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Distribution on Last Page Report No, R-68-9 LIMITED DISTRIBUTION File: 1865 E. I. du Pont de Nemours & Company F. & F., Research Division Marshall Laboratory sarch Report EMULSION PAINT RESEARCH - IV Date Issued Period Covered Project No, Previous Reports Notebook Nos, February 8, 1968 6/67 - 1/68 P-13226 R-64-33, R-65-22, R-65-112, r -66-59, R-66-126, R-67-54 8986, 9115 ABSTRACT The problems of obtaining better flow and appearance in dripless flat paints of the "Lucite" Wall Paint type are discussed. Leads are given for improving the leveling and hiding power and for de creasing cost but with a sacrifice in driplessness. Flat emulsion house paints based on the emulsions used in ''Lucite1' Interior and Exterior Enamels (10-4 & 10-3) have better leveling and appear ance. However, these failed worse than #50 "Lucite" House Paint when exposed over a badly flaked old paint substrate. Higher gloss and improved water resistance have been obtained for 10-3 Acrylic Emulsion Paints. These dry sufficiently hard for taping in about 4 hours at room temperature. Nonionic surfactants of the Triton type which differ only in chain length have vastly different effects on viscosity, driplessness, leveling, spackle cracking and stability to ions. MJM/dcy 1/31/68 PREPARED BY; ^ 9 ' M. J,, McDOWELL N41538 EMULSION PAINT RESEARCH INTRODUCTION: In previous reports (Ref. 1, 2* 3) techniques were described for improving the leveling and lapping of semi-gloss emulsion paints. The recently commercialized Lucite Interior Enamels were the first products to use these new techniques. In the present report attempts are described to extend the new formulating approach to our most important con sumer paints - ''Lucite" House Paint 5s 1'Lucite" Wall and Ceiling Paints. Also included are descriptions of the following research (1) Improving the leveling of dripless paints (2) Decreasing cracking over spackle (3) Increasing the hiding power (4) Increasing the coalescence and hardness of high gloss emulsion paints (5) The role played by nonionic surfactants tin thick ening , stability and adsorption. OBJECTIVES: The goals are to develop information on important emul sion paint phenomena and to see that the information is used to improve existing products and to design new products. SUMMARY AND CONCLUSIONS: Wall Paints Leads are desirable for a new generation of "Lucite" Wall Paints which will maintain the advertised features of driplessness* ease of application* etc.* but which will have im proved flow and appearance. The problem is that for driplessness we need a pseudoplastic paint with appreciable yield value and a high viscosity at low shear rates. These properties are the opposite of those required for good leveling* absence of brushmarks* roller patterns, etc. An experimental dripless paint which showed improved leveling when brushed was formulated. It was based on a higher viscosity modification of 10-3*thickened with the Veegum montmorilIonite clay used in 392-Line "Lucite" paints. The formu lation is impractical in that it does not level when rolled and its viscosity increases on the shelf. its viscosity is higher than "Lucite" except at the low shear rates that control leveling Its viscosity at 0.1 sec."1 decreases from 800 to 400 poise when the measurement is made after first shearing at 529 sec."1. *10-3 =MMA/2EHA/MAA emulsion = 47.5/49.5/3 -2- Apparently the shear under the brush but not under the roller is sufficient to reduce the viscosity and allow surface ten sion forces to cause flow and leveling. There are at least 3 types of important dripping. Blobs of paint drop from a brush dipped into the can, paint runs down the handle of a brush especially when ceilings are painted, and splatters of paint are flicked off a brush or roller during application. The rheology required to prevent each type of dripping seems to be different. If we achieve improved leveling by formulating a paint whose yield value and viscosity at low shear rates are lowered by shearing during use, it will probably run down the handle of the brush to a greater extent than present "Lueite". An improved balance between good leveling, splatter resistance and low cost is possible with high can consistency paints (110 Krebs Units) based on 10-4* and Thickener LN. Cost can be reduced still further by using a lower cost, harder, royalty-free iminated acrylic emulsion (RC-B-91484) methylmeth acrylate/2 -ethyihexylacrylate/methacrylic acid ** 60/36/4 with a low cost external plasticizer. The advantages of this type of paint over "Lueite" Wall Paints are lower cost, improved appearance, reduced cracking and peeling. The rheology is similar to that of the new emulsion semi-gloss paints i. e., higher viscosity at intermediate shear rates, lower viscosities at very low and very high shear rates and lower yield value than "Lueite" Wall Paints. The dry hiding power can be increased and the hiding power loss on drying can be decreased in ''Lueite" Ceiling White by adding extender to increase the pigment volume concentration or by replacing the present "Ti-Pure' R-901 with new, still experimental Ti02 s irom Pigment Department. House Paints Flat emulsion house paints have been formulated with much better leveling and slightly better build than #50 "Lueite" House Paint. When these were compared with #50 for durability over cracked old oil paint, they were superior on the weatherometer but inferior when exposed 45 South in Delaware in December, 1966. A house paint based on 10-4 and a small amount. of Thickener LN cracked worse than those based on 10-3** or 10*** which contained five times as much Thickener LN. Additional ex posures have been made of the softer 10-3 emulsion in formula tions containing both propyleneglycol and ethyleneglycol mono ethyl ether for improved coalescence and adhesion. *10-4 iminated MA/2EHA/MAA48/48/4 **10-3 = n n n 18 47,,5/49/5/3 *** IQs 19 88 M **45/53/2 -3 Gloss Emulsion Paints High gloss acrylic emulsion paints which should have good durability even when dried at low temperatures have been formulated from 10-3 with Amberlac 165 added for hardness and early tapeability. Propyleneglycoiordiethyleneglycol monobuteyl ether greatly improve the water resistance of these paints probably because of improved coalescence. Nonionic Surfactants Nonionic surfactants differing only in chain length have vastly different effects on viscosity, leveling, spackle cracking and ionic stability. The ataount adsorbed on emulsion particles has been determined. ACTION TAKEN OR PROPOSED: We have proposed that the composition of #50 "Lucite" House Paint, which is durable enough according to Marketing (Ref. 14) be changed as little as possible to obtain better leveling and slightly better build. The smallest changes which give these properties involve adjusting the monomer ratio from the present 45/53/2 (MMA/2EHA/MAA) to 45/52/3 and replacing methylcellulose with Thickener LN. Two 4 gallon batches of paint with this composition were made and given to W. D. Deveise and W. J. Starr for exposure testing. Suggestions in the form of Backlog Proposals (#67-rl0 and Ref. 15) have been made for studying "Penetration of Emul sion Paints in Porous Surfaces" and "Improving our Patent Posi tion in Emulsions". We propose to continue this project with emphasis on learning how to improve the texture of "Lucite" Wall Paint with out sacrificing driplessness. G. C. Bell under his Distributive Project will evaluate methods for measuring low shear rate viscosity and yield stress immediately after shearing. He also plans to determine how the rheology of a paint affects the so-called brush-drag, the cushion and the applied film thickness. PATENT STATUS: Status of Prior Proposals No office action has been received on FFD-1240 (Water Base Paints having improved leveling and lapping.) The present -4" plan is co refile as FFD-1240A, when an office action on FFD1240 is received to cover the additional classes of thickeners mentioned in M. J. McDowellto C. E. DeBoer 9/22/66. Patent Proposal FFD-1253 which covers Mesirov's brushdrag compositions containing polyethyleneiraine has been filed mainly because of Elchem's interest in polyethyleneimine-modi fied vinyl acetate copolymer paints. The following are the imination patent proposals and their corresponding U.S.P. numbers - FFD-3006A FFD-1218A FFD-1222 FFD-3046 FFD-2048A FFD-1834 U.S. 3,261,796 (Dow have initiated an interference on this patent). U.S. 3,309,331 U.S. 3,261,797 U.S. 3,261,799 The patent office has indicated that the 13 claims will be allowed. Formerly F970A covers iminated carboxylic acrylic solution copolymers and adhesive compositions. FFD-1192 Acrylic copolymer Latex Paint Modified with Benzophenone has issued as U.S. 3,320,198. New Proposals Refiling FFD-1240 to cover paints containing new classes of thickeners has been proposed . FFD-1821 proposed claiming "Treatment of High Acid Number Oil Modified Alkyd Resins with an Aziridine Compound". This pro posal which has electrodeposition implications was forwarded to Legal on 2/8/67. Competitive Patents Two patents on thickeners U.S. 3,301,829 and U.S. 3,306, 863 have issued assigned to General Aniline and Geigy Chemical Corp. respectively, U.S. 3,301,829 claims 18. "A composition comprising a water-soluble partial ester of: (1) a micelle-forming hydroxyl-containing non-ionic surface active agent selected from the group consisting of alkylene oxide condensation products with an active hy drogen-containing hydrophobe, alkylolamine condensation products with fatty acids, alkylolamine condensation products with fatty esters, and glycol and polyesters of fatty acids and -5~ (2) an alkali-*soluble interpolymer of an ethylenically unsaturated carboxylic acid anhydride with a terminal ethylenically unsaturated copolymerizable monomer selected from the group consisting of vinyl ethers, vinyl esters and -olefins, said partial ester con- . tainting from about 0*1% to about 3% of the carboxyl _groups as ester groups." i ~ 20s "A composition as defined in claim 18 wherein the surface active agent is an alkyl phenol-ethylene oxide condensate and the interpolymer is a vinyl methyl- ethfef-maleic anhydride interpolymero" We concur with G* E Bartsch that Claim ,20 "appears to rather specifically cover compounds of the Thickener L type*" General Aniline informed us they would sell Gantrez AN-119 and include in the purchase price a royalty for a non exclusive license to manufacture partial esjter^compos it ions under U.S* 3,301,829 (See M. J* MeD* to J* 17. B* 7/7/67). On 11/21/67 we requested (ref* 18) General Aniline to provide in formation on the amount of royalty and whether an unlimited license was available* No reply has been received yet* The U*S,, 3,306,863 patent assigned to Geigy claims ethylene/ttaleie anhydride/Triton X-100 thickeners and discloses the use of styrene/maleic anhydride based thickener which are superior to Thickener LN (ref* 19, 3, 20). Use in latex paint and pastes for textiles is disclosed* Advantages claimecTare improved color value, better wash fastness, improved cracking resistance, lower solids, improved hand, etc. r U:*Stt 3,291,930 assigned to Koppers claims thickeners for latiees based on styrene/maleic acid ester'ified with small amounts (1-5%) of the polyethylene ethers of monohydrie aliphatic alcohols* These were prepared in the dry state of in toluene* UiiSjj 3,290,416 (12/6/66) assigned p6 Pittsburgh Plate Glass, is directed to solution acrylic polymers' modified with propyleneimine and "could be recognized as dominating 10 latex." However it appears that we have a basis fbr Tguoring this patent in view of our prior sale of iminated copolymer adhesives.' Also the pending application FFD-1834 (Usala) has an earlier priority date** PPG attorneys indicated that they1 Intended i:o file a dis claimer with regard to Claims 4,5,7,15 add 16 in f*S. 3,290,416 because of Ft & F* prior eotamereiaT activity* Our iminated emulsions are included among several commercial products on which Legal will render an infringement opinipii* Gross licensing may result* -6- Our soft acrylic emulsions stabilized at high pH with noh^ionic surfactant, and 0,5-3*3% methacrylic acid are._ con sidered by Legal Dept* to be subject to royalty under Rohm & Haas' U*S* 2,795,564* The royalty amounts to about $100,000/ year and the patent runs till 1974. No royalty is due on 10-4 (EC-11011) or RG-1,119,9 .because they contain more than 3*3% acid* The patent situation for "Polymer Latices and Aqueous Dispersion Paints" has been summarized in a 71 page report by C. E* Bartsch. PUBLICATION STATUSi .y This research should not be published until effective patents are obtained* ACKNOWLEDGEMENTS i Specific references are made in the text td'trfany who have contributed with suggestions, information or, samples. -7- DISCUSSION; The principal defect of most emulsion paints is poor apparent hiding power. It is not always due to low opacity or "loss of opacity on drying (Ref, 2), <It often results from spreading the paint too thinly and poor leveling, (See Appendix 1) Requirements for Improved Leveling There is now evidence that the following paint proper ties result in improvements in leveling - (1) Lower viscosity at low shear rates especially after shearing,, , (2) Lower yield stress in the paint especially after shearingT (3) Slower increase in viscosity and yield stress during the initial drying period (4) Thicker films, (5) Higher surface tension, (6) Narrower striations or furrows due to brushing or rollings Dripless paints especially the "Lueite" type recover their "gel" Structure and driplessness very quickly. This and their high viscosity at low shear rates, and fairly high yield values explain their poor leveling. We need data on the changes in yield value and low shear rate viscosity immediately after shearing at high shear rates* The difficulty is that our rotational viscometers re quire such a long time to register a steady reading (at the very low rpmfs used for low shear rate measurements) that fast changes in the structure of dripless paints cannot be^measured yet. Dr* Patton (Ref, 4) has derived an equation which predicts that for Newtonian liquids the time (t) required.for a given degree of leveling to occur is given by t=0*03.6 X - log Zfi M o whereX - distance between the bottoms of the brushmark t SXJ furrows Zo & Zt = half the depth of the brushmarks at time zero and time t respectively N = viscosity (at the appropriate shear rate if the paint is non-Newtonian) S= surface tension X= film thickness -8- G* G* Bell (Ref* 6) and 0* Lin (Ref* 7) have shown or predicted that leveling is also increased by higher shrink-- age stresses or longer relaxation times respectively* ~ Importance of Yield Stress If paints have a yield stress they will not flow un less the stress developed by surface tension is greater than the yield stress* The maximum stress that can be produced by surface tension can be estimated from the following equation (Ref* 4) Maximum Stress = 248 S Z X The maximum stress that would be developed if a paint had a surface tension of 25 dynes/era* , a striation depth of 1 mil * ( s* 0*0026 cm = 2Z), a wet film thickness of 2 mils (0*0051 cm*) and a brushmark wavelength of 0*15 cms* is Maximum $tress - 248 x 25 x *0013 x *0051 0*15 3 =* 13 dynes/cm2 * A stress of 13 dynes/cm* would not be sufficient to initiate flow of *?Lucite*? Wall Paint since batches of dripless paint have a yield stress much higher than 13 dynes/cm^, e*g*, batch P-730905 of 392-429 had a yield stress of 95 dynes/cm.2, batch 760040 of 392-429 was found by G* C* Bell to have yield stresses of 68 dynes/cra*2 by test method TD-508IT, 49 dynes/cm*2 after' prior shearing at 529 sec*~l, and 100 dynes/cm2 by Beefermah;and Bergren*s method (Ref* 9)* There is a possibility that paints could be formu lated to have sufficient yield stress when undisturbed and un sheared to minimize dripping, hut insufficient yield stress immediately after brushing and rolling to prevent leveling* The present test method for measuring yield stress (TD-508-N) involves waiting 2 3/4 minutes after first shearing for 15 seconds* During this time TIncite* Wall Paint has un doubtedly regained some of its gel structure which may have been temporarily destroyed by shearing under the brush. G* G Bell is studying the possibility of modifying the test method to enable yield stresses to be measured, immedi ately after shearing so that we can measure the break-down of; the gel structure by rolling or brushing* -9- The viscosity of emulsion paints which are pseudoplastic varies from 1000 poises to 0.5 poise depending on whether the measurements are made at shear rates characteristics of leveling (o.l sec0"l) or at shear rates characteristic of brushing (20000 sec."1). If the paint is thixotropic the vis cosity will also vary with the length of time it has been sheared or with the time it has been at rest since last sub jected to shearing stresses. One way to estimate thixotropy is to measure the area enclosed by a hysteresis loop. Figures 1 and 2 obtained by G* C* Bell for "Lucite" Ceiling White 392-429 and an experi mental 10-3 flat paint (8986-159B) respectively suggest that the former paint is not very thixotropic as the up and down curves are not very different. Experimental Paints with Improved Leveling An experimental dripless emulsion paint (8986*159B) containing Veegum and methylcellulose and formulated frSm a modification of 10-3 (in which 80% of the methacrylic acid was added in the last 45% of the mixed monomers gave a bigger hysteresis loop (Fig. 2) and leveled quite well after brushing. These hysteresis loops might be more instructive if they could be obtained over a wider range of shear rates and -especially at the very low shear rates encountered in leveling. Unfortunately our viscometers when used at these low shear rates and rap-^ttf.1 s require several minutes to show's constant reading. The apparent viscosity reading for "Incite"- Ceiling White (at the shear rates important in leveling) actually,in. creases with time of shearing. At o.l secshear raite .'392429 gives the following apparent viscosities on the Haake Rotoviscometer - APPARENT VISCOSITY FOR 392-429 SECONDS ELAPSED SINCE SHEARING _ (POISES ,AT 0.1 SEC^1) BEGUNf - - 850 1510 1550 1580 50 100 150 200 An increase in viscosity with time of shearing, is typical of rheopectic and not thixotropic systems. Apparently the scale readings on the Rotoviscometer at low shear rates re spond too slowly to follow any breakdown in the gel structure. - 10 - A possible explanation for the improved leveling of the aforementioned 8986-159B paint is that its viscosity at low shear rates especially after shearing at 529 sec,,-l is much less than that of "Lucite" Ceiling White. This is illustrated by the following datas APPARENT EQUILLIBRIUM VISCOSITY AT 0,1 SEC,"1 Control of "Lucite" Ceiling White 392-429 Fresh Paint Sample 1600 poises Paint Sample Previ ously Sheared Vig orously__________ 1600 poises Experimental 10-3/ Veegum Paint 8986-159B 800 poises 400 poises The above experimental paint is higher in viscosity at higher shear rates* eg. 3 poises at 529 sec.*-1 vs. 2 poises for "Lucite" Ceiling White. Although this experimental paint leveled much better than the control when both were applied by brush* there was no significant improvement in leveling or appearance for rolled films* The reason for this may be that the shearing rates and shearing stresses developed during roll application are much lower than during brushing. Another explanation for poorer leveling in general for roller applied paints is that the level ing forces due to surface tension would be weaker because of the greater distance apart of the peaks and valleys. The greater spacing between the peaks would be analogous to using a brush which caused widely spaced striations i.e.* a larger and there fore a smaller stress from the equation on page 8. The wet film thickness was lower for roller application than for brush application and this too would decrease leveling* Other formulations of dripless emulsion paints based on this modified 10-3 emulsion and Veegum were compared for leveling* viscosity and yield stress. The effects of Rohm & Haas Aerysol ASE-60 acrylic thickener, their Triton X-405 non ionic surfactant and Dow s methylcellulose thickener on vis cosity and leveling were investigated because these are the additives which control the rheology of "Lucite" Wall Paints. Although differences are apparent in the data on the next page on viscosity and yield stress no improvement in leveling was ob served. Methylcellulose was very detrimental to leveling. Thickener LN caused a large increase in viscosity initially but unfortunately the viscosity continued increasing on aging in these Veegum-containing paints. EFFECT OF ADDITIVES ON RHEOLOGY OF VEEGUM-CONTAINING DRIPLESS PAINTS Emulsion \ Aerysol ASE-60 Viscosity at 0.1 ______ see,,-* % Fresh Triton Sample X-405 (Poise) Sample Sheared at 529 sec.-l (Poise) Yield Stress (dynes/ cm2 TD-508N Leveline IO-3 98 If 88 0 0 0,07 0,07 HG* & PIccopale 0 tt it 0 it n 0,07 98 11 0,07 0 0.5 0 0.5 0 0.25 0 0,25 520 2240 700 1400 1200 1700 1400 2100 450 1700 280 1080 2000 2000 2400 2600 39 Poor 87 88 69 If 83 88 35 ft 63 88 61 ft 67 88 *For this experiment the usual Triton X-405 poststabilizer was omitted from the HG emulsion and added to the final paint (where indicated). When the imination of the 10-3 emulsion was omitted both the emulsion and the paint were considerably more viscous and less stable on the shelf, Veegum-containing paints based on 10 or 10-3 (RC11013 type) were too low in viscosity until methylcellulose or Thickener LN was added. These thickened paints showed poor leveling, 10-4 paints containing Veegum even when applied by brush showed poor leveling when thickened with methylcellulose. Improved leveling after brushing but not after rolling was ob tained for an 10-4/Thickener LN paint pigmented with a base formulated by John Gallager, This experimental base contained Veegum and the other pigments used in White "Luclte" Faint but the usual dispersing agents were replaced by E,, R. Werners8 water dilutable Itaconic acid copolymer, (Ref, 21), This paint bodied excessively on the shelf and caused much worse cracking than 392-429 when both were applied with a 20 mil clearance doctor blade over calcimine. -- X2 = Non Dripless but Splatter-Resistants High Consistency Wall Paints With Improved Leveling The recent commercialization of 394-Line "Incite" Interior Enamels has given consumers possibly for the first time very high consistency paints (Stermer Viscosity - 100- 120 Krebs Units) which show good leveling*, The paints are not dripless because their yield stresses are zero or at least so low we cannot measure them Their high can consistency is advantageous for increasing paint pick-up and for decreasing settling and splatter [ If purchasers of these semi-gloss paints like the application properties as much as did the panelists in the series of tests preceding commercializations it would be worth while to consider the desirability of marketing similar flat paints with improved leveling and appearance There are many consumers who dislike the dripless variety of paints Many even,prefer to use our 2nd Line (ftthe much lower ingredient costP less scrubbable Flowkote Wall Paint) simply because of its smoother texture* If these con sumers are numerous enough perhaps we should give them high consistency paints which apply easily to give uniform appear ance in one coat The chances of succeeding will be Increased if the paints , (1) (2) (3) (4) (5) has good opacity when dry shows an increase in opacity on drying applies easier in a thick film than in a thin film shows a minimum of brushmarks& roller stipples* skips or lapmarks is more splatter-resistant than "Lucltey* Wall. Paint later* Some progress towards these goals will be described Emphasis has been placed also on low mill cost* Low mill cost necessitates using as many as possible of the follow ing approaches*, (1) law solids (2) high pigment volume concentrations -13 (3) large amounts of low cost extenders which give plenty of pigment/air interfaces for "dry-flat hiding" (4) reduced amounts of titanium dioxide (5) emulsions now being manufactured in Fort Madison and used in sufficient quantity to justify bulk handling and storage (6) minimum amounts of relatively high cost additives such as thickeners* glycols (7) low cost diluents for the emulsion such as Piccopale emulsion now used in "Lucite" Wall Paints or low cost plasticizers (8) acrylic emulsions containing more methylmethacrylate and less 2-ethylhexyl acrylate . (9) royalty-free acrylic emulsions such as RC-11011 or RC-11199 Selection of Emulsion their We have concentrated on acrylic emulsions because of (1) ease of manufacture (2) wide formulating latitude (3) good acceptance by consumers partly as a result of our effective advertising of the "Lucite" trade mark ' : ; (4) good stability when shaded with F,, & F**s colefc'ai.i.ts 'There may* howeve^* be an incentive to switch from acrylics to Klehem*s Elvaee vinyl a eefca te/ethylehe emulsions* Dr* R* B Holmes is currently studying this important question. Selection of Acrylic Emulsion We selected copolymers of the IQ-4 tyjie because (1) at the usual pH s ofcour paints and especially in the presence of Triton X-100 they become very vis cous and therefore require less expensive thickener at the desired low solids (2) they show good lapping and leveling in the presence of thickeners derived from high molecular weight nfaleic anhydride copolymers and non-ionic surfactants., (3) they usually give freeze-thaw stable paints even when small amounts of glycols or additional surfactants are added / - 14 - (4) No royalty is payable to Rohm & Haas since they contain significantly more than 2*5% acid* Effect of MMA/2EHA/MAA Ratio on Second Order Transition Temperature - The following table shows the approximate 'Tg'-i's for various ratios? MMA 2-EHA MAA 100 0 0 105 0 100 0 -55 0 0 100 150 *' HG ' 10 "Softer" 10-3 10-3 "Old" IQ-4 Present 10-4 RG-B-91484 9115-132 44 45 45 47*5 45 48 60 76 54 53 52 49*5 51 48 36 20 2 -2 20 31 35 43 47 4 27 4 58 The TgJs were ealeulated for the terpolymers from the values shown for the homopolymers neglecting the effect of im'ination* A high Tg makes the paint harders more difficult to coalesce* Use of Plasticizers A high Tg allows the use of more low cost plasticiser in interior paints if plasticizer migration and embrittlement are only minor problems* Hydrocarbon and styrene-"butadiene emulsions which embrittle and small amounts of dibutyl phthalate have been used previously without problems in "Ludite" Wall Paints* The following table shows the need for about 20 parts of benzylbutyl phthalate/100 parts of binder solids in order to obtain serubability of 50% pigment volume concentration paint based on the RC-B-91484 emulsion (ratio 60/36/4)* -15- EFFECT OF PLASTICIZER ON SCRUB RESISTANCE OF 50% PVC EMULSION PAINTS BASED ON MMA/2EHA/MAA=60/36/4 CONTROLS Parts of Benzylbutyl phthalate 9115-32 9115-33A 20 10 9115-33 392-429=HG Lucite ** 0 - 392-529=BP "Lucite" * TD-530 ** PVC - 45% Scrub Resistance with 1/2% Ivory Flakes* Film aged 1 day for Almo^^daist&ntly Appearance of paint Film after 1000 cycles with 5% Bon Ami (Film aged 1 week) OK for 1000 cycles Failed at 125 cycles almost instantly OK for 1000 cycles slight erosion slight erosion complete erosion (failed at 15 cycles) slight erosion OK for 1000 cycles '> ' 89 it Additional tests showed that good scrubability could be obtained with the following emulsions provided the levels shown below of benzyl butyl phthalate were used? MMA/2 EHA/MAA PARTS OF BENZYLBUTYL PHTHALATE REQUIRED (PER 84 PARTS OF POLYMER SOLIDS) FOR GOOD SCRUB RESISTANCE 45/51/4 48/48/4 60/36/4 76/20/4 * 0 0 20 40 All the paints formulated from the above emulsions using the BP type pigmentation (titanium dioxide/diatomaceous earth) and Thickener LN showed very good leveling,. Improved Opacity In flat wall paints it Is easy to achieve excellent dry hiding power by increasing the pigment volume concentration - 16 - to such a high level that there is insufficient emulsion polymer to occupy the voids left between the pigment parti cles by the evaporation of water* These minute voids- and the large pigment/air interfaces scatter light. When the FVC is high enough there is so much of this type of scat tering that the usual loss of hiding power on drying* can be eliminated, .' The following table shows that there is a loss of hiding power on drying at 50 and 55% PVC# no significant difference between the wet and dry hiding power at 6'% PVC, and a definite increase in hiding power at 75% PVC, The higher PVC*s were obtained by replacing some of the 10-4 solids with the aluminum silicate extender (W-189) usediin "Lucite"- Interior Enamels, *The five reasons for losing hiding power on drying are discussed in Ref, 8, / EFFECT OF PIGMENT VOLUME CONCENTRATION ON HIDING POWER OF 1 0 -4 EMULSION PAINTS 4" *4 a EC IS) i-l H cd csv O CXCM u o<t PO I g ocm O *H CSV O FMCO OMf OM wOt I o M *4* 8 o M a o CO t--f 3 CM an 9 Kf* CM ov c m cn an an co^t co v o c m an 44 44 44 44 44 44 an 8^ ON N Cfv ovoocnr^oocM an an <t ^ cn O CM CO MHO *a 44 44 44 r-4 r~J CM s--I s-4 VO CO CM ^ 'ONN 999 MOH OO CO 00 rann an oo to r-4 HHOOn HON CM vO r-4 00 44 44 44 41 44 44 VO OCM vO<f CSV r^anavoovo an <1* in oo oo co cn r-4 SS* c m av a\ o M*vQvON *4* 44 41 44 44 44 44 OVCONHOOV CO ^ VOVON <fr 7^ OM* O CO o ag o 44 44 44 ov CO CO CM O CO aeo CM an t-l c o c 5n oo an ov VO oo oo r^o OCOVO CM CO O *ao 4r4^o44vr4n4 c m co VO CO CO r-4 Ov<fr an a voooootr*^^ Q o VO CM OOQOOHO CO CM cn<f r-4<f 4o4 4vfo 4o4o: 4c4o 4a4n 4c4o cm k cm veoovoov<^fvKor O M0 CO Ha HoOo 44 44 44 an CM <4 r^O<f*O vo9 co CO - an HC3N *9a i"-* vo vp coco r>. CM an 9 an CM r-4 cM o O CM co CM CM CM CO r4 in 44 44 44 44 44 44 r-4 in 9-4 00 vo CM MO CO 9--4 CM CO 1**'% oo CO vo vo <t s*4 00 9-29 09 09 44 44 44 csv co an <tO-foo ano <t* CM t --4 00 t--4 f's Att Of an co oo CM o an CM o <jh an ov an CM.CM Hco CM ^+|-H -H -ft -ft -H CO O <4 CM r-4 CO CO CM CSV CM in VO 00 OO mvOMt-Mfr O VO CO *-4 0 0 a99 44 44 44 vo an c m co9 r-9vo9 <t CM r-4 /*\ vo o o a9 vo 00 OO 8^ 43oHJ ud cdo rCH4O B 4J 30o) 9 4-1 44 ao 4-1 a<U arl o MM Mm-4 o ^o 3 >> 4J 3 60 *ri > 4-S CM O*tr4 COm 4-1 5 ed S 3H o. > *0 r4 m 4^ cu 3tu e E-2 9 & cn H CM >4 a cd a. *a 4-1 r4 (3) !* mCL* no >> u r0-4) rl cx O H4Jo0&) noHOH^D ao *Q Cd 44 fc3d C0O P<$U o Uii4 99 OO no no i--aH>11*--cHu4 cd td <4-4 44 o 0P) pcd 60 n3Ho <cDd U cu CO CO 3 UCO Q) > Op 0 & a OO P P* P CO ucd P S i*s 99 OO 99 &49 fed9 OO 0 fed0 fed9 OO CO 0) r-4 O >>f O o o o r-4 >> CO Cd ro cd 0) ncs a r-4 3 f^ cd 4-1 *o <ua CO *r4 0) J4 60 CO *3 cd Pd 60 60 33 eQ H *H 3 3 4J u cd <d aoo CO oo ^4-4 <OU O JC CO P *H CO as M 8 tt Ma r-4 O <D*H JO CO 3 co t4 <u 0) 60 J3 0) 4J M B >> O rD 4-4 U 0) U 4J <0 O 4-1 CU 3B CU o &O o o as *3 0) 4-1 *3 4-1 ^ JO *o 0 no 4J cu cd 4-3 r-4 cd 3 r-4 O 3 1-4 a cd HO cd Of: * 4e 18 For maximum hiding power and low cost we need a high pigment volume concentration,, However Lucite Wall Paints and even "Lucite" Ceiling White are formulated at a relatively low PVC (45%). There are several reasons for this. Scrub resis tance***cracking over spackle* stain removability lap uniformity decrease with increasing pigment volume concentration. In 10-4 type paints the decrease seems less drastic and may be acceptable in return for such advantages as better initial appearance in one coat and lower cost. Flat Paint Composition & Properties An attempt has been made to demonstrate the feasibility of the above ideas by the formulation of a low cost flat paint which has improved appearance* (because of better leveling and opacity) than "Lucite" Ceiling White, Appendix II shows a com parison of the composition and properties of this paint 389H-2946 and "Lucite" Ceiling White 392-429. Selection of Pigment Volume Concentration The table on page 17 shows that increasing the pig ment volume concentration (by the addition of extenders) in creases the dry hiding power and decreases the loss of hiding power on drying. If PVC is increased too much e.g, to 75% the scrub resistance is poor and the 85 sheen is too high. Ease of lapping and lap uniformity decrease with in creasing PVC, Lapping is also worse for harder terpolymers containing external plasticizers compared to softer 10-4. How ever at 60-65% PVC the lapping of the externally plasticized paints seem*$atisfactory compared to "Lucite" Ceiling White. Our lapping tests suggest that ethyleneglycol Is definitely necessary for ease of lapping in externally plasticized flat paints at high PVC*s (e, g 65%) but perhaps unnecessary in lower PVC (e*g,, 50%) paints based on 10-4* * Brushouts on hiding power charts and 4s x 4* Upsom boards are superior but larger scale tests with rollers on walls and ceilings are required, ** The lapping properties were determined by lapping the paints on sections of Upsom boards "primed" with a gray emulsion paint (310-125) after 4* 10 and 12 minutes. This is a very severe test for emulsion paints especially during winter months when the low humidity and the absorbency of the substrate cause rapid drying. -19- The higher PVG will probably result in more stain ing and more difficult stain removal but this disadvantage is probably not too important when balanced against the advantages of low costs improved initial appearance and reduced cracking,, The 85 sheen results show that it is possible to eliminate the very large particle size calcium carbomate (W-90) which gives "Lucite" Wall Paints their rough texture Without increasing the sheen significantly. Selection of Thickener The flat paint uses Thickener LN for obtaining high can consistency and good leveling at low solids (for low cost and ease of lapping). This thickener has disadvantages e. g,, poor stability at elevated temperatures (140F.)* and fairly high cost. P,, W Kleinhomer (Ref, 20.) has leads however to other thickeners which should be more stable and lower in cost, A license to make these improved modifications of Thickener LN may be required from General Aniline and Film, An 11/21/67 letter (Ref. 18) was written by the writer to General Aniline and Film at the request of the Patents and Contracts Section to obtain information on their licensing plans but no reply has been received yet. New*Ti02s f or - Hiding-Fewer Pigments Department in the last few years has had several candidates for higher hiding power. In previous reports (Ref. 2*3) we evaluated glass-en cased TiC^j urea-formaldehyde matrix Ti02* calcite-extended TiC^* and the chloride process TiC^* s (Ti Pure R-900 oir-interior for semi-gloss paints* Ti Pure R-960 for exterior semi-gloss paints* Ti Pure R-911 for interior flat paints and Ti Pure R-902 for exterior house paints). Pigments Department now has at least 3 different approaches under investigation. These are the (1) UF matrix TiC^* (2) Edgeraoor work on new oxide treat ments for chloride process TiC^ and (3) potassium titanate milled to form a special hollow agglomerate of particles. The last type will be evaluated in the next few weeks when a sample will become available The following table shows the data obtained when the 2.2 lbs. of Ti Pure R-901 in 392-429 "Lucite" Ceiling White (or Wall White) are replaced by an equal volume of the other Tick's. TiO Hiding Power Wet Drz Oiled - 20 Scattering Coefficient Wet Dry Oiled Paint Ti Pure 595*39 430*33 378*27 3,11*,20 2.11*.12 1.62**09 392-429 R 901 615*25 460*11 3,22*,13 2.23*.02 n Ti Pure 557* 9 448*23 351*21 2*92,,03 2,26**09 1.73*.06 9115-52 e :9u 4163- 574*30 537*27 394*23 2.86*.15 2.69*.14 1.66*.10 9115-53 10 9A* 4163- 599*23 494*13 394*13 3.03*.13 2.41*. 09 1.62*.07 9115-54 112A*-1 UFT-1- 36U*12 345* 3 286'* 2 1,80*.05 1.70*.03 1.18*.01 9115-75A AM-A** *New chloride process pigments with different surface treatments from Dr, A, H, Angerman (Edgemoor) ** A urea-formaldehyde matrix pigment from Dr, A, Bei'dins The highest dry scattering coefficient was shown by Dr, Angerman s 4M3-109A experimental grade which is a con ventional chloride process Ti02 treated with a higher concen tration of hydrous oxides. Because of the low volume concentration of Ti02 in the U-F matrix pigment this pigment is ineffective unless itzis used to replace all or most of the extenders in flat paints. Dr, R C. Gulledge of Pigments Department (Ref, 11) recommends it be used with Ti Pure R-911 and a small amount of celite at a PVC of about -hD%a The following table shows this combination of UF Ti02/R-911/Celite ("40/20/10 by weight) at 58% PVC was superior to a control of BLuciteM Ceiling White (45% PVC) in dry hiding power and in hiding power loss on drying. f na tH H f^. & *r4 00 5-4 NO 0 s *^ tl MI m81 Cl 1 co m 00 ,, ON 4-1 *u; I*} 0) 1 00 VO81 r- GO o oj| 44 I CM 1I ^* SH CO o * 44 CM VO a HI CM r-4 J4H4 . 44 J ,m HHj m * p|1 CM CM H & 4H4 H 6 CM VO O I o CM CM i fidJ 41 ,m VO 81 4H4 H & CO 1 CM CO VO *oj H 4* H CO *H oj CO CM 44 00 CO ON H 04 to , HM -CO CM a|| m *Ho 00 W , 4-*! -0#0 j p CO wI *o 0) *a if g H M , c :> mJS "Mr. H CM ON 60 WO tt rl H*rf P$ 0) C&H o 0) 44 jKj U >> 5 T* - n>a PM <D <P 5-4 S f4^ p e Hc m CO CO 44 o CO crv CO 44 m ON in ocs HM O *J on a 9O ctf o 0O\ f-l CM W? PM t CM HON E-4CO - 22 - The low values of the oiled scattering coefficient suggest that much of the hiding power of the above paints is due to pigment/ air interfaces,, The odor of formaldehyde is detectable in the UF matrix pigments* This would have to be eliminated* The cost of the matrix pigment may be too high if most of the low cost extenders have to be replaced* When samples of odor-free matrix TiC^ are available in bigger quantities this study will be resumed. Peeling and Cracking of Interior Wall Faints on Spackle, Calcimine etc, "Lucite" Wall or Ceiling Paint occasionaly cracks and peels iover many types of surfaces. In 1965 (Ref* 12) Sales re ceived the following number of complaints for the following sur faces. 1965 CRACKING AND PEELING COMPLAINTS AS A FUNCTION OF SURFACE PAINTED Surface Number of Complaints Old plaster (probably includes some spackle* calcimine* etc*) Old Wallboard New Plaster New Wallboard Spackle Wall Paper 488 101 62 24 23 15 The reliability of the above data is questionable. The cost of settling these complaints is high* CRef* 16) In 1966* 907 complaints for poor film integrity were received from the 4,5 million gallons of paint shipped. Cracking and peeling similar to that experienced in the field can be caused by applying "Lucite" Wall Paints over a coating of calcimine* The severity of failure is increased by increasing the film thickness of the calcimine or of the "Lucite" Wall Paint* Better reproducibility has been obtained recently by applying the emulsion paints with a 20 mil clearance doctor blade over wallboard previously painted with a mixture 23** of calcimine*/methylcallulose**/Triton X-405 (*30/5/3 by weight) in 100 parts of water, - The following data suggest that the new HG quality of "Lueite" (Wall and) Ceiling Paint 392-429 fails much less than the obsolete 392-029 quality Rhoplex AC-33/styrene-buta diene/Piecopale sold in 1965* 1966 and part of 1967r BP quality 392-529, Cracking Rating***. pvdr Caleimine/methyl- Calcimine & cellulose/Triton methvTeellulose X-405 , Present HG PLucite" 392-429 o*** 8 a 6 Obsolete "Lucite" 392-029 2 1 BP "Incite" 392-529 2 1 HG Flowkote 389-405 9,5 9 Marketing was asked to check this predicted superi ority for the present 392-429 from the current complaint data, R L, Manley (Ref, 13) confirmed that the total complaint rate had dropped by about half since the obsolescence"of'theIdld quality* though a direct comparison of complaint data for the 2 products was not possible partly because the same labels and codes were used for the 392-029 and 392-429 qualities in 1967- '-on when insufficient HG emulsion was available. An attempt was made to further reduce the cracking of the HG quality by using S, Hochbergss polybutyl acrylate emulsion microgels (with and without polymethylmethacrylate) to replace the emulsions in 392-429, Unfortunately the cracking .was greatly increased. An improvement in spackle cracking resulted from the addition of certain solvents to "Lucite" Gelling Paint or to experimental 10-4 wall paints. The following table shows xylene and some higher boiling aromatic solvents were effective. * H, E, MillandBs "Sweet Amor" brand of Calcimine from Powers and Baeher ** VM-5751 *** 0I0 on scale where 10 ~ no cracking 24 - Cracking Rating* over Ca1c imine/tnethy1- Calcitnine/ cellulose/Triton Methvlcellulose X-405 392-429** 8* It It +1% xylene 9 ft tf *2% 91 10 It ft +2% H-596 (hydrocarbon) 10 If ft +2% H-601 (hydrocarbon) 10 ? ft +2% odorless mineral spirits 10 6 6 9*5 9.5 9 9 50% PVC 10-4 paint ft ff It +1% H-596 St ft IB +2% " :9 10 10 7 8 10 * rated on 0-10 scale where 10 = no cracking or peeling* ** 392-429 - "Lucite" Ceiling Paint - 25 Marketing and the Development Laboratory may wish to test the effectiveness of some of these solvents. The slight odor of the less volatile solvents at these concen trations may be acceptable, especially in the presence of reodorants. High Gloss Spravable Emulsion Paints 60 gloss in the low 80*s and 20 gloss in the 50*s can be obtained in 10-3 type white emulsion paints using existing mill bases, e. g. 548-961 up to about 15% PVC. The propyleneglycol which is present in the mill base 548-961 is necessary for good coalescence and water resistance. It can be replaced by another coalescing agent, e*g 4% butyl carbitol H-143 which was effective in the following tests. EFFECT OF COALESCING AGENTS ON WATER RESISTANCE OF HIGH GLOSS 10-3 PAINTS Coalescing Agent Gloss 60 2,0 Scrubbed with 0.5% Ivory Flakes (Aged 1 day) Scrubbed with 5% Bon Ami (Aged 7 days) None 80 56 failed after 200 cycles failed after 250 cycles 1% Butyl Carbitol (H-143) 82 57 o.k. for 1000 * cycles 2% Butyl Carbitol 82 58 it n failed after 4% " " 84 62 it it 750 cycles o.k. after 10' 4% Cellosolve (H74) 4% Xylene * * * failed after 300 cycles * failed after cycles * * 200 cycles 7% propylenegly col 82 58 o.k. after o.k. after 1000 cycles 1000 cycles * Not tested - 26 - The use of propylene glycol or butyl caibdtolrfoSb:improving water resistance has the disadvantage of increasing the time required for the paint to become resistant to marring by masking tape. However after a 4 hour dry in the laboratory (78F) films laid down with a 3.3 mil clearance doctor blade were hard, enough not to be affected by masking tape (tape was left on for 24 hours). A high gloss white emulsion paint was prepared for H Grube of the Development Laboratory for evaluation as a topcoat for aircraft. This paint 9115-103P should be superior to previous emulsion candidates in water resistance, hardness (after long dries) and hiding power but because of the coal escing agents it probably cannot be taped for a few hours. The tape time will depend on the ambient drying conditions and the film thickness. One of the difficulties with spraying emulsion paints is that they usually leave minute pin holes which become visi ble when the coating on glass is held up to a strong light. C. Victorius has written a backlog proposal aimed at defining this problem and if necessary solving it. Dispersing agents for pigments, emulsifying agents for the polymer may have con tributed in the past to these problems. J. H.Hartshorn has shown that good dispersions of Ti Pure R-900 can be made using only traces of sodium hydroxide instead of dispersing agents. E, R. Werner, Jr, has shown itaconic acid copolymers are good dispersing agents. NaOH and itaconic acid copolymers were evaluated and found to give good dispersions of Ti02 in water after pebble milling. Any foam disappeared after standing for a day if the viscosity was low enough. When these disper sions were mixed with 10-3 emulsion to give low PVC paints the following gloss data were obtained Dispersing Agent for Ti02 60 Gloss 20 Gloss Fishevelne Tamol 731 (0.5 parts Tamol solids/70 parts TiOg) 80 46 slight Tamol 731+Amberlac 165 NaOH n h 4 OH 80 46 none 79 49 slight 69 29 considerable Itaconic acid terpolymer 10 parts/70 Ti02 40 8 30 parts/70 parts Ti02 67 26 If 81 - 27 - A disadvantage of the sodium hydroxide was that it gave dispersions which were difficult to let-down with emul sion without grit formation* Based on the above Tamol 731/Amberlac 163approach appears the most promising* If fisheyeing becomes a problem it may perhaps be eliminated by 3M*s fluorinated surfactants FC-128 & FC-170* V A high gloss black and a high gloss blue were made without difficulty* Exhibits of these were prepared for Dr* A* Armour by spraying the coatings onto aluminum with about 50 psi air pressure* The black required a pebble milling before gloss was acceptable* i Code Golor 60 Gloss 20 Gloss 9115-43 Blue 9115-46AP Black 9115-46A Black 82 78 68 60 53 38 Recently the Development Laboratory has assigned H* Grube to exploit the advantages of emulsion gloss paints for Industrial Maintenance (aircraft, locomotive, gasoline stations etc*) - House Paints By 1972 marketing (Ref* 14) would like to have a new generation of house paints ''offering the present level of .durability but requiring less surface preparation and fewer coats to obtain it,, Ideally one coat should give good performance over chalking, cracking, blistering or. peeling old paint,TM In my last report (Ref* 3) formulating techniques were described for improving the leveling of 10, 10-3 or 10-4 emulsion paints* Also the relationship between build and high shear rate viscosity was given* Photographs were shown of the better crack resistance in the accelerated we^therometer of a more flexible 10-3/Thickener LN paint (310-B-91521)* Since then an earlier modification (310-B-91453) of that paint has cracked over old paint on panels exposed 45 south in Delaware 12 monthsg,(S-21247exposed December 1966)* The cracking is worse than for the #50 control exposed on the same panel* Similar failures have also occurred for 10, 10-3 and 10-4 paints thickened with Thickener LN* The failures are worse for the less flexible 10-4 paints* The paints based on' 28 - 10 (2% MAA before imlnation) contain more than 5 times as much Thickener LN as the 10-4 paints, yet they crack less. It therefore appears that Thickener LN may not be as im portant as other factors e.g. higheraciS level in causing cracking. The cracking is between the old paint and the wood. It is worse When the old paint consists of 347-907 #39 House Paint primer/301-918 #40 House Paint than #49 Blister Resis tant Primer/301-918 #40 House Paint. It is also wofse for 1 coat of emulsion paint than for 2 coats of emulsion paint. When 2 coats of emulsion paint were used the failure was mostly loss of adhesion rather than cracking. In another exposure series #21302 exposed in February 1967 instead of December 1966 failure has occurred ?o far only on one out of 12 panels. On each of these panels the softer 10-3 house paint 310-B-91521 and #50 are being tested side by side over cracked old oil paint. This 10-3 paint 310-B-91521 differed from the earlier 10-3 paints which failed in S-212&7 in that it contained 3% propyleneglycol which improves water resistance and scrub resis tance as shown by the scrub tests on page 25. In the latest 10-3 house paint 310-H-2936 which has been exposed on 2 houses the coalescence and adhesion to chalk were improved still further by the addition of ethylene glycol monoethyl ether. Marketing have listed (Ref. 10) the properties they would like to see improved in the next model of "Lucite" House Paint. These are better hiding, higher build* improved white ness, better leveling, sulfide strain resistance and better mildew resistance. These properties should be obtainable in an 10--3/ Thickener LN paint with barium metaborate (Busan) replacing mica (W-88). Seed formation which occurred in a few weeks in some earlier Busan/10-3 formulations has not occurred after 9 months on the shelf. Effect of Triton Non-ionic Surfactants on Thickening, Stability or Adsorption Triton X-100 (H-609) and Triton X-405 (H-766) which are made from about 10 and 40 moles respectively of ethyleneoxide are the two most commonly used nonionic surfactants in our emulsions and emulsion paints. Triton X-100 is useful for im proving the freeze-thaw stability, the color development and for making paints more viscous at low solids especially when they -29- are based on emulsions containing 3 or 4% methacrylic acid,, Triton X-405 is better than Triton X-100 for decreasing the sensitivity to divalent cations eg. Ba++ from barium raetsL*.- borate (Busan) and for increasing the yield stress and driplessness of montmorilonite-eontaining wall paints,, Its use in "Lucite" Wall Paint for driplessness also results in poorer . leveling and worse spackle cracking The remarkable thickening effect of Triton X-405 even when added with considerable water to 10-3 dripless paints is illustrated by the following data* Effect of Adding 0S5X Triton X-405 and 5% Water an Rheological Properties of a Wall Paint Containing 0*5% Triton X-100 and Veegum ................................................................. Effect on Stortner Viscosity - negligible even though water added* Effect on Viscosity at 529 sec,"^ negligible (actually decreased from 3*6 to 3*3 poise)B Effect on Viscosity at 0.1 sec0"^ big increase from 500 to 2200 poisea Effect on Yield Stress - big increase from 40 to 90 dynes/sq cm* Although Triton X-405 even when diluted with considers able water increases the viscosity at low shear rates of ^ee^guracontaining flat paints it has a different effect in other paints.. Thus 0*6% Triton X-405 (when added to an 10-4 semi-gloss paint (389-B-91433) thickened with the usual Thickener LN) caused a decrease in viscosity from 106 to 57KU,, T& regain the original Stormer viscosity* 4 times the usual level of Thickener LN was required* This higher concentration of Thickener LN which was required because of the presence of Triton X-405 resulted in an increase in the brushing viscosity at high shear rates (11*000 seCe"l) from 0*4 to 0*9 poise and no significant change in the leveling viscosity at low shear rates* Because of this increase in brushing viscosity the applied film thickness and apparent hiding power are significantly increased by this tech nique* The disadvantage is that the extra Thickener LN would cost about 12 cents/gallon* The ease of application might also be slightly decreased especially fen porous surfaces or at low humidities* - 30 - Triton X-100 does not give much protection to 10=4, 10 or HG against coagulation by multivalent cations (e.g. 5% barium hydroxide ,) unless more than 3% nonionic by weight on the emulsion solids are used. Triton X-405 is effective in the same test at 1% level,, Some preliminary data on the adsorption of each of these non-ionics on 10 emulsion particles are shown in the following table. ADSORPTION OF NONIONIC SURFACTANTS ON ACRYLIC EMULSION PARTICLES Percent of Triton added (by weight on water) Percent Triton detected in water by ultraviolet Calculated Percent Triton Adsorbed (or absorbed) on 10 Polymer ____ ... ...... 0 G*05r 0,24 0*48 0*96 1.92 2.87 4.79 Triton* Triton** X-100 X-405 0.1 0.05 0.10 0.5 0.1 1.10 2.70 0.03 0 0.02 0.09 0.08 0.96 2.0 4.4 Triton X-100 0 0.29 - 0.95 3.8 3.9 4.4 Triton X-405 *** 0.1 0.49 0.81 1.8 2.0 1.8 0.81 ^Analytical Results 67-1788 ** Analytical Results 67-2256 *** No Tritons were added yet the Analytical Results suggested some might be present, The above measurements were made by Frank R. Walter using Dr. I. Hazan8s modification of Rohm 6s Haas suggested test method* The emulsions were sent to the Experimental Station for separation by the ultracentrifuge into a supernatant clear layer which was analysed by UV absorption spectroscopy* These results suggest that more Triton X-100 than Triton X-405 (on a weight basis and especially on a mole basis) is absorbed or adsorbed at the higher concentrations. However more Triton X-405 may be adsorbed at lower concentrations of these surfac tants* These tentative observations are being checked by a duplicate set of analyses* The literature on adsorption of - 31 - similar polyoxethylated octylphenols (Ref. 17) suggests that adsorption (on quartz) decreases as the solubility in water is increased by increasing the proportion of ethylene oxide. A better understanding of the role of non-ionic sur factants in emulsion paints is desirable. They have an im portant effect on stability* color development* efficiency of thickeners and their continued use in 10 and HG paints will necessitate a royalty payment of about $100*000/year. A proposal (Ref* 15) has been written for further study of this royalty question. GLOSSARY Hiding Power, - Number of square feet over which a gallon of paint can be uniformly spread to produce the specified con trast ratio* C = 0.98. Contract Ratio. C. - Ratio of the reflectance of a paint film over black substrate of 5 per cent or less reflectance, to the reflectance nf the same paint, equivalently applied and dried, over a substrate of 80 per cent reflectance. Reflectivity, R00 " The reflectance of a film so thick that a further increase in thickness does not change the reflectance. The Kubelka-Munk theory relates the reflectance, R, of a paint film at any thickness, by means of two coefficients? a scattering coefficient S, and an absorption coefficient, K. The absorp tion coefficient is defined as the limiting value of the rate of decrease of transmittance per unit colorant layer thickness as the thickness approaches zero. K = (dTj/dX)^ The scattering coefficient is defined as the limiting value of the rate of increase of reflectance per unit thickness as the thickness approaches zero, the layer being backed by an ideal black backing. S = (dRo/dX)x^0 The scattering is due primarily to the pigment in the paint whereas the absorption is due to both the pigment and the vehicle. When a paint film is so thick that a further increase in thickness does not change its reflectance, then this re flectance is known as its reflectivity, R . For such a thick film, S, K, and Rq o are related by 00 K/S =(1-R )2/2R PVG - Abbreviation for Pigment Volume Concentration which is the % pigment expressed on the total volume of paint solids. MMA - Methylmethacrylate 2EHA W 2 e thyIhexyla c ryla te MAA ~ Methacrylic acid PI - Propyleneimine GLOSSARY ( CONT* D~) 10 - MMA/2EHA/MAA = 45/53/2 (PI/MAA = 2/1) RC-11005 10-3 - MHA/2EHA/MAA =47.5/49.5/3 (PI/MAA=3/l) (RC-11013 or RC-11014) Softer 10-3 - MMA/2EHA/MAA = 45/52/3 (" " " ) (RC-B-87437) HG Emulsion MMA/2EHA/MAA = 44/54/2 Piccopale hydrocarbon emulsion - G-1117 Thickener LN (reaction product of a nonionic surfactant alcohol and methyl vinyl ether/maleic anhydride) _ G-1144 APPENDIX I Effect of Ridges and Valleys of Brushmarks on Apparent Hiding Power Emulsions paints especially the dripless varieties have poor leveling and this makes the apparent hiding power when brushed or rolled worse than the hiding power measured in the laboratory. Laboratory hiding power measurements are made on films laid down uniformly with wire-wound rods. The reflectances are measured on an instrument (colormaster) which is not as sensitive as the eye to the valleys caused by brushing. The leveling was so poor in "Lucite" Ceiling White (392-029 quality) that the average film thickness in the valleys* was only 60% (* 5%) of the thickness in the ridges. The effect of this on hiding power and contrast ratio is shown below. Film Thickness Spreading rate Calculated Contrast Ratio when wet Apparent Hiding Power while wet Calculated Contrast Ratio when dry Apparent Hiding Power when dry Valievs Ridges 1.03*0,25 mils 1,73*0,34 mils 560 sq, ft,/gal. 334 sq, ft,/gal. 0,99 Excellent 0,97 fair 0.99 Excellent 0.99 excellent *Measured with the slit microscope for a film brushed on glhjss APPENDIX II COMPARISON OF THE PROPERTIES OF A LOWER COST FLAT EXTERNALLY PLASTICIZED , ACRYLIC EMULSION PAINT WITH LUCITECT CEILING WHITE Code Binder MMA/ 2EHA/MAA Others Experimental 389-H-2946 "Lucite1'* Ceiling White 392-429 60/36/4 (iminated) 44/54/2 (uniminated HG) benzyl butyl phthalate Piccopale Pigment Volume Con-e. Ti0/gdlo. Extenders 65% 1.8lbs. Ti Pure R-911 W1011/W10Q2 45% 2.2 lbs. Ti Pure &-901 W1012 /W9 0/W101 l/Wlol4/ W-192 Thickeners Solids (by volume) w (by weight) Gallon Weight Thickener L& 31.9% ,51.4% methylcellulose + montmorilonite +nAcrysol 33.9% 50.3% 11.08 .Raw material Cost of Ingredients* Bulk mill cost $1.24 (Approx.) $1.41 $1.41 (Approx.) $1.58 Stormer Viscosity 108 Krebs Units Viscosity (0.1 sec"1) 900 poise m (13000 sec**1) 0.7'>poise Yield Stress 0- Ease of lapping good , 85 Krebs Units 1600 poise 0.6 poise 2 70 dynes/cm4 I very good Lap uniformity good very good Leveling Driplessness very ^ood (brushed) good (rolled) drips but only slowly because of high con sistency fair (brushed) poor (rolled) l ! JI very good Tendency to splatter when rolled too fast bad very bad Texture fairly smooth rough 85 Sheen 2.6 1.3 I. *Includes manufacturing cost of base (pigment dispersion). i APPENDIX II (CONTD) Hiding Power Wet DryOiled 646*32 552*21 356*12 Appearance on Hiding Power Chart (a) When brushed very good uniformity (b) When rolled fair uniformity Resistance to cracking over calcimine very good Scrub Resistance Aged 1 day " 7 days passed 1000 cycles n nn Resistance to staining poorer Ease of stain removal poorer 595*39 430*33 387*27 poorer apparent hiding power t poor uniformity good passdd 1000 cycles n it tt fair fair APPENDIX III LON COST;, EXTERNALLY PLASTICIZED, FLAT ACRYLIC EMULSION PAINT 389-H-2946 Pigment Dispersion 91X5-183 lbs./IQO gal.* 799.60 Tap water 35.40 Triton X100 1.70 Ethyleneglycol 32.40 Thickener LN 22.20 Benzyl butyl phthalate 18.10 Emulsion RC-B-.91484 158.90 Hydrocarbon solvent H-596 22.20 Defoamer G-817 0.90 28% Ammonia 2.70 Tap Water 63.90 PVG 65% Solids (by volume) 31.9% Solids (by weight) 51.4% Ti02/gal. 1.8 lbs 1158.00 APPENDIX III (CONTD'> "48 PROCESS" PIGMENT DISPERSION 548~H2944 FOR LOW GOST FLAT ACRYLIC EMULSION PAINT Tap water Odorless mineral spirits Triton X100 Tamol 731 Phenyl mercury proprionate Ti Pure R-901 28% Ammonia Celite Silica W-1011 Defearner G-8I7 Black colorant W-247 Aluminum silicate W-X002 PVC 96*73% Solids (by volume) 36.93% Solids (by weight) 62.29% 35.54 1.17 .33 .94 .01 22.35 .29 17.35 .26 .01 21.75 100.00 BIBLIOGRAPHY I Mb J* McDowell, "Semi Gloss Emulsion Paints" R-65-112 2# M 4 McDowellp Leads for Improving Serai-Gloss and Flat Paints p Leveling** Lapping and Hiding Power* R-66-59 3# M# J. McDowell, Emulsion Paint Research, III* R-67-54 4# Tffi G Patton8 s book*, Paint Flow and Pigment Dispersion# 5 Smith et0 al The Physics of Brushmarks JOGCA 44* 618 1961* 6* G* C* Bell* Marshall Research Laboratory Monthly Report1 October, 1967* 7 0* Lin, Memorandum Report RM-67-11* 8* M# J* McDowell, Hiding Power of Emulsion Paints R-65-22* 9* Beeferaan and Bergman, J* Paint Tech# 38, 9, 196b* 10* J* L* Palermo to W. J* Starr Files 2050 - 10/31/67* 11# R G# Gulledge Urea Formaldehyde Matrix Pigments* 8/16/67 12* T# G, Brown to M* J* McDowell 4/28/66* "Lucite" Wall Paint Complaints - Cracking and Peeling 13o R L Manley to M, J# McDowell 11/30/67 "Lucite" Wall Paint Cracking and Peeling Complaints# 14# Marketing Product Objectives* 1/19/68 15# M# J* McDowell to G* E# DeBoer 1/19/68 Files 1702 Proposed Backlog Proposal# Improving our Patent Position in Emul sion Paints# 16# T* G* Brown to H, J# McDowell 12/22/66* Peeling of In terior Paints* 17# H N* Dunning1 Ind# Eng* Ghera*, Chem# Eng# Data Series 1957, 2, 88# 18# M# J# McDowell to J# Grande (of General Aniline) 11/21/67# 19* R* A# Schulze, Jr* RM667 20* P W* Kleinhomer R-68-5 21# E* R,, Werner, Jr# R-68-2 tf : t t- ' FIGURE 1 , 392-429 (P-760040) "LUCITEU CEILING WHITE j 1 EFFECT OF SHEAR RATE ON APPARENT VISCOSITY I (from 3.3 sec."1 to 529 sec."1 & from 529 sec.**1 to 3.3 sec."^-) . TABLE OF CONTENTS INTRODUCTION,, 1 OBJECTIVES a*att*a*<iff<ift|iot*ti*Q>ftt 1 SUMMARY AND CONCLUSIONS Wall Faints *& *.** -<>** I Houss Psints ...,,. *.* *., 2 Gloss Emulsion Paints3 Nonionic Surfactants <,,<*'^3 ACTION TAKEN OR PROPOSED 3 PATENT STATUS Status of Prior Proposals <> 3 New Proposals o,-,*,*,*,*,,*,*,,,',,,***,,,,*,*,**,*,****),** A Competitive PatentA PUBLICATION STATUS o,6 ACKNOWLEDGEMENT S **** * * *' 6 DISCUSSION 70-0 Oft ftftftftft-ftftftftftftft Requirements for Improved Leveling7 Importance of Yield Stress , ee*s09,,ftoo, 8 Experimental Paints with Improved Leveling................................... 9 Non-Dripless but Splatter-Resistant, High Consistency Wall Paints With Improved Leveling ** 12 Selection of Emulsion .................. 13 Selection of Acrylic Emulsion....... 13 Effect of MMA/2EHA/MAA Ratio on Second Order Transition Temperature ................... 1A Use of Plasticizer.ss>a................................... 1A Improved Opacity15 Flat Paint Composition & Properties...................... 18 Selection of Pigment Volume Concentration..,.,.....,.,... 18 Selection of Thickener...19 New Ti02*s for Hiding Power ............................ ............. ......................... 19 Peeling and Cracking of Interior Wall Paints on Spaekle, Calcimm@ etc, 22 High Gloss Sprayable Emulsion Paints25 .House Paints . 27 Effect of Triton Non-ionic Surfactants on Thickening, Stability or Adgorptloa^.. Q {& <?& <s> &<? e o ^ 38 APPENDIX I, II, III BIBLIOGRAPHY GLOSSARY TABLE OF CONTENTS FIGURES I, II Distribution C. W. Theobald. Wilm, F$F) T_ Tl1,, J. S. Allen, " " ) ln iwrn J A* Klacstnann, " P, I, Poindexter," w W. D. Lawson, w ") R. B. Davis, " ") InTurn C. F. Kalb, " ) Poromeric Research Lab* Library (1) P. J. Graham, Exp* Sta. N. G. Fisher, Exp* Sta, G. .I. Mulholland, Flint Information Servians, Lab* (217)^