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Патент USA US2117366

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"Patented May 177, ‘1933 “
I 2,117,366
-2,1\1':v,_36c ~
HaroldF. Saunders and Charles Donald Downs,
’ Chicago, Ill., assignors to The Sherwin-Wil
liams Company, Cleveland, Ohio,‘ a corporation
0f Ohio
No ‘ Drawing.
Application December 7, 1935,
Serial No. 53,428
5 Claims.
‘ (Cl. 134-58)
special interior ?nishes where bodied oils, treated
This invention relates to the treatment of pig-,
‘ments and the like, and particularly to the neu
oils, varnishes ‘and varnish gums are considered
essential to obtain certain desirable effects in
tralization-of the effect of adsorbed water thereon.
It is well known that a relatively high degree brushing, gloss or ?atness, ?lm hardness and
the like.
, From a theoretical standpoint, water which isv
in the process known as “pulping” which com-.
prises the replacement of water from an ‘aqueous retained adsorbed on ‘the surface of hydrophilic'
suspension of the pigment,‘ such as is obtained in particles does not as such émulsify to form the
of dehydration of‘ pigments may be accomplished
phase of an. emulsion in the water-im
precipitation, aqueous quenching, or other proc-‘. internal
miscible liquid, but this internal phase consists
ess operation, by a liquid substantially non-mis
cible with water; and that in such pulping process of the combined pigment plus adsorbed water.
elimination of water down to 0.5 to 2% of the
"pulp” is the practical limit to which water is
The apparent effect on the pulp is a shortness,
or a short-?ow grainy-appearing paste. Further
‘removed. To eilfect as large a percentage ‘of re
15 placement as this, special agents are resorted to,
agents previously mentioned does not change
addition or retreatment with the usual treating‘
effect or appearance, since the vemulsion is
which, by contact with the pigment, cause it to vthis
already stabilized, and the water not far from
wet preferentially in oil rather than water. Some‘ the natural solubility of water in the liquid, hence
of the agents frequently used are drying oil fatty it cannot be removed or replaced and there is
acids, soaps, sodium phosphate, borates, resi- ' no tendency for it to leave the pigment particle. 20
nates,_r_esins, amides or alcohols,'naphthenic acid,
and the like.
. We havev discovered that when a substance
such as lecithin, obtained from soya bean oil,
or a modification of lecithin, obtained by heat
Theoretically, complete replacement of water
can be obtained; but this complete replacement
is never reached in commercial practice, since
‘the pigment particles are frequently somewhat
2 coalesced into aggregates and thestreating agents
ing, bleaching, purifying,_or otherwise-treating
either soybean or other lecithin, is added to the
' pulp in- a“ small proportion.
' to 2.0%, a modi?cation of
of approximately 0.5
the emulsion is ob
are unable to reach the surfaces of the interior tained and, an immediate visible change takes
particles of these aggregates. In addition, the ' place,
the pulp becoming noticeably of a long,
waterdmmisciblel liquids will in themselves re
and losing the grainy appearance.- Fur .30
tain a certain percentage of water in a partially
ther, when such pulp is_reduced with the afore
30 emulsi?ed condition.
_ ’
The. pigment dehydrated by a pulping process mentioned bodied oils, heat-treated oils, var
possesses some very distinct advantages over the
same pigment dehydratedby the customary pro->
a cedure of ?ltration and drying; since the latter
introduces certain physical and chemical changes,
disadvantageously a?ectlng color, opacity, tex
nishes or varnish gums, which areintended to I
be referred to in the claims by the expression
“oil paint vehicle”, they are not curdled and their
natural properties remain una?ected.
vThe‘ ‘percentage of lecithin required is not
critical. Partial effect, is obtained where, lower
ture and‘ wettability.-_,;For this reason, the pulp _ percentages than specified are used, and a greater
ing process of dehydration is commonly resorted
to wherever the unavoidable presence of the small
. amount of water is not considered harmful.
Thus,,ior example, pulped white lead in lin
seed oil, commonly referred to as “lead-in-oil”
amount may e used, but since the desired result
is obtained within the range speci?ed, any excess
is merely wasted.
The superior qualities of the pulped pigment,
‘such as ?ne texture and softness, a high degree
is a- standard commercial article, its major use oi whiteness or color and markedly higher opac
being for exterior house paints by further addi
' ity, are thus made available.
tion of drying oils, thinners, and driers. '
The use of pulped pigments has not heretofore
been practicable when further reduction was to
be made with bodied oils, varnishes, natural or
, synthetic gums, and the like, because the water
present in the pulp produced a livering or clab
beringgby change in the solubilities of these ma
terials so that‘ they would leave solution and
As an example of_ the practice of ‘this invention: .
Two pounds of lecithin are added to 100 lbs. of
a lithopone pulp carrying approximately 1%%
'of’ water and obtained by replacement of water
from an aqueous suspension of lithopone by a
liquid consisting essentially of 98%‘ mineral spirits
and 1%%- linseed oil, and %% linseed oil fatty
, Use of the zinc sulphideipigments, such as litho
acids. "Thepaste thus made is stirred until the
lecithin is well dispersed. An immediate reduc
pone and similar high opacity pigments, in pulped
form, has hitherto been limited since not only
‘ does the pulping of these pigments result in the
cordance with our invention is shown by the
higher proportions‘of water, upwards of 1%, but
pigments are, in the main, utilized for
tion or the short ?ow is apparent. ,
The- supe'riorlty of this product made 'in ac
following comparative tests:
1.‘ 1010 lbs. of lithopone,
dried in the usual l‘a‘»
manner, ‘was made up into a ?at wall ?nish. with paint vehicle, a drier, pigment material and
the usual ‘?at liquids.
I p
I I,
2. An attemptto make a ?at wag ?nish with
lecithin, said pigment material comprising a
“pulpedff pigment containing. a small percentage
the same liquids as in No. fly/but usingpulped ‘ of water and the amount of the lecithin being
I lithopone instead 91 the'dried ilthopone, ‘fail
between one-hair and two per cent, by weight, »
\oasaid pigment.
_ 3. A ?at wall ?nish was made with'the same
v /lihuids as-in No. l and No. 2.but using lithopone
in lecithin-treated'pulp form equivalent to only
, ZQAT‘eoating/ composition consisting of an oil
paint vehiclermdrier. Pigment material and
lecithin, said pigment material comprising
"pu1ped” lithopone contamngq than two per 1.
I. 910 lbs. olvlithopone onthe dry base. ,
On painting similar surfaces in the usual way . cent or water and the amount of
.thin being
with No. 1 and No. 3, not only was No. 3 whiter . between one-half and two per cent, by\weight,\
than No. 1 but it showed markedly greater cov- . of said‘ lithopone.v
ering power.
A ll
3. A "pulped” pigment,‘ for coating composi
The two paints were then carefully measured tions, having a water content 01' less than two 13
on an opacimeter using the Marten’s photometer ~ per cent and having incorporated therewith in a
in accordance with the Bureau of Standards
method in Technical Paper No. 306, dated Jan
uary 16, 1926, where it was ‘found that whereas
10.5 lbs. of pigment in ‘No. 1 were required to
bring 500 square feet of surface from black to a
contrast'ratlo of 96, in the case of No. 3, only
8.94 lbs. of pigment were required for the same
state or complete‘dispersion an amount of lecithin
which is from one-half to two per cent, by
weight, of the pigment.
4. A "pulped” lithopone having a water content
oi‘ less than two per cent and having incorporated
therewith in a state 01' complete ‘dispersion an
amount of lecithin which is irom one-half to two
per cent, by weight, of lithopone.
5. The herein described‘ method of improving
35 by
' the
e diilerence
two. methods
per is,
of lithopone prepa
the covering power of an oil-emulsi?ed “pulped”
for paints, having a water content not in
Sq. ft. per lb.~ of pigment ‘ pigment
excess of two per cent of the pigment, by weight,
black to 96 contrast ratio
ularly dried lithopone__>_--_ ______ __"I____ 47.6
which consists in adding thereto and completely _.
swing thus
of the plant.
’ ii.
w-w-i. our invention, what we
coating compontion
of an oil
dispersing therein an amount 01 lecithin which
is from one-half. to two per cent, by weight,
F. saummas.
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