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PRODUCT DEVELOPMENT REPORT COATINGS AND RESINS GROUP LABORATORIES
AUGUST 1961
GLD006570
N 2282
In all of the above recommendations we have used Y1800 as a generic description. In every place where Y1800 is recommended, Y1850, Y1867, Y1892 or Y2218 could also be employed. In general, the gloss house paints will protect a poor prime coat where a flat breathable finish cannot. It becomes more and more apparent that flat finishes must have primers of outstanding merit in order to develop good durability in a paint system. Any flat finish over a questionable primer can result in very serious peeling, flaking and generalized failures.
We hope this clarifies any questions you may have had. If not, please contact us.
S. T. Bowell
LEADED ZINC OXIDES IN HOUSE PAINTS
We have changed leaded zinc pigments in house paint to obtain lower costs. For many years we used W-6 (351 leaded zinc oxide) in Y1800. We then changed to use W-35 (10-20% leaded zinc oxide) and W-l (lead sulfate), keeping the lead/zinc ratio still at 35/65. This gave us a savings of 7t per gallon in Y1800. We are now using W-249 (18% leaded zinc oxide) in Y1800A. You will note that we have kept the zinc oxide level the same while the lead sulfate has been lowered.
The greater efficiency of the lead in W-249 (Ozlo 18H) is obtained by the elimination of the inert lead sulfate (PbSO^) component from the basic sulfate white lead. Basic sulfate white lead, as such and in leaded zinc oxides, is a mixture of monobasic lead sulfate and normal lead sulfate of about the following composition: PbO. PbS0^+3PbS0^. This means that only one in five of the atoms of lead in basic sulfate white lead is basic and, therefore, available to react with fatty acids in the paint and paint film. The lead is, therefore, only 20% efficient.
The lead in W-249 is present as straight monobasic lead sulfate, PbO.PbSO,. One in two of the atoms of lead is basic and available to react with fatty acids. The lead is, therefore, 50% efficient or two and one half times as effective as the lead in basic sulfate white lead.
We have been checking out this approach for seven years in Y1800. Our exposures have shown equal durability for W-249 and we now have an additional cost savings of llq per gallon in Y1800.
In essence what we are doing Is replacing 5# of W-6 (35% leaded zinc oxide) or any blend of equal lead and zinc, with 4# of W-249 (18% leaded zinc oxide). You will note that the zinc oxide content remains the same.
OLD006571
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Our hope is to use W-249 in all Y Line house paints,where leaded zinc is used thus having only one leaded zinc pigment in stock.' ~
J. E. Southwick
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TESTING OF COMPETITIVE PVA PRIMERS AND COMPARISON TO Y3525
Several competitive PVA primers have been submitted to us from various regions to be checked. These primers are Martin Senour PVA Sealer White B5086; Continental Paint Company's PVA Primer; Benjamin Moore & Co. Quick Dry Primer Sealer and Sherwin-Williams Painter Craft PVA Wall Primer. These paints were compared to Y3525-G which is currently being relabeled as a primer and a special version of XM-60043 special primer employing Glidden Latex.
The primers were checked for package and film properties with the following
results:
Package
Film
C8ndition
Odor
Hide
Appearance
Gloss 60
Martin Senour
4"separation sweet fair
rough,poor
18
smooth,restir
texture,
easily
glossy
Continental
good.restir
ok
good
rough,poor
4
well
texture, small
, " Benjamin Moore
2"separation,
particles and .
; .- ;.... _ j-'.''- ; agglomerates -
ammonia fair
smooth, some . v
. : -T;i ** V
, 4.;
restir easily
fish eyes
Sherwin-Williams
1-1/2"
ok
fair
smooth,somewhat
12
separation,
glossy
restir well -
Y3525 .. : ; ;
good,smooth, - ok . *
excellent smooth.even .
4
heavier
Exp.XM60043
1"separation, ok
good
smooth,some
6.
DN1151
smooth,restir
small foam holes
well
The Martin Senour and Continental paints had many large agglomerates and
undispersed pigment particles breaking the surface of the film which is an
undesirable property. Only the Y3525-G had an excellent hide.' This factor
helps because there is more assurance of complete hiding with the finish ..
coat. The gloss is usually a good indication of a primer. In general, those
paints with high gloss have the best holdout properties but even so the Y3525.,
at lower gloss had good holdout properties. With this lower gloss it provides
more "bite" for the topcoat* .
- ..
The primers were tested for sealing properties over bare upson board and bare
plaster with the following results.
-ri
GLDQ06572