethers, alcohols and mixtures thereof and wherein said coating composition ranges from about 29 per cent to about 51 per cent water on a weight basis.