,-I
INDUSTRIAL A N D ENGINEERING CHEMISTRY
1944
Wben the bonding tima are obtained for the vsriouS panels ahown in Figure 8, theu individual thickm€s?~ are Plotted a& cum tima (Figure 10) to give a d e C u N e to be used in the bonding of panels of various thicknesses a t a Platen temPeratUre of a000 F. The cum time for bag-molded structures can be determined
187
ACKNOWL&DGMW
D. K. Rider and W. H. G r d ably cooperated in obtaining much of the data and preparing this paper. W. Niederhauser hss slao been a 8 o m of valuable assistance and advice. LITERATURECITED
DURABILITY OF LUSTERLESS ENAMELS Influenee of the Binder i. E. Beck, GROUND,m * B E R D ~~ O V I N G
?
.
HI8 pper is the second of a series on the relation betwean the durability and composition of lusterleas enamela The first pper’ gave detaila of preparation and exposure of expmimmtal enamela These procedumn were followed in the preaent work The binders studied may be bmken into two main clsssea: o i l - m o W a l k y a and resin.and-oil-m&d alkyds. A few orthodox varniahen ara included to complete certain experimental U d m . The various bindere were incoqmated into a standard lusterleas olive drab enamel formula (Table I). This formuls waa used without change with the exception of thoee pmducta containing chlorinated rubber (pinta44 to 62) where the percentage of pigment by weight on solids bseis aas eat a t 61-68 hues of performance lepuirementa. Total mlidn of the pinta waa not leas than 60% by weight, and waa inu‘ead where nwssry to obtain sstisfadary viscosity. Driera used, on vebicle solids basis, w m : 0.03% cobalt, 0.01% manganese, and 0.20% lead In a number of eases CertaiD departures fmm the stgndard drier contentd were necwawy (Table 11). Enamels were ground in a ball mill. Painta were exposed a t Baltimore, Md., for one year on deel panels as described in the 6rat papa?. All paints w m airdried. Exposure mdta are given in Table 111, and eduatiom were made by the Bame observer. Flatinga for hardneas snd adhesion were eatisfaunlw abated otherwise in Table 111. 2
I-.
E m . C ~ B Y .3% . S84 (1948).
Tnsm I. F o m a a ME BINDS~R
Compasitiom given are bpssd on vehicle mlida Additiono were made on a c o l d a t basis except wbem othmvim indicated. OILMODIFIED AlXYDS
Difierences in durabiity between Iusbrlem enamels based on alkyd Rsins prepared with different oils are not w t .Tung appara to be the least eatisfactory oil for appearance retention. The only psnela showing poor film pro&@ were the W M ) linseed-tung; 50-50 lhesad4ehydrnted castor is beat in appearance retention by a narrow marpin. Very little differences in performance were found betwem alkyd Rsins containing 25 and 35% of phthalic anhydride.
RESIN- AND OlLMODlFIED ALKYDS
phenolic reaine. of the types studied. lower the apPem8nm of lusterlea enamelg Thin deet is prinupauY due to inoreased chalking. orthodox phenolia vnrniab chslk to the w i n t where they are unaatisfactors for outdoor E&& in lusterlea &ela Up to 10% by weight of phenolic reein or an equivalent weight of phenolia varnish @anbe incorpomted into the a k y d resin with no loes in appearance retention. The excellent film properties (othet than chalkinp) of phenolic resins are demonatmted by the fact that 88 much an 50% of phenolic resin a n be cold cut into the alkyd resin with M loas of metal-protecting properti@,even though the oil length of the binder is thereby reduced to approximately 8 d o m . Chlorinated r u b t e - a k y d resin mixture8 pmvide eminentlp eatisfaatory vehicles for lusterless emamek
INDUSTRIAL AND ENGINEERING CHEMISTRY
158
Vol. 36, No. 2
OF BINDERON APPEARANCE RETENTION AND FILM PROPERTIES TABLE 111. EFFECT
Panel KO.
Binder" No. 1 Linseed alkyd 25% P.A. 2 3 4 5
Linseed alkyd' 35%, P.A. 75-25 linseed-hung alkyd 2 5 7 P.A. 75-25 linseed-tung alkyd' 3 5 4 P.A. 50-50 linseed-tung alkyd: 25% P.A.
6
50-50 linseed-tung alkyd, 3570 P.A.
7
50-50 linseed-soybean alkyd, 25% P.A.
8 9
50-50 linseed-soybean alkyd 35% P.A. 50-50 linseed-dehydrated &tor alkyd, 25% P.A.
10 50-50 linseed-dehydrated 35% P.A.
castor alkyd,
11 50-50 linseed-sunflower alkyd 25% P.A. 12 50-50 linseed-sunflower alkyd: 35% P.A. 13 50-60 linseed-perilla alkyd, 25% P.A. 14 50-50 linseed-perilla alkyd, 35% P.A. 15 50-50 linseed-steam-distd. sardine alkyd, 25% P.A. 16 50-50 linseed-steam-distd. sardine alkyd, 35% P.A. 17 Soybean alkyd 25% P A 18 Soybean alkyd' 35% P.A: 19 75-25 soybeanltung alkyd, 25% P.A. 20 21
75-25 soybean-tung alkyd 35% P.A. Dehydrated castor alkyd, i 5 % P.A.
22 23 24 25 26 27 28
Deh drated castor alkyd, 35% P.A. Per$ alkyd, 2 5 7 P.A. Perilla alkyd 35# P A. Steam-distd. 'sardfne h k y d , 25% P.A. Steam-distd. sardine alkyd, 35% P.A. 25-gal. tung-phenolic A varnish 26-gal. 60-40 tung-linseed, phenolic A varnish
29 30 31 32
varnish
chlorinated
rubber-70%
chlorinated
rubber-70%
Moderate
1 0 7 phenolic A-90% alkyd A A-75& A-507 varnisg varnish varnish varnish
alkyd A alkyd A A-907 alkyd A-80d alkyd A-609 alkvd A-508 alk>d
40
1 0 0 7 ~phenolic varnish A
41 42
I 0 7 phenolic B-90% alkyd Bb 10% phenolic C-90% alkyd Bb
43
30% phenolic C-70% alkyd BS
44
30% 5-cp. alkyd C 303kykyd5;p.
45 46 47
+
Slight Slight Moderate Moderate Moderate Slight Slight Moderate Slight Moderate Moderate Extensive Moderate Slight Moderate Slight Moderate Slight
33 20% phenolic A-807 alkyd A phenolic phenolic phenolic phenolic phenolic phenolic
+
Panel NO. Binder" NO. 48 50% 10-cp. chlorinated rubber-50% I alkyd C 49 40% 10-cp. chlorinated rubber-lO% tri- 1 cresyl phosphate-50% alkyd A 50 30% 10-cp. chlorinated rubher-70% 1 alkyd C 51 30% 10-co. chlorinated rubber-70% 1 alkyd A . 62 10% 10-cp. chlorinated rubber-90% 1 alkyd A 53 53% 20-cp. chlorinated rubber-22% tri- 1 cresyl phos h a t e 2 5 alkyd C 54 56% 20-c cRlorinate~rubber-19% tri- 1 cresyl p%osphate-25% alkyd A 1 55 50% 20-cp. chlorinated rubber-50% alkyd C 56 40% 20-cp. chlorinated rubher-lO% tri- 1 cresyl phosphate-50% alkyd A 57 30% 20-op. chlorinated rubber-70% 1 alkyd C 58 30% 20-cp. chlorinated rubber-70% 1 alkyd A 59 20% 20-cp. chlorinated rubber-80% 1 alkyd C 60 20% 20-cp. chlorinated rubber-80% 1 alkyd A 61 10% 20-cp. chlorinated rubber-90% 1 alkyd C 62 10% 20-op. chlorinated rubber-90% 1 alkyd A 63 50-gal. tung-ester gum varnkh 1, 2 64 50-gal. 60-40 tung-linsecd ester gum var- 1, 2 nish 65 25oJ ester gum-759 alkyd A 1,2 66 10% ester gum-909 alkyd A 1 2 67 73% 25-gal. linseed ester gum varnish- 1 27% alkyd A 2 68 29% 25-gal. linseed ester gum varnish- 1, 2 71% alkyd A 69 2 5 2 limed . rosin-75% alkyd A ;, 2 70 10 limed rosin-QO% alkyd A
A A
A
A
537, 10-cp. chlorinated rubber-22% tricresyl phosphate-25% alkyd C 56% IO-cp. chlorinated rubber-19% tricresyl phosphate-25yo alkyd A
Slight Slight
+ +
Formulas calling for relatively large amounts of chlorinated rubber (above 35 per cent of the binder weight) require plaaticizing with tricresyl phosphate or other plasticizers, but no loss in film properties is experienced. Chlorinated rubber possesses three advantages in addition to its excellent chalking resistance in lusterless enamels-rapid drying, high chemical and water resistance, and good flatting efficiency; lower pigment volumes can thereby be used than with alkyd resins. Ester g u m varnishes are poor in appearance retention in lusterless enamels. Modification of the alkyd resin with even small amounts of ester gum, ester gum varnish, or limed rosin reduces appearance retention. Although cumar resin is unsatisfactory for cold-cut additions t o alkyd resins, it produces acceptable lusterless enamels when moderate quantities of a 25-gallon varnish are added to an alkyd resin (approximately 30%). urea-formaldehyde resins in quantities up to 3 0 7 ~produce binders Of good appearance retention and film used to modify alkyd resins. These observations apply to the ~
Color Change and Chalking after Exposure Slight
+ + Slight + Slight +
Slight
Slight Slight Slight Slight Slight Slight Slight Slight Slight Slight Slight Extensive Extensive Extensive Slight Extensive Moderate Moderate Moderate Moderate Moderate Slight
0
Extensive Extensive
5 % phenolic A-95% alkyd A
34 2 5 % 35 50% 36 1 0 9 37 20.9 38 4 0 9 39 50%
Color Change and Chalking after Exposure Slight Slight Moderate Moderate Moderate; film powdery Moderate: film powhIrderate: rlerv --.~ dery Slight Moderate Slight Slight color change: chalkinrt no chalking Slight Slight color change; no chalking Slight Moderate Moderate Slight Moderate Slight Slight color change; no chalking Moderate Slight color change; n o chalking Slight Sljeht Slight Slight Moderate Slight Slight Moderate Slight Slight Moderate Slight SlighB Extensive Extensive
li
5-gal. linseed limed rosin varnishalkyd A 5-gal. jinseed limed rosin varnish-
71 72 73 74 75
alkyd A 87% 2 5 - ~ a l .linseed cumar varnish-13% aikyd A 77 10% urea-formaldehyde-90% alkyd D (unbaked) 78 20% urea-formaldehyde-SO% alkyl D (unbaked) 79 30% urea-formaldehyde-70% alkyd D (unbaked) 76
1 2 1, 2
Extensive Moderate
;,
Moderate Moderate Moderate Slight Extensive Moderate Moderate Slight Slight
1 2 1 2 1 2 1 1
2
2
Moderate Slight
(1 P.A. = phthalic anhydride. phenolic A = p-phenylphenol-formaldehyde condensate. phenolics B and 'C = glycerol-reactive type phenolic resins; linseed-modified alkyd resin, 35% P.A.; alkyd B = linseedalkyd A modified alkyd resin, 30% P.A., cooked from components in presence of reuired phenolic resin: alkyd C = linseed-modified alkyd resin, 3070 P.A. used because of superior compatibility with chlorinated rubber); alkyd D = linseed-modified alkyd, 45% P.A.; phenolic varnish A = p-phenylphenol-formaldehyde condensate 5090-tung oil 5070 (on vehicle solids). b Cooked, not cold cut.
=:
s
air-dry use of the enamels. Such resins are commonly used for baking purposes only, but it was considered desirable to investigate their air-drying performance in view of the conditions of army usage. Further data on urea-formaldehyde and melamine resins will be included in a later report. ACKNOWLEDGMENT
The author wishes to express his indebtedness to the Bakelite Corporation, H. B. Davis Company, Ferbert-Schorndorfer Company, Glidden Company, Jones-Dabney Company, Inc., Reichhold Chemicals Inc., Roxalin Flexible Finishes, Inc., and Sherwin-Williams Company for their cooperation in preparing the paints. THISreport is based on laboratory findings and is presented only for i t a technical interest. I t is not to be considered in the light of an official Government pronouncement, nor is adoption of any of these recommendations or formulas reouired of manufacturers dealing with t h e Government. directly orindireotly.
